Experimental and numerical analyses of laminar boundary-layer flow stability over an aircraft fuselage forebody

Fuelled by a need to reduce viscous drag of airframes, significant advances have been made in the last decade to design lifting surface geometries with considerable amounts of laminar flow. In contrast to the present understanding of practical limits for natural laminar flow over lifting surfaces, limited experimental results are available examining applicability of natural laminar flow over axisymmetric and nonaxisymmetric fuselage shapes at relevantly high length Reynolds numbers. The drag benefits attainable by realizing laminar flow over nonlifting aircraft components such as fuselages and nacelles are shown. A flight experiment to investigate transition location and transition mode over the forward fuselage of a light twin engine propeller driven airplane is examined

Serrated trailing edges for improving lift and drag characteristics of lifting surfaces

An improvement in the lift and drag characteristics of a lifting surface is achieved by attaching a serrated panel to the trailing edge of the lifting surface. The serrations may have a saw-tooth configuration, with a 60 degree included angle between adjacent serrations. The serrations may vary in shape and size over the span-wise length of the lifting surface, and may be positioned at fixed or adjustable deflections relative to the chord of the lifting surface

Soul or Brain: A False Dilemma? The Thomist Perspective

In this article I will claim that from a Thomist perspective the question “Soul or Brain: What makes us human?” presents us with a false dilemma and hence must as such remain an unanswerable question. In order to corroborate this claim I will do two things. First, I present the framework of a Thomistic anthropology in so far as it relates to the unity of soul and body in the human person. Next, I deal with the question that immediately results from this unity, i.e. the subsistence of the soul. From a Thomist perspective this question can be answered apart from any findings from neuroscience

Revision of Laparoscopic Adjustable Gastric Banding: Success or Failure?

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) is a safe and frequently performed bariatric procedure. Unfortunately, re-operations are often necessary. Reports on the success of revisional procedures are scarce and show variable results, either supporting or declining the idea of revising LAGB. This study describes a large cohort of re-operations after failed LAGB to determine the success of revision. METHODS: By use of a prospective cohort, all LAGB revisions performed between 1996 and 2008 were identified. From 301 primary LAGB procedures in our centre, 43 patients (14.3%) required a band revision. In addition, 51 patients were referred from other centres. Our analysis included in total 94 patients with a mean follow-up period of 38 months after revision. RESULTS: Revision was mainly necessary due to anterior slippage (46%) and symmetrical pouch dilatation (36%), which could be resolved by replacing (70%) or refixating the band (27%). Weight loss significantly increased after revision (excess BMI loss (EBMIL), 37.2 +/- 36.3% versus 47.5 +/- 30.4%, P < 0.05). After revision, 23 patients (24%) needed a second re-operation. Patients converted to other procedures (16%) during the second re-operation showed larger weight loss than the revised group (EBMIL, 64.3 +/- 28.1% versus 44.3 +/- 28.7%, P < 0.05). CONCLUSIONS: We report on a large cohort of LAGB revisions with 38 months of follow-up. Revision of failed LAGB by either refixation or replacement of the band is successful and further increases weight loss

Brown Adipose Tissue in Morbidly Obese Subjects

BACKGROUND: Cold-stimulated adaptive thermogenesis in brown adipose tissue (BAT) to increase energy expenditure is suggested as a possible therapeutic target for the treatment of obesity. We have recently shown high prevalence of BAT in adult humans, which was inversely related to body mass index (BMI) and body fat percentage (BF%), suggesting that obesity is associated with lower BAT activity. Here, we examined BAT activity in morbidly obese subjects and its role in cold-induced thermogenesis (CIT) after applying a personalized cooling protocol. We hypothesize that morbidly obese subjects show reduced BAT activity upon cold exposure. METHODS AND FINDINGS: After applying a personalized cooling protocol for maximal non-shivering conditions, BAT activity was determined using positron-emission tomography and computed tomography (PET-CT). Cold-induced BAT activity was detected in three out of 15 morbidly obese subjects. Combined with results from lean to morbidly obese subjects (n = 39) from previous study, the collective data show a highly significant correlation between BAT activity and body composition (P<0.001), respectively explaining 64% and 60% of the variance in BMI (r = 0.8; P<0.001) and BF% (r = 0.75; P<0.001). Obese individuals demonstrate a blunted CIT combined with low BAT activity. Only in BAT-positive subjects (n = 26) mean energy expenditure was increased significantly upon cold exposure (51.5±6.7 J/s versus 44.0±5.1 J/s, P = 0.001), and the increase was significantly higher compared to BAT-negative subjects (+15.5±8.9% versus +3.6±8.9%, P = 0.001), indicating a role for BAT in CIT in humans. CONCLUSIONS: This study shows that in an extremely large range of body compositions, BAT activity is highly correlated with BMI and BF%. BAT-positive subjects showed higher CIT, indicating that BAT is also in humans involved in adaptive thermogenesis. Increasing BAT activity could be a therapeutic target in (morbid) obesity

