Improving the Affordability of Prescription Medications for People with Chronic Respiratory Disease. An Official American Thoracic Society Policy Statement.

BACKGROUND: Mounting evidence indicates that out-of-pocket costs for prescription medications, particularly among low- and middle-income patients with chronic diseases, are imposing financial burden, reducing medication adherence, and worsening health outcomes. This problem is exacerbated by a paucity of generic alternatives for prevalent lung diseases, such as asthma and chronic obstructive pulmonary disease, as well as high-cost medicines for rare diseases, such as cystic fibrosis. Affordability and access challenges are especially salient in the United States, as citizens of many other countries pay lower prices for and have greater access to prescription medications. METHODS: The American Thoracic Society convened a multidisciplinary committee comprising experts in health policy pharmacoeconomics, behavioral sciences, and clinical care, along with individuals providing industry and patient perspectives. The report and its recommendation were iteratively developed over a year of in-person, telephonic, and electronic deliberation. RESULTS: The committee unanimously recommended the establishment of a publicly funded, politically independent, impartial entity to systematically draft evidence-based pharmaceutical policy recommendations. The goal of this entity would be to generate evidence and action steps to ensure people have equitable and affordable access to prescription medications, to maximize the value of public and private pharmaceutical expenditures on health, to support novel drug development within a market-based economy, and to preserve clinician and patient choice regarding personalized treatment. An immediate priority is to examine the evidence and make recommendations regarding the need to have essential medicines with established clinical benefit from each drug class in all Tier 1 formularies and propose recommendations to reduce barriers to timely generic drug availability. CONCLUSIONS: By making explicit, evidence-based recommendations, the entity can support the establishment of coherent national policies that expand access to affordable medications, improve the health of patients with chronic disease, and optimize the use of public and private resources.

Dependence of the minority-carrier lifetime on the stoichiometry of CdTe using time-resolved photoluminescence and first-principles calculations.

CdTe is one of the most promising materials for thin-film solar cells. However, further improvement of its performance is hindered by its relatively short minority-carrier lifetime. Combining theoretical calculations and experimental measurements, we find that for both intrinsic CdTe and CdTe solar cell devices, longer minority-carrier lifetimes can be achieved under Cd-rich conditions, in contrast to the previous belief that Te-rich conditions are more beneficial. First-principles calculations suggest that the dominant recombination centers limiting the minority-carrier lifetime are the Te antisite and Te interstitial. Therefore, we propose that to optimize the solar cell performance, extrinsic p-type doping (e.g., N, P, or As substitution on Te sites) in CdTe under Cd-rich conditions should be a good approach to simultaneously increase both the minority-carrier lifetime and hole concentration.

Photovoltaics at multi-terawatt scale: Waiting is not an option.

25% annual PV growth is possible over the next decade.

PV in the circular economy, a dynamic framework analyzing technology evolution and reliability impacts.

Rapid, terawatt-scale deployment of photovoltaic (PV) modules is required to decarbonize the energy sector. Despite efficiency and manufacturing improvements, material demand will increase, eventually resulting in waste as deployed modules reach end of life. Circular choices for decommissioned modules could reduce waste and offset virgin materials. We present PV ICE, an open-source python framework using modern reliability data, which tracks module material flows throughout PV life cycles. We provide dynamic baselines capturing PV module and material evolution. PV ICE includes multimodal end of life, circular pathways, and manufacturing losses. We present a validation of the framework and a sensitivity analysis. Results show that manufacturing efficiencies strongly affect material demand, representing >20% of the 9 million tons of waste cumulatively expected by 2050. Reliability and circular pathways represent the best opportunities to reduce waste by 56% while maintaining installed capacity. Shorter-lived modules generate 81% more waste and reduce 2050 capacity by 6%.

Circular economy priorities for photovoltaics in the energy transition.

