bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Radiation on Hydromagnetic Mixed Convective Flow in a Vertical Channel Filled With Porous Media: A Thermal Nonequilibrium Approach
Authors: Renu K. M. , Kumar Ashok
Published: January 2020

This work addresses the magnetic and radiation effects on the fully developed mixed convective flow in a vertical channel occupied by a porous medium with the thermal nonequilibrium state. The assumption that the fluid is electrically conducted is taken into account and permitted by a uniform transversal magnetic field while the temperature of the wall is changing linearly with the direction of the fluid flow. The spectral collocation technique is used for the numerical solution, whereas the analytical solution is governed for the special case when the drag force F* and the ratio of porosity-scaled thermal conductivity γ are zero. It is observed that, in the buoyancy assisted case, the fluid flow for Ra<102, (Nuf) increased near the wall with increasing the Hartmann number (M). Beyond this when Ra≥102, (Nuf) is decreased with increasing M. It is also perceived that there exists an interval [0,H0] in which (Nuf) increases with increasing M as well as increasing radiation parameter Rd, furthermore beyond the value of H0, Nuf decreasing asymptotically. While for the buoyancy opposed case, the flow separation and inflection point appear in the velocity profile for different values of M, further both the flow separation and inflection point are dying out as M increases. Overall, for the both cases, the magnetic and radiation parameters are stabilizing the flow in the system.
The Rigid-Flexible-Thermal Coupled Analysis for Spacecraft Carrying Large-Aperture Paraboloid Antenna
Authors: Cui Yaqi , Lan Peng , Zhou Haitao , Yu Zuqing
Published: January 2020

Since the thermal load would adversely introduce degradation to the normal operation of spacecraft, resulting in unpredictable thermal-dynamic behavior, thermomechanical coupling problems are important and have been investigated extensively. Based on the absolute nodal coordinate formulation (ANCF), a thermal integrated ANCF thin plate element based on the unified description is constructed, which could depict the displacement and the temperature field integratedly. By means of the proposed element, the heat transfer and continuum mechanics are integrated in the unified finite element method (FEM) mesh of revolving paraboloid antenna. Additionally, the ANCF reference node is introduced for describing the rigid central hub where the antenna is mounted on to make the rigid-flexible-thermal coupled response being captured in a unified analysis procedure. The solar radiation input and the surface emitting radiation are included in the heat transfer equations. Furthermore, the influence of the rigid body motion and the deformation on the radiant absorption are also considered with the self-shadowing. The established rigid-flexible-thermal coupled simulation is performed on a modified generalized-α integrator which solves the set of multidisciplinary governing equations synchronously. For revealing the nonlinear behavior of the rigid-flexible-thermal coupled system, the observed thermally induced vibration and perturbation on the pointing accuracy of the spacecraft are given in the results, and the feasibility of the presented method is proved.
Momentum Least Mean Square Paradigm for the Measurement of Nonlinear CARAR System Parameters
Authors: Chaudhary Naveed Ishtiaq , Ahmed Mateen , Dedovic Nebojsa , Raja Muhammad Asif Zahoor
Published: January 2020

This study presents a variant of least mean square (LMS) algorithm, i.e., momentum LMS (M-LMS), with faster convergence speed for measuring the system parameter of linear as well as nonlinear control autoregressive autoregressive (CARAR) models. The M-LMS effectively exploits the input/output data by utilizing the previous gradients information in update rule to avoid trapping in local minimum (MNM) and yields better convergence behavior than conventional LMS approach. The speedy convergence of M-LMS is achieved by increasing the proportion of previous gradients but at the cost of little compromise in final steady-state behavior. The correctness of the M-LMS is established by effective optimization of the linear as well as nonlinear CARAR model identification. The robustness of the scheme is verified through accurate measurement of CARAR systems parameters for various noise levels. The statistical analyses based on multiple independent trials through proximity measures in terms of fitness, mean squared error, and Nash Sutcliffe efficiency further validated the superior performance of M-LMS for identification of CARAR models.
Impact of Size and Shape of Equine Femoral Subchondral Bone Cysts With a Transcondylar Screw on Predicted Bone Formation Area in a Finite Element Model
Authors: Frazer Lance L. , Santschi Elizabeth M. , Ring Scott J. , Hewitt Ross E. , Fischer Kenneth J.
Published: January 2020

Equine subchondral bone cysts (SBCs) develop most often in the medial femoral condyle (MFC) of yearlings intended for performance. SBCs often cause lameness and can cause secondary injuries to the meniscus and tibial cartilage. A novel surgical technique using a transcondylar lag screw (TLS) across an MFC SBC has shown success in lameness resolution and radiographic healing of MFC SBC. In a previous study using finite element analysis, our lab showed that a TLS stimulated bone formation on the inner surface of the SBC and altered third principal stress vectors to change the direction of surface compression to align with the screw axis. This work extended the previous study, which was limited by the use of only one idealized SBC. Our objective was to test SBCs of several sizes and shapes in a newly developed equine stifle FEM with a TLS to determine how cyst size affects bone formation stimulation. This study found that a transcondylar screw is most effective in stimulating bone formation in cysts of greater height (proximal-distal). The TLS increases stress stimulus in the bone around the cyst to promote bone apposition and directs compression across the cyst. If full penetration of the screw through the cyst is possible, it is recommended that the transcondylar screw be used to treat subchondral bone cysts. For the treatment of smaller cysts that are not accessible by the current screw surgical approach, future work could study the efficacy of a dual-pitch headless screw that may reach smaller cysts.
Nonanatomic Placement of Posteromedial Meniscal Root Repairs: A Finite Element Study
Authors: Steineman Brett D. , LaPrade Robert F. , Haut Donahue Tammy L.
Published: January 2020

