SmB6, a well-known Kondo insulator, exhibits a transport anomaly at low temperature. This anomaly is usually attributed to states within the hybridization gap. Recent theoretical work and transport ...measurements suggest that these in-gap states could be ascribed to topological surface states, which would make SmB6 the first realization of topological Kondo insulator. Here by performing angle-resolved photoemission spectroscopy experiments, we directly observe several dispersive states within the hybridization gap of SmB6. These states show negligible kz dependence, which indicates their surface origin. Furthermore, we perform photoemission circular dichroism experiments, which suggest that the in-gap states possess chirality of the orbital angular momentum. These states vanish simultaneously with the hybridization gap at around 150 K. Together, these observations suggest the possible topological origin of the in-gap states.
Although many studies on lepidopteran pheromone‐binding proteins (PBPs)/ general odorant‐binding proteins (GOBPs) have been reported, the functional differentiation within and between the two ...odorant‐binding protein (OBP) subclasses is still elusive. Here we conducted a comparative study on three SexiPBPs and two SexiGOBPs in Spodoptera exigua. Results showed that all five SexiPBP/GOBP genes have the same intron numbers and conserved exon/intron splice sites. Reverse transcription PCR results showed that these five SexiPBP/GOBPs were primarily expressed in antennae of both sexes and some were also detected in other tissues. Further, quantitative real‐time PCR showed that five SexiPBP/GOBPs had different sex‐biased expression patterns, with PBP1 being highly male‐biased (5.96‐fold difference) and PBP3 slightly female‐biased (2.43‐fold difference), while PBP2 and two GOBPs were approximately sex‐equivalent (the absolute value < 1.90‐fold difference). Binding assays showed that all three SexiPBPs could bind all six sex pheromone components, but SexiPBP1 had much higher affinities dissociation constant (Kᵢ) < 1.10 μM than did the other two SexiPBPs (Kᵢ > 1.20 μM). Very intriguingly, SexiGOBP2 displayed even stronger binding to five sex pheromone components (Kᵢ < 0.40 μM) than SexiPBP1. In contrast, SexiGOBP1 only exhibited weak binding to three alcohol‐pheromone components. Similar results were obtained for tested pheromone analogues. In addition, each of SexiPBP/GOBPs selectively bound some plant odorants with considerable affinities (Kᵢ < 10.0 μM). Taken together, of the three SexiPBPs, SexiPBP1 may play the most important role in female sex pheromone reception, and additionally all three SexiPBPs can detect some plant odorants, while SexiGOBP2 may be involved in the detection of female sex pheromones in addition to plant odorants. The results strongly suggest functional differentiation within and between the two OBP sub‐classes.
We report the detailed electronic structure of WTe2 by high resolution angle-resolved photoemission spectroscopy. We resolved a rather complicated Fermi surface of WTe2. Specifically, there are in ...total nine Fermi pockets, including one hole pocket at the Brillouin zone center Γ, and two hole pockets and two electron pockets on each side of Γ along the Γ-X direction. Remarkably, we have observed circular dichroism in our photoemission spectra, which suggests that the orbital angular momentum exhibits a rich texture at various sections of the Fermi surface. This is further confirmed by our density-functional-theory calculations, where the spin texture is qualitatively reproduced as the conjugate consequence of spin-orbital coupling. Since the spin texture would forbid backscatterings that are directly involved in the resistivity, our data suggest that the spin-orbit coupling and the related spin and orbital angular momentum textures may play an important role in the anomalously large magnetoresistance of WTe2. Furthermore, the large differences among spin textures calculated for magnetic fields along the in-plane and out-of-plane directions also provide a natural explanation of the large field-direction dependence on the magnetoresistance.
Purpose
Tumoral calcinosis is a rare clinicopathological entity characterized by ectopic soft-tissue calcification, typically periarticular. Normophosphatemic tumoral calcinosis is seldom reported in ...East Asian populations, and the preoperative diagnosis is often elusive. This study was performed to characterize the clinical profile of normophosphatemic tumoral calcinosis and investigate the presence of the
SAMD9
gene mutation.
Methods
The clinical features, pathological examination findings, and outcomes of 19 subjects were retrospectively reviewed. All patients were analyzed for
SAMD9
gene mutation using paraffin-embedded tumoral calcinosis specimens.
