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1.
Opt Lett ; 45(3): 694-697, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32004287

RESUMO

Retinal optical coherence tomography (OCT) and OCT angiography (OCTA) suffer from the degeneration of image quality due to speckle noise and bulk-motion noise, respectively. Because the cross-sectional retina has distinct features in OCT and OCTA B-scans, existing digital filters that can denoise OCT efficiently are unable to handle the bulk-motion noise in OCTA. In this Letter, we propose a universal digital filtering approach that is capable of minimizing both types of noise. Considering that the retinal capillaries in OCTA are hard to differentiate in B-scans while having distinct curvilinear structures in 3D volumes, we decompose the volumetric OCT and OCTA data with 3D shearlets, thus efficiently separating the retinal tissue and vessels from the noise in this transform domain. Compared with wavelets and curvelets, the shearlets provide better representation of the layer edges in OCT and the vasculature in OCTA. Qualitative and quantitative results show the proposed method outperforms the state-of-the-art OCT and OCTA denoising methods. Also, the superiority of 3D denoising is demonstrated by comparing the 3D shearlet filtering with its 2D counterpart.

2.
J Endocrinol ; 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32027602

RESUMO

Remodeling of energy-storing white fat into energy-consuming beige fat has led to a promising new approach to alleviate adiposity. Several studies have shown adipokines can induce white adipose tissues (WAT) beiging through autocrine or paracrine actions. Betatrophin, a novel adipokine, has been linked to energy expenditure and lipolysis but not clearly clarified. Here, we using high-fat diet induced obesity to determine how betatrophin modulate beiging and adiposity. We found that betatrophin-knockdown mice displayed less white fat mass and decreased plasma TG and NEFA levels. Consistently, inhibition of betatrophin leads to the phenotype change of adipocytes characterized by increased mitochondria contents, beige adipocytes and mitochondrial biogenesis-specific markers both in vivo and in vitro. Notably, blocking AMP-activated protein kinase (AMPK) signaling pathway is able to abolish enhanced beige-like characteristics in betatrophin-knockdown adipocytes. Collectively, down-regulation of betatrophin induces beiging in white adipocytes through activation of AMPK signaling pathway. These processes suggest betatrophin as a latent therapeutic target for obesity.

3.
Clin Cancer Res ; 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001481

RESUMO

On March 8, 2019, the FDA granted accelerated approval to atezolizumab in combination with paclitaxel protein-bound for the treatment of adult patients with unresectable locally advanced or metastatic triple-negative breast cancer (TNBC) whose tumors express PD-L1 (PD-L1 stained tumor-infiltrating immune cells [IC] of any intensity covering ≥ 1% of the tumor area), as determined by an FDA-approved test. Approval was based on data from IMpassion130, which randomized patients to receive atezolizumab or placebo in combination with paclitaxel-protein bound. Investigator-assessed progression-free survival (PFS) in the intent-to-treat (ITT) and PD-L1-positive populations were co-primary endpoints. After 13 months median follow-up, the estimated median PFS in the PD-L1-positive population was 7.4 months in the atezolizumab arm and 4.8 months in the placebo arm (HR 0.60, 95% CI 0.48-0.77). Overall survival results were immature with 43% deaths in the ITT population, representing 59% of the OS events required to perform the final OS analysis. Adverse reactions occurring in >20% of patients receiving atezolizumab with paclitaxel-protein bound were alopecia, peripheral neuropathies, fatigue, nausea, diarrhea, anemia, constipation, cough, headache, neutropenia, vomiting, and decreased appetite. Accelerated approval was appropriate taking into account the unmet medical need along with the immaturity of the OS results and potential for PFS in the PD-L1 expressing population to predict clinical benefit.

