The basic helix–loop–helix transcription factor
Twist1 plays an essential role in mesenchymal cell populations during embryonic development and in pathological disease. Remodeling of the cardiac ...outflow tract (OFT) into the functionally separate aortic arch and pulmonary trunk is dependent upon the dynamic, coordinated contribution of multiple mesenchymal cell populations. Here, we report that
Twist1
−/−
mice exhibit OFTs that contain amorphic cellular nodules within their OFT endocardial cushions. The nodular mesenchyme expresses the related bHLH factors
Hand1 and
Hand2, but reduced levels of the normal cushion marker Periostin. Lineage mapping confirms that nodule cells are exclusively of cardiac neural crest origin (cNCC), and are not ectopic cardiomyocytes or smooth muscle cells. These studies also reveal a delay in cNCC colonization of the OFT cushions. Furthermore, these mapping studies uncover nodules in the pharyngeal arches, and identify
Twist1
−/−
neural crest cell defects within the dorsal neural tube, which exhibits an expanded domain of
Wnt1-Cre-lineage marked cells. Together, these data support a model where
Twist1 is required both for proper cNCC delamination, and for emigration from the dorsal neural tube and along cNCC migration pathways. Within the
Twist1
−/− neural crest cell populations that do emigrate to the OFT, a
Hand-expressing subpopulation displays defective maturation, tracking, and, presumably, cell–cell adhesion, further compromising cNCC morphogenesis.
As evidence mounted that existing prevention methods would be insufficient to end the COVID-19 pandemic, it became clear that vaccines would be critical to achieve and maintain reduced rates of ...infection. However, vaccine-hesitant sentiments have become widespread, particularly in populations with lower scientific literacy. The non-STEM major (called non-major) college students represent one such population who rely on one or more science classes to develop their scientific literacy and thus, become candidates of interest for the success of the COVID-19 vaccine campaign. As these students have fewer opportunities to learn how to identify reputable scientific sources or judge the validity of novel scientific findings, it is particularly important that these skills are included in the science courses offered to non-majors. Two concurrent non-major biology courses (
= 98) at the University of Alabama at Birmingham in Spring 2021 completed Likert questionnaires with open-ended questions prior to and after an expert-led Vaccine Awareness educational intervention addressing vaccine-related concerns. In the module, experts gave presentations about COVID-19 related to microbiology, epidemiological factors, and professional experiences relating to COVID-19. Ten students agreed to participate in post-semester one-on-one interviews. Student interviews revealed that students perceived guest lecturers as providing more information and assurance. Questionnaire data showed an increase in student willingness to accept a COVID-19 vaccine as well as increased student perception of the COVID-19 vaccines as both safe and effective (Wilcoxon Rank Sum Test,
< 0.05). However, the questionnaire data revealed 10 of 98 students remained vaccine-resistant, and these students expressed insufficient research and side effects as leading vaccination concerns. Overall, we show expert-led modules can be effective in increasing non-majors willingness to accept COVID-19 vaccines. Future research should explore the experiences of non-majors and guest lectures, particularly as they relate to vaccination and vaccine concerns.
Valli M, Barnes AM, Gallanti A, Cabral WA, Viglio S, Weis MA, Makareeva E, Eyre D, Leikin S, Antoniazzi F, Marini JC, Mottes M. Deficiency of CRTAP in non‐lethal recessive osteogenesis imperfecta ...reduces collagen deposition into matrix.
