Mechanical property evaluation of an Al-2024 alloy subjected to HPT processing

An aluminum-copper alloy (Al-2024) was successfully subjected to high-pressure torsion (HPT) up to five turns at room temperature under an applied pressure of 6.0 GPa. The Al-2024 alloy is used as a fuselage structural material in the aerospace sector. Mechanical properties of the HPT-processed Al-2024 alloy were evaluated using the automated ball indentation technique. This test is based on multiple cycles of loading and unloading where a spherical indenter is used. After two and five turns of HPT, the Al-2024 alloy exhibited a UTS value of ~1014 MPa and ~1160 MPa respectively, at the edge of the samples. The microhardness was measured from edges to centers for all HPT samples. These results clearly demonstrate that processing by HPT gives a very significant increase in tensile properties and the microhardness values increase symmetrically from the centers to the edges. Following HPT, TEM examination of the five-turn HPT sample revealed the formation of high-angle grain boundaries and a large dislocation density with a reduced average grain size of ~80 nm. These results also demonstrate that high-pressure torsion is a processing tool for developing nanostructures in the Al-2024 alloy with enhanced mechanical propertie

Preliminary phytochemical constituents and phytotoxic effect of Albizia lebbeck (L.) Benth on Sorghum bicolor

The preliminary Phytochemical investigations and phytotoxic effects of aqueous leaf extracts of Albizia lebbeck on Sorghum bicolor was assessed. The result from phytochemical screening revealed that all the allelochemicals tested where found present except steroids and phlobatannins when petroleum ether, methanol and water extracts were used. Petroleum ether extract show the presence of amino acids, protein and glycosides while methanol and water extracts showed their absence. Alkaloids, anthraquinones and acids were found present when methanol was used and absent using petroleum ether and water extracts. These allelochemicals are all important allelopathic sources. The leaf extract slowed down the rate of growth of the radicle and plumule of Sorghum bicolor seeds when compared to control. But these inhibitions were not significantly different at 5% level. The degree of inhibition increased with increase of concentration of the extracts hence inhibitions were prominent at extract of higher concentrations.Keywords: Phytochemical constituents, Phytotoxic effects, Albizia lebbeck, Sorghum bicolo

Clinicopathological Effects of Oral Administration of Ethanol Leaf Extract of Charcoal–Tree (Trema Orientalis Linn Blume) in Jamnapari Crossbred Goats

The present study was aimed at evaluating the clinicopathological changes due to oral administration of ethanol leaf extract of Trema orientalis (ELETO) in Jamnapari crossbred goats. The clinical manifestations, gross and histopathological changes in the major vital organs were used as indices of the toxicity. The severity of gross and microscopic changes were evaluated by scoring technique. Twenty goats weighing between 15-20kg were divided into four groups with five goats in each group in a completely randomized design. The test groups I, II, III were administered ELETO at the dosages of 0.5, 1.0 and 2.0g/kg b.wt per os/day respectively, for 14 days while, group IV served as a control. Groups II and III showed decreased appetite whereas, group III showed bilateral congestion of ocular mucous membrane, lacrimation, rectal tenesmus and a significant decrease in body weight compared to control. The main gross and microscopic changes were mild to moderate and included; engorgement of the gall bladder, congestion and icteric liver, hepatocellular degeneration, vacuolation, necrosis and renal congestion observed mainly in group III goats. The results indicate that the ELETO was hepatotoxic and nephrotoxic at continued oral doses equal to or more than 2.0g/kg b.wt in goats but no significant toxicity when used at lowers doses. Therefore, special caution should be taken when keeping goats in areas with T. orientalis. Keywords: Ethanol extract, Trema orientalis, Clinicopathological changes, Goats

Pattern of serum zinc level, peripheral blood lymphocyte and neutrophil counts among patients with sickle cell disease

Background: Zinc is an important mineral element serving as a cofactor in a number of cellular pathways including those involved in cell growth and proliferation. Sickle cell disease (SCD) is associated with excessive haemolysis and defective kidney function with consequential decrease in body’s pool of vital micronutrients. The abnormal loss of zinc in SCD may affect leucopoiesis. Aim: This study was aimed to determine the relationship between serum zinc and leukocyte subsets (Lymphocyte, neutrophil) in adult patients with SCD in steady state together with their counterpart apparently healthy controls. Materials and Methods: Blood samples were collected from 33 adult participants with SCD and 33 apparently healthy controls. Lymphocytes and Neutrophils counts were performed using automated haematology analyser (Sysmex KX21N) and serum Zinc level was determined spectrophometrically using the Br-PADAP method. Results: The results shows statistically significant difference in absolute lymphocyte and neutrophil counts for the two groups were P < 0.0001 and P < 0.0001, respectively. The serum zinc level was also statistically significant between the groups: P<0.0002. However, serum zinc level of subjects with SCD showed no correlation with lymphocyte and neutrophil counts p<0.0610 and <0.6775, respectively. Conclusions: Significant statistical difference was observed, indicating SCD patients have higher WBC count and neutrophil counts and reduced serum zinc and lymphocyte counts. There was no significant correlation between the leucocyte subset counts and serum zinc levels in both the SCD patients and the normal healthy controls. Keywords: Sickle Cell Disease; Lymphocytes; Neutrophils and Zinc

