julilili42/papers huggingface dataset:
Elevated FGF23 Levels in Mice Lacking the Thiazide-Sensitive NaCl cotransporter (NCC)
2018-02-20

Abstract Fibroblast growth factor 23 (FGF23) participates in the orchestration of mineral metabolism by inducing phosphaturia and decreasing the production of 1,25(OH) 2 D 3 . It is known that FGF23 release is stimulated by aldosterone and extracellular volume depletion. To characterize this effect further in a model of mild hypovolemia, we studied mice lacking the thiazide sensitive NaCl cotransporter (NCC). Our data indicate that NCC knockout mice (KO) have significantly higher FGF23, PTH and aldosterone concentrations than corresponding wild type (WT) mice. However, 1,25(OH) 2 D 3 , fractional phosphate excretion and renal brush border expression of the sodium/phosphate co-transporter 2a were not different between the two genotypes. In addition, renal expression of FGF23 receptor FGFR1 and the co-receptor Klotho were unaltered in NCC KO mice. FGF23 transcript was increased in the bone of NCC KO mice compared to WT mice, but treatment of primary murine osteoblasts with the NCC inhibitor hydrochlorothiazide did not elicit an increase of FGF23 transcription. In contrast, the mineralocorticoid receptor blocker eplerenone reversed excess FGF23 levels in KO mice but not in WT mice, indicating that FGF23 upregulation in NCC KO mice is primarily aldosterone-mediated. Together, our data reveal that lack of renal NCC causes an aldosterone-mediated upregulation of circulating FGF23.
Spatial Arrangement and Set Size Influence the Coding of Non-symbolic Quantities in the Intraparietal Sulcus
2018-02-20

Performance in visual quantification tasks shows two characteristic patterns as a function of set size. A precise subitizing process for small sets (up to four) was contrasted with an approximate estimation process for larger sets. The spatial arrangement of elements in a set also influences visual quantification performance, with frequently perceived arrangements (e.g., dice patterns) being faster enumerated than random arrangements. Neuropsychological and imaging studies identified the intraparietal sulcus (IPS), as key brain area for quantification, both within and above the subitizing range. However, it is not yet clear if and how set size and spatial arrangement of elements in a set modulate IPS activity during quantification. In an fMRI study, participants enumerated briefly presented dot patterns with random, canonical or dice arrangement within and above the subitizing range. We evaluated how activity amplitude and pattern in the IPS were influenced by size and spatial arrangement of a set. We found a discontinuity in the amplitude of IPS response between subitizing and estimation range, with steep activity increase for sets exceeding four elements. In the estimation range, random dot arrangements elicited stronger IPS response than canonical arrangements which in turn elicited stronger response than dice arrangements. Furthermore, IPS activity patterns differed systematically between arrangements. We found a signature in the IPS response for a transition between subitizing and estimation processes during quantification. Differences in amplitude and pattern of IPS activity for different spatial arrangements indicated a more precise representation of non-symbolic numerical magnitude for dice and canonical than for random arrangements. These findings challenge the idea of an abstract coding of numerosity in the IPS even within a single notation.
Lithium and Sodium Ion Distributions in A2–x[W6I14] Structures
2018-02-20

Ag<sub>2</sub>[W<sub>6</sub>I<sub>14</sub>] and A<sub>2- x</sub>[W<sub>6</sub>I<sub>14</sub>] compounds with A = Na, Li were prepared from binary tungsten iodides (W<sub>3</sub>I<sub>12</sub>) and corresponding metal iodides. Their crystal structures are analyzed on the basis of X-ray diffraction data. <sup>7</sup>Li and <sup>23</sup>Na solid-state NMR measurements reveal that Li<sup>+</sup> and Na<sup>+</sup> ions are distributed over two sites in the respective structures. These results shed some new light on A <sub>x</sub>[M<sub>6</sub>I<sub>14</sub>] with A = alkali and M = Mo, W compounds being reported with x = 1 and 2, which exhibit photophysical properties. The lithium compound is an exception in the series of A<sub>2- x</sub>[W<sub>6</sub>I<sub>14</sub>] compounds, because it is the only compound which is soluble in water.
Whole blood AR-V7 and AR-V9 mRNA expression and treatment response in metastatic castrate-resistant prostate cancer (mCRPC).
2018-02-20

252 Background: Androgen receptor splice variant (AR-V) expression has previously been regarded as a negative predictive biomarker for response to abiraterone and enzalutamide in mCRPC patients. However, recent data questions this association. We designed a whole blood assay to detect AR-V7 and AR-V9, the two most abundantly expressed AR-Vs, and correlated expression with clinical outcomes in patients commencing abiraterone or enzalutamide. Methods: We developed a quantitative real-time polymerase chain reaction assay to detect AR-V7 and AR-V9 from whole blood collected in PAXgene tubes. The assay was applied to samples prospectively collected from 37 mCRPC patients prior to commencing abiraterone or enzalutamide, and at treatment cessation. Patients positive for either AR-V7 or AR-V9 were defined as AR-V-positive, and AR-V-negative if neither variant was detected. AR-V expression was correlated with PSA response rate (chi-square test) and PSA progression-free survival (PSA-PFS) (log-rank test). Assay sensitivity was determined by serially diluting RNA from VCaP prostate cancer cells (known to express AR-V7) to establish a lower limit of detection. Results: The median follow-up was 7.29 months (IQR 4.21-10.55); 9 of 37 patients (24%) were AR-V-positive. We observed similar response rates in AR-V-positive (6/9) and AR-V-negative (18/28) patients (66% vs. 64%, p = 0.896). PSA-PFS did not differ significantly between groups (9.2 months vs. not reached, p = 0.355). Two patients converted from AR-V-negative to AR-V-positive (PSA-PFS 3.35 and 0.60 months respectively), and one patient remained AR-V-positive at baseline and end-of-treatment sampling. The lower limit of detection for AR-V7 was 0.1%, and AR-V7/V9 was not detected in any of the 13 normal male controls. Conclusions: We developed a sensitive and specific whole blood assay for AR-V7 and AR-V9 detection in patients with mCRPC. Neither PSA response rates nor PSA-PFS differed significantly between AR-V-positive and AR-V-negative patients. These data support recent literature questioning the role of AR-V expression as a negative predictive biomarker in mCRPC patients receiving abiraterone or enzalutamide.
Magnetite and Green Rust: Synthesis, Properties, and Environmental Applications of Mixed-Valent Iron Minerals
2018-02-21

Mixed-valent iron [Fe(II)-Fe(III)] minerals such as magnetite and green rust have received a significant amount of attention over recent decades, especially in the environmental sciences. These mineral phases are intrinsic and essential parts of biogeochemical cycling of metals and organic carbon and play an important role regarding the mobility, toxicity, and redox transformation of organic and inorganic pollutants. The formation pathways, mineral properties, and applications of magnetite and green rust are currently active areas of research in geochemistry, environmental mineralogy, geomicrobiology, material sciences, environmental engineering, and environmental remediation. These aspects ultimately dictate the reactivity of magnetite and green rust in the environment, which has important consequences for the application of these mineral phases, for example in remediation strategies. In this review we discuss the properties, occurrence, formation by biotic as well as abiotic pathways, characterization techniques, and environmental applications of magnetite and green rust in the environment. The aim is to present a detailed overview of the key aspects related to these mineral phases which can be used as an important resource for researchers working in a diverse range of fields dealing with mixed-valent iron minerals.
The Dewar Isomer of 1,2‐Dihydro‐1,2‐azaborinines: Isolation, Fragmentation, and Energy Storage
2018-02-21

Abstract The photochemistry of 1,2‐dihydro‐1,2‐azaborinine derivatives was studied under matrix isolation conditions and in solution. Photoisomerization occurs exclusively to the Dewar valence isomers upon irradiation with UV light (&gt;280 nm) with high quantum yield (46 %). Further photolysis with UV light (254 nm) results in the formation of cyclobutadiene and an iminoborane derivative. The thermal electrocyclic ring‐opening reaction of the Dewar valence isomer back to the 1,2‐dihydro‐1‐ tert ‐butyldimethylsilyl‐2‐mesityl‐1,2‐azaborinine has an activation barrier of (27.0±1.2) kcal mol −1 . In the presence of the Wilkinson catalyst, the ring opening occurs rapidly and exothermically (Δ H =(−48±1) kcal mol −1 ) at room temperature.
Seizures and disturbed brain potassium dynamics in the leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts
2018-02-21

Objective Loss of function of the astrocyte‐specific protein MLC1 leads to the childhood‐onset leukodystrophy “megalencephalic leukoencephalopathy with subcortical cysts” (MLC). Studies on isolated cells show a role for MLC1 in astrocyte volume regulation and suggest that disturbed brain ion and water homeostasis is central to the disease. Excitability of neuronal networks is particularly sensitive to ion and water homeostasis. In line with this, reports of seizures and epilepsy in MLC patients exist. However, systematic assessment and mechanistic understanding of seizures in MLC are lacking. Methods We analyzed an MLC patient inventory to study occurrence of seizures in MLC. We used two distinct genetic mouse models of MLC to further study epileptiform activity and seizure threshold through wireless extracellular field potential recordings. Whole‐cell patch‐clamp recordings and K + ‐sensitive electrode recordings in mouse brain slices were used to explore the underlying mechanisms of epilepsy in MLC. Results An early onset of seizures is common in MLC. Similarly, in MLC mice, we uncovered spontaneous epileptiform brain activity and a lowered threshold for induced seizures. At the cellular level, we found that although passive and active properties of individual pyramidal neurons are unchanged, extracellular K + dynamics and neuronal network activity are abnormal in MLC mice. Interpretation Disturbed astrocyte regulation of ion and water homeostasis in MLC causes hyperexcitability of neuronal networks and seizures. These findings suggest a role for defective astrocyte volume regulation in epilepsy. Ann Neurol 2018;83:636–649
Nonclassical states of light with a smooth P function
2018-02-21

There is a common understanding in quantum optics that nonclassical states of\\nlight are states that do not have a positive semidefinite and sufficiently\\nregular Glauber-Sudarshan function. Almost all known nonclassical states\\nhave functions that are highly irregular which makes working with them\\ndifficult and direct experimental reconstruction impossible. Here we introduce\\nclasses of nonclassical states with regular, non-positive-definite \\nfunctions. They are constructed by "puncturing" regular smooth positive \\nfunctions with negative Dirac-delta peaks, or other sufficiently narrow smooth\\nnegative functions. We determine the parameter ranges for which such punctures\\nare possible without losing the positivity of the state, as well as the regimes\\nyielding antibunching of light. Finally, we propose some possible experimental\\nrealizations of such states.\\n
Effect of changing vegetation on denudation (part 2): Landscape response to transient climate and vegetation cover
2018-02-21

Abstract. We present a numerical modelling investigation into the interactions between transient climate and vegetation cover with hillslope and fluvial processes. Model simulations were designed to investigate the effects of climate change and associated changes in surface vegetation cover on topographic basin metrics such as: slope, relief and channel steepness. The Landlab surface process model was used to evaluate the effects of temporal variations in vegetation cover on hillslope diffusion and detachment limited fluvial erosion. A suite of simulations were conducted to represent present-day climatic conditions and satellite-derived vegetation cover at the four EarthShape study areas as well hypothetical transient long term changes. Two different transient variations in climate and vegetation cover include a step change in climate or vegetation, as well as 100 kyr oscillations over 5 Myr. Results indicate that the coupled influence of surface vegetation cover and mean annual precipitation shifts basin landforms towards a new steady state, with the magnitude of change highly sensitive to the initial vegetation and climate conditions of the basin. Dry, non-vegetated basins show higher magnitudes of adjustment than basins that are situated in wetter conditions with higher vegetation cover. For coupled conditions when surface vegetation cover and mean annual precipitation change simultaneously, the landscape response tends to be weaker. When vegetation cover and mean annual precipitation change independently from each other, higher magnitude shifts in topographic metrics are simulated. Changes in vegetation cover show a higher impact on topography for low initial surface cover values whereas for areas with high initial surface cover, the effect of changes in precipitation dominate the formation of landscapes. This study demonstrates a sensitivity of catchment characteristics to different transient forcings in vegetation cover and mean annual precipitation, with a crucial role for initial vegetation and climate conditions. Ongoing research is developing fully-coupled landscape evolution and dynamic vegetation model (see companion paper) forced with predicted paleoclimate histories from an atmospheric general circulation model.
THE SPATIAL ORGANISATION AND THE PERICELLULAR MATRIX OF HUMAN FOETAL CHONDROCYTES ARE NOT INBORN BUT INSTEAD ACQUIRED CHARACTERISTICS
2018-02-21

