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1.
ACS Appl Mater Interfaces ; 16(40): 53541-53554, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39344595

RESUMO

Hydrogels have garnered tremendous attention for their applications in the repair of intervertebral disk (IVD) degeneration and postoperative IVD defects. However, it is still challenging to develop a hydrogel fulfilling the requirements for high mechanical properties, adhesive capability, biocompatibility, antibacterial properties, and anti-inflammatory performance. Herein, we report a multifunctional double-network (DN) hydrogel composed of physically cross-linked carboxymethyl chitosan (CMCS) and tannic acid (TA) networks as well as chemically cross-linked acrylamide (AM) networks, which integrates the properties of high strength, adhesion, biocompatibility, antimicrobial activity, and anti-inflammation for the repair of postoperative IVD defects. The treatment with CMCS/TA/PAM DN hydrogels can significantly decrease the levels of inflammatory cytokines and degeneration-related factors and upregulated collagen type II alpha 1. In addition, the hydrogels can effectively seal the annulus fibrosus defect, prevent nucleus pulposus degeneration, retain IVD height, and restore the biomechanical properties of the disc to some extent. This polyphenol-mediated DN hydrogel is promising for sealing IVD defects and preventing herniation after lumbar discectomy.


Assuntos
Anti-Inflamatórios , Quitosana , Hidrogéis , Degeneração do Disco Intervertebral , Hidrogéis/química , Hidrogéis/farmacologia , Animais , Quitosana/química , Quitosana/análogos & derivados , Quitosana/farmacologia , Degeneração do Disco Intervertebral/cirurgia , Degeneração do Disco Intervertebral/tratamento farmacológico , Degeneração do Disco Intervertebral/patologia , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Taninos/química , Taninos/farmacologia , Taninos/uso terapêutico , Polifenóis/química , Polifenóis/farmacologia , Disco Intervertebral/cirurgia , Disco Intervertebral/efeitos dos fármacos , Disco Intervertebral/patologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Masculino
2.
BMC Cardiovasc Disord ; 24(1): 510, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39327565

RESUMO

OBJECTIVE: This study investigated the relationship of serum homocysteine (Hcy) and cystatin C (Cys C) levels with the prognosis of patients with heart failure with preserved ejection fraction (HFpEF). METHODS: A total of 178 patients with HFpEF who were admitted to our hospital between December 2019 and November 2020 were included. Patients were grouped based on their serum Hcy and Cys C levels: high Hcy level, normal Hcy level, high Cys C level, and normal Cys C level. Cardiac function, ventricular remodeling indices, and prognosis were compared among patients in these groups. Additionally, the predictive value of serum Hcy and Cys C levels for adverse cardiovascular events in HFpEF patients was analyzed. RESULTS: Patients' mean age in the high Hcy level, normal Hcy level, high Cys C level, and normal Cys C level groups was 69.21 ± 4.17,67.74 ± 4.28,69.95 ± 4.98, and 67.06 ± 4.13 years old, respectively. The high Hcy level group exhibited a lower proportion of class II cardiac function according to the New York Heart Association (NYHA) classification and a higher proportion of class IV cardiac function than the normal Hcy level group, with statistically significant differences. Similarly, the high Cys C level group had a lower proportion of class II cardiac function and a higher proportion of class IV cardiac function compared with the normal Cys C level group, with statistically significant differences. Left ventricular end-diastolic internal diameter (LVEDD), left ventricular end-systolic internal diameter (LVESD), and left ventricular mass index (LVMI) were significantly higher in both the high Hcy level and high Cys C level groups compared with the normal group, with statistically significant differences. The rates of all-cause mortality and class I endpoint events were significantly higher in the high Hcy level and high Cys C level groups than in the normal group. Multifactorial logistic regression analysis demonstrated that adverse cardiovascular events were significantly associated with cardiac function class, LVEDD, LVESD, LVMI, Hcy, and Cys C in patients with HFpEF. The area under the curve (AUC) values for Hcy and Cys C, determined using receiver operating characteristic (ROC) curve analysis, were 0.778 (optimal critical value, 25.38) and 0.681 (optimal critical value, 1.56), respectively, for predicting adverse cardiovascular events. Both Hcy and Cys C serum levels were positively correlated with LVEDD, LVESD, LVMI, and NYHA classification. CONCLUSION: Serum levels of Hcy and Cys C were closely associated with cardiac function, ventricular remodeling indices, and prognosis in patients with HFpEF. These levels may serve as valuable indices for assessing HFpEF patients' health status and prognosis, providing important insights into their potential role as biomarkers for HFpEF management and prognosis.


