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1.
Psychiatry Res ; 289: 113045, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32388418

RESUMO

What are the factors that worsen (vs. protect) emotional well-being during a pandemic outbreak such as COVID-19? Through two large-scale nationwide surveys (N1 = 11,131; N2 = 3,000) conducted in China immediately before versus during the coronavirus outbreak, we found that the onset of the coronavirus epidemic led to a 74% drop in overall emotional well-being. Factors associated with the likelihood of contracting the disease (e.g., residing near the epicenter), extent of potential harm (e.g., being an elderly), and relational issues (e.g., those within a marriage) exacerbated the detrimental effect of the outbreak on emotional well-being. Further, individuals' perception of their knowledge about coronavirus infection was another factor. Regardless of the actual amount of knowledge they possessed, those perceiving themselves as more knowledgeable, were able to experience more happiness during the outbreak. Higher perceived knowledge was associated with a stronger sense of control, which mediated the differences in emotional well-being. These patterns persisted even after controlling for a host of demographic and economic variables. In conclusion, public policies and mental health interventions aimed at boosting/protecting psychological well-being during epidemics should take account of these factors.

2.
Cancer Sci ; 111(2): 580-591, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31804030

RESUMO

Patients with lower-risk myelodysplastic syndromes (LR-MDS) as defined by the International Prognostic Scoring System (IPSS) have more favorable prognosis in general, but significant inter-individual heterogeneity exists. In this study, we examined the molecular profile of 15 MDS-relevant genes in 159 patients with LR-MDS using next-generation sequencing. In univariate COX regression, shorter overall survival (OS) was associated with mutation status of ASXL1 (P = .001), RUNX1 (P = .031), EZH2 (P = .049), TP53 (P = .016), SRSF2 (P = .046), JAK2 (P = .040), and IDH2 (P = .035). We also found significantly shorter OS in patients with an adjusted TET2 variant allele frequency (VAF) ≥18% versus those with either an adjusted TET2 VAF <18% or without TET2 mutations (median: 20.4 vs 47.8 months; P = .020; HR = 2.183, 95%CI: 1.129-4.224). After adjustment for IPSS, shorter OS was associated with mutation status of ASXL1 (P < .001; HR = 4.306, 95% CI: 2.144-8.650), TP53 (P = .004; HR = 4.863, 95% CI: 1.662-14.230) and JAK2 (P = .002; HR = 5.466, 95%CI: 1.848-16.169), as well as adjusted TET2 VAF ≥18% (P = .008; HR = 2.492, 95% CI: 1.273-4.876). Also, OS was increasingly shorter as the number of mutational factors increased (P < .001). A novel prognostic scoring system incorporating the presence/absence of the four independent mutational factors into the IPSS further stratified LR-MDS patients into three prognostically different groups (P < .001). The newly developed scoring system redefined 10.1% (16/159) of patients as a higher-risk group, who could not be predicted by the currently prognostic models. In conclusion, integration of the IPSS with mutation status/burden of certain MDS-relevant genes may improve the prognostication of patients with LR-MDS and could help identify those with worse-than-expected prognosis for more aggressive treatment.


Assuntos
Redes Reguladoras de Genes , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Mutação , Síndromes Mielodisplásicas/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Frequência do Gene , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Análise de Sequência de DNA/métodos , Análise de Sobrevida , Adulto Jovem
3.
Angew Chem Int Ed Engl ; 59(11): 4314-4319, 2020 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-31876353

RESUMO

Non-Newtonian fluids are ubiquitous in daily life and industrial applications. Herein, we report an intelligent fluidic system integrating two distinct non-Newtonian rheological properties mediated by an autocatalytic enzyme reaction. Associative polyelectrolytes bearing a small amount of ionic and alkyl groups are engineered: by carefully balancing the charge density and the hydrophobic effect, the polymer solutions demonstrate a unique shear thickening property at low pH while shear thinning at high pH. The urea-urease clock reaction is utilized to program a feedback-induced pH change, leading to a strong upturn of the nonlinear viscoelastic properties. As long as the chemical fuel is supplied, two distinct non-Newtonian states can be achieved with a tunable lifetime span. As a proof of concept, we demonstrate how the physical energy-driven nonequilibrium properties can be manipulated by a chemical-fueled process.

