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Abstract Axonal growth cones mediate axonal guidance and growth regulation. We show that migrating neurons in mice possess a growth cone at the tip of their leading process, similar to that of axons, in terms of the cytoskeletal dynamics and functional responsivity through protein tyrosine phosphatase receptor type sigma (PTPσ). Migrating-neuron growth cones respond to chondroitin sulfate (CS) through PTPσ and collapse, which leads to inhibition of neuronal migration. In the presence of CS, the growth cones can revert to their extended morphology when their leading filopodia interact with heparan sulfate (HS), thus re-enabling neuronal migration. Implantation of an HS-containing biomaterial in the CS-rich injured cortex promotes the extension of the growth cone and improve the migration and regeneration of neurons, thereby enabling functional recovery. Thus, the growth cone of migrating neurons is responsive to extracellular environments and acts as a primary regulator of neuronal migration.

In the temperature programmed desorption-mass spectrometry (TPD-MS) experiments, the time lag and broadening of the gas evolved from the sample until it is detected by the MS detector can be a problem. The deconvolution method was successfully applied to TPD-MS. The pulse injection of N2, 1-butene, CO2, and H2O gasses in the TPD-MS system showed the same MS intensity-time response. This result suggests the MS signal can be used as an impulse response function of deconvolution analysis. The present TPD-MS method was applied to evaluate the dehydration from zeolites during heating. The shape of differential thermogravimetry (DTG) curves was in good agreement with deconvolved TPD-MS curves. The signal-to-noise ratio of TPD-MS is higher than that of DTG. The present method can be applicable for TG-MS or Fast scanning calorimetry (FSC)-MS in the upcoming study.

Fast scanning calorimetry (FSC) enables rapid sample cooling from the melt at rates of several thousand Kelvin per second. A perfect amorphous state for polypropylene (PP) can be achieved by fast cooling at rates of 5000 K s-1. In comparison, polyethylene (PE) crystallizes during cooling, even at cooling rates accessible with FSC. Thus, in this study, a novel method was proposed for determining the PP/PE mixing ratio with a standard deviation of 1.4 mass% that combines FSC and differential scanning calorimetry. The proposed method considers the above thermal behavior of the components of polyolefin blends. In addition, the proposed method is expected to provide a convenient way to analyze the composition of recycled polyolefins from the market or industrial processes without the need for high-temperature solvents that are typically used in nuclear magnetic resonance or for calibration curves in Fourier transform infrared spectrophotometry. [ABSTRACT FROM AUTHOR]

Crystallization and melting kinetics of polyphenylene sulfide (PPS) are determined using fast scanning calorimetry. The temperature dependence of half-time crystallization of isothermally melt-crystallized PPS shows a downward convex curve with a minimum at 160 °C. The minimum crystallization half-time is about 3 s. The analysis of heating rate dependence of the melting temperature reveals a zero-entropy-production melting temperature of the sample. The microstructure of the sample, which is prepared by fast scanning calorimetry, is investigated by small-angle X-ray scattering and polarizing optical microscopy. The crystallinity and lamellar thickness of the sample annealed for 400 s decrease with decreasing crystallization temperature. The size of spherulites becomes small as the isothermal temperature is decreased. Transcrystalline morphology is observed near the surface between the sample and nitrogen gas at a crystallization temperature of 120 °C. The thickness of the transcrystalline layer disappears as the isothermal temperature is increased. [ABSTRACT FROM AUTHOR]

The lamellar thickness distribution (LTD) of not-reorganized linear polyethylene was calculated on the basis of the melting point distribution using fast scanning calorimetry (FSC) by applying the following precautions. First, by taking sufficiently small sample mass and thickness, the influence of thermal lag during fast-heating is thought to be negligible. Second, by fast-heating, reorganization and cold crystallization are strongly hindered or even suppressed. Third, the influence of superheating has been accounted for and corrected by deconvolution of the FSC curve using the calculated melting kinetics of single-sized lamellae consisting of folded-chain crystal. Under such precautions, the resulting FSC heating curve reflects the melting point distribution of metastable-but-not-reorganized folded-chain crystals. Finally, the Gibbs-Thomson equation was applied to calculate the LTD from the melting point distribution. The average lamellar thickness calculated was in good agreement with that determined by small-angle X-ray scattering and low-frequency Raman spectroscopy. [ABSTRACT FROM AUTHOR]