Soft Tip Research Articles

The type of catheter has no impact on the pregnancy rate after intrauterine insemination: a randomized study

This study was done to test the hypothesis that intrauterine insemination (IUI) using a soft-tip catheter results in a higher live birth rate than IUI using a hard-tip catheter. Five hundred and forty patients were randomized into those inseminated with a soft-tip catheter (group 1, n = 267) and those inseminated with a hard-tip catheter (group 2, n = 269). Four patients were excluded. Main outcome measures included pregnancy rate and live birth rate per cycle. Both groups were similar with regard to female age, duration of infertility, ovarian stimulation and sperm quality. No significant differences were observed between group 1 and group 2 regarding clinical pregnancy rate per cycle (20 versus 19%), live birth rate per cycle (15 versus 14%), multiple live birth rate per cycle (4 versus 6%) and multiple live birth per total of live births (5 versus 8%, overall 6%), respectively. Our hypothesis that IUI using a soft tip catheter results in a higher live birth rate per cycle than IUI using a hard-tip catheter was not confirmed in this study. Multiple live birth rate after treatment with low-dose gonadotrophins and IUI can be kept low (6%).

FINITE ELEMENT ANALYSIS AND EXPERIMENTAL EVALUATION OF BIOYIELD PROBES FOR MEASURING APPLE FRUIT FIRMNESS

The bioyield phenomenon occurs during compression of an apple fruit by a mechanical probe, which results in cell failure without tissue rupture. Because of its minimal damage to the fruit, the bioyield phenomenon can be used for nondestructive or minimally destructive evaluation of fruit firmness. The objective of this research was to develop a probe for better measurement of the bioyield point for apple fruit to assess their firmness. The research was based on the premise that the soft-tipped probe would produce constant contact and a uniform pressure distribution over the contact area of the fruit and thus enhance the detection of the bioyield point. The finite element method was used to analyze the contact stress distribution in the apple fruit resulting from the compression of soft bioyield probes of different sizes, thicknesses, and elastic moduli. The modeling results showed that to achieve uniform contact pressure, the bioyield probe should have a soft tip with an elastic modulus comparable to or less than that of the fruit and a thickness greater than 2 mm. Six bioyield probes, along with the standard destructive Magness-Taylor (MT) firmness tester, were tested on four apple cultivars (‘Gala,’ ‘Golden Delicious,’ ‘Fuji,’ and ‘Red Delicious’). Probe size (between 6.4 mm and 11.1 mm) did not affect the correlation between force at the bioyield point and MT firmness. The probe with a 1.6 mm thick tip, which was undesirable based on the finite element modeling, had a high missing rate (13%) of detecting the bioyield point, compared to that (2%) for the other five probes with thicker soft tips. The 6.4 mm probe with a 3.2 mm thick rubber tip and an elastic modulus of 3.27 MPa had a good correlation (r = 0.828) with MT firmness measurement. Since the smaller probe causes minimal damage to the fruit, it is a better choice for the bioyield measurement.

Unusual Complication With A Cohen Flexitip Endobronchial Blocker

DEAR EDITOR The above complication occurred while inserting Cohen Flexitip endobronchial blocker ( 1). The most important feature of the blocker is its flexible soft tip that allows to direct it in the desired bronchus. The blocker contains a lumen that allows suctioning of the lung to facilitate deflation, suctioning of secretion and insufflation of oxygen

In‐utero intervention for hypoplastic left heart syndrome — a perinatologist's perspective

.Today,whenHLHSisdiagnosedinthenewborn,or suspected by prenatal ultrasound studies, surgicalinterventions typically take one of two directions – eitherthe multistaged reconstruction pioneered by Norwood toenable single ventricle survival or cardiac transplantation.Compassionate care, although increasingly controversial,remains an option in some centers. Although increasingsurvival rates following both multi-staged surgery ortransplant are being reported, the nature of theseinterventions is such that these children remain at lifelongrisk for cardiac and neurologic morbidity.Consideration of HLHS as a candidate for

