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Bioactive materials, able to induce hydroxyapatite precipitation in contact with body fluids, are of great interest for their bone bonding capacity.. The aim of this paper is to compare bioactive materials with different surface features to verify the mechanisms of action and the relationship with kinetics and type of precipitated hydroxyapatite over time. Four different surface treatments for Ti/Ti6Al4V alloy and a bioactive glass were selected and a different mechanism of bioactivity is supposed for each of them. Apart from the conventional techniques (FESEM, XPS and EDX), less common characterizations (zeta potential measurements on solid surfaces and FTIR chemical imaging) were applied. The results suggest that the OH groups on the surface have several effects: the total number of the OH groups mainly affects hydrophilicity of surfaces, while the isoelectric points, surface charge and ions attraction mainly depend on OH acidic/basic strength. Kinetics of hydroxyapatite precipitation is faster when it involves a mechanism of ion exchange while it is slower when it is due to electrostatic effects. The electrostatic effect cooperates with ion exchange and it speeds up kinetics of hydroxyapatite precipitation. Different bioactive surfaces are able to differently induce precipitation of type A and B of hydroxyapatite, as well as different degrees of crystallinity and carbonation. The bone is made of a ceramic phase (a specific type of hydroxyapatite), a network of collagen fibers and the biological tissue. A strong bond of an orthopedic or dental implant with the bone is achieved by bioactive materials where precipitation and growth of hydroxyapatite occurs on the implant surface starting from the ions in the physiological fluids. Several bioactive materials are already known and used, but their mechanism of action is not completely known and the type of precipitated hydroxyapatite not fully investigated. In this work, bioactive titanium and bioglass surfaces are compared through conventional and innovative methodologies. Different mechanisms of bioactivity are identified, with different kinetics and the materials are able to induce precipitation of different types of hydroxyapatite, with different degree of crystallinity and carbonation. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Even if Ti6Al4V has great biocompatibility, it cannot be used for several components of joint implants because of low wear and fretting resistance. This research is focused on improving the bio-tribological characteristics of Ti6Al4V alloy through a surface boriding process. The borided coating was characterized by microstructural and chemical analyses, hardness and adhesion tests. Adsorption of albumin was verified by surface zeta potential vs pH for characterizing interaction with physiological natural lubricants. A heat treatment at temperature near or above the beta transus allows to obtain a performant coating (thickness, hardness, adhesion) even if a change in microstructure of the substrate occurs. [ABSTRACT FROM AUTHOR]

Bacterial contamination is a critical problem in different fields (ranging from everyday life to space missions, and from medicine to biosensing). Specifically, in the case of medical implants, foreign materials are preferential sites for bacterial adhesion and microbial contamination, which can lead to the development of prosthetic infections. These problems can in turn lead to the necessity of a prolonged antibiotic therapy (which can last for years) and eventually to the removal of the device, with a consequent significant increase in the hospitalization times and costs, together with a stressful, painful and critical situation for the patient. Commercially pure titanium and its alloys are the most commonly used materials for permanent implants in contact with bone, and the prevention of infections on their surface is therefore a crucial challenge for orthopaedic and dental surgeons. The problem of the bacterial contamination of medical implants is briefly described in the first part of the present review. Then the most important inorganic antibacterial agents (Ag, Cu and Zn) are described, and this is followed by a review of the reported attempts of their introduction onto the surface of Ti-based substrates. [ABSTRACT FROM AUTHOR]

Space debris removal is a challenging problem for a clean and safe space environment. The present paper focuses on a novel concept of capture mechanism in the framework of technologies, strategies and concepts known as “tentacles with belts” method. Within this framework two different strategies (based on inorganic or organic materials) have been developed in order to improve the capture efficiency of the belts. The mechanical, tribological and ageing characterization of modified belt fabrics for space application is reported and discussed. [ABSTRACT FROM AUTHOR]

The aim of the present research is to obtain a multiscale topography (micro- and nano-texture) and a high hydroxylation degree on the surface of a dental implant, in order to get advantages for bone integration. Moreover, a specific protocol for verifying the mechanical resistance to friction during implantation of a modified implant surface was developed. An innovative and patented chemical surface treatment was successfully integrated with a traditional dual acid etching process for dental implants. The result is a multiscale surface topography (a nano-texture overlapped on a micro-porosity), together with a significant increase in the surface hydroxyl groups. The treatment is time and cost effective and it allows getting peculiar surface properties. The treated Ti implants are bioactive (they induce hydroxyapatite precipitation during soaking in simulated body fluid) and they show increased wettability and protein absorption ability, compared to the traditional dual-etched implants. Modified implants do not require particular storage conditions and can be sterilized by conventional techniques. An innovative protocol for the evaluation of the surface resistance to implantation friction was developed and it allowed verifying that both traditional dual-etched and innovative Ti surfaces are able to sustain implantation friction without surface damages. Innovative surfaces with multiscale topography (micro- and nano-texture), high hydroxylation degree and protein adsorption, bioactive and hydrophilic behavior, and high resistance to friction during implantation were developed. An effective method for comparing the resistance to friction of the surfaces of dental implants is proposed. [ABSTRACT FROM AUTHOR]

Bioglass® type 45S5 is the most widespread bioactive glass studied for its inorganic bioactivity and ability to affect cell behaviour. In this research work sintered Bioglass® substrates were functionalized with a biological molecule (the enzyme alkaline phosphatase — ALP) in order to couple bioactive glass typical inorganic properties with biological signals. For the first time ALP grafting has been performed on the standard Bioglass® composition, which is the most widely bioactive glass studied and currently commercialized in various forms. ALP was grafted to sintered Bioglass® glass–ceramic pellets both via silanization and via direct bonding to hydroxyl groups exposed on the surface. The presence of the biomolecule was investigated by means of XPS and its activity by enzymatic activity test. In vitro bioactivity of sintered Bioglass® at different steps of the functionalization process was investigated by soaking samples in simulated body fluid (SBF) for various experimental times. The possibility to graft ALP in an active state on sintered Bioglass® samples both via direct grafting and silanization routes has been demonstrated in the present research. ALP enhances and fastens in vitro bioactivity of the glass–ceramic. Surface functionalization of Bioglass® pellets is of interest as model for sintered Bioglass® derived scaffolds to be used in bone engineering. [ABSTRACT FROM AUTHOR]

Abstract: Management of water resources in basins under Mediterranean climate is based on t e knowledge of the complex interaction among rainfall, evapotranspira ion, streamflow discharge, and changes in water storage. Understanding the spatial and temporal evolution of such relations is a key issue for obtaining reliable applications of hydrologica models. In this study we identified the water dynamics involved in the catchment-scale water balance within a sub- humid area in Southern Italy. To meet this objective, precipitation and evapotranspirati n were retrieved through data recorded by a weather station whereas water discharge was monitored at the water reservoir delimited by an earth dam in the outlet of the Alento River 102.5 km2 catchment. The landuse is dominated by pasture, orchard and grassland and the main terrain attributes have been calculated from a 5 m DEM. Six hillslope transects have been delineated along hillslopes in order to cap ure soil variability. Surface soil water content has been monitored with a portable TDR device along the aforementioned transects with a spatial interval of 50 m in 10 field campaigns, from October 2004 to January 2005. Mediterranean climate is characterized by dry summers with strong water deficit and wet winters with replenishment of the water reservoir. In the dry season, soil water content has high tempora instability and is mainly influenced by the aspect and tangential curvature. On the other hand during the wet season near saturation conditions of soil surface are able to diagnose rapid streamflow response since rainfall events generate runoff and subsurface later flow. Soil water content is more stable and shows a signifi ant correlation with the slope and the wetness index. [Copyright &y& Elsevier]

Abstract: Numerical simulations have been conducted for large scale hydrogen detonation by solving Euler equations with a single step reaction for the chemistry. A total variation diminishing numerical scheme is used for shock capturing. Predictions were firstly conducted with a small domain to ensure that the reaction scheme has been properly tuned to capture the correct detonation pressure and velocity. On this basis, simulations were conducted for the detonation tests carried out at Kurchatov Institute in Russia . Comparison is made between the predictions and measurements. Further simulations were then conducted for a hypothetical hydrogen-air cloud in the open to assess the impulse as well as overpressure distributions. [Copyright &y& Elsevier]

[Display omitted] • Chemically treated Ti6Al4V can be surface functionalized with polyphenols from red grape pomace. • The grafting link is between deprotonated OH surface groups and Ca2+ ions forming a complex with the polyphenols. • The grafted polyphenols have redox chemical and radical scavenging ability on the metallic surface. • The polyphenols are released in aqueous media. • The functionalized surfaces can be sterilized by gamma irradiation. The focus of the paper is on effectiveness of a functionalization process with natural polyphenols on a chemically treated and bioactive Ti6Al4V alloy, on the grafting mechanism, and the redox/scavenging activity of the grafted biomolecules. Polyphenols (phenolic acids, flavonoids, and condensed tannins) are extracted from organic red grape pomace. The functionalization process is performed at pH = 7.4 with the addition of calcium ions, which act as a bridge between the substrate and polyphenols. The presence, amount (semi-quantitative), distribution, release, and type of bonding to the surface of the grafted polyphenols have been assessed. The functionalized samples have a homogeneous distribution of polyphenols as a continuous layer and micro-sized agglomerates. The grafted polyphenols maintain redox chemical and radical scavenging ability. A fraction of polyphenols is released into water in one day, while a firmly grafted layer remains on the surface even after four weeks. A complete release can occur in case of an environment with pH of 4–5 (e.g. inflammation). The functionalized surfaces can be sterilized by gamma irradiation without significant damage of the grafted polyphenols. [ABSTRACT FROM AUTHOR]

