Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 134
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 119(26): e2121513119, 2022 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-35737832

RESUMEN

Both chronic obstructive pulmonary disease (COPD) and asthma are severe respiratory diseases. Bitter receptor-mediated bronchodilation is a potential therapy for asthma, but the mechanism underlying the agonistic relaxation of airway smooth muscle (ASM) is not well defined. By exploring the ASM relaxation mechanism of bitter substances, we observed that pretreatment with the bitter substances nearly abolished the methacholine (MCh)-induced increase in the ASM cell (ASMC) calcium concentration, thereby suppressing the calcium-induced contraction release. The ASM relaxation was significantly inhibited by simultaneous deletion of three Gαt proteins, suggesting an interaction between Tas2R and AChR signaling cascades in the relaxation process. Biochemically, the Gαt released by Tas2R activation complexes with AChR and blocks the Gαq cycling of AChR signal transduction. More importantly, a bitter substance, kudinoside A, not only attenuates airway constriction but also significantly inhibits pulmonary inflammation and tissue remodeling in COPD rats, indicating its modulation of additional Gαq-associated pathological processes. Thus, our results suggest that Tas2R activation may be an ideal strategy for halting multiple pathological processes of COPD.


Asunto(s)
Asma , Músculo Liso , Enfermedad Pulmonar Obstructiva Crónica , Receptores Acoplados a Proteínas G , Activación Transcripcional , Animales , Asma/genética , Asma/metabolismo , Asma/fisiopatología , Broncodilatadores/farmacología , Calcio/metabolismo , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Miocitos del Músculo Liso/efectos de los fármacos , Miocitos del Músculo Liso/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/genética , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Ratas , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal
2.
Inorg Chem ; 63(19): 8846-8852, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38695272

RESUMEN

Double perovskites (DPs) have attracted attention in the field of luminescence due to their inherent broadband emission of self-trapping excitons. In this work, we choose [(CH3)3NCH2CHCH2]+ and [CH3CHOHCH2NH2]+ as organic cations to synthesize two new organic-inorganic hybrid DPs, [(CH3)3NCH2CHCH2]2KInCl6 (1) and [CH3CHOHCH2NH2]2KInCl6 (2). The [KCl6]3- and [InCl6]3- octahedra are interchangeably connected by sharing two opposite faces, forming a one-dimensional coordination chain. Each K atom coordinates with six chlorine atoms in 1, while it coordinates with two oxygen atoms in addition to the six chlorine atoms in 2. The coordination between ions K and O in compound 2 may have significantly reduced its luminescence. As a result, compound 1 shows bright-yellow light with a quantum yield of more than 90%, while 2 shows weak blue light with a quantum yield of only 0.98%. In addition, different from no phase transition found in 2, 1 undergoes a reversible phase transition at 324/307 K in the heating-cooling cycle. Through structural and spectral analysis and density functional theory calculation, we conclude that the larger degree of [InCl6]3- octahedral distortion and the larger anion distance (In···In) also cause the PLQY of compound 1 to be higher than that of compound 2.

3.
Phytother Res ; 2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38695125

RESUMEN

Osteoarthritis (OA), a joint disease that is associated with inflammatory processes is involved in joint destruction. Scutellarein (Scu), a component of the medicinal herbs Scutellaria barbata D. Don and Erigeron breviscapus (vant) Hand Mass, has anti-inflammatory effects. We explored the role of Scu in the development of OA and the underlying mechanisms. CCK-8 assays, Calcein-AM/PI and EdU staining were used to determine chondrocyte viability after Scu exposure. Western blot, qPCR, as well as ELISA were utilized to measure extracellular matrix (ECM) degradation and inflammation. Immunofluorescence (IF), western blot and luciferase assays were used to examine the NF-kappaB (NF-κB) pathway. Scu interacting proteins were predicted using network pharmacology analysis and molecular docking. X-ray, H&E, Safranin O-Fast Green(S-O), toluidine blue, and immunohistochemistry analysis were used to examine the therapeutic effects of Scu in OA using destabilization of medial meniscus (DMM) models. Scu demonstrated inhibitory effects on ECM degradation and pro-inflammatory factor levels in chondrocytes treated with IL-1ß. Mechanistically, Scu inhibited the IL-1ß-induced activation of the PI3K/Akt/ NF-κB signaling pathway cascades. Furthermore, Scu has been shown to have significant binding capacities to PI3K. Additionally, Scu ameliorated the OA progression in DMM models. Our findings suggest that Scu may contribute to the amelioration of OA progression by targeting the PI3K/Akt/NF-κB signaling pathway, implying Scu possesses promising therapeutic potential for the treatment of OA.

