bluuebunny/crossref_metadata_2025 huggingface dataset:
The Affine Transformation for Orthotropic Plane-Stress and Plane-Strain Problems
Authors: Lang H. A.
Published: June 2021

It is demonstrated that a single affine transformation of the type x = ax′, y = by′ immediately extends the solution of any isotropic plane-stress or plane-strain problem to the solution of an orthotropic plane problem where the orthotropic material is characterized by three independent constants. Since orthotropy, defined as elastic symmetry with respect to two orthogonal axes, implies four independent elastic constants, the affine transformation introduces a restriction upon the orthotropic shear modulus. The orthotropic shear modulus differs from that used by previous investigators. This difference alters the equation which the orthotropic stress function must satisfy and, therefore, directly affects the solution to every plane-stress or plane-strain problem. Some arguments are advanced to favor the shear modulus, as here defined, whenever orthotropy must be restricted to three elastic constants. The two solutions of the orthotropic half plane subjected to a normal concentrated load are contrasted to illustrate the effect of the two definitions of orthotropic shear modulus.
The Stress Distribution in a Strip Loaded in Tension by Means of a Central Pin
Authors: Theocaris P. S.
Published: June 2021

It is the purpose of this paper to give an exact solution for the stress distribution resulting from loading a perforated strip in tension through a rigid pin filling the hole. The strip is regarded as of an infinite length and having a single axial hole. Stress distributions are found by an alternating approximation method and the stresses are tabulated in the form of stress-concentration factors for different values of diameter of the hole. The influence of size of the hole on the stress concentration in the strip is investigated and the optimum diameter of the hole is evaluated.
Unsteady Radial Flow of Gas Through Porous Media—Variable Viscosity and Compressibility
Authors: Aronofsky J. S. , Porter J. D.
Published: June 2021

Calculations of pressure-time histories and flow rates are presented for radial unsteady flow of gases through porous media. Some nonideal gas properties are considered by expressing gas viscosity and gas compressibility (z-factor) as simple functions of pressure. These calculations were obtained by using the high-speed, electronic computer called “Whirlwind” which is located at the Digital Computer Laboratory of the Massachusetts Institute of Technology. The results demonstrate that variable viscosity and compressibility can exert a substantial effect on transient gas-flow systems. A simple means is suggested for estimating the velocity of gas flowing across an inner radial boundary into a hole when the gas pressure is held constant at that boundary.
Buckling of Simply Supported Plates Tapered in Planform
Authors: Klein Bertram
Published: June 2021

Design curves are presented for determining the elastic buckling loads of simply supported flat plates of isosceles trapezoidal planform and loaded in compression along the parallel edges. Shear loads are assumed to act along the sloping edges so that any ratio of axial loads may act along the parallel edges of the given plate. Isosceles triangular plates are included as a special limiting case, and the range of the values of the various geometric and load parameters presented in the curves is considered large enough to cover practically all conditions of the type treated which are encountered in practice.
Creep Stresses and Deflections of Columns
Authors: Lin T. H.
Published: June 2021

A direct method (no iteration is involved) of calculating stresses and deflection of a pin-ended column with creep is shown. The relaxation moment in a particular time interval is treated as an additional initial curvature of the column. This method is applicable to stress-strain-time relationship obtained directly from test data without the necessity of making restrictive assumptions. An illustrative example is shown and the results are compared to those obtained by iteration method (10) and test data. Stress distributions across different sections at different instants are shown. The stress distribution at mid-section deviates considerably from being linear as the creep deflection becomes large.
Plastic Deformation of Semi-Infinite Beams Subject to Transverse Impact Loading at the Free End
Authors: Conroy M. F.
Published: June 2021

The object of this paper is to consider the plastic deformation of semi-infinite beams subject to dynamic transverse loading at the free end. The type of loading considered is that of a constant bending moment, together with a transverse force the magnitude of which is inversely proportional to the square root of time. Part 1 of the paper consists of a plastic-rigid analysis of the problem, based on the plastic-rigid analysis of infinite beams under transverse, constant velocity, impact loading developed by the author. Part 2 of the paper consists of an elastic-plastic solution of the problem, based on a theoretical analysis of the plastic deformation of infinite beams subject to transverse, constant-velocity impact loading developed by H. F. Bohnenblust. Specific problems are considered for which the deflection solutions obtained by elastic ideally plastic and rigid ideally plastic analyses are compared.
On the Wake Energy of Moving Cascades
Authors: Kemp N. H. , Sears W. R.
Published: June 2021

The rate of transfer of energy to the vortex-wake pattern is calculated for isolated thin airfoils and cascades of thin airfoils in unsteady flow. This part of the work parallels earlier investigations by Garrick (7) and Keller (1). Application is made to the elementary two-row stages treated in an investigation (2) of the induction effects due to relative motion of the blade rows. The results show that the energy transferred to the wake pattern is a small fraction of the work absorbed by the rotor. Cross-induced contributions for a two-row stage may be negative but are small. By far the greatest contribution to the wake energy is that due to the circulation fluctuations induced in a blade row by the relative motion of the adjacent downstream row.
Stress Functions for Rotating Plates
Authors: Hodge P. G.
Published: June 2021

