Toward development of optimum specimen designs and modeling of in-plane uniaxial compression testing of aluminum alloy 2024 and AISI 1008 steel sheet material.

Tension-compression testing is commonly conducted to understand and predict springback during a stamping process. However, large strains are generally difficult to achieve during the in-plane compression portion of the test. Proper specimen design and control of frictional forces are necessary for obtaining large strains. This paper describes extensive finite element analyses (FEA) and optimization studies (Phase 1) that were conducted to calibrate the model test assembly for three different buckling modes obtained in uniaxial compression tests of aluminum alloy 2024 and American Iron and Steel Institute (AISI) 1008 steel specimens. In addition to obtaining these three buckling modes correctly, calibrated FEA model predicted forces matched measured forces reasonably well. Also, a good agreement between computed and measured stress-strain data was demonstrated for one compression experiment. In the Phase 2 optimization study, optimum specimen geometries will be developed by using these verified, optimum FEA model test assemblies in three types of compression buckling experiments.

Multivariate statistical analysis of heavy metals in soils of a Pb-Zn mining area, India.

Surface soil samples collected from a Pb and Zn mining area in India were subjected to multi-elemental analysis by using inductively coupled plasma-atomic emission spectrometry. Multivariate statistical methods such as principal component analysis and cluster analysis, coupled with correlation coefficient analysis, were used to analyze the data and to apportion the possible sources of elements in soils of a metal mining area. Soils in this area have elevated heavy metal concentrations especially Pb, Zn, Mn, Cu, As, and Tl. Using principal component (PC) analysis, six components were extracted, out of which two PCs explaining 50.12% of total variance are more important. The first principal component with a high contribution of Ag, As, Be, Cd, Co, Cu, Mg, Mn, Ni, Pb, and Zn was deemed to be technogenic/anthropogenic component, and the second principal component, with high loadings for the five discerning variables (Al, Be, Cr, K, Li), was considered as lithogenic component. The third component having strong loadings of Ba, Ca, K, and Na is supposed to have a mixed origin (lithogenic as well as technogenic). Electrical conductivity and total organic matter were not correlated with any element and also have a strong loading in the fifth component which is probably the biomass and ions present in these soils. The findings of the principal component analysis were also substantiated by the cluster analysis. The present study would not only enhance our knowledge regarding the soil pollution status in the study area but would also provide us information to manage the sources of these elements in the study area.

Associations of cadmium, zinc, and lead in soils from a lead and zinc mining area as studied by single and sequential extractions.

An exploratory study of the area surrounding a historical Pb-Zn mining and smelting area in Zawar, India, detected significant contamination of the terrestrial environment by heavy metals. Soils (n=87) were analyzed for pH, EC, total organic matter (TOM), Pb, Zn, Mn, and Cd levels. The statistical analysis indicated that the frequency distribution of the analyzed parameters for these soils was not normal. The median concentrations of metals in surface soils were: Pb 420.21 µ g/g, Zn 870.25 µ g/g, Mn 696.70 µ g/g, and Cd 2.09 µ g/g. Zn concentrations were significantly correlated with Cd (r=0.867), indicating that levels of Cd are dependent on Zn. However, pH, electrical conductivity and total organic matter were not correlated significantly with Cd, Pb, Zn, and Mn. To assess the potential mobility of Cd, Pb, and Zn in soils, single (EDTA) as well as sequential extraction scheme (modified BCR) were applied to representative (n=23) soil samples. The amount of Cd, Pb, and Zn extracted by EDTA and their total concentrations showed linear positive correlation, which are statistically significant (r values for Cd, Pb, and Zn being 0.901, 0.971, and 0.795, respectively, and P values being <0.001). The correlation coefficients indicate a strong relation between EDTA-extractable metal and total metal. These results appear to justify the use of 'total' metal contents as a useful preliminary indicator of areas where the risks of metal excess or deficiency are high. The EDTA extractability was maximum for Cd followed by Pb and Zn in soils from all the locations. As indicated by single extraction, the apparent mobility and potential bioavailability of metals in soils followed the order: Cd ≥ Pb > > Zn. Soil samples were sequentially extracted (modified BCR) so that solid pools of Cd, Zn, and Pb could be partitioned into four operationally defined fractions viz. acid-soluble, reducible, oxidizable, and residual. Cadmium was present appreciably (39.41%) in the acid-soluble fraction and zinc was predominantly associated (32.42%) with residual fraction. Pb (66.86%) and Zn (30.44%) were present mainly in the reducible fraction. Assuming that the mobility and bioavailability are related to solubility of geochemical forms of metals and decrease in the order of extraction, the apparent mobility and potential metal bioavailability for these contaminated soil samples is Cd > Zn > Pb.

