bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epaxial muscle function in trotting dogs
Authors: Ritter Dale A. , Nassar Peter N. , Fife Mathew , Carrier David R. 
Published: April 2021

SUMMARY
One of the features that distinguish mammals from other groups of terrestrial vertebrates is the structure and relative size of their epaxial muscles. Yet we have only a superficial understanding of the role these muscles play in locomotion. To address their locomotor function, we recorded the electrical activity of the iliocostalis, longissimus dorsi and multifidus muscles of trotting dogs. Activity was monitored at both lumbar and thoracic sites. To develop and evaluate hypotheses of epaxial muscle function, we quantified footfall patterns and sagittal trunk kinematics from high-speed videos, and the magnitude and orientation of ground reaction forces from force-plate recordings. All three epaxial muscles tended to exhibit a double-bursting (biphasic) activity pattern, with the exception of the iliocostalis muscle at the thoracic site (which was uniphasic). In general, a large burst of activity in each muscle occurred during the second half of the support phase of the ipsilateral hindlimb, and was active for an average of 30% of the locomotor cycle. A smaller burst of activity occurred during the second half of the support phase of the contralateral hindlimb, and was active for an average of 15% of the locomotor cycle. Analysis of ground reaction forces and sagittal trunk kinematics led us to the hypothesis that the epaxial muscles do not directly stabilize the trunk against the vertical and horizontal components of the ground reaction force. Instead, the epaxial muscles appear to counteract the tendency of the trunk to rebound (flex) in the sagittal plane during the latter half of the support phase. This hypothesis of epaxial muscle function was supported by loading experiments performed on the longissimus dorsi muscle in the lumbar region.
Characterization of transepithelial potential oscillations in theDrosophilaMalpighian tubule
Authors: Blumenthal Edward M. 
Published: April 2021

SUMMARYThe Malpighian tubule of Drosophila melanogaster is a useful model system for studying the regulation of epithelial ion transport. In acutely isolated tubules, the transepithelial potential (TEP) undergoes large oscillations in amplitude with a period of approximately 30s. The TEP oscillations are diminished by reductions in the peritubular chloride concentration in a manner consistent with their being caused by fluctuations in chloride conductance. The oscillations are eliminated by pretreating tubules with the calcium chelator BAPTA-AM, although removal of peritubular calcium has no effect, suggesting that the oscillations are a result of either the release of calcium from intracellular stores or the entry of calcium from the tubule lumen. Transcripts encoding two calcium-release channels, the ryanodine receptor and the inositol trisphosphate receptor, are detectable in the tubule by reverse transcription–polymerase chain reaction. To identify the cell type responsible for the oscillations, tubules were treated with diuretic hormones known to alter calcium levels in each of the two cell types. Leucokinin-IV, which increases calcium levels in the stellate cells, suppressed the oscillations, whereas cardioacceleratory peptide 2b (CAP2b), which increases calcium levels in the principal cells, had no effect. These data are consistent with a model in which rhythmic changes in transepithelial chloride conductance, regulated by intracellular calcium levels in the stellate cells, cause the TEP oscillations.
The generalization of an olfactory-based conditioned response reveals unique but overlapping odour representations in the moth Manduca sexta
Authors: Daly Kevin C. , Chandra Sathees , Durtschi Michelle L. , Smith Brian H. 
Published: April 2021

