End-stage renal disease patients on hemodialysis: a study from a tertiary care center in a developing country

The exact number of patients with chronic renal failure requiring renal replacement therapy in developing world is not known. Unlike the developed world, most developing countries lack renal registries. This study was initiated to know demographic and clinical data of end-stage renal disease (ESRD) patients presenting to maintenance hemodialysis (MHD) at a government funded tertiary care centre in a developing country. A prospective analysis of all new ESRD patients attending to hemodialysis at our centre from 2004 to 2007 had been done. There were 237 new hemodialysis patients during a three-year period. Males were 153 and females were 84, with the mean age 44.92 years. Diabetes mellitus (31.22%) was the most common cause of ESRD. Only 29.95% of patients had education on renal replacement therapy. 65.40% patients had emergency hemodialysis. Internal jugular catheter was the most common form of vascular access at initiation of hemodialysis. Arteriovenous fistula was secured in 29.95% of patients at presentation. Catheter-related infection appeared in 13.55% of patients on catheter. The most common infection in dialysis patients was urinary tract infection (37.14%). Renal transplantation was opted by 9.7% patients and continuous ambulatory peritoneal dialysis in 20.25% and 103 (43.45%) were lost to follow up. The rest (8.86%) continued on MHD. There were 42 (17.72%) deaths over a three-year period. The present study provided the information of the practice of hemodialysis, its population characteristics and outcomes from a developing country.     

Cocoa Agronomy,Quality, Nutritional,and Health Aspects

The history of cocoa and chocolate including the birth and the expansion of the chocolate industry was described. Recent developments in the industry and cocoa economy were briefly depicted. An overview of the classification of cacao as well as studies on phenotypic and genetic diversity was presented. Cocoa agronomic practices including traditional and modern propagation techniques were reviewed. Nutrition-related health benefits derived from cocoa consumption were listed and widely reviewed. The specific action of cocoa antioxidants was compared to those of teas and wines. Effects of adding milk to chocolate and chocolate drinks versus bioavailability of cocoa polyphenols were discussed. Finally, flavor, sensory, microbiological, and toxicological aspects of cocoa consumption were presented.     

Alteration in hydrogen absorption by and hydrogen permeation through a high-strength low-alloy steel due to plasma source ion implantation of nitrogen

Plasma source ion implantation of nitrogen on a high-strength steel substrate carried out at relatively low temperatures produced no discernible nitrides. The hardness increase caused by these treatments was discernible. There was indirect evidence of nitrogen in solid solution. The plasma treatments produced changes in the hydrogen permeation through the substrate as a result of alteration in the subsurface hydrogen solubility as well as the hydrogen diffusivity. The alteration in hydrogen permeation behavior depended on the time and temperature of plasma treatment.     

Electrochemical response of amorphous and devitrified Al‐Ni‐La‐X (X = Ag,Cu) alloys

The electrochemical response of melt‐spun Al‐Ni‐La alloys with partial substitution of Ni after different stages of devitrification was studied. The base alloy was found to have the best corrosion resistance. It was observed that primary crystallization caused minimal deterioration in the corrosion resistance of the base alloy as compared to its amorphous state. The substitute alloys had different corrosion resistance dependent on the substituting element with the Ag containing alloy having the least resistance. This could be attributed to the operation of local galvanic cells, enhanced by chemical heterogeneities in the alloys. Secondary crystallization caused a reduction in the corrosion resistance of all the alloys due to the creation of intermetallic phases that increased the galvanic activity.     

Chaperone-mediated reduction of RepA dimerization is associated with RepA conformational change

RepA, the initiator protein of plasmid P1, binds to multiple sites (iterons) in the origin. The binding normally requires participation of chaperones, DnaJ, DnaK and GrpE. When purified, RepA appears dimeric and is inactive in iteron binding. On reaction with chaperones, a species active in iteron binding is formed and found to be monomeric. To test whether the chaperones can reduce dimerization, RepA was used to replace the dimerization domain of the lambda repressor. The hybrid protein repressed the lambda operator efficiently, indicating that RepA can dimerize in vivo. A further increase in repressor activity was seen in dnaJ mutant cells. These results are consistent with a chaperone-mediated reduction of RepA dimerization. We also found that RepA mutants defective in dimerization still depend on DnaJ for iteron binding. Conversely, RepA mutants that no longer require chaperones for iteron binding remain dimerization proficient. These results indicate that the chaperone dependence of RepA activity is not solely owing to RepA dimerization. Our results are most simply explained by a chaperone-mediated conformational change in RepA protomer that activates iteron binding. This conformational change also results in reduced RepA dimerization.     

