A diamond nanowire single-photon source Lon ar, Marko; Babinec, Thomas M; Hausmann, Birgit J. M ...
Nature nanotechnology,
03/2010, Letnik:
5, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The development of a robust light source that emits one photon at a time will allow new technologies such as secure communication through quantum cryptography. Devices based on fluorescent dye ...molecules, quantum dots and carbon nanotubes have been demonstrated, but none has combined a high single-photon flux with stable, room-temperature operation. Luminescent centres in diamond have recently emerged as a stable alternative, and, in the case of nitrogen-vacancy centres, offer spin quantum bits with optical readout. However, these luminescent centres in bulk diamond crystals have the disadvantage of low photon out-coupling. Here, we demonstrate a single-photon source composed of a nitrogen-vacancy centre in a diamond nanowire, which produces ten times greater flux than bulk diamond devices, while using ten times less power. This result enables a new class of devices for photonic and quantum information processing based on nanostructured diamond, and could have a broader impact in nanoelectromechanical systems, sensing and scanning probe microscopy.
Despite a large body of evidence describing care processes known to reduce the incidence of surgical site infections, many are underutilized in practice.
Fifty-six hospitals volunteered to redesign ...their systems as part of the National Surgical Infection Prevention Collaborative, a 1-year demonstration project sponsored by the Centers for Medicare & Medicaid Services. Each facility selected quality improvement objectives for a select group of surgical procedures and reported monthly clinical process measure data.
Forty-four hospitals reported data on 35,543 surgical cases. Hospitals improved in measures related to appropriate antimicrobial agent selection, timing, and duration; normothermia; oxygenation; euglycemia; and appropriate hair removal. The infection rate decreased 27%, from 2.3% to 1.7% in the first versus last 3 months.
The Collaborative demonstrated improvement in processes known to be associated with reduced risk of surgical site infections. Quality improvement organizations can be effective resources for quality improvement in the surgical arena.
Area-selective atomic layer deposition (AS-ALD) is a promising “bottom-up” alternative to current nanopatterning techniques. Self-assembled monolayers (SAM) have been successfully employed as ...deactivating agents to achieve AS-ALD. In this work, the formation of octadecylphosphonic acid (ODPA) SAMs is studied on four technologically important metal substrates: Cu, Co, W, and Ru. The SAM quality is shown to be dependent on temperature, solvent, and the nature of the substrate. The blocking ability of the ODPA-treated substrates is evaluated using ZnO and Al2O3 model ALD processes. Spectroscopic analyses reveal that ODPA-assisted ALD blocking can be achieved to varying degrees of success on each metal. ODPA-protected W showed >90% selectivity after 32 nm ZnO and 8 nm Al2O3 ALD, exhibiting the best blocking overall. For all substrates, ZnO ALD proved consistently easier to block than Al2O3, indicating the importance of precursor chemistry. Additionally, we show that the self-correcting process previously reported for Cu using an acetic acid etchant can be extended to Co. This process improves selective deposition of Al2O3 on patterned Co/SiO2 with feature sizes as small as 25 nm. Additional studies reveal that feature size and density affect the apparent selectivity in SAM-based AS-ALD, highlighting the importance of such considerations in future process developments.
It is still a matter of debate whether functional cerebral asymmetries (FCA) of many cognitive processes are more pronounced in men than in women. Some evidence suggests that the apparent reduction ...in women's FCA is a result of the fluctuating levels of gonadal steroid hormones over the course of the menstrual cycle, making their FCA less static than for men. The degree of lateralization has been suggested to depend on interhemispheric communication that may be modulated by gonadal steroid hormones. Here, we employed visual-evoked EEG potentials to obtain a direct measure of interhemispheric communication during different phases of the menstrual cycle. The interhemispheric transfer time (IHTT) was estimated from the interhemispheric latency difference of the N170 component of the visual-evoked potential from either left or right visual field presentation. Nineteen right-handed women with regular menstrual cycles were tested twice, once during the menstrual phase, when progesterone and estradiol levels are low, and once during the luteal phase when progesterone and estradiol levels are high. Plasma steroid levels were determined by blood-based immunoassay at each session. It was found that IHTT, in particular from right-to-left, was generally longer during the luteal phase relative to the menstrual phase. This effect occurred as a consequence of a slowed absolute N170 latency of the indirect pathway (i.e. left hemispheric response after LVF stimulation) and, in particular, a shortened latency of the direct pathway (i.e. right hemispheric response after LVF stimulation) during the luteal phase. These results show that cycle-related effects are not restricted to modulation of processes between hemispheres but also apply to cortical interactions, especially within the right hemisphere. The findings support the view that plastic changes in the female brain occur during relatively short-term periods across the menstrual cycle.
•Interhemispheric transfer time (IHTT) fluctuates across the menstrual cycle.•IHTT based on visually evoked N170 latencies was prolonged during the luteal phase.•N170 latencies over the right hemisphere were particularly sensitive to sex hormones.•Sex hormonal fluctuations underlie dynamic changes in women's neural processes.
While opioids are known to cause unintended adverse effects, they are being utilized by a number of patients with osteoarthritis (OA). The aim of this study was to evaluate the association of patient ...familiarity and perceptions regarding efficacy and risks with opioid medication use for OA.
A total of 362 adults with knee and/or hip OA were surveyed in this cross-sectional study. Patients' familiarity with and perceptions of benefits/risks of opioid medications were measured to evaluate potential associations with the utilization of opioid medications for OA within the last 6 months. Logistic regression models were adjusted for sociodemographic and clinical variables.
In this sample, 28.7% (100/349) reported use of an opioid medication for OA-related symptoms in the last 6 months. Those who were on an opioid medication, compared to those who were not, were younger (mean age 62.5 vs 64.8 yrs), were more likely to have a high school education or lower (48.0% vs 35.3%), and had higher mean depression (Patient Health Questionnaire PHQ-8 7.2 vs 4.9) and OA-related pain (Western Ontario and McMaster Universities Arthritis Index WOMAC 54.8 vs 46.8) scores. After adjustment for sociodemographic and clinical variables, the following were associated with opioid medication use: higher perception of medication benefit (OR 1.68, 95% CI 1.18-2.41), lower perception of medication risk (OR 0.67, 95% CI 0.51-0.88), and having family or friends who received the medication for OA (OR 3.88, 95% CI 1.88-8.02).
Among adults with knee/hip OA, opioid use was associated with being familiar with the treatment, as well as believing that the medication was beneficial and low-risk.
Design of the Advanced Rare Isotope Separator ARIS at FRIB Hausmann, M.; Aaron, A.M.; Amthor, A.M. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
12/2013, Letnik:
317
Journal Article
Recenzirano
The Facility for Rare Isotopes Beams (FRIB) at Michigan State University will use projectile fragmentation and induced in-flight fission of heavy-ion primary beams at energies of 200MeV/u and higher ...and at a beam power of 400kW to generate rare isotope beams for experiments in nuclear physics, nuclear astrophysics, and fundamental symmetries, as well as for societal needs. The Advanced Rare Isotope Separator (ARIS) has been designed as a three-stage fragment separator for the efficient collection and purification of the rare isotope beams of interest. A vertically bending preseparator (first stage) with production target and beam dump is fully integrated into a production target facility hot cell with remote handling. The new separator compresses the accepted momentum width of up to ±5% of the beam by a factor of three in the standard operational mode. Provisions for alternate operational modes for specific cases are included in the design. This preseparator is followed by two, horizontally-bending separator stages (second and third stages) utilizing the magnets from the existing A1900 fragment separator at the National Superconducting Cyclotron Laboratory (NSCL). These stages can alternatively be coupled to a single high-resolution separator stage, resulting in the flexibility to optimize the operation for different experiments, including momentum tagging and in-flight particle identification of rare isotope beams. The design of ARIS will be presented with an emphasis on beam physics characteristics, and anticipated operational modes will be described.
The surface reactions during atomic layer deposition (ALD) of SiNx were studied using in situ attenuated total reflection Fourier transform infrared spectroscopy. Specifically, ...di(sec‐butylamino)silane (DSBAS) and bis(diethylamino)silane (BDEAS) were used as the silicon precursors with N
2 plasma as the nitrogen source for SiN
x ALD over a temperature range of 225–375°C. The infrared spectra recorded during each ALD half‐cycle provide unambiguous experimental evidence that surface secondary amines (>NH) are the primary reactive sites for chemisorption of DSBAS and BDEAS on a SiN
x surface that was exposed to an N
2 plasma. Based on these observations, we predict that most aminosilane precursors will primarily react with surface >NH groups: This observation is contrary to most atomistic‐level simulations for this reaction that predict a high activation energy barrier.
Infrared spectra recorded during each atomic layer deposition half‐cycle provide unambiguous experimental evidence that surface secondary amines (>NH) are the primary reactive sites for chemisorption of DSBAS and BDEAS on a SiNx surface that was exposed to an N
2 plasma. Based on these observations, we predict that most aminosilane precursors will primarily react with surface >NH groups: This observation is contrary to most atomistic‐level simulations for this reaction that predict a high activation energy barrier.
This study investigates the role of students' sense of belonging to their university in college student retention. Using individual growth curve modeling, we examined (a) whether sense of belonging ...predicts intentions to persist, and (b) the effects of an intervention designed to enhance students' sense of belonging. African American and white first-year students completed surveys three times throughout the academic year. Students were randomly assigned to a group that received an intervention to enhance students' sense of belonging or to one of two control groups. Sense of belonging was found to predict intentions to persist, controlling for background variables and other predictors of persistence. Overall, sense of belonging and intentions to persist declined over the academic year. However, the decline in sense of belonging was smaller for students in the intervention group. Implications for the development of college retention programs and for existing models of student persistence are discussed.
IntroductionImplementation researchers could draw from participatory research to engage patients (consumers of healthcare) in implementation processes and possibly reduce healthcare disparities. ...There is a little consumer involvement in healthcare implementation, partially because no formal guidance exists. We will create and pilot a toolkit of methods to engage consumers from the US’ Veterans Health Administration (VHA) in selecting and tailoring implementation strategies. This toolkit, Consumer Voice, will provide guidance on what, when, where, how and why an implementer might engage consumers in implementing treatments. We will pilot the toolkit by implementing Safety Planning Intervention for suicide prevention with rural veterans, a population with suicide disparities. Safety Planning Intervention is effective for reducing suicidal behaviours.Methods and analysisIn Aim 1, we will use participatory approaches and user-centred design to develop Consumer Voice and its methods. In Aim 2, we will pilot Consumer Voice by implementing the Safety Planning Intervention in two clinics serving rural VHA patients. One site will receive a current implementation strategy (Implementation Facilitation) only; the second will receive Implementation Facilitation plus Consumer Voice. We will use mixed methods to assess feasibility and acceptability of Consumer Voice. We will compare sites on preliminary implementation (reach, adoption, fidelity) and clinical outcomes (depression severity, suicidal ideation, suicidal behaviour). In Aim 3, we will evaluate Aim 2 outcomes at 20 months to assess sustained impact. We will gather qualitative data on sustainability of the Safety Planning Intervention.Ethics and disseminationThese studies are overseen by the Institutional Review Board at the Central Arkansas Veterans Healthcare System. We plan to use traditional academic modalities of dissemination (eg, conferences, publications). We plan to disseminate findings through meetings with other trainers in implementation practice so they may adopt Consumer Voice. We plan to share results with local community boards.
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