bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Impact Behavior of a Material With a Yield Point
Authors: White Merit P.
Published: April 2021

An analysis of longitudinal impact tests that were made by Drs. D. S. Clark and P. E. Duwez at the California Institute of Technology on an iron and a steel with definite yield points is described. From this analysis is deduced the probable nature of the dynamic stress-strain relations for such materials. These appear to differ greatly from the static stress-strain relations, unlike the case for materials without yield points. As pointed out by Duwez and Clark, the upper yield stress for undeformed material is several times as great under impact as the static yield stress. The present analysis indicates that under impact, the material with a definite yield point is made harder at a given deformation, and ruptures at a higher (engineering) stress and smaller strain than when loaded statically. The critical impact velocity, defined as that at which nearly instantaneous failure occurs in tension, is discussed, and the factors upon which it depends are given.
Thermal Stresses in a Rectangular Plate Clamped Along an Edge
Authors: Aleck B. J.
Published: April 2021

An approximate solution has been obtained for the stresses induced by a uniform change in temperature of a thin rectangular plate, clamped along an edge. The solution has been carried to completion for plates whose clamped edge is long, i.e., more than 5 times the length of the perpendicular free edge. The solution for smaller ratios of clamped to perpendicular lengths is expressed in terms of six determined functions whose coefficients are to be evaluated by satisfying two boundary conditions. The thermal-stress problem is first converted to one of specified boundary tractions. The normal stress, σx, parallel to the clamped edge is assumed of the form σx = f1 (x) + y f2(x) + y2f3(x), where fi(x) are as yet undetermined functions, and where y is the co-ordinate at right angles to the clamped edge. Using the equations of equilibrium and the boundary conditions, τxy and σy are expressed in terms of powers of y and the derivatives of fi(x). The integral representing the strain energy is then expressed in terms of the expressions for σx, σy, and τxy. In accordance with the principle of least work, the integral representing the strain energy is minimized, using the calculus of variations. The resulting simultaneous differential equations for fi(x) are solved as a linear combination of twelve functions (six of which drop out, by symmetry). Given f1(x), then f2(x) and f3(x) are determinate by virtue of the simultaneous equations. The six coefficients in the expression for f1 are evaluated by satisfying the boundary conditions along the free edges. The maximum normal stress concentration, over 10, occurs at the junction of the free and clamped edges.
Slow-Motion Pictures of Impact Tests by Means of Photoelasticity
Authors: Foeppl Ludwig
Published: April 2021

The experiments described in this paper were carried out in investigating the distribution of stresses and their variation with time in a test bar subject to bending stresses resulting from an impact. While a series of tests has been made, only two of them will be dealt with in detail. In the first test the impact is of moderate intensity, so that the response is entirely elastic. The test results will be compared with a theoretical treatise by St. Venant and Flamant published in 1889. In the second test the impact is strong enough to break the test bar.
Supersonic Diffusers for Wind Tunnels
Authors: Neumann E. P. , Lustwerk F.
Published: April 2021

An investigation of supersonic diffusers was conducted for conditions wherein a boundary layer was present at the diffuser entrance. The pressure rise obtained from a shock in a constant-area tube was measured, and the measurements compared with values computed from a simple one-dimensional analysis. For the range of Mach numbers covered (1.8 to 4.2), separation of the stream from the tube wall was always induced by the shock. The length of the separated region was from 8 to 12 tube diameters. The results of the tests on shocks in a constant-area tube were utilized in the design of several types of diffusers for which test data are reported at Mach numbers ranging from 2 to 3. The most efficient diffuser tested consisted of a contraction to a minimum starting area followed by a constant-area tube approximately 10 diam long. The tube was in turn followed by a subsonic diffuser. Only diffusers of constant geometry were considered.
Note on the Bending of Circular Plates of Variable Thickness
Authors: Conway H. D.
Published: April 2021

In a recent paper a solution was given to the problem of a symmetrically loaded circular plate with a central hole, the thickness of the plate at any section being proportional to the distance of the section from the center of the plate. A very simple solution can be obtained for another variation of thickness of which the foregoing is a special case.
The Dynamics of Cavitation Bubbles
Authors: Plesset M. S.
Published: April 2021

Three regimes of liquid flow over a body are defined, namely: (a) noncavitating flow; (b) cavitating flow with a relatively small number of cavitation bubbles in the field of flow; and (c) cavitating flow with a single large cavity about the body. The assumption is made that, for the second regime of flow, the pressure coefficient in the flow field is no different from that in the noncavitating flow. On this basis, the equation of motion for the growth and collapse of a cavitation bubble containing vapor is derived and applied to experimental observations on such bubbles. The limitations of this equation of motion are pointed out, and include the effect of the finite rate of evaporation and condensation, and compressibility of vapor and liquid. A brief discussion of the role of “nuclei” in the liquid in the rate of formation of cavitation bubbles is also given.
General Features of Plastic-Elastic Problems as Exemplified by Some Particular Solutions
Authors: Hill Rodney
Published: April 2021

New complete solutions based upon the Reuss equations are obtained for various plastic-elastic problems. These include the expansion of a spherical shell and of a cylindrical hole in an infinite medium. The solutions are used to exemplify certain features common to all plastic-elastic problems, with a view to introducing valid approximations in more complex cases.
A Matrix Method of Calculating Propeller-Blade Moments and Deflections
Authors: Plunkett R.
Published: April 2021

A new method is demonstrated for finding the bending moments and deflections of a twisted cantilever beam due to both transverse and axial loads. The actual physical system is approximated by a lumped or discrete system which is handled by matrix methods. It is shown that good accuracy may be expected even with slide-rule computation, since the method corresponds to a set of successive numerical integrations. The setup is particularly adapted to investigating the effects of changing the initial offset and of different rotating speeds of a propeller or turbine blade. In addition, a procedure is demonstrated for the application of a successive approximation method, analogous to a Stodola solution, to a problem which would otherwise show oscillating divergent results.
Impact of a Mass on a Column
Authors: Hoppmann W. H.
Published: April 2021

In this paper a study is made of the problem of the transverse impact of a mass on a column with simply supported ends. Consideration is also given to the case in which the column has elastic support throughout its length. Formulas are obtained for the deflections and strains. Numerical examples illustrating the theory are worked out in detail.
The Effect of an Axial Force on the Vibration of Hinged Bars
Authors: Woinowsky-Krieger S.
Published: April 2021

It can be shown that the vibration of an extensible bar, carrying no transverse load and having the ends fixed at the supports, causes an axial tensile force with a period equal to the half-period of the vibration of the bar. This force modifies the process of the vibration to a nonlinear one and produces an increase of the frequency of vibration according to the increase of the amplitude.
Graphical, Mechanical, and Electrical Aids for Compressible Fluid Flow
Authors: Poritsky H. , Sells B. E. , Danforth C. E.
Published: April 2021

Graphical, mechanical, and electrical methods of studying two-dimensional and axially symmetrical irrotational flow of nonviscous compressible fluids are described and examples are given of problems solved by these methods. Rules for the construction of compressible flux plots using wires, beads, and a suitable device for obtaining the desired length-width ratios of the rectangles are derived, and the apparatus used is described. An analogy is described by means of which these problems can be solved by the use of a d-c resistance board, employing variable resistances which are adjusted to conform to the derived relations. Designers and aerodynamicists in need of solution for problems for which no analytical solutions are available can use the methods described in this paper to obtain the required solutions.
Deflections and Moments Due to a Concentrated Load on a Cantilever Plate of Infinite Length
Authors: Jaramillo T. J.
Published: April 2021

This paper contains an exact solution in terms of improper integrals for the deflections and moments due to a transverse concentrated load acting at an arbitrary point of an infinitely long cantilever plate of constant width and thickness. The solution is transformed into series form by means of contour integration, and is illustrated by numerical examples. In particular, comparisons are made with the known solution (1) for the special case where the load is applied at the free edge of the plate. The results obtained are of practical significance in connection with the design of certain types of monorail cranes.
Acceleration of the Instant Center
Authors: Carter W. J.
Published: April 2021

The acceleration of the members of a mechanism having a “floating link,” such as that in Fig. 2, are not obtainable by the method of relative accelerations. Beskin has given a solution for this problem which involves the determination of the center of trajectory of points on a connecting link. The method presented in this paper makes use of the acceleration of the instant center of velocity, the acceleration of which is dependent only on the velocity of the linkage elements. The method developed may also be used to obtain the accelerations for linkages which normally require the use of Coriolis’ law.
Atomization of Liquids by Means of a Rotating Cup
Authors: Hinze J. O. , Milborn H.
Published: April 2021

Liquid, supplied through a stationary tube to the inner part of a rotating cup widening toward a brim, flows viscously in a thin layer toward this brim and is then flung off, all by centrifugal action. The flow within this layer and the disintegration phenomena occurring beyond the brim have been studied, experimentally as well as theoretically. A formula has been derived for the thickness and for the radial velocity of the liquid layer within the cup, which proved to agree reasonably well with experimental results. Three essentially different types of disintegration may take place around and beyond the edge of the cup designated, respectively, by: (a) the state of direct drop formation; (b) the state of ligament formation; and (c) the state of film formation. Which one of these is realized depends upon working conditions. Transition from state (a) into (b), or of state (b) into state (c) is promoted by an increased quantity of supply, an increased angular speed, a decreased diameter of the cup, an increased density, an increased viscosity, and a decreased surface tension of the liquid. The experimental results have been expressed in relationships between relevant dimensionless groups. For the state of ligament formation a semiempirical relationship has been derived between the number of ligaments and dimensionless groups determining the working conditions of the cup. Results of drop-size measurements made for the state of ligament formation as well as for the state of film formation show that atomization by mere rotation of the cup is much more uniform than commonly achieved with pressure atomizers.
Gaskets and Bolted Joints
Authors: Roberts Irving
Published: April 2021

This paper consists of a study of the loading requirements of gaskets in bolted joints, with the object of developing a rational basis for design of such joints. Starting with an analysis of gasket conditions for tightness, the gasket factor m is defined, and its variation with initial gasket stress and gasket width is predicted. These trends are confirmed by a survey of the available literature data.

In a bolted joint, gasket stress becomes a function of the elastic constants of the system. Equations are derived to predict gasket and bolt stresses resulting from application of internal fluid pressure, and typical elastic recovery curves for an asbestos gasket are presented. Consideration is given to the effect of gasket creep in a bolted joint, and to the problem of distribution of bolt load, for which an approximate theory is derived.

