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Water electrolyzers powered by renewable energy are emerging as clean and sustainable technology for producing hydrogen without carbon emissions. Specifically, anion exchange membrane (AEM) electrolyzers utilizing non-platinum group metal (non-PGM) catalysts have garnered attention as a cost-effective method for hydrogen production, especially when integrated with solar cells. Nonetheless, the progress of such integrated systems is hindered by inadequate water electrolysis efficiency, primarily caused by poor oxygen evolution reaction (OER) electrodes. To address this issue, a NiFeCoâOOH has developed as an OER electrocatalyst and successfully demonstrated its efficacy in an AEM electrolyzer, which is powered by renewable electricity and integrated with a silicon solar cell.
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Corrosion is considered as one of the main factors in the structural performance deterioration of steel members. In this study, experimental and numerical methods were used to assess the reduction in compressive strength of short tubular steel columns with artificially fabricated local corrosion damage. The corrosion damage was varied with different depths, heights, circumferences, and locations along the column. A parametric numerical study was performed to establish a correlation between the residual compressive strength and the severity of corrosion damage. The results showed that as the corrosion depth, height and circumference increased, the compressive strength decreased linearly. As for the corrosion height, the residual compressive strength became constant after decreasing linearly when the corrosion height was greater than the half-wavelength of buckling of the short columns. An equation is presented to evaluate the residual compressive strength of short columns with local corrosion wherein the volume of the corrosion damage was used as a reduction factor in calculating the compressive strength. The percentage error using the presented equation was found to be within 11.4%.
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In this study, a time-dependent corrosion depth estimation method using atmospheric corrosion monitor (ACM) sensor data to evaluate time-dependent corrosion behaviors is proposed. For the time-dependent corrosion depth estimation of uncoated carbon steel and weathering steel, acceleration corrosion tests were conducted in salt-spray corrosion environments and evaluated with a corrosion damage estimation method using ACM sensing data and corrosion loss data of the tested steel specimens. To estimate the time-dependent corrosion depth using corrosion current by an ACM sensor, the relationship between the mean corrosion depth calculated from the weight loss method and the corrosion current was evaluated. The mean corrosion depth was estimated by calculating the corrosion current and evaluating the relationship between the mean corrosion depth and corrosion current during the expected period. From the test and estimation results, the corrosion current demonstrated a good linear correlation with the mean corrosion depth of carbon steel and weathering. The calculated mean corrosion depth is nearly the same as that of the tested specimen, which can be well used to estimate corrosion rate for the uncoated carbon steel and weathering steel.
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PURPOSE: To investigate the clinical manifestations and properties of remnant particles in the subconjunctival space after high-frequency radio-wave electrosurgery for conjunctivochalasis. METHODS: We performed a retrospective, observational case series with in vitro experimental imaging in nine eyes from eight patients who presented with small dark-gray lesions during follow-up after high-frequency radio-wave electrosurgery for conjunctivochalasis. General examination including slit-lamp examination and visual acuity testing was performed preoperatively and postoperatively. During follow-up, we evaluated remnant particles and any other complications including granuloma or conjunctival injection with slit-lamp photography and anterior optical coherence tomography. Coagulation tips were investigated with scanning electron microscope and energy dispersive X-ray spectroscopy to analyze the insulating electrode and assess changes to tips after repeated use. RESULTS: None of the patients included in this study experienced any change in visual acuity or major complications postoperatively. Small dark-gray lesions (0.3 to 0.5 mm in size) were observed in the inferior bulbar sub-conjunctival space in the location where high-frequency radio-wave electrosurgery had been performed. Cirrus high-definition optical coherence tomography images revealed focal hyper-reflection with a posterior shadow, suggesting foreign particles. Scanning electron microscopy and energy dispersive X-ray spectroscopy imaging analysis revealed peaks of carbon and fluorine complexes, consistent with the polytetrafluoroethylene coating on the electrode. CONCLUSIONS: There were no instances of inflammatory reaction, particle migration, or major complications due to particles. Physicians should be aware of the possibility of remnant polytetrafluoroethylene particles in subconjunctival tissue when using insulated coagulation tips subjected to repeat sterilization.