SUMMARY
Most highly derived olfactory systems, such as the insect antennal lobe, discriminate among a wide array of monomolecular odourants and blends of odourants. Given the relatively limited number of neurons used to code these odours, this ability implies that neural representations for odours overlap in a cross-fiber coding scheme. Here we use the generalization of a conditioned feeding response in the sphinx moth, Manduca sexta, to quantify three geometry-based dimensions of odour space in which monomolecular odours may be assessed. In a series of experiments we show that generalization of a conditioned response from one monomolecular odour to another is a function of differences in length and shape of the carbon chain as well as the functional group on the molecule. When moths were conditioned to 2-hexanone or 1-decanol and tested with a number of alcohols and ketones, we found that the generalization of the conditioned response decreased as a function of the chain length and functional group. In contrast, when conditioned to 1-hexanol, moths failed to distinguish alcohols from ketones of the same chain length. In all of these cases, chain length did not interact with functional group, thus indicating the independence of these dimensions. Differential conditioning of alcohols and of alcohols and ketones revealed interaction of excitatory and inhibitory generalization gradients within an odour ‘dimension’. When odourants were sufficiently distinct, the peak of the generalization gradient was shifted away from the conditioning odour and in an opposite direction from the unreinforced odour. Altogether, these data substantiate the claim that these molecular characteristics are relevant coding dimensions in the moth olfactory system. These data are consistent with a cross-fiber coding scheme in which odours are coded by spatio–temporally overlapping sets of neurons, both in the periphery and in the antennal lobes.
Running in the surf: hydrodynamics of the shore crabGrapsus tenuicrustatus
Authors: Martinez Marlene M. 
Published: April 2021

SUMMARYWhen locomoting in water, animals experience hydrodynamic forces due to ambient water motion and their own motion through the water. Because an aquatic pedestrian must maintain contact with the substratum to locomote, hydrodynamic forces which can dislodge an animal have the capacity to constrain the postures, gaits and speeds an animal can use. This study measured hydrodynamic forces on the amphibious shore crab Grapsus tenuicrustatus in aquatic and terrestrial postures. The crabs’ locomotory speeds and ambient water velocities in their habitat were considered in predicting the conditions under which a crab is likely to overturn or wash away. A non-moving crab can withstand 200% faster flow in the aquatic posture than in the terrestrial posture. A crab using the terrestrial posture while locomoting through still water experiences 132% greater drag and 17% greater acceleration reaction forces than it does in the aquatic posture. Due to the lower hydrodynamic forces in the aquatic posture, a crab could locomote up to 50% more quickly or through a faster water flow environment than it could in the terrestrial posture. In faster flow environments like wave-swept rocky shores, a crab in either posture would have to actively grasp the substratum to keep from being dislodged, preventing it from using a punting gait. In slower flow environments, animals can locomote faster and take advantage of different gaits that are not available to them in faster flow environments.
Spread of synaptic potentials through electrical synapses in Retzius neurones of the leech
Authors: De-Miguel Francisco F. , Vargas-Caballero Mariana , García-Pérez Elizabeth 
Published: April 2021

SUMMARYWe studied the spread of excitatory postsynaptic potentials (EPSPs) through electrical synapses in Retzius neurones of the leech Haementeria officinalis. The pair of Retzius neurones in each ganglion is coupled by a non-rectifying electrical synapse. Both neurones displayed synchronous EPSPs of varying amplitudes and rise times. The kinetics of synchronous EPSPs was similar in 79 % of the EPSP pairs. In the remaining 21 %, one EPSP was smaller and slower than the other, suggesting its passive spread from the other neurone. The proportion of these events increased to 75 % in the presence of Mg2+ in the bathing fluid. This spread of EPSPs from one neurone to another was tested by producing artificial EPSPs by current injection into the soma of one Retzius neurone. The artificial EPSPs were smaller and arrived more slowly at the soma of the coupled neurone. The coupling ratios for the EPSPs were proportional to the coupling ratio for long steady-state pulses in different neuronal pairs. Our results showed that EPSPs spread from one Retzius neurone to the other and support the idea that EPSP spread between electrically coupled neurones may contribute to the integration processes of neurones.
Speeds and wingbeat frequencies of migrating birds compared with calculated benchmarks
Authors: Pennycuick C. J. 
Published: April 2021