On this basis, defects in the ASME Code are pointed out, and a tentative new design procedure is proposed. Finally, a summary of data which should be obtained for use with the new design procedure is given.
Longitudinal and Torsional Impact in a Uniform Bar With a Rigid Body at One End
Authors: Burr A. H.
Published: April 2021

A uniform bar carrying a rigid body at one end is analyzed for those cases where its other end is struck by a rigid body, and struck by a bar and body, also for the case of sudden application of force at either end. Recurrence formulas are derived in nondimensional form and applied to determine in a finite number of terms the stress equations for striking impact and for a constant-force impact. Some useful theorems and simplifications, applicable to other problems of this nature, are indicated. For striking impact by a rigid body, charts show the time-variation of stress and the maximum stress for a range of physical values of the bar and bodies. Application to the design of bars, helical springs, and shafts is discussed.
Approximate Solutions of Problems of Plane Plastic Flow
Authors: Hodge P. G.
Published: April 2021

A method of approximating the stress and velocity fields in problems of plane plastic flow is presented. A general procedure for finding the deformed pattern of an originally square grid is devised and applied to two examples. The results are compared with known continuous solutions and with experiments.
The Calendering of Plastic Materials
Authors: Gaskell R. E.
Published: April 2021

Many industries, notably the paper, linoleum, rubber, and steel industries, use a rolling process to form or otherwise treat sheets of these various materials. To most engineers, perhaps, the term “rolling” brings to mind only the rolling of steel or aluminum—solids with definite yield points. Several mathematical studies of the rolling of such materials have already been made. In those studies, any shear stress beyond the yield stress is neglected. The plastic materials handled by other industries, however, do not often have the definite yield point of steel, or, after yielding takes place, they may behave more like liquids of very high and usually variable viscosity. Shear stress beyond the yield point, due to viscosity, cannot therefore be neglected. Consequently, a different approach must be made if a mathematical description of the process is to be formulated. Such an approach is made in this paper.
Matrix Solution for the Vibration of Nonuniform Beams
Authors: Thomson W. T.
Published: April 2021

A matrix method for the determination of natural frequencies of any nonuniform beam is presented. It accomplishes the same task as that of Myklestad’s tabular method with the added advantage of simplicity of formulation. Included is a procedure for the case where the nonuniform beam is represented by a series of uniform sections.
On the General Theory of Thin Shells
Authors: Osgood W. R. , Joseph J. A.
Published: April 2021

In the general theory of shells expressions are obtained for the changes of curvature and the twist, and revisions are introduced in the equations of equilibrium.
The Theory of Spring-Loaded Valves for Reciprocating Compressors
Authors: Costagliola Michael
Published: April 2021

The inlet and discharge processes of a reciprocating compressor equipped with spring-loaded valves of the automatic type have been analyzed to determine the effects of the main design variables on performance. The most important criterion is found to be a parameter involving effective flow area through the valves and piston speed. Valve dynamics is a secondary consideration. For optimum valve dynamics, the valve would have no weight and a very small spring constant, giving an infinite natural frequency of the valve system. If certain valve characteristics are known (or measured by static-flow test), the performance of a compressor using these valves can be predicted with fair accuracy.
A MEMS-Based Drug Delivery Device With Integrated Microneedle Array—Design and Simulation
Authors: Meshkinfam Farshid , Rizvi Ghus
Published: April 2021

One of the most effective treatments for type 1 and 2 diabetes is the administration of Insulin. Single needle mechanical insulin pumps are heavy and painful. Microneedle-based MEMS drug delivery devices can be an excellent solution for insulin dosing. The stackable structure provides minimum dimensions and the final product can be in the form of a patch that can be applied to any flat area of human skin. The use of microneedle array provides a safe, painless, and robust injection application. The design of positive volumetric insulin pump is a Multiphysics problem where the volumetric changes of the main pump chamber and the pumped fluid are directly coupled. We use a Multiphysics simulation system to investigate the performance of a MEMS-based insulin micropump with a piezoelectric actuator pumping a viscous Newtonian fluid. The model captures the accumulated out-flow, the netflow, or flow fluctuations based on deflection of piezoelectric diaphragm actuator. Different input voltages and different excitation frequencies cause movement of piezoelectric actuator, which moves the diaphragm disk in positive–negative directions thereby inducing discharge pressures at the microneedle array. In this study, we address various aspects of design and simulation of a MEMS-based piezoelectric insulin micropump including polydimethylsiloxane microvalves and microneedle array. We investigate the micropump performance at human skin interfacial pressure to match minimum to maximum delivery targets/requirements for total range of diabetic patient's expected operating parameters. comsolmultiphysics is used for this study.
Design of a Compact Magnetically Levitated Blower for Space Applications
Authors: Hawkins Larry , Filatov Alexei , Khatri Rasish , DellaCorte Chris , Howard S. Adam
Published: April 2021

