Norou Diawara

Polycyclic aromatic hydrocarbon-induced oxidative stress and lipid peroxidation in relation to immunological alteration

Objectives We evaluated the association between exposure to polycyclic aromatic hydrocarbons (PAHs) and immunological measurements using blood samples from coke oven workers exposed to high and low PAH levels. Methods A population-based cross-sectional study was conducted from 2008–2009 with coke oven workers and steel-rolling workers as the exposed and control groups, respectively. Questionnaires on basic demographic information were administered. Personal breathing zone and urine samples were collected to quantify personal PAH intake and biological response doses. Immunological and cytokine parameters in serum were analysed. Urinary malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) were analysed to determine oxidative stress induced by PAHs in relation to altered humoural immunological status. Results Mean levels of serum immunoglobulin A (IgA) and TNF-α were significantly increased in coke oven workers compared to steel-rolling workers who had no or minimal PAH exposure (p=0.0033 and p<0.0001, respectively). There were no significant differences in mean levels of IL-4 and IL-10 between coke oven workers and steel-rolling workers. Moderate activation of lipid peroxidation and oxidative damage as determined by plasma MDA and 8-OHdG levels were detected simultaneously with significant alterations in IgA and IgE levels. Multiple regression analyses demonstrated that PAHs with high molecular weights >252 (dibenzo(a,h)anthracene, benzo(a)pyrene, benzo(a)anthracene and/or indeno(1,2,3-cd)pyrene) correlated with IgA and IgE levels. Conclusions This study showed that coke oven workers with chronic exposure to PAHs may develop immunological alteration. Oxidative stress and lipid peroxidation induced by PAHs may partly explain the alteration in immunological parameters.

Biomonitoring of polycyclic aromatic hydrocarbons from coke oven emissions and reproductive toxicity in nonsmoking workers.

The objective of the cross-sectional study was to assess whether exposure to polycyclic aromatic hydrocarbons (PAHs) from coke oven emissions contributed to alteration of semen quality and sperm DNA integrity in nonsmoking workers. Nonsmoking coke oven workers from a steel plant in Taiwan served as the exposure groups (topside-oven workers for the high exposure group and side-oven workers for the low exposure group), and administrators and security personnel in the plant served as the control. An exposure assessment was conducted to determine both particulate and gaseous phase of PAH levels and urinary 1-hydroxypyrene (1-OHP) levels. Semen quality was analyzed according to WHO guidelines. DNA fragmentation and bulky DNA adducts were measured to assess sperm DNA integrity. There was no significant difference in sperm concentrations, vitality, and DNA fragmentation between the exposed group and the control. The high exposure group experienced significantly lower percentages of normal morphology as compared with the control (p=0.0001). Bulky DNA adducts were detected in the exposed group that were significant higher than the control (p=0.04). Exposure to PAHs from coke-oven emissions could contribute to increased levels of bulky DNA adducts in sperm.

Factors affecting website reconstruction from the web infrastructure

When a website is suddenly lost without a backup, it maybe reconstituted by probing web archives and search engine caches for missing content. In this paper we describe an experiment where we crawled and reconstructed 300 randomly selected websites on a weekly basis for 14 weeks. The reconstructions were performed using our web-repository crawler named Warrick which recovers missing resources from the Web Infrastructure (WI), the collective preservation effort of web archives and search engine caches. We examine several characteristics of the websites over time including birth rate, decay and age of resources. We evaluate the reconstructions when compared to the crawled sites and develop a statistical model for predicting reconstruction success from the WI. On average, we were able to recover 61% of each websites resources. We found that Googles PageRank, number of hops and resource age were the three most significant factors in determining if a resource would be recovered from the WI.

A LASSO Chart for Monitoring the Covariance Matrix

Abstract Multivariate control charts are essential tools in multivariate statistical process control. In real applications, when a multivariate process shifts, it occurs in either location or scale. Several methods have been proposed recently to monitor the covariance matrix. Most of these methods use rational subgroups and are used to detect large shifts. In this paper, we propose a new accumulative method, based on penalized likelihood estimators, that uses individual observations and is useful to detect small and persistent shifts in a process when sparsity is present.

Role of low exposure to metals as male reproductive toxicants.

The objective of the study was to examine the associations between environmentally relevant low metal concentrations and semen quality parameters in men. The concentrations of zinc (Zn), copper (Cu), cadmium (Cd), arsenic (As), selenium (Se), and lead (Pb) in the seminal plasma and urine were measured from 196 male human subjects in Taiwan. Urinary Cd concentrations were negatively associated with sperm viability (p = 0.006). Seminal plasma Cu concentrations of the normal group (≥ 15 × 106/ml) were significantly lower than those of the abnormal group (p = 0.023). However, the linear regression analysis showed a weak association between Cu concentration and sperm concentration, along with other semen parameters. No significant relationship between other metals (As, Pb, Zn, and Se) and semen quality was observed.

A Multivariate Gamma Distribution and its Characterizations

SYNOPTIC ABSTRACT In this paper, we proffer a new multivariate gamma distribution with potential applications in survival and reliability modeling. The multivariate distribution is not necessarily restricted to those with gamma marginal distributions. We provide and characterize a generalized location scale family of multivariate gamma distributions. This family possesses three-parameter gamma marginals (in most cases) and it contains absolutely continuous classes, as well as, the Marshall Olkin type of distributions with a positive probability mass on a set of measure zero. Maximum likelihood estimators are developed in the bivariate case.

