bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the Effect of Process Parameters and Scan Strategy During Laser Forming of Thin Open Celled Aluminium Foam
Authors: Raza Mohammad Shahid , Srinu Talari , Datta Susmita , Saha Partha
Published: September 2018

The present study provides detailed investigation on the effect of various laser processing parameters and scan strategy during laser forming of thin open-celled aluminium foam. Previous research on laser bending showed that metal foams can be formed by laser processing, but it is very difficult to form the metal foams mechanically owing to their brittle nature. The 2D Laser forming operation was carried out using 2 kW fiber laser with laser power and scanning speed as input process parameters while bending angle was calculated as an output parameter. The effect of laser power, scan speed, number of scans and scan distance from the edge on bending angle of the foam were analyzed and presented. It was observed that the laser processing showed a decrease in bending angle with an increase in scan speed except for 1750 W power, where after 12500 mm/min the bending angle did not follow the trend. The bending angle decreased with increase in number of scans probably due to strain hardening effect. The effect of scan distance from the edge was different for lower process parameter combinations {600 W, 2500 mm/min} and {1000 W, 4000 mm/min}, where the bending angle was maximum for a distance of 20 mm from edge in 1400 W, 7500 mm/min scan speed. For 1750W, 11000 mm/min bending angle was maximum for 80 mm distance from edge. The SEM analysis showed that the major concern associated with laser forming of open-celled Aluminium foam is foam melting. EDS and XRD analysis showed that formation of different oxides and compounds of Aluminium increases with increases in laser power and scan speed. Micro-Computed Tomography (micro-CT) analysis confirmed the absence of crack during laser forming and the pore density variation during laser forming was clearly visible between laser processed zone and the parent material zone.
Regional Manufacturing Cost Structures and Supply Chain Considerations for Medium Voltage Silicon Carbide Power Applications
Authors: Reese Samantha , Mann Margaret , Remo Timothy , Horowitz Kelsey
Published: September 2018

Bottoms-up cost analysis has been a mainstay of commoditized industry and manufacturing processes for years, however a holistic objective supply chain analysis to inform research and investment in the development of early stage technologies has not. The potential for rapid adoption of wide bandgap (WBG) semiconductors, specifically silicon carbide (SiC), highlights a need to understand the drivers of location-specific manufacturing cost, global supply chains, and plant location decisions. Further, ongoing research and investment, necessitates analytical analysis to help inform the roadmap of SiC technologies. In collaboration with PowerAmerica the project explores the bottoms-up cost analysis of wafers, devices, modules, and variable frequency motor drives at the anticipated manufacturing levels. Leveraging these models, it outlines how the cost reduction potential of proposed research advances can be quantified.
An Approach to Complete Product Definition Using STEP in Cloud Manufacturing
Authors: Wardhani Rivai , Liu Chao , Mubarok Khamdi , Xu Xun
Published: September 2018

The advancement of various product development technologies is contributing to a total integrated manufacturing process. And model-based design (MBD) is a key enabler for such a total integration. The current MBD approach still does not support retaining of information needed at different stages of a product lifecycle. Collaboration among different Computer Aided Design (CAD) systems still becomes an issue due to the different proprietary data format. This research provides a consolidated approach to complete product definition based on STEP AP242 neutral data format using general notes data structure. To validate and demonstrate the solution, the approach is instantiated in P21 design file and implemented in cloud manufacturing as a case study.
Design, Manufacturing, and Characterization of a Pneumatically-Actuated Soft Hand
Authors: Zhao Longchao , Gupta Satyandra K.
Published: September 2018

Soft robotic hands can be used to manipulate delicate parts. The use of under-actuated fingers can significantly reduce the number of actuators and the complexity of the hand structure. This in turn can lower the cost of realizing robotic hands. This paper presents a new design for a multi-fingered soft hand for robotic applications. We adapt the fusible core molding process to realize complex inner cavities needed in pneumatically-actuated fingers. We also introduce a method for predicting the finger motion using pseudo-rigid-body model. We demonstrate that the soft hand can achieve the desired shapes and apply the required forces in tasks such as handling, grasping, pinching, clipping, and fastening.
On the Comparison Between a Liquid Jet and a Droplet Train
Authors: Mitchell B. R. , Klewicki J. , Shwaery G. , Korkolis Y. P. , Kinsey B. L.
Published: September 2018

The surface normal impingement of a cylindrical liquid jet emanating from a nozzle is of use in numerous technological applications (e.g.., waterjet cutting). If a greater distance between the nozzle and the impingement surface is allowed, then the initially continuous liquid jet may fragment into a train of discrete droplets, whose peak impact force can exceed that of an unbroken continuous liquid jet. The present study experimentally investigates the force imparted by these two distinctly different processes for identical flow conditions (i.e., velocity, jet diameter, etc.). Based on the conservation of momentum, a justification for the significantly higher peak forces observed in the droplet train case is presented.
Characterization of Material Transfer in Friction Stir Processing With a Consumable Tool
Authors: Miller Scott
Published: September 2018