Evaluation of bioavailability of nitric oxide in coronary circulation by direct measurement of plasma nitric oxide concentration

Although bioavailability of NO in the coronary circulation is commonly evaluated by acetylcholine (ACh)-induced vasodilation, a change in plasma NO concentration and its relation to the flow response after injection of ACh are still unknown. Thus, we directly measured the concentration of NO in the coronary sinus by using a catheter-type NO sensor for coronary sinus. An NO-sensitive sensor was located and fixed in a 4-Fr catheter with a soft tip for protection of vascular wall. After calibration with an NO-saturated pure water, the catheter-type NO sensor was located in the coronary sinus in anesthetized dogs. The coronary flow velocity (CFV) was measured with a Doppler guide wire. Intracoronary injection of ACh (0.4 and 1.0 microg/kg) increased plasma NO concentration in a dose-dependent manner (3-10 nM). Although ACh increased CFV by 95%, there was no significant difference between the two ACh doses. After ACh, the peak value of plasma NO concentration was observed significantly later than CFV. N(G)-methyl-L-arginine (NO synthase inhibitor) decreased basal NO concentration by 3 nM and suppressed the ACh-induced NO synthesis with no significant change in average peak velocity. We conclude that production of NO in the coronary circulation can be evaluated in the coronary sinus. Although ACh increases both CFV and NO concentration, CFV dose not reflect NO concentration in terms of magnitude and time course. Direct measurement of plasma NO concentration by the catheter-type NO sensor is useful to evaluate bioavailability of NO in the coronary circulation.

MODELING AND ANALYSIS OF NANOTIPS FOR THERMOELECTRIC COOLERS

Thermoelectric cooling system can be used in many applications. The properties of structured point contact at the cold end affect the performance of thermoelectric cooling. The performance of metal point junctions as a function of tip radius show that the smaller the tip radius, the better the figure of merit. This paper presents the modeling and analysis of the nanotips. Each nanotip will have to carry some fraction of the weight of the thermoelectric material and the silicon slabs. The small apical area of each nanotip causes a very high pressure build up. The device may be loaded externally to ensure proper nanotip and thermoelectric material contact. A deformation of approximately 10 to 15 nm would be ideal. Finite Element Analysis (FEA) needed to be applied to determine how tall each nanotip must be to maximize soft and hard tip contacts. FEA was also needed to approximate the amount of external loading that will be necessary. ANSYS software was used in the modeling and analysis of the nanotips.

Complications Associated With Isotretinoin Use After Rhinoplasty

This study aimed to evaluate the association between the postoperative use of isotretinoin and the formation of nasal tip deformities after rhinoplasty. A retrospective study investigated a case series of patients who presented with nasal tip deformities subsequent to the use of isotretinoin after rhinoplasty. Patients who had taken isotretinoin after rhinoplasty were identified from a single surgeon's case log. Clinic charts and operative reports were reviewed. Predisposing factors and time intervals to complications were identified. Three patients were found to have undergone isotretinoin therapy after rhinoplasty. Nasal tip deformities included bossa formation, asymmetry, and prominence of a composite graft. All three patients required subsequent procedures to repair soft tissue nasal tip deformities. In all three cases, isotretinoin was started within 2 years of the primary rhinoplasty. The nasal tip deformities were first observed within 6 months after isotretinoin was started. Three cases are described in which postoperative use of isotretinoin was associated with nasal tip deformities after rhinoplasty. Further studies are needed to investigate this possible causative relationship and to describe the risks involved.

