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1.
J Biol Regul Homeost Agents ; 34(5 Suppl. 3): 137-146. Technology in Medicine, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33386044

RESUMEN

Nutritive sucking is a fundamental process assuring the primary infant nourishment in the first months of life. When feeding is impaired for pathological conditions, the growth of the infant may be delayed with a cascade effect on the overall development. While literature studied nutritive sucking development in infants with feeding problems, like in severe premature babies or with low weight at birth, few works assesses to what extent different feeding bottles may influence feeding performance of healthy new-borns. This work proposes a method for functional characterization of feeding bottles based on the most promising and reliable indices used to quantitatively assess feeding skills in clinical applications. Thirty healthy newborns have been fed with two different bottles instrumented with a device for feeding monitoring. Their impact on feeding performance is objectively assessed and discussed. The approach presented here, even if preliminary, paves the way to a new method for functional characterization of feeding bottles. Further studies may allow to confirm our analyses with a higher number of bottles and infants.


Asunto(s)
Recien Nacido Prematuro , Conducta en la Lactancia , Alimentación con Biberón , Humanos , Lactante , Recién Nacido
2.
Phys Rev Lett ; 108(14): 145001, 2012 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-22540798

RESUMEN

X-ray Thomson scattering has enabled us to measure the temperature of a shocked layer, produced in the laboratory, that is relevant to shocks emerging from supernovas. High energy lasers are used to create a shock in argon gas which is probed by x-ray scattering. The scattered, inelastic Compton feature allows inference of the electron temperature. It is measured to be 34 eV in the radiative precursor and ∼60 eV near the shock. Comparison of energy fluxes implied by the data demonstrates that the shock wave is strongly radiative.

3.
Biomed Mater Eng ; 18(3): 137-48, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18725694

RESUMEN

Ultra high molecular weight polyethylene, both pure and electron beam irradiated, was exposed to air and hyaluronic acid. Physical and mechanical analyses were performed in order to check the polymeric change due to the treatment. Pure UHMWPE, in fact, was modified by the hyaluronic acid that plasticizes the polymer. The electron irradiation cross links the chains and prevents their sliding in acid presence. A low irradiation dose is preferable rather than an high one. Low doses induce low amount of free radicals, witch react with oxygen and hyaluronic acid inducing low polymer degrade maintaining the initial mechanical performance. High doses degrade significantly the polymer properties.100 kGy irradiation in air can be applicable on the polyethylene as well as a compromise between the low mechanical performance improving and the material degradation.


Asunto(s)
Electrones , Ácido Hialurónico/efectos adversos , Polietilenos/efectos de la radiación , Aire , Fenómenos Biomecánicos , Radicales Libres/química , Ácido Hialurónico/química , Materiales Manufacturados/efectos de la radiación , Ensayo de Materiales , Polietilenos/química , Dosis de Radiación , Radiación Ionizante , Propiedades de Superficie/efectos de la radiación
4.
Biomed Mater Eng ; 16(5): 349-58, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17075170

RESUMEN

In this work composite materials, based on quartz fibers and epoxy resins, were employed with the aim to restore damaged teeth. The composite materials were chosen because they show biomechanical features very similar to that of the dentine, the main constituent of the tooth. Extracted teeth were rebuilt with two different restorative procedures: in the first, the composite material was pre-formed in a conical trunk shape abutment (PA) and then bonded to a fiber quartz post with a dental bonder. In the second rebuilt system the abutment was prepared by cross linking the resin on the fiber quartz post with a halogen lamp (CRA). The restored teeth were then mechanically tested and observed with a Scanning Electron Microscope (SEM) with the aim to study the interaction between the reconstructive materials. Wetting and roughness measurements were also carried out in order to study the interface adhesion between the post and the abutments. Characterization analysis evidenced that the CRA restorative procedure improves the adhesion between the substitutive materials and shows higher fracture strength than the PA ones. Anyway both the rebuilt systems are able to support the masticator load. An explanation of the interfacial post-abutment interaction phenomenon is discussed.


