Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 20 de 24
Filtrer
Plus de filtres










Base de données
Gamme d'année
1.
RSC Adv ; 14(30): 21432-21438, 2024 Jul 05.
Article de Anglais | MEDLINE | ID: mdl-38979469

RÉSUMÉ

In the technical route for the synthesis of avanafil, 1-ethyl-(3-dimethylaminopropyl)carbamyldiimide hydrochloride (EDCI) and 1-hydroxybenzotriazole (HOBT) are used as reactive acid-amine binding agents. HOBT contains trace amounts of hydrazine residue, and there is a risk of introducing potentially mutagenic impurities with hydrazide-containing structures. The potentially genotoxic impurities E (Imp-E) and F (Imp-F) of avanafil with altering hydrazide-structure were synthesized by chemical method; subsequently, the impurities were evaluated and classified according to ICH M7 guidelines. Two complementary quantitative structure-activity relationship (QSAR) evaluation systems (Derek and Sarah) based on expert rules and statistics were used to preliminarily predict the genotoxicity of Imp-E and Imp-F, and the prediction result of E was suspected to be positive. In the Ames test of Imp-E and Imp-F, in the dose range of 62.5-1000 µg per plate, with or without the presence of metabolic activation system S9, the number of revertant colonies did not exceed 2 times the number of colonies in the solvent control group and did not show a dose-response relationship, and the test results were negative. Imp-E and Imp-F were determined to be negative for genotoxicity, which could be controlled as class 5 in ICH M7, that is, non mutagenic impurity.

2.
Front Psychiatry ; 15: 1353103, 2024.
Article de Anglais | MEDLINE | ID: mdl-38827448

RÉSUMÉ

Background: Insular subdivisions show distinct patterns of resting state functional connectivity with specific brain regions, each with different functional significance in chronic cigarette smokers. This study aimed to explore the altered dynamic functional connectivity (dFC) of distinct insular subdivisions in smokers. Methods: Resting-state BOLD data of 31 smokers with nicotine dependence and 27 age-matched non-smokers were collected. Three bilateral insular regions of interest (dorsal, ventral, and posterior) were set as seeds for analyses. Sliding windows method was used to acquire the dFC metrics of different insular seeds. Support vector machine based on abnormal insular dFC was applied to classify smokers from non-smokers. Results: We found that smokers showed lower dFC variance between the left ventral anterior insula and both the right superior parietal cortex and the left inferior parietal cortex, as well as greater dFC variance the right ventral anterior insula with the right middle cingulum cortex relative to non-smokers. Moreover, compared to non-smokers, it is found that smokers demonstrated altered dFC variance of the right dorsal insula and the right middle temporal gyrus. Correlation analysis showed the higher dFC between the right dorsal insula and the right middle temporal gyrus was associated with longer years of smoking. The altered insular subdivision dFC can classify smokers from non-smokers with an accuracy of 89.66%, a sensitivity of 96.30% and a specify of 83.87%. Conclusions: Our findings highlighted the abnormal patterns of fluctuating connectivity of insular subdivision circuits in smokers and suggested that these abnormalities may play a significant role in the mechanisms underlying nicotine addiction and could potentially serve as a neural biomarker for addiction treatment.

