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Synthesis and Electrochemical Characterization of AgNP Ink Suitable for Inkjet Printing
摘要： To meet the growing demand for inkjet printable nanoparticle-based conductive inks, novel synthetic approaches are needed. In this study, spherical silver nanoparticles (AgNPs) with a mean diameter of approximately 2.5 nm were synthesized by the reduction of silver nitrate using an aqueous hydrazine solution in the presence of poly(acrylic acid) as a capping agent. The main goal of this work was the implementation of cyclic voltammetry as an electrochemical method for studying both the absorption of poly(acrylic acid) on the grain surface and nanoparticle interactions. The same technique was used to determine equimolar additions of hydrazine to obtain a high yield of reduced silver. All solutions used in the experiments were prepared at a high molar concentration. Silver nanoparticle-based ink was prepared by dispersing dried nanoparticles into a mixture of water and ethylene glycol and was stable for over seven months. For a comprehensive study of the prepared nanoink, UV-visible and electronic microscopy measurements were carried out. An inkjet technology was applied to deposit conductive ink to form linear silver tracks on a flexible substrate. These tracks exhibited a resistivity of 8.0×10-8 ?m.
关键词： conductive ink,poly(acrylic acid),cyclic voltammetry,Inkjet printing,silver nanoparticles
更新于2025-09-09 09:28:46
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Optimization, kinetics and thermodynamics of photocatalytic degradation of Acid Red 1 by Sm-doped CdS under visible light
摘要： Sm-doped CdS nanoparticles were synthesized through an ultrasound-assisted co-precipitation method and their photocatalytic efficiency was investigated by applying them to photodegradation of Acid Red 1 (AR1) under visible light. The effect of the operational factors on the photocatalytic process was systematically evaluated using response surface methodology. Under the optimal conditions ([AR1]0= 15 mg L-1, [2% Sm-CdS]0= 1 g L-1, pH= 4 and t= 94 min), more than 83% of the AR1 molecules were degraded. The kinetics of the process was well described by the Langmuir-Hinshelwood’s pseudo-first-order model (kapp= 0.0163 min-1). Furthermore, thermodynamics of the process was demonstrated by the activated complex theory of Eyring, which declared that the photocatalytic process is endothermic and nonspontaneous in the temperature range of 25–45°C. In addition, the main products and intermediates of AR1 degradation were determined by the GC-MS technique.
关键词： Sm-doped CdS,Thermodynamics,Visible light photocatalysis,Kinetics,Acid Red 1,RSM
更新于2025-09-09 09:28:46
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Label-free detection of folic acid using a sensitive fluorescent probe based on ovalbumin stabilized copper nanoclusters
摘要： In this work, ovalbumin (OVA) stabilized copper nanoclusters (OVA-Cu NCs) were prepared through a simple protein-stabilized synthetic method and applied for the sensitive determination of FA. Cu2+ ions were directly reduced to Cu (0) by a mild reducing agent, N2H4·H2O, at room temperature without any other complicated procedure such as adjusting pH and controlling the temperature of the reaction mixture. The as-prepared OVA-Cu NCs showed good chemical stability, wonderful water solubility and excellent biocompatibility. The OVA-Cu NCs were obtained with an average particle size of 2.0 nm and good dispersibility in aqueous solution. They also showed strong red emitting at 625 nm with a quantum yield of 3.95%. The OVA-Cu NCs were then applied for label-free detection of FA based on a static quenching mechanism. The linear calibration curve of detecting FA served from 0.5 μM -200 μM with the detection limit of 0.18 μM. In addition, the developed method was also successfully applied to determine the content of FA in tablet, spinach, orange juice and biological samples with quantitative spike recoveries from 96.9% to 100.9%. For these reasons, the developed OVA-Cu NCs-based fluorescent strategy can thus offer a convenient label-free biosensor platform for the detection of FA in biomedical applications.