4.
Angew Chem Int Ed Engl ; : e202408247, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38837719

RESUMEN

The construction of mechanically responsive materials with reversible shape-shifting, shape-locking, and stretchability holds promise for a wide range of applications in fields such as soft robotics and flexible electronics. Here, we report novel thermoelastic one-dimensional organic-inorganic hybrids (R/S-Hmpy)PbI3 (Hmpy = 2-hydroxymethyl-pyrrolidinium) to show mechanical responses. The single crystals undergo two phase transitions at 310 K and 380 K. When heated to 380 K, they show shape-shifting and expansion along the b-axis by about 13.4%, corresponding to a larger deformation than that of thermally activated shape memory alloys (8.5%), and exhibit a strong actuation force. During cooling process, the stretched crystal shape maintains and a shape-locking phenomenon occurs, which is lifted when the temperature decreasing to 305 K. Meanwhile, due to the introduction of chiral ions, the thermal switching shows a 10-fold second-order nonlinear switching contrast (common values typically below 3-fold). This study presents a thermoelastic actuator based on shape-shifting and -locking of organic-inorganic hybrids for the first time. The dielectric and nonlinear optical switching properties of organic-inorganic hybrids broaden the range of applications of mechanically responsive crystals.

5.
J Biol Chem ; 298(1): 101516, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34942145

RESUMEN

The thymus is the central immune organ, but it is known to progressively degenerate with age. As thymus degeneration is paralleled by the wasting of aging skeletal muscle, we speculated that the thymus may play a role in muscle wasting. Here, using thymectomized mice, we show that the thymus is necessary for skeletal muscle regeneration, a process tightly associated with muscle aging. Compared to control mice, the thymectomized mice displayed comparable growth of muscle mass, but decreased muscle regeneration in response to injury, as evidenced by small and sparse regenerative myofibers along with inhibited expression of regeneration-associated genes myh3, myod, and myogenin. Using paired box 7 (Pax7)-immunofluorescence staining and 5-Bromo-2'-deoxyuridine-incorporation assay, we determined that the decreased regeneration capacity was caused by a limited satellite cell pool. Interestingly, the conditioned culture medium of isolated thymocytes had a potent capacity to directly stimulate satellite cell expansion in vitro. These expanded cells were enriched in subpopulations of quiescent satellite cells (Pax7highMyoDlowEdUpos) and activated satellite cells (Pax7highMyoDhighEdUpos), which were efficiently incorporated into the regenerative myofibers. We thus propose that the thymus plays an essential role in muscle regeneration by directly promoting satellite cell expansion and may function profoundly in the muscle aging process.


Asunto(s)
Músculo Esquelético , Regeneración , Células Satélite del Músculo Esquelético , Timo , Animales , Diferenciación Celular , Proliferación Celular , Ratones , Desarrollo de Músculos/fisiología , Músculo Esquelético/crecimiento & desarrollo , Músculo Esquelético/metabolismo , Proteína MioD/genética , Proteína MioD/metabolismo , Factor de Transcripción PAX7/genética , Factor de Transcripción PAX7/metabolismo , Regeneración/fisiología , Células Satélite del Músculo Esquelético/citología , Células Satélite del Músculo Esquelético/metabolismo , Timo/metabolismo , Cicatrización de Heridas
6.
Neuroimage ; 281: 120374, 2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-37729795

