Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 451
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Neurochem Res ; 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31701381

RESUMO

Transplantation of neural stem cells (NSCs) may be a potential strategy for traumatic brain injury treatment (TBI) due to their intrinsic advantages, such as cell replacement, secretion of neurotrophins and formation of functional synapses with host. However the underlying effects of transplanted NSCs on host micro-environment still need to be further elucidated. In this manuscript the effects of NSCs on release of neurotransmitter, survival of hippocampal neurons, reactivity of astrocytes and recovery of cognitive function after TBI were observed. The NSCs were isolated from cortex of neonatal Sprague-Dawley rat and then transplanted into injured brain regions caused by free-weight drop. The proliferation of astrocytes around injured sites were examined by GFAP immunofluorescent staining on 3, 7, 14 days after injury. The survival of neurons at CA1 regions of hippocampus toward contused regions was observed by HE staining on 3 and 14 days post-injury. The content of glutamic acid (Glu) and GABA in hippocampal tissues was examined on 1, 3, 7, 14, 28 days after injury by ELISA. On third day post-injury, hippocampal-dependent spatial memory was measured for 5 days without intermittent. NSCs in culture have the ability to proliferate and differentiate into different phenotypes of neural cells. After transplantation of NSCs, the proliferation of astrocytes around injured site was significantly inhibited compared to the injured group. At the same time the survival of neurons in hippocampal CA1 region were much more than those in injured group on 14 days post-injury. Meanwhile, the cognitive functions in NSC transplanted group was remarkably improved compared with injured group (p < 0.05). Furthermore, NSCs transplantation dramatically inhibited the release of Glu and maintained the content of GABA in injured hippocampal tissues on 1, 3, 7, 14, 28 days post-injury, which was of difference in statistics (p < 0.05). NSCs transplantation can effectively alleviate the formation of glial scar, enhance the survival of hippocampal neurons and improve cognitive function defects in rats with TBI. The underlying mechanism may be related to their effects on inhibiting the release of Glu and maintaining the content of GABA, so as to down-regulate excitotoxicity of neurotransmitter and improve the micro-environment in injured sites.

2.
Theranostics ; 9(24): 7200-7209, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695762

RESUMO

Reactive oxygen species (ROS)-generating anticancer agents can act through two different mechanisms: (i) elevation of endogenous ROS production in mitochondria, or (ii) formation/delivery of exogenous ROS within cells. However, there is a lack of research on the development of ROS-generating nanosystems that combine endogenous and exogenous ROS to enhance oxidative stress-mediated cancer cell death. Methods: A ROS-generating agent based on polymer-modified zinc peroxide nanoparticles (ZnO2 NPs) was presented, which simultaneously delivered exogenous H2O2 and Zn2+ capable of amplifying endogenous ROS production for synergistic cancer therapy. Results: After internalization into tumor cells, ZnO2 NPs underwent decomposition in response to mild acidic pH, resulting in controlled release of H2O2 and Zn2+. Intriguingly, Zn2+ could increase the production of mitochondrial O2·- and H2O2 by inhibiting the electron transport chain, and thus exerted anticancer effect in a synergistic manner with the exogenously released H2O2 to promote cancer cell killing. Furthermore, ZnO2 NPs were doped with manganese via cation exchange, making them an activatable magnetic resonance imaging contrast agent. Conclusion: This study establishes a ZnO2-based theranostic nanoplatform which achieves enhanced oxidative damage to cancer cells by a two-pronged approach of combining endogenous and exogenous ROS.

3.
Sci Rep ; 9(1): 15125, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31641184

RESUMO

Primary renal lymphoma (PRL) is a rare lymphoid malignancy with only a few cases reported in the literature. We performed a population-based study of PRL to determine its incidence, clinical characteristics and factors associated with survival using the Surveillance, Epidemiology, and End Results (SEER) database. We identified 723 patients with PRL. The most common histological subtype of PRL was diffuse large B-cell lymphoma (56.3%). The incidence and mortality rate of PRL was 0.053/100,000 person-years and 0.036/100,000 person-years, respectively. The incidence rate of PRL was increasing significantly with an annual percentage change (APC) of 3.45% (p < 0.001). The 1-year and 5-year relative survival (RS) rates of patients with PRL were 78% and 64%. The RS of patients diagnosed between 2000 to 2013 was better than that of patients diagnosed between 1980-1999. A multivariate Cox hazards regression analysis revealed that older age, male gender, diagnosis before 2000, advanced stage, not receiving surgical treatment, and DLBCL or T/NK cell lymphoma type were independent predictors of unfavorable survival.

