bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of three tests for the serological diagnosis of lymphocytic choriomeningitis virus infection
Authors: Lewis V J , Walter P D , Thacker W L , Winkler W G
Published: June 2021

Levels of lymphocytic choriomeningitis virus antibody were assayed in 62 infected persons. The three tests used were indirect fluorescent antibody (IFA), complement fixation, and neutralization in mice. The sera first became positive by the IFA test, and IFA titers rapidly rose to a relatively high level, with the sera remaining positive long after the antibody detectable by complement fixation had disappeared. The IFA test appeared to be specific. The sera became positive last by the mouse neutralization test; with this test, antibody first appeared several weeks after infection. Virus-infected cells were stable when stored at -60 C, allowing diagnostic sera to be tested promptly by the IFA test. The IFA test for lymphocytic choriomeningitis antibody should increase the number of serological diagnoses, since it is not only rapid and specific, but detects cases not diagnosed by the other methods.
Improved auxanographic method for yeast assimilations: a comparison with other approaches
Authors: Land G A , Vinton E C , Adcock G B , Hopkins J M
Published: June 2021

An improved pour-plate auxanographic method has been developed for determining the assimilation of 14 different carbohydrates by medically important yeasts. Reduction of a dye incorporated into the agar has been correlated with the growth and carbohydrate assimilation of the yeasts, allowing the speciation of many yeasts within 24 to 48 h. This technique has been found to compare more than favorably with existing yeast assimilation techniques, in terms of rapid identification, total cost, and technician time in preparing and inoculating the plates. The dye pour-plate auxanographic technique provides an easier-to-interpret, rapid, and reproducible method of mycological identification for small clinical laboratories.
Dispersion and cultivation of renal cells after short-term storage of kidneys
Authors: de Oca H M , Malinin T I
Published: June 2021

A new method for the preparation of cell suspensions from human newborn kidneys is described. It involves the use of a mixture of trypsin-ethylenediaminetetraacetic acid and collagenase. The cell yields obtained after tissue dispersion by this method were significantly greater than those obtained after dispersion with either trypsin or ethylenediaminetetraacetic acid alone or in combination. When kidneys were removed 12 h or more postmortem from refrigerated cadavers, higher cell yields were obtained from renal tissue stored overnight at 4 to 6 C in CMRL ATM (Healy and Parker, 1966), as compared to cell yields obtained from kidneys processed immediately upon removal. This observation was confirmed by controlled experiments performed with rabbit kidneys.
Seroagglutination Test for Identification of
Mycobacterium paratuberculosis
Authors: Jarnagin Jerald L. , Champion Margaret L. , Thoen Charles O.
Published: June 2021

Twenty-nine of 30 strains of
Mycobacterium paratuberculosis
isolated from clinical specimens were serologically identified. No cross-reactions were observed with
Mycobacterium avium
serotypes 1, 2, 4, and 8.
Effect of temperature on transport and plating media for enteric pathogens
Authors: Taylor W I , Schelhart D
Published: June 2021

The effect of wide variations in incubation temperatures and long periods of incubation on transport and enrichment broths and plating media was determined by exhaustive analysis of 132 diarrheal stools for salmonellae and shigellae. Homogenized stools were streaked onto eosin methylene blue (EMB), Salmonella-Shigella (SS), and xylose lysine deoxycholate (XLD) agar plates, and into saline, Cary-Blair (CB) transport medium, and Selenite F and gram-negative (GN) enrichment broths. Incubation temperatures were compared at 20 C, 35 C, 40 C and ambient, and over a range of 4 to 52 C for media incubated in an insulated picnic cooler in an auto trunk. At 1, 2, 4, and 7 days the plates were observed, and the broths were subcultured. Each stool was streaked to 12 plates for 48 observations and pickings, and to 48 tubes, subcultured to 192 plates, for a total of 240 observations for pathogens. Analysis of data from 6,246 Salmonella-positive plates showed direct streaking to be most effective after 2 days of incubation, but broths were equally effective at 1 or 2 days. By day 4 many plates were overgrown, and both plates and broths showed diminution of positives by about 10% and at day 7, 19%. The 2,434 Shigella-positive plates were more demanding in all times and temperatures of incubation than salmonellae. Although at day 2 best results were obtained on direct streaking, shigellae die-offs in broths were excessive, with positive declining 23.7% by day 2, 49% by day 4, and 60% by day 7. Direct plating of both pathogens was poor at 20 C with about 48% success, but salmonellae preferred higher temperatures (35 and 40 C), whereas shigellae chose 35 C and ambient, which averaged 28 C for the 10-month study. Temperature was immaterial to salmonellae in broths with ambient slightly better than 35 C, but shigellae preferred 20 C and showed a 50% failure rate at 40 C, ambient being equal to 35 C. The preferential rank of broths in efficacy was GN greater than selenite greater than saline greater than CB greater than direct for salmonellae; for shigellae, GN greater than saline greater than direct greater than CB greater than selenite, with selenite proving to be unsuitable for shigellae. Plating media preferences were XLD greater than EMB greater than SS. Ten of 39 shigellae strains could not be recovered from the selenite and SS media combination, the many replications notwithstanding. The effectiveness of salmonellae and shigellae detection at ambient temperatures in Louisiana during the 10-month study period, as compared to controlled incubation temperatures, indicates that satisfactory enteric bacteriology can be done in warm climates without constant temperature incubators.
Use of immunoglobulin coupled to agarose beads for examining the specificity of conjugates
Authors: Scales R W , Jacobs N F , Skaggs R
Published: June 2021

