Microbial communities in a porphyry copper tailings impoundment and their impact on the geochemical dynamics of the mine waste

The distribution and diversity of acidophilic bacteria of a tailings impoundment at the La Andina copper mine, Chile, was examined. The tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) `oxidation zone' characterized by low-pH (2.5-4), a `neutralization zone' (70-80 to 300-400 cm) and an unaltered `primary zone' below 400 cm. A combined cultivation-dependent and biomolecular approach (terminal restriction enzyme fragment length polymorphism and 16S rRNA clone library analysis) was used to characterize the indigenous prokaryotic communities in the mine tailings. Total cell counts showed that the microbial biomass was greatest in the top 125 cm of the tailings. The largest numbers of bacteria (10(9) g(-1) dry weight of tailings) were found at the oxidation front (the junction between the oxidation and neutralization zones), where sulfide minerals and oxygen were both present. The dominant iron-/sulfur-oxidizing bacteria identified at the oxidation front included bacteria of the genus Leptospirillum (detected by molecular methods), and Gram-positive iron-oxidizing acidophiles related to Sulfobacillus (identified both by molecular and cultivation methods). Acidithiobacillus ferrooxidans was also detected, albeit in relatively small numbers. Heterotrophic acidophiles related to Acidobacterium capsulatum were found by molecular methods, while another Acidobacterium-like bacterium and an Acidiphilium sp. were isolated from oxidation zone samples. A conceptual model was developed, based on microbiological and geochemical data derived from the tailings, to account for the biogeochemical evolution of the Piuquenes tailings impoundment.

Longitudinal analyses of renal lesions due to acute pyelonephritis in children and their impact on renal growth.

PURPOSE: Acute pyelonephritis is a common condition in children, and can lead to renal scarring. The aim of this study was to analyze the progression of renal scarring with time and its impact on renal growth. MATERIALS AND METHODS: A total of 50 children who had renal scarring on dimercapto-succinic acid scan 6 months after acute pyelonephritis underwent a repeat scan 3 years later. Lesion changes were evaluated by 3 blinded observers, and were classified as no change, partial resolution or complete disappearance. Renal size at time of acute pyelonephritis and after 3 years was obtained by ultrasound, and renal growth was assessed comparing z-score for age between the 2 measures. Robust linear regression was used to identify determinants of renal growth. RESULTS: At 6 months after acute pyelonephritis 88 scars were observed in 100 renal units. No change was observed in 27%, partial resolution in 63% and complete disappearance in 9% of lesions. Overall, 72% of lesions improved. Increased number of scars was associated with high grade vesicoureteral reflux (p = 0.02). Multivariate analysis showed that the number of scars was the most important parameter leading to decreased renal growth (CI -1.05 to -0.35, p <0.001), and with 3 or more scars this finding was highly significant on univariate analysis (-1.59, CI -2.10 to -1.09, p <0.0001). CONCLUSIONS: Even 6 months after acute pyelonephritis 72% of dimercapto-succinic acid defects improved, demonstrating that some of the lesions may be not definitive. The number of scars was significantly associated with loss of renal growth at 3 years.

Social and medical vulnerability factors of frequent users at the emergency department: a case-control study

