Group Strategyproof Pareto-Stable Marriage with Indifferences via the Generalized Assignment Game

We study the variant of the stable marriage problem in which the preferences of the agents are allowed to include indifferences. We present a mechanism for producing Pareto-stable matchings in stable marriage markets with indifferences that is group strategyproof for one side of the market. Our key technique involves modeling the stable marriage market as a generalized assignment game. We also show that our mechanism can be implemented efficiently. These results can be extended to the college admissions problem with indifferences

In vitro inhibition of 10-formyltetrahydrofolate dehydrogenase activity by acetaldehyde

Alcoholism has been associated with folate deficiency in humans and laboratory animals. Previous study showed that ethanol feeding reduces the dehydrogenase and hydrolase activity of 10-formyltetrahydrofolate dehydrogenase (FDH) in rat liver. Hepatic ethanol metabolism generates acetaldehyde and acetate. The mechanisms by which ethanol and its metabolites produce toxicity within the liver cells are unknown. We purified FDH from rat liver and investigated the effect of ethanol, acetaldehyde and acetate on the enzyme in vitro. Hepatic FDH activity was not reduced by ethanol or acetate directly. However, acetaldehyde was observed to reduce the dehydrogenase activity of FDH in a dose- and time-dependent manner with an apparent IC50 of 4 mM, while the hydrolase activity of FDH was not affected by acetaldehyde in vitro. These results suggest that the inhibition of hepatic FDH dehydrogenase activity induced by acetadehyde may play a role in ethanol toxicity

What Facilitates Return to Work? Patients Experiences 3 Years After Occupational Rehabilitation

Objective We have limited knowledge about the specific elements in an occupational rehabilitation programme that facilitate the process leading to return to work (RTW) as perceived by the patients. The aim of the study was to explore individual experiences regarding contributing factors to a successful RTW, 3 years after a resident occupational rehabilitation programme. Methods The study is based on interviews of 20 individuals who attended an occupational rehabilitation programme 3 years earlier. Ten informants had returned to work (RTW) and ten were receiving disability pension (DP). Data were analysed by systematic text condensation inspired by Giorgi’s phenomenological analysis. Results The core categories describing a successful RTW process included positive encounters, increased self-understanding and support from the surroundings. While the informants on DP emphasized being seen, heard and taken seriously by the professionals, the RTW group highlighted being challenged to increase self-understanding that promoted new acting in every-day life. Being challenged on self-understanding implied increased awareness of own identity, values and resources. Support from the surroundings included support from peer participants, employer and social welfare system. Conclusion Successful RTW processes seem to comprise positive encounters, opportunities for increased self-understanding and support from significant others. An explicit focus on topics like identity, own values and resources might improve the outcome of the rehabilitation process

Quantification and visualization of cardiovascular 4D velocity mapping accelerated with parallel imaging or k-t BLAST: head to head comparison and validation at 1.5 T and 3 T

<p>Abstract</p> <p>Background</p> <p>Three-dimensional time-resolved (4D) phase-contrast (PC) CMR can visualize and quantify cardiovascular flow but is hampered by long acquisition times. Acceleration with SENSE or k-t BLAST are two possibilities but results on validation are lacking, especially at 3 T. The aim of this study was therefore to validate quantitative in vivo cardiac 4D-acquisitions accelerated with parallel imaging and k-t BLAST at 1.5 T and 3 T with 2D-flow as the reference and to investigate if field strengths and type of acceleration have major effects on intracardiac flow visualization.</p> <p>Methods</p> <p>The local ethical committee approved the study. 13 healthy volunteers were scanned at both 1.5 T and 3 T in random order with 2D-flow of the aorta and main pulmonary artery and two 4D-flow sequences of the heart accelerated with SENSE and k-t BLAST respectively. 2D-image planes were reconstructed at the aortic and pulmonary outflow. Flow curves were calculated and peak flows and stroke volumes (SV) compared to the results from 2D-flow acquisitions. Intra-cardiac flow was visualized using particle tracing and image quality based on the flow patterns of the particles was graded using a four-point scale.</p> <p>Results</p> <p>Good accuracy of SV quantification was found using 3 T 4D-SENSE (r²= 0.86, -0.7 ± 7.6%) and although a larger bias was found on 1.5 T (r²= 0.71, -3.6 ± 14.8%), the difference was not significant (p = 0.46). Accuracy of 4D k-t BLAST for SV was lower (p < 0.01) on 1.5 T (r²= 0.65, -15.6 ± 13.7%) compared to 3 T (r²= 0.64, -4.6 ± 10.0%). Peak flow was lower with 4D-SENSE at both 3 T and 1.5 T compared to 2D-flow (p < 0.01) and even lower with 4D k-t BLAST at both scanners (p < 0.01). Intracardiac flow visualization did not differ between 1.5 T and 3 T (p = 0.09) or between 4D-SENSE or 4D k-t BLAST (p = 0.85).</p> <p>Conclusions</p> <p>The present study showed that quantitative 4D flow accelerated with SENSE has good accuracy at 3 T and compares favourably to 1.5 T. 4D flow accelerated with k-t BLAST underestimate flow velocities and thereby yield too high bias for intra-cardiac quantitative in vivo use at the present time. For intra-cardiac 4D-flow visualization, however, 1.5 T and 3 T as well as SENSE or k-t BLAST can be used with similar quality.</p

Systematically missing confounders in individual participant data meta-analysis of observational cohort studies.

