Role of hydrodynamic factors in controlling the formation and location of unconformity-related uranium deposits: insights from reactive-flow modeling

The role of hydrodynamic factors in controlling the formation and location of unconformity-related uranium (URU) deposits in sedimentary basins during tectonically quiet periods is investigated. A number of reactive-flow modeling experiments at the deposit scale were carried out by assigning different dip angles and directions to a fault and various permeabilities to hydrostratigraphic units). The results show that the fault dip angle and direction, and permeability of the hydrostratigraphic units govern the convection pattern, temperature distribution, and uranium mineralization. Avertical fault results in uranium mineralization at the bottom of the fault within the basement, while a dipping fault leads to precipitation of uraninite below the unconformity either away from or along the plane of the fault, depending on the fault permeability. A more permeable fault causes uraninite precipitates along the fault plane,whereas a less permeable one gives rise to the precipitation of uraninite away from it. No economic ore mineralization can form when either very low or very high permeabilities are assigned to the sandstone or basement suggesting that these units seem to have an optimal window of permeability for the formation of uranium deposits. Physicochemical parameters also exert an additional control in both the location and grade of URU deposits. These results indicate that the difference in size and grade of different URU deposits may result from variation in fluid flow pattern and physicochemical conditions, caused by the change in structural features and hydraulic properties of the stratigraphic units involved

Anemia after kidney transplantation in adult recipients: Prevalence and risk factors

Objective: To evaluate the prevalence of anemia and appraise its risk factors at 6 months after renal transplantation. Materials and Methods: This retrospective study was performed between 2008 and 2010 in 2713 adult kidney transplant recipients to determine the prevalence of posttransplantation anemia. Anemia was defined as hemoglobin concentration of 12 g/dL or less in women and 13 g/dL or less in men. Results: The prevalence of posttransplantation anemia was 52.7, with severe anemia (hemoglobin â¤11 g/dL) detected in 24.4 of patients. Impaired renal function was the only risk factor associated with anemia (odds ratio, 3.6; P = .047). However, severe anemia after kidney transplantation was correlated with female sex (P = .001), renal allograft dysfunction (P = .00), and cytomegalovirus infection (P = .002). Conclusion: The present study demonstrated a quite high prevalence of posttransplantation anemia, in particular associated with impaired renal allograft function. Severe anemia was correlated with female sex, degree of kidney graft dysfunction, and cytomegalovirus infection. © 2011 by Elsevier Inc. All rights reserved

Epidemiological urinalysis of children from kindergartens of Can Gio, Ho Chi Minh City - Vietnam

Background Recent studies on Vietnamese children have shown that kidney diseases are not detected early enough to prevent chronic renal failure. The dipstick test is a simple and useful tool for detecting urinary abnormalities, especially in isolated or remote areas of Vietnam, where children have limited access to health care. Methods This cross-sectional study was conducted in 2011 at seven kindergartens in Can Gio district, Ho Chi Minh City, Vietnam. Two thousand and twelve children, aged 3 to 5, were enrolled. Morning mid-stream urine samples were examined by dipstick. Children with abnormal findings were re-examined with a second dipstick and underwent further investigations. Results Urinalysis was available for 1,032 boys and 980 girls. Mean age was 4.4 ± 0.8 years. Urinary abnormalities were detected in 108 (5.5%) of the subjects. Among them, nitrituria and leucocyturia accounted for more than 50%. Positive fractions of proteinuria, hematuria, nitrituria, leucocyturia, and combined nitrituria and leucocyturia after two dipsticks were 0.1%, 0.1%, 2%, 1% and 0.3%, respectively. Abnormal findings were more common in girls than boys (p < 0.001), and higher in communes with very low (< 50 persons/km2) population density (14.3% vs 4.1%, p < 0.001). A renal ultrasound detected four cases of hydronephrosis and one case of duplication of ureter. Conclusions The prevalence of urinary abnormalities in asymptomatic children in South Vietnam demonstrates the need for hygiene education among parents. Training for dipstick usage for all medical staff at health stations, especially in remote areas and in places with very low population density, is also clearly necessary. Routine urinalysis can be set up if a close control is conducted at locations