Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 103
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Mater Sci Eng C Mater Biol Appl ; 106: 110188, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753331

RESUMO

The traditional electrospinning process produces dense two-dimensional (2D) nanofiber (NF) sheets that limit cell infiltration and proliferation. Our previous study demonstrated that 3D NF sheets could be formed on an NF collector surface mounted with multiple movable needles through the corona discharge. In this study, we developed a programmed electrospun 3D NF collector. It can precisely control the moving speed of NF collector during electrospinning; thereby fabricating 3D NFs with desired microstructures (pore size, pore volume, and interconnectivity). Four types of polycaprolactone (PCL) 3D NF matrices with different microstructures can be obtained concurrently on the NF collector surface, which are set by different forward moving speed of the NF collector device: NF-zero (no move, as control), NF-low (0.085 mm/min), NF-mid (0.158 mm/min) and NF-high (0.232 mm/min). A linear increase of the NF sheet thickness (from 0.21 mm to 0.91 mm) was recorded with accelerating collector movement. Quantitative analysis using scanning electron microscopy (SEM), micro-computed tomography (µ-CT), and confocal laser scanning microscopy (CLSM) showed a monotonic increase of pore size and porosity with the increase of collector moving speeds. The collector movement also impacted the crystallinity and mechanical properties of the NFs. When prepared at high collector speed, the NFs showed improved proliferation and differentiation (p < .05) of pre-osteoblastic MC3T3 cells compared to the NFs from the static collector. A programmed NF collector device allows for the reproducible, precise and continuous fabrication of 3D NFs with tailorable geometry and microstructures. This simple, controllable, one-step process could promote the clinical translation of electrospun NFs in tissue engineering and regenerative medicine.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31692185

RESUMO

Cage-type compounds offer molecule-level confined spaces with different sizes, shapes, and functional groups for various molecule guests to achieve some specific behaviors/functions, such as ultrahigh affinity of host-guest recognition, multi-tunable photophysical property, and highly-stereoselective/photo-driven catalysis. Herein, we report the synthesis and characterization of three-dimensional tetraphenylethene-based octacationic cage with fluorescent property and host-guest recognition via CH•••π, π-π, and/or electrostatic interactions for polycyclic aromatic hydrocarbons (e.g. coronene) in organic media and water-soluble dyes (e.g. sulforhodamine 101) in aqueous media, respectively. The X-ray structure of cage⸧coronene exhibits a cuboid internal cavity with the size of approximate 17.2 Å (length) × 11.0 Å (width) × 6.96 Å (height) and "hamburger"-type host-guest complexes, which are hierarchically stacked into 1D nanotube and 3D supramolecular framework. Compared to its host-guest complexes, free cage possesses a similar but empty cavity in the crystalline state, indicating that the stability and rigidity of cage itself are consistent both in the absence and presence of guest. Furthermore, as a single-molecular fluorescent platform, tetraphenylethene-based octacationic cage with dye guests (e.g. sulforhodamine 101) can form host-guest complex with higher absolute quantum yield ( Φ F = 28.5%), larger excitation-emission gap (Δλ ex-em = 211 nm), longer lifetime (τ = 7.0 ns), compared to guest ( Φ F = 10.5%; Δλ ex-em = 11 nm; τ = 4.9 ns); and purer emission with a narrow full width at half-maxima (Δλ FWHM = 38 nm), compared to host (Δλ FWHM = 111 nm), respectively. This study provides insight into construct cationic cage with both fluorescence and host-guest properties, and might facilitate further design of multifunctional cages and other fluorescent supramolecular systems based on host-guest recognition.

