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1.
Clin Lab ; 70(5)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38747904

RESUMO

BACKGROUND: Hepatitis B caused by hepatitis B virus (HBV) infection is a serious global public health issue. Currently, serological indicators serve as important markers for the diagnosis of hepatitis B. It has been found that HBV core-related antigen (HBcrAg) correlates well with intrahepatic cccDNA, intrahepatic HBV DNA, serum HBV DNA, and hepatitis B e antigen (HBeAg). To provide a more reliable basis for the diagnosis and treatment of hepatitis B, we explored the correlation between HBcrAg and conventional serologic testing indicators and disease staging. METHODS: Five hundred forty-two patient serum samples were collected at the First Affiliated Hospital of Soochow University from November 2021 to March 2022. The serum HBcrAg was measured by the magnetic particle chemiluminescence method in addition with other serum indicators. RESULTS: HBcrAg statistically correlated with HBV DNA level (r = 0.655, p < 0.001) and HBeAg level (r = 0.945, p < 0.001. The mean HBcrAg levels in the immune-tolerant and immune-clearance phases were significantly higher than those in the immunologic-control phase and the reactivation phase. This study demonstrated that serum HBcrAg positively correlated with serum HBV DNA and HBeAg. Even in cases where HBV DNA and HBeAg are negative, there is still a higher positivity rate of HBcrAg in hepatitis B patients. CONCLUSIONS: HBcrAg is a reliable serum marker to avoid underdiagnosis of occult HBV infection.


Assuntos
Biomarcadores , DNA Viral , Antígenos do Núcleo do Vírus da Hepatite B , Antígenos E da Hepatite B , Vírus da Hepatite B , Hepatite B , Humanos , Antígenos do Núcleo do Vírus da Hepatite B/sangue , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Masculino , Feminino , Hepatite B/diagnóstico , Hepatite B/imunologia , Hepatite B/sangue , Hepatite B/virologia , Antígenos E da Hepatite B/sangue , Antígenos E da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Vírus da Hepatite B/genética , Adulto , Biomarcadores/sangue , Pessoa de Meia-Idade , DNA Viral/sangue , Adulto Jovem , Idoso , Adolescente
2.
Adv Sci (Weinh) ; 10(32): e2305194, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37752831

RESUMO

Single-atomic transition metal-nitrogen-carbon (M-N-C) structures are promising alternatives toward noble-metal-based catalysts for oxygen reduction reaction (ORR) catalysis involved in sustainable energy devices. The symmetrical electronic density distribution of the M─N4 moieties, however, leads to unfavorable intermediate adsorption and sluggish kinetics. Herein, a Fe-N-C catalyst with electronic asymmetry induced by one nearest carbon vacancy adjacent to Fe─N4 is conceptually produced, which induces an optimized d-band center, lowered free energy barrier, and thus superior ORR activity with a half-wave potential (E1/2 ) of 0.934 V in a challenging acidic solution and 0.901 V in an alkaline solution. When assembled as the cathode of a Zinc-air battery (ZAB), a peak power density of 218 mW cm-2 and long-term durability up to 200 h are recorded, 1.5 times higher than the noble metal-based Pt/C+RuO2 catalyst. This work provides a new strategy on developing efficient M-N-C catalysts and offers an opportunity for the real-world application of fuel cells and metal-air batteries.

3.
Sci Rep ; 13(1): 6409, 2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37076518

RESUMO

The most critical parameter for determining equivalent values for the Mohr-Coulomb friction angle and cohesion from the nonlinear Hoek-Brown criterion is the upper limit of confining stress. For rock slopes, this value is the maximum value of the minimum principal stress ([Formula: see text]) on the potential failure surface. The existing problems in the existing research are analyzed and summarized. Using the finite element method (FEM), the location of potential failure surfaces for a wide range of slope geometries and rock mass properties are calculated using the strength reduction method, and a corresponding finite element elastic stress analysis was carried in order to determine [Formula: see text] of the failure surface. Through a systematic analysis of 425 different slopes, it is found that slope angle (ß) and geological strength index (GSI) have the most significant influence on [Formula: see text] while the influence of intact rock strength and the material constant [Formula: see text] are relatively small. According to the variation of [Formula: see text] with different factors, two new formulas for estimating [Formula: see text] are proposed. Finally, the proposed two equations were applied to 31 real case studies to illustrate the applicability and validity.