4.
Chem Commun (Camb) ; 55(82): 12408-12411, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31566641

RESUMO

We disclose herein the development of a versatile 1,2-diol directing template for palladium-catalyzed remote meta-C-H functionalization of aromatic aldehydes and ketones. In situ-generation of acetals and ketals, as well as removal afterwards, makes the C-H bond functionalization process more straightforward and efficient. This also represents the first example of chelation-directed meta-C-H functionalization of aromatic aldehydes and ketones.

5.
J Transl Med ; 17(1): 335, 2019 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-31585536

RESUMO

BACKGROUND: The P38 mitogen-activated protein kinase (MAPK) pathway plays an essential role in CVB3-induced diseases. We previously demonstrated microRNA-21 has potential inhibitory effect on the MAP2K3 which locates upstream of P38 MAPK and was upregulated in mouse hearts upon CVB3 infection. However, the effect and underlying mechanism of miRNA-21 on CVB3 infection remain unclear. METHODS: We detected continuous changes of cellular miRNA-21 and P38 MAPK proteins expression profiling post CVB3 infection in vitro within 12 h. P38 MAPK signaling was inhibited by the specific inhibitor, small interfering RNA and miRNA-21 mimic in vitro, CVB3 replication, cell apoptosis rate and proliferation were detected. Viral load in the mice heart, cardiomyocyte apoptosis rate and histological of the heart were also detected in the mice model of viral myocarditis pretreated with miRNA-21-lentivirus. RESULTS: We observed significant upregulation of miRNA-21 expression followed by suppression of the MAP2K3/P38 MAPK signaling in CVB3-infected Hela cells. The inactivation of the MAP2K3/P38 MAPK signaling by P38 MAPK specific inhibitor, small interfering RNA against MAP2K3, or miRNA-21 overexpression significantly inhibited viral progeny release from CVB3-infected cells. Mechanistically, when compared with control miRNA, miRNA-21 showed no effect on capsid protein VP1 expression and viral load within host cells, while significantly reversing CVB3-induced caspase-3 activation and cell apoptosis rate, further promoting proliferation of infected cells, which indicates the inhibitory effect of miRNA-21 on CVB3 progeny release. In the in vivo study, when compared with control miRNA, miRNA-21 pretreatment remarkably inactivated the MAP2K3/P38 MAPK signaling in mice and protected them against CVB3 infection as evidenced by significantly alleviated cell apoptosis rate, reduced viral titers, necrosis in the heart as well as by remarkably prolonged survival time. CONCLUSIONS: miRNA-21 were reverse correlated with P38 MAPK activation post CVB3 infection, miRNA-21 overexpression significantly inhibited viral progeny release and decreased myocytes apoptosis rate in vitro and in vivo, suggesting that miRNA-21 may serve as a potential therapeutic agent against CVB3 infection through targeting the MAP2K3/P38 MAPK signaling.

6.
Nutr Diabetes ; 9(1): 28, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591391

RESUMO

BACKGROUND: Gestational diabetes mellitus (GDM) is a temporary form of diabetes during pregnancy, which influences the health of maternal-child in clinical practice. It is still urgent to develop new effective treatment for GDM. Naringenin is a bioactive ingredient with multiple activities including anti-diabetic. In current study, the effects of naringenin on GDM symptoms, insulin tolerance, inflammation, and productive outcomes were evaluated and the underlying mechanisms were explored. METHODS: We administrated naringenin to GDM mice and monitored the GDM symptoms, glucose and insulin tolerance, inflammation and productive outcomes. We established tumor necrosis factor alpha (TNF-α)-induced insulin resistance skeletal muscle cell model and evaluated the effects of naringenin on reactive oxygen species (ROS) production, glucose uptake and glucose transporter type 4 (GLUT4) membrane translocation. RESULTS: We found that naringenin ameliorated GDM symptoms, improved glucose and insulin tolerance, inhibited inflammation, and improved productive outcomes. It was further found that naringenin inhibited TNF-α-induced ROS production, enhanced GLUT4 membrane translocation, and glucose uptake, which were abolished by inhibition of AMP-activated protein kinase (AMPK). CONCLUSION: Naringenin improves insulin sensitivity in gestational diabetes mellitus mice in an AMPK-dependent manner.

