bluuebunny/crossref_metadata_2025 huggingface dataset:
The Chemotaxis of Spermatozoa and its Questioned Occurrence in the Animal Kingdom
Authors: Dakin William J. , Fordham M. G. C.
Published: April 2021

The experiments fully detailed above need little summing-up, since the general result has been appended to each.

The discoveries may be tabulated as follows :-

Capillary tubes containing sea-water which has been in contact with ripe eggs of Echinus esculentus soon become plugged with spermatozoa when immersed in a sperm suspension. Control tubes containing normal sea-water, cœlomic fluid, sea-water of different PH and sea-water with immobilising reagents, etc., never contain anything like the same number of sperms as the egg-water tubes. The above result, obtained regularly, is quite contradictory to those of Buller and Loeb on other species of Echinoderms. From the general appearance of the accumulation of sperms, from the fact that a greater length was travelled in the egg-water tubes than in the others, and from the results with capillary tubes containing immobilising reagents, we consider that Echinus esculentus eggs give off substances which actually direct the sperm movements; in other words, that chemotaxis is demonstrated. The results of Experiments X. and XI. show that in all probability the accumulation of sperms in capillary tubes containing egg-water is due not only to chemotaxis, but also to other phenomena which it is known are produced by egg secretions (aggregation and agglutination of spermatozoa). The chemotactic action of egg-water seems to be specific. Egg-water of similar PH from Echinocardium cordatum had no effect upon sperms of Echinus esculentus. Possibly chemotaxis does not occur in all species of Echinoderms. This might explain the results of Buller and Loeb. It was not demonstrable in Teredo. Moreover, the experiments do not prove that the phenomenon is absolutely necessary for the fertilisation of eggs of Echinus esculentus. On the other hand, they would indicate that chemotaxis does occur in the animal kingdom, and in this respect they support the experiments of Lillie and de Meyer.
Absence of Prenatal Effects of Lens-Antibodies in Rabbits
Authors: Huxley J. S. , Carr-Saunders A. M.
Published: April 2021

The experiments of Guyer and Smith have attracted wide-spread attention. Their results are recorded in two papers (1918 and 1920). The first paper describes the injection of rabbit lens into fowls and the subsequent injection of the sensitised fowl serum so produced into pregnant does. Some of the young of the treated does exhibited certain abnormalities of the eye. No breeding experiments are recorded in this paper. In the second paper a similar series of experiments is described, as a result of which more abnormalities were produced. Breeding experiments with the abnormal young showed that the defects were inherited. In view of the interest which these experiments have aroused, it seemed desirable to repeat them, and this paper records an attempt to do so. The methods used by us were modelled on those employed by Guyer and Smith ; the particulars in which our methods differed from those of these two authors will be indicated in the description of our experiments and attention again drawn to them, so far as the matter seems relevant, in the comparison of our results with those of Guyer and Smith in the discussion which will follow.
Histological Studies on the Gonads of The Fowl
Authors: Fell Honor B.
Published: April 2021

(1) The so-called ‘luteal’ cells of the ovary are derived from the medullary cords of the embryo, as previously shown by Firket and Nonidez. The process, which appears to be a peculiar form of fatty infiltration, begins about the eleventh day of incubation. (2) Multiplication of the cells occurs in post-embryonic life and, as suggested by Nonidez, appears to take place not by mitosis but by a neoformation at the expense of certain epithelial elements in the stroma and ovarian thecae, which are derived from the distal extremities of the medullary cords. (3) The fully formed ‘luteal’ cell is seen to have a rather small spherical nucleus and vacuolated cytoplasm, which impregnates very deeply with the Mann-Kopsch and Da Fano techniques, and which contains blocks and granules of mitochondrial origin. With Benda’s stain fat can sometimes be demonstrated in the vacuoles. Golgi bodies are situated round the archoplasm. (4) The formation of ‘luteal’ cells in cases of sex reversal is found to be a repetition of the embryonic process. Sex cords are proliferated into the ovarian stroma and either give rise to seminiferous tubules or remain undifferentiated and form typical ‘luteal’ cells. In the latter case usually many of the neighbouring cords are degenerating. (5) The mode of origin of the ‘luteal’ tissue in the embryos, normal adult and cases of sex reversal, is difficult to reconcile with Morgan’s theory of the endocrine activity of these cells in relation to plumage. (6) In view of Geoffrey Smith’s work on Inachus and Sacculina, it is suggested that the exhibition of hen-feathering may possibly be due to a high lipoid content of the blood. On this assumption, the association of female plumage with the presence of ‘luteal’ cells in the gonad would be explicable, since inactive tissue such as the medullary cord cells would be more prone to fatty degeneration in such hen-feathered individuals. (7) It is thought that Pearl and Boring are mistaken in homologising the ‘luteal’ islets with the cells of the mammalian corpus luteum, since the numerous vacuolated cells of discharged and large atretic follicles are found to be mainly the product of fatty degeneration of ordinary connective tissue elements, while the yellow pigment seems to be derived from aborting blood vessels. This pigment is regarded as hsematoidin and is not found in the true ‘luteal’ cells.
Observations on Amoeba Feeding on The Ciliate Frontonia
Authors: Beers C. Dale
Published: April 2021

Amoeba occasionally feeds on the ciliate Frontonia. In the instances of feeding observed, the Frontonia was not ingested whole but was cut in half by the Amoeba. One half of the Frontonia is engulfed in a food cup of the Amoeba, the pseudopods of the cup producing an annular constriction in the middle region of the ciliate. The pseudopodial collar or cup flows distally and presses against the free half of the Frontonia. Thus the halves are pushed continuously farther apart, until the attenuated interconnecting strand is severed and one-half of the Frontonia is simultaneously engulfed.
Selective Production of 1,3-Butadiene from 1,3-Butanediol over Y2Zr2O7 Catalyst
Authors: Matsumura Yoshitaka , Matsuda Asami , Yamada Yasuhiro , Sato Satoshi
Published: April 2021