4.
Cell Signal ; 107: 110685, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37084840

RESUMO

OBJECTIVE: Glutamate ionotropic receptor N-methyl-d-aspartate (NMDA) type subunit 2D (GRIN2D) is a member of the GRIN gene family and contributes to the development and function of the brain. GRIN2D was found to be upregulated in several types of cancers; however, its mechanism in lung adenocarcinoma (LUAD) remains unclear. METHODS: We determined the role of GRIN2D in LUAD. In addition, we investigated the potential mechanism of GRIN2D in LUAD using bioinformatics analysis and confirmed this mechanism using biological approaches. RESULTS: GRIN2D was found to be upregulated in LUAD tissues and cells. GRIN2D knockdown reduced the proliferation and accelerated the apoptosis of LUAD cells. GRIN2D also activated glycolysis, gluconeogenesis, and the E2F signalling pathway in LUAD. GRIN2D knockdown significantly inhibited glucose uptake, lactate production, the ATP/ADP ratio, ECAR, and OCR in LUAD cells. E2F1 overexpression eliminated the inhibitory effect of GRIN2D knockdown in LUAD cells. CONCLUSIONS: GRIN2D knockdown suppresses cell growth, migration, glycolysis, and gluconeogenesis of LUAD by inhibiting the E2F signalling pathway.


Assuntos
Adenocarcinoma de Pulmão , Adenocarcinoma , Neoplasias Pulmonares , Humanos , Adenocarcinoma de Pulmão/genética , Transdução de Sinais , Proliferação de Células/genética , Ácido Láctico , Neoplasias Pulmonares/genética , Regulação Neoplásica da Expressão Gênica , Receptores de N-Metil-D-Aspartato
5.
Adv Sci (Weinh) ; 9(35): e2204297, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36266983

RESUMO

Exploring low-cost and high-efficient electrocatalyst is an exigent task in developing novel sustainable energy conversion systems, such as fuel cells and electrocatalytic fuel generations. 2D materials, specifically 2D superlattice materials focused here, featured highly accessible active areas, high density of active sites, and high compatibility with property-complementary materials to form heterostructures with desired synergetic effects, have demonstrated to be promising electrocatalysts for boosting the performance of sustainable energy conversion and storage devices. Nevertheless, the reaction kinetics, and in particular, the functional mechanisms of the 2D superlattice-based catalysts yet remain ambiguous. In this review, based on the recent progress of 2D superlattice materials in electrocatalysis applications, the rational design and fabrication of 2D superlattices are first summarized and the application of 2D superlattices in electrocatalysis is then specifically discussed. Finally, perspectives on the current challenges and the strategies for the future design of 2D superlattice materials are outlined. This review attempts to establish an intrinsic correlation between the 2D superlattice heterostructures and the catalytic properties, so as to provide some insights into developing high-performance electrocatalysts for next-generation sustainable energy conversion and storage.

6.
Antiviral Res ; 200: 105289, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35301060

RESUMO

For human immunodeficiency virus 1 (HIV-1) to infect non-dividing cells, pre-integration complex (PIC) must be transported into the nucleus within the replication cycle. We previously reported that the karyopherin ß1 (KPNB1)-nucleoporin Pom121 pathway, related to the downstream process of PIC nuclear import, mediates efficient HIV-1 PIC nuclear import. Further, our earlier RNA transcriptome sequencing revealed that karyopherin α2 (KPNA2) was among the differentially expressed importin family members during monocyte to macrophage differentiation. Although PIC transport into the nucleus in HIV-1 has been widely studied, much remains to be understood about it. In this study, we confirmed our previous RNA sequencing results and found that HIV-1 replication was significantly lower in 293T cells with siRNA-mediated KPNA2 knockdown and higher in KPNA2-upregulated cells. Quantitative PCR indicated that viral replication was impaired during cDNA nuclear import. The N-terminal of the capsid protein p24 interacted with KPNA2, and KPNB1 participated in KPNA2-mediated PIC nuclear import. Disruption of the capsid-KPNA2 binding by overexpression of full-length p24 or p24 N-terminal impaired the PIC nuclear import. These results indicate that KPNA2 is an important upstream adaptor of the KPNB1-Pom121 axis, thereby mediating HIV-1 PIC nuclear transportation. KPNA2 is thus a potential target for HIV-1 antiviral treatment.