Asunto(s)
Diente Premolar/fisiología , Restauración Dental Permanente/instrumentación , Restauración Dental Permanente/métodos , Resinas Epoxi/química , Cuarzo/química , Adhesividad , Fenómenos Biomecánicos , Fuerza Compresiva , Elasticidad , Dureza , Humanos , Técnicas In Vitro , Ensayo de Materiales , Estrés Mecánico , Propiedades de Superficie , Resistencia a la Tracción
5.
Obstet Gynecol ; 87(2): 286-90, 1996 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8559540

RESUMEN

OBJECTIVE: To assess the risk of Bartholin gland carcinoma in postmenopausal women. METHODS: A referral patient population from a tertiary care cancer center and a hospital-based regional tumor registry was used in a case-control and retrospective cohort study. We searched for data on any discharge diagnosis or procedures involving the Bartholin gland, including excision, cystectomy, or marsupialization, and pathology reports confirming cancer diagnoses from a hospital-based regional tumor registry and a tertiary hospital's medical records department and operating room log. RESULTS: A total of 284 patients were identified, 161 patients from the hospital-based tumor registry and 123 from the tertiary hospital data bases. Pathology reports from 104 of the 161 patients with vulvar cancer were available and revealed two primary adenocarcinomas in postmenopausal women, one squamous cell carcinoma of the Bartholin gland in a postmenopausal woman, and two squamous cell carcinomas of the Bartholin gland in premenopausal patients over a 24-year period. Based on local New York State Department of Health census data, the incidence of Bartholin gland carcinoma was 0.023 per 100,000 woman-years in premenopausal women and 0.114 per 100,000 woman-years in postmenopausal women (incidence rate ratio 5.01, 95% confidence interval [CI] 0.67-25.1). The overall incidence rate of squamous cell vulvar carcinoma was 0.42 per 100,000 woman-years in premenopausal and 4.72 per 100,000 woman-years in postmenopausal women (odds ratio [OR] 11.55, 95% CI 7.82-17.14). The ratio of Bartholin gland cancer to other vulvar cancers was two per 37 in premenopausal women versus three per 124 in postmenopausal women (OR 2.3, 95% CI 0.39-17.9). Of thirteen postmenopausal patients (mean age 65.4 years) with Bartholin gland enlargement admitted to the tertiary care center, only four (30.8%) had excisions, whereas the remainder (69.2%) had drainage or marsupialization. None of the patients treated with drainage or marsupialization were listed subsequently in the tumor registry as developing Bartholin gland cancer during a median surveillance of 10.3 years (range 1.7-14.4). CONCLUSION: Bartholin gland cancer is exceedingly rare in all women, including postmenopausal women. We were unable to find evidence that would justify excision as the initial treatment of a Bartholin gland enlargement in postmenopausal women. Drainage and selective biopsy may be sufficient as initial management.


Asunto(s)
Glándulas Vestibulares Mayores/patología , Posmenopausia , Neoplasias de la Vulva/epidemiología , Adulto , Anciano , Estudios de Casos y Controles , Intervalos de Confianza , Femenino , Humanos , Incidencia , Persona de Mediana Edad , Oportunidad Relativa , Sistema de Registros , Estudios Retrospectivos , Medición de Riesgo , Neoplasias de la Vulva/patología
6.
Obstet Gynecol ; 96(1): 18-22, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10862835

RESUMEN

OBJECTIVE: To compare the severity of pelvic organ prolapse between examinations performed in dorsal lithotomy position and examinations performed upright in a birthing chair using the Pelvic Organ Prolapse Quantification System (POPQ). METHODS: One hundred eighty-nine consecutive women were evaluated between April 1997 and September 1998. All women were examined in the dorsal lithotomy position and in a birthing chair at a 45 degrees angle. Degree of pelvic organ prolapse was assessed using the POPQ. RESULTS: When examined upright, 133 patients (70%) had the same stage of prolapse, whereas 49 (26%) had a higher stage and seven (4%) had a lower stage. Of patients who were stage 0 or I when examined in lithotomy position, 23 (36%) were stage II or greater when examined upright. Similarly, of patients who were stage II in lithotomy, 17 (23%) were stage III or higher when examined upright. There was a statistically significant increase in the degree of prolapse at all the POPQ measurements (P <.05 for each point), except for measurement of total vaginal length. Forty-eight percent of patients had at least one measurement increase by 2 cm or more when examined upright. Logistic regression identified no patient characteristics that were independently associated with a significant increase in stage or POPQ values with change in examination position. CONCLUSION: The degree of pelvic organ prolapse assessed with the patient in the lithotomy position correlates well with assessment performed upright; however, overall there is a higher degree of prolapse with upright examination.


