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1.
Opt Lett ; 46(17): 4336, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34470007

RESUMO

This publisher's note contains a correction to Opt. Lett.45, 6635 (2020)OPLEDP0146-959210.1364/OL.409690.

2.
Opt Lett ; 45(24): 6635-6638, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33325857

RESUMO

We propose and numerically demonstrate that the phenomena of coherent perfect absorption, invisibility, and lasing can be simultaneously realized in a composite structure with both lossy and gain components. The three distinct functions can be independently triggered by incident waves with different orbital angular momenta. For instance, a triple-layer cylinder is demonstrated to simultaneously achieve perfect absorption, invisibility, and lasing under cylindrical monopolar, dipolar, and quadrupolar incidence, respectively. This Letter demonstrates that total attenuation, elimination of scattering, and great amplification can all be constructed in a single non-Hermitian photonic device, which utilizes the orbital angular momentum as a controlling mechanism for customized functions.

3.
Br J Neurosurg ; : 1-5, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-33016150

RESUMO

OBJECTIVE: To explore the clinical significance of dynamic monitoring of cerebrospinal fluid (CSF) and serum Lactic acid(Lac), neuron-specific enolase (NSE), and the blood-brain barrier (BBB) index in evaluating the condition and prognosis after a severe traumatic brain injury (TBI). METHODS: A total of 52 severe TBI patients admitted to the Department of Neurosurgery within 24 hours after injury were dynamically monitored. CSF and serum samples were collected on the 1st, 3rd, and 7th day after a severe TBI to monitor the changes in Lac, NSE, and the BBB index. Intracranial pressure (ICP), Glasgow coma scale (GCS), and 6-month Glasgow outcome scale-extended (GOS-E) were tested. According to the results of GOS-E, the patients were divided into two groups (i.e. the poor prognosis group and good prognosis group). Statistical analysis was conducted to investigate the clinical significance of dynamic monitoring of CSF and serum Lac, NSE, and BBB index after a severe TBI. RESULTS: After a severe TBI, the levels of Lac, NSE, and BBB in CSF and serum were significantly higher than those in the normal range. Lac, NSE, and the BBB index did not correlate with ICP (except serum Lac) but had correlations with GCS and post-injury 6 months post-injury (except serum Lac). Moreover, the correlations between Lac, NSE, and BBB index were statistically significant (p < 0.05): CSF Lac and CSF NSE; CSF Lac and serum NSE; Lac and BBB index of CSF; Lac and BBB index of CSF; NSE and CSE of serum; CSF NSE and BBB index; and serum NSE and BBB index. Additionally, serum NSE is correlated with NSE in CSF (p < 0.05). CONCLUSION: After a severe TBI, dynamic monitoring of CSF and serum Lac, NSE, and BBB index has the potential to assess the condition, predict the prognosis, and have clinical significance.

4.
Phys Rev Lett ; 117(22): 223901, 2016 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-27925741

RESUMO

By using pure dielectric photonic crystals, we demonstrate the realization of ultratransparent media, which allow near 100% transmission of light for all incident angles and create aberration-free virtual images. The ultratransparency effect is well explained by spatially dispersive effective medium theory for photonic crystals, and verified by both simulations and proof-of-principle microwave experiments. Designed with shifted elliptical equal frequency contours, such ultratransparent media not only provide a low-loss and feasible platform for transformation optics devices at optical frequencies, but also enable new freedom for phase manipulation beyond the local medium framework.

5.
Ren Fail ; 37(5): 751-6, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25707513

RESUMO

AIM: The investigations into the association between the receptor for advanced glycation end products (RAGE) gene -374T/A, -429T/C polymorphisms and diabetic nephropathy (DN) in several case-control studies have rendered conflicting results. To shed light on these inconclusive findings, a meta-analysis of all the eligible studies relating these two polymorphisms to the risk of DN was conducted. METHODS: The databases were searched for relevant articles up to July 2014. A pooled estimate of the genetic association, the heterogeneity between studies, and the publication bias were investigated. RESULTS: Eight studies with 1725 cases and 1857 controls were enrolled in -374T/A polymorphism analysis. The main analysis indicated no association for the allele contrast, the recessive model and the dominant model. Subgroup analyses in Caucasians and in type 2 diabetes also showed no association between -374T/A polymorphism and DN. Five studies with 1019 cases and 792 controls were enrolled in -429T/C polymorphism analysis. The main analysis revealed heterogeneity and no association for the allele contrast and the dominant model. However, the recessive model for -429C allele diminished the heterogeneity and showed a marginal association overall [fixed-effects OR = 2.83 (1.33-6.00) and random effects OR = 2.50 (1.00-6.24), respectively]. CONCLUSIONS: Our meta-analysis indicated that the RAGE gene -429CC genotype might be a risk factor for DN in patients with type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2/genética , Nefropatias Diabéticas/genética , Receptor para Produtos Finais de Glicação Avançada/genética , Alelos , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único , Fatores de Risco
6.
Phys Rev Lett ; 112(7): 073903, 2014 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-24579601