RESUMEN

The study of neural circuits, which underlies perception, cognition, emotion, and behavior, is essential for understanding the mammalian brain, a complex organ consisting of billions of neurons. To study the structure and function of the brain, in vivo neuronal labeling and imaging techniques are crucial as they provide true physiological information that ex vivo methods cannot offer. In this paper, we present a new strategy for in vivo neuronal labeling and quantification using MRI. We demonstrate the efficacy of this method by delivering the oatp1a1 gene to the target neurons using rAAV2-retro virus. OATP1A1 protein expression on the neuronal membrane increased the uptake of a specific MRI contrast agent (Gd-EOB-DTPA), leading to hyperintense signals on T1W images of labeled neuronal populations. We also used dynamic contrast enhancement-based methods to obtain quantitative information on labeled neuronal populations in vivo.

7.
Chemistry ; 29(18): e202203606, 2023 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-36598368

RESUMEN

The remarkable material stability and structural diversity of two-dimensional (2D) organic-inorganic hybrid perovskites (OIHPs) constitute a vast available library of versatile materials. In particular, ferroelastic property, for which the spontaneous strain can be transformed by applying mechanical stress, is very promising for extensive nanotechnological applications. However, integrating ferroelastic property into 2D OIHPs is still in its infancy. Herein, we designed two new 2D OIHPs (C3 H5 CH2 NH3 )2 [MCl4 ] (M=Mn for 1 and Cd for 2), which undergo reversible ferroelastic phase transitions with an Aizu expression 4/mmmFmmm. The templating influence of the more distorted inorganic framework on the disordering of organic cations and the stronger hydrogen bonds has a key role in the striking improvement of Curie temperature from 246 K in 1 to 273 K in 2. Meanwhile, the minimized alteration of structural motif ensures the well maintaining of the ferroelastic performance in the forms of crystals and thin films, as demonstrated by the identifiable evolution of domain structures. This work will provide a fertile new ground for enlarging the limited number of 2D ferroelastic OIHPs with better practical utility.

8.
Inorg Chem ; 62(41): 16898-16904, 2023 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-37782683

RESUMEN

[(CH3)3P(CH2)2OH]2Cd3(SCN)8 (1) and [(CH3)3P(CH2)2OH]Cd(SCN)3 (2) were obtained with completely different structures and properties under the same synthesis conditions. Compound 1, showing green fluorescence, has a rare three-dimensional 4,6-connected fsh topology having (43.63)2(46.66.83) Schläfli notation, while compound 2 with blue-violet phosphorescence displays a one-dimensional perovskite structure with an infinite {[Cd(SCN)3]-}∞ chain and exhibits both ferroelastic and dielectric switching characteristics.

9.
Inorg Chem ; 62(3): 1279-1285, 2023 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-36609157

RESUMEN

Ferroelastic materials have received special attention because of their great promise for mechanical switches, piezoelectric sensors, and data storage applications. Here, we report a novel ferroelastic semiconducting hybrid organic-inorganic perovskite (C3H7N2S)PbBr3 (1) [(C3H7N2S)+ is 2-amino-2-thiazolinium] with a ferroelastic phase transition at 395 K and an optical band gap of 3.43 eV. 1 has a one-dimensional BaNiO3-type structure and undergoes a high-temperature ferroelastic phase transition with an Aizu notation of mmmF2/m. Meanwhile, 1 exhibits dielectric switch near the phase transition temperature. By introducing the thioether group, the motion of the molecules or ions of 1 is hindered after the sorption of Pd(II) metal ions, which leads to the disappearance of the high-temperature ferroelastic phase transition and dielectric switch. This is the first reported ferroelastic semiconductor material with Pd(II) adsorption property, by studying the influence of Pd(II) adsorption on high-temperature ferroelastic phase transition, it may be enlightening to further uncover the mechanism of phase transition or the origin of ferroelasticity, which represents an important step toward multifunctional applications of lead-hybrid perovskite-based ferroelastic materials.


