Rural Hospital Closures: A Scoping Review of Studies Published Between 1990 and 2020.

Between 1990 and 2020, 334 rural hospitals closed in the United States, and since 2011 hospital closures have outnumbered new hospital openings. This scoping review evaluates peer-reviewed studies published since 1990 with a focus on rural hospital closures, synthesizing studies across six themes: 1) health care policy environment, 2) precursors to rural hospital closures, 3) economic impacts, 4) effects of rural hospital closures on access to care, 5) health and community impacts, and 6) definitions of rural hospitals and communities. In the 1990s, rural hospitals that closed were smaller, while rural hospitals that closed in the 2010s tended to have more beds. Many studies of the health impacts of rural hospital closures yielded null findings. However, these studies differed in their definitions of "rural hospital closure." Given the accelerated rate of hospital closures, more attention should be paid to hospitals that serve rural communities of color and low-income communities.

Adolescent Sleep Quality and Alcohol Use: An Initial Examination of the Serial Indirect Effects of Anxiety Symptoms and Coping Motives for Alcohol Use.

Background: Insufficient sleep and insomnia are associated with alcohol use as well as anxiety during adolescence and young adulthood. A negative reinforcement path to explain the association between sleep difficulties and alcohol misuse has been proposed. Within this pathway, it is speculated that while sober, insomnia and insufficient sleep lead to increased anxiety as well as anxiolytic responses to alcohol, thereby increasing the risk for both alcohol use and alcohol use problems. No work to date has examined the negative reinforcement path to alcohol use among adolescents who have consumed alcohol. Objectives: The current study aims to address this gap in the literature by examining if sleep quality is related to adolescent alcohol use problems and frequency through serial indirect effects of adolescent anxiety symptoms and coping motives for alcohol use. A total of 147 adolescents between the ages of 13 and 18 years (Mage = 16.31; SD = 0.96) from all geographic regions in the US were recruited using social media platforms (i.e., Facebook and Instagram). Participants who reported having tried alcohol at least once completed self-report measures to examine sleep quality, anxiety symptoms, alcohol use problems, alcohol use frequency, and coping motives for alcohol use. Results: Adolescent sleep quality was found to be associated with higher levels of both alcohol use problems and alcohol use frequency through the serial indirect effect of anxiety symptoms and coping motives for alcohol use. Conclusions: Overall, these findings represent a step towards understanding the complex relationship between sleep quality, alcohol, anxiety, and coping motives among adolescents.

Silicon-RosIndolizine fluorophores with shortwave infrared absorption and emission profiles enable in vivo fluorescence imaging.

In vivo fluorescence imaging in the shortwave infrared (SWIR, 1,000-1,700 nm) and extended SWIR (ESWIR, 1,700-2,700 nm) regions has tremendous potential for diagnostic imaging. Although image contrast has been shown to improve as longer wavelengths are accessed, the design and synthesis of organic fluorophores that emit in these regions is challenging. Here we synthesize a series of silicon-RosIndolizine (SiRos) fluorophores that exhibit peak emission wavelengths from 1,300-1,700 nm and emission onsets of 1,800-2,200 nm. We characterize the fluorophores photophysically (both steady-state and time-resolved), electrochemically and computationally using time-dependent density functional theory. Using two of the fluorophores (SiRos1300 and SiRos1550), we formulate nanoemulsions and use them for general systemic circulatory SWIR fluorescence imaging of the cardiovascular system in mice. These studies resulted in high-resolution SWIR images with well-defined vasculature visible throughout the entire circulatory system. This SiRos scaffold establishes design principles for generating long-wavelength emitting SWIR and ESWIR fluorophores.

Nonadiabatic Derivative Couplings through Multiple Franck-Condon Modes Dictate the Energy Gap Law for Near and Short-Wave Infrared Dye Molecules.