4.
Exp Cell Res ; : 111897, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32035951

RESUMO

Mucins are major macromolecular components of lung mucus that are mainly responsible for the viscoelastic property of mucus. MUC5AC is a major mucin glycoprotein that is hypersecreted in asthmatic individuals. Vascular endothelial growth factor (VEGF) has been implicated in inflammatory and airway blood vessel remodeling in asthmatics. Our previous studies indicate that VEGF upregulates MUC5AC expression by interacting with VEGF receptor 2 (VEGFR2). It has been shown that dexamethasone (Dex) downregulates MUC5AC expression; however, the underlying mechanisms have not been completely elucidated. Therefore, we sought to investigate the effect of Dex on MUC5AC expression induced by VEGF and study the underlying mechanisms. We tested the effects of Dex on VEGFR2 and RhoA activation, caveolin-1 expression, and the association of caveolin-1 and VEGFR2 in primary bronchial epithelial cells. Dex downregulated MUC5AC mRNA and protein levels in a dose- and time-dependent manner, and suppressed the activation of VEGFR2 and RhoA induced by VEGF. Additionally, Dex upregulated caveolin-1 protein levels in a dose- and time-dependent manner. Furthermore, phospho-VEGFR2 expression was decreased through overexpression of caveolin-1 and increased after caveolin-1 knockdown. Dex treatment attenuated the VEGF-decreased association of caveolin-1 and VEGFR2. Collectively, our findings suggest that Dex downregulates VEGF-induced MUC5AC expression by inactivating VEGFR2 and RhoA. Furthermore, decreased MUC5AC expression by Dex was related to the increased association of caveolin-1 with VEGFR2. Further studies characterizing these mechanisms are required to facilitate the development of improved treatment strategies for asthma.

5.
Ecotoxicol Environ Saf ; 192: 110291, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32061984

RESUMO

Partially substituting chemical fertilizer with organic manure can aid in the disposal of agricultural wastes via recycling into agricultural land, reduce chemical fertilizer application, and influence nitrogen (N) transformation. However, relatively few studies have investigated the association between soil physicochemical properties, denitrifier communities and N2O emission after short-term substitution of organic manure in vegetable fields. We conducted a short-term vegetable field experiment which included one control treatment (CT, no fertilizer) and three fertilization treatments containing equal amount of total N, phosphorus and potassium (CF, chemical fertilizer only; CMR, chemical fertilizer plus mushroom residue; COM, chemical fertilizer plus cattle manure). The results showed that partial substitution of chemical fertilizer with organic manure greatly increased cumulative N2O emissions, N2O emission factors and yield-scaled N2O emissions by 122-203%, 238-600% and 128-181%, respectively. Compared with the CF treatment, short-term substitution with organic manure reduced the abundance of nirS- and nosZ-type denitrifiers, and increased that of nirK-type denitrifiers. Modeling indicated that nirS abundance, together with soil available N, NIR activity, nirK abundance, SOC, NH4+, and NO3- were the primary factors associated with cumulative N2O emissions. The denitrifier community composition of the CF- treated soil was separated from that of soils treated with CMR and COM, and was primarily influenced by soil NH4+ concentration. NIR activity showed a significant correlation with denitrifier community composition. Overall, short-term substitution of chemical fertilizer with cattle manure (lower C/N ratio) reduced the abundance of nirS- and nosZ-type denitrifiers, but stimulated N2O emission.

6.
Artigo em Inglês | MEDLINE | ID: mdl-32078542

RESUMO

Precise characterization and analysis of corneal nerve fiber tortuosity are of great importance in facilitating examination and diagnosis of many eye-related diseases. In this paper we propose a fully automated method for image-level tortuosity estimation, comprising image enhancement, exponential curvature estimation, and tortuosity level classification. The image enhancement component is based on an extended Retinex model, which not only corrects imbalanced illumination and improves image contrast in an image, but also models noise explicitly to aid removal of imaging noise. Afterwards, we take advantage of exponential curvature estimation in the 3D space of positions and orientations to directly measure curvature based on the enhanced images, rather than relying on the explicit segmentation and skeletonization steps in a conventional pipeline usually with accumulated pre-processing errors. The proposed method has been applied over two corneal nerve microscopy datasets for the estimation of a tortuosity level for each image. The experimental results show that it performs better than several selected state-of-the-art methods. Furthermore, we have performed manual gradings at tortuosity level of four hundred and three corneal nerve microscopic images, and this dataset has been released for public access to facilitate other researchers in the community in carrying out further research on the same and related topics.

