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1.
Materials (Basel) ; 17(13)2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38998254

RESUMO

Ni-Mn-Sn-based ferromagnetic shape memory alloys (FSMAs) are multifunctional materials that are promising for solid-state refrigeration applications based on the magnetocaloric effect (MCE) and elastocaloric effect (eCE). However, a combination of excellent multi-caloric properties, suitable operating temperatures, and mechanical properties cannot be well achieved in these materials, posing a challenge for their practical application. In this work, we systematically study the phase transformations and magnetic properties of Ni50-xMn38Sn12Cux (x = 0, 2, 3, 4, 5, and 6) and Ni50-yMn38Sn12Fey (y = 0, 1, 2, 3, 4, and 5) alloys, and the magnetic-structural phase diagrams of these alloy systems are reported. The influences of the fourth-element doping on the phase transitions and magnetic properties of the alloys are elucidated by first-principles calculations. This work demonstrates that the fourth-element doping of Ni-Mn-Sn-based FSMA is effective in developing multicaloric refrigerants for practical solid-state refrigeration.

2.
Quant Imaging Med Surg ; 14(6): 3901-3913, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38846285

RESUMO

Background: Previous studies have confirmed that malignant transformation of dysplastic nodule (DN) into hepatocellular carcinoma (HCC) is accompanied by reduction of iron content in nodules. This pathological abnormality can serve as the basis for magnetic resonance imaging (MRI). This study was designed to identify the feasibility of iterative decomposition of water and fat with echo asymmetry and least squares estimation-iron quantitative (IDEAL-IQ) measurement to distinguish early hepatocellular carcinoma (eHCC) from DN. Methods: We reviewed MRI studies of 35 eHCC and 23 DN lesions (46 participants with 58 lesions total, 37 males, 9 females, 31-80 years old). The exams include IDEAL-IQ sequence and 3.0T MR conventional scan [including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and Gadopentic acid (Gd-GDPA)-enhanced]. Then, 3 readers independently diagnosed eHCC, DN, or were unable to distinguish eHCC from DN using conventional MRI (CMRI), and then assessed R2* value of nodules [R2* value represents the nodule iron content (NIC)] and R2* value of liver background [R2* value represents the liver background iron content (LBIC)] with IDEAL-IQ. Statistical analysis was conducted using the t-test for comparison of means, the Mann-Whitney test for comparison of medians, the chi-square test for comparison of frequencies, and diagnostic efficacy was evaluated by using receiver operating characteristic (ROC) curve. Results: This study evaluated 35 eHCC participants (17 males, 6 females, 34-81 years old, nodule size: 10.5-27.6 mm, median 18.0 mm) and 23 DN participants (20 males, 3 females, 31-76 years old, nodule size: 16.30±4.095 mm). The NIC and ratio of NIC to LIBC (NIC/LBIC) of the eHCC group (35.926±12.806 sec-1, 0.327±0.107) was lower than that of the DN group (176.635±87.686 sec-1, 1.799±0.629) (P<0.001). Using NIC and NIC/LBIC to distinguish eHCC from DN, the true positive/false positive rates were 91.3%/94.3% and 87.0%/97.1%, respectively. The rates of CMRI, NIC and NIC/LBIC in diagnosis of eHCC were 77.1%, and 94.3%, 97.1%, respectively, and those of DN were 65.2%, 91.3%, and 87.0%, respectively. The diagnosis rate of eHCC and DN by CMRI was lower than that of NIC and NIC/LBIC (eHCC: P=0.03, 0.04, DN: P=0.02, 0.04). Conclusions: Using IDEAL-IQ measurement can distinguish DN from eHCC.

3.
Nanomaterials (Basel) ; 14(12)2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38921869

RESUMO

Shear banding is much dependent on the glass-glass interfaces (GGIs) in metallic nanoglasses (NGs). Nevertheless, the current understanding of the glass phase of GGIs is not well established for controlling the shear banding in NGs. In this study, Co-P NGs are investigated by molecular dynamics simulations to reveal the phenomenon of elemental segregation in the GGI regions where the content of Co is dominant. Specifically, Co segregation results in the formation of GGIs, whose atomic structures are comparatively less dense than those present in the interiors of glassy grains. It is suggested that the Co segregation significantly reduces the shear resistance of GGIs. Thus, such compositional heterogeneity influences the mechanical properties of Co-P NGs. Particularly, shear banding is much altered through enhancing the Co segregation in the GGI regions, which leads to improvements in the ductility of Co-P NGs. This study advances knowledge of the formation of the GGI phase in NGs, which could enable GGI engineering in enhancing the mechanical properties of NGs.

