Development of Thick-foil and Fine-pitch GEMs with a Laser Etching Technique

We have produced thick-foil and fine-pitch gas electron multipliers (GEMs) using a laser etching technique. To improve production yield we have employed a new material, Liquid Crystal Polymer, instead of polyimide as an insulator layer. The effective gain of the thick-foil GEM with a hole pitch of 140 um, a hole diameter of 70 um, and a thickness of 100 um reached a value of 10^4 at an applied voltage of 720 V. The measured effective gain of the thick-foil and fine-pitch GEM (80 um pitch, 40 um diameter, and 100 um thick) was similar to that of the thick-foil GEM. The gain stability was measured for the thick-foil and fine-pitch GEM, showing no significant increase or decrease as a function of elapsed time from applying the high voltage. The gain stability over 3 h of operation was about 0.5%. Gain mapping across the GEM showed a good uniformity with a standard deviation of about 4%. The distribution of hole diameters across the GEM was homogeneous with a standard deviation of about 3%. There was no clear correlation between the gain and hole diameter maps.Comment: 21 pages, 9 figure

The Endocannabinoid 2-Arachidonoylglycerol Produced by Diacylglycerol Lipase α Mediates Retrograde Suppression of Synaptic Transmission

SummaryEndocannabinoids are released from postsynaptic neurons and cause retrograde suppression of synaptic transmission. Anandamide and 2-arachidonoylglycerol (2-AG) are regarded as two major endocannabinoids. To determine to what extent 2-AG contributes to retrograde signaling, we generated and analyzed mutant mice lacking either of the two 2-AG synthesizing enzymes diacylglycerol lipase α (DGLα) and β (DGLβ). We found that endocannabinoid-mediated retrograde synaptic suppression was totally absent in the cerebellum, hippocampus, and striatum of DGLα knockout mice, whereas the retrograde suppression was intact in DGLβ knockout brains. The basal 2-AG content was markedly reduced and stimulus-induced elevation of 2-AG was absent in DGLα knockout brains, whereas the 2-AG content was normal in DGLβ knockout brains. Morphology of the brain and expression of molecules required for 2-AG production other than DGLs were normal in the two knockout mice. We conclude that 2-AG produced by DGLα, but not by DGLβ, mediates retrograde suppression at central synapses

Uptake of Iodine and Bromine by Ion-Exchange Resins in Aqueous Solution

The uptakes of molecular iodine and bromine by both strong acid cation (Dowex 50W-X4 and X8) and strong base anion (Dowex 1-X4 and X8) exchange resins have been studied in aqueous solutions at 25°C. An empirical formula for the amount of solute taken up by the resin in mmol per gram of dry resin, Q, as a function of the solute concentration in M (mol dm-3), C, was derived. Direct proportional relationships between Q and C have been found, except for the　bromine-anion exchanger system. In contrast to the cation-exchange resin, the anion exchanger exhibits extremely high affinity for I2 and Br2

Modification of single-nucleotide polymorphism in a fully humanized CYP3A mouse by genome editing technology

Abe, S., Kobayashi, K., Oji, A. et al. Modification of single-nucleotide polymorphism in a fully humanized CYP3A mouse by genome editing technology. Sci Rep 7, 15189 (2017). https://doi.org/10.1038/s41598-017-15033-

Mice with Calr mutations homologous to human CALR mutations only exhibit mild thrombocytosis

Shide, K., Kameda, T., Kamiunten, A. et al. Mice with Calr mutations homologous to human CALR mutations only exhibit mild thrombocytosis. Blood Cancer J. 9, 42 (2019). https://doi.org/10.1038/s41408-019-0202-

The astrometric Gaia-FUN-SSO observation campaign of 99 942 Apophis

Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO . The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids.Comment: Accepted for publication in A&

Raft-based sphingomyelin interactions revealed by new fluorescent sphingomyelin analogs

Sphingomyelin (SM) has been proposed to form cholesterol-dependent raft domains and sphingolipid domains in the plasma membrane (PM). How SM contributes to the formation and function of these domains remains unknown, primarily because of the scarcity of suitable fluorescent SM analogs. We developed new fluorescent SM analogs by conjugating a hydrophilic fluorophore to the SM choline headgroup without eliminating its positive charge, via a hydrophilic nonaethylene glycol linker. The new analogs behaved similarly to the native SM in terms of their partitioning behaviors in artificial liquid order-disorder phase-separated membranes and detergent-resistant PM preparations. Single fluorescent molecule tracking in the live-cell PM revealed that they indirectly interact with each other in cholesterol- and sphingosine backbone–dependent manners, and that, for ∼10–50 ms, they undergo transient colocalization-codiffusion with a glycosylphosphatidylinositol (GPI)-anchored protein, CD59 (in monomers, transient-dimer rafts, and clusters), in CD59-oligomer size–, cholesterol-, and GPI anchoring–dependent manners. These results suggest that SM continually and rapidly exchanges between CD59-associated raft domains and the bulk PM