[Effect of Staphylococcal Nuclease and Tudor Domain Containing 1/SLC7A11 on the Occurrence and Development of Osteosarcoma by Inhibiting Ferroptosis].

Objective To investigate the effect of staphylococcal nuclease and tudor domain containing 1(SND1) on the biological function of osteosarcoma cells and decipher the mechanism of SND1 in regulating ferroptosis in osteosarcoma cells via SLC7A11. Methods Human osteoblasts hFOB1.19 and osteosarcoma cell lines Saos-2,U2OS,HOS,and 143B were cultured,in which the expression level of SND1 was determined.Small interfering RNA was employed to knock down the expression of SND1(si-SND1) in the osteosarcoma cell line HOS and 143B.The CCK8 assay kit,colony formation assay,and Transwell assay were employed to examine the effect of SND1 expression on the biological function of osteosarcoma cells.Furthermore,we altered the expression of SND1 and SLC7A11 in osteosarcoma cells to investigate the effect of SND1 on osteosarcoma ferroptosis via SLC7A11. Results The mRNA and protein levels of SND1 in Saos-2,U2OS,HOS,and 143B cells were higher than those in hFOB1.19 cells(all P<0.01).Compared with the control group,transfection with si-SND1 down-regulated the expression level of SND1 in HOS and 143B cells(all P<0.01),decreased the viability of HOS and 143B cells,reduced the number of colony formation,and inhibited cell invasion and migration(all P<0.001).The ferroptosis inducer Erastin promoted the apoptosis of HOS and 143B cells,while the ferroptosis inhibitor Ferrostatin-1 improved the viability of HOS and 143B cells(all P<0.001).After SND-1 knockdown,Erastin reduced the viability of HOS and 143B cells,while Ferrostatin-1 restored the cell viability(all P<0.001).After treatment with Erastin in the si-SND1 group,the levels of iron and malondialdehyde were elevated,and the level of glutathione was lowered(all P<0.001).The results of in vivo experiments showed that SND1 knockdown inhibited the mass of the transplanted tumor in 143B tumor-bearing nude mice(P<0.001).Knocking down the expression of SND1 resulted in down-regulated SLC7A11 expression(all P<0.001) and increased ferroptosis in HOS and 143B cells(P<0.001,P=0.020). Conclusions SND1 presents up-regulated expression in osteosarcoma cells.It may inhibit ferroptosis by up-regulating the expression of SLC7A11,thereby improving the viability of osteosarcoma cells.

NRT1.2 overexpression enhances the synergistic interplay between ABA-generating bacteria and biochars in reducing heavy metal accumulation in pak choi.

The agricultural sector faces severe challenges owing to heavy metal (HM) contamination of farmlands, requiring urgent preventive measures. To address this, we investigated the impact of the synergistic application of Azospirillum brasilense, a growth-promoting rhizobacterium producing abscisic acid (ABA), and biochar to minimize HM accumulation in pak choi, using three distinct expression levels of the ABA transporter NRT1.2 in pak choi and three different types of contaminated soils as experimental materials. The results revealed that pak choi with low, medium, and high NRT1.2 expression intensity, when subjected to bacterial strain-biochar treatment, exhibited an increasing trend in ABA content compared to the control. Correspondingly, the aboveground HM content decreased by 1-49 %, 22-52 %, and 15-96 %, whereas the fresh weight increased by 12-38 %, 88-126 %, and 152-340 %, respectively, showing a significant correlation with NRT1.2 expression. Pearson correlation analysis demonstrated that NRT1.2 expression intensity was inversely associated with the combined treatment's reduction in HM accumulation and positively correlated with the promotional effect. Simultaneously, soil discrepancies significantly affected the combined treatment, which was likely associated with variations in the active forms of HM in each soil. Consequently, when employing ABA-producing bacteria for mitigating crop HM accumulation, selecting plants with higher relative NRT1.2 expression intensity, combined with biochar, is recommended.

Comparison of nerve versus tendon transfer for radial nerve palsy.

