bluuebunny/crossref_metadata_2025 huggingface dataset:
Age-specific shifts in Greenland halibut (Reinhardtius hippoglossoides) distribution in response to changing ocean climate
Authors: Wheeland Laura J , Morgan M Joanne
Published: July 2019

Fish distribution is strongly influenced by temperature, with populations predicted to respond to ongoing changes in ocean climate by adapting distribution to maintain preferred thermal habitats. Over the last several decades, the Northwest Atlantic off Newfoundland, Canada has experienced wide variation in temperature and significant changes in the structure of the marine community. A period of particularly cold ocean conditions from the mid-1980s to mid-1990s saw Greenland halibut occupying deeper waters, and moving farther offshore and southward. Distributional shifts across periods of varying thermal conditions were most pronounced in the youngest ages. While no specific nursery areas were evident, these young fish typically occurred in shallower waters where temperatures were more variable, moving deeper with age. Sensitivity to changing ocean climate may vary with age. This adaptation to shifting temperatures suggests that this species is likely to alter its distribution in the face of continued changes in ocean climate. Age-specific differences in response to changing temperature have potential implications for ecosystem interactions and fisheries management.
Resolutions With Conical Slices and Descent for the Brauer Group Classes of Certain Central Reductions of Differential Operators in Characteristicp
Authors: Kubrak Dmitry , Travkin Roman
Published: July 2019

“Even more so is the word ‘crystalline’, a glacial and impersonal concept of his which disdains viewing existence from a single portion of time and space” Eileen Myles, “The Importance of Being Iceland”

For a smooth variety $X$ over an algebraically closed field of characteristic $p$ to a differential 1-form $\alpha $ on the Frobenius twist $X^{\textrm{(1)}}$ one can associate an Azumaya algebra ${{\mathcal{D}}}_{X,\alpha }$, defined as a certain central reduction of the algebra ${{\mathcal{D}}}_X$ of “crystalline differential operators” on $X$. For a resolution of singularities $\pi :X\to Y$ of an affine variety $Y$, we study for which $\alpha $ the class $[{{\mathcal{D}}}_{X,\alpha }]$ in the Brauer group $\textrm{Br}(X^{\textrm{(1)}})$ descends to $Y^{\textrm{(1)}}$. In the case when $X$ is symplectic, this question is related to Fedosov quantizations in characteristic $p$ and the construction of noncommutative resolutions of $Y$. We prove that the classes $[{{\mathcal{D}}}_{X,\alpha }]$ descend étale locally for all $\alpha $ if ${{\mathcal{O}}}_Y\widetilde{\rightarrow }\pi _\ast{{\mathcal{O}}}_X$ and $R^{1}\pi _*\mathcal O_X = R^2\pi _*\mathcal O_X =0$. We also define a certain class of resolutions, which we call resolutions with conical slices, and prove that for a general reduction of a resolution with conical slices in characteristic $0$ to an algebraically closed field of characteristic $p$ classes $[{{\mathcal{D}}}_{X,\alpha }]$ descend to $Y^{\textrm{(1)}}$ globally for all $\alpha $. Finally we give some examples; in particular, we show that Slodowy slices, Nakajima quiver varieties, and hypertoric varieties are resolutions with conical slices.
WALLABY Early Science – IV. ASKAP H i imaging of the nearby galaxy IC 5201
Authors: Kleiner D , Koribalski B S , Serra P , Whiting M T , Westmeier T , Wong O I , Kamphuis P , Popping A , Bekiaris G , Elagali A , For B-Q , Lee-Waddell K , Madrid J P , Reynolds T N , Rhee J , Shao L , Staveley-Smith L , Wang J , Anderson C S , Collier J , Ord S M , Voronkov M A
Published: July 2019

We present a Wide-field ASKAP L-Band Legacy All-sky Blind surveY (WALLABY) study of the nearby (vsys  = 915 km s−1) spiral galaxy IC 5201 using the Australian Square Kilometre Array Pathfinder (ASKAP). IC 5201 is a blue, barred spiral galaxy that follows the known scaling relations between stellar mass, SFR, H i mass, and diameter. We create a four-beam mosaicked H i image cube from 175 h of observations made with a 12-antenna sub-array. The root mean square noise level of the cube is 1.7 mJy beam−1 per channel, equivalent to a column density of $N_{\rm H\, \small {I}}$  = 1.4 × 1020 cm−2 over 25 km s−1. We report nine extragalactic H i detections – five new H i detections including the first velocity measurements for two galaxies. These sources are IC 5201, three dwarf satellite galaxies, two galaxies, and a tidal feature belonging to the NGC 7232/3 triplet and two potential infalling galaxies to the triplet. There is evidence of a previous tidal interaction between IC 5201 and the irregular satellite AM 2220−460. A close fly-by is likely responsible for the asymmetric optical morphology of IC 5201 and warping its disc, resulting in the irregular morphology of AM 2220−460. We quantify the H i kinematics of IC 5201, presenting its rotation curve as well as showing that the warp starts at 14 kpc along the major axis, increasing as a function of radius with a maximum difference in position angle of 20°. There is no evidence of stripped H i, triggered or quenched star formation in the system as measured using DECam optical and GALEX UV photometry.
Inhibition of KIF20A by BKS0349 reduces endometriotic lesions in a xenograft mouse model
Authors: Ferrero H , Corachán A , Quiñonero A , Bougeret C , Pouletty P , Pellicer A , Domínguez F
Published: July 2019

