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1.
Hum Brain Mapp ; 45(2): e26621, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339823

RESUMO

Recent studies have suggested that emotional reactivity changes with age, but the neural basis is still unclear. The insula may be critical for the emotional reactivity. The current study examined how ageing affects emotional reactivity using the emotional reactivity task data from a human sample (Cambridge Center for Age and Neuroscience, N = 243, age 18-88 years). The resting-state magnetic resonance measurements from the same sample were used to investigate the potential mechanisms of the insula. In the initial analysis, we conducted partial correlation assessments to examine the associations between emotional reactivity and age, as well as between the gray matter volume (GMV) of the insula and age. Our results revealed that emotional reactivity, especially positive emotional reactivity, decreased with age and that the GMV of the insula was negatively correlated with age. Subsequently, the bilateral insula was divided into six subregions to calculate the whole brain resting-state functional connectivity (rsFC). The mediating effect of the rsFC on age and emotional reactivity was then calculated. The results showed that the rsFC of the left anterior insula (AI) with the right hippocampus, and the rsFCs of the right AI with the striatum and the thalamus were mediated the relationship between positive emotional reactivity and age. Our findings suggest that attenuating emotional reactivity with age may be a strategic adaptation fostering emotional stability and diminishing emotional vulnerability. Meanwhile, the findings implicate a key role for the AI in the changes in positive emotional reactivity with age.


Assuntos
Córtex Cerebral , Imageamento por Ressonância Magnética , Humanos , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Córtex Cerebral/diagnóstico por imagem , Encéfalo , Córtex Insular , Lobo Temporal
2.
Ann Vasc Surg ; 98: 235-243, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37392856

RESUMO

BACKGROUND: For patients in whom an upper extremity (UE) vascular access cannot be established, the lower extremity (LE) arteriovenous graft (AVG) could be selected. However, the application of LE AVG is limited owing to its high infection rate, uncertain patency time, and technical difficulties. This study aimed to compare the long-term patency rates and the incidence of vascular access complications of AVG in the LE and UE to provide a reference for the applications of AVG, especially in the LEs. METHODS: This was a retrospective analysis of patients who successfully underwent LE or UE AVG placement from March 2016 to October 2021. Patient characteristics were collected and compared using parameter or nonparameter tests according to data type. Postoperative patency was evaluated using Kaplan-Meier test. Postoperative complication incidence density and intergroup comparison were estimated using the Poisson distribution. RESULTS: Twenty-two patients with LE AVG and 120 patients with UE AVG were included. The 1-year primary patency rate was 67.4% (±11.0% standard error [SE]) in the LE group and 30.1% (±4.5% SE) in the UE group (P = 0.031). The assisted primary patency rate at postoperative months 12, 24, and 36 was respectively 78.6% (±9.6% SE), 65.5% (±14.4% SE), and 49.1% (±17.8% SE) in the LE group and 63.3% (±4.6% SE), 47.5% (±5.4% SE), and 30.4% (±6.1% SE) in the UE group (P = 0.137). The secondary patency rate at postoperative months 12, 24, and 36 remains 95.5% (±4.4% SE) in the LE group and 89.3% (±2.9% SE), 83.7% (±3.9% SE), and 73.0% (±6.2% SE), respectively, in the UE group (P = 0.200). Postoperative complications included stenosis, occlusion/thrombosis, infection, steal syndrome, pseudoaneurysm, severe postoperative serum swelling, and AVG exposure. The total incidence rates of postoperative complications were 0.87 (95% confidence interval [CI] 0.59-1.23) versus 1.61 (95% CI 1.45-1.79) (P = 0.001) cases/person-year, the incidence rates of stenosis were 0.45 (95% CI 0.26-0.73) versus 0.92 (95% CI 0.80-1.06) (P = 0.005) cases/person-year and the incidence rates of occlusion/thrombosis were 0.34 (95% CI 0.17-0.59) versus 0.62 (95% CI 0.52-0.74) cases/person-year in the LE group compared to those in the UE group (P = 0.041). CONCLUSIONS: LE AVG had higher primary patency rate and lower postoperative complication incidence than UE AVG. With the development of interventional technology, both LE AVG and UE AVG exhibited high secondary patency rates. LE AVG can be a reliable and long-term alternative for appropriately selected patients with unusable UE vessels.


