Comparison of residual shear strength determined by different methods

The shear stress of stiff or dense soils increases with the displacement and reaches itsmaximum value, and then shear stress decreases and remains a constant value. The minimumand constant shear stress of soils reached at large shear displacements is called as residualshear strength. Residual shear strength generally has a great importance in design ofengineering structures constructed on fissured overconsolidated clays and long-term slopestability analysis in geotechnical engineering. In laboratory testing, modeling the residualconditions of a soil requires large shear displacements attained in drained conditions.Reversal direct shear test (RDS), consolidated-drained triaxial test (CD) and torsional ringshear test (RS) are the widely used testing methods to determine residual shear strengthparameters. These methods have some advantages or limitations when compared with eachother. In this study, residual shear strength parameters of soil samples having different clayfractions were determined by the three different drained tests, the results were compared, andeffect of the testing methods on residual shear strength was investigated. The variation ofresidual shear strength angle versus liquid limit and plasticity index were studied. The resultswere compared with previous studies. As a result, it is found that the residual shear strengthangle determined by the ring shear test is lower than the others, and the residual shear strengthangle decreases with the increasing liquid limit and plasticity index

A Reinforcement Learning Based Controller to Minimize Forces on the Crutches of a Lower-Limb Exoskeleton

Metabolic energy consumption of a powered lower-limb exoskeleton user mainly comes from the upper body effort since the lower body is considered to be passive. However, the upper body effort of the users is largely ignored in the literature when designing motion controllers. In this work, we use deep reinforcement learning to develop a locomotion controller that minimizes ground reaction forces (GRF) on crutches. The rationale for minimizing GRF is to reduce the upper body effort of the user. Accordingly, we design a model and a learning framework for a human-exoskeleton system with crutches. We formulate a reward function to encourage the forward displacement of a human-exoskeleton system while satisfying the predetermined constraints of a physical robot. We evaluate our new framework using Proximal Policy Optimization, a state-of-the-art deep reinforcement learning (RL) method, on the MuJoCo physics simulator with different hyperparameters and network architectures over multiple trials. We empirically show that our learning model can generate joint torques based on the joint angle, velocities, and the GRF on the feet and crutch tips. The resulting exoskeleton model can directly generate joint torques from states in line with the RL framework. Finally, we empirically show that policy trained using our method can generate a gait with a 35% reduction in GRF with respect to the baseline.Comment: 6 pages, 5 Figure

Deneysel periodontitis oluşturulmuş diyabetik sıçanlarda α-tokoferol’ün alveoler kemik kaybı üzerine etkileri