A case of normal ropivacaine concentration causing grand mal seizure after epidural injection

A case of normal ropivacaine concentration causing grand mal seizure after epidural injection

Effects of Isoflurane on gastrointestinal motility after brief exposure in rats

In pre-clinical studies, investigation of oral formulations often necessitates the use of general anesthesia to facilitate deposition of material directly into the stomach. Since the effectiveness of intestinal drug absorption is dependent on gastric emptying (GE) and intestinal motility, drugs that influence either will also influence drug absorption. This study investigated gastrointestinal motility in rats after brief exposure to Isoflurane (ISO) general anesthesia for orogastric gavage. The use of metochlopramide was also evaluated. Twenty-five fasted rats were induced with brief ISO anesthesia (<6 min). Rats were gavaged a gelatin capsule (8 mm (L) × 2.0 mm (o.d.)) containing 9 mg of activated charcoal powder (gastrointestinal marker) and rapidly recovered. Gavage was performed using a 15 cm feeding device with a soft hollow tip to hold the capsule. Study included three groups (60 and 120 min recovery, metochlopramide pre-treatment with 60 min recovery) and control. Animals were sacrificed for exposure and examination of the gastrointestinal tract following the allocated recovery period. Gastrointestinal transit of charcoal was reduced approximately 50% 120 min after brief ISO anesthesia. Metochlopramide pre-treatment did not increase gastrointestinal propulsion despite increased GE. These data warrant consideration in intestinal drug absorption studies where ISO is the anesthetic of choice.

A NEW BIOYIELD TESTER FOR MEASURING APPLE FRUIT FIRMNESS

The objective of this research was to evaluate a newly developed bioyield tester for measuring fruit firmness andits measurement variability within individual fruit. The specially designed soft tip bioyield probe was coupled to a handhelddigital force gauge that was mounted on a tabletop motor-driven stand. Bioyield force (or Fbyst = force to cause bioyield bythe soft tip probe) and Magness-Taylor (MT) firmness were measured on Delicious and Golden Delicious apples underdifferent storage conditions and/or treatments. The correlation between MT firmness and Fbyst ranged from 0.62 to 0.81 witha standard error between 5.2 N and 6.7 N. Bioyield force decreased at about the same rate as that for MT firmness when appleswere stored in refrigerated air at 5.C. When fruits were kept at room temperature (24.C), the percent decline in Fbyst overthe test time period was less than that in MT firmness. Bioyield force measurements within individual apples were 42.6% to46.8% more variable than MT firmness, as measured by the coefficient of variation. Since the bioyield tester does not degradeapple fruit, it will be useful for measuring and monitoring fruit firmness during growth, harvest, and postharvest operations.

Correlation of domain pattern and high-frequency response in pole-tip of inductive thin film head

The high frequency response of the soft magnetic pole tip in the thin film inductive head is crucial for the noise analysis of computer hard disk. A micromagnetic model is established in a mesoscopic soft magnetic thin film to analyze the domain pattern as well as the initial permeability in a wide frequency range from 10MHz to 18GHz. The simulated domain patterns in the pole tip, a vortex- and ladder-type, are chosen as the initial conditions for the high-frequency response studies. The scaling law of the permeability is analyzed at different amplitudes of the alternating external magnetic field. It is found that in the ladder-type domains the high frequency response is much better than that in the vortex-type domains, which agrees with experiment. A simplified explanation of the simulation result is discussed based on the analysis of the nonlinear Landau–Liftshitz equation.

Should we cross the valve: the risk of retrograde catheterization of the left ventricle in patients with aortic stenosis

