bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Modeling and Simulation of Viscous Shear in Hydrostatic Bearing
Authors: Kishor Shyam
Published: November 2016

Flow structure inside a thin film lubricating bearing is analyzed using computational approach. Computation Fluid Dynamics is used for detailed analysis of fluid flow and heat transfer through bearing land for different flow rates to investigate load carrying characteristics.

Results from different turbulence models are compared to ensure accurate modeling of transitional flow through the pad. Custom program is added to commercial CFD code to capture temperature dependent viscosity and its impact on load carrying capacity. Temperature, pressure, viscosity and their variations across the pad are captured for loads at different surface speeds. Effect of change in gap size on load carrying capacity of the bearing is examined. Computational results are compared with the experimental measurements.

CFD results are in close agreement with the experimental measurements. Temperature rise due to viscous sheer reduces the load carrying capacity by up to 25 %. Viscous and thermal resistance increases with increase in the flow rate. Additional reduction in load carrying capacity of up to 10 % is observed due to viscous resistance when load is moving. Most of the temperature rise happens in the region of narrow gap outside the recess depth. Pressure, temperature and viscosity variations across the bearing surface are presented.

Effect of motion creates localized thermal gradient due to reverse flow. Nature of temperature variations and locations of localized heating offer greater insight in designing a more efficient hydrostatic bearing for machines at higher speed.
Experimental Study on Thermal Storage Performance of Cylindrically Encapsulated PCM in a Cylindrical Storage Tank With Axial Flow
Authors: Wickramaratne Chatura , Moloney Francesca , Pirasaci Tolga , Kamal Rajeev , Goswami D. Y. , Stefanakos Elias , Dhau Jaspreet
Published: November 2016

A lab-scale packed-bed system was used to test an industry scalable latent heat thermal energy storage (TES) system suitable for supplementing heat to a steam powered cycle. Metallic cylindrical capsules were filled with a eutectic of sodium sulfate (Na2SO4) and potassium chloride (KCl) as the phase change material (PCM) for energy storage. The packed bed system consisted of a cylindrical storage tank with the cylindrical capsules arranged vertically. This system was modeled and validated. The charging and discharging efficiencies of different operating parameters were analyzed. The calculated ratio of exergy to energy efficiency was around 90%. The overall efficiency of the bed, however, was found to be low due to the losses through the packed bed. Possible losses and limitations of the system were analyzed, and recommendations were made for improved designs.
Planning the Field Construction Phase of Feedwater Heater Replacement Projects: Lessons From the Gibson 3G1/3G2 Feedwater Heaters Replacement
Authors: Rister Andrew
Published: November 2016

This paper will discuss some of the necessary details to consider when planning for the field construction portion of a replacement feedwater heater project. Key planning issues for the installation of the new heaters will be discussed, including development of lifting and rigging plans, checking that dimensional changes in the new heaters can be accommodated by the installation area, proper review of field welding procedures, and weld preheat & stress relief requirements. Practical examples from the Gibson Station 3G1/3G2 heater replacements will help emphasize the importance of construction planning as a vital part of feedwater heater replacement project success, contributing just as much to the long, reliable life of the heater as proper design and fabrication.
Performance Analyze of Ultra-Low Emission of Thermal Power Generation Based on Multi-Objective Optimization
Authors: Li Xiaoen , Wang Ningling , Zhang Yumeng , Yang Yongping
Published: November 2016

The present study deals with a multi-objective optimization problem on design condition. A multi-objective algorithm model is established to weigh up the relationship between coal consumption rate and environmental impact of pollutant. A simulated thermodynamic system model of traditional supercritical coal-fired units coupled with environment protect equipment is designed on the platform of Ebsilon. The environmental impact, which consist of the pollutant emission of NOx, SOx and dust, is acquired with the help of support vector machine (SVM) from the historical record of that power plant. The restriction of pollutant emission in Chinese newly policy is taken into account to determine the weighting factor. By considering energy and environment as the multi-objective, the simulation, which evaluates the solutions by interfacing with the programmed optimization algorithm, is developed. And corresponding total system performance and characteristic of pollutant emission in flue gas is derived. The result show that the performance of system and environment protect equipment will be influenced as boundary conditions changed. Coal consumption around 290g/kWh and 292g/kWh can reach minimum environmental impact in the case of our testing power plant.
A Levelized Cost of Energy (LCOE) Model for Wind Farms That Includes Power Purchase Agreement (PPA) Energy Delivery Limits
Authors: Bruck Maira , Goudarzi Navid , Sandborn Peter
Published: November 2016

The cost of energy is an increasingly important issue in the world as renewable energy resources are growing in demand. Performance-based energy contracts are designed to keep the price of energy as low as possible while controlling the risk for both parties (i.e., the Buyer and the Seller). Price and risk are often balanced using complex Power Purchase Agreements (PPAs). Since wind is not a constant supply source, to keep risk low, wind PPAs contain clauses that require the purchase and sale of energy to fall within reasonable limits. However, the existence of those limits also creates pressure on prices causing increases in the Levelized Cost of Energy (LCOE). Depending on the variation in capacity factor (CF), the power generator (the Seller) may find that the limitations on power purchasing given by the utility (the Buyer) are not favorable and will result in higher costs of energy than predicted. Existing cost models do not take into account energy purchase limitations or variations in energy production when calculating an LCOE. A new cost model is developed to evaluate the price of electricity from wind energy under a PPA contract. This study develops a method that an energy Seller can use to negotiate delivery penalties within their PPA. This model has been tested on a controlled wind farm and with real wind farm data. The results show that LCOE depends on the limitations on energy purchase within a PPA contract as well as the expected performance characteristics associated with wind farms.
Performance Analysis of Photovoltaic Thermal (PVT) Panels Considering Thermal Parameters
Authors: Jayasuriya W. J. A. , Athukorala A. U. C. D. , Perera A. T. D. , Sirimanna M. P. G. , Attalage R. A.
Published: November 2016

