41 research outputs found
The Value of Serum Biomarkers (Bc1, Bc2, Bc3) in the Diagnosis of Early Breast Cancer
Background: Surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF) is an approach to biomarker discovery that combines chromatography and mass spectrometry. We aimed to consider the efficacy of Bc1, Bc2, and Bc3 serum biomarkers on early detection of breast cancer (BC) in this study
Evaluation of patients with fibrotic interstitial lung disease: Preliminary results from the Turk-UIP study
OBJECTIVE: Differential diagnosis of idiopathic pulmonary fibrosis (IPF) is important among fibrotic interstitial lung diseases (ILD). This study aimed to evaluate the rate of IPF in patients with fibrotic ILD and to determine the clinical-laboratory features of patients with and without IPF that would provide the differential diagnosis of IPF.
MATERIAL AND METHODS: The study included the patients with the usual interstitial pneumonia (UIP) pattern or possible UIP pattern on thorax high-resolution computed tomography, and/or UIP pattern, probable UIP or possible UIP pattern at lung biopsy according to the 2011 ATS/ERSARS/ALAT guidelines. Demographics and clinical and radiological data of the patients were recorded. All data recorded by researchers was evaluated by radiology and the clinical decision board.
RESULTS: A total of 336 patients (253 men, 83 women, age 65.8 +/- 9.0 years) were evaluated. Of the patients with sufficient data for diag-nosis (n=300), the diagnosis was IPF in 121 (40.3%), unclassified idiopathic interstitial pneumonia in 50 (16.7%), combined pulmonary fibrosis and emphysema (CPFE) in 40 (13.3%), and lung involvement of connective tissue disease (CTD) in 16 (5.3%). When 29 patients with definite IPF features were added to the patients with CPFE, the total number of IPF patients reached 150 (50%). Rate of male sex (p<0.001), smoking history (p<0.001), and the presence of clubbing (p=0.001) were significantly high in patients with IPE None of the women <50 years and none of the men <50 years of age without a smoking history were diagnosed with IPE Presence of at least 1 of the symptoms suggestive of CTD, erythrocyte sedimentation rate (ESR), and antinuclear antibody (FANA) positivity rates were significantly higher in the non-IPF group (p<0.001, p=0.029, p=0.009, respectively).
CONCLUSION: The rate of IPF among patients with fibrotic ILD was 50%. In the differential diagnosis of IPF, sex, smoking habits, and the presence of clubbing are important. The presence of symptoms related to CTD, ESR elevation, and EANA positivity reduce the likelihood of IPF
The Value of Serum Biomarkers (Bc1, Bc2, Bc3) in the Diagnosis of Early Breast Cancer
Background: Surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF) is an approach to biomarker discovery that combines chromatography and mass spectrometry. We aimed to consider the efficacy of Bc1, Bc2, and Bc3 serum biomarkers on early detection of breast cancer (BC) in this study.Study Design: In this prospective study, 91 patients who were admitted to our hospital between January 2007 and July 2008 were included. Serum samples from 91 women were stored at -80 °C until use. The cancer group included 27 cases of BC. The benign breast disease group included 24 women with benign breast diseases and control group 37 age-matched apparently healthy women. The data obtained for these three groups of patients was worked out for each serum biomarker (Bc1, Bc2, and Bc3) by using SELDI-TOF individually and compared with each other separately and evaluated statistically.Results: Bc2 possesses the highest individual diagnostic power. Bc2 was statistically significant in comparison between the malignant disease group, control group and benign disease group. Bc1 was statistically significant in the malignant disease group compared to control group as well as in the benign disease group compared to control group. Thus Bc1, rather than showing malignant progression, it shows tumoral progression or inflammatory process. Bc3 was found upregulated in all malignant cases; however, it was not statistically significant compared to the benign disease group or the control group.Conclusions: It has been shown that Bc2 profiles might be useful in clinical practice to improve BC diagnosis. However none of the proteomics reach reasonable AUC values for the discrimination of the BC. Additional confirmation in larger and similarly-designed prospective studies is needed to consider of the efficacy of Bc1 and Bc2 in early diagnosis of the BC.</p
Experimental Investigation of Oblique Impact Behavior of Adhesively Bonded Composite Single-Lap Joints
Determining the impact behavior of adhesive joints allows the designing of high-strength joints. Therefore, the dynamic behavior of adhesive joints has recently become a trending research topic. The study aims to examine the impact behavior and damage mechanism of the adhesively bonded composite joints, taking into account different impact angles. The mechanical behavior of adhesively bonded glass-fiber reinforced laminated composite single-lap joints under bending impact load was experimentally determined via a drop weight impact test machine. The effects of impact angle (theta = 0 degrees, 10 degrees, 20 degrees, 30 degrees), fiber angle (phi = 0 degrees, 45 degrees, 90 degrees), and overlap length (b = 25, 40 mm) on the impact behavior of the joints were investigated. These parameters were determined to affect the impact behavior of the joint and the damage characterization. The highest contact force occurred in the joints with 0 degrees fiber angle having the highest bending strength, and the lowest contact force occurred in the joints with 90 degrees fiber angle having the lowest bending strength. Due to the increase in the impact angle, the maximum contact force value in the joints decreased, while the total contact time increased. The increase in overlap length had little effect on the maximum contact force and total contact time, and the vertical displacement decreased due to the increasing bending stiffness. The unbalanced joint with 45 degrees fiber angle was forced to rotate around its axis due to in-plane unbalanced shear stress distributions induced by the bending impact load. The unbalanced shear stress distribution caused shear damage at the fiber-matrix interface and the top composite-adhesive interfaces. In joints with 0 degrees fiber angle, the impact energy was mostly met with adhesive damage, while the composite adherend was damaged as a result of increased shear stresses in the matrix region for the joints with 90 degrees fiber angle
YAPIŞTIRICI İLE BİRLEŞTİRİLMİŞ ALÜMİNYUM TEK BİNDİRME BAĞLANTILARIN DÜŞÜK HIZLI EĞİLME DARBE DAVRANIŞININ İNCELENMESİ
Low-speed bending impact behaviour of adhesively bonded dissimilar single-lap joints
This study investigates the low-speed bending impact behaviour of adhesively bonded dissimilar single-lap joints and the effects of both strength and plastic deformation capability of adherend material on adhesive failure. Dissimilar adhesive single-lap joint specimens, such as Al 2024-T3 (top adherend)-Al 5754-0 (bottom) and Al 5754-0 (top)-Al 2024-T3 (bottom), were tested at two impact energy levels (3 and 11 J) for two overlap lengths (25 and 40 mm). The progressive failure analysis of the adhesive layer was also conducted by the non-linear explicit finite element method. The adhesive layer was modelled with a 3D cohesive layer along with the upper and lower adhesive interfaces and a non-linear continuum adhesive region between two cohesive layers. The continuum adhesive region had elasto-plastic adhesive properties whilst the cohesive layers obeyed 3D cohesive rules. The experimental and predicted contact force-time, contact force-displacement diagrams, axial separation lengths of the failed adhesive region, permanent deflection of the bonded region, fracture surfaces were in good agreement. The strength and plastic deformation capability of adherend materials and impact energy levels affected the progressive adhesive failure behaviour. The proposed finite element model was successful reasonably in predicting the initiation and propagation of the adhesive failure
Finite Element Analysis of Low-Speed Oblique Impact Behavior of Adhesively Bonded Composite Single-Lap Joints
The development of a realistic numerical model that predicts the impact behavior of adhesively bonded composite joints is important for many industrial sectors such as automotive, aerospace, and marine. In this study, it was aimed to develop a numerical model that can predict the low-velocity oblique impact behavior of composite single-lap joints close to the experimental results. The validation of the proposed numerical model was carried out with the results of the previously experimentally tested joints. In explicit finite element analysis, the orthotropic material model and Hashin’s damage criterion were used in the numerical model of composite adherends. The adhesive region was divided into three different regions. The cohesive zone model (CZM) was used to determine the damage initiation and propagation in the upper and lower interface regions of adhesive. The middle region of the adhesive between the two cohesive interfaces was modeled with an elastic–plastic material model to reflect the plastic material behavior of the adhesive in the analysis. The effects of impact angle, fiber orientation, and overlap length on adhesive damage initiation and propagation were investigated in detail. There is a good agreement between the numerical and experimental results, considering the contact force-time variations and composite and adhesive damage. The impact angle and fiber angle had a significant effect on the impact behavior of the composite joints and the adhesive damage initiation and propagation. The increase in impact angle and fiber angle caused a decrease in the maximum contact force value. Adhesive damage propagation patterns varied according to the composite fiber orientation. In addition, since the shear toughness of the adhesive is higher than its tensile toughness, the amount of adhesive damage and damage propagation rate decreased as the impact angle increased
Loading-rate effect on tensile and bending strength of 3D-printed polylactic acid adhesively bonded joints
Additive manufacturing provides the production of many machine parts and components with complex geometries. The adhesive bonding technique can be alternative method for joining parts produced with additive manufacturing. This experimental study investigates the applicability of the adhesive bonding technique for PLA (polylactic acid) adherends produced with additive manufacturing and especially the effects of loading rate on the strength of 3D-printed PLA adhesive single-lap joints under tensile, three-point bending (with shear) and four-point bending (no shear effect) loadings. Both PLA and adhesive tensile test specimens exhibited a better strength but lower failure strain with increasing loading rate. PLA had better mechanical behaviour in the raster orientation than those in the layer-build direction. The strength of adhesive single-lap joints improved slightly with increasing loading rate for the tensile and three-point bending tests whilst a decrease of strength and an improvement of bending stiffness were observed for the four-point bending test. Failure initiated at the free edge of the top adherend-adhesive interface for all tests, and propagated along this interface for both bending tests whilst a sudden through-the-thickness failure of top adherend occurred for tensile load after a small interfacial damage propagation. The failure propagation appeared in a wavy form for the three-point bending test whilst it was along the top adherend-adhesive interface for the four-point bending test. Digital Image Correlation (DIC) method for tensile tests showed that the peeling and shear strains were more critical and concentrated around both free edges of adherend-adhesive interfaces; thus, at the right free edge of the top adherend-adhesive interface and at the left free edge of the bottom adherend-adhesive interface
Low-Speed Oblique Impact Response of Adhesively Bonded Dissimilar Single-Lap Joints
© 2022 American Society of Civil Engineers.Adhesively bonded joints are widely preferred for joining similar and dissimilar materials due to the mechanical advantages they provide. As the demand for the adhesively bonded method increases, it is necessary to determine the behavior of joints under impact loads for joint design. The aim of this study was to investigate the low-speed oblique impact behavior of dissimilar single-lap joints and the effect of plastic deformation ability and strength of the adherends [(Top) Al 2024-T3-(Bottom) Al 5754-0, (Top) Al 5754-0-(Bottom) Al 2024-T3], overlap lengths (25, 40 mm), and impact energy (3, 11 J) on adhesive damage. The behavior of the joints determined by the numerical model under low-speed oblique impact was compared with experimental results. Considering the contact force-time, contact force-displacement, and adhesive damage, the numerical model was reasonably compatible with the experimental results. The damage initiation and propagation in the adhesive layer were determined by three-dimensional explicit finite-element analysis. In order to obtain suitability for the damage mechanism by observing the experimental bonding damage surfaces, the adhesive region was divided into three zones, the upper and lower adhesive interfaces and a middle adhesive layer between them. The different strength and plastic deformation ability of the adherends had a significant effect on the adhesive damage initiation and propagation. In the case of high strength and low deformation ability of the adherend material (Al 2024-T3) contacting with the impactor, a reduction of the adhesive damage occurred due to the deformation of the adherend material (bottom adherend) with low strength and high deformation capability. The oblique impact load and the different mechanical properties of the adherends greatly affected the adhesive damage initiation and propagation of single-lap joints