We report the first experimental measurement on the thermal conductivity of strained monolayer graphene using optothermal Raman method. Biaxial tensile strain was achieved by applying a pressure ...difference across suspended monolayer graphene membranes. Experimental results demonstrate that, under 0.12%–0.27% strains, the in-plane thermal conductivity of monolayer graphene is sensitive to the applied biaxial strains. Under a 0.12% biaxial tensile strain, the thermal conductivity of suspended monolayer graphene drops approximately by 20% near 350K and 12% at about 500K. This study confirms the previous theoretical prediction that the thermal conductivity of monolayer graphene can be modified by applying tensile strains.
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Abstract When the hydraulic cylinder moves at high speed to the end of the stroke, it usually produces severe pressure, shock, and vibration, and makes the system very unstable, so the buffer device ...is often used to buffer the deceleration process of the hydraulic cylinder. In this paper, the cushioning process of a high-pressure hydraulic cylinder buffer device is modeled mathematically, the motion parameters in the cushioning process are calculated based on Simulink, and different structural parameters of the cylinder block are optimized and compared, to study the influence of structural parameters of the cushioning device on the cushioning process.
SARS-CoV-2: vaccines in the pandemic era Li, Dan-Dan; Li, Qi-Han
Military Medical Research/Military medical research,
01/2021, Letnik:
8, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused millions of infections and deaths worldwide since its emergence in December ...2019. As there is little or no natural immunity in the human population or specific anti-COVID-19 drugs, researchers from the government, academia and industry are developing vaccines at an unprecedented speed to halt the pandemic. In this review, the results of animal experiments and clinical trials on several vaccine technical platforms are summarized, and several challenges are also discussed to further promote the development, evaluation and application of vaccines during the challenging situation of the global pandemic.
► FTIR and 3D-EEM are used to analyse the main components of EPS in aerobic granule. ► Results indicate the importance of aromatic protein-like substances in the stable granular sludge. ► The isomers ...of carbohydrates (1110–1047cm−1) can be attributed to the aerobic sludge granulation.
In recent years, lots of the extracellular polymeric substances (EPS) related researches have focused on its role in the granulation and structural stability of aerobic sludge. Three-dimensional fluorescence spectrum (3D-EEM) and fourier transform infrared spectroscopy (FTIR) technologies were used to analyse the main components of sludge EPS during aerobic sludge granulation in this study. Results showed that the components of sludge EPS tended to be stable during aerobic sludge granulation. The peak F (Ex/Em=230/308.5) from 3D-EEM and the predominant spectral band at approximately 1517cm−1 from the FTIR spectra of the matured granular sludge indicated the importance of aromatic protein-like substances together, especially tyrosine in maintaining the stable structure of the granular sludge. Furthermore, the differences in the occurrence position and frequency of C–O bonds (1110–1047cm−1) observed during aerobic sludge granulation showed that the transformations between the isomers and other forms of carbohydrates may be attributed to the formation of aerobic granule.
Background
Biopsy Gleason score (GS) is crucial for prostate cancer (PCa) treatment decision‐making. Upgrading in GS from biopsy to radical prostatectomy (RP) puts a proportion of patients at risk of ...undertreatment.
Purpose
To develop and validate a radiomics model based on multiparametric magnetic resonance imaging (mp‐MRI) to predict PCa upgrading.
Study Type
Retrospective, radiomics.
Population
A total of 166 RP‐confirmed PCa patients (training cohort, n = 116; validation cohort, n = 50) were included.
Field Strength/Sequence
3.0T/T2‐weighted (T2W), apparent diffusion coefficient (ADC), and dynamic contrast enhancement (DCE) sequences.
Assessment
PI‐RADSv2 score for each tumor was recorded. Radiomic features were extracted from T2W, ADC, and DCE sequences and Mutual Information Maximization criterion was used to identify the optimal features on each sequence. Multivariate logistic regression analysis was used to develop predictive models and a radiomics nomogram and their performance was evaluated.
Statistical Tests
Student's t or chi‐square were used to assess the differences in clinicopathologic data between the training and validation cohorts. Receiver operating characteristic (ROC) curve analysis was performed and the area under the curve (AUC) was calculated.
Results
In PI‐RADSv2 assessment, 67 lesions scored 5, 70 lesions scored 4, and 29 lesions scored 3. For each sequence, 4404 features were extracted and the top 20 best features were selected. The radiomics model incorporating signatures from the three sequences achieved better performance than any single sequence (AUC: radiomics model 0.868, T2W 0.700, ADC 0.759, DCE 0.726). The combined mode incorporating radiomics signature, clinical stage, and time from biopsy to RP outperformed the clinical model and radiomics model (AUC: combined model 0.910, clinical model 0.646, radiomics model 0.868). The nomogram showed good performance (AUC 0.910) and calibration (P‐values: training cohort 0.624, validation cohort 0.294).