Several studies have suggested a possible etiological association between ovarian endometriosis and ovarian cancer. Evidence has shown that KIF20A overexpression might confer a malignant phenotype to ovarian tumors by promoting proliferation and inhibiting apoptosis. However, no data about the role of KIF20A in endometriosis have been described. In this study, the human endometrium (n = 4) was transfected by mCherry adenovirus and intraperitoneally implanted in mice. Subsequently, mice were divided in three groups (n = 8/group) that were treated with Vehicle, BKS0349 (KIF20A-antagonist) or cabergoline (dopamine receptor agonist) for 21 days. mCherry-labeled endometriotic lesions were monitored over time using the IVIS Imaging System. Mice were sacrificed 72 h after the last administration; proliferation was evaluated by immunohistochemistry and apoptosis by TUNEL. CCND1 gene expression (G1 phase-related gene) was measured by qRT-PCR. A significant reduction in mCherry-fluorescent signal was observed in the BKS0349 group after treatment ended (D24) compared with D0 (P-value = 0.0313). Moreover, the mCherry signal on D24 showed a significant decrease in the BKS0349 group compared with controls (P-value = 0.0303), along with significant size reduction of endometriotic lesions observed in the BKS0349 group compared with control on D24 (P-value = 0.0006). Functional studies showed a significant reduction in proliferating cells in the BKS0349-treated group compared with controls (P-value = 0.0082). In addition, CCND1 expression was decreased in the BKS0349 group compared with control (P-value = 0.049) at D24 and a significant increase in apoptotic cells among endometriotic lesions in BKS0349-treated mice was observed compared with control (P-value = 0.0317). Based on these findings, we concluded that BKS0349 induces apoptosis and inhibits cell proliferation, reducing endometriotic lesion size and suggesting KIF20A inhibition by BKS0349 as a novel therapeutic treatment for endometriosis.
Ionic thermal up-diffusion in nanofluidic salinity-gradient energy harvesting
Authors: Long Rui , Kuang Zhengfei , Liu Zhichun , Liu Wei
Published: July 2019

Advances in nanofabrication and materials science give a boost to the research in nanofluidic energy harvesting. Contrary to previous efforts on isothermal conditions, here a study on asymmetric temperature dependence in nanofluidic power generation is conducted. Results are somewhat counterintuitive. A negative temperature difference can significantly improve the membrane potential due to the impact of ionic thermal up-diffusion that promotes the selectivity and suppresses the ion-concentration polarization, especially at the low-concentration side, which results in dramatically enhanced electric power. A positive temperature difference lowers the membrane potential due to the impact of ionic thermal down-diffusion, although it promotes the diffusion current induced by decreased electrical resistance. Originating from the compromise of the temperature-impacted membrane potential and diffusion current, a positive temperature difference enhances the power at low transmembrane-concentration intensities and hinders the power for high transmembrane-concentration intensities. Based on the system's temperature response, we have proposed a simple and efficient way to fabricate tunable ionic voltage sources and enhance salinity-gradient energy conversion based on small nanoscale biochannels and mimetic nanochannels. These findings reveal the importance of a long-overlooked element—temperature—in nanofluidic energy harvesting and provide insights for the optimization and fabrication of high-performance nanofluidic power devices.
Robot-Assisted Cortical Bone Trajectory Insertion of Pedicle Screws: 2-Dimensional Operative Video
Authors: Agyei Justice O , Khan Asham , Jowdy Patrick K , O’Connor Timothy E , Meyers Joshua E , Mullin Jeffrey P , Pollina John
Published: July 2019

Robot-assisted pedicle screw insertion has been slowly gaining popularity in the spine surgery community. In previous studies, robotics has been shown to increase accuracy and reduce complication rates compared to other navigation technologies, although those studies have been conducted using traditional trajectories for pedicle screw insertion. We present a surgical video in which a robotics system (Mazor X; Mazor Robotics Ltd, Caesarea, Israel) was used to create cortical bone trajectories for the insertion of the screws. The patient in this case is a 52-yr-old woman with severe L4-5 disc herniation requiring a transforaminal interbody fusion with the insertion of pedicle screws. The robotic system's scan-and-plan technique was utilized, in which an intraoperative computed tomography (CT) scan generates a real-time operative plan. Other techniques for inserting pedicle screws using cortical bone trajectories include CT navigation and fluoroscopic guidance. These techniques allow the surgeon to manually direct the screw under precise guidance in multiple planes, although the surgeon is still using all 6 degrees of freedom the human hand provides. With robotic guidance, a pilot hole is drilled, which eliminates 4 of 6 degrees of freedom, which can potentially reduce the risk of misplaced screws. To our knowledge, this is the first video demonstrating pedicle screw insertion through cortical bone trajectories using robotic guidance. Future studies are warranted to compare cortical bone trajectory insertion using different navigation techniques to determine the long-term efficacy of each technique.

