bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Computer Simulation to Validate and Optimize the Design of an Innovative Electronic Packaging Concept
Authors: Beyerlein Dagmar , Hornberger Lee
Published: December 2020

Reducing integrated circuit (IC) plastic packaging production costs by improving the transfer mold and leadframe designs is a costly and time-consuming process. Rather than building mold and leadframe prototypes to perform empirical studies, this research describes how C-MOLD, a microchip encapsulation simulation software application, was used to validate and optimize an innovative mold and leadframe design that has the potential to reduce raw material waste associated with packaging by more than 59%. Estimates indicate that the proposed design will cut annual production costs by more than $600,000.
Continuous Temporal and Spatial Finite Element Boundary Condition Assignments Using a Neural Network Prediction System
Authors: Zhang Yong , Sullivan John M.
Published: December 2020

Finite element analyses of multi-dimensional, partial differential equations require accurate and complete boundary condition assignments. However, continuous temporal and spatial values along physical boundaries are rarely available when solving realistic problems based on field data. To mitigate this situation a neural network system was developed and coupled with an interpolation routine. This innovative computational utility was used to provide continuous boundary condition information in time and space along physical boundaries of interest. The neural network was trained to predict the time response at discrete boundary locations based on field measurements at those locations. Once trained the neural network system was capable of providing a continuous time history for those locations. This system was then linked to an interpolation routine which handled the spatial component of the boundary condition specifications. These coupled routines facilitated rapid deployment and testing of various finite element representations. Further, the neural network system captured the transient physics of the situation more accurately than interpolation routines used previously.
Approximations for Safety Optimization of Large Systems
Authors: Yang R. J. , Gu L. , Liaw L. , Gearhart C. , Tho C. H. , Liu X. , Wang B. P.
Published: December 2020

This paper presents four approximation methods for the construction of safety related functions. These methods are: Enhanced Multivariate Adaptive Regression Splines, Stepwise Regression, Artificial Neural Network, and the Moving Least Square. The optimal Latin Hypercube Sampling method is used to distribute the sampling points uniformly over the entire design space. Four benchmark problems used in crash and occupant simulation are employed to investigate the accuracy of the approximate or surrogate models. An occupant safety optimization problem is solved using these four response surfaces. Based on numerical results, a best, applicable approximation strategy for safety optimization is proposed in the end.
The Tolerance Optimization Problem Using a Near-to-Global Optimum
Authors: Gadallah Mohamed H.
Published: December 2020

In this paper, an algorithm is developed to deal with the discrete optimization problem. The algorithm approximates any design continuous domain with finite number of discrete points and employs single and multi-level search to reach near-to-global optimum. In single level search, one orthogonal array is used to model any given search domain. In multi-level search, two or more orthogonal arrays are coupled in series and used to model the search domain. The number of design levels are increased with the number of arrays via different coefficients. The tolerance synthesis problem with optimum process combination is revisited to compare our method with well-established algorithms such as Simulated Annealing (SA) and Sequential Quadratic Programming (SQP). The effect of algorithm parameters: different structure combinations, reducing move factors, weighing factors and column assignments on optimum for single and multi-level search are investigated. Results indicate the capability of the approach to reach near-to-global optimum in about 5.20%–19.5% of time taken by other methods. A survey of available algorithms is given and the method is validated with few test cases.
Structural Optimization Under Variable Loading Conditions
Authors: Teng Chin-Pun , Angeles Jorge
Published: December 2020

The problem of structural optimization under variable loading conditions is discussed here. We assume a linearly-elastic structure subject to one single load of constant magnitude but of arbitrary orientation. Moreover, we assume that the structure is discretized by finite elements. The result of this study is an optimality criterion: the eigenvalues of the stiffness matrix of the optimum structure observe a minimum variance. In other words, the optimum structure under variable load must have a stiffness matrix that is as close as possible to isotropy. Furthermore, in order to implement the foregoing criterion, we introduce a novel method of automatic mesh generation, that is based on the concept of penalty functions of nonlinear programming. Finally, we illustrate these concepts by means of the optimization of a triangular lamina of given side lengths, with an elliptical hole centered at its centroid, of a prescribed area, the design parameters being the semiaxes of the ellipse and the orientation of these axes with respect to the edges of the lamina.
Design of Robust Interfaces in Modular Products
Authors: Blackenfelt Michael , Sellgren Ulf
Published: December 2020

The design of module interfaces is very important when developing so-called modular products. The interfaces should not only be designed for the module variety but should also be specified early to allow parallel activities. This paper outlines an approach where the interfaces, in the beginning of the process, are defined within some bounds. Later when more information about the modules and their variety is available the interface is conceptualised by topological optimisation and detailed by shape optimisation. The shape optimisation is however complemented with Robust Design technique in order to increase the interface commonality for the variety range.
“Intelligent” Optimal Design
Authors: Zarka Joseph
Published: December 2020

The engineers have to face very important problems in the design, the test, the survey and the maintenance of their structures. These problems did not yet get full answer even from the best people in the world. Usually in these problems (such as no satisfactory constitutive modeling of materials, no real control of the accuracy of the numerical simulations, no real definition of the initial state and/or the effective loading of the structure), there is no solution and the experts do not understand the problem in its whole. Moreover, the available data may be not statistically representative (i.e. are in limited number), fuzzy, qualitative and missing in part.

