63 research outputs found

    Effect of air-jet texturing on adhesion behaviour of technical polyester yarns to rubber

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    Air-jet texturing of technical polyester yarns was performed in order to improve its adhesion to rubber. The air-jet texturing parameters were selected with great care to minimize the mechanical loss. H-adhesion tests were used to characterize the adhesion of the yarns to rubber. A significant increase in the adhesion of dimensionally stable polyethylene terephthalate yarn, textured with an overfeed level of 15% (DSPET15), was recorded, while a decrease in the adhesion of high tenacity polyethylene terephthalate (HTPET) yarn was observed for all overfeed levels. The effects of air-jet texturing on the adhesion of technical polyester yarns were discussed in terms of changes in the yarn geometry and changes on the single fiber surfaces. Changes in the yarn geometry were investigated by optical microscopy studies, while changes on the fiber surface were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM) studies. It was observed that air-jet texturing alters both the yarn geometry and the single fiber surfaces, leading to a change in the adhesion to rubber

    3D-printed composite bone bricks for large bone tissue applications

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    This study investigates the use of low cost, customizable, biodegradable, polymer-ceramic composite porous structures (bone bricks) for large bone tissue regeneration. Different ceramic materials (hydroxyapatite (HA), β-tri-calcium phosphate (TCP) and Bioglass (45S5) were mixed with poly-ε-caprolactone (PCL). Bone bricks with different material compositions were produced using an extrusion-based additive manufacturing system. Produced bone bricks were morphologically and mechanically assessed. Results allowed to establish a correlation between scaffolds architecture and material composition and scaffolds performance. Reinforced scaffolds showed improved mechanical properties. Best mechanical properties were obtained with PCL/TCP bone bricks and topologies based on 38 double zig zag filaments and 14 spirals

    Investigation of the Distribution of Fetal Nasal Bone Percentile Values in First-Trimester Fetal Anomaly Screening

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    INTRODUCTION: We aim to determine the fetal nasal bone length (NBL) percentile values that can be used in the prediction of the fetal anomaly at 11-14 weeks of gestation in a low-risk population. METHODS: Our prospective and cross-sectional study included four hundred and eighty-six singleton pregnancies who applied for the first-trimester aneuploidy screening test at 11-14 weeks of gestation. We excluded pregnant women with fetal structural or chromosomal anomaly, nuchal translucency >3mm, an absent nasal bone, and in utero fetal death. Reference and percentile values of the NBL were calculated separately for 11,12,13,and 14. gestational weeks. RESULTS: Standard NBL measurements were performed in 486 pregnancies according to inclusion and exclusion criteria. Median NBL values were computed for each gestational age (GA), for 11,12,13 and 14. weeks of gestation was found 1.6mm (range=1.1-2.5), 1.8mm (range=1.1-3.0), 2.0mm (range=1.4-3.1), and 2.2mm (range=1.7-2.8), respectively. A positive significant correlation was found between NBL and the crown-rump length (CRL) (NBL (mm) = [0.02xCRL(mm)] + 0.73, r=.483; p<.001). The 5th percentile of NBL for GA was calculated, for 11,12, 13, and 14. weeks of gestation was found 1.2mm,1.4mm,1.5mm, and 1.7mm respectively. DISCUSSION AND CONCLUSION: We revealed the reference value of NBL for each gestational week in the first trimester of the low-risk population. The data obtained in our study can be used in the screening of genetic syndromes, especially Down syndrome, associated with nasal bone hypoplasia. Our reference value of NBL for the first trimester in singleton pregnancy varies from both previous racial and ethnic groups studies, and other Turkish studies

    Detection of serum MMP-7 and MMP-9 in cholangiocarcinoma patients: evaluation of diagnostic accuracy

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    <p>Abstract</p> <p>Background</p> <p>Cholangiocarcinoma is an aggressive tumor with a tendency for local invasion and distant metastases. Timely diagnosis is very important because surgical resection (R0) remains the only hope for a cure. However, at present, there is no available tumor marker that can differentiate cholangiocarcinoma from benign bile duct disease. Previous studies have demonstrated that matrix metalloproteinase (MMP)-7 and MMP-9 are frequently expressed in cholangiocarcinoma specimens.</p> <p>Methods</p> <p>This study was designed to determine whether the serum levels of MMP-7 and MMP-9 can discriminate cholangiocarcinoma patients from benign biliary tract disease patients in comparison to carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). We measured the level of CEA, CA19-9, MMP-7 and MMP-9 in the serum of 44 cholangiocarcinoma and 36 benign biliary tract diseases patients.</p> <p>Results</p> <p>Among the serum levels of CEA, CA19-9, MMP-7 and MMP-9, only the serum MMP-7 level was significantly higher in the patients with cholangiocarcinoma (8.9 ± 3.43 ng/ml) compared to benign biliary tract disease patients (5.9 ± 3.03 ng/ml) (<it>p </it>< 0.001). An receiver operating characteristic (ROC) curve analysis revealed that the detection of the serum MMP-7 level is reasonably accurate in differentiating cholangiocarcinoma from benign biliary tract disease patients (area under curve = 0.73; 95% CI = 0.614–0.848). While the areas under the curve of the ROC curves for CEA, CA19-9 and MMP-9 were 0.63 (95% CI = 0.501–0.760), 0.63 (95% CI = 0.491–0.761) and 0.59 (95% CI = 0.455–0.722), respectively.</p> <p>Conclusion</p> <p>Serum MMP-7 appears to be a valuable diagnostic marker in the discrimination of cholangiocarcinoma from benign biliary tract disease. Further prospective studies for serum MMP-7 measurement should be carried out to further investigate the potential of this molecule as a biomarker of cholangiocarcinoma.</p

    Preterm premature rupture of membrane assessment via transperineal ultrasonography: a diagnostic accuracy study

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    Objective: The objective of this study is to evaluate diagnostic accuracy of transperineal ultrasound assessment compared to speculum examination by using placental alfa-microglobulin (PAMG)-1 tests as reference.Methods: This was a prospective observational study conducted in Ankara University Hospital. Women with early and late preterm pregnancies with suspected rupture of membranes, i.e. women with a complaint of fluid leakage (105 in total) were enrolled. Prior to speculum examination, sagittal and transverse plane views of the fornices and cervix were obtained via transperineal ultrasonography and images were stored. Then the speculum examination for amniotic fluid pooling was performed. Definite diagnoses were made with PAGM-1 assays. After collection of the data, ultrasound images were analyzed by an observer blind to physical examination findings. Hypoechogenic fluid appearance around the cervix and in the fornices was considered positive for preterm premature rupture of membranes (PPROM). Results of physical and ultrasound examination were compared with PAMG-1 test as a reference method. The diagnostic performance of transperineal ultrasound was tested with accuracy parameters and receiver-operating characteristics (ROC) curves. Inter-rater reliability was analyzed with Cohen's kappa.Results: In total, 103 pregnant women were evaluated. The prevalence of PPROM in our study population was 43.14%. At a 5mm diagnostic threshold, the sensitivity and specificity values of transperineal assessment were 95.45% (95% CI: 84.50-99.31%) and 96.55% (95% CI: 88.07-99.48%), respectively, and they were comparable with speculum examination in a population of preterm pregnant women with suspected PPROM (p>0.05). Interobserver reliability analysis with Cohen's kappa has shown good very good agreement with the kappa value of 0.93 (95% CI 0.87-1.00).Conclusions: Transperineal ultrasonography is a novel method that can be used to assess vaginal pooling of amniotic fluid. Ultrasonography offers similar sensitivity and specificity compared with speculum examination and it is non-invasive
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