Flow Velocity Effect on Clear Water Bridge Pier Scour

For a long while, scour mechanism has been a major problem to be solved by many researchers. Local scour phenomenon at bridge piers has many parameters such as flow characteristics, sediment type, bridge pier shape and alignment. To find a general scour equation under the same conditions, the effect rate of any parameter has to be determined. After the determination phase, the rectifier coefficients for a valid equation can be easily calculated for scour estimation. In order to specify whether the scour condition is clear-water or live-bed, the velocity parameter has to be substituted into scour equations because the determinative factor between these two conditions is the flow velocity. Accordingly in this study, the effect of the ratio of mean approach flow velocity to the critical mean approach flow velocity for entrainment of bed sediment (V/Vc) has been investigated. Three of the mostly used empirical scour formulations, did not take into account the flow velocity, but they are rectified to verify this effect. The data set belongs to four previous studies. Since the parameter, V/Vc, is a dimensionless factor the physical characters of these equations are not altered significantly. However, importation of this parameter into the currently available formulations improves the calculation results in significant manner

Cyclostationarity based blind block timing estimation for alamouti coded mimo signals

Blind parameter estimation algorithms provide a powerful tool for application scenarios where the use of training or pilot sequences is not desirable, e.g., in order to improve the bandwidth efficiency of the transmission, or in non-cooperative scenarios where such sequences are not available to the receiver. This letter proposes a blind block timing estimation algorithm for Alamouti space-time block coded signals exploiting the second order joint cyclostationary characteristics of the received signal vector, which is induced by the space time block coding operation performed by the transmitter. The proposed algorithm outperforms the existing algorithms by a wide margin

Effect of Pterygium Surgery on Tear Osmolarity

Purpose. To investigate changes of dry eye test results in patients who underwent pterygium surgery. Methods. Seventy-four patients who underwent primary pterygium surgery were enrolled in this study. At the baseline, 3-, 12-, and 18-month visits, measurements of tear osmolarity, BUT, and Schirmer test were performed. The patients were divided into 2 groups: Group 1, which consisted of patients in whom pterygium did not recur, and Group 2, which consisted of patients in whom pterygium recurred after surgery. Results. The patients in Group 1 had lower tear osmolarity levels after surgery than those at baseline (all P0.05). Conclusions. Anormal tear film function associated with pterygium. Pterygium excision improved tear osmolarity and tear film function. However, tear osmolarity deteriorated again with the recurrence of pterygium

A conceptual view of exergy destruction in mergers and acquisitions

Company mergers are complex where several firm-specific and contextual factors interact with each other impacting the outcome of the process. Although many firms merge with or acquire others to increase the value of their firms, have more market power and gain more ability to negotiate with suppliers or customers, most of mergers and acquisitions result in failures. Despite the poor performances, firms continue to merge and acquire. The existing literature on the other hand lacks in providing a robust theory to the issue of poor post-merger performance. This study thus responds to exploring the issue of high failure rates in mergers and acquisitions in an entirely different way. As the first output of a research programme on the conceptual, theoretical and empirical issues in merger and acquisitions research, we conceptualize the loss of performance or exergy in mergers and acquisitions using thermodynamic analysis of the mixing process in physical systems. Three propositions are developed that conceptualize the ideal conditions for mergers in terms of firm size, relatedness between the merging firms and the ambient states. The exergy loss due to merging increases with the increasing levels of strategic or cultural incompatibility between the two firms. When the sizes of two firms differ, it is preferable for the larger firm to have higher knowledge base than the smaller firm. Lastly, the knowledge intensity of the country that the merging takes place as well as the relative knowledge base of the merging firms do interact and change the post-merger performance significantly

Clopidogrel responsiveness in chronic kidney disease patients with acute coronary syndrome