Nonanatomic placement of posteromedial meniscal root repairs alters knee mechanics; however, little is known about how the position and magnitude of misplacement affect knee mechanics. Finite element knee models were developed to assess changes in cartilage and meniscus mechanics for anatomic and various nonanatomic repairs with respect to intact. In total, 25 different repair locations were assessed at loads of 500 N and 1000 N. The two-simple-suture method was represented within the models to simulate posteromedial meniscal root repairs. Anatomic repairs nearly restored total contact area; however, meniscal hoop stress decreased, meniscal extrusion increased, and cartilage–cartilage contact area increased. Repairs positioned further posterior altered knee mechanics the most and repairs positioned further anterior restored knee mechanics for posteromedial root repairs. Despite this, repair tension increased with further anterior placement. Anterior placement of repairs results in more restorative contact mechanics than posterior placement; however, anterior placement also increased the risk of suture cut-out or failure following repairs. Anatomic placement of repairs remains the best option because of the risks involved with anterior placement; however, suture methods need to be improved to better restore the strength of repairs to that of the native insertion. Proper placement of repairs is important to consider with meniscal root repairs because misplacement may negatively affect cartilage and meniscus mechanics in patients.
China’s improving inland surface water quality since 2003
Authors: Ma Ting , Zhao Na , Ni Yong , Yi Jiawei , Wilson John P. , He Lihuan , Du Yunyan , Pei Tao , Zhou Chenghu , Song Ci , Cheng Weiming
Published: January 2020

China’s inland water quality has been markedly improved since 2003 notwithstanding regional variability.
Stick-slip dynamics of cell adhesion triggers spontaneous symmetry breaking and directional migration of mesenchymal cells on one-dimensional lines
Authors: Hennig K. , Wang I. , Moreau P. , Valon L. , DeBeco S. , Coppey M. , Miroshnikova Y. A. , Albiges-Rizo C. , Favard C. , Voituriez R. , Balland M.
Published: January 2020

Cell motility can be initiated without prior cytoskeleton polarity by the stochastic stick-slip dynamics of cell adhesions.
An electrically pumped surface-emitting semiconductor green laser
Authors: Ra Yong-Ho , Rashid Roksana Tonny , Liu Xianhe , Sadaf Sharif Md. , Mashooq Kishwar , Mi Zetian
Published: January 2020

Ultrasmall semiconductor lasers can improve the efficiency and resolution of next-generation displays by 10 to 100 times.
The genetic mechanism of selfishness and altruism in parent-offspring coadaptation
Authors: Wu Min , Walser Jean-Claude , Sun Lei , Kölliker Mathias
Published: January 2020

Two genes coordinate selfishness and altruisim, and more than 1600 genes are associated with parenting in mothers or offspring.
N-induced lattice contraction generally boosts the hydrogen evolution catalysis of P-rich metal phosphides
Authors: Cai Jinyan , Song Yao , Zang Yipeng , Niu Shuwen , Wu Yishang , Xie Yufang , Zheng Xusheng , Liu Yun , Lin Yue , Liu Xiaojing , Wang Gongming , Qian Yitai
Published: January 2020

The HER activities of P-rich transition metal phosphides can be substantially boosted by N-induced lattice contraction.
Summer soil drying exacerbated by earlier spring greening of northern vegetation
Authors: Lian Xu , Piao Shilong , Li Laurent Z. X. , Li Yue , Huntingford Chris , Ciais Philippe , Cescatti Alessandro , Janssens Ivan A. , Peñuelas Josep , Buermann Wolfgang , Chen Anping , Li Xiangyi , Myneni Ranga B. , Wang Xuhui , Wang Yilong , Yang Yuting , Zeng Zhenzhong , Zhang Yongqiang , McVicar Tim R.
Published: January 2020

Extra water loss from earlier spring greening dries soils locally in summer, but can moisten soils in areas downwind.
Citrus polymethoxyflavones attenuate metabolic syndrome by regulating gut microbiome and amino acid metabolism
Authors: Zeng Su-Ling , Li Shang-Zhen , Xiao Ping-Ting , Cai Yuan-Yuan , Chu Chu , Chen Bai-Zhong , Li Ping , Li Jing , Liu E-Hu
Published: January 2020

Citrus polymethoxyflavones prevent metabolic syndrome by modulating gut dysbiosis and altering branched-chain amino acids.
Present-day volcanism on Venus as evidenced from weathering rates of olivine
Authors: Filiberto Justin , Trang David , Treiman Allan H. , Gilmore Martha S.
Published: January 2020

Our results imply that lava flows with high emissivity on Venus are less than several years old, and Venus is volcanically active.
Inverse design of porous materials using artificial neural networks
Authors: Kim Baekjun , Lee Sangwon , Kim Jihan
Published: January 2020

We have developed a user-desired generative adversarial network and used them to generate 121 zeolite materials.
Bio-coal: A renewable and massively producible fuel from lignocellulosic biomass
Authors: Cheng Bin-Hai , Huang Bao-Cheng , Zhang Rui , Chen Ya-Li , Jiang Shun-Feng , Lu Yan , Zhang Xue-Song , Jiang Hong , Yu Han-Qing
Published: January 2020

A new type of energy is produced via a fast pyrolysis coupled with atmospheric distillation from lignocellulosic biomass wastes.
Heparin-mediated delivery of bone morphogenetic protein-2 improves spatial localization of bone regeneration
Authors: Hettiaratchi Marian H. , Krishnan Laxminarayanan , Rouse Tel , Chou Catherine , McDevitt Todd C. , Guldberg Robert E.
Published: January 2020

