5,619 research outputs found
A minK-HERG complex regulates the cardiac potassium current I(Kr).
MinK is a widely expressed protein of relative molecular mass approximately 15K that forms potassium channels by aggregation with other membrane proteins. MinK governs ion channel activation, regulation by second messengers, and the function and structure of the ion conduction pathway. Association of minK with a channel protein known as KvLQT1 produces a voltage-gated outward K+ current (I[sK]) resembling the slow cardiac repolarization current (I[Ks]). HERG, a human homologue of the ether-a-go-go gene of the fruitfly Drosophila melanogaster, encodes a protein that produces the rapidly activating cardiac delayed rectifier (I[Kr]). These two potassium currents, I(Ks) and I(Kr), provide the principal repolarizing currents in cardiac myocytes for the termination of action potentials. Although heterologously expressed HERG channels are largely indistinguishable from native cardiac I(Kr), a role for minK in this current is suggested by the diminished I(Kr) in an atrial tumour line subjected to minK antisense suppression. Here we show that HERG and minK form a stable complex, and that this heteromultimerization regulates I(Kr) activity. MinK, through the formation of heteromeric channel complexes, is thus central to the control of the heart rate and rhythm
Impacts of Co-Solvent Flushing on Microbial Populations Capable of Degrading Trichloroethylene
With increased application of co-solvent flushing technologies for removal of nonaqueous phase liquids from groundwater aquifers, concern over the effects of the solvent on native microorganisms and their ability to degrade residual contaminant has also arisen. This study assessed the impact of ethanol flushing on the numbers and activity potentials of trichloroethylene (TCE)-degrading microbial populations present in aquifer soils taken immediately after and 2 years after ethanol flushing of a former dry cleaners site. Polymerase chain reaction analysis revealed soluble methane monooxygenase genes in methanotrophic enrichments, and 16S rRNA analysis identified Methylocystis parvus with 98% similarity, further indicating the presence of a type II methanotroph. Dissimilatory sulfite reductase genes in sulfate-reducing enrichments prepared were also observed. Ethanol flushing was simulated in columns packed with uncontaminated soils from the dry cleaners site that were dosed with TCE at concentrations observed in the field; after flushing, the columns were subjected to a continuous flow of 500 pore volumes of groundwater per week. Total acridine orange direct cell counts of the flushed and nonflushed soils decreased over the 15-week testing period, but after 5 weeks, the flushed soils maintained higher cell counts than the nonflushed soils. Inhibition of methanogenesis by sulfate reduction was observed in all column soils, as was increasing removal of total methane by soils incubated under methanotrophic conditions. These results showed that impacts of ethanol were not as severe as anticipated and imply that ethanol may mitigate the toxicity of TCE to the microorganisms
Embedding Node Structural Role Identity into Hyperbolic Space
Recently, there has been an interest in embedding networks in hyperbolic
space, since hyperbolic space has been shown to work well in capturing
graph/network structure as it can naturally reflect some properties of complex
networks. However, the work on network embedding in hyperbolic space has been
focused on microscopic node embedding. In this work, we are the first to
present a framework to embed the structural roles of nodes into hyperbolic
space. Our framework extends struct2vec, a well-known structural role
preserving embedding method, by moving it to a hyperboloid model. We evaluated
our method on four real-world and one synthetic network. Our results show that
hyperbolic space is more effective than euclidean space in learning latent
representations for the structural role of nodes.Comment: In Proceedings of the 29th ACM International Conference on
Information and Knowledge Management (CIKM '20), October 19-23, 2020, Virtual
Event, Irelan
Effect of Ni on the Formation and Growth of Primary Cu6Sn5 Intermetallics in Sn-0.7 wt.%Cu Solder Pastes on Cu Substrates During the Soldering Process
