Parameters Influencing Third‐Phase Formation in the Extraction of Th(NO3)4 by some Trialkyl Phosphates

Third‐phase formation in the extraction of Th(IV) by trialkyl phosphates (TalP) such as tri‐n‐butyl phosphate (TBP), tri‐iso‐butyl phosphate (TiBP), tri‐sec‐butyl phosphate (TsBP), tri‐n‐amyl phosphate (TAP), tri‐2‐methylbutyl phosphate (T2MBP), tri‐iso‐amyl phosphate (TiAP), tri‐sec‐amyl phosphate (TsAP), and tri‐cyclo‐amyl phosphate (TcyAP) has been investigated under various conditions. Formation of a third phase in the extraction of Th(IV) by TBP/n‐dodecane as a function of TBP concentration at 303 K was studied. Measurements were also carried out on the extraction of Th(IV) from its solution with near‐zero free acidity by various phosphate/diluent binary solutions (1.1 M) as a function of temperature. Third‐phase formation in the extraction of Th(IV) by 1.1 M TalP in various diluents from nitric acid media has also been studied as a function of equilibrium aqueous‐phase acidity at 303 K. Empirical equations to predict limiting organic concentration with respect to various parameters for third‐phase formation in the extraction of Th(IV) by TBP and TAP from nitric acid media have been derived. Some of the above phosphates have been investigated for the distribution of Th(NO₃)₄ between the “diluent‐rich phase” (DP) and “third‐phase” (TP) in the extraction of Th(IV) by 1.1 M TalP in various diluents from its saturated solution with near‐zero free acidity at 303 K. Results of the above studies are presented in this paper. Based on these studies, the effects of extractant concentration, the temperature, the nature of the diluent, the equilibrium aqueous‐phase acidity, and the structure of the extractant on third‐phase formation behavior of trialkyl phosphates are described in this paper.     

Systematic hardness measurements on some rare earth garnet crystal

Microhardness measurements were undertaken on twelve rare earth garnet crystals. In yttrium aluminium garnet and gadolinium gallium garnet, there was no measurable difference in the hardness values of pure and nominally Nd-doped crystals. The hardness values were correlated with the lattice and elastic constants. An analysis of hardness data in terms of the interatomic binding indicated a high degree of covalency. Dedicated to the memory of Dr R Thyagarajan, eminent Solid State Physicist.     

In vitro and in vivo effects of phenolic antioxidants against cisplatin-induced nephrotoxicity

We have investigated the effect of phenolic antioxidants on cisplatin-induced cytotoxicity in vero (African Green Monkey Kidney) cells and in rat renal cortical slices in vitro, and on cisplatin-induced nephrotoxicity in rats in vivo. Incubation of cisplatin with vero cells resulted in time- and concentration-dependent cytotoxicity, as characterized by decreased tryphan blue exclusion (TBE) and increased release of lactate dehydrogenase (LDH) into the medium. Cisplatin also caused reduction of glutathione (GSH) in a concentration-dependent manner. In the rat renal cortical slices model, incubation of cisplatin for 120 min caused an increase in malondialdehyde (MDA), a decrease in GSH and inhibited p-aminohippurate (PAH) uptake in a concentration-dependent manner. Among phenolic antioxidants, isoeugenol (IG) was found to be more active against cisplatin-induced cytotoxicity in vero cells as well as in rat renal cortical slices than eugenol (EG) and dehydrozingerone (DZ). However none of the test compounds were able to arrest the reduction of the GSH content induced by cisplatin in either the vero cells or the renal cortical slice model. Administration of cisplatin (3 mg/kg) i.p. to rats resulted in significant reduction of body weight, and elevation of blood urea nitrogen (BUN) and serum creatinine. Treatment with IG 10 mg/kg i.p. 1 h before cisplatin resulted in partial but significant protection against the cisplatin-induced reduction of body weight, and elevation of BUN and serum creatinine, the protection being 34, 46, and 62%, respectively. EG and DZ (10 mg/kg, i.p.) were found to be inactive in vivo. Because IG is a potent free radical scavenger and protects against cisplatin-induced toxicitiy, the present results have many clinical implications in chemotherapy and thus warrants further investigation.     

Application of a numerical model for circulation,temperature and pollutant distribution in Hamilton Harbour

The restoration of Hamilton Harbour, from an environmental standpoint, is a current concern for the agencies involved with remediation efforts in the harbour. Estimates of circulation and mixing are needed to assess the fate and transport of water quality constituents in the harbour. A three-dimensional hydrodynamic modeling system (ELCOM) is used to study the circulation and thermal structure in the harbour. The model results were compared with profiles of temperature at several moorings and currents and water levels in the harbour. The model showed considerable skill in reproducing the thermal structure, surface currents and water levels. Mean summer circulation in the harbour showed two counter-rotating gyres occupying the harbour. The model produced harbour-lake exchange characteristics are in agreement with previous studies. Simulations using passive tracers qualitatively agreed with chemical tracer studies conducted near a sewage treatment plant outfall. The accuracy of these simulations suggests that the model is capable of describing flow and transport of material required for detailed water quality simulations.     

