Predictors of mortality in patients with prosthetic valve infective endocarditis: A nation-wide multicenter study

Background: Our aim was to investigate the clinical and prognostic features of the patients with prosthetic valve endocarditis (PVE) in a multicenter nation-wide study.Methods: The present nation-wide study consisted of 75 consecutive patients with PVE treatedat 13 major hospitals in Turkey from 2005 to 2012.Results: The patients who died during follow-up were significantly older than the survivors and had higher C-reactive protein (CRP), creatinine, poor NYHA functional class and large vegetations. High creatinine level (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.14–6.13), poor functional status (OR 24.5; 95% CI 3.1–196.5) and high CRP (OR 1.02; 95% CI1.00–1.03) measured on admission were independent risk associates for in-hospital mortality.Conclusions: High creatinine level, poor functional status and high CRP measured on admission were independent risk associates for in-hospital mortality, whereas a NYHA class ofIII/IV and high CRP reflected independent risk for stroke/mortality end point

Enhancing the sensitivity of nanopipette biosensors for protein analysis

Abstract Background This paper compares experimental findings and simulation outcomes of single and multiple protein models moving through a nanopipette biosensor. It provides insights into the factors influencing the process and explores their relevance to proteomics. Methods Nanopipette biosensors were produced by pulling borosilicate glass tubes and treating them with an electron beam. A scanning electron microscope was used to characterize the nanopipettes. The study measured and modeled ionic currents for the elastase‐specific inhibitor protein. Simulation models were developed using the finite element method and Poisson–Boltzmann formalism, considering different protein configurations and translocation scenarios. Results The results showed that the pore current of a nanopipette decreases as the protein approaches the nanopipette. The minimum pore current occurs at the widest part of the protein, and the current increases as the protein progresses through the nanopipette. For multiple protein translocations, the pore current decreases between the widest parts of the first and second proteins, and the lowest current is observed at the broadest part of the second protein. After the third protein, the pore current remains constant. It is also found that the fractional blockade difference, translocation speed, fluctuation in pore current, and dwell time are all affected by the number of proteins translocating through the nanopipette. The fractional blockade difference, the decrease in pore current caused by the protein, increases with the number of proteins while the translocation speed decreases. The fluctuation in pore current and dwell time is also longer for three‐protein translocations than for single‐protein translocations. Conclusion This study offers valuable insights into biomolecule transport through nanopipettes, enhances our understanding of protein dynamics in restricted environments, and significantly contributes to single‐protein sequencing studies, drug screening, and proteomics

EXPERIMENTAL ANALYSIS OF THE EFFECT OF MECHANICAL PROPERTIES AND MICROSTRUCTURE ON TOOL VIBRATION AND SURFACE QUALITY IN DRY TURNING OF HARDENED AISI 4340 STEELS

AISI 4340 (34CrNiMo6) steel is a difficult to machine steel material because of its high hardness and tendency to get strain hardened. These steels are mostly used in manufacturing of the axle parts, drive coupling, and rotating shafts due to their high mechanical properties. In this experimental study, the effects of mechanical properties and microstructure on tool vibration and surface quality in dry turning of hardened AISI 4340 steels were investigated. Test samples were classified as Raw Material (RM), Conventional Heat Treatment (CHT) and Tempering process (T). The experiments were carried out under dry cutting conditions by different cutting parameters on the CNC turning lathe. Three axes vibration amplitude values (along the x-, y- and z-directions) were measured using accelerometers as online and surface roughness (Ra) values were measured with the surface roughness device. Tool vibrations and Ra values were found to be lower in T sample compared to the RM and CHT samples. When the samples were analyzed in terms of microstructure and mechanical properties, it was seen that the tensile strength increased as the hardness values increased. After the tempering process at 200(circle)C, pearlite and bainitic structures emerged along with the martensite structure. The surface quality that can be obtained on a cylindrical grinding lathe, has been reached with the dry turning process. Significant gains have been achieved in terms of cost and time.Scientific Research Projects Coordination (BAP) of Duzce UniversityDuzce University [BAP-2019.22.01.911]The authors would like to acknowledge the support of Scientific Research Projects Coordination (BAP) of Duzce University for the project entitled BAP-2019.22.01.911.WOS:0006628054000022-s2.0-8510454412

Analysis of tool vibration and surface roughness during turning process of tempered steel samples using Taguchi method

This study analyzed the tool vibration (Vib) and surface roughness (Ra) during turning of AISI 4340 (34CrNiMo6) tempered steel samples using Taguchi Method. In this context, Taguchi design L-18 (2(1) x 3(2)) was used to analyze the experimental results. The vibration amplitude values from cutting tools were recorded for different machining parameters, control factors; two different sample hardness (46 and 53 HRc), three different cutting speeds (180, 220, 260 m.min(-1)), and feed rates (0.08, 0.14, 0.20 mm.rev(-1)) were selected. The machining parameters giving optimum Vib and Ra values were determined. Regression analysis is applied to predict values of Vib and Ra. Analysis of variance was used to determine the effects of machining parameters on the Vib and Ra values. The most important machining parameters were found to be the feed rate, sample hardness, and cutting speed for Vib and Ra, respectively. The lowest Vib and Ra values were obtained in 46 HRc sample as 0.0022 gRMS and 0.255 mu m, respectively. The surface quality can be improved by reducing the sources of vibration by using appropriate machining parameters. As a result, there is a significant relationship between Ra and Vib. The lower Ra values were found during turning process of tempered steel samples according to the literature studies. It is suggested that the process can be preferred as an alternative process to grinding process due to lower cost and machining time. In application of the turning of experiment samples by ceramic cutting tool, a substantial technological and economical benefit has been observed.Scientific Research Projects Coordination (BAP) of the University of Duzce [BAP-2019.22.01.911]The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors would like to acknowledge the support of Scientific Research Projects Coordination (BAP) of the University of Duzce for the project entitled BAP-2019.22.01.911.WOS:0006359952000012-s2.0-8510281346

Dynamic Response of Multi-bay Frames Subjected to Successive Moving Forces

This paper investigates the dynamic responses of multi-bay frames with identical bay lengths subjected to a transverse single moving load and successive moving loads with a constant interval at a constant speed. The effects of the bay length and the speed of the moving load on the response of the multi-bay frame subjected to a single point load are investigated numerically by the finite element method. A computer code is developed by using MATLAB to perform the finite element analysis. The Newmark method is employed to solve for the dynamic responses of the multi-bay frame. With this, the dynamic response of the frame subjected to successive moving loads with a constant interval is investigated. Also, the resonance and cancellation speeds are determined by using the 3D relationship of speed parameter-force span length to beam length ratio-dynamic magnification factor and the associated contour lines. The maximum impact factor of a 1-bay frame and multi-bay frames under single moving load are determined at the specific speed parameters. Those values are independent of elastic modulus, area moment of inertia, beam/column lengths of the frame and also the number of bays forming the frame. It is also found that the first resonance response in the vertical direction of the frame is related to the second mode of vibration

A Tuberculosis pleuresia mimicking cardiomegaly

WOS: 000251886600242

Rigorous Bicycling Does Not Increase Serum Levels of Total and Free Prostate-specific Antigen (PSA), the Free/Total PSA Ratio, Gonadotropin Levels, or Uroflowmetric Parameters

OBJECTIVES To determine whether cycling has an effect on serum PSA, gonadotropins, and uroflowmetric parameters

Brucellosis in Childhood

Objective: Brucellosis is still an important infectious disease, being widespread as endemic and sporadic cases in Turkey. The aim of this study was to evaluate clinical and laboratory findings, treatment modalities and final outcomes of brucellosis in children

Spontaneous cholesterol embolism confused with peripheral arterial disease

WOS: 000254244200034PubMed ID: 18065361