683 research outputs found

    The performance of yields in organic and conventional cropping systems

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    Sufficient and stable crop yields are the basis for feeding a growing world population. Limited cropland, climate change, loss of soil quality and biodiversity coupled with excessive use of non-renewable resources require new solutions for future cropping systems beyond existing management practices. Here we compare the yield performance of organic and conventional cropping systems

    Critical illness-induced bone loss is related to deficient autophagy and histone hypomethylation

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    BACKGROUND Survivors of critical illness are at increased risk of fractures. This may be due to increased osteoclast formation during critical illness, leading to trabecular bone loss. Such bone loss has also been observed in Paget's disease, and has been related to deficient autophagy. Deficient autophagy has also been documented in vital organs and skeletal muscle of critically ill patients. The objective of this study was to investigate whether deficient autophagy can be linked to critical illness-induced bone loss. METHODS Osteoclasts grown in vitro and their precursor cells isolated from peripheral blood of critically ill patients and from matched healthy volunteers were analysed for the expression of autophagy genes (SQSTM1, Atg3 and Atg7), and proteins (p62, Atg-5, and microtubule-associated protein light chain 3-II (LC3-II)) and for autophagy and epigenetic signalling factors via PCR arrays and were treated with the autophagy inducer rapamycin. The effect of rapamycin was also investigated at the tissue level in an in vivo rabbit model of critical illness. RESULTS Many more osteoclasts formed in vitro from the blood precursor cells isolated from critically ill patients, which accumulated p62, and displayed reduced expression of Atg5, Atg7, and LC3-II compared to healthy controls, suggesting deficient autophagy, whilst addition of rapamycin reduced osteoclast formation. PCR arrays revealed a down-regulation of histone methyltransferases coupled with an up-regulation of negative regulators of autophagy. Critically ill rabbits displayed a reduction in trabecular and cortical bone, which was rescued with rapamycin. CONCLUSIONS Deficient autophagy in osteoclasts and their blood precursor cells at least partially explained aberrant osteoclast formation during critical illness and was linked to global histone hypomethylation. Treatment with the autophagy activator Rapamycin reduced patient osteoclast formation in vitro and reduced the amount of bone loss in critically ill rabbits in vivo. These findings may help to develop novel therapeutic targets to prevent critical illness-induced bone loss

    Method For Making 2-Electron Response Reduced Density Matrices Approximately N-representable

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    In methods like geminal-based approaches or coupled cluster that are solved using the projected Schr\"odinger equation, direct computation of the 2-electron reduced density matrix (2-RDM) is impractical and one falls back to a 2-RDM based on response theory. However, the 2-RDMs from response theory are not NN-representable. That is, the response 2-RDM does not correspond to an actual physical NN-electron wave function. We present a new algorithm for making these non-NN-representable 2-RDMs approximately NN-representable, i.e. it has the right symmetry and normalization and it fulfills the PP-, QQ- and GG-conditions. Next to an algorithm which can be applied to any 2-RDM, we have also developed a 2-RDM optimization procedure specifically for seniority-zero 2-RDMs. We aim to find the 2-RDM with the right properties that is the closest (in the sense of the Frobenius norm) to the non-N-representable 2-RDM by minimizing the square norm of the difference between the initial 2-RDM and the targeted 2-RDM under the constraint that the trace is normalized and the 2-RDM, QQ- and GG-matrices are positive semidefinite, i.e. their eigenvalues are non-negative. Our method is suitable for fixing non-N-respresentable 2-RDMs which are close to being N-representable. Through the N-representability optimization algorithm we add a small correction to the initial 2-RDM such that it fulfills the most important N-representability conditions.Comment: 13 pages, 8 figure

    Growth references for height, weight and body mass index of twins aged 0–2.5 years.

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    Aim: To determine the size of the growth deficit in Dutch monozygotic and dizygotic twins aged 0-2.5 years as compared to singletons and to construct reference growth charts for twins. Methods: Growth of twins was studied using longitudinal data on over 4000 twins aged 0-2.5 years of the Netherlands Twin Register. The LMS method was used to obtain growth references for length/height, weight, and body mass index (BMI) for twins. Results: During the first 2.5 years of age, differences in length/height and weight between twins and singletons decrease but do not disappear. BMI of twins deviates less than that of singletons. Approximately half of the growth retardation from birth until 1.5 years of age was attributable to gestational age. Between 1.5 years and 2.5 years of age, this difference was reduced to one-third. Thus, a substantial part of the growth difference could not be explained by gestational age. © 2008 Foundation Acta Pædiatrica

    Healthcare access for refugees in Greece: Challenges and opportunities

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    The arrival of more than one million refugees and migrants in Europe in 2015, most of whom transited through Greece, has placed significant strains on local health systems and demonstrated the need for preparedness to meet the immediate and longer-term health needs of arrivals in EU countries. Population movements will continue to occur and the need for cost effective, appropriate provision of both primary and secondary health services to meet these needs is key. The Global Compact on Migration was ratified in 2018 and forms an overarching, international agreement to address safe, orderly and regular migration which benefits refugees and migrants as well as host communities; however, it did not give due emphasis to health. In this manuscript, we explore the evolution of the health response for refugees in Greece over the last three years, the challenges faced at different times of the response and the efforts to integrate refugees into Greece’s health system

    Use of continuous positive airway pressure reduces airway reactivity in adults with asthma