3.
Sci Rep ; 9(1): 16960, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31740701

RESUMO

Astatine-211 is an attractive radionuclide for use in targeted alpha therapy of blood-borne diseases and micrometastatic diseases. Efficient isolation methods that can be adapted to robust automated 211At isolation systems are of high interest for improving the availability of 211At. Based on the early studies of Bochvarova and co-workers involving isolation of 211At from irradiated thorium targets, we developed a method for 211At isolation from bismuth targets using tellurium-packed columns. Dissolution of irradiated bismuth targets is accomplished using HNO3; however, 211At is not captured on the Te column material in this matrix. Our method involves slow addition of aqueous NH2OH·HCl to the Bi target dissolved in HNO3 to convert to a HCl matrix. The amount of NH2OH·HCl was optimized because (1) the quantity of NH2OH·HCl used appears to affect the radiolabeling yield of phenethyl-closo-decaborate(2-) (B10)-conjugated antibodies and (2) reducing the volume of NH2OH·HCl solution can effectively shorten the overall isolation time. A proof-of-concept semi-automated process has been demonstrated using targets containing ~0.96 GBq (~26 mCi) of 211At. High isolation yields (88-95%) were obtained. Radiochemical purity of the isolated 211At was assessed by radio-HPLC. Concentrations of Bi and Te contaminants in the 211At and the astatinated antibodies were evaluated using ICP-MS.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31721336

RESUMO

RATIONALE: Interactions of drug molecules and proteins play an important role in physiological and pathological processes in vivo. It is of significance to establish a reliable strategy for studying protein-drug ligand interactions and would be helpful for the design and screening of new drugs in pharmacological research. METHODS: The interactions between four indole alkaloids (IAs) extracted from Ophiorrhiza japonica and myoglobin (Mb) protein were investigated by using a multi-spectrometric and computational method of native electrospray ionization mass spectrometry (Native ESI-MS), hydrogen/deuterium exchange mass spectrometry (HDX-MS), circular dichroism (CD) and molecular docking (MD). RESULTS: The IA bound-Mb complexes were analyzed by native ESI-MS, with the obtained stoichiometry of protein-ligand at 1:1, 1:2, 1:3, respectively. Binding constants were measured according to the interpretation of MS spectra. MD complemented MS measurement, probed that the binding sites and modes of four IAs to Mb. Analyses of CD and HDX-MS demonstrated that the exposure to IAs could affect the conformation of Mb by decreasing the α-helix content and make Mb more susceptible to HDX at the backbone. CONCLUSIONS: A new mass spectrometry-based integrated analysis method has been developed to successfully study the interactions of Mb and IAs extracted from Ophiorrhiza japonica. The experimental and calculation results have good consistency, revealing all of the four IA molecules could bind to Mb to form 1:1, 1:2 and 1:3 Mb-IA complexes, respectively. The order of binding ability of these IAs to Mb was Ophiorrhine B > Compound C > Ophiorrhine A > Compound D. CD and HDX-MS results indicated that binding with IAs destabilizes resulted of Mb. HDX-MS analysis suggests that Mb becomes more accessible to HDX, indicating that IAs binding destabilizes the structure of Mb. In addition, interacting with IAs affected the overall structure of Mb, ascribed to the decrease of α-helix content and less folding of backbone.

5.
Langmuir ; 35(45): 14532-14542, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31635451

RESUMO

We report pH-responsive liquid crystalline lipid nanoparticles, which are dual-loaded by Brucea javanica oil (BJO) and doxorubicin hydrochloride (DOX) and display a pH-induced inverted hexagonal (pH = 7.4) to cubic (pH = 6.8) to emulsified microemulsion (pH = 5.3) phase transition with a therapeutic application in cancer inhibition. BJO is a traditional herbal medicine that strongly inhibits the proliferation and metastasis of various cancers. Doxorubicin is an antitumor drug, which prevents DNA replication and hampers protein synthesis through intercalation between the base pairs of the DNA helices. Its dose-dependent cardiotoxicity imposes the need for safe delivery carriers. Here, pH-induced changes in the structural and interfacial properties of designed multicomponent drug delivery (monoolein-oleic acid-BJO-DOX) systems are determined by synchrotron small-angle X-ray scattering and the Langmuir film balance technique. The nanocarrier assemblies display good physical stability in the studied pH range and adequate particle sizes and ζ-potentials. Their interaction with model lipid membrane interfaces is enhanced under acidic pH conditions, which mimic the microenvironment around tumor cells. In vitro cytotoxicity and apoptosis studies with BJO-DOX dual-loaded pH-switchable liquid crystalline nanoparticles are performed on the human breast cancer Michigan Cancer Foundation-7 (MCF-7) cell line and MCF-7 cells with doxorubicin resistance (MCF-7/DOX), respectively. The obtained pH-sensitive nanomedicines exhibit enhanced antitumor efficacy. The performed preliminary studies suggest a potential reversal of the resistance of the MCF-7/DOX cells to DOX. These results highlight the necessity for further understanding the link between the established pH-dependent drug release profiles of the nanocarriers and the role of their pH-switchable inverted hexagonal, bicontinuous cubic, and emulsified microemulsion inner organizations for therapeutic outcomes.

