Critical review of the trailing edge condition in steady and unsteady flow. Blade flutter in compressors and fans: Numerical simulation of the aerodynamic loading

Existing interpretations of the trailing edge condition, addressing both theoretical and experimental works in steady, as well as unsteady flows are critically reviewed. The work of Kutta and Joukowski on the trailing edge condition in steady flow is reviewed. It is shown that for most practical airfoils and blades (as in the case of most turbomachine blades), this condition is violated due to rounded trailing edges and high frequency effects, the flow dynamics in the trailing edge region being dominated by viscous forces; therefore, any meaningful modelling must include viscous effects. The question of to what extent the trailing edge condition affects acoustic radiation from the edge is raised; it is found that violation of the trailing edge condition leads to significant sound diffraction at the tailing edge, which is related to the problem of noise generation. Finally, various trailing edge conditions in unsteady flow are discussed, with emphasis on high reduced frequencies

Dual mode nanoparticles: CdS coated iron nanoparticles

Reverse micelles can be used in a sequential fashion to make core-shell nanoparticles. Using this technique it is possible to make a magnetic quantum dot, by coating an iron core with a cadmium sulfide shell. Transmission electron microscopy indicated core-shell morphology and narrow size distribution of the obtained particles. Collectively, x-ray powder diffraction and x-ray photoelectron spectroscopy verified the presence of cadmium sulfide on the surface of the nanoparticles. Optical properties of the coated particles were demonstrated using fluorescence spectroscopy. A vibrating sample magnetometer was used to determine magnetic properties. Dual mode cadmium sulfide coatediron core-shell nanoparticles make unique candidates for the use in biomedical applications

Analgesic effect of intra-articular magnesium sulphate compared with bupivacaine after knee arthroscopic menisectomy

AbstractThis work aimed to evaluate the analgesic efficacy of intra-articular injection of magnesium sulphate (4%) compared with equivalent volume of bupivacaine (0.5%) after outpatient knee arthroscopic meniscectomy. Forty patients were randomly assigned to two groups. Group M (n=20) received intra-articular magnesium sulphate 4%, group B (n=20) received bupivacaine (0.5%). Analgesic effect was evaluated by analgesic duration, and by measuring pain intensity at 1, 2, 4, 6, 12, 24h both at rest and on knee movement to 90°. The primary outcome variable was pain intensity on the VAS at 1, 2, 4, 6, 12, 24h post arthroscopy at rest and on movement (flexion of knee to 90°), although the magnesium group had lower time weighted averages (TWAs) at rest and on movement, these TWAs were not statistically significant. The median duration of postoperative analgesia was significantly longer in the patients treated with magnesium sulphate (528min) than in the bupivacaine group (317min) (p<0.0001), with less number of patients needing supplementary analgesia in magnesium group (8/20) than those of the bupivacaine group (16/20) (p<0.022). Also analgesic consumption was significantly lower in the magnesium sulphate group (p<0.002). We concluded that the use of magnesium sulphate is rational and effective in reducing pain, and is more physiological and shortens convalescence after outpatient arthroscopic meniscectomy, however our hypotheses that analgesic efficacy of intra-articular isotonic magnesium sulphate would be superior to intra-articular local anaesthetic cannot be supported with this study

