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1.
J Plant Physiol ; 266: 153510, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34521019

RESUMO

Source sink balance is one of the major determinants of carbon partitioning in plants. However, its effects on photosynthesis in fruit trees are largely unknown. In this work, the effects of low sink demand on net photosynthetic rate (Pn) and chlorophyll fluorescence after fruit removal (-fruit) in peach (Prunus persica (L.) Batsch cv. 'Zaojiubao') trees were investigated. The stepwise energy flow through photosystem II (PSII) at the reaction center (RC) was analyzed with quantitative analyses of fluorescence transient, also called JIP-test. We found that Pn was significantly lower and closely correlated to the leaf stomatal conductance (Gs) of -fruit trees than that of fruit retained (+fruit) trees. Leaf temperature (Tleaf) of -fruit trees was remarkably higher than that of +fruit trees. Day-time-period assays of chlorophyll (Chl) fluorescence revealed that, in the leaves of -fruit trees, the fluorescence parameters, such as NPQ (non-photochemical quenching coefficient) and ΦD0 (maximum quantum yield of non-photochemical de-excitation), decreased in the morning and recovered to the normal level in the afternoon, whereas other parameters, such as ΦE0 (quantum yield for electron transport at t = 0), Ψ0 (probability that a trapped exciton moves an electron to QA pool), F0 (minimum fluorescence, when all PSII RCs are open) and Wk (relative variable fluorescence at 300 µs of the chlorophyll fluorescence transient), did not. These results suggest that OEC complex and QA pool were irreversibly affected by low sink demand, whereas light harvest antenna and PSII potential efficiency retained a strong ability to recover.

2.
Clin Proteomics ; 18(1): 22, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34418970

RESUMO

BACKGROUND: Preeclampsia and gestational hypertension can cause vascular function impairment in offspring. In our previous work, we described the protein expression profiles of umbilical artery tissues from patients with preeclampsia. METHODS: To gain insights into the mechanisms of vascular dysfunction in adult rats born to preeclamptic dams, we analyzed thoracic aorta tissues by using iTRAQ isobaric tags and 2D nano LC-MS/MS. RESULTS: By using the iTRAQ method, we analyzed 1825 proteins, of which 106 showed significantly different expression in the thoracic aortic. Ingenuity pathway analysis (IPA) showed that the majority of differentially expressed proteins (DEPs) were associated with cardiovascular function. Further analysis indicated that glucose-6-phosphate dehydrogenase (G6PD), which is inhibited by miR-423-5p and activated by TP53, had the strongest effect on cardiovascular function. The expression of G6PD was upregulated in thoracic aorta tissues, as confirmed by Western blotting. The expression of two other vascular function-related proteins, cysteine- and glycine-rich protein 2 (CSRP2) and tubulin alpha-4 A (TUBA4A), was upregulated, as demonstrated by mass spectrometry (MS). CONCLUSIONS: Although the results require further functional validation, these data provide novel findings related to vascular function impairment in the adult offspring of preeclamptic mothers.

