The association between TAPSE and right atrial contractile strain

BACKGROUND: In the descending arm of tricuspid annular plane systolic excursion (TAPSE) there is a notch formation which corresponds to the contractile phase of the atrial strain curve. Theoretically, this notch formation stands for atrial contraction. AIMS: We aim to characterize the notch formation on the TAPSE, the predictors of its existence, its relationship with the right ventricle and right atrial strain (RAS) parameters. METHODS: Retrospectively selected 240 patients were investigated for the determinants of the notch formation on TAPSE and the relation between RAS and TAPSE. RAS was analyzed using 2D speckle tracking in a dedicated mode for atrial analysis and reported separately for the reservoir, conduit, and contractile phases. RESULTS: 71.7% (n = 172) of patients had the notch formation on the TAPSE and 70.4% (n = 169) had a normal value of right atrial contractile strain (RASct). Most of the patients with a notch formation also had preserved RASct (95.9%; P <0.001). In multivariable analysis, RASct (odds ratio [OR], 1.45; 95% confidence interval [CI]: 1.13­­‒1.77; P = 0.020) remained significant with the notch formation. Receiver operator characteristic (ROC) analysis demonstrated that a RASct of ‒19% was found as a cut-off for presence of notch formation. ROC area was 0.897 (95% CI 0.844–0.951; P <0.001). CONCLUSIONS: The changes in TAPSE configuration represents the changes in atrial contractile phase. The descending arm of the TAPSE indicates the RASct as whether it is preserved or not. The notch formation persists if the RASct is above ‒19%. So, an easier, more applicable, and more effortless tool TAPSE can be used as an indicator of atrial contractile phase by its configuration in daily routine

Live Cell Imaging of Bone Marrow Stromal Cells on Nano-pitted and Polished Titanium Surfaces: A Micro-Incubator in vitro Approach

Current orthopedic implants are not conducive for optimal integration of the biomaterial with newly-formed tissue (osseointegration) inside a patient’s body. In this study, medical-rade Ti-6Al-4V was used as a substrate due to its biocompatibility and ability to facilitate cellular adhesion and proliferation. Live cell imaging was conducted on bone marrow stromal cells, genetically modified to express the green fluorescent protein (GFP), from the 24-96 hours growth period, with the first 24 hours of growth being held inside a lab-scale incubator. Periodic images were recorded on nanopitted anodized and polished Ti-6Al-4V substrates to study how substratestiffness influences adhesion and proliferation. Collected images were analyzed for mitosis, adhesion, and filopodia-stretchability using ImageJ, an image processing program. Images were enhanced in order to perform cell counts at 24, 48, 72, and 96 hours of growth. Continuous recordings were produced to account for the number of mitosis occurrences and cellular migration on each of the substrates. Based on the conducted experiments, it appears that polished Ti-6Al-4V has a higher cell adherence than “nanopitted” anodized surface and an improved rate of proliferation which may be because the cells once adhered on the nano-pitted surface have less ability to detach in-order to undergo mitosis.https://engagedscholarship.csuohio.edu/u_poster_2014/1004/thumbnail.jp

Experımental Comparıson Of Pullout Propertıes Of Varıous Pedıcle Screw Systems For Osteoporotıcs Cases

