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关键词： Diesel engines  

摘要： The roller-floating bush pin is a major component in the fuel supply mechanism of a diesel engine, and its tribological performance seriously affects the reliability of the equipment. In this study, a transient thermoelastic hydrodynamic lubrication analysis model of the double-layer oil film on the roller-floating bush pin is established, which is coupled with the dynamic and kinematic analysis model of the cam-roller. The transient dynamic characteristics, such as time-varying speeds and loads of the roller during the operation of the cam, were considered. Also, the elastic deformation and the thermal effect were considered in the lubrication model. The relevant experimental platform for this double-layer oil film lubrication structure was built, and the simulation model was verified through experiments. The influence of the operating conditions, including cam speed and plunger fuel pressure, on the lubrication performance of the structure is explored, and besides, the influence of the structural parameters, including length-diameter ratios and clearance ratios, is also analyzed. It shows the lubrication condition of the inner oil film is worse compared with the outer oil film. As the explored factors change, the pressure of the inner oil film is more affected than that of the outer oil film. This work could provide useful guidance in designing the roller-floating bush pin in the fuel supply mechanism.

关键词： clozapine   CAM   clozapine associated myocarditis   myocarditis   rechallenge   treatment resistant psychosis   schizophrenia   clozapine induced myocarditis  

摘要： Introduction and Objectives. Clozapine is the antipsychotic medication with the greatest efficacy in treatment-resistant schizophrenia (TRS). Unfortunately, clozapine is ceased in approximately 0.2% to 8.5% of people due to concerns about clozapine-associated myocarditis (CAM). The opportunity for clozapine rechallenge is important for people with TRS and CAM, due to limited alternative treatments. However, there is a lack of consensus regarding the optimal process, monitoring, and dose titration to achieve successful clozapine rechallenge. The study aimed to review the process, monitoring, and dose titration within cases of clozapine rechallenge after CAM, to identify features associated with successful rechallenge. Methods. A systematic review of clozapine rechallenge cases following CAM was conducted. PubMed, EMBASE, Cinahl, and PsycINFO were searched for cases. Reference lists of retrieved articles and field experts were consulted to identify additional studies. Results. Forty-five cases were identified that described clozapine rechallenge, 31 of which were successful. Successful rechallenge cases generally used a slower dose titration regime with more frequent monitoring than standard clozapine initiation protocols;however, this data was not always completely recorded within cases. Six cases referred to published rechallenge protocols to guide their rechallenge. Conclusions. The process, monitoring, and dose titration of clozapine rechallenge are inconsistently reported in the literature. Despite this, 69% of case reports detailed a successful rechallenge post CAM;noting limitations associated with reliance on case data. Ensuring published clozapine rechallenge cases report standardised data, including titration speed and monitoring frequencies, is required to guide the development and validation of guidelines for clozapine rechallenge.

关键词： Acute coronary syndrome   Antiplatelet therapy   Aspirin   Hemorrhage   Odds ratio   Percutaneous coronary intervention   Randomized trials   Stable coronary artery disease   Stent implantation   Thrombosis  

摘要： AbstractSource CitationBajraktari G, Bytyçi I, Abdyli G, et al. One-month dual antiplatelet therapy reduces major bleeding compared with longer-term treatment without excess stent thrombosis: a systematic review and meta-analysis of randomized clinical trials. Am J Cardiol. 2024;227:91-97. https://***/39029722/AbstractClinical Impact RatingsGIM/FP/GP: Cardiology: Hematology:

关键词： CAD/CAM   Vickers hardness   Translucency parameter   Resin composite   Light curing  

摘要： The study assessed the depth of cure (DOC) of different resin composites light-cured through different types of CAD/CAM materials of variable thickness. Three CAD/CAM materials (multilayer zirconia, lithium disilicate glass ceramic, composite) of three thicknesses (2-, 3-, and 4-mm) were prepared and their translucency parameter (TP) were measured. A light-curable and a dual-curable resin cement (Variolink Esthetic LC and DC) and a bulk-fill resin composite with a higher Ivocerin concentration (Tetric PowerFill) were used to mimic luting agents. DOC was assessed via Vickers microhardness testing. Increased thickness of CAD/CAM specimen was associated with decreased DOC. The chemical composition of the resin composites affected their curing performance depending on the light curing mode. Tetric PowerFill presented the greater DOC among the other resin composites. Receiver operating characteristic models of curing status appeared to provide better insight in predicting the DOC of luting agent according to TP than linear regression.

