The dosimetric effects from the jaw positioned close to the small field (
0.5
×
0.5
,
1
×
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, and
2
×
2
cm
2
) side-edge generated by a single-focused multileaf collimator (MLC) were measured and ...studied. The measurement is important in intensity modulated radiotherapy (IMRT) because generally the jaw cannot perfectly cover all the leaf-ends in a segment of irregular field. This leads to additional dose contributed by (1) the end surface of the jaw, (2) the leaf-end, and (3) the inter- and intraleaf leakage/transmissions during the dosimetric measurement. Moreover, most of the conventional treatment planning systems ignore these effects in the dose calculation. In this study, measurements were made using a Varian 21 EX linear accelerator with 6 MV photon beam through a MLC containing 120 leaves. Percentage depth dose, beam profile, and output for small fields were measured by varying the jaw at different positions away from the leaf-ends in the field side-edge. Moving the jaw away from the leaf-ends increases the output and penumbra width for the small fields. Such increase is particularly significant when the field size is small
(
0.5
×
0.5
cm
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)
and the degree of increase changes quickly when the jaw-end is at about 1–2 cm from the leaf-end. It is suggested that measurements should be carried out in the IMRT commissioning to provide information to physicists in reviewing the treatment planning system’s accuracy regarding leaf leakage/transmission and jaw effects.
Purpose
Mycorrhizal fungi are critical for the growth and survival of trees although the knowledge on the extent of their association with different tree species in the boreal forest remains limited.
...Methods
We examined the vertical distribution and composition of the root mycorrhizal communities of black spruce (
Picea mariana
(Mill.) B.S.P) and trembling aspen (
Populus tremuloides
Michx) along three soil layers (organic, minerals top 0–15 cm and bottom 15–30 cm) in pure and mixed stands, using next generation sequencing.
Results
We found that spruce and aspen differ in the composition of their mycorrhizal communities in respective pure stands. The difference was present also in mixed stands, despite a shift in the composition of species-specific mycorrhizal communities between pure and mixed stands. In mixed stands, the relative abundance of spruce-specialist mycorrhizae in the organic layer was higher than that of aspen-specialists. The opposite pattern was observed in the mineral soil. The mixed stands exhibited lower richness and abundance of generalist mycorrhizae in the organic and in the mineral soil layers.
Conclusion
The results suggest that it is the soil chemistry that structure species-specific mycorrhizal communities between pure stands and along different soil depth within stands. However, in mixed stands, it is the identity of tree species that determines the structure of mycorrhizae communities within soil layers. We speculate that the differences in the richness and abundance of individual mycorrhizal communities of spruce and aspen along the soil profile would likely contribute to stronger partitioning of tree nutrient uptake between these two species in mixed stands.
An increased proportion of deaths occur in the intensive care unit (ICU). We performed this prospective study in 41 ICUs to determine the prevalence and determinants of complicated grief after death ...of a loved one in the ICU. Relatives of 475 adult patients were followed up. Complicated grief was assessed at 6 and 12 months using the Inventory of Complicated Grief (cut-off score >25). Relatives also completed the Hospital Anxiety and Depression Scale at 3 months, and the Revised Impact of Event Scale for post-traumatic stress disorder symptoms at 3, 6 and 12 months. We used a mixed multivariate logistic regression model to identify determinants of complicated grief after 6 months. Among the 475 patients, 282 (59.4%) had a relative evaluated at 6 months. Complicated grief symptoms were identified in 147 (52%) relatives. Independent determinants of complicated grief symptoms were either not amenable to changes (relative of female sex, relative living alone and intensivist board certification before 2009) or potential targets for improvements (refusal of treatment by the patient, patient died while intubated, relatives present at the time of death, relatives did not say goodbye to the patient, and poor communication between physicians and relatives). End-of-life practices, communication and loneliness in bereaved relatives may be amenable to improvements.
Little is known about differential suicide profiles across the life trajectory. This study introduces the life-course method in suicide research with the aim of refining the longitudinal and ...cumulative assessment of psychosocial factors by quantifying accumulation of burden over time in order to delineate distinctive pathways of completed suicide.
The psychological autopsy method was used to obtain third-party information on consecutive suicides. Life-history calendar analysis served to arrive at an adversity score per 5-year segment that was then cluster-analysed and correlated to define victim profiles.
