Developing transition metal dichalcogenides as electrocatalysts has attracted great interest due to their tunable electronic properties and good thermal stabilities. Herein, we propose a PdTe2 ...bilayer as a promising electrocatalyst candidate towards the oxygen reduction reaction (ORR), based on extensive investigation of the electronic properties of PdTe2 thin films as well as atomic-level reaction kinetics at explicit electrode potentials. We verify that under electrochemical reducing conditions, the electron emerging on the electrode surface is directly transferred to O2 adsorbed on the PdTe2 bilayer, which greatly reduces the dissociation barrier of O2, and thereby facilitates the ORR to proceed via a dissociative pathway. Moreover, the barriers of the electrochemical steps in this pathway are all found to be less than 0.1 eV at the ORR limiting potential, demonstrating fast ORR kinetics at ambient conditions. This unique mechanism offers excellent energy efficiency and four-electron selectivity for the PdTe2 bilayer, and it is identified as a promising candidate for fuel cell applications.
We aim to quantitatively synthesise available epidemiological evidence on the prevalence rates of workplace violence (WPV) by patients and visitors against healthcare workers. We systematically ...searched PubMed, Embase and Web of Science from their inception to October 2018, as well as the reference lists of all included studies. Two authors independently assessed studies for inclusion. Data were double-extracted and discrepancies were resolved by discussion. The overall percentage of healthcare worker encounters resulting in the experience of WPV was estimated using random-effects meta-analysis. The heterogeneity was assessed using the I 2 statistic. Differences by study-level characteristics were estimated using subgroup analysis and meta-regression. We included 253 eligible studies (with a total of 331 544 participants). Of these participants, 61.9% (95% CI 56.1% to 67.6%) reported exposure to any form of WPV, 42.5% (95% CI 38.9% to 46.0%) reported exposure to non-physical violence, and 24.4% (95% CI 22.4% to 26.4%) reported experiencing physical violence in the past year. Verbal abuse (57.6%; 95% CI 51.8% to 63.4%) was the most common form of non-physical violence, followed by threats (33.2%; 95% CI 27.5% to 38.9%) and sexual harassment (12.4%; 95% CI 10.6% to 14.2%). The proportion of WPV exposure differed greatly across countries, study location, practice settings, work schedules and occupation. In this systematic review, the prevalence of WPV against healthcare workers is high, especially in Asian and North American countries, psychiatric and emergency department settings, and among nurses and physicians. There is a need for governments, policymakers and health institutions to take actions to address WPV towards healthcare professionals globally.
Epidemiological studies have clarified the potential associations between regular aspirin use and cancers. However, it remains controversial on whether aspirin use decreases the risk of cancers ...risks. Therefore, we conducted an updated meta-analysis to assess the associations between aspirin use and cancers.
The PubMed, Embase, and Web of Science databases were systematically searched up to March 2017 to identify relevant studies. Relative risks (RRs) with 95% confidence intervals (CIs) were used to assess the strength of associations.
A total of 218 studies with 309 reports were eligible for this meta-analysis. Aspirin use was associated with a significant decrease in the risk of overall cancer (RR = 0.89, 95% CI: 0.87-0.91), and gastric (RR = 0.75, 95% CI: 0.65-0.86), esophageal (RR = 0.75, 95% CI: 0.62-0.89), colorectal (RR = 0.79, 95% CI: 0.74-0.85), pancreatic (RR = 0.80, 95% CI: 0.68-0.93), ovarian (RR = 0.89, 95% CI: 0.83-0.95), endometrial (RR = 0.92, 95% CI: 0.85-0.99), breast (RR = 0.92, 95% CI: 0.88-0.96), and prostate (RR = 0.94, 95% CI: 0.90-0.99) cancers, as well as small intestine neuroendocrine tumors (RR = 0.17, 95% CI: 0.05-0.58).
These findings suggest that aspirin use is associated with a reduced risk of gastric, esophageal, colorectal, pancreatic, ovarian, endometrial, breast, and prostate cancers, and small intestine neuroendocrine tumors.
Oxide coatings are corrosion resistant at elevated temperatures. They also show intensive phonon scattering and strong quantum confinement behavior. Such features allow them to be used as new ...materials for thermoelectric energy conversion and temperature measurement in harsh environments. This paper provides an overview on processing thermoelectric oxide coatings via various technologies. The first part deals with the thermoelectricity of materials. A comparison on the thermoelectric behavior between oxides and other materials will be made to show the advantages of oxide materials. In the second part of the paper, various processing technologies for thermoelectric metal oxide coatings in forms of thin film, superlattice, and nanograin powder will be presented. Vapor deposition, liquid phase deposition, nanocasting, solid state approach, and energy beam techniques will be described. The structure and thermoelectric property of the processed metal oxide coatings will be discussed. In addition, the device concept and applications of oxide coatings for thermoelectric energy conversion and temperature sensing will be mentioned. Perspectives for future research will be provided as well.
Drug delivery systems (DDS) are defined as methods by which drugs are delivered to desired tissues, organs, cells and subcellular organs for drug release and absorption through a variety of drug ...carriers. Its usual purpose to improve the pharmacological activities of therapeutic drugs and to overcome problems such as limited solubility, drug aggregation, low bioavailability, poor biodistribution, lack of selectivity, or to reduce the side effects of therapeutic drugs. During 2015–2018, significant progress in the research on drug delivery systems has been achieved along with advances in related fields, such as pharmaceutical sciences, material sciences and biomedical sciences. This review provides a concise overview of current progress in this research area through its focus on the delivery strategies, construction techniques and specific examples. It is a valuable reference for pharmaceutical scientists who want to learn more about the design of drug delivery systems.
This review makes a concise overview of current progress in the research of drug delivery systems that focused on the delivery strategies, construction techniques and specific representatives. Display omitted
Based on (hybrid) first-principles calculations, material properties (structural, electronic, vibrational, optical, and photocatalytic) of van der Waals heterostructures and their corresponding ...monolayers (transition metal dichalcogenides and MXenes) are investigated. MoSe
2
/Zr
2
CO
2
and WSe
2
/Zr
2
CO
2
heterostructures are found to be indirect band gap semiconductors with type-I and type-II band alignment, respectively, while MoSe
2
/Zr
2
CF
2
and WSe
2
/Zr
2
CF
2
are metals. A transition from type-I to type-II band alignment is achieved in MoSe
2
/Zr
2
CO
2
by moderate compressive and tensile strain. Furthermore, absorption spectra are calculated to understand the optical behavior of these systems, whereas red and blue shifts are observed in the positions of the excitonic peaks under tensile and compressive strain in the heterostructures. Photocatalytic studies show that MoSe
2
/Zr
2
CO
2
and WSe
2
/Zr
2
CO
2
heterostructures can oxidize H
2
O/O
2
to O
2
, but unlike their parent monolayers (MoSe
2
, WSe
2
and Zr
2
CO
2
) these heterostructures fail to reduce H
+
to H
2
.
Based on (hybrid) first-principles calculations, material properties (structural, electronic, vibrational, optical, and photocatalytic) of van der Waals heterostructures and their corresponding monolayers (transition metal dichalcogenides and MXenes) are investigated.
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•Different types of intermediate reactions of hydroprocessing pathway were compared.•Single step hydroprocessing of biofuel are mainly done by deoxygenation.•Ni-impregnated zeolite ...catalyst favors the yielding of biofuel in deoxygenation.•Optimum reacting parameters of deoxygenation are kept at 350–400 °C and 1–5 MPa.
Present-day, commercial airlines are getting into the use of bio-jet fuel, by blending vegetable oil derived bio-jet fuel with fossil jet fuel in maximum up to 50%, which is ASTM-certified. In order to reduce the dependency on fossil jet fuel, recent research trend shows that most of the renewable aviation fuel or bio-jet fuel were derived from the complex liquid biomass via hydroprocessing technology. Hence there is a necessity to have an insight into the production technology, typically the hydroprocessing technology. Generally, hydroprocessing technology for the liquid biomass conversion into bio-jet fuel involved multi intermediate steps, such as deoxygenation, cracking and isomerization. This conventional process is further upgraded and simplified into single step reaction, which minimizes the post-treatment effort to be done in every reaction step, and thus reduces the production cost. Moreover, other economic factors such as catalyst price, hydrogen production cost and plant size will also consider as major impacts towards biofuel production scale and cost. Therefore, this paper aims to review the bio-jet fuel conversion technologies in a different perspective, by comparing the hydroprocessing technology of bio-jet fuel (i.e. three-step process, two-step process, single step process), and the effect of reaction variables (i.e. feedstock, catalyst, and reacting gas). The details of outputs for different hydroprocessing technology are also discussed herein. In summary, most research works have achieved positive findings in single step process, by adapting hydrodeoxygenation process in majority. However, there are some limitation and challenges that can be further improved in the single step process, such as exploration on potential feedstock, development of catalyst and optimization of reacting parameters. The energy, environmental and economic analysis on the advanced hydroprocessing of bio-jet fuel are yet to be conducted, in order to compare their merits.
Phase transitions and phase engineering in two-dimensional MoS2 are important for applications in electronics and energy storage. By in situ transmission electron microscopy, we find that H-MoS2 ...transforms to T-LiMoS2 at the early stages of lithiation followed by the formation of Mo and Li2S phases. The transition from H-MoS2 to T-LiMoS2 is explained in terms of electron doping and electron–phonon coupling at the conduction band minima. Both are essential for the development of two-dimensional semiconductor-metal contacts based on MoS2 and the usage of MoS2 as anode material in Li ion batteries.
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