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1.
PLoS Comput Biol ; 20(9): e1012415, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39226309

RESUMO

Revealing the relationship between neural network structure and function is one central theme of neuroscience. In the context of working memory (WM), anatomical data suggested that the topological structure of microcircuits within WM gradient network may differ, and the impact of such structural heterogeneity on WM activity remains unknown. Here, we proposed a spiking neural network model that can replicate the fundamental characteristics of WM: delay-period neural activity involves association cortex but not sensory cortex. First, experimentally observed receptor expression gradient along the WM gradient network is reproduced by our network model. Second, by analyzing the correlation between different local structures and duration of WM activity, we demonstrated that small-worldness, excitation-inhibition balance, and cycle structures play crucial roles in sustaining WM-related activity. To elucidate the relationship between the structure and functionality of neural networks, structural circuit gradients in brain should also be subject to further measurement. Finally, combining anatomical data, we simulated the duration of WM activity across different brain regions, its maintenance relies on the interaction between local and distributed networks. Overall, network structural gradient and interaction between local and distributed networks are of great significance for WM.


Assuntos
Memória de Curto Prazo , Modelos Neurológicos , Rede Nervosa , Memória de Curto Prazo/fisiologia , Rede Nervosa/fisiologia , Humanos , Biologia Computacional , Animais , Encéfalo/fisiologia , Simulação por Computador , Neurônios/fisiologia , Potenciais de Ação/fisiologia
2.
Anal Chem ; 96(32): 13174-13184, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39093925

RESUMO

The small molecule epiberberine (EPI) is a natural alkaloid with versatile bioactivities against several diseases including cancer and bacterial infection. EPI can induce the formation of a unique binding pocket at the 5' side of a human telomeric G-quadruplex (HTG) sequence with four telomeric repeats (Q4), resulting in a nanomolar binding affinity (KD approximately 26 nM) with significant fluorescence enhancement upon binding. It is important to understand (1) how EPI binding affects HTG structural stability and (2) how enhanced EPI binding may be achieved through the engineering of the DNA binding pocket. In this work, the EPI-binding-induced HTG structure stabilization effect was probed by a peptide nucleic acid (PNA) invasion assay in combination with a series of biophysical techniques. We show that the PNA invasion-based method may be useful for the characterization of compounds binding to DNA (and RNA) structures under physiological conditions without the need to vary the solution temperature or buffer components, which are typically needed for structural stability characterization. Importantly, the combination of theoretical modeling and experimental quantification allows us to successfully engineer Q4 derivative Q4-ds-A by a simple extension of a duplex structure to Q4 at the 5' end. Q4-ds-A is an excellent EPI binder with a KD of 8 nM, with the binding enhancement achieved through the preformation of a binding pocket and a reduced dissociation rate. The tight binding of Q4 and Q4-ds-A with EPI allows us to develop a novel magnetic bead-based affinity purification system to effectively extract EPI from Rhizoma coptidis (Huang Lian) extracts.


Assuntos
Berberina , Quadruplex G , Berberina/química , Berberina/análogos & derivados , Berberina/farmacologia , Humanos , DNA/química , Ácidos Nucleicos Peptídicos/química
3.
Environ Res ; 252(Pt 1): 118866, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38580002

RESUMO

Mercury (Hg) is known to affect aquatic, terrestrial ecosystems as well as human health, through biomagnification. Mangrove wetlands are potential Hg sinks because of their low tidal velocity, fast sedimentation rate, strong reducing condition and high organic matter content. The spatial and temporal distribution of Hg has been a hot topic of recent studies in mangrove wetlands. In this study, we investigated Hg concentration, accumulation rate and isotopes to reconstruct the Hg pollution history and to differentiate its potential sources in the Gaoqiao mangrove wetland (Guangdong province), which is part of the largest mangrove area in China. We reconstructed a first, continuous, high-resolution Hg pollution history over the last 3000 years in South China. Our findings show that mangrove wetland sediments are more enriched in Hg than the adjacent grasslands. The increased Hg concentration and δ202Hg in recent sediments mirror the enhanced anthropogenic impacts; Hg concentrations in areas with high levels of anthropogenic disturbance are up to 5× higher than the average background value (9.9 ± 1.2 µg kg-1). Compared to mangroves in coastal areas of South China and around the world, the Hg concentration in Gaoqiao is much lower. The significant increase of Hg since the 1950s and the major Hg peak since the 1980s were the evidence of the human activities influences and indicated the possible start date of Anthropocene. After 2007 CE, a decline in Hg pollution occurs due to the effective implementation of the mangrove protection policy. Three potential sources were identified by the Hg isotope traces including urban gaseous Hg, industrial Hg, and regional soil and leaf litter Hg input.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos , Mercúrio , Poluentes Químicos da Água , Áreas Alagadas , China , Mercúrio/análise , Sedimentos Geológicos/análise , Sedimentos Geológicos/química , Poluentes Químicos da Água/análise
4.
Phys Rev E ; 108(1-1): 014205, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37583163

