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1.
Opt Express ; 29(3): 4681-4699, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33771039

RESUMO

Injection locking and pulling characteristics of a long-loop optoelectronic oscillator (OEO) that has a large number of closely-spaced longitudinal modes are theoretically analyzed and experimentally evaluated. A differential phase equation that relates the phase difference between the OEO and the injected microwave signal to its instantaneous beat angular frequency is derived in the time domain. Based on the differential phase equation, both the locking and pulling characteristics of an injection-locked OEO are studied, and the phase noise performance is analyzed. It is found that the locking and pulling performance depends upon three parameters, the initial frequency difference between the frequency of the signal generated by the free-running OEO and frequency of the injected microwave signal, the voltage ratio between the signal generated by the free-running OEO and the injected microwave signal, and the Q factor of the free-running OEO. The phase noise performance depends upon the locking range, the phase noise performance of the free-running OEO as well as that of the injected microwave signal. The analysis is validated experimentally. Excellent agreement is found between the theoretical analysis and the experimental demonstration.

2.
J Am Chem Soc ; 143(13): 5099-5105, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33761746

RESUMO

The controllable B-H bond activation of carboranes has long been a compelling challenge. However, as the symmetry of para-carborane places the same charge on all of its ten boron atoms, controlling the regiochemistry of B-H bond activation in these molecules has remained out of reach ever since their discovery. Herein, we describe how to use steric effects to achieve a regioselective process for B-H activation of para-carborane. In this strategy, B(2,8)-H or B(2,7)-H activation patterns were achieved by taking advantage of the π-π interactions between pyridine ligands. Interestingly, by employing host-guest interactions in metallacage compounds, B(2,8)-H bond activation could be avoided and exclusive B(2,9)-H bond activation can be achieved. Steric hindrance was also found to be beneficial for regioselective B(2,8)-H bond activation in metallacage species. In this work, we demonstrate that steric effects can be a promising driving force for controllable activation of the B-H bonds of carboranes and open new opportunities in this field.

3.
Stem Cell Res Ther ; 12(1): 170, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33691762

RESUMO

BACKGROUND: Skin wounds in diabetic patients hardly recover. Accumulating evidence has shown that mammalian target of rapamycin (mTOR) pathway and myeloid-derived suppressor cells (MDSCs) are involved in inflammatory-related response. INK128 is a novel mTOR kinase inhibitor in clinical development. However, the exact roles of MDSCs and INK128 in healing wound of diabetic patients are unclear. METHODS: Mice models of normal, diabetic, and diabetic+INK128 were constructed. Bone marrow (BM)-derived macrophages and RAW264.7 cell line co-cultured with MDSCs, which were induced at different conditions. Flow cytometry, western blot, quantitative real-time PCR, and immunohistochemical analysis were performed. RESULTS: Diabetic mice (DM) had a slower recovery rate, thinner epidermis and dermis, and less blood vessels than those of normal mice. MDSCs were abnormally accumulated in DM, mTOR was activated in MDSCs of DM, and the cells were treated with high glucose. Moreover, mTOR signaling inhibitor INK128 could promote wound healing through reducing the MDSCs. MDSC function was disordered in DM and high-glucose environments, while INK128 could help retrieve their function. Furthermore, high glucose and other factors in DM could promote M-MDSC differentiation to M1 pro-inflammatory macrophage cells, thus inhibiting wound healing. The differentiation, which was dependent on mTOR signaling, could be reversed by INK128. CONCLUSION: INK128 is potential to be developed as a clinical strategy to promote wound healing of diabetic patients.