The effects of cold working on sensitization and intergranular corrosion behavior of AISI 304 stainless steel

The effects of prior cold rolling of up to an 80 pct reduction in thickness on the sensitization-desensitization behavior of Type AISI 304 stainless steel and its susceptibility to intergranular corrosion have been studied by electrochemical potentiokinetic reactivation (EPR) and Strauss-test methods. The results indicate that the prior deformation accelerated the sensitization as compared to the undeformed stainless steel. The deformed Type 304 stainless steel experienced desensitization at higher temperatures and times, and it was found to be enhanced by increased cold deformation. This could be attributed to the increased long-range chromium diffusion, possibly brought on by increasing pipe diffusion and vacancies. The role of the deformation-induced martensite (DIM) and texture, introduced by uniaxial cold rolling, on the sensitization-desensitization kinetics has also been discussed. This study could not reveal any systematic relationship between texture and the degree of sensitization (DOS) obtained. The effect of DIM on DOS seems to be pronounced at 500 °C when the steel retained significant amounts of DIM; however, the retained DIM is insignificant at higher sensitization times and temperatures.     

Low Temperature Sensitization on the Orthogonal Surfaces of Prior Deformed AISI 304LN and Aged at 673 K to 873 K (400 °C to 600 °C)

This study investigates the sensitization behavior of AISI 304LN deformed previously by cold rolling (CR) to 5 pct to 25 pct reduction in thickness and aged at 673 K to 873 K (400 °C to 600 °C). The emphasis was on revealing the degree of sensitization (DOS) resulting from low-temperature sensitization (LTS) on the orthogonal surfaces and correlation thereof with the changes in various metallurgical properties caused by cold rolling. It was found that the DOS differs among the orthogonal surfaces such as the rolling surface (RS), transverse surface (TS), and cross transverse surface (CTS). RS showed lower DOS compared with CTS and TS. The differences in the DOS were attributed to the combined effect of deformation-induced martensite (DIM), grain size, and slip band formation. A deformation of 5 pct was critical to the susceptibility of AISI 304LN to intergranular (IGC) and transgranular corrosion (TGC). The sensitization kinetics was slow or saturated leading to desensitization beyond 5pct deformations at 773 K (500 °C) and 873 K (600 °C). It was, however, uniformly accelerated over 5 to 25 pct deformation when aged at 673 K (400 °C).     

Study of Giant Magneto-Impedance Behavior in Co-Fe Based Amorphous/Nanocrystalline Materials

Giant magneto-impedance (GMI) behavior have been studied in melt spun Co_71-XFe_XCr₇Si₈B₁₄ (X = 0, 2, 3.2, 4, 6, 8, and 12 at%) alloys. The addition of Fe in the system changed the saturation magnetostriction constant from negative to positive values. The GMI property was measured with a driving current of 5 mA and 4 MHz frequency using a spectrum analyzer. The GMI ratio increased with the increase of the applied dc field and became maximum at a field H_k known as the anisotropy field of the materials. The maximum of GMI ratio (GMI_max) depended on the Fe content and was maximum (12%) for Fe = 4 at% for the alloys in the as-melt spun state. Substantial increase of GMI_max to 66% for Fe = 4 at% was observed after annealing the sample at 673 K.     

Influence of quench rates on the properties of rapidly solidified FeNbCuSiB alloy

FeNbCuSiB based materials were produced in the form of ribbons by rapid solidification techniques. The crystallization, magnetic, mechanical and corrosion behaviour were studied for the prepared materials as a function of quenching rate from liquid to the solid state. Higher quench rates produced a more amorphous structure exhibiting superior soft magnetic properties with improved corrosion resistance.     

Passivity breakdown due to discontinuous precipitation during ageing of 21Cr-10Mn-5Ni stainless steel

Discontinuous precipitation in a 21Cr-10Mn-5Ni steel was found to result in breakdown of passivity when tested in a 0.5 m H₂SO₄ + 0.01 m KSCN solution. The electrochemical response was similar to that due to sensitization of conventional stainless steels. The ageing time and temperature affected the resistance of the passive film, with lower ageing temperatures being more severe in terms of passivity breakdown. The effect of interlamellar spacing on the chromium depletion, the effect of volume diffusion on the healing of the matrix, and the solubility product reaction for precipitation, were considered to explain the observed different strengths of passive films formed on specimens aged at different temperatures and times. The observance of good corrosion protection in spite of the presence of profuse precipitates was in contrast to the effect of grain-boundary carbide proliferation on the corrosion resistance of conventional stainless steels.