General contribution of nonspecific interactions to fluorescence intensity

Many chemical compounds, including nonfluorescent ones, induce changes in the fluorescence spectra of certain probes, such as berberine cation and Reichardt's betaine, both in the absence and the presence of solvent, that affect almost exclusively emission intensity. In this work, the application of fluorescence detection by intensity changes (FDIC) to HPLC and TLC chromatographic systems with fluorescence detectors has been studied. FDIC detection is of special interest in detecting nonfluorescent analytes, either in HPLC or in TLC mode. It does not involve covalent interactions, and the dielectric permittivity (epsilon) of the medium plays an important role. The balance between nonspecific and specific interactions produces either an increase or a decrease in fluorescence intensity. Therefore, the influence of chromatographic conditions and chemical structure of analytes on the sign and magnitude of fluorescence peaks for sample detection in HPLC and TLC systems has been discussed. In general, probe nature and concentration determine response and detection sensitivity for a given sample in TLC and HPLC. As solubility and fluorescence properties in solvents determine the operating conditions for a FDIC probe in HPLC mode, nature and flows of mobile phase and solvent are important for chromatographic response and detection sensitivity.     

Invariant polarimetric contrast parameters of light with Gaussian fluctuations in three dimensions

We propose a rigorous definition of the minimal set of parameters that characterize the difference between two partially polarized states of light whose electric fields vary in three dimensions with Gaussian fluctuations. Although two such states are a priori defined by eighteen parameters, we demonstrate that the performance of processing tasks such as detection, localization, or segmentation of spatial or temporal polarization variations is uniquely determined by three scalar functions of these parameters. These functions define a "polarimetric contrast" that simplifies the analysis and the specification of processing techniques on polarimetric signals and images. This result can also be used to analyze the definition of the degree of polarization of a three-dimensional state of light with Gaussian fluctuations in comparison, with respect to its polarimetric contrast parameters, with a totally depolarized light. We show that these contrast parameters are a simple function of the degrees of polarization previously proposed by Barakat [Opt. Acta 30, 1171 (1983)] and Set?l? et al. [Phys. Rev. Lett. 88, 123902 (2002)]. Finally, we analyze the dimension of the set of contrast parameters in different particular situations.     

Docking onto chromatin via the Saccharomyces cerevisiae Rad9 Tudor domain

An integrated cellular response to DNA damage is essential for the maintenance of genome integrity. Recently, post-translational modifications to histone proteins have been implicated in DNA damage responses involving the Rad9 family of checkpoint proteins. In budding yeast, methylation of histone H3 on lysine 79 (H3-K79me) has been shown to be required for efficient checkpoint signalling and Rad9 localization on chromatin. Here, we have used a rad9 Tudor mutant allele and cells mutated for Dot1, the H3-K79 methylase, to analyse the epistatic relationship between RAD9 and DOT1 genes regarding the DNA damage resistance and checkpoint activation pathways. Our results show that RAD9 is epistatic to DOT1 and suggest that it acts downstream of the Dot1 methylase in the damage resistance and checkpoint response. We have also found that the Tudor domain of Rad9 is necessary for in vitro binding to H3-K79me as well as Rad9 focal accumulation in response to DNA damage in vivo. In summary, our study demonstrates that the interaction between Rad9, via its Tudor domain, and methylated H3-K79 is required at two different steps of the DNA damage response, an early step corresponding to checkpoint activation, and a late step corresponding to DNA repair. The study further shows that the function of this interaction is cell cycle-regulated; the role in checkpoint activation is restricted to the G(1) phase and its role in DNA repair is restricted to G(2).     

Formation of Soy Protein Isolate Cold-set Gels: Protein and Salt Effects

ABSTRACT: The influence of protein and calcium concentration on soy protein cold-set gel formation and rheology has been investigated. Cold-set gels can be formed at soy protein concentrations from 6% to 9% and calcium concentrations from 10 to 20 mM. Gel properties can be modulated by changing the protein and/or CaCl₂ concentrations. An increase in CaCl₂ concentration from 10 to 20 mM increased gel opacity while an increase in protein concentration from 6% to 9% decreased opacity. Water-holding capacity improved with increasing protein concentration and decreasing CaCl₂ concentration. The elastic modulus (G') increased with protein and calcium chloride concentrations. Microscopy revealed an increase in the diameters of aggregates and pores as CaCl₂ concentration increased and as protein concentration decreased. Cold-set gels with a broad range of characteristics can be obtained from soy protein.     

Investigation into the removal of a formaldehyde-free easy care cross-linking agent from cotton and the potential for subsequent regeneration of lyocell-type fibres

1,2,3,4-Butane tetracarboxylic acid (BTCA)-treated cotton fabrics were immersed in alkali for increasing time periods and the effectiveness of alkali in removing the cross-linking agent was investigated by surface (X-ray photoelectron spectroscopy, XPS) analysis, attenuated total reflectance Fourier transform infrared spectroscopy and solubility in specific solvents. The cellulose yield after the chemical ‘stripping’ processes was established and the effect of the alkali treatments on the degree of polymerization of the resultant cellulose determined. Surface analyses and solubility tests suggested that the alkali alone could successfully remove the BTCA from the crease resist-treated cotton fabric and produced a commercially viable yield of cellulose.     

Cytocompatibility of titanium metal injection molding with various anodic oxidation post-treatments

Metal injection molding (MIM) is a near net shape manufacturing method that allows for the production of components of small to moderate size and complex shape. MIM is a cost-effective and flexible manufacturing technique that provides a large innovative potential over existing methods for the industry of implantable devices. Commercially pure titanium (CP-Ti) samples were machined to the same shape as a composite feedstock with titanium and polyoxymethylene, and these metals were injected, debinded and sintered to assess comparative biological properties. Moreover, we treated MIM-Ti parts with BIOCOAT®, BIODIZE® and BIOCER®, three different anodic oxidation techniques that treat titanium using acid, alkaline and anion enriched electrolytes, respectively. Cytocompatibility as well as morphological and chemical features of surfaces was comparatively assessed on each sample, and the results revealed that MIM-Ti compared to CP-Ti demonstrated a specific surface topography with a higher roughness. MIM-Ti and BIOCER® samples significantly enhanced cell proliferation, cell adhesion and cell differentiation compared to CP-Ti. Interestingly, in the anodization post-treatment established in this study, we demonstrated the ability to improve osseointegration through anionic modification treatment. The excellent biological response we observed with MIM parts using the injection molding process represents a promising manufacturing method for the future implantable devices in direct contact with bones.     

Modelling knowledge related to the allocation of modular jigs for part fixturing using fuzzy reasoning

One the problems a workholder designer faces in attempting to gain knowledge about the modelling of the “wear” in a positioning system by means of allocating positioning devices to each “virtual”locating point is that this knowledge is often verbalized by experts in an imprecise and uncertain way. Knowledge comes from technological know-how, and is developed through experience, personal habits and production-specific requirements. Nevertheless, current modelling of “expert knowledge” does not allow us to represent the different semantics (such as imprecision and uncertainty) that are related to it. In this paper, we present a method based on fuzzy reasoning that is able to support the modelling of these different knowledge semantics .     

Psychological implications of traumatic brain damage for the patient's family.

Discusses counseling to help families adapt to the behavioral and personality disturbances accompanying moderate to severe brain damage, namely those incurred in motor vehicle accidents. Families of brain-damaged patients often do not understand the nature and behavioral sequelae of the injury. Stresses in the family created by the patient's altered behavior can be compounded by unrealistically optimistic expectations. Family reactions to the sequelae go through 6 stages, as pleasure at the patient's return home is replaced by bewilderment and anxiety when energy and optimism wear thin; this stage is often followed by guilt, depression, despair, mourning, and reorganization and emotional disengagement. Psychological intervention can help families negotiate these stages by helping them to understand the nature and effects of the injury, facilitating more realistic expectations, and helping them work through the conflicts and pain engendered by the injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microwave V-I transmission matrix formalism for the analysis of photonic circuits: application to fiber Bragg gratings

We propose the use of V-I matrices well known in microwave engineering to the analysis of photonic devices, especially those based on multilayer dielectrics. As an application we present a novel fast effective index method for the analysis of fiber Bragg gratings based on the use of V-I transmission matrices. It combines the exactitude of traditional effective index methods and the speed of coupled-mode methods.