Assuntos
HIV-1 , Transporte Ativo do Núcleo Celular , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Núcleo Celular/metabolismo , HIV-1/genética , HIV-1/metabolismo , Humanos , Carioferinas/metabolismo , Glicoproteínas de Membrana/metabolismo , Replicação Viral , alfa Carioferinas/genética , alfa Carioferinas/metabolismo
7.
Nanotechnology ; 33(23)2022 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-35235915

RESUMO

Carbon nanotube fibers are highly recommended in the field of temperature sensor application owing to their excellent electrical conductivity and thermal conductivity. Here, this work demonstrated the rapid thermal response behaviour of CNT fibers fabricated by floating catalyst CVD method, which was measured by anin situtechnique based on the CNT film electric heater with excellent electrothermal response properties. The temperature dependences of resistance and structure were both explored. Experimental investigation indicates that the reduction in the inter-CNT interspace in the fibers caused by thermally driven actuation was dominantly responsible for the decrease of the fibers resistance during the heating process. Especially, the heated fibers showed 7.2% decrease in electrical resistance at the applied square-wave voltage of 8 V, and good temperature sensitivity (-0.15% °C-1). The as-prepared CNT fibers also featured a rapid and reversible electrical resistance response behaviour when exposed to external heating stimulation. Additionally, with the increment of temperature and twist-degree, the generated contraction actuation increased, which endowed the CNT fibers with more decrease in electrical resistance. These observations further suggested that the temperature-dependent conduction behavior of the CNT fibers with a high reversibility and repeatability was strongly correlated with their structure response to heat stimulation. As a consequence, the temperature-conduction behavior described here may be applied in other CNT-structured fibers and facilitated the improvement in their temperature-sensing applications.

8.
Nanotechnology ; 32(45)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34343978

RESUMO

Exploring bifunctional electrocatalysts with high efficiency, inexpensive, and easy integration is still the daunt challenge for the production of hydrogen on a large scale by means of water electrolysis. In this work, a novel free-standing Co3S4/CoMo2S4heterostructure on nickel foam by a facial hydrothermal method is demonstrated to be an effective bifunctional electrocatalyst for overall water splitting (OWS). The synthesized Co3S4/CoMo2S4electrocatalyst achieves ultralow overpotentials of 143 mV@10 mA cm-2for hydrogen evolution reaction (HER) and 221 mV@25 mA cm-2for oxygen evolution reaction (OER), respectively, in 1 M KOH. Moreover, it presents a greatly improved durability and stability under operando electrochemical conditions. When used as catalysts for OWS, the Co3S4/CoMo2S4-3//Co3S4/CoMo2S4-3 electrodes just need 1.514 V to make it to the current density of 10 mA cm-2. It is supposed that the introduction of heterogeneous interface between Co3S4and CoMo2S4could give rise to plentiful active sites and enhanced conductivity, and thus boost excellent catalytic performances. Moreover, the porous feature of free-standing nanosheets on nickel foam could benefits catalytic performances by accelerating charge transport and releasing bubbles rapidly. This work proposes a bifunctional catalyst system with the heterogeneous interface, which could be used in a sustainable green energy system.

9.
Chem Asian J ; 16(13): 1786-1791, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-33977662

RESUMO

Surface modulation and heteroatom doping are important approaches for boosting the electrocatalytic performances of MoS2 nanosheets. As a molecular electrocatalyst, the natural organic phytic acid (PA) offer attractive intermediate for oxygen evolution reaction (OER). Here, a surface modulation strategy is demonstrated through the decoration of PA onto the basal plane of iron (Fe)-doped MoS2 nanosheets supported on nickel foam (NF) for boosted OER activity. Experimental results indicate that the PA modification and Fe doping could effectively boost the charge transfer and mass transport during the OER process. Specially, PA2-Fe-MoS2 grown on NF (PA2-Fe-MoS2 /NF) exhibits excellent OER activity (218 mV@20 mA cm-2 ) and durability, even superior to RuO2 and many other previously reported OER catalysts. This natural organic molecule modification provides a facile strategy to designing low-cost and efficient electrocatalytic materials.