RESUMO

Over the past decade, dynamic schemes have been proposed for the use of bistable systems in the design of logic devices. A bistable system in a noisy background can operate as a reliable logic gate in a moderate noise level, which is called a logical stochastic resonance (LSR). In this paper, we theoretically explore the emergence of LSR in general bistable systems and identify the dynamical mechanisms of LSR. The timescale relationship between the measured time and the mean first-pass time of two-state transitions is a key condition in determining whether the system is reliable. Furthermore, we demonstrate that the stability of the logic operation can be significantly improved by choosing the appropriate filtering method. Low-pass filtered noise-driven systems are more stable than Gaussian white noise. However, band-pass and high-pass filtered noise are harmful to the stability of the system due to the filtering of low-frequency components. Our theoretical and numerical simulation results offer perspectives for the development of logic devices.

5.
J Am Chem Soc ; 145(25): 14143-14154, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37318054

RESUMO

The direct coupling of aldehydes with petrochemical feedstock alkenes and alkynes would represent a practical and streamlined approach for allylation and allenylation chemistry. However, conventional approaches commonly require preactivated substrates or strong bases to generate allylic or propargylic carbanions and only afford branched allylation or propargylation products. Developing a mild and selective approach to access synthetically useful linear allylation and allenylation products is highly desirable, albeit with formidable challenges. We report a strategy using hydrogen evolution reaction (HER) to generate a carbanion from weakly acidic sp3 C-H bonds (pKa ∼ 35-40) under mild reaction conditions, obviating the use of strong bases, Schlenk techniques, and multistep procedures. The cathodically generated carbanion reverses the typical reaction selectivity to afford unconventional isomerizing allylation and allenylation products (125 examples). The generation of carbanions was monitored and identified by in situ ultraviolet-visible (UV-vis) spectroelectrochemistry. Furthermore, we extended this protocol to the generation of other carbanions and their application in coupling reactions between alcohols with carbanions. The appealing features of this approach include mild reaction conditions, excellent functional group tolerance, unconventional chemo- and regioselectivity, and the diverse utility of products, which includes offering direct access to diene luminophores and bioactive scaffolds. We also performed cyclic voltammetry, control experiments, and density functional theory (DFT) calculations to rationalize the observed reaction selectivity and mechanism.

6.
ChemSusChem ; 16(10): e202300211, 2023 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-36815428

RESUMO

There have been few reports on the substituent effect of main-group-element corrole complexes as ligand-centered homogeneous electrocatalysts for the hydrogen evolution reaction (HER). The key to comprehend the catalytic mechanism and develop efficient catalysts is the elucidation of the effects of electronic structure on the performance of energy-related small molecules. In this work, the "push-pull" electronic effect of the substituents on electrocatalytic HER of phosphorus corroles was investigated by using 5,10,15-tris(phenyl) corrole phosphorus (1P), 10-pentafluorophenyl-5,15-bis(phenyl) corrole phosphorus (2P), 10-phenyl-5,15-bis(pentafluorophenyl) corrole phosphorus (3P), 5,10,15-tris(pentafluorophenyl) corrole phosphorus (4P) complexes bearing hydroxyl axial ligands and different numbers of fluorine atoms on the meso-aryl substituents. The results revealed that the catalytic HER activity of phosphorus corroles decreased with the increasing of fluorine atom numbers, it follows in the order 1P>2P>3P>4P. Density functional theory (DFT) calculations show that the corrole 1P has the lowest free energy barrier in catalytic HER.

