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Large-eddy simulation of a particle-laden flow over an erodible bed is performed to investigate the effect of heavy, saltating particles on turbulence modulation, using the Eulerian–Lagrangian point-particle approach with two-way coupling. The flow into which the solid particles are introduced is a turbulent open channel flow with particle-free friction Reynolds numbers of 3730 and 4200. The inter-particle collisions are not considered, whereas the particle-bed collisions are described by splashing models. Simulation results show that the addition of particles reduces the mean streamwise fluid velocity. The streamwise fluctuating velocity and Reynolds stress are damped while the vertical and spanwise turbulence intensities are enhanced in the near-bed region. The turbulence intensities and Reynolds stress in the outer layer are apparently increased. These effects become more pronounced as the Reynolds number increases. Correlation scales of the turbulence structures increase in the near-bed region and decrease in the outer region. The modulation mechanism of turbulence is revealed. That is, the range and degree of turbulence enhancement by ascending particles in the near-bed region are much larger than those of turbulence attenuation by descending particles, which results in the redistribution of turbulent kinetic energy from the streamwise to the spanwise and vertical directions. This effect extends to the outer region via saltating particles by forming ‘active’ roughness elements. The premultiplied energy spectra of the streamwise velocity show that the enhancement of outer turbulent kinetic energy by saltating particles occurs in a wide range of wavelengths from the intermediate to very large scale.
OBJECTIVE: Since December 2019, SARS-CoV-2 has been discovered in Wuhan and spread rapidly across China and worldwide. Characteristics of infected patients are needed to get insight into the full spectrum of the disease.
METHODS: Epidemiological and clinical information of 1738 diagnosed patients during February 7-26, 2020 in Wuhan Dongxihu Fangcang Hospital were analyzed. 709 patients were followed up on symptom, mental health, isolation site, and medication after discharge.
RESULTS: There were 852 males and 886 females in the cohort. The average age of the patients was 48.8 years. 79.98% of the patients were from Wuhan, Hubei province. The most common initial symptoms were fever, cough and shortness of breath. Among all the patients, 1463 had complications, with respiratory distress as the most common complication. The average duration of hospitalization was 15.95±14.69 days. The most common post-discharge symptom is cough. After discharge, most patients were full of energy, and chose hotel as their self-isolation site. COVID-19 Chinese medicine No.2 prescription is the medication used most commonly by the patients after discharge.
CONCLUSIONS: The population is generally susceptible to SARS-CoV-2. After receiving aggressive treatment of combined Chinese and Western medicine, most patients had a good prognosis and mental health after discharge.
This study explored the clinical effect of employing breast milk oral care for infants who underwent surgical correction of ventricular septal defect.
A prospective randomised controlled study was conducted in a provincial hospital between January, 2020 and July, 2020 in China. Patients were randomly divided into an intervention group (breast milk oral care, n = 28) and a control group (physiological saline oral care, n = 28). The intervention group was given oral nursing using breast milk for infants in the early post-operative period, and the control group was given oral nursing using physiological saline. Related clinical data were recorded and analysed.
There were no significant differences in age, gender, weight, operation time, cardiopulmonary bypass time, or aortic cross-clamping time between the two groups. Compared with the physiological saline oral care group, the mechanical ventilation duration, the length of ICU stay in the breast milk oral care group were significantly shorter. The time of start feeding and total enteral nutrition were significantly earlier in the intervention group than those in the control group. The incidence of post-operative pneumonia in the breast milk oral care group was 3.6%, which was significantly lower than that of the physiological saline oral care group.
The use of breast milk for oral care in infants who underwent surgical correction of VSD can reduce the incidence of post-operative pneumonia and promote the recovery of gastrointestinal function.
Pulmonary arterial hypertension symptoms in systemic lupus erythematosus patients are non-specific and early diagnosis and intervention are challenging. It remains essential to explore risk factors for pulmonary arterial hypertension in systemic lupus erythematosus patients to identify high risk patients and allow intensive monitoring.
From January 2010 to December 2018, 84 patients with systemic lupus erythematosus and pulmonary arterial hypertension and 160 patients with systemic lupus erythematosus but without pulmonary arterial hypertension were enrolled. Clinical manifestations and laboratory test results were compared between the two groups to identify predictors of pulmonary arterial hypertension. Candidate pulmonary arterial hypertension risk factors were further compared among systemic lupus erythematosus-pulmonary arterial hypertension patients with different characteristics.
Among collected patient characteristics, Raynaud’s phenomenon (OR 2.32, 95% CI: 1.17–4.61), digital vasculitis (OR 4.12, 95% CI: 1.48–11.49), pericardial effusion, pulmonary interstitial lesions, positive anti-u1 ribonucleoprotein antibodies, and positive anticardiolipin antibodies immunoglobulin G were associated with significantly higher risk of pulmonary arterial hypertension in systemic lupus erythematosus patients. Among these candidate risk factors, positive anti-u1 ribonucleoprotein antibody was independently associated with severe pulmonary arterial hypertension and more active disease. Digital vasculitis was independently associated with systemic lupus erythematosus alleviation, while pericardial effusion was associated with systemic lupus erythematosus deterioration. Pericardial effusion was associated with longer pulmonary arterial hypertension duration.
The significant association between studied clinical and laboratory indicators and risk of pulmonary arterial hypertension, pulmonary arterial hypertension and systemic lupus erythematosus characteristics suggested that these factors can be used to identify patients at higher risk of pulmonary arterial hypertension and adverse outcomes. Close monitoring may be indicated in patients with these risk factors, especially with more than one risk factor.
The Dayao Paleolithic site, located in Inner Mongolia on the eastern margin of China's vast northwestern drylands, was a lithic quarry-workshop utilized by Pleistocene human migrants through the region. Determining the age of this activity has previously yielded controversial results. Our magnetostratigraphic and OSL dating results suggest the two artifact-bearing paleosols are correlated with MIS 5 and 7, respectively. Correlating paleoclimatic data with marine δ18O records leads us to conclude that two sandy gravel layers containing many artifacts in the lower part of the Dayao sequence were formed during MIS 9 and 11, if not earlier. Our results reveal that the earliest human occupation at the Dayao site occurred before ca. 400 ka during a relatively warm and moist interglacial period, similar to several subsequent occupations, documenting the earliest and northernmost archaeological assemblage yet reported in China's arid northwest. We conclude that the northward and southward displacements of the East Asian summer monsoon rain belt during past interglacial-glacial cycles were responsible for the discontinuous human occupation detected at the Dayao site. The penetration of this precipitation regime into dryland ecologies via the Huanghe (Yellow River) Valley effectively created a corridor for hominin migration into China's arid northwest.
Over recent decades, Chinese giant salamanders Andrias spp. have declined dramatically across much of their range. Overexploitation and habitat degradation have been widely cited as the cause of these declines. To investigate the relative contribution of each of these factors in driving the declines, we carried out standardized ecological and questionnaire surveys at 98 sites across the range of giant salamanders in China. We did not find any statistically significant differences between water parameters (temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, alkalinity, hardness and flow rate) recorded at sites where giant salamanders were detected by survey teams and/or had been recently seen by local respondents, and sites where they were not detected and/or from which they had recently been extirpated. Additionally, we found direct and indirect evidence that the extraction of giant salamanders from the wild is ongoing, including within protected areas. Our results support the hypothesis that the decline of giant salamanders across China has been primarily driven by overexploitation. Data on water parameters may be informative for the establishment of conservation breeding programmes, an initiative recommended for the conservation of these species.
