9,063 research outputs found
Bioremediation: Factors Influencing Metal Ion Toxicity in a Toluene Selected Bacterial Population
This research was a general phenomenalistic overview of the effects of metals on the respiration rates of a toluene selected microbe culture. The metals studied were copper, zinc, cobalt, manganese and iron. Relative inhibition, Cu\u3eFe\u3eZn=Co\u3eMn, corresponded to hydrogen phosphate binding strengths. Inhibition was found to be pH dependent; it increased with increasing pH and was shown to correlate to an increased adsorption of metal onto the cell. Zn, Cu, and Co toxicities were shown to decrease with increasing magnesium concentrations. This decrease was linked to increased magnesium adsorption and decreased metal adsorption. The magnitude of effect was related to Mg competitiveness. Sterile plating techniques were used to determine metal lethality. Results did not correspond to respiration results; however, it was demonstrated that copper\u27s effect was lethal while zinc\u27s was inhibitory. Increasing metal concentrations cause toxicity to increases at a decreasing rate only so long as the metal remains in solution. Metals as precipitates are no longer available to adsorb to the cell and do not affect toxicity. Toxicity was shown to be related to metal availability and how well it competed with other cations. Toxicity also depended on cell-ligand competition and how strongly the metal bound itself to the cell
Recent developments in parallel rendering
Journal ArticleUsing parallel computers for computer graphics rendering dates back to the late 1970s. Several papers published then focused on image space decompositions for theoretical parallel machines. Early research concentrated on algorithmic studies and special-purpose hardware, but the growing availability of commercial parallel systems added a new dimension to parallel rendering
Identification and cost of adverse events in metastatic breast cancer in taxane and capecitabine based regimens.
PurposeWe sought to compare the economic impact of treatment-related adverse events (AEs) in patients with metastatic breast cancer (mBC) using taxane- or capecitabine-based treatment regimens as either first- or second-line (FL or SL) therapy in the US.MethodsWe used healthcare claims data from the Truven Health Analytics MarketScan® Commercial Databases to conduct a retrospective cohort study comparing the economic impact of AEs amongst taxane- and capecitabine-treated mBC patients in the US. We selected women diagnosed with mBC between 2008-2010 who received a taxane or capecitabine as first- or second-line (FL or SL) chemotherapy. Costs related to hospitalization, outpatient services, emergency department visits, chemotherapy and other medications were tabulated and combined to determine total healthcare costs. The incremental monthly costs associated with the presence of AEs compared to no AEs were estimated using generalized linear models, controlling for age and Charlson Comorbidity Index.ResultsWe identified 15,443 mBC patients meeting inclusion criteria. Adjusted total monthly costs were significantly higher in those who experienced AEs than in those without AEs in both lines of treatment (FL incremental cost: taxanes 1,817; SL incremental cost: taxanes 4,437). Total costs increased with the number of AEs and were primarily driven by increased hospitalization amongst those with AEs.ConclusionsAdverse events in taxane- or capecitabine-treated mBC patients are associated with significant increases in costs. Selecting treatment options associated with fewer AEs may reduce costs and improve outcomes in these patients
A novel role for the CBF3 kinetochore–scaffold complex in regulating septin dynamics and cytokinesis
In budding yeast, the kinetochore scaffold complex centromere binding factor 3 (CBF3) is required to form kinetochores on centromere DNA and to allow proper chromosome segregation. We have previously shown that SKP1 and SGT1 balance the assembly and turnover of CBF3 complexes, a cycle that we suggest is independent of its role in chromosome segregation (Rodrigo-Brenni, M.C., S. Thomas, D.C. Bouck, and K.B. Kaplan. 2004. Mol. Biol. Cell. 15:3366–3378). We provide evidence that this cycle contributes to a second, kinetochore-independent function of CBF3. In this study, we show that inhibiting the assembly of CBF3 causes disorganized septins and defects in cell polarity that give rise to cytokinesis failures. Specifically, we show that septin ring separation and disassembly is delayed in anaphase, suggesting that CBF3 regulates septin dynamics. Only mutations that affect the CBF3 cycle, and not mutants in outer kinetochore subunits, cause defects in septins. These results demonstrate a novel role for CBF3 in regulating cytokinesis, a role that is reminiscent of passenger proteins. Consistent with this possibility, we find that CBF3 interacts with Bir1p, the homologue of the passenger protein Survivin. Mutants in Bir1p similarly affect septin organization, leading us to propose that CBF3 and Bir1p act as passenger proteins to coordinate chromosome segregation with cytokinesis
Dimensional analysis of acoustically propagated signals