Data Conclusion
Radiomics based on mp‐MRI has potential to predict upgrading of PCa from biopsy to RP.
Level of Evidence
3
Technical Efficacy
Stage 5 J. Magn. Reson. Imaging 2020;52:1239–1248.
We report hyperpolarized Xe signal advancement by metal-organic framework (MOF) entrapment (Hyper-SAME) in aqueous solution. The 129Xe NMR signal is drastically promoted by entrapping the Xe into the ...pores of MOFs. The chemical shift of entrapped 129Xe is clearly distinguishable from that of free 129Xe in water, due to the surface and pore environment of MOFs. The influences from the crystal size of MOFs and their concentration in water are studied. A zinc imidazole MOF, zeolitic imidazole framework-8 (ZIF-8), with particle size of 110 nm at a concentration of 100 mg/mL, was used to give an NMR signal with intensity four times that of free 129Xe in water. Additionally, Hyper-SAME is compatible with hyperpolarized 129Xe chemical exchange saturation transfer. The 129Xe NMR signal can be amplified further by combining the two techniques. More importantly, Hyper-SAME provides a way to make detection of hyperpolarized 129Xe in aqueous solution convenient and broadens the application area of MOFs.
Schematic diagram of the preparation of injectable SP/PDA hydrogel and animal experiment. Dopamine powder was added to silk fibroin solution and the pH was adjusted to 8.5 by NaOH and reacted at ...37 °C for 72 h. After generating the spinal cord injury model, the hydrogel was injected into the injured site for repair.
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•An injectable SF/PDA composite hydrogel was successfully fabricated.•The hydrogel with 2 mg/mL DA had the best hippocampal neuron growth behavior.•The SF/PDA hydrogel possessed the capability of repairing SCI in vivo.•Self-polymerization and crosslink reaction mechanism coexisted in SF/PDA hydrogel.•The study provides experimental and theoretical basis for developing SCI implants.
Injectable hydrogels have potential applications for regenerating the injured spinal cord, but their performance needs to be further improved. In this study, an injectable silk fibroin/polydopamine (SF/PDA) composite hydrogel was fabricated via first Schiff base reaction between the amino groups of silk fibroin and the quinone structure of oxidized dopamine (DA), and then self-polymerization of free DA with SF-conjugated DA. The physicochemical properties of the hydrogel were characterized. The cytotoxicity and biocompatibility were evaluated using L929 fibroblasts and hippocampal neurons, respectively, and the expression levels of neurites-related proteins were analyzed by western blot. Finally, the effect of hydrogel on SCI repair was initially evaluated by in vivo animal experiment. With the increase of DA concentration, the hydrogels color became darker, the swelling rate, water uptake and the porosity decreased. Meanwhile, the Young's modulus continued to decrease when the DA concentration was increased from 0.5 mg/mL to 10 mg/mL, whereas rheological test showed the good injectability of the prepared hydrogels. NMR, FTIR and XPS confirmed that dopamine could combine with silk fibroin via Schiff base reaction and then polymerize to form the SF/PDA composite hydrogel. The hydrogels showed no cytotoxicity and the hippocampal neurons on hydrogel with 2 mg/mL DA displayed the largest axon length, the highest cell density and expression level of neuritis-related proteins. Further on, immunohistochemical staining showed initially that the prepared hydrogel possessed the capability of promoting SCI repair. In summary, the developed injectable SF/PDA hydrogel here may contribute to the potential application for promoting functional recovery of SCI, and provide important experimental and theoretical basis for developing SCI implants.
Scope
Endothelial dysfunction and inflammation are both common events occurring during the development of atherosclerosis. Previous studies have shown that urolithins, the intestinal microflora ...metabolites of ellagitannin, exhibit anti‐inflammation and antioxidative properties. This study aims to investigate the protective effect of urolithin A (UA) on ox‐LDL‐induced (where ox‐LDL is oxidized low‐density lipoprotein) endothelial dysfunction and possible modes of action.
