Implicit geometric representation of gas turbine blades for optimal shape design

This work is concerned with the development and integration of two geometric representations of turbine blade profiles that are appropriate for aerodynamic optimization. The first model is the Modified Rapid Axial Turbine Design (MRATD) model where the blade is represented by five low-order curves that satisfy fifteen designer parameters; this model is suitable for a global search of the design space. The second model is based on a Non-Uniform Rational B-Spline (NURBS) parametrization that implicitly represents the MRATD profile and the implied designer parameters; this model can be used for a local shape refinement. The two models are presented and are assessed for flexibility, accuracy and curve smoothness when representing several typical turbine blade profiles. The models are also assessed in terms of their effect on the blades aerodynamic performance as measured by the pressure distribution along the blade surfaces. The usefulness of the MRATD model is demonstrated in the global shape optimization of a subsonic cascade. The NURBS parametrization provides a means to control the blade profile locally, e.g., the blade curvature near a point smoothened by adjusting the NURBS control points and corresponding weights defining the given region. Finally, a 3D blade design model that uses the NURBS skinning technique is developed and assessed in terms of its precision and smoothness. This 3D model sets the foundation towards developing a robust scheme for 3D aerodynamic optimization

Analysis of RC Continuous Beams Strengthened with FRP Plates: A Finite Element Model

Strengthening of reinforced concrete (RC) beams with externally bonded fibre reinforced polymer (FRP) plates/sheets technique has become widespread in the last two decades. Although a great deal of research has been conducted on simply supported RC beams, a few studies have been carried out on continuous beams strengthened with FRP composites.  This paper presents a simple uniaxial nonlinear finite-element model (UNFEM) that is able to accurately estimate the load-carrying capacity and the behaviour of RC continuous beams flexurally strengthened with externally bonded FRP plates on both of the upper and lower fibres. A 21-degree of freedom element is proposed with layer-discretization of the cross-sections for finite element (FE) modelling. Realistic nonlinear constitutive relations are employed to describe the stress-strain behaviour of each component of the strengthened beam. The FE model is based on nonlinear fracture mechanics. The interfacial shear and normal stresses in the adhesive layer are presented using an analytical uncoupled cohesive zone model with a mixed-mode fracture criterion. The results of the proposed FE model are verified by comparison with various selected experimental measurements available in the literature. The numerical results of the plated beams (beams strengthened with FRP plates) agreed very well with the experimental results. The use of FRP increased the ultimate load capacity up to 100 % compared with the non-strengthened beams as occurred in series (S). The major objective of the current model is to help engineers’ model FRP-strengthened RC continuous beams in a simple manner

Analysis of Opioid Prescription Patterns and Postoperative Opioid Use in Opioid-Naïve Patients Undergoing Elective Lumbar Spine Surgery

Title: Analysis of Opioid Prescription Patterns and Postoperative Opioid Use in Opioid-Naïve Patients Undergoing Elective Lumbar Spine Surgery Background: Post-operative opioid prescribing patterns after elective spine surgery is a growing topic of concern, as over-prescribing can lead to potential medication dependence, while under-prescribing can lead to inadequate pain management. Objective: The primary objective was to develop prescribing guidelines based upon the amount of opioids used in the first 2 weeks after lumbar spine surgery by 80% of patients. Methods: Utilizing a prospective study design, opioid-naïve patients undergoing elective lumbar spine surgery at our institution were identified each week and preoperatively consented for study participation. Opioid naivete was defined as lack of opioid use at least 1 month prior to the scheduled surgical procedure. At 2 weeks postoperatively, enrolled patients completed a telephone survey questionnaire, which assessed remaining opioid prescription pill count, need for medication refill, and subjective patient satisfaction with opioid dosing. Subsequently, patient charts were retrospectively reviewed for patient demographic and medical co-morbidity data. Univariate two group comparisons were performed using t-tests for continuous variables, and using chi-square, or Fisher’s tests if cell counts are \u3c5 for categorical variables. We then looked at the distribution of MMEs in each cohort in order to determine the opioid needs of 80% of the patient population. Results: A total of 53 opioid-naïve spine surgery patients were included for analysis, of which 23 underwent fusion surgery and 30 underwent non-fusion surgery. Baseline demographics and co-morbidities did not significantly vary between groups. For the fusion group, analysis revealed that an MME of 90 would meet the opioid requirements for 80% of patients. In this group, 60% of fusion patients were under-prescribed opioids, while 27% of patients were over-prescribed. For the non-fusion group, an MME of 45 was determined to meet the opioid requirements of 80% of patients. In this group, 61% of non-fusion patients were overprescribed opioids, while 22% were under prescribed. Conclusions: Amongst opioid-naïve patients who underwent elective lumber spine surgery, patients in the lumbar fusion group were generally under-prescribed postoperative opioids, while patients in the non-fusion groups were over-prescribed. This discrepancy suggests that spine surgeons must account for the procedure type (i.e., fusion vs non-fusion) when prescribing opiates postoperatively in opioid-naïve patients, given patients undergoing lumbar fusion may require a larger MME than non-fusion patients. Keywords: opioid-naïve; lumbar spine surgery; fusion; postoperative opioid use; MM

Serum YKL-40 and assessment of severity of bronchial asthma in Egyptian children

Background: Serum and lung tissue levels of a chitinase-like protein YKL-40 have recently been found to be increased in patients with bronchial asthma. Furthermore, serum YKL-40 levels correlated positively with thickening of the lung sub-epithelial basement membrane, frequency of rescue inhaler use, and deterioration in pulmonary function in European asthmatic subjects. Objectives: to assess the role of YKL-40 measurement in evaluating asthma severity, compared to clinical assessment and the related pulmonary function tests. Methods: We quantified serum YKL-40 levels in two groups of Egyptian asthmatics: One group with mild to moderate asthma, and one with severe asthma. Serum YKL-40 was measured by enzyme-linked immunosorbent assay (ELISA) kits (Quidel). Clinical scoring of asthma severity by Pediatric Asthma Score (PAS) and pulmonary functions were performed. Results: The serum levels of YKL-40 were significantly elevated in severely asthmatic Egyptian children compared with the other group (151ng/ml- 72ng/ml; p < 05). YKL-40 levels were correlated positively to PAS (r=0.34, p < 0.05), and inversely to FEV1 (r= -0.32, p < 0.5). Best cut off value of YKL-40 for asthma prognosis was 90 ng/ml, sensitivity 86.5%, specificity 81%, and diagnostic accuracy of 85%. Conclusions: YKL-40 is found in increased quantities in the sera of severe asthmatics, and correlated significantly to PAS and pulmonary function deterioration. YKL-40 is considered a promising biomarker for asthma severity and pulmonary remodeling warranting further study as a potential novel pathway to disease management. Keywords: YKL-40, Asthma, severity, Egyptian, Children, biomarkerEgypt J Pediatr Allergy Immunol 2011;9(2):93-9

Immunological role of nasal staphylococcus aureus carriage in patients with persistent allergic rhinitis

Nasal carriage of staphylococcus aureus (S.aureus) exerts immunomodulatory effect in patients with atopic dermatitis and it may contribute to airway inflammation and allergic response in patients with allergic rhinitis. We Aim to investigate the frequency of nasal S.aureus carriage in patients with persistent allergic rhinitis and its possible influence on their symptoms and immune markers. We chosed 20 non smoker patients with house dust mite (HDM) allergy causing allergic rhinitis and 20 non smoker healthy subjects matched for age and sex. For all subjects rhinoscopy was done, skin prick test, nasal culture for S.aureus, nasal interleukin 4,nasal total IgE, serum total IgE and serum specific IgE(SSIgE) for HDM. Nasal S.aureus was detected in 16/20 patients (80%) and 5/20 (25%) in healthy subjects with highly significant statistical difference p<0.01. Correlation of nasal staph.aureus count and different systemic and local immune markers revealed highly significant positive correlation between nasal S.aureus count and serum total IgE (r = 0.78, p<0.01) and significant positive correlation with SSIgE (HDM) (r = 0.53, p<0.05), nasal total IgE (r = 0.39, p<0.05) and nasal IL-4 (r = 0.55, p<0.05). Nasal staph.aureus actively modulated the immune reaction in persistent allergic rhinitis patients by promoting local IgE production, so we recommend early detection and treatment of S.aureus carriage in patients

Study of Treg FOXP3 in childhood bronchial asthma in relation to corticosteroid therapy

Background: T cells are considered the main cells responsible for production of suppressive cytokines, and play a key role in balancing the immune responses to maintain the peripheral tolerance against allergens. Objective: The present study investigates T regulatory (Treg) forkheadwinged helix protein 3 FOXP3 expression in childhood asthma and its relation to corticosteroid therapy. Methods: In this case control study, Treg FOXP3 was measured in blood of 60 children using real time polymerase chain reaction (RT-PCR) technique. Two asthmatic groups were included, one on corticosteroid therapy (20 patients) and the other not on corticosteroid treatment (20 patients). They were compared to 20 healthy children as controls. Results: FOXP3 concentration was significantly elevated in asthmatic patients (90 ± 77.4) compared to healthy children (12.844 ± 10.6) (p= 0.000). FOXP3 was significantly more elevated in asthmatics on corticosteroids (161.158 ± 63.9) than steroid naive asthmatics (36.038 ± 23.4) (p=0.000). Levels of Treg FOXP3 in asthmatics with inhaled corticosteroids (mean 151.16 ± 53.79) were almost similar to FOXP3 in asthmatics with systemic corticosteroids (161.49±72.5) (p&gt;0.05). FOXP3 levels did not differ with smoking, asthma severity or disease control and did not correlate with age, FEV1, blood lymphocytes percentage or eosinophils percentage. Conclusion: Asthmatics have increased expression of FOXP3, and corticosteroid therapy –whether oral or inhaled - enhances FOXP3 expression.Keywords: FOXP3, Treg, Corticosteroids, Bronchial asthma, Transcription factors, CytokinesEgypt J Pediatr Allergy Immunol 2012;10(1):39-43

Chronic endometritis in cases with recurrent embryo implantation failure

Background: Chronic endometritis (CE) is a cause of recurrent implantation failure (RIF) in patients undergoing intracytoplasmic sperm injection (ICSI). CE is diagnosed based on the presence of plasma cell infiltration of the endometrial stroma in endometrial biopsies. Hysteroscopy may be suggestive of CE while the immunohistochemistry with specific cell markers for CD138 cells has been suggested as a more accurate test for the diagnosis of CE.Methods: This study included 110 patients with recurrent ICSI failure (two or more), despite using good-quality embryos. Hysteroscopy and endometrial biopsy were performed as an outpatient procedure. Immunostaining was then performed using a mouse monoclonal CD138 antibody. The prevalence rate of CE was calculated, and the correlation between hysteroscopic findings and immunohistochemical results was assessed. Results: In the included patients in this study there was 32 cases (29%) were diagnosed as CE by hysteroscopy, while 27 cases (24.5%) were positive by CD138 immunohistochemistry (IHC), and 18 cases (16.36%) were positive for CD138 IHC with hysteroscopic features of CE. The presence of more than one abnormal hysteroscopic features was considered positive for CE rather than single abnormal feature, the sensitivity, specificity, positive and negative predictive values of hysteroscopy would be 22.2%, 98.8%, 85.7%, and 79.6%, respectively.Conclusions: The negative diagnostic value of hysteroscopy is high, the combination of the two diagnostic modalities (hysteroscopy and CD138 IHC) will aid in the detection of most cases of CE

Evaluation of serum levels of Interleukin-4 in Egyptian patients with refractory gastroesophageal reflux disease

Introduction: Gastroesophageal reflux disease is defined as bothersome symptoms and/or complications caused by the reflux of stomach contents. About 40–50% of patients develop refractory gastroesophageal reflux disease (R-GERD), with poor improvement of symptoms with treatment. Many pathogenic mechanisms share in development of R-GERD, among which is the important role of T-helper 1 and T-helper 2 response mediated by cytokines. The interleukin-4 is a cytokine known of its anti-inflammatory effect. In this study, we aimed to evaluate the level of interleukin-4 in Egyptian patients with R-GERD versus those with GERD. PATIENTS AND Methods: Our study included 25 patients with reflux symptoms who received PPIs for less than 8 weeks with improvement of symptoms, versus 25 patients with refractory reflux symptoms who received PPIs for more than 8 weeks without improvement of symptoms. Interleukin-4 levels were assessed in both groups by ELISA. Results: There was a statistically significant difference between the two groups as regard interleukin-4 levels (p &lt; 0.012) which was higher in the patients with (R-GERD), the mean level of IL-4 was 37.31 ± 56.07 in GERD group while in R-GERD group, it was 102.78 ± 112.29. The diagnostic accuracy of interleukin-4 revealed a sensitivity of 56% and specificity of 76% at cutoff value &gt;58.25 pg/ml, with an acceptable accuracy of 0.6. Conclusions: The present study concluded that IL-4 is significantly higher in patients with R GERD with cut off value &gt; 58.25 pg/ml. Therapeutic strategies that modulate the production of IL-4 may provide a good solution for treatment of R GERD

Physician-Controlled Wire-Guided Cannulation of the Minor Papilla

Background. Minor papilla (MiP) cannulation is frequently performed using specialized small-caliber accessories. Outcomes data for MiP cannulation with standard-sized accessories are lacking. Methods. This is a case series describing MiP cannulation outcomes in consecutive patients treated by two endoscopists between July 2005 and November 2008 at two tertiary referral centers. MiP cannulation was attempted using a 4.4 Fr tip sphincterotome loaded with a 0.035″, 260 cm hydrophilic-tip guidewire, using a wire-guided technique under physician control. Results. 25 patients were identified (14 women, mean age 45). Procedure indications included recurrent acute pancreatitis in 16 patients (64%) and chronic pancreatitis in 2 (8%), among other indications. MiP cannulation was successful in 24 patients (96%). Sphincterotomy followed by pancreatic stent placement was performed in 21 patients (84%). Mild post-ERCP pancreatitis occurred in 3 patients (12%). Conclusion. Physician-controlled wire-guided MiP cannulation using a 4.4 Fr sphincterotome and 0.035″ guidewire is an effective and safe technique