New biomaterials for packaging: a green approach to biopolymers and biocomposites

The impellent global environmental issues related to plastic materials can be addressed by following two different approaches: i) the development of synthetic strategies towards novel bio-based polymers, deriving from biomasses and thus identifiable as CO2-neutral materials, and ii) the development of new plastic materials, such as biocomposites, which are bio-based and biodegradable and therefore able to counteract the accumulation of plastic waste. In this framework, this dissertation presents extensive research efforts have been devoted to the synthesis and characterization of polyesters based on various bio-based monomers, including ω-pentadecalactone, vanillic acid, 2,5-furan dicarboxylic acid, and 5-hydroxymethylfurfural. With the aim of achieving high molecular weight polyesters, different synthetic strategies have been used as melt polycondensation, enzymatic polymerization, ring-opening polymerization and chain extension reaction. In particular, poly(ethylene vanillate) (PEV), poly(ω-pentadecalactone) (PPDL), poly(ethylene vanillate-co-pentadecalactone) (P(EV-co-PDL)), poly(2-hydroxymethyl 5-furancarboxylate) (PHMF), poly(ethylene 2,5-furandicarboxylate) (PEF) with different amount of diethylene glycol (DEG) unit amount, poly(propylene 2,5-furandicarboxylate) (PPF), poly(hexamethylene 2,5-furandicarboxylate), (PHF) have been prepared and extensively characterized. To improve the lacks of poly(hydroxybutyrate-co-valerate) (PHBV), its minimal formulations with natural additives and its blending with medium chain length PHAs (mcl-PHAs) have been tested. Additionally, this dissertation presents new biocomposites based on polylactic acid (PLA), poly(butylene succinate) (PBS), and PHBV, which are polymers both bio-based and biodegradable. To maintain their biodegradability only bio-fillers have been taken into account as reinforcing agents. Moreover, the commitment to sustainability has further limited the selection and led to the exclusive use of agricultural waste as fillers. Detailly, biocomposites have been obtained and discussed by using the following materials: PLA and agro-wastes like tree pruning, potato peels, and hay leftovers; PBS and exhausted non-compliant coffee green beans; PHBV and industrial starch extraction residues.

Reduced Lrp6 Expression And Increase In The Interaction Of Gsk3β With P53 Contribute To Podocyte Apoptosis In Diabetes Mellitus And Are Prevented By Green Tea.

In diabetes mellitus (DM), podocyte apoptosis leads to albuminuria and nephropathy progression. Low-density lipoprotein receptor-related protein 6 (LRP6) is WNT pathway receptor that is involved in podocyte death, adhesion and motility. Glycogen synthase kinase 3 (GSK3) interaction with p53 (GSK3-p53) promotes apoptosis in carcinoma cells. It is unknown if GSK3-p53 contributes to podocyte apoptosis in DM. In experimental DM, green tea (GT) reduces albuminuria by an unknown mechanism. In the present study, we assessed the role of the GSK3β-p53 in podocyte apoptosis and the effects of GT on these abnormalities. In diabetic spontaneously hypertensive rats (SHRs), GT prevents podocyte's p-LRP6 expression reduction, increased GSK3β-p53 and high p53 levels. In diabetic SHR rats, GT reduces podocyte apoptosis, foot process effacement and albuminuria. In immortalized mouse podocytes (iMPs), high glucose (HG), silencing RNA (siRNA) or blocking LRP6 (DKK-1) reduced p-LRP6 expression, leading to high GSK3β-p53, p53 expression, apoptosis and increased albumin influx. GSK3β blockade by BIO reduced GSK3β-p53 and podocyte apoptosis. In iMPs under HG, GT reduced apoptosis and the albumin influx by blocking GSK3β-p53 following the rise in p-LRP6 expression. These effects of GT were prevented by LRP6 siRNA or DKK-1. In conclusion, in DM, WNT inhibition, via LRP6, increases GSK3β-p53 and podocyte apoptosis. Maneuvers that inactivate GSK3β-p53, such as GT, may be renoprotective in DM.