Heparin-based microparticles improve spatial localization of BMP-2 delivery, decreasing bone formation outside of the injury site.
Expansion-tolerant architectures for stable cycling of ultrahigh-loading sulfur cathodes in lithium-sulfur batteries
Authors: Shaibani Mahdokht , Mirshekarloo Meysam Sharifzadeh , Singh Ruhani , Easton Christopher D. , Cooray M. C. Dilusha , Eshraghi Nicolas , Abendroth Thomas , Dörfler Susanne , Althues Holger , Kaskel Stefan , Hollenkamp Anthony F. , Hill Matthew R. , Majumder Mainak
Published: January 2020

We report expansion-tolerant architectures in ultrahigh-loading sulfur cathodes inspired by particle agglomeration theories.
Unraveling the atomic structure, ripening behavior, and electronic structure of supported Au
20
clusters
Authors: Li Zhe , Chen Hsin-Yi Tiffany , Schouteden Koen , Picot Thomas , Liao Ting-Wei , Seliverstov Aleksandr , Van Haesendonck Chris , Pacchioni Gianfranco , Janssens Ewald , Lievens Peter
Published: January 2020

Pyramidal Au
20
clusters are intactly deposited and visualized at the single cluster level.
Regulation of host-microbe interactions at oral mucosal barriers by type 17 immunity
Authors: Gaffen Sarah L. , Moutsopoulos Niki M.
Published: January 2020

Preserving a homeostatic balance with resident microbial communities of the oropharynx depends on a measured dose of type 17 immunity.
Human T cell response to CD1a and contact dermatitis allergens in botanical extracts and commercial skin care products
Authors: Nicolai Sarah , Wegrecki Marcin , Cheng Tan-Yun , Bourgeois Elvire A. , Cotton Rachel N. , Mayfield Jacob A. , Monnot Gwennaëlle C. , Le Nours Jérôme , Van Rhijn Ildiko , Rossjohn Jamie , Moody D. Branch , de Jong Annemieke
Published: January 2020

CD1a, an abundant lipid antigen–presenting molecule in human skin, mediates T cell responses to small contact allergens.
Targeted deletion of PD-1 in myeloid cells induces antitumor immunity
Authors: Strauss Laura , Mahmoud Mohamed A. A. , Weaver Jessica D. , Tijaro-Ovalle Natalia M. , Christofides Anthos , Wang Qi , Pal Rinku , Yuan Min , Asara John , Patsoukis Nikolaos , Boussiotis Vassiliki A.
Published: January 2020

PD-1 ablation regulates metabolism-driven lineage fate commitment of myeloid progenitors and differentiation of effector myeloid cells (see the related Focus by
Rudd
).
A new perspective in cancer immunotherapy: PD-1 on myeloid cells takes center stage in orchestrating immune checkpoint blockade
Authors: Rudd Christopher E.
Published: January 2020

PD-1 mediates antitumor immunity by regulating lineage fate commitment and function of myeloid cells (see the related Research Article by

Strauss
et al.

).
Cis
interactions make immune checkpoint blockade more
trans
-parent
Authors: Khatwani Natasha , Pillai Asha B.
Published: January 2020

PD-L1:CD80 cis-heterodimer formation preferentially blocks CTLA-4 trans-signaling while allowing CD28-mediated effector T cell activation.
“B”-fing up immune-mediated diseases
Authors: Hsu Jeffrey , Griffin Gabriel K.
Published: January 2020

Extensive characterization of B cell receptor repertoires across six immune-mediated diseases reveals novel insights into disease pathogenesis.
Genetics of Host-Controlled Restriction and Modification of Deoxyribonucleic Acid in
Escherichia coli
Authors: Lederberg Seymour
Published: January 2020

Lederberg, Seymour
(Brown University, Providence, R.I.). Genetics of host-controlled restriction and modification of deoxyribonucleic acid in
Escherichia coli
. J. Bacteriol.
91:
1029–1036. 1966.—The locus for the host specific restriction and modification of deoxyribonucleic acid in
Escherichia coli
has been mapped by matings between mutants for these characters in strains K-12, C600, and B. Linkage analysis and kinetics of marker transfer indicate that a single or closely linked multiple chromosomal site located about 4 min counterclockwise to leucine is responsible for these activities. Secondary factors which affect the quantitative level of restriction also were detected. Wild-type recombinants were isolated in crosses between
rm
−
(restriction or modification, or both) mutants. The expression in zygotes of the restrictionless character of a
rm
−
donor is masked by a separate, physiological impairment of restriction, which results from mating and is independent of the modification state of the donor. The relevance of the restriction character to mating incompatibilities in these and other bacterial strains is considered.
Transformation During Mixed Pneumococcal Infection of Mice
Authors: Conant James E. , Sawyer William D.
Published: January 2020

The recent demonstration by others of transformation during peritoneal infection of mice by two genetically distinct pneumococcal strains supports the notion that transformation may be significant in pneumococcal infection in nature. These studies confirm the occurrence of transformation during mixed infection of mice and define some conditions for its occurrence and its significance. Mice were inoculated with deoxyribonucleic acid (DNA) donor (small type III capsule, low virulence, streptomycin-susceptible) and recipient (noncapsulated, low virulence, streptomycin-resistant) pneumococci, and the bacteremia in mice that died was evaluated. Transformants (large type III capsule, virulent, streptomycin-resistant) were isolated from up to 80% of mice that died from mixed peritoneal infection. Transformation occurred in mice that received donor and recipient 6 hr apart; hence, active DNA was released and competence developed during growth in vivo. Transformation was detected only with progressive infection by both strains, and then transformants were few in the blood and apparently were not responsible for the death of the animals. In doubly infected mice treated with streptomycin, transformation was enhanced; transformants numerically dominated the bacteremia and seemed to cause the death of the mice. Transformation was also demonstrated for the first time during infection of the respiratory tract.
Effect of Thiol-binding Reagents on the Metabolism of
Chromatium
D
Authors: Hurlbert R. E.
Published: January 2020

