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1.
Artigo em Inglês | MEDLINE | ID: mdl-38736090

RESUMO

BACKGROUND: The aim of this study was to evaluate factors to predict positive peritoneal cytology, whcih would determine the indication for staging laparoscopy in pancreatic cancer. METHODS: A total of 430 patients that underwent pancreatectomy for resectable and borderline resectable pancreatic cancer were retrospectively reviewed. RESULTS: Among 430 patients, 36 had positive cytology (8.4%). Median survival time in negative cytology was 24.7 months, compared with 15.1 months in positive cytology (p = .004). Factors to predict positive cytology in pancreatic cancer according to multivariate analysis were tumor location (body, tail; OR 2.66; 95% CI: 1.21-5.85; p = .015), tumor size ≥30 mm (OR 2.95; 95% CI: 1.35-6.47; p = .007) and radiographic other-organ invasion (HR 2.79; 95% CI: 1.01-7.67; p = .047). Patients were scored 0 to 3 corresponding with these factors. Rates of positive cytology increases in each score were: score 0: 2.9%, score 1: 6.7%, score 2: 18.3%, score 3: 36.8%. CONCLUSIONS: Tumor location (body or tail), tumor size ≥30 mm, and radiographic other-organ invasions were risk factors for positive cytology in pancreatic cancer. This scoring system might be a useful indicator to perform staging laparoscopy to diagnose positive cytology.

2.
Phys Rev Lett ; 132(13): 136401, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38613277

RESUMO

A striking feature of non-Hermitian systems is the presence of two different types of topology. One generalizes Hermitian topological phases, and the other is intrinsic to non-Hermitian systems, which are called line-gap topology and point-gap topology, respectively. Whereas the bulk-boundary correspondence is a fundamental principle in the former topology, its role in the latter has not been clear yet. This Letter establishes the bulk-boundary correspondence in the point-gap topology in non-Hermitian systems. After revealing the requirement for point-gap topology in the open boundary conditions, we clarify that the bulk point-gap topology in open boundary conditions can be different from that in periodic boundary conditions. On the basis of real space topological invariants and the K theory, we give a complete classification of the open boundary point-gap topology with symmetry and show that the nontrivial open boundary topology results in robust and exotic surface states.

3.
J Cancer Res Clin Oncol ; 150(2): 35, 2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38277079

RESUMO

PURPOSE: We investigated the potential clinical utility of short-term serial KRAS-mutated circulating cell-free tumor DNA (ctDNA) assessment for predicting therapeutic response in patients undergoing first-line chemotherapy for advanced pancreatic cancer. METHODS: We collected 144 blood samples from 18 patients with locally advanced or metastatic cancer that were undergoing initial first-line chemotherapy of gemcitabine plus nab-paclitaxel (GEM plus nab-PTX). Analysis of KRAS-mutated ctDNA was quantified by digital droplet polymerase chain reaction (ddPCR) as mutant allele frequency (MAF). This study investigated pretreatment KRAS-mutated ctDNA status and ctDNA kinetics every few days (days 1, 3, 5 and 7) after initiation of chemotherapy and their potential as predictive indicators. RESULTS: Of the 18 enrolled patients, an increase in KRAS-mutated ctDNA MAF values from day 0-7 after initiation of chemotherapy was significantly associated with disease progression (P < 0.001). Meanwhile, positive pretreatment ctDNA status (MAF ≥ 0.02%) (P = 0.585) and carbohydrate antigen 19-9 (CA19-9) values above the median (P = 0.266) were not associated with disease progression. In univariate analysis, this short-term increase in ctDNA MAF values (day 0-7) was found to be associated with significantly shorter progression free survival (PFS) (hazard ration [HR], 24.234; range, (2.761-212.686); P = 0.0002). CONCLUSION: This short-term ctDNA kinetics assessment may provide predictive information to reflect real-time therapeutic response and lead to effective refinement of regimen in patients with advanced pancreatic cancer undergoing systemic chemotherapy.


