Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.351
Filtrar
2.
Sci Rep ; 10(1): 1598, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005910

RESUMO

Based on the electrical characteristic detection technology, the quantitative prediction models of sensory score and physical and chemical quality Index (theaflavins, thearubigins, and theabrownins) were established by using the fermented products of Congou black tea as the research object. The variation law of electrical parameters during the process of fermentation and the effects of different standardized pretreatment methods and variable optimization methods on the models were discussed. The results showed that the electrical parameters vary regularly with the test frequency and fermentation time, and the substances that hinder the charge transfer increase gradually during the fermentation process. The Zero-mean normalization (Zscore) preprocessing method had the best noise reduction effect, and the prediction set correlation coefficient (Rp) value of the original data could be increased from 0.172 to 0.842. The mixed variable optimization method (MCUVE-CARS) of Monte Carlo uninformed variable elimination (MC UVE) and competitive adaptive reweighted sampling (CARS) was proved that the characteristic electrical parameters were the loss factor (D) and reactance (X) of the low range. Based on the characteristic variables screened by MCUVE-CARS, the quantitative prediction models for each fermentation quality indicator were established. The Rp values of the sensory score, theaflavin, thearubigin and theabrownins of the predicted models were 0.924, 0.811, 0.85 and 0.938 respectively. The relative percent deviation (RPD) values of the sensory score, theaflavins, thearubigins and theabrownins of the predicted models were 2.593, 1.517, 1,851 and 2.920 respectively, and it showed that these models have good performance and could realize quantitative characterization of key fermentation quality indexes.

3.
Sci Total Environ ; 714: 136856, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-32018988

RESUMO

Bioenergy carbon capture and storage (BECCS) is an effective option for mitigation of greenhouse gas (GHG) emissions. Nevertheless, there is barely serious debate about whether its implementation can possibly jeopardize the global water resources security. Here, we provided an assessment of biomass-based Substitute Natural Gas (BioSNG) production combined with CCS, a promising BECCS technology, in terms of global water resources security, with a focus on the growth of two typical second-generation bioenergy crops: switchgrass and miscanthus. A bottom-up analysis approach was applied in this paper to calculating water consumption for BECCS and estimating water quality deterioration caused by increasing fertilizer and pesticide application. The results indicated that water usage of BECCS was equal to adding 12.86%-16.64% (switchgrass) and 17.59%-26.06% (miscanthus) additional water stress on global available water resources at 2100. Additional N fertilizer application in 2100 would be equal to over 84%, 55% and 42% for both switchgrass and miscanthus under three CCS capture efficiency scenarios, respectively, comparing to such global scale in 2012. Additional phosphate fertilizer adding to global annual available water at 2100 were 0.004-0.008 mg L-1 (switchgrass) and 0.003-0.006 mg L-1 (miscanthus), respectively. The secondary environmental hazards, such as N2O emission, would offset GHG emission mitigation by BECCS. Meanwhile, the enrichment and leaching of pesticide residues increased the risk of groundwater contamination. This study revealed water consumption and contamination issues caused by BECCS cannot be neglected. Thus, additional studies of accurate land-use models in global scale and advanced technology for biofuel extraction are needed in the future.