10.
Curr Microbiol ; 78(2): 490-501, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33386938

RESUMO

GP64 is the key membrane fusion protein of Group I baculovirus, and while the Bombyx mori nucleopolyhedrovirus (BmNPV) GP64 contains a longer n-region (18 amino acid) of the signal peptide than does the Autographa californica multiple nucleopolyhedrovirus (AcMNPV), the function of the n-region has not been determined. In this study, we first showed that n-region is required for membrane protein localization in BmN cells, then the transcriptome sequencing was conducted on proteins guided by different signal peptide regions, and the results were analyzed and validated by quantitative PCR and luciferase assays. The results indicated that 1049 differentially expressed genes (DEGs) were identified among the different region of signal peptides and the control. With the n-region, the protein export pathway was upregulated significantly, the Wnt-1 signaling pathway was downregulated, and BiP was significantly activated by the GP64 full-length signal peptide. Furthermore, RNA interference on BiP efficiently increased luciferase secretion. These results indicate that the GP64 n-region plays a key role in protein expression and regulation.


Assuntos
Bombyx , Sinais Direcionadores de Proteínas , Sequência de Aminoácidos , Aminoácidos , Animais , Proteínas de Transporte , Linhagem Celular , Imunoglobulinas , Nucleopoliedrovírus , Sinais Direcionadores de Proteínas/genética , Análise de Sequência de RNA
11.
Small ; 17(9): e2002240, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32851763

RESUMO

2D metal (hydr)oxide nanosheets have captured increasing interest in electrocatalytic applications aroused by their high specific surface areas, enriched chemically active sites, tunable physiochemical properties, etc. In particular, the electrocatalytic reactivities of materials greatly rely on their surface electronic structures. Generally speaking, the electronic structures of catalysts can be well adjusted via controlling their morphologies, defects, and heterostructures. In this Review, the latest advances in 2D metal (hydr)oxide nanosheets are first reviewed, including the applications in electrocatalysis for the hydrogen evolution reaction, oxygen reduction reaction, and oxygen evolution reaction. Then, the electronic structure-property relationships of 2D metal (hydr)oxide nanosheets are discussed to draw a picture of enhancing the electrocatalysis performances through a series of electronic structure tuning strategies. Finally, perspectives on the current challenges and the trends for the future design of 2D metal (hydr)oxide electrocatalysts with prominent catalytic activity are outlined. It is expected that this Review can shed some light on the design of next generation electrocatalysts.

12.
Virus Genes ; 56(5): 557-563, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32500372

RESUMO

In this study, we investigated drug resistance levels in human immunodeficiency virus (HIV)-1-infected patients in Suzhou by retrospectively analyzing this property and the characteristics of circulating HIV-1 strains collected from 2009 to 2014. A total of 261 HIV-1-positive plasma samples, confirmed by the Suzhou CDC, were collected and evaluated to detect HIV-1 drug resistance genotypes using an in-house method. The pol gene fragment was amplified, and its nucleic acid sequence was determined by Sanger sequencing. Drug resistance mutations were then analyzed using the Stanford University HIV resistance database ( https://hivdb.stanford.edu ). A total of 216 pol gene fragments were amplified and sequenced with 16.7% (36/216) of sequences revealing these mutations. The drug resistance rates of protease, nucleoside reverse transcriptase, and non-nucleoside reverse transcriptase inhibitors (NNRTIs) were 4/36 (11.1%), 2/36 (5.6%), and 30/36 (83.3%), respectively. Five surveillance drug resistance mutations were found in 36 sequences, of which, three were found among specimens of men who have sex with men. Potential low-level resistance accounted for 33% of amino acid mutations associated with NNRTIs. Two of the mutations, M230L and L100I, which confer a high level of resistance efavirenz (EFV) and nevirapine (NVP) used as NNRTIs for first-line antiretroviral therapy (ART), were detected in this study. Therefore, when HIV-1 patients in Suzhou are administered fist-line ART, much attention should be paid to the status of these mutations that cause resistance to EVP, EFV, and NVP.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Farmacorresistência Viral/genética , Infecções por HIV , HIV-1 , Adulto , China/epidemiologia , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Estudos Retrospectivos , Adulto Jovem
13.
Biochem Biophys Res Commun ; 527(2): 453-457, 2020 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-32336542

RESUMO

Blockade of the PD-1/PD-L1 axis using antibody drugs has been a clinically efficacious immunotherapy in cancer treatment. However, studies on peptide inhibitors blocking the interaction between PD-1/PD-L1 in cancer treatment in clinical practice have not yet been reported. In this study, a series of peptide inhibitors were synthesized based on a continuous sequence of 14 amino acids from PD-L1 and suitable modifications to form a hairpin structure. The effect of inhibitors on the blockage of PD-1/PD-L1 by increasing the stability of the hairpin structure was determined using BLI and co-culture models. The results showed that increasing the stability of the hairpin improved the affinity of inhibitors to PD-1 and increased IL-2 secretion. Therefore, modifying the hairpin structure of peptide inhibitors may be a useful approach to block the interaction between PD-1 and PD-L1.


Assuntos
Antígeno B7-H1/metabolismo , Peptídeos/química , Peptídeos/farmacologia , Receptor de Morte Celular Programada 1/metabolismo , Mapas de Interação de Proteínas/efeitos dos fármacos , Sequência de Aminoácidos , Antígeno B7-H1/antagonistas & inibidores , Células HCT116 , Humanos , Modelos Moleculares , Receptor de Morte Celular Programada 1/antagonistas & inibidores
14.
Nanoscale ; 11(29): 13909-13916, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31304941

RESUMO

Mechanically strong carbon nanotube (CNT) fibers have increasingly become the focus of the present research in the fiber industry. However, the weak or even a lack of interconnections between adjacent CNTs induces much inter-tube slippages during fiber failure, and thus results in their low mechanical strength. Moreover, achieving fast cross-linking between neighbouring CNTs on a large scale to prevent the failure by slip is still a big challenge. Herein we report an ultrafast and continuous tension-annealing process to achieve the considerably improved tube alignment and strong covalent cross-linking of neighbouring CNTs in milliseconds, resulting in great improvement of the fiber performance. The CNT fibers were heated to high temperature (∼2450 °C) by Joule heating under the applied tension and subsequently annealed for just 12 ms. Due to the rapid electromechanical response of the fibers, instant nanotube rearrangements coupled by the formation of cross-links robustly bonding the adjacent CNTs occurred at power-on, which could be attributed to the considerable increases of strength and modulus by factors of 2.9 (up to 3.2 GPa) and 4.8 (up to 123 GPa), respectively. The resultant fibers showed high specific strength (2.2 N per tex), comparable with that of PAN-based carbon fibers, and high specific electrical conductivity higher than that of PAN-based carbon fibers. Moreover, the obtained strongly crosslinked and highly dense structures also endowed the fibers with the significantly improved thermal stability under a high-temperature oxidation atmosphere. Moreover, a continuous tension-annealing process was designed to achieve the large scale production of high performance fibers with the average strength of 2.2 GPa. The high-toughness, lightweight and continuous features together with their outstanding mechanical and electrical properties would certainly boost the large-scale applications of CNT fibers.

15.
Int J Mol Sci ; 20(6)2019 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-30917579

RESUMO

Type 2 diabetes mellitus (T2DM) is associated with pancreatic ß-cell dysfunction which can be induced by oxidative stress. Deuterohemin-ßAla-His-Thr-Val-Glu-Lys (DhHP-6) is a microperoxidase mimetic that can scavenge reactive oxygen species (ROS) in vivo. In our previous studies, we demonstrated an increased stability of linear peptides upon their covalent attachment to porphyrins. In this study, we assessed the utility of DhHP-6 as an oral anti-diabetic drug in vitro and in vivo. DhHP-6 showed high resistance to proteolytic degradation in vitro and in vivo. The degraded DhHP-6 product in gastrointestinal (GI) fluid retained the enzymatic activity of DhHP-6, but displayed a higher permeability coefficient. DhHP-6 protected against the cell damage induced by H2O2 and promoted insulin secretion in INS-1 cells. In the T2DM model, DhHP-6 reduced blood glucose levels and facilitated the recovery of blood lipid disorders. DhHP-6 also mitigated both insulin resistance and glucose tolerance. Most importantly, DhHP-6 promoted the recovery of damaged pancreas islets. These findings suggest that DhHP-6 in physiological environments has high stability against enzymatic degradation and maintains enzymatic activity. As DhHP-6 lowered the fasting blood glucose levels of T2DM mice, it thus represents a promising candidate for oral administration and clinical therapy.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hemina/análogos & derivados , Hipoglicemiantes/uso terapêutico , Oligopeptídeos/uso terapêutico , Administração Oral , Animais , Células CACO-2 , Células Cultivadas , Hemina/administração & dosagem , Hemina/farmacocinética , Hemina/uso terapêutico , Humanos , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/farmacocinética , Secreção de Insulina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oligopeptídeos/administração & dosagem , Oligopeptídeos/farmacocinética , Ratos , Ratos Wistar
16.
J Nanosci Nanotechnol ; 19(6): 3288-3292, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30744755

RESUMO

The bifunctional drug delivery system combining magnetic nanoparticles and fluorophore possesses the characterization of magnetism and fluorescence. However, the accurate tracing of the drug release and diffusion pathway is affected by the separation of drug and fluorescent molecule. In this paper, we synthesized the fluorescent-labeling drug by covalently binding Aspirin with rare earth ions Terbium (Te) and Gadolinium (Gd), which was incorporated into chitosan microspheres with magnetic nanoparticles Fe3O4 to prepare magnetic and fluorescent drug delivery system. Investigated by Fourier transform infrared spectrometer, fluorescence spectrophotometer, X-ray diffraction, vibrating sample magnetometer, and scanning electron microscopy, the chitosan microspheres showed excellent fluorescent and magnetic properties. Compared with the single rare earth ion complex, the multiple rare earth ions complexes with Aspirin TbxGd1-x(Aspirin)3 · 2H2O (x 0.25, 0.5, 0.75) exhibited superior fluorescent intensity.


Assuntos
Quitosana , Nanopartículas de Magnetita , Preparações Farmacêuticas , Sistemas de Liberação de Medicamentos , Íons , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
17.
Nanoscale ; 11(10): 4585-4590, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30809624

RESUMO

Carbon nanotube (CNT) fibers are strong, flexible, and multifunctional, which makes them promising candidates for use at extreme temperatures. However, the current reported mechanical properties of CNT fibers were commonly obtained at room temperature. Here, we report the measurement of the mechanical properties of CNT fibers at temperatures ranging from -196 °C to 2400 °C. Compared with the room temperature strength and modulus, CNT fibers tested at 1000 °C and 2400 °C retained 82% and 54% of the strength, and 71% and 50% of the modulus, respectively, while 68% and 220% increases in the strength and modulus, respectively, were observed for CNT fibers tested at -196 °C. We attributed the decay in the mechanical properties at high temperatures to the weakening of individual nanotubes and intertube interactions, and the strength enhancement at low temperature to the increased activation energy to break the nanotubes. The present study provides the fundamental mechanical properties of CNT fibers at extreme temperatures, which could facilitate the applications of CNT fibers in aeronautics and astronautics where extreme temperature conditions commonly exist.