Asunto(s)
Temperatura , Adsorción , Transición de Fase , Temperatura de Transición
10.
Radiology ; 305(1): 149-159, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35699576

RESUMEN

Background The role of contrast-enhanced US (CEUS) in reducing unnecessary biopsies of thyroid nodules has received little attention. Purpose To construct and externally validate a thyroid imaging reporting and data system (TI-RADS) based on nonenhanced US and CEUS to stratify the malignancy risk of thyroid nodules. Materials and Methods This retrospective study evaluated 756 patients with 801 thyroid nodules who underwent nonenhanced US, CEUS, and fine-needle aspiration and received a final diagnosis from January 2018 to December 2019. Qualitative US features of the thyroid nodules were analyzed with univariable and multivariable logistic regression to construct a CEUS TI-RADS. The CEUS TI-RADS was validated with use of internal cross-validation and external validation. Results A total of 801 thyroid nodules in 590 female (mean age, 44 years ± 13) and 166 male (mean age, 47 years ± 13 [SD]) patients were included. Independent predictive US features included nodule composition at CEUS, echogenicity, nodule shape, nodule margin, echogenic foci, extrathyroidal extension, enhancement direction, peak intensity, and ring enhancement. The CEUS TI-RADS showed a higher area under the receiver operating characteristic curve of 0.93 (95% CI: 0.92, 0.95; P < .001 in comparison with all other systems), a biopsy yield of malignancy of 66% (157 of 239 nodules), and an unnecessary biopsy rate of 34% (82 of 239 nodules). In the external validation, the area under the receiver operating characteristic curve, biopsy yield of malignancy, and unnecessary biopsy rate of CEUS TI-RADS were 0.89 (95% CI: 0.84, 0.92), 61% (65 of 106 nodules), and 39% (41 of 106 nodules) for the first external validation set and 0.90 (95% CI: 0.85, 0.94), 57% (56 of 99 nodules), and 43% (43 of 99 nodules) for the second external validation set. Conclusion A contrast-enhanced US (CEUS) thyroid imaging reporting and data system was created with thyroid nodule malignancy risk stratification according to the simplified regression coefficients of nonenhanced US and qualitative features of CEUS. Clinical trials registration no. ChiCTR2000028712 Published under a CC BY 4.0 license. Online supplemental material is available for this article.


Asunto(s)
Nódulo Tiroideo , Adulto , Biopsia con Aguja Fina , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Sensibilidad y Especificidad , Nódulo Tiroideo/diagnóstico por imagen , Nódulo Tiroideo/patología , Ultrasonografía/métodos
11.
Inorg Chem ; 61(32): 12856-12862, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35914248

RESUMEN

Layered hybrid perovskites, due to their broad application potential in optical, electrical, and luminescence fields, are attracting increasing attention. Herein, we report two novel two-dimensional hybrid organic-inorganic perovskites [C5H10N2S]PbBr4 (1) and [C5H10N2S]PbI4 (2) ([C5H10N2S]2+ is 3-ethylaminothiazolium), which possess phase transition and semiconductor properties. Intriguingly, 1 has semiconductor properties with an optical band gap of 2.70 eV and a photocurrent to dark current ratio of 50 for the photoresponse. By varying the halogen, the band gap of 2 is significantly reduced to 2.06 eV and the photocurrent to dark current ratio of the photoresponse reaches 104. Moreover, compounds 1 and 2 are able to adsorb Pd(II) resulting from the presence of -SH groups in the cation. The adsorption of Pd(II) can turn a semiconductor into an insulator, weaken the fluorescence intensity, and cause the phase transition behavior to disappear. This work has remarkable implications for the continuous development of hybrid perovskites with phase transitions, metal adsorption, and semiconductor properties.

