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A carbonyl‐assisted asymmetric 1,2‐migratory allylation through in situ generation of vicinal tetrasubstituted stereocenters is reported to access enantiopure α‐amino ketones and amino alcohols with excellent yields and diastereoselectivities. In a remarkable divergence, despite higher steric hindrance, the allylation exclusively occurs on ketones over imines in the first step, followed by a face‐selective 1,2‐allyl transfer, thus highlighting an exciting interplay between two distinct electrophiles. The methodology distinguishes itself through its adaptability to gram‐scale synthesis, showcasing broad functional‐group tolerance and stereodivergence. Density functional theory (DFT) analysis led to a deeper understanding of its selectivity and mechanistic framework. Highlighting its transformative potential, the method was applied to the total synthesis of hapalindole alkaloids. [ABSTRACT FROM AUTHOR]

Among the natural ecosystems, forests and wetlands emit a sizable amount of carbon dioxide (CO2) and methane (CH4) through autotrophic and heterotrophic respiration and bacterial activities. Interestingly, some evidence suggests that a significant amount of CH4 is generated by the trees in forested ecosystems. The net ecosystem exchange (NEE), measured by the eddy covariance (EC) method, typically represents the net CO2 flux arising from the photosynthetic and respiration processes in the biosphere. This flux is subsequently partitioned into two components, the respired carbon and the assimilated carbon. However, the usual method of partitioning introduces significant errors in each of these fluxes. The present study was undertaken to address this issue where the NEE partitioning was constrained by using the carbon isotopic ratios of CO2. We used a real‐time in situ analyzer in a tropical forest in northeast India, the Kaziranga National Park. The greenhouse gas analyzer provided CO2 and CH4 concentrations, as well as their carbon isotopic ratios. The isotopic data were used to partition the EC‐derived NEE values and derive the isoflux values. Additionally, the isotopic data provided evidence of plant‐generated CH4 in conformity with some recent studies, which requires further investigation. Plain Language Summary: The terrestrial vegetation absorbs a vast amount of carbon in the photosynthetic process. They also emit a sizeable amount of carbon through respiration. Eddy‐covariance‐based technique is often employed to quantify these two opposing fluxes. An eddy‐covariance‐based system measures carbon dioxide (CO2) concentrations along with wind speed, and covariance of their fluctuations is used to calculate the net ecosystem exchange (NEE). The NEE is then partitioned into the photosynthetic and respiration components through a series of numerical operations and environmental constraints. Flux measurements in association with carbon isotopic ratios can provide a unique way to partition NEE. We have measured the concentration and isotopic ratio of CO2 and the eddy covariance‐based measurements to obtain the respiratory and photosynthetic fluxes of CO2 in a tropical forest in India. In addition, methane (CH4) concentration and its isotopic ratio have been measured to identify if trees can be considered a CH4 source in this ecosystem. Key Points: The net ecosystem exchange was measured using an eddy‐covariance technique in a forest in IndiaSeparately the greenhouse gases isotopic data were collected and used to determine the "isofluxes"Partitioning of the respiratory and the photosynthetic fluxes was carried out [ABSTRACT FROM AUTHOR]

The presence of nitrogen atom in a wide variety of organic compounds called for the use of powerful C−H activation strategy in the C−N bond formation. Pentamethylcyclopentadienyl (Cp*) based, high‐valent, group 9 transition‐metal complexes have shown a great potential as catalysts in the C−H activation/functionalization over the years. This minireview summarizes recent progress made in the context of C−N bond formation via catalytic (sp2)C−H activation with Cp*M(III) (M=Co, Rh and Ir) catalysts. A general plausible mechanism is briefly discussed at the beginning, and then results are arranged according to metal cobalt, rhodium and iridium, respectively. [ABSTRACT FROM AUTHOR]

A study has been performed to extract the unknown parameters of a photovoltaic (PV) module using mathematical model‐driven analysis. Neglecting the less significant terms, the number of non‐linear exponential terms are reduced to develop a simplified algorithm to estimate five unknown parameters such as diode ideality factor, series resistance, shunt resistance, diode saturation current and photogenerated current of a single diode model PV module accurately with less computational complexities from the manufacturer's datasheet values. Substituting the estimated values of the unknown parameters, the PV module output power is obtained at different irradiance and temperature, which shows close co‐ordination with the datasheet values. To improve the accuracy in the estimation of the PV module output using the proposed model, the nominal operating cell temperature (NOCT) is considered. The results of the proposed model are verified with the experimental output of two (one 315 Wp and another 3 Wp) PV modules, which shows better correlation with the proposed model considering NOCT. The measurement uncertainty to obtain the output power experimentally is not more than 6.88%. [ABSTRACT FROM AUTHOR]

