bluuebunny/crossref_metadata_2025 huggingface dataset:
Epicyclic Gearing for Gas Turbine Main Propulsion
Authors: Yates D. E.
Published: April 2015

The success of epicyclic gears in marine main propulsion has been well established. Their small size and weight has led to their introduction in many types of vessel. Epicyclic gears were used in many of the very early naval gas turbine powered vessels and, indeed since then, nearly 250 gears have been supplied for use with a marinized version of the “Proteus” gas turbine. The construction of this and other gas turbine propulsion gears is discussed in some detail to illustrate the basic concepts and design of the gearing. Because of the difficulties in providing astern power in a gas turbine powered ship without the use of a C.P. propeller, there has been interest in the use of a high power reversing gear. Here epicyclic gearing shows a definite advantage over the equivalent alternatives and indeed was used in the naval vessels referred to earlier. Some of the parameters relating to large reversing epicyclic gears are described and the future role of reversing gears is discussed. The description of recently delivered merchant marine triple reduction epicyclic gears is given. The gears transmit 8200 kw from an industrial type of gas turbine and are each installed in a 45,000 tons bulk carrier. Epicyclic gears have played a significant role in the development of gas turbine ship’s propulsion and their future role is discussed in relation to present and projected requirements.
Design and Development of High Horsepower Marine Planetary Gears
Authors: Folenta D. J. , Motzer J. , Critelli F. X.
Published: April 2015

This paper presents the rationale for the design and development of high horsepower marine planetary gears along with the results of some engineering studies and a progress report covering the development testing of full-scale 40,000- and 60,000-shp marine planetary transmission modules. Recent trends in ship construction, modularization, and introduction of new marine prime movers has given the impetus to the design and development of a family of modular form marine planetary reduction gears. Work completed to date including detail gear designs, transmission hardware trade-off studies, marine architectural installation studies, actual hardware manufacturing and testing, as well as information published in the literature on the use of and the performance of marine planetary gears, shows that the concept of high horsepower marine planetary gears is viable and that substantial benefits will accrue to the owner and the user of this type of equipment. Work described herein related to a joint Curtiss-Wright Power Subsystems/Maritime Administration project on planetary Marine Transmission System Development (Contract Nos. 1-35536 and 3-36247).
Experimental Evaluation of an Axial-Flow Transonic Compressor
Authors: Tamaki T. , Nagano S.
Published: April 2015

A five-stage transonic compressor was designed and tested to obtain overall performance and surge limits over a wide rotational speed range. Compressor surge limits are evaluated using individual stage performance characteristics with the aid of a single-stage test. These show that surging at low rotational speed occurs when rotating stall occurs in the first stage and that the wider operating range multi-stage compressor can be realized with the lower aspect ratio blades. On the basis of these test results, a simple model is constructed in order to evaluate the effect of the axial velocity ratio on the flow in a rotor blade row.
Binary Plant Cycle Studies for the Gas Turbine HTGR
Authors: Schuster J. R. , Vrable D. L. , Huntsinger J. P.
Published: April 2015

The Gas Turbine High-Temperature Gas Cooled Reactor (GT-HTGR) employs a power cycle that commences waste heat rejection at relatively high temperature, thus making the use of dry cooling economically attractive. This heat can also be utilized by a low temperature secondary cycle that generates additional power at no increase in fuel cost. A supercritical Rankine cycle employing ammonia as the working fluid meets the requirements for the secondary power cycle. To achieve best overall performance for the combined binary cycle the helium recuperator, and precooler proposed for the dry-cooled GT-HTGR will require modification. Ammonia desuperheats upon expansion through a turbine, and care must be exercised to select cycle conditions that do not result in moisture formation or excessive superheat in the secondary power turbine exhaust. The combined plant output is sensitive to heat sink conditions, and for once-through cooling a 3000-MW(t) binary cycle GT-HTGR produces a net output of 1378 MW(e), which corresponds to an efficiency of 45.9 percent. For evaporative cooling, the output and efficiency are 1353 MW(e) and 45.1 percent, respectively. The heat-rejection system accounts for a large portion of the secondary plant cost, and requires careful optimization while accounting for the effects on plant performance.
Low- and High-Speed Cascade Tests of Air-Cooled Turbine Blades
Authors: Yoshida T. , Minoda M. , Sakata K. , Nouse H. , Takahara K. , Matsuki M.
Published: April 2015

Two-dimensional turbine cascade tests have been carried out in order to make sure of aerodynamic and cooling performances and study the influence of the coolant ejection from the blade surface of the air-cooled turbine cascade in advance of their application to high temperature turbines. Several kinds of air-cooled nozzle and rotor blades have been tested in two cascade wind tunnels of different types. Chordwise distributions of the cooling effectiveness, mean cooling effectivenesses, iso-thermal contours on the blade surface by infrared thermal cameras, and the effects of coolant ejection on the aerodynamic performance are presented.
Logistic Support of Aero Derivative Marine Gas Turbines in the Royal Navy
Authors: Wright G. P.
Published: April 2015