Assuntos
Biomarcadores , Cistatina C , Insuficiência Cardíaca , Homocisteína , Valor Preditivo dos Testes , Volume Sistólico , Função Ventricular Esquerda , Humanos , Homocisteína/sangue , Cistatina C/sangue , Masculino , Feminino , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/mortalidade , Biomarcadores/sangue , Idoso , Prognóstico , Pessoa de Meia-Idade , Medição de Risco , Estudos Retrospectivos , Remodelação Ventricular , Fatores de Risco
3.
Nat Mater ; 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39134650

RESUMO

Hexagonal boron nitride (hBN) has emerged as a promising protection layer for dielectric integration in the next-generation large-scale integrated electronics. Although numerous efforts have been devoted to growing single-crystal hBN film, wafer-scale ultraflat hBN has still not been achieved. Here, we report the epitaxial growth of 4 in. ultraflat single-crystal hBN on Cu0.8Ni0.2(111)/sapphire wafers. The strong coupling between hBN and Cu0.8Ni0.2(111) suppresses the formation of wrinkles and ensures the seamless stitching of parallelly aligned hBN domains, resulting in an ultraflat single-crystal hBN film on a wafer scale. Using the ultraflat hBN as a protective layer, we integrate the wafer-scale ultrathin high-κ dielectrics onto two-dimensional (2D) materials with a damage-free interface. The obtained hBN/HfO2 composite dielectric exhibits an ultralow current leakage (2.36 × 10-6 A cm-2) and an ultrathin equivalent oxide thickness of 0.52 nm, which meets the targets of the International Roadmap for Devices and Systems. Our findings pave the way to the synthesis of ultraflat 2D materials and integration of future 2D electronics.

4.
Sci Rep ; 14(1): 20087, 2024 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-39209941

RESUMO

To compare the clinical efficacy of interlaminar endoscopic surgical system delta (iLESSYS-Delta) discectomy with that of classical fenestration discectomy for treating lumbar disc herniation. Patients who underwent iLESSYS-Delta or fenestration discectomy were enrolled in this study. Baseline information and clinical indicators were collected. The baseline data were matched using propensity score matching. Fifty-two patients were in each group. In the iLESSYS-Delta cohort, the volume of intraoperative bleeding was 18.17 ± 4.20 ml, the length of postoperative hospital stay was 4.16 ± 2.29 days, and the length of postoperative off-bed activity was 1.58 ± 0.88 days. In contrast, in the fenestration group, the volume of intraoperative bleeding was 32.50 ± 17.13 ml, the length of postoperative hospital stay was 6.66 ± 2.44 days, and the length of postoperative off-bed activity was 3.18 ± 1.28 days. The difference between the two groups was statistically significant (P < 0.05). The operation time was 88.90 ± 19.14 min in the iLESSYS-Delta group and 67.63 ± 19.32 min in the fenestration group, and the difference between the two groups was statistically significant (P < 0.05). Regarding the pain visual analogue scale scores at 24, 48, and 72 h after surgery, patients in the iLESSYS-Delta group had less pain than did those in the fenestration group (P < 0.05). The Oswestry disability indices of postoperative patients in both groups significantly improved at 3 months after surgery and at the last follow-up (P < 0.05); however, there was no statistically significant difference in the postoperative ODI scores between the two surgery groups (P > 0.05). The two groups showed no significant differences in clinical effects, postoperative recurrence rates, or perioperative complications. iLESSYS-Delta can cause less intraoperative bleeding and faster recovery than fenestration discectomy.