4.
Chem Soc Rev ; 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33656017

RESUMO

Characterization of materials at the nanoscale plays a crucial role in in-depth understanding the nature and processes of the substances. Mass spectrometry (MS) has characterization capabilities for nanomaterials (NMs) and nanostructures by offering reliable multi-dimensional information consisting of accurate mass, isotopic, and molecular structural information. In the last decade, MS has emerged as a powerful nano-characterization technique. This review comprehensively summarizes the capabilities of MS in various aspects of nano-characterization that greatly enrich the toolbox of nano research. Compared with other characterization techniques, MS has unique capabilities for real-time monitoring and tracking reaction intermediates and by-products. Moreover, MS has shown application potential in some novel aspects, such as MS imaging of the biodistribution and fate of NMs in animals and humans, stable isotopic tracing of NMs, and risk assessment of NMs, which deserve update and integration into the current knowledge framework of nano-characterization.

6.
Medicine (Baltimore) ; 100(3): e23941, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33545969

RESUMO

ABSTRACT: This study aimed to compare the effectiveness and safety of reduced-port laparoscopic surgery (RPLS) and conventional multi-port laparoscopic (CMPLS) surgery in the treatment of gastric diseases.The PubMed, Embase, Cochrane Library, Web of Science, and Chinese Biomedical Literature databases were systematically searched for randomized controlled trials, cohort studies, and case control studies on the use of RPLS vs conventional multi-port laparoscopic surgery in treating gastric diseases from their inception until March 10, 2019. The evaluated outcomes were the operative time, blood loss, length of hospital stay, number of dissected lymph nodes, postoperative complications, and conversions. All of these were compared using Stata software version 12.0.A total of 18 studies were included, which involved 2938 patients. In studies referring to the comparison between RPLS and CMPLS in treating gastric diseases, the former showed significantly inferior in terms of operative time (P = .011) and number of dissected lymph nodes (P = .031); but superior results in terms of the estimated blood loss (P = .000) and length of hospital stay (P = .001) than the latter did; however, the rates of postoperative complications (P = .830) and conversions (P = .102) were not statistically significant between the 2 groups.RPLS and CMPLS showed comparable effectiveness and safety in the treatment of gastric diseases in our meta-analysis. Based on the current evidence, we believe that RPLS is an efficacious surgical alternative to CMPLS in the management of gastric diseases because of the shorter hospital stay and reduced blood loss. However, large-scale, well-designed, multicenter studies are needed to further confirm the results of this study.


Assuntos
Equipamentos e Provisões/normas , Laparoscopia/instrumentação , Laparoscopia/normas , Gastropatias/cirurgia , Resultado do Tratamento , Equipamentos e Provisões/efeitos adversos , Humanos , Laparoscopia/métodos , Tempo de Internação/tendências , Duração da Cirurgia , Complicações Pós-Operatórias/etiologia , Gastropatias/complicações
7.
Biochim Biophys Acta Mol Basis Dis ; 1867(6): 166107, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33621651

RESUMO

The melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R), known as neural melanocortin receptors, have been implicated to be critical components of the hypothalamic leptin-melanocortin pathway and related to obesity pathogenesis. In contrast to extensive evidence from physiologic, biological, genetic studies demonstrating that MC4R is a critical regulator in obesity, whether MC3R mutation causes obesity is still controversial. In the present study, we screened for coding variants in the MC3R gene of 176 obese individuals (mean BMI 34.84 ± 0.19 kg/m2) and 170 lean controls (mean BMI 20.70 ± 0.08 kg/m2) to assess the prevalence of MC3R mutations in a Chinese cohort. Two novel mutations, A33D (c.C98 > A) and A259T (c.G775 > A), were identified in two subjects with morbid obesity, respectively. A259T was also identified in the carrier's sibling. In vitro functional studies showed that A33D was defective in the cAMP signaling pathway, whereas A259T MC3R had defective maximal binding and cAMP generation in response to NDP- and α-MSH, likely due to decreased cell surface expression. In addition, we showed that A33D and A259T were biased receptors and defect in constitutive activation of ERK1/2 signaling through MC3R might be a cause for morbid obesity. Our sequencing and co-segregation studies combined with comprehensive functional analysis demonstrated that A259T might be predisposing to obesity. Further investigations in larger cohorts will be needed in order to define this association and the specific phenotypic characteristics resulting from these mutations.

8.
Mol Cell Probes ; 56: 101706, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33617946

RESUMO

AIM: Acute liver failure (ALF) is a life-threatening acute liver injury (ALI) with high mortality. Gensenoside Rg1 (G-Rg1) effects on Lipopolysaccharide- (LPS-) and d-galactose-(D-gal-) induced ALI, but its effects on ALF remained unclear. This paper aimed to validate its possible efficacy on ALF prevention. METHODS: For in vivo studies, histological examination was performed using hematoxylin-eosin (H&E) staining, and alanine aminotransferase (ALT), aspartate aminotransminase (AST), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) contents were measured. Levels of inflammatory cytokines tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6) were quantified via enzyme-linked immunosorbent assay (ELISA). Human bronchial epithelial cell line BEAS-2B was used for ALF model in vitro and its viability was measured by MTT assay. Expressions of high mobility group box 1 (HMGB1) and toll-like receptor 4-Nuclear Factor-κB (TLR4-NF-κB) pathway-related proteins were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot as needed. RESULTS: G-Rg1 relieved LPS- and D-gal-induced hepatic injury, and reduced ALT, AST and MDA levels but upregulated SOD and GSH levels, with downregulation on TNF-α and IL-6 levels. Expressions of HMGB1, TLR4 and NF-κB pathway-related proteins were also down-regulated after G-Rg1 treatment both in vivo and in vitro, while BEAS-2B cell viability was increased. However, overexpressed HMGB1 reversed the effects of G-Rg1 treatment in vitro. CONCLUSION: G-Rg1 had a protective effect against LPS- and D-gal-induced ALF both in vitro and in vivo, which might be related to inhibited HMGB1-mediated TLR4-NF-κB Pathway. These discoveries suggested that G-Rg1 could be a potential agent for prevention against ALF.

9.
Small ; : e2007264, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33470516

RESUMO

Developing a rapid and low cost approach to access atomically dispersed metal catalysts (ADMCs) supported by carbon is important but still challenging. Here, an electric flash strategy using high voltage for the rapid fabrication of carbon-supported ADMCs within 1 min is reported. Continuous plasma arc results in nitrogen-doped carbon ultrathin nanosheets, while an intermittent spark pulse constructs carbon hollow nanospheres via blasting effect, and both structures are decorated with atomically dispersed cobalt. The latter catalyst shows a half-wave potential of 0.887 V versus RHE (47 mV higher than commercial Pt/C) in an oxygen reduction reaction (ORR) in alkaline media. The authors' work paves the way to rapid synthesis of carbon-supported ADMCs at both low cost and mass production.

10.
J Am Chem Soc ; 143(2): 1119-1125, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33382617

RESUMO

Two molecular metalla-knots containing over 500 non-hydrogen atoms (especially 16 RhIII ions) and one molecular Borromean ring were obtained in high yields facilitated by multiple intermolecular interactions between their components. The syntheses rely on the strategic selection of the nonlinear dipyridyl ligand 2,7-di(pyridin-4-yl)-9H-fluorene (L1) as precursor, and the structures of the assemblies were confirmed by detailed X-ray crystallographic analysis. Subsequently, replacing L1 with the bulkier ligand 4,4'-(9,9-dimethyl-9H-fluorene-2,7-diyl)dipyridine (L2) led to the formation of three tetranuclear metallocycles in high yields on account of the weakened π-π stacking interactions between the naphthacene/anthracene and fluorene moieties, which in turn confirmed the significance of stacking interactions in the construction of the molecular 818 metalla-knots and the molecular Borromean ring.

11.
Nano Lett ; 2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33305576

RESUMO

The electrocatalytic carbon dioxide reduction reaction (CO2RR) offers an attractive route to fuels and feedstocks from renewable energy. Gold is active for the electrochemical CO2RR to CO, while the competing hydrogen evolution reaction is unavoidable. Here, we report a synergistic strategy, via introducing atomically dispersed Fe to tune the electronic structure of the Au nanoparticle, to improve the CO selectivity. By using operando X-ray absorption and infrared spectroscopies, we reveal the dynamic structural evolution and the adsorption of reactant intermediates at the single-atom Fe1/Au interface. During the reaction, the interaction between Fe and Au atoms becomes stronger, and the Fe1/Au synergies affect the adsorption of reaction intermediates, thus improving the selectivity of CO up to 96.3% with a mass activity of 399 mA mg-1. These results highlight the significant importance of synergistic modulation for advancing the single-atom decorated nanoparticle catalysis.

12.
Small ; : e2005571, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-33258310

RESUMO

Planar metal clusters possess high metal utilization, distinct electronic properties, and catalytic functions from their 3D counterparts. However, synthesis of these materials is challenging due to much elevated surface free energies. Here it is reported that silica supported planar bilayer Pt-CoOx subnano clusters, consisting of approximately one atomic layer of Pt and one CoOx layer on top, can be achieved by employing strong-electrostatic interactions during impregnation and precisely-controlled CoOx coating using atomic layer deposition. Such bilayer structure is unambiguously confirmed by electron microscopy and in situ X-ray absorption fine spectroscopy which is never reported before. This synthetic approach can be extended to another eight permutations of planar metal-oxide subnano clusters. The resulting bilayer catalysts, owing to unique electronic properties and the abundant metal-oxide interfaces created, exhibit excellent catalytic performances in the reactions of preferential oxidation of CO in H2 and selective hydrogenation of acetylene, by showing much higher selectivity and intrinsic activities at least 8 and 48 times greater than those conventional oxide coated 3D metal clusters/nanoparticles, highlighting the advances of bilayer interfacial structure. These findings open a new avenue to design abundant and highly active metal-oxide interfaces for advanced metal catalysis.

13.
Huan Jing Ke Xue ; 41(12): 5448-5457, 2020 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-33374061

RESUMO

Residual levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in karst groundwater in Nanshan Laolongdong were measured using a gas chromatograph equipped with a micro-63Ni electron capture detector to determine the residual characteristics including concentration, distribution, and source of OCPs and PCBs. Results revealed that the total concentration range of OCPs was 34.8-623.2 ng·L-1, and the mean value was 215.6 ng·L-1, among which the total concentration ranges of HCHs, DDTs, and other OCPs were 8.2-23.6, 4.5-363.7, and 22.2-235.9 ng·L-1, respectively, and the mean values were 15.9, 104.5, and 95.3 ng·L-1; the total concentration range of PCBs was 6.0-40.7 ng·L-1, and the mean value was 16.8 ng·L-1. Overall, the pollution of OCPs and PCBs was above average; the results of multiple comparisons revealed that statistically significant differences occurred in the concentration of some OCPs and PCBs. The pollution levels in the water of each sampling point in the study area were quite different; however, the seasonal distribution of OCPs and PCBs was relatively uniform. Source analyses revealed that HCHs' source was the input of lindane in the surrounding environment, DDTs recently originated from illegal use of industrial DDT, other OCPs originated from atmospheric deposition and agricultural input, and PCBs' sources included both historical remains and enterprise production processes. The results of Pearson correlation analyses revealed that some organo-halogen pollutants were homologous or had similar sources and decomposition mechanisms. According to health risk assessment model, drinking water in the study area would not cause obvious harm to human health, but children were more sensitive to pollutants than adults.


Assuntos
Água Subterrânea , Hidrocarbonetos Clorados , Praguicidas , Bifenilos Policlorados , Poluentes Químicos da Água , Criança , China , Monitoramento Ambiental , Humanos , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Bifenilos Policlorados/análise , Poluentes Químicos da Água/análise
14.
Artigo em Inglês | MEDLINE | ID: mdl-33372329

RESUMO

Metallic bismuth has drawn attention as a promising alloying anode for advanced potassium ion batteries (PIBs). However, serious volume expansion/electrode pulverization and sluggish kinetics always lead to its inferior cycling and rate properties for practical applications. Therefore, advanced Bi-based anodes via structural/compositional optimization and sur-/interface design are needed. Herein, we develop a bottom-up avenue to fabricate nanoscale Bi encapsulated in a 3D N-doped carbon nanocages (Bi@N-CNCs) framework with a void space by using a novel Bi-based metal-organic framework as the precursor. With elaborate regulation in annealing temperatures, the optimized Bi@N-CNCs electrode exhibits large reversible capacities and long-duration cyclic stability at high rates when evaluated as competitive anodes for PIBs. Insights into the intrinsic K+ -storage processes of the Bi@N-CNCs anode are put forward from comprehensive in situ characterizations.

15.
World J Surg Oncol ; 18(1): 331, 2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33308239

RESUMO

OBJECTIVES: To fully assess the quality of the guidelines for the management of malignant pleural effusions (MPE) and ascites and reveal the heterogeneity of recommendations and possible reasons among guidelines. METHODS: A systematic search was performed in the database to obtain guidelines for the management of MPE and ascites. The AGREE IIGtool was used to assess the quality of these guidelines. The Measurement Scale of Rate of Agreement (MSRA) was introduced to assess the scientific agreement of formulated recommendations for the management of MPE and ascites among guidelines, and evidence supporting these recommendations was extracted and analyzed. RESULTS: Nine guidelines were identified. Only 4 guidelines scored more than 60% and are worth recommending. Recommendations were also heterogeneous among guidelines for the management of MPE, and the main reasons were the different emphases of the recommendations for the treatment of MPE, the contradictions in recommendations, and the unreasonably cited evidence for MPE. CONCLUSIONS: The quality of the management guidelines for patients with MPE and malignant ascites was highly variable. Specific improvement of the factors leading to the heterogeneity of recommendations will be a reasonable and effective way for developers to upgrade the recommendations in the guidelines for MPE.

16.
Opt Lett ; 45(21): 5986-5989, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33137050

RESUMO

It is a daunting challenge to realize ultraviolet C (UVC) lasing (i.e., has a wavelength range from 200 to 275 nm) from upconversion nanocrystals due to their low upconversion efficiency. Here, we fabricate Ba2LaF7:Yb3+(90mol%), Tm3+(5mol%) upconversion nanocrystals from amorphous borosilicate glass to support emission at ∼263nm under 980 nm ns laser excitation. The excitation threshold can be further reduced from ∼130 to ∼26.5mJ/cm2 by using a cylindrical microcavity. We also found that the growth of defect-free Ba2LaF7 nanocrystals with a high concentration of codoping Yb3+ and Tm3+ ions inside high optical damage threshold borosilicate glass is the key to achieving room-temperature UVC upconversion lasing under high-intensity excitation.

17.
J Am Chem Soc ; 142(44): 18946-18954, 2020 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-33006897

RESUMO

Molecular figure-eight knot (notation: 41) is extremely rare and presents great synthetic challenge due to its essentially complicated entanglement. To solve this synthetic problem, a quadruple stacking strategy was developed. Herein, we report the efficient self-assembly of figure-eight knots induced by quadruple stacking interactions, through the combination of four carefully selected naphthalenediimide (NDI)-based pyridyl ligands and Cp*Rh building blocks bearing large conjugated planes in a single-step strategy. Notably, slight size adjustment of the Cp*Rh units was found to affect the stability of the figure-eight knots in methanol. Additionally, reversible structural transformations between these figure-eight knots and corresponding metallorectangles could be achieved by concentration changes and solvent- and guest-induced effects. X-ray crystallographic data and NMR spectroscopy provide full confirmation of these phenomena.

18.
Sensors (Basel) ; 20(19)2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-33007891

RESUMO

Blood pressure monitoring is one avenue to monitor people's health conditions. Early detection of abnormal blood pressure can help patients to get early treatment and reduce mortality associated with cardiovascular diseases. Therefore, it is very valuable to have a mechanism to perform real-time monitoring for blood pressure changes in patients. In this paper, we propose deep learning regression models using an electrocardiogram (ECG) and photoplethysmogram (PPG) for the real-time estimation of systolic blood pressure (SBP) and diastolic blood pressure (DBP) values. We use a bidirectional layer of long short-term memory (LSTM) as the first layer and add a residual connection inside each of the following layers of the LSTMs. We also perform experiments to compare the performance between the traditional machine learning methods, another existing deep learning model, and the proposed deep learning models using the dataset of Physionet's multiparameter intelligent monitoring in intensive care II (MIMIC II) as the source of ECG and PPG signals as well as the arterial blood pressure (ABP) signal. The results show that the proposed model outperforms the existing methods and is able to achieve accurate estimation which is promising in order to be applied in clinical practice effectively.

19.
Sensors (Basel) ; 20(21)2020 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-33113788

RESUMO

New ongoing rural construction has resulted in an extensive mixture of new settlements with old ones in the rural areas of China. Understanding the spatial characteristic of these rural settlements is of crucial importance as it provides essential information for land management and decision-making. Despite a great advance in High Spatial Resolution (HSR) satellite images and deep learning techniques, it remains a challenging task for mapping rural settlements accurately because of their irregular morphology and distribution pattern. In this study, we proposed a novel framework to map rural settlements by leveraging the merits of Gaofen-2 HSR images and representation learning of deep learning. We combined a dilated residual convolutional network (Dilated-ResNet) and a multi-scale context subnetwork into an end-to-end architecture in order to learn high resolution feature representations from HSR images and to aggregate and refine the multi-scale features extracted by the aforementioned network. Our experiment in Tongxiang city showed that the proposed framework effectively mapped and discriminated rural settlements with an overall accuracy of 98% and Kappa coefficient of 85%, achieving comparable and improved performance compared to other existing methods. Our results bring tangible benefits to support other convolutional neural network (CNN)-based methods in accurate and timely rural settlement mapping, particularly when up-to-date ground truth is absent. The proposed method does not only offer an effective way to extract rural settlement from HSR images but open a new opportunity to obtain spatial-explicit understanding of rural settlements.

20.
Hortic Res ; 7: 154, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33082961

RESUMO

Resistant cultivars have played important roles in controlling Fusarium wilt disease, but the roles of rhizosphere interactions among different levels of resistant cultivars are still unknown. Here, two phenotypes of cucumber, one resistant and one with increased susceptibility to Fusarium oxysporum f.sp. cucumerinum (Foc), were grown in the soil and hydroponically, and then 16S rRNA gene sequencing and nontargeted metabolomics techniques were used to investigate rhizosphere microflora and root exudate profiles. Relatively high microbial community evenness for the Foc-susceptible cultivar was detected, and the relative abundances of Comamonadaceae and Xanthomonadaceae were higher for the Foc-susceptible cultivar than for the other cultivar. FishTaco analysis revealed that specific functional traits, such as protein synthesis and secretion, bacterial chemotaxis, and small organic acid metabolism pathways, were significantly upregulated in the rhizobacterial community of the Foc-susceptible cultivar. A machine-learning approach in conjunction with FishTaco plus metabolic pathway analysis revealed that four organic acids (citric acid, pyruvate acid, succinic acid, and fumarate) were released at higher abundance by the Foc-susceptible cultivar compared with the resistant cultivar, which may be responsible for the recruitment of Comamonadaceae, a potential beneficial microbial group. Further validation demonstrated that Comamonadaceae can be "cultured" by these organic acids. Together, compared with the resistant cultivar, the susceptible cucumber tends to assemble beneficial microbes by secreting more organic acids.

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