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Conjuntiva/ultraestructura , Enfermedades de la Conjuntiva/cirugía , Electrocirugia/métodos , Terapia por Radiofrecuencia , Anciano , Conjuntiva/cirugía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Estudios Retrospectivos , Microscopía con Lámpara de Hendidura , Tomografía de Coherencia Óptica , Resultado del TratamientoRESUMEN
PURPOSE: The purpose of this study was to investigate the association between factors associated with parturition and open-angle glaucoma (OAG) in Korean females. METHODS: A population-based, cross-sectional survey was performed from the Korean National Health and Nutrition Examination Survey from 2010 to 2011 and enrolled postmenopausal female participants (n=1798). We obtained information on demographics, comorbidities, and health-related behaviors and performed comprehensive ophthalmic examinations. Multivariate regression analysis was used to assess the correlation between pregnancy and delivery and the prevalence of OAG in all enrolled subjects. RESULTS: The prevalence of OAG among study participants was 6.42%. There was a significant difference in the number of deliveries and age at first delivery between the OAG group and the nonglaucoma group. In multiple linear regression models adjusted for age, hypertension, and intraocular pressure only pregnancy 1 was associated with higher risk of OAG compared with pregnancy 2 (P=0.023). Subjects who had 3 or 4 deliveries were at higher risk of OAG compared with subjects with 2 deliveries (P=0.027). An age at first delivery of 16 to 20 years or 21 to 23 years was associated with increased OAG risk compared with the reference group (P<0.05). CONCLUSIONS: A history of three or more deliveries and an age at first delivery younger than 23 years were associated with increased risk of OAG. These results suggest that changes or events during the period from pregnancy to delivery affect the development of glaucoma.
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Glaucoma de Ángulo Abierto/epidemiología , Parto/fisiología , Embarazo/fisiología , Adulto , Anciano , Estudios Transversales , Femenino , Glaucoma de Ángulo Abierto/fisiopatología , Humanos , Presión Intraocular/fisiología , Modelos Lineales , Edad Materna , Persona de Mediana Edad , Encuestas Nutricionales/estadística & datos numéricos , Paridad/fisiología , Prevalencia , República de Corea/epidemiología , Tonometría Ocular , Adulto JovenRESUMEN
An irreversible thermochromic material based on manganese violet (MnNH4P2O7) is synthesized. The crystal phase, chemical composition, and morphology of the synthesized material are analyzed using X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, and Fourier-transform infrared spectroscopy. The absorption spectra of the synthesized material are obtained using a UV-Vis spectrometer, and the thermochromism exhibited by the powdered samples at high temperatures is also investigated. The as-synthesized manganese violet pigment consists of pure α-MnNH4P2O7 phase. In addition, the synthesized pigment largely consists of hexagonal crystals with a diameter of hundreds of nanometers. On heating, the pigment simultaneously loses H2O and NH3 in two successive steps at approximately 330â»434.4 °C and 434.4â»527 °C, which correspond to the formation of an intermediate phase and of Mn2P4O12, respectively. An overall mass loss of 14.22% is observed, which is consistent with the expected 13.79%. An irreversible color change from violet to white is observed after exposure of the synthesized manganese violet pigment at 400 °C for 30 min. This is attributed to the oxidation of ammonia to hydroxylamine, which then decomposes to nitrogen and water, or alternatively to the direct oxidation of ammonia to nitrogen. Furthermore, we demonstrate the potential application of synthesized manganese violet in the production of irreversible thermochromic paint by mixing with potassium silicate solution as a binder and deionized water as a solvent at a specific ratio. The thermochromic paint is then applied in fabrication of irreversible thermochromic sensors by coating it onto a steel plate surface. Finally, we show that manganese violet-based irreversible thermochromic sensors are able to detect temperatures around 400 °C by changing color from violet to white/milky.
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An inorganic thermochromic material based on Cr-doped Al2O3 is synthesized using a solid-state method. The crystal structure, chemical composition, and morphology of the synthesized material are analyzed using X-ray diffraction, scanning electron microscopy coupled with an energy-dispersive X-ray spectrometer, and Fourier transform infrared (FT-IR) spectroscopy. The color performances of the synthesized material are analyzed using a UV-VIS spectrometer. Finally, the thermochromism exhibited by the powdered samples at high temperatures is investigated. The material exhibits exceptional thermochromic property, transitioning from pink to gray or green in a temperature range of 25-600 °C. The change in color is reversible and is dependent on the surrounding temperature and chromium concentration; however, it is independent of the exposure time. This novel property of Cr-doped Al2O3 can be potentially employed in reversible thermochromic sensors that could be used not only for warning users of damage due to overheating when the environmental temperature exceeds certain limits, but also for detecting and monitoring the temperature of various devices, such as aeronautical engine components, hotplates, and furnaces.
