julilili42/papers huggingface dataset:
Formamidinium‐Based Dion‐Jacobson Layered Hybrid Perovskites: Structural Complexity and Optoelectronic Properties
2020-07-19

Abstract Layered hybrid perovskites have emerged as a promising alternative to stabilizing hybrid organic–inorganic perovskite materials, which are predominantly based on Ruddlesden‐Popper structures. Formamidinium (FA)‐based Dion‐Jacobson perovskite analogs are developed that feature bifunctional organic spacers separating the hybrid perovskite slabs by introducing 1,4‐phenylenedimethanammonium (PDMA) organic moieties. While these materials demonstrate competitive performances as compared to other FA‐based low‐dimensional perovskite solar cells, the underlying mechanisms for this behavior remain elusive. Here, the structural complexity and optoelectronic properties of materials featuring (PDMA)FA n –1 Pb n I 3 n +1 ( n = 1–3) formulations are unraveled using a combination of techniques, including X‐ray scattering measurements in conjunction with molecular dynamics simulations and density functional theory calculations. While theoretical calculations suggest that layered Dion‐Jacobson perovskite structures are more prominent with the increasing number of inorganic layers ( n ), this is accompanied with an increase in formation energies that render n &gt; 2 compositions difficult to obtain, in accordance with the experimental evidence. Moreover, the underlying intermolecular interactions and their templating effects on the Dion‐Jacobson structure are elucidated, defining the optoelectronic properties. Consequently, despite the challenge to obtain phase‐pure n &gt; 1 compositions, time‐resolved microwave conductivity measurements reveal high photoconductivities and long charge carrier lifetimes. This comprehensive analysis thereby reveals critical features for advancing layered hybrid perovskite optoelectronics.
The smallest eating the largest: the oldest mammalian feeding traces on dinosaur bone from the Late Jurassic of the Junggar Basin (northwestern China)
2020-07-19

Abstract Reconstructing trophic interactions in ancient ecosystems is an important and fascinating branch of palaeontological research. Here we describe small bioerosional traces that are preserved on sauropod bone from the early Late Jurassic Qigu Formation (Oxfordian) of Liuhuanggou gorge in the southern Junggar Basin (Xinjiang Province, northwestern China). The most likely producers of these traces are tiny Mesozoic mammals as evinced by the small size of the traces as well as by their paired and opposed arrangement. The feeding traces are only superficially preserved on the bone surface and most likely were inflicted unintentionally during feeding. The occurrence of the bite marks along small ridges and the “gnawed” appearance of the bone surface points to selective feeding on the remaining soft tissues of the dinosaur carcass. The traces represent the oldest direct evidence for mammalian feeding behaviour in the fossil record. Additionally, these traces expand the known range of the early mammalian feeding repertoire significantly and shed light on the palaeobiology and palaeoecology of early mammals, a field that has remained evasive for a long time.
The isolateCaproiciproducenssp. 7D4C2 producesn-caproate at mildly acidic conditions from hexoses: genome and rBOX comparison with related strains and chain-elongating bacteria
2020-07-19

Abstract Background Bulk production of medium-chain carboxylates (MCCs) with 6-12 carbon atoms is of great interest to biotechnology. Open cultures ( e . g ., reactor microbiomes) have been utilized to generate MCCs in bioreactors. When in-line MCC extraction and prevention of product inhibition is required, the bioreactors have been operated at mildly acidic pH (5.0-5.5). However, model chain-elongating bacteria grow optimally at neutral pH values. Here, we isolated a chain-elongating bacterium (strain 7D4C2) that thrives at mildly acidic pH. We studied its metabolism and compared its whole genome and the reverse β-oxidation (rBOX) genes to other bacteria. Results Strain 7D4C2 produces lactate, acetate, n -butyrate, n -caproate, biomass, and H 2 /CO 2 from hexoses. With only fructose as substrate (pH 5.5), the maximum n -caproate specificity ( i . e ., products per other carboxylates produced) was 60.9 ± 1.5%. However, this was considerably higher at 83.1 ± 0.44% when both fructose and n -butyrate (electron acceptor) were combined as a substrate. A comparison of serum bottles with fructose and n -butyrate with an increasing pH value from 4.5 to 9.0 showed a decreasing n -caproate specificity from ∼92% at mildly acidic pH (pH 4.5-5.0) to ∼24% at alkaline pH (pH 9.0). Moreover, when carboxylates were extracted from the broth (undissociated n -caproic acid was ∼0.3 mM), the n -caproate selectivity ( i . e ., product per substrate fed) was 42.6 ± 19.0% higher compared to serum bottles without extraction. Based on the 16S rRNA gene sequence, strain 7D4C2 is most closely related to the isolates Caproicibacter fermentans (99.5%) and Caproiciproducens galactitolivorans (94.7%), which are chain-elongating bacteria that are also capable of lactate production. Whole-genome analyses indicate that strain 7D4C2, C. fermentans , and C. galactitolivorans belong to the same genus of Caproiciproducens . Their rBOX genes are conserved and located next to each other, forming a gene cluster, which is different than for other chain-elongating bacteria such as Megasphaera spp. Conclusions Caproiciproducens spp., comprising strain 7D4C2, C. fermentans, C. galactitolivorans , and several unclassified strains, are chain-elongating bacteria that encode a highly conserved rBOX gene cluster. Caproiciproducens sp. 7D4C2 (DSM 110548) was studied here to understand n -caproate production better at mildly acidic pH within microbiomes and has the additional potential as a pure-culture production strain to convert sugars into n -caproate.
Quasilocalized dynamics from confinement of quantum excitations
2020-07-20

Confinement of excitations induces quasilocalized dynamics in disorder-free\\nisolated quantum many-body systems in one spatial dimension. This occurrence is\\nsignalled by severe suppression of quantum correlation spreading and of\\nentanglement growth, long-time persistence of spatial inhomogeneities, and\\nlong-lived coherent oscillations of local observables. In this work, we present\\na unified understanding of these dramatic effects. The slow dynamical behavior\\nis shown to be related to the Schwinger effect in quantum electrodynamics. We\\ndemonstrate that it is quantitatively captured for long time scales by\\neffective Hamiltonians exhibiting Stark localization of excitations and weak\\ngrowth of the entanglement entropy for arbitrary coupling strength. This\\nanalysis explains the phenomenology of real-time string dynamics investigated\\nin a number of lattice gauge theories, as well as the anomalous dynamics\\nobserved in quantum Ising chains after quenches. Our findings establish\\nconfinement as a robust mechanism for hindering the approach to equilibrium in\\ntranslationally-invariant quantum statistical systems with local interactions.\\n
Single cell transcriptomes of normal endometrial derived organoids uncover novel cell type markers and cryptic differentiation of primary tumours
2020-07-20

Abstract Endometrial carcinoma, the most common gynaecological cancer, develops from endometrial epithelium which is composed of secretory and ciliated cells. Pathologic classification is unreliable and there is a need for prognostic tools. We used single cell sequencing to study organoid model systems derived from normal endometrial endometrium to discover novel markers specific for endometrial ciliated or secretory cells. A marker of secretory cells (MPST) and several markers of ciliated cells (FAM92B, WDR16, and DYDC2) were validated by immunohistochemistry on organoids and tissue sections. We performed single cell sequencing on endometrial and ovarian tumours and found both secretory‐like and ciliated‐like tumour cells. We found that ciliated cell markers (DYDC2, CTH, FOXJ1, and p73) and the secretory cell marker MPST were expressed in endometrial tumours and positively correlated with disease‐specific and overall survival of endometrial cancer patients. These findings suggest that expression of differentiation markers in tumours correlates with less aggressive disease, as would be expected for tumours that retain differentiation capacity, albeit cryptic in the case of ciliated cells. These markers could be used to improve the risk stratification of endometrial cancer patients, thereby improving their management. We further assessed whether consideration of MPST expression could refine the ProMiSE molecular classification system for endometrial tumours. We found that higher expression levels of MPST could be used to refine stratification of three of the four ProMiSE molecular subgroups, and that any level of MPST expression was able to significantly refine risk stratification of the copy number high subgroup which has the worst prognosis. Taken together, this shows that single cell sequencing of putative cells of origin has the potential to uncover novel biomarkers that could be used to guide management of cancers. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley &amp; Sons, Ltd.
Fresh Osteochondral Allograft Transplants in the Knee: Bipolar and Beyond
2020-07-20

