Modelo para elaboração de políticas de preservação digital de documentos de arquivo por instituições de ensino superior: o caso da Unesp / Model for the elaboration of policies for the digital preservation of records by higher education institutions: the case of Unesp / Modelo para la elaboración de políticas de preservación digital de documentos de archivo por instituciones de educación superior: el caso de la Unesp

Um dos desafios das mudanças e evoluções das tecnologias de informação e comunicação (TIC) em corporações é a preservação das informações digitais. Entre as corporações com grande geração de informações digitais estão as universidades. Neste artigo, é apresentada uma estratégia para se elaborar uma política de preservação digital no bojo de uma política arquivística direcionada para a manutenção da autenticidade dos documentos de arquivo. O objetivo é expor um modelo para elaboração de políticas de preservação digital de documentos de arquivo por instituições de ensino superior (IES), com os elementos que devem compô-las, a partir da literatura estudada e da política elaborada e aprovada na Universidade Estadual Paulista (Unesp). São apresentados os conceitos relacionados à política arquivística para a preservação digital de documentos de arquivo, sua definição, seus aspectos e elementos. Concluiu-se que o modelo pode ser adaptado para outros objetos digitais, bem como para outras instituições.

One of the challenges of the changes and evolutions of the information and communication technology (ICT) in corporations is the preservation of digital information. The universities are among the corporations with a large generation of digital information. This article presents a strategy for the elaboration of a digital preservation policy, in the context of an archival policy which is aimed at maintaining the authenticity of archival documents. The objective of this article is to present a model so that the higher education institutions could making policies for the digital preservation of their archival documents, showing the elements that must compose each one, based on the studied literature and on the policy elaborated in Unesp and which was officially approved by that institution. Concepts related to archival policy for the digital preservation of archival documents, their definition, aspects and elements are presented here. It was concluded that the model can be adapted for other digital objects, as well as for other institutions.

Uno de los desafíos de los cambios y la evolución de las TIC en las corporaciones es la preservación de informaciones digitales. Entre las corporaciones con una gran generación de información digital se encuentran las universidades. En este artículo, se presenta una estrategia para elaborar una política de preservación digital, en medio de una política de archivo dirigida a mantener la autenticidad de los documentos de archivo. El objetivo del artículo es presentar un modelo para la elaboración de políticas de preservación digital de documentos de archivo por instituciones de enseñanza superior, con los elementos que deben componerlas, basado en la literatura estudiada y en la política desarrollada y aprobada en la Unesp. Se presentan conceptos relacionados con la política de archivo para la preservación digital de documentos de archivo, su definición, aspectos y elementos. Se concluyó que este modelo puede adaptarse para otros objetos digitales, así como para otras instituciones.

Beyond disease, how biomedical engineering can improve global health.

Biomedical engineering tools can be harnessed to address some of the world's most challenging nondisease-focused problems.

Breakdown into nanoscale of graphene oxide: confined hot spot atomic reduction and fragmentation.

Nano-graphene oxide (nano-GO) is a new class of carbon based materials being proposed for biomedical applications due to its small size, intrinsic optical properties, large specific surface area, and easy to functionalize. To fully exploit nano-GO properties, a reproducible method for its production is of utmost importance. Herein we report, the study of the sequential fracture of GO sheets onto nano-GO with controllable lateral width, by a simple, and reproducible method based on a mechanism that we describe as a confined hot spot atomic fragmentation/reduction of GO promoted by ultrasonication. The chemical and structural changes on GO structure during the breakage were monitored by XPS, FTIR, Raman and HRTEM. We found that GO sheets starts breaking from the defects region and in a second phase through the disruption of carbon bonds while still maintaining crystalline carbon domains. The breaking of GO is accompanied by its own reduction, essentially by the elimination of carboxylic and carbonyl functional groups. Photoluminescence and photothermal studies using this nano-GO are also presented highlighting the potential of this nanomaterial as a unique imaging/therapy platform.

Tuning heterogeneous poly(dopamine) structures and mechanics: in silico covalent cross-linking and thin film nanoindentation.

