475 research outputs found
Nondestructive Testing Method for Finding out the Defects in a Composite Liner
A composite liner of carbon phenolic has been inspected by ultrasonic, X-ray radiography andX-ray computed tomography (CT) to find defects like delaminations, debonds, voids, foreign inclusions, etc.The geometry, detection of multiple defects and porosity of the liner make ultrasonic testing (pulse-echo anddrycoupling) difficult for inspection. X-ray radiography being a non-contact technique finds multiple defectsbut compresses the structural information of 3-D volume into a 2-D image and interferes with overlyingand underlying areas of the object. X-ray CT generates an image of a thin and cross-sectional slice ofan object. R e linear attenuation coefficients in terms of Hounsfield values have been measured, comparedand correlated with CT images at the contrasts observed. 3-D images can be generated by stacking2-D cross-sectional images of the slices. These 3-D images can be cut at any angle of choice for mappingthe extent of delaminated/debonded areas. This type of information is difficult to obtain with conventionalnon-destructive testing techniques
ANTI CONVULSANT EFFECT OF NIFEDIPINE, DIAZEPAM AND IN COMBINATION ON MES INDUCED EPILEPSY IN RATS
Background: The role of calcium in the process of epileptogenesis and neurotoxicity and excitotoxicity during status epilepticus is involved. In fact, epileptiform bursts are often associated with influx of calcium ion into the nerve cells and a decrease in the extracellular concentration of calcium precedes the onset of seizures. Aim: To investigate the activity of nifedipine, the dihydropyridine calcium channel blocker, diazepam, the benzodiazepine anti- convulsant of established efficacy and their combinations against rat models of MES induced tonic seizure. Method: Wister albino rats of either sex, weighing between 150-220 gm were used for maximal electroshock method. Rats were divided into 10 groups, in each group n=6 total N=60.Group 1: Control, Group 2-4:Nifedipine 2, 4 and 8 mg/kg accordingly, Group 5-7: Diazepam 1,2 and 4 mg/kg accordingly, Group 8:Nifedipine (3.3mg) + Diazepam (3mg), Group 9:Nifedipine (6.6mg) + Diazepam (3mg), Group 10: Phenytoin (25mg/kg). The Controls in the central panel was set at 120 mA current. The Start-Reset knob was switched in the reset position with time of 0.2 seconds was set. The following parameters were observed. Latent period of convulsions, duration of flexion, tonic hind limb extension, posttictal sleep. Results: Nifedipine in doses of 4 and 8 mg / Kg., diazepam in all doses (1, 2 and 4 mg / Kg.) and their combinations were significantly reducing the duration of tonic hind limb extension (THLE). Only Nifedipine in doses of 2 mg / Kg. had no significant change in duration of THLE in comparison to Normal saline. The effect of Nifedipine 8 mg / Kg. on reducing the duration of THLE, indicative its anti-seizure activity on MES seizure was comparable to Diazepam in the dose of 1 mg / Kg. The MES-induced anti-seizure activity of Diazepam in doses of 1 mg / Kg. It was significantly less than Diazepam in doses of 2 and 4 mg / Kg or from the combination doses. Diazepam in 4 mg / Kg. dose was equally effective as the combination. But its effect was also equi-effective with Phenytoin. Conclusion: Nifedipine alone is inferior to diazepam in generalized tonic-clonic seizure and their combination is not having superadditive effect.
Key words: Calcium channel blockers; Diazepam; Epilepsy; Maximum electrical shock
ANTI CONVULSANT EFFECT OF NIFEDIPINE, DIAZEPAM AND IN COMBINATION ON MES INDUCED EPILEPSY IN RATS
Background: The role of calcium in the process of epileptogenesis and neurotoxicity and excitotoxicity during status epilepticus is involved. In fact, epileptiform bursts are often associated with influx of calcium ion into the nerve cells and a decrease in the extracellular concentration of calcium precedes the onset of seizures. Aim: To investigate the activity of nifedipine, the dihydropyridine calcium channel blocker, diazepam, the benzodiazepine anti- convulsant of established efficacy and their combinations against rat models of MES induced tonic seizure. Method: Wister albino rats of either sex, weighing between 150-220 gm were used for maximal electroshock method. Rats were divided into 10 groups, in each group n=6 total N=60.Group 1: Control, Group 2-4:Nifedipine 2, 4 and 8 mg/kg accordingly, Group 5-7: Diazepam 1,2 and 4 mg/kg accordingly, Group 8:Nifedipine (3.3mg) + Diazepam (3mg), Group 9:Nifedipine (6.6mg) + Diazepam (3mg), Group 10: Phenytoin (25mg/kg). The Controls in the central panel was set at 120 mA current. The Start-Reset knob was switched in the reset position with time of 0.2 seconds was set. The following parameters were observed. Latent period of convulsions, duration of flexion, tonic hind limb extension, posttictal sleep. Results: Nifedipine in doses of 4 and 8 mg / Kg., diazepam in all doses (1, 2 and 4 mg / Kg.) and their combinations were significantly reducing the duration of tonic hind limb extension (THLE). Only Nifedipine in doses of 2 mg / Kg. had no significant change in duration of THLE in comparison to Normal saline. The effect of Nifedipine 8 mg / Kg. on reducing the duration of THLE, indicative its anti-seizure activity on MES seizure was comparable to Diazepam in the dose of 1 mg / Kg. The MES-induced anti-seizure activity of Diazepam in doses of 1 mg / Kg. It was significantly less than Diazepam in doses of 2 and 4 mg / Kg or from the combination doses. Diazepam in 4 mg / Kg. dose was equally effective as the combination. But its effect was also equi-effective with Phenytoin. Conclusion: Nifedipine alone is inferior to diazepam in generalized tonic-clonic seizure and their combination is not having superadditive effect.