This is a study of material transfer from a consumable tool to a substrate. The major advantage of this technique is material adheres by mechanical bonding at relatively low temperature, with potential benefits of high bonding strength, low temperature and thermal effects, high tolerance to contamination, environmentally benign, and low cost of materials, tooling, and process. There is an increasing need for dissimilar material surfacing and coating applications, leading to the study of the friction surfacing process. Friction surfacing experiments were done for depositing different materials to a steel substrate. Subsequent surface roughness and material analysis was done to characterize the nature of material transfer and adhesion to the substrate. The results suggest that friction stir processing by a consumable tool is capable of producing a smooth coating with good metallurgical properties.
Model Guided Mixing of Ceramic Powders With Graded Particle Sizes in Binder Jetting Additive Manufacturing
Authors: Du Wenchao , Ren Xiaorui , Chen Yexiao , Ma Chao , Radovic Miladin , Pei Zhijian
Published: September 2018

Binder jetting additive manufacturing is a promising technology for fabricating ceramic parts with complex or customized geometries. However, this process is limited by the relatively low density of the fabricated parts even after sintering. This paper reports a study on effects of mixing powders with graded particle sizes on the powder bed packing density and consequently the sintered density. For the first time, a linear packing model, which can predict the packing density of mixed powders, has been used to guide the selection of particle sizes and fractions of constituent powders. A selection process was constructed to obtain the maximum mixed packing density. In the part of model validation, three types of alumina powders with average sizes of 2 μm, 10 μm, and 70 μm, respectively, were mixed in optimum volumetric fractions that could lead to the maximum packing density based on model predictions. Powder bed packing density was measured on binary mixtures, ternary mixture, and each constituent powders. Furthermore, disk-shaped samples were made, using binder jetting additive manufacturing, from each constituent and mixed powder. Results show that binary and ternary mixtures have higher powder bed packing densities and sintered densities than the corresponding constituent powders. The disks made from the ternary mixture achieved the highest sintered density of 65.5%.
Robotic Surface Finishing of Curved Surfaces: Real-Time Identification of Surface Profile and Control
Authors: Wen Yalun , Pagilla Prabhakar R.
Published: September 2018

An efficient strategy for robotic surface finishing of curved surfaces that includes real-time identification of the surface profile, control, and implementation is presented in this paper. Real-time identification of the surface profile in the robot base frame is accomplished by employing a proximity laser sensor mounted on the robot end-effector. This surface profile description allows us to generate trajectories for both motion and force control as it provides the surface normal at each point of the surface. Using the surface profile, a trajectory is generated that would orient the surface finishing tool to the local normal of the surface. An algorithm for simultaneous position and force control is developed for surface finishing of curved surfaces. The integrated robotic surface finishing system consists of a UR5 robot and a custom end-effector that includes a force/torque sensor, an electromechanical sander, and the proximity laser sensor. Robot Operating System (ROS) is utilized for real-time implementation, which would enable easy migration of the developed tools if other industrial robots are used. The effectiveness of the strategy is evaluated by conducting a number of experiments for flat and curved surfaces. A representative sample of results on force regulation and surface finishing are presented and discussed.
Augmented Reality System Calibration for Assembly Support With the Microsoft HoloLens
Authors: Radkowski Rafael , Kanunganti Sravya
Published: September 2018

The Microsoft HoloLens is the latest augmented reality (AR) capable head-mounted-display (HMD) with the potential to leverage AR applications in manufacturing and design. Its optical system and the embedded tracking capability are superior to many precursor HMDs and mitigate several known obstacles such as size, massive weight, visual quality, and tracking latency. Especially the last one, the not-noticeable tracking latency, is a convincing factor for people outside an AR community. Along with its onboard tracking, it allows the HoloLens to populate the physical world with virtual objects and to maintain their position while the user is moving. Although these capabilities are already convincing, the majority of applications in assembly and design require a precise alignment of virtual objects with physical parts. Especially, if a user moves the majority of components in an application situation, thus, virtual information need to move along with the physical part to convey them semantically correct. Object tracking and automatic registration are required to establish this functionality. This paper introduces an AR system which integrates an external range camera-based tracking system and the HoloLens. It incorporates two calibration procedures, which are required to register virtual 3D objects with physical components. This AR system can be used for different visualization tasks along the product life-cycle, spanning the range from training to decision making, although our major area is currently manual assembly.
Design of a Flexure-Based Active Fixture System for Precision Robotic Deburring
Authors: Beck Jacob , Sencer Burak , Balasubramanian Ravi , Meader Jordan
Published: September 2018

This paper presents on the design, prototyping and testing of a flexure-based active workpiece fixture system for precision robotic deburring. Current industrial robotic manipulators suffer from poor positioning accuracy, which makes precision tasks such as deburring, polishing and grinding challenging. Together, the robotic manipulator and the proposed active work fixture will create a dual-stage positioning system for precision tasks where position/force control is crucial. The main application is robotic deburring, which demands positioning accuracy and high compliance over large cutting forces. This first prototype active fixture system is designed as a planar motion table that is supported by parallel flexures, driven by voice-coil actuators, and uses high-resolution laser displacement pickups facilitate accurate motion generation with great backdrivability for force control. The theory behind the proposed design is shown, and a prototype is then used to validate performance. Overall the prototype flexure stage achieves a total stroke of 1 mm and a bandwidth of 21 Hz.
Grinding Wheel Motion and Force During Plaque Removal by Rotational Atherectomy in Angulated Coronary Artery
Authors: Zheng Yihao , Lyu Jingxuan , Liu Yang , Lo Jason , Susamaz Ata , Gurm Hitinder S. , Shih Albert J.
Published: September 2018

