Cerebral hemodynamics in patients with cirrhosis

Background/Aims: Cirrhosis causes a decrease in cerebral blood flow because of a hyperdynamic circulatory state. We aimed to study the cerebral hemodynamic parameters in patients with decompensated cirrhosis and their relationship to the Child-Pugh and Model for End-Stage Liver Disease (MELD) scores. Materials and Methods: We used transcranial Doppler to investigate the cerebral hemodynamic parameters, namely the mean flow velocity of the middle cerebral artery, pulsatility index (PI), and resistive index (RI), in 50 patients who had decompensated cirrhosis and in a control group of 50 healthy people. We also investigated their relationship to the Child-Pugh and MELD scores. Results: Patients with cirrhosis had a lower mean flow velocity than those in the control group. Further, patients with cirrhosis had higher PI and RI values. There was a positive correlation between PI and the Child-Pugh score. In addition, there was a positive correlation among PI, RI, and the MELD score. The RI values of patients with ascites were higher than those of patients without ascites. Conclusion: Cerebral autoregulation might be impaired in patients with cirrhosis. Cerebral resistance proportionally increases to disease severity. There was a positive correlation among PI, RI, and MELD scores, which means that transcranial Doppler might be useful not only in the follow-up of the severity of the disease but also in determining the survival of these patients. © Copyright 2016 by The Turkish Society of Gastroenterology

Monitoring micro-damage accumulation based on reduction in elastic properties using fiber bragg grating sensors, and acoustic emission and thermography methods in fiber reinforced polymeric composites

Laminated Composite Structures (LCS) have been used increasingly in recent years in engineering applications such as aircraft and shipbuilding. However, it is important to note that despite the constant increase in the usage of LCSs, a number of certain aspects need to be investigated in detail. These aspects can be summarized in two different topics: the effect of different micro-damage types on LCSs and novel test methods for the measurement of certain mechanical properties. Here, to touch on these two issues, we investigate micro-damage accumulation and its effects on elastic constants of the laminated composite as well as we introduce a Finite Element Analysis (FEA) of a possible test method to calculate certain mechanical properties of thin-laminated composites. Unlike metals, LCSs can develop different types of micro-damage under load. These different types of micro-damage play a critical role in the failure of LCSs. Once initiation and accumulation of different types of micro-damage are understood, an adequate understanding of LCSs under operational loads can be established. This understanding results in the prediction of possible failure time of LCSs and usage of a number of elastic constants as a micro-damage monitoring index. For that purpose, we present an experimental study on the monitoring of the reduction in Poisson's ratio coupled with micro-damage initiation and accumulation. Poisson's ratio is monitored with a novel an embedded-biaxial Fiber Bragg Grating (FBG) sensor during the static tensile test of composite coupons. Accumulation of different types of micro-damage are monitored with Acoustic Emission (AE) set-up. It is seen that as Poisson's ratio reduces under tensile loading, composite coupons emit a higher number of acoustic waves due to the micro-damage formation. It is also demonstrated that reduction in in-plane shear modulus under in-plane shear loading is due to micro-damage accumulation. For this purpose, two different fiber reinforcement, S-glass and E-glass, are chosen to produce laminated composites. The total amount of micro-damage incurred as well as the average temperature change measured by thermography are higher for the E-glass reinforced LCS. Under the applied in-plane shear load, a significant reduction in inplane shear modulus is observed both for the E-glass and S-glass-reinforced LCS, where the E-glass reinforced LCS shows a greater reduction. In addition, a FEA of Lamb wave propagation in thin-laminated composites is also performed. The performed FEA is a numerical simulation of a novel, nontime-consuming, non-destructive evaluation method for thin-laminated composite structures to calculate the components of stiffness matrix and laminate elastic properties. For that purpose, the group velocities of A0 and S0 modes of Lamb wave are measured on a transversely isotropic thin-laminate. Then, these group velocities are used in Christoffel's equation to calculate the components of stiffness matrix. In turn, the components of stiffness matrix are used in an inverse formulation to calculate thin-laminate elastic constants

Manufacturing of microcapsules with liquid core and their self-healing performance in epoxy for resin transfer molding

