bluuebunny/crossref_metadata_2025 huggingface dataset:
A one‐step assay for sorted CD3+ cell purity and chimerism after hematopoietic stem cell transplantation
Authors: Desoutter Judith , Usureau Cédric , Jacob Valentine , Lebon Delphine , Caulier Alexis , Da Costa Cécilia , Charbonnier Amandine , Joris Magalie , Marolleau Jean‐Pierre , Guillaume Nicolas
Published: December 2020

A hematopoietic chimerism assay is the laboratory test for monitoring engraftment and quantifying the proportions of donor and recipient cells after hematopoietic stem cell transplantation recipients. Flow cytometry is the reference method for determining the purity of CD3+ cells on the chimerism of selected CD3+ cells. In the present study, we developed a single‐step procedure that combines the CD3+ purity assay (using the PCR‐based Non‐T Genomic Detection Kit from Accumol, Calgary, Canada) and the qPCR chimerism monitoring assay (the QTRACE qPCR assay from Jeta Molecular, Utrecht, the Netherlands). First, for the CD3+ purity assay, we used a PCR‐friendly protocol by changing the composition of the ready‐to‐use reaction tubes (buffer and taq polymerase) and obtained a satisfactory calibration plot (R2 = 0.8924) with a DNA reference scale of 2 ng/μl. Next, 29 samples (before and after CD3 positive selection) were analyzed, the mean cell purity was, respectively, 19.6% ± 6.45 and 98.9% ± 1.07 in the flow cytometry assay; 26.8% ± 7.63 and 98.5% ± 1.79 in the PCR‐based non‐T genomic detection assay. Our results showed that the CD3+ purity assay using a qPCR kit is a robust alternative to the flow cytometry assay and is associated with time savings when combined with a qPCR chimerism assay.
MRI T2/STIR epaxial muscle hyperintensity in some dogs with intervertebral disc extrusion corresponds to histologic patterns of muscle degeneration and inflammation
Authors: Morrison Emily J. , Baron‐Chapman Matthew L. , Chalkley Mark
Published: December 2020

Magnetic resonance imaging hyperintensity on T2‐weighted turbo SE and STIR sequences of the paraspinal musculature in canine patients being imaged for thoracolumbar intervertebral disc extrusion is frequently observed but poorly understood in veterinary medicine. The objective of this prospective analytical study was to describe the histopathology of muscle hyperintensity in dogs with thoracolumbar intervertebral disc extrusions and to determine if a relationship exists between the presence of this hyperintensity and various patient factors. Twenty privately owned dogs who underwent surgical decompression of intervertebral disc extrusions diagnosed on MRI were enrolled (10 normal “control or nonaffected cases” without MRI paraspinal musculature hyperintensity and 10 “affected cases” with hyperintensity). Surgical biopsies of the epaxial musculature at the region of hyperintensity (affecteds) and at the site of the disc herniation (controls) were submitted for histopathology. The degree of myofiber degeneration and necrosis was scored using an ordinal scoring system: absent (0), minimal (10), mild (20), moderate (30), marked/severe (40), and massive (50). Associations between hyperintensity presence and patient age, weight, body condition, neurologic status, acuteness of onset, number of disc herniation sites, degree of spinal cord compression, and volume of herniated material were investigated. Nonaffected patients were significantly older (median age = 9.4 years) than affected patients (median age = 3.5 years), but no other significant associations were found. Acute myofiber degeneration/necrosis and intramuscular inflammation were observed in half of affected patients. Therefore, T2/STIR muscle hyperintensity in some patients with intervertebral disc extrusion may represent muscle degeneration and inflammation.
Coxiella burnetii in the environment: A systematic review and critical appraisal of sampling methods
Authors: Abeykoon A. M. Hasanthi , Clark Nicholas Joshua , Soares Magalhaes Ricardo Jorge , Vincent Gemma Anne , Stevenson Mark Anthony , Firestone Simon Matthew , Wiethoelter Anke Katrin
Published: December 2020

Q fever is a zoonotic disease caused by the intracellular bacterium, Coxiella burnetii. Its primary mode of transmission is by inhalation of aerosols originating from infected animals and contaminated environments. The organism has a very low infective dose, can persist in the environment for long periods of time and large outbreaks fuelled by windborne spread have been previously reported. Detection of C. burnetii in the environment is therefore important during human and animal outbreak investigations and for the control and prevention of Q fever. This study aimed to systematically review and critically appraise the published literature on sampling methods used to detect C. burnetii from different environmental samples. A search of four electronic databases with subsequent hand searching identified 47 eligible articles published since 1935. These articles described sampling of dust, air, soil and liquids in attempts to detect C. burnetii during 19 Q fever outbreaks and in 28 endemic settings. Environmental positivity was most commonly associated with ruminant livestock populations. Evidence describing spatio‐temporal characteristics and associated geographical dispersion gradients was limited. The most commonly tested sample type was dust which also yielded the highest bacterial loads of >108 bacteria/cloth. The MD8 (Sartorius) air sampler was used widely for air sampling. Soil was the only sample type for which a validated laboratory protocol was established specifically for C. burnetii. Each environmental sample type has its advantages and limitations which are discussed in detail and a simplified framework to guide decisions around environmental sampling for C. burnetii is provided. In any type of environmental sampling, it is recommended to use standardized and validated methods and to match the most ideal sampling strategy and timing with the research context. These conditions are essential to be considered when designing future Q fever management plans that involve environmental sampling for C. burnetii.
Dreams and Realities for South Africa: Use of Official Languages Act, 2012
Authors: Mnguni Aaron
Published: December 2020

