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Biomedical subjects

J Pullin

Publications and source records attributed to J Pullin.

At least 19 recordsLinked to original sources
PubMed2001

A functional polymorphism of toll-like receptor 4 is not associated with likelihood or severity of meningococcal disease.

Human Toll-like receptor 4 (TLR4) transduces proinflammatory cytokine release by human cells in response to lipopolysaccharide (LPS). This study tested the hypothesis that, if TLR4 is rate limiting for a successful response to bacterial LPS in humans, a human gene polymorphism that results in the amino acid substitution Asp299Gly and causes reduced expression and function of TLR4 should influence susceptibility to or severity of natural gram-negative infection. The allele frequency of the Asp299Gly polymorphism was 5.9% among 879 blood donors, 6.5% among 1047 patients with microbiologically proven meningococcal disease, and 4.1% among 86 patients who died of meningococcal disease. No significant differences were observed, including those analyzed after stratification of the infected population by age and by meningococcal serogroup. Therefore, this functional TLR4 polymorphism does not influence susceptibility to or severity of meningococcal disease.

Adolescent↗
PubMed2000

Grazing collisions of black holes via the excision of singularities.

We present the first simulations of non-head-on (grazing) collisions of binary black holes in which the singularities are excised from the simulation. Initially equal mass m black holes (spinning or not) are separated by approximately 10m and with impact parameter approximately 2m. Evolutions to t approximately 35m are obtained where two separate horizons are present for t approximately 3.8m; then a single enveloping horizon forms indicating that the holes merged. Apparent horizon area estimates suggest gravitational radiation of about 2%-3% of the total mass. The evolutions end after a moderate amount of time because of instabilities.

Journal Article↗
PubMed2000

Making classical and quantum canonical general relativity computable through a power series expansion in the inverse cosmological constant.

We consider general relativity with a cosmological constant as a perturbative expansion around a completely solvable diffeomorphism invariant field theory. This theory is the lambda --> infinity limit of general relativity. This allows an explicit perturbative computational setup in which the quantum states of the theory and the classical observables can be explicitly computed. An unexpected relationship arises at a quantum level between the discrete spectrum of the volume operator and the allowed values of the cosmological constant.

Journal Article↗
PubMed2000

Consistent canonical quantization of general relativity in the space of vassiliev invariants

We present a quantization of the Hamiltonian and diffeomorphism constraint of canonical quantum gravity in the spin network representation. The novelty consists in considering a space of wave functions based on the Vassiliev invariants. The constraints are finite, well defined, and reproduce at the level of quantum commutators the Poisson algebra of constraints of the classical theory. A similar construction can be carried out in 2+1 dimensions leading to the correct quantum theory.

Journal Article↗
PubMed1995

The use of a structured assessment interview as an intervention to reduce dropout rates in outpatient relapse prevention groups for "problem" drinkers.

The problem of dropout rates in outpatient relapse prevention groups for "problem" drinkers is addressed. To test the hypothesis that the dropout rates were due to anxiety and lack of clarity among the participants about the purpose and expectations of the group, a structured induction was developed. The results obtained show that the induction made a significant difference in reducing the dropout rate. These findings can also be applied to other outpatient groups.

Adult↗