Asunto(s)
Examen Físico , Prolapso Uterino/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Modelos Logísticos , Persona de Mediana Edad
7.
Obstet Gynecol ; 95(6 Pt 1): 931-5, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10831995

RESUMEN

OBJECTIVE: To describe trends in pessary use for pelvic organ prolapse. METHODS: An anonymous survey administered to the membership of the American Urogynecologic Society covered indications, management, and choice of pessary for specific support defects. RESULTS: The response rate was 48% (359 of 748). Two hundred fifty surveys were received at the scientific meeting and 109 were returned by mail. Seventy-seven percent used pessaries as first-line therapy for prolapse, while 12% reserved pessaries for women who were not surgical candidates. With respect to specific support defects, 89% used a pessary for anterior defects, 60% for posterior defects, 74% for apical defects, and 76% for complete procidentia. Twenty-two percent used the same pessary, usually a ring pessary, for all support defects. In the 78% who tailored the pessary to the defect, support pessaries were more common for anterior (ring) and apical defects (ring), while space-filling pessaries were more common for posterior defects (donut) and complete procidentia (Gellhorn). Less than half considered a prior hysterectomy or sexual activity contraindications for a pessary, while 64% considered hypoestrogenism a contraindication. Forty-four percent used a different pessary for women with a prior hysterectomy and 59% for women with a weak pelvic diaphragm. Ninety-two percent of physicians believed that pessaries relieve symptoms associated with pelvic organ prolapse, while 48% felt that pessaries also had therapeutic benefit in addition to relieving symptoms. CONCLUSION: While there are identifiable trends in pessary use, there is no clear consensus regarding the indications for support pessaries compared with space-filling pessaries, or the use of a single pessary for all support defects compared with tailoring the pessary to the specific defect. Randomized clinical trials are needed to define optimal pessary use.


Asunto(s)
Pesarios/estadística & datos numéricos , Pautas de la Práctica en Medicina , Prolapso Uterino/terapia , Adulto , Diseño de Equipo , Femenino , Encuestas de Atención de la Salud , Humanos , Masculino
8.
Obstet Gynecol ; 97(5 Pt 1): 685-92, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11339916

RESUMEN

OBJECTIVE: To evaluate the cost-effectiveness of routine cystoscopy at the time of abdominal, vaginal, and laparoscopically assisted vaginal hysterectomy in terms of cost per ureteral injury identified and treated. METHODS: Using a hospital-based perspective, a decision-analysis model was constructed to estimate the outcomes and costs of cystoscopy or no cystoscopy at the time of abdominal hysterectomy. A similar model was constructed for vaginal and laparoscopically assisted vaginal hysterectomy to account for the cost of conversion to laparotomy. Cost estimates were based on estimated costs of Duke University Medical Center and from average Medicare reimbursements for similar Diagnostic Related Groups from the Health Care Financing Administration. The incidence of ureteral injury was obtained from a review of the literature. Sensitivity analyses were performed for the following variables: ureteral injury rate, silent ureteral injury rate, cost of cystoscopy, and cost of therapeutic interventions. We assumed a silent renal death rate of 0%. RESULTS: Routine cystoscopy at abdominal hysterectomy was cost-saving above a threshold ureteral injury rate of 1.5%. At a ureteral injury rate of 0.2%, the marginal increase in the cost of routine intraoperative cystoscopy was $108 per abdominal hysterectomy, with an associated cost of $54,000 per ureteral injury identified. In comparison, at a ureteral injury rate of 2%, routine cystoscopy gave a marginal cost savings of $44 per hysterectomy, with a cost savings of $2200 per ureteral injury identified intraoperatively. At the baseline ureteral injury rate of 0.5%, routine cystoscopy had a marginally increased cost of $83 per hysterectomy, with an incremental cost-effectiveness of $16,600 spent per ureteral injury identified. The model constructed for vaginal hysterectomy and laparoscopically assisted vaginal hysterectomy yielded a threshold ureteral injury rate of 2%, above which routine cystoscopy was cost-saving. In both models, the incidence of ureteral injury and the cost of readmission were the two variables with the greatest influence on cost-effectiveness. CONCLUSION: The cost-effectiveness of routine intraoperative cystoscopy depends on the rate of ureteral injury independent of the route of hysterectomy. If that rate exceeds 1.5% for abdominal hysterectomy and 2% for vaginal or laparoscopically assisted vaginal hysterectomy, then routine cystoscopy is cost-effective.


Asunto(s)
Cistoscopía/economía , Costos de la Atención en Salud , Histerectomía/efectos adversos , Histerectomía/métodos , Uréter/lesiones , Enfermedades Ureterales/diagnóstico , Análisis Costo-Beneficio , Cistoscopía/métodos , Técnicas de Apoyo para la Decisión , Femenino , Humanos , Histerectomía/economía , Histerectomía Vaginal/efectos adversos , Histerectomía Vaginal/economía , Histerectomía Vaginal/métodos , Histeroscopía/efectos adversos , Histeroscopía/economía , Histeroscopía/métodos , Complicaciones Intraoperatorias/diagnóstico , Complicaciones Intraoperatorias/prevención & control , Monitoreo Intraoperatorio/métodos , North Carolina , Sensibilidad y Especificidad , Enfermedades Ureterales/etiología
9.
J Am Coll Surg ; 192(4): 492-7, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11294406

RESUMEN

BACKGROUND: Anatomic instruction during preclinical years of medical school has been in decline recently. There is evidence that residents already lose a considerable portion of basic anatomic knowledge in the transition from student to clinician, and this deficit is even more dramatic in residents who start their training with a decreased understanding of anatomy. We questioned whether anatomy could be adequately retaught to new residents as surgical anatomy. In an effort to address this deficiency, we developed a program to teach pelvic anatomy in fresh cadavers using a laparoscopic approach. The purpose of this investigation is to determine if such a program is effective in enhancing residents' pelvic anatomy comprehension. STUDY DESIGN: An obstetrics and gynecology residency was divided into intervention (n = 15) and control (n = 13) groups. The intervention was a 4-hour laparoscopic dissection in a fresh cadaver. Outcomes measures included a multiple-choice test, practical exam, faculty evaluation, and satisfaction assessment. The faculty evaluation and satisfaction assessment used a visual analog scale. Univarate and nonparametric analysis were used when appropriate. RESULTS: Initial test scores (p = 0.32), faculty evaluations (p = 0.25), and satisfaction scores (p = 0.17) were similar. Both groups improved their anatomic knowledge based on test scores (p = 0.004) and faculty evaluations (p < 0.001), and final test scores were not significantly different (p = 0.19). Data measured on a 10-cm visual analog scale suggested higher faculty evaluations in the intervention group (14mm versus 10.3mm, (p = 0.23). Similarly there were higher scores on the cadaver test in the intervention group (65% versus 50%), (p = 0.13). The intervention group was significantly more satisfied with their anatomic training (16.1 mm versus-10.1 mm, p = 0.001). CONCLUSIONS: This study did not have sufficient power to demonstrate that a single laparoscopic cadaveric dissection improves cognitive measures of anatomic perception, but suggested that it improves spatial perception of anatomy and is perceived by residents to be a valuable educational approach.


Asunto(s)
Anatomía/educación , Cadáver , Disección , Educación de Postgrado en Medicina/métodos , Ginecología/educación , Laparoscopía , Procedimientos Quirúrgicos Obstétricos , Obstetricia/educación , Pelvis/anatomía & histología , Actitud del Personal de Salud , Competencia Clínica/normas , Disección/métodos , Docentes Médicos , Femenino , Humanos , Laparoscopía/métodos , Cuerpo Médico de Hospitales/educación , Cuerpo Médico de Hospitales/psicología , Procedimientos Quirúrgicos Obstétricos/métodos , Evaluación de Programas y Proyectos de Salud
10.
J Agric Food Chem ; 48(10): 4460-2, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11052684

RESUMEN

In this study, the contamination by chloroparaffin of Sicilian and Calabrian citrus essential oils, produced in the crop years 1994-1996, was investigated. The analyses were carried out on 102 lemon oils, 98 orange oils, and 96 mandarin oils, using a dual-channel GC-ECD. It was found that 53% of lemon oil, 33% of orange oil, and 38% of mandarin oil samples were contaminated. The mean contamination levels were 7.1 ppm (lemon), 2.5 ppm (orange), and 5.3 ppm (mandarin). The highest concentration of chloroparaffin found was 60 ppm in a lemon oil sample.


Asunto(s)
Citrus/química , Contaminación de Alimentos/análisis , Aceites Volátiles/química , Parafina/análogos & derivados , Cromatografía de Gases , Electroquímica , Italia , Parafina/química
11.
Obstet Gynecol Clin North Am ; 25(4): 849-65, vii, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9921560

RESUMEN

In the 50 years since pelvic muscle exercises were introduced for the nonsurgical management of pelvic floor dysfunction related to parturition, a variety of approaches have been introduced and the scope of indications has grown. This article describes the evaluation of patients with pelvic floor complaints, discusses additional techniques for performing pelvic muscle exercises including biofeedback and electrical stimulation, details a comprehensive educational program, and examines the literature on the use of pelvic muscle exercises for the treatment of stress and urge urinary incontinence.


Asunto(s)
Enfermedades Urogenitales Femeninas/rehabilitación , Diafragma Pélvico , Incontinencia Urinaria/rehabilitación , Biorretroalimentación Psicológica , Terapia por Estimulación Eléctrica , Terapia por Ejercicio , Femenino , Enfermedades Urogenitales Femeninas/diagnóstico , Humanos , Pesarios , Incontinencia Urinaria/diagnóstico
12.
Biomed Mater Eng ; 14(3): 251-61, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15299237

RESUMEN

The significant wear of the UHMWPE bearings of explanted knee prostheses is produced mainly by micrometric debris ("third-body" wear) that diffuse toward the mobile metal-polymer interface. Here debris is crushed during the movement producing scratches in the metal and in the polymeric surfaces. Mechanical stress and the biological effects change the physical polymeric properties. In order to evaluate the area of UHMWE bearings submitted to high load stresses, in this work physical investigations are performed on the explanted knee prosthesis. Particularly, the roughness profile analysis (RPA) and the micro-hardness measurements (MHM) resulted suitable for the localisation of the mechanical and biological wear area. In the stressed zone, surface treatments could be applied in order to improve the mechanical resistance of the polymeric material. Particularly, the ion implantation with heavy ions is proposed to enhance the polymeric wear resistance. The Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDX) and Infrared absorption spectroscopy (FTIR) techniques were also applied and results discussed.


Asunto(s)
Materiales Biocompatibles/química , Análisis de Falla de Equipo , Prótesis de la Rodilla , Ensayo de Materiales , Polietilenos/química , Fricción , Dureza , Humanos , Propiedades de Superficie
13.
Pediatr Nurs ; 16(5): 459-62, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-2216569

RESUMEN

To provide more comprehensive follow-up care for low birthweight infants, it is important for nurses to know what concerns mothers of these low birthweight infants commonly experience and how concerns change over time. This descriptive, longitudinal study followed 65 mothers of low birthweight infants from birth until the infant was 6 months adjusted gestational age. Most concerns were raised the week following birth (109) and after infant discharge (72), although from 40 weeks (62) to 6 months (40), the number of concerns raised were fairly consistent. The largest category of concerns was health related (253).


Asunto(s)
Recién Nacido de Bajo Peso , Madres/psicología , Estrés Psicológico/etiología , Femenino , Humanos , Lactante , Recién Nacido , Estudios Longitudinales , Estrés Psicológico/diagnóstico , Estrés Psicológico/enfermería
14.
Indian J Dent Res ; 23(6): 763-9, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23649060

RESUMEN

PURPOSE: The aim of this study is to investigate the presence and the extent of a possible marginal gap after the interposition of a flowable composite between the composite restoration and the dental structures (enamel and cementum). This technique is also used to eliminate the infiltration in a zone of the cavity preparation that is frequently at a risk of secondary decay. MATERIALS AND METHODS: Fifteen human premolars extracted for orthodontic reasons were used for the study. A cavity with mesial and distal margin in enamel and cementum was realized in every tooth. The cavities were then restored with an adhesive system (ScotchBond 3MÔ) and composite (Filtek Supreme 3MÔ); and, a fine layer of flowable composite was applied in the distal margin of each cavity. Scanning electron microscopy (SEM) in secondary electron imaging (S.E.I.) modality was used for the study and identifying the marginal gaps in the composite restorations. Data was investigated on the mesial and distal margin of each cavity at the restoration-enamel interface, and at the restoration-cementum interface. The interfaces were divided in four groups: Group A (enamel/composite); Group B (enamel/flow/composite); Group C (cementum/composite); and, Group D (cementum/flow/composite). RESULTS: By the comparison of the gap's average width found in each group, it is evidenced that the average width of the gap increases when the interface moves from the coronal to the radicular end (Group A 0,1 ± 0,4 µm Vs Group C 12,3 ± 11,6 µm; Group B 0,2 ± 0,8 µm Vs Group D 2,8 ± 6,6 µm). Correlating the measurements of the marginal gap's average width among the Group A and Group B, no significant variations were obtained; and instead, on comparing Group C with Group D, the gap's average width decreases. CONCLUSION: The interposition of a low elastic modulus composite between the adhesive layer and the composite resin allows an improvement of the cementum-restoration interface by the means of a lower shrinkage stress during polymerization.


