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1.
Sci Technol Adv Mater ; 24(1): 2196240, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37090847

RESUMO

Graphdiyne (GDY) is an emerging two-dimensional carbon allotrope featuring a direct bandgap and fascinating physical and chemical properties, and it has demonstrated its promising potential in applications of catalysis, energy conversion and storage, electrical/optoelectronic devices, etc. In particular, the recent breakthrough in the synthesis of large-area, high-quality and ultrathin GDY films provides a feasible approach to developing high-performance electrical devices based on GDY. Recently, various GDY-based electrical and optoelectronic devices including multibit optoelectronic memories, ultrafast nonvolatile memories, artificial synapses and memristors have been proposed, in which GDY plays a crucial role. It is essential to summarize the recent breakthrough of GDY in device applications as a guidance, especially considering that the existing GDY-related reviews mainly focus on the applications in catalysis and energy-related fields. Herein, we review GDY-based novel memory and neuromorphic devices and their applications in neuromorphic computing and artificial visual systems. This review will provide an insight into the design and preparation of GDY-based devices and broaden the application fields of GDY.

2.
Inorg Chem ; 61(9): 4150-4158, 2022 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-35200007

RESUMO

The rational synthesis of iron-sulfur clusters with excellent control of the core ligands has been a significant challenge in biomimetic chemistry. In this work, the rational construction of versatile Mo-Fe-S cubane clusters was realized using a LEGO strategy. (LEGO is a line of plastic construction toys consisting of various interlocking plastic bricks which can be assembled and connected in different ways to construct versatile objects. Herein we use "LEGO strategy" as an analogy for the stepwise synthetic methodology, and we use "brick" to represent a corner atom of the cubane structure.) Through careful synthetic control, the ⟨Fe⟩, ⟨S⟩, and ⟨Cl⟩ bricks were mounted piece-by-piece onto the basic ⟨MoS3⟩ frame to stepwise construct the incomplete cubane core ⟨MoFe2S3Cl⟩ and the complete cubane core ⟨MoFe3S3Cl⟩. The significantly elongated Fe-Cl bonds for the bridging chlorides in the ⟨MoFe2S3Cl⟩ and ⟨MoFe3S3Cl⟩ cores permit ligand metatheses to introduce 2p donors at the bridging sites, which used to be a challenge in traditional iron-sulfur chemistry. Therefore, in subsequent controlled reactions, the bridging ⟨Cl⟩ bricks of the ⟨MoFe2S3Cl⟩ and ⟨MoFe3S3Cl⟩ frames could be easily replaced by ⟨N⟩ , ⟨O⟩, or ⟨S⟩ bricks to generate the ⟨MoFe2S3N⟩, ⟨MoFe2S3O⟩, ⟨MoFe3S3N⟩, and ⟨MoFe3S4⟩ cluster cores, demonstrating more choices for the LEGO synthetic strategy. The series of Mo-Fe-S clusters and their derivatives, together with related synthetic strategies, offers a good platform and methodology for biomimetic chemistry in relation to nitrogenase, especially the FeMo cofactor.

3.
Hepatobiliary Pancreat Dis Int ; 21(4): 325-333, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34674948

RESUMO

BACKGROUND: Macrovascular invasion (MaVI) occurs in nearly half of hepatocellular carcinoma (HCC) patients at diagnosis or during follow-up, which causes severe disease deterioration, and limits the possibility of surgical approaches. This study aimed to investigate whether computed tomography (CT)-based radiomics analysis could help predict development of MaVI in HCC. METHODS: A cohort of 226 patients diagnosed with HCC was enrolled from 5 hospitals with complete MaVI and prognosis follow-ups. CT-based radiomics signature was built via multi-strategy machine learning methods. Afterwards, MaVI-related clinical factors and radiomics signature were integrated to construct the final prediction model (CRIM, clinical-radiomics integrated model) via random forest modeling. Cox-regression analysis was used to select independent risk factors to predict the time of MaVI development. Kaplan-Meier analysis was conducted to stratify patients according to the time of MaVI development, progression-free survival (PFS), and overall survival (OS) based on the selected risk factors. RESULTS: The radiomics signature showed significant improvement for MaVI prediction compared with conventional clinical/radiological predictors (P < 0.001). CRIM could predict MaVI with satisfactory areas under the curve (AUC) of 0.986 and 0.979 in the training (n = 154) and external validation (n = 72) datasets, respectively. CRIM presented with excellent generalization with AUC of 0.956, 1.000, and 1.000 in each external cohort that accepted disparate CT scanning protocol/manufactory. Peel9_fos_InterquartileRange [hazard ratio (HR) = 1.98; P < 0.001] was selected as the independent risk factor. The cox-regression model successfully stratified patients into the high-risk and low-risk groups regarding the time of MaVI development (P < 0.001), PFS (P < 0.001) and OS (P = 0.002). CONCLUSIONS: The CT-based quantitative radiomics analysis could enable high accuracy prediction of subsequent MaVI development in HCC with prognostic implications.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/cirurgia , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/cirurgia , Prognóstico , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos
4.
Proc Natl Acad Sci U S A ; 115(20): 5089-5092, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29654147

