Nano-encapsulation of protein using an enteric polymer as carrier

In this preliminary work, an enteric polymer has been used for encapsulating bovine serum albumine (BSA) as a model protein drug. Poly (lactide-co- glycolide) has been commonly used for oral administration purposes as a polymer matrix, but in this case an enteric polymer was used effectively to protect the protein in a gastric environment. A modified water/oil/water technique was used to decrease the particle diameter, and transmission electron microscopy experiments showed that the average diameter of the nanoparticles obtained was below 100 nm. The spherical nature of the particles and their diameters strongly depend on the control of the process parameters. The encapsulation efficiency was 77% for sample B4, and protein release profiles for both samples B3 and B4 indicate that these systems possess controlled-release characteristics. Finally, as a result of electrophoresis (SDS-PAGE), the BSA was not chemically affected under encapsulation conditions.     

Comprehensive energy and economic transient analysis of an off-grid hydrogen car-integrated zero energy building

Clean Technologies and Environmental Policy - In this study, for the first time, an off-grid zero-energy building with hydrogen energy storage integrated with two hydrogen cars is simulated and...     

Performance of carbon arc-discharge nanotubes to hydrogen energy storage

Adsorption properties of gram-scale samples of different kind of arc discharge nanotubes were studied, namely: (A) raw collaret collected on the cathode, (B) raw soots collected on the lateral reactor wall, (C) thermally treated soot, and (D) thermally then chemically treated soot. The morphology, structure, and composition of these materials were characterized by SEM, TEM, TGA, and BET. In addition, hydrogen adsorption isotherms were recorded experimentally for A, B, and D samples over the pressure range of 0 to 55 bar at ambient temperature. Our experiments indicated a maximum-yet weak-hydrogen storage at room temperature of approximately 0.13 H2 wt% for the purified product (D).     

Experimental study of temperature sensor for an ocean-going liquid hydrogen (LH2) carrier

The prototype temperature sensors for an ocean-going liquid hydrogen (LH₂) carrier were manufactured by way of trial. All of the sensors adopted Platinum 1000 (PT-1000) resistance thermometer elements. Various configurations of preproduction temperature sensors were tested in AIST’s LH₂ test facility. In the experiments, a PT-1000 resistance thermometer, calibrated at the National Metrology Institute of Japan at AIST, was used as the standard thermometer. The temperatures measured by the preproduction sensors were compared with the temperatures measured by the standard thermometer, and the measurement accuracy of the temperature sensors in LH₂ was investigated and discussed. It was confirmed that the measurement accuracies of the preproduction temperature sensors were within ±50 mK, which is the required measurement accuracy for a technical demonstration ocean-going LH₂ carrier.     

Photosynthesis of hydrogen and methane as key components for clean energy system

While researchers are trying to solve the world’s energy woes, hydrogen is becoming the key component in sustainable energy systems. Hydrogen could be produced through photocatalytic water-splitting technology. It has also been found that hydrogen and methane could be produced through photocatalytic reduction of carbon dioxide with water. In this exploratory study, instead of coating catalysts on a substrate, pellet form of catalyst, which has better adsorption capacity, was used in the photo-reduction of carbon dioxide with water. In the experiment, some water was first absorbed into titanium dioxide pellets. Highly purified carbon dioxide gas was then discharged into a reactor containing these wet pellets, which were then illuminated continuously using UVC lamps. Gaseous samples accumulated in the reactor were extracted at different intervals to analyze the product yields. The results confirmed that methane and hydrogen were photosynthesized using pellet form of TiO₂ catalysts. Hydrogen was formed at a rate as high as 0.16 micromoles per hourμmol h^–1). The maximum formation rate of CH₄ was achieved at 0.25 μmol h^–1 after 24 h of irradiation. CO was also detected.     

Plasmonic energy collection through hot carrier extraction

Conversion of light into direct current is important for applications ranging from energy conversion to photodetection, yet often challenging over broad photon frequencies. Here we show a new architecture based on surface plasmon excitation within a metal-insulator-metal device that produces power based on spatial confinement of electron excitation through plasmon absorption. Plasmons excited in the upper metal are absorbed, creating a high concentration of hot electrons which can inject above or tunnel through the thin insulating barrier, producing current. The theoretical power conversion efficiency enhancement achieved can be almost 40 times larger than that of direct illumination while utilizing a broad spectrum of IR to visible wavelengths. Here we present both theoretical estimates of the power conversion efficiency and experimental device measurements, which show clear rectification and power conversion behavior.     

PEG-grafted chitosan nanoparticles as an injectable carrier for sustained protein release

The development of injectable nanoparticulate “stealth” carriers for protein delivery is a major challenge. The objective of this work was to investigate the possibility of achieving the controlled release of a model protein, insulin, from PEG-grafted chitosan (PEG-g-chitosan) nanoparticles (mean diameter 150–300 nm) prepared by the ion gelation method. Insulin was efficiently incorporated into the nanoparticles, and reached as high as 38%. In vitro release showed that it could control the insulin release by choosing the composition, loading and release temperature. We observed that the composition of the nanoparticle surface (C/O ratio) increased from 2.40 to 3.23, with an increase in the incubation time. Therefore, we concluded that during this time, insulin release from PEG-g-chitosan nanoparticles followed a diffusion mechanism in which erosion was negligible. The experiments also demonstrated that PEG-g-chitosan helped to maintain the natural structure of the protein entrapped in the nanoparticles.     

Use of an osteoinductive biomaterial as a bone morphogenetic protein carrier

A porous calcium phosphate ceramic, which induced bone formation in soft tissues of dogs, was termed as osteoinductive biomaterial and studied as a carrier of bone morphogenetic protein (rhBMP-2). Cylinder implants (ø 4×5 mm) impregnated with 0, 1, 10 and 40 g rhBMP-2 were implanted in dorsal muscles of rabbits for five weeks. Histological observation and histomorphometric analysis were performed on thin un-decalcified sections. No bone formation was detected in the implants without rhBMP-2, while mature lamellar bone was found inside the implants with 1 g rhBMP-2, both on the outer surface and inside the implants with 10 g and 40 g rhBMP-2. Little difference in formed bone was found between 1 g and 10 g rhBMP-2, but no difference was found between 10 g and 40 g rhBMP-2. A significant difference in bone marrow formation was found among 1, 10 and 40 g rhBMP-2. The more rhBMP-2, the more bone marrow formed. The present results indicate that osteoinductive biomaterial is a good carrier of BMP and high dose of BMP is not necessary for bone formation in clinic. © 2001 Kluwer Academic Publishers     

Phospholipid-Tween 80 mixed micelles as an intravenous delivery carrier for paclitaxel

A novel mixed micelle made of Tween 80 and soybean phospholipids (S80) was prepared and used as the delivery system for paclitaxel (PTX), with the purpose of improving the stability, therapeutic index, and security of PTX in comparison with Taxol? injection. The micelle size, morphological features, dilution stability, and critical micelle concentration (CMC) were measured. The in vitro antitumor activity, pharmacokinetics, and hemolysis effect of the optimal PTX-loaded mixed micelles (PTX-M) were evaluated and compared with Taxol?. The results showed that PTX-M was more stable than Taxol? upon dilution. PTX-M had a higher antitumor efficacy against HeLa and A549 cells than that of Taxol?. The plasma AUC of PTX-M was 1.3-fold higher than that of Taxol? and the hemolysis test revealed that PTX-M was safe for intravenous injection. In conclusion, PTX-M had a higher dilution stability and antitumor efficacy than Taxol?, but significantly reduced the toxicity while improving the bioavailability of PTX. Therefore, Tween 80-S80 mixed micelles could be a promising drug carrier for intravenous administration of PTX.     

SPION nanoparticles as an efficient probe and carrier of DNA to umbilical cord blood-derived mesenchymal stem cells

Superparamagnetic iron oxide nanoparticles (SPION) were used to transfer gene into umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) in this study. This novel transfection method using SPION is safe and effective to UCB-MSCs, and would be a tool for genetic optimization with a significant potential for cell tracing.     

Prospects of the application of hydrogen as an alloying element

Data presented in metal-hydrogen phase diagrams are summarized for metals that normally do not form hydrides. At high temperatures, all systems of this sort are characterized by a gas-eutectic equilibrium. The gas-cutectic transformation is analyzed in detail. It is shown that this transformation generates various gas-solid structures. Porous materials produced as a result of gas-eutectic reactions have numerous advantages over traditional materials. We call this family of new porous materials gasars.State Metallurgical Academy of the Ukraine, Dnepropetrovsk. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 30, No. 4, pp. 24–30, July – August, 1994.     

Application of an energy balance and an energy method to dynamic crack propagation

The speeds of fast running cracks in a range of quasi-brittle materials are measured as a function of the dynamic strain energy release rate. From the results, the heat output associated with the plastic work at the crack tip is calculated as a function of crack speed using an energy balance, and compared with the heat outputs determined experimentally using an energy method. A generally good agreement is found between the calculated and the experimentally measured variation of heat output with crack speed.

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Zusammenfassung Die Geschwindigkeiten schnell-laufender Brüche werden als Funktion der dynamischen Energiefreisetzungsrate für eine Anzahl unterschiedlich spröder Materialien gemessen. Aus diesen Ergebnissen wird mit Hilfe einer Energiebilanz die durch die plastischen Deformationen an der Rißspitze entstehende Wärme berechnet und mit der durch eine Energiemethode experimentell gemessenen Wärme verglichen. Es wird eine im allgemeinen gute Übereinstimmung zwischen dem berechneten und gemessenen Verlauf der Wärme als Funktion der Bruchgeschwindigkeit gefunden.

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Résumé Les vitesses de propagation des fissures en développement rapide dans une gamme de matériaux quasi-fragile sont mesurés en fonction de la vitesse de relaxation de l'énergie de déformation dynamique. A partir des résultats obtenus, on calcule la dissipation de chaleur associée au travail de formation plastique à l'extrémité de la fissure en fonction de la vitesse de la fissure correspondant à un équilibre énergétique. On compare ces valeurs calculées avec les dissipations de chaleur déterminées expérimentalement à l'aide d'une méthode énergétique. En général, on trouve un bon accord entre les variations de dissipation de chaleur calculées et mesurées par voie expérimentale en fonction de la vitesse de fissuration.

     

COVID-19 in the Twitterverse,from epidemic to pandemic: information-sharing behavior and Twitter as an information carrier

Scientometrics - In this study, we defined a Twitter network as an information channel that includes information sources containing embedded messages. We conducted stage-based comparative analyses...     

Transverse tunneling through DNA hydrogen bonded to an electrode

Guanidinium ions tethered to an electrode form electrical contacts to DNA via hydrogen bonding with the backbone phosphates, thus providing a sequence-independent electrical connector for native DNA submerged in an aqueous electrolyte. DNA adlayers on a guanidinium modified electrode can be imaged by scanning tunneling microscopy with tens of pS gap conductance. The image resolution suggests that multiatom contacts contribute to the tunnel conductance, so we estimate that the single-nucleotide pair conductance may be on the order of 1 pS.     

海藻酸钠作为药物载体材料的研究进展

综述海藻酸钠作为药物载体材料的研究进展;依据国内外的文献报道来阐述海藻酸盐凝胶材料、海藻酸钠共混材料、海藻酸钠化学改性材料作为药物载体材料的研究进展;海藻酸钠作为药物载体材料有很广阔的应用前景.     

Using biomass as an energy source with low CO2 emissions

This work deals with the carbon dioxide cycle and emissions from biomass incineration under a hydrogen production context. It is proposed to use the thermal energy obtained by biomass combustion to produce water steam, which afterwards would be converted into hydrogen by high temperature electrolysis (HTE). In France, the thermal energy potential from nonvalorised biomass reaches almost 6.5 Mtep. In this study, the potential avoided carbon emissions are quantified as well as the feasible hydrogen production capacity based on the steam supplied by the incineration units. Results show that carbon consumption in hydrogen production by steam methane reforming (SMR) or biomass incineration–HTE process is almost equivalent between both processes. However, the hydrogen produced by the biomass incineration–HTE process used to fuel vehicles, would lead to a decrease of 135 Mt of carbon from fossil origins yearly, in contrast to SMR.     

PVA:Nano-eggshell microcomposite as an energy storage material for supercapacitors

Journal of Materials Science: Materials in Electronics - The development and advantages of wearable flexible electronics have become attractive issues with excellent electrochemical performances in...