Two distinct life trajectories emerged: (1) individuals who experienced childhood traumas, developmental adversity and little protection were more likely to present concurrent psychiatric and Axis II disorders; and (2) individuals who experienced less adversity but seemed more reactive to later major difficulties.
The life calendar approach presented here in suicide research adds to the identification of life events, distal and recent, previously associated with suicide. It also quantifies the burden of adversity over the life course, defining two distinct profiles that could benefit from distinct targeted preventive intervention.
The extraembryonic endoderm of mammals is essential for nutritive support of the fetus and patterning of the early embryo. Visceral and parietal endoderm are major subtypes of this lineage with the ...former exhibiting most, if not all, of the embryonic patterning properties. Extraembryonic endoderm (XEN) cell lines derived from the primitive endoderm of mouse blastocysts represent a cell culture model of this lineage, but are biased towards parietal endoderm in culture and in chimeras. In an effort to promote XEN cells to adopt visceral endoderm character we have mimicked different aspects of the in vivo environment. We found that BMP signaling promoted a mesenchymal-to-epithelial transition of XEN cells with up-regulation of E-cadherin and down-regulation of vimentin. Gene expression analysis showed the differentiated XEN cells most resembled extraembryonic visceral endoderm (exVE), a subtype of VE covering the extraembryonic ectoderm in the early embryo, and during gastrulation it combines with extraembryonic mesoderm to form the definitive yolk sac. We found that laminin, a major component of the extracellular matrix in the early embryo, synergised with BMP to promote highly efficient conversion of XEN cells to exVE. Inhibition of BMP signaling with the chemical inhibitor, Dorsomorphin, prevented this conversion suggesting that Smad1/5/8 activity is critical for exVE induction of XEN cells. Finally, we show that applying our new culture conditions to freshly isolated parietal endoderm (PE) from Reichert's membrane promoted VE differentiation showing that the PE is developmentally plastic and can be reprogrammed to a VE state in response to BMP. Generation of visceral endoderm from XEN cells uncovers the true potential of these blastocyst-derived cells and is a significant step towards modelling early developmental events
ex vivo.
► XEN cells can be differentiated into extraembryonic visceral endoderm by BMP4. ► Laminin enhances the ability of BMP4 to promote visceral endoderm differentiation of XEN cells. ► Parietal endoderm is developmentally plastic, and can be induced to form visceral endoderm in response to BMP signaling.
High‐throughput sequencing has dramatically fostered ancient DNA research in recent years. Shotgun sequencing, however, does not necessarily appear as the best‐suited approach due to the extensive ...contamination of samples with exogenous environmental microbial DNA. DNA capture‐enrichment methods represent cost‐effective alternatives that increase the sequencing focus on the endogenous fraction, whether it is from mitochondrial or nuclear genomes, or parts thereof. Here, we explored experimental parameters that could impact the efficacy of MYbaits in‐solution capture assays of ~5000 nuclear loci or the whole genome. We found that varying quantities of the starting probes had only moderate effect on capture outcomes. Starting DNA, probe tiling, the hybridization temperature and the proportion of endogenous DNA all affected the assay, however. Additionally, probe features such as their GC content, number of CpG dinucleotides, sequence complexity and entropy and self‐annealing properties need to be carefully addressed during the design stage of the capture assay. The experimental conditions and probe molecular features identified in this study will improve the recovery of genetic information extracted from degraded and ancient remains.
Autoimmune thrombotic thrombocytopenic purpura (TTP) can be associated with other autoimmune disorders, but their prevalence following autoimmune TTP remains unknown. To assess the prevalence of ...autoimmune disorders associated with TTP and to determine risk factors for and the time course of the development of an autoimmune disorder after a TTP episode, we performed a cross sectional study. Two-hundred sixty-one cases of autoimmune TTP were included in the French Reference Center registry between October, 2000 and May, 2009. Clinical and laboratory data available at time of TTP diagnosis were recovered. Each center was contacted to collect the more recent data and diagnosis criteria for autoimmunity. Fifty-six patients presented an autoimmune disorder in association with TTP, 9 years before TTP (median; min: 2 yr, max: 32 yr) (26 cases), at the time of TTP diagnosis (17 cases) or during follow-up (17 cases), up to 12 years after TTP diagnosis (mean, 22 mo). The most frequent autoimmune disorder reported was systemic lupus erythematosus (SLE) (26 cases) and Sjögren syndrome (8 cases). The presence of additional autoimmune disorders had no impact on outcomes of an acute TTP or the occurrence of relapse. Two factors evaluated at TTP diagnosis were significantly associated with the development of an autoimmune disorder during follow-up: the presence of antidouble stranded (ds)DNA antibodies (hazard ratio (HR): 4.98; 95% confidence interval (CI) 1.64-15.14) and anti-SSA antibodies (HR: 9.98; 95% CI 3.59-27.76). A follow-up across many years is necessary after an acute TTP, especially when anti-SSA or anti-dsDNA antibodies are present on TTP diagnosis, to detect autoimmune disorders early before immunologic events spread to prevent disabling complications.