Objective: Cardiovascular diseases are the leading cause of death in patients with chronic kidney disease (CKD). There is conflicting evidence about effect of CKD on clopidogrel responsiveness. We aimed to evaluate the clopidogrel responsiveness in CKD patients with acute coronary syndrome (ACS). Methods: A total of 101 patients; 55 with moderate to severe CKD and 46 with normal renal function or mild CKD, hospitalized with ACS were included in our study. Multiplate test was used to determine clopidogrel responsiveness. Platelet aggregation results were presented as aggregation unit (AU)*min and values over 470 AU*min were accepted as clopidogrel low responders. Results: The 101 patients (mean age 64.76±8.67 years; 61 [60.4%] male) were grouped into the two study groups as follows: group 1; 55 patients with eGFR<60 ml/min/1.73 m2 and group 2; 46 patients with eGFR>60 ml/min/1.73 m2. 35 patients (34.7%) of the study population were found to have low response to clopidogrel (16 [34.8%] patients in group 1 and 18 [33.3%] patients in group 2, p=0.879) . There was no significant difference between group 1 and 2 for Multiplate test results (414.67±281.21 vs 421.56±316.19 AU*min, p=0.909). Clopidogrel low responsiveness were independently related to Multiplate test results of aspirin responsiveness (OR=1.004, CI 1.002–1.007, p=0.001) and hemoglobin (OR=0.727, CI 0.571–0.925, p=0.010). Multiplate results were also independently related to Multiplate test results of aspirin responsiveness (β=0.402, p<0.0001) and hemoglobin (β=-0.251, p=0.007). Conclusion: Platelet response to clopidogrel does not differ between patients with eGFR < 60 ml/min/1.73 m2 and eGFR>60 ml/min/1.73 m2

LONG-TERM OUTCOMES OF HEMICENTRAL RETINAL VEIN OCCLUSION

Amaç: Hemi-Santral Retinal Ven Tıkanıklığı (HSRVT) tanısıyla izlenen olguların uzun dönem takiplerinde görme sonuçlarını ve komplikasyonları değerlendirmek. Yöntemler: Ocak 1992-Ocak 2001 tarihleri arasında optik koherens tomografi öncesi döneme ait HSRVT tanısı konulan, 2 yıl ve üzeri düzenli takibi olan 25 hastanın 25 gözü retrospektif dosyaları taranarak incelendi. Dosya incelemelerinde hastaların yaşı, cinsiyeti, sistemik risk faktörleri, hangi gözün etkilendiği, tam oftalmolojik muayeneleri ve gelişen komplikasyonlar kaydedildi. İlk başvuda çekilen Fundus Fluoresein Anjiografi (FA) sonuçları incelendi. Hastalar FA bulgularına (noniskemik veya iskemik form) ve üst ya da alt retinal yarı etkilenmesine göre sınıflandırıldı. Bulgular: Hastaların ortalama yaşı 67,0 ± 11,0 yıl (41-90 yıl) ve ortalama takip süresi 6,4 ± 5,5 yıl (2-19 yıl) idi. Olguların 17'sinde (%68) sistemik bir hastalık mevcut olup, en büyük çoğunluğu hipertansiyon hastaları (%48) oluşturmaktaydı. Gözlerin 13'ünde (%52) alt hemisferik kadran ve 12'sinde (%48) üst hemisferik kadranda etkilenme olduğu saptandı. Hastalarımızın tanı esnasında görme keskinliği tüm gözlerde ortalama 1,08 ± 0,4 logMAR iken, son muayenede ortalama 0,89 ± 0,5 logMAR olarak saptandı (p&gt;0,05). FA bulgularına göre tanı esnasında 10 gözde iskemi ve takiplerde noniskemik olguların 3'ünde iskemik forma dönüşüm tespit edildi. On disk alanından daha geniş iskemik alanlara retinal laser fotokoagülasyon uygulandı. HSRVT'ye bağlı 12 gözde makula ödemi, 3 gözde intravitreal hemoraji, 3 gözde epiretinal membran formasyonu, 3 gözde neovasküler glokom, 2 gözde optik atrofi ve 1 gözde yırtıklı retina dekolmanı geliştiği gözlendi. Perfüze makula ödemi tedavisinde grid laser fotokoagülasyon uygulandı. Sonuç: Hastaların uzun dönem takipte görme prognozu, başlangıç görme keskinliği ve komplikasyon gelişimi ile ilişkili bulundu. Hastaların uzun dönem takiplerinde rölatif görme artışı sağlansa bile, bu artış istatistiksel olarak anlamlı bulunmadı Objective: To assess the visual outcomes and the complications in patients with Hemicentral Retinal Vein Occlusion (HCRVO) in the long-term. Methods: The medical records of 25 eyes of 25 patients, having regular follow-up for ≥2 years, diagnosed as HCRVO before Optical Cohorence Tomography (OCT) era between January 1992 and January 2001 were reviewed. During the survey, gender,age, affected side, complete ophthalmologic evaluations, systemic risk factors and complications were recorded. The images of Fundus Fluorescein Angiography (FA) at baseline were evaluated. The patients were classified according to the findings of the FA (non-ischemic or ischemic form) and the involvement of superior or inferior halves of the retina. Results: The mean age of the patients was 67.0 ± 11.0 years (range, 41-90 years) and the mean duration of follow-up was 6.4 ± 5.5 years (range, 2-19 years). Seventeen patients (68%) had a systemic disease and most of them were of hypertensive cases (48%). In 13 of the eyes (52%) inferior hemispheric quadrant and in 12 eyes (48%) superior hemispheric quadrant was found to be affected. The visual acuity at baseline was 1.08 ± 0.4 logMAR and it was 0.89 ± 0.5 logMAR at last visit (p&gt;0.05). According to the findings of FA, ischemic form was detected in 10 eyes at the time of diagnosis, and conversion to ischemic form occured in 3 cases during the follow-up. Laser photocoagulation was performed on ischemic lesions that were more than 10 disc areas. The complications due to HCRVO were as follows; macular edema in 12 eyes, intravitreal hemorrhage in 3 eyes, epiretinal membrane formation in 3 eyes, neovascular glaucoma in 3 eyes, optic atrophy in 2 eyes and regmatogenous retinal detachment in 1 eye. Macular grid laser for perfused macular edema was performed. Conclusion: The visual prognosis of the patients in the long-run was found to be associated with the presenting visual acuity and the development of a complication. Even a relative increase in the visual acuity after the follow-up was achieved, the increase was not statistically significan