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AIMS: To investigate the association between plasma homocysteine levels and glaucomatous retinal nerve fiber layer (RNFL) defect in South Korean population. MATERIALS AND METHODS: This retrospective cross-sectional study included subjects who underwent screening at Kangbuk Samsung Hospital Health Screening Center between August 2012 and July 2013. Subjects underwent physical examination and provided samples for laboratory analysis of homocysteine. Subjects were divided equally into four quartiles (Qs) based on plasma homocysteine level. Digital fundus photographs of both eyes were obtained. Determination of glaucomatous disc appearance was based on criteria set forth by the International Society of Geographical and Epidemiological Ophthalmology and based on the appearance of the RNFL and optic disc. Multivariate logistic regression models were used to define elevated glaucoma risk with P < 0.2 on univariate analysis. RESULTS: A total of 78,049 subjects were included; 76,093 subjects were male, and 1956 subjects were female. When analyzed by gender, the mean homocysteine level in the male group with glaucomatous RNFL defects (11.05 ± 3.80 µmol/L) was higher than those without RNFL defects (10.81 ± 4.12 µmol/L (P = 0.000, χ2 test). Upon multifactorial logistic regression analysis adjusted for age, gender, creatinine, diabetes mellitus, hypertension, and hyperlipidemia, glaucomatous RNFL defects had a significant correlation with plasma homocysteine level. Based on the Q2 level, the odds ratio (OR) of Q3 was 1.267, while the OR of Q4 was 1.285 (95% CI = 1.067-1.505, 1.081-1.529, respectively, P for trend = 0.001). CONCLUSION: Our results suggest that homocysteine level is associated with the presence of glaucomatous RNFL defects.
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Glaucoma/sangre , Homocisteína/sangre , Presión Intraocular/fisiología , Fibras Nerviosas/patología , Células Ganglionares de la Retina/patología , Tomografía de Coherencia Óptica/métodos , Adulto , Biomarcadores/sangre , Estudios Transversales , Femenino , Estudios de Seguimiento , Glaucoma/diagnóstico , Glaucoma/fisiopatología , Humanos , Masculino , Estudios RetrospectivosRESUMEN
In this study, the seroprevalences of measles, mumps, and rubella antibodies in infants were determined to assess the immunization strategy and control measures for these infectious diseases. Serum samples from infants < 1 year of age and their mothers were collected to measure the concentrations of specific IgG antibodies to measles, mumps, and rubella by enzyme-linked immunosorbent assay. For selected infant serum samples, measles-specific neutralizing antibody levels were determined by using the plaque reduction neutralization test. The sera from 295 of infants and 80 of their mothers were analyzed. No infants had past measles, mumps, or rubella infections. Almost all infants < 2 months of age were positive for measles and rubella IgG antibodies. However, seroprevalence of measles and rubella antibodies decreased with age, and measles IgG and rubella IgG were barely detectable after 4 months of age. The seroprevalence of mumps antibodies was lower than that of measles and rubella antibodies in infants ≤ 4 months old, and mumps IgG was barely detectable after 2 months of age. The seropositivity of measles-specific neutralizing antibody was 63.6% in infants aged 2 months and undetectable in infants ≥ 6 months old. Because the seropositivity rates of measles, mumps, and rubella antibodies were low after the first few months of age in Korean infants, active immunization with vaccines is strongly recommended for infants aged 6-11 months when measles is epidemic. Timely administration of the first dose of measles-mumps-rubella vaccine at 12 months of age should be encouraged in non-epidemic situations.
