Gilman reagent toward the synthesis of natural products.

With the ever-increasing scope of organocuprates, a well-established Gilman reagent has been considered as an unprecedented synthetic tool in modern organic chemistry. The broad research profile of the Gilman reagent (R2CuLi in THF or Et2O) is owing to its propensity to carry out three kinds of reactions, i.e., epoxide ring opening reactions, 1,4-conjugate addition reactions, and SN2 reactions in a regioselective manner. This review examines the applications of Gilman reagent in the total synthesis of both abundant and scarce natural products of remarkable synthetic pharmaceutical profile reported since 2011. The presented insights will be of a vital roadmap to general organic synthesis and it will contribute to the development of new natural products and their analogues in future drug discovery.

Memory-type variance estimators using exponentially weighted moving average statistic in presence of measurement error for time-scaled surveys.

The present study suggested memory-type ratio and product estimators for variance estimation in the presence of measurement errors. We applied the exponentially weighted moving averages statistic which simultaneously utilizes the current and prior information for better estimation in surveys based on the time-scale. The expressions of approximate mean square errors of memory-type estimators are derived using Taylor series up to first order. Mathematical conditions are also obtained for which the suggested memory-type ratio and product estimators perform better than the conventional ratio and product estimators. The efficiency of the proposed estimators is observed using an extensive simulation study in the presence of measurement errors. A real data application is also carried out to support the mathematical expressions. From the results, it is shown that the use of prior sample information significantly increased the efficiency of the proposed estimators.

Laser flash photolysis study of Nb2O5/g-C3N4 heterostructures as efficient photocatalyst for molecular H2 evolution.

Improvements of visible light activity, slow recombination rate, stability, and efficiency are major challenges facing photocatalyst technologies today. Utilizing heterostructures of g-C3N4 (bandgap ∼2.7eV) with Nb2O5 (bandgap ∼3.4eV) as an alternative materials for the first time, we tried to overcome such challenges in this work. Heterostructures of Nb2O5/g-C3N4 have been synthesized via hydrothermal technique. And then a time-resolved laser flash photolysis of those heterostructures has been analyzed, focusing on seeking how to improve photocatalytic efficiency for molecular hydrogen (H2) evolution. The transient absorption spectra and the lifetime of charge carriers at different wavelengths have been observed for Nb2O5/g-C3N4, where g-C3N4 was used for a control. The role of hole scavenger (methanol) has also been investigated for the purpose of boosting charge trapping and H2 evolution. The long lifetime of Nb2O5/g-C3N4 heterostructures (6.54165 µs) compared to g-C3N4 (3.1651897 µs) has successfully supported the increased H2 evolution of 75 mmol/h.g. An enhancement in the rate of H2 evolution (160 mmol/h.g) in the presence of methanol has been confirmed. This study not only deepens our understanding of the role of scavenger, but also enables a rigorous quantification of the recombination rate crucial for photocatalytic applications in relation with efficient H2 production.

Role of Human Papillomavirus in Various Cancers: Epidemiology, Screening and Prevention.

It is estimated that viral infections contribute 15-20% of all human cancers. Several types of human papillomaviruse (HPV) are related to the development of many cancer types and their treatment. About 200 HPV viruses have been identified, and each type of virus is integrated with a certain type of clinical lesions affecting the areas of skin and mucous membranes. Infections associated with HPV are known to cause multiple cancer types such as uterine cancer, cervical, vaginal carcinoma, and other varieties of carcinomas such as genital and oropharyngeal, penile, and short-lived carcinomas. Most of the HPV types are considered as high-risk mutants that can provoke cervical cancer in females in addition to significant contribution to other cancer types such as anogenital cancer and tumor in head and neck regions. Among them, high risk human papilloma viruses (HR-HPV) subtypes 16 and 18 play a major role in the etiology of cervical cancer worldwide. Although, cervical cancer incidence and fatality rates vary greatly depending on geographical area, it is the leading cause of mortality in women around the world. In addition, it is epidemiologically similar to a sexually transmitted disease of low infectivity. In this review article, the association of HPV with different types of cancers have been explained, but the main focus remains on cervical cancer.

Ex Situ Synthesis and Characterizations of MoS2/WO3 Heterostructures for Efficient Photocatalytic Degradation of RhB.

In this study, novel hydrothermal ex situ synthesis was adopted to synthesize MoS2/WO3 heterostructures using two different molar ratios of 1:1 and 1:4. The "bottom-up" assembly was successfully developed to synthesize spherical and flaky-shaped heterostructures. Their structural, morphological, compositional, and bandgap characterizations were investigated through XRD, EDX, SEM, UV-Visible spectroscopy, and FTIR analysis. These analyses help to understand the agglomerated heterostructures of MoS2/WO3 for their possible photocatalytic application. Therefore, prepared heterostructures were tested for RhB photodegradation using solar light irradiation. The % efficiency of MoS2/WO3 composites for 30 min irradiation of 1:1 was 91.41% and for 1:4 was 98.16%. Similarly, the % efficiency of 1:1 MoS2/WO3 heterostructures for 60 min exposure was 92.68%; for 1:4, it was observed as 98.56%; and for 90 min exposure, the % efficiency of 1:1 was 92.41%, and 98.48% was calculated for 1:4 composites. The photocatalytic efficiency was further verified by reusability experiments (three cycles), and the characterization results afterward indicated the ensemble of crystalline planes that were responsible for the high efficiency. Moreover, these heterostructures showed stability over three cycles, indicating their future applications for other photocatalytic applications.