Assuntos
Ácidos Nucleicos Livres , DNA Tumoral Circulante , Neoplasias Pancreáticas , Humanos , DNA Tumoral Circulante/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Progressão da Doença , Intervalo Livre de Progressão , Biomarcadores Tumorais/genética , Mutação , Prognóstico
4.
Eur J Surg Oncol ; 49(10): 106960, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37353425

RESUMO

BACKGROUND: The prognostic impact of radiographic duodenal invasion (rDI) of pancreatic ductal adenocarcinoma (PDAC) has yet to be fully elucidated. This retrospective study aimed to investigate the prognostic and clinicopathological significance of rDI in patients with PDAC after pancreatoduodenectomy (PD). MATERIALS AND METHODS: We retrospectively analyzed 223 consecutive patients with resectable (R) and borderline resectable (BR)-PDAC that underwent up-front PD between 2002 and 2018. rDI was assessed by preoperative multi-detector row computed tomography. RESULTS: Ninety-three (42%) patients with PDAC had rDI, and all of them had pathological DI (pDI). The rDI(+) group had larger tumor size, BR-PDAC was more common, there was higher serum CA19-9 level, and microscopic lymphovascular invasion was more common than in the rDI(-) group. rDI was associated with significant reduction in overall survival (OS) (P < 0.001) and recurrence-free survival (RFS) (P < 0.001). In multivariate analysis, rDI was an independent prognostic factor in OS [hazard ratio (HR) = 0.52; 95% confidence interval (CI) 0.38-0.73, P < 0.001] and RFS [HR = 0.56; 95% CI 0.40-0.78, P = 0.001]. rDI was also an independent risk factor for early recurrence within 12 months [odds ratio (OR) = 0.36; 95% CI 0.18-0.73, P = 0.005]. rDI had positive correlation with liver recurrence (P = 0.024). CONCLUSION: Biological aggressiveness of PDAC with rDI implies short OS and early recurrence with frequent liver metastasis. Aggressive perioperative chemotherapy is recommended to improve prognosis, especially for R-PDAC patients with rDI.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Estudos Retrospectivos , Recidiva Local de Neoplasia/patologia , Neoplasias Pancreáticas/diagnóstico por imagem , Neoplasias Pancreáticas/cirurgia , Neoplasias Pancreáticas/tratamento farmacológico , Carcinoma Ductal Pancreático/diagnóstico por imagem , Carcinoma Ductal Pancreático/cirurgia , Carcinoma Ductal Pancreático/tratamento farmacológico , Prognóstico , Neoplasias Pancreáticas
5.
Phys Rev Lett ; 131(25): 256602, 2023 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-38181366

RESUMO

Whereas point-gap topological phases are responsible for exceptional phenomena intrinsic to non-Hermitian systems, their realization in quantum materials is still elusive. Here, we propose a simple and universal platform of point-gap topological phases constructed from Hermitian topological insulators and superconductors. We show that (d-1)-dimensional point-gap topological phases are realized by making a boundary in d-dimensional topological insulators and superconductors dissipative. A crucial observation of the proposal is that adding a decay constant to boundary modes in d-dimensional topological insulators and superconductors is topologically equivalent to attaching a (d-1)-dimensional point-gap topological phase to the boundary. We furthermore establish the proposal from the extended version of the Nielsen-Ninomiya theorem, relating dissipative gapless modes to point-gap topological numbers. From the bulk-boundary correspondence of the point-gap topological phases, the resultant point-gap topological phases exhibit exceptional boundary states or in-gap higher-order non-Hermitian skin effects.

6.
Heliyon ; 8(11): e11585, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36406716

RESUMO

Aeromonas spp., widely present in rivers and soil, cause mild gastroenteritis, severe septicemia, and soft tissue infections in humans. Treatment of these infections require accurate identification of pathogenic Aeromonas spp. However, identification at the species level using conventional methods is highly challenging. In this study, we aimed to compare the accuracy of two different approaches developed for bacterial identification: (i) housekeeping gene sequencing (rpoB) in conjunction with phylogenetic analysis and (ii) matrix-assisted laser desorption ionization mass spectrometry-time of flight (MALDI-TOF MS) (MALDI Biotyper and VITEK MS), for differentiating Aeromonas spp. We analyzed 58 Aeromonas isolates recovered from patients at different medical institutions in Japan using both identification methods. The rpoB sequencing method was the most accurate, identifying all Aeromonas isolates at the species level. Meanwhile, the MALDI Biotyper system correctly identified 53 (91.4%) isolates at the genus level and an additional 30 (51.7%) at the species level. The VITEK MS system correctly identified 58 (100%) isolates at the genus level and an additional 34 (58.6%) at the species level. Thus, MALDI Biotyper and VITEK MS accurately identified isolates at the genus level, but differences were found in the accuracy of identification of species. However, the low cost and ease of analysis make MALDI-TOF MS-based methods strong candidates for use in clinical laboratories that require easy-to-use identification methods.

7.
Front Psychol ; 13: 891452, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35572226

RESUMO

This study examined the relationships between teacher motivation (TM) and perceived burnout of English-as-a-foreign-language (EFL) teachers in Chile. A particular focus was given to demotivators and their impact on TM and burnout. The impact of COVID-19 was considered. Given that EFL teachers tend to be second language (L2) learners of English themselves, the study also investigated how TM and L2 motivation interact with each other. The participants were 154 school-level teachers with a range of backgrounds (teaching experience, geographic areas, and school sectors). In the questionnaire, four scales were included: (a) autonomous motivation for teaching; (b) demotivators; (c) perceived burnout; and (d) L2 motivation. Fifteen teachers were interviewed in order to triangulate the survey results. Structural equation modeling showed that TM negatively predicted perceived burnout, suggesting that it can counter teachers' emotional exhaustion and their perceived lack of personal accomplishment. Demotivators predicted TM positively, albeit weakly. L2 motivation was found to be only weakly related to TM. Qualitative findings indicated that teaching experience mediated the role that demotivators played in relation to TM. Experienced teachers, especially those who held intrinsic motivation to teach, channeled the impact of demotivators, including those relating to the pandemic, to a positive motivational force to teach. The study implies the importance of considering teachers as agents and devising an educational system in which their mental health is prioritized.

8.
Biomed Res ; 43(1): 11-22, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35173112

RESUMO

The epithelial basal lamina of the small intestine has numerous fenestrations for intraepithelial migration of leukocytes. We have reported dynamic changes of fenestrations in dietary conditions. To investigate this phenomenon, we performed statistical analyses using scanning electron microscopy images of the epithelial basal lamina of rat intestinal villi after removal of the villous epithelium by osmium maceration. We examined structural changes in the number and size of fenestrations in the rat jejunum and ileum under fasted and fed states for 24 h. Our findings revealed that, in the jejunum, the number of free cells migrating into the epithelium through fenestrations increased from 2 h after feeding, resulting in an increase in the fenestration size of intestinal villi; the number of free cells then tended to decrease at 6 h after feeding, and the fenestration size also gradually decreased. By contrast, the increase in the fenestration size by feeding was not statistically significant in the ileum. These findings indicate that the number of migrating cells increases in the upper part of the small intestine under dietary conditions, which may influence the absorption efficiency of nutrients including lipids, as well as the induction of nutrient-induced inflammation.


Assuntos
Mucosa Intestinal , Intestino Delgado , Animais , Membrana Basal , Dieta , Epitélio , Microscopia Eletrônica de Varredura , Ratos
9.
Phys Rev Lett ; 127(19): 196404, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34797152

RESUMO

The Nielsen-Ninomiya theorem is a fundamental theorem on the realization of chiral fermions in static lattice systems in high-energy and condensed matter physics. Here we extend the theorem in dynamical systems, which include the original Nielsen-Ninomiya theorem in the static limit. In contrast to the original theorem, which is a no-go theorem for bulk chiral fermions, the new theorem permits them due to bulk topology intrinsic to dynamical systems. The theorem is based on duality enabling a unified treatment of periodically driven systems and non-Hermitian ones. We also present the extended theorem for nonchiral gapless fermions protected by symmetry. Finally, as an application of our theorem and duality, we predict a new type of chiral magnetic effect-the non-Hermitian chiral magnetic skin effect.

10.
J Infect Chemother ; 27(12): 1689-1693, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34393040

RESUMO

INTRODUCTION: Vancomycin-resistant Enterococcus (VRE) is a rare bacterium in Japan, but an outbreak due to nosocomial transmission in medical facilities has been reported in recent years. Here, we report the outbreak of vanA vancomycin-resistant Enterococcus faecium (VREfm) in multiple wards of Nara Prefectural General Medical Center in 2019 and results of the molecular epidemiology analysis. METHODS: An aggressive screening program was conducted after the first VREfm was detected in a patient in the A ward. During the outbreak, 6000 rectal swab samples were screened for VRE by culture. Isolates from 60 patients with VREfm detected were clustered using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). RESULTS: PFGE revealed a cluster consisting of three major clusters and four multi-strains. The first major cluster consisted of 26 isolates, the second consisted of 10 isolates, the third consisted of 6 isolates, and the remaining 4 clusters consisted of 2 isolates. MLST identified an allele profile (ST80) in most clusters of clone types P01-P06 but an allele profile (ST992) in cluster P07. CONCLUSION: Based on the PFGE pattern, this case was considered to be a nosocomial infection due to multiple clones. Later, in addition to screening, sharing of hospital information, cohorting of patients and staff, and strengthening of environmental cleanup were carried out, and horizontal infection was suppressed.


Assuntos
Infecção Hospitalar , Enterococcus faecium , Infecções por Bactérias Gram-Positivas , Antibacterianos , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/epidemiologia , Enterococcus faecium/genética , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/epidemiologia , Hospitais Gerais , Humanos , Japão/epidemiologia , Epidemiologia Molecular , Tipagem de Sequências Multilocus , Vancomicina
11.
Biosci Microbiota Food Health ; 40(3): 150-155, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34285860

RESUMO

Sarcopenia causes functional disorders and decreases the quality of life. Thus, it has attracted substantial attention in the aging modern world. Dysbiosis of the intestinal microbiota is associated with sarcopenia; however, it remains unclear whether prebiotics change the microbiota composition and result in the subsequent recovery of muscle atrophy in elderly patients with sarcopenia. This study aimed to assess the effects of prebiotics in super-elderly patients with sarcopenia. We analyzed the effects of 1-kestose on the changes in the intestinal microbiota and body composition using a next-generation sequencer and a multi-frequency bioimpedance analysis device. The Bifidobacterium longum population was significantly increased in the intestine after 1-kestose administration. In addition, in all six patients after 12 weeks of 1-kestose administration, the skeletal muscle mass index was greater, and the body fat percentage was lower. This is the first study to show that administration of a prebiotic increased the population of B. longum in the intestinal microbiota and caused recovery of muscle atrophy in super-elderly patients with sarcopenia.

12.
Front Psychol ; 12: 641641, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34149525

RESUMO

Improving citizens' subjective well-being (SWB) has become an increasingly visible policy goal across industrialized countries. Although an increasing number of studies have investigated SWB at the individual level, little is known about subjective evaluation at social levels, such as the community and national levels. While the relationships between these levels have been analyzed in previous research, these assessments, which are part of the same unique construct of SWB, are under-investigated. The purpose of this study was to examine the dimensionality and reliability of a single measure of SWB, which contained individual, community, and national levels across three Latin-American countries (Argentina, Chile, and Venezuela), using a bifactor model analysis. Findings showed that the bifactor model exhibited a good fit to the data for the three countries. However, invariance testing between countries was not fully supported because of each item's specific contribution to both specific and general constructs. The analyses of each country showed that the SWB construct was in a gray area between unidimensionality and multidimensionality; some factors contributed more to the general factor and others to the specific level, depending on the country. These findings call for integrating more distant levels (community and country levels) into the understanding of SWB at the individual level, as they contribute not only to an overall construct, but they make unique contributions to SWB, which must be considered in public policy making.