Assuntos
Discotomia , Endoscopia , Deslocamento do Disco Intervertebral , Vértebras Lombares , Humanos , Masculino , Feminino , Deslocamento do Disco Intervertebral/cirurgia , Estudos Retrospectivos , Pessoa de Meia-Idade , Endoscopia/métodos , Adulto , Discotomia/métodos , Discotomia/efeitos adversos , Resultado do Tratamento , Vértebras Lombares/cirurgia , Tempo de Internação , Duração da Cirurgia
5.
Orthop Surg ; 16(8): 2052-2065, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38952050

RESUMO

BACKGROUND: The reaserch of artificial intelligence (AI) model for predicting spinal refracture is limited to bone mineral density, X-ray and some conventional laboratory indicators, which has its own limitations. Besides, it lacks specific indicators related to osteoporosis and imaging factors that can better reflect bone quality, such as computed tomography (CT). OBJECTIVE: To construct a novel predicting model based on bone turn-over markers and CT to identify patients who were more inclined to suffer spine refracture. METHODS: CT images and clinical information of 383 patients (training set = 240 cases of osteoporotic vertebral compression fractures (OVCF), validation set = 63, test set = 80) were retrospectively collected from January 2015 to October 2022 at three medical centers. The U-net model was adopted to automatically segment ROI. Three-dimensional (3D) cropping of all spine regions was used to achieve the final ROI regions including 3D_Full and 3D_RoiOnly. We used the Densenet 121-3D model to model the cropped region and simultaneously build a T-NIPT prediction model. Diagnostics of deep learning models were assessed by constructing ROC curves. We generated calibration curves to assess the calibration performance. Additionally, decision curve analysis (DCA) was used to assess the clinical utility of the predictive models. RESULTS: The performance of the test model is comparable to its performance on the training set (dice coefficients of 0.798, an mIOU of 0.755, an SA of 0.767, and an OS of 0.017). Univariable and multivariable analysis indicate that T_P1NT was an independent risk factor for refracture. The performance of predicting refractures in different ROI regions showed that 3D_Full model exhibits the highest calibration performance, with a Hosmer-Lemeshow goodness-of-fit (HL) test statistic exceeding 0.05. The analysis of the training and test sets showed that the 3D_Full model, which integrates clinical and deep learning results, demonstrated superior performance with significant improvement (p-value < 0.05) compared to using clinical features independently or using only 3D_RoiOnly. CONCLUSION: T_P1NT was an independent risk factor of refracture. Our 3D-FULL model showed better performance in predicting high-risk population of spine refracture than other models and junior doctors do. This model can be applicable to real-world translation due to its automatic segmentation and detection.


Assuntos
Aprendizado Profundo , Fraturas por Compressão , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Tomografia Computadorizada por Raios X , Humanos , Feminino , Fraturas da Coluna Vertebral/diagnóstico por imagem , Masculino , Idoso , Estudos Retrospectivos , Pessoa de Meia-Idade , Fraturas por Osteoporose/diagnóstico por imagem , Fraturas por Compressão/diagnóstico por imagem , Recidiva , Idoso de 80 Anos ou mais , Imageamento Tridimensional
6.
Nano Lett ; 24(28): 8587-8594, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38967395

RESUMO

Single-unit cell (1 UC) FeSe interfaced with TiOx or FeOx exhibits significantly enhanced superconductivity compared to that of bulk FeSe, with interfacial electron-phonon coupling (EPC) playing a crucial role. However, the reduced dimensionality in 1 UC FeSe, which may drive superconducting fluctuations, complicates our understanding of the enhancement mechanisms. We construct a new superconducting interface, 1 UC FeSe/SrVO3/SrTiO3. Here, the itinerant electrons of highly metallic SrVO3 films can screen all high-energy Fuchs-Kliewer phonons, including those of SrTiO3, making it the first FeSe/oxide system with screened interfacial EPC while maintaining the 1 UC FeSe thickness. Despite comparable doping levels, the heavily electron-doped 1 UC FeSe/SrVO3 exhibits a pairing temperature (Tg ∼ 48 K) lower than those of FeSe/SrTiO3 and FeSe/LaFeO3. Our findings disentangle the contributions of interfacial EPC from dimensionality in terms of enhancing Tg in FeSe/oxide interfaces, underscoring the critical importance of interfacial EPC. This FeSe/VOx interface also provides a platform for studying interfacial superconductivity.