Thiosulfate, intracellular sulfur, and acetate utilization by
Chromatium
D were inhibited by iodoacetamide,
N
-ethylmaleimide (NEM),
p
-hydroxymercuribenzoate (CMB), and HgCl
2
. Pyruvate, sulfide, and sulfite utilization were insensitive to iodoacetamide, and were less sensitive to NEM, CMB, and HgCl
2
than thiosulfate, intracellular sulfur, and acetate utilization. The effect of the thiol-binding reagents on cell viability was dependent upon the method of exposure; cells exposed to the thiol-binding reagents in the presence of thiosulfate were protected from the killing action of these agents, but not from their inhibitory effect. Although the inhibitory effects of the thiol-binding reagents could, in some cases, be attributed to their effect on viability, they were inhibitory under conditions where viability was unaffected. The most straightforward results were obtained with iodoacetamide, which revealed a sharp separation in sensitivities between the systems tested but had no effect on cell viability. The results are consistent with the hypothesis that thiols are involved in thiosulfate, intracellular sulfur, and acetate utilization.
Surface Structure of
Bacillus stearothermophilus
Ribosomes
Authors: Bassel Alix , Campbell L. Leon
Published: January 2020

No significant differences were noted in either the size or in the arrangement of the surface filaments of the ribosomes of
Bacillus stearothermophilus
and
Escherichia coli
.
Thermal Reversal of Ultraviolet-Irradiation Damage in
Salmonella typhimurium
Authors: Gough Michael
Published: January 2020

Effects of ultraviolet irradiation on lysogenic and nonlysogenic
Salmonella typhimurium
grown at 25 C are partially reversed by shifting cultures to 43 C immediately after irradiation.
Evaluation of Histoplasmin for the Presence of H and M Antigens: Some Difficulties Encountered in the Production and Evaluation of a Product Suitable for the Immunodiffusion Test
Authors: Gross Herman , Bradley Georgia , Pine Leo , Gray Sam , Green James H. , Harrell W. Knox
Published: January 2020

The development of a single histoplasmin suitable for use in immunodiffusion testing of a variety of human histoplasmosis sera depends not only upon the presence of both antigens, but on relative concentration of one to the other, and perhaps on the chemical characteristics of the H and M antigens of a given strain.
Use of urease test disks in the identification of mycobacteria
Authors: Murphy D B , Hawkins J E
Published: January 2020

Use of commercially available urea differentiation disks is a rapid and convenient means of determining the urease activity of mycobacteria. In the study performed, paper disks containing Ewing's Urea R Broth were compared with two other methods of testing for urease production. Over 1,500 tests were performed with recent patient isolates from which at least 15 different species of mycobacteria were identified. The tests were read at intervals for 72 h, and a comparison of test results as to rapidity and accuracy for each species was tabulated. The urea disks showed a faster reaction time when compared with the other two methods. They also showed a high percentage (79 to 100%) of reliability for each species on the first run, based on the expected response.
Rabies virus inactivation by binary ethylenimine: new method for inactivated vaccine production
Authors: Larghi O P , Nebel A E
Published: January 2020

The inactivation dynamics of rabies virus (PV strain) by binary ethylenimine, and the immunogenic properites and the stability of the vaccines prepared using this agent, were studied. Binary ethylenimine at a final concentration of 0.01 M was prepared wtih 2-bromoethylamine hydrobromide in alkaline solutions, either separately from or in suspensions of rabies virus propagated in BHK cells. The infectivity of virus suspensions containing more than 108 plaque-forming units per 0.1 ml was inactivated in 2 h when the inactivating agent was prepared before its addition to the suspensions, and in3 h when prepared directly in the suspensions. Liquid vaccines prepared in this manner and stored at different temperatures maintained potency for 1 month at 37 degrees C and for 6 months at 4 degrees C and 22 to 25 degrees C. Lyophilized vaccine maintained its potency for 6 months at the three temperatures. The inactivated vaccine mixed with aluminum or oil adjuvant at high dilutions protected guinea pigs against challenge. This safer procedure for rabies virus inactivation offers promise for the production of effective vaccines for the immunization of dogs and cattle.
Development and characterization of high-titered, group-specific fluorescent-antibody reagents for direct identification of rickettsiae in clinical specimens
Authors: Hébert G A , Tzianabos T , Gamble W C , Chappell W A
Published: January 2020

Rabbits were inoculated with purified antigen preparations of Coxiella burnetii and representative species of the spotted fever and typhus groups of rickettsiae. Their antibody responses were monitored by complement fixation tests; high-titered antisera were fractionated with ammonium sulfate and then labeled with fluorescein isothiocyanate by the dialysis method. The conjugates had homologous 3+ staining titers of 1:256 to 1:2,048 and did not exhibit nonspecific staining. The Rickettsia rickettsii, R. conorii, and R. akari conjugates reacted only with rickettsiae of the spotted fever group; the R. canada, R. prowazekii, and R. typhi conjugates were specific for the typhus group rickettsiae; and the C. burnetii conjugate stained only homologous organisms. One of these conjugates (R. rickettsii) is currently being used to identify rickettsiae in clinical specimens and has already proven its value as a diagnostic tool.
Combining cervical and anal-canal specimens for gonorrhea on a single culture plate
Authors: Judson F N , Werness B A
Published: January 2020

