Activity of water in aqueous systems; A frequently neglected property

In this critical review, the significance of the term ‘activity’ is examined in the context of the properties of aqueous solutions. The dependence of the activity of water(ℓ) at ambient pressure and 298.15 K on solute molality is examined for aqueous solutions containing neutral solutes, mixtures of neutral solutes and salts. Addition of a solute to water(ℓ) always lowers its thermodynamic activity. For some solutes the stabilisation of water(ℓ) is less than and for others more than in the case where the thermodynamic properties of the aqueous solution are ideal. In one approach this pattern is accounted for in terms of hydrate formation. Alternatively the pattern is analysed in terms of the dependence of practical osmotic coefficients on the composition of the aqueous solution and then in terms of solute–solute interactions. For salt solutions the dependence of the activity of water on salt molalities is compared with that predicted by the Debye–Hückel limiting law. The analysis is extended to consideration of the activities of water in binary aqueous mixtures. The dependence on mole fraction composition of the activity of water in binary aqueous mixtures is examined. Different experimental methods for determining the activity of water in aqueous solutions are critically reviewed. The role of water activity is noted in a biochemical context, with reference to the quality, stability and safety of food and finally with regard to health science.

Enhancing tourism through viticulture enterprises in Douro Region: The Inov@Douro model

This paper describes a business and technological model proposal, known as Inov@Douro, intended to support and to promote competitive and sustained precision agriculture practices in the Portuguese Douro Region. Our approach is based on a distributed cooperative network, tailored to meet the specific needs of viticulture enterprises which also explore tourism as a valuable national and international business source. We present the Inov@Douro model from the knowledge generation point-of-view, intended to support the multidisciplinary concept of a cooperation approach among regional partners. This model aims to represent a new working style for this unique region. As a guideline to attain the implementation of such a model, information technology and infrastructures tools are discussed in order to promote precision agriculture practices while giving valuable and dynamic tourist information to the general public

A new species of Rhamdella Eigenmann & Eigenmann, 1888 (Siluriformes: Heptapteridae) from the coastal basins of southern Brazil

Rhamdella zelimai, new species, is described from the coastal river drainages in northeastern Rio Grande do Sul and southern Santa Catarina States, Brazil. The new species is readily distinguished from its congeners by the hypertrophy of the rictal fold, mainly its lower portion, consisting of a large and fleshy lobe that bends ventrally on itself. The phylogenetic relationships of the new species are assessed and it was recovered as belonging to the clade composed of R. eriarcha (from the laguna dos Patos basin), R. longiuscula (from the rio Uruguai), and R. cainguae (from the lower rio Paraná)

Death Receptor 5 Displayed on Extracellular Vesicles Decreases TRAIL Sensitivity of Colon Cancer Cells

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is considered to be a promising antitumor drug because of its selective proapoptotic properties on tumor cells. However, the clinical application of TRAIL is until now limited because of the resistance of several cancer cells, which can occur at various levels in the TRAIL signaling pathway. The role of decoy receptors that can side-track TRAIL, thereby preventing the formation of an activated death receptor, has been extensively studied. In this study, we have focused on extracellular vesicles (EVs) that are known to play a role in cell-to-cell communication and that can be released by donor cells into the medium transferring their components to recipient cells. TRAIL-induced apoptotic signaling is triggered upon the binding of two death receptors, DR4 and DR5. Here, we found that DR5 but not DR4 is present in the conditioned medium (CM)-derived from various cancer cells. Moreover, we observed that DR5 was exposed on EVs and can act as "decoy receptor" for binding to TRAIL. This results in a strongly reduced number of apoptotic cells upon treatment with DR5-specific TRAIL variant DHER in CM. This reduction happened with EVs containing either the long or short isoform of DR5. Taken together, we demonstrated that colon rectal tumor cells can secrete DR5-coated EVs, and this can cause TRAIL resistance. This is to our knowledge a novel finding and provides new insights into understanding TRAIL sensitivity

Creating new functional biomaterials: construction and production of Bone Morphogenetic 2-ELP hybrid proteins

Bone morphogenetic protein 2 (BMP-2) is a potent osteoinductive cytokine from the TGF-β superfamily that triggers the development of stem cells into osteoblasts. Its therapeutic interest has led to the development of various production systems for recombinant variables of BMP-2. Production has been achieved in expression systems ranging from animal cells to bacteria, but is always associated with three major drawbacks: low production rates (in animal cells), low activity (bacterial cells) and low solubility due to aggregation in inclusion bodies (bacterial cells) [1]. In this study we have developed a strategy to overcome the low production levels as well as the insolubility of BMP-2 in E. coli by fusing it with an elastin like polymer (ELP). This recombinant ELP, based on repetitions of the main monomer VPAVG, displays no measurable cytotoxicity [2] and exhibits thermoresponsive properties as well as hysteresis behaviour [3]. By exploring this thermal responsiveness we are able to purify the fusion protein using a simple and low cost method and thus avoid expensive chromatographic techniques. The mature human-BMP2 domain was cloned in frame to the N-terminus of the (VPAVG)n (n = 60 or 220) polymers. The production of the genetic constructs was achieved in E. coli BL21 (DE3) with Lysogeny Broth (LB) supplemented with lactose for auto-induction. Purification of the hybrid BMP2:(VPAVG)n polymers was accomplished by exploring the thermal responsiveness of the ELP tail. Physical and chemical characterization as well as bioactivity studies of both constructs are currently in progress. 1. Bessa P. C., Casal M., Reis R. L. (2008) “Bone morphogenetic proteins in tissue engineering: the road from laboratory to the clinic, part I (Basic concepts)”, Journal of tissue engineering and regenerative medicine 2, 1-13; 2. Bessa, P., Machado, R., Nürnberger , S., Dopler, D., Banerjee, A., Cunha, A. M., Rodríguez-Cabello, C., Redl, H., van Griensven, M., Reis, R.L., Casal, M. 2010. Thermoresponsive self-assembled elastin-based nanoparticles for delivery of BMPs. Journal of Controlled Release 142: 312–318. 3. Machado R., Ribeiro A., Padrão J., Silva D., Nobre A., Teixeira J., Arias F., Cunha A., Rodroguez-Cabello J., Casal M. (2009) “Exploiting the natural ocurring elastin: construction, production and characterization of a recombinant thermoplastic protein-based polymer”, Journal of Nano Research, 6, 133-145

Silk bilayer scaffolds can induce fast integration with subchondral bone and support cartilage repair

Publicado em : J Tissue Eng Regen Med 2014; 8 (Suppl. 1)Introduction: Osteochondral defect (OCD) regeneration presents major challenges in orthopedics. Since healing of cartilage and bone should be simultaneously considered, ideal scaffolds should be those that can mimic both tissues properties. In this study, bilayered silk and silk-nano calcium phosphate (Silk/Silk-NanoCaP) scaffolds with tailored mechanical properties were developed for OCD tissue engineering application. Materials and methods: Aqueous silk solution (16%) was prepared.1 Nano calcium phosphate particles (16%) were synthesized in the silk solution (Silk-NanoCaP).2 The bony layer was prepared by addition of NaCl particles (500–1000 lm) into the Silk-NanoCaP suspension. After drying for 2 days and salt-leaching overnight, silk solution was added on top of the bony layer using the same procedure to produce the chondral layer. The !nal scaffolds were evaluated through in vitro culture of rabbit bone marrow stromal cells (RBMSCs) for 2 weeks, and in vivo implantation in a rabbit knee OCD for 4 weeks. Results: The RBMSCs cultured in the scaffolds presented increasing viability from day 1 to day 7 by MTS assay. Good adhesion and migration of the RBMSCs in the scaffolds were achieved, as observed under the scanning electron microscope. Cell proliferation was observed from day 7 to day 14 as determined by DNA quanti!cation. The bony layer induced higher alkaline phosphatase level as compared to the chondral layer, in osteogenic condition. Histological analysis (H&E) showed that the bilayered scaffolds integrated well with the host tissue, after 4 weeks of implantation in a critical size OC defect (Fig. 1). Abundant new bone formation was detected in the Silk-NanoCaP layer. Cartilage regeneration occurred in the silk layer. Discussion and conclusions: The bilayered scaffolds favored the attachment, proliferation, and differentiation of RBMSCs. The bony layer of the bilayered scaffolds possessed osteoconductive properties. The bilayered scaffolds were biocompatible in vitro and in vivo. These scaffolds also induced both subchondral bone regeneration and supported cartilage regeneration, thus showing great promise in OCD regeneration. Acknowledgments: The authors thank FCT projects Tissue2Tissue and OsteoCart, and the FP7 Programme POLARIS. Yan LP was awarded a FCT PhD scholarship. Investigador FCT program (IF/00423/2012) and (IF/00411/2013) are also greatly acknowledged. Disclosure: The authors declare that there is no con"ict of interest