OBJECTIVE: This study aims to investigate the choice of intervention time and operation mode between nerve and tendon transfer for the treatment of radial nerve palsy (RNP). METHODS: 46 RNP patients underwent nerve transfer (n = 22) and tendon transfer (n = 24). The intraoperative blood loss, main incision length, operation duration, and length of hospital stay and follow-up period of patients in these two groups were recorded and compared. The range of motion (ROM) of the elbow, wrist, fingers, and thumb, the hand grip and pinch strength, the Disabilities of Arm, Shoulder, and Hand (DASH) and the 36-Item Short Form Health Survey (SF-36) scores were measured and compared preoperatively and postoperatively between the two groups. RESULTS: The ROM of thumb and the hand grip strength of patients in the nerve transfer group were greater than that in the tendon transfer (P < 0.05). Both of the two groups indicated significant improvements in the ROM of elbow, wrist, finger, thumb and the hand grip and pinch strength (P < 0.05) postoperatively. The DASH scores decreased significantly at 6 months (P < 0.05) and 12 months (P < 0.05) after surgery in both groups, while the postoperative SF-36 scores significantly increased (P < 0.05). There was no significant difference in postoperative DASH and SF-36 scores between the two groups (P > 0.05). CONCLUSION: In summary, both nerve and tendon transfer techniques are effective treatments for RNP. Nerve transfer is particularly advantageous for early RNP, while tendon transfer is suitable for patients with radial nerve injury more than one year.

[Characterization of Cell Subsets Associated With Prognosis of Osteosarcoma Based on Single-Cell Sequencing Data].

Objective To explore the cell subsets and characteristics related to the prognosis of osteosarcoma by analyzing the cellular composition of tumor tissue samples from different osteosarcoma patients.Methods The single-cell sequencing data and bulk sequencing data of different osteosarcoma patients were downloaded.We extracted the information of cell samples for dimensionality reduction,annotation,and cell function analysis,so as to identify the cell subsets and clarify the cell characteristics related to the prognosis of osteosarcoma.The development trajectory of macrophages with prognostic significance was analyzed,and the prognostic model of osteosarcoma was established based on the differentially expressed genes of macrophage differentiation.Results The cellular composition presented heterogeneity in the patients with osteosarcoma.The infiltration of mononuclear phagocytes in osteosarcoma had prognostic significance(P=0.003).Four macrophage subsets were associated with prognosis,and their signature transcription factors included RUNX3(+),ETS1(+),HOXD11(+),ZNF281(+),and PRRX1(+).Prog_Macro2 and Prog_Macro4 were located at the end of the developmental trajectory,and the prognostic ability of macrophage subsets increased with the progression of osteosarcoma.The prognostic model established based on the differentially expressed genes involved in macrophage differentiation can distinguish the survival rate of osteosarcoma patients with different risks(P<0.001).Conclusion Macrophage subsets are closely related to the prognosis of osteosarcoma and can be used as the key target cells for the immunotherapy of osteosarcoma.

A promising product: Abscisic acid-producing bacterial agents for restricting cadmium enrichment in field vegetable crops.

Soil heavy metal contamination and its enrichment in the edible parts of crops have gained global concern. In this study, a compound bacterial agent possessing the ability to produce the plant hormone, abscisic acid (ABA), was applied to contaminated farmland in Hunan province. Its application reduced the concentration of Cd in radish, cabbage, mustard, and lettuce by 15-144%. Accordingly, the Cd contents in these vegetables were found to be below the maximum limits set by GB 2762-2017. Meanwhile, bacteria agents also led to a significant increase in crops yield by 45-82%. Furthermore, the nutritional indices, including soluble sugar and soluble protein increased by 18-66%, as well as the antioxidant indices, including total phenolic, ascorbate content, and DPPH capacity, enhanced by 12-76%, 10-49% and 50-140%, respectively. In conclusion, the use of ABA-producing bacteria is anticipated to be a novel approach for the safe use of soil with moderate and low pollution.

LncRNA EBLN3P Facilitates Osteosarcoma Metastasis by Enhancing Annexin A3 mRNA Stability and Recruiting HuR.

