Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 333
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Nature ; 622(7984): 754-760, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37730999

RESUMEN

Single-atom catalysts (SACs) have well-defined active sites, making them of potential interest for organic synthesis1-4. However, the architecture of these mononuclear metal species stabilized on solid supports may not be optimal for catalysing complex molecular transformations owing to restricted spatial environment and electronic quantum states5,6. Here we report a class of heterogeneous geminal-atom catalysts (GACs), which pair single-atom sites in specific coordination and spatial proximity. Regularly separated nitrogen anchoring groups with delocalized π-bonding nature in a polymeric carbon nitride (PCN) host7 permit the coordination of Cu geminal sites with a ground-state separation of about 4 Å at high metal density8. The adaptable coordination of individual Cu sites in GACs enables a cooperative bridge-coupling pathway through dynamic Cu-Cu bonding for diverse C-X (X = C, N, O, S) cross-couplings with a low activation barrier. In situ characterization and quantum-theoretical studies show that such a dynamic process for cross-coupling is triggered by the adsorption of two different reactants at geminal metal sites, rendering homo-coupling unfeasible. These intrinsic advantages of GACs enable the assembly of heterocycles with several coordination sites, sterically congested scaffolds and pharmaceuticals with highly specific and stable activity. Scale-up experiments and translation to continuous flow suggest broad applicability for the manufacturing of fine chemicals.

2.
Virol J ; 21(1): 151, 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38965616

RESUMEN

BACKGROUND: The canine influenza virus (CIV) outbreak has garnered considerable attention as it poses a significant threat to dog health. During the H3N2 CIV evolution in beagles, the virus formed a new clade after 2019 and gradually became more adaptable to other mammals. Therefore, successfully elucidating the biological characteristics and constructing a canine influenza infection model is required for CIV characterization. METHODS: We performed genetic analyses to examine the biological characteristics and infection dynamics of CIV. RESULTS: The genotype of our H3N2 CIV strain (from 2019 in Shanghai) belonged to the 5.1 clade, which is now prevalent in China. Using MDCK cells, we investigated viral cytopathic effects. Virus size and morphology were observed using transmission electron microscopy. Beagles were also infected with 104, 105, and 106 50% egg-infectious doses (EID50). When compared with the other groups, the 106 EID50 group showed the most obvious clinical symptoms, the highest virus titers, and typical lung pathological changes. Our results suggested that the other two treatments caused mild clinical manifestations and pathological changes. Subsequently, CIV distribution in the 106 EID50 group was detected by hematoxylin and eosin (H&E) and immunofluorescence (IF) staining, which indicated that CIV primarily infected the lungs. CONCLUSIONS: The framework established in this study will guide further CIV prevention strategies.


Asunto(s)
Enfermedades de los Perros , Genotipo , Subtipo H3N2 del Virus de la Influenza A , Infecciones por Orthomyxoviridae , Animales , Perros , Subtipo H3N2 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/virología , Infecciones por Orthomyxoviridae/patología , Enfermedades de los Perros/virología , Células de Riñón Canino Madin Darby , China/epidemiología , Pulmón/virología , Pulmón/patología , Filogenia , Carga Viral , Modelos Animales de Enfermedad
3.
BMC Nurs ; 23(1): 256, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38649865

RESUMEN

BACKGROUND: Abusive supervision by the nurse manager significantly influences nurses' withholding voice about patient safety. The role of impression management motivation and speak up-related climate is crucial in understanding their connection. This study aimed to explore the relationship between abusive supervision, impression management motivation, speak up-related climate, and withholding voice about patient safety. METHODS: This cross-sectional study employed a convenience sampling method to recruit 419 clinical nurses from Taizhou Hospital, Zhejiang Province, China, between 1 November 2022 and 31 January 2023. The study adhered to the STROBE checklist. Abusive supervision and impression management motivation were assessed using the Chinese versions of the Abusive Supervision Scale and the Impression Management Motivation Scale, respectively. Withholding voice about patient safety and speak up-related climate were identified using the Chinese version of the Speaking Up about Patient Safety Questionnaire. RESULTS: Nurse leaders' abusive supervision (ß=0.40, p<0.01) and nurses' impression management motivation (ß=0.10, p<0.01) significantly and positively influenced nurses' withholding voice about patient safety. We introduced impression management motivation as a mediating variable, and the effect of abusive supervision on nurses' withholding voice decreased (ß from 0.40 to 0.38, p< 0.01). Nurses' speak up-related climate played a moderating role between abusive supervision and impression management motivation (ß= 0.24, p<0.05). CONCLUSIONS: Abusive supervision by nursing leaders can result in nurses withholding voice about patient safety out of self-protective impression management motives. This phenomenon inhibits nurses' subjective initiative and undermines their proactive involvement in improving patient safety, and hinders the cultivation of a culture encouraging full participation in patient safety, which should warrant significant attention.

