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Item Synergetic effect of the addition of Nono-Silica in Red Clay-Based Geopolymer product(2024) Gurung, Sunil; Arvind PathakAvailable in fulltextItem GREEN SYNTHESIS OF SILVER/ZINC OXIDE NANOCOMPOSITES USING LEAF EXTRACT OF DESMOSTACHYA BIPINNATA (KUSH) AND STUDY OF ITS PHOTOCATALYTIC ACTIVITIES(Amrit Campus, 2024-10-28) Anita Bhattarai; RameshRemoving organic pollutants including textile waste solution and dyes has become an essential requirement for maintaining a secure and healthy environment. Therefore, the present study deals with the synthesis of ZnO and Ag/ZnO nanocomposites using the leaf extract of Desmostachya bipinnata. The leaf extract of Desmostachya bipinnata contained a different bio-active compound that serves the dual purpose of acting as stabilizing and reducing agents. Out of various methods, green synthesis has been extensively employed for its simplicity, low-cost, and eco-friendly nature. The characterization of the as-synthesized ZnO and Ag/ZnO nanocomposties were subjected to ultra violet visible (UV-vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). XRD pattern revealed the crystalline nature of nanoparticles. The crystallite size of Ag/ZnO was found to be 12-14 nm, according to Debye Scherer formula. The synthesized NPs and NCs were used for the catalytic photodegradation of Methylene blue (MB). The MB was degraded at room temperature under exposure to UV light. The degradation efficiency of ZnO, and 25 % Ag/ZnO were found to be 79 % and 85 %, respectively. Therefore, it was found that Ag/ZnO nanocomposites have potential to degrade MB as organic dye, and can be used for wastewater treatment.Item Study on effect of sodium stearate surfactant in mixed solvent media(2024) Yadav, Brahma Deo; : Prof. Dr. Ajaya BhattaraiThe specific conductivity of sodium stearate(SS) surfactant in double distilled water, different percentage of methanol are studied by conductometric method at three temperatures (298.15, 308. 15, 318.15) K. The Critical Micelle Concentration (CMC) of sodium Stearate is determined at all temperatures. CMC is increased with an increase in temperature of the solution. the CMC of SS in distilled water at (298.15, 308. 15, 318.15) K. is 0.0008M, 0.0010M, 0.0020M was obtained . The specific conductance is decreased with increase in percentage of methanol in the solution. The corrosion rate of surfactant is observed. FESEM image, EDX graph shows the purity of the sample. The percentage of elements present in sodium stearate surfactant is explained by EDX data. The percentage of C, O, Na, sodium stearate surfactant is observed 77, 14.2, 2.5 percent by weight.Item Iresine herbstii stem alkaloids as green inhibitor for mild steel corrosion in M H2SO4 solution(2024) Pant, Naresh Prashad; Dr. Deval prasad BhattaraiThe study examined the methanol extract obtained from Irsine herbstii stem as a green inhibitor for mild steel corrosion in a 1M H2S04 environment. Characterization of the extract was carried out using Fourier Transform Infrared Spectroscopy and potentiostat. Additionally, inhibition efficiency was determined through both weight loss and electrochemical measurement methods, with results indicating a maximum inhibition efficiency of 87.28%. Thermodynamic parameters further confirmed the feasibility and spontaneity of the adsorption process. Overall, the findings underscored the potential effectiveness of the inhibitor derived from Irsine herbstii alkoloid extract in mitigating mild steel corrosion in acidic environments.Item Estimation of Copper in Copper Ores Collected from Jangkot Rolpa, Nepal(2024-06) Rajaure, Anil; Dr. Deval Prasad BhattaraiNepal is a country rich in natural resources. There is evidence of the presence of mines of different types of elements, but scientific research in this field is found to be less. Zinc, iron, copper, etc. are the major sources of mines here which have been extracted since time immemorial. But these days, significant research and extraction of such minerals have not been found to occur. In this context, it seems desirable to study and research the mines available in Nepal. In this study, five samples of copper ores were collected from Jangkot Rolpa and examined using Titrimetric analysis, atomic absorption spectroscopy and x-ray diffraction (XRD) methods. The results show that sample C1RJ has the highest copper concentration (2.20% by titration and 1.64% by AAS) among the test samples, indicating that the collected samples contain extractable amounts of copper in that location. The XRD results confirms the ores are auzurite, malachite, cuprite and chalcocite. However, further research is required to carry out the quality of the copper deposit.Item Status of arsenic contamination in the groundwater of nawalparasi west district and Remediation Using ZnCL2 Activated sugarcane bagasse as bioadsorbent(2024-06) Ghimire, Khag Raj; : Dr. Bhoj Raj PoudelGroundwater sources contaminated by arsenic represent a global threat to the environment and living organisms, including humans. Exposure to arsenic for a long period would have a severe health impact. Various conventional techniques are being applied to treat arsenic contaminated water, which are either expensive or less efficient. So, there is a need to develop cost-effective alternative technologies for the removal of arsenic. This research will investigate the possibility of using agro-waste like sugarcane bagasse as a readily available, affordable, eco-friendly bioadsorbent for remediation of toxic pollutants from water. The main target of this study is to develop a novel adsorbent from sugarcane bagasse by ZnCl2 activation. As it is reported that Nawalparasi West district in Lumbini Province has a high concentration of arsenic in ground water, the performance of bio-adsorbent will be examined by 30 different samples from arsenic contaminated area of Nawalparasi. The material which will be developed in this research from sugarcane bagasse is supposed to be efficient and selective for specified arsenic. The batch experiment will be carried out under varying experimental conditions. The kinetics of the adsorption reaction and the adsorption isotherm will be studied. The experimental results will be applied to the treatment of ground water samples from Ramgram municipality, Nawalparasi west district.Item Green synthesis of Silver nanoparticles using Rudraksha extracts:characterization and its applications for antimicrobial activities(Institute of Science & Technology, 2024-06) Jha, Gautam Kumar; Dr. BHOJ RAJ POUDELDifferent methods are reported for synthesis of AgNPs. In this research green synthesis of AgNPs is used as it is simple, economical, environmentally friendly and nontoxic process. Leaves extract of Rudraksha plant has been used for synthesis of AgNPs. Rudraksha and AgNPs both have antimicrobial activity. Green Reduction Ag+ was carried out. Phytochemicals present in leaves extract was studied at room temperature. The Synthesized AgNPs was characterized using techniques UV -visible Spectral analysis, XRD, and FTIR followed by assessment of antimicrobial property against some bacteria and fungus of extract, AgNPs and their composite 1:1 mass ratio. The size of synthesized AgNPs was about 11.93nm. The antimicrobial activity of AgNPs was enhanced by leaf extract of Rudraksha.Item Analisys of Bioactive Phytochemicals and Study of Antimicrobial Activity From Methanolic Extract of Roots of Streptopus streptopoides(Institute of Science & Technology, 2024-06) Subedee, Anup; Dr. Deval prasad BhattaraiTraditional practice of using medicinal plants have been the foundation of modern medicine. Streptopus streptopoides is a plant of traditional medicinal value. This report focuses in the phytochemical analysis of root parts of