7.
J Environ Sci (China) ; 90: 146-156, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081311

RESUMO

Soil dissolved organic matter (DOM) plays an essential role in the Three Gorges Reservoir (TGR) as a linkage between terrestrial and aquatic systems. In particular, the reducing capacities of soil DOM influence the geochemistry of contaminants such as mercury (Hg). However, few studies have investigated the molecular information of soil DOM and its relationship with relevant geochemical reactivities, including redox properties. We collected samples from eight sites in the TGR areas and studied the link between the molecular characteristics of DOM and their electron donation capacities (EDCs) toward Hg(II). The average kinetic rate and EDC of soil DOM in TGR areas were (0.004 ± 0.001) hr-1 and (2.88 ± 1.39) nmol e-/mg DOMbulk, respectively. Results suggest that higher EDCs and relatively rapid kinetics were related to the greater electron donating components of lignin-derived and perhaps pyrogenic DOM, which are the aromatic constituents that influenced the reducing capacities of DOM in the present study. Molecular details revealed that even the typical autochthonous markers are important for the EDCs of DOM as well, in contrast to what is generally assumed. More studies identifying specific DOM molecular components involved in the abiotic reduction of Hg(II) are required to further understand the relations between DOM sources and their redox roles in the environmental fate of contaminants.

8.
Int J Mol Sci ; 21(4)2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32069992

RESUMO

In recent years, Na/K-ATPase signaling has been implicated in different physiological and pathophysiological conditions, including cardiac hypertrophy and uremic cardiomyopathy. Cardiotonic steroids (CTS), specific ligands of Na/K-ATPase, regulate its enzymatic activity (at higher concentrations) and signaling function (at lower concentrations without significantly affecting its enzymatic activity) and increase reactive oxygen species (ROS) generation. On the other hand, an increase in ROS alone also regulates the Na/K-ATPase enzymatic activity and signaling function. We termed this phenomenon the Na/K-ATPase-mediated oxidant-amplification loop, in which oxidative stress regulates both the Na/K-ATPase activity and signaling. Most recently, we also demonstrated that this amplification loop is involved in the development of uremic cardiomyopathy. This review aims to evaluate the redox-sensitive Na/K-ATPase-mediated oxidant amplification loop and uremic cardiomyopathy.

9.
Chem Commun (Camb) ; 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32073080

RESUMO

Direct C-H functionalization of aryl ethers remains challenging owing to their low reactivity and selectivity. Herein, a novel strategy for nondirected C-H alkenylation of aryl ethers promoted by a dual ligand catalyst was demonstrated. This catalytic system readily achieved the highly efficient alkenylation of alkyl aryl ethers (anisole, phenetole, n-propyl phenyl ether, n-butyl phenyl ether and benzyl phenyl ether), cyclic aryl ethers (1,4-benzodioxan, 2,3-dihydrobenzofuran, dibenzofuran), and diphenyl oxides. Moreover, the proposed methodology was successfully employed for the late-stage modification of complex drugs containing the aryl ether motif. Interestingly, the compounds developed herein displayed fluorescent properties, which would facilitate their biological applications.

10.
Adv Exp Med Biol ; 1213: 149-163, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32030669

RESUMO

The skin is the largest organ of our body. Skin disease abnormalities which occur within the skin layers are difficult to examine visually and often require biopsies to make a confirmation on a suspected condition. Such invasive methods are not well-accepted by children and women due to the possibility of scarring. Optical coherence tomography (OCT) is a non-invasive technique enabling in vivo examination of sub-surface skin tissue without the need for excision of tissue. However, one of the challenges in OCT imaging is the interpretation and analysis of OCT images. In this review, we discuss the various methodologies in skin layer segmentation and how it could potentially improve the management of skin diseases. We also present a review of works which use advanced machine learning techniques to achieve layers segmentation and detection of skin diseases. Lastly, current challenges in analysis and applications are also discussed.


Assuntos
Processamento de Imagem Assistida por Computador , Aprendizado de Máquina , Dermatopatias/diagnóstico por imagem , Pele/diagnóstico por imagem , Tomografia de Coerência Óptica , Humanos
11.
Nat Commun ; 11(1): 497, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31980641

RESUMO

Efficient conversion of carbon dioxide (CO2) into value-added products is essential for clean energy research. Design of stable, selective, and powerful electrocatalysts for CO2 reduction reaction (CO2RR) is highly desirable yet largely unmet. In this work, a series of metalloporphyrin-tetrathiafulvalene based covalent organic frameworks (M-TTCOFs) are designed. Tetrathiafulvalene, serving as electron donator or carrier, can construct an oriented electron transmission pathway with metalloporphyrin. Thus-obtained M-TTCOFs can serve as electrocatalysts with high FECO (91.3%, -0.7 V) and possess high cycling stability (>40 h). In addition, after exfoliation, the FECO value of Co-TTCOF nanosheets (~5 nm) is higher than 90% in a wide potential range from -0.6 to -0.9 V and the maximum FECO can reach up to almost 100% (99.7%, -0.8 V). The electrocatalytic CO2RR mechanisms are discussed and revealed by density functional theory calculations. This work paves a new way in exploring porous crystalline materials in electrocatalytic CO2RR.

12.
Artigo em Inglês | MEDLINE | ID: mdl-31989745

RESUMO

Here, we developed a versatile strategy to covalently connect crystalline covalent organic frameworks (COFs) with semiconductors to create stable organic-inorganic Z-scheme heterojunctions for artificial photosynthesis. A series of COF-semiconductor Z-scheme photocatalysts integrating water oxidation semiconductors (TiO2, Bi2WO6 and α-Fe2O3) with CO2 reduction COFs (COF-316/318) were synthesized and exhibited high photocatalytic CO2-to-CO conversion efficiency (69.67/ 57.1/ 31.43 µmol/g/h for COF-318-TiO2/-Bi2WO6/-α-Fe2O3), with H2O as electron donor in the gas-solid CO2 reduction without additional photosensitizers and sacrificial agents. This is the first report of covalent bonded COF-inorganic semiconductor Z-scheme applied for artificial photosynthesis. Experiments and density functional theory confirmed the efficient electron transfer from semiconductors to COFs by covalent coupling, resulting in the electrons accumulated in cyano/pyridine of COF for CO2 reduction and positive holes leave in semiconductor for H2O oxidation, thus mimicking the natural photosynthesis. This work developed a new method to create covalent bond linked organic-inorganic Z-scheme heterojunction and demonstrated a breakthrough on the field of artificial photosynthesis.