Mussel-inspired synthetic poly(dopamine) thin films from dihydroxyphenylalanine (DOPA) and lysine, structurally similar to natural melanin, have drawn extensive interest as a versatile surface functionalization and coating material for use in a broad range of applications. In order to gain a better understanding of its complex and heterogeneous polymeric structure and mechanical properties, we report a computational model of poly(dopamine) by mimicking the polymerization process of the intermediate oxidized product of dopamine, 5,6-dihydroxyindole (DHI), via controlled in silico covalent cross-linking under the two most possible reaction schemes proposed in experiments. To validate our results using experiment, we synthesize poly(dopamine) thin films and perform experimental nanoindentations on the film. We observe an overall linear behavior for Young's modulus as a function of the degree of cross-linking, demonstrating the possibility of enhancing the mechanical robustness of poly(dopamine) materials by increasing the extent of polymerization. At the highest degree of polymerization considered (70%), the model mimics the linear tetrameric model for poly(dopamine) and melanin. At this degree of polymerization, we find a Young's modulus of 4.1-4.4 GPa, in agreement with our nanoindentation results of 4.3-10.5 GPa, previous experiments for natural melanin, as well as simulation results for the cyclic tetrameric melanin model (Chen et al., ACS Nano, 2013). Our results suggest that the non-covalent DHI aggregate model might not be appropriate to represent the structure of poly(dopamine) and melanin-like materials, since it gives a much smaller Young's modulus than the experimental lower bound. Our model not only nicely complements the previous computational work, but also provides new computational tools to study the heterogeneous structural and physicochemical properties of poly(dopamine) and melanin, as well as their formation pathways.

Enhanced thermal conductivity and viscosity of nanodiamond-nickel nanocomposite nanofluids.

We report a new type of magnetic nanofluids, which is based on a hybrid composite of nanodiamond and nickel (ND-Ni) nanoparticles. We prepared the nanoparticles by an in-situ method involving the dispersion of caboxylated nanodiamond (c-ND) nanoparticles in ethylene glycol (EG) followed by mixing of nickel chloride and, at the reaction temperature of 140°C, the use of sodium borohydrate as the reducing agent to form the ND-Ni nanoparticles. We performed their detailed surface and magnetic characterization by X-ray diffraction, micro-Raman, high-resolution transmission electron microscopy, and vibrating sample magnetometer. We prepared stable magnetic nanofluids by dispersing ND-Ni nanoparticles in a mixture of water and EG; we conducted measurements to determine the thermal conductivity and viscosity of the nanofluid with different nanoparticles loadings. The nanofluid for a 3.03% wt. of ND-Ni nanoparticles dispersed in water and EG exhibits a maximum thermal conductivity enhancement of 21% and 13%, respectively. For the same particle loading of 3.03% wt., the viscosity enhancement is 2-fold and 1.5-fold for water and EG nanofluids. This particular magnetic nanofluid, beyond its obvious usage in heat transfer equipment, may find potential applications in such diverse fields as optics and magnetic resonance imaging.

Nanodiamonds activate blood platelets and induce thromboembolism.

AIM: Nanodiamonds (NDs) have been evaluated for a wide range of biomedical applications. Thus, thorough investigation of the biocompatibility of NDs has become a research priority. Platelets are highly sensitive and are one of the most abundant cell types found in blood. They have a central role in hemostasis and arterial thrombosis. In this study, we aim to investigate the direct and acute effects of carboxylated NDs on platelet function. METHODS: In this study, pro-coagulant parameters such as platelet aggregability, intracellular Ca(2+) flux, mitochondrial transmembrane potential (ΔΨm), generation of reactive oxygen species, surface exposure of phosphatidylserine, electron microscopy, cell viability assay and in vivo thromboembolism were analyzed in great detail. RESULTS: Carboxylated NDs evoked significant activation of human platelets. When administered intravenously in mice, NDs were found to induce widespread pulmonary thromboembolism, indicating the remarkable thrombogenic potential of this nanomaterial. CONCLUSION: Our findings raise concerns regarding the putative biomedical applications of NDs pertaining to diagnostics and therapeutics, and their toxicity and prothrombotic properties should be critically evaluated.

Comparison of synthetic dopamine-eumelanin formed in the presence of oxygen and Cu2+ cations as oxidants.

Eumelanin is not only a ubiquitous pigment among living organisms with photoprotective and antioxidant functions, but is also the subject of intense interest in materials science due to its photoconductivity and as a possible universal coating platform, known as "polydopamine films". The structure of eumelanin remains largely elusive, relying either on a polymeric model or on a heterogeneous aggregate structure. The structure of eumelanin as well as that of the closely related "polydopamine films" can be modified by playing on the nature of the oxidant used to oxidize dopamine or related compounds. In this investigation, we show that dopamine-eumelanins produced from dopamine in the presence of either air (O2 being the oxidant) or Cu(2+) cations display drastically different optical and colloidal properties in relation with a different supramolecular assembly of the oligomers of 5,6 dihydroxyindole, the final oxidation product of dopamine. The possible origin of these differences is discussed on the basis of Cu(2+) incorporation in Cu dopamine-eumelanin.

