706 research outputs found
Social media use and impact during the holiday travel planning process
Through an empirical study among holiday travellers, residing in the Former Soviet Union Republics, this paper presents a comprehensive view of role and impact of social media on the whole holiday travel planning process: Before, during and after the trip, providing insights on usage levels, scope of use, level of influence and trust. Findings suggest that social media are predominantly used after holidays for experience sharing. It is also shown that there is a strong correlation between perceived level of influence from social media and changes made in holiday plans prior to final decisions. Moreover, it is revealed that user-generated content is perceived as more trustworthy when compared to official tourism websites, travel agents and mass media advertising
Strange Attractors in Dissipative Nambu Mechanics : Classical and Quantum Aspects
We extend the framework of Nambu-Hamiltonian Mechanics to include dissipation
in phase space. We demonstrate that it accommodates the phase space
dynamics of low dimensional dissipative systems such as the much studied Lorenz
and R\"{o}ssler Strange attractors, as well as the more recent constructions of
Chen and Leipnik-Newton. The rotational, volume preserving part of the flow
preserves in time a family of two intersecting surfaces, the so called {\em
Nambu Hamiltonians}. They foliate the entire phase space and are, in turn,
deformed in time by Dissipation which represents their irrotational part of the
flow. It is given by the gradient of a scalar function and is responsible for
the emergence of the Strange Attractors.
Based on our recent work on Quantum Nambu Mechanics, we provide an explicit
quantization of the Lorenz attractor through the introduction of
Non-commutative phase space coordinates as Hermitian matrices in
. They satisfy the commutation relations induced by one of the two
Nambu Hamiltonians, the second one generating a unique time evolution.
Dissipation is incorporated quantum mechanically in a self-consistent way
having the correct classical limit without the introduction of external degrees
of freedom. Due to its volume phase space contraction it violates the quantum
commutation relations. We demonstrate that the Heisenberg-Nambu evolution
equations for the Quantum Lorenz system give rise to an attracting ellipsoid in
the dimensional phase space.Comment: 35 pages, 4 figures, LaTe
Regional differences in prostaglandin E₂ metabolism in human colorectal cancer liver metastases
Background: Prostaglandin (PG) E₂ plays a critical role in colorectal cancer (CRC) progression, including epithelial-mesenchymal transition (EMT). Activity of the rate-limiting enzyme for PGE₂ catabolism (15-hydroxyprostaglandin dehydrogenase [15-PGDH]) is dependent on availability of NAD+. We tested the hypothesis that there is intra-tumoral variability in PGE₂ content, as well as in levels and activity of 15-PGDH, in human CRC liver metastases (CRCLM). To understand possible underlying mechanisms, we investigated the relationship between hypoxia, 15-PGDH and PGE₂ in human CRC cells in vitro. Methods: Tissue from the periphery and centre of 20 human CRCLM was analysed for PGE₂ levels, 15-PGDH and cyclooxygenase (COX)-2 expression, 15-PGDH activity, and NAD+/NADH levels. EMT of LIM1863 human CRC cells was induced by transforming growth factor (TGF) β. Results: PGE₂ levels were significantly higher in the centre of CRCLM compared with peripheral tissue (P = 0.04). There were increased levels of 15-PGDH protein in the centre of CRCLM associated with reduced 15-PGDH activity and low NAD+/NADH levels. There was no significant heterogeneity in COX-2 protein expression. NAD+ availability controlled 15-PGDH activity in human CRC cells in vitro. Hypoxia induced 15-PGDH expression in human CRC cells and promoted EMT, in a similar manner to PGE₂. Combined 15-PGDH expression and loss of membranous E-cadherin (EMT biomarker) were present in the centre of human CRCLM in vivo.Conclusions: There is significant intra-tumoral heterogeneity in PGE₂ content, 15-PGDH activity and NAD+ availability in human CRCLM. Tumour micro-environment (including hypoxia)-driven differences in PGE₂ metabolism should be targeted for novel treatment of advanced CRC
Genome wide association mapping for arabinoxylan content in a collection of tetraploid wheats
