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Endostatin gene therapy stimulates upregulation of ICAM-1 and VCAM-1 in a metastatic renal cell carcinoma model

Chaves, K. C. B.; Peron, J. P. S.; Chammas, R.; Turaca, L. T.; Pesquero, J. B.; Braga, M. S.; Foguer, K.; Schor, N.; Bellini, M. H.
Fonte: NATURE PUBLISHING GROUP; LONDON Publicador: NATURE PUBLISHING GROUP; LONDON
Tipo: Artigo de Revista Científica
Português
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One of the greatest challenges in urological oncology is renal cell carcinoma (RCC), which is the third leading cause of death in genitourinary cancers. RCCs are highly vascularized and respond positively to antiangiogenic therapy. Endostatin (ES) is a fragment of collagen XVIII that possesses antiangiogenic activity. In this study, we examined the potential of ES-based antiangiogenic therapy to activate tumor-associated endothelial cells in metastatic RCC (mRCC). Balb/c-bearing Renca cells were treated with NIH/3T3-LendSN or, as a control, with NIH/3T3-LXSN cells. The T-cell subsets and lymphocyte populations of tumors, mediastinal lymph nodes and the spleen were assessed by flow cytometry. The expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was assessed by real-time PCR, flow cytometry and immunohistochemistry analysis. ES gene therapy led to an increase in the percentage of infiltrating CD4-interferon (IFN)-gamma cells (P<0.05), CD8-IFN-gamma cells (P<0.01) and CD49b-tumor necrosis factor-alpha cells (P<0.01). In addition, ES therapy caused an increase at the mRNA level of ICAM-1 (1.4-fold; P<0.01) and VCAM-1 (1.5-fold) (control vs treated group; P<0.001). Through flow cytometry...

The 2:1 cycloadducts from [3+2] 1,3-dipolar cycloaddition of nitrile oxide and vinylacetic acid. Synthesis and liquid crystal behaviour

Tavares, Aline; Vilela, Guilherme D.; Toldo, Josene; Goncalves, Paulo F. B.; Eccher, Juliana; Bechtold, Ivan H.; Sampaio, Anderson R.; Viscovini, Ronaldo C.; Schneider, Paulo H.; Merlo, Aloir A.
Fonte: TAYLOR & FRANCIS LTD; ABINGDON Publicador: TAYLOR & FRANCIS LTD; ABINGDON
Tipo: Artigo de Revista Científica
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Four liquid crystals (LC) 3,7a-bis(4-alkyloxyphenyl)-7,7a-dihydro-6H-isoxazolo[2,3-d][1,2,4]oxadiazol-6-yl)acetic acid (7a-d) were synthesised and the mesomorphic behaviour reported. The LCs were characterised as 2: 1 bisadducts, which were obtained from a double [3+2] 1,3-dipolar cycloaddition. In the first step, the cycloaddition of 4-alkyloxyphenylnitrile oxide (4a-d) and vinylacetic acid (5) gave the initial unobserved 1:1 cycloadducts 2-[3-(4-alkyloxyphenyl)-4,5-dihydroisoxazol-5-yl]acetic acid (6a-d). In the second step, the addition of a second equivalent of 4 to 6 yielded the 2: 1 bisadducts 7a-d without any traces of 6. All compounds 7a-d were unstable during the transition from the mesophase to the isotropic state upon first heating as evidenced by the large peaks in the differential scanning calorimetry traces. Due to the chemical instability of the compounds upon heating, the transition temperature related to the smectic C to smectic A transitions was acquired by means of an image processing method. X-Ray diffraction experiments were also used to analyse the liquid-crystalline phases. A theoretical calculation was performed using density functional theory (DFT) methods at the PBE1PBE/6-311+G(2d,p) level (with solvent effect) in order to get information about the energetic profile of the 2: 1 cycloaddition. DFT studies revealed that the cycloaddition process is controlled by the HOMO(dipolarophile) - LUMO(1...

Structural elucidation of the red dye obtained from reaction of 1,8-naphthalenediol with 1,1-diphenylprop-2-yn-1-ol : a correction

Campos, Ana M. F. Oliveira; Carvalho, Luís H. Melo de; Silva, Artur M. S.; Martins, Cristina I.; Coelho, Paulo J.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2003 Português
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The structure of the intensely coloured red product obtained through the reaction of 1,8-naphthalenediol with 1,1-diphenylprop-2-yn-1-ol was reinvestigated. Instead of the expected permanent open form of the naphthopyran, the dye presents the alpha,beta-unsaturated chain at a different position of the naphthalene nucleus. The structure of this compound was elucidated on the basis of detailed spectral analysis, including 2D NMR experiments.; Fundação para a Ciência e Tecnologia - PRAXIS XXI/P/QUI/10021/1998.