Language policies are the cornerstone that establish and maintain communication amongst people. Proper communication, particularly amongst speakers of many languages in a country such as South Africa hinges heavily on perceptions regarding the status of the languages used in that specific country. According to the Republic of South African Constitution (Act 108 of 1996), South Africa has eleven official languages. Nine of these official languages (the indigenous African languages), are regarded as historically disadvantaged, while the remaining two, viz. English and Afrikaans enjoyed official recognition under the then ‘apartheid’ era that lasted until 1994. The previously disadvantaged African languages still lag in terms of development, when compared to English and to a lesser extent, Afrikaans. To address this challenge and reverse the status quo, several measures have been undertaken by government, including the passing of an Act called, Use of Official Languages Act, 2012. This Act aims at managing the use of the official languages optimally, with special emphasis on the previously marginalised languages. South Africa is known for developing good language policies but often criticised for producing such good policies for one good purpose only - to display them in office shelves. Following this state of affairs, this article therefore examines the implementation challenges regarding this Act and suggest what could be done to successfully implement it in South Africa. Second, the article also seeks to alleviate the perceived apathy in implementing language policies, particularly in South Africa, and with implications for Africa as a whole.
Design of a Legged and Clamper-Based Capsule Robot With Active Locomotion Function
Authors: Zhang Fan , Ye Dongxu , Song Shuang
Published: December 2020

This paper presents a legged and clamper-based capsule robot (CR) with active locomotion function. The CR utilizes the extension and contraction of the anchoring legs to expand the collapsed intestinal wall, crawl in the intestinal tract, and stand in large spaces such as the stomach and large intestine organs. The mechanical structure design, kinematic analysis, principle of locomotion, and force analysis of the CR are presented. The design concept and locomotion principles of the proposed CR are verified by a prototype with the diameter of 13 mm and length of 39 mm. Three experiments were conducted to test the locomotion performance of the proposed CR. In the experiments, the prototype successfully expands the collapsed phantom intestine, stands on the plane, and moves forward in transparent tube at a promising speed. Experimental results indicate that the CR has good locomotion capabilities.
Research on Autonomous Underwater Vehicle Homing Method Based on Fuzzy-Q-FastSLAM
Authors: Dong Lingyan , Xu Hongli , Feng Xisheng , Li Ning
Published: December 2020

Autonomous docking guidance is one of the key technologies to achieve the autonomous underwater vehicle (AUV) docking with the sub-sea docking station (DS) to realize long-term resident operation. In the process of AUV docking, the combination of long-distance acoustic guidance based on acoustic sensor and terminal visual guidance based on camera is often adopted. However, affected by the accuracy of the navigation sensor and acoustic positioning sensor carried by AUV, as well as the ocean current, AUV cannot accurately know its own position and the position of the DS, resulting in a large acoustic guidance error and the inability to enter the visual guidance stage with a reasonable deviation, thus leading to the docking failure. In this article, an improved FastSLAM algorithm is proposed to estimate the position of AUV and DS simultaneously. The positioning accuracy of traditional FastSLAM algorithm is affected by such factors as the estimation accuracy of the statistical characteristics of process noise. An improved algorithm for FastSLAM based on fuzzy Q-learning is proposed. The homing path is planned based on the Dubins theory. The path is tracked by line-of-sight guidance. The results of matlab simulation and experimental data analyzing of the portable AUV are applied to verify the effectiveness of the proposed algorithm.
Validation of a Directed Energy Ignition System on a Large-Bore Single Cylinder Gas-Fueled Engine
Authors: Pommier Forrest , Lepley David , Beshouri Greg , Jacobs Timothy
Published: December 2020

The natural gas industry has seen a considerable increase in production recently as the world seeks out new sources of economical, reliable, and more environmentally friendly energy. Moving this natural gas requires a complex network of pipelines and compressors, including reciprocating engines, to keep the gas moving. Many of these engines were designed more than 40 years ago and must be retrofit with modern technologies to improve their performance while simultaneously reducing the harmful emissions that they produce. In this study a directed energy ignition system is tested on a two-stroke, single cylinder, natural gas-fired engine. Stability and emissions will be observed throughout a range of spark waveforms for a single speed and load that enables the most fuel-lean operation of the engine.