4.
Sci Total Environ ; 688: 880-889, 2019 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-31255825

RESUMO

Membrane distillation (MD) has great potential in the treatment of high-salinity and low-biodegradability wastewater, but membrane fouling restricts its real applications. In this work, MD was applied to treat anaerobic digestion effluent, and the feed pH was adjusted to investigate the membrane organic fouling and inorganic scaling. The results show that the fouling of MD membranes during the treatment of anaerobic digestion effluent was substantially alleviated at a low feed pH (pH=5). Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) were used to characterize the fouled membranes. The MD membrane scaling was primarily attributed to the deposition of calcium-, magnesium-, phosphate-, and silicon-related inorganic compounds during the treatment of cow dung anaerobic digestion effluent. Feed acidification significantly decreased inorganic scaling as well as fouling by organic matter, and organic fouling dominated the fouling process in the low-pH environment. By comparing the components in acid and alkaline cleaning solutions, it was found that the deposition of organics on the membranes via adsorption to inorganic scaling was the primary cause of more severe organic fouling with increasing feed pH. Hence, restricting inorganic scaling could be an effective way to control MD membrane fouling by organics during treatment of anaerobic digestion effluent.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Incrustação Biológica , Destilação , Membranas Artificiais , Águas Residuárias/química
5.
Blood Cells Mol Dis ; 75: 13-19, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30530101

RESUMO

We retrospectively analyzed 101 primary MDS patients with complex karyotype during January 2010 and April 2017.The median overall survival (OS) time was 13 (95% CI 9.98-16.02) months, and there was no significant difference in OS for different treatment. Chromosome 5/7 involvement was common (78.22%, 79/101) and associated with shorter OS (12 months vs. 28 months, P < 0.01) Monosomal karyotype (MK) is overlapped with CK in 79 patients, but was not statistically associated with shorter OS. While in 59 cases with genes sequenced, 57 (96.61%) patients were found to have at least one mutation of known significance, and TP53 was the most frequent (74.58%, 44/59), the median OS of patients with TP53 mutation was shorter than those without (10 vs. 27 months, P < 0.01). Multivariate analysis demonstrated that only TP53 mutation was the strongest independent prognostic factor for OS. Moreover, high variant allele frequency (VAF) of TP53 mutation (median VAF was 70.00%) was seen and associated with adverse survival (9 months vs. 13 months, p = 0.04). In conclusion, MDS patients with CK implied an unfavorable outcome regardless of any treatment, TP53 mutation occurs at a high frequency and has a higher VAF, both were associated with worse survival.


Assuntos
Cariótipo , Síndromes Mielodisplásicas/genética , China , Cromossomos Humanos Par 5 , Cromossomos Humanos Par 7 , Frequência do Gene , Humanos , Mutação , Síndromes Mielodisplásicas/mortalidade , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida , Proteína Supressora de Tumor p53/genética
6.
Leuk Lymphoma ; 60(5): 1136-1145, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30301399

RESUMO

It is controversial whether acute myeloid leukemia (AML) patients with 20-29% bone marrow (BM) blasts should be considered AML or myelodysplastic syndromes (MDS). We retrospectively studied 382 patients, including 108 AML with 20-29% BM blasts (AML20-29), 210 AML with ≥30% BM blasts (AML ≥ 30), and 64 MDS with 10-19% BM blasts (MDS-EB2). We found that AML20-29 were more similar to MDS-EB2 in terms of advanced age, less blood count, the increased presence of poor-risk cytogenetics. The frequency of mutated genes in AML20-29 had both the characters of AML and MDS. Median overall survival of AML20-29 and MDS-EB2 were similar and shorter than those of AML ≥ 30 (p = .045). Multivariate analysis showed inferior survival with increased age, low platelet count and FLT3 mutations. Our findings suggest that AML20-29 have clinical features more similar to MDS than AML.

7.
Macromol Rapid Commun ; 40(4): e1800691, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30565769

RESUMO

Polyion complex (PIC) hydrogels formed by charge attraction of opposite charged polymers have received unique research interest. Their conventional preparation method, with a large amount of residual salt after polymerization, requires a long-term dialysis treatment to remove the salt and toughen the gel. Here, a promising strategy for the one-step preparation of tough PIC hydrogels without dialysis after polymerization is provided. Bicarbonate and proton ions are selected as the counter ions of the cationic monomer and anionic polymers, respectively. By a CO2 -generating reaction between the counter ions, the residual salt is removed before polymerization, and thus, a PIC hydrogel with tough mechanical performance can be obtained instantly without dialysis. Due to the absence of dialysis, the tough hydrogel can be formed with a wide range of ratios for the oppositely charged polymer with distinct swelling behaviors from non-swelling to super-swelling. This tunable swelling behavior shows the possibility for shape-morphing systems from this one-step method.