6.
J Mater Chem B ; 7(30): 4706-4716, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31364685

RESUMO

Mitochondria-targeting peptides represent an emergent tool for cancer inhibition. Here supramolecular assemblies of novel amphiphilic cell-penetrating peptides for targeting cancer cell mitochondria are reported. The employed strategy aims at amplifying the apoptotic stimuli by weakening the mitochondrial VDAC1 (voltage-dependent anion channel-1)-hexokinase-II (HK-II) interaction. Peptide engineering is performed with the N-terminus of the HK-II protein, which binds to VDAC1. First, a designed positively charged segment (pKV) is anchored to the specific 15 amino acid sequence (MIASHLLAYFFTELN) to yield a cell-penetrating peptide (pHK-pKV). Second, a lipid chain (Pal) is conjugated to the N-terminus of pHK-pKV in order to enhance the intracellular delivery of the HK-II scaffold. The self-assembly properties of these two synthetic peptides are investigated by synchrotron small-angle X-ray scattering (BioSAXS) and cryogenic transmission electron (cryo-TEM) imaging, which evidence the formation of nanoassemblies of ellipsoid-like shapes. Circular dichroism (CD) spectroscopy demonstrates the induction of partial α-helical structures in the amphiphilic peptides. Confocal microscopy reveals the specific mitochondrial location of Pal-pHK-pKV assemblies in human non-small cell lung cancer (NSCLC) A549 cells. The cytotoxicity and apoptotic studies indicate the enhanced bioactivity of Pal-pHK-pKV self-assembled reservoirs, which cause massive A549 cell death with regard to pHK-pKV. Of significance, Pal-pHK-pKV treatment of non-cancerous NCM460 cells resulted in substantially lower cytotoxicity. The results demonstrate the potential of self-assembled lipo-peptide (HK-II-derived) conjugates as a promising strategy in cancer therapy.

7.
Science ; 365(6453): 591-595, 2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31395783

RESUMO

Although ß-CsPbI3 has a bandgap favorable for application in tandem solar cells, depositing and stabilizing ß-CsPbI3 experimentally has remained a challenge. We obtained highly crystalline ß-CsPbI3 films with an extended spectral response and enhanced phase stability. Synchrotron-based x-ray scattering revealed the presence of highly oriented ß-CsPbI3 grains, and sensitive elemental analyses-including inductively coupled plasma mass spectrometry and time-of-flight secondary ion mass spectrometry-confirmed their all-inorganic composition. We further mitigated the effects of cracks and pinholes in the perovskite layer by surface treating with choline iodide, which increased the charge-carrier lifetime and improved the energy-level alignment between the ß-CsPbI3 absorber layer and carrier-selective contacts. The perovskite solar cells made from the treated material have highly reproducible and stable efficiencies reaching 18.4% under 45 ± 5°C ambient conditions.

8.
Acad Radiol ; 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31303576

RESUMO

RATIONALE AND OBJECTIVES: The aim of our study is to evaluate the severity of esophageal varices (EV), based on the computed tomographic portography (CTP) measurement of EV in the distal esophagus and to assess the prediction value of EV volume. PATIENTS AND METHODS: A total of 53 EV patients examined by CTP within 4 weeks of upper endoscopy were evaluated, the patients were divided into a nonconspicuous EV group (mild-to-moderate EV, n = 28) and a conspicuous EV group (severe EV, n = 25) according to endoscopy results. The diameter, cross-sectional surface area (CSA), and volume of EV were measured independently using 3D-slicer (Boston) by two experienced abdominal radiologists blinded to endoscopy findings. The averaged values measured by the two observers were used in the final dataset, these indicators' predictive performances were studied by using receiver operating characteristic curve analysis, and the area under the curve (Az) and the cutoff values were calculated to distinguish mild-to-moderate from severe EV. RESULTS: The Az values of volume, diameter and CSA in differentiating severe EV were 0.817, 0.794, and 0.784 for observer-1, corresponding values for observer-2 were 0.796, 0.774, and 0.707, there was almost perfect interobserver agreement for all measurements. All indices were larger in the conspicuous group than the nonconspicuous group in both observers (p ≤ 0.01). In the final dataset, application of a 654.0-mm3-volume criterion yielded sensitivity, specificity of 96%, 50%, application of a 5.2-mm-diameter criterion yielded sensitivity, specificity of 80%, 75%, and application of a 68.6-mm2-CSA criterion yielded sensitivity, specificity of 52%, 93%. CONCLUSION: The volume of EV could be used as a new effective indictor for evaluating EV, and use of volume, diameter, and CSA of EV based on CTP allows discrimination between mild-to-moderate and severe EV in cirrhotic patients.

9.
ACS Appl Mater Interfaces ; 11(33): 29630-29640, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31337206

RESUMO

Photothermal conversion efficiency (η) of gold nanorods (GNRs) can be tuned by enlarging the aspect ratio and forming the core-shell structure. Herein, an easy synthesis method is developed to construct the core-shell GNR@LDH nanostructure with GNRs and layered double hydroxides (LDHs). The interaction between Au and LDHs results some electron deficiency on the surface of Au and the more electrons induce more thermal energy conversion. The η value of GNR@LDH can reach up to 60% under the 808 nm laser irradiation, which is a significant enhanced conversion efficiency compared with the reported GNR-based photothermal therapy materials. CTAB (cetyltrimethyl ammonium bromide) can be replaced totally during the synthesis process, and GNRs maintain a good dispersion in LDHs. This core-shell composite GNR@LDH can be applied in photothermal, antibacterial, tumor therapy and biological imaging with low dosage and nontoxicity.

10.
Funct Plant Biol ; 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31234961

RESUMO

Signal transduction mediated by photoreceptors regulates many physiological processes during plant growth and development including seed germination, flowering and photosynthesis, which are also regulated by hydrogen sulfide (H2S). However, studies of the connection between the vital environmental factors - light and the significant endogenous gasotransmitter - H2S, is lacking. Here, the seedlings of foxtail millet were used to reveal the mechanism of light regulation in H2S generation. Results showed that seedling hypocotyl elongation was promoted by H2S, but inhibited by HA under dark or white light condition. H2S contents in hypocotyl increased at first under red, blue or white light then decreased, and the duration of increase under white light was longer than under red or blue light. The activity of cysteine desulfhydrases, which catalyse H2S generation, was increased by red light but decreased by blue and white light. The expressions of cysteine desulfhydrases coding genes LCD1 and LCD2 were promoted by red or white light, but inhibited by blue light. In contrast, DES gene was promoted by white light but inhibited by red or blue light. In addition, the activities of LCDs were regulated by the phosphorylation mediated by photoreceptors PHYB and CRY1/CRY2. Finally, there are two pathways of light regulating H2S production, including a rapid process that involves the modification of phosphorylation on LCDs protein mediated by photoreceptors directly or indirectly, as well as a slower process that involves in regulating the expressions of LCDs and DES genes. This discovery has potential value for the application of H2S in agricultural production protecting the crops from unsuited light condition.

