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1.
Adv Mater ; 36(15): e2309672, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38206096

RESUMEN

Development of both organic photovoltaics (OPVs) and organic photocatalysts has focused on utilizing the bulk heterojunction (BHJ). The BHJ promotes charge separation and enhances the carrier lifetime, but may give rise to increased charge traps, hindering performance. Here, high photocatalytic and photovoltaic performance is displayed by electron donor-acceptor (D-A) nanoparticles (NPs) and films, using the nonfullerene acceptor Y6 and polymer donor PIDT-T8BT. In contrast to conventional D-A systems, the charge generation in PIDT-T8BT:Y6 NPs is mainly driven by Y6, allowing a high performance even at a low D:A mass ratio of 1:50. The high performance at the low mass ratio is attributed to the amorphous behavior of PIDT-T8BT. Low ratios are generally thought to yield lower efficiency than the more conventional ≈1:1 ratio. However, the OPVs exhibit peak performance at a D:A ratio of 1:5. Similarly the NPs used for photocatalytic hydrogen evolution show peak performance at the 1:6.7 D:A ratio. Interestingly, for the PIDT-T8BT:Y6 system, as the polymer proportion increases, a reduced photocatalytic and photovoltaic performance is observed. The unconventional D:A ratios provide lower recombination losses and increased charge-carrier lifetime with undisrupted ambipolar charge transport in bulk Y6, enabling better performance than conventional ratios. This work reports novel light-harvesting materials in which performance is reduced due to unfavorable morphology as D:A ratios move toward conventional ratios of 1:1.2-1:1.

2.
BMJ Open ; 14(1): e077690, 2024 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-38238062

RESUMEN

INTRODUCTION: COVID-19 underscored the importance of field epidemiology training programmes (FETPs) as countries struggled with overwhelming demands. Experts are calling for more field epidemiologists with better training. Since 1951, FETPs have been building public health capacities across the globe, yet explorations of learning in these programmes are lacking. This qualitative study will (1) describe approaches to training field epidemiologists in FETP; (2) describe strategies for learning field epidemiology among FETP trainees and (3) explain the principles and practices aligning training approaches with learning strategies in FETP. METHODS AND ANALYSIS: The research design, implementation and interpretation are collaborative efforts with FETP trainers. Data collection will include interviews with FETP trainers and trainees and participant observations of FETP training and learning events in four FETP in the Western Pacific Region. Data analysis will occur in three phases: (1) we will use the constant comparison method of Charmaz's grounded theory during open coding to identify and prioritise categories and properties in the data; (2) during focused coding, we will use constant comparison and Polkinghorne's analysis of narratives, comparing stories of prioritised categories, to fill out properties of those categories and (3) we will use Polkinghorne's narrative analysis to construct narratives that reflect domains of interest, identifying correspondence among Carr and Kemmis's practices, understandings and situations to explain principles and processes of learning in FETP. ETHICS AND DISSEMINATION: We have obtained the required ethics approvals to conduct this research at The Australian National University (2021/771) and Taiwan's Ministry of Health and Welfare (112206). Data will not be available publicly, but anonymised findings will be shared with FETP for collaborative interpretation. Ultimately, findings and interpretations will appear in peer-reviewed journals and conferences.


Asunto(s)
Epidemiólogos , Vigilancia de la Población , Humanos , Australia , Salud Pública/educación , Investigación Cualitativa
3.
Ann Am Thorac Soc ; 21(1): 68-75, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37916873

RESUMEN

Rationale: Nonbenzodiazepine benzodiazepine receptor agonists (NBZRA, e.g., zolpidem) are frequently used to treat insomnia among patients with chronic obstructive pulmonary disease (COPD). However, multiple observational studies find that patients with COPD who are prescribed NBZRAs have greater risks for mortality and respiratory complications than patients without such prescriptions. Without an active comparator, these studies are susceptible to confounding by indication. Objectives: Compare the risk of death or inpatient COPD exacerbation among patients receiving zolpidem relative to patients receiving other hypnotics. Methods: Using nationwide Veterans Health Administration (VA) data, we identified patients with clinically diagnosed COPD and new receipt of zolpidem or another hypnotic available on VA formulary without prior authorization (melatonin, trazodone, doxepin). We excluded those receiving traditional benzodiazepines or multiple concurrent hypnotics. We propensity-matched patients receiving zolpidem to other hypnotics on 32 variables, including demographics, comorbidities, and markers of COPD severity. We compared risk of the primary composite outcome of death or inpatient COPD exacerbation over 1 year. In secondary analyses, we propensity-matched patients receiving zolpidem to those without hypnotic receipt. Results: Among 283,740 patients meeting inclusion criteria, 1,126 (0.4%) received zolpidem and 3,057 (1.1%) received other hypnotics. We propensity-matched patients receiving zolpidem 1:1 to peers receiving other hypnotics. We did not find a difference in the primary composite outcome of death or inpatient exacerbation (hazard ratio, 0.97; 95% confidence interval [CI], 0.77-1.23). In secondary analyses comparing patients receiving zolpidem to matched peers without hypnotic receipt, we observed greater risk of death or inpatient exacerbation with zolpidem (hazard ratio, 1.40; 95% CI, 1.09-1.81). Conclusions: Among patients with COPD, we did not observe greater risks after new receipt of zolpidem relative to other hypnotics. However, we did observe greater risks relative to those without hypnotic receipt. This latter finding may reflect: 1) residual, unmeasured confounding related to insomnia; or 2) true adverse effects of hypnotics across classes. Future work is needed to better understand the risks of hypnotics in COPD.


Asunto(s)
Enfermedad Pulmonar Obstructiva Crónica , Trastornos del Inicio y del Mantenimiento del Sueño , Humanos , Zolpidem , Trastornos del Inicio y del Mantenimiento del Sueño/tratamiento farmacológico , Hipnóticos y Sedantes/efectos adversos , Benzodiazepinas/efectos adversos , Enfermedad Pulmonar Obstructiva Crónica/complicaciones , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico
4.
Chest ; 165(2): 381-388, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37832783

RESUMEN

BACKGROUND: The lung allocation score (LAS) is a tool used to prioritize patients for lung transplantation. For patients with interstitial lung diseases (ILDs), spirometry data are used for the LAS calculation. Spirometry values such as a FVC are subjected to race-specific equations that determine expected values. The effect of race-specific equations in LAS score remains unknown. RESEARCH QUESTION: Did the use of a race-based spirometry equation lead to longer waitlist times for Black patients? STUDY DESIGN AND METHODS: We performed a retrospective analysis of patients listed for lung transplantation from 2005 through 2020 using publicly available data from the United Network for Organ Sharing. We recalculated LAS scores for Black patients using White-specific equations with the available variables. The primary objective was to evaluate the effect of race-specific equations on LAS scores and time on the transplant waitlist. RESULTS: A total of 33,845 patients listed for lung transplantation were included in the analysis. White patients were listed at lower LAS scores, a higher proportion of White patients underwent transplantation, and White patients died on the waitlist at lower rates. When recalculating LAS scores using White-specific equations, Black patients with ILD had up to a 1.9-point higher score, which resulted in additional waitlist time. INTERPRETATION: Race-specific equations led to longer wait times in Black patients listed for lung transplantation. The use of race-based equations widened already known disparities in pulmonary transplantation.


Asunto(s)
Enfermedades Pulmonares Intersticiales , Trasplante de Pulmón , Espirometría , Obtención de Tejidos y Órganos , Listas de Espera , Humanos , Enfermedades Pulmonares Intersticiales/cirugía , Estudios Retrospectivos , Negro o Afroamericano , Disparidades en Atención de Salud
5.
Redox Biol ; 69: 103000, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38150990

