Hemodialysis does not impair ventricular functions over 2 years

We aimed to evaluate the long-term effect of hemodialysis (HD) treatment on left and right ventricular (LV and RV) functions in patients with end-stage renal disease. The study population consisted of 22 patients with newly diagnosed end-stage renal disease. Before an arteriovenous fistula was surgically created for HD, the patients were evaluated by echocardiography for systolic and diastolic functions. After the first HD session (mean 24.22 ± 2.14 months), the second echocardiographic evaluations were performed. Left ventricular and RV functions before and after long-term HD treatment were compared. The mean age was 55 ± 13 years and 10 (45%) of the patients were female. After long-term HD treatment, the isovolumic relaxation time was significantly decreased; however, the peak early (E) and late (A) diastolic mitral inflow velocities, E/A ratio, and deceleration time of E wave were not significantly different from the baseline measurements. Also, there was no significantly change in the early diastolic velocity (Ea) of the lateral mitral anulus and the E/Ea ratio. Pulmonary vein peak diastolic velocity, peak atrial reversal velocity, and peak atrial reversal velocity duration remained almost unchanged even though the pulmonary vein peak systolic velocity and the pulmonary vein peak systolic velocity/pulmonary vein peak diastolic velocity ratio were significantly lower after long-term HD treatment. In addition, LV systolic functions, LV diameters, LV mass index, left atrium size, and RV diastolic functions were not statistically different after long-term HD treatment. The myocardium is exposed to hemodynamic, metabolic, and neuro-humoral abnormalities during HD treatment; however, the long-term effects of HD on ventricular functions are not clearly known. The present study showed that the long-term effects of HD on LV and RV functions were insignificant in patients with end-stage renal disease. We have demonstrated that the LV and RV functions did not change significantly after long-term HD treatment. We suggest that this result may be due to regulated blood pressure levels of the patients, treatment of anemia and other metabolic disorders during the HD period and the prevention of weight gain and hypervolemia.     

Recovery of zinc and manganese from alkaline and zinc-carbon spent batteries

This paper concerns the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. The metals were dissolved by a reductive-acid leaching with sulphuric acid in the presence of oxalic acid as reductant. Leaching tests were realised according to a full factorial design, then simple regression equations for Mn, Zn and Fe extraction were determined from the experimental data as a function of pulp density, sulphuric acid concentration, temperature and oxalic acid concentration. The main effects and interactions were investigated by the analysis of variance (ANOVA). This analysis evidenced the best operating conditions of the reductive acid leaching: 70% of manganese and 100% of zinc were extracted after 5 h, at 80 °C with 20% of pulp density, 1.8 M sulphuric acid concentration and 59.4 g L⁻¹ of oxalic acid. Both manganese and zinc extraction yields higher than 96% were obtained by using two sequential leaching steps.     

Improvement of Bi<Subscript>2</Subscript>Sr<Subscript>2</Subscript>Co<Subscript>2</Subscript>O<Subscript>y</Subscript> thermoelectric performances by Na doping

Bi₂Sr_2-xNa_xCo₂O_y thermoelectric materials with x = 0, 0.025, 0.05, 0.075, 0.10, 0.125, and 0.15 have been prepared by the classical solid state reaction. Microstructure has shown an important grain growth when Na is added, leading to very high bulk densities confirmed through density measurements. These modifications have produced a drastic decrease of electrical resistivity without significant modification of Seebeck coefficient. As a consequence, Power Factor has been increased in all Na-doped samples, reaching the maximum value (0.21 mW/K².m at 650 °C) for 0.075 Na samples, which is fairly close to the reported for single crystals.     

Comparison of responses to Ovsynch between Holstein-Friesian and Swedish Red cows

The Ovsynch protocol was designed to synchronize ovulation, thereby allowing timed artificial insemination (TAI) of all cows without detection of estrus. However, the effectiveness of Ovsynch in different breeds of dairy cows has not been previously compared. The aim of this study was to compare the response to Ovsynch in cycling lactating Holstein-Friesian (HF) and Swedish Red (SR) dairy cows. A total of 495 cyclic cows (n = 347 HF, n = 148 SR) were housed together and treated with Ovsynch (GnRH - 7 d - PGF_2α - 56 h - GnRH - 16 to 18 h - TAI). Ovulatory responses, synchronization rate, maximal follicle size at the time of AI, and percentage of pregnant cows per AI (P/AI at 31 and 62 d after AI) were compared between breeds. Ultrasonography was performed during Ovsynch at first GnRH, PGF_2α, at time of AI, and 7 d after AI. Ovulatory response and synchronization rate were similar in HF versus SR cows (60.2 vs. 62.2%; 88.4 vs. 88.5%, respectively). Cows that ovulated to the first GnRH of Ovsynch had smaller follicle size at AI (15.9 ± 0.1 vs. 16.4 ± 0.2 mm). Maximal follicle size at AI was greater for HF (16.4 ± 2.2 mm) than SR (15.5 ± 2.3 mm) cows. The P/AI was greater for SR than HF cows at the 62-d pregnancy diagnosis (56.1 vs. 46.1%). In addition, pregnancy loss between 31 and 62 d of pregnancy was greater in HF (10.1%) than SR (3.5%) cows. Fertility was less in HF cows during the hot season (57.7 in cold vs. 38.1% in the hot season), whereas such a decrease was not observed in SR (60.0 in cold vs. 53.5% in the hot season) cows. Thus, although the GnRH treatments of Ovsynch were equally effective in SR and HF cows, pregnancy outcomes (P/AI at d 62 and pregnancy survival) were greater in SR than HF cows, and P/AI in SR cows was not compromised during the hot season as was found for HF cows.     

Effects of presynchronization with gonadotropin-releasing hormone-prostaglandin F2α or progesterone before Ovsynch in noncyclic dairy cows

The aim of this study was to evaluate the efficiency of presynchronization with GnRH and PGF_2α or with progesterone on overall Ovsynch (OVS) outcomes in noncyclic dairy cows. Cows were scanned 7 d apart with ultrasonography to determine cyclicity. Noncyclic cows (n = 281; no corpus luteum on ovaries at both examinations) were randomly divided into 3 groups. In the GP group (n = 108), the cows received GnRH and PGF_2α (PGF) administrations 7 d apart, and OVS was started 11 d after PGF (GnRH-7 d-PGF-11 d-OVS). In the P4 group (n = 90), the cows were treated for 7 d with an intravaginal progesterone (P4) implant (PRID), and then OVS was started 11 d after removal of the implant (7 d PRID-11 d-OVS). The control group (CON, n = 83) did not receive any presynchronization, and OVS was started at the same time as in the other groups (18 d-OVS). The percentage of cows that became cyclic at the beginning of OVS was lower in the CON group (38.6%; 32/83) than in the presynchronization groups (66.7%, 72/108 in GP; 71.1%, 64/90 in P4). The response to the first GnRH of OVS did not differ among groups (63.9%, 53/83 in CON; 67.6%, 73/108 in GP; 63.3%; 57/90 in P4), and synchronization rates were similar among the groups (74–82%). The cows that responded to presynchronization treatments (GP or P4) had higher pregnancy per artificial insemination (P/AI) than did nonresponding cows. Pregnancy per AI at 31 d did not differ between groups (30.1%, 25/83 in CON; 43.5%, 47/108 in GP; and 35.6%, 32/90 in P4). However, CON cows (24.1%, 20/83) had lower P/AI at 62 d than GP cows (41.7%, 45/108). Embryonic loss was higher in CON (20%, 5/25) compared with the P4 group (3%, 1/32). The administration of GnRH followed by PGF or exogenous progesterone (PRID) similarly increased the percentage of cows that became cyclic before Ovsynch in noncyclic cows, but fertility did not improve. However, the cows that responded to presynchronization had higher fertility rates than the nonresponding cows.     

Effects of Surface Roughness on the Performance of Tangential Inlet Cyclone Separators

This study is carried out to investigate the effects of surface roughness on the flow field and cyclone performance. The flow inside the cyclone separator is modeled as a three-dimensional turbulent continuous gas flow with solid particles as a discrete phase. The continuous gas flow is predicted by solving the governing equations by using the Reynolds Stress turbulence model, and the modeling of the particle motions is based on a Lagrangian approach. The results of the numerical simulations are compared with experimental data as well as with the results of mathematical models. Analysis of computed results shows that increase of relative roughness due to corrosion, wear, or accumulation of particles on the inner walls considerably influences the tangential velocity, cyclone separation efficiency, and cyclone pressure drop especially for high inlet velocities. Decreases in cyclone collection efficiency and pressure drop with the increase in surface roughness are found to be more pronounced for high values of relative roughness.     

Steady-state and dynamic modeling of indirect partial oxidation of methane in a wall-coated microchannel

Steady and dynamic characteristics of catalytic indirect partial oxidation (combined total oxidation and steam reforming) of methane to hydrogen in a wall-coated microchannel are investigated using computational techniques. Steady-state behavior is initially modeled using a two-dimensional axisymmetrical wall-coated reactor model. Considering the small channel diameter, adiabatic operation and negligible transport resistances, response of the microchannel is also investigated using a one-dimensional pseudohomogeneous tubular reactor model. Simulations of the microchannel are carried out using both models for different feed conditions ranging between 1.89 and 2.24 for CH₄/O₂ and 1.17–2.34 for H₂O/CH₄. Outcomes from both models are found to be close, allowing the use of the low-cost one-dimensional model in dynamic simulations. Analysis of transients during the system start-up indicate that steady state is reached between 100 and 120 s depending on the feed composition. Product temperature and flow rates obtained from steady-state and dynamic simulations are found to be close with some differences arising from the finite difference-based numerical method used to solve partial differential equations of the dynamic model. Dynamic responses of the microchannel to several disturbances in the feed are analyzed. The response to a step increase in the inlet oxygen flow rate (decrease of CH₄/O₂ from 2.24 to 1.89) is the elevation of temperature by ca. 100 K, which in turn leads to ca. 33% in hydrogen yield, and the time to reach the new steady state is around 90 s. If the disturbance involves an increase in inlet steam flow, temperature and hydrogen yield decrease in time to a local minimum within 10 s and then gradually increase to the subsequent steady state within 50 s ending up with net reductions of ca. 1.6% and 9%, respectively.     

