Kinetic spectrophotometric determination of the macrolide antibiotic josamycin in formulations

A simple kinetic spectrophotometric method was developed for the determination of josamycin in its dosage forms. The method is based on oxidation of the drug with alkaline potassium permanganate at room temperature for a fixed time of 20 min and measuring the produced green color at 611 nm. The absorbance-concentration plot is rectilinear over the range of 2-10 microg/mL (2.4 x 10(6)-1.2 x 10(-5)M) with minimum detectability of 1.0 microg/mL (1.2 x 10(-6)M). The determination of josamycin by fixed concentration and the rate-constant methods is also feasible with the calibration equations obtained, but the fixed-time method proved to be more applicable. The procedure was applied successfully to commercial tablets, and statistical analysis showed that the results compared favorably with those obtained by reference methods. The effect of sensitizers and surfactants on the performance of the proposed method was also studied. A proposal of the reaction pathway was presented.     

Kinetics and Mechanism of the Autocatalytic Oxidation of L-Asparagine in a Moderately Concentrated Sulfuric Acid Medium

The reaction kinetics of the Autocatalytic Oxidation of L-asparagine by permanganate ions has been investigated in moderately strong acid medium using the spectrophotometric technique. In all cases studied, an autocatalytic effect due to Mn²⁺ ions formed as a reaction product was observed. Both catalytic and noncatalytic processes were determined to be first order with respect to the permanganate ions while a first and a fractional order with respect to the amino acid for noncatalytic and catalytic reactions were obtained, respectively. The overall rate equation for this process may be written asd[MO₄ ^–]/dt= k´₁[MnO₄ ^–]+k´₂[MnO₄ ^–][Mn⁺²],where k´₁ and k´₂ are rate pseudoconstants for noncatalytic and catalytic reactions, respectively. The influence of some factors such as temperature and reactant concentration on the rate constants has been studied, and the activation parameters have been calculated. Reaction mechanisms satisfying observations for both catalytic and noncatalytic routes have been presented.     

ZrCl4 as an Efficient Catalyst for Crossed‐Aldol Condensation of Cyclic Ketones with Aromatic Aldehydes in Refluxing Ethanol

The aldol condensation reaction of cyclic ketones with aromatic aldehydes in ethanol under reflux conditions using ZrCl₄ as a catalyst to afford the corresponding α,α′‐bis(substituted benzylidene and cinnamylidene)cycloalkanones in excellent yields has been described. No self‐condensation product was produced.     

Investigation of sol-gel matrices containing crude metallothionein from <Emphasis Type="Italic">Scchizosaccharomyces pombe</Emphasis> for water treatment applications

The application of silica sol–gel particles containing crude metallothionein (MT) was investigated for cadmium removal from water. The metallothionein was first extracted from the yeast Scchizosaccharomyces pombe, and entrapped in the sol–gel matrices. Then sol–gel particles with the different sizes (ranging from 45 to 225 μm) were made. The effect of different flow rates as well as different particle sizes on adsorption of cadmium was investigated. The particle size has a greater effect on Cd adsorption than flow rate in the system studied. The breakthrough curves in the column were modeled using an empirical two parameter fixed-bed adsorption model. The model relates the changes of cadmium concentration in effluent to the standard deviation (σ) and characteristic of time (t ₀).     

Uniqueness for an overdetermined boundary value problem for the p-Laplacian

For set , and let be a measure with compact support. Suppose, for , there are functions and (bounded) domains , both containing the support of with the property that in (weakly) and in the complement of . If in addition is convex, then and .

     

A joint optimisation model for inventory replenishment,product assortment,shelf space and display area allocation decisions

In this paper, we propose an optimisation model to determine the product assortment, inventory replenishment, display area and shelf space allocation decisions that jointly maximize the retailer’s profit under shelf space and backroom storage constraints. The variety of products to be displayed in the retail store, their display locations within the store, their ordering quantities, and the allocated shelf space in each display area are considered as decision variables to be determined by the proposed integrated model. In the model formulation, we include the inventory investment costs, which are proportional to the average inventory, and storage and display costs as components of the inventory costs and make a clear distinction between showroom and backroom inventories. We also consider the effect of the display area location on the item demand. The developed model is a mixed integer non-linear program that we solved using LINGO software. Numerical examples are used to illustrate the developed model.     

Effect of annealing treatment on the magnetic properties of mechanochemical synthesized La0.8Pb0.2MnO3 manganites

In this paper, we have investigated the effect of annealing on structural and magnetic properties of La_0.8Pb_0.2MnO₃ (LPMO) polycrystalline samples. Mechanochemical procedure has been used to produce LPMO nanocrystalline samples from oxide precursors. From the AC susceptibility measurements we found that the magnitude of susceptibility increases and the paramagnetic–ferromagnetic (PM–FM) transition width decreases by annealing the ball milled powders. Also, reentrant spin glass (RSG) behavior has been found in high temperature annealed samples. It seems that, due to the evaporation of PbO in high temperature annealed samples, vacancies created in perovskite structure and portion of the Mn³⁺–O–Mn⁴⁺ network is broken. So the FM double-exchange interaction is weakened due to the magnetic dilution and the antiferromagnetc (AFM) phase fraction increases in high temperature annealed samples. The competition between FM double-exchange interaction and AFM super-exchange interaction produces spin frustration and is responsible for the occurrence of RSG.     

A Novel Approach to Unraveling the Apoptotic Potential of Rutin (Bioflavonoid) via Targeting Jab1 in Cervical Cancer Cells

Rutin has been well recognized for possessing numerous pharmacological and biological activities in several human cancer cells. This research has addressed the inhibitory potential of rutin against the Jab1 oncogene in SiHa cancer cells, which is known to inactivate various tumor suppressor proteins including p53 and p27. Further, the inhibitory efficacy of rutin via Jab1 expression modulation in cervical cancer has not been yet elucidated. Hence, we hypothesized that rutin could exhibit strong inhibitory efficacy against Jab1 and, thereby, induce significant growth arrest in SiHa cancer cells in a dose-dependent manner. In our study, the cytotoxic efficacy of rutin on the proliferation of a cervical cancer cell line (SiHa) was exhibited using MTT and LDH assays. The correlation between rutin and Jab1 mRNA expression was assessed by RT-PCR analysis and the associated events (a mechanism) with this downregulation were then explored via performing ROS assay, DAPI analysis, and expression analysis of apoptosis-associated signaling molecules such as Bax, Bcl-2, and Caspase-3 and -9 using qRT-PCR analysis. Results exhibit that rutin produces anticancer effects via inducing modulation in the expression of oncogenes as well as tumor suppressor genes. Further apoptosis induction, caspase activation, and ROS generation in rutin-treated SiHa cancer cells explain the cascade of events associated with Jab1 downregulation in SiHa cancer cells. Additionally, apoptosis induction was further confirmed by the FITC-Annexin V/PI double staining method. Altogether, our research supports the feasibility of developing rutin as one of the potent drug candidates in cervical cancer management via targeting one such crucial oncogene associated with cervical cancer progression.     

1-(对甲苯基)-2-(三对甲苯基-5-亚磷酰基)乙醛的汞(Ⅱ)配合物的X射线晶体学、光谱表征和理论计算研究

通过2-溴-1-（对甲苯基）乙醛与三（对甲苯基）膦的反应制备α-磷配体：1-（对甲苯基）-2-（三对甲苯基-5-亚磷酰基）乙醛（L）。氯化镉和溴化汞与L分别反应,生成配合物[Cd（L）Cl₂]₂（C1）和[Hg（L）（μ₂-Br）Br]₂（C2）。用IR和NMR（¹H,¹³C,³¹P）对配合物进行了表征。通过单晶X射线衍射测定了C2的结构,并在B3LYP/6-31G^*水平对C2的结构进行了DFT计算研究,以揭示C2的复合反应位点与Schiff碱等亲核基团的相互作用。