HAL Portal usj Université Saint-Joseph de Beyrouth-Liban
Not a member yet
1220 research outputs found
Sort by
Source apportionment of oxidative potential of PM2.5 in an East-Mediterranean site
No full textInternational audienceAmong the different air pollutants, PM2.5 can be easily inhaled into the lungs and might cause diverse health effects especially cardiovascular and respiratory diseases. That is why it is important to understand which species contribute the most to the toxicity of these particles. One of the practical indicators recently used for the evaluation of the oxidative capacity of PM as whole is the oxidative potential (OP). In this study, the oxidative potential of PM2.5 was evaluated using dithiothreitol (DTT) and ascorbic acid (AA) assays on samples collected in an urban site under industrial influence in the East Mediterranean: Zouk Mikael region (ZK) in Lebanon. ZK is characterized by the biggest power plant in the country which runs on heavy fuel oil, a high density of population (4,200 inhabitants/km2) along with high road traffic and the use of diesel generators for electricity generation. The mean volume normalized OP-AAv value was 0.67 ± 0.29 nmol.min-1.m-3. On the other hand, the mean OP-DTTv was 0.52 ± 0.32 nmol.min-1.m-3. Different approaches were used to study the relationship between the characterized species (carbonaceous matter, ions, major and trace elements, and organic compounds) or the sources contribution and OP values. Spearman correlations and hierarchical classification after principal components analysis showed that both OP-DTTv and OP-AAv were correlated with species emitted from HFO combustion, diesel generators, crustal dust, road dust and vehicular emissions sources. A multiple linear regression approach was applied to the contribution of the sources obtained by PMF and the OP values. The results showed that the sources that largely contribute to the PM2.5 mass (crustal dust and ammonium sulfate sources) were not the major sources contributing to the values of OP. However, local anthropogenic sources such as biomass burning (33% of OP-AAv and 9% of OP-DTTv), vehicular emissions (20% and 23%), and heavy fuel oil combustion (31% and 46%) contribute the most to the OP-AAv and OP-DTTv, respectively. This study is a first in Lebanon and in the East Mediterranean and the Middle Eastern region presenting results of oxidative potential (OP-AA and OP-DTT). The findings of this study will be of utmost importance to policymakers in order to implement policies to protect health and improve the air quality in the region
Phenolic Compounds Recovery from Blood Orange Peels Using a Novel Green Infrared Technology Ired-Irrad®, and Their Effect on the Inhibition of Aspergillus flavus Proliferation and Aflatoxin B1 Production
No full textInternational audienceThe intensification of total phenolic compound (TPC) extraction from blood orange peels was optimized using a novel green infrared-assisted extraction technique (IRAE, Ired-Irrad®) and compared to the conventional extraction using a water bath (WB). Response surface methodology (RSM) allowed for the optimization of ethanol concentration (E), time (t), and temperature (T) in terms of extracted TPC and their antiradical activity, for both WB extraction and IRAE. Using WB extraction, the multiple response optimums as obtained after 4 h at 73 °C and using 79% ethanol/water were 1.67 g GAE/100 g for TPC and 59% as DPPH inhibition percentage. IRAE increased the extraction of TPC by 18% using 52% ethanol/water after less than 1 h at 79 °C. This novel technology has the advantage of being easily scalable for industrial usage. HPLC analysis showed that IRAE enhanced the recovery of gallic acid, resveratrol, quercetin, caffeic acid, and hesperidin. IR extracts exhibited high bioactivity by inhibiting the production of Aflatoxin B1 by 98.9%
Smart Insurance Contracts Shielding Pandemic Business Disruption in Developing Countries and Blockchain Solution
No full textInternational audienceAs the Fourth Industrial Revolution gains momentum and involves a plethora of disruptive technology concepts, such as blockchain, they have infiltrated economies that have only experienced a small portion of their scope, consequences, and applications in their different branches. This research aims to examine the potential uses of blockchain technology within the framework of smart contracts in the insurance sector, notably in the event of a pandemic that results in business interruption. Businesses hardly ever take business interruption insurance into account, particularly in a country similar to Lebanon, where natural disasters and pandemics are scarce. Due to the complexity of the task and the numerous requirements for trust in terms of risk consistency, traditional insurance companies are not interested in offering these kinds of insurance contracts. In this current study, a quantitative study was conducted over 213 businesses in various fields and revealed acceptance and socio-demographic differences in the activity sectors of this potentially ground-breaking solution for a developing country that is undergoing a sanitary and economic crisis. As a result, smart contracts and decentralized finance (DeFi) were proposed in the current research as potential solutions to overcome the Lebanese currency devaluation and high insurance costs
Three centers experience with device closure of congenital Gerbode‐type perimembranous ventricular septal defects
No full textInternational audienceAbstractObjectivesWe aim to evaluate our experience with interventional closure of Gerbode-type perimembranous ventricular septal defects (pmVSDs).MethodsWe performed three-center retrospective data review of patients with congenital indirect Gerbode-type pmVSDs treated percutaneously between August 2017 and May 2021. Standard safety and latest follow-up outcomes were assessed.ResultsTen patients (six females) were identified with a median age of 6.8 years (range: 2.5–54) and a median weight of 26.5 kg (range: 12–88). The median left ventricular defect size was 10 mm (range: 3–15.5). On baseline ultrasound, 6 patients had absent subaortic rim , 6 patients had trivial aortic regurgitation, and 3 patients had tear-drop-type (small) aortic cusp prolapse. The tricuspid regurgitation was graded II (n = 5) and III (n = 5). Five Lifetech Konar-Multifunctional occluders, four Amplatzer duct occluders II and one Amplatzer duct occluder I were implanted. The median fluoroscopy time was 10.4 min (range: 4.3–20.2). Pre-existing aortic regurgitations remained identical. One new aortic regurgitation was identified before discharge and remained trivial after 48 months of follow-up. No heart block or tricuspid stenosis was observed on a median follow-up of 17 months (range: 3–48). All patients are symptom-free with complete shunt closure and significant regression or resolution of tricuspid regurgitation.ConclusionsDespite anatomical challenges, interventional closure of congenital indirect Gerbode-type pmVSD appears to be feasible, safe, and most importantly clinically effective using different commercially available devices. Amplatzer duct occluder II and Lifetech Konar-Multifunctional occluder offer interesting specifications to retrogradely target this specific defect with success
Bioproduction of 2-Phenylethanol through Yeast Fermentation on Synthetic Media and on Agro-Industrial Waste and By-Products: A Review
No full textInternational audienceDue to its pleasant rosy scent, the aromatic alcohol 2-phenylethanol (2-PE) has a huge market demand. Since this valuable compound is used in food, cosmetics and pharmaceuticals, consumers and safety regulations tend to prefer natural methods for its production rather than the synthetic ones. Natural 2-PE can be either produced through the extraction of essential oils from various flowers, including roses, hyacinths and jasmine, or through biotechnological routes. In fact, the rarity of natural 2-PE in flowers has led to the inability to satisfy the large market demand and to a high selling price. Hence, there is a need to develop a more efficient, economic, and environmentally friendly biotechnological approach as an alternative to the conventional industrial one. The most promising method is through microbial fermentation, particularly using yeasts. Numerous yeasts have the ability to produce 2-PE using l-Phe as precursor. Some agro-industrial waste and by-products have the particularity of a high nutritional value, making them suitable media for microbial growth, including the production of 2-PE through yeast fermentation. This review summarizes the biotechnological production of 2-PE through the fermentation of different yeasts on synthetic media and on various agro-industrial waste and by-products
Chemical profiles of PM2.5 emitted from various anthropogenic sources of the Eastern Mediterranean: Cooking, wood burning, and diesel generators
No full textInternational audienceThe chemical profiles of PM2.5 emitted from a non-road diesel generator, wood burning and cooking activities including chicken and beef charcoal grilling and general cooking activities were determined. The characterization included the carbonaceous fraction (OC/EC), water-soluble ions, elements, and organic species comprising n-alkanes, polycyclic aromatic hydrocarbons, carboxylic acids, levoglucosan, dioxins, furans, and dioxin-like polychlorinated biphenyls. The main component in the PM2.5 from the different sources was carbonaceous matter with a mass contribution to PM2.5 of 49% for cooking activities, 53% for wood burning, 66% for beef grilling, 72% for chicken grilling, and 74% for diesel generator with different OC/EC concentration ratios. The analysis of organic compounds contents using diagnostic ratios and indexes showed differences between the sources and revealed specific source markers. The water-soluble ions had the highest contribution in the cooking activities profile with 17% of PM2.5 and the least in the chicken grilling profile (1.1%). Additionally, 29 analyzed elements were identified, and their contribution varied with the sources (ranging from 1% to 11% of PM2.5). These findings could be used to differentiate these sources and could assist in the use of source apportionment methods
Towards a Single Currency in Natural Syria Region - A Conceptual Monetary Innovation: A Reflection
No full textInternational audienceThis research paper studies the benefits and the feasibility of a Single Currency in the Natural Syria region. Theeconomic crisis that heavily weighs on the countries of this region makes it primordial to join forces and converge resources, potentials, and opportunities to raise the standard of living. A monetary union with its single currency may hold structural remedies to the woes of this region whose ability to face its economic, political, and internal difficulties depends mainly on the logic of support and cooperation. Based on a conceptual model of a currency basket, taking into consideration specific economic and monetary criteria, this potential union is enhanced by a single currency establishment that must be a feature of economic and political relations between the countries of the region which achieve the supreme interest represented in eliminating cases of fragmentation and disintegration and ensuring a comfortable life for the citizen. Hereby, the implementation of a Single Currency in Natural Syria seems to be a real turning point
Attitude towards Online Shopping during Pandemics: Do Gender, Social Factors and Platform Quality Matter?
