Variation of chemical composition of essential oils in wild populations of Thymus algeriensis Boiss. et Reut., a North African endemic Species

<p>Abstract</p> <p>Background</p> <p><it>Thymus algeriensis </it>is an endemic aromatic plant to Tunisia largely used in folk medicine and as a culinary herb. The bulks aromatic plants come from wild populations whose essential oils compositions as well as their biological properties are severely affected by the geographical location and the phase of the plant development. Therefore, the aim of the present work is to provide more information on the variation of essential oil composition of <it>T. algeriensis </it>collected during the vegetative and the flowering phases and from eight different geographical regions. Besides, influence of population location and phenological stage on yield and metal chelating activity of essential oils is also assessed.</p> <p>Methods</p> <p>The essential oil composition of <it>Thymus algeriensis </it>was determined mainly by GC/FID and GC/MS. The chemical differentiation among populations performed on all compounds was assessed by linear discriminate analysis and cluster analysis based on Euclidean distance.</p> <p>Results</p> <p>A total of 71 compounds, representing 88.99 to 99.76% of the total oil, were identified. A significant effect of the population location on the chemical composition variability of <it>T. algeriensis </it>oil was observed. Only 18 out of 71 compounds showed a statistically significant variation among population locations and phenological stages. Chemical differentiation among populations was high. Minor compounds play an important role to distinguish between chemical groups. Five chemotypes according to the major compounds have been distinguished. Chemotypes distribution is linked to the population location and not to bioclimate, indicating that local selective environmental factors acted on the chemotype diversity.</p> <p>Conclusions</p> <p>The major compounds at the species level were α-pinene (7.41-13.94%), 1,8-cineole (7.55-22.07%), <it>cis</it>-sabinene hydrate (0.10-12.95%), camphor (6.8-19.93%), 4-terpineol (1.55-11.86%), terpenyl acetate (0-14.92%) and viridiflorol (0-11.49%). Based on major compounds, the populations were represented by (α-pinene/1,8-cineole/<it>cis</it>-sabinene hydrate/camphor/viridiflorol), (1,8-cineole/camphor/terpenyl acetate), (α-pinene/1,8-cineole/camphor), (1,8-cineole/camphor/4-terpineol) and (α-pinene/1,8-cineole/<it>cis</it>-sabinene hydrate/camphor/4-terpineol) chemotypes. Variation of phenological stage did not have a statistically significant effect on the yield and metal chelating activity of the essential oil. These results can be used to investigate the geographical location and the harvesting time of this plant for relevant industries.</p

FINANCIAL INNOVATION, RISK MANAGEMENT, AND BANK PERFORMANCE

Several researches conducted from the angle of corporate governance reveals that the majority of the work that examines the direct association between financial innovation and bank performance has displayed mixed results and has ignored the indirect relationship between these two variables through the risk management of incurred by the bank. In this context, the purpose of this study is to investigate whether or not there is a mediating effect of risk management on the relationship between financial innovation and bank performance. Data collected from annual activity reports of banks listed on the Tunis Stock Exchange is analyzed, and used to validate the theoretical and empirical contributions of our article. The empirical study uses the Panel data extracted from 10 banks, over the period ranging from 2009 to 2017, and the Baron and Kenny (1986) mediation approach has been estimated, using specifications of random effects. Our empirical analysis substantiates that financial innovation has a positive direct effect on stock market performance, and a non-significative impact on financial profitability. Additionally, our results show that improving the stock market performance of banks by financial innovation depends on the mediator role of the operational risk management. To remain improving performance, Tunisian banks must pay more attention on special training of bank managers whose function relate to the choice of financial innovations and manage the associated risks

Management of Perinatal Testicular Torsion: A Single Centre Experience

Perinatal testicular torsion (PTT) is a rare entity. The management of PTT is controversial, due to the low viability of the testis and the possibility of bilateral torsion. This is a review of our experience with six cases of PTT, highlighting diagnostic and therapeutic difficulties of this condition

A Comparative Analysis between Right and Left Congenital Diaphragmatic Hernias

Congenital diaphragmatic hernia (CDH) is a rare congenital anomaly of the diaphragm with an incidence of 1:2000-5000 of live births. This study retrospectively evaluated patients who had been operated on for CDH at our department of Pediatric Surgery between January 2013 and December 2016. The Demographic Data and outcomes of right CDH cases (Group 1) were compared with left CDH cases (Group 2)

Colored Petri net Model for Secure Document Management in Business Process Systems.

