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1.
Zhen Ci Yan Jiu ; 46(4): 266-71, 2021 Apr 25.
Artículo en Chino | MEDLINE | ID: mdl-33931989

RESUMEN

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zusanli" (ST36) and "Feishu" (BL13) on the expression of autophagy related proteins in the lung tissue of rats with chronic obstructive pulmonary disease (COPD), so as to explore the mechanism of EA underlying improvement of COPD. METHODS: Thirty male SD rats were randomly divided into normal, model and EA groups (n=10 in each group). The COPD model was established by intratracheal infusion of Lipopolysaccharide (LPS, 1 mg/kg) and exposure in cigarette smoke. EA was applied to bilateral ST36 and BL13 for 30 min, once every other day for 2 weeks. The pulmonary function (forced vital capacity ï¼»FVCï¼½, forced expiratory volume in 0.1 s and 0.3 s ï¼»FEV0.1, FEV0.3ï¼½, FEV0.1/FVC and FEV0.3/FVC) was detected by animal pulmonary function analysis system. Histopathological changes of the airway and lung were displayed by H.E. staining. Autophagosomes in the airway and lung tissues were observed by electron microscope. The expression of AMP activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), Unc-51 like autophagy activating kinase 1(ULK1), autophagy related protein ATG6(Beclin1)mRNAs in lung tissue were examined by quantitative real-time PCR. The expression of AMPK, mTOR, ULK1, Beclin1 and microtubule-associated protein 1 light chain 3 (LC3)proteins in lung tissue were examined by Western blot. The contents of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) in the broncho alveolar lavage fluid (BALF) were assayed by ELISA. RESULTS: Following modeling, the FVC, FEV0.1, FEV0.3, FEV0.1/FVC and FEV0.3/FVC levels were significantly decreased (P<0.01), the infiltration of inflammatory cells and the increase of autophagosomes were obvious in airway and lung tissue, the mRNA and protein expression of AMPK, ULK1, Beclin1 and the ratio of LC3Ⅱ/LC3Ⅰ were increased (P<0.01), while the mRNA and protein expression of mTOR were decreased (P<0.01), the contents of TNF-α and IL-6 in the BALF were increased in the model group compared with the normal group (P<0.01). After EA intervention, all the indexes mentioned above were completely reversed in the EA group relevant to the model group (P<0.01, P<0.05). CONCLUSION: EA at ST36 and BL13 can improve the lung function of COPD rats, which may be related to its effects in inhibiting the autophagy level and reducing the inflammation response in the lung.


Asunto(s)
Electroacupuntura , Enfermedad Pulmonar Obstructiva Crónica , Animales , Proteínas Relacionadas con la Autofagia , Pulmón , Masculino , Enfermedad Pulmonar Obstructiva Crónica/genética , Enfermedad Pulmonar Obstructiva Crónica/terapia , Ratas , Ratas Sprague-Dawley
2.
J Agric Food Chem ; 2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-33945277

RESUMEN

Excessive application of nitrogen (N) fertilizer is common in Chinese apple production. High N reduced the contents of soluble sugar and total flavonoids by 16.05 and 19.01%, respectively, resulting in poor fruit quality. Moreover, high N increased the total N and decreased the total C and C/N ratio of apple fruits. On the basis of the transcriptomic, proteomic, and metabolomic analyses, the global network was revealed. High N inhibited the accumulation of carbohydrates (sucrose, glucose, and trehalose) and flavonoids (rhamnetin-3-O-rutinoside, rutin, and trihydroxyisoflavone-7-O-galactoside) in fruits, and more C skeletons were used to synthesize amino acids and their derivatives (especially low C/N ratio, e.g., arginine) to be transferred to N metabolism. This study revealed new insights into the decline in soluble sugar and flavonoids caused by high N, and hub genes (MD07G1172700, MD05G1222800, MD16G1227200, MD01G1174400, and MD02G1207200) and hub proteins (PFK, gapN, and HK) were obtained.

