Lyb-2 system of mouse B cells. Evidence for a role in the generation of antibody-forming cells

The Lyb-2 cell-surface alloantigens of the mouse are selectively and perhaps exclusively expressed in the B lymphocyte lineage, but not on antibody- forming cells. Thus if the Lyb-2 molecule is concerned in specific B cell function, it must participate in the generative phase of the antibody response. Accordingly, monoclonal Lyb-2 antibody was found to depress the plaque- forming cell (PFC) response to sheep erythrocytes in 5-d Mishell-Dutton assays when added within the first 3 d of culture, but not later. The rate of PFC generation was not affected, signifying an absolute reduction in the number of PFC generated. Because reduction of PFC counts by Lyb-2 antibody was not affected by exclusion of Lyt-2(+) T cells, it is unlikely that the reduction depends on augmented suppression by T cells. Augmented B cell- mediated suppression is also unlikely, because the PFC response of serial combinations of congenic Lyb-2.1 and Lyb-2.2 cells, in the presence of monoclonal Lyb-2.1 antibody, was reduced only in direct proportion to the number of Lyb-2.1 cells present. The PFC response of Lyb-2.1/Lyb-2.2 heterozygous cells was not reduced by Lyb-2.1 antibody, presumably because generation of PFC is impeded only if most Lyb-2 sites are blocked. Further evidence that the molecule identified by Lyb-2 plays a critical role in the generation of antibody-forming cells (AFC) in response to T-dependent antigen comes from the finding that Lyb-2 antibody does not reduce the PFC response to the T-independent antigens trinitrophenylated (TNP) Brucella abortus and TNP-FicolI, although elimination of Lyb-2(+) cells from the starting population by Lyb-2 antibody and complement reduces the PFC response to T- dependent and T-independent antigens alike

Benzyl N-{(1S)-2-hy­droxy-1-[N′-(2-nitro­benzyl­idene)hydrazinylcarbon­yl]eth­yl}carbamate

The carbamate and hydrazone groups in the title compound, C18H18N4O6, are approximately orthogonal [dihedral angle = 83.3 (4)°], and the carbonyl groups are effectively anti [O=C⋯C=O torsion angle = −116.2 (7)°]. The conformation about the imine bond [1.295 (11) Å] is E. The crystal packing is dominated by O—H⋯O and N—H⋯O hydrogen bonding, which leads to two-dimensional arrays in the ab plane

Benzyl N-[(S)-2-hy­droxy-1-({[(E)-2-hy­droxy-4-meth­oxy­benzyl­idene]hydrazin­yl}carbon­yl)eth­yl]carbamate

The shape of the title compound, C19H21N3O6, is curved with the conformation about the imine bond [1.291 (3) Å] being E. While the hy­droxy-substituted benzene ring is almost coplanar with the hydrazinyl residue [N—N—C—C = 177.31 (18)°], an observation correlated with an intra­molecular O—H⋯N hydrogen bond leading to an S(6) ring, the remaining residues exhibit significant twists. The carbonyl residues are directed away from each other as are the amines. This allows for the formation of O—H⋯O and N—H⋯O hydrogen bonds in the crystal, which lead to two-dimensional supra­molecular arrays in the ac plane. Additional stabilization to the layers is afforded by C—H⋯π inter­actions

tert-Butyl N-((1S)-2-hy­droxy-1-{N′-[(1E)-4-meth­oxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate

The mol­ecule of the title compound, C16H23N3O5, is twisted about the chiral C atom, the dihedral angle formed between the amide residues being 79.6 (3)°. The conformation about the imine bond [1.278 (5) Å] is E. In the crystal, O—H⋯O and N—H⋯O hydrogen bonding between the hy­droxy, amine and carbonyl groups leads to the formation of supra­molecular layers, which stack along the c-axis direction

Benzyl N-(2-hy­droxy-1-{N′-[(1E)-2-hy­droxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate

The mol­ecule of the title compound, C18H19N3O5, adopts a curved arrangement with the terminal benzene rings lying to the same side. The hydroxyl­benzene ring is close to coplanar with the adjacent hydrazine residue [dihedral angle = 11.14 (12)°], an observation which correlates with the presence of an intra­molecular O—H⋯N hydrogen bond. The benzyl ring forms a dihedral angle of 50.84 (13)° with the adjacent carbamate group. A twist in the mol­ecule, at the chiral C atom, is reflected in the dihedral angle of 80.21 (12)° formed between the amide residues. In the crystal, two-dimensional arrays in the ac plane are mediated by O—H⋯O and N—H⋯O hydrogen bonds

Benzyl N-(1-{N′-[(E)-2-chloro­benzyl­idene]hydrazinecarbon­yl}-2-hy­droxy­eth­yl)carbamate

The mol­ecule of the title compound, C18H18ClN3O4, is twisted about the chiral C atom with the dihedral angle between the two amide residues being 87.8 (5)°, but, overall, it can be described as curved, with the benzene rings lying on the same side of the mol­ecule [dihedral angle = 62.8 (4)°]. The conformation about the imine bond [1.294 (7) Å] is E. In the crystal, a two-dimensional array in the ab plane is mediated by O—H⋯O and N—H⋯O hydrogen bonds as well as C—H⋯Cl inter­actions. The layers stack along the c-axis direction, being connected by C—H⋯.π contacts

tert-Butyl N-{(1S)-1-[(2,4-dihy­droxy­benzyl­idene)hydrazinecarbon­yl]-2-hy­droxy­eth­yl}carbamate ethanol monosolvate

The mol­ecule of the title ethanol solvate, C15H21N3O6·C2H6O, adopts a curved shape; the conformation about the imine bond [N=N = 1.287 (3) Å] is E. The amide residues occupy positions almost orthogonal to each other [dihedral angle = 85.7 (2)°]. In the crystal, a network of O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds leads to the formation of supra­molecular arrays in the ab plane with the ethanol mol­ecules lying to the periphery on either side. Disorder in the solvent ethanol mol­ecule was evident with two positions being resolved for the C atoms [site occupancy of the major component = 0.612 (10)]

Coincidence analysis to search for inspiraling compact binaries using TAMA300 and LISM data

Japanese laser interferometric gravitational wave detectors, TAMA300 and LISM, performed a coincident observation during 2001. We perform a coincidence analysis to search for inspiraling compact binaries. The length of data used for the coincidence analysis is 275 hours when both TAMA300 and LISM detectors are operated simultaneously. TAMA300 and LISM data are analyzed by matched filtering, and candidates for gravitational wave events are obtained. If there is a true gravitational wave signal, it should appear in both data of detectors with consistent waveforms characterized by masses of stars, amplitude of the signal, the coalescence time and so on. We introduce a set of coincidence conditions of the parameters, and search for coincident events. This procedure reduces the number of fake events considerably, by a factor $\sim 10^{-4}$ compared with the number of fake events in single detector analysis. We find that the number of events after imposing the coincidence conditions is consistent with the number of accidental coincidences produced purely by noise. We thus find no evidence of gravitational wave signals. We obtain an upper limit of 0.046 /hours (CL $= 90$) to the Galactic event rate within 1kpc from the Earth. The method used in this paper can be applied straightforwardly to the case of coincidence observations with more than two detectors with arbitrary arm directions.Comment: 28 pages, 17 figures, Replaced with the version to be published in Physical Review

Stable Operation of a 300-m Laser Interferometer with Sufficient Sensitivity to Detect Gravitational-Wave Events within our Galaxy

TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated with sufficient sensitivity to detect gravitational-wave events within our galaxy and sufficient stability for observations; the interferometer was operated for over 10 hours stably and continuously. With a strain-equivalent noise level of $h\sim 5 \times 10^{-21} /\sqrt{\rm Hz}$, a signal-to-noise ratio (SNR) of 30 is expected for gravitational waves generated by a coalescence of 1.4 $M_\odot$-1.4 $M_\odot$ binary neutron stars at 10 kpc distance. %In addition, almost all noise sources which limit the sensitivity and which %disturb the stable operation have been identified. We evaluated the stability of the detector sensitivity with a 2-week data-taking run, collecting 160 hours of data to be analyzed in the search for gravitational waves.Comment: 5 pages, 4 figure