4.
Sci Rep ; 10(1): 3196, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081960

RESUMO

We selected four Populus euphratica Oliv. forest plots (100 m × 100 m) in the upper reaches of the Tarim River in the Xinjiang Uygur Autonomous Region of China. Each of the four forest plots was chosen to represent a different growth and death stage of P. euphratica forest: juvenile forest, mature forest, dying forest, and dead forest. In each plot, we measured the coordinates, DBH, height, and status of all P. euphratica individuals. We used (1) spatial pattern analysis to explore spatial distribution patterns and associations of live trees and dead trees, (2) a random mortality model to test whether the tree death was random or non-random, and (3) a generalized linear mixed-effect model (GLMM) to analyse factors related to tree survival (or death). In the juvenile plot, live trees were significantly aggregated at all scales (p < 0.05); while in the mature and dying plots, live trees were more aggregated at small scales and randomly distributed at larger scales. Live trees and dead trees showed a significantly positive association at all scales in the juvenile plot (p < 0.05). While in the mature and dying plots, live trees and dead trees only showed a significantly positive association at scales of 0-3 m (p < 0.05). There was significant density-dependent mortality in the juvenile plot; while mortality was spatially random at all scales in the mature and dying plots. The distance from the river showed significantly negative correlations with tree survival (p < 0.01). DBH and height had significantly positive associations with tree survival in the juvenile, mature, and dying plots (p < 0.05). In extreme drought, dying trees appeared to be shape-shifting into more shrub-like forms with clumps of root sprouts replacing the high canopies. The shift under extreme drought stress to more shrub-like forms of P. euphratica may extend their time to wait for a favourable change.

5.
Artigo em Inglês | MEDLINE | ID: mdl-32041406

RESUMO

Quasi-2D Ruddlesden-Popper perovskites exhibit excellent photostability/environmental stability. However, the main drawback is their relatively low photovoltaic properties compared with three-dimensional perovskites. Herein, we demonstrated that chlorine-based additives via adjusting the proportion of PbI2 and PbCl2 in the precursor (BA)2(MA)3Pb4I13 (n = 4) solutions show an optimized device performance of over 15%, and the devices exhibit much improved humidity stability. Upon PbCl2 addition, the quasi-2D perovskites have larger and more compact grains, which result in high quality of films. The photoluminescence gives rise to a much prolonged lifetime under the PbCl2 additive, indicating fewer trap states to reduce the nonradiative recombination. The capacitance characteristics confirm that the PbCl2 additive can largely decrease the trap states in quasi-2D perovskite films. The capacitance-voltage characteristics indicate that using the PbCl2 additive decreases the charge accumulation toward increasing the charge collection in quasi-2D perovskite solar cells. Our work indicates that the addition of PbCl2 is an effective method to improve the device performance by reducing trap states and increasing charge collection toward developing high-performance quasi-2D perovskite devices.

6.
Chemosphere ; 249: 126115, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32045756

RESUMO

The BCR sequential extraction scheme (SES), initially developed for soils and sediments, is frequently adopted to evaluate the environmental risks of municipal solid waste incineration (MSWI) fly ash. Within the procedure, metals are liberated from the matrix hosting them relying on the selectivity of the chosen chemical reagents or operation conditions. However, the effect of the high content of alkaline substances in MSWI fly ash on the selectivity of acetic acid to acid-soluble fraction metals was ignored. In this study, the feasibility of the BCR SES for evaluating MSWI fly ash was assessed by adjusting the acetic acid washing times in the acid-soluble extraction step. The metal fractionation, as well as mineralogy, morphology, and surface chemistry of the residues after three successive acid washing processes, were analyzed. The results reveal that only easily soluble salts, but not hydroxides, are entirely extracted after the first acid washing (pH∼12.0). Importantly, carbonates (generally reported as an indicator of the complete release of acid-soluble metals) are mostly decomposed only after the third acid washing (pH∼3.8). The incomplete dissolution of calcium carbonates in a single-step acid washing may convey misleading results of metal fractionation and underestimates the environmental risk of potentially toxic elements. Therefore, complete removal of carbonates should be employed as the endpoint of the acid-soluble fraction extraction step in the evaluation of MSWI fly ash. This work can help in selecting proper strategies for fly ash management and developing proper sequential extraction schemes for similar high-alkalinity hazardous waste risk assessment.