Rotational atherectomy (RA) utilizes a high-speed diamond grinding wheel to remove the calcified atherosclerotic plaque off the vessel wall via a catheter inside an artery for blood flow restoration and treatment of cardiovascular diseases. RA in angulated lesions is challenging due to the geometric constrains on the wheel motion, potentially leading to vessel dissection and perforation. To understand the grinding wheel motion and force during RA in curved arteries, experiments were conducted based on 3D printed anatomically accurate coronary artery phantoms with plaster coating as the plaque surrogate, a high-speed camera, and a multi-axis force transducer. Results showed that the grinding wheel did not orbit inside right coronary artery phantom which led to a highly biased ground region aligned with several contact points between the guidewire and the arterial wall. The grinding wheel orbital motion facilitated an even treatment of several segments in left anterior descending coronary artery phantom. The grinding force, ranging from 0.05 to 0.20 N, increased with the wheel rotational speed when the wheel orbited and was insensitive to the wheel speed without wheel orbital motion. This study explained the clinically observed guidewire bias from the engineering perspective and further revealed the RA mechanism of action in angulated artery, which may assist to improve the device design and the operating technique.
Thermal-Mechanical Numerical Modeling of the Friction Element Welding Process
Authors: Varma Ankit , Absar Saheem , Zhao Xin , Choi Hongseok , Abke Tim , Skovron Jamie D. , Ruszkiewicz Brandt J. , Mears Laine
Published: September 2018

To improve the fuel economy, the automobile industry is vigorously shifting towards using a mix of lightweight materials which offers high strength-to-weight ratio. Dissimilar material joining is of critical importance in this area. Friction element welding (FEW) has been proposed for dissimilar materials, with the capability of joining high strength materials of varying thickness in minimal time with low input energy. A coupled thermal-mechanical finite element model is developed in this work to better understand the physical mechanisms involved in the process and predict the evolution of parameters such as temperature, stress, material flow, and weld quality. The Coupled Eulerian-Lagrangian (CEL) approach is adopted to capture the severe plastic deformation of both the tool and the workpiece. The material deformation and temperature evolution are analyzed at different steps, and good agreement are shown between the simulation results and the experimental data.
Evaluating Tensile Properties of 3D Printed Continuous Fiber Reinforced Nylon 6 Nanocomposites
Authors: Liu Zhihui , Shi Jing , Wang Yachao
Published: September 2018

3D printing (additive manufacturing) has become a popular method to create three-dimensional objects due to its high efficiency and is easy to operate. 3D printing of continuous fiber reinforced polymers has been a challenge. The fused deposition modeling (FDM) processes for this purpose were proposed and made possible only several years ago. The 3D printed continuous fiber reinforced polymers are able to improve the mechanical properties by leaps and bounds. In this paper, we aim to investigate the possibility of further improve the mechanical properties of 3D printed continuous fiber reinforced polymers by adding nano fillers to the polymer matrix. In experiment, the Kevlar fiber is chosen to be the continuous fiber material, and nylon 6 (PA 6) is chosen to be the polymer matrix material. Carbon nanotubes (CNTs) and graphene nano platelets (GNPs) nanoparticles are first mixed with nylon 6 pellets to make nanocomposites. The nanocomposites are then extruded into filaments for 3D printing. During the 3D printing process, both Kevlar filament and nanocomposite filament are fed through the printing nozzle and deposited on the platform. Tensile specimens are made from pure PA 6 and four types of nanocomposites, namely, 0.1wt% CNT/PA 6, 1wt% CNT/PA 6, 0.1wt% GNP/PA 6, 1wt% GNP/PA 6. By incorporating four layers of Kevlar fiber, which leads to the weight percentage of about 9% for Kevlar fiber in materials, fiber composite tensile specimens are made from Kevlar/PA 6 composite and four fiber reinforced nanocomposites, namely, Kevlar/0.1%CNT/PA 6, Kevlar/1%CNT/PA 6, Kevlar/0.1%GNP/PA 6, and Kevlar/1%GNP/PA 6. The tensile tests reveal that CNTs filled PA 6 nanocomposites show less significant improvements in mechanical properties as compared to the GNP filled PA 6. With only 0.1wt% of GNP, the tensile modulus improves by 101%, and with 1wt% of GNP, the modulus improves by 153%. The results also indicate that although Kevlar fibers dominate the main mechanical properties of the printed composite materials, the existence of GNP nano fillers also provide noticeable contribution to the enhancement of tensile strengths and moduli, while the effect of CNTs is much less pronounced.
Mask Video Projection Based Stereolithography With Continuous Resin Flow to Build Digital Models in Minutes
Authors: Li Xiangjia , Mao Huachao , Pan Yayue , Chen Yong
Published: September 2018

The mask image projection based stereolithography (MIP-SL) is a low cost and high-resolution additive manufacturing (AM) process. However, the slow speed of part separation and resin refilling is the primary bottleneck that limits the fabrication speed of the MIP-SL process. In addition, the stair steeping effect due to the layer-based fabrication process limits the surface quality of built parts. To address the critical issues in the MIP-SL process related to resin refilling and layer-based fabrication, we present a mask video projection based stereolithography (MVP-SL) process with continuous resin flow and light exposure. The newly developed AM process enables the continuous fabrication of three-dimensional (3D) objects with ultra-high fabrication speed. In the paper. The system design to achieve mask video projection and the process settings to achieve ultrafast fabrication speed are presented. The relationship between process parameters and the surface quality of the fabricated parts is discussed. Test results illustrate the MVP-SL process with continuous resin flow can build three-dimensional objects within minutes and the surface quality of the fabricated objects can be significantly improved.
Engineered systems to study the synergistic signaling between integrin-mediated mechanotransduction and growth factors (Review)
Authors: Monteiro A. Isabela , Kollmetz Tarek , Malmström Jenny
Published: September 2018

While tremendous leaps in knowledge into cellular signaling and control have been achieved over the last few decades, there is still more to learn in how different signaling pathways act synergistically. A better understanding and control of cells in vitro and in vivo is important to enable more successful and safe applications of tissue engineering and stem cell therapy. This review is focused on two central ways cells sense their surroundings, namely, integrin-mediated mechanotransduction and growth factor signaling. Specifically, the authors explore how engineered interfaces have been applied to learn more about these processes, and how these important signaling pathways interact synergistically.
Single Nucleotide Polymorphism Genotyping Analysis Shows That Vaccination Can Limit the Number and Diversity of Recombinant Progeny of Infectious Laryngotracheitis Viruses from the United States
Authors: Loncoman Carlos A. , Hartley Carol A. , Coppo Mauricio J. C. , Browning Glenn F. , Beltrán Gabriela , Riblet Sylva , Freitas Carolina O. , García Maricarmen , Devlin Joanne M.
Published: September 2018

Recombination allows alphaherpesviruses to evolve over time and become more virulent. Historically, characterization of viral vaccines in poultry have mainly focused on limiting clinical disease, rather than limiting virus replication, but such approaches can allow field viruses to persist and evolve in vaccinated populations. In this study, we vaccinated chickens withGallid alphaherpesvirus 1vaccines that are commercially available in the United States and then performed coinoculations with two field strains of virus to measure the ability of the vaccines to prevent field strains from replicating and recombining. We found that vaccination reduced viral replication, recombination, and diversity compared to those in unvaccinated chickens, although the extent to which this occurred differed between vaccines. We suggest that characterization of vaccines could include studies to examine the ability of vaccines to reduce viral recombination in order to limit the rise of new virulent field strains due to recombination, especially for those vaccines that are known not to prevent viral replication following challenge.
Alanine, a Novel Growth Substrate for the Acetogenic Bacterium Acetobacterium woodii
Authors: Dönig Judith , Müller Volker
Published: September 2018

Peptides and amino acids are widespread in nature, but there are only a few reports that demonstrated use of amino acids as carbon and energy sources by acetogenic bacteria, a central and important group in the anaerobic food web. Our finding that
A. woodii
can perform alanine oxidation coupled to reduction of carbon dioxide not only increases the number of substrates that can be used by this model acetogen but also raises the possibility that other acetogens may also be able to use alanine. Indeed, the alanine genes are also present in at least two more acetogens, for which growth on alanine has not been reported so far. Alanine may be a promising substrate for industrial fermentations, since acid formation goes along with the production of a base (NH
3
) and pH regulation is a minor issue.
Role and Function of Class III LitR, a Photosensor Homolog from Burkholderia multivorans
Authors: Sumi Satoru , Shiratori-Takano Hatsumi , Ueda Kenji , Takano Hideaki
Published: September 2018

Members of the LitR/CarH family are adenosyl B
12
-based photosensory transcriptional regulator involved in light-inducible carotenoid production in nonphototrophic bacteria. Our study provides the first evidence of the involvement of a class III LitR, which lacks an adenosyl B
12
-binding domain in the light response of
Burkholderia multivorans
belonging to betaproteobacteria. Our biochemical analysis suggests that class III LitR protein exhibits features as a photosensor including absorption of light at the UV-A region (λ
max
= ca. 340 nm), photocyclic response, and light-dependent dissociation. This suggests that class III LitR associates with a UV-A-absorbing molecule, and it has a photosensing mechanism distinguishable from that of the B
12
-based type.
DNA Methylation by Restriction Modification Systems Affects the Global Transcriptome Profile in Borrelia burgdorferi
Authors: Casselli Timothy , Tourand Yvonne , Scheidegger Adam , Arnold William K. , Proulx Anna , Stevenson Brian , Brissette Catherine A.
Published: September 2018

Lyme disease is the most prevalent vector-borne disease in North America and is classified by the Centers for Disease Control and Prevention (CDC) as an emerging infectious disease with an expanding geographical area of occurrence. Previous studies have shown that the causative bacterium,
Borrelia burgdorferi
, methylates its genome using restriction modification systems that enable the distinction from foreign DNA. Although much research has focused on the regulation of gene expression in
B. burgdorferi
, the effect of DNA methylation on gene regulation has not been evaluated. The current study characterizes the patterns of DNA methylation by restriction modification systems in
B. burgdorferi
and evaluates the resulting effects on gene regulation in this important pathogen.
The Di-iron RIC Protein (YtfE) of Escherichia coli Interacts with the DNA-Binding Protein from Starved Cells (Dps) To Diminish RIC Protein-Mediated Redox Stress
Authors: Silva Liliana S. O. , Baptista Joana M. , Batley Charlotte , Andrews Simon C. , Saraiva Lígia M.
Published: September 2018

The mammalian immune system produces reactive oxygen and nitrogen species that kill bacterial pathogens by damaging key cellular components, such as lipids, DNA, and proteins. However, bacteria possess detoxifying and repair systems that mitigate these deleterious effects. The
Escherichia coli
RIC (repair of iron clusters) protein is a di-iron hemerythrin-like protein that repairs stress-damaged iron-sulfur clusters.
E. coli
Dps is an iron storage protein of the ferritin superfamily with DNA-binding capacity that protects cells from oxidative stress. This work shows that the
E. coli
RIC and Dps proteins interact in a fashion that counters RIC protein-induced reactive oxygen species (ROS). Altogether, we provide evidence for the formation of a new bacterial protein complex and reveal a novel contribution for Dps in bacterial redox stress protection.
Getting Our Fingers on the Pulse of Slow-Growing Bacteria in Hard-To-Reach Places
Authors: Gallagher Tara , Phan Joann , Whiteson Katrine
Published: September 2018

Chronic infections with slow-growing pathogens have plagued humans throughout history. However, assessing the identities and growth rates of bacteria in an infection has remained an elusive goal.
Evaluation of the Revised Ceftaroline Disk Diffusion Breakpoints When Testing a Challenge Collection of Methicillin-Resistant Staphylococcus aureus Isolates
Authors: Sader Helio S. , Rhomberg Paul R. , Doyle Timothy B. , Flamm Robert K. , Mendes Rodrigo E.
Published: September 2018

We assessed ceftaroline disk diffusion breakpoints for
Staphylococcus aureus
when applying revised Clinical and Laboratory Standards Institute (CLSI) ceftaroline MIC breakpoints. Disk-MIC correlation was evaluated by testing a challenge collection (
n
= 158) of methicillin-resistant
S. aureus
(MRSA) isolates composed of 106 randomly selected isolates plus 52 isolates with decreased susceptibility to ceftaroline (MIC, 1 to 16 μg/ml).
A Novel Sensitive Immunoassay Targeting the 5-Methylthio-
d
-Xylofuranose–Lipoarabinomannan Epitope Meets the WHO's Performance Target for Tuberculosis Diagnosis
Authors: Sigal George B. , Pinter Abraham , Lowary Todd L. , Kawasaki Masanori , Li Andra , Mathew Anu , Tsionsky Michael , Zheng Ruixiang Blake , Plisova Tatiana , Shen Ke , Katsuragi Kiyonori , Choudhary Alok , Honnen William J. , Nahid Payam , Denkinger Claudia M. , Broger Tobias
Published: September 2018

The only currently commercialized point-of-care assay for tuberculosis (TB) that measures lipoarabinomannan (LAM) in urine (Alere LF-LAM) has insufficient sensitivity. We evaluated the potential of 100 novel monoclonal antibody pairs targeting a variety of LAM epitopes on a sensitive electrochemiluminescence platform to improve the diagnostic accuracy.
Epstein-Barr Virus-Positive Cancers Show Altered B-Cell Clonality
Authors: Selitsky Sara R. , Marron David , Mose Lisle E. , Parker Joel S. , Dittmer Dirk P.
Published: September 2018

Around 20% of human cancers are associated with viruses. Epstein-Barr virus (EBV) contributes to gastric cancer, nasopharyngeal carcinoma, and certain lymphomas, but its role in other cancer types remains controversial. We assessed the prevalence of EBV in RNA-seq from 32 tumor types in the Cancer Genome Atlas Project (TCGA) and found EBV to be present in >5% of samples in 12 tumor types. EBV infects epithelial cells and B cells and in B cells causes proliferation. We hypothesized that the low expression of EBV in most of the tumor types was due to infiltration of B cells into the tumor. The increase in B-cell abundance and diversity in subjects where EBV was detected in the tumors strengthens this hypothesis. Overall, we found that EBV was associated with an increased and altered immune response. This result is not evidence of causality, but a potential novel biomarker for tumor immune status.
Primary tonsillar tuberculosis
Authors: Sasikumar Swetha , Ayub Irfan Ismail , Kannan Senthil , Swaminathan Rajendiran
Published: September 2018

Upper aerodigestive tract involvement with tuberculosis is relatively rare and may be seen in up to 2% of patients with pulmonary tuberculosis. Isolated tonsil involvement with tuberculosis is not commonly seen in clinical practice. We report a case of a 22-year-old postpartum mother who presented with odynophagia, fever, loss of weight and submandibular swelling of 3 months’ duration. Clinical examination revealed a submandibular node, and oropharyngeal examination revealed necrotic slough overlying an enlarged left tonsil. Fine-needle aspiration cytology of the node and histopathological examination of the left tonsillectomy specimen revealed necrotising epithelioid cell granulomas, and stain for acid-fast bacilli was positive in the latter. She was diagnosed with tonsillar tuberculosis and was started on antituberculous treatment following which she improved clinically. This case serves to demonstrate an uncommon presentation of primary tuberculosis and reminds us to consider tuberculosis also as a microbiological aetiology for tonsillitis.
Mast cell deposition and activation may be a new explanation for epiploic appendagitis
Authors: Weinstock Leonard B. , Kaleem Zahid , Selby Dale , Afrin Lawrence B
Published: September 2018

Epiploic appendagitis is as an acute painful condition of the fat on the outside of the intestine. Thus far, there have been no publications to our knowledge that appendagitis can be caused by mast cells or can be associated with chronic pain. A patient with multisystemic disorders suffered with both chronic and acute attacks of abdominal pain for a year. The worst attack led to surgical resection of an enlarged sigmoid colon epiploic appendage. Careful review of her complex medical history and mast cell stains of gastrointestinal biopsies led to the diagnosis of mast cell activation syndrome. Re-examination of the resected appendage using an immunohistochemical stain demonstrated a high mast cell density which is a new histopathological finding. Treatment of mast cell activation syndrome and other related syndromes led to marked improvement in her health, including all types of chronic abdominal pain.
Effect of intravitreal triamcinolone acetonide injection at the end of vitrectomy for vitreous haemorrhage related to proliferative diabetic retinopathy
Authors: Takamura Yoshihiro , Shimura Masahiko , Katome Takashi , Someya Hideaki , Sugimoto Masahiko , Hirano Takao , Sakamoto Taiji , Gozawa Makoto , Matsumura Takehiro , Inatani Masaru
Published: September 2018

Background/Aims

To investigate whether intravitreal injection of triamcinolone acetonide (IVTA) combined with vitrectomy prevents postoperative inflammation in patients with vitreous haemorrhage (VH) due to proliferative diabetic retinopathy (PDR).

Methods

This prospective, multicentre, randomised study conducted at seven sites in Japan enrolled patients diagnosed as having VH following PDR. Patients underwent vitrectomy with (IVTA+VIT group) or without (VIT group) IVTA at the end of the surgery. Anterior flare intensity (AFI), central retinal thickness (CRT), best-corrected visual acuity (BCVA) and intraocular pressure (IOP) were measured before and at 3 days, 1 week, 1, 3 and 6 months after surgery and compared.

Results

Number of patients who completed 6 months of follow-up was 40 and 41 in VIT group and IVTA+VIT group, respectively. AFI was significantly higher in the VIT group than in the IVTA+VIT group at 3 days (P=0.033), 1 week (P=0.019) and 1 month (P=0.037). There were no significant differences in CRT, BCVA and IOP between the groups through the observational periods. In the cases with macular oedema >350 µm of CRT at 3 days, CRT was significantly lower in the IVTA+VIT group than in the VIT group at 1 month (P=0.041).

Conclusions

IVTA combined with vitrectomy and cataract surgery contributed to inhibit the postoperative inflammation in patients with VH due to PDR. The effect of IVTA in the reduction of diabetic macular oedema may be limited to the early stage after surgery.

Trial registration number

UMIN000020376, Post-results.
Elastin modulation and modification by homocysteine: a key factor in the pathogenesis of Pseudoexfoliation syndrome?
Authors: Rebecca Manohar , Gayathri Ramakrishnan , Bhuvanasundar Renganathan , Sripriya Krishnamoorthy , Shantha Balekudaru , Angayarkanni Narayanasamy
Published: September 2018

Background

Pseudoexfoliation syndrome (PXF) is an idiopathic, elastogenesis-associated systemic disease characterised by amyloid-like material aggregates in the eye. Elevated plasma and aqueous humour (aqH) homocysteine (Hcy) is reportedly associated with PXF. This study is aimed to probe Hcy-mediated alterations in elastin expression.

Methodology

Lens level of Hcy (total Hcy (tHcy)), mRNA expression of Eln, CBS and MTR in lens capsule, protein expression of elastin in aqH were estimated by enzyme immunoassay, quantitative PCR and western blot, respectively in PXF, PXF with glaucoma (PXF-G) cases, in comparison with cataract-alone disease controls. Human lens epithelial cells (hLECs) were exposed to Hcy and homocysteine thiolactone (HCTL) to evaluate elastin expression in vitro. Furthermore, elastin recombinant protein was incubated with Hcy and HCTL to assess secondary and tertiary structural modifications based on circular dichroism spectroscopy, spectrophotometric and SEM studies.

Results

The lens tHcy was significantly high in PXF (p=0.02) and PXF-G (p=0.009). Eln expression was elevated in PXF and PXF-G (p=0.0007). Elastin level in aqH was elevated in PXF (p=0.01) and PXF-G (p=0.002). Hcy (200 µM) and HCTL (1 µM) promoted elastin expression at mRNA level by 36-fold (p=0.02) and 10-fold (p=0.05), respectively, and at protein level by nearly two-fold in cultured hLECs. Secondary structure changes in elastin protein caused by Hcy were evident from 34.11% drop in α-helix and 6.17% gain in β-sheet. Fluorescence, spectral assays and SEM analyses showed aggregation and amyloid formation of elastin with homocysteinylation.

Conclusion

The study reveals that lens accumulation of Hcy associated with hyperhomocysteinaemia is characteristic of PXF that augments elastin expression. Hcy causes structural changes promoting elastin aggregation, thereby contributing to defective elastin in PXF and PXF-G.
Effects of refresher training on the use of manual vacuum aspiration in the treatment of incomplete abortions: a quasi-experimental study in Malawi
Authors: Odland Maria Lisa , Membe-Gadama Gladys , Kafulafula Ursula , Jacobsen Geir Wenberg , Odland Jon Øyvind , Darj Elisabeth
Published: September 2018

Introduction

The maternal mortality ratio is decreasing globally, although it remains high in Malawi. Unsafe abortion is a major cause and treatment of complications after abortion is a big burden on the health system. Even though manual vacuum aspiration (MVA) is the recommended surgical treatment of incomplete abortions in the first trimester, many hospitals in Malawi continue to use sharp curettage. It is known to have more complications and is more expensive in the long run. The purpose of this study was to determine the effectiveness of a structured MVA training programme in the treatment of incomplete abortions in Malawi.

Methods

A quasi-experimental before-and-after study design was employed in an MVA training programme for health personnel at three hospitals in Southern Malawi. A total of 53 health personnel at the Queen Elizabeth Central Hospital and the district hospitals of Chikwawa and Chiradzulu (intervention hospitals) were trained in the use of MVA. Kamuzu Central Hospital in Lilongwe and the Thyolo District Hospital served as control institutions. Medical files for all women treated for an incomplete abortion at the study hospitals were reviewed before and after the intervention. Information on demographic and obstetric data and the type of treatment was collected.

Results

There was a significant increase in the use of MVA from 7.8% (95% CI 5.8 to 10.3) to 29.1% (95% CI 25.9 to 32.5) 1 year after the intervention. In comparison, we found a mere 3% increase in the control hospitals.

Conclusions

By providing a refresher training programme to health personnel who treat women with incomplete abortions, it was possible to increase the use of MVA as recommended in the Malawi national guidelines.
AIDS Therapy Evaluation in the Netherlands (ATHENA) national observational HIV cohort: cohort profile
Authors: Boender Tamara Sonia , Smit Colette , Sighem Ard van , Bezemer Daniela , Ester Catriona J , Zaheri Sima , Wit Ferdinand W N M , Reiss Peter
Published: September 2018

Purpose

In 1998, the AIDS Therapy Evaluation in the Netherlands (ATHENA) national observational HIV cohort was established to demonstrate the lifesaving effectiveness of triple combination antiretroviral therapy, including HIV-protease inhibitors, that had recently been made available for clinical use. Subsequently, the HIV Monitoring Foundation was established by the Dutch Ministry of Health, Welfare and Sport to continue ATHENA as an open cohort in order to continue the registration and monitoring of all HIV-positive people as an integral part of HIV care in all 26 HIV treatment centres in the Netherlands.

Participants

To date, a total of 25 036 participants have been enrolled in the cohort, with 263 600 person-years of follow-up. As of 1 January 2017, 19 035 HIV-1-positive participants were known to be in care: 18 824 adults (81% men and 19% women) and 211 children (47% boys and 53% girls). The remaining 6001 participants had either died (46%), were lost to care (29%) or had moved abroad (25%).

Findings to date

Today, with over 20 years of follow-up, the ATHENA cohort has provided extensive knowledge on HIV treatment, comorbidities and coinfections and created insight into the transmission dynamics of the HIV epidemic.

Future plans

ATHENA continues to enrol and monitor HIV positive people entering HIV care in the Netherlands. Future research will continue to provide tangible input into HIV care and prevention policies in the Netherlands and internationally.
Pilot randomised controlled trial to improve hand hygiene through mindful moments
Authors: Gilmartin Heather , Saint Sanjay , Rogers Mary , Winter Suzanne , Snyder Ashley , Quinn Martha , Chopra Vineet
Published: September 2018

Background

To evaluate the effectiveness of a brief mindfulness intervention on hand hygiene performance and mindful attention for inpatient physician teams.

Design

A pilot, pre-test/post-test randomised controlled mixed methods trial.

Setting

One academic medical centre in the USA.

Participants

Four internal medicine physician teams consisting of one attending, one resident, two to three interns and up to four medical students.

Intervention

A facilitated, group-based educational discussion on how mindfulness, as practised through mindful hand hygiene, may improve clinical care and practices in the hospital setting.

Main outcomes and measures

The primary outcome was hand hygiene adherence (percentage) for each patient encounter. Other outcomes were observable mindful moments and mindful attention, measured using the Mindfulness Attention Awareness Scale, from baseline to post-intervention, and qualitative evaluation of the intervention.

Results

For attending physicians, hand hygiene adherence increased 14.1% in the intervention group compared with a decrease of 5.7% in the controls (P=0.035). For residents, the comparable figures were 24.7% (intervention) versus 0.2% (control) (P=0.064). For interns, adherence increased 10.0% with the intervention versus 4.2% in the controls (P=0.007). For medical students, adherence improved more in the control group (4.7% intervention vs 7.7% controls; P=0.003). An increase in mindfulness behaviours was observed for the intervention group (3.7%) versus controls (0.9%) (P=0.021). Self-reported mindful attention did not change (P=0.865).