3.
J Clin Invest ; 2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-33945512

RESUMEN

Down syndrome (DS), caused by trisomy of chromosome 21, occurs in 1 of every 800 live births. Early defects in cortical development likely account for the cognitive impairments in DS, although the underlying molecular mechanism remains elusive. Here, we performed histological assays and unbiased single-cell RNA sequencing (scRNA-seq) analysis on cerebral organoids derived from four euploid cell lines and from induced pluripotent stem cells (iPSCs) from three individuals with trisomy 21 to explore cell type-specific abnormalities associated with DS during early brain development. We found that neurogenesis was significantly affected based on diminished proliferation and decreased expression of layer II and IV markers in cortical neurons in the subcortical regions; this may be responsible for the reduced size of the organoids. Furthermore, suppression of the DSCAM-PAK1 pathway which showed enhanced activities in DS) via CRISPR/Cas9, CRISPRi or small-molecule inhibitor treatment reverses abnormal neurogenesis, thereby increasing the size of organoids derived from DS iPSCs. Our study demonstrated that 3D cortical organoids developed in vitro are a valuable model of DS and provided a direct link between dysregulation of the DSCAM-PAK1 pathway and developmental brain defects in DS.

4.
J Clin Lipidol ; 2021 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-33931376

RESUMEN

BACKGROUND: Current reference values for pediatric dyslipidemia used in China were not developed based on local population studies and did not consider age and sex differences. OBJECTIVE: In this study, we aimed to determine suitable reference values for total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and non-high-density lipoprotein cholesterol (nonHDL-C) for Chinese children and adolescents using a national multicenter school-based study. METHODS: A total of 15,830 students aged 6-17 years were recruited from seven provinces of China. Age- and sex-specific percentile values for each lipid indicator were derived based on levels measured in the fasting state, and percentile curves of each indicator were plotted using the LMS method. RESULTS: Serum lipid levels varied considerably with age in both sexes. Among boys, the cut-off value for high TC, nonHDL-C, LDL-C, and TG, based on the value of the 95th percentiles, ranged from 4.58 to 5.39, 3.34 to 3.99, 2.69 to 3.31, and 1.22 to 1.83 mmol/L, respectively; among girls, the cut-off value for high TC, nonHDL-C, LDL-C, and TC ranged from 5.01 to 5.39, 3.66 to 3.97, 2.97 to 3.32, and 1.41 to 1.93 mmol/L, respectively. The cut-point for low HDL-C ranged from 0.84 to 1.08 mmol/L in boys and from 0.89 to 1.04 mmol/L in girls. CONCLUSION: These findings may help to determine age- and sex-specific reference values for serum lipids among Chinese children and adolescents and provide valuable guidance for screening of dyslipidemia.

5.
Med Sci Monit ; 27: e929911, 2021 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-33935279

RESUMEN

BACKGROUND We performed the present study to better elucidate the correlation of reduced folate carrier-1 (RFC1) A80G (rs1051266) polymorphism with the risk of congenital heart disease (CHD). MATERIAL AND METHODS According to the designed search strategy, a systematic literature search was performed through the PubMed, Cochrane Library, Web of Science, EMBASE, CNKI, VIP, and Wan Fang databases to collect published case-control studies on the correlation between RFC1 A80G polymorphism and CHD. All relevant studies up to October 1, 2019 were identified. The odds ratio (OR) and 95% confidence interval (CI) of the genotype distribution were used as the effect indicators. RESULTS A total of 6 eligible studies was finally included in our meta-analysis, including 724 children with CHD, 760 healthy children, 258 mothers of the children with CHD, and 334 mothers of healthy control children. The meta-analysis revealed that for fetal analysis, only in the heterozygous model (GA vs GG, OR=1.36, 95% CI [1.06, 1.75], P=0.02) was RFC1 A80G polymorphism associated with risk of CHD. In maternal analysis, 3 genetic models of RFC1 A80G polymorphism increased the risk of CHD: the allelic model (A vs G, OR=1.36, 95% CI [1.07, 1.71], P=0.01), the homozygote model (AA vs GG, OR=2.99, 95%CI [1.06, 8.41], P=0.04), and the dominance model (GA+AA vs GG, OR=1.53, 95%CI [1.08, 2.16], P=0.02). CONCLUSIONS The maternal RFC1 A80G polymorphism has a strong correlation with CHD. Compared with the G allele, the A allele increases the risk of CHD by 0.36-fold.

6.
BMJ Open ; 11(5): e042843, 2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-33947727

RESUMEN

OBJECTIVE: To describe the prevalence and variations of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH) among children and adolescents (CADs) and young adults (YADs). DESIGN: A population-based observational study. SETTING: Annual cases and prevalence of NAFLD/NASH from 1990 to 2017, by sex, region and country were collected from the Global Burden of Disease database. MAIN OUTCOME MEASURES: The estimated annual percentage change, which was calculated by a regression line, was used to quantify the temporal trends in NAFLD/NASH burden among young people at the global, regional and national levels. RESULTS: Globally, NAFLD/NASH incidence increased from 19.34 million in 1990 to 29.49 million in 2017 among CADs, with an annual increase of 1.35%. Additionally, in YADs, the number of cases and NAFLD/NASH prevalence significantly increased during this period, independent of sex and region. The greatest NAFLD/NASH increase was in North Africa and the Middle East. Almost all countries showed an increasing trend from 1990 to 2017, with the most pronounced increase observed in the developed regions. CONCLUSIONS: The epidemiology of NAFLD/NASH in young people has changed considerably over the last three decades. Both the prevalence and number of cases have increased irrespective of sex, age and region. This phenomenon can result in a predictable increase in chronic liver disease burden in the near future. Understanding the prevalence of NAFLD/NASH and its variations is of paramount importance to develop strategies to implement public health policy.

7.
Oxid Med Cell Longev ; 2021: 6640108, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33953833

RESUMEN

Criticality is considered a dynamic signature of healthy brain activity that can be measured on the short-term timescale with neural avalanches and long-term timescale with long-range temporal correlation (LRTC). It is unclear how the brain dynamics change in adult moyamoya disease (MMD). We used BOLD-fMRI for LRTC analysis from 16 hemorrhagic (H MMD) and 34 ischemic (I MMD) patients and 25 healthy controls. Afterwards, they were examined by EEG recordings in the eyes-closed (EC), eyes-open (EO), and working memory (WM) states. The EEG data of 11 H MMD and 13 I MMD patients and 21 healthy controls were in good quality for analysis. Regarding the 4 metrics of neural avalanches (e.g., size (α), duration (ß), κ value, and branching parameter (σ)), both MMD subtypes exhibited subcritical states in the EC state. When switching to the WM state, H MMD remained inactive, while I MMD surpassed controls and became supercritical (p < 0.05). Regarding LRTC, the amplitude envelope in the EC state was more analogous to random noise in the MMD patients than in controls. During state transitions, LRTC decreased sharply in the controls but remained chaotic in the MMD individuals (p < 0.05). The spatial LRTC reduction distribution based on both EEG and fMRI in the EC state implied that, compared with controls, the two MMD subtypes might exhibit mutually independent but partially overlapping patterns. The regions showing decreased LRTC in both EEG and fMRI were the left supplemental motor area of H MMD and right pre-/postcentral gyrus and right inferior temporal gyrus of I MMD. This study not only sheds light on the decayed critical dynamics of MMD in both the resting and task states for the first time but also proposes several EEG and fMRI features to identify its two subtypes.

8.
Biomed Res Int ; 2021: 8894498, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33954202

RESUMEN

Drug- and herb-induced liver injury (DILI and HILI) is an increasingly common and serious condition. Here, data for DILI and HILI patients from two large tertiary hospitals were retrospectively analyzed. Patient characteristics, causes and severity of DILI and HILI, the correlation between expression of p62 and the severity of DILI and HILI, treatment of DILI and HILI, and the prognostic factors of DILI and HILI were studied. A total of 82 patients with DILI and HILI were recruited for the study. Most patients presented with hepatocellular injury, followed by cholestatic injury and mixed injury. Our results indicate that traditional Chinese medicine or herbal and dietary supplements were the prevalent causal agents of HILI, which was characterized by higher frequencies of hepatocellular injury. Expression of p62 in the liver correlated with the severity of DILI and HILI. Improvements in the results of the liver enzymatic tests correlated with alanine transaminase (ALT) levels upon the first diagnosis of DILI and HILI and with the hepatocellular type of DILI and HILI. In conclusion, we provide an epidemiological assessment of DILI and HILI based on causality using the updated RUCAM on patients from two hospitals in China. ALT levels at first diagnosis and the hepatocellular type of injury may be prognostic factors of DILI and HILI.

9.
IEEE Trans Cybern ; PP2021 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-33961574

RESUMEN

In this article, we propose a weakly supervised low-rank representation (WSLRR) method for hyperspectral anomaly detection (HAD), which formulates deep learning-based HAD into a low-lank optimization problem not only characterizing the complex and diverse background in real HSIs but also obtaining relatively strong supervision information. Different from the existing unsupervised and supervised methods, we first model the background in a weakly supervised manner, which achieves better performance without prior information and is not restrained by richly correct annotation. Considering reconstruction biases introduced by the weakly supervised estimation, LRR is an effective method for further exploring the intricate background structures. Instead of directly applying the conventional LRR approaches, a dictionary-based LRR, including both observed training data and hidden learned data drawn by the background estimation model, is proposed. Finally, the derived low-rank part and sparse part and the result of the initial detection work together to achieve anomaly detection. Comparative analyses validate that the proposed WSLRR method presents superior detection performance compared with the state-of-the-art methods.

10.
Stem Cell Res Ther ; 12(1): 257, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33933157

RESUMEN

BACKGROUND: Cutaneous wound healing and regeneration have become a recognized health challenge in the world, which causes severe damage to the mental and physical health of patients. Human adipose-derived mesenchymal stem cells (hADSC) play an essential role in wound healing via their paracrine function. Exosomes secreted by hADSC may contribute to this progress. In this study, we investigated the potential clinical application roles of hADSC and hADSC-derived exosomes (hADSC-Exo) in cutaneous wound healing. METHODS: hADSC-Exo was isolated from human hADSC by ultracentrifugation. Mice were subjected to a full-thickness skin biopsy experiment and treated with either control vehicle or hADSC or hADSC-Exo by smearing administration (sm) or subcutaneous administration (sc) or intravenous administration (iv). The efficacy of hADSC and hADSC-Exo on wound healing was evaluated by measuring wound closure rates, histological analysis. RESULTS: Combined application of local hADSC-Exo smearing and hADSC/hADSC-Exo intravenous administration offered the additional benefit of promoting wound healing, accelerating re-epithelialization, reducing scar widths, and enhancing angiogenesis and collagen synthesis. Either topical application of hADSC-Exo or systemic administration with hADSC/hADSC-Exo appeared more effective in stimulating cell proliferation, inhibiting cell apoptosis and inflammation, and promoting skin elasticity and barrier integrity, with increased genes expression of PCNA, VEGF, collagen III, Filaggrin, Loricrin, and AQP3, with decreased genes expression of TNF-alpha. CONCLUSION: Our findings suggest that the combined administration of hADSC/hADSC-Exo can facilitate cutaneous wound healing and reduce scar formation. These data provide the first evidence for the feasibility of smearing of hADSC-Exo as a cell-free therapy in treating cutaneous wounds, and the potential clinical value of combined administration of hADSC/hADSC-Exo.

11.
Theor Appl Genet ; 2021 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-33934211

RESUMEN

KEY MESSAGE: Rose has 19 MLO genes. Of these, RhMLO1 and RhMLO2 were shown to be required for powdery mildew infection, which suggests their potential as susceptibility targets towards disease resistance. Powdery mildew, caused by Podosphaera pannosa, is one of the most serious and widespread fungal diseases for roses, especially in greenhouse-grown cut roses. It has been shown that certain MLO genes are involved in powdery mildew susceptibility and that loss of function in these genes in various crops leads to broad-spectrum, long-lasting resistance against this fungal disease. For this reason, these MLO genes are called susceptibility genes. We carried out a genome-wide identification of the MLO gene family in the Rosa chinensis genome, and screened for allelic variants among 22 accessions from seven different Rosa species using re-sequencing and transcriptome data. We identified 19 MLO genes in rose, of which four are candidate genes for functional homologs in clade V, which is the clade containing all dicot MLO susceptibility genes. We detected a total of 198 different allelic variants in the set of Rosa species and accessions, corresponding to 5-15 different alleles for each of the genes. Some diploid Rosa species shared alleles with tetraploid rose cultivars, consistent with the notion that diploid species have contributed to the formation of tetraploid roses. Among the four RhMLO genes in clade V, we demonstrated using expression study, virus-induced gene silencing as well as transient RNAi silencing that two of them, RhMLO1 and RhMLO2, are required for infection by P. pannosa and suggest their potential as susceptibility targets for powdery mildew resistance breeding in rose.

12.
Nano Lett ; 2021 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-33914549

RESUMEN

Holes in nanowires have drawn significant attention in recent years because of the strong spin-orbit interaction, which plays an important role in constructing Majorana zero modes and manipulating spin-orbit qubits. Here, from the strongly anisotropic leakage current in the spin blockade regime for a double dot, we extract the full g-tensor and find that the spin-orbit field is in plane with an azimuthal angle of 59° to the axis of the nanowire. The direction of the spin-orbit field indicates a strong spin-orbit interaction along the nanowire, which may have originated from the interface inversion asymmetry in Ge hut wires. We also demonstrate two different spin relaxation mechanisms for the holes in the Ge hut wire double dot: spin-flip co-tunneling to the leads, and spin-orbit interaction within the double dot. These results help establish feasibility of a Ge-based quantum processor.

13.
J Am Chem Soc ; 2021 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-33929189

RESUMEN

The capture of sustainable energy from a salinity gradient, in particular, using renewable biomass-derived functional materials, has attracted significant attention. In order to convert osmotic energy to electricity, many membrane materials with nanofluidic channels have been developed. However, the high cost, complex preparation process, and low output power density still restrict the practical application of traditional membranes. Herein, we report the synthesis of highly flexible and mechanically robust nanofiber-arrays-based carbonaceous ordered mesoporous nanowires (CMWs) through a simple and straightforward soft-templating hydrothermal carbonization approach. This sequential superassembly strategy shows a high yield and great versatility in controlling the dimensions of CMWs with the aspect ratio changes from about 3 to 39. Furthermore, these CMWs can be used as novel building blocks to construct functional hybrid membranes on macroporous alumina. This nanofluidic membrane with asymmetric geometry and charge polarity exhibits low resistance and high-performance energy conversion. This work opens a solution-based route for the one-pot preparation of CMWs and functional heterostructure membranes for various applications.

14.
ACS Appl Mater Interfaces ; 13(15): 18175-18183, 2021 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-33826289

RESUMEN

Light-driven hydrogel actuators show potential applications because their spatiotemporal precision and contact-free manner, especially for near-infrared light (NIR), can be focused on a specific area, which possesses tunable intensity and strong penetrability. Herein, we propose a novel NIR-responsive hydrogel actuator incorporating Fe3+/tannic acid (Fe3+/TA) as a photothermal transducer into the poly(N-isopropylacrylamide) (PNIPAAm) hydrogel via photo-cross-linking and subsequent immersion in FeCl3 solution. TA contains abundant pyrogallol and catechol groups, which can be linked to PNIPAAm through hydrogen bonds during in situ polymerization; moreover, as a mediator, TA can form metal-phenolic networks with Fe3+ via the coordination between catechol and metal ions, endowing the PNIPAAm gel with enhanced mechanical properties as well as NIR-responsive photothermal effect. We demonstrated that introduction of Fe3+/TA maintained the volume phase transition temperature of the hydrogel around 32 °C and guaranteed its deformation behaviors upon NIR irradiation. Furthermore, a higher concentration level of BIS and Fe3+ were verified to facilitate a stronger photothermal capacity of the hydrogels. Therefore, under NIR irradiation, Fe3+/TA within the hydrogel converted NIR light into heat, and the local high temperature in the irradiated region would cause the petals of the "snowflake"-shaped hydrogel to bend upward perpendicular to the horizontal plane within 1 min, possessing excellent repeatability. This study puts forward a new idea of preparing NIR-responsive hydrogel actuators based on Fe3+/TA, which show promising application in the fields of biomimetic devices, flowing control, and soft robotics.

