Model for horizontal tube settlers

Tube settlers are classified into two configurations; the essentially horizontal and the steeply inclined. Theoretical and experimental studies were conducted on the basis of an extensive literature review to clarify some of the unsettled questions and a model for both design configurations was proposed, the Fadel Model;The model considers the effect of velocity profile variations ranging from uniform at the tube entrance to fully developed laminar flow profiles at the end of the transition length. Three methods for using the model were established: a computer program, design charts, and an equation;The experimental studies demonstrate the validity of the Fadel Model as a design method for determining particle settling length in circular tube settlers. The effect of sludge accumulation on the performance of the essentially horizontal tubes was studied both theoretically and experimentally;Theoretically, the essentially horizontal tube configuration was found to perform perfectly under conditions of sludge accumulation until the storage depth reached 40% of the tube depth. However, experiments showed that total sludge accumulations of up to 53% tube depth did not cause performance to deteriorate. Accordingly, a maximum allowable storage depth of 40% of the tube diameter is the recommended factor of safety for these horizontal tubes. An inlet and outlet arrangment for the essentially horizontal tubes also was proposed

Dilemma of HCV Infection in Renal Transplant Recipients

Hepatitis C virus, which usually starts during dialysis therapy, is currently the main cause of chronic liver disease in such population. The majority of patients acquired the disease through intravenous drug use or blood transfusion, with some risk factors identified. In this review we are dealing with the effect of renal transplantation on HCV infection and HCV-related complications after renal transplantation. Moreover, we are discussing the therapeutic options of HCV infection before and after renal transplantation, the best immunosuppressive protocol and lastly graft and patient survival in patients who underwent pretransplant management vs. those who were transplanted without treatment

Dexamethasone for the prevention of neonatal respiratory morbidity before elective cesarean section at term

Background: Respiratory distress syndrome (RDS) is the principal cause of early neonatal morbidity and mortality. Objective: The current study aims to evaluate the effect of dexamethasone administration 48 hours before elective cesarean section (CS) at term on neonatal respiratory morbidity. Methods: The current study was a case-control study conducted between June 2015 and November 2015. Women who attended the labor ward in Sohag University Hospital, Egypt, after 37 weeks of gestation for elective CS were approached for participation. The patients received 2 intramuscular doses of 12 mg dexamethasone 12 hours apart in the 48 hours before CS (N=246). The control group included women who did not receive dexamethasone before CS during the same period of the study (N=275). Results: No significant differences were detected between the study and control groups with regard to age, parity or gestational age at delivery. There was a significantly higher number of neonates with RDS and transient tachypnea in the control group compared to the study group (p=0.001). The rate of neonatal admission to the neonatal care unit (NICU) was significantly lower in the study group (p=0.001). Conclusions: Prophylactic dexamethasone administration before elective CS at term significantly reduces neonatal respiratory morbidity and admission to NICU

Adsorption and time dependent fixation of uranium (VI) in synthetic and natural matrices