Solar PVT panels are getting popular for wider spectrum of applications for concurrent heat and power generation (CHP). These panels can provide the heating demand of buildings while generating electricity which becomes ideal for building applications of urban energy systems. Energy flow analysis of such panels and performance analysis of such systems becomes essential to design PVT systems matching with the operating conditions. A number of studies have used both theoretical and experimental methods to optimize PVT. However, this task is challenging due to interrelation of CHP production based on two different phenomena where classical optimization methods cannot be applied directly. Hence basic performance analysis considering primary design parameters plays a major role.

In this study, a computational model is developed to evaluate sensitivity of design, operating and climatic parameters for a hybrid PVT system and to analyze the performances of PVT for five different design configurations. Five main configurations of the PVT system are considered based on the heat transfer fluid and the arrangements of glass and tedlar layers of PVT collector. This study presents comprehensive performance analysis conducted to evaluate the sensitivity of mass flow rate and working fluid temperature for the five different design configurations of PVT panels. Results show that glass-tedlar water collector performs better when compared to other configurations. Subsequently, the sensitivity of wind speed and solar irradiation is evaluated. The behavior of thermal and electrical efficiencies is analyzed at different wind speed and solar irradiation levels for a range of mass flow rates and working fluid temperatures. Important conclusions on the performance of PVT panels are given based on this detailed analysis.
Cross Compound Turbine Generator Unit With Elevated and Conventional Turbine Layouts
Authors: Feng Weizhong
Published: November 2016

This engineering study demonstrates the feasibility and advantages of a cross compound unit with an elevated and conventional turbine layout.

Existing materials and equipment manufacturing capabilities were used to design a double reheat unit using the elevated and conventional turbine layout with other mature energy-saving systems to achieve a net efficiency of 48.92%.

The development of conventional coal-fired power plants is reviewed to describe the existing bottlenecks in high-efficiency Super Critical (SC) and Ultra Super Critical (USC) electrical generation units.

The development of 700 °C Advanced Ultra Super Critical (A-USC) units has been much slower than expected mainly due to the material limitations. Double reheat systems increase efficiency but also significantly increase cost and complexity.

This design reduces the use of expensive high-temperature materials, with significantly lower piping costs as well as lower pressure drops and heat losses which increase the efficiency and the performance-price ratio.
Design and Application of Low Flow Steam Siphon Jet Pumps
Authors: Leishear Robert A. , Bennett William M. , Cooper Jackie
Published: November 2016

Low flow steam siphon jet pumps are referred to as rate jets, since these pumps have the ability to control flow rates by varying the steam pressure applied to the jet. The jet pump design consists of several components. Steam inlet piping is connected to a steam nozzle that directs steam into the jet body to provide energy to lift a liquid, or feed. Feed is lifted up through the suction lift piping, where the condensing steam forces the liquid into a diffuser and out of the jet discharge piping. Closed form equations cannot model these jets, and commercial computer models to describe jet performance are still in a state of development. In general, experimental data is required to determine the performance characteristics of this type of jet design. Numerous tests were performed on different jet designs to evaluate the effects of motive steam pressures, suction lift, discharge head, jet dimensions, and the specific gravity of the fluid that is lifted and pumped by the jet. Additionally, the system installation significantly affects the performance of siphon jets, and one such installation was studied.
Technical Note: Rod phantom analysis for comparison of PET detector sampling and reconstruction methods
Authors: Wollenweber Scott D. , Kemp Brad J.
Published: November 2016

Purpose

This investigation aimed to develop a scanner quantification performance methodology and compare multiple metrics between two scanners under different imaging conditions. Most PET scanners are designed to work over a wide dynamic range of patient imaging conditions. Clinical constraints, however, often impact the realization of the entitlement performance for a particular scanner design. Using less injected dose and imaging for a shorter time are often key considerations, all while maintaining “acceptable” image quality and quantitative capability.

Methods

A dual phantom measurement including resolution inserts was used to measure the effects of in‐plane (x, y) and axial (z) system resolution between two PET/CT systems with different block detector crystal dimensions. One of the scanners had significantly thinner slices. Several quantitative measures, including feature contrast recovery, max/min value, and feature profile accuracy were derived from the resulting data and compared between the two scanners and multiple phantoms and alignments.

Results

At the clinically relevant count levels used, the scanner with thinner slices had improved performance of approximately 2%, averaged over phantom alignments, measures, and reconstruction methods, for the head‐sized phantom, mainly demonstrated with the rods aligned perpendicular to the scanner axis. That same scanner had a slightly decreased performance of −1% for the larger body‐size phantom, mostly due to an apparent noise increase in the images. Most of the differences in the metrics between the two scanners were less than 10%.

Conclusions

Using the proposed scanner performance methodology, it was shown that smaller detector elements and a larger number of image voxels require higher count density in order to demonstrate improved image quality and quantitation. In a body imaging scenario under typical clinical conditions, the potential advantages of the design must overcome increases in noise due to lower count density.
Complementing caspase 11
Authors: Foley John F.
Published: November 2016

Complement signaling increases caspase 11–dependent cell death and worsens sepsis.
New connections: Getting the good without the bad
Authors: Wong Wei
Published: November 2016

Designer hormones possess only the benefits and not the side effects of the endogenous versions.
Dosing and Pharmacokinetics of Polymyxin B in Patients with Renal Insufficiency
Authors: Thamlikitkul Visanu , Dubrovskaya Yanina , Manchandani Pooja , Ngamprasertchai Thundon , Boonyasiri Adhiratha , Babic Jessica T. , Tam Vincent H.
Published: November 2016

Polymyxin B remains the last-line treatment option for multidrug-resistant Gram-negative bacterial infections. Current U.S. Food and Drug Administration-approved prescribing information recommends that polymyxin B dosing should be adjusted according to the patient's renal function, despite studies that have shown poor correlation between creatinine and polymyxin B clearance. The objective of the present study was to determine whether steady-state polymyxin B exposures in patients with normal renal function were different from those in patients with renal insufficiency. Nineteen adult patients who received intravenous polymyxin B (1.5 to 2.5 mg/kg [actual body weight] daily) were included. To measure polymyxin B concentrations, serial blood samples were obtained from each patient after receiving polymyxin B for at least 48 h. The primary outcome was polymyxin B exposure at steady state, as reflected by the area under the concentration-time curve (AUC) over 24 h. Five patients had normal renal function (estimated creatinine clearance [CL
CR
] ≥ 80 ml/min) at baseline, whereas 14 had renal insufficiency (CL
CR
< 80 ml/min). The mean AUC of polymyxin B ± the standard deviation in the normal renal function cohort was 63.5 ± 16.6 mg·h/liter compared to 56.0 ± 17.5 mg·h/liter in the renal insufficiency cohort (
P
= 0.42). Adjusting the AUC for the daily dose (in mg/kg of actual body weight) did not result in a significant difference (28.6 ± 7.0 mg·h/liter versus 29.7 ± 11.2 mg·h/liter,
P
= 0.80). Polymyxin B exposures in patients with normal and impaired renal function after receiving standard dosing of polymyxin B were comparable. Polymyxin B dosing adjustment in patients with renal insufficiency should be reexamined.
Multicenter Study of Method-Dependent Epidemiological Cutoff Values for Detection of Resistance in Candida spp. and Aspergillus spp. to Amphotericin B and Echinocandins for the Etest Agar Diffusion Method
Authors: Espinel-Ingroff A. , Arendrup M. , Cantón E. , Cordoba S. , Dannaoui E. , García-Rodríguez J. , Gonzalez G. M. , Govender N. P. , Martin-Mazuelos E. , Lackner M. , Lass-Flörl C. , Linares Sicilia M. J. , Rodriguez-Iglesias M. A. , Pelaez T. , Shields R. K. , Garcia-Effron G. , Guinea J. , Sanguinetti M. , Turnidge J.
Published: November 2016

Method-dependent Etest epidemiological cutoff values (ECVs) are not available for susceptibility testing of eitherCandidaorAspergillusspecies with amphotericin B or echinocandins. In addition, reference caspofungin MICs forCandidaspp. are unreliable.CandidaandAspergillusspecies wild-type (WT) Etest MIC distributions (microorganisms in a species-drug combination with no detectable phenotypic resistance) were established for 4,341Candida albicans, 113C. dubliniensis, 1,683C. glabrataspecies complex (SC), 709C. krusei, 767C. parapsilosisSC, 796C. tropicalis, 1,637Aspergillus fumigatusSC, 238A. flavusSC, 321A. nigerSC, and 247A. terreusSC isolates. Etest MICs from 15 laboratories (in Argentina, Europe, Mexico, South Africa, and the United States) were pooled to establish Etest ECVs. Anidulafungin, caspofungin, micafungin, and amphotericin B ECVs (in micrograms per milliliter) encompassing ≥97.5% of the statistically modeled population were 0.016, 0.5, 0.03, and 1 forC. albicans; 0.03, 1, 0.03, and 2 forC. glabrataSC; 0.06, 1, 0.25, and 4 forC. krusei; 8, 4, 2, and 2 forC. parapsilosisSC; and 0.03, 1, 0.12, and 2 forC. tropicalis. The amphotericin B ECV was 0.25 μg/ml forC. dubliniensisand 2, 8, 2, and 16 μg/ml for the complexes ofA. fumigatus,A. flavus,A. niger, andA. terreus, respectively. While anidulafungin Etest ECVs classified 92% of theCandida fksmutants evaluated as non-WT, the performance was lower for caspofungin (75%) and micafungin (84%) cutoffs. Finally, although anidulafungin (as an echinocandin surrogate susceptibility marker) and amphotericin B ECVs should identifyCandidaandAspergillusisolates with reduced susceptibility to these agents using the Etest, these ECVs will not categorize a fungal isolate as susceptible or resistant, as breakpoints do.
pH Alkalinization by Chloroquine Suppresses Pathogenic Burkholderia Type 6 Secretion System 1 and Multinucleated Giant Cells
Authors: Chua Jennifer , Senft Jeffrey L. , Lockett Stephen J. , Brett Paul J. , Burtnick Mary N. , DeShazer David , Friedlander Arthur M.
Published: November 2016

Burkholderia mallei
and
B. pseudomallei
cause glanders and melioidosis, respectively, in humans and animals. A hallmark of pathogenesis is the formation of granulomas containing multinucleated giant cells (MNGCs) and cell death. These processes depend on type 6 secretion system 1 (T6SS-1), which is required for virulence in animals. We examined the cell biology of MNGC formation and cell death. We found that chloroquine diphosphate (CLQ), an antimalarial drug, inhibits
Burkholderia
growth, phagosomal escape, and subsequent MNGC formation. This depends on CLQ's ability to neutralize the acid pH because other alkalinizing compounds similarly inhibit escape and MNGC formation. CLQ inhibits bacterial virulence protein expression because T6SS-1 and some effectors of type 3 secretion system 3 (T3SS-3), which is also required for virulence, are expressed at acid pH. We show that acid pH upregulates the expression of Hcp1 of T6SS-1 and TssM, a protein coregulated with T6SS-1. Finally, we demonstrate that CLQ treatment of
Burkholderia
-infected Madagascar hissing cockroaches (HCs) increases their survival. This study highlights the multiple mechanisms by which CLQ inhibits growth and virulence and suggests that CLQ be further tested and considered, in conjunction with antibiotic use, for the treatment of diseases caused by
Burkholderia
.
Antibody Response to Lyme Disease Spirochetes in the Context of VlsE-Mediated Immune Evasion
Authors: Rogovskyy Artem S. , Gillis David C. , Ionov Yurij , Gerasimov Ekaterina , Zelikovsky Alex
Published: November 2016

Lyme disease (LD), the most prevalent tick-borne illness in North America, is caused byBorrelia burgdorferi. The long-term survival ofB. burgdorferispirochetes in the mammalian host is achieved though VlsE-mediated antigenic variation. It is mathematically predicted that a highly variable surface antigen prolongs bacterial infection sufficiently to exhaust the immune response directed toward invariant surface antigens. If the prediction is correct, it is expected that the antibody response toB. burgdorferiinvariant antigens will become nonprotective asB. burgdorferiinfection progresses. To test this assumption, changes in the protective efficacy of the immune response toB. burgdorferisurface antigens were monitored via a superinfection model over the course of 70 days.B. burgdorferi-infected mice were subjected to secondary challenge by heterologousB. burgdorferiat different time points postinfection (p.i.). When the infected mice were superinfected with a VlsE-deficient clone (ΔVlsE) at day 28 p.i., the active anti-B. burgdorferiimmune response did not prevent ΔVlsE-induced spirochetemia. In contrast, most mice blocked culture-detectable spirochetemia induced by wild-typeB. burgdorferi(WT), indicating that VlsE was likely the primary target of the antibody response. As theB. burgdorferiinfection further progressed, however, reversed outcomes were observed. At day 70 p.i. the host immune response to non-VlsE antigens became sufficiently potent to clear spirochetemia induced by ΔVlsE and yet failed to prevent WT-induced spirochetemia. To test if any significant changes in the anti-B. burgdorferiantibody repertoire accounted for the observed outcomes, global profiles of antibody specificities were determined. However, comparison of mimotopes revealed no major difference between day 28 and day 70 antibody repertoires.
Functional Role of MrpA in the MrpABCDEFG Na
+
/H
+
Antiporter Complex from the Archaeon Methanosarcina acetivorans
Authors: Jasso-Chávez Ricardo , Diaz-Perez César , Rodríguez-Zavala José S. , Ferry James G.
Published: November 2016

The multisubunit cation/proton antiporter 3 family, also called Mrp, is widely distributed in all three phylogenetic domains (
Eukarya
,
Bacteria
, and
Archaea
). Investigations have focused on Mrp complexes from the domain
Bacteria
to the exclusion of
Archaea
, with a consensus emerging that all seven subunits are required for Na
+
/H
+
antiport activity. The MrpA subunit from the MrpABCDEFG Na
+
/H
+
antiporter complex of the archaeon
Methanosarcina acetivorans
was produced in antiporter-deficient
Escherichia coli
strains EP432 and KNabc and biochemically characterized to determine the role of MrpA in the complex. Both strains containing MrpA grew in the presence of up to 500 mM NaCl and pH values up to 11.0 with no added NaCl. Everted vesicles from the strains containing MrpA were able to generate a NADH-dependent pH gradient (ΔpH), which was abated by the addition of monovalent cations. The apparent

K
m

values for Na
+
and Li
+
were similar and ranged from 31 to 63 mM, whereas activity was too low to determine the apparent

K
m

for K
+
. Optimum activity was obtained between pH 7.0 and 8.0. Homology molecular modeling identified two half-closed symmetry-related ion translocation channels that are linked, forming a continuous path from the cytoplasm to the periplasm, analogous to the NuoL subunit of complex I. Bioinformatics analyses revealed genes encoding homologs of MrpABCDEFG in metabolically diverse methane-producing species. Overall, the results advance the biochemical, evolutionary, and physiological understanding of Mrp complexes that extends to the domain
Archaea
.

IMPORTANCE
The work is the first reported characterization of an Mrp complex from the domain
Archaea
, specifically methanogens, for which Mrp is important for acetotrophic growth. The results show that the MrpA subunit is essential for antiport activity and, importantly, that not all seven subunits are required, which challenges current dogma for Mrp complexes from the domain
Bacteria
. A mechanism is proposed in which an MrpAD subcomplex catalyzes Na
+
/H
+
antiport independent of an MrpBCEFG subcomplex, although the activity of the former is modulated by the latter. Properties of MrpA strengthen proposals that the Mrp complex is of ancient origin and that subunits were recruited to evolve the ancestral complex I. Finally, bioinformatics analyses indicate that Mrp complexes function in diverse methanogenic pathways.
Possible complication of bee stings and a review of the cardiac effects of bee stings
Authors: Gupta Prabha Nini , Kumar B Krishna , Velappan Praveen , Sudheer M D
Published: November 2016

We report the case of a patient who, ∼3 weeks after multiple bee stings, developed a prolonged heart block, syncope and cardiac arrest. This required a temporary pacemaker to be implanted, which was later replaced with a permanent pacemaker. An ECG taken following surgery for a fractured humerus 6 years earlier was reportedly normal. The patient had been a rubber tapper who walked ∼1.5 km/day, but after the bee attack he was no longer able to walk or get up from the bed without experiencing syncope. We presume that the bee venom caused these signs, as well as the resulting heart block, which persisted long after the bee sting had subsided. Since his coronary angiogram was normal we believe he had a Kounis type involvement of the cardiovascular system, namely profound coronary spasm that caused complete heart block that did not recover. Another probable reason for the complete heart block could have been that the bees had consumed the pollen of a rhododendron flower, causing ‘grayanotoxin’ poisoning and severe heart block. The other effects of bee sting are discussed briefly.
Renal neuroendocrine tumour and synchronous pancreas metastasis: histopathological diagnosis using prostatic acid phosphatase
Authors: Kawasaki Keishi , Kawaguchi Yoshikuni , Suzuki Yoshio , Tanaka Nobutaka
Published: November 2016

A woman aged 56 years developed 2 synchronous tumours: one, 1.2 cm in diameter at the head of the pancreas; and the other, 4.0 cm in diameter, at the left side of her horseshoe kidney. Preoperative differential diagnosis of these hypovascular lesions included pancreatic ductal carcinoma (PDC) with renal metastasis, PDC with renal angiomyolipoma, renal cell carcinoma with pancreatic metastasis or PDC and renal cell carcinoma. Following pancreaticoduodenectomy and left nephrectomy, both specimens were diagnosed as grade 2 neuroendocrine tumours (NETs). Immunohistochemistry revealed that both were positive for prostatic acid phosphatase (PAP), which is specific to hindgut-derived NET, including renal NET. Accordingly, the renal tumour was diagnosed as the primary lesion, and the pancreatic tumour as a metastasis. To the best of our knowledge, this is the first report of a renal NET with a synchronous pancreas metastasis. Immunohistochemical staining for PAP was a useful diagnostic marker for synchronous NETs in the kidney and pancreas.
Chronic lead poisoning in an Iranian opium smoker resident in London
Authors: Azizi Alex , Ferguson Katie , Dluzewski Sam , Hussain Tajammul , Klein Martin
Published: November 2016

A 46-year-old man of Iranian origin presented with a 4-day history of colicky abdominal pain and absolute constipation on a background of several weeks of irritability and malaise. He had smoked 10 g of opium per week for a year and a half. On examination, he had diffuse abdominal tenderness and faecal loading. This was cleared, but the abdominal pain, nausea and vomiting persisted. He had extravascular haemolytic anaemia with punctate basophilic stippling on blood film. The patient's serum lead concentration was substantially elevated and he perhaps demonstrated Burton's line. The patient underwent chelation therapy and has recovered clinically and biochemically. Public health experts were notified and conducted an assessment of the risk to the patient and others; their lead exposure questionnaire was subsequently amended. This is an important case report of a UK resident describing lead toxicity secondary to the inhalation of opium.
Severe soft tissue infection masquerading as necrotising fasciitis in a 31-year-old woman with a background of right thigh arteriovenous malformation
Authors: Hever Pennylouise , Cavale Naveen , Harnett Paul
Published: November 2016

A 31-year-old woman with a history of a right thigh arteriovenous malformation presented with an acute history of right thigh pain and swelling. This rapidly progressed to gross sepsis. She was intubated, requiring inotropic support and renal replacement therapy. She was considered disproportionately unwell, with the impression one of necrotising fasciitis (NF). She was taken to theatre for emergency exploration and debridement. There was no evidence of NF to note in theatre. Tissue samples cultured group C Streptococcus, with histopathological examination confirming group C Streptococcal soft tissue infection. Thereafter, she was treated with high-dose intravenous antibiotics, use of a negative pressure wound therapy system, and multiple returns to theatre for repeat debridement. Her condition gradually improved, and she was stepped down to a surgical ward 3 weeks after admission. Nine weeks after initial presentation, she underwent skin grafting for wound closure. She returned to work 7 months later.
Advanced gastric cancer linitis plastica presented with disseminated intravascular coagulation
Authors: Ghazala Sehem , Bilal Jawad , Riaz Irbaz Bin
Published: November 2016

