313 research outputs found
Organometallic 3-(1H-Benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines as Potential Anticancer Agents
Evaluating the Community Land Model (CLM4.5) at a coniferous forest site in northwestern United States using flux and carbon-isotope measurements
Droughts in the western United States are expected to intensify with climate
change. Thus, an adequate representation of ecosystem response to water
stress in land models is critical for predicting carbon dynamics. The goal of
this study was to evaluate the performance of the Community Land Model (CLM)
version 4.5 against observations at an old-growth coniferous forest site in
the Pacific Northwest region of the United States (Wind River AmeriFlux
site), characterized by a Mediterranean climate that subjects trees to water
stress each summer. CLM was driven by site-observed meteorology and
calibrated primarily using parameter values observed at the site or at
similar stands in the region. Key model adjustments included parameters
controlling specific leaf area and stomatal conductance. Default values of
these parameters led to significant underestimation of gross primary
production, overestimation of evapotranspiration, and consequently
overestimation of photosynthetic 13C discrimination, reflected in
reduced 13C : 12C ratios of carbon fluxes and pools. Adjustments
in soil hydraulic parameters within CLM were also critical, preventing
significant underestimation of soil water content and unrealistic soil
moisture stress during summer. After calibration, CLM was able to simulate
energy and carbon fluxes, leaf area index, biomass stocks, and carbon isotope
ratios of carbon fluxes and pools in reasonable agreement with site
observations. Overall, the calibrated CLM was able to simulate the observed
response of canopy conductance to atmospheric vapor pressure deficit (VPD)
and soil water content, reasonably capturing the impact of water stress on
ecosystem functioning. Both simulations and observations indicate that
stomatal response from water stress at Wind River was primarily driven by VPD
and not soil moisture. The calibration of the Ball–Berry stomatal
conductance slope (mbb) at Wind River aligned with findings from recent CLM experiments at sites characterized by the same plant functional
type (needleleaf evergreen temperate forest), despite significant differences
in stand composition and age and climatology, suggesting that CLM could
benefit from a revised mbb value of 6, rather than the default
value of 9, for this plant functional type. Conversely, Wind River required a
unique calibration of the hydrology submodel to simulate soil moisture,
suggesting that the default hydrology has a more limited applicability. This
study demonstrates that carbon isotope data can be used to constrain stomatal
conductance and intrinsic water use efficiency in CLM, as an alternative to
eddy covariance flux measurements. It also demonstrates that carbon isotopes
can expose structural weaknesses in the model and provide a key constraint
that may guide future model development
Out of the wave: The meaning of suffering and relief from suffering as described in autobiographies by survivors of the 2004 Indian Ocean tsunami
The aim of this study was to explore the meaning of suffering and relief from suffering as described in autobiographies by tourists who experienced the tsunami on 26 December 2004 and lost loved ones. A lifeworld approach, inspired by the French philosopher Merleau-Ponty's phenomenology of perception, was chosen for the theoretical framework. This catastrophe totally changed the survivors' world within a moment. In this new world, there were three main phases: the power of remaining focused, a life of despair, and the unbearable becoming bearable. Life turns into a matter of making the unbearable bearable. Such challenging experiences are discussed in terms of the philosophy of Weil, Jaspers, and Merleau-Ponty. The survivors of the tsunami catastrophe were facing a boundary situation and “le malheur,” the unthinkable misfortune. Even at this lowest level of misfortune, joy is possible to experience. This is part of the survivors' ambivalent experiences of their lifeworld. In this world of the uttermost despair there are also rays of hope, joy, and new life possibilities
The effects of a three-week use of lumbosacral orthoses on trunk muscle activity and on the muscular response to trunk perturbations
