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1.
Int Immunol ; 25(6): 345-52, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23382353

RESUMO

A methodology based on the representation of each amino acid of a protein sequence by the electron-ion interaction potential and subsequent analysis by signal processing was used to determine the characteristic or common frequency (in Hz) that reflects the biological activity shared among phosphocholine (PC)-binding antibodies. The common frequency for the variable portion of the heavy chain (VH) of the PC-specific antibodies is found to be at f = 0.37 Hz. The VH sequences of the PC-binding antibodies exhibit three subsites for the PC moiety where hypervariable region 2 (CDR2) plays a role in the interaction with the phosphate group. Mutations in this VH region have an impact on the ability of mutant variants to bind PC and its carrier molecule, as well as on the characteristic frequency shift toward f = 0.12 Hz for mutants failing to bind both hapten and carrier. The VH sequence of mutants that retain the ability to bind PC still shows f = 0.37 Hz, suggesting that this frequency determines PC binding. However, this statement was not confirmed as mutation in another PC subsite impairs PC binding but retains both the phosphate-group recognition and the frequency at f = 0.37 Hz. Herein, this finding is discussed to promote the idea that the VH sequence of the PC-binding antibodies encodes the subsite for phosphate-group binding as a dominant functional activity and that only CDR2 of the T15-idiotype antibodies together with FR3 region form an autonomous self-association function represented by the T15VH50-73 peptide with f = 0.37±0.05 Hz. Thus, these data confirmed that T15VH50-73 peptide might be used in superantibody technology.


Assuntos
Anticorpos/imunologia , Idiotipos de Imunoglobulinas/química , Idiotipos de Imunoglobulinas/imunologia , Região Variável de Imunoglobulina/química , Região Variável de Imunoglobulina/imunologia , Fosforilcolina/imunologia , Animais , Sítios de Ligação/imunologia , Idiotipos de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Camundongos
2.
J Res Med Sci ; 17(11): 1027-32, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23833576

RESUMO

OBJECTIVE: We investigated the effects of bisoprolol and losartan on subjects with essential hypertension, by conducting heart rate variability (HRV) analysis of ECG signals. Our intention was to establish the set of linear and nonlinear heart rate variability parameters, which could be used as a noninvasive markers in the treatment of hypertension. MATERIALS AND METHODS: Sixty subjects with essential hypertension included in this study were divided in two groups. During the four weeks medical treatment, the first group was administered with daily oral dose of 5 mg of bisoprolol and the second with daily oral dose of 50 mg of losartan. We recorded ECG signals, and performed HRV analysis of consecutive RR time intervals, before and after a month of pharmacological therapy. RESULTS: IN THE CASE OF BISOPROLOL, STATISTICALLY THE MOST SIGNIFICANT CHANGES OF HRV PARAMETERS WERE: TP (1814.1 ± 1731.3 ms(2) vs. 761.3 ± 725.0 ms(2), P < 0.0001), RR (870.2 ± 105.7 ms vs. 1027.2 ± 150.0 ms, P < 0.0001), HR (70.81 ± 8.42 bp/min vs. 60.10 ± 9.52 bp/min, P < 0.0001). In the case of losartan, the most significant changes were: SDNN (43.16 ± 17.27 ms vs. 237.98 ± 118.54 ms, P = 0.002), rmSDD (27.09 ± 18.27 ms vs. 46.82 ± 37.71 ms, P = 0.003), SD2 (55.18 ± 20.6 vs. 70.67 ± 26.12, P < 0.019) and DF2 (0.69 ± 0.21 vs. 0.86 ± 0.25, P < 0.014). CONCLUSION: Effects of bisoprolol and losartan were especially manifested among the set of linear HRV parameters. As a consequence of effect of losartan, we singled out the nonlinear parameters SD2 and DF2.

3.
Conf Proc IEEE Eng Med Biol Soc ; 2009: 4731-4, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19964840

RESUMO

A protein's biological function is encrypted within its primary structure. Nevertheless, revealing protein function from analysis of its primary structure is still unsolved problem. In this article we present a new methodology for determining functionally significant amino acid residues in proteins sequences, which is based on time-frequency signal analysis and Smoothed Pseudo Wigner Ville distribution (SPWV). This investigation is the extension of the Resonant Recognition Model (RRM) approach designed for structure-function analysis of proteins and DNA. The RRM is based on the finding that there is a significant correlation between spectra of the numerical presentation of amino acids and their biological activity. The RRM assumes that the selectivity of protein interactions is based on the resonant electromagnetic energy transfer at the specific frequency for each interaction. In this study Cytochrome C, Glucagon, and Hemoglobin proteins were used as the protein examples. By incorporating the SPWV distribution in the RRM, we can define the active regions along the protein molecule. In addition, it was also shown that our computational predictions are corresponding closely with the experimentally identified locations of the active/binding sites for the selected protein examples.


