Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 208
Filtrar
1.
ACS Nano ; 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33025784

RESUMO

Sluggish kinetics and limited reversible capacity present two major challenges for layered titanates to achieve satisfactory sodium-ion storage performance at subzero-temperatures (subzero-T). To facilitate sodiation dynamics and improve reversible capacity, we proposed an additive-free anode with Sn(II) located between layers. Sn-5s in interlayer-confining Sn(II), which has a larger negative charge, will hybridize with O-2p to trigger charge redistribution, thereby enhancing electronic conductivity. H-titanates with an open framework are designed to stabilize Sn(II) and restrain subsequent volume expansion, which could potentially surpass the capacity limitation of titanate-based materials via a joint alloying-intercalation reaction with high reversibility. Moreover, the generation of conductive Na14Sn4 and the expansion of interlayer spacing resulting from the interlayered alloying reaction are beneficial for charge transfer. These effects synergistically endow the modified sample with a considerably lower activation energy and a 3-fold increase in diffusion. Consequently, the designed anode delivers excellent subzero-T adaptability when compared to the unmodified sample, maintaining capacity retention of 91% after 1200 cycles at -20 °C and 90% after 850 cycles at -30 °C.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32865309

RESUMO

The colinearity of canonical modular polyketide synthases, which creates a direct link between multienzyme structure and the chemical structure of the biosynthetic end-product, has become a cornerstone of knowledge-based genome mining. Here we report genetic and enzymatic evidence for the remarkable role of an enoylreductase in the polyketide synthase for azalomycin F biosynthesis. This internal enoylreductase domain, previously identified as acting only in the second of two chain extension cycles on an initial iterative module, is shown here also to catalyse enoylreduction in trans within the next module. The mechanism for this rare deviation from colinearity appears to involve direct cross-modular interaction of the reductase with the longer acyl chain, rather than backtransfer of the substrate into the iterative module, suggesting an additional and surprising plasticity in natural PKS assembly-line catalysis.

3.
J Equine Vet Sci ; 92: 103174, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32797796

RESUMO

Serum and plasma are commonly used in clinical practice considering the widely accepted fact that the "normal" protein expression pattern of a healthy animal changes under disease conditions. We herein used a label-free mass spectrometry-based quantitative proteomics approach to characterize the serum proteome of donkeys. A total of 277 unique proteins were identified from 2,388 unique peptides. Gene ontology analyses showed that the most frequent processes were related to metabolic activities and biological regulation, response to stimulus, and immune system processes. The main annotated areas of origin were the extracellular region, extracellular region part, and organelle, and their molecular functions included binding, catalytic activity, and molecular function regulator. Analyses using the Clusters of Orthologous Groups for Eukaryotic Complete Genomes database indicated that the identified proteins could be categorized into three main groups: signal transduction mechanisms, amino acid transport and metabolism, and defense mechanisms. Most of the unique proteins were associated with the complement and coagulation cascades, and they participated in several disease-related metabolic pathways. Our results should be crucial for further analyses of changes in different physiological and pathophysiological conditions in donkeys.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32822310

RESUMO

Recently emerged deep learning methods have achieved great success in single image rain streaks removal. However, existing methods ignore an essential factor in the rain streaks generation mechanism, i.e., the motion blur leading to the line pattern appearances. Thus, they generally produce overderaining or underderaining results. In this article, inspired by the generation mechanism, we propose a novel rain streaks removal framework using a kernel-guided convolutional neural network (KGCNN), achieving state-of-the-art performance with a simple network architecture. More precisely, our framework consists of three steps. First, we learn the motion blur kernel by a plain neural network, termed parameter network, from the detail layer of a rainy patch. Then, we stretch the learned motion blur kernel into a degradation map with the same spatial size as the rainy patch. Finally, we use the stretched degradation map together with the detail patches to train a deraining network with a typical ResNet architecture, which produces the rain streaks with the guidance of the learned motion blur kernel. Experiments conducted on extensive synthetic and real data demonstrate the effectiveness of the proposed KGCNN, in terms of rain streaks removal and image detail preservation.

5.
Forensic Sci Int ; 315: 110430, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32738673

RESUMO

Recent advances in fire investigation have engendered significant interest in fire debris analysis. Many factors in fire scenes, however, may interfere with the identification of ignitable liquid residues (ILRs). Generally, all ILRs suffer unavoidably from thermal destruction in fires. In contrast to weathering, the thermal effects on ILRs involve evaporation, thermal degradation and other chemical reactions. In order to study the influence of the thermal environment in fire scenes on the stability of target compounds for ILRs identification, gasoline combustion residues were reheated at different temperatures and analyzed by gas chromatography-mass spectrometry (GC-MS) systematically. The results showed that polycyclic aromatic hydrocarbons (PAHs) and indanes were more susceptible to thermal destruction, and could not be detected effectively after heating. On the other hand, alkylbenzenes and condensed ring aromatics were comparatively more stable. When the temperature rose to 600 °C, almost all the target compounds were lost after reheating again for 2 min. The research provides an important reference for gasoline combustion residues identification, and care should be taken on the interpretation of results due to the inevitable thermal damage to ILRs in fires.

6.
Int Immunopharmacol ; 88: 106889, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32805693

RESUMO

B7-H4 and autophagy can regulate or be induced by the PI3K signaling pathway. However, the association between B7-H4 and autophagy in hepatocellular carcinoma (HCC)remains unclear. The aim of this work was to investigate whether B7-H4 regulates autophagy via the PI3K signaling pathway in HCC cells. Here, western blotting was used to measure the expression of the related proteins involved in changes in of autophagy and apoptosis, such as LC3, P62, cleaved caspase 3, cleaved PARP, BCL-2, and BAX in Huh7 and Hep3B cells. Additionally, PI3K/AKT/mTOR signaling pathway proteins were measured. Cell counting kit-8 and flow cytometry were used to analyze the effects of B7-H4 siRNA interference on cell proliferation with the interference of B7-H4 siRNA. We found that B7-H4 siRNA increased HCC cell apoptosis and autophagy, and reduced cell proliferation. Moreover, the apoptosis-related proteins cleaved caspase 3, cleaved PARP and BAX were increased and Bcl-2 was decreased after B7-H4 siRNA interference. The expression level of the autophagy-related protein LC3Ⅱ was upregulated, while expression of the autophagy adaptor P62 expression was decreased in B7-H4 siRNA-pretreated cells. Furthermore, our data revealed that B7-H4 regulated apoptosis and autophagy through the PI3K signaling pathway in HCC cells. Therefore, these results suggested that B7-H4 plays an important role in HCC progression by affecting cell apoptosis and autophagy.

8.
Surgeon ; 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32709425

RESUMO

BACKGROUND: It remains controversial on the optimal timing of cholecystectomy for patients with mild acute biliary pancreatitis. This study aimed at comparing the safety, feasibility, and cost-effectiveness of early laparoscopic cholecystectomy (ELC, within 72 h after admission) versus delayed laparoscopic cholecystectomy (DLC, beyond 72 h after admission) for patients with mild acute biliary pancreatitis. METHODS: We performed a systematic search in the following databases: PubMed, Embase, Web of Science, and Cochrane library. We only included articles from RCTs which designed to evaluate the complications, conversion to open cholecystectomy, recurrence of acute pancreatitis, the length of hospital stay, and costs between patients undergoing ELC and those undergoing DLC. We schemed to analyze data using STATA 15.0 with both the random-effects and the fixed-effect models. We computed relative risk (RR) and weighted mean difference (WMD) with 95% confidence intervals (CI) based on the intention-to-treat (ITT) analysis. RESULTS: A total of 4 studies involving 439 (215 vs 224) patients were included. The difference of complication rate [3.3% vs 3.2%; RR 1.03 (0.35, 3.01), P = 0.961] and rate of conversion to open cholecystectomy [3.8% vs 3.3%; RR 1.13 (0.37, 3.43), P = 0.830] are insignificant between patients who underwent ELC and ones who underwent DLC. The difference of rate of recurrence of acute pancreatitis is significant between ELC and DLC (2.17% vs 8.99%; RR 0.24 (0.08-0.70), P = 0.009). ELC does not shorten the length of hospital stay (random-effects model analysis: WMD -1.09 days (-2.67, 0.48), P = 0.173; fixed-effect model analysis: WMD -0.62 days (-1.00, -0.24), P = 0.001). CONCLUSION: Compared to DLC, ELC is equally safe and feasible both in complication rate and rate of conversion to open procedure, and significantly reduces the recurrence rate of acute pancreatitis. PROSPERO REGISTRATION NUMBER: CRD42018116239.

9.
Cell Death Dis ; 11(7): 507, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32632107

RESUMO

Phosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.

10.
Biomed Res Int ; 2020: 6953421, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32596356

RESUMO

Background: Receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) is significant in the activation of inflammation. Runt-related transcription factor 2 (Runx2) promotes the hepatic infiltration of macrophages in nonalcoholic fatty liver disease (NAFLD). We studied how RANKL affects Runx2-triggered macrophage infiltration in NAFLD. Method: 30 male C57BL/6J mice at 4 weeks of age were utilized in this study, 20 mice received a high-fat diet (HFD), and 10 mice received standard rodent chow over 8 months. The histopathologic features of the liver were identified by H&E, Oil red O, and Masson staining. Runx2, RANKL, and F4/80 were analyzed by western blot, real-time PCR, and immunohistochemistry in vivo, respectively. Lentivirus or siRNA was utilized for transwell assay to investigate the role of RANKL in Runx2-induced macrophage migration in vitro. Results: Compared to controls, during NAFLD development, HFD increased Runx2 and RANKL in vivo in NASH (P < 0.01). Meanwhile, a correlation between the expression of Runx2 and RANKL (P < 0.05) was evident. In addition, the hepatic infiltration of macrophages was increased upon HFD feeding, and analysis showed that the macrophage infiltration was correlated with the expression of Runx2 or RANKL (P < 0.05). In vitro, we found that overexpression or deficiency of Runx2 increased or decreased the production of RANKL in mHSCs. Then, transwell assay revealed that RANKL was involved in Runx2-induced macrophage migration. Conclusions: Overall, RANKL is involved in Runx2-triggered macrophage migration during NAFLD pathogenesis, which may provide an underlying therapeutic target for NAFLD.

11.
Phys Chem Chem Phys ; 22(23): 12987-12995, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32475997

RESUMO

Amorphous silicon (a-Si) is a type of common surface damages during the ultra-precision machining of monocrystalline Si. However, it is difficult to identify the amorphous damage of several nanometers by traditional detection methods, which severely hinders the performance improvement of Si-based products. In this study, ultrathin a-Si was found to act as a mask against etching in HF/HNO3 mixtures, resulting in the formation of protrusive hillocks. Reciprocating sliding on an atomic force microscope (AFM) was employed to simulate a material removal event in surface manufacturing. The effects of normal load, etching time and etchant concentration on selective etching were investigated to optimize the parameters for amorphous damage detection. The mechanisms for selective etching were further addressed based on high-resolution transmission electron microscopy (HRTEM) detection and comparative etching of different surface structures. Further analysis demonstrated that a lower dangling bond density of a-Si could result in the reduction of the dissolution rate, while deformed Si lattices, including stacking faults, dislocations and microcracks, could facilitate rapid selective etching. By the proposed selective etching, ultrathin amorphous damage and its spatial distributions can be rapidly identified with high resolution and low destruction. This study sheds new light on achieving a high-quality Si surface in ultra-precision machining.

13.
Artigo em Inglês | MEDLINE | ID: mdl-32510800

RESUMO

The first example of ferrocene analogues with two transition-metal metallole ligands of the general formula (η5 -C4 R4 M)2 Fe in a sandwich structure are reported. Specifically, dinickelaferrocene 2, a type of dimetallametallocene, is efficiently synthesized from the reaction of dilithionickelole 1 with FeBr2 or FeCl2 , presumably via a redox process, and is subjected to detailed experimental (single-crystal X-ray structural analysis, ICP-OES, magnetometry, 57 Fe Mössbauer, XPS) and theoretical (MOs, CDA, NICS, ICSS, and AICD) characterizations. Unlike ferrocene and its Cp ligands, the aromaticity of dinickelaferrocene and its nickelole ligands is accomplished by electron back-donation from the Fe 3d orbitals to the π* orbitals of nickelole. Taken together, this work describes a new class of metallaferrocene sandwich complexes and provides a novel approach to effect aromaticity that will contribute to further development of metallocene chemistry.

14.
J Int Med Res ; 48(5): 300060520925992, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32459154

RESUMO

OBJECTIVE: As a minimally invasive intervertebral fusion technique popularized in recent years, extreme lateral interbody fusion (XLIF) has various advantages. In this study, we describe the application and efficacy of XLIF for the treatment of thoracic tuberculosis (TB), as this may be an emerging treatment option for thoracic TB in the future. METHODS: We present the case of a 75-year-old man who had suffered from chest and back pain for 1 month. Imaging studies showed destruction of the T12 and L1 vertebral bodies and the T12-L1 intervertebral disc, accompanied by formation of a paravertebral abscess. After 2 weeks of standard anti-TB treatment, the patient underwent debridement of the lesions, XLIF, and percutaneous pedicle screw fixation. RESULTS: The patient's chest and back pain were significantly alleviated after the operation. The patient recovered well, and as of the most recent follow-up had no obvious limitation in thoracolumbar spine function. CONCLUSIONS: XLIF combined with percutaneous pedicle screw fixation for the treatment of thoracic TB can allow for TB lesion debridement, discectomy, and interbody fusion under direct visualization, and can effectively improve patient prognosis.

15.
Cell Commun Signal ; 18(1): 56, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32252758

RESUMO

BACKGROUND: AKT2 is one of the key molecules that involves in the insulin-induced signaling and the development of cancer. In B cells, the function of AKT2 is unclear. METHODS: In this study, we used AKT2 knockout mice model to study the role of AKT2 in BCR signaling and B cell differentiation. RESULTS: AKT2 promotes the early activation of B cells by enhancing the BCR signaling and actin remodeling. B cells from AKT2 KO mice exhibited defective spreading and BCR clustering upon stimulation in vitro. Disruption of Btk-mediated signaling caused the impaired differentiation of germinal center B cells, and the serum levels of both sepecific IgM and IgG were decreased in the immunized AKT2 KO mice. In addition, the actin remodeling was affected due to the decreased level of the activation of WASP, the actin polymerization regulator, in AKT2 KO mice as well. As a crucial regulator of both BCR signaling and actin remodeling during early activation of B cells, the phosphorylation of CD19 was decreased in the AKT2 absent B cells, while the transcription level was normal. CONCLUSIONS: AKT2 involves in the humoral responses, and promotes the BCR signaling and actin remodeling to enhance the activation of B cells via regulating CD19 phosphorylation. Video Abstract.

17.
Asian J Surg ; 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32171607

RESUMO

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

18.
J Equine Vet Sci ; 87: 102928, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32172918

RESUMO

It is important to assess the reproductive efficiency and improve the reproductive management to promote the donkey population development. The overall foaling-related parameters of jennies under smallholder farm conditions in China were hardly under investigation. A cross-sectional survey of randomly selected 694 smallholder farms was conducted in 40 villages in the north, east, and south areas of Western Liaoning Province and Eastern Inner Mongolia Autonomous Region between March and July, 2017. Foaling-related parameters were assessed such as the mean age at first foaling, foaling rate and foaling interval during 2014-2017. Only two-thirds of the adult jennies foaled during the 3-year survey period and delivered a foal every 1.9 years. The mean age at first foaling was 45.3 months. The lowest incidence of foaling rate was in coincidence with the peak of foaling. The overall mean values for the foaling rate and foaling interval were 75% and 500.5 days, respectively. Significant changes of foaling rates before the age of 15 years and foaling intervals in the first 8 parities were not observed. The results indicate that the jennies could maintain relatively fine foaling-related parameters under smallholder farm conditions in northeast of China. However, the foaling rates hardly remained high during the whole breeding season represented a major loss to the donkey breeding.

19.
Cell Res ; 30(1): 3-4, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31772274
20.
Nat Prod Res ; 34(9): 1331-1336, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-30663368

RESUMO

A new C19-diterpenoid alkaloid named hemsleyaline (1), along with fourteen known alkaloids (2-15), were isolated from the roots of Aconitum hemsleyanum Pritz. (Ranunculaceae), a herbal medicine in southwest China. Their structures were established on the basis of extensive spectroscopic analyses. Compound 1 showed mild cholinesterase inhibitory effect with IC50 value of 471 ± 9 µM.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA