Synthesis and optical properties of luminescent core-shell structured silicate and phosphate nanoparticles

Monodisperse, luminescent core-shell structured inorganic nanoparticles were synthesized by sol-gel technology. They exhibit an amorphous SiO₂ core and a crystalline luminescent shell. Zn₂SiO₄:Mn²⁺ and Ca₁₀(PO₄)₆OH:Eu³⁺ shell materials are investigated. The influence of the doping concentration on optical and structural properties was studied. The resulting nanoparticles were characterized by X-ray diffraction analysis, transmission electron microscopy, inductively coupled plasma optical emission spectrometry, and photoluminescence spectroscopy.     

Zeolitic materials with hierarchical porous structures

During the past several years, different kinds of hierarchical structured zeolitic materials have been synthesized due to their highly attractive properties, such as superior mass/heat transfer characteristics, lower restriction of the diffusion of reactants in the mesopores, and low pressure drop. Our contribution provides general information regarding types and preparation methods of hierarchical zeolitic materials and their relative advantages and disadvantages. Thereafter, recent advances in the preparation and characterization of hierarchical zeolitic structures within the crystallites by post-synthetic treatment methods, such as dealumination or desilication; and structured devices by in situ and ex situ zeolite coatings on open-cellular ceramic foams as (non-reactive as well as reactive) supports are highlighted. Specific advantages of using hierarchical zeolitic catalysts/structures in selected catalytic reactions, such as benzene to phenol (BTOP) and methanol to olefins (MTO) are presented.     

Bacterial attachment to RO membranes surface-modified by concentration-polarization-enhanced graft polymerization

Concentration polarization-enhanced radical graft polymerization, a facile surface modification technique, was examined as an approach to reduce bacterial deposition onto RO membranes and thus contribute to mitigation of biofouling. For this purpose an RO membrane ESPA-1 was surface-grafted with a zwitterionic and negatively and positively charged monomers. The low monomer concentrations and low degrees of grafting employed in modifications moderately reduced flux (by 20-40%) and did not affect salt rejection, yet produced substantial changes in surface chemistry, charge and hydrophilicity. The propensity to bacterial attachment of original and modified membranes was assessed using bacterial deposition tests carried out in a parallel plate flow setup using a fluorescent strain of Pseudomonas fluorescens. Compared to unmodified ESPA-1 the deposition (mass transfer) coefficient was significantly increased for modification with the positively charged monomer. On the other hand, a substantial reduction in bacterial deposition rates was observed for membranes modified with zwitterionic monomer and, still more, with very hydrophilic negatively charged monomers. This trend is well explained by the effects of surface charge (as measured by ζ-potential) and hydrophilicity (contact angle). It also well correlated with force distance measurements by AFM using surrogate spherical probes with a negative surface charge mimicking the bacterial surface. The positively charged surface showed a strong hysteresis with a large adhesion force, which was weaker for unmodified ESPA-1 and still weaker for zwitterionic surface, while negatively charged surface showed a long-range repulsion and negligible hysteresis. These results demonstrate the potential of using the proposed surface- modification approach for varying surface characteristics, charge and hydrophilicity, and thus minimizing bacterial deposition and potentially reducing propensity biofouling.     

Differentiation of lactococci from 2 Greek cheeses with protected designation of origin by phenotypic criteria and RAPD-PCR

Abstract: Seventy‐six lactococci isolates from 2 protected designation of origin (PDO) cheeses were studied for their acidification ability, proteolytic activity, and inhibitory activities as well as their intraspecies characterization by randomly amplified polymorphic DNA‐polymerase chain reaction (RAPD‐PCR). Fifty‐two of them were characterized as Lactococcus lactis subsp. lactis by the SDS‐PAGE of whole‐cell proteins. The test strains increased the amount of acid in milk from 6 to 24 h as well as the quantities of amino acids on incubation for 4 d. The majority of the isolates degraded preferentially α_s‐casein. The isolates from Feta differed from those of Graviera Kritis in respect of β‐casein degradation. This fragment was either not degraded or underwent a small degradation by lactococci from Feta. A stronger intensity of acidification for the isolates from Feta and a higher casein breakdown ability for those from Graviera Kritis were also recorded. Lactococci from Feta and Graviera Kritis inhibited, preferentially, the growth of Escherichia coli O157:H7, and Yersinia enterocolitica, respectively. A high heterogeneity among the isolates according to RAPD‐PCR was determined, as well as grouping of the isolates according to their source of isolation. Selected isolates from each cheese could be used as starters to make either Feta or Graviera Kritis.     

Developing monitoring indicators for urban micro contracts in South Asia

The growing emphasis in many low-income countries on community-based infrastructure means that more programmes are being implemented through micro contracts. The advantages of this approach are that it encourages:

participative negotiation of activities and speedier implementation;

the use of local resources, skills and appropriate technology; and

entrepreneurship in communities.

For client organisations, however, large numbers of very small contracts are much harder to monitor, supervise and evaluate. This paper draws upon recent research in India, Pakistan and Sri Lanka to develop a ‘benchmarking framework' to study the time and cost performance of 162 small-scale contracts for urban infrastructure. The study found that costs were normally very close to target, but project duration generally far exceeded the target. There is only a weak association between the cost and time growth.     

Effect of surface modifiers on the electrode reactions and conformation of cytochrome c3 adsorbed on a silver electrode

Higher rates of left-handedness and atypical lateralization in schizophrenics paired with findings of morphological abnormalities in cerebral asymmetry suggest that the normal patterns of hemisphere specialization for processing verbal and spatial information may be anomalous in schizophrenics. The small number of studies that have addressed this question have produced inconsistent findings and varied with subtype diagnosis, gender, type of task employed, task difficulty, and control of handedness. Conflicting research findings also may be due to confounding from the heterogeneity of the schizophrenic construct and variability in clinical symptoms across patients. The present study was designed to control for factors that may have confounded earlier studies. Because the study used perceptual measures, the relationship between symptoms of perceptual aberration and hemisphere advantages was examined using Chapman et al.'s (1978) Perceptual Aberration Scale (PAS). Fifteen male schizophrenic patients and 14 male controls were administered tachistoscopic letter and facial recognition go/no-go reaction time tasks. Left hemisphere advantages were found for both controls and schizophrenics on the letter task. Right hemisphere advantages were found for controls on the facial task but not schizophrenics. Instead, a strong negative correlation was found between schizophrenics' PAS scores and hemisphere advantages (r = -0.685, p < 0.007). Further analysis identified a subgroup of schizophrenics with perceptual aberration who exhibited reversed left hemisphere advantages that increased as the PAS scores increased. Additional research is needed to determine whether this subgroup of schizophrenics constitutes a meaningful subtype with a distinct disease process that disrupts the development of normal cerebral lateralization. The findings provide further evidence for the importance of examining relationships between schizophrenics' performance on cognitive measures and their symptom patterns.     

The refurbishment and development of a leading HV laboratory - bridging the academic and industrial divide

A refurbished laboratory has been set up in the University of Manchester to study high voltage (HV) engineering. This has been achieved with the support of the National Grid Transco (NGT). This support has included new equipment, a new academic appointment, and refurbished teaching facilities. Combine this with the existing expertise in the electrical engineering department on power system analysis and the excellent Materials and other physical sciences in the university, and it can be understood why the team here is now in a great position to continue to deliver world-class research.     

Potentially reactive cyclic carbamate metabolite of the antiepileptic drug felbamate produced by human liver tissue in vitro

To gain insights into the different forms of modified amyloid beta peptides (A beta) in the Alzheimer disease (AD) and Down syndrome (DS) brain, we used two-site ELISAs with antibodies specific for isomerized (i.e. A beta with L-isoaspartate at positions 1 and 7) and pyroglutamate-modified (i.e. A beta beginning with pyroglutamate at position 3) forms of A beta to quantitate the levels of these different A beta peptides in formic acid extracts of AD and DS frontal cortex. Despite variations in the proportions of distinct forms of A beta in AD and DS frontal cortex, the major species of A beta in these samples were A betaN3(pyroGlu)-42 as well as A beta x-42 (where x is a residue at position 2 or less in A beta), whereas isomerized A beta was a minor species. Further, the levels of isomerized and pyroglutamate-modified forms of A beta terminating at amino acid 42 were higher than those ending at amino acid 40. The abundance of the distinct forms of A beta reported here in formic acid extracts of AD and DS frontal cortex suggests that these A beta species could play important roles in the deposition of A beta in AD and DS brains.     

Increased 24-hour endothelin-1 urinary excretion in patients with chronic obstructive pulmonary disease

Abnormalities in endothelin-1 (ET-1) pulmonary metabolism have been reported in patients with pulmonary hypertension, asthma and chronic obstructive pulmonary disease (COPD). In this study we have evaluated the 24-hour urinary excretion of ET-1 in COPD patients both during acute exacerbation and stable phase of the disease. ET-1 plasma and urinary levels were measured in 13 COPD patients on admission to the hospital for an acute exacerbation and at the recovery period. Ten healthy volunteers were also studied. Determination of plasma and 24-Hour urinary ET-1 levels were carried out with a radioimmunoassay test. Plasma ET-1 levels in COPD patients were similar during exacerbation and recovery and were not significantly different from those in the healthy subjects. 24-hour urinary excretion of ET-1 was increased in COPD patients during acute exacerbation; it decreased during recovery, but remained elevated when compared to normal subjects. A negative correlation was found between arterial oxygen pressure and ET-1 excretion; no correlation was found between plasma and urinary ET-1 values. In conclusion, COPD patients excrete higher amounts of ET-1 compared to healthy subjects. Urinary ET-1 values are further increased during acute exacerbation of the disease.