BACKGROUND: Osteosarcoma (OS) represents a common type of bone cancer. Long non-coding RNAs (LncRNAs) have shown their potential in therapeutic modalities for OS. This study's purpose was to reveal the action of lncRNA EBLN3P on OS growth and metastasis and its mechanism. METHODS: Expressions of EBLN3P/Hu antigen R (HuR)/Annexin A3 (ANXA3) were determined by RT-qPCR/Western blot. Proliferation/migration/invasion of OS cells were assessed via CCK-8/Transwell assays after interfering EBLN3P/ANXA3/HuR. The co-localization of EBLN3P/ANXA3/HuR cells was observed by FISH/immunofluorescence assays. Interplays among EBLN3P/ANXA3/HuR and the half-life period of ANXA3 were assessed by RNA immunoprecipitation/RNA pull-down/RNA stability experiment. The nude mouse xenograft model was established, followed by EBLN3P treatment to assess the function of EBLN3P on OS. RESULTS: EBLN3P/ANXA3 was highly expressed in OS cells. Silencing EBLN3P or ANXA3 limited the proliferation/migration/invasion of OS cells. Mechanically, EBLN3P/ANXA3 can bind to HuR, and EBLN3P enhanced ANXA3 mRNA stability by recruiting HuR, thus facilitating OS cell growth. Upregulated HuR or ANXA3 counteracted the suppressive action of silencing EBLN3P on OS cells. In vivo experiments revealed facilitated tumor growth and metastasis in vivo fomented by EBLN3P through manipulation of HuR/ANXA3. CONCLUSIONS: EBLN3P enhanced proliferative/migrative/invasive potentials of OS cells via increasing ANXA3 mRNA stability and protein level by recruiting HuR, which provided new potential therapeutic targets for OS clinical treatment. EBLN3P and ANXA3 might have potential roles in OS diagnosis, treatment, and prognosis. This study provided a theoretical reference for further clinical research in tumor surgery.

Forecast for peak infections in the second wave of the Omicron after the adjustment of zero-COVID policy in the mainland of China.

On December 7, 2022, the Chinese government optimized the current epidemic prevention and control policy, and no longer adopted the zero-COVID policy and mandatory quarantine measures. Based on the above policy changes, this paper establishes a compartment dynamics model considering age distribution, home isolation and vaccinations. Parameter estimation was performed using improved least squares and Nelder-Mead simplex algorithms combined with modified case data. Then, using the estimated parameter values to predict a second wave of the outbreak, the peak of severe cases will reach on 8 May 2023, the number of severe cases will reach 206,000. Next, it is proposed that with the extension of the effective time of antibodies obtained after infection, the peak of severe cases in the second wave of the epidemic will be delayed, and the final scale of the disease will be reduced. When the effectiveness of antibodies is 6 months, the severe cases of the second wave will peak on July 5, 2023, the number of severe cases is 194,000. Finally, the importance of vaccination rates is demonstrated, when the vaccination rate of susceptible people under 60 years old reaches 98%, and the vaccination rate of susceptible people over 60 years old reaches 96%, the peak of severe cases in the second wave of the epidemic will be reached on 13 July 2023, when the number of severe cases is 166,000.

Organic fertilizer and irrigation water are the primary sources of microplastics in the facility soil, Beijing.

The large-scale utilization of plastic products in agricultural facility production has resulted in considerable accumulation of microplastics in the soil. However, there is a lack of systematic research on the accumulation and distribution of microplastics in facility agriculture. This study examined the presence of microplastics in the 15 representatives of Beijing facility agriculture soil in five districts with different planting years, and assessed the potential pollution risks. The abundance of microplastics in soil layers at a depth of 0-10, 10-20, and 20-30 cm was 896.5 ± 80.0 (range, 160-2120), 630.6 ± 47.0 (180-1340), and 445.3 ± 47.0 (80-1480) items/kg, respectively. Overall, the microplastics were primarily fiber-shaped (72.2 %), white (75.9 %), 1-2 mm in size (37.9 %), and composed of polypropylene and polyethene. The risk assessment indices of the microplastics in the 0-10, 10-20, and 20-30 cm soil layers were 272.1, 289.5, and 291.6, respectively, representing a risk level of 4 in each case. Using the conditional fragmentation model, we found that the microplastics in facility soil featured low stability and small sizes, and their primary sources were organic fertilizer and irrigation water. The number of mulching years, irrigation method, and the amount of organic fertilizer applied, influenced the accumulation of microplastics in the facility soil. This study provides scientific evidence supporting the pollution levels and need for risk control related to microplastics in facility soils.