We propose a practical solution the «Intelligent Optimal Design of Materials and Structures» where the actual best knowledges of the researchers/experts are intelligently mixed to the results of experiments or real returns.
Multi-Objective Optimization of Hydraulic Actuation Systems
Authors: Andersson Johan , Krus Petter , Wallace David
Published: December 2020

Many real world engineering problems are characterized by the presence of several conflicting design objectives. In this paper, a new multi-objective genetic algorithm is employed to optimize two different concepts of hydraulic actuation systems. The different concepts have been modeled in a simulation environment to which the optimization strategy has been coupled.

The outcome from the proposed optimization strategy is a set of Pareto optimal solutions elucidating the tradeoffs between competing objectives. By comparing Pareto frontiers for competing concepts, valuable insights about the properties of the different concepts can be gained. Depending on how the decision-maker values the different objectives, different design solutions are more appropriate. This is exemplified in the hydraulic actuation systems, where the acceptance of a larger control error results in a design with low energy consumption.
Formulation of the Equations of Motion of RRPR Robot Manipulator
Authors: Attia Hazem Ali , El-Mistikawy Tarek M. A. , Megahed Adel A.
Published: December 2020

In this paper the dynamic analysis of RRPR robot manipulator is presented. The equations of motion are formulated using a two-step transformation. Initially, a dynamically equivalent system of particles that replaces the rigid bodies is constructed and then Newton’s second law is applied to derive their equations of motion. The equations of motion are then transformed to the relative joint variables. Use of both Cartesian and joint variables produces an efficient set of equations without loss of generality. For open chains, this process automatically eliminates all of the non-working constraint forces and leads to an efficient solution and integration of the equations of motion. The results of the simulation indicate the simplicity and generality of the dynamic formulation.
An Introduction to the Designers’ Sandpit
Authors: Tate Susan J. , Jared Graham E. M. , Brown Nathaniel J. , Swift Kenneth G.
Published: December 2020

This paper introduces the notion of the Designers’ Sandpit. It presents the proposed user interface, a preliminary view of a Proactive DFA methodology and the geometric reasoning functionality required to support it.

In previous work1 a prototype assembly-oriented design environment incorporating DFA and assembly planning has been developed, integrated with CAD and supported by geometric reasoning algorithms. However, another opportunity to enhance the capabilities of the Sandpit is through the incorporation of functional representations. Functional modelling aims to bridge the gap between conceptual and detailed design and when addressed in a general context is a challenging research subject. Here, a functional modelling approach is proposed in the context of assembly-oriented CAD to facilitate the evaluation of product design in terms of manufacture, assembly and cost, before the geometry is defined.
Design for Variety: A Methodology for Developing Product Platform Architectures
Authors: Martin Mark V. , Ishii Kosuke
Published: December 2020

Developing a robust, product platform architecture brings an important competitive advantage to a company. The major benefit is reduced design effort and time-to-market for future generations of the product. This paper describes a step-by-step method that aids companies in developing such a product platform architecture. Using the concept of specification “flows” within a product development project, the design for variety (DFV) method develops two indices to measure a product’s architecture. The first index is the Generational Variety Index (GVI), a measure for the amount of redesign effort required for future designs of the product. The second index is the Coupling Index (CI), a measure of the coupling among the product components. The design team uses these two indices to develop a decoupled architecture that requires less design effort for follow-on products.
A Model for Information Flow in Design
Authors: Shooter Steven B. , Keirouz Walid T. , Szykman Simon , Fenves Steven
Published: December 2020

The complexity of modern products and design tools has complicated the exchange of design information. It is widely recognized that the capture, storage, and retrieval of design information is one of the major challenges for the next generation of computer aided design tools. This paper presents a model for the flow of design information that supports a semantics-based approach for developing information exchange standards. The model classifies design information into various types, organizes these types into information states and levels of abstraction, and identifies the various transformations that operate between the information states. The model is then applied to an example of a transmission for a cordless drill.
Towards the Synthesis of Aesthetic Product Form
Authors: Smyth Stephen N. , Wallace David R.
Published: December 2020

A method for the synthesis of aesthetic product form is proposed. The approach attempts to bring computation to bear on the notion of brand DNA, a term which is used in industry loosely to refer to the aesthetic form elements that contribute to brand identity. The designer defines the origin of an evolutionary process by interactively describing the archetype, or skeleton, of the desired form based on existing product geometry. The system uses the skeleton to generate a variety of forms, or surface skins. The designer selects appealing surfaces for further evolution in form space. It is envisaged that this synthesis process will be applied within an integrated industrial design cycle that supports the rapid alternation between physical and digital representations of product geometry.
Quantitative Measures for Design by Analogy
Authors: McAdams Daniel A. , Wood Kristin L.
Published: December 2020

