12,769 research outputs found
Digital healthcare in COPD management: a narrative review on the advantages, pitfalls, and need for further research
No full textChronic obstructive pulmonary disease (COPD) remains a leading cause of morbidity and mortality despite current treatment strategies which focus on smoking cessation, pulmonary rehabilitation, and symptomatic relief. A focus of COPD care is to encourage self-management, particularly during COVID-19, where much face-to-face care has been reduced or ceased. Digital health solutions may offer affordable and scalable solutions to support COPD patient education and self-management, such solutions could improve clinical outcomes and expand service reach for limited additional cost. However, optimal ways to deliver digital medicine are still in development, and there are a number of important considerations for clinicians, commissioners, and patients to ensure successful implementation of digitally augmented care. In this narrative review, we discuss advantages, pitfalls, and future prospects of digital healthcare, which offer a variety of tools including self-management plans, education videos, inhaler training videos, feedback to patients and healthcare professionals (HCPs), exacerbation monitoring, and pulmonary rehabilitation. We discuss the key issues with sustaining patient and HCP engagement and limiting attrition of use, interoperability with devices, integration into healthcare systems, and ensuring inclusivity and accessibility. We explore the essential areas of research beyond determining safety and efficacy to understand the acceptability of digital healthcare solutions to patients, clinicians, and healthcare systems, and hence ways to improve this and sustain engagement. Finally, we explore the regulatory challenges to ensure quality and engagement and effective integration into current healthcare systems and care pathways, while maintaining patients' autonomy and privacy. Understanding and addressing these issues and successful incorporation of an acceptable, simple, scalable, affordable, and future-proof digital solution into healthcare systems could help remodel global chronic disease management and fractured healthcare systems to provide best patient care and optimisation of healthcare resources to meet the global burden and unmet clinical need of COPD.</p
Applications of microstructured fibre technology in aerospace and defence
No full textThe EMRS DTC project "Photonic Fibres for Active Sensor Systems" aimed to assess the potential impact of microstructured fibres for security and defence applications. Results achieved have suggested enormous potential for these novel fibre types to influence the next generation of photonic systems for security and defence applications. However, it is important to establish where the fibres can offer the greatest advantages and what research still needs to be done to drive the technology towards real platform solutions
sj-docx-1-tar-10.1177_17534666221075493 – Supplemental material for Digital healthcare in COPD management: a narrative review on the advantages, pitfalls, and need for further research
No full textSupplemental material, sj-docx-1-tar-10.1177_17534666221075493 for Digital healthcare in COPD management: a narrative review on the advantages, pitfalls, and need for further research by Alastair Watson and Tom M.A. Wilkinson in Therapeutic Advances in Respiratory Disease</p
Comparing and addressing basic science misconceptions of low achieving students to high achieving students : a Ben Davis High School comparison of students in chemistry honors to students in integrated chemistry and physics
No full textThe idea for this research paper came from discussions in the summer teacher workshops P 691 and P 696 with Professor James Watson. A discussion arose about the number of misconceptions that high school science students would have and whether or not high achieving students would have fewer misconceptions than low achieving students. This research project addresses that summer discussion.The research project has three phases. In phase one of the research project the average number of questions answered correctly in the honors classes will be compared to the average number of questions answered correctly in the integrated chemistry physics class. The second phase will be to compare the number of misconceptions remaining in each class after a week of addressing the misconceptions. The third phase will compare the number of misconceptions after five months in order to see if the new information replaced the old information.Thesis (M.A.)Department of Physics and Astronom
Deep anisotropic dry etching of silicon microstructures by high-density plasmas