NASA is leading the design and development of a next-generation CO2 removal system, the four bed carbon dioxide scrubber (4BCO2), and intends to use the International Space Station (ISS) as its testbed. A key component of the system is the blower that provides the airflow through the CO2 sorbent beds. To improve performance and reliability, magnetic levitation (magnetic bearings) will be used in lieu of more conventional bearings (e.g., ball bearings or air bearings) to improve resistance to contaminants and enable extensibility with regards to blower speed, pressure rise and mass flow rate. The blower will pull air from the ISS through an adsorbing desiccant bed and push it through a CO2 sorbent bed and desorbing desiccant bed. The 4BCO2 blower features an overhung permanent magnet motor, a centrally located five-axis, active magnetic bearing system, backup bearings, and an overhung centrifugal impeller in a very compact package. Magnetic bearings are a natural choice for this application due to low power consumption, low transmitted vibration and oil free operation. This article describes the design considerations and design selections for the blower system with a focus on the magnetic bearings. Magnetic FEA of the actuator/sensor system, rotordynamics/controls analysis, and backup bearing drop simulations are discussed in detail. It is expected that the successful implementation of magnetic bearings for this space application will encourage the more widespread adoption in other space applications (e.g., fluid pumps, reaction wheels) that challenge conventional bearing technologies.
Safety Method for the Pre-conceptual Phase of Sodium-cooled Fast Reactors
Authors: Ehster Sophie , Ammirabile Luca , Bubelis Evaldas , Carluec Bernard , Droin Jean-Baptiste , Girardi Enrico
Published: April 2021

The ESFR-SMART European project (Contract number: 754501) focuses on the development of innovative safety design options for future Sodium-cooled Fast Reactors (SFRs). The goal of this paper is to show how the Objective Provision Tree (OPT) method, which is part of the Integrated Safety Analysis Methodology (ISAM) developed by Generation IV Forum (GIF), can help in defining safety guidelines for the definition and the study of ESFR-SMART innovative design options. The OPT method provides a view of the implementation of main safety functions in accordance with defence-in-depth principle and has been adapted to ESFR-SMART needs. Guidance for a consistent and homogeneous application has been developed. The method is applied to each safety function with a specific adaptation for the confinement function. Beyond the allocation of the main equipment ensuring the safety functions to the different levels of defence-in-depth, the adapted method proposes a systematic identification of the mechanisms likely to degrade them. Then, safety features to cope with these mechanisms are investigated as well as the potential common cause failures of main equipment belonging to different levels of defence-in-depth. This adapted method allows to study and then to improve the independence between the levels of defence-in-depth as required for future reactors in Europe by Western European Nuclear Regulators' Association (WENRA). The paper provides the outline of guidance for OPT method adaptation to ESFR-SMART project needs, examples of application and main outcomes of the use of the method.
Evaluation of Sodium Boiling Models Using KNS-37 Loss of Flow Experiments
Authors: Perez-Martin Sara , Anderhuber Marine , Laborde Laurent , Girault Nathalie , Lombardo Calogera , Ammirabile Luca , Mikityuk Konstantin , Mimouni Stephane , Péniguel Christophe , Pfrang Werner
Published: April 2021

The computational codes used in the evaluation of the European sodium fast reactor—safety measures assessment and research tools(ESFR-SMART) reactor performance and specifically their sodium boiling models are assessed using two KNS-37 loss of flow (LOF) experiments, i.e., L22 and L29 tests, where boiling onset and two-phase flow regime up to dry-out occurred. The well-equipped KNS-37 experimental facility provided very valuable information for understanding the physical phenomena occurring in a 37-pin subassembly under LOF conditions, as well as experimental data to be used for computational tools validation. NATOF-2D, SAS-SFR, TRACE, ASTEC-Na, CATHARE-2, CATHARE-3, and NEPTUNE_CFD codes have been used in this exercise in order to compare the various boiling models and conclude on the advantages and limitations of them based on the comparison against the experimental data. Beyond boiling onset, the various sodium two-phase flow approaches determine the ability of the code to correctly represent the rewetting and voiding phases as well as cladding dry-out onset. A simulation performed by a computational fluid dynamics (CFD) approach (NEPTUNE_CFD code) taking into account liquid–vapor interfaces by an interface-tracking method is also shown and compared with the others approaches. Conclusions on each code performance are presented where the improvements needed to solve the issues encountered are included. This paper provides a first step in the process to investigate the required evaluation of the sodium two-phase flow models able to assess the safety of new SFR core designs (e.g., low void cores) under accidental conditions such as unprotected loss of flow (ULOF) transients.
Nonplanar metasurface for perfect absorption of sound waves
Authors: Kim Jiwan , Jeon Wonju
Published: April 2021

We propose a sound-absorbing nonplanar metasurface by considering locally different incidence angles along the metasurface. Perfect sound absorption is realized with the aid of hybrid resonance between two different subwavelength Helmhwoltz resonators comprising a unit cell. We theoretically investigate the effect of incidence angles on the sound absorption of the unit cells, and present a design method of the nonplanar metasurface that achieves perfect absorption by considering locally different incidence angles along the metasurface. The perfect absorption of plane sound waves on nonplanar surfaces is numerically demonstrated at the target frequency of 1 kHz. The numerical results show that at least 99.8% of the incident wave energy is absorbed by the designed metasurfaces with a thickness of λ/24. A nonplanar metasurface is fabricated via three-dimensional printing, and perfect sound absorption is experimentally validated at the target frequency of 1 kHz. Furthermore, we design nonplanar metasurfaces that can perfectly absorb cylindrical sound waves when a line source is located near the metasurface. While previous sound-absorbing metasurfaces focused only on planar surfaces, the proposed method achieves perfect sound absorption on nonplanar surfaces, expanding the range of practical applications in various industrial areas.
Narrowband multi-source direction-of-arrival estimation in the spherical harmonic domain
Authors: Hafezi Sina , Moore Alastair H. , Naylor Patrick A.
Published: April 2021