Assuntos
Hidrogéis/síntese química , Polímeros/síntese química , Dióxido de Carbono/química , Hidrogéis/química , Íons/síntese química , Íons/química , Estrutura Molecular , Polímeros/química
8.
J Mater Chem B ; 7(1): 30-42, 2019 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-32254948

RESUMO

Metal coordination hydrogels have drawn intensive attention in controlled drug release due to their facile incorporation of stimuli and dynamic self-healing properties. However, many metal coordination hydrogels which are responsive to mild physiologically relevant stimuli are restricted by their poor stability in non-triggering environments. Here, we reported a new strategy for enhancing the neutral stability of a pH-responsive self-healing hydrogel based on multivalent metal coordination without loss of its responsiveness. The hydrogel was formed by multivalent coordination of Ni2+ with polyhistidine (PHis) and multiple iminodiacetic acid (IDA) ligands which were modified on the terminal groups of polyethylene glycol (PEG) and the side groups of oligochitosan (OChi), respectively. By incorporating multivalent coordination, the hydrogel maintains its self-healing character and weak acid responsiveness; it can also be used as an injectable hydrogel by injecting it into a neutral environment. Through varying the PHis : IDA ratio, the mechanical strength and dynamic relaxation of the hydrogel can be regulated conveniently. More importantly, the hydrogels with multivalent coordination can remain stable and integral in neutral buffer (pH 7.4); meanwhile, they dissolve quickly in a weak acid environment (pH 5.5), which is similar to some tissue disease conditions. In contrast, the control hydrogel without multivalent coordination disintegrated within 4 hours in the neutral non-triggering buffer. Because the hydrogel consists of large amounts of coordinative Ni2+ ions, it naturally possesses relatively high affinity to molecules containing polyhistidine motifs. Thus, pH-tuned controlled release of a model molecule, rhodamine-modified polyhistidine, was accomplished, with limited neutral leakage and quick release in weak acid. These results indicate potential applications for this multivalent coordination hydrogel in the controlled release field.


Assuntos
Quitina/análogos & derivados , Preparações de Ação Retardada , Hidrogéis , Polietilenoglicóis/química , Proteínas/química , Quitina/química , Hidrogéis/síntese química , Hidrogéis/química , Concentração de Íons de Hidrogênio , Iminoácidos/química , Níquel/química
9.
Am J Physiol Lung Cell Mol Physiol ; 315(6): L965-L976, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30211651

RESUMO

Platelet-derived growth factor (PDGF) can induce hyperproliferation of pulmonary artery smooth muscle cells (PASMCs), which is a key causative factor to the occurrence and progression of pulmonary arterial hypertension (PAH). We previously identified that miR-1181 is significantly downregulated by PDGFBB in human PASMCs. In this work, we further explore the function of miR-1181 and underlying regulatory mechanisms in PDGF-induced PASMCs. First, the expression pattern of miR-1181 was characterized under PDGFBB treatment, and PDGF receptor/PKCß signaling was found to repress miR-1181 expression. Then, gain- and loss-of-function experiments were respectively conducted and revealed the prominent role of miR-1181 in inhibiting PASMC proliferation and migration. Flow cytometry analysis suggested that miR-1181 regulated the PASMC proliferation through influencing the cell cycle transition from G0/G1 to S phase. Moreover, we exhibited that miR-1181 targeting STAT3 formed a regulatory axis to modulate PASMC proliferation. Finally, serum miR-1181 expression was also observed to be reduced in adult and newborn patients with PAH. Overall, this study provides novel findings that the miR-1181/STAT3 axis mediated PDGFBB-induced dysfunction in human PASMCs, implying a potential use of miR-1181 as a therapeutic and diagnostic candidate for the vascular remodeling diseases.


