The frictional properties of a rough contact interface are controlled by its area of real contact, the dynamical variations of which underlie our modern understanding of the ubiquitous rate-and-state ...friction law. In particular, the real contact area is proportional to the normal load, slowly increases at rest through aging, and drops at slip inception. Here, through direct measurements on various contacts involving elastomers or human fingertips, we show that the real contact area also decreases under shear, with reductions as large as 30%, starting well before macroscopic sliding. All data are captured by a single reduction law enabling excellent predictions of the static friction force. In elastomers, the area-reduction rate of individual contacts obeys a scaling law valid from micrometer-sized junctions in rough contacts to millimeter-sized smooth sphere/plane contacts. For the class of soft materials used here, our results should motivate first-order improvements of current contact mechanics models and prompt reinterpretation of the rate-and-state parameters.
ABSTRACT
Tissue diagnosis of peripheral pulmonary lesions (PPLs) can be challenging. In the past, flexible bronchoscopy was commonly performed for this purpose but its diagnostic yield is suboptimal. ...This has led to the development of new bronchoscopic modalities such as radial endobronchial ultrasound (R‐EBUS), electromagnetic navigation bronchoscopy (ENB) and virtual bronchoscopy (VB). We performed this meta‐analysis using data from previously published R‐EBUS studies, to determine its diagnostic yield and other performance characteristics. Ovid MEDLINE and PubMed databases were searched for R‐EBUS studies in September 2016. Diagnostic yield was calculated by dividing the number of successful diagnoses by the total number of lesions. Meta‐analysis was performed using MedCalc (Version 16.8). Inverse variance weighting was used to aggregate diagnostic yield proportions across studies. Publication bias was assessed using funnel plot and Duval and Tweedie's test. 57 studies with a total of 7872 lesions were included in the meta‐analysis. These were published between October 2002 and August 2016. Overall weighted diagnostic yield for R‐EBUS was 70.6% (95% CI: 68–73.1%). The diagnostic yield was significantly higher for lesions >2 cm in size, malignant in nature and those associated with a bronchus sign on computerized tomography (CT) scan. Diagnostic yield was also higher when R‐EBUS probe was within the lesion as opposed to being adjacent to it. Overall complication rate was 2.8%. This is the largest meta‐analysis performed to date, assessing the performance of R‐EBUS for diagnosing PPLs. R‐EBUS has a high diagnostic yield (70.6%) with a very low complication rate.
Pneumonia is among the leading causes of morbidity and mortality worldwide. Although Streptococcus pneumoniae is the most likely cause in most cases, the variety of potential pathogens can make ...choosing a management strategy a complex endeavor. The setting in which pneumonia is acquired heavily influences diagnostic and therapeutic choices. Because the causative organism is typically unknown early on, timely administration of empiric antibiotics is a cornerstone of pneumonia management. Disease severity and rates of antibiotic resistance should be carefully considered when choosing an empiric regimen. When complications arise, further work-up and consultation with a pulmonary specialist may be necessary.
Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. The hallmarks are the presence of Lewy bodies composed ...mainly of aggregated α‐synuclein and immune activation and inflammation in the brain. The neurotropism of SARS‐CoV‐2 with induction of cytokine storm and neuroinflammation can contribute to the development of PD. Interestingly, overexpression of α‐synuclein in PD patients may limit SARS‐CoV‐2 neuroinvasion and degeneration of dopaminergic neurons; however, on the other hand, this virus can speed up the α‐synuclein aggregation. The review aims to discuss the potential link between COVID‐19 and the risk of PD, highlighting the need for further studies to authenticate the potential association. We have also overviewed the influence of SARS‐CoV‐2 infection on the PD course and management. In this context, we presented the prospects for controlling the COVID‐19 pandemic and related PD cases that, beyond global vaccination and novel anti‐SARS‐CoV‐2 agents, may include the development of graphene‐based nanoscale platforms offering antiviral and anti‐amyloid strategies against PD.
Immune checkpoint inhibitors have been successful across several tumor types; however, their efficacy has been uncommon and unpredictable in glioblastomas (GBM), where <10% of patients show long-term ...responses. To understand the molecular determinants of immunotherapeutic response in GBM, we longitudinally profiled 66 patients, including 17 long-term responders, during standard therapy and after treatment with PD-1 inhibitors (nivolumab or pembrolizumab). Genomic and transcriptomic analysis revealed a significant enrichment of PTEN mutations associated with immunosuppressive expression signatures in non-responders, and an enrichment of MAPK pathway alterations (PTPN11, BRAF) in responders. Responsive tumors were also associated with branched patterns of evolution from the elimination of neoepitopes as well as with differences in T cell clonal diversity and tumor microenvironment profiles. Our study shows that clinical response to anti-PD-1 immunotherapy in GBM is associated with specific molecular alterations, immune expression signatures, and immune infiltration that reflect the tumor's clonal evolution during treatment.
There are several enviable attributes of titanium and its alloys that contribute to their popularity in biomedical devices and equipment, including their rather low modulus, excellent corrosion ...resistance, and biocompatibility, good machinability, formability, and strength comprehensive impact and fatigue. Nevertheless, titanium and its alloys do not meet all medical requirements due to its unique properties and alloys, so surface modifications must be made to enhance mechanical, chemical, and biological characteristics. As a review of biomedical engineering, this article discusses specific polymers for coating applications as well as various polymer coatings for functionalization improvements. The versatility of biopolymer coatings makes them extremely appropriate for a broad range of biological uses. To enhance the engineering of tissue and drug delivery, this study summarized and analyzed the most recent advances in biopolymer coatings. Surface qualities of polymer coatings can be adjusted to meet specific criteria for various biomedical applications or integrated with new capabilities. Moreover, polymer coatings containing different inorganic ions can enhance the growth of tissue, proliferation of cells, healing, as well as the transfer of biomolecules, like active molecules, agents of antimicrobial, factors of growth, and medications.
Highlights
Surface modification avenues of Ti materials as orthopedic replacements are critically reviewed.
Basic descriptions of titanium and titanium alloys are presented.
Advances in the corrosion behavior of biomedical titanium alloys are thoroughly scrutinized.
Fundamental methods based on mechanical, physical, and chemical principles for biopolymer coatings are particularly presented.
Main biopolymer coatings types that are used on titanium surfaces are reviewed.
The groups of biopolymer coatings.
For last one decade, scientists are working for developing nano anti-cancer drugs with claim of ideal ones due to their targeted chemotherapic nature. These drugs have many beneficial properties such ...as targeted drug delivery and gene therapy modalities with minimum side effects. This article describes pros and cons and future perspectives of nano anti-cancer drugs. Efforts have been made to address importance, special features, toxicities (general, blood identities, immune system and environmental) and future perspectives of nano anti-cancer drugs. It was concluded that nano anti-cancer drugs may be magic bullet drugs for cancer treatment leading to bright future of the whole world.
Purpose This paper aims to develop precise statements (standards) to describe the knowledge and skills that should be possessed by Islamic education (IE) teacher candidates who receive their initial ...preparation in various international higher-education institutions. These statements must be compatible with the requirements and guidelines for building specialized standards set by the Council for Accreditation of Educator Preparation (CAEP), so that they can be used for accreditation and improving quality. Design/methodology/approach Two panels of IE experts participated in developing and validating the standards, using a combination of Delphi and content validity methods. Alongside this research activity, management activity ensured that the process ran smoothly, as the researcher coordinated panels, allocated resources and tracked progress during standard development. Findings Twenty-six components divided into five standards were developed into a final list based on the panels. Originality/value This study provides standards for the preparation of IE teachers in higher-education institutions that can be applied in different countries and geographical regions. Furthermore, it aims to make the subject of IE more comparable with other academic disciplines, and appropriate for CAEP accreditation.
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