13.
Phys Rev Lett ; 126(17): 176601, 2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33988440

RESUMO

There is a common belief in the condensed matter community that bulk quantities become insensitive to the boundary condition in the infinite-volume limit. Here we reconsider this statement in terms of recent arguments of non-Hermitian skin effects-strong dependence of spectra on boundary conditions for the non-Hermitian Hamiltonians-in the traditional Green's function formalism. We find the criterion for quantities to be sensitive or insensitive against the boundary condition in Hermitian correlated or disordered systems, which is characterized by the residue theorem. We also discuss the uncertainty of the quasiparticle energy under the skin effects in terms of non-normal pseudospectra, which can be tested via the sharp optical absorption from the bulk-surface coupling. Our result indicates that pseudo quantum number emerges as a consequence of large nonnormality.

14.
J Infect Chemother ; 27(6): 864-868, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33642249

RESUMO

INTRODUCTION: Knowledge is limited on the virologic course of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, particularly the time taken for viral clearance and the optimal time to discontinue isolation. This study aims to identify the clinical and demographic factors influencing the time taken for viral clearance in patients with COVID-19 to determine the optimal isolation period. METHODS: This two-center retrospective observational cohort study was conducted between March 1 and June 31, 2020. Patients with COVID-19, which was confirmed by real-time reverse transcription polymerase chain reaction, were included. Data were extracted from medical records. The positive duration, which was defined as the period from the day of symptom onset to the negative conversion day, was assessed using a generalized linear model. RESULTS: We included 63 patients. The mean positive duration was 20 days. The positive duration was significantly shorter for patients younger than 30 years of age and those between 30 and 60 years of age than for patients older than 60 years of age. We observed a more scattered distribution of the positive duration in older patients than in younger patients. CONCLUSIONS: Younger patients who recovered from COVID-19 took less time to clear SARS-CoV-2 than older patients; thus, a classification of the isolation periods based on age could be considered. A uniform viral clearance period for older patients may be difficult to determine because of biases such as underlying medical conditions. Further surveillance measures are recommended to determine the viral clearance time and the optimal isolation period.


Assuntos
COVID-19/diagnóstico , Isolamento de Pacientes , Carga Viral , Adulto , Idoso , Antagonistas de Receptores de Angiotensina , Inibidores da Enzima Conversora de Angiotensina , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19 , Feminino , Humanos , Hipertensão , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SARS-CoV-2
15.
J Infect Chemother ; 27(5): 740-746, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33386260

RESUMO

Bordetella trematum and Kerstersia gyiorum are rare gram-negative bacilli that are not frequently detected in human infections. In this report, we describe a case of a 48-year-old man who presented to our hospital with an infected wound on his leg. Discharges from the cracks of the granulation were collected and evaluated in our microbiology laboratory. Gram staining of the specimen showed polymorphonuclear leukocytes and abundant gram-negative bacilli. Three types of colonies were isolated on blood agar and were identified as B. trematum and Alcaligenes faecalis using VITEK MS. Moreover, K. gyiorum and B. trematum were identified and confirmed via 16S ribosomal RNA (rRNA) gene sequencing. The patient successfully recovered following application of meropenem antibacterial therapy and surgical debridement. This is the first reported case of complex wound infection caused by both B. trematum and K. gyiorum. Identification of B. trematum has recently been made possible by routine bacterial identification using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS). However, K. gyiorum isolation is still rare, and species identification requires 16S rRNA sequencing. Thus, this case highlighted the importance of using multiple methods, such as MALDI-TOF MS and 16S rRNA gene sequencing, for identification of rarely isolated species from clinical specimens.


Assuntos
Bordetella , Dermatite , Alcaligenaceae , Bordetella/genética , Humanos , Masculino , Pessoa de Meia-Idade , RNA Ribossômico 16S/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
16.
Data Brief ; 31: 106000, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32695861

RESUMO

The survey data derives from a newly-developed questionnaire of interaction mindset. Interaction mindset pertains to second language (L2) learners' disposition towards the task and/or an interlocutor prior to and/or during task-based interaction [1]. The theoretical model is consisted of five factors: (a) peer interaction; (b) collaboration; (c) form-orientation; (d) provision of peer feedback; and (e) reception of peer feedback. In the larger study ("Predicting L2 learners' noticing of L2 errors: Proficiency, language analytical ability, and interaction mindset" [2]), the questionnaire results were used as predictor variables of L2 learners' attention to language form. The current dataset contains responses from 102 L2 learners in university-level English classes. In addition to the descriptive statistics of the questionnaire, the current article reports on the results from structural equation modeling explaining the unique contributions of the five factors to the construct of interaction mindset. The model is visually depicted with a figure using AMOS. The model shows the questionnaire's potential in examining L2 learners' affective variables that may influence the learners' cognitive and behavioural engagement patterns. The entire dataset is included in an Excel file (.xlsx) and the original questionnaire is included as a supplementary file.

17.
Phys Rev Lett ; 124(8): 086801, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32167324

RESUMO

A unique feature of non-Hermitian systems is the skin effect, which is the extreme sensitivity to the boundary conditions. Here, we reveal that the skin effect originates from intrinsic non-Hermitian topology. Such a topological origin not merely explains the universal feature of the known skin effect, but also leads to new types of the skin effects-symmetry-protected skin effects. In particular, we discover the Z_{2} skin effect protected by time-reversal symmetry. On the basis of topological classification, we also discuss possible other skin effects in arbitrary dimensions. Our work provides a unified understanding about the bulk-boundary correspondence and the skin effects in non-Hermitian systems.

18.
Data Brief ; 27: 104702, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31720345

RESUMO

The data derives from a survey collected from 543 school-level teachers of English in Chile. The survey was originally distributed to 5435 teachers. The survey was developed with an aim of exploring teachers' beliefs about how second language grammar should be taught. The survey consisted of 50 items in total, in four sections: (a) background information (10 items), (b) beliefs regarding L2 learning and teaching (9 items), (c) beliefs regarding grammar instruction (23 items), and (d) classroom realities (8 items). Except for the background information section, the items took the form of a 6-point Likert scale. The entire dataset is included in an Excel file (.xlsx). The entire questionnaire is included as a supplementary file. The data is connected to the theoretical models proposed in [1]. In [1], those models were proposed based on descriptive statistics (e.g., agreement/disagreement rates) and focus-group interview data. Subsequently, in the current paper, the data was submitted to structural equation modelling to explain the theoretical models. Then, the data is visually depicted with figures created via AMOS.

19.
Phys Rev Lett ; 123(9): 097701, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31524453

RESUMO

Quantum phase transitions are intriguing and fundamental cooperative phenomena in physics. Analyzing a superconducting nanowire with spin-dependent non-Hermitian hopping, we discover a topological quantum phase transition driven by infinitesimal cascade instability. The anomalous phase transition is complementary to the universal non-Bloch wave behavior of non-Hermitian systems. We show that an infinite small magnetic field drastically suppresses the non-Hermitian skin effect, inducing a topological phase with Majorana boundary states. Furthermore, by identifying the bulk topological invariant, we establish the non-Hermitian bulk-boundary correspondence that does not have a Hermitian counterpart. We also discuss an experimental realization of the system by using the spin-current injection to a quantum wire.

20.
Phys Rev Lett ; 123(9): 097002, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31524460

RESUMO

In contrast to elementary Majorana particles, emergent Majorana fermions (MFs) in condensed-matter systems may have electromagnetic multipoles. We developed a general theory of magnetic multipoles for helical MFs on time-reversal-invariant superconductors. The results show that the multipole response is governed by crystal symmetry, and that a one-to-one correspondence exists between the symmetry of Cooper pairs and the representation of magnetic multipoles under crystal symmetry. The latter property provides a way to identify unconventional pairing symmetry via the magnetic response of helical MFs. We also find that most helical MFs exhibit a magnetic-dipole response, but those on superconductors with spin-3/2 electrons may display a magnetic-octupole response in leading order, which uniquely characterizes high-spin superconductors. Detection of such an octupole response provides direct evidence of high-spin superconductivity, such as in half-Heusler superconductors.

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