Results
Nineteen subjects were analyzed (7 males, 12 females). Their mean age at surgery, mean age at symptom onset, and median disease duration was 51.9 ± 17.3 (range 7–75) years, 49.1 ± 17.2 (range 7–74) years, and 1.3 (interquartile range 0.5–3.0) years, respectively. Lesions were located in the hand in 8 (42.1%) subjects; wrist in 5 (26.3%); shoulder in 2 (10.5%); and hip, knee, buttock, and scrotum in 1 (5.3%) subject each. The lesions in 17 (89.5%) subjects were located around the joints small joints (hand and wrist) in 13 (68.4%) and large joints (shoulder, hip, and knee) in 4 (21.1%). Lesions occurred in the upper limbs in 15 (78.9%) subjects and in the lower limbs in 2 (10.5%). Multiple-lesion involvement (distal right index finger and middle finger) occurred in one (5.3%) subject. Symptoms included pain in 15 (78.9%) subjects, impaired mobility in 5 (26.3%), swelling in 5 (26.3%), numbness in 2 (10.5%), and an asymptomatic mass in 2 (10.5%). The serum inorganic phosphorus concentration was normal in all 19 subjects (mean 1.17 ± 0.15 mmol/L). The serum calcium concentration was normal in 18 subjects and low in 1. The serum alkaline phosphatase concentration was normal in all 19 subjects. Pathological examination indicated multiple nodules of calcified materials that manifested an amorphous or granular blue-purple crystal and were surrounded by proliferation of mononuclear or multinuclear macrophages, osteoclastic-like giant cells, fibroblasts, and chronic inflammatory cells. Notably, different phases of pathological manifestations were observed in the same microscopic field. During follow-up (0.5–65.0 months), no recurrence of tumoral calcinosis was observed in 18 (94.7%) subjects, but 1 subject developed in situ recurrence of an asymptomatic subcutaneous mass after 6 months postoperatively. Genetic analysis in all 19 subjects revealed no
SAMD9
gene mutations.
Conclusions
Most subjects were females and developed calcinosis in adulthood. Small joints (hand and wrist) and the upper limbs were frequently involved. The presence of different phases of pathological features in the same subject suggests that about half of the study participants had been misdiagnosed with another condition (such as gout, osteoarthritis, etc.). Complete surgical excision led to cure without recurrence during follow-up in majority of the study participants.
On December 8, 2019, many cases of pneumonia with unknown etiology were first reported in Wuhan, China, subsequently identified as a novel coronavirus infection aroused worldwide concern. As the ...outbreak is ongoing, more and more researchers focused interest on the COVID-19. Therefore, we retrospectively analyzed the publications about COVID-19 to summarize the research hotspots and make a review, to provide reference for researchers in the world.
We conducted a search in PubMed using the keywords "COVID-19" from inception to March 1, 2020. Identified and analyzed the data included title, corresponding author, language, publication time, publication type, research focus.
183 publications published from 2020 January 14 to 2020 February 29 were included in the study. The first corresponding authors of the publications were from 20 different countries. Among them, 78 (42.6%) from the hospital, 64 (35%) from the university and 39 (21.3%) from the research institution. All the publications were published in 80 different journals. Journal of Medical Virology published most of them (n=25). 60 (32.8%) were original research, 29 (15.8%) were review, 20 (10.9%) were short communications. 68 (37.2%) epidemiology, 49 (26.8%) virology and 26 (14.2%) clinical features.
According to our review, China has provided a large number of research data for various research fields, during the outbreak of COVID-19. Most of the findings play an important role in preventing and controlling the epidemic around the world. With research on the COVID-19 still booming, new vaccine and effective medicine for COVID-19 will be expected to come out in the near future with the joint efforts of researchers worldwide.
The diversities in crystal structures and ways of doping result in extremely diversified phase diagrams for iron-based superconductors. With angle-resolved photoemission spectroscopy, we have ...systematically studied the effects of chemical substitution on the electronic structure of various series of iron-based superconductors. Beyond the Fermi-surface alteration that has been reported most often in the past, we found two more extraordinary effects of doping: (1) the site and band dependencies of quasiparticle scattering and, more importantly, (2) the ubiquitous and significant change of electronic correlation by both isovalent and heterovalent dopants in the iron-anion layer. Moreover, we found that the electronic correlation could be suppressed by applying either the chemical pressure or doping electrons but not by doping holes. Together with other findings provided here, these results complete the microscopic picture of the electronic effects of dopants, which facilitates a unified understanding of the diversified phase diagrams and resolutions to many open issues of various iron-based superconductors.
ABSTRACT
We report the phase-connected timing ephemeris, polarization pulse profiles, Faraday rotation measurements, and Rotating-Vector-Model (RVM) fitting results of 12 millisecond pulsars (MSPs) ...discovered with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in the Commensal Radio Astronomy FAST survey (CRAFTS). The timing campaigns were carried out with FAST and Arecibo over 3 yr. 11 of the 12 pulsars are in neutron star–white dwarf binary systems, with orbital periods between 2.4 and 100 d. 10 of them have spin periods, companion masses, and orbital eccentricities that are consistent with the theoretical expectations for MSP–Helium white dwarf (He WD) systems. The last binary pulsar (PSR J1912−0952) has a significantly smaller spin frequency and a smaller companion mass, the latter could be caused by a low orbital inclination for the system. Its orbital period of 29 d is well within the range of orbital periods where some MSP–He WD systems have shown anomalous eccentricities, however, the eccentricity of PSR J1912−0952 is typical of what one finds for the remaining MSP–He WD systems.
Land models, which have been developed by the modeling community in the past few decades to predict future states of ecosystems and climate, have to be critically evaluated for their performance ...skills of simulating ecosystem responses and feedback to climate change. Benchmarking is an emerging procedure to measure performance of models against a set of defined standards. This paper proposes a benchmarking framework for evaluation of land model performances and, meanwhile, highlights major challenges at this infant stage of benchmark analysis. The framework includes (1) targeted aspects of model performance to be evaluated, (2) a set of benchmarks as defined references to test model performance, (3) metrics to measure and compare performance skills among models so as to identify model strengths and deficiencies, and (4) model improvement. Land models are required to simulate exchange of water, energy, carbon and sometimes other trace gases between the atmosphere and land surface, and should be evaluated for their simulations of biophysical processes, biogeochemical cycles, and vegetation dynamics in response to climate change across broad temporal and spatial scales. Thus, one major challenge is to select and define a limited number of benchmarks to effectively evaluate land model performance. The second challenge is to develop metrics of measuring mismatches between models and benchmarks. The metrics may include (1) a priori thresholds of acceptable model performance and (2) a scoring system to combine data-model mismatches for various processes at different temporal and spatial scales. The benchmark analyses should identify clues of weak model performance to guide future development, thus enabling improved predictions of future states of ecosystems and climate. The near-future research effort should be on development of a set of widely acceptable benchmarks that can be used to objectively, effectively, and reliably evaluate fundamental properties of land models to improve their prediction performance skills.
Ionospheric sporadic E layer is thin irregularity with much higher plasma density in the ionospheric E region (~90‐120 km). Morphology of sporadic E intensity is investigated by using the COSMIC ...radio occultation data during 2007‐2012. Maximum gradient value of total electron content fluctuation is defined as Smax index, and it shows good linear relationship with the sporadic E intensity parameter (ordinary critical frequency, foEs) in the low‐latitude and midlatitude regions. By using this Smax index as the sporadic E layer intensity, distribution of sporadic E intensity is obtained. Some known features are confirmed such as the hemisphere summer enhancement, diurnal and semidiurnal behavior, and intensity depression anomaly regions. New findings are also obtained, especially the different behavior pattern in the low‐latitude region. (1) Both positive and negative correlations exist between sporadic E intensity and solar activity, and this correlation also shows complex magnetic latitude dependency. (2) Weaker seasonal variation is found in the low‐latitude region. Besides, hemisphere asymmetries of sporadic E intensity/location are also found during the equinox. (3) Longitudinal wave number‐4 feature of sporadic E intensity is prominent in the lower latitude region, which may be related to the diurnal eastward wave number‐3 tide. In a word, it is feasible to investigate the sporadic E layer intensity distribution based on radio occultation data, which also allows for a global morphology analysis.
Key Points
Correlation between sporadic E intensity and solar activity shows complex magnetic latitude dependency
Weaker seasonal variation is identified in low‐latitude region, as well as hemisphere asymmetries of sporadic E intensity during equinox
Longitudinal WN4 feature is prominent in the lower latitude region, which may be related to the diurnal eastward WN3 tide
Abstract
PSR J2150+3427 is a 0.654 s pulsar discovered by the Commensal Radio Astronomy FAST Survey. From the follow-up observations, we find that the pulsar is in a highly eccentric orbit (
e
= ...0.601) with an orbital period of 10.592 days and a projected semimajor axis of 25.488 lt-s. Using 2.7 yr of timing data, we also measured the rate of periastron advance
ω
̇
= 0.0115(4) deg yr
−1
. An estimate for the total mass of the system using the
ω
̇
gives
M
tot
= 2.59(13)
M
⊙
, which is consistent with most of the known double neutron star (DNS) systems and one neutron star (NS)–white dwarf (WD) system named B2303+46. Combining
ω
̇
with the mass function of the system gives the masses of
M
p
< 1.67 and
M
c
> 0.98
M
⊙
for the pulsar and the companion star, respectively. This constraint, along with the spin period and orbital parameters, suggests that it is possibly a DNS system, and we cannot entirely rule out the possibility of an NS–WD system. Future timing observations will vastly improve the uncertainty in
ω
̇
, and are likely to allow the detection of additional relativistic effects, which can be used to modify the values of
M
p
and
M
c
. With a spin-down luminosity of
E
̇
= 5.07(6) × 10
29
erg s
−1
, PSR J2150+3427 is a very low-luminosity pulsar, with only the binary pulsar J2208+4610 having a smaller
E
̇
.
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