Salt domes of the United Arab Emirates: evidence for late Neoproterozoic sedimentation and rift volcanism in the northern Arabian-Nubian Shield

Seven of the nine emergent salt domes of the UAE have been examined. They outcrop on the Arabian Gulf islands of Delma, Sir Bani Yas, Arzana, Qarnain, Zirku and Sir Bu N’Air, with one on-land salt dome at Jebal Dhanna. The salt domes range from about 1 km across (incomplete remnant of Qarnain) to over 6 km diameter (Delma) and form dissected hilly topography rising to about 140 m above sea-level (Zirku). The majority of the salt domes are single intrusions but two, Delma and Jebal Dhanna, appear to have multiple phases. The diapirs were emplaced penecontemporaneously with the Miocene country rocks, while evidence of recent localised halokinetic reactivation in small dome-like “salt blisters” is seen on a number of salt islands

Taphonomic and zooarchaeological investigations at the middle Pleistocene site of Ti's al Ghadah, western Nefud Desert, Saudi Arabia

In recent years, the Arabian Peninsula has emerged as a key region for elucidating hominin and faunal evolution and dispersals between Africa and Eurasia. Central to this research is the middle Pleistocene site of Ti's al Ghadah (TAG) which has yielded a diverse and abundant fossil faunal assemblage and the earliest chronometrically dated evidence for hominins in this part of the world. Here, we present the first detailed taphonomic study of the large Unit 5 fossil assemblage from the site. We aim to assess which actor/s were responsible for the accumulation of the assemblage and evaluate evidence that might be consistent with the accumulation of fauna by hominins. We also describe, for the first time, fossils and lithic artefacts from stratigraphic horizons not previously considered, providing taphonomic insights into their accumulation. The taphonomic work shows that the Unit 5 faunal assemblage was accumulated by ambush predators, likely large felids and hominins, in a lake side environment, and that carcasses were subsequently scavenged by more durophagus carnivores such as hyenas and canids. Less can be reliably said regarding the newly described fossil assemblages given their poor preservation and significant wind abrasion, but large carnivores again appear to have played a role, and hominins probably played a role in the accumulation of at least one of these. This study provides the first detail insights into the interplay between hominins, carnivores, and herbivores in Arabia, and suggests that watering holes have been a focus on the Arabian landscape for resources since the middle Pleistocene

Vitamin D deficiency and insufficiency in Africa and the Middle East, despite year-round sunny days

Exposure to sunlight, specifically ultraviolet B (UVB), is essential for cutaneous vitamin D synthesis. Despite significant daily sunlight availability in Africa and the Middle East, persons living in these regions are frequently vitamin D insufficient or deficient. Vitamin D insufficiency (25-hydroxyvitamin D (25(OH)D) between 15 and 20 ng/mL (37.5 - 50 nmol/L)) has been described in various population groups, ranging from 5% to 80%. Risk factors include traditional dress and avoidance of sunlight exposure, and multiple dietary factors as a result of specific cultural beliefs. Vitamin D resistance due to calcium deficiency mechanisms has been described in similar population groups, which may lead to hypovitaminosis D. Should the new diseases related to hypovitaminosis D prove to be truly associated, Africa and the Middle East will become an epicentre for many of these conditions. Urgent attention will need to be paid to cultural dress and dietary behaviours if hypovitaminosis D is to be taken seriously. Should such factors not be correctable, new strategies for supplementation or food fortification will have to be devised.http://www.samj.org.zaam201

Radioimmunotherapy of B-cell lymphoma with radiolabelled anti-CD20 monoclonal antibodies

CD20 has proven to be an excellent target for the treatment of B-cell lymphoma, first for the chimeric monoclonal antibody rituximab (Rituxan™), and more recently for the radiolabelled antibodies Y-90 ibritumomab tiuxetan (Zevalin™) and I-131 tositumomab (Bexxar™). Radiation therapy effects are due to beta emissions with path lengths of 1–5 mm; gamma radiation emitted by I-131 is the only radiation safety issue for either product. Dose-limiting toxicity for both radiolabelled antibodies is reversible bone marrow suppression. They produce response rates of 70%–90% in low-grade and follicular lymphoma and 40%–50% in transformed low-grade or intermediate-grade lymphomas. Both products produce higher response rates than related unlabelled antibodies, and both are highly active in patients who are relatively resistant to rituximab-based therapy. Median duration of response to a single course of treatment is about 1 year with complete remission rates that last 2 years or longer in about 25% of patients. Clinical trials suggest that anti- CD20 radioimmunotherapy is superior to total body irradiation in patients undergoing stem cell supported therapy for B-cell lymphoma, and that it is a safe and efficacious modality when used as consolidation therapy following chemotherapy. Among cytotoxic treatment options, current evidence suggests that one course of anti-CD20 radioimmunotherapy is as efficacious as six to eight cycles of combination chemotherapy. A major question that persists is how effective these agents are in the setting of rituximab- refractory lymphoma. These products have been underutilised because of the complexity of treatment coordination and concerns regarding reimbursement