4.
Rep Prog Phys ; 86(10)2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37706242

RESUMEN

The concept of topological energy bands and their manifestations have been demonstrated in condensed matter systems as a fantastic paradigm toward unprecedented physical phenomena and properties that are robust against disorders. Recent years, this paradigm was extended to phononic metamaterials (including mechanical and acoustic metamaterials), giving rise to the discovery of remarkable phenomena that were not observed elsewhere thanks to the extraordinary controllability and tunability of phononic metamaterials as well as versatile measuring techniques. These phenomena include, but not limited to, topological negative refraction, topological 'sasers' (i.e. the phononic analog of lasers), higher-order topological insulating states, non-Abelian topological phases, higher-order Weyl semimetal phases, Majorana-like modes in Dirac vortex structures and fragile topological phases with spectral flows. Here we review the developments in the field of topological phononic metamaterials from both theoretical and experimental perspectives with emphasis on the underlying physics principles. To give a broad view of topological phononics, we also discuss the synergy with non-Hermitian effects and cover topics including synthetic dimensions, artificial gauge fields, Floquet topological acoustics, bulk topological transport, topological pumping, and topological active matters as well as potential applications, materials fabrications and measurements of topological phononic metamaterials. Finally, we discuss the challenges, opportunities and future developments in this intriguing field and its potential impact on physics and materials science.

5.
Opt Express ; 31(11): 17695-17708, 2023 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-37381496

RESUMEN

We systematically study the first- and second-order band topologies, which are tied to the pseudospin and valley degree of freedoms (DOFs), in honeycomb-kagome photonic crystals (HKPCs). We first demonstrate the quantum spin Hall phase as the first-order pseudospin-induced topology in HKPCs by observing the partial pseudospin-momentum locked edge states. By employing the topological crystalline index, we also discover the multiple corner states emerging in the hexagon-shaped supercell as the manifestation of the second-order pseudospin-induced topology in HKPCs. Next, by gapping the Dirac points, a lower band gap associated with the valley DOF emerges, in which the valley-momentum locked edge states are observed as the first-order valley-induced topology. Such HKPCs without inversion symmetry are proved to be Wannier-type second-order topological insulators, which manifested with valley-selective corner states. Additionally, we also discuss the symmetry breaking effect on pseudospin-momentum locked edge states. Our work realizes both pseudospin-induced and valley-induced topologies in a higher-order manner and thus provides more flexibility in manipulating electromagnetic waves, which may find potential applications in topological routings.

6.
Acta Radiol ; 64(2): 732-740, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35345899

RESUMEN

BACKGROUND: Intracranial atherosclerotic stenosis is a major cause of ischemic stroke, accounting for 30% of ischemic strokes in Asian populations. PURPOSE: To investigate the relationship between the degree of arterial stenosis and enhancement grade of intracranial atherosclerotic disease (ICAD), the plaque characteristics in different remodeling patterns, and its potential impact. MATERIAL AND METHODS: A total of 210 patients diagnosed with ICAD were enrolled in this retrospective study. Patients were divided into the middle cerebral artery (MCA) group (101 cases), posterior cerebral artery (PCA) group (14 cases), basilar artery (BA) group (71 cases), and intracranial segment of vertebral artery (VA) group (90 cases) according to the difference of diseased vessels. Data on presence or absence of ischemic infarction, intracranial vascular position of lesions, plaque characteristics, ICAD enhancement grade, remodeling index, and degree of arterial stenosis were collected for analysis. RESULTS: The incidence of ischemic infarction in enhancement grade 2 was significantly higher than that in enhancement grade 1 in MCA group (P = 0.019). Enhancement grade 2 of ICAD was an independent risk factor for the development of ischemic infarction (odds ratio = 4.60; 95% confidence interval: 1.91-11.03; P = 0.001). There was no significant statistical difference in infarct rate between different remodeling modalities (P>0.05). CONCLUSION: Enhancement grade of ICAD is significantly associated with the degree of stenosis and the occurrence of ischemic stroke, which varies in different intracranial vessels. The pattern of vascular remodeling varies among different intracranial vessels, and the pattern of vascular remodeling has a significant impact on plaque characteristics.


Asunto(s)
Aterosclerosis , Arteriosclerosis Intracraneal , Accidente Cerebrovascular Isquémico , Placa Aterosclerótica , Accidente Cerebrovascular , Humanos , Estudios Retrospectivos , Constricción Patológica , Remodelación Vascular , Imagen por Resonancia Magnética/efectos adversos , Angiografía por Resonancia Magnética , Placa Aterosclerótica/complicaciones , Placa Aterosclerótica/diagnóstico por imagen , Aterosclerosis/complicaciones , Infarto/complicaciones , Arteriosclerosis Intracraneal/complicaciones , Arteriosclerosis Intracraneal/diagnóstico por imagen , Accidente Cerebrovascular/complicaciones
7.
Nat Mater ; 20(6): 794-799, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33859382

RESUMEN

Weyl semimetals (WSMs)1 exhibit phenomena such as Fermi arc surface states, pseudo-gauge fields and quantum anomalies that arise from topological band degeneracy in crystalline solids for electrons1 and metamaterials for photons2 and phonons3. Here we report a higher-order Weyl semimetal (HOWSM) in a phononic system that exhibits topologically protected boundary states in multiple dimensions. We created the physical realization of the HOWSM in a chiral phononic crystal with uniaxial screw symmetry. Using acoustic pump-probe spectroscopies, we observed coexisting chiral Fermi arc states on two-dimensional surfaces and dispersive hinge arc states on one-dimensional hinge boundaries. These topological boundary states link the projections of the Weyl points (WPs) in different dimensions and directions, and hence demonstrate the higher-order topological physics4-8 in WSMs. Our study further establishes the fundamental connection between higher-order topology and Weyl physics in crystalline materials and should stimulate further work on other potential materials, such as higher-order topological nodal-line semimetals.

8.
Nat Mater ; 20(2): 181-187, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33106649

RESUMEN

Two-dimensional superconductor (2DSC) monolayers with non-centrosymmetry exhibit unconventional Ising pair superconductivity and an enhanced upper critical field beyond the Pauli paramagnetic limit, driving intense research interest. However, they are often susceptible to structural disorder and environmental oxidation, which destroy electronic coherence and provide technical challenges in the creation of artificial van der Waals heterostructures (vdWHs) for devices. Herein, we report a general and scalable synthesis of highly crystalline 2DSC monolayers via a mild electrochemical exfoliation method using flexible organic ammonium cations solvated with neutral solvent molecules as co-intercalants. Using NbSe2 as a model system, we achieved a high yield (>75%) of large-sized single-crystal monolayers up to 300 µm. The as-fabricated, twisted NbSe2 vdWHs demonstrate high stability, good interfacial properties and a critical current that is modulated by magnetic field when one flux quantum fits to an integer number of moiré cells. Additionally, formulated 2DSC inks can be exploited to fabricate wafer-scale 2D superconducting wire arrays and three-dimensional superconducting composites with desirable morphologies.

9.
Opt Express ; 30(10): 17204-17220, 2022 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-36221548

RESUMEN

The simulation of fermionic relativistic physics, e.g., Dirac and Weyl physics, has led to the discovery of many unprecedented phenomena in photonics, of which the optical-frequency realization is, however, still challenging. Here, surprisingly, we discover that the woodpile photonic crystals commonly used for optical frequency applications host exotic fermion-like relativistic degeneracies: a Dirac nodal line and a fourfold quadratic point, as protected by the nonsymmorphic crystalline symmetry. Deforming the woodpile photonic crystal leads to the emergence of type-II Dirac points from the fourfold quadratic point. Such type-II Dirac points can be detected by its anomalous refraction property which is manifested as a giant birefringence in a slab setup. Our findings provide a promising route towards 3D optical Dirac physics in all-dielectric photonic crystals.

10.
Opt Lett ; 47(6): 1454-1457, 2022 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-35290337

RESUMEN

The recent advancements in higher-order topology have provided unprecedented opportunities in optical device designs and applications. Here, we propose a new, to the best of our knowledge, method to realize rainbow trapping based on higher-order topological corner modes (HOTCMs), which are constructed by two configurations of breathing kagome photonic crystals with distinct topological phases. Interestingly, the HOTCMs localized at corners with different geometric configurations are found to be frequency dispersive and thus initiate the possible application in realizing rainbow trapping. By designing a polygon structure containing several configurations of corners, we demonstrate that the HOTCMs can be excited with the frequency sequence locked to the corner order (clockwise/anticlockwise direction) in the polygon. The reported HOTCMs provide a new mechanism to realize multiple-frequency trapping, which may find potential applications in future integrated photonics.

11.
J Comput Assist Tomogr ; 46(4): 645-650, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35675665

RESUMEN

BACKGROUND: The persistent trigeminal artery (PTA) is the most common remnant of primitive circulation, communicating the developing carotid and vertebrobasilar junction. PURPOSE: This study aimed to evaluate the implementation of magnetic resonance angiography for the detection of PTA and to reclassify the variations based on Weon typing. Moreover, the correlation of various Weon types with the posterior cerebral artery (PCA), Willis ring, basilar artery (BA) dysplasia, and the relationship between PTA and arteriosclerosis were analyzed. METHODS: From November 2017 to October 2019, a total of 48,184 patients underwent magnetic resonance angiography examination in our hospital, and 79 patients were diagnosed with PTA. Of these, 70 patients with complete radiological and clinical information were included in this study. RESULTS: Among the 70 patients with complete data, 27 were classified as Weon type I (38.6%), 7 as type II (10%), 14 as type III (20%), 8 as type IV (11.4%), and 3 as type V (4.3%: type Va, 1 case; type Vb, 2 cases). The remaining 11 cases were PCA with mixed blood supply, so the new type VI was divided into 3 subtypes: type VIa, type VIb, and type VIc, and each subtype of type V was further refined into 4 subtypes. There were 32 cases of PTA with BA dysplasia, including 14 with type I (51.9%), 5 with type II (71.4%), 2 with type III (14.3%), 5 with type IV (62.5%), and 6 with type VI (54.5%). Cerebral infarction was found in 55 cases (78.6%) of PTA, among which 11 had a cerebral infarction in the posterior circulation blood supply area. There were 46 cases (65.7%) accompanied by intracranial arteriosclerosis, and in 6 cases, arteriosclerosis mainly occurred in the posterior circulation. CONCLUSIONS: We redefined the classification of PTA based on Weon typing for a better understanding of clinical symptoms and surgical risks. Moreover, PTA was correlated with the fetal origin of PCA, BA dysplasia, and posterior circulation arteriosclerosis. These factors may increase the incidence of cerebral infarction in the posterior circulation blood supply area.


Asunto(s)
Arteria Basilar , Angiografía por Resonancia Magnética , Arteria Basilar/diagnóstico por imagen , Infarto Cerebral , Humanos , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética
12.
J Nanobiotechnology ; 20(1): 220, 2022 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-36310171

RESUMEN

BACKGROUND: Glucocorticoids (GCs) overuse is associated with decreased bone mass and osseous vasculature destruction, leading to severe osteoporosis. Platelet lysates (PL) as a pool of growth factors (GFs) were widely used in local bone repair by its potent pro-regeneration and pro-angiogenesis. However, it is still seldom applied for treating systemic osteopathia due to the lack of a suitable delivery strategy. The non-targeted distribution of GFs might cause tumorigenesis in other organs. RESULTS: In this study, PL-derived exosomes (PL-exo) were isolated to enrich the platelet-derived GFs, followed by conjugating with alendronate (ALN) grafted PEGylated phospholipid (DSPE-PEG-ALN) to establish a bone-targeting PL-exo (PL-exo-ALN). The in vitro hydroxyapatite binding affinity and in vivo bone targeting aggregation of PL-exo were significantly enhanced after ALN modification. Besides directly modulating the osteogenic and angiogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and endothelial progenitor cells (EPCs), respectively, PL-exo-ALN also facilitate their coupling under GCs' stimulation. Additionally, intravenous injection of PL-exo-ALN could successfully rescue GCs induced osteoporosis (GIOP) in vivo. CONCLUSIONS: PL-exo-ALN may be utilized as a novel nanoplatform for precise infusion of GFs to bone sites and exerts promising therapeutic potential for GIOP.


Asunto(s)
Exosomas , Células Madre Mesenquimatosas , Osteoporosis , Humanos , Exosomas/metabolismo , Glucocorticoides/metabolismo , Células Madre Mesenquimatosas/metabolismo , Osteogénesis , Osteoporosis/inducido químicamente , Osteoporosis/tratamiento farmacológico , Alendronato/farmacología
13.
Neurol Sci ; 43(9): 5421-5430, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35616814

RESUMEN

OBJECTIVE: To investigate the etiology of intracranial artery stenosis and the distribution characteristics of intracranial artery atherosclerotic stenosis using high-resolution magnetic resonance imaging (HR-MRI). METHODS: A total of 262 patients with intracranial artery stenosis that underwent HR-MRI from November 2019 to December 2020 were retrospectively enrolled. The etiology of intracranial anterior and posterior circulation artery stenosis was analyzed, and the relationship between the location of plaques and the distribution characteristics of plaques and the occurrence of ischemic stroke was summarized. RESULTS: A total of 276 plaques were identified with HR-MRI. There were 101 cases (36.59%) in the middle cerebral artery (MCA), 14 cases (5.07%) in the posterior cerebral artery (PCA), 90 cases (32.62%) in vertebral artery (VA), and 71 cases (25.72%) in the basilar artery (BA). The infarct rate of ventral and superior wall MCA plaques was higher than that of dorsal and inferior wall (63.33% vs 31.25% P = 0.021) (100.00% vs 50% P = 0.022). MCA with plaques throughout the course had the greatest degree of stenosis (P < 0.001). Sphenoid segment (M1) of MCA was most susceptible (85 cases, 84.16%), MCA plaques were most common in the proximal M1 segment (35 cases, 34.65%), and most BA plaques were found in the distal segment (28 cases, 39.44%). PCA plaques were most frequently involved in traffic anterior segment (P1) (7 cases, 50.00%). CONCLUSION: HR-MRI could provide accurate imaging reference for clinical evaluation of intracranial arterial stenosis and formulation of treatment plans. The intracranial arterial plates mostly appeared in the middle cerebral artery and vertebral artery. Middle cerebral arteries with atherosclerotic plaques are more likely to narrow.


Asunto(s)
Arteriosclerosis Intracraneal , Placa Aterosclerótica , Constricción Patológica/diagnóstico por imagen , Humanos , Arteriosclerosis Intracraneal/diagnóstico por imagen , Angiografía por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/métodos , Arteria Cerebral Media/diagnóstico por imagen , Arteria Cerebral Media/patología , Placa Aterosclerótica/diagnóstico por imagen , Placa Aterosclerótica/patología , Estudios Retrospectivos
14.
J Clin Microbiol ; 59(2)2021 01 21.
Artículo en Inglés | MEDLINE | ID: mdl-33177126

RESUMEN

In February and December of 2019, two large-scale outbreaks of diarrhea were observed in the same swine farm with 3,000 sows in Shanghai, China. We successfully isolated two porcine epidemic diarrhea virus (PEDV) isolates (strains shxx1902 and shxx1912 in February and December, respectively) from clinical samples in this farm using suspension Vero cells. A third PEDV strain (SH1302) tested positive in another farm of Shanghai, China, in 2013 and was also isolated using suspension Vero cells. The three isolates were better adapted to growth in adherent Vero cells through serial passages in the suspension Vero cells. The three isolated strains were detected positive by an immunofluorescence assay (IFA) and observed through electron microscopy. Phylogenetic analysis of the complete genomic sequence demonstrated that shxx1902 (the 5th passage) and shxx1912 (the 5th passage) clustered with a new GII subgroup (GII-c), which consisted of SINDEL strains from America (e.g., OH851), and their S gene belonged to GII-a. Both strains(the 35th passage) have incurred dramatic changes in their genomes compared with the 5th passage. The 5th and 35th passages of SH1302 belonged to the GI-b genotype. The anti-N protein antibody titer of the strain shxx1902 was elevated to the same level as the vaccine strain (CV777) in mice. The use of the suspension Vero cells to isolate and propagate PEDV provides an effective approach for studies of the epidemiological characteristics and vaccine development of this virus.