3.
BMC Med Imaging ; 20(1): 84, 2020 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-32703209

RESUMO

BACKGROUND: The aim of this was to analyze 4 chest CT imaging features of patients with coronavirus disease 2019 (COVID-19) in Shenzhen, China so as to improve the diagnosis of COVID-19. METHODS: Chest CT of 34 patients with COVID-19 confirmed by the nucleic acid test (NAT) were retrospectively analyzed. Analyses were performed to investigate the pathological basis of four imaging features("feather sign","dandelion sign","pomegranate sign", and "rime sign") and to summarize the follow-up results. RESULTS: There were 22 patients (65.2%) with typical "feather sign"and 18 (52.9%) with "dandelion sign", while few patients had "pomegranate sign" and "rime sign". The "feather sign" and "dandelion sign" were composed of stripe or round ground-glass opacity (GGO), thickened blood vessels, and small-thickened interlobular septa. The "pomegranate sign" was characterized as follows: the increased range of GGO, the significant thickening of the interlobular septum, complicated with a small amount of punctate alveolar hemorrhage. The "rime sign" was characterized by numerous alveolar edemas. Microscopically, the wall thickening, small vascular proliferation, luminal stenosis, and occlusion, accompanied by interstitial infiltration of inflammatory cells, as well as numerous pulmonary interstitial fibrosis and partial hyaline degeneration were observed. Repeated chest CT revealed the mediastinal lymphadenectasis in one patient. Re-examination of the NAT showed another positive anal swab in two patients. CONCLUSION: "Feather sign" and "dandelion sign" were typical chest CT features in patients withCOVID-19; "pomegranate sign" was an atypical feature, and "rime sign" was a severe feature. In clinical work, accurate identification of various chest CT signs can help to improve the diagnostic accuracy of COVID-19 and reduce the misdiagnosis or missed diagnosis rate.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico por imagem , Pulmão/patologia , Pneumonia Viral/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adulto , Idoso , Betacoronavirus/genética , COVID-19 , China , Infecções por Coronavirus/patologia , Feminino , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/patologia , SARS-CoV-2 , Tomografia Computadorizada por Raios X
4.
Acta Pharmacol Sin ; 40(6): 814-822, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30446732

RESUMO

Cancer cells always require more nutrients, energy, and biosynthetic activity to sustain their rapid proliferation than normal cells. Previous studies have shown the impact of THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7), on transcription regulation and cell-cycle arrest in numerous cancers, but its effects on cellular metabolism in cancer cells remain unknown. In this study we elucidated the anticancer mechanism of THZ1 in human non-small-cell lung cancer (NSCLC) cells. We showed that treatment with THZ1 (10-1000 nM) dose-dependently suppressed the proliferation of human NSCLC cell lines H1299, A549, H292, and H23, and markedly inhibited the migration of these NSCLC cells. Furthermore, treatment with THZ1 (50 nM) arrested cell cycle at G2/M phase and induced apoptosis in these NSCLC cell lines. More importantly, we revealed that treatment with THZ1 (50 nM) blocked the glycolysis pathway but had no effect on glutamine metabolism. We further demonstrated that THZ1 treatment altered the expression pattern of glutaminase 1 (GLS1) isoforms through promoting the ubiquitination and degradation of NUDT21. Combined treatment of THZ1 with a glutaminase inhibitor CB-839 (500 nM) exerted a more potent anti-proliferative effect in these NSCLC cell lines than treatment with THZ1 or CB-839 alone. Our results demonstrate that the inhibitory effect of THZ1 on the growth of human NSCLC cells is partially attributed to interfering with cancer metabolism. Thus, we provide a new potential therapeutic strategy for NSCLC treatment by combining THZ1 with the inhibitors of glutamine metabolism.


Assuntos
Antineoplásicos/farmacologia , Fenilenodiaminas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Apoptose/efeitos dos fármacos , Benzenoacetamidas/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quinases Ciclina-Dependentes/antagonistas & inibidores , Sinergismo Farmacológico , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Glutaminase/antagonistas & inibidores , Glicólise/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Tiadiazóis/farmacologia
5.
Oncol Lett ; 16(2): 2085-2090, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30008904

RESUMO

Gastric cancer is a common cancer of the gastrointestinal tract and the second most prevalent cause of cancer-associated mortality globally. Gastric cancer-associated mortality is increased in China compared with that in other countries. Key contributors to the poor prognosis of gastric cancer include late clinical presentation and genetic heterogeneity. Treatment based on the subtype of gastric cancer is important for effective therapy. The overexpression of the erb-b2 receptor tyrosine kinase 2 (ERBB2) gene and protein is associated with gastric cancer in humans. Chemotherapy and targeted therapy may control tumor growth and recurrence, which is an important function of conversion surgery. The present study reported a patient diagnosed with gastric cancer with multiple abdominal cavity and retroperitoneal lymph node metastases. ERBB2 amplification and overexpression were identified in both case reports presented. The patients were treated with four cycles of oxaliplatin, capecitabine and trastuzumab. Computed tomography revealed the lymph node metastases decreased in size following treatment, and surgical resection was performed. The four cycles of oxaliplatin, capecitabine and trastuzumab were continued subsequent to surgical resection at the administered dose. No recurrence was observed for >1 year after surgery. Trastuzumab combined with oxaliplatin and capecitabine as a conversion therapy regime for ERBB2-overexpressing advanced gastric adenocarcinoma increased the likelihood of successful surgical resection, and prolonged progression-free survival.

