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1.
Sci Rep ; 14(1): 22385, 2024 09 27.
Article in English | MEDLINE | ID: mdl-39333290

ABSTRACT

Dysregulation of the gut microbiome has associated with the occurrence and progression of non-alcoholic fatty liver disease (NAFLD). To determine the diagnostic capacity of this association, we compared fecal microbiomes across 104 participants including non-NAFLD controls and NAFLD subtypes patients that were distinguished by magnetic resonance imaging. We measured their blood biochemical parameters, 16 S rRNA-based gut microbiota and fecal short-chain fatty acids (SCFAs). Multi-omic analyses revealed that NAFLD patients exhibited specific changes in gut microbiota and fecal SCFAs as compared to non-NAFLD subjects. Four bacterial genera (Faecalibacterium, Subdoligranulum, Haemophilus, and Roseburia) and two fecal SCFAs profiles (acetic acid, and butyric acid) were closely related to NAFLD phenotypes and could accurately distinguish NAFLD patients from healthy non-NAFLD subjects. Twelve genera belonging to Faecalibacterium, Subdoligranulum, Haemophilus, Intestinibacter, Agathobacter, Lachnospiraceae_UCG-004, Roseburia, Butyricicoccus, Actinomycetales_unclassified, [Eubacterium]_ventriosum_group, Rothia, and Rhodococcus were effective to distinguish NAFLD subtypes. Of them, combination of five genera can distinguish effectively mild NAFLD from non-NAFLD with an area under curve (AUC) of 0.84. Seven genera distinguish moderate NAFLD with an AUC of 0.83. Eight genera distinguish severe NAFLD with an AUC of 0.90. In our study, butyric acid distinguished mild-NAFLD from non-NAFLD with AUC value of 0.83. And acetic acid distinguished moderate-NAFLD and severe-NAFLD from non-NAFLD with AUC value of 0.84 and 0.70. In summary, our study and further analysis showed that gut microbiota and fecal SCFAs maybe a method with convenient detection advantages and invasive manner that are not only a good prediction model for early warning of NAFLD occurrence, but also have a strong ability to distinguish NAFLD subtypes.


Subject(s)
Fatty Acids, Volatile , Feces , Gastrointestinal Microbiome , Non-alcoholic Fatty Liver Disease , Non-alcoholic Fatty Liver Disease/microbiology , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Humans , Fatty Acids, Volatile/metabolism , Fatty Acids, Volatile/analysis , Male , Female , Middle Aged , Feces/microbiology , Adult , Disease Progression , RNA, Ribosomal, 16S/genetics , Bacteria/classification , Bacteria/isolation & purification , Bacteria/metabolism , Bacteria/genetics
2.
BMC Gastroenterol ; 24(1): 283, 2024 Aug 22.
Article in English | MEDLINE | ID: mdl-39174901

ABSTRACT

BACKGROUND: There is a contradiction in the use of microbiota-therapies, including probiotics, prebiotics, and synbiotics, to improve the condition of patients with nonalcoholic fatty liver disease (NAFLD). The aim of this review was to evaluate the effect of microbiota-therapy on liver injury, inflammation, and lipid levels in individuals with NAFLD. METHODS: Using Pubmed, Embase, Cochrane Library, and Web of Science databases were searched for articles on the use of prebiotic, probiotic, or synbiotic for the treatment of patients with NAFLD up to March 2024. RESULTS: Thirty-four studies involving 12,682 individuals were included. Meta-analysis indicated that probiotic, prebiotic, and synbiotic supplementation significantly improved liver injury (hepatic fibrosis, SMD = -0.31; 95% CI: -0.53, -0.09; aspartate aminotransferase, SMD = -0.35; 95% CI: -0.55, -0.15; alanine aminotransferase, SMD = -0.48; 95% CI: -0.71, -0.25; alkaline phosphatase, SMD = -0.81; 95% CI: -1.55, -0.08), lipid profiles (triglycerides, SMD = -0.22; 95% CI: -0.43, -0.02), and inflammatory factors (high-density lipoprotein, SMD = -0.47; 95% CI: -0.88, -0.06; tumour necrosis factor alpha, SMD = -0.86 95% CI: -1.56, -0.56). CONCLUSION: Overall, supplementation with probiotic, prebiotic, or synbiotic had a positive effect on reducing liver enzymes, lipid profiles, and inflammatory cytokines in patients with NAFLD.


