A comparative study of water perfusion catheters and microtip transducer catheters for urethral pressure measurements

The aim of this study was to compare the maximum urethral closure pressure (MUCP) measures with two different techniques: water perfused catheter and microtip transducer catheters with respect to reproducibility and comparability for urethral pressure measurements. Eighteen women with stress urinary incontinence had repeat static urethral pressure profilometry on a different day using a dual microtip transducer and water perfused catheter (Brown and Wickham). The investigators were blinded to the results of the other. The microtip measurements were taken in the 45° upright sitting position with the patient at rest at a bladder capacity of 250ml using an 8 Fr Gaeltec® double microtip transducer withdrawn at 1mm/s, and the transducer was orientated in the three o'clock position. Three different measures were taken for each patient. Three water perfusion measurements were performed with the patient at rest in the 45° upright position at a bladder capacity of 250ml using an 8 Fr BARD dual lumen catheter withdrawn at 1mm/s. The mean water perfusion MUCP measure was 26.1cm H20, significantly lower than the mean microtip measure of 35.7cm H20. The correlation coefficient comparing each water perfusion measurement with the other water perfusion measures in the same patient was excellent, at 0.95 (p = 0.01). Correlation coefficient comparing each microtip measure with the other microtip measure in the same patient was also good, ranging from 0.70 to 0.80. This study confirms that both water perfusion catheters and microtip transducers have excellent or very good reproducibility with an acceptable intraindividual variation for both method

Porównanie maksymalnego ciśnienia zamknięcia cewki moczowej mierzone cewnikiem typu mikrotip i cewnikiem wypełnionym powietrzem – badanie randomizowane

Background: Measurements of maximum urethral closure pressure (MUCP) are a part of urodynamic investigations preceding an incontinence surgery and a part of urethral function tests. Objectives: The aim of the study was to compare maximum urethral closure pressure determined by a microtip catheter with those measured by an air-charged catheter. Material and methods: A prospective randomized study in a tertiary referral centre. 122 female patients with urodynamic stress incontinence were randomly assigned to have their urethral pressure profi les measured at rest by both microtip and air-charged catheters. Intervention and Measurements: Each patient had three measurements taken by each catheter type. Means of the measurements were compared with regard to correlation and repeatability. For statistical analysis, an approach proposed by Bland-Altman was applied to assess the agreement between the two techniques. Results: Correlation coeffi cient between MUCP by the air-charged and the microtip catheter was r=0.8507(95% CI 0.7928 – 0.8934; pCel: Pomiar maksymalnego ciśnienia zamknięcia cewki moczowej (MUCP) jest częścią badania urodynamicznego poprzedzającego operacyjne leczenie nietrzymania moczu i częścią testow czynnościowych cewki moczowej. Celem pracy było porownanie maksymalnego ciśnienia zamknięcia cewki moczowej zmierzonego przy pomocy cewnika microtip i cewnika wypełnionego powietrzem. Materiał i metoda: Przeprowadzono prospektywne, randomizowane badanie w ośrodku trzeciego stopnia referencyjności. Do badania losowo włączono 122 kobiety z nietrzymaniem moczu, u których wykonywano profi l ciśnień w cewce moczowej w spoczynku przy pomocy zarówno cewnika microtip jak i cewnika wypełnionego powietrzem. Każda pacjentka miała wykonane trzy pomiary przy pomocy obu cewników. Średnie z pomiarów porównano w odniesieniu do korelacji i powtarzalności. Do celów statystycznych użyto metody Bland-Altmana oceniającej zgodność obu technik pomiarów. Wyniki: Współczynnik korelacji pomiędzy MUCP mierzonym cewnikiem powietrznym a cewnikiem microtip wynosił r=0,8507(95% CI 0,7928–0,8934;

Superparamagnetic Poly (3-hydroxybutyrate-co-3 hydroxyvalerate) (PHBV) nanoparticles for biomedical applications

Indexación: ScieloBackground: The progress in material science and the recent advances in biodegradable/biocompatible polymers and magnetic iron oxide nanoparticles have led to develop innovative diagnostic and therapeutic strategies for diseases based on multifunctional nanoparticles, which include contrast medium for magnetic resonance imaging, agent for hyperthermia and nanocarriers for targeted drug delivery. The aim of this work is to synthesize and characterize superparamagnetic iron oxide (magnetite), and to encapsulate them into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles for biomedical applications. Results: The magnetite nanoparticles were confirmed by X-ray diffraction and exhibited a size of 22.3 ± 8.8 nm measured by transmission electron microscopy (TEM). Polymeric PHBV nanoparticles loaded with magnetite (MgNPs) were analyzed using dynamic light scattering and showed a size of 258.6 ± 35.7 nm and a negative zeta potential (-10.8 ± 3.5 mV). The TEM examination of MgNPs exhibited a spherical core-shell structure and the magnetic measurements showed in both, non-encapsulated magnetite and MgNPs, a superparamagnetic performance. Finally, the in vitro studies about the magnetic retention of MgNPs in a segment of small intestine of rats showed an active accumulation in the region of the magnetic field. Conclusions: The results obtained make the MgNPs suitable as potential magnetic resonance imaging contrast agents, also promoting hyperthermia and even as potential nanocarriers for site-specific transport and delivery of drugs. Keywords: hyperthermia, magnetic resonance image (MRI), magnetite, PHBV, polymeric nanoparticles.http://ref.scielo.org/cxt57

Electrical transport and low-temperature scanning tunneling microscopy of microsoldered graphene

Using the recently developed technique of microsoldering, we perform a systematic transport study of the influence of PMMA on graphene flakes revealing a doping effect of up to 3.8x10^12 1/cm^2, but a negligible influence on mobility and gate voltage induced hysteresis. Moreover, we show that the microsoldered graphene is free of contamination and exhibits a very similar intrinsic rippling as has been found for lithographically contacted flakes. Finally, we demonstrate a current induced closing of the previously found phonon gap appearing in scanning tunneling spectroscopy experiments, strongly non-linear features at higher bias probably caused by vibrations of the flake and a B-field induced double peak attributed to the 0.Landau level of graphene.Comment: 8 pages, 3 figure

A low-power/low-voltage CMOS wireless interface at 5.7 GHz with dry electrodes for cognitive networks

This paper describes a low-power/low-voltage CMOS wireless interface (CMOS-WiI) at 5.7 GHz with dry electrodes for congnitive networks. The electrodes are 4 x 4 microtip arrays and acquire electroencephalogram (EEG) signals in key- points for processing. The CMOS-WiI was fabricated in a UMC 0.18 µm RF CMOS process and its total power consumption is 23mW with a voltage-supply of only 1.5 V. The carrier frequency is digitally selectable and it can be one of 16 possible values in the range 5.42–5.83 GHz, with 27.12 MHz steps. These multiple carriers allow a better spectrum allocation as well as the acquisition, processing and transmission of high-quality EEG signals from 16 electrode arrays. The microtips array was fabricated through bulk micromachining of a -type silicon substrate in a potassium hydroxide solution and avoids long subject preparations for EEG data acquisition. The reactive sputtering of iridium dioxide (IrO) on the surface of the array guarantees its biocompatibility. The fabrication process was trimmed in a way that each microtip presents solid angles of 54.7 , a width in the range 150–200 µm, a height of 100–200 µm, and a microtip interspacing of 2 µm. The microtips array coated with IrO together with the CMOS-WiI permit the remote monitoring of EEG signals from freely-moving subjects

Effects of O2, H2, and N2 gases on the field emission properties of diamond-coated microtips

This article discusses the effects of O2, H2, and N2 gases on the field emission properties of diamond-coated microtips