The general theory of two-dimensional bodies subjected to body forces is well known. However, except for a few examples in which gravity is the body force, and various examples of rotationally symmetric rotating disks, comparatively little appears to have been done with this theory. The present paper applies the theory to the general case of a thin plate rotating about an axis in its plane. As specific examples, a circular plate rotating about a diameter, and a triangular plate rotating about a side are considered. For the case of a long thin triangle, the result is shown to reduce to that previously obtained by using an extension of beam theory.
Propagation of a Sudden Rotary Disturbance in an Elastic Plate in Plane Stress
Authors: Goodier J. N. , Jahsman W. E.
Published: June 2021

Detailed results are found for two plane-stress problems of an elastic plate with a hole from which a symmetrical disturbance is propagated. In the first a uniform shear stress is suddenly applied and maintained at the hole. In the second a uniform (rotary) velocity is suddenly applied and maintained. The subsequent motion is entirely rotary and involves shear stress only. The problems are mathematically analogous to those of symmetrical pressure and radial velocity at the hole, already solved by Kromm, and his analysis is followed. The existence of a similar analogy in the statical cases is well known.
Transient Temperature Rise in a Semi-Infinite Solid Due to a Uniform Disk Source
Authors: Atalla M. M. , Preston K.
Published: June 2021

A transient solution is presented for the temperature rise in a semi-infinite solid due to a circular-disk source with a uniform and constant rate of heat flux. The solution is obtained only along the axis of the disk. It is shown that the temperature-time relation at any point along this axis is obtainable from the corresponding well-known one-dimensional solution for a semi-infinite rod by the relation [ θ ( z , t ) ] 3-dimensional = [ θ ( z , t ) - θ ( z 2 + a 2 , t ) ] 1-dimensional where θ, z, a, and t are the temperature rise, distance from the surface, radius of the heat source, and time, respectively.
The Mean Stress Around a Small Opening of Any Shape in a Uniformly Loaded Plate
Authors: Brock J. S.
Published: June 2021

This paper proposes a theorem concerning the mean stress around an opening in a uniform stress field. The theorem states that the mean stress along the free boundary of an opening of any shape in a uniformly loaded plate is equal to the sum of the co-ordinate normal stresses applied to the plate at a great distance from the opening. The theorem is proved by using well-known properties of harmonic functions in conjunction with Green’s theorem.
Critical Thickness of Surface Film in Boundary Lubrication
Authors: Feng I-Ming , Chang C. M.
Published: June 2021

When the combined equivalent thickness of the surface film approaches and finally becomes greater than the critical value, the weakening of the interlocking effect of the plastic roughening results in rapid decrease in wear and ultimately reduces wear to practically zero. This is verified by experimental results of wear of pure metals with controlled surface film thickness in the region near the critical thickness.
The Bauschinger Effect on Columns
Authors: Paris P. C.
Published: June 2021

Earthquakes or the passing shock wave of an atomic blast may cause tensile yield in members before collapse in compression (1). In order to examine the effect of this reversal, the reduction of compressive properties of structural steel are analyzed after a variety of tensile pre-strains and these properties are applied to calculate collapse loads. The calculated maximum loads are then compared with test results to determine a practical method whereby they may be predicted.
On the Transmission of a Concentrated Load Into the Interior of an Elastic Body
Authors: Neidhardt G. L. , Sternberg Eli
Published: June 2021

An exact solution in series form is presented for the stresses and displacements in an elastic body bounded by one sheet of a two-sheeted hyperboloid of revolution, subjected to an axial concentrated load at the vertex. The problem is reduced to one governed by finite surface tractions with the aid of a scheme developed in (1), and the solution is based on the Boussinesq stress functions referred to spheroidal co-ordinates. The corresponding known solutions appropriate to the half space and to the circular cone are obtained as limiting cases. Numerical results are given for the normal stress on planes perpendicular to the axis of symmetry, at points on this axis. These values are utilized in a discussion aimed at the influence of the curvature of the boundary at the load point upon the transmission of the load into the interior of the body; the results indicate that this influence may be considerable.
The Boundary Layer Inside a Conical Surface Due to Swirl
Authors: Weber H. E.
Published: June 2021

An analysis of the axially symmetric boundary layer on the inside of a conical surface due to swirl flow about the conical axis is presented. The momentum integrals of the boundary layer are derived, and both the laminar and turbulent boundary-layer solutions are obtained numerically. In the free stream the flow is assumed to be a potential vortex. A comparison between theory and experiment is made by using the particle paths on the conical surface of a cyclone dust separator.
A Theory for Base Pressures in Transonic and Supersonic Flow
Authors: Korst H. H.
Published: June 2021

A physical flow model is devised based on the concepts of interaction between the dissipative shear flow and the adjacent free stream and the conservation of mass in the wake. Four flow components are integrated in the model; namely, the flow approaching the trailing edge, the expansion around the trailing edge, the mixing within the free-jet boundary, and the recompression at the end of the wake. A unique and stable solution results for the base pressure. Theoretical results obtained for thin approaching boundary layer do not require empirical information and are, therefore, best suited to evaluate the merits of the theory. Here emphasized is the case of isoenergetic constant-pressure mixing in the turbulent free-jet boundary and agreement is found between theory and experimental data.
The Influence of Blast Characteristics on the Final Deformation of Circular Cylindrical Shells
Authors: Hodge P. G.
Published: June 2021