Nitric oxide, cholesterol oxides and endothelium-dependent vasodilation in plasma of patients with essential hypertension

Moriel,P.; Sevanian,A.; Ajzen,S.; Zanella,M.T.; Plavnik,F.L.; Rubbo,H.; Abdalla,D.S.P.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2002 Português
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The objective of the present study was to identify disturbances of nitric oxide radical (·NO) metabolism and the formation of cholesterol oxidation products in human essential hypertension. The concentrations of·NO derivatives (nitrite, nitrate, S-nitrosothiols and nitrotyrosine), water and lipid-soluble antioxidants and cholesterol oxides were measured in plasma of 11 patients with mild essential hypertension (H: 57.8 ± 9.7 years; blood pressure, 148.3 ± 24.8/90.8 ± 10.2 mmHg) and in 11 healthy subjects (N: 48.4 ± 7.0 years; blood pressure, 119.4 ± 9.4/75.0 ± 8.0 mmHg).Nitrite, nitrate and S-nitrosothiols were measured by chemiluminescence and nitrotyrosine was determined by ELISA. Antioxidants were determined by reverse-phase HPLC and cholesterol oxides by gas chromatography. Hypertensive patients had reduced endothelium-dependent vasodilation in response to reactive hyperemia (H: 9.3 and N: 15.1% increase of diameter 90 s after hyperemia), and lower levels of ascorbate (H: 29.2 ± 26.0, N: 54.2 ± 24.9 µM), urate (H: 108.5 ± 18.9, N: 156.4 ± 26.3 µM), ß-carotene (H: 1.1 ± 0.8, N: 2.5 ± 1.2 nmol/mg cholesterol), and lycopene (H: 0.4 ± 0.2, N: 0.7 ± 0.2 nmol/mg cholesterol), in plasma, compared to normotensive subjects. The content of 7-ketocholesterol...

High mobility group box 1 as a mediator of endotoxin administration after hemorrhagic shock-primed lung injury

Guo,F.; Shi,Y.; Xu,H.; Ding,J.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2009 Português
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High mobility group box 1 (HMGB1) was discovered as a novel late-acting cytokine that contributes to acute lung injury (ALI). However, the contribution of HMGB1 to two-hit-induced ALI has not been investigated. To examine the participation of HMGB1 in the pathogenesis of ALI caused by the two-hit hypothesis, endotoxin was injected intratracheally in a hemorrhagic shock-primed ALI mouse model. Concentrations of HMGB1 in the lung of the shock group were markedly increased at 16 h (1.63 ± 0.05, compared to the control group: 1.02 ± 0.03; P < 0.05), with the highest concentration being observed at 24 h. In the sham/lipopolysaccharide group, lung HMGB1 concentrations were found to be markedly increased at 24 h (1.98 ± 0.08, compared to the control group: 1.07 ± 0.03; P < 0.05). Administration of lipopolysaccharide to the hemorrhagic shock group resulted in a notable HMGB1 increase by 4 h, with a further increase by 16 h. Intratracheal lipopolysaccharide injection after hemorrhagic shock resulted in the highest lung leak at 16 h (2.68 ± 0.08, compared to the control group: 1.05 ± 0.04; P < 0.05). Compared to the hemorrhagic shock/lipopolysaccharide mice, blockade of HMGB1 at the same time as lipopolysaccharide injection prevented significantly pulmonary tumor necrosis factor-alpha...

Herpesvírus bovinos (BoHV-1.1 e BoHV-1.2b) em forma infecciosa em encéfalos de bovinos submetidos ao diagnóstico de raiva no estado do Rio Grande do Sul

Batista,H.B.C.R.; Schmidt,E.; Spilki,F.R.; Franco,A.C.; Roehe,P.M.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 Português
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Verificou-se a incidência de herpesvírus bovinos (BoHVs) em encéfalos de bovinos submetidos ao diagnóstico de raiva no estado do Rio Grande do Sul. Para tanto, amostras coletadas durante dois anos (n=70) foram submetidas ao isolamento viral em cultivos celulares. Os BoHVs foram isolados em dois (2,9%) encéfalos. Após serem submetidas à caracterização antigênica e molecular, as amostras foram subtipadas como BoHV-1.1 e BoHV-1.2b. A BoHV-1.1 foi isolada de um encéfalo que foi também positivo para raiva. O vírus da raiva foi identificado em 11 amostras (15,7%). Estes achados revelam que a incidência de BoHVs em forma infecciosa em bovinos com encefalite foi baixa, embora represente 16,7% (2/12) dos encéfalos nos quais um agente viral foi identificado. Tal fato confirma a já reportada associação entre BoHV-1 e encefalites. Esse é o primeiro relato da ocorrência de BoHV-1.2b, um subtipo considerado menos patogênico, em um caso de doença neurológica em bovinos.

Attenuation of endotoxin-induced multiple organ dysfunction by 1-amino-2-hydroxy-guanidine, a potent inhibitor of inducible nitric oxide synthase.

Ruetten, H.; Southan, G. J.; Abate, A.; Thiemermann, C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1996 Português
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1. We have investigated the effects of (i) several guanidines on the activity of the inducible isoform of nitric oxide (NO) synthase (iNOS) in murine cultured macrophages and rat aortic vascular smooth muscle cells (RASM); and (ii) 1-amino-2-hydroxy-guanidine, the most potent inhibitor of iNOS activity discovered, on haemodynamics, multiple organ (liver, renal, and pancreas) dysfunction and iNOS activity in rats with endotoxic shock. 2. The synthesized guanidine analogues caused concentration-dependent inhibitions of the increase in nitrite formation caused by lipopolysaccaride (LPS, 1 microgram ml-1) in J774.2 macrophages and RASM cells with the following rank order of potency: 1-amino-2-hydroxy-guanidine > 1-amino-2-methyl-guanidine > 1-amino-1-methyl-guanidine > 1-amino-1,2-dimethyl-guanidine. Interestingly, 1-amino-2-hydroxy-guanidine (IC50: J774.2, 68 microM; RASM, 114 microM) was more potent in inhibiting nitrite formation caused by LPS than NG-methyl-L-arginine, but less potent than aminoethyl-isothiourea. 3. In the anaesthetized rat, LPS caused a fall in mean arterial blood pressure (MAP) from 115 +/- 4 mmHg (time 0) to 98 +/- 5 mmHg at 2 h (P < 0.05, n = 10) and 69 +/- 5 mmHg at 6 h (P < 0.05, n = 10). The pressor effect of noradrenaline (NA...

Efeito de produto a base de azadiractinano controle de Sitophilus zeamais Mots.1855 (Coleoptera: Curculionidae)

BARILLI, D. R.; WENGRAT, A. P. G. S.; UEMURA-LIMA, D. H.; GAZOLA, D.; WEBER, P.; PIETROWSKI, V.; RINGENBERG, R.; GARCIA, M. da S.
Fonte: Cadernos de Agroecologia, v. 9, n. 1, 2014. Publicador: Cadernos de Agroecologia, v. 9, n. 1, 2014.
Tipo: Artigo em periódico indexado (ALICE)
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O milho, ao ser armazenado, fica vulnerável a diferentes intempéries, dentre elas, o ataque de pragas como o Sitophilus zeamais, que causa grande perda de peso e qualidade dos grãos. O presente estudo teve como objetivo, avaliar o potencial de utilização do produto a base de azadiractina (Azamax®) no controle de S. zeamais. O produto foi aplicado em cinco diferentes doses (0,1; 0,2; 0,3; 0,4; 0,5%) mais a testemunha (água destilada), utilizando cinza como veículo. Os tratamentos foram aplicados em cinza, 1:1 (p:v) e deixado secar, sendo posteriormente aplicação em 100g de grãos. Adicionaram-se a esses grãos 10 adultos de S. zeamais. A avaliação de mortalidade foi realizada aos 10 dias após aplicação. Foi observado eficiência de controle de 60% na dose de 0,5%.; 2014; Edição dos resumos do I Congresso Paranaense de Agroecologia ?Pinhais/PR?29 e 30/05/2014.

