Tribological performance of high chromium white cast iron and heat-treated steel used in barite crushing industry.

Barite sulfate (BaSO4) is considered a very important mineral material employed as a weighting agent for all types of drilling fluids. Meanwhile, crushers used for the grinding step during barite crushing are affected by catastrophic wear damage located in the hammer parts made from high chromium white cast iron (HCWCI). In the present study, a comparison of the tribological performance between HCWCI and heat-treated steel AISI P20 was conducted to investigate the possible substitution of HCWCI. The tribological test was performed under normal loads between 5 and 10 N for different durations (60, 120, 180, and 240 min). The wear response analysis for both materials showed that the friction coefficient increases as the applied load increases. Moreover, AISI P20 presented the lowest value compared to that attributed to HCWCI in all conditions. Furthermore, the analysis of the wear track obtained by means of scanning electron microscopy (SEM) revealed that the damage was an abrasive wear phenomenon for HCWCI with detection of a crack network throughout the carbide phase, which was more pronounced under the highest load. Regarding AISI P20, an abrasive wear mechanism was detected, characterized by several grooves and ploughing phenomena. Further, the analysis of the wear track using 2D profilometry revealed that for both loads, the maximum wear depth of the HCWCI wear track was significantly greater than that of AISI P20. As a result, when compared to HCWCI, AISI P20 exhibits the best wear resistance. Furthermore, as the load increases, the wear depth and the worn area increase as well. Also, the wear rate analysis supports the previous findings, which showed that under both loads, AISI P20 was more robust than HCWCI.

The role of patients' families in treatment decision-making among adult cancer patients in the Sultanate of Oman.

There are limited numbers of studies available in Middle Eastern Arabic countries regarding participation of family members in cancer treatment decision-making (TDM). The aim of this study was to evaluate the role of family members' in TDM among adult Omani cancer patients. A cross-sectional study was conducted in two main teaching hospitals. All adult Omani patients who were diagnosed with cancer and their nominated family members were invited to participate. A tool developed by Cancer Care Outcomes Research and Surveillance Consortium was used to identify the level of family involvement in TDM. A weighted kappa (k) was significant (p < .001) and showed almost full agreement between the patients' experiences and their preferences ( k = .98) and between family members' experiences and their preferences ( k = .96) of family involvement in TDM. Binary logistic regression showed significant family-controlled TDM if the patient communicated less with oncologists (OR = 9.89; 95% CI: 3.79-25.81); financial dependence of the patient on their families (OR = 6.21; 95% CI: 2.19-17.10 ); and advanced stages of cancer at the time of diagnosis (OR = 3.10; 95% CI: 1.37-7.03). Oncologists in Oman should be aware of the strong family involvement in TDM to allow a successful cancer treatment.

Epidemiological survey of vector-borne infections in equids from northern Tunisia.

Leishmaniosis (Leishmania infantum infection) and piroplasmoses (Theileria equi and Babesia caballi infections) are vector-borne diseases with significant economic and public health impacts. Despite their importance, there is a lack of data concerning these infections in equids from Tunisia. The present study was carried out to estimate the prevalence of L. infantum, T. equi and B. caballi in 104 equids from northern Tunisia. The authors reported for the first time on the seroprevalence of anti-Leishmania antibodies in equids in Tunisia (6.7%). The study reported a high infection prevalence of piroplasms (23.1%), revealed for the first time T. equi and B. caballi infections in Tunisian donkeys, and showed that these animals act as reservoirs for the maintenance and dissemination of piroplasms.

La leishmaniose (infection à Leishmania infantum) et les piroplasmoses (infections à Theileria equi et à Babesia caballi) sont des maladies à transmission vectorielle dont les conséquences économiques et l'impact sur la santé publique sont significatifs. Malgré leur importance, en Tunisie la situation des équidés vis-à-vis de ces maladies était jusqu'à présent peu documentée. L'étude décrite par les auteurs avait pour objet d'estimer la prévalence des infections à L. infantum, T. equi et B. caballi chez 104 chevaux du Nord de la Tunisie. La recherche d'anticorps dirigés contre Leishmania a permis de déterminer pour la première fois une prévalence sérologique chez les équidés (6,7 %). L'étude a rapporté une prévalence élevée de piroplasmes (23,1 %) et fait état pour la première fois en Tunisie de l'existence d'infections à T. equi et à B. caballi chez des ânes ; elle montre également que ces derniers font office de réservoirs et jouent un rôle dans le maintien et la dissémination des piroplasmes.

La leishmaniosis (infección por Leishmania infantum) y las piroplasmosis (infecciones por Theileria equi y Babesia caballi) son enfermedades transmitidas por vectores que tienen una importante repercusión en la economía y la salud pública. A pesar de su importancia, existen pocos datos sobre estas infecciones en los équidos tunecinos. Los autores describen un estudio destinado a estimar la prevalencia de L. infantum, T. equi y B. caballi en 104 équidos del norte del país, gracias al cual determinaron por primera vez la seroprevalencia de anticuerpos contra Leishmania en équidos tunecinos (un 6,7%). La investigación puso de manifiesto una elevada prevalencia de la infección por piroplasmas (un 23,1%), reveló por vez primera la infección de asnos tunecinos por T. equi y B. caballi y demostró que estos animales ejercen de reservorio, manteniendo y propagando así los piroplasmas.

