Waterproof,Breathable, and Antibacterial Self‐Powered e‐Textiles Based on Omniphobic Triboelectric Nanogenerators

Multifunctional electronic textiles (e‐textiles) incorporating miniaturized electronic devices will pave the way toward a new generation of wearable devices and human–machine interfaces. Unfortunately, the development of e‐textiles is subject to critical challenges, such as battery dependence, breathability, satisfactory washability, and compatibility with mass production techniques. This work describes a simple and cost‐effective method to transform conventional garments and textiles into waterproof, breathable, and antibacterial e‐textiles for self‐powered human–machine interfacing. Combining embroidery with the spray‐based deposition of fluoroalkylated organosilanes and highly networked nanoflakes, omniphobic triboelectric nanogenerators (R^F‐TENGs) can be incorporated into any fiber‐based textile to power wearable devices using energy harvested from human motion. R^F‐TENGs are thin, flexible, breathable (air permeability 90.5 mm s^?1), inexpensive to fabricate (<0.04$ cm^?2), and capable of producing a high power density (600 µW cm^?2). E‐textiles based on R^F‐TENGs repel water, stains, and bacterial growth, and show excellent stability under mechanical deformations and remarkable washing durability under standard machine‐washing tests. Moreover, e‐textiles based on R^F‐TENGs are compatible with large‐scale production processes and exhibit high sensitivity to touch, enabling the cost‐effective manufacturing of wearable human–machine interfaces.     

Development and characterisation of 3D printing finishing process applying recycled plastic waste

In recent years, additive manufacturing technologies have been playing an important role in the global economy. Consequently, low-cost 3D printers rose in the domestic environment, accelerating the development of startup companies and new market segments. Nevertheless, with regard to 3D printing based on fused filament fabrication, several challenges still need to be overcome, such as those related to surface finishing and mechanical strength. Moreover, 3D printing in the domestic environment also generates untreated plastic waste, which can cause environmental problems. For these reasons, the main goal of this work is to introduce and characterise 3D printing surface finishing post-processing using recycled plastic waste. As the main results of this work, the proposed recycling process was confirmed to improve object properties. Whereas surface roughness was reduced from 27 to 3?µm, while mechanical strength was increased in 20 times. The application of recycled material for chemical welding was also seen to be feasible.     

Synthesis and characterization of poly(N-vinylcaprolactam)-based spray-dried microparticles exhibiting temperature and pH-sensitive properties for controlled release of ketoprofen

Poly(N-vinylcaprolactam) (PNVCL) and poly(N-vinylcaprolactam-co-acrylic acid) (poly(NVCL-co-AA)) were synthesized by solution-free radical polymerization and displayed thermo-responsive behavior, with lower critical solution temperatures (LCSTs) of 35?°C and 39?°C, respectively. The incorporation of AA unities made the poly(NVCL-co-AA) sensitive to both pH and temperature. They were exploited in this work in preparing microparticles loaded with ketoprofen via spray-drying to modulate the drug release rate by changing pH or temperature. The interaction between polymer and drug was studied using X-ray diffractometry, Raman spectrometry and scanning electron microscopy (SEM). The biocompatibility of pure polymers, free ketoprofen as well as the spray-dried particles was demonstrated in vitro by low cytotoxicity and a lack of nitric oxide production in macrophages at concentrations as high as 100?µg/ml. The release profile of ketoprofen was evaluated by in vitro assays at different temperatures and pH values. Drug diffusion out of PNVCL’s hydrated polymer network is increased at temperatures below the LCST. However, when poly(NVCL-co-AA) was used as the matrix, the release of ketoprofen was primarily controlled by the pH of the medium. These results indicated that PNVCL and the novel poly(NVCL-co-AA) could be promising candidates for pH and temperature-responsive drug delivery systems.     

Poly(lactic acid)/poly(vinyl pyrrolidone) membranes produced by solution blow spinning: Structure,thermal, spectroscopic,and microbial barrier properties

Submicrometric and nanometric poly(lactic acid)/poly(vinyl pyrrolidone) (PLA/PVP) fibrous membranes containing 0, 5, 10, 15, and 20 wt % PVP, with or without 20 wt % Copaiba oil (Copaifera sp.), were produced by solution blow spinning (SBS), using polymer injection rate of 120 μL min^?1, gas pressure of 2.4 kPa, working distance of 20 cm, and collector rotation of 200 rpm. The morphological, thermal, and spectroscopic properties of these membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry (TG), and Fourier transform infrared spectroscopy (FTIR). A method for the evaluation of membrane microbial barrier properties based on resazurin colorimetric method was proposed. Results showed that the addition of both PVP and Copaiba oil produced thicker fibers; otherwise, there was no effect on morphology. Thermal analyses (TG and DSC) indicated the immiscible nature of polymer blends produced, also confirmed by the spectroscopic studies. Antimicrobial barrier properties were related to the antimicrobial effect of Copaiba oil, combined with it hydrophobic nature. The hydrophilic nature of PVP favored degradation of fiber mats, impairing barrier property when higher concentrations of PVP were added. Results indicate that produced spun mats can potentially be used in applications such as wound dressing. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44802.     

