Fast detection of liver fibrosis with collagen-binding single-nanometer iron oxide nanoparticles via T1-weighted MRI.

SNIO-CBP, a single-nanometer iron oxide (SNIO) nanoparticle functionalized with a type I collagen-binding peptide (CBP), was developed as a T1-weighted MRI contrast agent with only endogenous elements for fast and noninvasive detection of liver fibrosis. SNIO-CBP exhibits 6.7-fold higher relaxivity compared to a molecular gadolinium-based collagen-binding contrast agent CM-101 on a per CBP basis at 4.7 T. Unlike most iron oxide nanoparticles, SNIO-CBP exhibits fast elimination from the bloodstream with a 5.7 min half-life, high renal clearance, and low, transient liver enhancement in healthy mice. We show that a dose of SNIO-CBP that is 2.5-fold lower than that for CM-101 has comparable imaging efficacy in rapid (within 15 min following intravenous injection) detection of hepatotoxin-induced liver fibrosis using T1-weighted MRI in a carbon tetrachloride-induced mouse liver injury model. We further demonstrate the applicability of SNIO-CBP in detecting liver fibrosis in choline-deficient L-amino acid-defined high-fat diet mouse model of nonalcoholic steatohepatitis. These results provide a platform with potential for the development of high relaxivity, gadolinium-free molecular MRI probes for characterizing chronic liver disease.

Computationally Guided Ligand Discovery from Compound Libraries and Discovery of a New Class of Ligands for Ni-Catalyzed Cross-Electrophile Coupling of Challenging Quinoline Halides.

Although screening technology has heavily impacted the fields of metal catalysis and drug discovery, its application to the discovery of new catalyst classes has been limited. The diversity of on- and off-cycle pathways, combined with incomplete mechanistic understanding, means that screens of potential new ligands have thus far been guided by intuitive analysis of the metal binding potential. This has resulted in the discovery of new classes of ligands, but the low hit rates have limited the use of this strategy because large screens require considerable cost and effort. Here, we demonstrate a method to identify promising screening directions via simple and scalable computational and linear regression tools that leads to a substantial improvement in hit rate, enabling the use of smaller screens to find new ligands. The application of this approach to a particular example of Ni-catalyzed cross-electrophile coupling of aryl halides with alkyl halides revealed a previously overlooked trend: reactions with more electron-poor amidine ligands result in a higher yield. Focused screens utilizing this trend were more successful than serendipity-based screening and led to the discovery of two new types of ligands, pyridyl oxadiazoles and pyridyl oximes. These ligands are especially effective for couplings of bromo- and chloroquinolines and isoquinolines, where they are now the state of the art. The simplicity of these models with parameters derived from metal-free ligand structures should make this approach scalable and widely accessible.

Computational Methods Enable the Prediction of Improved Catalysts for Nickel-Catalyzed Cross-Electrophile Coupling.

Cross-electrophile coupling has emerged as an attractive and efficient method for the synthesis of C(sp2)-C(sp3) bonds. These reactions are most often catalyzed by nickel complexes of nitrogenous ligands, especially 2,2'-bipyridines. Precise prediction, selection, and design of optimal ligands remains challenging, despite significant increases in reaction scope and mechanistic understanding. Molecular parameterization and statistical modeling provide a path to the development of improved bipyridine ligands that will enhance the selectivity of existing reactions and broaden the scope of electrophiles that can be coupled. Herein, we describe the generation of a computational ligand library, correlation of observed reaction outcomes with features of the ligands, and the in silico design of improved bipyridine ligands for Ni-catalyzed cross-electrophile coupling. The new nitrogen-substituted ligands display a 5-fold increase in selectivity for product formation versus homodimerization when compared to the current state of the art. This increase in selectivity and yield was general for several cross-electrophile couplings, including the challenging coupling of an aryl chloride with an N-alkylpyridinium salt.

Self-reported knowledge of tetrahydrocannabinol and cannabidiol concentration in cannabis products among cancer patients and survivors.