关键词： label-free detection,folic acid,red emitting,copper nanoclusters
更新于2025-09-09 09:28:46
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Orientation of Pterin-6-Carboxylic Acid on Gold Capped Silicon Nanopillars Platforms: Surface Enhanced Raman Spectroscopy and Density Functional Theory Studies
摘要： The orientation of pterin-6-carboxylic acid on gold nanopillars was investigated by surface enhanced Raman spectroscopy and density functional theory methods. The experimentally vibrations from pterin-6-COOH free and attached to the Au surface display vibration features indicating chemical interaction of the pterin with the metal surface. The spectral feature evidenced that the pterin would adsorb on gold surface with a “lying down” configuration through the high intensity vibration of NH scissoring and rocking OH modes. The orientation study of pterins on gold nanopillars presented herein is believed to lead to new applications in biosensing field for detecting pterins of physiological importance.
关键词： SERS,gold nanopillar,DFT,pterin-6-carboxylic acid
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Synthesis and characterization of TiO2 co-polymeric hydrogel
摘要： In this study, TiO2 doped acrylic acid-co-vinyl pyrrolidone (AA-co-VP) composite co-polymeric hydrogel was synthesized by free radical polymerization technique. Titanium dioxide (TiO2) were chosen because of its superior properties such as high activity, chemical stability, low cost, non-toxicity, and stability during irradiation. TiO2 doping were carried out by varying mass ratios as 0.05%, 0.5% and 1%. Conversion, cross-linking and swelling values of each hydrogel were calculated. According to swelling behavior, while TiO2 dope ratio increase, swelling value was also increased. Chemical, morphological and thermal properties of hydrogels were specified by using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDX), mapping and thermogravimetric analysis (TGA-DSC) techniques. TiO2 doping provides superior properties to co-polymeric hydrogel. Hydrogels have also characteristic properties of both acrylic acid and vinyl pyrrolidone.
关键词： SEM-EDX,hydrogel,TGA-DSC,free radical polymerization,acrylic acid-co-vinyl pyrrolidone,FTIR,TiO2,swelling behavior
更新于2025-09-09 09:28:46
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Association between seasonal serum folate levels and ultraviolet radiation
摘要： UV radiation has been consistently reported to cause folate photodegradation in vitro and in human skin. Seasonal variations in UV radiation might explain seasonal changes in folate levels in blood. Yet, few studies have addressed this phenomenon. The main objective of this study was to investigate whether a relationship exists between seasonal variations in serum folate levels in a population of Spain (Latitude: 36° 41' 6.88''; Longitude: 4° 30' 0.64'') and the annual variations of solar ultraviolet reached in the localization. From a sample of 118831 serum folate determinations, two studies were performed. The first one, which included all subjects, showed a decreased in mean folate concentrations in all seasons with respect to winter with lower values in summer. The risk of folate deficiency was 1.37 times greater in summer than in winter (95%CI: 1.29-1.46). In the second study, subjects with a first folate determination in winter and a second one in summer were 3.32 more likely to develop folate deficiency than those with a first folate determination in summer and a second one in winter (95%CI: 1.55 to 7.11). Folate levels showed a seasonal variation inversely related to solar total UV radiation reached in our location, with maximum daily doses of 5000 J m-2 reached in June. A gradual increase in percentage of folate deficiency is observed since spring. So, patients with folate levels close to deficiency are at a higher risk of having folate deficiency in summer.
关键词： folic acid,solar ultraviolet radiation,seasonal variation,folate deficiency,folate,photodegradation,population study
更新于2025-09-09 09:28:46
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Lewis-Acid-Catalyzed BODIPY Boron Functionalization Using Trimethylsilyl Nucleophiles
摘要： A novel and straightforward strategy for boron functionalization in boron dipyrromethenes (BODIPYs) is developed. In particular, this synthetic strategy provides new possibilities for the synthesis of sp2 N-substituted (B-NCS and -NCO), benzotriazole- and trifluoroacetamide-substituted BODIPYs that were hitherto unknown. These new BODIPYs display an array of highly desirable photophysical properties (0.04 < Φ f < 0.86), paving the road for further investigations in material applications.
