Computer Simulation of the Electric Transport Properties of the FeSe Monolayer

The paper deals with the model research of electric transport characteristics of stressed and non-stressed FeSe monolayers. Transmission spectra, current-voltage characteristic (CVC) and differential conductivity spectra of two-dimensional FeSe nanostructure have been calculated within the framework of the density functional theory and non-equilibrium Green’s functions (DFT + NEGF). It has been shown that the electrophysical properties depend on the geometry of the sample, the substrate, and the lattice constant. On CVC of non-stressed sample in the range from −1.2 V to −1 and from 1.2 V to 1.4 V, a region of negative differential resistance (NDR) has been observed. NDR is at both signs of the applied voltage due to the symmetry of the nanostructure. d2I/dV2 is used to determine the nature of the electron-phonon interaction and the features of quasiparticle tunnelling in stressed and non-stressed samples. The results obtained can be useful for calculating new elements of 2D nanoelectronics.

Transcriptomic Analysis Revealed the Common and Divergent Responses of Maize Seedling Leaves to Cold and Heat Stresses

Temperature stresses (TS), including cold and heat stress, adversely affect the growth, development, and yield of maize (Zea mays L.). To clarify the molecular mechanisms of the tolerance of maize seedling leaves to TS, we applied transcriptomic sequencing of an inbred maize line, B73, with seedlings exposed to various temperature conditions, including normal temperature (NT, 25 °C), cold (4, 10, and 16 °C), and heat (37, 42, and 48 °C) stresses. Differentially expressed genes (DEGs) were detected in different comparison between the NT sample and each temperature-stressed sample, with 5358, 5485, 5312, 1095, 2006, and 4760 DEGs responding to TS of 4, 10, 16, 37, 42, and 48 °C, respectively. For cold and heat stresses, 189 DEGs enriched in the hydrogen peroxidase metabolic process, cellular modified amino acid metabolic process, and sulfur compound metabolic process were common. The DEGs encoding calcium signaling and reactive oxygen species scavenging enzymes demonstrated similar expression characterizations, whereas the DEGs encoding transcription factors, such as ERF, ARF, and HSF, hormone signaling, and heat shock proteins, displayed divergent expression models, implying both common and divergent responses to cold and heat stresses in maize seedling leaves. Co-expression network analysis showed that functional DEGs associated with the core regulators in response to cold and heat stresses were significantly correlated with TS, indicating their vital roles in cold and heat adaptation, respectively. Our investigation focused on the response to gradient TS, and the results presented a relatively comprehensive category of genes involved in differential TS responses. These will contribute a better understanding of the molecular mechanisms of maize seedling leaf responses to TS and provide valuable genetic resources for breeding TS tolerant varieties of maize.

STABILITY INDICATING RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF PIOGLITAZONE, AMLODIPINE, ATORVASTATIN AND CLOPIDOGREL

A new simple, rapid, isocratic and stability indicating reverse phase high performance liquid chromatography (HPLC) method has been developed for simultaneous estimation of pioglitazone (P), amlodipine (AM), atorvastatin (AT) and clopidogrel (CP). Isocratic separation was achieved on Millennium M Sil C18 (125 mm ´4.6 mm) column, with mobile phase comprising of methanol: 0.02 M KH2PO4 (55:45 V/V), pH adjusted 4.0 with 0.01% ortho phosphoric acid. The flow rate was maintained 1mL/min and analytes were screened with U.V. detector. The method was validated according to ICH guidelines with respect to linearity, accuracy, precision and specificity. The drugs were exposed to various stress conditions like acidic and basic hydrolysis, oxidation, exposure to UV light and temperature (dry heat) and the stressed sample were analysed by the proposed method. No co-eluting, interfering peaks from excipients, impurities were observed during stress condition and all the degraded peaks are well resolved from parent peaks.

STABILITY INDICATING ASSAY METHOD OF SIROLIMUS USING HPLC AND SEPARATION OF ACID DEGRADANT BY HPTLC

A stability indicating RP-HPLC method has been developed and subsequently validated for Sirolimus. The proposed RP-HPLC method utilizes Phenomenex, C18, 3 μm, 4 mm x 150 mm column, mobile phase consisting of acetonitrile and water (65:35 V/V) and UV detection at 277 nm using a photodiode array detector in the stressed sample chromatograms. Crushed sirolimus tablets were exposed to thermal, photolytic, aqueous and oxidation stress conditions and stressed samples were analysed by the proposed method. Peak homogeneity data of the drug peaks were obtained using photodiode array detector. The stressed sample chromatograms demonstrated the specificity of the method for their estimation in presence of degradants. 99.66% degradation was observed in acid degradation study. on the other hand, no degradation was observed in aqueous condition. The given method was linear over a range of 0.1566 mg/mL to 0.4699 mg/mL. The mean recovery was found to be 99.23%. Acid degradant was separated by HPTLC and spectroscopic analysis was performed for the same.

Directional asymmetry estimates developmental instability in plants: A case report in Plantago major L. leaves

In the present study, an additional approach was used to evaluate the potential effects of the industrial development on natural population of the common plantain (Plantago major L.), previously estimated using si2 as an index of fluctuation asymmetry (FA) together with the coefficient of variation (CV). In this study, directional asymmetry (DA), a form of asymmetry in bilaterally symmetric traits, was used in order to estimate its rule as a potential indicator of developmental instability in leaf traits. Obtained results shows significantly higher DA values for the vein distances within a leaf (VD) on environmentally stressed area than in the control site. Reporting significantly higher values of DA for VD on the environmentally stressed sample and a positive relationship between FA and CV values obtained for the same trait within the same site, in a previous study, the study corroborates the potential of DA as an indicator of developmental perturbations.

Machining of simulated defects in pipeline steels: A neutron diffraction study of local stress effects

The most commonly used in-line pipeline inspection tools utilize the magnetic flux leakage (MFL) technique, which is sensitive to the stress state of the pipe wall. Calibration of these MFL tools is often carried out using unstressed pipeline sections containing simulated defects, usually produced by mechanical drilling. There is also strong interest in creating simulated defects in stressed pipe walls, thus simulating corrosion in the field. In this study, neutron diffraction is used to map the local stresses surrounding mechanically and electrochemically drilled holes in a steel plate sample. Holes were drilled in unstressed samples, as well as samples held at a constant 80 MPa uniaxial stress. Mechanical drilling into a stressed sample was found to induce considerable residual stresses around the hole. Conversely, electrochemical drilling did not create a residual stress field in the vicinity of the hole.