Vibration characterization of rolling bearings with compound fault features under multiple interference factors.

As a key component of rotating machinery power transmission system, rolling bearings in gas turbines are often required to serve in complex working conditions such as the high speed, the heavy load, the variable load, the variable rotational speed, and so on. The signals of bearing failures are easily drowned out by strong background noise and disturbances of related components. In the mechanical transmission system, the signals of bearing failures are easily submerged by the strong background noise and the disturbance of related components, especially for the composite bearing failures, which seriously hinders the effective identification of the vibration characteristics of the bearing operating state and increases the difficulty of fault diagnosis. In order to investigate the impact of interference on the bearing, through the establishment of rolling bearing composite fault vibration model, analyze the relationship between the vibration signals caused by different types of bearing failures and the corresponding vibration characteristics, to reveal the transmission system of the parts of the perturbation of the main multi-interference factors on the bearing fault signal influence law. The experimental verification shows that disturbance yp(t) caused by the sum of gear meshing frequency, and installation errors of the shaft, and coupling in the transmission system and background noise ni(t), which makes the fault frequency relatively weak and difficult to observe, and makes it difficult to accurately separate the fault information of the bearing. It provides a theoretical basis to solve the problem of damage identification and fault diagnosis of rolling bearings under multi-interference state.

Symptoms and Health Outcomes Among Survivors of COVID-19 Infection 1 Year After Discharge From Hospitals in Wuhan, China.

Importance: The long-term health outcomes and symptom burden of COVID-19 remain largely unclear. Objective: To evaluate health outcomes of COVID-19 survivors 1 year after hospital discharge and to identify associated risk factors. Design, Setting, and Participants: This retrospective, multicenter cohort study was conducted at 2 designated hospitals, Huoshenshan Hospital and Taikang Tongji Hospital, both in Wuhan, China. All adult patients with COVID-19 discharged between February 12 and April 10, 2020, were screened for eligibility. Of a consecutive sample of 3988 discharged patients, 1555 were excluded (796 declined to participate and 759 were unable to be contacted) and the remaining 2433 patients were enrolled. All patients were interviewed via telephone from March 1 to March 20, 2021. Statistical analysis was performed from March 28 to April 18, 2021. Exposures: COVID-19. Main Outcomes and Measures: All patients participated in telephone interviews using a series of questionnaires for evaluation of symptoms, along with a chronic obstructive pulmonary disease (COPD) assessment test (CAT). Logistic regression models were used to evaluate risk factors for fatigue, dyspnea, symptom burden, or higher CAT scores. Results: Of 2433 patients at 1-year follow-up, 1205 (49.5%) were men and 680 (27.9%) were categorized into the severe disease group as defined by the World Health Organization guideline; the median (IQR) age was 60.0 (49.0-68.0) years. In total, 1095 patients (45.0%) reported at least 1 symptom. The most common symptoms included fatigue, sweating, chest tightness, anxiety, and myalgia. Older age (odds ratio [OR], 1.02; 95% CI, 1.01-1.02; P < .001), female sex (OR, 1.27; 95% CI, 1.06-1.52; P = .008), and severe disease during hospital stay (OR, 1.43; 95% CI, 1.18-1.74; P < .001) were associated with higher risks of fatigue. Older age (OR, 1.02; 95% CI, 1.01-1.03; P < .001) and severe disease (OR, 1.51; 95% CI, 1.14-1.99; P = .004) were associated with higher risks of having at least 3 symptoms. The median (IQR) CAT score was 2 (0-4), and a total of 161 patients (6.6%) had a CAT score of at least 10. Severe disease (OR, 1.84; 95% CI, 1.31-2.58; P < .001) and coexisting cerebrovascular diseases (OR, 1.95; 95% CI, 1.07-3.54; P = .03) were independent risk factors for CAT scores of at least 10. Conclusions and Relevance: This study found that patients with COVID-19 with severe disease during hospitalization had more postinfection symptoms and higher CAT scores.

