Antimicrobial activity of AgCl embedded in a silica matrix on cotton fabric

An antimicrobial finishing for cotton fabric was prepared from commercial (iSys AG, Germany) silver chloride (Ag) dispersed at different concentrations in a reactive organic–inorganic binder (RB) (iSys MTX (CHT, Germany). Pad-dry-cure and exhaustion methods were used for the sols application, giving Ag-RB coating with Ag concentration from ca. 48 to ca. 290 ppm on the cotton fabric. The presence of silver on the cotton finishes was confirmed by measuring its concentration in the fabrics with the help of inductively coupled plasma mass spectroscopy (ICP-MS). The morphology of the finished fabrics was investigated by SEM, while their composition was established from EDXS measurements combined with the results of FT-IR spectral analysis. The antimicrobial activity of variously treated cotton fabrics was assessed before and after repetitive (up to 10×) washing by the application of standard tests: for the fungi Aspergillus niger (ATCC 6275) and Chaetomium globosum (ATCC 6205) by the modified DIN 53931 standard method, while the presence of Gram-negative bacterium Escherichia coli (ATCC 25922) was followed by using ISO 20645:2004 (E) and AATCC 100-1999 standard methods. Results revealed that the antimicrobial activity of the coatings strongly depended on the concentration of Ag in the corresponding Ag-RB dispersions, indirectly depending on the preparation method (pad-dry-cure vs. exhaustion) and that the Ag-RB coatings were more effective for bacteria than for fungi. The Ag concentrations on the cotton fabrics achieved by the pad-dry-cure method (48 and 52 ppm) were not sufficient to impart satisfactory antifungal activity to the cotton fabrics, though they assured excellent reduction of the bacterium E. coli (98–100%). A minimal inhibitory concentration of Ag in the coating providing a sufficient bacterial reduction of 60% was ca. 24 ppm. Effective antifungal activity was achieved only by applying the exhaustion method, enabling high initial Ag concentration in the Ag-RB coating (>100 ppm). The antibacterial activity depended on the washing treatment. No antifungal activity was noted for washed cotton fabric, even those with highly concentrated Ag (290 ppm) in the Ag-RB coating, but a 94% bacterial reduction was obtained for the corresponding cotton fabric, after 10 repetitive washings, corroborated by the Ag concentration on washed fabric of about 65 ppm.     

Genetical genomic determinants of alcohol consumption in rats and humans

Background

We have used a genetical genomic approach, in conjunction with phenotypic analysis of alcohol consumption, to identify candidate genes that predispose to varying levels of alcohol intake by HXB/BXH recombinant inbred rat strains. In addition, in two populations of humans, we assessed genetic polymorphisms associated with alcohol consumption using a custom genotyping array for 1,350 single nucleotide polymorphisms (SNPs). Our goal was to ascertain whether our approach, which relies on statistical and informatics techniques, and non-human animal models of alcohol drinking behavior, could inform interpretation of genetic association studies with human populations.

Results

In the HXB/BXH recombinant inbred (RI) rats, correlation analysis of brain gene expression levels with alcohol consumption in a two-bottle choice paradigm, and filtering based on behavioral and gene expression quantitative trait locus (QTL) analyses, generated a list of candidate genes. A literature-based, functional analysis of the interactions of the products of these candidate genes defined pathways linked to presynaptic GABA release, activation of dopamine neurons, and postsynaptic GABA receptor trafficking, in brain regions including the hypothalamus, ventral tegmentum and amygdala. The analysis also implicated energy metabolism and caloric intake control as potential influences on alcohol consumption by the recombinant inbred rats. In the human populations, polymorphisms in genes associated with GABA synthesis and GABA receptors, as well as genes related to dopaminergic transmission, were associated with alcohol consumption.

Conclusion

Our results emphasize the importance of the signaling pathways identified using the non-human animal models, rather than single gene products, in identifying factors responsible for complex traits such as alcohol consumption. The results suggest cross-species similarities in pathways that influence predisposition to consume alcohol by rats and humans. The importance of a well-defined phenotype is also illustrated. Our results also suggest that different genetic factors predispose alcohol dependence versus the phenotype of alcohol consumption.     

Circulation and distribution of gold nanoparticles and induced alterations of tissue morphology at intravenous particle delivery

Kinetics, biodistribution, and histological studies were performed to evaluate the particle‐size effects on the distribution of 15 nm and 50 nm PEG‐coated colloidal gold (CG) particles and 160 nm silica/gold nanoshells (NSs) in rats and rabbits. The above nanoparticles (NPs) were used as a model because of their importance for current biomedical applications such as photothermal therapy, optical coherence tomography, and resonance‐scattering imaging. The dynamics of NPs circulation in vivo was evaluated after intravenous administration of 15 nm CG NPs to rabbit, and the maximal concentrations of gold were observed 15–30 min after injection. Rats were injected in the tail vein with PEG‐coated NPs (about 0.3 mg Au/kg rats). 24 h after injection, the accumulation of gold in different organs and blood was determined by atomic absorption spectroscopy. In accordance with the published reports, we observed 15 nm particles in all organs with rather smooth distribution over liver, spleen and blood. By contrast, the larger NSs were accumulated mainly in the liver and spleen. For rabbits, the biodistribution was similar (72 h after intravenous injection). We report also preliminary data on the light microscopy and TEM histological examination that allows evaluation of the changes in biotissues after gold NPs treatment. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ancestral Vascular Lumen Formation via Basal Cell Surfaces

The cardiovascular system of bilaterians developed from a common ancestor. However, no endothelial cells exist in invertebrates demonstrating that primitive cardiovascular tubes do not require this vertebrate-specific cell type in order to form. This raises the question of how cardiovascular tubes form in invertebrates? Here we discovered that in the invertebrate cephalochordate amphioxus, the basement membranes of endoderm and mesoderm line the lumen of the major vessels, namely aorta and heart. During amphioxus development a laminin-containing extracellular matrix (ECM) was found to fill the space between the basal cell surfaces of endoderm and mesoderm along their anterior-posterior (A-P) axes. Blood cells appear in this ECM-filled tubular space, coincident with the development of a vascular lumen. To get insight into the underlying cellular mechanism, we induced vessels in vitro with a cell polarity similar to the vessels of amphioxus. We show that basal cell surfaces can form a vascular lumen filled with ECM, and that phagocytotic blood cells can clear this luminal ECM to generate a patent vascular lumen. Therefore, our experiments suggest a mechanism of blood vessel formation via basal cell surfaces in amphioxus and possibly in other invertebrates that do not have any endothelial cells. In addition, a comparison between amphioxus and mouse shows that endothelial cells physically separate the basement membranes from the vascular lumen, suggesting that endothelial cells create cardiovascular tubes with a cell polarity of epithelial tubes in vertebrates and mammals.     

Stable Isotope Metabolic Labeling with a Novel 15N-Enriched Bacteria Diet for Improved Proteomic Analyses of Mouse Models for Psychopathologies

The identification of differentially regulated proteins in animal models of psychiatric diseases is essential for a comprehensive analysis of associated psychopathological processes. Mass spectrometry is the most relevant method for analyzing differences in protein expression of tissue and body fluid proteomes. However, standardization of sample handling and sample-to-sample variability are problematic. Stable isotope metabolic labeling of a proteome represents the gold standard for quantitative mass spectrometry analysis. The simultaneous processing of a mixture of labeled and unlabeled samples allows a sensitive and accurate comparative analysis between the respective proteomes. Here, we describe a cost-effective feeding protocol based on a newly developed ¹⁵N bacteria diet based on Ralstonia eutropha protein, which was applied to a mouse model for trait anxiety. Tissue from ¹⁵N-labeled vs. ¹⁴N-unlabeled mice was examined by mass spectrometry and differences in the expression of glyoxalase-1 (GLO1) and histidine triad nucleotide binding protein 2 (Hint2) proteins were correlated with the animals'' psychopathological behaviors for methodological validation and proof of concept, respectively. Additionally, phenotyping unraveled an antidepressant-like effect of the incorporation of the stable isotope ¹⁵N into the proteome of highly anxious mice. This novel phenomenon is of considerable relevance to the metabolic labeling method and could provide an opportunity for the discovery of candidate proteins involved in depression-like behavior. The newly developed ¹⁵N bacteria diet provides researchers a novel tool to discover disease-relevant protein expression differences in mouse models using quantitative mass spectrometry.     

Maximizing power production in a stack of microbial fuel cells using multiunit optimization method

This study demonstrates real‐time maximization of power production in a stack of two continuous flow microbial fuel cells (MFCs). To maximize power output, external resistances of two air–cathode membraneless MFCs were controlled by a multiunit optimization algorithm. Multiunit optimization is a recently proposed method that uses multiple similar units to optimize process performance. The experiment demonstrated fast convergence toward optimal external resistance and algorithm stability during external perturbations (e.g., temperature variations). Rate of the algorithm convergence was much faster than in traditional maximum power point tracking algorithms (MPPT), which are based on temporal perturbations. A power output of 81–84 mW/L_A (A = anode volume) was achieved in each MFC. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

Controlling flexible manufacturing systems based on a dynamic selection of the appropriate operational criteria and scheduling policy

This study presents the development of a multi-criteria control methodology for flexible manufacturing systems (FMSs). The control methodology is based on a two-tier decision making mechanism. The first tier is designed to select a dominant decision criterion and a relevant scheduling rule set using a rule-based algorithm. In the second tier, using a look-ahead multi-pass simulation, a scheduling rule that best advances the selected criterion is determined. The decision making mechanism was integrated with the shop floor control module that comprises a real-time simulation model at the top control level and RapidCIM methodology at the low equipment control level. A factorial experiment was designed to analyze and evaluate the two-tier decision making mechanism and the effects that the main design parameters have on the system’s performance. Next, the proposed control methodology was compared to a selected group of scheduling rules/policies using DEA. The results demonstrated the superiority of the suggested control methodology as well as its capacity to cope with a fast changing environment.