Evaluation of the in vitro biocompatibility of PMMA/high-load HA/carbon nanostructures bone cement formulations.

Although commercially-available poly(methyl methacrylate) bone cement is widely used in total joint replacements, it has many shortcomings, a major one being that it does not osseointegrate with the contiguous structures. We report on the in vitro evaluation of the biocompatibility of modified formulations of the cement in which a high loading of hydroxyapatite (67 wt/wt%), an extra amount of benzoyl peroxide, and either 0.1 wt/wt% functionalized carbon nanotubes or 0.5 wt/wt% graphene oxide was added to the cement powder and an extra amount of dimethyl-p-toluidiene was added to the cement's liquid monomer. This evaluation was done using mouse L929 fibroblasts and human Saos-2 osteoblasts. For each combination of cement formulation and cell type, there was high cell viability, low apoptosis, and extensive spread on disc surfaces. Thus, these two cement formulations may have potential for use in the clinical setting.

Nano-graphene oxide: a potential multifunctional platform for cancer therapy.

Nano-GO is a graphene derivative with a 2D atomic layer of sp² bonded carbon atoms in hexagonal conformation together with sp³ domains with carbon atoms linked to oxygen functional groups. The supremacy of nano-GO resides essentially in its own intrinsic chemical and physical structure, which confers an extraordinary chemical versatility, high aspect ratio and unusual physical properties. The chemical versatility of nano-GO arises from the oxygen functional groups on the carbon structure that make possible its relatively easy functionalization, under mild conditions, with organic molecules or biological structures in covalent or non-covalent linkage. The synergistic effects resulting from the assembly of well-defined structures at nano-GO surface, in addition to its intrinsic optical, mechanical and electronic properties, allow the development of new multifunctional hybrid materials with a high potential in multimodal cancer therapy. Herein, a comprehensive review of the fundamental properties of nano-GO requirements for cancer therapy and the first developments of nano-GO as a platform for this purpose is presented.

Morphological, compositional and ultrastructural changes in the Scrobicularia plana shell in response to environmental mercury--an indelible fingerprint of metal exposure?

The study aimed to assess morphological, structural and compositional alterations in Scrobicularia plana nacre environmentally exposed to mercury in order to seek out the possibility of the assessed alterations as a monitoring tool to handle complexity and interactions of metals in the environment involving a non-invasive methodology. Bivalves were collected from a mercury contaminated site (Laranjo basin - Ria de Aveiro, Portugal) and a reference site in the same aquatic system. The combination of scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) technique depicted a sheet like morphology of bivalve nacre collected from the reference site. Moreover, EDS plot exhibited the presence of potassium, oxygen, calcium, and carbon elements. Shells collected from the contaminated area depicted lamellar patches like structures with particle like morphology composition. SEM images corresponding to the elemental analysis by EDS plot clearly denoted the presence of mercury. SEM images from the other locations of the contaminated shells depicted large surface area, a broken or ruptured symmetry of organic matrix as well as crack-like gaps. The influence of environmental mercury affecting the surface morphology of S. plana nacre showed dimple like morphology (as proved by transmission electron microscopy, TEM). The possible explanation may be the replacement of calcium elements with other elements or alloys from the nacre composite collected from contaminated region. Therefore, the nacre fingerprint may be useful as innovative knowledge and applicable tool aiming at risk reduction from noxious mercury present in the environment. Overall results suggested the use of shell as an indelible fingerprint of metal exposure.

Self-assembly of tetramers of 5,6-dihydroxyindole explains the primary physical properties of eumelanin: experiment, simulation, and design.

Eumelanin is a ubiquitous pigment in nature and has many intriguing physicochemical properties, such as broad-band and monotonous absorption spectrum, antioxidant and free radical scavenging behavior, and strong nonradiative relaxation of photoexcited electronic states. These properties are highly related to its structural and mechanical properties and make eumelanin a fascinating candidate for the design of multifunctional nanomaterials. Here we report joint experimental-computational investigation of the structural and mechanical properties of eumelanin assemblies produced from dopamine, revealing that the mass density of dry eumelanin is 1.55 g/cm³ and its Young's modulus is ≈5 GPa. We also find that wet eumelanin has a lower mass density and Young's modulus depending on the water-to-melanin ratio. Most importantly, our data show that eumelanin molecules tend to form secondary structures based on noncovalent π stacking in both dry and wet conditions, with an interlayer distance between eumelanin molecules of 3.3 Å. Corresponding transmission electron microscope images confirm the supramolecular organization predicted in our simulations. Our simulations show that eumelanin is an isotropic material at a larger scale when eumelanin molecules are randomly oriented to form secondary structures. These results are in good agreement with experimental observations, density functional theory calculations, and bridge the gap between earlier experimental and small-scale quantum mechanical studies of eumelanin. We use the knowledge acquired from the simulations to select a partner molecule, a cationic phthalocyanine, allowing us to produce layer-by-layer films containing eumelanin that display an electrical conductivity 5 orders of magnitudes higher than that of pure eumelanin films.

Nanotechnology in automotive industry: research strategy and trends for the future-small objects, big impacts.

The goal of this paper is to emphasize and present briefly the nanotechnology science and its potential impact on the automotive industry in order to improve the production of recent models with an optimization of the safety performance and a reduction in the environmental impacts. Nanomaterials can be applied in car bodies as light weight constructions without compromising the stiffness and crashwortiness, which means less material and less fuel consumption. This paper outlines the progress of nanotechnology applications into the safety features of more recent vehicle models and fuel efficiency, but also emphasis the importance of sustainable development on the application of these technologies and life cycle analysis of the considered materials, in order to meet the society trends and customers demands to improve ecology, safety and comfort.

Fabrication of a glucose biosensor based on citric acid assisted cobalt ferrite magnetic nanoparticles.

A novel and practical glucose biosensor was fabricated with immobilization of Glucose oxidase (GOx) enzyme on the surface of citric acid (CA) assisted cobalt ferrite (CF) magnetic nanoparticles (MNPs). This innovative sensor was constructed with glassy carbon electrode which is represented as (GOx)/CA-CF/(GCE). An explicit high negative zeta potential value (-22.4 mV at pH 7.0) was observed on the surface of CA-CF MNPs. Our sensor works on the principle of detection of H2O2 which is produced by the enzymatic oxidation of glucose to gluconic acid. This sensor has tremendous potential for application in glucose biosensing due to the higher sensitivity 2.5 microA/cm2-mM and substantial increment of the anodic peak current from 0.2 microA to 10.5 microA.

Local nanoelectromechanical properties of multiferroics Gd-doped BiFeO3-BaTiO3 solid solution.

Bi(1-x-y)GdxBayFe(1-y)TiyO3 (x = 0.1 and y = 0.1, 0.2, 0.3) solid solutions have been prepared via solid state reaction method with the aim to obtaining magnetoelectric coupling (i.e., linear relation between magnetization and electric field) at room temperature. Optimum calcination and sintering strategies for obtaining pure perovskite phase, high density ceramics and homogeneous microstructures have been determined. The maximum ferroelectric transition temperature (Tc) of this system was 150-170 degrees C with the dielectric constant peak of 2300 at 100 kHz for y = 0.1. Well saturated piezoelectric loops were observed for all composition indicating room temperature ferroelectricity. Hardness and Young's modulus decrease with depth and with increasing concentration y.

Wet-chemical green synthesis of L-lysine amino acid stabilized biocompatible iron-oxide magnetic nanoparticles.

In this paper, we report a novel method for the synthesis of L-Lysine (lys) amino acid coated maghemite (gamma-Fe2O3) magnetic nanoparticles (MNPs). The facile and cost effective method permitted preparation of the high-quality superparamagnetic gamma-Fe2O3 MNPs with hydrophilic and biocompatible nature. For this work, first we synthesized magnetite phase Fe3O4/lys by wet chemical method and oxidized to y-Fe2O3 in controlled oxidizing environment, as evidenced by XRD and VSM magnetometry. The crystallite size and magnetization of gamma-Fe2O3/lys MNPs was found to be 14.5 nm, 40.6 emu/gm respectively. The surface functionalization by L-lysine amino acid and metal-ligand bonding was also confirmed by FTIR spectroscopy. The hydrodynamic diameter, colloidal stability and surface charge on MNPs were characterized by DLS and zeta potential analyser.

Graphene oxide and hydroxyapatite as fillers of polylactic acid nanocomposites: preparation and characterization.

Graphene and its derivatives have attracted great research interest for their potential applications in electronics, energy, materials and biomedical areas. When incorporated appropriately, these atomically thin carbon sheets are expected to improve physical properties of host polymers at extremely small loading. Herein, we report a novel two-step method for the preparation of PLLA/Hap/graphene oxide nanocomposites with augmented mechanical properties when compared to PLLA/Hap and neat PLLA. The presence of graphene oxide (GO) had a positive effect on the dispersion of hydroxyapatite particles on the polymeric matrix contributing for a good homogeneity of the final nanocomposite. PLLA nanocomposites prepared with 30% (w/w) of Hap and 1% (w/w) of GO showed the highest hardness and storage modulus values indicating an efficient load transfer between the fillers and the PLLA matrix. These materials may find interesting biomedical applications as for example bone screws. The following step on the study of these materials will be in vitro tests to access the biocompatibility of these new nanocomposites.

Temperature dependence of the Henry's law constant for hydrogen storage in NaA zeolites: a Monte Carlo simulation study.

Grand canonical Monte Carlo simulations of hydrogen adsorption in zeolites NaA were carried out for a wide range of temperatures between 77 and 300 K and pressures up to 180 MPa. A potential model was used that comprised of three main interactions: van der Waals, coulombic and induced polarization by the electric field in the system. The computed average number of adsorbed molecules per unit cell was compared with available results and found to be in agreement in the regime of moderate to high pressures. The particle insertion method was used to calculate the Henry coefficient for this model and its dependence on temperature.

Large-area high-throughput synthesis of monolayer graphene sheet by Hot Filament Thermal Chemical Vapor Deposition.

We report hot filament thermal CVD (HFTCVD) as a new hybrid of hot filament and thermal CVD and demonstrate its feasibility by producing high quality large area strictly monolayer graphene films on Cu substrates. Gradient in gas composition and flow rate that arises due to smart placement of the substrate inside the Ta filament wound alumina tube accompanied by radical formation on Ta due to precracking coupled with substrate mediated physicochemical processes like diffusion, polymerization etc., led to graphene growth. We further confirmed our mechanistic hypothesis by depositing graphene on Ni and SiO(2)/Si substrates. HFTCVD can be further extended to dope graphene with various heteroatoms (H, N, and B, etc.,), combine with functional materials (diamond, carbon nanotubes etc.,) and can be extended to all other materials (Si, SiO(2), SiC etc.,) and processes (initiator polymerization, TFT processing) possible by HFCVD and thermal CVD.

Graphene oxide versus functionalized carbon nanotubes as a reinforcing agent in a PMMA/HA bone cement.

Graphene oxide (GO) and functionalized carbon nanotubes (f-CNTs) (each in the concentration range of 0.01-1.00 wt/wt%) were investigated as the reinforcing agent in a poly(methyl methacrylate) (PMMA)/hydroxyapatite (HA) bone cement. Mixed results were obtained for the changes in the mechanical properties determined (storage modulus, bending strength, and elastic modulus) for the reinforced cement relative to the unreinforced counterpart; that is, some property changes were increased while others were decreased. We postulate that this outcome is a consequence of the fact that each of the nanofillers hampered the polymerization process in the cement; specifically, the nanofiller acts as a scavenger of the radicals produced during polymerization reaction due to the delocalized π-bonds. Results obtained from the chemical structure and polymer chain size distribution determined, respectively, by nuclear magnetic resonance and size exclusion chromatography analysis, on the polymer extracted from the specimens support the postulated mechanism. Furthermore, in the case of the 0.5 wt/wt% GO-reinforced cement, we showed that when the concentration of the radical species in the PMMA bone cement was doubled, mechanical properties markedly improved (relative to the value in the unreinforced cement), suggesting suppression of the aforementioned scavenger activity.

Amine-modified graphene: thrombo-protective safer alternative to graphene oxide for biomedical applications.

Graphene and its derivatives have attracted significant research interest based on their application potential in different fields including biomedicine. However, recent reports from our laboratory and elsewhere have pointed to serious toxic effects of this nanomaterial on cells and organisms. Graphene oxide (GO) was found to be highly thrombogenic in mouse and evoked strong aggregatory response in human platelets. As platelets play a central role in hemostasis and thrombus formation, thrombotoxicity of GO potentially limits its biomedical applications. Surface chemistry of nanomaterials is a critical determinant of biocompatibility, and thus differentially functionalized nanomaterials exhibit varied cellular toxicity. Amine-modified carbon nanotubes have recently been shown to possess cytoprotective action, which was not exhibited by their relatively toxic carboxylated counterparts. We, therefore, evaluated the effect of amine modification of graphene on platelet reactivity. Remarkably, our results revealed for the first time that amine-modified graphene (G-NH(2)) had absolutely no stimulatory effect on human platelets nor did it induce pulmonary thromboembolism in mice following intravenous administration. Further, it did not evoke lysis of erythrocytes, another major cellular component in blood. These findings contrasted strikingly the observations with GO and reduced GO (RGO). We conclude that G-NH(2) is not endowed with thrombotoxic property unlike other commonly investigated graphene derivatives and is thus potentially safe for in vivo biomedical applications.