A 67-year-old man is referred to your cardiology clinic complaining of worsening angina and dyspnea on exertion. Physical examination reveals a harsh grade IV/VI late-peaking crescendo-decresendo systolic murmur, loudest at the upper sternal border. The aortic closure sound is diminished. Echocardiography demonstrates left ventricular hypertrophy, an ejection fraction of 50%, no evidence of mitral regurgitation, and severe aortic stenosis (AS) with a peak aortic gradient of 4.8 m/s (92 mm Hg) and a mean aortic gradient of 55 mm Hg. You schedule him for coronary angiography but wonder whether you should reevaluate his aortic valve gradient invasively. Combining the keywords "aortic valve stenosis" and "heart catheterization/adverse effects," you find 72 articles. From these you choose the following: Omran H, Schmidt H, Hackenbroch M, et al. Silent and apparent cerebral embolism after retrograde catheterization of the aortic valve in valvular stenosis: a prospective randomized study. Lancet 2003;361:1241-6. What is the stroke risk of retrograde catheterization of the aortic valve in patients with AS? The study was prospective and randomized; unblinded treatment but with blinded assessment of outcomes. The study was conducted at a single center in Bonn, Germany. A total of 152 patients with known or suspected AS undergoing cardiac catheterization were randomized to catheterization with or without retrograde passage of the aortic valve in a 2:1 randomization format. Patients underwent brain magnetic resonance imaging (MRI) the day before and within 48 hours after cardiac catheterization. Patients with unclear echo findings or contraindications to MRI or transesophageal echocardiography were excluded. There were no significant baseline differences between the 2 groups: mean age 70.5 years, left ventricular ejection fraction 62%, and mean aortic valve gradient 51 mm Hg. All patients were evaluated in the groups to which they had been randomized and, other than the experimental intervention, the 2 groups were treated similarly (with the exception of the administration of 5000 units of intravenous heparin to the group receiving retrograde aortic catheterization). A control group of 32 patients without aortic valvular stenosis was evaluated as well. The intervention consisted of retrograde passage of the aortic valve for the purpose of obtaining an invasive aortic valve pressure gradient. The main outcome measures were acute cerebral embolic events, defined by MRI findings within 48 hours after catheterization (as compared to precatheterization MRI) and by clinical examination. Twenty-two of 101 patients (22%) assigned to retrograde catheterization developed new focal MRI abnormalities consistent with acute cerebral embolic events. Three of these patients (3%) demonstrated clinically apparent neurologic deficits. None of the patients who did not undergo retrograde catheterization--and none of the control patients--had MRI or clinical evidence of cerebral embolism.

Investigation of a magnetic flux-guide for a HTS scanning superconducting quantuminterference device microscope

A magnetic flux-guide in the form of a sharp needle is known to enhance the spatialresolution of the scanning SQUID microscope. We investigated the properties ofa soft ferromagnetic tip as a flux-guide by measuring the local field of the tipend. The effects of the flux-guide, such as the transmission of a magnetic signal,length dependence, and nonlinear distortion, were observed. We also present thedesign and construction of a HTS scanning SQUID microscope with a flux-guideand a planar gradiometer. The gradiometer with a flux-guide is an appropriatesolution for improving the performance of the scanning SQUID microscope with aflux-guide as regards the prevention of external field noise without magnetic shields.

Can soft tip epidural catheter prevent minor complications?

Can soft tip epidural catheter prevent minor complications?

Development of a novel nasal lavage device to obtain nasopharyngeal mucus samples for viral identificaion in infancy

Rationale To develop a patient-acceptable technique for nasal lavage (NL) during infancy to identify viral pathogens producing wheezing illnesses. Methods In prospective epidemiologic evaluations, a major drawback to the standard Dacron tipped swab method used for the procurement of nasal mucus samples for viral culture is the development of patient and parental intolerance for the procedure. Therefore, we developed a novel device for NL by creating a soft tip to insert into the child's nares, a syringe to aggressively wash the membrane with saline (thus dislodging cells), and a means to aspirate and collect the sample. Results Using this device during infancy, overall positive viral identification by culture and PCR was obtained in 72% (414/578) samples in children with symptom scores of >=5. Of these, viral recovery rates were highest 78% (69/88) of children with significant (score >10) lower respiratory tract illnesses and in children with scores of 5-10, virus was detected in 70% (345/490) of the samples. With minimal illness (score 1-4), virus was detected in 47% (97/215) of the samples and detected 10% (89/893) of the time in infants with no symptoms. Familial acceptance of the procedure was excellent, with many parents requesting to keep the device to use for clearance of upper respiratory tract secretions. Conclusions In a seven year prospective birth cohort study (COAST) to evaluate genetic and environmental factors underlying asthma inception, the development and use of this nasal lavage device, instead of the nasal swab, has facilitated repetitive specimen collection and viral identification without impairing subject retention.

