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1.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 28(1): 51-55, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32027252

RESUMO

OBJECTIVE: To investigate the effects of IRF1 on the homeostasis and differentiation of K562 cells. METHODS: Three different vectors were constructed to screen the best strategy for IRF1 overexpression. The effect of IRF1 on cell proliferation and apoptosis was explored by cell count and apoptotic surface marker detection. Likely, the effect of IRF1 on cell differentiation was analyzed by differentiational surface marker assay. Finally, the regulation mechanism at mRNA level was analyzed by RT-qPCR. RESULTS: The single open reading frame constructed by P2A-T2A element showed the highest expression intensity, and it was the best approach to realize IRF1 enhancement. Cell counts showed that IRF1 had no significant effect on the proliferation of K562. Annexin V and 7-AAD labeling exhibited strong anti-apoptotic function of IRF1 against AraC induction. Flow cytometry revealed that IRF1 overexpression could also further increase the proportion of CD71+CD235a+ cells. RT-qPCR confirmed its upregulation effect on CD235a and TAL1. CONCLUSION: IRF1 enhancement alters the homeostasis characteristics of K562 cells, increases the anti-apoptotic ability and raises the potential to downstream differentiation, suggesting that IRF1 may play an important regulatory role in the hematopoietic development, including erythropoiesis.


Assuntos
Apoptose , Homeostase , Proliferação de Células , Humanos , Fator Regulador 1 de Interferon , Interferons , Células K562
2.
Biochem Biophys Res Commun ; 521(2): 326-332, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31668371

RESUMO

Hematopoiesis is systematically regulated by microenvironmental factors. The positive and negative factors coordinated together to yield a complicated blood system. Interferon-γ (IFNγ) has been identified as a common cause of various hematopoietic abnormalities, such as aplastic anemia. However, its impact on monolineage development, especially erythropoiesis, has not been fully elucidated from the cellular angle. In this study, we investigated the behavior of IFNγ and found that IFNγ plays dual functions on erythropoiesis; it not only blocks the erythroid lineage commitment but also accelerates the erythroid differentiation process, ultimately leading to the erythropoietic window clearance. IFNγ can even powerfully initiate early differentiation without the existence of erythropoietin (EPO). Interferon regulatory factor 1 (IRF1) was confirmed as the essential downstream effector, and its ectopic overexpression can also have the same effect as that of IFNγ. These results reveal that the IFNγ-IRF1 axis plays a bidirectional role on erythropoiesis, impeding the access to erythroid lineage and driving the coming cells toward the differentiation endpoint. This model may place an innovative implication for IFNγ-IRF1 axis to understand its in-depth mechanism on normal hematopoiesis and abnormal blood disorders, especially aplastic anemia.

3.
J Cosmet Dermatol ; 19(1): 47-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31479196

RESUMO

BACKGROUND: Melasma is a benign and chronic hypermelanosis characterized by irregular light brown to dark brown patches of hyperpigmentation on the skin. Oral tranexamic acid (TA) or vitamin C (VC) supplementation has been one treatment choice. TA interferes with keratinocyte-melanocyte interactions, and VC functions by reducing melanin production resulting in skin rejuvenation and whitening. AIM: The aim of the present study was to compare the efficacy and safety of Myjet assisted transdermal injection of TA vs VC in the treatment of melasma. METHODS: In this split-face controlled trial, 17 patients were randomized to receive eight weekly transdermal injections of TA or VC via Myjet either on the right or the left side of their face. MASI was measured from each side of the face at the baseline, at the middle, and at the end of treatment. RESULTS: A reduction in MASI was observed for TA and VC separately (P value < 0.05). The difference in efficacy between TA and VC group was not statistically significant (P value 0.05). Both treatments were well tolerated, with no serious adverse events reported. CONCLUSION: Weekly TA or VC transdermal injections can be an effective treatment for melasma. Further studies are required to validate these findings.

4.
J Nanosci Nanotechnol ; 20(5): 3225-3230, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31635668

RESUMO

Surface properties and structures of materials are essential for their adsorption of pollutants in water. Humic acids (HA)-supported CeO2 nanosheet composites are synthesised by solvothermal method. The size of CeO2 nanosheets are approximately 100-500 nm. The obtained composite exhibits superior adsorption ability for Congo Red (CR) in water, which can be attributed to its unique structure and highly dispersed CeO2 nanosheet. The composite's adsorption behaviour of CR follows a pseudo-second-order mode and Langmuir adsorption model well, and the maximum adsorptive capacity for CR achieves 260 mg g-1. The presence of CeO2 nanosheets enhances surface area and enriches the mesoporous structure of the composites, thereby promoting CR adsorption capacity.