Bu çalışmada omurga cerrahisinde kullanılan pedikül vidaların farklı koşullardaki çekip çıkarma performansları incelenmiştir. Normal, çimento takviyeli normal, çimento takviyeli kanüllü ve yeni geliştirilen ucu genişleyen pedikül vidaların; başlangıç durumu, toggling sonrası ve suni füzyon sonrası çekip çıkarma dayanımları belirlenmiştir. Çalışmada kullanılan ucu genişleyen pedikül vidalar, yeni geliştirilmiş olup bu kapsamda bir çalışmaya konu olmamıştır. Bunun yanında suni füzyon işlemi, literatüre yeni kazandırılmış bir yöntem olarak, füzyon işleminin canlı doku yerine sentetik köpükler ile modellenmesine imkan vermektedir. Derece 10 ve Derece 40 sentetik köpükler ile dana omurlarının deney malzemesi olarak kullanıldığı çalışmada; takviye malzemesi olarak PMMA tercih edilmiştir. Derece 40 sentetik köpüklere sabitlenen pedikül vidaların dayanım değerlerinin, üç durumda da Derece 10 köpüklere sabitlenenlere göre beklendiği gibi daha yüksek olduğu tespit edilmiştir. Vücut hareketleri neticesinde vida üzerine gelen yüklerin etkisinin incelendiği toggling deneyleri sonunda dayanım değerlerinin başlangıç durumuna göre azaldığı görülmüştür. Diğer yandan suni füzyon işlemi ile pedikül vidaların dayanım değerlerinin belirgin biçimde yükseldiği belirlenmiştir. Çimento takviyesinin pedikül vidalarda dayanım değerlerini önemli ölçüde artırdığı görülürken, ucu genişleyen pedikül vidaların göstermiş olduğu başarım ile çimento takviyeli pedikül vidalara iyi bir alternatif olabileceği ortaya konulmuştur. Özellikle osteoporotik vakalarda düşük kemik mineral yoğunluğu nedeniyle vidaların tutunma kabiliyetlerinin düşük olması, zararlı etkilerine rağmen çimento takviye malzemelerinin kullanımını gerekli hale getirmektedir. Yeni geliştirilen ucu genişleyen pedikül vidaların bu noktada önemli bir ihtiyacı gidermesi beklenmektedir.Pullout strengths of pedicle screws used in spine surgery in various conditions were investigated in this study. The pullout strengths of solid core, augmented solid core, augmented cannulated and novel expandable pedicle screws for initial state, after toggling and postfusion were determined. Expandable pedicle screw used in this study was designed newly (designed before this study) and it has not been subjected to a study before. Besides, the artificial fusion process, as included to the literature for the first time, makes it possible that fusion may be provided in polyurethane foams artificially instead of living tissue. Grade 10 and Grade 40 polyurethane foams and bovine vertebra were used as a test material and PMMA was selected as an augmentation material in study. Strengths of pedicle screws, instrumented to the Grade 40 foams, are higher than ones instrumented to Grade 10 foams as expected for all test conditions. After the toggling tests, in which the loads weighed on pedicle screws by motion of body were investigated, the pullout strengths decreased when they were compared with initial state condition. On the other hand, it was determined that the pullout values increased significantly by artificial fusion process. While the pullout strengths increased considerably by augmentation, it was theorized that the novel expandable pedicle screw may be a good alternative to the augmented pedicle screws. Especially in osteoporotic cases, being the holding capability of pedicle screws lower because of inadequate bone mineral density, it makes the use of cement necessary due to its noxious effect in spine surgery. It is expected that the novel expandable pedicle screws will be a good solution and also fulfill the need at this point

Comparison of biomechanical properties of implant systems used in treatment of proximal femur fractures

Various implant systems used in treatment of proximal femur fractures were investigated comparatively in this study. The intertrochanteric fractures prepared over fourth generation synthetic femur models were fixed with DHS, PFNA, Talon and Veronail implant systems. The models were positioned normally as in vivo by using polyurethane foam dying process. Test samples were subjected to the compression loading with crosshead speed controlled. The loads and displacements corresponding to the loads were recorded during the test and the graphs of displacements versus loads were obtained after test completed. In order to determine that whether the displacement values were statistically significant or not, Student T tests were performed. The physical changing in test samples were observed simultaneously by taking snapshot photo during the test. Whereas the DHS which is one of the extramedullary screw system in this study had the lowest load, they had the highest displacement values also they were concluded as the unsuccessful implant system as compared with others. The Talon implant system had the highest biomechanical properties, PFNA and Veronail systems followed this system. The displacement values of one lag screwed PFNA and two lags screwed Veronail are statistically insignificant and the changing in fracture lines verified this phenomenon. It is concluded that the Talon and PFNA implant systems would be used in treatment of intertrochanteric fractures successfully due to their higher biomechanical properties and clinical findings

Investigation on manufacturability of bone plates used in humerus fractures by additive manufacturing method

In this study, the manufacturability of Ti6Al4V titanium alloyed bone plates used in fracture of humerus by additive manufacturing method was surveyed. In order to determine ideal production conditions for additive manufacturing method, the effect of building direction and preheating on mechanical properties was investigated. All the samples were manufactured by using same process parameters and heat treated in same conditions after production. The samples were manufactured on four different building directions (vertical, horizontal, 1x45, 2x45) and two preheating conditions (0 and 200 degrees C). After the heat treatment process completed for stress relieving, they were tested in axial tensile testing and three-point bending testing statically and dynamically. While, the orientation did not make a significant effect on mechanical properties, the strength of samples was affected negatively with preheating process. However, it was seen that the ductility and toughness of samples increased via the preheating process. The sample manufactured with preheating in vertical direction had the highest mechanical properties when compared to the other samples. Thus, the bone plates were manufactured on this condition and heat treated, then they were tested in four-point bending testing according to the ASTM F382. It was concluded that the bone plates manufactured by additive manufacturing method had better bending strength and fatigue behavior. They may be an alternative choice for fixation treatments of humerus fractures in clinical applications

Effects of ageing heat treatment on mechanical properties of sic and al2o3 particles reinforced aluminum alloy composites

Birçok sanayi sektöründe geleneksel malzemelerin yerine kullanılmaya başlayan kompozit malzemelerin, farklı koşullarda sahip oldukları mekanik özelliklerin bilinmesi son derece önemlidir. Bu çalışmada seramik takviyeli yaşlandırılabilir 7xxx serisi alüminyum alaşımı esaslı kompozit malzemelerin, sıcak presleme yöntemi kullanılarak üretimleri yapılmıştır. Daha sonra farklı yaşlandırma koşullarında numunelerin mekanik özellikleri belirlenmiştir. Numunelerde ana yapı olarak Al-5Zn-3,5Cu-2,5Mg alaşımı, takviye elemanı olarak SiC ve Al2O3 seramikleri kullanılmıştır. Alaşım, SiC, Al2O3 ve karma takviyeli olmak üzere farklı bileşimlerde toplam 12 adet numune türü hazırlanmıştır. Numuneler üretildikten sonra, numunelere ilk olarak çözeltiye alma ve su verme işlemleri, daha sonra ise doğal ve yapay olmak üzere farklı koşullarda yaşlandırma işlemleri uygulanmıştır. Yaşlandırma işlemleri süresince numunelerin sertlik değişimleri belirlenmiştir. Buna ek olarak, her koşul için elde edilen en yüksek sertlik değerlerinde; üç nokta eğme deneyi ile numunelerin akma dayanımları belirlenmiştir. Ayrıca, numunelerin iç yapıları, ışık ve taramalı elektron mikroskopları yardımıyla incelenmiştir. Çalışmanın sonunda, doğal yaşlandırma işleminde yaşlandırma süresine bağlı olarak sertlik değerlerinin başlangıçta yükseldiği fakat daha sonra büyük ölçüde kararlı davranış sergilediği görülmüştür. Yapay yaşlandırma işlemlerinde ise numuneler yaşlandırma sıcaklığına göre farklı sonuçlar sergilerken, en iyi sonuçlar %20 SiC takviyeli numunelerde elde edilmiştir. Eğme deneylerinde ise, yüksek sertlik değerlerinde genellikle düşük dayanım değerleri elde edilmiştir. Bu çalışmayla yaşlandırma işlemlerinin farklı bileşimlerdeki numunelerin mekanik özellikleri üzerinde oluşturduğu etkiler belirlenmiştir.Composite materials, one group of advanced materials, are widely used in various applications. Particularly in structural applications, determination of the mechanical properties of composite materials is very crucial. In this study, the effect of main aging parameters on the mechanical properties of ceramic reinforced aluminum alloy composites produced by hot pressing method was investigated. Al-5Zn-3,5Cu-2,5Mg alloy as matrix and SiC and Al2O3 ceramics materials as reinforcement were used in the production of samples. Totally, 12 compositions were prepared as alloy, composites reinforced with SiC, Al2O3 and hybrid in different reinforcement ratio. After the production of samples, firstly they were solutionized, and then both the artificial and natural aging processes were carried out. The hardness behaviors of samples were determined during the aging processes. Additionally, the yield strength of the samples having maximum hardness for different aging conditions was determined using three point bending experiments. Besides the microstructure of samples were observed by using optical and scanning electron microscopes. According to the experimental results in the naturally aged composites the hardness values depending the aging time arose in the beginning of the process but then it was seen that they had a stable behavior substantially. Furthermore in the artificially aged composites the different hardness behaviors were determined depend on different aging temperatures. Among the investigated samples, the composites with %20 SiC showed the best mechanical properties

Toggling effect on pullout performance of pedicle screws: Review

Screw loosening in spine surgery is a clinical complication in patients with poor bone quality. Pedicle screws are subjected to bending moments and axial loads that may cause toggling during daily movements of spine. The purpose of this study was to assess the previous studies related to toggling effect on pullout performance of pedicle screws by surveying the whole literature and to provide some discussion for new studies about pullout performance of pedicle screws after toggling. The search was performed by combining terms of pedicle screw, toggling, screw loosening, fatigue, cyclic loading, and pullout. The retrieved articles dealing with determined terms and also their references were reviewed. Some of these articles were eliminated after review process. Toggling was determined to be crucial for the stabilization performance of pedicle screw because the loosening mechanism of screws was affected directly by cyclic loading. The toggling or cyclic loading affected the holding capacity of pedicle screws negatively, and the possibility of loosening or failure problem for pedicle screws increased with cyclic loading magnitude. Loading conditions, screw properties, test medium, level of spinal region, and cement usage were determined by many researchers as the most important parameters affecting the toggling performance as well as the pullout strength of pedicle screws. The pullout strength of pedicle screws generally decreased with cyclic loading. The parameters of cyclic loading were fairly important for pullout performance of pedicle screws. Screw properties and cement augmentation had critical effects on the stability of screws under cyclic loading, as well

Comparison of polymerase chain reaction (PCR) and enzyme-immunoassay (EIR) for the diagnosis of Chlamydia trachomatis infections in symptomatic and asymptomatic females

Semptomatik infeksiyonu olan 49 kadın hasta ile asemptomatik 42 kadında polimeraz zincir reaksiyonu (PCR) (Genomed) ve enzim immunoassay (EİA) (Antigen Chiamydia Shield Diag. (FCHL 100) yöntemi kullanılarak endoservikal örneklerden Chiamydia infeksiyonu araştırılmıştır. Semptomatik kadınlardan alman 49 örneğin altısında (% 12.2) PCR, dördünde (% 8.16) EİA yöntemi ile Chiamydia trachomatis pozitifliği bulunurken; asemptomatik kadınlardan alınan 42 örneğin dördünde (% 9.52) PCR, ikisinde (% 4.76) EİA yöntemi ile C. trachomatis pozitifliği bulunmuştur. Tüm olgularda Chiamydia pozitifliği 10 (% 10.8) olarak saptanmıştır. Semptomatik ve asemptomatik kadınlar arasında Chiamydia pozitifliği açısından istatistiksel anlamlı fark (p > 0.9) saptanmamış ve asemptomatik kadınların da Chiamydia yönünden taranmasının gerekli olduğu sonucuna varılmıştır. PCR esas alındığında ElA'da duyarlık % 60, özgüllük % 100 olarak bulunmuştur. Pozitif prediktif değer % 100, negatif prediktif değer % 95.6 olarak saptanmıştır. Çalışma sonucunda PCR'nun EİA yöntemine üstünlüğü gösterilmiş ve Chiamydia infeksiyonlarının tanısında PCR'nun önemi tartışılmıştır.Fourty-nine patients and 42 asymptomatic women were screened for endocervical Chiamydia trachomatis infection using polymerase chain reaction (PCR) (Genomed) and enzyme immuno-assay (EIA) (Antigen Chiamydia Shield Diag FCHL). Six of the 49 samples (12.2 %) and four of 49 (8.16%) obtained from symptomatic patients; four of the 42 samples (9.52 %) and two of 42 samples (4.76'%) pertaining to asymptomatic women were positive for Chiamydia trachomatis by PCR and EIA. The overall positivity rate was 10.8 % by PCR. There was no significant difference between the asymptomatic women and symptomatic patients in relation to chlamydial positivity (p > 0.9). Showing that screening asymptomatic women for chlamydial infection is important. The sensitivity of PCR was 100 % and of EIA 60 % (Positive predictive value is 100 %, negativ predictive value is 95.6 %. As a result of this study the PCR appeared to be more sensitive than EIA in detecting Ç trachomatis in the cervices of women with symptomatic and asymptomatic infection