The pharmacokinetics pharmacodynamics safety and tolerability of NN2211 a new long-acting GLP-1 derivative in healthy men

Agerso, H.; Jensen, L.; Elbrond, B.; Rolan, P.; Zdravkovic, M.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
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AIMS/HYPOTHESIS: Glucagon-like peptide-1 (GLP-1), a polypeptide hormone secreted by the l-cells in the gastrointestinal tract, has shown promising effects as a new treatment modality for patients with Type II (non-insulin-dependent) diabetes mellitus. However, the pharmacokinetic profile of native GLP-1 with a rapid elimination has limited its therapeutic potential. NN2211 is a fatty acid derivative of GLP-1, which pre-clinically has shown a protracted pharmacokinetic profile, while maintaining its biological activity. This study aimed to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of NN2211 in healthy male subjects following seven days treatment. METHODS: In a double-blind, randomized, dose escalation, placebo controlled study, healthy male subjects were enrolled at five consecutive dose levels of NN2211 (1.25, 5.0, 7.5, 10.0, 12.5 μg/kg). Six subjects were allocated at random at each dose level to active or placebo treatment with a ratio of 2:1. Dosing with NN2211 was performed on day 1, and days 5–11. The 84-h pharmacokinetics and 24-h glucose and insulin profiles were assessed on day 1 and day 11. Results: Following s. c. administration the half-life of NN2211 was found to be 12.6 ± 1.1 h, with a subsequent accumulation index after a daily dose for seven days of 1.4–1.5. There were dose-proportional increases in exposure (AUC and Cmax) with increasing doses. Overall...

The presence and severity of chronic kidney disease predicts all-cause mortality in type 1 diabetes

Groop, P.H.; Thomas, M.; Moran, J.; Waden, J.; Thorn, L.; Makinen, V.P.; Rosengard-Barlund, M.; Saraheimo, M.; Hietala, K.; Heikkia, O.; Forsblom, C.
Fonte: American Diabetes Association Publicador: American Diabetes Association
Tipo: Artigo de Revista Científica
Publicado em //2009 Português
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OBJECTIVES This study aimed to identify clinical features associated with premature mortality in a large contemporary cohort of adults with type 1 diabetes. RESEARCH DESIGN AND METHODS The Finnish Diabetic Nephropathy (FinnDiane) study is a national multicenter prospective follow-up study of 4,201 adults with type 1 diabetes from 21 university and central hospitals, 33 district hospitals, and 26 primary health care centers across Finland. RESULTS During a median 7 years of follow-up, there were 291 deaths (7%), 3.6-fold (95% CI 3.2–4.0) more than that observed in the age- and sex-matched general population. Excess mortality was only observed in individuals with chronic kidney disease. Individuals with normoalbuminuria showed no excess mortality beyond the general population (standardized mortality ratio [SMR] 0.8, 95% CI 0.5–1.1), independent of the duration of diabetes. The presence of microalbuminuria, macroalbuminuria, and end-stage kidney disease was associated with 2.8, 9.2, and 18.3 times higher SMR, respectively. The increase in mortality across each stage of albuminuria was equivalent to the risk conferred by preexisting macrovascular disease. In addition, the glomerular filtration rate was independently associated with mortality...

Electron and positron scattering from 1,1-C₂H₂F₂

Makochekanwa, C.; Kato, H.; Hoshino, M.; Bettega, M. H. F.; Lima, M. A. P.; Sueoka, O.; Tanaka, H.
Fonte: American Institute of Physics (AIP) Publicador: American Institute of Physics (AIP)
Tipo: Artigo de Revista Científica
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1,1-difluoroethylene (1,1-C₂H₂F₂) molecules have been studied for the first time experimentally and theoretically by electron and positron impact. 0.4-1000 eV electron and 0.2-1000 eV positron impact total cross sections (TCSs) were measured using a retarding potential time-of-flight apparatus. In order to probe the resonances observed in the electron TCSs, a crossed-beam method was used to investigate vibrational excitation cross sections over the energy range of 1.3-49 eV and scattering angles 90 degrees and 120 degrees for the two loss energies 0.115 and 0.381 eV corresponding to the dominant C-H (ν₂ and ν₉) stretching and the combined C-F (ν₃) stretching and CH₂ (ν₁₁) rocking vibrations, respectively. Electron impact elastic integral cross sections are also reported for calculations carried out using the Schwinger multichannel method with pseudopotentials for the energy range from 0.5 to 50 eV in the static-exchange approximation and from 0.5 to 20 eV in the static-exchange plus polarization approximation. Resonance peaks observed centered at about 2.3, 6.5, and 16 eV in the TCSs have been shown to be mainly due to the vibrational and elastic channels, and assigned to the B₂, B₁, and A₁ symmetries, respectively. The pi* resonance peak at 1.8 eV in C₂H₄ is observed shifted to 2.3 eV in 1...