12.
BMC Geriatr ; 22(1): 611, 2022 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-35870888

RESUMEN

BACKGROUND: Falls are common among adults aged 60 years and older because of physiological changes. Most falls in older adults occur most often at home. Coupled with the lack of awareness and knowledge of preventing falls, the proportion of injuries and deaths among older adults due to falls is increasing yearly. Our study developed a WeChat mini-program for urban elderly to implement teach-back health education (TBHE) that a repeated cycle process of health education, assessment, and re-education in preventing falls at home. OBJECTIVES: This study aimed to evaluate the application effect of the TBHE-based WeChat mini-program on health education knowledge for fall prevention at home for urban older adults. DESIGN: A single-blinded, two-arm parallel-group, randomized controlled trial was conducted. SETTING: Three residential communities, named Hot Spring Apartment, Hualinyuan, and Dongtang Community in Gulou District, Fuzhou, China. PARTICIPANTS: Participants were older adults recruited from communities in Fuzhou from January to March 2021. METHODS: Fifty-nine participants agreed to participate and were assigned randomly to the intervention group (n = 29) or the control group receiving traditional health education (n = 30). Each participant in the intervention group received twice a week for a total of 8 weeks of health education interventions performed by the first author that she is intervenor according to specific themes. The trial statistician, recruiters, and participants were blinded to group allocation. The intervenor (first author) was blinded to the study hypotheses. To evaluate the effects of the intervention, we assessed participants' knowledge total score and scores of physiology and disease; drug application; mental, cognitive, and spiritual well-being; lifestyle; and house environment at baseline and 1-week post-intervention and compared scores between two groups. A two-way repeated-measures analysis of variance was conducted to examine the effects of time, group, and their interaction. RESULTS: There was a significant difference in knowledge of house environment (p = 0.003) between the two groups. Within groups, total and five dimensions knowledge scores had a significant difference (p < 0.001). Moreover, interaction effects were significant on drug application (p = 0.012) and mental, cognitive, and spiritual well-being (p = 0.015). CONCLUSIONS: The TBHE can improve knowledge on fall prevention at home among urban older adults. The TBHE based on the WeChat mini-program could enhance the efficiency and effectiveness of being educated among urban older adults. TRIAL REGISTRATION: Chinese Clinical Trial Register: ChiCTR2100052946 ; reg date: 06/11/2021.


Asunto(s)
Terapia por Ejercicio , Educación en Salud , Anciano , China/epidemiología , Terapia por Ejercicio/métodos , Femenino , Humanos , Persona de Mediana Edad
13.
BMC Public Health ; 22(1): 2071, 2022 11 12.
Artículo en Inglés | MEDLINE | ID: mdl-36371174

RESUMEN

BACKGROUND: Falls are one of the main reasons for mortality and morbidity in older adults. However, despite adoption of prevention strategies, the number of falls in older adults has not declined. This study aimed to develop a questionnaire to assess fall prevention knowledge and explore associated factors among Chinese community-dwelling older adults. METHODS: The Home-Based Fall Prevention Knowledge (HFPK) questionnaire was developed by Delphi expert consultation. We tested the internal consistency, reliability, and content validity of the HFPK. A total of 374 community-dwelling older adults participated in this study. The HFPK was used to assess their fall prevention knowledge. RESULTS: After being evaluated by 15 experts, the item content validity index ranged from 0.867 to 1, and the scale content validity index was 0.985, which met the criterion for content validity. Cronbach's α coefficient was 0.933, which satisfied the reliability criterion. Stepwise linear regression analysis showed that fall prevention knowledge was significantly associated with having higher education, being female, having a higher monthly income, people who were public officials before retirement, and having fewer children (p < 0.05). CONCLUSION: Fall prevention knowledge should be improved among older males and those with lower education, lower monthly income, people who were not public officials before retirement, and more children.