Subject(s)
Non-alcoholic Fatty Liver Disease , Prebiotics , Probiotics , Synbiotics , Humans , Alanine Transaminase/blood , Inflammation , Lipids/blood , Liver , Non-alcoholic Fatty Liver Disease/therapy , Probiotics/therapeutic use , Randomized Controlled Trials as Topic , Synbiotics/administration & dosage
3.
Clin Nutr ; 43(6): 1224-1239, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38643738

ABSTRACT

BACKGROUND: Probiotic administration is a promising therapy for improving conditions in NAFLD patients. This network meta-analysis aimed to compare and estimate the relative effects of probiotic interventions and identify the optimal probiotic species for the treatment of NAFLD (Nonalcoholic fatty liver disease) patients. METHODS: The PubMed, Web of Science, Embase, and Cochrane databases were searched from inception to 29 January 2024 to identify RCTs that were published in English. The GRADE framework was used to assess the quality of evidence contributing to each network estimate. RESULTS: A total of 35 RCTs involving 2212 NAFLD patients were included in the analysis. For primary outcomes, Lactobacillus + Bifidobacterium + Streptococcus exhibited the highest probability of being the finest probiotic combination in terms of enhancing acceptability as well as reducing AST (SMD: -1.95 95% CI: -2.90, -0.99), ALT (SMD = -1.67, 95% CI: -2.48, -0.85), and GGT levels (SMD = -2.17, 95% CI: -3.27, -1.06). In terms of the secondary outcomes, Lactobacillus + Bifidobacterium + Streptococcus was also the best probiotic combination for reducing BMI (SMD = -0.45, 95% CI: -0.86, -0.04), LDL levels (SMD = -0.45, 95% CI: -0.87, -0.02), TC levels (SMD = -1.09, 95% CI: -1.89, -0.29), and TNF-α levels (SMD = -1.73, 95% CI: -2.72, -0.74). CONCLUSION: This network meta-analysis revealed that Lactobacillus + Bifidobacterium + Streptococcus may be the most effective probiotic combination for the treatment of liver enzymes, lipid profiles, and inflammation factors. These findings can be used to guide the development of a probiotics-based treatment guideline for NAFLD since there are few direct comparisons between different therapies.


Subject(s)
Lactobacillus , Network Meta-Analysis , Non-alcoholic Fatty Liver Disease , Probiotics , Probiotics/administration & dosage , Probiotics/therapeutic use , Humans , Non-alcoholic Fatty Liver Disease/therapy , Non-alcoholic Fatty Liver Disease/microbiology , Bifidobacterium , Streptococcus , Treatment Outcome
4.
Psychol Med ; 54(10): 2547-2561, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38497101

ABSTRACT

BACKGROUND: Accumulating data show that probiotics may be beneficial for reducing depressive, anxiety, and stress symptoms. However, the best combinations and species of probiotics have not been identified. The objective of our study was to assess the most effective combinations and components of different probiotics through network meta-analysis. METHOD: A systematic search of four databases, PubMed, Web of Science, Cochrane, and Embase, was conducted from inception to 11 January 2024. The GRADE framework was used to assess the quality of evidence contributing to each network estimate. RESULTS: We deemed 45 trials eligible, these included 4053 participants and 10 types of interventions. The quality of evidence was rated as high or moderate. The NMA revealed that Bifidobacterium exhibited a greater probability of being the optimal probiotic species for improving anxiety symptoms (SMD = -0.80; 95% CI -1.49 to -0.11), followed by Lactobacillus (SMD = -0.49; 95% CI -0.85 to -0.12). In addition, for multiple strains, compared with the other interventions, Lactobacillus + Bifidobacterium (SMD = -0.41; 95% CI -0.73 to -0.10) had a positive effect on depression. CONCLUSION: The NMA revealed that Lactobacillus and Bifidobacterium had prominent efficacy in the treatment of individuals with anxiety, depression, and combination of Lactobacillus + Bifidobacterium had a similar effect. With few direct comparisons available between probiotic species, this NMA may be instrumental in shaping the guidelines for probiotic treatment of psychological disorders.


