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1.
Chemistry ; 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31674063

RESUMO

Optoacoustic imaging exhibits great potential for preclinical research and clinical practice, and designing robust activatable optoacoustic probes for specific diseases is beneficial for its further development. Herein, an activatable probe has been developed for tumor hypoxia imaging. For this probe, indole and quinoline were linked on each side of oxocyclobutenolate core to form an unsymmetrical squaraine. Triarylamine group was incorporated to afford the aggregation enhanced emission (AEE) property. In aqueous media, the squaraine chromophore aggregates into the nanoprobe which specifically responds to nitroreductase and produce strong optoacoustic signals due to its high extinction coefficient, as well as prominent fluorescence emission as a result of its AEE feature. The nanoprobe was used to image tumor metastasis via lymphatic system optoacoustically and fluorescently. Moreover, both the fluorescence signals and three-dimensional multispectral optoacoustic tomography signals from the activated nanoprobe allow us to locate the tumor site and map the metastatic route.

2.
Appl Opt ; 58(27): 7424-7429, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31674391

RESUMO

The photonic crystal fiber (PCF) with better thermal stability and polarization-maintaining performance is applied to the resonant fiber optic gyroscope (RFOG). A hybrid fiber ring resonator is fabricated using the conventional polarization-maintaining fiber (PMF) and PCF with close mode field diameters (MFDs) to reduce MFD-mismatch-induced splicing loss. Furthermore, the temperature-dependent birefringence coefficients of the PMF and the PCF are measured to differ almost four times in absolute value and be opposite in sign. The polarization stability of the hybrid PCF-PMF ring resonator is improved by a factor of 7 compared with the PMF ring resonator with the same length of PMF. The RFOG equipped with this hybrid PCF-PMF ring resonator achieves a bias stability of 1.67°/h.

3.
Int J Mol Sci ; 20(21)2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31671600

RESUMO

Double-spikes Phalaenopsis orchids have greater market value than those with single-spike. In this study, a gene designated as Spike Activator 1 (SPK1), which encodes a basic helix-loop-helix (bHLH) transcription factor, was isolated and characterized from Phalaenopsis aphrodite (moth orchid). SPK1 was highly expressed in the meristematic tissues. In the axillary bud, SPK1 was highly upregulated by a moderately low temperature of 20 °C but downregulated by a spike inhibition temperature of 30 °C. SPK1 protein is localized in the nucleus. Another bHLH, bHLH35, which is also highly expressed in young tissues in the same way as SPK1 was also identified. In contrast to SPK1, bHLH35 transcripts are downregulated at 20 °C but upregulated at 30 °C. Bimolecular florescence complementation assay and yeast two-hybrid assays indicated that SPK1 interacts with bHLH35 and forms a heterodimer. Virus-induced gene silencing (VIGS) showed that 7 out of 15 vector control plants produced double spikes but that only 1 out of 15 VIGS-spk1 plants produced double spikes. RT-qPCR results indicated that VIGS-spk1 downregulated gene expression levels of SPK1, FT, CYCB, and EXPA8. Overall, we propose that SPK1 plays an essential role in early axillary bud development and spike initiation of P. aphrodite.

4.
J Environ Manage ; 253: 109683, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31666210

RESUMO

This study analyzed the seasonal variations and the spatial distributions of total mercury (THg), inorganic divalent mercury (IHg), and methylmercury (MeHg) in sediments of river mouth (RM), main channel (MC), and entrance (E) of the Port of Kaohsiung, Taiwan. The THg, IHg, and MeHg concentrations were, respectively, 198-9130, 2.6-3164, and <0.3-42.6 µg/kg in the wet season and 362-2264, 11.0-790, and 3.3-65.6 µg/kg in the dry season. As for seasonal variations, the concentrations of THg and IHg for RM sediment were higher in the wet season than in the dry season, whereas for MC and E was converse. Generally, MeHg in sediment was higher in the dry season than in the wet season. THg and IHg were mainly transported from the river, whereas MeHg was generated by onsite microbes transforming the local available IHg. Results indicated that the formation of MeHg in sediment may be mainly influenced by the concentration of IHg and seasonal variations.