Abstract Knee patients who have sustained chondral and osteochondral lesions suffer from debilitating pain, which can ultimately lead to posttraumatic osteoarthritis and whole-joint disease. Older, nonactive patients are traditionally steered toward total knee arthroplasty (TKA), but younger, active patients are not good candidates for TKA based on implant longevity, complications, morbidity, and risk for revision, such that treatment strategies at restoring missing hyaline cartilage and bone are highly desired for this patient population. Over the past four decades, fresh osteochondral allograft (OCA) transplantation has been developed as a treatment method for large (&gt; 2.5 cm2) focal full-thickness articular cartilage lesions. This article documents our own institutional OCA journey since 2016 through enhanced graft preservation techniques (the Missouri Osteochondral Preservation System, or MOPS), technical improvements in surgical techniques, use of bone marrow aspirate concentrate, bioabsorbable pins and nails, and prescribed and monitored patient-specific rehabilitation protocols. Further follow-up with documentation of long-term outcomes will provide insight for continued optimization for future applications for OCA transplantation, potentially including a broader spectrum of patients appropriate for this treatment. Ongoing translational research is necessary to blaze the trail in further optimizing this treatment option for patients.
Benefit/risk profile of dapagliflozin 5 mg in the DEPICT ‐1 and ‐2 trials in individuals with type 1 diabetes and body mass index ≥27 kg/m 2
2020-07-21

Abstract Aim The DEPICT‐1 and ‐2 studies (NCT02268214, NCT02460978) evaluated the efficacy and safety of dapagliflozin in individuals with type 1 diabetes who were receiving intensive insulin therapy. The DEPICT‐1 and ‐2 studies (NCT02268214, NCT02460978) evaluated the efficacy and safety of dapagliflozin in individuals with type 1 diabetes. This post‐hoc study investigated the safety and efficacy of dapagliflozin in individuals with BMI ≥27 kg/m 2 to assess if the benefit/risk ratio associated with dapagliflozin treatment can be further improved than that observed in the overall DEPICT population. Methods Changes in glycated haemoglobin (HbA1c) and body weight, percentage change in daily insulin dose and proportion of participants achieving HbA1c reduction ≥0.5% without severe hypoglycaemia were evaluated at weeks 24 and 52. Changes in mean interstitial glucose, mean amplitude of glycaemic excursions and time in target glycaemic range were evaluated at week 24. Safety was assessed until week 56. Results Week‐52 adjusted mean (SE) change from baseline for HbA1c was −0.26% (0.05) with dapagliflozin versus +0.08% (0.05) with placebo and for body weight was −2.74 kg (0.25) with dapagliflozin versus +0.81 kg (0.26) with placebo. Mean (SE) percentage change in daily insulin dose was −10.5% (1.23) with dapagliflozin versus −1.4% (1.36) with placebo. Time spent in target glycaemic range increased by 2.2 h/day versus placebo. Dapagliflozin was well tolerated, with fewer participants experiencing diabetic ketoacidosis (dapagliflozin, 1.7%; placebo, 1.0%) than dapagliflozin 5 mg receiving participants in the pooled DEPICT populations. Conclusions Compared with the pooled DEPICT population, the benefit/risk profile of adjunct dapagliflozin therapy was more favourable in individuals with type 1 diabetes with body mass index ≥27 kg/m 2 because of the reduced risk of diabetic ketoacidosis in this population.
The aged hematopoietic system promotes hippocampal‐dependent cognitive decline
2020-07-21

Abstract The aged systemic milieu promotes cellular and cognitive impairments in the hippocampus. Here, we report that aging of the hematopoietic system directly contributes to the pro‐aging effects of old blood on cognition. Using a heterochronic hematopoietic stem cell (HSC) transplantation model (in which the blood of young mice is reconstituted with old HSCs), we find that exposure to an old hematopoietic system inhibits hippocampal neurogenesis, decreases synaptic marker expression, and impairs cognition. We identify a number of factors elevated in the blood of young mice reconstituted with old HSCs, of which cyclophilin A (CyPA) acts as a pro‐aging factor. Increased systemic levels of CyPA impair cognition in young mice, while inhibition of CyPA in aged mice improves cognition. Together, these data identify age‐related changes in the hematopoietic system as drivers of hippocampal aging.
Towards Nonlinear Disentanglement in Natural Data with Temporal Sparse\\n Coding
2020-07-21

We construct an unsupervised learning model that achieves nonlinear\\ndisentanglement of underlying factors of variation in naturalistic videos.\\nPrevious work suggests that representations can be disentangled if all but a\\nfew factors in the environment stay constant at any point in time. As a result,\\nalgorithms proposed for this problem have only been tested on carefully\\nconstructed datasets with this exact property, leaving it unclear whether they\\nwill transfer to natural scenes. Here we provide evidence that objects in\\nsegmented natural movies undergo transitions that are typically small in\\nmagnitude with occasional large jumps, which is characteristic of a temporally\\nsparse distribution. We leverage this finding and present SlowVAE, a model for\\nunsupervised representation learning that uses a sparse prior on temporally\\nadjacent observations to disentangle generative factors without any assumptions\\non the number of changing factors. We provide a proof of identifiability and\\nshow that the model reliably learns disentangled representations on several\\nestablished benchmark datasets, often surpassing the current state-of-the-art.\\nWe additionally demonstrate transferability towards video datasets with natural\\ndynamics, Natural Sprites and KITTI Masks, which we contribute as benchmarks\\nfor guiding disentanglement research towards more natural data domains.\\n
Boosting Deep Open World Recognition by Clustering
2020-07-21

While convolutional neural networks have brought significant advances in robot vision, their ability is often limited to closed world scenarios, where the number of semantic concepts to be recognized is determined by the available training set. Since it is practically impossible to capture all possible semantic concepts present in the real world in a single training set, we need to break the closed world assumption, equipping our robot with the capability to act in an open world. To provide such ability, a robot vision system should be able to (i) identify whether an instance does not belong to the set of known categories (i.e., open set recognition), and (ii) extend its knowledge to learn new classes over time (i.e., incremental learning). In this work, we show how we can boost the performance of deep open world recognition algorithms by means of a new loss formulation enforcing a global to local clustering of class-specific features. In particular, a first loss term, i.e., global clustering, forces the network to map samples closer to the class centroid they belong to while the second one, local clustering, shapes the representation space in such a way that samples of the same class get closer in the representation space while pushing away neighbours belonging to other classes. Moreover, we propose a strategy to learn class-specific rejection thresholds, instead of heuristically estimating a single global threshold, as in previous works. Experiments on three benchmarks show the effectiveness of our approach.
Effect of Powered Air‐Purifying Respirators on Speech Recognition Among Health Care Workers
2020-07-21

Powered air‐purifying respirators (PAPRs) are used as personalized protective equipment for health care personnel. PAPRs offer health care workers added protection when dealing with patients who have high‐risk infectious disease such as COVID‐19. Unfortunately, PAPRs can produce notable levels of background noise. We hypothesize that PAPR use may be associated with increased hearing thresholds and impaired word discrimination and may ultimately have a negative impact on effective communication. Herein, we (1) determined sound levels generated by PAPRs and (2) measured hearing thresholds and word discrimination with and without operational PAPRs. All participants had normal hearing. When the PAPR was operational, mean ± SD thresholds increased from 4.5 ± 3.6 to 38.6 ± 5.6 dB HL ( P &lt;. 001). Word discrimination dropped from 100% in all participants in quiet to a mean 48% ± 14% with operational PAPR ( P &lt;. 001). Thus, we find that use of PAPR hoods results in hearing impairment comparable to moderate to severe hearing loss, and we suspect that users will experience communication difficulties as a result. Level of Evidence. Prospective study.
Non-invasive vagus nerve stimulation boosts mood recovery after effort exertion
2020-07-21