The final maximum deformation of a reinforced circular cylindrical shell caused by a briefly applied, intense loading is considered. The maximum deformation is obtained in a form which requires a double quadrature of the pressure where the limits of the integration are determined from side conditions. Attempts are made to find a simple analytic approximation, but the attempts are unsuccessful for loads of practical importance. A straightforward graphical-numerical method of solution is devised. Several examples are considered in support of the conclusions. The shell is assumed to be infinitely long, so that end effects may be neglected. The load is assumed to be applied to the entire shell simultaneously. The shell is assumed a perfect cylinder, and the reinforcements are taken as rigid. Finally, the shell is assumed to be made of an ideal rigid-plastic material which satisfies a certain simplified yield condition and the associated flow rule.
Approximate Energy and Equilibrium Equations for Cylindrical Shells
Authors: Kennard E. H.
Published: June 2021

In a recent paper (1) additional results were reported for cylindrical shells of uniform thickness h, obtained by the method of systematic expansion in powers of h (2, 3). The expressions thus obtained are so lengthy, however, that their chief practical value seems to lie in checking the precision of simpler approximate expressions.
Interferon immunosuppression: mediation by a suppressor factor
Authors: Johnson H M , Blalock J E
Published: June 2021

Suppression of the in vitro antibody response to sheep erythrocytes by mouse fibroblast interferon occurred by induction of suppressor cell activity in spleen cells. The suppressor cells produced a soluble factor which mediated the immunosuppression. The suppressor factor did not inhibit virus replication; thus, interferon probably regulates the B-cell response by a mechanism that is different from its antiviral effect.
Transfer of interferon-induced viral resistance from human leukocytes to other cell types
Authors: Blalock J E , Weigent D A , Langford M P , Stanton G J
Published: June 2021

Nonsensitized human leukocytes cocultured with various xenogeneic epithelioid and fibroblastic cells produced human leukocyte interferon and shortly thereafter transferred antiviral activity to the xenogeneic cells. Antiviral activity in the cocultured xenogeneic cells was not due to cell-mediated cytotoxicity as measured by specific 51Cr release and staining with vital dyes. The transfer of antiviral activity from leukocytes to xenogeneic cells was blocked by rabbit antiserum to human leukocyte interferon. Transferred viral resistance failed to develop in actinomycin D-treated xenogeneic cells, even though these cells induced human leukocyte interferon. Based on these findings, it appears that interferon made in the cocultures acts on the leukocytes to effect the transfer of interferon-induced viral resistance to the xenogenic cells, possibly by transmission of an inducer for the antiviral state. These studies strongly suggest a new and efficient host defense against virus infection which does not require killing of noninfected or recently infected cells.
Evidence that botulinum C2 toxin has two dissimilar components
Authors: Iwasaki M , Ohishi I , Sakaguchi G
Published: June 2021

Botulinum C2 toxin produced by most toxigenic and nontoxigenic strains of Clostridium botulinum types C and D contains two distinct protein components, and these were separated by ion-exchange chromatography and gel filtration. Neither of these components manifested the original toxicity, but the original toxicity was restored when the two components were mixed together and trypsinized. This indicates that C2 toxin consists of two dissimilar protein components and that the cooperation of the two is required to elicit toxicity.
Optimized assay for thymidine kinase and its application to the detection of antibodies against herpes simplex virus type 1- and 2-induced thymidine kinase
Authors: Gronowitz J S , Källander C F
Published: June 2021

An optimized assay for herpes simplex virus type 1- and 2-induced deoxythymidine kinase (dTk) is described which used [125I]iododeoxyuridine (IUdr) as a substrate. Values for Km and Vsat were determined for both viral and cellular dTK, using either deoxythymidine or IUdR as a substrate. A comparison between the two substrates revealed that higher reaction velocities and lower Km values were obtained with IUdR. A standard assay was designed which uses 10(-7) M IUdR as a substrate. This assay can detect herpes simplex-induced dTK from as few as two infected cells and is several orders of magnitude more sensitive than conventional dTK assays which use 10(-5) M dT as a substrate. An easily detectable blocking activity, which was shown to be mainly confined to the immunoglobulin G antibody class, was found in most human sera which were positive for complement-fixing antibody against herpes simplex virus.
Anti-deoxyribonucleic acid antibody associated with persistent infection of mink with Aleutian disease virus
Authors: Hahn E C , Kenyon A J
Published: June 2021

Anti-deoxyribonucleic acid (DNA) antibody was quantitated in sera from mink infected with Aleutian disease virus (ADV). During the course of the disease after experimental infection, the amount of anti-DNA antibody increased 60% initially, but then decreased to an intermediate level when measured 2.5 months later. The percentage of serum immunoglobulin, however, steadily increased over 3.5-fold during this period, resulting in the characteristic gammopathy. Correlation between the level of anti-DNA antibody and hypergammaglobulinemia was demonstrated with sera from chronically infected mink. Competition experiments and use of labeled nucleic acids indicated that the immunoactivity was more specific for double-stranded DNA than single-stranded DNA or ribonucleic acid. Anti-DNA antibody was found in purified immunoglobulin from chronically infected mink. Differences in avidity of antibody to DNA among antisera that had the same equivalence point were found. Avidity of antibody for DNA increased during the course of the disease.
Genetic Control of Susceptibility to
Cryptococcus neoformans
in Mice
Authors: Rhodes Judith C. , Wicker Linda S. , Urba Walter J.
Published: June 2021