In this paper a quantitative measure for design-by-analogy is developed. This measure is based on the functional similarity of products. By using this product similarity measure, designers are able to formalize and quantify design-by-analogy techniques during concept and layout design. The similarity measure and its application is clarified and validated through a case study. The case study is the original design of a pickup winder.
Modular Product Architecture
Authors: Dahmus Jeffrey B. , Gonzalez-Zugasti Javier P. , Otto Kevin N.
Published: December 2020

This paper presents an approach to architecting a family of products that share inter-changeable modules. Rather than a fixed product platform upon which derivative products are created through substitution of various add-on modules, the approach here permits the platform itself to be one of several possible sizes or types. Thus, the system is a collection of modules, each of which can be one of several types. We begin by developing function structures of each product in the portfolio, where each embodies a specific physical principle underlying the common technology. Different function structure systems can be used for each physical principle under consideration. These function structures are then compared to determine common and unique modules. Product modularity rules (i.e. dominant flow, branching, and conversion) are then applied to determine further possible modules. Application of any consistent set of modularity rules defines a feasible portfolio architecture. Each portfolio architecture is represented using a modularity matrix of functions versus products, with shared/unique function levels indicated in the matrix. Possible product modules are indicated with boxes while possible portfolio modules are indicated with shading. This method provides a systematic approach to generating possible portfolio architectures and serves as a communication aid for design team deliberations.
Modified FMEA Using Analysis of Automotive Remanufacturer Waste Streams to Support Design for Remanufacture
Authors: Sherwood M. , Shu L. H.
Published: December 2020

This paper describes the development and use of a modified Failure Modes and Effects Analysis (FMEA) to support design for remanufacture. The results of waste-stream analyses of three automotive remanufacturers were used for this FMEA. The waste streams were assessed to determine factors that impede the reuse of parts. Worn parts that could not be refurbished were found to be the most significant contribution to the waste stream of the automotive remanufacturers studied. The use of the modified FMEA allows consideration of factors such as ease of repair and detection of failure, in conjunction with the mass and part count contribution to the waste stream, to develop priorities in design for remanufacture.
A Design Tool to Help Small Manufacturers Reengineer a Product Family
Authors: Maupin Andrew J. , Stauffer Larry A.
Published: December 2020

Small manufacturers are often less profitable because they introduce new products with little regard for compatibility with other products currently in production. The result is a portfolio of related products with an architecture that lacks company-wide strategic coordination. We present a methodology that can be used by these small manufacturers to reengineer a product family for greater profitability. The methodology is based upon application of four metrics and three design tools that are simple to use and intuitively easy to comprehend. We also present an example of applying this methodology with a small manufacturer to help the reader better understand it. We do not profess that this methodology will produce an optimal product-family architecture but one that will realize most of the potential gains. This process is particularly suitable to small manufacturers (or even larger firms) who are usually short on financial resources and lack a broad range of technical skills.
Circuit and Branch Rectification of the Spatial 4C Mechanism
Authors: Larochelle Pierre M.
Published: December 2020

Spatial 4C mechanisms are two degree of freedom kinematic closed-chains consisting of four rigid links simply connected in series by cylindrical(C) joints. In this work we are concerned with the design of spatial 4C mechanisms which move a rigid body through a finite sequence of prescribed locations in space. This task is referred to as rigid-body guidance by Suh and Radcliffe (20) and as motion generation by Erdman and Sandor (6). When 4C mechanisms are synthesized for such a task, for example by utilizing Roth’s spatial generalization of Burmester’s planar methods (17; 18), the result is the physical dimensions which kinematically define the mechanism. However, the motion of the mechanism which takes the workpiece through the sequence of prescribed locations in space is not determined. In fact, it may be impossible for the mechanism to move the body through all of the desired locations without disassembling the mechanism. This condition is referred to as a circuit defect. Moreover, in some cases the mechanism may enter a configuration which requires an additional mechanical input to guide the moving body as desired. These are referred to as branch defects. This paper presents a methodology for analyzing spatial 4C mechanisms to eliminate circuit and branch defects in motion generation tasks.
A Model for Study of Stick-Slip Vibrations in Caliper-Disc Brake Systems
Authors: Meinhardt Glenn , Farhang Kambiz
Published: December 2020

Friction-induced vibration in caliper-disc brake systems is examined using mathematical formulations based on the lumped-parameter approach. The theoretical treatment of the system considers the kinematic and dynamic properties of the caliper motion, accounting for the slider translation and flexure as well as rotational stiffness of the caliper assembly. In addition, compressive and shear properties of the friction material is included in the derivation of the model. The geometric and material/friction coupling effects are also included in the model. The geometric coupling effects arise from the kinematic nature of the caliper-disc brake system. The material/friction coupling effects are due to the compressive properties of the pad friction material leading to the determination of instantaneous pad/rotor average pressure and, thereby, its influence on the transmitted braking torque due to frictional contact. The coefficients of friction of the pad are represented by an exponential function (Larsson and Farhang, 1997) that describes the decay from the static friction coefficient to the kinetic friction coefficient as the relative velocity between the pad and rotor is increased. The resulting equations of motion are a set of second-order ordinary differential equations. Results are presented using an initial vehicle speed of 55 miles per hour.
On the Overhung Rigid Rotor Balancing
Authors: Méndez-Adriani José A.
Published: December 2020

