Three-dimensional upper bound limit analysis of underground cavities using nonlinear Baker failure criterion

A generalized nonlinear Baker failure criterion is employed with the upper bound limit analysis to study the surrounding rock stability of underground cavities. A three-dimensional(3D) failure mode is established by extending the two-dimensional(2D) failure mode, which offers an upper bound expression of the surrounding rock pressure. This method is validated with a series of examples before the influence of four parameters of scale parameter, curvature parameter, shift parameter and lateral pressure coefficient, on the surrounding rock pressure is analyzed. According to these results, failure ranges of the underground cavities are determined. The following conclusions are reached:(1) the proposed approach is more accurate to predict surrounding rock pressure than the Mohr-Coulomb failure criterion;(2) the surrounding rock with large scale parameter, curvature parameter, shift parameter, and lateral pressure coefficient can lead to a more stable underground cavity;(3) the failure range in 3D mode can be predicted according to the upper bound solutions.

Apoptosis of mesenchymal stem cells is regulated by Rspo1 via the Wnt/β-catenin signaling pathway

Objective: The aim of this study was to investigate the effect and possible mechanism of action of roof plate-specific spondin1 (Rspo1) in the apoptosis of rat bone marrow mesenchymal stem cells (BMSCs). Methods: Osteogenic and adipogenic differentiation of BMSCs was identified by Alizarin Red and Oil Red O staining, respectively. BMSC surface markers (cluster of differentiation 29 [CD29], CD90, and CD45) were detected using flow cytometry. BMSCs were transfected with an adenoviral vector encoding Rspo1 (BMSCs-Rspo1 group). The expression levels of Rspo1 gene and Rspo1 protein in the BMSCs-Rspo1 group and the two control groups (untransfected BMSCs group and BMSCs-green fluorescent protein [GFP] group) were analyzed and compared by quantitative polymerase chain reaction and Western blot. The occurrence of apoptosis in the three groups was detected by flow cytometry and acridine orange-ethidium bromide (AO-EB) double dyeing. The activity of the Wnt/β-catenin signaling pathway was evaluated by measuring the expression levels of the key proteins of the pathway (β-catenin, c-Jun N-terminal kinase [JNK], and phospho-JNK). Results: Osteogenic and adipogenic differentiation was confirmed in cultured BMSCs by the positive expression of CD29 and CD90 and the negative expression of CD45. Significantly increased expression levels of Rspo1 protein in the BMSCs-Rspo1 group compared to those in the BMSCs (0.60 ± 0.05 vs. 0.13 ± 0.02;t=95.007, P=0.001) and BMSCs-GFP groups (0.60 ± 0.05 vs. 0.10 ± 0.02;t=104.842, P=0.001) were observed. The apoptotic rate was significantly lower in the BMSCs-Rspo1 group compared with those in the BMSCs group ([24.06 ± 2.37]% vs.[40.87 ± 2.82]%;t =49.872, P =0.002) and the BMSCs-GFP group ([24.06 ± 2.37]% vs.[42.34 ± 0.26]%;t =62.358, P =0.001). In addition, compared to the BMSCs group, the protein expression levels of β-catenin (2.67 ± 0.19 vs. 1.14 ± 0.14;t =-9.217, P =0.000) and JNK (1.87 ± 0.17 vs. 0.61 ± 0.07;t =-22.289, P =0.000) were increased in the BMSCs-Rspo1 group. Compared to the BMSCs-GFP group, the protein expression levels of β-catenin (2.67 ± 0.19 vs. 1.44 ± 0.14;t =-5.692, P =0.000) and JNK (1.87 ± 0.17 vs. 0.53 ± 0.06;t =-10.589, P =0.000) were also upregulated in the BMSCs-Rspo1 group. Moreover, the protein expression levels of phospho-JNK were increased in the BMSCs-Rspo1 group compared to those in the BMSCs group (1.89 ± 0.10 vs. 0.63 ± 0.09;t =-8.975, P =0.001) and the BMSCs-GFP group (1.89 ± 0.10 vs. 0.69 ± 0.08;t =-9.483, P =0.001). Conclusion: The Wnt/β-catenin pathway could play a vital role in the Rspo1-mediated inhibition of apoptosis in BMSCs.

Identification and characterization of murine adipose tissue-derived somatic stem cells of Shenque(CV8)acupoint

Background:Shenque(CV8)acupoint is located on the navel and has been therapeutically used for more than 2000 years in Traditional Chinese Medicine(TCM).However,clinical research on the underlying therapeutic molecular mechanisms of the CV8 acupoint lags far behind.This study aimed to study the mechanisms of umbilical acupoint therapy by using stem cells.Methods:The morphological characteristics of CV8 acupoint were detected under a stereomicroscope using hematoxylin and eosin(H&E)staining.Oil Red,Masson,and immunohistochemical staining on multi-layered slices were used to identify the type of cells at the CV8 acupoint.Cell proliferation was measured by a cell counting kit-8(CCK-8)method.Flow cytometry and immunohistochemistry were used for cell identification.Induced differentiation was used to compare the differentiation of cells derived from CV8 acupoint and non-acupoint somatic stem cells into other cell types,such as osteogenic,adipogenic,and neural stem cell-like cells.Results:Morphological observations showed that adipose tissues at the linea alba of the CV8 acupoint in mice had a mass-like distribution.Immunohistochemical staining confirmed the distribution of stem cell antigen-1(Sca-1)positive cells in the multi-layered slices of CV8 acupoint tissues.Cells isolated from adipose tissues at the CV8 acupoint exhibited high expression of Sca-1 and CD44 and low expression of CD31 and CD34,and these cells possessed osteogenic,adipogenic,and neurogenic stem cell-like cell differentiation ability.The cell proliferation(day 4:0.5138±0.0111 vs.0.4107±0.0180,t=8.447,P=0.0011;day 5:0.6890±0.0070 vs.0.5520±0.0118,t=17.310,P<0.0001;day 6:0.7320±0.0090 vs.0.6157±0.0123,t=13.190,P=0.0002;and day 7:0.7550±0.0050 vs.0.6313±0.0051,t=42.560,P<0.0001),adipogenic([9.224±0.345]%vs.[3.933±1.800]%,t=5.000,P=0.0075),and neurogenic stem cell-like cell differentiation(diameter<50 mm:7.2000±1.3040 vs.2.6000±0.5477,t=7.273,P<0.0001;diameter 50–100 mm:2.6000±0.5477 vs.1.0000±0.7071,t=4.000,P=0.0039;and diameter>100 mm:2.6000±0.5477 vs.0.8000±0.8367,t=4.025,P=0.0038)were significantly enhanced in somatic stem cells derived from the CV8 acupoint compared to somatic stem cells from the groin non-acupoint.However,cells possessed significantly weaker osteogenicity([2.697±0.627]%vs.[7.254±0.958]%,t=6.893,P=0.0023)in the CV8 acupoint group.Conclusions:Our study showed that CV8 acupoint was rich with adipose tissues that contained abundant somatic stem cells.The biological examination of somatic stem cells derived from the CV8 acupoint provided novel insights for future research on the mechanisms of umbilical therapy.

A rapid colloidal gold immunochromatographic assay for the diagnosis of coronavirus disease 2019

Coronavirus disease 2019(COVID-19),caused by a severe acute respiratory syndrome coronavirus-2(SARS-CoV-2),which can lead to pneumonia and severe acute respiratory syndrome,continues to spread across the globe.[1]Due to strict precautionary measures,the epidemic situation of COVID-19 has been initially controlled in China.However,the numbers of confirmed positive cases of COVID-19 and deaths are increasing in other countries.In fact,the SARS-CoV-2 is more contagious than severe acute respiratory syndrome coronavirus(SARS-CoV)[2]and Middle East respiratory syndrome coronavirus(MERSCoV).[3]Therefore,the rapid and accurate identification of pathogenic viruses plays a vital role in controlling epidemics.Computed tomography imaging and some hematologic parameters are the initial markers for COVID-19 infection,[4,5]while viral nucleic acid detection by reverse transcription-polymerase chain reaction is used as a gold standard for the clinical diagnosis of suspected cases.