6.
World J Surg Oncol ; 15(1): 78, 2017 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-28399879

RESUMO

BACKGROUND: Splenosis refers to the heterotopic transplantation of splenic tissue following splenic trauma or splenectomy. Splenosis is typically asymptomatic and is often identified incidentally. CASE PRESENTATION: We report a case of splenosis with colon and stomach invasion presenting as lower gastrointestinal bleeding and mimicking colonic gastrointestinal stromal tumour (GIST). The importance of suspicion for splenosis in patients with a history of splenic injury should be highlighted. Computed tomography (CT)-guided biopsy, nuclear scintigraphy and ferumoxide-enhanced magnetic resonance imaging (MRI) can support an accurate diagnosis. CONCLUSIONS: An accurate diagnosis of splenosis is important to avoid unnecessary operations, especially in patients with previous histories of splenic trauma or splenectomy.


Assuntos
Neoplasias do Colo/diagnóstico , Hemorragia Gastrointestinal/diagnóstico , Neoplasias Gastrointestinais/diagnóstico , Tumores do Estroma Gastrointestinal/diagnóstico , Esplenose/diagnóstico , Adulto , Neoplasias do Colo/cirurgia , Diagnóstico Diferencial , Hemorragia Gastrointestinal/cirurgia , Neoplasias Gastrointestinais/cirurgia , Tumores do Estroma Gastrointestinal/cirurgia , Humanos , Masculino , Esplenose/cirurgia , Tomografia Computadorizada por Raios X
7.
Medicine (Baltimore) ; 95(24): e3916, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27310997

RESUMO

It remains to be seen whether S-1 can be a replacement for infusional fluorouracil (5-FU) for advanced gastric cancer (AGC). The aim of this study was to compare the efficacy and safety of S-1 with 5-FU in AGC.PubMed and Cochrane Library were searched. Randomized controlled trials and meta-analyses comparing S-1 with 5-FU for AGC were eligible. Meta-analysis was performed using RevMan 5.2.Seven trials involving 2443 patients were included. Compared with 5-FU, S-1 showed no significant prolongation of overall survival (OS) (hazard ratio [HR] = 0.91, 95% confidence interval [CI] [0.83-1.01], P = 0.07) and progression-free survival (HR = 0.89, 95% CI [0.70-1.13], P = 0.35), but longer time to treatment failure (HR = 0.74, 95% CI [0.56-0.97], P = 0.03). The objective response rates were comparable (risk ratio [RR] = 1.36, 95% CI [0.95, 1.96], P = 0.10). Regarding treatment-related deaths and hematological toxicities, there was significant heterogeneity between Asian and non-Asian trials, and subgroup analysis was applied. In Asian patients, there was a significant increase in hematological toxicities such as leukopenia (grade 1-4: RR = 1.22, 95% CI [1.08, 1.37], P = 0.001; grade 3-4: RR = 2.21, 95% CI [1.52, 3.21], P < 0.0001), neutropenia (grade 1-4: RR = 1.29, 95% CI [1.11, 1.48], P = 0.0005; grade 3-4: RR = 1.87, 95% CI [1.11, 3.17], P = 0.02), and thrombocytopenia (grade 1-4: RR = 1.71, 95% CI [1.22, 2.41], P = 0.002) in S-1-containing regimens compared with 5-FU-containing regimens, but without significant difference in treatment-related mortality rate (risk difference [RD] = 0.00, 95% CI [-0.01, 0.01], P = 0.68). In non-Asian patients, S-1-containing regimens were, however, associated with significantly fewer treatment-related deaths (RD = -0.02, 95% CI [-0.05, -0.00], P = 0.04), as well as less all grade 1-4 and grade 3-4 hematological toxicities except anemia. There was no significant heterogeneity in nonhematologic toxicities between Asian and non-Asian trials. Lower incidence of grade 1-4 nausea, diarrhea, mucositis, grade 3-4 mucositis, increased creatinine, and decreased calculated creatinine clearance was observed in S-1-containing regimens.S-1 could not improve OS, but increase some hematological toxicities in Asian patients. Therefore, special attention on hematological toxicities should be paid to Asian patients because S-1 is administered on an outpatient basis.


