Experimental observation of the dual effect of pores in liquid spreading over porous substrates, whereby liquid movement is facilitated as well as restricted is presented based on spreading of ...micro-liter-sized liquid drops on substrates that have saturated (filled) millimeter-sized pores. The drops were put on porous and nonporous parts of solid substrate. The substrate was then rotated in vertical direction and the resulting motion of drops was recorded by a video camera. The analysis of the recorded images revealed that depending on whether the drop edge is moving toward the pore or away from the pore, the pore acts as accelerator or brake for the drop edge. This dual nature of the saturated pores can be ascribed to the attraction between the liquid in the drop and the liquid inside the pore. Qualitative changes in the morphology of the drop as it slides over saturated pores are also presented to highlight the process. This dual effect of pores is expected to play a major role in processes such as flow through a trickle bed of porous catalyst where it manifests itself in increased wetting efficiencies as well as pronounced hysteresis Khanna, R., Nigam, K.D.P., 2002. Partial wetting in porous catalyst: wettability and wetting efficiency. Chemical Engineering Science 57, 3401–3405; Maiti et al., 2004. Enhanced liquid spreading due to porosity. Chemical Engineering Science 59, 2817–2820; 2005. Trickle-bed reactors: Porosity induced hysteresis. Industrial and Engineering Chemistry Research, in press..
Betel nut of Areca catechu is chewed by millions of people for increased capacity to work and stress reduction, but it contains arecoline that causes hypothyroidism. The aim is to investigate the ...role of arecoline on thyroid activity in cold stress in mice. Arecoline treatment (10 mg/kg body wt/day, for 7 d) caused a reduction in thyroid weight and ultrastructural degeneration of thyro-follicular cells with depletion of T
3
and T
4
levels compared with the control mice. Cold stress (4 °C for 2 h, twice daily, for 7 d) stimulated thyroid activity ultrastructurally with an elevation of T
3
and T
4
levels. Arecoline treatment in cold stress suppressed thyroid activity by showing reversed changes to those of cold stress. In contrast, TSH concentrations were consistently increased under all experimental conditions. The findings suggest that cold stress causes hyperthyroidism which arecoline can ameliorate in mice.
This study examined the effect of sodium fluoride, a water pollutant important through the world, including India, on testicular steroidogenic and gametogenic activities in relation to testicular ...oxidative stress in rats. Sodium fluoride treatment at 20
mg/kg/day for 29 days by oral gavage resulted in significant diminution in the relative wet weight of the testis, prostate, and seminal vesicle without alteration in the body weight gain. Testicular Δ
5,3β-hydroxysteroid dehydrogenase (HSD) and 17β-HSD activities were decreased significantly along with significant diminution in plasma levels of testosterone in the fluoride-exposed group compared to the control. Epididymal sperm count was decreased significantly in the fluoride-treated group and qualitative examination of testicular sections revealed fewer mature luminal spermatozoa in comparison to the control. The seminiferous tubules were dilated in treated animals. Fluoride treatment was associated with oxidative stress as indicated by an increased level of conjugated dienes in the testis, epididymis, and epididymal sperm pellet with respect to control. Peroxidase and catalase activities in the sperm pellet were decreased significantly in comparison to the control. The results of this experiment indicate that fluoride at a dose encountered in drinking water in contaminated areas exerts an adverse effect on the male reproductive system and this effect is associated with indicators of oxidative stress.
Arecoline has biomedical importance, but it has untoward side effects on endocrine functions. The aim is to investigate its role on adrenal activity under thermal stress by ultrastructural and ...hormonal parameters in mice. Cold (4 °C) or heat (37 °C) stress, or arecoline (10 mg/kg body wt), each for 7 days in cold or heat stress stimulated adrenocortical activity ultrastructurally with an elevation of corticosterone level. Adrenomedullary activity was suppressed in cold stress with depletion of catecholamine levels. In heat stress, adrenomedullary activity was stimulated ultrastructurally with an elevation of catecholamine levels. Arecoline treatment alone, or in cold or heat stress suppressed adrenomedullary activity, judged by ultrastructural and hormonal parameters. Arecoline treatment caused hypoglycemia with an elevation of glycogen level, but cold or heat stress, or arecoline treatment in thermal stress caused hyperglycemia, with a fall in glycogen profile. Thus, arecoline in thermal stress plays a dual role on adrenal function and glucose-glycogen homeostasis in mice.
