750 research outputs found
Nuclear quantum effects in water exchange around lithium and fluoride ions
We employ classical and ring polymer molecular dynamics simulations to study
the effect of nuclear quantum fluctuations on the structure and the water
exchange dynamics of aqueous solutions of lithium and fluoride ions. While we
obtain reasonably good agreement with experimental data for solutions of
lithium by augmenting the Coulombic interactions between the ion and the water
molecules with a standard Lennard-Jones ion-oxygen potential, the same is not
true for solutions of fluoride, for which we find that a potential with a
softer repulsive wall gives much better agreement. A small degree of
destabilization of the first hydration shell is found in quantum simulations of
both ions when compared with classical simulations, with the shell becoming
less sharply defined and the mean residence time of the water molecules in the
shell decreasing. In line with these modest differences, we find that the
mechanisms of the exchange processes are unaffected by quantization, so a
classical description of these reactions gives qualitatively correct and
quantitatively reasonable results. We also find that the quantum effects in
solutions of lithium are larger than in solutions of fluoride. This is partly
due to the stronger interaction of lithium with water molecules, partly due to
the lighter mass of lithium, and partly due to competing quantum effects in the
hydration of fluoride, which are absent in the hydration of lithium.Comment: 12 pages, 8 figure
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Impacts of Exhaust Transfer System Contamination on Particulate Matter Measurements
The Process of Entrepreneurship Learning on Innovative Venture Creation at University of Ciputra, Surabaya
The purpose of this paper is to know innovation learning result of Entrepreneurship 4: Innovation Venture Creation through Business Model Canvas. Five learning sequences within entrepreneurship 4, searching opportunity, generated solution ideas, market testing, business model analysis; and implementation and evaluation of students' innovative venture in products or services or/and innovative business model. As an action research, this paper has been created based on case study of 407 students in multidisciplinary. This paper will focus on continuous learning process in order to create an innovative venture. The result of this learning process is 97 real business units that divided into five categories: food and beverage, fashion, IT and graphic design, interior and animal. The final result is 9% of the business units managed to reach break-even point within 6 weeks, while 59% of the total business unit had gained financial profit
Mechanistic and therapeutic aspects of ischemic myocardial preconditioning
To obtain a better understanding of myocardial ischemia-reperfusion injury and to
advance therapeutical application of cardiac adaptation to ischemia, this thesis investigates
several mechanistic aspects of ischemic preconditioning with respect to triggers, mediators and
possible end-effectors.
Adenosine is a well established trigger of ischemic preconditioning which is released
during ischemia as a breakdown product of ATP. At least four adenosine receptor subtypes
have been identified: A1-, A2a-, A2b- and A3- receptors.221 Both the A1- and the A3- receptor
subtypes are believed to trigger myocardial preconditioning.131·153·222 The cardioprotective role
of adenosine has been confirmed in all species used for experimental investigation.38 However,
based on several studies using selective adenosine receptor antagonists which failed to block
ischemic preconditioning, its role in rats is still controversial. 155•156 In these studies the duration
of the ischemic stimuli were 3-5 min. Interestingly, Schulz et al. 133 demonstrated in the porcine
heart that adenosine plays a significant role after 10-min of coronary artery occlusion.
Therefore in chapter 2 we studied the role of adenosine in ischemic preconditioning in rats
with respect to the duration of the ischemic stimulu
Perceptions and Experiences of Perinatal Mental Disorders in Rural, Predominantly Ethnic Minority Communities in Northern Vietnam
Background: Preliminary research has suggested that perinatal mental disorders (PMDs), including post-partum depression, are prevalent in Vietnam. However the extent to which these disorders are recognized at the community level remains largely undocumented in the literature. PMDs have also never been investigated within Vietnam’s significant ethnic minority populations, who are known to bear a greater burden of maternal and infant health challenges than the ethnic majority. Objective: To investigate knowledge and perceptions of PMDs and their treatments at the community level in a rural, predominantly ethnic minority region of northern Vietnam
Read/Write Digital Libraries for Musicology
The Web and other digital technologies have democratised music creation, reception, and analysis, putting music in the hands, ears, and minds of billions of users. Music digital libraries typically focus on an essential subset of this deluge—commercial and academic publications, and historical materials—but neglect to incorporate contributions by scholars, performers, and enthusiasts, such as annotations or performed interpretations of these artifacts, despite their potential utility for many types of users.
In this paper we consider means by which digital libraries for musicology may incorporate such contributions into their collections, adhering to principles of FAIR data management and respecting contributor rights as outlined in the EU’s General Data Protection Regulation. We present an overview of centralised and decentralised approaches to this problem, and propose hybrid solutions in which contributions reside in a) user-controlled personal online datastores, b) decentralised file storage, and c) are published and aggregated into digital library collections. We outline the implementation of these ideas using Solid, a Web decentralisation project building on W3C standard technologies to facilitate publication and control over Linked Data. We demonstrate the feasibility of this approach by implementing prototypes supporting two types of contribution: Web Annotations describing or analysing musical elements in score encodings and music recordings; and, music performances and associated metadata supporting performance analyses across many renditions of a given piece. Finally, we situate these ideas within a wider conception of enriched, decentralised, and interconnected online music repositories
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Flow-Responsive Vascular Endothelial Growth Factor Receptor-Protein Kinase C Isoform Epsilon Signaling Mediates Glycolytic Metabolites for Vascular Repair
Aims: Hemodynamic shear stress participates in maintaining vascular redox status. Elucidating flow-mediated endothelial metabolites enables us to discover metabolic biomarkers and therapeutic targets. We posited that flow-responsive vascular endothelial growth factor receptor (VEGFR)-protein kinase C isoform epsilon (PKCÉ›)-6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) signaling modulates glycolytic metabolites for vascular repair.
Results: Bidirectional oscillatory flow (oscillatory shear stress [OSS]: 0.1 ± 3 dyne·cm^(−2) at 1 Hz) upregulated VEGFR-dependent PKCɛ expression to a greater degree than did unidirectional pulsatile flow (pulsatile shear stress [PSS]: 23 ± 8 dyne·cm^(−2) at 1 Hz) in human aortic endothelial cells (p < 0.05, n = 3). PSS and OSS further upregulated PKCɛ-dependent PFKFB3 expression for glycolysis (p < 0.05, n = 4). Constitutively active PKCɛ increased, whereas dominant-negative PKCɛ reduced both basal and maximal extracellular acidification rates for glycolytic flux (p < 0.01, n = 4). Metabolomic analysis demonstrated an increase in PKCɛ-dependent glycolytic metabolite, dihydroxyacetone (DHA), but a decrease in gluconeogenic metabolite, aspartic acid (p < 0.05 vs. control, n = 6). In a New Zealand White rabbit model, both PKCɛ and PFKFB3 immunostaining was prominent in the PSS- and OSS-exposed aortic arch and descending aorta. In a transgenic Tg(flk-1:EGFP) zebrafish model, GATA-1a morpholino oligonucleotide injection (to reduce viscosity-dependent shear stress) impaired vascular regeneration after tail amputation (p < 0.01, n = 20), which was restored with PKCɛ messenger RNA (mRNA) rescue (p < 0.05, n = 5). As a corollary, siPKCɛ inhibited tube formation and vascular repair, which were restored by DHA treatment in our Matrigel and zebrafish models.
Innovation and Conclusion: Flow-sensitive VEGFR-PKCÉ›-PFKFB3 signaling increases the glycolytic metabolite, dihydroxyacetone, to promote vascular repair
Divergent Mitochondrial Biogenesis Responses in Human Cardiomyopathy
Background—Mitochondria are key players in the development and progression of heart failure (HF). Mitochondrial (mt) dysfunction leads to diminished energy production and increased cell death contributing to the progression of left ventricular failure. The fundamental mechanisms that underlie mt dysfunction in HF have not been fully elucidated.
Methods and Results—To characterize mt morphology, biogenesis, and genomic integrity in human HF, we investigated left ventricular tissue from nonfailing hearts and end-stage ischemic (ICM) or dilated (DCM) cardiomyopathic hearts. Although mt dysfunction was present in both types of cardiomyopathy, mt were smaller and increased in number in DCM compared with ICM or nonfailing hearts. mt volume density and mtDNA copy number was increased by ≈2-fold (P<0.001) in DCM hearts in comparison with ICM hearts. These changes were accompanied by an increase in the expression of mtDNA-encoded genes in DCM versus no change in ICM. mtDNA repair and antioxidant genes were reduced in failing hearts, suggestive of a defective repair and protection system, which may account for the 4.1-fold increase in mtDNA deletion mutations in DCM (P<0.05 versus nonfailing hearts, P<0.05 versus ICM).
Conclusions—In DCM, mt dysfunction is associated with mtDNA damage and deletions, which could be a consequence of mutating stress coupled with a peroxisome proliferator-activated receptor γ coactivator 1α–dependent stimulus for mt biogenesis. However, this maladaptive compensatory response contributes to additional oxidative damage. Thus, our findings support further investigations into novel mechanisms and therapeutic strategies for mt dysfunction in DCM
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