Biomedical subjects

D J Goossens

Publications and source records attributed to D J Goossens.

5 recordsLinked to original sources

PubMed2006

Simultaneous fitting of X-ray and neutron diffuse scattering data.

Conventional crystallographic refinement uses the Bragg-peak intensities and gives the single-site average crystal structure. Information about short-range order and local order is contained in the diffuse scattering that is distributed throughout reciprocal space. Models of the short-range order in materials can now be automatically refined. The complementarity of X-ray and neutron diffraction data, and the value of simultaneously refining a structural model against both types of data, has long been known. This paper presents the first refinement of a short-range-order model against comprehensive X-ray and neutron diffuse scattering data simultaneously. The sample is the organic molecular crystal benzil, C(14)H(10)O(2) (for neutron work H is replaced by D). The technique gives new insights into local order in crystalline materials, including the dynamic correlation structure indicative of the dynamics of molecules in the crystalline state, and successfully overcomes limitations of using only the X-ray data set.

Crystallography, X-Ray↗

PubMed2003

High-energy diffuse scattering on the 1-ID beamline at the advanced photon source.

This paper reports on experiments in which high-energy (65.35 keV) X-rays were used to record the detailed diffuse diffraction patterns of a number of ceramic materials. The methodology has enabled a greater q-range to be explored (up to sintheta/lambda approximately 0.97) than is possible with laboratory-based experiments, with better q-space resolution and increased sensitivity, thus allowing previously unseen detail in diffraction patterns to be recorded. In all, 11 sections of data have been collected for Ca-CSZ, eight for Y-CSZ and six for wüstite.

Journal Article↗

PubMed2001

Diffuse X-ray scattering from benzil, C(14)H(10)O(2): analysis via automatic refinement of a Monte Carlo model.

A recently developed method for fitting a Monte Carlo computer-simulation model to observed single-crystal diffuse X-ray scattering has been used to study the diffuse scattering in benzil, diphenylethanedione, C(6)H(5)-CO-CO-C(6)H(5). A model involving 13 parameters consisting of 11 intermolecular force constants, a single intramolecular torsional force constant and a local Debye-Waller factor was refined to give an agreement factor, R = [summation operator omega(Delta I)(2)/summation operator omega I(obs)(2)](1/2), of 14.5% for 101,324 data points. The model was purely thermal in nature. The analysis has shown that the diffuse lines, which feature so prominently in the observed diffraction patterns, are due to strong longitudinal displacement correlations. These are transmitted from molecule to molecule via a network of contacts involving hydrogen bonding of an O atom on one molecule and the para H atom of the phenyl ring of a neighbouring molecule. The analysis also allowed the determination of a torsional force constant for rotations about the single bonds in the molecule. This is the first diffuse scattering study in which measurement of such internal molecular torsion forces has been attempted.

Journal Article↗

PubMed1996

Long-term survival after bronchial sleeve resection: univariate and multivariate analyses.

BACKGROUND: Long-term results after bronchial sleeve resection remain controversial, especially in relation to nodal involvement. In a previous report, there were no 10-year survivors among patients with N1 or N2 disease. METHODS: From 1960 to 1989, 145 patients underwent bronchial sleeve resection for a bronchogenic tumor. Follow-up was updated until the end of 1994, so the minimum follow-up was 5 years for surviving patients. A univariate analysis and a multivariate analysis were performed. RESULTS: For the whole group, 5-year, 10-year, and 15-year survival rates were 46%, 33%, and 22%, respectively. The median survival time was 53 months. Five-year and 10-year survival rates for the 71 patients with no disease were 62% and 51%, respectively; for the 58 patients with N1 disease, 31% and 10%; and for the 16 patients with N2 disease, 5-year and 7-year survival rates were 31% and 13%. There was a highly significant difference in survival between patients with no and N1 or N2 disease but not between those with N1 and N2 disease. Multivariate analysis showed only nodal stage and patient age to be significant factors in relation to survival. CONCLUSIONS: Long-term results after bronchial sleeve resection are influenced chiefly by nodal stage. A significantly lower survival is found in patients with N1 and N2 disease, and most of these patients die of distant metastases.

Actuarial Analysis↗

PubMed1994

Tetraplegia after a tracheal resection procedure.

We describe a 27-year-old patient who was admitted to our hospital for a tracheal stenosis caused by an adenocystic carcinoma. A tracheal resection procedure was performed and the head was fixed to the anterior chest wall by two sutures. Postoperatively he became tetraplegic, from which he completely recovered after the sutures were removed. We think that the decreased blood flow in the arterial spinal artery with flexion of the neck in combination with hypotension was the direct cause of this major complication.

Adult↗