392 research outputs found

    Configurational entropy of network-forming materials

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    We present a computationally efficient method to calculate the configurational entropy of network-forming materials. The method requires only the atomic coordinates and bonds of a single well-relaxed configuration. This is in contrast to the multiple simulations that are required for other methods to determine entropy, such as thermodynamic integration. We use our method to obtain the configurational entropy of well-relaxed networks of amorphous silicon and vitreous silica. For these materials we find configurational entropies of 1.02 kb and 0.97 kb per silicon atom, respectively, with kb the Boltzmann constant.Comment: 4 pages, 4 figure

    The Impact of Silicon Feedstock on the PV Module Cost

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    The impact of the use of new (solar grade) silicon feedstock materials on the manufacturing cost of wafer-based crystalline silicon photovoltaic modules is analyzed considering effects of material cost, efficiency of utilisation, and quality. Calculations based on data provided by European industry partners are presented for a baseline manufacturing technology and for four advanced wafer silicon technologies which may be ready for industrial implementation in the near future. Iso-cost curves show the technology parameter combinations that yield a constant total module cost for varying feedstock cost, silicon utilisation, and cell efficiency. A large variation of feedstock cost for different production processes, from near semiconductor grade Si (30 €/kg) to upgraded metallurgical grade Si (10 €/kg), changes the cost of crystalline silicon modules by 11% for present module technologies or by 7% for advanced technologies, if the cell efficiency can be maintained. However, this cost advantage is completely lost if cell efficiency is reduced, due to quality degradation, by an absolute 1.7% for present module technology or by an absolute 1.3% for advanced technologies

    Shifting Instead of Drifting – Improving Attentional Performance by Means of the Attention Training Technique

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    Background: The Attention Training Technique (ATT) as part of Metacognitive Therapy (MCT) has shown to be a promising treatment element for several psychiatric disorders such as depression and anxiety. ATT predicts improvements of the ability to shift attention away from internal and non-relevant stimuli (e.g., ruminative thoughts) toward the relevant stimuli and aims to increase attentional flexibility and control. The current study investigated the impact of the Attention Training Technique on attentional performance.Methods: Eighty-five healthy participants (29 in two doses ATT, 28 in four doses ATT and 28 in the control group; 18–37 years of age) were administered a test battery for attentional performance before and after an intervention of two doses ATT (23 min duration) vs. four doses of ATT (46 min duration) vs. a control condition (non-intervention audio file via headphones. The test battery measured selective attention, inhibition, working memory, and attentional disengagement and comprised the following tasks: dichotic listening, attentional bias, attentional network, stroop, 2-back and a 3-back.Results: After ATT (both two and four doses), reaction time during dichotic listening was significantly faster compared to the control condition. Furthermore, reaction time to neutral stimuli in the attentional bias task was faster after four-doses ATT compared to two doses ATT and the control condition. We found a trend toward a reduced stroop effect for both ATT conditions compared to control group. There were no effects of ATT with regard to the attentional network task, the 2-back or the 3-back task.Conclusion: This first empirical evidence suggests that ATT promotes specific attentional flexibility in healthy participants. Based on the same mechanism, ATT may have beneficial effects on attentional performance in clinical populations and might be a promising tool in both healthy and clinical participants

    Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

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    Veldproeven in 1980, 1981 en 1982, waarbij naast de in de titel genoemde effecten tevens de interactie van schimmelflora en graanluizen werd nagegaa

    Spinocerebellar ataxia type 19/22 mutations alter heterocomplex Kv4.3 channel function and gating in a dominant manner

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    The dominantly inherited cerebellar ataxias are a heterogeneous group of neurodegenerative disorders caused by Purkinje cell loss in the cerebellum. Recently, we identified loss-of-function mutations in the KCND3 gene as the cause of spinocerebellar ataxia type 19/22 (SCA19/22), revealing a previously unknown role for the voltage-gated potassium channel, Kv4.3, in Purkinje cell survival. However, how mutant Kv4.3 affects wild-type Kv4.3 channel functioning remains unknown. We provide evidence that SCA19/22-mutant Kv4.3 exerts a dominant negative effect on the trafficking and surface expression of wild-type Kv4.3 in the absence of its regulatory subunit, KChIP2. Notably, this dominant negative effect can be rescued by the presence of KChIP2. We also found that all SCA19/22-mutant subunits either suppress wild-type Kv4.3 current amplitude or alter channel gating in a dominant manner. Our findings suggest that altered Kv4.3 channel localization and/or functioning resulting from SCA19/22 mutations may lead to Purkinje cell loss, neurodegeneration and ataxia

    Implementation of vacuum-assisted excision as a management option for benign and high-risk breast lesions

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    Objective: Previous studies have shown that vacuum-assisted excision (VAE) is a safe and effective alternative for surgical excision (SE) of benign breast lesions. However, the use of VAE in high-risk lesions is controver-sial and guidelines are ambiguous. This study describes the impact of the implementation of VAE in terms of management and outcomes compared to a cohort before implementation. Methods: A single centre retrospective study with two cohorts: ‘before’ and ‘after’ implementation of VAE was performed. All patients with a benign or high-risk lesion treated by VAE or SE between 2016 and 2019 were included. Excision, complication, and upgrade rates were compared between both cohorts. Cox regression was used for the evaluation of recurrences and re-excisions. Results: The overall excision rate of all benign and high-risk lesions was comparable in both cohorts (17% vs 16%, p = 0.700). After implementation, benign lesions were significantly more often managed by VAE (101/151, 67%, p &lt; 0.001). Re-excision, recurrence, and complication rates were low and comparable between cohorts (4.3% vs 3.9%, p &gt; 0.999; 3.0 vs 2.0%, p = 0.683; 3.4 vs 6.6%, p = 0.289, respectively). Conclusion: SE could safely be replaced by VAE in 58% of patients treated for a benign or high-risk lesion. With this shift in management, the use of operating rooms and general anaesthesia can safely be omitted in this patient group. Further research on high-risk lesions is warranted since our data are exploratory. Advances in knowledge: This study provides supportive data for the use of VAE as a management option for both benign (up to 5 cm) and high-risk lesions. Outcomes on re-excision, recurrence should be confirmed in prospective studies especially in high-risk lesions.</p

    Cardiomyopathy in patients with epidermolysis bullosa simplex with mutations in KLHL24

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    Dominant mutations in the KLHL24 gene, encoding for kelch-like protein 24, have been implicated in the pathogenesis of epidermolysis bullosa simplex (EBS). So far, 26 patients from different ethnicities have been reported and all of them harboured a heterozygous KLHL24 start-codon mutation, with c.1A>G;p.Met1? being the most prevalent.1-3 Through this report, we aimed to expand the phenotypic spectrum by incorporating additional findings, in particular, dilated cardiomyopathy, seen in a Dutch family. This article is protected by copyright. All rights reserved
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