RESUMO

Molybdenum-dependent nitrogenases catalyze the transformation of dinitrogen into ammonia under ambient conditions. The active site (FeMo cofactor) is the structurally and electronically complex weak-field metal cluster [MoFe7S9C] built of Fe4S3 and MoFe3S3C portions connected by three sulfur bridges and containing an interstitial carbon atom centered in an Fe6 trigonal prism. Chemical synthesis of this cluster is a major challenge in biomimetic inorganic chemistry. One synthetic approach of core ligand metathesis has been developed based on the design and synthesis of unprecedented incomplete ([(Tp*)WFe2S3Q3]-) and complete ([(Tp*)WFe3S3Q4]2-) cubane-type clusters containing bridging halide (Q = halide). These clusters are achieved by template-assisted assembly in the presence of sodium benzophenone ketyl reductant; products are controlled by reaction stoichiometry. Incomplete cubane clusters are subject to a variety of metathesis reactions resulting in substitution of a µ2-bridging ligand with other bridges such as N3-, MeO-, and EtS- Reactions of complete cubanes with Me3SiN3 and S8 undergo a redox metathesis process and lead to core ligand displacement and formation of [(Tp*)WFe3S3(µ3-Q)Cl3]- (Q = Me3SiN2-, S2-). This work affords entry to a wide variety of heteroleptic clusters derivable from incomplete and complete cubanes; examples are provided. Among these is the cluster [(Tp*)WFe3S3(µ3-NSiMe3)Cl3]-, one of the very few instances of a synthetic Fe-S cluster containing a light atom (C, N, O) in the core, which constitutes a close mimic of the [MoFe3S3C] fragment in FeMo cofactor. Superposition of them and comparison of metric information disclose a clear structural relationship [Tp* = tris(3,5-dimethyl-1-pyrazolyl)hydroborate(1-)].


Assuntos
Complexos de Coordenação/química , Molibdênio/química , Molibdoferredoxina/química , Enxofre/química , Catálise , Domínio Catalítico , Cristalografia por Raios X , Proteínas Ferro-Enxofre/química , Proteínas Ferro-Enxofre/metabolismo , Ligantes , Modelos Moleculares , Estrutura Molecular , Nitrogenase/química , Nitrogenase/metabolismo , Oxirredução
5.
Surg Innov ; 28(4): 419-426, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33275087

RESUMO

Introduction. Complex anal fistula (CAF) is a challenging anorectal condition. Although numerous treatments for its management have been proposed, none is ideal. Herein, we investigated the clinical efficacy of video-assisted modified ligation of the intersphincteric fistula tract (LIFT) in comparison with the incision-thread-drawing procedure for Parks type II anal fistulas. Methods. Male and female adult patients with Parks type II anal fistula who were randomized to receive one of two procedures in the Anorectal Surgery Unit of the Affiliated People's Hospital of Ningbo University: video-assisted modified LIFT (test group, 30 cases) or incision thread drawing (control group, 30 cases). Healing and recurrence, postoperative pain, and postoperative autonomous anal control ability were compared. Results. In the test group, the pain scores were significantly lower (P = .001) and wound healing was faster (P = .001). However, there were no marked differences between groups in operative efficacy or postoperative infection rate (all P > .05). We followed all the patients for more than 18 months, with the test group having lower Jorge-Wexner incontinence (P = .005) and fecal incontinence (FI) severity index (P = .000) scores. No significant difference in recurrence (χ2 = .351, P = .554) or healing (χ2 = 1.071, P = .301) rate was found between the 2 groups. Conclusions. We established that video-assisted modified LIFT is superior in repairing Parks type II anal fistulas, with less trauma, quicker recovery, and better anal function.