To reduce the cost of detecting gonorrhea, we studied the effect on diagnostic sensitivity of combining two culture specimens on the same plate of modified Thayer-Martin medium, using specimens from 7,787 women seen consecutively in the clinic. There was no significant difference (P greater than 0.05) between one cervical and one anal-canal specimen placed on separate plates (C,A) and these two specimens combined but spaced apart on a single plate (C/A), or between two cervical specimens combined but spaced apart on the same plate (C/C) and C/A. Therefore, C/C, C/A, and C,A have equivalent diagnostic sensitivities. C/A detected 5.68% more women with gonorrhea than did a single cervical culture (C) (P less than 0.001). If C/A were to replace C,A for culture specimens from women seen in venereal disease clinics and C for specimens taken and cultured outside of venereal disease, gonorrhea control programs in the United States could realize savings in excess of $2.5 million per year.
Identification of Pseudomonas aeruginosa by pyocyanin production on Tech agar
Authors: Reyes E A , Bale M J , Cannon W H , Matsen J M
Published: January 2020

Pseudomonas aeruginosa is the only gram-negative bacillus capable of producing the very distinctive water-soluble pigment pyocyanin. We evaluated the reliability of this characteristic as a unique test for the identification of this organism by using Tech agar (BBL Microbiology Systems, Cockeysville, Md.) medium. A retrospective and prospective analysis was performed with a total of 835 strains of P. aeruginosa; 818 (98%) produced pigment within 48 h of incubation, and 96% of those which produced pigment were positive after overnight incubation. Seventeen strains (2.0%) failed to produce pigment; 15 were mucoid strains from patients with cystic fibrosis. Tech agar is an effective, simple, and inexpensive medium for P. aeruginosa identification and may be used as a unique test for all potential P. aeruginosa isolates (beta hemolytic on blood agar; lactose-negative, oxidase-positive colonies). Nonpigmented mucoid strains, as well as other nonpigmented organisms, will require additional testing to ensure proper identification.
Enhancement of coagglutination reactions of the Phadebact gonococcus test by ethylenediaminetetraacetate and ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetate
Authors: Izakson I , Morse S A
Published: January 2020

Incubation of gonococci under conditions optimal for autolysis resulted in increased sensitivity and enhancement of the coagglutination reaction of the Phadebact gonococcus test. These conditions included an alkaline pH (pH 8.3) and the presence of divalent cation chelators such as ethylenediaminetetraacetic acid or ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid. Heating cell suspensions at 90 degrees C for 15 min before assay by coagglutination produced a further increase in sensitivity and enhancement of the reaction. Gonococcal lipopolysaccharide was found to be an important antigen in these coagglutination reactions. The detection of lipopolysaccharide was markedly enhanced by the addition of chelating agents.
Assay of human rotavirus antibody by immune adherence hemagglutination with a cultivable human rotavirus as antigen
Authors: Matsuno S , Inouye S , Hasegawa A , Kono R
Published: January 2020

A cultivable human rotavirus, Wa, was propagated in MA-104 cells and used as an antigen in immune adherence hemagglutination (IAHA) and complement fixation (CF) tests. IAHA antibody titers of sera from normal humans were found to be eightfold higher than CF antibody titers. The IAHA antibody determination with the Wa antigen is considered to be especially useful for the seroepidemiological studies of human rotavirus infections.
Infection caused by Yersinia enterocolitica serotype O:21
Authors: Karmali M A , Toma S , Schiemann D A , Ein S H
Published: January 2020

Yersinia enterocolitica serotype O:21, biotype 3 (Wauters) was isolated from the appendix and stool of a 7-year-old girl. The same organism was later isolated in pure culture from pus from a postoperative wound infection in this patient. She developed a significant serological response (titer of 800). There was thus strong clinical evidence of pathogenicity associated with this rather uncommon human serotype. Laboratory studies in vitro and in vivo pathogenicity showed that the organism was autoagglutinable, Serény test positive, and HeLa cell invasive; when given orally to mice, it produced diarrhea and subsequently death. The results of laboratory studies of virulence correlated closely with the clinical evidence of pathogenicity in this case.
Factors affecting griseofulvin susceptibility testing of Trichophyton rubrum in microcultures
Authors: Granade T C , Artis W M
Published: January 2020

A microculture broth assay system for griseofulvin susceptibility testing of Trichophyton rubrum was further characterized. The effects of mass and number of colony-forming units of a fragmented mycelial inoculum, 5- or 8-day incubation periods, 25 or 32 degrees C incubation temperatures, and the solvents used to dissolve griseofulvin on the minimal inhibitory concentration (MIC) of griseofulvin were determined. An inoculum density with an absorbance of 0.600 at 450 nm ensured successful inoculation of all microcultures. Reduction of the inoculum mass to an absorbance of 0.200 lowered the number of colony-forming units in the inoculum by 60 to 80%. This decreased the efficiency of inoculation but did not alter the resulting MIC. There was no correlation between MIC and the number of colony-forming units used to initiate growth. Neither incubation temperature nor the length of incubation affected the MIC. The use of either acetone or ethanol to solubilize griseofulvin likewise had no effect on the MIC. The mean reproducibility of the MICs determined with the microculture method was 96%.
Acetamide broth for isolation of Pseudomonas aeruginosa from patients with cystic fibrosis
Authors: Kelly N M , Falkiner F R , Keane C T
Published: January 2020

