Dispersion of gamma-Alumina Nano-Sized Spherical Particles in a Calamitic Liquid Crystal. Study and Optimization of the Confinement Effects

We report an experimental study on confined systems formed by butyloxybenzylidene octylaniline liquid crystal (4O.8) + gamma-alumina nanoparticles. The effects of the confinement in the thermal and dielectric properties of the liquid crystal under different densities of nanoparticles is analyzed by means of high resolution Modulated Differential Scanning Calorimetry (MDSC) and broadband dielectric spectroscopy. First, a drastic depression of the N-I and SmA-N transition temperatures is observed with confinement, the more concentration of nanoparticles the deeper this depression is, driving the nematic range closer to the room temperature. An interesting experimental law is found for both transition temperatures. Second, the change in shape of the heat capacity peaks is quantified by means of the full width half maximum (FWHM). Third, the confinement does not noticeably affect the molecular dynamics. Finally, the combination of nanoparticles and the external applied electric field tends to favor the alignment of the molecules in metallic cells. All these results indicate that the confinement of liquid crystals by means of gamma-alumina nanoparticles could be optimum for liquid crystal-based electrooptic devices.

Efeito da suplementação dietética com L-glutamina na sepse abdominal induzida em rato

Após o estímulo deflagrador de um trauma ou infecção, a liberação de citocinas na circulação sanguínea desempenha um importante papel efetor e também modulador da resposta imune sistêmica. Essas citocinas podem ser pró-inflamatórias, que estimulam a liberação de diversos tipos celulares e de outras citocinas, como fator de necrose tumoral-alfa (TNF-α), interleucina 1 (IL-1), IL-2, IL-6, IL-8, IL-12 e interferon-gama (INF-); ou citocinas com efeitos antiinflamatórios, que inibem o processo inflamatório, em parte pela redução da produção de diversas citocinas que regulam positivamente a resposta, minimizando o comprometimento orgânico resultante, como IL-4, IL-10, IL-13. A L-glutamina é o aminoácido mais abundante no organismo, com importante papel no metabolismo protéico. Sua ação trófica sobre a mucosa do intestino delgado é bastante conhecida, o que o torna componente essencial para a manutenção estrutural e funcional do intestino. O objetivo deste trabalho foi avaliar o efeito da suplementação dietética com L-glutamina na modulação da resposta inflamatória em animais submetidos a sepse abdominal induzida por ligadura e perfuração cecal. Foram utilizados 24 ratos Wistar machos adultos, com peso inicial entre 200 e 230 g, distribuídos em três grupos, cada um com oito animais, da seguinte forma: grupo I (controle) submetidos a operação simulada (laparotomia e manipulação de alças intestinais); grupo II submetidos a laparotomia, com indução de sepse abdominal; e grupo III receberam suplementação dietética com L-glutamina por sete dias e, após, foram submetidos a indução de sepse abdominal. Foram coletadas amostras sanguíneas de todos os animais antes (tempo 0) e duas e quatro horas (tempos 1 e 2) após a indução da sepse abdominal. Foram verificados o número de leucócitos, a dosagem da concentração plasmática de citocinas pró- e antiinflamatórias (INF-γ, IL-6 e IL-10) e análise microbiológica de líquido peritoneal. A glicemia apresentou aumento significativo em todos os grupos, comparando-os ao início e ao final do experimento (p<0,05). No que concerne à IL-10, observou-se aumento significativo nos animais do grupo III entre os tempos 0 e 2, e entre os tempos 1 e 2 (p=0,0331 e p=0,0155, respectivamente). Não se observou qualquer outra diferença ao serem analisadas as demais citocinas (IFN- e IL-6), em todos os grupos e em todos os momentos analisados. Nossos achados sugerem que a suplementação dietética com L-glutamina em animais submetidos à indução de sepse abdominal com modelo CLP parece potencializar a resposta antiinflamatória, aumentando a concentração plasmática de IL-10, enquanto as concentrações de INF-γ e IL-6 não apresentaram variação significativa.

Two Glass Transitions Associated to Different Dynamic Disorders in the Nematic Glassy State of a Non-Symmetric Liquid Crystal Dimer Dopped with gamma-Alumina Nanoparticles

In the present work, the nematic glassy state of the non-symmetric LC dimer -(4-cyanobiphenyl-4-yloxy)--(1-pyrenimine-benzylidene-4-oxy) undecane is studied by means of calorimetric and dielectric measurements. The most striking result of the work is the presence of two different glass transition temperatures: one due to the freezing of the flip-flop motions of the bulkier unit of the dimer and the other, at a lower temperature, related to the freezing of the flip-flop and precessional motions of the cyanobiphenyl unit. This result shows the fact that glass transition is the consequence of the freezing of one or more coupled dynamic disorders and not of the disordered phase itself. In order to avoid crystallization when the bulk sample is cooled down, the LC dimer has been confined via the dispersion of -alumina nanoparticles, in several concentrations.

Effects of gamma radiation on nutritional and microbial quality of Pampus chinensis (Euphrasen 1788)

To evaluate the efficiency of gamma radiation in combination with low temperature Chinese pomfret, Pampus chinensis were preserved by the treatment of different doses of gamma radiation (3, 5 and 8 KGy) at freezing temperature (-20°C) during 90 days of storage period. Quality assessments for fish were carried out at an interval of 15 days during the storage period. Quality assessments were done by organoleptic, chemical (Total Volatile Nitrogen, TVN and Trimethylamine, TMA) and microbiological (Total Bacterial Count, TBC and Total Mould Count, TMC) evaluation. From the analysis of all parameters, maximum shelf-life was observed for irradiated (8 KGy) sample. It remained acceptable up to 75 days and that was the highest duration among 4 types of samples.

beta gamma-CAT, a non-lens beta gamma-crystallin and trefoil factor complex from amphibian skin secretions, caused endothelium-dependent myocardial depression in isolated rabbit hearts

Previous in vivo study demonstrated that beta gamma-CAT, a newly identified non-lens beta gamma-crystallin and trefoil factor complex from frog Bombina maxima skin secretions, possessed potent lethal toxicity on mammals resulted from hypotension and cardi

Melanoma cell growth inhibition by beta gamma-CAT, which is a novel non-lens betagamma-crystallin and trefoil factor complex from frog Bombina maxima skin

In vertebrates, non-lens beta gamma-crystallins are widely expressed in various tissues but their functions are unknown. The molecular mechanisms of trefoil factors, initiators of mucosal healing and being greatly involved in tumorigenesis, have remained

Acute toxicity of beta gamma-CAT, a naturally existing non-lens beta gamma-crystallin and trefoil factor complex from frog Bombina maxima skin secretions

In vertebrates, non-lens beta gamma-crystallins are widely expressed in various tissues, but their functions are unknown. The molecular mechanisms of trefoil factors, initiators of mucosal healing and being greatly involved in tumorigenesis, have remained

Preservation of Bombay duck (Harpodon nehereus) and Rohu (Labeo rohita) by gamma irradiation

The gamma irradiation procedures for preservation of Bombay duck and rohu were studied in collaboration with Bhabha Atomic Research Centre, Bombay. Irradiation at 0.1 M rad extended the storage life of Bombay duck to 20-22 days at 0-2°C due to partial destruction of spoilage organisms as against rapid deterioration of un-irradiated samples within 5-6 days. In the case of the fresh water fish, rohu, the storage life was enhanced by about 7-10 days by the same dose of irradiation over the control under identical storage condition. In all the cases, empirical relations were worked out between organoleptic rating and total volatile nitrogen.

Diversification in utilisation of trash fish by gamma irradiation

Radiation pasteurisation enhances the shelf stability of trash fish varieties and enables the grading of fish depending upon the freshness quality. As against the ice-chilled fish which spoils within 8-10 days, exposure to 100 Krad and storage at ice temperature helps in maintaining the quality in Grade I, II or III up to 10, 20 or 25 days respectively. The improvement in quality thus provides scope for greater utilisation of trash fish for various secondary products.