Performance evaluation of minimum quantity lubrication by vege- table oil in terms of cutting force, cutting zone temperature, tool wear, job dimension and surface finish in turning AISI-1060 steel

In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication （MQL） has been suggested since a decade ago as a means of addressing the issues of environmental intrusiveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.     

Effect of calcium and light on the germination of <Emphasis Type="Italic">Urochondra setulosa</Emphasis> under different salts

Urochondra setulosa （Trin.） C.E. Hubbard is a coastal halophytic grass thriving on the coastal dunes along the Pakistani seashore. This grass could be useful in coastal sand dune stabilization using seawater irrigation. The purpose of this investigation was to test the hypothesis that Ca^2＋ （0.0, 2.5, 5.0, 10.0 and 50.0 mmol/L） alleviates the adverse effects of KC1, MgSO4, NaC1 and Na2SO4 at 0, 200, 400, 600, 800 and 1000 mmol/L on the germination of Urochondra setulosa. Seed germination was inhibited with increase in salt concentration with few seeds germinated at and above 400 mmol/L concentration. No seed germinated in any of the KC1 treatments. Inclusion of CaC12 substantially alleviated the inhibitory effects of all salts. Germination was higher under photoperiod in comparison to those seeds germinated under complete darkness. Among the CaC12 concentrations used, 10 mmol/L was most effective in alleviating salinity effects and allowing few seeds to germinate at 1000 mmol/L KC1, MgSO4, NaC1 and Na2SO4 solution.     

Polymorphonuclear leukocyte mediated oxidative inactivation of alpha-1-proteinase inhibitor: Modulation by nitric oxide

Alpha-1-proteinase inhibitor activity was studied in presence of resting and activated polymorphonuclear leucocytes. Four different agonists; phorbol myristic acetate, N-formyl-methionyl-leucyl-phenylalanine, opsonised zymosan and arachidonic acid decreased the inhibitor activity by 23.3%, 20%, 12% and 16.6^ respectively. The inhibitor activity was protected by using various free radical scavengers. Catalase and superoxide dismutase both restored activity by about 18%, mannitol by 13% and sodium azide by 17.3%. The inhibitor activity was also protected significantly by pretreatment of polymorphs with L-Arg, a precursor of nitric oxide, before activation. L-Arg was also observed to suppress the generation of superoxide and hydroxyl radical appreciably. The nitric oxide synthase inhibitor, aminoguanidine drastically inhibited the nitrite release and reversed the protection offered by L-Arg to the inhibitor activity. Our results indicate a multifactorial nature of the inactivation process, the culprit species being superoxide, hydrogen peroxide, hydroxyl radical and hypohalides. Nitric oxide seems to scavenge the superoxide radical directly after its formation rather than inhibiting its generation by NADPH oxidase as was believed earlier.     

Status of Vitamin D Receptor Gene Polymorphism and 25-Hydroxy Vitamin D Deficiency with Essential Hypertension

Essential hypertension (EH) is a multifactorial and complex disease with high rate of incidence and associated co-morbidities. Previous studies do not provide unanimous results for the risk of hypertension and association with Fok I genotype frequency and serum vitamin D levels. Hence, this study was undertaken to determine the status of Fok I vitamin D receptor (VDR) gene polymorphism along with vitamin D levels and blood pressure in patients with EH. Four hundred (200 controls and 200 cases of essential hypertension) participants from general Indian population were enrolled in this study. Peripheral blood samples were collected for genotyping Fok I-VDR gene polymorphism using PCR–RFLP method whereas 25-OH vitamin D levels in serum were quantified using high performance liquid chromatography (HPLC). Significantly reduced 25-OH vitamin D levels were observed in patients with EH (24.04 ± 8.62 vs 50.46 ± 15.46) compared to control subjects (p = 0.0001). Homozygous recessive genotype ‘ff’ frequency was increased by 8.06 fold (CI: 3.71–17.47, p = 0.0001) in patients with EH compared to dominant ‘FF’ genotype frequency. In conclusion, recessive ‘ff’ genotype frequency correlates with reduced serum vitamin D levels and results in significantly increased systolic and diastolic blood pressures leading to predisposition of EH.     

Prevalence of multiple antibiotic resistance and R-plasmid inEscherichia coli isolates of hospital sewage of Aligarh city in India

R-plasmids that transfer antibiotic resistance are common in the non-pathogenicEscherichia coli of the gastro-intestinal tract of human beings and domestic animals, which inturn may enter into sewage. Therefore we have isolated 30Escherichia coli isolates from hospital sewage of Aligarh city. These isolates were tested for their resistance and sensitivity against 10 antibiotics. 90% isolates showed resistance against ampicillin and sulphamethizole. Of the total 30E. coli isolates 86.6% were resistant to erythromycin and rifampicin but none of them was resistant to kanamycin and streptomycin. Plasmids (mol. wt. 16.5 mega daltons) were isolated from five differentE. coli strains which harboured only a single plasmid and were characterized on the basis of antibiogram. Moreover, the transformation experiments were also performed to confirm the resistant character on the plasmid. We conclude that multiple drug resistance among most of theE. coli isolates is plasmid borne.     

Health sciences libraries and information services in Bangladesh

Basic problems relating to the status of health sciences libraries and information centers in Bangladesh are highlighted and discussed; strategies for improving the country's health sciences information services are suggested. A survey of libraries is reported, the country's national science and technology information policy is defined, and recommendations for action are proposed.     

Curriculum reform in a global context: a study of teachers in Jordan

The gap between the educational achievements of the comparatively wealthy and those living in poverty is widening world‐wide, with the associated threat to social cohesion. Twenty‐five years of curriculum reform has largely failed in its objective of providing quality, basic education for all. Arguing that successful innovation requires the participation of willing teachers, and associating this idea with the claim that schools are important for social cohesion, this study surveyed 500 Jordanian elementary teachers about their involvement in a programme of curriculum change and their desire to participate. Twelve key informants were interviewed. The reform has raised the qualifications of teachers and increased male teacher numbers but has neither raised overall standards nor improved truancy rates. Tight central control has failed to engage teachers’ allegiance to the changes. Officials blamed failures on schools; head teachers blamed parents, and teachers criticized a policy that left them mediating a curriculum that lacked relevance and failed to engage pupils.