Streptopus streptopoides collected from Gorkha and study of biological activity of the extract. Methanolic extract of root was used for the analysis. Herein, three hundred grams of dried powder of the root of the plant was processed to extraction using methanol. The extract of S. streptopoides root solution was subjected to primary phytochemical screening. Methanol extract method revealed the presence of various phytochemicals. Total flavonoid content (TFC) in methanol has been reported to be 1.92±0.36 mg QE/g. It indicated the prescence of very low content of flavonoid in the plant sample. The total phenolic content (TPC) in methanol extract has been quantified to be 50.37 ± 0.44 mg GAE/g. Nauplii started dying at the concentration of 50 ppm. 50% (or more) of the tested nauplli died at the highest concentration of 100 ppm. Hence, LC50 of methanol extract is at 100 ppm (100 µg/mL).Item Photocatalytic degradation of commonly used organic dye in Nepal using nanoparticles(Institute of Science & Technology, 2024-04) Shrestha Pradhanang, Situ; Prof. Dr. Rajesh PanditThe utilization of organic dyes across various industries has significantly contributed to the vibrant colors in fabrics, papers, and wools. However, the release of these dyes into water bodies poses a significant environmental challenge due to their persistent nature as pollutants. To address this issue, researchers have been exploring different methods for the removal of dye pollutants from water, with nanoparticles emerging as promising catalysts for degradation processes under light exposure. In this research work, zirconia (ZrO2) and hydroxyapatite (HAp) nanomaterials were investigated as photocatalysts for degrading methylene blue, a prevalent dye in Nepal. Employing an eco-friendly green synthesis route, both nanomaterials were successfully prepared and characterized using techniques such as X-ray diffraction (XRD), Fourier Transmission-Infrared spectroscopy (FT-IR), and UV- Visible spectroscopy. FTIR analysis confirmed the successful green synthesis of zirconia and hydroxyapatite, while XRD results indicated their nanometric size range. The degradation of methylene blue was conducted using the synthesized nanomaterials under sunlight exposure, with degradation efficiency dependent on nanoparticle dosage and dye concentration. Notably, both ZrO2 and HAp nanoparticles exhibited significant efficacy in dye degradation, with ZrO2 demonstrating superior performance at low dye concentrations and HAp exhibiting remarkable effectiveness at higher nanoparticle doses. This research underscores the promising potential of ZrO2 and HAp nanoparticles as efficient catalysts for mitigating organic dye pollution in water bodies, offering a sustainable approach to address this pressing environmental challenge.Item Exploration of Antidiabetic, Antioxidant and Anticancer Potential of Zanthoxylum armatum, Sarcococca wallichii and Sarcococca coriacea from Nepal(Institute of Science & Technology, 2024-01) Baral, Janaki; Dr. Achyut AdhikariThe present research aims to explore the bioactive potential of extracts, fractions, and selected compounds from the plants' Zanthoxylum armatum DC as well as Sarcococca coriacea and Sarcococca wallichii. The extract of Z. armatum fruit pericarp from Pyuthan district was subjected to bioassay-guided isolation, in vivo antidiabetic, in vivo toxicity studies, and anticancer activities. Bioassay-guided isolation from Z. armatum yielded seven compounds: tambulin (1), prudomestin (2), cinnamic acid (3), cinnamic ester (4), isovanillic acid (5), isoquercetin (6), and ducosterol (7). The structures of the compounds were elucidated using mass spectrometry and 1D-and 2D-NMR spectroscopy techniques. Bioactivities including anti-inflammatory, antioxidant, and anticancer properties, were investigated for extracts, fractions, and compounds, particularly focusing on flavonoids 1 and 2 due to their higher yield. Essential oil extraction was carried out using the Clevenger apparatus through hydro-distillation from the fruit pericarp collected from three major commercial sites, and their GCMS analysis was used to examine volatile components and enantiomeric composition. The antioxidant activities, measured using DPPH, showed increasing activities with IC50 values of ethanolic extract 174.00 ± 1.01, methanolic extract 169.85 ± 0.244, Ethylacetate fraction 42.94 ± 1.19, compound 1 and 2 as 32.65 ± 0.31, 26.96 ± 0.19 µg/mL respectively. Likewise the reactive oxygen species inhibition activities was found potent of ethanolic extract (IC50= 20.7 ± 0.4 µg/mL), methanolic extract (IC50= 27.7 ± 0.7 µg/mL), hexane fraction (IC50= 26.3 ± 1.1 µg/mL), ethyl acetate fraction (IC50 =17.8 ± 1.1 µg/mL), and compounds 1 and 2 (IC50= 7.5 ± 0.3 and 1.5 ± 0.3) µg/mL, respectively as compared to standard ibuprofen (IC50= 11.2 ± 1.9 µg/mL). Molecular docking study of compounds 1 and 2 with cyclooxygenase-2 exhibited optimal binding affinity, with binding energies of -8.4 and -8.6 kcal/mol, respectively compared to standard ibuprofen (-7.7 kcal/mol). Drug likeliness and ADMET analyses indicated superior gastrointestinal absorption for compounds 1 and 2 without any discernible toxic effects. Both the extracts’, hexane fraction, and cinnamic acid (3) possess activity against breast cancer cell line (MCF-7) while extract and hexane fraction were also active against cervical cancer HeLa as measured through MTT assay. Compounds 1 and 2 demonstrated the highest insulin secretion activities at 200 mM and 50 mM, respectively at optimal stimulatory glucose (11-25 mM). Molecular docking and simulation studies of compound 2 with an insulin-secreting target were performed and found to be binding with excellent stability. The GC-MS analysis of essential oil indicated linalool as the major constituent. The hexane fraction’s odorant and olfactory sensory molecules exhibited the qualities of a bio-pesticide. Acute toxicity results showed an LD50 value of 565.68 mg/kg body weight in the case of healthy Swiss albino mice and the histopathological studies indicated inflammatory changes and polymorphs in the pancreas and kidney, and liver necrosis in higher doses. The extract was nontoxic to healthy Long Evans Rats. In vivo antidiabetic studies on Long Evans Rats revealed significant results in lowering blood glucose at (p<0.041, p<0.023, and p<0.003) 25 mg/Kg, 50 mg/Kg, and the standard drug respectively. A dose of 25 mg/Kg significantly (p<0.02) increased hepatic glycogen while 50 mg was significant in hyperlipidemia and in increasing HDL. Bioassay-guided isolation of Sarcococca wallichii Staph. dichloromethane fraction yielded four different compounds Na-Methylepipachysamine D (8), taraxerol (9), beta-sitosterol (10), and oleanolic acid (11). Hydro-methanoic extract of S. coriacea leaf Sc-A, steam Sc-S, and chloroform fraction of S. wallichii at pH 7 (Sw-D) were evaluated for various bioassays and found to be good to potent active. Specifically, Sc-A exhibited notable inhibition against digestive enzymes α-glucosidase (IC50= 39.92 ± 2.52 μg/mL) and α-amylase (IC50= 224.3 ± 1.87 μg/mL), while Sw-D inhibited α-amylase (IC50= 2.116 ± 0.058 μg/mL) exceeding the standard acarbose (IC50= 6.18 ± 0.97μg/mL). Furthermore, antioxidant activities were observed in Sc-A (IC50= 24.56±3.3 μg/mL), Sc-S (IC50= 28.90 ± 5.22 μg/mL) and Sw-D (IC50= 53.79 ± 2.50 μg/mL). Cytotoxicity assessment against breast cancer (MCF-7) revealed an (IC50= 11.50 ± 0.50 μg/mL) for a basic fraction (Sc-B) of S. coriacea while its neutral chloroform fraction (Sc-N) exhibited an (IC50 =68.42±5 μg/mL). Anticancer activity against cervical cancer (HeLa) was observed for Sc-B (IC50 =36.33 ± 10) and Sc-N (IC50 =85.5 ± 5). Sc-B also possesses remarkable antibacterial activities against S. aureus, E. coli, Salmonella typhi. यस् विद्यावारीधी