The Influence of Surgical Experience on Postoperative Recovery in Fast-Track Bariatric Surgery

Introduction: Short duration of surgery is an important aspect in fast-track protocols. Peroperative training of surgical residents could influence the duration of surgery, possibly affecting patient outcome. This study evaluates the influence of the operator’s level of experience on patient outcome in fast-track bariatric surgery. Methods: Data was analyzed of all patients who underwent a primary laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) between January 2004 and July 2018. Residents were trained according to a stepwise training program. For each operator, learning curves of both procedures were created by dividing the procedures in time-subsequent groups (TSGs). Data was also analyzed by comparing “beginners” with “experienced operators,” with a cut-off point at 100 procedures. Primary outcome measure was duration of surgery. Secondary outcome measures were length of hospital stay (LOS), complications, and readmission rate within 30 days postoperatively. Results: There were 4901 primary procedures (53.1% LSG) performed by seven surgeons or surgical residents. We found no difference between beginning and experienced operators in complications or readmissions rates. The experience of the operator did not influence LOS (p = 0.201). Comparing each new operator with previous operator(s), the starting point in terms of duration of surgery was shorter, and thcorresponding author at Franciscus Gasthuis & Vlietland Rotterda

Quality of Life 1 Year After Laparoscopic Sleeve Gastrectomy Versus Laparoscopic Roux-en-Y Gastric Bypass: a Randomized Controlled Trial Focusing on Gastroesophageal Reflux Disease

Introduction: Bariatric surgery is the only treatment option that achieves sustained weight loss in obese patients and that also has positive effects on obesity-related comorbidities. Laparoscopic sleeve gastrectomy (LSG) seems to achieve equal weight loss as laparoscopic Roux-en-Y gastric bypass (LRYGB), but there is still much debate about the quality of life (QOL) after LSG, mainly concerning the association with gastroesophageal reflux. Our hypothesis is that QOL after LSG is comparable with QOL after LRYGB. Materials and Methods: Between February 2013 and February 2014, 150 patients were randomized to undergo either LSG or LRYGB in our clinic. Differences in QOL were compared between groups by using multiple QOL questionnaires at follow-up moments preoperatively and 2 and 12 months after surgery. Results: After 12 months of follow-up, 128 patients had returned the questionnaires. Most QOL questionnaires showed significant improvement in scores between the preoperative moment and after 12 months of follow-up. The Gastroesophageal Reflux Disease Questionnaire (GerdQ) score deteriorated in the LSG group after 2 months, but recovered again after 12 months. After 2 months of follow-up, the mean GerdQ score was 6.95 ± 2.14 in the LSG group versus 5.50 ± 1.49 in the LRYGB group (p < 0.001). After 1 year, the mean GerdQ score was 6.63 ± 2.26 in the LSG group and 5.60 ± 1.07 in the LRYGB group (p = 0.001). Conclusion: This randomized controlled trial shows that patients who underwent LSG have significantly higher GerdQ scores at both 2 and 12 months postoperatively than patients who underwent LRYGB, whereas overall QOL did not differ significantly

Dordt College 2003-2004 Catalog

Academic Catalog for 2003-04https://digitalcollections.dordt.edu/academic_catalogs/1012/thumbnail.jp

Full-genome deep sequencing and phylogenetic analysis of novel human betacoronavirus

A novel betacoronavirus associated with lethal respiratory and renal complications was recently identified in patients from several countries in the Middle East. We report the deep genome sequencing of the virus directly from a patient's sputum sample. Our high-throughput sequencing yielded a substantial depth of genome sequence assembly and showed the minority viral variants in the specimen. Detailed phylogenetic analysis of the virus genome (England/Qatar/2012) revealed its close relationship to European bat coronaviruses circulating among the bat species of the Vespertilionidae family. Molecular clock analysis showed that the 2 human infections of this betacoronavirus in June 2012 (EMC/2012) and September 2012 (England/Qatar/2012) share a common virus ancestor most likely considerably before early 2012, suggesting the human diversity is the result of multiple zoonotic events