5.
Nat Commun ; 10(1): 5589, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811122

RESUMO

Excitons in two-dimensional (2D) materials are tightly bound and exhibit rich physics. So far, the optical excitations in 2D semiconductors are dominated by Wannier-Mott excitons, but molecular systems can host Frenkel excitons (FE) with unique properties. Here, we report a strong optical response in a class of monolayer molecular J-aggregates. The exciton exhibits giant oscillator strength and absorption (over 30% for monolayer) at resonance, as well as photoluminescence quantum yield in the range of 60-100%. We observe evidence of superradiance (including increased oscillator strength, bathochromic shift, reduced linewidth and lifetime) at room-temperature and more progressively towards low temperature. These unique properties only exist in monolayer owing to the large unscreened dipole interactions and suppression of charge-transfer processes. Finally, we demonstrate light-emitting devices with the monolayer J-aggregate. The intrinsic device speed could be beyond 30 GHz, which is promising for next-generation ultrafast on-chip optical communications.

6.
BMC Cancer ; 19(1): 1135, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752767

RESUMO

BACKGROUND: Post-transplant lymphoproliferative disorders (PTLDs) represent a spectrum of heterogenetic lymphoid proliferations. PTLD is a serious complication that affects the long-term survival of kidney transplant patients. Imaging examination is an important method for detecting and diagnosing PTLD. Contrast-enhanced ultrasonography (CEUS) and CEUS-guided biopsy are important modalities for tumor detection and diagnosis. In this case, we describe a 69 years old man in whom a native kidney PTLD was confirmed by CEUS. CASE PRESENTATION: A 69-year-old male patient who had a kidney transplant 1 year earlier presented with 3 months of progressive myasthenia of both lower limbs associated with amyotrophy and weight loss. Although positron emission tomography/computed tomography (PET-CT) showed a high metabolic lesion in the untransplanted kidney, abdominal contrast enhanced computed tomography cannot detect the lesion in the atrophic left kidney. The above examinations showed that the transplanted kidney was normal. CEUS can detect a homogeneously enhanced lesion in the same location as PET-CT. Subsequently, a biopsy was performed under CEUS guidance, and the final pathological diagnosis was diffuse large B-cell lymphoma. The patient then received the R-CHOP treatment. Unfortunately, pulmonary thromboembolism occurred 2 weeks later, and the patient's condition was not alleviated through active treatment. Finally, the patient's family gave up treatment, and the patient was discharged. CONCLUSION: The case suggested that CEUS was a valuable imaging method for patient with renal transplantation to detect and diagnose of PTLD.

7.
Int Immunopharmacol ; 77: 105948, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31629216

RESUMO

OBJECTIVE: The role of iNKT cells was investigated in chronic adipose tissue inflammation in obese mice after administration of α-GalCer in different pathways. METHODS: C57BL/6J mice were fed high-fat diet (HFD) for 12 weeks to establish the obese mouse model. The pathology of adipose tissue was observed by H&E staining. The rates of iNKT cells, macrophages and cell subsets in adipose tissue were detected by FCM. Cytokine levels in serum and adipose tissue lymphocyte-stimulated supernatants were assessed with the CBA kit. The expression levels of related transcription factor in adipose tissue were detected by Western blot. RESULTS: The proportions of iNKT cells, iNKT10 cells and M2 macrophages were decreased, while those of iNKT1 and M1 macrophages were increased in adipose tissue of HFD-fed mice. The expression levels of the related transcriptional proteins E4BP4 and Arg-1 were decreased while iNOS expression was increased in adipose tissue. Administration of α-GalCer by subcutaneous injection resulted in increased rates of iNKT10 cells and M2 macrophages, and decreased amounts of M1 macrophages in adipose tissue of HFD-fed mice. The expression of E4BP4 and Arg-1 were up-regulated, but iNOS was down-regulated. Meanwhile, infiltration of inflammatory cells into adipose tissue was further reduced. CONCLUSION: The imbalance between the proportions of iNKT1 and iNKT10 cells may be involved in the development of chronic inflammation in obese adipose tissue. Administration of α-GalCer by subcutaneous injection in HFD-fed mice activates adipose tissue iNKT10 cells, which promote M2 macrophage polarization and improve chronic inflammation in obese adipose tissue.