Improving the combustion process of the legacy pipeline engines is a substantial area of opportunity for reducing emissions output. One means of doing so is by improving an engines ability to operate at leaner conditions. To accomplish this, an ignition system needs to be able to send more energy to the spark plug in a controlled manner than a tradition capacitive-discharge ignition system. Controlling the energy is accomplished by optimizing the structure of the waveform or “profile” for each engine design. With this particular directed energy ignition system, spark profiles are able to be configured by changing the duration and amount of current sent to the spark plug. This study investigates a single operating speed and load for 9 different spark energy configurations. Engine operation at these test conditions will allow for emissions and engine performance data, using directed energy, to be analyzed in contrast to capacitive-discharge ignition.
Parametric Studies of a Novel Combustion Modelling Approach for Low Temperature Diesel Spray Simulation
Authors: Fang XiaoHang , Sekularac Nikola , Davy Martin H.
Published: December 2020

Conditional Source-term Estimation (CSE) is a combustion model based on the conditional moment hypothesis where transport equations for reactive species are conditionally averaged on conserved scalars. Major advantages of this strategy are the reduced spatial dependence of the conditional averages and negligible fluctuations around the conditional averages, which considerably simplify the reaction rate closure. Historically, simulations using CSE are limited to low carbon fuels (i.e. methane and hydrogen) where the reduced chemistry manifold can be constructed through techniques including intrinsic low dimensional manifolds and trajectory generated manifolds. However, the use of such strategies to create manifolds for diesel surrogates has proven problematic.

In this study, the potential of a combination of an unsteady Flamelet Generated Manifold (FGM) and the Conditional Source-term Estimation approach to predict the ignition and flame propagation on an autoigniting n-dodecane spray flame is assessed. Simulations are performed on a single-hole injection of n-dodecane under a wide range of Engine Combustion Network’s “Spray A” conditions within a Reynolds-averaged Navier-Stokes (RANS) framework. Results from parametric sweeps of ambient temperature and oxygen concentration are qualitatively validated against experimental data from the literature and compared against predictions from an industry standard well-stirred reactor model. The efficacy of the CSE-FGM RANS approach in predicting flame characteristics is evaluated and further compared with high fidelity CSE-FGM simulations using the Large Eddy Simulation (LES) turbulence model.

Overall, it was found that the CSE-FGM RANS model was able to capture global flame properties — showing particular strength in predicting auto-ignition events in the low temperature region. The model was also able to satisfactorily capture details of the two-stage ignition process. The results were shown to be consistent with those of the CSE-FGM LES model, demonstrating the adaptability of the CSE-FGM approach to different turbulence modelling paradigms.
Effect of Support Materials on Pd Methane Oxidation Catalyst Using Dynamic Estimation Method
Authors: Nitta Yoshifuru , Yamasaki Yudai
Published: December 2020

In the maritime industry, lean burn gas engines have been expected to reduce emissions such as NOx, SOx and CO2. On the other hand, the slipped methane, which is the unburned methane (CH4) emitted from lean burn gas engines have a concern for impact on global warming. It is therefore important to make a progress on the exhaust aftertreatment technologies for lean burn gas engines. As a countermeasure for the slipped methane, Palladium (Pd) catalyst for CH4 oxidation can be expected to provide one of the most feasible methods because Palladium (Pd) catalyst for CH4 oxidation can activate in the lower temperature. However, recent studies have shown that the reversible adsorption by water vapor (H2O) inhibits CH4 oxidation on the catalyst and deactivates its CH4 oxidation capacity.

It can be known that the CH4 oxidation performance is influenced by active sites on the Pd catalyst. However, measuring methods for active sites on Pd catalyst under exhaust gas conditions could not be found. Authors thus proposed a dynamic estimation method for the quantity of effective active sites on Pd catalyst in exhaust gas temperature using water-gas shift reaction between the saturated chemisorbed CO and the pulse induced H2O. The previous study clarified the relationship between adsorbed CO volume and Pd loading in gas engine exhaust gas temperature and revealed the effects of flow conditions on the estimation of adsorbed CO volume. However, in order to improve CH4 oxidation performance on Pd catalyst under exhaust gas conditions, it is important that effects of support materials on active sites should clarify.

This paper introduced experimental results of estimation of absorbed CO volume on different support materials of Pd catalysts by using the dynamic evaluation method. Experimental results show that chemisorbed CO volume on Pd/Al2O3 catalyst exhibits higher chemisorbed CO volume than that of Pd/SiO2 and Pd/Al2O3-SiO2 catalyst in 250–450 °C. These results can provide a part of the criteria for the application of Pd catalyst for reducing the slipped methane in exhaust gas of lean burn gas engines.
Validation of Species-Based Extended Coherent Flamelet Model in a Large Eddy Simulation of a Homogeneous Charge Spark Ignition Engine
Authors: See Y. , Wang M. , Bohbot J. , Colin O.
Published: December 2020

