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We demonstrated a 978â nm laser diode (LD) side-pumped YSGG/Er:YSGG/YSGG composite crystal with a size of Ф 3 mm × 65 mm and continuous-wave (CW) mode. By optimizing resonator length and output mirror transmittance, a maximum output power of 28.02 W is generated, corresponding to slope efficiency of 17.55% and optical-optical efficiency of 12.29%, respectively. The thermal focal lengths are obtained by resonator stability condition. The laser wavelength is centered near 2.8â µm. Moreover, the beam quality factors M x2/M y2 are fitted to be 8.14 and 7.35, respectively. The above results indicate that a high-performance 2.8 µm CW laser can be achieved by LD side-pumped YSGG/Er:YSGG/YSGG composite crystal with excellent heat dissipation ability, which promotes effectively the development and applications of the mid-infrared solid-state lasers.
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A novel, easily synthesizable, shelf-stable electrophilic trifluoromethylselenolating reagent, N-trifluoromethylselenosaccharin, has been developed. This reagent can be synthesized in good yield by a two-step one-pot reaction from BnSeCF3, SO2Cl2, and silver saccharin. N-Trifluoromethylselenosaccharin proves to be an efficient trifluoromethylselenolating reagent, enabling the direct trifluoromethylselenolation of various electron-rich aromatic and heteroaromatic rings under mild reaction conditions. It exhibits excellent chemoselectivity and excellent compatibility with various functional groups, making it suitable for late-stage trifluoromethylselenolation applications in complex natural product and drug synthesis.
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The time response characteristic of the detector is crucial in radiation imaging systems. Unfortunately, existing parallel plate ionization chamber detectors have a slow response time, which leads to blurry radiation images. To enhance imaging quality, the electrode structure of the detector must be modified to reduce the response time. This paper proposes a gas detector with a grid structure that has a fast response time. In this study, the detector electrostatic field was calculated using COMSOL, while Garfield++ was utilized to simulate the detector's output signal. To validate the accuracy of simulation results, the experimental ionization chamber was tested on the experimental platform. The results revealed that the average electric field intensity in the induced region of the grid detector was increased by at least 33%. The detector response time was reduced to 27% -38% of that of the parallel plate detector, while the sensitivity of the detector was only reduced by 10%. Therefore, incorporating a grid structure within the parallel plate detector can significantly improve the time response characteristics of the gas detector, providing an insight for future detector enhancements.
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Radiometria , Tempo de Reação , Simulação por ComputadorRESUMO
We demonstrate the thermal, spectroscopy and laser properties of Ho,Pr doped YAP crystal grown successfully by Cz method. The thermal expansion coefficient, thermal conductivity, absorption and emission spectra of Ho,Pr:YAP crystal are investigated in detail. Additionally, the level lifetimes suggest that Pr3+ is a suitable deactivating ion for Ho:YAP crystal. Particularly, the actual laser performance is optimized by doping active ion Ho with high concentrations and introducing deactivated Pr3+, resulting in decreased laser threshold, increased laser output power and slope efficiency. A 3.01â µm laser with output power of 502â mW, slope efficiency of 6.3% and beam quality factors of 1.42/1.43 is achieved in the Ho,Pr:YAP crystal, as far as we know this is the highest â¼3â µm CW laser power realized in Ho3+ doped oxide crystals.
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In this work, we report on investigations of structure, spectroscopic properties and laser performances of, what we believe to be, a novel Er:YGGAG laser crystal. High crystalline quality is proved by an FWHW of XRC of 0.019°. Thermal conductivity of a 30 at.% Er:YGGAG crystal is determined as 4.98 W/(m·K). The refractive index is measured in the range of 400 to 1000â nm and fitting with Sellmeier equation is done. A broad fluorescence emission band is located at 2786â¼2819â nm, suggesting that this crystal is favorable to realize tunable and ultrafast laser. Under the pump at 969â nm with a fiber-coupled diode laser, at 400â Hz repetition rate and 600 µs pulse duration, the 30 at.% Er:YGGAG delivered maximum average power of 506â mW with overall optical-to-optical efficiency of 12.4% and slope efficiency of 16.9%. The laser beam quality was characterized by M2 factors of 1.53 and 1.39 in horizontal and vertical directions, respectively.
