bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Phase Change Material Transition Temperature on the Performance of Latent Heat Storage Thermal Control in Tablet Computers
Authors: Sponagle Benjamin , Groulx Dominic , White Mary Anne
Published: September 2019

The processing power of handheld electronic devices has increased rapidly over the last decade. Modern handheld devices are thin (<9 mm) and utilize passive temperature control strategies. The combination of these factors has resulted in temperature control becoming a major obstacle to continued development. This work investigates the use of latent heat storage modules to improve the temperature control of tablet computers. Such modules store energy during periods of high heat dissipation and release it later when the device is less active. A key design aspect for these systems is identification of the appropriate phase change materials (PCMs), and specifically the optimal transition temperature. A numerical model of a tablet computer was created. Simulations with latent heat storage modules with transition temperatures between 35 and 47 °C showed that PCMs with lower transition temperatures allowed the tablet computer to operate longer without overheating. PCMs with transition temperatures between 35 and 40 °C were found to be most suitable.
Theoretical Modeling of Vapor Condensation in the Presence of Noncondensable Gas on a Horizontal Tube
Authors: Lu Junhui , Cao Haishan , Li JunMing
Published: September 2019

Double-boundary layer theory was adopted to investigate the distributions of the liquid film, gas film, heat transfer coefficient, and condensate mass fluxes around a horizontal tube for vapor condensation with noncondensable gases like steam–air and steam–CO2 mixtures under free convection. The investigation considered the effects of the noncondensable gas concentration, surface subcooling temperature, and pressure. The thicknesses of the liquid and gas films increase gradually along the wall from top to bottom, whereas the local heat transfer coefficient and the condensate mass flux decrease. The film thicknesses do not change significantly around the upper part of the tube but increase sharply around the lower part. The liquid film thicknesses, gas film thicknesses, condensate mass fluxes, and heat transfer coefficients of steam–air systems are compared with those of steam–CO2 systems. The condensate mass flux in the steam–air system is smaller than that of steam–CO2 system under the condition of the same surface subcooling and gas mass fraction because air has more moles of molecules in the mixture than CO2 and the steam more easily diffuses through CO2 than through air. The predicted average condensation heat transfer coefficients agree well with the available experimental data.
A Genetic Algorithm Based Multi-Objective Optimization of Squealer Tip Geometry in Axial Flow Turbines: A Constant Tip Gap Approach
Authors: Maral H. , Şenel C. B. , Deveci K. , Alpman E. , Kavurmacıoğlu L. , Camci Cengiz
Published: September 2019

Tip clearance is a crucial aspect of turbomachines in terms of aerodynamic and thermal performance. A gap between the blade tip surface and the stationary casing must be maintained to allow the relative motion of the blade. The leakage flow through the tip gap measurably reduces turbine performance and causes high thermal loads near the blade tip region. Several studies focused on the tip leakage flow to clarify the flow-physics in the past. The “squealer” design is one of the most common designs to reduce the adverse effects of tip leakage flow. In this paper, a genetic-algorithm-based optimization approach was applied to the conventional squealer tip design to enhance aerothermal performance. A multi-objective optimization method integrated with a meta-model was utilized to determine the optimum squealer geometry. Squealer height and width represent the design parameters which are aimed to be optimized. The objective functions for the genetic-algorithm-based optimization are the total pressure loss coefficient and Nusselt number calculated over the blade tip surface. The initial database is then enlarged iteratively using a coarse-to-fine approach to improve the prediction capability of the meta-models used. The procedure ends once the prediction errors are smaller than a prescribed level. This study indicates that squealer height and width have complex effects on the aerothermal performance, and optimization study allows to determine the optimum squealer dimensions.
Influence of Blade Flexibility on the Dynamic Response Simulation of a Turbomolecular Pump on Magnetic Bearings
Authors: Barbosa Moreira Alysson Bruno , Thouverez Fabrice
Published: September 2019

This paper proposes the simulation of a complete mechanical model of a turbomolecular pump rotor, including rotor and blades flexibility, suspended by controlled active magnetic bearings. The mechanical model is composed of an eight stage blisk, attached to a shaft. Magnetic forces are linearized by the first-order Taylor expansion around a given point. Including blades and rotor flexibility makes the mechanical system asymmetric, so the equations of motion for the coupled system have periodic terms. A modal controller was designed to control rigid body modes, since the number of sensors is limited and no state observer is implemented. PID controllers are used for low frequency modes combined with the second order filters to damp high frequency modes. First of all, stability analysis was carried out for the axisymmetric case. Second, blades flexibility was included. Forced response of the whole system to an impulsive force was studied. Divergent responses for the system in rotation were obtained as a second order filter pole possibly interacting with blades modes. Taking the second order filters off the control loop allowed the system to be stable. These results show that the analysis method developed here is efficient to evaluate the performance of a controller in closed loop with the complete flexible system. This method may be used in industrial design processes as computation times for the complete system are very short.
Sensitivity Analysis of Unsteady Corium Solidification in an Initially Emptied Horizontal Turbulent Pipe Flow
Authors: Somers-Neal Shawn , Nguyen Vien , Matida Edgar , Tang Vinh , Kaya Tarik
Published: September 2019

