Search

OBJECTIVES/GOALS: The goal of the study is to provide insights into the use of machine learning methods as a means to predict heterogeneity of treatment effect (HTE) in participants of randomized clinical trials. METHODS/STUDY POPULATION: Using data from 2,441 participants enrolled in the ASPirin in Reducing Events in the Elderly (ASPREE) randomized controlled trial of daily low-dose aspirin vs placebo in the United States, we developed multivariable risk prediction models for the composite outcome of dementia, disability, or death. We used two machine learning techniques, decision trees and random forests, to develop novel non-parametric outcomes classifiers and generate risk-based subgroups. The comparator method was an extant semi-parametric proportional hazards predictive risk model. We then assessed HTE by examining the 5-year absolute risk reduction (ARR) of aspirin vs placebo in each risk subgroup. RESULTS/ANTICIPATED RESULTS: In the random forest classifier, the ARR at 5 years in the highest risk quintile was 13.7% (95% CI 3.1% to 24.4%). For the semi-parametric proportional hazards model, the ARR in the highest risk quintile was 15.1% (95% CI 4.0% to 26.3%). These results were comparable and provide evidence of the viability of internally developed parsimonious non-parametric machine learning models for HTE analysis. The decision tree model results (5-year ARR = 17.0%, 95% CI= -5.4% to 39.4% in the highest risk subgroup) exhibited more uncertainty in the results. DISCUSSION/SIGNIFICANCE: None of the models detected significant HTE on the relative scale; there was substantial HTE on the absolute scale in three of the models. Treatment benefit on the absolute scale may be regarded as bearing greater clinical importance and may be present even in the absence of benefit on the relative scale.

A percutaneous cholecystostomy tube (PCT) is the conventionally favored nonoperative intervention for treating acute cholecystitis. However, PCT is beset by high adverse event rates, need for scheduled reintervention, and inadvertent dislodgement, as well as patient dissatisfaction with a percutaneous drain. Recent advances in endoscopic therapy involve the implementation of endoscopic transpapillary drainage (ETP-GBD) and endoscopic ultrasound-guided gallbladder drainage (EUS-GBD), which are increasingly preferred over PCT due to their favorable technical and clinical success combined with lower complication rates. In this article, we provide a comprehensive review of the literature on EUS-GBD and ETP-GBD, delineating instances when clinicians should opt for endoscopic management and highlighting potential risks associated with each approach.

Background: There is an incomplete understanding of the predictors of morbidity and mortality in patients with severe tricuspid regurgitation (TR). This study sought to identify key risk factors for all-cause mortality and heart failure (HF) hospitalization among patients with severe TR. Methods: Patients with severe TR were identified from 2 centers, Oregon Health & Science University and Abrazo Health, from January 01, 2016 to December 31, 2018. Patients with any concomitant severe valvular diseases or prior valvular intervention were excluded. Multivariable regression was utilized to identify demographic, clinical, and echocardiographic variables independently associated with all-cause mortality or HF hospitalization. Results: 435 patients with severe TR were followed for a median of 2.8 years. The mean age of the population was 66.9 ± 18.5 years and 58% were female. All-cause mortality was identified in 20.5% of the population. Of the cohort, 35.4% of patients were hospitalized for HF. Isolated tricuspid valve intervention was performed in 2.5% of patients. Independent predictors of all-cause mortality included history of solid tumor (odds ratio [OR] 6.6, 95% confidence interval [CI] 2.1-19.1, p = 0.001), history of peripheral artery disease (OR 3.5, 95% CI 1.2-9.4, p = 0.013), and elevated international normalized ratio in the absence of anticoagulation (OR 1.9, 95% CI 1.2-3.2, p = 0.008). Predictors of HF hospitalization included history of diabetes mellitus (OR 2.2, 95% CI 1.1-4.0, p = 0.014) and history of reduced left ventricular ejection fraction (OR 5.7, 95% CI 2.9-11.7, p < 0.0001). Conclusions: Severe untreated TR is associated with high mortality and frequent HF hospitalizations. Understanding predictors of these outcomes is important to identify patients who may benefit from early tricuspid valve intervention to help improve outcomes in this patient population.

Many grease-lubricated machines operate in wet environments, and are vulnerable to contamination because of water exposure. Reports suggest that even the presence of 1% water in grease reduces the life of a bearing by 90%. Nevertheless, only a few qualitative tests and standards are available to characterize the water resistance properties of greases. In this paper, we propose a standard for evaluating the water resistance properties of greases by studying their hydrophobic and hydrophilic nature via a custom-designed apparatus for measuring the grease contact angle. In this approach, a water droplet is dispensed onto the surface of the grease and the contact angle of the droplet is studied. For this purpose, an apparatus was designed, built, and tested with twelve different greases. To validate the efficacy of the test method and setup, tests were performed at two different locations by independent operators. From the obtained contact angle values, the authors propose categorizing a grease’s water-resistance properties into five different grades that can be set as guidelines for the industrial user when selecting a grease for machinery operation in a wet environment. The classification of the water-repellent properties of greases, using the proposed standard is compared with existing ASTM standards used for evaluation of grease properties in the presence of water.

Oil and Gas Pipeline (OGP) projects face a wide range of safety and security Risk Factors (RFs) globally, particularly in the oil and gas producing countries having insecure environment and poor safety records. Inadequate information about the causes of pipeline failures and poor knowledge about the safety and the security of the OGP hinder efforts of mitigating such risks. This paper, therefore, aims to develop a risk management system that is based on a holistic approach of identifying, analysing and ranking the associated RFs, and evaluating the possible Risk Mitigation Methods (RMMs), which are the first steps of this approach. A qualitative document analysis was adopted to design a semi-structured industry-wide questionnaire, which was conducted to collect stakeholders’ perceptions about existing RFs and RMMs for the OGP projects in Iraq. From the survey results, probability and severity levels of the RFs were used as inputs for a computer-based risk analysis model. The model used the fuzzy theory to judge the probability and consequence levels of the RFs and rank them with regards to their degree of impact in the projects. The results revealed that terrorism, official corruption and insecure areas are the most critical risks. Similarly, the RMMs were evaluated based on their degree of efficacy to mitigate the risk in OGP projects. This paper presents a prototype of the risk management system that will be further developed in the next stage of the study.

Large-scale applications of nanotechnology have been extensively studied within the last decade. By exploiting certain advantageous properties of nanomaterials, multifunctional products can be manufactured that can contribute to the improvement of everyday life. In recent years, one such material has been nanocellulose. Nanocellulose (NC) is a naturally occurring nanomaterial and a high-performance additive extracted from plant fibers. This sustainable material is characterized by a unique combination of exceptional properties, including high tensile strength, biocompatibility, and electrical conductivity. In recent studies, these unique properties of nanocellulose have been analyzed and applied to processes related to membrane technology. This article provides a review of recent synthesis methods and characterization of nanocellulose-based membranes, followed by a study of their applications on a larger scale. The article reviews successful case studies of the incorporation of nanocellulose in different types of membrane materials, as well as their utilization in water purification, desalination, gas separations/gas barriers, and antimicrobial applications, in an effort to provide an enhanced comprehension of their capabilities in commercial products.

ABSTRACT The most pressing challenge for the development of anti-capsular antibodies is maximizing coverage against the heterogenous capsular polysaccharide (CPS) of carbapenem-resistant Klebsiella pneumoniae (CR-Kp). So far, only CR-Kp with wzi154 CPS has been successfully targeted by antibodies. Here, we present murine antibody 24D11, which was developed by vaccinating mice with purified wzi50-type CPS. Cross-reactivity and protective efficacy of MAb 24D11 were confirmed against CR-Kp that express the 3 most prevalent CPS types (wzi29, wzi154, wzi50) using both in vitro and in vivo infection models. 24D11 induced complement-mediated and independent opsonophagocytosis in macrophages as well as killing of all CR-Kp strains in whole blood cells derived from healthy donors. In a murine intratracheal infection model, 24D11 reduced lung burden and dissemination of CR-Kp strains when administered 4 h pre- or postinfection. The protective efficacy of 24D11 remained effective in neutropenic mice. This is the first antibody which exhibits cross-protective efficacy against clade 1 and 2 ST258 CR-Kp strains. It overcomes a major barrier to successfully target wzi29, a major CPS expressed by ST258 CR-Kp. The finding that 24D11 also exhibits potent protective efficacy against wzi154 CR-Kp strains highlights its high potential as a lead agent for the development of broadly active immunotherapy. IMPORTANCE Here, we present in vitro and in vivo data for the wzi50 CPS-specific monoclonal antibody MAb 24D11, demonstrating its cross-protective efficacy against three prominent win types (wzi29, wzi154, and wzi50) of the carbapenem-resistant clonal group CG258. In a murine pulmonary infection model, MAb 24D11 reduced bacterial lung burden and dissemination to other organs even if administered 4 h postinfection. Its protective efficacy was also observed in neutropenic mice, which highlights its potential value in clinical settings where oncology patients with CG258 infections may also be neutropenic.

