With the rapid development of mechanical equipment, the mechanical health monitoring field has entered the era of big data. However, the method of manual feature extraction has the disadvantages of ...low efficiency and poor accuracy, when handling big data. In this study, the research object was the asynchronous motor in the drivetrain diagnostics simulator system. The vibration signals of different fault motors were collected. The raw signal was pretreated using short time Fourier transform （STFT） to obtain the corresponding time-frequency map. Then, the feature of the time-frequency map was adap- tively extracted by using a convolutional neural network （CNN）. The effects of the pretreatment method, and the hyper parameters of network diagnostic accuracy, were investigated experimentally. The experimental results showed that the influence of the preprocessing method is small, and that the batch-size is the main factor affecting accuracy and training efficiency. By investigating feature visualization, it was shown that, in the case of big data, the extracted CNN features can represent complex mapping relationships between signal and health status, and can also overcome the prior knowledge and engineering experience requirement for feature extraction, which is used by tra- ditional diagnosis methods. This paper proposes a new method, based on STFT and CNN, which can complete motor fault diagnosis tasks more intelligently and accurately.
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FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Cross-species transmission of viruses from wildlife animal reservoirs poses a marked threat to human and animal health
. Bats have been recognized as one of the most important reservoirs for emerging ...viruses and the transmission of a coronavirus that originated in bats to humans via intermediate hosts was responsible for the high-impact emerging zoonosis, severe acute respiratory syndrome (SARS)
. Here we provide virological, epidemiological, evolutionary and experimental evidence that a novel HKU2-related bat coronavirus, swine acute diarrhoea syndrome coronavirus (SADS-CoV), is the aetiological agent that was responsible for a large-scale outbreak of fatal disease in pigs in China that has caused the death of 24,693 piglets across four farms. Notably, the outbreak began in Guangdong province in the vicinity of the origin of the SARS pandemic. Furthermore, we identified SADS-related CoVs with 96-98% sequence identity in 9.8% (58 out of 591) of anal swabs collected from bats in Guangdong province during 2013-2016, predominantly in horseshoe bats (Rhinolophus spp.) that are known reservoirs of SARS-related CoVs. We found that there were striking similarities between the SADS and SARS outbreaks in geographical, temporal, ecological and aetiological settings. This study highlights the importance of identifying coronavirus diversity and distribution in bats to mitigate future outbreaks that could threaten livestock, public health and economic growth.
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KISLJ, NUK, SBMB, UL, UM, UPUK
Recently, the coronavirus disease 2019 (COVID‐19) has caused a global pandemic. Several studies indicate that the digestive system can also be affected by the severe acute respiratory syndrome ...coronavirus 2 (SARS‐CoV‐2). Therefore, patients with digestive symptoms should have a capsule endoscopy (CE). COVID‐19 patients with gastrointestinal (GI) symptoms who underwent CE were recruited from March 2020 to April 2020. We collected patients’ data and performed a prospective follow‐up study for 6 months. All 11 COVID‐19 cases with GI symptoms who underwent CE presented gastritis. Eight cases (72.7%) had intestinal mucosa inflammation. Among them, two cases showed intestinal ulcers or erosions. Moreover, two cases displayed colonic mucositis. One case was lost during follow‐up. At 3–6 months after hospital discharge, five patients underwent CE again, presenting gastrointestinal lesions. Five of the 10 cases had GI symptoms, such as abdominal pain, diarrhea, constipation, and others. Among these five cases, the GI symptoms of three patients disappeared at the last follow‐up and two patients still presented diarrhea symptoms. Overall, we observed damaged digestive tract mucosa that could be caused by SARS‐CoV‐2. Moreover, after discharge, some patients still presented intestinal lesions and GI symptoms.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A
bstract
We study the lepton portal dark matter (DM) model in which the relic abundance is determined by the portal coupling among the Majorana fermion DM candidate
χ
, the singlet charged scalar ...mediator
S
±
and the Standard Model (SM) right-handed lepton. The direct and indirect searches are not sensitive to this model. This article studies the lepton portal coupling as well as the scalar portal coupling (between
S
±
and SM Higgs boson), as the latter is generally allowed in the Lagrangian. The inclusion of scalar portal coupling not only significantly enhances the LHC reach via the
gg
→
h
*
→
S
+
S
−
process, but also provides a few novel signal channels, such as the exotic decays and coupling devi- ations of the Higgs boson, offering new opportunities to probe the model. In addition, we also study the Drell-Yan production of
S
+
S
−
at future lepton colliders, and find out that the scenario where one
S
±
is off-shell can be used to measure the lepton portal coupling directly. In particular, we are interested in the possibility that the scalar potential triggers a first-order phase transition and hence provides the stochastic gravitational wave (GW) signals. In this case, the terrestrial collider experiments and space-based GW detectors serve as complementary approaches to probe the model.
2D second‐order topological insulators (SOTIs) have sparked significant interest, but currently, the proposed realistic 2D materials for SOTIs are limited to nonmagnetic systems. In this study, for ...the first time, a single layer of chalcogenide CrSiTe3—an experimentally realized transition metal trichalcogenide is proposed with a layer structure—as a 2D ferromagnetic (FM) SOTI. Based on first‐principles calculations, this study confirms that the CrSiTe3 monolayer exhibits a nontrivial gapped bulk state in the spin‐up channel and a trivial gapped bulk state in the spin‐down channel. Based on the higher‐order bulk–boundary correspondence, it demonstrates that the CrSiTe3 monolayer exhibits topologically protected corner states with a quantized fractional charge (e3$\frac{e}{3}$) in the spin‐up channel. Notably, unlike previous nonmagnetic examples, the topological corner states of the CrSiTe3 monolayer are spin‐polarized and pinned at the corners of the sample in real space. Furthermore, the CrSiTe3 monolayer retains SOTI features when the spin–orbit coupling (SOC) is considered, as evidenced by the corner charge and corner states distribution. Finally, by applying biaxial strain and hole doping, this study transforms the magnetic insulating bulk states into spin‐gapless semiconducting and half‐metallic bulk states, respectively. Importantly, the topological corner states persist in the spin‐up channel under these conditions.
A single layer of chalcogenide CrSiTe3 is found to be a 2D ferromagnetic second‐order topological insulator. The CrSiTe3 monolayer exhibits a nontrivial gapped bulk state in the spin‐up channel and a trivial gapped bulk state in the spin‐down channel. The topological corner states of the CrSiTe3 monolayer are spin‐polarized and pinned at the corners of the sample in real space.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The southeast margin of the Tibetan plateau is characterized by deeply incised river valleys separated by a perched low relief landscape that gently descends from the high Tibetan plateau towards the ...southeast. When and how this unique landscape formed is debated. The onset of increased river incision is often interpreted as a proxy for the timing of surface uplift. Here, apatite and zircon (U–Th)/He and apatite fission track thermochronometries are employed to map the spatial and temporal pattern of exhumation in the region. Vertical profiles of granitic rocks were collected near Deqin (∼28.5°N) and Weixi (∼27.5°N). The two transects share a similar exhumation history, with two episodes of relatively fast exhumation (∼100–300 m/Myr) in the Cenozoic: during the Paleocene to Eocene (60–40 Ma) and Miocene to present (20–0 Ma), separated by an intervening period of slow exhumation. A pulse of moderate to high exhumation (70–300 m/Myr) during the mid- to late-Cretaceous (120–80 Ma) is also present in the data. However, the rate and total amount of exhumation near Deqin is larger than at Weixi and is especially pronounced in the interval between 20 Ma to present. We interpret this difference as possibly related to differences in erosion rates between the Lancang (Deqin) and the Jinsha (Weixi) rivers. The Paleocene to Eocene episode of fast exhumation is likely in response to early Cenozoic deformation along tectonic boundary structures, related to the transpressional collision of the Indian plate with this region. Pre-Miocene episodes of fast exhumation corroborate recent paleoaltimetric studies, which show that the southeast margin of the Tibetan plateau was elevated prior to the Oligocene.
•Three episodes of fast exhumation during 120–80 Ma, 60–40 Ma and 20–0 Ma.•Diachroneous initiation of fast exhumation along tectonic boundary structures.•Spatial varying magnitude of denudation since 20 Ma.•Results support an elevated region prior to the Oligocene.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Post‐synthetic modification plays a crucial role in precisely adjusting the structure and functions of advanced materials. Herein, we report the self‐assembly of a tubular heterometallic Pd3Cu6L16 ...capsule that incorporates Pd(II) and CuL1 metalloligands. This capsule undergoes further modification with two tridentate anionic ligands (L2) to afford a bicapped Pd3Cu6L16L22 capsule with an Edshammer polyhedral structure. By employing transition metal ions, acid, and oxidation agents, the bicapped capsule can be converted into an uncapped one. This uncapped form can then revert back to the bicapped structure on the addition of Br− ions and a base. Interestingly, introducing Ag+ ions leads to the removal of one L2 ligand from the bicapped capsule, yielding a mono‐capped Pd3Cu6L16L2 structure. Furthermore, the size of the anions critically influences the precise control over the post‐synthetic modifications of the capsules. It was demonstrated that these capsules selectively encapsulate tetrahedral anions, offering a novel approach for the design of intelligent molecular delivery systems.
The self‐assembly of PdII ions with metalloligand CuL1 gives a heterometallic Pd3Cu6L16 capsule, which can undergo precise post‐synthetic modification with two tridentate anionic ligands to form a bicapped Pd3Cu6L16L22 capsule. Reversible post‐synthetic modification between Pd3Cu6L16L22, Pd3Cu6L16L2, and Pd3Cu6L16 can be achieved by varying the reaction conditions. These capsules are able to selectively encapsulate tetrahedral anions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A new natural zircon reference material SA01 is introduced for U‐Pb geochronology as well as O and Hf isotope geochemistry by microbeam techniques. The zircon megacryst is homogeneous with respect to ...U‐Pb, O and Hf isotopes based on a large number of measurements by laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) and secondary ion mass spectrometry (SIMS). Chemical abrasion isotope dilution thermal ionisation mass spectrometry (CA‐ID‐TIMS) U‐Pb isotopic analyses produced a mean 206Pb/238U age of 535.08 ± 0.32 Ma (2s, n = 10). Results of SIMS and LA‐ICP‐MS analyses on individual shards are consistent with the TIMS ages within uncertainty. The δ18O value determined by laser fluorination is 6.16 ± 0.26‰ (2s, n = 14), and the mean 176Hf/177Hf ratio determined by solution MC‐ICP‐MS is 0.282293 ± 0.000007 (2s, n = 30), which are in good agreement with the statistical mean of microbeam analyses. The megacryst is characterised by significant localised variations in Th/U ratio (0.328–4.269) and Li isotopic ratio (−5.5 to +7.9‰); the latter makes it unsuitable as a lithium isotope reference material.
Keypoints
The homogeneity of the SA01 zircon megacryst was assessed by microbeam techniques for U‐Pb geochronology, and Li, O and Hf isotope geochemistry.
SA01 is homogeneous in terms of U‐Pb, O and Hf isotopes.
SA01 is unsuitable as a lithium isotope reference material.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Mucosal-associated invariant T (MAIT) cells have important functions in immune responses against pathogens and in diseases, but mechanisms controlling MAIT cell development and effector lineage ...differentiation remain unclear. Here, we report that IL-2/IL-15 receptor β chain and inducible costimulatory (ICOS) not only serve as lineage-specific markers for IFN-γ-producing MAIT1 and IL-17A-producing MAIT17 cells, but are also important for their differentiation, respectively. Both IL-2 and IL-15 induce mTOR activation, T-bet upregulation, and subsequent MAIT cell, especially MAIT1 cell, expansion. By contrast, IL-1β induces more MAIT17 than MAIT1 cells, while IL-23 alone promotes MAIT17 cell proliferation and survival, but synergizes with IL-1β to induce strong MAIT17 cell expansion in an mTOR-dependent manner. Moreover, mTOR is dispensable for early MAIT cell development, yet pivotal for MAIT cell effector differentiation. Our results thus show that mTORC2 integrates signals from ICOS and IL-1βR/IL-23R to exert a crucial role for MAIT17 differentiation, while the IL-2/IL-15R-mTORC1-T-bet axis ensures MAIT1 differentiation.
Coronavirus disease 2019 (COVID-19) is a novel and lethal infectious disease, posing a threat to global health security. The number of cases has increased rapidly, but no data concerning kidney ...transplant (KTx) recipients infected with COVID-19 are available. To present the epidemiological, clinical, and therapeutic characteristics of KTx recipients infected with COVID-19, we report on a case series of five patients who were confirmed as having COVID-19 through nucleic acid testing (NAT) from January 1, 2020 to February 28, 2020. The most common symptoms on admission to hospital were fever (five patients, 100%), cough (five patients, 100%), myalgia or fatigue (three patients, 60%), and sputum production (three patients, 60%); serum creatinine or urea nitrogen levels were slightly higher than those before symptom onset. Four patients received a reduced dose of maintenance immunosuppressive therapy during hospitalization. As of March 4, 2020 NAT was negative for COVID-19 in three patients twice in succession, and their computed tomography scans showed improved images. Although greater patient numbers and long-term follow-up data are needed, our series demonstrates that mild COVID-19 infection in KTx recipients can be managed using symptomatic support therapy combined with adjusted maintenance immunosuppressive therapy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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