PURPOSE: Cannabis use may introduce risks and/or benefits among people living with cancer, depending on product type, composition, and nature of its use. Patient knowledge of tetrahydrocannabinol (THC) or cannabidiol (CBD) concentration could provide information for providers about cannabis use during and after treatment that may aide in risk and benefit assessments. This study aimed to examine knowledge of THC or CBD concentration among patients living with cancer who consume cannabis, and factors associated with knowledge of cannabinoid concentrations. METHODS: People living with cancer who consumed cannabis since their diagnosis (n = 343) completed an anonymous, mixed-mode survey. Questions assessed usual mode of delivery (MOD), knowledge of THC/CBD concentration, and how source of acquisition, current cannabis use, and source of instruction are associated with knowledge of THC/CBD concentration. Chi-square and separate binary logistic regression analyses were examined and weighted to reflect the Roswell Park patient population. RESULTS: Less than 20% of people living with cancer had knowledge of THC and CBD concentration for the cannabis products they consumed across all MOD (smoking- combustible products, vaping- vaporized products (e-cigarettes), edibles-eating or drinking it, and oral- taking by mouth (pills)). Source of acquisition (smoking-AOR:4.6, p < 0.01, vaping-AOR:5.8, p < 0.00, edibles-AOR:2.6, p < 0.04), current cannabis use (edibles-AOR:5.4, p < 0.01, vaping-AOR: 11.2, p < 0.00, and oral-AOR:9.3, p < 0.00), and source of instruction (vaping only AOR:4.2, p < 0.05) were found to be variables associated with higher knowledge of THC concentration. CONCLUSION: Self-reported knowledge of THC and CBD concentration statistically differed according to MOD, source of acquisition, source of instruction, and current cannabis use.

Single-nanometer iron oxide nanoparticles as tissue-permeable MRI contrast agents.

Magnetic nanoparticles are robust contrast agents for MRI and often produce particularly strong signal changes per particle. Leveraging these effects to probe cellular- and molecular-level phenomena in tissue can, however, be hindered by the large sizes of typical nanoparticle contrast agents. To address this limitation, we introduce single-nanometer iron oxide (SNIO) particles that exhibit superparamagnetic properties in conjunction with hydrodynamic diameters comparable to small, highly diffusible imaging agents. These particles efficiently brighten the signal in T1-weighted MRI, producing per-molecule longitudinal relaxation enhancements over 10 times greater than conventional gadolinium-based contrast agents. We show that SNIOs permeate biological tissue effectively following injection into brain parenchyma or cerebrospinal fluid. We also demonstrate that SNIOs readily enter the brain following ultrasound-induced blood-brain barrier disruption, emulating the performance of a gadolinium agent and providing a basis for future biomedical applications. These results thus demonstrate a platform for MRI probe development that combines advantages of small-molecule imaging agents with the potency of nanoscale materials.

Metal-Free Electrochemical Reduction of Disulfides in an Undivided Cell under Mass Transfer Control.

Electroorganic synthesis is generally considered to be a green alternative to conventional redox reactions. Electrochemical reductions, however, are less advantageous in terms of sustainability, as sacrificial metal anodes are often employed. Divided cell operation avoids contact of the reduction products with the anode and allows for convenient solvent oxidation, enabling metal free greener electrochemical reductions. However, the ion exchange membranes required for divided cell operation on a commercial scale are not amenable to organic solvents, which hinders their applicability. Herein, we demonstrate that electrochemical reduction of oxidatively sensitive compounds can be carried out in an undivided cell without sacrificial metal anodes by controlling the mass transport to a small surface area electrode. The concept is showcased by an electrochemical method for the reductive cleavage of aryl disulfides. Fine tuning of the electrode surface area and current density has enabled the preparation of a wide variety of thiols without formation of any oxidation side products. This strategy is anticipated to encourage further research on greener, metal free electrochemical reductions.

COMBINED HAMARTOMA OF THE RETINA AND RETINAL PIGMENT EPITHELIUM AT PEDIATRIC AGE: Surgical Versus Conservative Approach.

