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991.
M.A. Hasnat M.A. Rashed M. Saiful Alam M. Maria Rahman M. Amirul Islam S. Hossain N. Ahmed 《Catalysis communications》2010,11(13):1085-1089
Platinum particles were electrochemically deposited over glassy carbon (GC) to prepare GC-Pt electrodes. The electrocatalytic behaviors of this electrode have been compared with that of an ordinary polycrystalline(OPC) Pt and GC electrode in reducing NO2− at neutral medium. The as prepared GC-Pt electrode reduced NO2−, exhibiting double-peak reduction waves. The reduction performance of this electrode was noticed at least 7.8 times higher than that of an OPC Pt electrode. The sensitivity of the GC-Pt electrode was found to be enhanced by the temperature rise. A consecutive mechanism, NO2− → NO → NH4+, over the as prepared GC-Pt electrode has been investigated. 相似文献
992.
Ihsan Ali M.U. Islam M.S. Awan Mukhtar Ahmad 《Journal of Materials Engineering and Performance》2013,22(7):2104-2114
M-type hexaferrite (BaFe12O19) powders have been synthesized by means of the sol-gel autocombustion technique and is heat treated at 1000 °C for different times (t = 1, 2, 3, and 4 h). Differential scanning calorimetry and thermogravimetric analyses are carried out to observe the weight loss and transformation of different phases during heat treatment. X-Ray diffraction patterns of the sample heat treated for 4 h confirms the formation of single phase M-type hexaferrite. The dielectric parameters and ac conductivity (σac) are measured in the high frequency range 1 MHz-3 GHz. The dielectric properties and ac conductivity are based on the space charge polarization according to the Maxwell-Wagner two-layer model and the Koop’s phenomenological theory. The dielectric constant (ε′) and dielectric loss (tan δ) decrease, while ac conductivity enhances with the increase of frequency. The room temperature DC electrical resistivity of the sample heat treated for 2 h enhances up to 2.93 × 109 (Ω-cm) and attributed to the migration of Fe2+ ions to the neighboring tetrahedral sites and lowering the Fe3+ contents on the octahedral sites. The temperature-dependent DC resistivity of samples shows a normal semiconducting behavior. The saturation magnetization, magnetic moment, and coercivity of the samples are observed to enhance with the increase of heat-treatment time. Owing to these qualities, the synthesized materials may be considered useful for high frequency applications, recording media, and permanent magnets. 相似文献
993.
T. V. Kozlova S. M. Lipkin T. V. Lipkina M. S. Lipkin V. P. Breslavets N. V. Shishka A. V. Ul’yanov 《Protection of Metals and Physical Chemistry of Surfaces》2017,53(7):1304-1310
The aim of this work is to investigate the possibility of the application of the procedure for the prediction of the rate of corrosion for internal surfaces of the pipes of heat-supply systems. As a basis of the system for the evaluation of protective properties of oxide films, gravimetric studies and evaluation of the phase composition of films and their permittivity are chosen. The results of investigations of films show that it is possible to predict the rate of corrosion using not only gravimetric studies, but also the determination of the fraction of free surface and identification of the type and number of phases of the film. These procedures, being involved in the general system, make it possible not only to predict the corrosion process, but also to analyze reasons for its further development. 相似文献
994.
Syful Islam Md Badrul Alam Hyeon-Jin Ann Ji-Hyun Park Sang-Han Lee Sunghwan Kim 《International journal of molecular sciences》2021,22(1)
High-resolution mass spectrometry equipped with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) sources was used to enhance the characterization of phytochemicals of ethanol extracts of Manilkara zapota L. leaves (ZLE). Sugar compounds, dicarboxylic acids, compounds of phenolic acids and flavonoids groups, and other phytochemicals were detected from the leaves. Antioxidant activity and inhibition potentiality of ZLE against α-glucosidase enzyme, and elastase enzyme activities were evaluated in in vitro analysis. ZLE significantly inhibited activities of α-glucosidase enzyme at a lower concentration (IC50 2.51 ± 0.15 µg/mL). Glucose uptake in C2C12 cells was significantly enhanced by 42.13 ± 0.15% following the treatment with ZLE at 30 µg/mL. It also exhibited potential antioxidant activities and elastase enzyme inhibition activity (IC50 27.51 ± 1.70 µg/mL). Atmospheric pressure chemical ionization mass spectrometry (APCI–MS) detected more m/z peaks than electrospray ionization mass spectrometry (ESI–MS), and both ionization techniques illustrated the biological activities of the detected compounds more thoroughly compared to single-mode analysis. Our findings suggest that APCI along with ESI is a potential ionization technique for metabolite profiling, and ZLE has the potential in managing diabetes by inhibiting α-glucosidase activity and enhancing glucose uptake. 相似文献
995.
