2,561 research outputs found
Van Der Waals Density Functional Study Of Co2 Binding In Zeolitic Imidazolate Frameworks
The van der Waals density functional (vdW-DF) formalism is employed in a study of the binding energetics for CO2 in a set of five zeolitic imidazolate framework (ZIF) compounds. The ZIF structures investigated share the same RHO-type zeolite topology and metal atoms, but feature imidazolate linkers with different chemical functionalization. Three distinct binding sites are identified, for which the binding energies are found to show different dependencies on the functionalization of the linker molecules. The origin of the variations in the binding energies across the ZIF compounds is discussed through analyses of the binding geometries and charge-density distributions. A comparison of the vdW-DF results with those obtained by generalized-gradient-approximation calculations highlights the important contribution of the nonlocal correlation energy to the CO2 binding energies in these compounds
van der Waals density functional study of CO2 binding in zeolitic imidazolate frameworks
This is the publisher's version, also available electronically from http://journals.aps.org/prb/abstract/10.1103/PhysRevB.85.085410The van der Waals density functional (vdW-DF) formalism is employed in a study of the binding energetics for CO2 in a set of five zeolitic imidazolate framework (ZIF) compounds. The ZIF structures investigated share the same RHO-type zeolite topology and metal atoms, but feature imidazolate linkers with different chemical functionalization. Three distinct binding sites are identified, for which the binding energies are found to show different dependencies on the functionalization of the linker molecules. The origin of the variations in the binding energies across the ZIF compounds is discussed through analyses of the binding geometries and charge-density distributions. A comparison of the vdW-DF results with those obtained by generalized-gradient-approximation calculations highlights the important contribution of the nonlocal correlation energy to the CO2 binding energies in these compounds
Intransitivity and coexistence in four species cyclic games
Intransitivity is a property of connected, oriented graphs representing
species interactions that may drive their coexistence even in the presence of
competition, the standard example being the three species Rock-Paper-Scissors
game. We consider here a generalization with four species, the minimum number
of species allowing other interactions beyond the single loop (one predator,
one prey). We show that, contrary to the mean field prediction, on a square
lattice the model presents a transition, as the parameter setting the rate at
which one species invades another changes, from a coexistence to a state in
which one species gets extinct. Such a dependence on the invasion rates shows
that the interaction graph structure alone is not enough to predict the outcome
of such models. In addition, different invasion rates permit to tune the level
of transitiveness, indicating that for the coexistence of all species to
persist, there must be a minimum amount of intransitivity.Comment: Final, published versio
Vitamin D Status and Supplementation Practices in Elite Irish Athletes: An Update from 2010/11.
Vitamin D deficiency is a global health concern that is prevalent in Ireland. The vitamin D status of elite Irish athletes following implementation of a revised supplementation policy in 2010/2011 has not been explored to date. This study aimed to assess the vitamin D status of elite Irish athletes participating in high-profile sports and establish if equatorial travel, supplementation and/or sunbed use predict vitamin D status. Across Ireland, blood samples (n = 92) were obtained from cricketers (n = 28), boxers (n = 21) and women’s rugby sevens players (n = 43) between November 2013 and April 2015. Total 25-hydroxyvitamin D (25(OH)D) concentrations were quantified using LC-MS/MS. Parathyroid hormone and adjusted calcium concentrations were measured by clinical biochemistry. Athletes completed a questionnaire that queried equatorial travel, supplementation and sunbed use. Vitamin D sufficiency (25(OH)D >50 nmol/L) was evident in 86% of athletes. Insufficiency (31–49 nmol/L) and deficiency (<30 nmol/L) was present in only 12% and 2% of athletes respectively. On average, athletes from all sport disciplines were vitamin D sufficient and 25% reported vitamin D supplementation which was a significant positive predictor of vitamin D status, (OR 4.31; 95% CI 1.18–15.75; p = 0.027). Equatorial travel and sun bed use were reported in 47% and 16% of athletes respectively however these factors did not predict vitamin D status (both p > 0.05). Although different cohorts were assessed, the overall prevalence of vitamin D insufficiency/deficiency was 55% in 2010/2011 compared with only 14% in 2013/2015. Targeted supplementation is highly effective in optimising vitamin D status, negating the need for blanket-supplementation in elite cohorts
EKV mutant connexin 31 associated cell death is mediated by ER stress
The epidermis expresses a number of connexin (Cx) proteins that are implicated in gap junction-mediated cell communication. Distinct dominantly inherited mutations in Cx31 cause the skin disease erythrokeratoderma variabilis (EKV) and hearing loss with or without neuropathy. Functional studies reveal tissue-specific effects of these Cx31 disease-associated mutations. The Cx31 mutants (R42P)Cx31, (C86S)Cx31 and (G12D)Cx31 are associated with EKV and the mutant (66delD)Cx31 with peripheral neuropathy and hearing loss, however the mechanisms of pathogenesis remain to be elucidated. Expression of (R42P)Cx31, (C86S)Cx31 and (G12D)Cx31 in vitro, but not (WT)Cx31 or (66delD)Cx31, cause elevated levels of cell-type specific cell death. Previous studies suggest that Cx-associated cell death may be related to abnormal ‘leaky’ hemichannels but we produced direct evidence against that being the major mechanism. Additionally, our immunocytochemistry showed upregulation of components of the unfolded protein response (UPR) in cells expressing the EKV-associated Cx31 mutants but not (WT)Cx31 or (66delD)Cx31. We conclude that the endoplasmic reticulum (ER) stress leading to the UPR is the main mechanism of mutant Cx31-associated cell death. These results indicate that, in vivo, ER stress may lead to abnormal keratinocyte differentiation and hyperproliferation in EKV patient skin
Acupuncture for cancer pain in adults.