7.
Neurosci Lett ; 718: 134743, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31917235

RESUMO

White matter injury caused by perinatal hypoxia-ischemia is characterized by myelination disorders; however, its pathophysiological mechanisms are not fully elucidated. The neurofascin 155 (NF155) protein, expressed in oligodendrocytes, is critical for myelination. Previous findings suggest that NF155 participates in the pathological mechanisms of developmental myelination disorders in hypoxic-ischemic cerebral white matter lesions, and it might regulate cytoskeletal changes. Therefore, we hypothesized that increased NF155 expression during the early stages of hypoxic oligodendrocyte injury helps normalize myelin sheath development and consequently improves neural function by repairing paranodal structures of myelin sheaths and regulating cytoskeletal changes. To test this hypothesis, we established a hypoxic-ischemic, mixed neonatal rat forebrain cell culture model. When NF155 expression was upregulated, synergistic effects occurred between this protein and the paranodal proteins CASPR and contactin. In addition, the expression of Rho GTPase family proteins that regulate key cytoskeletal pathways, myelin sheath structures, and functions were restored, and axonal structures acquired a clear and transparent appearance. These results suggest that NF155 may enable myelin sheath repair by repairing paranodal region structures and regulating oligodendrocyte cytoskeletal mechanisms. Overall, the present study provides new insights into the pathogenesis of hypoxic-ischemic cerebral white matter lesions.

8.
ACS Appl Mater Interfaces ; 12(4): 5120-5127, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31902207

RESUMO

These days, organic-inorganic hybrid perovskites (OIHP) and non-fullerene acceptor (NFA) molecules are all at the frontiers of research and development in the domain of photovoltaics. A careful design and use of inorganic transparent metal oxides with wide band gaps as electron and hole transport layers are critically important for highly efficient and stable solar cells. As one of the most favorable electron transport materials, tin oxide (SnO2), which has been frequently utilized in highly efficient OIHP solar cells, is rarely seen in the application of NFA organic bulk heterojunction (BHJ) solar cells. To appropriately tailor an interface of SnO2 and an organic blend, while to make them compatible and useful may offer some opportunities for achieving higher efficiencies and longer lifetimes. In fact, there is still a lack of a method to solve the problem. Herein, a unique way is developed by implementing a surface decoration nanostructure such as low dimensional MAPbI3 perovskite nanowires (PeNWs) at the interface of SnO2 and the organic blend such as PBDB-T-SF:IT-4F. Such an interface functions well for the improvement of photovoltaic performance for the organic solar cell of the structure ITO(glass)/SnO2/PeNWs/PBDB-T-SF:IT-4F/MoO3/Ag. Experimental results indicate that the electron-hole dissociation, charge extraction, and photo-absorption ability of the organic solar cell can be improved significantly. The inside generation of the photocurrent is explored by the magneto-photocurrent method. Finally, the solar cell exhibits more than 80% power conversion efficiencies even after 20 days, which suggests the merits of having both SnO2 and PeNWs in the NFA-based organic solar cell.

9.
J Neurosurg ; : 1-13, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31899875

RESUMO

OBJECTIVE: To date, long noncoding RNAs (lncRNAs) have proven to function as key regulators in tumorigenesis. Among these lncRNAs, MEG3 displays low levels in various neoplasms and tumor cell lines. However, the regulatory mechanism of MEG3 and MIR-376B-3P, one of the microRNAs from downstream gene clusters of the DLK1-MEG3 locus, remains insufficiently defined. METHODS: The authors used quantitative real-time polymerase chain reaction analysis to analyze whether decreased MEG3 and MIR-376B-3P expression levels were associated with the invasiveness of clinical nonfunctioning pituitary adenomas (CNFPAs) in 30 patients. Furthermore, functional experiments unveiled the pathophysiological role of MEG3, MIR-376B-3P, and HMGA2 in pituitary-derived folliculostellate (PDFS) cell lines. Moreover, dual-luciferase reporter assay, Western blot analysis, and immunofluorescence were applied to reveal the correlations among MEG3, MIR-376B-3P, and HMGA2. RESULTS: MEG3 and MIR-376B-3P were decreased in patients with CNFPA, and their transcriptional levels were highly associated with invasive CNFPAs. Moreover, excessive expression of MEG3 and MIR-376B-3P inhibited tumorigenesis and promoted apoptosis in PDFS cells. Importantly, the authors found that MEG3 acted as an enhancer of MIR-376B-3P expression. Furthermore, as a target gene of MIR-376B-3P, HMGA2 served as an oncogene in pituitary adenoma and could be negatively regulated by MEG3 via enriching MIR-376B-3P. CONCLUSIONS: This study offers a novel mechanism of an MEG3/MIR-376B-3P/HMGA2 regulatory network in CNFPAs, which may become a breakthrough for anticancer treatments.

