1,720,955 research outputs found
The genetic diversity of two ethnically different populations in eastern Sudan based on four single nucleotide polymorphisms in chromosome 5q31-33
No full textThe 5q31-33 contains several genes that are pivotal to the
mounting of appropriate cellular immune responses. Polymorphisms in
this region have been found to be associated with the pathology of several
diseases including malaria, asthma, and hypersensitivity. In order to
understand the genetic profile of 5q31-33 in populations of highly
endemic area for malaria in Sudan we typed four single nucleotide
polymorphisms (SNPS) markers in Hausa and Masalit in eastern Sudan in
a total of 218 chromosomes using ARMS PCR. Allele frequencies were
not significantly different in the two populations, but departure from
Hardy- Weinberg Equilibrium was marked in IL-4, IL-5, IL-9 and IL-13
in Hausa (P=<0.0001, 0.00048, 0.016 and 0.0005) and in Masalit
(P=0.0001, 0.00013, 0.0214 and 0.014). Values suggestive for Linkage
Disequilibrium were observed with the exception of IL-5/IL-13 in
Masalit, which was low (0.4764). In order to investigate possible
association with malaria we compared allele frequencies and
heterozygosity of these SNPS in the families with 0 or low malaria
phenotype as compared to others with high infection rates based on four
independent surveys. The results indicate no correlation. Heterozygosity
was found lower among the less than thirty years age group in Hausa (0.72
and 0.55), and relatively not changed among Masalit (0.69 and 0.70)
Mutation Screening of BRCA2 Gene Exon12 Splicing Site in a Panel of Sudanese Breast Cancer Patients
No full textBreast cancer is one of the major health problems in the Sudan, with high
incidence in females and ranking as the top cancer among females. Several breast cancer
susceptibility genes had been identified; among those are BRCA1 and BRCA2. Breast cancer
is the predominant phenotype associated with mutations in BRCA1 and BRCA2 genes.
However, the rate of mutations within the coding regions of the breast cancer susceptibility
gene BRCA2 does not fairly explain the pathogenecity of the disease, nor accounting for all
12 variant was shown to be detected in normal and disease causing mutations. BRCA2
tumor breast tissues with increased levels of expression measured in the tumor status.
Previous studies suggests that the mechanism generating the BRCA2 mRNA variant in
normal breast tissues might be dysregulated in tumors and such an increase might be caused
by factors at the transcriptional and/or post transcriptional level. The aim of this study was to
detect mutations that might affect the splicing of exon12 of the BRCA2 gene and thus
12 variant in particular and its contribution to the modulating the functions of BRCA2
overall biological functions of BRCA2 in DNA Repair and tumor suppression. DNA was
extracted from peripheral blood of 51 Sudanese breast cancer patients, exon12 was amplified
and subjected to SSCP analysis. Two mutations were confirmed by sequencing in intron12 of
the BRCA2 gene. One of the detected mutations was a deletion and the other was an insertion
in an area expected to serve as sequence context for splicing. However, no mutations were
detected in the canonical splice sites. According to in silico prediction analysis we
hypothesized that the deletion might activate a cryptic 5`splice site that might interfere with
the selection of the authentic 5` splice site leading to skipping of exon12 of the BRCA2
and/or shift the selection towards the cryptic 5`splice site resulting in partial intron retention.
Future functional studies will address this hypothesis and try to make accurate
prediction of the splicing patterns that result from this mutation. Furthermore, the structural
and functional consequences for the corresponding protein will help to understand the role
played by different BRCA2 variants in breast cance
Studies on the bionomics and molecular insecticide resistance of anophelines in Gorgora, north-west Ethiopia
No full textDembia district (wereda) in Gondar, north Ethiopia is one of the malarious areas in the
country. An entomological study was carried out in one of the villages, Gorgora, during
the malaria transmission seasons in 2006 and 2007 with the main objectives of
documenting the species compositions of prevailing anophelines, study the feeding and
resting habits, identify blood meal sources, detect Plasmodium infection, determine the
susceptibility/resistance status of the main malaria vectors and detect the mechanisms of
resistance. Anophelines were captured using Center for Disease Control (CDC) light trapnets,
aspirators, space sprays and pit shelters. Morphological features were used to
discriminate anophelines into species, and the polymerase chain reaction (PCR) was
employed to screen members of the Anopheles gambiae complex. Sprozoite and blood
meal ELISA analysis were carried out to detect infections and identify blood meal
sources. Insecticide susceptibility status of An. arabiensis and An. pharoensis to DDT,
permethrin, deltamethrin and malathion was evaluated using standard bioassay WHO test
kits on adults reared from larvae and pupae. For comparative reasons, An. arabiensis
from Sodere in central and Ghibe River Valley in south west Ethiopia were additionally
included. Colonies were established from surviving individuals for assessing the
occurrence of true as well as cross resistance. Genetic and metabolic resistance
mechanisms on An. arabiensis were investigated by conducting PCR and micro plate
biochemical assays, respectively.
