Angiotensin II blockade and aortic-root dilation in Marfan's syndrome

Background: Progressive enlargement of the aortic root, leading to dissection, is the main cause of premature death in patients with Marfan's syndrome. Recent data from mouse models of Marfan's syndrome suggest that aortic-root enlargement is caused by excessive signaling by transforming growth factor (beta) (TGF-(beta)) that can be mitigated by treatment with TGF-(beta) antagonists, including angiotensin II-receptor blockers (ARBs). We evaluated the clinical response to ARBs in pediatric patients with Marfan's syndrome who had severe aortic-root enlargement. Methods: We identified 18 pediatric patients with Marfan's syndrome who had been followed during 12 to 47 months of therapy with ARBs after other medical therapy had failed to prevent progressive aortic-root enlargement. The ARB was losartan in 17 patients and irbesartan in 1 patient. We evaluated the efficacy of ARB therapy by comparing the rates of change in aortic-root diameter before and after the initiation of treatment with ARBs. Results: The mean (+/-SD) rate of change in aortic-root diameter decreased significantly from 3.54+/-2.87 mm per year during previous medical therapy to 0.46+/-0.62 mm per year during ARB therapy (P<0.001). The deviation of aortic-root enlargement from normal, as expressed by the rate of change in z scores, was reduced by a mean difference of 1.47 z scores per year (95% confidence interval, 0.70 to 2.24; P<0.001) after the initiation of ARB therapy. The sinotubular junction, which is prone to dilation in Marfan's syndrome as well, also showed a reduced rate of change in diameter during ARB therapy (P<0.05), whereas the distal ascending aorta, which does not normally become dilated in Marfan's syndrome, was not affected by ARB therapy. Conclusions: In a small cohort study, the use of ARB therapy in patients with Marfan's syndrome significantly slowed the rate of progressive aortic-root dilation. These findings require confirmation in a randomized trial

Finite element modeling of nonequilibrium fluid-wall interaction at high-Mach regime

The numerical modeling of the aerodynamic interactions at high-Altitudes and high-Mach numbers is considered in view of its importance when studying problems where the continuum hypothesis at the foundation of the Navier- Stokes equations becomes invalid. One of the difficulties associated with these flight conditions is that both the velocity and the temperature of the fluid do not abide by the no-slip conditions at the wall. A weak Galerkin finite element formulation of the Maxwell-Smoluchowki model is introduced to discretize the velocity slip and temperature jump conditions with better accuracy than the standard finite element approximation. The methodology is assessed on configurations such as cylinders and spheres for flow conditions ranging from quasi-equilibrium to nonequilibrium. Improvements are observed in the slip regime compared with available data. Nonetheless, the results in the transition regime highlight the need for more sophisticated physical modeling to address nonequilibrium at the wall

Potentially toxic elements in saltmarsh sediments and common reed (Phragmites australis) of Burullus coastal lagoon at North Nile Delta, Egypt: A survey and risk assessment

Burullus lagoon is the second largest lake in Egypt. However, there has never been a comprehensive survey which studied nineteen potentially toxic elements in sediments and plants and evaluated the associated potential risk. Thus, we aimed to study the total and potentially available content of As, Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Sb, Se, Sn, Tl, V, and Zn in the sediments and common reed (Phragmites australis) at thirty two sites along the entire lagoon and connected drains. Contamination Factor (CF), Pollution Load Index (PLI), Geo-accumulation Index (Igeo), and Enrichment Factor (EF) were calculated to assess the grade of contamination. Element accumulation factor (AF) and bio-concentration ratio (BCR) were also calculated. Aluminum showed the highest median (mg kg−1) total content (41,200), followed by Fe (30,300), Mn (704.7), V (82.0), Zn (75.5), Cr (51.2), Cu (47.8), Ni (44.3), As (31.9), Tl (24.6), Co (21.4), Se (20.3), Sb (17.6), Sn (15.6), Mo (11.3), and Hg (16.6 μg kg−1). Values of the EF, CF, and Igeo showed that the sediments were heavily contaminated with As, Sb, Se, Tl, Mo, Sn, Co, Ni, and Cu. The drained sediment had significantly higher values of total and potentially available element content than the lagoon sediments. Sediments of the middle and western area showed significantly higher contents of total and available elements than the eastern section. The BCR and AF values indicate that the studied plant is efficient in taking up high amounts of Zn, Fe, As, Sn, Tl, Ni, Mo, Mn; then Co, Cu, and V. The results exhibit a dramatic contamination at certain sites of the lagoon, and the studied PTEs have a predominant role in contamination-related ecological risk. Further investigations concerning redox-induced mobilization of PTEs in sediments, the risk of fish contamination and the potential health hazards are highly recommended

Seasonal variation in the characteristics of the Azarbaijani buffalo (Bubalus bubalis) semen