BACKGROUND: Forty percent of individuals with early or intermediate stage cancer and 90% with advanced cancer have moderate to severe pain and up to 70% of patients with cancer pain do not receive adequate pain relief. It has been claimed that acupuncture has a role in management of cancer pain and guidelines exist for treatment of cancer pain with acupuncture.
OBJECTIVES: To evaluate efficacy of acupuncture for relief of cancer-related pain in adults.
SEARCH STRATEGY: CENTRAL, MEDLINE, EMBASE, PsycINFO, AMED, and SPORTDiscus were searched up to November 2010 including non-English language papers.
SELECTION CRITERIA: Randomised controlled trials (RCTs) evaluating any type of invasive acupuncture for pain directly related to cancer in adults of 18 years or over.
DATA COLLECTION AND ANALYSIS: It was planned to pool data to provide an overall measure of effect and to calculate the number needed to treat to benefit, but this was not possible due to heterogeneity. Two review authors (CP, OT) independently extracted data adding it to data extraction sheets. Quality scores were given to studies. Data sheets were compared and discussed with a third review author (MJ) who acted as arbiter. Data analysis was conducted by CP, OT and MJ.
MAIN RESULTS: Three RCTs (204 participants) were included. One high quality study investigated the effect of auricular acupuncture compared with auricular acupuncture at 'placebo' points and with non-invasive vaccaria ear seeds attached at 'placebo' points. Participants in two acupuncture groups were blinded but blinding wasn't possible in the ear seeds group because seeds were attached using tape. This may have biased results in favour of acupuncture groups. Participants in the real acupuncture group had lower pain scores at two month follow-up than either the placebo or ear seeds group.There was high risk of bias in two studies because of low methodological quality. One study comparing acupuncture with medication concluded that both methods were effective in controlling pain, although acupuncture was the most effective. The second study compared acupuncture, point-injection and medication in participants with stomach cancer. Long-term pain relief was reported for both acupuncture and point-injection compared with medication during the last 10 days of treatment. Although both studies have positive results in favour of acupuncture they should be viewed with caution due to methodological limitations, small sample sizes, poor reporting and inadequate analysis.
AUTHORS' CONCLUSIONS: There is insufficient evidence to judge whether acupuncture is effective in treating cancer pain in adults
MethCancerDB – aberrant DNA methylation in human cancer
Early detection, classification and prognosis of human cancers by analysis of CpG methylation carry huge diagnostic potential. MethCancerDB collects and annotates genes and sequences from the abundance of published methylation studies and interlinks them to all methylation-relevant bioinformatical resources. MethCancerDB starts with 4720 entries from 348 sources and is freely accessible at http://www.methcancerdb.net
Statistical Characterization of the Chandra Source Catalog
The first release of the Chandra Source Catalog (CSC) contains ~95,000 X-ray
sources in a total area of ~0.75% of the entire sky, using data from ~3,900
separate ACIS observations of a multitude of different types of X-ray sources.
In order to maximize the scientific benefit of such a large, heterogeneous
data-set, careful characterization of the statistical properties of the
catalog, i.e., completeness, sensitivity, false source rate, and accuracy of
source properties, is required. Characterization efforts of other, large
Chandra catalogs, such as the ChaMP Point Source Catalog (Kim et al. 2007) or
the 2 Mega-second Deep Field Surveys (Alexander et al. 2003), while
informative, cannot serve this purpose, since the CSC analysis procedures are
significantly different and the range of allowable data is much less
restrictive. We describe here the characterization process for the CSC. This
process includes both a comparison of real CSC results with those of other,
deeper Chandra catalogs of the same targets and extensive simulations of
blank-sky and point source populations.Comment: To be published in the Astrophysical Journal Supplement Series (Fig.
52 replaced with a version which astro-ph can convert to PDF without issues.
Antifungal effect of essential oil components against Aspergillus niger when loaded into silica mesoporous supports
BACKGROUND: Essential oil components (EOCs) are known for their antifungal properties; however, their high volatility limits their application as antimicrobial agents. Strategies used for controlling the volatility of EOCs include encapsulation or loading into porous materials. This study evaluated the in vitro antifungal activity of selected EOCs (carvacrol, cinnamaldehyde, eugenol and thymol) against the fungus Aspergillus niger when loaded into MCM-41 and b-cyclodextrin (b-CD).
RESULTS:
Carvacrol and thymol in Mobil Composition of Matter No. 41 (MCM-41) displayed remarkable enhanced antifungal properties in comparison to the pure or b- CD-encapsulated EOCs. In fact, carvacrol and thymol were able to maintain antifungal activity and inhibit fungal growth for 30 days, suggesting better applicability of these EOCs as natural preservatives.
CONCLUSIONS:
The sustained antifungal effect of EOCs encapsulated into silica mesoporous supports was described.The authors wish to express their gratitude to the Government of the Czech Republic (Postdok CZU: ESF and MEYS CZ.1.07/2.3.00/30.0040), to CIGA (Project number: 20132024) and to the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic (research project RVO: 61388963). Beth Green is thanked for language control.Bernardos Bau, A.; Marina, T.; Zacek, P.; Pérez-Esteve, É.; Martínez-Máñez, R.; Lhotka, M.; Kourimská, L.... (2015). Antifungal effect of essential oil components against Aspergillus niger when loaded into silica mesoporous supports. Journal of the Science of Food and Agriculture. 95(14):2824-2831. doi:10.1002/jsfa.7022S28242831951
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