关键词： obesity   CTCA   CAD   proximal coronary segment  

摘要： Computed tomography coronary angiography (CTCA) is under-utilised in detecting coronary artery disease (CAD) in obese patients due to concerns about non-evaluable testing. We hypothesise that these concerns are predominantly related to smaller and branch coronary vessels, and CTCA remains adequate for proximal segment stenosis interpretation, which has significant clinical implications. This retrospective cohort study, on consecutive patients referred for CTCA for suspected CAD, grouped patients by body mass index. A 4-point Likert scale assessed image quality, with any poorly visualised segment at the per-patient level resulting in the CTCA being subsequently analysed for proximal coronary artery segment evaluability. Of the 703 patients, 93.5% of the studies were fully evaluable. Patients with a BMI >= 40, diabetic patients, and patients with an elevated acquisition heart rate were associated with suboptimal studies. Of the 46 suboptimal studies, 163/182 (90%) of proximal segments were fully evaluable. Non-evaluable segments were derived from seven patients (one with a BMI >= 40). Reasons for proximal segment non-evaluability were predominantly due to calcific blooming (12/19 segments). While CTCA may be less reliable for distal and side-branch artery evaluation in obese patients, it remains highly evaluable for stenosis severity of the proximal main coronary segments, which carries prognostic significance. It may therefore be considered a suitable non-invasive anatomic test for patients, regardless of BMI.

关键词： crassulacean acid metabolism   RNA-Seq   gene regulation   heat shock proteins  

摘要： Temperature stress is one of the major limiting environmental factors that negatively impact global crop yields. Kalancho & euml;fedtschenkoi is an obligate crassulacean acid metabolism (CAM) plant species, exhibiting much higher water-use efficiency and tolerance to drought and heat stresses than C3 or C4 plant species. Previous studies on gene expression responses to low- or high-temperature stress have been focused on C3 and C4 plants. There is a lack of information about the regulation of gene expression by low and high temperatures in CAM plants. To address this knowledge gap, we performed transcriptome sequencing (RNA-Seq) of leaf and root tissues of K. fedtschenkoi under cold (8 degrees C), normal (25 degrees C), and heat (37 degrees C) conditions at dawn (i.e., 2 h before the light period) and dusk (i.e., 2 h before the dark period). Our analysis revealed differentially expressed genes (DEGs) under cold or heat treatment in comparison to normal conditions in leaf or root tissue at each of the two time points. In particular, DEGs exhibiting either the same or opposite direction of expression change (either up-regulated or down-regulated) under cold and heat treatments were identified. In addition, we analyzed gene co-expression modules regulated by cold or heat treatment, and we performed in-depth analyses of expression regulation by temperature stresses for selected gene categories, including CAM-related genes, genes encoding heat shock factors and heat shock proteins, circadian rhythm genes, and stomatal movement genes. Our study highlights both the common and distinct molecular strategies employed by CAM and C3/C4 plants in adapting to extreme temperatures, providing new insights into the molecular mechanisms underlying temperature stress responses in CAM species.

关键词： CAD/CAM   dental materials   prophylaxis paste   fatigue   prophylactic paste   surface roughness  

摘要： The surface of dental materials is exposed to various prophylaxis protocols during routine dental care. However, the impact of these protocols on the functional properties of the material's surface remains unclear. This study investigates the influence of different dental prophylaxis protocols on the surface properties and their effect on the mechanical performance of CAD-CAM restorative materials. Discs (& Oslash;= 15 mm, thickness = 1.2 mm) were fabricated from resin composite (RC, Tetric CAD), leucite-reinforced (LEU, IPS Empress CAD), lithium disilicate (LD, IPS *** CAD), and zirconia ceramics (ZIR, IPS *** ZirCAD MT). The materials were subjected to six prophylactic treatments: untreated (CTRL), prophylactic paste fine (PPF), prophylactic paste coarse (PPC), pumice stone (PS), air abrasion with sodium bicarbonate jet (BJ), and ultrasonic scaling (US). Biaxial flexural fatigue tests, along with fractographic, roughness, and topographic analyses, were conducted. No significant changes in fatigue strength were observed for RC, LD, and ZIR under any prophylaxis protocols. However, LEU subjected to BJ treatment exhibited significantly reduced fatigue strength (p = 0.004), with a 22% strength reduction compared to the monotonic test and substantial surface alterations. Surface roughness analyses revealed increased roughness for RC treated with PPF, PPC, and PS compared to CTRL (p < 0.05), while LD exhibited decreased roughness following PPF, PS, and US treatments (p < 0.05). In ZIR, only the BJ protocol increased roughness (p = 0.001). In conclusion, dental prophylaxis protocols do not significantly affect the mechanical strength of RC, LD, and ZIR materials, thus allowing any protocol to be used for these materials. However, for LEU ceramics, the BJ protocol should be avoided due to its effect of reducing fatigue strength and damaging the surface.

关键词： Lunar rover   Microscope   Regolith  

摘要： The microscope imager CAM-M was developed for the Emirates Lunar Mission (ELM) program. This camera is part of the Rashid-1 lunar rover scientific instrument package. It is equipped with a three color RGB CMOS detector, delivering a spatial sampling varying between 20 and 27 mu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mu $\end{document}m per pixel across its field of view. The viewing geometry of this camera was chosen such that its field of view on the ground is slightly ahead of the rover, thereby showing the undisturbed lunar surface. Its multi-purpose illumination system allows to acquire images in shadowed areas but as well to support the rover drive operations. Since CAM-M does not contain any moving parts, its imaging performance depends on suitable positioning of the rover with respect to the field of view. Hence, CAM-M should be seen as a scouting instrument which acquires images at every possible stop along its traverse. This paper provides a summarizing description of the instruments design, its operation concepts, and to illustrate this camera's scientific capabilities by means of data collected during on-ground testing. Due to the unsuccessful landing attempt of the lunar lander which was carrying the Rashid-1 rover to the Moon, CAM-M was unable to collect any data on the lunar surface.

关键词： provisional   crown   CAD/CAM   bracket   bonding  

摘要： The aim of the study is to assess the impact of mechanical surface treatments on the shear bond strength (SBS) of orthodontic brackets bonded to three-dimensional (3D) printed and milled CAD/CAM provisional materials. Sixty cylindrical samples were fabricated for each provisional material. Samples were treated with one of the following surface treatments: aluminum oxide airborne particle abrasion, diamond bur rotary instrument roughening, and phosphoric acid etching (control). Stainless steel brackets were bonded to the samples, and then SBS was tested using a universal testing machine. SEM and digital microscopy were utilized to examine the bonding interface and the failure modes. Two-way ANOVA, one-way ANOVA, Tukey's HSD, and independent sample t-tests were used for statistical analysis. Results revealed significant differences in SBS between 3D printed and milled samples and significant differences in SBS among most surface treatments, with rotary instrument roughening resulting in the highest values for 3D printed, while airborne particle abrasion leading for milled samples. Digital microscopy indicated that more adhesive remained on 3D-printed samples. SEM analysis revealed varying surface roughness across treatments. Based on the findings of this study, it can be concluded that different surface treatments improve the bonding of orthodontic brackets to provisional crowns.

关键词： Friction   surface engineering   energy efficiency   micro-surface-texturing   cam   tappet   valve train   temperature   RPM   Thermo-Elastohydrodynamically Lubricated (TEHL)  

摘要： Reduced wear and friction are directly related to longer component service lives and increased energy efficiency. The mechanisms used to achieve this goal in mechanical systems include the study of lubricant chemistry, surface coating, and surface modification. Significant research has been conducted on friction reduction of valve trains of internal combustion engines using surface modifications such as coatings and surface texturing. Here, an experimental approach has been adopted to investigate the effect of micro surface texturing on Thermo-Elastohydrodynamically Lubricated cam/tappet contact in a direct-acting valve train. A commercial vehicle valve train has been instrumented to study the effect of varying surface texture area density on friction under realistic engine operating conditions. Fiber laser surface texturing has been used to microtexture three samples of tappet shims with texture densities of 5%, 8%, and 10%. The tests have been run at four engine speeds-300, 500, 700, and 900 RPM-and three temperatures-30 degrees C, 60 degrees C, and 90 degrees C. The experimental results show a significant friction reduction of up to 18.33% for textured shims at the temperature of 90 degrees C. The friction reduction performance of the 8% textured shim has been optimum for all RPMs at the higher temperatures.