10.
Bone ; 133: 115247, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31968281

RESUMO

Bone mineral density (BMD) is a key indicator for diagnosis and treatment for osteoporosis; the reduction of BMD could increase the risk of osteoporotic fracture. It was very recently found that Piezo1 mediated mechanically evoked responses in bone and further participated in bone formation in mice. Here, we performed cross phenotype meta-analysis for human BMD at lumbar spine (LS), femoral neck (FN), distal radius/forearm (FA) and heel and screened out 14 top SNPs for PIEZO1, these SNPs were overlapped with putative enhancers, DNase-I hypersensitive sites and active promoter flanking regions. We found that the signal of the best SNP rs62048221 was mainly from heel ultrasound estimated BMD (-0.02 SD per T allele, P = 8.50E-09), where calcaneus supported most of the mechanical force of body when standing, walking and doing physical exercises. Each copy of the effect allele T of SNP rs62048221 was associated with a decrease of 0.0035 g/cm2 BMD (P = 4.6E-27, SE = 0.0003) in UK Biobank data within 477,760 samples. SNP rs62048221 was located at the enhancer region (HEDD enhancer ID 2331049) of gene PIEZO1, site-directed ChIP assays in human mesenchymal stem cells (hMSCs) showed significant enrichment of H3K4me1 and H3K27ac in this region, luciferase assays showed that rs62048221 could significantly affect the activity of the enhancer where it resides. Our results first suggested that SNP rs62048221 might mediate the PIEZO1 expression level via modulating the activity of cis-regulatory elements and then further affect the BMD.

11.
J Phys Chem Lett ; 11(1): 1-6, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31794224

RESUMO

This study demonstrates the influence of the orbit-orbit interaction on the photoluminescence quantum efficiency (PLQE) of metal halide perovskite quantum dots (QDs) through the Rashba effect. The orbit-orbit interaction between excitons was characterized by using the minimal excitation intensity required to generate a photoluminescence difference (ΔPL) between linearly and circularly polarized photoexcitations. It was observed that changing the surface functionalization from PFOA-OA to PFSH-OAm and OA can largely increase the minimal excitation intensity for generating ΔPL. This indicates that the orbit-orbit interaction is essentially decreased in CsPbBr1I2 QDs with surface functionalization. Simultaneously, the PLQE is increased from 39% to 59 and 72% in CsPbBr1I2 QDs upon surface functionalization. Furthermore, the PL lifetime is decreased with increasing the PLQE in CsPbBr1I2 QDs upon surface functionalization. This phenomenon implies that decreasing the orbit-orbit interaction can essentially weaken the Rashba effect and consequently reduce the disallowed transitions, leading to an enhancement in the PLQE in perovskite QDs.

12.
Int J Oncol ; 56(1): 151-164, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31814034

RESUMO

Tumour­associated macrophages (TAMs) compose a major component of the tumour microenvironment and form in this microenvironment prior to cancer metastasis. However, the detailed mechanisms of TAM remodelling in the context of bladder cancer have not been clearly defined. The present study collected exosomes from the conditioned medium of human bladder T24 cancer cells. The effects of macrophages treated with exosomes derived from T24 cells on bladder cancer cell migration and invasion were analysed by Transwell assays. The expression levels of endogenous and exosomal microRNA­21 (miR­21) were examined by reverse transcription­quantitative PCR, while the expression level of the target protein was analysed by western blot analysis. Luciferase reporter plasmids and mutants were used to confirm direct targeting. The effects of miR­21 on bladder cancer cell migration and invasion were analysed by Transwell and Matrigel assays following miR­21 transfection. It was identified that exosomes derived from bladder cancer cells polarized THP­1 cell­derived macrophages into the M2 phenotype, and TAM­mediated pro­migratory and pro­invasive activity was determined. Moreover, it was found that miR­21 was highly expressed in exosomes derived from bladder cancer cells as well as in macrophages treated with exosomes. In addition, macrophages transfected with miR­21 exhibited M2 polarization and promoted T24 cell migratory and invasive ability. Mechanistically, exosomal miR­21 derived from bladder cancer cells inhibited phosphatase and tensin homolog activation of the PI3K/AKT signalling pathway in macrophages and enhanced STAT3 expression to promote M2 phenotypic polarization. The present results suggest that exosomal miR­21 can promote cancer progression by polarizing TAMs.

13.
Sci Total Environ ; 703: 135464, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31753505

RESUMO

Phosphoric acid functionalized superparamagnetic iron oxide was synthesized, and different adsorption behavior of TiO2 NPs and titanium ions on it was found. By means of dispersion-corrected density functional theory (DFT-D), the adsorption mechanism of TiO2 NPs and titanium ions on the functionalized sorbents was explored, and the difference in the adsorption behavior was attributed to the different deprotonated forms of phosphates and the competitive adsorption of OH- anion with respect to either TiO2 NPs or aqueous titanium ions. Based on the different adsorption performance of phosphoric acid functionalized sorbents for TiO2 NPs and titanium ions under pH 3, a method by combining magnetic solid phase extraction (MSPE) with inductively coupled plasma mass spectrometry (ICP-MS) was established for the selective quantification of trace TiO2 NPs in environmental water. Under the optimal experimental conditions, the detection limit of TiO2 NPs was 17 ng/L with an enrichment factor of 400. The developed MSPE-ICPMS method was applied to the detection of trace TiO2 NPs in the Yangtze River and the East Lake water. Sub µg/L level of TiO2 NPs was found in the tested water samples, and recoveries of 91-110% and 90-110% were obtained for TiO2 NPs at three concentration levels in spiked water samples, respectively. The developed method exhibited high adsorption capacity and low detection limit for target TiO2 NPs, and was demonstrated with great potential for monitoring TiO2 NPs in the environment.

14.
HLA ; 95(2): 133-134, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31628781

RESUMO

The novel allele HLA-A*33:131 was identified in a Chinese individual using the sequencing-based typing method.

15.
Environ Pollut ; 257: 113499, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31706771

RESUMO

Production of chrysanthemum (Dendranthema grandiflora) in greenhouses often requires intensive pesticide use, which raises serious concerns over food safety and human health. This study investigated uptake, translocation and residue dissipation of typical fungicides (metalaxyl-M and fludioxonil) and insecticides (cyantraniliprole and thiamethoxam) in greenhouse chrysanthemum when applied in soils. Chrysanthemum plants could absorb these pesticides from soils via roots to various degrees, and bioconcentration factors (BCFLS) were positively correlated with lipophilicity (log Kow) of pesticides. Highly lipophilic fludioxonil (log Kow = 4.12) had the greatest BCFLS (2.96 ±â€¯0.41 g g-1), whereas hydrophilic thiamethoxam (log Kow = -0.13) had the lowest (0.09 ±â€¯0.03 g g-1). Translocation factors (TF) from roots to shoots followed the order of TFleaf > TFstem > TFflower. Metalaxyl-M and cyantraniliprole with medium lipophilicity (log Kow of 1.71 and 2.02, respectively) and hydrophilic thiamethoxam showed relatively strong translocation potentials with TF values in the range of 0.29-0.81, 0.36-2.74 and 0.30-1.03, respectively. Dissipation kinetics in chrysanthemum flowers followed the first-order with a half-life of 21.7, 5.5, 10.0 or 8.2 days for metalaxyl-M, fludioxonil, cyantraniliprole and thiamethoxam, respectively. Final residues of these four pesticides, including clothianidin (a primary toxic metabolite of thiamethoxam), in all chrysanthemum flower samples were below the maximum residue limit (MRL) values 21 days after two soil applications each at the recommended dose (i.e., 3.2, 2.1, 4.3 and 4.3 kg ha-1, respectively). However, when doubling the recommended dose, the metabolite clothianidin remained at concentrations greater than the MRL, despite that thiamethoxam concentration was lower than the MRL value. This study provided valuable insights on the uptake and residues of metalaxyl-M, fludioxonil, cyantraniliprole and thiamethoxam (including its metabolite clothianidin) in greenhouse chrysanthemum production, and could help better assess food safety risks of chrysanthemum contamination by parent pesticides and their metabolites.