Inflammation might play a role in bipolar disorder (BD), but it remains unclear the relationship between inflammation and brain structural and functional abnormalities in patients with BD. In this study, we focused on the alterations of functional connectivity (FC), peripheral pro-inflammatory cytokines and their correlations to investigate the role of inflammation in FC in BD depression.
In this study, 42 unmedicated patients with BD II depression and 62 healthy controls (HCs) were enrolled. Resting-state-functional magnetic resonance imaging was performed in all participants and independent component analysis was used. Serum levels of Interleukin-6 (IL-6) and Interleukin-8 (IL-8) were measured in all participants. Correlation between FC values and IL-6 and IL-8 levels in BD was calculated.
Compared with the HCs, BD II patients showed decreased FC in the left orbitofrontal cortex (OFC) implicating the limbic network and the right precentral gyrus implicating the somatomotor network. BD II showed increased IL-6 (p = 0.039), IL-8 (p = 0.002) levels. Moreover, abnormal FC in the right precentral gyrus were inversely correlated with the IL-8 (r = −0.458, p = 0.004) levels in BD II. No significant correlation was found between FC in the left OFC and cytokines levels.
Our findings that serum IL-8 levels are associated with impaired FC in the right precentral gyrus in BD II patients suggest that inflammation might play a crucial role in brain functional abnormalities in BD.
More than 50% patients with major depressive disorder (MDD) have severe functional impairment. The restoration of patient functioning is a critical therapeutic goal among patients with MDD. We conducted a systematic review and network meta-analysis to evaluate the efficacy of pharmacological treatments on self-rated functional outcomes using the Sheehan Disability Scale in adults with MDD in randomized clinical trials.
PubMed, EMBASE, PsycINFO, Cochrane Library, and ClinicalTrials.gov were searched from inception to December 10, 2019. Summary statistics are reported as weighted mean differences with 95% confidence intervals. Interventions were ranked using the surface under the cumulative ranking probabilities.
We included 42 randomized controlled trials (RCTs) (n = 18 998) evaluating the efficacy of 13 different pharmacological treatments on functional outcomes, as measured by the Sheehan Disability Scale (SDS). Duloxetine was the most effective pharmacological agent on functional outcomes, followed by (ranked by efficacy): paroxetine, levomilnacipran, venlafaxine, quetiapine, desvenlafaxine, agomelatine, escitalopram, amitriptyline, bupropion, sertraline, vortioxetine, and fluoxetine. Serotonin and norepinephrine reuptake inhibitors were more effective than other drug classes. Additionally, the comparison-adjusted funnel plot suggested the publication bias between small and large studies was relatively low.
Our results indicate that there may be differences across antidepressant agents and classes with respect to self-reported functional outcomes. Validation and replication of these findings in large-scale RCTs are warranted. Our research results will be clinically useful for guiding psychiatrists in treating patients with MDD and functional impairment. PROSPERO registration number CRD42018116663.
A multidisciplinary fieldwork and research project was recently begun at the Yangshang site (220–140 ka), a late Early Paleolithic locale in the western Chinese Loess Plateau. 1696 lithic artifacts and 337 faunal remains were recovered during the excavation. Sedimentological and paleoenvironmental investigations indicate the site preserves a relatively long and minimally disturbed archaeological sequence associated with paleoenvironmental changes during MIS 7–6. A detailed techno-typological analysis of Yangshang's lithic assemblages was undertaken to examine the influence of glacial cycles on late Middle Pleistocene hominin technological strategies in the western Chinese Loess Plateau. The results show that while the Yangshang site is dominated by quartz-based core/flake assemblages typical of most Early Paleolithic sites in North China, the lithic assemblages provide evidence that different provisioning systems existed during the penultimate glaciation. We argue that these shifts reflect changes in land use and mobility that were tied to climate change. Our results suggest that theoretically informed statistical analyses of so-called unchanging and crude lithic technology can yield meaningful evidence for behavioral shifts.