सोधकार्र्यको उद्देश्य वनस्पति जान्थोक्साइम आर्माटम डिसि,सार्कोकोका वालिची स्टाफ र सार्कोकोका कोरिएसि हुक एफ मा रहेका जैविक क्रियाशीलता बिषेसगरी एन्टीडाइबेटीक, एन्टीअक्सीडेन्ट र एन्टीक्यान्सर गुणको खोज गर्नु हो। प्युठान जिल्लाबाट संकलन गरिएको बिज निकालिएको टिमुरको दानाबाट मिथानोलिक र इथानोलिक एक्स्ट्रायाक्ट बनाईएको थियो उत्त इथानोलिक एक्स्ट्रायाकलाई बिभिन्न पोलारिटीको रसाइनिक तत्वमा घोलेर बिभाजन गरियो। उक्त बिभाजनबाट बायोएसे निर्देशनमा इथाइलएसिटेट फ्राक्सनको कोलम क्रोम्याटोग्राफी गरी बिभिन्न सात यौगिकहरु प्राप्त भए । ती यौगिकहरु क्रमसः टाम्बुलिन (१), प्रुडोमेस्टिन (२),सिनामिक एसिड (३), सिनामिक एस्टर (४), इसोव्यानिलिक एसिड (५), इसोक्वर्सेटिन (६),र ड्यूकोस्टेरोल(७) रहेका छन् । यी यौगिकहरुको संरचनाहरुलाई मास स्पेक्ट्रौमेट्री र १–डी र २–डी–एनएमआर स्पेक्ट्रोस्कोपी उपकरण द्वारा पत्ता लगाइयको थियो । एक्सट्रयाक्टहरु, भागहरु र फ्लाभोनोइड यौगिकहरु १ र २ को उच्च मात्राको कारणले थप जैव गतिविधिहरु, गरिएको थियो । तीन मुख्य व्यापारिक स्थलहरु म्याग्दी, सुर्खेत, र सल्यानबाट संकलन गरिएको टीमुरको बिज निकालिएको बोक्राबाट तेल निकाल्नका लागि क्लेभेन्जर उपकरणको प्रयोग गरिएको थियो । सो तेलको जीसीएमएसको माध्यमबाट उद्वेगी यौगिकहरु र एनान्सियोमेरिक संरचना परीक्षण गरिएको थियो। डीपीपीएचद्धारा मापन गरिएको एन्टीआँक्सिडेन्ट एक्टिभिटि,क्रमसः एथानोलिक एक्सट्रयाक्ट आइसि फिप्टी भ्यालु १७४.००±१.०१ माइक्रोग्राम प्रति मि.लि., मेथानोलिक एक्सट्रयाक्टको आइसि फिफ्टी भ्यालु १६९.८५ ± ०.२४४ माइक्रोग्राम प्रति मि.लि., इथाइलेसेटेट फ्रायाक्शनको आइसि फिफ्टी भ्यालु ४२.९४± १ माइक्रोग्राम प्रति मि.लि. तथा योगिक १ र २ को आइसी फिफ्टीभ्यालु क्रमस (३२.६५±०.३१, २६.९६ ±०.१९) माइक्रोग्राम प्रति मि.लि. पाईयो । त्यसैगरी, रिएक्टिभ अक्सीजन स्पेसिस (आरओएस्) गतिविधिमा एथानोलिक एक्सट्रयाक्ट प्रवल पाईयो, आइसी फिफ्टी भ्यालु २०.७ ±०.४ माइक्रोग्राम प्रति मि.लि., मेथानोलिक एक्सट्रयाक्टको आइसी फिफ्टी भ्यालु २७.७ ± ०.७ माइक्रोग्राम प्रति मि.लि., हेक्सेन फ्रायाक्शनको आइसी फिफ्टी भ्यालु २६.३ ± १.१ माइक्रोग्राम प्रति मि.लि., इथाइलेसेटेट फ्र्याक्शनको आइसी फिफ्टी भ्यालु १७.८± १.१ माइक्रोग्राम प्रति मि.लि., र सो एक्टीभिटी बढीप्रदर्सन गर्नेहरुमा क्रमस योगिक १ र २ पाईयो आइसी फिफ्टी भ्यालु ७.५±०.३ र १.५± ०.३० माइक्रोग्राम प्रति मि.लि. भने स्टैण्डर्ड आइब्रोफनको आइसी फिफ्टी भ्यालु ११.२ ± १.९ माइक्रोग्राम प्रति मि.लि. थियो। यौगिकहरु १ र २ को साइक्लोआँक्सीजनेज २ (सीओएक्स–२) सँगको मोलेकुलर डोकिङ्ग अध्ययनले श्रेष्ठ बाइनिडङ एफिनिटि पदर्शन गरेकोमा यौगिकहरु १ र २ को बाइन्डिङ ऊर्जा –८.४ र –८.६ किलोक्यालोरिेप्रति मोल देखायको थियो, जवकी आइब्रोफेनको -७.७ किलोक्यालोरी प्रति मोल थियो। ड्रगलाईकलिनेस् र एडमेट बिश्लेषणले पनि यि दुबै यौगिकहरु १ र २ लाई औसधिय तत्वमा सामेल गर्न निर्देसित गरेको थियो। उत्त एक्स्ट्रायकहरु, हेक्सेन बिभाजन र सिनामिक एसिडले (३) स्तनको क्यान्सर (एमसीएफ–७) बिरुद्ध साइटोटोक्सिक गतिबिधि देखाए। एक्स्ट्रायकहरु, र हेक्सेन बिभाजनले गर्भाशयको क्यान्सर (होला) बिरुद्ध पनि राम्रो गतिबिधि देखाए । योग १ र २ ले सिर्स इन्सुलिन सेक्रेसन गतिबिधिहरु २०० मिमो र ५० मिमोमा उत्तम प्रेरित गुल्कोज(११–२५) मिमोमा देखाए । यौगिक २ सँग इन्सुलिन सेक्रेसनको मोलेकुलर डोकिङ र सिमुलेसन अध्ययनले उत्कृष्ट स्थिरतासहित बाइन्डिङ गरेको देखायो । प्रसोधन गरिएको तेलको जीसी–एमयस बिश्लेषणले लिनालुललाई प्रमुख घटकको रुपमा देखाएको थियो । हेक्सेन भागको सुगंध र अणुहरुले बायो–कीटनाशकको गुण प्रदर्शन गरेको थियो। ऐक्युट बिषमता परीक्षणका परिणामले स्वास्थ्य स्विस आल्बिनो माइसहरुमा शरीरभारको ५६५.६८ मिलीग्राम प्रतिकिलोग्रामको एलडीफिफ्टी भ्यालु प्रदर्शन गरेको थियो, र हिस्टोप्यथोलोजिकल अध्यययनले पेनक्रीयाज र कलेजोमा सुजन रहेको तथा कलेजोमा नेक्रोसिस देखाएको थियो । एक्सट्रयाक्टको असर स्वस्थ लङ इभान्स मुसामा देखीएन । लङ इभान्स डाइबेटिक मुसाहरुमा गरेको इन भिभो अध्ययनले २५ मिग्राप्रतिकिलो, ५० मिग्राप्रतिकिलो मिथानोलिक एक्सट्रयाक्ट र स्ट्यान्डर्ड ग्लीकाजाइडले रक्त ग्ल्युकोजमा क्रमसः कमी गरेको थियो (पि < ०.०४१, पि < ०. ०२३, र पि < ०.००३) । २५ मिग्राप्रतिकिलो डोजले हेपाटिक ग्लाइकोजन उच्च परिणाम प्रदर्शन गरेको थियो (पि <०.०२), जवकी ५० मिग्राप्रतिकिलोले हाइपरलिपिडेमिया र एच्.डी.एल.वृद्धिमा प्रमुख भुमिका देखाएको थियो । पूर्वअध्ययनको आधारमा रहेर अनुसन्धान सुचारु गरीएको वनस्पति सार्कोकोका कोरिएसि हुक एफ, र सार्कोकोका वाल्लिची स्टाफ ले उत्कृष्ट गतिबिधिहरु जस्तै एन्टीडायबेटिक, एन्टीआँक्सीडेन्ट, साइटोटोक्सिक र एन्टीब्याक्टीरियल देखाए।सार्कोकोक्सा वालिची स्टाफ डीसिएम भागको कोलम् क्रोमाटोग्राफीद्वारा चार बिभिन्न यौगहरु, एनए-मेथाइलइपिपासस्यामिन डी (८), टारक्सेरोल (९),बेटा-साइटोस्टेरोल (१०), र ओलिएनोलिक एसिड (११) प्रदान गरेको थियो । एस्. कोरिएसि, एस्–ए र एस्– बीएसको पात र डाँठको हाइड्रौ मेथानोइक एक्सट्रयाक्ट र एस् कोरिएसि क्लोरोफर्म फ्राक्सन् पिएच् सात र एस् वालिचिको डीसीएम् फ्राक्सन् (एस् डबलु डि) लाई बिभिन्न गतिबिधिहरुको मापन गर्दा राम्रो तथा उत्कृस्ट देखियो । खासगरी एस्सि ए ले पाचन प्रकृयाको इन्जायम् अल्फाग्ल्यूकोसिडेज बिरुद्ध आईसि फिफ्टी भ्यालु ३९.९२ ± २.५२ माइक्रोग्राम प्रति मि.लि. र एल्फाअमाईलेज बिरुद्ध आईसि फिफ्टी भ्यालु २२४.३ ± १.८७ माइक्रोग्राम प्रति मि.लि. अवरोध देखाए जवकि, एस्डब्लू डीले एल्फाअमाईलेज बिरुद्ध आईसि फिफ्टी भ्यालु २.११६ ± ०.०५८ माइक्रोग्राम प्रति मि.लि. र स्टान्डरड एकारबोजको आईसि फिफ्टी भ्यालु ६.१८ ± ०.९७ माइक्रोग्राम प्रति मि.लि. थियो । एन्टीआँक्सीडेन्ट मापनले देखायको प्रतिफल अनुसार एस्सि ए आईसि फिटि भ्यालु २४.५६±३.३ माइक्रोग्राम प्रति मि.लि एस्सी बिएस आईसि फिफ्टी भ्यालु २८.९० ± ५.२२ माइक्रोग्राम प्रति मि.लि. र एसडब्लु डीले आईसि फिफ्टी भ्यालु ५३.७९ ± २.५० माइक्रोग्राम प्रति मि.लि. मा प्रदर्शन गरेको थियो । स्तनको क्यान्सर (एमसीएफ–७) बिरुद्ध साइटोटोक्सिक अध्ययनले एससी बी भागले आईसि फिफ्टी भ्यालु ११.५० ± ०.५० माइक्रोग्राम प्रति मि.लि. र तत्कालीन न्यूटर्ल क्लोरोफर्म भागले आईसि फिफ्टी भ्यालु ६८.४२±५ माइक्रोग्राम प्रति मि.लि. प्रदर्शन गरेको थियो । गर्भाशयको क्यान्सर (होला) बिरुद्ध को अनुसन्धानले एससी बीको आईसि फिफ्टी भ्यालु ३६.३३ ± १० र एससी एनले आईसि फिफ्टी भ्यालु ८५.५ ±५ प्रदर्शन गरेको थियो । एस. बी. ले राम्रो आन्टिबक्टरियल गतिबिदी देखियो बिशेस गरी बाक्टएरिया अ एस. औरेअस्, ई. कोली, र सल्मोनेल्ल टाईय्फी बक्टएरियाहरुमा ।Item Functionalization of nanocarbons of different dimensionalities and study the physical properties of their nanocomposites with the thermosetting polymer(Institute of Science & Technology, 2024-01) Sonam Tamang; Dr. Sabita ShresthaThe epoxy/nanocarbon (EP/NCs) nanocomposites were prepared by incorporating NCs of different dimensionalities (such as multiwalled carbon nanotubes; MWCNTs (1D), graphite nanoplatelets; GnP (2D) and nanodiamond; ND (0D), aiming at enhancing their physical and electrical properties thus making them useful in various applications. The NCs were functionalized to a different extent and added to the EP matrix. The functionalization of NCs was confirmed by spectroscopic, thermal and diffraction techniques. The prepared nanocomposites were further characterized by different spectroscopic, thermal and microscopic methods. The electrical and surface wetting properties of those materials were discussed in correlation to their morphologies. The chemical modifications of the NCs were confirmed by Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy showing different oxygen containing functional and increased intensity ratio of D and G band value indicating a high degree of graphitization. The increase in interlayer distance was observed after the acid treatment and the thermal degradation of the acid-treated nanocarbons occurred at lower temperatures also evidencing their successful functionalization. The structural and morphological analysis of the nanocomposites confirmed that there was an effective dispersion between the NCs and epoxy (EP) matrix. In addition to this the hydroxyl functional group was also observed in the case of the acid-treated samples of CNTs, microscopic investigations displayed the brittle nature of the neat epoxy and the addition of nanocarbons on epoxy prevented cracks from propagating, increased the area of the fractured surface and provided a high resistance to fracture. The well-dispersed and cluster-free dispersion of CNTs in the EP/pCNT nanocomposite was observed and the pull-out of the CNTs was also witnessed in the epoxy nanocomposites with pristine CNTs. The thermal stability of EP/NCs composites containing separately pristine and acid-treated nanocarbons was improved slightly in the range of 5-13 ℃. The resistivity of EP/pCNT nanocomposites was found to be decreased as high as about 40 times compared to acid-treated nanocomposites. The higher resistivity of Ep/mCNT was attributed to the shortening of CNT length thereby altering its aspect ratio on acid treatment. On the contrary, acid-treated graphite showed as high as about 35 times decrease in resistivity than that of the pristine graphite because of the well dispersion of graphite particles on the EP matrix. However, in terms of surface wetting properties surface modification of NCs enhances hydrophilicity and wettability of EP/NCs nanocomposites प्रस्तुत अनुसन्धान कार्यमा मुलत: विभिन्न आयामिकतायुक्त नानोकार्बनहरु (जस्तै एक आयामिक कार्बन नानोट्यूब, द्वैआयामिक ग्राफाइट नानोप्लेटलेट तथा सुन्यआयामिक नानोडायमंड) लाई एपोक्सी रेजिन नामक थर्मोसेटिङ् पोलिमरसँग बिभिन्न अनुपातमा मिलाएर नानोकम्पोजिटका नमुनाहरु तयार गरि तिनिहरुको भौतिक एवं विद्युतीय लक्षणहरु जस्ता व्यवहारोपयोगी गुणहरुको अध्ययन प्रसतुत गरिएको छ। यसका लागि प्रत्येक नानोकार्बनको सतहमा उपयुक्त विधिद्वारा विभिन्न परिमाणमा रासायनिक क्रियाशिलताको उद्भब गराई त्यासलाई एपोक्सी रेजिन भित्र समानरुपले घुलाइएको थियो। नानोकार्बनको सतहमा आरोपित रासायनिक क्रियाशिलताको पुष्टिका खातिर प्रकाशपटिय (Spectroscopy), तापिय (Thermal) तथा विवर्तन (Diffraction) विधिहरूको सहयोग लिइएको थियो। अनुसन्धान कार्यका दौरान तयार पारिएका नानोकम्पोजिटहरूका विभिन्न गुणहरूको अवलोकनार्थ पनि प्रकाशपटिय, तापिय, विवर्तन तथा सुक्ष्मदर्शक यन्त्रिय विधिहरूको प्रयोग गरिएको थियो। साथै आन्तरिक शुक्ष्म वनोटको आधारमा ति बस्तुहरुका विद्युतीय एवं सतह संबन्धित गुणहरूको व्याख्या गरिएको थियो। नानोकार्बनहरुको सतहमा रासायानिक परिवर्तन भए नभएको फोरिएर ट्रान्स्फर्म ईन्फ्रारेड (FTIR) तथा रमण स्पेक्ट्रोस्कोपीद्वारा निधो गरिएको थियो। त्यसवाट क्रमशः नानोकणिकाको सतहमा विभिन्न अक्सिजनयुक्त प्रतिक्रियात्मक समुहहरु जोडीएका तथा डि (D) र जी (G) ब्याण्डको तिव्रताको अनुपात (जसलाई नानोकणिकाको ग्राफाईटमा रुपान्तरण भएको सुचकको रुपमा लिइन्छ) पनि केही हदसम्म बढेको पाईयो । अम्लसंगको संसर्गपछि नानोकणिकाका आपसि तहहरु विचको दूरीमा वृद्धि भएको तथा तिनिहरुको उच्च तापक्रममा तताउंदा तौल ह्रास हुने तापमानमा पनि गिरावट आएकोवाट ति कणको सतहमा प्रतिक्रियात्माक समुहहरु जोड्ने कार्य सफल भएको निर्क्यौल गरिएको थियो। नानोकम्पोजिटहरूको संरचनात्मक र रुपात्मक विश्लेषण गर्दा एपोक्सि रेजिन थर्मोसेटीङ्ग पोलिमर र नानोकणिकाहरु बीच प्रभावकारी अन्तरवन्धन (intertwine) भएको पुष्टी भयो । यसका साथै नानोकणिकाहरुको अम्लसंग प्रतिकृया गरेपस्चात तिनिहरुको सतहमा हाइड्रोक्सिल समूहहरु पनि जोडीएका तथा सुक्ष्मदर्शक यन्त्रद्वारा गरिएको अध्ययनले विसुध्द एपोक्सि रेजिनले ब्रिटल प्रकृति देखाए पनि नानोकार्वन पोलिमरसंग मिसाए पश्चात यिनीहरुले यान्त्रिक वलद्वारा उत्पन्न हुन सक्ने शुक्ष्मदरार (Microcrack) लाई रोक्ने तथा शक्ति शोषक सतहको क्षेत्रफल बढाएर उक्त पदार्थको तात्कालिक बिघटनलाई प्रतिरोध गर्ने क्षमतालाई समेत बढाएको पाईयो। एक आयामिक नानोकार्वन, कार्बन नानोट्यूब, को पोलिमरको भित्रि आयतनसम्म राम्रोसंग फैलावट भएको तथ्य त्यसको एपोक्सि रेजिनसंगको मिश्रणको शुक्ष्म अध्ययनमा राम्रोसँग देख्न पाईन्छ। साथै शुद्ध अवस्था र अम्लसँग प्रतिक्रिया पस्चात प्राप्त भएको नानोकार्वन प्रयोग गरी तयार गरिएका नानोकम्पोजिटहरूको थर्मल स्थिरतामा ५-१३ ℃ तापक्रमले वृद्धि भएको पाइयो। शुद्ध नानोकार्बन प्रयोग गरी बनाइएको नानोकम्पोजिटहरूको विद्युतीय प्रतिरोधात्मकता अम्लसँग प्रतिक्रिया पश्चात प्राप्त भएको भन्दा लगभग ४० गुणाले कम भएको पाइयो। प्राप्त नतिजाहरुको विश्लेषणबाट यो निस्कर्षमा पुगिन्छ कि नानोकार्वनको अम्लसँग प्रतिक्रिया गराउँदा यीनिहरुको वनोटलाई खन्डित भई आस्पेक्ट अनुपात परिवर्तन हुन्छ र कम्पोजिटको विद्युतीय गुणमा नकारात्मक असर गर्दछ। यसको विपरीत अम्लसँग प्रतिक्रिया गरेका द्वैआयामिक नानोकार्वन (जस्तै ग्राफाइट नानोप्लेटलेट) एपोक्सि रेजिनसंग राम्रोसँग फैलिएर बनेको हुनाले नानोकम्पोजिटको विद्युतीय प्रतिरोधात्मकता शुद्ध अवस्थाको नानोकार्वन भएको नानोकम्पोजिटको तुलनामा लगभग ३५ गुणाले कम भएको देखियो। नानोकम्पोजिटहरूले आफ्नो सतहमा जलाकर्षण गर्ने गुणहरुलाई केलाउने क्रममा भने रासायानिक रुपमा परिमार्जीत तीनै प्रकारका सूक्ष्म कणहरुले सकारात्मक भूमिका खेलेको पाईयो।Item Chemical Characterization, Enantiomeric Distribution, and Bioactivity Analysis of Essential Oil from the Selected Lamiaceae Plants of Nepal and Their Application in Topical Formulation(Department of Chemical Science and Engineering School of Science Kathmandu University, 2023-12) Prem Narayan Paudel; Prof. Dr. Rajendra Gyawali ; SupervisorEssential oils (EOs) are complex mixtures of biologically active volatile compounds that have been utilized for a long time as flavoring agents, preservatives, and natural ingredients in many commercial products. In recent years, they have drawn great attention due to their increasing demand for food, cosmetics, and pharmaceuticals. Since many studies have revealed the good antimicrobial, antioxidant, and toxicity activities of essential oils, it is very important to characterize them based on their chemical profiles. In the present study, some selective plants from the Lamiaceae family of Nepal were collected to determine the chemical composition, enantiomeric distribution, and biological activities. The hydro-distilled essential oils were characterized for volatile compounds by Gas Chromatography and Mass Spectrometry (GC-MS), GC-Flame Ionization Detection (GC-FID), and enantiomeric composition by Chiral GC-MS. The chemometric analysis was applied to identify the chemotaxonomic relationship among Lamiaceae essential oils. The antimicrobial property was evaluated by the microbroth dilution method using some ATCC bacterial and fungal strains. The antioxidant activity was determined by DPPH and ABTS radical-scavenging assays. The in vitro cytotoxicity was evaluated in human breast cancer (MCF-7) and fibroblast (NIH-3T3) cell lines by using the Cell Counting Kit-8 kit assay. The antioxidant-rich essential oils were blended into the cream formulation. The results revealed the variation in the yield of essential oils with harvesting seasons. The species showed higher essential oil yield in the summer season and tropical regions than others. Ocimum tenuiflorum L. had the highest concentration (1.68±0.13%), and Leucosceptrum canum Sm. had the lowest yield among the samples (0.15±0.05%). The average essential oil yield obtained from the Lamiaceae plant species in Nepal was about 0.76%. Oxygenated monoterpenes were the dominant class of terpenoids present in most of the essential oil samples, with concentrations above 49%. Mentha pulegium L. showed the highest proportion of oxygenated monoterpenes (91.63%), followed by Mentha spicata L. (85.3%) and Perilla frutescens (L.) (83.05%). The lowest yield of oxygenated monoterpenes was found in Colebrookea oppositifolia Sm. at 0.89%. The single compound, carvone, was detected in the highest concentration for Mentha spicata L. oil (68.51%). The seasonal variations in the chemical composition of essential oils were also detected among the Lamiaceae samples. Origanum majorana L. comprises linalool and terpinen-4-ol as major compounds, with 13.8% and 32.1% in spring, and 15.37% and 33.35% in summer. Similarly, the carvone of M. spicata L. was not much influenced by seasonal variation, with 51.96% in winter and 68.51% in summer. Major constituents of O. tenuiflorum L., eugenol (32.15 to 34.95%), and trans-β-elemene (29.08 to 32.85%) were not much influenced by seasonal variation except minor ones. The same result was also detected in O. basilicum L., where methyl chavicol (62.16–64.42%) and linalool (26.92–27.09%) were not variable during the winter and summer seasons. A minor seasonal variation in the major compounds was observed for M. pulegium L. In contrast, the major constituents of L. canum Sm. were highly influenced by seasonal variations. The leading compound, β-pinene, of L. canum Sm. was found at 29.07% in winter, which decreased to 15.21% during summer. Similarly, another