bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Investigation on the Influences of Boundary Layer Ingestion on Tip Leakage Flow Structures and Losses in a Transonic Axial-Flow Fan
Authors: Yang Zhe , Lu Hanan , Pan Tianyu , Li Qiushi
Published: June 2021

In a boundary layer ingesting (BLI) propulsion system, the fan is continuously exposed to inflow distortions. The distorted inflows lead to nonuniform loss distributions along the radial and circumferential directions. Since the rotor tip suffers from higher intensive distortion, the local loss increment is a major contributor to the BLI fan performance penalty. To explore the effects of distorted inflows on tip leakage flow evolutions and associated mechanisms for increased loss in a BLI fan, three-dimensional full-annulus unsteady simulations are conducted. Results show that about 54% of total additional losses due to distortion are formed in the tip region and more than 80% of tip region entropy generation is related to the tip leakage flow. The intensities of leakage vortex–shock interactions vary at different annulus locations. When the rotor moves into the distorted region, the vortex–shock interaction is weaker than the undistorted locations due to attenuated leakage flow. At the locations where the rotor is moving out from the distorted region, the vortex–shock interaction is notably enhanced because the front part of the blade tip airfoil suffers a higher load, resulting in a rapid vortex core expansion and eventually vortex breakdown. The increase of flow blockage in the front section of blade tip passages at local circumferential positions leads to a corresponding rise of flow loss. The findings in this study highlight the impacts of tip leakage flow on aerodynamic loss of fan working under BLI inflow distortion and provide improved understandings of loss mechanisms in a BLI fan.
Effects of Blade Pressure Side Modification on Unsteady Pressure Pulsation and Flow Structures in a Centrifugal Pump
Authors: Wu Chengshuo , Zhang Wenqi , Wu Peng , Yi Jiale , Ye Haojie , Huang Bin , Wu Dazhuan
Published: June 2021

In this paper, the effects of modifying the blade pressure side (PS) on unsteady pressure pulsation and flow structures in a low specific speed centrifugal pump are carried out by experimental and computational fluid dynamics (CFD). Seven monitor points are arranged in the circumferential direction of the impeller outlet to capture the pressure signals in the volute at flow rate of 0.2–1.6Qd. Results show that the blade PS modification introduced here can significantly alleviate the amplitude of pressure pulsation at blade passing frequency (fBPF) in all concerned operation conditions. To study the effects of blade modification on the internal flow field, the volute domain is replaced by an even outlet region for CFD analysis. The shear stress transfer (SST) turbulence model is adopted for steady-state numerical simulation while the delayed detached eddy simulation (DDES) based on the SST approach is adopted for transient simulation. Results show that local unsteady velocity fluctuation is the dominant reason for pressure pulsation in the volute. After blade PS modification, the relative velocity distribution at the impeller outlet is more uniform and the intensity of shedding vortex at the blade trailing edge (TE) decreases significantly. The change of internal flow structure improves the uniformity of circumferential velocity distribution the downstream of the impeller outlet, which leads to the decrease of pressure fluctuation amplitude in the volute. Meanwhile, the local Euler head (LEH) distribution at the impeller outlet and the blade loading of PS are presented and compared. It can be concluded that the reduction of pressure pulsation attributes to a more uniform energy distribution at the impeller outlet which is achieved by actively unloading the PS of the modified blades.
Cutting to the Point: Directly Machined Metal Molds for Directional Gecko-Inspired Adhesives
Authors: Hajj-Ahmad Amar , Suresh Srinivasan A. , Cutkosky Mark
Published: June 2021

Fabrication techniques for gecko-inspired adhesives generally target mold durability, adhesive performance, and process efficiency and simplicity. With these goals in mind, we present a micromachining process for creating reusable aluminum molds used to fabricate directional dry adhesives. The molds require deep, narrow and overhanging grooves to create sharp and angled adhesive features. This geometry precludes most traditional machining and lithographic material removal processes. The presented process is a hybrid of indenting and orthogonal machining, using a diamond-coated microtome blade as the tool. An finite element analysis reveals the local extent of work hardening as each groove is created, and helps to define a trajectory that reduces the effects of tool deflection and chip build up. The results of a series of experiments agree with predictions from the analysis and reveal a range of blade approach angles and a lower bound on groove spacing to achieve the desired geometry. This range is narrower than for molds machined from wax in previous work. Nonetheless, adhesive samples cast from the new metal molds achieve comparable performance to those previously cast from wax.
Uncertainty Reduction for Model Error Detection in Multiphase Shock Tube Simulation
Authors: Park Chanyoung , Nili Samaun , Mathew Justin T. , Ouellet Frederick , Koneru Rahul , Kim Nam H. , Balachandar Sivaramakrishnan , Haftka Raphael T.
Published: June 2021

Uncertainty quantification (UQ) is an important step in the verification and validation of scientific computing. Validation can be inconclusive when uncertainties are larger than acceptable ranges for both simulation and experiment. Therefore, uncertainty reduction (UR) is important to achieve meaningful validation. A unique approach in this paper is to separate model error from uncertainty such that UR can reveal the model error. This paper aims to share lessons learned from UQ and UR of a horizontal shock tube simulation, whose goal is to validate the particle drag force model for the compressible multiphase flow. First, simulation UQ revealed the inconsistency in simulation predictions due to the numerical flux scheme, which was clearly shown using the parametric design of experiments. By improving the numerical flux scheme, the uncertainty due to inconsistency was removed, while increasing the overall prediction error. Second, the mismatch between the geometry of the experiments and the simplified 1D simulation model was identified as a lack of knowledge. After modifying simulation conditions and experiments, it turned out that the error due to the mismatch was small, which was unexpected based on expert opinions. Last, the uncertainty in the initial volume fraction of particles was reduced based on rigorous UQ. All these UR measures worked together to reveal the hidden modeling error in the simulation predictions, which can lead to a model improvement in the future. We summarized the lessons learned from this exercise in terms of empty success, useful failure, and deceptive success.
A Study of Influences of Inlet Total Pressure Distortions on Clearance Flow in an Axial Compressor
Authors: Zhu Guoming , Liu Xiaolan , Yang Bo , Song Moru
Published: June 2021

The rotating distortion generated by upstream wakes or low speed flow cells is a kind of phenomenon in the inlet of middle and rear stages of an axial compressor. Highly complex inflow can obviously affect the performance and the stability of these stages, and is needed to be considered during compressor design. In this paper, a series of unsteady computational fluid dynamics (CFD) simulations is conducted based on a model of a 1-1/2 stage axial compressor to investigate the effects of the distorted inflows near the casing on the compressor performance and the clearance flow. Detailed analysis of the flow field has been performed and interesting results are concluded. The distortions, such as total pressure distortion in circumferential and radial directions, can block the tip region so that the separation loss and the mixing loss in this area are increased, and the efficiency and the total pressure ratio are dropped correspondingly. Besides, the distortions can change the static pressure distribution near the leading edge of the rotor, and make the clearance flow spill out of the rotor edge more easily under near stall (NS) condition, especially in the cases with corotating distortions. This phenomenon can be used to explain why the stall margin is deteriorated with nonuniform inflows.
The Influence of Needle Eccentric Motion on Hole-to-Hole Injection Characteristics of a Two-Layered Eight-Hole Diesel Injector
Authors: Jin Tianyu , Sun Yu , Wang Chuqiao , Moro Adams , Wu Xiwen , Luo Fuqiang
Published: June 2021

The stringent emission regulations diesel engines are required to meet have resulted in the usage of multihole and ultramultihole injectors, nowadays. In this research study, a double-layered eight-hole diesel injection nozzle was investigated both numerically and experimentally. A three-dimensional model of the nozzle which was validated with experimental results was used to analyze the injection characteristics of each hole. The validation was conducted by comparing experiment and simulation injection rate results, acquired simultaneously from all the holes of the injector and the model. The fuel flow rates of the lower layered holes are higher than those of the upper layered holes. Two different needle eccentricity models were established. The first model only included the lateral displacement of the needle during needle lift. The needle reached maximum displacement at full needle lift. The second model considered the needle inelastic deformation into consideration. The needle radially displaces and glides along with the needle seat surface during needle lift. When the eccentricity reached a maximum in the radial direction, the needle began to lift upward vertically. The differences in injection characteristics under the different eccentricity models were apparent. The results indicated that the cycle injection quantity, fuel injection rate, and cavitation of each hole were affected during the initial lifting stages of the needle lift. As the eccentricity of the needle increases, the injection rate uniformity from the nozzle hole deteriorates. The result showed that the upper layered holes were affected by the needle eccentricity during needle lift.
Experimental Results of Local Shear Stresses and Friction Torque in an Open Rotor-Stator Disk System
Authors: Kuntze Alexander , Odenbach Stefan , Uffrecht Wieland
Published: June 2021

This contribution presents experimental investigations of friction torque in an open rotor–stator disk system by using two different measuring procedures. The first procedure is based on a thermo electrical wall shear stress sensor. The sensor is investigated in two different substrates and different measuring parameters. A thermal model consisting of the supplied heating power, the thermal resistance toward the fluid, and into the substrate as well as the over temperature is used to achieve the heat transfer coefficient on the sensor surface. This heat transfer coefficient is attributed by a functional relationship to the wall shear stress. This relationship is first calibrated in a rectangular channel and subsequently validated at a fully turbulent flat plat flow. The second measuring procedure based on the tangential displacement of the stator disk due the friction torque. The disk is attached at a torsion spring. The friction torque is achieved by the torsion spring constant and the tangential displacement of the stator disk. Both measuring procedures are compared and agree well with each other. The used test rig has the possibility of reaching rotational Reynolds numbers representative, for instance, of a modern gas turbine. The investigations were carried out by a 0.5 m diameter rotor disk rotating up to 8500 rpm with a gap ratio between 0.008 and 0.04. The friction torque is measured on the stator disk and can be converted into moment coefficient. Moment coefficient on stator and measured pressure distributions are presented for different gap ratios and rotational Reynolds number.
Comparative Analysis of the 16S to 23S Ribosomal Intergenic Spacer Sequences of Bacillus thuringiensis Strains and Subspecies and of Closely Related Species
Authors: Bourque S N , Valero J R , Lavoie M C , Levesque R C
Published: June 2021

Volume 61, no. 4, p. 1624, column 2, lines 38-41: The sentence should read "For example, at position 21, the G nucleotide (Fig. 1) was present in all the ISR B. thuringiensis subspecies except for B. thuringiensis subsp. tenebrionis (Te4), which contained an A." Page 1624, column 2, line 45: "Position 62" should read "position 11." Page 1624, column 2, line 47: "Position 90" should read "position 39." Page 1624, column 2, line 49: "Position 83" should read "position 32." Page 1625, column 1, line 3: "Position 83" should read "position 32." Page 1626, column 1, line 1: "Positions 62, 90, and 165, and one deletion at position 83" should read "positions 11, 39, and 114, and one deletion at position 32." [This corrects the article on p. 1623 in vol. 61.].
Modification of the gas-liquid chromatography procedure and evaluation of a new column packing material for the identification of anaerobic bacteria
Authors: Hauser K J , Zabransky R J
Published: June 2021

Gas-liquid chromatography has become a useful aid for the identification of anaerobic bacteria in the clinical laboratory. When many extracted samples are to be analyzed, time is of prime importance. By altering the operating conditions of the chromatograph, we have decreased the total elution time of the volatile fatty acids examined to approximately 12 min. There is, however, a decrease in the ability to resolve propionic and isobutyric acids. A new column packing material, SP-1220 (Supelco), was found to give excellent separation of propionic and isobutyric acids as well as demonstrating the presence of formic acid which was not seen with the previously used Resoflex. Extracts of clinical isolates of anaerobic organisms were processed using the altered conditions and new column packing material with excellent resolution of all acids. The use of SP-1220 in the clinical laboratory will facilitate the identification of anaerobic bacteria.
Pluronic polyols in human lymphocyte cell line cultures
Authors: Mizrahi A
Published: June 2021

Pluronic polyols markedly improved the growth of two human lymphocyte cell lines when added to the growth medium in concentrations of 0.05 to 0.1%. The results of the current studies suggest that, in addition to the protective effect of polyols against mechanical damage of mammalian cells in submerged cultures, the pluronic compounds may also, by lowering surface tension, facilitate transport of metabolites into cells and thus increase the growth rate.
Uracil and pyruvate requirements of anaerobic growth of staphylococci
Authors: Evans J B
Published: June 2021

Sixty-six strains of staphylococci recently isolated from human skin and identified as members of the three recognized species of staphylococci, and 21 stock strains representing most of the Baird-Parker subgroups of staphylococci and micrococci were studied. All 16 skin strains of Staphylococcus aureus demonstrated weak to moderate anaerobic growth in the basal medium, growth stimulation by either uracil or pyruvate, and best growth when both were added. The 20 skin strains of S. epidermidis responded similarly to S. aureus but with a tendency toward heavier growth. The 28 isolates of S. saprophyticus generally gave little or no growth in the basal medium, no increase due to pyruvate alone, a weak response to uracil alone, and, with three exceptions, gave moderate to good growth when both supplements were present. The Baird-Parker strains from subgroups S-II and S-III responded like S. epidermidis; those from subgroups S-V, S-VI, M-1, M-2, M-3, and M-6 generally responded like S. saprophyticus; and those from subgroups M-4 and M-5 failed to grow anaerobically in all media.
Recovery of yeast from vented blood culture bottles
Authors: Roberts G D , Horstmeier C , Hall M , Washington J A
Published: June 2021

Rates of isolation of yeasts from blood cultures were significantly enhanced by venting vacuum blood culture bottles in studies of both stimulated and patients' blood cultures; however, the time interval to detection of positivity of yeasts in the clinical studies was significantly (P less than 0.01) shorter in a vented bottle with biphasic brain heart infusion medium than in a vented bottle with soybean-casein digest broth. The mean time intervals to detection of positivity were 2.6 days in the former and 5.2 days in the latter.
Rapid methods for identification of yeasts
Authors: Huppert M , Harper G , Sun S H , Delanerolle V
Published: June 2021

Opportunistic infections by yeasts have been implicated as one of the major causes of complications in the compromised patient. Rapid recognition and identification of these yeasts is essential for patient management, but conventional liquid medium methods for completing identification tests are cumbersome and time consuming. Rapid tests have been devised based on modifications of methods commonly used in bacteriology. These rapid methods included tests for carbohydrate and nitrate assimilation, fermentation, and urease production. These were compared with several current methods for accuracy of results, for time to final identification, and for economy of time and reagents. In addition, the usual tests for pseudogerm tube formation, for production of hyphae or pseudohyphae, and for growth temperatures were included. The rapid tests achieved 96% or better accuracy compared with expected results, and 46 species of yeasts were identified in 1 to 2 days compared with the 10 to 14 days required by conventional liquid culture methods.
Demonstration of the capsular antigens of bovine group B streptococci by the serum-soft agar method
Authors: Kane J A , Rabkin A E , Karakawa W W
Published: June 2021

The elaboration of type-specific capsular antigens by group B streptococci can be demonstrated by the serum-soft agar technique. Group B streptococci isolated from bovine mastitis, namely, strains 9F, 14Mi, 8Mo, 44B, and 4S, were shown to form diffuse and compact types of colony morphology in serum-soft agar. Immunochemical and chemical analyses of antigens isolated from diffuse and compact colonies of strain 9F indicated that the diffuse-type growth of this strain was due to the elaboration of a galactose-rich surface antigen, whereas the compact 9F strain was devoid of this antigen. Specific 9F antiserum was effective in converting the diffuse 9F colonies of the compact type, indicating the presence of capsular material. Preliminary evidence suggests that the serum-soft agar technique could also be used to determine the antigenic diversity of the surface antigens of group B streptococci, thus providing an effective means of typing those organisms.
Evaluation of cellular substrates for antinuclear antibody determinations
Authors: Hahon N , Eckert H L , Stewart J
Published: June 2021

The immunofluorescent technique was employed to evaluate the sensitivity of 10 human and animal cell monolayers and tissue sections as substrates for titering the antinuclear antibody content of serum samples. The highest mean ranks of sensitivity, the relative ability of each substrate to maintain its sensitivity rank when 21 selected positive sera were tested, were achieved by two fibroblast cell lines, baby hamster kidney (BHK 21/C13) and human lung (WI-38), respectively. The least sensitive substrates were commercial rat kidney and liver tissue sections.
Adaptation of plastic surfaces for tissue culture by glow discharge
Authors: Amstein C F , Hartman P A
Published: June 2021

Plastic petri dishes and microtitration plates were electrically charged by a glow discharge unit installed in a vacuum evaporator. Charged and uncharged plates, as well as plates commercially treated for tissue culture, were inoculated with Vero and BHK-21 cell lines; secondary cultures of monkey kidney, chicken lung, canine kidney, and embryonic bovine kidney; and primary chicken embryo fibroblasts and chicken lung cells. All cell cultures grew normally on petri plates charged with the covers open. Growth rate and cell density compared favorably with growth on the commercial tissue culture plates; cell growth was somewhat less dense, however, on plates charged with the covers closed. Charged plates could be sterilized by ultraviolet light and ethylene oxide with no adverse effects on cell growth. Cells inoculated onto plates charged up to 7 months before inoculation grew as well as on freshly charged plates.
Unclassified, Lactose-Fermenting, Urease-Producing Member of the Family
Enterobacteriaceae
Resembling
Escherichia coli
Authors: Washington John A. , Maker Myron D.
Published: June 2021

Eight strains of an unclassified, oxidase-negative, lactose-fermenting, urease-producing, gram-negative bacillus were isolated from clinical material. With the exception of urease production, the biochemical characteristics of these organisms resembled those of
Escherichia coli
.
A simple carbohydrate fermentation test for identification of the pathogenic Neisseria
Authors: Reddick A
Published: June 2021

The carbohydrate fermentation test in cystine-Trypticase agar-tubed medium was compared with the Minitek system with carbohydrate-impregnated paper disks in Müeller-Hinton broth for identification of Neisseria gonorrhoeae and N. meningitidis. There was 100% agreement between the methods for confirmation of N. meningitidis. The paper disk method confirmed 98% of the N. gonorrhoeae isolates; the cystine-Trypticase agar method confirmed 96%. Reactions with the paper disk method could be read in 4 h.
Evaluation of
Aspergillus
Differential Medium
Authors: Salkin I. F. , Gordon M. A.
Published: June 2021

The new
Aspergillus
differential medium distinguishes effectively between members of the
Aspergillus flavus
group and other
Aspergillus
species of interest in medical mycology.
Comparison of the reversed passive hemagglutination with radioimmunoassay methods for hepatitis B antigen
Authors: Leers W D , Kouroupis G M
Published: June 2021

Radioimmunoassay for the detection of hepatitis B antigen has been accepted in many diagnostic laboratories now. The question of nonspecific positives has always been a matter of controversy. Two improved radioimmunoassay tests, namely Ausria II-125 by Abbott Laboratories and a radioimmunoassay method by Connaught Laboratories Limited (Hebria), were compared with the original Ausria 125I. Included in the comparison was the reversed passive hemagglutination test (Auscell, Abbott). Five hundred sera of clinical patients were tested. Fifty-five or 11% were found to have hepatitis B antigen. Three tests, Ausria 125I, Ausria II-125, and Hebria showed the same number of positive sera, whereas Auscell missed one. However, Ausria 125I indicated two additional false positives. Dilution experiments, however, indicated that Ausria II-125 and Hebria were the most sensitive tests, with the reversed passive hemaglutination showing the least sensitivity. Therefore, the new Ausria II-125 and the Hebria radioimmunoassay tests are preferable in view of their sensitivity and specificity.
Identification of
Propionibacterium acnes
and Related Organisms by Precipitin Tests with Trichloroacetic Acid Extracts
Authors: Cummins C. S.
Published: June 2021

The serological identification of
Propionibacterium acnes, P. granulosum
, and
P. avidum
, using trichloroacetic acid extracts, is described. With antisera prepared against reference strains, the method has been tested on 142 strains recently isolated from human skin. All except two of the strains could be identified serologically, and there was excellent agreement between the serological results and the fermentation pattern of the strains. Two serological types of
P. acnes
and two of
P. avidum
were identified, but only one of
P. granulosum.
Demonstration of
Rickettsia rickettsii
in the Rhesus Monkey by Immune Fluorescence Microscopy
Authors: Pedersen Carl E. , Bagley Lauren R. , Kenyon Richard H. , Sammons Lenora S. , Burger Gary T.
Published: June 2021

Indirect immune fluorescence was used to detect rickettsiae in the tissues of a primate inoculated subcutaneously with
Rickettsia rickettsii.
Rickettsiae were identified by indirect immune fluorescence predominantly in skin, skeletal muscle, scrotum, testicles, nares, heart, kidney, liver, brain, spleen, pancreas, and larynx. Cell culture assay confirmed the presence of infectious organisms in those specimens.
Improvements of a Radioimmunoassay for Measurement of Viral Antibody in Human Sera
Authors: Patterson William R. , Smith Kendall O.
Published: June 2021

