Assessing workload in using electromyography (EMG)-based prostheses.

Using prosthetic devices requires a substantial cognitive workload. This study investigated classification models for assessing cognitive workload in electromyography (EMG)-based prosthetic devices with various types of input features including eye-tracking measures, task performance, and cognitive performance model (CPM) outcomes. Features selection algorithm, hyperparameter tuning with grid search, and k-fold cross-validation were applied to select the most important features and find the optimal models. Classification accuracy, the area under the receiver operation characteristic curve (AUC), precision, recall, and F1 scores were calculated to compare the models' performance. The findings suggested that task performance measures, pupillometry data, and CPM outcomes, combined with the naïve bayes (NB) and random forest (RF) algorithms, are most promising for classifying cognitive workload. The proposed algorithms can help manufacturers/clinicians predict the cognitive workload of future EMG-based prosthetic devices in early design phases.Practitioner summary: This study investigated the use of machine learning algorithms for classifying the cognitive workload of prosthetic devices. The findings suggested that the models could predict workload with high accuracy and low computational cost and could be used in assessing the usability of prosthetic devices in the early phases of the design process.Abbreviations: 3d: 3 dimensional; ADL: Activities for daily living; ANN: Artificial neural network; AUC: Area under the receiver operation characteristic curve; CC: Continuous control; CPM: Cognitive performance model; CPM-GOMS: Cognitive-Perceptual-Motor GOMS; CRT: Clothespin relocation test; CV: Cross validation; CW: Cognitive workload; DC: Direct control; DOF: Degrees of freedom; ECRL: Extensor carpi radialis longus; ED: Extensor digitorum; EEG: Electroencephalogram; EMG: Electromyography; FCR: Flexor carpi radialis; FD: Flexor digitorum; GOMS: Goals, Operations, Methods, and Selection Rules; LDA: Linear discriminant analysis; MAV: Mean absolute value; MCP: Metacarpophalangeal; ML: Machine learning; NASA-TLX: NASA task load index; NB: Naïve Bayes; PCPS: Percent change in pupil size; PPT: Purdue Pegboard Test; PR: Pattern recognition; PROS-TLX: Prosthesis task load index; RF: Random forest; RFE: Recursive feature selection; SHAP: Southampton hand assessment protocol; SFS: Sequential feature selection; SVC: Support vector classifier.

Superior Thermoelectric Performance of SiGe Nanowires Epitaxially Integrated into Thermal Micro-Harvesters.

Semiconductor nanowires have demonstrated fascinating properties with applications in a wide range of fields, including energy and information technologies. Particularly, increasing attention has focused on SiGe nanowires for applications in a thermoelectric generation. In this work, a bottom-up vapour-liquid-solid chemical vapour Deposition methodology is employed to integrate heavily boron-doped SiGe nanowires on thermoelectric generators. Thermoelectrical properties -, i.e., electrical and thermal conductivities and Seebeck coefficient - of grown nanowires are fully characterized at temperatures ranging from 300 to 600 K, allowing the complete determination of the Figure-of-merit, zT, with obtained values of 0.4 at 600 K for optimally doped nanowires. A correlation between doping level, thermoelectric performance, and elemental distribution is established employing advanced elemental mapping (synchrotron-based nano-X-ray fluorescence). Moreover, the operation of p-doped SiGe NWs integrated into silicon micromachined thermoelectrical generators is shown over standalone and series- and parallel-connected arrays. Maximum open circuit voltage of 13.8 mV and power output as high as 15.6 µW cm-2 are reached in series and parallel configurations, respectively, operating upon thermal gradients generated with hot sources at 200 °C and air flows of 1.5 m s-1 . These results pave the way for direct application of SiGe nanowire-based micro-thermoelectric generators in the field of the Internet of Things.

Consenso de expertos sobre la eficacia clínica y directrices sobre la terapia de oxígeno transdérmico continuo para la cicatrización de las heridas complejas o difíciles de cicatrizar.