11.
Int J Biol Sci ; 15(6): 1276-1286, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31223286

RESUMO

The transcriptional coactivator CREB-binding protein (CBP) and p300 are adenoviral E1A-binding proteins involved in various cellular processes, including embryonic development, homeostasis, cell differentiation and transcription activation. Previous study suggested that synthetic lethality between CBP and p300 inhibition in lung and hematopoietic cancers. However, the underlying mechanism of CBP and p300 paralog in bladder cancer remains unknown. In this study, we discovered that combined CBP and p300 inhibition impaired cell proliferation and induced apoptosis of bladder cancer cells and normal bladder urothelial cell via decreasing c-Myc expression. Then, we employed the dCas9-KRAB system, hTERT promoter and hUPII promoter to construct an CRISPR interference system which could specifically repress CBP and p300 expression and cause lethality in bladder cancer cells in vitro. The CRISPR interference system we constructed could specifically inhibit the progression of bladder cancer, providing a novel strategy to fight against bladder cancer.

12.
Sci Total Environ ; 686: 838-846, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31195291

RESUMO

A large-scale and high-dropout water-level-fluctuation zone (WLFZ) was formed by the construction of cascaded large dam in the southwest hydropower base of China. The original land use patterns changed significantly by the formation of the WLFZ, which possibly affected the soil organic carbon (SOC) stocks and local carbon cycle. However, little is known about the effects of land uses before dam construction on the SOC stocks in the WLFZ. To address this, we chose the Nuozhadu mega reservoir built in 2014 in the upper Mekong River basin as our study area. We established five sampling transects around the reservoir and sampled them in 2015. Each transect contained three vertical sampling lines representing three land-use types: natural forest, farmland, and rubber plantations. SOC stocks were determined in the WLFZ and in the infralittoral reference zone (IRZ), and the interactions among SOC, land uses, soil erosion, inundation, and other soil physicochemical properties were analyzed to establish the factors controlling SOC in the WLFZ. The average soil organic carbon density (SOCD) was not significantly different between the WLFZ and IRZ, but it differed significantly among the three types of land uses. The SOC stocks in natural forests of the WLFZ and IRZ were significantly greater than those in the other land use types. The SOCD decreased with increasing elevation in the natural forest and rubber plantation in the WLFZ, while no significant trend was found in farmland. These results indicated that the construction of a large dam in southwestern China may not lead to significant changes in regional SOC stocks, but it can result in the redistribution of SOC in the large-scale and high-dropout WLFZ. Land use before dam construction can affect the background concentrations of SOC, soil physicochemical properties, and soil erosion rate in the WLFZ, which controlled the redistribution of SOC.

13.
Small ; 15(30): e1902352, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31183957

RESUMO

Photodynamic therapy (PDT) and photothermal therapy (PTT) are two kinds of treatment for tumors. Herein, a new aggregation-induced emission (AIE)gen (MeO-TPE-indo, MTi) is synthesized with a D-π-A conjugated structure. MTi, which has an electron donor and an acceptor on a tetraphenylethene (TPE) conjugated skeleton, can induce the effective generation of reactive oxygen species (ROS) for PDT. With the guide of the indolium group, MTi can target and image mitochondrion selectively. In order to get good dispersion in water and long-time retention in tumors, MTi is modified on the surface of polydopamine nanoparticles (PDA NPs) to form the nanocomposite (PDA-MeO-TPE-indo, PMTi) by π-π and hydrogen interactions. PMTi is a nanoscale composite for imaging-guided PDT and PTT in tumor treatment, which is constructed with AIEgens and PDA for the first time. The organic functional molecules are combined with nanomaterials for building a multifunctional diagnosis and treatment platform by utilizing the advantages of both sides.

