Asymptotic Solution of Linear Bisingular Problems With Additional Boundary Layer

We study two bisingular Dirichlet problem with the additional boundary layer: 1) for the second order linear elliptic equation in a ring, 2) for linear ordinary differential equations of second order in a segment. We construct asymptotic solutions to the three-zone, bisingular Dirichlet problems by using the generalized method of boundary functions and obtain estimates for the residual functions.     

Influence of deposition conditions on the antireflection properties of diamond-like carbon films for Si-based solar cells

The influence of deposition conditions on the antireflection properties of diamond-like carbon films for Si-based solar cells is studied theoretically. The values of the short-circuit current density for Si solar cells covered by diamond-like carbon films deposited at different concentrations of nitrogen in the gas mixture are calculated and compared with the associated values for uncovered solar cells. It is shown that the short-circuit current density increases with nitrogen concentration in the gas mixture because of a lower light absorption by the growing film. Optimum thicknesses of the diamond-like carbon films are calculated that provides a maximal increase in the output short-circuit current density of Si-based solar cells under both AM1.5 and AM0 conditions. Published in Russian in Zhurnal Tekhnicheskoĭ Fiziki, 2006, Vol. 76, No. 5, pp. 122–126. The article was translated by the authors.     

Integrating Pharmacological and Computational Approaches for the Phytochemical Analysis of Syzygium cumini and Its Anti-Diabetic Potential

Diabetes mellitus (DM) is a metabolic disease caused by improper insulin secretion leading to hyperglycemia. Syzygium cumini has excellent therapeutic properties due to its high levels of phytochemicals. The current research aimed to evaluate the anti-diabetic potential of S. cumini plant’s seeds and the top two phytochemicals (kaempferol and gallic acid) were selected for further analysis. These phytochemicals were selected via computational tools and evaluated for α-Glucosidase inhibitory activity via enzymatic assay. Gallic acid (IC₅₀ 0.37 µM) and kaempferol (IC₅₀ 0.87 µM) have shown a stronger α-glucosidase inhibitory capacity than acarbose (5.26 µM). In addition, these phytochemicals demonstrated the highest binding energy, hydrogen bonding, protein–ligand interaction and the best MD simulation results at 100 ns compared to acarbose. Furthermore, the ADMET properties of gallic acid and kaempferol also fulfilled the safety criteria. Thus, it was concluded that S. cumini could potentially be used to treat DM. The potential bioactive molecules identified in this study (kaempferol and gallic acid) may be used as lead drugs against diabetes.     

Multifaced Assessment of Antioxidant Power,Phytochemical Metabolomics,In-Vitro Biological Potential and In-Silico Studies of Neurada procumbens L.: An Important Medicinal Plant

This work was undertaken to explore the phytochemical composition, antioxidant, and enzyme-inhibiting properties of Neurada procumbens L. extracts/fractions of varying polarity (methanol extract and its fractions including n-hexane, chloroform, n-butanol, and aqueous fractions). A preliminary phytochemical study of all extracts/fractions, HPLC-PDA polyphenolic quantification, and GC-MS analysis of the n-hexane fraction were used to identify the phytochemical makeup. Antioxidant (DPPH), enzyme inhibition (against xanthine oxidase, carbonic anhydrase, and urease enzymes), and antibacterial activities against seven bacterial strains were performed for biological investigation. The GC-MS analysis revealed the tentative identification of 22 distinct phytochemicals in the n-hexane fraction, the majority of which belonged to the phenol, flavonoid, sesquiterpenoid, terpene, fatty acid, sterol, and triterpenoid classes of secondary metabolites. HPLC-PDA analysis quantified syringic acid, 3-OH benzoic acid, t-ferullic acid, naringin, and epicatechin in a significant amount. All of the studied extracts/fractions displayed significant antioxidant capability, with methanol extract exhibiting the highest radical-scavenging activity, as measured by an inhibitory percentage of 81.4 ± 0.7 and an IC₅₀ value of 1.3 ± 0.3. For enzyme inhibition experiments, the n-hexane fraction was shown to be highly potent against xanthine oxidase and urease enzymes, with respective IC₅₀ values of 2.3 ± 0.5 and 1.1 ± 0.4 mg/mL. Similarly, the methanol extract demonstrated the strongest activity against the carbonic anhydrase enzyme, with an IC₅₀ value of 2.2 ± 0.4 mg/mL. Moreover, all the studied extracts/fractions presented moderate antibacterial potential against seven bacterial strains. Molecular docking of the five molecules β-amyrin, campesterol, ergosta-4,6,22-trien-3β-ol, stigmasterol, and caryophyllene revealed the interaction of these ligands with the investigated enzyme (xanthine oxidase). The results of the present study suggested that the N. procumbens plant may be evaluated as a possible source of bioactive compounds with multifunctional therapeutic applications.     

