bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing Sociotechnical Complexity in Engineering Design Projects
Authors: Hassannezhad Mohammad , Cantamessa Marco , Montagna Francesca , Clarkson P. John
Published: February 2019

Design project management is witnessing an increasing need for practitioners to rely on tools that reflect the integrated nature of the social and technical characteristics of design processes, as opposed to considering the two as separate concepts. For practitioners, this integration has the potential value of predicting the future behavior of design processes by allowing them to understand what task to do next, whom to assign a task given the availability of resource, and the levels of knowledge and expertise required. In response to these challenges, this paper contributes to the development of a new process modeling method, called actor-based signposting (ABS), that looks at the early stages of the product development processes from the perspective of integrated sociotechnical systems. The objective is to support managers and decision-makers on both typical planning issues, such as scheduling and resource allocation, and less conventional issues relating to the organizational planning of a design project, such as identification of criticalities, matching required skills and expertise, and factors of influence. Ultimately, the aim is to support organizations to be more adaptive in responding to change and uncertainty. Two case studies in the automotive and aerospace industries with different properties and modeling objectives were selected to demonstrate the utility of the proposed method. Experimental analysis of these cases led to a range of insights regarding the future of modeling for academia as well as the decision-making capabilities for managers and practitioners.
Trajectory-Planning and Normalized-Variable Control for Parallel Pick-and-Place Robots
Authors: Karimi Eskandary Peyman , Belzile Bruno , Angeles Jorge
Published: February 2019

Trajectory planning and an efficient control scheme play a crucial role in improving the performance of pick-and-place robots. This paper introduces a novel method of trajectory planning with cycle time and path constraints. Assuming that a smooth trajectory is given, to be followed within a prescribed cycle time, the newly proposed method of trajectory planning removes the torque peaks of the actuators by a suitable scheduling of the velocity of the moving plate. Since pick-and-place robots are usually expected to meet the end poses in a certain time span, while disregarding the intermediate poses, the velocity can be tuned properly around the critical points of the trajectory by means of a time-scaling function. Moreover, the authors report the formulation of a linear quadratic regulator (LQR) controller with normalized variables to be used in conjunction with our trajectory-tracking control scheme for an in-house-developed Schönflies-motion generator. This parallel robot offers a functionally symmetric, single-loop architecture, with an isostatic kinematic chain, and virtually unlimited rotatability of its gripper. A comparison between two actuation systems developed by the authors is conducted via simulation results.
Heat Transfer in a Rotating Two-Pass Rectangular Channel Featuring Reduced Cross-Sectional Area After Tip Turn (Aspect Ratio = 4:1 to 2:1) With Profiled 60 deg Angled Ribs
Authors: Chen Andrew F , Shiau Chao-Cheng , Han Je-Chin , Krewinkel Robert
Published: February 2019

The present study features a two-pass rectangular channel with an aspect ratio (AR) = 4:1 in the first pass and an AR = 2:1 in the second pass after a 180-deg tip turn. In addition to the smooth-wall case, ribs with a profiled cross section are placed at 60 deg to the flow direction on both the leading and trailing surfaces in both passages (P/e = 10, e/Dh ∼ 0.11, parallel and in-line). Regionally averaged heat transfer measurement method was used to obtain the heat transfer coefficients on all internal surfaces. The Reynolds number (Re) ranges from 10,000 to 70,000 in the first passage, and the rotational speed ranges from 0 to 400 rpm. Under pressurized condition (570 kPa), the highest rotation number achieved was Ro = 0.39 in the first passage and 0.16 in the second passage. The results showed that the turn-induced secondary flows are reduced in an accelerating flow. The effects of rotation on heat transfer are generally weakened in the ribbed case than the smooth case. Significant heat transfer reduction (∼30%) on the tip wall was seen in both the smooth and ribbed cases under rotating condition. Overall pressure penalty was reduced for the ribbed case under rotation. Reynolds number effect was found noticeable in the current study. The heat transfer and pressure drop characteristics are sensitive to the geometrical design of the channel and should be taken into account in the design process.
Study on Coupling Fault Dynamics of Sliding Bearing-Rotor System
Authors: Liu Yang , Xin Xicheng , Zhao Yulai , Ming Shuaishuai , Ma Yaxin , Han Jiyuan
Published: February 2019

The phenomenon of oil film oscillation and frequency locked may occur in a healthy rotor system which is supported by sliding bearing. The dynamic behavior of the rotor system with misalignment and rubbing coupling fault supported by sliding bearing is also very complex. To solve the problem of fault diagnosis in this case, a dynamical model of rotor system is proposed in this paper. The short bearing oil film force, the equivalent misalignment moment, and Hertz contact theory are applied to establish the model. For rubbing faults, the Augmented Lagrange method is used to deal with the contact constraints to ensure that the boundary penetration depth is within the specified tolerance range. Furthermore, the dynamic behavior of the faulty rotor system under different rubbing stiffness conditions is analyzed in this paper. Meanwhile, the fault signal is divided into equal-band by the wavelet basis functions to find out the fault frequency band of the rotor system. Finally, the accuracy of the simulation study is verified by measurements obtained from the faulty rotor test platform. The following findings are made in this paper. The rubbing fault is dominant in the coupling fault. With the increasing of the speed, the frequency components of the system are dominated by high frequency. The double frequency is the main fault feature frequency band. It can be seen that the rotor system moves gradually from a quasi-periodic state into chaos due to the Lyapunov exponent. At the same time, due to the effects of misalignment moment and friction force, the phenomenon of oil film instability is partially suppressed. The lagging of the first and second-order oil film oscillations occurs.
Model-Form and Parameter Uncertainty Quantification in Structural Vibration Simulation Using Fractional Derivatives
Authors: Zhang Baoqiang , Guo Qintao , Wang Yan , Zhan Ming
Published: February 2019

Extensive research has been devoted to engineering analysis in the presence of only parameter uncertainty. However, in modeling process, model-form uncertainty arises inevitably due to the lack of information and knowledge, as well as assumptions and simplifications made in the models. It is undoubted that model-form uncertainty cannot be ignored. To better quantify model-form uncertainty in vibration systems with multiple degrees-of-freedom, in this paper, fractional derivatives as model-form hyperparameters are introduced. A new general model calibration approach is proposed to separate and reduce model-form and parameter uncertainty based on multiple fractional frequency response functions (FFRFs). The new calibration method is verified through a simulated system with two degrees-of-freedom. The studies demonstrate that the new model-form and parameter uncertainty quantification method is robust.
An Adaptive Multiscaling Approach for Reducing Computation Time in Simulations of Articulated Biopolymers
Authors: Guy Ashley , Bowling Alan
Published: February 2019

Microscale dynamic simulations can require significant computational resources to generate desired time evolutions. Microscale phenomena are often driven by even smaller scale dynamics, requiring multiscale system definitions to combine these effects. At the smallest scale, large active forces lead to large resultant accelerations, requiring small integration time steps to fully capture the motion and dictating the integration time for the entire model. Multiscale modeling techniques aim to reduce this computational cost, often by separating the system into subsystems or coarse graining to simplify calculations. A multiscale method has been previously shown to greatly reduce the time required to simulate systems in the continuum regime while generating equivalent time histories. This method identifies a portion of the active and dissipative forces that cancel and contribute little to the overall motion. The forces are then scaled to eliminate these noncontributing portions. This work extends that method to include an adaptive scaling method for forces that have large changes in magnitude across the time history. Results show that the adaptive formulation generates time histories similar to those of the unscaled truth model. Computation time reduction is consistent with the existing method.
Chaotic and Hyperchaotic Dynamics of a Modified Murali–Lakshmanan–Chua Circuit
Authors: Manimehan I. , Paul Asir M. , Philominathan P.
Published: February 2019

The present study uncovers the hyperchaotic dynamical behavior of the famous Murali-Lakshmanan-Chua (MLC) circuit, when suitably modified. In the conventional MLC oscillator, an inductor is introduced in parallel between the nonlinear element and the capacitor. Many novel and interesting dynamical behaviors such as reverse period-3 doubling, torus breakdown to chaos and hyperchaos, etc., were observed. Characterization techniques includes spectrum of Lyapunov exponents, one parameter bifurcation diagram, recurrence quantification analysis, correlation dimension, etc., were employed to analyze the different dynamical regimes. Explicit analytical solution of the model is derived and the results are corroborated with the numerical outcomes.
On the Application of the Multiple Scales Method on Electrostatically Actuated Resonators
Authors: Ilyas Saad , Alfosail Feras K. , Younis Mohammad I.
Published: February 2019

We investigate modeling the dynamics of an electrostatically actuated resonator using the perturbation method of multiple time scales (MTS). First, we discuss two approaches to treat the nonlinear parallel-plate electrostatic force in the equation of motion and their impact on the application of MTS: expanding the force in Taylor series and multiplying both sides of the equation with the denominator of the forcing term. Considering a spring–mass–damper system excited electrostatically near primary resonance, it is concluded that, with consistent truncation of higher-order terms, both techniques yield same modulation equations. Then, we consider the problem of an electrostatically actuated resonator under simultaneous superharmonic and primary resonance excitation and derive a comprehensive analytical solution using MTS. The results of the analytical solution are compared against the numerical results obtained by long-time integration of the equation of motion. It is demonstrated that along with the direct excitation components at the excitation frequency and twice of that, higher-order parametric terms should also be included. Finally, the contributions of primary and superharmonic resonance toward the overall response of the resonator are examined.
A Lead Garment Structural Systemto Reduce Musculoskeletal Stress During Fluoroscopy
Authors: Johnson Hilary A. , Miller Sally , Cervantes Thomas M. , Teo Tat Joo , Mehta Nishaki , Slocum Alexander H.
Published: February 2019