leading compound, β-caryophyllene, of L. canum Sm. was found at 13.29% in winter, which increased to 33.51% during summer, thereby indicating the seasonal variation in the chemical composition of Lamiaceae essential oils. In the chemometric analysis, agglomerative hierarchical cluster analysis for Lamiaceae essential oil showed two main groups of volatile classes: the first dominated by oxygenated monoterpenes and the second by sesquiterpene hydrocarbons. Both principal component analysis and clustered heat maps confirmed the two distinct groups of volatile components as assigned by HCA. The chiral GC-MS revealed several chiral compounds in the essential oil samples. The α-thujene, αpinene, sabinene, β-pinene, camphene, limonene, 1-octen-3-ol, linalool, α-terpineol, cis-sabinene hydrate, menthone, β-caryophyllene, terpinen-4-ol, germacrene D, borneol, β-bisabolene, δcadinene, (E)-β-ionone, and (E)-nerolodol were common chiral compounds in the EO, dominating in the levorotatory form (62.4%). In the DPPH assay, O. tenuiflorum L. exhibited relatively good antioxidant activity (IC50 69.2382.99 µg/mL), when compared to the standards (ascorbic acid, IC50 6.37 µg/mL and BHT, IC50 12.46 µg/mL), and in the ABTS aasay, this essential oil exhibited the strongest activity (IC50 5.88-17.69 µg/mL), when compared to the standards (ascorbic acid, IC50 1.98µg/mL and quercetin, IC50 7.79 µg/mL). The least activity was noted in M. pulegium L. from Nuwakot during the summer with an IC50 value of 646.58 µg/mL in the DPPH assay and with an IC50 value of 145.35 µg/mL in the ABTS assay. The antioxidant activity M. spicata L., P. frutescens (L.), L. canum Sm., and O. majorana L. The essential oils obtained in the summer was higher as compared to the essential oils collected during the winter. In contrast, O. ameicanum L., O.ameicanum L., O. basilicum L., and O. tenuiflorum L. The essential oils collected during winter exhibited higher antioxidant activity than those from the summer. The present study also revealed that the seasons and environmental conditions may influence the photochemistry of plants, thereby affecting their antioxidant properties. Samples from tropical zones had better antioxidant activities than the other parts. The effect of these essential oil samples on the viability of human breast cancer (MCF-7) and fibroblast NIH-3T3 cell lines was also found to be significant. Among the Lamiaceae essential oils, P. frutescens (L.) (IC50 7.41 and 8.14 µg/mL), C. umbrosum (M. Bieb.) C. Koch (IC50 21.70 and 12.53 µg/mL), M. longifolia L. (IC50 23.76 and 12.12 µg/mL), and O. tenuiflorum L. (23.43 µg/mL) samples were highly cytotoxic as compared to other species against both cell lines. While M. pulegium L., M. spicta L., P. glabar Benth., and O. basilicum L. essential oils displayed the least toxicity, with the IC50 values varying from 99.64 to 90.56 µg/mL. Among the essential oil studied against fungal strains, O. majorana L., M. pulegium L., and O. tenuiflorum L. were more effective against Candida albicans and Aspergillus niger (MIC, 78.1 µg/mL). O. majorana L. essential oil exhibited a broad spectrum of antimicrobial activity, with a MIC value of at least 156.3 to 312.5 µg/mL for all tested organisms. For anti-bacterial activity, only slight inhibition of these oils was found against all the tested bacterial strains. Similarly, the essential oils of O. majorana L., O. tenuiflorum L., and O. basilicum L. were utilized for the formulation of cream, which showed the retention of their best efficacy after extensive investigation of several pharmacological parameters. Hence, the present study concluded that the chemotaxonomic profiles of many essential oil samples from the Lamiaceae family of Nepal were prepared. They also exhibited excellent and varied biological efficacies, which can be useful in bioprospecting for the benefit of human health. Keywords: Lamiaceae, Essential Oil, GC-MS, Chemical Composition, Enantiomer, Antioxidant, Antimicrobial, Cytotoxicity, Formulation.Item Characterization of the Cellulosic Fiber Obtained from Nepalese Lokta Bushes and Explore its Novel Applications(Institute of Science and Technology, 2024-05) Aryal , Girja ManiIn Nepal, Handmade papers (HPs) are made from fibrous biomass of several plant species. Paper fabricated from fibrous biomass obtained from Lokta bushes following the traditional eco-friendly method is called Lokta paper or Nepal Kagaj. Handmade paper fabricated from Lokta bushes is being used to fabricate value-added products. The paper is traditionally believed to be durable and bug and mold-resistant. However, a systematic study on the material properties of this paper is not reported yet. Additionally, material properties of Lokta fiber retted under different conditions; which help to understand the performance of Lokta fiber-derived products is not mentioned in the literature. To increase, trade value it is also equally important to find next generation applications of the Lokta paper. This dissertation work was aimed at understanding the material properties of Lokta paper and fiber, and the fabrication of Lokta paper-derived nanocomposite mat for antimicrobial application. It was found that the mean caliper, apparent density, Cobb 60, grammage, brightness, opacity equilibrium moisture content, tensile strength, and tensile index values in the paper samples collected from local enterprises (n=10) ranged from ~90‒700µm, 0.2‒0.4 g/cm3, 50‒150 g/m2, 4‒7%, 50‒400 g/m2, 56‒67 %, 83‒98 %, 30‒2900 N/m, and 1‒27 Nm/g; in that order. These data recommended that Lokta paper is a light weight paper having intermediate to high strength, high caliper variation and relatively low brightness. All paper samples exhibited considerably increased tensile strength across the length axis (p<0.05). Distinctive characteristics of hemi‒cellulose, cellulose, and lignin were spotted in the FTIR spectra of all the samples. The amorphous and crystalline cellulosic segments were detected in X‒ray diffraction (XRD) data. Most importantly, electron microscopic showed a properly cross-linked web of entire fibers organizing a parallel layout of microfibrils. These morphological qualities could be responsible for delivering strength and durability to the paper samples. A comprehensive analysis of material properties of Lokta fiber subjected to 1-9% NaOH (w/v) concentrations at ambient temperature was also performed. The alkali resulted in significant shrinkage of lignin and hemicellulose; thereby increasing the cellulose content. On alkali treatment, fiber width and equilibrium moisture content decreased whilst fiber density, crystallinity index, tensile strength, and thermal stability increased. These changes can be assigned to the deduction of cementing materials from fiber bundles. These findings suggested that processing conditions greatly affect the fiber properties and to get Lokta paper of optical performance fiber chemistry needs to be properly tailored. Finally, Lokta paper-making process was mimicked in laboratory settings and the physico-chemical properties of lab-made Loka paper were compared with commercially available paper. The Ag/ZnO and Cu nanoparticles were doped in the Lokta paper following hydrothermal and chemical reduction methods. The Lokta paper nanocomposite mat showed promising antimicrobial activity contrary to two bacteria (Escherichia coli and Bacillus subtilis) and a fungal strain (Candida Albicans). These observations suggested that the Lokta paper-derived nanocomposite mat can find potential applications as an antimicrobial packaging material.Item Preparation of amperometric glucose biosensor by means of electropolymerisation of polyaniline onto graphite(Department of Chemistry, 2013) Bhusal, Suresh PrasadIn this study, an amperometric glucose biosensor with immobilization of