Stroboscopic near-field imaging for the analysis of contraction of muscle cells

We have developed a stroboscopic near-field optical microscope for observation of biological specimens and observed glycerinated muscles before and after muscle contraction with the developed system. In the system, the optical field distribution localized near the specimen is recorded as the surface topographic distribution of a photosensitive film surface. Our system is very useful for observing living biological specimens with high resolutions, because it is possible to get stroboscopic image by using a photosensitive film as detecting optical distributions instead of a scanning of probes. We have succeeded in observing inner structures of muscle cells with sub-wavelength resolution and achieved higher contrast than an ordinary optical microscope.     

Evaluation of Free-Fall Particle CT Images Using State Transition Matrix

Spatial particle density distribution images in a pipe cross section have been evaluated by means of state transition matrix, which is a parameter indicating the dominant particle density transition patterns among time series images consisting of CT 2-D space and 1-D time. State transition characterizes the transition patterns for positions in a cross section as monotonous transitions, sudden transitions, and extreme value transitions. In a simulation, the real part of the state transition matrix is negative and the imaginary part is zero in the case of monotonous transition. The real part is positive and the imaginary part is zero in the case of extreme value transition. The imaginary part is nonzero in the case of sudden transition. In free-fall particles in a vertical pipe, high, sudden, and extreme value transitions do not occur because the particle flow rate at this position is low, and therefore the probability of collision among particles is also low. High, sudden, and extreme value transitions occur near the pipe center when the particle flow rate is high, because the probability of collision among particles is high.     

铜合金疲劳过程中塑性应变幅的变化

采用自制的平面弯曲疲劳试验装置，进行振动频率为60Hz，应力幅值恒定，平均应力为零的疲劳试验，得到C1100P-1／4H纯铜和C2801P—1／4H黄铜疲劳过程中塑性应变幅与循环次数的关系。利用位错增殖和湮灭机制，推导出试验合金材料疲劳过程中的塑性应变幅的变化仅由可动位错密度和伯格斯矢量决定，而可动位错密度可被描述成疲劳循环数的函数，从而建立起了平面弯曲疲劳过程中塑性应变幅与循环次数的理论关系模型。利用该理论关系模型，对实验结果进行了回归分析，回归结果与实验吻合很好，表明该理论关系模型可用以预测材料的疲劳寿命。     

A COMBINATION OF GLUTAMINASE AND pH CONTROL PREVENTS THE NONENZYMATIC CONVERSION OF l-GLUTAMINE INTO l-2-PYRROLIDINE-5-CARBOXYLIC ACID IN FOOD PROCESSING

A strategy using Alicyclobacillus F‐62 glutaminase was established to minimize the nonenzymatic production of l ‐2‐pyrrolidine‐5‐carboxylic acid (l ‐pyroglutamic acid, savorless amino acid) and maximize the enzymatic production of l ‐glutamic acid (savorous [umami] amino acid) from l ‐glutamine in food‐protein processing. The nonenzymatic production rate of l ‐pyroglutamic acid was influenced by pH and temperature, and decreased over a pH range of 4–6 at 30C. Under optimum conditions (30C and pH 5.0), the l ‐glutamic and l ‐pyroglutamic acids obtained from 1 mM l ‐glutamine in the presence of glutaminase from Alicyclobacillus F‐62 were 0.96 and 0.03 mM, respectively. This novel method is useful for the efficient production of l ‐glutamic acid during food‐protein processing.     

Independent trafficking of flavocytochrome b558 and myeloperoxidase to phagosomes during phagocytosis visualised by energy‐filtering and energy‐dispersive spectroscopy‐scanning transmission electron microscopy

When polymorphonuclear leukocytes (PMNs) phagocytose opsonised zymosan particles (OPZ), free radicals and reactive oxygen species (ROS) are formed in the phagosomes. ROS production is mediated by NADPH oxidase (Nox), which transfers electrons in converting oxygen to superoxide (O₂^?). Nox‐generated O₂^? is rapidly converted to other ROS. Free radical‐forming secretory vesicles containing the Nox redox center flavocytochrome b558, a membrane protein, and azurophil granules with packaged myeloperoxidase (MPO) have been described. Presuming the probable fusion of these vesicular and granular organelles with phagosomes, the translation process of the enzymes was investigated using energy‐filtering and energy‐dispersive spectroscopy‐scanning transmission electron microscopy. In this work, the primary method for imaging cerium (Ce) ions demonstrated the localisation of H₂O₂ generated by phagocytosing PMNs. The MPO activity of the same PMNs was continuously monitored using 0.1% 3,3′‐diaminobenzidine‐tetrahydrochloride (DAB) and 0.01% H₂O₂. A detailed view of these vesicular and granular structures was created by overlaying each electron micrograph with pseudocolors: blue for Ce and green for nitrogen (N).