4.
Sci Rep ; 14(1): 7458, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38548876

RESUMO

The glass-glass interfaces (GGIs) are in a unique glass phase, while current knowledge on the interfacial phase has not completely established to explain the unprecedented improvements in the ductility of metallic nanoglasses (NGs). In this work, Co-P NGs prepared through the pulse electrodeposition are investigated, whose GGI regions clearly show elemental segregation with chemical composition dominated by element Co. Such compositional heterogeneity is further verified by molecular dynamics (MD) simulation on the formation of GGIs in Co-P NGs and atomic structures of GGIs with Co segregation are found to be less dense than those of glassy grains. More importantly, Co segregation at GGIs is closely related to the improved ductility observed in Co-P NGs, as demonstrated by nanoindentation measurements and MD simulations. This work facilitates the understanding on the relations between compositional heterogeneity and improved ductility as observed in Co-P NGs, and thus opens a new window for controlling the mechanical properties of NGs through GGI engineering.

5.
Quant Imaging Med Surg ; 14(1): 1010-1021, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38223080

RESUMO

Background: Pulmonary nodular consolidation (PN) and pulmonary cavity (PC) may represent the two most promising imaging signs in differentiating multidrug-resistant (MDR)-pulmonary tuberculosis (PTB) from drug-sensitive (DS)-PTB. However, there have been concerns that literature described radiological feature differences between DS-PTB and MDR-PTB were confounded by that MDR-PTB cases tend to have a longer history. This study seeks to further clarify this point. Methods: All cases were from the Guangzhou Chest Hospital, Guangzhou, China. We retrieved data of consecutive new MDR cases [n=46, inclusive of rifampicin-resistant (RR) cases] treated during the period of July 2020 and December 2021, and according to the electronic case archiving system records, the main PTB-related symptoms/signs history was ≤3 months till the first computed tomography (CT) scan in Guangzhou Chest Hospital was taken. To pair the MDR-PTB cases with assumed equal disease history length, we additionally retrieved data of 46 cases of DS-PTB patients. Twenty-two of the DS patients and 30 of the MDR patients were from rural communities. The first CT in Guangzhou Chest Hospital was analysed in this study. When the CT was taken, most cases had anti-TB drug treatment for less than 2 weeks, and none had been treated for more than 3 weeks. Results: Apparent CT signs associated with chronicity were noted in 10 cases in the DS group (10/46) and 9 cases in the MDR group (10/46). Thus, the overall disease history would have been longer than the assumed <3 months. Still, the history length difference between DS patients and MDR patients in the current study might not be substantial. The lung volume involvement was 11.3%±8.3% for DS cases and 8.4%±6.6% for MDR cases (P=0.022). There was no statistical difference between DS cases and MDR cases both in PN prevalence and in PC prevalence. For positive cases, MDR cases had more PN number (mean of positive cases: 2.63 vs. 2.28, P=0.38) and PC number (mean of positive cases: 2.14 vs. 1.38, P=0.001) than DS cases. Receiver operating characteristic curve analysis shows, PN ≥4 and PC ≥3 had a specificity of 86% (sensitivity 25%) and 93% (sensitivity 36%), respectively, in suggesting the patient being a MDR cases. Conclusions: A combination of PN and PC features allows statistical separation of DS and MDR cases.

6.
Quant Imaging Med Surg ; 14(1): 1039-1060, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38223121

RESUMO

Tuberculosis (TB) remains one of the major infectious diseases in the world with a high incidence rate. Drug-resistant tuberculosis (DR-TB) is a key and difficult challenge in the prevention and treatment of TB. Early, rapid, and accurate diagnosis of DR-TB is essential for selecting appropriate and personalized treatment and is an important means of reducing disease transmission and mortality. In recent years, imaging diagnosis of DR-TB has developed rapidly, but there is a lack of consistent understanding. To this end, the Infectious Disease Imaging Group, Infectious Disease Branch, Chinese Research Hospital Association; Infectious Diseases Group of Chinese Medical Association of Radiology; Digital Health Committee of China Association for the Promotion of Science and Technology Industrialization, and other organizations, formed a group of TB experts across China. The conglomerate then considered the Chinese and international diagnosis and treatment status of DR-TB, China's clinical practice, and evidence-based medicine on the methodological requirements of guidelines and standards. After repeated discussion, the expert consensus of imaging diagnosis of DR-PB was proposed. This consensus includes clinical diagnosis and classification of DR-TB, selection of etiology and imaging examination [mainly X-ray and computed tomography (CT)], imaging manifestations, diagnosis, and differential diagnosis. This expert consensus is expected to improve the understanding of the imaging changes of DR-TB, as a starting point for timely detection of suspected DR-TB patients, and can effectively improve the efficiency of clinical diagnosis and achieve the purpose of early diagnosis and treatment of DR-TB.