glucose oxidase enzyme on electrochemically polymerized polyaniline film onto graphite surface has been prepared. The immobilization of the enzyme glucose oxidase has been accomplished via the physical entrapment technique. Electropolymerization of aniline onto the suface of the graphite was carried out by cyclic voltammetry (potential range of -0.4V to 1.2V, scan rate 100mV/sec, 10 cycles) by using standard calomel electrode (SCE) as reference and platinum wire as counter. Characterization of the PANi/Graphite was carried out with the aid of cyclic voltammetry in 1M HCl, obtaining three couple of peaks from which the two pair were distinct, having proved the electro-activity of the PANi film. The enzyme was potentiostatically immobilized onto the surface from 0.1M phosphate buffer of pH 6.0 with 200U/mL glucose oxidase (GOx) enzyme. The amperometric response was studied by using hydrodynamic amperometric mode. Determination of glucose was carried out by the measurement of amperometric response obtained during the reduction of enzymatically produced hydrogen peroxide at - 0.4 V vs calomel electrode and platinum wire as counter in phosphate buffer of pH 6.0. Biosensor was found to be responsive within the concentration range of 0.01ML -1 -0.1ML -1 . All experiments were carried out at room temperature.Item Synthesis, Characterization, and Antibacterial Evaluation of Metal Complexes of Surfactant Based Schiff Bases(Institute of Science & Technology, 2024-03) Adhikari, JanakModern pharmaceutical science needs more efficient drug delivery systems (DDSs) that permit poorly aqueous soluble drugs to work effectively. Consequently, medications function effectively. Pharmacological science has found Surfactants to be an invaluable alternative for enhancing the potential of conventional drugs and improving the efficacy of drugs with poor water solubility. Solid drugs can be solubilized more easily when surfactant molecules are added and membrane permeability can be increased in lipid layers as a result. In the last few years, the synthesis of transition metal complexes of Schiff bases has drawn a lot of interest as an alternative to coordination compounds for the creation of chelating agents. Metal chelates have suitable biological activities. This research aims to design and develop surfactant-containing Schiff bases and their metal complexes, which can serve as a drug to solve the problems with antibiotic resistance and drug delivery. The study has focused on the structural modification of compounds under study (Pyrrole-2-carboxaldehyde, Pyrrole-3-carboxaldehyde, and Dodecylamine) by forming the Schiff bases and metal complexes and their correlation with bio-functional activities. Given this, two new Schiff bases [DDAP2C and HL (DDAP3C)] have been prepared and further complexed with four transition metal ions, Co2+, Ni2+, Cu2+, and Zn2+. The newly prepared metal complexes and Schiff bases were fully characterized by elemental microanalysis, conductivity measurement, melting point measurement, 1HNMR, 13CNMR, FT-IR, UV/Vis, ESI-mass, MALDI-TOF-mass spectrometry, and magnetic susceptibility, studies. The conductivity data were used to calculate the synthesized compounds' critical micelle concentration (CMC), which was further utilized to derive the Gibbs free energy of micellization (ΔG°m). Thermal stability and kinetic properties of the complexes were determined using thermogravimetric and differential thermal analysis (TGA/DTA). The Coats-Redfern method was used to extract thermodynamic parameters that describe the kinetic activity of the complexes. Most complexes showed high thermal stability and non-spontaneous decomposition steps. The powder X-ray diffraction study was conducted to verify the crystalline nature of the complexes. The Origin and X'pert high score software were used to analyze PXRD data, and the diffractograms were carefully analyzed to get information about the nature of complexes. Most of the complexes were found to crystalline with nanocrystalline size. Scanning electron microscopy (SEM) studies enabled the characterization of the surface morphology of Schiff bases and complexes and revealed their different surface textures. Molecular modeling has provided additional support for the geometry of the complexes determined by spectroscopic methods. The structure optimization was achieved by running the proposed molecular structures in CsChemOffice Ultra 16 and Argus Lab 4.0.1 software with MM force field calculation. The standard Kirby-Bauer paper disk diffusion technique demonstrated the antibacterial potency of the Schiff bases and metal complexes. Several clinical strains of both gram-positive and gram-negative bacteria have been isolated and cultured in laboratories to achieve this objective. They have interacted with synthesized complexes solution prepared in DMSO at variable concentrations. These were further quantified more precisely by performing a minimum inhibitory concentration (MIC) test. In most biological studies, the free Schiff bases and compounds under study were found to have lower antibacterial efficacy than the Schiff base metal complexes. The copper complexes of both the Schiff bases showed excellent antibacterial activity. आधुनिक औषधि विज्ञानलाई अझ प्रभावकारी औषधि वितरण प्रणालीको आवश्यकता छ, जसको उपलब्धताले खराब जलीय घुलनशील औषधिलाई पनि प्रभावकारी रुपमा कार्य गर्ने बाटो खुल्न जान्छ। परिणामस्वरुप औषधिहरूले अझ प्रभावकारी ढंगले आफ्नो कार्य सम्पादन गर्दछन्। फार्माकोलोजिकल विज्ञानले परम्परागत औषधिहरूको प्रभावकारीता बढाउन, खराब जलीय घुलनशिलता एवम् औषधिहरूको प्रभावकारीतामा सुधार गर्न सर्फेक्टेन्टहरूलाई अमूल्य विकल्प को रुपमा पहिचान गरेको छ। जब औषधिहरूमा सर्फेक्टेन्ट अणुहरू थपिन्छ, ठोश औषधिहरूको घुलनशिलतामा बृध्दि हुन जान्छ फलस्वरुप लिपिड तहहरुमा झिल्ली पारगम्यता बढ्न गई औषधिहरूको प्रभावकारीता बढ्न जान्छ। पछिल्ला केही वर्षहरुमा शिफ बेशहरुबाट धातु कमप्लेक्सहरुको सश्लेषण हुने तथ्यले चेलेटिंग एजेन्टहरूको सिर्जनाको लागि समन्वय यौगिकहरुको विकल्पको रुपमा अधिक ध्यान आकर्षण गरेको छ। धातु चेलेटहरुमा उपयुक्त जैविक गतिविधिहरु विद्यमान हुन्छन्। यस अनुसन्धानले सर्फेक्टेन्ट्युक्त शिफ बेशहरु र तिनीहरुका धातु कमप्लेक्सहरुका डिजाइन र विकाश गर्ने लक्ष्य राखेको छ, जसले एन्टिवायोटिक प्रतिरोध र औषधि वितरणको समस्याहरु समाधान हेतु औषधिको रुपमा कार्य सम्पादन गर्न सक्छन्। यो अध्ययनले शिफ बेशहरु र धातु कमप्लेक्सहरु निर्माण पश्चात, अध्ययनमा लिइएका यौगिकहरुको संरचनात्मक परिमार्जन र जैविक-कार्यात्मक गतिविधिहरुसँग तिनीहरुको अन्तर सम्बन्धका बारेमा ध्यान केन्द्रित गरेको छ। यस तथ्यलाई हृदयङ्गम गर्दै, दुई नयाँ शिफ बेशहरु तयार गरी, तिनीहरुको चार धातु आयनहरुसँग (Co2+, Ni2+, Cu2+, & Zn2+) थप धातु कमप्लेक्सहरु बनाइएको छ। नयाँ तयार गरिएका शिफ बेशहरु र धातु कमप्लेक्सहरुलाई सम्पूर्ण रुपमा Elemental microanalysis, चालकता मापन, पग्लने बिन्दु मापन, 1HNMR, 13CNMR, FT-IR, UV-Vis, ESI-mass, MALDI-TOF-mass Spectrometry र चुम्बकीय संवेदनशीलता अध्ययनहरु द्वारा चरित्र चित्रण गरिएको थियो। चालकता तथ्याङ्क सश्लेषित यौगिकहरुको महत्वपूर्ण मिसेलि एकाग्रता (CMC) को गणनाको लागि प्रयोग गरिएको थियो, जुन गिब्स फ्री एनर्जी अफ माइसलाइजेशन (ΔG°m) प्राप्त गर्न पुन: प्रयोग गरिएको थियो। थर्मोग्राभीमेट्रिक र विभेदक थर्मल विश्लेषण प्रयोग गरेर तापीय स्थिरता र कमप्लेक्सहरुको गति सम्बन्धित गुणहरु निर्धारण गरिएको थियो। कोट्स-रेडफर्न (Coats-Redfern) विधि प्रयोग गरी थर्मोडायानामिक प्यारामिटरहरु निकालिएको थियो, जसले कमप्लेक्सहरुको काइनेटिक गतिविधि वर्णन गर्दछन् । धातु कमप्लेक्सहरुले उच्च तापीय स्थिरता र गैर-स्वस्फूर्त विघटन चरणहरु देखाएका थिए। पाउडर एक्सरे विवर्तन (PXRD) अध्ययन, कमप्लेक्सहरुको क्रिस्टलीय प्रकृति प्रमाणित गर्न प्रयोग गरिएको थियो। Origin र X’ Pert High Score Software हरु प्रयोग गरी PXRD तथ्याङ्कहरुको विश्लेषण गरिएको थियो र कमप्लेक्सहरुको प्रकृतिबारे जानकारी प्राप्त गर्न तिनीहरुको Diffractograms हरुलाई सावधानीपूर्वक विश्लेषण गरिएको थियो। कमप्लेक्सहरु नैनोक्रिस्टलाइन प्रकृतिका थिए। स्क्यानिङ्ग इलेक्ट्रोन माइक्रोस्कोपी (SEM) अध्ययनद्वारा शिफ बेशहरु र कमप्लेक्सहरुको सतह उजागर गरिएको थियो र तिनीहरुको विभिन्न सतहगत बनावट पाइएको थियो। आणविक मोडेलिंगले, स्पेक्ट्रोस्कोपिक विधिद्वारा निर्धारित कमप्लेक्सहरुको ज्यामितीको लागि अतिरिक्त समर्थन प्रदान गरेको छ। CsChem Office Ultra 16 र Argus Lab 4.0.1 Software मा MM Force field गणनाको साथै प्रस्तावित आणविक संरचनाहरुलाई चलाएर, संरचना अनुकूलन हासिल गरिएको थियो। मानक किर्बी-बाउर पेपर डिस्क प्रसारण प्रविधिले शिफ बेश र धातु कमप्लेक्सहरुको जीवाणुरोधी शक्ति प्रदर्शन गरिएको थियो। यो उदेश्य हासिल गर्न प्रयोगशालामा ग्राम-पजिटिभ र ग्राम-नेगेटिभ व्याक्टेरियाका धेरै क्लिनिकल स्ट्रेनहरुलाई पृथकीकरण एवम् संवर्धन गरिएको थियो। तिनीहरुले विभिन्न एकाग्रता का DMSO मा तयार गरिएको सश्लेषित यौगिकहरुको घोलसँग अन्तरक्रिया गरेका थिए। सश्लेषित यौगिकहरु को जीवाणुरोधी सक्रियता थप सटिक रुपमा न्यूनतम अवरोध एकाग्रता (MIC) परीक्षण गरेर प्रमाणित गरिएको थियो। जैविक अध्ययनहरुमा, अध्ययन अन्तर्गतका यौगिकहरु र शिफ बेशहरु, तिनीहरुका धातु कमप्लेक्सहरुभन्दा कम जीवाणुरोधी क्षमताका पाइएका थिए।