In a reactor core meltdown under postulated severe accidents, the molten material called corium could be ejected or relocated through existing vessel penetrations. There exists, however, a potential for plugging of melt flow due to its complete solidification providing the availability of an adequate heat sink. Simulations of the melt flow in a horizontal tube were carried out to conduct a sensitivity study on the effect of key parameters on the melt penetration distance and bulk temperature distribution of the corium. The Reynolds number was varied from 10,000 to 20,000, inlet temperature was varied from 2600 K to 3000 K, the corium thermal conductivity was varied from 10 W/m·K to 20 W/m·K, and the pipe diameter was varied from 0.0095 m to 0.019 m. In addition, a comparison was made with an analytical model based on a modified Epstein's model and a previous numerical model. The study provided insight into the lower bound, which was found to be 98 mm, and the upper bound was 258 mm when predicting the potential penetration length of corium in horizontal pipes.
A Study of Superhomogenization Applied to PHWR Lattices
Authors: Ferguson Thomas A. , Nichita Eleodor M.
Published: September 2019

To reduce computational expenses, full-core production-type neutronics calculations are customarily performed using a simplified core-model whereby large regions of the core, called nodes, are assumed to be homogeneous. The process of generating the few-group homogenized-node macroscopic cross sections is called lattice homogenization. The simplest homogenization method is standard homogenization (SH) and full-core models based on it do not usually reproduce heterogeneous-core calculations too closely. To improve agreement between node-homogenized core results and heterogeneous-core results, advanced homogenization techniques are used. Such techniques tend to use additional parameters besides homogenized macroscopic cross sections. Superhomogenization (SPH) is an advanced lattice homogenization method, which has been developed initially for light-water-reactor (LWR) lattices whereby fuel elements are arranged in a rectangular array. It has the advantage of not requiring any modification to the full-core diffusion code for its implementation. For LWRs, SPH establishes neutronic equivalence between detailed-geometry heterogeneous fuel-pin cells and homogenized fuel-pin cells by adjusting homogenized multigroup macroscopic cross sections and diffusion coefficients. This work investigates the possible use of the SPH methodology for pressurized heavy-water reactor (PHWR) lattices whose fuel pins are arranged in concentric rings rather than in a rectangular array. Results for single-node (SN) as well as multinode (MN) lattice-calculation models are presented. Results show that, with proper region definition, the SPH methodology can be used for PHWR lattices but that improvement in homogenization accuracy is only marginal compared with SH when comparing results for the same type of lattice model (SN or MN).
Rotordynamic Characteristics Prediction for Hole-Pattern Seals Using Computational Fluid Dynamics
Authors: Thorat Manish R. , Hardin James R.
Published: September 2019

The experimental setup for a hole-pattern seal is modeled using computational fluid dynamics (CFD) and results compared with measured test data and bulk flow model (ISOTSEAL) predictions. The inlet swirl boundary condition for prior CFD analyses of this test case have either been assumed or based on pitot-tube measurements. In this paper, the validity of each is investigated by including radial inlet nozzles with the inlet plenum in the model geometry. A transient mesh deformation technique with multiple frequency journal excitations is used to determine frequency-dependent rotordynamic coefficients. This multifrequency excitation method is validated against single frequency sinusoidal journal excitation. An empirical limit on the number of frequencies that can be packed in a multifrequency excitation signal to provide a reasonable estimate of rotordynamic coefficients is provided. Rotordynamic coefficients estimated using CFD compare well with measured rotordynamic coefficients. For the given test data, the ISOTSEAL bulk flow model does not provide good correlation for cross-coupled stiffness if the measured swirl ratio at the inlet of the seal is used in the prediction. However, improvement in correlation for cross-coupled stiffness is obtained if the swirl ratio found from CFD analysis is used in the bulk flow model, indicating that pitot-tube measurements of swirl may not be accurate.
Experimental Study on Thermal Contact Resistance Improvement for Optical Fiber by Using Low-Melting Temperature Alloy
Authors: Chu Wen-Xiao , Lin Hao-Yu , Wang Chi-Chuan
Published: September 2019

This paper presents an experimental analysis for minimizing the thermal contact resistance (R) between an optical fiber and copper heat sink by using the low-melting temperature alloy (LMTA) as the thermal interface material (TIM) subject to high-flux operation (up to 250 W ⋅ m−1). For the cases without LMTA, the temperature rise (ΔT) can easily surpass 195 °C at a heating load of 25 W ⋅ m−1. By contrast, ΔT is dramatically reduced to be less than 1 °C with LMTA as TIM with a much higher heating power of 150 W ⋅ m−1. The corresponding thermal resistance (R) can be reduced from 6.5–8.2 K ⋅ m ⋅ W−1 to 0.004–0.013 K ⋅ m ⋅ W−1. The improvement is far superior to existing studies. Besides, decreasing the surface roughness and increasing contact pressure also help to reduce R, especially for the cases when the LMTA is not melted. As the LMTA melts, a significant reduction of R by 56% is achieved as compared to the case without melting. The effect of surface roughness and contact pressure on the thermal contact resistance is also examined, and it is found that the influences are small once LMTA melts.
Impact of Overhead Air Supply Layout on the Thermal Performance of a Container Data Center
Authors: Chu Wen-Xiao , Wu Jui-Lin , Tsui Yeng-Yung , Wang Chi-Chuan
Published: September 2019