Methods and results
Human artery endothelial cells were incubated with 50 μg/mL ox‐LDL and various concentrations of UA for 24 h. UA improved the productions of nitric oxide and endothelial nitric oxide synthase in a dose‐dependent manner. UA markedly reduced the expressions of ICAM‐1 (intercellular adhesion molecule 1) and MCP‐1 (monocyte chemotactic protein 1) and further attenuated THP‐1 (human acute monocytic leukemia cell line) cell adhesion. In addition, UA suppressed expressions of tumor necrosis factor α, interleukin 6, and endothelin 1, and increased PPAR‐γ (peroxisome proliferators activated receptor gamma) mRNA expression. Moreover, UA decreased miR‐27 expression, and overexpression of miR‐27 by adding pre‐miR‐27 abolished the ability of UA to improve ox‐LDL‐induced PPAR‐γ decrease. Furthermore, UA significantly downregulated phosphorylated ERK1/2 (where ERK is extracellular signal‐regulated kinase) while decreasing interleukin 6 level and elevating PPAR‐γ.
Conclusions
UA could alleviate endothelial dysfunction induced by ox‐LDL partially through modulating miR‐27 expression and ERK/PPAR‐γ pathway.
Urolithin A (UA) effectively protects human aortic endothelial cells (HAECs) against endothelial dysfunction induced by ox‐LDL. It markedly reduces the expressions of intercellular adhesion molecule (ICAM‐1) and monocyte chemotactic protein 1 (MCP‐1) and further attenuated THP‐1 (human acute monocytic leukemia cell line) cell adhesion. In addition, UA suppresses expressions of proinflammatory factors and increases peroxisome proliferators activated receptor gamma (PPAR‐γ) expression partially through downregulating miR‐27 expression and inactivating phosphorylated ERK1/2 (extracellular signal‐regulated kinase).
Ferroptosis is a new mode of regulated cell death, which is completely distinct from other cell death modes based on morphological, biochemical, and genetic criteria. This study evaluated the ...therapeutic role of ferroptosis in classic chemotherapy drugs, including the underlying mechanism.
Cell viabilitywas detected by using the methylthiazoltetrazlium dye uptake method. RNAiwas used to knockout iron-responsive element binding protein 2, and polymerase chain reaction, western blot was used to evaluate the efficiency. Intracellular reduced glutathione level and glutathione peroxidases activitywere determined by related assay kit. Intracellularreactive oxygen species levelswere determined by flowcytometry. Electron microscopywas used to observe ultrastructure changes in cell.
Among five chemotherapeutic drugs screened in this study, cisplatin was found to be an inducer for both ferroptosis and apoptosis in A549 and HCT116 cells. The depletion of reduced glutathione caused by cisplatin and the inactivation of glutathione peroxidase played the vital role in the underlying mechanism. Besides, combination therapy of cisplatin and erastin showed significant synergistic effect on their anti-tumor activity.
Ferroptosis had great potential to become a new approach in anti-tumor therapies and make up for some classic drugs, which open up a new way for their utility in clinic.
Ammonia (NH3), a toxic gas, has deleterious effects on chicken health in intensive poultry houses. MicroRNA can mediate inflammation. The complex molecular mechanisms underlying NH3 inhalation–caused ...inflammation in animal kidneys are still unknown. To explore the mechanisms, a broiler model of NH3 exposure was established. Kidney samples were collected on day 14, 28, and 42, and meat yield was evaluated on day 42. We performed histopathological examination, detected miR-6615-5p and mothers against decapentaplegic homolog 7 (Smad7), and determined inflammatory factors and cytokines in kidneys. The results showed that excess NH3 reduced breast weight and thigh weight, which indicated that excess NH3 impaired meat yield of broilers. Besides, kidney tissues displayed histopathological changes after NH3 exposure. Meanwhile, the increases of inducible nitric oxide synthase (iNOS) activity and nitric oxide content were obtained. The mRNA and protein expression of inflammatory factors, including nuclear factor-κB (NF-κB), cyclooxygenase-2, prostaglandin E synthases, and iNOS increased, indicating that NF-κB pathway was activated. T-helper (Th) 1 and regulatory T (Treg) cytokines were downregulated, whereas Th2 and Th17 cytokines were upregulated, suggesting the occurrence of Th1/Th2 and Treg/Th17 imbalances. In addition, we found that Smad7 was a target gene of miR-6615-5p in chickens. After NH3 exposure, miR-6615-5p expression was elevated, and Smad7 mRNA and protein expression were reduced. In summary, our results suggest that NH3 exposure negatively affected meat yield; and miR-6615/Smad7 axis and immune imbalance participated in NH3-induced inflammatory injury via the NF-κB pathway in broiler kidneys. This study is helpful to understand the mechanism of NH3-induced kidney injury and is meaningful to poultry health and breed aquatics.
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