Item Corrosion behavior of sputter-deposited W-Mo alloys in NaOH solutions(Department of Chemistry, 2010) Khadka, ArunThe corrosion behavior of the sputter-deposited nanocrystalline WMo alloys is studied after immersion for 24-29 h in different concentrations of NaOH solutions at 25 o C, open to air by using corrosion tests and open circuit potential measurements. Molybdenum metal acts synergistically with tungsten in enhancing the corrosion resistance of the sputter-deposited W-Mo alloys so as to show the lower corrosion rates than those of alloyconstituting elements (that is, tungsten and molybdenum) after immersion for 24-29 h in NaOH solutions. In general, the open circuit potentials of all the examined W-Mo alloys are shifted to the more positive (noble) direction with increasing the molybdenum content in the alloys. The stability of the spontaneous passive films of the binary W-Mo alloys is decreased with increasing the concentrations of NaOH solutions. However, the corrosion rates of all the examined W-Mo alloys are almost independent of concentrations of NaOH solutions (that is, 0.01 M, 0.1 M and 1 M NaOH).Item Synthesis, Characterization, and Biological Investigations of Heteroleptic Complexes of Tetracyclines and Salicylaldehyde Mixed Ligands(Institute of Science & Technology, 2024-02) Dev, Rohit KumarToday, the resistance of bacteria is due to their misuse and overdose of antibiotics. Therefore, researchers are working day and night to discover new antibiotics that can solve the challenges of multi-drug resistance. The present study describes the synthesis of the metal complexes with the help of the primary ligand, tetracycline/oxytetracycline (TC/OTC), secondary ligand, salicylaldehyde (Sal), and 4d-transition metal salts [M=Cd(II), Zr(II), Mo(III)/ Mo(V), and Pd(II)]. A calculated amount of eqimolar mixture of primary ligand (TC) is dissolved in 70 % ethanol and stirred under magnetic stirrer. A stirred aqueous solution of metal salt is added dropwise to the TC solution. The stirred alcoholic solution of the secondary ligand (Sal) is also added to the above reaction mixture dropwise and refluxed in a reflux condenser. The pH is maintained by the adding ammonia solution resulting the formation of precipitate. The dried precipitate is recrystallized to obtain the amorphous form of metal complex. Furthermore, the complexes were analyzed using physical and spectral techniques. Here, the physical method includes elemental microanalysis, pH, specific conductivity, viscosity, surface tension, density, and melting point measurements. Similarly, the spectroscopic method includes FT-IR, (1H and 13C)- NMR, UV/Visible, and ESI-MS spectrometry techniques. The results obtained from the conductivity data showed both electrolytic and non-electrolytic nature, which indicates that the metal complexes are correlatively bonded to the metal ions. Also, the findings from the UV/Vis. spectra confirmed the proposed structure as well as the geometry of the metal complex. The thermal and kinetic stability of the complex was obtained from thermo gravimetric and differential thermal analysis (TGA/DTA) techniques. The thermodynamic parameters of various decomposition steps, ∆S*, ∆H*, ∆G*, E*, A, T, can be calculated from the well-known popular Coats- Redfern equation. The results obtained from the thermal data show that the complexes have high thermal stability and also non-spontaneous nature during different decomposition steps. The spectral studies of metal complexes showed better results with the molecular formula. The SEM (Scanning electron microscope) determines the surface morphology of the compound. The complexes were further supported by the information obtained from 3D molecular modeling viz: Chem 3D pro 12.0.2 software program, which provided the theoretical predictions of the metal complexes and a better and more accurate evaluation of the proposed structure. Using the MM2 calculations, the energy optimization was repeated several times to note the minimum energy. The difference in M-N and M-O values indicates the coordination of metal ions with the ligand. The metal complex was tested for in vitro antibacterial susceptibility by two strains of human clinical pathogenic bacteria: Staphylococcus aureus (gram-positive) and Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa (gram-negative). The tests were performed with the help of the well-known modified Kirby-Bauer paper disc diffusion method. Antimicrobial study results showed better results at higher concentrations and considerable activity at lower concentrations. The zone of inhibition was measured in diameter (mm) with the help of an antibiogram zone measuring scale. Here, all clinical pathogens were found to be more susceptible to the prepared derivatives of TCs. The antibacterial potency is based on the concept of Overton’s and Tweedy’s chelation principle which is related to the stability and easy permeation of the lipid layer of the organism by metal complexes. आज, ब्याक्टेरियाहरूको प्रतिरोध उनीहरूको दुरुपयोग र एन्टिबायोटिकको अधिक मात्राको कारण हो। तसर्थ, अनुसन्धानकर्ताहरू बहु-औषधि प्रतिरोधका चुनौतीहरू समाधान गर्न सक्ने नयाँ एन्टिबायोटिकहरू पत्ता लगाउन दिनरात काम गरिरहेका छन्। हालको अध्ययनले प्राइमरी लिगान्ड, Tetracycline/Oxytetracycline (TC वा OTC), सेकेन्डरी लिगान्ड, Salicylaldehyde (Sal), र 4d-ट्रान्जिसन धातु लवणहरु [M=Cd(II), Zr(II), Mo(III)/(V), र Pd(II)] को मद्दतबाट धातु कम्प्लेक्सहरुको निर्माण गर्ने बारे बर्णन गर्दछ। प्राइमरी लिगान्ड (TC)/(OTC) को समान मोलर (molar) मिश्रणको गणना गरिएको मात्रा, 70% इथेनोलमा घुलाए पछि चुम्बकीय स्टिरर् द्वारा चलाईएको थियो। धातुको लवणको चलाईएको जलीय घोल TC को घोलमा थोपा-थोपा गरेर थपिएको थियो। सेकेन्डरी लिगान्ड (Sal) को चलाईएको अल्कोहलयुक्त घोल पनि माथिको प्रतिक्रिया मिश्रणमा थोपा-थोपा गरेर थपिएपछि रिफ्लक्स कन्डेनसरमा रिफ्लक्स गरिएको थियो। अमोनिया घोल थपेर पीएच (pH) मिलाएको परिणामस्वरूप धातु कम्प्लेक्सको गठन भएको थियो। धातु कम्प्लेक्सको घोललाई सुकाएर प्राप्त ठोसलाई शुध्द बनाउन पुन क्रिस्टलिकरण गरिएको थियो। यसपछि, कम्प्लेक्सहरूलाई भौतिक र वर्णक्रमीय प्रविधिहरू प्रयोग गरेर विश्लेषण गरिएको थियो। जसमा, भौतिक विधिमा मौलिक सूक्ष्म विश्लेषण, pH, विशिष्ट चालकता (Specific conductivity), भिस्कोसिटी (viscocity), सतह तनाव (surface tension), घनत्व (density), र पिघलने बिन्दु मापन (Melting point measurement) लगायतका समावेस छन्। त्यस्तै, स्पेक्ट्रोस्कोपिक विधिमा FT-IR, (1H र 13C)- NMR, UV/visible, र ESI-MS स्पेक्ट्रोमेट्री प्रविधिहरू समावेश छन्। चालकता डेटाबाट प्राप्त नतिजाहरूले धातु कम्प्लेक्सहरु इलेक्ट्रोलाइटिक र गैर-इलेक्ट्रोलाइटिक दुवै प्रकृतिका देखिएका थिए, जसले धातु कम्प्लेक्सहरू धातु आयनहरूसँग सहबद्ध रूपमा बाँधिएको संकेत गर्दछ। साथै, UV/Vis स्पेक्ट्राको निष्कर्षहरूले धातु कम्प्लेक्सहरुको प्रस्तावित संरचना र ज्यामितिलाई पुष्टि गर्दछ। कम्प्लेक्सको थर्मल र काइनेटिक स्थिरता थर्मो ग्रेभिमेट्रिक र विभेदक थर्मल विश्लेषण (TGA/DTA) प्रविधिहरूबाट प्राप्त गरिएको थियो। विभिन्न विघटन चरणहरूको