The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary.
The Invariant Nature of a Morphological Character and Character State: Insights from Gene Regulatory Networks
Authors: Tarasov Sergei
Published: July 2019

What constitutes a discrete morphological character versus character state has been long discussed in the systematics literature but the consensus on this issue is still missing. Different methods of classifying organismal features into characters and character states (CCSs) can dramatically affect the results of phylogenetic analyses. Here, I show that, in the framework of Markov models, the modular structure of the gene regulatory network (GRN) underlying trait development, and the hierarchical nature of GRN evolution, essentially remove the distinction between morphological CCS, thus endowing the CCS with an invariant property with respect to each other. This property allows the states of one character to be represented as several individual characters and vice versa. In practice, this means that a phenotype can be encoded using a set of characters or just one complex character with numerous states. The representation of a phenotype using one complex character can be implemented in Markov models of trait evolution by properly structuring transition rate matrix.
Effects of distillers dried grains with solubles supplementation on yearling heifers grazing Northern Great Plains rangeland: impacts on subsequent feedlot performance and meat quality1
Authors: Larson Quynn P , Maddock Robert J , Neville Bryan W
Published: July 2019

Eighty-two yearling crossbred heifers (318.8 ± 1.03 kg) were utilized in a completely randomized design to evaluate the effects of distillers dried grains with solubles (DDGS) supplementation on animal performance, while grazing on rangeland of the Northern Great Plains, and subsequent feedlot performance, carcass characteristics, and meat quality traits. Treatments were: 1) 0% DDGS supplementation (CONT) and 2) 0.6% of body weight (BW) DDGS supplementation (SUP). Heifers received treatments for 70 d (6 June to 16 August) while grazing, and then were acclimated to and fed a common corn-based finishing diet for 109 d. Average daily gain (ADG) of SUP heifers was greater (P ≤ 0.01), resulting in heavier BW (P ≤ 0.03) following grazing compared with CONT heifers. Heifer performance, including ADG (1.91 ± 0.05 kg/d), gain to feed (G:F) (0.15 ± 0.003 kg), dry matter intake (DMI) (12.6 ± 0.20 kg), and final BW (572.4 ± 7.43 kg) were not different (P ≥ 0.13) during finishing. Hot carcass weight (335.7 ± 4.39 kg), Longissimus muscle area (81.30 ± 1.24 cm2), 12th rib fat thickness (1.24 ± 0.06 cm), and kidney, pelvic, heart fat (KPH) (1.85 ± 0.08%) were not different (P ≥ 0.47) between treatments. There were no differences (P ≥ 0.24) between treatments in yield grade (2.9 ± 0.10) or marbling (492 ± 22.3; Small00 = 400). Results from Warner–Bratzler shear force indicated that strip loin steaks from SUP heifers tended (P = 0.07) to have increased tenderness compared with strip loin steaks from CONT heifers (3.3 vs. 3.7 ± 0.12 kg, respectively). Inclusion of 0.6% BW supplementation during grazing increased (P = 0.01) strip loin steak muscle lightness (L*) compared with CONT steaks (46.5 vs. 45.5 ± 0.27, respectively). Strip loin steaks from heifers supplemented DDGS during grazing were perceived to be more tender by taste panelists (P = 0.02) than strip loin steaks from CONT heifers (5.9 vs. 5.5 ± 0.11; eight-point scale). Supplementation of DDGS during grazing improved ADG of yearling heifers with no effect on feedlot performance or carcass characteristics but did improve tenderness and steak sensory attributes.
Diel dynamics of dissolved organic matter and heterotrophic prokaryotes reveal enhanced growth at the ocean’s mesopelagic fish layer during daytime
Authors: Morán Xosé Anxelu G. , García Francisca C. , Røstad Anders , Silva Luis , Al-Otaibi Najwa , Irigoien Xabier , Calleja Maria L.
Published: July 2019

Contrary to epipelagic waters, where biogeochemical processes closely follow the light and dark periods, little is known about diel cycles in the ocean’s mesopelagic realm. Here, we monitored the dynamics of dissolved organic matter (DOM) and planktonic heterotrophic prokaryotes every 2 h for one day at 0 and 550 m (a depth occupied by vertically migrating fish during light hours) in oligotrophic waters of the central Red Sea. We additionally performed predator-free seawater incubations of samples collected from the same site both at midnight and at noon. Comparable in situ variability in microbial biomass and dissolved organic carbon concentration suggests a diel supply of fresh DOM in both layers. The presence of fish in the mesopelagic zone during daytime promoted a sustained, longer growth of larger prokaryotic cells. The specific growth rates were consistently higher in the noon experiments from both depths (surface: 0.34 vs. 0.18 d−1, mesopelagic: 0.16 vs. 0.09 d−1). Heterotrophic bacteria and archaea in the mesopelagic fish layer were also more efficient at converting DOM into new biomass. These results suggest that the ocean’s twilight zone receives a consistent diurnal supply of labile DOM from diel vertical migrating fishes, enabling an unexpectedly active community of heterotrophic prokaryotes.
uORFlight: a vehicle towards uORF-mediated translational regulation mechanisms in eukaryotes
Authors: Niu Ruixia , Zhou Yulu , Mou Rui , Tang Zhijuan , Wang Zhao , Zhou Guilong , Guo Sibin , Yuan Meng , Xu Guoyong
Published: July 2019

