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1.
Opt Express ; 32(11): 19057-19068, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38859049

RESUMO

A Fabry-Pérot interferometer (FPI) with an asymmetric tapered structure and air microbubble with an ultrathin wall is designed for high-sensitivity strain measurement. The sensor contains an air microbubble formed by two single-mode fibers (SMF) prepared by fusion splicer arc discharge, and a taper is applied to one side of the air microbubble with a wall thickness of 3.6 µm. In this unique asymmetric structure, the microbubble is more easily deformed under stress, and the strain sensitivity of the sensor is up to 15.89 pm/µÉ› as evidenced by experiments.The temperature sensitivity and cross-sensitivity of the sensor are 1.09 pm/°C and 0.069 µÉ›/°C in the temperature range of 25-200°C, respectively, thus reducing the measurement error arising from temperature variations. The sensor has notable virtues such as high strain sensitivity, low-temperature sensitivity, low-temperature cross-sensitivity, simple and safe process preparation, and low cost. Experiments confirm that the sensor has good stability and repeatability, and it has high commercial potential, especially strain measurements in complex environments.

2.
BMC Nephrol ; 24(1): 293, 2023 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-37794407

RESUMO

BACKGROUND: Parathyroid carcinoma and parathyromatosis are very rare diseases in patients on hemodialysis. Its pathogenesis, clinical features, preoperative diagnosis, and surgery are challenging. We describe a rare case of recurrent hyperparathyroidism due to synchronous parathyroid carcinoma and parathyromatosis. CASE PRESENTATION: A 46-year-old Chinese woman was diagnosed with end-stage renal disease and received regular hemodialysis. Four years later, she experienced discomfort due to itching and was diagnosed with drug-resistant secondary hyperparathyroidism. Parathyroidectomy was performed, and her parathyroid hormone (PTH) levels were reduced. The pathology also revealed that the four nodules were parathyroid nodular hyperplasia without evidence of malignancy. Five years after surgery, the right subcutaneous nodule and left inferior nodule were detected by multiple imaging modalities, and the nodules were accompanied by recurrence itching and elevation of PHT. A complete resection of two nodules was performed, and the patient was diagnosed with parathyroid carcinoma and parathyromatosis. At 8 months postsurgery, her PHT and serum calcium levels were stable, and there were no signs of recurrence. CONCLUSIONS: This is a rare case of synchronous parathyroid carcinoma and parathyromatosis in a patient with secondary hyperparathyroidism after parathyroidectomy. We suggest meticulous handling of parathyroid hyperplasia to avoid rupture and spillage during surgery, and precise pro-operation location by multiple imaging modalities is crucial for successful parathyroidectomy.


Assuntos
Hiperparatireoidismo Primário , Hiperparatireoidismo Secundário , Neoplasias das Paratireoides , Humanos , Feminino , Pessoa de Meia-Idade , Neoplasias das Paratireoides/complicações , Neoplasias das Paratireoides/diagnóstico por imagem , Neoplasias das Paratireoides/cirurgia , Hiperplasia/patologia , Glândulas Paratireoides/diagnóstico por imagem , Glândulas Paratireoides/cirurgia , Glândulas Paratireoides/patologia , Hiperparatireoidismo Primário/complicações , Hiperparatireoidismo Primário/cirurgia , Hiperparatireoidismo Secundário/complicações , Hiperparatireoidismo Secundário/diagnóstico por imagem , Paratireoidectomia/efeitos adversos , Diálise Renal/efeitos adversos , Prurido , Recidiva , Hormônio Paratireóideo
3.
Macromol Rapid Commun ; 43(5): e2100768, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34964192

RESUMO

Stimuli-responsive structurally dynamic polymers are capable of mimicking the biological systems to adapt themselves to the surrounding environmental changes and subsequently exhibiting a wide range of responses ranging from self-healing to complex shape-morphing. Dynamic self-healing polymers (SHPs), shape-memory polymers (SMPs), and liquid crystal elastomers (LCEs), which are three representative examples of stimuli-responsive structurally dynamic polymers, have been attracting broad and growing interest in recent years because of their potential applications in the fields of electronic skin, sensors, soft robots, artificial muscles, and so on. Recent advances and challenges in the developments toward dynamic SHPs, SMPs, and LCEs are reviewed, focusing on the chemistry strategies and the dynamic reaction mechanisms that enhance the performances of the materials including self-healing, reprocessing, and reprogramming. The different dynamic chemistries and their mechanisms on the enhanced functions of the materials are compared and discussed, where three summary tables are presented: A library of dynamic bonds and the resulting characteristics of the materials. Finally, a critical outline of the unresolved issues and future perspectives on the emerging developments is provided.


