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Biomedical subjects

S Kowalski

Publications and source records attributed to S Kowalski.

At least 19 recordsLinked to original sources
PubMed2001

Relativistic effects and two-body currents in (H)((-->)e(')p)n using out-of-plane detection.

Measurements of the (2)H((-->)e,e(')p)n reaction were performed with the out-of-plane magnetic spectrometers (OOPS) at the MIT-Bates Linear Accelerator. The longitudinal-transverse, f(LT) and f(')(LT), and the transverse-transverse, f(TT), interference responses at a missing momentum of 210 MeV/c were simultaneously extracted in the dip region at Q2 = 0.15 (GeV/c)(2). In comparison to models of deuteron electrodisintegration, the data clearly reveal strong effects of relativity and final-state interactions and the importance of two-body meson-exchange currents and isobar configurations. We demonstrate that such effects can be disentangled by extracting these responses using the novel out-of-plane technique.

Journal Article↗
PubMed2001

Search for quadrupole strength in the electroexcitation of the delta+(1232).

High-precision 1H(e,e'p)pi(0) measurements at Q2 = 0.126 (GeV/c)2 are reported, which allow the determination of quadrupole amplitudes in the gamma*N-->Delta transition; they simultaneously test the reliability of electroproduction models. The derived quadrupole-to-dipole ( I = 3/2) amplitude ratios, R(SM) = (-6.5+/-0.2(stat+sys)+/-2.5(mod))% and R(EM) = (-2.1+/-0.2(stat+sys)+/-2.0(mod))%, are dominated by model error. Previous R(SM) and R(EM) results should be reconsidered after the model uncertainties associated with the method of their extraction are taken into account.

Journal Article↗
PubMed2000

Strange magnetism and the anapole structure of the proton.

The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.

Journal Article↗
PubMed2000

Parity violation in elastic electron-proton scattering and the Proton's strange magnetic form factor

We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92+/-0.61+/-0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections.

Journal Article↗
PubMed2000

[Case report: the spontaneous course of a giant myelolipoma].

Adrenal myelolipomas are rare benign, non functioning tumors, mostly small and asymptomatic. We report the natural history of a giant adrenal myelolipoma. We could follow with CT the natural progression of the tumor during a 5-year interval.

Adrenal Gland Neoplasms↗
PubMed1998

Spinal epidural haematoma in haemophilia A.

We report on a 27-year-old male Caucasian with severe haemophilia A who presented with acute onset of neck pain with cervical nerve root irritation, due to a spinal epidural haematoma. His past medical history revealed carrying of a moderate weight as a possible traumatic mechanism. Under immediate factor VIII replacement therapy complete remission of the symptoms was achieved within several days. The diagnosis of spinal epidural haematoma and complete resorption was revealed by initial and follow-up magnetic resonance imaging studies of the cervical spine. Having reviewed the literature on spinal epidural haematoma, we present an overview of the treatment and outcome as regards haemophilia.

Adult↗
PubMed1994

An accountability server for health care information systems.

The paper starts off by first briefly discussing the necessary ethical, legal and administrative/management controls that are required before the mechanisms of accountability controls can be implemented in automated clinical patient record systems. After these social aspects are discussed the technical aspects of the ALS are outlined. The security concepts of the ECMA framework are reviewed and used to explain the technical design of the ALS. A walk-through of the server in a typical patient record transaction is used to explain the operations of the server. The paper concludes with a general discussion of the usefulness of accountability mechanisms in making security in health care information work in practice.

Computer Communication Networks↗
PubMed1993

Molecular typing of Chlamydia trachomatis by random amplification of polymorphic DNA.

The random amplification of polymorphic DNA (RAPD) was used for epidemiological typing of Chlamydia trachomatis strains. DNA samples from 39 C. trachomatis, 1 C. pneumoniae and 2 C. psittaci strains were screened by the use of 4 single 10-mer primers. Different and reproducible banding profiles were observed on agarose gel electrophoresis. No common profiles were recorded for strains from different Chlamydia species. All C. trachomatis strains of trachoma biovar were distinguished from lymphogranuloma venereum biovar. Moreover, serotypes A to C were separated from serotypes D to K, and some groups of strains sharing the same serotype D to K were further subdivided by RAPD. Conversely, strains of different serotypes could produce identical patterns of amplification, indicating that RAPD did not reflect serotyping. The patterns of amplified products were compared to the restriction fragment length polymorphism of the omp1 gene after amplification and to DNA fingerprinting by use of ribosomal RNA or randomly cloned DNA probes. RAPD seemed to be an alternative molecular typing procedure for epidemiological study and strain identification in urogenital infections due to serotypes D to K.

Chlamydia trachomatis↗