INTRODUCTION: Oxygen is pivotal for wound healing. Its lack or hypoxia can delay this process, especially in individuals with comorbidities, potentially resulting in complex or hard-to-heal wounds. The Colombian Association of Diabetes (ACD) and the Colombian Association of Internal Medicine (ACMI) collaborated with a diverse group of experts to provide recommendations on the efficacy and best practices of continuous transdermal oxygen therapy (TOTc) in the care of such wounds. METHOD: A modified Delphi technique was employed to obtain controlled feedback and responses. Experts from various disciplines engaged in reviewing and discussing numerous relevant scientific studies, focusing on the role of TOTc in treating chronic ulcers. RESULTS: Continuous transdermal oxygen therapy has proven to be an effective and safe treatment for chronic and/or hard-to-heal ulcers. This therapy directly addresses the wound's oxygen deficiency, providing an environment conducive to healing. Significant benefits were observed, including the acceleration of the healing process, wound size reduction, and an enhancement in patient quality of life. Its efficacy was found across various ulcer etiologies, underscoring its therapeutic versatility. CONCLUSIONS: Continuous transdermal oxygen therapy is effective and safe for treating chronic and hard-to-heal ulcers. It's crucial to address each case individually and through a multidisciplinary approach to maximize this therapy's benefits. Both evidence and clinical experience back its utility across a variety of ulcer etiologies.

RESUMEN: Introducción: El oxígeno es esencial en la cicatrización de heridas. Su ausencia o hipoxia puede retrasar este proceso, especialmente en individuos con comorbilidades, lo que podría resultar en heridas complejas o de difícil cicatrización. La Asociación Colombiana de Diabetes (ACD) y la Asociación Colombiana de Medicina Interna (ACMI) se unieron con un grupo diverso de expertos para brindar recomendaciones sobre la eficacia y práctica de la terapia de oxígeno transdérmico continuo (TOTc) en el cuidado de estas heridas. Método: Se utilizó la técnica Delphi modificada para obtener respuestas y retroalimentación controlada. Expertos de diversas disciplinas participaron en la revisión y discusión de numerosos estudios científicos relevantes, centrados en el papel de la TOTc en el tratamiento de úlceras crónicas. Resultados: El oxígeno transdérmico continuo ha demostrado ser una terapia eficaz y segura en el tratamiento de úlceras crónicas y/o de difícil cicatrización. Esta terapia aborda directamente la deficiencia de oxígeno en la herida, proporcionando un entorno propicio para la curación. Se observaron beneficios significativos, incluyendo aceleración del proceso de cicatrización, reducción del tamaño de la herida y mejora en la calidad de vida del paciente. Se encontró eficacia en diversas etiologías de úlceras, subrayando su versatilidad terapéutica. Conclusiones: La terapia de oxígeno transdérmico continuo es eficaz y segura para tratar úlceras crónicas y de difícil cicatrización. Es vital abordar cada caso de manera individualizada y mediante un enfoque multidisciplinario para maximizar los beneficios de esta terapia. La evidencia y experiencia clínica respaldan su utilidad en diversas etiologías de úlceras. Palabras clave: Terapia de oxígeno transdérmico continuo, Oxígeno, Pie diabético, Cicatrización de heridas, Cuidado de heridas, Úlceras vasculares, Lesiones por presión, Hipoxia, Infección.

Parents' Perception of Barriers to the Comprehensive Management of Children With Cleft Lip and Palate in Bogota, Colombia.

OBJECT: To identify the perception of barriers to the comprehensive management of cleft lip and palate (CLP) by parents/caregivers of Colombian children with this condition. SETTING AND SAMPLE POPULATION: Fifty parents/caregivers of children with CLP under 12 years attending a center specialized in the management of craniofacial congenital conditions in Bogota, Colombia. MATERIALS AND METHODS: This study consisted of 2 phases: a quantitative phase (descriptive cross-sectional) and a qualitative phase (focus group [FG]). Chi-square and Fisher exact tests were used to analyze the association variables. The barriers and alternative ways to overcome barriers were analyzed in the FG. RESULTS: Comprehensive management was mostly defined as access to multiple treatments (54%), and this concept was expanded in the FG toward understanding CLP at all levels. Monoparental families spend their income on treatments (29%) than nuclear families (0%) (P = .001). All parents with high education levels were familiar with healthcare centers specialized in CLP as opposed to 66.7% of parents with basic primary education (P < .05). Regarding the timeliness of appointments, 12.2% of parents earning between 1 and 2 minimum wages reported some kind of difficulty, whereas those earning less than one minimum wage reported difficulties in 66.7% of cases (P = .046). CONCLUSIONS: All participants reported barriers, which increased or decreased depending on their socioeconomic status. The FG allowed the discussion of alternatives to overcome barriers, such as structural, solidarity, and self-management actions.