AFM ANALYSIS OF QUANTUM DOT STRUCTURES INDUCED BY ION SPUTTERING WITH DIFFERENT TIPS

With tips of different hardness, we analyzed the effect of the hardness and shape of the actual AFM tip on the measurement of the best GaSb quantum dot (QD) structures induced by low energy Ar + sputtering. The comparison indicated that the complete information on the detailed dot shape and order structure can be determined with the hard and good tip, while with the soft or worn tip some information on the dot height and shape cannot be obtained. Our results suggest that, in order to obtain the complete surface information, the high hardness and good AFM tip should be used for semiconductor QD structures.

Selective Bronchography

Selective Bronchography

Continuous outflow devices for macular translocation with 360-degree retinotomy

Purpose Separation of the retina from retinal pigment epithelium is the most difficult step in macular translocation surgery. To complete this critical step, we have developed two specially designed continuous outflow needles, a rigid needle for creating retinal detachment and a liquid perfluorocarbon injection needle with a soft tip. Design Experimental study, new instrument development. Methods To permit continuous outflow during separation of the retina from the retinal pigment epithelium, the shaft of the continuous outflow needle is smaller than 20 gauge in diameter to allow continuous flow of fluid from the vitreous cavity. Results These instruments have been used successfully in 54 eyes that underwent macular translocation with 360-degree retinotomy. The rigid needle creates safe retinal detachment by keeping intraocular pressure lower, which is strictly needed for this step. The injection needle facilitates injection of perfluorocarbon liquid while manipulating the retina gently with its soft tip. Conclusion Continuous outflow instruments are useful tools because they facilitate critical steps in the delicate process of macular translocation surgery.

Longitudinal investigation of soft palate and nasopharyngeal airway relations in different rotation types.

The relationship between the soft palate and the nasopharyngeal airway in different mandibular growth rotation models was investigated. A total of 72 lateral cephalograms were obtained three years longitudinally from 24 individuals. The subjects had a mean age of 10.7 +/- 1.2 years and showed a normal (n = 8), posterior (n = 8), and anterior (n = 8) mandibular rotation pattern. Linear and angular measurements of the soft palate and nasopharyngeal airway were recorded by using PORDIOS computer program and were examined by means of descriptive statistics and paired t-tests. A linear increase in the soft palate length (SPL) was observed in all groups, with the posterior mandibular rotation group showing the largest increase within the observation period (28.56 +/- 4.83 to 34.98 +/- 2.87; P < .01). According to the paired t-test, palatal plane (ANS-PNS)/soft palate tip (SPT) angle showed a statistically significant decrease in the posterior rotation group (P < .01). The ratio between SPL and superior nasopharyngeal space (SPS) did not show a statistically significant difference among the groups. Although various amounts of soft palate and nasopharyngeal airway growth occurred in the different mandibular rotation types, the ratio between SPL and SPS (SPL/SPS), which plays an indispensable role in velopharyngeal functions, did not show a statistically significant difference in the groups. This assured velopharyngeal closure throughout the active growth period.

Evaluation of trajectories and contact pressures for the straight nucleus cochlear implant electrode array — a two-dimensional application of finite element analysis

A two-dimensional (2D) finite element analysis has been used in this study to model the insertion of the Nucleus electrode array with different stiffness properties in order to evaluate the propensity of damage by visualizing the predicted trajectories and by comparing the buckling stresses and the contact pressures at the tip (and its distribution along the length) of the electrode array. Previous temporal bone studies have shown that damage during insertion of an electrode array around the basal turn of the cochlear spiral could be related to the design and the stiffness properties of the electrode array. However, it is difficult to evaluate different designs of electrode arrays purely by experimental methods as the experimental conditions and their results are difficult to reproduce. Three electrode arrays with different mechanical properties, i.e. uniform stiffness, graded stiffness, and a soft tip have been modelled. Buckling stress and contact pressure at the tip of the electrode array were found to be highest for the arrays with uniform stiffness. The contact pressures at the tip of the electrode array appeared strongly influenced by the stiffness profile and were optimal for graded stiffness. The results indicate the importance of the electrode array design and stiffness properties in minimizing trauma. However, there are a number of limitations in the present 2D evaluation which will require further analysis using a three-dimensional model to obtain definitive results.