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Anticuerpos Antivirales/sangre , Inmunoglobulina G/sangre , Adulto , Anticuerpos Neutralizantes/sangre , Pueblo Asiatico , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Lactante , Masculino , Sarampión/prevención & control , Vacuna contra el Sarampión-Parotiditis-Rubéola/inmunología , Morbillivirus/inmunología , Paperas/prevención & control , Virus de la Parotiditis/inmunología , República de Corea , Rubéola (Sarampión Alemán)/prevención & control , Estudios SeroepidemiológicosRESUMEN
Although the overall incidence of hepatitis A in Korea has been decreasing, adolescents remain highly vulnerable to its outbreaks. This study was conducted to compare the immunogenicity and safety of three hepatitis A vaccines in Korean adolescents. Healthy anti-hepatitis A virus seronegative subjects aged 13 to 19 yr were randomized in three equal groups to receive two doses of Avaxim™, Epaxal®, or Havrix®, 6 to 12 months apart. Seroconversion rates one month after the first dose were 98%, 95%, and 93% for Avaxim™, Epaxal®, and Havrix®, respectively. Seroconversion rates reached 100% for all vaccine groups one month after the second dose. Anti-HAV geometric mean concentrations (GMCs) were 7,207.7 mIU/mL (95% CI, 6023.1-8684.7), 1,750.5 mIU/mL (95% CI, 1362.9-2248.3), and 1,953.5 mIU/mL (95% CI, 1459.4-2614.7) after two doses of Avaxim™, Epaxal®, and Havrix® respectively. Avaxim™ was significantly more immunogenic than Epaxal® and Havrix®, whereas there were no significant differences in antibody responses between Epaxal® and Havrix®. Local and systemic solicited adverse events (AEs) were mostly of mild-to-moderate intensity and resolved within 5 days. No serious AEs were reported. In conclusion, all three vaccines are highly immunogenic and well-tolerated in Korean adolescents. (Clinical Trial Registry NCT00483470).
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Vacunas contra la Hepatitis A/inmunología , Hepatitis A/prevención & control , Adolescente , Formación de Anticuerpos , Femenino , Hepatitis A/inmunología , Anticuerpos de Hepatitis A/sangre , Vacunas contra la Hepatitis A/efectos adversos , Humanos , Masculino , República de Corea , Vacunas de Productos Inactivados/efectos adversos , Vacunas de Productos Inactivados/inmunología , Adulto JovenRESUMEN
Chemical force microscopy analyzes the interactions between various chemical/biochemical moieties in situ. In this work we examined force-distance curves and lateral force to measure the interaction between modified AFM tips and differently functionalized molecular monolayers. Especially for the measurements in gas phase, we investigated the effect of humidity on the analysis of force-distance curves and the images in lateral force mode. Flat chemical patterns composed of different functional groups were made through micro-contact printing and lateral force mode provided more resolved analysis of the chemical patterns. From the images of 1-octadecanethiol/11-mercapto-1-undecanoic acid patterns, the amine group functionalized tip brought out higher contrast of the patterns than an intact silicon nitride tip owing to the additional chemical interaction between carboxyl and amine groups. For more complex chemical interactions, relative chemical affinities toward specific peptides were assessed on the pattern of 1-octadecanethiol/phenyl-terminated alkanethiol. The lateral image of chemical force microscopy reflected specific preference of a peptide to phenyl group as well as the hydrophobic interaction.
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Gases/química , Microscopía de Fuerza Atómica/métodos , Benceno/química , Ácidos Grasos/química , Péptidos/química , Compuestos de Sulfhidrilo/químicaRESUMEN
OBJECTIVES: To evaluate the association between catecholamine levels and skin prick test results among children. METHODS: Two hundred eight first grade children from one elementary school were invited to participate in this study. Skin prick test (SPT) for six allergens (2 house dust mites, cat, dog, mugwort, and pollen mixture) was performed, and patient demographic information was recorded. The parents were surveyed using questionnaires about rhinitis-related symptoms. Finally, venous blood sampling was done to measure catecholamine levels (epinephrine, norepinephrine, and dopamine) by high-performance liquid chromatography. RESULTS: Out of 208 children, 174 (106 boys and 68 girls) enrolled in this study. Ninety-six of the children (55%) had negative SPT (nonsensitization group), while 78 (45%) had a positive SPT to at least one of six allergens (sensitization group). The diagnosis of chronic rhinitis was more prevalent in the sensitization group (35.9%) than nonsensitization group (26.0%), however the finding was not significant (P=0.186). Epinephrine levels were decreased between the sensitization group compared to the nonsensitization group (P=0.004). There was no difference in norepinephrine and dopamine levels (P>0.05). CONCLUSION: Epinephrine levels are lower in children with positive SPT compared to controls, however, the level of the catecholamine was not associated with the presence or absence of rhinitis symptoms.
