Metal mining and birth defects : a case-control study in Lubumbashi, Democratic Republic of the Congo

Background Widespread environmental contamination caused by mining of copper and cobalt has led to concerns about the possible association between birth defects and exposure to several toxic metals in southern Katanga, Democratic Republic of the Congo (DRC). We therefore aimed to assess the possible contribution of parental and antenatal exposure to trace metals to the occurrence of visible birth defects among neonates. Methods We did a case-control study between March 1, 2013, and Feb 28, 2015, in Lubumbashi, DRC. We included newborns with visible birth defects (cases) and healthy neonates born in the same maternity ward (controls). Mothers were interviewed about potentially relevant exposures, including their partners' jobs. Various trace metals were measured by inductively coupled plasma mass spectrometry in maternal urine, maternal blood, umbilical cord blood, placental tissue, and surface dust at home. Multivariable logistic regression analyses were done to calculate adjusted odds ratios and their 95% CIs (CI). Findings Our study included 138 neonates with visible birth defects (about 0.1% of the 133 662 births in Lubumbashi during the study period) and 108 control neonates. Potential confounders were similarly distributed between cases and controls. Vitamin consumption during pregnancy was associated with a lower risk of birth defects (adjusted odds ratio 0.2, 95% CI 0.1-0.5). Mothers having paid jobs outside the home (2.8, 1.2-6.9) and fathers having mining-related jobs (5.5, 1.2-25.0) were associated with a higher risk of birth defects. We found no associations for trace metal concentrations in biological samples, except for a doubling of manganese (Mn; 1.7, 1.1-2.7) and zinc (Zn; 1.6, 0.9-2.8) in cord blood. In a separate model including placentas, a doubling of Mn at the fetal side of the placenta was associated with an increased risk of birth defects (3.3, 1.2-8.0), as was a doubling of cord blood Zn (5.3, 1.6-16.6). Interpretation To our knowledge, this is the first study of the effects of mining-related pollution on newborns in sub-Saharan Africa. Paternal occupational mining exposure was the factor most strongly associated with birth defects. Because neither Mn nor Zn are mined in Lubumbashi, the mechanism of the association between their increased prenatal concentrations and birth defects is unclear

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Vibro-acoustic simulation of damped orthotropic plates with the wave based method

The wave based method was developed as an efficient methodology for the steady state simulation of vibro-acoustic systems. So far this method could only be used to predict the behaviour of simple panels made out of isotropic materials. With the current rise in importance of lightweight composite panels, there is increasing interest in the efficient simulation of panels with direction dependent properties and more complex damping behaviour. To address this need, in this paper, the application range of the wave-based method is expanded in two directions. In a first step the isotropic material model is extended towards an orthotropic one. Second, a versatile damping model, based on the Augmented Hooke’s Law, is integrated into the methodology. Next, the method is applied to three cases. The first one consists of a rectangular composite panel that is excited by a distributed load. In the second case, a vibro-acoustic model is studied by coupling the panel to an acoustic cavity with a simple geometry. Lastly, a model is made of an existing vibro-acoustic test setup on which the composite panel is mounted. Results are compared to a FEM reference model.status: publishe

Coupling loss factor calculation through Lorentzian-weighted frequency averaging of the direct field dynamic stiffness

Coupling loss factors (CLFs) between components of a structure play an important role in high frequency simulation techniques, such as the Statistical Energy Analysis and hybrid deterministic/statistical approaches, to describe how energy is transferred between the components. They are usually obtained from experiments or from analytical models, based on a modal or wave formulation. However, when the connections between components become more complex, deterministic methods such as the Finite Element Method (FEM) or the Boundary Element Method (BEM) are used. By using the diffuse field reciprocity relation, CLFs can be expressed in terms of the direct field dynamic stiffness matrices. Assuming equivalence between the ensemble and frequency average, this direct field dynamic stiffness can be calculated through frequency averaging of the dynamic stiffness at the junction. The presented method proposes the use of the Lorentzian function as weighting function for the frequency averaging procedure. By applying the complex residue theorem, the Lorentzian weighted frequency integral can be calculated by a single evaluation of the dynamic stiffness at a complex frequency. This method allows for great flexibility since the CLFs can be computed by simple manipulation of matrices from a FEM model that is evaluated at a complex frequency instead of a real one. The introduction of an imaginary part to the evaluation frequency can also be interpreted as the addition of artificial damping to the system. Since the damped waves require a smaller number of elements to capture its behaviour, this opens up the possibility of coarsening the mesh to further improve the computational efficiency. The developed approach is applied to a number of cases and CLF results are compared to those of classical analytical models. The tuning of the width of the Lorentzian function and mesh coarsening are also investigated.status: publishe

Een necrotiserende wonde na sectio ..

A 23-year-old female developed a necrotising wound after a caesarean section. In this case we were however confronted with an abrupt deterioration of the clinical evolution despite a broad-spectrum antibiotic therapy. After the diagnosis of pyoderma gangrenosum and the initiation of a ciclosporine therapy, a quick recovery did fortunately occur.status: publishe

Closure of mesenteric defects is associated with a higher incidence of small bowel obstruction due to adhesions after laparoscopic antecolic Roux-en-y gastric bypass: A retrospective cohort study

INTRODUCTION: Small bowel obstruction (SBO) is a frequent complication after laparoscopic Roux-en-y gastric bypass (LRYGB). OBJECTIVES: We wanted to evaluate the effect of closure of the mesenteric defects on the incidence of SBO and postoperative complications after LRYGB. Furthermore, we wanted to identify possible risk factors for SBO. METHODS: This study was a retrospective cohort study of 1364 patients who underwent a LRYGB between July 2003 and October 2015. Cohort 1 contained 724 patients in whom mesenteric defects were not closed. Cohort 2 contained 640 patients in whom mesenteric defects were closed. Main outcome parameters were the incidence of SBO and postoperative complications as well as potential risk factors for SBO. RESULTS: Closure of the mesenteric defects was associated with a reduction in the incidence of SBO due to internal herniation (4.8% vs. 5.5, p = 0.02) but resulted in a higher incidence of SBO due to postoperative adhesions (4.8% vs. 1.7%, p = 0.004). Multivariate analysis identified smoking as a risk factor for SBO (p = 0.0187). We observed a higher incidence of late postoperative pain in cohort 2 (5.3% vs. 2.1%, p = 0.007). CONCLUSION: Although closure of the mesenteric defects is associated with a lower incidence of SBO due to internal herniation, this effect is countered by a higher incidence of SBO due to postoperative adhesions. Smoking is an independent risk factor for SBO after LRYGB. Closure of the mesenteric defects is associated with a higher incidence of late postoperative pain.status: publishe

Laparoscopic parenchymal preserving hepatic resections in semiprone position for tumors located in the posterosuperior segments

All patients who underwent laparoscopic liver resections in the posterosuperior segments (LPSS) at our center were positioned in semiprone since August 2011. The aims of this study were to assess differences in perioperative outcomes between laparoscopic left lateral sectionectomies (LLLS) performed in supine position and LPSS in semiprone position.status: publishe