A comparative study of the standart surgical technique versus mini-ıncision in the treatment of Carpal Tunnel Syndrome

Amaç: Median sinirin el bileği düzeyindeki tuzak nöropatisi olan karpal tünel sendromunun (KTS) sağaltımında farklı cerrahi teknikler bildirilmiştir. Bu çalışmada KTS olgularında 2 farklı cerrahi teknik kullanılarak uygulanan sağaltımın sonuçları karşılaştırılmıştır. Yöntem: ılk guruptaki 11 olgunun 12 eline standart teknik ile cerrahi dekompresyon uygulanmış, ikinci guruptaki 10 olgunun 12 elinde ise mini insizyon yöntemi uygulanmıştır. Bulgular: Postoperatif izlem süresi, komplikasyon sıklığı, klinik ve elektronörofizyolojik bulgular yönünden değerlendirildiğinde iki gurup arasında X ve Fisher'in exact testleri ile istatistiksel olarak anlamlı bir fark olmadığı belirlenmiştir. Sonuç: Bu sonuçlar bize KTS cerrahisinde kullanılan standart ve mini insizyon tekniklerinin birbirlerine üstünlüklerinin olmadığını düşündürmüştür.Aim: Various surgical treatment alternatives exist for carpal tunnel syndrome which is the the entrapment of the median nerve at the wrist level. In this study two different surgical techniques were comparatively evaluated in terms oftime needed forpostoperative follow-up, complications, clinical and electrodiagnostic improvement. Method: Surgical decompression utilising the standard technique was used in 12 hands of the 11 patients in the first group and the mini-incision technique was employed in 12 hands of the 10 patients in the second group. Results: No statistical difference in any one of the above mentioned parameters was found with the X2 and Fisher's exacttests. Conclusion: Thus, we conclude that neither of the two techniques utilised for carpal tunnel syndrome surgery can be considered superior to the other

New CagL amino acid polymorphism patterns of helicobacter pylori in peptic ulcer and non-ulcer dyspepsia

