Essai préliminaire de corrélations entre paramètres altérologiques normatifs et caractéristiques physico-mécaniques des roches et des produits d'altération de la série de Mbalmayo-Bengbis (Sud - Cameroun), à l'usage du génie civil

The normative alterological reconstruction system, contrary to other methods of genetic characterization of soils, is, according to our present knowledge, the most appropriate method that gives results thatare compatible with geotechnical experiments. The interface between fundamental studies and their applications to geotechnics is very less studied and the relevant works that have been carried out on thistheme since the mid 80s have led to a very elaborated normative alterology version. This version has been applied to the study of schistose rocks and their weathering materials in the south of Cameroon. Major elements concentrations were determined by X-ray fluorescence (XRF) after sample ignition. FeO concentrations were determined by potassium dichromate titration. Rock sample powders were prepared for inductively coupled plasma-mass spectrometry analyses (ICP-MS) for lithophile trace element concentrations by acid digestion in closed beakers. These chemical analyses were used to determine the alterogical parameters. The geotechnical analyses were done in the National Civil Engineering Laboratory of Cameroon (LABOGENIE). The results obtained show good correlations between the alterological parameters of the studied materials and their physical and mechanical characteristics. The chlorite schistsand the weathered materials from the lower alteritic and the median nodular horizons are usable in civil engineering works only after  mechanical crushing. The surface clayey materials can be used in the production of bricks and roofing tiles. The present study aims at clearly linking the fundamental genetic data of the material studied to a few of their physical and mechanical properties, and to precisely give theiruse in civil engineering works.Key words: South Cameroon - Chlorite schists - Laterites - Normative alterological reconstructionsystem -Geotechnics.La méthode de restructuration altérologique normative, contrairement aux autres modes de caractérisation génétique des sols, est, à notre  connaissance, la plus apte à fournir à l'heure actuelle des résultats compatibles avec l'expérimentation géotechnique. Cette interface entre études fondamentales et applications en géotechnique est très peu étudiée. Ses nombreux développements depuis le milieu des années 80 ont abouti à une version très élaborée. Cette dernière a été appliquée à l'étude des roches schisteuses et à celle des produits dérivés de leur altération dans le sud du Cameroun. Les analyses chimiques des éléments majeurs ont été effectuées par Fluorescence X et par titrimétrie (FeO) et, celles des éléments en traces par ICP-MS, en vue de l'évaluation des paramètres altérologiques normatifs. Les analyses géotechniquesont été réalisées au Laboratoire National de Génie Civil du Cameroun (LABOGENIE). Les résultats obtenus montrent de bonnes corrélations entre les paramètres altérologiques des matériaux étudiés et leurs caractères physiques et mécaniques. Les chloritoschistes et les produits d'altération des niveaux inférieurs altéritiques et médians nodulaires sont exploitables dans les travaux du génie civil seulement après concassage. Les matériaux argileux du niveau de surface sont utiles à la fabrication des tuiles et des briques. Le présent travail a pour but de lier clairement les données génétiques fondamentales des matériaux étudiés à quelques unes de leurs propriétés physiques et mécaniques et de préciser l'utilité de ces derniers dans les travaux de Génie.Mots-clés : Sud Cameroun - Chloritoschistes - Latérites - Restructuration altérologique normative - Géotechnique

DEVELOPMENT AND VALIDATION OF STABILITY INDICATING REVERSE PHASE HIGH‑PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD FOR THE ESTIMATION OF PIRIBEDIL IN BULK DRUG

ABSTRACTObjective: A simple, precise, fast, economic, accurate, robust, and stability indicating isocratic reverse phase high-performance liquid chromatographicmethod was developed for the analysis of Piribedil.Method: The chromatographic conditions were standardized using Unisol C-18 (4.6 × 150 mm × 3.0 μ) column with UV detection at 244 nm, and themobile phase composed of methanol:acetate buffer-pH 5.0 (85:15, v/v).Results: The retention time of Piribedil was found to be 3.4 minutes. The calibration curve was linear with correlation coefficient of 0.999 over aconcentration range of 20-100 μg/ml with linear regression equationy=74,69,224.37x−39,46,924.90. The limit of detection and limit of quantitationwere found to be 0.04 and 0.4 μg/ml, respectively.Conclusion: The proposed method has been validated according to the ICH guidelines. Piribedil was subjected to stress conditions includingacidic, alkaline, oxidation, photolysis, and thermal degradation. Piribedil is more sensitive to photolytic stress. There are no interfering peaks fromdegradation products at analyte retention time, and thus the method is specific for the estimation of Piribedil in the presence of degradation products.Thus, the proposed method can be successfully applied in the routine quality control and stability samples of Piribedil in bulk drug.Keywords: Piribedil, Validation, Stability indicating, Reverse phase high-performance liquid chromatographic

DEVELOPMENT AND VALIDATION OF UV SPECTROPHOTOMETRIC AND REVERSED PHASE‑HIGH PERFORMANCE LIQUID CHROMATOGRAPHY ‑ PDA METHODS FOR THE ESTIMATION OF ALOGLIPTIN BENZOATE

