3,667 research outputs found
X-ray polarization: General formalism and polarization analysis
The polarization of x-rays plays an outstanding role in experimental
techniques such as non-resonant magnetic x-ray scattering and resonant x-ray
scattering of magnetic and multipolar order. Different instrumental methods
applied to synchrotron light can transform its natural polarization into an
arbitrary polarization state. Several synchrotron applications, in particular
in the field of magnetic and resonant scattering rely on the improvement in the
signal/noise ratio or the deeper insight into the ordered state and the
scattering process made possible through these polarization techniques. Here,
we present the mathematical framework for the description of fully and
partially polarized x-rays, with some applications such as linear x-ray
polarization analysis for the determination of the scattered beam's
polarization, and the Ge K-edge resonant scattering.Comment: 12 pages, 6 figures and 1 table. To be published in proceedings of
the workshop "Resonant Elastic X-ray Scattering", Aussois, France (2011
Role of berries in vascular function : a systematic review of human intervention studies
CONTEXT: Berries are a source of polyphenols with recognized health-promoting activities. Several studies suggest that consumption of berries may improve vascular function. OBJECTIVE: The aim of this systematic review is to provide evidence of short- and long-term benefits of berries on outcomes of vascular function. DATA SOURCES: Human intervention studies were collected from PubMed and Scopus databases. STUDY SELECTION: Studies were eligible if they investigated the effects of acute or chronic berry consumption on one or more markers of vascular function in humans and provided a characterization of the berry polyphenolic content. Only randomized controlled trials were included, and studies were excluded if berries were combined with other foods. DATA EXTRACTION: After selection, 22 randomized controlled trials were included and analyzed, most of which were performed in healthy individuals or patients with cardiovascular risk factors. RESULTS: The overall results seem to suggest a protective role of berries in vascular function, likely dependent on the time of exposure, the type and dose of berry, and the biomarkers analyzed. Flow-mediated dilation and reactive hyperemia index (markers of vascular reactivity) improved following short-term interventions, while pulse wave velocity and augmentation index (markers of arterial stiffness) improved only after medium- to long-term intervention. CONCLUSIONS: Current evidence suggests that berries, at physiological relevant doses, may have a role in the modulation of vascular function and stiffness. High-quality human intervention trials are encouraged in order to strengthen these findings and to better elucidate the mechanisms involved in such modulation
Reliability analysis of wireless sensor network for smart farming applications
Wireless Sensor Networks are subjected to some design constraints (e.g., processing capability, storage memory, energy consumption, fixed deployment, etc.) and to outdoor harsh conditions that deeply affect the network reliability. The aim of this work is to provide a deeper understanding about the way redundancy and node deployment affect the network reliability. In more detail, the paper analyzes the design and implementation of a wireless sensor network for low-power and low-cost applications and calculates its reliability considering the real environmental conditions and the real arrangement of the nodes deployed in the field. The reliability of the system has been evaluated by looking for both hardware failures and communication errors. A reliability prediction based on different handbooks has been carried out to estimate the failure rate of the nodes self-designed and self-developed to be used under harsh environments. Then, using the Fault Tree Analysis the real deployment of the nodes is taken into account considering the Wi-Fi coverage area and the possible communication link between nearby nodes. The findings show how different node arrangements provide significantly different reliability. The positioning is therefore essential in order to obtain maximum performance from a Wireless sensor network
Gross morphometry of the heart of the Common marmoset
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The Callithrix jacchus is a Brazilian endemic species that has been widely used asan experimental model in biomedical research. Anatomical data are necessary to support experimental studies with this species. Eleven hearts of C. jacchus from the German Primate Centre (DPZ) have been studied in order to characterize their gross morphometry and compare them with other animal models and human. Biometric data were also obtained. The mean values for morphometry of the hearts did not show any significant difference between male and female. The relative heart weight was similar to human, bovine and equine species. Considering those aspects, the C. jacchus could be used as non-human primate experimental modelfor biomedical studies on heart.
Symptomatic Medial Exostosis of the Great Toe Distal Phalanx: A Complication Due to Over-correction Following Akin Osteotomy for Hallux Valgus Repair
The authors present the case of a 54-year-old female who developed a painful
compression lesion localized to the medial aspect of the base of the distal
phalanx of the great toe as a complication of hallux valgus surgery. Preoperative
radiographic evaluation of the patient's foot revealed the first ray to be longer
than the second, a 12 degrees first intermetatarsal angle, a 33 degrees hallux
abductus angle, and an exostosis at the medial aspect of the base of the hallux
that was not considered by the surgeon to be important. Correction of the hallux
valgus deformity was performed with a combination of scarf and Akin osteotomies,
and the intermetatarsal and hallux abductus angles reduced to 2 degrees and 8
degrees , respectively. By 2 months postoperative, the patient was complaining of
pain at the medial aspect of the distal phalanx of the hallux associated with
shoe pressure. The pain correlated both clinically and radiologically with the
exostosis at the base of the distal phalanx, and had become symptomatic only
after the hallux had been operatively realigned. At 6 months postoperative,
percutaneous exostectomy was undertaken to remove the exostosis. Pain relief was
complete, thereafter, and after 2 years of postoperative follow-up the patient
remained pain free. The clinical importance of a medial exostosis localized to
the base of the distal phalanx of the hallux must be taken into consideration
whenever hallux valgus correction is undertaken, and this is particularly
important whenever an Akin osteotomy is being considered. Level of Clinical
Evidence: 4
The Comparability of Men Who Have Sex With Men Recruited From Venue-Time-Space Sampling and Facebook: A Cohort Study
Background: Recruiting valid samples of men who have sex with men (MSM) is a key component of the US human immunodeficiency virus (HIV) surveillance and of research studies seeking to improve HIV prevention for MSM. Social media, such as Facebook, may present an opportunity to reach broad samples of MSM, but the extent to which those samples are comparable with men recruited from venue-based, time-space sampling (VBTS) is unknown. Objective: The objective of this study was to assess the comparability of MSM recruited via VBTS and Facebook. Methods: HIV-negative and HIV-positive black and white MSM were recruited from June 2010 to December 2012 using VBTS and Facebook in Atlanta, GA. We compared the self-reported venue attendance, demographic characteristics, sexual and risk behaviors, history of HIV-testing, and HIV and sexually transmitted infection (STI) prevalence between Facebook- and VTBS-recruited MSM overall and by race. Multivariate logistic and negative binomial models estimated age/race adjusted ratios. The Kaplan-Meier method was used to assess 24-month retention. Results: We recruited 803 MSM, of whom 110 (34/110, 30.9% black MSM, 76/110, 69.1% white MSM) were recruited via Facebook and 693 (420/693, 60.6% black MSM, 273/693, 39.4% white MSM) were recruited through VTBS. Facebook recruits had high rates of venue attendance in the previous month (26/34, 77% among black and 71/76, 93% among white MSM; between-race P=.01). MSM recruited on Facebook were generally older, with significant age differences among black MSM (P=.02), but not white MSM (P=.14). … See full text for complete abstract
Impact of dedicated women’s outreach workers (WOWs) on recruitment of women in ACTG clinical studies
Background: Despite efforts by the AIDS Clinical Trials Group (ACTG) to enroll representative numbers of diverse women, participation in ACTG studies in the United States remains largely white and male. To address this gap in women’s participation in ACTG research, a one-year pilot study of dedicated women’s outreach workers (WOWs) was proposed. Objectives: included demonstrating that targeted recruitment efforts can expand community awareness of ACTG research and ensuring successful enrollment of women at the respective clinical research sites. Methods: The pilot study was conducted at two U.S. sites (Rutgers New Jersey Medical School and Emory Ponce de Leon Center in Atlanta, Georgia). The WOWs worked with site personnel to identify and reach out to women living with HIV and/or Hepatitis B or C at their respective sites and encourage them to join a clinical trial registry for those interested in participating in future clinical trials. Results: The Rutgers WOW approached 127 potential participants (of whom 100 joined the WOW registry) and screened 35 participants for open ACTG studies. The Emory WOW approached 120 participants, enrolling 86 into the WOW registry, and screened 51 potential participants for open ACTG studies during the WOW’s tenure. The majority of women screened at both sites were women of color. Conclusions: The WOW study team identified several lessons learned that can inform future efforts to engage women living with HIV in clinical research. First, success in engaging women is proportional to level of funding and institutional support. Second, there is a need for a more gender-inclusive scientific agenda as women are more likely to participate if studies address topics of interest to them. Third, meaningful engagement is a two-way street
Lignin from tree barks: chemical structure and valorization
Lignins from different tree barks, including Norway spruce
(Picea abies), eucalyptus (Eucalyptus globulus), mimosa (Acacia
dealbata) and blackwood acacia (A. melanoxylon), are thoroughly
characterized. The lignin from E. globulus bark is found
to be enriched in syringyl (S) units, with lower amounts of
guaiacyl (G) and p-hydroxyphenyl (H) units (H/G/S ratio of
1:26:73), which produces a lignin that is highly enriched in bether
linkages (83%), whereas those from the two Acacia barks
have similar compositions (H/G/S ratio of &5:50:45), with a
predominance of b-ethers (73–75%) and lower amounts of
condensed carbon–carbon linkages; the lignin from A. dealbata
bark also includes some resorcinol-related compounds, that appear to be incorporated or intimately associated to the polymer.
The lignin from P. abies bark is enriched in G units, with
lower amounts of H units (H/G ratio of 14:86); this lignin is
thus depleted in b-O-4’ alkyl–aryl ether linkages (44%) and enriched
in condensed linkages. Interestingly, this lignin contains
large amounts of hydroxystilbene glucosides that seem to be
integrally incorporated into the lignin structure. This study indicates
that lignins from tree barks can be seen as an interesting
source of valuable phenolic compounds. Moreover, this
study is useful for tailoring conversion technologies for bark
deconstruction and valorizationinfo:eu-repo/semantics/publishedVersio
X-chromosomal haplotype frequencies of four linkage groups in a population of Argentina
DNA samples of hundred ten unrelated anonymized male individuals living in province of Entre Rios, Argentina, were genotyped using Investigador Argus X-12 system (Qiagen) for 12 STRs in four haplogroups. The frequency of most common haplotype was 0.02727, 0.06364, 0.03636, and 0.03636 for haplogroups 1, 2, 3, and 4, respectively. The Match Probability was 6.0E-08 and the mean exclusion chance was 0.999999936. This work presents the first haplotype frequency data for Investigator Argus X-12 system in a population of Argentina
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