RESUMO

We propose a method to control electromagnetic flux in an almost arbitrary way in wavelength and subwavelength scales. The capability of subwavelength flux control is enabled by the evanescent waves induced in a class of inhomogeneous anisotropic media with a near-zero permittivity component. By designing the spatial profile of the other permittivity component in such inhomogeneous media, the flow and distribution of energy flux can be conveniently manipulated. This method provides another approach to efficiently control electromagnetic flux in nonmagnetic media.

7.
J Burn Care Res ; 44(4): 832-836, 2023 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-36181672

RESUMO

This paper explores the effectiveness of virtual reality in reducing pain in school-aged children undergoing burn wound care. From June 2020 to September 2021, 34 cases of burned children treated in the burn clinic of a hospital were selected. A before- and after-study design was utilized to observe the first and second wound dressing changes of the same patients. The two dressing changes were randomly selected for the VR plan and the Non-VR plan. In VR Plan, patients played virtual reality games using a headset and gamepad to distract from their pain. To determine the effectiveness of VR, the children's pain score, heart rate, blood oxygen saturation, and adverse reactions such as dizziness and nausea were recorded ten minutes before wound dressing change, during wound dressing change and ten minutes after the bandages was on. The Wong-Baker and FLACC scores of the patients in the VR group were (5.79 ± 1.84) and (4.91 ± 2.08), respectively, whereas the scores of the patients in the non-VR group were (5.47 ± 1.99) and (4.91 ± 2.25), respectively, 10 minutes before wound dressing changes. During wound dressing changes, the Wong-Baker and FLACC scores of patients in the VR group were (3.78 ± 1.49) and (2.73 ± 1.38), respectively, whereas the scores of patients in the non-VR group were (5.58 ± 2.48) and (4.97 ± 2.39), respectively. After wound dressing changes, the Wong-Baker and FLACC scores of patients in the VR group were (2.44 ± 1.65) and (2.12 ± 1.34), respectively, and the scores of patients in the non-VR group were (4.21 ± 2.42) and (3.75 ± 2.05), respectively. The study concludes that virtual reality is effective in reducing pain in school-aged children with burn wounds. The study also concludes that virtual reality does not cause adverse reactions.


Assuntos
Queimaduras , Realidade Virtual , Humanos , Criança , Manejo da Dor/efeitos adversos , Queimaduras/complicações , Queimaduras/terapia , Medição da Dor , Dor/etiologia
8.
J Biomed Biotechnol ; 2012: 373945, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23091345

RESUMO

Toll-like receptors (TLRs) are pivotal components of the innate immune response. Activation of the innate immune system and subsequent chronic low-grade inflammation are thought to be involved in the pathogenesis of atherosclerosis and type 2 diabetes. In the study, we genotyped TLRs gene polymorphisms, including TLR2 Arg677Trp and Arg753Gln, TLR4 Asp299Gly and Thr399Ile, TLR9-1486T/C and -1237T/C. The frequencies of TT, TC and CC genotype of TLR9-1486T/C mutation were 39.6%, 45.8% and 14.6%, respectively; the frequencies of T allele and C allele were 62.5% and 37.5%. However, neither of these parameters was statistically significant among study groups. In addition, we were surprised to find that the commonly reported TLR SNPs in the Western countries, like TLR2 Arg677Trp or Arg753Gln, TLR4 Asp299Gly or Thr399Ile and TLR9-1237T/C, were not polymorphic at all in all study subjects. In conclusion, our data suggests that TLR2 Arg677Trp or Arg753Gln, TLR4 Asp299Gly or Thr399Ile and TLR9-1237T/C polymorphisms have low frequency and TLR9-1486T/C polymorphism may not be a suitable marker in predicting the susceptibility to type 2 diabetes or coronary artery disease in the Chinese Han population.