RESUMEN

In the cytosol of human cells under low oxidative loads, hydrogen peroxide is confined to microdomains around its supply sites, due to its fast consumption by peroxiredoxins. So are the sulfenic and disulfide forms of the 2-Cys peroxiredoxins, according to a previous theoretical analysis [Travasso et al., Redox Biology 15 (2017) 297]. Here, an extended reaction-diffusion model that for the first time considers the differential properties of human peroxiredoxins 1 and 2 and the thioredoxin redox cycle predicts important new aspects of the dynamics of redox microdomains. The peroxiredoxin 1 sulfenates and disulfides are more localized than the corresponding peroxiredoxin 2 forms, due to the former peroxiredoxin's faster resolution step. The thioredoxin disulfides are also localized. As the H2O2 supply rate (vsup) approaches and then surpasses the maximal rate of the thioredoxin/thioredoxin reductase system (V), these concentration gradients become shallower, and then vanish. At low vsup the peroxiredoxin concentration determines the H2O2 concentrations and gradient length scale, but as vsup approaches V, the thioredoxin reductase activity gains influence. A differential mobility of peroxiredoxin disulfide dimers vs. reduced decamers enhances the redox polarity of the cytosol: as vsup approaches V, reduced decamers are preferentially retained far from H2O2 sources, attenuating the local H2O2 buildup. Substantial total protein concentration gradients of both peroxiredoxins emerge under these conditions, and the concentration of reduced peroxiredoxin 1 far from the H2O2 sources even increases with vsup. Altogether, the properties of 2-Cys peroxiredoxins and thioredoxin are such that localized H2O2 supply induces a redox and functional polarization between source-proximal regions (redox microdomains) that facilitate peroxiredoxin-mediated signaling and distal regions that maximize antioxidant protection.


Asunto(s)
Antioxidantes , Peroxirredoxinas , Humanos , Antioxidantes/metabolismo , Peroxirredoxinas/metabolismo , Peróxido de Hidrógeno/metabolismo , Reductasa de Tiorredoxina-Disulfuro/metabolismo , Oxidación-Reducción , Tiorredoxinas/metabolismo , Disulfuros/metabolismo
6.
Ann Am Thorac Soc ; 20(11): 1642-1653, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37579136

RESUMEN

Rationale: Many advocate the application of propensity-matching methods to real-world data to answer key questions around obstructive sleep apnea (OSA) management. One such question is whether identifying undiagnosed OSA impacts mortality in high-risk populations, such as those with chronic obstructive pulmonary disease (COPD). Objectives: Assess the association of sleep testing with mortality among patients with COPD and a high likelihood of undiagnosed OSA. Methods: We identified patients with COPD and a high likelihood of undiagnosed OSA. We then distinguished those receiving sleep testing within 90 days of index COPD encounters. We calculated propensity scores for testing based on 37 variables and compared long-term mortality in matched groups. In sensitivity analyses, we compared mortality using inverse propensity weighting and instrumental variable methods. We also compared the incidence of nonfatal events including adverse outcomes (hospitalizations and COPD exacerbations) and routine services that are regularly indicated in COPD (influenza vaccination and pulmonary function testing). We compared the incidence of each nonfatal event as a composite outcome with death and separately compared the marginal probability of each nonfatal event independently, with death as a competing risk. Results: Among 135,958 patients, 1,957 (1.4%) received sleep testing. We propensity matched all patients with sleep testing to an equal number without testing, achieving excellent balance on observed confounders, with standardized differences < 0.10. We observed lower mortality risk among patients with sleep testing (incidence rate ratio, 0.88; 95% confidence interval [CI], 0.79-0.99) and similar results using inverse propensity weighting and instrumental variable methods. Contrary to mortality, we found that sleep testing was associated with a similar or greater risk for nonfatal adverse events, including inpatient COPD exacerbations (subhazard ratio, 1.29; 95% CI, 1.02-1.62) and routine services like influenza vaccination (subhazard ratio, 1.26; 95% CI, 1.17-1.36). Conclusions: Our disparate findings can be interpreted in multiple ways. Sleep testing may indeed cause both reduced mortality and greater incidence of nonfatal adverse outcomes and routine services. However, it is also possible that our findings stem from residual confounding by patients' likelihood of accessing care. Given the limitations of propensity-based analyses, we cannot confidently distinguish these two possibilities. This uncertainty highlights the limitations of using propensity-based analyses to guide patient care and policy decisions.


