569 research outputs found
Strong coupling between single-electron tunneling and nano-mechanical motion
Nanoscale resonators that oscillate at high frequencies are useful in many
measurement applications. We studied a high-quality mechanical resonator made
from a suspended carbon nanotube driven into motion by applying a periodic
radio frequency potential using a nearby antenna. Single-electron charge
fluctuations created periodic modulations of the mechanical resonance
frequency. A quality factor exceeding 10^5 allows the detection of a shift in
resonance frequency caused by the addition of a single-electron charge on the
nanotube. Additional evidence for the strong coupling of mechanical motion and
electron tunneling is provided by an energy transfer to the electrons causing
mechanical damping and unusual nonlinear behavior. We also discovered that a
direct current through the nanotube spontaneously drives the mechanical
resonator, exerting a force that is coherent with the high-frequency resonant
mechanical motion.Comment: Main text 12 pages, 4 Figures, Supplement 13 pages, 6 Figure
The ethanolamide metabolite of DHA, docosahexaenoylethanolamine, shows immunomodulating effects in mouse peritoneal and RAW264.7 macrophages: evidence for a new link between fish oil and inflammation
Several mechanisms have been proposed for the positive health effects associated with dietary consumption of long-chain n-3 PUFA (n-3 LC-PUFA) including DHA (22 : 6n-3) and EPA (20 : 5n-3). After dietary intake, LC-PUFA are incorporated into membranes and can be converted to their corresponding N-acylethanolamines (NAE). However, little is known on the biological role of these metabolites. In the present study, we tested a series of unsaturated NAE on the lipopolysaccharide (LPS)-induced NO production in RAW264.7 macrophages. Among the compounds tested, docosahexaenoylethanolamine (DHEA), the ethanolamide of DHA, was found to be the most potent inhibitor, inducing a dose-dependent inhibition of NO release. Immune-modulating properties of DHEA were further studied in the same cell line, demonstrating that DHEA significantly suppressed the production of monocyte chemotactic protein-1 (MCP-1), a cytokine playing a pivotal role in chronic inflammation. In LPS-stimulated mouse peritoneal macrophages, DHEA also reduced MCP-1 and NO production. Furthermore, inhibition was also found to take place at a transcriptional level, as gene expression of MCP-1 and inducible NO synthase was inhibited by DHEA. To summarise, in the present study, we showed that DHEA, a DHA-derived NAE metabolite, modulates inflammation by reducing MCP-1 and NO production and expression. These results provide new leads in molecular mechanisms by which DHA can modulate inflammatory processes
Zeeman energy and spin relaxation in a one-electron quantum dot
We have measured the relaxation time, T1, of the spin of a single electron
confined in a semiconductor quantum dot (a proposed quantum bit). In a magnetic
field, applied parallel to the two-dimensional electron gas in which the
quantum dot is defined, Zeeman splitting of the orbital states is directly
observed by measurements of electron transport through the dot. By applying
short voltage pulses, we can populate the excited spin state with one electron
and monitor relaxation of the spin. We find a lower bound on T1 of 50
microseconds at 7.5 T, only limited by our signal-to-noise ratio. A continuous
measurement of the charge on the dot has no observable effect on the spin
relaxation.Comment: Replaced with the version published in Phys. Rev. Let
The association of socioeconomic status on treatment strategy in patients with stage I and II breast cancer in the Netherlands
BACKGROUND: Previous studies have shown that socioeconomic status (SES) influences breast cancer therapy. However, these studies were performed in countries with unequal access to healthcare. Therefore, the aim of this study is to investigate whether SES also contributes to the likelihood of receiving a certain therapy in the Netherlands, a country with supposedly equal access to healthcare. MATERIALS AND METHODS: From the Netherlands Cancer Registry, 105,287 patients with newly diagnosed stage I or II breast cancer diagnosed between 2011 and 2018 were selected for analysis. SES was calculated from the average incomes of each postal code, which were divided into 10 deciles. Primary outcome was the effect of SES on the likelihood of undergoing surgery and secondary outcome was the effect of SES on the likelihood of the type of surgery. Both outcomes were corrected for patient, tumor, and hospital characteristics and were expressed as odds ratio (OR) with 95% confidence interval (CI). RESULTS: SES did not affect the likelihood of a breast cancer patient to undergo surgery (OR 1.00 per 10% stratum). In contrast, increased age and higher tumor stage were the most important factors determining whether patients underwent surgery. Patients with higher SES were less likely to undergo mastectomy (OR 0.98). Additionally, more recently diagnosed patients were less likely to undergo mastectomy (OR 0.93 per year) while patients with higher tumor stage were more likely to undergo mastectomy (OR 3.42). CONCLUSION: SES does not affect whether a patient undergoes surgery; however, higher SES increased the likelihood of BCT
Pumping of vibrational excitations in a Coulomb blockaded suspended carbon nanotube
Low-temperature transport spectroscopy measurements on a suspended few-hole
carbon nanotube quantum dot are presented, showing a gate-dependent harmonic
excitation spectrum which, strikingly, occurs in the Coulomb blockade regime.