Inbred mice injected intravenously with 5 × 10
6
cells of
Cryptococcus neoformans
showed two patterns of survival: sensitive (A/WySn, A.BY, A/J, DBA/2J, NZB/B1NJ, and SWR/J) and resistant [C57BL/10Sn, B10.A, B10.A (2R), B10.S (7R),C57BR/cdJ, C58/J, C3H/HeJ, BALB/c, DBA/1J, and SJL/J]. Relative susceptibility based on survival time was shown to correspond to differences obtained for 50% lethal dose values. Either decreasing the dose of organisms or changing to the intraperitoneal route of inoculation resulted in prolonged survival times, but neither change affected the observed patterns of survival. F1 hybrids between different sensitive strains were also sensitive, whereas F1 hybrids between sensitive and resistant strains were resistant, indicating a dominant mode of inheritance. Sensitivity and resistance were shown to be under single gene control by segregation analysis in F2 progeny produced by inbreeding (B10.A × A/WySn)F1 hybrids and in (F1 × A/WySn) backcross progeny. Blood obtained from parental strains, F1, F2, and backcross hybrids was tested for the presence or absence of hemolytic complement. Mice lacking hemolytic complement activity in their sera are homozygous for the
Hc
0
allele at the
Hc
locus on chromosome 2 and are deficient in the complement component C5. A 1:1 correspondence was found between C5 deficiency and sensitivity to
C. neoformans.
Resistance was shown to cosegregate with the presence of hemolytic complement in the F2 and the backcross progenies.
Effect of environment on sensitivity of Neisseria gonorrhoeae to Pseudomonas aeruginosa bacteriocins
Authors: Stein D C , Hebeler B H , Young F E
Published: June 2021

The effect of environmental variation on the susceptibility of Neisseria gonorrhoeae to pyocin produced by Pseudomonas aeruginosa was examined. Susceptibility to at least one pyocin was demonstrated in strains of N. gonorrhoeae (99%), N. meningitidis (35%), and N. lactamica (47%). The degree of sensitivity to pyocin displayed by N. gonorrhoeae was affected by varying the pH of the growth environment. Gonococcal strains were more sensitive to growth inhibition by pyocins at an alkaline pH and less sensitive to growth inhibition at an acid pH. Inhibitory titers fluctuated during nonselective subculture of fresh clinical isolates. There was no apparent correlation between auxotype and sensitivity to pyocin. Also, no relationship between colony morphology and pyocin sensitivity was seen.
Antigenic Studies of Oral and Nonoral Black-Pigmented
Bacteroides
Strains
Authors: Reed Michael J. , Slots Jørgen , Mouton Christian , Genco Robert J.
Published: June 2021

Antigens of several oral and nonoral strains of
Bacteroides asaccharolyticus
(proposed classification of oral
B. asaccharolyticus, Bacteroides gingivalis
),
Bacteroides melaninogenicus
subsp.
intermedius, B. melaninogenicus
subsp.
melaninogenicus
, and
B. melaninogenicus
subsp.
levii
were identified in soluble preparations obtained by sonication, autoclaving, and NaOH treatment of whole bacterial cells. The sonicate preparations contained the most complete representation of soluble antigens using antisera to the whole organism in gel precipitation tests. Among strains of
B. melaninogenicus
subsp.
intermedius
many common antigens were detected, and no consistent antigenic differences were seen between strains from oral and nonoral sites. None of the antigens of
B. melaninogenicus
subsp.
intermedius
reacted with sera raised to several strains of oral or nonoral
B. asaccharolyticus
, nor did antigens prepared from the latter strains react with antisera to
B. melaninogenicus
subsp.
intermedius.
At least one common antigen was shared by strains of
B. melaninogenicus
subsp.
intermedius
and strains of
B. melaninogenicus
subsp.
melaninogenicus
; however, subspecies-specific antigens were also found. Antigens from and antisera to oral and nonoral strains of
B. asaccharolyticus
did not react with sera to and antigens from
B. melaninogenicus
subsp.
melaninogenicus.
Strains of
B. asaccharolyticus
isolated from the oral cavity were antigenically distinct from strains of
B. asaccharolyticus
obtained from nonoral sites and lesions. This lack of cross-reactivity between the oral and nonoral strains of
B. asaccharolyticus
together with recent findings of marked genetic differences between oral and nonoral strains of
B. asaccharolyticus
suggest that these groups of organisms may represent different species.
Characterization of pili associated with Escherichia coli O18ac
Authors: Wevers P , Picken R , Schmidt G , Jann B , Jann K , Golecki J R , Kist M
Published: June 2021

A strain of Escherichia coli O18ac isolated from the stool sample of a patient with diarrhea was found to agglutinate human erythrocytes. From the results presented it is suggested that this hemagglutination is mediated by pili. Isolated pilus preparations agglutinated human erythrocytes, whereas pilus-negative mutants did not. The serological and chemical analyses indicate that the pili associated with E. coli O18ac are distinct from other types found with E. coli.
Immunobiology of Germfree Mice Infected with
Nocardia asteroides
Authors: Beaman Blaine L. , Gershwin M. Eric , Scates Steven S. , Ohsugi Yoshiyuki
Published: June 2021