Overall, 5,664 in 2006 and 3,106 in 2007 adult female comprising 9 Anopheles species
were captured predominantly from CDC light trap-nets. The dominant species was An.
pharoensis Theobald comprising 70% of collections in 2006 and 54% in 2007 followed
by An. arabiensis Patton accounting to 20% and 18% in the two consecutive years. The
other species made up the remaining 10% and 28% of collections in those years. The
density of An. arabiensis was highest from July to September and reduced in October and
November, in contrast, An. pharoensis peaked from September to November.
III
CDC trap-nets collected all gonotrophic stages of An. arabiensis and An. pharoensis. The
geometric mean of the blood unfed stages were considered relevant to determine the
human biting rate (HBR) which corresponds to mosquitoes/trap/night, and hence, the
HBR of An. arabiensis during the five months (July-November) in 2006 ranged from the
lowest 0.4 to the highest 0.7 mosquitoes/man/night. The HBR of An. pharoensis for the
same period was between 0.3 and 1.4 mosquitoes/man/night. There was no detectable
difference in biting rates in 2007. From the CDC trap-net collections, blood meals of 255
An. arabiensis and 206 An. pharoensis were analyzed, out of which 64.7% and 36.9%
were found to contain human blood, respectively. The proportion of cattle fed mosquitoes
in that order was 27.5% and 44.7%. The rest of the blood meals contained both mixed
human and cattle or were non-reactive.
Only 4 An. arabiensis were captured from human habitations with aspirator in 2006 and
33 in 2007 using space sprays. Similarly, An. pharoensis was caught in small numbers.
Both species were collected from animal shelters and the density of An. arabiesnsis
varied from 0 to 7.5 mosquitoes/shelter/day while that of An. pharoensis was 0 to 14.8
mosquitoes/shelter/day at different months. However, the latter species density reached to
234 mosquitoes/shelter/day from animal shelters in Toka Agroindustrial Enterprise. It is,
however, difficult to surmise animal shelters in the enterprise serve as resting sites since
fresh fed mosquitoes were collected on window screens in the act of egression. From
animal shelter collections, 59 An. arabiensis and 86 An. pharoensis blood meals were
analyzed. The respective human blood index of the two species was 0.17 (n=1) and 0.58.
(n=5). The proportion fed on cattle was 76.3% (n=45) and 50% (n=46), respectively
while the rest of the blood meals were unidentified either human or bovine.
More than 1000 An. arabiensis and 800 An. pharoensis were examined for parasite
infection against circumsporozoite proteins of Plasmodium falciparum and P. vivax 210
and 247 polymorphs.but none was found with parasite infections.
Insecticide bioassay test results of both mortality and knockdown time revealed very high
DDT resistant An. arabiensis from Ghibe (96.2%) followed by Gorgora (50.5%). DDT
IV
failed to produce 100% knock-down in all test mosquitoes. An. arabiensis from Ghibe
was also greatly resistant to permethrin (69.3%) and deltamethrin (69.7%), while the
strain from Gorgora was less resistant (15-19%). Permethrin was less effective to cause
complete knock-down in the vector from Ghibe while deltamethrin took an elevated KT50
of 37.6 minutes. The respective KT 50 values of the two pyrethroids on An. arabiensis
from Gorgra were 19.6 and 25.3 minutes. The strain from Sodere can be considered
moderately resistant (20%) to DDT and highly susceptible to the pyrethroids if mortality
data are only taken into consideration, however, failure of DDT to knockdown all test
mosquitoes and higher KT50 of 17.8 minutes for permethrin and 21.9 minutes for
deltamethrin indicate presence of considerable resistance which needs regular follow up.
The existence of cross resistance between DDT and permethrin was confirmed on DDT
selected An. arabiensis from Gorgora, where as, it is absent between DDT and
deltamethrin. The West African type kdr mutation was found in the vector population
from Gorgora and Ghibe, and this molecular mechanism probably confers resistance to
DDT and the pyrethroids in addition to metabolic enzymes. Biochemical assays on DDT
selected An. arabiensis from Sodere revealed more glutathione-S-transferase and general
estrases activities than the Debrezeit susceptible strain.
DDT resistance in An. pharoensis from Gorgora was very high reaching up to 93.8%.
The knock-down time for the two pyrethroids is longer than reference susceptible strains.
Both species are susceptible to malathio
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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