Correlation Between the Scaling Factor of the Yukawa Coupling and Cross Section for the e + e − → h h f f ¯ $e^{+} e^{-} \rightarrow hhf\overline {f}$ (f≠t) in Type-I 2HDM

International Journal of Theoretical Physics - The objective of this study is to correlate the scaling factor of the Standard Model (SM) like Higgs boson and the cross section ratio of the process...     

Biological and radiochemical quality control of indigenous99mTc-radiopharmaceutical kits

Biological and radiochemical quality control of indigenous (Pinscan) diagnostic cold kits of Methylene Diphosphonate (MDP), Tin-colloid and Diethylene Triamine Pentaacetic Acid (DTPA) was performed in parallel with imported Amersham's kits (Amerscan). The results of radiochemical purity, sterility, apyrogenicity and biodistribution of indigenous (Pinscan) kits were good and quantitatively and qualitatively comparable to those obtained with Amersham's (Amerscan) imported kits.     

Calculation driven synthesis of an excellent dihydropyrene negative photochrome and its photochemical properties

The photochromic properties of dihydropyrenes have been substantially improved by making use of density functional theory (DFT) activation barrier calculations, which suggested that the di-isobutenylcyclophanediene 15' should have a significant barrier to thermal isomerization to the dihydropyrene (DHP) 15, which itself should resist isomerization involving migration of the internal groups to the rearranged dihydropyrene 9 (X = -CH═C(Me)(2)). As a result of these calculations, the synthesis of the colorless cyclophanediene (CPD) 15' was undertaken and achieved from the dinitrile 28 in four steps in 37% overall yield %. The cyclophanediene 15' thermally isomerized to the dihydropyrene 15 at 100 °C with t(1/2) = 4.5 h, giving an extrapolated 20 °C t(1/2) of ～16 y, consistent with the DFT calculations. No evidence for [1,5]-sigmatropic rearrangement in to 9 (X = -CH═C(Me)(2)) was observed on heating to 130 °C. The ring-opening isomerization quantum yields (?(open)) for DHP 15 in to CPD 15' were determined in cyclohexane to be 0.12 ± 0.01, which is three times greater than for the benzoDHP 1. Friedel-Crafts naphthoylation of 15 gave 70% of purple 32, which in toluene showed the largest photochemical ring-opening isomerization quantum yields (?(open)) of 0.66 ± 0.02 for any known dihydropyrene, ～nine times greater than 1 in toluene. The thermal closing of 32' to 32, although faster than for 15', gave a useful extrapolated t(1/2) of ～2 y at 20 °C.     

Aromaticities of azines relative to benzene; a theoretical approach through the dimethyldihydropyrene probe

The aromaticities of azines relative to benzene have been estimated by fusion with 15,16‐dimethyldihydropyrene. Chemical shift data for the azine‐fused dihydropyrenes (calculated at GIAO HF/6‐31G*//B3LYP/6‐31 + G*) were used to estimate the reduction in the dihydropyrene nucleus aromaticity. Choice of the saturated reference model was quite crucial in reliable estimation of aromaticity. Reference models with partial unsaturation at azine (21,23,25–32) gave better estimate of aromaticity than the parent dimethyldihydropyrene. Aromaticities of azines through chemical shift data and geometric parameter analysis were found to be 90–100% to that of benzene, highly consistent with the aromaticity estimation by nucleus independent chemical shift_(0)πzz calculations. Copyright © 2014 John Wiley & Sons, Ltd.     

A simple,sensitive and rapid radiorespirometric estimation of soil enzymatic activity

A rapid, sensitive and automated radiorespirometric procedure utilizing¹⁴CO₂ production from¹⁴C-glucose has been used to measure the enzymatic activity of soil, reducing the assessment time of microflora in soil from many months to a few hours. The instrument used has been previously applied for detection of bacteria in blood. The lowest detection limit of the instrument is 0.00025 Ci or 9.25 Bq, the detection limit of instruments previously used in such studies was about three times higher.