This study focused on the improved designs of airflow management in container data centers having overhead air supply. The computational fluid dynamics (CFD) model is first validated with experimental results. Then, the impact of grille diameter, deflector angle, and air supply layout on the data center thermal performance is investigated. The results show that the larger grille diameter may reduce the volumetric flowrate through the upstream grille, causing insufficient air supply and strong hot-air recirculation at the first rack A1. By decreasing the grille diameter from 335 mm to 235 mm, the average rack cooling index (RCI) and supply heat index (SHI) can be improved from 25.4% and 0.292 to 65% and 0.258, respectively. However, implementing small diameter grilles is not an economic way for data center performance improvement as far as the energy consumption is concerned due to the high pumping power. Meanwhile, raising the deflector angle below 30 deg in grille S1 can provide moderate improvement on temperature of the A1 rack. A further rise in the deflector to 40 deg may impose severe deterioration with a pronounced hot-spot area. The data center performance can be improved by changing from center-cold-aisle arrangement to center-hot-aisle layout. The layout provides much higher return air temperature and the RCI and SHI can be improved by 32.7% and 34.5%, respectively.
Efficiency Measurement Approach for a Hydrogen Oxyfuel Combustor
Authors: Tanneberger Tom , Schimek Sebastian , Paschereit Christian Oliver , Stathopoulos Panagiotis
Published: September 2019

Higher shares of variable renewable generation have already raised the demand for energy storage and network services in the power sector. As this trend is expected to continue, the combination of these services in a large scale will be imperative toward a carbon-free power sector. A very promising way to perform this task without any additional emissions is through stoichiometric combustion of the electrolysis products (H2 and O2) in steam and the injection of the generated steam in a conventional steam cycle. However, this can be done only if the product steam has only traces of the two reactants in it, in order to avoid damage of downstream components. The amount of residual gas in the product steam is a direct function of the combustion efficiency. This work analyzes the combustion efficiency of a H2/O2 combustor under steam dilution. As the product gas of such a combustor is primarily steam, the intended efficiency measurement is very challenging and cannot be performed with conventional methods. Instead, an in situ measurement of oxygen and hydrogen is applied. The respective diagnostics and challenges are presented along with the combustion efficiency results. Moreover, a combustor design study is carried out and different flame types (jet and swirl-stabilized flames) are compared. The initial results demonstrate that steam-diluted H2/O2 combustion can achieve an efficiency close to 100%.
Anomaly Detection in Gas Turbine Time Series by Means of Bayesian Hierarchical Models
Authors: Losi Enzo , Venturini Mauro , Manservigi Lucrezia , Ceschini Giuseppe Fabio , Bechini Giovanni
Published: September 2019

Nowadays, gas turbines (GTs) are equipped with an increasing number of sensors, of which the acquired data are used for monitoring and diagnostic purposes. Therefore, anomaly detection in sensor time series is a crucial aspect for raw data cleaning, in order to identify accurate and reliable data. To this purpose, a novel methodology based on Bayesian hierarchical models (BHMs) is proposed in this paper. The final aim is the exploitation of information held by a pool of observations from redundant sensors as knowledge base to generate statistically consistent measurements according to input data. In this manner, it is possible to simulate a “virtual” healthy sensor, also known as digital twin, to be used for sensor fault identification. The capability of the novel methodology based on BHM is assessed by using field data with two types of implanted faults, i.e., spikes and bias faults. The analyses consider different numbers of faulty sensors within the pool and different fault magnitudes. In this manner, different levels of fault severity are investigated. The results demonstrate that the new approach is successful in most fault scenarios for both spike and bias faults and provide guidelines to tune the detection criterion based on the morphology of the available data.
A Review on the Relationships Between Acoustic Emission, Friction and Wear in Mechanical Systems
Authors: Feng Peipei , Borghesani Pietro , Smith Wade A. , Randall Robert B. , Peng Zhongxiao
Published: September 2019

Acoustic emission (AE) techniques play a key role in machine condition monitoring and wear/fault diagnosis. Understanding the impact of friction and wear on the generation of AE signals is essential to building a reliable wear monitoring system. However, existing papers focus on only one or two factors in specific contact conditions. This paper aims at surveying studies related to both theoretical models and experimental investigations to produce a comprehensive picture of the relationship between tribological parameters (e.g., surface roughness, oil film thickness, and friction coefficient), operating parameters (e.g., sliding velocity and load), and AE signal characteristics (e.g., amplitude/energy, frequency, and event count). This result will provide guidance for the development of AE-based condition monitoring approaches and in particular for the establishment of AE-based wear assessment techniques.
Resistant rose cultivar affects life table parameters of two-spotted spider mite and its predators Phytoseiulus persimilis and Amblyseius swirskii (Phytoseiidae)

Authors: Alipour Zahra , Fathipour Yaghoub , Farazmand Azadeh , Khanamani Mostafa
Published: September 2019

Herbivores' host plant resistance may also affect performance of their predators. The effect of susceptible ('Yellow') and resistant ('Roulette') rose cultivars on demographic parameters of the two-spotted spider mite (TSSM), Tetranychus urticae Koch and its predators Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) was determined under laboratory conditions. The obtained data were analyzed using the two-sex life table theory. The development rate of different life stages of TSSM and its predators on the susceptible and resistant rose cultivars were signiﬁcantly different. Total development time of juvenile stages of TSSM and A. swirskii on the resistant cultivar was longer than that on the susceptible one, although no significant differences were obtained in the case of P. persimilis. By using the two-sex life table, the intrinsic rate of increase (r) of TSSM on the susceptible and resistant cultivars was 0.205 and 0.143 day-1, respectively. In addition, the net reproductive rate (R0) of TSSM on the susceptible and resistant cultivars was 26.46 and 11.47 eggs per individual, respectively; however, the mean generation time (T) of TSSM on these cultivars was 15.92 and 16.92 days, respectively. Furthermore, the value of the intrinsic rate of increase (r) in P. persimilis on the susceptible and resistant cultivars was 0.217 versus 0.163 day-1as well as in A. swirskii on the mentioned cultivars was 0.147 versus 0.117 day-1, respectively. There was no significant difference between the values of the net reproductive rate (R0) in P. persimilis on the susceptible and resistant rose cultivars, but in A. swirskii the value of this parameter on the susceptible cultivar was significantly higher than that on the resistant one. The mean generation time (T) in both predators on the resistant cultivar was longer than the susceptible one. In conclusion, resistance of the rose cultivar negatively affected the population growth parameters of TSSM and its both predators.
Albumin-chaperoned cyanine dye yields superbright NIR-II fluorophore with enhanced pharmacokinetics
Authors: Tian Rui , Zeng Qiao , Zhu Shoujun , Lau Joseph , Chandra Swati , Ertsey Robert , Hettie Kenneth S. , Teraphongphom Tarn , Hu Zhubin , Niu Gang , Kiesewetter Dale O. , Sun Haitao , Zhang Xiaodong , Antaris Alexander L. , Brooks Bernard R. , Chen Xiaoyuan
Published: September 2019

Complexation of cyanine dye with albumin produces efficient NIR-II fluorophore improving the resolution of in vivo bioimaging.
Size-dependent thermodynamic structural selection in colloidal crystallization
Authors: Pretti Evan , Zerze Hasan , Song Minseok , Ding Yajun , Mao Runfang , Mittal Jeetain
Published: September 2019

Diffusionless transformations between different crystal structures of DNA-functionalized colloids are driven by thermodynamics.
Azithromycin Protects against Zika Virus Infection by Upregulating Virus-Induced Type I and III Interferon Responses
Authors: Li Chunfeng , Zu Shulong , Deng Yong-Qiang , Li Dapei , Parvatiyar Kislay , Quanquin Natalie , Shang Jingzhe , Sun Nina , Su Jiaqi , Liu Zhenyang , Wang Min , Aliyari Saba R. , Li Xiao-Feng , Wu Aiping , Ma Feng , Shi Yi , Nielsen-Saines Karin , Jung Jae U. , Qin Frank Xiao-Feng , Qin Cheng-Feng , Cheng Genhong
Published: September 2019

Azithromycin (AZM) is a widely used antibiotic, with additional antiviral and anti-inflammatory properties that remain poorly understood. Although Zika virus (ZIKV) poses a significant threat to global health, there are currently no vaccines or effective therapeutics against it. Here, we report that AZM effectively suppresses ZIKV infection
in vitro
by targeting a late stage in the viral life cycle.
Acquisition of Class C β-Lactamase PAC-1 by Sequence Type 644 Strains of Pseudomonas aeruginosa
Authors: Bour Maxime , Fournier Damien , Jové Thomas , Pouzol Armelle , Miltgen Guillaume , Janvier Frédéric , Jeannot Katy , Plésiat Patrick
Published: September 2019

Four sequence type 664 (ST664) (serotype O:5) strains of
Pseudomonas aeruginosa
that were highly resistant to antibiotics, including ceftolozane-tazobactam and ceftazidime-avibactam, but were susceptible to colistin were found to harbor the gene encoding the rare class C β-lactamase PAC-1 on a chromosomally located Tn
1721
-like transposon. The
bla
PAC-1
gene was associated with the 16S rRNA methylase determinant
rmtF2
, which confers pan-aminoglycoside resistance.
CTX-M-33 Is a CTX-M-15 Derivative Conferring Reduced Susceptibility to Carbapenems
Authors: Poirel Laurent , de la Rosa José-Manuel Ortiz , Richard Anaïs , Aires-de-Sousa Marta , Nordmann Patrice
Published: September 2019

CTX-M-type extended-spectrum β-lactamases (ESBLs) are widespread among
Enterobacterales
strains worldwide. The most common variant is CTX-M-15, which hydrolyzes ceftazidime at a high rate but spares carbapenems. Here, we identified CTX-M-33, a point mutation derivative of CTX-M-15 (Asp to Ser substitution at Ambler position 109) that exhibited low carbapenemase activity.
West Nile Virus Infection Blocks Inflammatory Response and T Cell Costimulatory Capacity of Human Monocyte-Derived Dendritic Cells
Authors: Zimmerman Matthew G. , Bowen James R. , McDonald Circe E. , Pulendran Bali , Suthar Mehul S.
Published: September 2019

