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The letter to the editor presents methodological issues about the search strategy, adequate reporting of meta-analysis, and statistical details of the referred article.
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Frutas , Verduras , Humanos , Síndrome Metabólico , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
Surface enhancement Raman scattering (SERS) of two tautomer of thiobarbituric acid was obtained using silver and gold nanoparticles. Large band enhancement in the region of the ν(C=S), ν(C=C), δ(CH2), and δ(CNH) vibrational modes was found. Natural bond analysis of the tautomer species revealed expressive values of charge transfer, principally from lone pair electron orbitals of the S, N, and O atoms. Complete vibrational assignment was done for the two tautomers using the B3LYP/6-311+G (d, p) procedure, band deconvolution analysis, and from a rigorous interpretation of the normal modes matrix. The calculated spectra agree well with the experimental ones.
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Tiobarbitúricos/química , Modelos Moleculares , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , EstereoisomerismoRESUMEN
Surface-enhanced Raman scattering (SERS) was used to study the interactions of the normal modes of the bis(diethyldithiocarbamate)zinc(II) complex, [Zn(DDTC)2], on nano-structured silver surfaces. The electronic spectrum of this complex was measured and the charge transfer bands were assigned through the TD-PBE1PBE procedure. To see the electronic dispersion, the Mulliken electronic charges were calculated for each normal mode and correlated with the SERS effect. Full assignment of the SERS spectra was also supported by carefully analysis of the distorted geometries generated by the normal modes.
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Complejos de Coordinación/química , Ditiocarba/química , Zinc/química , Electrones , Modelos Moleculares , Espectrofotometría Ultravioleta , Espectrometría RamanRESUMEN
Theoretical and experimental bands have been assigned for the Fourier Transform Infrared (FT-IR) and Fourier Transform Raman (FT-Raman) spectra of the bis-(diethydithiocarbamate)Zn(II) complex, [Zn(DDTC)(2)]. The calculations and spectra interpretation have been based on the DFT/B3LYP method, infrared and Raman second derivative spectra as well as band deconvolution analysis. To assign the metal-ligand normal modes the deviation percentage of the geometrical parameters was used. Results confirms a pseudo tetrahedral structure around the Zn(II) cation. The calculated infrared and Raman spectra has an excellent agreement with the experimental spectra. The Natural Bond Orbital analysis (NBO) was carried out as a way to study the Zn(II) hybridization leading to the pseudo tetrahedral geometry of the framework of the [Zn(DDTC)(2)] complex, and to study also which are the donor NBO and the acceptor NBO in meaningful charge transfer through the Second Order Perturbation Theory Analysis of Fox Matrix in NBO basis.
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Complejos de Coordinación/química , Ditiocarba/química , Zinc/química , Modelos Moleculares , Teoría Cuántica , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría RamanRESUMEN
Theoretical and experimental bands have been assigned for the Fourier Transform Infrared (FT-IR) and FT-Raman spectra of the bis(diethydithiocarbamate)Cu(II) complex, [Cu(DDTC)(2)]. The calculations and spectra interpretation have been based on the DFT/B3LYP method, infrared and Raman second derivative spectra, and band deconvolution analysis. To better assign the metal-ligand normal modes in the spectral region of low energy, the deviation percentage of the geometrical parameters was used, with values from the interpretation of the normal modes of L matrix. Results indicate a planar structure around the Cu(II) cation. The calculated infrared and Raman spectra, based on the proposed geometrical structure of the bis(diethyldithiocarbamate)copper(II) complex, agreed with the experimental spectra.
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Complejos de Coordinación/química , Cobre/química , Ditiocarba/química , Complejos de Coordinación/síntesis química , Ditiocarba/síntesis química , Modelos Moleculares , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría RamanRESUMEN
The aspartateguanidoacetatenickel (II) complex, [Ni(Asp)(GAA)], was synthesized and structural analysis was performed by means of the experimental methods: determination of the C, H, N and O contents, thermogravimetry, infrared and Raman spectroscopy. DFT:B3LYP/6-311G(d, p) calculations have been performed giving optimized structure and harmonic vibrational wavenumbers. Second derivative of the FT-infrared, FT-Raman and Surface Raman Enhanced Scattering (SERS) spectra, and band deconvolution analysis were also performed. Features of the FT-infrared, FT-Raman and SERS confirmed theoretical structure prediction. Full assignment of the vibrational spectrum was also supported by a carefully analysis of the distorted geometries generated by the normal modes. The Natural Bond Orbital analysis (NBO) was also carried out as a way to study the Ni (II) hybridization leading to the pseudo planar geometry of the framework, and the extension of the atomic N and O hybrid orbital of the different amino acids in the bond formation. Bands of charge transfer and d-d transitions were assigned in the UV-Vis spectrum.
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Ácido Aspártico/química , Electrones , Modelos Moleculares , Níquel/química , Compuestos Organometálicos/química , Teoría Cuántica , Espectrometría Raman , Vibración , Conformación Molecular , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , TermodinámicaRESUMEN
The 2-diazo-5,5-dimethyl-cyclohexane-1,3-dione (3) was synthesized and the FT-IR/Raman spectra were measured with the purpose of obtain a full assignment of the vibrational modes. Singular aspects concerning the -CNN oscillator are discussed in view of two strong bands observed in the region of 2300-2100 cm(-1) in both, Infrared and Raman spectra. The density functional theory (DFT) was used to obtain the geometrical structure and for assisting in the vibrational assignment joint to the traditional normal coordinate analysis (NCA). The observed wavenumbers at 2145 (IR), 2144(R) are assigned as the coupled nu(NN)+nu(CN) vibrational mode with higher participation of the NN stretching. A 2188 cm(-1) (IR) and at 2186 cm(-1) (R) can be assigned as a overtone of one of nu(CC) normal mode or to a combination band of the fundamentals delta(CCH) found at 1169 cm(-1) and the delta (CCN) found at 1017 cm(-1) enhanced by Fermi resonance.
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Compuestos Azo/química , Ciclohexanos/química , Programas Informáticos , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Simulación por Computador , Modelos Químicos , Conformación Molecular , VibraciónRESUMEN
The structure of [Co(gly)(2)(OH)(2)].1.5(H(2)O) was solved by X-ray diffraction. It crystallizes in the space group P-1, with two independent dimmers in the unit cell. The results for the calculated vibrational spectra are in good agreement with the experimental one. The infrared spectrum and ab initio calculations are consistent with the crystallographic results.
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Cobalto/química , Glicina/análogos & derivados , Glicina/química , Compuestos Organometálicos/síntesis química , Carbono/análisis , Cristalización/métodos , Glicina/síntesis química , Hidrógeno/análisis , Modelos Moleculares , Estructura Molecular , Nitrógeno/análisis , Oxidación-Reducción , Oxígeno/análisis , Análisis Espectral/métodos , VibraciónAsunto(s)
Anticuerpos Antiprotozoarios/análisis , Entamoeba histolytica/inmunología , Entamebiasis/epidemiología , Inmunoglobulina A/análisis , Proteínas y Péptidos Salivales/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Niño , Preescolar , Estudios Transversales , Entamebiasis/diagnóstico , Entamebiasis/inmunología , Estudios de Evaluación como Asunto , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Prevalencia , Salud RuralRESUMEN
BACKGROUND: Amebiasis still remains as a major public health problem in the world. It is one of the most common reasons for medical consult. There are more than half a million cases of amebiasis just at the Mexican Institute of the Social Security. There is still a lack of epidemiologic information on amebiasis in Mexico. AIM: To describe the secular trend fro amebiasis and for amebic liver abscess in the Mexican population, as well as in those covered by IMSS Solidaridad. METHOD: An ecologic trend study was carried on. Incidence rate of amebiasis in all of its forms of presentation, and of amebic liver abscess, were plotted against each year for the 1986-1994 period. RESULTS: Amebiasis incidence in all of its forms of presentation showed a stable trend in this period, as it was seen with amebic liver abscess. Amebiasis is more common in the first years of life. On the contrary, amebic liver abscess showed an inverted 'J' pattern; its occurrence is higher in the extreme years of life. Fatality rates have shown a descendent trend. CONCLUSIONS: Amebiasis reflects socioeconomic conditions in Mexico and the fact that Mexican is still an endless culture. There is a need to promote health education, better diagnostic procedures and detection of asymptomatic carriers. Health policies for mothers that are asymptomatic carriers should be reviewed, due to the high rates of amebiasis and amebic liver abscess in children under one year of age.
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Amebiasis/epidemiología , Absceso Hepático Amebiano/epidemiología , Salud Pública , Adolescente , Adulto , Factores de Edad , Anciano , Amebiasis/prevención & control , Portador Sano/epidemiología , Niño , Preescolar , Femenino , Educación en Salud , Humanos , Lactante , Recién Nacido , Absceso Hepático Amebiano/prevención & control , Masculino , México/epidemiología , Persona de Mediana Edad , Factores SocioeconómicosRESUMEN
This paper describes studies on the processivity of an [alpha]-type DNA polymerase from maize (Zea mays L.) embryonic axes, designated as DNA polymerase 2. Using poly(dA)/oligo(dT) as template, DNA polymerase 2 has a processivity of 18 ([plus or minus]5) nucleotides incorporated, a value much lower than that found for wheat [alpha]-type DNA polymerase (P. Laquel, S. Litvak, M. Castroviejo [1993] Plant Physiol 102: 107-114). Conditions that maximally stimulate enzyme activity, such as 100 mM KCl and 12 mM Mg2+, are strongly inhibitory of processivity and cause the enzyme to become distributive under these conditions. Optimal concentrations for processivity are 10 mM KCl and 1 to 2 mM Mg2+. Both enzyme activity and processivity were found to be similar at different Mn2+ concentrations. Both DNA polymerase 2 activity and processivity are greatly reduced by spermine and N-ethylmaleimide. A distinguishing feature of processivity in DNA polymerase 2 was the response to ATP, which not only stimulated processivity by more than 2-fold, but also produced a distinctive pattern in which the enzyme seemed to pause every 10 nucleotides, reaching a value of 40 to 50 nucleotides incorporated. This pattern was observed in some, but not all, heparin-Sepharose fractions with enzyme activity, suggesting the possibility of different DNA polymerase 2 complexes.
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Amebiasis is one of the most common parasite-related diseases and one of those with the greatest impact on health. At the Instituto Mexicano del Seguro Social (Mexican Institute of Social Security-IMSS) approximately half a million cases per year are currently treated. Of these, more than 2500 correspond to the form which invades the liver. Within the process of epidemiologic transition which Mexico is undergoing, a progressive reduction has been observed in incidence of, and mortality due to, invading amebiasis in all its clinical forms. In turn, there is a significant decrease in its fatality rate. The social and economic development and improved sanitary conditions observed in Mexico, particularly in the second half of this century, may have conditioned this process. The improvement in availability, accessibility and utilization of medical care services could also explain the reduction which has been noted in its fatality rate and mortality. The model for epidemiologic transition proposed by Omran and adapted for Mexico by Frenk, offers a plausible explanation for the changes observed in the occurrence and mortality of invading amebiasis in Mexico.
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Amebiasis/epidemiología , Amebiasis/mortalidad , Amebiasis/fisiopatología , Humanos , Incidencia , México/epidemiologíaRESUMEN
The authors present a patient with intestinal lymphangiectasis discussing the pathophysiology, diagnosis and immunologic treatment instituted which was with mebendazole, sulfazalosopyridine and oral calcium. Immunoglobulins and T and B leukocytes showed increase together with clinical improvement in the diarrheal picture.
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Bencimidazoles/uso terapéutico , Inmunosupresores/uso terapéutico , Linfangiectasia Intestinal/tratamiento farmacológico , Mebendazol/uso terapéutico , Enteropatías Perdedoras de Proteínas/tratamiento farmacológico , Sulfanilamidas/uso terapéutico , Sulfapiridina/uso terapéutico , Preescolar , Humanos , Inmunoterapia , Linfangiectasia Intestinal/diagnóstico por imagen , Linfangiectasia Intestinal/dietoterapia , Masculino , RadiografíaRESUMEN
The morphology of the intestinal mucosa was reviewed using light microscopy and transmission electron microscopy from a two year-old male patient with protein losing primary intestinal lyphangiectasis. Diagnostic studies ruled out recognized forms of secondary intestinal lymphangiectasia (e.g cardiac, hepatic, renal diseases or lymphoreticular cancer). Furthermore, certain features distinguish this patient from the secondary type: decreased immunoglobulin and albumin levels, lymphocytopenia, chylous ascitis and delated lymphatics on small-bowel biopsy.