Constitutive modeling of multi-stimuli-responsive shape memory polymers with multi-functional capabilities

Nowadays, shape memory polymers (SMPs)-based devices are required to be much smarter to produce large shape memory recovery and recovery force with lower working temperatures. They could play a vital role in the advancement of soft robot manipulators, biomedical tools and wearable devices where the working temperatures is a key challenge and must be around the body temperature, or in sustainable smart systems with low energy consumption. The aim of this paper is to introduce thermo-electro-magneto-responsive fibrous SMPs (TEMFSMPs) as a new class of SMPs with highly enhanced shape recovery and recovery force and reduced working temperature. A three-dimensional constitutive model is developed to simulate thermo-electro-magneto-visco-hyperelastic behaviors of SMPs under large deformation for the first time. Constitutive relations are derived by adopting an electro-magneto-visco-hyperelasticity theory and implementing it in a thermo-mechanical cycle of SMPs. To improve the strength of thermo-electro-magneto-responsive SMPs, a bunch of fibers is also embedded into the SMP matrix. Then, the proposed model for thermo-electro-magneto-responsive fibrous shape memory polymers (TEMFSMPs) under uniaxial tension and complex loading regimes such as simultaneous torsion and extension are solved semi-analytically. In addition, the thermo-mechanical response through the proposed model is validated via available SMP experimental tests. Numerical results reveal that electro-magnetic features can significantly enhance shape memory recovery and recovery force of TEMFSMPs and lower their working temperatures. It is found that the electro-magnetic field, the orientation, and stiffness of fibers can effectively be set to tune the shape memory effect and bio-applicability of TEMFSMPs with highly enhanced stress/strain recovery and reduced working temperature

Importance of Magnesium Status in COVID-19

A large amount of published research points to the interesting concept (hypothesis) that magnesium (Mg) status may have relevance for the outcome of COVID-19 and that Mg could be protective during the COVID disease course. As an essential element, Mg plays basic biochemical, cellular, and physiological roles required for cardiovascular, immunological, respiratory, and neurological functions. Both low serum and dietary Mg have been associated with the severity of COVID-19 outcomes, including mortality; both are also associated with COVID-19 risk factors such as older age, obesity, type 2 diabetes, kidney disease, cardiovascular disease, hypertension, and asthma. In addition, populations with high rates of COVID-19 mortality and hospitalization tend to consume diets high in modern processed foods, which are generally low in Mg. In this review, we review the research to describe and consider the possible impact of Mg and Mg status on COVID-19 showing that (1) serum Mg between 2.19 and 2.26 mg/dL and dietary Mg intakes > 329 mg/day could be protective during the disease course and (2) inhaled Mg may improve oxygenation of hypoxic COVID-19 patients. In spite of such promise, oral Mg for COVID-19 has thus far been studied only in combination with other nutrients. Mg deficiency is involved in the occurrence and aggravation of neuropsychiatric complications of COVID-19, including memory loss, cognition, loss of taste and smell, ataxia, confusion, dizziness, and headache. Potential of zinc and/or Mg as useful for increasing drug therapy effectiveness or reducing adverse effect of anti-COVID-19 drugs is reviewed. Oral Mg trials of patients with COVID-19 are warranted

Computational Polyethylene-Ceramic Composite Plate Design and Optimization

A composite designed Ultra High Molecular Weight Polyethylene (UHMWPE) reinforced by a material with a failure mode that will strengthen the system may significantly improve on modern armor designs. UHMWPE is considerably less dense than steel or high density ceramics. It is reasonable to consider making improvements to the weight-performance of armor by using the lower density UHMWPE and combining it with inserts of a high-density ceramic. A cellular ceramic encapsulated by rubber may significantly increase the amount of kinetic energy a composite will absorb through a phase transition. It is theorized that a series of ceramic inserts distributed in a polymer matrix will result in an increased impact resistance. Shock propagation in the ceramic will be minimal, and the elastomeric properties of the polymer will provide maximum tensile support. The ceramic inserts will act as a stress concentrator and physical resistor to the impacting object. When the ceramic inserts are shattered by the impactor they will impart a resistive force by forcing additional deformation in the polymer matrix. Study of design variations by examination of multiple geometries for the ceramic inserts will maximize the impact resistance of the structure. The resistance of the structure is enhanced by providing a multi-dimensional failure mode. The ceramic, once shattered, will still occupy space, forcing additional plastic deformation, and additional deformation in the impactor