Upstream open reading frames (uORFs) are prevalent in eukaryotic mRNAs. They act as a translational control element for precisely tuning the expression of the downstream major open reading frame (mORF) with essential cellular functionalities. uORF variation has been clearly associated with several human diseases. In contrast, natural uORF variants in plants have not ever been identified or linked with any phenotypic changes. The paucity of such evidence encouraged us to generate this database-uORFlight (http://uorflight.whu.edu.cn). It facilitates the exploration of uORF variation among different splicing models of Arabidopsis and rice genes. Most importantly, users can evaluate uORF frequency among different accessions at the population scale and find out the causal single nucleotide polymorphism (SNP) or insertion/deletion (INDEL) which can be associated with phenotypic variation through database mining or simple experiments. Such information will help to make hypotheses of uORF function in plant development or adaption to changing environments on the basis of the cognate mORF function. This database also curates plant uORF relevant literature into distinct groups. To be broadly interesting, our database expands uORF annotation into more species of fungi (Botrytis cinerea), plant (Brassica napus, Glycine max, Gossypium raimondii, Medicago truncatula, Solanum lycopersicum, Solanum tuberosum, Triticum aestivum and Zea mays), metazoan (Caenorhabditis elegans and Drosophila melanogaster) and vertebrate (Homo sapiens, Mus musculus and Danio rerio). Therefore, uORFlight will light up the runway toward how uORF genetic variation determines phenotypic diversity and advance our understanding of translational control mechanisms.
Arbovirus Vectors of Epidemiological Concern in the Americas: A Scoping Review of Entomological Studies on Zika, Dengue and Chikungunya Virus Vectors
Authors: Jones Reilly , Kulkarni Manisha A. , Davidson Thomas M. V. ,   RADAM-LAC Research Team, Talbot Benoit
Published: July 2019

Background

Three arthorpod-borne viruses (arboviruses) causing human disease have been the focus of a large number of studies in the Americas since 2013 due to their global spread and epidemiological impacts: Zika, dengue, and chikungunya viruses. A large proportion of infections by these viruses are asymptomatic. However, all three viruses are associated with moderate to severe health consequences in a small proportion of cases. Two mosquito species,Aedes aegyptiandAedes albopictus, are among the world’s most prominent arboviral vectors, and are known primary vectors for all three viruses in the Americas.

Objectives

This review summarizes the state of the entomological literature surrounding the biology and ecology of vectors of Zika, dengue and chikungunya viruses and factors affecting virus transmission. The rationale of the review was to elucidate consensus and discord between studies, and guide future research based on identified knowledge gaps.

Results

A total of 196 studies were included in the scoping review after initial screening and subsequent exclusion of out-of-scope studies, secondary data publications, duplicate records, and studies unavailable in English language.

Key findings

Temperature and humidity have the strongest impact on mosquito distribution and dynamics, development of immatures and arborviral infection rates. Low socioeconomic status and related factors, including poor infrastructure, inconsistent access to water, and high household resident density, have been consistently associated with arbovirus vector occurrence. Effects of interspecific competition on arboviral vector species is currently poorly understood. Vector competence for Zika virus is well established forAe. aegyptiandAe. albopictus. Information on Zika virus vector transmission dynamics is sparse in contrast to the wealth of research available for dengue and chikungunya viruses.

Conclusions

Based on the internationally recognized urgency of Zika virus infection as a public health concern, further research on arbovirus vectors and transmission dynamics is of pressing need.
Foraging fidelity and individual specialisation in a temperate bat Myotis Nattereri
Authors: Mordue Simone , Mill Aileen , Shirley Mark , Aegerter James
Published: July 2019

Bat populations have declined globally over the last century largely due to anthropogenic change. Many temperate forest species of bat appear loyal to their foraging sites however, conservation of these sites rather than just habitat types is rarely considered and is essential to protect bat populations. It is not clear whether site fidelity in bats is species-specific or a more general trait or why it is exhibited but behaviour patterns could be important for conservation and management objectives. Foraging variation may occur due to ‘individual specialisation’, such that individuals differ significantly in their prey or habitat utilisation, independent of class-effects. If bats do exhibit individuality in their habitat choice, then protection of a mosaic of habitats rather than single preferred habitat per species may be critical to their conservation.

The goal here was to determine whether Natterer’s bats show fidelity in their foraging choices and whether they show individual specialisation in their foraging habits.

Thirty-four individual bats were tracked for at least one full night, from two different sites.

Site fidelity in Natterer’s was consistent across a range of intervals (months and years) despite contrasting seasonal contexts. Individuals repeatedly exploited specific foraging locations and showed individual specialisation in their habitat use which is consistent with the behaviour of a territorial species.