Clinical characteristics and a decision tree model to predict death outcome in severe COVID-19 patients.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) spreads rapidly among people and causes a pandemic. It is of great clinical significance to identify COVID-19 patients with high risk of death. METHODS: A total of 2169 adult COVID-19 patients were enrolled from Wuhan, China, from February 10th to April 15th, 2020. Difference analyses of medical records were performed between severe and non-severe groups, as well as between survivors and non-survivors. In addition, we developed a decision tree model to predict death outcome in severe patients. RESULTS: Of the 2169 COVID-19 patients, the median age was 61 years and male patients accounted for 48%. A total of 646 patients were diagnosed as severe illness, and 75 patients died. An older median age and a higher proportion of male patients were found in severe group or non-survivors compared to their counterparts. Significant differences in clinical characteristics and laboratory examinations were found between severe and non-severe groups, as well as between survivors and non-survivors. A decision tree, including three biomarkers, neutrophil-to-lymphocyte ratio, C-reactive protein and lactic dehydrogenase, was developed to predict death outcome in severe patients. This model performed well both in training and test datasets. The accuracy of this model were 0.98 in both datasets. CONCLUSION: We performed a comprehensive analysis of COVID-19 patients from the outbreak in Wuhan, China, and proposed a simple and clinically operable decision tree to help clinicians rapidly identify COVID-19 patients at high risk of death, to whom priority treatment and intensive care should be given.

Clinical features and death risk factors in COVID-19 patients with cancer: a retrospective study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has spread around the world. This retrospective study aims to analyze the clinical features of COVID-19 patients with cancer and identify death outcome related risk factors. METHODS: From February 10th to April 15th, 2020, 103 COVID-19 patients with cancer were enrolled. Difference analyses were performed between severe and non-severe patients. A propensity score matching (PSM) analysis was performed, including 103 COVID-19 patients with cancer and 206 matched non-cancer COVID-19 patients. Next, we identified death related risk factors and developed a nomogram for predicting the probability. RESULTS: In 103 COVID-19 patients with cancer, the main cancer categories were breast cancer, lung cancer and bladder cancer. Compared to non-severe patients, severe patients had a higher median age, and a higher proportion of smokers, diabetes, heart disease and dyspnea. In addition, most of the laboratory results between two groups were significantly different. PSM analysis found that the proportion of dyspnea was much higher in COVID-19 patients with cancer. The severity incidence in two groups were similar, while a much higher mortality was found in COVID-19 patients with cancer compared to that in COVID-19 patients without cancer (11.7% vs. 4.4%, P = 0.028). Furthermore, we found that neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) were related to death outcome. And a nomogram based on the factors was developed. CONCLUSION: In COVID-19 patients with cancer, the clinical features and laboratory results between severe group and non-severe group were significantly different. NLR and CRP were the risk factors that could predict death outcome.

Atom by Atom Condensation of Sn Single Clusters within Gold-Phosphorus Metal-Inorganic Porous Networks.

Surface supported single-atom catalysts (SACs) and single-cluster catalysts (SCCs) have been an area of rapidly growing interest due to their high efficiency of metal atom utilization and high selectivity and activity toward various catalytic reactions. However, achieving highly dispersed, structurally well-defined SACs and SCCs with high surface loadings while avoiding their sintering to larger nanoparticles (NPs) still remains a nontrivial challenge. Here, by utilizing a recently fabricated porous metal-inorganic gold-phosphorus (AuP) network, highly dispersed single Sn clusters with high surface density can be realized. This is attributed to a synergistic effect of the P6Au6 pores for providing the preferential binding sites to anchor Sn atoms and the role of P9 units as a blocking barrier to prevent the growth of Sn to larger NPs. The atom by atom condensation process of Sn single clusters with sizes ranging from monomers to heptamers as well as their binding configurations with the supporting surface are precisely identified at the atomic level, through the combination of a low-temperature scanning tunneling microscope and density functional theory calculations. Our approach opens new opportunities of utilizing metal-inorganic porous networks for the stabilization of highly dispersed and well-defined SACs and SCCs.

CELSR1 Acts as an Oncogene Regulated by miR-199a-5p in Glioma.