Conclusions

A brief, education-based mindfulness intervention improved hand hygiene in attending physicians and residents, but not in medical students. The intervention was well-received, increased mindfulness practice, and appears to be a feasible way to introduce mindfulness in the clinical setting. Future work instructing clinicians in mindfulness to improve hand hygiene may prove valuable.

Trial registration number

NCT03165799; Results.
Gut microbiota relationships to lung function and adult asthma phenotype: a pilot study
Authors: Begley Lesa , Madapoosi Siddharth , Opron Kristopher , Ndum Ogechukwu , Baptist Alan , Rysso Kelly , Erb-Downward John R , Huang Yvonne Jean
Published: September 2018

Introduction

Despite strong evidence that maturation patterns of the gut microbiome in early life influence the risk for childhood asthma, very little is known about gut microbiota patterns in adults with established asthma, and of greater interest relationships to phenotypic features that characterise asthma heterogeneity.

Methods

Fifty-eight faecal samples from 32 adults with (n=24) and without (n=8) asthma were analysed using 16S ribosomal RNA gene sequencing methods to characterise intestinal bacterial composition. Compositional stability of paired samples was evaluated and features of gut bacterial community structure analysed in relation to extensive clinical characterisation data collected from subjects, who were enrolled in a prospective observational cohort study at the University of Michigan.

Results

Differences in gut bacterial community structure were associated with aeroallergen sensitisation and lung function as assessed by forced expiratory volume in 1 s (FEV1) %predicted. Associations with FEV1were consistently observed across independent analytic approaches. k-means clustering of the gut microbiota data in subjects with asthma revealed three different clusters, distinguished most strongly by FEV1(p<0.05) and trends in differences in other clinical and inflammatory features.

Conclusion

In this pilot study of asthmatic and non-asthmatic subjects, significant relationships between gut microbiota composition, aeroallergen sensitisation and lung function were observed. These preliminary findings merit further study in larger cohorts to explore possible mechanistic links to asthma phenotype.
Chest wall mass: what lies beneath?
Authors: Richards Claire Elaine , Mostafa Ahmed Mamdouh Taha , Elmoheen Amr
Published: September 2018

Clinical introduction

A 24-year-old Filipino man attended the ED with a 1-month history of a discrete swelling over his upper anterior chest wall that was rapidly increasing in size and tenderness. He denied any other symptoms. His medical history was unremarkable.

Examination revealed a tender, 7 cm × 6 cm mass over the upper part of the sternum (figure 1). The surface was smooth, it was immobile, non-compressible and the overlying skin was normothermic but mildly erythematous. Cervical lymphadenopathy was present. His vital signs were normal.

Figure 1

Chest wall mass.

Question

What is the most likely diagnosis?

Lipoma

Chondrosarcoma

Lymphoma

Mycobacterium tuberculosis(TB)
BET 1: In paracetamol overdose, is oral N-acetylcysteine as effective as intravenous N-acetylcysteine?
Authors: Woodhead Kathryn , Foex Bernard A
Published: September 2018

A short-cut review was carried out to establish whether oral N-acetylcysteine is as effective as intravenous N-acetylcysteine in the management of paracetamol overdose. Seven studies were directly relevant to the question. The author, year and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. The clinical bottom line is that oral N-acetylcysteine is a safe alternative in patients for whom the intravenous route is not an option.
Outcome of transarterial treatment of dural arteriovenous fistulas with direct or indirect cortical venous drainage
Authors: Mantilla Daniel , Le Corre Marine , Cagnazzo Federico , Gascou Gregory , Eker Omer , Machi Paolo , Riquelme Carlos , Dargazanli Cyril , Costalat Vincent , Bonafe Alain , Lefevre Pierre-Henri
Published: September 2018

Background and purpose

Transarterial Onyx embolization is an effective treatment for patients with intracranial dural arteriovenous fistula (DAVF). A study was performed to determine whether the clinical and radiological outcomes after transarterial Onyx treatment were affected by the type of cortical venous drainage (direct vs indirect) of high-grade DAVF.

Materials and methods

Between May 2006 and December 2014, demographic data, clinical presentation, angiographic characteristics, and treatment-related outcomes were collected for 54 patients divided into two groups (intracranial DAVF with direct and indirect cortical venous drainage). Continuous variables were compared with the two-tailed t test and categorical variables with the χ2test. Statistical significance was set at P<0.05.

Results

Fifty-two patients (71% with direct and 29% with indirect cortical venous drainage) underwent Onyx embolization. Immediate complete occlusion after treatment was observed in about 55% of patients without between-group difference. During the long-term follow-up, complete angiographic occlusion was achieved in 83% of patients. Specifically, 15 additional patients (40%) in the direct cortical venous drainage group progressed to complete occlusion, but only one (6%) in the indirect cortical venous drainage group. Overall, the rate of complete occlusion was higher in patients with DAVF with direct cortical venous drainage (92%) than in those with DAVF with indirect cortical venous drainage (62.5%) (P=0.01). The rate of permanent treatment-related complications was 4%, mostly related to ischemic events. Overall, 80.5% of patients had a good neurological outcome (modified Rankin Scale score 0–2).

Conclusions

Transarterial Onyx embolization of intracranial high-grade DAVF is safe and effective, particularly for lesions with direct cortical venous drainage.