Long-Lived Double-Barred Galaxies: Critical Mass and Length Scales

A substantial fraction of disk galaxies is double-barred. We analyze the dynamical stability of such nested bar systems by means of Liapunov exponents,by fixing a generic model and varying the inner (secondary) bar mass. We show that there exists a critical mass below which the secondary bar cannot sustain its own orbital structure, and above which it progressively destroys the outer (primary) bar-supporting orbits. In this critical state, a large fraction of the trajectories (regular and chaotic) are aligned with either bar, suggesting the plausibility of long-lived dynamical states when secondary-to-primary bar mass ratio is of the order of a few percent. Qualitatively similar results are obtained by varying the size of the secondary bar, within certain limits, while keeping its mass constant. In both cases, an important role appears to be played by chaotic trajectories which are trapped around (especially) the primary bar for long periods of time.Comment: 7 pages, 1 figure, to be published in Astrophysical Journal Letters (Vol. 595, 9/20/03 issue). Replaced by revised figure and corrected typo

Blood Transfusion in Patients with Sickle Cell Disease Requiring Laparoscopic Cholecystectomy

Laparoscopic cholecystectomy in patients with sickle cell disease was found to be safe without preoperative blood transfusion

The phenomenology of premenstrual syndrome in female medical students: a cross sectional study

Background: The premenstrual syndrome (PMS) is particularly common in the younger age groups and, therefore represents a significant public health problem in young girls. This study aims to estimate the prevalence, severity, determinants of premenstrual syndrome (PMS) and its impact among the female medical students in Al-Ahsa, Saudi Arabia. Method: This study was performed at the College of Medicine, King Faisal University, Saudi Arabia, from June through December 2009. It included 250 medical students. They filled different questionnaires covering American College of Obstetrics and Gynecology (ACOG) criteria to diagnose PMS, demographic & reproductive factors, physical activity and mental condition. Regression analysis was conducted for all the predictors. Results: PMS was diagnosed in 35.6% of cases, distributed as 45% mild, 32.6% moderate and 22.4% severe. There were significant trends for older age, rural residence, family income and family history of PMS. The dominant limited activity was concentration in class (48.3%). Limitations of activities were significantly more frequent among severe cases. The prevalence of anxiety and depression was statistically more evident in the PMS group. Regression analysis revealed that, PMS was significantly associated with older age groups, rural residence, lower age at menarche, regularity of menses and family history. Conclusion: PMS is a common problem in young Saudi students in Al Ahsa. Severe PMS was associated with more impairment of daily activities and psychological distress symptoms. Older student age, rural residence, earlier age of menarche, regular cycles and positive family history are possible risk factors for PMS

Case Report: Bilateral absence of fifth ray in feet, cleft palate, malformed ears, and corneal opacity in a patient with Miller syndrome

Background: Miller syndrome is one of the acrofacial dysostosis syndromes, which are characterized by malformations of the craniofacial region and limbs.Case report: A 26 month old male child, the product of healthy nonconsanguineous parents has many typical features of Miller syndrome. He has cleft lip and palate, malar hypoplasia, left crumpled cup shaped ear, and prominent nose together with the absence of the fifth ray in feet (postaxial) and fixation of interphalangeal joints of both thumbs (preaxial). However the limb affection is bilateral and symmetrical against what is usually reported (bilateral with more affection of one side) and the micrognathia is very mild. Our patient has also bilateral corneal opacities as well as underdeveloped external genitals.Conclusion: There is phenotypic variability in Miller syndrome, and our patient may represent a new distinct subgroup in postaxial acrofacial dysostosis.Keywords: Miller syndrome; Gene´e–Weidemann syndrome; Postaxial acrofacial dysostosis syndrome; Corneal opacit

Craniofacial proportions and anthropometric measurements among growth hormone deficient Egyptian children

Introduction: Untreated children with growth hormone deficiency (GHD) have typical somatic features, including short stature, acromicria and distinctive craniofacial features including small head circumference. Patients and Methods: By using a cross sectional study design, we investigated the effect of GHD on craniofacial growth with photographic facial morphometrics & various anthropometric measurements, in 20 children with GHD compared with 20 healthy children and normal first degree relatives of the same age and sex group. Results: Untreated children with GHD had retarded facial height & width (

Superior Mesenteric Artery Syndrome Following Augmentation Cystoplasty

Superior mesenteric artery syndrome (SMAS) is a rare condition of external duodenal compression in the angle between the superior mesenteric artery and aorta. We report a case of SMAS following augmentation cystoplasty in a young patient. Superior mesenteric artery syndrome (SMAS) is a rare condition that usually presents with symptoms of upper gastrointestinal (GI) obstruction due to extrinsic compression of the third part of duodenum between the abdominal aorta posteriorly and superior mesenteric artery (SMA) anteriorly. Several predisposing factors have been described, however; severe weight loss is considered the most significant. Reduction in the angle and distance between the aorta and the SMA causes compression of the duodenum. Conservative treatment plays a major role in such cases; however, failure of such measures may warrant surgical intervention

Direct cord implantation in brachial plexus avulsions: revised technique using a single stage combined anterior (first) posterior (second) approach and end-to-side side-to-side grafting neurorrhaphy

<p>Abstract</p> <p>Background</p> <p>The superiority of a single stage combined anterior (first) posterior (second) approach and end-to-side side-to-side grafting neurorrhaphy in direct cord implantation was investigated as to providing adequate exposure to both the cervical cord and the brachial plexus, as to causing less tissue damage and as to being more extensible than current surgical approaches.</p> <p>Methods</p> <p>The front and back of the neck, the front and back of the chest up to the midline and the whole affected upper limb were sterilized while the patient was in the lateral position; the patient was next turned into the supine position, the plexus explored anteriorly and the grafts were placed; the patient was then turned again into the lateral position, and a posterior cervical laminectomy was done. The grafts were retrieved posteriorly and side grafted to the anterior cord. Using this approach, 5 patients suffering from complete traumatic brachial plexus palsy, 4 adults and 1 obstetric case were operated upon and followed up for 2 years. 2 were C5,6 ruptures and C7,8T1 avulsions. 3 were C5,6,7,8T1 avulsions. C5,6 ruptures were grafted and all avulsions were cord implanted.</p> <p>Results</p> <p>Surgery in complete avulsions led to Grade 4 improvement in shoulder abduction/flexion and elbow flexion. Cocontractions occurred between the lateral deltoid and biceps on active shoulder abduction. No cocontractions occurred after surgery in C5,6 ruptures and C7,8T1 avulsions, muscle power improvement extended into the forearm and hand; pain disappeared.</p> <p>Limitations include</p> <p>spontaneous recovery despite MRI appearance of avulsions, fallacies in determining intraoperative avulsions (wrong diagnosis, wrong level); small sample size; no controls rule out superiority of this technique versus other direct cord reimplantation techniques or other neurotization procedures; intra- and interobserver variability in testing muscle power and cocontractions.</p> <p>Conclusion</p> <p>Through providing proper exposure to the brachial plexus and to the cervical cord, the single stage combined anterior (first) and posterior (second) approach might stimulate brachial plexus surgeons to go more for direct cord implantation. In this study, it allowed for placing side grafts along an extensive donor recipient area by end-to-side, side-to-side grafting neurorrhaphy and thus improved results.</p> <p>Level of evidence</p> <p>Level IV, prospective case series.</p

Effect of Blast Loading on Seismically Detailed RC Columns and Buildings

Explosions caused by standoff charges near buildings have drastic effects on the internal and external structural elements which can cause loss of life and fatal injuries in case of failure or collapse of the structural element. Providing structural elements with blast resistance is therefore gaining increasing importance. This paper presents numerical investigation of RC columns with different reinforcement detailing subjected to near-field explosions. Detailed finite element models are made using LS-DYNA software package for several columns having seismic and conventional reinforcement detailing which were previously tested under blast loads. The numerical results show agreement with the published experimental results regarding displacements and damage pattern. Seismic detailing of columns enhances the failure shape of the column and decrease the displacement values compared to columns with conventional reinforcement detailing. Further, the effect of several modeling parameters are studied such as mesh sensitivity analysis, inclusion of air medium and erosion values on the displacements and damage pattern. The results show that decreasing the mesh size, increasing erosion value and inclusion of air region provide results that are very close to experimental results. Additionally, application is made on a slab-column multistory building provided with protective walls having different connection details subjected to blast loads. The results of this study are presented and discussed. Use of a top and bottom floor slab connection of protective RC walls are better than using the full connection at the four sides to the adjacent columns and slabs. This leads to minimizing the distortion and failure of column, and therefore it increases the chance of saving the building from collapse and saving human lives. Doi: 10.28991/cej-2021-03091733 Full Text: PD