Assuntos
Cristais Líquidos , Materiais Inteligentes , Dispositivos Eletrônicos Vestíveis , Elastômeros/química , Cristais Líquidos/química , Polímeros/química
4.
Angew Chem Int Ed Engl ; 60(10): 5536-5543, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33217118

RESUMO

Shape-switching behavior, where a transient stimulus induces an indefinitely stable deformation that can be recovered on exposure to another transient stimulus, is critical to building smart structures from responsive polymers as continue power is not needed to maintain deformations. Herein, we 4D-print shape-switching liquid crystalline elastomers (LCEs) functionalized with supramolecular crosslinks, dynamic covalent crosslinks, and azobenzene. The salient property of shape-switching LCEs is that light induces long-lived, deformation that can be recovered on-demand by heating. UV-light isomerizes azobenzene from trans to cis, and temporarily breaks the supramolecular crosslinks, resulting in a programmed deformation. After UV, the shape-switching LCEs fix more than 90 % of the deformation over 3 days by the reformed supramolecular crosslinks. Using the shape-switching properties, we print Braille-like actuators that can be photoswitched to display different letters. This new class of photoswitchable actuators may impact applications such as deployable devices where continuous application of power is impractical.

5.
BMC Infect Dis ; 19(1): 1000, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31775654

RESUMO

BACKGROUND: The prevalence of HIV among men who have sex with men (MSM) has become a significant public health challenge. The aim was to comprehensively estimate the national prevalence of HIV among MSM and its time trends through a large-scale systematic analysis. METHODS: Systematic search of Cochrane Library, PubMed, EMBASE, CNKI, VIP, and Wanfang Data databases without language restriction for studies on the prevalence of HIV among MSM published before Dec.31, 2018. Studies were eligible for inclusion if they were published in the peer-reviewed literature and used validated assessment methods to assess the prevalence of HIV among MSM. Estimates were pooled using random-effects analysis. RESULTS: Data were extracted from 355 cross-sectional studies (571,328 individuals) covered 59 cities from 30 provinces and municipalities of China. The overall national prevalence of HIV among MSM from 2001 to 2018 was estimated to be 5.7% (95% CI: 5.4-6.1%), with high between-study heterogeneity (I2 = 98.0%, P <  0.001). Our study showed an increased tendency in the HIV prevalence as time progressed by meta-regression analysis (I2 = 95.9%, P <  0.0001). HIV prevalence was the highest in those aged 50 years and older with HIV prevalence of 19.3% (95%CI: 13.1-27.4%, N = 13). HIV was more prevalent in the illiterate population (16.8%), than in those who had received an education. Although the internet was a major venue for Chinese MSM seeking male sex partners (35.6, 95%CI: 32.3-39.9%, N = 101), seeking MSM in bathhouses/saunas had the highest associated prevalence of HIV (13.4, 95%CI: 10.3-17.1%, N = 22). The HIV prevalence among MSM varied by location: compared with other regions in China, HIV was highly prevalent among MSM in the southwest (10.7, 95%CI: 9.3-12.2%, N = 91). Compared to participants who sometimes or always used condoms, participants who had never used a condom in the past 6 months had a higher risk of HIV infection, with odds ratios of 0.1 (95%CI: 0.08-0.14). CONCLUSIONS: Our analysis provided reliable estimates of China's HIV burden among MSM, which appears to present an increasing national public health challenge. Effective government responses are needed to address this challenge and include the implementation of HIV prevention.