Asthma and respiratory symptoms in hospital workers related to dampness and biological contaminants

Abstract The National Institute for Occupational Safety and Health investigated respiratory symptoms and asthma in relation to damp indoor environments in employees of two hospitals. A cluster of six work‐related asthma cases from one hospital department, whose symptoms arose during a time of significant water incursions, led us to conduct a survey of respiratory health in 1171/1834 employees working in the sentinel cases hospital and a nearby hospital without known indoor environmental concerns. We carried out observational assessment of dampness, air, chair, and floor dust sampling for biological contaminants, and investigation of exposure‐response associations for about 500 participants. Many participants with post‐hire onset asthma reported diagnosis dates in a period of water incursions and renovations. Post‐hire asthma and work‐related lower respiratory symptoms were positively associated with the dampness score. Work‐related lower respiratory symptoms showed monotonically increasing odds ratios with ergosterol, a marker of fungal biomass. Other fungal and bacterial indices, particle counts, cat allergen and latex allergen were associated with respiratory symptoms. Our data imply new‐onset of asthma in relation to water damage, and indicate that work‐related respiratory symptoms in hospital workers may be associated with diverse biological contaminants.     

Doxorubicin-loaded cholic acid-polyethyleneimine micelles for targeted delivery of antitumor drugs: synthesis,characterization, and evaluation of their in vitro cytotoxicity

Doxorubicin-loaded micelles were prepared from a copolymer comprising cholic acid (CA) and polyethyleneimine (PEI) for the delivery of antitumor drugs. The CA-PEI copolymer was synthesized via pairing mediated by N,N’-dicyclohexylcarbodiimide and N-hydroxysuccinimide using dichloromethane as a solvent. Fourier transform infrared and nuclear magnetic resonance analyses were performed to verify the formation of an amide linkage between CA and PEI and doxorubicin localization into the copolymer. Dynamic light scattering and transmission electron microscopy studies revealed that the copolymer could self-assemble into micelles with a spherical morphology and an average diameter of <200 nm. The CA-PEI copolymer was also characterized by X-ray diffraction and differential scanning calorimetry. Doxorubicin-loaded micelles were prepared by dialysis method. A drug release study showed reduced drug release with escalating drug content. In a cytotoxicity assay using human colorectal adenocarcinoma (DLD-1) cells, the doxorubicin-loaded CA-PEI micelles exhibited better antitumor activity than that shown by doxorubicin. This is the first study on CA-PEI micelles as doxorubicin carriers, and this study demonstrated that they are promising candidates as carriers for sustained targeted antitumor drug delivery system.     

Effect of strata properties and panel widths on chock performance

The selection of optimum chock (support) capacity is very crucial for a successful longwall mining. The selection of chock capacity depends on the site-specific geotechnical parameters, constraints and longwall panel geometry, which are generally not known in detail in priority. Hence, based on the field and laboratory data, various possible combinations should be analyzed to cater for the unforeseeable mining conditions. This paper discusses the use of numerical model for selecting an appropriate chock capacity based on the site-specific geological and geotechnical information and longwall panel geometry. The fracture mechanisms of immediate and main roofs are also discussed for various panel widths and support capacities. For the models considered, the chock convergence is predicted to increase by about 33% due to the increase in face width from 100 to 260 m. Similarly, the massive roof strata are found to yield higher chock convergence compared to bedded strata.     

A test of independence based on a generalized correlation function

In this paper, we propose a novel test of independence based on the concept of correntropy. We explore correntropy from a statistical perspective and discuss its properties in the context of testing independence. We introduce the novel concept of parametric correntropy and design a test of independence based on it. We further discuss how the proposed test relaxes the assumption of Gaussianity. Finally, we discuss some computational issues related to the proposed method and compare it with state-of-the-art techniques.     

Particle swarm optimization for scheduling batch processing machines in a permutation flowshop

Batch processing machines are capable of processing several jobs in a batch simultaneously. These machines are used in many real-life applications. This paper presents solution approaches to schedule batch processing machines arranged in a permutation flowshop in order to minimize its makespan (or completion time of the last batch). The processing time of each job on all the machines and their sizes are given. Each machine can process a batch of jobs as long as its capacity is not violated. The batch processing time is equal to the longest processing job in the batch. Since the problem under study is NP-hard, commercial mixed-integer solvers may require prohibitively long run time to solve even modest sized problems. Consequently, a particle swarm optimization (PSO) algorithm is proposed. Three heuristics to update the particle’s positions are also proposed. The effectiveness of the proposed PSO algorithm is compared with a commercial solver (which was used to solve a mathematical model) and several heuristics from the literature. The experimental study conducted indicates that the proposed PSO algorithm outperforms both the commercial solver and the heuristics in terms of solution quality. The commercial solver requires longer run times compared to PSO.