7.
Curr Med Sci ; 43(6): 1195-1200, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38153629

RESUMO

OBJECTIVE: This study aimed to investigate the potential mechanisms by which lysyl oxidase like 3 (LOXL3) affects the autophagy in chondrocytes in osteoarthritis (OA), specifically through the activation of mammalian target of rapamycin complex 1 (mTORC1). METHODS: To establish an OA model, rats underwent anterior cruciate ligament transection (ACLT). Chondrocytes were isolated from cartilage tissues and cultured. Western blotting was performed to assess the expression of LOXL3, Rheb, phosphorylation of p70S6K (p-p70S6K, a downstream marker of mTORC1), and autophagy markers. The autophagy of chondrocytes was observed using an immunofluorescence assay. RESULTS: The expression levels of both LOXL3 and Rheb proteins were upregulated in chondrocytes isolated from the OA model cartilage, in comparison to those from the normal cartilage. The silencing of LOXL3 resulted in a decrease in the protein levels of Rheb and p-p70S6K, as well as an increase in the expression of autophagy-related proteins. Additionally, the effect of LOXL3 could be reversed through the silencing of Rheb. The results of the immunofluorescence assay confirmed the impact of LOXL3 and Rheb on chondrocyte autophagy. CONCLUSION: LOXL3 inhibits chondrocyte autophagy by activating the Rheb and mTORC1 signaling pathways.


Assuntos
Aminoácido Oxirredutases , Condrócitos , Osteoartrite , Animais , Ratos , Autofagia/genética , Mamíferos , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Osteoartrite/genética , Proteína Enriquecida em Homólogo de Ras do Encéfalo/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Aminoácido Oxirredutases/genética
8.
Nanomicro Lett ; 16(1): 29, 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-37994956

RESUMO

The laminated transition metal disulfides (TMDs), which are well known as typical two-dimensional (2D) semiconductive materials, possess a unique layered structure, leading to their wide-spread applications in various fields, such as catalysis, energy storage, sensing, etc. In recent years, a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption (EMA) has been carried out. Therefore, it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application. In this review, recent advances in the development of electromagnetic wave (EMW) absorbers based on TMDs, ranging from the VIB group to the VB group are summarized. Their compositions, microstructures, electronic properties, and synthesis methods are presented in detail. Particularly, the modulation of structure engineering from the aspects of heterostructures, defects, morphologies and phases are systematically summarized, focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance. Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.

9.
Adv Healthc Mater ; 12(30): e2302181, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37673039

RESUMO

The pathophysiology of osteoarthritis (OA) is closely linked to autophagy abnormalities in articular chondrocytes, the sole mature cell type in healthy cartilage. Nevertheless, the precise molecular mechanism remains uncertain. Previous research has demonstrated that leptin activates mTORC1 , thereby inhibiting chondrocyte autophagy during the progression of OA. In this study, it is demonstrated that the presence of leptin induces a substantial increase in the expression of STAT3, leading to a notable decrease in REDD1 expression and subsequent phosphorylation of p70S6K, a recognized downstream effector of mTORC1. Conversely, inhibition of leptin yields contrasting effects. Additionally, the potential advantages of utilizing a sustained intra-articular release of a leptin inhibitor (LI) via an injectable, thermosensitive poly(D,L-lactide)-poly(ethylene glycol)-poly(D,L-lactide) (PDLLA-PEG-PDLLA: PLEL) hydrogel delivery system for the purpose of investigating its impact on cartilage repair are explored. The study conducted on LI-loaded PLEL (PLEL@LI) demonstrates remarkable efficacy in inhibiting OA and displays encouraging therapeutic advantages in the restoration of subchondral bone and cartilage. These findings establish a solid foundation for the advancement of a pioneering treatment approach utilizing PLEL@LI for OA.


