Immobilization of α‐amylase in polyelectrolyte complexes

Herein, we report the formation of α‐amylase containing polyelectrolyte complexes (PECs). The method for the encapsulation of α‐amylase is based on interactions between two oppositely charged polyelectrolytes, poly(acrylic acid) (PAA) and polyethylenimine (PEI). We could show that electrostatic interactions ensure the incorporation of the enzyme into the formed polyelectrolyte complexes. The encapsulation has no negative effect on enzyme activity and protects against denaturation of the enzyme initiated by low pH values. The resulting PECs are 150–250 nm in size with narrow size distribution, appear in a spherical shape and are colloidally stable. The complexation of both polyelectrolytes and the immobilization of α‐amylase are investigated using fractionating techniques mainly the analytical ultracentrifugation and asymmetrical‐flow field‐flow fractionation. The formation of PECs represents a simple method for the encapsulation of α‐amylase without the use of organic solvents and requires no additional purifications steps. This one‐step approach, yielding high encapsulation efficiencies, shows the potential as a drug delivery system for sensitive hydrophilic actives in future. α‐amylase is immobilized in polyelectrolyte complexes made of polyethylenimine and poly(acrylic acid). Optimized encapsulation conditions and the resulting polyelectrolyte complexes are investigated via determination of IEP, α‐amylase activity assays, nanoDSC measurements, zeta potential values, dynamic light scattering, microscopy, and fractionating techniques. The encapsulated enzyme is protected against denaturation initiated by low pH values. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45036.     

Dietary Fatty‐Acid Compositions Are more Strongly Reflected in Fatty than Lean Dorsal Fillets of Common Carp (Cyprinus carpio L.)

In this fish‐feeding study, we tested similarity patterns between fatty acids (FA) in diets and common carp (Cyprinus carpio) of fish ponds used for semi‐intensive aquaculture, containing naturally occurring pond zooplankton and different feeds (marine or terrestrial feeds) until carp reached market size. We evaluated if and how total lipid contents in dorsal fillets can reflect dietary FA compositions in farm‐raised common carp and hypothesized that increasing total lipid contents in dorsal fillets significantly increase the similarity between dietary and dorsal fillets’ FA compositions. Results of this study showed that carps had higher total lipids when supplied with marine feeds and dietary FA compositions were indeed more strongly reflected in fatty (i.e. high total lipid contents) than in leaner dorsal fillets (low total lipid contents). Increasing total lipid contents in dorsal fillets significantly increased the similarity between the dietary and dorsal fillets’ FA compositions. In contrast, leaner dorsal fillets had FA patterns that were more distinct from dietary FA. Total lipid contents higher than ~60 mg/g dry weight in dorsal fillets had only limited effects on increasing the similarity between FA compositions of diets and dorsal fillets, and were independent of feed sources. It is thus suggested that higher total lipid contents in dorsal fillets can be used as a proxy to predict dietary FA profiles in common carps, or perhaps even in farm‐raised fish in general.     

The use of carbon nanomaterials in membrane distillation membranes: a review

Membrane distillation (MD) is a thermal-based separation technique with the potential to treat a wide range of water types for various applications and industries. Certain challenges remain however, which prevent it from becoming commercially widespread including moderate permeate flux, decline in separation performance over time due to pore wetting and high thermal energy requirements. Nevertheless, its attractive characteristics such as high rejection (ca. 100%) of non-volatile species, its ability to treat highly saline solutions under low operating pressures (typically atmospheric) as well as its ability to operate at low temperatures, enabling waste-heat integration, continue to drive research interests globally. Of particular interest is the class of carbon-based nanomaterials which includes graphene and carbon nanotubes, whose wide range of properties have been exploited in an attempt to overcome the technical challenges that MD faces. These low dimensional materials exhibit properties such as high specific surface area, high strength, tuneable hydrophobicity, enhanced vapour transport, high thermal and electrical conductivity and others. Their use in MD has resulted in improved membrane performance characteristics like increased permeability and reduced fouling propensity. They have also enabled novel membrane capabilities such as in-situ fouling detection and localised heat generation. In this review we provide a brief introduction to MD and describe key membrane characteristics and fabrication methods. We then give an account of the various uses of carbon nanomaterials for MD applications, focussing on polymeric membrane systems. Future research directions based on the findings are also suggested.     

面向城市设计的环境实景感知实证研究

随着人们对生活期望的提高,城市设计开始越来越注重空间环境如何提升城市生活的质量和健康。神经科学和计算机图形学等技术的发展让我们能够更好的描述和测量物理环境对人情绪、认知等心智健康的影响,也能够更好的控制模拟环境刺激。文章简要总结了近两年来课题组在环境感知测量及设计决策支持方面的研究进展,主要包括基于脑电和脑网络分析的环境认知能力影响、基于自主神经反馈的环境情感地图分析和情绪测量,以及基于激光扫描的虚拟环境构建等方面。     

Biodiesel Production by Enzymatic Catalysis Process Using Two Analytical Ways： Gas Chromatography and Total Glycerol Determination

Currently, biodiesel is presented as one of the best alternatives for gradually replacing the use of fossil fuels, but it has some factors that make it economically impractical if it does not have a government support. For this reason, research efforts focused on this area have been responsible for optimizing the process of biodiesel production by different catalytic routes to achieve greater efficiency at a lower cost. In this case, the biggest problem has been the high cost generated by an investigation, which in many occasions is the main factor to decide if an investigation could be carried out. Trying to reduce these costs, in the current study, we are using a technique of glycerol quantification by volumetric methods and comparing obtained results with the chromatographic method, which is conventionally used and comparatively much more expensive. Biodiesel employee was obtained by an enzymatic catalysis process varying one of three process variables：oil：alcohol molar ratio, temperature and proportion of catalyst. The numerical differences obtained between the two quantification methods generated relative errors lower than 10%, resulting in some occasions lower than 1%. By gas chromatography analysis the best yield was obtained at the same conditions of the volumetric method, a temperature of 45 ℃, an oil：alcohol ratio 1：4 and 8 wt.% of catalyst, but a yield of 95.5% and 97.1%, respectively. Due to the high precision of gas chromatography, this method is used to carry out a surface response analysis obtaining as ideal operating conditions a temperature of 43.5 ℃, 8.9 wt.%. of catalyst and an oil：alcohol ratio 1：4.     

Nanomedicine-Based Delivery Strategies for Breast Cancer Treatment and Management

Breast cancer is one of the most common types of cancer among women globally. It is caused by mutations in the estrogen/progesterone receptors and conventional treatment methods are commonly utilized. About 70–80 percent of individuals with the early-stage non-metastatic disease may be cured. Conventional treatment is far less than the optimal ratio, as demonstrated through the high mortality rate of women with this cancer. However, conventional treatment methods like surgery, radiotherapy, and chemotherapy are not as effective as expected and lead to concerns about low bioavailability, low cellular uptake, emerging resistance, and adverse toxicities. A nanomedicine-based approach is a promising alternative for breast cancer treatment. The present era is witnessing rapid advancements in nanomedicine as a platform for investigating novel therapeutic applications and modern intelligent healthcare management strategies. This paper focuses on nanomedicine-based therapeutic interventions that are becoming more widely accepted for improving treatment effectiveness and reducing undesired side effects in breast cancer patients. By evaluating the state-of-the-art tools and taking the challenges involved into consideration, various aspects of the proposed nano-enabled therapeutic approaches have been discussed in this review.     

Molecular Cross-Talk between Gravity- and Light-Sensing Mechanisms in Euglena gracilis

Euglena gracilis is a photosynthetic flagellate. To acquire a suitable position in its surrounding aquatic environment, it exploits light and gravity primarily as environmental cues. Several physiological studies have indicated a fine-tuned relationship between gravity sensing (gravitaxis) and light sensing in E. gracilis. However, the underlying molecular mechanism is largely unknown. The photoreceptor photoactivated adenylyl cyclase (PAC) has been studied for over a decade. Nevertheless, no direct/indirect interaction partner (upstream/downstream) has been reported for PAC. It has been shown that a specific protein, kinase A (PKA), showed to be involved in phototaxis and gravitaxis. The current study reports the localization of the specific PKA and its relationship with PAC.     

Gas–Solid Interactions During Nonisothermal Heat Treatment of a High-Strength CrMnCN Austenitic Steel Powder: Influence of Atmospheric Conditions and Heating Rate on the Densification Behavior

This work deals with gas?Csolid interactions between a high-alloyed steel powder and the surrounding atmosphere during continuous heating. It is motivated by the recently developed corrosion-resistant CrMnCN austenitic cast steels. Here, powder metallurgical processing would be desirable to manufacture highly homogeneous parts and/or novel corrosion-resistant metal-matrix composites. However, the successful use of this new production route calls for a comprehensive investigation of interactions between the sintering atmosphere and the metallic powder to prevent undesirable changes to the chemical composition, e.g., degassing of nitrogen or evaporation of manganese. In this study, dilatometric measurements combined with residual gas analysis, high-temperature X-ray diffraction (XRD) measurements, and thermodynamic equilibrium calculations provided detailed information about the influence of different atmospheric conditions on the microstructure, constitution, and densification behavior of a gas-atomized CrMnCN steel powder during continuous heating. Intensive desorption of nitrogen led to the conclusion that a vacuum atmosphere is not suitable for powder metallurgical (PM) processing. Exposure to an N₂-containing atmosphere resulted in the formation of nitrides and lattice expansion. Experimental findings have shown that the N content can be controlled by the nitrogen partial pressure. Furthermore, the reduction of surface oxides because of a carbothermal reaction at elevated temperatures and the resulting enhancement of the powder??s densification behavior are discussed in this work.