Intrinsic and Strain-Dependent Properties of Suspended WSe₂ Crystallites toward Next-Generation Nanoelectronics and Quantum-Enabled Sensors

Two-dimensional (2D) layered materials exhibit great potential for high-performance electronics, where knowledge of their thermal and phononic properties is critical toward understanding heat dissipation mechanisms, considered to be a major bottleneck for current generation nanoelectronic, optoelectronic, and quantum-scale devices. In this work, noncontact Raman spectroscopy was used to analyze thermal properties of suspended 2D WSe2 membranes to access the intrinsic properties. Here, the influence of electron–phonon interactions within the parent crystalline WSe2 membranes was deciphered through a comparative analysis of extrinsic substrate-supported WSe2, where heat dissipation mechanisms are intimately tied to the underlying substrate. Moreover, the excitonic states in WSe2 were analyzed by using temperature-dependent photoluminescence spectroscopy, where an enhancement in intensity of the localized excitons in suspended WSe2 was evident. Finally, phononic and electronic properties in suspended WSe2 were examined through nanoscale local strain engineering, where a uniaxial force was induced on the membrane using a Au-coated cantilever within an atomic force microscope. Through the fundamental analysis provided here with temperature and strain-dependent phononic and optoelectronic properties in suspended WSe2 nanosheets, the findings will inform the design of next-generation energy-efficient, high-performance devices based on WSe2 and other 2D materials, including for quantum applications

Total Utilization of Miscanthus Biomass, Lignin and Carbohydrates, Using Earth Abundant Nickel Catalyst

Lignin as a polymer of monomeric aromatic compounds retains great potential to be a source for liquid fuels and valuable chemicals. However, lignin from biomass has been traditionally treated as a waste byproduct and in most applications burned for its heat value. In this work, we report the catalytic conversion of lignin in Miscanthus into aromatic products by using earth-abundant Ni catalyst supported on activated carbon, under relatively mild conditions. The special ferulate linkage in grasses gives methyl ferulate ester and its derivatives, which were not observed for wood biomass substrates. By modification of the reaction conditions, saturated or unsaturated branched products can be obtained selectively. Optimal conditions give over 68% yield of select aromatic products from lignin. Furthermore, after lignin depolymerization and upgrading, the carbohydrates of miscanthus were recovered as a solid residue, which upon treatment with iron chloride produced useful platform chemicals (furfurals and levulinic acid). On the basis of our study, all three major components of biomass (lignin, cellulose and hemicellulose) are effectively utilized, with an overall 55% conversion of total accessible biomass into high value chemicals with 98% mass balance

Mechanism of Me–Re Bond Addition to Platinum(II) and Dioxygen Activation by the Resulting Pt–Re Bimetallic Center

Unusual cis-oxidative addition of methyltrioxorhenium (MTO) to [PtMe₂(bpy)], (bpy = 2,2′-bipyridine) (<b>1</b>) is described. Addition of MTO to <b>1</b> first gives the Lewis acid–base adduct [(bpy)­Me₂Pt–Re­(Me)­(O)₃] (<b>2</b>) and subsequently affords the oxidative addition product [(bpy)­Me₃PtReO₃] (<b>3</b>). All complexes <b>1</b>, MTO, <b>2</b>, and <b>3</b> are in equilibrium in solution. The structure of <b>2</b> was confirmed by X-ray crystallography, and its dissociation constant in solution is 0.87 M. The structure of <b>3</b> was confirmed by extended X-ray absorption fine structure and X-ray absorption near-edge structure in tandem with one- and two-dimensional NMR spectroscopy augmented by deuterium and ¹³C isotope-labeling studies. Kinetics of formation of compound <b>3</b> revealed saturation kinetics dependence on [MTO] and first-order in [Pt], complying with prior equilibrium formation of <b>2</b> with oxidative addition of Me–Re being the rate-determining step. Exposure of <b>3</b> to molecular oxygen or air resulted in the insertion of an oxygen atom into the platinum–rhenium bond forming [(bpy)­Me₃PtOReO₃] (<b>4</b>) as final product. Density functional theory analysis on oxygen insertion pathways leading to complex <b>4</b>, merited on the basis of Russell oxidation pathway, revealed the involvement of rhenium peroxo species

Results of multivariate analysis.

<p>OR: odds ratio; CI: confidence interval; BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressures; Hb:hemoglobin; SCr: serum creatinine; ALB: albumin.</p

Results of univariate analysis.

<p>BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; Hb:hemoglobin; SCr: serum creatinine; ALB: albumin.</p

Analysis of clinical bleeding & thromboembolic events within the two years.

<p>Values are shown as the Number of bleeding (or thromboembolic) events/the number of the patients of the group, (percentage). OR: odds ratio; CI: confidence interval.</p

MHD patients and healthy controls characteristics according to baseline status.

<p>BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; Hb:hemoglobin; SCr: serum creatinine; ALB: albumin.</p

The baseline-factor analysis between the patients with continued dialysis and death.

<p>OR: odds ratio; CI: confidence interval; BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressures; Hb:hemoglobin; SCr: serum creatinine; ALB: albumin.</p

Diagram of MHD patients and healthy controls.

<p>The diagram shows the numbers of MHD patients and healthy controls who met the criteria of inclusion in or exclusion from the study and the follow-up of the MHD patients.</p