The quantized excitation energy corresponds to the scale expected for
longitudinal vibrations of the nanotube. The electronic transport processes are
identified as cotunnel-assisted sequential tunneling, resulting from
non-equilibrium occupation of the mechanical mode. They appear only above a
high-bias threshold at the scale of electronic nanotube excitations. We discuss
models for the pumping process that explain the enhancement of the
non-equilibrium occupation and show that it is connected to a subtle interplay
between electronic and vibrational degrees of freedom
Progression of White Matter Lesion Volume and Health-Related Quality of Life in Patients with Symptomatic Atherosclerotic Disease: The SMART-MR Study
Objectives. Mechanisms influencing the course of physical and mental functioning after an atherosclerotic event are unclear. We examined effects of white matter lesion (WML) activity on changes in functioning in patients with symptomatic atherosclerotic disease.
Methods. In 486 patients (58 ± 9 years) of the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART-MR) study, volumetric WML measurements on 1.5T MRI were performed at baseline and 3.9 ± 0.4 years followup. Functioning was assessed with the modified Short-Form 12 (SF-12) questionnaire. Associations of WML progression with changes in functioning were adjusted for age, sex, and vascular risk factors.
Results. Physical functioning (baseline: 44, 10th–90th percentile 29–55) improved, whereas mental functioning (baseline: 51, 10th–90th percentile 32–60) declined during followup. WML progression (highest quartile versus rest) contributed to a stronger decline in mental functioning (B = −1.76, 95% CI −3.11 to −0.42), but did not influence changes in physical functioning. Conclusions. Progression of WML volume contributes to a decline in mental functioning in patients with symptomatic atherosclerotic disease
Применение генетического алгоритма в задачах адаптации структур данных
Представлена разработанная схема адаптации структур данных в оперативной памяти. Для поиска адаптированной структуры данных предложено применение генетического алгоритма. Определены его особенности. Для растровых изображений с соответствующими заголовками выполнены экспериментальные исследования временной эффективности адаптированных структур данных, времени сходимости генетического алгоритма и условия целесообразности применения адаптации.Представлена розроблена схема адаптації структур даних в оперативній пам’яті. Для пошуку адаптованої структури даних запропоновано застосування генетичного алгоритму. Визначені його особливості. Для растрових зображень з відповідними заголовками виконані експериментальні дослідження часової ефективності адаптованих структур даних, часу збіжності генетичного алгоритму та умови доцільності застосування адаптації.The developed scheme of data structures adaptation in memory is given. To search for an adapted data structure, genetic algorithm is proposed and its characteristics are defined. For raster images with the appropriate headings, experimental studies of the time efficiency of adapted data structures, the convergence time of the genetic algorithm and conditions for feasibility of adapting are performed
A qualitative study on redefining normality in relatives of patients with advanced cancer
OBJECTIVE: To obtain insight into adaptation processes of redefining normality and its influencing factors in relatives of patients with advanced cancer.METHODS: An exploratory qualitative study among relatives of patients with advanced cancer was conducted. Participants were purposively recruited. Ten in-depth individual (relative only) and 16 dyad (relative and patient together) interviews were conducted, transcribed verbatim, and analyzed by means of thematic analysis, drawing on elements of grounded theory, combining both inductive and deductive elements.RESULTS: Two adaptation processes of (redefining) normality were identified: assimilation and accommodation. The latter was found to be the main way of adapting to new events. Assimilative coping strategies entailed "continuing to do the same activities as done before the disease," "difficulty accepting the situation," "avoiding to think about the disease," and "living in the short term." Accommodative strategies involved "arranging practical matters," "thinking about the future," "doing what is feasible," "engaging in new activities," "accepting the situation," "seeking distraction," "living in the short term," and "focusing on what truly matters in life." The interplay between the diagnosis and treatment of cancer, a deteriorating disease status, and the accompanying uncertainty about the future was of influence on the relatives' coping strategies.CONCLUSION: When the new situation is too divergent to assimilate, accommodation may be necessary for relatives to cope with the growing complexity of the consequences of their loved one's illness. Accommodative coping then involves accepting the changing reality and actively making the necessary adjustments to build resilience and cope with the new circumstances.</p
A qualitative study on redefining normality in relatives of patients with advanced cancer
OBJECTIVE: To obtain insight into adaptation processes of redefining normality and its influencing factors in relatives of patients with advanced cancer.METHODS: An exploratory qualitative study among relatives of patients with advanced cancer was conducted. Participants were purposively recruited. Ten in-depth individual (relative only) and 16 dyad (relative and patient together) interviews were conducted, transcribed verbatim, and analyzed by means of thematic analysis, drawing on elements of grounded theory, combining both inductive and deductive elements.RESULTS: Two adaptation processes of (redefining) normality were identified: assimilation and accommodation. The latter was found to be the main way of adapting to new events. Assimilative coping strategies entailed "continuing to do the same activities as done before the disease," "difficulty accepting the situation," "avoiding to think about the disease," and "living in the short term." Accommodative strategies involved "arranging practical matters," "thinking about the future," "doing what is feasible," "engaging in new activities," "accepting the situation," "seeking distraction," "living in the short term," and "focusing on what truly matters in life." The interplay between the diagnosis and treatment of cancer, a deteriorating disease status, and the accompanying uncertainty about the future was of influence on the relatives' coping strategies.CONCLUSION: When the new situation is too divergent to assimilate, accommodation may be necessary for relatives to cope with the growing complexity of the consequences of their loved one's illness. Accommodative coping then involves accepting the changing reality and actively making the necessary adjustments to build resilience and cope with the new circumstances.</p
Perspectives of patients, relatives and nurses on rooming-in for adult patients: A scoping review of the literature
Aim: To explore the perspectives of patients, their relatives and nurses on rooming-in for adult patients. Background: The practice of having family stay overnight with an adult patient in hospital is quite new. To support rooming-in programs, the perspectives from all stakeholders should be taken into account. Methods: All types of studies on rooming-in in adult healthcare settings were included in this scoping review. Rooming-in has been defined as the practice where ‘family members or trusted others are facilitated to continuously stay with the patient and are provided with facilities to sleep in the patient's room’. Results: Seven studies were included: one randomized controlled trial, three qualitative studies, and three correspondence articles. Generally, patients felt safe in the presence of a family member, but could also feel restricted in their freedom and privacy. Family members saw a benefit for the patient, considered rooming-in a moral duty, and were happy to help. Nonetheless, family members reported rooming-in as physically and emotionally stressful. Nurses described that patients were less anxious and more easily adjusted to the hospital environment. Conclusions: The reviewed studies suggest that patients, family members, and nurses have both positive and negative experiences with rooming-in. The concept
- …