Spatially and Time-Resolved Carrier Dynamics in Core-Shell InGaN/GaN Multiple-Quantum Wells on GaN Wire.

Time-resolved cathodoluminescence is a key tool with high temporal and spatial resolution. However, optical spectroscopic information can be also extracted using synchrotron pulses in a hard X-ray nanoprobe, exploiting a phenomenon called X-ray excited optical luminescence. Here, with 20 ps time resolution and 80 nm lateral resolution, we applied this time-resolved X-ray microscopy technique to individual core-shell InGaN/GaN multiple quantum well heterostructures deposited on GaN wires. Our findings suggest that the m-plane related multiple quantum well states govern the carrier dynamics. Likewise, our observations support not only the influence of In incorporation in the recombination rates, but also carrier localization phenomena at the hexagon wire apex. In addition, our experiment calls for further investigations of the spatiotemporal domain on the underlying mechanisms of optoelectronic nanodevices. Its great potential becomes more valuable when time-resolved X-ray excited optical luminescence microscopy is used in operando with other methods, such as X-ray absorption spectroscopy.

Verticillium wilt resistant and susceptible olive cultivars express a very different basal set of genes in roots.

BACKGROUND: Olive orchards are threatened by a wide range of pathogens. Of these, Verticillium dahliae has been in the spotlight for its high incidence, the difficulty to control it and the few cultivars that has increased tolerance to the pathogen. Disease resistance not only depends on detection of pathogen invasion and induction of responses by the plant, but also on barriers to avoid the invasion and active resistance mechanisms constitutively expressed in the absence of the pathogen. In a previous work we found that two healthy non-infected plants from cultivars that differ in V. dahliae resistance such as 'Frantoio' (resistant) and 'Picual' (susceptible) had a different root morphology and gene expression pattern. In this work, we have addressed the issue of basal differences in the roots between Resistant and Susceptible cultivars. RESULTS: The gene expression pattern of roots from 29 olive cultivars with different degree of resistance/susceptibility to V. dahliae was analyzed by RNA-Seq. However, only the Highly Resistant and Extremely Susceptible cultivars showed significant differences in gene expression among various groups of cultivars. A set of 421 genes showing an inverse differential expression level between the Highly Resistant to Extremely Susceptible cultivars was found and analyzed. The main differences involved higher expression of a series of transcription factors and genes involved in processes of molecules importation to nucleus, plant defense genes and lower expression of root growth and development genes in Highly Resistant cultivars, while a reverse pattern in Moderately Susceptible and more pronounced in Extremely Susceptible cultivars were observed. CONCLUSION: According to the different gene expression patterns, it seems that the roots of the Extremely Susceptible cultivars focus more on growth and development, while some other functions, such as defense against pathogens, have a higher expression level in roots of Highly Resistant cultivars. Therefore, it seems that there are constitutive differences in the roots between Resistant and Susceptible cultivars, and that susceptible roots seem to provide a more suitable environment for the pathogen than the resistant ones.

Self-Assembly of a Triazolylferrocenyl Dendrimer in Water Yields Nontraditional Intrinsic Green Fluorescent Vesosomes for Nanotheranostic Applications.