The recovery of Pseudomonas aeruginosa was enhanced by incubating specimens in acetamide broth before subculture on cetrimide agar. This finding is of particular value in screening pediatric patients with cystic fibrosis for carriage of P. aeruginosa.
Evaluation of three simple and rapid immunological tests for detection of heat-labile enterotoxin of enterotoxigenic Escherichia coli
Authors: Sen D , Saha M R , Pal S C
Published: January 2020

Three simple immunological tests, the modified Elek (Biken) test, the modified staphylococcal coagglutination test, and the rapid GM1-horseradish peroxidase-enzyme-linked immunosorbent assay have been evaluated for detection of heat-labile enterotoxin of enterotoxigenic Escherichia coli. Of the 100 coded E. coli strains tested, 94 gave consistent results with all the three immunological tests; a discrepancy was observed in only 6 strains. Identical results were obtained when the Biken test was conducted with complete and incomplete Biken kits (Meguro Institute Ltd., Osaka, Japan). All three immunological tests evaluated in this study were found to be sensitive and simple and can be easily adopted by any laboratory for detection of heat-labile enterotoxins of enterotoxigenic E. coli strains.
Use of the API NeIdent system for identification of pathogenic Neisseria spp. and Branhamella catarrhalis
Authors: Janda W M , Morello J A , Bohnhoff M
Published: January 2020

The API NeIdent system (Analytab Products, Plainview, N.Y.) was evaluated for identifying Neisseria spp. and Branhamella catarrhalis commonly isolated from clinical specimens. The system identified 90% of 303 Neisseria gonorrhoeae isolates, 71% of 113 Neisseria meningitidis isolates, and 63% of 16 Neisseria lactamica isolates but failed to identify any of 22 B. catarrhalis isolates. Testing of gonococcal strains of various auxotypes revealed no relationship between nutritional requirements and NeIdent profile numbers. With the Neisseria species, interpretation of the cinnamaldehyde-coupled beta-naphthylamine reactions was difficult and resulted in profile numbers not listed in the Profile Register. Positive resazurin-glucose reactions resulted in unlisted numbers for all B. catarrhalis strains. Inconsistent results were also obtained when 62 N. gonorrhoeae isolates were tested more than once on the strip. In all cases, profile variability and failure to identify these organisms were related to the beta-naphthylamide substrate tests. Expansion of the data base and modification of the substrate formulations or their interpretive criteria may increase the reliability of the NeIdent system for identifying Neisseria spp. and B. catarrhalis.
Ten-minute detection of group A streptococci in pediatric throat swabs
Authors: Chang M J , Mohla C
Published: January 2020

A 10-min latex agglutination test kit, Culturette Brand Ten-Minute Group A Strep ID (Marion Scientific, Div. of Marion Laboratories, Inc., Kansas City, Mo.), was assessed for the rapid detection of group A beta-hemolytic streptococcus directly from a throat swab. Four hundred and thirty-five throat swab specimens from children with suspected group A streptococcal infection were tested by the Ten-Minute Group A Strep ID and by concurrent conventional culture. The strep test was effective in detecting group A streptococcal infection; 90% (63/70) of culture-positive specimens gave positive latex tests. The specificity of the test was 99.2% (362/365). The predictive values were 95.5% for positives and 98.1% for negatives. Overall agreement with culture was 98% (425/435). This test offers a sensitive and specific method for the early detection of group A beta-hemolytic streptococci in throat swabs of children and would be most useful in a hospital laboratory or pediatrician's office.
Simplified bioassay method for measurement of flucytosine or ketoconazole
Authors: Bodet C A , Jorgensen J H , Drutz D J
Published: January 2020

A simple agar-well diffusion bioassay suitable for measurement of flucytosine or ketoconazole was developed by using Candida pseudotropicalis ATCC 46764 as the assay organism. A test medium composed of (per liter) 7 g of Trypticase peptone, 7 g of YNB (yeast-nitrogen base), 15 g of glucose, and 15 g of agar was seeded with an inoculum which had been grown to no. 2 McFarland turbidity after 4 to 6 h in YNB-glucose broth. Determinations of flucytosine or ketoconazole were performed without necessity of heating or diluting of serum samples to alleviate amphotericin B interference. A linear relationship between zone diameters and log10 concentration of the drugs was observed over the pharmacologically relevant ranges of 25 to 160 micrograms/ml for flucytosine and 0.5 to 20 micrograms/ml for ketoconazole. The mean coefficient of variability for samples measured on 5 separate days was 2.4% for flucytosin and 4.0% for ketoconazole. This assay represents a significant improvement over previous bioassay methods in that a single test system may be used for measurement of either flucytosine or ketoconazole, no serum dilution or pretreatment is required, inoculum preparation is accomplished entirely on the day of the assay, and sharp, clearly defined zones of inhibition are obtained with both drugs.
Chemically defined medium for oral microorganisms
Authors: Socransky S S , Dzink J L , Smith C M
Published: January 2020

We formulated a chemically defined medium consisting of 14 inorganic salts, 23 amino acids, 23 vitamins and other factors, seven purines and pyrimidines, and glucose which would successfully support the growth of a wide variety of oral microorganisms. Of 204 oral isolates representing 20 genera and 60 species, 197 maintained viability through six serial transfers.
Comparison of the detection of herpes simplex virus in direct clinical specimens with herpes simplex virus-specific DNA probes and monoclonal antibodies
Authors: Fung J C , Shanley J , Tilton R C
Published: January 2020

A comparison of two commercially available kits for rapid herpes simplex virus (HSV) detection directly in patient specimens was performed. The immunofluorescence assay (IFA) utilized monoclonal antibodies to HSV, and the DNA probe assay utilized three HSV sequences cloned into pBR322. A sample of 243 specimens received in viral transport medium were inoculated into MRC-5 tissue cultures. The remainder of the specimen was centrifuged, and the cellular pellet was examined by IFA and DNA probes. One hundred and sixty-two (66.7%) specimens were considered satisfactory for IFA and DNA probe testing, based on a criterion of observing greater than or equal to 2 intact cells per high-power field. Of the 162 specimens, 35 (21.6%) yielded HSV by culture. By IFA, the sensitivity of detecting HSV culture-positive specimens was 77.1%; specificity was 100%, positive predictive value was 100%, and negative predictive value was 93.3%. DNA probe sensitivity was 71.4%; specificity was 90.6%; positive predictive value was 67.6%; and negative predictive value was 92%. Forty-four (27.2%) of the 162 specimens exhibited nonspecific cytoplasmic staining with the DNA probe. IFA and DNA probe assays can be completed in 2 to 3 h, whereas the average time to culture positivity in this series was 2.2 days. Rapid HSV diagnosis can aid in timely and appropriate patient management.
Enzyme-linked immunosorbent assay for detection of serum antibodies to Pasteurella haemolytica cytotoxin (leukotoxin) in cattle
Authors: Mosier D A , Confer A W , Hall S M , Gentry M J , Panciera R J
Published: January 2020

An enzyme-linked immunosorbent assay (ELISA) was developed for detection of bovine serum antibodies to the cytotoxin (leukotoxin) of Pasteurella haemolytica. A partially purified, cytotoxic, and immunogenic protein obtained from supernatants of logarithmic-phase P. haemolytica was used as the ELISA antigen. Preadsorption of sera with various cytotoxic, somatic, and capsular antigen preparations demonstrated that the assay was specific for anticytotoxin antibodies. ELISA anticytotoxin titers had a strong, significant correlation to cytotoxin-neutralizing-antibody titers. The ELISA, however, was more rapid and allowed for greater numbers of samples to be run than did the neutralization technique. ELISA anticytotoxin titers were high in cattle vaccinated with a live P. haemolytica vaccine, whereas unvaccinated cattle and cattle receiving a P. haemolytica bacterin had low ELISA anticytotoxin titers. A significant positive correlation between ELISA titers and resistance to experimental bovine pneumonic pasteurellosis was present.
Clinical evaluation of three urine screening tests
Authors: Murray P R , Smith T B , McKinney T C
Published: January 2020

Evaluations of screening tests for bacteriuria have traditionally compared the test results with those of quantitative urine cultures. However, many patients with symptomatic urinary tract infections can have less than 10(5) CFU/ml in their urine. Therefore, the results of urine culture and three screening tests (Bac-T-Screen, Chemstrip LN [which tests for leukocyte esterase and nitrate reductase], and Gram stain) were correlated with the clinical classification of urinary tract infection. The Bac-T-Screen test detected 98, 93, and 100% of the infections classified as probable, possible, and asymptomatic, respectively. In contrast, the Gram stain, leukocyte esterase, and nitrate reductase tests were all insensitive screening tests for infection. Additionally, only 45% of the patients with probable infections had greater than or equal to 10(5) CFU/ml. Thus, the majority of infected patients would not have been detected if quantitative urine cultures were used alone.
Enzyme-linked immunosorbent assay for diagnosis of chronic Q fever
Authors: Péter O , Dupuis G , Bee D , Lüthy R , Nicolet J , Burgdorfer W
Published: January 2020

From 1982 through 1987 we diagnosed 13 chronic Q fever cases. Clinically these patients presented a culture-negative endocarditis, and all but two had high complement-fixing antibody titers to Coxiella burnetii phase I (reciprocal titer above 200). With the enzyme-linked immunosorbent assay (ELISA), titers of immunoglobulin G (IgG) to phases I and II of C. burnetii averaged 158,000 and 69,900, respectively, whereas they reached 300 and 3,200 in acute Q fever cases. Similarly, IgA to both phases of C. burnetii and IgM to phase I were consistently higher during chronic than acute Q fever. The serological follow-up of one patient with chronic Q fever over a 4-year period showed a good correlation between the titers of IgG and IgM antibody titers detected by ELISA and indirect fluorescent-antibody test (IFA) to both phases of C. burnetii. Few discrepancies appeared with IgA. Shortly after initiation of antibiotic treatment, a slow and steady decrease of the antibody titers to C. burnetii phases I and II was observed. The complement fixation, IFA, and ELISA tests showed the same type of antibody response. The ELISA proved to be an excellent diagnostic test for chronic Q fever. It distinguished negative from positive reactions clearly, and results were highly reproducible. The reading is objective, and the test is simple to perform and more sensitive than the IFA and complement fixation tests. The ELISA is recommended for serologic evaluation of patients with chronic Q fever.
Kluyvera species soft tissue infection: case report and review
Authors: Luttrell R E , Rannick G A , Soto-Hernandez J L , Verghese A
Published: January 2020

A soft tissue infection caused by Kluyvera species in a previously healthy woman is described. Successful treatment required incision and drainage of the wound in addition to administration of antibiotics. Kluyvera species are indole positive, Voges-Proskauer negative members of the family Enterobacteriaceae. Previous reports of infection due to Kluyvera species suggest that the organism is never more than an opportunistic pathogen; however, we report the first case of infection in a previously healthy host.
Amplification techniques for detection of herpes simplex virus in neonatal and maternal genital specimens obtained at delivery
Authors: Warford A L , Chung J W , Drill A E , Steinberg E
Published: January 2020