7.
J Dairy Sci ; 102(11): 9702-9710, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31477297

RESUMO

Monitoring Staphylococcus aureus with high sensitivity is very important for ensuring milk quality and food safety. In this study, we used a rapid nucleic acid isothermal amplification method, saltatory rolling circle amplification (SRCA), for the detection of Staph. aureus in milk. The results of the SRCA method can be assessed visually by the presence of white precipitate or by fluorescence measurement. Thirteen Staph. aureus strains and 31 non-Staph. aureus strains were used to evaluate the specificity of SRCA. The method exhibited excellent detection of Staph. aureus genomic DNA at a concentration of 7.8 × 101 fg/µL when assessed by visible precipitate, and at 7.8 × 100 fg/µL when detected by fluorescence after addition of the fluorochrome SYBR Green I. In artificially inoculated milk, the detection limits of SRCA were 5.6 × 102 cfu/mL by precipitate and 5.6 × 101 cfu/mL by fluorescence, respectively. Compared with conventional PCR approaches, the SRCA assay achieved at least 100-fold higher sensitivity. Moreover, the sensitivity, specificity, and accuracy of the SRCA-based system were calculated to be 100.00, 97.73, and 97.78%, respectively. These results indicate that SRCA has potential application as a sensitive and visual technique for the detection of Staph. aureus in milk.

8.
Cell Cycle ; 18(21): 2893-2901, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31496367

RESUMO

Rab GTPases have multiple regulatory functions in intracellular vesicle transport. In recent years, there has been an increasing interest in the roles of Rab proteins in mammalian oocytes. In this paper, we show the specific distribution pattern of Rab24 during mouse oocyte meiosis. Furthermore, we find that Rab24 depletion results in the failure of maturational progression in mouse oocytes. Notably, the frequency of meiotic apparatus abnormality is significantly increased in Rab24-depleted oocytes relative to controls. In addition, lagging chromosomes are readily observed in anaphase/telophase oocytes with Rab24 knockdown. In support of this, the depletion of Rab24 disturbs the kinetochore-microtubule attachments in oocytes, and contributes to the production of aneuploid eggs. Taken together, the results of this study identify Rab24 as a novel factor in the modulation of meiotic apparatus assembly and meiotic progression during mouse oocyte maturation.

10.
Acta Biomater ; 97: 321-332, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31523025

RESUMO

For the surgical treatment of coronary artery disease, renal artery stenosis and other peripheral vascular diseases, there is significant demand for small diameter (inner diameter <6 mm) vascular grafts. However, autologous grafts are not always available when the substitute vascular grafts are severely diseased. In our previous work, hybrid small-diameter vascular grafts were successfully fabricated by combining electrospun polycaprolactone (PCL) and decellularized rat aorta (DRA). However, histological assessments of these grafts revealed the development of intimal hyperplasia, indicating potential negative impacts on the long-term patency of these grafts. To address this challenge, PCL nanofibers blended with rapamycin (RM) were electrospun outside the decellularized vascular graft to fabricate a RM-loaded hybrid tissue-engineered vascular graft (RM-HTEV), endowing the graft with a drug delivery function to prevent intimal hyperplasia. RM-HTEV possessed superior mechanical properties compared to DRA and exhibited a sustained drug release profile. To evaluate the applicability of RM-HTEV in vivo, abdominal aorta transplantation was performed on rats. Doppler sonography showed that the grafts were functional for up to 8 weeks in vivo. Moreover, histological analysis of explanted grafts 12 weeks postimplantation demonstrated that RM-HTEV significantly decreased neo-intimal hyperplasia compared with HTEV, without impairing reendothelialization and M2 macrophage polarization. Overall, RM-HTEV represents a promising strategy for developing small-diameter vascular grafts with great clinical translational potential. STATEMENT OF SIGNIFICANCE: In this study, a new type of rapamycin-loaded hybrid tissue-engineered vascular graft (RM-HTEV) was fabricated using electrospinning technology. The unique hybrid bi-layer structure endowed the RM-HTEV with multi-functionality: the exterior rapamycin-loaded electrospun PCL nanofibrous layer enhanced the mechanical properties of the graft and possessed drug releasing property; the interior decellularized aorta layer with porous structure could facilitate cell proliferation and migration. In in vivo implantation experiment, RM-HTEV exhibited satisfying long-term patency rate and significantly inhibited intimal hyperplasia without impairing re-endothelialization and M2 macrophage polarization. This strategy is expected to be a promising strategy for developing bioactive small-diameter vascular grafts with great clinical translational potential.

