bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of Stirling driven desalination power system
Authors: Chen Rui
Published: January 2021

This paper presents a new power system for reverse osmosis desalination, which is composed of a Stirling engine driven booster pump and a reciprocating piston pump rigidly connected. Firstly, the physical model is established by SolidWorks, and then the frequency of reciprocating motion of piston is calculated through the principle of piston component motion. Then, the UDF file of piston motion is compiled. Then, CFD analysis is carried out by FLUENT software to select the standard the temperature field, velocity field and pressure field in the pump chamber of Stirling engine are simulated by coupled method, and the output work of the engine is studied. The results show that the gas movement in Stirling engine is stable, the pressure at the discharge port of reciprocating pump is greater than the required osmotic pressure, and the whole power system can operate normally.
Research on 2D Temperature Field Measurement Method of Mg/CO2 Combustion Flame Based on Color CCD
Authors: Hu Kun , Xu Yihua , Li Minjie , Gu Xiang
Published: January 2021

A new Mg/CO2 powder rocket propulsion system is proposed for Mars exploration. Accurate measurement of Mg/CO2 combustion flame temperature field has important reference value for understanding the combustion characteristics and operating conditions. In this paper, the two dimensional temperature field of the Mg/CO2 combustion flame is obtained by building a Mg/CO2 combustion device and colorimetric temperature measurement system based on the color charge coupled device (CCD). The influence of magnesium powder particle size, premixed Reynolds number, and CO2/Mg oxygen fuel ratio on the flame temperature of Mg/CO2 combustion are discussed. The results show that the maximum temperature of Mg/CO2 combustion flame under different working conditions is between 2500K and 2900K, and it increases with the increase of magnesium powder particle size, premixed Reynolds number, and oxygen-fuel ratio.
Study of a New Type of Electric Car: Solar-Powered Car
Authors: An Tongrui
Published: January 2021

This article shows the difference between solar-powered cars and pure electric cars, the advantages of using solar panels to provide electricity as well as the distance range increased by converting sunlight into electricity. I also discuss and give some reasons that solar-powered cars can be expected to become widespread in the future.
Hair Oppression and Appropriation
Authors: Chaves Andrea Mejía , Bacharach Sondra
Published: January 2021

In countries like the United States, White people benefit from appropriating Black hair culture, even while Black men and women experience race-based hair discrimination and oppression. One goal of this paper is to raise awareness of hair discrimination and oppression within the philosophical community. Another is to consider whether current theories of appropriation can account for the wrongness of this widespread phenomenon and, if so, how. We are particularly interested in the special case where one minority group appropriates from another minority group—viz. the appropriation of Black hairstyles by Non-Black Persons of Colour (NBPoC). Our paper highlights the complexity of appropriation claims between competing minority groups—both of which have been oppressed, albeit differently, by White people— due to their multi-ethnic, multicultural and, therefore, intersectional, status.
Invited Commentary: The Uneven Gender Revolution and the Gender Gap in Depression in the United States
Authors: Shafer Emily Fitzgibbons
Published: January 2021

Women suffer depression at higher rates than men. In a meta-analysis using data from 1982–2017, Platt et al. (Am J Epidemiol. 2021;000(00):000–000) examine trends by age group in the gender depression gap and find no change in the depression gap among adults despite large changes in women’s opportunities during the same time period. They do, however, find an increase over time in the gender gap in depression among adolescents. I concur with Platt et al. that likely explanations for their findings involve the social environment. For adult women, the burden of being responsible for the majority of the household labor and the rise in unmarried parenting are likely explanations for why increased paid work opportunities have not resulted in a decrease in the gender gap in depression. For adolescents, the increase might be due to the popularity of social media rising at the same time expectations surrounding beauty and attractiveness heightened for girls and young women. Platt et al. highlight the relationship between the uneven change of the “gender revolution” and depression.
Molecular and phenotypic variation of the white locus region in Drosophila melanogaster.
Authors: Miyashita N , Langley C H
Published: January 2021

Restriction site and insertion/deletion polymorphism in a 45-kb region of the white locus on the X chromosome in Drosophila melanogaster was investigated for 64 X chromosome lines with six 6-cutter and ten 4-cutter restriction enzymes. A total of 109 polymorphisms were detected (54 restriction sites and 55 insertions/deletions). Estimated heterozygosity per nucleotide for this region (0.004-0.008) was similar to those of the Adh and 87A heat-shock locus regions located on the autosomes in D. melanogaster. This is contrary to a simple prediction based on the theory of mutation selection-balance of partially recessive deleterious mutants which predicts less variation on X chromosomes. Large linkage disequilibria between pairs of polymorphisms (including insertions and deletions) within the transcriptional unit (especially the 3' end of the 1st intron) were observed. As expected from population genetics theory, linkage disequilibria between these polymorphisms were greater for those pairs that are physically closer on the restriction map. Linkage equilibrium was typically observed when the pairs of sites were separated by 2 kb or more. Although significant between-line variation in eye pigment was observed (P less than 0.05), there is little evidence for strong associations between this phenotype and the polymorphisms at the DNA level.
Evidence for frameshift mutations in the hisH gene of Escherichia coli causing synthesis of a partially active glutamine amidotransferase.
Authors: Pons F W , Neubert U , Müller P
Published: January 2021