3.
J Psychiatry Neurosci ; 49(3): E182-E191, 2024.
Article de Anglais | MEDLINE | ID: mdl-38816028

RÉSUMÉ

BACKGROUND: Esketamine is a version of ketamine that has been approved for treatment-resistant depression, but our previous studies showed a link between non-medical use of ketamine and brain structural and functional alterations, including dorsal prefrontal grey matter reduction among chronic ketamine users. In this study, we sought to determine cortical thickness abnormalities following long-term, non-medical use of ketamine. METHODS: We acquired structural brain images for patients with ketamine use disorder and drug-free healthy controls. We used FreeSurfer software to measure cortical thickness for 68 brain regions. We compared cortical thickness between the 2 groups using analysis of covariance with covariates of age, gender, educational level, smoking, drinking, and whole-brain mean cortical thickness. RESULTS: We included images from 95 patients with ketamine use disorder and 169 controls. Compared with healthy controls, patients with ketamine use disorder had widespread decreased cortical thickness, with the most extensive reductions in the frontal (including the dorsolateral prefrontal cortex) and parietal (including the precuneus) lobes. Increased cortical thickness was not observed among ketamine users relative to comparison participants. Estimated total lifetime ketamine consumption was correlated with reductions in the right inferior parietal and the right rostral middle frontal cortical thickness. LIMITATIONS: We conducted a retrospective cross-sectional study, but longitudinal studies are needed to further validate decreased cortical thickness after nonmedical use of ketamine. CONCLUSION: This study provided evidence that, compared with healthy controls, chronic ketamine users have widespread reductions in cortical thickness. Our study underscores the importance of the long-term effects of ketamine on brain structure and serves as a reference for the antidepressant use of ketamine.


Sujet(s)
Cortex cérébral , Kétamine , Imagerie par résonance magnétique , Troubles liés à une substance , Humains , Kétamine/administration et posologie , Mâle , Femelle , Adulte , Troubles liés à une substance/imagerie diagnostique , Troubles liés à une substance/anatomopathologie , Cortex cérébral/imagerie diagnostique , Cortex cérébral/effets des médicaments et des substances chimiques , Cortex cérébral/anatomopathologie , Jeune adulte , Épaisseur corticale du cerveau , Adulte d'âge moyen
4.
Front Mol Biosci ; 11: 1363838, 2024.
Article de Anglais | MEDLINE | ID: mdl-38741719

RÉSUMÉ

Spinal cord injury (SCI) can lead to serious functional disorders, which have serious impacts on patients and society. The current traditional treatments of SCI are not effective the injured spinal cord is difficult to repair and regenerate. In recent years, stem cell transplantation for the treatment of SCI has been a hot research topic. Dental pulp stem cells have strong abilities of self-renewal and multi-directional differentiation, and have been applied for tissue engineering and regenerative medicine. And dental pulp stem cells have certain advantages in neuro-regenetation, bringing new hope to biotherapy for SCI. This article reviews the characteristics of dental pulp stem cells and their research progress in the treatment of SCI.

5.
Materials (Basel) ; 16(19)2023 Sep 28.
Article de Anglais | MEDLINE | ID: mdl-37834589

RÉSUMÉ

In this work, the nearest-neighbor distances and Voronoi cell features of Cu-Ag deposits were analyzed and fitted with Lognormal, Weibull, and Gamma distributions. The nearest-neighbor distance distributions of the samples were compared with those of complete spatially random points, showing spatial inhomogeneity due to the nucleation exclusion effect. The radial distribution function was calculated, showing both influences from the grain size and the nucleation exclusion effect. Voronoi cells were generated based on the shape of the grains. The size, occupancy, and coordination of the Voronoi cells were examined and fitted. The results show that although the Cu-Ag deposits seemed to be governed by the instantaneous nucleation mode, the spatial distribution of the nuclei was more impacted by the nucleation exclusion effect than the Cu-only samples. This behavior is also justified by the grain size distribution generated with Voronoi cell size and occupancy distributions.

6.
EClinicalMedicine ; 60: 102009, 2023 Jun.
Article de Anglais | MEDLINE | ID: mdl-37251625

RÉSUMÉ

Background: China has approximately 300 million current smokers, and smoking cessation services are limited. This study aimed to assess the efficacy of a Cognitive Behavioral Theory-based smoking cessation intervention ('WeChat WeQuit') via the most popular social media platform in China, WeChat. Methods: A parallel, single-blind, two-arm randomised controlled trial was conducted via WeChat between March 19, 2020 and November 16, 2022. Chinese-speaking adult smokers (n = 2000) willing to quit within one month were recruited and randomised in a 1:1 ratio. The intervention group (n = 1005) received the 'WeChat WeQuit' program and the control group (n = 955) received control messages for 14 weeks (2-week prequit and 12-week postquit). Participants were followed up to 26 weeks after the quit date. The primary outcome was self-reported continuous smoking abstinence rate, biochemically validated at 26 weeks. The secondary outcomes were self-reported 7-day and continuous abstinence rates at 6 months. All analyses were by intention to treat. The trial is registered at ClinicalTrials.gov (NCT03169686). Findings: By intention-to-treat analysis, the biochemically verified 26-week continuous abstinence rate was 11.94% in the intervention group and 2.81% in the control group (OR = 4.68, 95% CI: 3.07-7.13, p < 0.0001). The self-reported 7-day abstinence rates ranged from 39.70% at week 1-32.04% at week 26 for the intervention group and 14.17%-11.86% in the control group for weeks 1 and 26, respectively; the self-reported continuous abstinence rates at weeks 1 and 26 ranged from 34.33% to 24.28% and 9.65% to 6.13% in the intervention group and the control group respectively (all p < 0.0001). Participants with low nicotine dependence or previous quit attempts were more likely to successfully quit smoking. Interpretation: The 'WeChat WeQuit' intervention significantly increased smoking abstinence rates at 6 months and should be considered for treatment-seeking smokers in China. Funding: The research is supported by the Natural Science Foundation of Hunan Province (2020JJ4794, YLiao), the K.C. Wong Postdoctoral Fellowship for YLiao to study at King's College London, and China Medical Board (CMB) Open Competition Program (grant no. 15-226, 22-485, YLiao).

7.
J Hazard Mater ; 447: 130768, 2023 04 05.
Article de Anglais | MEDLINE | ID: mdl-36640508

RÉSUMÉ

Although the effect of Cu2+ on antibiotic removal during photocatalytic reaction has been studied in depth, there is less known about the effect of antibiotics on Cu2+ removal. In this study, we report for the first time that, during the photocatalytic purification of sulfamerazine (SMZ) and Cu2+ combined pollution, Cu2+ concentration showed an obvious five-stage fluctuation, which was completely different from the simple promotion or inhibition reported in previous studies. By employing HPLC-MS analysis and density functional theory (DFT) calculation, the repeated fluctuation of Cu2+ concentration was found to be closely related to the SMZ degradation process, mainly resulting from solution pH drop and formation of Cu-containing intermediates which acted as sacrificial agents for Cu2+ reduction. In addition, compared with the SMZ-free system, the presence of SMZ can greatly enhance the deep removal of Cu2+ (minimum Cu2+ concentration was only 0.17 mg/L vs. 1.28 mg/L without SMZ), and there was a wide time interval to ensure the efficient recovery of Cu metal. More interestingly, the in-situ obtained Cu-decorated TiO2 photocatalyst performed well in water splitting, nitrogen fixation and bacterial sterilization. Results of this study confirmed the great potential of photocatalytic technology in purifying antibiotic-heavy metal combined pollution.


Sujet(s)
Métaux lourds , Sulfamérazine , Antibactériens , Pollution de l'environnement
8.
Environ Sci Pollut Res Int ; 30(12): 33229-33242, 2023 Mar.
Article de Anglais | MEDLINE | ID: mdl-36478555

RÉSUMÉ

The efficient adsorption of radioactive elements from nuclear wastewater is an important research topic in the environmental field. The unique three-dimensional porous structure of aerogels has great potential in the field of adsorption. Phosphoric-modified aloe vera/chitosan aerogel (CS/AL-AP) was prepared from chitosan, phosphoric acid, and aloe powder by vacuum freeze-drying self-assembly. The maximum adsorption of uranyl ions by CS/AL-AP was found to be 322.34 mg/g at pH 6, adsorption time of 120 min, solid-to-liquid ratio of 0.125 g/L, reaction temperature of 303 K, and initial uranyl ion concentration of 50 mg/L. The adsorption process is consistent with the Langmuir isotherm model and the quasi-secondary kinetic model, indicating that the adsorption process is monolayer adsorption. The type of adsorption is mainly chemisorption. FTIR and XPS analyses indicate that the adsorption of U(VI) by CS/AL-AP results from the combined action of coordination or chelation of amino, hydroxyl, and carboxyl groups. In addition, CS/AL-AP shows excellent adsorption capacity in the presence of complex co-existing ions. After five adsorption-desorption experiments, the adsorption capacity of CS/AL-AP for uranyl ions remained at a high level. It indicates that CS/AL-AP has good stability and recoverability. The results indicate that CS/AL-AP has excellent potential in the field of uranium removal.