7.
Artigo em Inglês | MEDLINE | ID: mdl-38870507

RESUMO

Objective: This study examines the relationship between serum biomarkers sLOX-1, S100A12, D-dimer and the risk of cerebral hemorrhage transformation following intravenous thrombolysis in stroke patients. Methods: We retrospectively analyzed 161 stroke patients who underwent intravenous thrombolysis at our hospital from March 2021 to March 2023. Patients were categorized into hemorrhagic transformation (n=35) and non-hemorrhagic transformation groups (n=126) based on head CT scans conducted within 3 days post-treatment. We compared serum levels of sLOX-1, S100A12, and D-dimer between the groups and analyzed clinical data to evaluate factors influencing hemorrhagic transformation. Results: No significant differences were found in demographics, medical history, or stroke characteristics between the groups (P > .05). The hemorrhagic transformation group exhibited higher NIHSS scores, WBC levels, and lower UA levels (P < .05). Notably, sLOX-1, S100A12, and D-dimer levels were significantly elevated in the hemorrhagic group (P < .05). Multivariate regression and ROC curve analyses indicated these biomarkers and NIHSS scores significantly predict cerebral hemorrhage post-thrombolysis (P < .05). Conclusion: Elevated sLOX-1, S100A12, and D-dimer levels are associated with an increased risk of cerebral hemorrhage transformation after thrombolysis in stroke patients. These biomarkers along with NIHSS and NIHSS scores, hold diagnostic value for predicting hemorrhagic outcomes.

8.
Nat Commun ; 15(1): 3418, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38653990

RESUMO

In single unit-cell FeSe grown on SrTiO3, the superconductivity transition temperature features a significant enhancement. Local phonon modes at the interface associated with electron-phonon coupling may play an important role in the interface-induced enhancement. However, such phonon modes have eluded direct experimental observations. The complicated atomic structure of the interface brings challenges to obtain the accurate structure-phonon relation knowledge. Here, we achieve direct characterizations of atomic structure and phonon modes at the FeSe/SrTiO3 interface with atomically resolved imaging and electron energy loss spectroscopy in an electron microscope. We find several phonon modes highly localized (~1.3 nm) at the unique double layer Ti-O terminated interface, one of which (~ 83 meV) engages in strong interactions with the electrons in FeSe based on ab initio calculations. This finding of the localized interfacial phonon associated with strong electron-phonon coupling provides new insights into understanding the origin of superconductivity enhancement at the FeSe/SrTiO3 interface.

9.
Nat Commun ; 15(1): 1938, 2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38431679

RESUMO

Phonon splitting of the longitudinal and transverse optical modes (LO-TO splitting), a ubiquitous phenomenon in three-dimensional polar materials, will break down in two-dimensional (2D) polar systems. Theoretical predictions propose that the LO phonon in 2D polar monolayers becomes degenerate with the TO phonon, displaying a distinctive "V-shaped" nonanalytic behavior near the center of the Brillouin zone. However, the full experimental verification of these nonanalytic behaviors has been lacking. Here, using monolayer hexagonal boron nitride (h-BN) as a prototypical example, we report the comprehensive and direct experimental verification of the nonanalytic behavior of LO phonons by inelastic electron scattering spectroscopy. Interestingly, the slope of the LO phonon in our measurements is lower than the theoretically predicted value for a freestanding monolayer due to the screening of the Cu foil substrate. This enables the phonon polaritons in monolayer h-BN/Cu foil to exhibit ultra-slow group velocity (~5 × 10-6 c, c is the speed of light) and ultra-high confinement (~ 4000 times smaller wavelength than that of light). These exotic behaviors of the optical phonons in h-BN presents promising prospects for future optoelectronic applications.

10.
Cell Mol Life Sci ; 81(1): 49, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38252317

RESUMO

Intervertebral disc degeneration (IVDD) is one of the most prevalent spinal degenerative disorders and imposes places heavy medical and economic burdens on individuals and society. Mechanical overloading applied to the intervertebral disc (IVD) has been widely recognized as an important cause of IVDD. Mechanical overloading-induced chondrocyte ferroptosis was reported, but the potential association between ferroptosis and mechanical overloading remains to be illustrated in nucleus pulposus (NP) cells. In this study, we discovered that excessive mechanical loading induced ferroptosis and endoplasmic reticulum (ER) stress, which were detected by mitochondria and associated markers, by increasing the intracellular free Ca2+ level through the Piezo1 ion channel localized on the plasma membrane and ER membrane in NP cells. Besides, we proposed that intracellular free Ca2+ level elevation and the activation of ER stress are positive feedback processes that promote each other, consistent with the results that the level of ER stress in coccygeal discs of aged Piezo1-CKO mice were significantly lower than that of aged WT mice. Then, we confirmed that selenium supplementation decreased intracellular free Ca2+ level by mitigating ER stress through upregulating Selenoprotein K (SelK) expression. Besides, ferroptosis caused by the impaired production and function of Glutathione peroxidase 4 (GPX4) due to mechanical overloading-induced calcium overload could be improved by selenium supplementation through Se-GPX4 axis and Se-SelK axis in vivo and in vitro, eventually presenting the stabilization of the extracellular matrix (ECM). Our findings reveal the important role of ferroptosis in mechanical overloading-induced IVDD, and selenium supplementation promotes significance to attenuate ferroptosis and thus alleviates IVDD, which might provide insights into potential therapeutic interventions for IVDD.


