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1.
Nature ; 593(7857): 83-89, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33953408

RESUMO

The Paris Agreement aims to limit global mean warming in the twenty-first century to less than 2 degrees Celsius above preindustrial levels, and to promote further efforts to limit warming to 1.5 degrees Celsius1. The amount of greenhouse gas emissions in coming decades will be consequential for global mean sea level (GMSL) on century and longer timescales through a combination of ocean thermal expansion and loss of land ice2. The Antarctic Ice Sheet (AIS) is Earth's largest land ice reservoir (equivalent to 57.9 metres of GMSL)3, and its ice loss is accelerating4. Extensive regions of the AIS are grounded below sea level and susceptible to dynamical instabilities5-8 that are capable of producing very rapid retreat8. Yet the potential for the implementation of the Paris Agreement temperature targets to slow or stop the onset of these instabilities has not been directly tested with physics-based models. Here we use an observationally calibrated ice sheet-shelf model to show that with global warming limited to 2 degrees Celsius or less, Antarctic ice loss will continue at a pace similar to today's throughout the twenty-first century. However, scenarios more consistent with current policies (allowing 3 degrees Celsius of warming) give an abrupt jump in the pace of Antarctic ice loss after around 2060, contributing about 0.5 centimetres GMSL rise per year by 2100-an order of magnitude faster than today4. More fossil-fuel-intensive scenarios9 result in even greater acceleration. Ice-sheet retreat initiated by the thinning and loss of buttressing ice shelves continues for centuries, regardless of bedrock and sea-level feedback mechanisms10-12 or geoengineered carbon dioxide reduction. These results demonstrate the possibility that rapid and unstoppable sea-level rise from Antarctica will be triggered if Paris Agreement targets are exceeded.

2.
Nat Prod Res ; : 1-6, 2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33908316

RESUMO

A new aryltetralin lignan, bupleroid A (1), along with ten known analogues (2-11) were isolated from Bupleurum marginatum. The structures of these isolates were determined by 1D and 2D NMR, HRESIMS, and ECD data analysis. In addition, the DPPH radical scavenging capacities of all compounds were evaluated. Compound 6 exhibited good DPPH radical scavenging activity at a concentration of 50 µM.

3.
Nanoscale ; 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33876163

RESUMO

Durability is a crucial feature to expand the application field of artificial superhydrophobic coatings. Herein, a kind of durable superhydrophobic coating is prepared by a simple and cheap method using a fluorine-free suspension as the raw material, which consists of epoxy modified silicone resin (MSR), functionalized SiO2, GO, and lamellar mica powder (MP). The MSR@SiO2 + GO + MP coating shows outstanding surface wettability with a water contact angle of 163.8°, a low sliding angle of 3.5° and the microdroplet adhesive force of about 12.6 ± 0.5 µN. Furthermore, it can withstand alternating high and low temperatures, intense UV radiation for 7 days, strong chemical attack, and various mechanical durability tests. In addition, the coating also exhibits a significantly repairable ability to resist O2 plasma etching, and outstanding self-cleaning both in air and oil even after mechanical damage. The mechanism for the influence of the multiple hybridizations on the long-term corrosion stability and thermal-related properties of the superhydrophobic coating is further systematically studied. The simple method and superhydrophobic coating should have good application prospects in large area protection.