Among the many ambitious decarbonization goals globally, the US intends grid decarbonization by 2035, requiring 1 TW of installed photovoltaics (PV), up from ~110 GW in 2021. This unprecedented global scale-up will stress existing PV supply chains with increased material and energy demands. By 2050, 1.75 TW of PV in the US cumulatively demands 97 million metric tonnes of virgin material and creates 8 million metric tonnes of life cycle waste. This analysis leverages the PV in Circular Economy tool (PV ICE) to evaluate two circular economy approaches, lifetime extension and closed-loop recycling, on their ability to reduce virgin material demands and life cycle wastes while meeting capacity goals. Modules with 50-year lifetimes can reduce virgin material demand by 3% through reduced deployment. Modules with 15-year lifetimes require an additional 1.2 TW of replacement modules to maintain capacity, increasing virgin material demand and waste unless >90% of module mass is closed-loop recycled. Currently, no PV technology is more than 90% closed-loop recycled. Glass, the majority of mass in all PV technologies and an energy intensive component with a problematic supply chain, should be targeted for a circular redesign. Our work contributes data-backed insights prioritizing circular PV strategies for a sustainable energy transition.

In-line miniature 3D-printed pressure-cycled ventilator maintains respiratory homeostasis in swine with induced acute pulmonary injury.

The COVID-19 pandemic demonstrated the need for inexpensive, easy-to-use, rapidly mass-produced resuscitation devices that could be quickly distributed in areas of critical need. In-line miniature ventilators based on principles of fluidics ventilate patients by automatically oscillating between forced inspiration and assisted expiration as airway pressure changes, requiring only a continuous supply of pressurized oxygen. Here, we designed three miniature ventilator models to operate in specific pressure ranges along a continuum of clinical lung injury (mild, moderate, and severe injury). Three-dimensional (3D)-printed prototype devices evaluated in a lung simulator generated airway pressures, tidal volumes, and minute ventilation within the targeted range for the state of lung disease each was designed to support. In testing in domestic swine before and after induction of pulmonary injury, the ventilators for mild and moderate injury met the design criteria when matched with the appropriate degree of lung injury. Although the ventilator for severe injury provided the specified design pressures, respiratory rate was elevated with reduced minute ventilation, a result of lung compliance below design parameters. Respiratory rate reflected how well each ventilator matched the injury state of the lungs and could guide selection of ventilator models in clinical use. This simple device could help mitigate shortages of conventional ventilators during pandemics and other disasters requiring rapid access to advanced airway management, or in transport applications for hands-free ventilation.

Thermomechanical Lift-Off and Recontacting of CdTe Solar Cells.

Controlled delamination of thin-film photovoltaics (PV) post-growth can reveal interfaces that are critical to device performance yet are poorly understood because of their inaccessibility within the device stack. In this work, we demonstrate a technique to lift off thin-film solar cells from their glass substrates in a clean, reproducible manner by first laminating a polymeric backsheet to the device and then thermally shocking the system at low temperatures ( T ≤ -30 °C). To enable clean delamination of diverse thin-film architectures, a theoretical framework is developed and key process control parameters are identified. Focusing on cadmium telluride (CdTe) devices, we show that the lamination temperature and device architecture control the quality of lift-off, while the rate at which the film stack is removed is controlled by the delamination temperature. Crack-free CdTe devices are removed and successfully recontacted, recovering up to 80% of the original device efficiency. The areal density of these devices is ∼0.4 kg m-2, a reduction of over an order of magnitude relative to their initial weight on glass. The framework developed here provides a pathway toward both the development of inexpensive, flexible PV with high specific power and the study of previously buried interfaces in thin-film architectures.

Patient-centered Outcomes Research in Pulmonary, Critical Care, and Sleep Medicine. An Official American Thoracic Society Workshop Report.

Patient-centered outcomes research (PCOR) represents a paradigm shift in research methods aimed to create the body of evidence that supports clinical practice and informs health care decisions. PCOR integrates patients and other key stakeholders including family members, policy makers, clinicians, and patient advocates and advocacy groups as research partners throughout all stages of the research process. The importance of PCOR has received increased recognition, yet there is little evidence available to help guide researchers interested in the design and conduct of PCOR. In May 2014, we convened a workshop to identify key issues related to designing, conducting, and disseminating findings from PCOR studies. Workshop participants included a diverse group of patients, patient advocates, clinicians (physicians, nurses, psychologists, and advanced practice providers), researchers, administrators, and funders within and beyond the pulmonary, critical care, and sleep medicine communities. Participants identified important issues and considerations to address when undertaking PCOR. In this report, we summarize the results of this workshop to inform members of the pulmonary, sleep, and critical care community interested in participating in PCOR. Key findings include the following: 1) requirements for research to be considered PCOR; 2) the potential significant impact of PCOR on patients, clinicians, and researchers; 3) guiding principles and practical strategies to form successful patient-centered research partnerships, conduct PCOR, and disseminate study results to a broad audience of stakeholders; 4) benefits and challenges of PCOR for researchers; and 5) resources available within the American Thoracic Society to help with the conduct of PCOR.

Two-Dimensional Cadmium Chloride Nanosheets in Cadmium Telluride Solar Cells.

In this study we make use of a liquid nitrogen-based thermomechanical cleavage technique and a surface analysis cluster tool to probe in detail the tin oxide/emitter interface at the front of completed CdTe solar cells. We show that this thermomechanical cleavage occurs within a few angstroms of the SnO2/emitter interface. An unexpectedly high concentration of chlorine at this interface, ∼20%, was determined from a calculation that assumed a uniform chlorine distribution. Angle-resolved X-ray photoelectron spectroscopy was used to further probe the structure of the chlorine-containing layer, revealing that both sides of the cleave location are covered by one-third of a unit cell of pure CdCl2, a thickness corresponding to about one Cl-Cd-Cl molecular layer. We interpret this result in the context of CdCl2 being a true layered material similar to transition-metal dichalcogenides. Exposing cleaved surfaces to water shows that this Cl-Cd-Cl trilayer is soluble, raising questions pertinent to cell reliability. Our work provides new and unanticipated details about the structure and chemistry of front surface interfaces and should prove important to improving materials, processes, and reliability of next-generation CdTe-based solar cells.

Self-compensation in arsenic doping of CdTe.

Efficient p-type doping in CdTe has remained a critical challenge for decades, limiting the performance of CdTe-based semiconductor devices. Arsenic is a promising p-type dopant; however, reproducible doping with high concentration is difficult and carrier lifetime is low. We systematically studied defect structures in As-doped CdTe using high-purity single crystal wafers to investigate the mechanisms that limit p-type doping. Two As-doped CdTe with varying acceptor density and two undoped CdTe were grown in Cd-rich and Te-rich environments. The defect structures were investigated by thermoelectric-effect spectroscopy (TEES), and first-principles calculations were used for identifying and assigning the experimentally observed defects. Measurements revealed activation of As is very low in both As-doped samples with very short lifetimes indicating strong compensation and the presence of significant carrier trapping defects. Defect studies suggest two acceptors and one donor level were introduced by As doping with activation energies at ~88 meV, ~293 meV and ~377 meV. In particular, the peak shown at ~162 K in the TEES spectra is very prominent in both As-doped samples, indicating a signature of AX-center donors. The AX-centers are believed to be responsible for most of the compensation because of their low formation energy and very prominent peak intensity in TEES spectra.

Integrating patients into meaningful real-world research.