13.
PLoS One ; 15(1): e0228267, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31995608

RESUMO

PURPOSE: To investigate changes in intraocular pressure (IOP) and axial length (AL) on the ascent to high altitude from Beijing to Lhasa. PATIENTS AND METHODS: Twenty volunteers (17 men, 3 women) who had been sent to work in Lhasa, Tibet for more than 6 months were enrolled. One of their journeys from Beijing to Lhasa was chosen as the time for the examination. IOP, AL, corneal curvature (K), and blood pressure (BP) were measured in Beijing (altitude 43 m) and Lhasa (altitude 3658 m). Their first examination was conducted at least 1 day before arriving in Lhasa and the second examination after they had stayed in Lhasa for 7 days. The data from the highland and lowland examinations were analyzed with a paired-sample T test and Pearson's correlation coefficient was calculated for the association between IOP and average BP. RESULTS: The mean IOP was 12.65±2.34 mmHg in Beijing and 14.85±3.1 mmHg in Lhasa. The mean AL was 24.61±1.50mm in Beijing, and 24.98±1.45 mm in Lhasa. The IOP and AL showed a significant elevation in highland compared with lowland (P<0.05). The mean K was 43.58±2.25 D in Beijing and 43.56±2.21 D in Lhasa and no significant difference was found in this study (P>0.05). A positive correlation between variance of IOP and ACD was found (r = 0.475, P<0.05) and no correlation between IOP and average BP was noted. CONCLUSIONS: High altitude may lead to a small but significant change in IOP and axial length. However, the shape of the corneal surface was not influenced by the hypobaric and hypoxic conditions.

14.
J Exp Bot ; 2020 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31925954

RESUMO

The effect of shading during seed development on subsequent germination is largely unknown so far. In this study, two soybean seed production systems, monocropping (MC) and maize-soybean intercropping (IC), were employed. Compared to the MC soybean seeds, which received the normal light spectrum, the developing IC seeds were exposed to shade resulting from the taller neighboring maize plants. The IC seeds germinated faster than did the MC seeds, while there was no significant difference in the seed coat thickness. The soluble pro-anthocyanidin concentration in the IC seed coat was significantly lower than that in the MC seed coat, and the change of concentrations of several types of fatty acids in IC seeds was documented, findings which are consistent with the germination evidence. The expression levels of genes involved in abscisic acid (ABA) biosynthesis were down-regulated in IC seeds, while the transcription levels of the genes related to gibberellin (GA) biosynthesis were up-regulated. Consistently, this was also reflected in decreasing ABA concentration and increasing active GA4 concentration in IC seeds, resulting in an increased GA4/ABA ratio. Altogether, shading in mother plant during seed development promoted subsequent seed germination by mediating the biosynthesis of pro-anthocyanidins, fatty acids and phytohormones.

15.
Artigo em Inglês | MEDLINE | ID: mdl-31961982

RESUMO

A library of symmetrical linear oligothiophene has been prepared employing decarboxylative cross-coupling reaction as the key transformation. We utilized thiophene potassium carboxylate salts as cross-coupling partners without the need of co-catalyst, base, or additives. This method demonstrates complete chemoselectivity and is a comprehensive greener approach compared to the existing methodologies. The modularity of this approach is demonstrated with the preparation of discreet oligothiophenes with up to 10 thiophene repeat units. Symmetrical oligothiophenes represent prototypical organic semiconductors and allow us to spectroscopically assess their response to molecular electrical doping regarding the degree of charge transfer as a function of the chain length. We find evidence that the critical length for integer charge transfer as it is found in the polythiophene limit to be not more than 10 thiophene units, which highlights the potential of long discreet oligothiophenes for their use in organic electronic applications as doped conduction or injection layers.

16.
FASEB J ; 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31950551

RESUMO

Telomerase plays a pivotal role in tumorigenesis by maintaining telomere homeostasis, a hallmark of cancer. However, the mechanisms by which telomerase is reactivated or upregulated during tumorigenesis remain incompletely understood. Here, we report that the Hippo pathway effector Yes-associated protein (YAP) regulates the expression of human telomerase reverse transcriptase (hTERT). Ectopic expression or physiological activation of YAP increases hTERT expression, whereas knockdown of YAP decreases the expression of hTERT. YAP binds to the hTERT promoter through interaction with the TEA domain family transcription factors and activates hTERT transcription. Furthermore, sustained YAP hyperactivation promotes telomerase activity and extends telomere length, with increased hTERT expression. In addition, we show that hTERT expression is positively correlated with YAP activation in human liver cancer tissues. Together, our results demonstrate that YAP promotes hTERT expression, which could contribute to tumor progression.