Comparison of two sequential extraction procedures for heavy metal partitioning in mine tailings.

This study aimed at elucidating the fractionation of Cd, Zn and Pb in mine tailings and evaluating the extraction selectivity of different extractants--and thus the efficiency of two sequential extraction procedures. For the purpose of figuring out the applicability of different sequential extraction procedures (SEP's) in Cd, Zn and Pb fractionation in mine tailings, two SEP's (i) modified BCR and (ii) Tessier's scheme were applied to mine tailings (new as well as old). To compare the results obtained by two methods having different number of fractions (four and five respectively), the fractions were rearranged into four "equivalent fractions" defined as acid soluble, reducible, oxidisable and residual. Systematic variations in the "reducible" fraction, i.e. the content of metal in the reducible fractions obtained by Tessier's procedure were, in general, higher than those obtained by BCR scheme. This may be attributed to stronger conditions used in Tessier's scheme to extract this fraction. This shows that the fractions are only empirically (operationally) defined and are not totally exclusive to the specified mineral phase. Percentages of Cd, Zn and Pb extracted in the organic fraction by modified BCR scheme were always higher than those obtained by Tessier's scheme. Based on the fractionation results by both the schemes, it appears that as compared to Cd and Zn, Pb has lower extraction yield in old tailings as compared to new tailings in organic/sulphides bound fraction. This can be explained by the formation of secondary Pb minerals of low solubility, formed by the oxidation of sulphides in old tailings as a result of weathering. Speciation data indicate that Cd has the greatest affinity in the acid soluble fraction, Pb is associated with the reducible fraction and Zn is incorporated into the residual fraction (crystalline silicate matrices) irrespective of the solid matrix type. The metal associations in the oxidizable fraction appear to be matrix specific, i.e., Zn dominates this fraction in new tailings and Pb in old tailings.

Heavy metal uptake and its effect on macronutrients, chlorophyll, protein, and peroxidase activity of Paspalum distichum grown on sludge-dosed soils. Heavy metal uptake and its effect on P. distichum.

This study assessed the heavy metal (Cr, Mn, Ni, Cu, Zn, and Pb) uptake and its effect on biochemical parameters in Paspalum distichum, a wetland plant. Sludge collected from Bhalswa waste dump, New Delhi, was used as heavy metal source and dosed in different proportions viz. 20%, 40%, 60%, and 80% to the garden soil. The plants accumulated metals mostly in belowground organs. The metal accumulation followed the order: Cr>Mn>Cu>Zn>Ni>Pb. The range of heavy metal concentration in tissue of belowground organs after 180 days of growth was 1,778.65-4,288.01 ppm Cr, 828.11-1,360 ppm Mn, 236.52-330.07 ppm Ni, 155.79-282.35 ppm Cu, 27.05-91.16 ppm Zn, and 27.09-50.87 ppm Pb. The biochemical parameters viz. chlorophyll and protein contents and peroxidase (POD) activity exhibited no considerable adverse effect indicating the plants' tolerance towards heavy metals. The high POD activity and synthesis of new protein bands at high sludge-dosed plants were also in support of this fact.

Requirement of protein kinase type I for cAMP-mediated up-regulation of lipid-linked oligosaccharide for asparagine-linked protein glycosylation.

