Analytical solution for quenching of hot rolled aluminium plates without passing through C-curve

Journal of Thermal Analysis and Calorimetry - At the end of the hot rolling process, quenching is deployed for obtaining the desired microstructure and mechanical properties. During the quenching...     

A Highly Sensitive and Selective Enzymatic Biosensor Based on Direct Electrochemistry of Hemoglobin at Zinc Oxide Nanoparticles Modified Activated Screen Printed Carbon Electrode

A sensitive enzymatic biosensor has been developed for the detection of hydrogen peroxide (H₂O₂), nitrite ( ) and trichloroacetic acid (TCA) by using hemoglobin (Hb) immobilized on activated screen printed carbon electrode (ASPCE) and zinc oxide (ZnO) composite. A pair of well defined redox peaks is observed with a heterogeneous electron transfer rate constant (K_s) of 5.27 s^?1 for Hb at ASPCE/ZnO. The biosensor exhibits the detection of H₂O₂, TCA and in the concentration range of 0.5–129.5 µmol L^?1, 2.5–72.5 mmol L^?1 and 0.2–674 µmol L^?1 with the detection limit of 0.083 µmol L^?1, 0.12 mmol L^?1 and 0.069 µmol L^?1, respectively.     

A new class of laser dyes from acridinedione derivatives

Synthesis of 10-aryl-3,4,6,7,9,10-hexahydro-1,8(2H,5H)-acridinedione as a new class of laser dyes is reported. These dyes lase around 475–495 nm and are compared to the standard dye coumarin 102.     

<Emphasis Type="Italic">Prosopis juliflora</Emphasis>—A green corrosion inhibitor for reinforced steel in concrete

The corrosion of reinforced steel in concrete in 3.5 % NaCl without and with Prosopis juliflora extract at different time intervals has been studied using various techniques including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization study (PDS) and atomic force microscopy (AFM). The results obtained by electrochemical measurements (EIS and PDS) showed that the extract inhibited corrosion by forming a protective layer on the surface of the embedded steel and by altering the reactions of the cathodic and anodic sites of the steel. Further, the AFM images supported the formation of the protective layer over the surface of the embedded steel by inhibitor molecules. The adsorption of the inhibitor molecules over the surface of the embedded steel obeyed the Temkin isotherm. Density functional theory (DFT) calculations for major ingredients of the extract have been carried out. From the results of the DFT calculations, the influence of major ingredients on the anti–corrosion potential of the plant extract has been correlated. The mechanism of inhibitive action of the P. juliflora extract has also been proposed.     

Simple colorimetric detection of dopamine using modified silver nanoparticles

Dopamine(DA) plays an important role in health and peripheral nervous systems. Colorimetric detection of DA has the advantage of color change and simplicity in operation and instrumentation. Herein, we report a highly sensitive and selective colorimetric detection of DA by using two specific ligands modified Ag nanoparticles, where the DA molecules can make dual recognition with high specificity. The colloidal suspension of modified Ag nanoparticles was agglomerated after interacting with DA, while the color of Ag nanoparticles suspension changed from yellow to brown, arising from the interparticle plasmon coupling during the aggregation of Ag nanoparticles. The modified Ag nanoparticles suspension and agglomeration were confirmed by transmission electron microscope images. The optical properties behind the color change were thoroughly investigated by using UV-Vis and Raman techniques. The changes in p H, zeta potential, particle size and surface charge density by adding DA were also determined by using dynamic light scattering measurements. The detection limits of modified Ag probes for DA was calculated to be 6.13′10~(-6) mol L~(-1)(S/N=2.04) and the correlation co-efficient was determined to be 0.9878. Because of the simplicity in operation and instrumentation of the colorimetric method, this work may afford a feasible, fast approach for detecting and monitoring the DA levels in physiological and pathological systems.     

Charge-transfer interaction of aromatic thiols with 2,3-dichloro-5,6-dicyano-p-benzoquinone: spectral and quantum mechanical studies

Charge-transfer (CT) complexes formed between aromatic thiol donors (thiophenol (TP), benzene-1,4-dithiol (BDT), p-aminothiophenol (ATP), p-hydroxythiophenol (HTP), and p-toluenethiol (TTP)) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as an acceptor were studied spectrophotometrically in dichloromethane. Addition of aromatic thiols in dichloromethane to DDQ leads to the formation of colored solutions that exhibit a very broad absorption band in the range 440-800 nm and a band in the region 300-400 nm. On the basis of the energies of LUMO and HOMO from quantum mechanical calculations, the broad band observed in the visible region was assigned to the pi*(a2) <-- pi(b1) transition and a band observed between 300 and 400 nm was assigned to the pi*(a2) <-- pi(a2) transition. The solid CT complexes of aromatic thiols and DDQ were prepared and characterized by FT-IR spectroscopy. The stoichiometry of the CT complexes was determined by Job's continuous variation method. The association constant (KCT), molar extinction coefficient (epsilon), oscillator strength (f), and transition dipole moment (micro) values were calculated from the electronic spectra. The vertical ionization potentials (ID) of the donors were calculated from their corresponding lambdaCT. Quantum mechanical (QM) calculations were performed to determine the ionization potential and the energies of the highest occupied molecular orbital (HOMO) of donors and lowest unoccupied molecular orbital (LUMO) of an acceptor.     