8.
Foods ; 8(10)2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31618925

RESUMO

Commercial caseinate and two gelatins from bovine and fish skin were hydrolyzed by alcalase, and used at 2 g/kg in skimmed bovine milk that was then fermented with a commercial direct vat set starter, to clarify different effects of these hydrolysates on acidification and textural attributes of set-style yogurt samples. Compared with the fermentation of the yogurt sample without hydrolysate addition, the two gelatin hydrolysates in the yogurt samples endowed lower titratable acidity but higher pH values and thus delayed yogurt fermentation, while the caseinate hydrolysate showed an effect opposite to the two gelatin hydrolysates. The two gelatin hydrolysates induced worse quality attributes for the resultant yogurt samples, including higher syneresis extent, smaller hysteresis loop areas, and lower values in these textural indices like hardness, adhesiveness, apparent viscosity, elastic and viscous moduli. However, the caseinate hydrolysate led to improved quality attributes. Moreover, bovine gelatin hydrolysate always had a greater negative effect than fish gelatin hydrolysate on yogurt acidification and texture. It is concluded that these gelatin hydrolysates could confer the yogurt with intended bio-activities of gelatin hydrolysates but negatively impact yogurt acidification and texture, while the caseinate hydrolysate might be helpful for yogurt processing by shortening fermentation time and improving yogurt texture.

9.
Microsc Microanal ; 25(5): 1201-1212, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31407647

RESUMO

Phase retrieval is necessary for propagation-based phase-contrast imaging (PB-PCI). Arhatari established a model for predicting the impact of the sample-to-detector distance and the system noise on the phase retrieval performance. We have extended Arhatari's model to account for the parameters of excessive source size, finite detector resolution, and geometrical magnification for more practical cases. However, there exist interaction effects among these parameters resulting in difficulty of predicting the phase retrieval performance. In this study, we found that optimizing the trade-off among these parameters for phase retrieval is consistent with the improvement of edge enhancement to noise ratio (EE/N) in the "forward problem" of the PB-PCI. Hence, we engaged in establishing a relationship between EE/N and phase retrieval performance in terms of the "forward problem" and "inverse problem" of the PB-PCI, respectively. Our results showed that, at fixed detector resolution, phase retrieval from the phase-contrast projections at the same EE/N level resulted in the consistent phase retrieval performance. Therefore, the performance of phase retrieval can be predicted based on the EE/N level and be quantitatively optimized by increasing EE/N.

10.
Angew Chem Int Ed Engl ; 58(45): 16082-16086, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31432576

RESUMO

Two-dimensional molecular crystals (2DMCs) open a new door for the controllable growth of 2D materials by molecular design with a energy gap and solution processability. However, the growth of 2DMCs with defined molecular layers remains full of challenges. Herein, we report a novel method to produce various 2DMCs with a defined number of molecular layers. When the surface tension and viscosity are tuned to control the spreading of the solution on the liquid surface, large-area quasi-freestanding 2DMCs from bulk size down to the monolayer limit are obtained, which makes it possible to probe the intrinsic layer-dependent optoelectronic properties of organic semiconductors down to the physical limit, and paves the way for the application of 2DMCs in new optoelectronic devices and technologies.

11.
Aging (Albany NY) ; 11(16): 5992-6013, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31444317

RESUMO

Ultraviolet (UV) irradiation from the sunlight is a major etiologic factor for premature skin aging. Long noncoding RNAs (lncRNAs) are involved in various biological processes, and their roles in UV irradiation-induced skin aging have recently been described. Previously, we found that the lncRNA RP11-670E13.6 was up-regulated and delayed cellular senescence in UVB-irradiated primary human dermal fibroblasts. Here, we performed further investigations of RP11-670E13.6 function. The results showed that this lncRNA directly bound to miR-663a and functioned as a sponge for miR-663a to modulate the derepression of Cdk4 and Cdk6, thereby delaying cellular senescence during UV irradiation-induced skin photoaging. Moreover, we found that RP11-670E13.6 may facilitate DNA damage repair by increasing ATM and γH2A.X levels. In addition, heterogeneous nuclear ribonucleoprotein H physically interacted with RP11-670E13.6 and blocked its expression. Collectively, our results suggested that the RP11-670E13.6/miR-663a/CDK4 and RP11-670E13.6/miR-663a/CDK6 axis, which may function as competitive endogenous RNA networks, played important roles in UVB-induced cellular senescence.