Traditionally, long term measurements of atmospherically propagated sound signals have consisted of time series of multiminute averages. Only recently have continuous measurements with temporal resolution corresponding to turbulent time scales been available. With modern digital data acquisition systems we now have the capability to simultaneously record both acoustical and meteorological parameters with sufficient temporal resolution to allow us to examine in detail relationships between fluctuating sound and the meteorological variables, particularly wind and temperature, which locally determine the acoustic refractive index. The atmospheric acoustic propagation medium can be treated as a nonlinear dynamical system, a kind of signal processor whose innards depend on thermodynamic and turbulent processes in the atmosphere. The atmosphere is an inherently nonlinear dynamical system. In fact one simple model of atmospheric convection, the Lorenz system, may well be the most widely studied of all dynamical systems. In this paper we report some results of our having applied methods used to characterize nonlinear dynamical systems to study the characteristics of acoustical signals propagated through the atmosphere. For example, we investigate whether or not it is possible to parameterize signal fluctuations in terms of fractal dimensions. For time series one such parameter is the limit capacity dimension. Nicolis and Nicolis were among the first to use the kind of methods we have to study the properties of low dimension global attractors
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WH2 and proline-rich domains of WASP-family proteins collaborate to accelerate actin filament elongation.
WASP-family proteins are known to promote assembly of branched actin networks by stimulating the filament-nucleating activity of the Arp2/3 complex. Here, we show that WASP-family proteins also function as polymerases that accelerate elongation of uncapped actin filaments. When clustered on a surface, WASP-family proteins can drive branched actin networks to grow much faster than they could by direct incorporation of soluble monomers. This polymerase activity arises from the coordinated action of two regulatory sequences: (i) a WASP homology 2 (WH2) domain that binds actin, and (ii) a proline-rich sequence that binds profilin-actin complexes. In the absence of profilin, WH2 domains are sufficient to accelerate filament elongation, but in the presence of profilin, proline-rich sequences are required to support polymerase activity by (i) bringing polymerization-competent actin monomers in proximity to growing filament ends, and (ii) promoting shuttling of actin monomers from profilin-actin complexes onto nearby WH2 domains. Unoccupied WH2 domains transiently associate with free filament ends, preventing their growth and dynamically tethering the branched actin network to the WASP-family proteins that create it. Collaboration between WH2 and proline-rich sequences thus strikes a balance between filament growth and tethering. Our work expands the number of critical roles that WASP-family proteins play in the assembly of branched actin networks to at least three: (i) promoting dendritic nucleation; (ii) linking actin networks to membranes; and (iii) accelerating filament elongation
Chromosome passenger complexes control anaphase duration and spindle elongation via a kinesin-5 brake
Chromosome passenger complexes and bipolar kinesins act together to coordinate spindle elongation, spindle breakdown, and mitotic exit
The effect of vertical prism induced stress on the accommodation and vergence ranges
This paper presents a study of the effect a vertical imbalance has on the lateral vergence and accommodation ranges as measured in standard clinical testing. The clinical tests included lateral duction ranges at 6 meters and 40 centimeters, the positive relative accommodation (PRA), and the negative relative accommodation (NRA). Nineteen subjects considered visually normal were tested once with two prism diopters of induced vertical imbalance, and once under normal conditions. An ANOV A was performed on the means of thirteen clinical tests . The F-test and probability values are also presented . Results indicate that the findings of the tests with the vertical prism in place were not different from the findings with no pr ism in place
Climate Variability and Water Infrastructure: Historical Experience in the Western United States
Greater historical perspective is needed to enlighten current debate about future human responses to higher temperatures and increased precipitation variation. We analyze the impact of climatic conditions and variability on agricultural production in five semi-arid western states. We assemble county-level data on dams and other major water infrastructure; agricultural crop mixes and yields; precipitation and temperature; soil quality, and topography. Using this extensive data set, we analyze the impact of water infrastructure investments on crop mix and yields in affected counties relative to similarly-endowed counties that lack such infrastructure. We find that water infrastructure smoothes agricultural crop production and increases the likelihood of a successful harvest, especially during times of severe drought or excessive precipitation.
Misdiagnosis, Mistreatment, and Harm - When Medical Care Ignores Social Forces.
The Case Studies in Social Medicine demonstrate that when physicians use only biologic or individual behavioral interventions to treat diseases that stem from or are exacerbated by social factors, we risk harming the patients we seek to serve
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