Synergistic interplay between ABA-generating bacteria and biochar in the reduction of heavy metal accumulation in radish, pakchoi, and tomato.

Heavy metal (HM) contamination is an environmental concern that threatens the agricultural product safety and human health. To address this concern, we developed a novel strategy involving the synergistic application of Azospirillum brasilense, a growth-promoting rhizobacterium which produces abscisic acid (ABA), and biochar to minimize HM accumulation in the edible parts of vegetable crops. Compared to A. brasilense or biochar alone, the concentrations of Cd, Ni, Pb, and Zn in radish (Raphanus sativus L.), pakchoi (Brassica chinensis L.), and tomato (Lycopersicon esculentum L.) decreased by 18-63% and 14-56%, respectively. Additionally, the synergistic treatment led to a 14-63% decrease in the bioconcentration factor. The biomass of the edible parts of the three crops increased by 65-278% after synergistic treatment, surpassing the effects of single treatments. Furthermore, the synergistic application enhanced the SPAD values by 1-45% compared to single treatments. The MDA concentrations in stressed plants decreased by 16-39% with the bacteria-biochar co-treatment compared to single treatments. Co-treatment also resulted in increased soluble protein and sugar concentrations by 8-174%, and improvements in flavonoids, total phenols, ascorbic acid, and DPPH levels by 2-50%. Pearson correlation analysis and structural equation modeling revealed that the synergistic effect was attributed to the enhanced growth of A. brasilense facilitated by biochar and the improved availability of HMs in soils. Notably, although ABA concentrations were not as high as those achieved with A. brasilense alone, they were maintained at relatively high levels. Overall, the synergistic application of A. brasilense-biochar might have remarkable potential for reducing the accumulation of HMs while promoting growth and improving nutritional and antioxidant qualities in tuberous, leafy, and fruit crops.

Tough Structural Adhesives with Ultra-Resistance to Both High and Cryogenic Temperature.

Structural adhesion at high temperature has been a challenge for organic adhesives, and the commercially available adhesives that can work at a temperature above 150 °C is rather limited. Herein, two novel polymers were designed and synthesized via facile strategy, which involves polymerization between melamine (M) and M-Xylylenediamine (X), as well as copolymerization of MX and urea (U). With well-balanced rigid-flexible structures, the obtained MX and MXU resins were proved to be outstanding structural adhesives at a wide range temperature of -196~200 °C. They provided room-temperature bonding strength of 13~27 MPa for various substrates, steel bonding strength of 17~18 MPa at cryogenic temperature (-196 °C), and 15~17 MPa at 150 °C. Remarkably, high bonding strength of 10~11 MPa was retained even at 200 °C. Such superior performances were attributed to a high content of aromatic units, which leads to high glass transition temperature (Tg) up to ~179 °C, as well as the structural flexibility endowed by the dispersed rotatable methylene linkages.

K-line tilt as a novel potential risk factor for cervical Modic change: a retrospective study.

BACKGROUND: Cervical sagittal parameters are important parameters that reflect the mechanical stress in the sagittal plane of the cervical spine and are an important basis for predicting the clinical status and prognosis of patients. Although it has been confirmed that there is a significant correlation between cervical Modic changes and some sagittal parameters. However, as a newly discovered sagittal parameter, there is no report on the relationship between the K-line tilt and the Modic changes of cervical spine. METHODS: A retrospective analysis was performed for 240 patients who underwent cervical magnetic resonance imaging scan for neck and shoulder pain. Among them, 120 patients with Modic changes, namely the MC(+) group, were evenly divided into three subgroups of 40 patients in each group according to different subtypes, namely MCI subgroup, MCII subgroup and MCIII subgroup. One hundred twenty patients without Modic changes were included in MC(-) group. We measured and compared the sagittal parameters of cervical spine among different groups, including K-line tilt, C2-C7 sagittal axial vertical distance (C2-C7 SVA), T1 slope and C2-7 lordosis. Logistic regression was used to analyse the risk factors of cervical Modic changes. RESULTS: The K-line tilt and C2-7 lordosis were significantly different between MC(+) group and MC(-) group (P < 0.05). The K-line tilt greater than 6.72° is a risk factor for Modic changes in cervical spine (P < 0.05). At the same time, the receiver operating characteristic curve showed that this change had moderate diagnostic value when the area under the curve was 0.77. CONCLUSION: This study shows that the K-line tilt greater than 6.72° is a potential risk factor for Modic changes in cervical spine. When the K-line tilt is greater than 6.72°, we should be alert to the occurrence of Modic changes. TRIAL REGISTRATION NUMBER: 2022ER023-1.

ROS-Triggered Self-Assembled Nanoparticles Based on a Chemo-Sonodynamic Combinational Therapy Strategy for the Noninvasive Elimination of Hypoxic Tumors.

The hypopermeability and hypoxia in the tumor milieu are important factors that limit multiple treatments. Herein, the reactive oxygen species (ROS)-triggered self-assembled nanoparticles (RP-NPs) was constructed. The natural small molecule Rhein (Rh) was encapsulated into RP-NPs as a sonosensitizer highly accumulated at the tumor site. Then highly tissue-permeable ultrasound (US) irradiation induced apoptosis of tumor cells through the excitation of Rh and acoustic cavitation, which prompted the rapid production of large amounts of ROS in the hypoxic tumor microenvironment. In addition, the thioketal bond structures in the innovatively designed prodrug LA-GEM were triggered and broken by ROS to achieve rapid targeted release of the gemcitabine (GEM). Sonodynamic therapy (SDT) increased the tissue permeability of solid tumors and actively disrupted redox homeostasis via mitochondrial pathways to kill hypoxic tumor cells, and the triggered response mechanism to GEM synergistically amplified the effect of chemotherapy. The chemo-sonodynamic combinational treatment approach is highly effective and noninvasive, with promising applications for hypoxic tumor elimination, such as in cervical cancer (CCa) patients who want to maintain their reproductive function.

Hydrodynamic Kelvin-Helmholtz instability on metallic surface.

Kelvin-Helmholtz instability on metallic surface is relevant to intense oblique impact in many physical processes such as explosive welding, Inertial Confinement Fusion and planetary impact events. Evolution of instability results in the formation of wavy morphology leading to material bonding or even mixing. However, mostly due to lack method to describe the dynamic behavior, instability mechanism controlled by elastoplastic properties of metal remains elusive. Here, we introduce a theory to reveal the evolution characteristics aroused by tangential velocity. Our simulations find that the unstable metallic surfaces exhibit amplitude growth and tangential motion by overcoming the depression of yield strength to generate wavy morphology. For diverse loading velocities, corrugated surfaces and material properties, an instability boundary distinguishes all unstable evolutions. Our analytical method with scale-independent variables reproducing numerical findings reveals plentiful characteristics of instability in strength materials. For designed loading velocities and material in oblique impact experiment in laboratory, the property of corrugated surfaces becomes an important factor to determine instability evolution.

Endowing Covalent Organic Frameworks with Photoresponsive Active Sites for Controllable Propylene Adsorption.

Photoresponsive covalent organic frameworks (PCOFs) have emerged as attractive candidates for adsorption, but it is challenging to construct PCOF adsorbents due to structural order loss of covalent organic frameworks (COFs) after introducing photoresponsive motifs and/or tedious steps of postmodification. Here, a facile strategy is developed, by dispersing photoresponsive metal-organic polyhedra (PMOP) into COFs, to endow COFs with photoresponsive adsorption sites. As a proof-of-concept study, a COF with pore size of 4.5 nm and PMOP with suitable molecular size (4.0 and 3.1 nm for trans and cis configuration, respectively) are selected to meet the requirements of proper accommodation space, good guest dispersion, and free isomerization. The structure of COF is well preserved after introducing PMOPs. Interestingly, the obtained photoresponsive host-guest composite (PHGC) adsorbents exhibit photomodulated adsorption capacity on propylene (C3 H6 ) and the change in adsorption capacity can reach up to 43.3% and is stable during multiple cycles. Density functional theory calculations reveal that visible-light irradiation drives the azobenzene motifs in PHGCs to the trans configuration and the adsorption sites are fully open and interact with C3 H6 . UV-light irradiation makes the azobenzene motifs transform to the cis configuration, leading to the shield of the adsorption sites and the consequent release of C3 H6 .

Chitosan-tannin adhesive: Fully biomass, synthesis-free and high performance for bamboo-based composite bonding.

Inspired by phenol-amine chemistry of mussels, a synthesis-free and fully biomass adhesive composed of chitosan and tannin (CST) was successfully developed by a facile method. The performance of CST adhesive for bonding bamboo, wood and bamboo-wood substrates were tested. When 160 °C hot-press temperature was used, dry lap shear strength above 5.00 MPa was obtained. The CST adhesive has remarkable water resistance and low cure temperature as high wet shear strength of 2.37 MPa for plybamboo specimens was achieved after 3 h boiling in water even though low hot-press temperature of 100 °C was applied. Further, high strength of 1.78 MPa remained after 72 h boiling. With higher hot-press temperatures used, wet shear strength above 3.60 MPa was achieved. The adhesion performance for wood substrate was also superior to other phenol-amine adhesives reported in literatures. The bamboo-wood composites assembled with CST adhesive show excellent mechanical performance, specifically modulus of rupture (MOR) of 100-133 MPa and modulus of elasticity (MOE) of 10-13 GPa were achieved with different hot-press temperatures used. Given the advantages including outstanding water resistance, facile preparation, fully biomass, and low cure temperature, CST adhesive exhibited great potential to be an ideal alternative to formaldehyde-based resin for wood and bamboo bonding.

Quantitative evaluation of the role of Fangcang shelter hospitals in the control of Omicron transmission: A case study of the outbreak in Shanghai, China in 2022.

Since Omicron began to spread in China, Shanghai has become one of the cities with more severe outbreaks. Under the comprehensive consideration of the vaccine coverage rate, the number of Fangcang shelter hospital beds and the number of designated hospital beds in Shanghai, this paper established a deterministic compartmental model and used the Nelder-Mead Simplex Direct Search Algorithm and chi-square values to estimate the model parameters. we calculate ℛ0 = 3.6429 when the number of beds in the Fangcang shelter hospital is relatively tight in the second stage and ℛ0 = 0.4974 in the fifth stage when there are enough beds in both Fangcang shelter hospital and designated hospital. Then we perform a sensitivity analysis on ℛ0 by using perturbation of fixed point estimation of model parameters in the fifth stage, and obtain three parameters that are more sensitive to ℛ0, which are transmission rate (ß 1d ), proportion of the infectious (η) and the hospitalization rate of asymptomatic infected cases (δ 1). Through simulation, we obtain that if the hospitalization rate of asymptomatic infections δ 2 > 0.9373 or the transmission rate ß 1b  < 0.0467, the second stage of Omicron transmission in Shanghai can be well controlled. Finally, we find the measure that converting the National Convention and Exhibition Center (NECC) into a Fangcang shelter hospital has played an important role in curbing the epidemic. Whether this temporary Fangcang shelter hospital is not built or delayed, the cumulative number of confirmed cases will both exceed 100,000, and the cumulative asymptomatic infections will both exceed 1 million. In addition, for a city of 10 million people, we obtain that if a permanent Fangcang shelter hospital with 17,784 beds is built ahead of epidemic, there will be no shortage of beds during the outbreak of Omicron. Our findings enrich the content of the impact of Fangcang shelter hospital beds on the spread of Omicron and confirm the correct policy adopted by the Chinese government.

Genome Instability-Associated Long Non-Coding RNAs Reveal Biomarkers for Glioma Immunotherapy and Prognosis.

Genome instability is a hallmark of tumors and is involved in proliferation, invasion, migration, and treatment resistance of many tumors. However, the relationship of genome instability with gliomas remains unclear. Here, we constructed genome instability-derived long non-coding RNA (lncRNA)-based gene signatures (GILncSig) using genome instability-related lncRNAs derived from somatic mutations. Multiple platforms were used to confirm that the GILncSig were closely related to patient prognosis and clinical characteristics. We found that GILncSig, the glioma microenvironment, and glioma cell DNA methylation-based stemness index (mDNAsi) interacted with each other to form a complex regulatory network. In summary, this study confirmed that GILncSig was an independent prognostic indicator for patients, distinguished high-risk and low-risk groups, and affected immune-cell infiltration and tumor-cell stemness indicators (mDNAsi) in the tumor microenvironment, resulting in tumor heterogeneity and immunotherapy resistance. GILncSig are expected to provide new molecular targets for the clinical treatment of patients with gliomas.

The Impact of Lockdown, Patient Classification, and the Large-Scale Case Screening on the Spread of the Coronavirus Disease 2019 (COVID-19) in Hubei.

The coronavirus disease (COVID-19) which emerged in Wuhan, China, in December 2019, is widely controlled now in China. However, the global epidemic is still severe. To study and comment on Hubei's approaches for responding to the disease, the paper considered some factors such as suspected cases (part of them are influenza patients or common pneumonia patients, etc.), quarantine, patient classification (three types), clinically diagnosed cases, and lockdown of Wuhan and Hubei. After that, the paper established an SELIHR model based on the surveillance data of Hubei published by the Hubei Health Commission from 10 January 2020 to 30 April 2020 and used the fminsearch optimization method to estimate the optimal parameters of the model. We obtained the basic reproduction number ℛ 0 = 3.1571 from 10 to 22 January. ℛ 0 was calculated as 2.0471 from 23 to 27 January. From 28 January to 30 April, ℛ 0 = 1.5014. Through analysis, it is not hard to find that the patients without classification during the period of confirmed cases will result in the cumulative number of cases in Hubei to increase. In addition, regarding the lockdown measures implemented by Hubei during the epidemic, our simulations also show that if the lockdown time of either Hubei or Wuhan is advanced, it will effectively curb the spread of the epidemic. If the lockdown measures are not taken, the total cumulative number of cases will increase substantially. From the results of the study, it can be concluded that the lockdown, patient classification, and the large-scale case screening are essential to slow the spread of COVID-19, which can provide references for other countries or regions.

Linear analysis of Atwood number effects on shear instability in the elastic-plastic solids.

The evolution of shear instability between elastic-plastic solid and ideal fluid which is concerned in oblique impact is studied by developing an approximate linear theoretical model. With the velocities expressed by the velocity potentials from the incompressible and irrotational continuity equations and the pressures obtained by integrating momentum equations with arbitrary densities, the motion equations of the interface amplitude are deduced by considering the continuity of normal velocities and the force equilibrium with the perfectly elastic-plastic properties of solid at interface. The completely analytical formulas of the growth rate and the amplitude evolution are achieved by solving the motion equations. Consistent results are performed by the model and 2D Lagrange simulations. The characteristics of the amplitude development and Atwood number effects on the growth are discussed. The growth of the amplitude is suppressed by elastic-plastic properties of solids in purely elastic stage or after elastic-plastic transition, and the amplitude oscillates if the interface is stable. The system varies from stable to unstable state as Atwood number decreasing. For large Atwood number, elastic-plastic properties play a dominant role on the interface evolution which may influence the formation of the wavy morphology of the interface while metallic plates are suffering obliquely impact.