Assuntos
Incontinência Fecal , Fístula Retal , Adulto , Canal Anal , Feminino , Humanos , Ligadura , Masculino , Fístula Retal/cirurgia , Recidiva , Resultado do Tratamento
6.
Crit Rev Eukaryot Gene Expr ; 30(3): 253-264, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32749112

RESUMO

This article serves to evaluate the association of polymorphisms of mismatch repair genes (hMLH1 and hMSH2) with breast cancer (BC) susceptibility through a meta-analysis. Our methods involved extensive research in Chinese and English databases that examined the association of hMLH1 and hMSH2 polymorphisms with susceptibility to BC, strictly abiding by established inclusion and exclusion criteria. Software Stata 12.0 was used for statistical data analysis. A total of 12 studies were available for meta-analysis, published between 2014 and 2017, of which respectively 9 studies explored the association of hMLH1 (rs1799977 A > G and rs63750447 T > A) and 3 studies explored the association of hMSH2 (rs4987188 [Gly322Asp] and rs17217772 [Asn127Ser]) with patients' susceptibility to BC. The results showed that both the rs1799977 A > G polymorphism GA + GG genotype (especially in the Caucasian population) and the rs63750447 T > A polymorphism TA + AA genotype in the hMLH1 gene increased patients' susceptibility to BC. The genotype detection method was selected as a target for subgroup analysis. According to studies where MassARRAY assay was conducted, the rs1799977 A > G polymorphism was correlated with BC susceptibility in the dominant model, while rs4987188 (Gly322Asp) and rs17217772 (Asn127Ser) of the hMSH2 gene presented no observable correlation with the risk for BC. Both the rs1799977 A > G and rs63750447 T > A polymorphisms in the hMLH1 gene showed a significant association with a markedly increased risk for BC, while rs4987188 (Gly322Asp) and rs17217772 (Asn127Ser) of the hMSH2 gene were not clearly correlated with BC susceptibility.


Assuntos
Neoplasias da Mama/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Reparo de Erro de Pareamento de DNA , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Adulto Jovem
7.
Small ; 16(50): e2003593, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33230902

RESUMO

Achieving multifunctional van der Waals nanoelectronic devices on one structure is essential for the integration of 2D materials; however, it involves complex architectural designs and manufacturing processes. Herein, a facile, fast, and versatile laser direct write micro/nanoprocessing to fabricate diode, NPN (PNP) bipolar junction transistor (BJT) simultaneously based on a pre-fabricated black phosphorus/molybdenum disulfide heterostructure is demonstrated. The PN junctions exhibit good diode rectification behavior. Due to different carrier concentrations of BP and MoS2 , the NPN BJT, with a narrower base width, renders better performance than the PNP BJT. Furthermore, the current gain can be modulated efficiently through laser writing tunable base width WB , which is consistent with the theoretical results. The maximum gain for NPN and PNP is found to be ≈41 (@WB ≈600 nm) and ≈12 (@WB ≈600 nm), respectively. In addition, this laser write processing technique also can be utilized to realize multifunctional WSe2 /MoS2 heterostructure device. The current work demonstrates a novel, cost-effective, and universal method to fabricate multifunctional nanoelectronic devices. The proposed approach exhibits promise for large-scale integrated circuits based on 2D heterostructures.

8.
Inorg Chem ; 59(1): 254-263, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31762286

RESUMO

Visible-light driven photoreactions using metal-organic frameworks (MOFs) as catalysts are promising with regard to their environmental friendly features such as the use of renewable and sustainable energy of visible light and potential catalyst recyclability. To develop potential heterogeneous photocatalysts, a family of three copper(II) coordination polymers bearing different Cu-O assemblies have been synthesized with the ligand 4,4'-disulfo-[1,1'-biphenyl]-2,2'-dicarboxylate acid (H4DSDC), namely, {[Cu7(DSDC)2(OH)6(H2O)10]·xH2O}n (1), {[Cu4(DSDC)(4,4'-bpy)2(OH)4]·2H2O}n (2), and {Cu2(DSDC)(phen)2(H2O)2}n (3) (4,4'-bpy = 4,4'-bipyridine and phen = 1,10-phenanthroline). Complex 1 represents a metal-organic framework featuring a NbO type topology constructed from the infinite linkage of heptanuclear [Cu7(µ3-OH)6(H2O)10]8+ clusters by deprotonated DSDC4- ligands, comprising one-dimensional hexagonal channels of a diameter around 11 Å that are filled with water molecules. The infinite waving {[Cu2(OH)2]2+}n ladderlike chains in complex 2 are bridged by DSDC4- and 4,4'-bpy ligands into a three-dimensional framework. A two-dimensional layered structure is formed in complex 3 due to the existence of terminal phenanthroline ligands. All of the coordination polymers 1-3 are able to catalyze the visible-light driven oxidation of alcohols at mild conditions using hydrogen peroxide as an oxidant, in which complex 1 demonstrates satisfactory efficiency. Significantly for this photoreaction catalyzed by 1, the extent of oxidation over aryl primary alcohols is fully controllable with time-resolved product selectivity, giving either corresponding aldehydes or carboxylate acids in good yields. It is also remarkable that the photocatalyst could be recovered almost quantitatively on completion of the catalytic cycle without any structure change, and could be recycled for catalytic use for at least five cycles with constant efficiency. This photocatalyst with time-resolved selectivity for different products may provide new insight into the design and development of novel catalytic systems.

9.
Med Sci Monit ; 26: e920682, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32187175

RESUMO

BACKGROUND TaohongSiwu decoction (THSWT), a traditional herbal formula, has been used to treat cardiovascular and cerebrovascular diseases such as essential hypertension (EH) in China. However, the pharmacological mechanism is not clear. To investigate the mechanisms of THSWT in the treatment of EH, we performed compounds, targets prediction and network analysis using a network pharmacology method. MATERIAL AND METHODS We selected chemical constituents and targets of THSWT according to TCMSP and UniProtKB databases and collected therapeutic targets on EH from Online Mendelian Inheritance in Man (OMIM), Drugbank and DisGeNET databases. The protein-protein interaction (PPI) was analyzed by using String database. Then network was constructed by using Cytoscape_v3.7.1, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment was performed by using Database for Annotation, Visualization and Integrated Discovery (DAVID) software. RESULTS The results of our network pharmacology research showed that the THSWT, composed of 6 Chinese herbs, contained 15 compounds, and 23 genes regulated the main signaling pathways related to EH. Moreover, the PPI network based on targets of THSWT on EH revealed the interaction relationship between targets. These core compounds were 6 of the 15 disease-related compounds in the network, kaempferol, quercetin, luteolin, Myricanone, beta-sitosterol, baicalein, and the core genes contained ADRB2, CALM1, HMOX1, JUN, PPARG, and VEGFA, which were regulated by more than 3 compounds and significantly associated with Calcium signaling pathway, cGMP-PKG signaling pathway, cAMP signaling pathway, PI3K-Akt signaling pathway, Rap1 signaling pathway, and Ras signaling pathway. CONCLUSIONS This network pharmacological study can reveal potential mechanisms of multi-target and multi-component THSWT in the treatment of EH, provide a scientific basis for studying the mechanism.


Assuntos
Medicamentos de Ervas Chinesas/uso terapêutico , Hipertensão Essencial/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , China , Bases de Dados Genéticas , Humanos , Mapas de Interação de Proteínas , Resultado do Tratamento
10.
Angew Chem Int Ed Engl ; 58(46): 16469-16473, 2019 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-31489739

RESUMO

Incorporation of monatomic 2p ligands into the core of iron-sulfur clusters has been researched since the discovery of interstitial carbide in the FeMo cofactor of Mo-dependent nitrogenase, but has proven to be a synthetic challenge. Herein, two distinct synthetic pathways are rationalized to install nitride ligands into targeted positions of W-Fe-S clusters, generating unprecedented nitride-ligated iron-sulfur clusters, namely [(Tp*)2 W2 Fe6 (µ4 -N)2 S6 L4 ]2- (Tp*=tris(3,5-dimethyl-1-pyrazolyl)hydroborate(1-), L=Cl- or Br- ). 57 Fe Mössbauer study discloses metal oxidation states of WIV2 FeII4 FeIII2 with localized electron distribution, which is analogous to the mid-valent iron centres of FeMo cofactor at resting state. Good agreement of Mössbauer data with the empirical linear relationship for Fe-S clusters indicates similar ligand behaviour of nitride and sulfide in such clusters, providing useful reference for reduced nitrogen in a nitrogenase-like environment.


Assuntos
Ferro/química , Nitrogênio/química , Enxofre/química , Tungstênio/química , Cristalografia por Raios X , Ligantes , Conformação Molecular , Oxirredução , Pirazóis/química , Espectroscopia de Mossbauer
11.
Macromol Rapid Commun ; 39(12): e1700714, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29749065

RESUMO

Development of two-way shape memory polymers that operate free of external force remains a great challenge. Here, the design criteria for this type of material are proposed, deriving a novel fabrication strategy accordingly, which employs conventional crosslinked polyurethane (PU) containing crystalline poly(ε-caprolactone) (PCL) as the proof-of-concept material. Having been simply trained by stretching and thermal treatment without additional ingredients and chemicals, the PU is coupled with a two-way shape memory effect. The core advancement of this study lies in the successful conversion of the inherent hydrogen bond network, which is often the easiest to overlook, into an internal stress provider. The temperature-dependent reversible melting/recrystallization of the crystalline phases elaborately works with the tensed hydrogen bond network, leading to implementation of the two-way shape memory effect. An average reversible strain of as high as ≈20% along the stretch direction is obtained through cooperation adjustment of chemical crosslinking density, crystallinity, and concentration of hydrogen bonds. Meanwhile, the highest internal tension offered by the hydrogen bond network is determined to be 0.10 MPa. Owing to the great convenience characterized by material selection, preparation, programming, and application, the current work may open up an avenue for production and usage of the smart material.


Assuntos
Materiais Biocompatíveis/química , Poliésteres/química , Polímeros/química , Poliuretanos/química , Materiais Biocompatíveis/síntese química , Cristalização , Ligação de Hidrogênio , Estrutura Molecular , Polímeros/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
12.
Sheng Li Xue Bao ; 70(4): 391-396, 2018 Aug 25.
Artigo em Zh | MEDLINE | ID: mdl-30112564

RESUMO

The purpose of the study was to investigate the effect of sophoridine on the proliferation and apoptosis of human gastric cancer MKN45 cells and the possible mechanism. MKN45 cells were randomly divided into control and sophoridine (including 6 subgroups) groups. Cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) colorimetric method. The protein expression of high mobility group-box 3 (HMGB3) was observed by immunocytochemical staining and Western blot. Hoechst 33342 staining method was used to observe the morphological changes of cells treated with sophoridine. Apoptosis was detected by flow cytometry. The results showed that the proliferation of cells was inhibited by 48-hour treatment of sophoridine in a dose-dependent manner. Compared with control group, sophoridine group showed decreased HMGB3 protein expression and increased apoptotic rate. These results suggest that sophoridine can inhibit the proliferation of MKN45 cells and promote their apoptosis, which may be related to down-regulation of HMGB3 protein expression.


Assuntos
Alcaloides/farmacologia , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quinolizinas/farmacologia , Neoplasias Gástricas/patologia , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Proteína HMGB3/metabolismo , Humanos , Matrinas
13.
Macromol Rapid Commun ; 38(16)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28627040

RESUMO

The present communication reports a novel strategy to fabricate reversible shape-memory polymer that operates without the aid of external force on the basis of a two-phase structure design. The proof-of-concept material, crosslinked styrene-butadiene-styrene block copolymer (SBS, dispersed phase)/polycaprolactone-based polyurethane (PU, continuous phase) blend, possesses a closely connected microphase separation structure. That is, SBS phases are chemically bonded to crosslinked PU by means of a single crosslinking agent and two-step crosslinking process for increasing integrity of the system. Miscibility between components in the blend is no longer critical by taking advantage of the reactive blending technique. It is found that a suitable programming leads to compressed SBS, which serves as internal expansion stress provider as a result. The desired two-way shape-memory effect is realized by the joint action of the temperature-induced reversible opposite directional deformabilities of the crystalline phase of PU and compressed SBS, accompanying melting and orientated recrystallization of the former. Owing to the broadness of material selection and manufacturing convenience, the proposed approach opens an avenue toward mass production and application of the smart polymer.


