A Sensitive Assay for Unbound Docetaxel Using Ultrafiltration plus HPLC-MS and Its Application to a Clinical Study.

INTRODUCTION: Docetaxel, a taxane used in the treatment of solid tumours, exerts pharmacological activity when in its unbound form. We report a sensitive assay to quantify unbound docetaxel after oral administration of docetaxel plus encequidar (oDox+E). Unbound drug quantification is important due to its direct correlation with drug-related toxicity and therapeutic efficacy. We improve on the sensitivity of current assay methods and demonstrate the utility of the assay on a novel formulation of oral docetaxel. METHODS: Ultrafiltration followed by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) was utilized. Long-term stability, precision, accuracy, and recovery experiments were conducted to validate the assay. Additionally, patient samples from a Phase I dose-escalation pharmacokinetic study were analyzed using the developed assay. RESULTS: The assay method exhibited long-term stability with an observed change between 0.8 and 6.9% after 131 days of storage at -60 °C. Precision and accuracy quality controls met the FDA acceptance criteria. An average recovery of 88% was obtained. Patient sample analysis demonstrated successful implementation of the assay. CONCLUSION: A validated sensitive assay was developed with an LLOQ of 0.084 ng/mL using 485 µL of human plasma. The sensitivity of the assay allowed quantification of unbound docetaxel concentrations in an early-phase oDox+E clinical study to compare it against IV docetaxel using pharmacokinetic modelling. Successful development of oDox+E represents an opportunity to replace the current IV docetaxel regimen with an oral regimen with lower cost, decreased side effects, and improve patient quality of life and experience.

Oral docetaxel plus encequidar - a phase 1 clinical trial.

PURPOSE: To determine the bioavailability, safety, and tolerability of a single dose of oral docetaxel plus encequidar (oDox + E) and compare its pharmacokinetic exposure with current standard of care IV docetaxel. INTRODUCTION: Docetaxel is a taxane widely used as an anti-neoplastic agent. Due to low oral bioavailability secondary to gut P-glycoprotein (P-gp) efflux, its current use is limited to intravenous administration. Oral docetaxel may provide a less resource intensive, more convenient, and tolerable alternative. Encequidar is a first in class, minimally absorbed, oral gut-specific P-gp inhibitor. We tested whether oDox + E can achieve comparable pharmacokinetic exposure to IV docetaxel. METHODS: A multicentre, phase I open-label, pharmacokinetic trial was undertaken to determine the bioavailability, safety, and tolerability of a single dose of oDox + E (at 75 mg/m2 + 15 mg, 150 mg/m2 + 15 mg, and 300 mg/m2 + 15 mg) in metastatic prostate cancer (mPC) patients compared to standard of care IV docetaxel as prescribed by their oncologists. The 15 mg of Encequidar at each dose level was given one hour prior to oral docetaxel. RESULTS: 11 patients were enrolled; 9 patients completed the study. Oral docetaxel exposure increased with dose, achieving the highest at 300 mg/m2 oDox + E (with AUC0 - infinity of 1343.3 ± 443.0 ng.h/mL compared to the IV docetaxel AUC0 - infinity of 2000 ± 325 ng.h/mL) and became non-linear at 300 mg/m2. The mean absolute bioavailability of oDox + E across all 3 dose levels was 16.14% (range: 8.19-25.09%). No patient deaths, dose limiting toxicity, treatment-related serious adverse event or grade 4 toxicity were observed. Maximal tolerated dose was not reached. CONCLUSION: oDox + E has a safe and tolerable adverse event profile in patients with metastatic prostate cancer. The increase in oral bioavailability of oDox + E suggests a multi-dose oDox + E regimen could theoretically achieve exposures comparable with standard of care IV docetaxel. Further development to examine the optimal multiple dose regimen of oDox + E is warranted. TRIAL REGISTRATION NUMBER: U1111-1173-5473.

Oral docetaxel plus encequidar - A pharmacokinetic model and evaluation against IV docetaxel.

The development of optimized dosing regimens plays a crucial role in oncology drug development. This study focused on the population pharmacokinetic modelling and simulation of docetaxel, comparing the pharmacokinetic exposure of oral docetaxel plus encequidar (oDox + E) with the standard of care intravenous (IV) docetaxel regimen. The aim was to evaluate the feasibility of oDox + E as a potential alternative to IV docetaxel. The article demonstrates an approach which aligns with the FDA's Project Optimus which aims to improve oncology drug development through model informed drug development (MIDD). The key question answered by this study was whether a feasible regimen of oDox + E existed. The purpose of this question was to provide an early GO / NO-GO decision point to guide drug development and improve development efficiency. METHODS:  A stepwise approach was employed to develop a population pharmacokinetic model for total and unbound docetaxel plasma concentrations after IV docetaxel and oDox + E administration. Simulations were performed from the final model to assess the probability of target attainment (PTA) for different oDox + E dose regimens (including multiple dose regimens) in relation to IV docetaxel using AUC over effective concentration (AUCOEC) metric across a range of effective concentrations (EC). A Go / No-Go framework was defined-the first part of the framework assessed whether a feasible oDox + E regimen existed (i.e., a PTA ≥ 80%), and the second part defined the conditions to proceed with a Go decision. RESULTS:  The overall population pharmacokinetic model consisted of a 3-compartment model with linear elimination, constant bioavailability, constant binding mechanics, and a combined error model. Simulations revealed that single dose oDox + E regimens did not achieve a PTA greater than 80%. However, two- and three-dose regimens at 600 mg achieved PTAs exceeding 80% for certain EC levels. CONCLUSION:  The study demonstrates the benefits of MIDD using oDox + E as a motivating example. A population pharmacokinetic model was developed for the total and unbound concentration in plasma of docetaxel after administration of IV docetaxel and oDox + E. The model was used to simulate oDox + E dose regimens which were compared to the current standard of care IV docetaxel regimen. A GO / NO-GO framework was applied to determine whether oDox + E should progress to the next phase of drug development and whether any conditions should apply. A two or three-dose regimen of oDox + E at 600 mg was able to achieve non-inferior pharmacokinetic exposure to current standard of care IV docetaxel in simulations. A Conditional GO decision was made based on this result and further quantification of the "effective concentration" would improve the ability to optimise the dose regimen.

Optimal sample selection applied to information rich, dense data.

Dense data can be classified into superdense information-poor data (type 1 dense data) and dense information-rich data (type 2 dense data). Arbitrary, random, or optimal thinning may be applied to type 1 dense data to minimise computational burden and statistical issues (such as autocorrelation). In contrast, a prospective or retrospective optimal design can be applied to type 2 dense data to maximise information gain from limited resources (capital and/or time). Here we describe a retrospective optimal selection strategy for quantification of unbound drug concentration from a discrete set of plasma samples where the total drug concentration has been measured.

In Situ Tracking of Crystal-Surface-Dependent Cu2O Nanoparticle Dissolution in an Aqueous Environment.

Metal-oxide-based nanoparticles (MONPs) such as Cu2O NPs have attracted growing attention, but the potential discharges of MONPs have raised considerable concern of their environmental fate including their dissolution behavior. The impacts of morphology on MONP dissolution are largely uncertain due to the lack of in situ tracking techniques. In this study, we combined a series of in situ technologies including liquid-cell transmission electron microscopy and fluorescence probes to reveal the in situ dissolution process of Cu2O NPs in freshwater. Our results suggest that cubic Cu2O NPs exhibit a higher dissolution quantity compared with spherical NPs of the same surface area. The difference was mainly related to the crystal surface, while other factors such as particle size or aggregation status showed minor effects. Importantly, we demonstrated the simultaneous growth of new small NPs and the dissolution of pristine Cu2O NPs during the dissolution of Cu2O NPs. Cubic Cu2O NPs became much less soluble under O2-limited conditions, suggesting that O2 concentration largely affected the dependence of dissolution on the NP morphology. Our findings highlight the potential application of in situ techniques to track the environmental fates of MONPs, which would provide important information for assessing the ecological risks of engineered NPs.

Population pharmacokinetics for oral paclitaxel in patients with advanced/metastatic solid tumors.

Oraxol consists of an oral dosage form of the chemotherapeutic agent paclitaxel administered with a novel P-glycoprotein inhibitor encequidar methanesulfonate monohydrate (formerly named HM30181A), which allows oral treatment of cancers that would otherwise be treated with intravenous paclitaxel. Here we describe the population pharmacokinetics (popPK) analyses for oral paclitaxel in patients with advanced/metastatic solid tumors to characterize pharmacokinetic (PK) profiles and quantify sources of PK variability. The best fit popPK model for oral paclitaxel, based on data from seven clinical studies (197 patients with advanced/metastatic solid tumors), involves a linear two-compartment structural model containing first-order absorption with a short lag time and first-order elimination as well as a log additive error. In this popPK model, lower population estimates of central volume for Asian patients versus Caucasian patients did not translate into clinical meaningful differences in oral paclitaxel exposure. Age, sex, body weight or surface area, mild hepatic impairment, and mild to moderate renal impairment had no clinically meaningful effects on the systemic exposure of oral paclitaxel. Simulations were performed on clinical therapeutic dose (oral paclitaxel 205 mg/m2 once daily ×3 days per week) to predict exposure of oral paclitaxel and to support treatment benefits observed in a pivotal phase III trial.

Oral paclitaxel with encequidar compared to intravenous paclitaxel in patients with advanced cancer: A randomised crossover pharmacokinetic study.

AIMS: Paclitaxel is a widely used anti-neoplastic agent but has low oral bioavailability due to gut extrusion by P-glycoprotein (P-gp). Oral paclitaxel could be more convenient, less resource intensive, and more tolerable than intravenous administration. Encequidar (HM30181A) is a novel, minimally absorbed gut-specific P-gp inhibitor. We tested whether administration of oral paclitaxel with encequidar (oPac+E) achieved comparable AUC to intravenous paclitaxel (IVP) 80 mg/m2 . METHODS: We conducted a multi-centre randomised crossover study with two treatment periods. Patients (pts) with advanced cancer received either oral paclitaxel 615 mg/m2 divided over 3 days and encequidar 15 mg orally 1 hour prior, followed by IVP 80 mg/m2 , or the reverse sequence. PK blood samples were taken up to Day 9 for oPac+E and Day 5 for IVP. RESULTS: Forty-two patients were enrolled; 35 completed both treatment periods. AUC0-∞ was 5033.5 ± 1401.1 ng.h/mL for oPac+E and 5595.9 ± 1264.1 ng.h/mL with IVP. The geometric mean ratio (GMR) for AUC was 89.50% (90% CI 83.89-95.50). Mean absolute bioavailability of oPac+E was 12% (CV% = 23%). PK parameters did not change meaningfully after 4 weeks administration of oPac+E in an extension study. G3 treatment-emergent adverse events occurred in seven (18%) pts with oPac+E and two (5%) with IVP. Seventy-five per cent of patients preferred oPac+E over IVP. CONCLUSIONS: GMR for AUC was within the predefined acceptable range of 80-125% for demonstrating equivalence. oPac+E is tolerable and there is no evidence of P-gp induction with repeat administration. With further study, oPac+E could be an alternative to IVP.

Erratum: Lee, R.L.T., et al. Effects of an Unstructured Free Play and Mindfulness Intervention on Wellbeing in Kindergarten Students. Int. J. Environ. Res. Public Health 2020, 17, 5382.

The authors wish to make the following corrections to their paper [...].

Spectroscopic and microscopic examination of teeth exposed to green tea at different temperatures.

Tea is a popular beverage consumed at different temperatures. The effect of tea on teeth at different temperatures has not been studied previously. The present study used an in vitro green tea immersed tooth model at different tea temperatures (hot and cold) compared to an in vivo tea administration model allowing rats to drink tea over the course of a week. The elements present in tea leaves were identified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and compared to the elements in teeth (enamel surface) using Laser-Induced Breakdown Spectroscopy (LIBS). Here, LIBS demonstrated in vivo and in vitro green tea treatments resulted in a significant increase in the mineral elements found in enamel. For the in vitro assessment, elements in enamel varied based on cold-tea and hot-tea treatment; however, hot water reduced the elements in enamel. Atomic force microscopy found the in vivo tea group had a higher roughness average (RA) compared with the in vivo water group. Cold tea and hot tea in vitro groups demonstrated lower RA than in vitro water controls. Scanning electron microscopy found hot water induced cracks more than 1.3µm in enamel while cold tea and hot tea promoted the adhering of extrinsic matter to teeth. Overall, teeth treated to high temperature lost the mineral phase leading to demineralization. Our results indicate that green tea protects enamel, but its protective action in dental structures is enhanced at cold temperature.

Impact of the COVID-19 pandemic on sports and exercise.

BACKGROUND: COVID-19 is a droplet-transmitted potentially fatal coronavirus pandemic affecting the world in 2020. The WHO recommended social distancing and human-to-human contact was discouraged to control the transmission. It has put many countries in a state of lockdown and sporting events (including the 2020 Olympics) have been affected. Participation in sports and exercise, typically regarded as healthy activities, were also debated. The local professional football leagues, governed by the Hong Kong Football Association, ultimately postponed all matches after much deliberation on the transmission risk for the spectators and on-field players. Large spectating crowds are well-known to be infectious hazards, but the infection risk for on-field players is less recognized. Aside from watching professionals exercise, many people opted to hike in the countryside during the weekends to avoid city crowds. This led to a widespread discussion on the issue of wearing a facemask during outdoor activities. METHODS: A small sample of video footage of professional football players were analysed to track each players' time of close body contact and frequency of infection-risky behaviours to investigate the risk of virus transmission during football games.To investigate the physiological effect of wearing a facemask during exercise, we conducted a controlled laboratory, within-subject, repeated measures study of 23 healthy volunteers of various sporting backgrounds. They underwent graded treadmill walking at 4 km per hour for 6 min with and without wearing a surgical mask in a randomized order with sufficient resting time in between trials. The heart rate and the rate of perceived exertion (RPE) were recorded. RESULTS: In a 90 min match, the average duration of close contact between professional football players was 19 min and each player performed an average of 52 episodes of infection-risky behaviours. The heart rate and RPE of subjects wearing a facemask was 128 beats per minute and 12.7 respectively. In those without a facemask, the results were a heart rate of 124 beats per minute and a RPE of 10.8. CONCLUSION: This suggests that the infection risk was high for the players, even without spectators. The laboratory study to investigate the physiological effect of wearing a facemask found that it significantly elevated heart rate and perceived exertion. Those participating in exercise need to be aware that facemasks increase the physiological burden of the body, especially in those with multiple underlying comorbidities. Elite athletes, especially those training for the upcoming Olympics, need to balance and reschedule their training regime to balance the risk of deconditioning versus the risk of infection. The multiple infection-control measures imposed by the Hong Kong national team training centre was highlighted to help strike this balance. Amidst a global pandemic affecting millions; staying active is good, but staying safe is paramount.

Effects of an Unstructured Free Play and Mindfulness Intervention on Wellbeing in Kindergarten Students.

Play is known as the core occupation of young children as it lays a foundation for their early development and physical, emotional and social wellbeing. Literature suggests that unstructured free play and mindfulness interventions may independently promote wellbeing among preschoolers. However, there is no clear evidence of their combination in supporting wellness in early learning environments. We conducted a quasi-experimental study with 42 children aged four to six years, attending two kindergartens in Hong Kong. The intervention included unstructured play with non-directional loose parts (play materials), conducted outdoors for one hour daily followed by a mindfulness intervention for 10 min per day indoors. The intervention lasted for five consecutive days. We examined happiness and aspects of playfulness before and after the intervention, finding a significant increase in all areas. Given greater freedom in play choice, children showed more disruptive behaviors during unstructured play than the control group engaging in recess as usual. We conclude that unstructured play in addition to mindfulness intervention is effective in promoting students' happiness and playfulness, both of which may help maintain mental health and wellbeing amid stressors such as transition and separation. The increased disruptive behavior requires additional investigation.

Breast milk paclitaxel excretion following intravenous chemotherapy-a case report.

Breast cancer can be diagnosed during pregnancy and in the peri-partum period, and the potential exposure of a foetus or neonate to chemotherapy is of concern to mothers and clinicians. Paclitaxel is a commonly used agent in breast cancer, but little is known about its excretion in breast milk. Breastfeeding during chemotherapy has been traditionally cautioned against due to the risk of neonatal exposure to chemotherapy agents, however, data are limited. We measured serum and breast milk concentrations of paclitaxel in a 33-year-old woman with an early breast cancer diagnosed during pregnancy and treated with weekly paclitaxel 80 mg/m2. We found breast milk paclitaxel levels drop below the minimum quantifiable dose at 72 h following chemotherapy, with a relative infant dose of 0.091%. Breast milk excretion of paclitaxel following a dose of 80 mg/m2 is negligible at 72 h, and this may be a safe time to recommence breastfeeding following exposure.

Childhood Obesity and Physical Activity-Friendly School Environments.

OBJECTIVE: Childhood obesity may be related to school environment, but previous studies often focused on food environment only. This study aimed to examine the relationship between school physical activity environment and childhood obesity. STUDY DESIGN: This is a cross-sectional study with multilevel data collected on school physical activity environment using teacher questionnaires, students' growth, and obesity status from electronic health records, and neighborhood socioeconomic status from census data. RESULTS: This study included 208 280 students (6-18 years of age) from 438 schools (45% of Hong Kong). Prevalence of obesity was 5.0%. After controlling for socioeconomic status and intraschool correlation, robust Poisson regression revealed a reduced obesity risk associated with higher teachers' perceived physical activity benefits (risk ratio 0.96, 95% CI 0.94-0.99, P = .02), physical activity teaching experience (0.93, 0.91-0.96, P < .001), school campus size (0.93, 0.87-0.99, P = .02), physical activity ethos (0.91, 0.88-0.94, P < .001), number of physical activity programs (0.93, 0.90-0.96, P < .001), and physical activity facilities (0.87, 0.84-0.90, P < .001). Students in schools with at least 3 physical activity-friendly environmental factors (11.7%) had a much lower risk of obesity (0.68, 0.62-0.75, P < .001) than those without (23.7%). CONCLUSIONS: A physical activity-friendly school environment is associated with lower risk of obesity. School physical activity environment should be considered in future epidemiologic and intervention studies.

A Sports-Based Youth Development Program, Teen Mental Health, and Physical Fitness: An RCT.

OBJECTIVES: To assess the effectiveness of a positive youth development (PYD)-based sports mentorship program on the physical and mental well-being of adolescents recruited in a community setting. METHODS: This is a randomized controlled trial in which we recruited students from 12 secondary schools in Hong Kong, China. Participants were randomly assigned in a 1:1 ratio to an intervention or a control arm after stratification for school from October 2013 to June 2014. Participants were not blinded to allocation because of the nature of the intervention. Students in the intervention arm received an after-school, PYD-based sports mentorship for 18 weeks. Each weekly session lasted 90 minutes. Students in the control arm received exclusive access to a health education Web site. RESULTS: Six hundred and sixty-four students (mean age 12.3 years [SD 0.76]; 386 girls [58.1%]) completed baseline and postintervention assessments. The intervention improved students' mental well-being (Cohen's d, 0.25; 95% confidence interval [CI], 0.10 to 0.40; P = .001), self-efficacy (Cohen's d, 0.22; 95% CI, 0.07 to 0.37; P = .01), resilience (Cohen's d, 0.19; 95% CI, 0.03 to 0.34; P = .02), physical fitness (flexibility [Cohen's d, 0.28; 95% CI, 0.13 to 0.43; P = .02], lower limb muscle strength [Cohen's d, 0.18; 95% CI, 0.03 to 0.33; P = .03], and dynamic balance [Cohen's d, 0.21; 95% CI, 0.06 to 0.37; P = .01]), and physical activity levels (Cohen's d, 0.39; 95% CI, 0.24 to 0.55; P < .0001). The intervention did not significantly improve physical well-being (Cohen's d, -0.01; 95% CI, -0.17 to 0.14; P = .86), BMI z scores (Cohen's d, -0.03; 95% CI, -0.18 to 0.12; P = .69), body fat proportion (Cohen's d, -0.15; 95% CI, -0.31 to 0.00; P = .051), and social connectedness (Cohen's d, -0.03; 95% CI, -0.18 to 0.12; P = .72). CONCLUSIONS: A PYD-based sports mentorship intervention improved healthy adolescents' mental well-being, psychological assets, physical fitness, and physical activity levels.

A redox-controlled electrolyte for plasmonic enhanced dye-sensitized solar cells.

Plasmonic enhanced dye-sensitized solar cells (DSSCs) with metallic nanostructures suffer from corrosion problems, especially with the presence of the iodine/triiodide redox couple in the electrolyte. Herein, we introduce an alternative approach by compensating the corrosion with a modified liquid electrolyte. In contrast to the existing method of surface preservation for plasmonic nanostructures, the redox-controlled electrolyte (RCE) contains iodoaurate intermediates, i.e. gold(i) diiodide (AuI2-) and gold(iii) tetraiodide (AuI4-) with optimal concentrations, such that these intermediates are readily reduced to gold nanoparticles during the operation of DSSCs. As corrosion and redeposition of gold occur simultaneously, it effectively provides corrosion compensation to the plasmonic gold nanostructures embedded in the photoanode. Cycling tests of the specific amount of gold contents in the RCE of DSSCs support the fact that the dissolution and deposition of gold are reversible and repeatable. This gold deposition on the TiO2 photoanode results in forming a Schottky barrier (SB) at the metal-semiconductor interface and effectively inhibits the recombination of electron-hole pairs. Therefore, the RCE increases the short-circuit current, amplifies the open-circuit voltage, and reduces the impedance of the TiO2/dye interface. The power conversion efficiency of DSSCs was improved by 57% after incorporating the RCE.

Complementary Metal Oxide Semiconductor-Compatible, High-Mobility, ⟨111⟩-Oriented GaSb Nanowires Enabled by Vapor-Solid-Solid Chemical Vapor Deposition.

Using CMOS-compatible Pd catalysts, we demonstrated the formation of high-mobility ⟨111⟩-oriented GaSb nanowires (NWs) via vapor-solid-solid (VSS) growth by surfactant-assisted chemical vapor deposition through a complementary experimental and theoretical approach. In contrast to NWs formed by the conventional vapor-liquid-solid (VLS) mechanism, cylindrical-shaped Pd5Ga4 catalytic seeds were present in our Pd-catalyzed VSS-NWs. As solid catalysts, stoichiometric Pd5Ga4 was found to have the lowest crystal surface energy and thus giving rise to a minimal surface diffusion as well as an optimal in-plane interface orientation at the seed/NW interface for efficient epitaxial NW nucleation. These VSS characteristics led to the growth of slender NWs with diameters down to 26.9 ± 3.5 nm. Over 95% high crystalline quality NWs were grown in ⟨111⟩ orientation for a wide diameter range of between 10 and 70 nm. Back-gated field-effect transistors (FETs) fabricated using the Pd-catalyzed GaSb NWs exhibit a superior peak hole mobility of ∼330 cm2 V-1 s-1, close to the mobility limit for a NW channel diameter of ∼30 nm with a free carrier concentration of ∼1018 cm-3. This suggests that the NWs have excellent homogeneity in phase purity, growth orientation, surface morphology and electrical characteristics. Contact printing process was also used to fabricate large-scale assembly of Pd-catalyzed GaSb NW parallel arrays, confirming the potential constructions and applications of these high-performance electronic devices.

Crystal Orientation Controlled Photovoltaic Properties of Multilayer GaAs Nanowire Arrays.

In recent years, despite significant progress in the synthesis, characterization, and integration of various nanowire (NW) material systems, crystal orientation controlled NW growth as well as real-time assessment of their growth-structure-property relationships still presents one of the major challenges in deploying NWs for practical large-scale applications. In this study, we propose, design, and develop a multilayer NW printing scheme for the determination of crystal orientation controlled photovoltaic properties of parallel GaAs NW arrays. By tuning the catalyst thickness and nucleation and growth temperatures in the two-step chemical vapor deposition, crystalline GaAs NWs with uniform, pure ⟨110⟩ and ⟨111⟩ orientations and other mixture ratios can be successfully prepared. Employing lift-off resists, three-layer NW parallel arrays can be easily attained for X-ray diffraction in order to evaluate their growth orientation along with the fabrication of NW parallel array based Schottky photovoltaic devices for the subsequent performance assessment. Notably, the open-circuit voltage of purely ⟨111⟩-oriented NW arrayed cells is far higher than that of ⟨110⟩-oriented NW arrayed counterparts, which can be interpreted by the different surface Fermi level pinning that exists on various NW crystal surface planes due to the different As dangling bond densities. All this indicates the profound effect of NW crystal orientation on physical and chemical properties of GaAs NWs, suggesting the careful NW design considerations for achieving optimal photovoltaic performances. The approach presented here could also serve as a versatile and powerful platform for in situ characterization of other NW materials.

Water resistant CsPbX3 nanocrystals coated with polyhedral oligomeric silsesquioxane and their use as solid state luminophores in all-perovskite white light-emitting devices.

We present an approach towards stable solid-state perovskite based luminophores with different emission colors via surface protection of CsPbX3 (X = Br or I) with a polyhedral oligomeric silsesquioxane (POSS). This treatment results in water resistant perovskite nanocrystal powders, and prevents otherwise easy anion exchange between perovskite nanocrystals of different compositions mixed together in the solid state, which allows us to preserve their distinct emission spectra. We subsequently used mixtures of green-emitting POSS-CsPbBr3 and red-emitting POSS-CsPb(Br/I)3 nanocrystal powders to fabricate single layer all-perovskite down conversion white light-emitting devices.

Approaching the Hole Mobility Limit of GaSb Nanowires.

In recent years, high-mobility GaSb nanowires have received tremendous attention for high-performance p-type transistors; however, due to the difficulty in achieving thin and uniform nanowires (NWs), there is limited report until now addressing their diameter-dependent properties and their hole mobility limit in this important one-dimensional material system, where all these are essential information for the deployment of GaSb NWs in various applications. Here, by employing the newly developed surfactant-assisted chemical vapor deposition, high-quality and uniform GaSb NWs with controllable diameters, spanning from 16 to 70 nm, are successfully prepared, enabling the direct assessment of their growth orientation and hole mobility as a function of diameter while elucidating the role of sulfur surfactant and the interplay between surface and interface energies of NWs on their electrical properties. The sulfur passivation is found to efficiently stabilize the high-energy NW sidewalls of (111) and (311) in order to yield the thin NWs (i.e., <40 nm in diameters) with the dominant growth orientations of ⟨211⟩ and ⟨110⟩, whereas the thick NWs (i.e., >40 nm in diameters) would grow along the most energy-favorable close-packed planes with the orientation of ⟨111⟩, supported by the approximate atomic models. Importantly, through the reliable control of sulfur passivation, growth orientation and surface roughness, GaSb NWs with the peak hole mobility of ∼400 cm(2)V s(-1) for the diameter of 48 nm, approaching the theoretical limit under the hole concentration of ∼2.2 × 10(18) cm(-3), can be achieved for the first time. All these indicate their promising potency for utilizations in different technological domains.