1,905 research outputs found
Exciton-phonon scattering and photo-excitation dynamics in J-aggregate microcavities
We have developed a model accounting for the photo-excitation dynamics and
the photoluminescence of strongly coupled J-aggregate microcavities. Our model
is based on a description of the J-aggregate film as a disordered Frenkel
exciton system in which relaxation occurs due to the presence of a thermal bath
of molecular vibrations. In a strongly coupled microcavity exciton-polaritons
are formed, mixing superradiant excitons and cavity photons. The calculation of
the microcavity steady-state photoluminescence, following a CW non resonant
pumping, is carried out. The experimental photoluminescence intensity ratio
between upper and lower polariton branches is accurately reproduced. In
particular both thermal activation of the photoluminescence intensity ratio and
its Rabi splitting dependence are a consequence of the bottleneck in the
relaxation, occurring at the bottom of the excitonic reservoir. The effects due
to radiative channels of decay of excitons and to the presence of a
paritticular set of discrete optical molecular vibrations active in relaxation
processes are investigared.Comment: 8 pages, 6 figure
Tunable quantum spin Hall effect in double quantum wells
The field of topological insulators (TIs) is rapidly growing. Concerning
possible applications, the search for materials with an easily controllable TI
phase is a key issue. The quantum spin Hall effect, characterized by a single
pair of helical edge modes protected by time-reversal symmetry, has been
demonstrated in HgTe-based quantum wells (QWs) with an inverted bandgap. We
analyze the topological properties of a generically coupled HgTe-based double
QW (DQW) and show how in such a system a TI phase can be driven by an
inter-layer bias voltage, even when the individual layers are non-inverted. We
argue, that this system allows for similar (layer-)pseudospin based physics as
in bilayer graphene but with the crucial absence of a valley degeneracy.Comment: 9 pages, 8 figures, extended version (accepted Phys. Rev. B
What is a Gene? A Two Sided View
The need to account for all currently available experimental observations
concerning the gene nature, has reshaped the concept of gene turning it from the
essentially mechanistic unit, predominant during the '70s, into a quite abstract
open and generalized entity, whose contour appears less defined as compared to the
past. Here we propose the essence of the gene to be considered double faced. In
this respect genotypic and phenotypic entities of a gene would coexist and mix
reciprocally. This harmonizes present knowledge with current definitions and
predisposes for remodelling of our thinking as a consequence of future discoveries.
A two sided view of the gene also allows to combine the genetic and epigenetic
aspects in a unique solution, being structural and functional at the same time and
simultaneously able to include the different levels in an overlapping unicum
P298 Comparison between clinical and patient-reported symptoms among Crohn's disease and ulcerative colitis patients
Background: There is no symptom-based patient-reported outcomes (PRO) measurement available in IBD. Disease scores contain a mixture of PRO and physician's observations and have shown serious limitations in clinical trials. Comparison between healthcare professionals (HCP) and patient (P) reports on scores' items is a first step toward disease scores refinement. In our IBD cohort study, we were able to collect P and HCP-reported symptoms independently. We assessed the agreement between both measures, and tested the correlation between the general well-being item (GWB) and two health-related quality of life (HRQoL) measures.
Methods: Between 2012 and 2015, we collected CDAI and MTWAI items 1) during follow-up medical visits, 2) through P self-reported follow-up questionnaire, except lab values. We compared items independently reported by HCP and P, stratified by diagnostic and Δt HCP-P reports. We calculated the Cohen's kappa (κ) statistic for agreement. A quadratic weight was applied for more severely serious disagreements. For EIM & complications, we computed a pooled κ based on the average between observed and expected probability of agreement over sub-items. A pooled κ was computed to summarize agreement over all examined variables. We also collected SF-36 and IBDQ scores. Pearson correlation coefficients r were calculated between both scores and GWB reports of HCP and P.
Results: 2427 reports could be evaluated (Δt: 537<1 month, 390 1–2, 1500 2–6), referring to 1385 patients (52% females, 58% CD)
Induced sputum cellularity. Reference values and distribution in normal volunteers.
Abstract
Sputum induction has recently been proposed as the only direct noninvasive method for measuring airway inflammatory indices. The reference values and the distribution of cells in induced sputum in a control population have not yet been well defined. We therefore evaluated data from a large number of healthy volunteers. One hundred fourteen healthy, nonatopic, nonsmoking volunteers without airway hyperreactivity were enrolled (age: 38 +/- 13 yr [mean +/- SD]; FEV(1): 105 +/- 10% predicted; provocative dose of methacholine inducing a 20% decrease FEV(1) > 3,200 microgram). Ninety-six subjects (84%) produced adequate analysis samples. The subjects had a normal age distribution. Their induced sputum was rich in macrophages (69.2 +/- 13%) and neutrophils (27.3 +/- 13%), and poor in eosinophils (0.6 +/- 0.8%), lymphocytes (1.0 +/- 1.2%), and epithelial cells (1.5 +/- 1.8%). Only macrophages and neutrophils showed a normal distribution; total and differential counts of other cells did not. We propose that these data be used in comparison of the induced sputum cells of normal subjects and those of patients with airway inflammation
Gemcitabine plus vinorelbine in elderly or unfit patients with non-small cell lung cancer
Cisplatin-based combinations are efficacious in increasing the overall survival of patients with non-small cell lung cancer (NSCLC), but their toxicity makes them unsuitable for elderly and unfit patients. The primary objective of this non-randomized phase II study was to evaluate the feasibility and activity of the gemcitabine plus vinorelbine combination in previously untreated elderly and/or unfit patients with measurable stage III or IV NSCLC. Forty-three patients aged ≥ 65 years or with contraindications against cisplatin treatment (36 males and seven females: median age 66 years; range 48–75: PS 0 = 11, PS 1 = 19, PS 2 = 13) received intravenous (i.v.) gemcitabine 1000 mg m–2, followed by vinorelbine 25 mg m–2i.v. on day 1 and 8 every 21 days. Fifteen patients (34.9%) achieved partial remission (confidence interval: 27.6–42.2%) for a median duration of 6 months; the median survival of these patients has not yet been reached. A further 15 had stable disease for a median of 4 months and a median survival of 7 months. The 10 patients (23.2%) who experienced disease progression had a median survival of 4 months. Three patients are not evaluable. The 1-year actuarial survival rate is 31.1%. The treatment was well tolerated: only 35% of the patients had grade 3 or 4 granulocytopenia on day 14, none experienced episodes of neutropenic fever, and there was no evidence of severe haematological toxicity upon recycling. Only 9% of the patients suffered from gastrointestinal toxicity (grade 3); increased but reversible transaminase levels were observed in 11.6%. In conclusion, the results of this phase II study show that the combination of gemcitabine and vinorelbine is active and well tolerated in NSCLC, and thus encourage its use in elderly or unfit patients. © 2000 Cancer Research Campaig
Information Needs and Concerns of Patients with Inflammatory Bowel Disease: What Can We Learn from Participants in a Bilingual Clinical Cohort?
BACKGROUND: Inflammatory Bowel Disease (IBD) patients are confronted with needs and concerns related to their disease.
AIM: To explore information expectations of patients included in a national bilingual IBD cohort in Switzerland (SIBDC).
METHODS: This is a mixed-methods study, comprising 1) a semi-narrative survey sent to 1506 patients from the SIBDC and 2) two focus groups conducted with 14 patients to explore and assess the relevance of the survey's findings. Data collected within the framework of the SIBDC was used to characterize survey's responders.
RESULTS: 728 patients (48%) replied to the survey: 52.5% females, 56% Crohn's disease (CD), 87% secondary/tertiary level educated, 70% full/part-time employed. On average, 47% of patients sought for information, regardless of the disease stage; 27% of them were dissatisfied with information received at the time of first symptoms. During flares, 43% were concerned about drugs and therapies; in remission, 57% had concerns on research and developments; 27% searched for information linked to daily disease management. Information-seeking increased when active disease, for CD with high levels of perceived stress (OR = 2.47; p = 0.003), and for all with higher posttraumatic stress symptoms. The focus groups confirmed a perceived lack of information about general functioning, disease course, treatments and their risks, extra-intestinal symptoms and manifestations.
CONCLUSIONS: Information remains insufficient for IBD patients. Lack of information in specific domains can potentially cause stress and hinder detection of symptoms. Better information should be considered as a potentially important component in improving patients' outcomes in IBD
A BRIDGE AMONG HISTORY AND NEW MULTIDISCIPLINARY APPROACHES: THE ROLE OF G.I.S.N. IN THE FIELD OF NEUROMORPHOLOGY
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