Assuntos
Cartilagem Articular , Osteoartrite , Humanos , Autofagia , Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Preparações de Ação Retardada/farmacologia , Hidrogéis/farmacologia , Leptina/antagonistas & inibidores , Leptina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Osteoartrite/tratamento farmacológico , Fator de Transcrição STAT3/metabolismo , Regeneração
10.
Materials (Basel) ; 16(16)2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37630016

RESUMO

Solid-state refrigeration technology is expected to replace conventional gas compression refrigeration technology because it is environmentally friendly and highly efficient. Among various solid-state magnetocaloric materials, Ni-Mn-based ferromagnetic shape memory alloys (SMAs) have attracted widespread attention due to their multifunctional properties, such as their magnetocaloric effect, elastocaloric effect, barocaloric effect, magnetoresistance, magnetic field-induced strain, etc. Recently, a series of in-depth studies on the thermal effects of Ni-Mn-based magnetic SMAs have been carried out, and numerous research results have been obtained. It has been found that poor toughness and cyclic stability greatly limit the practical application of magnetic SMAs in solid-state refrigeration. In this review, the influences of element doping, microstructure design, and the size effect on the strength and toughness of Ni-Mn-based ferromagnetic SMAs and their underlying mechanisms are systematically summarized. The pros and cons of different methods in enhancing the toughness of Ni-Mn-based SMAs are compared, and the unresolved issues are analyzed. The main research directions of Ni-Mn-based ferromagnetic SMAs are proposed and discussed, which are of scientific and technological significance and could promote the application of Ni-Mn-based ferromagnetic SMAs in various fields.

11.
Phys Chem Chem Phys ; 25(31): 20854-20862, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37522224

RESUMO

Dielectric materials play an important role in devices for energy conversion and storage. Based on first-principles calculations, novel two-dimensional Janus GaOClX (X = F, Br, and I) monolayers with superior energy storage properties are predicted. They are indirect-bandgap semiconductors with bandgaps in the range of 2.18-4.36 eV, and possess anisotropic carrier mobility, strong mechanical flexibility, and excellent out-of-plane piezoelectricity. More importantly, it is found that the GaOCl monolayer and Janus GaOClX monolayers could exhibit an ultrahigh energy storage density (as high as 893.32 J cm-3) comparable to those of electrochemical supercapacitors and batteries, unparalleled by other dielectric materials reported to date. This work opens up a new window in searching for novel dielectric materials, which could be used in dielectric capacitors with superior energy storage density and power density, excellent efficiency and thermal stability.

12.
Adv Mater ; 35(36): e2210829, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37257887

RESUMO

Rapid advances in the engineering application prospects of metal-organic framework (MOF) materials necessitate an urgent in-depth understanding of their mechanical properties. This work demonstrates unprecedented recoverable elastic deformation of Ni-tetraphenylporphyrins (Ni-TCPP) MOF nanobelts with a tensile strain as high as 14%, and a projected yield strength-to-Young's modulus ratio exceeding the theoretical limit (≈10%) for crystalline materials. Based on first-principles simulations, the observed behavior of MOF crystal can be attributed to the mechanical deformation induced conformation transition and the formation of helical configuration of dislocations under high stresses, arising from their organic ligand building blocks in the crystal structures. The investigations of the mechanical properties along with electromechanical properties demonstrate that MOF materials have exciting application potential for biomechanics integrated systems, flexible electronics, and nanoelectromechanical devices.

13.
Nanomaterials (Basel) ; 12(13)2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35807993

RESUMO

The present work reports the interfacial behaviors and mechanical properties of AlCoCrFeNi high-entropy alloy (HEA) reinforced aluminum matrix composites (AMCs) based on first-principles calculations. It is found the stability of HEA-reinforced AMCs is strongly dependent on the local chemical compositions in the interfacial regions, i.e., those regions containing more Ni atoms (>25%) or fewer Al atoms (<20%) render more stable interfaces in the HEA-reinforced AMCs. It is calculated that the interfacial energy of Al(001)/Al20Co19Cr19Fe19Ni19(001) interfaces varies from −0.242 eV/Å2 to −0.192 eV/Å2, suggesting that the formation of interfaces at (100) atomic plane is energetically favorable. For those constituent alloy elements presented at the interfaces, Ni could stabilize the interface whereas Al tends to deteriorate the stability of interface. It is determined that although the HEA-reinforced AMCs have less yield strength compared to aluminum, their Young's modulus is enhanced from 69 GPa for pure Al to 134 GPa. Meanwhile, the meaningful plasticity under tension could also be improved, which are related to the chemical compositions at the interfaces. The results presented in this work could facilitate the designs of compositions and interfacial behaviors of HEA-reinforced AMCs for structural applications.