Preparations of purified immunoglobulins, light chains, and unrelated proteins (used as controls) were covalently linked to agarose beads and used to study the specificity of fluorescein isothiocyanate conjugates. The data demonstrate how these beads can be used to detect immunological and non-immunological reactivity in conjugates. Commercial conjugates, conjugates prepared in this laboratory, and fluorescein-labeled normal immunoglobulins demonstrated high reactivity with control beads unless chromatographed on diethylaminoethyl-cellulose to select for the proper fluorescein-protein ratio. Undesirable immunological reactivity could be demonstrated in commercial conjugates and was shown to be due to anti-light-chain antibody.
Effects of atmosphere of incubation and of routine subcultures on detection of bacteremia in vacuum blood culture bottles
Authors: Harkness J L , Hall M , Ilstrup D M , Washington J A
Published: June 2021

Studies comparing isolation rates of bacteria and yeasts from vented and unvented vacuum blood culture bottles containing soybean-casein digest broth showed significantly more frequent and more rapid recovery of Candida and Pseudomonas from the vented bottle and no other statistically significant differences between the two. Subculture of bottles on the day of their collection was shown to accelerate recovery of 48% of positive cultures by day 1. A second subculture of known positive cultures yielded additional organisms in 1.5% of cultures.
Identification of the elementary bodies of Chlamydia trachomatis in the electron microscope by an indirect immunoferritin technique
Authors: Ashley C R , Richmond S J , Caul E O
Published: June 2021

An indirect immunoferritin (IIF) technique is described for recognizing the elementary bodies (EB) of Chlamydia trachomatis in unsectioned preparations. Both the EB of a genital strain of C. trachomatis grown in irradiated McCoy cells and EB in clinical specimens obtained from patients attending a venereal disease clinic were identified by the IIF test in the electron microscope. Cell culture-grown EB were detected by ferritin staining for up to 4 weeks after the organisms had lost their infectivity for tissue cultures. The IIF test was of comparable sensitivity to isolation methods in detecting chlamydiae in clinical specimens. Other possible applications of the IIF technique are discussed.
Unusual Enterobacteriaceae: lactose-positive Salmonella typhimurium which is endemic in São Paulo, Brazil
Authors: Falcão D P , Trabulsi L R , Hickman F W , Farmer J J
Published: June 2021

Since 1971 a lactose-positive (lac+) Salmonella typhimurium variety Copenhagen has been endemic in the city of Sao Paulo. The strain is a strong lactose fermenter and resembles Escherichia coli on primary plating media and in triple sugar iron agar. Although most isolates of the strain have uniform properties, some have slightly different antigens, antibiograms, phage types, or fermentation patterns. Most isolates have come from stools of infants under 1 year of age and are probably hospital acquired; however, other isolates are probably community acquired. Eighteen other lac+ Salmonella isolated in the United States were also studied. Most of these strains resembled E. coli on primary plates and triple sugar iron agar; thus their identification would pose a problem for most clinical laboratories. A simple procedure for detecting lac+ Salmonella mixed with lac+ E. coli consists of touching 12 colonies in succession with a straight wire and then inoculating a peptone iron agar tube. H2S production is apparent from lac+ Salmonella even if 11 E. coli and one Salmonella colony are picked. If a positive peptone iron agar tube is observed, then individual colonies are tested to rule out other strong H2S producers. The true incidence of lac+ Salmonella is unknown because they are not isolated and identified in most laboratories.
Comparison of the counter-immunoelectrophoresis technique with the Reiter protein and three other serological tests as a first line test for syphilis
Authors: Bänffer J R , Raghoenath S , Hulst A M
Published: June 2021

The counter-immunoelectrophoresis technique with the Reiter protein (RP-CIE) was compared with two complement fixation tests (Kolmer and RPCF) and a flocculation test (VDRL) in sensitivity and specificity. Of the 1,927 consecutive attendants of a venereal disease clinic whose serum samples were used, 250 were considered to be syphilitic. The number of true-positive and false-positive reactions were: 121 and 4 (VDRL), 124 and 2 (Kolmer), 179 and 41 (RPCF), 166 and 16 (RP-CIE). The VDRL and the RPCF combined were more sensitive and less specific than the VDRL combined with the Kolmer. If the RPCF was replaced by the RP-CIE the sensitivity remained the same but the specificity was higher. The RP-CIE scored more positives than the RPCF in untreated cases of primary syphilis. The results argue for substitution of the RP-CIE for the Kolmer in the combination with the VDRL in the serodiagnosis for syphilis. Moreover, the RP-CIE presents the technical advantages of simplicity, speed of performance, and of not being hampered by the anticomplementary nature of the serum sample.
Insolubilized Salmonella lipopolysaccharides as efficient immunoadsorbents for the preparation of specific Salmonella antisera
Authors: Eskenazy M , Strahilov D , Ivanova R , Kalinova R
Published: June 2021