Nocardia asteroides
GUH-2 was administered either intranasally or by intravenous inoculation into (i) conventionally grown, (ii) germfree, and (iii) lipopolysaccharide-treated germfree NIH:S mice. The number of bacteria within the lungs, brain, kidneys, adrenals, liver, spleen, and blood was quantitated at 3, 24, 72, and 168 h after infection. Further, the histological changes that occurred in each of these organs after infection were studied. The data demonstrated that germfree mice were significantly more susceptible to the acute phase of infection caused by
N. asteroides
than the conventionally grown animals. The brains and lungs of these mice were affected most dramatically. Pretreatment of the germfree mice with lipopolysaccharide completely reversed this enhanced susceptibility and rendered the animals more resistant to infection than the conventionally grown mice. These observations establish further the role of macrophage activation and the development of cell-mediated immunity in host resistance to nocardia. In addition, the presence of a resident microflora within the host appears to be important in the development of resistance to systemic nocardial infections.
Lipoteichoic Acid-Binding and Biological Properties of T Protein of Group A
Streptococcus
Authors: Johnson Rudolph H. , Simpson W. Andrew , Dale James B. , Ofek Itzhak , Beachey Edwin H.
Published: June 2021

T protein was extracted with trypsin from an avirulent, M protein-deficient, type 1 group A
Streptococcus
and purified by ammonium sulfate precipitation and anion-exchange chromatography. The latter procedure removed contaminating lipoteichoic acid (LTA) from the T protein, which consisted of a heterogeneous mixture of polypeptides resistant to digestion by trypsin and ranged in molecular size from 160,000 to 200,000 daltons. Threonine, aspartic acid, glutamic acid, lysine, and valine were the most predominant amino acids. The binding of LTA to an affinity column of T protein was reversible with increasing concentrations of ethanol but not with increasing ionic strength. T protein bound less palmitic acid and LTA than did fatty acid-free bovine albumin and did not stimulate human peripheral lymphocytes. Because the surface and cell wall distribution of the T proteins and LTA appear similar, the possibility exists that T proteins and LTA may interact in situ by weakly hydrophobic bonds. Such ligand-ligand interaction may be indirectly involved in the adherence of group A streptococci to host cell membranes that is known to be mediated by LTA.
Immunization of suckling pigs against enterotoxigenic Escherichia coli-induced diarrheal disease by vaccinating dams with purified K99 or 987P pili: antibody production in response to vaccination
Authors: Isaacson R E , Dean E A , Morgan R L , Moon H W
Published: June 2021

Pilus-specific antibody levels measured by enzyme-linked immunosorbent assays in serum and colostrum of pregnant swine (dams) were shown to increase after parenteral vaccination with pili. Pilus-specific antibody levels in dams were correlated with protection of their suckling offspring against fatal diarrhea caused by enterotoxigenic Escherichia coli possessing the same pilus as the vaccine.
Leukemogenesis, immune responsiveness, and murine leukemia virus expression in congenic AKR/J mice differing at H-2
Authors: Johnson D A , Bedigian H G , Cherry M , Meier H
Published: June 2021

In this study we examined the leukemia incidence, ectropic and xenotropic murine leukemia virus expression, and immune responsiveness of congenic AKR/J mice differing at the H locus. Congenic AKR.L-H-2b/1 mice, bearing the H-2b haplotype derived from C57L/J, were found to have a significant delay in time of death due to leukemia relative to that of AKR/J (H-2k) mice. The expression of ecotropic murine leukemia virus was found to be identical in both strains. The expression of xenotropic murine leukemia virus did vary, however, with the AKR.L-H-2b/1 mice showing a significantly reduced level of virus expression relative to AKR/J mice. In addition to these observations, we found that the AKR.L-H-2b/1 mice have an enhanced blastogenic responsiveness to phytohemagglutinin and to specific antigen to which they had previously been sensitized. Concomitant enhanced antibody response was not found. We suggest that the stronger cellular response, relative to AKR/J, may contribute to the delay in leukemia onset and to reduced xenotropic virus expression observed with the congenic mice.
Antivirus antibody-dependent cell-mediated cytotoxicity during murine cytomegalovirus infection
Authors: Manischewitz J E , Quinnan G V
Published: June 2021

BALB/c mice infected with murine cytomegalovirus were studied to determine whether antibody-dependent cell-mediated cytotoxicity contributes to the immune control of this infection. Antibody-dependent killer cells from uninfected mice were used as effector cells to assay for antibody in sera of infected mice. Secondary immune sera were found to contain both cytomegalovirus-specific and autoreactive antibodies. After primary infection only cytomegalovirus-specific antibodies were found. These were detected by antibody-dependent cell-mediated cytotoxicity within 8 to 10 days after onset of infection, but usually not until day 21, by a neutralizing antibody assay. Antibody titers were about 10-fold higher by antibody-dependent cell-mediated cytotoxicity than by neutralization. The results indicate that cellular immunity to cytomegalovirus infection includes an antibody-dependent cell-mediated cytotoxicity response which is likely to be highly efficient and may contribute significantly to control of both acute and later stages of infection.
Effects of cigarette smoke and its constituents on the adherence of polymorphonuclear leukocytes
Authors: Bridges R B , Hsieh L , Haack D G
Published: June 2021