Asunto(s)
Infecciones por Coronavirus , Virus de la Diarrea Epidémica Porcina , Enfermedades de los Porcinos , Animales , China/epidemiología , Chlorocebus aethiops , Femenino , Ratones , Filogenia , Virus de la Diarrea Epidémica Porcina/genética , Porcinos , Células Vero
15.
J Med Virol ; 93(6): 3496-3507, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33386745

RESUMEN

H3N2 feline influenza virus (FIV) and canine influenza virus (CIV) are very common in cats and dogs. Due to the ability of the influenza virus to spread across hosts and frequent contact between pets and people, there exist huge public health problems. In this study, we collected H3N2 CIV and FIV genomes from 2006 to 2019 from NCBI and analyzed the evolutionary dynamics and molecular variation using a series of phylogenetic analysis methods. Results indicated that H3N2 FIVs were closely related to CIVs with high posterior probability and CIVs and FIVs have certain regional characteristics. However, compared with previous studies, the significance of geographical structure correlation decreased. Furthermore, we also found that the intrasubtypic reassortment between FIVs and CIVs were common during epidemics. The integrated analysis was also performed for different selection pressure acting on HA (566 codons), NA (469 codons), M1 (252 codons), and M2 (97 codons) proteins. One HA, two NA, three M1, and two M2 sites were found under positive selection. We subsequently performed the evolutionary dynamics of H3N2 CIV. The results indicated that the time of the most recent common ancestor of CIV H3N2 may have occurred earlier than indicated in a previous study. The Bayesian skyline plot analysis in this study showed the period of divergence of major H3N2 CIVs segments occurred between 2008 and 2010. Notably, according to our research, the PB1 has experienced two divergence periods (2006-2008 and 2009-2011).


Asunto(s)
Evolución Molecular , Subtipo H3N2 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/veterinaria , Infecciones por Orthomyxoviridae/virología , Filogenia , Animales , Teorema de Bayes , Enfermedades de los Gatos/virología , Gatos , Enfermedades de los Perros/virología , Perros , Genoma Viral , Selección Genética
16.
Opt Express ; 29(24): 40606-40616, 2021 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-34809396

RESUMEN

We proposed an one-dimensional layer-stacked photonic crystal using anisotropic materials to realize ideal type-II Weyl points. The topological transition from Dirac to Weyl points can be clearly observed by tuning the twist angle between layers. Also, on the interface between the photonic type-II Weyl material and air, gapless surface states have been demonstrated in an incomplete bulk bandgap. By breaking parameter symmetry, these ideal type-II Weyl points would transform into the non-ideal ones, exhibiting topological surface states with single group velocity. Our work may provide a new idea for the realization of photonic semimetal phases by utilizing naturally anisotropic materials.

17.
Neoplasma ; 68(5): 1098-1106, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34156257

RESUMEN

Multiple endocrine neoplasia type 2A (MEN2A) is a rare syndrome caused almost by germline RET mutation, and characterized by medullary thyroid carcinoma (MTC), in combination or not with pheochromocytoma (PHEO), hyperparathyroidism (HPTH), cutaneous lichen amyloidosis (CLA), and Hirschsprung's disease (HD). The basal serum calcitonin (Ctn)/carcinoembryonic antigen (CEA) levels are significantly correlated with the MTC stage. Metachronous surgery of MEN2A-specific tumors is a routine procedure. We aimed to explore the clinical significance of pro-gastrin-releasing peptide (proGRP) in MTC with elevated Ctn and simultaneous surgery of MEN2A-specific tumors. We retrospectively investigated 8 RET mutation carriers of 2 Chinese pedigrees with MEN2A. Clinical profiles, imaging examinations, preoperative and postoperative biochemical data, surgical procedures, and follow-up records were evaluated. Three patients showed levels of elevated Ctn but normal proGRP. Among them, one patient (FAIII-6) in Family A (one for RET C634R mutation), diagnosed with bilateral MTC, left PHEO, bilateral HPTH, and CLA, classified as MEN2A-related CLA subtype, underwent successfully simultaneous adrenal-sparing surgery (ASS), total thyroidectomy (TT), and parathyroidectomy, while TT of the other two patients (FBII-3 and FBIII-7) diagnosed with bilateral MTC in Family B (all for RET C618R mutation) were performed. Unexpectedly, the absence of neck lymph node MTC metastasis was indicated by histopathological examination. Postoperatively, all had consistently "undetectable" or normal levels of Ctn/CEA during follow-up. Patients with normal proGRP, despite high levels of Ctn, might have no regional lymph node MTC metastasis, and neck dissection should be avoided. Moreover, simultaneous surgery for coexistent PHEO and either MTC or HPTH is an approach of choice to use as an alternative treatment pattern. Recognition of MEN2A-related CLA and subsequently early screening of RET mutation may be favorable for timely management of MEN2A-specific tumors.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales , Neoplasia Endocrina Múltiple Tipo 2a , Neoplasias de la Tiroides , Calcitonina , Humanos , Neoplasia Endocrina Múltiple Tipo 2a/genética , Neoplasia Endocrina Múltiple Tipo 2a/cirugía , Proteínas Proto-Oncogénicas c-ret/genética , Estudios Retrospectivos , Neoplasias de la Tiroides/genética , Neoplasias de la Tiroides/cirugía
18.
BMC Surg ; 21(1): 210, 2021 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-33902538

RESUMEN

BACKGROUND: Adrenal hemangioma is a rare benign adrenal tumor that is usually misdiagnosed preoperatively. We here present a case of adrenal cavernous hemangioma that was successfully treated with retroperitoneal laparoscopic adrenalectomy. CASE PRESENTATION: A 67-year-old man with dull right back pain attended our clinic for examination of a mass on the right adrenal gland for 1 week. Pheochromocytoma was considered according to the preoperative computed tomography angiography + computed tomography urography findings and was subsequently corrected to adrenal gland hemangioma according to postoperative pathological findings. The patient showed no recurrence of adrenal hemangioma during the 1-year follow-up period after surgery. CONCLUSION: Adrenal gland hemangioma is rare with a high rate of misdiagnosis, and it should be considered in imaging findings of adrenal tumors with typical hemangioma. Surgery is an effective treatment method.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales , Hemangioma Cavernoso , Feocromocitoma , Neoplasias de las Glándulas Suprarrenales/diagnóstico , Neoplasias de las Glándulas Suprarrenales/cirugía , Anciano , Errores Diagnósticos , Hemangioma Cavernoso/diagnóstico por imagen , Hemangioma Cavernoso/cirugía , Humanos , Masculino , Recurrencia Local de Neoplasia , Feocromocitoma/diagnóstico por imagen , Feocromocitoma/cirugía
19.
Phys Rev Lett ; 125(14): 146401, 2020 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-33064542

RESUMEN

Higher-order topology yields intriguing multidimensional topological phenomena, while Weyl semimetals have unconventional properties such as chiral anomaly. However, so far, Weyl physics remain disconnected with higher-order topology. Here, we report the theoretical discovery of higher-order Weyl semimetals and thereby the establishment of such an important connection. We demonstrate that higher-order Weyl semimetals can emerge in chiral materials such as chiral tetragonal crystals as the intermediate phase between the conventional Weyl semimetal and 3D higher-order topological phases. Higher-order Weyl semimetals manifest themselves uniquely by exhibiting concurrent chiral Fermi-arc surface states, topological hinge states, and the momentum-dependent fractional hinge charge, revealing a novel class of higher-order topological phases.

20.
Virus Genes ; 56(3): 329-338, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32107672

RESUMEN

An avian-origin canine influenza virus (CIV) has recently emerged in dogs and is spreading in China. Given that humans have frequent contact with dogs, this has prompted an increased emphasis on biosafety. In this study, we collected 693 nasal swab samples and 800 blood samples from stray dogs in animal shelters to survey canine influenza epidemiology and characterize the evolution of CIV H3N2 in Shanghai. We tested samples for canine influenza antibodies and canine influenza RNA in January-May, 2019, and the results showed that the positive rate was 17.62% by ELISA, 15.75% by microneutralization (MN) assay, and 18.51% by real time RT-PCR, respectively. We also performed phylogenetic and genomic analysis on six H3N2 CIV isolates. The H3N2 viruses which prevailed in Shanghai originated from Beijing and Jiangsu isolates. Phylogenetic analysis showed that the sequences of CIV isolates have multiple amino acid antigenic drifts, deletions, and substitutions. The time of the most recent common ancestor (TMRCA) of HA and NA was 2004 and 2005, respectively. Notably, the substitution, 146S, in hemagglutinin and the deletion in the neuraminidase (NA) stalk region we found in this study warrant attention because they have frequently been identified in human influenza viruses. The potential adaptation of this CIV H3N2 clade to mammals and its public health threat should be further evaluated.


Asunto(s)
Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/virología , Evolución Molecular , Subtipo H3N2 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/veterinaria , Animales , China/epidemiología , Perros , Genes Virales , Subtipo H3N2 del Virus de la Influenza A/clasificación , Filogenia , Vigilancia en Salud Pública , ARN Viral
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA