95 research outputs found
Effects of Diet on LCN2 Expression and Onset of Neuroinflammation in an Alzheimer’s Disease Mice Model
This project covers the findings regarding the impact of diet on lipocalin 2 (LCN2) and the effects it has on neuroinflammation Alzheimer’s Disease (AD). LCN2 is a protein that is critical to the functionality of mitochondria and inflammatory responses. Evidence has shown that mitochondrial dysfunction is a potential central event in driving AD pathogenesis and contributing to formation of pathological hallmarks such as chronic inflammation. Furthermore, studies have shown that LCN2 can be deficient under metabolic conditions such as high-fat-diet (HFD). This study investigates if HFD induces LCN2 deficiency and increased neuroinflammation in an AD mice model
Seasonal variations of hydrographic parameters off the Sudanese coast of the Red Sea, 2009–2015
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Regional Studies in Marine Science 18 (2018): 1-10, doi:10.1016/j.rsma.2017.12.004.The variations of temperature and salinity in the Sudanese coastal zone of the Red Sea are studied for the first time using measurements acquired from survey cruises during 2009–2013 and from a mooring during 2014–2015. The measurements show that temperature and salinity variability above the permanent pycnocline is dominated by seasonal signals, similar in character to seasonal temperature and salinity oscillations observed further north on the eastern side of the Red Sea. Using estimates of heat flux, circulation and horizontal temperature/salinity gradients derived from a number of sources, we determined that the observed seasonal signals of temperature and salinity are not the product of local heat and mass flux alone, but are also due to alongshore advection of waters with spatially varying temperature and salinity. As the temperature and salinity gradients, characterized by warmer and less saline water to the south, exhibit little seasonal variation, the seasonal salinity and temperature variations are closely linked to an observed seasonal oscillation in the along-shore flow, which also has a mean northward component. We find that the inclusion of the advection terms in the heat and mass balance has two principal effects on the computed temperature and salinity series. One is that the steady influx of warmer and less saline water from the south counteracts the long-term trend of declining temperatures and rising salinities computed with only the local surface flux terms, and produces a long-term steady state in temperature and salinity. The second effect is produced by the seasonal alongshore velocity oscillation and most profoundly affects the computed salinity, which shows no seasonal signal without the inclusion of the advective term. In both the observations and computed results, the seasonal salinity signal lags that of temperature by roughly 3 months.The SPS surveys were funded by the Norwegian Norad’s Program for Master Studies and organized by IMR–RSU in Port Sudan. The central Red Sea mooring data were acquired as part of a WHOI–KAUST collaboration funded by Award Nos. USA00001, USA00002, and KSA00011 to the WHOI by the KAUST in the Kingdom of Saudi Arabia. The work of I. Skjelvan and A.M. Omar was partly supported by the Research Council of Norway through the MIMT Center for Research-based Innovation. This work is part of a Ph.D. project at GFI–UiB funded by the Norwegian Quota program
The effect of nano silica on short term drying shrinkage of POFA cement mortars
This study investigates effects of nano silica on short-term drying shrinkage of mortars with palm oil fuel ash (POFA) during the first 28 days of curing. Furthermore, moisture content, hydration volume, and permeability were measured in order to study underlying mechanisms. It was revealed that addition of nano silica to samples with 30% POFA as cement replacement lowered the drying shrinkage by 7.5%. Also, it increased the strength development rate by 15% from 7 to 28 days of curing. Nano silica advantageously affected the shrinkage by refining the microstructure, increasing the hydration volume and lowering free water in cement matrix
Differential Plasmodium falciparum surface antigen expression among children with Malarial Retinopathy
Retinopathy provides a window into the underlying pathology of life-threatening malarial coma (“cerebral malaria”), allowing differentiation between 1) coma caused by sequestration of Plasmodium falciparum-infected erythrocytes in the brain and 2) coma with other underlying causes. Parasite sequestration in the brain is mediated by PfEMP1; a diverse parasite antigen that is inserted into the surface of infected erythrocytes and adheres to various host receptors. PfEMP1 sub-groups called “DC8” and “DC13” have been proposed to cause brain pathology through interactions with endothelial protein C receptor. To test this we profiled PfEMP1 gene expression in parasites from children with clinically defined cerebral malaria, who either had or did not have accompanying retinopathy. We found no evidence for an elevation of DC8 or DC13 PfEMP1 expression in children with retinopathy. However, the proportional expression of a broad subgroup of PfEMP1 called “group A” was elevated in retinopathy patients suggesting that these variants may play a role in the pathology of cerebral malaria. Interventions targeting group A PfEMP1 may be effective at reducing brain pathology
Optimization of power quality monitors in transmission system network
Due to an increase in population growth, more sensitive equipment and the significant usage of electricity. Power quality issues are of paramount importance, in order to get reliable and of high efficient power supply. Among all power disturbances, voltage sags are considered as the most frequent and severe type of disturbances that lead to loss of operation of equipment’s. The power quality monitoring system is the first to consider in power quality assessment and mitigation so as to get a reliable and efficient power supply. Installing power quality monitors in every component of the power system network is not feasible due to economic reasons and its need to be minimized. And then how to get the optimal number and locations of power quality monitors while maintaining system observability becomes an important problem. The aim of this paper is to find the optimal number and location of power quality monitors in the transmission system network. The IEEE 14 bus test system was modelled and simulated using POWERWORLD software, to obtain fault voltage and monitor reach area considering both balanced and unbalanced faults in the system. The optimization formulation problem is also formed and solved using an Integer Programming (IP) algorithm MATLAB toolbox to find the minimum number of Power Quality Monitors (PQMs) in the transmission system that lead to voltage sags, the Sag Occurrence Value (SOV) is used to find the best position of the PQMs. Finally, to prove the proposed Integer Programming (IP) algorithm, this paper end with optimizing the PQMs using Genetic Algorithm (GA) techniques
Breadth of antibodies to Plasmodium falciparum variant surface antigens is associated with immunity in a controlled human malaria infection study
Background: Plasmodium falciparum variant surface antigens (VSAs) contribute to malaria pathogenesis by mediating cytoadhesion of infected red blood cells to the microvasculature endothelium. In this study, we investigated the association between anti-VSA antibodies and clinical outcome in a controlled human malaria infection (CHMI) study.
Method: We used flow cytometry and ELISA to measure levels of IgG antibodies to VSAs of five heterologous and one homologous P. falciparum parasite isolates, and to two PfEMP1 DBLβ domains in blood samples collected a day before the challenge and 14 days after infection. We also measured the ability of an individual’s plasma to inhibit the interaction between PfEMP1 and ICAM1 using competition ELISA. We then assessed the association between the antibody levels, function, and CHMI defined clinical outcome during a 21-day follow-up period post infection using Cox proportional hazards regression.
Results: Antibody levels to the individual isolate VSAs, or to two ICAM1-binding DBLβ domains of PfEMP1, were not associated with a significantly reduced risk of developing parasitemia or of meeting treatment criteria after the challenge after adjusting for exposure. However, anti-VSA antibody breadth (i.e., cumulative response to all the isolates) was a significant predictor of reduced risk of requiring treatment [HR 0.23 (0.10-0.50) p= 0.0002].
Conclusion: The breadth of IgG antibodies to VSAs, but not to individual isolate VSAs, is associated with protection in CHMI
The role of the Barents Sea in the Arctic climate system
Present global warming is amplified in the Arctic and accompanied by unprecedented sea ice decline. Located along the main pathway of Atlantic Water entering the Arctic, the Barents Sea is the site of coupled feedback processes that are important for creating variability in the entire Arctic air-ice-ocean system. As warm Atlantic Water flows through the Barents Sea, it loses heat to the Arctic atmosphere. Warm periods, like today, are associated with high northward heat transport, reduced Arctic sea ice cover, and high surface air temperatures. The cooling of the Atlantic inflow creates dense water sinking to great depths in the Arctic Basins, and ~60% of the Arctic Ocean carbon uptake is removed from the carbon-saturated surface this way. Recently, anomalously large ocean heat transport has reduced sea ice formation in the Barents Sea during winter. The missing Barents Sea winter ice makes up a large part of observed winter Arctic sea ice loss, and in 2050, the Barents Sea is projected to be largely ice free throughout the year, with 4°C summer warming in the formerly ice-covered areas. The heating of the Barents atmosphere plays an important role both in “Arctic amplification” and the Arctic heat budget. The heating also perturbs the large-scale circulation through expansion of the Siberian High northward, with a possible link to recent continental wintertime cooling. Large air-ice-ocean variability is evident in proxy records of past climate conditions, suggesting that the Barents Sea has had an important role in Northern Hemisphere climate for, at least, the last 2500 years
Plasmodium falciparum malaria parasite var gene expression is modified by host antibodies: longitudinal evidence from controlled infections of Kenyan adults with varying natural exposure.
BACKGROUND: The PfEMP1 family of Plasmodium falciparum antigens play a key role in pathogenesis of severe malaria through their insertion into the surface of parasite infected erythrocytes, and adhesion to host cells. Previous studies have suggested that parasites expressing PfEMP1 subclasses group A and DC8, associated with severe malaria, may have a growth advantage in immunologically naïve individuals. However, this idea has not been tested in longitudinal studies. METHODS: Here we assessed expression of the var genes encoding PfEMP1, in parasites sampled from volunteers with varying prior exposure to malaria, following experimental infection by sporozoites (PfSPZ). Using qPCR, we tested for associations between the expression of various var subgroups in surviving parasite populations from each volunteer and 1) the levels of participants' antibodies to infected erythrocytes before challenge infection and 2) the apparent in vivo parasite multiplication rate. RESULTS: We show that 1) expression of var genes encoding for group A and DC8-like PfEMP1 were associated with low levels of antibodies to infected erythrocytes (αIE) before challenge, and 2) expression of a DC8-like CIDRα1.1 domain was associated with higher apparent parasite multiplication rate in a manner that was independent of levels of prior antibodies to infected erythrocytes. CONCLUSIONS: This study provides insight into the role of antibodies to infected erythrocytes surface antigens in the development of naturally acquired immunity and may help explain why specific PfEMP1 variants may be associated with severe malaria. TRIAL REGISTRATION: Pan African Clinical Trial Registry: PACTR201211000433272 . Date of registration: 10th October 2012
TRIPLE-BAND MEANDER LINE ANTENNA FOR GSM, DCS AND UTMS APPLICATIONS
ABSTRACT A compact triple-band meander line antenna for global system for mobile communication (GSM), distributed control system (DCS) and universal mobile telecommunications system (UMTS) applications operating at the frequencies band of 0.9 GHz, 1.8 GHz and 2.1 GHz is designed. Most demanded wireless communication bands are covered in this design for consumer electronics. The resonant frequencies are 0.9 GHz with the return loss of -21.262 dB and the corresponding radiation pattern with maximum gain of 2.09 dBi, 1.8 GHz with the return loss of -19.011 dB and the corresponding radiation pattern with maximum gain of 2.32 dBi, and 2.1 GHz with the return loss of -20.203 dB and the corresponding radiation pattern with maximum gain of 3.7 dBi. The antenna was printed on a FR4 substrate with dielectric constant of 4.7. The simulated result was verified through measurement in which a good agreement between the simulated and measured result was documented. An application example is shown for the proposed design which is an integrated system to detect the level of electromagnetic field radiation at GSM frequencies
Medical applicant general practice experience and career aspirations: a questionnaire study
Background: Increasing access to general practice work experience placements for school students
is a strategy for improving general practice recruitment, despite limited evidence and concerns
surrounding equity of access to general practice experiences.
Aims: To examine the association between undertaking general practice experience and the
perceptions of general practice as an appealing future career among prospective medical applicants.
To identify socioeconomic factors associated with obtaining general practice experience.
Design & setting: Cross-sectional questionnaire study in the UK.
Method: Participants were UK residents aged ≥16 years and seriously considering applying to study
medicine in 2019/2020. They were invited to take part via the University Clinical Aptitude Test (UCAT).
Questionnaire data were analysed using a linear regression of general practice appeal on general
practice experience, adjusting for career motivations and demographics, and a logistic regression of
general practice experience on measures of social capital and demographics.
Results: Of 6391 responders, 4031 were in their last year of school. General practice experience
predicted general practice appeal after adjusting for career motivation and demographics (b = 0.37,
standard error [SE] = 0.06, P<0.00001). General practice experience was more common among
students at private (odds ratio [OR] = 1.65, 95% confidence interval [CI] = 1.31 to 2.08, P<0.0001) or
grammar schools (OR = 1.33, 95% CI = 1.02 to 1.72, P = 0.03) and in the highest socioeconomic group
(OR = 1.62, 95% CI = 1.28 to 2.05, P<0.0001), and less likely among students of ‘other’ ethnicity (OR
= 0.37, 95% CI = 0.20 to 0.67, P = 0.0011).
Conclusion: Having general practice experience prior to medical school was associated with finding
general practice appealing, which supports its utility in recruitment. Applicants from more deprived
backgrounds were less likely to have had a general practice experience, possibly through lack of
accessible opportunities
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