Superhard transparent hybrid nanocomposites for high fidelity UV-nanoimprint lithography

Transparent hyperbranched acrylate nanocomposites were produced using different combinations of silica nanoparticles and silicon-based sol-gel precursors. The nanocomposites were processed using a dual-cure UV polymerization and condensation scheme. The viscosity of hybrid suspensions was found to be one to two orders of magnitude lower than that of particulate composites with the same equivalent silica fraction. The Vickers microhardness of the polymer was 112 MPa. It was equal to 190 MPa and 148 MPa for the hybrid composites and particulate composites with 20 vol% SiO2, respectively, and it was equal to 287 MPa for the hybrid material with 30 vol% SiO2. Light-trapping textures in the form of random sub-micron pyramidal features were replicated in the hybrid composites from a nickel template using UV-nanoimprint lithography. After optimization of the dual-cure process sequence, a very high replication fidelity was obtained for all investigated compositions, leading to a haze above 99% over the visible light spectrum and a very effective light scattering performance in a broad angular exposure. (C) 2013 Elsevier Ltd. All rights reserved

Responsive Neurostimulation for People With Drug-Resistant Epilepsy and Autism Spectrum Disorder

PURPOSE: Individuals with autism spectrum disorder (ASD) have comorbid epilepsy at much higher rates than the general population, and about 30% will be refractory to medication. Patients with drug-resistant epilepsy (DRE) should be referred for surgical evaluation, yet many with ASD and DRE are not resective surgical candidates. The aim of this study was to examine the response of this population to the responsive neurostimulator (RNS) System. METHODS: This multicenter study evaluated patients with ASD and DRE who underwent RNS System placement. Patients were included if they had the RNS System placed for 1 year or more. Seizure reduction and behavioral outcomes were reported. Descriptive statistics were used for analysis. RESULTS: Nineteen patients with ASD and DRE had the RNS System placed at 5 centers. Patients were between the ages of 11 and 29 (median 20) years. Fourteen patients were male, whereas five were female. The device was implanted from 1 to 5 years. Sixty-three percent of all patients experienced a \u3e50% seizure reduction, with 21% of those patients being classified as super responders (seizure reduction \u3e90%). For the super responders, two of the four patients had the device implanted for \u3e2 years. The response rate was 70% for those in whom the device was implanted for \u3e2 years. Improvements in behaviors as measured by the Clinical Global Impression Scale-Improvement scale were noted in 79%. No complications from the surgery were reported. CONCLUSIONS: Based on the authors\u27 experience in this small cohort of patients, the RNS System seems to be a promising surgical option in people with ASD-DRE

Influence of the thickness of a nanometric copper interlayer on Au/dielectric thermal boundary conductance

The influence of the thickness of a thin (1.5-30 nm) copper layer on the thermal boundary conductance (TBC) at the interface between gold and silicon, sapphire and diamond, respectively, was studied using Time Domain Thermoreflectance. Overall, a monotonic increase in the TBC was observed over the first 10 nm, before reaching a plateau. In some cases, it was also observed that an interlayer reduces the TBC as compared to the reference system. This is rationalized by assuming that the TBC evolution as a function of the interlayer thickness is controlled by (i) a contribution of the gold layer that has to be taken into account for all phonons having a wavelength larger than the interlayer thickness and (ii) a thickness-dependent resistance within the interlayer that appears when the electron-phonon coupling is incomplete, i.e., typically over the first 10 nm. A model is proposed in which the contribution to thermal boundary conductance by phonons coming directly from the gold layer is estimated using a simple Debye approximation, while the resistance that appears within the interlayer is estimated by g(T) times h with g(T) the electron-phonon coupling factor and h the interlayer thickness. This results in a system with three resistances in series, i.e., the metal-metal and metal-dielectric interfacial resistances and the interlayer resistance, and a contribution due to phonons of the gold layer. A reasonably good agreement between this model and experimental data is observed. Published by AIP Publishing

Influence of interfacial structural disorder and/or chemical interdiffusion on thermal boundary conductance for Ti/Si and Au/Si couples