16.
J Hazard Mater ; 385: 121574, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31732336

RESUMO

As triphenyl phosphate (TPhP) can biodegrade extensively in sediments, researches should further the understanding of the fate and transport of TPhP and its degradation intermediates in the environment. Therefore, the sorption/desorption behaviors of TPhP, diphenyl phosphate (DPhP) and phenyl phosphate (PhP) on sediments were investigated. The kinetic process was well-fitted by pseudo-second-order model, suggesting that chemisorption was involved. And the Langmuir model could describe the sorption isotherms of TPhP and DPhP well except for PhP. The redundancy analysis revealed that the sorption amount had a positive correlation with sediment organic matter, zeta potential and C/H of sediments. Besides the sorption/desorption behaviors were greatly influenced by the physicochemical properties of the sorbates. PhP with high molecular electrostatic potential (0.132 e0) was prone to protonation and formed hydrogen bonds, leading to higher sorption. Furthermore, hydrophobicity, π-π interactions, Lewis acid-base interaction and hydrogen bonding were involved in the sorption process and resulted in nonlinear sorption isotherms. TPhP, DPhP and PhP exhibited apparent desorption hysteresis on the sediments. Sediments with organic matter removed, which have complex pore distributions, exhibited more hysteresis. These results may contribute to the risk assessment and fate modeling of TPhP and its degradation products in sediments.

17.
Gene ; 726: 144169, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31669642

RESUMO

BACKGROUND (OBJECTIVE): In the development of tumor therapy, the role of long non-coding RNA actin filagenin 1 antisense RNA 1 (1ncRNA AFAP1-AS1) is quite significant, but the actual role of AFAP1-AS1 in the treatment of prostate cancer has not been determined. In view of this, the author took AFAP1-AS1 as the research object to design an experimental study, and conducted an in-depth exploration of the pathogenesis of prostate cancer. METHODS: RT-qPCR was used to detect the expression of AFAP1-AS1 and miR-512-3p in prostate cancer tissues and cell lines. Perforation, flow cytometry and CCK-8 were used to detect the effects of cell proliferation, migration and invasion of mir-512-3p and a AFAP1-AS1. And the luciferase reporter gene was used to detect the downstream target gene of AFAP1-AS1, and the expression of CDK4, CDK6 and CCND1 protein was detected by Western blot. RESULTS: AFAP1-AS1 is highly expressed in prostate cancer tissues and cell lines. The expression level of AFAP1-AS1 is correlated with histological grade and distant metastasis. The overall level of patients with high expression of AFAP1-AS1 is low, and their survival rate is relatively low. Silencing AFAP1-AS1 can significantly increase the proliferation and migration of prostate cancer cells. AFAP1-AS1 silencing induces cell cycle arrest at G0/G1 phase. The downstream target of AFAP1-AS1 was mir-512-3p. The role of AFAP1-AS1 in the progression of prostate cancer cells was mediated by mir-512-3p. CONCLUSION: AFAP1-AS1 regulates miR-512-3p, so as to realize the regulation effect on the proliferation, invasion and migration of prostate cancer cells, and thereby promote the occurrence and development of prostate cancer, so as to provide the corresponding program for the treatment of prostate cancer. Abberivation: ADPC, androgen-dependent prostate cancer; CRPC, castrated prostate cancer; RNA1 AFAP1-Asl, Actin fiber-associated protein 1-anti-RNA1; miRNAs, MicroRNAs.


Assuntos
Proliferação de Células/genética , MicroRNAs/genética , Invasividade Neoplásica/genética , Neoplasias da Próstata/genética , RNA Longo não Codificante/genética , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Fase G1/genética , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Masculino , Fase de Repouso do Ciclo Celular/genética , Taxa de Sobrevida
18.
New Phytol ; 225(4): 1455-1460, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31400226

RESUMO

Nitrogen (N) and phosphorus (P) are the two most abundant mineral nutrients used by plants, and are also the mostly widely used fertilizer elements driving crop yield improvement in agricultural production. The coordinated utilization of N and P is essential to maintain optimal plant growth and achieve maximal crop yield. The signaling pathways of N and P are generally studied separately, so our understanding of N-P interactions is very limited. A series of recent studies have revealed the critical components regulating N-P interactions in both Arabidopsis thaliana and rice (Oryza sativa), and have shed light on our in-depth understanding of the network integrating N and P signaling pathways. Here, we summarize recent progress on N-P interaction and propose possible working mechanisms integrating these N-P interactive regulation pathways. We further discuss future work that might reveal the N-P interactive regulation network in plants.

19.
J Cell Biochem ; 121(2): 1250-1259, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31489998

RESUMO

Among the GTPase family members, guanylate-binding protein-1 (GBP-1) is the most thoroughly studied member in a plethora of human cancers. GBP-2, on the other hand, remains limitedly studied. We wonder how GBP-2 participates in colorectal carcinoma (CRC) as well as the paclitaxel (PTX)-resistance of CRC. In this study, the authors are determined to dig into the role that GBP-2 plays in the sensitivity of CRC to PTX, therefore, possibly indicating a promising gene therapy target for CRC. Forced expression of GBP-2 gene was done by plasmid transfection. Reverse transcriptase-polymerase chain reaction and immunoblot were conducted to detect the expression of GBP-2 messenger RNA (mRNA) and protein, respectively. Colony foci formation assay, transwell invasion assay, and flow cytofluorometry were done to determine the proliferation, invasion, and apoptosis of PTX-resistant and PTX-sensitive CRC cell lines, respectively. The level of GBP-2 mRNA and protein in PTX-resistant CRC cell lines was significantly lower than in nonresistant cell lines. Forced exogenous expression of GBP-2 in PTX-resistant CRC cell lines resulted in more sensitivity to PTX because of the demonstration of less cell proliferation, invasion, and more apoptosis. Wnt signaling was suppressed when GBP-2 was upregulated by transfection of GBP-2 overexpression plasmids, and Wnt signaling did not affect GBP-2 expression. GBP-2 upregulation could enhance the killing effect of PTX in both PTX-sensitive CRC cells and PTX-resistant CRC cells by suppressing Wnt signaling.

20.
J Chromatogr A ; 1609: 460477, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31500879

RESUMO

Porous organic frameworks (POFs) are an exciting emerging type of porous organic materials in which molecular building blocks are linked by covalent bonds. POFs usually have high thermal and chemical stability, large surface area, artificially regulated pore size distribution and abundant functional groups, which are considered to be ideal and efficient adsorbent for diverse compounds. They are an excellent alternative for sorbents/coating-based sample pretreatment techniques. In this review, the application of various POFs in trace analysis is discussed in terms of pretreatment techniques, including solid phase extraction, magnetic solid phase extraction, solid phase microextraction, capillary microextraction and stir bar sorptive extraction. The POFs-based sorbents/coatings are reviewed, with the focus on the construction process, comparison among POFs and between POFs and common sorbents, adsorption mechanism for specific analytes and the adsorption performance in trace analysis. Current research status indicate that much effort would be paid on further exploration of the relationship between the special properties of POFs (e.g., crystal form, pore structure) and the adsorption behavior, directional design and synthesis of POFs involved sorbents/coating for trace analysis of organic substances and elemental species, and the development of POFs-involved analytical methodologies for quantification of interest analytes.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA