Design and proof of concept for multi degree of freedom hydrostatically coupled dielectric elastomer actuators with roto-translational kinematics for object handling

In this article we present an upgraded design of the existing push-pull hydrostatically coupled dielectric elastomer actuator (HC-DEA) for use in the field of soft manipulators. The new design has segmented electrodes, which stand as four independent elements on the active membrane of the actuator. When properly operated, the actuator can generate both out of plane and in-plane motions resulting in a multi-degrees of freedom soft actuator able to exert both normal pushes (like a traditional HC-DEA) and tangential thrusts. This novel design makes the actuator suitable for delicate flat object transportation. In order to use the actuator in soft systems, we experimentally characterized its electromechanical transduction and modeled its contact mechanics. Finally, we show that the proposed actuator can be employed as a modular unit to develop active surfaces for flat object roto-translation. © 2018 IOP Publishing Ltd

Physicochemical Characterization of Pectin-Gelatin Biomaterial Formulations for 3D Bioprinting.

AbstractDeveloping biomaterial formulations with specific biochemical characteristics and physical properties suitable for bioprinting of 3D scaffolds is a pivotal challenge in tissue engineering. Therefore, the design of novel bioprintable formulations is a continuously evolving research field. In this work, the authors aim at expanding the library of biomaterial inks by blending two natural biopolymers: pectin and gelatin. Cytocompatible formulations are obtained by combining pectin and gelatin at different ratios and using (3‐glycidyloxypropyl)trimethoxysilane (GPTMS) as single crosslinking agent. It is shown that the developed formulations are all suitable for extrusion‐based 3D bioprinting. Self‐supporting scaffolds with a designed macroporosity and micropores in the bioprinted struts are successfully obtained by combining extrusion‐based bioprinting and freeze‐drying. The presence of gelatin in these formulations allows for the modulation of porosity, of water uptake and of scaffold stiffness in respect to pure pectin scaffolds. Results demonstrate that these new biomaterial formulations, processed with this specific approach, are promising candidates for the fabrication of tissue‐like scaffolds for tissue regeneration

One-pot process: Microwave-assisted keratin extraction and direct electrospinning to obtain keratin-based bioplastic

Poultry feathers are among the most abundant and polluting keratin-rich waste bio-masses. In this work, we developed a one-pot microwave-assisted process for eco-friendly keratin extraction from poultry feathers followed by a direct electrospinning (ES) of the raw extract, without further purification, to obtain keratin-based bioplastics. This microwave-assisted keratin extraction (MAE) was conducted in acetic acid 70% v/v. The effects of extraction time, solvent/feathers ratio, and heating mode (MAE vs conventional heating) on the extraction yield were investigated. The highest keratin yield (26 ± 1% w/w with respect to initial feathers) was obtained after 5 h of MAE. Waste-derived keratin were blended with gelatin to fabricate keratin-based biodegradable and bio-compatible bioplastics via ES, using 3-(Glycidyloxypropyl)trimethoxysilane (GPTMS) as a cross-linking agent. A full characterization of their thermal, mechanical, and barrier properties was performed by differential scanning calorimetry, thermogravimetric analysis, uniaxial tensile tests, and water permeability measurements. Their morphology and protein structure were investigated using scanning electron microscopy and attenuated total reflection-infrared spectroscopy. All these characterizations highlighted that the properties of the keratin-based bioplastics can be modulated by changing keratin and GPTMS concentrations. These bioplastics could be applied in areas such as bio-packaging and filtration/purification membranes

Extended genetic diversity of bovine viral diarrhea virus and frequency of genotypes and subtypes in cattle in Italy between 1995 and 2013

Genetic typing of bovine viral diarrhea virus (BVDV) has distinguished BVDV-1 and BVDV-2 species and an emerging putative third species (HoBi-like virus), recently detected in southern Italy, signaling the occurrence of natural infection in Europe. Recognizing the need to update the data on BVDV genetic variability in Italy for mounting local and European alerts, a wide collection of 5 \u2032 UTR sequences (n = 371) was selected to identify the frequency of genotypes and subtypes at the herd level. BVDV-1 had the highest frequency, followed by sporadic BVDV-2. No novel HoBi-like viruses were identified. Four distribution patterns of BVDV-1 subtypes were observed: highly prevalent subtypes with a wide temporal-spatial distribution (1b and 1e), low prevalent subtypes with a widespread geographic distribution (1a, 1d, 1g, 1h, and 1k) or a restricted geographic distribution (1f), and sporadic subtypes detected only in single herds (1c, 1j, and 1l). BVDV-1c, k, and l are reported for the first time in Italy. A unique genetic variant was detected in the majority of herds, but cocirculation of genetic variants was also observed. Northern Italy ranked first for BVDV introduction, prevalence, and dispersion. Nevertheless, the presence of sporadic variants in other restricted areas suggests the risk of different routes of BVDV introduction

Use of pJANUS™-02-001 as a calibrator plasmid for Roundup Ready soybean event GTS-40-3-2 detection: an interlaboratory trial assessment