This article develops a more efficient technique for the balancing of the overhung rigid rotor, which is a variation of the exact influence coefficient method, that gives directly the correction weights for both balancing planes. During the calibration process, one trial weight is used for the second run and, to reduce the cross effect, only one trial weight to form a couple is used for the third run, improving the field balancing method for maintenance works.
On the Separability of the Solutions of the Direct Kinematics of a Special Class of Planar 3-RPR Parallel Manipulator
Authors: Merlet J.-P.
Published: December 2020

Parallel manipulators have in general multiple solutions for the forward kinematics. In practice however from the control viewpoint only the current pose of the manipulator is of interest. We consider here a special class of planar parallel manipulator and explain how the solution corresponding to the current pose may be distinguished using a singularity criteria.
Manipulator Calibration Using a Single Endpoint Contact Constraint
Authors: Meggiolaro Marco A. , Scriffignano Guglielmo , Dubowsky Steven
Published: December 2020

Most manipulator calibration techniques require expensive and/or complicated pose measuring devices, such as theodolites. This paper investigates a calibration method where the manipulator endpoint is constrained to a single contact point and executes self-motions. From the easily measured joint angle readings, and an identification model, the manipulator is calibrated. Adding a wrist force sensor allows for the calibration of elastic effects due to end-point forces and moments. Optimization of the procedure is discussed. Experimental results are presented, showing the effectiveness of the method.
Identification of Compliant Pseudo-Rigid-Body Mechanism Configurations Resulting in Bistable Behavior
Authors: Jensen Brian D. , Howell Larry L.
Published: December 2020

Bistable mechanisms, which have two stable equilibria within their range of motion, are important parts of a wide variety of systems, such as closures, valves, switches, and clasps. Compliant bistable mechanisms present design challenges because the mechanism’s energy storage and motion characteristics are strongly coupled and must be considered simultaneously. This paper studies compliant bistable mechanisms which may be modeled as four-link mechanisms with a torsional spring at one joint. Theory is developed to predict compliant and rigid-body mechanism configurations which guarantee bistable behavior. With this knowledge, designers can largely uncouple the motion and energy storage requirements of a bistable mechanism design problem. Examples demonstrate the power of the theory in bistable mechanism design.
Development of Equipment for Transfer to Save Manpower for Nursing
Authors: Ohashi Kota , Suzuki Naoto , Miyauchi Kenichi , Katagiri Kazuo , Dohi Takeyoshi , Tsuji Takayuki , Masamune Ken , Sakuma Ichiro , Inada Hiroshi , Suzuki Makoto , Mitsui Kazuyuki
Published: December 2020

Because of the rapid increasing number of the elderly, the shortage of helpers and the burden to helpers is becoming a big problem in our country. Caring work involves many simple physical tasks, and particularly, transferring between a bed and a stretcher, between a bed and a wheelchair, and so on, is heavy burden to helpers. So, many kind of tools and equipment are in practical use. But, actually, it can’t be said that the equipment for transfer which is easy to use from the point of saving manpower, the time required, storage space, efficiency, comfort for patients and user-interface has developed.

In this research, we developed a practical transfer equipment to save manpower for nursing. By moving its plate right and left, this equipment can transfer an elderly person from the bed to the stretcher directly, and decrease time-waste switches and the burden to helpers. Moreover, patients can be transferred without changes of postures.

First, we produced a prototype which has 1/3 length of full size (1800mm), and evaluated the mechanical behavior and the time required. As a result, we found that it takes about 2 minutes to fulfill the task. This result indicates that our developed equipment has a possibility to be used in practical use.
Extensional Stiffness Loss of Synchronous-Belt Cords
Authors: Iizuka Hiroshi , Takahashi Hideo
Published: December 2020

Synchronous belts consist of a rubber, a facing fabric and a helical cord that reinforces the belt stiffness. Therefore, the fatigue failure of the helical cord through the life is important for the stiffness loss of the belts. The purpose of this study is to discuss the mechanism of the extensional stiffness loss of the helical cord during the bending fatigue. The experimental results show that the extensional stiffness reduces up to about 50–60% of the initial value by the accumulation of the bending fatigue damage. The main damage is the de-bonding along the interfaces of the stranded glass filaments in the cord. The three dimensional FEM results show that the extensional stiffness is reduced by the initiation of the de-bonding. Then a simplified mechanical model is proposed to explain the stiffness loss considering the de-bonding. The model reasonably well explains the extensional stiffness loss.
Reducing Gear Windage Losses From High Speed Gears
Authors: Winfree Don D.
Published: December 2020