Key words: Calcium channel blockers; Diazepam; Epilepsy; Maximum electrical shock
EFFECT OF LEAD ON MALE REPRODUCTION IN EXPERIMENTAL ANIMAL MODEL
Introduction: In early 1960\u27s, there is a first evidence of the toxic effects ionizing radiation on elevated oxygen levels in aerobes and proposed that oxygen toxicity is due to free radical formation. An alteration between oxidants and antioxidants in favour of the oxidants, potentially leading to damage is termed \u27oxidative stress\u27. Lead and cadmium do not have any detectable beneficial biological roles rather it produces detrimental effects on biochemical, physiological and behavioral dysfunctions. Even a little lead poisoning can cause serious health problems, and at very high levels, it can be fatal. Mainly it affects the heamopoeitc system, Liver, Kidney, Cardiovascular system and reproductive system. Methodology: Experimental rats, injected intraperitoneally with lead acetate for 15 days at the dosage of 50, 100 mg/kg/day body weight and compared to control rats injected with deionized distilled water instead. At the end of study testis were removed and right testis was used for testicular antioxidant Malandealdehyde (MDA) levels estimation by Thiobarbituric acid reactive substance assay and left testis was used for histopathological analysis. Unpaired t test and ANOVA was used for statistical analysis. Results : The MDA (nmole /gm tissue) levels in control, lead 50mg, lead 100mg groups were 12.16±0.4, 17.06±0.16 and 18.11±0.13. Histopathology examination Lumen showing decreased sperm count and maturation. Some of the lumens showing absence sperm maturation. Conclusion: Study on lead-exposed rat testis have shown that reduction of spermatogenesis formation and sperm maturation. Increased MDA levels indicate that it may be due to oxidative stress. The toxicity of lead was noted at level ≥50mg/kg.
Key words: Lead; Lipid peroxidation; Male reproduction; Testicular histology
Anticonvulsant effect of nifedipine, dizepam and in combination on pentylenetetrazol induced experimental models of epilepsy on albino rats
Background: In many patients, the presently available antiepileptic drugs such as phenobarbital, phenytoin, benzodiazepines, sodium valproate, etc., are unable to control seizures efficiently and the problem of adverse effects has also not been circumvented completely and approximately 30% of the patients continue to have seizures with current antiepileptic drugs therapy. Hence, search should continue to develop newer, more effective, and safer neuro-protective agents for treatment of epilepsy. Aim of the study was to investigate the activity of nifedipine, the dihydropyridine calcium channel blocker, diazepam, the benzodiazepine anti- convulsant of established efficacy and their combinations against rat models of pentylenetetrazol (PTZ) induced convulsions. Method: Wister albino rats of either sex, weighing between 150-220gm were used. Rats were divided into 10 groups, in each group n=6 total N=60.Methods: PTZ was administration 30 min after test drug administration. Intraperitoneal injection of PTZ at the dose of 80mg/Kg body weight were administered to the rats to produce chemically-induced seizure. The effect of nifedipine and diazepam were assessed on such seizure model. The onset and duration of clonic convulsion were recorded.Results: The onset time of PTZ-induced clonic convulsion was significantly prolonged with the Nifedipine in the doses of 4mg and 8mg per Kg. in comparison to nifedipine in dose of 2mg per Kg. The interesting observation was that while Diazepam in 1mg/Kg. dose significantly (P<0.05) prolonged the onset time, there was significant decrease (P <0.001) in the onset time of PTZ-induced clonic convulsion with diazepam in doses of 2 and 4mg per Kg. in comparison to Diazepam 1mg per Kg. But the combination of diazepam 2.5 mg and Nifedipine 2.6mg and 5.3mg exhibited significant prolongation of the onset time. Diazepam 1 and 2mg per Kg was found to be equally effective in reduction of convulsion time, while 4mg dose showed more reduction of convulsion time. The combination of diazepam and nifedipine showed no better reduction in the convulsion time and also valproic acid in doses of 135mg. Kg.Conclusions: Nifedipine (3-5mg/Kg) and diazepam (2.5mg/Kg.) combination delayed the onset of convulsion. Diazepam 2mg / Kg. alone was effective in reduction of duration of convulsion. The combination dose having 2.6mg of nifedipine showed comparable protection with valproic acid 135mg per Kg. while the combination having 5.3mg of nifedipine showed significantly better protection.Â
EFFECT OF LEAD ON MALE REPRODUCTION IN EXPERIMENTAL ANIMAL MODEL
Introduction: In early 1960's, there is a first evidence of the toxic effects ionizing radiation on elevated oxygen levels in aerobes and proposed that oxygen toxicity is due to free radical formation. An alteration between oxidants and antioxidants in favour of the oxidants, potentially leading to damage is termed 'oxidative stress'. Lead and cadmium do not have any detectable beneficial biological roles rather it produces detrimental effects on biochemical, physiological and behavioral dysfunctions. Even a little lead poisoning can cause serious health problems, and at very high levels, it can be fatal. Mainly it affects the heamopoeitc system, Liver, Kidney, Cardiovascular system and reproductive system. Methodology: Experimental rats, injected intraperitoneally with lead acetate for 15 days at the dosage of 50, 100 mg/kg/day body weight and compared to control rats injected with deionized distilled water instead. At the end of study testis were removed and right testis was used for testicular antioxidant Malandealdehyde (MDA) levels estimation by Thiobarbituric acid reactive substance assay and left testis was used for histopathological analysis. Unpaired t test and ANOVA was used for statistical analysis. Results : The MDA (nmole /gm tissue) levels in control, lead 50mg, lead 100mg groups were 12.16±0.4, 17.06±0.16 and 18.11±0.13. Histopathology examination Lumen showing decreased sperm count and maturation. Some of the lumens showing absence sperm maturation. Conclusion: Study on lead-exposed rat testis have shown that reduction of spermatogenesis formation and sperm maturation. Increased MDA levels indicate that it may be due to oxidative stress. The toxicity of lead was noted at level ≥50mg/kg.
Key words: Lead; Lipid peroxidation; Male reproduction; Testicular histology
Selfies Can Help Brazil Create a Super Supplementary Pension
Brazilian policy makers and researchers have discussed the introduction of a complementary pension system to complement the Regime Geral de Previdência Social (RGPS), specially for those that want a retirement income above the RGPS ceiling. This article first recommends that the complementary system must be SUPER (Simple, Universal, Portable, Efficient with low cost and Robust Regulatation). It then proposes the adoption of a financial innovation called SeLFIES (Standard-of-Living, Forward-starting, Income-only Securities), as the default investment option for a modern capitalization regime. Brazil presents an interesting opportunity to be the first country to adopt and implement SeLFIES given the initial conditions, especially the innovations introduced in the market for government bonds. This financial innovation would help the Brazilian government address two challenges simultaneously: improve retirement security (by including even the most financially illiterate people and those in the informal sector in retirement plans) and boost infrastructure financing.Brazilian policy makers and researchers have discussed the introduction of a complementary pension system to complement the Regime Geral de Previdência Social (RGPS), specially for those that want a retirement income above the RGPS ceiling. This article first recommends that the complementary system must be SUPER (Simple, Universal, Portable, Efficient with low cost and Robust Regulatation). It then proposes the adoption of a financial innovation called SeLFIES (Standard-of-Living, Forward-starting, Income-only Securities), as the default investment option for a modern capitalization regime. Brazil presents an interesting opportunity to be the first country to adopt and implement SeLFIES given the initial conditions, especially the innovations introduced in the market for government bonds. This financial innovation would help the Brazilian government address two challenges simultaneously: improve retirement security (by including even the most financially illiterate people and those in the informal sector in retirement plans) and boost infrastructure financing
CORRELATION OF CLINICAL AND LABORATORY ASPIRIN RESISTANCE: A PILOT STUDY
Aspirin resistance may be biochemical or clinical. Data related to the presence of aspirinresistance in the Indian population is scarce. We conducted a cross sectional study toaddress the issue of clinical aspirin non responsiveness and to assess the associationbetween inhibition of platelet aggregation, clinical risk factors and occurrence of vascularevents. We studied platelet aggregation by optical aggregometry in 20 patients on aspirin.No patient was found to be aspirin-resistant on the basis of previously defined criteria.This led us to relook at the current cut offs for resistance, and an analysis of 60 normalpatients showed lower cut off values suggesting ethnic variability. The data wasreanalyzed using these cutoffs. An association between poor clinical aspirin response,older age, male sex, smoking and dyslipidemia was found, suggesting a trend, though notsignificant. 25% of patients had vascular events on aspirin suggesting clinical aspirinresistance. A lower cut off value for aspirin resistance in normal Indians may be neededto detect true prevalence of this entity. In patients with multiple atherothrombotic riskfactors lab detection of resistance may be useful in identifying patients with high risk forrecurrent vascular events. This may help to modify antiplatelet therapy to preventvascular events
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