Salvage of exhausted neck access using a novel inside‐out device in dialysis‐dependent patients

Chronic central venous occlusion represents a challenge for upper body central dialysis access for both surgical and endovascular interventions. The Surfacer (Surfacer Inside‐Out Access Catheter System) is a novel technique that offers a device‐based solution over various physician‐modified techniques in salvaging exhausted right‐sided neck veins for catheter placement. We report a retrospective series of four cases in which this system is used to gain upper body venous access from a single center in Singapore. This report seeks to integrate the understanding of the technical aspects of a new inside‐out device and its utility in recanalization of occluded right‐sided neck veins as it relates to Asian patients.     

Fatigue behavior of Ti-6Al-4V cellular structures fabricated by additive manufacturing technique

Porous titanium and its alloys have been considered as promising replacement for dense implants, as they possess low elastic modulus comparable to that of compact human bones and are capable of providing space for in-growth of bony tissues to achieve a better fixation. Recently, the additive manufacturing (AM) method has been successfully applied to the fabrication of Ti-6Al-4V cellular meshes and foams. Comparing to traditional fabrication methods, the AM method offers advantages of accurate control of complex cell shapes and internal pore architectures, thus attracting extensive attention. Considering the long-term safety in the human body, the metallic cellular structures should possess high fatigue strength. In this paper, the recent progress on the fatigue properties of Ti-6Al-4V cellular structures fabricated by the AM technique is reviewed. The various design factors including cell shapes, surface properties, post treatments and graded porosity distribution affecting the fatigue properties of additive manufactured Ti-6Al-4V cellular structures were introduced and future development trends were also discussed.     

Frequency-agile bandpass filter for direct detection lidar receivers

We discuss the development of a frequency-agile receiver for CO(2) laser-based differential absorption lidar (DIAL) systems. The receiver is based on the insertion of a low-order tunable etalon into the detector field of view. The incorporation of the etalon into the receiver reduces system noise by decreasing the instantaneous spectral bandwidth of the IR detector to a narrow wavelength range centered on the transmitted CO(2) laser line, thereby improving the overall D* of the detection system. A consideration of overall lidar system performance results in a projected factor of a 2-7 reduction in detector system noise, depending on the characteristics of the environment being probed. These improvements can play a key role in extending the ability of DIAL systems to monitor chemical releases from long standoff distances.     

The impact of domestic violence on women''s mental health

Broiler chicks were spray treated on the day of hatch with titrated dosages (10(6), 10(7), or 10(8) anaerobic CFU) of a characterized competitive exclusion culture (CF3) and challenged orally on day 3 with 10(4) CFU of Salmonella typhimurium. On day 10, cecal contents from control and CF3-treated chicks were cultured for S. typhimurium to determine the minimal efficacious dosage of the CF3 culture. The experiment was repeated in three replicated trials. Resistance to Salmonella cecal colonization was dosage related and progressively enhanced at the 10(7)- and 10(8)-CFU dosages compared with the 10(6)-CFU dosage. The 10(7)-CFU dosage was selected as the minimal effective dosage and evaluated for efficacy during a 43-day broiler growout study. Six hundred broilers were spray treated on the day of hatch and compared with 600 controls. One-half of the control and CF3-treated birds were challenged orally on day 3 with 10(4) CFU of S. typhimurium and designated "seeders." The remaining unchallenged birds were designated "contacts." Compared with the controls, the recovery of Salmonella cells from the ceca of the CF3-treated broilers was significantly decreased (P < 0.01) in the challenged seeders on days 21 and 43 of growout. Salmonella contamination of floor pen litter was significantly reduced (P < 0.05) in pens of CF3-treated birds compared with controls. The transmission of Salmonella cells from seeder to contact birds in the same pens was decreased significantly (P < 0.01). The results indicated that treatment of broiler chicks on the day of hatch with the 10(7)-CFU dosage of CF3 culture effectively increased resistance to S. typhimurium challenge during growout to market age.     

Improvement of CT-based treatment-planning models of abdominal targets using static exhale imaging

PURPOSE: CT-based models of the patient that do not account for the motion of ventilation may not accurately predict the shape and position of critical abdominal structures. Respiratory gating technology for imaging and treatment is not yet widely available. The purpose of the current study is to explore an intermediate step to improve the veracity of the patient model and reduce the treated volume by acquiring the CT data with the patients holding their breath at normal exhale. METHODS AND MATERIALS: The ventilatory time courses of diaphragm movement for 15 patients (with no special breathing instructions) were measured using digitized movies from the fluoroscope during simulation. A subsequent clinical protocol was developed for treatment based on exhale CT models. CT scans (typically 3.5-mm slice thickness) were acquired at normal exhale using a spiral scanner. The scan volume was divided into two to three segments, to allow the patient to breathe in between. Margins were placed about intrahepatic target volumes based on the ventilatory excursion inferior to the target, and on only the reproducibility of exhale position superior to the target. RESULTS: The average patient's diaphragm remained within 25% of the range of ventilatory excursion from the average exhale position for 42% of the typical breathing cycle, and within 25% of the range from the average inhale position for 15% of the cycle. The reproducibility of exhale position over multiple breathing cycles was 0.9 mm (2sigma), as opposed to 2.6 mm for inhale. Combining the variation of exhale position and the uncertainty in diaphragm position from CT slices led to typical margins of 10 mm superior to the target, and 19 mm inferior to the target, compared to margins of 19 mm in both directions under our prior protocol of margins based on free-breathing CT studies. For a typical intrahepatic target, these smaller volumes resulted in a 3.6% reduction in Veff for the liver. Analysis of portal films shows proper target coverage for patients treated based on exhale modeled plans. CONCLUSIONS: Modeling abdominal treatments at exhale, while not realizing all the gains of gated treatments, provides an immediate reduction in the volume of normal tissue treated, and improved reliability of patient data for NTCP modeling, when compared to current "free breathing" CT models of patients.     