BACKGROUND: Arabinoxylans (AXs) are major components of plant cell walls in bread wheat and are important in bread-making and starch extraction. Furthermore, arabinoxylans are components of soluble dietary fibre that has potential health-promoting effects in human nutrition. Despite their high value for human health, few studies have been carried out on the genetics of AX content in durum wheat. RESULTS: The genetic variability of AX content was investigated in a set of 104 tetraploid wheat genotypes and regions attributable to AX content were identified through a genome wide association study (GWAS). The amount of arabinoxylan, expressed as percentage (w/w) of the dry weight of the kernel, ranged from 1.8% to 5.5% with a mean value of 4.0%. The GWAS revealed a total of 37 significant marker-trait associations (MTA), identifying 19 quantitative trait loci (QTL) associated with AX content. The highest number of MTAs was identified on chromosome 5A (seven), where three QTL regions were associated with AX content, while the lowest number of MTAs was detected on chromosomes 2B and 4B, where only one MTA identified a single locus. Conservation of synteny between SNP marker sequences and the annotated genes and proteins in Brachypodium distachyon, Oryza sativa and Sorghum bicolor allowed the identification of nine QTL coincident with candidate genes. These included a glycosyl hydrolase GH35, which encodes Gal7 and a glucosyltransferase GT31 on chromosome 1A; a cluster of GT1 genes on chromosome 2B that includes TaUGT1 and cisZog1; a glycosyl hydrolase that encodes a CelC gene on chromosome 3A; Ugt12887 and TaUGT1genes on chromosome 5A; a (1,3)-β-D-glucan synthase (Gsl12 gene) and a glucosyl hydrolase (Cel8 gene) on chromosome 7A. CONCLUSIONS: This study identifies significant MTAs for the AX content in the grain of tetraploid wheat genotypes. We propose that these may be used for molecular breeding of durum wheat varieties with higher soluble fibre content.Ilaria Marcotuli, Kelly Houston, Robbie Waugh, Geoffrey B. Fincher, Rachel A. Burton, Antonio Blanco, Agata Gadalet
The excess mortality risk of diabetes associated with functional decline in older adults: Results from a 7-year follow-up of a nationwide cohort in Taiwan
<p>Abstract</p> <p>Background</p> <p>Diabetes is associated with an increased risk of functional decline in older adults. Few studies have investigated the contribution of functional decline to excess mortality risk in older people with diabetes. The aim of this study was to examine how diabetes in combination with different levels of functional decline affects 7-year mortality in older adults.</p> <p>Methods</p> <p>We analyzed data from a nationally representative sample of people aged 65 years and over, participating in the 2001 National Health Interview Survey in Taiwan. A total of 1873 participants were followed through 2002-2008, of whom 286 (15.3%) had a history of diabetes confirmed by a medical professional. Participants were divided into three functional status groups: (1) high functioning-no limitations involving activities of daily living (ADLs), instrumental activities of daily living (IADLs), or physical functioning; (2) low functioning-limitations in one or more ADLs; (3) middle functioning-all participants in between groups 1 and 2.</p> <p>Results</p> <p>The crude mortality rate was 52.7 per 1,000 person-years in those with diabetes and 34.1 per 1,000 person-years in those without diabetes. After adjustment for other factors, diabetes alone was not associated with an increased mortality risk in those with high functioning. However, diabetes alone had a hazard ratio (HR) for mortality of 1.90 (95%CI = [1.02-3.53]) in those with middle functioning and 3.67 (95%CI = [1.55-8.69]) in those with low functioning. The presence of diabetes and one or more other chronic conditions was associated with a HR for mortality of 2.46 (95%CI = [1.61-3.77]) in those with middle functioning and 4.03 (95%CI = [2.31-7.03]) in those with low functioning.</p> <p>Conclusions</p> <p>Our results indicate that diabetes is not associated with increased mortality in those with high functioning. There was a gradient effect of functional decline on mortality in individuals with diabetes. Additionally, among participants with other chronic conditions, functional decline was associated with a greater burden of mortality in older adults with diabetes. These findings highlight the critical importance of the prevention of cardiovascular disease morbidity and the maintenance of functional abilities in order to reduce mortality risk in older adults with diabetes.</p
Genetic changes that increase 5-hydroxymethyl furfural resistance in ethanol-producing Escherichia coli LY180
