Changes in Facility Share of Medicaid-insured Patients With Urologic Cancers Following Implementation of the Patient Protection and Affordable Care Act.

OBJECTIVE: To examine Medicaid-insurance acceptance at facilities treating urologic cancers following implementation of the Affordable Care Act (ACA). METHODS: We conducted a retrospective, longitudinal study with a pre-post design. We accessed 2010-2017 data from the National Cancer Database, calculating the facility-level change in proportion of urologic cancer patients with Medicaid following implementation of the ACA. We used multivariable logistic regression to assess baseline clinical and demographic factors associated with changes in the proportion of patients at a facility insured through Medicaid. RESULTS: We identified 630 facilities, including 287 in Medicaid expansion states and 343 in non-expansion states associated with 436,082 urologic cancer patients. The mean facility-level change in proportion of patients with Medicaid was + 5.8% (95% CI 5.0%-6.5%) in expansion states versus + 0.6% (95% CI 0.2%-0.9%) in non-expansion states. There were 179 facilities that experienced a decrease in the post-ACA period, representing 13.6% of facilities in expansion states and 40.8% in non-expansion states (P <.001). Factors associated with a decrease in proportion of urologic cancer patients insured by Medicaid included non-expansion state status (OR 8.9, 95% CI 5.3-15.6, P <.001), higher baseline proportion of patients with Medicaid (highest quartile vs lowest: OR 4.6, 95% CI 2.3-9.4, P <.001) and high-income zip code (highest vs lowest quartile: OR 3.1, 95% CI 1.5-6.6, P <.001). CONCLUSION: Urologic cancer care for Medicaid-insured Americans remains unevenly distributed across cancer care centers, even in states that expanded coverage. Our findings suggest that this variation may reflect the effort of some facilities to reduce their financial exposure to increased numbers of Medicaid patients in the wake of ACA-supported state expansions.

Implementation of a health system intervention to reduce time from presentation to surgical intervention for pediatric testicular torsion.

PURPOSE: Testicular salvage rates for torsion are time-dependent1. Door to detorsion time has been identified as an independent testicular survival factor2. We describe an initiative to reduce door to incision (DTI) time for pediatric testicular torsion. MATERIALS AND METHODS: An institutional multidisciplinary quality improvement initiative with a primary outcome of reducing DTI time for pediatric testicular torsion was developed with multidisciplinary stakeholders. Several process and balancing measures were used as secondary outcomes to help interpret and verify the observed change in DTI time. Interventions were implemented in cycles. Initial interventions standardized assessment of suspected torsion by Emergency Medicine utilizing a validated scoring system. A threshold Testicular Workup for Ischemia and Suspected Torsion (TWIST) score led to parallel notification of essential services for rapid assessment and case prioritization3. Subsequently, bedside ultrasound in the Emergency Department was implemented. Progress was tracked in a live dashboard and analyzed with X-mR process control charts and Nelson rules. These tools are used in quality improvement and process control to demonstrate the significance of changes as they are being implemented, prior to when traditional hypothesis testing would be able to do so. We aimed to increase the proportion of cases with DTI times under 4 h from 64% to >90% within one year. RESULTS: We observed 22 torsion cases prior to and 62 following initial implementation. The percentage of cases with DTI times under 4 h improved from 64% to 95%. At week 29, a shift identified a significant change on the X chart, with reduction in mean DTI time from 221 to 147 min. At the same time, a shift on the mR chart identified reduction in patient-to-patient variation. Mean time from arrival to Urology evaluation decreased from 140 to 56 min, mean time from arrival to scrotal ultrasound decreased from 70 to 36 min, and mean time from scrotal ultrasound to surgical incision decreased from 128 to 80 min. These improvements highlight the two key successes of our project: application of the TWIST score and bedside ultrasound for rapid assessment of suspected testicular torsions, and parallel processing of the evaluation and management. CONCLUSIONS: Implementation of a protocol for pediatric testicular torsion increased the proportion of cases with DTI time <4 h to 95%, decreased mean DTI time, and decreased variation. Our protocol provides a model to improve timeliness of care in treating pediatric testicular torsion.