Aero derivative gas turbines, such as those now entering service with the Royal Navy, require a more sophisticated approach to logistic support than conventional marine equipment. A policy of upkeep by exchange was adopted, and computer modeling has been used to predict spares’ requirements. The high rate of equipment modification resulted in the adoption of tight configuration control to ensure efficient spares provisioning.
Prediction of Modal Damping of Jet Engine Stator Vanes Using Finite Element Techniques
Authors: Trompette P. , Paulard M. , Lalanne M. , Jones D. I. G. , Parin M. L.
Published: April 2015

A finite-element analysis utilizing isoparametric elements is used to predict the modal damping and resonant frequencies of a jet engine high pressure compressor stator vane with a damping treatment in the form of an enamel coating applied to the surface. The results of the finite-element analysis are shown to agree well with experimentally measured data. The ultimate advantage of this particular finite-element approach is that it can be applied at very low cost to predicting the effect of many types of damping treatment on modal damping and resonant frequencies of practically any structural component, as well as stress levels if the excitation forces are known.
A Non-Orthogonal Numerical Method for Solving Transonic Cascade Flows
Authors: Dodge P. R.
Published: April 2015

Recently, external transonic aerodynamic methods have shifted from time-dependent methods to relaxation methods, and have been applied to cascade flows. The results were excellent for supercritical compressor cascades, but for more general transonic conditions, the methods proved inadequate. Detailed studies of a choked turbine cascade and corresponding compressor cascades led to the tentative conclusion that the difficulty was associated with a lack of correspondence between the difference star and differential equation region of influence. The analytical approach developed herein avoids this difficulty by construction of difference stars along a non-orthogonal grid system closely aligned to characteristic lines.
Flow Prediction in Axial Flow Compressors Including End-Wall Boundary Layers
Authors: Hirsch Ch.
Published: April 2015

The end-wall boundary-layer theory of Mellor and Wood has been reformulated in streamline coordinates and extended to include predictions for complete velocity profiles in the end-wall regions. Application to a model compressor shows that all parameters vary in the sense expected from known experimental data. These parameters include variable shape factors, skin friction coefficient, and wall skewing angles. The analysis developed has been coupled to a mainstream flow calculations program based on finite elements. Application to axial flow compressors permits the prediction of the complete velocity triangles, including the wall regions and the end-wall losses. Comparisons with experimental results are presented.
Deposits From Heated Gas Turbine Fuels
Authors: Szetela E. J.
Published: April 2015

Deposits from gas turbine fuels are a major concern when prevaporized-premixed combustor concepts are considered for gas turbine engines. Even in conventional gas turbines, deposits are occasionally found in fuel nozzles after a long period of operation. A search was made for information regarding deposits from heated gas turbine fuels using open literature data and data generated within United Technologies Corporation. Summaries of both the data obtained from this survey and the physical and chemical mechanisms leading to the formation of fuel deposits are presented. Data obtained by Pratt and Whitney Aircraft at the Florida Research and Development Center indicate that deposits were suppressed while the fuel was vaporized by mixing with air at velocities of 6 to 13 fps (15 to 33 cm/sec) and pressures of 50 to 200 psia (3.4 to 14 atm). Data obtained at United Technologies Research Center showed that deposits can also be prevented by intermittent use of heated air. Data obtained at EXXON and at the Naval Research Laboratory show that although deposits increase with temperature, a peak is found at about 700 F (682 K). Fuel vaporization was shown to increase the deposit levels in experiments at the Air Force Aero Propulsion Laboratory.
Net Section Rings for Gas Turbines by Isothermal Rolling
Authors: Metcalfe A. G. , Rose F. K. , Thorsrud E. C.
Published: April 2015

Isothermal rolling is performed with refractory metal rolls and uses electrical resistance to heat a local region of the roll and the workpiece for shaping. Reductions of 90 percent per pass can be achieved by this process using forced feed of the workpiece into the rolls. Ring rolling is performed with a small modification of the equipment, and many of the processes used to roll straight sections have been applied to rings. Isothermal ring rolling starts with readily available barstock that is cold rolled to a circular blank and fusion welded. Isothermal rolling works the weld and produces a net shape of high quality. Very significant savings result from reduced metal consumption and elimination of major machining costs. Two methods of gage control and two methods of diametrical control are discussed. Circumferential control within 0.01 percent has been demonstrated, although subsequent stress relief and sizing by cold expanding are recommended in most cases. Examples of ring rolling in steel, titanium, and superalloys are described.
Aerodynamics and Heat Transfer at the Trailing Edge of Transonic Blades
Authors: Amana O. M. , Demuren H. O. , Louis J. F. , Sieverding C. , Chauvin J.
Published: April 2015

A base flow model has been proposed which, apart from predicting the base pressure, also predicts the wake angle and the trailing edge shock system to a good degree of accuracy. The method may also handle a round trailing edge which is important in transonic blades for reducing losses. The base pressure found in the above is then used in the prediction of some of the parameters in the heat-transfer model. The trailing edge heat-transfer model explains and correlates experimental data, for film cooling the trailing edge, obtained using short duration techniques. The results show that film cooling may be used in cooling the trailing edges of transonic blades effectively, provided that the coolant port is located just beyond a critical distance upstream of the trailing edge. The critical distance is the distance required for the coolant flow which separates at injection to reattach downstream and depends on the momentum ratio of coolant to mainstream flows, on the angle of injection, and the flow Reynolds number.
Dielectrophoretic manipulation of individual nickel nanowires for electrical transport measurements
Authors: Puydinger dos Santos Marcos V. , Lima Lucas P. B. , Mayer Rafael A. , Béron Fanny , Pirota Kleber R. , Diniz Jose A.
Published: April 2015

Nanowires (NW) have received much attention due to their high aspect ratio, shape anisotropy, relatively large surface area and particular electron transport properties. In addition, since NW present low current levels and high sensitivity, they can be used as sensor devices for several applications. One of the major challenges when dealing with transport measurements in NW is to trap them between electrodes, which allow electrical characterization and therefore fabrication of nanowire-based devices. Electrically neutral NW can be deposited by dielectrophoresis (DEP) method, which requires the application of an alternating electric field between electrodes. In this work, properly dispersed Ni nanowires (NiNW) (length = 4 ± 1 μm, diameter = 35 ± 5 nm) were deposited on top of Pt electrodes using the DEP method. The effects of electrodes geometry and electric field frequency on DEP efficiency were evaluated. For optimized DEP parameters, the process efficiency is up to 85%. The deposited NiNW exhibit a Schottky-like current versus voltage behavior due to the high contact resistance between NiNW and electrode. Its reduction down to two orders of magnitude, reaching value less than the NiNW resistance (∼6 kΩ), was achieved by depositing a 10 nm-thick Pt layer over the NW extremities. Therefore, this method presents a selection of adequate electrical DEP parameters and electrode geometry, making it a suitable process of NW deposition and electrical characterization. This can be used for investigation of electrical transport properties of individual NW and fabrication of NW-based devices, like sensors and field effect transistors.
A Modification to Maxwell's Needle Apparatus
Authors: Soorya Tribhuvan N.
Published: April 2015

Maxwell's needle apparatus is used to determine the shear modulus (η) of the material of a wire of uniform cylindrical cross section. Conventionally, a single observation is taken for each observable, and the value of η is calculated in a single shot. A modification to the above apparatus is made by varying one of the observables, namely the mass of the hollow cylinder (mh). With this modification five sets of values of mass difference (ms − mh) are taken and corresponding values of difference of the squares of time periods (T22 − T12) are plotted on the graph for calculating the value of η.
Light-Emitting Diodes: Solving Complex Problems
Authors: Planinšič Gorazd , Etkina Eugenia
Published: April 2015

This is the fourth paper in our Light-Emitting Diodes series. The series aims to create a systematic library of LED-based materials and to provide readers with the description of experiments and the pedagogical treatment that would help their students construct, test, and apply physics concepts and mathematical relations. The first paper1 provided an overview of possible uses of LEDs in physics courses. The second paper2 discussed how one could help students learn the foundational aspects of LED physics through a scaf-folded inquiry approach, specifically the ISLE cycle. The third paper3 showed how the physics inherent in the functioning of LEDs could help students deepen their understanding of sources of electric power and the temperature dependence of resistivity, and explore the phenomenon of fluorescence also using the ISLE cycle.4 The goal of this fourth paper is to use LEDs as black boxes that allow students to study certain properties of a system of interest, specifically mechanical, electric, electromagnetic, and light properties. The term “black box” means that we use a device without knowing the mechanism behind its operation.
Are You Ready, Kids? It's SpongeBob Triclops!
Authors: Ribeiro Jair Lúcio Prados
Published: April 2015

If an object is conveniently located in front of two plane mirrors placed at an angle, an observer can see a superposition of images that results in a face with three eyes, called in this text a triclops. The conditions of occurrence of such an image may seem trivial, but this is incorrect: rather, the correct interpretation of this image requires a fine geometric look. In this article, we developed a simple geometric model to determine the conditions under which the triclops can be seen, involving only concepts of plane geometry and trigonometry.
Measuring Astronomical Distances with Linear Programming
Authors: Narain Akshar
Published: April 2015

A few years ago it was suggested that the distance to celestial bodies could be computed by tracking their position over about 24 hours and then solving a regression problem. One only needed to use inexpensive telescopes, cameras, and astrometry tools, and the experiment could be done from one's backyard. However, it is not obvious to an amateur what the regression problem is and how to solve it. This paper identifies that problem and shows how to solve it with linear programming. It also takes into account the body's celestial latitude to improve the method's accuracy. The new method is validated both with simulated and actual data to compute distances to asteroids to within 1% of correct values. It can be used as a new tutorial for amateurs to see how consumer-grade astrophotography and free astrometry and optimization tools come together to solve an important problem. It can also be used as a tool in crowdsourced detection of dangerous asteroids.
Debunking a Video on YouTube as an Authentic Research Experience
Authors: Davidowsky Philip , Rogers Michael
Published: April 2015

Students are exposed to a variety of unrealistic physical experiences seen in movies, video games, and short online videos. A popular classroom activity has students examine footage to identify what aspects of physics are correctly and incorrectly represented.1–7 Some of the physical phenomena pictured might be tricks or illusions made easier to perform with the use of video, while others are removed from their historical context, leaving the audience to form misguided conclusions about what they saw with only the information in the video. One such video in which the late Eric Laithwaite, a successful British engineer and inventor, claims that a spinning wheel “becomes light as a feather” provides an opportunity for students to investigate Laithwaite's claim.8 The use of video footage can engage students in learning physics9 but also provide an opportunity for authentic research experiences.
Popping a balloon with spaghetti
Authors: Planinšič Gorazd , Etkina Eugenia
Published: April 2015

Imagine a balloon sitting on a tabletop. The balloon is free to move. You take one uncooked spaghetti noodle. Can you pop the balloon with this spaghetti? If you try, you will quickly see that you cannot [Fig. 1(a)]. You might think that the reason for the failure is the movement of the balloon. As it is not supported by anything, it moves away the moment you touch it with the spaghetti. But you also observe that the noodle breaks. Are these the explanations of your lack of success? To test both explanations of the balloon popping failure, the movement of the balloon (E1) and breaking of the spaghetti noodle (E2), we will perform testing experiments.
Physics of flying
Authors: Vetrone Jim
Published: April 2015

Column editor's note: As the school year comes to a close, it is important to start thinking about next year. One area that you want to consider is field trips. Many institutions require that teachers plan for a field trip well in advance. Keeping that in mind, I asked Jim Vetrone to write an article about the fantastic field trip he takes his AP Physics students on. I had the awesome opportunity to attend a professional development day that Jim arranged at iFLY in the Chicago suburbs. The experience of “flying” in a wind tunnel was fabulous. Equally fun was watching the other physics teachers come up with experiments to have the professional “flyers” perform in the tube. I could envision my students being similarly excited about the experience and about the development of their own experiments. After I returned to school, I immediately began the process of trying to get this field trip approved for the 2015–16 school year. I suggest that you start your process as well if you hope to try a new field trip next year. The key to getting the approval, in my experience, is submitting a proposal early that includes supporting documentation from sources. Often I use NGSS or state standards as justifications for my field trips. I have also quoted College Board expectations for AP Physics 1 and 2 in my documents when requesting an unusual field trip.
Adiponectin, Resistin, and Visfatin in Childhood Obesity and Exercise
Authors: Jamurtas Athanasios Z. , Stavropoulos-Kalinoglou Antonios , Koutsias Stilianos , Koutedakis Yiannis , Fatouros Ioannis
Published: April 2015

Childhood obesity is increasing alarmingly, and a strong association with chronic diseases has been established. Specific adipokines are released from the adipose tissue and relate with chronic diseases even in the pediatric population. Adiponectin levels are lower in obesity and increase with decreasing body weight. A few pediatric studies examining a possible relationship between resistin and obesity do not provide a clear picture. Most studies agree that visfatin levels appear elevated in childhood obesity. Exercise seems to increase adiponectin levels whereas resistin levels are reduced. The lack of data on the effects of acute and chronic exercise on visfatin levels precludes us from making safe conclusions as to what the effects of exercise (acute or chronic) would be on visfatin levels in children. Clearly, exercise has an impact on the adipose tissue and the release of adiponectin, resistin, and visfatin. However, other factors affect the secretion rate of these adipokines from the adipose tissue; these factors should also be taken into consideration when examining the effects of exercise on adipokines. Gender, age, body composition, physical activity levels, mode and intensity of exercise are some of the factors that should be looked into in future studies.
Effect of Age, Sex, and Race Distance on Front Crawl Stroke Parameters in Subelite Adolescent Swimmers During Competition
Authors: Dormehl Shilo , Osborough Conor
Published: April 2015

The aims of this study were to determine the effect of age, sex and race distance on velocity (v), stroke rate (SR), stroke length (SL) and stroke index (SI) of subelite adolescent swimmers in competition, and to investigate their pacing strategies during the 100-m and 200-m events. Video footage of 112 adolescent swimmers (56 female; 56 male), competing in the 100-m and 200-m freestyle events, in two age groups (12–14; 15–18 years) was recorded and subsequently analyzed. A MANOVA showed that all stroke parameters significantly differed between sexes and between race distances. The older adolescents had a higher v, a longer SL and a greater SI (p < .01) than the younger adolescents. There were significant interaction effects between age and sex for v, SL and SI. Most adolescents had a SL that was within 7% of that reported for 1992 Olympians, but had up to 16% lower SRs. Separate Friedman’s ANOVAs showed that SL differed between successive race quarters for both age groups, both sexes and both race distances. It is likely that physical immaturity, inexperience in competition pacing and within-race fatigue strongly influence the performances of subelite adolescent front crawl swimmers.
Effects of Aerobic Plus Resistance Exercise on Body Composition Related Variables in Pediatric Obesity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Authors: García-Hermoso Antonio , Sánchez-López Mairena , Martínez-Vizcaíno Vicente
Published: April 2015

The purpose of this meta-analysis of randomized trials was to determine the effectiveness of aerobic plus resistance exercise interventions on body composition related to variables in overweight and obese youth. A computerized search was made of 7 databases. The analysis was restricted to randomized controlled trials that examined the effect of aerobic and resistance exercise on body composition (body weight, body mass index, fat mass, fat-free mass, and waist circumference) in obese youth. Two independent reviewers screened studies and extracted data. Weighted mean differences (WMD) and 95% confidence intervals were calculated. Nine studies were selected for meta-analysis as they fulfilled the inclusion criteria (n = 365). Aerobic plus resistance exercise interventions (8–24 weeks duration) produced a decrease in body weight (WMD=-3.31 kg), body mass index (WMD=-1.05 kg/m2), and fat mass (WMD=-1.93% and 5.05 kg), but changes in fatfree mass and waist circumference were not observed. These changes were accentuated through programs of at least 60 min of exercise per session, generating greater reductions in body weight (WMD=-4.11 kg), fat mass (WMD=-4.07%), and increase in fat-free mass (WMD = 2.45 kg). This meta-analysis provides insight into the effectiveness of short-term aerobic plus resistance exercise interventions for decreasing body weight, body mass index, and fat mass in pediatric obesity.
Moderate-to-Vigorous Physical Activity and Sedentary Behavior: Independent Associations With Body Composition Variables in Brazilian Children
Authors: de Moraes Ferrari Gerson Luis , Oliveira Luis Carlos , Araujo Timoteo Leandro , Matsudo Victor , Barreira Tiago V. , Tudor-Locke Catrine , Katzmarzyk Peter
Published: April 2015

This study aimed to analyze the independent associations of accelerometer-determined sedentary behavior, physical activity, and steps/day with body composition variables in Brazilian children. 485 children wore accelerometers for 7 days. Variables included time in sedentary behavior and different physical activity intensities (light, moderate, vigorous, or moderate-to-vigorous) and steps/day. Body fat percentage was measured using a bioelectrical impedance scale, and BMI was calculated. Children spent 55.7% of the awake portion of the day in sedentary behavior, 37.6% in light physical activity, 4.6% in moderate physical activity, and 1.9% in vigorous physical activity. Moderate-to-vigorous physical activity and steps/day were negatively associated with body composition (BMI and body fat percentage) variables, independent of sex and sedentary behavior. Beta values were higher for vigorous physical activity than moderate physical activity. Vigorous physical activity was negatively associated with BMI (β-.1425) and body fat percentage (β-.3082; p < .0001). In boys, there were significant negative associations between moderate, vigorous, and moderate-to-vigorous physical activity and steps/day with body composition, and in girls, there was only a negative association with vigorous physical activity, independent of sedentary behavior. Moderate-to-vigorous physical activity and steps/day (in boys), but especially vigorous physical activity (in boys and girls), are associated with body composition, independent of sedentary behavior. Sedentary behavior was not related with any of the body composition variables once adjusted for moderate-to-vigorous physical activity.
A sticky situation helps colitis
Authors: Traverso Giovanni
Published: April 2015

A liquid drug that changes to a gel when exposed to body heat shows promise as a topical treatment for inflammatory bowel disease.
Hybrid Vibrio cholerae El Tor Lacking SXT Identified as the Cause of a Cholera Outbreak in the Philippines
Authors: Klinzing David C. , Choi Seon Young , Hasan Nur A. , Matias Ronald R. , Tayag Enrique , Geronimo Josefina , Skowronski Evan , Rashed Shah M. , Kawashima Kent , Rosenzweig C. Nicole , Gibbons Henry S. , Torres Brian C. , Liles Veni , Alfon Alicia C. , Juan Maria Luisa , Natividad Filipinas F. , Cebula Thomas A. , Colwell Rita R.
Published: April 2015

Cholera continues to be a global threat, with high rates of morbidity and mortality. In 2011, a cholera outbreak occurred in Palawan, Philippines, affecting more than 500 people, and 20 individuals died.
Vibrio cholerae
O1 was confirmed as the etiological agent. Source attribution is critical in cholera outbreaks for proper management of the disease, as well as to control spread. In this study, three
V. cholerae
O1 isolates from a Philippines cholera outbreak were sequenced and their genomes analyzed to determine phylogenetic relatedness to
V. cholerae
O1 isolates from recent outbreaks of cholera elsewhere. The Philippines
V. cholerae
O1 isolates were determined to be
V. cholerae
O1 hybrid El Tor belonging to the seventh-pandemic clade. They clustered tightly, forming a monophyletic clade closely related to
V. cholerae
O1 hybrid El Tor from Asia and Africa. The isolates possess a unique multilocus variable-number tandem repeat analysis (MLVA) genotype (12-7-9-18-25 and 12-7-10-14-21) and lack SXT. In addition, they possess a novel 15-kb genomic island (GI-119) containing a predicted type I restriction-modification system. The CTXΦ-RS1 array of the Philippines isolates was similar to that of
V. cholerae
O1 MG116926, a hybrid El Tor strain isolated in Bangladesh in 1991. Overall, the data indicate that the Philippines
V. cholerae
O1 isolates are unique, differing from recent
V. cholerae
O1 isolates from Asia, Africa, and Haiti. Furthermore, the results of this study support the hypothesis that the Philippines isolates of
V. cholerae
O1 are indigenous and exist locally in the aquatic ecosystem of the Philippines.