Strengthening of prestressed girder using FRP has rarely been performed because prestressed girder has excellent strength under service load in both tension and compression. In this study, ...retrofitting of a 59-year-old prestressed bridge of Indian railway at Ratlam has been executed in which multiple vertical cracks visualized in tension zone and surface deterioration were observed. Due to this, deterioration speed of the trains over the bridge was restricted up to 20 km/h. The PSC girders of the bridge were strengthened by using prestressed carbon fiber. Serviceability of the structure was monitored before strengthening and after strengthening of the bridge girder. Deflections and natural frequencies after strengthening of girder were monitored for 481 days to ascertain the improvement and consistency in behavior of girder. After strengthening, the considerable decrement in deflection was noted by dint of the speed limit of the train which is recommended to increase up to 100 km/h.
A mathematical model is proposed to analyze the mass transfer limitations in phenol biodegradation using
Pseudomonas
putida immobilized in calcium alginate. The model takes into account internal and ...external mass transfer limitations, substrate inhibition kinetics and the dependence of the effective diffusivity of phenol in alginate gel on cell concentration. The model is validated with the experimental data from batch fermentation. The effect of various operating conditions such as initial phenol concentration, initial cell loading, alginate gel loading on the biodegradation of phenol is experimentally demonstrated. Phenol degradation time is found to decrease initially and reach stationary value with increase in cell loading as well as gel loading. The model predicts these trends reasonably well and shows the presence of external mass transfer limitations. A new concept of effectiveness factor is introduced to analyze the overall performance of batch fermentation.
Fluoride contamination of drinking water can disrupt male gametogenesis and steroidogenesis and induce testicular oxidative stress. Treatment of rats with sodium fluoride at the dose of 20
mg/kg/day ...for 28 days resulted in significant diminution of testicular Δ
5,3β-hydroxysteroid dehydrogenase (HSD) and 17β-hydroxysteroid dehydrogenase (HSD) activities and low plasma levels of testosterone, follicular stimulating hormone (FSH) and leutinizing hormone (LH). Spermatogenesis inhibited after sodium fluoride treatment has been assessed here by the quantification of different generation of germ cells like spermatogonia A (ASg), preleptotene spermatocyte (PLSc), midpachytene spermatocyte (MPSc) and step 7 spermatid (7Sd) at stage VII of seminiferous epithelial cycle. Furthermore, fluoride treatment was associated with low activities of testicular, prostatic and epididymal catalase (CAT), superoxide dismutase (SOD) and peroxidase along with elevation of malondialdehyde (MDA) and conjugated dienes (CD) in those tissues. Co-administration of calcium and Vitamin-E with fluoride resulted in a significant recovery from testicular disorders and oxidative stress in the testis and male accessory sex organs. The results of this study demonstrate that fluoride exposure, at the dose available in drinking water in contaminated areas, led to inhibition of testicular gametogenesis and steroidogenesis in association with oxidative stress in the testis and male accessory sex organs, which are protected significantly by dietary agents like Vitamin-E and calcium.
Arecoline is known to cause endocrine dysfunction. In the current article role of arecoline on pineal-testis activity was investigated in hypothyroid rats induced by propylthiouracil (PTU). PTU ...treatment caused thyroid dysfunction ultrastructurally with a fall in T
3
and T
4
levels followed by a rise of thyroid stimulating hormone (TSH) level. Pineal activity was impaired by PTU treatment, as evident from degenerated synaptic ribbons and mitochondria of the pinealocytes with depletion of pineal and serum N-acetyl serotonin and melatonin levels. Leydig cell function was suppressed, evident from reduced smooth endoplasmic reticulum and depletion of testosterone level. Sex accessories function was impaired by showing scanty rough endoplasmic reticulum with depletion of fructose and sialic acid levels. Arecoline treatment that caused pineal dysfunction and testicular stimulation in control rats, suppressed both pineal and testis functions after PTU treatment. The findings suggest that arecoline inhibits pineal-testis function in experimentally induced hypothyroid rats.