14.
Nan Fang Yi Ke Da Xue Xue Bao ; 39(4): 422-427, 2019 Apr 30.
Artigo em Chinês | MEDLINE | ID: mdl-31068285

RESUMO

OBJECTIVE: To investigate the association between alcohol drinking and all-cause death in patients with ischemic stroke. METHODS: Between January, 2010 and July, 2018, consecutive patients with first-episode ischemic stroke admitted in the West China Hospital, Sichuan University were enrolled, and all the patients were followed up every 3 months.Chi-square test was used to compare the differences in the baseline characteristics between the pre-stroke drinkers and the nondrinkers.The Cox regression model was used to analyze the effects of drinking status, drinking years, drinking frequency, average single alcohol intake before stroke and drinking status during the follow-up period on the mortality of patients after discharge. RESULTS: A total of 855 patients with ischemic stroke were enrolled, and deaths occurred in 140 of these patients.Chi-square test showed significant differences in gender (P < 0.001), weekly physical exercise time (P=0.035), smoking (P < 0.001), and heart disease (P < 0.001) between the pre-stroke drinkers and nondrinkers.Multivariate Cox regression analysis showed that drinking during the follow-up period (P=0.001), drinking for less than 28 years before stroke (P=0.035) and a moderate drinking frequency (5 to 20 times per month for males and 4 to 9 times per month for females; P=0.030) were associated with a lowered risk of death after discharge.No significant effects of pre-stroke drinking status or average single alcohol intake were found on death after ischemic stroke. CONCLUSIONS: The drinking years and drinking frequency before stroke and drinking status during the follow-up period are related to the all-cause mortality in patients with ischemic stroke.Investigations of the more specific variables of drinking behaviors during the follow-up period are needed to further clarify the association between drinking and death after ischemic stroke.


Assuntos
Consumo de Bebidas Alcoólicas/efeitos adversos , Isquemia Encefálica , Acidente Vascular Cerebral , Isquemia Encefálica/etiologia , China , Feminino , Seguimentos , Humanos , Masculino , Fatores de Risco , Acidente Vascular Cerebral/etiologia
15.
J Am Chem Soc ; 141(21): 8412-8415, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31026395

RESUMO

Here we report one-pot synthesis of tetraphenylethene-based tetracationic dicyclophane (1) and its self-assembly behaviors with aggregation-induced emission (AIE) and light-harvesting function. Confirmed by X-ray crystal structure and high resolution transmission electron microscopy, this tetracationic dicyclophane can self-assemble into a 3D supramolecular framework to form crystalline nanospheres (2) finally, which exhibits a strong emission (ΦF = 97.7%) via AIE effect in aqueous solution. Interestingly, AIE-active 2 as a single-molecule-based fluorescent supramolecular platform can encapsulate an organic dye (e.g., Nile red) to form light-harvesting nanospheres (3) further with a large red-shift (Δλ = ∼70 nm), highly efficient energy-transfer ability (ΦET = 77.5%), and high antenna effect (14.3).

16.
Analyst ; 144(10): 3381-3388, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-30984924

RESUMO

Hydrogen sulfide (H2S) exists in the cytosol and mitochondria of mammalian cells as a signaling molecule. Scientists have explored many important physiological functions of H2S, such as regulating vasodilator relaxation, protecting living cells and avoiding damage. The measurement of H2S is therefore necessary for exploring the biological function of cells and tissues. Herein, we report the design and synthesis of a new aggregation-induced emission luminogen (AIEgen) with greater conjugation and more positive charges, based on previous research on mitochondrial-targeted luminogens. The Indo-TPE-Indo can enter cells rapidly, as compared with an AIEgen with only one indolium (TPE-indo), and can selectively recognize HS- in mitochondria with the nucleophilic reaction of indolium and HS-. The linear range (1-100 µM) of HS- sensing can satisfy the requirement for HS- concentration in living cells and tumors.


Assuntos
Corantes Fluorescentes/química , Sulfeto de Hidrogênio/análise , Indóis/química , Mitocôndrias/metabolismo , Estilbenos/química , Animais , Estabilidade de Medicamentos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Células Endoteliais da Veia Umbilical Humana , Humanos , Sulfeto de Hidrogênio/metabolismo , Indóis/síntese química , Indóis/efeitos da radiação , Luz , Células MCF-7 , Camundongos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Neoplasias/metabolismo , Estilbenos/síntese química , Estilbenos/efeitos da radiação
18.
Sensors (Basel) ; 19(3)2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30709046

RESUMO

With the three-dimensional (3D) coordinates of objects captured by a sequence of images taken in different views, object reconstruction is a technique which aims to recover the shape and appearance information of objects. Although great progress in object reconstruction has been made over the past few years, object reconstruction in occlusion situations remains a challenging problem. In this paper, we propose a novel method to reconstruct occluded objects based on synthetic aperture imaging. Unlike most existing methods, which either assume that there is no occlusion in the scene or remove the occlusion from the reconstructed result, our method uses the characteristics of synthetic aperture imaging that can effectively reduce the influence of occlusion to reconstruct the scene with occlusion. The proposed method labels occlusion pixels according to variance and reconstructs the 3D point cloud based on synthetic aperture imaging. Accuracies of the point cloud are tested by calculating the spatial difference between occlusion and non-occlusion conditions. The experiment results show that the proposed method can handle the occluded situation well and demonstrates a promising performance.

19.
Plant Mol Biol ; 99(6): 535-544, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30707394

RESUMO

KEY MESSAGE: In this study, we first linked the signal molecule H2S with cucurbitacin C, which can cause the bitter taste of cucumber leaves and fruit, and specifically discuss its molecular mechanism. Cucurbitacin C (CuC), a triterpenoid secondary metabolite, enhances the resistance of cucumber plants to pathogenic bacteria and insect herbivores, but results in bitter-tasting fruits. CuC can be induced in some varieties of cucumber on exposure to plant stressors. The gasotransmitter hydrogen sulfide (H2S) participates in multiple physiological processes relating to plant stress resistance. This study focused on the effect of H2S on low temperature-induced CuC synthesis in cucumber. The results showed that treatment of cucumber leaves at 4 °C for 12 h enhanced the content and production rate of H2S and increased the expression of genes encoding enzymes involved in H2S generation, Csa2G034800.1 (CsaLCD), Csa1G574800.1 (CsaDES1), and Csa1G574810.1 (CsaDES2). In addition, treatment at 4 °C or with exogenous H2S upregulated the expression of CuC synthetase-encoding genes and the resulting CuC content in cucumber leaves, whereas pretreatment with hypotaurine (HT, a H2S scavenger) before treatment at 4 °C offset these effects. In vitro, H2S could increase the S-sulfhydration level of His-Csa5G156220 and His-Csa5G157230 (both bHLH transcription factors), as well as their binding activity to the promoter of Csa6G088690, which encodes the key synthetase for CuC generation. H2S pretreatment enhanced the cucumber leaves resistance to the Phytophthora melonis. Together, these results demonstrated that H2S acts as a positive regulator of CuC synthesis as a result of the modification of proteins by S-sulfhydration, also providing indirect evidence for the role of H2S in improving the resistance of plants to abiotic stresses and biotic stresses by regulating the synthesis of secondary metabolites.


Assuntos
Temperatura Baixa , Cucumis sativus/metabolismo , Sulfeto de Hidrogênio/metabolismo , Triterpenos/metabolismo , Cucumis sativus/genética , Cucumis sativus/parasitologia , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas/genética , Phytophthora/patogenicidade , Folhas de Planta/metabolismo , Metabolismo Secundário/genética , Estresse Fisiológico
20.
J Cell Mol Med ; 23(3): 2163-2173, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30648791

RESUMO

The abundant and reversible N6-methyladenosine (m6A) RNA modification and its modulators have important roles in regulating various gene expression and biological processes. Here, we demonstrate that fat mass and obesity associated (FTO), as an m6A demethylase, plays a critical anti-tumorigenic role in clear cell renal cell carcinoma (ccRCC). FTO is suppressed in ccRCC tissue. The low expression of FTO in human ccRCC correlates with increased tumour severity and poor patient survival. The Von Hippel-Lindau-deficient cells expressing FTO restores mitochondrial activity, induces oxidative stress and ROS production and shows impaired tumour growth, through increasing expression of PGC-1α by reducing m6A levels in its mRNA transcripts. Our work demonstrates the functional importance of the m6A methylation and its modulator, and uncovers a critical FTO-PGC-1α axis for developing effective therapeutic strategies in the treatment of ccRCC.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA