bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards a dynamic photosynthesis model to guide yield improvement in C4 crops
Authors: Wang Yu , Chan Kher Xing , Long Stephen P.
Published: June 2021

The most productive C4 food and biofuel crops, such as Saccharum officinarum (sugarcane), Sorghum bicolor (sorghum) and Zea mays (maize), all use NADP‐ME‐type C4 photosynthesis. Despite high productivities, these crops fall well short of the theoretical maximum solar conversion efficiency of 6%. Understanding the basis of these inefficiencies is key for bioengineering and breeding strategies to increase the sustainable productivity of these major C4 crops. Photosynthesis is studied predominantly at steady state in saturating light. In field stands of these crops light is continually changing, and often with rapid fluctuations. Although light may change in a second, the adjustment of photosynthesis may take many minutes, leading to inefficiencies. We measured the rates of CO2 uptake and stomatal conductance of maize, sorghum and sugarcane under fluctuating light regimes. The gas exchange results were combined with a new dynamic photosynthesis model to infer the limiting factors under non‐steady‐state conditions. The dynamic photosynthesis model was developed from an existing C4 metabolic model for maize and extended to include: (i) post‐translational regulation of key photosynthetic enzymes and their temperature responses; (ii) dynamic stomatal conductance; and (iii) leaf energy balance. Testing the model outputs against measured rates of leaf CO2 uptake and stomatal conductance in the three C4 crops indicated that Rubisco activase, the pyruvate phosphate dikinase regulatory protein and stomatal conductance are the major limitations to the efficiency of NADP‐ME‐type C4 photosynthesis during dark‐to‐high light transitions. We propose that the level of influence of these limiting factors make them targets for bioengineering the improved photosynthetic efficiency of these key crops.
Whole truths but half the blood: Addressing the gap between the evidence and practice of pre‐hospital and in‐hospital blood product use for trauma resuscitation
Authors: Hashmi Zain G. , Chehab Mohamad , Nathens Avery B. , Joseph Bellal , Bank Eric A. , Jansen Jan O. , Holcomb John B.
Published: June 2021

Background

In recent years, several studies have demonstrated the efficacy of using pre‐hospital blood product and in‐hospital whole blood for trauma resuscitation. While some observations suggest an encouraging uptake of this evidence by emergency medical service (EMS) agencies and trauma centers, a nationwide characterization of blood product utilization for bleeding trauma patients remains unknown. The objective of this study is to determine nationwide estimates of pre‐hospital blood product and in‐hospital whole blood utilization for trauma resuscitation.

Study Design and Methods

All adult trauma patients reported to the National Emergency Medical Services Information System (NEMSIS) dataset 2019 were included. Proportions of patients who received any pre‐hospital blood product were calculated. The American College of Surgeons (ACS) Trauma Quality Programs (TQP) databases 2015–2017 and first quarter of 2020 were used to calculate the proportion of ACS‐verified trauma centers that transfused whole blood.

Results

Among a total of 3,058,804 pre‐hospital trauma patients, only 313 (0.01%) received any blood transfusion; 208 (0.21%) patients with systolic blood pressure (SBP) ≤90 mmHg and 121 (0.67%) patients with SBP ≤90 mmHg and heart rate ≥120 beats per minute received any blood product. The proportion of ACS‐verified trauma centers transfusing whole blood increased from 16.7% (45/269) in 2015 to 24.5% (123/502) in first quarter of 2020.

Discussion

Despite strong evidence and recommendations, pre‐hospital utilization of blood products for trauma resuscitation remains low. Additionally, while the overall in‐hospital whole blood use also remains low, its use has increased at ACS‐verified trauma centers over the past 5 years.
Surgical treatment of canine and feline descemetoceles, deep and perforated corneal ulcers with autologous buccal mucous membrane grafts
Authors: Mezzadri Valentina , Crotti Alberto , Nardi Samanta , Barsotti Giovanni
Published: June 2021

Objectives

To report the surgical technique and postoperative outcome of corneal repair with autologous buccal mucous membrane grafts in dogs and cats with descemetoceles, deep corneal ulcers, and perforated corneal ulcers with or without iris prolapse.

Animal studied

Twelve cats (13 eyes) and fourteen dogs (14 eyes) were treated.

Procedures

Grafts were harvested from the unpigmented superior labial mucosa using a biopsy punch. The corneal lesion was carefully debrided and cleaned. The graft was secured to the healthy cornea with a combination of simple interrupted and continuous 9–0 polyglycolic acid sutures. In 25/27 treated eyes, an overlying pedicle conjunctival graft was also performed. A temporary nictitating membrane flap was used in all cases. The pedicle conjunctival graft was trimmed about 10–20 days postoperatively. The median follow‐up period was 549.2 days (range 14–2691 days).

Results

No surgical intra‐operative complications were observed. The ulcers healed and the integrity of the globe was restored in 24/27 treated eyes. Different grades of corneal fibrosis and/or vascularization and/or pigmentation were observed in all cases at the long‐term follow‐up. In two cases, enucleation was performed due to postoperative complications and one animal developed phthisis bulbi. A total of 22/27 treated eyes appeared to have regained effective visual function at the last clinical evaluation.

Conclusions

Autologous buccal mucous membrane grafts appear to successfully manage severe corneal ulcers in dogs and cats, providing a useful and economical alternative to other corneal grafts.
From cyberspace to cyberspatialities?
Authors: Ferreira Daniela , Vale Mário
Published: June 2021

This paper is a short reflection on the evolution of the meaning of the term cyberspace for geographers. We argue that the concept of cyberspace has become a rhizomatic one as spatial thinkers have unveiled its complex inner and outer networkings. While cyberspace was initially understood as a new open space ripe for exploration, its intricate connections with real space through the technological infrastructures that make cyberspace possible have led geographers to consider the multiple points of access and types of cyberspace. More recently, there has been renewed attention to the inner geographies of cyberspace and its cyberdivides have been exposed. We briefly retrace this evolution to argue that the way forward is to shift from an idea of cyberspace as a predefined space to a notion of cyberspatialities as ongoing spatial digital formations.
Discourse in a modern Arctic: can we supplant sovereignty? – commentary to Pawliw, Berthold and Lasserre
Authors: Carleton Alexandra
Published: June 2021

In this reflection I contemplate on the nature of claiming sovereignty over the Arctic through the political discourse, as used in the Harper administration. I question the mobilization of discourses to substantiate claims and lasting jurisdiction over the Arctic as the true nature of reconstructing narratives. In particular, whether the truer questions are how and why we seek sovereignty over areas of wilderness and why discourse is needed at all to legitimise the goodness of such claiming.
Stability of Thin Elastic Plates Covering an Arbitrary Simply Connected Region and Subject to any Admissible Boundary Conditions
Authors: Zizicas G. A.
Published: June 2021

The Bergman method of solving boundary-value problems by means of particular solutions of the differential equation, which are constructed without reference to the boundary conditions, is applied to the problem of stability of thin elastic plates of an arbitrary simply connected shape and subject to any admissible boundary conditions. A direct method is presented for the construction of particular solutions that is applicable to both anisotropic and isotropic plates. Previous results of M. Z. Krzywoblocki for isotropic plates are obtained in a simple manner.
Numerical Analysis of Forced Vibrations of Beams
Authors: Myklestad N. O.
Published: June 2021

In this paper a simple tabular method is developed by which the vibration amplitudes, bending moments, and shear forces of a beam of variable but symmetrical cross section, carrying any number of concentrated masses and acted on by any number of harmonically varying forces, can be found. The driving forces must all have the same frequency but the phase angles may be different. The method is an extension of the one employed by the author to find natural modes of vibration of beams, but in the case of forced vibration only one application of the tabular calculations is necessary, making it essentially a far simpler problem than that of finding the natural modes. Internal damping of the beam material is easily considered and should always be taken into account if there is any danger that the forced frequency is near any one of the natural frequencies.
The Necking and the Rupture of Rods Subjected to Constant Tensile Loads
Authors: Hoff N. J.
Published: June 2021

A one-dimensional theory of the behavior of a nonlinear viscoelastic bar subjected to a constant tensile load is developed with the aid of a creep law considering secondary creep alone. The theoretical value of the time at which the bar ruptures and the shape calculated for the necked portion of the bar are in satisfactory agreement with the results of experiments.
Stresses in Curved Beams—A Tabular Method of Solution Based on Winkler’s Theory
Authors: Wright W.
Published: June 2021

The method outlined in this paper is one which is applicable to all shapes of cross section. It is quicker than the orthodox methods and, in the case of irregular or complex sections, not only quicker but also more accurate.
On the Plastic Strains in Slabs With Cutouts
Authors: Hodge P. G.
Published: June 2021

The complete elastic-plastic problem is set up for a circular slab with a central circular cutout, subjected to uniform external tension. The analysis is carried out under the assumption of generalized plane stress but with possibly finite deformations. The material is assumed to be isotropic, homogeneous, and incompressible, to yield according to the Tresca yield condition, and to satisfy Hooke’s law in the elastic domain and the plastic potential law in the plastic domain. The equations are solved by a perturbation method based on the ratio of the maximum shear stress to the shear modulus, in which each of the significant quantities, stress, displacement, and slab thickness, is expanded in a power series in this ratio. A similar technique is employed to solve the fully plastic flow problem. It is shown that for cutout radii greater than 1 per cent of the radius of the slab, the “first approximations” obtained by neglecting all but the leading term in each series are satisfactory, up to loads at which the slab becomes wholly plastic. The ratio of the maximum strain in the just fully plastic slab to that in the completely elastic slab is computed. It is found that this ratio is less than about 6 if the cutout radius is at least 1 per cent of the radius of the slab. Some observations are advanced on the case where the cutout is very small compared to the slab.
Transient Thermal Stresses in Slabs and Circular Pressure Vessels
Authors: Heisler M. P.
Published: June 2021

This paper presents the results of computations for determining transient thermal stresses in slabs and circular pressure vessels. The process of solution adopted is to substitute transient-temperature formulas into the already available stress expressions. The expressions for thermal shock are transformed by means of a simple integral theorem into a form appropriate for analyzing the thermal processes commonly used to relieve thermal shock. A new dimensionless stress parameter is defined and applied to the determination of optimum heating or cooling times of massive pressure vessels.
Constant-Strain Waves in Strings
Authors: Cole J. D. , Dougherty C. B. , Huth J. H.
Published: June 2021

A nonlinear theory is developed for constant-strain waves in elastic strings. The speed of longitudinal and transverse waves is related to the strain and tension. The results can be used to calculate tension resulting from impact and thus breaking loads. Some generalizations are suggested.
On Reinforced Circular Cutouts
Authors: Levin E.
Published: June 2021

A slab with a circular cutout is subjected to stresses in the plane of the slab. The cutout has removed material which would have participated in carrying the load; hence the slab with cutout will fail under the application of stresses which the complete slab could have supported. In order to eliminate at least part of this weakening, the slab with cutout may be reinforced by the addition of material about the cutout. Such a reinforcement may be designed in any shape. The paper is concerned with extending the results of Weiss, Prager, and Hodge (1) for a cylindrical reinforcement to a reinforcement of arbitrary shape. In particular, a method will be described for the determination of a lower bound on the collapse load for a slab with circular cutout and a general reinforcement.
The Wave Method for Solving Flexural Vibration Problems
Authors: Jones R. P. N.
Published: June 2021

In this paper the use of normal mode and wave methods in problems of dynamic loading on beams is discussed, and the methods are applied to simple problems of uniform beams under a suddenly applied load. For these problems, mathematically exact results have been obtained, enabling a comparison to be made between the two types of solution. Experimental results for these problems also have been obtained, using an apparatus which releases the beam from a deflected position, and displays a record of the resultant response on an oscillograph screen, using a time base synchronized with the release of the beam. Good agreement is obtained between the experimental and theoretical results, and it is shown that the wave solution is useful for determining the initial response of the beam, while the subsequent response can be better obtained from the normal-mode solution.
Stress Concentrations Around a Small Spherical or Spheroidal Inclusion on the Axis of a Circular Cylinder in Torsion
Authors: Das Sisir Chandra
Published: June 2021

Stresses are calculated for the case of a small elastic inclusion bonded (i.e., continuous displacements and tractions across the surface of the inclusion) to a large circular cylindrical shaft. The inclusions considered are of spherical and spheroidal shapes. The results are discussed for several particular cases.
Plastic Flow in a Rectangularly Notched Bar Subjected to Tension
Authors: Lee E. H.
Published: June 2021

A two-dimensional notched bar with rectangular root pulled in tension is considered. Large strains are analyzed so that plastic-rigid theory can be used. The initial motion based on the undeformed boundaries is considered, and also the subsequent flow including the deformation of the notch boundaries. In the absence of fracture, the solution can be continued until only line contact occurs at the notch root. The solution satisfies stress and velocity conditions for a St. Venant-Mises material in plastic flow at each stage of the deformation. The unsteady, large strain, motion can be analyzed, including the determination of the unknown free surface and the plastic-rigid boundary, due to a special property of the velocity solution and to the statical determinacy of the stress field in terms of the free-surface geometry.
Transmission of Tension From a Bar to a Plate
Authors: Goodier J. N. , Hsu C. S.
Published: June 2021

When a bar or strip is lap-jointed to a plate, and transmits tension to it, the transmission is not effected only by a smooth distribution of force along the lap joint; there is also a highly concentrated force, a considerable fraction of the total tension, where the bar meets the plate, and a second force at the end of the bar. These forces are investigated by strain-gage measurements for various lengths of lap, and by a plane-stress calculation, with fair agreement. The results suggest that the fatigue strength of such joints will depend on the detailed local character of the joint where the bar meets the plate, rather than on the length of the joint.
On the Equations of Motion of Cylindrical Shells
Authors: Naghdi P. M. , Berry J. G.
Published: June 2021

From the basic equations of thin cylindrical shells consistent with Love’s first approximation, three uncoupled displacement equations of motion are deduced, the effect of rotary inertia being neglected. Comparison is made with the works of other authors who have used a variety of approximations in arriving at the equations of motion of cylindrical shells. Thus, in a qualitative manner, further insight is gained as to the effectiveness and practicality of these approximations in the solutions of problems of cylindrical shells.
On the Thickness of Normal Shock Waves in a Perfect Gas
Authors: Shapiro A. H. , Kline S. J.
Published: June 2021

An approximate method for calculating the thickness of shocks in perfect gases, similar to the integral methods of ordinary boundary-layer theory, is formulated and leads to an explicit formula relating a shock-thickness Reynolds number to the Prandtl number, ratio of specific heats, and Mach number entering the shock. The method takes account of the variation of viscosity with temperature. The results of the approximate theory are in exact accord with the known exact solutions for (a) the case where the Prandtl number is 3/4 and the viscosity and heat conductivity are constant, (b) the case where the shock is very weak, and (c) the case where the gas has finite viscosity but zero conductivity. In addition, the approximate theory is in good agreement with results obtained on a differential analyzer showing the effects of Prandtl number and variation of viscosity with temperature. The results also are expressed in terms of the ratio of shock thickness to mean free molecular path in the inlet gas. This ratio is given in terms of the Prandtl number, ratio of specific heats, and shock strength. In the absence of relaxation effects, the numerical magnitudes suggest that the continuum theory is accurate for inlet Mach numbers below about 1.5, whereas for higher Mach numbers the continuum theory is indicative of general orders of magnitude.
A Critical Examination of Procedures Used in Britain and the United States to Determine Creep Stresses for the Design of Power Plant for Long Life at High Temperatures
Authors: Bailey R. W.
Published: June 2021

The operating life of land power plant being far longer than allowable testing times for the constructional metals, the selection of a material, or the determination of its appropriate working stress, is dependent in an important degree upon the procedure followed in utilizing the creep-test results obtained. Different procedures practiced both in Britain and in the United States can result in different views regarding the potentialities of a material, and also about the working stress allowable. The paper examines the more commonly used procedures and focuses attention upon the factors present which would operate to introduce uncertainty and error as between the probable behavior in the long time of actual service, and as yielded by a test procedure. The principal disturbing factor in altering the resistance to creep of the material is thermal action. In some procedures, especially where the creep tests are made at working temperatures, the influence of this factor may be small or negligible in the procedure, compared with its magnitude in service. The need is emphasized for thermal action to be taken adequately into account by the test procedure. Next in importance as a possible source of error is the method of extrapolation beyond the test times to the time of the operating life. The factor of thermal action and of its representation in the several procedures examined is considered. The circumstances of extrapolation are similarly investigated, especially in regard to whether the result would overestimate or underestimate the safe working stress. Satisfying comparisons of working stresses using different procedures cannot at present be made. The position is therefore disappointing and one which it is very desirable should be rectified.
Anisotropic Loading Functions for Combined Stresses in the Plastic Range
Authors: Hu L. W. , Marin Joseph
Published: June 2021

A loading function is a relation between combined stresses for which the beginning of plastic flow takes place. The loading function for a given material is different depending upon the initial plastic strains produced. That is, the initial stress or strain history influences the subsequent loading function. This paper gives the results of an experimental investigation to determine the validity of certain loading functions proposed for anisotropic materials. The study reported was conducted for an aluminum alloy 24S-T and the state of stress covered was biaxial tension. These stresses were produced in the usual way by subjecting thin-walled tubular specimens to axial tension and internal pressure. The test results showed that none of the existing loading functions is adequate for interpreting the plastic stress-strain relations obtained. Tests also were made to determine the change in the loading function with increase in plastic flow. It was found that the loading function did not remain symmetrical with respect to the original function, nor was the new loading function the same as the original except for a shift of origin. However, the test results support in a qualitative way the concept of the so-called “yield corner.”
Harmonic Oscillations of Nonlinear Two-Degree-of-Freedom Systems
Authors: Huang T. C.
Published: June 2021

In this paper an investigation is made of equations governing the oscillations of a nonlinear system in two degrees of freedom. Analyses of harmonic oscillations are illustrated for the cases of (1) the forced oscillations with nonlinear restoring force, damping neglected; (2) the free oscillations with nonlinear restoring force, damping neglected; and (3) the forced oscillations with nonlinear restoring force, small viscous damping considered. Amplitudes of oscillations and frequency equations are derived based on the mathematically justified perturbation method. Response curves are then plotted.
The Effect of a Surrounding Fluid on Pressure Waves in a Fluid-Filled Elastic Tube
Authors: Junger M. C.
Published: June 2021

The analysis of the transmission of pressure waves in a fluid-filled elastic tube has been extended to the case where the tube is surrounded by a fluid medium. The sound pressure inside the tube is the resultant of a number of modes, some of which are nonpropagating, while others propagate at their own characteristic phase velocities. Neglecting end effects, and for continuously generated waves, it is found that only the modes whose velocity is larger than the sound velocity of the surrounding medium radiate sound energy radially outward. These modes will be damped out by radiation losses, while modes having a phase velocity smaller than this sound velocity are propagated without attenuation (if viscous and heat-transfer losses are neglected). Consequently, if the fluid is the same in the surrounding medium and in the tube only the lowest mode, which resembles a plane wave, propagates unattenuated. In any case, the mass-loading of the surrounding fluid lowers the phase velocities of the propagating modes, particularly at intermediate frequencies. It is shown that in this application the membrane theory of shells will lead to incorrect results, even in thin-walled tubes. This is illustrated by comparison with experimental data.
Stresses Due to Diametral Forces on a Circular Disk With an Eccentric Hole
Authors: Sen Gupta A. M.
Published: June 2021

In this paper stresses in a circular disk with an eccentric circular hole have been determined when the disk is compressed along the line of centers by two equal and opposite forces acting on its outer edge, the inner edge being unstressed. From the results obtained, the solution of the problem of a semi-infinite plate acted on by a concentrated normal force on its straight boundary and containing an unstressed circular hole has been deduced.
Limits of Economy of Material in Plates
Authors: Hopkins H. G. , Prager W.
Published: June 2021

The paper is concerned with the limits of economy of material in a simply supported circular plate under a uniformly distributed transverse load. The plate material is supposed to be plastic-rigid and to obey Tresca’s yield condition and the associated flow rule. The criterion of failure adopted is that used in limit analysis. It is shown that the plate of uniform thickness has a weight efficiency of about 82 per cent. Stepped plates of segmentwise constant thickness are discussed, and the plate of continuously varying thickness is treated as the limiting case obtained by letting the number of steps go to infinity.
Response Curves for a System With Softening Restoring Force
Authors: Abramson H. N.
Published: June 2021

The purpose of this note is to present, and discuss briefly, calculated response curves for the nonlinear system titled. Several features of the response curves peculiar to this type of system, not previously discussed in the literature, are pointed out.
Theory of Plastic Buckling of Plates and Application to Simply Supported Plates Subjected to Bending or Eccentric Compression in Their Plane
Authors: Bijlaard P. P.
Published: June 2021

After some general considerations on the plastic buckling of plates, the plastic buckling stresses are calculated for long plates, subject to longitudinal bending or eccentric compression in their plane, and simply supported at their unloaded edges. The solutions are based on the author’s theory of plastic plate buckling and are obtained by reducing the governing partial differential equation to ordinary finite-difference equations. Second-order finite differences are used, with a spacing equal to one ninth of the plate width. A simple design formula is presented for the plastic reduction factor with which the elastic buckling stress has to be multiplied for obtaining the plastic buckling stress.
On Axially Symmetric Bending of Nearly Cylindrical Shells of Revolution
Authors: Clark R. A. , Reissner E.
Published: June 2021

The words “nearly cylindrical” are used in this paper to describe a thin elastic shell of revolution which is such that (a) the maximum variation of the radial dimension is small compared to the average radial dimension, and (b) the rate of change of the radial dimension with respect to the axial dimension is small compared to unity. For any particular type of loading a nearly cylindrical shell may or may not exhibit a behavior similar to that of a shell which is exactly cylindrical. The purpose of this paper is to demonstrate this fact and to present a method for obtaining approximate solutions for the stresses and deflections in either event. The method involves a perturbation procedure based on the assumption that all desired quantities can be represented as expansions in powers of two small parameters. The procedure leads to a set of linear differential equations with constant coefficients, which may be solved successively.
General Solutions of the Equations of Elasticity and Consolidation for a Porous Material
Authors: Biot M. A.
Published: June 2021

Equations of elasticity and consolidation for a porous elastic material containing a fluid have been previously established (1, 5). General solutions of these equations for the isotropic case are developed, giving directly the displacement field or the stress field in analogy with the Boussinesq-Papkovitch solution and the stress functions of the theory of elasticity. General properties of the solutions also are examined and the viewpoint of eigenfunctions in consolidation problems is introduced.
Analysis of Creep in Rotating Disks Based on the Tresca Criterion and Associated Flow Rule
Authors: Wahl A. M.
Published: June 2021

An analysis of creep deformations in rotating disks based on the Tresca criterion and the associated flow rule is presented. Assuming steady-state creep conditions and a creep rate equal to a function of stress times a function of time, the method is applied to the following cases: (a) Disk with constant thickness and constant temperature, (b) disk with variable thickness and constant temperature, and (c) disk with variable thickness and variable temperature. In many cases, the equations can be expressed in closed form. Comparison is made with test results on rotating disks at elevated temperature as reported in a previous paper. Based on certain stress-creep-rate relations, the method is also applied to the problem of calculating the transient change in stress when the stress distribution changes from an initial to a steady-state condition during the starting period. It is suggested that the simplification effected by the use of these methods may be of value for design purposes pending the development of more accurate methods based on test results.
Stress Solutions for an Infinite Plate With Triangular Inlay
Authors: Evan-Iwanowski R. M.
Published: June 2021

The method of solving two-dimensional problems in elasticity by means of the functions of complex variable, essentially developed by É. Goursat (1), and N. I. Muskhelishvili (2-4), has been applied to the following cases: (a) An infinite plate with a rigid triangular inlay under uniform tension at infinity; (b) A concentrated force; and (c) a moment acting on a triangular inlay in an infinite plate. All these problems are second boundary-value problems; i.e., the displacements are prescribed on the boundary. The first boundary-value problem for a triangular opening in an infinite plate was treated by Hu-Nan Chu (7). The mapping function used in this paper is z = ω ( ζ ) = K ( ζ + n ζ 2 ) , K is real, and 0 < n < 1/2 and real, and it maps an exterior of a triangle with rounded corners, Fig. 1, in the z-plane into an exterior of a unit circle in the ζ-plane [for detailed discussion of this mapping refer to (4)].
A Method for Calculating Stress-Concentration Factors
Authors: Hetényi M. , Liu T. D.
Published: June 2021

It is shown in this paper that along the root sections of filleted or notched bars there is a rapid rise in the transmitted shearing forces, and this may be regarded as the principal reason for the occurrence of stress peaks under these circumstances. By making a few assumptions concerning the distribution of these shear loads, the stress-concentration factors can be calculated with satisfactory accuracy for such cases which have been heretofore analytically intractable.
Thermal Stresses in Infinite Elastic Disks
Authors: Sharma Brahmadev
Published: June 2021

A direct method of solving problems of thermal stress in a disk of finite thickness and infinite radius is discussed in this paper.
Three-Dimensional and Shell-Theory Analysis of Axially Symmetric Motions of Cylinders
Authors: Herrmann George , Mirsky I.
Published: June 2021

The frequency (or phase velocity) of axially symmetric free vibrations in an elastic, isotropic, circular cylinder of medium thickness is studied on the basis of the three-dimensional linear theory of elasticity and several different shell theories. To be in good agreement with the solution of the three-dimensional equations for short wave lengths, an approximate theory has to include the influence of rotatory inertia and transverse shear deformation, for example, in a manner similar to Mindlin’s plate theory. A shell theory of this (Timoshenko) type is deduced from the three-dimensional elasticity theory. From a comparison of phase velocities it appears that, to a good approximation, membrane and curvature effects on one hand, and on the other hand, flexural, rotatory-inertia, and shear-deformation effects are mutually exclusive in two ranges of wave lengths, separated by a “transition” wave length. Thus, in the full range of wave lengths, the associated lowest phase velocities may be determined on the basis of the membrane shell theory (for wave lengths larger than the transition wave length) and on the basis of Mindlin’s plate theory (for wave lengths smaller than the transition wave length).
A framework for the analysis and optimization of adaptive psychophysical procedures
Authors: Hoover Eric C.
Published: June 2021

Remote testing platforms have proven to be a viable tool for hearing research, but the ability to obtain efficient and reliable data remains a significant barrier. Adaptive up-down procedures are widely used to estimate hearing abilities because they can be performed easily with minimal assumptions about underlying mechanisms. However, they are inefficient compared to parametric alternatives, and the optimization of starting level, step size, stopping rule, and other factors continues to rely on trial and error. This reflects the limitations of our theoretical understanding, which cannot explain the complex, multi-component error patterns observed in thresholds obtained in controlled simulations. The present study reports on the development of a mathematical framework for nonparametric psychophysical procedures. A method will be described for creating models of the combined listener-procedure system as an equivalence class of directed graphs. The model can be used to calculate the trial-by-trial and asymptotic stimulus distributions for ascending and descending trials, the rate of convergence, and other fundamental properties. Using this approach, stimulus selection, stopping, and threshold calculation can be optimized with typical minimization procedures. Insights about the mathematical structure of psychophysical procedures promise to drive the development of novel tools to address the needs of remote test administration.
Acoustic and thermoacoustic properties of an additive manufactured lattice structure
Authors: Di Giulio Elio , Auriemma Fabio , Napolitano Marialuisa , Dragonetti Raffaele
Published: June 2021

With the advent of additive manufacturing, lattice structures can be printed with precisely controlled geometries. In this way, it is possible to realize porous samples with specific acoustic and thermoacoustic characteristics. However, to this aim and prior to the manufacturing process, it is fundamental to have a design tool that can predict the behaviour of the lattices. In the literature, Luu, Perrot, and Panneton [Acta Acust. United Ac. 103, 1050 (2017)] provide a model to characterize transport parameters of fibrous material with a certain fiber orientation with respect to the direction of wave propagation. In this work, finite element numerical simulations are used to improve their model in order to compute the thermoviscous functions of lattice structures composed of cylindrical struts arranged in Tetragonal Body Centred cells. New correlations for transport parameters are suggested, which are finally coupled with the semi-phenomenological model of Johnson-Champoux-Allard-Lafarge to obtain the complex density and bulk modulus of the equivalent fluid. These results are compared with the measurements carried out on two 3-dimensional-printed samples with hybrid impedance tube techniques.
Inference and influence of network structure using snapshot social behavior without network data
Authors: Godoy-Lorite Antonia , Jones Nick S.
Published: June 2021

Inference method uncovers homophilic network structures and behavior from only a single snapshot of population behavioral data.
PDLLA-Zn-nitrided Fe bioresorbable scaffold with 53-μm-thick metallic struts and tunable multistage biodegradation function
Authors: Shen Danni , Qi Haiping , Lin Wenjiao , Zhang Wanqian , Bian Dong , Shi Xiaoli , Qin Li , Zhang Gui , Fu Wenchao , Dou Kefei , Xu Bo , Yin Zhenyuan , Rao Jiancun , Alwi Mazeni , Wang Shuhan , Zheng Yufeng , Zhang Deyuan , Gao Runlin
Published: June 2021

A novel PDLLA-Zn-FeN BRS biodegrades completely after ~2 years in rabbits and humans, with excellent biocompatibility.
A conserved rRNA switch is central to decoding site maturation on the small ribosomal subunit
Authors: Schedlbauer Andreas , Iturrioz Idoia , Ochoa-Lizarralde Borja , Diercks Tammo , López-Alonso Jorge Pedro , Lavin José Luis , Kaminishi Tatsuya , Çapuni Retina , Dhimole Neha , de Astigarraga Elisa , Gil-Carton David , Fucini Paola , Connell Sean R.
Published: June 2021

This study highlights the molecular mechanisms of four assembly factors in folding the ribosomal central decoding region.
Anisotropic nanocrystal shape and ligand design for co-assembly
Authors: Elbert Katherine C. , Zygmunt William , Vo Thi , Vara Corbin M. , Rosen Daniel J. , Krook Nadia M. , Glotzer Sharon C. , Murray Christopher B.
Published: June 2021

Computationally guided ligand selection for enhanced co-assembly of noncomplementary nanocrystals.
Enhanced avionic sensing based on Wigner’s cusp anomalies
Authors: Kononchuk Rodion , Feinberg Joshua , Knee Joseph , Kottos Tsampikos
Published: June 2021

Differential cross-sectional cusps, occurring at the vicinity of newly open channels, are used for enhanced avionic sensing.
Effect of Detergents on Streptolysin S Precursor
Authors: Calandra Gary B.
Published: June 2021

Group A streptococci which produce streptolysin S contain a cellular precursor to streptolysin S in the membranes and cytoplasm which is activatable by blending in a Vortex mixer with glass beads and ribonucleic acid (RNA)-core (RNA preparation from yeast). Although no activation of precursor occurred when it was mixed with detergents, it was activated when blended with glass beads and detergents such as Tergitol NP-40 and Brij 35. Maximum activation of precursor was achieved in 1 to 2% detergent, in pH 6.5 buffer, and after 8 min of blending. Detergents Tween 20, 40, 60, and 80, Brij 56, and Lubrol WX also activated precursor, but, of all the hemolysin preparations, those with Tween 40 or 60 or Lubrol WX were the most stable. The addition of RNA-core during or after blending of precursor with detergents enhanced the titer and stability of the hemolysin. This was due in part to the association of the hemolytic moiety with RNA-core. Activation of precursor in the membrane was better with a detergent, whereas that in the cytoplasm was better with RNA-core. Therefore, precursor from two different cellular locations can be differentiated by the effects of RNA-core and detergents on precursor titer.
Influence of complement on the chemiluminescent response of human leukocytes to immune complex
Authors: Löfgren S , Tärnvik A , Carlsson J
Published: June 2021

Vaccine bacteria of Francisella tularensis were mixed with human serum containing specific antibodies against the same organism, and the mixture was incubated at 37 degrees C for 30 min. The mixture induced a two-peak chemiluminescent response in polymorphonuclear leukocytes. The initial peak was induced by a soluble agent, formed during incubation. The formation of this agent involved the activation of complement component C5. The second peak of the chemiluminescent response was induced by the opsonized bacteria; this peak was augmented by complement component C3, whereas C5 had no influence.
Serological differentiation between infected and vaccinated cattle by using purified soluble antigens from Brucella abortus in a hemagglutination system
Authors: Raybould T J , Chantler S
Published: June 2021

Serological tests used in current brucellosis eradication schemes, such as bacterial tube agglutination, do not readily distinguish between infected animals and those immunized with strain 19 or 45/20 Brucella abortus vaccines. In this study, sera from naturally infected cattle were used to identify serologically important antigens in extracts of virulent B. abortus by gel diffusion techniques. Antisera from rabbits hyperimmunized with selected precipitation lines were used for purification by affinity chromatography of two precipitating and one non-precipitating antigen from crude bacterial extracts. A passive hemagglutination test using these antigens was developed. A number of characterized bovine sera were screened by passive hemagglutination and conventional bacterial tube agglutination test. A considerable improvement in discrimination between sera from infected and vaccinated cattle was obtained with the hemagglutination test compared with bacterial tube agglutination.
Hydrogen Peroxide-Releasing Function of Chemically Elicited and Immunologically Activated Macrophages: Differential Response to Wheat Germ Lectin and Concanavalin A
Authors: Tomioka Haruaki , Saito Hajime
Published: June 2021

Various types of mouse peritoneal macrophages were studied for H
2
O
2
release in the presence of wheat germ lectin or phorbol myristate acetate. Macrophages elicited 3 days before harvest by a single injection of thioglycolate, zymosan A, or a streptococcal preparation (OK-432) were highly responsive to wheat germ lectin, resulting in a marked increase in H
2
O
2
release. However, immunologically activated macrophages induced by double injections of live and heat-killed BCG at 15 and 3 days before harvest or by double injections of zymosan A or OK-432 at 20 and 3 days before harvest did not show any significant response to wheat germ lectin. On the other hand, all macrophages tested responded well to phorbol myristate acetate by augmentation of H
2
O
2
release. Concanavalin A inhibited wheat germ lectin- and phorbol myristate acetate-triggered H
2
O
2
release from all types of macrophages, but inhibition was much more marked in the case of wheat germ lectin-stimulated H
2
O
2
release. Succinylated concanavalin A (divalent concanavalin A) showed only slight suppressive action against macrophage H
2
O
2
release, and prostaglandin E
1
and dibutyryl cyclic adenosine 3′, 5′-monophosphate caused depression of H
2
O
2
release from OK-432-induced macrophages.
Polyvalent antisera to Pseudomonas ribosomal vaccines: protection of mice against clinically isolated strains
Authors: Lieberman M M , Wright G L , Wolcott K M , McKissock-Desoto D C
Published: June 2021

The preparation of polyvalent antisera to ribosomal vaccines from Pseudomonas aeruginosa is described. The ability of these antisera to protect mice by passive immunization against challenge with randomly chosen, clinically isolated strains of P. aeruginosa is reported. Significant protection was achieved against 34 of 40 strains tested (85%). Included among these strains against which protection was achieved were four mucoid strains. In addition, the degree of cross-protection attainable by the ribosomal vaccines was investigated. The results obtained indicated that these vaccines are generally serotype specific.
Amplified Migration Inhibition Effect
Authors: Philp J. R. , Huffman A. L. , DeChatelet L. R. , Johnson J. E.
Published: June 2021

When tuberculin-sensitive peritoneal exudate cells are incubated in a culture flask with tuberculin purified protein derivative, macrophage inhibition factor and other lymphokines are released into the culture medium. We have described how, if incubation is carried out in a stationary conical culture tube, intercellular contact between the peritoneal exudate cells is facilitated as the cells sediment into a pellicle at the bottom of the tube. This results in augmented release of inhibitory lymphokines into the supernatant culture medium with titers up to 10
9
times greater than those obtained by conventional culture methods using a flatbottomed culture dish or flask. When such high-titered inhibitory supernatants were subjected to fractionation by sequential Amicon ultrafiltration, two clearly distinct macrophage-inhibitory lymphokines were found. The first was present, after fractionation, in a titer of 10
12
, had a molecular weight in the range of 50,000 to 100,000, and was heat stable at 56°C for 1 h. This moiety is probably identical to guinea pig macrophage inhibition factor. Unexpectedly, a second heat-labile inhibitory substance with a molecular weight between 500 and 1,000 was found in a titer of 10
4
after fractionation. This low-molecular-weight, heat-labile material may represent a new lymphokine with a direct inhibitory action on macrophage migration. Theoretically, the data are also consistent with the possibility that it could act as a chemical immunotransmitter which stimulates amplified production of macrophage inhibition factor by lymphocytes within the cell pellicle and leads indirectly to inhibition of macrophage migration.
Outcome of Influenza Infection: Effect of Site of Initial Infection and Heterotypic Immunity
Authors: Yetter Robert A. , Lehrer Shoshana , Ramphal Reuben , Small Parker A.
Published: June 2021

An infection established throughout the total respiratory tract of mice with a highly lung adapted influenza virus (H0N1) led to death from viral pneumonia. The 50% lethal dose (LD
50
) was approximately the same as the 50% infectious dose (ID
50
). An infection with the same virus initiated in the nasal mucosa spread to the trachea and lungs over a 3- to 5-day period but was not lethal except at very high infecting doses. The LD
50
was 30,000 times the ID
50
. Mice that had recovered from a prior infection with A/PC/73(H3N2) demonstrated enhanced recovery (heterotypic immunity) when challenged with A/PR/8/34(H0N1). Heterotypically immune mice infected while anesthetized with this potentially lethal virus stopped shedding virus from the nose, trachea, and lungs by day 7 and recovered. Heterotypically immune mice, infected awake, stopped shedding virus from the nose by day 5, and, in fact, the virus did not spread to the trachea or lungs. Thus, some of the variation in the severity of influenza infections may be explained by two factors: the site of initial infection and previous infection with heterotypic influenza virus.
Septic choroiditis with serous retinal detachment in Streptococcus mutans-injected dogs
Authors: Meyers S M , Vasil M L
Published: June 2021

This report describes a dog model of multifocal choroiditis with serous retinal detachment after carotid injection of Streptococcus mutans. The fundus lesions occurred mainly in the tapetal area of the retina, and, on histopathologic examination, microabscesses in the choroid and subretinal space were observed.
The rat as an animal model for infant botulism
Authors: Moberg L J , Sugiyama H
Published: June 2021

Susceptibility to intraintestinal Clostridium botulinum colonization of conventional infant and germfree adult rats is comparable to that of mice. C. botulinum-monoassociated rats pass C. botulinum toxin in their milk.
Comparative study of the acquisition of antibody to Norwalk virus in pediatric populations
Authors: Cukor G , Blacklow N R , Echeverria P , Bedigian M K , Puruggan H , Basaca-Sevilla V
Published: June 2021

Analysis by radioimmunoassay of pediatric sera from three populations showed that antibody to Norwalk virus is acquired at a significantly earlier age in a less developed and tropical area (Philippines) than in two more developed and nontropical countries (United States and Taiwan).
Searches among mycobacterial cultures for antileprosy vaccines
Authors: Shepard C C , van Landingham R , Walker L L
Published: June 2021

All mycobacteria species share some antigens, so there may be cultivable mycobacterial cultures that can provide vaccine protection against leprosy. Vaccine protection against Mycobacterium leprae infections in mice has been demonstrated for M. leprae itself, as living or heat-killed suspensions, and for Mycobacterium bovis (BCG), as living suspensions. Results are reported here with 17 other cultures. The mycobacterial suspensions were injected intradermally, and the mice were challenged in the footpad with infectious suspensions of M. leprae. In two experiments the mice were also challenged by footpad injections of 10(7) heat-killed M. leprae so the footpad enlargment could be measured. That some mycobacterial suspensions were immunogenic for some of their own antigens was suggested by reactions at the vaccine site and enlargement of the regional lymph nodes. Some mycobacterial suspensions also stimulated footpad enlargement on challenge by homologous suspensions or by challenge with M. leprae suspensions. Consistent protection against infectious challenge with M. leprae was observed only with BCG and M. leprae, however.