Sintering/shrinkage kinetics of metal injection molded copper brown body

The sintering shrinkage kinetics of metal injection molded copper brown parts was investigated at three different heating rates up to 1050 °C using a high temperature pushrod dilatometer. Non-isothermal and isothermal measurements were simultaneously used in the multivariate non-linear regression analysis to determine the kinetic reaction parameters. A four-step kinetic model was established using “Jander” diffusion equation. Using the rate control sintering, the temperature-time profile for the predefined shrinkage was achieved with respect to time saving. The temperature-time profile was confirmed by performing an experimental run in the production furnace. The metallographic analysis of the microstructure and determination of the sintered density revealed the validation of calculated temperature-time profile.     

Classification of Drinking Water Quality Index and Identification of Significant Factors

Water pipes are considered to be one of responsible sources for the water pollution. Among these sources of water supply, the water pipes are the only source of carrying out fresh or processed water into lakes, ponds and streams etc. In Pakistan, knowledge on the condition of water pipes is scarce as deterioration of water pipes are hardly inspected due to high cost. The aim of the current research was to examine the quality of water pipelines of eight districts of South-Punjab, namely, Mianwali, Khushab, Layyah, Bhakkar, Dera Ghazi Khan, Muzaffargarh, Rajanpur and Rahim Yar Khan. Selected sampling stations were analyzed for physio-chemical parameters such as pH, Total Dissolve Solids (TDS), Sulfate (SO₄), Chlorine (Cl), Calcium (Ca), Magnesium (Mg), Hardness, Nitrate (NO₃), Fluoride (F) and Iron (Fe). The data pertaining water monitoring contain different parameters and seem difficult work for the interpretation of water quality by managing different parameters separately. For this purpose, National Sanitation Foundation Water Quality Index (NSF-WQI) was determined to communicate the quality of water in a simple form. Besides this, groups comprising of similar sampling sites based on water quality characteristics were identified using unsupervised technique. Factor Analysis (FA) has been performed for extracting the latent pollution sources that may cause the more variance in large and complex data. The calculated values of WQI from 1600 sampling stations ranging from 20.73 to 223.74 are divided into five groups; Excellent to Unsuitable class of waters with the average value 62.09 described as good limit for drinking water. Further sampling stations are divided into five optimal clusters selected with suitable k value obtained from Silhouette coefficient. Results of k-means clustering are also verified with natural groups made by WQI. Analysis of multivariate techniques showed several factors to be responsible for the water quality deterioration. It is found out from the FA that three latent factors such as organic pollution, agriculture run-off and urban land use caused 83.30 % of the total variation. Hence, water quality management and control of these latent factors are strongly recommended.     

An investigation into gamma-ray treatment of shellfish using electron paramagnetic resonance spectroscopy

BACKGROUND: Gamma irradiation is a safe method for the decontamination of shellfish, and its technical feasibility and safety have been endorsed (FAO/IAEA/WHO). In order to implement proper food‐processing regulations, the identification of radiation treatment is required. In this study, electron paramagnetic resonance (EPR) spectroscopy was employed to identify the irradiation of seven different types of commonly consumed shellfish. RESULTS: Characteristics (g factor and signal intensity) of the EPR spectra of control and irradiated samples were recorded in order to clarify the gamma‐ray treatment of shellfish. Radiation‐specific signals around g = 2.0038 ± 0.0006 (g₁) and g = 1.9996 ± 0.0002 (g₂ and g₃) were observed for all shellfish samples irradiated with absorbed doses of 3 and 6 kGy. The X‐ray diffraction (XRD) spectra of some shellfish samples were recorded to investigate their mineral profiles. CONCLUSION: The EPR spectroscopic results indicated that carbonate minerals were the source of the paramagnetic species that were produced upon irradiation, entrapped in the shellfish and showed radiation‐specific asymmetric signals whose intensities increased quantitatively with the absorbed radiation dose. The XRD analysis revealed that aragonite and calcite minerals were present in the shells of shellfish. Copyright © 2011 Society of Chemical Industry     

Effects of individual and combined administration of ochratoxin A and aflatoxin B1 in tissues and eggs of White Leghorn breeder hens

BACKGROUND: Mycotoxins, the secondary fungal metabolites, are unavoidable contaminants of human and animal food and feeds. The objectives of this study were to evaluate the effect of concurrent feeding of ochratoxin A (OTA) and aflatoxin B₁ (AFB₁) to breeder hens, upon their deposition in different tissues and eggs. RESULTS: Residues of OTA and AFB₁ in (ng g^?1) were significantly higher in liver followed by kidneys and breast muscles by 22.54 ± 1.48, 4.22 ± 0.93 and 0.56 ± 0.06 for OTA (group fed OTA at 5 mg kg^?1 diet) and 1.44 ± 0.21, 0.25 ± 0.01 and 0.03 ± 0.01 for AFB₁ (group fed AFB₁ at 5 mg kg^?1 diet), respectively. Residues of OTA and AFB₁ in eggs appeared at days 3 and 5 of toxin feeding and disappeared at days 5 and 6 of withdrawal of mycotoxins contaminated feed, respectively. The residues of OTA and AFB₁ were significantly lower in the tissues of hens fed these toxins concurrently compared with the groups fed OTA and AFB₁ independently. CONCLUSIONS: Residues of OTA and AFB₁ appeared in the tissues and eggs of laying hens kept on OTA‐ and AFB₁‐contaminated diets. Concurrent feeding of OTA and AFB₁ to hens significantly decreased the concentration of OTA and AFB₁ residues in the tissues and eggs. Copyright © 2011 Society of Chemical Industry     