Asunto(s)
Accidentes por Caídas , Vida Independiente , Masculino , Niño , Humanos , Femenino , Anciano , Accidentes por Caídas/prevención & control , Reproducibilidad de los Resultados , Encuestas y Cuestionarios , Análisis de Regresión
14.
Inorg Chem ; 60(14): 10642-10647, 2021 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-34236841

RESUMEN

Two-dimensional organic-inorganic hybrid perovskites (OIHPs) have gained attention as a result of their flexibility and adjustability of the structure. However, the large band gap of two-dimensional perovskites limits their application in the photoelectric field. In the present work, we report a two-dimensional organic-inorganic hybrid compound of (C7H18N2)PbI4 (1) with a narrow band gap, which consists of [PbI4]2-n layers and N-(2-aminoethyl)piperidinium cations. 1 exhibits semiconducting properties with a narrow optical band gap of ∼2.02 eV and a photoelectric response with a ratio of photocurrent to dark current of ∼100. In addition, it exhibits a reversible solid-state phase transition at 228 K. This finding should inspire research into more 2D layered OIHPs with the combination of phase transition and semiconductor properties.

15.
Chemistry ; 26(62): 14124-14129, 2020 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-32428259

RESUMEN

In the last decade, hybrid materials have received widespread attention. In particular, hybrid lead halide perovskite-type semiconductors are very attractive owing to their great flexibility in band gap engineering. Here, by using precise molecular modifications, three one-dimensional perovskite-type semiconductor materials are designed and obtained: [Me3 PCH2 X][PbBr3 ] (X=H, F, and Cl for compounds 1, 2, and 3, respectively). The introduction of a heavier halogen atom (F or Cl) to [Me4 P]+ increases the potential energy barrier required for the tumbling motion of the cation, hence achieving the transformation of the phase transition temperature from low temperature (192 K) to room temperature (285 K) and high temperature (402.3 K). Moreover, the optical band gaps reveal a broadening trend with 3.176 eV, 3.215 eV, and 3.376 eV along the H→F→Cl series, which is attributed to the formation of the structural distortion.

16.
Inorg Chem ; 59(24): 18174-18180, 2020 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-33291874

RESUMEN

Molecular phase transition compounds have become a hot research area in recent years because of their potential as functional materials, such as ferroelectrics, ferroelastics, dielectric switches, etc. However, materials combining switchable dielectric properties and ferroelasticity are still rare. Here, we reported an organic-inorganic hybrid perovskite, [CPtmp][Cd(SCN)3] (1) ([CPtmp]+ is a cyclopentyltrimethylphosphonium cation), with a potential ferroelastic property. This material undergoes three structural phase transitions at 247/226, 335/312, and 349/341 K (upon heating/cooling). The successive phase transitions are mainly caused by the stepwise ordering of [CPtmp]+ cations and the concomitant deformation of [Cd(SCN)3]- anionic chains revealed by structural analyses, which triggers the double-step dielectric switching in 1 as well. These results would inspire further exploration on molecular dielectric switches with ferroelastic properties.

17.
Inorg Chem ; 59(24): 18396-18401, 2020 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-33270438

RESUMEN

The one-dimensional (1D) ABX3-type perovskite [(CH3)3PCH2F]CdCl2Br (1) has been obtained on the basis of the design of an organic-inorganic hybrid. Strikingly, it experiences sequential phase transitions at around 295 and 336 K, respectively. Given the noticeable steplike dielectric anomalies in the vicinity of 295 K, 1 is identified as a promising dielectric-switchable material. According to the single-crystal structure analysis, the order-to-disorder transformation of the [(CH3)3PCH2F]+ cation is the main reason for the phase transitions and the change of space group from the orthorhombic Pnma (No. 62) to the hexagonal P63/m (No. 176). This design of a perovskite structure will inspire more advances in the ever-growing field of switchable functional materials.