Owing to the labelling requirements of food and feed products containing materials derived from genetically modified organisms, quantitative detection methods have to be developed for this purpose, including the necessary certified reference materials and calibrator standards. To date, for most genetically modified organisms authorized in the European Union, certified reference materials derived from seed powders are being developed. Here, an assessment has been made on the feasibility of using plasmid DNA as an alternative calibrator for the quantitative detection of genetically modified organisms. For this, a dual-target plasmid, designated as pJANUS™-02-001, comprising part of a junction region of genetically modified soybean event GTS-40-3-2 and the endogenous soybean-specific lectin gene was constructed. The dynamic range, efficiency and limit of detection for the soybean event GTS-40-3-2 real-time quantitative polymerase chain reaction (Q-PCR) system described by Terry et al. (J AOAC Int 85(4):938–944, 2002) were shown to be similar for in house produced homozygous genomic DNA from leaf tissue of soybean event GTS-40-3-2 and for plasmid pJANUS™-02-001 DNA backgrounds. The performance of this real-time Q-PCR system using both types of DNA templates as calibrator standards in quantitative DNA analysis was further assessed in an interlaboratory trial. Statistical analysis and fuzzy-logic-based interpretation were performed on critical method parameters (as defined by the European Network of GMO Laboratories and the Community Reference Laboratory for GM Food and Feed guidelines) and demonstrated that the plasmid pJANUS™-02-001 DNA represents a valuable alternative to genomic DNA as a calibrator for the quantification of soybean event GTS-40-3-2 in food and feed products

Loss of Octarepeats in Two Processed Prion Pseudogenes in the Red Squirrel, Sciurus vulgaris

The N-terminal region of the mammalian prion protein (PrP) contains an ‘octapeptide’ repeat which is involved in copper binding. This eight- or nine-residue peptide is repeated four to seven times, depending on the species, and polymorphisms in repeat number do occur. Alleles with three repeats are very rare in humans and goats, and deduced PrP sequences with two repeats have only been reported in two lemur species and in the red squirrel, Sciurus vulgaris. We here describe that the red squirrel two-repeat PrP sequence actually represents a retroposed pseudogene, and that an additional and older processed pseudogene with three repeats also occurs in this species as well as in ground squirrels. We argue that repeat numbers may tend to contract rather than expand in prion retropseudogenes, and that functional prion genes with two repeats may not be viable

Fabrication and characterization of gelatin/carbon black–based scaffolds for neural tissue engineering applications

Neural tissue engineering has recently emerged as an alternative strategy to repair nerve damage and promote nerve regeneration. It involves the fabrication of scaffolds with properties mimicking those of the natural extracellular matrix for guiding a three-dimensional (3D) neural regeneration. These engineered constructs, in addition to mechanical support, should be also capable of providing proper chemical and electrical stimuli for adhesion, migration, and proliferation of the neural cells. In this study, we developed conductive composite hydrogel films based on gelatin and carbon black (CB) as scaffolds for neural tissue engineering applications. The presented hydrogel constructs were fabricated in the form of films using the solvent casting method after dispersing several concentrations of CB in a 5 % (w/v) gelatin solution along with (3-glycidoxypropyl) trimethoxysilane (GPTMS) as the crosslinking agent at a concentration of 1.84 % (v/v). The CB concentrations of 0.3 %, 0.5 %, 0.7 %, and 0.9 % (w/w) with respect to the gelatin amount were chosen. The morphological, compositional, swelling, dissolution, electrical, mechanical, and wettability properties together were characterized as function of CB content and compared with those of pure gelatin-based hydrogel. Results demonstrated that the incorporation of different quantities of CB relatively reduced the water uptake capability of the films and increased the stability in water of the gelatin matrix. Findings from the mechanical tests revealed that composite hydrogels have a lower elastic modulus with respect to the pure gelatin matrix. Moreover, it was found that the incorporation of incremental CB concentrations kept the wettability surface property unchanged while the electrical characterization of the proposed structures showed a reduction of the electrical impedance. Overall, the study suggests that the composite structures could be used as a potential candidate for fabrication of scaffolds for neural regeneration with tunable electrical and mechanical properties by varying the CB concentration in a finite range

Nitrate leaching under maize cropping systems in Po Valley (Italy)

Intensive crop production in Po Valley (Northern Italy) is associated to high risk of nitrate leaching. A multi-year monitoring of soil solution nitrogen was conducted at 6 sites under the ordinary farm management of maize crop (Zea mays L.) in order to assess NO 3-N leaching. The amount of N fertilizer (organic+mineral) varied from 209 to 801kgNha -1year -1. Maize biomass ranged from 15 to 32tha -1 and N removal from 150 to 400kgha -1. Soil water solution was sampled at five depths along the soil profile (from 0.3 to 1.5m) at time intervals of 7-30 days using suction cups. Soil water content (SWC) was measured daily by TDR at the same depths of suction cups. Soil water NO 3-N concentrations varied from 0 to 110mgL -1, with the highest concentrations measured after fertilizer application. Once validated on measured SWC data, SWAP model was applied to estimate the drainage flux. Annual leaching was calculated by multiplying drainage flux by soil water NO 3-N concentration. N Leaching ranged from 14 to 321kgha -1year -1, according to fertilization, crop N removal, rainfall, irrigation management, and it was mainly affected by N surplus