There has been a tremendous evolution for artificial ion transport systems, especially gated synthetic systems, which closely mimic their natural congeners. Herein, we demonstrate a trans‐azobenzene‐based photoregulatory anionophoric system that transports chloride by forming a sandwich dimeric complex. Further studies confirmed a carrier‐mediated chloride‐anion antiport mechanism, and the supramolecular interactions involved in chloride recognition within the sandwich complex were revealed from theoretical studies. Reversible trans–cis photoisomerization of the azobenzene was achieved without any significant contribution from the thermal cis→trans isomerization at room temperature. Photoregulatory transport activity across the lipid bilayer membrane inferred an outstanding off‐on response of the azobenzene photoswitch. [ABSTRACT FROM AUTHOR]

Estimation of the output power of a solar photovoltaic (PV) system during partial shading condition (PSC) is an interest of PV installers. Owing to the inclusion of a bypass diode, the occurrence of local and global maximum peak creates more difficulty in the calculation of maximum power output from a PV array. In this study, a mathematical model is established to estimate the percentage of degradation of a square total cross tied (TCT) connected PV array at different PSCs. By employing the proposed algorithm, it will be easier to estimate the maximum power point of a m×n (m=n) TCT connected PV array during PSC without using any measuring instrument except for the measurement of irradiance and temperature. A better correlation is obtained when the output of the proposed model is compared with MATLAB simulated output. The output of the proposed model is compared with the experimental output performed on an array comprises of 3 W PV modules and the comparison shows the satisfactory result. [ABSTRACT FROM AUTHOR]

ZnO-silicon heterojunction solar cell having high efficiency and high fill factor is structured and simulated to study its photovoltaic properties under different device temperature. Current-voltage measurement of dimensionally optimised device structure revealed up to 20.44% efficiency and 83.66% fill factor at 1 ν-cm2 external series resistance at 300 K. Measured current-voltage shows decrease of open-circuit voltage from 659.13 to 109.1 mV and short-circuit current from 40.65 to 39.5 mA/cm2 with increase of device temperature. Quasi-steady-state photoconductance measurement reveals small recombination current and long Shockley Read Hall lifetime under the selected temperature range indicating superior performance of the device. Adverse effect of surface recombination velocity at rear surface of the device is observed at lower temperature (100-600 K) range indicating better majority carrier collection at very high temperature 700 K and above. [ABSTRACT FROM AUTHOR]

ABSTRACT: This study explores the possible causes of rainfall distribution over the two major oceanic raining regions of the north Bay of Bengal (nBoB) and the east equatorial Indian Ocean (eEIO). Despite 17% difference in vertically averaged humidity, there is almost 34% difference in mean rainfall over these two regions. The climatological seasonal [June–September (JJAS)] mean (standard deviation) rainfall over nBoB region is always higher (lower) than that over the eEIO region in all the independent data used. The eEIO region has a much larger percentage of low stratiform and convective rainfall (<5 mm day−1) distribution as compared to nBoB, which is totally opposite in case of moderate stratiform and convective rainfall (>5 mm day−1) distribution. This is further substantiated by a much lower values of outgoing long‐wave radiation (OLR) in nBoB (<200 W m−2) as compared to the eEIO (217 W m−2) region. Mean Hadley circulation along with relative vorticity/divergence profile supports more intense (gentle) updrafts over nBoB (eEIO) region. Latent heat (LH) is almost three times at the upper level (∼8 km) in case of nBoB as compared to eEIO; however, at the lower level (∼3 km) LH is marginally higher over eEIO region. Microphysical variables, namely cloud ice optical thickness and cloud ice water path, are in much larger quantities over nBoB as compared to eEIO. Furthermore, the cold (warm) rain processes dominate among other microphysical processes over nBoB (eEIO) region. Thus, the interplay among large‐scale dynamics, thermodynamics and microphysics is very crucial in the formation of deep clouds and convective rain over the nBoB region and similarly shallow clouds and stratiform rain over the eEIO region. This study will be very useful to guide present‐day coupled models for proper representation of different rain components over the nBoB and eEIO region. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the protective effect of ferulic acid at different doses (50 mg kg−1 alternative day and 50 mg kg−1 daily) on the streptozotocin (STZ)-induced post-diabetes rat testicular damage. Diabetes was induced by a single intraperitoneal injection of STZ (50 mg/kg). Rats treated with ferulic acid were given once a day orally for 10 weeks, starting 3 days after STZ injection. Testis tissue and blood samples were collected for investigating biochemical analysis, antioxidant status, sperm parameters, and histopathological, immunohistochemical and apoptotic studies. Treatment with ferulic acid to diabetic rats significantly improved the body weight, testis weight, serum insulin level, serum testosterone level and sperm parameters (viability, motility and count). Histopathological study also revealed that ferulic acid-treated diabetic rats showed an improved histological appearance. Our data indicated that significant reduction in the activity of apoptosis by using terminal deoxyuridine triphosphate nick end-labelling and reduced expression of transforming growth factor- β1 and interleukin-1 β in the testis tissue of ferulic acid-treated diabetic rats. Conversely, it was also revealed that ferulic acid-treated diabetic rats markedly enhanced the serine/threonine protein kinase protein expression in the testis tissue. Our result suggests that ferulic acid inhibits testicular damage in diabetic rats by declining oxidative stress. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]