Lipopolysaccharides (LPS) derived from a single Salmonella serotype or a combination of serotypes were submitted to insolubilization by means of glutaraldehyde. Cross-linked LPS proved to be efficient immunoadsorbents. They were employed for the removal of cross-reacting anti-O antibodies from various Salmonella antisera. LPS immunoadsorbents offer a number of advantages over bacterial cells concerning the preparation of specific bacterial antisera: they regain the original antibody binding capacity after tryptic digestion of the anti-LPS antibodies adsorbed and can be repeatedly used (15 times at least), adsorption of the sera is complete within 30 min, and the procedure is simplified. Prolonged storage (over 3 years) has no deleterious effect on the adsorption properties of the immunoadsorbents. Various applications of LPS immunoadsorbents are described.
Rapid separation of immunoglobulin M from immunoglobulin G antibodies for reliable diagnosis of recent rubella infections
Authors: Frisch-Niggemeyer W
Published: June 2021

Chromatography on controlled pore glass was adapted for the separation of immunoglobulin M (IgM) and immunoglobulin G (IgG) rubella antibodies from 0.3-ml samples of human serum. An extremely sharp separation of IgM from IgG antibodies could be obtained within 40 min. Nonspecific inhibitors were removed before chromatography by precipitation with high-molecular-weight dextran sulfate, and the titer of rubella antibodies in the different classes of immunoglobulins were assayed with a modified hemagglutination inhibition technique. The combination of these methods is recommended for routine tests. It permits an accurate diagnosis of recent rubella infection within a few hours.
Epidemiology of Pseudomonas aeruginosa in a general hospital: a four-year study
Authors: Thomas E T , Jones L F , Simão E , Solé-Vernin C , Farmer J J
Published: June 2021

A retrospective study was done to determine the epidemiology of infection and/or colonization due to Pseudomonas aeruginosa in a Brazilian general hospital. In 1966, 1968, and 1969, there were only two instances where probable cross-contamination was shown; the remaining isolates were unrelated. In late 1971 the hospital experienced a marked increase in P. aeruginosa isolation. Contaminated dextrose solutions used in the infant feeding were the apparent cause of the problem which occurred in the premature and special care nurseries. A contaminated oxygen humidifying bottle was the source of a different outbreak in surgery. There was also evidence in four instances that cross-infection and/or contamination had occurred. Pyocin and serological typing revealed that many strains were involved and led to a clear understanding of the complex epidemiological relationships among all the strains.
Responses of isolator-derived Japanese quail and quail cell cultures to selected animal viruses
Authors: Farrow W M , Schmitt M W , Groupé V
Published: June 2021

Thirteen oncogenic and necrotizing animal viruses were assayed in LIFE Sciences, Inc. (LSI)-specific pathogen-free Japanese quail and LSI-specific pathogen-free chicken embryo cell cultures. Nine viruses produced similar titers in the quail and chicken cell systems, whereas four viruses showed significantly higher titers in chickens. Young Japanese quail and chickens were inoculated with five selected avain viruses and maintained in stainless-steel isolators. Comparable responses were noted in quail and chickens injected with Newcastle disease virus and avain leukosis virus, but quail were significantly more resistant than chickens to fowl pox virus, laryngotracheitis virus, and Marek's disease herpesvirus. Although no overt symptoms of disease were observed in Japanese quail inoculated with most avain viruses, neutralizing antibody or virus was detected, indicating presence of an inapparent infection. In one experiment, neutralizing antibody was detected in a comparable number of quail and chickens after inoculation with avian leukosis virus. Avian leukosis virus viremia was observed at 12 and 70 days postinoculation, with the COFAL (complement fixation for avian leukosis) titers similar for quail and chickens. Most quail infected with Marek's disease herpesvirus produced neutralizing antibody within 70 days but showed no classical symptoms of Marek's disease even when held for 5 months. In contrast, all chickens inoculated with Marek's disease herpesvirus died within 20 days. The utility of quail embryo cell cultured in the preparation of vaccines and biological reagents is discussed.
Indirect hemagglutination test for human antibody to typhus and spotted fever group rickettsiae
Authors: Shirai A , Dietel J W , Osterman J V
Published: June 2021

An indirect hemagglutination (IHA) test is described that uses glutaraldehyde-stabilized erythrocytes treated with a rickettsial erythrocyte-sensitizing substance obtained from Rickettsia typhi or Rickettsia rickettsii. The serological reagent was stable for at least 3 months at room temperature and 6 months at 4 C. It exhibited group specificity and no group cross-reactivity. At a minimum dilution of 1:40, acute and early convalescent epidemic and murine typhus antisera showed 86% positive reactors, whereas similar spotted fever antisera had 74% positive reactors. In comparison with the indirect fluorescent antibody test, the IHA procedure gave lower titers but showed comparable detection of seroconversion with most paired sera. The IHA test demonstrated significantly higher titers than the complement fixation test and was more sensitive than either the complement fixation or Weil-Felix test in identifying seroconversion. No agglutination was observed when sensitized erythrocytes were tested with rodent sera known to contain rickettsial antibodies.
Comparison of four culture media for the isolation of Mycobacterium tuberculosis: a 2-year study
Authors: Martin R S , Sumarah R K , Robart E M
Published: June 2021

Four media, Lowenstein-Jensen, Middlebrook, Petragnani, and ribonucleic acid, were tested for comparative ability to detect Mycobacterium tuberculosis. Specimens used included sputum, urine, tissue, and gastric washings. Three types of comparison were used: (i) comparison derived from randomized specimens; (ii) comparison of cultures from newly diagnosed cases that had received no prior therapy; and (iii) comparison of cultures from specimens whose initial direct smears were negative. Overall, ribonucleic acid medium performed best, but the differences among the four media were small.
Longitudinal, serological study of cytomegalovirus infections in nurses and in personnel without patient contact
Authors: Yeager A S
Published: June 2021

