2-D PAGE analysis of pesticide-induced stress proteins of E. coli

Logarithmically growing batch cultures of Escherichia coli were exposed to sublethal concentrations of pyrethroid and carbamate pesticides of four different technical grades. This induced 17–20 stress proteins, as observed using two-dimensional polyacrylamide gel electrophoresis. An E. coli culture growing exponentially in Luria Bertani medium (cell density ~2.3×10⁹ cells/ml) was exposed to predetermined sublethal doses of individual pesticides. The cells were harvested after 30 minutes of induction and the stress response was developed in fresh LB medium for three hours under the same growth conditions. Cell pellets were obtained and stored in sonication buffer. Two-dimensional polyacrylamide gel electrophoresis was performed to resolve the proteins. Visualization of the protein spots by rapid silver staining showed 17–20 stress proteins which were absent in the standard protein profile of E. coli. On average 29% of these stress proteins were unique to the pollutant, while the remaining stress proteins overlapped with those of other pesticides. The iso-electric points (PIs) and molecular weights of the proteins were determined by comparing with protein markers with known PIs and molecular weights. Furthermore, upon comparing the pesticide-induced proteins within the same class and between the two different classes (pyrethroid and carbamate), it was apparent that the general nature of the stress remained the same throughout, which indirectly proved that the gene or set of genes responsible for stress expression are also the same, irrespective of the chemical nature of the substituents of the pesticides.     

3‐Germyl‐3,3‐di­methyl­propionic acid derivatives

The crystal structures of 3,3‐di­methyl‐3‐(tri­chloro­germyl)­propionic acid, [Ge(C₅H₉O₂)Cl₃], 3,3‐di­methyl‐3‐(tri­phenyl­germyl)­propionic acid, [Ge(C₆H₅)₃(C₅H₉O₂)], and 3,3‐di­methyl‐3‐(tri‐p‐toly­lgermyl)­propionic acid, [Ge(C₇H₇)₃(C₅H₉O₂)], have slightly distorted tetrahedral geometries about the Ge atoms. All the structures form dimers via strong O—H·O hydrogen bonds, resulting in eight‐membered rings that can be best described in terms of graph‐set notation (8).     

Induced magnetic field stagnation point flow of nanofluid past convectively heated stretching sheet with Buoyancy effects

This paper presents the buoyancy effects on the magneto-hydrodynamics stagnation point flow of an incompressible,viscous,and electrically conducting nanofluid over a vertically stretching sheet.The impacts of an induced magnetic field and viscous dissipation are taken into account.Both assisting and opposing flows are considered.The overseeing nonlinear partial differential equations with the associated boundary conditions are reduced to an arrangement of coupled nonlinear ordinary differential equations utilizing similarity transformations and are then illuminated analytically by using the optimal homotopy investigation strategy(OHAM).Graphs are introduced and examined for different parameters of the velocity,temperature,and concentration profile.Additionally,numerical estimations of the skin friction,local Nusselt number,and local Sherwood number are explored using numerical values.     

To Sandwich Technetium: Highly Functionalized Bis‐Arene Complexes [99mTc(η6‐arene)2]+ Directly from Water and [99mTcO4]−

The labeling of (bio)molecules with metallic radionuclides such as ^99mTc demands conjugated, multidentate chelators. However, this is not always necessary since phenyl rings can directly serve as integrated, organometallic ligands. Bis‐arene sandwich complexes are generally prepared by the Fischer–Hafner reaction. In extension of this, we show that [^99mTc(η⁶‐C₆R₆)₂]⁺‐type complexes are directly accessible from water and [^99mTcO₄]^?, even using arenes incompatible with Fischer–Hafner conditions. To unambiguously confirm the nature of these unprecedented ^99mTc complexes, their rhenium homologous have been prepared by substituting naphthalene ligands in [Re(η⁶‐C₁₀H₈)₂]⁺ with the corresponding phenyl groups. The ease with which highly stable [^99mTc(η⁶‐C₆R₆)₂]⁺ complexes are formed under standard labeling conditions enables a multitude of new potential imaging agents based on commercial pharmaceuticals or lead structures.     

Flow of a Jeffery-Six Constant Fluid Between Coaxial Cylinders withHeat Transfer Analysis

In the present investigation we have discussed the flow of a Jeffrey-six constant incompressible fluid between two infinite coaxial cylinders in the presence of heat transfer analysis. The governing equations of Jeffrey-six constant fluid along with energy equation have been derived in cylindrical coordinates. The highly nonlinear equations are simplified with the help of non-dimensional parameters and then solved analytically with the help of homotopy analysis method (HAM) for two fundamental flows namely Couette and Generalized Couette flow. The effects of emerging parameters are discussed through graphs. The convergence of the HAM solution has been discussed by plotting h-curves.     

Homo‐ and Heterovalent Polynuclear Cerium and Cerium/Manganese Aggregates

Reactions of Ce^III(NO₃)₃?6 H₂O or (NH₄)₂[Ce^IV(NO₃)₆] with Mn‐containing starting materials result in seven novel polynuclear Ce or Ce/Mn complexes with pivalato (^tBuCO ) and, in most cases, auxiliary N,O‐ or N,O,O‐donor ligands. With nuclearities ranging from 6–14, the compounds present aesthetically pleasing structures. Complexes [Ce^IV₆(μ₃‐O)₄(μ₃‐OH)₄(μ‐O₂C^tBu)₁₂] ( 1 ), [Ce^IV₆Mn^III₄(μ₄‐O)₄(μ₃‐O)₄(O₂C^tBu)₁₂(ea)₄(OAc)₄]?4 H₂O?4 MeCN (ea^?=2‐aminoethanolato; 2 ), [Ce^IV₆Mn^III₈(μ₄‐O)₄(μ₃‐O)₈(pye)₄(O₂C^tBu)₁₈]₂[Ce^IV₆(μ₃‐O)₄(μ₃‐OH)₄(O₂C^tBu)₁₀(NO₃)₄] [Ce^III(NO₃)₅(H₂O)]?21 MeCN (pye^?=pyridine‐2‐ethanolato; 3 ), and [Ce^IV₆Ce^III₂Mn^III₂(μ₄‐O)₄(μ₃‐O)₄(^tbdea)₂(O₂C^tBu)₁₂(NO₃)₂(OAc)₂]?4 CH₂Cl₂ (^tbdea^2?=2,2′‐(tert‐butylimino]bis[ethanolato]; 4 ) all contain structures based on an octahedral {Ce^IV₆(μ₃‐O)₈} core, in which many of the O‐atoms are either protonated to give (μ₃‐OH)^? hydroxo ligands or coordinate to further metal centers (Mn^III or Ce^III) to give interstitial (μ₄‐O)^2? oxo bridges. The decanuclear complex [Ce^IV₈Ce^IIIMn^III(μ₄‐O)₃(μ₃‐O)₃(μ₃‐OH)₂(μ‐OH)(bdea)₄(O₂C^tBu)_9.5(NO₃)_3.5(OAc)₂]?1.5 MeCN (bdea^2?=2,2′‐(butylimino]bis[ethanolato]; 5 ) contains a rather compact Ce^IV₇ core with the Ce^III and Mn^III centers well‐separated from each other on the periphery. The aggregate in [Ce^IV₄Mn^IV₂(μ₃‐O)₄(bdea)₂(O₂C^tBu)₁₀(NO₃)₂]?4 MeCN ( 6 ) is based on a quasi‐planar {Mn^IV₂Ce^IV₄(μ₃‐O)₄} core made up of four edge‐sharing {Mn^IVCe^IV₂(μ₃‐O)} or {Ce^IV₃(μ₃‐O)} triangles. The structure of [Ce^IV₃Mn^IV₄Mn^III(μ₄‐O)₂(μ₃‐O)₇(O₂C^tBu)₁₂(NO₃)(furan)]?6 H₂O ( 7 ?6 H₂O) can be considered as {Mn^IV₂Ce^IV₂O₄} and distorted {Mn^IV₂Mn^IIICe^IVO₄} cubane units linked through a central (μ₄‐O) bridge. The Ce₆Mn₈ equals the highest nuclearity yet reported for a heterometallic Ce/Mn aggregate. In contrast to most of the previously reported heterometallic Ce/Mn systems, which contain only Ce^IV and either Mn^IV or Mn^III, some of the aggregates presented here show mixed valency, either Mn^IV/Mn^III (see 7 ) or Ce^IV/Ce^III (see 4 and 5 ). Interestingly, some of the compounds, including the heterovalent Ce^IV/Ce^III 4 , could be obtained from either Ce^III(NO₃)₃?6 H₂O or (NH₄)₂[Ce^IV(NO₃)₆] as starting material.     

Stability‐indicating ultra‐performance liquid chromatography method for the estimation of thymoquinone and its application in biopharmaceutical studies

Thymoquinone (THQ) is known for its neuroprotective and anti‐convulsant properties in preclinical studies. We herewith describe a simple, rapid, selective, sensitive and stability‐indicating UPLC method for the estimation of THQ and its application to biopharmaceutical studies such as in vitro release from nanoparticulate system and in vivo pharmacokinetic study. The method employed gradient elution using a Waters Acquity HSS‐T3 C₁₈ (100 × 2.1 mm, 1.8 µm) UPLC column. The mobile phase consisted of water and acetonitrile, pumped at a flow rate of 0.5 mL/min. The injection volume was 5 µL and THQ was monitored at 294 nm wavelength with a total run time of 6 min. In solution as well as in plasma, the method was found to be linear (r ≥ 0.998), precise (CV ≤ 2.45%) and accurate (recovery ≥ 84.8%) in the selected concentration range of 0.1–0.8 µg/mL. Forced degradation studies revealed that THQ undergoes degradation under acidic, basic, oxidation and UV light stress conditions. However, the developed UPLC method could effectively resolve degradation product peaks from THQ. Further, no interference was found at the retention time of THQ from any plasma components, indicating selectivity of the developed method. For solutions, the limits of detection and quantitation of the method were found to be 0.001 and 0.0033 µg/mL, respectively; while in plasma they were 0.006 and 0.02 µg/mL, respectively. The validated method was successfully applied to quantify THQ in dissolution medium as well as oral in vivo pharmacokinetic study of THQ suspension and THQ‐ solid lipid nanoparticle (THQ‐SLN) formulation. A 2‐fold increase in the relative bioavailability was observed with the THQ‐SLN compared with THQ. The results indicate that the SLN significantly increased plasma concentrations and retention within the systemic circulation. Copyright © 2010 John Wiley & Sons, Ltd.     

A Kinetic Study on Catechol‐Based Belousov–Zhabotinsky Reaction

The present investigation pertains to the kinetic study on bromate‐driven and manganese ion catalyzed Belousov–Zhabotinsky oscillatory chemical reaction having catechol (1,2‐dihydroxybenzene) as the organic substrate in aqueous acid media at 30 ± 0.1^oC under stirred conditions. Although some polyphenols as chemical oscillators are known in the literature but the role of catechol has been marginalized. The reaction system with catechol shows long‐time series of periodic as well as aperiodic oscillations, which were monitored potentiometrically in the oxidation reduction potential (ORP) mode under batch conditions. The various oscillatory parameters such as induction time (t_in), time period (t_p), amplitude (A), and number of oscillations (N) were obtained by drawing a plot between redox potential (mV) versus time (s). It is found that the oscillatory parameters of the system vary with the concentration of the reacting species. The reaction system was also studied in different aqueous acid media, but the detailed studies with respect to experimental parameters have been made in aqueous sulfuric acid medium as it showed a broad oscillatory window and better oscillatory characteristics. Moreover, the oscillatory parameters in general and induction time in particular vary significantly with temperature (15 to 45 ± 0.1^oC). The activation parameters of the system have also been calculated. The oscillatory behavior of the reaction system was also confirmed spectrophotometrically. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 45: 141–151, 2013