Graphene/carbon nanotubes composites as a counter electrode for dye-sensitized solar cells

As an alternative platinum counter electrode in dye-sensitized solar cells (DSSCs), carbon materials based counter electrode were prepared using multi-walled carbon nanotubes (MWNTs)/graphene nano-sheets (GNS) composite by simple doctor blade method. We found that the photovoltaic performance was strongly influenced by the concentration of GNS in composite electrode. The composite electrode with 60% MWNTs and 40% GNS based DSSCs showed the maximum power conversion efficiency of 4.0% while sputter deposited platinum counter electrode based DSSCs showed a power conversion efficiency of 5.0%.     

ChemInform Abstract: A Three‐Dimensional Aromatic B6Li8 Complex as a High Capacity Hydrogen Storage Material.

On the basis of theoretical calculations (B3LYP/6‐311+G), the title complex is predicted to be aromatic and a promising hydrogen storage material with a gravimetric density of up to 24%.     

Lignans and Triterpenes from the Root of Pseuderanthemum carruthersii var. atropurpureum

Two new lignans, pseuderesinol (1), pseuderanoside (2) and a new triterpene, pseuderanic acid (3) were isolated from the dried root of Pseuderanthemum carruthersii (SEEM.) GUILL. var. atropurpureum (BULL.) FOSB. (Acanthaceae), together with ten known compounds, including five lignans, (+)-eudesmin (4), (+)-magnolin (5), (+)-syringaresinol (6), (+)-episyringaresinol (7), (+)-1-hydroxysyringaresinol (8) and five triterpenes, squalene (9), oleanolic acid (10), lupeol (11), betulin (12), betulinic acid (13). Their chemical structures were elucidated by 1D- and 2D-NMR, computational quantum chemistry, as well as high resolution-electrospray ionization (HR-ESI)-MS spectroscopic analysis. The acetylcholinesterase inhibition and cytotoxic activities against HeLa and MCF-7 cancer cell lines were evaluated on some purified compounds at the concentration of 100?μg/mL. Pseuderesinol (1) and magnolin (5) exhibited moderate cytotoxic activities against the MCF-7 cancer cell line.     

Polyamides with pendant 1,3,4-oxadiazole and pyridine moieties

A novel aromatic diamine,2-（5-（3,5-diaminophenyl）-l,3,4-oxadiazole-2-yl）pyridine（POBD）,containing a pyridine ring and a 1,3,4-oxadiazole moiety,was synthesized.It was used in a polycondensation with various aromatic and aliphatic diacid chlorides to generate a series of new aromatic polyamides with pendant 1,3,4-oxadiazole groups.The prepared polyamides were characterized by IR,elemental analysis and through the synthesis of model compounds.Thermophysical properties of the synthesized polyamides have been studied by DSC,TGA and inherent viscosity measurements. Relatively high inherent viscosity values（0.76-1.62 dL/g,in 0.125%H₂SO₄ at 25℃） were observed for these compounds. Number average molecular weight（M_n） of the polymers was measured by vapor phase osmometry（VPO）.The introduction of bulky side chains in the structure of aromatic polyamides led to increased solubility of these polymers in common polar and aprotic solvents,such as DMF,DMSO,NMP and DMAc,which allowed thin films to be cast from polymer solutions. The highest molecular weight（M_n = 51190） was observed for polymer（DC）,which was prepared from pyridine-2,6-dichlorocarbonyl.     

Identification of Non-Macrocyclic Small Molecule Inhibitors against the NS3/4A Serine Protease of Hepatitis C Virus through in Silico Screening

Drug discovery and design for inhibition of the Hepatitis C Virus (HCV) NS3/4A serine protease is a major challenge. The broad, shallow, and generally featureless nature of the active site makes it a difficult target for "hit" selection especially using standard docking programs. There are several macrocyclic NS3/4A protease inhibitors that have been approved or are in clinical trials to treat chronic HCV (alone or as combination therapy), but most of the current therapies for HCV infection have untoward side effects, indicating a continuing medical need for the discovery of novel therapeutics with improved efficacy. In this study, we designed and implemented a two-tiered and progressive docking regime that successfully identified five non-macrocyclic small molecules that show inhibitory activity in the low micromolar range. Of these, four compounds show varying inhibition against HCV subgenotypes 1b, 1a, 2a, and 4d. The top inhibitor (3) has an IC(50) value of 15 μM against both subgenotypes 1b and 2a of the NS3/4A protease enzyme. Another inhibitor, 1, inhibits all four subgenotypes with moderate activity, showing highest activity for genotype 2a (24 μM). The five inhibitors presented in this study could be valuable candidates for future hit to lead optimization. Additionally, enzyme-inhibitor interaction models presented herein provide key information regarding structural differences between the active sites of the NS3/4A protease of the HCV subgenotype 1a and 1b that might explain the variable inhibitory activity between subgenotypes of the small molecule inhibitors identified here.     

Rational aspect ratio and suitable antibody coverage of gold nanorod for ultra-sensitive detection of a cancer biomarker

We report a simple, ultra-sensitive, and straightforward method for non-labeling detection of a cancer biomarker, using Rayleigh light scattering spectroscopy of the individual nanosensor based on antibody-antigen recognition and localized surface plasmon resonance (LSPR) λ(max) shifts. By experimentally measuring the refractive index sensitivity of Au nanorods, the Au nanorod with an aspect ratio of ~3.5 was proven optimal for the LSPR sensing. To reduce the steric hindrance effect as well as to immobilize a large amount of ligand on the nanoparticle surface, various mixtures containing different molar ratios of HS(CH(2))(11)(OCH(2)CH(2))(6)OCH(2)COOH and HS(CH(2))(11)(OCH(2)CH(2))(3)OH were applied to form different self-assembled monolayer surfaces. The results showed that the best molar ratio for antibody conjugation was 1 : 10. When using individual Au nanorod sensors for the detection of prostate specific antigen (PSA), the lowest concentration recorded was ~1 aM (~6 × 10(5) molecules), corresponding to LSPR λ(max) shifts of ~4.2 nm. These results indicate that sensor miniaturization down to the nanoscale level, the reduction of steric hindrance, and optimization of size, shape, and aspect ratio of nanorods have led to a significant improvement in the detection limit of sensors.     

Higher-order tangent epiderivatives and applications to duality in set-valued optimization

In the paper, we introduce higher-order tangent epiderivatives for set-valued maps. Then, we study some basic properties of these concepts. Finally, we establish some results on duality in set-valued optimization. Several examples are given to illustrate the obtained results.

     

Self‐Assembled Gels for Biomedical Applications

Natural and synthetic gel‐like materials have featured heavily in the development of biomaterials for wound healing and other tissue‐engineering purposes. More recently, molecular gels have been designed and tailored for the same purpose. When mixed with, or conjugated to therapeutic drugs or bioactive molecules, these materials hold great promise for treating/curing life‐threatening and degenerative diseases, such as cancer, osteoarthritis, and neural injuries. This focus review explores the latest advances in this field and concentrates on self‐assembled gels formed under aqueous conditions (i.e., self‐assembled hydrogels), and critically compares their performance within different biomedical applications, including three‐dimensional cell‐culture studies, drug delivery, and tissue engineering. Although stability and toxicity issues still need to be addressed in more detail, it is clear from the work reviewed here that self‐assembled gels have a bright future as novel biomaterials.     

Electronic structures and thermochemical properties of the small silicon-doped boron clusters B(n)Si (n=1-7) and their anions

We perform a systematic investigation on small silicon-doped boron clusters B(n)Si (n=1-7) in both neutral and anionic states using density functional (DFT) and coupled-cluster (CCSD(T)) theories. The global minima of these B(n)Si(0/-) clusters are characterized together with their growth mechanisms. The planar structures are dominant for small B(n)Si clusters with n≤5. The B(6)Si molecule represents a geometrical transition with a quasi-planar geometry, and the first 3D global minimum is found for the B(7)Si cluster. The small neutral B(n)Si clusters can be formed by substituting the single boron atom of B(n+1) by silicon. The Si atom prefers the external position of the skeleton and tends to form bonds with its two neighboring B atoms. The larger B(7)Si cluster is constructed by doping Si-atoms on the symmetry axis of the B(n) host, which leads to the bonding of the silicon to the ring boron atoms through a number of hyper-coordination. Calculations of the thermochemical properties of B(n)Si(0/-) clusters, such as binding energies (BE), heats of formation at 0 K (ΔH(f)(0)) and 298 K (ΔH(f)([298])), adiabatic (ADE) and vertical (VDE) detachment energies, and dissociation energies (D(e)), are performed using the high accuracy G4 and complete basis-set extrapolation (CCSD(T)/CBS) approaches. The differences of heats of formation (at 0 K) between the G4 and CBS approaches for the B(n)Si clusters vary in the range of 0.0-4.6 kcal mol(-1). The largest difference between two approaches for ADE values is 0.15 eV. Our theoretical predictions also indicate that the species B(2)Si, B(4)Si, B(3)Si(-) and B(7)Si(-) are systems with enhanced stability, exhibiting each a double (σ and π) aromaticity. B(5)Si(-) and B(6)Si are doubly antiaromatic (σ and π) with lower stability.