This paper investigates the effect of 0.05 wt.% Ni on the formation and growth of primary Cu6Sn5 in Sn-0.7 wt.%Cu solder paste soldered on a Cu substrate, using a real-time synchrotron imaging technique. It was found that small additions of Ni significantly alter the formation and growth of the primary Cu6Sn5 intermetallics, making them small. In contrast, without Ni, primary Cu6Sn5 intermetallics tend to continue growth throughout solidification and end up much larger and coarser. The primary effect of the Ni addition appears to be in promoting the nucleation of a larger amount of small Cu6Sn5. The results provide direct evidence of the sequence of events in the reaction of Ni-containing Sn-0.7 wt.%Cu solder paste with a Cu substrate, and in particular the formation and growth of the primary Cu6Sn5 intermetallic
Projections of the healthcare costs and disease burden due to hepatitis C infection under different treatment policies in Malaysia, 2018-2040
The World Health Organisation (WHO) has set ambitious goals to reduce the global disease burden associated with, and eventually eliminate, viral hepatitis
Care Burden and Mental Ill Health in Spouses of People With Parkinson Disease Dementia and Lewy Body Dementia
This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record. Objectives: To explore and compare levels of mental health, care burden, and relationship satisfaction among caregiving spouses of people with mild cognitive impairment or dementia in Parkinson disease (PD-MCI or PDD) or dementia with Lewy bodies (DLB). Methods: Spouses (n = 136) completed measures of mood, stress, resilience, general health, quality of life, care burden, and relationship satisfaction, as well as sociodemographic factors. Additionally, data on motor and neuropsychiatric symptom severity of people with PD-MCI, PDD, or DLB were obtained in a subsample. Results: Most spouses were married women (>85%) who provided a median of 4 years of care and 84 hours of weekly care. Among these, relationship dissatisfaction, stress, anxiety, care burden, and feelings of resentment were common. Spouses of people with PDD and DLB had significantly higher rates of burden, resentment, and depression compared to spouses of people with PD-MCI. Furthermore, unique group differences emerged whereby spouses of people with PDD had significantly longer duration of care provision, higher stress, more relationship dissatisfaction, and fewer positive interactions, compared to PD-MCI group, whereas anxiety and lower levels of mental health were prominent in spouses of people with DLB, compared to PD-MCI group. Despite this, the majority of spouses reported good quality of life, resilience, and satisfaction with the caring role. Conclusion: Both PDD and DLB significantly contribute to poorer mental health and higher levels of care burden in spouses. Clinicians should actively screen the risk of burden, stress, depression, and anxiety among caregiving spouses of people with these conditions.National Institute for Health Research (NIHR
Drugs-related death soon after hospital discharge among drug treatment clients in Scotland:record linkage, validation and investigation of risk factors.
We validate that the 28 days after hospital-discharge are high-risk for drugs-related death (DRD) among drug users in Scotland and investigate key risk-factors for DRDs soon after hospital-discharge. Using data from an anonymous linkage of hospitalisation and death records to the Scottish Drugs Misuse Database (SDMD), including over 98,000 individuals registered for drug treatment during 1 April 1996 to 31 March 2010 with 705,538 person-years, 173,107 hospital-stays, and 2,523 DRDs. Time-at-risk of DRD was categorised as: during hospitalization, within 28 days, 29-90 days, 91 days-1 year, >1 year since most recent hospital discharge versus 'never admitted'. Factors of interest were: having ever injected, misuse of alcohol, length of hospital-stay (0-1 versus 2+ days), and main discharge-diagnosis. We confirm SDMD clients' high DRD-rate soon after hospital-discharge in 2006-2010. DRD-rate in the 28 days after hospital-discharge did not vary by length of hospital-stay but was significantly higher for clients who had ever-injected versus otherwise. Three leading discharge-diagnoses accounted for only 150/290 DRDs in the 28 days after hospital-discharge, but ever-injectors for 222/290. Hospital-discharge remains a period of increased DRD-vulnerability in 2006-2010, as in 1996-2006, especially for those with a history of injecting
Psychosocial therapy for Parkinson's-related dementia: intervention development.
Background: Group-based psychosocial therapy, such as group Cognitive Stimulation Therapy, improves cognition and quality of life in people living with dementia. Neuropsychiatric symptoms and restricted mobility are common complications for people with Parkinson's-related dementia (PRD) and may limit access to, and participation in, group activities. This study describes the development of a condition-specific, home-based psychosocial therapy for people with PRD ready to be trialled in a clinical population. Methods: By means of a multistage process, a draft therapy manual was developed in an iterative manner through collaboration with medical experts, researchers and Patient and Public Involvement (PPI) representatives. In stage 1, an extensive literature search of psychosocial therapies for dementia with potential relevance for Parkinson's disease (PD) was undertaken to select a candidate therapy for adaptation. In stage 2, qualitative feedback from stakeholders and intelligence regarding existing nonpharmacological therapies for cognitive impairment in PD was combined to produce a prototype therapy manual. In stage 3, the manual was field tested in: 1) a home-setting using a 25-item assessment tool; and 2) at a local PD support group with PPI representatives. Based on the feedback from this phase, final design modifications were implemented and a draft therapy manual produced. Results: The manual was developed in an iterative manner. Interview and focus group transcripts identified three enduring themes: manual form and content, therapy acceptability by people with PRD, and companion guidance and support. Major adaptations included: removal of discrete levels of task complexity, removal of images that were potentially hallucinogenic or lacked clarity, and updating of the content. Conclusion: We have successfully developed a Cognitive Stimulation Therapy-based psychosocial therapy specifically adapted for people with PRD. The therapy is ready to trial in a pilot randomized controlled study
Projections of the current and future disease burden of hepatitis C virus infection in Malaysia
The prevalence of hepatitis C virus (HCV) infection in Malaysia has been estimated at 2.5% of the adult population. Our objective, satisfying one of the directives of the WHO Framework for Global Action on Viral Hepatitis, was to forecast the HCV disease burden in Malaysia using modelling methods.An age-structured multi-state Markov model was developed to simulate the natural history of HCV infection. We tested three historical incidence scenarios that would give rise to the estimated prevalence in 2009, and calculated the incidence of cirrhosis, end-stage liver disease, and death, and disability-adjusted life-years (DALYs) under each scenario, to the year 2039. In the baseline scenario, current antiviral treatment levels were extended from 2014 to the end of the simulation period. To estimate the disease burden averted under current sustained virological response rates and treatment levels, the baseline scenario was compared to a counterfactual scenario in which no past or future treatment is assumed.In the baseline scenario, the projected disease burden for the year 2039 is 94,900 DALYs/year (95% credible interval (CrI): 77,100 to 124,500), with 2,002 (95% CrI: 1340 to 3040) and 540 (95% CrI: 251 to 1,030) individuals predicted to develop decompensated cirrhosis and hepatocellular carcinoma, respectively, in that year. Although current treatment practice is estimated to avert a cumulative total of 2,200 deaths from DC or HCC, a cumulative total of 63,900 HCV-related deaths is projected by 2039.The HCV-related disease burden is already high and is forecast to rise steeply over the coming decades under current levels of antiviral treatment. Increased governmental resources to improve HCV screening and treatment rates and to reduce transmission are essential to address the high projected HCV disease burden in Malaysia
Permeability and acoustic velocity controlling factors determined from x-ray tomography images of carbonate rocks
Carbonate reservoir rocks exhibit a great variability in texture that directly impacts petrophysical parameters. Many exhibit bi- and multimodal pore networks, with pores ranging from less than 1 μm to several millimeters in diameter. Furthermore, many pore systems are too large to be captured by routine core analysis, and well logs average total porosity over different volumes. Consequently, prediction of carbonate properties from seismic data and log interpretation is still a challenge. In particular, amplitude versus offset classification systems developed for clastic rocks, which are dominated by connected, intergranular, unimodal pore networks, are not applicable to carbonate rocks. Pore geometrical parameters derived from digital image analysis (DIA) of thin sections were recently used to improve the coefficient of determination of velocity and permeability versus porosity. Although this substantially improved the coefficient of determination, no spatial information of the pore space was considered, because DIA parameters were obtained from two-dimensional analyses. Here, we propose a methodology to link local and global pore-space parameters, obtained from three-dimensional (3-D) images, to experimental physical properties of carbonate rocks to improve P-wave velocity and permeability predictions. Results show that applying a combination of porosity, microporosity, and 3-D geometrical parameters to P-wave velocity significantly improves the adjusted coefficient of determination from 0.490 to 0.962. A substantial improvement is also observed in permeability prediction (from 0.668 to 0.948). Both results can be interpreted to reflect a pore geometrical control and pore size control on P-wave velocity and permeability
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