PURPOSE: This study aimed to elucidate the biological function and upstream regulatory mechanism of CELSR1 in glioma. MATERIALS AND METHODS: We evaluated the expression of CELSR1 in glioma by TCGA_GEPIA tool, RT-qPCR, and Western blot assays. CCK-8, wound healing, and transwell invasion assays were, respectively, performed to detect the effect of CELSR1 on cell proliferation, migration, and invasion. The upstream regulatory miRNAs of CELSR1 were predicted by TargetScan and validated by luciferase activity reporter assay. RESULTS: CELSR1 is overexpressed in glioma (P<0.05). CELSR1 promoted glioma cell proliferation, migration and invasion (P<0.01). CELSR1 was a direct target of miR-199a-5p. miR199a-5p mimics significantly inhibited CELSR1 mRNA and protein expression (P<0.01). miR199a-5p mimics reversed the effects of CELSR1 on glioma cell behaviors (P<0.01). CONCLUSION: CELSR1 acts as an oncogene promoting glioma cell proliferation, migration, and invasion, which is regulated by miR199a-5p.

Designing Kagome Lattice from Potassium Atoms on Phosphorus-Gold Surface Alloy.

Materials with flat bands are considered as ideal platforms to explore strongly correlated physics such as the fractional quantum hall effect, high-temperature superconductivity, and more. In theory, a Kagome lattice with only nearest-neighbor hopping can give rise to a flat band. However, the successful fabrication of Kagome lattices is still very limited. Here, we provide a new design principle to construct the Kagome lattice by trapping atoms into Kagome arrays of potential valleys, which can be realized on a potassium-decorated phosphorus-gold surface alloy. Theoretical calculations show that the flat band is less correlated with the neighboring trivial electronic bands, which can be further isolated and dominate around the Fermi energy with increased Kagome lattice parameters of potassium atoms. Our results provide a new strategy for constructing Kagome lattices, which serve as an ideal platform to study topological and more general flat band phenomena.

Synthesis of Monolayer Blue Phosphorus Enabled by Silicon Intercalation.

The growth of entirely synthetic two-dimensional (2D) materials could further expand the library of naturally occurring layered solids and provide opportunities to design materials with finely tunable properties. Among them, the synthesis of elemental 2D materials is of particular interest as they represent the chemically simplest case and serve as a model system for exploring the on-surface synthesis mechanism. Here, a pure atomically thin blue phosphorus (BlueP) monolayer is synthesized via silicon intercalation of the BlueP-Au alloy on Au(111). The intercalation process is characterized at the atomic scale by low-temperature scanning probe microscopy and further corroborated by synchrotron radiation-based X-ray photoelectron spectroscopy measurements. The evolution of the band structures from the BlueP-Au alloy into Si-intercalated BlueP are clearly revealed by angle-resolved photoemission spectroscopy and further verified by density functional theory calculations.

Study of the SCL-90 Scale and Changes in the Chinese Norms.

Objective: This study aimed to investigate the Chinese norms for the Symptom Checklist 90 (SCL-90) scale and its application. Methods: In total, 7,489 adults from Tianjin and Qingdao in China were included. Their data were compared with the norm data of 1,388 people published by Jin et al., the combined norms published by Tang et al., the data of 2,808 adults published by Chen and Li, and the data of 1,890 adults from Tong in China. Results: In five different periods, notable changes were observed in each factor of the SCL-90 that significantly differed from the previous norms. The scores of each factor showed an increasing annual trend. Compulsion consistently obtained the highest scores, and phobia consistently obtained the lowest scores. The scores tended to decrease from compulsion to anxiety, and psychosis scored lower than paranoia. There was a significant difference in the detection rate between the critical screening value of two points and the standard score. Using the standard score as the critical value, the detection rate ranged between 13 and 16% and was relatively concentrated. Using two points as the critical value, the detection rate ranged between 38 and 50%. Conclusion: The usual model in China is not consistent with social development. Using two points as the critical value is no longer suitable for the SCL-90. New Chinese norms and measurement standards should be developed. The mean value plus one standard deviation could be used as the new measurement standard.

Reversible Oxidation of Blue Phosphorus Monolayer on Au(111).