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OBJECTIVES: A number of otolaryngic conditions such as chronic tonsillitis, adenoid hypertrophy, and obstructive sleep apnea are associated with oxidative stress and elevated levels of serum oxidants. The objective of this study is to measure changes in urine biomarkers of oxidative stress in children after adenotonsillectomy. METHODS: Twenty-two children with sleep disordered breathing (SDB) with tonsil and adenoid hypertrophy were enrolled prior to adenotonsillectomy. Controls consisted of 20 healthy children. Urine samples were collected from all patients. Levels of three urinary biomarkers for oxidative status, 8-hydroxy-2-deoxyguanosine (8-OxodG), F(2)-isoprostane, and malondialdehyde (MDA) were measured using high performance liquid chromatography. For the study group, urine samples were repeated 3 weeks after surgery. RESULTS: In the study group, preoperative urinary levels of 8-OxodG were higher than in controls (p=0.015). Levels decreased after surgery compared to preoperative levels (p=0.002), and reached control levels (p=0.167) at 3 weeks. Levels of urinary F(2)-isoprostane were similar in both groups (p=0.252), but decreased significantly after surgery (p=0.020). CONCLUSIONS: Children with SDB have elevated levels of urinary 8-OxodG, a marker of oxidative stress. Adenotonsillectomy results in decreased 8-OxodG and F(2)-isoprostane. These findings suggest that urine analysis may represent a valuable tool for the measurement of oxidative stress.
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Biomarcadores/orina , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/orina , Síndromes de la Apnea del Sueño/cirugía , Tonsilitis/cirugía , Adenoidectomía , Niño , Preescolar , Cromatografía Líquida de Alta Presión , Femenino , Humanos , Hipertrofia/cirugía , Masculino , Síndromes de la Apnea del Sueño/metabolismo , Tonsilectomía , Tonsilitis/metabolismoRESUMEN
Plasma medicine is an upcoming research area that has attracted the scientists to explore more deeply the utility of plasma. So, apart from the treating biomaterials and tissues with plasma, we have studied the effect of soft plasma with different feeding gases such as Air, N2 and Ar on modification of biomolecules. Hence, in this work we have used the soft plasma on biomolecules such as proteins ((Hemoglobin (Hb) and Myoglobin (Mb)), calf thymus DNA and amino acids. The structural changes or structural modification of proteins and DNA have been studied using circular dichroism (CD), fluorescence spectroscopy, protein oxidation test, gel electrophoresis, UV-vis spectroscopy, dynamic light scattering (DLS) and 1D NMR, while Liquid Chromatograph/Capillary Electrophoresis-Mass Spectrometer (LC/CE-MS) based on qualitative and quantitative bio-analysis have been used to study the modification of amino acids. Further, the thermal analysis of the protein has been studied with differential scanning calorimetry (DSC) and CD. Additionally, we have performed docking studies of H2O2 with Hb and Mb, which reveals that H2O2 molecules preferably attack the amino acids near heme group. We have also shown that N2 gas plasma has strong deformation action on biomolecules and compared to other gases plasma.
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Oxidación-Reducción , Aminoácidos/química , Animales , Sitios de Unión , Rastreo Diferencial de Calorimetría , Bovinos , Dicroismo Circular , ADN/química , Hemoglobinas/química , Espectrometría de Masas , Modelos Moleculares , Mioglobina/química , Resonancia Magnética Nuclear Biomolecular , Unión Proteica , Estructura Secundaria de Proteína , Especies de Nitrógeno Reactivo , Especies Reactivas de OxígenoRESUMEN
A series of phenylbipyridinylpyrazoles was synthesized through the reaction of 2-(4-(2-chloropyridin-4-yl)-3-(3-methoxy-5-methylphenyl)-1H-pyrazol-1-yl)acetonitrile (4) with different 6-substituted pyridine-3-ylboronic acids. The final compounds 5a-j were screened at 10 µM against over 60 tumor cell lines at the U.S. National Cancer Institute (NCI). In light of the NCI results, compounds 5c and 5h showed a broad spectrum of activity against NCI cell lines with mean growth of 53% and 58%, respectively. Compound 5e behaved differently as it showed high degree of selectivity and potency by inhibiting 96% of growth of leukemia SR cell line at 10 µM. Standard COMPARE analyses were performed at the GI50 level and the results exhibit high correlation in the form of pairwise correlation coefficient (PCC) of more than 0.6 between three of the current compounds and three standard known anticancer agents. Compound 5e demonstrated high correlation levels with merbarone (NSC S336628) with a PCC value of 0.631. Compound 5h showed a considerably high PCC value of 0.626 with dichloroallyl lawsone, while compound 5i, showed PCC values of 0.601 and 0.604 with both dichloroallyl lawsone and N,N-dibenzyldaunomycin (NSC S268242), respectively. These three standard agents have anticancer activity via two major mechanism of actions, inhibition of topoisomerase II and inhibition of biosynthesis of pyrimidine nucleotides, therefore, compounds 5a-j are promising therapeutic agents for targeting different human malignancies. Prediction of drug-likeness and toxicity of these newly synthesized derivatives were also considered.
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Antineoplásicos/farmacología , Pirazoles/farmacología , Piridinas/síntesis química , Piridinas/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Antineoplásicos/toxicidad , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , ADN-Topoisomerasas de Tipo II/metabolismo , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Pirazoles/síntesis química , Pirazoles/química , Pirazoles/toxicidad , Piridinas/toxicidad , Inhibidores de Topoisomerasa II/farmacologíaRESUMEN
For the first time, we here propose a green methodology to modify a low bandgap polymer for highly efficient solar cells using atmospheric pressure plasma jet or soft plasma operating on different feeding gases (air, Ar and N2). The physical properties of the modified polymer were investigated using conductivity measurements, UV-visible spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammograms, atomic force microscopy, cathodoluminescence and confocal Raman spectroscopy. Further, we examined the variation of the work function of the polymer before and after plasma treatment using a γ-focused ion beam. Additionally, photovoltaic cells based on the plasma-modified polymer having ITO/PEDOT:PSS/PHVTT (with or without plasma modification):PC71BM/LiF/Al configuration were fabricated and then characterized. We found that the power conversion efficiency (PCE) of the plasma-modified polymer increased dramatically as compared to the control polymer (without plasma treatment). PCE of the control polymer was found to be 4.11%, while after air, Ar and N2 gas plasma treatment the polymer showed PCEs of 4.85%, 4.87% and 5.14% respectively. Thus, plasma treatment not only alters the surface properties, but also modifies the bulk properties (changes in HOMO and LUMO bandgap level). Hence, this work provides new dimensions to explore more about plasma and polymer chemistry.
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Suministros de Energía Eléctrica , Gases em Plasma/química , Polímeros/química , Energía Solar , Tiazoles/química , Diseño de Equipo , Tecnología Química VerdeRESUMEN
We synthesized Pt and PtRu catalysts supported on Nb-doped SnO(2-δ) (Pt/Sn0.99Nb0.01O(2-δ), PtRu/Sn0.99Nb0.01O(2-δ)) for direct oxidation fuel cells (DOFCs) using poly oxymethylene-dimethyl ether (POMMn, n = 2, 3) as a fuel. The onset potential for the oxidation of simulated fuels of POMMn (methanol-formaldehyde mixtures; n = 2, 3) for Pt/Sn0.99Nb0.01O(2-δ) and PtRu/Sn0.99Nb0.01O(2-δ) was less than 0.3 V vs RHE, which was much lower than those of two commercial catalysts (PtRu black and Pt2Ru3/carbon black). In particular, the onset potential of the oxidation reaction of simulated fuels of POMMn (n = 2, 3) for PtRu/Sn0.99Nb0.01O(2-δ) sintered at 800 °C in nitrogen atmosphere was less than 0.1 V vs RHE and is thus considered to be a promising anode catalyst for DOFCs. The mass activity (MA) of PtRu/Sn0.99Nb0.01O(2-δ) sintered at 800 °C was more than five times larger than those of the commercial catalysts in the measurement temperature range from 25 to 80 °C. Even though the MA for the methanol oxidation reaction was of the same order as those of the commercial catalysts, the MA for the formaldehyde oxidation reaction was more than five times larger than those of the commercial catalysts. Sn from the Sn0.99Nb0.01O(2-δ) support was found to have diffused into the Pt catalyst during the sintering process. The Sn on the top surface of the Pt catalyst accelerated the oxidation of carbon monoxide by a bifunctional mechanism, similar to that for Pt-Ru catalysts.
