Silica sulfuric acid: an efficient reusable heterogeneous solid support for the synthesis of 3H,3′H-spiro[benzofuran-2,1′isobenzofuran]-3,3′-diones under solvent-free condition

A highly efficient protocol for the library synthesis of biologically important 3H,3′H-spiro[benzofuran-2,1′isobenzofuran]-3,3′-diones has been developed by employing silica sulfuric acid (SSA) as solid acid support under solvent-free condition. The dual characteristics of SSA, as an activating agent as well as oxidizing agent, have been well exposed in these syntheses. The intrinsic advantages of the methodology are the use of solvent-free reaction condition without using any toxic reagents or metal catalyst, operational simplicity, recyclability of the solid support, good availability of the starting materials, and excellent yields which make the method attractive, economic, and ‘benign by design’.     

Synthesis,characterization and significant antimicrobial properties of CZTS nanoparticles against pathogenic strains

Antibacterial properties have wide application in water disinfection, textile industry, medicine, and food packaging. The present work focuses on the efficacy of Cu₂ZnSnS₄ (CZTS) nanoparticles as a possible promising antibacterial agent along those directions. CZTS nanomaterials were synthesized following the solvo-thermal method using Teflon-lined stainless-steel autoclave. Nanoparticles were characterized using XRD, Raman spectroscopy, UV–visible spectroscopy, and SEM techniques. SEM shows that the size of synthesized nanoparticle was 50-100 ?nm. Antibacterial activity of CZTS nanoparticles was performed against ten pathogenic bacterial strains, which include 5 Gram-positive strains (viz. Staphylococcus epidermidis, Bacillus megaterium, Mycobacterium smegmatis, Lactobacillus and Staphylococcus aureus) and 5 Gram-negative strains (viz. Serratia marcescense, Salmonella typhi, Escherichia coli, Proteus vulgaris and Pseudomonas aeruginosa), using the well diffusion method. CZTS nanoparticles shows significant antibacterial activity against both the Gram-positive and Gram-negative bacterial strains. Notable increase in the antibacterial activity of CZTS nanoparticles has been observed with the increase in the concentration of nanoparticles in terms of zone of inhibition (ZOI), which helps us to study the cell toxicity. Minimum inhibitory concentration (MIC) has been observed with the lowest concentration of nanoparticles that show visible growth of bacteria, which certainly may contribute significantly toward possible medicinal applications of CZTS nanoparticles.     

Oxidation of propane to acrylic acid and acetic acid over alkaline earth-doped Mo-V-Sb-Ox catalysts

Alkaline earth metal (Mg, Ca, Sr and Ba)-doped Mo-V-Sb-Ox catalysts, prepared by a dry-up method, have been investigated for their catalytic performance in the oxidation of propane under different reaction conditions. The catalysts have been characterized by N2 adsorption-desorption, temperature-programmed desorption (TPD) of NH3, SEM and XRD. Influence of water vapor on the catalytic performance, particularly on the selectivities to acetic acid and acrylic acid, has also been studied. The selectivity to acrylic acid was improved significantly by the doping of alkaline earth metals to Mo-V-Sb-Ox catalysts. The surface acidic sites of the catalyst decreased with the doping of the catalyst with alkaline earth metals, which ultimately was found to be beneficial for obtaining high selectivity to acrylic acid. The catalytic activity and product selectivities were found to be influenced by the reaction temperature, C3H8/O2 ratio and space velocity. A significant improvement in the selectivity to acrylic acid has also been observed by the addition of water vapor in the feed of propane and oxygen in the oxidation of propane.     

Optimal replenishment time for retailer under partial upstream prepayment and partial downstream overdue payment for quadratic demand

In competitive edge, the proffer of delay payment is of great consequence tool to boost the market demand by exerting influence of more customers. In opposition to, merchandiser may be asked to pay some per cent of purchasing cost before receiving products to reduce the risk of cancellation of order. In this article, optimal replenishment time for merchandiser under partial upstream prepayment and partial downstream overdue payment is presented under quadratic demand with three different models: (1) without deterioration, (2) with constant deterioration and (3) maximum fixed-lifetime deterioration as loss of utility is the real situation of products like fruits, vegetables, juices, etc., and to reduce deterioration of the product, merchandiser spends capital on preservation technology to preserve the item. Quadratic demand is suitable for the products for which demand increases initially and afterward it starts to decrease. The decision policies are analysed for the merchandiser. The objective is to minimize merchandiser’s total cost with respect to decision variables. The models are supported with numerical examples. Sensitivity analysis is carried out to derive insights for decision maker.     

Breast tumor vascularity identified by contrast enhanced ultrasound and pathology: initial results

Quantifiable measures of vascularity obtained from contrast enhanced color flow images were correlated with pathologic vascularity measurements in ten female patients with a solid breast mass. Each patient received Levovist Injection (Berlex Laboratories Inc., Montville, NJ). Color flow images pre- and post-contrast were obtained using an HDI 3000 unit (ATL, Bothell, WA) before removing the mass for pathologic vascularity assessments. Image-processing techniques were used to obtain both the ultrasound and pathologic vascularity measurements. Multiple linear regression found significant correlations for ultrasonic vascularity measurements post contrast and pathology (P = 0.02 and 0.06). No correlations were found between pre-contrast ultrasound and pathology. In conclusion, post-contrast ultrasonic flow measures provide a non-invasive measure of breast tumor neovascularity. However, the patient population is small, and until further patients are analyzed, these conclusions are preliminary.     

多相CeO2催化剂上氧化吲哚与醛的选择性C3烯基化反应

本文报道了将市售CeO2作为一种高活性和可重复使用的催化剂用于无溶剂条件下氧化吲哚与醛的C3选择性烷基化反应.这种催化方法一般适用于不同的芳香族和脂肪族醛,得到3-烷基二烯-辛醇,产率高(87%–99%),立体选择性高(79%–93%为E-异构体).这是从氧化吲哚与各种脂肪族醛催化合成3-烯基氧化吲哚的首例.采用原位红外光谱研究了CeO2上Lewis酸位点与苯甲醛之间的Lewis酸-碱相互作用.不同粒径CeO2催化剂的构效关系研究表明,无缺陷CeO2表面是该反应的活性中心.     

Complex Permittivity Spectra of Binary Pyridine–Amide Mixtures Using Time–Domain Reflectometry

Frequency spectra of the complex permittivity for pyridine–amide binary mixtures have been determined over the frequency range 10 MHz to 10 GHz, at 5, 15, 25, and 40°C, using the time–domain reflectometry method, for 11 compositions of each pyridine–amide system, e.g., formamide, N-methylformamide, and N,N-dimethylformamide. The relaxation in these systems can be described by a single relaxation time using the Debye model. The static dielectric constant, relaxation time, the corresponding excess dielectric properties, Kirkwood correlation factor, and molar activation energy of the mixtures have been determined. The excess permittivity is found to be positive in the amide-rich region and negative in the pyridine-rich region. The excess inverse relaxation time is negative, except in the pyridine-rich region. The static dielectric constants for the mixtures have been fitted with the modified Bruggeman model. The temperature-dependent relaxation times show the expected Arrhenius behavior.     

High resolution 13C-NMR spectroscopy of sodium carboxy methyl cellulose

Results of NMR studies on intact sodium carboxy methyl cellulose (SCMC) are presented. Similar studies in the literature are all on partially depolymerized SCMC. The degree of substitution and the relative distribution of substituents at OH-2, OH-3, and OH-6 of anhydro D -glucose residue in intact SCMC were determined by high resolution ¹³C-NMR spectroscopy (125 MHz). It is observed that the degree of substitution at OH-6 is almost equal to that at OH-3. In two SCMC samples, which are widely different in molecular weight and degree of substitution (ds), the relative reactivity order of the hydroxyl groups was found to be OH-2 > OH-6 ? OH-3. The NMR assignments were based on calculated shifts of carbons of anhydroglucose moiety in an oligosaccharide due to substitution.     

Evaluation of Probiotic Characteristics of Siderophoregenic <Emphasis Type="Italic">Bacillus</Emphasis> spp. Isolated from Dairy Waste

Siderophoregenic Bacillus strain DET9 has been selectively isolated from dairy waste. It was evaluated for probiotic characteristics and susceptibility pattern against antibiotics. Its spores showed excellent tolerance to simulated gastrointestinal tract conditions and exhibited antimicrobial activity against organisms such as Escherichia coli, Micrococcus flavus, and Staphylococcus aureus. Its susceptibility to antibiotics reduces the prospect to donate resistance determinants if administered in the form of probiotic preparations. It was observed to produce ∼60 mg/l catecholate type of siderophore under iron stressed conditions, identified as a 2,3-dihydroxy benzoic acid by high-performance liquid chromatography, infrared spectroscopy, nuclear magnetic resonance, and mass spectral analysis. Partial 16S-rRNA gene sequencing analysis shows that the isolate exhibited homology with Bacillus thuringiensis and Bacillus weihenstephanensis, whereas biochemical characterization revealed its novelty. DET9 exhibited no mortality of fishes in a 60-day trial, when fishes (surfi tetra) were challenged up to 100 ppm cell concentration, with their daily diet.     

Hydrogen uptake capacity of C2H4Sc and its ions: A density functional study

We report the gravimetric hydrogen uptake capacity of C₂H₄Sc complex and isoelectronic ions using Density Functional Theory. We predict that C₂H₄Sc⁺ can bind maximum seven hydrogen molecules in dihydrogen form giving gravimetric uptake capacity of 16.2 wt %, larger by about 2 and 4 wt % than the neutral and anion, respectively. We also found that the interaction of hydrogen molecules with C₂H₄Sc⁺ ion is characteristically different than that with neutral and anion. Vibrational spectroscopic study reveals that C₂H₄Sc and isoelectronic ions are quantum mechanically stable with their characteristic change in respective identified mode. The large gravimetric H₂ uptake capacity of C₂H₄Sc⁺ is well above the target specified by Department of Energy (DOE) by 2015. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010