Optimal Agricultural Water Allocation for the Sustainable Development of Surface and Groundwater Resources

This paper presents a multiobjective linear program for the optimal allocation of water resources among various crops in a large canal command area of Pakistan. The available surface water in the canal cannot meet the net irrigation requirement (NIR) of various crops, which leads to the overexploitation of groundwater and causes salinity problems. Therefore, an optimal water allocation model was formulated using the simultaneous compromise constraint (SICCON) technique for the sustainable development of surface water and groundwater. Three (03) single objective functions (OFs) and a multiobjective function (MOF) were considered in this study. The MOF combines the single OFs by developing an arrangement among them to both maximize the satisfaction rate for surface water (SR_s) and net economic returns (NER) and minimize the salinity problems. The available surface water (AW) of 1531 Mm³ was allocated among various crops, i.e., wheat, cotton, sugarcane, rice, onion, and sunflower, using the SICCON technique, and the deficit was accounted for with groundwater reserves. The model results showed an average increase of 22% in SR_s and 7.2 million USD in NER_s from surface water allocation compared to the current water allocation practice. Moreover, the salinity levels of the allocated water exceed the threshold limits of onion, sugarcane, and rice crops in the current water allocation system and thereby negatively impact agricultural production. Hence, the model used in this study may support decision-makers in the optimal selection of different crops to be irrigated to maximize the SR_s and NER_s and minimize salinity problems.

     

Insulin elevates hippocampal GABA levels during ischemia. This is independent of its hypoglycemic effect

There are reports that insulin may protect neurons from the effects of ischemia. The mechanisms for this protection are not fully understood. We studied the extracellular levels of glutamate and GABA in insulin-treated animals exposed to transient forebrain ischemia under normoglycemic and hypoglycemic conditions. In vivo microdialysis technique was used to collect extracellular fluid from the CA1 region of the hippocampus. There was a significant increase in GABA levels in the two insulin-treated sub-groups compared with the controls. GABA levels were < 1 pmol/10 microliters in three 10 min collections prior to ischemia in all the groups. It increased from 11.1 +/- 3.5 pmol/10 microliters in the conrol group to 47 +/- 5 (P < 0.001) in the insulin-treated hypoglycemic group and up to 47.2 +/- 9.3+ (P < 0.005) in the insulin-treated normoglycemic group (two-way ANOVA with repeated measures). Ischemia resulted in an increase in the glutamate levels. The glutamate levels returned to baseline within 30 min of the insult. There were no significant differences in the glutamate levels in three groups. The increase in GABA concentrations in the extracellular space may result in the inhibition of CA1 pyramidal neurons. This may be a possible mechanism of neuronal protection in animals treated with insulin (with or without being hypoglycemic) during ischemia.     

Ataxia-telangiectasia and T-cell leukemias: no evidence for somatic ATM mutation in sporadic T-ALL or for hypermethylation of the ATM-NPAT/E14 bidirectional promoter in T-PLL

The ATM gene deficient in ataxia-telangiectasia, a recessive multisystem disease associated with a high risk of lymphomas and leukemias, was found previously to be inactivated in a rare sporadic malignancy, T-cell prolymphocytic leukemia (T-PLL), which is often associated with cytogenetic aberrations of chromosome 14. The ATM gene was shown to sustain frequent loss-of-function mutations in T-PLL tumor cells, consistent with functioning as a tumor suppressor gene in this leukemia. To investigate the possibility of nonmutational or nonrecombinational mechanisms of T-PLL development, we have used bisulfite genomic sequencing to analyze DNA methylation in the putative bidirectional promoter region of the closely linked ATM and NPAT/E14 genes within the CpG island at 11q22-q23. We show that this region is completely demethylated in lymphocytes expressing ATM; however, no extensive hypermethylation was found in 9 T-PLL tumor DNA samples without evidence of ATM/p53 mutations. Because acute T-cell lymphoblastic leukemias (T-ALL) were also observed in ataxia-telangiectasia patients and T-ALL tumor cells contain chromosome 14 abnormalities, 19 presentation samples of T-ALL patients were analyzed for ATM mutations. Although T-ALL patients exhibited rare nucleotide substitutions not previously found in ATM, all were identified in the germ-line, indicating constitutional polymorphisms, potentially confined to ethnic subpopulations. The absence of somatic nucleotide changes in ATM in T-ALL as compared with T-PLL suggests a distinct pattern of genetic events in the development of the two leukemias.     

Propagation of the Multi-Scalar Aggregative Standardized Precipitation Temperature Index and its Application

Water Resources Management - Nowadays, drought monitoring with various probabilistic indices has become common. However, the interpretation and applicability issues of multi-scalar drought indices...