The promising field of nanomedicine stimulates a continuous search for multifunctional nanotheranostic systems for imaging and drug delivery. Herein, we demonstrate that application of supramolecular chemistry's concepts in dendritic assemblies can enable the formation of advanced dendrimer-based nanotheranostic devices. A dendrimer bearing 81 triazolylferrocenyl terminal groups adopts a more compact shell-like structure in polar solvents with the ferrocenyl peripheral groups backfolding toward the hydrophobic dendrimer interior, while exposing the more polar triazole moieties as the dendritic shell. Akin to lipids, the compact dendritic structure self-assembles into uniform nanovesicles that in turn self-assemble into larger vesosomes in water. The vesosomes emit green nontraditional intrinsic fluorescence (NTIL), which is an emerging property as there are no classical fluorophores in the dendritic macromolecular structure. This work confirms the hypothesis that the NTIL emission is greatly enhanced by rigidification of the supramolecular assemblies containing heteroatomic subluminophores (HASLs) and by the presence of electron rich functional groups on the periphery of dendrimers. This work is the first one detecting NTIL in ferrocenyl-terminated dendrimers. Moreover, the vesosomes are stable in biological medium, are uptaken by cells, and show cytotoxic activity against cancer cells. Accordingly, the self-organization of these dendrimers into tertiary structures promotes the emergence of new properties enabling the same component, in this case, ferrocenyl group, to function as both antitumoral drug and fluorophore.

Remote Doping of Scalable Nanowire Branches.

Selective-area epitaxy provides a path toward high crystal quality, scalable, complex nanowire networks. These high-quality networks could be used in topological quantum computing as well as in ultrafast photodetection schemes. Control of the carrier density and mean free path in these devices is key for all of these applications. Factors that affect the mean free path include scattering by surfaces, donors, defects, and impurities. Here, we demonstrate how to reduce donor scattering in InGaAs nanowire networks by adopting a remote-doping strategy. Low-temperature magnetotransport measurements indicate weak anti-localization-a signature of strong spin-orbit interaction-across a nanowire Y-junction. This work serves as a blueprint for achieving remotely doped, ultraclean, and scalable nanowire networks for quantum technologies.

The Metallocene Battery: Ultrafast Electron Transfer Self Exchange Rate Accompanied by a Harmonic Height Breathing.

The first all-metallocene rechargeable battery consisting of poly-cobaltocenium/- and poly-ferrocene/reduced graphene oxide composites as anode and cathode was prepared. The intrinsically fast ET self-exchange rate of metallocenes was successfully combined with an efficient ion-percolation achieved by molecular self-assembly. The resulting battery materials show ideal Nernstian behavior, is thickness scalable up to >1.2 C cm-2 , and exhibit high coulombic efficiency at ultrafast rates (200 A g-1 ). Using aqueous LiClO4 , the charge is carried exclusively by the anion. The ClO4 - intercalation is accompanied by a reciprocal height change of the active layers. Principally, volume changes in organic battery materials during charging/discharging are not desirable and represent a major safety issue. However, here, the individual height changes-due to ion breathing-are reciprocal and thus prohibiting any internal pressure build-up in the closed-cell, leading to excellent cycling stability.

A helium mini-cryostat for the nanoprobe beamline ID16B at ESRF: characteristics and performance.

A helium mini-cryostat has been developed for the hard X-ray nanoprobe ID16B of the European Synchrotron to collect X-ray excited optical luminescence and X-ray fluorescence at low temperature (<10 K). The mini-cryostat has been specifically designed to fit within the strong space restrictions and high-demanding mechanical constraints imposed by the beamline to provide vibration-free operation and maximal thermal stability. This paper reports the detailed design, architecture and technical requirements of the mini-cryostat, and presents the first experimental data measured using the cryogenic equipment. The resulting cryo-system features ultimate thermal stability, fast cool-down and ultra-low vibrations. The simultaneous X-ray fluorescence and X-ray excited optical luminescence data acquired from bulk GaN and core/shell InGaN/GaN multi-quantum wells validated the excellent performance of the cryostat with ultimate resolution, stability and sensitivity.

MEGARes: an antimicrobial resistance database for high throughput sequencing.