Windage losses in gearboxes account for a large portion of the total power loss in high-speed drive trains. Very little actual data has been collected specifically quantifying these losses. Traditional techniques to measure the effects of baffles in high speed gearing applications have been done by trial and error on very complex systems. This trial and error technique is used throughout the gearing industry to solve problems without isolating each individual gear windage effect. These solutions are usually sub-optimum. They cause time-consuming delays and cost overruns in many programs. This paper describes a gear baffle test rig that was built to quantify and minimize the gear windage losses in high-speed drive trains. These tests were conducted at the Lockheed Martin Aeronautics Company, Fort Worth Texas Facility. The intent of the gearbox baffle test rig was to isolate and measure the windage effects on a single high-speed bevel gear with various baffle configurations. Results of these tests were used to define a basic set of ground rules for designing baffles. Finally the set of ground rules was used to design an optimum baffle configuration.
Characterization of 3-Dimensional Tooth Flank Topography of Gears
Authors: Kurokawa Syuhei , Pfeifer Tilo , Meyer Stefan
Published: December 2020

The purpose of this research is to derive the meaningful parameters and the new procedure of measurement of tooth flank topography to evaluate the individual gear accuracy objectively. The tooth flank topography is characterized as the curved surface and the parameters for global tooth flank topography are obtained from the 3-dimensional measured deviations of tooth flanks with profile modification, crowning and manufacturing errors. The idea of separation of tooth flank topography into three global form deviations, that is, the 0th, the 1st and the 2nd order form deviations, and the residuals is proposed. In addition, the complete parameters for three global form deviations have been derived mathematically. As a result, the parameters for arbitrary global form deviations and the new definition of the pitch error have been obtained.

As an example, actual bevel gear flanks have been measured with CMM. The developed simulation program has calculated the concrete global parameters for their topographies with measured and nominal data. The results have shown the validity of separation procedure and the derived global parameters. Especially, with respect to the 2nd order form deviations, the parameters, from which we can easily imagine the principal curvature and the anisotropy of global topography, have been obtained. Those global parameters are also useful to characterize tooth profile modification and crowning.
Diagnostic Reliability in Environmental Technology
Authors: Drakatos Panagiotis A.
Published: December 2020

The successful design of environmental technology is characterized by the degree of diagnostic reliability when such reliability is adapted to the processes of the environment. An analysis of the various phases of these environmental processes indicates that the diagnostic reliability of environmental technology must be improved considerably if a sustainable development of human society concurrently with the protection of the environment is to occur.

In order for humanity to succeed in this task, its coexistence with the environment philosophy must be based upon ethical principles; only then will environmental technology prove to be a significant factor in human progress.
Improved recovery of cryopreserved cell monolayers with a hyaluronic acid surface treatment
Authors: Kirby Giles T. S. , Mills Stuart J. , Mueller Tanja E. , Ting Anthony E. , Cowin Allison J. , Michelmore Andrew , Smith Louise
Published: December 2020

Cryopreservation is an essential part of tissue banking and effective cryopreservation methods are critical for the development of cost-effective cell therapy products. Cell sheets are an attractive subset of cell therapy types, and cryopreservation has the potential to further drive down costs of allogeneic cell sheet therapy. This is currently a challenge as adhered cell monolayers are more susceptible to membrane damage during the freezing process. In this article, we investigate the performance of a surface-modified dressing for the cryopreservation of cells and strategies to improve cell recovery. Cryopreservation of multipotent adult progenitor cells (MAPC®) was performed on cells following their attachment to a surface for different periods of time. MAPC cells, given just 1 h to attach, washed off and were not recovered on the surface following thawing. Cells attached for longer periods, elongated further, and were more susceptible to damage from cryopreservation. A temporal window was identified that could allow cryopreservation on adherent surfaces where cells had attached to a surface without full elongation. By functionalizing the surface with coupled hyaluronic acid, cell spreading was initially retarded, thereby widening this temporal window. This approach demonstrates a novel method for enhancing the recovery of cryopreserved cell sheets on surfaces.
Replica molding of cicada wings: The role of water at point of synthesis on nanostructure feature size
Authors: Flynn Shauna P. , Daniels Stephen , Rodriguez Brian J. , Kelleher Susan M.
Published: December 2020

Many natural surfaces, including the wings of cicada insects, have shown to display bactericidal properties as a result of surface topography. Moreover, the size and distribution of the surface features (on the nano- and microscale) are known to influence the efficacy of the surface at inhibiting bacterial cell growth. While these types of natural surfaces illustrate the effect of structure on the bactericidal activity, a deeper understanding can be achieved by creating surfaces of different feature sizes. This is essential in order to understand the effects of changes of surface topography on bacteria-surface interactions. To this end, we have performed a series of replica molding processes of the wings of the Megapomponia Intermedia cicada to prepare wing replicas in polyethylene glycol (PEG), which possess the topographical features of the wing surface, with a minimum loss of feature resolution. Atomic force microscopy characterization of these patterned surfaces in both air and aqueous environments shows that by controlling the swelling characteristics of the PEG, we can control the ultimate swollen dimensions of the nanopillar structures on the surface of PEG. As a result, by using a single wing with an average nanopillar height of 220 nm, different patterned PEG samples with nanopillar heights ranging from 180 to 307 nm were produced.
Piperaquine Pharmacokinetics during Intermittent Preventive Treatment for Malaria in Pregnancy
Authors: Chotsiri Palang , Gutman Julie R. , Ahmed Rukhsana , Poespoprodjo Jeanne Rini , Syafruddin Din , Khairallah Carole , Asih Puji B. S. , L’lanziva Anne , Otieno Kephas , Kariuki Simon , Ouma Peter , Were Vincent , Katana Abraham , Price Ric N. , Desai Meghna , ter Kuile Feiko O. , Tarning Joel
Published: December 2020