14.
Nanoscale ; 14(31): 11369-11377, 2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-35894834

RESUMO

Two-dimensional (2D) materials with excellent properties are emerging as promising candidates in electronics and spintronics. In this work, a novel GaOCl monolayer is proposed and studied systematically based on first-principles calculations. With excellent thermal and dynamic stability at room temperature, its wide direct bandgap (4.46 eV) can be further modulated under applied strains. The 2D semiconductor exhibits high mechanical flexibility, and anisotropy in Poisson's ratio and carrier mobilities, endowing it with a broad spectrum of electronic and optoelectronic applications. More importantly, the GaOCl monolayer has spontaneous magnetization induced by hole doping and shows outstanding multidirectional piezoelectricity, which are comparable with those of either magnetic or piezoelectric 2D materials. Our calculations indicate that the GaOCl monolayer with wide bandgaps and tunable piezoelectricity and ferromagnetism could be promising for applications in multifunctional integrated nano-devices with high performance.

15.
Nanomicro Lett ; 14(1): 80, 2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-35333993

RESUMO

With rapid development of 5G communication technologies, electromagnetic interference (EMI) shielding for electronic devices has become an urgent demand in recent years, where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role. Meanwhile, the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications. Hitherto, a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed. In this review, we not only introduce the recent development of flexible EMI shielding materials, but also elaborate the EMI shielding mechanisms and the index for "green EMI shielding" performance. In addition, the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized. Finally, we propose several possible research directions for flexible EMI shielding materials in near future, which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.

16.
Phys Chem Chem Phys ; 24(14): 8371-8377, 2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35332903

RESUMO

InSeBr-Type monolayers, ternary In(Se,S)(Br,Cl) compounds, are typical two-dimensional (2D) Janus materials and can be exfoliated from their bulk crystals. The structural stability, electronic properties, mechanical flexibility, and intrinsic piezoelectricity of these InSeBr-type 2D Janus monolayers are comprehensively investigated by first-principles calculations. Our calculations show that the stable InSeBr-type monolayers exhibit ultrahigh mechanical flexibility with low Young's moduli. Due to the amazing flexibility of the InSeBr monolayer with an ultra-low Young's modulus of 0.81 N m-1, the piezoelectric strain coefficient d11 can reach 103 pm V-1 orders of magnitude (around 2361-3224 pm V-1), which is larger than those of reported 2D materials and even superior to those of conventional perovskite bulk materials. Such a superior piezoelectric response of InSeBr-type monolayers could facilitate their practical applications in sensors and energy harvesters.

17.
Quant Imaging Med Surg ; 11(2): 714-724, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33532271

RESUMO

BACKGROUND: Acquired immunodeficiency syndrome-associated Kaposi's sarcoma (AIDS-KS) was the first malignant neoplasm to be described as being related to AIDS. The lungs are the most common visceral site of AIDS-KS. This study aimed to analyze the computed tomography (CT) manifestations of pulmonary involvement in AIDS-KS. METHODS: Twenty-nine male patients were enrolled in this retrospective study. Imaging evaluation parameters included lesion distribution, the flame sign, interlobular septal thickening, peribronchovascular interstitium thickening, ground-glass opacity (GGO), dilated blood vessels in lesions, and pleural effusion. RESULTS: A peribronchovascular distribution was observed in all patients, predominantly in the lower lobes. Of the patients, 58.62% (17/29) exhibited the flame sign, 75.86% (22/29) had interlobular septal thickening, 72.41% (21/29) had peribronchovascular interstitium thickening, 82.76% (24/29) had GGO, and 34.48% (10/29) had pleural effusion. Enlarged lymph nodes with a short-axis diameter >1.0 cm were found in 41.38% (12/29) of the patients. Of the 12 patients who underwent contrast-enhanced CT (CECT), 90.91% (11/12) had dilated blood vessels, and nodules, consolidations, and lymph nodes were observed to be strongly enhanced. Intrapulmonary lesions decreased in size or number after appropriate treatment during follow-up. CONCLUSIONS: Common CT manifestations of pulmonary AIDS-KS include the flame sign, peribronchovascular distribution, peribronchovascular interstitium thickening, interlobular septa thickening, GGO, dilated blood vessel, and strong enhancement of nodules, consolidations, and lymph nodes. It is helpful to follow up the therapeutic effect of pulmonary AIDS-KS by chest CT.

18.
Phys Chem Chem Phys ; 23(5): 3637-3645, 2021 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-33524094

RESUMO

Due to their broken out-of-plane inversion symmetry, Janus two-dimensional (2D) materials exhibit some exceptional and interesting physical properties and have recently attracted increasing attention. Herein, based on first-principles calculations, we propose a series of Janus 2D titanium nitride halide TiNX0.5Y0.5 (X, Y = F, Cl, or Br, and X ≠ Y) monolayers constructed from 2D ternary compounds TiNX (X = F, Cl, or Br), where the halogen atoms X or Y are located on each side of the monolayer, respectively. Our calculations confirm that the Janus monolayers are both dynamically and thermally stable. As compared with those of perfect TiNX monolayers, the band-structure changes of Janus TiNX0.5Y0.5 monolayers are very limited and the corresponding bandgaps only increase by about 0.1-0.2 eV. Meanwhile, the Janus TiNX0.5Y0.5 monolayers show remarkable out-of-plane piezoelectricity by virtue of their broken centrosymmetry. The calculated out-of-plane piezoelectric coefficient d31 is as high as 0.34 pm V-1, which is larger than those of most 2D piezoelectric materials reported previously. In addition, it is found that the formation of Janus structures could effectively improve the carrier mobility. The hole mobilities along the x-direction (y-direction) of Janus TiNF0.5Cl0.5 and TiNF0.5Br0.5 monolayers reach as high as 5402 (5118) and 5538 (4135) cm2 V-1 s-1 at 300 K, respectively, which is almost twice as large as those of perfect TiNX monolayers. The giant out-of-plane piezoelectricity and high carrier mobility of Janus TiNX0.5Y0.5 monolayers suggest that these novel 2D materials could be promising for applications in electronic and piezoelectric devices.

19.
Front Med (Lausanne) ; 8: 686878, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35096849

RESUMO

Objective: The pulmonary sequelae of coronavirus disease 2019 (COVID-19) have not been comprehensively evaluated. We performed a follow-up study analyzing chest computed tomography (CT) findings of COVID-19 patients at 3 and 6 months after hospital discharge. Methods: Between February 2020 and May 2020, a total of 273 patients with COVID-19 at the Shenzhen Third People's Hospital were recruited and followed for 6 months after discharge. Chest CT scanning was performed with the patient in the supine position at end-inspiration. A total of 957 chest CT scans was obtained at different timepoints. A semi-quantitative score was used to assess the degree of lung involvement. Results: Most chest CT scans showed bilateral lung involvement with peripheral location at 3 and 6 months follow-up. The most common CT findings were ground-glass opacity and parenchymal band, which were found in 136 (55.3%) and 94 (38.2%) of the 246 patients at 3 months follow-up, and 82 (48.2%) and 76 (44.7%) of 170 patients at 6 months follow-up, respectively. The number of lobes involved and the total CT severity score declined over time. The total CT score gradually increased with the increasement of disease severity at both 3 months follow-up (trend test P < 0.001) and 6 months follow-up (trend test P < 0.001). Patients with different disease severity represented diverse CT patterns over time. Conclusions: The most common CT findings were ground-glass opacity and parenchymal bands at the 3 and 6 months follow-up. Patients with different disease severity represent diverse CT manifestations, indicating the necessary for long-term follow-up monitoring of patients with severe and critical conditions.

20.
Phys Chem Chem Phys ; 22(46): 27441-27449, 2020 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-33232408

RESUMO

Low-dimensional materials have aroused widespread interest for their novel and fascinating properties. Based on first-principles calculations, we predict the one-dimensional (1D) InSeI nanochains with van der Waals (vdW) interchain interactions, which could be exfoliated mechanically and kept at steady states at room temperature. Compared with bulk InSeI, the single nanochain InSeI has a larger direct bandgap of 3.15 eV. Its calculated carrier mobility is as high as 54.17 and 27.49 cm2 V-1 s-1 for holes and electrons, respectively, comparable with those of other 1D materials. In addition, a direct-to-indirect bandgap transition is implemented under a small applied strain (∼6%). More importantly, the nanochains are found to be promising candidates for optoelectronic devices since they possess a high absorption coefficient of ∼105 cm-1 in the ultraviolet region. The results thus pave a novel avenue for the applications of InSeI nanochains with excellent thermal stability in nanoelectronic and optoelectronic devices.

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