Analysing NBTI Impact on SRAMs with Resistive Defects

Density’s increase in Static Random Access Memory (SRAM) has become an important concern for testing, since new types of defects, that may occur during the manufacturing process, are introduced. On the one hand, new manufacturing defects may lead to dynamic faults, which are considered one of the most important causes of test escape in deep-submicron technologies. On the other hand, the SRAM’s robustness is considered crucial, since it may affect the entire SoC. One of the most important phenomena to degrade SRAM reliability is Negative-Bias Temperature Instability (NBTI) causing the memory cells’ aging. In this context, the paper proposes to analyse the impact of NBTI on SRAM cells with resistive defects that eventually escape manufacturing test and, with aging, may generate faults over time. Finally, SPICE simulations adopting a commercial 65 nm CMOS technology library have been performed in order to estimate NBTI’s precise impact over time.     

Flow injection amperometric detection of 2'-deoxyguanosine at a ruthenium oxide hexacyanoferrate modified electrode

A ruthenium oxide hexacyanoferrate (RuOHCF) modified electrode was developed. Hydrodynamic voltammetry was employed to demonstrate the remarkable electrocatalytic activity toward the oxidation of 2'-deoxyguanosine. The RuOHCF modified electrode was used as amperometric detector for 2'-deoxyguanosine determination in a FIA apparatus. The influence of various experimental conditions was explored for optimum analytical performance, and at these experimental conditions, the method exhibited a linear response range to 2'-deoxyguanosine extending from 3.8 to 252 micromol L(-1) with detection limit of 94 nmol L(-1). Applications in DNA samples were examined, and the results for determination of 2'-deoxyguanosine were in good agreement with those obtained by HPLC analysis. Studies on the kinetics of the in vitro consumption of 2'-deoxyguanosine by acetaldehyde were also performed.     

A biodegradable composite material based on polyhydroxybutyrate (PHB) and carnauba fibers

In this investigation, carnauba fibers obtained from the leaves of the carnauba palm tree were chemically modified and their potential for the development of a biodegradable composite was evaluated. Fiber treatments to improve interfacial bonding were carried out by alkali, peroxide, potassium permanganate and acetylation. Biodegradable composites were prepared using carnauba fibers and polyhydroxybutyrate (PHB) as matrix. Mechanical properties of the composites prepared with 10 wt.% of short carnauba fibers were investigated and related to fiber treatment. According to the results, the tensile strength of the composites made from peroxide treated fibers was superior to those using untreated fibers or any other fiber treatment. SEM observations on the fracture surface of the composites suggest improved fiber–matrix adhesion after peroxide treatment. This surface modification of the fibers was found to contribute to the enhancement of the mechanical properties of the composites, even though the tensile strength of the fibers was slightly reduced. Dynamic mechanical thermal analyses suggested improvement in storage modulus of the composites reinforced with carnauba fibers at higher temperatures as compared to the neat polymer.     

New insights on the metabolism of ricinoleic acid in ruminants

Dairy goats were fed a total mixed ration with or without the inclusion of castor oil [40 g/kg of dry matter (DM)] to study the metabolism of ricinoleic acid (12-OH,cis-9–18:1). Ten goats, at 39.7 ± 4.0 d in milk, were individually penned and allocated at random to the 2 experimental diets. Goats were manually milked twice a day. Milk fatty acids (FA) were analyzed as methyl esters and hydroxyl groups were derivatized in trimethylsilyl ethers. Apart from ricinoleic acid, 6 FA were only detected in the milk of the castor oil group. Ricinoleic acid composed 0.3% of total FA in milk of the castor oil group, whereas the hydroxy-FA (8-OH-14:0, 10-OH-16:0, and 12-OH-18:0) and oxo-FA (8-oxo-14:0, 10-oxo-16:0, and 12-oxo-18:0) reached 7.5% of total FA in milk. We anticipate that these FA were derived from the metabolism of ricinoleic acid, although it was not clear if they were produced in the rumen or in the tissues. To confirm that, we conducted in vitro batch incubations repeated for 3 consecutive weeks with castor oil (40 g/kg of DM) and strained rumen fluid from 2 fistulated sheep. To examine the products formed over time, incubation tubes were stopped at 0, 6, 12, 24, 48, and 72 h. The results of the in vitro experiment showed that ricinoleic acid was metabolized in the rumen at a slow rate and the main products formed were 12-OH-18:0 and 12-oxo-18:0, by hydrogenation of the cis-9 double bond, followed by oxidation of the hydroxyl group, respectively. Our results suggest that the 12-OH-18:0 and 12-oxo-18:0 escape rumen and are further metabolized through partial β-oxidation in ruminant tissues. We propose that the 10-OH-16:0 and 8-OH-14:0 found in goat milk of the castor oil group are successive products of the β-oxidation of 12-OH-18:0, and the 10-oxo-16:0 and 8-oxo-14:0 are successive products of the 12-oxo-18:0 in tissues. Overall, our results indicate that ricinoleic acid is extensively metabolized in the rumen and tissues, producing mainly oxo- and hydroxy-FA that are further excreted in milk.