334 research outputs found

    A critical comparison of approaches to resource name management within the IEC common information model

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    Copyright @ 2012 IEEEElectricity network resources are frequently identified within different power systems by inhomogeneous names and identities due to the legacy of their administration by different utility business domains. The IEC 61970 Common Information Model (CIM) enables network modeling to reflect the reality of multiple names for unique network resources. However this issue presents a serious challenge to the integrity of a shared CIM repository that has the task of maintaining a resource manifest, linking network resources to master identities, when unique network resources may have multiple names and identities derived from different power system models and other power system applications. The current approach, using CIM 15, is to manage multiple resource names within a singular CIM namespace utilizing the CIM “IdentifiedObject” and “Name” classes. We compare this approach to one using additional namespaces relating to different power systems, similar to the practice used in CIM extensions, in order to more clearly identify the genealogy of a network resource, provide faster model import times and a simpler means of supporting the relationship between multiple resource names and identities and a master resource identity.This study is supported by the UK National Grid and Brunel University

    Low frequency sound propagation in activated carbon

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    Activated carbon can adsorb and desorb gas molecules onto and off its surface. Research has examined whether this sorption affects low frequency sound waves, with pressures typical of audible sound, interacting with granular activated carbon. Impedance tube measurements were undertaken examining the resonant frequencies of Helmholtz resonators with different backing materials. It was found that the addition of activated carbon increased the compliance of the backing volume. The effect was observed up to the highest frequency measured (500 Hz), but was most significant at lower frequencies (at higher frequencies another phenomenon can explain the behavior). An apparatus was constructed to measure the effective porosity of the activated carbon as well as the number of moles adsorbed at sound pressures between 104 and 118 dB and low frequencies between 20 and 55 Hz. Whilst the results were consistent with adsorption affecting sound propagation, other phenomena cannot be ruled out. Measurements of sorption isotherms showed that additional energy losses can be caused by water vapor condensing onto and then evaporating from the surface of the material. However, the excess absorption measured for low frequency sound waves is primarily caused by decreases in surface reactance rather than changes in surface resistance

    Molecular basis of neurocognitive dysfunction and psychosis in Alpha-Mannosidosis

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    A significant portion of patients who are afflicted with lysosomal storage diseases (LSDs) encounter neurological manifestations, including cognitive issues and developmental delay, seizures, psychiatric issues, and an overall neurodegenerative decline. In order to enhance the development of effective therapies for these symptoms, it is imperative that we allude to the neuropathophysiology that underlies these manifestations. These distinct neurological and developmental features are particularly evident in patients with Alpha-Mannosidosis (AM), a type of LSD. However, there is limited published information regarding the mechanisms and pathophysiology of these presentations in patients with this condition. Although the precise impact of lysosomal storage on the biogenesis and functioning of neuronal cells has not been clearly defined, recent studies have placed emphasis on the significance of synaptic defects influencing this dysfunction. These defects encompass changes in synaptic spines, proteins, and vesicles, as well as postsynaptic densities that potentially precipitate functional disruptions in synaptic transmission and neurodegeneration. Ultimately, this cascade is thought to result in extensive neuronal loss and, consequently, the onset of cognitive manifestations. Uncovering the effects on synaptic components in LSDs with neurological symptoms like AM will enable a better understanding of disease progression. It will also allow us to identify critical targets for therapeutic intervention and the determination of optimal time frames for targeted treatments, as well as the effects of these treatments on mitochondrial function. The available therapeutic modalities in AM are not a definitive cure for affected patients, but rather an attempt to reduce the symptomatic severity in their presentation, while aiming to regress/slow down disease progression. This review will aim to discuss and rationalize the current treatment approaches in place for AM patients in relation to their effects on the improvement of neurocognitive symptoms in affected AM individuals

    Mitochondria and Quality Control Defects in a Mouse Model of Gaucher Disease-Links to Parkinson's Disease

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    Mutations in the glucocerebrosidase (gba) gene cause Gaucher disease (GD), the most common lysosomal storage disorder, and increase susceptibility to Parkinson’s disease (PD). While the clinical and pathological features of idiopathic PD and PD related to gba (PD-GBA) mutations are very similar, cellular mechanisms underlying neurodegeneration in each are unclear. Using a mouse model of neuronopathic GD, we show that autophagic machinery and proteasomal machinery are defective in neurons and astrocytes lacking gba. Markers of neurodegeneration—p62/SQSTM1, ubiquitinated proteins, and insoluble α-synuclein—accumulate. Mitochondria were dysfunctional and fragmented, with impaired respiration, reduced respiratory chain complex activities, and a decreased potential maintained by reversal of the ATP synthase. Thus a primary lysosomal defect causes accumulation of dysfunctional mitochondria as a result of impaired autophagy and dysfunctional proteasomal pathways. These data provide conclusive evidence for mitochondrial dysfunction in GD and provide insight into the pathogenesis of PD and PD-GBA

    Do Quality Improvement Initiatives Improve Outcomes for Patients in Antiretroviral Programs in Low- and Middle-Income Countries? A Systematic Review.

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    BACKGROUND: There have been a range of quality improvement (QI) and quality assurance initiatives in low- and middle-income countries to improve antiretroviral therapy (ART) treatment outcomes for people living with HIV. To date, these initiatives have not been systematically assessed and little is known about how effective, cost-effective, or sustainable these strategies are in improving clinical outcomes. METHODS: We conducted a systematic review adhering to PRISMA guidelines (PROSPERO ID: CRD42017071848), searching PubMed, MEDLINE, Embase, Web of Science, and the Cochrane database of controlled trials for articles reporting on the effectiveness of QI and quality assurance initiatives in HIV programs in low- and middle-income countries in relation to ART uptake, retention in care, adherence, viral load suppression, mortality, and other outcomes including cost-effectiveness and long-term sustainability. RESULTS: One thousand eight hundred sixty articles were found, of which 29 were included. QI approaches were categorized as follows: (1) health system approaches using QI methods; (2) QI learning networks including collaboratives; (3) standard-based methods that use QI tools to improve performance gaps; and (4) campaigns using QI methods. The greatest improvements were seen in ART uptake [median increase of 14.0%; interquartile range (IQR) -9.0 to 29.3], adherence [median increase of 22.0% (IQR -7.0 to 25.0)], and viral load suppression [median increase 26.0% (IQR -8.0 to 26.0)]. CONCLUSIONS: QI interventions can be effective in improving clinical outcomes; however, there was significant variability, making it challenging to identify which aspects of interventions lead to clinical improvements. Standardizing reporting and assessment of QI initiatives is needed, supported by national quality policies and directorates, and robust research

    Primary source of income is associated with differences in HIV risk behaviors in street-recruited samples

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    BACKGROUND: The relationship between primary source of income and HIV risk behaviors and the racial/ethnic differences in risk behavior profiles among disadvantaged populations have not been fully explored. This is unusual given that the phenomenon of higher risk in more disadvantaged populations is well-known but the mechanisms remain unclear. We examined the relationship between primary source of income and differences in HIV risk behaviors among four racial/ethnic groups in the southern United States. METHODS: Self-reported data on primary source of income and HIV risk behaviors were collected from 1494 African American, Hispanic, Asian, and White men and women in places of public congregation in Houston, Texas. Data were analyzed using calculation of percentages and by chi-square tests with Yates correction for discontinuity where appropriate. RESULTS: Data revealed that a higher proportion of whites were involved in sex for money exchanges compared to the other racial groups in this sample. The data suggest that similar street sampling approaches are likely to recruit different proportions of people by primary income source and by ethnicity. It may be that the study locations sampled are likely to preferentially attract those involved in illegal activities, specifically the white population involved in sex for drug or money exchanges. Research evidence has shown that people construct highly evolved sexual marketplaces that are localized and most unlikely to cross racial, ethnic, and socioeconomic or geographical boundaries. Thus, the areas that we sampled may have straddled a white sexual marketplace more than that of the other groups, leading to an over-representation of sex exchange in this group. Drug use was highest among those with illegal primary sources of income (sex exchange and drug dealing and theft), and they were also those most likely to have injected drugs rather than administered them by any other route (p < 0.001). In addition, bisexual or homosexual identification was reported by more respondents in the sex exchange as primary source of income category. The number of sexual partners in the last three months followed a similar pattern, with those whose primary source of income was drug dealing or theft reporting relatively high partner numbers. CONCLUSIONS: These data suggest that social disadvantage is associated with HIV risk in part by its association with drug and sex work for survival, and offers one variable that may be associated with the concentration of disease among those at greatest disadvantage by having an illegal and unstable primary income source

    Mitochondrial dysfunction is an important cause of neurological deficits in an inflammatory model of multiple sclerosis

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    Neuroinflammation can cause major neurological dysfunction, without demyelination, in both multiplesclerosis (MS) and a mouse model of the disease (experimental autoimmune encephalomyelitis; EAE), but the mechanisms remain obscure. Confocal in vivo imaging of the mouse EAE spinal cord reveals that impaired neurological function correlates with the depolarisation of both the axonal mitochondria and the axons themselves. Indeed, the depolarisation parallels the expression of neurological deficit at the onset of disease, and during relapse, improving during remission in conjunction with the deficit. Mitochondrial dysfunction, fragmentation and impaired trafficking were most severe in regions of extravasated perivascular inflammatory cells. The dysfunction at disease onset was accompanied by increased expression of the rate-limiting glycolytic enzyme phosphofructokinase-2 in activated astrocytes, and by selective reduction in spinal mitochondrial complex I activity. The metabolic changes preceded any demyelination or axonal degeneration. We conclude that mitochondrial dysfunction is a major cause of reversible neurological deficits in neuroinflammatory disease, such as MS

    Decline in HIV Prevalence among Young Women in Zambia: National-Level Estimates of Trends Mask Geographical and Socio-Demographic Differences

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    Background: A decline in HIV incidence has been reported in Zambia and a number of other sub-Saharan countries. The trend of HIV prevalence among young people is a good marker of HIV incidence. In this study, different data sources are used to examine geographical and sub-population group differentials in HIV prevalence trends among men and women aged 15–24 years in Zambia. Design and Methods: We analysed ANC data for women aged 15–24 years from 22 sentinel sites consistently covered in the period 1994–2008, and HIV data for young men and women aged 15–24 years from the ZDHS 2001/2 and 2007. In addition, we systematically reviewed peer-reviewed articles that have reported findings on HIV prevalence and incidence among young people. Findings: Overall trends of the ANC surveillance data indicated a substantial HIV prevalence decline among young women in both urban and rural areas. However, provincial declines differed substantially, i.e. between 10 % and 68 % among urban women, and from stability to 86 % among rural women. Prevalence declines were steeper among those with the highest educational attainments than among the least educated. The ZDHS data indicated a significant reduction in prevalence between the two survey rounds among young women only. Provincial-level ZDHS changes were difficult to assess because the sample sizes were small. ANC-based trend patterns were consistent with those observed in PMTCT-based data (2002

    Issues in the construction of wealth indices for the measurement of socio-economic position in low-income countries

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    BACKGROUND: Epidemiological studies often require measures of socio-economic position (SEP). The application of principal components analysis (PCA) to data on asset-ownership is one popular approach to household SEP measurement. Proponents suggest that the approach provides a rational method for weighting asset data in a single indicator, captures the most important aspect of SEP for health studies, and is based on data that are readily available and/or simple to collect. However, the use of PCA on asset data may not be the best approach to SEP measurement. There remains concern that this approach can obscure the meaning of the final index and is statistically inappropriate for use with discrete data. In addition, the choice of assets to include and the level of agreement between wealth indices and more conventional measures of SEP such as consumption expenditure remain unclear. We discuss these issues, illustrating our examples with data from the Malawi Integrated Household Survey 2004-5. METHODS: Wealth indices were constructed using the assets on which data are collected within Demographic and Health Surveys. Indices were constructed using five weighting methods: PCA, PCA using dichotomised versions of categorical variables, equal weights, weights equal to the inverse of the proportion of households owning the item, and Multiple Correspondence Analysis. Agreement between indices was assessed. Indices were compared with per capita consumption expenditure, and the difference in agreement assessed when different methods were used to adjust consumption expenditure for household size and composition. RESULTS: All indices demonstrated similarly modest agreement with consumption expenditure. The indices constructed using dichotomised data showed strong agreement with each other, as did the indices constructed using categorical data. Agreement was lower between indices using data coded in different ways. The level of agreement between wealth indices and consumption expenditure did not differ when different consumption equivalence scales were applied. CONCLUSION: This study questions the appropriateness of wealth indices as proxies for consumption expenditure. The choice of data included had a greater influence on the wealth index than the method used to weight the data. Despite the limitations of PCA, alternative methods also all had disadvantages
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