12.
Immunogenetics ; 71(7): 489-499, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31297569

RESUMO

Epigenetic modifications have been shown to be important for immune cell differentiation by regulating gene transcription. However, the role and mechanism of histone methylation in the development and differentiation of iNKT cells in rheumatoid arthritis (RA) mice have yet to be deciphered. The DBA/1 mouse RA model was established by using a modified GPI mixed peptide. We demonstrated that total peripheral blood, thymus, and spleen iNKT cells in RA mice decreased significantly, while iNKT1 in the thymus and spleen was increased significantly. PLZF protein and PLZF mRNA levels were significantly decreased in thymus DP T cells, while T-bet protein and mRNA were significantly increased in thymus iNKT cells. We found a marked accumulation in H3K27me3 around the promoter regions of the signature gene Zbtb16 in RA mice thymus DP T cells, and an accumulation of H3K4me3 around the promoters of the Tbx21 gene in iNKT cells. The expression levels of UTX in the thymus of RA mice were significantly reduced. The changes in the above indicators were particularly significant in the progressive phase of inflammation (11 days after modeling) and the peak phase of inflammation (14 days after modeling) in RA mice. Developmental and differentiation defects of iNKT cells in RA mice were associated with abnormal methylation levels (H3K27me3 and H3K4me3) in the promoters of key genes Zbtb16 (encoding PLZF) and Tbx21 (encoding T-bet). Decreased UTX of thymus histone demethylase levels resulted in the accumulation of H3K27me3 modification.


Assuntos
Artrite Reumatoide/patologia , Lisina/metabolismo , Células T Matadoras Naturais/patologia , Regiões Promotoras Genéticas , Timo/fisiologia , Animais , Artrite Experimental/patologia , Diferenciação Celular , Epigênese Genética , Regulação da Expressão Gênica , Histona Desmetilases/genética , Histona Desmetilases/metabolismo , Metilação , Camundongos Endogâmicos DBA , Proteína com Dedos de Zinco da Leucemia Promielocítica/genética , Proteína com Dedos de Zinco da Leucemia Promielocítica/metabolismo , Baço/patologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo
13.
Sci Data ; 6(1): 122, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31308375

RESUMO

Tea is a globally consumed non-alcohol beverage with great economic importance. However, lack of the reference genome has largely hampered the utilization of precious tea plant genetic resources towards breeding. To address this issue, we previously generated a high-quality reference genome of tea plant using Illumina and PacBio sequencing technology, which produced a total of 2,124 Gb short and 125 Gb long read data, respectively. A hybrid strategy was employed to assemble the tea genome that has been publicly released. We here described the data framework used to generate, annotate and validate the genome assembly. Besides, we re-predicted the protein-coding genes and annotated their putative functions using more comprehensive omics datasets with improved training models. We reassessed the assembly and annotation quality using the latest version of BUSCO. These data can be utilized to develop new methodologies/tools for better assembly of complex genomes, aid in finding of novel genes, variations and evolutionary clues associated with tea quality, thus help to breed new varieties with high yield and better quality in the future.

14.
Int Immunopharmacol ; 74: 105727, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284229

RESUMO

The existence of association between the subpopulation of iNKT cells with different functions and nonalcoholic fatty liver disease has not been confirmed. To investigative the role of iNKT cells in the pathogenesis of nonalcoholic fatty liver disease, we established a non-alcoholic fatty liver model by feeding C57BL/6J mice for 12 weeks with a high-fat diet and injecting α-GalCer through different routes to activate hepatic iNKT cells. The liver of the mice fed a high-fat diet (HFD) had severe hepatic steatosis appearance, elevated pro-inflammatory cytokines and reduced anti-inflammatory cytokines in the liver, and high serum levels of TC, LDL, HDL, and ALT. Our results showed that the percentage of iNKT cells in the liver of the HFD-fed mice was lower than that of the control mice. The expression levels of the related transcription factor of T-bet increased but that of GATA-3 decreased in the HFD-fed mice. The administration of α-GalCer by intraperitoneal injection resulted in increasing of hepatic iNKT and iNKT2 cells but decreasing of hepatic iNKT1 cells, and the expression of GATA-3 and anti-inflammatory cytokine (IL-4) was increased in the liver, and hepatic steatosis was ameliorated in the HFD-fed mice. The administration of α-GalCer by subcutaneous injection resulted in a decrease in hepatic iNKT and iNKT2 and an augmentation of hepatic iNKT1 cells. However, hepatic steatosis was not significantly improved. We concluded that the intraperitoneal injection with α-GalCer effectively improved hepatic steatosis, according to increasing the number of hepatic iNKT2 cells. The precise mechanism requires further exploration.

15.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 27(3): 935-941, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31204958

RESUMO

OBJECTIVE: To compare the efficacy of directional erythroid differentiation in different serum free culture systems and to screen the optimal culture systems for inducing the differentiation of umbilical cord blood hematopoietic stem and progenior cells (HSPC) to erythroid cells. METHODS: The CD34+ cells from umbilical blood munonuclear cells were sorted by using the magnetic beads, and were inoculated into 3 different of culture systems (system 1, 2 and 3 respectively), to induce erythrold differentiation by 3 stage culture. The living cells were counted in different differentiation stages and were observed by Wright-Giemsa staining; the expression of CD71 and CD235a on cell surface was detected by flow cytometry, the erythroid differentiation pteency was detected via colony-forming test. RESULTS: The ability of system 2 to promote the HSPC proliferation was the strongest, the efficacy of system 3 to promote the erythroid differentiation of HSPC was the most optimal; the proliferation ability of cells cultured in system 2 for 2-15 days all was higher than that of cells cutured in system 1 and 3 (P<0.05). The flow cytometry detection showed that the expression of CD71 and CD235a on surface of cells cultured in system 3 was the highest, the CD235a percentage on day 15 of differentiation in system 3 was (92.33±3.89)%, that in system 2 was (84.67±3.12)%, while that in system 1 was (72.17±6.83)% (P<0.05). Cell morplologic detection showed that throid differentiation was accelerated on day 12, the percentage of orthochromatic erythrocytes in system 3 was (67.67±2.08)% which was 10.69 and 25.34 times higher than that in system 2 and 1 respectively (P<0.05). The colony-forming test showed the ratio of BFU-E in system 3 increased gradually on day 3-9 (r=0.99, P<0.05), which was significanlly higher than that in system 2 and 1 on day 9 (90.35±5.52% vs 77.06±2.26% and 74.50±3.95%). CONCLUSION: Culture system 3 is the most effective serum-free erythroid differentiation system, and the culture system 2 is the most powerful HSPC proliferation system. This study results provide a technical basis for further efficiently increasing and inducing the erythroid proliferation and differentiation of HSPC, and also provide culture system in vitro for the clinical application and basic research.


Assuntos
Células Precursoras Eritroides , Sangue Fetal , Antígenos CD34 , Diferenciação Celular , Células Cultivadas , Meios de Cultura Livres de Soro , Humanos
16.
Food Funct ; 10(4): 2244-2253, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30958500

RESUMO

In order to investigate the protective effects of allyl methyl trisulfide (AMTS) on acetaminophen (APAP)-induced hepatotoxicity, 75 KM mice were randomized into 5 groups, i.e. a control group, an APAP group, and three AMTS/APAP groups. The mice in the AMTS/APAP groups and APAP group were gavaged with 25-100 mg kg-1 AMTS or corn oil for 7 d followed by intraperitoneal injection of 300 mg kg-1 APAP, while mice in the control group were treated with a vehicle. We found that AMTS significantly attenuated APAP-induced hepatotoxicity shown by reduced mortality, decreased serum aminotransferase activities, and improved liver histological morphology. APAP overdose resulted in a significant increase of hepatic malondialdehyde (MDA) level and a decrease of the protein levels of NQO-1, γ-GCS, HO-1, and SOD, which was suppressed by AMTS pretreatment. Furthermore, AMTS inhibited the APAP-induced elevation of hepatic p62 and LC3II protein levels. Interestingly, AMTS attenuated the APAP-induced decline of hepatic CYP2E1 protein levels, but AMTS alone led to the decrease of CYP2E1 protein expression in mouse liver. Collectively, these data suggest that AMTS could attenuate APAP-induced hepatotoxicity by suppressing CYP2E1 and activating Nrf2.


Assuntos
Acetaminofen/efeitos adversos , Compostos Alílicos/administração & dosagem , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Citocromo P-450 CYP2E1/metabolismo , Fígado/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Substâncias Protetoras/administração & dosagem , Sulfetos/administração & dosagem , Alanina Transaminase/sangue , Animais , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/genética , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Citocromo P-450 CYP2E1/genética , Glutationa/metabolismo , Fígado/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Camundongos , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/metabolismo
17.
Nanotechnology ; 30(33): 335703, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30995621

RESUMO

The mechanical properties of two-dimensional (2D) materials are critical for their applications in functional devices as well as for strain engineering. Here, we report the Young's modulus and breaking strength of multilayered InSe, an emerging 2D semiconductor of the layered group III chalcogenide. Few-layer InSe flaks were exfoliated from bulk InSe crystal onto Si/SiO2 substrate with micro-fabricated holes, and indentation tests were carried out using an atomic force microscopy probe. In combination with both continuum analysis and finite element simulation, we measured the Young's modulus of multilayer 2D InSe (>5 L) to be 101.37 ± 17.93 GPa, much higher than its bulk counterpart, while its breaking strength is determined to be 8.68 GPa, approaching the theoretical limit of 10.1 GPa. Density functional theory calculations were also carried out to explain the insensitivity of Young's modulus to the layer count. It is found that 2D InSe is softer than most 2D materials, and exhibits breaking strength higher than that of carbon fiber, yet remaining more compliant, making it ideal for flexible electronics applications. The reliability of our method is also validated by measurement of graphene.

18.
Nanoscale ; 11(16): 7790-7797, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-30951064

RESUMO

Chemically-synthesized single-crystalline silver nanowire (AgNW) probes can combine the scanning tunneling microscopy (STM) technique with tip-enhanced Raman scattering spectroscopy (TERS) for complementary morphological and chemical information with nanoscale spatial resolution. However, its performance has been limited by the blunt nanowire tip geometry, the insulating surfactant layer coating AgNW surfaces, and the thermal-induced mechanical vibrations. Here, we report a reproducible fabrication method for the preparation of sharp-tip AgNW-based TERS probes. By removing the polyvinylpyrrolidone (PVP) surfactant molecules from the AgNW surfaces for stable electrical conductivity and controlling the protruding length with µm-level accuracy for improved mechanical stability, we demonstrate atomic-resolution STM imaging with the sharp-tip AgNW probe. Furthermore, the sharp-tip AgNW has an excellent TER enhancement (∼1.1 × 106), which is about 66 folds of that achieved by regular AgNWs. Our experiments demonstrate that AgNWs with clean interfaces and the proper tip geometry can provide reliable and reproducible STM and TER characterizations, which remove the hurdles preventing the implementation of AgNW in STM-based near-field optical applications for a broad community.

19.
Plant Biotechnol J ; 17(10): 1938-1953, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30913342

RESUMO

Tea is the world's widely consumed nonalcohol beverage with essential economic and health benefits. Confronted with the increasing large-scale omics-data set particularly the genome sequence released in tea plant, the construction of a comprehensive knowledgebase is urgently needed to facilitate the utilization of these data sets towards molecular breeding. We hereby present the first integrative and specially designed web-accessible database, Tea Plant Information Archive (TPIA; http://tpia.teaplant.org). The current release of TPIA employs the comprehensively annotated tea plant genome as framework and incorporates with abundant well-organized transcriptomes, gene expressions (across species, tissues and stresses), orthologs and characteristic metabolites determining tea quality. It also hosts massive transcription factors, polymorphic simple sequence repeats, single nucleotide polymorphisms, correlations, manually curated functional genes and globally collected germplasm information. A variety of versatile analytic tools (e.g. JBrowse, blast, enrichment analysis, etc.) are established helping users to perform further comparative, evolutionary and functional analysis. We show a case application of TPIA that provides novel and interesting insights into the phytochemical content variation of section Thea of genus Camellia under a well-resolved phylogenetic framework. The constructed knowledgebase of tea plant will serve as a central gateway for global tea community to better understand the tea plant biology that largely benefits the whole tea industry.

20.
Appl Opt ; 58(4): 863-870, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30874130

RESUMO

In brain functional diffuse optical tomography, conventional indirect approaches first separately reconstruct the spatial changes in the absorption coefficients at every time point and then calculate the spatial excited levels in terms of hemodynamic models. Direct approaches combine the two steps necessary in the indirect approaches and obtain the spatial excited levels directly. Although reconstruction quality has been improved by the direct approaches to some extent, they still lack sharp edges and suffer from low spatial resolution because of the ill-posedness of the inverse problems. In this paper, a priori sparsity is introduced to obtain the sparse solutions and further improve reconstruction quality. Simulation experiments are conducted to illustrate the expected performance improvements of the proposed approaches.


Assuntos
Algoritmos , Encéfalo/fisiologia , Hemodinâmica/fisiologia , Tomografia Óptica/métodos , Simulação por Computador , Humanos , Processamento de Imagem Assistida por Computador , Fatores de Tempo
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