A TriNetX Registry Analysis of the Need for Second Procedures following Index Anterior and Posterior Urethroplasty.

BACKGROUND: We queried a global database to understand re-intervention rates following urethroplasty with the goal of evaluating whether they align with previously published data. METHODS: Using the TriNetX database and Common Procedural Terminology (CPT) and International Classification of Diseases-10 (ICD) codes, we identified adult male patients with urethral stricture disease (ICD N35) who underwent one-stage anterior (CPT 53410) or posterior urethroplasty (CPT 53415), with or without (substitution urethroplasty) a tissue flap (CPT 15740) or buccal graft (CPT 15240 or 15241). We set urethroplasty as the index event and used descriptive statistics to report the incidence of secondary procedures (using CPT codes) within 10 years after the index event. RESULTS: There were 6606 patients who underwent urethroplasty within the last 20 years, with 14.3% of patients undergoing a second procedure after index event. Upon subgroup analysis, reintervention rates were 14.5% for anterior urethroplasty vs. 12.4% of patients with an anterior substitution urethroplasty (RR 1.7, p = 0.09) and 13.3% for posterior urethroplasty vs. 8.2% for patients with a posterior substitution urethroplasty (RR 1.6, p < 0.01). CONCLUSIONS: Most patients will not need any form of re-intervention following urethroplasty. These data align with previously described recurrence rates, which may help urologists counsel patients considering urethroplasty.

Access to urologic cancer care for Medicaid-insured patients.

BACKGROUND: The expansion of state Medicaid programs associated with the Affordable Care Act has led to significant increases in insurance coverage for economically vulnerable patients, however barriers to accessing cancer care still exist. To develop strategies to improve healthcare access, we characterized access to new urologic cancer care for patients with Medicaid insurance in the United States. METHODS: Using a secret shopper approach, we contacted a representative sample of facilities designated for cancer care in United States. Trained volunteers posed as a family member seeking urologic cancer care using a simulated scenario of a parent with a new diagnosis of a localized kidney tumor. The primary study outcome was acceptance of Medicaid. In addition, we assessed facility characteristics associated with Medicaid acceptance relating to state Medicaid expansion status, Medicare reimbursement rates, and teaching hospital status using data from the Medicare & Medicaid Services Hospital General Information data file, the American Hospital Directory, and the American Medical Association of Colleges Organizational Characteristics Database. RESULTS: We sampled a total of 389 facilities, of which 14.4% did not accept new Medicaid patients. Medicaid acceptance was higher in facilities located in states that elected to expand Medicaid through the ACA vs. non-expansion states (90.1% vs. 77.4% respectively, P < 0.001). Facilities accepting patients with Medicaid were located in states with higher mean Medicaid-to-Medicare fee indexes (0.70 for Medicaid-accepting vs. 0.65 for non-accepting facilities, P < 0.001). In addition, Medicaid acceptance was higher in teaching hospitals vs. non-teaching facilities (93.8% vs. 83.4% P = 0.02), and medical school affiliated facilities (89.2% vs. 79.7% P = 0.01). CONCLUSION: We identified access disparities for patients with Medicaid insurance seeking urologic cancer care at centers. These findings highlight opportunities to improve the quality and timeliness of cancer care.

Using Peritumor and Intratumor Vascularity on Preoperative Imaging to Predict Fuhrman Grade Histology of Renal Tumors.