5.
J Cell Mol Med ; 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31578820

RESUMO

SARI (suppressor of AP-1, regulated by IFN) impaired tumour growth by promoting apoptosis and inhibiting cell proliferation and tumour angiogenesis in various cancers. However, the role of SARI in regulating tumour-associated inflammation microenvironment is still elusive. In our study, the colitis-dependent and -independent primary model were established in SARI deficiency mice and immuno-reconstructive mice to investigate the functional role of SARI in regulating tumour-associated inflammation microenvironment and primary colon cancer formation. The results have shown that SARI deficiency promotes colitis-associated cancer (CAC) development only in the presence of colon inflammation. SARI inhibited tumour-associated macrophages (TAM) infiltration in colon tissues, and SARI deficiency in bone marrow cells has no observed role in the promotion of intestinal tumorigenesis. Mechanism investigations indicated that SARI down-regulates p-STAT1 and STAT1 expression in colon cancer cells, following inhibition of MCP-1/CCR2 axis activation during CAC development. Inverse correlations between SARI expression and macrophage infiltration, MCP-1 expression and p-STAT1 expression were also demonstrated in colon malignant tissues. Collectively, our results prove the inhibition role of SARI in colon cancer formation through regulating TAM infiltration.

6.
Org Lett ; 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31593479

RESUMO

Described is a method for the transformation of a cyclic vinylogous ester to the corresponding polyarylated product. We found a catalytic system comprising palladium diacetate and tris(1-adamantyl)phosphine is quite effective in promoting a set of controlled cascade arylations. As a result, a range of novel (hetero)aryl-containing scaffolds was synthesized with a high level of efficiency.

7.
J Cell Biol ; 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31594806

RESUMO

Seipin is known for its critical role in controlling lipid droplet (LD) assembly at the LD-forming subdomain of the endoplasmic reticulum (ER). Here, we identified a new function of seipin as a negative regulator for sphingolipid production. We show that yeast cells lacking seipin displayed altered sensitivity to sphingolipid inhibitors, accumulated sphingoid precursors and intermediates, and increased serine palmitoyltransferase (SPT) and fatty acid (FA) elongase activities. Seipin associated with SPT and FA elongase, and the interaction was reduced by inhibitors for sphingolipid synthesis in a concentration-dependent manner. We further show that the interactions of seipin with SPT and FA elongase occurred at ER-LD contacts and were likely regulated differentially. Further evidence indicated that LD biogenesis was intact when SPT activity was blocked, whereas excess sphingoid intermediates may affect LD morphology. Expression of human seipin rescued the altered sphingolipids in yeast seipin mutants, suggesting that the negative regulation of sphingolipid synthesis by seipin is likely an evolutionarily conserved process.

8.
Environ Toxicol ; 2019 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-31587482

RESUMO

Benzyl isothiocyanate (BITC), a bioactive natural product present in cruciferous vegetables, has been proved to prevent cancer progression through various mechanisms. In our previous report, we proved that BITC exhibits antitumor effects in bladder cancer by suppressing IGF1R, FGFR3, and mTOR, which is mediated by miR-99a expression. In this study, we identified the signal pathway involved in regulating miR-99a expression after BITC exposure in bladder cancer. Treatment with different BITC concentrations resulted in induction of miR-99a expression in bladder cancer cell lines. Activation of extracellular signal-regulated protein kinase (ERK) and c-jun N-terminal kinase was observed in bladder cancer after BITC treatment for 24 hours. Interestingly, by using a chemical inhibitor of candidate pathways, we found that only the ERK signal pathway is required for miR-99a expression. Furthermore, we evaluated the transcription factor that may contribute to miR-99a expression in response to BITC treatment. The results indicated that c-Jun/AP-1 was activated after BITC treatment. Moreover, we confirmed c-Jun/AP-1 activation through immunofluorescence and the luciferase reporter assay. The results showed that BITC treatment markedly improved nuclear translocation of c-Jun/AP-1 and luciferase activity dose dependently. Finally, pretreatment with the ERK inhibitor U0126 diminished c-Jun phosphorylation and transcriptional activation, suggesting that BITC elicits ERK/c-Jun signal transduction, which is responsible for miR-99a expression in bladder cancer. The present work identifies the mechanism involved in upregulation miR-99a after BITC treatment, which provides an explanation for BITC biological function in our previous work.