West Nile virus (WNV) is an encephalitic flavivirus that remains endemic in the United States. Previous studies have found dysfunctional T cell responses correlate to severe disease outcomes during human WNV infection. Here, we sought to better understand the ability of WNV to program human dendritic cells (DCs) to prime WNV-specific T cell responses. While productive infection of monocyte-derived DCs activated antiviral and type I interferon responses, molecules associated with inflammation and programming of T cells were minimally induced. Functionally, WNV-infected DCs dampened T cell activation and proliferation during an allogeneic response. Combined, our data support a model whereby WNV infection of human DCs compromises WNV-specific T cell immunity.
The 3.1-Angstrom Cryo-electron Microscopy Structure of the Porcine Epidemic Diarrhea Virus Spike Protein in the Prefusion Conformation
Authors: Wrapp Daniel , McLellan Jason S.
Published: September 2019

Coronavirus spike proteins are large, densely glycosylated macromolecular machines that mediate receptor binding and membrane fusion to facilitate entry into host cells. This report describes the atomic-resolution structure of the spike protein from porcine epidemic diarrhea virus, a pathogenic alphacoronavirus that causes severe agricultural damage. The structure reveals a novel position for the sialic acid-binding attachment domain in the intact spike. We also observed shed fusion-suppressive capping subunits that displayed the putative receptor-binding domain in an accessible conformation. These observations provide a basis for understanding the molecular mechanisms that drive the earliest stages of alphacoronavirus infection and will inform future efforts to rationally design vaccines.
A Puzzling Anomaly in the 4-Mer Composition of the Giant Pandoravirus Genomes Reveals a Stringent New Evolutionary Selection Process
Authors: Poirot Olivier , Jeudy Sandra , Abergel Chantal , Claverie Jean-Michel
Published: September 2019

Recent years have seen the discovery of several families of giant DNA viruses infecting the ubiquitous amoebozoa of the genus
Acanthamoeba
. With double-stranded DNA (dsDNA) genomes reaching 2.5 Mb in length packaged in oblate particles the size of a bacterium, the pandoraviruses are currently the most complex and largest viruses known. In addition to their spectacular dimensions, the pandoraviruses encode the largest proportion of proteins without homologs in other organisms, which is thought to result from a
de novo
gene creation process. While using comparative genomics to investigate the evolutionary forces responsible for the emergence of such an unusual giant virus family, we discovered a unique bias in the tetranucleotide composition of the pandoravirus genomes that can result only from an undescribed evolutionary process not encountered in any other microorganism.
Myelomatous pleural effusion and extensive extraskeletal soft tissue involvement: a rare presentation of clonal plasma cell disorders
Authors: Alexander Vijay , Binu Aditya John , Sathyendra Sowmya
Published: September 2019

A 65-year-old woman presented with a history of progressive dyspnoea, left pleuritic pain, loss of weight and appetite. Previous history was significant for pulmonary tuberculosis diagnosed 10 years before. Physical examination revealed a left supraclavicular soft tissue mass with absent breath sounds over the left hemithorax. Investigations revealed hypercalcemia with albumin:globulin reversal. The bone marrow biopsy was consistent with the diagnosis of multiple myeloma (IgG). Pleural fluid analysis revealed an exudative effusion; cytology showed mature plasma cells and plasmablasts. Serum electrophoresis revealed an M band in the gamma region. Biopsy of the supraclavicular mass revealed plasma cells which were CD 138+ with Kappa light chain restriction. She was initiated on chemotherapy and is currently doing well. Myelomatous pleural effusion is a rare presentation of multiple myeloma.
Gastrointestinal lymphoma: the new mimic
Authors: Shirwaikar Thomas Anusha , Schwartz Mary , Quigley Eamonn
Published: September 2019

Background

Gastrointestinal (GI) lymphomas comprise a group of distinct clinicopathological entities of B- or T- cell type, with primary gastrointestinal Hodgkin lymphoma being extremely uncommon. The GI tract is the predominant site of extranodal non-Hodgkin lymphoma accounting for 30–40% of all extranodal lymphomas. In the Western world, the stomach is the most commonly involved site followed by the small bowel. Several chronic inflammatory and immune-mediated disorders which predispose to accelerated cell turnover may lead to the malignant transformation of gut lymphocytes and ultimately manifest as GI lymphoma. The challenge for the clinical gastroenterologist is that these tumors may have varied presentations, ranging from nonspecific symptoms such as dyspepsia or bloating to abdominal pain, nausea, vomiting, GI bleeding, diarrhea, weight loss or bowel obstruction.

Objective

We illustrate the range of presentations of GI lymphoma with examples based on consecutive cases evaluated at our institution over a 6-month period. These cases demonstrate how appropriately directed endoscopic evaluation with biopsies has the potential to provide a definitive diagnosis and allow the patient to proceed to definitive therapy.

Conclusions

The GI tract is the most commonly involved site for extranodal lymphoma with the stomach being most frequently involved organ.ChronicHelicobacter pyloriinfection, celiac disease, inflammatory bowel disease and autoimmune disorders may predispose to GI lymphoma. This heterogenous group of diseases has varied presentations that may mimic several other GI clinico-pathologic entities. GI lymphomas may be diagnosed with appropriately directed endoscopic evaluation coupled with generous tissue sampling and expert pathologic assessment. Management may range from antibiotic therapy, in the case ofHelicobacter pylori-associated gastric MALT lymphoma, to chemotherapy with or without radiation and, in rare instances, surgery. There are presently no guidelines to direct endoscopic surveillance of GI lymphomas following treatment.
Use of standardised patients for healthcare quality research in low- and middle-income countries
Authors: Kwan Ada , Daniels Benjamin , Bergkvist Sofi , Das Veena , Pai Madhukar , Das Jishnu
Published: September 2019

The use of standardised patients (SPs)—people recruited from the local community to present the same case to multiple providers in a blinded fashion—is increasingly used to measure the quality of care in low-income and middle-income countries. Encouraged by the growing interest in the SP method, and based on our experience of conducting SP studies, we present a conceptual framework for research designs and surveys that use this methodology. We accompany the conceptual framework with specific examples, drawn from our experience with SP studies in low-income and middle-income contexts, including China, India, Kenya and South Africa, to highlight the versatility of the method and illustrate the ongoing challenges. A toolkit and manual for implementing SP studies is included as a companion piece in the online supplement.
Evaluating the impact of cycle helmet use on severe traumatic brain injury and death in a national cohort of over 11000 pedal cyclists: a retrospective study from the NHS England Trauma Audit and Research Network dataset
Authors: Dodds Nick , Johnson Rowena , Walton Benjamin , Bouamra Omar , Yates David , Lecky Fiona Elizabeth , Thompson Julian
Published: September 2019

Objectives

In the last 10 years there has been a significant increase in cycle traffic in the UK, with an associated increase in the overall number of cycling injuries. Despite this, and the significant media, political and public health debate into this issue, there remains an absence of studies from the UK assessing the impact of helmet use on rates of serious injury presenting to the National Health Service (NHS) in cyclists.

Setting

The NHS England Trauma Audit and Research Network (TARN) Database was interrogated to identify all adult (≥16 years) patients presenting to hospital with cycling-related major injuries, during a period from 14 March 2012 to 30 September 2017 (the last date for which a validated dataset was available).

Participants

11 192 patients met inclusion criteria. Data on the use of cycling helmets were available in 6621 patients.

Outcome measures

TARN injury descriptors were used to compare patterns of injury, care and mortality in helmeted versus non-helmeted cohorts.

Results

Data on cycle helmet use were available for 6621 of the 11 192 cycle-related injuries entered onto the TARN Database in the 66 months of this study (93 excluded as not pedal cyclists). There was a significantly higher crude 30-day mortality in un-helmeted cyclists 5.6% (4.8%–6.6%) versus helmeted cyclists 1.8% (1.4%–2.2%) (p<0.001). Cycle helmet use was also associated with a reduction in severe traumatic brain injury (TBI) 19.1% (780, 18.0%–20.4%) versus 47.6% (1211, 45.6%–49.5%) (p<0.001), intensive care unit requirement 19.6% (797, 18.4%–20.8%) versus 27.1% (691, 25.4%–28.9%) (p<0.001) and neurosurgical intervention 2.5% (103, 2.1%–3.1%) versus 8.5% (217, 7.5%–9.7%) (p<0.001). There was a statistically significant increase in chest, spinal, upper and lower limb injury in the helmeted group in comparison to the un-helmeted group (all p<0.001), though in a subsequent analysis of these anatomical injury patterns, those cyclists wearing helmets were still found to have lower rates of TBI. In reviewing TARN injury codes for specific TBI and facial injuries, there was a highly significant decrease in rates of impact injury between cyclists wearing helmets and those not.

Conclusions

This study suggests that there is a significant correlation between use of cycle helmets and reduction in adjusted mortality and morbidity associated with TBI and facial injury.
The effect of primary care availability on antibiotic consumption in Hungary: a population based panel study using unfilled general practices
Authors: Biro Aniko , Elek Peter
Published: September 2019

Objective

We analyse the effect of primary care availability on antibiotic consumption and on the quality of antibiotic prescribing behaviour.

Design

Retrospective panel design, secondary analysis of settlement-level administrative panel data (n=2320 settlements, T=72 months).

Participants and setting

We analyse antibiotic consumption of the population of villages in Hungary, over years 2010 to 2015. We exploit the geographical and time variation in unfilled (mainly single-handed) general practices as a source of exogenous variation in the availability of primary care. We control for socioeconomic characteristics and settlement fixed effects in a panel regression framework.

Outcome measures

Antibiotic expenditures and days of therapy (DOT); consumption of narrow-spectrum and broad-spectrum antibiotics; consumption of Access, Watch and Reserve antibiotics according to the AWaRe categorisation; number of visits to the general practitioner (GP).

Results

If the general practice of a village becomes unfilled, the number of GP visits decreases on average by 9.3% (95% CI 5.6% to 12.9%), antibiotics DOT decrease on average by 3.2% (95% CI 1.0% to 5.4%) and expenditures on antibiotics decrease on average by 2.5% (95% CI 0.3% to 4.7%). The negative effect on antibiotic consumption is stronger in settlements where secondary care is less available, and where antibiotics were previously overprescribed. The quality of prescribing behaviour measured by the relative changes in the narrow-spectrum vs broad-spectrum as well as the Access versus Watch and Reserve antibiotics deteriorates significantly as a consequence of worse primary care availability.

Conclusions

Limited availability of primary care reduces the consumption of antibiotics and at the same time impairs the quality of prescriptions through a decrease of the number of doctor-patient encounters.
Community-based exercise for health promotion and secondary cancer prevention in Canada: protocol for a hybrid effectiveness-implementation study
Authors: McNeely Margaret L , Sellar Christopher , Williamson Tanya , Shea-Budgell Melissa , Joy Anil Abraham , Lau Harold Y , Easaw Jacob C , Murtha Albert D , Vallance Jeffrey , Courneya Kerry , Mackey John R , Parliament Matthew , Culos-Reed Nicole
Published: September 2019

Introduction

Cancer care has expanded from a disease-focused, survival-oriented model to an approach that now considers how survivors can live well in the aftermath of intensive therapy, where they may deal with significant changes to their bodies, mental health or emotional well-being. Research evidence supports the benefit of exercise during and following cancer treatments for cancer-related symptoms, physical functioning and fitness, and health-related quality of life. To move this efficacy evidence into practice, we designed and launched a 5-year study to evaluate the relative benefit from implementing a clinic-to-community-based cancer and exercise model of care.

Methods and analysis

A hybrid effectiveness and implementation trial design is being used to evaluate the effectiveness of delivery of community-based exercise and to collect data on implementation of the programme. The study opened in January 2017, with estimated completion by January 2022. The programme will be delivered in seven cities across the province of Alberta, Canada, with sites including three academic institutions, six YMCA locations, Wellspring Edmonton and Calgary, and six municipal fitness centres. Participants are adult cancer survivors (n=2500) from all tumour groups and stages and at any time point along their cancer treatment trajectory, up to 3 years post treatment completion. Survivors take part in a minimum of 60 min of mild-to-moderate intensity full body exercise twice weekly for a 12-week period. The primary effectiveness outcome is the proportion of participants meeting or exceeding 150 min of moderate intensity exercise per week at 1-year follow-up. The Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework will be utilised to capture individual-level and organizational-level impact of the exercise programme at 12 and 24 weeks and 1-year follow-up. The cohort of survivors participating in the study will allow for long-term (>5-year) evaluation of rates of cancer recurrence and secondary cancers beyond the funding period.

Ethics and dissemination

The study was approved by the Health Research Ethics Board of Alberta. The study is funded by Alberta Innovates and the Alberta Cancer Foundation. The study will help to answer critical questions on the effectiveness of cancer-specific community-based exercise programming in both the short-term and the long-term. Collectively, the findings will help to inform the acceptability, adoption, feasibility, reach and sustainability of community-based exercise.

Trial registration number

NCT02984163; Pre-results.
Effects of physical exercise during pregnancy on mothers’ and neonates’ health: a protocol for an umbrella review of systematic reviews and meta-analysis of randomised controlled trials
Authors: Sanabria-Martínez Gema , Poyatos-León Raquel , Notario-Pacheco Blanca , Álvarez-Bueno Celia , Cavero-Redondo Iván , Martinez-Vizcaino Vicente
Published: September 2019

Introduction

A growing interest has emerged on the effects of exercise during gestation. Several systematic reviews and meta-analyses have shown that prenatal exercise could reduce the mothers’ risk for some disorders. Despite this, evidence regarding the risk of caesarean section, birth weight or Apgar score at delivery is still controversial. Furthermore, practitioners are reluctant to recommend exercise to pregnant women suffering from some disorders, such as hypertension, pre-eclampsia or pregnant women with obesity. Moreover, the scarcity of studies addressing the risks and benefits of exercise at higher intensity prevent practitioners from recommending it at higher dosages. Umbrella reviews represent an appropriate design to elucidate the reasons behind the contradictory findings of previous systematic reviews.

Methods

This protocol was developed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols and the Cochrane Collaboration Handbook. Medline, EMBASE, Web of Science, Cochrane database of systematic reviews, Epistemonikos, Prospero register and SPORTDiscuss databases will be searched to identify systematic reviews, meta-analyses and randomised controlled trials that examine the effect of exercise on pregnancy outcomes from inception to August 2019. Searches will be conducted from September to November 2019.

Statistical analysis

Methodological quality will be evaluated using the AMSTAR 2 tool. The certainty of evidence and strength of recommendations for meta-analyses will be assessed by the Grading of Recommendations Assessment, Development and Evaluation framework. The summary effect sizes will be calculated through the use of random-effects and fixed-effects models. Heterogeneity among studies will be assessed using the I2statistic, and evidence of excess significance bias and evidence of small study effects will also be evaluated.

Ethics and dissemination

Ethical approval will not be needed for this review protocol. The results will be disseminated to academic audiences by peer-reviewed publications. Furthermore, results will be disseminated to clinical audiences through professionals’ associations and social networks, and may influence guidelines developers in order to improve outcomes in mothers and offspring.

PROSPERO registration number

CRD42019123410.
Promoting low-flow anaesthesia and volatile anaesthetic agent choice
Authors: Carter Louise A , Oyewole Molola , Bates Eleanor , Sherratt Kate
Published: September 2019

Background

As doctors, we are increasingly aware of the financial implications of our practice. The need to work in a more conscientious, efficacious and cost-effective manner is greater than ever before. Environmental and financial benefits can be seen through employing the use of low-flow anaesthesia.