Viral culture amplification methods, including centrifugation, use of a cell pretreatment medium containing dimethyl sulfoxide and dexamethasone (DEX medium), and three commercial enzyme immunoassays (EIAs), were evaluated for use with low-titer, asymptomatic neonatal and obstetric samples obtained at delivery. The 4.5-h Ortho EIA was 59.7% sensitive at 16 h compared with 86.4% at 36 h in a spin-amplified format (SAT-EIA). After 36 h with DEX medium, the SAT-EIA was 97.3% sensitive using the 2.5-h modified Ortho EIA and 69.9% sensitive using the Fairleigh Dickinson EIA. Herpes simplex virus (HSV) cytopathic effect was reported in tube culture 1 to 2 days earlier in 8.1 to 35.9% of cells with DEX medium. Overall, the SAT-EIA using the modified Ortho EIA and cells with DEX medium detected 147 of 153 (96.1%) HSV isolates from samples obtained predelivery and 93.1% of 29 HSV positives from samples obtained at labor and delivery, with specificities of 100 and 99.9%, respectively, at 36 h.
Rapid and simple method for purification of nucleic acids
Authors: Boom R , Sol C J , Salimans M M , Jansen C L , Wertheim-van Dillen P M , van der Noordaa J
Published: January 2020

We have developed a simple, rapid, and reliable protocol for the small-scale purification of DNA and RNA from, e.g., human serum and urine. The method is based on the lysing and nuclease-inactivating properties of the chaotropic agent guanidinium thiocyanate together with the nucleic acid-binding properties of silica particles or diatoms in the presence of this agent. By using size-fractionated silica particles, nucleic acids (covalently closed circular, relaxed circular, and linear double-stranded DNA; single-stranded DNA; and rRNA) could be purified from 12 different specimens in less than 1 h and were recovered in the initial reaction vessel. Purified DNA (although significantly sheared) was a good substrate for restriction endonucleases and DNA ligase and was recovered with high yields (usually over 50%) from the picogram to the microgram level. Copurified rRNA was recovered almost undegraded. Substituting size-fractionated silica particles for diatoms (the fossilized cell walls of unicellular algae) allowed for the purification of microgram amounts of genomic DNA, plasmid DNA, and rRNA from cell-rich sources, as exemplified for pathogenic gram-negative bacteria. In this paper, we show representative experiments illustrating some characteristics of the procedure which may have wide application in clinical microbiology.
Use of terpene-based products, with and without anhydrous alcohol, as clearing agents in trichrome staining technique for intestinal protozoa
Authors: Gubash S M , Milburn L
Published: January 2020

BDH xylene substitute, a terpene-based product, and its mixture with anhydrous alcohol were found to be excellent replacements for xylene and carbol-xylene, respectively, in the trichrome staining technique applied to sodium acetate-acetic acid-Formalin-fixed fecal smears for detection of intestinal protozoa.
Amplification of bacterial 16S ribosomal DNA with polymerase chain reaction
Authors: Wilson K H , Blitchington R B , Greene R C
Published: January 2020

The sequence of small-subunit rRNA varies in an orderly manner across phylogenetic lines and contains segments that are conserved at the species, genus, or kingdom level. By directing oligonucleotide primers at sequences conserved throughout the eubacterial kingdom, we amplified bacterial 16S ribosomal DNA sequences with the polymerase chain reaction. Priming sites were located at the extreme 5' end, the extreme 3' end, and the center of 16S ribosomal DNA. The isolates tested with these primers included members of the genera Staphylococcus, Coxiella, Rickettsia, Clostridium, Neisseria, Mycobacterium, Bilophila, Eubacterium, Fusobacterium, and Lactobacillus and the family Enterobacteriaceae. Initially, the yields from the reactions were erratic because the primers were self-complementary at the 3' ends. Revised primers that were not self-complementary gave more reproducible results. With the latter primers, 0.4 pg of Escherichia coli DNA consistently gave a visible band after amplification. This method should be useful for increasing the amounts of bacterial 16S ribosomal DNA sequences for the purposes of sequencing and probing. It should have a broad range of applications, including the detection and identification of known pathogens that are difficult to culture. This approach may make it possible to identify new, nonculturable bacterial pathogens.
Molecular cloning of Ehrlichia risticii and development of a gene probe for the diagnosis of Potomac horse fever
Authors: Thaker S R , Dutta S K , Adhya S L , Mattingly-Napier B L
Published: January 2020

A gene bank of Ehrlichia risticii was constructed in plasmid vector pUC13. Five clones representing discrete regions of the E. risticii genome were tested for their ability to hybridize specifically to E. risticii DNA. None of the clones cross-hybridized with Ehrlichia equi DNA, whereas four of these clones cross-hybridized with Ehrlichia canis and Ehrlichia sennetsu DNAs. However, one clone carrying a 1-kilobase HindIII fragment of E. risticii DNA failed to cross-react with the genomes of E. sennetsu, E. canis, and E. equi in dot blot hybridization assays. The sensitivity of this probe for the detection of E. risticii DNA was approximately 0.5 pg. By using this probe, the E. risticii DNA was detected in the peripheral blood mononuclear cells of 30 experimentally infected horses by 7 days postinfection (p.i.); the detection of E. risticii DNA peaked between 14 and 17 days p.i., a period immediately after the peak of the second rise in body temperature, during leukopenia and at the onset of diarrhea. E. risticii DNA was not detectable by 25 to 30 days p.i. E. risticii DNA was not detected in noninfected control horses.