Sera were obtained at intervals from 172 hospital employees for measurement of cytomegalovirus (CMV) complement fixation (CF) and indirect hemagglutination antibody. No fourfold rises or falls in titer were seen over a 19- to 27-month period among 71 employees with initially positive CMV CF titers. The concurrence rate between the CMV CF and the indirect hemagglutination antibody tests in identifying seronegative personnel was 96%. Five seroconversions were identified during an average follow-up period of 15 to 17 months per person among 65 pediatric nurses whose CMV CF titers had initially been less than 1:8. No seroconversions were seen during an average follow-up period of 29 months per person among 27 hospitad little patient contact. The rate of acquisition of CMV infections in seronegative pediatric nurses was 4.1 to 7.7% per year. Sera from 9 of the 172 employees studied (5.2%) gave inconsistent results at the lower limits of the CF test.
Selective medium for growth of Proteus
Authors: Xilinas M E , Papavassiliou J T , Legakis N J
Published: June 2021

A medium containing heart infusion agar supplemented with bile salts, lithium chloride, sodium thiosulfate, and sodium citrate was developed for the selective growth of Proteus.
Nationwide epidemic of septicemia caused by contaminated intravenous products: mechanisms of intrinsic contamination
Authors: Mackel D C , Maki D G , Anderson R L , Rhame F S , Bennett J V
Published: June 2021

Between 1 July 1970 and April 1971, in many hospitals in this country, there were outbreaks of nosocomial septicemia caused by Enterobacter cloacae of E. agglomerans (formerly Erwinia, herbicola-lathyri). All of these hospitals used infusion products manufactured by one company, Abbott Laboratories, and all affected patients had onset of septicemia while receiving the company's infusion products. Septicemia was epidemiologically and microbiologically traced to intrinsic contamination of the company's screw-cap closure for infusion bottles which was sealed with a newly introduced elastomer liner. Epidemic organisms were isolated from these closures. Investigations both in the laboratory and in the manufacturing plant into the mechanism of contamination of these products revealed the following. (i) Epidemic strains were present in numerous areas throughout the manufacturing plants. (ii) Viable microorganisms gained access to the interior of screw-cap closures after the autoclave step of production. (iii) Cooling closures actively drew moisture through the thread interstices into the inner-most depths of the closure. (iv) Transfer of contaminants from closures to fluid was easily effected by simple manipulations duplicating normal in-hospital use. (v) The red-rubber liner used in the company's screw-cap closures before the introduction of elastomer contained a broad-spectrum antimicrobial inhibitor. The findings from this epidemic and the associated studies show that the screw-cap closure as it is now designed cannot be considered secure for products that must remain sterile.
Improved transport system for Neisseria gonorrhoeae in clinical specimens
Authors: Symington D A
Published: June 2021

Protective transport media have to be used to preserve Neisseria gonorrhoeae in clinical specimens during their transit to the laboratory. In this study, a CO2- environment chamber, the Jembec chamber, was used for transport of clinical speciments requiring examination for gonococci. The survival of N. gonorrhoeae present in clinical speciments when placed in Amies charcoal transport medium was compared to their survival when inoculated into Jembec chambers containing either modified Thayer-Martin medium (MTM) or modified New York City transport medium (MNYC). For a period of up to 2 days in transit, the three systems were not significantly different. However, after 3 days in transit, MNYC/Jembec chambers preserved significantly more gonococci than Amies charcoal transport meduim (P less than 0.0001) or MTM/Jembec chambers (P=0.006). MNYC/Jembec chambers withstood 241 miles (386 km) of postal transit during winter months; 80% of the gonococci present in clinical specimens remained viable from 2 to 5 days under these conditions. The CO2 generated by the tablet in the Jembec chamber was suggicient to support the growth of N. gonorrhoeae if the chambers were incubated at 36 C immediately after inoculation. However, if delayed in transit, the chambers had to be incubated in 5 to 10% CO2 to promote the growth of N. gonorrhoeae. MNYC/Jembec chambers provide a selective environment that will protect and maintain the viability of N. gonorrhoeae for extended periods, allowing a reasonable time for postal transit of clinical specimens to the laboratory.
Influence of the collection and transport of specimens on the recovery of bacteria from peritonsillar abscesses
Authors: Hallander H O , Flodström A , Holmberg K
Published: June 2021

In 30 patients with peritonsillar abscesses, pus was obtained by aspiration and by taking a swab after incision; bacterial recovery was compared. Although processed in the laboratory within 2 h, swab speciments gave results comparable to syringe specimens in only 9 of 13 patients with beta-hemolytic streptococci and 7 of 25 patients with anaerobic bacteria. Both kinds of microorganisms were lost in some cases but appeared as additional flora in others. The poor results from the swab technique was ascribed to overgrowth of respiratory flora contaminating the sample after incision. In aspirated pus kept in the syringe, or transferred to anaerobic transporters, the microbial flora was unchanged for 24 to 48 h. Some anaerobes also survived on agar slants for 24 h, but specially designed anaerobic transporters are recommended.
Experiments on terminal disinfection by formaldehyde vapor in the case of smallpox
Authors: Grossgebauer K , Spicher G , Peters J , Kuwert E , Pohle H D , Kerner H
Published: June 2021