Asunto(s)
Gripe Humana , Enfermedad Pulmonar Obstructiva Crónica , Apnea Obstructiva del Sueño , Humanos , Factores de Riesgo , Apnea Obstructiva del Sueño/complicaciones , Apnea Obstructiva del Sueño/epidemiología , Apnea Obstructiva del Sueño/diagnóstico , Sueño
7.
Contemp Clin Trials ; 132: 107303, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37481201

RESUMEN

Chronic obstructive pulmonary disease (COPD) is one of the most common comorbid diseases among aging people with HIV (PWH) and is often mismanaged. To address this gap, we are conducting the study, "Advancing care for COPD in people living with HIV by Implementing Evidence-based management through proactive E-consults (ACHIEVE)." This intervention optimizes COPD management by promoting effective, evidence-based care and de-implementing inappropriate therapies for COPD in PWH receiving care at Veteran Affairs (VA) medical centers. Study pulmonologists are proactively supporting ID providers managing a population of PWH who have COPD, offering real-time evidence-based recommendations tailored to each patient. We are leveraging VA clinical and informatics infrastructures to communicate recommendations between the study team and clinical providers through the electronic health record (EHR) as an E-consult. If effective, ACHIEVE could serve as a model of effective, efficient COPD management among PWH receiving care in VA. This paper outlines the rationale and methodology of the ACHIEVE trial, one of a series of studies funded by the National Heart, Lung, and Blood Institute (NHLBI) within the ImPlementation REsearCh to DEvelop Interventions for People Living with HIV (PRECluDE) consortium to study chronic disease comorbidities in HIV populations.


Asunto(s)
Infecciones por VIH , Enfermedad Pulmonar Obstructiva Crónica , Veteranos , Humanos , Enfermedad Pulmonar Obstructiva Crónica/epidemiología , Enfermedad Pulmonar Obstructiva Crónica/terapia , Enfermedad Crónica , Comorbilidad , Infecciones por VIH/complicaciones , Infecciones por VIH/epidemiología , Infecciones por VIH/terapia
8.
J Am Geriatr Soc ; 71(8): 2539-2548, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37036028

RESUMEN

BACKGROUND: Despite evidence that structured goals of care conversations (GoCCs) and documentation of life-sustaining treatment (LST) preferences improve the delivery of goal-concordant care for seriously ill patients, rates of completion remain low among nursing home residents. The Preferences Elicited and Respected for Seriously Ill Veterans through Enhanced Decision-Making (PERSIVED) program aims to improve the consistent documentation of LST preferences among Veterans receiving care in veterans affairs (VA)-paid community nursing homes (CNH); however, the barriers and facilitators of completing and documenting GoCCs in this unique context of care have not been described. METHODS: We conducted semi-structured, qualitative interviews with key stakeholders of the VA CNH programs located at six VA Medical Centers between July 2021 and July 2022. With a rapid approach to analysis, interview transcripts were reduced into memo templates using the Tailored Implementation for Chronic Disease Checklist and coded and analyzed using qualitative data analysis software. RESULTS: The 40 participants consisted of nurses (n = 13), social workers (n = 25), and VA physicians (n = 2). Most participants felt confident about conducting GoCC; however, several barriers were identified. At the staff level, our results indicated inconsistent completion of GoCC and documentation due to a lack of training, confusion about roles and responsibilities, and challenging communication within the VA as well as with CNH. At the organizational level, there was a lack of standardization across sites for how LST preferences were documented. At the patient level, we found key barriers related to patient and family readiness and issues finding surrogate decision makers. While COVID-19 brought end-of-life issues to the forefront, lockdowns hindered communication about the goals of care. CONCLUSION: Findings from this pre-implementation evaluation revealed multi-level barriers in conducting and documenting GoCCs with Veterans receiving VA-paid CNH care, as well as several facilitators that can be used to inform strategies for improvement.


Asunto(s)
COVID-19 , Veteranos , Estados Unidos , Humanos , United States Department of Veterans Affairs , Control de Enfermedades Transmisibles , Casas de Salud , Planificación de Atención al Paciente , Comunicación , Investigación Cualitativa
9.
JAMA Netw Open ; 6(2): e230589, 2023 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-36826818

RESUMEN

Importance: There have been few studies on the heterogeneous interconnection of COVID-19 outbreaks occurring in different social settings using robust, surveillance epidemiological data. Objectives: To describe the characteristics of COVID-19 transmission within different social settings and to evaluate settings associated with onward transmission to other settings. Design, Setting, and Participants: This is a case series study of laboratory-confirmed COVID-19 cases in Tokyo between January 23 and December 5, 2020, when vaccination was not yet implemented. Using epidemiological investigation data collected by public health centers, epidemiological links were identified and classified into 7 transmission settings: imported, nightlife, dining, workplace, household, health care, and other. Main Outcomes and Measures: The number of cases per setting and the likelihood of generating onward transmissions were compared between different transmission settings. Results: Of the 44 054 confirmed COVID-19 cases in this study, 25 241 (57.3%) were among male patients, and the median (IQR) age of patients was 36 (26-52) years. Transmission settings were identified in 13 122 cases, including 6768 household, 2733 health care, and 1174 nightlife cases. More than 6600 transmission settings were detected, and nightlife (72 of 380 [18.9%]; P < .001) and health care (119 [36.2%]; P < .001) settings were more likely to involve 5 or more cases than dining, workplace, household, and other settings. Nightlife cases appeared in the earlier phase of the epidemic, while household and health care cases appeared later. After adjustment for transmission setting, sex, age group, presence of symptoms, and wave, household and health care cases were less likely to generate onward transmission compared with nightlife cases (household: adjusted odds ratio, 0.03; 95% CI, 0.02-0.05; health care: adjusted odds ratio, 0.57; 95% CI, 0.41-0.79). Household settings were associated with intergenerational transmission, while nonhousehold settings mainly comprised transmission between the same age group. Among 30 932 cases without identified transmission settings, cases with a history of visiting nightlife establishments were more likely to generate onward transmission to nonhousehold settings (adjusted odds ratio, 5.30 [95% CI, 4.64-6.05]; P < .001) than those without such history. Conclusions and Relevance: In this case series study, COVID-19 cases identified in nightlife settings were associated with a higher likelihood of spreading COVID-19 than household and health care cases. Surveillance and interventions targeting nightlife settings should be prioritized to disrupt COVID-19 transmission, especially in the early stage of an epidemic.


Asunto(s)
COVID-19 , Humanos , Masculino , Adulto , Persona de Mediana Edad , SARS-CoV-2 , Tokio , Japón , Brotes de Enfermedades
10.
ACS Appl Mater Interfaces ; 14(42): 47981-47990, 2022 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-36222623

RESUMEN

Atomic-scale information about the structural and compositional properties of novel semiconductor nanowires is essential to tailoring their properties for specific applications, but characterization at this length scale remains a challenging task. Here, quasi-1D InAs/InGaAs semiconductor nanowire arrays were grown by selective area epitaxy (SAE) using molecular beam epitaxy (MBE), and their subsequent properties were analyzed by a combination of atom probe tomography (APT) and aberration-corrected transmission electron microscopy (TEM). Results revealed the chemical composition of the outermost thin InAs layer, a fine variation in the indium content at the InAs/InGaAs interface, and lightly incorporated element tracing. The results highlight the importance of correlative microscopy approaches in revealing complex nanoscale structures, with TEM being uniquely suited to interrogating the crystallography of InGaAs NWs, whereas APT is capable of three-dimensional (3D) elemental mapping, revealing the subtle compositional variation near the boundary region. This work demonstrates a detailed pathway for the nanoscale structural assessment of novel one-dimensional (1D) nanomaterials.

14.
Ultramicroscopy ; 233: 113420, 2021 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-34775241

RESUMEN

Revealing the position of materials with chemical selectivity at atomic scale within functional nanoparticles is essential to understand and control their performance and cutting-edge atom probe tomography is a powerful tool to undertake this task. In this paper, we demonstrate three effective methods to prepare the needle-shaped specimens required for atom probe tomography measurements from nanoparticles of different sizes and provide examples of how atom probe can be used to provide data that is critical to their functionality. Samples measured include lithium-ion batteries (LIBs) cathode nanoparticles (300 - 500 nm), nickel-doped silicon dioxide (Ni@SiO2) catalytic nanoparticles (100 - 200 nm) and tin-doped copper (Sn@Cu) catalytic nanoparticles (<100 nm). The methods presented can be used to address the ongoing challenge of specimen preparation from particle samples for atom probe measurement, and they provide high quality data. These methods will broaden the application of atom probe tomography and will provide alternative option for researchers to assess the performance/structure of their functional nanomaterials.

15.
ACS Appl Mater Interfaces ; 13(48): 57703-57712, 2021 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-34806354

RESUMEN

There is growing interest in the development of novel materials and devices capable of ionizing radiation detection for medical applications. Organic semiconductors are promising candidates to meet the demands of modern detectors, such as low manufacturing costs, mechanical flexibility, and a response to radiation equivalent to human tissue. However, organic semiconductors have typically been employed in applications that convert low energy photons into high current densities, for example, solar cells and LEDs, and thus existing design rules must be re-explored for ionizing radiation detection where high energy photons are converted into typically much lower current densities. In this work, we report the optoelectronic and X-ray dosimetric response of a tissue equivalent organic photodetector fabricated with solution-based inks prepared from polymer donor poly(3-hexylthiophene) (P3HT) blended with either a non-fullerene acceptor (5Z,5'Z)-5,5'-((7,7'-(4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl))bis(methanylylidene))bis(3-ethyl-2-thioxothiazolidin-4-one) (o-IDTBR) or a fullerene acceptor, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Indirect detection of X-rays was achieved via coupling of organic photodiodes with a plastic scintillator. Both detectors displayed an excellent response linearity with dose, with sensitivities to 6 MV photons of 263.4 ± 0.6 and 114.2 ± 0.7 pC/cGy recorded for P3HT:PCBM and P3HT:o-IDTBR detectors, respectively. Both detectors also exhibited a fast temporal response, able to resolve individual 3.6 µs pulses from the linear accelerator. Energy dependence measurements highlighted that the photodetectors were highly tissue equivalent, though an under-response in devices compared to water by up to a factor of 2.3 was found for photon energies of 30-200 keV due to the response of the plastic scintillator. The P3HT:o-IDTBR device exhibited a higher stability to radiation, showing just an 18.4% reduction in performance when exposed to radiation doses of up to 10 kGy. The reported devices provide a successful demonstration of stable, printable, flexible, and tissue-equivalent radiation detectors with energy dependence similar to other scintillator-based detectors used in radiotherapy.


Asunto(s)
Materiales Biomiméticos/química , Polímeros/química , Humanos , Ensayo de Materiales , Estructura Molecular , Radiación Ionizante , Semiconductores , Rayos X
16.
J Synchrotron Radiat ; 28(Pt 5): 1444-1454, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34475292

RESUMEN

Spatially fractionated ultra-high-dose-rate beams used during microbeam radiation therapy (MRT) have been shown to increase the differential response between normal and tumour tissue. Quality assurance of MRT requires a dosimeter that possesses tissue equivalence, high radiation tolerance and spatial resolution. This is currently an unsolved challenge. This work explored the use of a 500 nm thick organic semiconductor for MRT dosimetry on the Imaging and Medical Beamline at the Australian Synchrotron. Three beam filters were used to irradiate the device with peak energies of 48, 76 and 88 keV with respective dose rates of 3668, 500 and 209 Gy s-1. The response of the device stabilized to 30% efficiency after an irradiation dose of 30 kGy, with a 0.5% variation at doses of 35 kGy and higher. The calibration factor after pre-irradiation was determined to be 1.02 ±â€…0.005 µGy per count across all three X-ray energy spectra, demonstrating the unique advantage of using tissue-equivalent materials for dosimetry. The percentage depth dose curve was within ±5% of the PTW microDiamond detector. The broad beam was fractionated into 50 microbeams (50 µm FHWM and 400 µm centre-to-centre distance). For each beam filter, the FWHMs of all 50 microbeams were measured to be 51 ±â€…1.4, 53 ±â€…1.4 and 69 ±â€…1.9 µm, for the highest to lowest dose rate, respectively. The variation in response suggested the photodetector possessed dose-rate dependence. However, its ability to reconstruct the microbeam profile was affected by the presence of additional dose peaks adjacent to the one generated by the X-ray microbeam. Geant4 simulations proved that the additional peaks were due to optical photons generated in the barrier film coupled to the sensitive volume. The simulations also confirmed that the amplitude of the additional peak in comparison with the microbeam decreased for spectra with lower peak energies, as observed in the experimental data. The material packaging can be optimized during fabrication by solution processing onto a flexible substrate with a non-fluorescent barrier film. With these improvements, organic photodetectors show promising prospects as a cost-effective high spatial resolution tissue-equivalent flexible dosimeter for synchrotron radiation fields.


Asunto(s)
Radioterapia/instrumentación , Semiconductores , Fraccionamiento de la Dosis de Radiación , Diseño de Equipo , Dosímetros de Radiación , Dosificación Radioterapéutica , Sincrotrones , Rayos X
17.
J Pediatr Orthop ; 41(10): 604-609, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34419981

RESUMEN

INTRODUCTION: Femoral head avascular necrosis (AVN) affects between 10% and 41% of children with sickle cell disease (SCD), resulting in the development of proximal femoral deformity and residual hip pain in the majority of patients without treatment. There have been multiple adult studies published on the outcomes of core decompression with and without the use of bone marrow aspirate concentrate (BMAC) injection both in idiopathic and SCD-related AVN with promising results, however, few studies have reported on outcomes in skeletally immature patients. PURPOSE: This study sought to report on a single surgeon's outcomes for core decompression with BMAC injection in pediatric patients with AVN of the femoral head secondary to underlying SCD. METHODS: A single-center, retrospective review was performed for pediatric patients undergoing core decompression with BMAC injection for femoral head AVN in patients with SCD with a minimum of 12-month follow-up. Demographic, radiographic, and clinical variable were collected. Patients were subdivided based upon presence of open femoral physes at the time of surgery. Successful treatment was defined as the ability to return to activities without limitations. RESULTS: A total of 13 patients (average age 14.1±2.8 y, 84.6% male, 6 skeletally immature and 7 skeletally mature) with 18 affected extremities were identified. Open physes were present in 50% of operative extremities. Skeletally immature patient demonstrated reconstitution of the femoral head in 78% of cases and 89% demonstrated regression of at least 1 Steinberg grade and none had progression. Skeletally immature patients were significantly more likely to return to activities (100% vs. 55.6%, P=0.023) and achieve a final Tonnis grade <2 (89% vs. 44%, P=0.046). CONCLUSION: Core decompression appears to alter the natural history of AVN in skeletally immature patients with SCD. Skeletal immaturity was a positive prognostic factor for the ability to return to activities without pain and achieve a lower Tonnis grade at final follow-up.


Asunto(s)
Anemia de Células Falciformes , Necrosis de la Cabeza Femoral , Adolescente , Anemia de Células Falciformes/complicaciones , Médula Ósea/diagnóstico por imagen , Niño , Descompresión , Femenino , Cabeza Femoral/diagnóstico por imagen , Cabeza Femoral/cirugía , Necrosis de la Cabeza Femoral/diagnóstico por imagen , Necrosis de la Cabeza Femoral/etiología , Necrosis de la Cabeza Femoral/cirugía , Humanos , Masculino , Estudios Retrospectivos , Resultado del Tratamiento
18.
Artículo en Inglés | MEDLINE | ID: mdl-34123553

RESUMEN

BACKGROUND: In spine surgery, the halo fixator was initially utilized to stabilize cervical fusions in patients with poliomyelitis. More recently, the indications for halo fixation have evolved to include stabilization and definitive treatment for upper cervical spine injuries (Jefferson fractures, atlanto-occipital dissociations, odontoid fractures, etc.), treatment of atlantoaxial rotatory subluxation, stabilization of long cervical fusions, and preoperative traction. In the realm of pediatric spinal deformity, halo fixation has proved to be a valuable resource for severe or neglected spinal deformities. In this video article, we demonstrate the application of a halo fixator in a pediatric patient with severe scoliosis. DESCRIPTION: The procedure includes appropriate pin placement in the safe zones of the skull performed under either general anesthesia or local anesthesia. Pins are secured to a halo frame that is sized to be 2 cm larger than the circumference of the skull and are tightened according to age-specific torque guidelines. ALTERNATIVES: Alternative treatments vary from cervical spine immobilization to definitive surgical treatment in the spine, or even spinal osteotomies, depending on the underlying spinal pathology. RATIONALE: The halo fixator works by limiting motion of the cervical spine in flexion, extension, and axial rotation. The halo is also able to control and correct translational injuries of the cervical spine. In the setting of spinal deformity, the halo fixator can also be utilized to overcome the effects of gravity and lengthen the spine. EXPECTED OUTCOMES: For spinal deformities, the halo fixator can be expected to lengthen the spine and increase deformity flexibility prior to definitive surgical treatment in the spine or growth-friendly spinal instrumentation. IMPORTANT TIPS: Correct identification of safe zones for pin placement is vital to correct pin placement.For pediatric patients, it is important to obtain fixation with a minimum of 6 to 8 pins.Pins should be tightened with use of a torque-limiting wrench, up to no more than 1 in/lb (55.9 mm/kg) per year of age, up to a maximum of 8 in/lb (447.9 mm/kg).Applied traction should be a maximum of 50% of the body weight of the patient.Neurovascular examination is vital following application of weight.

19.
Nanomaterials (Basel) ; 11(5)2021 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-33946256

RESUMEN

This work reports the development of a highly sensitive pressure detector prepared by inkjet printing of electroactive organic semiconducting materials. The pressure sensing is achieved by incorporating a quantum tunnelling composite material composed of graphite nanoparticles in a rubber matrix into the multilayer nanostructure of a printed organic thin film transistor. This printed device was able to convert shock wave inputs rapidly and reproducibly into an inherently amplified electronic output signal. Variation of the organic ink material, solvents, and printing speeds were shown to modulate the multilayer nanostructure of the organic semiconducting and dielectric layers, enabling tuneable optimisation of the transistor response. The optimised printed device exhibits rapid switching from a non-conductive to a conductive state upon application of low pressures whilst operating at very low source-drain voltages (0-5 V), a feature that is often required in applications sensitive to stray electromagnetic signals but is not provided by conventional inorganic transistors and switches. The printed sensor also operates without the need for any gate voltage bias, further reducing the electronics required for operation. The printable low-voltage sensing and signalling system offers a route to simple low-cost assemblies for secure detection of stimuli in highly energetic systems including combustible or chemically sensitive materials.

20.
Jpn J Infect Dis ; 74(6): 511-516, 2021 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-33790066

RESUMEN

Neonatal pertussis can potentially cause severe complications and even death. Mothers have been most frequently identified as the source of neonatal pertussis. Approximately a dozen countries have implemented pertussis vaccination programs for pregnant women to protect neonates; however, in Japan, this has not been implemented. The aim of this questionnaire-based study was to ascertain the willingness of women to be vaccinated during pregnancy and the factors associated with willingness. The subjects were 977 pregnant women who visited either of the two selected hospitals for maternity health checks. Most of the women were in their first pregnancy (96%), and approximately half of them considered a physician to be the most reliable source of information about vaccination (481/977, 49%). "Willingness to receive pertussis vaccination" was significantly associated with the factors "no fear of receiving vaccination" (odds ratio [OR] = 3.10, 95% confidence interval [CI]: 2.21-4.34), "necessary to prevent pertussis" (OR = 8.70, 95% CI: 6.17-12.28), "effective in pregnancy" (OR = 5.46, 95% CI: 3.94-7.56), and "no concern about the side effects after vaccination" (OR = 3.03, 95% CI: 1.66-5.55). Pregnant women are likely to consider vaccination if they have a good understanding of the disease and its outcomes. Physicians are well positioned to improve knowledge and attitudes toward pertussis vaccination during pregnancy.


Asunto(s)
Vacunas contra Difteria, Tétanos y Tos Ferina Acelular/administración & dosificación , Transmisión de Enfermedad Infecciosa/prevención & control , Conocimientos, Actitudes y Práctica en Salud , Vacunas contra la Influenza , Complicaciones Infecciosas del Embarazo/prevención & control , Mujeres Embarazadas/psicología , Tos Ferina/prevención & control , Adulto , Vacunas contra Difteria, Tétanos y Tos Ferina Acelular/inmunología , Femenino , Humanos , Recién Nacido , Japón , Embarazo , Vacunación
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