BACKGROUND: Up to 5% of patients presenting to the emergency department (ED) four or more times within a 12 month period represent 21% of total ED visits. In this study we sought to characterize social and medical vulnerability factors of ED frequent users (FUs) and to explore if these factors hold simultaneously. METHODS: We performed a case-control study at Lausanne University Hospital, Switzerland. Patients over 18 years presenting to the ED at least once within the study period (April 2008 toMarch 2009) were included. FUs were defined as patients with four or more ED visits within the previous 12 months. Outcome data were extracted from medical records of the first ED attendance within the study period. Outcomes included basic demographics and social variables, ED admission diagnosis, somatic and psychiatric days hospitalized over 12 months, and having a primary care physician.We calculated the percentage of FUs and non-FUs having at least one social and one medical vulnerability factor. The four chosen social factors included: unemployed and/or dependence on government welfare, institutionalized and/or without fixed residence, either separated, divorced or widowed, and under guardianship. The fourmedical vulnerability factors were: ≥6 somatic days hospitalized, ≥1 psychiatric days hospitalized, ≥5 clinical departments used (all three factors measured over 12 months), and ED admission diagnosis of alcohol and/or drug abuse. Univariate and multivariate logistical regression analyses allowed comparison of two JGIM ABSTRACTS S391 random samples of 354 FUs and 354 non-FUs (statistical power 0.9, alpha 0.05 for all outcomes except gender, country of birth, and insurance type). RESULTS: FUs accounted for 7.7% of ED patients and 24.9% of ED visits. Univariate logistic regression showed that FUs were older (mean age 49.8 vs. 45.2 yrs, p=0.003),more often separated and/or divorced (17.5%vs. 13.9%, p=0.029) or widowed (13.8% vs. 8.8%, p=0.029), and either unemployed or dependent on government welfare (31.3% vs. 13.3%, p<0.001), compared to non-FUs. FUs cumulated more days hospitalized over 12 months (mean number of somatic days per patient 1.0 vs. 0.3, p<0.001; mean number of psychiatric days per patient 0.12 vs. 0.03, p<0.001). The two groups were similar regarding gender distribution (females 51.7% vs. 48.3%). The multivariate linear regression model was based on the six most significant factors identified by univariate analysis The model showed that FUs had more social problems, as they were more likely to be institutionalized or not have a fixed residence (OR 4.62; 95% CI, 1.65 to 12.93), and to be unemployed or dependent on government welfare (OR 2.03; 95% CI, 1.31 to 3.14) compared to non-FUs. FUs were more likely to need medical care, as indicated by involvement of≥5 clinical departments over 12 months (OR 6.2; 95%CI, 3.74 to 10.15), having an ED admission diagnosis of substance abuse (OR 3.23; 95% CI, 1.23 to 8.46) and having a primary care physician (OR 1.70;95%CI, 1.13 to 2.56); however, they were less likely to present with an admission diagnosis of injury (OR 0.64; 95% CI, 0.40 to 1.00) compared to non-FUs. FUs were more likely to combine at least one social with one medical vulnerability factor (38.4% vs. 12.1%, OR 7.74; 95% CI 5.03 to 11.93). CONCLUSIONS: FUs were more likely than non-FUs to have social and medical vulnerability factors and to have multiple factors in combination.

Predictors for the emergence of the 2 multi-nucleoside/nucleotide resistance mutations 69 insertion and Q151M and their impact on clinical outcome in the Swiss HIV cohort study.

The 69 insertion and Q151M mutations are multi-nucleoside/nucleotide resistance mutations (MNR). The prevalence among 4078 antiretroviral therapy (ART)-experienced individuals was <1.3%. Combined ART fully prevented MNR in subtype B infections. Case-control studies were performed to identify risk factors. Control subjects were patients with ≥ 3 thymidine-analogue mutations. The 69 insertion study (27 control subjects, 14 case patients) identified didanosine exposure as a risk (odds ratio, 5.0 per year; P = .019), whereas the Q151M study (which included 44 control subjects and 25 case patients) detected no associations. Following detection, individuals with Q151M tended to have lower suppression rates and higher mortality rates, relative to control subjects. Additional studies are needed to verify these findings in non-subtype B infections.