A conventional approach to wideband multi-source (MS) direction-of-arrival (DOA) estimation is to perform single source (SS) DOA estimation in time-frequency (TF) bins for which a SS assumption is valid. Such methods use the W-disjoint orthogonality (WDO) assumption due to the speech sparseness. As the number of sources increases, the chance of violating the WDO assumption increases. As shown in the challenging scenarios with multiple simultaneously active sources over a short period of time masking each other, it is possible for a strongly masked source (due to inconsistency of activity or quietness) to be rarely dominant in a TF bin. SS-based DOA estimators fail in the detection or accurate localization of masked sources in such scenarios. Two analytical approaches are proposed for narrowband DOA estimation based on the MS assumption in a bin in the spherical harmonic domain. In the first approach, eigenvalue decomposition is used to decompose a MS scenario into multiple SS scenarios, and a SS-based analytical DOA estimation is performed on each. The second approach analytically estimates two DOAs per bin assuming the presence of two active sources per bin. The evaluation validates the improvement to double accuracy and robustness to sensor noise compared to the baseline methods.
Complex Regional Pain Syndrome Type I in a Female Division I Soccer Player: A Level 4 CASE Report
Authors: McAlear Gina E. , Popp Jennifer K.
Published: April 2021

An 18-year-old female, Division I soccer player was diagnosed with complex regional pain syndrome approximately 2 weeks after tarsal tunnel release surgery. Postsurgically, the patient reported a significant increase in neuropathic pain, swelling, paresthesia, skin temperature asymmetry, and allodynia of the plantar and dorsal aspects of the foot, which were initially attributed to other causes. The intense pain and delayed diagnosis led to a decline in mental health and suicide ideation. Once diagnosed with complex regional pain syndrome, an epidural was placed at L5/S1 with a continuous flow of lidocaine, resulting in functional restoration. The patient’s diagnosis and recovery were based on the collaborative efforts of the surgeon, sports medicine physician, pain management specialist, and athletic trainer. She returned to soccer participation with minimal symptoms. This case is unique because the symptoms of complex regional pain syndrome were attributed to other causes, resulting in a delayed diagnosis and appropriate treatment. This delay resulted in the patient threatening self-harm.
Resistance Training Affects Neuromuscular Fatigue But Not Efficiency in Elite Rowers
Authors: van den Bogaard Timo B. , Bastiaans Jabik-Jan , Hofmijster Mathijs J.
Published: April 2021

Purpose: To investigate how resistance training (RT) in a regular training program affects neuromuscular fatigue (NMF) and gross efficiency (EGROSS) in elite rowers. Methods: Twenty-six elite male rowers performed 4 RT sessions within 10 days. At baseline and after the first and fourth RT, EGROSS and NMF were established. From breathing gas, EGROSS was determined during submaximal rowing tests. Using a countermovement jump test, NMF was assessed by jump height, flight time, flight-to-contraction-time ratio, peak power, and time to peak power. Muscle soreness was assessed using a 10-cm-long visual analog scale. Results: No significant differences were found for EGROSS (P = .565, ω2 = .032). Muscle soreness (P = .00, ω2 = .500) and time to peak power (P = .08, ω2 = 0.238) were higher compared with baseline at all test moments. Flight-to-contraction-time ratio, jump height, and peak power after the fourth RT differed from baseline (P < .05, ω2 = .36, ω2 = .38, and ω2 = .31) and from results obtained after the first RT (P < .05, ω2 = .36, ω2 = .47, and ω2 = .22). Conclusions: RT in general does not influence EGROSS, but large individual differences (4.1%–14.8%) were observed. NMF is affected by RT, particularly after multiple sessions. During periods of intensified RT, imposed external load for low-intensity endurance training need not be altered, but rowers are recommended to abstain from intensive endurance training. Individual monitoring is strongly recommended.
The Inclusion of Sprints in Low-Intensity Sessions During the Transition Period of Elite Cyclists Improves Endurance Performance 6 Weeks Into the Subsequent Preparatory Period
Authors: Taylor Madison , Almquist Nicki , Rønnestad Bent , Tjønna Arnt Erik , Kristoffersen Morten , Spencer Matt , Sandbakk Øyvind , Skovereng Knut
Published: April 2021