Assuntos
Biologia Computacional/métodos , Modelos Teóricos , Proteínas/química , Sequência de Aminoácidos , Humanos , Relação Estrutura-Atividade
4.
J Am Chem Soc ; 130(45): 14958-9, 2008 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-18921981

RESUMO

We report an approach for growing aligned ZnO nanowire arrays with a high degree control over size, orientation, dimensionality, uniformity, and possibly shape. Our method combines e-beam lithography and a low temperature hydrothermal method to achieve patterned and aligned growth of ZnO NWs at <100degreesC on general inorganic substrates, such as Si and GaN, without using catalyst. This approach opens up the possibility of applying ZnO nanowires as sensor arrays, piezoelectric antenna arrays, two-dimensional photonic crystals, IC interconnects, and nanogenerators.


Assuntos
Gálio/química , Nanofios/química , Silício/química , Óxido de Zinco/química , Catálise , Temperatura Baixa , Cristalização , Polimetil Metacrilato/química , Difração de Raios X
5.
Nano Lett ; 6(2): 263-6, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16464047

RESUMO

Rectifying diodes of single nanobelt/nanowire-based devices have been fabricated by aligning single ZnO nanobelts/nanowires across paired Au electrodes using dielectrophoresis. A current of 0.5 microA at 1.5 V forward bias has been received, and the diode can bear an applied voltage of up to 10 V. The ideality factor of the diode is approximately 3, and the on-to-off current ratio is as high as 2,000. The detailed IV characteristics of the Schottky diodes have been investigated at low temperatures. The formation of the Schottky diodes is suggested due to the asymmetric contacts formed in the dielectrophoresis aligning process.


Assuntos
Ouro/química , Nanotubos/química , Óxido de Zinco/química , Eletrodos , Eletroforese , Nanotecnologia/instrumentação , Nanotecnologia/métodos , Tamanho da Partícula , Sensibilidade e Especificidade , Silício/química , Dióxido de Silício/química , Propriedades de Superfície
6.
Conf Proc IEEE Eng Med Biol Soc ; Suppl: 6509-12, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17959438

RESUMO

Previously, electrocardiogram (ECG) signals have been analyzed in either a time-indexed or spectral form. The reality, is that the ECG and all other biological signals belong to the family of multicomponent nonstationary signals. Due to this reason, the use of time-frequency analysis can be unavoidable for these signals. The Husimi and Wigner distributions are normally used in quantum mechanics for phase space representations of the wavefunction. In this paper, we introduce the Husimi distribution (HD) to analyze the normal and abnormal ECG signals in time-frequency domain. The abnormal cardiac signal was taken from a patient with supraventricular arrhythmia. Simulation results show that the HD has a good performance in the analysis of the ECG signals comparing with the Wigner-Ville distribution (WVD).


Assuntos
Arritmias Cardíacas/fisiopatologia , Teoria Quântica , Processamento de Sinais Assistido por Computador , Eletrocardiografia/métodos , Humanos
7.
J Am Chem Soc ; 127(47): 16376-7, 2005 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-16305207

RESUMO

Large-scale Ni-doped ZnO nanowire (NW) arrays are grown. The electrical conductivity of a single Ni-doped ZnO NW has been increased for 30 times. The photoluminescence (PL) spectrum of the doped ZnO NWs has a red shift, suggesting possible doping induced band edge bending. The doped NW arrays could be the basis for building integrated nanoscale transistors, sensors, and photodetectors.

8.
Phys Med Biol ; 48(15): N213-21, 2003 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-12953917

RESUMO

The reflection of x-rays from a half space is studied within the framework of a model that assumes multiple isotropic scattering of photons without energy loss. An exactly solvable analytical expression for the angular distribution of reflected photons is derived. The range of validity of the model was determined by the Monte Carlo simulation thereby incorporating energy loss and angular dependences. For water as a scatterer, in the energy range from 10 to 60 keV, which is often used in x-ray diagnostics, the two approaches differ by at most 5%. The analytic results, confirmed by the Monte Carlo simulation, show that the angular distribution of reflected photons for energies greater than 30 keV--where multiple scattering events dominate--may be represented by a cosine law, within a few per cent of accuracy.


Assuntos
Algoritmos , Transferência de Energia , Radiometria/métodos , Espalhamento de Radiação , Água/química , Raios X , Exposição Ocupacional/análise , Fótons , Radiologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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