थर्मोडायनामिक मापदण्डहरू, ∆S*, ∆H*, ∆G*, E*, A, T, प्रसिद्ध लोकप्रिय कोट्स- रेडफर्न समीकरणबाट गणना गरिएको थियो। थर्मल डाटाबाट प्राप्त नतिजाहरूले देखाउँछन् कि कम्प्लेक्सहरूमा उच्च थर्मल स्थिरता र विभिन्न विघटन चरणहरूमा गैर-स्वस्फूर्त प्रकृतिका थिए। धातु कम्प्लेक्सको वर्णक्रमीय अध्ययनले आणविक सूत्र अनुरुपको परिणाम देखाएको थियो। SEM (स्क्यानिङ इलेक्ट्रोन माइक्रोस्कोप) अध्ययनद्वारा यौगिकको सतह आकारविज्ञान निर्धारण गरिएको थियो। कम्प्लेक्सहरूको संरचनाहरुलाई 3D आणविक मोडेलिङ जस्तै: Chem 3D प्रो 12.0.2 सफ्टवेयर प्रोग्रामबाट प्राप्त जानकारीद्वारा समर्थन गरिएको थियो, जसले धातु कम्प्लेक्सहरूको सैद्धान्तिक भविष्यवाणीहरू र प्रस्तावित संरचनाको राम्रो र सटीक मूल्याङ्कन गरेको थियो। MM2 गणनाहरू प्रयोग गरेर, न्यूनतम ऊर्जा प्राप्त गर्न ऊर्जा अनुकूलनलाई धेरै पटक दोहोर्याइएको थियो। M-N र M-O मानहरूमा भिन्नताले लिगान्डसँग धातु आयनहरूको समन्वयलाई संकेत गर्दछ। धातु कम्प्लेक्सहरूलाई मानव रोगजनक ब्याक्टेरियाका दुई प्रकारहरूद्वारा इनभिट्रो एन्टिब्याक्टेरियल संवेदनशीलताको लागि परीक्षण गरिएको थियो; जसमा, स्टेफिलोकोकस ऑरियस (ग्राम- पोजिटिभ) र क्लेब्सिएला निमोनिया, एस्चेरिचिया कोलाई, प्रोटस मिराबिलिस, र स्यूडोमोनास एरुगिनोसा (ग्राम-नेगेटिभ) ब्याक्टेरियाहरू समाबेश गरिएको थियो। प्रख्यात परिमार्जित किर्बी-बाउर पेपर डिस्क प्रसार विधिद्वारा परिक्षणहरु गरिएको थियो। एन्टिमाइक्रोबियल अध्ययन परिणामहरूले उच्च सांद्रतामा राम्रो नतिजा र कम सांद्रतामा उल्लेखनीय गतिविधि देखाएका थिए। एन्टिबायोग्राम जोन मापन स्केलको मद्दतले अवरोधको क्षेत्रको व्यास (मिमी) नापिएको थियो। यहाँ, सबै प्याथोजेनहरू TCs को तयार डेरिभेटिभहरूमा बढी संवेदनशील भएको पाइयो। जीवाणुरोधी क्षमता ओभरटन र ट्वीडीको चेलेसन सिद्धान्तको अवधारणामा आधारित छ जुन धातुको कम्प्लेक्सहरूद्वारा जीवको लिपिड तहको सहज पारगमनसँग सम्बन्धित छ।Item Investigation of Soil corrosion to buried metallic materials of Kathmandu Valley, Nepal(Institute of Science & Technology, 2023-10) Dahal, Kumar PrasadMetallic pipes have been utilized for long times to distribute potable water from distribution terminals to the consumers in urban cities of Nepal. However, large amounts of such potable water have been lost due to corrosion damage of such underground pipes. It is an urgent need to know the main responsible factors for such buried metallic pipeline failures, and subsequently evaluate the level of corrosion risk in the soils of Kathmandu Valley. Six soil factors (pH, moisture, resistivity, oxidation-reduction potential, chloride ion and sulfate ions) of 150 soil samples were determined using ASTM, NACE, AASHTO, and AWWA standards, The soils of Kathmandu Valley could be rated as mildly corrosive to less corrosive groups. A good positive and negative correlation coefficient between resistivity, moisture, chloride, and sulfate contents implies that these soil factors have an equal contribution to rating of soil corrosivity. A polyethylene wrapping and use of non-conducting materials could be sufficient for the extension of their life up to 50 years or more. Furthermore, a new probabilistic corrosion failure model is proposed for the study of soil corrosivity level more precisely based on sub-corrosive group. The outputs of the present work could be very useful in the formulation and implementation strategies to control or minimize the corrosion effect of buried metallic pipes in Kathmandu Valley. नेपालका शहरी क्षेत्रमा खानेपानी वितरणका लागि प्रयोग गरिँदै आएका फलामबाट बनेका यौगिक धातुबाट पाइपको क्षयिकरण (Corrosion) प्रक्रियाबाट त्यस्ता पाइपको क्षति भई वर्षेनी ठूलो मात्रामा खाने पानीको अभाव तथा आर्थिक क्षति हुँदै आएको कुरालाई मध्यनजर गर्दै उक्त पानी वितरण गर्ने जनिमूनी विछ्याइएका लोहाजन्य पाइपहरुको क्षयिकरण गर्ने प्रमुख कारकका रुपमा रहेका माटोको गुणहरु जस्तै पानीको मात्रा, अम्लियपन, विद्युतीय प्रतिराधोत्मक क्षमता, अक्सिडेसन–रिडक्सन क्षमता, क्लोराईड, सल्फेट जस्ता कणहरुको अन्तर्राष्ट्रिय मापदण्डहरु जस्तै ASTM, NACE र AWWA विधिहरु प्रयोग गरी विश्लेषण गर्दा काठमाडौँ उपत्यकाको माटोको क्षयिकरण तहहरु मुख्यतः निम्न तथा मध्यमस्तर रहेको विद्यावारिधी अनुसन्धानबाट पाइएको छ । यस किसिमका अनुसन्धान परीक्षणबाट यो अनुमान गर्न सकिन्छ कि उक्त निम्न तथा मध्यम स्तरका माटोको क्षयिकरण गुणहरुलाई अझ कम गर्नका लागि सरल र कम खर्चिलो तरिकाले बालुवाजन्य माटोका कणहरु विछ्याइएका पानीका पाइप वरिपरि प्रयोग गर्ने विधि पनि एउटा प्रभावशाली हुनेछ । पानीको मात्रा विद्युतीय प्रतिरोधात्मक क्षमता, क्लोराइड र सल्फेट कणहरु बीचको आपसी सम्बन्ध विश्लेषण गर्दा दुवै घनात्मक र ऋणात्मक गुणक (Positive and negative correlation coefficient) पाइएकोले माटोका यी गुणहरु क्षयिकरण वर्गीकरणका लागि समान योगदान रहेको कुरालाई संकेत गर्छ । माटो क्षयिकरणलाई सशक्त रुपमा वर्गीकरण गर्नका लागि नविनतम सम्भावित माटो क्षयिकरण मोडेल यस अध्ययनमा पेश गरिएको छ । यस अध्ययनको परिणामले माटो क्षयिकरण क्षमतालाई नियन्त्रण गर्न रणनीतिक रुपमा प्रयोग गर्न सकिने विश्वास गरिएको छ ।Item Adsorptive Removal of Fe (II) From Aqueous Solution by Functionalized Sugarcane Bagasse(Department of Chemistry, 2010) Acharya, MahendraIn the present study, adsorption of Fe(II) onto different biosorbents prepared from sugarcane bagasse, i.e, raw sugarcane bagasse, charred sugarcane bagasse and phosphoric acid modified charred sugarcane bagasse has been studied by batch equilibration method under different experimental conditions. Effects of pH, Fe(II) concentration, and contact time on the adsorption of divalent iron ion were investigated. The concentration of Fe(II) ion in the test solution was determined spectrophotometrically. Maximum adsorption was observed at pH 2.5 for all the adsorbents at the optimum contact time of 9 hour, 7 hour, and 4 hour respectively for RSB, CSB and PCSB. Maximum adsorption capacity (qmax) value for the RSB, CSB and PCSB was found to be 50.5, 111.4 and 175 mg/g respectively. Adsorption of the Fe(II) ion on all the adsorbents followed Langmuir isotherm more strictly than Freundlich isotherm. The results shows that studied adsorbents may be attractive low cost alternative for the treatment of wastewater in lower concentration of iron.Item Electrophoretic Deposition of Oxidized Multi-Walled Carbon Nanotubes on Stainless Steel for LPG Sensor(Department of Chemistry, 2023) Chaudhary, RimaThis dissertation research describes the feasibility study and investigation of Electrophoretic Deposition of oxidized MWCNTs on stainless steel for LPG sensor. Gas sensors are attracting tremendous interest because of their wide spread application in industry, environmental monitoring, space exploration, biomedicine and pharmaceuticals. Gas sensors with high sensitivity and selectivity are required for leakage detection of explosive gases such as hydrogen, and for real time detection of toxic and pathogenic gases in industries. There is also a strong demand for the ability to monitor and control our ambient environment, especially with the increasing concern of global warming. MWCNTs are used to obtain thin film by Electrophoretic Deposition. Before deposition MWCNTs were purified and surface functionalized by conc. HNO 3 . The oxidized MWCNTs were characterized by FTIR. FTIR shows the presence of oxygenated functionalized groups as carboxylic acid and hydroxyl group on the surface of MWCNTs. The uniform Electrophoretic deposition of MWCNTs are confirmed by SEM. Raman spectroscopy confirmed the deposited material was MWCNTs. The EPD experiments were carried out by using oxidized MWCNTs on stainless steel plate at 10V at a constant time of 10 min. and fix electrode distance of 1.5 cm. Modification of carbon nanotubes with functional groups will greatly enhance the selectivity of the carbon nanotubes-based gas sensors have proved to work well at room temperature, which reduces power consumption of the device and enables the safer detection of flammable gases. The resistance of Electrophoretic deposited material was measured in closed glass chamber with digital multimeter. Then % sensitivity was calculated. It was observed that the rate of sensitivity increases with time and become constant after certain time.