New endoscopic procedure for bladder wall closure: results from the porcine model

Upper urinary tract urothelial carcinomas are usually managed by radical nephroureterectomy (RNU), often followed by intravesical chemotherapy to minimize recurrence. Open surgery is the gold standard procedure for RNU, but it associates with high morbidity, and it has been increasingly replaced by minimally invasive strategies, such as laparoscopy and endoscopy. Although effective, endoscopic ureteral excision leaves the bladder unsutured, increasing the risk of tumor spillage, and precluding the immediate administration of intravesical chemotherapy. Here we describe a new method to close the bladder wall after ureteral excision, using barbed sutures via the endoscopic access. Our results in 8 female pigs demonstrate that this method is effective to close the bladder wall. The procedure was completed in a median time of 24 min, and no adverse events were registered in the follow-up or at the three-week necropsy. This technique improves a previous approach described by our group because the device is more flexible and allows to tie the knots inside the bladder. Barbed sutures have been used in the clinical practice for other types of surgeries, and therefore this method can further be adapted to human patients with no safety concerns. Its use may allow to administer intravesical chemotherapy, which reduces tumor recurrence and improves patient outcomes.The authors acknowledge Ana Goios for support in manuscript writing and technical editing, and for producing original illustrations for Figure 3. Doctoral grant of CUF Jose de Mello Saude

Thiolated chitosan/glycosaminoglycans multilayered films : QCM-D study on the films formation and their biological properties

Layer-by-layer technique is widely used to produce polyelectrolyte multilayered films for material surface functionalization. The technique simplicity coupled with the biological potential of biopolymers, e.g. polysaccharides, make such assemblies a suitable choice for many biomedical applications. In this study the formation of the films comprising of thiolated chitosan and glycosaminoglycans (GAGs) by alternate deposition was assessed in situ using QCM-D. Thiolated chitosan was used under the hypothesis of disulfide formation between its molecules to increase stability and/or stiffness of the films. The effects of the chitosan modification degree and GAGs molecular weight on the film thickness were investigated. All experimental groups showed exponential film growth, while the thickness increased with the chitosan thiolation degree and molecular weight of GAGs. Cellular behavior on the assemblies was found to be tunable by the appropriate selection of the terminate layer. Antimicrobial activity and protein adsorption on the new constructs are also commented

1-(4-Bromo­phen­yl)-2-ethyl­sulfinyl-2-(phenyl­selan­yl)ethanone monohydrate

In the title hydrate, C16H15BrO2SSe·H2O, the sulfinyl O atom lies on the opposite side of the mol­ecule to the Se and carbonyl O atoms. The benzene rings form a dihedral angle of 51.66 (17)° and are splayed with respect to each other. The observed conformation allows the water mol­ecules to bridge sulfinyl O atoms via O—H⋯O hydrogen bonds, generating a linear supra­molecular chain along the b axis; the chain is further stabilized by C—H⋯O contacts. The chains are held in place in the crystal structure by C⋯H⋯π and C—Br⋯π inter­actions

An autonomous intelligent gateway infrastructure for in-field processing in precision viticulture

Article in PressWireless sensor networks have found multiple applications in precision viticulture. Despite the steady progress in sensing devices and wireless technologies, some of the crucial items needed to improve the usability and scalability of the networks, such as gateway infrastructures and in-field processing, have been comparatively neglected. This paper describes the hardware, communication capabilities and software architecture of an intelligent autonomous gateway, designed to provide the necessary middleware between locally deployed sensor networks and a remote location within the whole-farm concept. This solar-powered infrastructure, denoted by iPAGAT (Intelligent Precision Agriculture Gateway), runs an aggregation engine that fills a local database with environmental data gathered by a locally deployed ZigBee wireless sensor network. Aggregated data are then retrieved by external queries over the built-in data integration system. In addition, embedded communication capabilities, including Bluetooth, IEEE 802.11 and GPRS, allow local and remote users to access both gateway and remote data, as well as the Internet, and run site-specific management tools using authenticated smartphones. Field experiments provide convincing evidence that iPAGAT represents an important step forward in the development of distributed service-oriented information systems for precision viticulture applications.The authors would like to acknowledge the Portuguese Foundation of Science and Technology (FCT), and Spanish Seneca Foundation Centre for Research Coordination that partially sponsors this research work through the scholarships references SFRH/BD/38759/2007 and 02998-PI-05, respectively