Summary In adult articular cartilage, the pericellular matrix (PCM) mediates chondrocyte-matrix-interactions and is associated with the spatial cellular organization. Immunofluorescence microscopy, multiphoton-induced autofluorescence and second harmonic generation (SHG) imaging, as well as point pattern analyses revealed that both PCM and spatial organization were absent in fetal chondrocytes. Introduction In adult articular cartilage, the pericellular matrix mediates the biomechanical, biophysical and biomechanical interactions between the chondrocyte and the extracellular matrix. The PCM is also associated with the spatial organization of human superficial chondrocytes, which are situated in four distinct patterns of strings, clusters, pairs or single cells. However, little is known about the PCM and the spatial organization during fetal development. In this study, we asked the question whether fetal chondrocytes display a spatial organization comparable to that of adult chondrocytes, and whether a PCM is present or absent in the early stages of fetal cartilage development. Methods Articular cartilage sections (100μm thickness) were prepared from the condyles of human fetal knee joints (pregnancy weeks 7–10) and from macroscopically intact condylar areas (knee joint replacement procedures). The samples were characterised by immunofluorescence microscopy and multiphoton-induced autofluorescence imaging combined with quantitative SHG signal profiling, a technique that allows quantifying the fibrillar collagen content. The spatial organization was analyzed by point pattern analyses as we described previously. For these analyses the Cartesian coordinates of each nucleus were determined by converting the immunofluorescence images into gray-scale images and finding the local gray-scale maxima with ImageJ (NIH). Results In adult superficial cartilage, the PCM surrounded single or groups of chondrocytes and defined their spatial organization of groups of cellular strings. PCM was characterised by a strong collagen VI staining signal and high collagen intensity as measured by SHG (156.7±12.4). In fetal cartilage, the condyles were characterised by a high cellular density, no recognizable spatial organization, and little amounts of extracellular matrix. No collagen VI was detected in the matrix surrounding the fetal chondrocytes. Furthermore, SHG imaging revealed that the fibrillar collagen intensity was significantly weaker (4.7±0.8; p Discussion/Conclusion In human fetal articular cartilage the spatial organization typical for adult chondrocytes was not present. Instead, the chondrocytes were situated densely and in close proximity. This study determined for the first time that the collagenous components that are typical for the adult PCM were not present in fetal cartilage. In conclusion, the PCM and also the spatial organization of superficial human chondrocytes develop with cartilage maturation and thus are not inborn but instead acquired characteristics.
Extracellular Pax6 regulates tangential Cajal-Retzius cell migration in the developing mouse neocortex
2018-02-21

Abstract The embryonic mouse cortex displays a striking low caudo-medial and high rostro-lateral graded expression of the homeoprotein transcription factor Pax6, which presents both cell autonomous and direct non-cell autonomous activities. Through the genetic induction of anti-Pax6 single-chain antibody secretion, we have analyzed Pax6 non-cell autonomous activity on the migration of cortical hem- and septum-derived Cajal-Retzius (CR) neurons by live imaging of flat mount developing cerebral cortices. We observed that blocking extracellular Pax6 disrupts tangential CR cell migration patterns. We found a decrease in the distance travelled and changes both in directionality and in the depth at which CR cells migrate. Tracking of single CR cells in mutant cortices revealed that extracellular Pax6 neutralization enhances or reduces contact repulsion in medial and lateral regions, respectively. This study demonstrates that secreted Pax6 controls neuronal migration thus acting as a bona fide morphogen at an early stage of cerebral cortex development. Summary statement Cajal-Retzius cell distribution in the embryonic cortex participates in determining the size and positioning of cortical areas. Here, Kaddour et al. establish that the direct non-cell autonomous activity of the Pax6 transcription factor regulates Cajal-Retzius cell migration.
How authoritarian rulers seek to legitimize repression: framing mass killings in Egypt and Uzbekistan
2018-02-22

How do authoritarian rulers legitimate repressive actions against their own citizens? Although most research depicts repression and legitimation as opposed strategies of political rule, justified coercion against some groups may generate legitimacy in the eyes of other parts of the population. Building upon this suggested link between legitimation and repression, this article studies the justifications of mass killings. To this end, framing theory is combined with recent research on the domestic and international dimensions of authoritarian rule. We contend that frames are directed towards specific audiences at home and abroad. Moreover, given the common threats at the global level and the diffusion of repressive tactics, we assume that learning processes influence discursive justifications of repression in authoritarian regimes. We provide an analysis of government rhetoric by comparing the protest crackdowns of Rabi'a 'Adawiya Square in Egypt and Fergana Valley in Uzbekistan, taking into account the audiences and the sources of the frames that justify repression. In both cases, we find the terrorism frame to emerge as dominant.
Precise Motor Control Enables Rapid Flexibility in Vocal Behavior of Marmoset Monkeys
2018-02-22

Investigating the evolution of human speech is difficult and controversial because human speech surpasses nonhuman primate vocal communication in scope and flexibility [1-3]. Monkey vocalizations have been assumed to be largely innate, highly affective, and stereotyped for over 50 years [4, 5]. Recently, this perception has dramatically changed. Current studies have revealed distinct learning mechanisms during vocal development [6-8] and vocal flexibility, allowing monkeys to cognitively control when [9, 10], where [11], and what to vocalize [10, 12, 13]. However, specific call features (e.g., duration, frequency) remain surprisingly robust and stable in adult monkeys, resulting in rather stereotyped and discrete call patterns [14]. Additionally, monkeys seem to be unable to modulate their acoustic call structure under reinforced conditions beyond natural constraints [15, 16]. Behavioral experiments have shown that monkeys can stop sequences of calls immediately after acoustic perturbation but cannot interrupt ongoing vocalizations, suggesting that calls consist of single impartible pulses [17, 18]. Using acoustic perturbation triggered by the vocal behavior itself and quantitative measures of resulting vocal adjustments, we show that marmoset monkeys are capable of producing calls with durations beyond the natural boundaries of their repertoire by interrupting ongoing vocalizations rapidly after perturbation onset. Our results indicate that marmosets are capable of interrupting vocalizations only at periodic time points throughout calls, further supported by the occurrence of periodically segmented phees. These ideas overturn decades-old concepts on primate vocal pattern generation, indicating that vocalizations do not consist of one discrete call pattern but are built of many sequentially uttered units, like human speech.
Woody debris is related to reach‐scale hotspots of lowland stream ecosystem respiration under baseflow conditions
2018-02-22

Abstract Stream metabolism is a fundamental, integrative indicator of aquatic ecosystem functioning. However, it is not well understood how heterogeneity in physical channel form, particularly in relation to and caused by in‐stream woody debris, regulates stream metabolism in lowland streams. We combined conservative and reactive stream tracers to investigate relationships between patterns in stream channel morphology and hydrological transport ( form ) and metabolic processes as characterized by ecosystem respiration ( function ) in a forested lowland stream at baseflow. Stream reach‐scale ecosystem respiration was related to locations (“hotspots”) with a high abundance of woody debris. In contrast, nearly all other measured hydrological and geomorphic variables previously documented or hypothesized to influence stream metabolism did not significantly explain ecosystem respiration. Our results suggest the existence of key differences in physical controls on ecosystem respiration between lowland stream systems (this study) and smaller upland streams (most previous studies) under baseflow conditions. As such, these findings have implications for reactive transport models that predict biogeochemical transformation rates from hydraulic transport parameters, for upscaling frameworks that represent biological stream processes at larger network scales, and for the effective management and restoration of aquatic ecosystems.