9.
J Formos Med Assoc ; 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31653576

RESUMO

BACKGROUND/PURPOSE: Oral submucous fibrosis (OSF) represents a precancerous lesion of oral mucosa that may progress into oral cancer and its major etiological factor is areca nut chewing. Carboxyl-terminus of Hsp70-interacting protein (CHIP) functions as an ubiquitin E3 ligase and is associated with fibrosis diseases. In the current study, we sought to investigate whether CHIP participated in the areca nut-mediated OSF development. METHODS: The mRNA expression of CHIP in arecoline-stimulated buccal mucosal fibroblasts (BMFs) and OSF tissues was determined by qRT-PCR. Collagen gel contraction, migration and invasion assays were carried out to evaluate the myofibroblast activation. The protein expression levels of α-SMA and transglutaminase 2 (TGM2) were assessed by Western blot. RESULTS: The expression level of CHIP was reduced in BMFs following arecoline treatment in a dose-dependent manner, which was consistent with the observation of lower CHIP expression in OSF specimen compared to the normal counterparts. Ectopic expression of CHIP mitigated the myofibroblast activities, including elevated collagen gel contractility and cell motility. In addition, we showed that overexpression of CHIP downregulated the α-SMA and TGM-2 expression, which may lead to less fibrosis alteration. CONCLUSION: CHIP may not only function as a key regulator of protein quality control but also a critical deciding factor to oral fibrogenesis. Our findings suggested that CHIP possesses the anti-fibrotic effect, which may be mediated by TGM2 regulation. Restoration of CHIP could be a therapeutic direction to help OSF patients.

10.
J Card Surg ; 2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31654595

RESUMO

BACKGROUND: The management strategy for secondary mitral regurgitation (MR) during aortic valve surgery for aortic regurgitations (ARs) remains controversial. This study aimed to compare the outcomes between mitral valve annuloplasty (MVP) and no intervention for managing 2+ or 3+ MR among severe patients with AR. METHODS: Eighty-seven eligible patients with complete echocardiographic follow-up were included, with 51 patients in the MVP group and 36 in the No-MVP group. The MVP group had a larger left atrial (LA) diameter (44.2 ± 6.6 vs 49.4 ± 7.6 mm; P = .001) and a higher proportion of 3+ MR (33.3% vs 76.5%; P < .001) than the No-MVP group. After 1:1 propensity-score matching, the patients treated with and without MVP were balanced on 14 preoperative characteristics. RESULTS: There was one in-hospital death in each group. In the propensity-score matched cohort, there was no statistically significant difference between the two groups in the cumulative incidence of residual 2+ MR during a follow-up of 26.4 ± 14.8 months (P = .64). The No-MVP group was associated with a more significant change in the left ventricular end-diastolic dimension (18.1 ± 7.9 vs 13.7 ± 8.7 mm; P = .02), while the changes in the LA diameter, left ventricular end-systolic dimension, and left ventricular ejection fraction were similar between the two groups. CONCLUSIONS: The severity of MR and the LA size may impact surgeons' decisions. MVP does not seem to add extra benefits to the outcomes, and it may be associated with worse left ventricular remodeling.

12.
Int J Nanomedicine ; 14: 7891-7901, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31632006

RESUMO

Purpose: The improvement of postoperative pain control plays an important role in recovery outcomes and patient satisfaction. Multilamellar vesicles ropivacaine, MVR, is being developed to sustain the release of ropivacaine in situ while maintaining the local concentration of ropivacaine within the therapeutic window. Methods: These studies summarized the processes of MVR formulation development and the evaluation of its releasing profile in vitro and the pharmacokinetics and anesthetic effect in vivo. Results: The MVR demonstrates a sustained-release profile in an in vitro serum environment model after 24 hrs of incubation which translates in the in vivo rat pharmacokinetic profile of ropivacaine as a prolonged half-life that is 10-fold longer in duration than plain ropivacaine solution. The anesthetic effect of single-dose MVR is apparent by providing a prolonged analgesia effect compared to plain ropivacaine solution in an in vivo guinea pig pin-prick wheal model after a single intracutaneous injection. From a safety evaluation, MVR is well tolerated after a subcutaneously injection at a dose level of 20 mg/kg in rats, with no observable changes in clinical observation, body weight, organ weight, hematology and serum chemistry analysis. Conclusion: These results suggest that single administration of MVR is a promising candidate in postoperative pain management.

