bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing Variety in Product Families Through Design for Commonality
Authors: Kota Sridhar , Sethuraman Kannan
Published: February 2021

Majority of companies develop a family of products and many new product variations are added to the product portfolio regularly to meet changing market needs and/or to attract new customer base. Although, the core functionality remains essentially unchanged across all products within a family, new functions, new feature combinations and new technologies are incorporated into each new product. The component variations, commonly referred to as “complexity”, grow exponentially resulting in loss of productivity and/or quality. The challenge lies in effective management of product variations in the design studies and on the manufacturing floor. The key is to minimize non-value added variations across models within a product family without limiting customer choices. Although the benefits of standardization are widely known and most companies do standardize stock components such as fasteners, they are far from standardizing their product -specific core components and thus fail to reap significant benefits in quality and cost. Through this research, we are developing new methodologies for improved management of product variety to achieve higher productivity.

In this paper, we discuss the factors that contribute to product complexity in general, and present an objective measure, called the Product Line Commonality Index, to capture the level of part commonality in a product family. Through our Walkman case study, we illustrate robust design/manufacturing strategies, including modularity and postponement of product differentiation, that help minimize non-value added variation across models within a product family1 without limiting customer choices. Finally, we present a simple and yet a powerful method of benchmarking product families or companies in their ability to share parts effectively (modularity) and reduce the total number of parts (multi-functionality) used in product families.
The Structure of Designs
Authors: Earl C. F.
Published: February 2021

The role of design descriptions is reviewed particularly in providing connections between product and process. The relations among the parts of descriptions represent the structure of designs. We consider the particular case when the parts form a closure structure and derive conclusions about the topology of descriptions. Following the scheme adopted for shapes and shape grammars we show that closure structures are a direct consequence of the primary role of relations in descriptions. Design processes use descriptions both individually and in combination. The different descriptions of a design display a partial order. It is shown how to combine descriptions into new descriptions. Further, multiple attribute descriptions including, for example, shape and associated properties, are constructed. Their structures are represented algebraically.
The Engineering Design Discipline: Is its Confounding Lexicon Hindering its Evolution?
Authors: Messac Achille , Chen Wei
Published: February 2021

In this paper, we invite the engineering design research community to examine the current state of the engineering design lexicon. We expose the nature and the pervasiveness of practices that often hinder intelligible discourse within the engineering design literature. In particular, we show how such commonly used terms as criterion and metric are used sometimes as synonyms and sometimes not, often leading to material miscommunications. In our view, the engineering design discipline has reached a point in its evolution where clarity and conciseness of its lexicon should be a priority. Today’s design activity takes place in a truly multidisciplinary environment, which often involves engineers of diverse backgrounds. Written and oral design discourse among design researchers does not rely on a generally accepted and documented lexicon. These situations are symptomatic of a communication infrastructure that is not effectively facilitating the vigorous evolution of the engineering design discipline of recent years. In addition to detailing the outlines of the design lexicon deficiency, we also propose some avenues to a constructive and productive community-wide discussion on this subject. We invite readers to contribute their views by participating in the web discussion at http://www.eng.buffalo.edu/Research/DBD/.
Classification of Iteration in Engineering Design Processes
Authors: Safoutin Michael J. , Smith Robert P.
Published: February 2021

As engineering design is subjected to increasingly formal study, an informal attitude continues to surround the topic of iteration. Today there is no standard definition or typology of iteration, no grounding theory, few metrics, and a poor understanding of its role in the design process. Existing literature provides little guidance in investigating issues of design that might be best approached in terms of iteration. We review contributions of existing literature toward the understanding of iteration in design, develop a classification of design iteration, compare iterative aspects of human and automated design, and draw some conclusions concerning management of iteration and approaches to design automation.
Modular Automation Concepts: Opportunities and Challenges in Industry
Authors: Derby Stephen , Cooper Clay
Published: February 2021

The goals of Modular Automation Concepts (MAC) for the automation field are presented. In order to demonstrate the strategies, the packaging automation industry is reviewed to find new opportunities for production machines. These new machines were designed with the MAC techniques. Other challenges from the industrial side to Modular Design are also discussed.
Uncertainty Analysis of Planar Robots With Joint Clearance
Authors: Zhu Jianmin , Ting Kwun-Lon
Published: February 2021

Joint clearance in mechanisms and robots leads to uncertainty in function deviation. Unlike the impact of the link tolerance on the performance quality, the uncertain effect of the joint clearance to the performance can not be eliminated by calibration because of the random nature. In this paper, based on the probability theory, a general probability density function for the output of planar robots is established for any probability density function of joint clearance. The result is demonstrated by a uniform distribution in the joint clearance and a table of the resulting functions is presented. These distribution functions and the table provide a convenient way to obtain the probability value for a planar robot to position its end point within a desired deviation zone and to determine the joint clearance value based on the concerned shape of tolerance zone and the specified probability value of repeatability.
Dynamic Response of Two-Disk Systems With Friction and Misalignment
Authors: Anabtawi Ahmed , Farhang Kambiz
Published: February 2021

Friction induced vibration and noise pose one of the most challenging problems. The complexity of the friction system arises due to the nonlinear nature of friction phenomena and that of contact stiffness and damping. This paper presents a mathematical model for studying the dynamic response of two-disk friction system in the presence of misalignment. The contact stiffness and damping characteristics of the system are represented in the axial as well as the torsional directions. In addition, the axial and torsional responses of the system are coupled by assuming dependency between the torsional response and the normal force between the two disks.