Imalka H. A. M. Arachchilage Joseph Basi Shahedul Islam Julie P. Harmon 《Polymer Engineering and Science》2021,61(3):680-692
Development of polyurethanes (PU) has come a long way from their origin in 1937 and has unique applications in a diverse set of fields. Recent PU developments are focusing more on the naturally-derived diols in the synthesis process in an effort to make them more environmentally friendly. In this study, three different diisocyanates (aliphatic, cycloaliphatic, and aromatic diisocyanates) were combined with laccol, which extracted from Vietnamese lacquer sap (Toxicodendron succedanea) to synthesize novel PUs. Influence of the different diisocyanates in novel PUs, hydrogen bonding capability, and crosslinking ability were investigated to provide a broader characteristic scope for future developments. Resulting materials illustrated good thermal stability after exposed to higher temperatures and the hydrogen bonding regions corresponding to N H (3326 cm−1) and CO (1652 cm−1) groups were shifted to higher wavenumber according to Fourier transform infra-red spectroscopy analysis. Further curing occurred with temperature treatment and improved the overall quality of novel PUs. Powder X-ray analysis, micro hardness, and swelling analysis were utilized to identify molecular packing and crosslinking effects. Higher crosslink density observed for cycloaliphatic and aromatic diisocyanate incorporated novel polyurethanes compared to aliphatic diisocyanate incorporated polyurethane. 相似文献
996.
Suran Nethisinghe Maheswaran Kesavan Heather Ging Robyn Labrum James M. Polke Saiful Islam Hector Garcia-Moreno Martina F. Callaghan Francesca Cavalcanti Mark A. Pook Paola Giunti 《International journal of molecular sciences》2021,22(14)
Friedreich’s ataxia (FRDA) is a comparatively rare autosomal recessive neurological disorder primarily caused by the homozygous expansion of a GAA trinucleotide repeat in intron 1 of the FXN gene. The repeat expansion causes gene silencing that results in deficiency of the frataxin protein leading to mitochondrial dysfunction, oxidative stress and cell death. The GAA repeat tract in some cases may be impure with sequence variations called interruptions. It has previously been observed that large interruptions of the GAA repeat tract, determined by abnormal MboII digestion, are very rare. Here we have used triplet repeat primed PCR (TP PCR) assays to identify small interruptions at the 5′ and 3′ ends of the GAA repeat tract through alterations in the electropherogram trace signal. We found that contrary to large interruptions, small interruptions are more common, with 3′ interruptions being most frequent. Based on detection of interruptions by TP PCR assay, the patient cohort (n = 101) was stratified into four groups: 5′ interruption, 3′ interruption, both 5′ and 3′ interruptions or lacking interruption. Those patients with 3′ interruptions were associated with shorter GAA1 repeat tracts and later ages at disease onset. The age at disease onset was modelled by a group-specific exponential decay model. Based on this modelling, a 3′ interruption is predicted to delay disease onset by approximately 9 years relative to those lacking 5′ and 3′ interruptions. This highlights the key role of interruptions at the 3′ end of the GAA repeat tract in modulating the disease phenotype and its impact on prognosis for the patient. 相似文献
997.
Jaisan Islam Elina KC Soochong Kim Hyong Kyu Kim Young Seok Park 《International journal of molecular sciences》2021,22(16)
The nucleus accumbens core (NAcc) is an important component of brain reward circuitry, but studies have revealed its involvement in pain circuitry also. However, its effect on trigeminal neuralgia (TN) and the mechanism underlying it are yet to be fully understood. Therefore, this study aimed to examine the outcomes of optogenetic stimulation of NAcc GABAergic neurons in an animal model of TN. Animals were allocated into TN, sham, and control groups. TN was generated by infraorbital nerve constriction and the optogenetic virus was injected into the NAcc. In vivo extracellular recordings were acquired from the ventral posteromedial nucleus of the thalamus. Alterations of behavioral responses during stimulation “ON” and “OFF” conditions were evaluated. In vivo microdialysis was performed in the NAcc of TN and sham animals. During optogenetic stimulation, electrophysiological recordings revealed a reduction of both tonic and burst firing activity in TN animals, and significantly improved behavioral responses were observed as well. Microdialysis coupled with liquid chromatography/tandem mass spectrometry analysis revealed significant alterations in extracellular concentration levels of GABA, glutamate, acetylcholine, dopamine, and citrulline in NAcc upon optic stimulation. In fine, our results suggested that NAcc stimulation could modulate the transmission of trigeminal pain signals in the TN animal model. 相似文献
998.
Minkyu Park Ali Sarkhosh Violeta Tsolova Islam El-Sharkawy 《International journal of molecular sciences》2021,22(19)
While horizontally transferred transposable elements (TEs) have been reported in several groups of plants, their importance for genome evolution remains poorly understood. To understand how horizontally transferred TEs contribute to plant genome evolution, we investigated the composition and activity of horizontally transferred TEs in the genomes of four Vitis species. A total of 35 horizontal transfer (HT) events were identified between the four Vitis species and 21 other plant species belonging to 14 different families. We determined the donor and recipient species for 28 of these HTs, with the Vitis species being recipients of 15 of them. As a result of HTs, 8–10 LTR retrotransposon clusters were newly formed in the genomes of the four Vitis species. The activities of the horizontally acquired LTR retrotransposons differed among Vitis species, showing that the consequences of HTs vary during the diversification of the recipient lineage. Our study provides the first evidence that the HT of TEs contributes to the diversification of plant genomes by generating additional TE subfamilies and causing their differential proliferation in host genomes. 相似文献
999.
A. I. Ul’yanov A. A. Chulkina V. A. Volkov E. P. Elsukov A. V. Zagainov A. V. Protasov I. A. Zykina 《The Physics of Metals and Metallography》2012,113(12):1134-1145
Using X-ray diffraction analysis, M?ssbauer spectroscopy, and magnetic measurements, the structure, parameters of hyperfine interactions, localization of Mn atoms in the lattice, coercive force, and specific saturation magnetization have been investigated in the mechanically alloyed and annealed cementite (alloyed with manganese) of compositions (Fe1 ? x Mn x )3C (x = 0?C0.12). It has been shown that strongly deformed cementite resides in the low-coercivity state and, after annealing in the vicinity of 500°C, in the high-coercivity state. Alloying with manganese reduces the coercive force, the specific saturation magnetization, and the Curie temperature of cementite. Inhomogeneities of the distribution of manganese atoms indicate the temperature dependence of the coercive force of mechanically alloyed and annealed cementite samples. 相似文献
1000.
The optimized plating bath composition (mol%) of 0.47NiCl2:0.23NaH2PO2:0.13C4H4Na2O4:3.47NaCl:95.70H2O produced Ni-P films with ~ 10 wt.% P at 85 °C over copper and steel substrates. The presence of chloride ions (Cl−) in the plating solution was found to facilitate initial deposition without any need of surface activation. Film growth rates as high as 7-8 μm/h were achieved with minimal or no deposition on surfaces other than the substrates. Scanning electron microscope (SEM) and atomic force microscope (AFM) studies revealed cauliflower-like morphology with submicron size grains. Increasing the amount of reducing agent increased film smoothness and refined grain size with corresponding increase in P content. X-ray diffraction studies of the deposit revealed semi-crystalline nature of the film which underwent transition to fully crystalline form upon heat treatment with an associated increase in average HK value from ~ 390 to 807 HK. High temperature provided driving force for surface and volume diffusion that subsequently led to reduced porosity and more homogeneous composition through rearrangement of atoms to form certain NixPy phases. Acid etching of the deposits transformed shiny films into matte black surfaces due to preferential removal of nickel leading to formation of porous structure with stalagmite-like morphology. 相似文献