Efficacy of ampicillin trihydrate or ceftiofur hydrochloride for treatment of metritis and subsequent fertility in dairy cows

Our objectives were to evaluate the efficacy of ampicillin trihydrate for the treatment of metritis in dairy cows compared with ceftiofur hydrochloride and the subsequent effects on pregnancy at first insemination (P/AI). Cows in the first 12 d in milk (DIM) with a uterine discharge score of 5 (watery, reddish or brownish discharge of foul smell) and rectal temperature <39.5°C were diagnosed with metritis based on the fetid discharge, and cows with metritis and rectal temperature ≥39.5°C were diagnosed as having puerperal metritis. Cows with metritis (n = 528) were blocked by parity and type of metritis as fetid discharge or puerperal metritis and, within each block, assigned randomly to receive 11 mg/kg of ampicillin (n = 259) or 2.2 mg/kg of ceftiofur (n = 269) once daily for 5 d. Day of diagnosis of metritis was considered study d 1. A cohort of 268 cows without metritis was selected randomly at 12 DIM. Rectal temperature was measured in cows with metritis on study d 1 to 7, and 12, and vaginal discharge was scored on study d 5, 7, and 12. Metritis cure was characterized by vaginal discharge score of <5 or by vaginal discharge score of <5 and no fever. At 32 ± 3 DIM, vaginal discharge was scored for diagnosis of purulent vaginal discharge. At 39 ± 3 DIM, endometrial cytology was performed. At 53 ± 3 and 67 ± 3 DIM, ovaries were scanned to determine estrous cyclicity. Pregnancy was evaluated after the first AI. Cure of metritis based on vaginal discharge <5 was greater for ampicillin than ceftiofur on d 5 (37.1 vs. 25.2%) and 7 (57.2 vs. 46.3%), but not on d 12 (82.0 vs. 85.0%). Cure of metritis based on vaginal discharge <5 and no fever was greater for ampicillin than for ceftiofur only on d 7 (50.4 vs. 37.9%), but not on d 5 (23.1 vs. 17.6%) and 12 (66.1 vs. 67.4%). Cows with puerperal metritis had reduced cure compared with cows with fetid discharge on d 5 (30.5 vs. 12.8%), 7 (55.2 vs. 33.6%), and 12 (72.0 vs. 61.1%). The proportion of cows with fever on any day after therapy started did not differ between treatments. Fifty-three percent of cows with metritis based on fetid discharge developed fever after initiating antimicrobial therapy. Cows receiving ampicillin had less prevalence of purulent vaginal discharge than those treated with ceftiofur (57.7 vs. 67.8%), but they were both greater than cows without metritis (21.9%). Prevalence of cytological endometritis did not differ between ampicillin and ceftiofur (30.0 vs. 25.4%), but they were both greater than cows without metritis (14.5%). The proportion of estrous cyclic cows (75.0%) and P/AI did not differ among treatments (ampicillin = 28.0% vs. ceftiofur = 28.3% vs. without metritis = 30.5%). Clinical cure was faster for ampicillin than for ceftiofur, but on study d 12 both treatments resulted in similar cure. Clinical cure was less for cows with puerperal metritis than for cows with fetid uterine discharge. Despite differences in uterine health, P/AI at the first insemination did not differ among treatments.     

The effect of various types of poultry pre- and post-rigor meats on emulsification capacity, water-holding capacity and cooking loss

In this study, the relationship between various kinds of poultry meat (quail, partridge, chicken and turkey) on pH, emulsification capacity, water-holding capacity and cooking loss was investigated. The effect of rigor state on pH, emulsification capacity, water-holding capacity and cooking loss was also determined. To investigate these parameters, immediately after slaughter and deboning, meat parts were submitted to both pre- and post-rigor analyses. The results indicated that the emulsification capacity of quail and chicken meat was higher than the values for partridge and turkey meat. Quail meat showed the highest water-holding capacity value in the post-rigor stage. The lowest cooking loss value was found in partridge meat, in both pre- and post-rigor stages. The state of rigor had a significant (P<0.05; P0.01) effect on pH and cooking loss values, respectively.