Assuntos
Derivação Arteriovenosa Cirúrgica , Implante de Prótese Vascular , Trombose , Humanos , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Oclusão de Enxerto Vascular/etiologia , Oclusão de Enxerto Vascular/complicações , Grau de Desobstrução Vascular , Seguimentos , Diálise Renal/efeitos adversos , Estudos Retrospectivos , Constrição Patológica/cirurgia , Implante de Prótese Vascular/efeitos adversos , Resultado do Tratamento , Extremidade Superior/irrigação sanguínea , Trombose/etiologia
3.
World J Microbiol Biotechnol ; 40(6): 181, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38668833

RESUMO

In view of the extensive potential applications of chitinase (ChiA) in various fields such as agriculture, environmental protection, medicine, and biotechnology, the development of a high-yielding strain capable of producing chitinase with enhanced activity holds significant importance. The objective of this study was to utilize the extracellular chitinase from Bacillus thuringiensis as the target, and Bacillus licheniformis as the expression host to achieve heterologous expression of ChiA with enhanced activity. Initially, through structural analysis and molecular dynamics simulation, we identified key amino acids to improve the enzymatic performance of chitinase, and the specific activity of chitinase mutant D116N/E118N was 48% higher than that of the natural enzyme, with concomitant enhancements in thermostability and pH stability. Subsequently, the expression elements of ChiA(D116N/E118N) were screened and modified in Bacillus licheniformis, resulting in extracellular ChiA activity reached 89.31 U/mL. Further efforts involved the successful knockout of extracellular protease genes aprE, bprA and epr, along with the gene clusters involved in the synthesis of by-products such as bacitracin and lichenin from Bacillus licheniformis. This led to the development of a recombinant strain, DW2△abelA, which exhibited a remarkable improvement in chitinase activity, reaching 145.56 U/mL. To further improve chitinase activity, a chitinase expression frame was integrated into the genome of DW2△abelA, resulting in a significant increas to 180.26 U/mL. Optimization of fermentation conditions and medium components further boosted shake flask enzyme activity shake flask enzyme activity, achieving 200.28 U/mL, while scale-up fermentation experiments yielded an impressive enzyme activity of 338.79 U/mL. Through host genetic modification, expression optimization and fermentation optimization, a high-yielding ChiA strain was successfully constructed, which will provide a solid foundation for the extracellular production of ChiA.


Assuntos
Bacillus licheniformis , Proteínas de Bactérias , Quitinases , Bacillus licheniformis/genética , Bacillus licheniformis/enzimologia , Bacillus thuringiensis/genética , Bacillus thuringiensis/enzimologia , Bacitracina , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Quitinases/biossíntese , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Simulação de Dinâmica Molecular , Família Multigênica , Proteínas Recombinantes/biossíntese , Temperatura
4.
Psychol Med ; 53(8): 3611-3620, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35156595

RESUMO

BACKGROUND: Subthreshold depression could be a significant precursor to and a risk factor for major depression. However, reliable estimates of the prevalence and its contribution to developing major depression under different terminologies depicting subthreshold depression have to be established. METHODS: By searching PubMed and Web of Science using predefined inclusion criteria, we included 1 129 969 individuals from 113 studies conducted. The prevalence estimates were calculated using the random effect model. The incidence risk ratio (IRR) was estimated by measuring the ratio of individuals with subthreshold depression who developed major depression compared to that of non-depressed individuals from 19 studies (88, 882 individuals). RESULTS: No significant difference in the prevalence among the different terminologies depicting subthreshold depression (Q = 1.96, p = 0.5801) was found. By pooling the prevalence estimates of subthreshold depression in 113 studies, we obtained a summary prevalence of 11.02% [95% confidence interval (CI) 9.78-12.33%]. The youth group had the highest prevalence (14.17%, 95% CI 8.82-20.55%), followed by the elderly group (12.95%, 95% CI 11.41-14.58%) and the adult group (8.92%, 95% CI 7.51-10.45%). Further analysis of 19 studies' incidence rates showed individuals with subthreshold depression had an increased risk of developing major depression (IRR = 2.95, 95% CI 2.33-3.73), and the term minor depression showed the highest IRR compared with other terms (IRR = 3.97, 95% CI 3.17-4.96). CONCLUSIONS: Depression could be a spectrum disorder, with subthreshold depression being a significant precursor to and a risk factor for major depression. Proactive management of subthreshold depression could be effective for managing the increasing prevalence of major depression.