Research in respiratory, sleep, and critical care medicine has historically been the domain of scientists and clinicians attempting to understand pathophysiological mechanisms and consequences of disease in an effort to develop effective treatments. This traditional approach of placing scientific rigor before the patient's reality is changing. There is growing recognition of the importance of integrating patient perspectives (e.g., preferences, expectations, and expanded definitions of what constitutes "successful" outcomes) into clinical research to achieve meaningful results for a broader group of stakeholders. This evolution is reflected in the growth of patient-centered organizations and patient advocacy groups that seek to meaningfully integrate patients into the process of prioritizing research needs and creating alliances wherein patients and researchers can partner together to accomplish research goals. In tandem, a growing number of real-world trials (i.e., those with broader, more representative patient populations and routine care pathways) now complement findings from traditional randomized controlled trials and offer new opportunities to design studies that better reflect patients' healthcare preferences and experiences. Patients' perspectives are key determinants of treatment adherence and outcomes, as well as the feasibility and likely value of implementing care pathways. The advent of smartphone and push technologies offer new opportunities for the collection of more patient-centered and ecologically valid patient data, thereby adding new dimensions to meaningfully integrate patients into real-world research.

n-Type transparent conducting films of small molecule and polymer amine doped single-walled carbon nanotubes.

In this report, we investigate the electrical and optical properties of thin conducting films of SWNTs after treatment with small molecule and polymeric amines. Among those tested, we find hydrazine to be the most effective n-type dopant. We use absorbance, Raman, X-ray photoelectron, and nuclear magnetic resonance spectroscopies on thin conducting films and opaque buckypapers treated with hydrazine to study fundamental properties and spectroscopic signatures of n-type SWNTs and compare them to SWNTs treated with nitric acid, a well-characterized p-type dopant. We find that hydrazine physisorbs to the surface of semiconducting and metallic SWNTs and injects large electron concentrations, raising the Fermi level as much as 0.7 eV above that of intrinsic SWNTs. Hydrazine-treated transparent SWNT films display sheet resistances nearly as low as p-type nitric-acid-treated films at similar optical transmittances, demonstrating their potential for use in photovoltaic devices as low work function transparent electron-collecting electrodes.

Controlling the optical properties of plasmonic disordered nanohole silver films.

Disordered nanohole arrays were formed in silver films by colloidal lithography techniques and characterized for their surface-plasmon activity. Careful control of the reagent concentration, deposition solution ionic strength, and assembly time allowed generation of a wide variety of nanohole densities. The fractional coverage of the nanospheres across the surface was varied from 0.05-0.36. Electrical sheet resistance measurements as a function of nanohole coverage fit well to percolation theory indicating that the electrical behavior of the films is determined by bulk silver characteristics. The transmission and reflection spectra were measured as a function of coverage and the results indicate that the optical behavior of the films is dominated by surface plasmon phenomena. Angle-resolved transmission and reflection spectra were measured, yielding insight into the nature of the excitations taking place on the metal films. The tunability of the colloidal lithography assembly method holds much promise as a means to generate customized transparent electrodes with high surface plasmon activity throughout the visible and NIR spectrum over large surface areas.

Reversibility, dopant desorption, and tunneling in the temperature-dependent conductivity of type-separated, conductive carbon nanotube networks.

We present a comprehensive study of the effects of doping and temperature on the conductivity of single-walled carbon nanotube (SWNT) networks. We investigated nearly type-pure networks as well as networks comprising precisely tuned mixtures of metallic and semiconducting tubes. Networks were studied in their as-produced state and after treatments with nitric acid, thionyl chloride, and hydrazine to explore the effects of both intentional and adventitious doping. For intentionally and adventitiously doped networks, the sheet resistance (R(s)) exhibits an irreversible increase with temperature above approximately 350 K. Dopant desorption is shown to be the main cause of this increase and the observed hysteresis in the temperature-dependent resistivity. Both thermal and chemical dedoping produced networks free of hysteresis. Temperature-programmed desorption data showed that dopants are most strongly bound to the metallic tubes and that networks consisting of metallic tubes exhibit the best thermal stability. At temperatures below the dopant desorption threshold, conductivity in the networks is primarily controlled by thermally assisted tunneling through barriers at the intertube or interbundle junctions.