The aim of this study was to investigate the association between daily Se intake and postpartum weight retention (PPWR) among Chinese lactating women, and the impact of their Se nutritional status on infants’ physical development. Se contents in breast milk and plasma collected from 264 lactating Chinese women at the 42nd day postpartum were analysed with inductively coupled plasma MS. Daily Se intake was calculated based on plasma Se concentration. The dietary data of 24-h records on three consecutive days were collected. Infant growth status was evaluated with WHO standards by Z-scores. Linear regression analyses and multinomial logistic regression were conducted to examine the impact of Se disequilibrium (including other factors) on PPWR and growth of infants, respectively. The results indicated that: (1) the daily Se intake of the subjects was negatively associated with their PPWR (B = −0·002, 95 % CI − 0·003, 0·000, P = 0·039); (2) both insufficient Se daily intake (B = −0·001, OR 0·999, 95 % CI 0·998, 1·000, P = 0·014) and low level of Se in milk (B = −0·025, OR 0·975, 95 % CI 0·951, 0·999, P = 0·021) had potential associations with their infants’ wasting, and low level of Se in milk (B = −0·159, OR 0·853, 95 % CI 0·743, 0·980, P = 0·024) had a significant association with their infants’ overweight. In conclusion, the insufficient Se nutritional status of lactating Chinese women was first found as one possible influencing factor of their PPWR as well as low physical development of their offspring.
The prognostic factor for in-hospital mortality in tuberculosis (TB) patients requiring intensive care unit (ICU) care remains unclear. Therefore, a retrospective study was conducted aiming to estimate the in-hospital mortality rate and the risk factors for mortality in a high-burden setting. All patients with culture-confirmed TB that were admitted to the ICU of the hospital between March 2012 and April 2019 were identified retrospectively. Data, such as demographic characteristics, comorbidities, laboratory measures and mortality, were obtained from medical records. The Cox proportional hazards regression model was used to identify prognostic factors that influence in-hospital mortality. A total of 82 ICU patients with confirmed TB were included in the analysis, and 22 deaths were observed during the hospital stay, 21 patients died in the ICU. In the multivariable model adjusted for sex and age, the levels of serum albumin and white blood cell (WBC) count were significantly associated with mortality in TB patients requiring ICU care (all P < 0.01), the hazard ratios were 0.8 (95% confidence interval (CI): 0.7–0.9) per 1 g/l and 1.1 (95% CI: 1.0–1.2) per 1 × 109/l, respectively. In conclusion, in-hospital mortality remains high in TB patients requiring ICU care. Low serum albumin level and high WBC count significantly impact the risk of mortality in these TB patients in China.
We demonstrate an all-optical method for controlling the transverse motion of an ionization injected electron beam in a laser plasma accelerator by using the transversely asymmetrical plasma wakefield. The laser focus shape can control the distribution of a transversal wakefield. When the laser focus shape is changed from circular to slanted elliptical in the experiment, the electron beam profiles change from an ellipse to three typical shapes. The three-dimensional particle-in-cell simulation result agrees well with the experiment, and it shows that the trajectories of these accelerated electrons change from undulating to helical. Such an all-optical method could be useful for convenient control of the transverse motion of an electron beam, which results in synchrotron radiation from orbit angular momentum.
In this paper, we report the study of degradation for a kind of ideal mandrel material called poly-α-methylstyrene based on theoretical and experimental methods. First-principles calculations reveal two types of process: depolymerization and hydrogen-transfer-induced chain scission. The energy barrier for the former (0.68–0.82 eV) is smaller than that for most of the latter (1.39–4.23 eV). More importantly, reaction rates suggest that the former is fast whereas the latter is mostly slow, which can result in a difference of 5–31 orders of magnitude at 550 K. Furthermore, a thermogravimetric experiment shows that the activation energy of 2.53 eV for degradation is between those of fast and slow processes, corresponding to the theoretical average value of multiple reaction paths. Thus, a mandrel degradation model combining fast and slow processes is established at the atomic level. Our work provides a direction for research into the key technology of target fabrication in inertial confinement fusion.