Abstract Mood plays an important role in our life which is illustrated by the disruptive impact of aberrant mood states in depression. Although vagus nerve stimulation (VNS) has been shown to improve symptoms of depression, the exact mechanism is still elusive, and it is an open question whether non-invasive VNS could be used to swiftly and robustly improve mood. Here, we investigated the effect of left- and right-sided transcutaneous auricular VNS (taVNS) versus a sham control condition on mood after exertion of physical and cognitive effort in 82 healthy participants (randomized cross-over design). Using linear mixed-effects and hierarchical Bayesian analyses of mood ratings, we found that 90 min of either left-sided or right-sided taVNS improved positive mood ( b = 5.11, 95% credible interval, CI [1.39, 9.01], 9.6% improvement relative to the mood intercept, BF 10 = 7.69, p LME = .017), yet only during the post stimulation phase. Moreover, lower baseline scores of positive mood were associated with greater taVNS-induced improvements in motivation ( r = −.42, 95% CI [−.58, −.21], BF 10 = 249). We conclude that taVNS boosts mood after a prolonged period of effort exertion with concurrent stimulation and that acute motivational effects of taVNS are partly dependent on initial mood states. Collectively, our results show that taVNS may help quickly improve affect after a mood challenge, potentially by modulating interoceptive signals contributing to reappraisal of effortful behavior. This suggests that taVNS could be a useful add-on to current behavioral therapies.
Blood-Brain Barrier Protein Claudin-5 Expressed in Paired Xenopus laevis Oocytes Mediates Cell-Cell Interaction
2020-07-21

Claudin-5 determines the sealing properties of blood-brain barrier tight junctions and its function is impaired in neurodegenerative and neuroinflammatory disorders. Focusing on the contribution of claudin-5 to the trans-interaction within the tight junction seal, we used Xenopus laevis oocytes as an expression system. Cells were clustered and challenged in a novel approach for the analysis of claudin interaction. We evaluated the strengthening effect of claudin-5 to cell-cell-connection in comparison to claudin-3. Application of a hydrostatic pressure impulse on clustered control oocyte pairs revealed a reduction of contact areas. In contrast, combinations with both oocytes expressing claudins maintained an enhanced connection between the cells (cldn5–cldn5, cldn3–cldn3). Strength of interaction was increased by both claudin-3 and claudin-5. This novel approach allowed an analysis of single claudins contributing to tight junction integrity, characterizing homophilic and hetrophilic trans-interaction of claudins. To test a new screening approach for barrier effectors, exemplarily, this 2-cell model of oocytes was used to analyze the effect of the absorption enhancer sodium caprate on the oocyte pairs.
Trans-saccadic adaptation of perceived size independent of saccadic adaptation
2020-07-21

Systematic shortening or lengthening of target objects during saccades modifies saccade amplitudes and perceived size of the objects. These two events are concomitant when size change during the saccade occurs asymmetrically, thereby shifting the center of mass of the object. In the present study, we asked whether or not the two are necessarily linked. We tested human participants in symmetrical systematic shortening and lengthening of a vertical bar during a horizontal saccade, aiming to not modify the saccade amplitude. Before and after a phase of trans-saccadic changes of the target bar, participants manually indicated the sizes of various vertically oriented bars by open-loop grip aperture. We evaluated the effect of trans-saccadic changes of bar length on manual perceptual reports and whether this change depended on saccade amplitude. As expected, we did not induce any change in horizontal or vertical components of saccade amplitude, but we found a significant difference in perceived size after the lengthening experiment compared to after the shortening experiment. Moreover, after the lengthening experiment, perceived size differed significantly from pre-lengthening baseline. These findings suggest that a change of size perception can be induced trans-saccadically, and its mechanism does not depend on saccadic amplitude change.
RNA Sequencing Identifies a Common Physiology in Vancomycin- and Ciprofloxacin-Tolerant Staphylococcus aureus Induced by ileS Mutations
2020-07-21

Little is known about the mechanisms by which ileS mutations induce vancomycin tolerance in Staphylococcus aureus . This study showed that transcriptome profiles were similar in vancomycin-tolerant mutants and the IleRS-inhibitor-treated parent. Notably, ileS and relA , which induce a stringent response, were upregulated. The same mechanism was responsible for cross-tolerance to vancomycin and ciprofloxacin. These findings suggest that the accumulation of uncharged isoleucyl-tRNA following ileS mutations in S. aureus was responsible for drug tolerance.