The ability of a biocatalyst to tolerate furan inhibitors present in hemicellulose hydrolysates is important for the production of renewable chemicals. This study shows EMFR9, a furfural-tolerant mutant of ethanologenic E. coli LY180, has also acquired tolerance to 5-hydroxymethyl furfural (5-HMF). The mechanism of action of 5-HMF and furfural appear similar. Furan tolerance results primarily from lower expression of yqhD and dkgA, two furan reductases with a low Km for NADPH. Furan tolerance was also increased by adding plasmids encoding a NADPH/NADH transhydrogenase (pntAB). Together, these results support the hypothesis that the NADPH-dependent reduction of furans by YqhD and DkgA inhibits growth by competing with biosynthesis for this limiting cofactor
Needs-oriented discharge planning and monitoring for high utilisers of psychiatric services (NODPAM): Design and methods
<p>Abstract</p> <p>Background</p> <p>Attempts to reduce high utilisation of psychiatric inpatient care by targeting the critical time of hospital discharge have been rare.</p> <p>Methods</p> <p>This paper presents design and methods of the study "Effectiveness and Cost-Effectiveness of Needs-Oriented Discharge Planning and Monitoring for High Utilisers of Psychiatric Services" (NODPAM), a multicentre RCT conducted in five psychiatric hospitals in Germany. Inclusion criteria are receipt of inpatient psychiatric care, adult age, diagnosis of schizophrenia or affective disorder, defined high utilisation of psychiatric care during two years prior to the current admission, and given informed consent. Consecutive recruitment started in April 2006. Since then, during a period of 18 months, comprehensive outcome data of 490 participants is being collected at baseline and during three follow-up measurement points.</p> <p>The manualised intervention applies principles of needs-led care and focuses on the inpatient-outpatient transition. A trained intervention worker provides two intervention sessions: (a) Discharge planning: Just before discharge with the patient and responsible clinician at the inpatient service; (b) Monitoring: Three months after discharge with the patient and outpatient clinician. A written treatment plan is signed by all participants after each session.</p> <p>Primary endpoints are whether participants in the intervention group will show fewer hospital days and readmissions to hospital. Secondary endpoints are better compliance with aftercare, better clinical outcome and quality of life, as well as cost-effectiveness and cost-utility.</p> <p>Discussion</p> <p>If a needs-oriented discharge planning and monitoring proves to be successful in this RCT, a tool will be at hand to improve patient outcome and reduce costs via harmonising fragmented mental health service provision.</p> <p>Trial Registration</p> <p>ISRCTN59603527</p
Effect of Mitomycin - C and Triamcinolone on Preventing Urethral Strictures
Urethral stricture is a common disease with high recurrence rate. Several manipulations were defined to prevent the recurrence but the results were disappointing. This study aimed to evaluate the efficacy of triamcinolone and mitomycin-C on urethral stricture formation and their effect on inhibition of urethral fibrosis. A total of 24 New Zealand rabbits were divided into 3 groups. Urethras of rabbits were traumatized with pediatric resectoscope. Resection area was irrigated with 10mL saline, swapped with a cotton wool soaked with 0.5mg/mL MMC and injected by 40mg triamcinolone in groups 1, 2 and 3 respectively. Retrograde urethrogram was performed at 28th day of procedure and the urethra was removed for histopathologic evaluation. There were significant differences in urethral diameters and in lumen reduction rate between the control and study groups (p< 0.001). Compared to control group, all treatment groups showed mild fibrosis, less collagen bundle irregularity, and lower numbers of fibroblasts (p= 0.003). The Tunnel assay showed that the number of apoptotic cells in the submucosal connective tissue was quantitatively higher in control groups (p= 0.034). In the view of efficacy and safety, MMC and triamcinolone have the potential to replace the use of stents, clean intermittent catheterization, or long term catheters following internal urethrotomy. There were no statistically significant differences between two agents in terms of preventing urethral stricture formation in the present study. Mitomycin C and triamcinolone decreased the recurrence rates of urethral stricture
c-erbB2/neu gene and chromosome 17 analysis in breast cancer by FISH on archival cytological fine-needle aspirates
Is endobronchial ultrasound-guided transbronchial needle aspiration with a stylet necessary for lymph node screening in lung cancer patients?
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