Purpose: To investigate the effects of including repeated sprints in a weekly low-intensity (LIT) session during a 3-week transition period on cycling performance 6 weeks into the subsequent preparatory period (PREP) in elite cyclists. Methods: Eleven elite male cyclists (age = 22.0 [3.8] y, body mass = 73.0 [5.8] kg, height = 186 [7] cm, maximal oxygen uptake [VO2max] = 5469 [384] mL·min−1) reduced their training load by 64% and performed only LIT sessions (CON, n = 6) or included 3 sets of 3 × 30-second maximal sprints in a weekly LIT session (SPR, n = 5) during a 3-week transition period. There was no difference in the reduction in training load during the transition period between groups. Physiological and performance measures were compared between the end of the competitive period and 6 weeks into the PREP. Results: SPR demonstrated a 7.3% (7.2%) improvement in mean power output during a 20-minute all-out test at PREP, which was greater than CON (−1.3% [4.6%]) (P = .048). SPR had a corresponding 7.0% (3.6%) improvement in average VO2 during the 20-minute all-out test, which was larger than the 0.7% (6.0%) change in CON (P = .042). No change in VO2max, gross efficiency, or power output at blood lactate concentration of 4 mmol·L−1 from competitive period to PREP occurred in either group. Conclusion: Including sprints in a weekly LIT session during the transition period of elite cyclists provided a performance advantage 6 weeks into the subsequent PREP, which coincided with a higher performance VO2.
Leading by Example: Association Between Mother and Child Objectively Measured Physical Activity and Sedentary Behavior
Authors: Julius Brad R. , O’Shea Amy M.J. , Francis Shelby L. , Janz Kathleen F. , Laroche Helena
Published: April 2021

Purpose: The authors examined the relationship between mother and child activity. Methods: The authors compared moderate–vigorous physical activity (MVPA) and sedentary time of low-income mothers with obesity and their 6- to 12-year-old children on week (WD) and weekend (WE) days. A total of 196 mother–child pairs wore accelerometers simultaneously for a week. Mothers completed questionnaires. Spearman correlation and multivariate regression were used. Results: WE MVPA (accelerometry) was significantly correlated between mothers with children aged 6–7 (rs = .35) and daughters (rs = .27). Self-reported maternal PA time spent with one of their children was significantly correlated with the WE MVPA of all children (rs = .21) and children aged 8–10 (rs = .22) and with the WD MVPA of all children (rs = .15), children aged 8–10 (rs = .23), aged 11–12 (rs = .52), and daughters (rs = .37), and inversely correlated to the WD sedentary time of all children (rs = −.21), children aged 8–10 (rs = −.30), aged 11–12 (rs = −.34), daughters (rs = −.26), and sons (rs = −.22). In multivariate regression, significant associations were identified between reported child–mother PA time together and child MVPA and sedentary time (accelerometry). Conclusions: Mothers may influence the PA levels of their children with the strongest associations found in children aged 6–7 and daughters. Mother–child coparticipation in PA may lead to increased child MVPA and decreased sedentary behavior.
The neutralizing antibody, LY-CoV555, protects against SARS-CoV-2 infection in nonhuman primates
Authors: Jones Bryan E. , Brown-Augsburger Patricia L. , Corbett Kizzmekia S. , Westendorf Kathryn , Davies Julian , Cujec Thomas P. , Wiethoff Christopher M. , Blackbourne Jamie L. , Heinz Beverly A. , Foster Denisa , Higgs Richard E. , Balasubramaniam Deepa , Wang Lingshu , Zhang Yi , Yang Eun Sung , Bidshahri Roza , Kraft Lucas , Hwang Yuri , Žentelis Stefanie , Jepson Kevin R. , Goya Rodrigo , Smith Maia A. , Collins David W. , Hinshaw Samuel J. , Tycho Sean A. , Pellacani Davide , Xiang Ping , Muthuraman Krithika , Sobhanifar Solmaz , Piper Marissa H. , Triana Franz J. , Hendle Jorg , Pustilnik Anna , Adams Andrew C. , Berens Shawn J. , Baric Ralph S. , Martinez David R. , Cross Robert W. , Geisbert Thomas W. , Borisevich Viktoriya , Abiona Olubukola , Belli Hayley M. , de Vries Maren , Mohamed Adil , Dittmann Meike , Samanovic Marie I. , Mulligan Mark J. , Goldsmith Jory A. , Hsieh Ching-Lin , Johnson Nicole V. , Wrapp Daniel , McLellan Jason S. , Barnhart Bryan C. , Graham Barney S. , Mascola John R. , Hansen Carl L. , Falconer Ester
Published: April 2021

LY-CoV555, a SARS-CoV-2 spike protein–specific antibody, neutralizes SARS-CoV-2 and protects the airways of nonhuman primates against infection.
Identification of a Novel Ciprofloxacin Tolerance Gene,
aciT
, Which Contributes to Filamentation in Acinetobacter baumannii
Authors: Naidu Varsha , Shah Bhumika , Kamath Karthik S. , Chien Arthur , Nagy Stephanie , Pokhrel Alaska , Molloy Mark , Hassan Karl A. , Paulsen Ian T.
Published: April 2021

Fluoroquinolones are one of the most prescribed broad-spectrum antibiotics. However, their effectiveness is being compromised by high rates of resistance in clinically important organisms, including
Acinetobacter baumannii
.
Structural Glycoprotein E2 of Classical Swine Fever Virus Critically Interacts with Host Protein Torsin-1A during the Virus Infectious Cycle
Authors: Vuono E. A. , Ramirez-Medina E. , Velazquez-Salinas L. , Berggren K. , Rai A. , Pruitt S. , Espinoza N. , Gladue D. P. , Borca M. V.
Published: April 2021

Structural glycoprotein E2 is an important structural component of the CSFV particle. E2 is involved in several virus functions, particularly virus-host interactions.
Oral Probiotic Vaccine Expressing Koi Herpesvirus (KHV) ORF81 Protein Delivered by Chitosan-Alginate Capsules Is a Promising Strategy for Mass Oral Vaccination of Carps against KHV Infection
Authors: Huang Xinning , Ma Yingying , Wang Yixin , Niu Chao , Liu Zhongmei , Yao Xin , Jiang Xiaoxia , Pan Ronghui , Jia Shuo , Li Dandan , Guan Xueting , Wang Li , Xu Yigang
Published: April 2021

An oral probiotic vaccine, pYG-KHV-ORF81/LR CIQ249, encapsulated by chitosan-alginate capsules as an oral delivery system was developed for koi carp against koi herpesvirus (KHV) infection. This encapsulated probiotic vaccine can be protected from various digestive environments and maintain effectively high viability, showing a good tolerance to digestive environments.
Deubiquitinating Enzyme USP21 Inhibits HIV-1 Replication by Downregulating Tat Expression
Authors: Gao Wenying , Li Guangquan , Zhao Simin , Wang Hong , Huan Chen , Zheng Baisong , Jiang Chunlai , Zhang Wenyan
Published: April 2021

Ubiquitination plays an essential role in viral infection. Deubiquitinating enzymes (DUBs) reverse ubiquitination by cleaving ubiquitins from target proteins, thereby affecting viral infection.
Gammaherpesvirus Usurps Host IL-17 Signaling To Support the Establishment of Chronic Infection
Authors: Jondle C. N. , Johnson K. E. , Aurubin C. , Sylvester P. , Xin G. , Cui W. , Huppler A. R. , Tarakanova V. L.
Published: April 2021

Gammaherpesviruses establish lifelong infections in a majority of humans and are associated with B cell lymphomas. IL-17A is a host cytokine that plays a well-established role in the clearance of bacterial and fungal infections; however, the role of IL-17A in viral infections is poorly understood.
Class A Penicillin-Binding Protein-Mediated Cell Wall Synthesis Promotes Structural Integrity during Peptidoglycan Endopeptidase Insufficiency in Vibrio cholerae
Authors: Murphy Shannon G. , Murtha Andrew N. , Zhao Ziyi , Alvarez Laura , Diebold Peter , Shin Jung-Ho , VanNieuwenhze Michael S. , Cava Felipe , Dörr Tobias
Published: April 2021

Synthesis and turnover of the bacterial cell wall must be tightly coordinated to avoid structural integrity failure and cell death. Details of this coordination are poorly understood, particularly if and how cell wall turnover enzymes are required for the activity of the different cell wall synthesis machines, the aPBPs and the Rod system.
The Role of the Microbiome in Autism: All That We Know about All That We Don’t Know
Authors: David Maude M.
Published: April 2021

Autism spectrum disorder (ASD) is an overly complex disorder influenced by both genetic and environmental factors. Numerous microbial diversity surveys conducted over the past decade have attempted to link specific ASD biomarkers to gastrointestinal tract disturbances, but results generated across cohorts and studies remain inconsistent.
Outer forearc uplift and exhumation during high-flux magmatism: Evidence from detrital zircon geochemistry of the Nacimiento forearc basin, California, USA
Authors: Johnston Scott M. , Kylander-Clark Andrew R.C.
Published: April 2021

We present new coupled detrital zircon trace-element and U–Pb age data from Valanginian–Santonian strata of the Nacimiento forearc basin (California, USA) to enhance provenance discrimination and investigate the evolution of the late Mesozoic California margin. Our data document at least five different Jurassic–earliest Cretaceous zircon populations with variable U/Yb ratios, and zircon that displays systematically increasing U/Yb from 130 to 80 Ma. Based on the presence of a distinctive population of geochemically primitive, 168–157 Ma low-U/Yb zircon that is found in Albian–Lower Cenomanian strata but not in older Valanginian strata, we infer a period of uplift and Albian–early Cenomanian erosion of forearc basement (the Coast Range ophiolite) that was coincident with increasing Cordilleran arc magmatic flux.
Vaginal bleeding in a misdiagnosed Mayer-Rokitansky-Küster-Hauser syndrome
Authors: Tugues Mireia , Nuñez Bernardo , Corripio Raquel
Published: April 2021

The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a spectrum of anomalies arising from incomplete development of the Müllerian ducts, is characterised by congenital aplasia of the uterus and upper part of the vagina, often in the absence of other phenotypical abnormalities. We report the case of a 13-year-old girl referred to our endocrinology unit after an incidental finding of uterine agenesis during laparoscopy to correct suspected ovarian torsion. Initial transabdominal ultrasonography found no uterus. Given her normal secondary sex characteristics, karyotype and hormone profile, MRKH syndrome was initially diagnosed. However, after vaginal bleeding compatible with menstruation, repeat transabdominal ultrasonography and MRI revealed a left-deviated unicornuate uterus.
Improving mealtimes for patients and staff within an eating disorder unit: understanding of the problem and first intervention during the pandemic—an initial report
Authors: Gardner Lucy , Trueman Hayley
Published: April 2021

Background

Mealtimes occur six times a day on eating disorder (ED) inpatient units and are a mainstay of treatment for EDs. However, these are often distressing and anxiety provoking times for patients and staff. A product of patients’ distress is an increase in ED behaviours specific to mealtimes. The aim of this quality improvement project was to decrease the number of ED behaviours at mealtimes in the dining room through the implementation of initiatives identified through diagnostic work.

Methods

The Model for Improvement was used as the systematic approach for this project. Baseline assessment included observations in the dining room, gathering of qualitative feedback from staff and patients and the development of an ED behaviours form used by patients and staff. The first change idea of a host role in the dining room was introduced, and the impact was assessed.

Results

The introduction of the host role has reduced the average number of ED behaviours per patient in the dining room by 35%. Postintervention feedback demonstrated that the introduction of the host role tackled the disorganisation and chaotic feeling in the dining room which in turn has reduced distress and anxiety for patients and staff.

Conclusions

This paper shows the realities of a quality improvement (QI) project on an ED inpatient unit during the COVID-19 pandemic. The results are positive for changes made; however, a large challenge, as described has been staff engagement.
Optimising cardiovascular care of patients with multiple myeloma
Authors: Fontes Oliveira Marta , Naaktgeboren Willeke R , Hua Alina , Ghosh Arjun K , Oakervee Heather , Hallam Simon , Manisty Charlotte
Published: April 2021

Multiple myeloma (MM) is the third most common haematological malignancy, with increasing prevalence over recent years. Advances in therapy have improved survival, changing the clinical course of MM into a chronic condition and meaning that management of comorbidities is fundamental to improve clinical outcomes. Cardiovascular (CV) events affect up to 7.5% of individuals with MM, due to a combination of patient, disease and treatment-related factors and adversely impact survival. MM typically affects older people, many with pre-existing CV risk factors or established CV disease, and the disease itself can cause renal impairment, anaemia and hyperviscosity, which exacerabate these further. Up to 15% of patients with MM develop systemic amyloidosis, with prognosis determined by the extent of cardiac involvement. Management of MM generally involves administration of multiple treatment lines over several years as disease progresses, with many drug classes associated with adverse CV effects including high rates of venous and arterial thrombosis alongside heart failure. Recommendations for holistic management of patients with MM now include routine baseline risk stratification including ECG and echocardiography and administration of thromboprophylaxis drugs for patients treated with immunomodulatory drugs. Close surveillance of high-risk patients with collaboration between haematology and cardiology is required, with prompt investigation in the event of CV symptoms, in order to identify and treat complications early. Decisions regarding discontinuation of cardiotoxic therapies should be made in a multidisciplinary setting, taking into account the severity of the complication, prognosis, expected benefits and the availability of effective alternatives.
Clinical and subclinical findings in heterozygous ABCC6 carriers: results from a Belgian cohort and clinical practice guidelines
Authors: Nollet Lukas , Campens Laurence , De Zaeytijd Julie , Leroy Bart , Hemelsoet Dimitri , Coucke Paul J , Vanakker Olivier M
Published: April 2021

Background

Biallelic pathogenic variants in the ATP-binding cassette subfamily C member 6 (ABCC6) gene cause pseudoxanthoma elasticum, a multisystemic ectopic calcification disorder, while heterozygous ABCC6 variants are associated with an increased risk of cardiovascular and cerebrovascular disease. As the prevalence of pathogenic ABCC6 variants in the general population is estimated at ~1%, identifying additional ABCC6-related (sub)clinical manifestations in heterozygous carriers is of the utmost importance to reduce this burden of disease. Here, we present a large Belgian cohort of heterozygous ABCC6 carriers with comprehensive clinical, biochemical and imaging data. Based on these results, we formulate clinical practice guidelines regarding screening, preventive measures and follow-up of ABCC6 carriers.

Methods

The phenotype of 56 individuals carrying heterozygous pathogenic ABCC6 variants was assessed using clinical (eg, detailed ophthalmological examinations), biochemical, imaging (eg, cardiovascular and abdominal ultrasound) and genetic data. Clinical practice guidelines were then drawn up.

Results

We found that ABCC6 heterozygosity is associated with distinct retinal alterations (‘comet-like’) (24%), high prevalence of hypercholesterolaemia (>75%) and diastolic dysfunction (33%), accelerated lower limb atherosclerosis and medial vascular disease, abdominal organ calcification (26%) and testicular microlithiasis (28%), though with highly variable expression.

Conclusion

In this study, we delineated the multisystemic ABCC6 heterozygosity phenotype characterised by retinal alterations, aberrant lipid metabolism, diastolic dysfunction and increased vascular, abdominal and testicular calcifications. Our clinical practice guidelines aimed to improve early diagnosis, treatment and follow-up of ABCC6-related health problems.
Approximate energy spectra and statistical mechanical functions of some diatomic molecular hydrides
Authors: Ikot A.N. , Okorie U.S. , Rampho G.J. , Abdullah Hewa Y.
Published: April 2021

In this study, we have investigated the statistical mechanical properties of the Varshni potential model for some diatomic molecular hydrides via the Euler–Maclaurin formula. This was done using the approximate analytical energy eigenvalues, which were obtained by solving the radial Schrödinger equation with the Greene–Aldrich approximation and suitable coordinate transformation schemes. The effect of high temperatures and upper bound vibration quantum number on the vibrational partition function and other thermodynamic functions of the selected diatomic molecular hydrides were studied. We also show that these effects on the thermodynamic functions considered were similar for all the diatomic molecular hydrides selected.