Among eight strains carrying acridine-induced mutations in hisH, five which mapped at four different sites in the promoter-distal region of the gene showed His+ phenotypes on media containing a purine. By complementation analysis, hisH enzyme was shown to be required for growth on purines. Purine-sensitive His+ revertants of strains able to grow on purines carried second-site mutations which in one case could be shown to map in hisG. Strains able to grow on purines were able to grow on 2-thiazolyl-DL-alanine, too. We conclude that frameshift mutations in the promoter-distal part of the hisH gene of E. coli do not completely abolish the activity of the gene product.
Transformation of yeast by agitation with glass beads.
Authors: Costanzo M C , Fox T D
Published: January 2021

We have found that agitation of Saccharomyces cerevisiae with glass beads and plasmid DNA using a vortex mixer results in genetic transformation of the yeast cells. This method is less efficient, but considerably more convenient, than other yeast transformation procedures. The fact that the minimal requirements for transformation are simply physical damage and the presence of DNA in an osmotically supportive environment suggests that this process may occur in nature.
Identification of REO1, a gene involved in negative regulation of COX5b and ANB1 in aerobically grown Saccharomyces cerevisiae.
Authors: Trueblood C E , Poyton R O
Published: January 2021

In Saccharomyces cerevisiae, the COX5a and COX5b genes constitute a small gene family that encodes two forms of cytochrome c oxidase subunit V, Va and Vb, either of which can provide a function essential for cytochrome c oxidase activity and respiration. In aerobically grown wild-type yeast cells, Va is the predominant form of subunit V. The COX5b gene alone does not produce enough Vb to support a respiration rate sufficient to allow growth on nonfermentable carbon sources. By selecting for mutations that increase the respiratory capacity of a strain deleted for COX5a, we have identified a gene that is involved in negative regulation of COX5b expression under aerobic growth conditions. Each of four independently isolated reo1 mutations are shown to be recessive, unlinked to COX5b, but dependent on COX5b for phenotypic expression. The mutations define a single complementation and linkage group: designated as REO1 for regulator of expression of oxidase. reo1 mutations increase expression of COX5b in aerobically grown cells, but not in anaerobically grown cells, where expression is already elevated. These mutations have no effect on COX5a, the other member of this small gene family which is positively regulated by heme and oxygen. The REO1 gene does play a role in repression of ANB1, a gene that is normally repressed under aerobic but not anaerobic conditions. Neither rox1 or rox3 mutations, which have previously been shown to increase ANB1 expression, are in the same complementation group as reo1 mutations.
Sequence amplification and gene rearrangement in parasitic nematode mitochondrial DNA.
Authors: Hyman B C , Beck J L , Weiss K C
Published: January 2021

The nematode Romanomermis culicivorax, an obligate mosquito parasite, possesses a 26 kilobase (kb) mitochondrial genome. The unusually large size is due to transcriptionally active DNA sequences present as 3.0 kb direct tandem repeats and as inverted portions of the repeating unit located elsewhere in the mitochondrial DNA (mtDNA). The genome rearrangements involved in establishing this unusual sequence organization may have dramatically altered conventional mitochondrial gene order. Genes for subunits of the cytochrome c oxidase complex (COI and COII) are normally closely linked in animal mtDNAs, but are separated by approximately 8 kb in this mitochondrial genome.
Design and analysis of experiments on random drift and inbreeding depression.
Authors: Lynch M
Published: January 2021

While the genetic consequences of inbreeding and small population size are of fundamental importance in many areas of biology, empirical research on these phenomena has proceeded in the absence of a well-developed statistical methodology. The usual approach is to compare observed means and variances with the expectations of Wright's neutral, additive genetic model for quantitative characters. If the observations deviate from the expectations more than can be accounted for by sampling variance of the parameter estimates, the null hypothesis is routinely rejected in favor of alternatives invoking evolutionary forces such as selection or nonadditive gene action. This is a biased procedure because it treats sequential samples from the same populations as independent, and because it ignores the fact that the expectations of the neutral additive genetic model will rarely be realized when only a finite number of lines are studied. Even when genes are perfectly additive and neutral, the variation among the properties of founder populations, the random development of linkage disequilibrium within lines, and the variance in inbreeding between lines reduce the likelihood that Wright's expectations will be realized in any particular set of lines. Under most experimental designs, these sources of variation are much too large to be ignored. Formulas are presented for the variance-covariance structure of the realized within- and between-line variance under the neutral additive genetic model. These results are then used to develop statistical tests for detecting the operation of selection and/or inbreeding depression in small populations. A number of recommendations are made for the optimal design of experiments on drift and inbreeding, and a method is suggested for the correction of data for general environmental effects. In general, it appears that we can best understand the response of populations to inbreeding and finite population size by studying a very large number (>100) of self-fertilizing or full-sib mated lines in parallel with one or more stable control populations.
A genetic analysis of suppressors of the PF10 mutation in Chlamydomonas reinhardtii.
Authors: Dutcher S K , Gibbons W , Inwood W B
Published: January 2021