Lactatemia during treatment of status asthmaticus in children

Background: Transient increase of lactate levels with or without metabolic acidosis has been seldom reported as a complication of β2-adrenergic therapy administered during asthma attacks in children. Objective: The study is aimed to investigate the frequency of lactatemia in children with acute asthma treated with nebulized β2-agonists, and to delineate its causes and effects on prognosis. Methods: We studied 32 asthmatic children; 68.8% had intermittent asthma, and 31.2% had mild persistent asthma. Their ages ranged from 6 to 8 years with a mean of 6.48±0.68 years. Patients were enrolled during acute asthma exacerbation (62.5% had severe and 37.5% had moderate attacks)from the Cairo University Children's Hospital. Patients underwent clinical evaluation, and routine investigations (CBC, PEFR, and total serum IgE) then received nebulized salbutamol at 0.1 mg/kg/dose (minimum 2.5 mg) every 20 min for three doses together with O2. Plasma lactate was determined before, 1 h after, and 24 h following the inhalation therapy. Blood gases were also evaluated before and after the β2-agonist treatment. Results: At 1 h post-treatment, all patients had appreciable lactatemia (4.44±0.78 mmol/L, p &lt; 0.001) compared to the pre-treatment level with a rise of 257±121.5%. Patients with severe attacks demonstrated a higher mean value compared to those with moderate attacks (4.69±0.8 mmol/L versus 4.02±0.6 mmol/L, p &lt; 0.05). At 24 h post-treatment, lactate levels returned to the normal values in most patients (1.91±0.59 mmol/L, p &lt; 0.001) as compared to the 1 h post-treatment level. None of our patients developed metabolic acidosis and all of them showed significant clinical improvement. Our results strongly accuse nebulized salbutamol as the possible pathogenetic factor for lactatemia during therapy of acute asthma attacks, while overworked respiratory muscles and hypoxemia have been excluded as contributing factors. Conclusion: Transient lactatemia is not uncommon during β2-agonist therapy in asthmatic children with acute exacerbation, and is harmless in most cases. Prediction of lactic acidosis prevents inappropriate intensification of therapy especially in patients with more severe attacks or impending respiratory failure.Keywords: Asthma, exacerbation, lactate, lactatemia, β2-agonist, salbutamolEgypt J Pediatr Allergy Immunol 2004; 2(2): 83-8

Stress-induced changes in the aged-rat adrenal cortex. Histological and histomorphometric study

Background: Stress exposure exerts direct effects on the morphology and functionality of the adrenal cortex. In addition, ageing effects growth, differentiation, apoptosis and cellularity of the cortex. The missing data is the combined effect of stress and ageing on the adrenal cortex. The aim of this study was to demonstrate the structural changes in the adrenal cortex following the exposure to stress in the adult and aged albino rats.   Materials and methods: Forty rats were divided into groups I and II (adult and senile). Each group was further subdivided into subgroups a and b (control and stressed). Light and electron microscopic studies were done. Area per cent of collagen fibres (Masson’s trichrome-stained sections), number of proliferating cells (optical density immunoreactivity in the Ki67 stained sections) and thickness of the three adrenal zones were also measured.   Results: Lamellar separation of the capsule with subcapsular spindle cell hyperplasia and areas of ghost cells were observed in zona glomerulosa (ZG) and zona fasciculata (ZF) in group I-b. Separation and indentation of the capsule with its lamellar separation were observed in group II-a with the existence of multiple scattered degenerative foci in ZF and zona reticularis (ZR). Similar and aggressive was the architectural pattern of ZF in group II-b with the presence of areas of homogenous degeneration. The nuclei of ZG had marginated chromatin in group I-b and were pyknotic with deformed irregular outlines in group II-b. Multiple lysosomes and vacuolar degeneration mitochondria were also seen in group I-b. The nuclei of ZF were irregular with condensed marginated heterochromatin in group I-b, irregular with scattered chromatin in group II-a and indented with areas of chromatin destruction in group II-b. Mitochondria with disrupted cristae and cristolysis were also detected in group I-b. Numerous lipofuscin granules and dilated smooth endoplasmic reticulum were revealed in group II-b. The mean collagen fibre area per cent and the mean number of the proliferating cells in group II-b were significantly higher by 39% and 23%. The thickness of ZG decreased significantly by 20% in group I-b. Contrary, the thickness of both ZF and ZR increased significantly by 10% in group I-b.   Conclusions: Histological alterations occurred in the adrenal cortex in response to stress, especially when coupled with the advance of age. This was accompanied by increase in the area per cent of collagen fibres and increase in the mean number of the proliferating cells in the adrenal cortex