ÖZETAmaç: Birçok deneysel ve klinik çalışmada diyabetin periodonsiyum üzerinde yaptığı değişiklikler değerlendirilirken bunun yanında periodontitisin diyabet durumuna etkiside araştırılmıştır. Bu araştırmanın amacı, deneysel periodontitis ve streptozotosin (STZ) ile diyabet oluşturulan/oluşturulmayan sıçanlarda a-tokoferol uygulamasının alveoler kemik kaybı üzerindeki etkilerini araştırmaktır.Gereç ve Yöntemler:Çalışmaya kırk adet erkek Sprague Dawley sıçana dahil edildi ve anestezi uygulandıktan sonra mandibular sağ birinci molar dişlere subgingival olarak 3/0 ipek sütur bağlandı. Bu hayvanlar, sağlıklı grup (Grup I) ve tek seferde 50 mg/kg STZ enjekte edilen diyabetik grup (Grup II) olmak üzere iki gruba ayrıldı. Bu gruplarda serum fizyolojik (Grup IA, Grup IIA) ve a-tokoferol (40mg/kg/gün) enjekte edilen alt gruplara (Grup IB, Grup IIB) ayrıldı. Ligatür bağlandıktan 3 hafta sonra sıçanlar kurban edildi ve dokular histometrik ölçümler için nötral tamponlanmış %10’luk formaldehit solüsyonunda sabitlendi. Alveoler kemik kaybı (AKK), görüntü analiz programı kullanılarak analiz edildi. İstatistiksel kıyaslamalar için iki-yönlü varyans analizi, kullanıldı p<0.05 anlamlılık düzeyi kabul edildi.Bulgular: Histometrik incelemeden sonra veriler değerlendirildi ve istatistiksel olarak gruplar arasında AKK düzeyleri farklı bulunmadı (p>0.05).Sonuçlar: Verilerin değerlendirilmesi sonucunda a-tokoferol uygulamasının deneysel periodontitisli STZ ile diyabet oluşturulmuş/oluşturulmamış sıçanlarda AKK üzerinde bir etki oluşturmadığı gösterildi.Anahtar kelimeler: Diyabet, a-tokoferol, AKK, deneysel periodontitis.SUMMARYBackground: A variety of clinical and experimental studies investigated the influence of diabetes on the periodontium, as well as the impact of periodontitis on diabetes status. The aim of this study was to investigate the effects of a-tocopherol on alveolar bone loss in rats with experimental periodontitis with/without streptozotocin (STZ)-induced diabetes.Methods: Forty male Sprague Dawley rats were included in the study and after anesthesia 3/0 silk sutures were placed at the subgingival level of the mandibular right first molars. These animals were divided into two groups: Healty group (Group I) and diabetic group by single injection of 50 mg/kg STZ(Group II). These groups divided into two subgroups; twenty rats were saline group (Group IA, Group IIA) and other twenty rats (Group IB, Group IIB) were a-tocopherol(40mg/kg/day) group. After 3 weeks, all rats were sacrified and the tissues were fixed using neutral buffered 10% formaldehyde solution for histometrical investigation. Alveolar bone loss (ABL), were analyzed by using image analysis program. Statistical comparisons were performed by using two-way analysis of variance with significance set at p<0.05.Results: Data were evaluated after the histometrical examination and there were no statistically significant differences in ABL between the study groups (p>0.05). Conclusion: Analysis of these data demonstrated that a-tocopherol treatment was not affected the ABL of rats with experimental periodontitis with/without STZ-induced diabetes.Key Words: Diabetes, a-tocopherol, ABL, experimental periodontitis

Rectus sheath hematoma: three case reports

<p>Abstract</p> <p>Introduction</p> <p>Rectus sheath hematoma is an uncommon cause of acute abdominal pain. It is an accumulation of blood in the sheath of the rectus abdominis, secondary to rupture of an epigastric vessel or muscle tear. It could occur spontaneously or after trauma. They are usually located infraumblically and often misdiagnosed as acute abdomen, inflammatory diseases or tumours of the abdomen.</p> <p>Case presentation</p> <p>We reported three cases of rectus sheath hematoma presenting with a mass in the abdomen and diagnosed by computerized tomography. The patients recovered uneventfully after bed rest, intravenous fluid replacement, blood transfusion and analgesic treatment.</p> <p>Conclusion</p> <p>Rectus sheath hematoma is a rarely seen pathology often misdiagnosed as acute abdomen that may lead to unnecessary laparotomies. Computerized tomography must be chosen for definitive diagnosis since ultrasonography is subject to error due to misinterpretation of the images. Main therapy is conservative management.</p

A Prospective Study of Etiology of Childhood Acute Bacterial Meningitis, Turkey

Vaccines to prevent bacterial meningitis in this region must provide reliable protection against serogroup W-135

Characterization of greater middle eastern genetic variation for enhanced disease gene discovery

The Greater Middle East (GME) has been a central hub of human migration and population admixture. The tradition of consanguinity, variably practiced in the Persian Gulf region, North Africa, and Central Asia1-3, has resulted in an elevated burden of recessive disease4. Here we generated a whole-exome GME variome from 1,111 unrelated subjects. We detected substantial diversity and admixture in continental and subregional populations, corresponding to several ancient founder populations with little evidence of bottlenecks. Measured consanguinity rates were an order of magnitude above those in other sampled populations, and the GME population exhibited an increased burden of runs of homozygosity (ROHs) but showed no evidence for reduced burden of deleterious variation due to classically theorized ‘genetic purging’. Applying this database to unsolved recessive conditions in the GME population reduced the number of potential disease-causing variants by four- to sevenfold. These results show variegated genetic architecture in GME populations and support future human genetic discoveries in Mendelian and population genetics