En France, certains auteurs identifient le milieu de travail comme cause exclusive, sinon essentielle, de suicides sur le lieu de travail. Néanmoins, ces interprétations ne sont pas retrouvées dans ...des études empiriques et épidémiologiques.
Nous avons étudié dans quelle mesure les difficultés professionnelles peuvent contribuer à un fardeau d’adversité qui contribue à augmenter la vulnérabilité suicidaire.
Quatre-vingt-quatre participants, la moitié décédée d’un suicide, en emploi au moment du décès et l’autre moitié en vie et en emploi, ont été recrutés afin de comparer les parcours de vie professionnelle, les tentatives de suicide antérieures et le profil psychiatrique. Les données ont été récoltées selon une méthode d’autopsie psychologique et de calendrier de vie explorant toutes les sphères de vie.
Significativement plus de diagnostics d’un trouble des axes I et II, de comorbidités des axes et de tentatives de suicide sont observés parmi les participants décédés par suicide. De plus, les participants vivants ont rencontré significativement plus d’adversité dans le domaine professionnel au cours de la vie et des cinq dernières années.
Des difficultés professionnelles ne constituent pas un facteur de risque aussi robuste que des troubles psychiatriques. Une application possible est d’orienter l’action contre le suicide par le développement de programmes de prévention de la santé mentale, adaptés à des environnements professionnels.
Over 900,000 people die by suicide every year around the world. Suicide has been described as being a multidimensional act, resulting from a number of risk factors accumulating throughout the life course. Recently, in France, some authors have suggested that work environment is a major or a unique risk factor in the etiology of suicide death. This theoretical position is in contradiction with empirical and epidemiologic evidence.
On the base of data from life trajectories, we studied to which extent work difficulties may contribute to a burden of adversity, which contribute to suicidal vulnerability.
Two groups of participants (n=84) were compared. Half (n=42) were suicide victims who were compared to (n=42) living controls. The individuals from the suicide group were employed at the moment of death and the living controls were employed at the moment of the study. Characteristics of participants were compared in regards to life trajectories (love relationships, social interactions, professional difficulties), past suicide attempts and psychiatric diagnosis. Data were collected according to a psychological autopsy and life calendar methods.
Significantly more mental health disorders on axis I (DSM-IV), especially mood and substances disorders as well as disorders on axis II (especially Cluster C) were observed among deceased participants. Moreover, comorbid mental health disorders and past suicide attempts over the life course were significantly more prevalent among participants deceased by suicide. No significant differences are observed between groups concerning adversities in love relationships and social interactions. However, participants from the control group had significantly more adversities in professional domain over the life course and during the last 5 years.
Work difficulties are not a robust or direct risk factor of suicide, but psychiatric disorders are. These results are in contradiction with opinions of a debate in France concerning a direct link between work and suicides and should foster new debate. Application should promote the development of suicide prevention programs in work environments by focusing on protection and promotion the psychological health of workers.
Le but de l’article est de présenter les résultats d’un consortium d’experts désignés par le Centre d’expertise Marie-Vincent. Le mandat du consortium était d’évaluer l’état des connaissances sur les ...agressions sexuelles envers les enfants âgés de 5 ans et moins. Cette synthèse met en lumière les défis liés au dépistage, aux enquêtes et à l’évaluation de l’agression sexuelle chez les jeunes enfants. Le manque important de connaissances à ce sujet limite le développement de cadres de référence pour orienter les stratégies de prévention et d’intervention, qui pourtant s’avèrent essentielles pour contribuer au mieux-être des jeunes victimes et de leurs familles.
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