Biomedical subjects

R Besseling

Publications and source records attributed to R Besseling.

4 recordsLinked to original sources

PubMed2003

Dynamic melting of confined vortex matter.

We study dynamic melting of confined vortex matter moving in disordered, mesoscopic channels by mode-locking experiments. The dynamic melting transition, characterized by a collapse of the mode-locking effect, strongly depends on the frequency, i.e., on the average velocity of the vortices. The associated dynamic ordering velocity diverges upon approaching the equilibrium melting line T(m,e)(B) as v(c) approximately (T(m,e)-T)(-1). The data provide the first direct evidence for velocity dependent melting and show that the phenomenon also takes place in a system under disordered confinement.

Journal Article↗

PubMed2002

Mode locking of vortex matter driven through mesoscopic channels.

We investigated the driven dynamics of vortices confined to mesoscopic flow channels by means of a dc-rf interference technique. The observed mode-locking steps in the IV curves provide detailed information on how both the number of vortex rows and the lattice structure in each flow channel change with magnetic field. Minima in flow stress occur when an integer number of rows is moving coherently, while maxima appear when the incoherent motion of mixed n and n+/-1 row configurations is predominant. Simulations show that the enhanced pinning at mismatch originates from quasistatic fault zones with misoriented edge dislocations induced by disorder in the channel edges.

Journal Article↗

PubMed2002

Intraoperative scrape cytology of the sentinel lymph node in patients with breast cancer.

BACKGROUND: Intraoperative examination of the sentinel lymph node (SLN) may detect metastatic disease, allowing immediate axillary lymph node dissection and therefore avoiding the need for reoperation. The aim of this study was to evaluate the accuracy of scrape cytology of the SLN in patients with early breast cancer. METHODS: Sentinel node biopsy was performed in 148 patients with clinical T1-2 N0 breast cancer. After harvesting, the SLN was bisected and cells from both halves were scraped with a scalpel blade on to a slide and stained with a Papanicolaou and Giemsa stain. Scrape cytology results were compared with the results of paraffin sections stained with haematoxylin and eosin and with immunohistochemistry. RESULTS: The intraoperative diagnosis was correct in 126 patients (85 per cent). Sensitivity and specificity were 67 and 98 per cent respectively; positive and negative predictive values were 95 and 81 per cent. CONCLUSION: Scrape cytology is a useful method for intraoperative evaluation of the SLN in patients with breast cancer.

Adult↗

PubMed1997

Histologic processing of microbiopsies from cervical smears is diagnostically useful in selected cases.

We analyzed the value in cervical cytology of a recently developed technique by which it is possible to remove thick tissue specimens, called microbiopsies, from cervical smears and to process them for histologic examination. In 12 (48%) of 25 cervical smears in which microbiopsies were found, the histologic sections from them confirmed the cytologic diagnosis. Most cases involved classification of lesions diagnosed as cervical intraepithelial neoplasia. In 13 (52%) of 25 smears, processing the microbiopsy allowed considerable modification of the cytologic diagnosis. In six of these cases, microbiopsies consisted of groups of columnar cells that were incorrectly classified as atypical on the basis of cytologic criteria. After histologic processing, the microbiopsies revealed nonatypical columnar cells in four cases and only mildly atypical columnar cells in two cases. In 3 of 13 smears, there were insufficient dispersed atypical cells for a conclusive diagnosis. Processing the microbiopsies in these cases allowed classification into one of the cervical intraepithelial neoplasia categories.

Biopsy↗