Assuntos
Técnicas de Química Analítica , Polímeros/síntese química , Elastômeros , Fenômenos Mecânicos , Poliuretanos/química , Estirenos/química , Temperatura
14.
Angew Chem Int Ed Engl ; 56(14): 3852-3856, 2017 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-28247533

RESUMO

The photoinduced regio- and enantioselective coupling of naphthols and derivatives thereof is achieved in the confined chiral coordination space of a RuII metalloligand based cage. The racemic or enantiopure cages encapsulate naphthol guests, which then undergo a regiospecific 1,4-coupling, rather than the normal 1,1-coupling, to form 4-(2-hydroxy-1-naphthyl)-1,2-napthoquinones; moderate stereochemical control is achieved with homochiral cages. The photoreactions proceed under both aerobic and anaerobic conditions but through distinct pathways that nevertheless involve the same radical intermediates. This unusual dimerization constitutes a very rare example of asymmetric induction in biaryl coupling by making use of coordination cages with dual functionality-photoredox reactivity and stereoselectivity.

15.
Nanotechnology ; 27(9): 095301, 2016 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-26822121

RESUMO

Graphene has been extensively investigated for its use in flexible electronics, especially graphene synthesized by chemical vapor deposition (CVD). To enhance the flexibility of CVD graphene, wrinkles are often introduced. However, reports on the flexibility of reduced graphene oxide (RGO) films are few, because of their weak conductivity and, in particular, poor flexibility. To improve the flexibility of RGO, reduced graphene oxide nanoshells are fabricated, which combine self-assembled polystyrene nanosphere arrays and high-temperature thermal annealing processes. The resulting RGO films with nanoshells present a better resistance stabilization after stretching and bending the devices than RGO without nanoshells. The sustainability and performance advances demonstrated here are promising for the adoption of flexible electronics in a wide variety of future applications.

16.
Opt Express ; 23(19): 24177-88, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26406624

RESUMO

The polarization dependence of transient optical reflection, induced by nonequilibrium carriers isotropically distributed in momentum space, of graphene on substrate is experimentally and theoretically investigated. It is found that this transient optical reflection could be made greatly polarization dependent by using oblique incidence for light, and the characteristic of this polarization dependence could be flexibly altered with incident angle and incident direction (from graphene to substrate, or from substrate to graphene). Our results suggest that through polarization of incident beam is an efficient way of manipulating graphene transient optical reflection.

17.
J Vasc Surg ; 61(6): 1424-31, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25702918

RESUMO

OBJECTIVE: We report our experience of endovascular management and postoperative aortic remodeling of all types of isolated abdominal aortic dissection (IAAD). METHODS: This was retrospective study of 28 IAAD patients treated by endovascular means in our department between January 2007 and July 2013. We reviewed the risk factors, clinical features, computed tomography images, follow-up results, and aortic remodeling of these IAAD patients and propose a new morphologic classification into three types-supraceliac, paravisceral, and infrarenal-according to the location of the primary entry site. RESULTS: There were four supraceliac IAADs, one paravisceral IAAD, and 23 infrarenal IAADs in our case series. Suprarenal (supraceliac + paravisceral) IAAD patients were relatively younger than infrarenal patients (45.2 ± 8.6 years vs 60.6 ± 15.5 years; P < .05). No difference was observed between suprarenal and infrarenal IAADs with respect to true lumen, false lumen, and dissection length on imaging (P > .05). All patients received endovascular treatment. The primary technical success rate was 100%. During a follow-up of 35.7 ± 19.9 months, only one infrarenal patient needed an endovascular reintervention. All patients with supraceliac or infrarenal IAADs were alive at the time of follow-up; however, a paravisceral patient died of a dissecting abdominal aortic aneurysm rupture 21 months after endovascular treatment. In the suprarenal and infrarenal groups, endovascular treatment was associated with a significant decrease in the false lumen size and increase in the true lumen size (P < .05). The maximum abdominal aorta diameter decreased after endovascular treatment in both groups but was statistically significant only in the infrarenal group (P < .05). CONCLUSIONS: IAAD is a rare vascular disease. We propose it should be categorized as supraceliac, paravisceral, and infrarenal IAAD according to the location of the primary entry site. Endovascular treatment for supraceliac and infrarenal IAADs is a safe method with a high technical success rate and promising aortic remodeling, whereas endovascular treatment for paravisceral IAADs remains difficult.


Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Dissecção Aórtica/cirurgia , Implante de Prótese Vascular , Procedimentos Endovasculares , Remodelação Vascular , Adulto , Idoso , Dissecção Aórtica/diagnóstico , Dissecção Aórtica/mortalidade , Dissecção Aórtica/fisiopatologia , Aneurisma da Aorta Abdominal/diagnóstico , Aneurisma da Aorta Abdominal/mortalidade , Aneurisma da Aorta Abdominal/fisiopatologia , Aortografia/métodos , Implante de Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/mortalidade , China , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento
18.
J Vasc Surg ; 59(1): 165-72, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23992995

RESUMO

OBJECTIVE: To explore a therapy strategy for the spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) based on morphologic classification. METHODS: Forty-two symptomatic patients with SIDSMA presenting with abdominal pain between January 2007 and December 2012 were enrolled in this retrospective study. We proposed a new morphologic classification with subtypes depending on the patency of the true lumen and reviewed the patients' clinical features, risk factors, computed tomography images (morphologic classification, location of entry site, dissection length, and true lumen residual diameter), treatment modalities, and follow-up results. RESULTS: Twenty-four patients received only observation treatment, seven received open surgery, and 11 received endovascular therapy. True lumen residual diameter in the observation group (46.6%) was statistically better than that in the surgery group (0%) and the endovascular group (18.3%) (P < .05). There was clinical progression in three and imaging progression in seven of the observation group, of which two patients received endovascular treatment and one patient died of bowel infarction. There were two clinical progressions and one imaging progression in the surgery group, of which two patients received additional surgery and one patient died of bowel infarction. The endovascular group obtained encouraging results with no progressions or complications. CONCLUSIONS: Symptomatic patients with SIDSMA are at risk of progression. We suggested a morphologic classification to guide the treatment. We recommend observation treatment with close follow-up for patients with patent true lumen flow and endovascular intervention for high-risk patients with true lumen stenosis or occlusion. Surgery is indicated for patients with suspected bowel infarction or arterial rupture.


Assuntos
Dissecção Aórtica/classificação , Dissecção Aórtica/terapia , Procedimentos Endovasculares , Artéria Mesentérica Superior/cirurgia , Procedimentos Cirúrgicos Vasculares , Conduta Expectante , Dor Abdominal/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Dissecção Aórtica/complicações , Dissecção Aórtica/diagnóstico por imagem , Dissecção Aórtica/mortalidade , Dissecção Aórtica/cirurgia , Distribuição de Qui-Quadrado , Progressão da Doença , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/mortalidade , Feminino , Humanos , Masculino , Artéria Mesentérica Superior/diagnóstico por imagem , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares/efeitos adversos , Procedimentos Cirúrgicos Vasculares/mortalidade
19.
Opt Lett ; 39(19): 5574-7, 2014 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25360931

RESUMO

A giant Goos-Hänchen (G-H) shift in graphene has been theoretically predicted by previous research. In this Letter, we present experimental measurements of the G-H shift in graphene, in a total internal reflection condition, using a new method we have named "the beam splitter scanning method." Our results show that a focused light source undergoes significant lateral shift when the polarization of incident light changes from transverse magnetic (TM) to transverse electric (TE) mode, indicating a large G-H shift in graphene that is polarization-dependent. We also observed that the difference in the G-H shift for TM versus TE modes (S(TM)-S(TE)) increases with increasing thickness of graphene material. A maximum difference (S(TM)-S(TE)) of 31.16 µm was observed, which is a significant result. Based on this research, the ability to engineer giant G-H shifts in graphene material has now been experimentally confirmed for the first time to the best of our knowledge. We expect that this result will lead to significant new and interesting applications of graphene in various types of optical sensors, and more.

20.
Nanotechnology ; 25(45): 455707, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25338947

RESUMO

We have developed a method to tune polarization-dependent optical absorption of large-scale chemical vapor deposition (CVD) graphene under total internal reflection (TIR) by strain engineering. Through control of the strain direction, the optical absorption of graphene for transverse magnetic or transverse electric waves can be separately tuned. Strain-induced modulation of the optical absorption has been theoretically expected when light is normally incident through graphene. Under TIR, however, we experimentally observed a significant increase in the strain-induced tunability of optical absorption for CVD graphene, with the modulation efficiency of optical absorption in monolayer graphene increasing by a factor of three times that for normal incidence. We conclude that the strain sensitivity of optical absorption of graphene under TIR offers significant potential for application in many areas such as ultra-thin optical devices and strain sensors.

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