3,722 research outputs found
An approach to light-frame disaster relief housing
An Approach to Light-Frame Disaster Relief Housing investigated the use of bamboo structures to provide safe, affordable and easily constructible housing in developing countries that are prone to natural disasters. The team chose to use the Cagayan Valley Region in Northern Philippines that has a demonstrated need for relief housing due to its susceptibility to high seismic activity, monsoons, and floods. The proposed solution includes a complete structural and geotechnical foundation design of a house that can resist the demand loads determined for the region. The structural system is designed using bamboo and includes a lateral force resisting system, and gravity force resisting system, and roof and floor diaphragms. The structural system ties into the foundation, which was designed to withstand flood loads and provide a proper load path from the structural system to the ground
Effects of octane on the fatty acid composition and transition temperature of Pseudomonas oleovorans membrane lipids during growth in two-liquid-phase continuous cultures
Growth of Pseudomonas oleovorans GPol in continuous culture containing a bulk n-octane phase resulted in changes of the fatty acid composition of the membrane lipids. Compared to citrate-grown cells, the ratio of C18 to C16 fatty acids and the ratio of unsaturated to saturated fatty acids increased as a result of growth on octane. Trans-unsaturated fatty acids, which are rarely found in bacteria, were formed during continuous growth of P. oleovorans on octane. Moreover, the mean acyl chain length and unsaturated fatty acids also increased as the growth rates increased both in octane-grown and citrate-grown cells. Differential scanning calorimetry measurements of extracted lipids showed the transition temperature of membrane lipids from octane-grown cells increased from about 24°C to 32°C as the growth rate increased, whereas cells grown on citrate showed a constant transition temperature of about 6°C at all growth rates tested, indicating a decrease of membrane lipid fluidity in octane-grown cells. Because alkanes are known to increase bilayer fluidity by intercalating between lipid fatty acyl chains, the increased transition temperature of the lipids of cells grown on octane may be a physiological response of P. oleovorans to compensate for the direct effects of octane on its cellular membranes.
The Use of Rank Transformation and Multiple Regression Analysis in Estimating Residential Property Values With A Small Sample
Conventional multiple regression analysis which has been used in estimating residential property values typically relies upon cardinal data. This paper argues that appraisal theory requires the appraiser to rank the comparables from best to worst and use a regression technique which can be applied to ordinal data. The rank regression procedure illustrated here was successfully used on small sample sizes, and did not violate the critical assumptions underlying conventional multiple regression. The results indicate that the rank regression technique illustrated here is more theoretically correct than conventional multiple regression and produces a better model with more accurate price estimates.
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A conserved morphogenetic mechanism for epidermal ensheathment of nociceptive sensory neurites.
Interactions between epithelial cells and neurons influence a range of sensory modalities including taste, touch, and smell. Vertebrate and invertebrate epidermal cells ensheath peripheral arbors of somatosensory neurons, including nociceptors, yet the developmental origins and functional roles of this ensheathment are largely unknown. Here, we describe an evolutionarily conserved morphogenetic mechanism for epidermal ensheathment of somatosensory neurites. We found that somatosensory neurons in Drosophila and zebrafish induce formation of epidermal sheaths, which wrap neurites of different types of neurons to different extents. Neurites induce formation of plasma membrane phosphatidylinositol 4,5-bisphosphate microdomains at nascent sheaths, followed by a filamentous actin network, and recruitment of junctional proteins that likely form autotypic junctions to seal sheaths. Finally, blocking epidermal sheath formation destabilized dendrite branches and reduced nociceptive sensitivity in Drosophila. Epidermal somatosensory neurite ensheathment is thus a deeply conserved cellular process that contributes to the morphogenesis and function of nociceptive sensory neurons
Sleep Disturbances in Fibromyalgia Syndrome: Relationship to Pain and Depression
Objective
This study is an examination of sleep, pain, depression, and physical functioning at baseline and 1-year followup among patients with fibromyalgia syndrome (FMS). Although it is clear that these symptoms are prevalent among FMS patients and that they are related, the direction of the relationship is unclear. We sought to identify and report sleep problems in this population and to examine their relationship to pain, depression, and physical functioning.
Methods
Patients diagnosed with fibromyalgia were recruited from a Southern California health maintenance organization and evaluated according to American College of Rheumatology criteria in the research laboratory. Six hundred patients completed the baseline assessment and 492 completed the 1-year assessment. Measures included the Center for Epidemiologic Studies Depression Scale, the McGill Pain Questionnaire, the Pittsburgh Sleep Quality Index, and the Fibromyalgia Impact Questionnaire.
Results
The majority of the sample (96% at baseline and 94.7% at 1 year) scored within the range of problem sleepers. Path analyses examined the impact of baseline values on 1-year values for each of the 4 variables. No variable of interest predicted sleep, sleep predicted pain (β = 0.13), pain predicted physical functioning (β = −0.13), and physical functioning predicted depression (β = −0.10).
Conclusion
These findings highlight the high prevalence of sleep problems in this population and suggest that they play a critical role in exacerbating FMS symptoms. Furthermore, they support limited existing findings that sleep predicts subsequent pain in this population, but also extend the literature, suggesting that sleep may be related to depression through pain and physical functioning
Structural basis for the inhibition of RecBCD by Gam and its synergistic antibacterial effect with quinolones
Our previous paper (Wilkinson et al, 2016) used high-resolution cryo-electron microscopy to solve the structure of the Escherichia coli RecBCD complex, which acts in both the repair of double-stranded DNA breaks and the degradation of bacteriophage DNA. To counteract the latter activity, bacteriophage λ encodes a small protein inhibitor called Gam that binds to RecBCD and inactivates the complex. Here, we show that Gam inhibits RecBCD by competing at the DNA-binding site. The interaction surface is extensive and involves molecular mimicry of the DNA substrate. We also show that expression of Gam in E. coli or Klebsiella pneumoniae increases sensitivity to fluoroquinolones; antibacterials that kill cells by inhibiting topoisomerases and inducing double-stranded DNA breaks. Furthermore, fluoroquinolone-resistance in K. pneumoniae clinical isolates is reversed by expression of Gam. Together, our data explain the synthetic lethality observed between topoisomerase-induced DNA breaks and the RecBCD gene products, suggesting a new co-antibacterial strategy
A Procedure for Uncovering Acceptable and Nonacceptable Mortgage Applications through Discriminant Analysis Using Ranked Data
The procedure developed in this paper uses a less biased statistical technique than conventional discriminant analysis and parallels the ranking procedure used by loan officers. A variety of univariate and multivariate statistical procedures as well as comprehensive validation methods are used to develop a "best" model. The resulting model provides more accurate classification than other studies have shown, without violating federal law regarding discrimination.
Self-report versus care provider registration of healthcare utilization: impact on cost and cost-utility
OBJECTIVES: This study aims to compare the impact of two different sources of resource use, self-report versus care provider registrations, on cost and cost utility. METHODS: Data were gathered for a cost-effectiveness study performed alongside a 2-year randomized controlled trial evaluating the effect of an INTERdisciplinary COMmunity-based management program (INTERCOM) for patients with chronic obstructive pulmonary disease (COPD). The program was offered by physiotherapists, dieticians and respiratory nurses. During the 2-year period, patients reported all resource use in a cost booklet. In addition, data on hospital admissions and outpatient visits, visits to the physiotherapist, dietician or respiratory nurse, diet nutrition, and outpatient medication were obtained from administrative records. The cost per quality-adjusted life-year (QALY) was calculated in two ways, using data from the cost booklet or registrations. RESULTS: In total, 175 patients were included in the study. Agreement between self-report and registrations was almost perfect for hospitalizations (rho = 0.93) and physiotherapist visits (rho = 0.86), but above 0.55, moderate, for all other types of care. The total cost difference between the registrations and the cost booklet was 464 euros with the highest difference for hospitalizations 386 euro. Based on the cost booklet the cost difference between the treatment group and usual care was 2,444 euros (95 percent confidence interval [CI], -819 to 5,950), which resulted in a cost-utility of 29,100 euro/QALY. For the registrations, the results were 2,498 euros (95 percent CI, -88 to 6,084) and 29,390 euro/QALY, respectively. CONCLUSIONS: This study showed that the use of self-reported data or data from registrations effected within-group costs, but not between-group costs or the cost utility
A model of solid-solution interactions in acid organic soils, based on the complexation properties of humic substances
CHAOS (Complexation by Humic Acids in Organic Soils) is a quantitative chemical model of organic soils that incorporates complexation by the functional groups of humic substances and non-specific ion-exchange reactions. The two types of interaction are linked by the net humic charge, Z, which depends on the extents of proton and metal complexation, and which in turn determines ionic concentrations in the diffuse part of the electrical double layer, by a Donnan equilibrium. CHAOS was found to account satisfactorily for the results of acid-base titration experiments (pH range 3–5) with soil samples, giving reasonable simultaneous predictions of solution pH and concentration of A13+. Predictive calculations with CHAOS suggest that organic soils acidified by acid rain would respond on a time-scale of years-to-decades to reductions in rain acidity. An associated effect might be an increase in the concentration of dissolved organic matter in the soil solution
Knockout studies reveal an important role of <i>plasmodium</i> lipoic acid protein ligase a1 for asexual blood stage parasite survival
Lipoic acid (LA) is a dithiol-containing cofactor that is essential for the function of a-keto acid dehydrogenase complexes. LA acts as a reversible acyl group acceptor and 'swinging arm' during acyl-coenzyme A formation. The cofactor is post-translationally attached to the acyl-transferase subunits of the multienzyme complexes through the action of octanoyl (lipoyl): <i>N</i>-octanoyl (lipoyl) transferase (LipB) or lipoic acid protein ligases (LplA). Remarkably, apicomplexan parasites possess LA biosynthesis as well as scavenging pathways and the two pathways are distributed between mitochondrion and a vestigial organelle, the apicoplast. The apicoplast-specific LipB is dispensable for parasite growth due to functional redundancy of the parasite's lipoic acid/octanoic acid ligases/transferases. In this study, we show that <i>LplA1</i> plays a pivotal role during the development of the erythrocytic stages of the malaria parasite. Gene disruptions in the human malaria parasite <i>P.falciparum</i> consistently were unsuccessful while in the rodent malaria model parasite <i>P. berghei</i> the <i>LplA1</i> gene locus was targeted by knock-in and knockout constructs. However, the <i>LplA1</i> <sup>(-)</sup> mutant could not be cloned suggesting a critical role of LplA1 for asexual parasite growth <i>in vitro</i> and <i>in vivo</i>. These experimental genetics data suggest that lipoylation during expansion in red blood cells largely occurs through salvage from the host erythrocytes and subsequent ligation of LA to the target proteins of the malaria parasite
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