Dihydroartemisinin-piperaquine (DP) is a long-acting artemisinin combination treatment that provides effective chemoprevention and has been proposed as an alternative antimalarial drug for intermittent preventive therapy in pregnancy (IPTp). Several pharmacokinetic studies have shown that dose adjustment may not be needed for the treatment of malaria in pregnancy with DP.
A Large Tn
7
-like Transposon Confers Hyperresistance to Copper in
Pseudomonas syringae
pv. syringae
Authors: Aprile Francesca , Heredia-Ponce Zaira , Cazorla Francisco M. , de Vicente Antonio , Gutiérrez-Barranquero José A.
Published: December 2020

Copper compounds have traditionally been used as standard bactericides in agriculture in the past few decades. However, the extensive use of copper has fostered the evolution of bacterial copper resistance mechanisms.
Pseudomonas syringae
is a plant-pathogenic bacterium used worldwide as a model to study plant-pathogen interactions.
Fifteen-minute consultation: Fractures in non-ambulant children with cerebral palsy
Authors: Debelle Geoff , Morris Helen , Shaw Nick , Oates Adam
Published: December 2020

Objective

To describe a safeguarding decision pathway for the assessment of osteopenic fractures in non-ambulant children with cerebral palsy.

Method

Literature review and consensus practice of a child safeguarding team, including clinicians and social workers.

Conclusion

Low-energy fractures of the lower limb in non-ambulant children with cerebral palsy are relatively common and explained by the presence of reduced bone strength, in the absence of any other unexplained injuries or safeguarding concerns.
Association between Goal-Striving Stress and Rapid Kidney Function Decline among African Americans: The Jackson Heart Study
Authors: Cain-Shields Loretta , Glover LáShauntá , Young Bessie , Sims Mario
Published: December 2020

African Americans (AAs) are disproportionately affected by kidney disease and also report higher psychosocial stressors than other racial groups. Goal-striving stress (GSS) is an understudied psychosocial stressor related to attempting to accomplish one's life goals. Given the numerous social determinants that contribute to health inequities among AAs, stress from goal striving may also disproportionately affect the health of AAs and in particular kidney disease outcomes. The objective of this study was to explore the association between GSS and rapid kidney function decline (RKFD) in an AA cohort. Using examination 1 (2000-2004) and examination 3 (2009-2013) data from the Jackson Heart Study (n=2630), we examined associations of baseline levels of GSS with RKFD among AAs using multivariable Poisson regression models, adjusting for sociodemographics, health behaviors, chronic disease and discrimination. We also explored baseline cortisol as a mediator. The incidence of RKFD in this sample was 7.34% (mean years of follow-up: 8.06±0.84 years). The mean GSS score was 3.80 (±4.88) and total GSS score ranged from 0 to 36. Those who reported high (vs low) GSS were 1.60 times more likely to experience RKFD after full adjustment (incidence rate ratio (IRR) 1.60; 95% CI 1.11 to 2.14, p=0.01). After confirming cortisol as a mediator and adding it to the model, those who reported high (vs low) GSS had 1.58 times the rate of RKFD (IRR 1.58; 95% CI 1.09 to 2.30, p=0.0153). Stress related to not achieving goals was associated with a greater risk of RKFD in this sample of AAs.
Intraoperative vascular complications during 2278 cerebral endovascular procedures with multimodality IONM: relationship between signal change, complication, intervention and postoperative outcome
Authors: Wilent W Bryan , Belyakina Olga , Korsgaard Eric , Tjoumakaris Stavropoula I , Gooch M Reid , Jabbour Pascal , Rosenwasser Robert , English Joey D , Kim Warren , Tesdahl Eric , Cohen Jeffrey , Sestokas Anthony K
Published: December 2020

Background

Intraoperative neuromonitoring (IONM) is often used during cerebral endovascular procedures.

Objective

To investigate the relationship between intraoperative vascular complications and IONM signal changes, and the impact of interventions on signal resolution and postoperative outcomes.

Methods

A series of 2278 cerebral endovascular procedures conducted under general anesthesia and using electroencephalography and somatosensory evoked potential monitoring were retrospectively reviewed. A subset of 763 procedures also included motor evoked potentials (MEPs). IONM alerts were categorized as either a partial attenuation or complete loss of signal. Vascular complications were subcategorized as due to rupture, emboli, instrumentation, or vasospasm. Odds ratios (ORs) for new postoperative motor deficits were calculated and diagnostic accuracy was measured using sensitivity, specificity, and likelihood ratios.