17.
Artigo em Inglês | MEDLINE | ID: mdl-31923124

RESUMO

STUDY DESIGN: A prospective cohort study. OBJECTIVE: We conducted a prospective cohort study to identify the association between steroids and clinical worsening and compare outcomes between patients with and without preoperative steroid administration. SUMMARY OF BACKGROUND DATA: Patients with SDAVFs often were misdiagnosed and treated with steroids which led to acute worsening. METHODS: Patients with angiographically-confirmed SDAVFs were recruited consecutively between March 2013 and December 2014 in two referral centers. We reviewed the history of all the patients to identify those patients who were treated with steroids prior to exclusion of the fistulas. Modified Aminoff & Logue's scale (mALS) was used to evaluate the spinal cord function at different time points: before and after steroid administration, before operation and at 1-year follow-up. Paired t tests were used to assess the mALS of patients with steroid administration at different time points. Unpaired t tests and Pearson chi-square test were used to assess differences between patients with and without steroid administration. RESULTS: 18 patients with (18.2%) and 81 patients without (81.8%) steroid administration were included in this study. At baseline, there were no difference between both patient groups, in regards to age, gender, duration, location of fistula, treatment and preoperative mALS. However, patients without steroid administration had statistically significant better outcome according to their mALS at 1-year follow-up (P < 0.05). CONCLUSION: Steroid administration can induce acute clinical worsening in patients with SDAVFs that may persist despite successful obliteration of the fistula and should thus be avoided. LEVEL OF EVIDENCE: 3.

18.
Med Sci Monit ; 26: e919667, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31994493

RESUMO

BACKGROUND This study explored relationship between Modic change and spinopelvic parameters in the sagittal plane. MATERIAL AND METHODS We divided 80 patients into 4 groups: 60 subjects diagnosed with Modic changes (MC) were enrolled in the MC groups (MC1, MC2, and MC3) with each MC type consisting of 20 subjects, and 60 healthy subjects were enrolled in the control group. Spinopelvic parameters in the sagittal plane were calculated to assess their associations with MC. Multivariate logistic regression was used to explore possible risk factors for MC. RESULTS PI and LL in the MC groups were significant smaller than in the control group (p<0.05). PI, SS, and PT were significantly correlated with LL with a correlation coefficient of 0.75PI, 0.71SS and 0.69PT (p<0.05). Multivariate logistic regression of the significant variables showed that PI (less than 43.2°) is an independent significant risk factor for MC. ROC analysis showed that moderate diagnostic value was obtained for the significant variable, with an area under the curve (AUC) of 0.80 (p>0.05). CONCLUSIONS We concluded that PI is risk factor for MC, and smaller PI is associated with higher incidence of MC.

19.
Inorg Chem ; 59(1): 687-694, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31820951

RESUMO

The combination of magnetic interaction with high magnetic anisotropy provides a promising way for modulating/fine-tuning molecular magnetic behaviors. Here, we show the building block approach for the synthesis of a family of dilanthanide single-molecule magnets (SMMs) bridged with a cyanometallate starting from a monolanthanide SMM. Contingent on the central para-/diamagnetic [M(CN)6]3- (M = Fe, Co) integrated between two highly anisotropic pentagonal-bipyramid Dy(III) subunits, the remanence of magnetization is OFF/ON below 15 K and they respectively display a record reversal barrier of 659 K among d-f SMMs and 975 K among cyano-bridged SMMs.

20.
Sci China Life Sci ; 63(1): 18-58, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31813094

RESUMO

Reproductive biology is a uniquely important topic since it is about germ cells, which are central for transmitting genetic information from generation to generation. In this review, we discuss recent advances in mammalian germ cell development, including preimplantation development, fetal germ cell development and postnatal development of oocytes and sperm. We also discuss the etiologies of female and male infertility and describe the emerging technologies for studying reproductive biology such as gene editing and single-cell technologies.

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