Spin-polarized current and shot noise in the presence of spin flip in a quantum dot via nonequilibrium Green's functions

Using nonequilibrium Green's functions we calculate the spin-polarized current and shot noise in a ferromagnet-quantum-dot-ferromagnet system. Both parallel (P) and antiparallel (AP) magnetic configurations are considered. Coulomb interaction and coherent spin flip (similar to a transverse magnetic field) are taken into account within the dot. We find that the interplay between Coulomb interaction and spin accumulation in the dot can result in a bias-dependent current polarization p. In particular, p can be suppressed in the P alignment and enhanced in the AP case depending on the bias voltage. The coherent spin flip can also result in a switch of the current polarization from the emitter to the collector lead. Interestingly, for a particular set of parameters it is possible to have a polarized current in the collector and an unpolarized current in the emitter lead. We also found a suppression of the Fano factor to values well below 0.5.

Building a Open Source Framework for Virtual Medical Training

This paper presents a framework to build medical training applications by using virtual reality and a tool that helps the class instantiation of this framework. The main purpose is to make easier the building of virtual reality applications in the medical training area, considering systems to simulate biopsy exams and make available deformation, collision detection, and stereoscopy functionalities. The instantiation of the classes allows quick implementation of the tools for such a purpose, thus reducing errors and offering low cost due to the use of open source tools. Using the instantiation tool, the process of building applications is fast and easy. Therefore, computer programmers can obtain an initial application and adapt it to their needs. This tool allows the user to include, delete, and edit parameters in the functionalities chosen as well as storing these parameters for future use. In order to verify the efficiency of the framework, some case studies are presented.

Process oriented framework to support PLM implementation

Product lifecycle management (PLM) innovates as it defines both the product as a central element to aggregate enterprise information and the lifecycle as a new time dimension for information integration and analysis. Because of its potential benefits to shorten innovation lead-times and to reduce costs, PLM has attracted a lot of attention at industry and at research. However, the current PLM implementation stage at most organisations still does not apply the lifecycle management concepts thoroughly. In order to close the existing realisation gap, this article presents a process oriented framework to support effective PLM implementation. The framework central point consists of a set of lifecycle oriented business process reference models which links the necessary fundamental concepts, enterprise knowledge and software solutions to effectively deploy PLM. (c) 2007 Elsevier B.V. All rights reserved.

Thermal inactivation of polyphenoloxidase and peroxidase in green coconut (Cocos nucifera) water

P>Coconut water is an isotonic beverage naturally obtained from the green coconut. After extracted and exposed to air, it is rapidly degraded by enzymes peroxidase (POD) and polyphenoloxidase (PPO). To study the effect of thermal processing on coconut water enzymatic activity, batch process was conducted at three different temperatures, and at eight holding times. The residual activity values suggest the presence of two isoenzymes with different thermal resistances, at least, and a two-component first-order model was considered to model the enzymatic inactivation parameters. The decimal reduction time at 86.9 degrees C (D(86.9 degrees C)) determined were 6.0 s and 11.3 min for PPO heat labile and heat resistant fractions, respectively, with average z-value = 5.6 degrees C (temperature difference required for tenfold change in D). For POD, D(86.9 degrees C) = 8.6 s (z = 3.4 degrees C) for the heat labile fraction was obtained and D(86.9 degrees C) = 26.3 min (z = 6.7 degrees C) for the heat resistant one.

New Analytic Solution Related to the Richards, Philip, and Green-Ampt Equations for Infiltration

Based on physical laws of similarity, an analytic solution of the soil water potential form of the Richards equation was derived for water infiltration into a homogeneous sand. The derivation assumes a similarity between the soil water retention function and that of the soil water content profiles taken at fixed times. The new solution successfully described soil water content profiles experimentally measured for water infiltrating downward, upward, and horizontally into a homogeneous sand and agrees with that presented by Philip in 1957. The utility of this analysis is still to be verified, but it is expected to hold for soils that have a narrow pore-size distribution before wetting and that manifest a sharp increase of water content at the wetting front during infiltration. The effect of van Genuchten`s parameters alpha and n on the application of the solution to other porous media was investigated. The solution also improves and provides a more realistic description of the infiltration process than that pioneered by Green and Ampt in 1911.

Sustainability certification of bioethanol: how is it perceived by Brazilian stakeholders?