PURPOSE: To report outcomes of pediatric patients with combined hamartoma of the retina and the retina pigment epithelium followed up conservatively or after pars plana vitrectomy. METHODS: This retrospective multicenter study included 62 eyes of 59 pediatric patients with combined hamartoma of the retina and the retina pigment epithelium from 13 different international centers with an average age of 7.7 ± 4.7 (0.3-17) years at the time of the diagnosis and having undergone pars plana vitrectomy or followed conservatively. At baseline and each visit, visual acuity values, optical coherence tomography for features and central foveal thickness, and tumor location were noted. Lesions were called as Zone 1, if it involves the macular and peripapillary areas, and the others were called as Zone 2 lesions. RESULTS: Twenty-one eyes of 20 patients in the intervention group and 41 eyes of 39 patients in the conservative group were followed for a mean of 36.2 ± 40.4 (6-182) months. Best-corrected visual acuity improved in 11 (68.8%) of 16 eyes in the intervention group and 4 (12.9%) of 31 eyes in the conservative group ( P < 0.001). The mean central foveal thickness decreased from 602.0 ± 164.9 µ m to 451.2 ± 184.3 µ m in the intervention group, while it increased from 709.5 ± 344.2 µ m to 791.0 ± 452.1 µ m in Zone 1 eyes of the conservative group. Posterior location of tumor, irregular configuration of the foveal contour and ellipsoid Zone defect in optical coherence tomography, subretinal exudate and prominent vascular tortuosity were associated with poor visual acuity. CONCLUSION: Vitreoretinal surgery is safe and effective in improving vision and reducing retinal distortion in Zone 1 combined hamartoma of the retina and the retina pigment epithelium in children.

Galunisertib plus neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer: a single-arm, phase 2 trial.

BACKGROUND: TGF-ß is an immunosuppressive cytokine that is upregulated in colorectal cancer. TGF-ß blockade improved response to chemoradiotherapy in preclinical models of colorectal adenocarcinoma. We aimed to test the hypothesis that adding the TGF-ß type I receptor kinase inhibitor galunisertib to neoadjuvant chemoradiotherapy would improve pathological complete response rates in patients with locally advanced rectal cancer. METHODS: This was an investigator-initiated, single-arm, phase 2 study done in two medical centres in Portland (OR, USA). Eligible patients had previously untreated, locally advanced, rectal adenocarcinoma, stage IIA-IIIC or IV as per the American Joint Committee on Cancer; Eastern Cooperative Oncology Group status 0-2; and were aged 18 years or older. Participants completed two 14-day courses of oral galunisertib 150 mg twice daily, before and during fluorouracil-based chemoradiotherapy (intravenous fluorouracil 225 mg/m2 over 24 h daily 7 days per week during radiotherapy or oral capecitabine 825 mg/m2 twice per day 5 days per week during radiotherapy; radiotherapy consisted of 50·4-54·0 Gy in 28-30 fractions). 5-9 weeks later, patients underwent response assessment. Patients with a complete response could opt for non-operative management and proceed to modified FOLFOX6 (intravenous leucovorin 400 mg/m2 on day 1, intravenous fluorouracil 400 mg/m2 on day 1 then 2400 mg/m2 over 46 h, and intravenous oxaliplatin 85 mg/m2 on day 1 delivered every 2 weeks for eight cycles) or CAPEOX (intravenous oxaliplatin 130 mg/m2 on day 1 and oral capecitabine 1000 mg/m2 twice daily for 14 days every 3 weeks for four cycles). Patients with less than complete response underwent surgical resection. The primary endpoint was complete response rate, which was a composite of pathological complete response in patients who proceeded to surgery, or clinical complete response maintained at 1 year after last therapy in patients with non-operative management. Safety was a coprimary endpoint. Both endpoints were assessed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02688712, and is active but not recruiting. FINDINGS: Between Oct 19, 2016, and Aug 31, 2020, 38 participants were enrolled. 25 (71%) of the 35 patients who completed chemoradiotherapy proceeded to total mesorectal excision surgery, five (20%) of whom had pathological complete responses. Ten (29%) patients had non-operative management, three (30%) of whom ultimately chose to have total mesorectal excision. Two (67%) of those three patients had pathological complete responses. Of the remaining seven patients in the non-operative management group, five (71%) had clinical complete responses at 1 year after their last modified FOLFOX6 infusion. In total, 12 (32% [one-sided 95% CI ≥19%]) of 38 patients had a complete response. Common grade 3 adverse events during treatment included diarrhoea in six (16%) of 38 patients, and haematological toxicity in seven (18%) patients. Two (5%) patients had grade 4 adverse events, one related to chemoradiotherapy-induced diarrhoea and dehydration, and the other an intraoperative ischaemic event. No treatment-related deaths occurred. INTERPRETATION: The addition of galunisertib to neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer improved the complete response rate to 32%, was well tolerated, and warrants further assessment in randomised trials. FUNDING: Eli Lilly via ExIST program, The Providence Foundation.