Asunto(s)
Resinas Compuestas/química , Preparación de la Cavidad Dental/métodos , Cemento Dental/ultraestructura , Esmalte Dental/ultraestructura , Adaptación Marginal Dental , Restauración Dental Permanente/métodos , Módulo de Elasticidad , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Nanocompuestos/química , Polimerizacion , Cementos de Resina/química , Propiedades de Superficie , Viscosidad
15.
J Perinatol ; 30(4): 258-64, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19812591

RESUMEN

OBJECTIVE: To determine whether planned route of delivery leads to differences in neonatal morbidity. STUDY DESIGN: Analysis was based on planned route of delivery, not actual route of delivery. A total of 4048 subjects were divided into two groups: planned vaginal delivery and planned cesarean delivery. Primary outcomes were neonatal intensive care unit (NICU) admission, respiratory morbidity and neurologic morbidity. RESULT: There were 3868 planned vaginal and 180 planned cesarean deliveries. Planned vaginal delivery had decreased NICU admission (P<0.0001), oxygen resuscitation (P=0.001) and jaundice (P<0.0001) but increased meconium passage (P<0.0001) and 1 min Apgar

Asunto(s)
Cesárea/efectos adversos , Parto Obstétrico/efectos adversos , Enfermedades del Recién Nacido/etiología , Adulto , Puntaje de Apgar , Bases de Datos Factuales , Femenino , Edad Gestacional , Humanos , Recién Nacido , Unidades de Cuidado Intensivo Neonatal , Oportunidad Relativa , Participación del Paciente , Embarazo , Estudios Retrospectivos , Adulto Joven
16.
J Biomed Mater Res B Appl Biomater ; 89(1): 55-64, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18777576

RESUMEN

Ultrahigh molecular weight polyethylene (UHMWPE) was modified by a 5-MeV energy electron beam at different temperatures before, during, and after irradiation, both in air and in high vacuum. Wear resistance, hardness, and tensile strength of irradiated polyethylene were compared with those of untreated one. Physical analyses (like infrared spectroscopy and calorimetric analysis) were carried out to investigate about the changes in the material induced by irradiation. Experimental results suggested that structural changes (double bonds, crosslinks, and oxidized species formation) occur in the polymer depending on the environmental conditions of the irradiation. Mechanical behavior is related to the structural modifications. A temperature of 110 degrees C before, during, and after the in vacuum irradiation of UHMWPE produces a high amount of crosslinks and improves polymeric tensile and wear resistance, compared to that of the untreated material.


Asunto(s)
Aire , Polietilenos/efectos de la radiación , Vacio , Ensayo de Materiales , Oxidación-Reducción , Polietilenos/química , Espectroscopía Infrarroja por Transformada de Fourier , Estrés Mecánico , Temperatura , Resistencia a la Tracción
17.
Rev Sci Instrum ; 79(10): 10E912, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19044567

RESUMEN

X-ray framing cameras, employing microchannel plates (MCPs) for detection and signal amplification, play a key role in research in high-energy-density physics. These instruments convert radiographic x-rays into electrons produced by plasma during such experiments into electrons that are amplified in the channels and then detected by a phosphor material. The separation of detection from signal amplification offers potential improvements in sensitivity and noise properties. We have implemented a suspended Au transmission photocathode (160 A thick) on a MCP and are evaluating it using a 1.5 keV Al K alpha x-ray source. We find an approximately twofold increase in the ratio of detected events to incident photons when the photocathode-to-MCP voltage difference is sufficiently large. Our calculations indicate that this increase is probably caused by a combination of signal produced by the photocathode and an increase in the efficiency of detection of x-rays that reach the MCP surface through modification of the local electric field.