The present study was conducted to test the hypothesis that dietary supplementation with a nano chitosan–zinc complex (CP–Zn, 100 mg/kg Zn) could alleviate weaning stress in piglets challenged with enterotoxigenic Escherichia coli K88 by improving growth performance and intestinal antioxidant capacity. The in vivo effects of CP–Zn on growth performance variables (including gastrointestinal digestion and absorption functions and the levels of key proteins related to muscle growth) and the antioxidant capacity of the small intestine (SI) were evaluated in seventy-two weaned piglets. The porcine jejunal epithelial cell line IPEC-J2 was used to further investigate the antioxidant mechanism of CP–Zn in vitro. The results showed that CP–Zn supplementation increased the jejunal villus height and decreased the diarrhoea rate in weaned piglets. CP–Zn supplementation also improved growth performance (average daily gain and average daily feed intake), increased the activity of carbohydrate digestion-related enzymes (amylase, maltase, sucrase and lactase) and the mRNA expression levels of nutrient transporters (Na+-dependent glucose transporter 1, glucose transporter type 2, peptide transporter 1 and excitatory amino acid carrier 1) in the jejunum and up-regulated the expression levels of mammalian target of rapamycin (mTOR) pathway-related proteins (insulin receptor substrate 1, phospho-mTOR and phospho-p70S6K) in muscle. In addition, CP–Zn supplementation increased glutathione content, enhanced total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-px) activity, and reduced malondialdehyde (MDA) content in the jejunum. Furthermore, CP–Zn decreased the content of MDA and reactive oxygen species, enhanced the activity of T-SOD and GSH-px and up-regulated the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) pathway-related proteins (Nrf2, NAD(P)H:quinone oxidoreductase 1 and haeme oxygenase 1) in lipopolysaccharide-stimulated IPEC-J2 cells. Collectively, these findings indicate that CP–Zn supplementation can improve growth performance and the antioxidant capacity of the SI in piglets, thus alleviating weaning stress.
Visual–Inertial Navigation Systems (VINS) plays an important role in many navigation applications. In order to improve the performance of VINS, a new visual/inertial integrated navigation method, named Sliding-Window Factor Graph optimised algorithm with Dynamic prior information (DSWFG), is proposed. To bound computational complexity, the algorithm limits the scale of data operations through sliding windows, and constructs the states to be optimised in the window with factor graph; at the same time, the prior information for sliding windows is set dynamically to maintain interframe constraints and ensure the accuracy of the state estimation after optimisation. First, the dynamic model of vehicle and the observation equation of VINS are introduced. Next, as a contrast, an Invariant Extended Kalman Filter (InEKF) is constructed. Then, the DSWFG algorithm is described in detail. Finally, based on the test data, the comparison experiments of Extended Kalman Filter (EKF), InEKF and DSWFG algorithms in different motion scenes are presented. The results show that the new method can achieve superior accuracy and stability in almost all motion scenes.
In this paper, the generation of relativistic electron mirrors (REMs) and the reflection of an ultra-short laser off this mirrors are discussed, applying two-dimensional particle-in-cell (2D-PIC) simulations. REMs with ultra-high acceleration and expanding velocity can be produced from a solid nanofoil illuminated normally by an ultra-intense femtosecond laser pulse with a sharp rising edge. Chirped attosecond pulse can be produced through the reflection of a counter-propagating probe laser off the accelerating REM. In the electron moving frame, the plasma frequency of the REM keeps decreasing due to its rapidly expanding. The laser frequency, on the contrary, keeps increasing due to the acceleration of REM and the relativistic Doppler shift from the lab frame to the electron moving frame. Within an ultra-short time interval, the two frequencies will be equal in the electron moving frame, which leads the resonance between laser and REM. The reflected radiation near this interval and the corresponding spectra will be amplified due to the resonance. Through adjusting the arriving time of the probe laser, certain part of the reflected field could be selectively amplified or depressed, leading to the selectively adjusting of the corresponding spectra.
