Residue Analysis of Some PAHs in Some Algerian Soil: A Preliminary Environmental Impact Assessment

AbstractPolycyclic Aromatic Hydrocarbons are among the most persistent pollutants in various environmental matrices including soil. Because of their considerable toxicity even at low concentrations, it is essential to detect them at such very low levels (about ng/Kg) and to quantify them with precision and reliability. The objective of the present work is to determine residues of some PAHs in samples of superficial soil collected from a number of sites including the vicinity of an industrial park of a cement factory, rural soil, surrounding this industrial park, cereal grown soil close to the industrial park and also from urban ground in the north west of Algeria. A high resolution gas liquid chromatorgraph, coupled with high resolution mass spectroscopy (HRGC / HRMS) was used to measure PAH residues and their distribution in the soil. Results show that all investigated soil samples are highly contaminated with PAH. The concentration of the PAHs varies between 24, 62704.104 and 1072, 45064. 104 ng/kg. Residues of the potentially carcinogenic PAH benzo [a] pyrene, were also detected in some of the soil samples. Residues detected in the present study vary between 2,189.103 ng/kg and 506, 4848.103 whereas the value of Hazardous Substances Data Bank (HSDB) is approximately 2.103 ng/Kg. The present results indicated that soil samples examined in the present study are highly contaminated with PAHs compounds, posing potential toxicological risk, considering their carcinogenic and/or mutagenic properties

STRESS AND COPING STRATEGIES AMONG UNDERGRADUATE HEALTH PROFESSIONS STUDENTS: A CROSS-SECTIONAL STUDY FROM A UNIVERSITY IN LEBANON

Introduction: Stress, whether real or perceived, is prevalent among young adults (18-24 years), with prevalence increasing. Previous research has identified and defined many coping mechanisms in response to stress among health professions students. Aims: This study aims at measuring perceived stress and exploring both sources of stress and coping strategies in undergraduate health professions students. Materials and Methods: A total of 427 (88.9% response rate) surveys were collected from the various faculties from across health professions faculties at Beirut Arab University (BAU). Surveys consisted of the Brief COPE Inventory (BCI) and the Perceived Stress Scale (PSS) and were distributed via the systematic sampling method. Results: There was no significant difference between perceived stress scores across faculties, with stress levels falling within a moderate stress range. Females (M=22, SD=6) demonstrated higher stress means than males (M=18, SD=6) across faculties. Junior students, except for pharmacy students, were more likely to use both approach-based and avoidance-based stratagems in comparison to their seniors. However, the differences were insignificant. Stress did not seem to decrease with seniority with any significance across all faculties. Coping stratagems were consistent across all years, leaning towards approach-based mechanisms. Conclusion: Moderate stress levels were observed across all health professions faculties at BAU, and stress levels did not seem to attenuate with passing academic years. It is imperative to optimize student support systems on campus, and encourage students to seek help whenever needed

Gemcitabine and treatment of diffuse large B-cell lymphoma in relapsed or refractory elderly patients: A prospective randomized trial in Algeria

Context: Support for non-Hodgkin\u2032s lymphoma (NHL) with large cells that is refractory or relapsed after first-line chemotherapy poses a greater therapeutic problem with bone marrow transplant therapy or when old age is a contra-indication for high-dose chemotherapy, especially among developing countries such as Algeria. Aim: To show that the regimen, including gemcitabine, could be more effective in treating elderly patients with diffuse large B-cell lymphoma (DLBCL) in relapse / refractory, without complete remission, when compared with the ESHAP (etoposide, cisplatine, solumedrol, aracytine) regimen. Materials and Methods: Ninety-six patients in the age group of 60-70 years were volunteers for a prospective randomized single-blind study, carried out for three years. Patients were divided into two groups by the drawing of lots. The first group (GA, n = 48, relapse; n = 27 [56.3%], refractory; n = 21 [43.7%]) received treatment with ESHAP protocol and the second one (GB, n = 48, relapse; n = 28 [58%], refractory; n = 20 [42%]) with GPD (gemcitabine, dexamethasone, cisplatine) protocol. Results: The overall response rates and mean survival at three years were significantly higher among patients subjected to GPD treatment compared with those subjected to ESHAP treatment (63% vs. 55%, P = 0.01 and 20.5% [95% CI 16.5-24.5] vs. 11.8% [8.9-14.6], respectively). Additionally, three-year progression-free and event-free survival rates were 20.5% (16.3-24) and 19.7% (15.9-23.5), respectively, for the GPD regimen and 10.9% (8.2-13.7) and 11.1% (95% CI 8.5-13.7), respectively, for the ESHAP regimen. Moreover, the GPD regimen was associated with improving overall survival (RR=2.02, 95% CI 1.59-2.56; P = 0.000), event-free survival (2.03, 1.64-2.52; P < 0.001) and progression-free survival (1.86, 1.46-2.37; P < 0.001). Conclusion: In cases of contra-indication for high-dose chemotherapy for elderly patients with DLBCL, without complete remission, the Gemcitabine-based therapy protocol represents a more effective and less toxic than that of ESHAP