The usually recommended terminal disinfection by formaldehyde vapor is unable to completely inactivate vaccinia viruses embedded in scabs. In view of our results, we recommend doubling the concentration of formaldehyde (10 g of formaldehyde per m3 of space) and prolonging the time of exposure to 24 h for terminal disinfection in the case of smallpox. Subsequent disinfection by scrubbing assumes special importance, since no complete inactivation of the scabs occurs.
Isolation of streptococcal nuclease B by batch adsorption
Authors: Slechta T F , Gray E D
Published: June 2021

A method has been developed for the preparation of streptococcal nuclease B by batch adsorpton to diethylaminoethyl-cellulose. The enzyme is homogeneous with respect to nuclease activity and is suitable for use as an antigen in measurement of anti-deoxyribonuclease B levels in sera.
Application of the single radial diffusion test for assay of antibody to influenza type A viruses
Authors: Mostow S R , Schild G C , Dowdle W R , Wood R J
Published: June 2021

Single radial diffusion (SRD) tests for antibodies to influenza type A hemagglutinin, neuraminidase, nucleoprotein, and matrix protein antigens were compared with conventional hemagglutination inhibition, neuraminidase inhibition, and complement fixation tests. Sera used in this study were obtained in 1968-1969 from volunteers before and after vaccination and before and after an ensuing epidemic of Hong Kong influenza. The SRD test compared favorably with conventional tests for assessment of vaccine- or infection-induced rises in antibody titers to influenza type A viruses. Little linear relationshiip was seen between zone areas with SRD and titers with conventional tests, suggesting that the SRD test may detect antibody of different quality or specificity. The SRD seemed equal to the hemagglutination inhibition test for predicting susceptibility to influenza. SRD is a simple test for the recognition of antibody to various antigenic components of the influenza virus and could prove to be a valuable epidemiological tool.
Polypectate digestion by Yersinia
Authors: von Riesen V L
Published: June 2021

The ability of Yersinia to digest polypectate may be of some value in differentiating Y. enterocolitica and Y. pseudotuberculosis from some of the other fermenting gram-negative bacilli, such as Enterobacter agglomerans, with which they can be confused. Pectolytic activity in Yersinia may also have some teleologic or taxonomic significance about which we do not care to speculate.
Isolation of
Vibrio alginolyticus
from Wound Infections
Authors: Rubin Sally Jo , Tilton Richard C.
Published: June 2021

Vibrio alginolyticus
was isolated from two patients with leg wounds. Both had a history of recent exposure to ocean water.
Clinical Isolation of
Yersinia enterocolitica
: Cold Temperature Enrichment
Authors: Greenwood J. R. , Flanigan S. M. , Pickett M. J. , Martin W. J.
Published: June 2021

A cold-temperature enrichment procedure was used to isolate
Yersinia enterocolitica
serotype 6 from a clinical stool specimen. The use of conventional laboratory media and enrichment procedures failed to isolate this organism.
Sequencing of Coastal Lagoon Samples from the Piñones Lagoon, Puerto Rico, Reveals Important Role of Bacterial Sulfur Metabolism in the Lagoon Ecosystem
Authors: Aviles Fabiola A. , Kyndt John A.
Published: June 2021

This initial microbial analysis of the Piñones lagoon shows a high representation of sulfur-oxidizing
Sulfurimonas
and sulfur-reducing
Sulfurospirillum
bacteria. These species are likely responsible for maintaining sulfur homeostasis and prevent the buildup of toxic sulfur components, but may contribute to nitrogen buildup, in the mangrove ecosystem.
Impact-induced hydrothermal dissolution in pyroxene: Petrographic and geochemical characterization of basalt-dominated polymict impact breccias from the Vargeão Dome, Brazil
Authors: Epstein Jennifer , Pittarello* Lidia , Crósta Álvaro P. , Koeberl Christian
Published: June 2021

Constraints on impact-related hydrothermal alteration are important to enable the reconstruction of the possible processes affecting the surface of other terrestrial planets, such as Mars. Terrestrial impact structures excavated in basaltic targets provide the opportunity for analog studies. In Brazil, seven impact structures have been confirmed so far. Three of them, Vargeão Dome, Vista Alegre, and Cerro do Jarau, were formed in the same basaltic province belonging to the Paraná Basin, and they have several common characteristics. Oxidized basaltic breccias locally containing sandstone clasts occur in all these structures. In this work, selected samples of such breccias from the Vargeão Dome impact structure in southern Brazil were petrographically and geochemically investigated to further constrain the effects of the postimpact hydrothermal alteration. The breccia matrix shows typical oxidation effects induced by postimpact hydrothermal fluids, which highlight its heterogeneous nature, related to the impact event, and mixing components from different pre-impact stratigraphic formations. The detection of partially dissolved exsolution lamellae in pyroxene and of related alteration products constrains the effects of hydrothermal alteration in the basalts of the Vargeão Dome, which could serve as a terrestrial analog for planetary studies.
Aberrant sphingomyelin31P-NMR signatures in giant cell tumour of bone
Authors: Quiroz-Acosta Tayde , Flores-Martinez Yazmin Montserrat , Becerra-Martínez Elvia , Pérez-Hernández Elizabeth , Pérez-Hernández Nury , Bañuelos-Hernández Angel Ernesto
Published: June 2021

An understanding of the biochemistry of the giant cell tumour of bone (GCTB) provides an opportunity for the development of prognostic markers and identification of therapeutic targets. Based on metabolomic analysis, we proposed glycerophospholipid metabolism as the altered pathway in GCTB., The objective of this study was to identify these altered metabolites. Using phosphorus-31 nuclear magnetic resonance spectroscopy (31P-NMR), sphingomyelin was determined to be the most dysregulated phospholipid in tissue samples from six patients with GCTB. Enzymes related to its biosynthesis and hydrolysis were examined using immunodetection techniques. High expression of sphingomyelin synthases 1 and 2, but low expression of neutral sphingomyelinase 2 (nSMase2) was found in GCTB tissues compared to non-neoplastic bone tissues. Sphingomyelin/ceramide biosynthesis is dysregulated in GCTB due to alterations in the expression of SMS1, SMS2, and nSMase2.
Considerations for measuring residual stresses in driven piles with vibrating wire strain gauges
Authors: Bartz James R. , Blatz James A.
Published: June 2021

Vibrating wire strain gauges are often the preferred technology for measuring strain in driven piles. However, measuring the residual strain after pile driving is challenging to accomplish using vibrating wire gauges. The driving process can cause a shift in the no-load reading from a relaxation of locked-in manufacturing strains in the pile or relaxation of the gauge wire tension. Also, there are temperature effects from installing piles below ground. A test pile program was developed using driven steel H-piles instrumented with vibrating wire strain gauges. The piles were subjected to dynamic forces by striking against a steel plate in an attempt to relax the locked-in manufacturing strain prior to installation. The strain gauges and thermistors were connected to a data logger during pile driving to record strain and temperature changes following installation. It was observed that applying a dynamic impact to the piles prior to installation resulted in a shift of 0–5 με (microstrain). Temperature effects from installing the piles in cooler ground resulted in a shift of strain in excess of 60 με in some strain gauges. It is concluded that temperature-induced shifts to strain must be measured following pile driving to interpret residual stresses.
Comparative analyses with conventional surveys reveal the potential for an angler app to contribute to recreational fisheries monitoring
Authors: Johnston Fiona D. , Simmons Sean , Poorten Brett van , Venturelli Paul
Published: June 2021

Growing interest in apps to collect recreational-fisheries data requires that relationships between self-reported data and other fisheries data are evaluated, and that potential biases are assessed. This study compared results from a mobile-phone application and website for anglers (MyCatch) to results from three types of fisheries surveys — 1 provincial-level mail survey, 2 creel, and 17 gillnet surveys. Results suggest that an app and website can (i) recruit users that have a broad spatial distribution that is similar to conventional surveys, (ii) generate data that capture regional fishing patterns (2218 trips on 289 lakes and 90 streams or rivers), and (iii) provide catch rate estimates that are similar to those from other fisheries-dependent surveys. Some potential biases in app users (e.g., urban bias) and in the relative composition of species caught provincially were identified. The app was not a suitable tool for estimating fish abundance and relative community composition. Our study demonstrates how apps can or cannot provide a complementary data-collection tool for recreational-fisheries monitoring, but further research is needed to determine the applicability of our findings to other fisheries contexts.
Curing the unphysical behaviour of NLO quarkonium production at the LHC and its relevance to constrain the gluon PDF at low scales
Authors: Lansberg Jean-Philippe , Ozcelik Melih A.
Published: June 2021

We address the unphysical energy dependence of quarkonium-hadroproduction cross sections at Next-to-Leading Order (NLO) in $$\alpha _s$$

α
s

which we attribute to an over-subtraction in the factorisation of the collinear singularities inside the PDFs in the $$\overline{\text {MS}}$$

MS
¯

scheme. Such over- or under-subtractions have a limited phenomenological relevance in most of the scattering processes in particle physics. On the contrary, it is particularly harmful for $$P_T$$

P
T

-integrated charmonium hadroproduction which renders a wide class of NLO results essentially unusable. Indeed, in such processes, $$\alpha _s$$

α
s

is not so small, the PDFs are not evolved much and can be rather flat for the corresponding momentum fractions and, finally, some process-dependent NLO pieces are either too small or too large. We propose a scale-fixing criterion which avoids such an over-subtraction. We demonstrate its efficiency for $$\eta _{c,b}$$

η

c
,
b

but also for a fictitious light elementary scalar boson. Having provided stable NLO predictions for $$\eta _{c,b}$$

η

c
,
b

$$P_T$$

P
T

-integrated cross sections, $$\sigma ^{\mathrm{NLO}}_{\eta _Q}$$

σ

η
Q

NLO

, and discussed the options to study $$\eta _{b}$$

η
b

hadroproduction, we argue that their measurement at the LHC can help better determine the gluon PDF at low scales and tell whether the local minimum in conventional NLO gluon PDFs around $$x=0.001$$

x
=
0.001

at scales below 2 GeV is physical or not.
Emulating complex networks with a single delay differential equation
Authors: Stelzer Florian , Yanchuk Serhiy
Published: June 2021