11.
Sensors (Basel) ; 19(19)2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31557838

RESUMO

Light detection and ranging (LiDAR) is one of the popular technologies to acquire critical information for building information modelling. To allow an automatic acquirement of building information, the first and most important step of LiDAR technology is to accurately determine the important gesture information that micro electromechanical (MEMS) based inertial measurement unit (IMU) sensors can provide from the moving robot. However, during the practical building mapping, serious errors may happen due to the inappropriate installation of a MEMS-IMU. Through this study, we analyzed the different systematic errors, such as biases, scale errors, and axial installation deviation, that happened during the building mapping, based on a robot equipped with MEMS-IMU. Based on this, an error calibration model was developed. The problems of the deviation between the calibrated and horizontal planes were solved by a new sampling method. For this method, the calibrated plane was rotated twice; the gravity acceleration of the six sides of the MEMS-IMU was also calibrated by the practical values, and the whole calibration process was completed after solving developed model based on the least-squares method. Finally, the building mapping was then calibrated based on the error calibration model, and also the Gmapping algorithm. It was indicated from the experiments that the proposed model is useful for the error calibration, which can increase the prediction accuracy of yaw by 1-2° based on MEMS-IMU; the mapping results are more accurate when compared to the previous methods. The research outcomes can provide a practical basis for the construction of the building information modelling model.

12.
Int J Biometeorol ; 63(12): 1597-1609, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31414185

RESUMO

Rice (Oryza sativa) growth is always threatened by heat as well as cold stress, when it is exposed to natural environment. Heat growing degree hours (HGDH) and cold growing degree hours (CGDH1 and CGDH2) were firstly proposed to quantify heat and cold stress occurred during different growing stages. Information diffusion method was effectively used to fit the distribution and estimate probability of single stress at each station, with an advantage of no limitation in data series. In terms of single stress, highest probability was seen in HGDH, followed by CGDH1 and CGDH2. Seven copula functions, i.e., normal and t, Gumbel-Hougaard, Clayton, Frank, Joe, and Ali-Mikhail-Haq, were applied to fit the distribution of multi-stress with significant dependence, and simple calculation based on single stress was used to quantify the probability for multi-stress with independence. In these copulas, t was the most chosen one in the fitting of HGDH-CGDH1, HGDH-CGDH2, CGDH1-CGDH2, and HGDH-CGDH1-CGDH2, selected by the statistic of Akaike information criterion. Regarding bi-stress, higher joint probability was in HGDH-CGDH1, relative to HGDH-CGDH2 and CGDH1-CGDH2. As expected, the co-occurrence probability of tri-stress was lower than that of bi-stress in the magnitude and spatial extent, while joint probability of tri-stress was larger. Given the condition of occurrence of HGDH or CGDH1, the joint probability of HGDH-CGDH1 was higher than other pairs of bi-stress and tri-stress. It was special that higher joint probability of CGDH1-CGDH2 was detected under the condition of CGDH2 relative to CGDH1. Joint probability of tri-stress was lower under the condition of HGDH-CGDH1, in comparison with HGDH-CGDH2 and CGDH1-CGDH2. Hazards of single stress and multi-stress were expressed by the integration of intensity of stress index and corresponding probability. Most consistent conclusions agreed that central Fujian, Zhejiang, and northeastern Jiangxi were exposed to higher hazard, derived from not only single stress but also multi-stress. These results can be helpful in provision of information regarding prevention and adaptation strategies for rice cultivation as a response to extreme temperature stress.