Subject(s)
Anxiety , Bifidobacterium , Depression , Probiotics , Stress, Psychological , Probiotics/administration & dosage , Probiotics/therapeutic use , Humans , Stress, Psychological/therapy , Anxiety/therapy , Depression/therapy , Lactobacillus , Network Meta-Analysis , Anxiety Disorders/therapy
5.
Obes Rev ; 24(12): e13639, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37732463

ABSTRACT

As the most common internal post-transcriptional RNA modification in eukaryotic cells, N6-methyladenosine (m6 A) performs a dynamic and reversible role in a variety of biological processes mediated by methyltransferases (writers), demethylases (erasers), and m6 A binding proteins (readers). M6 A methylation enables transcriptome conversion in different signals that regulate various physiological activities and organ development. Over the past few years, emerging studies have identified that mRNA m6 A regulators defect in ß-cell leads to abnormal regulation of the target mRNAs, thereby resulting in ß-cell dysfunction and loss of ß-cell identity and mass, which are strongly associated with type 2 diabetes mellitus (T2DM) pathogenesis. Also, mRNA m6 A modification has been implicated with insulin resistance in muscles, fat, and liver cells/tissues. In this review, we elaborate on the biological features of m6 A methylation; provide a comprehensive overview of the underlying mechanisms that how it controls ß-cell function, identity, and mass as well as insulin resistance; highlight its connections to glucose metabolism and lipid metabolism linking to T2DM; and further discuss its role in diabetes complications and its therapeutic potentials for T2DM diagnosis and treatment.


Subject(s)
Diabetes Mellitus, Type 2 , Insulin Resistance , Humans , Methylation , Diabetes Mellitus, Type 2/genetics , Insulin Resistance/genetics , Methyltransferases/genetics , Methyltransferases/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism
6.
Biomed Pharmacother ; 163: 114864, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37167728

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) is gradually becoming one of the most common and health-endangering diseases. Flaxseed powder (FLA) is rich in α-linolenic acid, dietary fiber, lignans, and other active ingredients, which have lipid-lowering and anti-inflammatory effects. Here, we investigated whether the FLA improves host metabolism by gut bacteria modulation and further bile acid modulation in mice fed a high-fat diet. At the end of the experiment, we found that FLA can significantly reduce the body weight, body fat content, and serum TG, LDL-C, and TNF-α levels of mice, and improve liver steatosis. FLA intervention has a significant effect on preventing and regulating the gut flora disturbance caused by HFD. FLA intervention affects bile acid metabolism in the intestine and causes significant changes in functional bile acids, which can play a lipid-lowering and anti-inflammatory role by activating the intestinal Fxr- Fgfr4-Cyp7a1 and Tgr5-Tlr4-Tnfα pathways.


Subject(s)
Flax , Gastrointestinal Microbiome , Non-alcoholic Fatty Liver Disease , Mice , Animals , Non-alcoholic Fatty Liver Disease/metabolism , Bile Acids and Salts/metabolism , Powders/pharmacology , Diet, High-Fat/adverse effects , Metabolic Networks and Pathways , Lipids/pharmacology , Mice, Inbred C57BL , Liver/metabolism
7.
Environ Sci Pollut Res Int ; 30(12): 34728-34740, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36520283

ABSTRACT

Harmful algal blooms is a widespread problem in aquatic ecosystems, in particular dinoflagellates that produce PSTs which are harmful to animal and human health. To explore the contamination status of PSTs in shellfish in the Southeastern China, a total of 2355 shellfish samples were analyzed by ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to study the toxin profiles of the 10 PSTs collected from the southeast coast of China from 2017 to 2021. From 2355 shellfish samples, 257 were detected (10.91%), with the highest value in samples of Perna viridis. Among the six source areas in China, the samples from Fujian recorded the highest detected rate (15.28%). PSTs were found in Fuzhou, Ningde, Quanzhou, Putian, Zhangzhou, and Xiamen, with Quanzhou and Fuzhou having the highest and lowest detection rates of 15.28% and 4.23%, respectively. Saxitoxin (STX), neosaxitoxin (neoSTX), gonyautoxin (GTX1, GTX2, GTX3, GTX4), N-sulfocarbamoyl toxin (GTX5), and decarbamoyl toxin (dcSTX, dcGTX2, dcGTX3) were detected, and GTX5 and dcGTX2 were dominant. In addition, the samples containing PSTs were mostly concentrated in May to August. The study confirms the risks of PSTs to shellfish consumers in the region. It will offer a great foundation for future monitoring of marine toxins and protecting the health of seafood consumers in China. This is the first detailed evaluation of PSTs occurrences and their profiles in shellfish from the Southeastern China over a period of multiple years. HIGHLIGHTS: 2355 mussels from China were analyzed by UPLC-MS/MS for PSTs in 2017-2021. The predominant PSTs were GTX5, neoSTX and dcGTX2. Arca granosa and Crassostyea gigas exhibited higher levels than other shellfish. Shellfish containing PSTs were mostly concentrated in May to August. Maximum detected level in shellfish was 2137.10 ug STXeq/kg.