Value / personality - attitude - behavior hierarchy and its impact on individual performance in the context of market orientation

The purpose of this dissertation is to better understand how individual employees? values and personality traits influence their attitudes toward market orientation; how such attitudes impact their market-oriented behaviors; and how in turn, these behaviors lead to their superior individual performance. To investigate these relationships, an empirical study was conducted in the French speaking part of Switzerland and data were collected from a sample of service firms? employees from diverse departments and hierarchical levels. To a large extent, the results support the hypothesis of a hierarchical chain moving from value / personality to attitude to behavior to individual performance in relation to market orientation. Le sujet de cette thèse de doctorat est de mieux comprendre comment les valeurs et les traits de personnalité des employés influencent leurs attitudes envers l'orientation vers le marché ; comment ces attitudes ont un effet sur les comportements orientés vers le marché de ces employés et enfin, comment ces comportements conduisent à une meilleure performance individuelle. Afin d'étudier ces relations, une enquête a été conduite en Suisse romande et des données ont été collectées auprès d'un échantillon d'employés d'entreprises de service de différents départements et niveaux hiérarchiques. Les résultats sont concordants avec l'hypothèse d'une chaîne causale allant des valeurs / traits de personnalité aux attitudes, aux comportements et finalement à la performance individuelle dans le contexte de l'orientation vers le marché.

Diagnostic and Prognostic Impact of pc-ASPECTS Applied to Perfusion CT in the Basilar Artery International Cooperation Study.

BACKGROUND AND PURPOSE: The posterior circulation Acute Stroke Prognosis Early CT Score (pc-APECTS) applied to CT angiography source images (CTA-SI) predicts the functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS). We assessed the diagnostic and prognostic impact of pc-ASPECTS applied to perfusion CT (CTP) in the BASICS registry population. METHODS: We applied pc-ASPECTS to CTA-SI and cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) parameter maps of BASICS patients with CTA and CTP studies performed. Hypoattenuation on CTA-SI, relative reduction in CBV or CBF, or relative increase in MTT were rated as abnormal. RESULTS: CTA and CTP were available in 27/592 BASICS patients (4.6%). The proportion of patients with any perfusion abnormality was highest for MTT (93%; 95% confidence interval [CI], 76%-99%), compared with 78% (58%-91%) for CTA-SI and CBF, and 46% (27%-67%) for CBV (P < .001). All 3 patients with a CBV pc-ASPECTS < 8 compared to 6/23 patients with a CBV pc-ASPECTS ≥ 8 had died at 1 month (RR 3.8; 95% CI, 1.9-7.6). CONCLUSION: CTP was performed in a minority of the BASICS registry population. Perfusion disturbances in the posterior circulation were most pronounced on MTT parameter maps. CBV pc-ASPECTS < 8 may indicate patients with high case fatality.

Trace element monitoring in the ICU: quality and economic impact of a change in sampling practice.

BACKGROUND & AIMS: Trace elements (TE) are involved in the immune and antioxidant defences which are of particular importance during critical illness. Determining plasma TE levels is costly. The present quality control study aimed at assessing the economic impact of a computer reminded blood sampling versus a risk guided on-demand monitoring of plasma concentrations of selenium, copper, and zinc. METHODS: Retrospective analysis of 2 cohorts of patients admitted during 6 months periods in 2006 and 2009 to the ICU of a University hospital. INCLUSION CRITERIA: to receive intravenous micronutrient supplements and/or to have a TE sampling during ICU stay. The TE samplings were triggered by computerized reminder in 2006 versus guided by nutritionists in 2009. RESULTS: During the 2 periods 636 patients met the inclusion criteria out of 2406 consecutive admissions, representing 29.7% and 24.9% respectively of the periods' admissions. The 2009 patients had higher SAPS2 scores (p = 0.02) and lower BMI compared to 2006 (p = 0.007). The number of laboratory determinations was drastically reduced in 2009, particularly during the first week, despite the higher severity of the cohort, resulting in à 55% cost reduction. CONCLUSIONS: The monitoring of TE concentrations guided by a nutritionist resulted in a reduction of the sampling frequency, and targeting on the sickest high risk patients, requiring a nutritional prescription adaptation. This control leads to cost reduction compared to an automated sampling prescription.