bluuebunny/crossref_metadata_2025 huggingface dataset:
Trade direction, market access and regional wage inequality: An explanation based on asymmetric trade costs
Authors: Yu Linhui , Wang Sai , Cheng Jinwen , Yang Lihong
Published: June 2021

We introduce the trade frictions between wealthy and impoverished regions into the New Economic Geography model. We argue that to reconcile bilateral trade volumes and price data within a standard gravity model, the trade frictions between regions must be systematically asymmetric, with poor regions facing higher costs to export relative to affluent regions. We construct the corresponding econometric model based on the theoretical formulation, and the results show that the asymmetry of trade costs has a significant impact on regional market access and wages. We then argue that these trade frictions are quantitatively crucial and without the asymmetry of trade costs, the standard deviation of market access among Chinese provinces would decline by 13.9%, while that of relative wages would decline by 16.1%.
Investigación en Responsabilidad Social Empresaria y Sustentabilidad Corporativa: evolución, tensiones actuales y perspectivas futuras
Authors: Amato Celina Noé
Published: June 2021

El artículo tiene como objetivo comprender la evolución de los constructos Responsabilidad Social Empresaria y Sustentabilidad Corporativa de acuerdo con distintos paradigmas de la investigación en management, así como también las tensiones actuales y posibilidades de investigación futura. La metodología elegida es la revisión terciaria de literatura. Como resultados se destacan la situación de convergencia de ambos conceptos, que dificulta la claridad para el avance de la investigación y las críticas hacia ellos (business case, profecía autocumplida, invisibilización de stakeholders y reproducción del paradigma capitalista de producción y consumo). Las perspectivas futuras de investigación se relacionan con la profundización de cada constructo por separado, la incorporación de otras teorías y disciplinas al análisis y la integración del pensamiento de corrientes críticas.
Efectos de un programa de atención domiciliara en geriatría sobre el número de hospitalizaciones y consultas a urgencias
Authors: G´ómez Salazar Valentina , Garcés Medina María Camila , Chavarro Carvajal Diego Andrés , Meneses Bernal Juan Felipe , Cano Gutierrez Carlos Alberto , Santacruz Escudero José Manuel Ignacio
Published: June 2021

RESUMEN

Objetivo: Evaluar los efectos del programa de atención domiciliaria del Centro de Memoria y Cognición Intellectus, en un grupo de pacientes multimórbidos y dependientes con respecto al número de hospitalizaciones y consultas a urgencias antes del ingreso al programa y un año posterior al seguimiento.

Diseño: Es un estudio longitudinal de antes y después.

Participantes: Pacientes del programa de atención domiciliaria del Centro de Memoria y Cognición-Intellectus atendidos por geriatría domiciliaria con edad igual o mayor a 65 años, con enfermedades crónicas discapacitantes y/o trastorno neurocognoscitivo mayor; índice de Barthel menor de 60 y seguimiento mínimo de 1 año en el programa de atención domiciliaria.

Intervenciones: Seguimiento de un año en el programa de atención domiciliaria, y entrevista estructurada a los pacientes o familiares de los pacientes para evaluar los desenlaces.

Resultados: El promedio de hospitalizaciones se redujo de 1,91 (DE 1,82 IC 1,50-2,32) a 0,96 (DE 1,43 IC 0,66 a 1,26) con significancia estadística (p <0.001). El promedio de consultas a urgencias disminuyó de forma significativa (p <0.001) de 2,20 (DE 1.91 IC 1,77-2,63) a 1,20 (DE 1,69 IC 0,82-1,58).

Conclusiones: Se evidenció reducción en el número de vistas a urgencias e ingresos hospitalarios con diferencias estadísticamente significativas.
High-Temperature Compression Testing of Graphite
Authors: Green Leon
Published: June 2021

Experiments on the compression of graphite cylinders at elevated temperatures are described. It is found that the short-time compressive strength increases with temperature in the range from room temperature to 2000 C, a variation which is consistent with the previously reported behavior of the tensile strength. Photographs of typical modes of deformation and their corresponding stress-strain curves are presented, but a limited degree of temperature control renders the curves semiquantitative in nature. The large, mutually opposing influences of temperature and strain rate are illustrated by photographs of typical failures, and stress-relaxation curves manifest the plasticity of graphite at high temperatures.
Determination of Stresses in Cemented Lap Joints
Authors: Cornell R. W.
Published: June 2021

A variation and extension of Goland and Reissner’s (1) method of approach is presented for determining the stresses in cemented lap joints by assuming that the two lap-joint plates act like simple beams and the more elastic cement layer is an infinite number of shear and tension springs. Differential equations are set up which describe the transfer of the load in one beam through the springs to the other beam. From the solution of these differential equations a fairly complete analysis of the stresses in the lap joint is obtained. The spring-beam analogy method is applied to a particular type of lap joint, and an analysis of the stresses at the discontinuity, stress distributions, and the effects of variables on these stresses are presented. In order to check the analytical results, they are compared to photoelastic and brittle lacquer experimental results. The spring-beam analogy solution was found to give a fairly accurate presentation of the stresses in the lap joint investigated and should be useful in analyzing other cemented lap-joint structures.
The Effect of Strain Hardening in an Annular Slab
Authors: Hodge P. G.
Published: June 2021

A procedure is outlined for obtaining the stresses and strains in a circular slab with a cutout, subject to uniform biaxial tension. An arbitrary stress-strain curve in tension is approximated by any number of straight-line segments. For biaxial states of stress the material is assumed to satisfy a flow law based on the maximum shear stress, and to be incompressible throughout. The general equations are given and then simplified by assuming that boundary motions may be neglected if the strains are small, and that elastic strain components may be neglected if the strains are large. For the case of linear strain hardening a complete solution is given in closed form. If the rate of strain hardening is small, these results may be simplified further.
Laminar Swirling Pipe Flow
Authors: Talbot L.
Published: June 2021

The problem of the decay of a rotationally symmetric steady swirl superimposed on Poiseuille flow in a round pipe was investigated theoretically and experimentally. The object was to determine the degree to which the rate of decay of the swirl as predicted by a linearized theory agreed with measured rates of decay at flow conditions near the critical conditions for swirl instability. The solution to the linearized equation of motion for the swirl was obtained. Swirling flow was produced experimentally by rotating a section of the test pipe. Swirl velocities were determined from motion-picture studies of colored oil droplets introduced in the flow. The stability of the swirl was investigated through visualization of a dye filament, and a critical curve for swirl instability was determined experimentally relating the angular velocity of the rotating section to the Reynolds number. The theoretical and experimental values for the decay parameter were found to agree closely, even at conditions of flow near the critical conditions for instability. It was concluded that in the problem under consideration the nonlinear effects are not appreciable for stable decay of the swirl.
Approximate Stress Functions for Triangular Wedges
Authors: Silverman I. K.
Published: June 2021

The variational method is used to determine expressions for approximate stress functions for determining the effect of a third boundary to an infinite triangular wedge. The approximate function is a solution of a Euler-Lagrange total differential equation of the variational calculus with the constants of integration determined from the condition of least work. The approximate function yields zero stresses on the sloping faces of the wedge but furnishes correction stresses on the third boundary.
Bending of Orthogonally Stiffened Plates
Authors: Hoppmann W. H.
Published: June 2021

In this paper the flexure theory for plates of orthotropic material is applied in the case of orthogonally stiffened plates using an experimental method to determine plate stiffnesses in bending and in twisting. Once these stiffnesses, or elastic moduli, have been determined by test they may be used in calculating bending deflections for plates of identical stiffened construction but any given boundary conditions. As an example, calculated deflections of a stiffened circular plate with clamped edge are compared with those which were determined experimentally. It is also demonstrated that the theory can be applied to the case of vibration of a stiffened plate if in addition to the orthotropic elastic constants the weight per unit area of the plate is determined. The various experimental results show considerable promise for use of the proposed combination of theory and experimental method in the analysis of both statically and dynamically loaded plates with attached stiffeners.
Determination of Natural Frequencies of Continuous Plates Hinged Along Two Opposite Edges
Authors: Veletsos A. S. , Newmark N. M.
Published: June 2021

A numerical procedure is presented for computing the undamped natural frequencies of bending vibration of rectangular plates which are hinged along two opposite edges and continuous over rigid supports transverse to the hinged edges. Along the hinged edges, there are assumed to be uniformly distributed forces acting in the middle plane of the plate. The procedure is illustrated by two examples.
Momentum Diffusion From a Slot Jet Into a Moving Secondary
Authors: Weinstein A. S. , Osterle J. F. , Forstall W.
Published: June 2021

Results are presented for an experimental, impact-tube study of the diffusion of momentum for the isothermal, incompressible, turbulent mixing of a slot jet issuing into a slower moving secondary region. The symmetric spread of the jet into a uniformly flowing secondary stream of low initial turbulence is well correlated by phenomenological expressions based on assumptions suggested by the Engineering Experiment Station of the University of Illinois and extended in this paper to include the case of the slot jet issuing into a moving secondary. The single parameter upon which this correlation is based, the spreading coefficient, is shown to have an interesting interpretation in terms of the diffusion of a stream of fluid “particles” into uniformly flowing fields of homogeneous isotropic turbulence.
Minimum Weight Design of Cylindrical Shells
Authors: Freiberger Walter
Published: June 2021

The theory of collapse and minimum weight design of cylindrical shells by Onat and Prager is applied in this paper to the development of a method for designing the variable wall thickness of a cylindrical shell under axial loading and arbitrary pressures to give maximum economy of material. The design is such that the shell does not fail plastically in the sense used in limit analysis. It will be assumed that the shell is supported at the ends by inextensible rings so that the circumferential strain rates vanish there.
Dynamic Response Analysis of Gearbox to Improve Fault Detection Using Empirical Mode Decomposition and Artificial Neural Network Techniques
Authors: Desavale R. G. , Jadhav P. M. , Dharwadkar Nagaraj V.
Published: June 2021

