722 research outputs found
Quantized Roentgen Effect in Bose-Einstein Condensates
A classical dielectric moving in a charged capacitor can create a magnetic
field (Roentgen effect). A quantum dielectric, however, will not produce a
magnetization, except at vortices. The magnetic field outside the quantum
dielectric appears as the field of quantized monopoles
The Effects of Ethanolic Extract of Handal (Citrullus colocynthis L.) Fruit Pulp on Blood Glucose level in Normal Fasting Rats
Background: Citrullus colocynthis L. is a member of the family Cucurbitaceae. It is widely available in Sudan and traditionally used for treatment of skin infections, diabetes and constipation worldwide.
Objectives: This study aimed to investigate the effects of ethanolic extract of C. colocynthis fruit pulp on blood glucose level in normal fasting rats.
Method: Two groups of rats, each of twenty one were used to study the effects of the extract (300 mg/kg/ml) on fasting blood glucose level (BGL) and glucose tolerance test (GTT).
Results: The oral administration of ethanolic extract of C. colocynthis fruit pulp resulted in a sudden drop in BGL of normal fasting rats after four hours. This was accompanied by some toxic effects appeared as severe diarrhea, followed by deaths of some rats (2/7). Moreover, the administration of the extract did not exhibit a remarkable reduction or improvement in the induced hyperglycemia.
Conclusion: This study showed that, ethanolic extract of C. colocynthis fruit pulp reduced the BGL without significant hypoglycemic effect and the extract appeared to be highly toxic.
The genetic variation of lactase persistence alleles in northeast Africa
Lactase persistence (LP) is a well-studied example of a Mendelian trait under selection in some human groups due to gene-culture co-evolution. We investigated the frequencies of genetic variants linked to LP in Sudanese and South Sudanese populations. These populations have diverse subsistence patterns, and some are dependent on milk to various extents, not only from cows, but also from other livestock such as camels and goats. We sequenced a 316bp region involved in regulating the expression of the LCT gene on chromosome 2, which encompasses five polymorphisms that have been associated with LP. Pastoralist populations showed a higher frequency of LP-associated alleles compared to non-pastoralist groups, hinting at positive selection also in northeast African pastoralists. There was no incidence of the East African LP allele (−14010:C) in the Sudanese groups, and only one heterozygote individual for the European LP allele (−13910:T), suggesting limited recent admixture from these geographic regions. Among the LP variants, the −14009:G variant occurs at the highest frequency among the investigated populations, followed by the −13915:G variant, which is likely of Middle Eastern origin, consistent with Middle Eastern gene-flow to the Sudanese populations. The Beja population of the Beni Amer show three different LP-variants at substantial and similar levels, resulting in one of the greatest frequencies of LP-variants among all populations across the world.Competing Interest StatementThe authors have declared no competing interest.Introduction Results and Discussion - Allele frequencies - Haplotype Structure - Selection Scan Conclusion Materials and Methods - Phasing and imputation to analyze haplotype structure - Locus specific branch length (LSBL
Chaotic dynamics of cold atoms in far-off-resonant donut beam
We describe the classical two dimensinal nonlinear dynamics of cold atoms in
far-off-resonant donut beams. We show that there chaotic dynamics exists for
charge greater than unity, when the intensity of the beam is periodically
modulated. The two dimensional distributions of atoms in plane for
charge two are simulated. We show that the atoms will acumulate on several ring
regions when the system enters to regime of global chaos.Comment: 8 pages, 8 figure
Anaemia and blood transfusion in African children presenting to hospital with severe febrile illness
BACKGROUND: Severe anaemia in children is a leading cause of hospital admission and a major cause of mortality in sub-Saharan Africa, yet there are limited published data on blood transfusion in this vulnerable group. METHODS: We present data from a large controlled trial of fluid resuscitation (Fluid Expansion As Supportive Therapy (FEAST) trial) on the prevalence, clinical features, and transfusion management of anaemia in children presenting to hospitals in three East African countries with serious febrile illness (predominantly malaria and/or sepsis) and impaired peripheral perfusion. RESULTS: Of 3,170 children in the FEAST trial, 3,082 (97%) had baseline haemoglobin (Hb) measurement, 2,346/3,082 (76%) were anaemic (Hb <10 g/dL), and 33% severely anaemic (Hb <5 g/dL). Prevalence of severe anaemia varied from 12% in Kenya to 41% in eastern Uganda. 1,387/3,082 (45%) children were transfused (81% within 8 hours). Adherence to WHO transfusion guidelines was poor. Among severely anaemic children who were not transfused, 52% (54/103) died within 8 hours, and 90% of these deaths occurred within 2.5 hours of randomisation. By 24 hours, 128/1,002 (13%) severely anaemic children had died, compared to 36/501 (7%) and 71/843 (8%) of those with moderate and mild anaemia, respectively. Among children without severe hypotension who were randomised to receive fluid boluses of 0.9% saline or albumin, mortality was increased (10.6% and 10.5%, respectively) compared to controls (7.2%), regardless of admission Hb level. Repeat transfusion varied from ≤2% in Kenya/Tanzania to 6 to 13% at the four Ugandan centres. Adverse reactions to blood were rare (0.4%). CONCLUSIONS: Severe anaemia complicates one third of childhood admissions with serious febrile illness to hospitals in East Africa, and is associated with increased mortality. A high proportion of deaths occurred within 2.5 hours of admission, emphasizing the need for rapid recognition and prompt blood transfusion. Adherence to current WHO transfusion guidelines was poor. The high rates of re-transfusion suggest that 20 mL/kg whole blood or 10 mL/kg packed cells may undertreat a significant proportion of anaemic children. Future evaluation of the impact of a larger volume of transfused blood and optimum transfusion management of children with Hb of <6 g/dL is warranted. Please see related article: http://dx.doi.org/10.1186/s12916-014-0248-5. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12916-014-0246-7) contains supplementary material, which is available to authorized users
The catalase gene differentiates between some strains of Staphylococcus aureus ssp. anaerobius
When to start antiretroviral therapy: The need for an evidence base during early HIV infection
Background
Strategies for use of antiretroviral therapy (ART) have traditionally focused on providing treatment to persons who stand to benefit immediately from initiating the therapy. There is global consensus that any HIV+ person with CD4 counts less than 350 cells/μl should initiate ART. However, it remains controversial whether ART is indicated in asymptomatic HIV-infected persons with CD4 counts above 350 cells/μl, or whether it is more advisable to defer initiation until the CD4 count has dropped to 350 cells/μl. The question of when the best time is to initiate ART during early HIV infection has always been vigorously debated. The lack of an evidence base from randomized trials, in conjunction with varying degrees of therapeutic aggressiveness and optimism tempered by the risks of drug resistance and side effects, has resulted in divided expert opinion and inconsistencies among treatment guidelines. Discussion
On the basis of recent data showing that early ART initiation reduces heterosexual HIV transmission, some countries are considering adopting a strategy of universal treatment of all HIV+ persons irrespective of their CD4 count and whether ART is of benefit to the individual or not, in order to reduce onward HIV transmission. Since ART has been found to be associated with both short-term and long-term toxicity, defining the benefit:risk ratio is the critical missing link in the discussion on earlier use of ART. For early ART initiation to be justified, this ratio must favor benefit over risk. An unfavorable ratio would argue against using early ART. Summary
There is currently no evidence from randomized controlled trials to suggest that a strategy of initiating ART when the CD4 count is above 350 cells/μl (versus deferring initiation to around 350 cells/μl) results in benefit to the HIV+ person and data from observational studies are inconsistent. Large, clinical endpoint-driven randomized studies to determine the individual health benefits versus risks of earlier ART initiation are sorely needed.
The counter-argument to this debate topic can be freely accessed here:
http://www.biomedcentral.com/1741-7015/11/147 webcite
WHO guidelines on fluid resuscitation in children: missing the FEAST data.
The World Health Organization recommendations on management of common childhood illnesses affect the lives of millions of children admitted to hospital worldwide. Its latest guidelines,1 released in May 2013, continue to recommend rapid fluid resuscitation for septic shock, even though the only large controlled trial of this treatment (Fluid Expansion as a Supportive Treatment (FEAST) found that it increased the risk of death in African children.2 A subsequent systematic review of bolus resuscitation in children with shock resulting from severe infection also did not support its use.3 Failure to take this evidence into account is not consistent with WHO’s commitment to systematically and transparently assess evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) process when producing guidelines and could endanger the lives of children
Robust and adjustable C-shaped electron vortex beams
Wavefront engineering is an important quantum technology, often applied to the production of states carrying orbital angular momentum (OAM). Here, we demonstrate the design and production of robust C-shaped beam states carrying OAM, in which the usual doughnut shaped transverse intensity structure of the vortex beam contains an adjustable gap. We find that the presence of the vortex lines in the core of the beam is crucial for maintaining the stability of the C-shape structure during beam propagation. The topological charge of the vortex core controls mainly the size of the C-shape, while its opening angle is related to the presence of vortex-anti-vortex loops. We demonstrate the generation and characterisation of C-shaped electron vortex beams, although the result is equally applicable to other quantum waves. C-shaped electron vortex beams have potential applications in nanoscale fabrication of planar split ring structures and three dimensional chiral structures as well as depth sensing and magnetic field determination through rotation of the gap in the C-shape
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