Cardiovascular, orthopedic, and interventional radiology procedures using fluoroscopy require healthcare professionals to wear heavy lead garments for radiation protection, which can lead to musculoskeletal injuries, discomfort, and fatigue. A mobile lead garment frame, MobiLead, was designed to mitigate these issues by moving the lower garment load off body to a structural frame and redistributing the load of the upper garment from the shoulders to the hips through a torso frame. The frame was designed to be compact with a minimal footprint for maneuverability in operating rooms with limited space, while still giving the surgeon adequate mobility for various emergency procedures. Preliminary analysis of device efficacy was conducted using electromyography (EMG) of load-bearing muscles during use and qualitative surgeon user feedback surveys. Nonparametric permutation tests showed that the MobiLead device mean activation was significantly lower than the standard lead garment (p<0.001). Surgeon feedback and use testing showed that the device fits under a sterile gown and is maneuverable in an operating room (OR).
Safety Constraints of Instrumental and Control Algorithm Configuration Based on SCADE Platform
Authors: Liu Hua , Yang Xiao-Hua , Liu Zhao-Hui , Yan Shi-Yu , Li Meng , Liu Jie , Chen Zhi
Published: February 2019

Algorithm library plays an important role in digital instrument control system. In the design process, software testing and safety verification are focused on safety and reliability of the algorithm library. The configured parameters are important for the safety and reliability. Relations of parameters among different modules are very complex. Parameters are easy to be wrongly configured in the design process. Parameters must be considered and checked. The analysis process of safety constraints is established. The analysis is not only important for the sufficient in the design validation and verification but also improves design quality and decreasing the defects.
Numerical Analysis of Mechanical Behavior of Buried Pipes in Subsidence Area Caused by Underground Mining
Authors: Zhang Jie , Xie Rui
Published: February 2019

The buried pipe crossing the subsidence area is prone to failure. The mechanical behavior of buried pipe in subsidence area was investigated in this paper. Effects of subsidence displacement, pipe parameters and soil parameters on the mechanical behavior were investigated. The results show that high stress appears on the pipe's surface and exceeds the yield strength after the strata subsidence. As subsidence displacement increases, the ranges of high-stress area and displacement increase, and the pipe section changes from a circle to an ellipse. The maximum axial strain occurs on the pipe in no-subsidence area. The maximum plastic strain and ovality of the pipe increase with the increasing of subsidence displacement. The displacement, plastic strain, and ovality of the pipe increase with the increasing of diameter–thickness ratio and buried depth. Internal pressure and friction coefficient has a little effect on the pipe displacement. The ovality decreases as internal pressure increases. The plastic strain and ovality increase with the increasing of the friction coefficient. As the elastic modulus and cohesion of soil increase, the displacement, plastic strain, and ovality of the pipe increase. The effect of Poisson's ratio on the deformation of pipe is small.
Mathematical Modeling of Fluid Flow to Unconventional Oil Wells With Radial Fractures and Its Testing With Field Data
Authors: Hou Xuejun , Zhang Xiaohui , Guo Boyun
Published: February 2019

Radial fractures are created in unconventional gas and oil reservoirs in modern well stimulation operations such as hydraulic refracturing (HRF), explosive fracturing (EF), and high energy gas fracturing (HEGF). This paper presents a mathematical model to describe fluid flow from reservoir through radial fractures to wellbore. The model can be applied to analyzing angles between radial fractures. Field case studies were carried out with the model using pressure transient data from three typical HRF wells in a lower-permeability reservoir. The studies show a good correlation between observed well performance and model-interpreted fracture angle. The well with the highest productivity improvement by the HRF corresponds to the interpreted perpendicular fractures, while the well with the lowest productivity improvement corresponds to the interpreted conditions where the second fracture is much shorter than the first one or where there created two merged/parallel fractures. Result of the case studies of a tight sand reservoir supports the analytical model.
Performances and Emissions Evaluation of a Microturbojet Engine Running on Biodiesel Blends
Authors: Cican Grigore , Plesu Valentin , Deaconu Marius , Toma Adina , Cretu Mihaiella
Published: February 2019

This paper analyzes the performances and the emissions of the JETCAT P80 microengine, when jet A jet A +  10% biodiesel (BD), jet A + 20% biodiesel, and jet A + 30% biodiesel are utilized as fuel, and to each of these combinations is added 5% of Aeroshell Oil 500. The performances will be assessed based on the engine speed, for the generated thrust force, the temperature in front of the turbine, and on the fuel flow. The paper will investigate the performances and the emissions generated by the four fuel blends burning when the engine is idle, at the cruise and at the max regime. This will be realized by maintaining each of these regimes for approximately a minute and a half. During the tests, the vibrations were monitored both radially and axially for the observation of the engine function regimes. From the measurements, the concentrations of SO2, NOx, and CH4 will be analyzed, highlighting the emissions of SO2. There were performed measurements to determine the fuel blend's density in order to transform the values of the fuel flow from liter per hour into kilogram per second. Having these data registered from the engine, a jet engine cycle analysis at max regime will be performed based on the combustion efficiency, the thermal efficiency of the engine, and the specific fuel consumption.
Measurements Versus Predictions for a Hybrid (Hydrostatic Plus Hydrodynamic) Thrust Bearing for a Range of Orifice Diameters
Authors: Childs Dara W. , Esser Paul
Published: February 2019

A fixed-geometry hybrid thrust bearing is investigated with three different supply orifice diameters, (1.63, 1.80, and 1.93 mm). The test rig uses a face-to-face thrust-bearing design, with the test bearing acting as the rotor loading mechanism. A hydraulic shaker applies the static axial load, which is reacted by a second (slave) thrust bearing. The rotor is supported radially by two water-lubricated fluid-film journal bearings and is attached to a 30.6 krpm motor via a high-speed coupling with very low axial stiffness. Thrust bearings are tested for a range of supply pressures (5.17, 10.34, and 17.34 bars), fluid film thicknesses, and speeds (7.5, 12.5, and 17.5 krpm). The water-lubricated test bearings have eight pockets, with feed orifices located centrally in each pocket. Experimental results are compared to predictions from a bulk-flow model, showing generally good agreement. Thrust-bearing inlet supply and inner radius flow rates all decreased with decreasing orifice diameters and bearing axial clearances. In most cases, the bearings with larger orifice diameters exhibit higher recess pressure ratios, operating clearances, and flow rates. An optimum hybrid thrust-bearing orifice diameter will depend on the conditions of individual applications. Larger orifices generally provide larger operating clearances and higher stiffnesses, but also require higher flow rates. For most applications, a compromise of bearing performance parameters will be desired. The test results and comparisons presented will aid in sizing orifice diameters for future hybrid thrust-bearing designs and in validating and improving models and predictions.
Performance Evaluation of Combined Photovoltaic Thermal Water Cooling System for Hot Climate Regions
Authors: Salem Ahmed M. , Mohamed A. S. A. , Maghrabie Hussein M.
Published: February 2019

Solar electric power generation utilizing photovoltaic (PV) modules is associated with low electrical efficiency that substantially decreases as its surface temperature exceeds an appropriate limit, particularly in hot climate regions. Consequently, it is required to keep PV modules relatively under a condition of low temperature using a cooling system as possible. The present experimental study evaluates the performance of the combined photovoltaic thermal (PV/T) module employing a water cooling system attached to the back surface during June for the city of Sohag in Egypt. The experimental results show that utilizing a water cooling system decreases the average surface temperature of the PV module from 44.8 °C to 30.3 °C on the back side and from 46.6 °C to 36.9 °C on the front side. The maximum value of the thermal heat gain of the PV/T module that is maintained at noon equals 230 W, and the corresponding value of the electrical power output is 34.4 W. Furthermore, the electrical efficiency of the PV/T module is 8% higher than that of the PV module without a water cooling system. Finally, the maximum and average values of the overall efficiency of PV/T module are 76.4% and 68.9%, respectively.
Detection of Candidatus Rickettsia tarasevichiae from tick collected from human patient, South Korea
Authors: Jang Won-Jong , Lee Mi-Kyung , Kim Heung-Chul , Choi Yeon-Joo , Kim Jeoungyeon , Park Hye-Jin , Song Dayoung , Park Kyung-Hee
Published: February 2019

Here we report the detection of Candidatus Rickettsia tarasevichiae from tick collected from human patient through DNA amplification. The tick was identified to be Haemaphysalis longicornis. We amplified and sequenced rickettsial citrate synthase gene (gltA), 190_kDa outer protein gene (ompA), and 120_ kDa outer protein gene (ompB). Sequencing results showed that gltA gene and ompA (GenBank accession No. KT899085, KT899079, respectively) shared 100% nucleotide sequence similarities with Candidatus R. tarasevichiae. In addition, ompB gene shared 96% nucleotide sequence similarity with R. canadensis. However, DNA extracted from patient serum showed 98% sequence similarity with R. japonica (AF123713.1). This result implies that H. longicornis ticks harbor both Candidatus R. tarasevichiae and R. japonica.
Singing together: Pitch accuracy and interaction in unaccompanied unison and duet singing
Authors: Dai Jiajie , Dixon Simon
Published: February 2019

This paper investigates singing interaction by analysis of the factors influencing pitch accuracy of unaccompanied pairs of singers. Eight pairs of singers sang two excerpts either in unison or two-part harmony. The experimental condition varied which singers could hear singing partners. After semi-automatic pitch-tracking and manual checking, this paper calculated the pitch error (PE) and interval error and tested the factors of influence using a one-way analysis of variance and a linear mixed-effects model. The results indicate that: (1) singing with the same vocal part is more accurate than singing with a different vocal part; (2) singing solo has less pPE than singing with a partner; (3) PEs are correlated, as singers adjust pitch to mitigate a partner's error and preserve harmonic intervals at the expense of melodic intervals and absolute pitch; (4) other factors influence the pitch accuracy, including: score pitch, score harmonic interval, score melodic interval, musical background, vocal part, and individual differences.
Temporal dynamics and uncertainty in binaural hearing revealed by anticipatory eye movements
Authors: Winn Matthew B. , Kan Alan , Litovsky Ruth Y.
Published: February 2019

Accurate perception of binaural cues is essential for left-right sound localization. Much literature focuses on threshold measures of perceptual acuity and accuracy. This study focused on supra-threshold perception using an anticipatory eye movement (AEM) paradigm designed to capture subtle aspects of perception that might not emerge in behavioral-motor responses, such as the accumulation of certainty, and rapid revisions in decision-making. Participants heard interaural timing differences (ITDs) or interaural level differences in correlated or uncorrelated narrowband noises, respectively. A cartoon ball moved behind an occluder and then emerged from the left or right side, consistent with the binaural cue. Participants anticipated the correct answer (before it appeared) by looking where the ball would emerge. Results showed quicker and more steadfast gaze fixations for stimuli with larger cue magnitudes. More difficult stimuli elicited a wider distribution of saccade times and greater number of corrective saccades before final judgment, implying perceptual uncertainty or competition. Cue levels above threshold elicited some wrong-way saccades that were quickly corrected. Saccades to ITDs were earlier and more reliable for low-frequency noises. The AEM paradigm reveals the time course of uncertainty and changes in perceptual decision-making for supra-threshold binaural stimuli even when behavioral responses are consistently correct.
Interspecies Chemical Signaling in a Methane-Oxidizing Bacterial Community
Authors: Puri Aaron W. , Liu Darren , Schaefer Amy L. , Yu Zheng , Pesesky Mitchell W. , Greenberg E. Peter , Lidstrom Mary E.
Published: February 2019