Assuntos
Fluoruracila/uso terapêutico , Estadiamento de Neoplasias , Ácido Oxônico/uso terapêutico , Neoplasias Gástricas/tratamento farmacológico , Tegafur/uso terapêutico , Antimetabólitos Antineoplásicos/uso terapêutico , Combinação de Medicamentos , Humanos , Prognóstico , Neoplasias Gástricas/diagnóstico
8.
Zhongguo Zhong Yao Za Zhi ; 41(3): 410-415, 2016 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-28868855

RESUMO

The techniques and methods of molecular biology have been widely applied in pharmacognosy fields. International development trends of pharmacognosy studies on molecular level were analyzed by bibliometric methods using the SCIE database on Web of Science, the literature distribution, national distribution, agency distribution, periodicals distribution, and hot research topics were described using multivariate statistical analysis and multidimensional scaling analysis method,etc. The number of international pharmacognosy literature on molecular level is increasing year by year. USA, China and Japan have close cooperation, and focus on molecular identification and genetic diversity. Chinese scientists issued high-impact factor journals papers and high citations amount in the international forefront. The international pharmacognosy research on molecular level has developed rapidly. Chinese research has a significant influence.The molecular mechanism of the formation of Dao-di Herbs may become the next hotspot.


Assuntos
Biologia Molecular/estatística & dados numéricos , Farmacognosia/estatística & dados numéricos , Publicações/estatística & dados numéricos , Bibliometria , China , Fator de Impacto de Revistas , Biologia Molecular/tendências , Farmacognosia/tendências , Plantas Medicinais/química , Plantas Medicinais/genética , Plantas Medicinais/metabolismo
9.
Sci Rep ; 5: 8872, 2015 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-25747708

RESUMO

In the present study, we presented the population genetic data and their forensic parameters of 21 non-CODIS autosomal STR loci in Chinese Guanzhong Han population. A total of 166 alleles were observed with corresponding allelic frequencies ranging from 0.0018 to 0.5564. No STR locus was observed to deviate from the Hardy-Weinberg equilibrium and linkage disequilibriums after applying Bonferroni correction. The cumulative power of discrimination and probability of exclusion of all the 21 STR loci were 0.99999999999999999993814 and 0.999998184, respectively. The results of genetic distances, phylogenetic trees and principal component analysis revealed that the Guanzhong Han population had a closer relationship with Ningxia Han, Tujia and Bai groups than other populations tested. In summary, these 21 STR loci showed a high level of genetic polymorphisms for the Guanzhong Han population and could be used for forensic applications and the studies of population genetics.