Near infrared (NIR, 700-1000 nm) and short-wave infrared (SWIR, 1000-2000 nm) dye molecules exhibit significant nonradiative decay rates from the first singlet excited state to the ground state. While these trends can be empirically explained by a simple energy gap law, detailed mechanisms of nearly universal behavior have remained unsettled for many cases. Theoretical and experimental results for two representative NIR/SWIR dye molecules reported here clarify the key mechanism for the observed energy gap law behavior. It is shown that the first derivative nonadiabatic coupling terms serve as major coupling pathways for nonadiabatic decay processes from the first excited singlet state to the ground state for these NIR and SWIR dye molecules and that vibrational modes other than the highest frequency modes also make significant contributions to the rate. This assessment is corroborated by further theoretical comparison with possible alternative mechanisms of intersystem crossing to triplet states and also by comparison with experimental data for deuterated molecules.

Deuteration of heptamethine cyanine dyes enhances their emission efficacy.

The design of bright short-wave infrared fluorophores remains a grand challenge. Here we investigate the impact of deuteration on the properties in a series of heptamethine dyes, the absorption of which spans near-infrared and SWIR regions. We demonstrate that it is a generally applicable strategy that leads to enhanced quantum yields of fluorescence, longer-lived singlet excited states and suppressed rates of non-radiative deactivation processes.

Barriers and facilitators to early-stage lung cancer care in the USA: a qualitative study.

PURPOSE: Improved outcomes in lung cancer treatment are seen in high-volume academic centers, making it important to understand barriers to accessing care at such institutions. Few qualitative studies examine the barriers and facilitators to early-stage lung cancer care at US academic institutions. METHODS: Adult patients with suspected or diagnosed early-stage non-small cell lung cancer presenting to a multidisciplinary lung cancer clinic at a US academic institution over a 6-month period beginning in 2019 were purposively sampled for semi-structured interviews. Semi-structured interviews were conducted and a qualitative content analysis was performed using the framework method. Themes relating to barriers and facilitators to lung cancer care were identified through iterative team-based coding. RESULTS: The 26 participants had a mean age of 62 years (SD: 8.4 years) and were majority female (62%), white (77%), and urban (85%). We identified 6 major themes: trust with providers and health systems are valued by patients; financial toxicity negatively influenced the diagnostic and treatment experience; social constraints magnified other barriers; patient self-advocacy as a facilitator of care access; provider advocacy could overcome other barriers; care coordination and good communication were important to patients. CONCLUSIONS: We have identified several barriers and facilitators to lung cancer care at an academic center in the US. These factors need to be addressed to improve quality of care among lung cancer patients. Further work will examine our findings in a community setting to understand if our findings are generalizable to patients who do not access a tertiary cancer care center.

A broad internalizing dimension accounts for the genetic associations between personality and individual internalizing disorders.

Much research has demonstrated that psychopathology can be described in terms of broad dimensions, representing liability for multiple psychiatric disorders. Broad spectra of psychopathology (e.g., internalizing and externalizing) are increasingly used as targets for research investigating the development, etiology, and course of psychopathology because they account for patterns of relatedness among disorders that were once presumed distinct. Thus, these spectra represent alluring targets due to their comprehensive and parsimonious nature. Nevertheless, little research has established the role of individual disorders over and above broad dimensions in the study of psychopathology. In the current study, we investigate whether there are unique etiological associations between individual internalizing disorders and personality traits after accounting for their etiological associations with a broad internalizing dimension. We used a community sample of twins (Npairs = 448) ages 4 to 19 to examine the etiological associations between internalizing psychopathology and Big Five personality dimensions. In terms of genetic covariation, a broad internalizing dimension was positively associated with neuroticism and negatively associated with extraversion, agreeableness, and conscientiousness. Moreover, internalizing accounted for most of the genetic variance shared between individual internalizing disorders and personality traits. Nevertheless, there were unique genetic associations between the following pairs of personality traits and disorders: neuroticism and social anxiety, extraversion and social anxiety, agreeableness and depression, and conscientiousness and compulsions. There was little evidence of environmental influences shared between internalizing and personality. In sum, a broad internalizing dimension adequately accounted for almost all of the etiologic covariation between internalizing disorders and personality, with several interesting exceptions. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Rural Medicare beneficiaries are increasingly likely to be admitted to urban hospitals.