Aims

This quality improvement project aimed to make anaesthetic practice more environmentally friendly and to reduce departmental spending. This could be achieved by promoting the use of low-flow anaesthesia and by encouraging isoflurane use where appropriate.

Methods

All anaesthetic consultants and trainees were invited to fill out an initial questionnaire relating to their personal preferences and practices when conducting anaesthesia. There were specific questions relating to low-flow anaesthesia and isoflurane use. Our main measure of improvement was any decrease in the number of bottles of volatile agent ordered by the department from pharmacy. Monthly spot audits were conducted to assess gas flow rates and volatile agent use in theatre. Departmental spending figures relating to the purchase of volatile agent bottles were obtained from pharmacy. Information was then disseminated to anaesthetists on a monthly basis via a ‘low-flow board’, which showed pictorial and graphical representations of differing gas flows and volatile agent usage in relation to cost.

Results

Our project showed a trend for the increased use of low-flow anaesthesia within the department. We also showed a decrease in the number of bottles of volatile agent ordered: 18% fewer bottles ordered compared with the same period the previous year. This represented a 25% decrease in total departmental expenditure on volatile agents despite an increase in theatre activity.

Conclusion

Increasing awareness regarding anaesthetic choices and promoting low-flow anaesthesia and isoflurane use, translated into an overall decreased departmental spend on volatile agents without affecting patient care.
Investigating the use of ultrasonography for the antenatal diagnosis of structural congenital anomalies in low-income and middle-income countries: systematic review protocol
Authors: Goley Stephanie Michele , Sakula-Barry Sidonie , Kelly Ann , Wright Naomi
Published: September 2019

Introduction

Congenital anomalies are the fifth leading cause of mortality in children under 5 years globally. The greatest burden is faced by those in developing countries, where over 95% of deaths occur. Many of these deaths may have been preventable through antenatal diagnosis and early intervention. This study aims to conduct a systematic review that investigates the use of antenatal ultrasound to diagnose congenital anomalies and improve the health outcomes of infants in low-income and middle-income countries (LMICs).

Methods and analysis

A systematic literature review will be conducted using three search strings: (1) structural congenital anomalies, (2) LMICs and (3) antenatal diagnosis. Four electronic databases will be searched: MEDLINE, Embase, PubMed and the Cochrane Library. Title, abstract and full-text screening will be undertaken in duplicate by two reviewers independently using Covidence. Consensus will be sought from the wider authorship for discrepancies. Data extraction will be undertaken by the principal investigator. The primary analysis will focus on the availability and effectiveness of antenatal ultrasound for structural congenital anomalies. Secondary outcomes will include neonatal morbidity and mortality, termination rates and referral rates for further antenatal care. Descriptive statistics and a narrative synthesis will be included in the final report. The methodological quality of the included studies will be evaluated using the Cochrane-approved Risk of Bias for Non-Randomised Studies of Intervention and Risk of Bias in Randomised Trials V.2.0 tools.

Ethics and dissemination

Ethical approval is not required for conducting the systematic review as there will be no direct collection of data from individuals. The results will be submitted for publication in a scientific journal and presented internationally.

Conclusion

This is the first study, to our knowledge, to systematically review current literature on the use of antenatal ultrasound for the detection of congenital anomalies in LMICs. This is vital to define current practice, highlight global disparities and evaluate effects on health outcomes for infants in low-resource settings.

PROSPERO registration number

CRD42019105620.
Transversus abdominis plane block and intrathecal morphine use in cesarean section: a retrospective review
Authors: Cole Jacob , Hughey Scott , Longwell Jason
Published: September 2019

Objectives

Cesarean delivery is an extremely common surgical procedure practiced worldwide. It is an open abdominal surgery, and is associated with significant postoperative pain. One modality that helps alleviate this pain is the transversus abdominis plane (TAP) block. This analysis sought to evaluate postoperative pain when this block was used in conjunction with intrathecal morphine.

Methods

A retrospective review was performed of 142 patients who underwent cesarean section at our institution. Of those, 43 patients had a TAP block performed. The primary outcome for this analysis was the time to first opioid administration following discharge from the operating room. Secondary outcomes included differences in postoperative pain scores, and overall opioid consumption.

Results

The average time to first opioid use postoperatively decreased in the TAP group when compared with the No-TAP group, 23.3 versus 12.1, respectively (difference of 48.2% (95% CI 74.0% to 24.3%); p<0.001) and opioid consumption was significantly decreased within the first 24 hours following surgery from 4.55 intravenous morphine equivalents (IVME) to 2.67 IVME, respectively (difference of 107.1% (95% CI 145.1% to 69.2%); p=0.006). Visual analog pain scores were significantly decreased in the TAP group versus the No-TAP group up to 36 hours postoperatively.

Conclusions

TAP blocks performed in conjunction with intrathecal morphine may decrease opioid use in the first 24 hours and improve pain scores for at least 36 hours following cesarean section. Because of the favorable safety profile, TAP blocks may contribute meaningfully to multimodal anesthesia for cesarean sections.