Epidemiology of West Nile Virus in the Eastern Mediterranean region: A systematic review

Background: West Nile Virus (WNV), a member of the genus Flavivirus, is one of the most widely distributed arboviruses in the world. Despite some evidence for circulation of WNV in countries summarized by the World Health Organization as the Eastern Mediterrian Region Office (EMRO), comprehensive knowledge about its epidemiology remains largely unknown. This study aims to provide a concise review of the published literature on WNV infections in the Eastern Mediterranean regional office of WHO (EMRO). Methodology/principal findings: A systematic review of WNV prevalence studies on humans, animals and vectors in the EMRO region was performed by searching: Web of Science, Science Direct, Scopus, PubMed, Embase and Google Scholar. Finally, 77 citations were included, comprising 35 seroprevalence studies on general population (24460 individuals), 15 prevalence studies among patients (3439 individuals), 22 seroprevalence studies among animals (10309 animals), and 9 studies on vectors (184242 vector species). Of the 22 countries in this region, five had no data on WNV infection among different populations. These countries include Kuwait, Bahrain, Oman, Syria and Somalia. On the other hand, among countries with available data, WNV-specific antibodies were detected in the general population of all investigated countries including Djibouti (0.3-60), Egypt (1-61), Iran (0-30), Iraq (11.6-15.1), Jordan (8), Lebanon (0.5-1), Libya (2.3), Morocco (0-18.8), Pakistan (0.6-65.0), Sudan (2.2-47), and Tunisia (4.3-31.1). WNV RNA were also detected in patient populations of Iran (1.2), Pakistan (33.3), and Tunisia (5.3 -15.9). WNV-specific antibodies were also detected in a wide range of animal species. The highest seropositivity rate was observed among equids (100 in Morocco) and dogs (96 in Morocco). The highest seroprevalence among birds was seen in Tunisia (23). In addition, WNV infection was detected in mosquitoes (Culex, and Aedes) and ticks (Argas reflexus hermanni). The primary vector of WNV (Culex pipiens s.l.) was detected in Djibouti, Egypt, Iran and Tunisia, and in mosquitoes of all these countries, WNV was demonstrated. Conclusions: This first systematic regional assessment of WNV prevalence provides evidence to support the circulation of WNV in the EMRO region as nearly all studies showed evidence of WNV infection in human as well as animal/vector populations. These findings highlight the need for continued prevention and control strategies and the collection of epidemiologic data for WNV epidemic status, especially in countries that lack reliable surveillance systems. © 2019 Eybpoosh et al

Closed-Loop Recycling of Copper from Waste Printed Circuit Boards Using Bioleaching and Electrowinning Processes

International audienceIn the present study, a model of closed-loop recycling of copper from PCBs is demonstrated, which involves the sequential application of bioleaching and electrowinning to selectively extract copper. This approach is proposed as part of the solution to resolve the challenging ever-increasing accumulation of electronic waste, e-waste, in the environment. This work is targeting copper, the most abundant metal in e-waste that represents up to 20% by weight of printed circuit boards (PCBs). In the first stage, bioleaching was tested for different pulp densities (0.25–1.00% w/v) and successfully used to extract multiple metals from PCBs using the acidophilic bacterium, Acidithiobacillus ferrooxidans. In the second stage, the method focused on the recovery of copper from the bioleachate by electrowinning. Metallic copper foils were formed, and the results demonstrated that 75.8% of copper available in PCBs had been recovered as a high quality copper foil, with 99 + % purity, as determined by energy dispersive X-ray analysis and Inductively-Coupled Plasma Optical Emission Spectrometry. This model of copper extraction, combining bioleaching and electrowinning, demonstrates a closed-loop method of recycling that illustrates the application of bioleaching in the circular economy. The copper foils have the potential to be reused, to form new, high value copper clad laminate for the production of complex printed circuit boards for the electronics manufacturing industry. Graphic Abstract: [Figure not available: see fulltext.] © 2020, The Author(s)

Educational sessions in pharmacovigilance: What do the doctors think?