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Kerogen is mainly composed of carbon, hydrogen, and oxygen, which are the main components of crude oil and gas. The pyrolysis of kerogen is an efficient method to generate clean energy. In the present work, the pyrolysis reaction process of three types of kerogen is simulated using ReaxFF molecular dynamics (MD) methods to study the microscopic mechanism and the distribution of products. The results indicated that the pyrolysis products of the three types of kerogen significantly depend on the molecular structures, temperature, and reaction time. As the temperature increases, the gaseous hydrocarbon and the light and heavy oil fractions decreased, where small molecular fragments polymerized to form new molecular fragments. For an isothermal temperature, with the reaction proceeding, some component polymerization of the pyrolyzed fragments occurred, resulting in the generation of new light oils and heavy oils. Moreover, quantum chemical analysis was employed to reveal the kerogen pyrolysis mechanism. First, the weak bonds such as C-O, C-N, and C-S structures were decomposed to generate large carbon and some heavy shale oil fragments. Second, the cycloalkanes and long-chain alkanes were decomposed to generate a large amount of light shale oil and gaseous hydrocarbons. Finally, the decomposition of CâC in the aromatic ring, the secondary decomposition of light and heavy shale oils, and the further decomposition of short-chain alkanes occurred. In addition, the production of hydrogen (H2) occurred at the late stage of the pyrolysis reaction. Hydrogen radicals were formed by the decomposition of C-H bonds and subsequently collided with each other, resulting in the formation of H2 molecules. The pyrolysis and chemical analysis of kerogen can clearly determine the type and content of hydrocarbon substances, providing scientific data for exploration, development, and utilization of shale gas and shale oil.
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PURPOSE: This study aimed to quantitatively assess the incidence of hearing loss in relation to age in individuals with biallelic p.V37I variant in GJB2. METHODS: Population screening of the biallelic p.V37I variant was performed in 30,122 individuals aged between 0 and 97 years in Shanghai. Hearing thresholds of the biallelic p.V37I individuals and the controls were determined by click auditory brainstem response or pure tone audiometry. RESULTS: Biallelic p.V37I was detected in 0.528% (159/30,122) of the subjects. Of the biallelic p.V37I newborns, 43.91% (18/41) passed their distortion-product otoacoustic emissions-based newborn hearing screening or had hearing thresholds lower than 20 decible above normal hearing level. The older newborns had elevated hearing thresholds, with increasing incidence of 9.52%, 23.08%, 59.38%, and 80.00% for moderate or higher grade of hearing loss in age groups of 7 to 15 years, 20 to 40 years, 40 to 60 years, and 60 to 85 years, respectively. Their hearing deteriorated at a rate of 0.40 dB hearing level per year on average; males were more susceptible, and deterioration occurred preferentially at higher sound frequencies. CONCLUSION: The biallelic p.V37I variant is associated with steadily progressive hearing loss with increasing incidence over the course of life. Most of the biallelic p.V37I individuals may develop significant hearing loss in adulthood and, can benefit from early diagnosis and intervention through wide-spread genetic screening.
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Surdez , Perda Auditiva , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , China/epidemiologia , Conexina 26 , Conexinas/genética , Surdez/genética , Perda Auditiva/diagnóstico , Perda Auditiva/epidemiologia , Perda Auditiva/genética , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Promoting angiogenesis by targeting various angiogenic regulators has emerged as a new treatment strategy for myocardial ischemia (MI). MicroRNA-126 (miR-126) has been identified as the main regulator of compensatory angiogenesis; however, its role in MI is unclear. A rat MI model and an EA. hy926 endothelial cell hypoxia model were constructed and it was found that miR-126 was highly expressed in both models. The knockdown of HIF-1α expression in EA. hy926 cells in turn downregulated VEGF and CD34 expression and consequently inhibited angiogenesis. MiR-126 inhibitor inhibited EA. hy926 cell migration and tube formation as well as downregulated VEGF and CD34 expression, and these were reversed by transfection of miR-126 mimics. Rescue tests using miR-126 and HIF-1α demonstrated that miR-126-mediated regulation of angiogenesis was dependent on HIF-1α. In summary, miR-126 regulates the occurrence and progression of angiogenesis during MI via HIF-1α and may be a potential new therapeutic target.