Studies designed to inform conservation and management of temperate bats should attempt to maximize the number of individuals from which movement data is sought, whilst ensuring that data represent a coherent and meaningful measure of behaviour such as a single full night. Bat conservation may need to shift from general descriptions of habitat preferences to considering individual specialisation in habitat use. Designing conservation strategies resilient to environmental change might then advocate protecting a mosaic of habitats to preserve the habitat specialisms of many individuals and enhance their productivity rather than advocating the preservation of a single preferred habitat only suited to a few individuals.
Perirhinal input to neocortical layer 1 controls learning
Authors: Doron Guy , Shin Jiyun N. , Takahashi Naoya , Bocklisch Christina , Skenderi Salina , Drüke Moritz , de Mont Lisa , Toumazo Maria , von Heimendahl Moritz , Brecht Michael , Naud Richard , Larkum Matthew E.
Published: July 2019

Signals sent back to the neocortex from the hippocampus control the long-term storage of memories in the neocortex1,2, but the cellular mechanisms underlying this process remain elusive. Here, we show that learning is controlled by specific medial-temporal input to neocortical layer 1. To show this we used direct cortical microstimulation detection task that allowed the precise region of learning to be examined and manipulated. Chemogenetically suppressing the last stage of the medial temporal loop, i.e. perirhinal cortex input to neocortical layer 1, profoundly disrupted early memory formation but had no effect on behavior in trained animals. The learning involved the emergence of a small population of layer 5 pyramidal neurons (~10%) with significantly increased firing involving high-frequency bursts of action potentials that were also blocked by suppression of perirhinal input. Moreover, we found that dendritic excitability was correspondingly enhanced in a similarly-sized population of pyramidal neurons and suppression of dendritic activity via optogenetic activation of dendrite-targeting inhibitory neurons also suppressed learning. Finally, single-cell stimulation of cortical layer 5 pyramidal neurons showed that burst but not regular firing retrieved previously learned behavior. We conclude that the medial temporal input to the neocortex controls learning through a process in L1 that elevates dendritic calcium and promotes burst firing.
The Kinesin-5 Tail Domain Directly Modulates the Mechanochemical Cycle of the Motor for Anti-Parallel Microtubule Sliding
Authors: Bodrug Tatyana , Wilson-Kubalek Elizabeth , Nithianantham Stanley , Thompson Alex F. , Alfieri April , Gaska Ignas , Major Jennifer , Debs Garret , Inagaki Sayaka , Gutierrez Pedro , Gheber Larissa , McKenney Richard , Sindelar Charles , Milligan Ronald , Stumpff Jason , Rosenfeld Steven , Forth Scott T. , Al-Bassam Jawdat
Published: July 2019

Kinesin-5 motors organize mitotic spindles by sliding apart anti-parallel microtubules. They are homotetramers composed of two antiparallel dimers placing orthogonal motor and tail domains at opposite ends of a bipolar minifilament. Here, we describe a regulatory mechanism, involving direct binding of the tail to motor domain and reveal its fundamental role in microtubule sliding motility. Biochemical analyses reveal that the tail down-regulates microtubule-activated ATP hydrolysis by specifically engaging the motor in the nucleotide-free or ADP-bound states. Cryo-EM structures reveal that the tail stabilizes a unique conformation of the motor N-terminal subdomain opening its active site. Full-length kinesin-5 motors undergo slow motility and cluster together along microtubules, while tail-deleted motors exhibit rapid motility without clustering along microtubules. The tail is critical for motors to zipper together two microtubules by generating substantial forces within sliding zones. The tail domain is essential for kinesin-5 mitotic spindle localization in vivo, which becomes severely reduced when the tail is deleted. Our studies suggest a revised microtubule-sliding model, in which tail domains directly engage motor domains at both ends of kinesin-5 homotetramers enhancing stability of the dual microtubule-bound states leading to slow motility yet high force production.
Celsr1a is essential for tissue homeostasis and onset of aging phenotypes in the zebrafish
Authors: Li Chunmei , Barton Carrie , Henke Katrin , Daane Jake , Caetano-Lopes Joana , Tanguay Robert , Harris Matthew P.
Published: July 2019

The use of experimental genetics has been invaluable in defining the complex mechanisms by which aging and longevity are regulated. Zebrafish, while a prominent model for understanding the genetic basis of vertebrate development, have not been used systematically to address questions of how and why we age. In a mutagenesis screen focusing on late developmental phenotypes, we identified a new mutant, fruehrentner, that displays typical signs of aging already at young adult stages. We find that the phenotype is due to loss-of-function in the non-classical cadherin EGF LAG seven-pass G-type receptor 1a (celsr1a). The premature aging phenotype is not associated with increased cellular senescence or decreased telomere length but is a result of a broad failure to maintain progenitor cell populations in tissues. Through the analysis of a knockin reporter line, we find that celsr1aGFP is expressed broadly in early development but becomes restricted during maturation. We show that celsr1a is essential for maintenance of stem cell progenitors and leads to shifts in cell fate determination. Although celsr1a has many signaling functions including establishment of polarity within tissues, we show that caloric restriction can ameliorate the effect of celsr1a on lifespan in part through compensatory upregulation of celsr1 paralogues. These data suggest that celsr1a function helps to mediate stem cell maintenance during maturation and homeostasis of tissues and thus regulates the onset or expressivity of aging phenotypes.
Signatures of relaxed selection in the CYP8B1 gene of birds and mammals
Authors: Shinde Sagar Sharad , Teekas Lokdeep , Sharma Sandhya , Vijay Nagarjun
Published: July 2019

The CYP8B1 gene is known to catalyse reactions that determine the ratio of primary bile salts and the loss of this gene has recently been linked to lack of cholic acid in the bile of naked-mole rats, elephants and manatees using forward genomics approaches. We screened the CYP8B1 gene sequence of more than 200 species and test for relaxation of selection along each terminal branch. The need for retaining a functional copy of the CYP8B1 gene is established by the presence of a conserved open reading frame across most species screened in this study. Interestingly, the dietary switch from bovid to cetacean species is accompanied by an exceptional ten amino-acid extension at the C-terminal end through a single base frame-shift deletion. We also verify that the coding frame disrupting mutations previously reported in the elephant are correct, are shared by extinct Elephantimorpha species and coincide with the dietary switch to herbivory. Relaxation of selection in the CYP8B1 gene of the wombat (Vombatus ursinus) also corresponds to drastic change in diet. In summary, our forward genomics based screen of bird and mammal species identifies recurrent changes in the selection landscape of the CYP8B1 gene concomitant with a change in dietary lipid content.
Chromosomal condensation leads to a preference for peripheral heterochromatin
Authors: MacPherson Quinn , Spakowitz Andrew J.
Published: July 2019

A layer of dense heterochromatin is found at the periphery of the nucleus. Because this peripheral heterochromatin functions as a repressive phase, mechanisms that relocate genes to the periphery play an important role in regulating transcription. Using Monte-Carlo simulations, we show that an interaction between chromatin and the nuclear boundary need not be specific to heterochromatin in order to preferentially locate heterochromatin to the nuclear periphery. This observation considerably broadens the class of possible interactions that result in peripheral positioning to include boundary interactions that either weakly attract all chromatin or strongly bind to a randomly chosen small subset of loci. The key distinguishing feature of heterochromatin is its high chromatin density with respect to euchromatin. In our model this densification is caused by HP1’s preferential binding to H3K9me3 marked histone tails. We conclude that factors that are themselves unrelated to the nuclear periphery can determine which genomic regions condense to form heterochromatin and thereby control which regions are relocated to the periphery.
Collagen-binding byDrosophilaSPARC is essential for survival and for collagen IV distribution and assembly into basement membranes
Authors: Duncan Sebastian , Delage Samuel , Chioran Alexa , Sirbu Olga , Brown Theodore J. , Ringuette Maurice J.
Published: July 2019

The assembly of basement membranes (BMs) into tissue-specific morphoregulatory structures requires non-core BM components. Work inDrosophilaindicates a principal role of collagen-binding matricellular glycoprotein SPARC (Secreted Protein, Acidic, Rich in Cysteine) in larval fat body BM assembly. We report that SPARC and collagen IV (Col(IV)) first colocalize in the trans-Golgi of hemocytes. Mutating the collagen-binding epitopes of SPARC leads to 2ndinstar larval lethality, indicating that SPARC binding to Col(IV) is essential for survival. Analysis of this mutant reveals increased Col(IV) puncta within adipocytes and intense perimeter Col(IV) staining surrounding the fat body as compared to wild-type larvae, reflecting a disruption in chaperone-like activity. In addition, Col(IV) in the wing imaginal disc was absent. Removal of the disulfide bridge in EF-hand2, which is known to enhance Col(IV) binding by SPARC, did not lead to larval lethality; however, a similar but less intense fat body phenotype was observed. Additionally, both SPARC mutants have altered fat body BM pore topography. Wing imaginal disc-derived SPARC did not localize within Col(IV)-rich matrices, indicating a distinct variant. Collectively, these data demonstrate the essential role of Col(IV) chaperone-like activity of SPARC toDrosophiladevelopment and indicate tissue-specific variants with differential functions.
The EO771 mammary cancer cell line displays a luminal B phenotype and it is sensitive to anti-estrogen treatments
Authors: Le Naour Augustin , Koffi Yvonne , Diab Mariane , Le Guennec Delphine , Rougé Stéphanie , Aldekwer Sahar , Goncalves-Mendes Nicolas , Talvas Jeremie , Farges Marie-Chantal , Caldefie-Chezet Florence , Vasson Marie-Paule , Rossary Adrien
Published: July 2019

Despite decades of therapeutic trials, detection, many drugs available and numerous studies on breast cancer, it remains the most deadly cancer in women. In order to choose the most appropriate treatment and to know the prognosis of the patients, the breast cancer is divided into different subtypes using a molecular classification. Thus, the need to discover new effective therapy is necessary, requiring to have models to test them. The EO771 (also named E0771 or EO 771) murine mammary cancer cell line is originally isolated from a spontaneous tumor in C57BL/6 mouse. Although frequently used, this cell line remains poorly characterized. Therefore, the EO771 phenotype was investigated. Transcriptomic and protein analysis allowed to classify the EO771 as luminal B subtype and more precisely estrogen receptor α negative, estrogen receptor β positive, progesterone receptor positive and ErbB2 positive. This phenotype was associated to a sensitivity to anti-estrogen treatments such as tamoxifen, 4-hydroxy-tamoxifen, endoxifen and fulvestrant.
Energy-dispersive Laue diffraction by means of a pnCCD detector coupled to a CsI(Tl) scintillator using ultra-hard X-ray synchrotron radiation
Authors: Shokr Mohammad , Tosson Amir , Abboud Ali , Algashi Alaa , Schlosser Dieter , Hartmann Robert , Klaus Manuela , Genzel Christoph , Strüder Lothar , Pietsch Ullrich
Published: July 2019