A mutation at the PF10 locus of the unicellular green alga Chlamydomonas reinhardtii leads to abnormal cell motility. The asymmetric form of the ciliary beat stroke characteristic of wild-type flagella is modified by this mutation to a nearly symmetric beat. We report here that this abnormal motility is a conditional phenotype that depends on light intensity. In the absence of light or under low light intensities, the motility is more severely impaired than at higher light intensities. By UV mutagenesis we obtained 11 intragenic and 70 extragenic strains that show reversion of the pf10 motility phenotype observed in low light. The intragenic events reverted the motility phenotype of the pf10 mutation completely. The extragenic events define at least seven suppressor loci; these map to linkage groups IV, VII, IX, XI, XII and XVII. Suppressor mutations at two of the seven loci (LIS1 and LIS2) require light for their suppressor activity. Forty-eight of the 70 extragenic suppressors were examined in heterozygous diploid cells; 47 of these mutants were recessive to the wild-type allele and one mutant (bop5-1) was dominant to the wild-type allele. Complementation analysis of the 47 recessive mutants showed unusual patterns. Most mutants within a recombinationally defined group failed to complement one another, although there were pairs that showed intra-allelic complementation. Additionally, some of the mutants at each recombinationally defined locus failed to complement mutants at other loci. They define dominant enhancers of one another.
INTRAGENIC DELETIONS AND SALIVARY BAND RELATIONSHIPS IN DROSOPHILA
Authors: Welshons W J , Keppy D O
Published: January 2021

In the absence of assumptions pertaining to the organization and function of chromomeric DNA, the cytogenetic analysis of intragenic deletions that start at Notch and spread to the right or left of the locus suggests that the recombinational gene is bilaterally associated with salivary band 3C7. Either there are two genes resolved as a single cistron, or one must seek an alternative interpretation that allows some modicum of independent in the relationship between gene and band. Although we momentarily lean toward the hypothesis that gene and salivary band are separate entities on a binemic chromosome, alternative views can be devised, and the data must remain open to reinterpretation.—The recessive visible allele faswb behaves as a point mutant at the left end of the map and seems to be a deletion in the interval 3C6 to 7; we suspect some part of the band is missing. We have used the aberration in faswb as a cytological marker, isolated intragenic recombinants, and subjected them to examination. The analysis indicates that the chromosomal interchanges occurred to the right of 3C7.
REQUIREMENT FOR CELL DISPERSION PRIOR TO SELECTION OF INDUCED AZAGUANINE-RESISTANT COLONIES OF CHINESE HAMSTER CELLS
Authors: Myhr B C , DiPaolo J A
Published: January 2021

With V79 Chinese hamster cell cultures treated with a mutagen, the maximum frequency of colonies resistant to 8-azaguanine (AZG) was attained when the cells were dispersed after a suitable expression time before adding the selection medium. V79–4 cells were exposed to 500 µM MMS, 7 µM AFAA, or 10 µM MNNG and allowed to multiply before being reseeded at 4 × 104 cells/60 mm dish and selected with 10 µg/ml AZG. Maximum frequencies of 4 × 10-5, 4 × 10-4, and 2.4 × 10-3 were obtained about 100, 130, and 200 hrs after exposure to MMS, AFAA, and MNNG, respectively. The maximum frequencies following MMS or MNNG treatments were about 10-fold greater than those obtained when induction and selection of AZG-resistant colonies were performed in the same culture dish. The reseeding of treated cells eliminated the possibility of metabolic cooperation within mosaic colonies of wild-type and mutant cells and achieved expression of the induced changes before intercolony crossfeeding reduced the frequency of resistant colonies.—AZG-resistant colonies were selected in medium containing dialyzed fetal bovine serum, and the selection medium was replaced at least twice. Both serum dialysis and selection medium replacement were necessary for consistent achievement of background frequencies of resistant colonies near 10-6. Reconstruction experiments with AZG-resistant V79 lines showed that the efficiency of recovery of resistant cells in the selection medium was constant over a range of 0–20 colonies observed/dish. A mixed population of V79 and AZG-resistant cells was also correctly analyzed by the procedure used in mutagenesis studies.
PRIMARY HOMOTHALLISM—RELATION TO HETEROTHALLISM IN THE REGULATION OF SEXUAL MORPHOGENESIS IN SISTOTREMA
Authors: Ullrich Robert C , Raper John R
Published: January 2021

