Expression and characterization of the recombinant gene encoding chitinase from Aeromonas caviae

The gene encoding a chitinase from Aeromonas caviae was cloned by PCR techniques. Its recombinant gene expression was performed using pET20b(+) in Escherichia coli BL21 (DE3). The recombinant chitinase with the extra 33 and 13 amino acids in its N- and C-termini, respectively, was purified to near homogeneity using His-Tag affinity chromatography. The recombinant chitinase was found to be present in both the culture medium and the cytoplasm. A single protein band on the native polyacrylamide gel was confirmed by both the activity staining and protein staining. The optimum pH and temperature of the recombinant chitinase were determined to be 6.25-6.5 and 42.5 degrees C, respectively. It was stable within the pH range of 5-7. Significant activity stimulation by Cu2+ and inhibition by Fe3+ and Hg2+ were observed. Detergents such as SDS and Triton X-100 strongly inhibited the enzyme activity. Substrates such as 4-methylumbelliferyl-N,N'-diacetylchitobioside and 4-methylumbelliferyl-N,N',N"-triacetylchitotriose were hydrolyzed by the recombinant chitinase; however, 4-methylumbelliferyl-N-acetylglucosaminide was not cleaved during the activity assay periods. When chitin power was suspended in buffer with the chitinase (pH 6.5 and 42.5 degrees C), N-acetylchitooligosaccharides [(GlcNAc)n, n = 1-4] were detected at 24 h.     

Occupational injuries among workers with disabilities: the National Health Interview Survey, 1985-1994

CONTEXT: As the baby boom generation ages, more people will be working with disabilities, but we have little information regarding how disabilities affect risk for occupational injury. OBJECTIVE: To test the hypothesis that work-limiting disabilities in general and hearing and visual impairments in particular are risk factors for occupational injuries. DESIGN: Retrospective cohort study. SETTING: The National Health Interview Survey (NHIS), 1985 to 1994. PARTICIPANTS: The 459827 participants in the NHIS from 1985 to 1994 who listed "working" as their primary activity, who were not farmers, and who were between 18 and 65 years of age. MAIN OUTCOME MEASURE: Occupational injuries in the year preceding the interview causing a residual impairment at the time of interview. RESULTS: After adjusting for occupation, self-employment, and age, occupational injury was associated with preceding work disability (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.19-1.56); blindness (OR, 3.21; 95% CI, 1.32-7.85); deafness (OR, 2.19; 95% CI, 1.17-4.12); hearing impairment (OR,1.55; 95% CI, 1.29-1.87); upper extremity impairment (OR, 1.46; 95% CI, 1.05-2.05); and arthritis (OR, 1.34; 95% CI, 1.07-1.68). Visual impairment was not associated with a significantly increased risk (OR, 1.37; 95% CI, 0.87-2.17). CONCLUSIONS: Workers with disabilities, especially sensory impairments, appear to have an elevated risk for occupational injury. Further research in the design and evaluation of improved workplace accommodations for workers with these disabilities is needed.     

Traumatic brain injury in children and adolescents: psychiatric disorders at two years

OBJECTIVE: To extend findings regarding predictive factors of psychiatric outcome from the first to the second year after traumatic brain injury (TBI) in children and adolescents. METHOD: Subjects were children aged 6 to 14 years at the time they were hospitalized after TBI. The study used a prospective follow-up design. Assessments of preinjury psychiatric, behavioral, adaptive functioning, family functioning and family psychiatric history status were conducted. Severity of injury was assessed by standard clinical scales and neuroimaging was analyzed. The outcome measure was the presence of a psychiatric disorder, not present before the injury ("novel"), during the second year after TBI. RESULTS: Fifty subjects enrolled, and the analyses focused on 42 subjects followed at 24 months. Severity of injury, preinjury family function, and preinjury lifetime psychiatric history predicted the development of a "novel" psychiatric disorder present in the second year. CONCLUSION: These data suggest that there are children, identifiable through clinical assessment, at increased risk for "novel" psychiatric disorders in the second year after TBI.     

From authorship to contributorship. Promoting integrity in research publication

Shared authorship in nursing research presents practical and ethical dilemmas and does not effectively capture individual research participation and accountability. This study, which defined author contributions and practices in multiauthored nursing research, contributed to a better understanding of contemporary author participation and the inherent challenges faced by nurse scholars in determining authorship credit. A method of "contributorship" is proposed which would delineate individual contributions to the research project while maintaining professional integrity, scientific accountability, and scholarly recognition.     