A single dynamical system with time-delayed feedback can emulate networks. This property of delay systems made them extremely useful tools for Machine-Learning applications. Here, we describe several possible setups, which allow emulating multilayer (deep) feed-forward networks as well as recurrent networks of coupled discrete maps with arbitrary adjacency matrix by a single system with delayed feedback. While the network’s size can be arbitrary, the generating delay system can have a low number of variables, including a scalar case.
THE 2008 ECONOMIC STIMULUS PLAN AND HOUSING PRICE: THE ROLE OF SOES
Authors: HAN SHI-ZHUAN , WEI HONGHONG , HUANG BIHONG , LI JIE
Published: June 2021

How does China’s 2008 economic stimulus plan affect housing price through the channel of state-owned enterprises (SOEs)? Utilizing a sample of 206 Chinese cities and a different-in-difference approach, we show that the housing prices in cities with a higher prevalence of SOEs, tend to grow disproportionately faster than that in cities with lower prevalence of SOEs after the shock of 2008 China’s stimulus plan. The heterogeneity tests show that the SOE channel plays a more important role in cities with more city investment bonds, less financial development and lower level of marketization. Our conclusion is robust across a battery of sensitivity tests.
F-theory models with 3 to 8 U(1) factors on K3 surfaces
Authors: Kimura Yusuke
Published: June 2021

In this study, we construct four-dimensional F-theory models with 3 to 8 U(1) factors on products of K3 surfaces. We provide explicit Weierstrass equations of elliptic K3 surfaces with Mordell–Weil ranks of 3 to 8. We utilize the method of quadratic base change to glue pairs of rational elliptic surfaces together to yield the aforementioned types of K3 surfaces. The moduli of elliptic K3 surfaces constructed in the study include Kummer surfaces of specific complex structures. We show that the tadpole cancels in F-theory compactifications with flux when these Kummer surfaces are paired with appropriately selected attractive K3 surfaces. We determine the matter spectra on F-theory on the pairs.
The impurity states in InGaAsP/InP coaxial double quantum well wires with the effects of electric and magnetic fields
Authors: Hu Min , Wang Hailong , Gong Qian
Published: June 2021

The hydrogen donor impurity states are calculated in [Formula: see text] coaxial double quantum well wires by the plane wave method under the theoretical framework of effective mass envelope function approximation. The binding energies of impurity in [Formula: see text] state and [Formula: see text] state are obtained as the functions of impurity position, distance between the inner and outer quantum wires, magnetic and electric field strengths. Transition energies are calculated as the functions of impurity position, distance between the inner and outer quantum wires. The effects of quantum wire thickness and distance of quantum wires on impurity states are analyzed in detail. It is found that the effects of electric field and magnetic field on binding energy of [Formula: see text] state are different for impurity located at different positions.
Electronic property of intrinsic point defect system on β–Si3N4(0001) surface
Authors: Li Lingxia , Lu Xuefeng , Luo Jianhua , Guo Xin , Ren Junqiang , Xue Hongtao , Tang Fuling
Published: June 2021

The intrinsic point defect influence data for [Formula: see text]–Si3N4by far are incomplete and experimental clarification is not easy. In this contribution, the effects of vacancy ([Formula: see text], [Formula: see text] and [Formula: see text]) and interstitial ([Formula: see text] and [Formula: see text]) defects on the electronic properties of H-passivated [Formula: see text]–Si3N4(0001) surface are explored based on density functional theory (DFT) calculation. The results show that it is easier to form [Formula: see text] vacancy defects in the surface layer under Si-rich conditions. The existence of N vacancies makes the bottom of conduction bands shift downwards, and the top of valance band is away from Fermi level. The presence of [Formula: see text] makes the system have the characteristics of p-type semiconductor, and the closer to the inner layer, the narrower the range of additional energy bands and the greater the degree of localization of electrons. The closer the Si atom vacancy is to the surface, the smaller the photon energy corresponding to the maximum absorption coefficient is. Compared with the N vacancy system, the Si vacancy system has higher reflection ability in the low energy region. For the interstitial defect systems, [Formula: see text] is easy to form on the surface layer, and [Formula: see text] is easy to produce in the inner layer. The [Formula: see text] system has a new additional energy level at the Fermi level, and as the [Formula: see text] is closer to the inner layer, the energy range of the additional energy level is also narrower. In the [Formula: see text] system, the new additional energy levels appear at the Fermi level and the intermediate band. The results have positive significance for the design of this advanced structural and functional integrated ceramics. The absorption coefficient and reflection coefficient of [Formula: see text] system are much higher than those of other systems when the energy is greater than 2.5 eV.
Euler Transformation of Polyhedral Complexes
Authors: Gupta Prashant , Krishnamoorthy Bala
Published: June 2021

We propose an Euler transformation that transforms a given [Formula: see text]-dimensional cell complex [Formula: see text] for [Formula: see text] into a new [Formula: see text]-complex [Formula: see text] in which every vertex is part of the same even number of edges. Hence every vertex in the graph [Formula: see text] that is the [Formula: see text]-skeleton of [Formula: see text] has an even degree, which makes [Formula: see text] Eulerian, i.e., it is guaranteed to contain an Eulerian tour. Meshes whose edges admit Eulerian tours are crucial in coverage problems arising in several applications including 3D printing and robotics.