Simulation of natural ventilation of different configurations of a room equipped with a solar chimney under the city of Ouarzazate (Morocco) climatic conditions

Natural ventilation is considered as an effective way to improve ventilation and thermal comfort and reduce energy consumption in residential buildings. In this sense, natural ventilation is done by a solar chimney. It is used to increase the air flow through the room by converting thermal energy into kinetic energy. In this work, we intend to present the results of a three dimensional numerical simulation by ANSYS software of natural ventilation through a room equipped with a solar chimney in semiarid climatic conditions of Ouarzazate (Morocco). The chimney is modelled by a rectangular channel with two South-East oriented glass faces. The main objective is to investigate effects of room dimensions for a solar chimney with of fixed dimensions. We also investigate effects of air velocity, turbulence of kinetic energy and air-flow rate in each area of room and solar chimney and determine optimal dimensions of solar chimney for each room size

Efficiency of a Pretreatment by Electrocoagulation with Aluminum Electrodes in a Nanofiltration Treatment of Polluted Water

International audienceThe decrease of quality and availability of waters induces the research of hyphenated technologies for improving purification processes. The paper is devoted to the water treatment of a lack which accumulates a diversified pollution arising from a lot of industries. The investigated lack water contained heavy metals, fecal bacteria and high chemical pollution as measured by its chemical oxygen demand (COD). An electrocoagulation was applied as water pretreatment of a nanofiltration process. The electrocoagulation was carried out in a batch experiment with two parallel aluminum plates of 15 cm2. Water analysis showed a decrease of the COD from 60 to 5 mg L-1, depending upon current density, current charge and solution pH. Thanks to electrocoagulation efficiency, the most probable number (MPN) of bacteria decreased from 2500 to 2 MPN/100 mL. This disinfection allowed the performing of a continuous coupling treatment of electrocoagulation and nanofiltration by using a cylindrical aluminum anode and an organic Nanomax50 membrane respectively

Electrochemical treatment of spent tan bath solution for reuse

A spent tanning bath contains high concentration of salts, chromium and protein. The treatment system for removal of chlorides or chromium from this effluent is expensive. In this context this waste has to be reused. Our study focuses on the application of advanced oxidation processes for protein removal present in a tanning bath. To improve the quality of the chromium tanning bath, two electrochemical processes (electrooxidation and peroxi-electrocoagulation process, PEP) are investigated in a batch reactor. The effects of operational parameters such as reactor configuration, current density and electrolysis time on chemical oxygen demand (COD) and protein removal efficiency are examined. Results indicated that under the optimum operating range for process, the COD and protein removal efficiency reached 53 and 100%, respectively. The optimum values are determined for the hybrid process (PEP) under 0.13 A·cm−2 over 2 h. The treated tanning bath is used as a tanning solution in leather processing. The influence of chromium salt dose, pH solution, stirring time and contact time on the leather characteristic is evaluated. The hides tanned after the addition of 0.25% of commercial chromium salt, at pH solution, leaving them stirring for 4 h with a contact time of 2 days, and showed good hydrothermal stability and physical characteristics of leather