The in vitro effects of the water-soluble fraction of whole cigarette smoke (WSF) and two alpha, beta-unsaturated aldehydes of cigarette smoke (acrolein and crotonaldehyde) on polymorphonuclear leukocyte (PMNL) adherence were determined with nylon fiber columns. Each of these cigarette smoke constituents caused a dose-dependent inhibition of PMNL adherence. However, at least fivefold higher concentrations of these agents were necessary to inhibit adherence as compared with those necessary to achieve the same level of inhibition of PMNL chemotaxis. Furthermore, inhibition of adherence by WSF could be differentiated from its effects on chemotaxis in that reduced glutathione completely protected chemotaxis from the effects of WSF but only afforded partial protection to PMNL adherence. These data suggest that the inhibitory effects of WSF, acrolein, and crotonaldehyde on PMNL chemotaxis are not due to their inhibition of adherence. Finally, although PMNL adherence is considered to be an integral part of the chemotactic mechanism, differentiation between these two PMNL functions may be possible, since some inhibitors of chemotaxis do not have corresponding inhibitory effects on adherence.
Stimulation of activated rat T cells in vitro by Listeria monocytogenes antigens
Authors: Woan M C , Forsum U K , McGregor D D
Published: June 2021

A soluble extract of Listeria monocytogenes bound firmly and in similar amounts to a variety of rat cells. Cells that bound this material differed in their capacity to stimulate the in vitro proliferation of lymphocytes obtained from the thoracic duct of Listeria-immune donors. The capacity of cells to serve as antigen-presenting cells in this system coincided or closely overlapped the expression on these cells of an Ia antigen-like structure. Three lines of evidence indicate that T cells respond to L. monocytogenes antigen: the responder cells are members of a nylon-wool nonadherent population that lacks readily detectable surface immunoglobulin; they express determinants recognized by the W3/25 monoclonal antibody (a surface marker of rat peripheral T cells); and they are stimulated optimally by L. monocytogenes antigen when the latter is displayed on cells that share a haplotype with the responder lymphocytes.
Ciliostatic, hemagglutinating, and proteolytic activities in a cell extract of Mycoplasma pneumoniae
Authors: Chandler D K , Barile M F
Published: June 2021

An extract of Mycoplasma pneumoniae, prepared from glass-grown organisms by extraction with 2 M NaCl, followed by freeze-thaw, ultracentrifugation, dialysis, and lyophilization, yielded approximately 20% of the total mycoplasmal protein. The extract contained at least 20 protein bands on sodium dodecyl sulfate-polyacrylamide gels and 2 to 5% carbohydrate and inhibited 70 to 100% of the ciliary activity of hamster tracheal organ cultures (ciliostasis). The extent of ciliostasis was dependent on the concentration of the extract. The extract also produced hemagglutination of human O-positive erythrocytes and showed proteolytic activity with a synthetic tetrapeptide substrate, S-2222. These in vitro tissue-damaging activities may be associated with the virulence of the mycoplasmas and with the pathogenesis of M. pneumoniae disease.
Immune Response in Rabbits to Surface Components of Extracellular and Intracellular Forms of Vaccinia Virus
Authors: Balachandran N. , Seth P. , Mohapatra L. N.
Published: June 2021

The development of cellular as well as humoral immune response to extracellular and intracellular forms of vaccinia virus (ECV and ICV, respectively) and their surface antigens were studied in rabbits. Direct lymphocyte cytotoxicity and peripheral blood leukocyte migration inhibition tests were used to measure cell-mediated immune response, while neutralizing and hemagglutination-inhibiting antibodies were assayed for measuring humoral immune response. Direct cytotoxicity of lymphocytes from rabbits immunized with ECV or its surface proteins was demonstrable by day 7 after immunization, and by the end of week 3 it almost declined to pre-immunization levels. Inoculation with ICV or its surface proteins failed to induce lymphocyte cytotoxicity. In contrast, migration inhibition of peripheral blood leukocytes from rabbits immunized with ECV, ICV, or their surface proteins was observed with homologous antigens. However, leukocytes from rabbits immunized with ECV or its surface proteins also showed migration inhibition in the presence of ICV. Similarly, in the humoral immune response, neutralizing antibodies were produced against homologous as well as heterologous forms of virus despite immunization with purified preparations of ECV, ICV, or their surface proteins. Adsorption with purified ICV preparations abolished the neutralizing activity of these antisera against heterologous forms of virus. Hemagglutination-inhibiting antibodies, on the other hand, were produced only after immunization with ECV or its surface proteins. In addition, antibody-dependent cell-mediated cytotoxicity was employed to detect specific antibody response after immunization of rabbits with live virus, ECV, and ICV. Antisera raised against ECV or live virus supported antibody-dependent cell-mediated cytotoxicity, whereas ICV-antiserum failed to do so. The antibody activity present in the former antisera was abolished by absorption with cell membranes from vaccinia-infected cells but not with purified ICV. The data suggest that immunization with inactivated ECV seems to bring about interaction between host immune response (cellular and humoral) and virus-infected cells, which may, perhaps, be necessary for protection against pox virus infection. A similar interaction is unlikely to occur after immunization with inactivated ICV.
Effect of fusidic acid on the immune response in mice
Authors: Bellahsène A , Forsgren A
Published: June 2021

The effect of fusidic acid on the immune response in mice was studied. At the nontoxic dose of 500 mg/kg per day, the cell-mediated immunity was strongly inhibited. A marked and significant prolonged survival of split-heart allografts in treated animals was detected. The survival time of allografts in mice receiving fusidic acid from the day of the transplantation until the grafts were rejected was 26.1 days compared with 14.5 days in untreated animals. In mice treated also before the transplantation, the mean survival of the allografts were even longer. The phytohemagglutinin response, as well as the mixed lymphocyte culture stimulation of spleen lymphocytes from mice given 500 mg of fusidic acid per kg daily for 1 week, were significantly inhibited. At the same dose there was also a significantly decreased primary antibody response to sheep erythrocytes, but it was of limited biological significance. The immunosuppressive effect in animals treated with a human therapeutic dose of fusidic acid (25 mg/kg per day) was less pronounced but significant. The relevance of these results is discussed.
Humoral immune response of rabbits to acholeplasmal lipoglycans
Authors: Lynn R J , Guidici P A , Hollemweguer E J , Smith P F
Published: June 2021