Assuntos
Mapeamento Cromossômico/métodos , Frequência do Gene/genética , Variação Genética/genética , Genética Populacional , Repetições de Microssatélites/genética , Locos de Características Quantitativas/genética , China/epidemiologia , China/etnologia , Bases de Dados Genéticas , Humanos , Filogenia
10.
Opt Lett ; 40(5): 744-7, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25723422

RESUMO

A long-range surface plasmon resonance (LRSPR) sensor based on dielectric/silver-coated hollow fiber (HF) is proposed. It can detect the refractive index (RI) of sensed liquid filled in the hollow core of the sensor. A HF LRSPR sensor with 90-nm-thick silver layer and 260-nm-thick OC300 layer is fabricated. Experiments are taken to evaluate the performance of the sensor by measuring the transmission spectra. Theoretical analysis based on a ray model is also taken, and the results agree well with the experimental results. The proposed sensor has similar sensitivity but much smaller SPR dip width than the silver-coated HF SPR sensor. Thus figure of merit of the sensor is enhanced approximately five times. The stability of the sensor is also improved because the dielectric layer acts as a protection layer for the damageable silver layer.


Assuntos
Fibras Ópticas , Prata , Ressonância de Plasmônio de Superfície/instrumentação , Impedância Elétrica
11.
Opt Express ; 22(3): 2174-84, 2014 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-24663509

RESUMO

We present the potential of ultrathin bilayer metallic nanofilms for use as broadband antireflection coatings in the terahertz frequency range. The metallic layers are modeled using a wave-impedance matching approach. The experimental and theoretical results are in good agreement. Further, a novel method using our broadband antireflection coatings is proposed to eliminate unwanted reflections that interfere with the important reflection from the sample in terahertz reflection measurement. The proposed method significantly improves the calculation of the optical properties of liquid and biological samples.


Assuntos
Lentes , Membranas Artificiais , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Dispositivos Ópticos , Radiação Terahertz , Absorção Fisico-Química , Espalhamento de Radiação
12.
Yi Chuan ; 35(5): 607-15, 2013 May.
Artigo em Chinês | MEDLINE | ID: mdl-23732667

RESUMO

Sterol regulatory element binding protein 1 (SREBP-1) is one of the important nuclear transcription factors. SREBP-1 can maintain lipids dynamic equilibrium by regulating the expression of enzymes required for synthesis of endogenous cholesterol, fatty acids, triglycerides and phospholipids. Anomalies of SREBP-1 and its target genes can cause a series of metabolic diseases such as insulin resistance, type Ⅱ diabetes, heart dysfunction, vascular complications and hepatic steatosis. In these years, the development of high-throughput technologies has greatly expanded our knowledge about SREBP-1 target genes and the pattern of transcriptional regulation. Here we reviewed recent research progress of SREBP-1, with a focus on the protein structure, activation process, DNA binding sites and target genes. Most importantly, we showed the transcriptional regulatory networks based on omics datasets, which will contribute to a better understanding of the role of SREBP-1 in lipid metabolism and provide new clues for the treatment of lipid metabolism disorders.


Assuntos
Regulação da Expressão Gênica , Redes Reguladoras de Genes , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Animais , Humanos , Metabolismo dos Lipídeos , Proteína de Ligação a Elemento Regulador de Esterol 1/química , Proteína de Ligação a Elemento Regulador de Esterol 1/genética
13.
Opt Express ; 21(26): 32349-57, 2013 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-24514827

RESUMO

A new kind of surface plasmon resonance (SPR) sensor based on silver-coated hollow fiber (HF) structure for the detection of liquids with high refractive index (RI) is presented. Liquid sensed medium with high RI is filled in the hollow core of the HF and its RI can be detected by measuring the transmission spectra of the HF SPR sensor. The designed sensors with different silver thicknesses are fabricated and the transmission spectra for filled liquids with different RI are measured to investigate the performances of the sensors. Theoretical analysis is also carried out to evaluate the performance. The simulation results agree well with the experimental results. Factors that might affect sensitivity and detection accuracy of the sensor are discussed. The highest sensitivity achieved is 6,607 nm/RIU, which is comparable to the sensitivities of the other reported fiber SPR sensors.