Assuntos
Ferroptose , Degeneração do Disco Intervertebral , Núcleo Pulposo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Selênio , Selenoproteínas , Animais , Humanos , Camundongos , Membrana Celular , Canais Iônicos , Selenoproteínas/metabolismo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo
11.
Artigo em Inglês | MEDLINE | ID: mdl-37957941

RESUMO

BACKGROUND: The cephalic vein is often used in for arteriovenous fistula creation; however, the cephalic vein variation is common. This study will propose new theoretical explanations for a new discovered variation of cephalic vein draining into external jugular vein with "T-junction" shape by means of 3D computational hemodynamic modeling, which may provide reference for clinical practice. METHODS: The precise measurements were conducted for the variant right cephalic vein draining into external jugular vein and for a normal right cephalic vein as a control. After processing the anatomical data, 3D geometrical model was reconstructed. Then, the influent field inside the variant jugulocephalic vein was mathematically modeled to get a detailed description of hemodynamic environment. RESULTS: The anatomical parameters of the "T-junction" jugulocephalic vein variant were much more different from the normal right cephalic vein. The wall shear stress of variant cephalic vein at the corresponding position was higher and changed more rapidly than that of normal cephalic vein. The shear rate contour lines are disordered in several areas of the variant cephalic vein, indicating that the hemodynamic parameters in these areas are unstable. The hemodynamic characteristics at the confluence of the variant cephalic vein are more complex, with more areas where hemodynamic parameters are disrupted. CONCLUSIONS: The variation of cephalic arch in a "T-junction" with external jugular vein largely altered the fluid dynamics, especially in hemodialysis patients with brachiocephalic fistula in terms of the simulating flow in 3D computational model. This computational model provides hemodynamic profiles for stabilizing or modulating fluid dynamics in patients with jugulocephalic vein variant after brachiocephalic fistula.

12.
Phys Rev Lett ; 131(11): 116602, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37774282

RESUMO

Phonons, as the most fundamental emergent bosons in condensed matter systems, play an essential role in the thermal, mechanical, and electronic properties of crystalline materials. Recently, the concept of topology has been introduced to phonon systems, and the nontrivial topological states also exist in phonons due to the constraint by the crystal symmetry of the space group. Although the classification of various topological phonons has been enriched theoretically, experimental studies were limited to several three-dimensional (3D) single crystals with inelastic x-ray or neutron scatterings. The experimental evidence of topological phonons in two-dimensional (2D) materials is absent. Here, using high-resolution electron energy loss spectroscopy following our theoretical predictions, we directly map out the phonon spectra of the atomically thin graphene in the entire 2D Brillouin zone, and observe two nodal-ring phonons and four Dirac phonons. The closed loops of nodal-ring phonons and the conical structure of Dirac phonons in 2D momentum space are clearly revealed by our measurements, in nice agreement with our theoretical calculations. The ability of 3D mapping (2D momentum space and energy space) of phonon spectra opens up a new avenue to the systematic identification of the topological phononic states. Our work lays a solid foundation for potential applications of topological phonons in superconductivity, dynamic instability, and phonon diode.

13.
Adv Sci (Weinh) ; 10(7): e2205707, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36646514

RESUMO

Birefringence, which modulates the polarization of electromagnetic wave, has been commercially developed and widely used in modern photonics. Fostered by high-frequency signal processing and communications, feasible birefringence technologies operating in gigahertz (GHz) range are highly desired. Here, a coherent phonon-induced GHz optical birefringence and its manipulation in SrTiO3 (STO) crystals are demonsrated. With ultrafast laser pumping, the coherent acoustic phonons with low damping are created in the transducer/STO structures. A series of transducer layers are examined and the optimized one with relatively high photon-phonon conversion efficiency, i.e., semiconducting LaRhO3 film, is obtained. The most intriguing finding here is that, by virtue of high sensitivity to strain perturbation of STO, GHz optical birefringence can be induced by the coherent acoustic phonons and the birefringent amplitudes possess crystal orientation dependence. Optical manipulation of both coherent phonons and its induced GHz birefringence by double pump technique are also realized. These findings reveal an alternative mechanism of ultrafast optical birefringence control, and offer prospects for applications in high-frequency acoustic-optics devices.

14.
Lipids Health Dis ; 21(1): 129, 2022 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-36463190

RESUMO

BACKGROUND: Little is known about the link between the monocyte to high-density lipoprotein cholesterol ratio (MHR) and frequent premature ventricular complexes (PVCs). This investigation aimed to evaluate the link between the MHR and frequent PVCs in patients, as well as their outcomes, using the axis, burden, coupling interval-ventricular tachycardia (ABC-VT) risk score (ARS). METHODS: Two hundred patients with frequent PVCs and 70 controls were retrospectively enrolled, and their general data were gathered. The MHR and ARS were calculated. Then, patients developing frequent PVCs were classified into a medium-/high-risk subgroup and a low-risk subgroup according to ARS. The results were evaluated employing comparative statistical analyses, Spearman's correlation, logistic regression analyses, and receiver operating characteristic (ROC) curves. RESULTS: The MHR in the controls was obviously lower than that in the frequent PVC group. In addition, the MHR was the lowest in the control group and highest in the medium-/high-risk subgroup, with that of the low-risk subgroup falling in the middle. Spearman's correlation analyses showed that the MHR was positively correlated with the ARS (ρ = 0.307, P < 0.001). Ultimately, the MHR was found to be a risk factor for frequent PVCs in the multivariate analysis. In addition, an MHR cutoff point of 254.6 featured 67.50% sensitivity and 67.14% specificity for predicting frequent PVCs, and the area under the curve (AUC) reached 0.694 (95% confidence interval: 0.623-0.766) (P < 0.001). CONCLUSIONS: The MHR is positively and independently correlated with frequent PVCs and can be used as a practical, cost-saving and simple biomarker of inflammation owing to its value in predicting frequent PVCs. In addition, the MHR is crucial to risk stratification and prognosis, which may give it clinical value in the prevention and management of frequent PVCs.


Assuntos
Monócitos , Humanos , HDL-Colesterol , Estudos Retrospectivos , Fatores de Risco , Área Sob a Curva
15.
Phys Rev Lett ; 129(18): 187601, 2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36374677

RESUMO

1T-TiSe_{2} is one of the most studied charge density wave (CDW) systems, not only because of its peculiar properties related to the CDW transition, but also due to its status as a promising candidate of exciton insulator signaled by the proposed plasmon softening at the CDW wave vector. Using high-resolution electron energy loss spectroscopy, we report a systematic study of the temperature-dependent plasmon behaviors of 1T-TiSe_{2}. We unambiguously resolve the plasmon from phonon modes, revealing the existence of Landau damping to the plasmon at finite momentums, which does not support the plasmon softening picture for exciton condensation. Moreover, we discover that the plasmon lifetime at zero momentum responds dramatically to the band gap evolution associated with the CDW transition. The interband transitions near the Fermi energy in the normal phase are demonstrated to serve as a strong damping channel of plasmons, while such a channel in the CDW phase is suppressed due to the CDW gap opening, which results in the dramatic tunability of the plasmon in semimetals or small-gap semiconductors.

16.
Phys Rev Lett ; 127(18): 186802, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34767385

RESUMO

Nodal-line semimetals (NLSMs), a large family of new topological phases of matter with continuous linear band crossing points in the momentum space, attract considerable attention. Here, we report the direct observation of plasmons originating from topological nodal-line states in a prototypical NLSM ZrSiS by high-resolution electron energy loss spectroscopy. There exist three temperature-independent plasmons with energies ranging from the near- to the mid-infrared frequencies. With first-principles calculations of a slab model, these plasmons can be ascribed to the correlations of electrons in the bulk nodal lines and their projected surface states, dubbed nodal-line plasmons. An anomalous surface plasmon has higher excitation energy than the bulk plasmon due to the larger contribution from the nodal-line projected surface states. This work reveals the novel plasmons related to the unique nodal-line states in a NLSM.

17.
Nat Commun ; 12(1): 5926, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34635672

RESUMO

Enormous enhancement of superconducting pairing temperature (Tg) to 65 K in FeSe/SrTiO3 has made it a spotlight. Despite the effort of interfacial engineering, FeSe interfaced with TiOx remains the unique case in hosting high Tg, hindering a decisive understanding on the general mechanism and ways to further improving Tg. Here we constructed a new high-Tg interface, single-layer FeSe interfaced with FeOx-terminated LaFeO3. Large superconducting gap and diamagnetic response evidence that the superconducting pairing can emerge near 80 K, highest amongst all-known interfacial superconductors. Combining various techniques, we reveal interfacial charge transfer and strong interfacial electron-phonon coupling (EPC) in FeSe/LaFeO3, showing that the cooperative pairing mechanism works beyond FeSe-TiOx. Intriguingly, the stronger interfacial EPC than that in FeSe/SrTiO3 is likely induced by the stronger interfacial bonding in FeSe/LaFeO3, and can explain the higher Tg according to recent theoretical calculations, pointing out a workable route in designing new interfaces to achieve higher Tg.

18.
Mar Pollut Bull ; 168: 112403, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33975158

RESUMO

The Beibu Gulf is an important passageway between China and the Association of Southeast Asian Nations, where there has been an increase in pollution of heavy metals (HMs). High concentrations of Pb, Cr, Cd, Cu, Zn, As, and Hg in surface sediment were found in Qinzhou Bay, Fangchenggang, and other coastal areas. Stochastic geo-accumulation analyses identified the pollution to be "uncontaminated"; however, it had an 18% probability of deterioration. The Cd, Hg, and As pollution were relatively serious. Principal component analysis, positive matrix factor model, and mercury isotopes demonstrated that the HMs could mainly be attributed to industrial sources including petrochemical, coal-fired, metal and metalloid processing, leather tanning, and human activities: anthropogenic sources accounted for approximately 70% of all the contaminations. This study demonstrates the contribution of terrigenous input to HMs even at a low level and provides basic data for the coordinated development of land and marine resources.


Assuntos
Metais Pesados , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análise
19.
Environ Sci Pollut Res Int ; 28(35): 48556-48568, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33909249

RESUMO

This study proposes a new process to synthesize zero-valent iron/biochar (Fe0-BC) by carbothermal reduction using wood waste and iron mud as raw materials under different temperature. The characterization results showed that the Fe0-BC synthesized at 1200 °C (Fe0-BC-1200) possessed favorable adsorption capacity with the specific surface area of 103.18 m2/g and that the zero-valent iron (Fe0) particles were uniformly dispersed on the biochar surface. The removal efficiency of rhodamine B (RB) was determined to evaluate the performance of the prepared Fe0-BC. Fe0-BC-1200 presented the best performance on RB removal, which mainly ascribes to that more Fe0 particles generated at higher temperature. The equilibrium adsorption capacity reached 49.93 mg/g when the initial RB concentration and the Fe0-BC-1200 dosage were 100 mg/L and 2 g/L, respectively, and the pseudo-second-order model was suitable to fit the removal experimental data. LCMC and XRD analyses revealed that the removal mechanism included the physical adsorption of biochar and the redox reaction of Fe0. Moreover, copper existing in the iron mud was also reduced to Cu0, which was beneficial to catalyze the oxidation of iron; the degradation of RB was promoted at the same time.


Assuntos
Ferro , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Rodaminas , Poluentes Químicos da Água/análise , Madeira/química
20.
Nat Commun ; 12(1): 2447, 2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-33907193

RESUMO

The d-band-filling of transition metals in complex oxides plays an essential role in determining their structural, electronic and magnetic properties. Traditionally, at the oxide heterointerface, band-filling control has been achieved via electrostatic modification in the structure of field-effect transistors or electron transfer, which is limited to the quasi-two-dimension at the interface. Here we report a three-dimensional (3D) band-filling control by changing the local lattice coordination in a designed oxide heterostructure. At the LaCoO3/LaTiO3 heterointerface, due to the Fermi level mismatch, electrons transfer from LaTiO3 to LaCoO3. This triggers destabilisation of the CoO6 octahedrons, i.e. the formation of lattice configurations with a reduced Co valence. The associated oxygen migration results in the 3D topotactic phase transition of LaCoO3. Tuned by the thickness of LaTiO3, different crystalline phases and band-fillings of Co occur, leading to the emergence of different magnetic ground states.

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