Summary To study the seasonal variation in the characteristics of the Azarbaijani buffalo semen, three 2-4-year-old bulls of Azarbaijani water buffaloes, kept in the Buffalo Breeding Center, in Urmia, northwest of Iran, were selected. Semen samples were collected once a week for a period of one year using artificial vagina and a buffalo cow as a dummy. Semen volume, colour, pH and motility and spermatozoa motility, viability, morphology and concentration were examined. During one calendar year, 129 semen samples were examined. The mean values were plotted and a curve was drawn for the annual variations in each parameter. The comparison of the mean values in each sampling and in different seasons and the correlation between these variations and ecological factors, such as temperature, rainfall and day length were also studied. Semen was characterized by a mean (±SEM) ejaculation volume of 4 ± 0.14 ml, semen colour density score of 3.75 ± 0.07, pH of 6.97 ± 0.03 and motility score of 2.89 ± 0.05. The sperm motility of 75.85% ± 1.59% and sperm viability of 73.2% ± 1.56% were observed; 11.55% ± 0.42% of spermatozoa had abnoraml morphology. The mean (±SEM) sperm concentration was 1239.9 ± 34.11×10 6 cells/ml. All of the studied parameters showed fluctuations throughout the year but these variations were statistically significant only in some occasions and were mostly correlated with length of the day. Semen of better quality was collected in summer and autumn

Finite-element formulation of a Jacobian-free solver for supersonic viscous flows on hybrid grids

A parallel Jacobian-free solver for supersonic flows on unstructured hybrid meshes is proposed. An edge-based Finite Element formulation is used for spatial discretization with flow stabilized via either AUSM+-up or a Roe scheme. The Jacobian-free Newton-Krylov method is used as linear system solver and the lower-upper symmetric Gauss-Seidel method is used for matrix-free preconditioning. In the present formulation, second order approximations of spatial derivatives of the inviscid fluxes are introduced efficiently. Numerical results for Mach 1.93 flow past a sphere, Mach 4 flow past a waverider, and Mach 10.01 flow past a sphere, are presented

A comprehensive review of oral glucosamine use and effects on glucose metabolism in normal and diabetic individuals

Glucosamine (GlcN) is a widely utilized dietary supplement that is used to promote joint health. Reports that oral GlcN supplementation at usual doses adversely affects glucose metabolism in subjects with impaired glucose tolerance have raised concerns that GlcN should be contraindicated in individuals with diabetes and those at risk for developing it. This review addresses its potential, when used at typical doses, to affect glucose metabolism and insulin sensitivity in healthy individuals and those with diabetes or ‘pre-diabetes’. Publicly available scientific information and data on GlcN were systematically compiled using the electronic search tool, Dialog®, and reviewed with special emphasis on human studies. In long-term clinical trials, including those containing subjects with type 2 diabetes or ‘pre-diabetes’, GlcN produced a non-significant lowering of fasting blood glucose concentrations in all groups of subjects treated for periods of up to 3 years. Owing to limitations in study design, conclusions based on studies that report adverse affects of GlcN on insulin sensitivity and glucose tolerance in pre-diabetic subjects are suspect. However, no definitive long-term studies of GlcN use for individuals with pre-diabetes are available. Nevertheless, based on available evidence, we conclude that GlcN has no effect on fasting blood glucose levels, glucose metabolism, or insulin sensitivity at any oral dose level in healthy subjects, individuals with diabetes, or those with impaired glucose tolerance

Reclamation of reactive metal oxides from complex minerals using alkali roasting and leaching- an improved approach to process engineering

In nature, the commonly occurring reactive metal oxides of titanium, chromium, aluminium, and vanadium often chemically combine with the transition metal oxides such as iron oxides and form complex minerals. Physico-chemical separation of transition metal oxides from the remaining reactive metal oxides is therefore an important step in the purification of reactive oxide constituents. Each purification step has quite a high energy requirement at present. Current practice in industry yields sulphate and neutralized chloride waste from titanium dioxide enrichment, red mud from bauxite refining, slag and leach residues from vanadium extraction and chromite ore process residue (COPR) from chromate processes. In this review article, a novel alkali-based oxidative roasting and aqueous leaching for the extraction of mineral oxides is explained in the context of the original work of Le Chatelier in 1850, which was unsuccessful in the industrialization of bauxite processing for alumina extraction. However, much later in the 19th century the alkali-based oxidative mineral roasting was successfully developed for industrial scale manufacturing of chromate chemicals, which yields COPR. The crystal chemistry of mineral oxides, namely alumina, titanium dioxide, and chromium oxide in naturally occurring minerals is briefly reviewed in the context of chemical extraction, which is then developed as a model for developing thermodynamic chemical equilibrium principles for analyzing the physical separation and enrichment of such reactive metal oxides by forming water-soluble and water-insoluble alkali complexes. The involvement of the alkali roasting chemistry of non-magnetic titaniferous mineral waste is also reported in the initial separation of rare-earth oxide mixtures for subsequent separation of individual oxides. The paper concludes with a generic approach to process chemistry which minimizes waste generation and therefore helps in reducing the overall process and energy costs. Examples of recovering alkali from high pH solution using carbon dioxide are also demonstrated

From absent to present pasts: civil society, democracy and the shifting place of memory in Brazil

This paper takes Alexis de Tocqueville’s concern with the emotional life of citizens as a cue for exploring the role of collective memory within ‘the self-organizing sphere’ and asking how the invocation of memory affects progress towards democracy. The paper hones in on the Brazilian experience, re-assessing Brazil’s amnesiac past as well as its much lauded ‘turn to memory’. Against common assertions that Brazil’s ‘turn to memory’ will enhance the country’s democratic credentials, this paper argues that the move from an ‘absent’ to a ‘present’ past in Brazil in fact bodes rather mixed prospects for the country’s democratic deepening