SUMMARYSixteen species of birds passing Falsterbo in southwest Sweden during the autumn migration season were observed using short-range optical methods. Air speeds and wingbeat frequencies were measured, reduced to sea level, and compared with benchmark values computed by Flight.bas, a published flight performance program based on flight mechanics. The benchmark for air speed was the calculated sea-level value of the minimum power speed (Vmp). The mean speeds of three raptor species that flew by flap-gliding were below Vmp, apparently because the flap-glide cycle involved slowing down below Vmp when gliding and accelerating back up to Vmp when flapping. The mean speeds of 11 species that flew by continuous flapping were between 0.82Vmp and 1.27Vmp. Two passerine species that flew by bounding had mean speeds of 1.70Vmp and 1.96Vmp, but these high mean speeds reflected their ability to fly faster against head winds. These results do not support predictions from optimal migration theory, which suggest that migrating birds ‘should’ fly faster, relative to Vmp. However, observations were restricted for technical reasons to birds flying below 200 m and may not represent birds that were seriously committed to long-distance migration.The benchmark wingbeat frequency (fref) was derived from dimensional reasoning, not from statistical analysis of observations. Observed wingbeat frequencies ranged from 0.81fref to 1.05fref, except in the two bounding species, whose wingbeat frequencies appeared anomalously high. However, the mechanics of bounding with a power fraction q imply that gravity during the flapping phase is increased by a factor 1/q, and when the value of gravity was so adjusted in the expression for fref, the wingbeat frequencies of the two bounding species were predicted correctly as a function of the power fraction. In small birds with more muscle power than is required to fly at speeds near Vmp, bounding is an effective method of adjusting the specific work in the muscle fibres, allowing conversion efficiency to be maximised over a wide range of speeds.
Sodium and chloride regulation in freshwater and osmoconforming larvae ofCulexmosquitoes
Authors: Patrick Marjorie L. , Gonzalez Richard J. , Bradley Timothy J. 
Published: April 2021

SUMMARYIn this study, we examined aspects of Na+ and Cl– regulation in mosquito larvae of the genus Culex, a group that includes species that tolerate high salinity as well as other forms that are restricted to fresh water. When the euryhaline osmoconformer C. tarsalis was acutely transferred from 30 % to 50 % sea water, the patterns of hemolymph Na+ and Cl– regulation were similar. The underlying regulatory mechanisms for these two ions have very different characteristics. In C. tarsalis, Na+ efflux was significantly elevated compared with the rates measured in the freshwater-restricted C. quinquefasciatus, while Cl– influx was relatively lower. The modulation of Na+ efflux and Cl– influx allowed C. tarsalis to avoid a potential salt load and ionic disturbance in the hemolymph during an acute increase in salinity. The observed adjustment of NaCl regulation departs from that determined for other euryhaline organisms and is integral to the osmoconforming response. At the other extreme of the salinity spectrum, we observed that C. tarsalis faces difficulties in ion regulation in habitats with low NaCl levels because of its inability to reduce ion efflux and adjust ion absorption rates to maintain hemolymph ion balance. In contrast, C. quinquefasciatus exhibited a reduced ion efflux and the ability to upregulate Na+ uptake, traits necessary to extend its lower salinity limit.
Cellular mechanisms underlying temperature-induced bleaching in the tropical sea anemone Aiptasia pulchella
Authors: Sawyer Sara J. , Muscatine Leonard 
Published: April 2021

SUMMARY
Temperature-induced bleaching in symbiotic cnidarians is a result of the detachment and loss of host cells containing symbiotic algae. We tested the hypothesis that host cell detachment is evoked through a membrane thermotropic event causing an increase in intracellular calcium concentration, [Ca2+]i, which could then cause collapse of the cytoskeleton and perturb cell adhesion. Electron paramagnetic resonance measurements of plasma membranes from the tropical sea anemone Aiptasia pulchella and the Hawaiian coral Pocillopora damicornis labeled with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) revealed no membrane thermotropic event. In addition, intracellular imaging using Fura-2AM as well as labeling anemones with 45Ca revealed no significant change in [Ca2+]i. However, bleaching could be evoked at ambient temperature with 25 mmol l–1 caffeine without affecting [Ca2+]i. [Ca2+]i could be altered with ionomycin in isolated host cells, but ionomycin could not induce bleaching in A. pulchella. As caffeine can affect levels of intracellular protein phosphorylation, the ability of other agents that alter intracellular levels of protein phosphorylation to evoke bleaching was investigated. The protein phosphatase inhibitor vanadate could induce bleaching in A. pulchella. Two-dimensional gels of 32P-labeled proteins from cold-shocked, caffeine-treated and control anemones show that both temperature shock and caffeine alter the array of phosphorylated host soluble proteins. We conclude that cnidarian bleaching is linked to a temperature-induced alteration in protein phosphorylation.
Alternative splicing, muscle contraction and intraspecific variation: associations between troponin T transcripts, Ca2+ sensitivity and the force and power output of dragonfly flight muscles during oscillatory contraction
Authors: Marden James H. , Fitzhugh Gail H. , Girgenrath Mahasweta , Wolf Melisande R. , Girgenrath Stefan 
Published: April 2021