The Species-Based Extended Coherent Flamelet Model (SB-ECFM) was developed and previously validated for 3D Reynolds-Averaged Navier-Stokes (RANS) modeling of a spark-ignited gasoline direct injection engine. In this work, we seek to extend the SB-ECFM model to the large eddy simulation (LES) framework and validate the model in a homogeneous charge spark-ignited engine. In the SB-ECFM, which is a recently developed improvement of the ECFM, the progress variable is defined as a function of real species instead of tracer species. This adjustment alleviates discrepancies that may arise when the numerical treatment of real species is different than that of the tracer species. Furthermore, the species-based formulation also allows for the use of second-order numeric, which can be necessary in LES cases. The transparent combustion chamber (TCC) engine is the configuration used here for validating the SB-ECFM. It has been extensively characterized with detailed experimental measurements and the data are widely available for model benchmarking. Moreover, several of the boundary conditions leading to the engine are also measured experimentally. These measurements are used in the corresponding computational setup of LES calculations with SB-ECFM. Since the engine is spark ignited, the Imposed Stretch Spark Ignition Model (ISSIM) is utilized to model this physical process. The mesh for the current study is based on a configuration that has been validated in a previous LES study of the corresponding motored setup of the TCC engine. However, this mesh was constructed without considering the additional cells needed to sufficiently resolve the flame for the fired case. Thus, it is enhanced with value-based Adaptive Mesh Refinement (AMR) on the progress variable to better capture the flame front in the fired case. As one facet of model validation, the ensemble average of the measured cylinder pressure is compared against the LES/SB-ECFM prediction. Secondly, the predicted cycle-to-cycle variation by LES is compared with the variation measured in the experimental setup. To this end, the LES computation is required to span a sufficient number of engine cycles to provide statistical convergence to evaluate the coefficient of variation (COV) in peak cylinder pressure. Due to the higher computational cost of LES, the runtime required to compute a sufficient number of engine cycles sequentially can be intractable. The concurrent perturbation method (CPM) is deployed in this study to obtain the required number of cycles in a reasonable time frame. Lastly, previous numerical and experimental analyses of the TCC engine have shown that the flow dynamics at the time of ignition is correlated with the cycle-to-cycle variability. Hence, similar analysis is performed on the current simulation results to determine if this correlation effect is well-captured by the current modeling approach.
Assessment of Primary Atomization Models for Spray Simulation
Authors: Muthukumar Rajes Ram , Parameswaran Siva , Ge Haiwen
Published: December 2020

In the present paper, two models of primary atomization, including conventional blob injection model with a measured rate of injection profile and a one-way coupling VOF (volume of fluid) and Eulerian-Lagrangian spray model, are assessed in ECN spray A. The RNG k-ε model is used for all the simulations. A VOF method is used to simulate the nozzle flow and near nozzle spray. The results near the nozzle exit are recorded and used as the input of primary atomization in the Eulerian-Lagrangian spray model. The blob injection model and one-way coupling VOF and Eulerian-Lagrangian spray model are applied to the same evaporating and combustion spray cases. A simplified reaction mechanism for dodecane is employed in the SAGE model for combustion modeling. For the evaporating spray, liquid penetration lengths from simulations and experiments are compared. Both models well capture the measurements. The one-way coupling VOF and Eulerian-Lagrangian spray model gives slightly better agreements with the measured liquid penetration length. Additionally, its profile is smoother that is due to its much higher number of droplet parcels. For the combusting case, the CFD results are compared with available lift-off length (LOL), images of chemiluminescence and Schlieren imaging. The predicted LOLs of both models match the experimental data very well during the steady state. Relatively, the one-way coupling VOF and Eulerian-Lagrangian spray model does a better job during the early transient stage. It implies that the primary atomization model is critical for this stage. The contour plots of predicted temperature are used to compare with the results of chemiluminescence and Schlieren imaging. Good agreements are achieved for both models. The one-way coupling VOF and Eulerian-Lagrangian spray model shows better agreement with the chemiluminescence images after the end of injection. A hot-spot that is observed in chemiluminescence images is reproduced by the blob injection model. Further analysis of OH and CH2O concentration distribution shows that it is an auto-ignition site. The one-way coupling VOF and Eulerian-Lagrangian spray model does not capture this hot-spot that may be due to its more homogeneous fuel/air mixture near the spray plume that is not favorable for auto-ignition events.
Three Pattern Recognition Approaches to the Reduction of Vehicle Driving Cycles
Authors: Le Corre Samuel , Childs Thomas G. , Cary Mark , Mason Byron , Coates Barnaby
Published: December 2020

Vehicle type approval drive cycles have become a mainstay for benchmarking performance of engines in the development cycle. However, they are typically long and costly to test, with questions of repeatability and real-world relevance. With the move to Real Driving Emission (RDE) style testing, complete foreknowledge of the cycle is no longer guaranteed. This paper presents a methodology for identifying key behaviours (or information rich regions) from the current worldwide harmonised light-duty test cycle (WLTC) type approval test using a moving 2-minute window approach. Three techniques for pattern recognition are presented and applied to data collected from a modern Gasoline Turbocharged Direct Injection (GTDI) engine, run through the WLTC. The techniques examine different points in the process, with the first examining response data, and working backwards to the original vehicle speed cycle specification. The first two techniques, Intensity Ratio (IR) for cumulative responses and Energy Residency (ER) for engine inputs, are newly developed in this paper. The final technique, Dynamic Time Warping (DTW) is a new application of an existing tool to the subject of vehicle drive cycles. The techniques are examined in isolation and discussed, before being brought together to identify commonly agreed information rich sub-cycle candidates that best represent the parent cycle. The techniques make use of a combination of time windowing, signal derivative and peak analysis methods. The two-minute window is chosen based on the length of an existing sub-cycle that was identified as part of earlier work, and this method is also described and validated in this paper. One sub-cycle identified by the approach represents a duration reduction of 93% to a containable 2-minute transient. This segment accounts for 15% of the overall WLTC fuel used. A discussion of the techniques and their applications is presented to motivate future work in this area.
Accuracy Verification of 2-Dimensional Velocity Field Derived From Optical Flow With Respect to PIV Flow Field Measurement
Authors: Cui Mingli , Sun Zhe , Xu Min , Hung David , Li Xuesong
Published: December 2020