For [Formula: see text]-complexes in [Formula: see text] ([Formula: see text]) under mild assumptions (that no two adjacent edges of a [Formula: see text]-cell in [Formula: see text] are boundary edges), we show that the Euler transformed [Formula: see text]-complex [Formula: see text] has a geometric realization in [Formula: see text], and that each vertex in its [Formula: see text]-skeleton has degree [Formula: see text]. We bound the numbers of vertices, edges, and [Formula: see text]-cells in [Formula: see text] as small scalar multiples of the corresponding numbers in [Formula: see text].

We prove corresponding results for [Formula: see text]-complexes in [Formula: see text] under an additional assumption that the degree of a vertex in each [Formula: see text]-cell containing it is [Formula: see text]. In this setting, every vertex in [Formula: see text] is shown to have a degree of [Formula: see text].

We also present bounds on parameters measuring geometric quality (aspect ratios, minimum edge length, and maximum angle of cells) of [Formula: see text] in terms of the corresponding parameters of [Formula: see text] for [Formula: see text]. Finally, we illustrate a direct application of the proposed Euler transformation in additive manufacturing.
A systematic analysis of transverse momentum spectra of J/ψ mesons in high energy collisions
Authors: Zhang Xu-Hong , Liu Fu-Hu , Olimov Khusniddin K.
Published: June 2021

We aggregate the transverse momentum spectra of [Formula: see text] mesons produced in high energy gold–gold (Au–Au), deuteron–gold ([Formula: see text]Au), lead–lead (Pb–Pb), proton–lead ([Formula: see text]–Pb), and proton–(anti)proton ([Formula: see text]–[Formula: see text]) collisions measured by several collaborations at the Relativistic Heavy Ion collider (RHIC), the Tevatron Proton–Antiproton Collider, and the Large Hadron Collider (LHC). The collision energy (the center-of-mass energy) gets involved in a large range from dozens of GeV to 13 TeV (the top LHC energy). We consider two participant or contributor partons, a charm quark and an anti-charm quark, in the production of [Formula: see text]. The probability density of each quark is described by means of the modified Tsallis–Pareto-type function (the TP-like function) while considering that both quarks make suitable contributions to the [Formula: see text] transverse momentum spectrum. Therefore, the convolution of two TP-like functions is applied to represent the [Formula: see text] spectrum. We adopt the mentioned convolution function to fit the experimental data and find out the trends of the power exponent, effective temperature, and of the revised index with changing the centrality, rapidity, and collision energy. Beyond that, we capture the characteristic of [Formula: see text] spectrum, which is of great significance to better understand the production mechanism of [Formula: see text] in high energy collisions.
Morphology Preserving Segmentation Method for Occluded Cell Nuclei from Medical Microscopy Image
Authors: Khan Rafflesia , Debnath Rameswar
Published: June 2021

Nowadays, image segmentation techniques are being used in many medical applications such as tissue culture monitoring, cell counting, automatic measurement of organs, etc., for assisting doctors. However, high-level segmentation results cannot be obtained without manual annotation or prior knowledge for high variability, noise and other imaging artifacts in medical images. Furthermore, unstable and continuously changing characteristics of all human cells, tissues and organs manipulate training-based segmentation methods. Detecting appropriate contour of a region of interest and single cells from overlapping condition are extremely challenging. In this paper, we aim for a model that can detect biological structure (e.g. cell nuclei and lung contour) with their proper morphology even in overlapping or occluded condition without manual annotation or prior knowledge. We have introduced a new optimal approach for automatic medical image region segmentation. The method first clearly focuses the boundaries of all object regions in a microscopy image. Then it detects the areas by following their contours. Our model is capable of detecting and segmenting object regions from medial image using less computation effort. Our experimental results prove that our model provides better detection on several datasets of different types of medical data and ensures more than 98% segmentation rate in the case of densely connected regions.
Optimal Scheduling of Flow Shop Based on Genetic Algorithm
Authors: Wang Zhenqi
Published: June 2021

With the rapid development of the social economy, the requirements for the production efficiency of job shop have also increased, but the production efficiency of the traditional flow shop is no longer suitable for the efficient speed of economic development. Therefore, it is an urgent task to study the problem of optimal scheduling of flow shop. In this study, the problem of optimal scheduling of the flow shop was taken as the main research subject, the machining sequence and maximum completion time were taken as the key points, a method of optimal scheduling by genetic algorithm (GA) was proposed, and a mathematical model for optimal scheduling of the flow shop based on GA was established. The optimal processing sequence of the six jobs in the production was obtained: 2–1–6–5–4–3; the average completion time was 381.6[Formula: see text]min, and the optimal solution frequency was 0.8. Moreover, the total processing time of the GA-based flow shop was shorter than that of the traditional flow shop. This work provides a new route for the optimal scheduling of flow shop.
Dynamics of quasi-de Sitter and linear combination of exponential models in extended gravity
Authors: Mishra B. , Gadia Eesha , Tripathy S. K.
Published: June 2021

In this paper, we have studied the dynamical aspects of some cosmological models in an isotropic space-time within the framework of an extended gravity theory. Two accelerating cosmological models are presented with quasi-de Sitter (QDS) and linear combination of exponential (LCE) scale factors. The geometrical testing mechanism has been performed and analyzed. While the results of the QDS model show a departure from the concordant [Formula: see text]CDM model, the resulting behavior of the LCE model seems to be compatible with the [Formula: see text]CDM model only at the present epoch and is incompatible in the near past.