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    Asthma is characterised by airway hyperreactivity, which is primarily treated with β-adrenergic bronchodilators and anti-inflammatory agents. However, mechanical strain during breathing is an important modulator of airway responsiveness and we have previously demonstrated in animal models that continuous positive airway pressure (CPAP) resulted in lower in vivo airway reactivity. We now evaluated whether using nocturnal CPAP decreased airway reactivity in clinically-stable adults with asthma. Adults with stable asthma and normal spirometry used nocturnal CPAP (8-10 cmH(2)O) or sham treatment (0-2 cmH(2)O) for 7 days. Spirometry and bronchial challenges were obtained before and after treatment. The primary outcome was the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC(20)). The CPAP group (n=16) had a significant decrease in airway reactivity (change in (Δ)logPC(20) 0.406, p<0.0017) while the sham group (n=9) had no significant change in airway reactivity (ΔlogPC(20) 0.003, p=0.9850). There was a significant difference in the change in airway reactivity for the CPAP versus the sham group (ΔlogPC(20) 0.41, p<0.043). Our findings indicate that chronic mechanical strain of the lungs produced using nocturnal CPAP for 7 days reduced airway reactivity in clinically stable asthmatics. Future studies of longer duration are required to determine whether CPAP can also decrease asthma symptoms and/or medication usage

    Effect of CPAP on airway reactivity and airway inflammation in children with moderate-severe asthma

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    BACKGROUND AND OBJECTIVE: Asthma is characterized by airway hyperreactivity and airway inflammation. We previously demonstrated that adults with mild well-controlled asthma exhibited a marked decrease in airway reactivity (PC20 increased >2-fold) after using nocturnal continuous positive airway pressure (CPAP) for 1 week. If CPAP produces a similar suppression of airway reactivity in children with moderate-severe asthma, who require chronic use of corticosteroids, then this non-pharmacological therapy might provide a beneficial alternative or supplemental therapy in these subjects. METHODS: Children aged 8-17 years with moderate-severe asthma were treated with 4 weeks of nocturnal CPAP (8-10 cm H2 O) or sham CPAP (<2 cm H2 O). Adherence was monitored with a modem installed in the equipment or by memory cards. Airway reactivity, assessed by methacholine bronchial challenge, was measured prior to and following treatment. RESULTS: The percentage of subjects adherent to treatment was similar in both groups (19/27 CPAP vs 19/28 sham, ~70%). There was a tendency for PC20 to increase with treatment in both groups (3.0-5.3 mg/mL CPAP vs 3.2 to 4.3 mg/mL sham, P = 0.083); however, the change did not differ significantly between groups (P = 0.569). CONCLUSION: We found that the 4-week treatment with nocturnal CPAP did not produce a twofold suppression of airway reactivity in children with moderate-severe asthma

    Regulation of 130kDa smooth muscle myosin light chain kinase expression by an intronic CArG element

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    The mylk1 gene encodes a 220-kDa nonmuscle myosin light chain kinase (MLCK), a 130-kDa smooth muscle MLCK (smMLCK), as well as the non-catalytic product telokin. Together, these proteins play critical roles in regulating smooth muscle contractility. Changes in their expression are associated with many pathological conditions; thus, it is important to understand the mechanisms regulating expression of mylk1 gene transcripts. Previously, we reported a highly conserved CArG box, which binds serum response factor, in intron 15 of mylk1. Because this CArG element is near the promoter that drives transcription of the 130-kDa smMLCK, we examined its role in regulating expression of this transcript. Results show that deletion of the intronic CArG region from a β-galactosidase reporter gene abolished transgene expression in mice in vivo. Deletion of the CArG region from the endogenous mylk1 gene, specifically in smooth muscle cells, decreased expression of the 130-kDa smMLCK by 40% without affecting expression of the 220-kDa MLCK or telokin. This reduction in 130-kDa smMLCK expression resulted in decreased phosphorylation of myosin light chains, attenuated smooth muscle contractility, and a 24% decrease in small intestine length that was associated with a significant reduction of Ki67-positive smooth muscle cells. Overall, these data show that the CArG element in intron 15 of the mylk1 gene is necessary for maximal expression of the 130-kDa smMLCK and that the 130-kDa smMLCK isoform is specifically required to regulate smooth muscle contractility and small intestine smooth muscle cell proliferation

    A high-powered replication study finds no effect of starting or stopping hormonal contraceptive use on relationship quality

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    A number of recent studies have implicated that incongruent use of hormonal contraceptives (HCs) negatively affects various aspects of women’s romantic relationships. It has been suggested that women with incongruent HC use (a discrepancy in HC use status between when they first met their current partner and the time of study participation) report less sexual satisfaction and higher jealousy scores compared to women with congruent HC use. A similar effect has also been hypothesized for general relationship satisfaction, and recent findings suggest that the association between HC incongruency and general relationship satisfaction is moderated by women’s perceived facial attractiveness of male partners. Using a large convenience sample (N = 948) of Finnish women, we attempted to replicate previously reported findings but found no support for the HC congruency hypothesis, despite excellent statistical power (≥98.7%) to detect previously reported effect sizes. Instead, after dividing our sample into four groups based on HC congruency/incongruency, we found that the largest differences in jealousy, sexual satisfaction, and relationship satisfaction scores tended to be found between women who were consistent HC users and consistent non-users (i.e., between women with different kinds of congruent HC use). We also detected a significant main effect of current HC use on jealousy. We conclude that, as the effect size of the HC incongruency effect reported in previous studies was small, unequal distributions of current HC users within congruent and incongruent HC user groups may give rise to spurious HC incongruency effects in studies using small samples
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