Using the mathematical model, various scenarios are examined to study the effect of misalignment. These include cases of symmetric and asymmetric actuation forces as well as forces applied at unequal actuation times. The results suggest that asymmetry in actuation forces has negligible effect on stick-slip behavior of the system.
Dynamic Characteristics Analysis of an Escalator Using the Computational Dynamics Program
Authors: Kwon Yi Sug , Park Chan Jong
Published: February 2021

Predicting dynamic characteristics of an escalator by means of the computational dynamic analysis is a meaningful subject, and has not been thoroughly investigated before. The general purposed kinematic and dynamic analysis program, DADS which has been shown to be effective in the dynamic analysis of multi-body, is utilized to analyze the interaction of the escalator to be more than 900 independent degree-of-freedom. Thousands of friction contact elements are applied to correctly simulate impact, permanent contact and temporary contact of rollers and the handrail. The presented model is experimentally verified to substantiate the accuracy and efficacy.
Systematic Design of Mechanical Devices
Authors: Jensen Preben W.
Published: February 2021

Structural analysis and type synthesis (joint substitution) is a prerequisite for the systematic development of mechanisms. However, the design of mechanical devices requires first a consideration of whether there is a fixed member or not (as by hand-held devices) and then a differentiation between at least two input and two output members (links). The subject of hand-held tools requires an expanded (and correct) definition of a mechanism because no link is fixed (although they are mechanisms in the true sense of the word). Open as well as combined open and closed kinematic chains must be included in the definition of mechanisms. This approach leads to the creation of new devices that cannot be obtained with known methods. This approach also allows a closer look at existing devices. The intuitive approach, even for one who is very familiar with linkage mechanisms, will in general not lead to the goal of choosing the input and output links in an optimal way. The development requires an overhaul of the usual definition of a mechanism.
On the Contact Sequences of Roller Gear Cam Mechanisms
Authors: Chen Hsin-Hung , Yan Hong-Sen
Published: February 2021

This paper, we discuss various contact situations of roller gear cam mechanisms. Rules for determining the contact sequences of groove-traveling and rib-riding roller gear cam mechanisms are concluded. Differences of the contact sequences between roller gear cam mechanisms with and without preload are pointed out based on Newton’s law. An industrial application is presented as an example to illustrate how to use these rules for determining contact sequences of groove-traveling roller gear cam mechanisms. The result facilitates calculating processes both in the CAD/CAM of roller gear cam mechanisms.
Analysis of Geometric Parameters of the Tool Which Ensure the Maximum Gear Tooth Profile Accuracy
Authors: Podzharov Evgueni I.
Published: February 2021

An analysis of possibilities for the selection of tool geometry parameters was made to reduce tooth profile errors during grinding of gears by different methods. The selection of parameters was based on the analysis of the grid diagram of a gear and a rack. Some formulas and graphs are presented for the selection of the pressure angle, module and addendum of the rack-tool. The results of grinding of experimental gears confirm the theoretical analysis.
The Angle of Pressure in the Chain-Wave Transmission and the Optimum Number of Teeth of its Sprockets
Authors: Amiryan Ara K.
Published: February 2021

This paper is about the chain-wave transmission (CWT), that is a new kind of harmonic drives. The objective of this work is the determination of the angle of pressure in chain-wave mechanisms and the investigation to find the constraint between the angle of pressure and geometrical parameters of the CWT. In the first part are described also objectives for the creation of the chain-wave transmission and main advantages of its construction. It is determined the angle of pressure on the basis of dynamic syntheses of the chain-wave mechanism. The compression factor of the form of the wave generator is taken as a geometric parameter, which is influence upon the angle of pressure. It is determined also that the compression factor depends on number of teeth of the interacting sprocket and on factor of multiplicity of the CWT and it is necessary to limit their values at designing of chain-wave mechanisms.
Four-Link Anti-Squat and Drag Racing Motorcycle Performance: A Parametric Study
Authors: Wiers Paul C. , Dhingra A. K.
Published: February 2021

Anti-squat is a transient vehicle suspension parameter which can dramatically affect tractive effort available at motorcycle drive tire. In the drag racing environment, maximizing tractive effort is essential to competitive performance. Tuning a four-link rear suspension to provide anti-squat increases rear tire traction at the starting line, which increases tractive effort and vehicle acceleration performance. Minimization of the time required to initiate and maintain forward acceleration, often considered the most important part of a drag race, enables peak overall race performance to be realized. Utilizing PC based CAD, finite element analysis, and dynamic system analysis software, a motorcycle rear suspension system was designed, built and tested under actual racing conditions. Parametric studies using dynamic theoretical models were conducted for both unsuspended and four-link equipped versions of the same vehicle. Results and conclusions are presented. Based on the results, it is shown the four-link suspension, when applied to a drag racing motorcycle, does provide opportunity for improving tractive effort at the beginning of a race which will improve overall drag racing performance.
The Design Implications of Chaotic and Near-Chaotic Vibrations in Machines
Authors: Gu Pengyun , Dubowsky Steven , Mavroidis Constantinos
Published: February 2021

Accurate performance prediction is key to the design of high performance machines. It is shown here that connection clearance and component flexibility can result in machine dynamic behaviors that are hypersensitive to small variations of system design parameters and operating conditions. These hypersensitivities, which can limit the usefulness of computer dynamic simulations for design, are associated with chaotic and near chaotic behavior. The dynamic behaviors of two systems, an Impact Beam System and a Spatial Slider Crank, are studied. The chaotic vibration of these systems is confirmed numerically and experimentally. Hypersensitivity is shown for both chaotic and periodic response regions, in which case actual dynamic behavior of such machines could be very different in practice from that predicated by design simulation studies. Design guidelines are developed for evaluating the fatigue life and the reliability of machines under these conditions.
Contact Force Analysis in an OHC Finger-Follower-Type Cam-Valve System With Different Dynamic Models
Authors: Liu Xiaoming , Ling Zhi-Kui
Published: February 2021

This study uses various dynamic models to predict contact forces in a finger-follower-type cam-valve system. It is found that the following factors have the greatest impact on the overall behavior of a cam valve system. They are the cam profile, valve spring, and rocker arm ratio. In this study, different techniques in modeling cam profiles are explored. Various ways of modeling valve-springs are examined. The rocker-arm ratio is assumed to be either a nonlinear function or a constant. Since the speed of the cam dictates a great deal in the overall behavior of the system, three different cam speeds are tested in this study. The models used in this study are established with a constructive approach by using a commercially available software system.
A Simple and Accurate Method for Determining Large Deflections in Complaint Mechanisms Subjected to End Forces and Moments
Authors: Saxena A. , Kramer Steven N.
Published: February 2021

Compliant members in flexible link mechanisms undergo large deflections when subjected to external loads for which, traditional methods of deflection analysis do not apply Nonlinearities introduced by these large deflections make the system comprising such members difficult to solve Parametric deflection approximations are then deemed helpful in the analysis and synthesis of compliant mechanisms This is accomplished by seeking the pseudo-rigid-body model representation of the compliant mechanism A wealth of analysis and synthesis techniques available for rigid-body mechanisms thus become amenable to the design of compliant mechanisms In this paper, a pseudo-rigid-body model is developed and solved for the tip deflection of flexible beams for combined end loads with positive end moments A numerical integration technique using quadrature formulae has been employed to solve the nonlinear Bernoulli-Euler beam equation for the tip deflection Implementation of this scheme is relatively simpler than the elliptic integral formulation and provides nearly accurate results Results of the numerical integration scheme are compared with the beam finite element analysis An example for the synthesis of a compliant mechanism using the proposed model is also presented.
SPADES: Software for Synthesizing Spatial 4C Mechanisms
Authors: Larochelle Pierre M.
Published: February 2021

In this paper we present Spades, an interactive graphics based software package for SPAtial mechanism DESign. The program provides a platform for the synthesis of a mechanism that guides a body through either three or four prescribed positions in space.

The purpose of this work is to assemble the current spatial 4C synthesis theory into a software package that is useful for spatial mechanism design and research.
Completely Specified Displacements of a Rigid Body and Their Application in the Direct Kinematics of In-Parallel Mechanisms
Authors: Mavroidis Constantinos
Published: February 2021

In this paper we study the type of completely specified displacements of a rigid body where the distances of six points on the body, between their final and initial positions, have been specified. A method is presented to calculate the screws associated with these displacements. It is shown that there are 24 different screws at the most that will bring the rigid body from the initial to its final position to satisfy the six distances. If the six points are co-planar or symmetrical with respect to a plane then the number of screws reduces to 16. The method to calculate the screws associated with these completely specified displacements, is used to obtain a simple algebraic solution to the direct kinematics problem of a special type of in-parallel mechanisms: the mechanisms where the moving and the fixed platforms are the same.
Mobility in Metamorphic Mechanisms of Foldable/Erectable Kinds
Authors: Dai Jian S. , Jones John Rees
Published: February 2021