7.
Bioengineering (Basel) ; 9(10)2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36290516

RESUMO

With the evolution of the pandemic caused by the Coronavirus disease of 2019 (COVID-19), reverse transcriptase-polymerase chain reactions (RT-PCR) have invariably been a golden standard in clinical diagnosis. Nevertheless, the traditional polymerase chain reaction (PCR) is not feasible for field application due to its drawbacks, such as time-consuming and laboratory-based dependence. To overcome these challenges, a microchip-based ultrafast PCR system called SWM-02 was proposed to make PCR assay in a rapid, portable, and low-cost strategy. This novel platform can perform 6-sample detection per run using multiple fluorescent channels and complete an ultrafast COVID-19 RT-PCR test within 40 min. Here, we evaluated the performance of the microdevice using the gradient-diluted COVID-19 reference samples and commercial PCR kit and determined its limit-of-detection (LoD) as 500 copies/mL, whose variation coefficients for the nucleocapsid (N) gene and open reading frame 1 ab region (ORF1ab) gene are 1.427% and 0.7872%, respectively. The system also revealed an excellent linear correlation between cycle threshold (Ct) values and dilution factors (R2 > 0.99). Additionally, we successfully detected the target RNAs and internal gene in the clinical samples by fast PCR, which shows strong consistency with conventional PCR protocol. Hence, with compact dimension, user-friendly design, and fast processing time, SWM-02 has the capability of offering timely and sensitive on-site molecular diagnosis for prevention and control of pathogen transmission.

8.
ChemSusChem ; 15(22): e202201553, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36121337

RESUMO

The economical consideration of using an electrocatalyst in energy-related field, composed of non-precious/sustainable elements is quite noteworthy. In this work, the phosphorus(V) complex of tris-(pentafluorophenyl)corrole [(TPFC)PV (OH)2 ] was reported as electrocatalyst for the hydrogen evolution reaction (HER). The electrochemical studies revealed that the HER experienced a ECEC pathway (E: electron transfer step, C: chemical step), and the possible intermediate [PV ]-H species was suggested. (TPFC)PV (OH)2 displayed excellent HER activity in dimethylformamide (DMF) with trifluoroacetic acid (TFA) as the proton source, and the turnover frequency (TOF) reached 31.75 s-1 at an overpotential of 900 mV. Interestingly, the HER electrocatalytic performance remained extraordinary even applying water as a proton source in acetonitrile/water (v/v=2 : 3), with a TOF of 18.40 mol H 2 ${{_{{\rm H}{_{2}}}}}$ molcat -1 h-1 at an overpotential of 900 mV.


Assuntos
Hidrogênio , Prótons , Fósforo , Catálise , Água
9.
Clin Lab ; 68(5)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35536079

RESUMO

BACKGROUND: Corona virus disease 2019 (COVID-19) is a severe acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Different pooling testing strategies have been applied for the detection of SARS-CoV-2. However, the discrepancies among different pooling strategies are still to be explored. METHODS: The aim of this study was to evaluate the two pooling strategies of collecting respiratory specimens for the detection of SARS-CoV-2 RNA. Two groups of five-sample pools were prepared to evaluate the impact of sample pooling and pooled sampling on test sensitivity, respectively. Viral RNA of coronavirus was extracted with the automation system. The N and ORF1ab genes of SARS-CoV-2 RNA were detected with real-time reverse-transcription PCR. The turnaround time of SARS-CoV-2 testing was analyzed before and after the implement of pooled sampling. RESULTS: The pooled sampling displayed advantages in assay sensitivity over the sample pooling. The implementation of pooled sampling significantly shortened the turnaround time of SARS-CoV-2 testing. CONCLUSIONS: The pooled sampling is an efficient and economical strategy for SARS-CoV-2 detection during the periods of high screening demand in low-prevalence areas.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , COVID-19/epidemiologia , Teste para COVID-19 , Humanos , Prevalência , RNA Viral/genética , Sensibilidade e Especificidade , Manejo de Espécimes
10.
Biopolymers ; 113(2): e23476, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34581432

