Fabrication of interdigitated high-performance zinc oxide nanowire modified electrodes for glucose sensing

Diabetes is a metabolic disease with a prolonged elevated level of glucose in the blood leads to long-term complications and increases the chances for cardiovascular diseases. The present study describes the fabrication of a ZnO nanowire (NW)-modified interdigitated electrode (IDE) to monitor the level of blood glucose. A silver IDE was generated by wet etching-assisted conventional lithography, with a gap between adjacent electrodes of 98.80 μm. The ZnO-based thin films and NWs were amended by sol–gel and hydrothermal routes. High-quality crystalline and c-axis orientated ZnO thin films were observed by XRD analyses. The ZnO thin film was annealed for 1, 3 and 5 h, yielding a good-quality crystallite with sizes of 50, 100 and 110 nm, and the band gaps were measured as 3.26, 3.20 and 3.17 eV, respectively. Furthermore, a flower-modeled NW was obtained with the lowest diameter of 21 nm. Our designed ZnO NW-modified IDE was shown to have a detection limit as low as 0.03 mg/dL (correlation coefficient = 0.98952) of glucose with a low response time of 3 s, perform better than commercial glucose meter, suitable to instantly monitor the glucose level of diabetes patients. This study demonstrated the high performance of NW-mediated IDEs for glucose sensing as alternative to current glucose sensors.     

Dynamics of large elongated RNA by NMR carbon relaxation

We present an NMR strategy for characterizing picosecond-to-nanosecond internal motions in uniformly 13C/15N-labeled RNAs that combines measurements of R1, R1rho, and heteronuclear 13C{1H} NOEs for protonated base (C2, C5, C6, and C8) and sugar (C1') carbons with a domain elongation strategy for decoupling internal from overall motions and residual dipolar coupling (RDC) measurements for determining the average RNA global conformation and orientation of the principal axis of the axially symmetric rotational diffusion. TROSY-detected pulse sequences are presented for the accurate measurement of nucleobase carbon R1 and R1rho rates in large RNAs. The relaxation data is analyzed using a model free formalism which takes into account the very high anisotropy of overall rotational diffusion (Dratio approximately 4.7), asymmetry of the nucleobase CSAs and noncollinearity of C-C, C-H dipolar and CSA interactions under the assumption that all interaction tensors for a given carbon experience identical isotropic internal motions. The approach is demonstrated and validated on an elongated HIV-1 TAR RNA (taum approximately 18 ns) both in free form and bound to the ligand argininamide (ARG). Results show that, while ARG binding reduces the amplitude of collective helix motions and local mobility at the binding pocket, it leads to a drastic increase in the local mobility of "spacer" bulge residues linking the two helices which undergo virtually unrestricted internal motions (S2 approximately 0.2) in the ARG bound state. Our results establish the ability to quantitatively study the dynamics of RNAs which are significantly larger and more anisotropic than customarily studied by NMR carbon relaxation.     

Tin-Naphthalene Sulfonic Acid Complexes as Photostabilizers for Poly(vinyl chloride)

Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the application of additives. New organotin complexes containing 4-aminonaphthalene-1-sulfonic acid were synthesized and their role as poly(vinyl chloride) photostabilizers were evaluated. The reaction of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and appropriate di- or trisubstituted tin chloride (triphenyltin chloride, tributyltin chloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol under reflux gave the corresponding tin-naphthalene complexes with yields of 75%–95%. Elemental analyses and spectroscopic techniques including infrared and nuclear magnetic resonance (proton and tin) were used to confirm their structures. The tin complexes were added to poly(vinyl chloride) to produce thin films that irradiated with ultraviolet light. Various parameters were assessed, such as the weight loss, formation of specific functional groups, changes in the surface due to photoirradiation, and rate constant of photodegradation, to test the role played by the organotin complexes to reduce photodegradation in polymeric films. The results proved that organotin complexes acted as photostabilizers in these circumstances. The weight loss, formation of fragments containing specific functional groups, and undesirable changes in the surface of polymeric films were limited in the presence of organotin complexes. Organotin complexes containing three phenyl groups showed the most desirable stabilization effect. These act as efficient primary and secondary photostabilizers, and as decomposers for peroxides. In addition, such an additive inhibits the dehydrochlorination process, which is the main cause of poly(vinyl chloride) photodegradation.     

Theoretical studies on mechanical and electronic properties of s-triazine sheet

Abstract

Mechanical and electronic properties of s-triazine sheet are studied using first-principles calculations based on density functional theory. The in-plane stiffness and bulk modulus for s-triazine sheet are found to be less than that of heptazine. The reduction can be related to the nature of the covalent bonds connecting the adjacent sheets and the number of atoms per unit cell. The Poisson’s ratio of s-triazine sheet is half the value to that of graphene. Additionally, the calculated values of the two critical strains (elastic and yielding points) of s-triazine sheet are in the same order of magnitude to that for heptazine which was calculated using MD simulations in the literature. It is also demonstrated that s-triazine sheet can withstand larger tension in the plastic region. These results established a stable mechanical property for s-triazine sheet. We found a linear relationship of bandgap as a function of bi-axial tensile strain within the harmonic elastic region. The reduced steric repulsion of the lone pairs (p_x-, p_y-) causes the p_z-like orbital to shift to high energy, and consequently an increase in the bandgap. We find no electronic properties modulation of the s-triazine sheet under electric field up to a peak value of 10 V/nm. Such noble properties may be useful in future nanomaterial applications.     

Synthesis of 4-alkyl-, 4-aryl- and 4-arylamino-5-aminoisoquinolin-1-ones and identification of a new PARP-2 selective inhibitor

The considerable interest in substituted isoquinolin-1-ones related to 5-aminoisoquinolin-1-one (5-AIQ) as drugs points to a need for an efficient and straightforward synthesis of the 4,5-disubstituted bicycles. Bromination of 5-nitroisoquinolin-1-one gave 4-bromo-5-nitroisoquinolin-1-one but neither this nor 5-amino-4-bromoisoquinolin-1-one would participate in Pd-catalysed couplings. Protection of the lactam as 1-methoxy- and 1-benzyloxy-4-bromo-5-nitroisoquinolines, however, permitted Stille, Suzuki and Buchwald-Hartwig couplings to take place in high yields, insensitive to electronic demands and severe steric bulk in the arylboronic acids. Lithiation of 4-bromo-1-methoxy-5-nitroisoquinoline and quench with iodomethane gave 1-methoxy-4-methyl-5-nitroisoquinoline in low yield. Demethylation of the 1-methoxy-4-substituted-5-nitroisoquinolines with hydrogen bromide gave 4-substituted-5-nitroisoquinolin-1-ones, whereas hydrogenolytic debenzylation was achieved with simultaneous reduction of the 5-nitro group. 5-Amino-4-(4-trifluoromethylphenyl)isoquinolin-1-one was identified as a new potent and selective inhibitor of poly(ADP-ribose)polymerase-2 (PARP-2).     

Fingerprint chemotaxonomic GC–TOFMS profile of wood and bark of mangrove tree Sonneratia caseolaris (L.) Engl.

The bark and wood of Sonneratia caseolaris (L.) Engl. have been analyzed for chemical profile by GC–TOFMS. Overall thirty-two compounds from bark and twenty-eight compounds from wood have been detected. Sixteen constituents have been found to be common in both the extracts. GC–TOFMS chemical profile may be a significant finger print chemotaxonomic marker as an identity of this plant.     

Lignans and other constituents from aerial parts of Haplophyllum villosum

During our phytochemical investigation of Haplophyllum villosum (Rutaceae), a perennial herb from Iran, a new 4,8-diaryl-3,7-dioxobicyclo-(3,3,0)-octane type lignan, eudesmin A (1), together with four known compounds--eudesmin (2), haplamine (3), umbelliferone (4) and scopoletin (5)--were isolated from aerial parts of the plant. The structures of the compounds were elucidated using NMR spectral analysis (1H-NMR, 13C-NMR, HSQC, COSY and HMBC) as well as UV, IR and MS spectra and comparison with previously reported data.     

Identification of potential complementary serum biomarkers to differentiate prostate cancer from benign prostatic hyperplasia using gel- and lectin-based proteomics analyses

Diagnosis of prostate cancer (PCa) is currently much reliant on the invasive and time-consuming transrectal ultrasound-guided biopsy of the prostate gland, particularly in light of the inefficient use of prostate-specific antigen as its biomarker. In the present study, we have profiled the sera of patients with PCa and benign prostatic hyperplasia (BPH) using the gel- and lectin-based proteomics methods and demonstrated the significant differential expression of apolipoprotein AII, complement C3 beta chain fragment, inter-alpha-trypsin inhibitor heavy chain 4 fragment, transthyretin, alpha-1-antitrypsin, and high molecular weight kininogen (light chain) between the two groups of patients' samples. Our data are suggestive of the potential use of the serum proteins as complementary biomarkers to effectively discriminate PCa from BPH, although this requires further extensive validation on clinically representative populations.     

Cytoprotective Effect of Benzyl <em>N'</em>-(5-Chloro-indol-3-yl-methylidene)-hydrazinecarbodithioate Against Ethanol-Induced Gastric Mucosal Injury in Rats

Indolic compounds have attracted a lot of attention due to their interesting biological properties. The present study was performed to evaluate the subacute toxicity and anti-ulcer activity of BClHC against ethanol-induced gastric ulcers. Experimental animal groups were orally pre-treated with different doses of BClHC (50, 100, 200 and 400 mg/kg) in 10% Tween 20 solution (vehicle). Blank and ulcer control groups were pre-treated with vehicle. The positive group was orally pretreated with 20 mg/kg omeprazole. After one hour, all groups received absolute ethanol (5 mL/kg) to generate gastric mucosal injury except the blank control group which was administered the vehicle solution. After an additional hour, all rats were sacrificed, and the ulcer areas of the gastric walls determined. Grossly, the ulcer control group exhibited severe mucosal injury, whereas pre-treatment with either derivative or omeprazole resulted in significant protection of gastric mucosal injury. Flattening of gastric mucosal folds was also observed in rats pretreated with BClHC. Histological studies of the gastric wall of ulcer control group revealed severe damage of gastric mucosa, along with edema and leucocytes infiltration of the submucosal layer compared to rats pre-treated with either BClHC or omeprazole where there were marked gastric protection along with reduction or absence of edema and leucocytes infiltration of the submucosal layer. Subacute toxicity study with a higher dose of derivative (5 g/kg) did not manifest any toxicological signs in rats. In conclusions, the present finding suggests that benzyl N'-(5-chloroindol-3-ylmethylidene)hydrazinecarbodithioate promotes ulcer protection as ascertained by the comparative decreases in ulcer areas, reduction of edema and leucocytes infiltration of the submucosal layer.