This paper looks at class of mechanisms that change structure when erected or folded. The class includes a variety of artefacts and decorative gifts and boxes comprised of flat card creased to enable the folding or unfolding of a structure. Such a structure admits kinematics study in keeping with theory of mechanisms when the creases are treated as hinges joining card and paper panels treated as links. New horizons have been brought up in the use and mechanised manufacture of mechanisms of this kind. Here typical types are described in terms of their fundamental parts and their equivalent mechanisms. Screw system theory is brought into the analysis of mechanisms of these kinds, particularly those containing multiple loops. Different geometry and system combinations are used for the study of mobility and kinematics making use of the result from the equivalent screw systems.
Catastrophe Analysis of Planar Three-Spring Systems
Authors: Yin J. P. , Marsh D. , Duffy J.
Published: February 2021

A special planar three-spring mechanism is proposed for contact force control. An energy function is defined to describe the behavior of this kind of mechanism. It can be used to perform the catastrophe analysis of this mechanism. The analysis result can be used as a design and control tool. By comparing the three-spring system and a two-spring system, we found the three-spring mechanism has better stability than the two-spring system. A three-spring mechanism which can be used to control a general contact force in a plane is also analyzed.
Study on Dimension Synthesis of Planar 4-Bar Linkages for Rigid-Body Guidance With Prescribed Timing
Authors: Xin Wu , Jinkui Chu , Weiqing Cao
Published: February 2021

A computer method is firstly proposed, which is used to do the dimension synthesis of planar 4-bar linkages for rigid-body guidance with Prescribed Timing (in short PT) by harmonic component’s database of the coupler’s rotation-angle function. The relationship between position function of rigid-body guidance with PT and coupler’s rotation-angle function of 4-bar linkage is analyzed. The key of the method is to solve the real dimension of linkage, coupler’s point position and installing dimensions of the linkage. Considering solving the problem, a harmonic component’s database of the coupler’s rotation-angle function including 20350 dimensional types, taking the crank-rocker linkage as an example, is established. So, it is possible to choose some linkages from the database to realize rigid-body guidance with PT by using fuzzy identification method quickly, and to approximately achieve “infinite positions” of dimensional synthesis for rigid-body guidance. An example is given to illustrate the efficiency and advantage of this method.
An Iterative Kinematic and Force Solution Method for Revolute Joints With Clearances
Authors: Biswas Arunava , Kinzel Gary L.
Published: February 2021

This paper outlines a procedure for modeling revolute joints with clearances and solving for the quasi-static forces in a mechanism with clearances in the joints. The results from the force analysis are used in an iterative fashion along with the position, velocity, and acceleration analysis to finally obtain the kinematic solution for the mechanism with clearances at the joints. The iterative procedure is general and essentially remains the same for other joint types. The situation for revolute joints is presented here. A general outline of the clearance joint model and the iterative procedure is given first, followed by the flowchart of the process and an example.
Singularity and Controllability Analysis of Parallel Manipulators
Authors: Choudhury Prasun , Ghosal Ashitava
Published: February 2021

This paper presents a study of kinematic and force singularities and their relationship to the controllability of planar and spatial parallel manipulators. Parallel manipulators are classified according to their degrees of freedom, number of output Cartesian variables used to describe their motion and the number of actuated joint inputs. The singularities in the workspace of a parallel manipulator are studied by considering the force transformation matrix which maps the forces and torques in joint space to output forces and torques in Cartesian space. The uncontrollable regions in the workspace of the parallel manipulator are obtained by deriving the equations of motion in terms of Cartesian variables and by using techniques from Lie Algebra. We show that when the number of actuated joint inputs is equal to the number of output Cartesian variables, and the force transformation matrix loses rank, the parallel manipulator is uncontrollable. For the case of manipulators where the number of joint inputs is less than the number of output Cartesian variables, if the constraint forces and torques (represented by the Lagrange multipliers) become infinite, the force transformation matrix loses rank. Finally, we show that the singular and uncontrollable regions in the workspace of a parallel manipulator can be reduced by adding redundant joint actuators and links. The results are illustrated with the help of numerical examples where we plot the singular and uncontrollable regions of parallel manipulators belonging to the above mentioned classes.
Kinetostatic Synthesis of Coupled Serial Chains
Authors: Krovi Venkat , Ananthasuresh G. K. , Kumar Vijay
Published: February 2021

Single Degree-of-freedom Coupled Serial Chain (SDCSC) mechanisms are a novel class of modular and compact mechanisms with single degree-of-freedom actuation and control. In this paper, the kinetostatic synthesis of SDCSC mechanisms is addressed. Using the principle of virtual work, the static force equilibrium equations are developed for two-link SDCSCs. These are combined with the previously developed kinematic loop-closure equations to solve the kinetostatic precision point synthesis problem. Since the ratios of the angular velocities at the joints are constants by virtue of cable-pulley coupling in SDCSCs, it possible to render the kinetostatic equations linear in terms of the mechanism parameters. As a result, the solution of the precision point synthesis problem of SDCSCs becomes simpler compared to that of the four-bar mechanism. In order to meet additional criteria such as minimizing the maximum torque required over the entire range of motion of the mechanism, an optimization problem is formulated. The free choices in the precision point synthesis are used as variables in the optimal synthesis problem. The paper also addresses how torsional springs at the joints can be utilized to reduce the required input torque in supporting a specified load at the end-effector. Numerical examples are presented to illustrate the precision point and the optimal synthesis of two-link SDCSC mechanism with and without torsional springs at the joints.
Combined Trajectory Planning and Parameter Identification of a Two-Link Rigid Manipulator
Authors: Fotouhi-C. Reza , Nikiforuk Peter N. , Szyszkowski Walerian
Published: February 2021

A combined trajectory planning problem and adaptive control problem for a two-link rigid manipulator is presented in this paper. The problem is divided into two parts: path planning for off-line processing, followed by on-line path tracking using an adaptive controller. The path planning is done at the joint level. The motion of the robot is specified by a sequence of knots (positions of the robot’s tip) in space Cartesian coordinates. These knots are then transformed into two sets of joint displacements, and piecewise cubic polynomials are used to fit these two sequences of joint displacements. The cubic spline function is used to construct a trajectory with the velocity and the acceleration as constraints. Linear scaling of the time variable is used to accommodate the velocity and acceleration constraints. A nonlinear scaling of the time variable is performed to fit the velocity to a pre-specified velocity profile. The adaptive scheme used takes full advantage of the known parameters of the manipulator while estimating the unknown parameters. In deriving the dynamic equations of motion, all of the physical parameters of the manipulator, including the distributed masses of the links, are taken into account. Some simulation results for the manipulator with unknown payload masses following a planned trajectory are presented.
Controlling conduction band alignment and carrier concentration in gallium-doped magnesium zinc oxide by reactive cosputtering
Authors: Yeung Gavin , Wolden Colin A.
Published: February 2021

Gallium-doped magnesium zinc oxide (GMZO) holds promise as a UV transparent conducting oxide with tunable bandgap and conductivity, though there has been relatively limited exploration of the broad compositional space available. Conductive GMZO films were deposited by reactive cosputtering at room temperature followed by annealing. The contributions of alloying and the Burstein–Moss effect to the optical bandgap were decoupled through comparisons of as-deposited and annealed films. Compositional analysis in conjunction with electrical characterization was used to quantify the activation of Ga doping in MZO. Combinatorial synthesis was used to explore the optoelectronic performance over a broad composition space. Reactive cosputtering can be used to tailor GMZO properties for optoelectronic applications over a wide range of bandgaps (3.3–4 eV) and resistivity (10−3–>100 Ω cm) through appropriate control of the Mg/Zn ratio and Ga content, respectively.
Formation of ideally ordered porous anodic zirconia by anodization of vacuum deposited Zr on molds
Authors: Kondo Toshiaki , Tamura Touko , Yanagishita Takashi , Masuda Hideki
Published: February 2021

We studied the formation of ideally ordered nanoporous zirconia by anodizing Zr having a texturing pattern. A texturing pattern was formed on a Zr surface by peeling off a sputtered zirconium film from a metal (Ni) mold having an ordered array of convexes. In contrast to texturing by nanoimprinting, the present texturing process never requires the pressing of a mold onto the Zr surface. During the anodization of Zr that has a texturing pattern on its surface, which is an ideally ordered array of concaves, each concave acted as a starting point of the formation of nanoholes. By the present process, porous anodic zirconia having an ideally ordered array of nanoholes was obtained. The interval between nanoholes in the porous anodic zirconia agreed with the texturing pattern.
Hydration and cooling in elite athletes: relationship with performance, body mass loss and body temperatures during the Doha 2019 IAAF World Athletics Championships
Authors: Racinais Sebastien , Ihsan Mohammed , Taylor Lee , Cardinale Marco , Adami Paolo Emilio , Alonso Juan Manuel , Bouscaren Nicolas , Buitrago Sebastian , Esh Chris J , Gomez-Ezeiza Josu , Garrandes Frederic , Havenith George , Labidi Mariem , Lange Gunter , Lloyd Alexander , Moussay Sebastien , Mtibaa Khouloud , Townsend Nathan , Wilson Mathew G , Bermon Stephane
Published: February 2021

Purpose

To characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions.

Methods

Marathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore(n=56) and Tsk(n=49; thermography) were measured.

Results

Most athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%–93% vs 67%–72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or mid-cooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%–2%). Pre-race Tcorewas lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore(pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tskwas correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (−2.8±1.5% vs −1.3±1.6%, p<0.001), although not associated with performance.