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Antígenos CD34/química , Células Endoteliais/patologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , MicroRNAs/genética , Isquemia Miocárdica/patologia , Neovascularização Patológica/patologia , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Antígenos CD34/genética , Antígenos CD34/metabolismo , Hipóxia Celular , Células Endoteliais/metabolismo , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Masculino , MicroRNAs/antagonistas & inibidores , MicroRNAs/metabolismo , Isquemia Miocárdica/genética , Isquemia Miocárdica/metabolismo , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Ratos , Ratos Sprague-Dawley , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
This study investigated the effects of air temperature and ventilation on the sleep quality of elderly subjects and elucidated the mechanisms involved. Sixteen subjects aged over 65 years old were exposed to four conditions in a 2 × 2 design: air temperatures of 27°C and 30°C (with a ceiling fan in operation at 30°C) and two ventilation conditions (with and without mechanical ventilation) in experimental bedrooms. Their electroencephalogram, electrooculogram, chin electromyogram, electrocardiogram, respiration, oxygen saturation, and wrist skin temperature were measured continuously during sleep. Saliva samples were collected, and blood pressure was measured both before and after sleep. The results showed that at the temperature of 30°C, the total sleep time, sleep efficiency, and duration of REM sleep of the elderly decreased by 26.3 min, 5.5%, and 5.3 min, respectively, and time awake increased by 27.0 min, in comparison with 27°C, indicating that the sleep quality of the elderly is very vulnerable to heat exposure. Even a small heat load led to an overactive sympathetic nervous system and increased wrist skin temperature, which reduced sleep quality. Improving the ventilation increased the duration of deep sleep and REM sleep by 10.3 min and 3.7 min, respectively. Higher pollutant concentrations affected the respiration and autonomous nervous systems to reduce sleep quality. The benefits of improved thermal environment and ventilation on sleep quality were found to be additive. Good ventilation and the avoidance of raised temperatures in the bedroom are thus both important for the sleep quality of the elderly.
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Poluição do Ar em Ambientes Fechados , Qualidade do Sono , Idoso , Humanos , Temperatura , Respiração , Sono/fisiologiaRESUMO
The feasibility of a scheme in which the concentration of CO2 in gas-liquid solution is directly measured based on PZT piezoelectric-photoacoustic spectroscopy was evaluated. The existing device used for the measurement of gas concentration in gas-liquid solution has several limitations, including prolonged duration, loss of gas, and high cost due to the degassing component. In this study, we developed a measuring device in order to solve the problems mentioned above. Using this device, how the intensity of the photoacoustic signal changes with the concentration of CO2 was demonstrated through experiment. The impact that variation of the laser modulation frequency has on the photoacoustic signal was also studied. Furthermore, the experimental data generated from measuring the concentration of CO2 in gas-liquid solution was verified for a wide range of concentrations. It was found that, not only can the error rate of the device be less than 7%, but the time of measurement can be within 60 s. To sum up, the scheme is highly feasible according to the experimental results, which makes measurement of the concentration of a gas in gas-liquid solution in the future more straightforward.
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BACKGROUND: DNA methylation and miRNA-target genes play an important part in the early development of various tumors and have been studied as tumor biomarkers. Although previous studies have reported a cluster of molecular events (such as aberrant alterations of genomics and epigenetics), little is known of the potential biomarkers for early diagnosis and prognostic evaluation in head and neck squamous cell carcinoma (HNSCC). METHODS: Multiple bioinformatics tools based on The Cancer Genome Atlas (TCGA) database and clinical samples were applied to evaluate the beneficial biomarkers in HNSCC. We focused on the role of plasminogen activator urokinase (PLAU), including diagnostic and prognostic significance, gene expression analysis, aberrant DNA methylation characteristics, interaction of miRNAs and associated signaling pathways. RESULTS: We found that PLAU was aberrantly upregulated in HNSCC, regardless of the mRNA or protein level. The results of receiver operating characteristic (ROC) curve and Cox regression analysis revealed that PLAU was a diagnostic and independent prognostic factor for patients with HNSCC. Hypomethylation of PLAU was closely related to poor survival in HNSCC. Additionally, miR-23b-3p was predicted to target PLAU and was significantly downregulated in HNSCC tissues. Therefore, our findings suggested that PLAU functioned as a promoter in the pathological process of HNSCC. DNA hypomethylation and downregulation of miR-23b-3p were associated with PLAU overexpression. Finally, our findings provided evidence of a significant interaction between PLAU-target and miRNAs-target pathways, indicating that miR-23b-3p suppresses malignant properties of HNSCC by targeting PLAU via Ras/MAPK and Akt/mTOR signaling pathways. CONCLUSIONS: PLAU is overexpressed and may serve as an independent diagnostic and prognostic biomarker in HNSCC. Hypomethylation and downregulation of miR-23b-3p might account for the oncogenic role of PLAU in HNSCC.
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BACKGROUND: Glutathione is a potential therapy for systemic lupus erythematosus, but its role in allergic rhinitis (AR) has not been determined. This report probed into the actions of glutathione in AR, so as to supplement evidence for a therapeutical countermeasure for AR. METHODS: In this study, peripheral blood mononuclear cells (PBMCs) of patients were extracted and processed with glutathione. PBMCs and nasal mucosa tissues were collected from AR mouse models treated with or without glutathione. The proportions of Th17/Treg cell markers and autophagy-related molecules in the nasal mucosa, PBMCs or Th17/Treg cells were assessed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB) or flow cytometry analysis, and serum contents of related factors were analyzed by enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin (HE) staining was applied to observe the thickness of mouse mucosa. RESULTS: IL-17A, RORγt, Beclin1 and LC3-II/LC3-I levels were increased in AR patients, while Foxp3 and P62 were decreased. The serum contents of IL-17A and eosinophil cationic protein (ECP) in AR patients were elevated, but IL-10 level was reduced. In PBMCs of AR patients, the levels of IL-17A and LC3-II were increased, and the levels of Foxp3 and P62 were decreased, while these changes could be reversed by glutathione. In AR mouse models, glutathione could balance Th17/Treg cells, reduce autophagy, correct the levels of related cytokines in mouse serum, and shrunk mucosa thickness. CONCLUSION: Glutathione could rescue the imbalance of Treg/Th17 cells by suppressing intracellular autophagy, which might be beneficial to the treatment of AR patients.
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Autofagia/imunologia , Glutationa/farmacologia , Líquido Intracelular/imunologia , Rinite Alérgica/imunologia , Linfócitos T Reguladores/imunologia , Células Th17/imunologia , Adulto , Animais , Autofagia/efeitos dos fármacos , Células Cultivadas , Feminino , Glutationa/uso terapêutico , Humanos , Líquido Intracelular/efeitos dos fármacos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Mucosa Nasal/efeitos dos fármacos , Mucosa Nasal/imunologia , Mucosa Nasal/patologia , Rinite Alérgica/tratamento farmacológico , Rinite Alérgica/patologia , Linfócitos T Reguladores/efeitos dos fármacos , Células Th17/efeitos dos fármacosRESUMO
We consider a C_{6} invariant lattice of magnetic moments coupled via a Kondo exchange J with a 2D electron gas (2DEG). The effective Ruderman-Kittel-Kasuya-Yosida interaction between the moments stabilizes a magnetic skyrmion crystal in the presence of magnetic field and easy-axis anisotropy. An attractive aspect of this mechanism is that the magnitude of the magnetic ordering wave vectors, Q_{ν} (ν=1, 2, 3), is dictated by the Fermi wave number k_{F}: |Q_{ν}|=2k_{F}. Consequently, the topological contribution to the Hall conductivity of the 2DEG becomes of the order of the quantized value, e^{2}/h, when J is comparable to the Fermi energy ε_{F}.