Caregiver role strain in caring for vulnerable persons living with HIV: correlates of caregiver and care recipient reports.

Informal care of family and friends is important for the health and well-being of disadvantaged persons living with HIV (PLWH). Caregiver role strain may threaten the function and continuity of their main relationships and their health impacts. Data were from a disadvantaged, primarily African American, sample of PLWH care recipients. Caregiver role strain was operationalized as a latent factor measured by variables including PLWH's perceptions of their caregiver not wanting or complaining about helping them or wanting a break. We found that greater caregiver role strain was associated with higher levels of HIV-related stigma and depressive symptoms. Lower role strain was associated with more collaborative problem solving and shared medical treatment decision-making. Caregiver role strain was linked to disadvantaged PLWHs' worse stigma and mental health; collaborative engagement in care and coping assistance were protective of role strain. Caregiving relationship-focused research and interventions are needed for resourcing and sustaining disadvantaged African American communities' caregiving and health.

Lymphatic cells do not functionally integrate into 3D organotypic brain slice cultures, but aggregate around penetrating blood vessels.

Brain slice culture (BSC) is a well-known three-dimensional model of the brain. In this study, we use organotypic slices for studying neuro-lymphatic physiology, to directly test the longstanding assumption that the brain is not a hospitable milieu for typical lymphatic vessels. An additional objective is to model fluid egress through brain perivascular space systems and to visualize potential cellular interactions among cells in the leptomeninges including alterations of cellular geometry and number of processes. Immortalized lymphatic rat cell lines were used to seed organotypic brain slices. The brain slice model was characterized by monitoring morphologies, growth rates, degree of apoptosis, and transport properties of brain slices with or without a lymphatic component. The model was then challenged with fibroblast co-cultures, as a control cell that is not normally found in the brain. Immortalized lymphatic cells penetrated the brain slices within 2-4 days. Typical cell morphology is spindly with bipolar and tripolar forms well represented. Significantly more indigo carmine marker passed through lymphatic seeded BSCs compared to arachnoid BSCs. Significantly more indigo carmine passed through brain slices co-cultured with fibroblast compared to lymphatic and arachnoid BSCs alone. We have developed an organotypic model in which lymphatic cells are able to interact with parenchymal cells in the cerebrum. Their presence appears to alter the small molecule transport ability of whole-brain slices. Lymphatic cells decreased dye transport in BSCs, possibly by altering the perivascular space. Given their direct contact with the CSF, they may affect convectional and diffusional processes. Our model shows that a decrease in lymphatic cell growth may reduce the brain slice's transport capabilities.

Hydroxychloroquine in the treatment of outpatients with mildly symptomatic COVID-19: a multi-center observational study.