As a mature flow field measurement technology, particle image velocimetry (PIV) has been widely used to calculate the instantaneous motion of particles by identifying and comparing the positions of tracer particles between successive image frames. For example, the ambient air velocity distributions around fuel spray can be measured using LIF-PIV However, due to the need to accurately identify the tracer particles, PIV is limited in its applications, such as measuring the flow field in turbid media. Optical flow calculates apparent velocities of movement of brightness patterns in an image. Different from PIV, optical flow segments images into regions that corresponds to different objects without requirement of tracer particles. Since it is based on brightness patterns, optical flow may be widely used in measuring flow field in the area of fuel spray and in-cylinder combustion. To check the accuracy and robustness of optical flow, this study will calculate the 2-dimensional velocity fields of the same PIV image sequences using iterative optical flow and PIV respectively. Using PIV results as criterions, precision and accuracy of optical flow are studied.
Fouling Mitigation for Laser Igniters in Natural Gas Engines
Authors: Gupta Sreenath B.
Published: December 2020

Due to several recent developments in lasers and optics, laser igniters can now be designed to be (i) compact so as to have the same footprint as a standard spark plug, (ii) have low power draw, usually less than 50 Watts, and (iii) have vibration and temperature resistance at levels typical of reciprocating engines. Primary advantages of these laser igniters remain (i) extension of lean or dilution limits for ignition of combustible mixtures, and (ii) improved ignition at higher pressures.

Recently, tests performed in a 350 kW 6-cylinder stationary natural gas reciprocating engine retrofitted with these igniters showed an extension of the operational envelope to yield efficiency improvements of the order of 2.6% points while being compliant with the mandated emission regulations. Even though laser igniters offer promise, fouling of the final optical element that introduces the laser into the combustion chamber is of concern. After performing a thorough literature search, a test plan was devised to evaluate various fouling mitigation strategies. The final approach that was used is a combination of three strategies and helped sustain an optical transmissivity exceeding 98% even after 1500 hrs. of continuous engine operation at 2400 rpm. Based on the observed trend in transmissivity, it now appears that laser igniters can last up to 6000 hrs. of continuous engine operation in a stationary engine running at 1800 rpm.
Development of a Methodology for the Investigation of Residual Gases Effects on Gasoline Compression Ignition
Authors: Ravaglioli V. , Ponti F. , Silvagni G. , De Cesare M.
Published: December 2020

Compression ignited engines are still considered the most efficient and reliable technology currently available for power generation in automotive applications. In this scenario, the main obstacles to the use of conventional compression-ignited engines are the increasingly stringent emission regulations, which require significant increases in engine efficiency and severely limit both NOx and particulate matter production. As a matter of fact, the combustion process that occurs in conventional compression-ignited engines, mainly characterized by the auto-ignition of directly injected Diesel-like fuels, is a heterogeneous process usually not compatible with modern emission regulations. To overcome the mentioned critical issues, a large amount of research is being carried out to investigate the combined use of gasoline-like fuels and compression-ignited engines, which proved to be very promising to simultaneously achieve high efficiency and low emissions. One of the main critical issues related to the auto-ignition of gasoline-like fuels is the high sensitivity to the thermal conditions of the cylinder, which results in long ignition delays strongly variable with small cylinder temperature variations. This work proposes a testing methodology suitable to investigate how the residual gases trapped inside the combustion chamber affect cylinder thermal conditions and, consequently, the gasoline auto-ignition mechanisms. The testing methodology is based on a specifically designed injection control strategy that manages the cylinders independently: one cylinder is operated using a proper pattern of gasoline direct injections, while the others are operated only to vary the intake and exhaust conditions of the first cylinder, where gasoline compression ignition is studied. The testing methodology, applied to an engine installed in a test cell, proved to be effective to highlight the effect of the residual gases on gasoline auto-ignition.
Turbulence Anisotropy Investigations in an Internal Combustion Engine
Authors: MacDonald James R. , Fajardo Claudia M.
Published: December 2020

The assumption of isotropic turbulence is commonly incorporated into models of internal combustion engine (ICE) in-cylinder flows. While preliminary analysis with two-dimensional velocity data indicates that the turbulence may tend to isotropy as the piston approaches TDC, the validity of this assumption has not been fully investigated, partially due to lack of three-component velocity data in ICEs. In this work, the velocity was measured using two-dimensional, three-component (2D-3C) particle image velocimetry in a single-cylinder, motored, research engine to investigate the evolution of turbulence anisotropy throughout the compression stroke. Invariants of the Reynolds stress anisotropy tensor were calculated and visualized, through the Lumley triangle, to investigate turbulence states. Results showed the turbulence to be mostly anisotropic, with preferential tendency toward 2D axisymmetry at the beginning of the compression stroke and approaching isotropy near top-dead-center. Findings provide new insights into turbulence in dynamic, bounded flows to assist with the development of physics-based, quantitative models.
Replacement of Diesel by Biogas Generated From Wastewater Treatment in a Small Diesel Generator by Dual Fuel Technology
Authors: Dev Shouvik , Stevenson David , Butler James , Tartakovsky Boris , Guo Hongsheng , Hewko Rhonda
Published: December 2020

Canada’s remote communities experience harsh weather much of the year and run diesel generators 24 hours a day to provide heat and power. These generators utilize diesel fuel that is transported at great expense and generate greenhouse gas (GHG) and pollutant emissions. Meanwhile, remote communities produce organic wastes, such as wastewater and food wastes. Appropriate treatment of these wastes not only improves the community health and environment, but also generates certain amount of renewable fuels, such as biogas and/or syngas. Replacing diesel fuel by the renewable fuels generated from the waste treatment in the diesel generators can offset the use of diesel and also reduce GHG and pollutant emissions in remote communities.

This paper reports an application of biogas generated from wastewater treatment to replace diesel in a small diesel generator by dual fuel engine technology. With simple modification, the biogas containing 50–95% of methane was introduced into the engine intake manifold. Tests were conducted to evaluate the effects of biogas flow rate and composition on average diesel fuel consumption and emissions of carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC). The results reveal that the introduction of biogas into the engine reduced the average diesel consumption. However, the reduction of average diesel consumption with increasing biogas flow rate was not linear, possibly due to the increase in HC emissions. The introduction of biogas reduced NOx emissions but increased CO emissions. A change in the composition of biogas (methane to CO2 ratio) did not significantly affect the average diesel consumption and emissions.
Simultaneous Directed Evolution of Coupled Enzymes for Efficient Asymmetric Synthesis of
l
-Phosphinothricin
Authors: Cheng Feng , Li Qing-Hua , Zhang Hua-Yue , Wei Lan , Zhang Jia-Min , Li Ju-Mou , Xue Ya-Ping , Zheng Yu-Guo
Published: December 2020

The traditional strategy to improve multienzyme-catalyzed reaction efficiencies may lead to enhanced single-enzyme catalytic efficiencies but may also result in the loss of coordination among enzymes. We describe a directed evolution strategy for an entire coupled-enzyme system to simultaneously enhance enzyme coordination and catalytic efficiency.
Spike Glycoprotein and Host Cell Determinants of SARS-CoV-2 Entry and Cytopathic Effects
Authors: Nguyen Hanh T. , Zhang Shijian , Wang Qian , Anang Saumya , Wang Jia , Ding Haitao , Kappes John C. , Sodroski Joseph
Published: December 2020

The development of an effective and durable SARS-CoV-2 vaccine is essential for combating the growing COVID-19 pandemic. The SARS-CoV-2 spike (S) glycoprotein is the main target of neutralizing antibodies elicited during virus infection or following vaccination.
Multiplexed Competition in a Synthetic Squid Light Organ Microbiome Using Barcode-Tagged Gene Deletions
Authors: Burgos Hector L. , Burgos Emanuel F. , Steinberger Andrew J. , Suen Garret , Mandel Mark J.
Published: December 2020

Beneficial microbes play essential roles in the health and development of their hosts. However, the complexity of animal microbiomes and general genetic intractability of their symbionts have made it difficult to study the coevolved mechanisms for establishing and maintaining specificity at the microbe-animal host interface.
Oligometastatic renal cell carcinoma in the palatine tonsil: successful resection using trans-oral robotic surgery
Authors: Ross Talisa , Malik Akshat , Awad Zaid
Published: December 2020

A man in his mid 70s was referred to head and neck outpatients with bulky tissue in the left tonsillar fossa. He had previously been treated for oligometastatic renal clear cell carcinoma (diagnosed over 15 years prior to disease recurrence) by tonsillectomy and adjuvant radiotherapy (years from primary treatment), followed by trans-oral laser surgery to his oropharyngeal recurrence 3 years later. Examination under anaesthetic and biopsy confirmed further recurrence of disease in the left tonsillar fossa, with parapharyngeal extension, which has not been previously reported in the literature. After discussion in the head and neck and urology multi-disciplinary teams meeting, the patient was offered trans-oral robotic-assisted surgery (TORS) for local control and prevention of progression of a fungating oropharyngeal mass. TORS partial pharyngectomy and left buccal artery myomucosal flap reconstruction were successfully carried out, with preservation of some swallow function.
Serial anterior segment optical coherence tomography post autologous simple limbal epithelial transplantation
Authors: Kate Anahita , Shanbhag Swapna S , Goyal Ritin , Basu Sayan
Published: December 2020

A 24-year-old young man presented to us with total limbal stem cell deficiency (LSCD) in the right eye 1 year post ocular chemical burn. The patient subsequently underwent limbal biopsy in the healthy contralateral eye and autologous simple limbal epithelial transplantation in the right eye. The patient was followed up with sequential imaging of the cornea with high-resolution anterior segment optical coherence tomography (HR-ASOCT) for 3 years. The serial HR-ASOCT imaging in the operated eye showed regeneration of the epithelium from the limbal transplant over the human amniotic membrane (hAM) with integration of the transplant within the cornea with subepithelial retention of the hAM. Over the long-term follow-up, thinning of the hAM and thickening of the epithelium was noted. At 3 years, the cornea maintained an intact epithelium with no signs of recurrence of LSCD.
Paediatric bilateral femoral neck fractures in osteopetrosis treated conservatively
Authors: Kumar Saurabh , Dhammi Ish Kumar , Shahi Pratyush , Zafar Ahmer
Published: December 2020

The treatment of pathological femoral neck fracture in children due to osteopetrosis is not clear as only a few cases have been reported to date. We encountered a 7-year-old osteopetrotic girl with asynchronous bilateral femoral neck fractures. Radiographical assessment showed markedly dense bones with loss of corticomedullary differentiation, sandwich vertebrae and increased density of the ribs. Her mother had a similar radiological picture. Genetic testing showed CLCN-7 mutation which confirmed the diagnosis of autosomal dominant osteopetrosis. As the parents opted against operative treatment, the femoral neck fractures were managed conservatively with skin traction. At the 2-year follow-up, both fractures had united, although with coxa vara, and the patient had excellent functional outcome as she could walk without difficulty, had unrestricted motion at both hips, and there was no pain. Lifestyle modifications were suggested to prevent recurrent fractures and genetic counselling was done.
Long induction of tolerance to imatinib
Authors: Bojanini Leyla , Attia Steven , Heagney Haesuk , Gonzalez-Estrada Alexei
Published: December 2020

Imatinib is used to treat several haematological and solid malignancies. Cutaneous side effects could often limit the use of this medication. We present a case of a 62-year-old woman with a history of a gastrointestinal stromal tumour that developed a delayed cutaneous adverse reaction 10 days after starting imatinib 400 mg daily. She developed the same symptoms with reintroduction at a dose of 100 mg and with an alternative tyrosine kinase inhibitor, nilotinib 50 mg/day. Given that imatinib was considered her best treatment, she underwent a long induction of drug tolerance (IDT) protocol to imatinib. Patient tolerated the medication without further reactions for 6 months and had improvement of her cancer per last imaging studies. IDT should be considered in delayed hypersensitivity reactions to imatinib after a failed reintroduction of the drug or when no other equally effective agents are available.
Hepatic brucelloma: a rare complication of a common zoonotic disease
Authors: Vatidis George , Rigopoulou Eirini I , Tepetes Konstantinos , Dalekos George N
Published: December 2020

Hepatic brucelloma (HB), a rare manifestation of brucellosis, refers to liver involvement in the form of abscess. A 35-year-old woman stockbreeder was admitted due to 1-month history of evening fever, sweating and weight loss, while she was on 3-week course of rifampicin/doxycycline for suspected brucellosis. On admission, she had hepatosplenomegaly and a systolic murmur, while cholestasis, increased inflammation markers and a strong-positive Wright-Coombs test were the main laboratory findings. As blood and bone marrow cultures were unrevealing, further investigation with CT imaging showed a central liver calcification surrounded by heterogeneous hypodense area being compatible with HB. Material from CT-guided drainage tested negative forBrucellaspp. After failure to improve on a 10-week triple regiment, surgical excision was decided andBrucellaspp were identified by PCR. Our case highlights challenges in establishing HB diagnosis, which should be considered on the right epidemiological context and when serological and radiological evidence favour its diagnosis.
Influenza B associated acute necrotising encephalopathy with visual impairment in a child
Authors: Billa Ramya Deepthi , Czech Theresa , Badheka Aditya , Chegondi Madhuradhar
Published: December 2020

Influenza-associated encephalopathy/encephalitis (IAE) can result in serious neurological complications. We report a 4-year-old healthy female child with the diagnosis of IAE. Her clinical course was complicated by temporary visual impairment and significant motor deficits. Her unique ophthalmological findings have little precedent in previous literature.
Clozapine and chemotherapy: a dangerous couple or a necessary partnership?
Authors: Campbell Gillian , Wong Eugene
Published: December 2020

A 48-year-old man with a history of schizophrenia was diagnosed with B-cell lymphoma of the small bowel. Neutropaenia occurred secondary to chemotherapy, which led to clozapine being discontinued, which resulted in the deterioration of his mental state, in turn, affecting the treatment of lymphoma. Clozapine was later reintroduced alongside granulocyte colony-stimulating factor, leading to improved mental state without any further incidences of neutropaenia.
Primary intestinal follicular lymphoma presenting as multiple lymphomatous polyposis
Authors: Ng Hwei Jene , Schmigylski Rudi , Nale Krsty , Collins Patrick
Published: December 2020

Multiple lymphomatous polyposis (MLP) is a rare condition, described in the literature as a presentation of extranodal mantle cell lymphoma. We report a rare case of follicular lymphoma presenting as MLP in a young woman with a short history of haematochezia who underwent colonoscopy. Immunohistochemistry on colonic biopsies confirmed follicular lymphoma. Microscopic examination found an extensive and dense lymphoid infiltrate, which demonstrated a follicular growth pattern. The neoplastic cells were positive with BCL2, BCL6, CD10 and CD20, and were negative with CD3, CD5, Cyclin D1 and SOX11. CT staging showed disseminated lymphadenopathy and the patient was commenced on chemotherapy. Endoscopic evaluation and histopathological analysis are vital for the accurate diagnosis of MLP. Our case demonstrates that follicular lymphoma should be considered as a differential, as not all cases of diffuse colonic MLP are related to mantle cell lymphoma. This distinction must be made to provide the best clinical management for the patient.
Resection of the arch of cricoid cartilage and circumcision of the tracheal cartilage for subglottic stenosis
Authors: Masui Takashi , Uemura Hirokazu , Syugyo Masayuki , Kitahara Tadashi
Published: December 2020

Subglottic stenosis is a disease that causes dyspnoea by congenital or acquired stenosis of the cricoid cartilage and trachea. The cause of acquired subglottic stenosis varies. In this case, we present a case of idiopathic subglottic stenosis. Tracheotomies are performed in many cases, but they require long-term insertion of a tracheal cannula and make treatment difficult. In this case study, we performed a tracheoplasty by resection of the arch of cricoid cartilage and circumcision of the tracheal cartilage and implemented a cannula-free observation protocol.
Acute disseminated encephalomyelitis (ADEM) associated with COVID-19
Authors: Langley Lawrence , Zeicu Claudia , Whitton Louise , Pauls Mathilde
Published: December 2020

A 53-year-old man admitted to the critical care secondary to respiratory failure due to COVID-19 developed agitation and global hypotonia. Brain MRI revealed bilateral hyperintense lesions throughout the brain and cerebrospinal fluid identified oligoclonal bands. Intravenous high-dose glucocorticoids were administered followed by an oral tapering dose and the patient clinically improved. Acute disseminated encephalomyelitis should be considered in patients with COVID-19 who present with altered mentation and polyfocal neurological deficits.
Impact of obstetric unit closures, travel time and distance to obstetric services on maternal and neonatal outcomes in high-income countries: a systematic review
Authors: Malouf Reem Saleem , Tomlinson Claire , Henderson Jane , Opondo Charles , Brocklehurst Peter , Alderdice Fiona , Phalguni Angaja , Dretzke Janine
Published: December 2020

Objectives

To systematically review (1) The effect of obstetric unit (OU) closures on maternal and neonatal outcomes and (2) The association between travel distance/time to an OU and maternal and neonatal outcomes.

Design

Systematic review of any quantitative studies with a comparison group.

Data sources

Embase, MEDLINE, PsycINFO, Applied Social Science Index and Abstracts, Cumulative Index to Nursing and Allied Health and grey literature were searched.

Methods

Eligible studies explored the impact of closure of an OU or the effect of travel distance/time on prespecified maternal or neonatal outcomes. Only studies of women giving birth in high-income countries with universal health coverage of maternity services comparable to the UK were included. Identification of studies, extraction of data and risk of bias assessment were undertaken by at least two reviewers independently. The risk of bias checklist was based on the Cochrane Effective Practice and Organisation of Care criteria and the Newcastle-Ottawa scale. Heterogeneity across studies precluded meta-analysis and synthesis was narrative, with key findings tabulated.

Results

31 studies met the inclusion criteria. There was some evidence to suggest an increase in babies born before arrival following OU closures and/or associated with longer travel distances or time. This may be associated with an increased risk of perinatal or neonatal mortality, but this finding was not consistent across studies. Evidence on other maternal and neonatal outcomes was limited but did not suggest worse outcomes after closures or with longer travel times/distances. Interpretation of findings for some studies was hampered by concerns around how accurately exposures were measured, and/or a lack of adjustment for confounders or temporal changes.

Conclusion

It is not possible to conclude from this review whether OU closure, increased travel distances or times are associated with worse outcomes for the mother or the baby.

PROSPERO registration number

CRD42017078503.
Modelling the impact of a smallpox attack in India and influence of disease control measures
Authors: Mohanty Biswajit , Costantino Valentina , Narain Jai , Chughtai Abrar Ahmad , Das Arpita , MacIntyre C Raina
Published: December 2020

Objectives

To estimate the impact of a smallpox attack in Mumbai, India, examine the impact of case isolation and ring vaccination for epidemic containment and test the health system capacity under different scenarios with available interventions.

Setting

The research is based on Mumbai, India population.

Interventions

We tested 50%, 70%, 90% of case isolation and contacts traced and vaccinated (ring vaccination) in the susceptible, exposed, infected, recovered model and varied the start of intervention between 20, 30 and 40 days after the initial attack.

Primary and secondary outcome measures

We estimated and incorporated in the model the effect of past vaccination protection, age-specific immunosuppression and contact rates and Mumbai population age structure in modelling disease morbidity and transmission.

Results

The estimated duration of an outbreak ranged from 127 days to 8 years under different scenarios, and the number of vaccine doses needed for ring vaccination ranged from 16 813 to 8 722 400 in the best-case and worst-case scenarios, respectively. In the worst-case scenario, the available hospital beds in Mumbai would be exceeded. The impact of a smallpox epidemic may be severe in Mumbai, especially compared with high-income settings, but can be reduced with early diagnosis and rapid response, high rates of case finding and isolation and ring vaccination.

Conclusions

This study tells us that if smallpox re-emergence occurs, it may have significant health and economic impact, the extent of which will depend on the availability and delivery of interventions such as a vaccine or antiviral agent, and the capacity of case isolation and treatment. Further research on health systems requirements and capacity across the diverse states and territories of India could improve the preparedness and management strategies in the event of re-emergent smallpox or other serious emerging infections.