SUMMARYThe flight muscles of Libellula pulchella dragonflies contain a mixture of six alternatively spliced transcripts of a single troponin T (TnT) gene. Here, we examine how intraspecific variation in the relative abundance of different TnT transcripts affects the Ca2+ sensitivity of skinned muscle fibers and the performance of intact muscles during work-loop contraction regimes that approximate in vivo conditions during flight. The relative abundance of one TnT transcript, or the pooled relative abundance of two TnT transcripts, showed a positive correlation with a 10-fold range of variation in Ca2+ sensitivity of skinned fibers (r2=0.77, P&lt;0.0001) and a threefold range in peak specific force (r2=0.74, P&lt;0.0001), specific work per cycle (r2=0.54; P&lt;0.0001) and maximum specific power output (r2=0.48, P=0.0005) of intact muscle. Using these results to reanalyze previously published data for wing kinematics during free flight, we show that the relative abundances of these particular transcripts are also positively correlated with wingbeat frequency and amplitude. TnT variation alone may be responsible for these effects, or TnT variation may be a marker for changes in a suite of co-regulated molecules. Dragonflies from two ponds separated by 16 km differed significantly in both TnT transcript composition and muscle contractile performance, and within each population there are two distinct morphs that showed different maturational trajectories of TnT transcript composition and muscle contractility. Thus, there is broad intraspecific variability and a high degree of population structure for contractile performance phenotypes, TnT ribotypes and ontogenetic patterns involving these traits that affect locomotor performance.
Data Management Plans in Horizon 2020: what beneficiaries think and what we can learn from their experience
Authors: Spichtinger Daniel 
Published: April 2021

Background: Data Management Plans (DMPs) are at the heart of many research funder requirements for data management and open data, including the EU’s Framework Programme for Research and Innovation, Horizon 2020. This article provides a summary of the findings of the DMP Use Case study, conducted as part of OpenAIRE Advance. Methods: As part of the study we created a vetted collection of over 800 Horizon 2020 DMPs. Primarily, however, we report the results of qualitative interviews and a quantitative survey on the experience of Horizon 2020 projects with DMPs. Results & Conclusions: We find that a significant number of projects had to develop a DMP for the first time in the context of Horizon 2020, which points to the importance of funder requirements in spreading good data management practices. In total, 82% of survey respondents found DMPs useful or partially useful, beyond them being “just” an European Commission (EC) requirement. DMPs are most prominently developed within a project’s Management Work Package. Templates were considered important, with 40% of respondents using the EC/European Research Council template. However, some argue for a more tailor-made approach. The most frequent source for support with DMPs were other project partners, but many beneficiaries did not receive any support at all. A number of survey respondents and interviewees therefore ask for a dedicated contact point at the EC, which could take the form of an EC Data Management Helpdesk, akin to the IP helpdesk. If DMPs are published, they are most often made available on the project website, which, however, is often taken offline after the project ends. There is therefore a need to further raise awareness on the importance of using repositories to ensure preservation and curation of DMPs. The study identifies IP and licensing arrangements for DMPs as promising areas for further research.
Efficient spontaneous emission by metal-dielectric antennas; antenna Purcell factor explained
Authors: Hooten Sean , Andrade Nicolas M. , Wu Ming C. , Yablonovitch Eli 
Published: April 2021

The rate of spontaneous emission from an optical emitter can be greatly enhanced using a metallic optical antenna at the penalty of efficiency. In this paper we propose a metal-dielectric antenna that eliminates the tradeoff between spontaneous emission enhancement and radiative efficiency by using nanoscopic dielectric structures at the antenna tips. This tradeoff occurs due to Ohmic loss and is further exacerbated by electron surface collisions. We find that our metal-dielectric antenna can enhance spontaneous emission by a factor 5 × 105 with efficiency = 70%, greatly exceeding the radiative efficiency of a purely metallic antenna with similar enhancement. Moreover, the metal-dielectric antenna design strategy is naturally amenable to short-distance optical communications applications. We go on to discuss the Purcell effect within the context of antenna enhancement. Metallic optical antennas are best analyzed with conventional antenna circuit models, but if the Purcell enhancement were to be employed, we provide the effective mode volume, Veff = (3/4π2)2 d2λ(λ/l)5, that would be needed.
Broadband chiral silicon photonic circuits based on fork-type inversely tapered nanowire waveguides
Authors: Fang Liang , Wang Jian 
Published: April 2021

Optical spin or circular polarization provides a new degree of freedom to control light–matter interaction in the fundamentals and applications of light. To broaden the bandwidth of chiral (spin-controlled) coupling in photonic integrated circuits, we propose fork-type inversely tapered nanowire waveguides to compensate for the out-of-step phase evolution of adiabatic coupling between

T
E

0

and

T
M

0

(

T
E

1

) modes excited from the

x

- and

y

-polarization components of spin polarized light in free space, respectively. We design and simulate two kinds of devices based on air and

S
i

3

N

4

up-claddings to show the feasibility of broadening the bandwidth of chiral silicon photonic circuits by using fork-type inverse tapers. Numerical results show that the bandwidth can approach 70 nm under high directionality of above 0.90. This broadband chiral coupling via the new phase synchronizing technique with fork-type inverse tapers may pave the way to develop on-chip spin photonics or polarization-based photonic integrated devices.
Association between in-stent neointimal characteristics and native coronary artery disease progression
Authors: Jung Hae Won , Lim Chewan , Bae Han Joon , Lee Jung-Hee , Lee Yong-Joon , Kim Jung-Sun , Lee Seung-Jun , Hong Sung-Jin , Ahn Chul-Min , Kim Byeong-Keuk , Ko Young-Guk , Choi Donghoon , Hong Myeong-Ki , Jang Yangsoo 
Published: April 2021

Background and aims
The prognosis of stented lesions differs according to in-stent neointimal characteristics on optical coherence tomography (OCT). In particular, patients who show in-stent heterogeneous neointima are associated with a higher incidence of target lesion revascularization (TLR) compared with those who show in-stent non-heterogeneous neointima. However, the relationship between in-stent neointimal characteristics and native coronary atherosclerosis progression has not been clearly elucidated. The study aimed to investigate the relationship between in-stent neointimal characteristics and progression of native atherosclerosis.

Methods
The neointimal characteristics of 377 patients with 377 drug-eluting stents (DESs) were quantitatively and qualitatively assessed using OCT. The OCT-based neointima was categorized as homogeneous (n = 207), heterogeneous (n = 93), and layered (n = 77). The relationship of non-target lesion revascularization (non-TLR) with neointimal characteristics was evaluated after OCT examination of the stents.

Results
After a median follow-up duration of 40.0 months, patients with heterogeneous neointima showed significantly higher non-TLR rates than those with homogeneous neointima and tended to have higher non-TLR rates than those with layered neointima (heterogeneous vs. homogeneous:14.0% vs. 8.7%, p = 0.046; heterogeneous vs. layered neointima:14.0% vs. 7.8%, p = 0.152). Multivariate analysis showed that the independent determinants for non-TLR were heterogeneous neointima (HR: 2.237, 95% CI: 1.023–4.890, p = 0.044) and chronic kidney disease (hazard ratio [HR]: 8.730, 95% CI: 2.175–35.036, p = 0.002).

Conclusions
The heterogeneous neointima in DES-treated lesions was associated with a higher incidence of non-TLR and target lesion failure. This finding suggests that the neointimal pattern may reflect the progression of the native lesion.