The vapor-phase dehydration of 1,3-butanediol (1,3-BDO) to produce 1,3-butadiene (BD) was investigated over yttrium zirconate, Y2Zr2O7, which was prepared through a hydrothermal aging process. 1,3-BDO was initially dehydrated to three unsaturated alcohols, namely 3-buten-2-ol, 3-buten-1-ol, and 2-buten-1-ol, followed by the further dehydration to BD. The catalytic activity of Y2Zr2O7 was strongly dependent on the calcination temperature. Furthermore, the reaction temperature was one of the important factors to produce BD efficiently: the selectivity to BD was increased with increasing reaction temperature up to 375 °C, while coke formation led to catalyst deactivation together with by-product formation at higher temperatures. Y2Zr2O7 catalyst calcined at 900 °C showed a high BD yield of 95% at 375 °C and a time on stream of 10 h.
Diagnostic efficacy of joint ultrasonography, dual-energy computed tomography and minimally invasive arthroscopy on knee gouty arthritis, a comparative study
Authors: Xie Yuesheng , Li Ling , Luo Riqiang , Xu Ting , Yang Lin , Xu Fangping , Lin Haobo , Zhang Guangfeng , Zhang Xiao
Published: April 2021

Objective:

This study aimed to investigate the diagnostic performance of minimally invasive arthroscopy for knee gout when comparing with joint ultrasonography and dual-energy computed tomography (DECT).

Methods:

From January 2016 to December 2018, 121 inpatients with knee joint swelling and pain were prospectively enrolled, including 63 gout patients and 58 non-gout patients. All patients underwent pre-operative ultrasonography and DECT to evaluate knee joint monosodium urate (MSU) deposits, followed by minimally invasive arthroscopy. The gold-standard for gout diagnosis was defined as the detection of MSU crystals in the synovial fluid under polarizing microscopic or pathological analysis.

Results:

The diagnostic results of ultrasonic double contour sign, hyperechogenic foci, MSU deposition (detected by DECT), MSU deposition (detected by arthroscopy) and MSU deposition in cartilage (detected by arthroscopy) were significantly associated with that of the gold-standard. Except for hyperechogenic foci, the other four indexes had high sensitivity and specificity (approximately or over 80%) and a large odds ratio (OR) (14.73 to 36.56), indicating good diagnostic performance. Detection of MSU deposition in cartilage by arthroscopy had a good diagnostic agreement with the ultrasonic double contour sign (κ = 0.711, p < 0.001).

Conclusion:

Joint ultrasonography, DECT, and minimally invasive arthroscopy had high sensitivity and specificity for the diagnosis of knee gouty arthritis. Minimally invasive arthroscopy was superior to joint ultrasonography and DECT, which can be a useful supplement for the diagnosis of gout.

Advances in knowledge:

This is the first study comparing the diagnostic performance for knee gout among the joint ultrasonography, DECT, and minimally invasive arthroscopy.
Side-by-side evaluation of virtual non-contrast and post-contrast images improves detection of clinically significant urolithiasis on single-phase split bolus dual-energy CT urography
Authors: Dodig Doris , Solocki Matić Tereza , Žuža Iva , Pavlović Ivan , Miletić Damir , Markić Dean
Published: April 2021

Objectives:

Studies show insufficient sensitivity of virtual non-contrast (VNC) reconstructions for stone detection in dual-energy CT urography (DE-CTU). The aim of this study was to investigate if side-by-side-evaluation of both VNC and post-contrast images could increase the sensitivity of single-phase split bolus DE-CTU.

Methods:

Consecutive patients with haematuria who underwent split bolus DE-CTU on the same dual-source DE-CT scanner were retrospectively enrolled in the study. Intravenous furosemide and oral hydration were employed. Two readers, independently and then jointly in two separate sessions, recorded the location and the longest axial stone diameter on three randomised sets of images: separate VNC and post-contrast images, and side-by-side-reconstructions. True non-contrast (TNC) images served as the standard of reference.

Results:

A total of 83 urinary stones were detected on TNC images. Independent reader side-by-side-evaluation of VNC and post-contrast images yielded higher stone detection sensitivity (76 and 84%, respectively) compared to evaluation of only VNC (71 and 81%, respectively) or post-contrast images (64 and 80%, respectively). The sensitivity of joint reader evaluation of side-by-side-images reached almost 86% and was not significantly different from TNC images (p = 0.77). All stones larger than 3 mm were correctly detected by side-by-side-evaluation. Dose reduction of 55% could be achieved by omitting TNC scans.

Conclusion:

Side-by-side-VNC and post-contrast image evaluation enable detection of clinically significant urolithiasis on single-phase split bolus DE-CTU with significant dose reduction.

Advances in knowledge:

This study shows that single-phase DE-CTU is feasible if VNC imaging is simultaneously utilised with post-contrast images.
Transarterial embolisation for gastroduodenal bleeding following endoscopic resection
Authors: Park Suyoung , Jeong Boryeong , Shin Ji Hoon , Jang Eun Ho , Hwang Jung Han , Kim Jeong Ho
Published: April 2021

Objectives:

Transcatheter arterial embolisation (TAE) is widely used to treat gastrointestinal bleeding. This paper reports the safety and efficacy of TAE for bleeding following endoscopic resection, including endoscopic mucosal resection and endoscopic submucosal dissection.

Methods:

Fifteen consecutive patients (13 males, two females; mean age 62.2 years) from two tertiary medical centres who underwent TAE for gastroduodenal bleeding after endoscopic resection from November 2001 to December 2020 were included. Patient demographics, clinical presentations, angiographic findings, and TAE details were retrospectively reviewed.

Results:

Immediate bleeding during endoscopic resection was noted in four patients. Delayed bleeding 1–30 days after endoscopic resection in nine patients presented with haematochezia (n = 4), haematemesis (n = 6) and melaena (n = 1). Endoscopic haemostasis was attempted in 11 patients (73.3%) but failed due to continued bleeding despite haemostasis (n = 6), failure to secure endoscopic field (n = 3) and unstable vital signs (n = 2). Eleven patients had positive angiographic findings for bleeding, and all bleeding arteries were embolised except one owing to failed superselection of the bleeder. In the other four patients with negative angiographic findings, the left gastric artery with/without the right gastric artery or the accessory left gastric artery was empirically embolised using gelatin sponge particles. Both technical and clinical success rates were 93.3% (14/15). No procedure-related complications occurred during follow-up.

Conclusions:

TAE is safe and effective in the treatment of immediate and delayed bleeding after endoscopic resection procedures.

Advances in knowledge:

This is the first and largest 20-year bicentric study published in English on this topic. Empirical TAE for angiographically negative bleeding sites was also effective without significant complications.
Transformaciones en los hábitos de comunicación y sociabilidad a través del incremento del uso de redes sociodigitales en tiempos de pandemia.
Authors: Cervantes Hernández Rubén , Chaparro-Medina Paola Margarita
Published: April 2021

Durante la pandemia que surgió a raíz de la enfermedad COVID-19 se implementaron medidas de seguridad que involucran el confinamiento y distanciamiento de la población. Esto tuvo como consecuencia la modificación de los estilos de vida de los individuos a través de las Tecnologías de la Información y Comunicación (TIC). Para efectos de esta investigación, nos centramos en las redes sociodigitales (RSD), siendo estas de importancia significativa para el desarrollo individual y organizacional. Por ello, se buscó contrastar el uso de diversas aplicaciones, antes y durante la pandemia, por medio de la implementación no probabilística de un cuestionario no longitudinal a la población mexicana, de entre diez a cuarenta años; con el objetivo de analizar el uso e interacción con sus dispositivos electrónicos. Dentro de los rubros del cuestionario se encuentran el incremento del tiempo en línea y las modificaciones en las prácticas de sociabilidad, adquisición y uso de nuevas aplicaciones y páginas para la conformación de un nuevo estilo de vida. Debido a esto, se consideró enfocar este estudio no experimental transeccional a la descripción del consumo de RSD durante la pandemia. Los resultados expresan un aumento significativo en el uso del internet, así como cambios en cuanto a la utilización de ciertas aplicaciones, al respecto de las actividades que realizan en línea en su mayoría aumentaron. En conclusión, ha aumentado el uso del internet generando nuevos procesos de interacción social, convirtiéndose, así, en un estilo de vida o parte de la cotidianeidad
Comunicación en el tercer sector antes y durante la Pandemia COVID 19: estrategias de comunicación en las redes sociales de las ONG de Blumenau, Santa Catarina, Brasil.
Authors: Durieux Zucco Fabricia , Machado Juliana , Morgana Boos de Quadros Cynthia , Foletto Fiuza Thamires
Published: April 2021

Communication in the third sector before and during the COVID 19 pandemic. Communication strategies on social networks of NGOs in Blumenau, Santa Catarina, Brazil
Cine de la crueldad y plataformas streaming: La erotización de la perversidad en las series mainstream Years and years y Chernobyl.
Authors: Fernández Rodríguez Carlos , Romero-Rodríguez Luis M. , Puebla Martínez Belén
Published: April 2021

Actualmente, alejados de aquellos tiempos de guerra entre el cine y la televisión de masas e inmersos en una cultura de las series cada vez más accesibles gracias a las plataformas streaming, las series empiezan a ser reconocidas como obras de arte que critican a las altas esferas de poder, signo propio de la tercera edad dorada de las series, y donde reside la verdadera originalidad audiovisual a ojos de las grandes audiencias en detrimento de un cine que parece cada vez más estancado o carente de interés. En plena revolución del panorama industrial del audiovisual, caracterizado por el éxito de las plataformas streaming, aparece un consumidor cada vez más democratizado, heterogéneo y cercano a la visión de “consumidor” más que de “espectador”. Adicionalmente, el audiovisual de masas recupera una visión perversa, hiperrealista, denunciativa y moralista que retrotrae al cine de la crueldad enunciado por André Bazin. Por todo ello, se diagnostica el fenómeno de la pornografía del horror, la estetización o la abyección cinematográfica, ya debatida por Jackes Rivette y Serge Daney en la segunda mitad del siglo XX, con el objeto de unir lo depresivo con el espectáculo en series actuales. Por todo ello, se ha procedido a la realización de un estudio de casos, mediante un análisis de carácter exploratorio y descriptivo, de las series Years and years y Chernobyl a fin de diagnosticar la presencia de una narrativa de prestigio en las plataformas streaming que cumplen como abyectas bajo el simulacro de lo denunciativo.
El ciberactivismo, nueva forma de movilización social en la campaña del boicot comercial en Marruecos.
Authors: IRAKRAK NASMA
Published: April 2021

La campaña del boicot comercial en Marruecos ha dado lugar a una realidad en la que la tecnología y el activismo se han dado la mano para crear una estrategia de movilización social exitosa. El reclamo de la sociedad utilizó las nuevas tecnologías para, de forma inédita, producir un boicot comercial sustentado únicamente en el ciberactivismo. De esta forma se hicieron visibles los indicios de un cambio social latente y de una implicación comunitaria y tecnológica considerable surgidos a través de la llamada “Primavera Árabe”. En el presente artículo se analizan las prácticas tecno comunicativas efectuadas durante la campaña del boicot comercial en Marruecos, conocidas como «#moqatioune (boicoteamos)» que pretendió movilizar a la población marroquí llamándola a participar e implicarse en dicha campaña. Para llevar a cabo este estudio se ha adoptado una metodología cuantitativa del análisis del contenido. De esta manera se ha estudiado el elemento tecno comunicativo, la narrativa expuesta y la interacción continua de mensajes, potenciados por el poder de las nuevas tecnologías, especialmente la red social Facebook, durante la campaña del boicot comercial. Los resultados principales de este estudio han demostrado que el éxito de la campaña se debe fundamentalmente a la eficacia de las estrategias de movilización. El uso de las nuevas tecnologías de la comunicación, han demostrado ser un instrumento poderoso para expandir la información, visibilizar, influir y convocar las protestas.
Resonance-enhanced high harmonic in metal ions driven by elliptically polarized laser pulses
Authors: Lai Yu Hang , Rao Konda Srinivasa , Liang Jingguang , Wang Xu , Guo Chunlei , Yu Weili , Li Wei
Published: April 2021

Resonance enhancement of a single order harmonic has been a main attractive feature in high-harmonic generation from laser ablated plumes of metals. Although it has been extensively investigated experimentally and theoretically, studies so far have focused only on linearly polarized driving fields. In this Letter, we study the dependence of the resonant harmonic yield in tin ions on the driving laser ellipticity. We find that the resonance leads to a less rapid decay of the harmonic yield as a function of driving ellipticity, and it is qualitatively reproduced by quantum mechanical simulations. To the best of our knowledge, our findings provide a new type of evidence for supporting previously proposed mechanisms for enhancement.
Photoacoustic-fluorescence microendoscopy in vivo
Authors: Yang Wenzhao , Zhou Jiasheng , Shao Weihao , Seong Myeongsu , He Pengbo , Ye Zhanhong , Guo Zhendong , Jing Lili , Chen Sung-Liang
Published: April 2021

A miniature endoscope capable of imaging multiple tissue contrasts in high resolution is highly attractive, because it can provide complementary and detailed tissue information of internal organs. Here we present a photoacoustic (PA)-fluorescence (FL) endoscope for optical-resolution PA microscopy (PAM) and FL microscopy (FLM). The endoscope with a diameter of 2.8 mm achieves high lateral resolutions of 5.5 and 6.3 µm for PAM and FLM modes, respectively. In vivo imaging of zebrafish larvae and a mouse ear is conducted, and high-quality images are obtained. Additionally, in vivo endoscopic imaging of a rat rectum is demonstrated, showing the endoscopic imaging capability of our endoscope. By providing dual contrasts with high resolution, the endoscope may open up new opportunities for clinical endoscopic imaging applications.
Photonic chip-based resonant supercontinuum via pulse-driven Kerr microresonator solitons
Authors: Anderson Miles H. , Bouchand Romain , Liu Junqiu , Weng Wenle , Obrzud Ewelina , Herr Tobias , Kippenberg Tobias J.
Published: April 2021

Supercontinuum generation and soliton microcomb formation both
represent key techniques for the formation of coherent, ultrabroad
optical frequency combs, enabling the RF-to-optical link. Coherent
supercontinuum generation typically relies on ultrashort pulses with
kilowatt peak power as a source, and so are often restricted to
repetition rates less than 1 GHz. Soliton microcombs, conversely, have
an optical conversion efficiency that is best at ultrahigh repetition
rates such as 1 THz. Neither technique easily approaches the microwave
domain, i.e., 10 s of GHz, while maintaining an ultrawide spectrum.
Here, we bridge the efficiency gap between the two approaches in the
form of resonant supercontinuum generation by driving a
dispersion-engineered photonic-chip-based microresonator with
picosecond pulses of the order of 1-W peak power. We generate a smooth
2200-line soliton-based comb at an electronically detectable 28 GHz
repetition rate. Importantly, we observe that solitons exist in a
weakly bound state with the input pulse where frequency noise transfer
from the input pulses is suppressed even for offset frequencies 100
times lower than the linear cavity decay rate. This transfer can be
reduced even further by driving the cavity asynchronously, ensuring
the frequency comb stays coherent even for optical lines very far from
the pump center.
Data-based Customer-Retention-as-a-Service: Induktive Entwicklung eines datenbasierten Geschäftsmodells auf Basis einer Fallstudie der Automobilbranche
Authors: Kortum Henrik , Rebstadt Jonas , Gravemeier Laura Sophie , Thomas Oliver
Published: April 2021

Viele Unternehmen setzen Künstliche Intelligenz zur Verarbeitung großer Datenmengen bereits heute erfolgreich für die Kundenbindung ein. So schaffen große Unternehmen individuelle Kundenerlebnisse basierend auf der Auswertung großer kundenbezogener Datenmengen zur kurz- aber auch langfristigen Kundenbindung, z. B. durch intelligente Empfehlungen von Inhalten auf Videoplattformen. Bei Unternehmen mit traditioneller Wertschöpfung wird dieses Potenzial jedoch noch nicht ausreichend genutzt. Vor diesem Hintergrund wird im Rahmen einer Fallstudie exemplarisch ein datengetriebenes Kundenbindungsszenario in Kooperation mit einer Autowerkstatt umgesetzt. Im konkreten Fall wurde eine zeitlich optimierte Kundenansprache auf Basis von KI-basierten Prognosen der täglichen Fahrleistung von Kunden angestrebt. Grundlage dafür war die Analyse eines Kundendatensatzes einer Autowerkstatt und die anschließende Entwicklung einer Künstlichen Intelligenz. Aufbauend auf der Fallstudie wird ein datenbasiertes Geschäftsmodell konzipiert, dessen Werteangebot vor allem Unternehmen mit traditioneller Wertschöpfung und wenig Wissen im Bereich Künstlicher Intelligenz dazu befähigt, datenbasierte Technologien in der Kundenbindung einzusetzen. Das dem Geschäftsmodell zugrundeliegende Plattformkonzept wird dabei als Open-Innovation-Modell entwickelt und soll neben der Entwicklung eigener Services auch die Interaktion von Datenkonsumenten, Datenlieferanten und anderen Datenbefähigern, mit dem Ziel sich als Datenökosystem für Kundenbindung zu etablieren, unterstützen.
Akzeptanz von Distance Working bei Führungskräften
Authors: Bergsleitner Florian , Rückel David
Published: April 2021

Geänderte Anforderungen an die Arbeitsplätze durch die globale Covid-Krise bedingen Veränderungen des Führungsstils. Losgelöst von althergebrachten Kontrollinstanzen definieren moderne Führungskräfte ihren Stil als „Digital Leader“ wesentlich umfassender und sind essenzieller Enabler, um Distance Working in Unternehmen zu etablieren. Obwohl Ressentiments gegen die Schaffung von Arbeitsplätzen im Distance Working bestehen, nehmen Führungskräfte gleichermaßen die Verantwortung für ihre Mitarbeiter und die Unternehmen wahr. Entsprechend ist es Ziel dieses Beitrags, die Bedenken und Herausforderungen von Führungskräften in Bezug auf Digital Leadership und Distance Working zu erheben und mittels Design Science aus dem aktuellen „State of the Field“ wissenschaftlicher Literatur verbunden mit einer beispielhaften Umsetzung ein Konzept zur Steigerung der Akzeptanz von Distance Working zu erstellen. Das entstandene Artefakt wird durch Interviews mit zehn Experten evaluiert. Technische Lösungen werden als Grundbedingung angesehen, die Vertrauenskultur deutlich stärker gelebt als dies von vorangegangen Stilen bekannt war. Führungskräfte empfinden beim Digital Leadership keinen Kontrollverlust, sie bringen den MitarbeiterInnen Vertrauen entgegen und monitoren deren Leistungen. Die Kommunikation wird um die außerdienstliche, soziale Komponente erweitert, da Führungskräfte erkennen, dass Mitarbeiterführung damit vertrauensvoller gelingen kann. Um das Unternehmen weiterhin gut am Markt positionieren und zukunftsorientiert agieren zu können, wünschen sich Führungskräfte im Gesetzgeber einen starken Verbündeten, der den Rahmen so gestaltet, dass sowohl Schutz des Mitarbeiters wie auch individuelle Lösungen gewährleistet bleiben.
A new model for simultaneous dimensionality reduction and time-varying functional connectivity estimation
Authors: Vidaurre Diego
Published: April 2021

An important question in neuroscience is whether or not we can interpret spontaneous variations in the pattern of correlation between brain areas, which we refer to as functional connectivity or FC, as an index of dynamic neuronal communication in fMRI. That is, can we measure time-varying FC reliably? And, if so, can FC reflect information transfer between brain regions at relatively fast-time scales? Answering these questions in practice requires dealing with the statistical challenge of having high-dimensional data and a comparatively lower number of time points or volumes. A common strategy is to use PCA to reduce the dimensionality of the data, and then apply some model, such as the hidden Markov model (HMM) or a mixture model of Gaussian distributions, to find a set of distinct FC patterns or states. The distinct spatial properties of these FC states together with the time-resolved switching between them offer a flexible description of time-varying FC. In this work, I show that in this context PCA can suffer from systematic biases and loss of sensitivity for the purposes of finding time-varying FC. To get around these issues, I propose a novel variety of the HMM, named HMM-PCA, where the states are themselves PCA decompositions. Since PCA is based on the data covariance, the state-specific PCA decompositions reflect distinct patterns of FC. I show, theoretically and empirically, that fusing dimensionality reduction and time-varying FC estimation in one single step can avoid these problems and outperform alternative approaches, facilitating the quantification of transient communication in the brain.
Tempo and mode in karyotype evolution revealed by a probabilistic model incorporating both chromosome number and morphology
Authors: Yoshida Kohta , Kitano Jun
Published: April 2021

Karyotype, including the chromosome and arm numbers, is a fundamental genetic characteristic of all organisms and has long been used as a species-diagnostic character. Additionally, karyotype evolution plays an important role in divergent adaptation and speciation. Centric fusion and fission change chromosome numbers, whereas the intra-chromosomal movement of the centromere, such as pericentric inversion, changes arm numbers. A probabilistic model simultaneously incorporating both chromosome and arm numbers has not been established. Here, we built a probabilistic model of karyotype evolution based on the “karyograph”, which treats karyotype evolution as a walk on the two-dimensional space representing the chromosome and arm numbers. This model enables analysis of the stationary distribution with a stable karyotype for any given parameter. After evaluating their performance using simulated data, we applied our model to two large taxonomic groups of fish, Eurypterygii and series Otophysi, to perform maximum likelihood estimation of the transition rates and reconstruct the evolutionary history of karyotypes. The two taxa significantly differed in the evolution of arm number. The inclusion of speciation and extinction rates demonstrated possibly high extinction rates in species with karyotypes other than the most typical karyotype in both groups. Finally, we made a model including polyploidization rates and applied it to a small plant group. Thus, the use of this probabilistic model can contribute to a better understanding of tempo and mode in karyotype evolution and its possible role in speciation and extinction.
Dynamic post-transcriptional regulation by Mrn1 links cell wall homeostasis to mitochondrial structure and function
Authors: Reynaud Kendra , Brothers Molly , Ly Michael , Ingolia Nicholas T.
Published: April 2021

The RNA-binding protein Mrn1 inSaccharomyces cerevisiaetargets over 300 messenger RNAs, including many involved in cell wall biogenesis. The impact of Mrn1 on these target transcripts is not known, however, nor is the cellular role for this regulation. We have shown that Mrn1 represses target mRNAs through the action of its disordered, asparagine-rich amino-terminus. Its endogenous targets include the paralogous SUN domain proteins Nca3 and Uth1, which affect mitochondrial and cell wall structure and function. While loss ofMRN1has no effect on fermentative growth, we found thatmrn1Δyeast adapt more quickly to respiratory conditions. These cells also have enlarged mitochondria in fermentative conditions, mediated in part by dysregulation ofNCA3, and this may explain their faster switch to respiration. Our analyses indicated that Mrn1 acts as a hub for integrating cell wall integrity and mitochondrial biosynthesis in a carbon-source responsive manner.
Aicardi-Goutières syndrome-associated gene SAMHD1 preserves genome integrity by preventing R-loop formation at transcription–replication conflict regions
Authors: Park Kiwon , Ryoo Jeongmin , Jeong Heena , Kim Minsu , Lee Sungwon , Hwang Sung-Yeon , Ahn Jiyoung , Kim Doyeon , Moon Hyungseok C. , Baek Daehyun , Kim Kwangsoo , Park Hye Yoon , Ahn Kwangseog
Published: April 2021

The comorbid association of autoimmune diseases with cancers has been a major obstacle to successful anti-cancer treatment. Cancer survival rate decreases significantly in patients with preexisting autoimmunity. However, to date, the molecular and cellular profiles of such comorbidities are poorly understood. We used Aicardi-Goutières syndrome (AGS) as a model autoimmune disease and explored the underlying mechanisms of genome instability in AGS-associated-gene-deficient patient cells. We found that R-loops are highly enriched at transcription-replication conflict regions of the genome in fibroblast of patients bearing SAMHD1 mutation, which is the AGS-associated-gene mutation most frequently reported with tumor and malignancies. In SAMHD1-depleted cells, R-loops accumulated with the concomitant activation of DNA damage responses. Removal of R-loops in SAMHD1 deficiency reduced cellular responses to genome instability. Furthermore, downregulation of SAMHD1 expression is associated with various types of cancer and poor survival rate. Our findings suggest that SAMHD1 functions as a tumor suppressor by resolving R-loops, and thus, SAMHD1 and R-loop may be novel diagnostic markers and targets for patient stratification in anti-cancer therapy.
Control of scabies in a tribal community using mass screening and treatment with oral ivermectin -A cluster randomized controlled trial in Gadchiroli, India
Authors: Behera Priyamadhaba , Munshi Hrishikesh , Kalkonde Yogeshwar , Deshmukh Mahesh , Bang Abhay
Published: April 2021

Background

Scabies is often endemic in tribal communities and difficult to control. We assessed the efficacy of a community-based intervention using mass screening and treatment with oral ivermectin in controlling scabies.

Methods/ Findings

In this cluster randomised controlled trial, 12 villages were randomly selected from a cluster of 42 tribal villages in Gadchiroli district. In these villages, trained community health workers (CHWs) conducted mass screening for scabies. The diagnosis was confirmed by a physician. Six villages each were randomly allocated to the intervention and usual care arm (control arm). In the intervention arm (population 1184) CHWs provided directly observed oral ivermectin to scabies cases and their household contacts. In the usual care arm (population 1567) scabies cases were referred to the nearest clinic for topical treatment as per the standard practice. The primary outcome was prevalence of scabies two months after the treatment. Secondary outcomes were prevalence of scabies after twelve months of treatment and prevalence of impetigo after two and twelve months of treatment. Outcomes were measured by the team in a similar way as the baseline. The trial was registered with the clinical trial registry of India, number CTRI/2017/01/007704.

In the baseline, 2 months and 12 months assessments 92.4%, 96% and 94% of the eligible individuals were screened in intervention villages and 91.4%, 91.3% and 95% in the usual care villages. The prevalence of scabies in the intervention and usual care arm was 8.4% vs 8.1% at the baseline, 2.8% vs 8.8% at two months [adjusted relative risk (ARR) 0.21, 95% CI 0.11–0.38] and 7.3% vs 14.1% (ARR 0.49, 95% CI 0.25–0.98) at twelve months The prevalence of impetigo in the intervention and usual care arm was 1.7% vs 0.6% at baseline, 0.6% vs 1% at two months (ARR 0.55, 95% CI 0.22–1.37) and 0.3% vs 0.7% at 12 months (ARR 0.42, 95% CI 0.06–2.74). Adverse effects due to ivermectin occurred in 12.1% of patients and were mild.

Conclusions

Mass screening and treatment in the community with oral ivermectin delivered by the CHWs is superior to mass screening followed by usual care involving referral to clinic for topical treatment in controlling scabies in this tribal community in Gadchiroli.
Determinants of burnout and other aspects of psychological well-being in healthcare workers during the Covid-19 pandemic: A multinational cross-sectional study
Authors: Denning Max , Goh Ee Teng , Tan Benjamin , Kanneganti Abhiram , Almonte Melanie , Scott Alasdair , Martin Guy , Clarke Jonathan , Sounderajah Viknesh , Markar Sheraz , Przybylowicz Jan , Chan Yiong Huak , Sia Ching-Hui , Chua Ying Xian , Sim Kang , Lim Lucas , Tan Lifeng , Tan Melanie , Sharma Vijay , Ooi Shirley , Winter Beatty Jasmine , Flott Kelsey , Mason Sam , Chidambaram Swathikan , Yalamanchili Seema , Zbikowska Gabriela , Fedorowski Jaroslaw , Dykowska Grazyna , Wells Mary , Purkayastha Sanjay , Kinross James
Published: April 2021

The Covid-19 pandemic has placed unprecedented pressure on healthcare systems and workers around the world. Such pressures may impact on working conditions, psychological wellbeing and perception of safety. In spite of this, no study has assessed the relationship between safety attitudes and psychological outcomes. Moreover, only limited studies have examined the relationship between personal characteristics and psychological outcomes during Covid-19. From 22nd March 2020 to 18th June 2020, healthcare workers from the United Kingdom, Poland, and Singapore were invited to participate using a self-administered questionnaire comprising the Safety Attitudes Questionnaire (SAQ), Oldenburg Burnout Inventory (OLBI) and Hospital Anxiety and Depression Scale (HADS) to evaluate safety culture, burnout and anxiety/depression. Multivariate logistic regression was used to determine predictors of burnout, anxiety and depression. Of 3,537 healthcare workers who participated in the study, 2,364 (67%) screened positive for burnout, 701 (20%) for anxiety, and 389 (11%) for depression. Significant predictors of burnout included patient-facing roles: doctor (OR 2.10; 95% CI 1.49–2.95), nurse (OR 1.38; 95% CI 1.04–1.84), and ‘other clinical’ (OR 2.02; 95% CI 1.45–2.82); being redeployed (OR 1.27; 95% CI 1.02–1.58), bottom quartile SAQ score (OR 2.43; 95% CI 1.98–2.99), anxiety (OR 4.87; 95% CI 3.92–6.06) and depression (OR 4.06; 95% CI 3.04–5.42). Significant factors inversely correlated with burnout included being tested for SARS-CoV-2 (OR 0.64; 95% CI 0.51–0.82) and top quartile SAQ score (OR 0.30; 95% CI 0.22–0.40). Significant factors associated with anxiety and depression, included burnout, gender, safety attitudes and job role. Our findings demonstrate a significant burden of burnout, anxiety, and depression amongst healthcare workers. A strong association was seen between SARS-CoV-2 testing, safety attitudes, gender, job role, redeployment and psychological state. These findings highlight the importance of targeted support services for at risk groups and proactive SARS-CoV-2 testing of healthcare workers.
Establishing defined daily doses (DDDs) for antimicrobial agents used in pigs, cattle and poultry in Japan and comparing them with European DDD values
Authors: Fujimoto Kyoko , Kawasaki Mai , Abe Reiko , Yokoyama Takashi , Haga Takeshi , Sugiura Katsuaki
Published: April 2021

Monitoring of antimicrobial use is essential in the management of the development and selection of antimicrobial resistance. A variety of indicators has become available to monitor antimicrobial use in human and animal medicine. One of them is an indicator based on defined daily dose (DDD). By using the number of DDDs administered and normalising it by the population at risk of being treated over a defined period, one can estimate the number of treatment days with antimicrobial agents in a population. For veterinary medicine, the European Medicines Agency (EMA) has published the European values of DDD (DDDvet) for food-producing animals. In this study, we defined Japanese defined daily doses for antimicrobial agents (DDDjp) using DDD values that we previously assigned for antimicrobial products approved for use in pigs, cattle and poultry in Japan and compared them with DDDvet values. For the comparison, the quotient of Japanese and European values (QDDD) was calculated and the effect of the administration route and the number of active substances contained in the preparation was investigated. A total of 59 DDDjp values were defined for 43 antimicrobial agents using the data of 276 products approved for use in pigs. Likewise, a total of 55 DDDjp values were defined for 32 antimicrobial agents using the data of 196 products for use in cattle, and a total of 27 DDDjps values were defined for 25 antimicrobial agents using the data of 131 products approved for use in poultry. A comparison was made for 42, 28 and 17 pairs of DDDjp and DDDvet values for antimicrobial agents used for pigs, cattle and poultry respectively. The comparison showed median QDDD value of 0.61 and 0.66 for antimicrobial agents used for pigs and cattle respectively (p<0.01), indicating that the Japanese daily doses are significantly lower than the corresponding EMA values in these species. For the antimicrobial agents used for poultry, no significant difference was observed between DDDjp and DDDvet values with a median QDDD value of 1.15. The difference between DDDvet and DDDjp values and absence of DDDvet values for some antimicrobial agents marketed in Japan indicate that DDDjp rather than DDDvet should be used as the basis for the calculation of antimicrobial use monitoring in farm animals in Japan.
A framework model using multifilter feature selection to enhance colon cancer classification
Authors: Al-Rajab Murad , Lu Joan , Xu Qiang
Published: April 2021

Gene expression profiles can be utilized in the diagnosis of critical diseases such as cancer. The selection of biomarker genes from these profiles is significant and crucial for cancer detection. This paper presents a framework proposing a two-stage multifilter hybrid model of feature selection for colon cancer classification. Colon cancer is being extremely common nowadays among other types of cancer. There is a need to find fast and an accurate method to detect the tissues, and enhance the diagnostic process and the drug discovery. This paper reports on a study whose objective has been to improve the diagnosis of cancer of the colon through a two-stage, multifilter model of feature selection. The model described deals with feature selection using a combination of Information Gain and a Genetic Algorithm. The next stage is to filter and rank the genes identified through this method using the minimum Redundancy Maximum Relevance (mRMR) technique. The final phase is to further analyze the data using correlated machine learning algorithms. This two-stage approach, which involves the selection of genes before classification techniques are used, improves success rates for the identification of cancer cells. It is found that Decision Tree, K-Nearest Neighbor, and Naïve Bayes classifiers had showed promising accurate results using the developed hybrid framework model. It is concluded that the performance of our proposed method has achieved a higher accuracy in comparison with the existing methods reported in the literatures. This study can be used as a clue to enhance treatment and drug discovery for the colon cancer cure.
Photosynthetic apparatus performance of tomato seedlings grown under various combinations of LED illumination
Authors: Yousef Ahmed F. , Ali Muhammad M. , Rizwan Hafiz M. , Tadda Shehu Abubakar , Kalaji Hazem M. , Yang Hao , Ahmed Mohamed A. A. , Wróbel Jacek , Xu Yong , Chen Faxing
Published: April 2021

It is already known that the process of photosynthesis depends on the quality and intensity of light. However, the influence of the new light sources recently used in horticulture, known as Light Emitting Diodes (LEDs), on this process is not yet fully understood. Chlorophyll a fluorescence measurement has been widely used as a rapid, reliable, and noninvasive tool to study the efficiency of the photosystem II (PSII) and to evaluate plant responses to various environmental factors, including light intensity and quality. In this work, we tested the responses of the tomato photosynthetic apparatus to different light spectral qualities. Our results showed that the best performance of the photosynthetic apparatus was observed under a mixture of red and blue light (R7:B3) or a mixture of red, green and blue light (R3:G2:B5). This was demonstrated by the increase in the effective photochemical quantum yield of PSII (Y[II]), photochemical quenching (qP) and electron transport rate (ETR). On the other hand, the mixture of red and blue light with a high proportion of blue light led to an increase in non-photochemical quenching (NPQ). Our results can be used to improve the production of tomato plants under artificial light conditions. However, since we found that the responses of the photosynthetic apparatus of tomato plants to a particular light regime were cultivar-dependent and there was a weak correlation between the growth and photosynthetic parameters tested in this work, special attention should be paid in future research.
The presence of Wormian bones increases the fracture resistance of equine cranial bone
Authors: Zambrano M. Lilibeth A. , Kilroy David , Kumar Arun , Gilchrist Michael D. , Ní Annaidh Aisling
Published: April 2021

Wormian (intrasutural) bones are small, irregular bones, that are found in the cranial sutures of the skull. The occurrence of Wormian bones in human skulls has been well documented but few studies have detected the presence of such bones in domestic animals. Although some research has linked the presence of Wormian bones to bone pathology, its anatomical significance in healthy individuals is not known. To the best of our knowledge, no previous study has examined the biomechanical features of Wormian bone. This study uses microCT imaging of the parietal bone region to determine the frequency of occurrence of Wormian bones in horse skulls and, through 3-point bending tests, to calculate the mechanical differences that result from the presence of such bones. In addition, bone properties such as bone mineral density (BMD) and stiffness were measured and analysed to determine the influence of Wormian bone. Our findings on 54 specimens taken from 10 horses (ages ranging from 4 to 29 years) showed that Wormian bone was present in 70% of subjects and that its occurrence was unrelated to age or sex. 3-point bend tests revealed that the stiffness normalised by cross section area (P = 0.038) was lower in samples where Wormian bone was present. An idealised Finite Element simulation confirmed that the presence of Wormian bone reduced the maximum stress and strain, as well as their distribution throughout the sample. We consequently conclude that the presence of Wormian bones, which are confined to the calvaria, increase the compliance of the bone and reduce the likelihood of skull fracture. As all skull samples were collected from a local abattoir, ethical approval was not required for this work.
The bone bridge significantly affects the decrease in bone mineral density measured with quantitative computed tomography in ankylosing spondylitis
Authors: Lee So Yun , Song Ran , Yang Hyung In , Chung Sang Wan , Lee Yeon-Ah , Hong Seung-Jae , Yun Seong Jong , Lee Sang-Hoon
Published: April 2021

Introduction and objective

Ankylosing spondylitis (AS) has characteristics of spinal bone bridge and fusion. Although BMD reduction in AS may be presumed to be due to spinal inflammation, this study was designed to confirm whether immobilization of the spine due to syndesmophytes is related to BMD reduction, as immobilization itself is a risk factor for BMD reduction.

Methods

Among male patients diagnosed with AS according to the modified New York criteria, those who underwent bone density tests with quantitative computed tomography (QCT) were retrospectively analyzed through a chart review. The correlation between the presence or absence of bone bridges for each vertebral body level of the L spine confirmed with radiography and BMD confirmed with QCT was analyzed.

Results

A total of 47 male patients with AS were enrolled. The mean patient age was 46.8 ± 8.2 years, and the mean disease duration was 7.9 ± 6.4 years. The trabecular BMD of the lumbar spine (L1-L4) ranged from 23.1 to 158.45 mg/cm3 (mean 102.2 ± 37 mg/cm3), as measured with QCT. The lumbar BMD measurements showed that 30 patients (63.8%) had osteopenia or osteoporosis. Bone bridge formation showed a negative correlation with BMD. Low BMD was significantly correlated with bone bridge in the vertebral body (p < 0.05). Positive correlations were observed between bone bridge score and BASMI flexion score, whereas significant negative correlations were found between BMD and BASMI flexion score (p < 0.05).

Conclusion

Decreased mobility of the vertebrae due to bone bridge formation affects the decrease in BMD in patients with AS.