No full textInternational audienceBecause of the advancement of electronic commerce, online shopping has emerged, merging commercial and social activities and enhancing the social presence and value of the online environment. To improve the understanding of the changes in the consumer behavior during the COVID-19 pandemic, this study proposes a set of characteristics connected to the social side of online shopping and their influence on client purchasing attitude in addition to the quality of the platforms that are being used (service quality, system quality and information quality). For this matter, a survey of 289 Lebanese people was circulated in 2021 and a quantitative method was used to answer three research questions. Types of goods purchased and frequency of buying on-line were tested to check the presence of any gender differences, in addition to the relationship between the variables studied in the model. According to the research, social presence, social value, and tendency to compare products on different shopping platforms all have a significant correlation with the attitude towards online shopping, where the system quality was the least significant. When it comes to purchasing frequency and product types, the data gathered imply that gender disparities are considerable. This study does not consider the consumer’s living environment or whether there are any age differences between the generations shopping online
Identifying SARS-COV-2 infected patients through canine olfactive detection on axillary sweat samples; study of observed sensitivities and specificities within a group of trained dogs
No full textInternational audienceThere is an increasing need for rapid, reliable, non-invasive, and inexpensive mass testing methods as the global COVID-19 pandemic continues. Detection dogs could be a possible solution to identify individuals infected with SARS-CoV-2. Previous studies have shown that dogs can detect SARS-CoV-2 on sweat samples. This study aims to establish the dogs’ sensitivity (true positive rate) which measures the proportion of people with COVID-19 that are correctly identified, and specificity (true negative rate) which measures the proportion of people without COVID-19 that are correctly identified. Seven search and rescue dogs were tested using a total of 218 axillary sweat samples (62 positive and 156 negative) in olfaction cones following a randomised and double-blind protocol. Sensitivity ranged from 87% to 94%, and specificity ranged from 78% to 92%, with four dogs over 90%. These results were used to calculate the positive predictive value and negative predictive value for each dog for different infection probabilities (how likely it is for an individual to be SARS-CoV-2 positive), ranging from 10–50%. These results were compared with a reference diagnostic tool which has 95% specificity and sensitivity. Negative predictive values for six dogs ranged from ≥98% at 10% infection probability to ≥88% at 50% infection probability compared with the reference tool which ranged from 99% to 95%. Positive predictive values ranged from ≥40% at 10% infection probability to ≥80% at 50% infection probability compared with the reference tool which ranged from 68% to 95%. This study confirms previous results, suggesting that dogs could play an important role in mass-testing situations. Future challenges include optimal training methods and standardisation for large numbers of detection dogs and infrastructure supporting their deployment
Cytotoxicity of V-Prep Versus Phosphoric Acid Etchant on Oral Gingival Fibroblasts
No full textInternational audienceThe most used etchant in dental daily practice is the phosphoric acid (P.A.; 37%). However, acid etchants can induce necrosis on the oral mucosa and cause the ulceration of periodontal tissue when a rubber dam is not used. V-prep is a new practical alternative, and it has satisfactory results. It is used as a preparation before the application of a resin-modified glass ionomer composite (RMGIC) to bond the orthodontic brackets. The aim of this study was to investigate the effect of the V-prep on oral gingival fibroblasts cells by comparing the cell damage and cell viability after the use of V-prep and a conventional phosphoric acid etchant with different application times and concentrations. Therefore, Gingival fibroblasts passage 6 (GFP6) was grown and treated with an acid etchant and V-prep at three different concentrations (1:1, 1:2 and 1:10) for two different application durations (30 s and 1 min). The morphological changes, cell death and cell viability were assessed. Pyknosis, karyolysis, nucleus reversible and irreversible damages and membrane destruction were observed for both of the etchants at the higher concentrations and longer application durations. Mann-Whitney Utests were used for the statistical analyses. The application of the V-prep for 30 s showed better values than the acid etchant did in the cell damage analysis and cell viability analysis (p = 0.03). V-prep at a 1:10 concentration applied for a 30 s duration can preserve the viability of gingival fibroblasts cells up to 100%. The toxicity of V-prep is equal or lower than the toxicity of the acid etchant that is commonly used in dentistry. Thus, the V-prep can be used with precautions intra-orally, and it should be applied on the enamel as a gel for 30 s only before it is rinsed and removed