Resistive-switching behavior in polycrystalline CaCu(3)Ti(4)O(12) nanorods

Highly aligned CaCu(3)Ti(4)O(12) nanorod arrays were grown on Si/SiO(2)/Ti/Pt substrates by radio-frequency sputtering at a low deposition temperature of 300 °C and room temperature. Structural and morphological studies have shown that the nanostructures have a polycrystalline nature and are oriented perpendicular to the substrate. The high density of grain boundaries in the nanorods is responsible for the nonlinear current behavior observed in these arrays. The current-voltage (I-V) characteristics observed in nanorods were attributed to the resistive memory phenomenon. The electrical resistance of microcapacitors composed of CaCu(3)Ti(4)O(12) nanorods could be reversibly switched between two stable resistance states by varying the applied electric field. In order to explain this switching mechanism, a model based on the increase/decrease of electrical conduction controlled by grain boundary polarization has been proposed.     

The results of the Ravitch-Sutherland technic for surgical correction in pectus excavatum

The aim of our study was to asses the functional and cosmetic results after performing a modified Ravitch-Sutherland procedure in children presenting with pectus excavatum. A series of 31 children with ages ranging between 5 and 16 years, presenting with pectus excavatum, were operated between 1986-1996 in our service. In 5 cases surgical treatment was required by the presence of respiratory and/or cardiac functional impairment due to the malformation. In the other 23 cases operation was performed mainly for cosmetic reasons. In all cases a modified Ravitch-Sutherland procedure was performed. Modifications consisted in renouncing at the plication of the perichondrium and in associating a diaphragmatic elongation and Bedouelle laparoplasty in all cases. Longitudinal sternotomy was performed in 2 cases with severely impaired ventilatory capacity. Functional and cosmetic results were good in all cases. In 2 cases, in which recurrence of the condition was observed, a second identical procedure was performed, with a good result. The interval between the operation and the moment of long-term evaluation ranged between 3 months and 11 years. We conclude that the modified Ravitch-Sutherland procedure represents an effective method for the treatment of pectus excavatum cases, offering good functional and cosmetic long-term results.     

Considerations for the Design of Intercepting Drainage for Collecting Water from Seep Areas

Springs that appear at multiple sites on sloping lands and create problems of excess soil moisture and reduced crop yield require the implementation of a network of intercepting drains. The water removed by the intercepting drains also needs to be conducted to a collecting shaft or main drain, whereby it can be safely utilized or discharged back to a lower-lying position in the landscape. In this paper, we present a design method for establishing the position of the first row of interceptor drains and the number of successive rows of intercepting drains, as well as the distances between them. The first row of intercepting drains must be placed upstream of the upper limit of the wet area, through those points at which water-bearing material is found at 40–50?cm underground. The number of rows of necessary intercepting drains is determined from the ratio between the thickness of water-bearing material and the thickness of the filter+drain. For multiple springs that are concentrated on the surface of sloping lands, we propose the solution of a collecting chamber with a side drain and bottom filter.     

Dysbiosis in the Development of Type I Diabetes and Associated Complications: From Mechanisms to Targeted Gut Microbes Manipulation Therapies

Globally, we are facing a worrying increase in type 1 diabetes mellitus (T1DM) incidence, with onset at younger age shedding light on the need to better understand the mechanisms of disease and step-up prevention. Given its implication in immune system development and regulation of metabolism, there is no surprise that the gut microbiota is a possible culprit behind T1DM pathogenesis. Additionally, microbiota manipulation by probiotics, prebiotics, dietary factors and microbiota transplantation can all modulate early host–microbiota interactions by enabling beneficial microbes with protective potential for individuals with T1DM or at high risk of developing T1DM. In this review, we discuss the challenges and perspectives of translating microbiome data into clinical practice. Nevertheless, this progress will only be possible if we focus our interest on developing numerous longitudinal, multicenter, interventional and double-blind randomized clinical trials to confirm their efficacy and safety of these therapeutic approaches.     

Low-Temperature Sputtering Deposition of Aligned Polycrystalline CaCu3Ti4O12 Nanorods

Vertically aligned polycrystalline CaCu₃Ti₄O₁₂ nanorods were obtained by rf sputtering at low substrate temperatures. The rods grow by electrostatic attraction and aggregation of charged clusters, independently of the substrate used. These nanostructures exhibit a strong nonlinear current × voltage behavior and high losses during cyclic testing, indicating a combination of Schottky's barrier and Joule's heating effects.     

Development of New Collagen/Clay Composite Biomaterials

The fabrication of collagen-based biomaterials for skin regeneration offers various challenges for tissue engineers. The purpose of this study was to obtain a novel series of composite biomaterials based on collagen and several types of clays. In order to investigate the influence of clay type on drug release behavior, the obtained collagen-based composite materials were further loaded with gentamicin. Physiochemical and biological analyses were performed to analyze the obtained nanocomposite materials after nanoclay embedding. Infrared spectra confirmed the inclusion of clay in the collagen polymeric matrix without any denaturation of triple helical conformation. All the composite samples revealed a slight change in the 2-theta values pointing toward a homogenous distribution of clay layers inside the collagen matrix with the obtaining of mainly intercalated collagen-clay structures, according X-ray diffraction analyses. The porosity of collagen/clay composite biomaterials varied depending on clay nanoparticles sort. Thermo-mechanical analyses indicated enhanced thermal and mechanical features for collagen composites as compared with neat type II collagen matrix. Biodegradation findings were supported by swelling studies, which indicated a more crosslinked structure due additional H bonding brought on by nanoclays. The biology tests demonstrated the influence of clay type on cellular viability but also on the antimicrobial behavior of composite scaffolds. All nanocomposite samples presented a delayed gentamicin release when compared with the collagen-gentamicin sample. The obtained results highlighted the importance of clay type selection as this affects the performances of the collagen-based composites as promising biomaterials for future applications in the biomedical field.     

Physical properties and cure characteristics of natural rubber/nanoclay composites with two different compatibilizers

The effects of epoxidized natural rubber (ENR) and maleic anhydride‐grafted polybutadiene (PB‐g‐MA) as compatibilizers to rubber formulations with and without organo‐modified layered silicates are investigated. The physical properties and curing characteristics of composites are studied by moving die rheometer, rubber process analyzer, tensile, tear, and hardness testing. The state of organoclay intercalation was determined by X‐ray diffraction method. The addition of compatibilizers, especially ENR 50, results in further intercalation or exfoliation of the organoclay that increased the clay dispersion in the rubber matrix. ENR 50 with organo‐modified clay improves the physical properties and changes the curing profile. The addition of PB‐g‐MA without organoclay increases the tensile strength (σ_max) by increasing the stock viscosity of the rubber compound. Interestingly, simultaneous increase in hardness and σ_max is achieved in the presence of both compatibilizers, a characteristic that is difficult to achieve and sometimes required in rubber processing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Single mode optical fiber coupling to a laser diode

A double ball lens coupling scheme has been designed. The efficiency of the coupling has been tested. The effect of the lateral and transversal offset on the coupling efficiency has been investigated. Two spherical lenses based on As₂S₃ and As₂Se₃ have been used to this purpose. We used a Roithner RLT7605MG 5 mW single mode laser diode as source. The variation of the coupling with the working distance has been measured and an optimum separation distance has been found. The article is published in the original.     

Structured ZnO-based contacts deposited by non-reactive rf magnetron sputtering on ultra-thin SiO2/Si through a stencil mask

In this paper, we study the localized deposition of ZnO micro and nanostructures deposited by non-reactive rf-magnetron sputtering through a stencil mask on ultra-thin (10 nm) SiO₂ layers containing a single plane of silicon nanocrystals (NCs), synthetized by ultra-low energy ion implantation followed by thermal annealing. The localized ZnO-deposited areas are reproducing the exact stencil mask patterns. A resistivity of around 5 × 10^− 3 Ω cm is measured on ZnO layer. The as-deposited ZnO material is 97% transparent above the wavelength at 400 nm. ZnO nanostructures can thus be used as transparent electrodes for Si NCs embedded in the gate-oxide of MOS devices.