Alexander Williamson: A Victorian chemist and the making of modern Japan

Alexander Williamson was professor of chemistry at UCL (1849–87) and a leading scientist of his time. He taught and cared for visiting Japanese students, thereby assisting them with their goal of modernising Japan. This short, accessible biography explores his contribution to nineteenth-century science as well as his lasting impact on Japanese society. In 1863 five students from the Chōshū clan, with a desperate desire to learn from the West, made their way to England. They were put in the care of Williamson and his wife. Their mission was to learn about cutting-edge Western technology, science, economics and politics. When they returned home they rapidly became leading figures in Japanese life at a particularly turbulent time, one of them serving as the country’s first prime minister. Subsequently many other Japanese students followed in their footsteps and studied at UCL. The remarkable story of the part Williamson and UCL played in the modernisation of Japan is little known today. This biography will promote a deeper understanding of Williamson’s scientific innovations and his legacy for Anglo-Japanese relations. An Afterword briefly outlines the extraordinary careers of the pioneering students after they left Britain

Development of a Time Projection Chamber Using Gas Electron Multipliers (GEM-TPC)

We developed a prototype time projection chamber using gas electron multipliers (GEM-TPC) for high energy heavy ion collision experiments. To investigate its performance, we conducted a beam test with 3 kinds of gases (Ar(90%)-CH4(10%), Ar(70%)-C2H6(30%) and CF4). Detection efficiency of 99%, and spatial resolution of 79 $\mu$m in the pad-row direction and 313 $\mu$m in the drift direction were achieved. The test results show that the GEM-TPC meets the requirements for high energy heavy ion collision experiments. The configuration and performance of the GEM-TPC are described.Comment: 18 pages, 12 figures, published online in Nucl. Instr. and Meth.

The ZEUS Forward Plug Calorimeter with Lead-Scintillator Plates and WLS Fiber Readout

A Forward Plug Calorimeter (FPC) for the ZEUS detector at HERA has been built as a shashlik lead-scintillator calorimeter with wave length shifter fiber readout. Before installation it was tested and calibrated using the X5 test beam facility of the SPS accelerator at CERN. Electron, muon and pion beams in the momentum range of 10 to 100 GeV/c were used. Results of these measurements are presented as well as a calibration monitoring system based on a $^{60}$Co source.Comment: 38 pages (Latex); 26 figures (ps

2,6-Diamino­pyridinium 2-carb­oxy­benzoate

In the crystal of the title mol­ecular salt, C5H8N3 +·C8H5O4 −, the diamino­pyridine cation and the phthalate anion are linked by a pair of N—H⋯O hydrogen bonds. Within the phthalate anion, an almost symmetrical O—H⋯O hydrogen bond is observed. The ion pairs are linked by further N—H⋯O hydrogen bonds, generating a two-dimensional network lying parallel to (10)

Space charge in drift chambers operated with the Xe,CO2(15%) mixture

Using prototype modules of the ALICE Transition Radiation Detector we investigate space charge effects and the dependence of the pion rejection performance on the incident angle of the ionizing particle. The average pulse height distributions in the drift chambers operated with the Xe,CO2(15%) mixture provide quantitative information on the gas gain reduction due to space charge accumulating during the drift of the primary ionization. Our results demonstrate that the pion rejection performance of a TRD is better for tracks which are not at normal incidence to the anode wires. We present detailed simulations of detector signals, which reproduce the measurements and lend strong support to our interpretation of the measurements in terms of space charge effects.Comment: 18 pages, 10 figures, accepted for publication in Nucl.Instrum.Meth. A. Data files available at http://www-alice.gsi.de/tr

The degradation of p53 and its major E3 ligase Mdm2 is differentially dependent on the proteasomal ubiquitin receptor S5a.

p53 and its major E3 ligase Mdm2 are both ubiquitinated and targeted to the proteasome for degradation. Despite the importance of this in regulating the p53 pathway, little is known about the mechanisms of proteasomal recognition of ubiquitinated p53 and Mdm2. In this study, we show that knockdown of the proteasomal ubiquitin receptor S5a/PSMD4/Rpn10 inhibits p53 protein degradation and results in the accumulation of ubiquitinated p53. Overexpression of a dominant-negative deletion of S5a lacking its ubiquitin-interacting motifs (UIM)s, but which can be incorporated into the proteasome, also causes the stabilization of p53. Furthermore, small-interferring RNA (siRNA) rescue experiments confirm that the UIMs of S5a are required for the maintenance of low p53 levels. These observations indicate that S5a participates in the recognition of ubiquitinated p53 by the proteasome. In contrast, targeting S5a has no effect on the rate of degradation of Mdm2, indicating that proteasomal recognition of Mdm2 can be mediated by an S5a-independent pathway. S5a knockdown results in an increase in the transcriptional activity of p53. The selective stabilization of p53 and not Mdm2 provides a mechanism for p53 activation. Depletion of S5a causes a p53-dependent decrease in cell proliferation, demonstrating that p53 can have a dominant role in the response to targeting S5a. This study provides evidence for alternative pathways of proteasomal recognition of p53 and Mdm2. Differences in recognition by the proteasome could provide a means to modulate the relative stability of p53 and Mdm2 in response to cellular signals. In addition, they could be exploited for p53-activating therapies. This work shows that the degradation of proteins by the proteasome can be selectively dependent on S5a in human cells, and that this selectivity can extend to an E3 ubiquitin ligase and its substrate

Energy loss of pions and electrons of 1 to 6 GeV/c in drift chambers operated with Xe,CO2(15%)

We present measurements of the energy loss of pions and electrons in drift chambers operated with a Xe,CO2(15%) mixture. The measurements are carried out for particle momenta from 1 to 6 GeV/c using prototype drift chambers for the ALICE TRD. Microscopic calculations are performed using input parameters calculated with GEANT3. These calculations reproduce well the measured average and most probable values for pions, but a higher Fermi plateau is required in order to reproduce our electron data. The widths of the measured distributions are smaller for data compared to the calculations. The electron/pion identification performance using the energy loss is also presented.Comment: 15 pages, 10 figures, accepted for publication in Nucl.Instrum.Meth.

Bis(2,6-diamino­pyridin-1-ium) hexa­aqua­cobalt(II) disulfate dihydrate

In the title compound, (C5H8N3)2[Co(H2O)6](SO4)2·2H2O, the complete complex cation is generated by crystallographic inversion symmetry, such that the CoII cation is octa­hedrally coordinated by six water mol­ecules. The organic cation is essentially planar, with a maximum deviation of 0.013 (1) Å. In the crystal structure, the ions and mol­ecules are linked into a pseudo-layered three-dimensional supra­molecular network via O—H⋯O and N—H⋯O hydrogen bonds. Weak inter­molecular π–π inter­actions further stabilize the crystal structure [centroid–centroid distance = 3.5231 (4) Å]

Position Reconstruction in Drift Chambers operated with Xe, CO2 (15%)

We present measurements of position and angular resolution of drift chambers operated with a Xe,CO$_2$(15%) mixture. The results are compared to Monte Carlo simulations and important systematic effects, in particular the dispersive nature of the absorption of transition radiation and non-linearities, are discussed. The measurements were carried out with prototype drift chambers of the ALICE Transition Radiation Detector, but our findings can be generalized to other drift chambers with similar geometry, where the electron drift is perpendicular to the wire planes.Comment: 30 pages, 18 figure