Cu(I)-mediated deoxygenation of N-oxides to amines

A mild and highly efficient deoxygenation of variety of N-oxides using an inexpensive CuX, or a CuX-Zn or CuX-Al couple is described.     

Characterization of wafer-scale MoS2 and WSe2 2D films by spectroscopic ellipsometry

Here, we present the spectroscopic ellipsometry investigation of synthetically grown wafer-scale two-dimensional (2D) MoS₂ and WSe₂ films to access quality and thickness uniformity. MoS₂ and WSe₂ samples were grown by chemical vapor deposition and atomic layer deposition, respectively. Complex dielectric function ($\epsilon ={\epsilon }_1+i{\epsilon }_2$) and thickness information of these 2D films were extracted from the measured data using multilayer optical calculations. Broad spectral range (1.2–6 eV) and multiple angles of incidence were used to reduce correlations among fitting parameter. Lineshape of ε of MoS₂ and WSe₂ monolayer films are consistent with literature but shows higher values, suggests better quality of our samples. Eight-inch wafer size MoS₂ monolayer sample shows ～ 70% uniformity with an average thickness of 0.65 ± 0.2 nm, and three-layer WSe₂ sample of 8 × 1 cm² area shows ～ 80% uniformity with an average thickness of 2.5 ± 0.4 nm. Our results will be helpful to accelerate commercialization process of 2D devices.     

Frequency response of a synthetic jet cavity

A synthetic jet results from periodic oscillations of a diaphragm in a cavity. We present the results of a detailed experimental investigation wherein the effect of excitation frequency on the synthetic jet flow is studied for cavities of different depths and for orifices of different diameters. The exit velocity averaged over an excitation cycle indicates a lower and an upper bound on the frequency for the formation of a jet, and shows resonance at two frequencies. The resonant frequencies have been identified as being close to the diaphragm and the Helmholtz frequencies, with the former being more important in the present set of experiments. We discuss approaches to manipulate these frequencies from the point of view of cavity design. Interestingly, the input power is found to be at a minimum at the diaphragm frequency. Our measurements over a relatively large parameter domain suggest that the turbulence intensity in the near field is independent of the cavity depth and excitation frequency, but depends on the orifice diameter. These results are expected to be useful for designing synthetic jet cavity.     

The role of magnetic resonance spectroscopy in clinical medicine

This article presents a view which emphasises the particular perspective of a clinician who has close involvement in magnetic resonance spectroscopy (MRS) and is directed towards readers who wish to understand the likely role of MRS in clinical medicine. Many more complete reviews already exist, including two review articles from our group. Another review would hardly be justifiable and those readers seeking such an article should consult Refs. 1–5. This will be more in the nature of a personal overview of the topic and one which will touch upon some of the problems which accrue from the interactions of scientists with little appreciation of clinical medicine with clinicians who have little understanding of the complexities of the NMR experiment. Moreover, the discussion will be confined to situations where MRS is likely to impinge directly on problems of day-to-day clinical management, as opposed to situations where the results of MRS research lead to an improved understanding of particular disease states, but where there is no need for each and every patient who is a potential benificiary of the technique to undergo an MRS examination.     

Single Conducting Polymer Nanowire Based Sequence‐Specific,Base‐Pair‐Length Dependant Label‐free DNA Sensor

We have fabricated a highly sensitive, simple and label‐free single polypyrrole (Ppy) nanowire based conductometric/chemiresistive DNA sensor. The fabrication was optimized in terms of probe DNA sequence immobilization using a linker molecule and using gold‐thiol interaction. Two resultant sensor designs working on two different sensing mechanisms (gating effect and work function based sensors) were tested to establish reliable sensor architecture with higher sensitivity and device‐to‐device reproducibility. The utility of the work function based configuration was demonstrated by detecting 19 base pair (bp) long breast cancer gene sequence with single nucleotide polymorphism (SNP) discrimination with high sensitivity, lower detection limit of ∼10⁻¹⁶ M and wide dynamic range (∼10⁻¹⁶ to 10⁻¹¹ M) in a small sample volume (30 µL). To further demonstrate the utility of the DNA sensor for detection of target sequences with different number of bases, targets with 21 and 36 bases were detected. These sequences have implications in environmental sample analysis or metagenomics. Sensor response showed increase with the number of bases in the target sequence. For long sequence (with 36 bases), effect of DNA alignment on sensor performance was studied.     

The role of pore size and structure on the thermal stability of gold nanoparticles within mesoporous silica

Highly dispersed gold particles (<2 nm) were synthesized within the pores of mesoporous silica with pore sizes ranging from 2.2 to 6.5 nm and different pore structures (2D-hexagonal, 3D-hexagonal, and cubic). The catalysts were reduced in flowing H2 at 200 degrees C and then used for CO oxidation at temperatures ranging from 25 to 400 degrees C. The objective of this study was to investigate the role of pore size and structure in controlling the thermal sintering of Au nanoparticles. Our study shows that sintering of Au particles is dependent on pore size, pore wall thickness (strength of pores), and pore connectivity. A combination of high-resolution TEM/STEM and SEM was used to measure the particle size distribution and to determine whether the Au particles were located within the pores or had migrated to the external silica surface.     

Identification of dual Acetyl-CoA carboxylases 1 and 2 inhibitors by pharmacophore based virtual screening and molecular docking approach

Acetyl-CoA carboxylase (ACC) is a crucial metabolic enzyme that plays a vital role in obesity-induced type 2 diabetes and fatty acid metabolism. To identify dual inhibitors of Acetyl-CoA carboxylase1 and Acetyl-CoA carboxylase2, a pharmacophore modelling approach has been employed. The best HypoGen pharmacophore model for ACC2 inhibitors (Hypo1_ACC2) consists of one hydrogen bond acceptor, one hydrophobic aliphatic and one hydrophobic aromatic feature, whereas the best pharmacophore (Hypo1_ACC1) for ACC1 consists of one additional hydrogen-bond donor (HBD) features. The best pharmacophore hypotheses were validated by various methods such as test set, decoy set and Cat-Scramble methodology. The validated pharmacophore models were used to screen several small-molecule databases, including Specs, NCI, ChemDiv and Natural product databases to identify the potential dual ACC inhibitors. The virtual hits were then subjected to several filters such as estimated $\text{ IC}_{50}$ value, quantitative estimation of drug-likeness and molecular docking analysis. Finally, three novel compounds with diverse scaffolds were selected as potential starting points for the design of novel dual ACC inhibitors.