Lasiodiplodan, an exocellular (1 -> 6)-beta-d-glucan from Lasiodiplodia theobromae MMPI: production on glucose, fermentation kinetics, rheology and anti-proliferative activity

Alves da Cunha, Mario A.; Turmina, Janaina A.; Ivanov, Raphael C.; Barroso, Roney R.; Marques, Patricia T.; Fonseca, Eveline A. I.; Fortes, Zuleica B.; Dekker, Robert F. H.; Khaper, Neelam; Barbosa, Aneli M.
Fonte: SPRINGER HEIDELBERG; HEIDELBERG Publicador: SPRINGER HEIDELBERG; HEIDELBERG
Tipo: Artigo de Revista Científica
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Lasiodiplodan, an exopolysaccharide of the (1 -> 6)-beta-d-glucan type, is produced by Lasiodiplodia theobromae MMPI when grown under submerged culture on glucose. The objective of this study was to evaluate lasiodiplodan production by examining the effects of carbon (glucose, fructose, maltose, sucrose) and nitrogen sources (KNO3, (NH4)(2)SO4, urea, yeast extract, peptone), its production in shake flasks compared to a stirred-tank bioreactor, and to study the rheology of lasiodiplodan, and lasiodiplodan's anti-proliferative effect on breast cancer MCF-7 cells. Although glucose (2.05 +/- A 0.05 g L-1), maltose (2.08 +/- A 0.04 g L-1) and yeast extract (2.46 +/- A 0.06 g L-1) produced the highest amounts of lasiodiplodan, urea as N source resulted in more lasiodiplodan per unit biomass than yeast extract (0.74 +/- A 0.006 vs. 0.22 +/- A 0.008 g g(-1)). A comparison of the fermentative parameters of L. theobromae MMPI in shake flasks and a stirred-tank bioreactor at 120 h on glucose as carbon source showed maximum lasiodiplodan production in agitated flasks (7.01 +/- A 0.07 g L-1) with a specific yield of 0.25 +/- A 0.57 g g(-1) and a volumetric productivity of 0.06 +/- A 0.001 g L-1 h(-1). A factorial 2(2) statistical design developed to evaluate the effect of glucose concentration (20-60 g L-1) and impeller speed (100-200 rpm) on lasiodiplodan production in the bioreactor showed the highest production (6.32 g L-1) at 72 h. Lasiodiplodan presented pseudoplastic behaviour...

Florida aeronautical chart

Florida -- Dept. of Transportation. -- Aviation Bureau; Jeppesen and Conpany, Denver; H.M. Gousha Company
Fonte: published by H.M. Gousha Co. for the Department ( San Jose ) Publicador: published by H.M. Gousha Co. for the Department ( San Jose )
Tipo: cartographic Formato: col. map : ; 72 x 80 cm. fold. to 19 x 21 cm.
Publicado em //1976 Português
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Lambert conformal conic projection. Standard parallels 33 ̊and 45.̊; Title from verso, outside when folded.; "Copyright 1969, Jeppesen and Company, Denver, Colorado.; On verso: Illus.; Directory of public air ports; Florida air mileage charts.; Insets: Tampa - St. Petersburg - Clearwater; Miami, scale 1 inch 4 SM.; (Funding) Funded in part by the University of Florida, the Florida Heritage Project of the State University Libraries of Florida, the Institute for Museum and Library Services, and the U.S. Department of Education's TICFIA granting program.