Assuntos
Infecções por HIV/epidemiologia , Saúde Pública/métodos , Minorias Sexuais e de Gênero , Adolescente , Adulto , Fatores Etários , China/epidemiologia , Cidades/epidemiologia , Preservativos , Estudos Transversais , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Humanos , Internet , Alfabetização , Masculino , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Parceiros Sexuais , Adulto Jovem
6.
BMC Public Health ; 19(1): 578, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31092218

RESUMO

BACKGROUND: In China, the most populous developing country in the world, dementia represents a serious challenge. We performed a large-scale systematic review and meta-regression analysis to elucidate the prevalence of dementia and its subtypes and to identify potential factors underlying the differences between articles. METHODS: A comprehensive literature search was conducted in the following databases to identify studies published up to December 2015: Cochrane Library, CBMDISK, Chongqing VIP, CNKI, PubMed and EMBASE. All statistical analyses (including subtype and meta-regression analyses) were performed with R version 3.3.3. RESULTS: In total, 51 surveys were selected. The pooled prevalence rates of dementia and its main subtypes, namely, Alzheimer's disease (AD) and vascular dementia (VAD), for the population aged 55 years and older were 4.03, 2.44 and 1.09%, respectively. The outcomes showed that the meta-regression analysis was affected by the publication year, sample size, region and diagnostic criteria. CONCLUSIONS: Our analysis provided reliable estimates of the prevalence of dementia/ AD/ VD over the past 30 years, which may be affected by education level, and diagnostic criteria. The prevalence of AD/VAD was higher in northern than in southern China, which warrants further study.


Assuntos
Demência/epidemiologia , Idoso , Doença de Alzheimer/epidemiologia , China/epidemiologia , Bases de Dados Factuais , Demência Vascular/epidemiologia , Humanos , Pessoa de Meia-Idade , Prevalência , Análise de Regressão
7.
Opt Express ; 26(7): 9039-9049, 2018 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-29715862

RESUMO

Symmetrical dual D-shape photonic crystal fibers (PCFs) for surface plasmon resonance (SPR) sensing are designed and analyzed by the finite element method (FEM). The performance of the sensor is remarkably enhanced by the directional power coupling between the two fibers. We study the influence of the structural parameters on the performance of the sensor as well as the relationship between the resonance wavelengths and analyze refractive indexes between 1.36 and 1.41. An average spectral sensitivity of 14660 nm/RIU can be achieved in this sensing range and the corresponding refractive index resolution is 6.82 × 10-6 RIU. The characteristics of a single D-shape PCF-SPR sensor with the same structural parameters are compared with those of the dual PCFs sensor and the latter has distinct advantages concerning the spectral sensitivity, resolution, amplitude sensitivity, and figure of merits (FOM).

8.
Opt Express ; 25(13): 14227-14237, 2017 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-28789008

RESUMO

A surface plasmon resonance (SPR) sensor with two open-ring channels based on a photonic crystal fiber (PCF) is described. The sensor is designed to detect low refractive indexes between 1.23 and 1.29 with the operation wavelength in mid-infrared region between 2550 nm and 2900 nm. The coupling characteristics and sensing properties are numerically analyzed by the finite element method. The average spectral sensitivity is 5500 nm/RIU and a maximum resolution of 7.69 × 10-6 RIU can be obtained. Our analysis shows that the PCF-SPR sensor is suitable for mid-infrared detection.

9.
Cardiology ; 138(1): 26-33, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28554182

RESUMO

OBJECTIVES: The relationship between a fragmented QRS (fQRS) and clinical outcomes in patients with hypertrophic cardiomyopathy (HCM) remains unclear. This study aimed to investigate the prognostic significance of fQRS in patients with HCM. METHODS: Between 2000 and 2012, 326 unrelated patients with HCM (72% male with a mean age of 52 years) were included and were divided into 2 groups: those with fQRS and those without fQRS. RESULTS: A total of 105/326(32.2%) patients with HCM presented with fQRS at enrollment. During a follow-up of 5.3 ± 2.4 years, 33 patients died, 30 of cardiovascular disease (CVD). Cox regression analysis revealed that fQRS predicted a higher risk of all-cause mortality (adjusted hazard ratio [HR] 2.24; 95% confidence interval [CI] 1.08-4.64; p = 0.030) and CVD mortality (adjusted HR 2.68; 95% CI 1.22-5.91; p = 0.014). Our study also showed that fQRS increased the risk of heart failure-related death (adjusted HR 3.75; 95% CI 1.24-11.30; p = 0.019). CONCLUSIONS: Our results indicate that fQRS is associated with adverse clinical outcomes in patients with HCM.


Assuntos
Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/mortalidade , Ecocardiografia , Insuficiência Cardíaca/complicações , Adulto , Idoso , Pequim , Causas de Morte , Morte Súbita Cardíaca/etiologia , Eletrocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais
10.
Angew Chem Int Ed Engl ; 56(22): 6126-6130, 2017 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-28370828

RESUMO

Photoresponsive actuators based on semicrystalline poly(ethylene-co-vinyl acetate) (EVA) loaded with small amounts of gold nanoparticles (AuNPs) are described. Upon absorption of light (532 nm), the heat released by the AuNPs raises the temperature in the irradiated region to Tlight to melt crystallites with lower melting temperatures (Tm Tlight . Once the light is turned off, the recrystallization of oriented chains in the actuation domains upon cooling gives rise to an expansion force. We show that the photoinduced contraction force, Tlight , and the speed for reaching Tlight can readily be adjusted, which makes EVA/AuNP a robust, fast optical actuation system tunable in both speed and magnitude. The material design can easily be extended to other temperature-memory semicrystalline polymers in combination with various light-absorbing and heat-generating additives.

11.
Adv Mater ; 36(7): e2307210, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37805917

RESUMO

The sophisticated and complex haptonastic movements in response to environmental-stimuli of living organisms have always fascinated scientists. However, how to fundamentally mimic the sophisticated hierarchical architectures of living organisms to provide the artificial counterparts with similar or even beyond-natural functions based on the underlying mechanism remains a major scientific challenge. Here,  liquid crystal elastomer (LCE) artificial tendrils showing evolutionary biomimetic locomotion are developed following the structure-function principle that is used in nature to grow climbing plants. These elaborately designed tendril-like LCE actuators possess an asymmetric core-sheath architecture which shows a higher-to-lower transition in the degree of LC orientation from the sheath-to-core layer across the semi-ellipse cross-section. Upon heating and cooling, the LCE artificial tendril can undergo reversible tendril-like shape-morphing behaviors, such as helical coiling/winding, and perversion. The fundamental mechanism of the helical shape-morphing of the artificial tendril is revealed by using theoretical models and finite element simulations. Besides, the incorporation of metal-ligand coordination into the LCE network provides the artificial tendril with reconfigurable shape-morphing performances such as helical transitions and rotational deformations. Finally, the abilities of helical and rotational deformations are integrated into a new reprogrammed flagellum-like architecture to perform evolutionary locomotion mimicking the haptonastic movements of the natural flagellum.


Assuntos
Biomimética , Cristais Líquidos , Locomoção , Evolução Biológica , Elastômeros
12.
J Mater Chem B ; 8(31): 6988-6998, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32626869

RESUMO

Approaches to control the microstructure of hydrogels enable the control of cell-material interactions and the design of stimuli-responsive materials. We report a versatile approach for the synthesis of anisotropic polyacrylamide hydrogels using lyotropic chromonic liquid crystal (LCLC) templating. The orientational order of LCLCs in a mold can be patterned by controlling surface anchoring conditions, which in turn patterns the polymer network. The resulting hydrogels have tunable pore size and mechanical anisotropy. For example, the elastic moduli measured parallel and perpendicular to the LCLC order are 124.9 ± 6.4 kPa and 17.4 ± 1.1 kPa for a single composition. The resulting anisotropic hydrogels also have 30% larger swelling normal to the LCLC orientation than along the LCLC orientation. By patterning the LCLC order, this anisotropic swelling can be used to create 3D hydrogel structures. These anisotropic gels can also be functionalized with extracellular matrix (ECM) proteins and used as compliant substrata for cell culture. As an illustrative example, we show that the patterned hydrogel microstructure can be used to direct the orientation of cultured human corneal fibroblasts. This strategy to make anisotropic hydrogels has potential for enabling patternable tissue scaffolds, soft robotics, or microfluidic devices.


Assuntos
Hidrogéis/química , Cristais Líquidos/química , Anisotropia , Linhagem Celular , Módulo de Elasticidade , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/metabolismo , Hidrogéis/farmacologia , Porosidade
13.
Biomaterials ; 232: 119719, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31901688

RESUMO

Tissue adhesives are commonly used in surgeries and regenerative engineering for the repair and regeneration of topical and internal wounds on tissues and organs such as skin, heart, blood vessels, and bone. However, achieving rapid crosslinking, strong wet adhesion and cohesion strengths, and minimal cytotoxicity remains a critical roadblock for clinical translation. Herein, in contrast to harsh and cytotoxic oxidants, magnesium oxide (MgO) particles were found to facilitate rapid crosslinking for injectable citrate-based mussel-inspired tissue bioadhesives synthesized by reacting citric acid, PEG-PPG-PEG diol and dopamine (iC-EPE). Our results confirmed the role of MgO particles as both crosslinkers and composite fillers to concurrently enhance bioadhesive cohesion and adhesion. iC-EPE crosslinked by MgO with/without sodium periodate (PI) exhibit enhanced mechanical strengths (1.0 Mpa < tensile strength ≤ 4.5 MPa) compared to that of iC-EPE crosslinked only by PI (~0.75 MPa), high adhesion strength (up to 125 kPa, 8 fold that of fibrin glue (~15 kPa)), tunable degradability (full degradation from <1 week to > 1 month), excellent in vitro and in vivo biocompatibility, encouraging anti-bacterial performance, and favorable wound closure efficacy. Thus, MgO crosslinked bioadhesives possess great potential for a wide range of applications in surgery and regenerative engineering.


Assuntos
Bivalves , Adesivos Teciduais , Adesivos , Animais , Citratos , Ácido Cítrico , Óxido de Magnésio
14.
J Mater Chem B ; 7(32): 4876-4926, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31411621

RESUMO

Significant advances have been made in the development of self-healing synthetic polymer materials in recent years. This review article discusses the recent progress in preparation, characterization and properties of different kinds of intrinsic self-healing elastomers based on reversible covalent bonds and dynamic supramolecular chemistry. Healing conditions, mechanical property recovery and healing efficiency are the main discussion topics. Potential applications, challenges and future prospects in self-healing elastomer fields are also discussed in the last part of this review.


Assuntos
Elastômeros/química , Fenômenos Mecânicos , Temperatura
15.
ACS Appl Mater Interfaces ; 11(47): 44774-44782, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31692319

RESUMO

Liquid crystal elastomers (LCEs), a class of soft materials capable of a large and reversible change in the shape under the trigger of external stimuli, can be fabricated into diverse architectures with complicated deformation modes through four-dimensional (4D) printing. However, the printable LCE ink is only in the form of monomeric precursors and the deformation mode is limited to contraction/extension deformation. Herein, we report a novel approach to break through these limitations. We achieved 4D printing of a single-component liquid crystal polymer ink in its isotropy state through direct ink writing (DIW) technology. The drawing force imposed by the movement of nozzle in the extruded printing process was able to align the mesogen units along the specific printing path. An orientation gradient perpendicular to the printing direction was obtained due to the existence of a temperature gradient between the two sides of printed samples and could be further fixed by post-photo-cross-linking treatment through the dimerizable groups in the LCE, realizing a new actuation mode in the field of extrusion-based printing of LCE actuators. The printed film was able to change reversibly from a strip to a tightly hollow cylinder and could reversibly lift up an object with roughly 600 times its own weight. The orientation gradient can be patterned through liquid-assistant printing or programmed structure design to integrate both bending and contraction actuation modes on the same printed sample, leading to complex deformation and two-dimensional (2D) planar porous structure to three-dimensional (3D) porous cylinder transition. This study opens up a new prospect to directly print a wide variety of LCE actuators with versatile actuation modes.

16.
ACS Appl Mater Interfaces ; 10(46): 40189-40197, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30372013

RESUMO

Although shape-memory polymers (SMPs) can alter their shapes upon stimulation of environmental signals, complex shape transformations are usually realized by using advanced processing technologies (four-dimensional printing) and complicated polymer structure design or localized activation. Herein, we demonstrate that stepwise controlled complex shape transformations can be obtained from a single flat piece of SMP upon uniform heating. The shape-memory blends prepared by solution casting of poly(ethylene oxide) and poly(acrylic acid) (PAA) exhibit excellent mechanical and room-temperature shape-memory behaviors, with fracture strain beyond 800% and both shape memory and shape recovery ratio higher than 90%. After plastic deformation by stretching under ambient conditions, the material is surface-patterned to induce the formation of an Fe3+-coordinated PAA network with gradually altered cross-linking density along the thickness direction at desired areas. Upon subsequent heating for shape recovery, strain release is restricted by the PAA network to different extents depending on the cross-linking density, which results in bending deformation toward the nonpatterned side and leads to three-dimensional shape transformation of the SMP. More interestingly, by sequentially dissociating the PAA network via UV or visible light-induced photoreduction of Fe3+ to Fe2+, residual strains can be removed in a spatially controlled manner. Using this approach, a series of origami shapes are obtained from a single SMP with a tailored two-dimensional initial shape. We also demonstrate that by incorporating polydopamine nanoparticles as photothermal fillers into the material, the whole shape transformation process can be carried out at room temperature by using near-infrared light.

17.
Adv Mater ; 30(14): e1706597, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29430745

RESUMO

A near-infrared-light (NIR)- and UV-light-responsive polymer nanocomposite is synthesized by doping polymer-grafted gold nanorods into azobenzene liquid-crystalline dynamic networks (AuNR-ALCNs). The effects of the two different photoresponsive mechanisms, i.e., the photochemical reaction of azobenzene and the photothermal effect from the surface plasmon resonance of the AuNRs, are investigated by monitoring both the NIR- and UV-light-induced contraction forces of the oriented AuNR-ALCNs. By taking advantage of the material's easy processability, bilayer-structured actuators can be fabricated to display photocontrollable bending/unbending directions, as well as localized actuations through programmed alignment of azobenzene mesogens in selected regions. Versatile and complex motions enabled by the enhanced photocontrol of actuation are demonstrated, including plastic "athletes" that can execute light-controlled push-ups or sit-ups, and a light-driven caterpillar-inspired walker that can crawl forward on a ratcheted substrate at a speed of about 13 mm min-1 . Moreover, the photomechanical effects arising from the two types of light-triggered molecular motion, i.e., the trans-cis photoisomerization and a liquid-crystalline-isotropic phase transition of the azobenzene mesogens, are added up to design a polymer "crane" that is capable of performing light-controlled, robot-like, concerted macroscopic motions including grasping, lifting up, lowering down, and releasing an object.

18.
Adv Sci (Weinh) ; 5(5): 1800101, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29876226

RESUMO

Combining self-healing functions with damage diagnosing, which can achieve timely healing autonomously, is expected to improve the reliability and reduce life cycle cost of materials. Here, a flexible conductive composite composed of a dynamically crosslinked polyurethane bearing Diels-Alder bonds (PUDA) and carbon nanotubes (CNTs), which possess both crack diagnosing and self-healing functions, is reported. The introduced dynamic Diels-Alder bonds endow the materials self-healing function and the powder-based preparation route based on the specially designed CNTs-coated PUDA micropowders leads to the formation of segregated CNTs network, which makes the composite possess excellent mechanical properties and high conductivity. Because of the sufficient electrothermal and photothermal effect of CNTs, the composites can be healed rapidly and repeatedly by electricity or near-infrared light based on the retro-Diels-Alder reaction. An obvious color difference in the infrared thermograph resulting from the resistance difference between damaged and undamaged area can be observed when applying the voltage, which can be used for crack diagnosing. Using the same electrical circuit, the crack in the PUDA/CNTs composite can be noninvasively detected first and then be autonomously healed. The composites also exhibit a strain-sensing function with good sensitivity and high reliability, thus will have potential applications in electronic strain sensors.

19.
Acta Biomater ; 72: 35-44, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29555464

RESUMO

Tissue adhesives play an important role in surgery to close wounds, seal tissues, and stop bleeding, but existing adhesives are costly, cytotoxic, or bond weakly to tissue. Inspired by the water-resistant adhesion of plant-derived tannins, we herein report a new family of bioadhesives derived from a facile, one-step Michael addition of tannic acid and gelatin under oxidizing conditions and crosslinked by silver nitrate. The oxidized polyphenol groups of tannic acid enable wet tissue adhesion through catecholamine-like chemistry, while both tannic acid and silver nanoparticles reduced from silver nitrate provide antimicrobial sources inherent within the polymeric network. These tannin-inspired gelatin bioadhesives are low-cost and readily scalable and eliminate the concerns of potential neurological effect brought by mussel-inspired strategy due to the inclusion of dopamine; variations in gelatin source (fish, bovine, or porcine) and tannic acid feeding ratios resulted in tunable gelation times (36 s-8 min), controllable degradation (up to 100% degradation within a month), considerable wet tissue adhesion strengths (up to 3.7 times to that of fibrin glue), excellent cytocompatibility, as well as antibacterial and antifungal properties. The innate properties of tannic acid as a natural phenolic crosslinker, molecular glue, and antimicrobial agent warrant a unique and significant approach to bioadhesive design. STATEMENT OF SIGNIFICANCE: This manuscript describes the development of a new family of tannin-inspired antimicrobial bioadhesives derived from a facile, one-step Michael addition of tannic acid and gelatin under oxidizing conditions and crosslinked by silver nitrate. Our strategy is new and can be easily extended to other polymer systems, low-cost and readily scalable, and eliminate the concerns of potential neurological effect brought by mussel-inspired strategy due to the inclusion of dopamine. The tannin-inspired gelatin bioadhesives hold great promise for a number of applications in wound closure, tissue sealant, hemostasis, antimicrobial and cell/drug delivery, and would be interested to the readers from biomaterials, tissue engineering, and drug delivery area.


Assuntos
Antibacterianos , Antifúngicos , Gelatina , Taninos , Adesivos Teciduais , Animais , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Bovinos , Peixes , Gelatina/química , Gelatina/farmacologia , Suínos , Taninos/química , Taninos/farmacologia , Adesivos Teciduais/síntese química , Adesivos Teciduais/química , Adesivos Teciduais/farmacologia
20.
Nucl Med Commun ; 39(9): 818-824, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29877993

RESUMO

OBJECTIVE: The aim was to perform exploratory research on the application of technetium phytate (Tc-Phy) portal perfusion index (PPI) imaging in predicting the complications of hepatitis B cirrhosis and their severity. PATIENTS AND METHODS: A total of 65 hepatitis B cirrhosis patients were stratified, respectively, into three groups from classes A to C according to Child-Pugh scores and five groups from stages 1 to 5 according to the five-stage prognostic system. PPIs were compared and analyzed, respectively, among the three and five groups. The correlations between PPIs and major biochemical indices of liver function were also analyzed. One-way analysis of variance was used to compare the PPIs among the various groups and a nonparametric Spearman test was used to analyze the correlations between PPIs and various biochemical indices. RESULTS: PPIs of the five groups decreased gradually from stage 1 to stage 5 (73.03±8.49, 52.96±16.22, 46.24±15.25, 29.99±17.36, and 11.50±6.37, respectively); with the exception of the difference between stages 2 and 3 (P=0.252), the differences between the remaining groups were statistically significant (P<0.05). The PPI showed positive correlations with serum total protein, serum albumin, and albumin/globulin results (r=0.292, 0.559, 0.520, respectively; P<0.05), and negative correlations with serum globulin (r=-0.366, P<0.05). CONCLUSION: Technetium phytate PPI could be a promising noninvasive and effective method for predicting the complications of hepatitis B cirrhosis and their severity; a lower PPI value indicates a higher severity of complications for hepatitis B cirrhosis patients. PPI can provide very meaningful reference data for clinical practice.


Assuntos
Vírus da Hepatite B/fisiologia , Cirrose Hepática/diagnóstico por imagem , Cirrose Hepática/virologia , Compostos de Organotecnécio , Imagem de Perfusão , Ácido Fítico , Veia Porta/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Cirrose Hepática/metabolismo , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Adulto Jovem
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