Microcapsules with different active core materials have been receiving a great deal of attention for developing polymer based materials with selfhealing abilities. The self-healing ability is crucial in particular for matrix materials having brittle nature such as epoxy resin. In order for abstaining from an abrupt failure of structural brittle manner polymeric materials, microcapsules can be used excellently as a viable repair agent. In this work, we present a study on the catalyst-free microcapsule based self-healing system. Microcapsules were produced by the insitu polymerization of urea-formaldehyde at the dispersed phase-water interface. Each microcapsule batches were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analyser (TGA), Di erential Scanning Calorimetry (DSC). Characteristic peaks of urea-formaldehyde shell, core components; DGEBA, and PhCl was seen in the Mid- IR region. Characteristic thermal decomposition temperature of urea-formaldehyde wall material and DBEBA which is the main microcapsule content were determined from the TGA trace. In addition to the given thermal and spectral characterization tools, optic microscope and SEM images also ensure the formation of liquid- lled microcapsules. Although the microcapsules showed brittle behavior during the processing such as drying and sieving, incorporation of microcapsules into the epoxy matrix was achieved successfully. The healing characteristic of epoxy-microcapsule composite was assessed by the Tapered Double Cantilever Beam (TDCB) specimen at the mode-I crack opening fashion. Besides microcapsule-epoxy composite system showed a moderate healing efficiency, a significant increase in mode-I fracture toughness value was observed. Three point bending experiment was also conducted on the microcapsule-epoxy composite. It was found that microcapsules drastically decrease the flexure strength of questioned host material

Effects of Hot Isostatic Pressing and Heat Treatments on Structural and Corrosion Properties of Direct Metal Laser Sintered Parts

Purpose – This paper aims to investigate the effects of various heat treatments on microstructure, hardness, porosity and corrosion properties of the parts. Design/methodology/approach – Hot isostatic pressing (HIP) process, various heat treatments and their combinations were applied to the AlSi10Mg parts produced by direct laser metal sintering (DMLS). Findings – It has been found that the HIP process, which is a post-processing process, reduces the amount of porosity in DMLS-AlSi10Mg material, thus improves corrosion resistance significantly. Originality/value – In this study, the HIP process and subsequent T6 heat treatments were applied to AlSi10Mg parts produced by the DMLS technique. The study aims to increase the corrosion resistance of AlSi10Mg parts by reducing porosity with the HIP process and by altering the microstructure with the T6 process

Solitary Fibrous Tumor of the Supraclavicular Region

Solitary fibrous tumors of the head and neck are extremely rare, slow-growing, and generally asymptomatic benign neoplasms. To the best of our knowledge, only 153 cases of solitary fibrous tumors in the head and neck have been previously reported in the English literature until 2010. However, none has been in the supraclavicular region. Herein, we report a case of solitary fibrous tumor arising from the supraclavicular region. Characteristics, differential diagnosis, and treatment of the disease were also summarized

Giant arachnoid granulation in a patient with benign intracranial hypertension (2009: 1b)

We report magnetic resonance (MR), computed tomography (CT) and angiographic imaging of an unusual giant arachnoid granulation 7(GAG) in the superior sagittal sinus in a man with headache and vertigo. Intrasinus pressure measurements revealed a significant pressure gradient across the lesion. MR imaging is useful to identify GAG and dural sinus thrombosis, whereas dural sinus pressure measurement in certain cases of GAGs can be used to evaluate the lesion as the cause of the patient's symptoms

Böbrek nakli alıcısında splenik arter anevrizması

In this article, we present the first case of SAA (Splenic Artery Aneurysm) in a kidney transplantation recipient, which was incidentally detected during the preparation of the transplantation and successfully treated. A 25-mm SAA was detected at kidney transplant recipient during the preparation examination by abdominal ultrasonography. Splenic artery ligation and aneurysmectomy was performed before the transplantation. Intraoperative Doppler ultrasonography revealed that there were no abnormalities of the spleen blood supply. During the first month of follow-up, the patient remained asymptomatic and laboratory investigations revealed no abnormalities. Selective ligation and resection of SAAs combined with spleen preservation is a safe treatment modality for selected cases with favorable short and long-term results, allowing the permanent treatment of the SAA, while preserving the splenic function.Bu yazıda, böbrek nakli alıcısında, nakil hazırlığı sırasında tesadüfen tespit edilen ve başarıyla tedavi edilen ilk SAA (Splenik Arter Anevrizması) vakasını sunuyoruz. Karın ultrasonografi ile yapılan hazırlık incelemesinde böbrek nakli alıcılarında 25 mm SAA saptandı. Nakil öncesi splenik arter ligasyonu ve anevrizmektomi yapıldı. İntraoperatif Doppler ultrasonografi ile dalak kan akışında herhangi bir anormallik olmadığı gösterildi. Takibin ilk ayında hasta asemptomatik kaldı ve laboratuvar incelemelerinde herhangi bir anormallik görülmedi. Dalak korunarak SAA'ların seçici ligasyonu ve rezeksiyonu, splenik fonksiyonu korurken SAA'nın kalıcı tedavisine izin veren, olumlu kısa ve uzun vadeli sonuçları olan seçilmiş vakalar için güvenli bir tedavi yöntemidir

A Review of 2625 Isolated Hydrocele Cases in Children

Introduction: Inguinal hernias and hydroceles are the most frequently performed procedures in pediatric surgery departments. In this study, we aimed to define the spontaneous regression rate in different types of  hydroceles, the regression age, the timing of surgery, and the optimal treatment approaches for each hydrocele type in cases with isolated hydroceles in children.Material &Methods: This historical cohort study included 2625 patients which were admitted between January 2004 and December 2012. The hydroceles were classified as: ‘non-communicating hydroceles’, ‘communicating hydroceles’, ‘spermatic cord hydroceles’ and ‘abdomino-scrotal hydroceles’ (ASH). Patients were divided into two groups with regard to their ages at diagnosis as follows: those presenting in the newborn period and before 24 months of age (Younger– Group 1) and those presenting after 24 months of age (Older – Group 2). Determining the type of isolated hydrocele, the decision making for follow-up or surgery, and the follow-up period were conducted by 7 attending pediatric surgeons and 6 residents. Results: In Group 1, 93% of 1086 non-communicating hydroceles, 40% of 158 cord hydroceles, and 15% of 34 communicating hydroceles resolved during the follow-up, and the remaining patients with each type of hydrocele underwent surgery. In Group 2, 8.7% of 183 non-communicating hydroceles resolved during the follow-up.Conclusion: The primary treatment of patients with isolated hydrocele should be decided regarding the type of hydrocele, along with age at admission, and accordingly, conservative or surgical treatment should be considered

The Effect of Nasal Functions on the Integrity of Grafts after Myringoplasty

Objective:We aimed to evaluate the effects of nasal functions for the integrity of grafts after myringoplasty.Methods:In our study 78 patients who underwent myringoplasty operation between 2011-2013 were included. Group I was defined as the group with an intact tympanic membrane following surgery. Group II was defined as the group with a tympanic membrane perforation following surgery. Group I consisted of 44 and Group II consisted of 34 patients. Subjective and objective measurements of nasal functions, Eustachian tube function (ETF), and allergic status were performed using nasal obstruction symptom evaluation (NOSE) scale, visual analog scale (VAS), and the score for allergic rhinitis (SFAR) questionnaires and acoustic rhinometry and saccharin test. It was investigated whether there was any difference between these two groups in terms of these parameters.Results:There was statistically no significant difference between groups according to the age, sex and the presence of tubal dysfunction and allergic rhinitis (p>0.05). In the group of intact tympanic membranes, the likelihood of right ear being the operated one was significantly higher compared to the group of myringoplasty failures (p=0.037). The VAS and NOSE scales did not show any significant difference between groups in terms of successful outcome of myringoplasty (p>0.05). The nasal congestion index (NCI) and the mucociliary clearance (MCC) did not show any significant difference between groups in terms of successful outcome of myringoplasty (p>0.05).Conclusion:This study has shown that nasal functions measured by objective and subjective methods had no effects on the success of myringoplasty

Monitoring the damage state of fiber reinforced composites using an FBG network for failure prediction

A structural health monitoring (SHM) study of biaxial glass fibre-reinforced epoxy matrix composites under a constant, high strain uniaxial fatigue loading is performed using fibre Bragg grating (FBG) optical sensors embedded in composites at various locations to monitor the evolution of local strains, thereby understanding the damage mechanisms. Concurrently, the temperature changes of the samples during the fatigue test have also been monitored at the same locations. Close to fracture, significant variations in local temperatures and strains are observed, and it is shown that the variations in temperature and strain can be used to predict imminent fracture. It is noted that the latter information cannot be obtained using external strain gages, which underlines the importance of the tracking of local strains internally