[Interventional endoscopy in the gastrointestinal tract in children]. / Activité endoscopique digestive interventionnelle chez l'enfant.

BACKGROUND: Interventional endoscopic procedures involving the gastrointestinal (GI) tract in children are very common. Over the last several years the number of procedures in this area has steadily increased. AIM: To study indications and results of GI interventional endoscopies performed in a Pediatric GI unit. METHODS: Retrospective study over a period of 10 years (1999-2008). Data were collected from endoscopic files. All procedures were performed endoscopically under general anesthesia. RESULTS: 185 interventional endoscopic procedures were done during this period in 96 patients (58 boys) median age: 4.9±4.7 years (1 month-13 years). Indications were as follows: esophageal stenosis (n=46; 47.9%), rectal polyp resection (n=21; 19.8%), esophageal varices ligation (n=19; 19.7%), foreign body extractions (n=8; 8.3%) and percutaneous endoscopic gastrostomy (n=2; 2.1%). One hundred and thirteen esophageal dilations (61.1% of procedures) were performed in 46 patients: caustic stenosis (n=22; 22.9%), peptic stenosis (n=13; 13.5%) and anastomotic stenosis (n=11; 11.4%). CONCLUSION: The main indication of interventional GI endoscopy in this series was oesophageal stenosis followed by rectal polyp resection, esophageal varices ligation and foreign body extractions.

Decompositions of the polyhedral product functor with applications to moment-angle complexes and related spaces.

This article gives a natural decomposition of the suspension of a generalized moment-angle complex or partial product space which arises as the polyhedral product functor described below. The introduction and application of the smash product moment-angle complex provides a precise identification of the stable homotopy type of the values of the polyhedral product functor. One direct consequence is an analysis of the associated cohomology. For the special case of the complements of certain subspace arrangements, the geometrical decomposition implies the homological decomposition in earlier work of others as described below. Because the splitting is geometric, an analogous homological decomposition for a generalized moment-angle complex applies for any homology theory. Implied, therefore, is a decomposition for the Stanley-Reisner ring of a finite simplicial complex, and natural generalizations.

Reducing health risks from wastewater use in urban and peri-urban sub-Saharan Africa: applying the 2006 WHO guidelines.

Where rapid urbanization is outpacing urban capacities to provide sound sanitation and wastewater treatment, most water sources in city vicinity are heavily polluted. This is of great concern as many of the leafy vegetables eaten raw in the cities are produced in these areas. Following the new WHO guidelines, different non-treatment options at farm, market, and kitchen level were field tested for health risk reduction with special consideration to efficiency and adoption potential. As most households are used to vegetable washing (although ineffectively), an important entry point for risk reduction is the increased emphasis of the new guidelines on food preparation measures. A combination of safer irrigation practices (water fetching, on-farm treatment, and application), the allocation of farmland with better water sources, and improved vegetable washing in kitchens appear to be able to reduce the potential risk of infections significantly, although it might not be possible to reach the ideal threshold without some kind of wastewater treatment. The on-farm trials carried out in Ghana also explored the limitation of other risk reduction measures, such as drip irrigation, crop restrictions and cessation of irrigation under local circumstances considering possible incentives for behaviour change.

Setting up microbiological water reuse guidelines for the Mediterranean.

Water reuse is a widespread practice in most Mediterranean countries. Some countries have no wastewater treatment facilities and direct reuse of raw wastewater is occurring while others have a well-established national reuse policy. Water reuse microbiological standards, when existing, significantly differ from one country to another. Some countries have adopted regulations close to the California's Water Recycling Criteria whereas other countries have chosen criteria based on the World Health Organisation (WHO) guidelines. California standards are technologically based requirements aimed at eliminating the presence of pathogens. The WHO guidelines relied on epidemiological evidences though few were available. Their revision on the basis of new epidemiological investigations and quantitative microbiological risk assessment (QMRA) provided by Blumenthal et al., together with added QMRA data, helped proposing Mediterranean guidelines. Acceptable annual risks related to bathing and potable water drinking were taken as benchmarks. This proposal is designed to protect individuals against realistic maximum exposures and to provide minimum and affordable requirements which should constitute the basis of water reuse regulations in every country of the region. Inadequacies of the actual knowledge do not allow a definitive position regarding the guideline limits; other scientific and technical basis are still required.

[Posterior radiocarpal fracture-dislocation (eight case reports)]. / Les luxations-fractures radiocarpiennes postérieures (à propos de huit cas).