15.
Bioorg Chem ; 111: 104886, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33836342

RESUMEN

Our present and previous phytochemical investigations on Leptopus lolonum have resulted in the isolation of almost 30 phenylpropanoid-conjugated pentacyclic triterpenoids (PCPTs). During the continuous study on PCPTs, this kind of triterpenoid ester is considered as a natural product with low toxicity because of it's widely distribution in natural plants and edible fruits including kiwi fruit, durian, jujube, pawpaw, apple and pear. In the present work, we report the isolation, structural elucidation and cytotoxic evaluation of four new PCPTs (1-4) which obtained from L. lolonum. In addition, the possible biosynthesis pathway for 28-norlupane triterpenoid and potent effect of phenylpropanoid moiety for increasing the cytotxic effect of triterpenoids were also discussed. Among these compounds, compound 1 exhibited the highest cytotoxic effect on HepG2 cells with IC50 value of 11.87 µM. Further flow cytometry and western blot analysis demonstrated that 1 caused G1 cell cycle arrest by up-regulated the expression of phosphorylated p53 protein in HepG2 cells and induced cell apoptosis via MAPK and Akt pathways. These results emphasized the potential of PCPTs as lead compounds for developing anti-cancer drugs.

16.
Sheng Li Xue Bao ; 73(2): 208-216, 2021 Apr 25.
Artículo en Chino | MEDLINE | ID: mdl-33903882

RESUMEN

The transcription factor X-box binding protein-1 (XBP1) plays a key role in unfolded protein reaction. This study was aimed to investigate the expression pattern and regulation of XBP1 in the mouse uterus during early pregnancy. The methods of immunohistochemistry (IHC) and real time quantitative RT-PCR were used to test XBP1 expression in early pregnancy, artificial decidualization, oestrous cycle and hormone-regulated mouse models. The results showed that XBP1 was spatiotemporally expressed in mouse uterus during early pregnancy. The XBP1 protein was mainly detected in the luminal and glandular epithelia on days 1-4 of pregnancy, and was strongly detected in the decidual area on days 5-8 of pregnancy. Similarly, XBP1 expression was also mainly expressed in decidual cells following artificial decidualization. During the oestrous cycle, Xbp1, Xbp1u, and Xbp1s mRNA was predominantly present in proestrus. In the ovariectomized uterus, the expression of XBP1 in luminal and glandular epithelia was up-regulated after estrogen treatment. These results suggest that XBP1 is associated with embryo implantation and decidualization during early pregnancy in mice, and the expression of XBP1 in luminal and glandular epithelia may be regulated by estrogen.


Asunto(s)
Decidua , Implantación del Embrión , Animales , Estrógenos , Femenino , Ratones , Embarazo , ARN Mensajero/genética , Útero
17.
J Am Chem Soc ; 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33909970

RESUMEN

The Nazarov electrocyclization reaction is a convenient, widely used method for construction of cyclopentenones. In the past few decades, catalytic asymmetric versions of the reaction have been extensively studied, but the strategies used to control the position of the double bond limit the substituent pattern of the products and thus the synthetic applications of the reaction. Herein, we report highly enantioselective silicon-directed Nazarov reactions which were cooperatively catalyzed by a Lewis acid and a chiral Brønsted acid. The chiral cyclopentenones we synthesized using this method generally cannot be obtained by means of other catalytic enantioselective reactions, including previously reported methods for enantioselective Nazarov cyclization. The silicon group in the dienone substrate stabilized the ß-carbocation of the intermediate, thereby determining the position of the double bond in the product. Mechanistic studies suggested that the combination of Lewis and Brønsted acids synergistically activated the dienone substrate and that the enantioselectivity of the reaction originated from a chiral Brønsted acid promoted proton transfer reaction of the enol intermediate.

18.
Nanotechnology ; 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33910177

RESUMEN

Sintered nano-copper is becoming a promising candidate as thermal interface material (TIM) for die attaching in high power electronics. It exhibits much higher thermal conductivity and operating temperature than conventional TIMs based on polymer and solder joints, and higher electromigration resistance and lower cost than sintered nano-silver TIM. However, the performance of existing sintered nano-copper is lower than expected because of high porosity resulted from poor sintering of copper particles with oxide shell. Here we demonstrate a method of improving the thermal conductivity of sintered copper by addition of graphene/Cu-CuxO with controllable diameter of ~163 nm. The measured thermal conductivity of the sintered composite TIM is enhanced by up to 123.5% compared with that of sintered pure copper. It can be understood as a result of the formation of graphene heat transfer network in sintered TIM. In addition, the C-O-Cu bonds formed at the interface between graphene and copper nanoparticles are critical for improving thermal performance as well as electrical and mechanical performance of the TIM. The developed TIM can be widely used in high power electronic packaging especially for high temperature applications, including IGBT, SiC and GaN power devices.

19.
Technol Cancer Res Treat ; 20: 1533033820960755, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33896245

RESUMEN

OBJECTIVE: The incidence of skin squamous cell carcinoma (SSCC) has recently been increasing, with diverse clinical manifestations.SSCC could metastasize to lymph nodes or other organs, posing a great threat to life. The present study was designed to investigate the function and underlying mechanism of muscleblind-like protein 1 (MBNL1) in skin squamous cell carcinoma. METHODS: SCL-1 cell was used for vitro model and transfected with MBNL1 or siMBNL1 plasmids. MTT Assays, LDH activity ELISA, and Transwell chamber migration experiment were used to confirm the effects of MBNL1 on cell growth of SCL-1 cell. Western blot analysis was used to analyze the mechanism of MBNL1 in SCL-1 cell. RESULTS: Down-regulation of MBNL1 promoted cell metastasis of SSCC, while up-regulation of MBNL1 reduced cell metastasis of SSCC in vitro. Down-regulation of MBNL1 suppressed the protein expression of T cell intracellular antigen (TIAL1), myogenic determinant 1 (MyoD1) and Caspase-3 in vitro. Consistent with these observations, inhibition of TIAL1 or MYOD1 expression attenuated the effects of MBNL1 in SSCC. CONCLUSION: The present study revealed that MBNL1 suppressed thecancer metastatic capacity of SSCC via by TIAL1/MYOD1/Caspase-3 signaling pathways.

20.
Food Funct ; 12(8): 3516-3526, 2021 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-33900329

RESUMEN

Nobiletin is abundant in citrus peels and demonstrates good anti-obesity bioactivity. However, its anti-obesity mechanisms still remain unclear. This study aims to explore the bidirectional interaction between nobiletin and gut microbiota in mice fed with a high-fat diet. For the colonic bioconversion, more demethylated metabolites with higher biological activity were found in feces than nobiletin in the 48 h excretion study and 8 week consecutive dosing study. Moreover, long-term oral intake of nobiletin would modify the gut microbiota with improved demethylation ability and enhanced production of short chain fatty acids. The comparison of metabolite profiles in mouse liver and feces indicated that gut microbiota might have a higher biotransformation activity on nobiletin than the host. Two bacteria at the genus level, Allobaculum and Roseburia, remained enriched by nobiletin after the 4- and 8-week feedings. They might correlate with the enhanced nobiletin biotransformation and actively contribute to the health benefits of nobiletin in vivo. These results suggested that the bidirectional interaction of nobiletin and gut microbiota played an important role on the anti-obesity effect of nobiletin.

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