Federated Machine Learning

The communication and networking field is hungry for machine learning decision-making solutions to replace the traditional model-driven approaches that proved to be not rich enough for seizing the ever-growing complexity and heterogeneity of the modern systems in the field. Traditional machine learning solutions assume the existence of (cloud-based) central entities that are in charge of processing the data. Nonetheless, the difficulty of accessing private data, together with the high cost of transmitting raw data to the central entity gave rise to a decentralized machine learning approach called Federated Learning. The main idea of federated learning is to perform an on-device collaborative training of a single machine learning model without having to share the raw training data with any third-party entity. Although few survey articles on federated learning already exist in the literature, the motivation of this survey stems from three essential observations. The first one is the lack of a fine-grained multi-level classification of the federated learning literature, where the existing surveys base their classification on only one criterion or aspect. The second observation is that the existing surveys focus only on some common challenges, but disregard other essential aspects such as reliable client selection, resource management and training service pricing. The third observation is the lack of explicit and straightforward directives for researchers to help them design future federated learning solutions that overcome the state-of-the-art research gaps. To address these points, we first provide a comprehensive tutorial on federated learning and its associated concepts, technologies and learning approaches. We then survey and highlight the applications and future directions of federated learning in the domain of communication and networking. Thereafter, we design a three-level classification scheme that first categorizes the federated learning literature based on the high-level challenge that they tackle. Then, we classify each high-level challenge into a set of specific low-level challenges to foster a better understanding of the topic. Finally, we provide, within each low-level challenge, a fine-grained classification based on the technique used to address this particular challenge. For each category of high-level challenges, we provide a set of desirable criteria and future research directions that are aimed to help the research community design innovative and efficient future solutions. To the best of our knowledge, our survey is the most comprehensive in terms of challenges and techniques it covers and the most fine-grained in terms of the multi-level classification scheme it presents.Peer reviewe

Bone microarchitecture characterization based on fractal analysis in spatial frequency domain imaging

International audienceThis paper suggests a new technique for trabecular bone characterization using fractal analysis of X-Ray and MRI texture images for osteoporosis diagnosis. Osteoporosis is a chronic disease characterized by a decrease in bone density that can lead to fracture and disability. In essence, the proposed fractal model makes use of the differential box-counting method (DBCM) to estimate the fractal dimension (FD) after an appropriate image preprocessing stage that ensures a robust estimation process. In this study, we showed that within the frequency domain generated through discrete cosine transform (DCT), only a quarter of DCT coefficients are enough to characterize osteoporotic tissues. The algorithmic complexity of the developed approach is of the order of N8log2N8 where N stands for the size of the image, which, in turn, likely yields important gain in terms of medication cost. We report a successful separation of healthy and pathological cases in term of both P - value (using statistical Wilcoxon rank sum test) and margin difference. A comparative statistical analysis has been performed using a publicly available database that contains a set of MRI and X-Ray texture images of both healthy and osteoporotic bone tissues. The statistical results demonstrated the feasibility and accepted performance level of our fractal model-based diagnosis to discriminate healthy and unhealthy trabecular bone tissues. The developed approach has been implemented on a medical device prototype

Nanofiltration Treatment of Industrial Wastewater Doped with Organic Dye: A Study of Hydrodynamics and Specific Energy

This study was conducted to eliminate the ions and molecules present in the industrial wastewater received by the municipal wastewater treatment plant (WWTP) of Reghaia, which is located east of Algiers, Algeria. The process was developed for two different study matrices: (a) the wastewater from WWTP and (b) wastewater mixed with Brilliant Blue FCF (BBF) dye to show the influence of the strength of the ionic solution on the treatment. The most effective operating parameters were determined by assessing the residence time distribution applied to the reactor flow regime. Energy analysis showed the viability of a nanofiltration membrane, improving the permeate flux. The nanofiltration process consumed 1.94 kWh/m3 to reduce the chemical oxygen demand (COD) of 63.58% and 48.35% for raw wastewater and doped BBF wastewater, respectively. The results demonstrated that nanofiltration performance with a volume dilution ratio of 1/2 showed the reduction of the COD of 87.2% after 15 min for undoped wastewater, whereas the retention rate decreases to 64% with an increase of dilution ratio to 4/5 for the same water matrix. The influence of a pH of 5 has a significant influence on the composition of the wastewater matrix by the reduction of COD of 49.8% and 59.68% for doped wastewater and raw wastewater, respectively. This could be explained by the isolated points of the membrane in the order of 4.5