Objective: To develop and validate simple, rapid, precise, accurate, and economical UV spectrophotometric and reverse phase high performanceliquid chromatographic methods for the estimation of alogliptin benzoate (AGP).Methods: UV spectrophotometric method was performed using UV/Vis double beam spectrophotometer with a spectral bandwidth of 1 nm and1.0 cm matched quartz cells. The maximum absorbance of AGP was observed at 276 nm using methanol as solvent. Reversed phase-high performanceliquid chromatography (RP-HPLC) method was carried out on a Unisol reverse phase C18 column (150 mm × 4.6 mm, 3 μm) with a mobile phasecomposed of methanol and 10 mM ammonium acetate buffer (adjusted to pH 5.0 with glacial acetic acid) in the ratio of 80:20 v/v with a flow rate of0.8 ml/minutes.Results: The linearity of methods was found to be in the range of 5-35 µg/ml (UV) and 20-100 µg/ml (RP-HPLC) and the correlation coefficient was0.999 for both the methods. The regression equations were y = 0.028x + 0.023 (UV) and y = 28,58,942x - 4,33,647 (HPLC). The retention time of AGPwas 2.37 minutes.Conclusion: The proposed methods were validated in terms of linearity, precision, accuracy, specificity, robustness, limit of detection, and limit ofquantitation as per International Conference on Harmonization Q2 R1 guidelines. Thus, the proposed methods are novel, sensitive, and reliable andcan be successfully used for the quantitation of AGP.Keywords: Alogliptin benzoate, UV-visible spectrophotometer, Reversed phase-high performance liquid chromatography, International Conferenceon Harmonization guidelines

The Spin Structure of the Nucleon

We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure

Treatment of depressive disorders in primary care - protocol of a multiple treatment systematic review of randomized controlled trials

Background: Several systematic reviews have summarized the evidence for specific treatments of primary care patients suffering from depression. However, it is not possible to answer the question how the available treatment options compare with each other as review methods differ. We aim to systematically review and compare the available evidence for the effectiveness of pharmacological, psychological, and combined treatments for patients with depressive disorders in primary care. Methods/Design: To be included, studies have to be randomized trials comparing antidepressant medication (tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), hypericum extracts, other agents) and/or psychological therapies (e.g. interpersonal psychotherapy, cognitive therapy, behavioural therapy, short dynamically-oriented psychotherapy) with another active therapy, placebo or sham intervention, routine care or no treatment in primary care patients in the acute phase of a depressive episode. Main outcome measure is response after completion of acute phase treatment. Eligible studies will be identified from available systematic reviews, from searches in electronic databases (Medline, Embase and Central), trial registers, and citation tracking. Two reviewers will independently extract study data and assess the risk of bias using the Cochrane Collaboration's corresponding tool. Meta-analyses (random effects model, inverse variance weighting) will be performed for direct comparisons of single interventions and for groups of similar interventions (e.g. SSRIs vs. tricyclics) and defined time-windows (up to 3 months and above). If possible, a global analysis of the relative effectiveness of treatments will be estimated from all available direct and indirect evidence that is present in a network of treatments and comparisons. Discussion: Practitioners do not only want to know whether there is evidence that a specific treatment is more effective than placebo, but also how the treatment options compare to each other. Therefore, we believe that a multiple treatment systematic review of primary-care based randomized controlled trials on the most important therapies against depression is timely

Peripheral blood and neuropsychological markers for the onset of action of antidepressant drugs in patients with Major Depressive Disorder

<p>Abstract</p> <p>Background</p> <p>In Major Depressive Disorder (MDD), treatment outcomes with currently available strategies are often disappointing. Therefore, it is sensible to develop new strategies to increase remission rates in acutely depressed patients. Many studies reported that true drug response can be observed within 14 days (early improvement) of antidepressant treatment. The identical time course of symptom amelioration after early improvement in patients treated with antidepressants of all classes or with placebo strongly suggests a common biological mechanism, which is not specific for a particular antidepressant medication. However, the biology underlying early improvement and final treatment response is not understood and there is no established biological marker as yet, which can predict treatment response for the individual patient before initiation or during the course of antidepressant treatment. Peripheral blood markers and executive functions are particularly promising candidates as markers for the onset of action and thus the prediction of final treatment outcome in MDD.</p> <p>Methods/Design</p> <p>The present paper presents the rationales, objectives and methods of a multi-centre study applying close-meshed repetitive measurements of peripheral blood and neuropsychological parameters in patients with MDD and healthy controls during a study period of eight weeks for the identification of biomarkers for the onset of antidepressants' action in patients with MDD. Peripheral blood parameters and depression severity are assessed in weekly intervals from baseline to week 8, executive performance in bi-weekly intervals. Patients are participating in a randomized controlled multi-level clinical trial, healthy controls are matched according to mean age, sex and general intelligence.</p> <p>Discussion</p> <p>This investigation will help to identify a biomarker or a set of biomarkers with decision-making quality in the treatment of MDD in order to increase the currently disappointing remission rates of antidepressant treatment.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00974155">NCT00974155</a></p