Results

The overall incidence of new postoperative motor deficit was 1.2%; 20.4% in cases with an IONM alert and 0.09% in cases without an alert. Relative to procedures with no alerts, odds of a new deficit increased if there was partial signal attenuation (OR=210.9, 95% CI 44.3 to 1003.5, p<0.0001) and increased further with complete loss of signal (OR=1437.3, 95% CI 297.3 to 6948.2, p<0.0001). Relative to procedures with unresolved alerts, odds of a new deficit decreased if the alert was fully resolved (OR=0.039, 95% CI 0.005 to 0.306, p<0.002). Procedures using MEPs had slightly higher sensitivity (92.3% vs 85.7%) but slightly lower specificity (96.7% vs 98.2%).

Conclusions

An IONM alert associated with an arterial complication is associated with a dramatic increase in odds of a new postoperative deficit; however, if there is resolution of the alert prior to closure, odds of a new deficit decrease significantly.
Comparison of Woven EndoBridge device sizing with conventional measurements and virtual simulation using the Sim&Size software: a multicenter experience
Authors: Cagnazzo Federico , Marnat Gaultier , Ferreira Ivan , Daube Pierre , Derraz Imad , Dargazanli Cyril , Lefevre Pierre-Henri , Gascou Gregory , Riquelme Carlos , Morganti Riccardo , Berge Jérôme , Gariel Florent , Barreau Xavier , Costalat Vincent
Published: December 2020

Background

Selection of the appropriate device size mandatory during aneurysm treatment with a Woven EndoBridge (WEB). We aimed to investigate if virtual simulation with Sim&Size software may have an impact on technical, angiographic, and clinical outcomes after WEB treatment.

Methods

Data from two large-volume centers were collected and compared (January 2017–January 2020). Virtual simulation was systematically adopted in one center, while conventional sizing was used in the other one. Outcomes were the duration of intervention, the radiation dose (in milligrays, the number of corrective interventions for inappropriate WEB size, the number of WEBs not deployed, angiographic occlusion, and complications. Univariate and multivariate linear models were adopted.

Results

A total of 186 aneurysms were treated with WEB (109 with and 77 without virtual simulation). Patient characteristics and aneurysm features were comparable among virtual and conventional sizing, except for mean age (62.2±11.8 years and 56.2±10.1 years, P=0.0004) and median aspect ratio (1.6, IQR=1.2–2 and 1.2, IQR=1–1.6, P=0.0001). Years of operator experience were comparable. Virtual simulation was independently associated with shorter intervention time (45 min, IQR=33–63.5 min vs 63.5 min, IQR=41–84.7 min, P=0.0001), lower radiation dose (1051 mGy, IQR=815–1399 mGy vs 1207 mGy, IQR=898–2084 mGy, P=0.0001), and lower number of WEBs not deployed (26/77=33.7% vs 8/109=7.3%, P=0.0001). The need for additional maneuvers was significantly lower in the virtual simulation group (5/109=4.6% vs 12/77=15.6%, P=0.021). Angiographic outcomes and complications were comparable.

Conclusions

In this multicenter experience, virtual simulation with Sim&Size software seems to facilitate the selection of the appropriate WEB device for aneurysm treatment, reducing the time of intervention, the radiation dose, the number of devices not deployed, and the need for corrective interventions.

Trial registration number

clinicaltrials.gov Identifier:NCT04621552.
Spinal NR2B phosphorylation at Tyr1472 regulates IRE(−)DMT1-mediated iron accumulation and spine morphogenesis via kalirin-7 in tibial fracture-associated postoperative pain after orthopedic surgery in female mice
Authors: Zhang Linlin , Wang Zhen , Song Chengcheng , Liu Haoyu , Li Yize , Li Jing , Yu Yonghao , Wang Guolin , Cui Wei
Published: December 2020

Background

Prolonged postoperative pain is a major concern and occurs more frequently in women, but mechanisms remain elusive. NR2B-containging N-methyl-d-aspartate (NMDA) receptor is a key component of nociception transduction. Divalent metal transporter 1 (DMT1)-mediated iron overload involves NMDA-induced neurotoxicity in males. Kalirin-7 is vital in synaptic plasticity underlying pathological pain in males. Herein, the requirement for kalirin-7 in NR2B phosphorylation-dependent iron accumulation and spine plasticity in postoperative pain after tibial fracture in female mice has been examined.

Methods

Pain-related behavior, spinal NR2B phosphorylation at Tyr1472, kalirin-7 expression, DMT1 with/without iron-responsive element (IRE (+) DMT1 and IRE (−) DMT1) level, iron concentration and spine morphology were assessed in females. NR2B antagonist Ro25-6981, iron chelator deferoxamine and kalirin-7 knockdown by short hairpin RNA were employed to assess the potential cascade.

Results

Tibial fracture initiates long-term allodynia lasting at least 21 days postoperatively, and upregulates spinal NR2B phosphorylation, kalirin-7 and IRE (−) DMT1 expression, iron overload and spine density. Ro25-6981 reduces postoperative mechanical and cold allodynia, spinal NR2B phosphorylation, kalirin-7 level and IRE (−) DMT1-mediated iron overload. Kalirin-7 knockdown impairs fracture-associated allodynia, IRE (−) DMT1-mediated iron overload and spine plasticity. Deferoxamine also attenuates behavioral allodynia and spine plasticity. Spinal NMDA application elicits NR2B-dependent mechanical allodynia and iron overload, which is reversed by kalirin-7 knockdown or coadministration of deferoxamine.

Conclusion

Spinal NR2B phosphorylation at Tyr1472 upregulates kalirin-7 expression to facilitate IRE (−) DMT1-mediated iron accumulation and spine morphogenesis in the development of fracture-associated postoperative pain in female mice.
Spinal and paraspinal inflammatory reactions after epidural steroid injection in a patient taking disease-modifying antirheumatic drugs
Authors: Patel Prachi M , Lam Isaac , Liu Benjamin P , Benzon Honorio T
Published: December 2020

Background

Disease-modifying anti-rheumatic drugs (DMARDs) are used in the management of rheumatoid arthritis (RA) and are classified as conventional DMARDs and biologic agents. A concern with DMARDs is the increased risk of infection after surgery. A practice advisory from the American Society of Anesthesiologists recommend alternatives to neuraxial injections in patients who are immunocompromized. We describe a patient who was on several DMARDs and developed inflammatory reactions in her bilateral paraspinal muscles and lumbar spine after an epidural steroid injection (ESI).

Case presentation

The patient was a 79-year-old woman; she was taking methotrexate, adalimumab and prednisone for her RA. She had a left L5-S1 paramedian ESI for her L5 radiculitis. After relief of her back and radicular pain for 5 weeks, she had an acute exacerbation of her back pain. MRI showed bilateral paraspinal fluid accumulations and enhancement in her ligamentum flavum. Cultures of the aspirated fluid and biopsy specimens were negative for fungal, aerobic and anaerobic organisms. A repeat MRI 2 months later showed diminution of the fluid collection but with a new fluid accumulation near the left L4-5 facet and left L4 pedicle. Repeat cultures and gram stain of the specimens taken from the pedicle and the paraspinal muscles were negative. The patient was followed by her rheumatologist and in the pain clinic until resolution of her symptoms.

Conclusions

Several society guidelines recommend the continuation of methotrexate but stoppage of the biologic DMARDS before surgery. The occurrence of an intense inflammatory reaction after an ESI in our patient calls for additional research on the subject and shared decision-making between the pain physician, patient and rheumatologist especially in patients on several DMARDs.
Managing intensive care admissions when there are not enough beds during the COVID-19 pandemic: a systematic review
Authors: Tyrrell Carina S B , Mytton Oliver T , Gentry Sarah V , Thomas-Meyer Molly , Allen John Lee Y , Narula Antony A , McGrath Brendan , Lupton Martin , Broadbent Jo , Ahmed Aliko , Mavrodaris Angelique , Abdul Pari Anees Ahmed
Published: December 2020

The surge in cases of severe COVID-19 has resulted in clinicians triaging intensive care unit (ICU) admissions in places where demand has exceeded capacity. In order to assist difficult triage decisions, clinicians require clear guidelines on how to prioritise patients. Existing guidelines show significant variability in their development, interpretation, implementation and an urgent need for a robust synthesis of published guidance. To understand how to manage which patients are admitted to ICU, and receive mechanical ventilatory support, during periods of high demand during the COVID-19 pandemic, a systematic review was performed. Databases of indexed literature (Medline, Embase, Web of Science, and Global Health) and grey literature (Google.com and MedRxiv), published from 1 January until 2 April 2020, were searched. Search terms included synonyms of COVID-19, ICU, ventilation, and triage. Only formal written guidelines were included. There were no exclusion criteria based on geographical location or publication language. Quality appraisal of the guidelines was performed using the Appraisal of Guidelines for Research and Evaluation Instrument II (AGREE II) and the Appraisal of Guidelines for Research and Evaluation Instrument Recommendation EXcellence (AGREE REX) appraisal tools, and key themes related to triage were extracted using narrative synthesis. Of 1902 unique records identified, nine relevant guidelines were included. Six guidelines were national or transnational level guidance (UK, Switzerland, Belgium, Australia and New Zealand, Italy, and Sri Lanka), with one state level (Kansas, USA), one international (Extracorporeal Life Support Organization) and one specific to military hospitals (Department of Defense, USA). The guidelines covered several broad themes: use of ethical frameworks, criteria for ICU admission and discharge, adaptation of criteria as demand changes, equality across health conditions and healthcare systems, decision-making processes, communication of decisions, and guideline development processes. We have synthesised the current guidelines and identified the different approaches taken globally to manage the triage of intensive care resources during the COVID-19 pandemic. There is limited consensus on how to allocate the finite resource of ICU beds and ventilators, and a lack of high-quality evidence and guidelines on resource allocation during the pandemic. We have developed a set of factors to consider when developing guidelines for managing intensive care admissions, and outlined implications for clinical leads and local implementation.