Practical applications of two-dimensional (2D) black phosphorus (BP) are limited by its fast degradation under ambient conditions, for which many different mechanisms have been proposed; however, an atomic level understanding of the degradation process is still hindered by the absence of bottom-up methods for the growth of large-scale few-layer black phosphorus. Recent experimental success in the fabrication of single-layer blue phosphorus provides a model system to probe the oxidation mechanism of two-dimensional (2D) phosphorene down to single-layer thicknesses. Here, we report an atomic-scale investigation of the interaction between molecular oxygen and blue phosphorus. The atomic structure of blue phosphorus and the local binding sites of oxygen have been precisely identified using qPlus-based noncontact atomic force microscopy. A combination of low-temperature scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements reveal a thermally reversible oxidation process of blue phosphorus in a pure oxygen atmosphere. Our study clearly demonstrates the essential role of oxygen in the initial oxidation process, and it sheds further light on the fundamental pathways of the degradation mechanism.

Pt Single Atoms Embedded in the Surface of Ni Nanocrystals as Highly Active Catalysts for Selective Hydrogenation of Nitro Compounds.

Single-atom catalysts exhibit high selectivity in hydrogenation due to their isolated active sites, which ensure uniform adsorption configurations of substrate molecules. Compared with the achievement in catalytic selectivity, there is still a long way to go in exploiting the catalytic activity of single-atom catalysts. Herein, we developed highly active and selective catalysts in selective hydrogenation by embedding Pt single atoms in the surface of Ni nanocrystals (denoted as Pt1/Ni nanocrystals). During the hydrogenation of 3-nitrostyrene, the TOF numbers based on surface Pt atoms of Pt1/Ni nanocrystals reached ∼1800 h-1 under 3 atm of H2 at 40 °C, much higher than that of Pt single atoms supported on active carbon, TiO2, SiO2, and ZSM-5. Mechanistic studies reveal that the remarkable activity of Pt1/Ni nanocrystals derived from sufficient hydrogen supply because of spontaneous dissociation of H2 on both Pt and Ni atoms as well as facile diffusion of H atoms on Pt1/Ni nanocrystals. Moreover, the ensemble composed of the Pt single atom and nearby Ni atoms in Pt1/Ni nanocrystals leads to the adsorption configuration of 3-nitrostyrene favorable for the activation of nitro groups, accounting for the high selectivity for 3-vinylaniline.

Obtaining Intrinsically Occupied Free-Space Superatom States in an Encapsulated Ca2N Nanotube.

By considering a group of atoms as a whole, the superatom state concept has been proposed to understand complex chemical systems. Superatom states distributed in free space are important in determining the interactions between superatoms and also the reactions of a superatom system with other external molecules. Unfortunately, all free-space superatom states reported to date are unoccupied states, which strongly limit their applications. In this study, we predict that both occupied and unoccupied free-space superatom states exist in an encapsulated Ca2N nanotube. In this composite system, the inner Ca2N nanotube provides anionic electrons in free space inside the tube, which form occupied s-, p-, and d-like superatom states. The outer carbon nanotube layer provides an effective protection for these free-space superatom states from the ambient environment. Such protected superatom states with flexible occupation statuses are expected to have a great potential in various application fields including catalysis and electronics.

Growth of Quasi-Free-Standing Single-Layer Blue Phosphorus on Tellurium Monolayer Functionalized Au(111).

Blue phosphorus, a newly proposed allotrope of phosphorus, represents a promising 2D material with predicted large tunable band gap and high charge-carrier mobility. Here, we report a simple method for the growth of quasi-free-standing single layer blue phosphorus on tellurium functionalized Au(111) by using black phosphorus as the precursor. In situ low-temperature scanning tunneling microscopy (LT-STM) measurements were used to monitor the growth of the single-layer blue phosphorus, which forms triangular structures arranged hexagonally on the tellurium layer. As revealed by in situ X-ray photoelectron spectroscopy, LT-STM measurements, and density functional theory calculation, the blue phosphorus layer weakly interacts with the underlying tellurium layer.

Precursor Triggering Synthesis of Self-Coupled Sulfide Polymorphs with Enhanced Photoelectrochemical Properties.

Heteronanostructures have attracted intensive attention due to their electronic coupling effects between distinct components. Despite tremendous advances of nanostructure fabrication, combining independent polymorphs by forming heterojunction is still challenging but fascinating, such as copper sulfides (Cu2-xS), exhibiting varying band gaps and crystal structures with various stoichiometries. Herein, self-coupled Cu2-xS polymorphs (Cu1.94S-CuS) by a facile one-pot chemical transformation route have been reported for the first time. Unprecedentedly, a manganous precursor plays a crucial role in inducing and directing the formation of such a dumbbell-like architecture, which combines 1D Cu1.94S with 2D CuS. During the transformation, Mn2+ ions mediate the Cu+ ions diffusion and phase conversion process particularly. Furthermore, this self-coupled polymorphic structure exhibits significantly enhanced photoelectrochemical properties compared with the individual Cu1.94S nanocrystals and CuS nanoplates, originating from the unique heterointerfaces constructed by intrinsic band alignment and the enhanced contact between high conductivity hexagonal planes and the working electrode revealed by density functional theory (DFT) calculations. So we anticipate this emerging interfacial charge separation could provide useful hints for applications in optoelectronic devices or photocatalysis.

Epitaxial Growth of Single Layer Blue Phosphorus: A New Phase of Two-Dimensional Phosphorus.

Blue phosphorus, a previously unknown phase of phosphorus, has been recently predicted by theoretical calculations and shares its layered structure and high stability with black phosphorus, a rapidly rising two-dimensional material. Here, we report a molecular beam epitaxial growth of single layer blue phosphorus on Au(111) by using black phosphorus as precursor, through the combination of in situ low temperature scanning tunneling microscopy and density functional theory calculation. The structure of the as-grown single layer blue phosphorus on Au(111) is explained with a (4 × 4) blue phosphorus unit cell coinciding with a (5 × 5) Au(111) unit cell, and this is verified by the theoretical calculations. The electronic bandgap of single layer blue phosphorus on Au(111) is determined to be 1.10 eV by scanning tunneling spectroscopy measurement. The realization of epitaxial growth of large-scale and high quality atomic-layered blue phosphorus can enable the rapid development of novel electronic and optoelectronic devices based on this emerging two-dimensional material.

Ratio-controlled synthesis of CuNi octahedra and nanocubes with enhanced catalytic activity.

Non-noble bimetallic nanocrystals (NCs) have been widely explored due to not only their low cost and abundant content in the Earth's crust but also their outstanding performance in catalytic reactions. However, controllable synthesis of non-noble alloys remains a significant challenge. Here we report a facile synthesis of CuNi octahedra and nanocubes with controllable shapes and tunable compositions. Its success relies on the use of borane morpholine as a reducing agent, which upon decomposition generates a burst of H2 molecules to induce rapid formation of the nuclei. Specifically, octahedra switched to nanocubes with an increased amount of borane morpholine. In addition, the ratio of CuNi NCs could be facilely tuned by changing the molar ratio of both precursors. The obtained CuNi NCs exhibited high activity in aldehyde-alkyne-amine coupling reactions, and their performance is strongly facet- and composition-dependent due to the competition of the surface energy (enhanced by increasing the percent of Ni) and active sites (derived from Cu atoms).

Aerobic Oxidation of Cyclohexane on Catalysts Based on Twinned and Single-Crystal Au75Pd25 Bimetallic Nanocrystals.

Bimetallic Au75Pd25 nanocrystals with shapes of icosahedron and octahedron were synthesized by adding different amounts of iodide ions, and were employed as catalysts for solvent-free aerobic oxidation of cyclohexane. Although both icosahedrons and octahedrons were bounded by {111} facets, the turnover frequency number of Au75Pd25 icosahedrons reached 15,106 h(-1), almost three times as high as that of Au75Pd25 octahedrons. The conversion of cyclohexane reached 28.1% after 48 h using Au75Pd25 icosahedrons, with the selectivity of 84.3% to cyclohexanone. Density functional theory calculations along with X-ray photoelectron spectroscopy examinations reveal that the excellent catalytic performance of AuPd icosahedrons could be ascribed to twin-induced strain and highly negative charge density of Au atoms on the surface.

Obtaining two-dimensional electron gas in free space without resorting to electron doping: an electride based design.

Nearly free electron (NFE) states are widely existed on atomically smooth surfaces in two-dimensional materials. Since they are mainly distributed in free space, these states can in principle provide ideal electron transport channels without nuclear scattering. Unfortunately, NFE states are typically unoccupied, and electron doping is required to shift them toward the Fermi level and, thus, to be involved in electron transport. Instead of occupying these NFE states, it is more desirable to have intrinsic nucleus-free two-dimensional electron gas in free space (2DEG-FS) at the Fermi level without relying on doping. Inspired by a recently identified electride material, we suggest that Ca2N monolayer should possess such a 2DEG-FS state, which is then confirmed by our first-principles calculations. Phonon dispersion in Ca2N monolayer shows no imagery frequency indicating that the monolayer structure is stable. A mechanical analysis demonstrates that Ca2N bulk exfoliation is feasible to produce a freestanding monolayer. However, in real applications, the strong chemical activity of 2DEG-FS may become a practical issue. It is found that some ambient molecules can dissociatively adsorb on the Ca2N monolayer, accompanying with a significant charge transfer from the 2DEG-FS state to adsorbates. To protect the 2DEG-FS state from molecule adsorption, we predict that graphane can be used as an effective encapsulating material. A well-encapsulated intrinsic 2DEG-FS state is expected to play an important role in low-dimensional electronics by realizing nuclear scattering free transport.

Case report: Acute renal injury as a result of liposomal amphotericin B treatment in sodium stibogluconate unresponsive visceral leishmaniasis.

We report an unusual case of visceral leishmaniasis occurring in a patient from Sichuan China. The patient presented with a remitting fever, anemia, and pancytopenia. The case was confirmed as visceral leishmaniasis by microscopical detection of the Leishmania species amastigote in bone marrow aspirate. The patient was treated with 10 mg/kg/day of sodium stibogluconate for 5 days, with no therapeutic response. As a result, the patient was treated with liposomal amphotericin B (LAB) at 10 mg/day as an initial dosage. After treatment with an increasing drug dosage for 7 days, acute renal injury was evident as indicated by increased serum creatinine and urea nitrogen. LAB administration was discontinued until serum creatinine and serum urea nitrogen regressed on Day 15. Two maintenance treatments of 100 mg/day LAB were given on Days 19 and 26 (total 870 mg, 14.5 mg/kg). Bone marrow aspirate and clinical examination suggested total remission.

Intrahepatic PD-1/PD-L1 up-regulation closely correlates with inflammation and virus replication in patients with chronic HBV infection.

Chronic hepatitis B was characterized by fluctuant immune response to infected hepatocytes resulting in hepatic inflammation and virus persistence. Recently, Programmed Death-1 (PD-1) and its ligand PD-L1 have been demonstrated to play an essential role in balancing antiviral immunity and inflammation in the livers of acute hepatitis B patients, significantly influencing disease outcome. PD-1 up-regulation in peripheral T cells is associated with immune dysfunction in chronic hepatitis B patients. However, the effect of PD-1/PD-L1 on hepatic damage and chronic infective status is still unknown in patients with chronic HBV infection. Here, we report up-regulation of PD-1 and PD-L1 in liver biopsies from 32 chronic HBV patients compared to 4 healthy donors. PD-1/PD-L1 up-regulation was significantly associated with hepatic inflammation and ALT elevation. Moreover, appropriate up-regulation but not overexpression of PD-L1 in the active phase of chronic hepatitis B as well as lower expression of PD-L1 in the inactive phase in liver residential antigen presenting cells (including Kupffer cells and sinusoidal endothelial cells) may contribute to viral inhibition. Our data suggest that the intrahepatic interaction of PD-1 and PD-L1 might play an important role in balancing the immune response to HBV and immune-mediated liver damage in chronic HBV infection.