IMPORTANCE
Genetic characterization and phylogenomics analysis of outbreak strains have proven to be critical for probing clonal relatedness to strains isolated in different geographical regions and over time. Recently, extensive genetic analyses of
V. cholerae
O1 strains isolated in different countries have been done. However, genome sequences of
V. cholerae
O1 isolates from the Philippines have not been available for epidemiological investigation. In this study, molecular typing and phylogenetic analysis of
Vibrio cholerae
isolated from both clinical and environmental samples in 2011 confirmed unique genetic features of the Philippines isolates, which are helpful to understand the global epidemiology of cholera.
Spontaneous bacterial peritonitis: an unusual manifestation of brucellosis in a previous healthy male patient
Authors: Makaritsis Konstantinos P , Liaskos Christos , Papadamou Georgia , Dalekos George N
Published: April 2015

Brucellosis is a common zoonotic disease with worldwide distribution and protean clinical manifestations. Therefore, its prompt and timely diagnosis is still challenging. Among several complications of brucellosis, spontaneous bacterial peritonitis (SBP) in previously healthy participants is rarely recognised, although this condition can be fatal if misdiagnosed and untreated. We present a case of a 69-year-old previously healthy stockbreeder who suffered from back pain along with abdominal pain and distension because of ascites of 6–8 weeks duration. Cultures of ascitic fluid and peripheral blood specimens revealedBrucellaspp as the causative agent of ascites and spondylodiscitis, which was then confirmed by MRI findings. After appropriate treatment for 4.5 months (streptomycin 1 g/day for 3 weeks intramuscularly, doxycycline 100 mg twice a day orally and rifampicin 900 mg/day orally), the patient fully recovered. Conclusively, in the appropriate epidemiological and clinical setting, the consideration of brucellosis in the differential diagnosis of SBP could be rational as well as life-saving.
Successful management of chronic high-output ileostomy with high dose loperamide
Authors: Mackowski Alicia , Chen Han-Kuang , Levitt Michael
Published: April 2015

High-stoma output is a common problem that can lead to dehydration and electrolyte disturbance. The following report describes three patients with end ileostomy who had high-stoma outputs where conventional medical management was unsuccessful in controlling stoma output. All three patients responded to high-dose loperamide, resulting in significant clinical improvement. High-dose loperamide therapy should be considered in patients with high-stoma output who have failed conventional medical management.
Risk factors which predispose first-time traumatic anterior shoulder dislocations to recurrent instability in adults: a systematic review and meta-analysis
Authors: Olds M , Ellis R , Donaldson K , Parmar P , Kersten P
Published: April 2015

Background

Recurrent instability following a first-time anterior traumatic shoulder dislocation may exceed 26%. We systematically reviewed risk factors which predispose this population to events of recurrence.

Methods

A systematic review of studies published before 1 July 2014. Risk factors which predispose recurrence following a first-time traumatic anterior shoulder dislocation were documented and rates of recurrence were compared. Pooled ORs were analysed using random-effects meta-analysis.

Results

Ten studies comprising 1324 participants met the criteria for inclusion. Recurrent instability following a first-time traumatic anterior shoulder dislocation was 39%. Increased risk of recurrent instability was reported in people aged 40 years and under (OR=13.46), in men (OR=3.18) and in people with hyperlaxity (OR=2.68). Decreased risk of recurrent instability was reported in people with a greater tuberosity fracture (OR=0.13). The rate of recurrent instability decreased as time from the initial dislocation increased. Other factors such as a bony Bankart lesion, nerve palsy and occupation influenced rates of recurrent instability.

Conclusions

Sex, age at initial dislocation, time from initial dislocation, hyperlaxity and greater tuberosity fractures were key risk factors in at least two good quality cohort studies resulting in strong evidence as concluded in the GRADE criteria. Although bony Bankart lesions, Hill Sachs lesions, occupation, physiotherapy treatment and nerve palsy were risk factors for recurrent instability, the evidence was weak using the GRADE criteria—these findings relied on poorer quality studies or were inconsistent among studies.
Serial measurement of Wessex Head Injury Matrix in the diagnosis of patients in vegetative and minimally conscious states: a cohort analysis
Authors: Turner-Stokes Lynne , Bassett Paul , Rose Hilary , Ashford Stephen , Thu Aung
Published: April 2015

Objective

To evaluate serial application of the Wessex Head Injury Matrix (WHIM) in diagnosis of prolonged disorders of consciousness (PDOC). Specifically, to determine whether the trajectory of change predicts outcome status, and whether the current hierarchical order of WHIM items is correct for this context.

Design

Analysis of prospectively gathered clinical cohort data.

Setting

Consecutive admissions to a tertiary in-patient neurorehabilitation service for evaluation of PDOC in real-life clinical practice, over a 10-year period (2004–2014).

Participants

Patients (n=65) presenting in sudden-onset vegetative (VS) or minimally conscious states (MCS). Mean age 38.4 (sd14.1) years; male:female ratio 66%:33%. Aetiology of brain injury: 40(62%) traumatic; 12(19%) vascular; 11(17%) hypoxic; 3(3%) other.

Primary outcome measure

WHIM alongside detailed clinical evaluation.

Methods

The WHIM was administered serially by the multidisciplinary team throughout an in-patient evaluation programme (mean length 74 (sd42) days). Patients were divided into four groups, according to PDOC status on discharge (VS, MCS-Minus, MCS-Plus or Emerged).

Results

WHIM hierarchical scores (Most Advanced Behaviour (MAB)) correlated with PDOC status at discharge (Pearson r=0.49, p<0.001). In the original order, the MAB distinguished the ‘VS’, ‘MCS’ and ‘Emerged’ categories (analysis of variance (ANOVA) post hoc p<0.001), but not the subgroups of MCS-Minus and MCS-Plus. In stepwise regression analysis, MAB-Ex (excluding two items) accounted for 68% of the variance in PDOC status at discharge. On multilevel statistical modelling, trajectory of change in MAB separated the four PDOC groups, both at individual and at group level (p<0.001). After reordering of items, the new-order MAB accounted for more (73%) of the variance in PDOC status, and also distinguished significantly between MCS-Minus and MCS-Plus groups at discharge (p<0.002).

Conclusions

The WHIM is a useful diagnostic tool in PDOC, and trajectory of change is an important predictor of outcome. The proposed new hierarchical order requires further evaluation in future multicentre analyses.
Health professionals’ and service users’ perspectives of shared care for monitoring wet age-related macular degeneration: a qualitative study alongside the ECHoES trial
Authors: Townsend D , Reeves B C , Taylor J , Chakravarthy U , O'Reilly D , Hogg R E , Mills N
Published: April 2015

Objectives

To explore the views of eye health professionals and service users on shared community and hospital care for wet or neovascular age-related macular degeneration (nAMD).

Method

Using maximum variation sampling, 5 focus groups and 10 interviews were conducted with 23 service users and 24 eye health professionals from across the UK (consisting of 8 optometrists, 6 ophthalmologists, 6 commissioners, 2 public health representatives and 2 clinical eye care advisors to local Clinical Commissioning Groups). Data were transcribed verbatim and analysed thematically using constant comparative techniques derived from grounded theory methodology.

Results

The needs and preferences of those with nAMD appear to be at odds with the current service being provided. There was enthusiasm among health professionals and service users about the possibility of shared care for nAMD as it was felt to have the potential to relieve hospital eye service burden and represent a more patient-centred option, but there were a number of perceived barriers to implementation. Some service users and ophthalmologists voiced concerns about optometrist competency and the potential for delays with referrals to secondary care if stable nAMD became active again. The health professionals were divided as to whether shared care was financially more efficient than the current model of care. Specialist training for optometrists, under the supervision of ophthalmologists, was deemed to be the most effective method of training and was perceived to have the potential to improve the communication and trust that shared care would require.

Conclusions

While shared care is perceived to represent a promising model of nAMD care, voiced concerns suggest that there would need to be greater collaboration between ophthalmology and optometry, in terms of interprofessional trust and communication.

Trial registration number

ISRCTN07479761.
Does a quality management system improve quality in primary care practices in Switzerland? A longitudinal study
Authors: Goetz Katja , Hess Sigrid , Jossen Marianne , Huber Felix , Rosemann Thomas , Brodowski Marc , Künzi Beat , Szecsenyi Joachim
Published: April 2015

Objectives

To examine the effectiveness of the quality management programme—European Practice Assessment—in primary care in Switzerland.

Design

Longitudinal study with three points of measurement.

Setting

Primary care practices in Switzerland.

Participants

In total, 45 of 91 primary care practices completed European Practice Assessment three times.

Outcomes

The interval between each assessment was around 36 months. A variance analyses for repeated measurements were performed for all 129 quality indicators from the domains: ‘infrastructure’, ‘information’, ‘finance’, and ‘quality and safety’ to examine changes over time.

Results

Significant improvements were found in three of four domains: ‘quality and safety’ (F=22.81, p<0.01), ‘information’ (F=27.901, p<0.01) and ‘finance’ (F=4.073, p<0.02). The 129 quality indicators showed a significant improvement within the three points of measurement (F=33.864, p<0.01).

Conclusions

The European Practice Assessment for primary care practices thus provides a functioning quality management programme, focusing on the sustainable improvement of structural and organisational aspects to promote high quality of primary care. The implementation of a quality management system which also includes a continuous improvement process would give added value to provide good care.
Seroprevalence and awareness of human papillomavirus infection and cervical cancer screening results among reproductive-aged Georgian women
Authors: Butsashvili Maia , Abzianidze Tinatin , Kajaia Maia , Agladze Dodo , Kldiashvili Ekaterine , Bednarczyk Robert , McNutt Louise-Anne , Kamkamidze George
Published: April 2015

Introduction

As is the case in many developing countries, more than half of the new cervical cancer cases in Georgia are late-stage diagnoses, thus reducing the opportunity for effective treatment. A state cancer screening programme was launched in Tbilisi in 2006; 5 years later the programme had expanded to other regions in Georgia.

Methods

This study was designed to estimate awareness about human papillomavirus (HPV), cervical cancer screening, the HPV vaccine, and the seroprevalence of HPV infection among reproductive-aged Georgian women. Study participants were recruited from four women's consultation centres in different regions of Georgia. Data were collected through interviewer-administered questionnaires and HPV seroprevalence was assessed for HPV types 6/11/16/18.

Results

Of the 500 study participants, 52.0% were aware of HPV and 36.4% stated that the main cause of cervical cancer is HPV. Of those aware of HPV, 78% reported attending for cervical cancer screening at least once during their lifetime. Half (50.8%) of all respondents were unaware of the HPV vaccine. Of the women who agreed to be tested for anti-HPV antibodies (n=317), 21.1% were positive. Women reporting no condom use were more likely to have HPV antibodies (prevalence ratio 2.77; 95% confidence interval 1.79–4.27). Awareness of cervical cancer screening was significantly associated with HPV seropositivity. With multivariate analysis, both absence of condom use and lack of knowledge about cervical cancer screening were independently associated with HPV seropositivity.

Conclusion

More comprehensive public awareness campaigns should be developed to raise awareness about HPV screening and prevention.
Factors associated with discussion of sexual activity and contraception in women with HIV
Authors: Stewart Zoe A , Shipley Kate , Spelman Tim , Giles Michelle L
Published: April 2015

Objectives

Contraceptive use is important for reproductive-aged women living with HIV to plan and optimise safety of pregnancies. Clinicians play a vital role in counselling patients about contraception and safe sexual activity. This study aimed to determine the frequency and predictors of discussions regarding sexual activity and contraceptive use.

Methods

Retrospective clinical study of all reproductive-aged women (n=128) treated for HIV between 2010 and 2012 at two metropolitan hospitals. Evidence of discussion between treating doctors and patients regarding sexual activity and contraception and variables including patient age, gender of doctor, time since HIV diagnosis, previous pregnancy, country of birth and antiretroviral regimen were obtained from medical records.

Results

Sexual activity status was documented for 54% of the women and discussion regarding contraception was recorded for less than one-third of the study participants. Contraceptive use was not recorded in 63% of the medical records. In the study cohort 27% of the women used contraception, 10% did not use contraception, and when a discussion regarding sexual activity was documented, contraception was 3.7 times more likely to also be discussed (p=0.04). Excluding women who were pregnant, women who were documented as using contraception were 1.8 times as likely to have had a discussion about contraception documented (p=0.05). After adjustment for other factors, previous pregnancy, gender of doctor and age of patient were not associated with discussions regarding sexual activity or contraception.

Conclusions

Discussions regarding sexual activity and contraception between HIV-infected women of reproductive age and their clinicians were inconsistent and suboptimal. Mechanisms to facilitate regular discussion about sexual activity and contraception between clinicians and women with HIV warrant further investigation.
Simulation Optimization: A Review and Exploration in the New Era of Cloud Computing and Big Data
Authors: Xu Jie , Huang Edward , Chen Chun-Hung , Lee Loo Hay
Published: April 2015

Recent advances in simulation optimization research and explosive growth in computing power have made it possible to optimize complex stochastic systems that are otherwise intractable. In the first part of this paper, we classify simulation optimization techniques into four categories based on how the search is conducted. We provide tutorial expositions on representative methods from each category, with a focus in recent developments, and compare the strengths and limitations of each category. In the second part of this paper, we review applications of simulation optimization in various contexts, with detailed discussions on health care, logistics, and manufacturing systems. Finally, we explore the potential of simulation optimization in the new era. Specifically, we discuss how simulation optimization can benefit from cloud computing and high-performance computing, its integration with big data analytics, and the value of simulation optimization to help address challenges in engineering design of complex systems.
Transmission coefficient and two-fold degenerate discrete spectrum of spin-1 bosons in a double-step potential
Authors: de Oliveira Luiz P. , de Castro Antonio S.
Published: April 2015

The scattering of spin-1 bosons in a nonminimal vector double-step potential is described in terms of eigenstates of the helicity operator and it is shown that the transmission coefficient is insensitive to the choice of the polarization of the incident beam. Poles of the transmission amplitude reveal the existence of a two-fold degenerate spectrum. The results are interpreted in terms of solutions of two coupled effective Schrödinger equations for a finite square well with additional δ-functions situated at the borders.
Global–Local-Distortional Vibration of Thin-Walled Rectangular Multi-Cell Beams
Authors: Gonçalves Rodrigo , Peres Nuno , Bebiano Rui , Camotim Dinar
Published: April 2015

This paper presents the results of an investigation concerning the free vibration behavior (undamped natural frequencies and vibration mode shapes) of thin-walled beams with rectangular multi-cell cross-section (assemblies of parallel rectangular cells in a single direction). Besides local (plate-type) and global (flexural, torsional and extensional) vibration modes, attention is paid to the relatively less-known distortional vibration modes, which involve cross-section out-of-plane (warping) and in-plane deformation, including displacements of the wall intersections. A computationally efficient semi-analytical Generalized Beam Theory (GBT) approach is employed to obtain insight into the mechanics of the problem. In particular, the intrinsic modal decomposition features of GBT — the fact that the beam is described using a hierarchical set of relevant cross-section deformation modes — are exploited to identify and categorize the most relevant vibration modes and deformation mode couplings.