18.
Inorg Chem ; 59(7): 4720-4728, 2020 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-32163278

RESUMEN

Dual phase transition/switch materials are a critical cornerstone of information storage and sensing. However, they are difficult to design successfully, and compared with materials showing single-switchable phase transitions, the dual ones retain many challenges by far. Therefore, the significance of a general strategy is far greater than an accidental success. Here, an efficient strategy combining branchlike Et3R and trunklike benzylamine analogues successfully validates dual-switch implementation in the dielectric materials. This inevitable success is based on our treelike analogue mentioned above in which amines with multiple branches can achieve a temperature-induced phase change. Exactly, (BCDA)2ZnBr4 [BCDA = benzyl-(2-chloroethyl)dimethylammonium] proves the regularity and undergoes two reversible phase transitions at 295.4 and 340.8 K, respectively. Variable-temperature single-crystal X-ray diffraction revealed that the generation of double phase transitions is caused by progressive changes of treelike BCDA+ as the temperature rises. Because the permittivity ε' of (BCDA)2ZnBr4 abruptly changed near the phase-transition temperatures, such physical properties make it have latent applicability. In short, the success of our strategy will inspire researches to discover more interesting dual phase transition/switch materials.

19.
NMR Biomed ; 32(9): e4126, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31290588

RESUMEN

Diffusion magnetic resonance imaging has been demonstrated to be a simple, noninvasive and accurate method for the detection of renal microstructure and microcirculation, which are closely linked to renal function. Moreover, serum endothelin-1 (ET-1) was also reported as a good indicator of early renal injury. The aim of this study was to evaluate the feasibility and capability of diffusion MRI and ET-1 to detect acute kidney injury by an operation simulating high-pressure renal pelvic perfusion, which is commonly used during ureteroscopic lithotripsy. Histological findings were used as a reference. Fourteen New Zealand rabbits in an experimental group and 14 in a control group were used in this study. Diffusion tensor imaging and intravoxel incoherent motion diffusion-weighted imaging were acquired by a 3.0 T MRI scanner. Significant corticomedullary differences were found in the values of the apparent diffusion coefficient (ADC), pure tissue diffusion, volume fraction of pseudo-diffusion (fp) and fractional anisotropy (FA) (P < 0.05 for all) in both preoperation and postoperation experimental groups. Compared with the control group, the values of cortical fpmean , medullary ADCmean and FAmean decreased significantly (P < 0.05) after the operation in the experimental group. Also, the change rate of medullary ADCmean in the experimental group was more pronounced than that in the control group (P = 0.018). No significant change was found in serum ET-1 concentration after surgery in either the experimental (P = 0.80) or control (P = 0.17) groups. In the experimental group, histological changes were observed in the medulla, while no visible change was found in the cortex. This study demonstrated the feasibility of diffusion MRI to detect the changes of renal microstructure and microcirculation in acute kidney injury, with the potential to evaluate renal function. Moreover, the sensitivity of diffusion MRI to acute kidney injury appears to be superior to that of serum ET-1.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Riñón/diagnóstico por imagen , Enfermedad Aguda , Animales , Anisotropía , Riñón/patología , Perfusión , Conejos
20.
Chemistry ; 25(25): 6447-6454, 2019 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-30968482

RESUMEN

Organic-inorganic hybrid perovskite-type multiferroics have attracted considerable research interest owing to their fundamental scientific significance and promising technological applications in sensors and multiple-state memories. The recent achievements with divalent metal dicyanamide compounds revealed such malleable frameworks as a unique platform for developing novel functional materials. Herein, two 3D organic-inorganic hybrid perovskites [Et3 P(CH2 )2 F][Mn(dca)3 ] (1) and [Et3 P(CH2 )2 Cl][Mn(dca)3 ] (2) (dca=dicyanamide, N(CN)2 - ) are presented. Accompanying the sequential phase transitions, they display a broad range of intriguing physical properties, including above room temperature ferroelastic behavior, switchable dielectricity, and low-temperature antiferromagnetic ordering (Tc =2.4 K for both 1 and 2). It is also worth noting that the spontaneous strain value of 1 is far beyond that of 2 in the first ferroelastic phase, as a result of the precise halogen substitution. From the point view of molecular design, this work should inspire further exploration of multifunctional molecular materials with desirable properties.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA