Tenascin-R is antiadhesive for activated microglia that induce downregulation of the protein after peripheral nerve injury: a new role in neuronal protection

Microglial activation in response to pathological stimuli is characterized by increased migratory activity and potential cytotoxic action on injured neurons during later stages of neurodegeneration. The initial molecular changes in the CNS favoring neuronofugal migration of microglia remain, however, largely unknown. We report that the extracellular matrix protein tenascin-R (TN-R) present in the intact CNS is antiadhesive for activated microglia, and its downregulation after facial nerve axotomy may account for the loss of motoneuron protection and subsequent neurodegeneration. Studies on the protein expression in the facial and hypoglossal nucleus in rats demonstrate that TN-R is a constituent of the perineuronal net of motoneurons and 7 d after peripheral nerve injury becomes downregulated in the corresponding motor nucleus. This downregulation is reversible under regenerative (nerve suture) conditions and irreversible under degenerative (nerve resection) conditions. In short-term adhesion assays, the unlesioned side of brainstem cryosections from unilaterally operated animals is nonpermissive for activated microglia, and this nonpermissiveness is almost abolished by a monoclonal antibody to TN-R. Microglia-conditioned media and tumor necrosis factor-alpha downregulate TN-R protein and mRNA synthesis by cultured oligodendrocytes, which are one of the sources for TN-R in the brainstem. Our findings suggest a new role for TN-R in neuronal protection against activated microglia and the participation of the latter in perineuronal net destruction, e.g., downregulation of TN-R.     

On the refractive index dispersions of ion-beam-synthesized β-FeSi2 layers

Continuous layers and precipitates of the β-FeSi₂ phase were formed by ion-beam synthesis followed by rapid thermal annealing. Two steps of Fe⁺ ion implantation in Si, at energies of 20 and 60 keV, were performed, using three different doses – 5×10¹⁵, 5×10¹⁶, and 10¹⁷ cm^?2. The infrared spectra were used as a criterion for the formation of the β-FeSi₂ phase. The refractive-index-energy dependences were calculated from the transmittance and reflectance spectra, using the general matrix method. From these dependences, the energy band gap and the energies of the higher-energy transitions in the vicinity of the gap were determined.     

Maltase activity and dough rising ability of baker’s yeasts obtained at different growth conditions during the maturation stage

 The effects of temperature, pH and dissolved oxygen (DO) at the final production stage on the quality of baker’s yeast were studied. It was noted that an increase of temperature above 37 °C worsened dough-rising ability; nevertheless, at the same time, a good value of maltase activity – 26.0 nmol⋅min^-1⋅mg^-1 was found. Dough-rising ability and maltase activity are strongly influenced by pH. The highest maltase activity, 68 nmol⋅min^-1⋅mg^-1, was obtained at pH 6.0, which improves the dough-rising ability to 55 cm³ CO₂. The concentration of DO affects the fermentation activity of the strain Saccharomyces cerevisiae 3: the metabolism became oxido-fermentative at less than 40% DO and maltase activity and dough-rising ability increased up to 43.5 nmol⋅min^-1⋅mg^-1 and 56 cm³, respectively. The results indicate that dough-rising ability and maltase activity increased as the temperature increased, and as the concentration of DO decreased. A direct correlation between maltase activity and dough-rising ability was found. Received: 24 October 1996     

革新称重电子技术使模拟与数字技术一体化

西门子(Simens)股份公司通过SimaticS7控制的SiwarexM称重与定量电子的技术,已为PLC世界用户的更多灵活性方面创建了另一个里程碑。SiwarexM与模拟称重传感器在大多数称重技术应用中,都使用按照所谓的应变计原理(DMS原理)工作的称重传感器,可见具有取决于长度的阻抗,该阻抗在惠斯顿测量电桥的称重传感器内错接并平衡。在加载时,应变计将按其长度上负荷比例产生感应。由此引起的阻抗变化使输出信号的测量值变化。继续处理是以称重电子部分进行的(例如,西门子股份公司的Siwarex)。为了构成总信号,把多只称重传感器并联,接着把测量信号引向Siwarex电子部分数字化。在Si-warexM中,由A/D转换器使524000分度的模拟信号数字化,并随时可供模件称重技术功能使用,比如象定量作业。视以10V-DC供电的称重传感器的额定特性值,最大信号值在10mV与40mV之间。这就是SiwarexM称重传感器的典型应用情况。所以,通过使用足够精度的应变计式称重传感器,就能解决大部分应用。SiwarexM与数字式称重传感器正象已提到的那样,在工业称重技术大多数应用情况下,都使用应变计原理的称重传感器。然而,为了测得力与重量,也可以使用另外一些测量原理,比如象所谓的振弦测量原理。在这类称重传感器     

The Direct Detection Effect in the Hot-Electron Bolometer Mixer Sensitivity Calibration

We investigate an error in the noise temperature measurements of the hot-electron bolometer mixers caused by the so-called "direct detection effect". The effect originates in the changing of the mixer parameters when the mixer is loaded on calibration black body sources at different temperatures (300 and 77 K). A correction factor was obtained from the mixer output power versus the bias current dependence, measured by: 1) the local oscillator (LO) power tuning: 2) mixer heating: and 3) application of an external RF source. Furthermore, the direct detection effect was assessed by elimination of the heterodyne response using a LO frequency, which is far off the mixer RF band. We show that the direct detection effect can be mitigated by using an isolator between the mixer and the IF amplifier     

The development and characterization of polymer microinjection molded gratings

Ruled diffraction gratings were fabricated via injection micromolding and characterized via atomic force and scanning‐electron microscopy. A unique aspect of this study was the utilization of commercially available optical grating as the injection molding tooling. After depositing a reflective aluminum (Al) coating with 150 and 250 nm thickness onto the untreated polymer replicas, diffracted power profiles of the polymer gratings were compared with that of the mold. It was found that both the mold and nozzle temperatures, T_mold and T_noz, respectively, are important parameters influencing the fidelity of replication. Statistical analysis, however, revealed that the cyclic olefin copolymer (COC) replicated well the microtopography of the mold but did not replicate properly (within ～20 nm) the nanotopography formed by the Al grains. Grain size quantification revealed that the Al coating with 150‐nm thickness had smaller grains than that with the 250‐nm coating. Furthermore, testing of delamination of the reflective coatings revealed good adhesion between the COC and Al interface. Lastly, photoelasticity measurements showed stress levels only around the gate of the molded components, suggesting that COCs are excellent materials for optical applications. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

A generalized approach to fuzzy optimization

A new approach to fuzzy optimization based on the generalization of Bellman-Zadeh's (BZ) concept is proposed in this article. It consists of a parametric generalization of intersection of fuzzy sets and a generalized defuzzification method. This approach allows the solving of a fuzzy mathematical programming (FMP) problem without transformation to a crisp one. It takes into account all possible fuzzy decisions and allows the degree of conjunction of criteria and constraints to vary. BZ method can be considered a special case of the approach proposed here. A simple algorithm for noniterative solving FMP problem is proposed whereas well-known Zimmermann's approach uses numerical methods. an illustrative example is presented. © 1994 John Wiley & Sons, Inc.