OBJECTIVE: To determine whether rural Medicare FFS beneficiaries are more likely to be admitted to an urban hospital in 2018 than in 2010. DATA SOURCES: We combined data from the 2010 to 2018 Hospital Service Area File (HSAF) and the 2010-2017 American Hospital Association (AHA) survey. STUDY DESIGN: We conducted a fixed-effects negative-binomial regression to determine whether urban hospital admissions from rural ZIP codes were increasing over time. We also conducted an exploratory geographically weighted regression. DATA COLLECTION: We transformed the HSAF data into a ZIP code-level file with all rural ZIP codes. We defined rural as having a Rural-Urban Commuting Area (RUCA) code ≥4. A hospital's system affiliation status was incorporated from the AHA survey. PRINCIPAL FINDINGS: Controlling for distance to the nearest hospitals, an increase of 1 year was associated with a 2.0% increase (p < 0.001) in the number of admissions to urban hospitals from each rural ZIP code. New system affiliation of the nearest rural hospital was associated with an increase of 1.7% (p < 0.001). CONCLUSIONS: Even when controlling for distance to the nearest rural hospital (which reflects hospital closures), rural patients were increasingly likely to be admitted to an urban hospital.

An initial examination of the associations between appearance-related safety behaviors, socioemotional, and body dysmorphia symptoms during adolescence.

INTRODUCTION: Adolescence is characterized by the onset of a relatively specific set of socioemotional disorders (i.e., depression, generalized anxiety disorder, social anxiety disorder, and eating disorders) as well as body dysmorphia symptoms. Appearance-related concerns are a central feature of these disorders. Emerging evidence in adults suggests that appearance-related safety behaviors may play an instrumental role in the onset and maintenance of a number of disorders. To date, no work has examined appearance-related safety behaviors during adolescence. The present study examined the extent to which appearance-related safety behaviors may be associated with socioemotional and body dysmorphia symptoms during adolescence. METHODS: Adolescents between the ages of 13 and 17 years old (N = 387, Mage = 14.82 years, 31.3% identified as male, 47.0% identified as female, and 19.1% identified as nonbinary/third gender, 2.6% declined to report gender identity) completed measures assessing negative affect, anxiety-relevant safety behavior use, cognitive reappraisal, expressive suppression, appearance-related safety behaviors, body dysmorphia symptoms, and socioemotional symptoms. Structural Equation Modeling was used to test hypotheses. RESULTS: The results of this study suggest that appearance-related safety behaviors evidenced associations with latent factors corresponding to affective (i.e., depression, generalized anxiety disorder, social anxiety), eating disorders, and body dysmorphia symptoms after controlling for previously established vulnerability factors. CONCLUSIONS: These findings demonstrate that appearance-related safety behaviors may evidence transdiagnostic associations with socioemotional symptoms and body dysmorphia symptoms during adolescence.

A Preliminary Examination of the Interaction between Maternal Generalized Anxiety Disorder and Offspring Negative Affect in Relation to Maternal Worry about Offspring and Perceptions of Psychological Control.