The Authors report a retrospective series of eight cases of posterior radiocarpal fracture-dislocation. Average age of patients was 32 years (23/54), with a male predominance (7 men and a woman). Injury was often due to a fall on the hand in extension from an elevated place (5/8). The wrist in back of fork is the characteristic deformity. Diagnosis was confirmed by AP and lateral views of the wrist. Radial styloïd fracture, posterior dislocation of the carpus and posterior rim avulsion were constant. Ulnar styloïd fracture was present in half of the cases and distal radio-ulnar dislocation in two cases. Four patients were treated conservatively and four surgically. Whatever the treatment choice, results are satisfactory at a short follow-up. The two patients presenting a distal radio-ulnar dislocation resulted in a bad result.

Reuse of reclaimed wastewater for golf course irrigation in Tunisia.

In Tunisia, golf courses are irrigated with secondary treated effluent stored in landscape impoundments. The impact of the conveyance and storage steps on the physical-chemical and biological quality of irrigation water was evaluated on three golf courses over two years. It was found that the water quality varies all along the water route, from the wastewater treatment plant up to the irrigation site: nutrient and bacteria contents decreased along the route in the three cases. This variation depends on the wastewater quality, the length of the pipes conveying water, the number of regulation reservoirs and ponds, the water residence time in pipes, reservoirs and ponds, and the operation of the ponds. The bacteriological quality of irrigation water deteriorates during the irrigation period in the three golf courses as the ponds are operated as continuous flow reactors. The results obtained in this study indicate the inability of golf water supplies, as currently managed, to properly sanitize reclaimed wastewater and meet target quality criteria recommended by WHO (1989) for water intended for recreational use. For a safe reuse of reclaimed wastewater for golf course irrigation, changes in the design and operation of the ponds should be planned or additional treatment steps provided.

Choosing the pacemaker; a rational approach to the use of modern pacemaker technology.

Sophisticated pacemakers now afford greater benefit than only relief of syncope for patients with symptomatic bradyarrhythmia. For clinical reasons it is inappropriate to implant ventricular demand (VVI) pacemakers in every patient, but for both clinical and economic reasons it is also undesirable to use dual-lead or rate-responsive systems indiscriminately. However, the published guidelines for pacemaker choice and investigation are inadequate. We have analysed the clinical assessment and the investigations required in a series of 150 patients with various electrophysiological disorders, considered consecutively for pacemaker implantation using an algorithm to assist decisions. Holter electrocardiography in 77.3%, exercise testing--formal (in 9.3%) or informal (during Holter electrocardiography), electrophysiology study (EPS)--full in 15.3% and partial in 29.3%, and trial of pacing (10.7%) were all used to characterize dysfunction and to define appropriate pacing mode. 142 patients were paced--57.0% with single lead modes (12.7%) AAI, 44.3% VVI) and 43.0% dual-lead (2.8% DVI, 23.9% VDD or VAT, 16.2% DDD). Three patients received rate-responsive systems (VVIR) which, if available, would have been used in nine; four would have been suitable for AAIR and four for dual-lead responsive pacing (DVIR, DDIR or DDDR). We offer a rational approach based on published data for investigation and pacemaker choice in the management of patients with bradyarrhythmia.

[Ventricular extrasystoles in the convalescence phase of myocardial infarction. Relation to angiographic data]. / Extrasystoles ventriculaires à la phase de convalescence de l'infarctus du myocarde. Relations avec les données angiographiques.

A series of 80 patients hospitalised for recent myocardial infarction underwent: --three continuous ambulatory 24 hour recordings (Holter method) on the 15th, 22nd days, and 6 months after infarction; --selective coronary angiography with left ventriculography, with a study of left ventricular performance and analysis of segmental contractility (Leighton's method). Five patients died over a mean follow-up period of 16 months. At the third week when physical activities were reintroduced 72,3 p. 100 of patients had frequent ventricular extrasystoles (Lown's Class II) or repeated ventricular extrasystoles (Classes III, IV, V). Holter monitoring gave reproducible results with a tendency to aggravation between the Ist and the 6th month (repetitive ventricular activity increasing from 35 to 45 p. 100). 55 p. 100 of posterior infarcts had few extrasystoles whilst 47 p. 100 of anterior infarcts had severe arrhythmias (Classes III, IV and V). There was a significant correlation between the presence of multivessel disease and severe ventricular extrasystoles 60 p. 100 of patients with multiple vessel lesions had repetitive ventricular activity (p less than 0,02). Positive correlations were established between: severe ventricular arrhythmias and a reduction in ventricular ejection fraction (p less than 0,01), dyskinesia in the infarcted zone (p less than 0,01) and reduction in wall motion of the non infarcted zones. The presence of incomplete occlusion of early revascularisation by collateral circulation in the infarcted zone seemed to favour severe ventricular arrhythmias. Five patients died (arrhythmias or cardiac failure): the association of severe hypokinesia and reduced left ventricular performance with repetitive ventricular activity was demonstrated. It is concluded from the correlations obtained between ventriculography and continuous electrocardiographic monitoring that repetitive ventricular activity is associated with severe reduction in left ventricular performance. The immediate gravity and poor prognosis of the ventricular arrhythmias are the result of the extent of the myocardial damage.