Laboratory and field evaluations of oviposition responses of Aedes albopictus and Aedes triseriatus (Diptera: Culicidae) to oak leaf infusions

Organic infusions created by fermenting white oak (Quercus alba L.) leaves in water were evaluated as sources of attractant odorants and contact oviposition stimulants for gravid Aedes albopictus (Skuse) and Aedes triseriatus (Say). Infusions were bioassayed in the laboratory by giving single females a choice of ovipositing in 1 container with infusion and 7 containers with water. Ae. albopictus laid significantly more eggs in containers with infusion, regardless of concentration (dilutions ranging from 10 to 100%) or age (fermentation periods of 7, 28, 60 d), than in containers holding water. The largest proportion of eggs (76.8%) was deposited in response to a 60% concentration of 7-d-old infusion. In contrast, Ae. triseriatus exhibited variable oviposition responses but generally deposited the largest number of eggs in only a few concentrations of older age infusions. In binary "sticky screen" bioassays, there was no difference between the numbers of females attracted to infusion or water, indicating that oviposition responses to infusion were mediated by contact chemostimulants rather than by attraction to odorants. Oviposition responses to infusions by field populations of Ae. albopictus and Ae. triseriatus in Raleigh, NC, were evaluated with pairs of oviposition traps, one containing infusion and the other containing water. Generally, Ae. albopictus laid significantly more eggs in ovitraps containing infusion regardless of its age (7, 28, and 60 d old) or the mass of leaves fermented (126 g = 1x or 504 g = 4x) than in water. In contrast, Ae. triseriatus deposited an equivalent number of eggs in traps containing water or 1x, 80% infusion regardless of its age; however, the oviposition response to ovitraps containing 4x, 7-d-old, 50% infusion was significant. Placement of an automobile tire behind an ovitrap did not increase the number of Ae. albopictus eggs laid in ovitraps containing 4x, 7-d-old, 50% infusion or water relative to ovitraps without a tire. Our research indicates that baiting ovitraps with oak leaf infusion would increase the sensitivity of surveillance efforts for Ae. albopictus and Ae. triseriatus.     

Discovery of type II (covalent) inactivation of S-adenosyl-L-homocysteine hydrolase involving its "hydrolytic activity": synthesis and evaluation of dihalohomovinyl nucleoside analogues derived from adenosine

Treatment of the 5'-carboxaldehyde derived by Moffatt oxidation of 6-N-benzoyl-2',3'-O-isopropylideneadenosine (1) with the "(bromofluoromethylene)triphenylphosphorane" reagent and deprotection gave 9-(6-bromo-5, 6-dideoxy-6-fluoro-beta-d-ribo-hex-5-enofuranosyl)adenine (4). Parallel treatment with a "dibromomethylene Wittig reagent" and deprotection gave 9-(6,6-dibromo-5, 6-dideoxy-beta-d-ribo-hex-5-enofuranosyl)adenine (7), which also was prepared by successive bromination and dehydrobromination of the 6'-bromohomovinyl nucleoside 8. Bromination-dehydrobromination of the 5'-bromohomovinyl analogue 11 and deprotection gave (E)-9-(5, 6-dibromo-5,6-dideoxy-beta-d-ribo-hex-5-enofuranosyl)adenine (15). Compounds 4, 7, and 15 were designed as putative substrates of the "hydrolytic activity" of S-adenosyl-l-homocysteine (AdoHcy) hydrolase. Enzyme-mediated addition of water across the 5,6-double bond could generate electrophilic acyl halide or alpha-halo ketone species that could undergo nucleophilic attack by proximal groups on the enzyme. Such type II (covalent) mechanism-based inactivation is supported by protein labeling with 8-[3H]-4 and concomitant release of bromide and fluoride ions. Incubation of AdoHcy hydrolase with 7 or 15 resulted in irreversible inactivation and release of bromide ion. In contrast with type I mechanism-based inactivation, reduction of enzyme-bound NAD+ to NADH was not observed. Compounds 4, 7, and 15 were not inhibitory to a variety of viruses in cell culture, and weak cytotoxicity was observed only for CEM cells.     

A calculation of the relative biological effectiveness of 125I and 103Pd brachytherapy sources using the concept of proximity function

The clinical application of encapsulated radioactive sources in brachytherapy plays an important role in the treatment of malignancy. 125I and 103Pd sources have been widely used in the permanent implant of prostate cancer. An important consideration for the choice of brachytherapy sources is their relative biological effectiveness (RBE). Previous calculations of this quantity have used the dose-averaged lineal energy, yD, as a measure of biological effectiveness. In this approach, however, the selection of a relevant site size remains an open question. Here we avoid this problem by using the generalized theory of dual radiation action to calculate the initial slope, alpha, of the dose-effect curves using the proximity function, t(x), and the biological response function, gamma(x). At low doses and/or low dose rates (e.g., prostate implants) the parameter alpha determines the RBE. Proximity function, t(x), is the probability distribution function of distances between pairs of sublesions; and the biological function, gamma(x), is the probability that two sublesions at a distance x apart results in a lesion. Functions t(x) have been calculated for each source using the Monte Carlo transport codes PHOEL and PROTON5. The function gamma(x) has been taken from a published analysis. The RBE values thus obtained are: 1.5 for 125I and 1.6 for 103Pd. The question of whether an "effective" site size exists where yD approximates best the variation of alpha with radiation quality is also addressed.     

An analysis of satellite-derived chlorophyll and algal bloom indices on Lake Winnipeg

Lake Winnipeg has experienced dramatic increases in nutrient loading and phytoplankton biomass over the last few decades, accompanied by a marked shift in community composition towards the dominance of cyanobacteria. Comprehensive lake-wide observations of algal blooms are critical to assessing the lake's health status, its response to nutrient management practices, and an improved understanding of the processes driving blooms. We present an analysis of the spatial and temporal variability of algal blooms on Lake Winnipeg using satellite-derived chlorophyll and indices for algal bloom intensity, spatial extent, severity, and duration over the period of ESA's MERIS mission (2002–2011). Imagery documented extensive blooms covering as much as 93% of the lake surface. Bloom conditions were analysed in the context of in-lake and watershed processes to gain further insight on the drivers of bloom events. Day to day bloom variability was driven primarily by intermittent wind mixing events, with quiescent periods leading to the formation of dense surface blooms. Seasonal bloom distribution was consistent with light limitation in the south basin and lake circulation transporting bloom material towards the north-east shore. Inter-annual variability in average bloom severity was related to both total phosphorus (TP) loadings and summer lake surface temperatures. Results provide a valuable historical time series of bloom conditions to which ongoing observations from Sentinel-3's OLCI sensor can be added for longer term monitoring and change detection.     

Improvement of Plasma Gun Performance Using Comprehensive Fluid Element Modeling II

Use of a comprehensive validated computer model of a thermal spray process enables an ability to improve, optimize, and fine-tune the performance of that thermal spray process. A validated model of the Sulzer Metco TriplexPro™ 200 plasma gun has been used to improve the performance of the actual gun in terms of enhancing gas flow dynamics, thermal management, and overall performance in terms of a robust design. Internal changes to the gun geometry using the model have extended the life of the hardware. In addition the model has permitted the investigation of the fundamental operation of the gun, specific to the behavior and path of the arcs, as well as the ability to operate the plasma gun, under simulation, in operating regimes that currently cannot be supported by the physical hardware. The model has been run at gas pressures above 1.4 Mpa and/or voltages above 300 V that currently cannot be obtained with the physical hardware due to equipment limitations to evaluate the potential to extend the operating window of the Sulzer Metco TriplexPro™ 200 gun beyond current levels in terms of particle velocity and temperature. The end result is an improved process tool for applying thermal spray coatings ranging from ceramics applied at high particle temperature and low particle velocities to carbides and alloys applied at lower temperatures and higher velocities. This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2007.     

Is gratitude a moral affect?

Gratitude is conceptualized as a moral affect that is analogous to other moral emotions such as empathy and guilt. Gratitude has 3 functions that can be conceptualized as morally relevant: (a) a moral barometer function (i.e., it is a response to the perception that one has been the beneficiary of another person's moral actions); (b) a moral motive function (i.e., it motivates the grateful person to behave prosocially toward the benefactor and other people); and (c) a moral reinforcer function (i.e., when expressed, it encourages benefactors to behave morally in the future). The personality and social factors that are associated with gratitude are also consistent with a conceptualization of gratitude as an affect that is relevant to people's cognitions and behaviors in the moral domain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)