Methanotrophs are bacteria that sequester methane, a significant greenhouse gas, and thereby perform an important ecosystem function. Understanding the mechanisms by which these organisms interact in the environment may ultimately allow us to manipulate and to optimize this activity. Here we show that members of a genus of methane-oxidizing bacteria can be influenced by a chemical signal produced by a possibly competing species. This provides insight into how gene expression can be controlled in these bacterial communities via an exogenous chemical signal.
Dissecting the Evolutionary Development of the Species
Bifidobacterium animalis
through Comparative Genomics Analyses
Authors: Lugli Gabriele Andrea , Mancino Walter , Milani Christian , Duranti Sabrina , Mancabelli Leonardo , Napoli Stefania , Mangifesta Marta , Viappiani Alice , Anzalone Rosaria , Longhi Giulia , van Sinderen Douwe , Ventura Marco , Turroni Francesca
Published: February 2019

The majority of characterized
B. animalis
strains have been isolated from human fecal samples. In order to explore genome variability within this species, we isolated 15 novel strains from the gastrointestinal tracts of different animals, including mammals and birds. The present study allowed us to reconstruct the pangenome of this taxon, including the genome contents of 56
B. animalis
strains. Through careful assessment of subspecies-specific core genes of the
B. animalis
subsp.
animalis
/
lactis
taxon, we identified genes encoding enzymes involved in carbohydrate transport and metabolism, while unveiling specific gene acquisition and loss events that caused the evolutionary emergence of these two subspecies.
Role of RpoN from
Labrenzia aggregata
LZB033 (
Rhodobacteraceae
) in Formation of Flagella and Biofilms, Motility, and Environmental Adaptation
Authors: Xu Tingting , Yu Min , Liu Jingli , Lin Heyu , Liang Jinchang , Zhang Xiao-Hua
Published: February 2019

This study established an in-frame gene deletion method in the alphaproteobacterium
Labrenzia aggregata
LZB033 and generated an
rpoN
gene mutant. A comparison of the transcriptomes and phenotypic characteristics between the mutant and wild-type strains confirmed the role of RpoN in
L. aggregata
LZB033 flagellar formation, motility, biofilm formation, and carbon usage. Most importantly, RpoN is a key factor for survival under different environmental challenge conditions. Furthermore, the ability to synthesize and metabolize dimethylsulfoniopropionate (DMSP) was related to RpoN. These features revealed RpoN to be an important regulator of stress resistance and survival for
L. aggregata
LZB033 in marine environments.
Functional Reorganization of Promyelocytic Leukemia Nuclear Bodies during BK Virus Infection
Authors: Jiang Mengxi , Entezami Pouya , Gamez Monica , Stamminger Thomas , Imperiale Michael J.
Published: February 2019

BK virus (BKV) is the causative agent for polyomavirus-associated nephropathy, a severe disease found in renal transplant patients due to reactivation of a persistent BKV infection. BKV replication relies on the interactions of BKV with many nuclear components, and subnuclear structures such as promyelocytic leukemia nuclear bodies (PML-NBs) are known to play regulatory roles during a number of DNA virus infections. In this study, we investigated the relationship between PML-NBs and BKV during infection of primary human renal proximal tubule epithelial (RPTE) cells. While the levels of the major PML-NB protein components remained unchanged, BKV infection of RPTE cells resulted in dramatic alterations in both the number and the size of PML-NBs. Furthermore, two normally constitutive components of PML-NBs, Sp100 and hDaxx, became dispersed from PML-NBs. To define the viral factors responsible for this reorganization, we examined the cellular localization of the BKV large tumor antigen (TAg) and viral DNA. TAg colocalized with PML-NBs during early infection, while a number of BKV chromosomes were adjacent to PML-NBs during late infection. We demonstrated that TAg alone was not sufficient to reorganize PML-NBs and that active viral DNA replication is required. Knockdown of PML protein did not dramatically affect BKV growth in culture. BKV infection, however, was able to rescue the growth of an ICP0-null herpes simplex virus 1 mutant whose growth defect was partially due to its inability to disrupt PML-NBs. We hypothesize that the antiviral functions of PML-NBs are inactivated through reorganization during normal BKV infection.

IMPORTANCE
BK virus (BKV) is a human pathogen that causes severe diseases, including polyomavirus-associated nephropathy in kidney transplant patients and hemorrhagic cystitis in bone marrow transplant recipients. How BKV replication is regulated and the effects of a lytic BKV infection on host cells at the molecular level are not well understood. Currently, there is no specific antiviral treatment for BKV-associated disease, and a better understanding of the complete life cycle of the virus is necessary. Here, we report the interplay between BKV and one of the regulatory structures in the host cell nucleus, promyelocytic leukemia nuclear bodies (PML-NBs). Our results show that BKV infection reorganizes PML-NBs as a strategy to inactivate the negative functions of PML-NBs.
Identification of Novel
Acinetobacter baumannii
Host Fatty Acid Stress Adaptation Strategies
Authors: Jiang Jhih-Hang , Hassan Karl A. , Begg Stephanie L. , Rupasinghe Thusitha W. T. , Naidu Varsha , Pederick Victoria G. , Khorvash Marjan , Whittall Jonathan J. , Paton James C. , Paulsen Ian T. , McDevitt Christopher A. , Peleg Anton Y. , Eijkelkamp Bart A.
Published: February 2019

A shift in the Western diet since the industrial revolution has resulted in a dramatic increase in the consumption of omega-6 fatty acids, with a concurrent decrease in the consumption of omega-3 fatty acids. This decrease in omega-3 fatty acid consumption has been associated with significant disease burden, including increased susceptibility to infectious diseases. Here we provide evidence that DHA, an omega-3 fatty acid, has superior antimicrobial effects upon the highly drug-resistant pathogen
Acinetobacter baumannii
, thereby providing insights into one of the potential health benefits of omega-3 fatty acids. The identification and characterization of two novel bacterial membrane protective mechanisms against host fatty acids provide important insights into
A. baumannii
adaptation during disease. Furthermore, we describe a novel role for the major multidrug efflux system AdeIJK in
A. baumannii
membrane maintenance and lipid transport. This core function, beyond drug efflux, increases the appeal of AdeIJK as a therapeutic target.
Dopamine Is a Siderophore-Like Iron Chelator That Promotes
Salmonella enterica
Serovar Typhimurium Virulence in Mice
Authors: Dichtl Stefanie , Demetz Egon , Haschka David , Tymoszuk Piotr , Petzer Verena , Nairz Manfred , Seifert Markus , Hoffmann Alexander , Brigo Natascha , Würzner Reinhard , Theurl Igor , Karlinsey Joyce E. , Fang Ferric C. , Weiss Günter
Published: February 2019

Here we show that dopamine increases bacterial iron incorporation and promotes
Salmonella
Typhimurium growth both
in vitro
and
in vivo
. These observations suggest the potential hazards of pharmacological catecholamine administration in patients with bacterial sepsis but also suggest that the inhibition of bacterial iron acquisition might provide a useful approach to antimicrobial therapy.
Didehydro-Cortistatin A Inhibits HIV-1 by Specifically Binding to the Unstructured Basic Region of Tat
Authors: Mediouni Sonia , Chinthalapudi Krishna , Ekka Mary K. , Usui Ippei , Jablonski Joseph A. , Clementz Mark A. , Mousseau Guillaume , Nowak Jason , Macherla Venkat R. , Beverage Jacob N. , Esquenazi Eduardo , Baran Phil , de Vera Ian Mitchelle S. , Kojetin Douglas , Loret Erwann P. , Nettles Kendall , Maiti Souvik , Izard Tina , Valente Susana T.
Published: February 2019

Tat activates virus production, and limited Tat transactivation correlates with HIV-1 latency. The Tat inhibitor dCA locks HIV in persistent latency. This drug class enables block-and-lock functional cure approaches, aimed at reducing residual viremia during therapy and limiting viral rebound. dCA may also have additional therapeutic benefits since Tat is also neurotoxic. Unfortunately, Tat inhibitors are not clinically available. We generated chemical derivatives and rationalized binding to an active and specific Tat conformer. dCA features required for Tat inhibition are distinct from features needed for inhibition of cyclin-dependent kinase 8 (CDK8), the only other known target of dCA. Furthermore, knockdown of CDK8 did not impact dCA’s activity on HIV-1 transcription. Binding of dCA to Tat’s basic domain altered the local protein environment and rendered Tat more resistant to proteolytic digestion. dCA locks a transient conformer of Tat, blocking functions dependent on its basic domain, namely its ability to amplify viral transcription. Our results define dCA’s mode of action, support structure-based-design strategies targeting Tat, and provide valuable information for drug development around the dCA pharmacophore.
Mucor circinelloides
Thrives inside the Phagosome through an Atf-Mediated Germination Pathway
Authors: Pérez-Arques Carlos , Navarro-Mendoza María Isabel , Murcia Laura , Lax Carlos , Martínez-García Pablo , Heitman Joseph , Nicolás Francisco E. , Garre Victoriano
Published: February 2019

Mucorales are a group of ancient saprophytic fungi that cause neglected infectious diseases collectively known as mucormycoses. The molecular processes underlying the establishment and progression of this disease are largely unknown. Our work presents a transcriptomic study to unveil the
Mucor circinelloides
genetic network triggered in fungal spores in response to phagocytosis by macrophages and the transcriptional response of the host cells. Functional characterization of differentially expressed fungal genes revealed three transcription factors and three extracellular proteins essential for the fungus to survive and germinate inside the phagosome and to cause disease in mice. Two of the transcription factors, highly similar to activating transcription factors (ATFs), coordinate a complex secondary gene response involved in pathogenesis. The significance of our research is in characterizing the initial stages that lead to evasion of the host innate immune response and, in consequence, the dissemination of the infection. This genetic study offers possible targets for novel antifungal drugs against these opportunistic human pathogens.
BldC Delays Entry into Development To Produce a Sustained Period of Vegetative Growth in Streptomyces venezuelae
Authors: Bush Matthew J. , Chandra Govind , Al-Bassam Mahmoud M. , Findlay Kim C. , Buttner Mark J.
Published: February 2019

Understanding the mechanisms that drive bacterial morphogenesis depends on the dissection of the regulatory networks that underpin the cell biological processes involved. Recently,
Streptomyces venezuelae
has emerged as an attractive model system for the study of morphological differentiation in
Streptomyces
. This has led to significant progress in identifying the genes controlled by the transcription factors that regulate aerial mycelium formation (Bld regulators) and sporulation (Whi regulators). Taking advantage of
S. venezuelae
, we used ChIP-seq coupled with RNA-seq to identify the genes directly under the control of BldC. Because
S. venezuelae
sporulates in liquid culture, the complete spore-to-spore life cycle can be examined using time-lapse microscopy, and we applied this technique to the
bldC
mutant. These combined approaches reveal BldC to be a member of an emerging class of Bld regulators that function principally to repress key sporulation genes, thereby extending vegetative growth and blocking the onset of morphological differentiation.
Maculopathy from an accidental exposure to welding arc
Authors: Kim Min-Seok , Lee Sang-Gil , Kim Jae Yun , Kang Mo-Yeol
Published: February 2019

Welding light can cause photic retinal injury. We report binocular maculopathy induced by a brief exposure to electric arc welding light in a patient who could not equipped with protective device because of narrow space. A 47-year-old man performed electric arc welding for approximately 10–15 min without wearing protective device because of narrow space and subsequently experienced eye discomfort and decreased visual acuity. At the initial visit, his best corrected visual acuity was 0.5. Fundus examination, optical coherence tomography (OCT) and multifocal electroretinogram (mfERG) were performed. OCT showed disruption in the ellipsoid zone, and mfERG amplitudes in the central 10° were markedly reduced in both eyes. The decrease in visual acuity had been noted for at least 18 months. Using the proper protective device is essential in welding, despite short time periods of work. For patients with welding-induced photokeratitis, doctors should also consider the possibility of photic retinal injury.
Impact of patient-centred and family-centred care meetings on intensive care and resource utilisation in patients with terminal illness: a single-centre retrospective observational study in Taiwan
Authors: Hsu Nin-Chieh , Huang Chun-Che , Chen Wei-Chun , Yu Chong-Jen
Published: February 2019

Objective

Shared decision making is essential for patients and their families when facing serious and life-threatening diseases. This study aimed to evaluate the impact of patient-centred and family-centred care meetings (PFCCM) on intensive measures and resource utilisation during end-of-life (EOL) hospitalisation among terminally ill patients.

Design and setting

A retrospective cross-sectional study using electronic medical records was conducted in a tertiary referral medical centre in Taiwan.

Participants

We identified 6843 deceased patients with terminal illness who either received or did not receive PFCCM during EOL hospitalisation between January 2013 and December 2015.

Primary and secondary outcome measures

Patients who were transferred to the intensive care unit (ICU). Those who underwent invasive or non-invasive mechanical ventilation, tracheostomy, haemodialysis and surgical intervention during the final hospitalisation were determined by the use of intensive care measures; secondary measures were individual total and daily medical expenditures. A generalised estimating equation (GEE) model was used to compare the differences between the two groups. OR and beta coefficients (β) with 95% CI were estimated.

Results

This study identified 459 patients (6.7%) who received PFCCM during EOL hospitalisation. Multivariate analyses showed that patients who received PFCCM were less likely to have ICU admissions (OR 0.44, 95% CI 0.34 to 0.57), undergo surgical interventions (OR 0.74, 95% CI 0.58 to 0.95) and invasive mechanical ventilation (OR 0.50, 95% CI 0.38 to 0.66) during the final hospitalisation, after adjusting for patient demographics, clinical conditions and year of admission. Additionally, a significant decrease in daily medical expenditures was observed in PFCCM patients (β −0.18, 95% CI −0.25 to −0.12) than in non-PFCCM patients.

Conclusions

Patient–physician discussion through PFCCM is associated with less intensive care utilisation and daily medical expenditure during EOL hospitalisation in terminally ill patients.
Differences in burnout prevalence between clinical professionals and biomedical scientists in an academic medical centre: a cross-sectional survey
Authors: Messias Erick , Gathright Molly M , Freeman Emily S , Flynn Victoria , Atkinson Timothy , Thrush Carol R , Clardy James A , Thapa Purushottam
Published: February 2019

Objective

To determine the prevalence and associated factors for personal, work-related and patient/client-related burnout in clinical professionals and biomedical scientists in academic medicine.

Design

Prevalence survey using the Copenhagen Burnout Inventory.

Setting

Mid-size academic health centre.

Participants

Clinical providers (n=6489) and biomedical scientists (n=248) were invited to complete the survey. 1646 completed responses (response rate 24.4%) were analysed.

Primary and Secondary outcome measures

Prevalence estimates and adjusted ORs (AOR) were stratified for gender, age and professional category.

Results

Type of burnout varies across professional categories, with significant differences between clinicians and scientists. The prevalence of personal burnout was 52.7% (95%CI 50% to 55%), work-related burnout 47.5% (95%CI 45% to 49%) and patient/client-related burnout 20.3% (95%CI 18% to 22%). The prevalence of personal and work-related burnout was higher among women, while those aged 20–30 had a higher prevalence of all three burnout categories. Overall, clinical professionals had higher personal and work-related burnout, while biomedical scientists had higher client-related burnout. Accounting for the effects of gender and age, a significantly higher risk for personal burnout was found for physicians (AOR 1.64; 95%CI 1.3 to 2.1) and nurses (AOR 1.5; 95%CI 1.03 to 2.2). Significantly higher odds of work-related burnout were found for nurses (AOR 1.5; 95%CI 1.2 to 1.9) and residents (AOR 1.9; 95%CI 1.04 to 3.6). Basic scientists (AOR 10.0; 95%CI 5.7 to 17.6), physicians (AOR 2.8; 95%CI 1.9 to 4.1) and nurses (AOR 2.1; 95%CI 1.3 to 3.5) had higher odds of patient/client-related burnout.

Conclusions

Types of burnout are unevenly distributed in academic medical centres. Physicians have higher risk of personal and patient/client-related burnout, residents have higher risk of work-related burnout, basic scientists are at higher risk of client-related burnout and nurses have higher odds of all three types of burnout. Interventions addressing the problem of burnout in clinical environments may be inadequate to support biomedical scientists.
Application of a novel sex independent anthropometric index, termed angle index, in relation to type 2 diabetes: a Trinidadian case–control study
Authors: Ramnanansingh Terry Gavaskar , Nayak Shivananda Bijoor
Published: February 2019

Objective

To develop a novel sex independent anthropometric index, termed as angle index, related to type 2 diabetes.

Design

Case–control.

Participants

The study comprised 121 participants and were divided into two groups. One group had no form of diabetes and served as controls (n=50). The other group had the condition of type 2 diabetes (n=71). 31% (n=37) of the subjects were male and 69% (n=84) were female. 62% (n=75) of the subjects were of East Indian ethnicity, 28% (n=34) were of African ethnicity and 10% (n=12) were of mixed ethnicity.

Setting

Participants of the study were from the island of Trinidad, located in the Caribbean. Patients in the study were selected at random from hospital records.

Primary outcome measure

It was hypothesised that the mean angle index of patients with type 2 diabetes would be higher than the mean angle index of patients without type 2 diabetes.

Results

Patients with type 2 diabetes had a significantly higher angle index value as compared with controls (p<0.001). Angle index was the superior sex independent anthropometric index in relation to type 2 diabetes (area under the curve=0.72; p<0.001) as compared with other sex independent variables. Angle index correlated with glycated haemoglobin (rs=0.28, p=0.003) and fasting blood glucose (rs=0.31, p=0.001) levels. Patients with type 2 diabetes were four times more likely to have an angle index greater than 184° (OR 4.2, 95% CI 1.8 to 9.9) as compared with controls.

Conclusion

Angle index was a superior sex independent index for discriminating between patients with and without type 2 diabetes, as compared with waist circumference, abdominal volume index, conicity index, blood pressure readings, triglyceride levels and very low-density lipoprotein levels.
Why are male Chinese smokers unwilling to quit? A multicentre cross-sectional study on smoking rationalisation and intention to quit
Authors: Huang Xinyuan , Fu Wenjie , Zhang Haiying , Li Hong , Li Xiaoxia , Yang Yong , Wang Fan , Gao Junling , Zheng Pinpin , Fu Hua , Chapman Simon , Ding Ding
Published: February 2019

Objective

We aimed to describe the rationalisation beliefs endorsed by Chinese male smokers and to examine the association between rationalisation and the intention to quit.

Setting

Questionnaires were conducted among male smokers in three cities (Shanghai, Nanning and Mudanjiang) which represent different geographical locations, economic development levels and legislative status of tobacco control in China.

Design and participants

It was a multicentre cross-sectional survey involved a total of 3710 male smokers over 18 years.

Outcome measures

Primary outcomes were intention to quit, smoking rationalisation scores and sub scores in six dimensions. Smoking rationalisation was assessed using a newly developed Chinese rationalisation scale. Multivariable logistic regression was performed to examine the relationship between rationalisation and intention to quit.

Results

On average, smokers scored 3.3 out of 5 on the smoking rationalisation scale. With a one point increase in total rationalisation scale, the odds for intention to quit in the next 6 months decreased by 48% (OR=0.52, 95% CI: 0.44 to 0.61; p<0.001). Separate logistic regressions for six subscales of rationalisation shown consistent inverse associations with intention to quit (all p values <0.001). Believing that smoking was socially acceptable was the strongest predictor (OR=0.62, 95% CI: 0.55 to 0.71; p<0.001).

Conclusions

Rationalisation beliefs could be important barriers to smoking cessation. Some beliefs have stronger association with quit intention than others. Eroding rationalisation beliefs endorsed by smokers is a potential strategy for smoking cessation intervention.