Sujet(s)
Aloe , Chitosane , Chitosane/composition chimique , Adsorption , Température , Phosphore , Ions , Cinétique , Concentration en ions d'hydrogène
9.
Mindfulness (N Y) ; 13(12): 3123-3133, 2022.
Article de Anglais | MEDLINE | ID: mdl-36408118

RÉSUMÉ

Objectives: Avoiding touching the eyes, nose, and mouth (T-zone) is a strategy to reduce the spread of COVID-19. This study evaluated the effectiveness of a brief mindfulness-based intervention (MBI) named "STOP (Stop, Take a Breath, Observe, Proceed) touching your face" for reducing face-touching behavior. Methods: In this online-based, two-arm, wait-list, randomized controlled trial, eligible participants were randomly assigned to the intervention (n = 545) or control group (n = 545). The results of 60-min self-monitoring of face-touching behavior were reported before and after the intervention. Reduction of the percentage of T-zone touching was the primary outcome, and reduction of face-touching frequency was a key secondary outcome. Outcomes were analyzed on an intention-to-treat (ITT) basis with a complete case analysis (CCA). Results: ITT analysis revealed that the percentage of T-zone touching was significantly reduced by 8.1% in the intervention group (from 81.1 to 73.0%, RR = 0.901, OR = 0.631, RD = - 0.081, p = 0.002), and insignificantly reduced by 0.6% in the control group (from 80.0 to 79.4%, p = 0.821). Fewer participants performed T-zone touching in the intervention group than in the control group (73.0% vs. 79.4%, RR = 0.919, OR = 0.700, RD = - 0.064, p = 0.015) after the intervention, and there was a greater reduction of T-zone touching frequency in the intervention group than in the control group [mean ± SD: 1.7 ± 5.13 vs. 0.7 ± 3.98, mean difference (95% CI): 1.03 (0.48 to 1.58), p < 0.001, Cohen's d = - 0.218]. The above results were further confirmed by CCA. Conclusions: This brief mindfulness-based intervention was potentially effective at reducing the spread of COVID-19 and could be further investigated as an intervention for preventing other infectious diseases spread by hand-to-face touching. Trial Registration: ClinicalTrials.gov NCT04330352. Supplementary Information: The online version contains supplementary material available at 10.1007/s12671-022-02019-x.

10.
Front Cell Neurosci ; 16: 958437, 2022.
Article de Anglais | MEDLINE | ID: mdl-36238830

RÉSUMÉ

Addiction to methamphetamine (MA) is a major public health concern. Developing a predictive model that can classify and characterize the brain-based biomarkers predicting MA addicts may directly lead to improved treatment outcomes. In the current study, we applied the support vector machine (SVM)-based classification method to resting-state functional magnetic resonance imaging (rs-fMRI) data obtained from individuals with methamphetamine use disorder (MUD) and healthy controls (HCs) to identify brain-based features predictive of MUD. Brain connectivity analyses were conducted for 36 individuals with MUD as well as 37 HCs based on the brainnetome atlas, and the neighborhood component analysis was applied for feature selection. Eighteen most relevant features were screened out and fed into the SVM to classify the data. The classifier was able to differentiate individuals with MUD from HCs with a high prediction accuracy, sensitivity, specificity, and AUC of 88.00, 86.84, 89.19, and 0.94, respectively. The top six discriminative features associated with changes in the functional activity of key nodes in the default mode network (DMN), all the remaining discriminative features are related to the thalamic connections within the cortico-striato-thalamo-cortical (CSTC) loop. In addition, the functional connectivity (FC) between the bilateral inferior parietal lobule (IPL) and right cingulate gyrus (CG) was significantly correlated with the duration of methamphetamine use. The results of this study not only indicated that MUD-related FC alterations were predictive of group membership, but also suggested that machine learning techniques could be used for the identification of MUD-related imaging biomarkers.

11.
RSC Adv ; 12(15): 9256-9262, 2022 Mar 21.
Article de Anglais | MEDLINE | ID: mdl-35424898

RÉSUMÉ

Avanafil is a phosphodiesterase type 5 inhibitor which is used to treat erectile dysfunction in men. The process-related impurities of avanafil were investigated, and four kinds of impurities in several laboratory batches with a content of 0.29-1.63% were detected by the newly developed gradient ultra-high performance liquid chromatography (UPLC). Based on the synthesis route and UPLC-MS research, the impurities are inferred as Imp-A, Imp-B, Imp-C and Imp-D. The structures of the impurities were inferred from LC-MS studies and confirmed by synthesis, followed by spectroscopic characterization such as NMR and mass spectrometry. Especially, the synthesis of Imp-D is firstly reported. The drug-related substances can be separated well by efficient and selective ultra-high performance liquid chromatography on a Waters ACQUITY HSS C18 (50 × 2.1 mm, particle size 1.8 µm) column at 35 °C, with the mobile phase consisting of ammonium formate (20 mM) and acetonitrile, and the detection at 239 nm with a DAD detector. The method was validated in terms of specificity, linearity, precision, accuracy and sensitivity, and satisfactory results were obtained. The results indicated this developed UPLC method for avanafil and the proposed synthesis mechanism can be used for quality control purposes as required by regulatory agencies to ensure the safety and efficacy of the product.

12.
Front Neuroinform ; 16: 761942, 2022.
Article de Anglais | MEDLINE | ID: mdl-35273487

RÉSUMÉ

An increasing number of resting-state functional magnetic resonance neuroimaging (R-fMRI) studies have used functional connections as discriminative features for machine learning to identify patients with brain diseases. However, it remains unclear which functional connections could serve as highly discriminative features to realize the classification of autism spectrum disorder (ASD). The aim of this study was to find ASD-related functional connectivity patterns and examine whether these patterns had the potential to provide neuroimaging-based information to clinically assist with the diagnosis of ASD by means of machine learning. We investigated the whole-brain interregional functional connections derived from R-fMRI. Data were acquired from 48 boys with ASD and 50 typically developing age-matched controls at NYU Langone Medical Center from the publicly available Autism Brain Imaging Data Exchange I (ABIDE I) dataset; the ASD-related functional connections identified by the Boruta algorithm were used as the features of support vector machine (SVM) to distinguish patients with ASD from typically developing controls (TDC); a permutation test was performed to assess the classification performance. Approximately, 92.9% of participants were correctly classified by a combined SVM and leave-one-out cross-validation (LOOCV) approach, wherein 95.8% of patients with ASD were correctly identified. The default mode network (DMN) exhibited a relatively high network degree and discriminative power. Eight important brain regions showed a high discriminative power, including the posterior cingulate cortex (PCC) and the ventrolateral prefrontal cortex (vlPFC). Significant correlations were found between the classification scores of several functional connections and ASD symptoms (p < 0.05). This study highlights the important role of DMN in ASD identification. Interregional functional connections might provide useful information for the clinical diagnosis of ASD.

13.
J Affect Disord ; 299: 504-512, 2022 02 15.
Article de Anglais | MEDLINE | ID: mdl-34953921

RÉSUMÉ

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by difficulties with social communication and restricted or repetitive patterns of behavior. This disorder was characterized by widespread abnormalities involving distributed brain networks. As one such key network node, the insular cortex has been regarded as a research focus of ASD neuropathology. The insula is a functionally complex brain structure. However, it is not fully clear if dynamic characteristics of resting-state functional magnetic resonance imaging (R-fMRI) signals in insular heterogeneous could be used to depict abnormalities in ASD. To address this question, we investigated dynamic functional connectivity (dFC) of 12 insular subregions. Data were obtained from 44 individuals with ASD and 65 typically developing age-matched controls (TDC). We assessed dFC by sliding-window method and quantified its temporal variability. Multivariable linear regression models were constructed to determine whether dFC support complementary information about symptom severity of individuals with ASD rather than static functional connectivity (sFC). The results showed that individuals with ASD exhibited dFC and sFC alterations in distinct insular subregions. Some brain regions showed only abnormal dFC but not sFC with insular subregions. These abnormal dFC could significantly predict the symptom severity of individuals with ASD. Our findings might advance our knowledge about the potential of insular heterogeneity and dynamic characteristics in understanding the neuropathology mechanism of ASD and in developing neuroimaging biomarkers for clinical applications.


Sujet(s)
Trouble du spectre autistique , Trouble du spectre autistique/imagerie diagnostique , Encéphale , Cartographie cérébrale , Humains , Cortex insulaire , Imagerie par résonance magnétique , Mâle , Voies nerveuses/imagerie diagnostique
14.
Psychoradiology ; 2(4): 180-189, 2022 Dec.
Article de Anglais | MEDLINE | ID: mdl-38665277

RÉSUMÉ

Drug addiction or substance use disorder (SUD), has been conceptualized as a three-stage (i.e. binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation/craving) recurring cycle that involves complex changes in neuroplasticity, reward, motivation, desire, stress, memory, and cognitive control, and other related brain regions and brain circuits. Neuroimaging approaches, including magnetic resonance imaging, have been key to mapping neurobiological changes correlated to complex brain regions of SUD. In this review, we highlight the neurobiological mechanisms of these three stages of addiction. The abnormal activity of the ventral tegmental, nucleus accumbens, and caudate nucleus in the binge/intoxication stage involve the reward circuit of the midbrain limbic system. The changes in the orbitofrontal cortex, dorsolateral prefrontal cortex, amygdala, and hypothalamus emotional system in the withdrawal/negative affect stage involve increases in negative emotional states, dysphoric-like effects, and stress-like responses. The dysregulation of the insula and prefrontal lobes is associated with craving in the anticipation stage. Then, we review the present treatments of SUD based on these neuroimaging findings. Finally, we conclude that SUD is a chronically relapsing disorder with complex neurobiological mechanisms and multimodal stages, of which the craving stage with high relapse rate may be the key element in treatment efficacy of SUD. Precise interventions targeting different stages of SUD and characteristics of individuals might serve as a potential therapeutic strategy for SUD.

15.
ACS Omega ; 6(42): 28004-28011, 2021 Oct 26.
Article de Anglais | MEDLINE | ID: mdl-34723000

RÉSUMÉ

Two polymers (polyBAUEE and polyBAUP) containing 25- and 20-membered rings are synthesized by the cyclopolymerization of bifunctional monomers 1,2-bis(acryloyloxyethyl-ureidoethoxyl)-ethane (BAUEE) and 1,3-bis(acryloyloxyethylureido)propane (BAUP) and studied for the adsorption of precious metal ions. PolyBAUEE and polyBAUP selectively adsorb Au(III) with the adsorption efficiencies above 99.0% after adsorption equilibrium. PolyBAUEE adsorbed faster than polyBAUP, and the Au(III) adsorption is selective in the presence of nine interfering metal ions with similar concentrations (ca. 1 mg/L) in an aqueous solution including Pd(II) and Pt(II). The maximum Au(III) adsorption capacities of polyBAUEE and polyBAUP are 37.6 and 31.8 mg/g, respectively. Au(III) is reduced to Au(0) nanoparticles during the adsorption process. The selective adsorption behavior depends on the controlling regioselective recognition of the ring structure and the ureido groups.

16.
Psychiatry Investig ; 18(8): 763-769, 2021 Aug.
Article de Anglais | MEDLINE | ID: mdl-34380296

RÉSUMÉ

OBJECTIVE: The connectivity alterations in the putamen were found in revealing the neural correlates of attention-deficit/hyperactivity disorder (ADHD), but whether the effective connectivity of the putamen is atypical in ADHD remains unclear. Investigating this abnormality contributes to describing the neural circuit of ADHD at the level of macrostructural organization. METHODS: Data were acquired from thirty-two boys with ADHD and fifty-two matched typically developing controls (TDC) from Peking University (Peking) dataset deposited at the Neuroimaging Informatics Tools and Resources Clearinghouse (NITRC) platform. We examined the effective connectivity of the putamen using Granger causality analysis (GCA) and then determined whether these connections could differentiate ADHD from TDC. RESULTS: Compared with TDC, the ADHD group showed decreased effective connectivity from the left ventral rostral putamen (VRP) to left calcarine (CAL), right medial part of the superior frontal gyrus, left orbital part of superior frontal gyrus and left middle occipital gyrus (MOG). Increased effective connectivity from the left inferior occipital gyrus and right lingual gyrus to left VRP was also found in ADHD. The result of the classification accuracy showed that 72.3% of participants were correctly classified using support vector machine. Moreover, GCA values from the left VRP to left CAL and left MOG were significantly correlated with hyper/impulsive scores of patients with ADHD. CONCLUSION: The findings may help extend our understanding of the ADHD-related neural loops.

17.
J Psychiatr Res ; 138: 569-575, 2021 06.
Article de Anglais | MEDLINE | ID: mdl-33991995

RÉSUMÉ

Attention-deficit/hyperactivity disorder (ADHD) patients have presented aberrant static brain networks, however identifying ADHD patients based on dynamic information in brain networks is not fully clear. Data were obtained from 32 boys with ADHD and 52 sex- and age-matched typically developing controls; a sliding-window method was used to assess dynamic functional connectivity (dFC), and two reoccurring dFC states (the hot and cool states) were then identified using a k-means clustering method. The results showed that ADHD patients had significant changes in occurrence, transitions times and dFC strength of the cingulo-opercular network (CON) and sensorimotor network (SMN) in the cool state. The severity of ADHD symptoms showed significant correlations with the regional amplitude of dFC fluctuations in the ventral medial prefrontal cortex (vmPFC), anterior medial prefrontal cortex (amPFC) and precuneus. These findings could provide insights on the state-dependent dynamic changes in large-scale brain connectivity and network configurations in ADHD.


Sujet(s)
Trouble déficitaire de l'attention avec hyperactivité , Encéphale/imagerie diagnostique , Cartographie cérébrale , Humains , Imagerie par résonance magnétique , Mâle , Réseau nerveux/imagerie diagnostique , Voies nerveuses/imagerie diagnostique
18.
Neuroimage ; 233: 117966, 2021 06.
Article de Anglais | MEDLINE | ID: mdl-33744460

RÉSUMÉ

Volitional eye closure is observed only in conscious and awake humans, and is rare in animals. It is believed that eye closure can focus one's attention inward and facilitate activities such as meditation and mental imagery. Congenital blind individuals are also required to close their eyes for these activities. Resting-state functional magnetic resonance imaging (RS-fMRI) studies have found robust differences between the eyes-closed (EC) and eyes-open (EO) conditions in some brain regions in the sighted. This study analyzed data from 21 congenital blind individuals and 21 sighted controls by using amplitude of low-frequency fluctuation (ALFF) of RS-fMRI. The blind group and the sighted group shared similar pattern of differences between the EC and EO condition: ALFF was higher in the EC condition than the EO condition in the bilateral primary sensorimotor cortex, bilateral supplementary motor area, and inferior occipital cortex, while ALFF was lower in the EC condition than the EO condition in the medial prefrontal cortex, highlighting the "nature" effect on the difference between the EC and EO conditions. The results of other matrices such as fractional ALFF (fALFF) and regional homogeneity (ReHo) showed similar patterns to that of ALFF. Moreover, no significant difference was observed between the EC-EO pattern of the two subgroups of congenital blind (i.e., with and without light perception), suggesting that the EC-EO difference is irrespective of residual light perception which reinforced the "nature" effect. We also found between-group differences, i.e., more probably "nurture effect", in the posterior insula and fusiform. Our results suggest that the acts of closing and opening the eyes are of importance for the congenital blind, and that these actions and their differences might be inherent in the nature of humans.


Sujet(s)
Cécité/imagerie diagnostique , Encéphale/imagerie diagnostique , Oeil/imagerie diagnostique , Imagerie par résonance magnétique/méthodes , Réseau nerveux/imagerie diagnostique , Repos , Adolescent , Adulte , Cécité/physiopathologie , Encéphale/physiopathologie , Oeil/physiopathologie , Paupières/imagerie diagnostique , Paupières/physiopathologie , Femelle , Glaucome/imagerie diagnostique , Glaucome/physiopathologie , Humains , Mâle , Réseau nerveux/physiopathologie , Repos/physiologie , Rétinopathies/imagerie diagnostique , Rétinopathies/physiopathologie , Jeune adulte
19.
Inorg Chem ; 59(8): 5405-5417, 2020 Apr 20.
Article de Anglais | MEDLINE | ID: mdl-32239924

RÉSUMÉ

Some alloys are very difficult to electrodeposit, due to problems such as the large difference in the equilibrium potentials and/or deposition kinetics of the alloy components, as well as the bath instability due to the spontaneous reactions in the bulk electrolyte. The Ag-Fe system is one of those. In this work, a novel alkaline citrate-dimethylhydantoin (DMH) complex has been used to synthesize thermodynamically immiscible Ag-Fe alloy films. The large difference in standard potentials and deposition kinetics of Ag and Fe is partially resolved by complexing Ag(I) with DMH, while the instability caused from spontaneous reduction of Ag(I) by Fe(II) was partially resolved by adding 1% Fe3+, based on the philosophy of the mixed potential theory. Furthermore, a paradigm for control of film composition is developed, based on the mass-transfer coefficient ratio, tested with various bath constitutions. Uniform and high-quality films are obtained, with a composition error of <4 at. % comparing with the predicted values. Electrochemical reactions involved in the deposition baths were systematically investigated using cyclic voltammetry, showing satisfactory agreement with the predicted deposition potentials calculated by equilibrium thermodynamics. The films deposited at high overpotential are proven to be biphasic, containing Ag-fcc and Fe-bcc phases, with a trend of decreasing crystallinity at increasing overpotentials when deposited at constant deposition time. A narrow transition potential range (<0.05 V) from the onset of Fe deposition to its limiting current condition was observed.

20.
Neuropsychiatr Dis Treat ; 16: 691-702, 2020.
Article de Anglais | MEDLINE | ID: mdl-32210565

RÉSUMÉ

PURPOSE: In recent years, machine learning techniques have received increasing attention as a promising approach to differentiating patients from healthy subjects. Therefore, some resting-state functional magnetic resonance neuroimaging (R-fMRI) studies have used interregional functional connections as discriminative features. The aim of this study was to investigate ADHD-related spatially distributed discriminative features derived from whole-brain resting-state functional connectivity patterns using machine learning. PATIENTS AND METHODS: We measured the interregional functional connections of the R-fMRI data from 40 ADHD patients and 28 matched typically developing controls. Machine learning was used to discriminate ADHD patients from controls. Classification performance was assessed by permutation tests. RESULTS: The results from the model with the highest classification accuracy showed that 85.3% of participants were correctly identified using leave-one-out cross-validation (LOOV) with support vector machine (SVM). The majority of the most discriminative functional connections were located within or between the cerebellum, default mode network (DMN) and frontoparietal regions. Approximately half of the most discriminative connections were associated with the cerebellum. The cerebellum, right superior orbitofrontal cortex, left olfactory cortex, left gyrus rectus, right superior temporal pole, right calcarine gyrus and bilateral inferior occipital cortex showed the highest discriminative power in classification. Regarding the brain-behaviour relationships, some functional connections between the cerebellum and DMN regions were significantly correlated with behavioural symptoms in ADHD (P < 0.05). CONCLUSION: This study indicated that whole-brain resting-state functional connections might provide potential neuroimaging-based information for clinically assisting the diagnosis of ADHD.

SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE
...