Antimicrobial resistance has become an imminent concern for public health. As methods for detection and characterization of antimicrobial resistance move from targeted culture and polymerase chain reaction to high throughput metagenomics, appropriate resources for the analysis of large-scale data are required. Currently, antimicrobial resistance databases are tailored to smaller-scale, functional profiling of genes using highly descriptive annotations. Such characteristics do not facilitate the analysis of large-scale, ecological sequence datasets such as those produced with the use of metagenomics for surveillance. In order to overcome these limitations, we present MEGARes (https://megares.meglab.org), a hand-curated antimicrobial resistance database and annotation structure that provides a foundation for the development of high throughput acyclical classifiers and hierarchical statistical analysis of big data. MEGARes can be browsed as a stand-alone resource through the website or can be easily integrated into sequence analysis pipelines through download. Also via the website, we provide documentation for AmrPlusPlus, a user-friendly Galaxy pipeline for the analysis of high throughput sequencing data that is pre-packaged for use with the MEGARes database.

Spermatogonial stem cells identified by molecular expression of PLZF, integrin ß1 and reactivity to Dolichos biflorus agglutinin in alpaca adult testes.

The identification system of spermatogonial stem cell (SSC) was established in alpaca using the molecular expression as well as the reactivity pattern to Dolichos biflorus agglutinin (DBA) by flow cytometry. Twenty-four testicles with their epididymis were recovered from adult alpacas at the slaughterhouse of Huancavelica-Perú. Samples were transported to the Laboratory of Reproductive Physiology at Universidad Nacional Mayor de San Marcos. Testes were selected for our study when the progressive motility of epididymal spermatozoa (ESPM) was above 30%. Isolation of SSC was performed with two enzymatic digestions. Finally, sperm viability was evaluated by means of the trypan blue vital stain in spermatogonial round cells. Samples with more than 80% viability were selected. Isolated cells cultured for 2 days were used for identifying the presence of SSCs by the expression of integrin ß1 (116 bp) and PLZF (206 bp) genes. Spermatogonia were classified according to the DBA reactivity. Spermatogonia with a strong positive to DBA (sDBA+ ) were classified as SSC (Mean ± SEM=4.44 ± 0.68%). Spermatogonia in early differentiation stages stained weakly positive with DBA (wDBA+ ) (Mean ± SEM=37.44 ± 3.07%) and differentiated round cells as DBA negative (Mean ± SEM=54.12 ± 3.18%). With the use of molecular and DBA markers, it is possible to identify easily the spermatogonial stem cells in alpaca.

Transcriptomic time-series analysis of early development in olive from germinated embryos to juvenile tree.

BACKGROUND: Despite its relevance, almost no studies account for the genetic control in the early stages of tree development, i.e. from germination on. This study seeks to make a quite complete transcriptome for olive development and to elucidate the dynamic regulation of the transcriptomic response during the early-juvenile period by RNAseq time-series expression analysis. The transcriptome was made from 342,049,597 paired-end reads of 101 bp in length. The assembled transcriptome contained 109,125 unigenes (N50 = 1490 bp, average length = 839). RESULTS: The time-series-expression analysis showed that, embryonic structures present at the first month after the induction of germination reached a more differentiated state in two-month-old seedlings. Once the plants were between three and four months old and reached a size around 6-7 nodes, the first developmental stages appeared to be complete and the developing seedling became a juvenile plant. In addition, an AGL-gene was rapidly downregulated during the induction of germination. The repression of this gene was very strong, as evidenced by the low levels of gene expression during plant development from the embryonic seedling to undetectable levels of expression in the adult tree. These results suggest that this gene may be involved in seed dormancy and could be a repressor of the germination. Also, an APL1-like olive gene was found to be expressed at high levels during flowering, and was also expressed during the cold incubation in the activation of embryo germination, suggesting a probable role in embryonic development. CONCLUSIONS: The early development from germination to the juvenile stage of olive seedlings occurred when plants reached a size around 6-7 nodes, and general changes of relevant groups of genes involved in development are described. An AGL-gene was proposed to be involved in germination repression. An APL1-like gene was found to have a probable role in embryonic development.

Highly Selective and Sharp Volcano-type Synergistic Ni2Pt@ZIF-8-Catalyzed Hydrogen Evolution from Ammonia Borane Hydrolysis.