18.
Bioorg Chem ; 82: 332-339, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30428413

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative brain disease and is the most common cause of dementia in the elderly. The main hallmark of AD is the deposition of insoluble amyloid (Aß) outside the neuron, leading to amyloid plaques and neurofibrillary tangles in the brain. Deuterohemin-Ala-His-Thr-Val-Glu-Lys (DhHP-6), a novel porphyrin-peptide, has both microperoxidase activity and cell permeability. In the present study, DhHP-6 efficiently inhibited the aggregation of Aß and reduced the ß-sheet percentage of Aß from 89.1% to 78.3%. DhHP-6 has a stronger affinity (KD = 100 ±â€¯12 µM) for binding with Aß at Phe4, Arg5, Val18, Glu11 and Glu22. In addition, DhHP-6 (100 µM) significantly prolonged lifespan, alleviated paralysis and reduced Aß plaque formation in the Aß1-42 transgenic Caenorhabditis elegans CL4176 model of AD. Our results demonstrate that DhHP-6 is a potential drug candidate that efficiently protects a transgenic C. elegans model of Alzheimer's disease by inhibiting Aß aggregation.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Caenorhabditis elegans/química , Sequestradores de Radicais Livres/farmacologia , Hemina/análogos & derivados , Oligopeptídeos/farmacologia , Fragmentos de Peptídeos/metabolismo , Multimerização Proteica/efeitos dos fármacos , Peptídeos beta-Amiloides/genética , Animais , Animais Geneticamente Modificados , Materiais Biomiméticos/farmacologia , Caenorhabditis elegans/genética , Hemina/farmacologia , Longevidade/efeitos dos fármacos , Simulação de Acoplamento Molecular , Paralisia/tratamento farmacológico , Fragmentos de Peptídeos/genética , Peroxidases/química , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta
19.
Small ; 14(48): e1803409, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30334376

RESUMO

As a promising energy-storage device, rechargeable Zn-air batteries have attracted considerable interests. Herein, a bifunctional oxygen electrode film prepared by adhering NiCo2 O4 nanosheets to a nitrogen and oxygen dual-doped carbon nanotubes film in a large scale is reported. The resulting self-supporting film electrode is multifunctional, which integrates a porous conducting structure for air diffusion and charge transfer, high-performance catalysts for oxygen reduction and evolution, and novel structural flexibility. The composite film demonstrates excellent oxygen reduction/evolution reaction catalytic activities with low Tafel slopes (50 mV dec-1 for oxygen reduction reaction; 92 mV dec-1 for oxygen evolution reaction). Without any additional current collector, gas diffusion layer, or binder, the obtained bifunctional film performs as an "all-in-one" air electrode in a Zn-air battery. A 50-cm-long cable-shaped Zn-air battery based on such a film air electrode exhibits high operating potentials (≈1.2 V at 0.25 mA cm-2 ), low charging-discharging overpotentials (≈0.7 V), and stable cycling performance. Moreover, the flexible cable Zn-air batteries show excellent stability under different deformation conditions. The proposed concept of constructing scalable, all-in-one, freestanding, and flexible air electrodes would pave the way to develop next-generation wearable and portable energy-storage devices.

20.
J Nanosci Nanotechnol ; 18(12): 8094-8098, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30189924

RESUMO

The drug delivery system incorporating magnetic particles and fluorescent marker would be uniquely effective for magnetic targeting and fluorescent tracing. In order for the fluorescent signals to reflect the drug delivery accurately, the separation of the fluorescent label and drugs must be counteracted. The objective of the current study was to design a method of binding drugs to the fluorescent material so that the drug diffusion and delivery could be monitored precisely. To obtain fluorescently-labeled drugs, complexes of the rare earth ion with a single drug benzimidazole (Tb(Bim)3), and with combined drugs benzimidazole and aspirin (TbBim(Asp)2) were generated. Subsequently, the magnetic nanoparticles Fe3O4 and TbBim(Asp)2 were encapsulated in chitosan microspheres to prepare magnetic fluorescent bifunctional drug delivery system Fe3O4/TbBim(Asp)2/Chitosan. The intermediate and final products were analyzed by spectroscopy, X-ray diffraction, magnetometry, and electron microscopy, documenting that the newly developed drug-containing nanoparticles exhibited desirable fluorescent, magnetic, and morphologic properties.


Assuntos
Quitosana , Sistemas de Liberação de Medicamentos , Nanopartículas de Magnetita , Preparações Farmacêuticas , Portadores de Fármacos , Magnetismo , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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