RESUMO

RNAs form secondary structures containing double-stranded base paired regions and single-stranded regions. Probing, detecting and modulating RNA structures and dynamics requires the development of molecular sensors that can differentiate the sequence and structure of RNAs present in viruses and cells, as well as in extracellular space. In this review, we summarize the recent progress on the development of chemically modified peptide nucleic acids (PNAs) for the selective recognition of double-stranded RNA (dsRNA) sequences over both single-stranded RNA (ssRNA) and double-stranded DNA (dsDNA) sequences. We also briefly discuss the applications of sequence-specific dsRNA-binding PNAs in sensing and stabilizing dsRNA structures and inhibiting dsRNA-protein interactions.


Assuntos
Ácidos Nucleicos Peptídicos , Pareamento de Bases , DNA/química , Conformação de Ácido Nucleico , Ácidos Nucleicos Peptídicos/química , RNA de Cadeia Dupla/genética
11.
Inorg Chem ; 60(12): 8442-8446, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34110813

RESUMO

A set of gold corrole complexes containing four different ß-substituent groups (Br/I/CF3), namely, 4Br-Au, 4I-Au, and 4CF3-Au, were investigated; all showed room temperature phosphorescence. The phosphorescence quantum yields of the corroles were determined using tetraphenylporphyrin as a reference: Φph (4I-Au, 0.75%) > Φph (4Br-Au, 0.64%) > Φph (4CF3-Au, 0.38%). 4CF3-Au exhibited near-IR emission (858 nm, aerobic); absorbance intensity for the Q-band was higher than that for the Soret band. Complex 4I-Au showed a longer phosphorescence lifetime (82 µs) compared to those of 4Br-Au (53 µs) and 4CF3-Au (28 µs; N2, tol). Thermally activated delayed fluorescence (TADF) emission of 4I/Br-Au complexes was observed: stronger emission intensity correlated with increasing temperature. Good negative correlations for 4I/Br-Au were observed between the Soret band absorption energy and the solvent polarizability: excited states of 4I/Br-Au are more polar than their ground states. TD-DFT calculations revealed very fast intersystem crossing (ISC) rate constants, 2.20 × 1012 s-1 (4CF3-Au) > 1.96 × 1011 s-1 (4Br-Au) > 1.15 × 1011 s-1 (4I-Au), and importantly, the reverse intersystem crossing (rISC) rate constants are determined as 1.68 × 107 s-1 (4I-Au) > 2.40 × 103 s-1 (4Br-Au) ≫ 8.09 × 10-8 s-1 (4CF3-Au). The exceptionally low rISC rate constant of 4CF3-Au is attributed to its more steric and deformed structure bearing a larger energy gap between the S1 and T1 states.

12.
Chem Commun (Camb) ; 57(38): 4605-4641, 2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33881055

RESUMO

Main group chemistry is often considered less "dynamic" than transition metal (TM) chemistry because of predictable VSEPR-based central atom geometries, relatively slower redox switching and lack of electronic d-d transitions. However, we delineate what has been made possible with main group chemistry to give it its proper due and up-to-date treatment. The huge untapped potential regarding photophysical properties and functioning hereby spurred us to review a range of corrole reports addressing primarily photophysical trends, synthetic aspects, and important guidelines regarding substitution and inorganic principles. We also look at Ag and Au systems and also consider substitutions such as CF3, halogens, additives and also counterions. Throughout, as well as at the end of this review, we suggest various future directions; further future industrial catalytic and health science research is encouraged.

13.
J Periodontol ; 92(5): 738-747, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-32835432

RESUMO

BACKGROUND: Liquid-phase concentrated growth factor (LPCGF), a new-generation platelet concentrate, may potently stimulate human periodontal ligament (PDL) cells. This study assessed the effectiveness of ethylenediaminetetraacetic acid (EDTA) and/or LPCGF on periodontally diseased root surfaces through their effects on PDL cells. METHODS: Dentin blocks prepared from periodontal teeth were divided into four groups and treated as follows: group I, scaling and root planning (SRP); group II, SRP + EDTA; group III, SRP + LPCGF; and group IV, SRP+EDTA + LPCGF. PDL cells were cultured on dentin blocks, and LPCGF-induced biological effects were evaluated by migration and cell adhesion/proliferation assays. Furthermore, PDL cell differentiation was assessed by real-time polymerase chain reaction (PCR). RESULTS: Significantly more adherent cells were observed in the EDTA, LPCGF and combination treatment groups than in the control group. Root conditioning with EDTA and/or LPCGF enhanced cell proliferation and migration more than SRP did. Compared with the control group, the combined treatment group exhibited significant upregulation of cell differentiation-related genes. Electron microscopy of the tooth surface revealed removal of the smear layer and exposed dentin holes in the EDTA-treated group but not in the control group. CONCLUSION: EDTA and LPCGF application to periodontitis-affected root surfaces forms a surface suitable for cell attachment, growth, migration and differentiation. Thus, LPCGF is promising in clinical periodontics applications. Further studies to support these results are necessary.


Assuntos
Ligamento Periodontal/citologia , Raiz Dentária , Adesão Celular , Diferenciação Celular , Células Cultivadas , Dentina , Ácido Edético/farmacologia , Fibroblastos , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Microscopia Eletrônica de Varredura
14.
Photochem Photobiol Sci ; 19(8): 996-1000, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32662800

RESUMO

Toluene, p-xylene and mesitylene were cleanly converted to their corresponding monoaldehydes via mild photooxygenation utilizing transition metal and main group ß-CF3-substituted corroles. Aldehyde yield increased as more electron-donating CH3 groups are present on the substrate. 4-P was most efficient (TON ∼ 1072, mesitylene) via the singlet oxygen vis the superoxide mechanism.

15.
J Obes ; 2020: 2962138, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32148952

RESUMO

Objective: To examine the gender, age, and region of residence in the anthropometric and nutritional profiles of children and adolescents aged 6-18 in Henan Province, China's third most populous province. Design: This cross-sectional study of the China National Nutrition and Health survey (2010-2013) used a multistage cluster sampling technique. The sample included Chinese schoolchildren and adolescents aged 6 to 18 years (1,660 boys and 1,561 girls). Multiple logistic regression models were used to estimate the associations between sociodemographic correlates and overweight or obesity and stunting. Setting. Nine districts/counties in Henan Province. Participants. 3,221 subjects completed the questionnaire. Sociodemographic information was obtained. Body weight and height were measured. Results: There were statistically significant regional differences in average height and weight for boys in all age groups. Girls followed the same trends except for height when 15-18 years old. The urban-rural residence differences were found in relation to prevalence of stunting and weight status. Subjects in poor rural areas (15.43%) and ordinary rural areas (15.34%) had higher rates of stunting compared to their urban counterparts. Prevalence of overweight or obesity was highest in big city areas (15.71%) and lowest in ordinary rural areas (6.37%). Being a boy (OR = 1.69, 95% CI = 1.314-2.143), living in a big city (OR = 2.10, 95% CI = 1.431-3.073), or in a small-medium city (OR = 2.28, CI = 1.606-3.247), or being in a younger age group was associated with being overweight or obese. In addition, being a boy, living in a big city, or in a small-medium city, or being younger in age meant they were less likely to be stunted. Conclusions: A substantial dual burden of malnutrition among children and adolescents in Henan Province was revealed. The urban-rural differences in nutritional status were found. Stunting was more prevalent in rural areas than in urban. In contrast, while the rising problem of childhood and adolescent obesity still exists in the big city, we also found a great spike in obesity in small-medium cities. Evidence also indicated that boys were more likely to be overweight or obese. Our findings suggest that nutrition education, as well as environmental and policy interventions, is needed to target specific geographic regions.


Assuntos
Transtornos do Crescimento , Desnutrição/epidemiologia , Adolescente , Antropometria , Índice de Massa Corporal , Criança , China , Demografia , Feminino , Humanos , Modelos Logísticos , Masculino , Desnutrição/fisiopatologia , Inquéritos Nutricionais , Sobrepeso/epidemiologia , Sobrepeso/fisiopatologia , Obesidade Infantil/epidemiologia , Obesidade Infantil/fisiopatologia , Prevalência , População Rural , Fatores Socioeconômicos , Inquéritos e Questionários , População Urbana
16.
Wei Sheng Yan Jiu ; 48(6): 892-897, 2019 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-31875811

RESUMO

OBJECTIVE: To analyze the height, weight and BMI of children and adolescents aged 6-17 in different sex, age and area in Henan Province from 2010 to2013. METHODS: Based on the monitoring of nutrition and health status of Chinese residents conducted in 9 urban and rural monitoring points in Henan Province from October 2010 to December 2013, 3221 aged 6-17 children and adolescents were selected by multi-stage stratification and population proportional random sampling method, including 1660 male students and 1561 female students; 420 in large cities, 628 in small and medium-sized cities, 1460 in rural areas, and 713 in poor rural areas. Family members basic information questionnaires were used to collect basic information, measured height, weight to obtain data, after weighted to analyze the height, weight, body mass index(BMI), stunting, wasting, overweight and obesity. RESULTS: In 2010-2013, the development of children and adolescents aged 6-17 in Henan Province were in line with the general principles. The height and weight development of urban students were generally better than those of rural students. The difference between urban and rural areas had been narrowed in BMI. The overall malnutrition rate in the province was 6. 89%. A total of 89 children and adolescents had stunting with a stunting rate of 2. 76%. In addition to stunting, there were 59 moderate-serve wasting(1. 83%) and 74 mild wasting(2. 30%). The malnutrition of rural students was more serious than that of cities. The overweight and obesity rates of children and adolescents in big cities, small and mediumsized cities, ordinary rural areas and poor rural areas were 10. 0%, 9. 69%, 5. 47%, 4. 56%, and 9. 02%, 9. 34%, 3. 40% and 4. 10%, respectively. The overweight and obese were more serious in urban than rural areas. Especially the obesity was epidemic in low-age primary school students. CONCLUSION: In view of the double burden coexists in stunting, wasting, overweight and obesity of children and adolescents in Henan Province, and meanwhile, the feature that malnutrition in rural students more serious, overweight and obese in urban students more critical, scientific and effective preventive measures should be carried out in time to ensure the healthy growth of children and adolescents, especially more attention on lower grade children in primary school.


Assuntos
Estado Nutricional , Sobrepeso , Adolescente , Índice de Massa Corporal , Criança , Cidades , Feminino , Humanos , Masculino , Prevalência , População Rural , População Urbana
17.
Opt Express ; 27(19): 26307-26316, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31674515

RESUMO

We successfully fabricated the long-period fiber gratings in few-mode fibers (FMF-LPFGs) with micro-tapered method, which are different from the traditional LPFGs that only couple the fundamental mode to different cladding modes to obtain multiple resonant dips. There are two resonant dips on the transmission spectrum of the FMF-LPFGs, which are induced by the coupling between the fundamental mode and the low-order cladding mode LP03 (dip 1) and the coupling between the fundamental mode and the high-order core mode LP11 (dip 2). Due to the difference of the coupling mechanism involved in two dips, the shift of resonant wavelengths has different characteristics with the variation of the external environment parameter. The corresponding wavelength of dip 1 exhibits a red shift as the temperature increased. But for dip 2, the resonant wavelength has a blue shift. In addition, the two dips have different temperature and strain sensitivities. Therefore, discriminative determination of temperature and strain is realized by establishing the cross coefficient matrix, and the relative measurement error is less than 3%. What's more, we theoretically analyzed the reason why the two resonant wavelengths shift toward opposite direction with the increase of temperature and toward the same direction with the increase of strain.

18.
Cogn Neurodyn ; 13(6): 601-611, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31741695

RESUMO

Neuron shows distinct dependence of electrical activities on membrane patch temperature, and the mode transition of electrical activity is induced by the patch temperature through modulating the opening and closing rates of ion channels. In this paper, inspired by the physical effect of memristor, the potassium and sodium ion channels embedded in the membrane patch are updated by using memristor-based voltage gate variables, and an external stimulus is applied to detect the variety of mode selection in electrical activities under different patch temperatures. It is found that each ion channel can be regarded as a physical memristor, and the shape of pinched hysteresis loop of memristor is dependent on both input voltage and patch temperature. The pinched hysteresis loops of two ion-channel memristors are dramatically enlarged by increasing patch temperature, and the hysteresis lobe areas are monotonously reduced with the increasing of excitation frequency if the frequency of external stimulus exceeds certain threshold. However, for the memristive potassium channel, the AREA1 corresponding to the threshold frequency is increased with the increasing of patch temperature. The amplitude of conductance for two ion-channel memristors depends on the variation of patch temperature. The results of this paper might provide insights to modulate the neural activities in appropriate temperature condition completely, and involvement of external stimulus enhance the effect of patch temperature.

19.
Oxid Med Cell Longev ; 2019: 6379493, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31583041

RESUMO

As the global population ages, searching for drugs and functional foods which can slow down the aging process has attracted a number of researchers. In this paper, the Lycium barbarum polysaccharides (LBP) extracted from Lycium barbarum was characterized and the effects of LBP on the aging and health of C. elegans were studied. Results showed that LBP can prolong the lifespan, improve the abilities to withstand environmental stress, enhance reproductive potentials, and maintain muscle integrity of C. elegans. By using genetically mutated C. elegans strains, RNAi gene silencing, and measuring the mRNA expression level, it was demonstrated that the lifespan of C. elegans was extended by LBP mainly through sir-2.1, daf-12, and daf-16. The present study might provide a basis for further study of LBP as a food or drug to interfere with aging and reduce the incidence of age-related diseases.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/efeitos dos fármacos , Medicamentos de Ervas Chinesas/efeitos adversos , Medicamentos de Ervas Chinesas/uso terapêutico , Receptores Citoplasmáticos e Nucleares/metabolismo , Envelhecimento , Animais , Medicamentos de Ervas Chinesas/farmacologia
20.
Dalton Trans ; 48(32): 12279-12286, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31342035

RESUMO

Tris- and tetrakis-ß-trifluoromethylated gallium (3CF3-Ga, 4CF3-Ga) and aluminum (3CF3-Al, 4CF3-Al) corrole systems were synthesized by a facile "one-pot" approach from the respective tri- and tetra-iodo starting compounds using the FSO2CF2CO2Me reagent. The isolated 5,10,15-(tris-pentafluorophenyl)corrole-based compounds set the groundwork for another important ß-substituent study in inorganic photocatalysis. As seen previously, -CF3 group substitution leads to red shifts in both the absorption and emission spectra compared to their unsubstituted counterparts (X. Zhan, et al., Inorg. Chem., 2019, 58, 6184-6198). All CF3-substituted corrole complexes showed strong fluorescence; 3CF3-Al possessed the highest fluorescence quantum yield (0.71) among these compounds. The photocatalytic production of bromophenol by way of these photosensitizing complexes was studied demonstrating that tris-trifluoromethylation is an important substitution class, especially when Ga3+ is present (experimental TON value in parentheses): 3CF3-Ga (192) > 4CF3-Ga (146) > 3CF3-Al (130) > 4CF3-Al (56) > 1-Ga (43) > 1-Al (18). The catalytic performance (turn-over number, TON) for benzylbromide formation (from toluene) was found to be: 3CF3-Ga (225) > 1-Ga (138) > 3CF3-Al (130) > 4CF3-Ga (126) > 1-Al (95) > 4CF3-Al (89); in these trials, benzaldehyde was also detected as a product in which 3CF3-Ga outperforms the other compounds (TON = 109). The tetra-CF3-substituted 4CF3-Ga and 4CF3-Al species exhibit a dramatic formal positive shift of 116 mV and 126 mV per [CF3] group, respectively, compared to the unsubstituted parent species 1-Ga and 1-Al. However, the absorbance values (λabs = 400 nm) of these corrole complexes (all equally concentrated: 4.0 × 10-6 M) were 3CF3-Al (0.23) > 3CF3-Ga (0.22) > 1-Al (0.21) > 1-Ga (0.20) > 4CF3-Al (0.19) > 4CF3-Ga (0.15), which helps rationalize why 3CF3-Ga performs the best among these catalysts. These new photosensitizers were carefully characterized by 1H and 19F NMR spectroscopy to help verify the number and position (symmetry) of the CF3 groups; 3CF3-Ga and 3I-Al were structurally characterized. Distortions in the corrole macrocycle imposed by the multiple ß-substitution were quantified.

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