Protein-conjugated quantum dots effectively delivered into living cells by a cationic nanogel

Quantum dots (QDs) have attracted attention for their potential as a cell imaging regent. However, the development of effective intracellular delivery system for QDs is needed to apply various cell lines without affecting cellular function. We reported here new QDs delivery system by using cationic nanogel consisting of cholesterol-bearing pullulan modified with an amino group (CHPNH2). The uptake of hybrid nanoparticles into HeLa cells was followed by flow cytometry, and confocal laser scanning fluorescence microscopy. Protein-conjugated QDs were effectively internalized into cells by the nanogel compared with a cationic liposome system. The hybrid nanoparticle was used to stain rabbit mesenchymal stem cells (MSCs) so as to evaluate their effect on cell function. CHPNH2-QD hybrid nanoparticles remained detectable inside MSCs for at least 2 weeks of culture and had little effect on the in vitro chondrogenic ability of MSCs. The hybrid nanoparticles are a promising candidate as a cell tracer in tissue engineering.     

Combustion and Sensitivity Characteristics of Mg/TF Pyrolants

Burning rate characteristics and sensitivity characteristics of energetic mixtures composed of metal particles and oxidizers, the so called ‘pyrolants’, were studied experimentally. The pyrolants tested were made of various particle sizes of magnesium (Mg) and polytetrafluoroethylene (TF). Mg/TF pyrolant produces high combustion flame temperature, so it is used as heat sources and igniter pyrolants. The maximum flame temperature (Tf) is 3271 K at 0.1 MPa, and 3483 K at 1 MPa. These values are obtained when Mg concentration is 30%. When the Mg concentrations are less than 50% the pyrolants are not able to burn stably at one atmosphere. The burning rate increases with increasing the concentration of Mg and decreases with increasing the mean diameter of Mg particles at constant pressure. Explosive energy evaluated with drop hammer test decreased with increasing burning rate, so there is strong relationship between burning rate and explosive energy.     

Role of Boron in Burning Rate Augmentation of AP composite propellants

Effect of the addition of boron particles on the burning rate of solid propellants was examined. The propellants tested in this study consisted of ammonium perchlorate (AP) as an oxidizer and carboxyl terminated polybutadiene as a fuel binder. The propellant burning rate is increased significantly by the addition of a small amount of boron particles. The burning rate augmentation is dependent largely on the size and concentration of the boron particles mixed. Thermochemical experiments revealed that the boron particles react with the decomposed gases of AP on and just above the propellant burning surface. The heat flux transferred back from the gas phase to the burning surface of the propellant increases with increasing the total surface of the boron particles mixed within the unit mass of propellant. The burning rate augmentation is correlated to the heat of reaction generated by the oxidation reaction of boron particles.     

Combustion of Energetic Fuel for Ducted Rockets (I)

Energetic solid fuels composed of modified GAP (glycidyl azide polymer) propellants were formulated in order to obtain optimized combustion characteristics for variable flow ducted rockets. Burning rate in a primary combustor and the combustion efficiency in a secondary combustor were studied and evaluated as a function of the mixture ration of fuel and air. The energetic fuels consisting of – N₃ groups in its chemical structure burned very rapidly even though the combustion temperature was low when compared with conventional solid propellants for rockets. The pressure exponent of the burning rate was optimized to gain wide range of mass generation rate. The combustion gases generated in the primary combustor burned very efficiently in a secondary combustor. The effective specific impulse of the ducted rockets was obtained to be about 780 s.     

Elucidation of mosaic patterns in gravel riverbeds using classifying flow velocity regimes obtained from a planar two-dimensional analysis

Gravel riverbeds in the middle reaches of Japanese rivers are essential habitats for various plants and animals. Disturbance from flooding is necessary for the formation of gravel riverbeds, but human control of rivers, such as dams and channelization, has altered flow and sediment regimes, thereby reducing disturbance. The flooding generates a mosaic pattern characterized by varying frequencies and intensities of disturbance in gravel riverbeds. Understanding the disturbance regimes that form mosaic patterns is important for the conservation of biodiversity in rivers. In this study, we proposed a method to extract mosaic patterns from flow velocity regimes obtained by planar two-dimensional analysis by classifying them with time-series clustering. Based on the distribution of Anaphalis margaritacea var. yedoensis on gravel riverbanks, we compared several past flooding events to identify mosaic patterns that are important for A. margaritacea var. yedoensis. The study site is the Echi River, which flows through Shiga Prefecture in Japan and into Lake Biwa. Using a unmanned aerial vehicle (UAV), orthomosaic images with an average ground resolution of 3.3 mm/pixel were created, and colony polygons of A. margaritacea var. yedoensis were created using image detection and visual correction. Hydraulic analysis was performed using iRIC ver2.3 (Nays2DH ver1.0). Time-series clustering was used to classify the flow velocity regimes for each computed mesh into 30 clusters. The relationship between the clusters of each flooding event and the distribution of A. margaritacea var. yedoensis was evaluated. Mosaic patterns were created by classifying the flow velocity regimes of each computational mesh calculated by planar 2D analysis into clusters using time-series clustering. After analyzing the relationship between each cluster and the area of distribution of A. margaritacea var. yedoensis, the first flooding event was determined to be the mosaic pattern that best explained the distribution of A. margaritacea var. yedoensis. Cluster 1, the “low peak, short duration type,” was considered the growth center of A. margaritacea var. yedoensis. The method used in this study is an innovative approach for obtaining mosaic patterns that quantifies these five elements of the disturbance regime.