Objective: To investigate if peritumor and/or intratumor vasculature is associated with high-grade tumor histology for renal cell carcinoma. Methods: A retrospective review at a tertiary care facility was performed of patients who underwent radical nephrectomy or partial nephrectomy for a renal tumor between January 2015 and December 2020. Data of tumor characteristics were collected from final pathology reports. A single radiologist specializing in genitourinary imaging reviewed all preoperative cross-sectional imaging for peritumor vessels and intratumor vessels. Single and multivariable logistic regression was utilized to identify variables associated with high-grade tumor histology. Results: The average tumor size on final pathology report was 6.4 cm (range 3.0-17.0 cm). Ninety-two patients (56.1%) had either an enlarged peritumor vessel (n = 72), an intratumor vessel (n = 3), or both a peritumor vessel and an intratumor vessel (n = 17). Of the 92 patients with either a peritumor vessel or both a peritumor vessel and intratumor vessel, 60.9% of these patients had high Fuhrman grade histology on final pathology report (60.9% vs 39.1%, p < 0.001). Pathologic stage T1a tumors with an enlarged peritumor vessel on preoperative imaging were associated with high Fuhrman grade histology (58.3% vs 41.7%, p = 0.015). Across all stages, the presence of an enlarged peritumor vessel was significantly associated with high Fuhrman grade (odds ratio: 2.37, 95% confidence interval 1.17-4.9, p = 0.01). Conclusion: Findings suggest that vessels surrounding small renal tumors and large renal tumors is associated with high tumor grade (Fuhrman grade >3). Further research is needed to support the association of peritumor vessels with high tumor grade.

Facility-Level Variation in Use of Locoregional Therapy for Metastatic Prostate Cancer.

INTRODUCTION: We sought to understand patient- and institution-level factors associated with use of locoregional therapy for newly diagnosed metastatic prostate cancer in the era before the availability of evidence supporting its efficacy. METHODS: We queried the National Cancer Database to identify patients diagnosed with metastatic prostate adenocarcinoma (stage M1) between 2004 and 2017. We assessed patient factors associated with definitive local therapy with radiotherapy or radical prostatectomy using multilevel logistic regression accounting for clustering within institutions. We further characterized trends in facility-level use and examined institutional factors associated with utilization. RESULTS: We identified 35,933 patients with M1 prostate cancer at 1,188 facilities. A total of 4,146 patients (11.5%) received local therapy for M1 disease (radiation therapy in 3,378 and radical prostatectomy in 768). Use of local treatment was concentrated among a smaller number of facilities: 50% of all local therapy was delivered at 161 facilities (14% of total). At the patient level, uninsured status (OR 0.62, 95% CI 0.49-0.79, p <0.01) and high comorbidity (Charlson-Deyo score, OR 0.39, 95% CI 0.26-0.6, p <0.01) were associated with lower odds of local therapy. High-utilizing facilities (top quartile) were more commonly community centers (OR 1.76, 95% CI 10.7-2.95, p <0.01) and differed by geographic region (South Atlantic vs West South Central region: OR 0.48, 95% CI 0.25-0.88, p=0.02). CONCLUSIONS: In the period before locoregional therapy was supported by clinical practice guidelines, locoregional therapy use varied significantly at the facility level and was driven by a smaller number of high-utilizing facilities. These findings can contextualize expected increase in the use of local therapy for metastatic prostate cancer.

Management of a rhegmatogenous retinal detachment in a pregnant patient.

PURPOSE: To describe the management of a rhegmatogenous retinal detachment (RRD) in a pregnant patient. OBSERVATIONS: A 30-year-old, 26-week pregnant female presented with curtain vision loss in the left eye. Exam findings were significant in the left eye for an inferior fovea-sparing RRD. Care was coordinated and discussed with anesthesia and OB/GYN. The patient underwent surgery with monitored anesthesia care and a 41 scleral buckle, cryotherapy and C3F8 gas. The retina remained attached at 4 months post-operatively. A healthy girl was delivered via spontaneous vaginal delivery at 39 weeks. CONCLUSION: Safe and successful treatment of RRD in pregnant patients can be achieved with careful coordination between ophthalmology, anesthesia, and obstetrics. An understanding of pregnancy specific considerations is important in order to optimize patient outcomes.

The Role of Liquid Ink Transport in the Direct Placement of Quantum Dot Emitters onto Sub-Micrometer Antennas by Dip-Pen Nanolithography.

Dip-pen nanolithography (DPN) is used to precisely position core/thick-shell ("giant") quantum dots (gQDs; ≥10 nm in diameter) exclusively on top of silicon nanodisk antennas (≈500 nm diameter pillars with a height of ≈200 nm), resulting in periodic arrays of hybrid nanostructures and demonstrating a facile integration strategy toward next-generation quantum light sources. A three-step reading-inking-writing approach is employed, where atomic force microscopy (AFM) images of the pre-patterned substrate topography are used as maps to direct accurate placement of nanocrystals. The DPN "ink" comprises gQDs suspended in a non-aqueous carrier solvent, o-dichlorobenzene. Systematic analyses of factors influencing deposition rate for this non-conventional DPN ink are described for flat substrates and used to establish the conditions required to achieve small (sub-500 nm) feature sizes, namely: dwell time, ink-substrate contact angle and ink volume. Finally, it is shown that the rate of solvent transport controls the feature size in which gQDs are found on the substrate, but also that the number and consistency of nanocrystals deposited depends on the stability of the gQD suspension. Overall, the results lay the groundwork for expanded use of nanocrystal liquid inks and DPN for fabrication of multi-component nanostructures that are challenging to create using traditional lithographic techniques.

Randomized Clinical Trial of Computerized and Clinician-Delivered CBT in Comparison With Standard Outpatient Treatment for Substance Use Disorders: Primary Within-Treatment and Follow-Up Outcomes.

OBJECTIVE: Previous trials have demonstrated the efficacy and durability of computer-based cognitive-behavioral therapy (CBT4CBT) as an add-on to standard outpatient care in a range of treatment-seeking populations. In this study, the authors evaluated the efficacy and safety of CBT4CBT as a virtual stand-alone treatment, delivered with minimal clinical monitoring, and clinician-delivered cognitive-behavioral therapy (CBT) compared with treatment as usual in a heterogeneous sample of treatment-seeking outpatients with substance use disorders. METHOD: This was a randomized clinical trial in which 137 individuals who met DSM-IV-TR criteria for current substance abuse or dependence were randomly assigned to receive treatment as usual, weekly individual CBT, or CBT4CBT with brief weekly monitoring. RESULTS: Rates of treatment exposure differed by group, with the best retention in the CBT4CBT group and the poorest in the individual CBT group. Participants who received CBT or CBT4CBT reduced their frequency of substance use significantly more than those who received treatment as usual. Six-month follow-up outcomes indicated continuing benefit of CBT4CBT (plus monitoring) over treatment as usual, but not for clinician-delivered CBT over treatment as usual. Analysis of secondary outcomes indicated that participants in the CBT4CBT group demonstrated the best learning of cognitive and behavioral concepts, as well as the highest satisfaction with treatment. CONCLUSIONS: This first trial of computerized CBT as a virtual stand-alone intervention delivered in a clinical setting to a diverse sample of patients with current substance use disorders indicated that it was safe, effective, and durable relative to standard treatment approaches and was well-liked by participants. Clinician-delivered individual CBT, while efficacious within the treatment period, was unexpectedly associated with a higher dropout rate and lower effects at follow-up.

Biexciton and trion energy transfer from CdSe/CdS giant nanocrystals to Si substrates.

Observation of energy transfer (ET) from multiexcitonic (MX) complexes in nanocrystal quantum dots (NQDs) has been severely restricted due to efficient nonradiative Auger recombination leading to very low MX emission quantum yields. Here we employed "giant" CdSe/CdS NQDs with suppressed Auger recombination to study ET of biexcitons (BX) and charged excitons (trions) into Si substrate. Photoluminescence (PL) measurements of (sub)monolayers of gNQDs controllably assembled on various interacting surfaces and augmented by single gNQD's imaging reveal appearance of BX spectral signatures and progressive acceleration of PL lifetimes of all excitonic species on Si substrates. From statistical analysis of a large number of PL lifetime traces, representative exciton, trion and BX ET efficiencies are measured as ∼75%, 55% and 45% respectively. Detailed analysis of the MX's radiative rates demonstrate the crucial role of the radiative (waveguide) ET in maintaining high overall transfer efficiency despite the prevalent Auger recombination. Our observations point towards practical utilization of MX-bearing nanocrystals in future optoelectronics architectures.

Effect of computerized cognitive behavioral therapy on acquisition of coping skills among cocaine-dependent individuals enrolled in methadone maintenance.

The acquisition of coping skills has long been considered one of the putative mechanisms of cognitive behavioral therapy (CBT) for substance use disorders, yet consistent statistical support is lacking. This study sought to replicate and extend prior findings regarding the quality of coping skills as a mediator of abstinence outcomes from a computerized CBT program for substance users. Participants were methadone-maintained, cocaine dependent individuals enrolled in a clinical trial evaluating the efficacy of computer-based training for CBT ('CBT4CBT') as an add-on to treatment as usual (TAU+CBT4CBT) compared to TAU only. A subsample (N=71) completed a role play assessment to measure coping skills, the Drug Risk Response Test (DRRT), which was administered before, during (week 4), and after the 8-week treatment period. Participants' verbal responses to various high-risk situations for cocaine use were recorded and independent evaluators rated the quality of the coping responses. Results of repeated measures analyses revealed a main effect of time for the quality of overall responses [F(1, 141.26)=4.29, p<0.01], indicating improvement in the quality of coping skills across groups, yet no differential effect of treatment. Despite the significant association between coping responses and abstinence outcomes, analyses did not support the quality of coping skills as a mediator of treatment effects. However, among the high-risk situations wherein individuals provided lower quality responses at baseline, those assigned to TAU+CBT4CBT showed greater improvement compared to those assigned to TAU only [F(1, 697.65)=6.47, p=0.01]. CONCLUSIONS: This study failed to replicate the quality of coping skills as a mediator of CBT4CBT's effect on reducing drug use previously shown in a mixed outpatient substance use sample. However, in this methadone maintained sample, those with poorer quality skills in response to certain high-risk situations at baseline appeared to improve their coping strategies following CBT4CBT compared to standard methadone treatment alone.

Traceless Cleavage of Protein-Biotin Conjugates under Biologically Compatible Conditions.

Biotinylation of amines is widely used to conjugate biomolecules, but either the resulting label is non-removable or its removal leaves a tag on the molecule of interest, thus affecting downstream processes. We present here a set of reagents (RevAmines) that allow traceless, reversible biotinylation under biologically compatible, mild conditions. Release following avidin-based capture is achieved through the cleavage of a (2-(alkylsulfonyl)ethyl) carbamate linker under mild conditions (200 mm ammonium bicarbonate, pH 8, 16-24 h, room temperature) that regenerates the unmodified amine. The capture and release of biotinylated proteins and peptides from neutravidin, fluorescent labelling through reversible biotinylation at the cell surface and the selective enrichment of proteins from bacterial periplasm are demonstrated. The tags are easily prepared, stable and offer the potential for future application in proteomics, activity-based protein profiling, affinity chromatography and bio-molecule tagging and purification.

Strong plasmonic enhancement of biexciton emission: controlled coupling of a single quantum dot to a gold nanocone antenna.

Multiexcitonic transitions and emission of several photons per excitation comprise a very attractive feature of semiconductor quantum dots for optoelectronics applications. However, these higher-order radiative processes are usually quenched in colloidal quantum dots by Auger and other nonradiative decay channels. To increase the multiexcitonic quantum efficiency, several groups have explored plasmonic enhancement, so far with moderate results. By controlled positioning of individual quantum dots in the near field of gold nanocone antennas, we enhance the radiative decay rates of monoexcitons and biexcitons by 109 and 100 folds at quantum efficiencies of 60 and 70%, respectively, in very good agreement with the outcome of numerical calculations. We discuss the implications of our work for future fundamental and applied research in nano-optics.

Performance-Based Contingency Management in Cognitive Remediation Training: A Pilot Study.

Impairments in attention, working memory, and executive function are common among substance users and may adversely affect SUD treatment outcomes. The ability of cognitive remediation (CR) interventions to improve these deficits is hindered in part because levels of engagement in CR training may be inadequate to achieve benefit. This pilot study aimed to increase CR engagement and improve outcome by implementing contingency management (CM) procedures that reinforce performance improvements on CR tasks. Participants were forty individuals (50% male; 65% African American) in an outpatient substance use treatment facility with mild cognitive impairment who had ≥30-days of abstinence from alcohol and drugs. They were randomized to standard (CR-S; n=21) or CM-enhanced (CR-CM; n=19) cognitive remediation training. CR consisted of 1-hour sessions, three times per week for four weeks (12 sessions). A neuropsychological assessment battery was administered prior to and after the four-week intervention. Both groups had high rates of CR session attendance (mean CR-S=11.7, CR-CM=10.9 sessions). Performance on 8 of the 9 CR tasks significantly improved over time for both conditions, with the CR-CM condition demonstrating greater improvement on a CR Sequenced Recall task [F(1,37)=5.81, p<.05]. Significant improvement was also evident on 4 of 9 neuropsychological assessment measures, with the CR-CM condition showing differential improvement on the Trail Making Test - Part B [F (1,37)=5.34, p<.05]. These findings support the feasibility of using CM procedures to enhance substance users' engagement with CR training and suggest the potential value of more research in this area.

Randomized Trial of Computerized Cognitive Behavioral Therapy for Alcohol Use Disorders: Efficacy as a Virtual Stand-Alone and Treatment Add-On Compared with Standard Outpatient Treatment.

BACKGROUND: Cognitive behavioral therapy (CBT) is an evidence-based treatment for alcohol use disorders (AUDs), yet is rarely implemented with high fidelity in clinical practice. Computer-based delivery of CBT offers the potential to address dissemination challenges, but to date there have been no evaluations of a web-based CBT program for alcohol use within a clinical sample. METHODS: This study randomized treatment-seeking individuals with a current AUD to 1 of 3 treatments at a community outpatient facility: (i) standard treatment as usual (TAU); (ii) TAU plus on-site access to a computerized CBT targeting alcohol use (TAU + CBT4CBT); or (iii) CBT4CBT plus brief weekly clinical monitoring (CBT4CBT + monitoring). Participant alcohol use was assessed weekly during an 8-week treatment period, as well as 1, 3, and 6 months after treatment. RESULTS: Sixty-eight individuals (65% male; 54% African American) were randomized (TAU = 22; TAU + CBT4CBT = 22; CBT4CBT + monitoring = 24). There were significantly higher rates of treatment completion among participants assigned to 1 of the CBT4CBT conditions compared to TAU (Wald = 6.86, p < 0.01). Significant reductions in alcohol use were found across all conditions within treatment, with participants assigned to TAU + CBT4CBT demonstrating greater increases in percentage of days abstinent (PDA) compared to TAU, t(536.4) = 2.68, p < 0.01, d = 0.71, 95% CI (0.60, 3.91), for the full sample. Preliminary findings suggest the estimated costs of all self-reported AUD-related services utilized by participants were considerably lower for those assigned to CBT4CBT conditions compared to TAU, both within treatment and during follow-up. CONCLUSIONS: This trial demonstrated the safety, feasibility, and preliminary efficacy of web-based CBT4CBT targeting alcohol use. CBT4CBT was superior to TAU at increasing PDA when delivered as an add-on, and it was not significantly different from TAU or TAU + CBT4CBT when delivered with clinical monitoring only.

Mechanistic examination of aerobic Pt oxidation: insertion of molecular oxygen into Pt-H bonds through a radical chain mechanism.

DFT calculations were performed in an effort to evaluate the mechanism of O2 insertion into the Pt-H bond of Tp(Me2)Pt(IV)Me2H catalyzed by AIBN or light. Results are consistent with a radical chain mechanism involving H˙ loss to form a Pt(III)˙ species followed by addition of O2 to form Pt(III)OO˙. Subsequent radical propagation involving this Pt(III)OO˙ species and an additional equivalent of the Pt(IV) starting material result in the formation of the observed Pt(IV)OOH and regeneration of the Pt(III)˙. In addition examination of the reaction between AIBN and the Pt(IV) hydroperoxo product demonstrates that radical initiation reactions involving the product occur with a lower barrier than with the initial starting material supporting the idea of autoacceleration in this reaction. Other possible mechanisms were examined in an effort to understand the limited reactivity reported in the absence of light or radical initiators. TDDFT calculations were performed in an effort to understand the reported parallel photo-induced reaction. These calculations found the reactant to be transparent in the relevant light range. An experimental UV-Vis spectrum was obtained and is in agreement with the calculations.

Quantum Yield Heterogeneity among Single Nonblinking Quantum Dots Revealed by Atomic Structure-Quantum Optics Correlation.

Physical variations in colloidal nanostructures give rise to heterogeneity in expressed optical behavior. This correlation between nanoscale structure and function demands interrogation of both atomic structure and photophysics at the level of single nanostructures to be fully understood. Herein, by conducting detailed analyses of fine atomic structure, chemical composition, and time-resolved single-photon photoluminescence data for the same individual nanocrystals, we reveal inhomogeneity in the quantum yields of single nonblinking "giant" CdSe/CdS core/shell quantum dots (g-QDs). We find that each g-QD possesses distinctive single exciton and biexciton quantum yields that result mainly from variations in the degree of charging, rather than from volume or structure inhomogeneity. We further establish that there is a very limited nonemissive "dark" fraction (<2%) among the studied g-QDs and present direct evidence that the g-QD core must lack inorganic passivation for the g-QD to be "dark". Therefore, in contrast to conventional QDs, ensemble photoluminescence quantum yield is principally defined by charging processes rather than the existence of dark g-QDs.

Matching Solid-State to Solution-Phase Photoluminescence for Near-Unity Down-Conversion Efficiency Using Giant Quantum Dots.

Efficient, stable, and narrowband red-emitting fluorophores are needed as down-conversion materials for next-generation solid-state lighting that is both efficient and of high color quality. Semiconductor quantum dots (QDs) are nearly ideal color-shifting phosphors, but solution-phase efficiencies have not traditionally extended to the solid-state, with losses from both intrinsic and environmental effects. Here, we assess the impacts of temperature and flux on QD phosphor performance. By controlling QD core/shell structure, we realize near-unity down-conversion efficiency and enhanced operational stability. Furthermore, we show that a simple modification of the phosphor-coated light-emitting diode device-incorporation of a thin spacer layer-can afford reduced thermal or photon-flux quenching at high driving currents (>200 mA).

Emerging strategies for the total synthesis of inorganic nanostructures.

New synthetic innovations are rapidly being developed to address the demand for complex, next-generation nanomaterials with rigorously controlled architectures and interfaces. This Review highlights key strategies for the chemical transformation and stepwise synthesis of multicomponent inorganic nanostructures, with the existing nanoscale transformations categorized into classes of reactions that are related to those used in the synthesis of organic molecules. The application of concepts used in molecular synthesis--including site-selectivity, regio- and chemoselectivity, orthogonal reactivity, coupling reactions, protection/deprotection strategies, and procedures for separation and purification--to nanoscale systems is emphasized. Collectively, the resulting synthetic concept represents an emerging model for the synthesis of complex inorganic nanostructures on the basis of the guiding principles that underpin the multistep total synthesis of complex organic molecules and natural products.

A total-synthesis framework for the construction of high-order colloidal hybrid nanoparticles.

Colloidal hybrid nanoparticles contain multiple nanoscale domains fused together by solid-state interfaces. They represent an emerging class of multifunctional lab-on-a-particle architectures that underpin future advances in solar energy conversion, fuel-cell catalysis, medical imaging and therapy, and electronics. The complexity of these 'artificial molecules' is limited ultimately by the lack of a mechanism-driven design framework. Here, we show that known chemical reactions can be applied in a predictable and stepwise manner to build complex hybrid nanoparticle architectures that include M-Pt-Fe(3)O(4) (M = Au, Ag, Ni, Pd) heterotrimers, M(x)S-Au-Pt-Fe(3)O(4) (M = Pb, Cu) heterotetramers and higher-order oligomers based on the heterotrimeric Au-Pt-Fe(3)O(4) building block. This synthetic framework conceptually mimics the total-synthesis approach used by chemists to construct complex organic molecules. The reaction toolkit applies solid-state nanoparticle analogues of chemoselective reactions, regiospecificity, coupling reactions and molecular substituent effects to the construction of exceptionally complex hybrid nanoparticle oligomers.