The lattice parameters and unit-cell orientation of an SrLaAlO4crystal have been determined by means of energy-dispersive X-ray Laue diffraction (EDLD) using a pnCCD detector coupled to a columnar structure CsI(Tl) scintillator in the energy range between 40 and 130 keV. By exploiting the high quantum efficiency (QE) achieved by this combined detection system for hard X-rays, a large number of Bragg reflections could be recorded by the relatively small detector area, allowing accurate and fast determination of the lattice parameters and the moduli of the structure factors. The experiment was performed on the energy-dispersive diffraction (EDDI) beamline at the BESSY II synchrotron using a pnCCD detector with 128 × 128 pixels. Since the energies and positions of the Laue peaks can be recorded simultaneously by the pnCCD system, the tetragonal structure of the investigated specimen was determined without any prior information. The unit-cell parameters and the angles between the lattice vectors were evaluated with an accuracy of better than 0.7%, while the structure-factor moduli of the reflections were determined with a mean deviation of 2.5% relative to the theoretical values.
A framework for tolerance design considering systematic and random uncertainties due to operating conditions
Authors: Khodaygan S.
Published: July 2019

Purpose

The purpose of this paper is to present a novel Kriging meta-model assisted method for multi-objective optimal tolerance design of the mechanical assemblies based on the operating conditions under both systematic and random uncertainties.

Design/methodology/approach

In the proposed method, the performance, the quality loss and the manufacturing cost issues are formulated as the main criteria in terms of systematic and random uncertainties. To investigate the mechanical assembly under the operating conditions, the behavior of the assembly can be simulated based on the finite element analysis (FEA). The objective functions in terms of uncertainties at the operating conditions can be modeled through the Kriging-based metamodeling based on the obtained results from the FEA simulations. Then, the optimal tolerance allocation procedure is formulated as a multi-objective optimization framework. For solving the multi conflicting objectives optimization problem, the multi-objective particle swarm optimization method is used. Then, a Shannon’s entropy-based TOPSIS is used for selection of the best tolerances from the optimal Pareto solutions.

Findings

The proposed method can be used for optimal tolerance design of mechanical assemblies in the operating conditions with including both random and systematic uncertainties. To reach an accurate model of the design function at the operating conditions, the Kriging meta-modeling is used. The efficiency of the proposed method by considering a case study is illustrated and the method is verified by comparison to a conventional tolerance allocation method. The obtained results show that using the proposed method can lead to the product with a more robust efficiency in the performance and a higher quality in comparing to the conventional results.

Research limitations/implications

The proposed method is limited to the dimensional tolerances of components with the normal distribution.

Practical implications

The proposed method is practically easy to be automated for computer-aided tolerance design in industrial applications.

Originality/value

In conventional approaches, regardless of systematic and random uncertainties due to operating conditions, tolerances are allocated based on the assembly conditions. As uncertainties can significantly affect the system’s performance at operating conditions, tolerance allocation without including these effects may be inefficient. This paper aims to fill this gap in the literature by considering both systematic and random uncertainties for multi-objective optimal tolerance design of mechanical assemblies under operating conditions.
Multi-objective optimal design of double-sided switched reluctance linear generator for wave power generation
Authors: Zhao Shuyan , Chen Hao , Nie Rui , Liu Jinfu
Published: July 2019

Purpose

This paper aims to propose a double-sided switched reluctance linxear generator (DSRLG) exclusively for wave power generation. The initial dimensions are given through design experience and principles. To ameliorate comprehensive performance of the DSRLG, the multi-objective optimization design is processed.

Design/methodology/approach

The multi-objective optimization design of the DSRLG is processed by adopting a modified entropy technique for order of preference by similarity to ideal solution (TOPSIS) algorithm. First, sensitivity analyzes on geometric parameters of the DSRLG are conducted to determine several pivotal geometric parameters as optimization variables. Then, the multi-objective optimization is conducted on the basis of initial dimensions. After determination of synthetical evaluation value of each structure parameter, the best dimension scheme of the DSRLG is concluded.

Findings

After verification by finite element method simulation and dynamic simulation, the final dimension scheme proves to perform better than the initial scheme. Finally, experiments are conducted to verify the accuracy of both the stable finite element DSRLG model and dynamic simulation system model so that the conclusion of this paper proves to be reliable and compelling.

Originality/value

This paper proposes an improved structure of the DSRLG, which is superior for wave power generation. Meanwhile, a novel modified entropy TOPSIS algorithm is applied to the field of electrical machine multi-objective optimal design for the first time.
Antecedents of graduate student satisfaction through e-portfolio: content analysis
Authors: Shea Timothy , Parayitam Satyanarayana
Published: July 2019

Purpose

Using content analysis on assessment of a student’s learning, the purpose of this paper is to investigate the effect of teaching on students through self-disclosure in E-portfolios. The antecedents of graduate student satisfaction are studied using a conceptual model.

Design/methodology/approach

The data from 50 E-portfolios from senior MBA students was analyzed following the steps outlined by Krippendorff (2004). A conceptual model was developed and tested using hierarchical regression. Teaching tools and delivery method by the professors were the moderators in the relationship between learning, professor dedication and teaching tools and student satisfaction.