Assuntos
Doença da Artéria Coronariana/epidemiologia , Doença da Artéria Coronariana/genética , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença/genética , Polimorfismo de Nucleotídeo Único/genética , Receptores Toll-Like/genética , Idoso , China/epidemiologia , Comorbidade , Feminino , Frequência do Gene/genética , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fatores de Risco
9.
Int J Gynaecol Obstet ; 156(1): 139-144, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33715162

RESUMO

OBJECTIVE: To explore the ability of albumin concentration to predict calf venous thromboembolism (cVTE) in gynecologic diseases. METHODS: We analyzed data from 761 patients from the gynecology department. We screened the serum albumin concentration as an important indicator for predicting cVTE through logistic analysis. The data were divided into albumin below 35 and 35 g/L or more. Receiver operating characteristics analysis was used to compare the predictive ability of albumin, D-dimer, and a combination of these parameters as indicators for cVTE risk in different groups and subgroups. RESULTS: In gynecologic diseases, the albumin concentrations were lower in the surgery and malignancy group than in the chemotherapy and benign disease group. Albumin concentration had a predictive ability for cVTE risk. In ovarian cancer patients with albumin concentrations less than 35 g/L, albumin was better than D-dimer at predicting cVTE (area under the curve [AUC] 0.79, 95% confidence interval [CI] 0.70-0.87, P < 0.001 versus AUC 0.65, 95% CI 0.54-0.77, P = 0.016). CONCLUSION: The albumin concentration was a candidate indicator for predicting cVTE in surgical patients in the gynecology department, especially in ovarian cancer patients with albumin concentrations less than 35 g/L. A combination of the albumin and D-dimer parameters may improve the predictive ability for cVTE.


Assuntos
Tromboembolia Venosa , Albuminas , Feminino , Procedimentos Cirúrgicos em Ginecologia/efeitos adversos , Humanos , Curva ROC , Fatores de Risco , Tromboembolia Venosa/diagnóstico , Tromboembolia Venosa/epidemiologia , Tromboembolia Venosa/etiologia
10.
Front Cardiovasc Med ; 9: 1101929, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36684563

RESUMO

A 10-year-old girl presented with obvious cyanosis, and the saturation of arterial blood oxygen (SpO2) was decreased to 60.5% in the outpatient examination. Computed tomography angiography (CTA) and echocardiography suggested congenitally corrected transposition of the great arteries (ccTGAs), membranous ventricular septal aneurysm (MVSA), atrial septal defect (ASD), severe pulmonary stenosis (PS), and severe tricuspid regurgitation (TR). Due to the complex pathological anatomical structures, the three-dimensional printed model was used for preoperative assessment. After a comprehensive evaluation was completed, the operation was performed by physiological correction under cardiopulmonary bypass, including the resection of MVSA, repair using the bovine pericardial patch for ASD, and linear valvuloplasty of the tricuspid valve. Due to the special anatomical structures of ccTGA, PS was treated by extracardiac pipe technique. After the operation, the patient recovered well, cyanosis disappeared, SpO2 was up to 96%, and the extracardiac pipe was well-functioning without regurgitation or obstruction.

11.
Neural Regen Res ; 17(1): 137-143, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34100449

RESUMO

The survival of microglia depends on the colony-stimulating factor-1 receptor (CSF1R) signaling pathway under physiological conditions. Ki20227 is a highly selective CSF1R inhibitor that has been shown to change the morphology of microglia. However, the effects of Ki20227 on the progression of ischemic stroke are unclear. In this study, male C57BL/6 mouse models of focal cerebral ischemic injury were established through the occlusion of the middle cerebral artery and then administered 3 mg/g Ki20227 for 3 successive days. The results revealed that the number of ionized calcium-binding adaptor molecule 1/bromodeoxyuridine double positive cells in the infarct tissue was reduced, the degree of edema was increased, neurological deficits were aggravated, infarct volume was increased, and the number of peri-infarct Nissl bodies was reduced. The number of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells in the peri-infarct tissue was increased. The expression levels of Bax and Cleaved caspase-3 were up-regulated. Bcl-2 expression was downregulated. The expression levels of inflammatory factors and oxidative stress-associated factors were increased. These findings suggested that Ki20227 blocked microglial proliferation and aggravated the pathological progression of ischemia/reperfusion injury in a transient middle cerebral artery occlusion model. This study was approved by the Animal Ethics Committee of Lanzhou University Second Hospital (approval No. D2020-68) on March 6, 2020.

