The international skeletal society outreach programme in Tunisia 2011

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Compressive strength and hydration with age of cement pastes containing finely ground sand

The aim of this work is to study the possibility of using finely ground sand as a part mass addition to Portland cement. Searching the effect of addition ground sand on development of compressive strength and hydration with age of cement pastes as a function of the percentage of ground sand ( physico-chemical and chemical effect) and the fineness ( physical effect). In order to understand better the pozzolanic effect of finely ground sand (quartz), we followed the mixtures hydration (90% OPC + 10% ground sand) by X-ray diffraction. The results proved the pozzolanic reactivity of ground sand: the main reaction is the fixation of the lime coming from the cement hydration in the presence of finely ground sand, to form calcium silicate hydrate C-S-H. Moreover, finely ground sand has an optimum effect on compressive strengths when the percentage is about 10% and a 20 µm fineness. Finely ground sand, despite its crystalline structure, presents a pozzolanic reactivity. Key words: Portland cement, finely ground sand, pozzolanic effect, hydration

Proximal tibiofibular synostosis as a possible cause of a pseudoradicular syndrome: a case report

This paper presents a case report of persistent low back pain and suspected lumbar radiculopathy. A synostosis at the level of the proximal tibiofibular joint was diagnosed. After successful resection of the synostosis, the low back symptoms resolved completely. This is the first report of a proximal tibiofibular synostosis as a possible cause of referred pain proximally

Sequence-specific antimicrobials using efficiently delivered RNA-guided nucleases

Current antibiotics tend to be broad spectrum, leading to indiscriminate killing of commensal bacteria and accelerated evolution of drug resistance. Here, we use CRISPR-Cas technology to create antimicrobials whose spectrum of activity is chosen by design. RNA-guided nucleases (RGNs) targeting specific DNA sequences are delivered efficiently to microbial populations using bacteriophage or bacteria carrying plasmids transmissible by conjugation. The DNA targets of RGNs can be undesirable genes or polymorphisms, including antibiotic resistance and virulence determinants in carbapenem-resistant Enterobacteriaceae and enterohemorrhagic Escherichia coli. Delivery of RGNs significantly improves survival in a Galleria mellonella infection model. We also show that RGNs enable modulation of complex bacterial populations by selective knockdown of targeted strains based on genetic signatures. RGNs constitute a class of highly discriminatory, customizable antimicrobials that enact selective pressure at the DNA level to reduce the prevalence of undesired genes, minimize off-target effects and enable programmable remodeling of microbiota.National Institutes of Health (U.S.) (New Innovator Award 1DP2OD008435)National Centers for Systems Biology (U.S.) (Grant 1P50GM098792)United States. Defense Threat Reduction Agency (HDTRA1-14-1-0007)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF13D0001)National Institute of General Medical Sciences (U.S.) (Interdepartmental Biotechnology Training Program 5T32 GM008334)Fonds de la recherche en sante du Quebec (Master's Training Award

Agroecology and Health: Lessons from Indigenous Populations.

Purpose of reviewThe article aims to systematize and disseminate the main contributions of indigenous ancestral wisdom in the agroecological production of food, especially in Latin America. For this purpose, it is necessary to ask whether such knowledge can be accepted by academia research groups and international forums as a valid alternative that could contribute to overcome the world's nutritional problems.Recent findingsAlthough no new findings are being made, the validity of ancestral knowledge and agroecology is recognized by scientific research, and by international forums organized by agencies of the United Nations. These recommend that governments should implement them in their policies of development, and in the allocation of funds to support these initiatives. Agroecology and ancestral knowledge are being adopted by a growing number of organizations, indigenous peoples and social groups in various parts of the world, as development alternatives that respond to local needs and worldviews. Its productive potential is progressively being recognized at an international level as a model that contributes to improve the condition of people regarding nutritional food

Challenges Predicting Ligand-Receptor Interactions of Promiscuous Proteins: The Nuclear Receptor PXR

Transcriptional regulation of some genes involved in xenobiotic detoxification and apoptosis is performed via the human pregnane X receptor (PXR) which in turn is activated by structurally diverse agonists including steroid hormones. Activation of PXR has the potential to initiate adverse effects, altering drug pharmacokinetics or perturbing physiological processes. Reliable computational prediction of PXR agonists would be valuable for pharmaceutical and toxicological research. There has been limited success with structure-based modeling approaches to predict human PXR activators. Slightly better success has been achieved with ligand-based modeling methods including quantitative structure-activity relationship (QSAR) analysis, pharmacophore modeling and machine learning. In this study, we present a comprehensive analysis focused on prediction of 115 steroids for ligand binding activity towards human PXR. Six crystal structures were used as templates for docking and ligand-based modeling approaches (two-, three-, four- and five-dimensional analyses). The best success at external prediction was achieved with 5D-QSAR. Bayesian models with FCFP_6 descriptors were validated after leaving a large percentage of the dataset out and using an external test set. Docking of ligands to the PXR structure co-crystallized with hyperforin had the best statistics for this method. Sulfated steroids (which are activators) were consistently predicted as non-activators while, poorly predicted steroids were docked in a reverse mode compared to 5α-androstan-3β-ol. Modeling of human PXR represents a complex challenge by virtue of the large, flexible ligand-binding cavity. This study emphasizes this aspect, illustrating modest success using the largest quantitative data set to date and multiple modeling approaches