Assuntos
Becaplermina/farmacologia , Proliferação de Células/efeitos dos fármacos , MicroRNAs/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Artéria Pulmonar/efeitos dos fármacos , Fator de Transcrição STAT3/metabolismo , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Células HEK293 , Humanos , Hipertensão Pulmonar/tratamento farmacológico , Hipertensão Pulmonar/metabolismo , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Artéria Pulmonar/metabolismo , Receptores do Fator de Crescimento Derivado de Plaquetas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Remodelação Vascular/efeitos dos fármacos
10.
Soft Matter ; 14(36): 7420-7428, 2018 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-30187054

RESUMO

As one of the most promising biomaterials, injectable self-healing hydrogels have found broad applications in a number of fields such as local drug delivery. However, controlled release of drugs in hydrogels is still difficult to realize up to now. Here, we report a novel photo-degradable injectable self-healing hydrogel based on the hydrophobic interaction of a biocompatible four-arms star polymer, poly(ethylene glycol)-b-poly(γ-o-nitrobenzyl-l-glutamate). The hydrophobic interaction between poly(γ-o-nitrobenzyl-l-glutamate) not only connects poly(ethylene glycol)-b-poly(γ-o-nitrobenzyl-l-glutamate) together with a crosslink but also provides a hydrophobic domain to encapsulate hydrophobic pharmaceuticals such as doxorubicin (DOX). Due to the dynamic character of the hydrophobic interaction, the hydrogel exhibits excellent injectable and self-healing ability. In particular, the photolabile o-nitribenzyl ester group is cleaved under UV irradiation. As a result, the hydrophobic domain transforms into the hydrophilic one and the embedded DOX is released effectively. An increasing release ratio of DOX dramatically enhances the apoptosis ratio of HeLa cells. We expect these attractive properties may be beneficial to practical applications of the hydrogel as an effective local drug delivery means in a truly physiological environment.


Assuntos
Portadores de Fármacos/química , Hidrogéis/química , Peptídeos/química , Fotólise , Polietilenoglicóis/química , Apoptose/efeitos dos fármacos , Doxorrubicina/química , Doxorrubicina/farmacologia , Células HeLa , Humanos , Injeções , Micelas
11.
Macromol Rapid Commun ; 39(11): e1800109, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29722085

RESUMO

Utilizing the abnormal physiological conditions of disease tissues can result in a site-specific functionality with high control and efficiency of stimuli-responsive hydrogels. Here, a physiologically relevant pH-responsive and self-healing hydrogel is reported based on coordination between Ni2+ and four-arm poly(ethylene glycol)-b-polyhistidine (4PEG-PHis) that is synthesized by a novel and facile PHis preparation method using amino-terminalized four-arm PEG as the macroinitiator. Reversible PHisNi coordination bonds endow the hydrogel with multistimuli-triggered sol-gel transition (physiologically relevant pH, EDTA) and self-healing properties. It is also demonstrated that 4PEG-PHis could be used as an injectable hydrogel in phosphate buffer (pH 7.4), and excellent stability in neutral buffer via multivalent coordination is shown, thus indicating its potential applications in controlled drug release systems.


Assuntos
Histidina/química , Hidrogéis/química , Metais/química , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Ácido Edético/química , Hidrogéis/síntese química , Concentração de Íons de Hidrogênio , Índigo Carmim/química , Polietilenoglicóis/química
12.
Molecules ; 23(3)2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29494526

RESUMO

Oxidized sodium alginate is a handily modifiable polysaccharide owing to the pendant aldehyde groups which can form dynamic covalent bonds with amines, acylhydrazines, etc., providing oxidized sodium alginate-based hydrogels with stimuli-responsive properties. However, due to the stiffness and, in particular, the hydrophobicity of sodium alginate dialdehyde at low pH, the mechanical performance and pH stimuli responsiveness of oxidized sodium alginate-based hydrogels are still strictly limited. Herein, we report a new strategy to build an injectable, dual responsive, and self-healing hydrogel based on oxidized sodium alginate and hydrazide-modified poly(ethyleneglycol) (PEG). The hydrazide-modified PEG, referred to as PEG-DTP, acts as a macromolecule crosslinker. We found that the presence of PEG-DTP reduces the hydrophobicity of oxidized sodium alginate at low pH so effectively that even a pH-induced reversible sol-gel transitions can be realized. Meanwhile, the disulfide bonds in PEG-DTP endows the hydrogel with the other reversible sol-gel transitions by redox stimuli. In particular, due to the softness of PEG-DTP chains, mechanical performance was also enhanced significantly. Our results indicate we can easily integrate multi-stimuli responsiveness, injectability, and self-healing behavior together into an oxidized sodium alginate-based hydrogel merely by mixing an oxidized sodium alginate solution with PEG-DTP solution in certain proportions.


Assuntos
Alginatos/química , Hidrazinas/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Polietilenoglicóis/química , Linhagem Celular Tumoral , Sobrevivência Celular , Portadores de Fármacos , Liberação Controlada de Fármacos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Cinética , Fenômenos Mecânicos , Oxirredução
13.
J Cancer Res Clin Oncol ; 144(6): 1037-1047, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29549529

RESUMO

PURPOSE: The myelodysplastic syndromes (MDS) are a group of hematologic disorders characterized by the presence of somatically mutated hematopoietic stem cells (HSCs) that increase the risk of progression to secondary acute myeloid leukemia (sAML). Mutations in isocitrate dehydrogenase (IDHmut) are thought to correlate with the increased production of the oncogenic protein 2-hydroxyglutarate (2-HG) in AML. The aim of this study was to examine whether serum 2-HG has utility as a prognostic biomarker, and whether elevated 2-HG levels are predictive of IDH mutations in patients with MDS. METHODS: Genetic profiling was utilized to determine the genetic composition of a large cohort of MDS patients, including the presence or absence of IDH1 or IDH2 mutations (n = 281). Serum 2-HG levels were detected by liquid chromatography-tandem mass spectrometry. RESULTS: In the current study of MDS patients, elevated serum 2-HG levels were predictive of inferior overall- and leukemia-free survival irrespective of IPSS risk grouping. Higher serum 2-HG levels predicted the presence of IDH mutations. IDH2mut patients had a higher risk of leukemic transformation. The co-occurrence of DNMT3A or SRSF2 mutations was found to be increased in IDH2mut patients. IDH2 mutations were associated with significantly worse OS and LFS amongst patients with low-risk MDS by IPSS grouping. CONCLUSIONS: The noted predictive value of serum 2-HG levels and IDH2 mutations on OS and LFS support the use of biomarkers and/or underlying cytogenetics in novel prognostic scoring systems for MDS.


Assuntos
Glutaratos/sangue , Isocitrato Desidrogenase/genética , Leucemia Mieloide Aguda/enzimologia , Leucemia Mieloide Aguda/patologia , Mutação , Síndromes Mielodisplásicas/enzimologia , Síndromes Mielodisplásicas/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Estudos de Coortes , Feminino , Humanos , Leucemia Mieloide Aguda/sangue , Leucemia Mieloide Aguda/genética , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/sangue , Síndromes Mielodisplásicas/genética , Prognóstico , Adulto Jovem
14.
Polymers (Basel) ; 10(9)2018 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-30960921

RESUMO

Smart materials responsible to external stimuli such as temperature, pH, solvents, light, redox agents, and mechanical or electric/magnetic field, have drawn considerable attention recently. Herein, we described a novel rhodamine (Rh) mechanophore-based mechanoresponsive micellar hydrogel with excellent mechanochromic and mechanofluorescent properties. We found with astonishment that, due to the favorable activation of rhodamine spirolactam in the presence of water, together with the stress concentration effect, the mechanoresponsive sensitivity of this hydrogel was enhanced significantly. As a result, the stress needed to trigger the mechanochromic property of Rh in the hydrogel was much lower than in its native polymer matrix reported before. The hydrogel based on Rh, therefore, exhibited excellent mechanochromic property even at lower stress. Moreover, due to the reversibility of color on/off, the hydrogel based on Rh could be used as a reusable and erasable material for color printing/writing. Of peculiar importance is that the hydrogel could emit highly bright fluorescence under sufficient stress or strain. This suggested that the stress/strain of hydrogel could be detected quantificationally and effectively by the fluorescence data. We also found that the hydrogel could respond to acid/alkali and exhibited outstanding properties of acidichromism and acidifluorochromism. Up to now, hydrogels with such excellent mechanochromic and mechanofluorescent properties have rarely been reported. Our efforts may be essentially beneficial to the design of the mechanochromic and mechanofluorescent hydrogels with enhanced mechanoresponsive sensitivity, fostering their potential applications in a number of fields such as damage or stress/strain detection.

15.
Water Res ; 122: 398-406, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28622632

RESUMO

The pH value is a key parameter and affects sludge dewatering. Comprehensive understanding of the effects and mechanism of pH is important for sludge treatment process and sludge dewatering. The goal of this study was to evaluate the proposed mechanism of acid conditioning on sludge dewatering based on rheological analysis. At lower sludge pH, changes in floc structure, surface properties, and flocculation improved the performance of dewatering. Additionally, lower sludge pH caused the hydrolysis of EPS and intracellular materials, which released greater amounts of bound water. These changes resulted in altered rheological properties, weakening network strength and shrinking the linear viscoelastic regime, making the sludge system sensitive to shear. Thus, both the sludge dewatering rate and moisture reduction efficiency were improved by lowering the pH. These factors demonstrate that rheological analysis can understand the mechanism of acid conditioning on activated sludge dewatering better.


Assuntos
Reologia , Esgotos , Ácidos , Floculação , Água
16.
Soft Matter ; 13(11): 2135-2140, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-28220175

RESUMO

A new class of smart structural hydrogels is prepared by introducing dual cross-linkers into a single-network system. The present hydrogel, on the one hand, exhibits excellent mechanical properties; on the other hand, it exhibits thermally induced plasticity and a shape memory effect without any overlap.

17.
Nanotechnology ; 28(4): 045202, 2017 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-27977413

RESUMO

Ultraviolet photodetectors (UVPDs) were fabricated via the in situ growth of orthorhombic MoO3 nanobelts among interdigital electrodes. Two types of nanojunction, touching and interpenetration, were formed between neighboring nanobelts at different growth conditions. The photoresponse mechanism of the UVPDs greatly depends on the type of nanojunction. Nanojunctions formed with touching nanobelts possess switching characteristics due to the barrier height variation along with the UV illumination. The UVPD with the touching structure exhibits low noise, high UV sensitivity and fast speed, having a dark current of 1.4 nA, an on/off ratio of over 100 and a response time of below 1 s, at an applied voltage of 10 V. The enhanced performance can be attributed to the switching characteristics of the touching nanojunction.

18.
Water Res ; 106: 116-125, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27697681

RESUMO

High-rate anaerobic granular sludge reactors have been developed and are widely used for wastewater treatment. An accurate estimate of sludge rheological properties is required for the design and efficient operation of the digestion process. The present work determined the rheological behavior of anaerobic granular sludge obtained from a full-scale bioreactor at different solid concentrations, operation temperatures and particle sizes, and highlighted common features in flow and dynamic measurements. The granular sludge showed a shear-thinning behavior with a yield stress under flow measurements and a viscoelastic property in dynamic measurements. The structure of granules was nearly temperature-independent in the range of operational temperature (20-70 °C), but the total solid concentration and particle size had significant effects on not only the rheological properties, but also the operation of the bioreactors. In addition, anaerobic granular sludge could cross over from the strong-link regime to the weak-link regime as the solid concentration increased. Furthermore, we adopted a Wagner-type constitutive model to describe the time-dependent and non-linear viscoelastic behaviors of anaerobic granular sludge, and then evaluated its validity and limitation.


Assuntos
Esgotos/química , Eliminação de Resíduos Líquidos , Bactérias Anaeróbias , Reatores Biológicos , Reologia , Temperatura
19.
Macromol Rapid Commun ; 37(21): 1723-1728, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27633950

RESUMO

Injectable hydrogels have been commonly used as drug-delivery vehicles and tried in tissue engineering. Injectable self-healing hydrogels have great advantage over traditional injectable hydrogels because they can be injected as a liquid and then rapidly form bulk gels in situ at the target site under physiological conditions. This study develops an injectable thermosensitive self-healing hydrogel based on chain-extended F127 (PEO90 -PPO65 -PEO90 ) multi-block copolymer (m-F127). The rapid sol-gel transition ability under body temperature allows it to be used as injectable hydrogel and the self-healing property allows it to withstand repeated deformation and quickly recover its mechanical properties and structure through the dynamic covalent bonds. It is hoped that the novel strategy and the fascinating properties of the hydrogel as presented here will provide new opportunities with regard to the design and practical application of injectable self-healing hydrogels.


Assuntos
Hidrogel de Polietilenoglicol-Dimetacrilato/química , Hidrogel de Polietilenoglicol-Dimetacrilato/síntese química , Polietilenoglicóis/química , Propilenoglicóis/química , Concentração de Íons de Hidrogênio , Injeções , Estrutura Molecular
20.
J Am Chem Soc ; 138(37): 12017-20, 2016 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-27603100

RESUMO

Reproducible synthesis of the elusive merlinoite (mer) topology of zinc imidazolate (mer-Zn(Im)2, or ZIF-10) has been achieved by employing a simple macrocyclic solute-MeMeCH2-as a kinetic template. The corresponding phase-pure material, mer-MeMeCH2@Zn16(Im)32, is confirmed to be porous and exhibits one of the highest experimental surface areas (1893 m(2)/g, BET) yet reported for any ZIF. The X-ray single crystal structure of mer-MeMeCH2@Zn16(Im)32·xsolvent reveals the role of the macrocyle as an 8-fold hydrogen bond acceptor in templating the requisite double-eight rings (d8r) of the mer framework.

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