Structure of LaMo(2)O(5) Containing Both Isolated Mo(6)O(18) Clusters and Sheets of Fused Triangular Mo(3) Clusters.

The structure of the disordered lanthanum molybdate, LaMo(2)O(5), has been solved and refined using powder neutron diffraction data collected at 300 K. The average structure is described in P6(3)/mmc, a = 8.373(1) Å, c = 19.

The murine autologous mixed lymphocyte response: distribution of stimulator cells.

Previous studies have shown that neonatal, but not adult, murine thymic T cells proliferate when co-cultured with syngeneic, adult splenic B cells. Evidence suggests that expansion of such self-reactive T cells precedes their clonal deletion or functional inactivation (anergy). This mechanism may be of particular significance for establishing peripheral (extrathymic) tolerance.

Rapid restoration of B-cell function in XID mice by intravenous transfer of peritoneal cavity B cells.

The primary method employed to correct immune deficiency is bone marrow transfer. Depending upon the exact nature of the immune deficiency, however, alternative cell sources may be used to provide a more rapid reconstitution of immune function. In this report, peritoneal cavity (PerC) B cells are shown to be effective in the rapid emendation of the B-cell defect exhibited by XID mice.

The autologous mixed lymphocyte response: delayed T cell tolerance to B cells in XID mice.

The autologous mixed lymphocyte response (AMLR) is characterized by the proliferation of neonatal, but not adult, thymic T cells when cocultured with adult syngeneic B cells. Studies of the AMLR have revealed a temporal correlation between loss of T cell self-reactivity and development of stimulatory B cells. Such observations impart a role for B cells in the development of T cell tolerance.

VH11 bias and normal V-D-J junctions in SCID B lymphocytes rescued by neonatal T cell transfer.

The scid mutation interferes with normal rearrangement of antigen receptor genes, leading to an absence of T and B lymphocytes in most SCID mice. However, the SCID phenotype is "leaky", with an age- and strain-dependent increase in the incidence of mice with small number of T and B cells and readily detectable serum immunoglobulin. Introduction of neonatal T cells into young SCID mice results in a 100% incidence of the leaky phenotype.

Termination of life-sustaining medical treatment: who should exercise a patient's right to die?

Due to changes in the medical field introduced by the biotechnological revolution that enable physicians to prolong a patient's life artificially, courts are increasingly being called on to resolve disputes between the families of incompetent patients and the hospitals and medical personnel who are caring for them. This article discusses the significant court decisions involving the right to die and analyzes the various legislative responses to this issue. It concludes that an individual who desires to determine the timing of his or her own death should execute a living will, coupled with a durable power of attorney or proxy directive.

B cell function in SCID mice reconstituted with allotype-disparate spleen and peritoneal cavity B cells.

Severe combined immune-defective (SCID) mice reconstituted with immunoglobulin heavy chain-disparate spleen (SP) and peritoneal cavity (PerC) B cells exhibit serologic dominance of IgM bearing the PerC allotype. Immunization fails to elicit IgM production from donor SP B cells although flow cytometric analyses indicate the presence of these cells in the spleen of (SP + PerC)-->SCID chimeras. This observation suggests that donor SP B cell function is absent or inhibited in the SCID chimera.

Influences of hypothyroidism on the taste detection performance of rats: a signal detection analysis.

The influences of hypothyroidism on behavioral measures of the taste function in male and female Long-Evans rats were determined. Experimental rats' preferences for and ability to detect NaCl, HCl, sucrose, and quinine sulfate were examined before, during, and after 9 weeks of maintenance on 0.1% propylthiouracil (PTU), an agent that produces marked hypothyroidism, with similar determinations made for control animals.

Methyl xanthine, adenosine, and human taste responsivity.

The influences of three methyl xanthines (MX) on human taste responsivity, caffeine, theophylline, and theobromine, were examined using blind control procedures. Taste responsivity in the same subjects was determined using the matching procedure described by Schiffman (Study 1) and the whole-mouth procedure described by Sheperd (Study 2). In each study, the duration of MX pretreatment necessary to enhance taste responsivity was examined.

Decreased NaCl sensitivity in zinc-deprived rats.

NaCl thresholds and ability to discriminate between NaCl and sucrose were assessed in rats using an operant discrimination conditioning procedure before and during moderate and severe zinc deprivation and during zinc supplementation. NaCl thresholds were approximately 1 mM before dietary zinc manipulation. They increased in all zinc-deprived rats tested 10 and 17 days after initiation of deprivation but did not change in pair-fed controls maintained on supplemental zinc.

The effects of child health on marital status and family structure.

The purpose of this paper is to provide evidence on the effect of child health on marital stability and family structure in an economic framework. We use the 1988 National Health Interview Survey's Child Health Supplement, with a sample of about 9,000 families, to test whether having an unhealthy child decreases the mother's chance of being married and whether it increases her chance of living in an extended family. Using two different measures of child health, we find that having an unhealthy child decreases the mother's likelihood of being married.

Changes in learning-style preferences: comments on Geiger and Pinto.

Geiger and Pinto reached unwarranted conclusions regarding changes in learning-style preferences over a two-year period. Problems with the instrument and data analysis require a revision of their conclusions.

Quality-specific differences in rat taste detection performance as a function of stimulus volume.

Taste detection performance for representatives of the four taste qualities as a function of stimulus volume (5 x 10(-4) to 1 x 1(-1) ml) was examined in rats using high-precision gustometry, computer-controlled operant procedures, nonparametric signal detection measures of sensitivity and responsivity, and blind control procedures. The overall sensitivity index was positively related to stimulus volume (rs = .60), with optimal detection performance attained with a 5 x 10(-3) ml stimulus volume for salty tastants and a 1 x 10(-2) ml stimulus volume for the other taste qualities.

Acquisition and retention of perceptual learning and the horizontal-vertical illusion.

The present study examined procedure-specific differences in the acquisition and retention of perceptual learning using four forms of the Horizontal-Vertical illusion. Training to criterion was conducted using intertrial feedback, continued visual inspection, or yoked-control procedures. Retention of perceptual learning was assessed at posttraining intervals ranging from 1 minute to 1 month.

Higgs-boson production in nucleus-nucleus collisions.

Cross-section calculations are presented for the production of intermediate-mass Higgs bosons produced in ultrarelativistic nucleus-nucleus collisions via two-photon fusion. The calculations are performed in position space using Baur's method for folding together the Weizsacker-Williams virtual-photon spectra of the two colliding nuclei. It is found that two-photon fusion in nucleus-nucleus collisions is a plausible way of finding intermediate-mass Higgs bosons at the Superconducting Super Collider or the CERN Large Hadron Collider.

Life, death, and liability: duties of health care providers regarding withdrawal of treatment.

Many of the issues surrounding refusal and withdrawal of medical treatment are so new and complex that the U.S. society has not resolved the ethical or legal questions involved.

Charge dependence and electric quadrupole effects on single-nucleon removal in relativistic and intermediate energy nuclear collisions.

Single-nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsäcker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed.

Taste detection and discrimination performance of rats following selective desalivation.

Taste sensitivity and responsivity, two-tastant and taste-mixture discrimination performance, and taste preferences were examined prior to and after the selective desalivation of 48 male Long-Evans rats. Altered preference behavior was observed in rats after removal of the major salivary glands, as well as after removal of only the submandibular-sublingual complexes. In 9 of 12 desalivated rats, decreased sensitivity and increased responsivity to near-threshold sodium chloride solutions were observed, although these changes were less than one-half an order of magnitude.

Single nucleon emission in relativistic nucleus-nucleus reactions.

Significant discrepancies between theory and experiment have previously been noted for nucleon emission via electromagnetic processes in relativistic nucleus-nucleus collisions. The present work investigates the hypothesis that these discrepancies have arisen due to uncertainties about how to deduce the experimental electromagnetic cross section from the total measured cross section. An optical-model calculation of single neutron removal is added to electromagnetic cross sections and compared to the total experimental cross sections.

Electric quadrupole excitations in relativistic nucleus-nucleus collisions.

Calculations are presented for electric quadrupole excitations in relativistic nucleus-nucleus collisions. The theoretical results are compared to an extensive data set and it is found that electric quadrupole effects provide substantial corrections to cross sections, especially for heavier nuclei.

Category Headings as Recall Cues: A Test of the Principle of Encoding Specificity.

Input and output cues were factorially varied in the free and cued recall of a list of 48 words in order to test the principle of encoding specificity. In each of two experiments 20 college students (10 male, 10 female) sorted 32 words under eight taxonomic category headings and 16 words under the heading "uncategorized." One-half of the categorized items and one-half of the uncategorized items were then cued at recall with appropriate taxonomic category headings.