The wood-rotting basidiomycete, Sistotrema brinkmannii, is an aggregate of biological species possessing several variations—homothallism, bipolar heterothallism and tetrapolar heterothallism—on the genetic regulation of a critical phase of development. Nutritionally forced intra- and interspecific matings provide genetic information about the relatedness of homothallic isolates, the relation of the various species to one another, the genetic basis of homothallism, and its relationship to heterothallism. Most homothallic isolates are interfertile when nutritionally forced. Successful hybridization between species is restricted to particular combinations of homothallic × bipolar isolates. Significant findings of these studies include: (1) documentation of hybridization of biological species in the Homobasidiomycetes, (2) documentation of the relatedness of two naturally occurring, variant systems, homothallism and bipolar heterothallism, that regulate sexual morphogenesis in the higher fungi, (3) evidence for definite, but limited, evolutionary divergence of the polygenic, regulated components of the respective systems, and (4) indication that the genetic basis of homothallism in this system is essentially due to constitutive function and consequently is fundamentally different from presently understood mechanisms in other self-fertile systems.
THE EVOLUTION OF SELECTIVELY SIMILAR ELECTRO-PHORETICALLY DETECTABLE ALLELES IN FINITE NATURAL POPULATIONS
Authors: Wehrhahn C F
Published: January 2021

Most of the models of population genetics are not realistic when applied to data on electrophoretic variants of proteins because the same net charge may result from any of several amino acid combinations. In the absence of realistic models they have, however, been widely used to test competing hypotheses about the origin and maintenance of genetic variation in populations. In this paper I present a general method for determining probability generating functions for electrophoretic state differences. Then I use the method to find allelic state difference distributions for selectively similar electrophoretically detectable alleles in finite natural populations.

Predicted patterns of genetic variation, both within and among species, are in reasonable accord with those found in the Drosophila willistoni group by Ayala et al. (1972) and by Ayala and Tracey (1974).
GENETIC ANALYSIS OF COPPER RESISTANCE IN PARAMECIUM AURELIA SYNGEN 4
Authors: Nyberg Dennis
Published: January 2021

Measurement of the median tolerance limit to cupric ion of 28 wild stocks of Paramecium aurelia syngen 4 revealed a phenotypic polymorphism; two stocks showed a much greater resistance than the others. Genetic analysis showed the resistant phenotype was produced by a recessive allele, cur, identical in both resistant wild stocks. No modification of the phenotypic expression of this allele could be detected after backcrossing into different genetic backgrounds. The results are interpreted to support the importance of mutational adaptation in this inbreeding species. Possible patterns of internal genetic organization of species which rely on mutation for adaptation are discussed.
TEMPERATURE-SENSITIVE MUTANTS OF A CHINESE HAMSTER CELL LINE. I. SELECTION OF CLONES WITH DEFECTIVE MACROMOLECULAR BIOSYNTHESIS
Authors: Roufa Donald J , Reed Susan J
Published: January 2021

Temperature-sensitive clones have been selected from a mutagenized culture of Chinese hamster lung cells by a procedure involving bromodeoxy-uridine (BrdU) incorporation and irradiation with black light. The selection procedure used in these studies was adapted from methods developed by others to yield mutants that cease DNA replication within a short time after they are transferred to nonpermissive temperature. After mutagenesis with ethyl methanosulfonate ten clones survived the selection procedure. Three of the clones (mutants) were temperature-sensitive as measured by growth properties. Two mutants ceased DNA synthesis within six hours of being shifted to 39° and the third mutant continued to synthesize DNA at nonpermissive temperature at a reduced rate for at least 24 hours. Thus, all three mutants survived the selection procedure for understandable reasons, since each was unable to incorporate sufficient BrdU at 39° to lethally protosensitize its DNA during the standard exposure period. The two mutants that cease DNA synthesis at high temperature (clones 115-47 and 115-53) also stop incorporating radioactive amino acids and uridine within six hours at 39°. Their complex phenotype, i.e. defective DNA, RNA and protein biosynthesis, is reversible. When these mutants were returned to 33° after 8 hours at 39°, both resumed DNA synthesis immediately (< 1 hour). Reversal of defective DNA synthesis in both mutants was sensitive to drugs that inhibit protein biosynthesis specifically. Those same drugs, as well as toxic amino acids analogs, also effected a striking mutant phenocopy in wild-type cells. The phenocopy produced by amino acid analogs that are incorporated into mammalian proteins suggested that one or more proteins must be synthesized continuously to support mammalian cells engaged in programmed DNA replication.
LIMITS TO THE ADVANTAGE OF RECOMBINATION IN INCREASING THE RATE OF INCORPORATION OF FAVORABLE MUTANTS
Authors: Nyberg Dennis
Published: January 2021

The advantage of recombination in increasing the rate of incorporation of favorable mutants is shown to disappear for large NU if substitution is occurring at only two loci. Recombination will, on the average, destroy all double favorable individuals in a haploid population until the product of the frequencies of the single favorable mutants exceeds 1/N. As NU increases there is an increasing probability of the occurrence of the double favorable my mutation alone. Recombination provides a significant advantage in the rate of incorporation of favorable mutants only if 2 s/lnN<NU<2c when substitution is occurring at only two loci. If substitution is occurring at more than two loci the recombining population apparently has a substantial advantage for large NU.
Should we be measuring DNA damage in human spermatozoa? New light on an old question
Authors: Aitken R John , Bakos Hassan W
Published: January 2021

Assessments of sperm DNA damage are controversial because of perceived uncertainties over the relationship with pregnancy and the limited range of therapies available should positive results be returned. In this article, we highlight recent data supporting a chain of associations between oxidative stress in the male germ line, DNA damage in spermatozoa, defective DNA repair in the oocyte, the mutational load carried by the resulting embryo and the long-term health trajectory of the offspring. Any condition capable of generating oxidative damage in spermatozoa (age, obesity, smoking, prolonged abstinence, varicocele, chemical exposures, radiation etc.) is capable of influencing offspring health in this manner, creating a range of pathologies in the progeny including neuropsychiatric disorders and cancer. If sperm DNA damage is detected, there are several therapeutic interventions that can be introduced to improve DNA quality prior to the use of these cells in ART. We therefore argue that infertility specialists should be engaged in the diagnosis and remediation of sperm DNA damage as a matter of best practice, in order to minimize the risk of adverse health outcomes in children conceived using ART.
Rivers of gas – I. Unveiling the properties of high redshift filaments
Authors: Ramsøy Marius , Slyz Adrianne , Devriendt Julien , Laigle Clotilde , Dubois Yohan
Published: January 2021

At high redshift, the cosmic web is widely expected to have a significant impact on the morphologies, dynamics, and star formation rates of the galaxies embedded within it, underscoring the need for a comprehensive study of the properties of such a filamentary network. With this goal in mind, we perform an analysis of high-z gas and dark matter (DM) filaments around a Milky Way-like progenitor simulated with the ramses adaptive mesh refinement (AMR) code from cosmic scales (∼1 Mpc) down to the virial radius of its DM halo host (∼20 kpc at z = 4). Radial density profiles of both gas and DM filaments are found to have the same functional form, namely a plummer-like profile modified to take into account the wall within which these filaments are embedded. Measurements of the typical filament core radius r0 from the simulation are consistent with that of isothermal cylinders in hydrostatic equilibrium. Such an analytic model also predicts a redshift evolution for the core radius of filaments in fair agreement with the measured value for DM [r0∝ (1 + z)−3.18 ± 0.28]. Gas filament cores grow as [r0∝ (1 + z)−2.72 ± 0.26]. In both gas and DM, temperature and vorticity sharply drop at the edge of filaments, providing an excellent way to constrain the outer filament radius. When feedback is included, the gas temperature and vorticity fields are strongly perturbed, hindering such a measurement in the vicinity of the galaxy. However, the core radius of the filaments as measured from the gas density field is largely unaffected by feedback; and the median central density is only reduced by about 20 per cent.
Bank Concentration and Product Market Competition
Authors: Saidi Farzad , Streitz Daniel
Published: January 2021

This paper documents a link between bank concentration and markups in nonfinancial sectors. We exploit concentration-increasing bank mergers and variation in banks’ market shares across industries and show that higher credit concentration is associated with higher markups and that high-market-share lenders charge lower loan rates. We argue that this is due to the greater incidence of competing firms sharing common lenders that induce less aggressive product market behavior among their borrowers, thereby internalizing potential adverse effects of higher rates. Consistent with our conjecture, the effect is stronger in industries with competition in strategic substitutes where negative product market externalities are greatest.
Voluntary wheel running improves outcomes in an early life stress–induced model of urologic chronic pelvic pain syndrome in male mice
Authors: Fuentes Isabella M. , Jones Brittni M. , Brake Aaron D. , Pierce Angela N. , Eller Olivia C. , Supple Rachel M. , Wright Douglas E. , Christianson Julie A.
Published: January 2021

Patients with a history of early life stress (ELS) exposure have an increased risk of developing chronic pain and mood disorders later in life. The severity of ELS in patients with urologic chronic pelvic pain syndrome (UCPPS) is directly correlated with symptom severity and increased comorbidity, and is inversely related to likelihood of improvement. Voluntary exercise improves chronic pain symptoms, and our group and others have shown that voluntary wheel running can improve outcomes in stress-induced UCPPS models, suggesting that exercise may negate some of the outcomes associated with ELS. Here, we provide further evidence that voluntary wheel running can attenuate increased perigenital mechanical sensitivity, bladder output, and mast cell degranulation in the bladder and prostate in male mice that underwent neonatal maternal separation (NMS). Sedentary male NMS mice had reduced serum corticosterone, which was not impacted by voluntary wheel running, although stress-related regulatory gene expression in the hypothalamus and hippocampus was significantly increased after exercise. Neurogenesis in the dentate gyrus of the hippocampus was diminished in sedentary NMS mice and significantly increased in both exercised naïve and NMS mice. Sucrose consumption increased in exercised naïve but not NMS mice, and anxiety behaviors measured on an elevated plus maze were increased after exercise. Together these data suggest that voluntary wheel running is sufficient to normalize many of the UCPPS-related outcomes resulting from NMS. Exercise also increased hippocampal neurogenesis and stress-related gene expression within the hypothalamic–pituitary–adrenal axis, further supporting exercise as a nonpharmacological intervention for attenuating outcomes related to ELS exposure.
Relationship Between Retinal Layer Thickness and Disability Worsening in Relapsing-Remitting and Progressive Multiple Sclerosis
Authors: Cellerino Maria , Priano Luca , Bruschi Nicolò , Boffa Giacomo , Petracca Maria , Novi Giovanni , Lapucci Caterina , Sbragia Elvira , Uccelli Antonio , Inglese Matilde
Published: January 2021

Background:

Data regarding the predictive value of optical coherence tomography (OCT)-derived measures are lacking, especially in progressive multiple sclerosis (PMS). Accordingly, we aimed at investigating whether a single OCT assessment can predict a disability risk in both relapsing-remitting MS (RRMS) and PMS.