Background: The aim of this study was to determine physicians"opinion regarding pharmacovigilance feedback sessions. A survey was conducted in a teaching hospital, and the physicians who attended the sessions were invited to participate by filling out a structured questionnaire. All sessions included a review of adverse drug reactions identified at the hospital and information on pharmacovigilance issues (news on warnings released by regulatory agencies or drug toxicity problems identified by recently published studies in medical journals). The survey questions were related to the interest, satisfaction, and belief in the utility of the sessions. A Likert scale (0-10 points) was used to assess physicians" opinions. Findings: A total of 159 physicians attended the sessions and 115 (72.3%) participated in the survey. The mean (SD) age was 38.9 (12.1) years, and 72 (62.6%) were men. The mean (SD) scores of interest, satisfaction with the information provided, and belief in the utility of these sessions were 7.52 (1.61), 7.58 (1.46), and 8.05 (1.38) respectively. Significant differences were observed among physicians according to medical category and speciality in terms of interest, satisfaction, and belief in the utility of those sessions. Conclusions: Educational activities for physicians, such as feedback sessions, can be integrated into the pharmacovigilance activities. Doctors who attend the sessions are interested in and satisfied with the information provided and consider the sessions to be useful. Additional studies on the development and effectiveness of educational activities in pharmacovigilance are necessary

Percentage of Patients with Preventable Adverse Drug Reactions and Preventability of Adverse Drug Reactions – A Meta-Analysis

BACKGROUND: Numerous observational studies suggest that preventable adverse drug reactions are a significant burden in healthcare, but no meta-analysis using a standardised definition for adverse drug reactions exists. The aim of the study was to estimate the percentage of patients with preventable adverse drug reactions and the preventability of adverse drug reactions in adult outpatients and inpatients. METHODS: Studies were identified through searching Cochrane, CINAHL, EMBASE, IPA, Medline, PsycINFO and Web of Science in September 2010, and by hand searching the reference lists of identified papers. Original peer-reviewed research articles in English that defined adverse drug reactions according to WHO's or similar definition and assessed preventability were included. Disease or treatment specific studies were excluded. Meta-analysis on the percentage of patients with preventable adverse drug reactions and the preventability of adverse drug reactions was conducted. RESULTS: Data were analysed from 16 original studies on outpatients with 48797 emergency visits or hospital admissions and from 8 studies involving 24128 inpatients. No studies in primary care were identified. Among adult outpatients, 2.0% (95% confidence interval (CI): 1.2-3.2%) had preventable adverse drug reactions and 52% (95% CI: 42-62%) of adverse drug reactions were preventable. Among inpatients, 1.6% (95% CI: 0.1-51%) had preventable adverse drug reactions and 45% (95% CI: 33-58%) of adverse drug reactions were preventable. CONCLUSIONS: This meta-analysis corroborates that preventable adverse drug reactions are a significant burden to healthcare among adult outpatients. Among both outpatients and inpatients, approximately half of adverse drug reactions are preventable, demonstrating that further evidence on prevention strategies is required. The percentage of patients with preventable adverse drug reactions among inpatients and in primary care is largely unknown and should be investigated in future research

BRCA1 interacts with Nrf2 to regulate antioxidant signaling and cell survival

Oxidative stress plays an important role in cancer development and treatment. Recent data implicate the tumor suppressor BRCA1 in regulating oxidative stress, but the molecular mechanism and the impact in BRCA1-associated tumorigenesis remain unclear. Here, we show that BRCA1 regulates Nrf2-dependent antioxidant signaling by physically interacting with Nrf2 and promoting its stability and activation. BRCA1-deficient mouse primary mammary epithelial cells show low expression of Nrf2-regulated antioxidant enzymes and accumulate reactive oxygen species (ROS) that impair survival in vivo. Increased Nrf2 activation rescues survival and ROS levels in BRCA1-null cells. Interestingly, 53BP1 inactivation, which has been shown to alleviate several defects associated with BRCA1 loss, rescues survival of BRCA1-null cells without restoring ROS levels. We demonstrate that estrogen treatment partially restores Nrf2 levels in the absence of BRCA1. Our data suggest that Nrf2-regulated antioxidant response plays a crucial role in controlling survival downstream of BRCA1 loss. The ability of estrogen to induce Nrf2 posits an involvement of an estrogen-Nrf2 connection in BRCA1 tumor suppression. Lastly, BRCA1-mutated tumors retain a defective antioxidant response that increases the sensitivity to oxidative stress. In conclusion, the role of BRCA1 in regulating Nrf2 activity suggests important implications for both the etiology and treatment of BRCA1-related cancers.FWN – Publicaties zonder aanstelling Universiteit Leide

Adverse Drug Reactions in Children—A Systematic Review

Adverse drug reactions in children are an important public health problem. We have undertaken a systematic review of observational studies in children in three settings: causing admission to hospital, occurring during hospital stay and occurring in the community. We were particularly interested in understanding how ADRs might be better detected, assessed and avoided