Both maternal symptoms and adolescent offspring characteristics are associated with maladaptive parenting among families at risk for anxiety. One disorder that may be particularly associated with maladaptive parenting behaviors is generalized anxiety disorder (GAD). Previous work suggests that offspring negative affect (NA) is associated with different levels of maladaptive parenting behaviors among mothers with GAD. No work to date, however, has examined the association between offspring reported NA, maternal GAD, and maternal worry about offspring or maternal perceptions of psychological control (PC) among mothers of adolescents. Sixty-five mothers who were elevated in anxious arousal and their adolescent offspring between the ages of 12 and 16 years old (n = 65, 55% male, Mage = 13.89) reported on parenting (mother report), NA (offspring report), and GAD symptoms (assessed via structured clinical interview), and maternal anxiety sensitivity (AS) symptoms. Study results indicated that maternal GAD status interacted with offspring NA in relation to maternal reported use of PC and worry about offspring. Specifically, offspring NA was positively related to PC for mothers without GAD, but not for mothers with GAD. Further, for mothers with GAD, offspring NA was negatively related to worry about offspring, but this relation did not persist for mothers without GAD. Maternal AS was related to overall higher levels of worry about offspring and PC. Mothers with GAD report using higher levels of maladaptive parenting when offspring report lower levels of NA, and lower levels when offspring report high NA. This pattern was specific to maternal GAD (c.f. anxiety sensitivity).

Barriers to HIV and Hepatitis C care for people who inject drugs in Colombia.

People who inject drugs (PWIDs) are a key population targeted in global efforts to increase HIV and Hepatitis C virus (HCV) diagnosis, linkage to care, and treatment retention. Colombia has experienced a significant increase in the incidence of HIV and HCV attributed to the alarming rise in injection drug use. The primary aim of this study was to identify factors influencing access to HIV and HCV care among PWIDs. Survey domains consisted of (1) sociodemographic characteristics; (2) history of HIV-HCV testing and infection status; (3) the 13-item questionnaire developed by Awad and colleagues to explore barriers to HIV and HCV testing, (4) the Barriers to Medical Care questionnaire; and (5) the Risk Assessment Battery. A total of 171 subjects completed the survey. A high proportion of participants reported past year testing for HIV (87%) and HCV (72.8%). However, most respondents elicited numerous barriers to obtaining information, referrals, and insurance coverage for accessing HIV and/or HCV care. Further studies are needed to identify scalable public health measures to overcome these barriers.

Establishing design principles for emissive organic SWIR chromophores from energy gap laws.

Rational design of bright near and shortwave infrared (NIR: 700-1000 SWIR: 1000- 2000 nm) emitters remains an open question with applications spanning imaging and photonics. Combining experiment and theory, we derive an energy gap quantum yield master equation (EQME), describing the fundamental limits in SWIR quantum yields (ϕ F ) for organic chromophores. Evaluating the photophysics of 21 polymethine NIR/SWIR chromophores to parameterize the EQME, we explain the precipitous decline of ϕ F past 900 nm through decreasing radiative rates and increasing nonradiative losses via high frequency vibrations relating to the energy gap. Using the EQME we develop an energy gap independent ϕ F NIR/SWIR chromophore comparison metric. We show electron donating character on polymethine heterocycles results in relative increases in radiative efficiency obscured by a simultaneous redshift. Finally, the EQME yields rational chromophore design insights shown by how deuteration (backed by our experimental results) or molecular aggregation increases SWIR ϕ F .

Complexity of Medication Regimens for Children With Neurological Impairment.

Importance: Parents of children with severe neurological impairment (SNI) manage complex medication regimens (CMRs) at home, and clinicians can help support parents and simplify CMRs. Objective: To measure the complexity and potentially modifiable aspects of CMRs using the Medication Regimen Complexity Index (MRCI) and to examine the association between MRCI scores and subsequent acute visits. Design, Setting, and Participants: This cross-sectional study was conducted between April 1, 2019, and December 31, 2020, at a single-center, large, hospital-based, complex care clinic. Participants were children with SNI aged 1 to 18 years and 5 or more prescribed medications. Exposure: Home medication regimen complexity was assessed using MRCI scores. The total MRCI score is composed of 3 subscores (dosage form, dose frequency, and specialized instructions). Main Outcomes and Measures: Patient-level counts of subscore characteristics and additional safety variables (total doses per day, high-alert medications, and potential drug-drug interactions) were analyzed by MRCI score groups (low, medium, and high score tertiles). Associations between MRCI score groups and acute visits were tested using Poisson regression, adjusted for age, complex chronic conditions, and recent health care use. Results: Of 123 patients, 73 (59.3%) were male with a median (interquartile range [IQR]) age of 9 (5-13) years. The median (IQR) MRCI scores were 46 (35-61 [range, 8-139]) overall, 29 (24-35) for the low MRCI group, 46 (42-50) for the medium MRCI group, and 69 (61-78) for the high MRCI group. The median (IQR) counts for the subscores were 6 (4-7) dosage forms per patient, 7 (5-9) dose frequencies per patient, and 5 (4-8) instructions per patient, with counts increasing significantly across higher MRCI groups. Similar trends occurred for total daily doses (median [IQR], 31 [20-45] doses), high-alert medications (median [IQR], 3 [1-5] medications), and potential drug-drug interactions (median [IQR], 3 [0-6] interactions). Incidence rate ratios of 30-day acute visits were 1.26 times greater (95% CI, 0.57-2.78) in the medium MRCI group vs the low MRCI group and 2.42 times greater (95% CI, 1.10-5.35) in the high MRCI group vs the low MRCI group. Conclusions and Relevance: Higher MRCI scores were associated with multiple dose frequencies, complicated by different dosage forms and instructions, and associated with subsequent acute visits. These findings suggest that clinical interventions to manage CMRs could target various aspects of these regimens, such as the simplification of dosing schedules.

Cigarette use, anxiety, and insomnia from adolescence to early adulthood: A longitudinal indirect effects test.

BACKGROUND: Cigarette use during adolescence has been linked to increased risk for insomnia symptoms, but limited work has examined factors that may account for this association. Adolescent cigarette use and anxiety symptoms characterized by physiological hyperarousal evidence bidirectional associations, as do anxiety symptoms and insomnia symptoms. This suggests that adolescent cigarette use, anxiety symptoms characterized by physiological hyperarousal, and insomnia symptoms may increase and maintain one another. The current study tests physiological hyperarousal anxiety symptoms as a potential indirect effect in the cigarette-insomnia symptoms link across adolescence and young adulthood. METHODS: We examined data from adolescents and young adults from Waves 1, 2, 3 and 4 of the National Longitudinal Study of Adolescent to Adult Health (N = 2,432 with full data). Insomnia symptoms were assessed at baseline (ages 12-16 years), 1 year later (13-17 years), and 14 years after baseline (26 - 30 years) among a nationally representative sample of adolescents. Cigarette use was assessed at baseline, 1 year later, 6 years after baseline, and 14 years after baseline. Anxiety symptoms were assessed at baseline and 1 year later. RESULTS: Structural equation models indicated that anxiety symptoms exerted an indirect effect on the longitudinal associations between adolescent cigarette use and adult insomnia symptoms. Anxiety symptoms and cigarette use evidenced bidirectional associations during adolescence. CONCLUSIONS: These results suggest that increases in anxiety symptoms characterized by physiological hyperarousal may be one mechanism whereby cigarette use during adolescence is associated with increased insomnia symptoms during early adulthood. Prevention efforts aimed at reducing cigarette use during adolescence may have long term additional benefits for anxiety symptoms and insomnia symptoms.

Primary Care Practices in Western North Carolina: Adaptation to the COVID-19 Pandemic and Ongoing Challenges.

Introduction: The COVID-19 pandemic has created unique challenges for primary care practices while also highlighting their importance in the pandemic response. To understand primary care practice needs, a survey was conducted of practices in Western North Carolina. Methods: Phase 2 of a primary care needs assessment was administered to 63 practices in Western North Carolina over the course of six weeks, from July 23 to August 31, 2021. Results: Most practices were operating with normal hours, though some still operated with reduced hours. Many practices reported insufficient personal protective equipment (PPE) supplies. While most practices provided at least some care via telehealth, practices cited different barriers to providing telehealth, with patient technology challenges being the most frequently cited. Discussion: Practices have adapted to the restrictions of the pandemic, but many are still vulnerable, and the patients they serve may face reduced access to care due to practice limitations or barriers to telehealth. Practices play a critical role in providing care to patients throughout the pandemic and continue to assist in pandemic response by providing COVID-19 testing and other services. Conclusion: Primary care practices in Western North Carolina continue to provide care to patients and support the overall pandemic response. The pandemic has highlighted the need to include primary care in emergency response efforts. Ongoing work will allow North Carolina to reach practices more effectively in future crises via the newly created NC Responds system, which allows primary care practices to be contacted in the event of a public health emergency.

Interleukin 33 Triggers Early Eosinophil-Dependent Events Leading to Metaplasia in a Chronic Model of Gastritis-Prone Mice.

BACKGROUND & AIMS: Interleukin (IL)33/IL1F11 is an important mediator for the development of type 2 T-helper cell (Th2)-driven inflammatory disorders and has also been implicated in the pathogenesis of gastrointestinal (GI)-related cancers, including gastric carcinoma. We therefore sought to mechanistically determine IL33's potential role as a critical factor linking chronic inflammation and gastric carcinogenesis using gastritis-prone SAMP1/YitFc (SAMP) mice. METHODS: SAMP and (parental control) AKR mice were assessed for baseline gastritis and progression to metaplasia. Expression/localization of IL33 and its receptor, ST2/IL1R4, were characterized in corpus tissues, and activation and neutralization studies were both performed targeting the IL33/ST2 axis. Dissection of immune pathways leading to metaplasia was evaluated, including eosinophil depletion studies using anti-IL5/anti-CCR3 treatment. RESULTS: Progressive gastritis and, ultimately, intestinalized spasmolytic polypeptide-expressing metaplasia (SPEM) was detected in SAMP stomachs, which was absent in AKR but could be moderately induced with exogenous, recombinant IL33. Robust peripheral (bone marrow) expansion of eosinophils and local recruitment of both eosinophils and IL33-expressing M2 macrophages into corpus tissues were evident in SAMP. Interestingly, IL33 blockade did not affect bone marrow-derived expansion and local infiltration of eosinophils, but markedly decreased M2 macrophages and SPEM features, while eosinophil depletion caused a significant reduction in both local IL33-producing M2 macrophages and SPEM in SAMP. CONCLUSIONS: IL33 promotes metaplasia and the sequelae of eosinophil-dependent downstream infiltration of IL33-producing M2 macrophages leading to intestinalized SPEM in SAMP, suggesting that IL33 represents a critical link between chronic gastritis and intestinalizing metaplasia that may serve as a potential therapeutic target for preneoplastic conditions of the GI tract.

Socioeconomic Status and Determinants of Pediatric Antibiotic Use.

Introduction. Evidence suggests that early-life antibiotic use can alter gut microbiome, predisposing children to obesity. The obesity epidemic has a disproportionate effect on individuals from lower socioeconomic status (SES). Thus, this study aims to explore the link between SES and antibiotic use. Design. We performed a retrospective cohort study of all babies born at and receiving 2 or more outpatient visits at a large, suburban health system in Illinois (United States) between 2007 and 2017. We collected data on zip code as a proxy for SES and antibiotic use in the first year of life. We also obtained comorbid diagnosis codes, race/ethnicity, gender, and number of inpatient, outpatient, and emergency department visits. Results. A total of 7224 patients met our study criteria. Children from low-poverty areas received a lifetime average of 4.28 prescriptions, while those from high-poverty neighborhoods received an average of 3.31 prescriptions. This was statistically significant in our unadjusted analysis but not after adjusting for covariates. Children from high-poverty areas were significantly more likely to receive more antibiotics at 48 hours, 1 week, and 1 month of life in our unadjusted analysis, but not after adjusting for covariates. In our unadjusted and adjusted analyses, children from high-poverty areas were significantly more likely to have received antibiotics at 1 week of life. Conclusion. The relationship between SES and antibiotic use warrants further investigation to help elucidate possible causes of the disproportionate impact obesity has in low-income communities.

The interaction between sleep disturbances and anxiety sensitivity in relation to adolescent anger responses to parent adolescent conflict.

INTRODUCTION: Sleep disturbances are common among adolescents and are associated with elevated anxiety, and difficulties managing affect. Familial conflict is associated with both anxiety sensitivity and adolescent sleep disturbances. No work to date has examined how adolescent sleep disturbances may interact with anxiety sensitivity in relation to adolescent affective responding to parent-adolescent conflict. The current study was designed to address this gap in the literature by examining how adolescent sleep disturbances, anxiety sensitivity, conflict elicited anger, and conflict avoidance are associated. METHOD: Seventy-two American adolescents (n = 39 males) between the ages of 12 and 16 years (Mage = 13.84, SD = 1.38) completed a baseline assessment as well as a well-validated mother-adolescent laboratory-based conflict task. RESULTS: For youth low in anxiety sensitivity, greater sleep disturbance related positively to conflict-elicited anger, which in turn predicted higher conflict avoidance. In contrast, this indirect effect was not significant for adolescents relatively higher in anxiety sensitivity. Instead, for these adolescents, increased sleep disturbances were associated with lower levels of conflict elicited anger. CONCLUSIONS: Results suggest that the effects of sleep disturbances on conflict elicited anger may vary as a function of adolescent anxiety vulnerability. These findings highlight the importance of considering the unique effects of sleep disturbances on adolescent affect as a function of adolescent anxiety vulnerability.

Mercury Chalcogenide Nanoplatelet-Quantum Dot Heterostructures as a New Class of Continuously Tunable Bright Shortwave Infrared Emitters.

Despite broad applications in imaging, energy conversion, and telecommunications, few nanoscale moieties emit light efficiently in the shortwave infrared (SWIR, 1000-2000 nm or 1.24-0.62 eV). We report quantum-confined mercury chalcogenide (HgX, where X = Se or Te) nanoplatelets (NPLs) can be induced to emit bright (QY > 30%) and tunable (900-1500+ nm) infrared emission from attached quantum dot (QD) "defect" states. We demonstrate near unity energy transfer from NPL to these QDs, which completely quench NPL emission and emit with a high QY through the SWIR. This QD defect emission is kinetically tunable, enabling controlled midgap emission from NPLs. Spectrally resolved photoluminescence demonstrates energy-dependent lifetimes, with radiative rates 10-20 times faster than those of their PbX analogues in the same spectral window. Coupled with their high quantum yield, midgap emission HgX dots on HgX NPLs provide a potential platform for novel optoelectronics in the SWIR.

Decay-Associated Fourier Spectroscopy: Visible to Shortwave Infrared Time-Resolved Photoluminescence Spectra.

We describe and implement an interferometric approach to decay-associated photoluminescence spectroscopy, which we term decay-associated Fourier spectroscopy (DAFS). In DAFS, the emitted photon stream from a substrate passes through a variable path length Mach-Zehnder interferometer prior to detection and timing. The interferometer encodes spectral information in the intensity measured at each detector enabling simultaneous spectral and temporal resolution. We detail several advantages of DAFS, including wavelength-range insensitivity, drift-noise cancellation, and optical mode retention. DAFS allows us to direct the photon stream into an optical fiber, enabling the implementation of superconducting nanowire single photon detectors for energy-resolved spectroscopy in the shortwave infrared spectral window (λ = 1-2 µm). We demonstrate the broad applicability of DAFS, in both the visible and shortwave infrared, using two Förster resonance energy transfer pairs: a pair operating with conventional visible wavelengths and a pair showing concurrent acquisition in the visible and the shortwave infrared regime.