Glycan chains of asparagine-linked (N-linked) glycoproteins play a significant role in protein structure and function, as well as in angiogenesis an essential process for breast or other solid tumor growth. Non-availability of these chains causes incorrect folding of glycoproteins and leads to programmed cell death (i.e., apoptosis) through unfolded protein response (UPR) signaling. Cells actively processing cAMP signals modulate the glycan chain biosynthesis by PKA. Glycosylation of cellular proteins in a PKA type I-deficient CHO mutant 10248 was much reduced when compared with the wild type CHO 10001. The rate of LLO biosynthesis is similar in both cell types but quantitatively it is low in the mutant. Pulse-chase experiments indicated that the t(1/2) for LLO-turnover in CHO 10248 was twice as high as that of the wild type. This correlated with the reduced DPMS activity. The Km for GDP-mannose for the DPMS activity was 3-4 folds higher in the mutant than that of the wild type with or without exogenously added Dol-P. The kcat of DPMS was also reduced in the mutant. In vitro phosphorylation of microsomes from the CHO 10248 by PKA, on the other hand, restored the DPMS activity to the normal level. The LLO biosynthesis also improved significantly in MR1, a revertant of the CHO 10248. The turnover of LLO in MR1 and the glycoprotein profile were also at par with the wild type. Therefore, we conclude that PKA type I plays an important role in modulating the protein N-glycosylation in cAMP responsive cells.

Heavy metal uptake by Scirpus Littoralis Schrad. from fly ash dosed and metal spiked soils.

Scirpus littoralis is a wetland plant commonly found in Yamuna flood plains of Delhi, India. The ability of Scirpus littoralis to take up and translocate five metals- Mn, Ni, Cu, Zn and Pb from fly ash dosed and metal spiked soils were studied under waterlogged and field conditions for 90 days. Scirpus littoralis accumulated Mn, Ni, Cu, Zn and Pb upto a maximum of 494.92, 56.37, 144.98, 207.95 and 93.08 ppm dry wt., respectively in below ground organs (BO) in 90 days time. The metal content ratios BO/soil (B/S) were higher than shoot/soil ratios (T/S) for all the metals, the highest being for Ni. Metal ratios BO/water (B/W) were also higher than shoot/water (T/W) ratios but the B/W ratio was maximum for Zn. The changes in nutrient status (N, P) in soil water and plants were also studied at interval of 30 days. The Pearson's correlation between metal uptake and N, P uptake were calculated. All the metals except Ni showed negative correlation with nitrogen but they were all non-significant. However, P uptake showed positive correlations with all the metals and all were significant at 1% confidence limit.

Molecular epidemiology of tuberculosis in London 1995-7 showing low rate of active transmission.

BACKGROUND: Tuberculosis notification rates for London have risen dramatically in recent years. Molecular typing of Mycobacterium tuberculosis has contributed to our understanding of the epidemiology of tuberculosis throughout the world. This study aimed to assess the degree of recent transmission of M tuberculosis in London and subpopulations of the community with high rates of recent transmission. METHODS: M tuberculosis isolates from all persons from Greater London diagnosed with culture positive tuberculosis between 1 July 1995 and 31 December 1997 were genetically fingerprinted using IS6110 restriction fragment length polymorphism (RFLP) typing. A structured proforma was used during record review of cases of culture confirmed tuberculosis. Cluster analysis was performed and risk factors for clustering were examined in a univariate analysis followed by a logistic regression analysis with membership of a cluster as the outcome variable. RESULTS: RFLP patterns were obtained for 2042 isolates with more than four copies of IS6110; 463 (22.7%) belonged to 169 molecular clusters, which ranged in size from two (65% of clusters) to 12 persons. The estimated rate of recent transmission was 14.4%. Young age (0-19 years) (odds ratio (OR) 2.65, 95% confidence interval (CI) 1.59 to 4.44), birth in the UK (OR 1.55, 95% CI 1.04 to 2.03), black Caribbean ethnic group (OR 2.19, 95% CI 1.15 to 4.16), alcohol dependence (OR 2.33, 95% CI 1.46 to 3.72), and streptomycin resistance (OR 1.82, 95% CI 1.15 to 2.88) were independently associated with an increased risk of clustering. CONCLUSIONS: Tuberculosis in London is largely caused by reactivation or importation of infection by recent immigrants. Newly acquired infection is also common among people with recognised risk factors. Preventative interventions and early diagnosis of immigrants from areas with a high incidence of tuberculosis, together with thorough contact tracing and monitoring of treatment outcome among all cases of tuberculosis (especially in groups at higher risk of recent infection), remains most important.

Tunicamycin inhibits capillary endothelial cell proliferation by inducing apoptosis. Targeting dolichol-pathway for generation of new anti-angiogenic therapeutics.