Methods:

One hundred one patients with RRMS and 79 patients with PMS underwent Spectral-Domain OCT, including intraretinal layer segmentation. All patients had at least 1 Expanded Disability Status Scale (EDSS) measurement during the subsequent follow-up (FU). Differences in terms of OCT metrics and their association with FU disability were assessed by analysis of covariance and linear regression models, respectively.

Results:

The median FU was 2 years (range 1–5.5 years). The baseline peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell + inner plexiform layer (GCIPL) were thinner in PMS compared with RRMS (P = 0.02 and P = 0.003, respectively). In the RRMS population, multivariable models showed that the GCIPL significantly correlated with FU disability (0.04 increase in the EDSS for each 1-μm decrease in the baseline GCIPL, 95% confidence interval: 0.006–0.08; P = 0.02). The baseline GCIPL was thinner in patients with RRMS with FU-EDSS >4 compared with those with FU-EDSS ≤4, and individuals in the highest baseline GCIPL tertile had a significantly lower FU-EDSS score than those in the middle and lowest tertile (P = 0.01 and P = 0.001, respectively). These findings were not confirmed in analyses restricted to patients with PMS.

Conclusions:

Among OCT-derived metrics, GCIPL thickness had the strongest association with short-medium term disability in patients with RRMS. The predictive value of OCT metrics in the longer term will have to be further investigated, especially in PMS.
Human cell-dependent, directional, time-dependent changes in the mono- and oligonucleotide compositions of SARS-CoV-2 genomes
Authors: Iwasaki Yuki , Abe Takashi , Ikemura Toshimichi
Published: January 2021

Background

When a virus that has grown in a nonhuman host starts an epidemic in the human population, human cells may not provide growth conditions ideal for the virus. Therefore, the invasion of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which is usually prevalent in the bat population, into the human population is thought to have necessitated changes in the viral genome for efficient growth in the new environment. In the present study, to understand host-dependent changes in coronavirus genomes, we focused on the mono- and oligonucleotide compositions of SARS-CoV-2 genomes and investigated how these compositions changed time-dependently in the human cellular environment. We also compared the oligonucleotide compositions of SARS-CoV-2 and other coronaviruses prevalent in humans or bats to investigate the causes of changes in the host environment.

Results

Time-series analyses of changes in the nucleotide compositions of SARS-CoV-2 genomes revealed a group of mono- and oligonucleotides whose compositions changed in a common direction for all clades, even though viruses belonging to different clades should evolve independently. Interestingly, the compositions of these oligonucleotides changed towards those of coronaviruses that have been prevalent in humans for a long period and away from those of bat coronaviruses.

Conclusions

Clade-independent, time-dependent changes are thought to have biological significance and should relate to viral adaptation to a new host environment, providing important clues for understanding viral host adaptation mechanisms.
Complex Systems Analysis Informs on the Spread of COVID-19
Authors: Wang Xia , Washington Dorcas , Weber Georg F.
Published: January 2021

The non-linear progression of new infection numbers in a pandemic poses challenges to the evaluation of its management. The tools of complex systems research may aid in attaining information that would be difficult to extract with other means. To study the COVID-19 pandemic, we utilize the reported new cases per day for the globe, nine countries and six US states through October 2020. Fourier and univariate wavelet analyses inform on periodicity and extent of change. Evaluating time-lagged data sets of various lag lengths, we find that the autocorrelation function, average mutual information and box counting dimension represent good quantitative readouts for the progression of new infections. Bivariate wavelet analysis and return plots give indications of containment versus exacerbation. Homogeneity or heterogeneity in the population response, uptick versus suppression, and worsening or improving trends are discernible, in part by plotting various time lags in three dimensions. The analysis of epidemic or pandemic progression with the techniques available for observed (noisy) complex data can aid decision making in the public health response.
Maribellus comscasissp. nov., isolated from the deep-sea cold seep
Authors: Zheng Rikuan , Sun Chaomin
Published: January 2021