BACKGROUND: Hydroxychloroquine has not been associated with improved survival among hospitalized COVID-19 patients in the majority of observational studies and similarly was not identified as an effective prophylaxis following exposure in a prospective randomized trial. We aimed to explore the role of hydroxychloroquine therapy in mildly symptomatic patients diagnosed in the outpatient setting. METHODS: We examined the association between outpatient hydroxychloroquine exposure and the subsequent progression of disease among mildly symptomatic non-hospitalized patients with documented SARS-CoV-2 infection. The primary outcome assessed was requirement of hospitalization. Data was obtained from a retrospective review of electronic health records within a New Jersey USA multi-hospital network. We compared outcomes in patients who received hydroxychloroquine with those who did not applying a multivariable logistic model with propensity matching. RESULTS: Among 1274 outpatients with documented SARS-CoV-2 infection 7.6% were prescribed hydroxychloroquine. In a 1067 patient propensity matched cohort, 21.6% with outpatient exposure to hydroxychloroquine were hospitalized, and 31.4% without exposure were hospitalized. In the primary multivariable logistic regression analysis with propensity matching there was an association between exposure to hydroxychloroquine and a decreased rate of hospitalization from COVID-19 (OR 0.53; 95% CI, 0.29, 0.95). Sensitivity analyses revealed similar associations. QTc prolongation events occurred in 2% of patients prescribed hydroxychloroquine with no reported arrhythmia events among those with data available. CONCLUSIONS: In this retrospective observational study of SARS-CoV-2 infected non-hospitalized patients hydroxychloroquine exposure was associated with a decreased rate of subsequent hospitalization. Additional exploration of hydroxychloroquine in this mildly symptomatic outpatient population is warranted.

A digital tool for prevention and management of cold weather injuries-Cold Weather Ensemble Decision Aid (CoWEDA).

This paper describes a Cold Weather Ensemble Decision Aid (CoWEDA) that provides guidance for cold weather injury prevention, mission planning, and clothing selection. CoWEDA incorporates current science from the disciplines of physiology, meteorology, clothing, and computer modeling. The thermal performance of a cold weather ensemble is defined by endurance times, which are the time intervals from initial exposure until the safety limits are reached. These safety limits correspond to conservative temperature thresholds that provide a warning of the approaching onset of frostbite and/or hypothermia. A validated six-cylinder thermoregulatory model is used to predict human thermal responses to cold while wearing different ensembles. The performance metrics, model, and a database of clothing properties were integrated into a user-friendly software application. CoWEDA is the first tool that allows users to build their own ensembles from the clothing menu (i.e., jackets, footwear, and accessories) for each body region (i.e., head, torso, lower body, hands, feet) and view their selections in the context of physiological strain and the operational consequences. Comparison of predicted values to skin and core temperatures, measured during 17 cold exposures ranging from 0 to -40°C, indicated that the accuracy of CoWEDA prediction is acceptable, and most predictions are within measured mean ± SD. CoWEDA predicts the risk of frostbite and hypothermia and ensures that a selected clothing ensemble is appropriate for expected weather conditions and activities. CoWEDA represents a significant enhancement of required clothing insulation (IREQ, ISO 11079) and wind chill index-based guidance for cold weather safety and survival.

The Feasibility of Collecting Longitudinal Cardiovascular and Fitness Outcomes From a Neighborhood Park-Based Fitness Program in Ethnically Diverse Older Adults: A Proof-of-Concept Study.

This proof-of-concept study examined feasibility of assessing longitudinal changes in body mass index, strength, mobility, and cardiovascular health outcomes in older, racial/ethnic minority adults participating in a park-based physical activity program. Study feasibility was based on follow-through data collection procedures and ability to manage and implement data collection, enrollment, and repeated measures data collection in older adults (≥50 years; n = 380; 45% Hispanic, 41% non-Hispanic Black) over a 28-month period. Mixed models were developed to estimate the effects of program participation over time on participant cardiovascular and fitness outcomes and across poverty and age subgroups. Model estimates adjusted for individual-level sociodemographics showed improvements across each 4 month time point in arm strength (0.55 arm curl; 95% confidence interval [0.33, 0.77]) and systolic (-0.68 mmHg; 95% confidence interval [-1.22, -0.13]) and diastolic (-0.47 mmHg; 95% confidence interval [-0.79, -0.16]) blood pressure. An Age × Poverty interaction found greater improvements in systolic and diastolic blood pressure among younger participants living in low poverty (vs. older in higher poverty). Study of the longitudinal association between fitness class participation and health outcomes was feasible in park-based settings.

Promoting healthy trajectories for urban middle school youth through county-funded, parks-based after-school programming.

