We propose a two-step silicon carbide (SiC) solution growth method for dislocation reduction to produce the high-quality silicon carbide SiC crystals. The two-step growth consists of the growth on a ...Si face and a C face. Firstly, seed crystal with low threading dislocation density was prepared by the growth on a Si face utilizing the threading dislocation conversion. Secondly, the growth on the C face was conducted on the prepared seed crystal with low threading dislocation density to reduce the density of basal plane dislocations and keep smooth growth surface. We demonstrate that the two-step growth leads to the reduction of the density for all types of dislocations by two orders of magnitude compared to the initial density of the seed crystal.
•Growth experiment of a low-dislocation-density SiC crystal was performed.•The two-step growth which consists of growth on a Si face and a C face was proposed.•Dislocation density of crystal was two orders of magnitude lower than that of seed.
Contact precautions (CPs) have been widely implemented in hospitals, particularly in intensive care units (ICUs), as the standard approach for managing meticillin-resistant Staphylococcus aureus ...(MRSA). However, the effectiveness of CPs in preventing MRSA transmission remains a subject of debate.
To assess the effectiveness of CPs in reducing MRSA transmission within ICUs.
A comprehensive analysis was conducted using data from 16 sets of parameters collected from 13 field studies investigating the effectiveness of CPs in ICUs, and an epidemiologic model was developed to simulate the dynamics of MRSA incidence in the hospital setting.
The analysis demonstrated a mean reduction of 20.52% (95% confidence interval -30.52 to 71.60%) in the MRSA transmission rate associated with the implementation of CPs. Furthermore, reducing the time-delay of screening tests and increasing the percentage of patients identified with MRSA through screening at admission were found to contribute to the effectiveness of CPs.
Proper implementation of CPs, with a particular emphasis on early identification of MRSA-colonized/infected patients, demonstrated a strong association with reduced MRSA transmission within the hospital setting. However, further research is necessary to investigate the effectiveness and safety of decolonization and other interventions used in conjunction with CPs to mitigate the risk of infection among colonized patients.
One of difficulties to detect abrasive wear in journal bearings through vibration analysis is the lack of obvious fault characteristics in an early stage. To carry out an in-depth investigation on ...the relationship between wear occurred inside and vibration signals acquired outside is meaningful from the diagnostic point of view. In this paper, a tribo-dynamic model is developed for the fluid-asperity interaction in journal bearings. The microscopic pressure fluctuation induced random excitation is derived. The effects of surface roughness and operating condition on the random excitation are investigated. It is found that wear induced narrowband spatial components of journal surface can excite random vibration of bearing. The speed dependent vibrational behaviour is found to be an effective indicator of surface defects.
•A tribo-dynamic model is developed for the fluid-asperity interaction in journal bearings.•Microscopic pressure fluctuation induced random excitation are investigated.•Relationships between surface topography and vibrational behaviours are clarified.•Speed dependent random vibration of the bearing is an effective indicator of surface defects.
We statistically investigate the spectral scalings of magnetic fluctuations at the upstream and downstream regions near the Venusian bow shock and perform a differentiation by shock geometry. Based ...on the Venus Express data, 115 quasi-parallel (
Q
‖
) bow shock crossings and 303 quasi-perpendicular (
Q
⊥
) bow shock crossings are selected. The statistical results suggest that the bow shock tends to modify the upstream spectra flatter to 1/
f
noise in the magnetohydrodynamics (MHD) regime and steeper to turbulence in the kinetic regime after the magnetic fluctuations crossing the bow shock, and this modification for the
Q
‖
and
Q
⊥
bow shocks is basically consistent. However, the upstream spectral scalings are associated with the shock geometry. The changes of the spectral scalings of magnetic fluctuations near the
Q
‖
bow shocks are not as significant as near the
Q
⊥
bow shock crossings. That might result from the fluctuations generated by the backstreaming ions which can escape across the
Q
‖
bow shock into the foreshock. Our results suggest that the energy cascade and dissipation near Venus can be modified by the Venusian bow shock, and the
Q
‖
bow shock plays an important role on the energy injection and dissipation in the solar wind interaction with Venus. The large dispersion of spectral scalings indicates that this fluctuation environment is complicated, and the shock geometry is not the only key factor in the fluctuations across the Venusian bow shock. Other possible factors in the shock modification to the upstream fluctuations will be explored in future.
The May 2008 earthquake in Wenchuan drew attention to the important but largely unrecognised public-health problem of injury-related mortality and morbidity in China. Injuries account for more than ...10% of all deaths and more than 30% of all potentially productive years of life lost due to premature mortality in China. Traffic-related injuries (mainly among cyclists and pedestrians), suicide, drowning, and falls account for 79% of all injury deaths. Rural injury death rates are double those of urban rates and male rates are double those of female rates. Despite an 81% increase in the traffic-related mortality from 1987 to 2006-associated with rapid motorisation-the overall injury mortality decreased by 17%, largely due to a surprising (and unexplained) 57% reduction in the suicide rate. Low-cost prevention measures that are most likely to produce large reductions in injury deaths include enforcement of laws for drinking and driving and for seat belt and helmet use, restriction of access to the most potent pesticides, and teaching children to swim. China needs to improve monitoring of fatal and non-fatal injuries, promote intersectoral collaboration, build institutional capacities, and, most importantly, mobilise community support and political will for investment in prevention. PUBLICATION ABSTRACT
In this paper, the grain growth behavior of Ti(C,N)-based cermet, including the microstructure evolution and sintering kinetics in the sintering process at different temperatures for different ...holding time, was studied experimentally and theoretically. A comprehensive grain growth model for Ti(C,N)-based cermet was established based on the experimental data. Furthermore, different influencing factors of microstructure evolution during sintering for Ti(C,N)-based cermet were investigated systematically by a scanning electron microscope. The results showed that the sintering temperature and holding time have a significant effect on the microstructure evolution of Ti(C,N)-based cermet. The grain growth rate was the fastest at the temperature range of 1300°C to 1400°C. The grain growth rate was reduced slightly at higher temperatures. A comprehensive sintering kinetics model of Ti(C,N)-based cermet during the sintering process was obtained based on the experimental results via nonlinear regression method.
Radiofrequency coblation (RFC) is a relatively new device that has been used in several transoral procedures. Currently, clinical data on its use for excising lingual thyroglossal duct cyst (LTGDC) ...are lacking. Herein, we conducted this retrospective case series to explore the feasibility and efficacy of RFC-assisted transoral surgery (RFC-TOS) in excising LTGDC. A total of 12 LTGDC patients between 2013 and 2020 were retrospectively studied. The cysts of these patients were all fully removed along the boundary to the depth of the hyoid using RFC wands. All surgeries were completed within 30 minutes. Only one patient had an intraoperative blood loss of more than 10 ml. All patients started oral feeding on the day of operation. The mean postoperative hospital stay was only 3.3 days (range 1-8 days). No surgical-related short-term and long-term complications were observed. One patient was lost to follow up, and no recurrences occurred during a mean follow-up period of 52.7 months among the other 11 patients. Therefore, we believe that RFC is a reliable tool in transoral operation for treating LTGDC. LTGDC patients who underwent RFC-TOS showed quick recovery, low risks of complications, and excellent clinical and functional outcomes.
Pesticide residues on plant surfaces are a primary source of pesticide bioaccumulation in crops. In this context, we propose a mechanism-based model for understanding the pesticide fate on the plant ...surface following aerial application, taking into account fate modelling of the pesticide spray solution on the plant surface. Using chlorothalonil as an example, the simulation results revealed that the spray solution dissipated rapidly after aerial application, resulting in the formation of a saturated pesticide solution, which facilitated the diffusion process of the pesticide residue from the plant surface into the peel tissue. The proposed model generated higher simulated residue concentrations in the peel or pulp than the current model, owing to the proposed model's assumption of rapid dissipation of the spray solution. This indicated that the proposed model specified the influence of the spray solution on the plant's exposure to residues via the surface deposition pathway, whereas the current modelling approach presented a generic estimate of the residue dissipation on the plant surface that linked to the residue's fate in the soil.
Abstract
Electron-scale magnetic holes (ESMHs) can dissipate energy and transport electrons in astrophysical plasmas. They are often observed in the solar wind at 1 au, but whether they are locally ...generated remains unclear. Here we investigate the ESMHs in the solar wind at 1 au based on observations of the Magnetospheric Multiscale (MMS) and Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS) P1 spacecraft. There are 47 and 18 ESMH events observed by MMS1 and ARTEMIS P1, respectively, where an isolated ESMH or a train of ESMHs is regarded as an ESMH event. Our findings are as follows: (1) the occurrence rate of the ESMH events observed by MMS1 is much larger than that by ARTEMIS P1, which is located in the upstream solar wind; and (2) the proportion of the train of ESMHs in the ESMH events observed by each spacecraft is much higher in the ion foreshock than that in the undisturbed solar wind. These observations suggest that the terrestrial foreshock is an important source region of the ESMHs at 1 au, while some ESMHs come from the upstream undisturbed solar wind. The generation of these ESMHs can be explained by the electron vortex magnetic hole. Finding out the origin of the electron vortex may help to shed light on the whole chain of their generation and evolution in the foreshock.
Lafora disease (LD) and adult polyglucosan body disease (APBD) are glycogen storage diseases characterized by a pathogenic buildup of insoluble glycogen. Mechanisms causing glycogen insolubility are ...poorly understood. Here, in two mouse models of LD (Epm2a−/− and Epm2b−/−) and one of APBD (Gbe1ys/ys), the separation of soluble and insoluble muscle glycogen is described, enabling separate analysis of each fraction. Total glycogen is increased in LD and APBD mice, which, together with abnormal chain length and molecule size distributions, is largely if not fully attributed to insoluble glycogen. Soluble glycogen consists of molecules with distinct chain length distributions and differential corresponding solubility, providing a mechanistic link between soluble and insoluble glycogen in vivo. Phosphorylation states differ across glycogen fractions and mouse models, demonstrating that hyperphosphorylation is not a basic feature of insoluble glycogen. Lastly, model-specific variances in protein and activity levels of key glycogen synthesis enzymes suggest uninvestigated regulatory mechanisms.
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•Soluble glycogen content and structure: WT-like in Epm2a−/−, Epm2b−/−, Gbe1ys/ys mice•Glycogen hyperphosphorylation is not a general feature of insoluble glycogen•Abnormal chain length and molecule size distributions are limited to insoluble glycogen•Wild-type glycogen molecules vary in average chain length and precipitation propensity
EPM2A, EPM2B, or GBE1 deficiency causes insoluble glycogen accumulation and neurodegenerative diseases. Sullivan et al. show that these defects do not impair the construction of WT-like soluble glycogen. Demonstrating varying chain length distributions and correlating precipitation propensity among WT-glycogen molecules, a mechanistic explanation emerges for the structural characteristics of insoluble glycogen.
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