HLA Class II Defects in Burkitt Lymphoma: Bryostatin-1-Induced 17 kDa Protein Restores CD4+ T-Cell Recognition

While the defects in HLA class I-mediated Ag presentation by Burkitt lymphoma (BL) have been well documented, CD4+ T-cells are also poorly stimulated by HLA class II Ag presentation, and the reasons underlying this defect(s) have not yet been fully resolved. Here, we show that BL cells are deficient in their ability to optimally stimulate CD4+ T cells via the HLA class II pathway. The observed defect was not associated with low levels of BL-expressed costimulatory molecules, as addition of external co-stimulation failed to result in BL-mediated CD4+ T-cell activation. We further demonstrate that BL cells express the components of the class II pathway, and the defect was not caused by faulty Ag/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Treatment of BL with broystatin-1, a potent modulator of protein kinase C, led to significant improvement of functional class II Ag presentation in BL. The restoration of immune recognition appeared to be linked with an increased expression of a 17 kDa peptidylprolyl-like protein. These results demonstrate the presence of a specific defect in HLA class II-mediated Ag presentation in BL and reveal that treatment with bryostatin-1 could lead to enhanced immunogenicity

Comprehensive evaluation of the association of APOE genetic variation with plasma lipoprotein traits in U.S. Whites and African Blacks

Although common APOE genetic variation has a major influence on plasma LDL-cholesterol, its role in affecting HDL-cholesterol and triglycerides is not well established. Recent genome-wide association studies suggest that APOE also affects plasma variation in HDL-cholesterol and triglycerides. It is thus important to resequence the APOE gene to identify both common and uncommon variants that affect plasma lipid profile. Here, we have sequenced the APOE gene in 190 subjects with extreme HDL-cholesterol levels selected from two well-defined epidemiological samples of U.S. non-Hispanic Whites (NHWs) and African Blacks followed by genotyping of identified variants in the entire datasets (623 NHWs, 788 African Blacks) and association analyses with major lipid traits. We identified a total of 40 sequence variants, of which 10 are novel. A total of 32 variants, including common tagSNPs (≥5% frequency) and all uncommon variants (<5% frequency) were successfully genotyped and considered for genotype-phenotype associations. Other than the established associations of APOE∗2 and APOE∗4 with LDL-cholesterol, we have identified additional independent associations with LDL-cholesterol. We have also identified multiple associations of uncommon and common APOE variants with HDL-cholesterol and triglycerides. Our comprehensive sequencing and genotype-phenotype analyses indicate that APOE genetic variation impacts HDL-cholesterol and triglycerides in addition to affecting LDL-cholesterol

Laparoscopic sacrohysteropexy and myomectomy for uterine prolapse: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>A large number of hysterectomies are carried out for uterine prolapse, menorrhagia and other symptomatic but benign gynaecological conditions, which has increased interest in new approaches to treat these disorders. These new procedures are less invasive and offer reduced risk and faster recovery.</p> <p>Case presentation</p> <p>Sacrohysteropexy can be carried out instead of vaginal hysterectomy in the treatment of uterine prolapse. It involves using a synthetic mesh to suspend the uterus to the sacrum; this maintains durable anatomic restoration, normal vaginal axis and sexual function. A laparoscopic approach has major advantages over the abdominal route including shorter recovery time and less adhesion formation. We describe a laparoscopic sacrohysteropexy in a 55-year-old Caucasian British woman that was technically difficult. An intramural uterine fibroid was encroaching just above the uterosacral ligament making mesh positioning impossible. This was removed and the procedure completed successfully.</p> <p>Conclusion</p> <p>Posterior wall fibroid is not a contraindication for laparoscopic sacrohysteropexy. This procedure has increasingly become an effective treatment of uterine prolapse in women who have no indication for hysterectomy.</p