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In this work, we have explored the thermophysical properties of tetraalkylammonium hydroxide ionic liquids (ILs) such as tetrapropylammonium hydroxide (TPAH) and tetrabutylammonium hydroxide (TBAH) with isomers of butanol (1-butanol, 2-butanol and 2-methyl-2-propanol) within the temperature range 293.15-313.15 K, with interval of 5 K and over the varied concentration range of ILs. The molecular interactions between ILs and butanol isomers are essential for understanding the function of ILs in related measures and excess functions are sensitive probe for the molecular interactions. Therefore, we calculated the excess molar volume (V(E) ) and the deviation in isentropic compressibility (Δκs ) using the experimental values such as densities (ρ) and ultrasonic sound velocities (u) that are measured over the whole compositions range at five different temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K) and atmospheric pressure. These excess functions were adequately correlated by using the Redlich-Kister polynomial equation. It was observed that for all studied systems, the V(E) and Δκs values are negative for the whole composition range at 293.15 K. And, the excess function follows the sequence: 2-butanol>1-butanol>2-methyl-2-propanol, which reveals that (primary or secondary or tertiary) position of hydroxyl group influence the magnitude of interactions with ILs. The negative values of excess functions are contributions from the ion-dipole interaction, hydrogen bonding and packing efficiency between the ILs and butanol isomers. Hence, the position of hydroxyl group plays an important role in the interactions with ILs. The hydrogen bonding features between ILs and alcohols were analysed using molecular modelling program by using HyperChem 7.
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Butanoles/química , Líquidos Iónicos/química , Compuestos de Amonio Cuaternario/química , Enlace de Hidrógeno , Electricidad Estática , TemperaturaRESUMEN
In this paper, we have examined the conductivity and interaction studies of ammonium and imidazolium based ionic liquids (ILs) with the newly synthesised low bandgap polymer (Poly(2-heptadecyl-4-vinylthieno[3,4-d]thiazole) (PHVTT)). Use of low bandgap polymers is the most suitable way to harvest a broader spectrum of solar radiations for solar cells. But, still there is lack of most efficient low bandgap polymer. In order to solve this problem, we have synthesised a new low bandgap polymer and investigated its interaction with the ILs to enhance its conductivity. ILs may undergo almost unlimited structural variations; these structural variations have attracted extensive attention in polymer studies. The aim of present work is to illustrate the state of art progress of implementing the interaction of ILs (protic and aprotic ILs) with newly synthesised low bandgap polymer. In addition to this, our UV-Vis spectroscopy, confocal Raman spectroscopy and FT-IR spectroscopy results have revealed that all studied ILs (tributylmethylammonium methyl sulfate ([N1444][MeSO4] from ammonium family) and 1-methylimidazolium chloride ([Mim]Cl, and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl from imidazolium family) have potential to interact with polymer. Our semi empirical calculation with help of Hyperchem 7 shows that protic IL ([Mim]Cl) interacts strongly with the low bandgap polymer through the H-bonding. Further, protic ILs shows enhanced conductivity than aprotic ILs in association with low bandgap polymer. This study provides the combined effect of low bandgap polymer and ILs that may generate many theoretical and experimental opportunities.
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Conductividad Eléctrica , Líquidos Iónicos/química , Polímeros/química , Compuestos de Amonio/química , Enlace de Hidrógeno , Imidazoles/química , Estructura Molecular , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría RamanRESUMEN
Di(3-thienyl)methanol (2) and di(3-thienyl)methane (3) have been synthesized and screened against the T98G (brain cancer) cell line. Treatment induced cell death (MTT and macro-colony assay), growth inhibition, cytogenetic damage (micronuclei formation), were studied as cellular response parameters. Treatment with the compounds enhanced growth inhibition and cell death in a concentration dependent manner in both T98G and HEK (normal) cell lines. At higher concentrations (>20 µg/mL) the cytotoxic effects of the compounds were highly significant. The effect on clonogenic capacity and micronuclei formation observed after treatment of cells. Amongst the compounds, compound 2 exhibited potent activity against T98G brain cancer cells. Despite potent in vitro activity, both compounds exhibited less cytotoxicity against normal human HEK cells at all effective concentrations.