Ongoing pressure for public schools to prioritize academics has increased attention on after-school settings as a critical space for social-emotional learning (SEL). After-school programs are uniquely positioned to build protective and promotive factors that contribute to positive future orientation, especially within communities where systemic inequities create barriers to high school graduation, higher education, employment, and earnings. This study examines Fit2Lead Youth Enrichment and Sports (YES), a county-funded, parks-based after-school collaboration for middle schoolers that merges mental health and recreation to promote healthy trajectories. Eight Miami neighborhood parks were selected based on county data indicating high rates of violence. An open trial design (N = 9 parks, 198 youth; ages 9-15; 40.5% female; 66.5% Black/African American, 24.9% Hispanic/Latinx, and 76.3% low-income) tested hypotheses that participation for adolescents exposed to community violence would disrupt a commonly reported decline in self-regulation and self-efficacy, and mitigate risk for anxiety and depression. Youth completed questionnaires at the beginning and end of one school year. Paired t-tests revealed no changes from pre to post, and no differences by baseline levels of youth and parent mental health. Findings highlight the promise of prevention programs to disrupt downward trajectories for youth during the risky time of early adolescence.

Scalable Synthesis of InAs Quantum Dots Mediated through Indium Redox Chemistry.

Next-generation optoelectronic applications centered in the near-infrared (NIR) and short-wave infrared (SWIR) wavelength regimes require high-quality materials. Among these materials, colloidal InAs quantum dots (QDs) stand out as an infrared-active candidate material for biological imaging, lighting, and sensing applications. Despite significant development of their optical properties, the synthesis of InAs QDs still routinely relies on hazardous, commercially unavailable precursors. Herein, we describe a straightforward single hot injection procedure revolving around In(I)Cl as the key precursor. Acting as a simultaneous reducing agent and In source, In(I)Cl smoothly reacts with a tris(amino)arsenic precursor to yield colloidal InAs quantitatively and at gram scale. Tuning the reaction temperature produces InAs cores with a first excitonic absorption feature in the range of 700-1400 nm. A dynamic disproportionation equilibrium between In(I), In metal, and In(III) opens up additional flexibility in precursor selection. CdSe shell growth on the produced cores enhances their optical properties, furnishing particles with center emission wavelengths between 1000 and 1500 nm and narrow photoluminescence full-width at half-maximum (FWHM) of about 120 meV throughout. The simplicity, scalability, and tunability of the disclosed precursor platform are anticipated to inspire further research on In-based colloidal QDs.

How Effective Is Palliative Care in Improving Patient Outcomes?

OPINION STATEMENT: As palliative care (PC) continues its rapid growth, an emerging body of evidence is demonstrating that its approach of interdisciplinary supportive care benefits many patient populations, including in the oncology setting. As studies and data proliferate, however, questions persist about who, what, why, when, and how PC as well as the ideal time for a PC consult and length of involvement. When comparing outcomes from chemotherapy trials, it is important to consider the dosing regimens used in the various studies. In the same way, it is important to account for the "dose" of the PC interventions utilized across studies, and apples to apples comparisons are needed in order to draw accurate conclusions about PC's benefits. Studies which include a true interdisciplinary PC intervention consistently show improvements in patient quality of life, as well as cost savings, with further study needed for other outcomes. These benefits cannot be extrapolated to care which may be labeled "palliative care," but which does not meet the standard of true interdisciplinary PC. The ultimate question is: Does PC indeed improve outcomes?

Exceedingly small iron oxide nanoparticles as positive MRI contrast agents.

Medical imaging is routine in the diagnosis and staging of a wide range of medical conditions. In particular, magnetic resonance imaging (MRI) is critical for visualizing soft tissue and organs, with over 60 million MRI procedures performed each year worldwide. About one-third of these procedures are contrast-enhanced MRI, and gadolinium-based contrast agents (GBCAs) are the mainstream MRI contrast agents used in the clinic. GBCAs have shown efficacy and are safe to use with most patients; however, some GBCAs have a small risk of adverse effects, including nephrogenic systemic fibrosis (NSF), the untreatable condition recently linked to gadolinium (Gd) exposure during MRI with contrast. In addition, Gd deposition in the human brain has been reported following contrast, and this is now under investigation by the US Food and Drug Administration (FDA). To address a perceived need for a Gd-free contrast agent with pharmacokinetic and imaging properties comparable to GBCAs, we have designed and developed zwitterion-coated exceedingly small superparamagnetic iron oxide nanoparticles (ZES-SPIONs) consisting of ∼3-nm inorganic cores and ∼1-nm ultrathin hydrophilic shell. These ZES-SPIONs are free of Gd and show a high T1 contrast power. We demonstrate the potential of ZES-SPIONs in preclinical MRI and magnetic resonance angiography.

Blue Light Emitting Defective Nanocrystals Composed of Earth-Abundant Elements.

Copper-based ternary (I-III-VI) chalcogenide nanocrystals (NCs) are compositionally-flexible semiconductors that do not contain lead (Pb) or cadmium (Cd). Cu-In-S NCs are the dominantly studied member of this important materials class and have been reported to contain optically-active defect states. However, there are minimal reports of In-free compositions that exhibit efficient photoluminescence (PL). Here, we report a novel solution-phase synthesis of ≈4 nm defective nanocrystals (DNCs) composed of copper, aluminum, zinc, and sulfur with ≈20 % quantum yield and an attractive PL maximum of 450 nm. Extensive spectroscopic characterization suggests the presence of highly localized electronic states resulting in reasonably fast PL decays (≈1 ns), large vibrational energy spacing, small Stokes shift, and temperature-independent PL linewidth and PL lifetime (between room temperature and ≈5 K). Furthermore, density functional theory (DFT) calculations suggest PL transitions arise from defects within a CuAl5 S8 crystal lattice, which supports the experimental observation of highly-localized states. The results reported here provide a new material with unique optoelectronic characteristics that is an important analog to well-explored Cu-In-S NCs.

Zinc Thiolate Enables Bright Cu-Deficient Cu-In-S/ZnS Quantum Dots.

Copper indium sulfide (CIS) colloidal quantum dots (QDs) are a promising candidate for commercially viable QD-based optical applications, for example as colloidal photocatalysts or in luminescent solar concentrators (LSCs). CIS QDs with good photoluminescence quantum yields (PLQYs) and tunable emission wavelength via size and composition control are previously reported. However, developing an understanding and control over the growth of electronically passivating inorganic shells would enable further improvements of the photophysical properties of CIS QDs. To improve the optical properties of CIS QDs, the focus is on the growth of inorganic shells via the popular metal-carboxylate/alkane thiol decomposition reaction. 1) The role of Zn-carboxylate and Zn-thiolate on the formation of ZnS shells on Cu-deficient CIS (CDCIS) QDs is studied, 2) this knowledge is leveraged to yield >90% PLQY CDCIS/ZnS core/shell QDs, and 3) a mechanism for ZnS shells grown from zinc-carboxylate/alkane thiol decomposition is proposed.

Two-Year Changes in Neighborhood Juvenile Arrests After Implementation of a Park-Based Afterschool Mental Health Promotion Program in Miami-Dade County, Florida, 2015-2017.

Objectives. To examine the association of Fit2Lead, an afterschool park-based youth mental health promotion program, and neighborhood juvenile arrests (2015-2017) in Miami-Dade County, Florida. Methods. We tracked juvenile (ages 12-17 years) arrest rates over 2 years of program implementation across zip codes matched by (1) park and (2) baseline sociodemographics and youth arrests. Fit2Lead mental and physical health, meditation, resilience, and life skills activities were offered in 12 high-need areas for youths (n = 501) aged 12 to 17 years. We tested the association of Fit2Lead implementation (binary variable) and change in juvenile arrest rates by zip code, adjusting for area-level gender, age, race/ethnicity, single-parent households, and poverty. Results. Fit2Lead was offered in areas composed of 48% male youths, 60% Hispanics, 29% non-Hispanic Blacks, 33% single-parent households, and 33% of residents living in poverty. After covariate adjustment, zip codes with Fit2Lead implementation showed a significant mean reduction (P < .001) in youth arrests per 10 000 youths aged 12 to 17 years per year compared with zip codes without program implementation (b = -6.9; 95% confidence interval = -9.21, -4.65). Conclusions. Park-based programs may have the potential to promote mental health and resilience, and also to prevent violence among at-risk youths.