Lipoglycans extracted from Acholeplasma species with hot aqueous phenol were immunogenic for rabbits when introduced by an appropriate method. All lipoglycans examined elicited antibody associated with a heavy, 2-mercaptoethanol-sensitive immunoglobulin fraction when inoculated intravenously adsorbed to autologous rabbit erythrocytes. This antibody was specific for the Acholeplasma species from which the lipoglycan was extracted. Extensive immunization of these animals with acholeplasmal lipoglycans produced significant increases in sheep erythrocyte hemolysin. Some, but not all, Acholeplasma species yielded lipoglycans that were immunogenic when emulsified with Freund complete adjuvant and introduced via the footpad into rabbits. Such animals produced antibodies corresponding to the M and G immunoglobulin classes that reacted with both homologous and heterologous acholeplasmal lipoglycans by precipitation in immunodiffusion as well as passive hemagglutination. None of the animals inoculated demonstrated a significant anamnestic response after booster injections either intravenously or via the footpads.
Further Studies of the Neuraminidase Content of Inactivated Influenza Vaccines and the Neuraminidase Antibody Responses After Vaccination of Immunologically Primed and Unprimed Populations
Authors: Kendal Alan P. , Bozeman F. Marilyn , Ennis Francis A.
Published: June 2021

Purified concentrates of influenza A/USSR/90/77(H1N1)-like, A/Texas/1/77 (H3N2)-like, and B/Hong Kong/5/72-like viruses used for preparation of investigational and licensed vaccines in 1978 to 1979 were tested for their content of neuraminidase enzyme activity. Concentrates of H1N1 virus used to prepare vaccines for clinical investigations performed in the spring of 1978 had neuraminidase activity at that time which decreased during storage to almost undetectable levels (three lots) or by 50% (one lot) by the winter of 1978. Several other lots of concentrates prepared with H1N1 virus and used for vaccine formulation had no detectable neuraminidase enzyme activity when tested in the winter of 1978, at a time when they would be administered in vaccines. The range of specific activity for different lots of concentrates was about 40-fold for A/Texas/1/77, B/Hong Kong/5/72, and A/USSR/90/77 neuraminidases. Immunogenicity of investigational vaccines prepared with tested concentrates and administered between April and July 1978 was measured in volunteers aged 13 to >50 years. Frequency of neuraminidase antibody rises to two doses of H1N1-containing vaccine was 10% in unprimed subjects aged <26 years and about 18 to 36% in older persons. The frequency of neuraminidase antibody rises to one dose of H3N2-containing vaccine varied from 0 to 32% in different groups (mean, 18%). The frequencies of neuraminidase antibody responses were always much lower than the frequencies of hemagglutinin antibody responses. These observations confirm the existence of practical difficulties in achieving uniformity of the neuraminidase content in influenza vaccines and of ensuring good immunogenicity of vaccine neuraminidase even in primed populations.
Endotoxin-Like Activities of Mycoplasmal Lipopolysaccharides (Lipoglycans)
Authors: Seid Robert C. , Smith Paul F. , Guevarra Gabriel , Hochstein H. Donald , Barile Michael F.
Published: June 2021

Lipoglycans (previously designated lipopolysaccharides) from several species of
Acholeplasma
and from
Thermoplasma acidophilum
were examined for endotoxin-like activities as measured by the standard rabbit fever test and the
Limulus
amoebocyte lysate assay. The lipoglycans from
Acholeplasma granularum, Achloplasma laidlawii, Acholeplasma modicum
, and
Acholeplasma oculi
caused a febrile response at concentrations of 1 ng/ml per kg or greater, whereas with control
Escherichia coli
EC-2 lipopolysaccharides, 6.25 ng/ml per kg was required. Similar results were obtained in the
Limulus
amoebocyte lysate test. The minimum concentrations in nanograms per milliliter required to stimulate formation of a solid clot were:
Acholeplasma axanthum
, 0.22;
A. granularum
, 0.85;
A. modicum
, 0.51;
A. laidlawii
, 1.05;
A. oculi
, 0.74. Standard
E. coli
1B lipopolysaccharide required a concentration of 0.125 ng/ml.
Thermoplasma
lipoglycan was least active, requiring 4.25 ng/ml. Clotting of the
Limulus
lysate proceeds by the activation by lipopolysaccharide plus Ca
2+
of a proenzyme which cleaves an arginine-lysine peptide bond of the coagulogen. The clotting and amidase activities are inactivated by deoxycholate and can be reactivated by addition of lipopolysaccharide and Ca
2+
. As with
E. coli
1B lipopolysaccharide, acholeplasmal lipoglycans were shown to restore both clotting and amidase activities of the deoxycholate-inactivated
Limulus
clotting enzyme. The degree of restoration of amidase activity by mycoplasmal lipoglycans relative to
E. coli
lipopolysaccharide (1.00) were:
A. axanthum
, 1.71;
A. modicum
, 1.22;
A. granularum
, 0.61; and
Thermoplasma
, 0.37. The coagulating enzyme, restored with either
E. coli
lipopolysaccharide or mycoplasmal lipoglycans, was able to react with the synthetic peptide benzoyl-Ile-Glu-(γ-OCH
3
)-Gly-p-nitroaniline (an analog of the coagulogen) or with the purified coagulogen itself to form the clot. The mycoplasmal lipoglycans alone were incapable of promoting these reactions when incubated with the synthetic peptide or with the purified coagulogen, thereby ruling out the contamination of these lipoglycans with proteases capable of cleaving the same Arg-Lys peptide bond of the coagulogen. These results show that acholeplasmal lipoglycans possess endotoxin-like activities. Their passive or active role in disease remains to be established.
Segregation and rearrangement of coamplified genes in different lineages of mutant cells that overproduce adenylate deaminase
Authors: Debatisse M , Hyrien O , Petit-Koskas E , de Saint-Vincent B R , Buttin G
Published: June 2021