Conformational dynamics of substituted N-acetyl-N-phenylbenzylamines. H-1-DNMR and AM1-MO study

Jullian, Carolina; Araya Maturana, Ramiro Juan; Pessoa, H.; Valderrama, J.; Saitz B., C.; Weiss López, Boris Enrique
Fonte: SOCIEDAD CHILENA DE QUIMICA Publicador: SOCIEDAD CHILENA DE QUIMICA
Tipo: Artículo de revista
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Activation parameters for the rotation around the methylene-nitrogen single bond found in a series of four 2,2'-disubstituted N-acetyl-N-phenylbenzylamines, dissolved in DMSO-d(6), were measured employing the temperature dependence of the H-1-NMR spectrum lineshape between 340 and 400 K. The results are (I) 2 - [N-acetyl -N- (2-acetamidophenyl) aminomethyl] phenyl acetate DeltaG(not equal) =79.9 +/-2.0 kJ/mol (370K), DeltaH(not equal) =96.2 +/-6.0 kJ/mol and DeltaS(not equal) =+45 +/- 20 J/Kmol; (II) 2 [N - acetyl - N - (2-acetyioxybenzyl)amino]benzylacetate DeltaG(not equal) =82.0 +/-2.0 kJ/mol (370K), DeltaH(not equal) =79.1 +/-6.0 kcal/mol and DeltaS(not equal) =8 +/- 20 J/Kmol; (III) 2 - [N - Acetyl - N - (2-nitrobenzyl)amino]benzylacetate DeltaG(not equal) =80.8 +/-2.0 kJ/mol (380K), DeltaH(not equal) =60.7 +/-6.0 kcal/mol and DeltaS(not equal) =53 +/- 20 J/Kmol; (IV) 2-[N-Acetyl-N-(2-acetyloxybenzyl)amino]phenylacetate DeltaG(not equal) =77.0 +/-2.0 kJ/mol (370K), DeltaH(not equal) =65.3 +/-6.0 kJ/mol and DeltaS(not equal) =-32 +/- 20 J/Kmol. Substitution at positions 2 and 2' with bulky groups appears to be essential to freeze the gauche structure at room temperature and consequently, the main contribution to the barrier arises from the steric hindrance between these two groups. Structure I shows an anomalous behavior...

Neyman-Pearson Detection of Gauss-Markov Signals in Noise: Closed-Form Error Exponent and Properties

Sung, Youngchul; Tong, Lang; Poor, H. Vincent
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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The performance of Neyman-Pearson detection of correlated stochastic signals using noisy observations is investigated via the error exponent for the miss probability with a fixed level. Using the state-space structure of the signal and observation model, a closed-form expression for the error exponent is derived, and the connection between the asymptotic behavior of the optimal detector and that of the Kalman filter is established. The properties of the error exponent are investigated for the scalar case. It is shown that the error exponent has distinct characteristics with respect to correlation strength: for signal-to-noise ratio (SNR) >1 the error exponent decreases monotonically as the correlation becomes stronger, whereas for SNR <1 there is an optimal correlation that maximizes the error exponent for a given SNR.; Comment: To appear in the IEEE Transactions on Information Theory

How Much Information can One Get from a Wireless Ad Hoc Sensor Network over a Correlated Random Field?

Sung, Youngchul; Poor, H. Vincent; Yu, Heejung
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/03/2009 Português
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New large deviations results that characterize the asymptotic information rates for general $d$-dimensional ($d$-D) stationary Gaussian fields are obtained. By applying the general results to sensor nodes on a two-dimensional (2-D) lattice, the asymptotic behavior of ad hoc sensor networks deployed over correlated random fields for statistical inference is investigated. Under a 2-D hidden Gauss-Markov random field model with symmetric first order conditional autoregression and the assumption of no in-network data fusion, the behavior of the total obtainable information [nats] and energy efficiency [nats/J] defined as the ratio of total gathered information to the required energy is obtained as the coverage area, node density and energy vary. When the sensor node density is fixed, the energy efficiency decreases to zero with rate $\Theta({area}^{-1/2})$ and the per-node information under fixed per-node energy also diminishes to zero with rate $O(N_t^{-1/3})$ as the number $N_t$ of network nodes increases by increasing the coverage area. As the sensor spacing $d_n$ increases, the per-node information converges to its limit $D$ with rate $D-\sqrt{d_n}e^{-\alpha d_n}$ for a given diffusion rate $\alpha$. When the coverage area is fixed and the node density increases...

Single-Exclusion Number and the Stopping Redundancy of MDS Codes

Han, Junsheng; Siegel, Paul H.; Roth, Ron M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/12/2007 Português
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For a linear block code C, its stopping redundancy is defined as the smallest number of check nodes in a Tanner graph for C, such that there exist no stopping sets of size smaller than the minimum distance of C. Schwartz and Vardy conjectured that the stopping redundancy of an MDS code should only depend on its length and minimum distance. We define the (n,t)-single-exclusion number, S(n,t) as the smallest number of t-subsets of an n-set, such that for each i-subset of the n-set, i=1,...,t+1, there exists a t-subset that contains all but one element of the i-subset. New upper bounds on the single-exclusion number are obtained via probabilistic methods, recurrent inequalities, as well as explicit constructions. The new bounds are used to better understand the stopping redundancy of MDS codes. In particular, it is shown that for [n,k=n-d+1,d] MDS codes, as n goes to infinity, the stopping redundancy is asymptotic to S(n,d-2), if d=o(\sqrt{n}), or if k=o(\sqrt{n}) and k goes to infinity, thus giving partial confirmation of the Schwartz-Vardy conjecture in the asymptotic sense.; Comment: 12 pages, 1 figure. Submitted to IEEE Transactions on Information Theory

Large Deviations Analysis for the Detection of 2D Hidden Gauss-Markov Random Fields Using Sensor Networks

Sung, Youngchul; Poor, H. Vincent; Yu, Heejung
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 20/01/2008 Português
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The detection of hidden two-dimensional Gauss-Markov random fields using sensor networks is considered. Under a conditional autoregressive model, the error exponent for the Neyman-Pearson detector satisfying a fixed level constraint is obtained using the large deviations principle. For a symmetric first order autoregressive model, the error exponent is given explicitly in terms of the SNR and an edge dependence factor (field correlation). The behavior of the error exponent as a function of correlation strength is seen to divide into two regions depending on the value of the SNR. At high SNR, uncorrelated observations maximize the error exponent for a given SNR, whereas there is non-zero optimal correlation at low SNR. Based on the error exponent, the energy efficiency (defined as the ratio of the total information gathered to the total energy required) of ad hoc sensor network for detection is examined for two sensor deployment models: an infinite area model and and infinite density model. For a fixed sensor density, the energy efficiency diminishes to zero at rate O(area^{-1/2}) as the area is increased. On the other hand, non-zero efficiency is possible for increasing density depending on the behavior of the physical correlation as a function of the link length.; Comment: To appear in the Proceedings of the 2008 IEEE International Conference on Acoustics...

Perfect Z2Z4-linear codes in Steganography

Rifà-Pous, H.; Rifà, J.; Ronquillo, L.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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Steganography is an information hiding application which aims to hide secret data imperceptibly into a commonly used media. Unfortunately, the theoretical hiding asymptotical capacity of steganographic systems is not attained by algorithms developed so far. In this paper, we describe a novel coding method based on Z2Z4-linear codes that conforms to +/-1-steganography, that is secret data is embedded into a cover message by distorting each symbol by one unit at most. This method solves some problems encountered by the most efficient methods known today, based on ternary Hamming codes. Finally, the performance of this new technique is compared with that of the mentioned methods and with the well-known theoretical upper bound.; Comment: 5 pages, revised version

Evaluation of hβD-1 and hβD-2 levels in saliva of patients with oral mucosal diseases

Kucukkolbasi,H; Kucukkolbasi,S; Ayyildiz,HF; Dursun,R; Kara,H
Fonte: West Indian Medical Journal Publicador: West Indian Medical Journal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2013 Português
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OBJECTIVE: This study aimed to determine a possible correlation between oral mucosal disease and salivary concentrations of the antimicrobial peptides human beta-defensin-1 (hβD-1) and human betadefensin- 2 (hβD-2). METHOD: The present work focussed on the establishment of a reversed phase-high performance liquid chromatography (RP-HPLC) procedure to quantify human beta-defensins (hβD-1 and hβD-2) in saliva samples of patients with oral diseases such as lichen planus (n = 10), Behçet (n = 10) and recurrent apthous stomatitis (n = 10). RESULTS: Linear calibration range for hβD-1 and hβD-2 defensins was 1.67−200 µg mL-1 and 3.13− 100 µg mL-1 with R2 values of 0.9998 and 0.996, correspondingly. The concentration of beta-defensins in saliva was determined by comparing the peak areas of eluted hβD-1 and hβD-2 with that of their standards. The variation of the amount of beta-defensins was evaluated by comparisons of the results obtained from the patients with oral mucosal diseases before and after treatments and the control subjects. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.62 µg mL- 1 and 5.39 µg mL-1 for hβD-1 and 0.94 µg mL-1 and 3.13 µg mL-1 for hβD-2...