Critical evaluation of key evidence on the human health hazards of exposure to bisphenol A

Despite the fact that more than 5000 safety-related studies have been published on bisphenol A (BPA), there seems to be no resolution of the apparently deadlocked controversy as to whether exposure of the general population to BPA causes adverse effects due to its estrogenicity. Therefore, the Advisory Committee of the German Society of Toxicology reviewed the background and cutting-edge topics of this BPA controversy. The current tolerable daily intake value (TDI) of 0.05 mg/kg body weight [bw]/day, derived by the European Food Safety Authority (EFSA), is mainly based on body weight changes in two- and three-generation studies in mice and rats. Recently, these studies and the derivation of the TDI have been criticized. After having carefully considered all arguments, the Committee had to conclude that the criticism was scientifically not justified; moreover, recently published additional data further support the reliability of the two-and three-generation studies demonstrating a lack of estrogen-dependent effects at and below doses on which the current TDI is based. A frequently discussed topic is whether doses below 5 mg/ kg bw/day may cause adverse health effects in laboratory animals. Meanwhile, it has become clear that positive results from some explorative studies have not been confirmed in subsequent studies with higher numbers of animals or a priori defined hypotheses. Particularly relevant are some recent studies with negative outcomes that addressed effects of BPA on the brain, behavior, and the prostate in rodents for extrapolation to the human situation. The Committee came to the conclusion that rodent data can well be used as a basis for human risk evaluation. Currently published conjectures that rats are insensitive to estrogens compared to humans can be refuted. Data from toxicokinetics studies show that the half-life of BPA in adult human subjects is less than 2 hours and BPA is completely recovered in urine as BPA-conjugates. Tissue deconjugation of BPA-glucuronide and -sulfate may occur. Because of the extremely low quantities, it is only of minor relevance for BPA toxicity. Biomonitoring studies have been used to estimate human BPA exposure and show that the daily intake of BPA is far below the TDI for the general population. Further topics addressed in this article include reasons why some studies on BPA are not reproducible; the relevance of oral versus non-oral exposure routes; the degree to which newborns are at higher systemic BPA exposure; increased BPA exposure by infusions in intensive care units; mechanisms of action other than estrogen receptor activation; and the current regulatory status in Europe, as well as in the USA, Canada, Japan, New Zealand, and Australia. Overall, the Committee concluded that the current TDI for BPA is adequately justified and that the available evidence indicates that BPA exposure represents no noteworthy risk to the health of the human population, including newborns and babies

Optimization of the extractions by supercritical fluids and pressurized liquid extraction from date fruit

Resumen del trabajo presentado al XVIII Scientific Meeting of the Spanish Society of Chromatography and Related Techniques (SECyTA), celebrado en Granada del 2 al 4 de octubre de 2018.The date palm Phoenix dactylifera, a tropical and subtropical tree, belonging to the family Palmae (Arecaceae) is one of mankind’s oldest cultivated plants. Date palm has long been one of the most important fruit crops in the arid regions of the Arabian Peninsula, North Africa, and the Middle East. Dates are a major food source and income source for local populations in the Middle East and North Africa, and play significant roles in the economy, society, and environment in these areas. Date fruits have gained great importance in human nutrition owing to their rich content of essential nutrients and various biological activities (hepatoprotective, anti-genotoxic, nephroprotective, anti-allergic, neuroprotective, antiviral, antifungal. The aim of this work is to figure out set up a sample preparation method to address the composition and to explore the different activities of dates (fruit and seed) by using “green” extractions methods and to assess the differences between the varieties coming from different localities. From the seeds, oil has been extracted by a supercritical CO2 and analyzed by GC-MS. To set up the extraction conditions to have the best extract, a chemometric optimization was done. Different ranges of pressure (100-300 bar), temperature (40-80°C) and co-solvent (Ethanol: 0-10%) were chosen, then a statistical analysis was done to determine the optimum conditions (100 bar, 40°C and 10% ethanol). The oil of each extract obtained was analyzed by gas chromatography to determine the profile in fatty acids. The main fatty acid found in all the varieties was myristic acid (C14:0). From the pulp the extraction was operated by Pressurized liquid extraction (PLE). The same methodology of optimization has been used; the variables were temperature (50-150°C) and solvent composition (Ethanol 100%, water 100%, water/Ethanol 50%). To get the optimum conditions an antioxidant assay was run and the yield was evaluated and then analyzed by the same method as SFE. The optimum was determined at those conditions of temperature: 150°C and Ethanol: 72%. Then the extracts were analyzed by HPLC-MS/MS.This work was done thanks to the support and financial help of the Faculty of Science of Bizerte under the University of Carthage.Peer reviewe