Water treatment and monitor disinfection

Water treatment system and dialysis monitors are susceptible to microbial contaminations and periodical disinfection procedures are mandatory to obtain results requested from international standards and guidelines. Several chemical germicides or some physical treatments are on the market validated by device manufacturer according to medical device directives. With time, interfering substances from dialysis device or water are able to modify disinfection efficiency. Simulating-use testing is not a common procedure to validate disinfectants and recent data document as biofilm represents the most important cause of disinfection inefficacy. Some international standards include tests in the presence of various interfering substances but their use is not widespread. When using a disinfectant, residue toxicity, material compatibility and potential risks for the staff also have to be considered. A quality assurance program has to be implemented to obtain adequate performances and to improve results on patients.     

Antioxidant properties of lucerne extracts

Aqueous extracts of fresh and dehydrated lucerne were found to exhibit heat-stable antioxidant activity toward the autoxidation of linoleic acid, the lipoxidase-catalysed oxidation of linoleic acid and the lipoxidase-induced carotene oxidation. EDTA increased the antioxidant activity of lucerne extract in all three systems. Alone, EDTA inhibited linoleate autoxidation, but not lipoxidase-catalysed linoleate oxidation, and was only partly inhibitory toward lipoxidase-induced carotene oxidation. The presence of ferulic acid in the acid hydrolysate of lucerne extract could be demonstrated by both paper and gas chromatography. This acid, and the related coumaric and sinapic acids, were shown to inhibit lipoxidase activity. It is suggested that a ferulic acid derivative may play a rôle in the antioxidant effects observed with aqueous lucerne extracts.     

Intraindividual variability in HIV infection: Evidence for greater neurocognitive dispersion in older HIV seropositive adults.

Objective: Both the prevalence and incidence of HIV infection among older adults are on the rise. Older adults are at increased risk of HIV-associated neurocognitive disorders, which have historically been characterized as an inconsistent or “spotty” pattern of deficits. Dispersion is a form of intraindividual variability (IIV) that is defined as within-person variability in performance across domains and has been associated with poorer neurocognitive functioning and incipient decline among healthy older adults. To our knowledge, no studies have yet examined dispersion in an aging HIV-infected sample. Method: For the current study we examined the hypothesis that age and HIV infection have synergistic effects on dispersion across a battery of clinical and experimental cognitive tasks. Our well-characterized sample comprised 126 HIV-seropositive individuals (HIV+) and 40 HIV-seronegative comparison individuals (HIV?), all of whom were administered a comprehensive neuropsychological battery. Results: Consistent with our hypothesis, an age by HIV serostatus interaction was observed, with the older HIV+ group demonstrating a higher level of dispersion relative to older HIV? and younger HIV+ individuals, even when potentially confounding demographic and medical factors were controlled. Conclusion: Our results demonstrate that older HIV+ adults produce greater dispersion, or intraindividual variability in performance across a range of tests, which may be reflective of cognitive dyscontrol to which this population is vulnerable, perhaps driven by the combined effects of aging and HIV infection on prefrontostriatal systems. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Longitudinal examination of American National Adult Reading Test (AMNART) performance in dementia of the Alzheimer type (DAT): validation and correction based on degree of cognitive decline

The American National Adult Reading Test (AMNART) was constructed to provide a valid and stable estimate of premorbid verbal IQ (VIQ) in dementing individuals. However, recent studies have brought into question its validity in patients with dementia of the Alzheimer type (DAT). The present study was designed to longitudinally assess the validity of the AMNART in 40 DAT patients and 40 demographically matched normal control (NC) subjects. The results showed that VIQ estimates for patients with DAT were significantly lower than those of NC subjects and declined significantly over time with increasing dementia severity as measured by the Mini-Mental State Examination (MMSE) and the Dementia Rating Scale (DRS). An MMSE-based correction factor was derived for the DAT group which allows for the effective estimation of premorbid VIQ in these patients.     

Eyeblink Classical Conditioning to Auditory and Olfactory Stimuli: Performance Among Older Adults With and Without the Apolipoprotein E ε4 Allele.

Patients with Alzheimer's disease (AD) demonstrate slowed acquisition of the conditioned response (CR) in eyeblink classical conditioning paradigms (EBCC), although it is unknown how early in the course of the disease CR acquisition is affected. This study investigated whether changes in the rate of CR acquisition were apparent in nondemented older adults at greater genetic risk for developing AD (i.e., carriers of the apolipoprotein E [APOE] ε4 allele). Both ε4+ and ε4- participants demonstrated CR acquisition to auditory and olfactory CSs; however, rate of acquisition to the olfactory CS was significantly slower in ε4+ persons. Both groups acquired the CR to an auditory CS at the same rate. Results support olfactory compromise in the earliest stages of the AD disease process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laser assisted chemical vapor deposition synthesis of carbon nanotubes and their characterization

The deposition of carbon nanotubes using the laser assisted chemical vapor deposition process was studied to determine the effects of processing conditions on the quantity and quality of the tubes. A structured experimental design was utilized to test the effects of laser power, and concentration of the two precursors, acetylene and iron pentacarbonyl. Processing conditions were optimized with the assistance of heat and mass transport modeling. The synthesis of lines of carbon nanotubes as well as deposits formed under the influence of an electric field were also investigated.     