No full textThis thesis deals with the dry etching of deep anisotropic microstructures in monocrystalline silicon by high-density plasmas. High aspect ratio trenches are necessary in the fabrication of sensitive inertial devices such as accellerometers and gyroscopes. The etching of silicon in fluorine-based plasmas is isotropic. To obtain anisotropy the addition of sidewall passivation is necessary. This is achieved with both oxygen passivation at low temperatures and fluorocarbon passivation at room temperature. A quantitative approach was pursued to explain the etching mechanism. The etch results were analysed using the measured plasma species fluxes and the surface composition. Moreover, the transport of the plasma species in narrow anisotropic structures is a fundamental factor determining the etch rate and the profile evolution. The experimental methods such as the etching equipment, plasma diagnostics, surface analysis and sample preparation are described in chapter 2. Three etching processes were investigated: the cryogenic etching process with oxygen passivation at low temperatures, the Bosch process with fluorocarbon passivation at room temperature and the novel triple pulse process that was developed in our laboratory. The polymer deposition mechanism and the characteristic role of the ions are also explained. The cryogenic etching process is discussed in chapter 3. Fluorine radicals, oxygen radicals and ion bombardment are responsible for the three main sub-processes, that is, etching, sidewall passivation and depassivation of the trench bottom, respectively. Etching experiments with an extremely low ion-to-radical flux ratio were used to reveal the etching mechanism. Crystal orientation dependent etching leading to Si(111) crystal facets is observed in a surface kinetics controlled regime. By varying the plasma conditions it is possible to adjust the etching mechanism from fluorine-limited to ion-limited. Controlled etching is obtained because the etching is tuned from aspect ratio dependent in the fluorine-limited domain to aspect ratio independent in the ion-limited domain. The transport of radicals in high aspect ratio trenches is an important limiting factor and was investigated with special structures. The etch results are described by an analytic model that is based on the surface site balance of fluorine and oxygen radicals. The results are further explained with a Monte Carlo simulation model. The Bosch process is clarified in chapter 4. The anisotropy of the etched structures is controlled by balancing the etching and passivation pulse. However, the maximal obtainable aspect ratio is limited by convergence of the trench sidewalls due to excessive passivation. The maximal obtainable aspect ratio increases if the ion-to-radical flux ratio increases. The transport of ions is an important limiting factor in the depassivation of the bottom of the trench. Divergence of the ion beam leads to a reduction of the ion flux, so that the fluorocarbon passivation is insufficiently removed near the base of the sidewalls. The average ion angle was measured and correlated to the maximal obtainable aspect ratio. The Bosch process was improved at the depassivation side with the triple pulse process and at the passivation side with preferential sidewall deposition. The triple pulse process that is described in chapter 5 has the aim to improve the depassivation in deep trenches. The three main sub-processes are decoupled using a separate depassivation pulse directly after the etching and passivation pulses. The fluorocarbon passivation is efficiently removed with low-pressure, high-density, oxygen-based plasmas. The investigated plasma chemistries include O2, CO2 and SO2. The triple pulse process leads to better profile control with a straight trench bottom. However, the maximal obtainable aspect ratio is comparable to the Bosch process because a larger etch depth and a small lateral etch cancel out. The polymer deposition mechanism is treated in chapter 6 with the aim to understand the fluorocarbon passivation in deep trenches. The deposition on plane surfaces and on special structures was investigated to distinguish between the radical-induced and ion-enhanced components. A simple analytical model, which explains the main deposition characteristics, was developed. Preferential sidewall deposition is obtained for higher ion fluxes and higher bias voltages where sputtering plays an important role. In this case no fluorocarbon passivation has to be removed from the bottom of the trench. The trench profile was optimised in the Bosch process by tuning the bias voltage during etching and passivation independently. It resulted in perfectly anisotropic trenches but the maximal obtainable aspect ratio was still limited by a small lateral etch. The characteristic role of the ions in the etching mechanism is explained in chapter 7. Ion-induced etching of both SiC in a SF6-O2 plasma and Si in a Cl2 plasma were investigated. The impact of the ions on the profile evolution can be examined more explicitly because spontaneous chemical reactions are absent for these plasma-material systems. The etching mechanism varies from fluorine-limited to ion-limited depending on the radical-to-ion flux ratio. Microtrenches are observed for an ion-limited etching mechanism. Fluorine-limited SiC etching is aspect ratio dependent in contrast to ion-limited SiC etching, which is aspect ratio independent. The etching of high aspect ratio SiC structures is limited by the positive sidewall taper. This is presumably caused by insufficient removal of the thin fluorocarbon layer on the surface. Si etching in a Cl2 plasma is always aspect ratio independent in contrast to SiC etching because of the low reaction probability. The conclusions and recommendations of this thesis are given in chapter 8.Applied Science
Diffraction grating tuning of a high power synchronously pumped PPLN OPO
No full textA diffraction grating is used for tuning a synchronously pumped periodically poled lithium niobate optical parametric oscillator, and its high-output-power performance investigated. Higher order signal modes, caused by pulse-front-tilt, are observed, but are readily suppressed
Synchronously pumped CdSe optical parametric oscillator in the 9-10µm region
No full textContinuous mode-locked operation of a singly resonant, synchronously pumped optical parametric oscillator (SPOPO) based on CdSe has produced idler output tuned over the range of 9.19.7 µm , the longest wavelength generated so far to our knowledge from a SPOPO. Average idler powers as high as 70 mW are generated in the crystal. Tandem pumping with a diffraction-grating-tuned parametric oscillator in periodically poled lithium niobate provides a convenient and agile means of tuning the noncritically phase-matched CdSe device. The absence of any detrimental thermal effects in the CdSe crystal suggests that significant further power scaling should be possible, with idler tuning ranges extendable to cover 812 µm
Synchronously pumped optical parametric oscillator with diffraction-grating tuning
No full textThe operating characteristics of a synchronously pumped optical parametric oscillator, based on periodically poled lithium niobate (PPLN), with a diffraction grating as the tuning element, are described and compared with design expectations. Operation at average signal output power levels of up to 2.0 W has been achieved and signal/idler tuning in the range 1.466-3.663 µm has been investigated using the tilt of the diffraction grating, while keeping the temperature of the PPLN fixed. A detailed investigation has been made of the operating characteristics that might be influenced by the presence of pulse tilt caused by the grating. It is shown that any adverse effects of tilt on beam quality can be small, with the main observed effect being an excess loss. An observed tendency to oscillate in higher-order transverse modes on the long-wavelength side of the tuning range is ascribed to non-collinear phase-matching. This higher-order-mode oscillation is easily prevented by the insertion of an aperture. The analysis presented here includes a grating loss calculation and the calculation of the tuning range achievable with a diffraction grating. The effects of cavity-length change on oscillator performance are also examined and it is found that the grating can give a valuable stabilizing influence by suppressing cavity-length-induced frequency-pulling effects. Extension of the use of gratings from the picosecond to the femtosecond regime is also considered
Agile tuning of a synchronously pumped optical parametric oscillator using a diffraction grating
No full textA synchronously pumped optical parametric oscillator (SPOPO) incorporating an intracavity diffraction grating allows agile tuning (compared with temperature tuning of the nonlinear crystal). Singly resonant operation very close to degeneracy is also readily achieved. We have previously confirmed that the use of the grating is compatible with high power operation (up to 1.6 W of signal output demonstrated)
Synchronously pumped mid-infrared CdSe optical parametric oscillator
No full textSynchronously pumped optical parametric oscillators (SPOPOs) are efficient sources of tunable ultrashort pulses, with low threshold average power requirements, since gain is defined by peak power. An attractive material for such devices is cadmium selenide (CdSe) due to its high nonlinearity (d(31) = 18 pm/V), wide transparency range (0.75-25 µm) and high optical quality. Previous efforts involving CdSe in OPOs have been restricted to angle-tuning, and using Q-switched pump sources. We present here the first continuous-wave, mode-locked SPOPO based on non-critically phase-matched (NCPM) CdSe, with agile tuning of the idler over the range 9.1-9.7 µm, the longest wavelength achieved using a SPOPO to date. Pump-wavelength-tuning over a wide range (necessary for the NCPM arrangement) was provided by the signal output of a periodically poled lithium niobate (PPLN) SPOPO, operating close to degeneracy using a single PPLN grating period. The use of a diffraction grating to tune the signal of the PPLN SPOPO was a key factor in obtaining clean, single-frequency pump conditions, with tuning achieved by simple grating rotation
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