Findings

The results suggest learning, professor dedication, course content, faculty engagement and teaching method are positively related to student satisfaction. Results also suggest that teaching tools moderate the relationship between learning and student satisfaction, and delivery method moderates the relationship between faculty engagement, professor dedication and student satisfaction.

Research limitations/implications

The present research is based on self-report documents from E-portfolios of MBA students from an accredited university in north-eastern part of Massachusetts. Since the authors used content analysis, the limitations of social desirability bias and common method bias are not limitations which are inherent in self-report structured instruments. The research has implications for the higher educational institutions and studies in the field of education.

Practical implications

In addition to the students and faculty in educational institutions, the present study contributes to literature on E-portfolios and also for Association to Advance Collegiate Schools of Business accreditations. The implications for both academicians and practitioners are discussed.

Social implications

The findings from the study help in creating a fruitful academic environment in organizations.

Originality/value

The study provides new insights into the effect of learning, teaching method, delivery method, professor dedication on student satisfaction.
Understanding the trajectory of the academic progress of international students in the UK
Authors: Adisa Toyin Ajibade , Baderin Mashood , Gbadamosi Gbolahan , Mordi Chima
Published: July 2019

Purpose

The UK is a popular educational hub for international students from different parts of the world. These students often face different transitional challenges, which have a significant impact on the success or failure of their studies. The purpose of this paper is to systematically investigate the issues and challenges confronting international students in the UK in their efforts to acquire academic knowledge and achieve personal development.

Design/methodology/approach

A total of 104 UK-based international students in five higher education institutes in London from 25 countries participated in this study. The study was undertaken qualitatively through 21 semi-structured and 13 focus group interviews.

Findings

The findings reveal that the process of transitional adjustment is affected by various issues, all of which determine the duration of the students’ involvement in each stage of the transitional process. International students in the UK experience language/accent-related difficulties; impaired communication; and a difficult adjustment to the British education system and culture.

Research limitations/implications

The extent to which the findings of this research can be generalised is constrained by the limited scope of the research.

Practical implications

In choosing to study in the UK, international students primarily seek to obtain a qualification, other life experiences, and cultural assimilation. The students’ parents, institutions and the UK authorities (such as the Department of Education) have an important role in ensuring that the students achieve success. While the roles of parents and the UK authorities are not the focus of this paper, their supportive roles certainly allow students to complete the different stages of the process of transitional adjustment quickly and smoothly.

Originality/value

The study offers valuable insight into understanding the challenges facing international students in acquiring knowledge in a foreign land. The paper contributes to the pedagogic literature on this topic by proposing a three-stage scaffolding model.
Addressing the undergraduate internship challenge in developing countries
Authors: Chand Vijaya Sherry , Deshmukh Ketan Satish
Published: July 2019

Purpose

The difficulties higher education institutions in developing countries face in finding adequate and relevant onsite student internship opportunities make a case for online internships. The purpose of this paper is to present an online internship model, developed over a two-year period, which challenged students to engage in learning-by-doing projects that addressed a key barrier in the implementation of ICT policies in public education, the paucity of audio-visual content in local languages.

Design/methodology/approach

The design of the model comprised the development of instructional videos by 340 interns, the evaluation of the videos by two interns and their testing by 31 interns through a field experiment using a between-subjects pre-test – post-test design in 54 schools. The process was repeated the following year with the field experiment replaced by the development of teaching manuals. The changes in reflective learning among 112 of the 119 interns who developed video content in this repeat round were assessed.

Findings

The field experiment found that the intern-developed videos improved Mathematics and Science scores among school students but not the attitudes to these subjects. Participation in online internships improved reflective learning.

Research limitations/implications

The evaluation of change in reflective learning is based on self-reported measures.

Practical implications

The online internship model presented in the paper can address concerns related to inadequate internship opportunities, while addressing gaps in public policy implementation by systems such as education, health and rural development.

Originality/value

The paper outlines the design of an online student internship model and a methodology for implementing it. The study indicates the feasibility of a low-cost, large-scale online model of internship.
An exploration of university student perceptions of discipline
Authors: Krskova Hana , Breyer Yvonne , Baumann Chris , Wood Leigh Norma
Published: July 2019

Purpose

The role of discipline in achieving higher academic and workplace performance is receiving increasing attention; however, research into student discipline has historically centred on schools. The purpose of this paper is to explore how university students from multiple faculties and at different stages of academic progression understand discipline in higher education, with the aim to investigate how graduates could become more disciplined and more work ready.

Design/methodology/approach

This study adopted a qualitative exploratory approach. Semi-structured interviews were conducted with university students and analysed using thematic analysis.

Findings

The students viewed discipline as internally driven as opposed to being enforced externally, which is often the case in schools. Five main themes were identified as discipline dimensions: “focus”, “intention”, “responsibility”, “structure” and “time” (F.I.R.S.T.).

Originality/value

A new concept of discipline is presented, underpinned by a conceptual framework comprised of self-determination, goal-setting, self-efficacy, self-regulation and time management principles. A “Threshold Concept of Discipline”, a hierarchical four-layered concept that develops over time for every individual with the ultimate level being “Creative Discipline”, is proposed. These findings illuminate learning strategies that higher education institutions can use to further enhance learning and increase the work readiness of their graduates. Such strategies can empower students who aspire to perform at a higher level and to become true professionals.