β-Sitosterol Circumvents Obesity Induced Inflammation and Insulin Resistance by down-Regulating IKKβ/NF-κB and JNK Signaling Pathway in Adipocytes of Type 2 Diabetic Rats

β-sitosterol (SIT), the most abundant bioactive component of vegetable oil and other plants, is a highly potent antidiabetic drug. Our previous studies show that SIT controls hyperglycemia and insulin resistance by activating insulin receptor and glucose transporter 4 (GLUT-4) in the adipocytes of obesity induced type 2 diabetic rats. The current research was undertaken to investigate if SIT could also exert its antidiabetic effects by circumventing adipocyte induced inflammation, a key driving factor for insulin resistance in obese individuals. Effective dose of SIT (20 mg/kg b.wt) was administered orally for 30 days to high fat diet and sucrose induced type-2 diabetic rats. Metformin, the conventionally used antidiabetic drug was used as a positive control. Interestingly, SIT treatment restores the elevated serum levels of proinflammatory cytokines including leptin, resistin, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) to normalcy and increases anti-inflammatory adipocytokines including adiponectin in type 2 diabetic rats. Furthermore, SIT decreases sterol regulatory element binding protein-1c (SREBP-1c) and enhances Peroxisome Proliferator–activated receptor-γ (PPAR-γ) gene expression in adipocytes of diabetic rats. The gene and protein expression of c-Jun-N-terminal kinase-1 (JNK1), inhibitor of nuclear factor kappa-B kinase subunit beta (IKKβ) and nuclear factor kappa B (NF-κB) were also significantly attenuated in SIT treated groups. More importantly, SIT acts very effectively as metformin to circumvent inflammation and insulin resistance in diabetic rats. Our results clearly show that SIT inhibits obesity induced insulin resistance by ameliorating the inflammatory events in the adipose tissue through the downregulation of IKKβ/NF-κB and c-Jun-N-terminal kinase (JNK) signaling pathway.     

Fabrication of Nickel Tetrasulfonated Phthalocyanine Functionalized Multiwalled Carbon Nanotubes on Activated Glassy Carbon Electrode for the Detection of Dopamine

The nickel tetrasulfonated phthalocyanine (NiTsPc) functionalized multiwalled carbon nanotube (MWCNT) nanocomposite was prepared by a simple sonochemical method. Here, NiTsPc served as a dispersing agent for MWCNT via π? π interaction between MWCNT and NiTsPc. The activated glassy carbon electrode (AGCE) modified with MWCNT‐NiTsPc composite exhibited a good electrocatalytic ability toward dopamine and displayed a good linear dependence in the concentration range of 20 nM–1.384 mM with a sensitivity of 0.17 µA µM^?1 cm^?2. The detection limit is 1 nM based on the signal‐to‐noise ratio of 3.     

Antioxidant and antibacterial activities of bark extracts from Commiphora berryi and Commiphora caudata

This study investigates the in vitro antioxidant and antimicrobial activities of eight extracts obtained from the dried barks of Commiphora berryi and Commiphora caudata (Burseraceae). The radical scavenging activity was assessed by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and nitric oxide assays. The methanolic extracts of C. berryi and C. caudata showed significant DPPH radical scavenging activity, with IC?? values of 26.92 and 21.16?μg?mL?1, respectively, and low radical scavenging activity against the nitric oxide assay. The antimicrobial activity of the plants was tested against the Gram-positive and Gram-negative bacteria. The ethyl acetate, chloroform and petroleum ether extracts of C. berryi showed good antibacterial activity against Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of 0.26?mg?mL?1, whereas the ethyl acetate and methanol extracts of C. caudata showed moderate antimicrobial activity with an MIC of more than 2.0?mg?mL?1 against P. aeruginosa compared to the petroleum ether and chloroform extracts, which showed an MIC of 1.1?mg?mL?1. The methanolic extracts of C. berryi and C. caudata also showed moderate cytotoxic activity against a human mammary carcinoma cell line (MCF-7), with values IC?? of 82.6 and 88.4?μg?mL?1, respectively.     

Furan-decorated neutral Re(I)-based 2D rectangle and 3D trigonal prism

Neutral, stable and luminescent metallacycles decorated with furan units, a 2D rectangle with four furans and a 3D trigonal prism with six furans, were synthesized from readily accessible starting materials through a fac-Re(CO)(3)-directed approach.