12.
Clin Endocrinol (Oxf) ; 75(4): 470-4, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21521347

RESUMO

BACKGROUND AND OBJECTIVE: Advanced glycosylation end-product receptor (AGER) plays an important role in the development and progression of atherosclerosis. The G82S polymorphism (rs2070600) is located in the ligand-binding V-domain of AGER suggesting a possible influence of this variant on AGER function. The aim of this study is to evaluate the association of the G82S polymorphism with the severity of coronary artery disease (CAD) in patients with or without type 2 diabetes mellitus (T2DM). DESIGN AND METHODS: The AGER gene G82S polymorphism was analysed in 270 nondiabetic and 270 type 2 diabetic Chinese Han patients with angiographically proven CAD (luminal stenosis ≥ 50%). The number of diseased vessels and Gensini score were used to determine the severity of CAD. Genotyping for the G82S polymorphism was performed by PCR-RFLP using restriction enzymes AluI. RESULTS: The frequency of 82S allele was significantly lower in the diabetic CAD patients with multi-vessel disease than in those with single-vessel disease (P = 0·015). When controlled for confounding variables, the 82S allele was associated with decreased risk of multi-vessel disease [P = 0·038, adjusted OR = 0·565 (0·329-0·972)]. The protective effect of the 82S allele against the severity of CAD was not observed in patients with nondiabetic CAD. CONCLUSIONS: AGER 82S allele showed a protective effect on CAD severity in the presence of T2DM in Chinese Han population.


Assuntos
Doença da Artéria Coronariana/genética , Polimorfismo de Nucleotídeo Único/genética , Receptores Imunológicos/genética , Idoso , Povo Asiático/genética , Estudos de Casos e Controles , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Fragmento de Restrição/genética , Receptor para Produtos Finais de Glicação Avançada
13.
Sci Rep ; 11(1): 8684, 2021 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-33888777

RESUMO

Nodal chain (NC) semi-metals have the degeneracy of interlacing rings in their band structure in momentum space. With the projection of degenerate rings towards crystal boundaries, there is a special type of surface dispersion appearing at surface Brillouin zone and termed drumhead surface state (DSS). Previously, experimental investigations on photonic NC and DSS have been done on metallic photonic crystals at microwave frequencies. However, far-field detection of DSS and its coupling to radiative modes in free space have not been studied. In the work, we analyze the photonic DSS in a metallic lattice by angle-resolved far-field reflection measurement and numerical simulation at terahertz (THz) frequencies, and reveal its flatness and boundness in band structure, even in the radiation continuum. Particularly, the DSS band can be tuned being from negatively dispersive via flat to positively dispersive by a single surface parameter, and the DSS at Γ point in surface Brillouin zone is in fact a symmetry-protected bound state in the continuum. Our results might have some potential applications towards THz photonics.

14.
Opt Lett ; 35(11): 1923-5, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20517463

RESUMO

We report the observation of coherent two-photon free-induction decay (FID) in a three-level Lambda system excited by a low-intensity square-modulated laser pulse. Using electromagnetically induced transparency in an Rb85 cold atomic cloud, for what we believe to be the first time, we observe FID signals with coherence time exceeding the relevant atomic excited-state natural lifetime. Because of the on-resonance enhancement, the two-photon FID signal can be observed at the falling edge without using heterodyne means.

15.
Tohoku J Exp Med ; 220(4): 291-7, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20410680

RESUMO

The receptor for advanced glycation end products (RAGE) is a multi-ligand member of the immunoglobulin superfamily and may be involved in the development of diabetic vascular complications. The -374T/A polymorphism in the RAGE gene promoter has been suggested to affect gene transcription. However, the studies on the association between the -374T/A polymorphism and vascular complications in type 2 diabetes mellitus (T2DM) have rendered conflicting results. To shed light on these inconclusive findings, a meta-analysis of all eligible studies concerning this polymorphism was conducted. The PubMed and EMBASE databases were searched for relevant articles up to January 2010. Data on genotypes, allele frequencies and number of cases and controls were extracted. A pooled estimate of the genetic association, the heterogeneity between studies, the sensitivity for HWE (exclusion of studies not in Hardy-Weinberg equilibrium), and the publication bias were investigated. Nine articles with 3,799 cases and 4,899 controls were enrolled in the meta-analysis. The main analysis indicated significant heterogeneity and no association for the allele contrast [random effects odds ratio (RE OR) = 0.92 (0.83 approximately 1.02)]. However, sensitivity analysis for HWE diminished the heterogeneity and showed a marginal association [fixed effects OR = 0.92 (0.86 approximately 0.99)]. The comparison of AA genotype with TA+TT genotypes revealed significant results overall [RE OR = 0.70 (0.57 approximately 0.86)]. Subgroup analyses in Caucasians and macrovascualr disease also produced significant association. In conclusion, the -374A allele of the RAGE gene might be a protective factor for vascular complications in T2DM, especially in Caucasians and macrovascular disease.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Angiopatias Diabéticas/genética , Receptores Imunológicos/genética , Alelos , Vasos Sanguíneos/patologia , Vasos Sanguíneos/fisiopatologia , Bases de Dados Factuais , Diabetes Mellitus Tipo 2/patologia , Diabetes Mellitus Tipo 2/fisiopatologia , Predisposição Genética para Doença , Humanos , Razão de Chances , Polimorfismo Genético , Receptor para Produtos Finais de Glicação Avançada , Fatores de Risco
16.
Artigo em Inglês | MEDLINE | ID: mdl-32722496

RESUMO

In this study, an on-road driving experiment was designed to investigate the visual attention fixation and transition characteristics of drivers when they are under different cognitive workloads. First, visual attention was macroscopically analyzed through the entropy method. Second, the Markov glance one- and two-step transition probability matrices were constructed, which can study the visual transition characteristics under different conditions from a microscopic perspective. Results indicate that the fixation entropy value of male drivers is 23.08% higher than that of female drivers. Under the normal driving state, drivers' fixation on in-vehicle systems is not continuous and usually shifts to the front and left areas quickly after such fixation. When under cognitive workload, drivers' vision transition is concentrated only in the front and right areas. In mild cognitive workload, drivers' sight trajectory is mainly focused on the distant front area. As the workload level increases, the transition trajectory shifts to the junction near the front and far sides. The current study finds that the difference between an on-road test and a driving simulation is that during the on-road driving process, drivers are twice as attentive to the front area than to the driving simulator. The research provides practical guidance for the improvement of traffic safety.


Assuntos
Acidentes de Trânsito/prevenção & controle , Condução de Veículo , Cognição/fisiologia , Fixação Ocular , Carga de Trabalho , Atenção , Feminino , Humanos , Masculino
17.
World Neurosurg ; 141: 421-424, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32561490

RESUMO

BACKGROUND: Dysplastic gangliocytoma is a sporadic cerebellar benign tumor with the characteristics of hamartoma and true tumor, also known as Lhermitte-Duclos disease (LDD). Bone fibrous dysplasia (FD) is a slowly progressive self-limited benign bone tissue disease. Cowden syndrome, an autosomal dominant genetic disorder caused by germline mutations in the PTEN gene, is considered to be closely related to dysplastic gangliocytoma. McCune-Albright syndrome is a disease characterized by café-au-lait skin macules, polyostotic FD, and precocious puberty. The etiologic mechanism of both conditions is not yet clear. We report a rare case of bilateral dysplastic gangliocytoma with concurrent polyostotic FD. CASE DESCRIPTION: We describe a 16-year-old boy with both LDD and FD. He presented for medical examination with headache and poor eyesight. Magnetic resonance imaging revealed proliferation of the skull and abnormal signals in the cerebellum, and supratentorial hydrocephalus. Subtotal resection of the cerebellar tumor was performed, and the diagnosis of LDD and FD was confirmed by histopathology. No other abnormal changes were found in systemic medical examination and no PTEN gene mutation was found in the genetic analysis; therefore, the diagnoses of Cowden syndrome and McCune-Albright syndrome were excluded. CONCLUSIONS: LDD and FD are 2 rare diseases, and the simultaneous occurrence of the 2 conditions has not been reported before, to our knowledge. Our report challenges the etiology of the 2 diseases and the relationship between them, hoping to provide a reference for the study of the 2 diseases.