4.
Artigo em Inglês | MEDLINE | ID: mdl-33904301

RESUMO

Nanofiber membranes via electrospinning with layered structures are frequently used for oil/water separation, thanks to their unique properties. However, challenges that involve nanofibrous membranes still remain, such as high energy consumption and unfavorable transport properties because of the densely compact structure. In this study, superelastic and robust nanofiber-based aerogels (NFAs) with a three-dimensional (3D) structure as well as tunable porosity were prepared using polyimide (PI) nanofibers via a freeze-drying process followed by the solvent-vapor treatment. The porous NFAs were further modified using trichloromethylsilane (TCMS) to generate silicone nanofilaments (SiNFs) on the surface of the PI nanofibers, which could enhance the hydrophobicity (water contact angle 151.7°) of the NFAs. The corresponding superhydrophobic NFAs exhibited ultralow density (<10.0 mg m-3), high porosity (>99.0%), and rapid recovery under 80% compression strain. SiNFs-coated NFAs (SiNFs/NFAs) could also collect a wide range of oily solvents with high absorption capacities up to 159 times to their own weight. Moreover, surfactant-stabilized water-in-oil emulsions could also be efficiently separated (up to 100%) under the driving force of gravity, making it a promising energy-efficient technology. Additionally, SiNFs/NFAs maintained high separation efficiency throughout five separation-recovery cycles, indicating the potential of SiNFs/NFAs in the field of oil/water separation, sewage treatment, as well as oily fume purification.

5.
Sci Rep ; 11(1): 8412, 2021 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-33863958

RESUMO

A reasonable prediction of infectious diseases' transmission process under different disease control strategies is an important reference point for policy makers. Here we established a dynamic transmission model via Python and realized comprehensive regulation of disease control measures. We classified government interventions into three categories and introduced three parameters as descriptions for the key points in disease control, these being intraregional growth rate, interregional communication rate, and detection rate of infectors. Our simulation predicts the infection by COVID-19 in the UK would be out of control in 73 days without any interventions; at the same time, herd immunity acquisition will begin from the epicentre. After we introduced government interventions, a single intervention is effective in disease control but at huge expense, while combined interventions would be more efficient, among which, enhancing detection number is crucial in the control strategy for COVID-19. In addition, we calculated requirements for the most effective vaccination strategy based on infection numbers in a real situation. Our model was programmed with iterative algorithms, and visualized via cellular automata; it can be applied to similar epidemics in other regions if the basic parameters are inputted, and is able to synthetically mimic the effect of multiple factors in infectious disease control.


Assuntos
/diagnóstico , Modelos Teóricos , /epidemiologia , /virologia , Humanos , Prognóstico , Reino Unido/epidemiologia , Vacinação/psicologia
6.
Anal Chem ; 93(15): 6112-6119, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33821620

RESUMO

Sensitivity-improved versions of two-dimensional (2D) 13C-1H HSQC (heteronuclear single quantum coherence) and HSQC-TOCSY (HSQC-total correlation spectroscopy) NMR experiments optimized for small biological molecules and their complex mixtures encountered in metabolomics are presented that preserve the magnetization of 1H spins not directly attached to 13C spins. This allows (i) the application of rapid acquisition techniques to substantially shorten measurement time and (ii) their incorporation into supersequences (NOAH-NMR by ordered acquisition using 1H detection) for the compact acquisition of multiple 2D NMR data sets with significant gains in sensitivity, resolution, and/or time. The new pulse sequences, which are demonstrated for both metabolite model mixtures and mouse urine, offer an attractive approach for the efficient measurement of multiple 2D NMR spectra (HSQCsi and/or HSQCsi-TOCSY and TOCSY) of metabolomics samples in a single experiment for the accurate and comprehensive identification and quantitation of metabolites. These new methods bring to bear the advantages of 2D NMR to metabolomics studies with larger cohorts of samples.

7.
Nanomaterials (Basel) ; 11(3)2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33809597

RESUMO

To speed up the fabrication of optical metamaterials by making use of the fast speed advantage of femtosecond laser preparation, a metamaterial appropriate for femtosecond laser processing was designed, and the interaction between femtosecond laser and metal-dielectric-metal fishnet stacks was investigated in detail. Two kinds of processing mechanisms, thermal melting and stress break, were revealed during the fabrication. The thermal melting process, dominated by the interaction of femtosecond laser with metals, makes the upper and lower metal layers adhere to each other, which leads to the magnetic resonance impossible. The stress break process, dominated by the interaction of femtosecond laser with dielectrics, can keep the upper and lower metal coatings isolated. Fishnet optical metamaterial was fabricated by femtosecond laser-induced stress break technique, using back side ablation, high numerical aperture and super-Gaussian beam. The resolution and speed can reach 500 nm, and 100 units/s, respectively. Spectrophotometer measurement results proved that the magnetic resonances were found in the fishnet nanostructure. The theoretical refractive index of the metamaterial on a glass substrate reached -0.12 at the wavelength of 3225 nm. It proved that femtosecond laser-induced stress break was a good and fast tool during the fabrication of optical metamaterials.