This paper investigates whether initiatives for sustainability certification of Brazilian ethanol can be expected to stimulate a change among producers toward more sustainable production - and, if so, what those changes would likely be. Connected to this, several questions are raised including whether producers might prefer to target other markets with less stringent demands, and if certification might lead to structural changes in the sector because producers who lack the capacity to meet the new requirements cannot remain competitive. The analysis of interviews with a diverse group of stakeholders under the guidance of the Technological Innovation Systems framework allowed us identify different actions taken by the Brazilian sugarcane ethanol sector in response to requirements of sustainability. The interviewees agreed that sustainability certification is an important element for the expansion of biofuel production in Brazil. Brazilian stakeholders have created a platform for more competitive sustainable production and have initiated relevant processes in response to the development connected to sustainability certification. Yet, the certification activities have had a limited impact in terms of the number of involved stakeholders. But interview responses indicate that the sector may adapt to new certification requirements rather than leave markets where such requirements become established. Structural changes can be expected if certification requirements as they exist in many initiatives are introduced in unflexible ways. The social importance of the ethanol industry is large in Brazil and some adjustments for certification may be required. The paper concludes by suggesting some actions for the industry. (C) 2010 Society of Chemical Industry and John Wiley & Sons, Ltd

Thermal properties and resistant starch content of green banana flour (Musa cavendishii) produced at different drying conditions

The objective of this research was to verify the effect of drying conditions on thermal properties and resistant starch content of green banana flour (Musa cavendishii). The green banana flour is a complex-carbohydrates source, mainly of resistant starch, and quantifying its gelatinization is important to understand how it affects food processing and the functional properties of the flour. The green banana flour was obtained by drying unripe peeled bananas (first stage of ripening) in a dryer tunnel at 52 degrees C, 55 degrees C and 58 degrees C and air velocity at 0.6 m s(-1), 1.0 m s(-1) and 1.4 m s(-1). The results obtained from differential scanning calorimetry, (DSC) curves show a single endothermic transition and a flow of maximum heating at peak temperatures from (67.95 +/- 0.31)degrees C to (68.63 +/- 0.28) degrees C. ANOVA shows that only drying temperature influenced significantly (P < 0.05) the gelatinization peak temperature (Tp). Gelatinization enthalpy (Delta H) varied from 9.04 J g(-1) to 11.63 J g(-1) and no significant difference was observed for either temperature or air velocity. The resistant starch content of the flour produced varied from (40.9 +/- 0.4) g/100 g to (58.5 +/- 5.4) g/100 g, on dry basis (d. b.), and was influenced by the combination of drying conditions: flour produced at 55 degrees C/1.4 m s(-1) and 55 degrees C/1.0 m s(-1) presented higher content of resistant starch. (c) 2009 Elsevier Ltd. All rights reserved

Citrate and Phosphate Influence on Green Fluorescent Protein Thermal Stability

Protein structure and function can be regulated by no specific interactions, such as ionic interactions in the presence of salts. Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. The aim of this study was to evaluate the thermal stability of GFP in the presence of different salts at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were higher in the presence of citrate and phosphate, when compared with that obtained in their absence, indicating that these salts stabilized the protein against thermal denaturation. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 27: 269-272, 2011

Effect of Polyethylene Glycol on the Thermal Stability of Green Fluorescent Protein

Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. Some polymers, such as polyethylene glycol, are often used as modifiers of characteristics of biological macromolecules, to improve the biochemical activity and stability of proteins or drug bioavailability. The aim of this study was to evaluate the thermal stability of GFP in the presence of different PEG molar weights at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were almost constant for temperatures of 85, 90, and 95 degrees C, despite the PEG concentration or molar weight studied. Even though PEG can stabilize proteins, only at 75 degrees C, PEG 600 and 4,000 g/mol stabilized GFP. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 26: 252-256, 2010

Sterilization of Medical Devices by Ethylene Oxide, Determination of the Dissipation of Residues, and Use of Green Fluorescent Protein as an Indicator of Process Control