Conclusion

Most athletes’ hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tskwas related to performance and DNF, suggesting that Tskmodulation should be incorporated into pre-race strategies.
Food insecurity is associated with mental health problems among Canadian youth
Authors: Men Fei , Elgar Frank J. , Tarasuk Valerie
Published: February 2021

Background

Research has linked food insecurity to mental health problems, though little is known about this relationship among Canadian youth. We investigate the association between food insecurity severity and mental illnesses in a nationally representative youth sample.

Methods

We sampled 55 700 youth 12–24 years from recent cycles of Canadian Community Health Survey. Household food insecurity was measured using a standard 18-item questionnaire. We fitted Poisson regressions on self-rated mental health and diagnosed mood and anxiety disorders, controlling for sociodemographic confounders. Clinical assessments of emotional distress, major depression and suicidal ideation were examined in subsamples with available data. We stratified the sample by gender, age and survey cycle to test potential demographic heterogeneity.

Results

One in seven youth lived in marginal (5.30%), moderate (8.08%) or severe (1.44%) food insecurity. Results showed that food insecurity was associated with higher likelihood of every mental health problem examined. The association was graded, with more severe food insecurity linked to progressively worse mental health. Notably, marginal, moderate and severe food insecurity were associated with 1.77, 2.44 and 6.49 times higher risk of suicidal thoughts, respectively. The corresponding relative risk for mood disorders were 1.57, 2.00 and 2.89; those for anxiety disorders were 1.41, 1.65 and 2.58. Moderate food insecurity was more closely associated with mental health problems in 18–24 year olds than in 12–17 year olds.

Conclusions

Food insecurity severity was associated with poorer mental health among Canadian youth independent of household income and other socioeconomic differences. Targeted policy intervention alleviating food insecurity may improve youth mental health.
CMTM6 and PD-L1 coexpression is associated with an active immune microenvironment and a favorable prognosis in colorectal cancer
Authors: Peng Qi-Hua , Wang Chun-Hua , Chen Hong-Min , Zhang Rong-Xin , Pan Zhi-Zhong , Lu Zhen-Hai , Wang Gao-Yuan , Yue Xin , Huang Wenlin , Liu Ran-Yi
Published: February 2021

Background

CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6), a programmed death-ligand 1 (PD-L1) regulator, is widely expressed in various tumors and regulates the immune microenvironment. However, its prognostic value remains controversial, and the roles of CMTM6 in colorectal cancer (CRC) are still unknown. In this study, we aimed to elaborate the expression patterns of CMTM6 and PD-L1 in CRC and investigate their relationship with the infiltration of T cells and the prognosis of patients with CRC.

Methods

Analysis of CMTM6 mRNA levels, gene ontology enrichment analysis and single-sample gene set enrichment analysis were performed in a The Cancer Genome Atlas colon cancer cohort. The expression of CMTM6 and PD-L1 and the infiltration of T cells in tumor tissues from our cohort containing 156 patients with CRC receiving adjuvant chemotherapy and 77 patients with CRC without chemotherapy were examined by immunohistochemistry assay.

Results

CMTM6 expression was upregulated in CRC compared with normal colon tissues, and CMTM6 levels were lower in advanced tumors than in early-stage tumors. High expression of CMTM6 correlated with lower pT stage and more CD4+/CD8+tumor-infiltrating lymphocytes (TILs) and predicted a favorable prognosis in CRC. PD-L1 was expressed in CRC tissues at a low level, and PD-L1 positivity in tumor stroma (PD-L1(TS)), but not PD-L1 positivity in cancer cells (PD-L1(CC)), was associated with an increased density of CD4+TILs and a favorable prognosis. The coexpression status of CMTM6 and PD-L1(TS) divided patients with CRC into three groups with low, moderate and high risks of progression and death, and patients with CMTM6High/PD-L1(TS)+status had the longest survival. Moreover, the prognostic value of CMTM6/PD-L1 expression was more significant in patients with CRC treated with adjuvant chemotherapy than in those not treated with chemotherapy.

Conclusion

CMTM6 has a critical impact on the immune microenvironment and can be used as an independent prognostic factor for CRC. The coexpression status of CMTM6 and PD-L1 can be used as a new classification to stratify the risk of progression and death for patients with CRC, especially for patients receiving adjuvant chemotherapy. These findings may provide insights into improving responses to immunotherapy-included comprehensive treatment for CRC in the future.
Adrenal gland as a sanctuary site for immunotherapy in patients with microsatellite instability-high metastatic colorectal cancer
Authors: Cohen Romain , Jonchère Vincent , De La Fouchardière Christelle , Ratovomanana Toky , Letourneur Quentin , Ayadi Mira , Armenoult Lucile , Buisson Adrien , Sarabi Matthieu , Pellat Anna , Colle Raphael , Paye Francois , Meeus Pierre , Svrcek Magali , Duval Alex , Andre Thierry
Published: February 2021