This work aims at experimentally assessing the effect of structural disorder and/or chemical interdiffusion on thermal boundary conductance (TBC) at metal/dielectric interfaces. To this end, the TBC of Au/Si and Ti/Si interfaces was measured by time domain thermoreflectance in the as-deposited state and after various heat treatments. Transmission electron microscopy (TEM) was used to determine the structure of the interface for each heat treatment condition. The TBC at the Au/Si interface was found to be highest in the as-deposited state and to be somewhat reduced after heat treatments. TEM images showed that the highest TBC was obtained when the interface contained a disordered transition layer with some degree of interdiffusion as present in the as-deposited state. Heat treatments led to the separation of species and to more abrupt interfaces with lower TBC. Whether this change in TBC was linked to disorder or to interdiffusion could not be distinguished. The TBC at the Ti/Si interfaces was observed to decrease with the heat treatment duration. TEM investigations revealed the presence of a thin disordered layer that did not evolve much with heat treatments. The evolution of the TBC was hence rationalized by interdiffusion facilitated by heat treatments that most likely modified the diffusion zone thickness and chemical composition, as well as the disordered layer's chemical composition. These changes result in modified interfacial properties, which ultimately affect the TBC. A quantitative exploration of the TBC dependence on the composition was not possible in this work, due to the extreme thinness of the regions under consideration preventing any reliable STEM-energy dispersive x-ray measurement. Published under license by AIP Publishing

Towards a coherent database of thermal boundary conductance at metal/dielectric interfaces

The thermal boundary conductance (TBC) of metal/dielectric couples was measured for a large variety of metals on silicon, sapphire, and diamond using time domain thermoreflectance and compared to data previously obtained on diamond. In the case of silicon, HF-cleaned and RF-etched surfaces were tested. The detailed structure of these interfaces was studied, allowing distinction of two different cases of M/Si couples: (i) some amount of interfacial reaction exists for both surface terminations, resulting in similar TBCs; and (ii) chemically abrupt interfaces are achieved, resulting in TBC values that are always lower for RF-etched samples. The TBC values obtained on different substrates allowed identifying a tendency of the TBC to scale with the maximum transmission limit. A possible influence of the substrate was evaluated using both the diffuse mismatch model (DMM), which predicts a strong dependence on the substrate properties, and a newly developed approach based on the metal irradiance (IM), which predicts no dependence on the substrate properties. The DMM was implemented using a Debye model with either a linear (DMMLinear) or a Sine-Type (DMMSineType) dispersion, while the IM was implemented using a Sine-Type (IMSineType) dispersion. The DMMLinear and the IMSineType were found to be more suitable than the DMMSineType and to be equally precise in predicting TBC at metal/silicon and metal/sapphire interfaces. The IMSineType is found to be better suited than both the DMMLinear and the DMMSineType to predict TBC at metal/diamond interfaces. IMSineType being the only model tested that is suitable for all three substrates, it appears to be the most appropriate choice. As a corollary, we find that the TBC dependence on substrate properties is much weaker than predicted by the DMM

Development of a new family of phosphorous-free Pt-based bulk metallic glasses

New BMGs exhibiting strong glass forming ability combined with high hardness have been developed based on the Pt-Si-B ternary system. The effects of partial substitution of platinum by transition metals of the group iron, cobalt, nickel, and copper, as well as the partial replacement of silicon by germanium on the melting temperature, T-m, the crystallization temperature, T-x, the glass transition temperature, T-g, and the hardness are investigated. Amongst the transition metals, nickel and copper were found to reduce the liquidus and the solidus temperatures of the Pt-Si-B near ternary eutectic composition, while cobalt and iron had no influence on the solidus temperature but raised the liquidus temperature significantly. Substitution of one fourth of platinum atoms by either nickel or copper increased the glass transition temperature by roughly 45 K and 65 K, respectively, with a concomitant increase in crystallization temperature of similar magnitude. For a series of alloys with the general formula (Pt0.75Cu0.25)(66.6)B24Si9.4-xGex, increasing substitution of silicon by germanium (x = 0...3) led to a significantly increased crystallization temperature essentially by shifting the first of typically two crystallization peaks to higher temperatures, while the T-g was slightly lowered as x increased. This resulted in a marked widening of the supercooled liquid region, Delta T. Within this alloying series a general trend of increased hardness with increased T-g was observed. (C) 2016 Elsevier B.V. All rights reserved

Role of the electron-phonon coupling on the thermal boundary conductance of metal/diamond interfaces with nanometric interlayers

Thermal boundary conductance (TBC) of the Ag/diamond and Au/diamond interfaces with a nanometer-thick interface layer of either nickel or molybdenum is measured by time domain thermoreflectance and modeled based on a 3-layer two-temperature model (3l-TTM). The rationale for this study is to critically assess the role of the electron-phonon coupling factor of the interlayer along with its thickness on the TBC. It is shown that the TBC of both systems rapidly increases with the interlayer thickness until reaching a stable plateau for thicknesses greater than 1.5 nm. The plateau average value is 15%-25% lower than the intrinsic TBC between the interlayer material and the diamond substrate. This behavior and values of the TBC of both systems are in good agreement with the predictions of the 3l-TTM. The predictability of this model is also analyzed for a Cu interlayer inserted at Au/silicon interfaces with thicknesses ranging from 1.5 to 20 nm. While the room temperature TBC of this system is well described by the 3l-TTM, the values measured at 80 K can only be predicted by the 3l-TTM, provided that the interlayer electron-phonon coupling factor is reduced by a factor of 2, as was experimentally observed for Ag and Au. The obtained experimental results along with the proposed model can thus be useful for tailoring the TBC of metallic interfaces in a wide range of temperatures. Published under license by AIP Publishing

Part-time employment: a comparative analysis of Spain and the Netherlands

Part-time employment, Discrimination, Gender differences, Multinomial logit, J22, J71, K31, K33,

Desmoplastic small round cell tumors : Multimodality treatment and new risk factors

Background: To evaluate optimal therapy and potential risk factors. Methods: Data of DSRCT patients <40 years treated in prospective CWS trials 1997‐2015 were analyzed. Results: Median age of 60 patients was 14.5 years. Male:female ratio was 4:1. Tumors were abdominal/retroperitoneal in 56/60 (93%). 6/60 (10%) presented with a localized mass, 16/60 (27%) regionally disseminated nodes, and 38/60 (63%) with extraperitoneal metastases. At diagnosis, 23/60 (38%) patients had effusions, 4/60 (7%) a thrombosis, and 37/54 (69%) elevated CRP. 40/60 (67%) patients underwent tumor resection, 21/60 (35%) macroscopically complete. 37/60 (62%) received chemotherapy according to CEVAIE (ifosfamide, vincristine, actinomycin D, carboplatin, epirubicin, etoposide), 15/60 (25%) VAIA (ifosfamide, vincristine, adriamycin, actinomycin D) and, 5/60 (8%) P6 (cyclophosphamide, doxorubicin, vincristine, ifosfamide, etoposide). Nine received high‐dose chemotherapy, 6 received regional hyperthermia, and 20 received radiotherapy. Among 25 patients achieving complete remission, 18 (72%) received metronomic therapies. Three‐year event‐free (EFS) and overall survival (OS) were 11% (±8 confidence interval [CI] 95%) and 30% (±12 CI 95%), respectively, for all patients and 26.7% (±18.0 CI 95%) and 56.9% (±20.4 CI 95%) for 25 patients achieving remission. Extra‐abdominal site, localized disease, no effusion or ascites only, absence of thrombosis, normal CRP, complete tumor resection, and chemotherapy with VAIA correlated with EFS in univariate analysis. In multivariate analysis, significant factors were no thrombosis and chemotherapy with VAIA. In patients achieving complete remission, metronomic therapy with cyclophosphamide/vinblastine correlated with prolonged time to relapse. Conclusion: Pleural effusions, venous thrombosis, and CRP elevation were identified as potential risk factors. The VAIA scheme showed best outcome. Maintenance therapy should be investigated further