Four genes encoding proteins designated as W, X, Y1, and Y2 were found previously to be amplified at different levels in a Chinese hamster fibroblast mutant line selected for overproduction of adenylate deaminase. To gain information on the molecular mechanisms responsible, we studied the levels of amplification and the structures of these four genes in several lineages of mutant cells with comparable activities of adenylate deaminase, the selected enzyme. Only the W gene was amplified in all the lines. In one line, the X, Y1, and Y2 genes were coamplified, while in others either the Y1 gene or the pair X and Y2 were coamplified. The results were consistent with linkage of all the genes--in a particular order--in an amplifiable sequence with variable endpoints. Novel joints with a nonrandom distribution were observed. We frequently detected rearranged copies of the W gene, but very few novel joints were present in the other three genes in the six highly amplified lines examined. Some of the novel joints in gene W were highly amplified; they were generated by reamplification of a rearrangement that appeared at an early selection step. In some lines, reamplification was accompanied by deletion or mass correction of preexisting units. We discuss mechanisms which might account for these observations.
Problem-Solving Skills Among Precollege Students in Clinical Immunology and Microbiology: Classifying Strategies with a Rubric and Artificial Neural Network Technology
Authors: KANOWITH-KLEIN SUSAN , STAVE MEL , STEVENS RON , CASILLAS ADRIAN M.
Published: June 2021

Educators emphasize the importance of problem solving that enables students to apply current knowledge and understanding in new ways to previously unencountered situations. Yet few methods are available to visualize and then assess such skills in a rapid and efficient way. Using a software system that can generate a picture (i.e., map) of students’ strategies in solving problems, we investigated methods to classify problem-solving strategies of high school students who were studying infectious and noninfectious diseases. Using maps that indicated items students accessed to solve a software simulation as well as the sequence in which items were accessed, we developed a rubric to score the quality of the student performances and also applied artificial neural network technology to cluster student performances into groups of related strategies. Furthermore, we established that a relationship existed between the rubric and neural network results, suggesting that the quality of a problem-solving strategy could be predicted from the cluster of performances in which it was assigned by the network. Using artificial neural networks to assess students’ problem-solving strategies has the potential to permit the investigation of the problem-solving performances of hundreds of students at a time and provide teachers with a valuable intervention tool capable of identifying content areas in which students have specific misunderstandings, gaps in learning, or misconceptions.
Draft Genome Sequences of Two Xanthomonas fragariae Strains
Authors: Herbert Austin , Wang Hehe , Saski Christopher , Turechek William
Published: June 2021

Xanthomonas fragariae
is the causal agent of angular leaf spot of strawberry. Short-read sequences were generated for two
X. fragariae
strains with different virulence phenotypes on the Illumina HiSeq 2000 platform. The genome sequences will contribute to a better understanding of pathogen evolution and the genes contributing to virulence in
X. fragariae
.
Complete Genome Sequence of Bacillus safensis Strain 3A, a Heavy Metal-Resistant Bacterium Isolated from Contaminated Estuarine Sediment in Brazil
Authors: Defalco Thaiane , Vasconcelos Ana L. S. , Dias Armando C. F. , Barrientos Leticia , Bernardino Ângelo F. , Andreote Fernando Dini , Núñez-Montero Kattia
Published: June 2021

Bacillus safensis
3A was isolated from a contaminated estuarine sediment sample with mine tailing from the Samarco dam disaster, which occurred in 2015 in Minas Gerais State, Brazil. We report here a draft genome sequence (3.6 Mb) of this bacterial strain.
B. safensis
exhibited strong resistance to heavy metals.
Chronic intentional chicken bone ingestion mimicking inflammatory bowel disease
Authors: Dines Jacob T , Harvey Amie
Published: June 2021

Ingestion of food by-products, such as peach pits, chicken bones and fish bones, may lead to intestinal complications. The ingestion of the foreign body is often acute and non-intentional. Acute and life-threatening complications include intestinal perforation or obstruction. Sharp-pointed objects are associated with an estimated 35% rate of complications within the gastrointestinal tract prior to passage and require prompt removal. Endoscopic retrieval is often recommended if foreign objects have not transited beyond the proximal duodenum. We present a unique case of a previously healthy 23-year-old male suffering months of abdominal pain. While the initial presentation and imaging were suspicious for Crohn’s disease, the endoscopic findings were unexpected. Numerous chicken bone fragments were clustered in the caecum and in the terminal ileum. The distal terminal ileum was edematous and ulcerated. Subsequent patient history revealed years of chronic and intentional foreign body consumption with recent onset of abdominal pain.