We propose a nonparametric test of significant variables in the partial derivative of a regression mean function. The derivative is estimated by local polynomial estimation and the test statistic is constructed through a variation-based measure of the derivative in the direction of variables of interest. We establish the asymptotic null distribution of the test statistic and demonstrate that it is consistent. Motivated by the null distribution, we propose a wild bootstrap test, and show that it exhibits the same null distribution, whether the null is valid or not. We perform a Monte Carlo study to demonstrate its encouraging finite sample performance. An empirical application is conducted showing how the test can be applied to infer certain aspects of regression structures in a hedonic price model.
The study of enclaves in granitic plutons provides fundamental information on the petrogenesis of their host rocks. Here we combine U–Pb zircon ages, petrography, geochemistry and Nd–Hf isotope composition to investigate the origin of dioritic–granodioritic enclaves and their host granodiorites and biotite granites in the Xuehuading–Panshanchong area, which is a pivotal site to study the Palaeozoic intracontinental orogenic processes of the South China Block. Obtained ages indicate that the host rocks were formed in early Silurian time (c. 432 Ma). The enclaves are fine grained, but with mineral assemblages similar to their hosts and contain amphibole, biotite and plagioclase. All rocks have fractionated rare earth element patterns ((La/Yb)N = 2.86–8.16), except for one biotite granite that has a concave rare earth element pattern ((La/Yb)N = 1.50). Most rocks are depleted in Ta–Nb–Ti, and have negative Eu anomalies and ϵNd(t) (–8.86 to –5.75) and zircon ϵHf(t) (–13.30 to –4.11, except for one, –39.08). We interpret that the enclaves were formed at the borders of magma-ascending conduits, where the mafic mineral crystallization was enhanced by rapid cooling. Conversely, the biotite granites were produced by fractional crystallization from a related granodiorite magma. The sample with a concave rare earth element pattern may have been influenced by hydrothermal fluid–melt interaction. Geochemical modelling suggests that the granodiorites were likely generated by disequilibrium melting of heterogeneous amphibolites in the middle–lower crust. Considering the geological data for the Palaeozoic magmatic rocks in the South China Block, we propose that the Xuehuading–Panshanchong magmatism was likely triggered by piecemeal removal of the thickened lithospheric root and subsequent thermal upwelling of mantle, without a mantle-derived magma contribution to the granites.
Sugarcane brown rust, caused by Puccinia melanocephala, is one of the main diseases of sugarcane in China. The identification and discovery of new resistance genes have important theoretical and practical significance for preventing outbreaks of brown rust and ensuring the sustainable production of sugarcane. To screen for polymorphic simple-sequence repeat (SSR) molecular markers for localization of brown rust resistance genes, we used two populations that are suitable for genetic linkage map construction and mapping of new resistance genes to construct resistant and susceptible genetic pools. We then screened 449 pairs of primers to identify polymorphic SSR markers in the parental lines and the resistant/susceptible genetic pools. The results showed that 25 pairs of primers directed amplification of polymorphic DNA fragments between the parents of the cross combination ‘Yuetang 03-393’ × ‘ROC 24’, and 16 pairs of primers amplified polymorphic fragments between the parents of the cross combination ‘Liucheng 03-1137’ × ‘Dezhe 93-88’. Four pairs of primers (SMC236CG, SCESSR0928, SCESSR0636 and SCESSR2551) amplified polymorphic DNA fragments between the parental lines and the resistant/susceptible genetic pools in ‘Yuetang 03-393’ × ‘ROC 24’. The results of this study will establish a solid foundation for the mapping of new brown rust resistance genes, genetic linkage map construction and the development of closely-associated molecular markers in sugarcane.