Assuntos
Neoplasias Cerebelares/cirurgia , Displasia Fibrosa Poliostótica/cirurgia , Ganglioneuroma/cirurgia , Síndrome do Hamartoma Múltiplo/cirurgia , Adolescente , Displasia Fibrosa Poliostótica/diagnóstico , Displasia Fibrosa Poliostótica/patologia , Ganglioneuroma/diagnóstico , Ganglioneuroma/patologia , Hamartoma/patologia , Hamartoma/cirurgia , Síndrome do Hamartoma Múltiplo/patologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino
18.
Opt Express ; 17(9): 7275-84, 2009 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-19399104

RESUMO

Lasing requires an active gain medium and a feedback mechanism. In conventional lasers the feedback is provided externally, e.g. by mirrors. An alternate approach is through Bloch waves in photonic crystals composed of periodic dielectric materials in which propagation of light in certain frequency ranges, known as photonic bandgaps, is forbidden. Compared to periodic crystals, quasicrystals have higher symmetry and are more favorable for the formation of photonic bandgaps. Hence quasicrystals are more efficient in providing the feedback mechanism for lasing. Here we report observation of lasing at visible wavelengths from dye-doped three-dimensional icosahedral quasicrystals fabricated in dichromate gelatin emulsions using a novel seven-beam optical interference holographic method. Multi-directional lasing exhibiting the icosahedral symmetry was observed. The lasing modes and pattern were explained by using the lasing condition expressed in the reciprocal lattice space of the icosahedral quasicrystal.


Assuntos
Cristalização/métodos , Lasers , Iluminação/instrumentação , Dicromato de Potássio/química , Corantes/química , Corantes/efeitos da radiação , Desenho Assistido por Computador , Emulsões/química , Emulsões/efeitos da radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Gelatina/química , Gelatina/efeitos da radiação , Dicromato de Potássio/efeitos da radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Nat Commun ; 10(1): 832, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30783112

RESUMO

Many novel properties of non-Hermitian systems are found at or near the exceptional points-branch points of complex energy surfaces at which eigenvalues and eigenvectors coalesce. In particular, higher-order exceptional points can result in optical structures that are ultrasensitive to external perturbations. Here we show that an arbitrary order exceptional point can be achieved in a simple system consisting of identical resonators placed near a waveguide. Unidirectional coupling between any two chiral dipolar states of the resonators mediated by the waveguide mode leads to the exceptional point, which is protected by the transverse spin-momentum locking of the guided wave and is independent of the positions of the resonators. Various analytic response functions of the resonators at the exceptional points are experimentally manifested in the microwave regime. The enhancement of sensitivity to external perturbations near the exceptional point is also numerically and analytically demonstrated.

20.
Cancer Res ; 65(3): 913-8, 2005 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-15705890

RESUMO

Tumors must manipulate the host vasculature to provide a blood supply adequate for their proliferation. Although tumors may arise as avascular masses, there is increasing evidence that some tumors begin to proliferate by first co-opting preexisting host blood vessels. By fluorescent vascular imaging, we provide evidence that the vasculature in orthotopically implanted melanoma arises from a preexisting red cell-deficient vascular network that remodels to patency to accommodate the requirements of the expanding tumor mass. Topical application of vascular endothelial growth factor to vascular beds generated immediate and robust vascular transitions that were morphologically similar to tumor-induced transitions. N(phi)-nitro-L-arginine, a nitric oxide inhibitor, significantly inhibited the growth of a syngeneic K1735M2 melanoma by reducing blood supply to the tumor by a mechanism independent of endothelial cell proliferation. These findings suggest that tumor-induced remodeling of red cell-deficient vessels to patency contributes to tumor vascularization and growth.


Assuntos
Melanoma Experimental/irrigação sanguínea , Animais , Processos de Crescimento Celular/efeitos dos fármacos , Processos de Crescimento Celular/fisiologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Feminino , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos C3H , Neovascularização Patológica/patologia , Óxido Nítrico/antagonistas & inibidores , Nitroarginina/farmacologia , Pele/irrigação sanguínea , Fator A de Crescimento do Endotélio Vascular/farmacologia
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