Assuntos
Técnicas Biossensoriais/instrumentação , Tecnologia de Fibra Óptica/instrumentação , Refratometria/instrumentação , Soluções/análise , Soluções/química , Ressonância de Plasmônio de Superfície/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Porosidade
14.
Appl Opt ; 51(30): 7276-85, 2012 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-23089782

RESUMO

Dielectric-coated metallic hollow waveguides (DMHW) are drawing considerable attention for their application in terahertz (THz) waveguiding. This paper theoretically analyzes the multilayer structure to reduce the transmission and bending loss of DMHW. The efficiency of THz multilayer DMHW depends on a proper selection of dielectric materials and geometrical parameters. The low-loss properties are demonstrated by studying the multilayer gold waveguides with a stack of polypropylene (PP) and Si-doped polypropylene (PP(Si)). Comparisons are made with single-layer Au/PP and Au-only waveguides. The effect of dielectric absorption is discussed in detail. It is found that low index dielectric causes more additional loss than that of high index dielectric layers. Several design considerations for the THz multilayer DMHW are pointed out by studying the effects of multilayer structure parameters with a stack of polyethylene (PE) and TiO(2)-doped polyethylene (PE(TiO2)). We conclude that the inner radius of the waveguide and the refractive indices of the dielectrics tend to be larger in order to reduce the influence of material absorption. An optimal value exists for the total number of layers when the dielectrics are absorptive. The absorption tolerances are pointed out to guarantee a smaller loss for multilayer DMHW than that of metal-only waveguide. Finally, a fabrication method for THz multilayer DMHW Ag/PE/PE(TiO2) is proposed based on co-rolling technique.

15.
Yi Chuan ; 34(2): 198-207, 2012 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-22382061

RESUMO

Diabetic neuropathy (DN) is defined as the presence of symptoms and/or signs of peripheral nerve dysfunction in people with diabetes. The aim of this study is to screen differentially expressed genes in peripheral ganglia in early stage type Ⅱ experimental diabetic rats. We compared gene expression profiles of peripheral ganglia in type Ⅱ diabetic and nondiabetic rats based on Illumina® Sentrix® BeadChip arrays. The results showed that 158 out of a total of 12 604 known genes were significantly differentially expressed, including 87 up-regulated and 71 down-regulated genes, in diabetic rats compared with those in the nondiabetic rats. It is noted that some up-regulated genes are involved in the biological processes of neuronal cytoskeleton and motor proteins. In contrast, the down-regulated genes are associated with the response to virus\biotic stimulus\ other organism in diabetic rats. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the most significant pathway enriched in the changed gene set is metabolism (P < 0.001). These results indicated that metabolic changes in peripheral ganglia of diabetic rats could be induced by hyperglycemia. Hyperglycemia could change the expression of genes involved in neuronal cytoskeleton and motor proteins through immune inflammatory response, and then impair the structure and function of the peripheral ganglia.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Neuropatias Diabéticas/metabolismo , Gânglios/metabolismo , Perfilação da Expressão Gênica , Animais , Masculino , Ratos , Ratos Sprague-Dawley
16.
Opt Lett ; 36(17): 3461-3, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21886244

RESUMO

We report the optimal design for hollow fiber inner-coated with metallic and multidielectric layers by using ray-optics theory. Transmission characteristics of the multilayer hollow fiber are more dependent on the film surface roughness in the IR region. Comparisons of fibers with smooth and rough films are made and discussed in detail. The optimal design for film thickness, inner radius, and the number of layers and refractive indices is presented. The calculation results are important for structure design, material selection, and fabrication when considering imperfections in film-coating techniques. Multilayer fibers are fabricated based on the calculation and experimental results agree with the theoretical ones.

17.
Opt Express ; 19(25): 24967-79, 2011 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-22273890

RESUMO

Transmission characteristics at terahertz (THz) frequencies are numerically analyzed for elliptical dielectric-coated metallic hollow fiber (DMHF). Attenuation constants, group velocity, modal birefringence, and modal power fraction in the air core are presented. Optimization of the fiber geometry is investigated to reduce the attenuation and to increase the birefringence simultaneously. Modal birefringence of 3.3 × 10 -2 and attenuation of 2.4 dB/m are expected. It is found that a desirable ellipticity of the air core is around 3. And both the modal birefringence and the attenuation constant are inversely proportional to the cube of the core size. Multiple dielectric layers significantly reduce the attenuation and meanwhile have little influence on the modal birefringence.