Subject(s)
Ecosystem , Shellfish Poisoning , Animals , Humans , Chromatography, Liquid/methods , Tandem Mass Spectrometry , Shellfish/analysis , Saxitoxin/analysis , Seafood/analysis , China
8.
Psychiatry Res ; 312: 114560, 2022 06.
Article in English | MEDLINE | ID: mdl-35500333

ABSTRACT

To assess the effect of aerobic exercise (AZ) on global cognition and different cognition domains in patients with schizophrenia (SZ) in daily care. Selection of the literature was done through the Pubmed, Web of Science, Embase and Cochrane Library databases. Standardized mean difference (SMD) and 95% confidence intervals (CIs) were used to assess the effect of AZ on cognition of SZ patients. All assessment indicators were subjected to sensitivity analysis to test the stability of the result. Subgroup analysis was conducted on study type, follow-up time, supervisor and control method. Totally, 23 articles enrolling 1014 participants were included. The global cognition of SZ patients was improved after 6 months of follow-up. AE guided by an occupational therapist improved the global cognition of SZ patients. AE was associated with improved verbal learning and memory, reasoning and problem solving (SMD: 0.375, 95%CI: 0.009 to 0.741, P = 0.045). However, effects on speed of processing, attention/vigilance, work memory, visual learning and memory, social cognition were not significant. The effect of AE training on global cognition may be maintained over the long-term, and be domain specific. Patients with SZ can do AE guided by professional occupational therapist in their daily lives settings.


Subject(s)
Cognition Disorders , Schizophrenia , Attention , Cognition , Cognition Disorders/complications , Exercise , Humans , Schizophrenia/complications , Schizophrenia/therapy
9.
Micromachines (Basel) ; 13(5)2022 May 23.
Article in English | MEDLINE | ID: mdl-35630275

ABSTRACT

The Negative Bias Temperature Instability (NBTI) effect of partially depleted silicon-on-insulator (PDSOI) PMOSFET based on 130 nm is investigated. First, the effect of NBTI on the IV characteristics and parameter degradation of T-Gate PDSOI PMOSFET was investigated by accelerated stress tests. The results show that NBTI leads to a threshold voltage negative shift, saturate drain current reduction and transconductance degradation of the PMOSFET. Next, the relationship between the threshold voltage shift and stress time, gate bias and temperature, and the channel length is investigated, and the NBTI lifetime prediction model is established. The results show that the NBTI lifetime of a 130 nm T-Gate PDSOI PMOSFET is approximately 18.7 years under the stress of VG = -1.2 V and T = 125 °C. Finally, the effect of the floating-body effect on NBTI of PDSOI PMOSFET is investigated. It is found that the NBTI degradation of T-Gate SOI devices is greater than that of the floating-body SOI devices, which indicates that the floating-body effect suppresses the NBTI degradation of SOI devices.

10.
Medicine (Baltimore) ; 100(1): e23876, 2021 Jan 08.
Article in English | MEDLINE | ID: mdl-33429747

ABSTRACT

OBJECTIVES: To assess the effect of aerobic exercise (AE) on cognition function in people with schizophrenia (SZ) during daily nursing. METHODS: The literature search will be conducted via PubMed, Embase, Cochrane Library, and Web of Science. Weighted mean difference (WMD) or standardized mean difference (SMD) and 95% confidence intervals (CIs) will be adopted to calculate the association between AE and cognitive function in patients with SZ. Publication bias will be performed by Begg test. When there is publication bias, "cut-and-fill method" will be adopted to adjust publication bias. Sensitivity analysis will be used to test the stability of the result. When the heterogeneity is large (I2 ≥ 50%), meta regression will be used to explore the source of inter-study heterogeneity. When the heterogeneity is large (I2 ≥ 50%) and the results are statistically significant (P < .05), age, sex, duration of disease, duration of intervention, amount of exercise per week, improvement of cardiopulmonary health, and other factors will be sub-analyzed. CONCLUSION: This meta-analysis will evaluate the impact of aerobic exercise on cognitive function in patients with SZ during daily nursing on the basis of existing evidence. OSF REGISTRATION NUMBER: 10.17605/OSF.IO/C8ABX.


Subject(s)
Clinical Protocols , Cognition/physiology , Exercise/physiology , Schizophrenia/nursing , Correlation of Data , Exercise/psychology , Humans , Meta-Analysis as Topic , Nursing Care/methods , Nursing Care/standards , Systematic Reviews as Topic
11.
Adv Mater ; 32(29): e2000953, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32519397

ABSTRACT

Advanced microscopy and/or spectroscopy tools play indispensable roles in nanoscience and nanotechnology research, as they provide rich information about material processes and properties. However, the interpretation of imaging data heavily relies on the "intuition" of experienced researchers. As a result, many of the deep graphical features obtained through these tools are often unused because of difficulties in processing the data and finding the correlations. Such challenges can be well addressed by deep learning. In this work, the optical characterization of 2D materials is used as a case study, and a neural-network-based algorithm is demonstrated for the material and thickness identification of 2D materials with high prediction accuracy and real-time processing capability. Further analysis shows that the trained network can extract deep graphical features such as contrast, color, edges, shapes, flake sizes, and their distributions, based on which an ensemble approach is developed to predict the most relevant physical properties of 2D materials. Finally, a transfer learning technique is applied to adapt the pretrained network to other optical identification applications. This artificial-intelligence-based material characterization approach is a powerful tool that would speed up the preparation, initial characterization of 2D materials and other nanomaterials, and potentially accelerate new material discoveries.

12.
Phys Rev Lett ; 123(9): 097601, 2019 Aug 30.
Article in English | MEDLINE | ID: mdl-31524450

ABSTRACT

Complex systems, which consist of a large number of interacting constituents, often exhibit universal behavior near a phase transition. A slowdown of certain dynamical observables is one such recurring feature found in a vast array of contexts. This phenomenon, known as critical slowing-down, is well studied mostly in thermodynamic phase transitions. However, it is less understood in highly nonequilibrium settings, where the time it takes to traverse the phase boundary becomes comparable to the timescale of dynamical fluctuations. Using transient optical spectroscopy and femtosecond electron diffraction, we studied a photoinduced transition of a model charge-density-wave (CDW) compound LaTe_{3}. We observed that it takes the longest time to suppress the order parameter at the threshold photoexcitation density, where the CDW transiently vanishes. This finding can be captured by generalizing the time-dependent Landau theory to a system far from equilibrium. The experimental observation and theoretical understanding of dynamical slowing-down may offer insight into other general principles behind nonequilibrium phase transitions in many-body systems.

13.
Soc Cogn Affect Neurosci ; 14(8): 911-918, 2019 08 31.
Article in English | MEDLINE | ID: mdl-31506681

ABSTRACT

Inspired by the roles of serotonin in an emotional aversion to harmful actions, we examined to what extent serotonin transporter gene (5-HTT)-linked polymorphic region (5-HTTLPR), a proxy for measuring serotonin function, underpinned the individual differences in moral judgment through cross-sectional analysis and two-wave comparison. The cross-sectional analysis with a larger cohort (N = 1197) showed that the SS carriers of the 5-HTTLPR polymorphism, corresponding to the low ratio of serotonin recycling from the synaptic cleft, rated impersonal harmful actions (e.g. flipping a switch to divert a train to hit one person instead of five people) as more permissible as compared with the L-allele carriers. The two-wave comparison with a subsample from the larger cohort (N = 563) indicated that the association between 5-HTTLPR polymorphism and moral permissibility of impersonal harmful actions was stable from wave 1 to wave 2. Thus, these findings highlight the importance of the 5-HTTLPR polymorphism to harmful moral behaviors.


Subject(s)
Emotions , Morals , Polymorphism, Genetic , Serotonin Plasma Membrane Transport Proteins/genetics , Adult , Alleles , Cross-Sectional Studies , Female , Genotype , Humans , Judgment , Male , Serotonin
14.
Article in English | MEDLINE | ID: mdl-30707988

ABSTRACT

BACKGROUNDS: Alexithymia refers to the difficulties in identifying and describing one's own emotions, lacking of imagination, and an externally oriented thinking style. Studies up to date have examined the associations of 5-HTTLPR and COMT Val158Met polymorphisms with alexithymia. However, the previous findings were mixed. METHODS: We replicated the associations by scoring on alexithymia with the 20-item Toronto Alexithymia Scale and genotyping the polymorphisms of 5-HTTLPR and COMT Val158Met in a large population of college students (N = 1698). Moreover, we also meta-analyzed the associations with five samples (N = 7517) for the 5-HTTLPR and with five samples (N = 2186) for the COMT Val158Met. RESULTS: Neither the replicated study nor the meta-analyses indicated the 5-HTTLPR and COMT Val158Met were associated with alexithymia. CONCLUSIONS: The findings suggest that the 5-HTTLPR and COMT Val158Met polymorphisms are not associated with alexithymia. However, genetic-environmental studies with different ethnicity and psychopathology should be carried in future.


Subject(s)
Affective Symptoms/genetics , Catechol O-Methyltransferase/genetics , Genetic Predisposition to Disease/genetics , Serotonin Plasma Membrane Transport Proteins/genetics , Female , Genotype , Humans , Male , Polymorphism, Single Nucleotide/genetics , Young Adult
15.
Psychoneuroendocrinology ; 103: 8-13, 2019 05.
Article in English | MEDLINE | ID: mdl-30605805

ABSTRACT

Polymorphisms in the oxytocin receptor (OXTR) gene have been shown to be related to individual differences in social skills that are important for building and maintaining social relationships, such as the capability to efficiently process social information and regulate emotions. However, what remains unclear is the potential roles of OXTR polymorphisms in interpersonal adaptability, namely the ability to cope with the situational demands of interpersonal interactions. In this study, we examined the roles of OXTR rs53576 polymorphism in interpersonal adaptability, empathic perception, and dispositional forgiveness in a cohort of 573 college freshmen. The results indicated that the scores on interpersonal adaptability and dispositional forgiveness, apart from empathic perception, increased as functions of the number of G alleles of OXTR rs53576. Moreover, dispositional forgiveness, but not empathic perception, mediated the association between OXTR rs53576 and interpersonal adaptability. The findings highlight the influences of the OXTR gene on adaptive interpersonal interactions, especially when individuals face changing social situations.


Subject(s)
Forgiveness/genetics , Interpersonal Relations , Receptors, Oxytocin/genetics , Adolescent , China , Emotions/physiology , Empathy/genetics , Female , Gene Frequency , Genotype , Humans , Male , Oxytocin/genetics , Oxytocin/metabolism , Personality/genetics , Polymorphism, Single Nucleotide , Receptors, Oxytocin/metabolism , Social Adjustment , Social Skills , Young Adult
16.
Nano Lett ; 18(8): 5205-5210, 2018 08 08.
Article in English | MEDLINE | ID: mdl-30005161

ABSTRACT

Imaging materials and inner structures with resolution below the diffraction limit has become of fundamental importance in recent years for a wide variety of applications. We report subdiffractive internal structure diagnosis of hexagonal boron nitride by exciting and imaging hyperbolic phonon polaritons. On the basis of their unique propagation properties, we are able to accurately locate defects in the crystal interior with nanometer resolution. The precise location, size, and geometry of the concealed defects are reconstructed by analyzing the polariton wavelength, reflection coefficient, and their dispersion. We have also studied the evolution of polariton reflection, transmission, and scattering as a function of defect size and photon frequency. The nondestructive high-precision polaritonic structure diagnosis technique introduced here can be also applied to other hyperbolic or waveguide systems and may be deployed in the next-generation biomedical imaging, sensing, and fine structure analysis.


Subject(s)
Boron Compounds/chemistry , Nanostructures/chemistry , Phonons , Computer Simulation , Molecular Structure , Particle Size
17.
Adv Mater ; 30(16): e1706358, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29532960

ABSTRACT

Hexagonal boron nitride (hBN) is a natural hyperbolic material that supports both volume-confined hyperbolic polaritons and sidewall-confined hyperbolic surface polaritons (HSPs). In this work, efficient excitation, control, and steering of HSPs are demonstrated in hBN through engineering the geometry and orientation of hBN sidewalls. By combining infrared nanoimaging and numerical simulations, the reflection, transmission, and scattering of HSPs are investigated at the hBN corners with various apex angles. It is also shown that the sidewall-confined nature of HSPs enables a high degree of control over their propagation by designing the geometry of hBN nanostructures.

18.
Conscious Cogn ; 55: 205-213, 2017 10.
Article in English | MEDLINE | ID: mdl-28888137

ABSTRACT

Testosterone and estrogen are involved in self-related behavioral dispositions and experiences of subjective well-being. In this study, we investigated to what extent the aromatase (CYP19A1) gene, which encodes an enzyme in converting testosterone into estrogen, contributes to subjective well-being and in another self-related disposition: independent and interdependent self-construal. In study 1, a meta-analysis showed that the GG genotype of CYP19A1 (a G/A substitution at Val80, rs700518) was associated with higher testosterone and lower estradiol. In study 2, an empirical study of individuals with the GG (n=115), AG (n=286) and AA (n=193) genotypes indicated that individuals with the GG genotype exhibited higher independent self-construal and higher subjective well-being. The association between the GG genotype of CYP19A1 Val80 and subjective well-being was mediated by the independent self-construal. Our findings reinforce the idea that personality traits such as independent self-construal explain the link between genetic variant and subjective well-being.


Subject(s)
Aromatase/physiology , Estradiol/blood , Personal Satisfaction , Personality/physiology , Self Concept , Testosterone/blood , Adult , Aromatase/genetics , Female , Genotype , Humans , Male , Young Adult
19.
Nano Lett ; 17(9): 5285-5290, 2017 09 13.
Article in English | MEDLINE | ID: mdl-28805397

ABSTRACT

We investigated phonon-polaritons in hexagonal boron nitride-a naturally hyperbolic van der Waals material-by means of the scattering-type scanning near-field optical microscopy. Real-space nanoimages we have obtained detail how the polaritons are launched when the light incident on a thin hexagonal boron nitride slab is scattered by various intrinsic and extrinsic inhomogeneities, including sample edges, metallic nanodisks deposited on its top surface, random defects, and surface impurities. The scanned tip of the near-field microscope is itself a polariton launcher whose efficiency proves to be superior to all the other types of polariton launchers we studied. Our work may inform future development of polaritonic nanodevices as well as fundamental studies of collective modes in van der Waals materials.

20.
PLoS One ; 11(9): e0162028, 2016.
Article in English | MEDLINE | ID: mdl-27658309

ABSTRACT

Brain aging is a complex and heterogeneous process characterized by the selective loss and preservation of brain functions. This study examines the normal aging effects on the cerebral cortex by characterizing changes in functional connectivity using resting-state fMRI data. Previous resting-state fMRI studies on normal aging have examined specific networks of the brain, whereas few studies have examined cortical-cortical connectivities across the entire brain. To characterize the effects of normal aging on the cerebral cortex, we proposed the Pearson functional product-moment correlation coefficient for measuring functional connectivity, which has advantages over the traditional correlation coefficient. The distinct patterns of changes in functional connectivity within and among the four cerebral lobes clarified the effects of normal aging on cortical function. Besides, the advantages of the proposed approach over other methods considered were demonstrated through simulation comparisons. The results showed heterogeneous changes in functional connectivity in normal aging. Specifically, the elderly group exhibited enhanced inter-lobe connectivity between the frontal lobe and the other lobes. Inter-lobe connectivity decreased between the temporal and parietal lobes. The results support the frontal aging hypothesis proposed in behavioral and structural MRI studies. In conclusion, functional correlation analysis enables differentiation of changes in functional connectivities and characterizes the heterogeneous aging effects in different cortical regions.

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