Ammonia borane hydrolysis is considered as a potential means of safe and fast method of H2 production if it is efficiently catalyzed. Here a series of nearly monodispersed alloyed bimetallic nanoparticle catalysts are introduced, optimized among transition metals, and found to be extremely efficient and highly selective with sharp positive synergy between 2/3 Ni and 1/3 Pt embedded inside a zeolitic imidazolate framework (ZIF-8) support. These catalysts are much more efficient for H2 release than either Ni or Pt analogues alone on this support, and for instance the best catalyst Ni2Pt@ZiF-8 achieves a TOF of 600 molH2·molcatal-1·min-1 and 2222 molH2·molPt-1·min-1 under ambient conditions, which overtakes performances of previous Pt-base catalysts. The presence of NaOH boosts H2 evolution that becomes 87 times faster than in its absence with Ni2Pt@ZiF-8, whereas NaOH decreases H2 evolution on the related Pt@ZiF-8 catalyst. The ZIF-8 support appears outstanding and much more efficient than other supports including graphene oxide, active carbon and SBA-15 with these nanoparticles. Mechanistic studies especially involving kinetic isotope effects using D2O show that cleavage by oxidative addition of an O-H bond of water onto the catalyst surface is the rate-determining step of this reaction. The remarkable catalyst activity of Ni2Pt@ZiF-8 has been exploited for successful tandem catalytic hydrogenation reactions using ammonia borane as H2 source. In conclusion the selective and remarkable synergy disclosed here together with the mechanistic results should allow significant progress in catalyst design toward convenient H2 generation from hydrogen-rich substrates in the close future.

Tolerance of olive (Olea europaea) cv Frantoio to Verticillium dahliae relies on both basal and pathogen-induced differential transcriptomic responses.

Verticillium wilt of olive (VWO) is one of the most serious biotic constraints for this tree crop. Our knowledge of the genetics of the tolerance/resistance to this disease is very limited. Here we show that tolerance of the cv Frantoio relies on both basal and early pathogen-induced differential transcriptomic responses. A comparative transcriptomic analysis (RNA-seq) was conducted in root tissues of cvs Frantoio (VWO-tolerant) and Picual (VWO-susceptible). RNA samples originated from roots of inoculated olive plants during the early infection stages by Verticillium dahliae (highly virulent, defoliating pathotype). A huge number of differentially expressed genes (DEGs) were found between 'Frantoio' and 'Picual' (27 312 unigenes) in the absence of the pathogen. Upon infection with V. dahliae, 'Picual' and 'Frantoio' plants responded differently too. In the early infection stages, four clusters of DEGs could be identified according to their time-course expression patterns. Among others, a pathogenesis-related protein of the Bet v I family and a dirigent-like protein involved in lignification, and several BAK1, NHL1, reactive oxygen species stress response and BAM unigenes showed noticeable differences between cultivars. Tolerance of 'Frantoio' plants to VWO is a consequence of a complex and multifaceted process which involves many plant traits.

Electron- and Hydride-Reservoir Organometallics as Precursors of Catalytically Efficient Transition Metal Nanoparticles in Water.

Nanoparticles (NPs) are actively investigated for their efficient use in catalysis, but their means of synthesis is a key factor influencing their catalytic properties owing to surface coverage with byproducts. Here, neutral electron- and hydride-rich late transition metal organometallics are compared for the synthesis of late transition metal NPs in the presence of poly(vinylpirolidone) (PVP). In particular, the effect of electron-reservoir donors, hydride-reservoir donors, and electron-rich dimers yielding NPs electrostatically stabilized by cationic organometallics are compared in terms of NP size and catalytic efficiency. The catalytic reactions scrutinized with excellent results include 4-nitrophenol reduction to 4-aminophenol by NaBH4 for the AuNPs and PdNPs, and Suzuki-Miyaura reactions for the PdNPs. The nature of the reductant has more influence on the NP size in the case of AuNPs than PdNPs, and the best NP catalysts are obtained with hydride-reservoir complexes as reductants. The less bulky hydride donors are superior, with the complex [CoCp(ŋ4 -C5 H6 )] (Cp=ŋ5 -C5 H5 ) giving the NPs with the best catalyst efficiencies for both reactions. Protection of the NP cores by the organometallic sandwich salt is found to be the key to catalytic efficiency.

Electron Flow in Large Metallomacromolecules and Electronic Switching of Nanoparticle Stabilization: Click Ferrocenyl Dentromers that Reduce AuIII to Au Nanoparticles.

Click ferrocenyl-terminal dentromers, a family of arene-cored dendrimers with triple branching (9-Fc, 27-Fc, 81-Fc, and 243-Fc), reduce AuIII to ferricinium dentromer-stabilized Au nanoparticles (AuNPs). Cyclic voltammetry studies in CH2 Cl2 show reversible CV waves with some adsorption for the 243-Fc dentromer and the number of redox groups found, 255±25, by using the Bard-Anson method, is close to the theoretical number of 243. The dentromers reduce aqueous HAuCl4 to water-soluble ferricinium chloride dentromer-stabilized AuNPs with core sizes between 30 and 47 nm. These triazolylferricinium dentromer-stabilized AuNPs are reduced by cobaltocene to cobalticinium chloride and ferrocene dentromer weakly stabilized AuNPs together with a redshift of the AuNP plasmon. The weakness of the AuNP stabilization is characterized by dentromer extraction with CH2 Cl2 along with irreversible AuNP agglomeration for the 9, 27, and 81-ferrocenyl dentromer, with only the 243-ferrocenyl dentromer-AuNP withstanding this process. Altogether, this demonstrates the electronic switching of the dentromer-mediated AuNP stabilization.

Dentromers, a Family of Super Dendrimers with Specific Properties and Applications.

Dentromers (from dentro, δεντρο: tree in Greek), and meros (µÎµροσ, in greek: part) are introduced as a family of dendrimers constructed according to successive divergent 1 → 3 branching. The smaller dentromers have 27 terminal branches. With alcohol termini they were originally named arborols by Newkome, who pioneered 1 → 3 constructions of dendrimers and dendrons. Giant dentromers have been constructed and decorated in particular with ferrocene and other redox active groups. The synthesis, specific properties, and applications are examined in this mini review article dedicated to Don Tomalia, with an emphasis on dense peripheral packing favoring the functions of encapsulation, redox sensing, and micellar template for catalysis in water and aqueous solvents.

Tetrablock Metallopolymer Electrochromes.

Multi-block polymers are highly desirable for their addressable functions that are both unique and complementary among the blocks. With metal-containing polymers, the goal is even more challenging insofar as the metal properties may considerably extend the materials functions to sensing, catalysis, interaction with metal nanoparticles, and electro- or photochrome switching. Ring-opening metathesis polymerization (ROMP) has become available for the formation of living polymers using highly efficient initiators such as the 3rd generation Grubbs catalyst [RuCl2 (NHC)(=CHPh)(3-Br-C5 H4 N)2 ], 1. Among the 24 possibilities to introduce 4 blocks of metallopolymers into a tetrablock metallocopolymer by ROMP using the catalyst 1, two viable pathways are disclosed. The synthesis, characterization, electrochemistry, electron-transfer chemistry, and remarkable electrochromic properties of these new nanomaterials are presented.

Hydrolysis of Ammonia-Borane over Ni/ZIF-8 Nanocatalyst: High Efficiency, Mechanism, and Controlled Hydrogen Release.

Non-noble metal nanoparticles are notoriously difficult to prepare and stabilize with appropriate dispersion, which in turn severely limits their catalytic functions. Here, using zeolitic imidazolate framework (ZIF-8) as MOF template, catalytically remarkably efficient ligand-free first-row late transition-metal nanoparticles are prepared and compared. Upon scrutiny of the catalytic principles in the hydrolysis of ammonia-borane, the highest total turnover frequency among these first-row late transition metals is achieved for the templated Ni nanoparticles with 85.7 molH2 molcat-1 min-1 at room temperature, which overtakes performances of previous non-noble metal nanoparticles systems, and is even better than some noble metal nanoparticles systems. Mechanistic studies especially using kinetic isotope effects show that cleavage by oxidative addition of an O-H bond in H2O is the rate-determining step in this reaction. Inspired by these mechanistic studies, an attractive and effective "on-off" control of hydrogen production is further proposed.