Disposal of low level radioactive liquid waste to soil is commonly practiced. Therefore, sorption of uranium from aqueous solution and fixation of uranium into soil are processes which are crucial to the attenuation of uranium and protection of groundwater. Exposure of human populations is either by direct water consumption or through crop irrigation and transfer into the food chain. In this study a range of materials, including natural materials (e.g. biochar and the natural zeolites ‘Chabazite and Mordenite’) and the synthetic zeolite ‘Faujasite-X’, were investigated as potential adsorbents for UVI from aqueous solution. A range of experiments were carried out to investigate the efficacy of using these adsorbents to successfully adsorb and fix UVI from aqueous solutions. These included sorption and desorption experiments, quantifying time-dependent fixation of UVI and applying kinetic models of this process and measuring isotopically exchangeable UVI within adsorbent materials when possible. The factors affecting adsorption processes, such as solution pH, initially added UVI concentrations and adsorption contact time, were also investigated. Speciation of U in the solution phase was investigated using the Windermere Humic Aqueous Model (WHAM-VII). Saturation indices of potential solid phases were also configured using known solubility products and the free ion activities predicted from the speciation model, WHAM-VII. Mordenite zeolite showed a poor adsorption affinity for UVI as the solution pH was continuously buffered towards high pH values > 6.5 which favours UVI ion solubilisation as a result of uranyl carbonate complex formation. Uranium (VI) ion adsorption on chabazite at pH 4.7 at 20 oC was found to fit the Freundlich adsorption isotherm but the optimised equation parameters were unique for each contact time of 1, 5, 10, 20 and 30 days. The time-dependent fixation of UVI on chabazite was found to follow an irreversible first-order kinetic equation and an intraparticle diffusion model suggesting slow penetration of chabazite porous structure following initial surface adsorption. Isotopically exchangeable 238UVI (the E-value, UE) adsorbed on chabazite showed that > 65% of initially added UVI remained isotopically exchangeable. Faujasite-X also showed time-dependent fixation of UVI over 35 days of adsorption contact time at pH values 4, 5 and 6. The adsorption kinetics were best described by an irreversible first-order equation and a spherical diffusion model. Desorption trends showed that UVI adsorption into faujasite- X was almost wholly irreversible. Saturation indices calculated from the solubility products and free ion activities of constituent ions showed that the fixation of UVI was not controlled by the precipitation of any solid phase investigated at the studied range of pH values. Bone biochar, a by-product from the production of biofuel and syngas by gasification, was tested as a material for adsorption and fixation of UVI from aqueous solutions. A batch experiment was conducted to study the factors that influence the adsorption and time-dependent fixation on biochar at 20◦C, including pH, initial concentration of UVI and contact time. Uranium (UVI) adsorption was highly dependent on pH. However, it was found that UVI adsorption on biochar was high over a wide range of pH values, from 4.5 to 9.0, and adsorption strength was time-dependent over several days. The experimental data for pH> 7 were most effectively modelled using a Freundlich adsorption isotherm coupled to a reversible first order kinetic equation to describe the time-dependent fixation of UVI within the biochar structure. Desorption experiments showed that UVI was only sparingly desorbable from the biochar with time and isotopic dilution with 233UVI confirmed the low, and time-dependent, lability of adsorbed 238UVI. Below pH 7 the adsorption isotherm trend suggested that precipitation, rather than true adsorption, may occur. Across all pH values (4.5–9) measured saturation indices suggested precipitation was possible: autunite below pH 6.5 and swartzite, liebigite or bayleyite above pH 6.5 Another source of bone biochar with a fraction size of (20x 60 mesh) was investigated as candidate materials for soil remediation. Its ability both to adsorb uranium and to render it non-labile (i.e. chemically inactive) was tested by addition to a wide range of soils recently spiked with 238UVI and incubated under moist conditions. The overall aim was to recommend improved strategies for immobilisation of uranium in soils subject to application of low level radioactive waste solutions. Several measurements were made to assess possible reductions in U availability from biochar addition, including U solubility in 0.01 M Ca(NO3)2, exchangeability in 1 M Mg(NO3)2 solution and isotopic dilution with 233U and 236U. Results showed that 41.3 %, 27.6%, 28.9% and 31.7% were isotopically exchangeable on average for soil amended with 0%, 3%, 5% and 10% loading of biochar, but overall there appeared to be only marginal advantages in adding even large concentrations of biochar to soil. The major factor controlling U solubility, exchangeability and lability was soil pH and the pH value resulting from biochar, rather than the biochar itself. Therefore, while the use of biochar to effectively remove U from water is clear, its role in adsorbing U in the highly buffered soil environment is probably minimal

Dexamethasone for the prevention of neonatal respiratory morbidity before elective cesarean section at term

Background: Respiratory distress syndrome (RDS) is the principal cause of early neonatal morbidity and mortality. Objective: The current study aims to evaluate the effect of dexamethasone administration 48 hours before elective cesarean section (CS) at term on neonatal respiratory morbidity. Methods: The current study was a case-control study conducted between June 2015 and November 2015. Women who attended the labor ward in Sohag University Hospital, Egypt, after 37 weeks of gestation for elective CS were approached for participation. The patients received 2 intramuscular doses of 12 mg dexamethasone 12 hours apart in the 48 hours before CS (N=246). The control group included women who did not receive dexamethasone before CS during the same period of the study (N=275). Results: No significant differences were detected between the study and control groups with regard to age, parity or gestational age at delivery. There was a significantly higher number of neonates with RDS and transient tachypnea in the control group compared to the study group (p=0.001). The rate of neonatal admission to the neonatal care unit (NICU) was significantly lower in the study group (p=0.001). Conclusions: Prophylactic dexamethasone administration before elective CS at term significantly reduces neonatal respiratory morbidity and admission to NICU

Acoustic and videoendoscopic effects of temporary vocal fold augmentation in an office-based setting : a quasi-experimental study

Background: Vocal-fold augmentation is a continuously developing treatment modality for glottic insufficiency. Patients with glottic insufficiency attend the phoniatrics clinics with increasing frequency. Glottic insufficiency may be due to vocal-fold paralysis, paresis, atrophy, sulcus vocalis, scarring, and vocal-fold deficiency after laryngeal surgery. A variety of materials exist for injection augmentation. This follow-up study aimed to assess the short-term as well as long-term outcomes of vocal-fold injection with calcium hydroxyapatite (CaHA) in patients with glottic gap 1-3 mm. Method: This study included 25 patients with glottic insufficiency who underwent injection augmentation with CaHA. All patients were scheduled for voice evaluation using a comprehensive subjective and objective battery of assessments. Assessments were performed before the procedure and after the procedure at 2 months and at 1 year. Results: Perceptual voice quality assessed with the GRBAS scale improved and the results were stable after 1 year. Shimmer and HNR improved continuously through the follow-up sessions, while jitter and f0 showed slight improvement after CaHA injection. Conclusion: Voice improvement after injection of CaHA requires a minimum of 2 months to develop and may last for a long period.Peer reviewe

Developing a Chromatographic 99mTc Generator Based on Mesoporous Alumina for Industrial Radiotracer Applications: A Potential New Generation Sorbent for Using Low-Specific-Activity 99Mo.

The commercial low-pressure column chromatographic 99Mo/99mTc generator represents a reliable source of onsite, ready-to-use 99mTc for industrial applications. These generators use fission-produced 99Mo of high specific activity, posing serious production challenges and raising proliferation concerns. Therefore, many concepts are aimed at using low-specific-activity (LSA) 99Mo. Nonetheless, the main roadblock is the low sorption capacity of the used alumina (Al2O3). This study investigates the feasibility of using commercial alumina incorporated with LSA 99Mo to develop a useful 99Mo/99mTc generator for industrial radiotracer applications. First, the adsorption profiles of some commercial alumina sorbents for LSA 99Mo were tested under different experimental conditions. Then, the potential materials to develop a 99Mo/99mTc generator were selected and evaluated regarding elution yield of 99mTc and purity. Among the sorbents investigated in this study, mesoporous alumina (SA-517747) presented a unique sorption-elution profile. It demonstrated a high equilibrium and dynamic sorption capacity of 148 ± 8 and 108 ± 6 mg Mo/g. Furthermore, 99mTc was eluted with high yield and adequate chemical, radiochemical, and radionuclidic purity. Therefore, this approach provides an efficient and cost-effective way to supply onsite 99mTc for radiotracer applications independent of fission-produced 99Mo technology

Capability of the Invasive Tree Prosopis glandulosa Torr. to Remediate Soil Treated with Sewage Sludge

Sewage sludge improves agricultural soil and plant growth, but there are hazards associated with its use, including high metal(loid) contents. An experimental study was conducted under greenhouse conditions to examine the effects of sewage sludge on growth of the invasive tree Prosopis glandulosa, as well as to determine its phytoremediation capacity. Plants were established and grown for seven months along a gradient of sewage sludge content. Plant traits, soil properties, and plant and soil concentrations of N, P, K, Cd, Pb, Cu, Ni, Zn, Cr, Co, As, and Fe were recorded. The addition of sewage sludge led to a significant decrease in soil pH, and Ni, Co, and As concentrations, as well as an increase in soil organic matter and the concentrations of N, P, Cu, Zn, and Cr. Increasing sewage sludge content in the growth medium raised the total uptake of most metals by P. glandulosa plants due to higher biomass accumulation (taller plants with more leaves) and higher metal concentrations in the plant tissues. P. glandulosa concentrated more Cd, Pb, Cu, Zn, and Fe in its below-ground biomass (BGB) than in its above-ground biomass (AGB). P. glandulosa concentrated Ni, Co, and As in both BGB and AGB. P. glandulosa has potential as a biotool for the phytoremediation of sewage sludges and sewage-amended soils in arid and semi-arid environments, with a potential accumulation capability for As in plant leaves

Sickle Cell Disease (SCD)

Sickle cell anemia (SCA) is a disease that is caused by the formation of an abnormal hemoglobin type, which can bind with other abnormal hemoglobin molecules within the red blood cells (RBCs) to cause rigid distortion of the cell. This distortion prevents the cell from passing through small blood vessels; leading to occlusion of vascular beds, followed by tissue ischemia and infarction. Infarction is frequent all over the body in patients with SCA, leading to the acute pain crisis. Over time, such insults result in medullary bone infarcts and epiphyseal osteonecrosis. In the brain, cognitive impairment and functional neurologic deficits may occur due to white matter and gray matter infarcts. Infarction may also affect the lungs increasing susceptibility to pneumonia. The liver, spleen, and kidney may show infarction as well. Sequestration crisis is an unusual life-threatening complication of SCA, in which a significant amount of blood is sequestered in an organ (usually the spleen), leading to collapse. Lastly, since the RBCs are abnormal, they are destroyed, resulting in a hemolytic anemia. However, the ischemic complications in patients with SCA disease far exceed the anemia in clinical significance