Comparing Detection Methods For Software Requirements Inspections: A Replication Using Professional Subjects

Software requirements specifications (SRS) are often validated manually. One such process is inspection, in which several reviewers independently analyze all or part of the specification and search for faults. These faults are then collected at a meeting of the reviewers and author(s).Usually, reviewers use Ad Hoc or Checklist methods to uncover faults. These methods force all reviewers to rely on nonsystematic techniques to search for a wide variety of faults. We hypothesize that a Scenario-based method, in which each reviewer uses different, systematic techniques to search for different, specific classes of faults, will have a significantly higher success rate.In previous work we evaluated this hypothesis using 48 graduate students in computer science as subjects.We now have replicated this experiment using 18 professional developers from Lucent Technologies as subjects. Our goals were to (1) extend the external credibility of our results by studying professional developers, and to (2) compare the performances of professionals with that of the graduate students to better understand how generalizable the results of the less expensive student experiments were.For each inspection we performed four measurements: (1) individual fault detection rate, (2) team fault detection rate, (3) percentage of faults first identified at the collection meeting (meeting gain rate), and (4) percentage of faults first identified by an individual, but never reported at the collection meeting (meeting loss rate).For both the professionals and the students the experimental results are that (1) the Scenario method had a higher fault detection rate than either Ad Hoc or Checklist methods, (2) Checklist reviewers were no more effective than Ad Hoc reviewers, (3) Collection meetings produced no net improvement in the fault, and detection rate—meeting gains were offset by meeting losses,Finally, although specific measures differed between the professional and student populations, the outcomes of almost all statistical tests were identical. This suggests that the graduate students provided an adequate model of the professional population and that the much greater expense of conducting studies with professionals may not always be required.     

The construction, testing, and installation of a 6500 r.p.m.15000-hp adjustable-speed electric drive for a centrifugal gascompressor

A power electronic converter is applied to control the speed of a 5 kV motor. The motor is directly coupled to a 6500 r.p.m. compressor and replaces a steam turbine. Dual converters are used in a twelve-pulse arrangement at both the utility and the motor. The motor is of solid rotor construction, with dual 30° displaced stator windings. Finite-element analysis is used to optimize the motor design for use with a variable-frequency static converter. Full-power tests are completed which confirm theoretical predictions on losses, performance, and operation. The electrical drive takes up considerably less space and is much more efficient than the steam turbine it replaces     

MetiTarski: An Automatic Theorem Prover for Real-Valued Special Functions

Many theorems involving special functions such as ln, exp and sin can be proved automatically by MetiTarski: a resolution theorem prover modified to call a decision procedure for the theory of real closed fields. Special functions are approximated by upper and lower bounds, which are typically rational functions derived from Taylor or continued fraction expansions. The decision procedure simplifies clauses by deleting literals that are inconsistent with other algebraic facts. MetiTarski simplifies arithmetic expressions by conversion to a recursive representation, followed by flattening of nested quotients. Applications include verifying hybrid and control systems.     

On the Earth's surface energy exchange determination from ERS satellite ATSR data. Part I: Long-wave radiation

This is the first in a series of papers which addresses the determination of the Earth's surface energy exchange using data from the Along-Track Scanning Radiometer (ATSR). This paper focuses on long-wave radiation from sea and land surfaces and a technique is proposed for the derivation of land surface temperature (LST) and land surface emissivity retrieval using ATSR data in a new simultaneous split-window method. Two points regarding net long-wave radiation are also considered. Firstly, over land and sea, differences in several previously published are discussed. Secondly, over sea, the effect on the net longwave radiation of using sea surface skin temperatures, which can be derived accurately from satellite thermal band data, as input to the empirical formulae is compared to the use of bulk water temperature taken from in situ measurements. Finally, a new formula is developed for the calculation of net long-wave radiation at the surface. The equivalent sky temperature, T, is used and the results agree sky with those obtained using the Oberhuber formula. Both of these formulae are useful for the calculation of net long-wave radiation over wet areas such as sea, with a high relative humidity. Initial tests of the formulae were carried out using ATSR sea surface temperatures (SSTs) and LSTs in the United Kingdom. The formulae were also tested using TOGA-TAO data and ATSR sea surface temperatures over the Pacific Ocean. From our results, the net long-wave radiation showed the magnitude and spatial variability to be (15-35 W m 2). The absolute difference of net long-wave radiation by using ATSR SST and TOGA SST is around 3 W m 2 for most areas, but the maximum difference is up to 7W m 2. The relative difference is more than 10% and up to 30%.