Deficiency of any component of the ER‐resident collagen prolyl 3‐hydroxylation complex causes recessive osteogenesis imperfecta (OI). The complex modifies the α1(I)Pro986 residue and contains cartilage‐associated protein (CRTAP), prolyl 3‐hydroxylase 1 (P3H1) and cyclophilin B (CyPB). Fibroblasts normally secrete about 10% of CRTAP. Most CRTAP mutations cause a null allele and lethal type VII OI. We identified a 7‐year‐old Egyptian boy with non‐lethal type VII OI and investigated the effects of his null CRTAP mutation on collagen biochemistry, the prolyl 3‐hydroxylation complex, and collagen in extracellular matrix. The proband is homozygous for an insertion/deletion in CRTAP (c.118_133del16insTACCC). His dermal fibroblasts synthesize fully overmodified type I collagen, and 3‐hydroxylate only 5% of α1(I)Pro986. CRTAP transcripts are 10% of control. CRTAP protein is absent from proband cells, with residual P3H1 and normal CyPB levels. Dermal collagen fibril diameters are significantly increased. By immunofluorescence of long‐term cultures, we identified a severe deficiency (10–15% of control) of collagen deposited in extracellular matrix, with disorganization of the minimal fibrillar network. Quantitative pulse‐chase experiments corroborate deficiency of matrix deposition, rather than increased matrix turnover. We conclude that defects of extracellular matrix, as well as intracellular defects in collagen modification, contribute to the pathology of type VII OI.
Tactics of resource use for reproduction are an important feature of life-history strategies. A distinction is made between ‘capital’ breeders, which finance reproduction using stored energy, and ...‘income’ breeders, which pay for reproduction using concurrent energy intake. In reality, vertebrates use a continuum of capital-to-income tactics, and, for many species, the allocation of capital towards reproduction is a plastic trait. Here, we review how trophic interactions and the timing of life-history events are influenced by tactics of resource use in birds and mammals. We first examine how plasticity in the allocation of capital towards reproduction is linked to phenological flexibility via interactions between endocrine/neuroendocrine control systems and the sensory circuits that detect changes in endogenous state, and environmental cues. We then describe the ecological drivers of reproductive timing in species that vary in the degree to which they finance reproduction using capital. Capital can be used either as a mechanism to facilitate temporal synchrony between energy supply and demand or as a means of lessening the need for synchrony. Within many species, an individual's ability to cope with environmental change may be more tightly linked to plasticity in resource allocation than to absolute position on the capital-to-income breeder continuum.
This article is part of the themed issue ‘Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals’.
The sensitivity of cadmium stannate (CTO) performance to both sputtering and annealing conditions was investigated. Films treated by the standard proximity anneal in contact with a CdS film displayed ...an electrical resistivity of ~2.2×10−4Ωcm, high mobility (~57cm2/Vs), and >90% transmission throughout the near infrared (λ≤1350nm). Film properties were insensitive to annealing temperature and sputtering ambient when O2 was present during deposition. Next, we demonstrated process modifications to the proximity anneal. CTO and CTO/CdS bilayer films were annealed either uncovered or covered with a bare glass plate. CTO/CdS bilayers annealed in the covered configuration had comparable or superior conductivity to the proximity anneal, with optimal performance achieved with 10nm of CdS. The resistivity of uncovered films and films produced without CdS was insensitive to CdS thickness (~3×10−4Ωcm), and displayed higher mobility and improved transparency, particularly in the near infrared. The electrical properties were well correlated with X-ray diffraction measurements of film crystallinity and purity. These high-conductivity films are promising for photovoltaic applications, transmitting 92–95% of solar radiation >1eV.
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•Film properties are insensitive to sputtering ambient for Ar/O2 with ≤80% Ar.•CTO/CdS bilayers produce films with superior performance to the proximity anneal.•Optimized CTO films have resistivity <2×10−4Ωcm and transmit 93% of AM1.5>1eV.•Films without CdS have competitive conductivity, improved transparency in near-IR.