Metastatic colorectal cancers (mCRC) harboring microsatellite instability (MSI) are sensitive to immune checkpoint inhibitors (ICIs), but the mechanisms of resistance to ICIs remain unclear. Dissociated responses in patients with ICI-treated cancer suggest that certain organs may serve as sanctuary sites due to the tumor microenvironment. This case series describes five patients with ICI-treated MSI mCRC with disease progression limited to the adrenal glands. At ICI initiation, three patients were free of metastasis in the adrenal glands. Four patients experienced objective response per RECIST (Response Evaluation Criteria in Solid Tumors) while treated with ICI. ICI treatment was discontinued due to progressive disease limited to the adrenal glands (n=3) or toxicity (n=2). The time between ICI initiation and progression in the adrenal glands ranged from 11 to 39 months. Adrenalectomy (n=3) and stereotactic body radiation therapy (n=2) were performed. At the last follow-up, all patients were alive and progression free. Molecular analyses were performed in one patient. A significant impairment of the antigen presentation pathway was observed in the ICI-resistant lesion of the adrenal gland, which could be explained by the presence of glucocorticoids in the adrenal gland microenvironment. We also detected an overexpression of TSC22D3, a glucocorticoid-target gene that functions as a mediator of anti-inflammation and immunosuppression. This case series suggests that the adrenal glands may be the sanctuary sites for ICI-treated MSI mCRC through the glucocorticoid-induced impairment of the antigen presentation machinery.
Systematic review and meta-analysis of anakinra, sarilumab, siltuximab and tocilizumab for COVID-19
Authors: Khan Fasihul A , Stewart Iain , Fabbri Laura , Moss Samuel , Robinson Karen , Smyth Alan Robert , Jenkins Gisli
Published: February 2021

Background

There is accumulating evidence for an overly activated immune response in severe COVID-19, with several studies exploring the therapeutic role of immunomodulation. Through systematic review and meta-analysis, we assess the effectiveness of specific interleukin inhibitors for the treatment of COVID-19.

Methods

Electronic databases were searched on 7 January 2021 to identify studies of immunomodulatory agents (anakinra, sarilumab, siltuximab and tocilizumab) for the treatment of COVID-19. The primary outcomes were severity on an Ordinal Scale measured at day 15 from intervention and days to hospital discharge. Key secondary endpoints included overall mortality.

Results

71 studies totalling 22 058 patients were included, 6 were randomised trials. Most studies explored outcomes in patients who received tocilizumab (60/71). In prospective studies, tocilizumab was associated with improved unadjusted survival (risk ratio 0.83, 95% CI 0.72 to 0.96, I
2
=0.0%), but conclusive benefit was not demonstrated for other outcomes. In retrospective studies, tocilizumab was associated with less severe outcomes on an Ordinal Scale (generalised OR 1.34, 95% CI 1.10 to 1.64, I
2
=98%) and adjusted mortality risk (HR 0.52, 95% CI 0.41 to 0.66, I
2
=76.6%). The mean difference in duration of hospitalisation was 0.36 days (95% CI −0.07 to 0.80, I
2
=93.8%). There was substantial heterogeneity in retrospective studies, and estimates should be interpreted cautiously. Other immunomodulatory agents showed similar effects to tocilizumab, but insufficient data precluded meta-analysis by agent.

Conclusion

Tocilizumab was associated with a lower relative risk of mortality in prospective studies, but effects were inconclusive for other outcomes. Current evidence for the efficacy of anakinra, siltuximab or sarilumab in COVID-19 is insufficient, with further studies urgently needed for conclusive findings.

PROSPERO registration number

CRD42020176375.
Tobacco retail licencing systems in Europe
Authors: Kuipers Mirte A G , Nuyts Paulien A W , Willemsen Marc C , Kunst Anton E
Published: February 2021

Tobacco retailer licencing has been recommended as an effective tobacco control strategy. In most European countries, however, retailers do not need a licence to sell tobacco products. We aimed to stimulate a discussion on the potential for tobacco retail licencing in Europe by describing (1) potential public health benefits, (2) licencing methods and (3) barriers and success factors in adoption of licencing systems. There is limited scientific evidence, but tobacco retail licencing may reduce smoking in three ways: (1) improved enforcement of and compliance to existing point-of-sale tobacco control policies (eg, minimum age of sale), (2) a reduction in the number and/or density of tobacco retail outlets and (3) denormalisation of tobacco. Licencing systems may take diverse forms. Systems may make licences expensive, and set criteria for purchasing a licence and retaining the licence after first purchase. In Europe, licencing systems have been implemented in Finland, Hungary, France, Italy and Spain. Licencing in Finland and Hungary was adopted for public health reasons; in Finland, with strong public support. In France, Italy and Spain, tobacco sales were state-monopolised, driven by economic motives. The cases of Norway and Scotland show that adoption of retail licencing may fail when political support is insufficient and tobacco retailers organise opposition with support from the tobacco industry. In conclusion, tobacco retailer licencing is a promising method to contribute to tobacco control efforts. Placing tobacco retailer licencing in a child protection framework may help generate the strong political and public support needed to effectively adopt licencing systems.
A Conforming A-FEM for Modeling Arbitrary Crack Propagation and Branching in Solids
Authors: Ma Zhaoyang , Xu Yunwei , Li Shu , Yang Qingda , Guo Xingming , Su Xianyue
Published: February 2021

In this paper, an improved conforming AFEM (C-AFEM) for efficient modeling of arbitrary crack propagation and branching is proposed and validated. An explicit formulation for branching cracks has been derived within the C-AFEM framework. The conjugate gradient method is integrated into the C-AFEM formulation to solve the local problem that consists of all elements traversed by single or multiple cracks. Multiple numerical evidences show that this new approach can substantially improve the modeling efficiency. The solution accuracy and numerical robustness are also significantly improved.
KylinX
Authors: Zhang Yiming , Zhang Chengfei , Wang Yaozheng , Yu Kai , Xue Guangtao , Crowcroft Jon
Published: February 2021

Unikernel specializes a minimalistic LibOS and a target application into a standalone single-purpose virtual machine (VM) running on a hypervisor, which is referred to as (virtual)
appliance
. Compared to traditional VMs, Unikernel appliances have smaller memory footprint and lower overhead while guaranteeing the same level of isolation. On the downside, Unikernel strips off the
process
abstraction from its monolithic appliance and thus sacrifices flexibility, efficiency, and applicability.

In this article, we examine whether there is a balance embracing the best of both Unikernel appliances (strong isolation) and processes (high flexibility/efficiency). We present KylinX, a dynamic library operating system for simplified and efficient cloud virtualization by providing the pVM (process-like VM) abstraction. A pVM takes the hypervisor as an OS and the Unikernel appliance as a process allowing both page-level and library-level dynamic mapping. At the page level, KylinX supports pVM fork plus a set of API for inter-pVM communication (IpC, which is compatible with conventional UNIX IPC). At the library level, KylinX supports shared libraries to be linked to a Unikernel appliance at runtime. KylinX enforces mapping restrictions against potential threats. We implement a prototype of KylinX by modifying MiniOS and Xen tools. Extensive experimental results show that KylinX achieves similar performance both in micro benchmarks (fork, IpC, library update, etc.) and in applications (Redis, web server, and DNS server) compared to conventional processes, while retaining the strong isolation benefit of VMs/Unikernels.
Adaptable and Multifunctional Ion-Conducting Aquaporins
Authors: Tyerman Stephen D. , McGaughey Samantha A. , Qiu Jiaen , Yool Andrea J. , Byrt Caitlin S.
Published: February 2021

Aquaporins function as water and neutral solute channels, signaling hubs, disease virulence factors, and metabolon components. We consider plant aquaporins that transport ions compared to some animal counterparts. These are candidates for important, as yet unidentified, cation and anion channels in plasma, tonoplast, and symbiotic membranes. For those individual isoforms that transport ions, water, and gases, the permeability spans 12 orders of magnitude. This requires tight regulation of selectivity via protein interactions and posttranslational modifications. A phosphorylation-dependent switch between ion and water permeation in AtPIP2;1 might be explained by coupling between the gates of the four monomer water channels and the central pore of the tetramer. We consider the potential for coupling between ion and water fluxes that could form the basis of an electroosmotic transducer. A grand challenge in understanding the roles of ion transporting aquaporins is their multifunctional modes that are dependent on location, stress, time, and development.
Modeling of Lithium Nucleation and Plating Kinetics Under Fast Charge Conditions
Authors: Vikrant K. S. N. , Allu Srikanth
Published: February 2021

The onset of lithium nucleation and subsequent plating on the graphite particles is a challenging problem in the design of fast charging batteries. A variational phase field formulation has been developed to initiate the nucleation of lithium particles based on the local plating overpotential conditions and allowing to predict the lithium plating under fast charge conditions. The model demonstrates that (1) at small charging current density, there is no nucleation and plating of metallic lithium, and no effect on the intercalation kinetics; (2) at intermediate charging current densities, initially a stagnated growth from isolated lithium nuclei is observed followed by a continuous growth of metallic lithium; (3) at large charging current densities, a continuous growth of metallic lithium resulting from coalescence of small nuclei into large nuclei decreases the excess interfacial energy, which in turn slows down the intercalation kinetics. The formulation sets the stage for predicting and evaluating the influence of various electrolyte compositions, graphite particle morphologies and electrode loadings on the nucleation and plating dynamics under fast charge conditions.