Modifications were made which increased the sensitivity of a solid-phase radioimmunoassay for serum antibody to human herpesviruses. Quantitation of antibody can be accomplished by referring to standard curve titrations.
Clinical Laboratory Evaluation of the Further Improved Enterotube and Encise II
Authors: Isenberg Henry D. , Scherber Jane S. , Cosgrove Jeanne O.
Published: June 2021

The most recent improvements in the Enterotube coupled with Encise II permitted identification of routinely and abnormally reacting members of the family
Enterobacteriaceae
.
Retention of Preservative Levels of Formaldehyde in Desiccated Biological Products
Authors: Pemberton John R.
Published: June 2021

Concentrations ranging from 8 to 100% of the preservative level of formalin (37% formaldehyde solution) were retained by desiccated biologics, with most products retaining about 50% regardless of the amount originally present.
Comparison of Immunodiffusion and Complement Fixation Tests in the Diagnosis of Histoplasmosis
Authors: Bauman David S. , Smith Coy D.
Published: June 2021

The immunodiffusion and complement fixation tests for histoplasmosis were compared on 2,090 initial sera from 70 proven cases of histoplasmosis, 177 routine chest hospital patients, and 1,843 coal miners from outside the major endemic area for histoplasmosis. The complement fixation test using histoplasmin as antigen detected antibodies in the sera of 72.8% of the 70 proven cases, while the complement fixation test using yeast antigen detected antibodies in 94.3% of the case sera, and the immunodiffusion test using histoplasmin antigen detected antibodies in 90% of the sera. The tests were also compared for sensitivity, specificity, and ease of performance.
Rapid Diagnosis of Mumps Virus Infections by Immunofluorescence Methods
Authors: Lennette David A. , Emmons Richard W. , Lennette Edwin H.
Published: June 2021

Mumps and its complications, particularly meningoencephalitis, is an important disease problem, and more rapid diagnostic methods are desirable. A study was made of immunofluorescence methods for the early detection of mumps virus isolated in cell cultures, or adsorbed directly from clinical specimens onto guinea pig erythrocytes. A specific diagnosis could be made in hours to 2 or 3 days utilizing immunofluorescence methods, in contrast to about 6 days by standard methods. Details of the direct immunofluorescence methods are presented, to encourage wider application in clinical virology laboratories.
Effect of Glass on pH-Dependent Stability of Typhoid Vaccine
Authors: Driesens Robert J.
Published: June 2021

Vaccines made from the Ty-2 strain of
Salmonella typhosa
were tested periodically for stability of pH and of potency. The acetone-treated cultures prepared in buffered saline solutions retained potency beyond 30 months of storage at 0 to 5 C. Similar vaccines in unbuffered saline solutions lost potency coincident with increase of alkalinity. Vaccines packaged in United States Pharmacopeia borosilicate glass vials retained potency and pH stability, whereas those in Type III United States Pharmacopeia soda-lime glass vials were less stable.
Sero-Epidemiological Study on Equine Influenza in Japan
Authors: Goto Hitoshi , Shimizu Kiheiji , Abe Takemaru , Kanamitsu Masatsugu
Published: June 2021

A serological survey was conducted on horse sera collected for 7 years just before the first outbreak of equine influenza (EI) infection in Japan in 1971. No antibodies against the A/Equi-1/Prague/56 (equi-1) and A/Equi-2/Miami/63 (equi-2) strains of EI virus were detected in any of the sera of 452 native horses when employing hemagglutination inhibition (HI) and complement fixation (CF) tests against viral (V) antigen. On the contrary, of the 80 imported horses, 48 (60.0%) had HI titers of 1:8 or higher against equi-1 and 23 (28.8%) against equi-2. In the CF-V test 42.6% of the horses showed titers of 1:4 or higher against equi-1 antigen and 42.9% against equi-2 antigen. However, all the test sera of the native and imported horses were negative (less than 1:4) in CF tests against soluble human influenza antigen. Epidemiological analysis was carried out to clarify the relationship between the history and the presence of serum antibody against EI viruses in individual imported horses.
Six-Hour Pigmentation Test for the Identification of
Cryptococcus neoformans
Authors: Hopfer Roy L. , Gröschel Dieter
Published: June 2021

Cryptococcus neoformans
colonies can be identified within 6 h using paper disks containing caffeic acid and ferric citrate. Indentification is based on the development of a dark brown pigment. Saprophytic
Cryptococcus
species and common clinically isolated yeasts do not develop the brown color. The concentration of the reagents and the method of storage of the impregnated paper disks are critical for the rapid and specific development of the pigment.
Clinical Laboratory Evaluation of the Fifty-Milliliter Vacutainer Blood Culture Tube
Authors: Painter Barbara G. , Isenberg Henry D.
Published: June 2021

The efficacy of the 50-ml vacutainer culture tube (Becton-Dickinson) for recovery of microorganisms from blood cultures was compared with laboratory-prepared blood culture media. The isolation of
Bacteroides
sp. was significantly higher in the 50-ml vacutainer culture tube whereas that of nonfermenting gram-negative rods and yeasts was higher in the in-house media. There was no significant difference in the recovery of all other organisms.
Analysis of acetoin and diacetyl in bacterial culture supernatants by gas-liquid chromatography
Authors: Lee S M , Drucker D B
Published: June 2021

The acetoin and diacetyl contents of culture supernatants of Voges-Proskauer-positive "viridans" streptotocci, Klebsiella pneumoniae and Staphylococcus aureus, were determined by a gas liquid chromatographic procedure, in which supernatants were extracted with diethyl ether and diacetyl was measured on columns of 10% (wt/wt) polyethylene glycol 400 (PEG 400) at 73 C. Acetoin was converted to diacetyl, before analysis, by a simple oxidation procedure with ferric chloride and without a distillation step. Streptococcal culture supernatants were shown by this method to contain only acetoin; supernatants of K. pneumoniae and S. aureus contained both acetoin and diacetyl.
Naturally occurring and experimentally induced mycoplasmal arthritis of cattle
Authors: Stalheim O H , Page L A
Published: June 2021

Mycoplasma agalactiae subsp. bovis strain Iowa 1136 was isolated from synovial fluids of a clinical case of arthritis in cattle on pasture in Iowa. When given to calves and cows by intra-articular or intravenous injection, it caused severe and persistent joint infections with fever, lameness, and swelling of the affected joints, plus synovitis, tendonitis, and fibrinous-purulent synovial fluids of high protein content. Intramammary administration of the organism caused severe mastitis. Calves nursing the cows developed severe mycoplasmal arthritis.
Application of counterimmunoelectrophoresis in the identification of Streptococcus pneumoniae in clinical isolates
Authors: Sottile M I , Rytel M W
Published: June 2021

The use of counterimmunoelectrophoresis (CIE) as a diagnostic tool in infectious diseases is becoming more widespread. This study was undertaken to determine the possible use of CIE in the more rapid identification of Streptococcus pneumoniae in clinical isolates. Typing sera were obtained from the Statens Seruminstitut, Denmark. Sixty-seven out of 68 pneumococcal isolates that were optochin sensitive and bile soluble were typed by CIE. One isolate was nontypable even after mouse passage. An additional three isolates that were optochin resistant were considered to be pneumococci on the basis of the bile solubility test and their typability by CIE. Seventy-seven alpha-streptococci were tested for the presence of cross-reacting capsular antigens. Fifty-three alpha-streptococci showed no cross-reactions using the omniserum. Precipitin bands were obtained with the omniserum with 10 of the isolates, but these did not react with type-specific antisera. However, 14 isolates did react with the type-specific pneumococcal antisera. The sensitivity of the test was increased by sonicating whole-cell suspensions before electrophoresis was carried out. Mueller-Hinton broths were inoculated with presumptive pneumococcal colonies that formed the predominant or only colony type on primary blood agar plates. These cultures required a 4-h incubation period with an initial inoculum of 10(6) viable organisms/ml before a precipitin band could be detected. Precipitin bands were observed in 54 out of 56 (97%) broth cultures of pneumococci that had been incubated for 4 h at 37 C. These data suggest that CIE could be a useful tool in the identification of S. pneumoniae isolated from clinical specimens.
Isolation of
Neisseria meningitidis
from the Genito-Urinary Tract and Anal Canal
Authors: Faur Yvonne C. , Weisburd Martin H. , Wilson Marion E.
Published: June 2021

During the first 3 months of 1975, a striking increase has been noted in the incidence of
Neisseria meningitidis
in cultures from the genito-urinary tract and anal canal of both males and females being screened for gonorrhea. The data for recovery of these organisms from these sites are presented and reviewed.
Evaluation of the enteric analyzer for identification of Enterobacteriaceae
Authors: Shayegani M , Hubbard M E , Hiscott T , McGlynn D M , Yewdall R C
Published: June 2021

The reliability of the Enteric Analyzer for identification of Enterobacteriaceae was evaluated using biochemical results previously obtained for 291 organisms with the conventional, R/B, and Minitek systems. The instrument correctly identified 77.3% of the organisms using conventional system results, 74.2% using R/B results, and 60.5% using Minitek results. The low rate of identification with the conventional system occurs primarily because the instrument is not programmed to consider delayed biochemical reactions. The arbitrary use of 90% and 99% probabilities for test reactions also contributes to a lower percentage of identification. The Enteric Analyzer does not replace the judgment of experienced personnel in the identification of atypical bacteria, but it may prove helpful in speeding up final computer identification of typical microorganisms.
Laboratory studies of Venezuelan equine encephalitis virus in equines, Texas, 1971
Authors: Calisher C H , Maness K S
Published: June 2021

During the summer and fall of 1971, epizootic and epidemic Venezuelan equine encephalitis was detected in Texas. Isolates of epizootic (IB) and vaccine (TC-83) strains were distinguished by virulence of the former for guinea pigs. Vaccine virus was isolated from 1 to 14 days after vaccination and neutralization tests demonstrated the appearance of antibody about a week after vaccination. Viremia titers of subtype IB in horses ranged from 2.2 to 8.3 log10 suckling mouse intracranial 50% lethal doses per ml. Of 101 equines from which Venezuelan equine encephalitis virus (IB or TC-83) strains were isolated, 87 had no neutralizing antibody against Venezuelan, eastern or western equine encephalitis viruses.
Evaluation of an indirect hemagglutination test for the diagnosis of human leptospirosis
Authors: Sulzer C R , Glosser J W , Rogers F , Jones W L , Frix M
Published: June 2021

A presumptive hemagglutination test for the serological diagnosis of leptospirosis in humans is described. The antigen was prepared from a soluble alcohol extract of an andamana strain sorbed to human O-negative erythrocytes and preserved by pyruvic aldehyde fixation. In this study, the overall sensitivity of the hemagglutination test was 92% in contrast to 69% for the presumptive slide agglutination test. The specificity was 95% for the hemagglutination test in comparison with 83% for the slide test.
Evaluation of antibody coating of yeasts in urine as an indicator of the site of urinary tract infection
Authors: Harding S A , Merz W G
Published: June 2021

Antibody coating of yeasts (Candida sp. and Torulopsis sp.) found in urine specimens was investigated to ascertain whether the presence of such coating might identify the site of urinary tract infection. Washed yeast cells obtained by centrifugation of fresh urine specimens were reacted with fluorescein-conjugated goat antihuman immunoglobulins (Ig) G, A, and M and examined by fluorescent microscopy. IgG was found on the surface of all species of yeast encountered in all urine specimens evaluted, whereas there was variability of IgA AND IgM coating. Antibody coating with IgG, IgA, AND IgM was also demonstrated on yeasts from other body sites (sputum, gastrostomy, oral, etc.). Control experiments confirmed the specificity of the reactions. Thus, it appears that yeasts from any body site are coated with antibodies. These results are in contrast to recent work with bacteria which showed that the presence of antibody-coated (IgG) bacteria indicates upper urinary tract infection (pyelonephritis) while bacteria are not coated with antibodies in lower urinary tract infection. Since all yeasts from all body sites tested were found to be coated with antibody regardless of the clinical situation, the presence of surface antibody has no diagnostic value in identifying the site of urinary tract infection with yeasts.
Prevalence of Mycoplasma hominis and Ureaplasma urealyticum (T strains) in urine of adolescents
Authors: Foy H , Kenny G , Bor E , Hammar S , Hickman R
Published: June 2021

Adolescent children were surveyed for colonization with Mycoplasma hominis and Ureaplasma urealyticum by culturing urine specimens. Rates were compared between three study groups: (i) 397 children attending parochial schools, (ii) 293 children attending an adolescent clinic specializing in adjustment problems, and (iii) 86 children attending a renal clinic. The recovery rate was higher among postpubertal girls attending the renal clinic (33%) and the adolescent clinic (26%) than among students attending parochial high school (males 2%, females 8%). Girls had approximately eightfold higher rates than boys of the same age. Isolation of Mycoplasmataceae was associated with certain sociological determinants, such as dating, cigarette smoking, and coming from a broken home, but also with abnormal findings (protein, leucocytes) in urine.
Modified counterelectrophoresis method for subtyping hepatitis B antigen
Authors: Hatch M H
Published: June 2021

A modified counterelectrophoresis (CEP) method was developed for determining the d and y subtypes of hepatitis B antigen (HBSAg). In this method, HBSAg of known subtype was diffused into the agarose gel before electrophoresis from the wells which were subsequently to receive the subtyping antiserum. This served to absorb the common anti-alpha antibody from the subtyping antiserum, which was heterologous with respect to the d or y component, during electrophoresis. The remaining d or y antibody then reacted type specifically with the antigen to be subtyped. The modified CEP method was much more sensitive than the immunodiffusion (ID) method for subtyping HBSAg. Sixty-two sera which could not be subtyped by ID were successfully subtyped by the CEP method. The geometric mean HBSAg complement fixation titer determined on 48 of these sera was significantly lower (P congruent to 0.016) than that of a group of sera which could be subtyped by ID. Sixteen other sera could not be subtyped by either the CEP or the ID procedure (geometric mean titer equal to 5.2). Therefore, more sensitive means of subtyping must be used for some HBSAg-positive sera.
Evaluation of the Enteric Analyzer, an instrument to aid in the identification of Enterobacteriaceae
Authors: Brenner D J , Balows A
Published: June 2021

This study evaluated the Enteric Analyzer, an instrument designed to identify Enterobacteriaceae, with data obtained from the Modified r/b Enteric Differential System, other rapid identification systems, or conventional identification systems. It is programmed for 19 reactions with data obtained from Center for Disease Control publications. The instrument is very simple to use. Typical strains from 25 of 28 species were unequivocally identified. With the other three species, two choices were given. A switch allows the user to identify all species possibilities where a given biochemical pattern occurs in more than 1% of the strains or more than 10% of the strains. The instrument is useful both in the clinical laboratory and for teaching purposes.
Motility-indole-lysine medium for presumptive identification of enteric pathogens of Enterobacteriaceae
Authors: Reller L B , Mirrett S
Published: June 2021

Detection of lysine decarboxylase activity is a useful supplement to reactions on triple sugar-iron (TSI) and urea agars in the initial examination of suspected pathogenic isolates from fecal cultures. Owing to the added value of motility and indole production in the differentiation of enteric pathogens, we prepared and evaluated a motility-indole-lysine (MIL) medium. The following 890 organisms were tested: 264 Shigella, 2 Edwardsiella, 182 Salmonella enteritidis, 235 S. typhi, 3 Arizona, 32 Yersinia enterocolitica, and 172 other members of the family Enterobacteriaceae. With few exceptions the MIL medium gave the same results as the standard motility, indole, and lysine decarboxylase (Moeller) test media. All discrepancies were with the indole reaction, which was weak in 2 of 67 strains of Escherichia coli and falsely negative in 6 of 32 strains of Y. enterocolitica. When both TSI agar and lysine-iron agar (LIA) slants are used in the evaluation isolates from fecal cultures, detection of H2S is duplicated. Both LIA and MIL medium detect lysine decarboxylase and deaminase activity equally well. Because of its ability to detect motility and indole production, the MIL medium is more useful than LIA when used with TSI agar. The combination of TSI agar, MIL medium, and urea agar enables reliable initial recognition of enteric pathogens of the Enterobacteriaceae.
New method for the removal of extraneous proteins from purified oncornaviruses
Authors: Traul K , Larson D , Stephens R , Wolff J , Munch K , Mayyasi S
Published: June 2021

Conventional methods (i.e. gradient centrifugation) for the purification of oncornaviruses are usually not effective in complete removal of nonviral proteins. Such contaminants often prove to be a nuisance in subsequent immunological or biochemical studies. Hyperimmune sera prepared from these viruses must be absorbed to assure specificity; cell-derived proteins can be shown to interfere with studies of virus structural proteins, nucleic acids, or viral enzymes. Herein is described a method for removal of most of these contaminants. Viruses are diluted in a high concentration of NaCl to achieve a final concentration of 15%, incubated for 30 min, sedimented, and resuspended in buffer. This procedure results in reductions of up to 48% of the protein without affecting particle count. Immunological, biochemical, and biological properties are not adversely affected. Of the proteins removed, fetal calf serum components and a ribonuclease (presumably cell-derived) were identified. This technique differs significantly from other high-salt methods in that the virus is not precipitated from suspension. It is believed that absorbed proteins are desorbed and left in solution (or suspension) as the virus is sedimented by centrifugation.
Detection of fungi in clinical specimens by phase-contrast microscopy
Authors: Roberts G D
Published: June 2021

During 1973 and 1974, the following fungi were detected in clinical specimens by using phase-contrast microscopy: Blastomyces dermatitidis, 5; Coccidioides immitis, 3; Cryptococcus neoformans, 11; other yeasts 918; dermatophytes, 863; Mucor species, 1; and Aspergillus fumigatus, 16. This technique allows rapid detection and, in many instances, immediate identification of fungi in clinical specimens.
Motility-indole-lysine-sulfide medium
Authors: Ederer G M , Lund M E , Blazevic D J , Reller L B , Mirrett S
Published: June 2021

A medium designed for the detection of motility, indole, lysine decarboxylase and deaminase reactions, and H2S production was devised and evaluated. Results, using 157 strains of enteric pathogens, were in agreement with reference methods. When 300 isolates from fecal cultures were screened using this medium, Shigella was easily differentiated from Escherichia and more of the Proteus species, especially P. morganii, could be eliminated from further study.
Optimal Cooling and Warming Rates in the Preservation of Herpes Simplex Virus (Type 2)
Authors: Ash Ronald J. , Barnhart E. R.
Published: June 2021

Fast rates of cooling and warming were optimal for survival of herpes simplex virus, type 2. Under these conditions cryoprotectants were not necessary for virus preservation.
Obligately Anaerobic Strains of
Corynebacterium vaginale (Haemophilus vaginalis)
Authors: Malone Beatrice H. , Schreiber Minnie , Schneider Nathan J. , Holdeman Lillian V.
Published: June 2021

Six obligately anaerobic strains of
Corynebacterium vaginale (Haemophilus vaginalis)
have been isolated and their characteristics studied. The reactions of the anaerobic strains, as well as of facultative strains tested under anaerobic conditions, are similar to the reactions previously reported for this species.
New technique for quantitative bacteriological sampling of wounds by velvet pads: clinical sampling trial
Authors: Raahave D
Published: June 2021

A new surface sampling method, the velvet pad rinse technique, was compared with the velvet pad imprint method, in a randomized bacteriological sampling trial, using surgical wounds to evaluate quantitative results. The efficiency of bacterial recovery was increased 20-fold by the new technique, and the improvement was ascribed in particular to the introduction of a procedure of rinsing the velvet pad after sampling.
Production of influenza virus complement-fixing antibody in mouse ascitic fluid
Authors: White L A , Gamble W C , Chappell W A
Published: June 2021

Suspension cultures of BHK-21/13s cells infected with either A/Hong Kong/8/68 or B/Massachusetts/3/66 strains of influenza were used to prepare type-specific influenza ribonucleoprotein-immunizing antigens. These antigens were used in comparing four immunization schedules in the production of immune mouse ascitic fluids. Large volumes of ascitic fluids were obtained by these schedules. These fluids contained type-specific complement-fixing antibody and were devoid of nonspecific host tissue or heterologous cross-reactions.
Comparison of three rocky mountain spotted fever vaccines
Authors: Kenyon R H , Sammons L S , Pedersen C E
Published: June 2021

Growth of Rocky Mountain spotted fever (RMSF) rickettsiae in duck embryo cell (DEC) cultures and chicken embryo cell (CEC) cultures was evaluated. Experimental lots of duck embryo cell- and chicken embryo cell-grown Rocky Mountain spotted fever vaccines and a commercial lot of yolk sac-grown vaccine were compared for protective efficacy in rhesus monkeys. Incidence and magnitude of antibody response, febrile response, and rickettsemia, as well as incidence of fatalities, suggested that both cell culture-derived vaccines were more immunogenic than the yolk sac-grown vaccine.