Ultrafast Relaxation Dynamics of Photoexcited Dirac Fermion in The Three Dimensional Dirac Semimetal Cadmium Arsenide

Three dimensional (3D) Dirac semimetals which can be seen as 3D analogues of graphene have attracted enormous interests in research recently. In order to apply these ultrahigh-mobility materials in future electronic/optoelectronic devices, it is crucial to understand the relaxation dynamics of photoexcited carriers and their coupling with lattice. In this work, we report ultrafast transient reflection measurements of the photoexcited carrier dynamics in cadmium arsenide (Cd3As2), which is one of the most stable Dirac semimetals that have been confirmed experimentally. By using low energy probe photon of 0.3 eV, we probed the dynamics of the photoexcited carriers that are Dirac-Fermi-like approaching the Dirac point. We systematically studied the transient reflection on bulk and nanoplate samples that have different doping intensities by tuning the probe wavelength, pump power and lattice temperature, and find that the dynamical evolution of carrier distributions can be retrieved qualitatively by using a two-temperature model. This result is very similar to that of graphene, but the carrier cooling through the optical phonon couplings is slower and lasts over larger electron temperature range because the optical phonon energies in Cd3As2 are much lower than those in graphene

PO-184 Effects of resistance training and aerobic training on Fibronectin of Skeletal Muscle Extracellular Matrix and Satellite Cell in Aging Mice

Objective To investigate the effects of resistance and aerobic training on the content of fibronectin in skeletal muscle extracellular matrix and satellite cell in 9-month-old BALB/c mice, and then explore the effect of fibronectin content change on satellite cell and its intrinsic mechanism, which will provide a new research perspective and theoretical evidence for delaying sarcopenia. Methods 27 one-month-old BALB / c mice of SPF grade were purchased and fed for natural aging. At 9 months of age, the mice were divided into three groups randomly. Group R was resistance exercise training group (n=9), group A was aerobic exercise training group (n=9), and group C was control group (n=9). The load ladder model for resistance training in group R, the pyramid training program for 9 week training, 5 sets of load ladder training every time. 2 min for rest between sets, 1 min for rest between repetitions, 3 times a week. The treadmill training for aerobic training in group A for 9 weeks, the speed of 0.8km/h, 40min every time, 3 times a week. There is no training in group C. During the training, mouse grip strength was tested by the BIOSEB grip instrument once a week. After exercise intervention, the blood of mice was taken from the eyeball, and the gastrocnemius muscles were removed and placed in -80℃ temperature refrigerator to be freezed for tested . Immunofluorescence was used to detect FN and Pax7; The Real-time PCR was used to detect mRNA of FN, Sdc4, Fzd7, Wnt7a, c-Jun, Pax7; Western Blotting was used to detect the FN, sdc4, Fzd7, Wnt7a, c-Jun, p-c-Jun, Pax7 protein content. Results (1) Body weight, grip strength and skeletal muscle mass of mice: The body weight of group C and group R were significantly decreased after 9 weeks to compared with group A (P <0.05; P <0.05). The grip strength of group R and A was significantly increased in the ninth week to compared with group C, (P <0.01; P <0.05); The grip strength of group R and A in the ninth week were significantly higher than that in the first week (P <0.01; P <0.01)；  (2) FN in skeletal muscle extracellular matrix and it’s receptor Sdc4: The integrated optical density (IOD) of FN in group R was higher than that in group C and group A, but there was no significant difference among the three groups. The FN mRNA in group R was significantly increased to compared with group A (P<0.05). The FN protein content in group R was significantly increased to compared with group C and group A (P <0.01; P <0.01). There was no significant difference in the expression of Sdc4 mRNA in gastrocnemius muscle among the three groups. Compared with group C, the Sdc4 protein content was significantly down-regulated in both group R and group A (P<0.01; P<0.05). (3) Wnt7a/PCP signaling pathway: The Wnt7a mRNA and Wnt7a protein content in the gastrocnemius muscle of group R were significantly increased to compared with group C (P<0.05; P<0.01)). Compared with group A, Wnt7a protein content in group R was also significantly increased (P<0.05). There was no significant difference in Fzd7 mRNA in gastrocnemius muscle among the three groups; but the Fzd7 protein content in group R was significantly increased to compared with group A (P<0.05). The c-Jun mRNA in group R was significantly increased to compared with group C and A (P<0.05; P< 0.05). The content of c-Jun protein in group R was significantly increased to compared with group C and group A (P<0.01; P<0.01). The content of p-c-Jun protein in group R was significantly increased to compared with group C (P<0.05). (4) Pax7 : The number of Pax7 positive cells in group R was higher than that in group C and group A, but there was no significant difference among the three groups. Pax7 mRNA in group R and group A were significantly lower than that in group C (P<0.05; P<0.01), but Pax7 protein content in group R was significantly higher than group C and group A (P <0.05; P <0.05) Conclusions (1) Exercise can improve muscle strength of aging mice. (2) Resistance training can promote FN in skeletal muscle extracellular matrix and improve skeletal muscle extracellular matrix components of aging mice. (3) Resistance exercise training can promote Pax7 expression through the increase of FN and up-regulation of Wnt7a / PCP signaling pathway, thus make it possible for satellite cell proliferation

Entanglement Characteristic Time from Complex Moduli via i-Rheo <i>GT</i>

Tassieri et al. have introduced a novel rheological tool called “i-Rheo GT” that allows the evaluation of the frequency-dependent materials’ linear viscoelastic properties from a direct Fourier transform of the time-dependent relaxation modulus G(t), without artifacts. They adopted i-Rheo GT to exploit the information embedded in G(t) derived from molecular dynamics simulations of atomistic and quasi-atomistic models, and they estimated the polymers’ entanglement characteristic time (τe) from the crossover point of the moduli at intermediate times, which had never been possible before because of the poor fitting performance, at short time scales, of the commonly used generalized Maxwell models. Here, we highlight that the values of τe reported by Tassieri et al. are significantly different (i.e., an order of magnitude smaller) from those reported in the literature, obtained from either experiments or molecular dynamics simulations of different observables. In this work, we demonstrate that consistent values of τe can be achieved if the initial values of G(t), i.e., those governed by the bond-oscillation dynamics, are discarded. These findings have been corroborated by adopting i-Rheo GT to Fourier transform the outcomes of three different molecular dynamics simulations based on the following three models: a dissipative particle dynamics model, a Kremer–Grest model, and an atomistic polyethylene model. Moreover, we have investigated the variations of τe as function of (i) the ‘cadence’ at which G(t) is evaluated, (ii) the spring constant of the atomic bone, and (iii) the initial value of the shear relaxation modulus G(O). The ensemble of these results confirms the effectiveness of i-Rheo GT and provide new insights into the interpretation of molecular dynamics simulations for a better understanding of polymer dynamics

Risk Factors Associated with the Incidence of Ventricular Arrhythmias Complicating Acute Myocardial Infarction and Prognosis Analysis

Ventricular arrhythmias (VTA) usually occur following acute myocardial infarction (AMI). However, risk factors for VTA attack after AMI have been not well-recognized. The purpose of the study is to identify risk factors associated with the incidence of VTA complicating AMI. A total of 200 patients with AMI who were admitted to our hospital from February 2018 to February 2020 were retrospectively analyzed. These 200 patients were classified into a non-VTA group (n=140) and a VTA group (n=60) based on the occurrence of VTA within 24 after AMI. Patients in the VTA group were older than those in the non-VTA group. The VTA group had more numbers of WBCs and neutrophils than the non-VTA group. The level of serum potassium was lower, but the levels of cTnT and CK-MB were higher in the VTA group than in the non-VTA group. The VTA group presented an increase in proportions of anterior MI, TpTe, and proportions of Killip classification≥class II but a decline in LVEF when comparable to the non-VTA group. The two groups were not significantly different concerning other variables including sex, tobacco use, alcohol consumption, diabetes mellitus, hypertension, heart rate, Scr, SUA, BUN, PTL counts, TC, TG, HDL-C, LDL-C, D-dimer, BNP, LVS, LVP, and LVEDd. The levels of hsCRP, endothelin-1, and TNF-α were remarkably higher in the VTA group than in the non-VTA group (P<0.001). Multivariate logistic regression analysis was performed, with clinical variables including age, WBCs, neutrophils, serum potassium, cTnT, CK-MB, hsCRP, endothelin-1, TNF-α, anterior MI, TpTe, proportions of Killip classification≥class II, and LVEF as an independent variable and with the occurrence of VTA as a dependent variable. It was revealed that serum potassium, cTnT, CK-MB, hsCRP, endothelin-1, TpTe, proportions of Killip classification≥class II, and LVEF were independent risk factors of VTA complicating AMI. Compared with the non-VTA group, the incidence rate of simple left heart failure, total heart failure, stroke, and dyslipidemia in the VTA group was significantly higher than those in the non-VTA group (P<0.05). It was found that the proportion of all-cause deaths within one year outside the hospital was higher in the VAT group than in the non-VAT group (P<0.05). Collectively, the study demonstrates serum potassium, cTnT, CK-MB, hsCRP, endothelin-1, TpTe, proportions of Killip classification≥class II, and LVEF were independent risk factors of VTA complicating AMI

Identification and verification of microtubule associated genes in lung adenocarcinoma

Abstract Associated with high morbidity and mortality, lung adenocarcinoma (LUAD) is lacking in effective prognostic prediction and treatment. As chemotherapy drugs commonly used in clinics, microtubule-targeting agents (MTAs) are limited by high toxicity and drug resistance. This research aimed to analyze the expression profile of microtubule-associated genes (MAGs) in LUAD and explore their therapy efficiency and impact on prognosis. Key MAGs were identified as novel molecular targets for targeting microtubules. The LUAD project in The Cancer Genome Atlas (TCGA) database was used to identify differently expressed MAGs. On the one hand, a microtubule-related prognostic signature was constructed and validated, and its links with clinical characteristics and the immune microenvironment were analyzed. On the other hand, hub MAGs were obtained by a protein–protein interaction (PPI) network. Following the expression of hub MAGs, patients with LUAD were classified into two molecular subtypes. A comparison was made of the differences in half-maximal drug inhibitory concentration (IC50) and tumor mutational burden (TMB) between groups. In addition, the influence of MAGs on the anticancer efficacy of different therapies was explored. MAGs, which were included in both the prognosis signature and hub genes, were considered to have great value in prognosis and targeted therapy. They were identified by quantitative real-time polymerase chain reaction (qRT-PCR). A total of 154 differently expressed MAGs were discovered. For one thing, a microtubule-related prognostic signature based on 14 MAGs was created and identified in an external validation cohort. The prognostic signature was used as an independent prognostic factor. For another, 45 hub MAGs were obtained. In accordance with the expression profile of 45 MAGs, patients with LUAD were divided into two subtypes. Distinct differences were observed in TMB and IC50 values of popular chemotherapy and targeted drugs between subtypes. Finally, five genes were included in both the prognosis signature and hub genes, and identified by qRT-PCR. A microtubule-related prognosis signature that can serve as an independent prognostic factor was constructed. Microtubule subtype influenced the efficacy of different treatments and could be used to guide therapy selection. In this research, five key MAGs, including MYB proto-oncogene like 2 (MYBL2), nucleolar and spindle-associated protein 1 (NUSAP1), kinesin family member 4A (KIF4A), KIF15 and KIF20A, were verified and identified. They are promising biomarkers and therapeutic targets in LUAD

Synergistic pro-apoptotic effect of triptolide combined with doxorubicin in human breast cancer cell line MCF-7

Objective To study the effect of triptolide(TPL)combined with chemotherapy drug doxorubicin(DOX)on apoptosis of human breast cancer cell line MCF-7 and its molecular mechanism. Methods MCF-7 cells were treated with triptolide and different concentrations of doxorubicin alone or in combination. Cell viability was analyzed by CCK-8 method with the combination index calculated. Cell proliferation was detected by plate cloning formation assay. Cell apoptosis and cell cycle were detected by flow cytometry. The expressions of apoptosis-related proteins Bcl-2, Bax, cleaved caspase-3 and proteins in PI3K/AKT signaling pathway were analyzed by Western blot. Results Triptolide combined with different concentrations of doxorubicin significantly inhibited cell proliferation as compared with the doxorubicin group alone after incubation for 24, 48 and 72 hours(P＜0.05). The clone formation was restrained and the cell apoptosis rate was significantly higher(P＜0.01). The expressions of Bax and cleaved caspase-3 was up-regulated, and the expressions of Bcl-2, p-PI3K, p-AKT was down-regulated(P＜0.05). The cells were blocked in S phase after combination treatment of the two drugs(P＜0.05). Conclusions The combination of triptolide and doxorubicin significantly increases the sensitivity of MCF-7 cells to doxorubicin and promotes the apoptosis of cells, which might be related to the inhibition of PI3K/AKT signaling pathway

Preparation and Recent Developments of Ti/SnO2-Sb Electrodes

Ti/SnO2-Sb electrode, which is one of the dimensionally stable anode (DSA) electrodes, offers high specific conductivity, excellent electrocatalytic performance, and great chemical stability. For these reasons, Ti/SnO2-Sb electrode has been extensively studied in the fields of wastewater treatment. This review covers essential research work about the advanced oxidation technology and related DSA electrodes. It gives an overview of preparation methods of SnO2 electrodes, including sol-gel method, dip-coating method, electrodeposition method, chemical vapor deposition method, thermal decomposition method, magnetron sputtering method, and hydrothermal method. To extend service life and improve electrocatalytic efficiency, the review provides comprehensive details about the modification technologies of Ti/SnO2-Sb electrode, such as doping modification, composite modification, and structural modification. In addition, the review discusses common problems in industrial applications of Ti/SnO2-Sb electrode and highlights the promising outlook of Ti/SnO2-Sb electrode

4π-Periodic Supercurrent from Surface States in Cd3As2 Nanowire-Based Josephson Junctions

The combination of superconductivity and surface states in Dirac semimetal can produce a 4π-periodic supercurrent in a Josephson junction configuration, which can be revealed by the missing of odd Shapiro steps (especially the n=1 step). However, the suppression of the n=1 step is also anticipated in the high-power oscillatory regime of the ordinary 2π-periodic Josephson effect, which is irrelevant to the 4π-periodic supercurrent. Here, in order to identify the origin of the suppressed n=1 step, we perform the measurements of radio frequency irradiation on Nb-Dirac semimetal Cd3As2 nanowire-Nb junctions with continuous power dependence at various frequencies. Besides the n=1 step suppression, we uncover a residual supercurrent of first node at the n=0 step, which provides a direct and predominant signature of the 4π-periodic supercurrent. Furthermore, by tuning the gate voltage, we can modulate the surface and bulk state contribution and the visibility of the n=1 step. Our results provide deep insights to explore the topological superconductivity in Dirac semimetals

Diet-Induced High Serum Levels of Trimethylamine-N-oxide Enhance the Cellular Inflammatory Response without Exacerbating Acute Intracerebral Hemorrhage Injury in Mice

Trimethylamine-N-oxide (TMAO), an intestinal flora metabolite of choline, may aggravate atherosclerosis by inducing a chronic inflammatory response and thereby promoting the occurrence of cerebrovascular diseases. Knowledge about the influence of TMAO-related inflammatory response on the pathological process of acute stroke is limited. This study was designed to explore the effects of TMAO on neuroinflammation, brain injury severity, and long-term neurologic function in mice with acute intracerebral hemorrhage (ICH). We fed mice with either a regular chow diet or a chow diet supplemented with 1.2% choline pre- and post-ICH. In this study, we measured serum levels of TMAO with ultrahigh-performance liquid chromatography-tandem mass spectrometry at 24 h and 72 h post-ICH. The expression level of P38-mitogen-protein kinase (P38-MAPK), myeloid differentiation factor 88 (MyD88), high-mobility group box1 protein (HMGB1), and interleukin-1β (IL-1β) around hematoma was examined by western blotting at 24 h. Microglial and astrocyte activation and neutrophil infiltration were examined at 72 h. The lesion was examined on days 3 and 28. Neurologic deficits were examined for 28 days. A long-term choline diet significantly increased serum levels of TMAO compared with a regular diet at 24 h and 72 h after sham operation or ICH. Choline diet-induced high serum levels of TMAO did not enhance the expression of P38-MAPK, MyD88, HMGB1, or IL-1β at 24 h. However, it did increase the number of activated microglia and astrocytes around the hematoma at 72 h. Contrary to our expectations, it did not aggravate acute or long-term histologic damage or neurologic deficits after ICH. In summary, choline diet-induced high serum levels of TMAO increased the cellular inflammatory response probably by activating microglia and astrocytes. However, it did not aggravate brain injury or worsen long-term neurologic deficits. Although TMAO might be a potential risk factor for cerebrovascular diseases, this exploratory study did not support that TMAO is a promising target for ICH therapy.Peer Reviewe