8.
PLoS One ; 16(3): e0245677, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33725016

RESUMO

Musk is a secretion of the forest musk deer (Moschus berezovskii). Normal musk is a brown solid secretion with a light fragrance. In this study, abnormal types of musk, namely, white and black musks, were discovered during the musk collection process. Researchers have long been concerned with the components of musk. Herein, GC-MS, headspace solid-phase microextraction (HS-SPME), and nonmetric multidimensional scaling (NMDS) were used to analyze the nonpolar organic components, volatile organic components, and sample similarities among different musks, respectively. Abundant steroid hormones and proteins were also found in the musk. The steroid hormone concentrations were detected using a radioimmunoassay (RIA). Proteins in the samples were hydrolyzed and the amino acids concentrations were detected. The steroid hormone and amino acid concentrations in white musk were significantly lower than in normal and black musks (p<0.05). The components were subjected to NMDS analysis to understand the differences in components among different types of musk, with the results suggesting that white musk was different from normal and black musks.

9.
Front Public Health ; 9: 616963, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33634067

RESUMO

Background: This study was to collect clinical features and computed tomography (CT) findings of Influenza-Like Illness (ILI) cases, and to evaluate the correlation between clinical data and the abnormal chest CT in patients with the Influenza-Like Illness symptoms. Methods: Patients with the Influenza-Like Illness symptoms who attended the emergency department of The Six Medical Center of The PLA General Hospital from February 10 to April 1, 2020 were enrolled. Clinical and imaging data of the enrolled patients were collected and analyzed. The association between clinical characteristics and abnormal chest CT was also analyzed. Results: A total of 148 cases were enrolled in this study. Abnormalities on chest CT were detected in 61/148 (41.2%) patients. The most common abnormal CT features were as follows: patchy consolidation 22/61(36.1%), ground-glass opacities 21/61(34.4%), multifocal consolidations 17/61(27.9%). The advanced age and underlying diseases were significantly associated with abnormal chest CT. Conclusions: Abnormal chest CT is a common condition in Influenza-Like Illness cases. The presence of advanced age and concurrent underlying diseases is significantly associated with abnormal chest CT findings in patients with ILI symptoms. The chest CT characteristic of ILI is different from the manifestation of COVID-19 infection, which is helpful for differential diagnosis.


Assuntos
Diagnóstico Diferencial , Influenza Humana/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Influenza Humana/fisiopatologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Radiografia Torácica , Estudos Retrospectivos
10.
Viruses ; 13(2)2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33557409

RESUMO

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality. Almost half of HCC cases are associated with hepatitis B virus (HBV) infections, which often lead to HBV sequence integrations in the human genome. Accurate identification of HBV integration sites at a single nucleotide resolution is critical for developing a better understanding of the cancer genome landscape and of the disease itself. Here, we performed further analyses and characterization of HBV integrations identified by our recently reported VIcaller platform in recurrent or known HCC genes (such as TERT, MLL4, and CCNE1) as well as non-recurrent cancer-related genes (such as CSMD2, NKD2, and RHOU). Our pathway enrichment analysis revealed multiple pathways involving the alcohol dehydrogenase 4 gene, such as the metabolism pathways of retinol, tyrosine, and fatty acid. Further analysis of the HBV integration sites revealed distinct patterns involving the integration upper breakpoints, integrated genome lengths, and integration allele fractions between tumor and normal tissues. Our analysis also implies that the VIcaller method has diagnostic potential through discovering novel clonal integrations in cancer-related genes. In conclusion, although VIcaller is a hypothesis free virome-wide approach, it can still be applied to accurately identify genome-wide integration events of a specific candidate virus and their integration allele fractions.


Assuntos
Carcinoma Hepatocelular/genética , Vírus da Hepatite B/genética , Neoplasias Hepáticas/genética , Integração Viral , Carcinogênese/genética , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/virologia , DNA Viral/genética , Frequência do Gene , Genoma Humano/genética , Genoma Viral/genética , Vírus da Hepatite B/fisiologia , Hepatite B Crônica/genética , Hepatite B Crônica/patologia , Hepatite B Crônica/virologia , Humanos , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/virologia , Software
11.
Cell Prolif ; 54(4): e13005, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33594777

RESUMO

PURPOSE: We investigated the role of farnesoid X receptor (FXR), a ligand-dependent transcription factor, in renal ischaemia-reperfusion (I/R) injury. MATERIALS AND METHODS: We performed unilateral renal I/R model in FXR knockout (Fxr-/- ) and wild-type (WT) mice in vivo and a hypoxia-reoxygenation (H/R) model in vitro. The pathways by which FXR induces apoptosis were detected using a proteome profiler array. The effects of FXR on apoptosis were evaluated using immunoblotting, TUNEL assays and flow cytometry. RESULTS: Compared with WT mice, Fxr-/- mice showed improved renal function and reduced tubular injury scores and apoptosis. Consistent with the in vivo results, the silencing of FXR decreased the number of apoptotic HK-2 cells after H/R, while FXR overexpression aggravated apoptosis. Notably, bone marrow transplantation (BMT) and immunohistochemistry experiments revealed the involvement of FXR in the tubular epithelium rather than in inflammatory cells. Furthermore, in vivo and in vitro studies demonstrated that FXR deficiency increased phosphorylated Bcl-2 agonist of cell death (p-Bad) expression levels and the ratio of Bcl-2/Bcl-xL to Bax expression in the kidney. Treatment with wortmannin, which reduced p-Bad expression, inhibited the effects of FXR deficiency and eliminated the tolerance of Fxr-/- mouse kidneys to I/R injury. CONCLUSIONS: These results established the pivotal importance of FXR inactivation in tubular epithelial cells after I/R injury. FXR may promote the apoptosis of renal tubular epithelial cells by inhibiting PI3k/Akt-mediated Bad phosphorylation to cause renal I/R damage.


Assuntos
Apoptose , Receptores Citoplasmáticos e Nucleares/metabolismo , Traumatismo por Reperfusão/patologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Rim/metabolismo , Rim/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Receptores Citoplasmáticos e Nucleares/genética , Traumatismo por Reperfusão/metabolismo , Transdução de Sinais/efeitos dos fármacos , Wortmanina/farmacologia , Proteína X Associada a bcl-2/metabolismo , Proteína bcl-X/metabolismo
12.
Plant Physiol ; 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33576790

RESUMO

Protein phosphorylation is a common post-translational modification that frequently occurs during plant-virus interaction. Host protein kinases often regulate virus infectivity and pathogenicity by phosphorylating viral proteins. The Barley stripe mosaic virus (BSMV) γb protein plays versatile roles in virus infection and the coevolutionary arms race between plant defense and viral counter-defense. Here, we identified that the autophosphorylated cytosolic serine/threonine/tyrosine (STY) protein kinase 46 of Nicotiana benthamiana (NbSTY46) phosphorylates and directly interacts with the basic motif domain (aa 19-47) of γb in vitro and in vivo. Overexpression of wild-type NbSTY46, either transiently or transgenically, suppresses BSMV replication and ameliorates viral symptoms, whereas silencing of NbSTY46 leads to increased viral replication and exacerbated symptom. Moreover, the antiviral role of NbSTY46 requires its kinase activity, as the NbSTY46T436A mutant, lacking kinase activity, not only loses the ability to phosphorylate and interact with γb but also fails to impair BSMV infection when expressed in plants. NbSTY46 could also inhibit the replication of Lychnis ringspot virus, another chloroplast-replicating hordeivirus. In summary, we report a function of the cytosolic kinase STY46 in defending against plant viral infection by phosphorylating a viral protein in addition to its basal function in plant growth, development, and abiotic stress responses.

13.
J Magn Reson Imaging ; 2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33604934

RESUMO

BACKGROUND: Noncontrast cardiac T1 times are increased in dialysis patients which might indicate fibrotic alterations in uremic cardiomyopathy. PURPOSE: To explore the application of the texture analysis (TA) of T1 images in the assessment of myocardial alterations in dialysis patients. STUDY TYPE: Case-control study. POPULATION: A total of 117 subjects, including 22 on hemodialysis, 44 on peritoneal dialysis, and 51 healthy controls. FIELD STRENGTH: A 3 T, steady-state free precession (SSFP) sequence, modified Look-Locker imaging (MOLLI). ASSESSMENT: Two independent, blinded researchers manually delineated endocardial and epicardial borders of the left ventricle (LV) on midventricular T1 maps for TA. STATISTICAL TESTS: Texture feature selection was performed, incorporating reproducibility verification, machine learning, and collinearity analysis. Multivariate linear regressions were performed to examine the independent associations between the selected texture features and left ventricular function in dialysis patients. Texture features' performance in discrimination was evaluated by sensitivity and specificity. Reproducibility was estimated by the intraclass correlation coefficient (ICC). RESULTS: Dialysis patients had greater T1 values than normal (P < 0.05). Five texture features were filtered out through feature selection, and four showed a statistically significant difference between dialysis patients and healthy controls. Among the four features, vertical run-length nonuniformity (VRLN) had the most remarkable difference among the control and dialysis groups (144 ± 40 vs. 257 ± 74, P < 0.05), which overlap was much smaller than Global T1 times (1268 ± 38 vs. 1308 ± 46 msec, P < 0.05). The VRLN values were notably elevated (cutoff = 170) in dialysis patients, with a specificity of 97% and a sensitivity of 88%, compared with T1 times (specificity = 76%, sensitivity = 60%). In dialysis patients, VRLN was significantly and independently associated with left ventricular ejection fraction (P < 0.05), global longitudinal strain (P < 0.05), radial strain (P < 0.05), and circumferential strain (P < 0.05); however, T1 was not. DATA CONCLUSION: The texture features obtained by TA of T1 images and VRLN may be a better parameter for assessing myocardial alterations than T1 times. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 3.

14.
J Neuroimmunol ; 353: 577515, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33640718

RESUMO

The spectrum of anti-contactin-associated protein-like 2 (CASPR2) antibody-associated disease is expanding and the involvement of cerebellum was reported in the past few years. We report a 45-year-old male with chronically progressive cerebellar ataxia. CASPR2 antibodies were detected in his serum and cerebellar atrophy was observed on MRI. His symptoms improved prominently with steroids and intravenous immunoglobulins. 23 cases with CASPR2 antibodies and cerebellar ataxia were identified from previous publications. Most of patients showed acute or subacute onset with other typical presentations of anti-CASPR2 antibody-associated disease, such as limbic encephalitis. Immunotherapy was effective in the majority of patients.

15.
Mater Sci Eng C Mater Biol Appl ; 120: 111690, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33545852

RESUMO

Developing multifunctional hydrogels with good mechanical properties, tissue-adhesiveness, self-healing properties and antioxidant, blood clotting and antibacterial properties is highly desirable for biomedical applications. In this study, a series of multifunctional chitosan-based double cross-linked hydrogels were prepared using a facile method based on quaternized chitosan (QCS) and polyacrylamide (PAM) using polydopamine (PDA) as a novel connecting bridge. Investigation on the content of dopamine (DA) and QCS revealed that the catechol-mediated interactions played an important role in the hydrogel properties. Results showed that the hydrogel exhibited the best mechanical properties when QCS = 12 wt% and DA = 0.4 wt%. Tensile and compressive strength was 13.3 kPa and 67.8 kPa, respectively, and the hydrogel presented strong and repeatable tissue-adhesiveness (27.2 kPa) to porcine skin, as well as good stretchability (1154%). At room temperature, the hydrogel exhibited high self-healing efficiency (90% after 2 h of healing). Antibacterial test results showed that the hydrogel killed 99.99% S. aureus and E. coli. Moreover, the vaccarin-loaded hydrogel exhibited a pH-responsive drug release profile with superior cytocompatibility compared to the pure hydrogel. In summary, this strategy combined double cross-linking and catechol-mediated chemistry to shed new light on the fabrication of novel multifunctional hydrogels with desirable mechanical properties, strong tissue adhesiveness and self-healing abilities.

16.
Carbohydr Polym ; 255: 117508, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33436257

RESUMO

Long-lasting and reusable adhesive hydrogels are highly desirable in biomedical and relevant applications, however, its design still remains challenge. Here, a series of plant-inspired adhesive hydrogels were prepared based on Ag/Tannic acid-Cellulose nanofibers (Ag/TA-CNF) triggered reversible quinone/catechol chemistry, which mimicked the long-lasting reductive/oxidative balance in mussels. The dynamic redox system generated catechol groups inner the hydrogel continuously, imparting hydrogels with high and repeatable adhesiveness. Besides, the hydrogel still maintained its high adhesiveness after storing at extreme temperatures for 30 days. Furthermore, to broaden the biomedical applications of the hydrogels, the pre-gel solution with optimal composition was cast onto the surface of vaccarin-loaded electrospun nanofibers to form the bilayer nanocomposite hydrogel (NF@HG) in situ. The NF@HG with the intrinsic properties of the hydrogel layer (e.g. stretchable, adhesive, antioxidant, antifreezing, antidrying, photothermal and antibacterial) exhibited enhanced mechanical properties, sustained drug release and good cytocompatibility, which could be an attractive candidate for wound healing material. Taken together, this study may inspire new aspects for designing reusable and long-lasting adhesive hydrogels according to dynamic catechol chemistry.

17.
J Phys Chem B ; 125(3): 798-804, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33444020

RESUMO

The prevalence of intrinsically disordered proteins (IDPs) and protein regions in structural biology has prompted the recent development of molecular dynamics (MD) force fields for the more realistic representations of such systems. Using experimental nuclear magnetic resonance backbone scalar 3J-coupling constants of the intrinsically disordered proteins α-synuclein and amyloid-ß in their native aqueous environment as a metric, we compare the performance of four recent MD force fields, namely, AMBER ff14SB, CHARMM C36m, AMBER ff99SB-disp, and AMBER ff99SBnmr2, by partitioning the polypeptides into an overlapping series of heptapeptides for which a cumulative total of 276 µs MD simulations were performed. The results show substantial differences between the different force fields at the individual residue level. Except for ff99SBnmr2, the force fields systematically underestimate the scalar 3J(HN,Hα)-couplings due to an underrepresentation of ß-conformations and an overrepresentation of either α- or PPII conformations. The study demonstrates that the incorporation of coil library information in modern MD force fields, as shown here for ff99SBnmr2, provides substantially improved performance and more realistic sampling of the local backbone dihedral angles of IDPs as reflected by the good accuracy of the computed scalar 3J(HN,Hα)-couplings with less than 0.5 Hz error. Such force fields will enable a better understanding of how structural dynamics and thermodynamics influence the IDP function. Although the methodology based on heptapeptides used here does not allow the assessment of potential intramolecular long-range interactions, its computational affordability permits well-converged simulations that can be easily parallelized. This should make the quantitative validation of intrinsic disorder observed in MD simulations of polypeptides with experimental scalar J-couplings widely applicable.

18.
Biosens Bioelectron ; 175: 112918, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33383430

RESUMO

The accurate detection of hydrogen peroxide (H2O2)-involved metabolites plays a significant role in the early diagnosis of metabolism-associated diseases, whereas most of current metabolite-sensing systems are often hindered by low sensitivity, interference of coexisting species, or tedious preparation. Herein, an electrochemistry-regenerated surface-enhanced Raman scattering (SERS) sensor was developed to serve as a universal platform for detecting H2O2-involved metabolites. The SERS sensor was constructed by modifying newly synthesized 2-mercaptohydroquinone (2-MHQ) molecules on the surface of gold nanoparticles (AuNPs) that were electrochemically predeposited on an ITO electrode. Metabolites were detected through the changes in the SERS spectrum as a result of the reaction of 2-MHQ with H2O2 induced by the metabolites. Combining the superiority of SERS fingerprint identification and the specificity of the related enzymatic reactions producing H2O2, the designed SERS sensor was highly selective in detecting glucose and uric acid as models of H2O2-involved metabolite with limits of detection (LODs) of 0.159 µM and 0.0857 µM, respectively. Moreover, the sensor maintained a high SERS activity even after more than 10 electrochemical regenerations within 2 min, demonstrating its effectiveness for the rapid detection of various metabolites with electrochemistry-driven regulation. Importantly, the presented SERS sensor showed considerable practicability for the detection of metabolites in real serum samples. Accordingly, the SERS sensor is a new detection platform for H2O2-involved metabolites detection in biological fluids, which may aid the early diagnosis of metabolism-related diseases.

19.
Phytochemistry ; 183: 112593, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33341664

RESUMO

The roots of Euphorbia fischeriana known as "Langdu" in traditional Chinese medicine have been used for the treatment of tuberculosis in China. Through a bioactive phytochemical investigation of the roots of E. fischeriana, 15 diterpenoids were obtained by various chromatographic techniques. On the basis of wide spectroscopic data, including NMR, UV, IR, HR-ESI-MS, ECD and X-ray crystallography, all of the isolated compounds were elucidated to be ent-abietane diterpenoid analogs, including undescribed eupholides A-H and seven known diterpenoids. In the bioassay for anti-tuberculosis, eupholides F-H moderately inhibited the proliferation of Mycobacterium tuberculosis H37Ra, with the MIC determined to be 50 µM. Furthermore, eupholides G, ent-11α-hydroxyabieta-8(14), 13(15)-dien-16,12α-olide, and jolkinolide F significantly inhibited the lyase activity of human carboxylesterase 2 (HCE 2), with IC50 values of 7.3, 150, and 34.5 nM, respectively.


Assuntos
Antineoplásicos Fitogênicos , Euphorbia , Abietanos/farmacologia , China , Diterpenos/farmacologia , Estrutura Molecular , Raízes de Plantas
20.
Biosens Bioelectron ; 171: 112690, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33049561

RESUMO

Development of reliable Enzymatic Biofuel Cells (EBFC)-based self-powered glucose biosensor for continuous, noninvasive monitoring without restriction on patient's movement is highly recommendable. However, its application to a large extent is limited by the relatively poor stability. Herein, we synthesized a highly flexible electrode for effective enzyme immobilization by encapsulating enzyme into the metal-organic frameworks (MOFs) and robustly anchored to the cellulose acetate (CA) nanofiber membrane. As is well-known, such nanostructured fiber materials are the first time to be synthesized for glucose biosensor, which encapsulated biomolecules in MOFs platform during the MOFs in-situ growth on the nanofiber membranes. The as-proposed biosensor demonstrated excellent stability over 15 h of continuous long-term monitoring. The remarkable stability of assembled self-powered glucose biosensor in this work could inspire the application of enzymatic biosensors in biometrics, chronic disease management and clinical diagnosis.


Assuntos
Técnicas Biossensoriais , Glucose , Estruturas Metalorgânicas , Nanofibras , Celulose/análogos & derivados , Glucose/análise , Humanos
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