A facultatively anaerobic, Gram-stain-negative, non-motile, curved rod-shaped bacterium, designated WC007T, was isolated from the deep-sea cold seep, P. R. China. Strain WC007Twas found to grow at temperatures from 28 to 37 °C (optimum, 30 °C), at pH values between pH 6.0 and 8.0 (optimum, pH 7.0) and in 0-5.0% (w/v) NaCl (optimum, 1.0%). The major fatty acids (>10.0%) were iso-C15:0, C16:0, summed feature 3 and summed feature 8. The major isoprenoid quinone was MK-7. Predominant polar lipids were phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid and one unidentified lipid. The G+C content of the genomic DNA was 38.38%. The average nucleotide identity (ANIb and ANIm), amino acid identity (AAI), the tetranucleotide signatures (Tetra) andin silicoDNA-DNA hybridization (isDDH) similarities between the genome sequences of isolate WC007TandMaribellus luteusXSD2Twere 70.11%, 84.94%, 71.0%, 0.92022 and 20.40%, respectively, indicating that strain WC007Twas distinguished fromM. luteus. Phylogenetic analysis based on 16S rRNA gene sequences placed strain WC007Twithin the genusMaribellusand showed the highest similarity to strain XSD2T(95.70%). In combination of the results of phylogenetic analysis and phenotypic and chemotaxonomic data, strain WC007Twas considered to represent a novel species of the genusMaribellus, for which the nameMaribellus comscasissp. nov. is proposed. The type strain is WC007T(=KCTC 25169T= MCCC 1K04777T). The available of the genome sequence of strain WC007Twould be helpful in understanding the degradation mechanism of difficult-to-degrade polysaccharides.
Coordination of phage genome degradation versus host genome protection by a bifunctional restriction-modification enzyme visualized by CryoEM
Authors: Shen Betty W. , Quispe Joel D. , Luyten Yvette , McGough Benjamin E. , Morgan Richard D. , Stoddard Barry L.
Published: January 2021

Restriction enzymes that combine DNA methylation and cleavage activities into a single polypeptide or protein assemblage and that modify just one DNA strand for host protection are capable of more efficient adaptation towards novel target sites. However, they must solve the problem of discrimination between newly replicated and unmodified host sites (needing methylation) and invasive foreign site (needing to lead to cleavage). One solution to this problem might be that the activity that occurs at any given site is dictated by the oligomeric state of the bound enzyme. Methylation requires just a single bound site and is relatively slow, while cleavage requires that multiple unmethylated target sites (often found in incoming, foreign DNA) be brought together into an enzyme-DNA complex to license rapid cleavage. To validate and visualize the basis for such a mechanism, we have determined the catalytic behavior of a bifunctional Type IIL restriction-modification (‘RM’) enzyme (DrdV) and determined its high-resolution structure at several different stages of assembly and coordination with multiple bound DNA targets using CryoEM. The structures demonstrate a mechanism of cleavage by which an initial dimer is formed between two DNA-bound enzyme molecules, positioning the single endonuclease domain from each enzyme against the other’s DNA and requiring further oligomerization through differing protein-protein contacts of additional DNA-bound enzyme molecules to enable cleavage. The analysis explains how endonuclease activity is licensed by the presence of multiple target-containing DNA duplexes and provides a clear view of the assembly through 3D space of a DNA-bound RM enzyme ‘synapse’ that leads to rapid cleavage of foreign DNA.
Investigating the role of social networking technology on the organizational agility: a structural equation modeling approach
Authors: Ahmadi Shadi , Ershadi Mohammad Javad
Published: January 2021

Purpose

The current extensive business ecosystem, characterized by technological advances and development, impressive customers, and increasing social concerns, has exerted great pressure on business organizations. Among different business values for affording this pressure, organizational agility is a critical factor that should be carefully incorporated in business processes. The main purpose of the present study is to investigate the role of social networking technology, as a crucial collaborative tool, on organizational agility.

Design/methodology/approach

A model based on structural equations was designed in this regard. The constructs of this model are quality of service, varieties of services, costs and speed of service as independent variables and also agility management as a dependent variable. Based on the conceptual model, a questionnaire was prepared and distributed among the experts of social networking technology and agility management. Based on Cochran's formula the sample size was 384. The response rate was 100%. The main statistical measures such as Chi-square ratio to the degree of freedom, Non-soft Fitness Index (RMSEA), Goodness of Fit Index (GFI) and Modified fitness index (AGFI) were employed for analyzing the model.

Findings

Results of obtained data indicated that a variety of services as the main factor of social networking technology has the most impact on the agility of a company. Then, the speed of service, service quality and costs were ranked respectively in second to fourth. Providing information technology (IT) service perceptions, promoting the service climate and thorough identification of IT requirements are the main critical success factors for maintaining a robust impact of social networking technology on organizational agility. Moreover, a well-designed enterprise structure alongside employing newly developed IT infrastructures such as cloud computing certainly improves the capabilities of organizations to improve their agility.

Originality/value

Although the literature suggests a positive impact among IT or social networks on organizational agility, it is deficient in relation to considering the impact of social networking. Furthermore, a structural equation model (SEM) is used for assessing unobservable latent constructs and their related interrelationship.
Navigating heutagogic learning: mapping the learning journey in management education through the OEPA model
Authors: Stoten David William
Published: January 2021

Purpose

The purpose of this conceptual paper is to advocate the adoption of heutagogic principles within management education and to show how it could be implemented.

Design/methodology/approach

This paper is the outcome of a review of the literature on learning theory and management education.

Findings

This paper demonstrates how heutagogic principles have been introduced in three areas: entrepreneurial education, executive coaching and e-learning.