Morphological and seismic data from a submarine landslide complex east of New Zealand indicate flow‐like deformation within gas hydrate‐bearing sediment. This “creeping” deformation occurs ...immediately downslope of where the base of gas hydrate stability reaches the seafloor, suggesting involvement of gas hydrates. We present evidence that, contrary to conventional views, gas hydrates can directly destabilize the seafloor. Three mechanisms could explain how the shallow gas hydrate system could control these landslides. (1) Gas hydrate dissociation could result in excess pore pressure within the upper reaches of the landslide. (2) Overpressure below low‐permeability gas hydrate‐bearing sediments could cause hydrofracturing in the gas hydrate zone valving excess pore pressure into the landslide body. (3) Gas hydrate‐bearing sediment could exhibit time‐dependent plastic deformation enabling glacial‐style deformation. We favor the final hypothesis that the landslides are actually creeping seafloor glaciers. The viability of rheologically controlled deformation of a hydrate sediment mix is supported by recent laboratory observations of time‐dependent deformation behavior of gas hydrate‐bearing sands. The controlling hydrate is likely to be strongly dependent on formation controls and intersediment hydrate morphology. Our results constitute a paradigm shift for evaluating the effect of gas hydrates on seafloor strength which, given the widespread occurrence of gas hydrates in the submarine environment, may require a reevaluation of slope stability following future climate‐forced variation in bottom‐water temperature.
Key Points
Low‐velocity active landslides are proposed to occur on the seafloor
Gas hydrates provide a perturbation mechanism for ongoing landslide mobility
We propose an active, mixed hydrate‐sediment seafloor glacier
The CERN Large Hadron Collider LHC is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams coming from the injector chain. Operation with high intensity beams for many hours ...can lead to significant beam induced heating of the ferrite yokes of the MKIs. When the ferrite exceeds the Curie temperature of 125°C it loses its magnetic properties, preventing further injection until the ferrite cools down, potentially causing a delay of several hours. Hence important upgrades of the beam-screen were implemented after Run 1 of LHC. However, the High-Luminosity (HL) LHC will be operated with significantly higher intensity beams and hence additional measures are required to limit the ferrite temperature. These magnets operate under ultra-high vacuum conditions: convection is negligible and, as a result of low emissivity of the inside of the vacuum tanks, thermal radiation is limited. A detailed study of the thermal behaviour of these magnets is reported and compared with measurements. In addition several options to improve cooling of the ferrites are presented and analysed.
According to Conway's view, Autobiographical memory (AM) construction is accompanied by control processes. These processes range from filtering out relevant memories according to the current context, ...to generating or elaborating appropriate retrieval cues. These processes can be conceptualised as metacognition, the ability to control and monitor cognitive processes. Experimentally, little has been carried out to support the idea that metacognition is involved in AM. To assess this, we designed a task, the Feeling of Retrieval. Participants had to predict whether cue words would facilitate AM access (i.e., fluent access cues) or not (i.e., limited access cues) in a limited time (either 1 (Exp. 2) or 2 (Exp. 1) s). Later, they retrieved memories in response to both types of cues. Results show that cues judged as fluent access led to better AM generation, as illustrated by AM retrieval latency and a subjective measure of the ease with which the AMs were retrieved. These rapid predictions may rely on epistemic feelings and / or other mnemonic cues such as a partial retrieval of information. This metacognitive access to the earliest stages of AM retrieval illustrates the ability to monitor AM processes as proposed by Conway (2005).According to Conway's view, Autobiographical memory (AM) construction is accompanied by control processes. These processes range from filtering out relevant memories according to the current context, to generating or elaborating appropriate retrieval cues. These processes can be conceptualised as metacognition, the ability to control and monitor cognitive processes. Experimentally, little has been carried out to support the idea that metacognition is involved in AM. To assess this, we designed a task, the Feeling of Retrieval. Participants had to predict whether cue words would facilitate AM access (i.e., fluent access cues) or not (i.e., limited access cues) in a limited time (either 1 (Exp. 2) or 2 (Exp. 1) s). Later, they retrieved memories in response to both types of cues. Results show that cues judged as fluent access led to better AM generation, as illustrated by AM retrieval latency and a subjective measure of the ease with which the AMs were retrieved. These rapid predictions may rely on epistemic feelings and / or other mnemonic cues such as a partial retrieval of information. This metacognitive access to the earliest stages of AM retrieval illustrates the ability to monitor AM processes as proposed by Conway (2005).
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