Within scenarios of water scarcity, the irrigation efficiency plays an increasingly strategic role. In this paper, a method that uses an advance-infiltration model based on four field measurements and the soil particle size distribution is proposed to estimate border-irrigation efficiencies. This method was applied to fifteen irrigation events and the application, storage and distribution efficiencies were estimated. The advance-infiltration model was validated against soil moisture measurements. The field-scale saturated hydraulic conductivity was estimated by model fitting to the measured depth of water infiltration. The sensitivity of the modelled irrigation efficiency to the operational surface irrigation parameters was evaluated by simulating seven irrigation scenarios based on field-collected data. The infiltration profiles obtained by the proposed method were in agreement with the soil moisture measurements. The maximum difference between simulated and measured infiltration depth was 0.018 m. The field-scale saturated hydraulic conductivity values were in agreement with the infiltrometer tests results. The analysis of both simulated scenarios and monitored irrigation events highlighted the need for farmers to reduce the flow rates and increase the duration of irrigation events, in order to improve the irrigation efficiencies. [ABSTRACT FROM AUTHOR]

Abstract: Micro-basins are slope management structures built out of earth and stones on hillslopes around cultivated trees (e.g., olive trees) for the harvesting of rainfall and runoff water, and for the rehabilitation of land degraded by water erosion. In this study, the results of an experimental survey for the comparison of soil water content for both inside and outside the micro-basins are analyzed. Measurements are taken after some rainfall events from January to December 2003 in a hilly region of Central Tunisia. The time domain reflectometry technique is used to measure soil moisture in 15 sets of soil profiles (inside and outside) at three different depths. Four different soils are evaluated, i.e., Cambisols, Kastanozems, Arenosols, and Calcisols. The data analysis shows a significant improvement on the water stock obtained by this type of management. The differences in water storage with respect to soil type, depths, and tillage are evident, but strongly connected to farm management. For optimal management conditions an important increase of average water stock is observed; however, for bad or no farm management the amelioration is zero or is even deteriorating the state of vegetation. [Copyright &y& Elsevier]

The recently developed engineered nucleases, such as zinc-finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease (Cas) 9, provide new opportunities for gene editing in a straightforward manner. However, few reports are available regarding CRISPR application and efficiency in cattle. Here, the CRISPR/Cas9 system was used with the aim of inducing knockout and knock-in alleles of the bovine PRNP gene, responsible for mad cow disease, both in bovine fetal fibroblasts and in IVF embryos. Five single-guide RNAs were designed to target 875 bp of PRNP exon 3, and all five were codelivered with Cas9. The feasibility of inducing homologous recombination (HR) was evaluated with a reporter vector carrying EGFP flanked by 1 kbp PRNP regions (pHR egfp ). For somatic cells, plasmids coding for Cas9 and for each of the five single-guide RNAs (pCMVCas9 and pSPgRNAs) were transfected under two different conditions (1X and 2X). For IVF zygotes, cytoplasmic injection was conducted with either plasmids or mRNA. For plasmid injection groups, 1 pg pCMVCas9 + 0.1 pg of each pSPgRNA (DNA2X) was used per zygote. In the case of RNA, two amounts (RNA1X and RNA2X) were compared. To assess the occurrence of HR, a group additionally cotransfected or coinjected with pHR egfp plasmid was included. Somatic cell lysates were analyzed by polymerase chain reaction and surveyor assay. In the case of embryos, the in vitro development and the genotype of blastocysts were evaluated by polymerase chain reaction and sequencing. In somatic cells, 2X transfection resulted in indels and large deletions of the targeted PRNP region. Regarding embryo injection, higher blastocyst rates were obtained for RNA injected groups (46/103 [44.6%] and 55/116 [47.4%] for RNA1X and RNA2X) than for the DNA2X group (26/140 [18.6%], P < 0.05). In 46% (26/56) of the total sequenced blastocysts, specific gene editing was detected. The total number of genetic modifications (29) was higher than the total number of gene-edited embryos, as three blastocysts from the group RNA2X reported more than one type of modification. The modifications included indels (10/56; 17.9%) and large deletions (19/56; 33.9%). Moreover, it was possible to detect HR in 1/8 (12.5%) embryos treated with RNA2X. These results report that the CRISPR/Cas9 system can be applied for site-specific edition of the bovine genome, which could have a great impact on the development of large animals resistant to important zoonotic diseases. [ABSTRACT FROM AUTHOR]