New insights into bacterial cellulose materials: production and modification strategies

Komagataeibacter xylinus cultures produced high amount of bacterial cellulose (BC), which has a structure of nanoporous network of interlaced fibers. When the culture is performed under static experimental conditions, a membrane with characteristics of highly hydrated hydrogel and good mechanical properties is obtained with promissory applications in the biomedical field. Bacterial cellulose films can be used from dermal dressing and even as a controlled drug release system. Besides, stirred cultures of K. xylinus produced amorphous cellulose structures dispersed in the medium with physical and mechanical characteristics different from the membrane. In addition, new properties of BC can be obtained or added if the hydrogel is mixed with other compounds or modified post-purification using both organic and inorganic compounds.

Nanobiotechnology solutions against aedes aegypti

United Nations Children's Fund (UNICEF)/United Nations Development Programme (UNDP)/World Bank/World Health Organization (WHO) implemented the Training in Tropical Diseases (TDR) program with excellent results; however, due to current challenges, this active program requires new and innovative solutions. Nowadays, Aedes aegyptis-borne diseases can be added among neglected diseases. Surveillance and control must be considered owing to a great risk of infection with dengue, chikungunya and zika viruses. Although investigations on several vaccines are in progress, new insights in term of development of drugs that evade from resistance are of paramount importance. Nanobiotechnology appears as one of the most innovative strategy in the search of new uses for old pharmaceuticals or in the development of innovative and intelligent nanomedicines for neglected diseases. Liposomes, solid lipid nanoparticles, nanoemulsions, polymeric nanoparticles, metallic nanoparticles, quantum dots, carbon dots and carbon nanotubes were the focus of the current advances. In this direction, we have focused this overview on new advances in diagnostic assays as nanobiosensors, antivirus and nanoinsecticides on Aedes aegyptis control27711391149CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçã

Bionanoparticles, a green nanochemistry approach

Background: In the past decade, considerable attention has been paid for the development of novel strategies for the synthesis of different kind of nano-objects. Most of the current strategies are usually working by the use physical or chemical principles to develop a myriad of nano-objects with multiple applications. Main fields of nanotechnology applications range from catalysis, micro- and nano-electronics (semiconductors, single electrons transistors), non-linear optic devices, photo-electrochemistry to biomedicine, diagnostics, foods and environment, chemical analysis and others. Results: Two main avenues for nanoparticles synthesis: cell-free extract and cell cultivation have been reported. The state of art of both biotechnological approaches for different type nanoparticles are reviewed in this work. Conclusions: Nanotechnology is a revolutionary field just at its onset, the trend in the next decades being its integration with the green chemistry approach. Several strategies involving exhaustive strain selection, cultivation modes, recombinant gene expression, metabolic engineering, protein re-design and re-engineering, and predictive modeling will allow to create nanobioreactors, a new nanobiotechnology arena with a high potential impact in many fields

Non-Aqueous Biocatalysis in Homogeneous Solvent Systems

Enzymes are highly specific catalysts that typically function in aqueous solvents. However, many enzymes retain their catalytic activities at high concentrations in non- aqueous environments, including neat hydrophilic organic solvents. In fact, enzymes can be used to carry out reactions in organic solvents that are not possible in aqueous systems. Therefore, biocatalysis in homogenous non-aqueous solvents offers possibilities for producing useful chemicals and several synthetic reactions have already been developed using this type of system. The current review discusses factors that influence enzyme catalysis in non-aqueous solvents such us water content, solvent concentration, interaction of solvent with protein structure, stability and activity. Also, new strategies for non-conventional biocatalysis using extremophiles and ionic solvents are mentioned

DESARROLLO Y OPTIMIZACIÓN DE LOS PROCESOS BIOTECNOLÓGICOS DE PRODUCCIÓN DE CELULOSA BACTERIANA PARA POTENCIAL TRATAMIENTO DE AFECCIONES DÉRMICAS

En mi trabajo de investigación estudio el proceso biotecnológico de producción de celulosa bacteriana (CB) por parte de Komagataeibacter spp. El cultivo estático de cepas del género Komagataeibacter da como resultado CB en forma de una membrana flotante mientras que cultivo agitado da lugar a CB en forma de pequeñas esferas/fibras irregulares en el medio de cultivo. Particularmente las membranas conforman un hidrogel con muy buenas propiedades aplicables en biomedicina, donde se la utiliza como vendaje para heridas, soporte en ingeniería de tejidos, sistema de liberación controlada de fármacos, entre otros. Además, la CB puede modificarse químicamente o bien incorporársele otros materiales como polímeros, materiales inorgánicos, nanopartículas, arcillas, etc. De este modo, adquiere nuevas características, tales como actividad antimicrobiana, o se ven mejoradas sus propiedades (mecánicas, por ejemplo). Por otra parte, la CB puede ser empleada como fuente para la síntesis de distintos nanomateriales, al hidrolizarse selectivamente las regiones amorfas de la celulosa, seleccionando las cristalinas. Así, es que surgen los nanocristales de celulosa (NCC) y las nanofibras de celulosa (NFC), que entre si se diferencian en longitud quedando en las NFC algunas porciones amorfas.  Ambos presentan una alta superficie específica lo que posibilita su modificación química superficial eficiente. Este tipo de reacciones permiten que los NCC/NFC se asocien con distintos tipos de moléculas, además de poder alterar la cinética de liberación de las mismas. También, mejoran las propiedades mecánicas de matrices poliméricas a las que son agregados. Por ello, se han utilizado en tintas para fabricar estructuras complejas en impresión 3D. De hecho, la celulosa no solo encuentra su aplicación en el campo de la bioimpresión 3D bajo la forma de NCC/NFC, sino que se han diseñado tintas capaces de inmovilizar a la cepa productora para que sintetice CB con formas previamente diseñadas. En este marco, en el presente trabajo se aborda la producción de CB en distintas variantes (membranas, NCC/NFC y microfibras para diseñar matrices por impresión 3D), que posteriormente, se modificarán para otorgarles nuevas y/o mejores propiedades orientadas al potencial tratamiento de afecciones dérmicas. Dentro de las modificaciones planeadas, se incluye la derivatización química, la asociación con otros materiales como polímeros y arcillas, la inclusión de moléculas con actividad biológica, etc

Enkapsulacija askorbinske kiseline u hidrofobnom silikagelu

Self-assembled hybrid organo-silica sol-gel materials are rapidly expanding for newand novel applications. The microporous solid silica matrix was used as a carrier for the controlled release of ascorbic acid (AA), selected as cargo molecule. One-step synthesis procedure was optimized for the preparation of silica–molecule composites by using tetraethoxysilane and methyltrimethoxysilane as precursors. The hydrophobic silica xerogel matrices were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. Specific surface area and porosity parameters were determined by Brunauer-Emmett-Teller (BET) technique and the matrix surface morphology by scanning electron microscopy (SEM). The observed release pattern could be interesting for the development of AA-fortified food and for use in food packaging.Hibridni, organsko-silikatni sol-gel materijal sve se više primjenjuje u prehrambenoj industriji. Stoga je kao nosač za kontrolirano otpuštanje askorbinske kiseline upotrijebljen mikroporozni čvrsti silikatni matriks. Optimirana je jednostupanjska sinteza kojom su dobiveni silikatni kompoziti uz pomoć prekurzora: tetraetoksisilana i metiltrimetoksisilana. Matriksi su hidrofobnog silikagela okarakterizirani Fourier transformiranom infracrvenom spektroskopijom (FTIR) i difrakcijom X-zraka. Specifična površina i poroznost matriksa ispitane su Brunaer-Emmett-Teller (BET) metodom, dok su morfološka svojstva površine matriksa određena skenirajućim elektronskim mikroskopom (SEM). Utvrđeno je da se askorbinska kiselina ovako može upotrijebiti za proizvodnju hrane s dodanom vrijednošću, te za pakiranje prehrambenih proizvoda

Sinteza sustava upravljanja s proporcionalno-derivacijskim regulatorom zasnovana na neizrazitim diferencijalnim jednadžbama

This paper reports a fuzzy differential equations approach for the modeling of initial condition uncertainty for a proportional derivative closed-loop control of a direct current motor. Uncertainties are considered on the precision of the sensing devices installed on a driver. The closed-loop system is designed for a plant modeled with fuzzy differential equations. Satisfactory analytic and numerical results for the position regulation problem for ideal case and also considering perturbed initial conditions are reported.U radu je razvijen postupak sinteze proporcionalno-derivacijskog regulatora za upravljanje istosmjernim motorom s neizrazitim (engl. fuzzy) početnim uvjetima zasnovane na neizrazitim diferencijalnim jednadžbama. Pritom je uzeta u obzir nesigurnost određena mjernom preciznošću senzora. U predloženom postupku se zatvoreni regulacijski krug dizajnira korištenjem neizrazitih diferencijalnih jednadžbi. Primjenom projektiranog regulatora na probleme pozicioniranja u idealnom slučaju te u slučaju koji uzima u obzir perturbirane početne uvjete ostvareni su zadovoljavajući analitički i numerički rezultati

Enkapsulacija askorbinske kiseline u hidrofobnom silikagelu

Self-assembled hybrid organo-silica sol-gel materials are rapidly expanding for newand novel applications. The microporous solid silica matrix was used as a carrier for the controlled release of ascorbic acid (AA), selected as cargo molecule. One-step synthesis procedure was optimized for the preparation of silica–molecule composites by using tetraethoxysilane and methyltrimethoxysilane as precursors. The hydrophobic silica xerogel matrices were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. Specific surface area and porosity parameters were determined by Brunauer-Emmett-Teller (BET) technique and the matrix surface morphology by scanning electron microscopy (SEM). The observed release pattern could be interesting for the development of AA-fortified food and for use in food packaging.Hibridni, organsko-silikatni sol-gel materijal sve se više primjenjuje u prehrambenoj industriji. Stoga je kao nosač za kontrolirano otpuštanje askorbinske kiseline upotrijebljen mikroporozni čvrsti silikatni matriks. Optimirana je jednostupanjska sinteza kojom su dobiveni silikatni kompoziti uz pomoć prekurzora: tetraetoksisilana i metiltrimetoksisilana. Matriksi su hidrofobnog silikagela okarakterizirani Fourier transformiranom infracrvenom spektroskopijom (FTIR) i difrakcijom X-zraka. Specifična površina i poroznost matriksa ispitane su Brunaer-Emmett-Teller (BET) metodom, dok su morfološka svojstva površine matriksa određena skenirajućim elektronskim mikroskopom (SEM). Utvrđeno je da se askorbinska kiselina ovako može upotrijebiti za proizvodnju hrane s dodanom vrijednošću, te za pakiranje prehrambenih proizvoda

On error-based step size control for discontinuous Galerkin methods for compressible fluid dynamics

We study temporal step size control of explicit Runge-Kutta methods for compressible computational fluid dynamics (CFD), including the Navier-Stokes equations and hyperbolic systems of conservation laws such as the Euler equations. We demonstrate that error-based approaches are convenient in a wide range of applications and compare them to more classical step size control based on a Courant-Friedrichs-Lewy (CFL) number. Our numerical examples show that error-based step size control is easy to use, robust, and efficient, e.g., for (initial) transient periods, complex geometries, nonlinear shock capturing approaches, and schemes that use nonlinear entropy projections. We demonstrate these properties for problems ranging from well-understood academic test cases to industrially relevant large-scale computations with two disjoint code bases, the open source Julia packages Trixi.jl with OrdinaryDiffEq.jl and the C/Fortran code SSDC based on PETSc

Design of an Intelligent Front-End Signal Conditioning Circuit for IR Sensors

This paper presents the design of an intelligent front-end signal conditioning system for IR sensors. The system has been developed as an interface between a PbSe IR sensor matrix and a TMS320C67x digital signal processor. The system architecture ensures its scalability so it can be used for sensors with different matrix sizes. It includes an integrator based signal conditioning circuit, a data acquisition converter block, and a FPGA based advanced control block that permits including high level image preprocessing routines such as faulty pixel detection and sensor calibration in the signal conditioning front-end. During the design phase virtual instrumentation technologies proved to be a very valuable tool for prototyping when choosing the best A/D converter type for the application. Development time was significantly reduced due to the use of this technology