Ethylene oxide (EO) is used to sterilize Oxygenator and Tubing applied to heart surgery. Residual levels of EO and its derivatives, ethylene chlorohydrin (ECH) and ethylene glycol (EG), may be hazardous to the patients. Therefore, it must be removed by the aeration process. This study aimed to estimate the minimum aeration time for these devices to attain safe limits for use (avoiding excessive aeration time) and to evaluate the Green Fluorescent Protein (GFP) as a biosensor capable of best indicating the distribution and penetration of EO gas throughout the sterilization chamber. Sterilization cycles of 2, 4, and 8 h were monitored by Bacillus atrophaeus ATCC 9372 as a biological indicator (131) and by the GFP. Residual levels of EO, ECH, and EG were determined by gas chromatography (GC), and the residual dissipation was studied. Safe limits were reached right after the sterilization process for Oxygenator and after 204 h of aeration for Tubing. In the 2 h cycle, the GFP concentration decreased from 4.8 (+/- 3.2)% to 7.5 (+/- 2.5)%. For the 4 h cycle, the GFP concentration decreased from 17.4 (+/- 3.0)% to 21.5 (+/- 6.8)%, and in the 8 h cycle, it decreased from 22.5 (+/- 3.2)% to 23.9 (+/- 3.9)%. This finding showed the potentiality for GFP applications as an EO biosensor. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9113: 626-630, 2009

Separation and partitioning of Green Fluorescent Protein from Escherichia coli homogenate in poly(ethylene glycol)/sodium-poly(acrylate) aqueous two-phase systems

The partitioning of Green Fluorescent Protein (GFP) in poly(ethylene glycol)/Na-poly(acrylate) aqueous two-phase systems (PEG/NaPA-ATPS) has been investigated. The aqueous two-phase systems are formed by mixing the polymers with a salt and a protein solution. The protein partitioning in the two-phase system was investigated at 25 degrees C. The concentration of the GFP was measured by fluorimetry. It was found that the partitioning of GFP depends on the salt type, pH and concentration of PEG. The data indicates that GFP partitions more strongly to the PEG phase in presence of Na2SO4 relative to NaCl. Furthermore, the GFP partitions more to the PEG phase at higher pH. The partition to the PEG phase is strongly favoured in systems with larger tie-line lengths (i.e. systems with higher polymer concentrations). The molecular weight of PEG is important since the partition coefficient (K) of GFP gradually decreases with increasing PEG size, from K ca. 300-400 for PEG 400 to K equal to 1.19 for PEG 8000. A separation process was developed where GFP was separated from a homogenate in two extraction steps: the GFP is first partitioned to the PEG phase in a PEG 3000/NaPA 8000 system containing 3 wt% Na2SO4, where the K value of GFP was 8. The GFP is then re-extracted to a salt phase formed by mixing the previous top-phase with a Na2SO4 solution. The K-value of GFP in this back-extraction was 0.22. The total recovery based on the start material was 74%. (c) 2008 Elsevier B.V. All rights reserved.

Investigation of charged polymer influence on green fluorescent protein thermal stability

Methods of stabilization and formulation of proteins are important in both biopharmaceutical and biocatalysis industries. Polymers are often used as modifiers of characteristics of biological macromolecules to improve the biochemical activity and stability of proteins or drug bioavailability. Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. Relative thermal stability was undertaken by incubation of GFP at varying temperatures and GFP fluorescence was used as a reporter for unfolding. At 80 degrees C, DEAE-dextran did not have any effect on GFP fluorescence, indicating that it does not confer stability.

Biomonitoring of biosurfactant production by green fluorescent protein-marked Bacillus subtilis W1012

BACKGROUND: Biosurfactant production was investigated using two strains of Bacillus subtilis, one being a reference strain (B. subtilis 1012) and the other a recombinant of this (B. subtilis W1012) made able to produce the green fluorescent protein (GFP). RESULTS: Batch cultivations carried out at different initial levels of glucose (GO) in the presence of 10 g L(-1) casein demonstrated that the reference strain was able to release higher levels of biosurfactants in the medium at 5.0 <= G(0) <= 10 g L(-1) (B(max) = 104-110 mg L(-1)). The recombinant strain exhibited slightly lower levels of biosurfactants(B(max) = 90-104 mg L(-1))but only at higher glucose concentrations (G(0) >= 20 g L(-1)). Under these nutritional conditions, the fluorescence intensity linked to the production of GFP was shown to be associated with the cell concentration even after achievement of the stationary phase. CONCLUSION: The ability of the genetically-modified strain to simultaneously overproduce biosurfactant and GFP even at low biomass concentration makes it an interesting candidate for use as a biological indicator to monitor indirectly the biosurfactant production in bioremediation treatments. (C) 2008 Society of Chemical Industry