18.
Rev Sci Instrum ; 79(10): 10F545, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19044687

RESUMEN

The temporal dispersion of an optical spectrometer has been characterized for a variety of conditions related to optical diagnostics to be fielded at the National Ignition Facility (e.g., full-aperture backscatter station, Thomson scattering). Significant time smear is introduced into these systems by the path length difference through the spectrometer. The temporal resolution is shown to depend only on the order of the grating, wavelength, and the number of grooves illuminated. To enhance the temporal resolution, the spectral gratings can be masked limiting the number of grooves illuminated. Experiments have been conducted to verify these calculations. The size and shape of masks are investigated and correlated with the exact shape of the temporal instrument function, which is required when interpreting temporally resolved data. The experiments used a 300 fs laser pulse and a picosecond optical streak camera to determine the temporal dispersion. This was done for multiple spectral orders, gratings, and optical masks.

19.
Int Urogynecol J Pelvic Floor Dysfunct ; 19(12): 1603-9, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18690402

RESUMEN

The objective was to study the effect of colpocleisis on pelvic support, symptoms, and quality of life and report-associated morbidity and postoperative satisfaction. Women undergoing colpocleisis for treatment of pelvic organ prolapse (POP) were recruited at six centers. Baseline measures included physical examination, responses to the Pelvic Floor Distress Inventory, and Pelvic Floor Impact Questionnaire. Three and 12 months after surgery we repeated baseline measures. Of 152 patients with mean age 79 (+/-6) years, 132 (87%) completed 1 year follow-up. Three and 12 months after surgery, 90/110 (82%) and 75/103 (73%) patients following up had POP stage < or = 1. All pelvic symptom scores and related bother significantly improved at 3 and 12 months, and 125 (95%) patients said they were either 'very satisfied' or 'satisfied' with the outcome of their surgery. Colpocleisis was effective in resolving prolapse and pelvic symptoms and was associated with high patient satisfaction.


Asunto(s)
Procedimientos Quirúrgicos Ginecológicos , Prolapso Uterino/cirugía , Femenino , Indicadores de Salud , Humanos , Satisfacción del Paciente , Estudios Prospectivos , Calidad de Vida , Resultado del Tratamiento , Incontinencia Urinaria/cirugía , Vagina/cirugía
20.
Urology ; 56(6 Suppl 1): 2-8, 2000 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-11114556

RESUMEN

We describe our experience with the use of allograft fascia lata for the treatment of stress urinary incontinence. One hundred and four patients underwent allograft fascia lata pubovaginal slings. Preoperatively, all were evaluated by a detailed urogynecologic evaluation, voiding diary, and pelvic examination. The pubovaginal sling was performed using a 2x15-cm freeze-dried nonirradiated cadaveric fascia lata specimen. Outcome measures were assessed by a urogynecologic questionnaire, pad usage, and disease-specific quality-of-life questionnaires. Eighty-eight percent (91 of 104) responded to a mailed urogynecology and disease-specific quality-of-life questionnaire with an average follow-up period of 19. 4 +/- 10.3 months. The mean preoperative daily pad usage was 4.6 +/- 3.0, postoperatively pad usage was 1.1 +/- 1.4 (P < 0.0001). Urge incontinence resolved in 41% (n = 24) of the 59 patients who complained of this preoperatively. Eighty-seven percent of the responders indicated that urinary incontinence was not substantially affecting their daily life. As in our preliminary report, the use of freeze-dried allograft pubovaginal sling continues to provide good results without adverse outcomes. A prospective, randomized comparison of autologous versus allograft slings and a review of preparation techniques used by tissue banks are needed.


Asunto(s)
Fascia Lata/trasplante , Incontinencia Urinaria de Esfuerzo/cirugía , Anciano , Cadáver , Cistostomía/métodos , Femenino , Estudios de Seguimiento , Liofilización , Humanos , Persona de Mediana Edad , Calidad de Vida , Radiografía , Encuestas y Cuestionarios , Técnicas de Sutura , Resultado del Tratamiento , Vejiga Urinaria/diagnóstico por imagen , Vejiga Urinaria/cirugía , Incontinencia Urinaria de Esfuerzo/diagnóstico , Urodinámica
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