Assuntos
Desenho Assistido por Computador , Tecnologia de Fibra Óptica/instrumentação , Modelos Teóricos , Refratometria/instrumentação , Birrefringência , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Porosidade , Espalhamento de Radiação , Radiação Terahertz
18.
Opt Lett ; 34(14): 2231-3, 2009 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-19823558

RESUMO

We report calculation results for the transmission characteristics of terahertz hollow fibers with inner coatings of absorptive dielectric and metal layers. The absorption property of the dielectric film has an obvious influence on the transmission property of terahertz hollow fiber, because the optimum thickness of the dielectric layer is several tens of micrometers. Calculations were conducted on the loss properties of the hollow fiber with and without the absorptive dielectric layer. Important results were obtained, such as the optimum refractive index for the absorptive dielectric layer and the absorption tolerances for hollow fibers with various inner diameters.

19.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 40(2): 236-9, 2009 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-19462897

RESUMO

OBJECTIVE: To detect the expression of RhoC and Ki67 in squamous carcinoma of cervix and to reveal the correlation of RhoC and Ki67 with clinic pathological parameters of cervix carcinoma. METHODS: The expressions of RhoC and Ki67 were evaluated in 26 cases of cervical intraepithelial neoplasia (CIN) and 57 cases of squamous carcinoma of cervix(SCC) by immunohistochemistry, while 14 cases of normal cervical epithelium(NCE) were taken as control. RESULTS: Immunohistochemical staining demonstrated RhoC expression in 82.46% (47/57) of SCC, 15.38% (2/13) of CIN II/III, and negative expression in NCE and CIN I. The positive rate of RhoC expression in SCC was significantly higher than that in NCE and CIN (P < 0.05). The expression of RhoC in SCC was significantly correlated with pelvic lymph node metastasis and depth of stroma infiltration, but not correlated with age, FIGO staging,histologic grade and vascular space involvement. The positive rates of Ki67 expression in NCE, CIN I, CIN II/III and SCC were 28.57%, 38.46%, 100% and 96.49% respectively. The positive rates of Ki67 expression in SCC and CIN II/III were significantly higher than those in NCE and CIN I (P < 0.05). The expression of Ki67 in SCC was not correlated with the major clinic pathological parameters. There was no obvious relationship between the expression of RhoC gene and Ki67 antigen in SCC (P > 0. 05). CONCLUSIONS: The overexpression of RhoC may play an important role in the invasion and metastasis of SCC. RhoC may be a potential marker to identify SCC patients with high risk of invasion and metastasis.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/metabolismo , Antígeno Ki-67/metabolismo , Neoplasias do Colo do Útero/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Adulto , Idoso , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/patologia , Neoplasia Intraepitelial Cervical/metabolismo , Feminino , Humanos , Antígeno Ki-67/genética , Pessoa de Meia-Idade , Invasividade Neoplásica , Metástase Neoplásica , Neoplasias do Colo do Útero/patologia , Adulto Jovem , Proteínas rho de Ligação ao GTP/genética , Proteína de Ligação a GTP rhoC
20.
Appl Opt ; 47(34): 6340-4, 2008 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-19037360

RESUMO

A method is proposed to evaluate the material dispersion of dielectric film in dielectric-coated silver hollow fiber. Cauchy's formulas that characterize the dispersion property were obtained for several commonly used dielectric materials by using the measured data of loss spectra of the hollow fibers. The wavelengths of the loss peaks and valleys in the loss spectra can be predicted more accurately when taking into consideration of the material dispersion. The derived Cauchy's formulas play an important role in the design of infrared hollow fiber for multiwavelength delivery.

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