<p>Abstract</p> <p>Background</p> <p>The effects of lumbosacral orthoses (LSOs) on neuromuscular control of the trunk are not known. There is a concern that wearing LSOs for a long period may adversely alter muscle control, making individuals more susceptible to injury if they discontinue wearing the LSOs. The purpose of this study was to document neuromuscular changes in healthy subjects during a 3-week period while they regularly wore a LSO.</p> <p>Methods</p> <p>Fourteen subjects wore LSOs 3 hrs a day for 3 weeks. Trunk muscle activity prior to and following a quick force release (trunk perturbation) was measured with EMG in 3 sessions on days 0, 7, and 21. A longitudinal, repeated-measures, factorial design was used. Muscle reflex response to trunk perturbations, spine compression force, as well as effective trunk stiffness and damping were dependent variables. The LSO, direction of perturbation, and testing session were the independent variables.</p> <p>Results</p> <p>The LSO significantly (<it>P </it>< 0.001) increased the effective trunk stiffness by 160 Nm/rad (27%) across all directions and testing sessions. The number of antagonist muscles that responded with an onset activity was significantly reduced after 7 days of wearing the LSO, but this difference disappeared on day 21 and is likely not clinically relevant. The average number of agonist muscles switching off following the quick force release was significantly greater with the LSO, compared to without the LSO (<it>P </it>= 0.003).</p> <p>Conclusions</p> <p>The LSO increased trunk stiffness and resulted in a greater number of agonist muscles shutting-off in response to a quick force release. However, these effects did not result in detrimental changes to the neuromuscular function of trunk muscles after 3 weeks of wearing a LSO 3 hours a day by healthy subjects.</p
Implementation of a standardized protocol to manage elderly patients with low energy pelvic fractures: can service improvement be expected?
Purpose: The incidence of low energy pelvic fractures (FPFs) in the elderly is increasing. Comorbidities, decreased bone-quality, problematic fracture fixation and poor compliance represent some of their specific difficulties. In the absence of uniform management, a standard operating procedure (SOP) was introduced to our unit, aiming to improve the quality of services provided to these patients. Methods: A cohort study was contacted to test the impact of (1) using a specific clinical algorithm and (2) using different antiosteoporotic drugs. Multivariate regression analysis was used to determine prognostic factors. Study endpoints were the time-to-healing, length-of-stay, return to pre-injury mobility, union status, mortality and complications. Results: A total of 132 elderly patients (≥65 years) admitted during the period 2012–2014 with FPFs were enrolled. High-energy fractures, acetabular fractures, associated trauma affecting mobility, pathological pelvic lesions and operated FPFs were used as exclusion criteria. The majority of included patients were females (108/132; 81.8%), and the mean age was 85.8 years (range 67–108). Use of antiosteoporotics was associated with a shorter time of healing (p = 0.036). Patients treated according to the algorithm showed a significant protection against malunion (p < 0.001). Also, adherence to the algorithm allowed more patients to return to their pre-injury mobility status (p = 0.039). Conclusions: The use of antiosteoporotic medication in elderly patients with fragility pelvic fractures was associated with faster healing, whilst the adherence to a structured clinical pathway led to less malunions and non-unions and return to pre-injury mobility state
Potent interaction of flavopiridol with MRP1
The multidrug resistance protein 1 (MRP1) is an ATP-dependent transport protein for organic anions, as well as neutral or positively charged anticancer agents. In this study we show that flavopiridol, a synthetic flavonoid currently studied in phase 1 trials for its anti-proliferative characteristics, interacts with MRP1 in a potent way. Flavopiridol, as well as other (iso)flavonoids stimulate the ATPase activity of MRP1 in a dose-dependent way at low micromolar concentrations. A new specific monoclonal antibody against MRP1 (MIB6) inhibits the (iso)flavonoid-induced ATPase activity of plasma membrane vesicles prepared from the MRP1 overexpressing cell line GLC4/ADR. The accumulation of daunorubicin in GLC4/ADR cells is increased by flavopiridol and by other non-glycosylated (iso)flavonoids that interact with MRP1 ATPase activity. However, flavopiridol is the only tested compound that affects the daunorubicin accumulation when present at concentrations below 1 μM. Glycosylated (iso)flavonoids do not affect MRP1-mediated transport or ATPase activity. Finally, MRP1 overexpressing and transfected cells are resistant to flavopiridol, but not to other (iso)flavonoids tested. These findings may be of relevance for the development of anticancer therapies with flavopiridol. © 1999 Cancer Research Campaig
The cyclin-dependent kinase inhibitor 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole induces nongenotoxic, DNA replication-independent apoptosis of normal and leukemic cells, regardless of their p53 status
<p>Abstract</p> <p>Background</p> <p>Current chemotherapy of human cancers focuses on the DNA damage pathway to induce a p53-mediated cellular response leading to either G1 arrest or apoptosis. However, genotoxic treatments may induce mutations and translocations that result in secondary malignancies or recurrent disease. In addition, about 50% of human cancers are associated with mutations in the <it>p53 </it>gene. Nongenotoxic activation of apoptosis by targeting specific molecular pathways thus provides an attractive therapeutic approach.</p> <p>Methods</p> <p>Normal and leukemic cells were evaluated for their sensitivity to 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) through cell viability and caspase activation tests. The apoptotic pathway induced by DRB was analysed by immunfluorescence and immunoblot analysis. H2AX phosphorylation and cell cycle analysis were performed to study the dependance of apoptosis on DNA damage and DNA replication, respectively. To investigate the role of p53 in DRB-induced apoptosis, specific p53 inhibitors were used. Statistical analysis on cell survival was performed with the test of independence.</p> <p>Results</p> <p>Here we report that DRB, an inhibitor of the transcriptional cyclin-dependent kinases (CDKs) 7 and 9, triggers DNA replication-independent apoptosis in normal and leukemic human cells regardless of their p53 status and without inducing DNA damage. Our data indicate that (i) in p53-competent cells, apoptosis induced by DRB relies on a cytosolic accumulation of p53 and subsequent Bax activation, (ii) in the absence of p53, it may rely on p73, and (iii) it is independent of ATM and NBS1 proteins. Notably, even apoptosis-resistant leukemic cells such as Raji were sensitive to DRB.</p> <p>Conclusion</p> <p>Our results indicate that DRB represents a potentially useful cancer chemotherapeutic strategy that employs both the p53-dependent and -independent apoptotic pathways without inducing genotoxic stress, thereby decreasing the risk of secondary malignancies.</p
Characterization of an Outbreak of Hand, Foot, and Mouth Disease in Nanchang, China in 2010
Recent outbreaks of human enterovirus 71 (EV71) infection and EV71-associated hand, foot, and mouth disease (HFMD) in China have affected millions and potentially lead to life-threatening complications in newborns. Furthermore, these outbreaks represent a significant global public health issue in the world. Understanding the epidemiology of HFMD and EV71 infection and their transmission patterns in China is essential for controlling outbreaks. However, no studies on the outbreaks of HFMD and EV71 infection in China during 2010 have been reported. In this report, we carried out an epidemiological analysis to study an outbreak of HFMD and EV71 infection in 2010 in the city of Nanchang in the Jiangxi province of People's Republic of China. From April 7 to May 11, 2010, a total of 109 HFMD cases were reported, and in this report the HFMD cases were studied by both epidemiological and laboratory analyses. The epidemiological study indicates that children aged younger than 8 years old represented more than 90% of the reported cases, with the age group of 1–3 years containing the highest number of cases. Laboratory studies detected a high prevalence of EV71 amongst the cases in our study, suggesting EV71 as a common enterovirus found in HFMD cases in Nanchang. Phylogenetic analysis of the sequence of the VP1 region of four EV71 isolates indicated that the Nanchang strains belong to the C4 subgenotype commonly found in China during outbreaks in 2008 but contain distinct variations from these strains. Our study for the first time characterizes the epidemiology of HFMD and EV71 infection in China in 2010 and furthermore, provides the first direct evidence of the genotype of EV71 circulating in Nanchang, China. Our study should facilitate the development of public health measures for the control and prevention of HFMD and EV71 infection in at-risk individuals in China
Studying the co-evolution of production and test code in open source and industrial developer test processes through repository mining
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