Vitamin A and carotene in animal nutrition

Vitamin A, an unsaturated 20 carbon cyclic alcohol, subserves a number of important physiological functions. However, the biochemical basis of these roles is not well understood. The main sources of retinol are liver, egg yolk and milk fat. Several carotenoids show vitamin A activity. The conversion of beta-carotene to retinol is affected by copper-containing dioxygenase and zinc-containing retinene reductase. The efficiency of conversion varies in different species. The latter is defined in units as the daily dose required to produce a weight gain of 3 g/week in young rats between the 4th and 8th week. Retinol is unstable on exposure to light or heat, particularly in the presence of heavy metal ions and water. Much recent work has focused on the absorption, metabolism and excretion of vitamin A. It is now recognized that plasma vitamin A levels do not reflect the nutritional status except in severe hypo- and hypervitaminosis A. Also, many dietary factors may influence vitamin A metabolism. These basic and applied aspects of vitamin A are reviewed.     

Vancomycin-resistant enterococci (VRE) in meat and environmental samples

We investigated the spread of vancomycin-resistant enterococci (VRE) in strains from meat and environmental samples and the location of glycopeptide-resistance determinants in VanA isolates. VRE and VSE (vancomycin-sensitive enterococci) resistance patterns to six antimicrobials were also evaluated. A total of 59 meat isolates (35%) and 119 environmental isolates (26.5%) were glycopeptide resistant enterococci. In particular, 10.7% meat isolates belonged to the VanA, 8.3% to VanB and 16% to VanC phenotypes. Environmental samples presented 0.7% VanA, 14.5% VanB, and 11.4% VanC strains. Evident differences were not observed among the resistance patterns of VRE and VSE isolates. Neither an important difference was observed comparing the resistance patterns in enterococci from meat and environment. In particular a low incidence of beta-lactamic resistant strains was found, whereas high rates of resistance were observed for streptomycin (85.7% and 92.8%), kanamycin (79.7% and 96%) and gentamycin (85.1% and 91.7%). An intermediate rate of resistant bacteria emerged for erythromycin (35.1% and 10.5%). All VanA isolates independent of origin had more plasmids with different molecular weights. PCR amplification of the 732 bp fragment in plasmids from the VanA strains confirmed affiliation to the vanA gene cluster and the extrachromosomal location of the glycopeptide-resistance determinants. Our study suggests that food and environment play a potential role as reservoirs of resistance determinants, prompting the need to undertake epidemiological and molecular studies to evaluate the mobility of these genes.     

Diurnal fluctuations in polybrominated diphenyl ether concentrations during and after a severe dust storm episode in Kuwait City, Kuwait

Concentrations of polybrominated diphenyl ethers (PBDEs) were quantified in four-hour integrated air samples obtained serially over a five day period in May 2007 in Kuwait City during and after a severe dust storm. The ∑PBDE concentrations ranged from 51 to 1307 pg m(-3) for the first two days of sampling and 20 to 148 pg m(-3) for the rest of the sampling period. The first two days of sampling occurred during a severe dust storm episode when the total suspended particulates (TSP) in air exceeded 1000 μg/m(3) with concentrations peaking during the day and decreasing at night. During this dust episode, the peak nighttime PBDE concentration was 30 times higher than the minimum daytime concentration. Although ∑PBDE concentrations peaked at night during the first two sampling days, the fluctuations in the BDE 47:99 ratio tracked changes in ambient temperature remarkably well, following a clear diurnal pattern. The fraction of congeners in the gas phase varied inversely with solar flux and was lower on days with a high number of hours of sunshine, suggesting that photolytic degradation of gas-phase PBDEs was occurring.     

A performance model of a design for a minimally replicated distributed database for database-driven telecommunications services

In intelligent networking telecommunication services such as free-phone and various personal communications services, the dialed number corresponds to the identity of the called party rather than to the called party's physical location. The dialed number must therefore be converted to a routable telephone number during call setup. This accomplished by querying a database. If the query is successful, its result is a routable number which is passed to the switch at which the call originates so that the call may be completed. A database maintained solely at a single node may not be sufficient to support the large capacity, reliability, and rapid processing requirements of this service. However, these requirements may be met by replicating and distributing the database instead.Replication and distribution induce problems of consistency, concurrency, and load balancing. We describe and present a performance model of a scheme for replicating customer profiles efficiently. To spread the query transaction load, the database and its replicates could be distributed over a set of geographically distinct nodes. The database would be partitioned into as many disjoint fragments as there are nodes. Each fragment would be stored at two of the nodes, subject to the constraint that no pair of subsets would be stored at more than one node. This constraint ensures that the load which would have been carried by a failed node is spread to two other nodes instead of one, thus reducing the risk of overload in case of failure. We also use a performance analysis to arrive at heuristics for routing transactions within the database which attempt to minimize the query and update response times. For a particular implementation, the analysis suggests that READ or query transactions should be routed to the least loaded node of those holding the fragment of interest. By contrast, when strict locking of all copies is required while performing an update, WRITE or update transactions which are initiated at one node and repeated at the other should be routed to the more heavily loaded of the nodes to minimise overall response time. Recommended by: Amit ShethA shorter version of this paper was presented at the 8th ITC Specialist Seminar on Universal Personal Telecommunications held at Santa Margherita Ligure, Italy, in October 1992.