Repeated measurements for assessment of urinary 2-naphthol levels in individuals exposed to polycyclic aromatic hydrocarbons.

A repeated measurement cohort study was conducted to determine whether 2-napthol can be a suitable biomarker for evaluating the magnitude of exposure to PAHs from coke oven emissions. Time-course patterns of urinary 2-naphthol levels in coke-oven workers were examined. Also, the correlation between urinary 2-naphthol levels and PAHs from personal breathing zone samples was analyzed while examining and adjusting possible confounding factors, such as smoking alcohol consumption, and age of human subjects. A total of 8 spot urine samples were collected from each high-exposure group (topside-oven workers, n = 17) and low-exposure group (side-oven workers, n = 25) during the whole working cycle, which consists of six consecutive working days followed by 2 days off. Personal breathing zone samples were collected to quantify PAH intake. A questionnaire was distributed and collected from each worker for assessment of demographic parameters. Our results confirmed that the topside-oven area contained significantly higher PAH levels than the side-oven area. Urinary 2-naphthol levels correlated with the levels of PAH species, including pyrene, benzo[k]fluoranthene, benezo[g,h,i]pyrene, naphthalene, phenanthrene, anthracene, indeno[1,2,3-cd]pyrene, benzo[k]fluoranthene, and total PAHs. During the working cycle, urinary 2-naphthol levels remained stable at around 46–97 ng/mg creatinine during the working days and dramatically increased during the off days. After stratification of data based on smoking status, smokers had significantly higher urinary 2-naphthol levels than non-smokers, and 2-naphthol levels positively correlated with smoking status. Coke-oven emissions are a source of exposure to naphthalene. Also, smoking is a significant source of exposure to naphthalene and served as a confounder factor. Due to its abundance, positive association with total PAHs and certain carcinogenic PAH compounds, and slower elimination kinetics, urinary 2-naphthol may have the potential to serve as a biomarker for PAH exposure, when smoking status is carefully adjusted.

Testing a Novel 3D Printed Radiographic Imaging Device for Use in Forensic Odontology

There are specific challenges related to forensic dental radiology and difficulties in aligning X‐ray equipment to teeth of interest. Researchers used 3D printing to create a new device, the combined holding and aiming device (CHAD), to address the positioning limitations of current dental X‐ray devices. Participants (N = 24) used the CHAD, soft dental wax, and a modified external aiming device (MEAD) to determine device preference, radiographers efficiency, and technique errors. Each participant exposed six X‐rays per device for a total of 432 X‐rays scored. A significant difference was found at the 0.05 level between the three devices (p = 0.0015), with the MEAD having the least amount of total errors and soft dental wax taking the least amount of time. Total errors were highest when participants used soft dental wax—both the MEAD and the CHAD performed best overall. Further research in forensic dental radiology and use of holding devices is needed.

Statistical Pattern Recognition Using Gaussian Copula

Statistical pattern recognition has attracted great interest due to its applicability and to the advances in technology and computing. Significant research has been done in areas such as automatic character recognition, medical diagnostics, and data mining. The classical discrimination rule for pattern recognition assumes normality. However, in real life this assumption is often questionable. In some situations, the pattern vector is a mixture of discrete and continuous random variables. In this article, we use copula densities to model class conditional distribution for pattern recognition with Bayes’ decision rule. These types of densities are useful when the marginal densities of a pattern vector are not normally distributed. Those models are also useful for mixed pattern vectors. We also did simulations to compare the performance of the copula-based classifier with classical normal distribution based model and the independent-assumption-based model.

Morphometric analysis of the association of primary shoulder reconstruction procedures with scapular growth in obstetric brachial plexus paralysis patients

BackgroundObstetric brachial plexus paralysis (OBPP) has been associated with shoulder deformities, scapular growth, and shoulder function impairment. The absence of balanced muscular forces acting on the scapula has been considered responsible for scapula dysplasia and impaired growth as compared with the normal side. Scapula growth impairment may also lead to shoulder and upper extremity dysfunction. This study aims at showing the association of primary nerve reconstruction with the restoration of scapular bone growth potential.MethodsThis is a retrospective review of 73 patients with OBPP who underwent primary shoulder reconstruction. Patients were categorized for assessment and analysis into group A, global paralysis; group B, Erb’s palsy; and group C, Erb’s palsy with C7 root involvement. Scapular posteroanterior and lateral X-rays were obtained in which four scapula dimensions were manually measured. The growth discrepancy depending on the applied treatment was investigated.ResultsThe highest improvement was noted in scapular height in the Erb’s palsy group who underwent simultaneous neurotization of the suprascapular and axillary nerves. The oblique axis was more improved in the Erb’s palsy group while both big and small widths were more improved in the Erb’s palsy with C7 root involvement group in patients who underwent concomitant neurotization of the suprascapular and the axillary nerves. Functional improvement correlated positively with growth improvement in all groups and scapular dimensions.ConclusionScapula growth and shoulder function improvement were higher in patients with Erb’s palsy. Simultaneous axillary and suprascapular nerve neurotization provided the best outcome in both functional and growth restoration.