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Radiation-induced damage and instabilities in back-illuminated silicon detectors have proved to be challenging in multiple NASA and commercial applications. In this paper, we develop a model of detector quantum efficiency (QE) as a function of Si-SiO2 interface and oxide trap densities to analyze the performance of silicon detectors and explore the requirements for stable, radiation-hardened surface passivation. By analyzing QE data acquired before, during, and after, exposure to damaging UV radiation, we explore the physical and chemical mechanisms underlying UV-induced surface damage, variable surface charge, QE, and stability in ion-implanted and delta-doped detectors. Delta-doped CCD and CMOS image sensors are shown to be uniquely hardened against surface damage caused by ionizing radiation, enabling the stability and photometric accuracy required by NASA for exoplanet science and time domain astronomy.
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We report the use of aluminum patterning to make highly selective UV bandpass filters. We design and fabricate a periodic array of nanoholes in Al thin film on a bare silicon substrate as an analog for potential integration with a Si photodetector. Arrays were designed to operate in the wavelength range of 200-400 nm. Our results show that we can obtain a single dominant peak filter with a linewidth of 30 nm at normal incidence, in contrast to similar structures on glass substrates, where multiple modes influence the UV spectrum. Varying the angle of incidence is shown to split the plasmonic mode and further decrease the linewidth of the maximum wavelength mode down to 10 nm. Our results therefore show high potential for applications in solid-state image sensors for astronomy and planetary studies.
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Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100-300 nm range for detectors with simple AR coatings, and QE â 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness.
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We report on the fabrication of metal-dielectric thin film stacks deposited directly onto silicon substrates for use as ultraviolet bandpass filters. Integration of these filters onto silicon improves the admittance matching of the structure when compared to similar designs fabricated on transparent substrates, leading to higher peak transmission or improved out-of-band rejection if used with a Si-based sensor platform. Test structures fabricated with metallic Al and atomic layer deposited Al2O3 were characterized with spectroscopic ellipsometry and agree well with optical models. These models predict transmission as high as 90% the spectral range of 200-300 nm for simple three-layer coatings.
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Objectives: There is no standardized protocol for performing educational point-of-care ultrasonography (POCUS) that addresses patient-centered ethical issues such as obtaining informed consent. This study sought to define principles for ethical application of educational POCUS and develop consensus-based best practice guidance. Methods: A questionnaire was developed by a trained ethicist after literature review with the help of a medical librarian. A diverse panel including experts in medical education, law, and bioethics; medical trainees; and individuals with no medical background was convened. The panel voted on their level of agreement with ethical principles and degree of appropriateness of behaviors in three rounds of a modified Delphi process. A high level of agreement was defined as 80% or greater consensus. Results: Panelists voted on 38 total items: 15 related to the patient consent and selection process, eight related to practices while performing educational POCUS, and 15 scenarios involving POCUS application. A high level of agreement was achieved for 13 items related to patient consent and selection, eight items related to performance practices, and 10 scenarios of POCUS application. Conclusions: Based on expert consensus, ethical best practices include obtaining informed consent before performing educational POCUS, allowing patients to decline educational POCUS, informing patients the examination is not intended to be a part of their medical evaluation and is not billed, using appropriate draping techniques, maintaining a professional environment, and disclosing incidental findings in coordination with the primary team caring for the patient. These practices could be implemented at institutions to encourage ethical use of educational POCUS when training physicians, fellows, residents, and medical students.
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2- and 3-photon excitation of components of the lower Rydberg states of iodomethane (CH3I) using linearly and circularly polarized light, followed by ionization with one more photon, is used to determine their molecular term symbol, Ω, values as well as quantum defects. These Ω values, together with a detailed theoretical analysis, require a re-assignment of the 7s and 8s states to various components of the 5d and 6d states, but there is evidence of (n+2)s∕nd hybridization in the pairs of Ω = 1 states. Predissociation sets in for all Rydberg states beyond 6d based on the ground ((2)Π(3∕2)) state of the core, but sharp autoionizing resonances based on the (2)Π(1∕2) core state are assigned to the 9s, 7d, and 5f states. The dominant effect of the singlet∕triplet character of the Rydberg states on their accessibility from the ground state, seen in bromomethane and chloromethane, is again apparent and a concordant interpretation of the Rydberg spectra of CH3I can now be presented. Evidence for coupling of some Ω = 1 and Ω = 0(+) Rydberg states with a repulsive valence state and an ion-pair state, respectively, is also put forward.
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Nitroglycerin, a fast-acting vasodilator, is commonly used as a first-line agent for angina in the emergency department and to manage chest pain due to acute coronary syndromes. It is also a treatment option for other disease states such as acute heart failure, pulmonary edema, and aortic dissection. Nitroglycerin is converted to nitric oxide, a potent vasodilator, in the body, leading to venodilation at lower dosages and arteriodilation at higher dosages that results in both preload and afterload reduction, respectively. Although nitroglycerin has historically been administered as a sublingual tablet and/or spray, it is often given intravenously in the emergency department as this enables titration to effect with predictable pharmacokinetics. In this review article, we outline the indications, mechanism of action, contraindications, and adverse effects of nitroglycerin as well as review relevant literature and make general recommendations regarding the use of nitroglycerin in the emergency department.
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OBJECTIVE: Traditional treatment of abscesses in the emergency department includes packing with gauze; however, this can add pain and discomfort to the procedure and frequently involves a follow-up visit for packing removal. Alternatives to gauze packing have been proposed, but they may have disadvantages in the context of emergency care. The objective of this pilot study was to investigate the use of a novel silicone packing device - the Derma-Stent. METHODS: This was a randomized controlled pilot study of 50 patients from two urban emergency departments with uncomplicated superficial abscesses. The primary outcome was the likelihood of self-removal of packing gauze versus the silicone device. Secondary outcome measures included subjective clinician and patient metrics, such as pain and ease of use. RESULTS: Patients identified with simple cutaneous abscesses were randomized to intervention (packing with the novel silicone device, n=25) or standard care (gauze packing, n=25). Mean age was 36 years, 54% were female, and 96% identified as African American. Although it took longer to place, the silicone device (19.0 vs 15.3 minutes, p=0.03), pain scores were significantly lower (4.3/10 vs 7.1/10, p=0.008) and ease of use reported by physicians better in the silicone-device group (4.8/5 vs 4.0/5, p=0.002). A high unknown rate in the gauze-packing group limits discussion of the likelihood of self-removal; however, the silicone device was more likely to remain in place (60%) versus the gauze packing at 3 days (24%, p=0.01). CONCLUSION: This pilot randomized controlled trial compared the treatment of packing cutaneous abscesses with gauze versus using the silicone device. Limitations in the data prevent discussion on likelihood of self-removal. However, the silicone device was more likely to remain in place at day 3 follow-up and was equally effective to gauze packing in abscess reduction while also improving patient-reported pain scores. It did take longer to place the silicone device; however, physicians reported better ease of use and removal. This pilot study is encouraging for additional larger-scale trials that are required to further assess the utility of this device in the emergency department.
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Surface fluorination and volatilization using hydrogen fluoride and trimethyaluminum (TMA) is a useful approach to the thermal atomic layer etching of Al2O3. We have previously shown that significant enhancement of the TMA etching effect occurs when performed in the presence of lithium fluoride chamber-conditioning films. Now, we extend this enhanced approach to other alkali halide compounds including NaCl, KBr, and CsI. These materials are shown to have varying capacities for the efficient removal of AlF3 and ultimately lead to larger effective Al2O3 etch rates at a given substrate temperature. The most effective compounds allow for continuous etching of Al2O3 at substrate temperatures lower than 150 °C, which can be a valuable route for processing temperature-sensitive substrates and for improving the selectivity of the etch over other materials. The strong interaction between TMA and alkali halide materials also results in material-selective thin-film deposition at these reduced substrate temperatures. We discuss possible mechanisms of this etching enhancement and prospects for extending this approach to other material systems. The consequences of using TMA as an ALD and ALE precursor are discussed in the context of interface engineering for alkali-containing substrates such as lithium battery materials.
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Lithium-sulfur (Li-S) batteries offer high theoretical gravimetric capacities at low cost relative to commercial lithium-ion batteries. However, the solubility of intermediate polysulfides in conventional electrolytes leads to irreversible capacity fade via the polysulfide shuttle effect. Highly concentrated solvate electrolytes reduce polysulfide solubility and improve the reductive stability of the electrolyte against Li metal anodes, but reactivity at the Li/solvate electrolyte interface has not been studied in detail. Here, reactivity between the Li metal anode and a solvate electrolyte (4.2 M LiTFSI in acetonitrile) is investigated as a function of temperature. Though reactivity at the Li/electrolyte interface is minimal at room temperature, we show that reactions between Li and the solvate electrolyte significantly impact the solid electrolyte interphase (SEI) impedance, cyclability, and capacity retention in Li-S cells at elevated temperatures. Addition of a fluoroether cosolvent to the solvate electrolyte results in more fluoride in the SEI which minimizes electrolyte decomposition, reduces SEI impedance, and improves cyclability. A 6 nm AlF3 surface coating is employed at the Li anode to further improve interfacial stability at elevated temperatures. The coating enables moderate cyclability in Li-S cells at elevated temperatures but does not protect against capacity fade over time.
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The vacuum ultraviolet laser-excited photoion-pair formation spectrum of CH 3Br has been measured under high resolution in the threshold region. The (2 + 1) and (3 + 1) resonance-enhanced multiphoton ionization spectra in the same energy region are also reported. By comparison of the spectra in this and a more extended region, resonances in the photoion-pair formation spectrum are assigned to p and f Rydberg states. It is concluded that all the structure in the photoion-pair formation spectrum near threshold can be accounted for by members of the Omega = 0 subset of Rydberg states that act as doorway states to the ion channel.
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INTRODUCTION: This analysis evaluates the impact of bundling drug costs into a hypothetic bundled payment. METHODS: An economic model was created for patient vignettes from: advanced-stage III colon cancer and metastatic non-small-cell lung cancer. First quarter 2016 Medicare reimbursement rates were used to calculate the average fee-for-service (FFS) reimbursement for these vignettes. The probabilistic risk faced by practices was captured by the type of patients seen in practices and randomly assigned in a Monte Carlo simulation on the basis of the given distribution of patient types within each cancer. Simulations were replicated 1,000 times. The impact of bundled payments that include drug costs for various practice sizes and cancer types was quantified as the probability of incurring a loss at four magnitudes: any loss, > 10%, > 20%, or > 30%. A loss was defined as receiving revenue from the bundle that was less than what the practice would have received under FFS; the probability of loss was calculated on the basis of the number of times a practice reported a loss among the 1,000 simulations. RESULTS: Practices that treat a substantial proportion of patients with complex disease compared with the average patient in the bundle would have revenue well below that expected from FFS. Practices that treat a disproportionate share of patients with less complex disease, as compared with the average patient in the bundle, would have revenue well above the revenue under FFS. Overall, bundled payments put practices at greater risk than FFS because their patient case mix could greatly skew financial performance. CONCLUSION: Including drug costs in a bundle is subject to the uncontrollable probabilistic risk of patient case mixes.
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Custos de Medicamentos , Gastos em Saúde , Oncologia/economia , Modelos Econômicos , Pacotes de Assistência ao Paciente/economia , Humanos , Medicare/economia , Mecanismo de Reembolso , Estados UnidosRESUMO
Although palliative care is not new to health care or to oncology, oncologists still struggle to maximize the value of this type of care across the entire care continuum and across the patient's trajectory of illness. When we don't use what may be the best tools for the job, at the right times in the care path, we miss opportunities to optimize patient and family coping, to limit suffering, and to ensure that our care plans are patient centered. In this article, we look at how we define palliative care and how the tools of palliative medicine can be used to enhance patient care in the outpatient oncology practice setting.
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Neoplasias/terapia , Cuidados Paliativos , Qualidade de Vida , Humanos , Assistência TerminalRESUMO
The AVBCC Annual Meeting experiences exponential growth in attendance and participation as oncologists, payers, employers, managed care executives, patient advocates, and drug manufacturers convened in Hollywood, FL, on May 2-5, 2013, for the Third Annual Conference of the Association for Value-Based Cancer Care (AVBCC). The conference presented an all-inclusive open forum for stakeholder dialogue and integration across the cancer care continuum, facilitating an open dialogue among the various healthcare stakeholders to align their perspectives around the urgent need to address value in cancer care, costs, patient education, safety, outcomes, and quality. The AVBCC 2013 Steering Committee was held on the first day of the conference to define value in cancer care. The committee was divided into 7 groups, each representing a key stakeholder in oncology. The goal of the Steering Committee was to define value from the particular point of view of each of the stakeholder groups and to suggest how that particular perspective can contribute to the value proposition in oncology, by balancing cost, quality, and access to care to improve overall patient outcomes. The following summary highlights the major points addressed by each group.