One difficulty in performing meta-analyses of observational cohort studies is that the availability of confounders may vary between cohorts, so that some cohorts provide fully adjusted analyses while others only provide partially adjusted analyses. Commonly, analyses of the association between an exposure and disease either are restricted to cohorts with full confounder information, or use all cohorts but do not fully adjust for confounding. We propose using a bivariate random-effects meta-analysis model to use information from all available cohorts while still adjusting for all the potential confounders. Our method uses both the fully adjusted and the partially adjusted estimated effects in the cohorts with full confounder information, together with an estimate of their within-cohort correlation. The method is applied to estimate the association between fibrinogen level and coronary heart disease incidence using data from 154,012 participants in 31 cohort

Improved Heterosis Prediction by Combining Information on DNA- and Metabolic Markers

Background: Hybrids represent a cornerstone in the success story of breeding programs. The fundamental principle underlying this success is the phenomenon of hybrid vigour, or heterosis. It describes an advantage of the offspring as compared to the two parental lines with respect to parameters such as growth and resistance against abiotic or biotic stress. Dominance, overdominance or epistasis based models are commonly used explanations. Conclusion/Significance: The heterosis level is clearly a function of the combination of the parents used for offspring production. This results in a major challenge for plant breeders, as usually several thousand combinations of parents have to be tested for identifying the best combinations. Thus, any approach to reliably predict heterosis levels based on properties of the parental lines would be highly beneficial for plant breeding. Methodology/Principal Findings: Recently, genetic data have been used to predict heterosis. Here we show that a combination of parental genetic and metabolic markers, identified via feature selection and minimum-description-length based regression methods, significantly improves the prediction of biomass heterosis in resulting offspring. These findings will help furthering our understanding of the molecular basis of heterosis, revealing, for instance, the presence of nonlinear genotype-phenotype relationships. In addition, we describe a possible approach for accelerated selection in plant breeding

Early start and stop of biologics: has the time come?

Despite considerable advances in the management of rheumatoid arthritis, results are still not satisfactory for all patients. The treatment goal in rheumatoid arthritis is remission, and there currently are numerous conventional and biological medications available to reach this aim. There are also different treatment strategies but with only limited comparative evidence about their efficacies. More patients now achieve remission while on treatment, but it remains elusive in the majority of patients. Treatment-free remission, the ultimate goal of therapy, is only achieved in very few patients; even when this happens, it is most likely due to the natural course of the disease rather than to any specific therapies. Modern treatment is based on the initiation of aggressive therapy as soon as the diagnosis is established, and on modifying or intensifying therapy guided by frequent assessment of disease activity. In this commentary we will discuss the current treatment paradigm as well as the possibility of an induction-maintenance regimen with biological disease-modifying antirheumatic drugs in early rheumatoid arthriti

Plasmodium vivax: paroxysm-associated lipids mediate leukocyte aggregation

<p>Abstract</p> <p>Background</p> <p>Paroxysms are recurrent febrile episodes, characteristic of <it>Plasmodium vivax </it>infections, which coincide with the rupture of schizont-infected erythrocytes in the patients' circulation. The present study describes the formation of prominent aggregates of leukocytes <it>in vitro </it>in the presence of parasite and host factors released during paroxysms.</p> <p>Methods</p> <p>Whole blood cells from uninfected malaria-naïve donors were incubated with plasma taken during a paroxysm or normal human plasma as a control and cell smears were observed under the microscope for the presence of leukocyte aggregates. Plasma factors involved in mediating the leukocyte aggregation were identified using immune depletion and reconstitution experiments. Furthermore, biochemical characterization was carried out to determine the chemical nature of the active moieties in plasma present during paroxysms.</p> <p>Results</p> <p>Leukocyte aggregates were seen exclusively when cells were incubated in plasma collected during a paroxysm. Immune depletion and reconstitution experiments revealed that the host cytokines TNF-alpha, GM-CSF, IL-6 and IL-10 and two lipid fractions of paroxysm plasma comprise the necessary and sufficient mediators of this phenomenon. The two lipid components of the paroxysm plasmas speculated to be of putative parasite origin, were a phospholipid-containing fraction and another containing cholesterol and triglycerides. The phospholipid fraction was dependent upon the presence of cytokines for its activity unlike the cholesterol/triglyceride-containing fraction which in the absence of added cytokines was much more active than the phospholipids fraction. The biological activity of the paroxysm plasmas from non-immune patients who presented with acute <it>P. vivax </it>infections was neutralized by immune sera raised against schizont extracts of either <it>P. vivax </it>or <it>Plasmodium falciparum</it>. However, immune sera against <it>P. vivax </it>were more effective than that against <it>P. falciparum </it>indicating that the parasite activity involved may be antigenically at least partially parasite species-specific.</p> <p>Conclusion</p> <p>Leukocyte aggregation was identified as associated with paroxysms in <it>P. vivax </it>infections. This phenomenon is mediated by plasma factors including host-derived cytokines and lipids of putative parasite origin. The characteristics of the phospholipid fraction in paroxysm plasma are congruent with those of the parasite-derived, TNF-inducing GPI moieties described by others. The more active cholesterol/triglyceride(s), however, represent a novel malarial toxin, which is a new class of biologically active lipid associated with the paroxysm of <it>P. vivax </it>malaria.</p