An old man was found unconscious; on admission found to have disseminated intravascular coagulation with concern of upper gastrointestinal bleed after he was found to have melena. Esophagogastroduodenoscopy on admission showed diffuse thickened gastric folds, and biopsy showed mucosal oedema. Bone marrow biopsy concerning for lymphoma was obtained showed adenocarcinoma. MRI of the abdomen was significant for diffuse gastric wall thickening. A repeat endoscopic ultrasound showed a diffuse gastric wall thickening of 15 mm and submucosal tunneling technique biopsy suggested high-grade, invasive, signet ring adenocarcinoma of the stomach. Oncology was consulted to initiate palliative chemotherapy. In retrospect, the patient was questioned regarding gastrointestinal symptoms; he reported gradual early satiety, dysphagia and unintentional weight loss over the course of 4 months.
ADDUCTOR SQUEEZE TESTING IN SOCCER: PRECISION, TORQUE PRODUCTION & IMPLICATIONS FOR SCREENING
Authors: Light N , Thorborg K
Published: November 2016

Reduced adductor strength is a known risk factor for groin injury amongst footballers. Team clinicians often test the adductor strength of players using isometric squeeze tests, performed regularly during the season to monitor fluctuations in scores. Various positions of testing are commonly used but it is not clear on which are the most reliable, stressful and ultimately capable of detecting subtle deficits in strength. In this study, three common adductor squeeze tests (long-lever, short lever in adduction and short lever-in abduction/external rotation) were investigated for differences in reliability and torque production. Using a test-retest reliability and cross-sectional comparison design, twenty professional footballers (16–33 years) without previous or current groin pain, performed a series of isometric squeeze tests measured by hand-held dynamometry. The tests were performed on two test days separated by two weeks, with both relative and absolute reliability determined, alongside torque production. Results showed no systematic variation for any of the tests, when the mean of three measures was used (ICC=0.84–0.97, MDC%=6.6–19.5). However, the least variation was observed using the long-lever position (ICC=0.97, MDC%=6.6), which also generated higher mean torque values when compared with short-lever in adduction (69%) and short lever in abduction/external rotation (11%) positions (p<0.001). In conclusion, all three tests described in this study are reliable methods of measuring adductor squeeze strength. However, long-lever squeeze testing displayed the highest adductor torque production and test-retest precision. Both of these test attributes are arguably vital for squeeze test monitoring, in order to confidently detect clinically meaningful deficits in scores that may predispose a player to subsequent injury.
THE VALIDITY OF SESSION RATINGS OF PERCEIVED EXERTION FOR MONITORING TRAINING INTENSITY DURING INDOOR ROWING: A CASE REPORT FROM AN ELITE ATHLETE IN PREPARATION FOR THE WORLD CHAMPIONSHIPS
Authors: McLaren SJ , Howse JH. , Weston M , Wright MD
Published: November 2016

Session ratings of perceived exertion (sRPE) are a popular tool for monitoring exercise intensity across a range of sports. Despite this, little is known regarding the application of sRPE to rowing ergometry. We therefore aimed to explore the validity of sRPE for monitoring training intensity during indoor rowing training. A thirty-six-year-old, female, indoor rower was monitored over a sixteen-week training period; prior to the British and World Indoor Rowing Championships (2ndplace, 30–39 year heavyweight). Rowing training could be classified as: Maximum Effort Free Stroke Rate (MaxFree; n=37), Maximum Effort Capped Stroke Rate (MaxCapped; n=9), Oxygen Utilisation 1 (UT1; n=13) and 2 (UT2; n=23), or Recovery (n=32). Throughout each training session, heart rate and a range of ergometer-derived measures were monitored continuously. Approximately 30 minutes after each training session, the athlete recorded a global sRPE (arbitrary units; AU) via the centiMax (CR100®) scale. The mean (±SD) sRPE scores for each training mode were: 75±17 for MaxFree, 64±14 for MaxCapped, 50±15 for UT1, 31±9 for UT2 and 28±14 for Recovery. The differences in sRPE between these five training modes ranged from possibly to most likely substantial. Session RPE correlations were most likely very large with mean percentage of maximal heart rate (%HRmax; r=0.83; ±90% confidence limits 0.07), very likely very large with mean 500 m split time (−0.79; ±0.08), likely very large with normalized power output (0.77; ±0.07), and possibly very large with work (kilojoules) per minute (0.72; ±0.08). Regression analysis revealed that 80% of the adjusted variance in sRPE could be explained by the combination of mean %HRmax, mean 500 m split time, normalized power output and work per minute (SEE=10 AU); with the strongest predictor variable being mean %HRmax(partial r=0.61; ±0.16, likely large). Session RPE are able to discriminate between training modes of different physiological intensities and are associated with a range of objective internal and external measures of intensity during rowing ergometry. These findings provide new evidence to support the use of sRPE as a tool for monitoring and prescribing training with indoor rowing athletes.
MUSCLE INJURIES OF THE DOMINANT OR NON-DOMINANT LEG IN MALE FOOTBALL PLAYERS AT ELITE LEVEL
Authors: Svensson K , Eckerman M , Alricsson M , Magounakis T , Werner S
Published: November 2016

Football is one of the most popular sports worldwide. Unfortunately, football players are highly exposed to injuries and muscle injuries are the most common ones. The aim was to study possible differences of muscle injuries regarding type, localization and the extent of injury between the dominant and non-dominant leg in elite male football players. Another aim was to study the injury incidence of muscle injuries of the lower extremity during match and training. Data were consecutively collected between 2007 and 2013 in a prospective cohort study based on fifty-four football players from one team of the Swedish first league. The injury incidence was calculated for both match and training and injuries to the hip adductors, quadriceps, hamstrings and triceps surae were diagnosed and evaluated with ultrasonography and their length, depth and width were measured to determine the extent of structural muscle injuries. Fifty-four players suffered totally 105 of the studied muscle injuries. Out of these 105 injuries the dominant leg was affected in 53% (n=56) of the cases. A greater extent of the injury was found in the dominant leg when compared to the non-dominant leg with regards to structural injuries of the hamstrings. No other significant differences were found. Structural hamstring muscle injuries were found to be of greater extent in the dominant leg when compared to the non-dominant leg. This new finding should be taken into consideration when allowing the football player to return to play after leg muscle injuries.
BAREFOOT PLANTAR PRESSURE MEASUREMENT IN CHRONIC EXERTIONAL COMPARTMENT SYNDROME
Authors: Roscoe D , Roberts A , Hulse D , Hughes M , Shaheen A , Bennett A
Published: November 2016

Patients with chronic exertional compartment syndrome (CECS) have pain during exercise that usually subsides at rest. Accompanying the pain, a change in gait is frequently described by patients. This typically manifests as a progressive loss of control of ankle movements, often described as ‘foot slap’. This study aimed to investigate the differences in plantar pressure between CECS cases and asymptomatic controls in a rested pre-symptomatic state. 20 men with symptoms of CECS of the anterior compartment and 20 asymptomatic controls participated. Barefoot plantar pressure was measured during walking and marching. Data was analysed to determine: stance time; foot progression angle; the mean of the medial-lateral displacement of centre of force; time from initial foot contact to initial full forefoot contact (IFFC-time); the medial-lateral distribution of pressure under the heel; and, the ratio between inner and outer metatarsal loading. Cases had shorter stance times and IFFC-times than controls. Foot progression angle was inversely related to walking speed. The area under the receiver operating curve for IFFC-time ranged from 0.746 −0.773 representing ‘fair predictive validity’. Cases have an increased rate of ankle plantarflexion after heel strike. It has recently been observed that there is almost no change in the length of the tibialis anterior muscle during the gait cycle with almost all of the changes in length of the muscle-tendon unit occurring within the tendon during walking. It follows that lowering of the foot after heel strike occurs through tendon stretch whilst the muscle contracts isometrically. Therefore if IFFC is reduced in CECS cases it is plausible that this is due to stretching of the tendon although inherent weakness in the muscle cannot be excluded. This is postulated to result from either Tibialis Anterior muscle weakness or elongation of the tendon. The observed biomechanical difference in cases may give further insight into the pathophysiology of this condition and enable further development of a non-invasive diagnostic modality. Diagnostically, the value of IFFC-time is comparable to post-exercise invasive diagnostic tests but falls short of that achieved with invasive testing during prolonged painful exercise.
BIOMECHANICAL ANALYSIS WITH OPTIMAL COMBINATION BY USING FOOT AND DISTANCE WHEN THE FUTSAL PLAYER PASSING THE BALL AGAINST THE ACCURACY OF THE TARGET
Authors: Fikri S , Pradhila F , Dirganta D
Published: November 2016

Futsal is one kind of soccer game. Recently, futsal become more popular around the world and also in Indonesia. In the futsal game, passing the ball is an important activity. However, many inaccuracies occurs when the futsal player pass the ball towards the target. Therefore, understanding the biomechanics analysis and the factors that affects the accuracy of the pass is important. The purpose of this study is to obtain the biomechanics analysis, understanding the factors that affect the accuracy of the target when futsal player pass the ball based on using the foot and the distance, and to obtain optimal combination between those factors. We performed an experiment in which 10 futsal playing men from Industrial Engineering, Universitas Indonesia to participate. Their average mass was 63±13 kg and the average height was 172±6 cm. The experiment was designed by using two-way factorial design. Each respondent was instructed to pass the ball to a target on four different conditions based on using the foot (inside foot and instep foot) and the distance (2 m and 3 m from the target). Platform 1 in AMTI Biomechanics Force Platforms BP400600H was used to collect the kinematics data from Ground Reaction Force (GRF) and Required Coefficient of Friction (RCOF). The results showed that the distance factor influences the accuracy of the pass with p-value=0.001 and the interaction between those factors by using the foot and the distance also has an effect on the GRF with p-value=0.005. The optimal combination from those factors when futsal player pass the ball by using the inside foot and the distance was 2 m with percentage of accuracy is 91±7 %. In this experiment the respondents were limited to using just one brand of futsal shoes with two different sizes. This results the compressive force and coefficient of friction forces obtained tend to be the same for every conditions. For the development of next researches, it is recommended to use more brands of shoes so that the factors mentioned before can be compared and so the optimum shoes condition on the physical performance of the player can be determined.
INTERNAL CAROTID ARTERY DISSECTION AND DELAYED STROKE FOLLOWING RUGBY TACKLE – A CASE REPORT
Authors: Cowlin D , Dickinson M , Sultan S
Published: November 2016

Following England's grand slam success in the ‘Six Nations’ tournament in 2016, publicity around the safety of rugby football is likely to be greater than ever before. Recent media coverage around players that have sustained head injuries in the context of competitive sporting events has also served to increase the awareness amongst sporting management, players and governing bodies alike. Significant head and neck injuries are thankfully rare in all contact sports. However there is always an element of risk when tough physical contact occurs between participants (either intentionally or accidental). The possible consequences of impact injuries, whilst occasional, should not be viewed as an unfortunate exception to the rule but should be used to increase and develop injury/clinical management/training strategies for all sporting levels, not just at the international end of the game. Sporting governing bodies such as the RFU (Rugby football Union) do much to minimise risk, including raising awareness of the consequence of head injuries and secondary impact syndrome, use of concussion scoring tools and removal of players from the field for formal assessment. However, these strategies are usually only utilised when players have sustained a head injury. This case study details a 36 year old male who collapsed 4 hours after competing in a rugby match. After initial diagnostic confusion, it later transpired he had suffered a middle cerebral artery thrombus, secondary to internal carotid artery dissection. This was as a consequence of a collision during a rugby match, and a suspected shearing or deceleration injury due to neck twisting during a tackle. This report will offer a unique and interesting insight into the patient's perspective of this injury – both at the time the actual stroke occurred and his subsequent rehabilitation journey. It will also discuss that whilst much publicity and training is offered around the assessment and management of head injuries and/or concussion, the possible intracerebral consequence of neck trauma sustained in contact sports seems to be less well publicised. This mechanism of injury should be considered in the emergency department as in this case the ‘typical clinical presentation’ of an extradural haematoma turned out to be something quite different.
PRE-SEASON MOTOR PERFORMANCE RELEVANT TO KNEE INJURY CONTROL IN AN ENGLISH ADULT NETBALL CLUB: A DESCRIPTIVE STUDY
Authors: Mullally EM , King CM , Davies SC , Mooney AM , Clark NC
Published: November 2016

Noncontact knee injuries are common in netball and can result in major disability and socioeconomic burden. Different types of single-leg balance (SLB) and single-leg hop (SLH) test have been widely used in a variety of knee sports medicine contexts. Knowledge of SLB and SLH test performance can help inform the clinician regarding an athlete's risk of knee injury. There is, however, a gap in the scientific literature regarding SLB and SLH test performance in adult netball players. Therefore, the purpose of this study was to describe pre-season performance of a battery of SLB and SLH tests considered clinically important in knee injury control in an English adult netball club. The Illinois Agility Test (IAT) was also performed to represent netball-related agility. After university ethics approval was obtained and informed consent completed, 23 female netball players participated (mean±standard deviation (SD): age 29±6 y; height 171.6±7.0 cm; mass 68.2±9.8 kg; defence n=10; centre n=2; attack n=11). All reported being uninjured, available for selection and registered for pre-season training. Test order was: barefoot eyes closed balance (ECB; sec), shod triple hop for distance (THD; cm), single hop for distance (SHD; cm) and vertical hop (VH; cm). Leg order was right (R), left (L). The IAT was conducted last. Practice trials and then three measured trials were performed. Appropriate between-trial rest periods were ensured. All tests have previously reported reliability. The mean of measured trials was used for descriptive statistics. All players successfully completed all tests. Mean±SD values were: ECB, R 22.5±15.8 s, L 29.6±15.5 s; THD, R 463.1±53.2 cm, L 464.6±38.7 cm; SHD, R 167.0±18.0 cm, L 166.4±15.7 cm; VH, R 20.0±3.7 cm, L 19.5±3.1 cm; IAT, 19.5±1.3 sec. Across all tests, mean data were comparable to mean data published by other research groups for females of similar age playing in other agility-focused team sports at similar levels of competition. Because the present data were comparable to data from other research groups, the present data were accepted and corroborated as a representation of the motor performances contained within each of the tests. The present and new data can, therefore, be used at several points during the knee injury control decision-making process for adult female netball players.
A STUDY OF HEAD INJURY ADVICE ON RETURN TO SPORT IN ACCIDENT AND EMERGENCY
Authors: Dhand R , Khamoo D , Eastwood D
Published: November 2016

Return to play (RTP) post head injury is a controversial yet important topic in sport. Repeated head injuries have been linked to long-term neurological conditions such as Chronic Traumatic Encephalopathy (McKee, A. et al, NEN 2008, 68 (7), 709–735). NICE Guidance states that there should be printed advice given to patients for returning to sports (www.nice.org.uk/guidance/cg176/chapter/1- recommendations#discharge-and-follow-up). International consensus guidelines indicated that elite and non-elite athletes should be managed using the same treatment and RTP model. A minimum of 48 hours rest is recommended before attempting a graduated RTP protocol. (McCrory, P.et al CJSM 2013,23(2), 89–117. Some professional bodies recommend 14 days of complete rest (http://www.englandrugby.com/mm/Document/MyRugby/Headcase/01/30/49/33/returntoplayafterconcussion_Neutral.pdf). The project aimed to assess whether RTP advice was given to patients being discharged home from Accident and Emergency (A+E) after a head injury. Firstly, head injury advice cards for all 8 trusts in the Northern Deanery were analysed for advice on RTP. Secondly, there was retrospective analysis of the notes of all A+E patients aged 18–50 who attended University Hospital of North Durham over a 6-month period, and were discharged home. 6 trusts (75%) had no information on when to RTP after a head injury. 326 patients were analysed. 49 patients (15%) attended due to a documented sporting cause. 243 patients (75%) displayed symptoms suggestive of concussion. 2 patients (0.6%) were given advice on when to RTP. Results indicate that we may be neglecting RTP advice for our patients attending A+E with a head injury. A+E departments should be encouraged to include advice on RTP for patients with emphasis on greater education for both healthcare professionals and patients. Further research is needed for the recommended rest period before RTP and the definite long-term effects of repeated head injury.