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We introduce an extension of the Kitaev honeycomb model by including four-spin interactions that preserve the local gauge structure and, hence, the integrability of the original model. The extended model has a rich phase diagram containing five distinct vison crystals, as well as a symmetric π-flux spin liquid with a Fermi surface of Majorana fermions and a sequence of Lifshitz transitions. We discuss possible experimental signatures and, in particular, present finite-temperature Monte Carlo calculations of the specific heat and the static vison structure factor. We argue that our extended model emerges naturally from generic perturbations to the Kitaev honeycomb model.
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The effect of elevated airflow on sleep quality was investigated with 18 elderly. Three airflow conditions were set: ceiling fan/30°C/max.0.8 m/s and mean 0.7 m/s, task fan/30°C/max.0.8 m/s and mean 0.6 m/s, and thermally neutral /27°C/0.2 m/s. Sleep quality was evaluated objectively by analysis of electroencephalogram signals that were continuously monitored during the sleeping period. Urinary cortisol concentrations were analyzed to measure the activity of sympathetic nervous system. No significant difference in sleep quality, thermal comfort, or cortisol concentration was found between the ceiling fan and the neutral condition. The duration of total sleep time decreased by 35 minutes, the duration of REM sleep decreased by 15 minutes, and the cortisol concentration in the morning increased by 50 ng/mL in the task fan than the other two conditions. Compared with ceiling fan, less heat load was removed in the task fan condition, possibly due to the lower air speed. This study shows that even small heat load led to reduced sleep quality and overactive sympathetic nervous system of the elderly. By supplying an airflow of 0.8 m/s evenly over the human body, the elderly could maintain sleep quality and thermal comfort at an air temperature that was 3 K higher than the neutral temperature.
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Ar Condicionado/métodos , Temperatura Alta/efeitos adversos , Distúrbios do Início e da Manutenção do Sono/prevenção & controle , Sono/fisiologia , Idoso , Temperatura Corporal , Feminino , Humanos , Hidrocortisona/urina , Masculino , Polissonografia , Fenômenos Fisiológicos Respiratórios , Distúrbios do Início e da Manutenção do Sono/etiologia , Distúrbios do Início e da Manutenção do Sono/urina , Fatores de TempoRESUMO
BACKGROUND: Atherosclerosis (AS) is one of the main causes of cardiovascular disease. AS plaques often occur in blood vessels with oscillatory blood flow and their formation can be regulated by microRNAs (miRNAs). The aim of this study is to identify the key miRNAs and molecular pathways involved in this pathological process. METHODS: In this study, gene chip data obtained from the GEO database was analyzed using the LIMMA package to find differentially expressed miRNAs (DE miRNAs) in the carotid arteries of ApoE-/- mice exposed to different blood flow rates. Predicted targets of the DE miRNAs were identified using the TargetScan, miRDB, and DIANA databases respectively, and the potential target genes (PTGs) were found by analyzing the common results of three databases. The DAVID database was used to enrich the PTGs based on gene ontology (GO) and pathway (Kyoto Encyclopedia of Genes and Genomes, KEGG), and the STRING database was used to uncover any protein-protein interactions (PPI) of the PTGs. RESULTS: The networks of the DE miRNAs-PTGs, Pathway-PTGs-DE miRNAs, and PTGs PPI, were constructed using Cytoscape, and 11 up-regulated and 13 down-regulated DE miRNAs and 1479 PTGs were found. GO results showed that PTGs were significantly enriched in functions such as transcriptional regulation and DNA binding. KEGG results showed that PTGs were significantly enriched in inflammation-related mitogen-activated protein kinase (MAPK) and AS-related FOXO pathways. The PPI network revealed some key target genes in the PTGs. CONCLUSIONS: The analysis of key miRNAs and molecular pathways that regulate the formation of AS plaques induced by oscillatory blood flow will provide new ideas for AS treatment.
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Velocidade do Fluxo Sanguíneo , Artérias Carótidas/metabolismo , Artérias Carótidas/fisiopatologia , MicroRNAs/genética , Animais , Aterosclerose/etiologia , Aterosclerose/metabolismo , Aterosclerose/fisiopatologia , Biologia Computacional/métodos , Suscetibilidade a Doenças , Perfilação da Expressão Gênica , Ontologia Genética , Redes Reguladoras de Genes , Camundongos , Camundongos Knockout para ApoE , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Fluxo Sanguíneo Regional , Resistência ao Cisalhamento , Transdução de Sinais , TranscriptomaRESUMO
BACKGROUND: YiqiHuoxue decoction (YHD) is frequently prescribed to prevent and treat cardiovascular diseases. YHD inhibits platelet aggregation, however the underlying mechanisms are unclear. METHODS: The in vitro and in vivo anti-platelet and antithrombotic effects of YHD and ethanol-precipitated YHD (EYHD) and underlying mechanisms were investigated. Forty-six Sprague-Dawley (SD) rats and 36 male Kunming mice were examined. Ten SD rats were used to assess the cytotoxicity of YHD and EYHD by releasing lactate dehydrogenase from treated platelets. The remaining 36 SD rats were divided into six groups (six per group), including control saline (5 mL/kg), aspirin (20 mg/kg), YHD low dosage (0.2 g/kg), YHD high dosage (2.0 g/kg), 75% EYHD low dosage (0.2 g/kg), and 75% EYHD high dosage (2.0 g/kg) groups to detect platelet aggregation; the 36 Kunming mice were divided into 6 groups to detect mesenteric arterial thrombosis induction. Thromboxane B2 (TXB2) levels were determined by enzyme immunoassay. RESULTS: YHD high dosage and 75% EYHD (low and high dosage) inhibited ADP-induced platelet aggregation. Moreover, collagen-induced platelet aggregation was significantly suppressed by YHD (high dosage), 75% EYHD (high dosage), and 75% EYHD (low dose). Rats given 75% EYHD (high dose) displayed a marked reduction in collagen-induced platelet aggregation at 2 h post-administration. YHD and EYHD markedly prolonged the onset of thrombosis causing loose attachment of the thrombus to the vascular endothelium, but bleeding and clotting times were not significantly changed. Finally, YHD and EYHD markedly reduced TXB2 levels. CONCLUSIONS: YHD and EYHD effectively inhibit platelet activation and thrombosis, presumably by suppressing TXB2.
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We study the excitation spectrum in the dimer phase of the Shastry-Sutherland model by using an unbiased variational method that works in the thermodynamic limit. The method outputs dynamical correlation functions in all possible channels. This output is exploited to identify the order parameters with the highest susceptibility (single or multitriplon condensation in a specific channel) upon approaching a quantum phase transition in the magnetic field versus the J^{'}/J phase diagram. We find four different instabilities: antiferro spin nematic, plaquette spin nematic, stripe magnetic order, and plaquette order, two of which have been reported in previous studies.
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We discuss noncollinear magnetic phenomena whose local order parameter is characterized by more than one spin vector. By focusing on the simple cases of 2D triangular and 3D pyrochlore lattices, we demonstrate that their low-energy theories can be described by a one-parametric class of sigma models continuously interpolating between the classical Heisenberg model and the principal chiral model Tr(∂_{a}U∂_{a}U^{}) for all U∈SU(2). The target space can be viewed as a U(1) fibration over the CP(1) space. The 3D version of our model is further generalized to break spatial and spin rotation symmetry SO(3)×SO(3)âSO(3).
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This corrects the article DOI: 10.1103/PhysRevLett.116.247203.