International audienc

Heterologous expression and secretion of an antifungal Bacillus subtilis chitosanase (CSNV26) in Escherichia coli

The aims of the study were the production improvement, the purification, the characterization and the activity investigation of chitosanase CSNV26 of Bacillus subtilis (V26). The gene csnV26 encoding for this protein was amplified and cloned in the pBAD vector then expressed in Escherichia coli (Top10). The SDS-PAGE and zymogram analysis of the recombinant protein showed that it has two active forms sized 27 and 31 kDa, corresponding to the protein with and without signal peptide. This protein has the particularity of being secreted by Top10-pBAD-csnV26 with a high yield of 6.2 g/l. The HPLC purification of CSNV26 from supernatant confirmed the presence of the two sizes. The investigation of the CSNV26 thermostability showed that the pure protein is highly stable keeping 68 % of its activity after 30-min treatment at 100 °C, contrarily to the protein present within the supernatant of E. coli and B. subtilis (V26). The molecular dynamics study of the predicted structure of protein in both forms showed that the presence of the peptide signal in the form of 31 kDa gave it a remarkable thermal stability. The antifungal activity of CSNV26 was evidenced on Rhizopus nigricans and Rhizopus oryzae. Indeed, it has provoked an alteration and embrittlement of their hyphae with onset of protoplast

Correlation between synthesis variation of 2-alkylquinolones and the antifungal activity of aBurkholderia cepacia strain collection

Twenty epiphytic and rhizospheric bacterial strains harbouring strong antifungal activities were isolated from the Tunisian environment. This group of bacteria was identified as Burkholderia cepacia genomovar I using 16S rDNA and recA fragment gene sequence analyses for two selected strains and RFLP technique for the eighteen other ones. This identification did not show variability between isolates despite the significant differences in the antifungal activities of their culture supernatant and the organic crude extract against Aspergillus niger and other phytopathogenic fungi. Chromatographic and mass spectrometric analyses of these extracts allowed us to confirm the difference between strains of the group. Their metabolic production showed differences in term of contents and quantities of secreted molecules, particularly those which were identified to be involved in the antifungal activities. Two metabolites, named Bc-255 and Bc-257 secreted by the entire group at different amounts, have been purified and tested separately against A. niger. Bc-255 showed an activity twice as high as those shown by Bc-257. The structural characterization of these two compounds by mass spectrometry and nuclear magnetic resonance spectroscopy allowed their identification as two analogous 2-alkylquinolones with only one difference at the alkyl chain.Ministry of Higher Education and Scientific Researc

Three-Level NPC Inverter-Fed IM Drives under PTC, Minimizing the Involved Voltage Vectors and Balancing the DC Bus Capacitor Voltages

The paper presents a comparative study of the steady-state and transient behaviors of three-level neutral-point clamped (3L-NPC) inverter-fed induction motor (IM) drives under the control of three predictive torque control (PTC) schemes: the conventional one (C-PTC) and two new strategies involving selected stator voltage vectors (SVs), namely: (SV-PTC1) and (SV-PTC2). Compared to the C-PTC, the latter enable a reduction of the number of voltage vectors as well as the weighting factors. The introduced PTCs mainly differ by the cost function, which is more simple in the case of SV-PTC2. However, SV-PTC1 allows a systematic clamping of each stator phase to the DC bus voltage, at a low level of 60 degrees, and a high level at 60 degrees per cycle, while such a clamping is arbitrary in the case of SV-PTC2. Simulations prove the higher performances of the introduced SV-PTCs over the C-PTC ones, in terms of the reduction of the current distortion and of the torque ripple. Simulation results were validated by the experiments

The SBAR tool for communication and patient safety in gynaecology and obstetrics: a Tunisian pilot study

Abstract Background In healthcare, inadequate communication among providers and insufficient information transmission represent primary contributors to adverse events, particularly in medical specialties such as obstetrics and gynecology. The implementation of SBAR (Situation-Background-Assessment-Recommendation) has been proposed as a standardized communication tool to enhance patient safety. This study aims to evaluate the knowledge, attitudes, and practices related to SBAR communication through a pilot study conducted in a middle-income country. Methods This prospective longitudinal study took place in the gynecology-obstetrics department of a Tunisian university hospital from May to June 2019. All medical and paramedical staff underwent comprehensive theoretical and practical training through a 4-hour SBAR simulation. To gauge participants’ knowledge, anonymous multiple-choice questionnaires were administered before the training initiation, with a second assessment conducted at the end of the training to measure satisfaction levels. Two months later, the evaluation utilized questionnaires validated by the French National Authority for Health (HAS). Results Among the 62 care staff participants in this study, a majority (89%) demonstrated a low level of knowledge regarding the SBAR tool. The majority (75.8%) expressed enjoyment with the training and indicated their intention to implement changes in their practice by incorporating the SBAR tool in the future (80.7%). Notably, over half of the participants (79%) expressed satisfaction with the training objectives, and 74% reported acquiring new information. Evaluation of the practice revealed positive feedback, particularly in terms of clarity, the relevance of communication, and the time spent on the call. Conclusion Our pilot study showed that the majority of professionals on the ward had little knowledge of the SBAR tool, a good attitude and a willingness to put it into practice. It is essential that healthcare managers and professionals from all disciplines work together to ensure that good communication practice is developed and maintained. Organisations, including universities and hospitals, need to invest in the education and training of students and health professionals to ensure good quality standardised communication