A route to possible civil engineering materials: the case of high-pressure phases of lime.

Lime system has a chemical composition CaO, which is known as thermodynamically stable. The purpose here is to explore further possible phases under pressure, by means of variable-composition ab initio evolutionary algorithm. The present investigation shows surprisingly new stable compounds of lime. At ambient pressure we predict, in addition to CaO, CaO2 as new thermodynamically stable compound. The latter goes through two phases transition from C2/c space group structure to Pna21 at 1.5 GPa, and Pna21 space group structure to I4/mcm at 23.4 GPa. Under increasing pressure, further compounds such as CaO3 become the most stable and stabilize in P-421m space group structure above 65 GPa. For the necessary knowledge of the new predicted compounds, we have computed their mechanical and electronic properties in order to show and to explain the main reasons leading to the structural changes.

Can clays ensure nuclear waste repositories?

Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmorillonite with respect to calcite. Under anisotropic stress, we have observed a shear deformation of the assembly with the presence of broken bonds in the clay mineral, localised in the octahedral rather than the tetrahedral layers. The stress/strain curve leads to a failure strength point at 18.5 MPa. The obtained in-plane response of the assembly to perpendicular deformation is characterized by smaller perpendicular moduli Ez = 48.28 GPa compared to larger in-plane moduli Ex = 141.39 GPa and Ey = 134.02 GPa. Our calculations indicate the instability of the assembly without water molecules at the interface in addition to an important shear deformation.

High-pressure polymorphs of ZnCO3: evolutionary crystal structure prediction.

The high-pressure behavior of zinc carbonate ZnCO3 has been investigated using universal structure prediction method together with the density functional theory. In order to explore all possible structures under pressure, separate calculations at high pressure are done here with increasing number of formula units in the unit cell. Two pressures induced phase transitions were considered. The first one occurs at 78 GPa and the second one at 121 GPa. The most stable ZnCO3 at ambient condition corresponds to the space group R-3c (phase I), which is in favorable agreement with experiment. The structure with C2/m space group (phase II) becomes stable between 78 GPa and 121 GPa. Finally, the structure with the space group P2(1)2(1)2(1) (phase III) becomes the most stable when the pressure achieves 121 GPa. Some mechanical properties of R-3c structure were -additionally- calculated and compared with the experimental and previous theoretical data. The resulting behaviors support our findings and confirm the obtained phase transition. Besides, from the analysis of the electronic charge density it comes that at 78 GPa, new bond between oxygen and zinc is formed, what is likely the main cause behind the phase transition.

[Not Available]. / Diagnostic clinique et paraclinique des infections ostéoarticulaires digitales dans les brûlures thermiques de la main.

Infectious complications of finger-joints in association with hand burns are common and dominated by osteoarthritis. However, this issue has hardly ever been addressed in the literature. This ailment can either be identified while patients with extensive burns are undergoing intensive care, or during patient rehabilitation. In the former instance, it is difficult to recognize because patient sedation means the clinical signs are not obvious. In the latter phase, however, the pain, swelling (tumefaction), stiffness and radiological signs are clear. These infections should be diagnosed as soon as possible in order to preserve the function of the hand.

Behind adhesion of uranyl onto montmorillonite surface: a molecular dynamics study.

We have performed molecular dynamics simulations to investigate the adsorption of radionuclide elements species onto substituted Montmorillonite (001) surface in the presence of different counterions. The structure and the dynamics of uranyl ion as well as its aquo, chloride ion, and carbonate complexes are analyzed. In addition, we have studied the surface energy between layered Montmorillonite sheets and the work of adhesion between radionuclide and charged Montmorillonite. The clay model used here is a Wyoming-type Montmorillonite with 0.75e negative charge per unit cell resulting from substitutions in Octahedral and Tetrahedral sheets. The system model was constructed based on CLAYFF force field potential model. To evaluate the thermodynamic work of adhesion, each surface and clay layer regions are converted to a thin film model. One and two species of radionuclide elements (UO2(H2O)5,UO2CO3(H2O)5, and UO2Cl2(H2O)5) were deposited near the clay surface in a pseudo-two-dimensional periodic cell. Analysis shows that the uranyl ion structure is preserved with two axial oxygen atoms detected at 1.8Å. Radial distribution functions results indicate that average UOw distances are 2.45-2.61Å, and 2.29-2.40Å for UOc distance. Average UCl distances are 2.78-3.08Å, which is relatively larger than that of Uranium atom-Oxygen atom because of electrostatic factors.

Nanoscale analysis of the morphology and surface stability of calcium carbonate polymorphs.

Under earth surface conditions, in ocean and natural water, calcium carbonate is ubiquitous, forming anhydrous and hydrous minerals. These hydrous phases are of considerable interest for their role as precursors to stable carbonate minerals. Atomistic simulation techniques have been employed here to perform a comprehensive and quantitative study of the structural and energetic stability of dry and hydrous surfaces of calcium carbonate polymorphs using two recently developed forcefields. Results show that the dry forms are prone to ductility; while hydrous phases are found to be brittle. The (001) surface of monohydrocalcite appears to be the most stable (0.99 J/m(2)) whereas for the ikaite phase, the (001) surface is the most stable. The corresponding value is 0.2 J/m(2), i.e. even lower than the surface energy of the Beautiful computed morphology pictures are obtained with Xiao's model and are very similar to the observed SEM images.

Patients with complicated Pott's disease: management in a rehabilitation department and functional prognosis.

OBJECTIVE: The objective is to study the rehabilitation management and to assess autonomy in daily life activities as well as walking recovery in patients with complicated Pott's disease. PATIENTS AND METHODS: Retrospective study in nine patients over a period of 8 years extending from 2000 to 2008, collated in the Department of Physical Medicine and Functional Rehabilitation, CHU Sahloul, Sousse, Tunisia. RESULTS: The mean age of our patients was 43.8 years; sex ratio was 5/4. The spine involvement of tuberculosis was dorsal in seven cases, dorso-lumbar in one patient, and multiple (cervical, dorsal and lumbar) in one case. All patients were paraplegic with a neurological involvement of the bladder. They had prior antituberculosis chemotherapy for at least 8 months. Decompression surgery was performed in six cases. Two female patients presented disorders of spinal posture during treatment requiring surgical revision with osteosynthesis. All patients received additional rehabilitation care. Following a mean duration of hospitalisation in the Rehabilitation department of 47 days with twice-daily sessions of tailored physiotherapy, three patients remained in complete paraplegia, autonomous in wheel-chair and with vesical and sphincter incontinence. The measure of functional independence (MFI) was at admission/discharge 71/92. CONCLUSION: Rehabilitation takes an important place in the medico-surgical management in Pott's disease, to limite or compensate the disabilities and handicap related to this pathology.

[Investigation of the prevalence of nosocomial infection in a Tunisian regional hospital]. / Prévalence de l'infection nosocomiale dans un hôpital régional tunisien.

Nosocomial infections (NI) have achieved an increasingly large prevalence today, in Tunisia as well as abroad. Their on-going presence and occurrence are largely responsible for increasing morbidity and sometimes mortality. The aim of this work is to determine the prevalence of NI in the Kebili regional hospital and assess its level of impact. It consists of a cross-cutting study conducted in the Kebili regional hospital which holds 124 beds dispersed throughout 6 units. All of the patients hospitalised for more than 48 hours and who were present in the hospital between midnight February 17th to midnight February 18th, 2004, were included in the study. In the small hospital, 64 patients were present on the day of the study, 45 of whom had been already been hospitalised for over 48 hours. Among these 45, 6 patients (13%) tested positive for a NI. This prevalence is higher than that which is reported in the literature (2-3-9). The proportion of NI in this study is closer to that described in other series (2-7). In fact, we recorded the following : 2 cases of infection in the body zone operated upon (33%), 2 cases of urinary infection (33%), 1 case of pneumonia (17%), and 1 case of a skin infection (17%). The microbiological documentation, as it is described and presented in the other studies (1-7), was not found in our 6 patients here. The association and linkage between NI and certain other factors related to the provision of care has been documented as follows: surgical intervention, manipulations of the veins, gall bladder probing (or insertion of a catheter), tracheotomy, and prolonged hospitalisation (with an average stay of 16.5 days). The strong relationship between the occurrence of NI and the type of service or intervention administered during a hospital stay described in a select number of studies (2-5-7-11) does not present itself in our results. The overprescription of antibiotics among the patients in the hospital (52%) can be interpreted as a poor control mechanism and insufficient surveillance of the prescriptions and the delivery of these antibiotics, which serves as an important factor which contributes to NI and the development of resistance to available treatment. The work attempts to underline the importance of such a study on NI for the development and improvement of the quality of care, most importantly because the occurrence of NI constitutes a public health problem, and this is related to both the high prevalence of NI and its human and economic costs. In spite of the deficiencies noted in the clinical diagnoses and most notably the microbiological diagnoses, nosocomial infections are present in our hospital with a prevalence of 13%.

Fundamental state quantities and high-pressure phase transition in beryllium chalcogenides.

In this work we study the structural and electronic properties of Be chalcogenides (BeS, BeSe and BeTe) using two different methods: the full-potential linear augmented-plane wave (FP-LAPW) and the plane-wave pseudopotential (PPsPW). The exchange-correlation effects are treated in the local-density approximation (LDA) and the generalized-gradient approximation (GGA). We have evaluated the ground-state quantities such as equilibrium volume, bulk modulus and its pressure derivative as well as the elastic constants. Various structural phase transitions were considered here in order to confirm the most stable structure and to predict the phase transition under hydrostatic pressure. In addition we have studied the band structure and the density of states, which show a wide indirect band gap for these compounds. These results were in favourable agreement with previous theoretical works and the existing experimental data. To complete the fundamental characteristics of beryllium chalcogenide compounds we have analysed their bonding character in terms of charge transfer and the ionicity parameter. The latter is found to be in agreement with the charge transfer behaviour, which shows an important ionic localization.

[Nonsurgical treatment of tennis elbow]. / Les traitements non chirurgicaux de la tendinopathie des épicondyliens.

OBJECTIVE: To review the literature on nonsurgical treatment of tennis elbow. METHODS: We searched Medline for all randomized controlled trials (RCTs), controlled clinical trials (CCTs) and literature reviews published from 1966 to December 2003 on nonsurgical treatment of tennis elbow. We used the keys words controlled clinical trial, tennis elbow on lateral epicondylitis, and treatment. We found 46 reports of RCTs and CCTs on 14 nonsurgical treatments and 11 literature reviews. RESULTS: Corticosteroid injection is the best treatment option for the short term. However, beneficial effects persisted only for a short time, and the long-term outcome could be poor. For the long term, physiotherapy (pulsed ultrasound, deep friction massage and exercise programme) was the best option but was not significantly different from the "wait-and-see" approach. Some support is offered for the use of topical nonsteroid anti-inflammatory drugs, at least for the short term. There is insufficient evidence to support or refute the use of acupuncture, extracorporeal shock wave therapy, manipulation, orthoses, low-energy laser, glycosaminoglycan polysulfate injection, botulinum toxin injection, or topical nitric oxide application. CONCLUSION: Further trials, with use of appropriate methods and adequate sample sizes, are needed before conclusions can be drawn about the effects of many of the treatments for tennis elbow and their ability to change the condition's natural course.

Acute and chronic toxicity of Nigella sativa fixed oil.

We investigated the toxicity of the fixed oil of Nigella sativa L seeds in mice and rats through determination of LD50 values and examination of possible biochemical, hematological and histopathological changes. The acute toxicity of Nigella sativa fixed oil was investigated in mice. LD50 values, obtained by single doses, orally and intraperitoneally administered in mice, were 28.8 ml/kg body wt. p.o. [26.2-31.6] and 2.06 ml/kg body wt. i.p. [1.86-2.26], respectively. Chronic toxicity was studied in rats treated daily with an oral dose of 2 ml/kg body wt. for 12 weeks. Changes in key hepatic enzymes levels, including aspartate-aminotransferase, alanine-aminotranferase, and gamma-glutamyltransferase and histopathological modifications (heart, liver, kidneys and pancreas) were not observed in rats treated with Nigella sativa after 12 weeks of treatment. The serum cholesterol, triglyceride and glucose levels and the count of leukocytes and platelets decreased significantly, compared to control values, while hematocrit and hemoglobin levels increased significantly. A slowing of body weight gain was also observed in Nigella sativa treated rats, as compared to control animals. The low toxicity of Nigella sativa fixed oil, evidenced by high LD50 values, key hepatic enzyme stability and organ integrity, suggests a wide margin of safety for therapeutic doses of Nigella sativa fixed oil, but the changes in hemoglobin metabolism and the fall in leukocyte and platelet count must be taken into consideration.

Effects of Nigella sativa fixed oil on blood homeostasis in rat.

We investigated the effects of the fixed oil of Nigella sativa seeds in rats by monitoring blood homeostasis and body weight as well as toxicity. Animals were treated daily with an oral dose of 1 ml/kg body weight of the N. sativa seed fixed oil for 12 weeks. Changes in key hepatic enzymes levels were not observed in N. sativa treated rats after 12 weeks of treatment. The serum cholesterol, triglycerides and glucose levels and the count of leukocytes and platelets decreased significantly by 15.5, 22, 16.5, 35 and 32%, compared to control values, respectively; while haematocrit and haemoglobin levels increased significantly by 6.4 and 17.4%, respectively. In parallel, significant slowdown of the body weight evolution was observed in N. sativa treated animals comparatively to the animal control group. On the other hand, no mortality was noted for ten times the therapeutic dose in mice, during 15 days period after the oil administration (10 ml/kg p.o.). These results support the traditional use of N. sativa seeds as a treatment of the dyslipidemia and the hyperglycaemia, and related abnormalities; however, indicate a relative toxicity of this plant. Acute and chronic toxicity, and the mode of the action of the N. sativa fixed oil must be studied.

[Diuretic and hypotensive effects of Nigella sativa in the spontaneously hypertensive rat]. / Effets diurétiques et hypotenseurs de Nigella sativa chez le rat spontanément hypertendu.

Nigella sativa (ranunculaceae) is used in Arab folk medicine as a diuretic and hypotensive plant. We report here the diuretic and hypotensive effects of dichloromethane extract of Nigella sativa seeds in the spontaneously hypertensive rat (SHR). An oral dose of Nigella sativa extract (0.6 ml/kg/day) and furosemide (5 mg/kg/day) increased significantly the diuresis by 16 and 30 per cent respectively after 15 days of treatment; urinary excretion of Cl-, Na+, K+ and urea is also increased. Simultaneously, the mean arterial pressure decreased respectively by 22 and 18 per cent in the Nigella sativa treated rat and nifédipine treated rat (0.5 mg/kg/day). In conclusion, the diuretic activity observed in the SHR rat treated with Nigella sativa seeds may be partially responsible for its diuretic action; it seems that other pathways may also be involved in their cardiovascular effects.

Piezoreflectance spectra of 1s Z12 exciton in CuBr.

We have investigated the piezoreflectance spectra (deltaR/R) of the 1s Z12 exciton in single crystals of copper bromide CuBr at the temperature of 95 K with linearly polarized light. The spectra were successively studied with the pressure p along the [001] and [111] axis and the wave vector k of the incident light parallel to the [110] direction. The shear deformation potentials b and d of the 1s Z12 exciton were deduced from the stress-induced shift and splitting. The results are compared with those obtained in other works.

[Desensitization by autologous saliva and Behçet's disease]. / Désensibilisation à la salive autologue et maladie de Behçet.

Among 240 patients with Behçet's disease seen in the Internal Medicine Department of the Ibnou Rochd University Hospital, Casablanca, between January 1981 and April 1988, 44 were selected to study the effects of desensitization by autologous saliva on oral and genital aphthae and on articular manifestations. Thirty of these 44 patients received gradually decreasing dilutions of their own saliva, and 14 control patients received physiological saline. Injections were administered intradermally twice a week during 15 weeks, then once a week during one year, so that the study lasted one and a half year, from October 1986 to April 1988. No improvement of the arthritis was observed, whereas the oral aphthae were improved in 50% of the patients desensitized by their own saliva. This percentage would have raised some hopes for the treatment of these sometimes disabling lesions were it not for the fact that 50% of the controls were similarly improved. This suggests that desensitization by saliva has a placebo effect.

[Articular manifestations of Behçet's disease. Apropos of 73 cases]. / Les manifestations articulaires de la maladie de Behçet. A propos de 73 cas.

The authors report 73 cases of Behçet's disease with articular manifestations. Polyarthritis, generally considered to be rare, was found in 20.5 per cent of cases in this series. The unusual features are illustrated. Amongst them, two cases presented deforming and destructive lesions, which have been only exceptionally reported in the literature. A third case is unusual because of the association of Gougerot-Sjögren's syndrome with Behçet's disease and polyarthritis deformans. No cases of ankylosing spondylitis were observed. Lastly, the data of this series are compared with those of the literature.

Protective effects of bepridil on calcium injury of anoxic myocytes isolated from adult rat heart ventricular muscle.

Cardiac myocytes allowed to recover after the isolation procedure in a well-oxygenated medium were resistant to an extracellular Ca++ concentration of 1.5 mM. At least 90% of the isolated myocytes maintained their initial rod-shaped form after a 1-hr incubation, as well as 85% of their ATP and a low cellular content of calcium. At concentrations less than 10(-5) M, bepridil had no effect on these cells. On the other hand, when the myocytes were incubated in anaerobic conditions, 1.5 mM Ca++ was deleterious: the number of viable cells decreased by about 50%, ATP levels were lowered by 70% and the total cell calcium content increased by more than 100%. Bepridil had a biphasic effect on anaerobic cells. At concentrations below 10(7) M, the drug had a beneficial action. It restored cell viability and cellular ATP to 77 and 100% when compared to their respective level in the absence of Ca++. However, at concentrations higher than 10(-6) M, bepridil decreased the number of viable cells as well as their ATP content. At optimal concentrations, bepridil lowered the cellular calcium to its level in aerobic conditions. Without calcium addition, anoxic cells accumulated Na+ and lost K+. Calcium addition decreased Na+ accumulation by 68% and prevented the loss of K+. The Na+ and K+ content of the cells were not affected by bepridil. However, it is noteworthy that, at 10(-4) M, bepridil decreased dramatically the potassium content of the cells. In aerobic conditions, the calcium resistance of isolated ventricular myocytes may still be enhanced by Fluozol, a fluorocarbon compound which increases oxygen solubility in water.

[Selective immune deficiency in IgA. Intestinal malabsorption syndrome and mixed connective tissue disease]. / Déficit immunitaire sélectif en IgA. Syndrome de malabsorption intestinale et connectivite mixte.

We report the case of a 22-year old unmarried woman who presented with selective IgA immune deficiency, moderate intestinal malabsorption syndrome with pseudo-atrophy of the villi, and mixed connective tissue disease. Although immune deficiency and malabsorption syndrome are frequently associated, association with an autoimmune disease is rare and we were unable to find any case of association with a connective tissue disease in the literature.