Background and Objectives: Helicobacter pylori infection is associated with chronic gastritis, ulcers, and gastric cancer. The H. pylori Type 4 secretion system (T4SS) translocates the CagA protein into host cells and plays an essential role in initiating gastric carcinogenesis. The CagL protein is a component of the T4SS. CagL amino acid polymorphisms are correlated with clinical outcomes. We aimed to study the association between CagL amino acid polymorphisms and peptic ulcer disease (PUD) and non-ulcer dyspepsia (NUD). Materials and Methods: A total of 99 patients (PUD, 46; NUD, 53) were enrolled and screened for H. pylori by qPCR from antrum biopsy samples. The amino acid polymorphisms of CagL were analyzed using DNA sequencing, followed by the MAFFT sequence alignment program to match the amino acid sequences. Results: Antrum biopsy samples from 70 out of 99 (70.7%) patients were found to be H. pylori DNA-positive. A positive band for cagL was detected in 42 out of 70 samples (PUD, 23; NUD, 19), and following this, these 42 samples were sequenced. In total, 27 different polymorphisms were determined. We determined three CagL amino acid polymorphism combinations, which were determined to be associated with PUD and NUD. Pattern 1 (K35/N122/V134/T175/R194/E210) was only detected in PUD patient samples and was related to a 1.35-fold risk (p = 0.02). Patterns 2 (V41/I134) and 3 (V41/K122/A171/I174) were found only in NUD patient samples and were linked to a 1.26-fold increased risk (p = 0.03). Conclusions: We observed three new patterns associated with PUD and NUD. Pattern 1 is related to PUD, and the other two patterns (Patterns 2 and 3) are related to NUD. The patterns that we identified include the remote polymorphisms of the CagL protein, which is a new approach. These patterns may help to understand the course of H. pylori infection.Istanbul Aydin University Scientific Research Projects Uni

A Comparison of Epidural Anesthesia without Motor Block Versus General Anesthesia for Percutaneous Nephrolithotomy

Objective:The study carried out to compare the operative parameters and stone clearance in patients who underwent percutaneous nephrolithotomy (PNL) under epidural anesthesia (EA) without motor block versus those who underwent PNL under general anesthesia (GA).Materials and Methods:We retrospectively reviewed 2 groups of patients who underwent PNL at our institute between January 2014 and September 2014. Group 1 consisted of 69 consecutive patients who underwent PNL under EA without motor block and group 2 consisted of 69 consecutive patients who underwent PNL under GA. Patients general characteristics, stone features, surgical parameters, duration of surgery, time spent in the operating room, postoperative analgesic requirements, complications, stone clearance rate and mean length of hospital stay were compared between the 2 groups.Results:The two groups were similar in terms of mean age, gender, stone size and previous surgery. Operative time, access site, mean access number, postoperative fever, drainage, mean hemoglobin drop, stone-free rate, duration of nephrostomy tube and length of hospitalization were also similar between the groups. The time spent in the operating room, blood transfusion rate and postoperative analgesic requirements in EA group were significantly lower than those in GA group.Conclusion:PNL under EA without motor block is as effective and safe as PNL under GA and it offers some advantages as with lower parenteral analgesic requirements, lower transfusion rates and lesser usage of operation room

Curative Chemoradiotherapy of Primary Pancreatic Lymphoma with Vertebral Metastasis: Palliation of Persistent Biliary Stricture by Roux-en-Y Hepaticojejunostomy

Primary pancreatic lymphoma (PPL) is a rare tumor that usually presents with the clinical picture of advanced adenocarcinoma but has a much better prognosis. A 38-year-old man was referred after percutaneous transhepatic external biliary drainage for obstructive jaundice. Abdominal magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography had revealed a 5-cm pancreatic head mass that caused biliary tract dilation. Computed tomography angiography showed that the mass encased the celiac trunk as well as the common hepatic and splenic arteries. MRI also revealed a metastatic lesion at the third lumbar vertebra. Serum carcinoembryonic antigen and carbohydrate antigen 19-9 levels were within normal range. The initial diagnosis was inoperable pancreatic adenocarcinoma; however, Tru-Cut pancreatic biopsy showed a large B cell lymphoma. After 6 sessions of chemotherapy and 21 sessions of radiotherapy, both the pancreatic mass and the vertebral metastasis had disappeared. However, he had persistent distal common bile duct stricture that could not be negotiated by either the endoscopic or percutaneous route. A Roux-en-Y hepaticojejunostomy was performed. The patient stayed alive without recurrence for 52 months after the initial diagnosis and 45 months after completion of oncologic treatment. In conclusion, a large pancreatic mass with grossly involved peripancreatic lymph nodes, without ascites, liver or splenic metastasis, should alert the clinician to the possibility of PPL. Cure is possible by chemoradiotherapy even in the presence of vertebral metastasis. Persistent stricture in the distal common bile duct may require a biliodigestive anastomosis