13.
Arch Toxicol ; 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31612242

RESUMO

Aflatoxin B1 (AFB1), a food contaminant derived from Aspergillus fungi, has been reported to cause hepatic immunotoxicity via inflammatory infiltration and cytokines release. As a pro-inflammatory factor, cyclooxygenase-2 (COX-2) is widely involved in liver inflammation induced by xenobiotics. However, the mechanism by which AFB1-induced COX-2 regulates liver inflammatory injury via hepatocytes-Kupffer cells (KCs) crosstalk remains unclear and requires further elucidation. Here, we established a COX-2 upregulated model with AFB1 treatment in vivo (C57BL/6 mice, 1 mg/kg body weight, i.g, 4 weeks) and in vitro (human liver HepaRG cells, 1 µM for 24 h). In vivo, AFB1-treated mice exhibited NLRP3 inflammasome activation, inflammatory infiltration, and increased recruitment of KCs. In vitro, dephosphorylated COX-2 by protein phosphatase 2A (PP2A)-B55δ promoted NLRP3 inflammasome activation, including mitochondrial translocation of NLRP3, caspase 1 cleavage, and IL-1ß release. Moreover, phosphorylated COX-2 at serine 601 (p-COX-2Ser601) underwent endoplasmic reticulum (ER) retention for proteasome degradation. Furthermore, pyroptosis and inflammatory response induced by AFB1 were relieved with COX-2 genetic (siPTGS2) intervention or pharmaceutic (celecoxib, 30 mg/kg body weight, i.g, 4 weeks) inhibition of COX-2 via NLRP3 inflammasome suppression in vivo and in vitro. Ex vivo, in a co-culture system with murine primary hepatocytes and KCs, activated KCs induced by damaged signals from pyroptotic hepatocytes, formed a feedback loop to amplify NLRP3-dependent pyroptosis of hepatocytes via pro-inflammatory signaling, leading to liver inflammatory injury. Taken together, our data suggest a novel mechanism that protein quality control of COX-2 determines the intracellular distribution and activation of NLRP3 inflammasome, which promotes liver inflammatory injury via hepatocytes-KCs crosstalk.

14.
Artigo em Inglês | MEDLINE | ID: mdl-31615196

RESUMO

BACKGROUND: A combination of physical and cognitive training appears to be the effective intervention to improve cognitive function in older adults with mild cognitive impairment (MCI). Computing technology such as virtual reality (VR) may have the potential to assist rehabilitation in shaping brain health. However, little is known about the potential of VR-based physical and cognitive training designed as an intervention for cognition and brain activation in elderly patients with MCI. Moreover, whether a VR program designed around functional tasks can improve their instrumental activities of daily living (IADL) requires further investigation. AIM: This study investigated the effects of 12 weeks of VR-based physical and cognitive training on cognitive function, brain activation and IADL and compared the VR intervention with combined physical and cognitive training. DESIGN: A single-blinded randomized controlled trial. SETTING: Communities and day care centers in Taipei, Taiwan. POPULATION: Older adults with mild cognitive impairment. METHODS: Thirty-four community-dwelling older adults with MCI were randomized into either a VR-based physical and cognitive training (VR) group or a combined physical and cognitive training (CPC) group for 36 sessions over 12 weeks. Participants were assessed for their cognitive function (global cognition, executive function and verbal memory) and IADL at pre- and postintervention. Changes in prefrontal cortex activation during the global cognition test were also captured by functional near-infrared spectroscopy (NIRS) to identify the potential mediating pathway of the intervention. RESULTS: Both groups showed improved executive function and verbal memory (immediate recall). However, only the VR group showed significant improvements in global cognition(p<0.001), verbal memory (delayed recall, p=0.002), and IADL (p<0.001) after the intervention. The group×time interaction effects further demonstrated that IADL were more significantly improved with VR training than with CPC training (p=0.006). The hemodynamic data revealed decreased activation in prefrontal areas after training (p=0.0015), indicative of increased neural efficiency, in the VR-trained subjects. CONCLUSIONS: VR-based physical and cognitive training improves cognitive function, IADL and neural efficiency in older adults with MCI. CLINICAL REHABILITATION IMPACT: VR training could be implemented for older adults with MCI.

15.
Nat Commun ; 10(1): 4503, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31582801

RESUMO

Mechanosensitive Piezo1 and Piezo2 channels transduce various forms of mechanical forces into cellular signals that play vital roles in many important biological processes in vertebrate organisms. Besides mechanical forces, Piezo1 is selectively activated by micromolar concentrations of the small molecule Yoda1 through an unknown mechanism. Here, using a combination of all-atom molecular dynamics simulations, calcium imaging and electrophysiology, we identify an allosteric Yoda1 binding pocket located in the putative mechanosensory domain, approximately 40 Å away from the central pore. Our simulations further indicate that the presence of the agonist correlates with increased tension-induced motions of the Yoda1-bound subunit. Our results suggest a model wherein Yoda1 acts as a molecular wedge, facilitating force-induced conformational changes, effectively lowering the channel's mechanical threshold for activation. The identification of an allosteric agonist binding site in Piezo1 channels will pave the way for the rational design of future Piezo modulators with clinical value.

16.
Eur J Clin Invest ; : e13179, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31610022

RESUMO

BACKGROUND: Everolimus is an effective immunosuppressant in organ transplantation without impaired renal function. The present study aimed to evaluate the efficacy and safety of everolimus therapy in liver transplant recipients. MATERIALS AND METHODS: A systematic literature search was conducted to identify the eligible studies. The quality of the included studies was assessed. The outcomes of interest were biopsy-proven acute rejection (BPAR), graft loss, death, renal function, and adverse events. RESULTS: Eight trials involving 1,570 participants were included. Compared to the standard exposure to calcineurin inhibitors (CNIs), the incidences of BPAR, graft loss, and death were not increased in the everolimus combined with reduced CNIs group. The renal function was significantly improved after everolimus combined with reduced CNI therapy, and the glomerular filtration rate (GFR) was estimated to be elevated by 5.59 (95% CI: 2.17-9.01, P = 0.001) as compared to the standard exposure to CNIs. The risk of any adverse event was increased by everolimus combined with reduced CNI therapy (RR = 1.22, 95% CI: 1.04-1.42, P = 0.01) as compared to the standard exposure to CNIs. The likelihood of infection was not associated with the regimen. Any publication bias was not identified. CONCLUSIONS: Although everolimus combined with reduced CNI therapy significantly improved the renal function in liver transplant recipients, it did not influence the incidence of BPAR, graft loss, and death. This regimen might be associated with an increased risk of adverse events, which needs to be elucidated further.

17.
Br J Haematol ; 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31610612

RESUMO

Significant phenotypic heterogeneity exists in patients with all subtypes of myeloproliferative neoplasms (MPN), including essential thrombocythaemia (ET). Single-cell RNA sequencing (scRNA-Seq) holds the promise of unravelling the biology of MPN at an unprecedented level of resolution. Herein we employed this approach to dissect the transcriptomes in the CD34+ cells from the peripheral blood of seven previously untreated ET patients and one healthy adult. The mutational profiles in these patients were as follows: JAK2 V617F in two, CALR in three (one type I and two type II) and triple-negative (TN) in two. Our results reveal substantial heterogeneity within this enrolled cohort of patients. Activation of JAK/STAT signalling was recognized in discrepant progenitor lineages among different samples. Significantly disparate molecular profiling was identified in the comparison between ET patients and the control, between patients with different driver mutations (JAK2 V617F and CALR exon 9 indel), and even between patients harbouring the same driver. Intra-individual clonal diversity was also found in the CD34+ progenitor population of a patient, possibly indicating the presence of multiple clones in this case. Estimation of subpopulation size based on cellular immunophenotyping suggested differentiation bias in all analysed samples. Furthermore, combining the transcriptomic information with data from targeted sequencing enabled us to unravel key somatic mutations that are molecularly relevant. To conclude, we demonstrated that scRNA-Seq extended our knowledge of clonal diversity and inter-individual heterogeneity in patients with ET. The obtained information could potentially leapfrog our efforts in the elucidation of the pathogenesis of the disease.

18.
Diabetes Ther ; 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31659627

RESUMO

INTRODUCTION: The aim of this study was to objectively analyze the correlation between dietary components and blood glucose variation by means of continuous glucose monitoring (CGM). METHODS: Patients with type 1 diabetes mellitus (T1DM) who received CGM to manage their blood glucose levels were enrolled into the study, and the components of their total caloric intake were analyzed. Glycemic variation parameters were calculated, and dietary components, including percentages of carbohydrate, protein and fat in the total dietary intake, were analyzed by a dietitian. The interaction between parameters of glycemic variability and dietary components was analyzed. RESULTS: Sixty-one patients with T1DM (33 females, 28 males) were enrolled. The mean age of the participants was 34.7 years, and the average duration of diabetes was 14 years. Glycated hemoglobin before CGM was 8.54%. Participants with a carbohydrate intake that accounted for < 50% of their total caloric intake had a longer DM duration and a higher protein and fat intake than did those with a carbohydrate intake that accounted for ≥ 50% of total caloric intake, but there was no between-group difference in total caloric intake per day. The group with a carbohydrate intake that accounted for < 50% of their total caloric intake also had lower nocturnal continuous overlapping net glycemic action (CONGA) 1, - 2 and - 4 values. The percentage of protein intake had a slightly negative correlation with mean amplitude of glycemic excursions (MAGE) (r = - 0.286, p < 0.05) and a moderately negative correlation with coefficient of variation (CV) (r = 0.289, p < 0.05). One additional percentage of protein calories of total calories per day decreased the MAGE to 4.25 mg/dL and CV to 0.012 (p < 0.05). The optimal dietary protein percentage for MAGE < 140 mg/dL was 15.13%. The performance of predictive models revealed the beneficial effect of adequate carbohydrate intake on glucose variation when combined with protein consumption. CONCLUSIONS: Adequate carbohydrate consumption-but not more than half the daily total calories-combined with protein calories that amount to approximately 15% of the daily caloric intake is important for glucose stability and beneficial for patients with T1DM.

19.
Biol Lett ; 15(10): 20190503, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31662063

RESUMO

A recurring theme in the evolution of tetrapods is the shift from sprawling posture with laterally orientated limbs to erect posture with the limbs extending below the body. However, in order to invade particular locomotor niches, some tetrapods secondarily evolved a sprawled posture. This includes moles, some of the most specialized digging tetrapods. Although their forelimb anatomy and posture facilitates burrowing, moles also walk long distances to forage for and transport food. Here, we use X-ray Reconstruction Of Moving Morphology (XROMM) to determine if the mole humerus rotates around its long axis during walking, as it does when moles burrow and echidnas walk, or alternatively protracts and retracts at the shoulder in the horizontal plane as seen in sprawling reptiles. Our results reject both hypotheses and demonstrate that forelimb kinematics during mole walking are unusual among those described for tetrapods. The humerus is retracted and protracted in the parasagittal plane above, rather than below the shoulder joint and the 'false thumb', a sesamoid bone (os falciforme), supports body weight during the stance phase, which is relatively short. Our findings broaden our understanding of the diversity of tetrapod limb posture and locomotor evolution, demonstrate the importance of X-ray-based techniques for revealing hidden kinematics and highlight the importance of examining locomotor function at the level of individual joint mobility.

20.
Sci Rep ; 9(1): 15074, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31636336

RESUMO

One critical challenge of exploring flora phenology is on characterizing ecosystem phenological diversity (EPD), and thus how EPD's performance is influenced by climate changes has also been an open macro-ecological question. To fill these two gaps, we proposed an innovative method for reflecting EPD, by taking the advantage of the often-classified inverse factor of spatial resolution discrepancy between the used remote sensing datasets of vegetation phenological dates (green-up and brown-up) and snow cover phenological dates (SPDs) (onset and end) around the Arctic, and further, we examined the cross response/feedbacks of the two kinds of EPDs to the two categories of SPDs. We found that the circumpolar green-up and brown-up EPDs both were shrinking, driven more by the delaying of the onset SPDs than the advancing of the end SPDs; North America and North Eurasia performed with inconsistent EPD response/feedbacks to the related SPD anomalies; and further, the EPD-SPD response/feedbacks in some locations exhibited the time-lag effect, e.g., the green-up EPDs made the strongest response to the onset SPDs of two years earlier. Overall, the validated method and the new findings are of implications for improving the phenology modules in Earth system models, and the contributions of the present study have enlightening significance for kicking off the new EPD branch in macrosystem phenological ecology.

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