Since the last decade, gearbox systems have been requiring increasing power, and consequently, the complexity of systems has escalated. Inevitably, this complexity has resulted in the need for the troubleshooting of gearbox systems. With a growing trend of health monitoring in rotating machines, diagnostic and prognostic studies have become focused on diagnosing existing and potential failures in gearbox systems. In this context, this study develops the architecture of the cloud-based cyber-physical system (CPS) for condition monitoring of gearbox. Empirically collected vibration signals of gear wear at various time intervals are processed using empirical mode decomposition (EMD) algorithm. A Euclidian-based distance evaluation technique is applied to select the most sensitive features of car gear wear. Artificial neural network (ANN) is trained using extracted features to monitor the gearbox for the future dataset. Comparison of the performance results revealed that the ANN is superior to the other EMD methods. The present methodology was found efficient and reliable for condition monitoring of industrial gearbox.
Modeling of Looping Behavior in a Flexible Instrument Using a Bézier Curve
Authors: Singhal Shobhit , Khatait Jitendra P.
Published: June 2021

Flexible medical instruments undergo looping during insertion and navigation inside the human body. It makes the control of the distal end difficult and raises safety concerns. This paper proposes the minimum strain energy concept to get the deformed shape of a flexible instrument in three-dimensional space. A Bézier curve is used to define the trajectory of the deformed shape under different loading conditions and constraints. Looping behavior is studied for different end shortening conditions. The effect of end twist on looping behavior is studied. It is observed that end twist leads to early onset of out-of-plane deformation leading to looping. The strain energy plot gives an insight into the behavior of these instruments with respect to end shortening and twist. The strain energy plot shows the minimum value for 2π end twist. Therefore, the instrument tends to go for looping if the end twist is present. Force and torque characteristics are obtained which will lead to the design and control of these instruments. Force and torque plots show negative stiffness when the instrument is going for looping. The unlooping phenomenon is also discussed and a strategy is proposed to mitigate looping. The proposed modeling approach can be utilized to address the complex behavior of a flexible instrument in medical as well as in other industrial applications. The insight developed will help in designing and developing control for safe and reliable usage of flexible instruments in various domains.
New Reactor Safety Measures for the European Sodium Fast Reactor—Part I: Conceptual Design
Authors: Guidez Joel , Bodi Janos , Mikityuk Konstantin , Girardi Enrico , Carluec Bernard
Published: June 2021

Following up the previous collaborative project on European sodium fast reactor (CP-ESFR project), the European sodium fast reactor—safety measures assessment and research tools (ESFR-SMART project) considers the safety objectives envisaged for generation-IV reactors, taking into account the lessons learned from the Fukushima accident, in order to increase the ESFR safety level. In accordance with these objectives, guidelines have been defined to drive the ESFR-SMART developments, mainly simplifying the design and using all the positive features of sodium fast reactors (SFR), such as low coolant pressure, efficiency of natural convection, possibility of decay heat removal (DHR) by atmospheric air, high thermal inertia, and long grace period before a human intervention is needed. In this paper, a set of new ambitious safety measures is introduced for further evaluation within the project. The proposed set aims at consistency with the main lines of safety evolutions since the Fukushima accident. The paper gives a first review of the new propositions to enhance the ESFR safety, leading to a simplified reactor, forgiving and including a lot of passivity. This first version is supported by the various project tasks in order to assess the relevance of the whole design in comparison to the final safety objectives.
Research on Effect Factors of Mechanical Response of Cross-Fault Buried Gas Pipeline Based on Fluid–Structure Interaction
Authors: Li Qiaochu , He Sha
Published: June 2021

Long-distance buried pipelines inescapably go through seismic fracture zones which makes the buried pipelines be easily influenced by the diastrophism. A strong and resilient pipe can withstand a certain degree of seismic oscillation. However, it is really difficult for buried pipelines to resist the permanent ground displacement caused by faulting and surface damage. Most of the existing studies only focus on the two-phase contact between pipeline and soil, and the mechanical behavior of the cross-fault pipeline under transportation condition has not been studied. In this article, ADINA finite element software is used to establish a pipe-soil-fluid three-phase coupling model based on fluid–structure interaction (FSI), and the influence of the parameters of pipe, fluid and fault on the mechanical properties of cross-fault buried gas pipeline is studied. The model considering the effect of fluid–structure interaction can effectively simulate the mechanical response of pipelines in the actual working condition. The work presented in this article can provide a reference for the design and safety of cross-fault buried pipeline conveying fluid.
A Decision-Centric Framework for Modeling Evolutionary Complex Systems
Authors: Sha Zhenghui , Panchal Jitesh H.
Published: June 2021

The human society is facing new challenges, such as cyber-security, environmental safety, and energy sustainability, which cannot be solved by a single engineering product or system. When seeking ways to address the challenges in order to meet fundamental human needs, the solutions often lead to large-scale complex systems. In complex systems, there are large numbers of interactive entities that work together to form a system of value greater than the sum of the individuals.
Probabilistic Reasoning and Inconsistency Identification in Graph-based Models
Authors: Herzig Sebastian J. I. , Paredis Christiaan J. J.
Published: June 2021

In 1998, the National Aeronautics and Space Administration (NASA) launched the Mars Climate Orbiter (MCO) as part of the Mars Surveyor ’98 program. Upon arrival at Mars, MCO was to enter an elliptical orbit around the planet. On the day of orbit insertion, ground control was able to track the spacecraft visually up to the point when it vanished behind the planet. Unfortunately, the spacecraft never reappeared on the other side. It was later discovered that the probe came too close to the planet, and crashed into the Martian surface. The cause? A previously undiscovered mismatch in the use of unit systems for performing certain calculations in parts of the ground station software [43].
Learning and Tracking Ad Hoc Fiducial Markers in Spatial Augmented Reality
Authors: Gould Emma , Guerin Stephen , Smith Cody , Smith Steve , Bush Brian , Gruchalla Kenny
Published: June 2021

We describe a spatial augmented reality system with a tangible user interface used to control computer simulations of complex systems. In spatial augmented reality, the user’s physical space is augmented with projected imagery, blending real objects with projected information, and a tangible user interface enables users to manipulate physical objects as controllers for interactive visualizations. Our system learns ad hoc objects in the user’s environment as fiducial markers (i.e., objects that are visually recognized and tracked). When combined with simulation and visualization tools, these interfaces allow the user to control simulations or ensembles of simulations via physical objects using apt metaphors. While other research has leveraged the use of depth cameras, our system enables the use of standard cameras in readily available smartphones and webcams and has an implementation that runs completely in JavaScript in the web browser. We discuss the prerequisite object-recognition requirements for such tangible user interfaces and describe computer-vision and machine-learning algorithms meeting those requirements. We conclude by presenting example applications, which are also available online.
Automatic differentiation approach for acoustic holograms: Performance and potential applications
Authors: Fushimi Tatsuki , Yamamoto Kenta , Ochiai Yoichi
Published: June 2021

Acoustic holography underpins the number of modern acoustics applications. The usage of multi-focal acoustic holograms with phased array transducers (PATs) in ultrasonic tactile displays and acoustic levitation are increasing, and achieving a high-quality hologram are of significant interest. Inspired by the latest optical hologram optimizer, we developed a novel acoustic hologram optimizer for PATs called Diff-PAT [T. Fushimi, K. Yamamoto, and Y. Ochiai, “Acoustic hologram optimisation using automatic differentiation”]. Diff-PAT is based on a gradient-descent algorithm and automatic differentiation. The performance of Diff-PAT was numerically evaluated using three array configurations and it achieved superior accuracy over the conventional optimizers. For example, when two focal points are generated with 196 ultrasonic (40 kHz) transducers; the state of art optimizer (with phase and amplitude modulation) based on Eigensolver has an average error of 4.07 % where Diff-PAT (with only phase modulation) achieve average error of 0.0174%. These results show that amplitude and phase modulation may not be necessary for PATs to be successful. Furthermore, we demonstrate the versatility of Diff-PAT by applying it to binary acoustic holograms, simultaneous modulation of acoustic amplitude and phase at the target plane, and phase plates. [Work supported by Pixie Dust Technologies, Inc., Diff-PAT is patent pending (JP2020-167367A).]
Speech quality estimation with deep lattice networks
Authors: Chinen Michael , Skoglund Jan , Hines Andrew
Published: June 2021

Intrusive subjective speech quality estimation of mean opinion score (MOS) often involves mapping a raw similarity score extracted from differences between the clean and degraded utterance onto MOS with a fitted mapping function. More recent models such as support vector regression (SVR) or deep neural networks use multidimensional input, which allows for a more accurate prediction than one-dimensional (1-D) mappings but does not provide the monotonic property that is expected between similarity and quality. We investigate a multidimensional mapping function using deep lattice networks (DLNs) to provide monotonic constraints with input features provided by ViSQOL. The DLN improved the speech mapping to 0.24 mean-square error on a mixture of datasets that include voice over IP and codec degradations, outperforming the 1-D fitted functions and SVR as well as PESQ and POLQA. Additionally, we show that the DLN can be used to learn a quantile function that is well-calibrated and a useful measure of uncertainty. The quantile function provides an improved mapping of data driven similarity representations to human interpretable scales, such as quantile intervals for predictions instead of point estimates.
Heterogeneity of meningeal B cells reveals a lymphopoietic niche at the CNS borders
Authors: Brioschi Simone , Wang Wei-Le , Peng Vincent , Wang Meng , Shchukina Irina , Greenberg Zev J. , Bando Jennifer K. , Jaeger Natalia , Czepielewski Rafael S. , Swain Amanda , Mogilenko Denis A. , Beatty Wandy L. , Bayguinov Peter , Fitzpatrick James A. J. , Schuettpelz Laura G. , Fronick Catrina C. , Smirnov Igor , Kipnis Jonathan , Shapiro Virginia S. , Wu Gregory F. , Gilfillan Susan , Cella Marina , Artyomov Maxim N. , Kleinstein Steven H. , Colonna Marco
Published: June 2021

Getting around the blood–brain barrier

The meninges comprise three membranes that surround and protect the central nervous system (CNS). Recent studies have noted the existence of myeloid cells resident there, but little is known about their ontogeny and function, and whether other meningeal immune cell populations have important roles remains unclear (see the Perspective by Nguyen and Kubes). Cugurra
et al.
found in mice that a large proportion of continuously replenished myeloid cells in the dura mater are not blood derived, but rather transit from cranial bone marrow through specialized channels. In models of CNS injury and neuroinflammation, the authors demonstrated that these myeloid cells have an immunoregulatory phenotype compared with their more inflammatory blood-derived counterparts. Similarly, Brioschi
et al.
show that the meninges host B cells that are also derived from skull bone marrow, mature locally, and likely acquire a tolerogenic phenotype. They further found that the brains of aging mice are infiltrated by a second population of age-associated B cells, which come from the periphery and may differentiate into autoantibody-secreting plasma cells after encountering CNS antigens. Together, these two studies may inform future treatment of neurological diseases.

Science
, abf7844, abf9277, this issue p.
eabf7844
, p.
eabf9277
; see also abj8183, p.
396
Uncertain effects of the pandemic on respiratory viruses
Authors: Gomez Gabriela B. , Mahé Cedric , Chaves Sandra S.
Published: June 2021

Expanded genomic and clinical surveillance are needed to understand the spread of respiratory viruses
Serotypes of Enterotoxigenic
Escherichia coli
Isolated in the United States
Authors: DeBoy John M. , Wachsmuth I. Kaye , Davis Betty R.
Published: June 2021

Strains of enterotoxigenic
Escherichia coli
isolated from humans in the United States were found in 11 of 16 serotypes that previously were documented in the international literature as associated with enterotoxin production. Of 68 strains belonging to these 11 serotypes, 28 (41%) were enterotoxigenic; none of 46 strains belonging to 5 other previously implicated serotypes was enterotoxigenic. Control cultures of various serotypes were selected for comparison and found to contain 0 to 7% enterotoxigenic
E. coli. E. coli
belonging to documented enterotoxin-associated serotypes, characterized by both O and H antigens, were selected for toxin testing to determine their prevalence and potential pathogenicity in this country. In this study, a strain possessing any combination of an enterotoxin-associated serotype O antigen and H antigen was more likely to be enterotoxigenic than strains possessing only the specific O antigen or H antigen or neither. Five
E. coli
strains belonging to undocumented enterotoxin-associated serotypes did contain a combination of previously reported enterotoxin-associated serotype O and H antigens and did produce enterotoxin.
Cell-Mediated and Humoral Immunity to Herpesviruses During and After Herpes Zoster Infections
Authors: Sørensen Ole S. , Haahr Sven , Møller-Larsen Anné , Wildenhoff Kaj
Published: June 2021

The influence of herpes zoster virus infection on cell-mediated and humoral immunity to varicella-zoster virus (VZV), cytomegalovirus, and herpes simplex virus (HSV) was followed in 17 zoster patients from the first week to 6 months after start of eruptions. The clinical responses were registered and correlated to the immune responses. A significant depression in blast transformation on stimulation of lymphocytes with all three antigens was found on days 1 to 5 compared with transformations later after zoster eruptions and compared with controls. Phytohemagglutinin exhibited the same stimulation in the different groups and controls. No significant differences in interferon production in the various groups and controls were found on stimulation with the VZV and HSV antigens. All zoster patients became seropositive by complement fixation to VZV a few days after start of the zoster eruption. Two zoster patients showed a fourfold rise in complement fixation antibodies to HSV. Three patients had changes in complement fixation titers to cytomegalovirus, which could indicate new infection or reactivation of infection with this virus. A significant lower transformation index to VZV was found during the first 9 days in zoster patients with fever compared with patients without fever. The relevance of this observation is discussed in relation to a previous similar observation from our group.
Characterization of the adherence properties of Streptococcus salivarius
Authors: Weerkamp A H , McBride B C
Published: June 2021

The adherence and aggregation properties of 46 human oral Streptococcus salivarius isolates were examined. A total of 41% of the isolates aggregated with whole human saliva, 50% aggregated with human erythrocytes, and 85% adhered to human buccal epithelial cells. Strains that aggregated with saliva and erythrocytes usually reacted with Streptococcus group K typing serum whereas the non-hemagglutinating strains did not. K+ strains also adhered more strongly to human buccal epithelial cells than K- strains. All isolates coaggregated with Fusobacterium nucleatum LF and Bacteroides asaccharolyticus 2D, 91% coaggregated with Veillonella alcalescens V1, and 50% coaggregated with Veillonella parvula V4. S. salivarius HB aggregated with saliva from 15 different human donors and aggregated with human erythrocytes irrespective of the blood group. This strain only weakly aggregated with rat saliva or rat erythrocytes. We isolated mutants which concomitantly lost the ability to agglutinate erythrocytes, aggregate with saliva, and bind to buccal epithelial cells, but retained their interbacterial aggregation properties. A second class of mutants lost the ability to coaggregate with Veillonella, but these mutants retained all of the other aggregation properties. Treatment of S. salivarius HB cells with pronase or subtilisin destroyed their ability to aggregate with saliva and erythrocytes and to bind to buccal epithelial cells. The unique characteristics of the aggregation and adherence reactions were suggested by differences in the rate of loss of activity during protease treatment and in the response to chemical modification. The presence of saliva did not affect hemagglutination and adherence to buccal epithelial cells. Binding of the salivary aggregating factor to the bacteria could be distinguished from aggregation on the basis that the latter required divalent cations. The factor involved in coaggregation with F. nucleatum LF was physicochemically different from the other factors, since it was resistant to heat and to extraction with trichloroacetic acid, aqueous phenol, sodium dodecyl sulfate, and formamide, but was sensitive to proteases and was present in both classes of mutants. Coaggregation with V. alcalescens was not sensitive to proteases. A variety of mono- and disaccharides had no influence on any of the reactions tested.
Human immune interferon: induction in lymphoid cells by a calcium ionophore
Authors: Dianzani F , Monahan T M , Georgiades J , Alperin J B
Published: June 2021

Human lymphocyte cultures produced interferon after treatment with the calcium ionophore A23187, but not after treatment with potassium ionophore nonactin. Interferon production was detectable between 3 and 6 h after ionophore treatment and reached the maximum level between 12 and 24 h. Ionophore-induced interferon appeared to be immune interferon on the basis of acid lability, lack of neutralization by antibody to leukocyte interferon, slow kinetics of activation of the antiviral state, and molecular characterization by isoelectrofocusing.
Detection of Circulating Immune Complexes in the Sera of Rabbits with Experimental Syphilis: Possible Role in Immunoregulation
Authors: Baughn Robert E. , Tung Kenneth S. K. , Musher Daniel M.
Published: June 2021

The in vivo and in vitro immunoglobulin G plaque-forming cell responses to sheep erythrocytes (SRBC) are nearly obliterated during disseminated syphilitic infection (3 to 8 weeks post-intravenous injection) in rabbits. Splenic and lymph node cells obtained from infected rabbits during this time period were capable of suppressing the normal in vitro responses of uninfected, SRBC-primed cells. Cell-free washings of cells from infected animals were also suppressive. This finding coupled with the fact that treatment of infected cells with proteolytic enzymes abrogated the suppressive effect constitute arguments against involvement of a specific suppressor cell population. The incidence of elevated levels of circulating immune complexes in the sera of rabbits with disseminated disease was also significantly different from that of uninfected controls or infected rabbits before the onset or after the regression of lesions. When added to cultures of lymphocytes from uninfected, SRBC-sensitized rabbits, sera containing complexes caused dose-related suppression of the in vitro immunoglobulin responses. Unlike immune complexes, no correlation was found between the presence of mucopolysaccharide materials and the stage of infection or the ability of serum to suppress the immunoglobulin responses to SRBC.
Lipophilic derivative of muramyl dipeptide is more active than muramyl dipeptide in priming macrophages to release superoxide anion
Authors: Pabst M J , Cummings N P , Shiba T , Kusumoto S , Kotani S
Published: June 2021

Mouse peritoneal macrophages, when treated with a lipophilic derivative of muramyl dipeptide either in vitro or in vivo by intraperitoneal injection, showed a more than fivefold increase in their ability to generate superoxide anion after stimulation of the macrophages with phorbol myristate acetate. This response was more than twice that observed with the parent molecule, muramyl dipeptide (MDP). Unlike MDP, which has a systemic effect, the lipophilic derivative, [B30]-MDP, did not alter the response of peritoneal macrophages when given subcutaneously in the flank, suggesting that [B30]-MDP remains localized at the site of injection. The enhanced effect of [B30]-MDP over MDP appeared to be due to the inherent lipophilicity of the molecule, and was probably not due to either stimulation of T lymphocytes or activation of the alternative pathway of complement.
Class-specific antibody responses to Mycoplasma pulmonis in sera and lungs of infected and vaccinated mice
Authors: Taylor G , Howard C J
Published: June 2021

Class-specific antibodies were measured by a solid-phase microradioimmunoassay in the sera and lung washings of mice after intranasal or intravenous inoculation with live Mycoplasma pulmonis and after systemic, intranasal, or combined vaccination with Formalin-inactivated mycoplasmas. After intranasal or intravenous inoculation with live organisms, serum antibodies were first detected in immunoglobulin M (IgM) followed by IgG2, IgG1, and IgA classes, but significant levels of IgA developed only in those mice inoculated intranasally. The appearance of antibodies in lung washings was later than in serum, but again these were predominantly IgG2 and IgG1. After inoculation with killed organisms, serum antibodies were predominantly IgG1, although IgG2, IgM, and, in intranasally vaccinated mice, IgA were also present. Only IgG1 was detected in lung washings from mice vaccinated systemically, but IgA and IgG2 were present in addition in animals vaccinated intranasally. Immunofluorescence studies indicated that some antibody in lung washings from the latter group of animals was produced locally. A comparison of the levels of various class-specific antibodies and resistance to intranasal challenge suggested that local antibody of any immunoglobulin class is capable of mediating resistance in the lungs to M. pulmonis infection.
Chemical structure and inhalation toxicity of lipopolysaccharides from bacteria on cotton
Authors: Helander I , Salkinoja-Salonen M , Rylander R
Published: June 2021

Lipopolysaccharides from different bacteria isolated from cotton were purified and chemically analyzed. Their pulmonary toxicity to animals was tested in inhalation tests. Lipopolysaccharides from Agrobacterium and Xanthomonas were shown to differ from the others in that they contained no heptose and no non-hydroxylated fatty acids with a chain length of 12, 14, or 16 carbon atoms. Lipopolysaccharides from Pseudomonas putida, Enterobacter agglomerans, and Klebsiella oxytoca were found to cause an influx of polymorphonuclear leukocytes into the airways. Lipopolysaccharides from Agrobacterium sp. and Xanthomonas sinensis caused no significant invasion. The data point to substances in both the lipid A part and the core part of the lipopolysaccharides being responsible for the capacity to induce leukocyte invasion into the airways.
Attachment of Actinomyces naeslundii to human buccal epithelial cells
Authors: Saunders J M , Miller C H
Published: June 2021

A standardized assay was used to measure the attachment of Actinomyces naeslundii ATCC 12104 to washed human buccal epithelial cells. Treatment of the A. naeslundii cells with hyaluronidases, wheat germ lipase, protease, trypsin, heat, or sonic oscillation significantly reduced their ability to attach to epithelial cells. Treatment of the epithelial cells with the above enzymes did not influence the attachment of A. naeslundii. Extraction of A. naeslundii with NaOH also significantly reduced the ability of the bacterium to attach to human buccal epithelial cells. The neutralized and dialyzed NaOH extract contained both carbohydrate and protein substances in a ratio of about 1:1. Adding this extract back to the extracted bacterial cells partially restored their ability to attach to epithelial cells. When the NaOH extract was preincubated with epithelial cells and residual extract was removed by washing, attachment of normal A. naeslundii was partially blocked. The ability of the extracted material to block attachment was significantly reduced when treated with hyaluronidases or with wheat germ lipase. Treatment with heat, protease, or trypsin did not significantly reduce the ability of the extracted materials to block attachment. Pretreatment of the epithelial cells with hyaluronic acid or chondroitin sulfate also reduced subsequent attachment of normal A. naeslundii cells. Pretreatment of epithelial cells with dextrans, proteins, or unpure mannose did not influence subsequent attachment of A. naeslundii. Pretreatment of A. naeslundii with galactose and lactose significantly inhibited attachment to normal epithelial cells. The results suggest that the attachment of A. naeslundii to human buccal epithelial cells may involve mucopolysaccharides similar to hyaluronic acid on the surface of the bacterial cells. Other attachment mechanisms may also be operative.
Recognition of a new serogroup of Legionnaires disease bacterium
Authors: McKinney R M , Thomason B M , Harris P P , Thacker L , Lewallen K R , Wilkinson H W , Hebert G A , Moss C W
Published: June 2021

A strain of the Legionnaires disease bacterium (LDB) that was isolated by Joseph E. McDade from a postmortem lung specimen of a patient with fatal atypical pneumonia at the Veterans Administration Hospital in Togus, Maine was serologically different from 16 other strains of LDB that had been isolated previously from patients in other geographic locations. The serological differences of the Togus isolate were shown in results of direct and indirect fluorescent antibody staining and of immunoelectrophoresis with soluble antigen extracts. Seroconversion for the Togus strain of LDB in acute- and convalescent-phase sera from a second patient with atypical pneumonia at the Veterans Administration Hospital in Togus indicated that this patient had been infected with an LDB that was serologically similar or identical to the Togus isolate. The Togus serogroup of LDB should be considered when performing serological tests for Legionnaires disease.
Single-radial hemolysis as a cost-effective determinant of Rubella antibody status
Authors: Forger J M , Gilfillan R F
Published: June 2021

Single-radial hemolysis was examined for sensitivity, reliability, and cost for determination of rubella antibody levels in the general population. Results obtained with single-radial hemolysis plates made in this laboratory, and those under development by a commercial manufacturer, were compared with those obtained by the hemagglutination inhibition method normally used for rubella antibody determinations. The results suggest that single-radial hemolysis is comparable to hemagglutination inhibition with respect to sensitivity and reliability; it is superior to hemagglutination inhibition in terms of ease of manipulation and economy of use.
Serodiagnosis of viral hepatitis A by a modified competitive binding radioimmunoassay for immunoglobulin M anti-hepatitis A virus
Authors: Bradley D W , Fields H A , McCaustland K A , Maynard J E , Decker R H , Whittington R , Overby L R
Published: June 2021

A competitive binding radioimmunoassay (CBA) for antibody to hepatitis A virus (HAV) was evaluated and compared with a standard solid-phase radioimmunoassay for anti-HAV, CBA was found to be sensitive and specific for the detection of anti-HAV, as demonstrated by the 98% concordance of CBA and solid-phase radioimmunoassay test results. The standard CBA test was modified for the differential detection of acute (immunoglobulin M) and convalescent (immunoglobulin G) anti-HAV by incorporation of a step in which immunoglobulin G anti-HAV was preferentially absorbed with S. aureus cells (protein A). The modified CBA test was shown to be capable of differentiating between acute- and convalescent-phase sera. The modified CBAM test was able to detect immunoglobulin M anti-HAV up to approximately 4 weeks after the onset of illness.
Evaluation of blood culture procedures in a pediatric hospital
Authors: Szymczak E G , Barr J T , Durbin W A , Goldmann D A
Published: June 2021

To determine optimal clinical laboratory techniques for detecting pediatric bacteremia, we studied 7,768 consecutive blood cultures in a 1-year period. Blood was inoculated into one vented 50-ml bottle of brucella broth with 0.05% sodium polyanetholsulfonate and one unvented 50-ml bottle of Columbia broth with 0.05% sodium polyanetholsulfonate and 0.05% cysteine. Bottles were visually examined for growth on days 1 through 7 and blindly subcultured aerobically and anaerobically on days 1, 2, and 7. There were 724 (9.3%) positive cultures, and 484 (6.2%) were clinically significant. The most frequent isolates from bacteremic patients were Haemophilus influenzae (24%) and Streptococcus pneumoniae (17%). Growth was noted in only one bottle in 25% of clinically significant isolates. Bottles inoculated with greater than or equal to 1 ml of blood became positive earlier than bottles inoculated with less than 1 ml. After 1 day of incubation, 48% of the clinically significant cultures showed growth on visual examination, whereas 85% showed growth on subculture. Only 19% of Haemophilus isolates were detected visually on day 1, whereas 88% were recovered on subculture. By day 7, 3.5% of all isolates (including 18% of pneumococcal isolates and 1% of Haemophilus isolates) could no longer be recovered on subculture. We conclude that a two-bottle blood culture system and blind subculture within 24 h will optimize detection of pediatric bacteremia.
Comparison of four culture media for isolation of Mycobacterium avium complex from porcine tissues
Authors: Thoen C O , Himes E M , Jarnagin J L , Harrington R
Published: June 2021

The efficiency of four culture media was compared for the isolation of Mycobacterium avium complex from 197 procine tissues. In 82 tissues with microscopic granulomas and acid-fast bacilli, a significantly greater number of isolates were obtained on Middlebrook 7H10 medium with sodium pyruvate than on Stonebrink medium, Herrold egg yolk agar medium, or Lowenstein-Jensen medium (P=0.01). In 46 tissues in which no microscopic granulomas or acid-fast bacilli were observed, a significantly greater number of isolates were made on Middlebrook 7H10 medium or Herrold egg yolk agar medium than on Stonebrink medium or on Lowenstein-Jensen medium (P=0.01). The time required to grow M. avium complex on Lowenstein-Jensen medium was significantly greater than the time required to observe growth on Stonebrink, Middlebrook 7H10, or Herrold egg yolk agar medium (p=0.001).
Comparison of media and techniques for detection of group A streptococci in throat swab specimens
Authors: Dykstra M A , McLaughlin J C , Bartlett R C
Published: June 2021

Detection of group A streptococci in primary throat cultures was compared by using aerobic and anerobic incubation with selective nonselective media. Sheep blood agar plates incubated anaerobically detected 98% of the group A streptococci, whereas aerobically incubated blood agar plates which had been stabbed at the time of inoculation detected only 63%. Blood agar plates containing sulfamethoxazole and trimethoprim (23.75 and 1.25 mirograms per ml, respectively) detected only 70% of group A streptocci when incubated aerobically and 84% when incubated anaerobically.
Rapid subtyping of influenza A virus isolates by membrane fluorescence
Authors: Fishaut M , McIntosh K , Meiklejohn G
Published: June 2021

During the winter of 1977-1978 three influenza A virus serotypes (A/Vic/3/75, A/Texas/1/77 [both H3N2], and A/USSR/90/77 [H1N1]) circulated in Denver, offering us the opportunity to apply fluorescent antibody techniques to the specific identification of these viruses. Surface antigens of infected, unfixed primary monkey kidney cells were stained in suspension by an indirect immunofluorescence technique with anti-H3N2 and anti-H1N1 antisera. In tests of cells infected with known viruses, the members of the H3N2 family could not be distinguished from one another, but were easily distinguished from H1N1 strains. A total of 101 hemadsorption-positive clinical specimens were evaluated over a 6-month period. Forty-five of 48 influenza A H3N2 and 24 of 29 H1N1 specimens confirmed by hemagglutination inhibition were correctly identified by membrane fluorescence of cultured cells, with no misidentifications among influenza strains and with 1 false positive among 24 non-influenza isolates. The average time to identification by this technique was 4 days compared to 7 days by hemagglutination inhibition. Live cell membrane fluorescence is a simple, rapid, and accurate method for identifying and grouping influenza A viruses.
Thin-layer immunoassay for determination of antibodies to herpes simplex virus
Authors: Jeansson S , Elwing H , Nilsson L A
Published: June 2021

Thin-layer immunoassay (TIA) is a simple serological technique suitable for analysis of large numbers of samples. In this study, TIA was evaluated for determination of antibodies to herpes simplex virus. Herpes simplex virus antigen used in TIA was purified from material released from virus-infected cells. The results obtained by TIA were compared with those obtained by neutralization and complement fixation tests. TIA was found to be as sensitive as the neutralization test for demonstration of herpes simplex virus antibodies. No false-negative or -positive reactions were observed. In primary herpes simplex virus-1 infections, an antibody response was demonstrated by TIA, whereas antibodies could not be demonstrated in patients with primary herpes simplex virus-2 infections.