Assuntos
Transtorno Depressivo Maior , Adulto , Adolescente , Humanos , Idoso , Transtorno Depressivo Maior/epidemiologia , Depressão/epidemiologia , Prevalência , Fatores de Risco , Razão de Chances
5.
BMC Psychiatry ; 23(1): 626, 2023 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-37641001

RESUMO

OBJECTIVES: Transitions from middle adolescence into merging adulthood, a life stage between age 15-25, has a high prevalence of sleep problems. Mindfulness is a trait defined as being attentive to the present moment which positively relates to sleep quality. In this study, we aimed to investigate how resilience and emotional dysfunction may influence the relationship between trait mindfulness and sleep quality. METHODS: The Five Facet Mindfulness Questionnaire, Connor-Davidson Resilience Scale, Pittsburgh Sleep Quality Index and Depression Anxiety Stress Scales were used to measure the key variables through an online survey of 497 participants between middle adolescence and emerging adults (317 females, mean age 18.27 ± 0.76 years). A process model was built to investigate the mediating roles of resilience and emotional dysfunction in the impact of trait mindfulness on sleep quality, together with the relationships between their specific components. RESULTS: We found a positive association between mindfulness and sleep quality through resilience and through emotional dysfunction, and through the sequential pathway from resilience to emotional dysfunction. Of note, acting with awareness (mindfulness facet) showed significant indirect effects on sleep quality, mediated by resilience and emotional dysfunction. CONCLUSIONS: Our findings may unveil the underlying mechanisms of how low mindfulness induces poor sleep quality. The findings indicate that conceiving mindfulness as a multifaceted construct facilitates comprehension of its components, relationships with other variables, and underscores its potential clinical significance given its critical implications for mental health.


Assuntos
Regulação Emocional , Atenção Plena , Modelos Psicológicos , Resiliência Psicológica , Privação do Sono , Qualidade do Sono , Adolescente , Feminino , Humanos , Masculino , Adulto Jovem , Viés , Compreensão , Saúde Mental , Testes Neuropsicológicos , Psicometria , Reprodutibilidade dos Testes , Resiliência Psicológica/fisiologia , Privação do Sono/fisiopatologia , Privação do Sono/psicologia , Análise de Mediação
6.
Int J Mol Sci ; 24(6)2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36982725

RESUMO

Emerging evidence shows that peripheral systemic inflammation, such as inflammatory bowel disease (IBD), has a close even interaction with central nervous disorders such as Alzheimer's disease (AD). This study is designed to further clarify the relationship between AD and ulcerative colitis (UC, a subclass of IBD). The GEO database was used to download gene expression profiles for AD (GSE5281) and UC (GSE47908). Bioinformatics analysis included GSEA, KEGG pathway, Gene Ontology (GO), WikiPathways, PPI network, and hub gene identification. After screening the shared genes, qRT-PCR, Western blot, and immunofluorescence were used to verify the reliability of the dataset and further confirm the shared genes. GSEA, KEGG, GO, and WikiPathways suggested that PPARG and NOS2 were identified as shared genes and hub genes by cytoHubba in AD and UC and further validated via qRT-PCR and Western blot. Our work identified PPARG and NOS2 are shared genes of AD and UC. They drive macrophages and microglia heterogeneous polarization, which may be potential targets for treating neural dysfunction induced by systemic inflammation and vice versa.


Assuntos
Doença de Alzheimer , Colite Ulcerativa , Doenças Inflamatórias Intestinais , Humanos , Microglia , Colite Ulcerativa/genética , PPAR gama/genética , Doença de Alzheimer/genética , Reprodutibilidade dos Testes , Macrófagos , Inflamação , Biologia Computacional , Óxido Nítrico Sintase Tipo II/genética
7.
Appl Environ Microbiol ; 88(6): e0237421, 2022 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-35108078

RESUMO

Bacillus thuringiensis is a bacterium capable of differentiating into a spore, a dormant and highly resistant cellular form. During the sporulation process, this bacterium produces insecticidal toxins in the form of a crystal inclusion, usually in the sporulating cell. We previously reported that the B. thuringiensis LM1212 strain can differentiate into two distinct subpopulations of sporeformers and crystal producers and that this division-of-labor phenotype provides the bacterium with a fitness advantage in competition with a typical B. thuringiensis strain. The transcription factor CpcR was characterized as the regulator responsible for this phenotype. Here, we examined how CpcR interacts with the sporulation network to control the cell differentiation. We found that the sporulation process was inhibited prior to polar septum formation and that Spo0A activity was impaired in the presence of cpcR in strain LM1212. Using bioinformatics and genetic tools, we identified a gene positively controlled by CpcR encoding a putative phosphatase of the Spo0E family known to specifically dephosphorylate phosphorylated Spo0A (Spo0A-P). We showed that this protein (called Spo0E1) is a negative regulator of sporulation and that variations in spo0E1 expression can modulate the production of spores. Using fluorescent reporters to follow gene expression at the single-cell level, we correlated expression of cpcR and sporulation genes to the formation of the two differentiated subpopulations. IMPORTANCE Formation of spores is a paradigm for study of cell differentiation in prokaryotes. Sporulation initiation is governed by a gradual increase in the level and activity of the master regulator Spo0A. Spo0A is usually indirectly phosphorylated by a multicomponent phosphorelay, and modulation of this phosphorelay system is a critical aspect of Bacillus physiology. Though we know that this phosphorelay system is usually affected by two negative regulatory mechanisms, i.e., rap genes and spo0E family genes, the regulatory mechanisms controlling the transcription of these genes are poorly understood. Here, we report that the transcription factor CpcR positively regulates a spo0E family gene and that variations in spo0E expression can modulate the production of spores in B. thuringiensis. This work emphasizes the diversity in modes of sporulation and illustrates the diversity in the strategies employed by bacteria to control this differentiation pathway and ensure their survival.


Assuntos
Bacillus thuringiensis , Bacillus subtilis/genética , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Diferenciação Celular , Regulação Bacteriana da Expressão Gênica , Esporos Bacterianos/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
8.
Neuroimage ; 238: 118264, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34129948

RESUMO

Humans use different spatial reference frames (allocentric or egocentric) to navigate successfully toward their destination in different spatial scale spaces (environmental or vista). However, it remains unclear how the brain represents different spatial scales and different spatial reference frames. Thus, we conducted an activation likelihood estimation (ALE) meta-analysis of 47 fMRI articles involving human spatial navigation. We found that both the environmental and vista spaces activated the parahippocampal place area (PPA), retrosplenial complex (RSC), and occipital place area in the right hemisphere. The environmental space showed stronger activation than the vista space in the occipital and frontal regions. No brain region exhibited stronger activation for the vista than the environmental space. The allocentric and egocentric reference frames activated the bilateral PPA and right RSC. The allocentric frame showed more stronger activations than the egocentric frame in the right culmen, left middle frontal gyrus, and precuneus. No brain region displayed stronger activation for the egocentric than the allocentric navigation. Our findings suggest that navigation in different spatial scale spaces can evoke specific and common brain regions, and that the brain regions representing spatial reference frames are not absolutely separated.


Assuntos
Rede Nervosa/fisiologia , Lobo Occipital/fisiologia , Giro Para-Hipocampal/fisiologia , Percepção Espacial/fisiologia , Navegação Espacial/fisiologia , Meio Ambiente , Humanos
9.
Mol Microbiol ; 113(4): 740-754, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31793098

RESUMO

Cell differentiation within an isogenic population allows the specialisation of subpopulations and a division of labour. Bacillus thuringiensis is a spore-forming bacterium that produces insecticidal crystal proteins (Cry proteins) in sporulating cells. We recently reported that strain B. thuringiensis LM1212 presents the unique ability to differentiate into two subpopulations during the stationary phase: spore-formers and crystal-producers. Here, we characterised the transcriptional regulator CpcR responsible for this differentiation and the expression of the cry genes. cpcR is located on a plasmid that also harbours cry genes. The alignment of LM1212 cry gene promoters revealed the presence of a conserved DNA sequence upstream from the -35 region. This presumed CpcR box was also found in the promoter of cpcR and we showed that cpcR transcription is positively autoregulated. Electrophoretic mobility shift assays suggested that CpcR directly controls the transcription of its target genes by binding to the CpcR box. We showed that CpcR was able to direct the production of a crystal consisting of a heterologous insecticidal Cry protein in non-sporulating cells of a typical B. thuringiensis kurstaki strain. Moreover, the expression of cpcR induced a reduction in the sporulation of this B. thuringiensis strain, suggesting an interaction between CpcR and the sporulation regulatory networks.


Assuntos
Toxinas de Bacillus thuringiensis/metabolismo , Bacillus thuringiensis , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Sequência Conservada , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Esporos Bacterianos
10.
Depress Anxiety ; 38(8): 860-873, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34254391

RESUMO

BACKGROUND: Trait anxiety is considered a susceptible factor for stress-related disorders, and is characterized by abnormal brain activity and connectivity in the regions related to emotional processing (e.g., the amygdala). However, only a few studies have examined the static and dynamic changes of functional connectivity in trait anxiety. METHOD: We compared the resting-state static and dynamic functional connectivity (sFC/dFC) in individuals with high trait anxiety (HTA, n = 257) and low trait anxiety (LTA, n = 264) using bilateral amygdala subregions as the seeds, that is, the centromedial amygdala (CMA), basolateral amygdala (BLA), and superficial amygdala (SFA). RESULTS: The CMA, BLA, and SFA all showed reduced sFC with the executive control network (ECN) and anomalous dFC with the default mode network (DMN) in individuals with HTA. The CMA only showed reduced sFC with the ECN and reduced dFC with the DMN in individuals with HTA. The BLA showed reduced sFC with the salience network (mainly in the anterior and median cingulate), and increased dFC between the BLA and the DMN in individuals with HTA compared to those with LTA. Notably, HTA showed widespread anomalous functional connectivity in the SFA, including the visual network, mainly in the calcarine fissure, limbic system (olfactory cortex), and basal ganglia (putamen). CONCLUSION: The anomalous sFC and dFC in individuals with HTA may reflect altered mechanisms in prefrontal control, salient stimuli processing, and amygdaloidal responsivity to potential threats, leading to alterations in associative, attentional, interpretative, and regulating processes that sustain a threat-related processing bias in HTA individuals.


Assuntos
Tonsila do Cerebelo , Imageamento por Ressonância Magnética , Tonsila do Cerebelo/diagnóstico por imagem , Ansiedade , Transtornos de Ansiedade , Mapeamento Encefálico , Humanos , Vias Neurais/diagnóstico por imagem
11.
J Am Chem Soc ; 142(7): 3296-3300, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32020802

RESUMO

Novel bolapolyphiles, built of a p-terphenyl or bistolane core with polar glycerol end-groups and two laterally attached n-alkyl or semiperfluoroalkyl chains, form the first "single plumber's nightmare network", the simplest soft-matter cubic phase (Pm3̅m). Its cage-like grid comprises bundles of aromatic rods lying along the cubic unit cell edges, connected by six-way hydrogen-bonded junctions. Side-chains fill the remaining volume of this unique noninterpenetrating liquid-crystalline organic framework.

12.
Sensors (Basel) ; 20(18)2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32899773

RESUMO

Building a human-like car-following model that can accurately simulate drivers' car-following behaviors is helpful to the development of driving assistance systems and autonomous driving. Recent studies have shown the advantages of applying reinforcement learning methods in car-following modeling. However, a problem has remained where it is difficult to manually determine the reward function. This paper proposes a novel car-following model based on generative adversarial imitation learning. The proposed model can learn the strategy from drivers' demonstrations without specifying the reward. Gated recurrent units was incorporated in the actor-critic network to enable the model to use historical information. Drivers' car-following data collected by a test vehicle equipped with a millimeter-wave radar and controller area network acquisition card was used. The participants were divided into two driving styles by K-means with time-headway and time-headway when braking used as input features. Adopting five-fold cross-validation for model evaluation, the results show that the proposed model can reproduce drivers' car-following trajectories and driving styles more accurately than the intelligent driver model and the recurrent neural network-based model, with the lowest average spacing error (19.40%) and speed validation error (5.57%), as well as the lowest Kullback-Leibler divergences of the two indicators used for driving style clustering.


Assuntos
Condução de Veículo , Automóveis , Acidentes de Trânsito , Análise por Conglomerados , Simulação por Computador , Humanos , Comportamento Imitativo
13.
Angew Chem Int Ed Engl ; 59(7): 2725-2729, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31765511

RESUMO

The single gyroid phase as well as the alternating double network gyroid, composed of two alternating single gyroid networks, hold a significant place in ordered nanoscale morphologies for their potential applications as photonic crystals, metamaterials and templates for porous ceramics and metals. Here, we report the first alternating network cubic liquid crystals. They form through self-assembly of X-shaped polyphiles, where glycerol-capped terphenyl rods lie on the gyroid surface while semiperfluorinated and aliphatic side-chains fill their respective separate channel networks. This new self-assembly mode can be considered as a two-color symmetry-broken double gyroid morphology, providing a tailored way to fabricate novel chiral structures with sub-10 nm periodicities using achiral compounds.

14.
Hum Brain Mapp ; 40(12): 3452-3463, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31282606

RESUMO

Aberrant structural (diffusion tensor imaging [DTI]) and resting-state functional magnetic resonance imagining connectivity are core features of bipolar disorder. However, few studies have explored the integrity agreement between structural and functional connectivity (SC-FC) in bipolar disorder. We examine SC connectivity coupling index whether could potentially provide additional clinical predictive value for bipolar disorder spectrum disorders besides the intramodality network measures. By examining the structural (DTI) and resting-state functional network properties, as well as their coupling index, among 57 euthymic bipolar disorder patients (age 13-28 years, 18 females) and 42 age- and gender-matched healthy controls (age 13-28 years, 16 females), we found that compared to controls, bipolar disorder patients showed increased structural rich-club connectivity as well as decreased functional modularity. Importantly, the coupling strength between structural and functional connectome was decreased in patients compared to controls, which emerged as the most powerful feature discriminating the two groups. Our findings suggest that structural-functional coupling strength could serve as a valuable biological trait-like feature for bipolar disorder over and above the intramodality network measures. Such measure can have important clinical implications for early identification of bipolar disorder individuals, and inform strategies for prevention of bipolar disorder onset and relapse.


Assuntos
Transtorno Bipolar/diagnóstico por imagem , Transtorno Bipolar/fisiopatologia , Encéfalo/fisiopatologia , Conectoma/métodos , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Adolescente , Adulto , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Masculino , Adulto Jovem
15.
J Am Chem Soc ; 140(5): 1805-1811, 2018 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-29156881

RESUMO

Honeycomb structure endows graphene with extraordinary properties. But could a honeycomb monolayer superlattice also be generated via self-assembly of colloids or nanoparticles? Here we report the construction of mono- and multilayer molecular films with honeycomb structure that can be regarded as self-assembled artificial graphene (SAAG). We construct fan-shaped molecular building blocks by covalently connecting two kinds of clusters, one polyoxometalate and four polyhedral oligomeric silsesquioxanes. The precise shape control enables these complex molecules to self-assemble into a monolayer 2D honeycomb superlattice that mirrors that of graphene but on the mesoscale. The self-assembly of the SAAG was also reproduced via coarse-grained molecular simulations of a fan-shaped building block. It revealed a hierarchical process and the key role of intermediate states in determining the honeycomb structure. Experimental images also show a diversity of bi- and trilayer stacking modes. The successful creation of SAAG and its stacks opens up prospects for the preparation of novel self-assembled nanomaterials with unique properties.

16.
Soft Matter ; 13(22): 4122-4131, 2017 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-28548148

RESUMO

Using 2D X-ray diffraction and AFM we studied the configuration, in cylindrical confinement, of hexagonal columnar phases that anchor homeotropically, i.e. with the columns normal to the pore wall. A wide range of pore diameters, from 20 nm to 100 µm, were explored by employing anodic alumina membranes and glass capillaries. The compounds used were a small discotic, hexakis(hexyloxy)triphenylene (HAT6), a large discotic hexa-peri-hexabenzocoronene (HBC), and a T-shaped bolaamphiphile, forming a honeycomb-type columnar phase. It was found that in pores up to tens of µm in diameter the columns adopt the "logpile" configuration with parallel columns crossing the pore perpendicular to its axis. Starting with 20 nm pores, with increasing pore diameter up to 5 different configurations are observed, the sequence being the same for all three compounds in spite of their structural diversity. One of the {100} planes of the hexagonal logpile starts from being parallel to the pore axis, then rotates by 90° as the pore size increases, and eventually becomes tilted to the pore axis by (8.5 ± 1)° as the pore widens further. Finally, in glass capillaries of tens of µm and beyond, the columns become axially oriented, parallel to the capillary axis. This latter finding was particularly unexpected as common sense would suggest axial columns to be favoured by planar anchoring, where in fact, it was shown to be hard to achieve. The present findings should help in the design of low-dimensional semiconductor or ionic conductor devices based on oriented columnar phases.

17.
Addict Biol ; 21(3): 667-78, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-25740690

RESUMO

Neuroimaging studies suggested that drug addiction is linked to abnormal brain functional connectivity. However, little is known about the alteration of brain white matter (WM) connectivity in addictive drug users and nearly no study has been performed to examine the alterations of brain WM connectivity in heroin-dependent individuals (HDIs). Diffusion tensor imaging (DTI) offers a comprehensive technique to map the whole brain WM connectivity in vivo. In this study, we acquired DTI datasets from 20 HDIs and 18 healthy controls and constructed their brain WM structural networks using a deterministic fibre tracking approach. Using graph theoretical analysis, we explored the global and nodal topological parameters of brain network for both groups and adopted a network-based statistic (NBS) approach to assess between-group differences in inter-regional WM connections. Statistical analysis indicated the global efficiency and network strength were significantly increased, but the characteristic path length was significantly decreased in the HDIs compared with the controls. We also found that in the HDIs, the nodal efficiency was significantly increased in the left prefrontal cortex, bilateral orbital frontal cortices and left anterior cingulate gyrus. Moreover, the NBS analysis revealed that in the HDIs, the significant increased connections were located in the paralimbic, orbitofrontal, prefrontal and temporal regions. Our results may reflect the disruption of whole brain WM structural networks in the HDIs. Our findings suggest that mapping brain WM structural network may be helpful for better understanding the neuromechanism of heroin addiction.


Assuntos
Giro do Cíngulo/fisiopatologia , Dependência de Heroína/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Substância Branca/fisiopatologia , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Estudos de Casos e Controles , Imagem de Tensor de Difusão , Feminino , Neuroimagem Funcional , Giro do Cíngulo/diagnóstico por imagem , Dependência de Heroína/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Córtex Pré-Frontal/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto Jovem
18.
Water Sci Technol ; 72(12): 2194-200, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26676007

RESUMO

Treated effluent from wastewater treatment plants has become an important source of excess nutrients causing eutrophication in water. In this study, an ecological purification method was used to further treat eutrophic water. A three-season ecological purification scheme which comprised an emergent plant (Eme.), a submerged plant (Sub.) and a novel biological rope (Bio.), was designed for the treated effluent canal of a wastewater treatment plant. The removal parameters determined from the experiment were input into a QUAL2K model to simulate downstream water quality of the treated effluent canal. Respective removal rates of total nitrogen and total phosphorus of the Eme., Sub. and Bio. were 32.48-37.33% and 31.63-39.86% in summer, 14.12-33.61% and 17.74-23.80% in autumn, and 14.13-18.03% and 10.05-12.75% in winter, with 1-day reaction time. Optimal combinations for summer, autumn/spring, and winter are Eme. + Bio., Eme. + Bio. + Sub., and Sub. + Bio., respectively. Simulated load reduction rates of total nitrogen and total phosphorus for the treated effluent canal were 42.64-78.40% and 30.98-78.29%, respectively, year round with 2.5-day reaction time. This study provides an efficient evaluation and design method for ecological purification engineering.


Assuntos
Modelos Teóricos , Desenvolvimento Vegetal , Águas Residuárias/química , Purificação da Água/métodos , Simulação por Computador , Ecologia , Eutrofização , Concentração de Íons de Hidrogênio , Nitrogênio/metabolismo , Oxigênio/análise , Fósforo/análise , Estações do Ano , Temperatura , Purificação da Água/normas , Qualidade da Água
19.
Am J Med Genet B Neuropsychiatr Genet ; 168B(4): 265-73, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25921517

RESUMO

The effects of ZNF804A rs1344706, a prominent susceptibility gene for schizophrenia, on gray matter (GM) structure in unmedicated schizophrenia (SZ) patients are still unknown, although several previous studies investigated the effects in medicated SZ patients and healthy controls (HC). Analyzing cortical thickness, surface area, and GM volume simultaneously may provide a more precise and complete picture of the effects. We genotyped 59 unmedicated first episode SZ patients and 60 healthy controls for the ZNF804A single nucleotide polymorphism (SNP) rs1344706, and examined between-group differences in cortical thickness, surface area, and cortical volume using a full-factorial 2 × 2 analysis of variance (ANOVA). We found the risk allele (T) in ZNF804A rs1344706, compared to the non-risk allele (G), was associated with thinner cortex in the bilateral precuneus, left precentral gyrus, and several other regions, associated with a smaller cortical surface area in the left superior parietal, precuneus cortex and left superior frontal, and associated with a lower cortical volume in the left superior frontal, left precentral, and right precuneus in SZ patients. In contrast, in the controls, the T allele was associated with the increased cortical measurements compared to the G allele in the same regions as those mentioned above. ZNF804A rs1344706 has significant, but different, effects on cortical thickness, surface area, and cortical volume in multiple regions of the brain cortex. Our findings suggest that ZNF804A rs1344706 may aggravate the risk for schizophrenia by exerting its effects on cortical thickness, surface area, and cortical volume in these brain regions.


Assuntos
Córtex Cerebral/patologia , Predisposição Genética para Doença , Fatores de Transcrição Kruppel-Like/genética , Polimorfismo de Nucleotídeo Único/genética , Esquizofrenia/genética , Adulto , Alelos , Estudos de Casos e Controles , Demografia , Feminino , Substância Cinzenta/patologia , Homozigoto , Humanos , Masculino , Tamanho do Órgão , Fatores de Risco
20.
Neuroimage ; 88: 295-307, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24140937

RESUMO

Accumulating evidence from brain structural imaging studies on heroin dependence has supported links between brain morphological alterations and heroin exposure, particularly in gray matter volume or gray matter density. However, the effects of heroin exposure on cortical thickness and the relationship between cortical thickness and heroin addiction are not yet known. In this study, we acquired 3D high-resolution brain structural magnetic resonance imaging (MRI) data from 18 heroin-dependent individuals (HDIs) and 15 healthy controls (HCs). Using FreeSurfer, we detected abnormalities in cortical thickness in the HDIs. Based on a vertex-wise analysis, the HDIs showed significantly decreased cortical thickness in the bilateral superior frontal, left caudal middle frontal, right superior temporal, and right insular regions compared to the HCs but significantly increased cortical thickness in the left superior parietal, bilateral lingual, left temporal pole, right inferior parietal, right lateral occipital, and right cuneus regions. To supplement these results, a subsequent ROI-wise analysis was performed and showed decreased cortical thickness in the left superior frontal sulcus, left precuneus gyrus, left calcarine sulcus, left anterior transverse collateral sulcus, and the right medial occipital-temporal and lingual sulcus. These regions partially overlapped with the areas identified using the vertex-wise analysis. In addition, we found that the thickness in the right superior frontal and right insular regions was negatively correlated with the duration of heroin use. These results provide compelling evidence for cortical abnormality in HDIs and also suggest that the duration of heroin use may be a critical factor associated with the brain alteration.


Assuntos
Córtex Cerebral/patologia , Dependência de Heroína/patologia , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
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