Bovine adrenal medulla microvascular endothelial cells used in this study undergo cellular proliferation and differentiation upon culturing in vitro as observed both by light and scanning electron microscopy. Cells also respond to the growth promoting activity of serum and basic fibroblast growth factor (FGF2). Flow cytometric analysis of a synchronized culture established that cells take 68 hours to complete one cell cycle spending 36 hours in the G1 phase, 8 hours in the S phase, and 24 hours in the G2 + M phase when cultured in EMEM containing 2% heat-inactivated fetal bovine serum (FBS). At 10% serum, or in the presence of FGF2 (10 ng/ml-100 ng/ml) length of the cell cycle is reduced to 56 hours due to shortening of the G1 phase by 12 hours. Tunicamycin (a glucosamine-containing pyrimidine nucleotide), and an inhibitor of glucosaminyl-1-phosphate (GlcNAc 1-P) transferase, the first step of Glc3Man9GlcNAc2-PP-Dol (OSL) biosynthesis is found to inhibit the endothelial cells proliferation by inducing apoptosis as observed by flow cytometry and DNA laddering. Cell shrinkage, compaction of nuclei, membrane fragmentation, etc., typical of apoptotic response are frequently seen by light microscopy in the presence of tunicamycin. Scanning electron microscopy also exhibited a considerable amount of cell surface blebbing. Accumulation of an immunopositive cell specific asparagine-linked (N-linked) glycoprotein, Factor VIII:C in the absence of Glc3Man9GlcNAc2-PP-Dol in tunicamycin treated cells has been proposed as an apoptotic triggering mechanism under the current experimental conditions.

In vitro activity of ciprofloxacin, sparfloxacin, ofloxacin, amikacin and rifampicin against Ghanaian isolates of Mycobacterium ulcerans.

MICs of ciprofloxacin, sparfloxacin, ofloxacin, amikacin and rifampicin were determined for 14 primary clinical isolates and three reference isolates of Mycobacterium ulcerans by modifying a standard agar dilution method for testing Mycobacterium tuberculosis sensitivity. All these antimicrobials were active against every isolate of M. ulcerans. Sparfloxacin exhibited the highest activity and ofloxacin was the least effective. Rifampicin exhibited the broadest range of activity.

Mannosylphosphodolichol synthase activity is associated with a 32 kDa phosphoprotein.

Failure of actinomycin D to block the activation of Dol-P-Man synthase in isoproterenol-treated capillary endothelial cells, supported that isoproterenol effect was not mediated by active transcription of the Dol-P-Man synthase gene during a short-term beta-adrenoreceptor stimulation. Instead, it was a net effect of protein phosphorylation by cAMP-dependent protein kinase. Using antibody as a probe we have now demonstrated that Dol-P-Man synthase activity is associated with a 32 kDa ER phosphoprotein.

Expression of Glc3Man9GlcNAc2-PP-Dol is a prerequisite for capillary endothelial cell proliferation.

Protein N-glycosylation has been proposed to be intimately involved in the migration, proliferation and differentiation of endothelial cells. Using a synchronized, non-transformed capillary endothelial cell line from bovine adrenal medulla as a model, and the N-glycosylation inhibitor, tunicamycin, we have elucidated the molecular basis of the dolichol pathway in the angiogenic process. The synchronized culture required approximately 68 hrs. to complete one cell cycle, cells spending nearly 36 hrs. in G1 phase, 8 hrs. in S phase and 24 hrs. in G2 + M phase when maintained in 2% fetal bovine serum (heat-inactivated). The cell cycle however, was shortened due to a reduction of the G1 phase by 12-16 hrs. when the serum concentration was increased to 10%, or when beta FGF (1 or 10 nanogram) was added into the culture media containing 2% serum. Light microscopy and scanning electron microscopy both supported these proliferative responses. Serum concentration below 2% arrested cell proliferation and induced capillary lumen-like structure formation with 48 hrs. Expression of the blood clotting antigen factor VIII:C (a M(r) 270,000 dalton N-linked glycoprotein and a marker of our endothelial cells) preceded the endothelial cell proliferation and established a temporal relationship. Tunicamycin, an inhibitor of Glc3Man9GlcNAc2-PP-Dol biosynthesis, a prerequisite for N-linked protein glycosylation in the ER-inhibited the cell growth and proliferation in a time and dose-dependent manner with a concomitant accumulation of immunopositive, non-glycosylated factor VIII:C in the conditioned media. Tunicamycin also caused surface blebbing and induction of programmed cell death (PCD)(apoptosis) within 32 hrs. Absence of cellular growth and proliferation, surface blebbing and the induction of PCD in the presence of tunicamycin, provided conclusive evidence that normal expression of Glc3Man9GlcNAc2-PP-Dol is an essential event for capillary proliferation during angiogenesis.

Angiogenesis: characterization of a cellular model.

Endothelial cell proliferation and differentiation into blood capillaries (i.e., angiogenesis) are essential for growth and development, wound healing, osetogenesis, etc. But abnormal angiogenesis during tumor progression could lead to serious consequences. Angiogenesis is a complex biochemical process, and is often difficult to study the molecular mechanism in vivo due to interference by multitude of factors. Here, I present a non-transformed capillary endothelial cell line as a model which has been extensively characterized morphologically and biochemically to study the fundamentals of the angiogenic process. Studies completed in our laboratory also evidenced that expression of Glc3Man9GlcNAc2-PP-Dol is intricately connected with the balance between the cellular proliferation and apoptosis during angiogenesis.

Rapid detection of multidrug-resistant tuberculosis.

Transmission of multidrug-resistant strains of Mycobacterium tuberculosis (MDR-TB) presents a serious problem for infection control in hospitals, particularly in the context of co-infection with the human immunodeficiency virus (HIV). We report on the use of molecular genetic tools to allow rapid assessment of samples from patients potentially infected with MDR-TB. Sputum and bronchoalveolar lavage samples were obtained from two HIV-positive patients with suspected tuberculosis, who had previous contact with a known MDR-TB index case. Polymerase chain reaction (PCR) was used directly on clinical samples to amplify genetic loci associated with rifampicin resistance (rpoB), and strain-specific polymorphisms (the direct repeat (DR) region). Drug resistance was determined using a commercially available kit for detection of point mutations in the rpoB gene (Inno-Lipa RifTB; Innogenetics, Belgium), and confirmed by nucleotide sequencing. Strain variation was determined using the spoligotyping method, based on the presence or absence of variable linker sequences within the DR region. In one patient, infection with a MDR strain identical to that of a known index case was demonstrated. A second patient, although positive for M. tuberculosis, was found to be infected with a rifampicin-sensitive strain. Results were obtained within 48 h, allowing appropriate treatment to be initiated and infection control measures to be implemented. PCR-based tests for strain-typing and for identification of rifampicin resistance provide important tools for identifying patients with MDR-TB and for rapid monitoring of potential nosocomial spread of MDR-TB. Prompt confirmation or exclusion of possible transmission allows early clinical intervention to prevent future outbreaks of multidrug-resistant M. tuberculosis.

Experimental evaluation of possible new short-term drug regimens for treatment of multibacillary leprosy.

Groups of nude mice, with both hind footpads infected with 10(8) Mycobacterium leprae organisms, were treated with 4-week courses of different drug combinations. The effect treatment on each group was evaluated by subinoculating footpad homogenates from the treated mice into groups of normal and nude mice for subsequent regrowth, assessed 1 year later. A combination of rifampin (RMP) with clarithromycin (CLARI), minocycline (MINO), and ofloxacin (OFLO) resulted in the complete killing of M. leprae after 3 weeks of treatment. A combination of sparfloxacin (SPAR) and RMP also resulted in a similar bactericidal effect after 3 weeks of treatment. Other drug combinations showed variable effects. Very little or no effect was observed with any regimen if the treatment was given for less than 2 weeks. World Health Organization (WHO) multidrug therapy (MDT) given for 8 weeks was as effective as the two combinations described above. The results suggest that multidrug combinations consisting of RMP-OFLO (or SPAR)-CLARI (and/or MINO) are as effective as the WHO MDT for the treatment of experimental leprosy. Moreover, they imply that these combinations, which were found to be active in a 4-week experimental treatment protocol, could be administered as treatment to patients for a period of time shorter than the present 2-year regimen without a loss of effectiveness.

Biphasic estrogen response on bovine adrenal medulla capillary endothelial cell adhesion, proliferation and tube formation.

Abnormal angiogenesis underlies many pathological conditions and is critical for the growth and maintenance of various types of tumors, including hormone-dependent cancers. Since estrogens are potent carcinogens in humans and rodents, and are involved in regulating angiogenesis, this study was designed to examine the effect of estrogen on the behavior of an established bovine capillary endothelial cell line, a simple and physiologically relevant model of the capillary wall. The results demonstrate that 17beta-estradiol (E2), at different conditions, exerts both stimulatory and inhibitory effects on endothelial cell adhesion, proliferation and tube formation in vitro. Utilizing a cellular attachment assay, chronic exposure to nanomolar concentrations of E2 (i.e. 1 and 10 nM) increased endothelial cell adhesion significantly compared to vehicle treated controls. Cellular adhesion was inhibited by micromolar concentrations of E2. Cell count, PCNA immunohistochemistry and Western blot analysis demonstrated enhanced cell proliferation at low E2 concentration in estrogen-deplete medium. Inhibition of cellular proliferation was observed in both estrogen-replete and deplete medium at higher E2 concentrations (i.e. 1 and 10 microM). Furthermore, in vitro tube formation increased up to 3.0 fold in the presence of 10 nM and higher E2 concentrations. The present observations indicate that in vitro regulation of capillary endothelial cell adhesion, proliferation and capillary tube formation by estrogen, are dose dependent.

Beta-adrenoreceptors of multiple affinities in a clonal capillary endothelial cell line and its functional implication.

beta-Adrenoreceptor has been studied in a clonal capillary endothelial cell line established from the vascular bed of the bovine adrenal medulla. [3H]Dihydroalprenolol ([3H]DHA) binding to the isolated plasma membranes from these cells has demonstrated the presence of beta-adrenoreceptors with two different affinities. The dissociation constants (Kd) have been found to be 0.27 +/- 0.09 x 10(-9) M and 2.96 +/- 0.31 x 10(-9) M, respectively with the corresponding Bmax of 5.1 +/- 0.05 and 70.0 +/- 0.2 pmol/mg protein, respectively. Inhibition of [3H]DHA binding to the beta-receptor by atenolol (a beta 1-antagonist) and ICI 118,551 (a beta 2-antagonist) has suggested that the IC50cor (= Ki) for atenolol and ICI 118,551 for high affinity site are 0.08 +/- 0.03 x 10(-12) M and 0.25 +/- 0.08 x 10(-12) M, respectively. This, therefore, indicates that both atenolol and ICI 118,551 are able to displace the bound ligand effectively but the beta 1-selective antagonist atenolol is 3 times more potent than its beta 2 counterpart, ICI 118,551. Displacement of [3H]DHA binding to the endothelial cell plasma membrane by the agonists isoproterenol, epinephrine and norepinephrine has established a relative order of Ki for these agents as isoproterenol (0.56 +/- 0.19 x 10(-9) M) < epinephrine (0.77 +/- 0.26(-9) M) > or = norepinephrine (0.71 +/- 0.24 x 10(-9) M) for the high affinity site. The corresponding values for the low affinity site, however, are 4.62 +/- 0.64 x 10(-9) M, 6.21 +/- 0.86 x 10(-9) M and 5.90 +/- 0.82 x 10(-9) M, respectively for the same agonists. Increased intracellular cAMP accompanied with cellular proliferation in the presence of isoproterenol has suggested not only the coupling of beta-adrenoreceptors to the adenylate cyclase system but also its involvement in endothelial cell proliferation.

Abnormal pattern of lung functions in rubber factory workers.

The influence of suspended particulate matter, benzo(e) pyrene, benzo(e) pyrene and benzo(a) anthracene concentration on pulmonary lung functions ie, residual volume, total lung capacity, residual volume/total lung capacity, forced residual capacity were studied in 667 rubber factory workers during 1990-91. The respirable fraction of the particulate size (< 0.5 micron) showed high mean concentration of suspended particulate matter, benzo(a) pyrene, benzo(e) pyrene and benzo(a) anthracene in the compounding section (group III), when compared with vulcanising (group II) and packing loading (group I) units. While comparing the lung functions amongst these groups, the higher results of residual volume, residual volume/total lung capacity ratio, forced respiratory capacity and lower values of total lung capacity were observed in group III workers as compared with other two groups. And also these results seem to be correlated with the high pollutant concentrations to which group III workers were exposed, and reflect a clear combination of obstructive and restrictive pattern of lung functions in them.