Biomedical subjects

L Capek

Publications and source records attributed to L Capek.

7 recordsLinked to original sources

PubMed2006

Structure-activity relationship in HC-SCR of NOx by TEM, O2-chemisorption, and EDXS study of Ag/Al2O3.

Ag/alumina catalysts with different silver loading (1.28-6 wt %) for lean NO reduction activity were prepared by impregnation and the incipient wetness method. Complementary HRTEM, HAADF, O2-chemisorption, and EDXS studies were applied to investigate the dependence between silver particle size and catalytic activities of the prepared materials. The catalyst with the lowest silver loading (1.28 wt %) was found to be the most active catalyst in terms of reacted NO molecules per mole of silver. On the basis of the HRTEM, HAADF, and O2-chemisorption studies it could be concluded that the mean particle size or particle size distribution of the samples alone could not explain the big difference in the activities. EDXS analyses showed on the other hand that all of the samples were very heterogeneous in terms of particle size distribution, e.g., including both small and very big particles. Furthermore, both metallic silver and mainly hexagonal silver oxide (Ag2O) were found to be present in the samples. Despite the valuable information provided by ex situ characterization of the prepared samples, it needs to be emphasized that establishing a structure-reactivity relationship for this type of catalyst requires in situ characterization.

Journal Article↗

PubMed2006

Analysis of the state and size of silver on alumina in effective removal of NOx from oxygen rich exhaust gas.

Ag/alumina catalysts with different silver contents for octane-SCR were prepared by impregnation and incipient wetness methods. Activity tests revealed that the decisive factor for high activity is not only a high dispersion of silver, but also the ability of the system to redisperse clustered silver. Determination of dispersion by TEM/HAADF and O2-chemisorption experiments resulted in values close to each other even if the results were not directly comparable. This is suggested to be due to not complete silver reduction below 700 degrees C and the samples being very heterogeneous in terms of particle size, e.g., having a bimodal size distribution. Small charged Agsigman+ clusters containing 2-8 silver atoms highly prevailed in the samples containing <2 wt% Ag and exhibiting high octane-SCR activity. In highly loaded Ag/alumina samples or those reduced and reoxidized at high temperature (>400 degrees C), large metallic particles are stabilized, resulting in poor conversion of NOx to N2.

Aluminum Oxide↗

PubMed1999

Epidemic cluster of legionnaires disease in Paris, June 1998.

From 29 June to July 1998, four cases of legionnaires disease in British citizens were reported to the Reseau National de Sante Publique (RNSP) by the statutory notification system (declaration obligatoire (DO)) and by theEuropean Surveillance Scheme for

Journal Article↗

PubMed1998

Neuroma-in-continuity resection: early outcome in obstetrical brachial plexus palsy.

The short-term effect of neuroma-in-continuity resection in obstetrical brachial plexus palsy was evaluated to test the hypothesis that the neuroma does not contribute to useful limb function. Twenty-six patients with obstetrical brachial plexus palsy underwent resection of the neuroma-in-continuity and interpositional nerve grafting, and 17 patients underwent neurolysis only. The preoperative and postoperative active movement scores were recorded using an eight-point scale for 15 joint motions in each patient. Data analysis examined the change in total limb motion scores over time within patients undergoing neuroma-in-continuity resection and a comparison with those patients undergoing neurolysis. Compared with preoperative assessment, limb motion scores after neuroma resection were significantly decreased at 6 weeks, not significantly different by 3 months, and significantly improved at 12 months postoperatively. In comparison to patients undergoing neurolysis only, limb motion scores after neuroma resection were not significantly different at 3, 6, and 12 months postoperatively. These findings are unlikely to be accounted for by axonal regeneration across interpositional nerve grafts. Nerve regeneration or recovery in the nongrafted segment of the plexus must be sufficient to reproduce preoperative motion. Resection of the neuromas-in-continuity in obstetrical brachial plexus palsy does not significantly diminish motor activity.

Brachial Plexus↗

PubMed1997

Plastic surgeons: a gender comparison.

This study surveyed plastic surgeons for the purpose of identifying gender-related differences within the specialty. A confidential 108-item questionnaire was mailed to all female members and candidates of the American Society of Plastic and Reconstructive Surgeons (ASPRS) and to an equal number of male colleagues. The survey was conducted between September of 1992 and October of 1993 using a modified Dillman five-step computerized method. The response rate was 73 percent for women (157 of 216) and 57 percent for men (124 of 216). Of those who responded, 65 percent of women and 89 percent of men were married (p < 0.01). Fifty-two percent of women and 86 percent of men had biologic children (p < 0.001). The majority of surgeons surveyed (97 percent) were in full-time surgical practice. Many women reported delaying childbearing until they had begun full-time practice of plastic surgery (p < 0.001). No significant gender-related differences were noted with respect to medical school rank, training history, advanced degrees, subspecialty practiced, hospital affiliation, or hours worked. Women surgeons in academic practice held lower rank than men and were less likely to be tenured (p < 0.04). Gross annual income was lower for women (p < 0.001). In contrast to men (27 percent), most women (89 percent) perceived sexual discrimination and harassment (p < 0.001). The majority of plastic surgeons were satisfied with their financial situation (80 percent), work (94 percent), and family life (76 percent). Over 90 percent of both women and men were happy with their career choice and would encourage medical students to become surgeons. Plastic surgeons do not differ in training or professional practice characteristics. Discrimination and harassment and unequal promotion and remuneration of women in the university environment are problems that need to be eliminated.

Adult↗

PubMed1996

The expanded forehead scalping flap: a new method of total nasal reconstruction.

The challenge of total nasal reconstruction is particularly formidable in the pediatric patient. Forehead skin is taut, and conventional methods of reconstruction, such as the midline forehead flap, provide a paucity of tissue in this age group. Tissue expansion is well-suited modification to overcome this limitation, but as applied to the midline forehead flap, it does not address the resulting vertical forehead scar. We present a new technique for total nasal reconstruction using an expanded, transversely oriented forehead scalping flap in a pediatric patient. This approach not only provides a generous amount of forehead skin but also limits donor-site morbidity and scarring by orienting incisions transversely at the hairline and within the scalp.

Child↗

PubMed1996

Endoscopic sural nerve harvest in the pediatric patient.

A technique of endoscopic sural nerve harvest was devised to minimize the donor-site scarring in pediatric patients requiring peripheral nerve-grafting procedures. The harvests were performed under tourniquet control using two 2-cm incisions for access at the lateral malleolus and the midcalf. Endoscopic visualization and blunt dissection of the nerve were achieved with a 4-mm Hopkins telescope with 30-degree angled lens (Karl Storz GmbH, Tuttlingen, Germany) stabilized in an Emory retractor and attached to a video camera. The medial sural nerve was divided in the popliteal fossa proximally under endoscopic visualization. The lateral sural nerve was identified and harvested when present. Between June of 1994 and March of 1995, 18 patients underwent 27 sural nerve harvests using the endoscopic technique. Mean patient age was 3.3 years (range 4 to 197 months). Indications for surgery included obstetrical brachial plexus palsy (12), facial palsy (5), and ulnar nerve neuroma (1). Nerve-graft length harvested ranged from 13 to 41 cm. Mean tourniquet time per limb was 92 minutes. No nerve graft injury was noted on examination under the operating microscope. Postoperative pain, swelling, and ecchymosis were minimal. Donorsite scarring has been aesthetically satisfactory to date.

Adolescent↗