Étude de la compétitivité de complexation des métaux issus des phosphates naturels de Hahotoé-Kpogamé par les substances humiques

Le phosphate naturel de par sa formule chimique constitue une source importante de l’élément phosphore pour les plantes. Pour cela il est utilisé dans le compost pour améliorer les qualités nutritionnelles des plantes. Les analyses chimiques effectuées sur le phosphate naturel révèlent la présence des métaux lourds. Pour étudier les risques de rétrogradation de ces engrais phosphatés, notre étude s’est portée sur la complexation des substances humiques naturelles extraites des sols sur des ions métalliques tels que le calcium, cadmium et le magnésium contenus dans les phosphates naturels de Hahotoé- Kpogamé du Togo. Les résultats obtenus montrent que la quantité d’ions complexés augment avec le temps d’attaque. Le taux d’ions complexés diminue lorsque le pH de la solution d’acide humique évolue de 6,5 à 9,5. Une étude comparative de la complexation de ces trois ions révèle que le cadmium malgré sa faible teneur dans le phosphate naturel se complexe mieux que le calcium et le magnésium. Après 30 jours d’attaque du phosphate naturel nous avons obtenu un taux avoisinant les 10% pour le cadmium, 9% pour le calcium et environ 2% pour le magnésium pour une solution d’acide humique de pH=6,5.Mots-clés : complexation, métaux lourds, phosphate naturel, rétrogradation, substances humiques.Study on competitiveness of metals after complexation of phosphate rock in Hahotoè-Kpogamé by humic substancesPhosphate by its chemical constitution is an important source of the phosphorus element for plants. Thus, it is used in compost to improve the nutritional qualities of plants. Chemical analyzes of the phosphate reveal the presence of heavy metals. To assess the risk of the phosphate fertilizer downgrading, our study focused on calcium, magnesium, and cadmium ions contents in the humic substances extracted from soils fertilize with Hahotoè-Kpogamé (Togo) phosphate. The results show that the amounts of ions in the complexed humic substances increase with the attack time. The complexed ions rate decreases as the pH of the solution of humic acid changes from 6.5 to 9.5. Despite the low cadmium content in the rock phosphate, this element is more easily assimilated in complex than its two analogous. After 30 days of phosphate attack, a humic acid solution at pH = 6.5 gave a rate of about 10% for cadmium, 9% for calcium and 2% magnesium.Keywords : complexation, heavy metal, rock phosphate, downgrading, humic substances

Intramedullary fixation of boxer's fractures: evaluation of functional results

Introduction: The majority of the fifth metacarpal neck fractures can be treated conservatively. Nevertheless, surgical treatment is justified in certain cases. This retrospective study was designed to evaluate the clinical results of intramedullary Kirschner-wire fixation of these fractures. Material and methods: Between May 2005 and January 2006, 42 patients (40 men and 02 female) with 42 displaced fifth metacarpal neck fractures were treated at out institution by closed intramedullary Kirschner wires fixation. The assessment of patients was based on the time to union, the functional recovery and the incidence of complications. Results: Fractures were treated by intramedullary stabilization with, on median, two k-wires, with the k-wires having a median diameter of 1.4 mm. Median operating time was 30 minutes. Initial fracture angulation measured on the lateral radiographs averaged 39° in excess of the normal head shaft angle. On the immediate post operative radiographic, fracture angulation averaged 6°, designating an average 95% correction of the initial angulation. Union occurred in all patients. The average time to union was 8,4 weeks. There were eight postoperative complications: two superficial infections, and six mechanical irritations of the Kwires. The pins were removed in 40 cases. Removal of the pins was performed in all cases as an outpatient procedure under local anaesthetic with no complications noted. At final follow-up, fracture angulation averaged 6.9° . The average MCP arc of motion at the last follow-up was 95° (range, 85 - 105). Many of the patients (23 patients) had less than 50% of normal function immediately after union of the fractures but improved considerably by 2 weeks and all had more than 90% (90% - 100%) normal function at 2 months post operative. Discussion: The X-rays of the metacarpal fractures in our patients showed, on median, a palmar dislocation of 39°, which is why closed reduction and intramedullary k-wire stabilization was performed. Compared with the other available surgical methods, intramedullary fixation of metacarpal bones is characterized by its simplicity and the fact that fracture treatment does not harm the sliding tissue. Conclusion: Intramedullary Kirschner wire fixation is a minimally invasive method for stabilizing the fifth metacarpal neck fractures.Key-words: Metacarpal fractures, Internal fixation, Intramedullary Kirschner wir

Prise en charge des traumatismes fermes du thorax chez l’adulte au c.h.u. Tokoin de Lome.

We performed a retrospective study on 348 files of patients hospitalised for closed thoracic trauma during 10 years (1990-1999). The objective was the evaluation of its management. 278 men (79.9%) and 70 women (20.1%) were concerned (sex ratio = 4) and the mean age was 35.7 years. Road accidents were the first etiology (73.56%). Pulmonary contusion in 170 patients (48.85%) was the most frequent thoracic injury followed by 154 (44.25%) cases of rib fractures, 72 (20.70%) cases ofhemothorax and 49 (14.08%) cases of pneumothorax. 53 (15.23%) chest tube were placed. 4 thoracotomy and one sternotomy were performed. Death occurred in 27 (7.76%) cases and was mainly related to the presence of associated injuries. X ray remains useful. An improvement of survival needs creation of a department of thoracic surgery. Nous avons rétrospectivement analysé 348 dossiers de traumatismes fermés du thorax recensés sur 10 ans (1990 -1999). Le but de notre travail était d’en analyser la prise en charge. Les 348 patients serépartissaient en 278 hommes (79,9%) et 70 femmes (20,1%) avec une sex-ratio de 4. L'âge moyen était de 35,7 ans. Les accidents de la voie publique ont constitué la première étiologie (73,56%). Leslésions thoraciques étaient dominées par les contusions pulmonaires (48,85%), suivies des fractures de côtes (44,25%), puis de 72 cas (20,70%) d'hémothorax et de 49 cas (14,08%) de pneumothorax ; 53drains (15,23%) ont été placés. Quatre thoracotomies et une sternotomie ont été réalisées. 27 décès furent enregistrés (7,76%), en rapport surtout avec les lésions associées extrathoraciques. Laradiographie standard reste utile. Une amélioration de la survie passe par l’installation d’un service de chirurgie thoracique