Background and study aims The COVID-19 pandemic has had a profound impact on gastroenterology training programs. We aimed to objectively evaluate procedural training volume and impact of COVID-19 on gastroenterology fellowship programs in the United States. Methods This was a retrospective, multicenter study. Procedure volume data on upper and lower endoscopies performed by gastroenterology fellows was abstracted directly from the electronic medical record. The study period was stratified into 2 time periods: Study Period 1, SP1 (03/15/2020 to 06/30/2020) and Study Period 2, SP2 (07/01/2020 to 12/15/2020). Procedure volumes during SP1 and SP2 were compared to Historic Period 1 (HP1) (03/15/2019 to 06/30/2019) and Historic Period 2 (HP2) (07/01/2019 to 12/15/2019) as historical reference. Results Data from 23 gastroenterology fellowship programs (total procedures = 127,958) with a median of 284 fellows (range 273–289; representing 17.8 % of all trainees in the United States) were collected. Compared to HP1, fellows performed 53.6 % less procedures in SP1 (total volume: 28,808 vs 13,378; mean 105.52 ± 71.94 vs 47.61 ± 41.43 per fellow; P

Additive manufacturing (AM) has recently become an increasingly popular form of production due to its advantages over traditional manufacturing methods, such as accessibility, the potential to produce parts with complex geometry, and reduced waste. For the widespread industry adoption of AM components, metal AM has the most potential. The most popular methods of metal AM are powder-based manufacturing techniques. Due to the layer-by-layer nature of AM, the mechanical and tribological properties of an additive manufactured part differs from those of traditionally manufactured components. For the technology to develop and grow further, the tribological properties of AM components must be fully explored and characterized. The choice of material, surface textures, and post-processing methods are shown to have significant impact on friction and wear. Therefore, this paper focuses on reviewing the existing literature with an emphasis on the development of advanced materials for AM applications as well as the optimization of the resulting surface quality via post-processing and presents areas of interest for further examination in this prospective technology.

Gaining grounds as a potential heat transfer fluid due to its superior thermal and tribological properties, Nanofluid Minimum Quantity Lubrication (NMQL) has been classified as an environmentally friendly technique and has already been successfully applied in several machining processes. This paper presents a review of the role of NMQL for different machining processes. The mechanisms of the MQL technique are thoroughly explained for achieving optimal performance based on parameters like nozzle feed position, angle of elevation, distance from the nozzle tip to cutting zone, flow rate, and air pressure. NMQL is shown to enhance cooling performance and lubrication, as well as the tribological properties of the fluid and cutting performance. With government legislative and public opinion pushing manufacturing companies towards sustainable production techniques and practices, the implementation of MQL-nanofluid can slowly prevent the adverse effects that conventional cutting fluids contribute.

Cancer is the second leading cause of death, and incidences are increasing globally. Simply defined, cancer is the uncontrolled proliferation of a cell, and depending on the tissue of origin, the cancer etiology, biology, progression, prognosis, and treatment will differ. Carcinogenesis and its progression are associated with genetic factors that can either be inherited and/or acquired and are classified as an oncogene or tumor suppressor. Many of these genetic factors converge on common signaling pathway(s), such as the MAPK and PI3K/AKT pathways. In this review, we will focus on the metabotropic glutamate receptor (mGluR) family, an upstream protein that transmits extracellular signals into the cell and has been shown to regulate many aspects of tumor development and progression. We explore the involvement of members of this receptor family in various cancers that include breast cancer, colorectal cancer, glioma, kidney cancer, melanoma, oral cancer, osteosarcoma, pancreatic cancer, prostate cancer, and T-cell cancers. Intriguingly, depending on the member, mGluRs can either be classified as oncogenes or tumor suppressors, although in general most act as an oncogene. The extensive work done to elucidate the role of mGluRs in various cancers suggests that it might be a viable strategy to therapeutically target glutamatergic signaling.

Introduction: Increased faculty and resident responsibilities have ledto the decreased time available for teaching clinical skills to medicalstudents. Numerous advances in education and simulation haveattempted to obviate this problem; however, documented success islacking. Our objective was to describe a novel fresh cadaver-based,student-driven procedural skills lab and to compare the educationaleffectiveness of student instructors to the senior instructor (SI).Methods: This was a prospective study performed at an academicmedical center. A pilot program, “Students Teaching Students,” wasintroduced where four trained first-year medical students (TMS)instructed 41 other untrained first-year medical students in technicalprocedures. This study compared the teaching evaluations of theSI with the TMS teaching equivalent procedures. Paired t-test wasused to determine statistically significant changes in proceduralconfidence between pre- and post-training. Utilizing a post-trainingquestionnaire, average post-training confidence improvement valuesand objective post-training test scores of the participants werecompared between TMS and SI, using a 2 sample t-test. Statisticalsignificance was considered as a p

Future progress in hybrid and battery vehicles heavily relies on the optimization of involved battery components and lubricants. Attention must specifically be given to the material composition and surface coatings of the electrodes as well as the electrolyte used to maximize energy output, while also ensuring safety. Additionally, prioritizing the effective utilization of specific lubricants for electric motors and various tribological contacts, such as wheel bearings and the steering system, is the prospective goal of lubrication research. The energy output of the most promising battery, the Li-ion battery (LIB), must result in driving ranges, which can compete with the 600 km driving range of combustion engine (ICE) vehicles. Consequently, ongoing research activities in cell chemistry, electrode surface engineering, electrolyte engineering, and engine lubrication offer the greatest opportunity in achieving these goals.

Introduction: The impact of radiation prescription dose on postoperative complications during standard of care trimodality therapy for operable stage II-III esophageal and gastroesophageal junction cancers has not been established.Methods: We retrospectively reviewed 82 patients with esophageal or gastroesophageal junction cancers treated between 2004 and 2016 with neoadjuvant chemoradiation followed by resection at a single institution. Post-operative complications within 30 days were reviewed and scored using the Comprehensive Complication Index (CCI). Results were compared between patients treated with

Lithium-ion batteries have enabled electric vehicles to achieve a foothold in the automobile market. Due to an increasing environmental consciousness, electric vehicles are expected to take a larger portion of the market, with the ultimate goal of supplanting traditional vehicles. However, the involved costs, sustainability, and technical limitations of lithium-ion batteries do create substantial obstacles to this goal. Therefore, this article aims at presenting magnesium-ion batteries as a potential replacement for lithium-ion batteries. Though still under development, magnesium-ion batteries show promise in achieving similar volumetric and specific capacities to lithium-ion batteries. Additionally, magnesium is substantially more abundant than lithium, allowing for the batteries to be cheaper and more sustainable. Numerous technical challenges related to cathode and electrolyte selection are yet to be solved for magnesium-ion batteries. This paper discusses the current state-of-the-art of magnesium-ion batteries with a particular emphasis on the material selection. Although, current research indicates that sulfur-based cathodes coupled with a (HMDS) 2 Mg-based electrolyte shows substantial promise, other options could allow for a better performing battery. This paper addresses the challenges (materials and costs) and benefits associated with developing these batteries. When overcoming these challenges, magnesium-ion batteries are posed to be a groundbreaking technology potentially revolutionizing the vehicle industry.

Melanoma, a cancer of the skin, arises from transformed melanocytes. Melanoma has the highest mutational burden of any cancer partially attributed to UV induced DNA damage. Localized melanoma is “curable” by surgical resection and is followed by radiation therapy to eliminate any remaining cancer cells. Targeted therapies against components of the MAPK signaling cascade and immunotherapies which block immune checkpoints have shown remarkable clinical responses, however with the onset of resistance in most patients, and, disease relapse, these patients eventually become refractory to treatments. Although great advances have been made in our understanding of the metastatic process in cancers including melanoma, therapy failure suggests that much remains to be learned and understood about the multi-step process of tumor metastasis. In this review we provide an overview of melanocytic transformation into malignant melanoma and key molecular events that occur during this evolution. A better understanding of the complex processes entailing cancer cell dissemination will improve the mechanistic driven design of therapies that target specific steps involved in cancer metastasis to improve clinical response rates and overall survival in all cancer patients.

Nanomaterials have been commonly employed to enhance the performance of polymeric membrane materials that are used in several industrial applications. Carbon nanotubes (CNTs) have gained notable attention over the years for use in membrane technology due to their anti-biofouling properties, salt rejection capability, exceptional electrical conductivity, and mechanical properties. This paper aims to discuss some of the recent applications of CNTs in membrane technology and their effect on a larger scale. The paper reviews successful case studies of incorporation of CNTs in membranes and their impact on water purification, desalination, gas separations, and energy storage, in an effort to provide a better understanding of their capabilities. Regarding the future trends of this technology, this review emphasizes improving the large-scale production processes and addressing environmental and health-related hazards of CNTs during production and usage.

Grease is an extraordinarily complex lubricant with a complex material–property relationship, and to shed more light on its importance, we decided to launch the first Special Issue of “Lubricants” purely focusing on the most recent developmental trends of grease applications [...]

Global automotive industries have recently switched development trends from the traditional powertrain mechanical components into the digital transformation of the electrification components in advanced propulsion vehicles. This industrial impact on global development trend into automotive electrification designs has created an emerging technology for new propulsion systems such as hybrid electrical vehicles (HEV) or electrical vehicles (EV). Advanced propulsion systems rising from global guidelines are meant to improve vehicle fuel efficiency and minimize pollution emissions from transportation vehicles. In many HEV or EV advanced system designs, automotive lubricants such as drivetrain fluids or thermal coolants comes into contact with the integrated electric motor (e-motor) and thermal management devices. This leads to the addition of electrical and thermal properties, which must be taken into account on top of conventional lubricant properties. The introduction of electrification components has been targeted for energy efficiency and long-term durability. Automotive industries have asked for the implementation of specialized automotive lubricants or driveline fluids to allow for appropriate thermal cooling specifications, present bearing protection, ensure corrosion protection, and offer oxidation and sludge control. This review paper will provide with global insights on future automotive electrification growth trends with respect to innovative driveline lubricants and thermal cooling liquids used in Hybrid/EV vehicles. Coming research activities in innovative driveline fluids will be focused on minimizing friction loss and maximizing hybrid component durability. The major goal of this paper is to underline the future electrification development trends and the required lubricants for advanced Hybrid/EV vehicles. The major section of this paper will be focused on the most important progress of automotive lubrication in the areas of energy conversion effectiveness, driveline trustworthiness, cooling system design and thermal management control. In this review paper, new developments in thermal management fluids have been described to help promote the high-performance cooling system on electrical batteries, motors, and power electronics. In addition, global research activities using novel nanofluids for thermal cooling have the high potential for application to EV/Hybrid technologies. This paper has reviewed the state-of-art thermal management technology used for extending driving range and durability of EV/Hybrid vehicles. At the end of this paper, using high promising nanofluids for thermal cooling in fuel cell components will be illustrated to demonstrate this potential application in EV/Hybrid vehicles.

Abstract Introduction This study determined whether blood DNA methylation (DNAm) patterns differentiate individuals with presymptomatic dementia compared to controls. Methods DNAm was measured in 73 individuals prior to dementia diagnosis and 87 cognitively healthy controls matched for age, sex, smoking, education, and baseline cognition. DNAm was also measured at 3 years follow‐up in 25 dementia cases, and 24 controls. Results Cases and controls differed in DNAm (unadjusted P

Primary energy has become a vital part of society—from mobility, heating, and cooling to refrigeration to preserve food as well as for simple communication methods, such as texting. As such, pollution and environmental concerns regarding the impact of human activities have become mainstream and efforts have been made to reduce solid wastes as well as CO2 and greenhouse gas emissions. Renewable energy is almost synonymous with environmentally friendly. While energy conversion from fossil fuels and natural gases is responsible for most of the pollution (CO2, NOx, SO2, particulate matter (PM), etc.) in modern society, these processes also generated 86% of global primary energy in 2019. Furthermore, as humans become more dependent on energy, power demands will only increase with time. Material hunger represents another little perceived dependency of human prosperity. The longevity of products and goods is crucial to limit CO2eq emissions associated with material streams. This paper will focus on two relationships: that of CO2 and friction, and that of sustainability and wear protection.

Electric vehicle sales are growing globally in response to the move towards a greener environment and a reduction in greenhouse gas emissions. As in any machine, grease lubricants will play a significant role in the component life of these new power plants and drivetrains. In this paper, the role of grease lubrication in electric vehicles (EVs) and hybrid vehicles (HVs) will be discussed in terms of performance requirements. Comparisons of grease lubrication in EVs and HVs for performance requirements to current internal combustion engines (ICEs) will be reviewed to contrast the major differences under different operating conditions. The operating conditions for grease lubrication in these EVs and HVs are demanding. Greases formulated and manufactured to meet specific performance specifications in EVs and HVs, which will operate within these specific electrification components, will be reviewed. Specifically, the thermal and electrified effects from the higher operating temperatures and electromagnetic fields on lubricant degradation, rheology, elastomer compatibility, and corrosion protection of the grease need to be evaluated to accurately meet the performance requirements for EVs and HV. The major differences between EVs and conventional ICEVs can be grouped into the following technical areas: energy efficiency, noise, vibration, and harshness (NVH), the presence of electrical current and electromagnetic fields from electric modules, sensors and circuits, and bearing lubrication. Additional considerations include thermal heat transfer, seals, corrosion protection, and materials’ compatibility. The authors will review the future development trends of EVs/HVs on driveline lubrication and thermal management requirements. The future development of electric vehicles will globally influence the selection and development of gear oils, coolants, and greases as they will be in contact with electric modules, sensors, and circuits and will be affected by electrical current and electromagnetic fields. The increasing presence of electrical parts in EVs/HVs will demand the corrosion protection of bearings and other remaining mechanical components. Thus, it is imperative that specialized greases should be explored for specific applications in EVs/HVs to ensure maximum protection from friction, wear, and corrosion to guarantee the longevity of the operating automobile. Low-viscosity lubricants and greases will be used in EVs to achieve improvements in energy efficiency. However, low-viscosity fluids reduce the film thickness in the driveline application. This reduced film thickness increases the operating temperature and reduces the calculated fatigue life of the bearings. Bearing components for EVs/HVs will be even more crucial as original equipment manufacturers (OEMs) specify these low-viscosity fluids. The application of premium bearing components using low-viscosity grease will leverage materials, bearing geometries, and surface topography to combat the impact of low-viscosity lubricants. In addition, EVs and HVs will create their own NVH challenges. Wind and road noise are more prominent, with no masking noise from the ICE. Increasing comfort, quality, and reliability issues will be more complicated with the introduction of new electrified powertrain and E-driveline subsystems. This paper elaborates on the current development trends and industrial test standard for the specified grease used for electrical/hybrid driveline lubrication.

Many industrial processes are dependent on the proper application of modern tribological knowledge for the purposes of maintaining equipment integrity and minimizing total energy losses. Consequently, the development of modern lubricants is vital for satisfying growing performance standards and increasingly stringent environmental regulations. Industrial lubricants are regulated based on demanding technical requirements and characteristics, such as high viscosity index, hydraulic stability, corrosion prevention, thermal stability, wide operating temperature ranges, demulsibility, and oxidative stability. Escalating environmental and sustainability concerns have shifted significance towards non-technical criteria for the evaluation of lubricants. Biodegradability and renewability are two influential factors in the discussion regarding the long-term sustainability of future tribological applications. Emphasis is placed on the development of environmentally friendly, non-toxic, and biodegradable lubricants that would minimize industrial pollution associated with oil-related spills and leakages. Bio-based lubricants, manufactured from renewable, organic resources, present themselves as viable alternatives to traditional petroleum-based lubricants. A major section of this review paper will provide a comparative analysis of renewable resource-based lubricants and mineral oil-based lubricants in terms of their chemical properties and respective advantages. Further discussion concerning biolubricants and use of non-edible plant feedstocks will highlight the clear economic and environmental incentives of implementing modern tribological knowledge. This review paper will conclude with the examination of the obstacles that modern day biolubricants must overcome and the future expectations of green tribology.

Grease is highly susceptible to degradation due to regular usage and the severity of the operating conditions. Degradation can negatively impact the performance of grease-lubricated machinery, demanding frequent maintenance to avoid premature failure of machine elements. Quantification of grease degradation has proven to be a formidable task, for which no accepted standards are currently available. In this paper, we extend the results of a novel approach developed recently for the evaluation of the water-resistant property in grease to quantify degradation. The methodology is based on measurements of the contact angle of a water droplet on the surface of a sample of grease. We report the results of extensive tests performed on different grades of lithium complex greases to evaluate the variation of contact angle values with the composition of grease. The measurements were compared with penetrometer readings to quantify a relationship between the grease consistency and contact angle. Detailed study results are also presented on three types of greases sheared in a grease worker for a different number of strokes: contact angle and the yield stress values were measured and compared. Finally, the tribological characteristics were determined for two greases that exhibited a low or high change in their contact angles.

High temperature tribology is considered to begin from a minimum temperature of 300–350 °C, where organic base oils and polymers begin to decompose, until a temperature of 1000 °C. In this field of tribology, tests are typically run under dry or solid-state friction, unless a solid lubricant is used, since most lubricants will oxidize or break down when exposed to these extreme temperatures. Therefore, this form of tribotesting is useful to determine the friction, wear, and other tribological characteristics of coatings, ceramics, alloys, cermets, and similar materials. Additionally, high temperature tribology is important to further understand the frictional interactions and adhesive behavior of contacts that operate at these high temperatures. When considering measurements of the tribological parameters in a high temperature application, the standard Schwingung, Reibung, Verschleiž (SRV) (Oscillating, friction, wear, in English) reciprocating, linear-oscillatory tribometer can be modified for testing temperatures of up to 1000 °C by using a high temperature heating block. With this configuration, the instrument can accurately monitor many parameters of the tribosystem, such as coefficient of friction, electrical resistance, zero stroke point, sliding speed, and others. As a result, the SRV instrument is shown to be a powerful tool for high temperature tribotesting. This paper will provide an overview of this high temperature tribology test rig and will discuss its versatility and efficacy, and will show how it can effectively be implemented in both research and practical applications for the development of various coatings and other high temperature tribological contacts.

Artificial intelligence and, in particular, machine learning methods have gained notable attention in the tribological community due to their ability to predict tribologically relevant parameters such as, for instance, the coefficient of friction or the oil film thickness. This perspective aims at highlighting some of the recent advances achieved by implementing artificial intelligence, specifically artificial neutral networks, towards tribological research. The presentation and discussion of successful case studies using these approaches in a tribological context clearly demonstrates their ability to accurately and efficiently predict these tribological characteristics. Regarding future research directions and trends, we emphasis on the extended use of artificial intelligence and machine learning concepts in the field of tribology including the characterization of the resulting surface topography and the design of lubricated systems.

The complex nature of slip-rolling contacts in many applications such as gear tooth flanks, rolling bearings, and heavy machinery often makes determining the friction and wear properties, as well as the fatigue resistance, of tribosystems difficult. The establishment of the tribological profile of a tribocouple under high Hertzian contact pressure and under slip-rolling will allow for the measurement and comparison of friction and wear coefficients as well as slip-rolling resistance by continuously monitoring the wear rate, coefficient of friction, temperature, oil film thickness, and/or electrical contact resistance using high-resolution signal analysis (HRA). A twin disc system can provide insight into the adhesive behavior of material and lubricant products such as alternative base oils and additives, ceramics, alloys, and thin film coatings. The strength and endurance of these products are often characterized through fatigue and resistance tests, which apply high Hertzian contact pressures to the rolling contact until seizure or failure is obtained. The further observation of the formation of tribofilms on the surface of contact yields information about the reactivity and thermochemical properties of additives. This review aims to illustrate how the implementation of different screening methodologies can be used as a meaningful tool for assessing the aforementioned tribological profile properties for the development of slip-rolling tribosystems.

When looking in detail at analyses of the tribological load-carrying capacity of lubricants, it becomes apparent that an exclusive evaluation of the development of the coefficient of friction cannot provide any sufficient criteria for determining the occurrence of adhesive failure. This is due on the one hand to the increasing complexity of lubricant formulae, and on the other hand to the increasing power capacity of modern drive and control concepts in the construction of tribometers. For this reason, it is urgently needed to examine the adhesive processes and their detection in more detail with the help of appropriate tribological values and criteria. The evolution of the friction can be coupled with the stroke, contact resistance, and other parameters. Besides, from new criteria for adhesive failure, which were compiled by the workgroup for the relevant ISO, DIN, and ASTM standards, this contribution discusses the inclusion of additional parameters. The SRV® test system—where SRV stands for the German acronym for oscillation, friction, and wear—is one that was developed to analyze adhesive failure from many measurements alongside the coefficient of friction. Testing with the SRV® system is done via step tests with standardized procedures and parameters, which are in accordance with ASTM test methods. The system continuously monitors electrical resistance, zero stroke position signals, temperature, and other measurements, and can derive further parameters that also help to identify adhesive failure and other adhesive events. These dimensionally reduced parameters can provide new insight on the mechanism of the adhesive behavior. This paper aims to discuss how the interpretation of these step tests beyond the development of coefficient of friction can lead to new knowledge and insight in tribological research, and explores the applicability of Stribeck’s theory to the oscillatory and reciprocating motion utilized in the SRV® tribometer.

The piston group is responsible for contributing to ~50% of the frictional losses of an engine, which ultimately leads to the waste of fuel. This coupled with the fact that gasoline is a finite resource linked to CO2-emissions, there is an increased demand of higher performance vehicles, which coincidently further loads the piston ring. As of yet, there are plenty of studies that already study the piston ring’s contact with the cylinder liner. However, this study focuses on a cost-effective Schwing, Reib, Verschleiss (SRV) instrumentation that allows to pre-screen lubricants, additives, materials and coatings for their friction, wear and load carrying capacity including scuffing resistance. As a result of the pre-screening conducted outside of engine by using the SRV instrument, it brings us to the following conclusion: the PVD CrN-TiN 1º Group coating on the piston ring produces the least wear, as well as the lowest coefficient of friction. Moreover, it is concluded that a coating that is based from CrN and TiN allows the piston ring to perform better in engine settings. A continued understanding of the piston-cylinder-contact assembly only helps engineers, scientists and any other stakeholder to improve on the piston ring and cylinder liner interaction.

Background and aims: Endoscopic ultrasound with fine needle aspiration (EUS-FNA) has become the standard of care in the evaluation of solid pancreatic lesions. Limited data exist on interobserver agreement (IOA) among cytopathologists in assessing solid pancreatic EUS-FNA specimens. This study aimed to evaluate IOA among cytopathologists in assessing EUS-FNA cytology specimens of solid pancreatic lesions using a novel standardized scoring system and to assess individual clinical and cytologic predictors of IOA. Methods: Consecutive patients who underwent EUS-FNA of solid pancreatic lesions at a tertiary care referral center were included. EUS-FNA slides were evaluated by four blinded cytopathologists using a standardized scoring system that assessed final cytologic diagnosis and quantitative (number of nucleated/diagnostic cells) and qualitative (bloodiness, inflammation/necrosis, contamination, artifact) cytologic parameters. Final clinical diagnosis was based on final cytology, surgical pathology, or 1-year clinical follow-up. IOA was calculated using multi-rater kappa (κ) statistics. Bivariate analyses were performed comparing cases with and without uniform agreement among the cytopathologists followed by logistic regression with backward elimination to model likelihood of uniform agreement. Results: Ninety-nine patients were included (49 % males, mean age 64 years, mean lesion size 26 mm). IOA for final diagnosis was moderate (κ = 0.45, 95 % confidence interval (CI) 0.4 – 0.49) with minimal improvement when combining suspicious and malignant diagnoses (κ = 0.54, 95 %CI 0.49 – 0.6). The weighted kappa value for overall diagnosis was 0.65 (95 %CI 0.54 – 0.76). IOA was slight to fair (κ = 0.04 – 0.32) for individual cytologic parameters. A final clinical diagnosis of malignancy was the most significant predictor of agreement [OR 3.99 (CI 1.52 – 10.49)]. Conclusions: Interobserver agreement among cytopathologists for pancreatic EUS-FNA specimens is moderate-substantial for the final cytologic diagnosis. The final clinical diagnosis of malignancy was the strongest predictor of agreement. These results have significant implications for patient management and need to be validated in future trials.

Background and aims: Endoscopic ultrasound-guided biliary drainage (EUS-BD) has emerged as an alternative to traditional radiologic and surgical drainage procedures after failed endoscopic retrograde cholangiopancreatography (ERCP). However, prospective multicenter data are lacking. The aims of this study were to prospectively assess the short- and long-term efficacy and safety of EUS-BD in patients with malignant distal biliary obstruction. Patients and methods: Consecutive patients at 12 tertiary centers (5 US, 5 European, 1 Asian, 1 South American) with malignant distal biliary obstruction and failed ERCP underwent EUS-BD. Technical success was defined as successful stent placement in the desired position. Clinical success was defined as a reduction in bilirubin by 50 % at 2 weeks or to below 3 mg/dL at 4 weeks. Adverse events were prospectively tracked and graded according to the American Society for Gastrointestinal Endoscopy (ASGE) lexicon’s severity grading system. Overall survival and duration of stent patency were calculated using Kaplan–Meier analysis. Results: A total of 96 patients (mean age 66 years, female 45 %, pancreatic cancer 55 %) underwent EUS-BD. Stent placement (technical success) was achieved in 92 (95.8 %) patients (metallic stent 84, plastic stent 8). Mean procedure time was 40 minutes. Clinical success was achieved in 86 (89.5 %) patients. A total of 10 (10.5 %) adverse events occurred: pneumoperitoneum (n = 2), sheared wire (n = 1), bleeding (n = 1), bile leak (n = 3), cholangitis (n = 2), and unintentional perforation (n = 1); 4 graded as mild, 4 moderate, 1 severe, and 1 fatal (due to perforation). A total of 38 (44 %) patients died of disease progression during the study period. The median patient survival was 167 days (95 %CI 112 – 221) days. The 6-month stent patency rate was 95 % (95 %CI 94.94 – 95.06 %) and the 1-year stent patency was 86 % (95 %CI 85.74 – 86.26 %). Conclusion: This study on EUS-BD demonstrates excellent efficacy and safety of EUS-BD when performed by experts. Study registration: NCT01889953