Originality/value

This paper makes an original contribution to the discourse on heutagogy through the OEPA model that maps the heutagogic learning journey.
Welsh Devolution and the Union: Reform Debates after Brexit
Authors: Bradbury Jonathan
Published: January 2021

The survey addresses three key reform debates relating to devolution in Wales. These concern first, the case for the further devolution of powers, notably those over criminal justice and policing; second, the defence of Wales’ devolved powers in the context of Brexit; and third, the rooting of devolution in new constitutional ideals, primarily the Welsh government’s preferred model of the UK as a voluntary association of nations, or the alternative pressed by the independence movement. In each case, there are strong pressures within Wales for resolutions which sustain and develop devolution; and in the case of independence, have the potential, with reform debates elsewhere, to transform the UK Union. However, there are also grounds for reflecting on the contested nature of further change, the long road that a case for independence may yet have to travel, and the interests of UK government.
Discharge Prediction for Patients Undergoing Inpatient Surgery: Development and validation of the DEPENDENSE score
Authors: Hammer Maximilian , Althoff Friederike C. , Platzbecker Katharina , Wachtendorf Luca J. , Teja Bijan , Raub Dana , Schaefer Maximilian S. , Wongtangman Karuna , Xu Xinling , Houle Timothy T. , Eikermann Matthias , Murugappan Kadhiresan R.
Published: January 2021

Background

A substantial proportion of patients undergoing inpatient surgery each year is at risk for postoperative institutionalization and loss of independence. Reliable individualized preoperative prediction of adverse discharge can facilitate advanced care planning and shared decision making.

Methods

Using hospital registry data from previously home‐dwelling adults undergoing inpatient surgery, we retrospectively developed and externally validated a score predicting adverse discharge. Multivariable logistic regression analysis and bootstrapping were used to develop the score. Adverse discharge was defined as in‐hospital mortality or discharge to a skilled nursing facility. The model was subsequently externally validated in a cohort of patients from an independent hospital.

Results

In total, 106 164 patients in the development cohort and 92 962 patients in the validation cohort were included, of which 16 624 (15.7%) and 7717 (8.3%) patients experienced adverse discharge, respectively. The model was predictive of adverse discharge with an area under the receiver operating characteristic curve (AUC) of 0.87 (95% CI 0.87‐0.88) in the development cohort and an AUC of 0.86 (95% CI 0.86‐0.87) in the validation cohort.

Conclusion

Using preoperatively available data, we developed and validated a prediction instrument for adverse discharge following inpatient surgery. Reliable prediction of this patient centered outcome can facilitate individualized operative planning to maximize value of care.
Intra‐industry spill‐over effect of default: Evidence from the Chinese bond market
Authors: Hu Xiaolu , Luo Haoyi , Xu Zijin , Li Jiang
Published: January 2021

We investigate the intra‐industry spill‐over effect of defaults in the Chinese bond market by using a sample of public corporate debt securities for the period 2014–2018. We find that both industry portfolios and individual firms witness a strong contagion effect, which further spreads to the primary bond market, triggering a surge in the debt financing cost for default industries. Moreover, this contagion effect is stronger for low‐competition industries and regulated industries, as well as when a default happens to state‐owned enterprises. Better information access and higher bond liquidity alleviate the contagion effect, lending support to the information updates and liquidity dry‐up hypotheses.
Social group memberships, physical activity, and physical health following retirement: A six‐year follow‐up from the English Longitudinal Study of Ageing
Authors: Stevens Mark , Cruwys Tegan , Haslam Catherine , Wang Valerie
Published: January 2021

Objectives

To investigate whether belonging to more social groups supports people to be physically active following retirement and confers physical health benefits as a result.

Design

A longitudinal design was used, drawing on data spanning an eight‐year period from the English Longitudinal Study of Ageing.

Methods

In a population sample of retirees (N = 243), mediation models were used to examine relationships between number of post‐retirement group memberships, subsequent post‐retirement physical activity, and subsequent physical health.

Results

Belonging to a greater number of social groups predicted greater physical activity following retirement. More group memberships also consistently predicted both subjective and objective indicators of greater physical health via greater physical activity.

Conclusions

Supporting people to maintain – and ideally increase – their group memberships in retirement may have benefits for their engagement in physical activity and long‐term physical health.
Ocular manifestations of rosacea: A clinical review
Authors: Tavassoli Shokufeh , Wong Nathan , Chan Elsie
Published: January 2021

Ocular rosacea is a chronic inflammatory condition that can occur in the absence of cutaneous features. The most common ocular features are chronic blepharoconjunctivitis with eyelid margin inflammation and meibomian gland dysfunction. Corneal complications include corneal vascularization, ulceration, scarring and, rarely, perforation. Diagnosis is largely based on clinical signs, although it is often delayed in the absence of cutaneous changes, particularly in children. It can also be associated with systemic disorders such as cardiovascular disease. Management ranges from local therapy to systemic treatment, depending on the severity of the disease. In this review, we describe the epidemiology, pathophysiology, clinical features and treatment of rosacea and ocular rosacea.