关键词： photophysical properties,boron functionalization,trimethylsilyl nucleophiles,Lewis acid catalysis,BODIPY
更新于2025-09-09 09:28:46
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Effect of Acid and Base of Different Brands of Mefenamic Acid by UV Spectrophotometeric Method
摘要： Mefenamic acid belongs to class of drug NSAIDS (non-steroidal anti-inflammatory drugs). Mefenamic acid inhibits the synthesis and actions of prostaglandins and it also block the COX-1 and COX-2 or COX enzyme. The purpose of this research is to study the effect of acid and base by using UV spectrophotometry, on different brands of mefenamic acid under ICH guideline Q1A (R2). According to USP, mefenamic acid contains not less than 98 % and not more than 102 % of C15H15NO2 calculated on dried basis. The result concludes that when chosen brands of mefenamic acid i.e. dolor (A), postron forte (B), mefnac (C), positron (D), garden forte (E) were subjected to 0.1 N HCl (acidic medium), highly considerable degradation were observed in all the brands i.e. D (23.10 %), A (24.46 %), E (34.95 %), B (43.02 %) and C (66.34 %). Similarly when different brands of mefenamic acid were subjected to 0.1 N NaOH, highly considerable degradation were observed in the brand A, B (187.44 % and 124.38 %), C (51.93 %) and no degradation were observed in brand D and E (88.75 %) and (89.09 %). It is most commonly preferred as compare to other methods because of less time consuming and maintenance cost and can be use in routine quality control laboratories.
关键词： IUPAC formula,Mefenamic acid,NSAIDS,Compounds
更新于2025-09-09 09:28:46
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Clickable PNA Probes for Imaging Human Telomeres and Poly(A) RNAs
摘要： The ability to bind strongly to complementary nucleic acid sequences, invade complex nucleic acid structures, and resist degradation by cellular enzymes has made peptide nucleic acid (PNA) oligomers as very useful hybridization probes in molecular diagnosis. For such applications, the PNA oligomers have to be labeled with appropriate reporters as they lack intrinsic labels that can be used in biophysical assays. Although solid-phase synthesis is commonly used to attach reporters onto PNA, development of milder and modular labeling methods will provide access to PNA oligomers labeled with a wider range of biophysical tags. Here, we describe the establishment of a postsynthetic modification strategy based on bioorthogonal chemical reactions in functionalizing PNA oligomers in solution with a variety of tags. A toolbox composed of alkyne- and azide-modified monomers were site-specifically incorporated into PNA oligomers and postsynthetically click-functionalized with various tags, ranging from sugar, amino acid, biotin, to fluorophores, by using copper(I)-catalyzed azide?alkyne cycloaddition, strain-promoted azide?alkyne cycloaddition, and Staudinger ligation reactions. As a proof of utility of this method, fluorescent PNA hybridization probes were developed and used in imaging human telomeres in chromosomes and poly(A) RNAs in cells. Taken together, this simple approach of generating a wide range of functional PNA oligomers will expand the use of PNA in molecular diagnosis.
关键词： peptide nucleic acid,bioorthogonal chemical reactions,molecular diagnosis,poly(A) RNAs,human telomeres,PNA,click chemistry
更新于2025-09-09 09:28:46
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Criticial Assessment of the Photocatalytic Reduction of Cr(VI) over Au/TiO2
摘要： The puri?cation of drinking water is one of the most urgent challenges in developing countries, for which the ef?cient removal of traces of heavy metals, e.g., Cr(IV), represents a key technology. This can be achieved via photocatalysis. In this study, we compare the performance of Au/TiO2 to bare TiO2 P25 catalysts. Furthermore, the in?uence of the sacri?cial reagent citric acid under UV-Vis and Vis excitation was investigated and a detailed investigation of the catalysts before and after reaction was performed. During the photocatalytic reduction of Cr(IV) under acidic conditions, both leaching of Au, as well as absorption of Cr, occur, resulting in new catalyst systems obtained in situ.
关键词： Au/TiO2,adsorption,photocatalysis,Cr(VI) reduction,citric acid
更新于2025-09-09 09:28:46