Assuntos
Oryza , China , Temperatura Baixa , Resposta ao Choque Frio , Temperatura Alta
13.
Angew Chem Int Ed Engl ; 58(41): 14758-14763, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31429173

RESUMO

Reactive oxygen species (ROS) can be used not only as a therapeutic agent for chemodynamic therapy (CDT), but also as a stimulus to activate release of antitumor drugs, achieving enhanced efficacy through the combination of CDT and chemotherapy. Here we report a pH/ROS dual-responsive nanomedicine consisting of ß-lapachone (Lap), a pH-responsive polymer, and a ROS-responsive polyprodrug. In the intracellular acidic environment, the nanomedicine can realize pH-triggered disassembly. The released Lap can efficiently generate hydrogen peroxide, which will be further converted into highly toxic hydroxyl radicals via the Fenton reaction. Subsequently, through ROS-induced cleavage of thioketal linker, doxorubicin is released from the polyprodrug. In vivo results indicate that the cascade of ROS generation and antitumor-drug release can effectively inhibit tumor growth. This design of nanomedicine with cascade reactions offers a promising strategy to enhance antitumor efficacy.

14.
Hum Mol Genet ; 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31384951

RESUMO

Germ cell-derived genomic structure variants not only drive the evolution of species but also induce developmental defects in offspring. The genomic structure variants have different types, but most of them are originated from DNA double-strand breaks (DSBs). It is still not well known whether DNA DSBs exist in adult mammalian oocytes and how the growing and fully-grown oocytes repair their DNA DSBs induced by endogenous or exogenous factors. In this study we detected the endogenous DNA DSBs in the growing and fully-grown mouse oocytes, and found that the DNA DSBs mainly localized at the centromere-adjacent regions which are also copy number variation hotspots. When the exogenous DNA DSBs were introduced by Etoposide, we found that Rad51-mediated homologous recombination (HR) was used to repair the broken DNA. However, the HR repair caused the chromatin intertwined and impaired the homologous chromosome segregation in oocytes. Although we hadn't detected the indication about HR repair of endogenous centromere-adjacent DNA DSBs, we found that Rad52 and RNA:DNA hybrids colocalized with these DNA DSBs, indicating a Rad52 dependent DNA repair might exist in oocytes. In summary, our results not only demonstrated an association between endogenous DNA DSBs with genomic structure variants, but also revealed one specific DNA DSB repair manner in oocytes.

15.
Lab Chip ; 19(18): 3116-3122, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31429847

RESUMO

The integration of one more gain media in droplet microlasers with morphology-dependent modes, which can be employed in optofluidic systems as multi-wavelength lasing sources, is highly attractive and demands new cavity design and fabrication approaches. Here, cholesteric liquid crystal (CLC) droplets with an integrative triple-emulsion cavity are fabricated via glass-capillary-based microfluidic technologies and dual-gain lasing with variable modes, flexibly configured by the combination and incorporation of gain dyes and CLCs into both the core and shell. The distributed feedback (DFB) mode, formed by the feedback from the self-assembled helix periodic structure of CLCs, the whispering gallery (WG) mode, and the hybrid, is selectively excited by controlling the spatial coupling between the pump beam and the droplet with gain. With the merits of dual-gain and controllable lasing, a prototype dual-wavelength-ratiometric thermometer with self-calibration capability is expected to be developed. Furthermore, the anisotropic CLC core is substituted with an isotropic fluid and the gain from the CLC shell is additionally removed, DFB lasings in both shell and core are absent, and only Bragg-shell reflection-based hybrid modes are excited for lasing. The CLC droplet microlasers with an integrative cavity are expected to provide a new route to future lab-on-chip (LOC) applications.

16.
Am J Physiol Heart Circ Physiol ; 317(5): H1105-H1115, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31347915

RESUMO

Human pluripotent stem cell (hPSCs)-derived ventricular (V) cardiomyocytes (CMs) display immature Ca2+-handing properties with smaller transient amplitudes and slower kinetics due to such differences in crucial Ca2+-handling proteins as the poor sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump but robust Na+-Ca2+ exchanger (NCX) activities in human embryonic stem cell (ESC)-derived VCMs compared with adult. Despite their fundamental importance in excitation-contraction coupling, the relative contribution of SERCA and NCX to Ca2+-handling of hPSC-VCMs remains unexplored. We systematically altered the activities of SERCA and NCX in human embryonic stem cell-derived ventricular cardiomyocytes (hESC-VCMs) and their engineered microtissues, followed by examining the resultant phenotypic consequences. SERCA overexpression in hESC-VCMs shortened the decay of Ca2+ transient at low frequencies (0.5 Hz) without affecting the amplitude, SR Ca2+ content and Ca2+ baseline. Interestingly, short hairpin RNA-based NCX suppression did not prolong the transient decay, indicating a compensatory response for Ca2+ removal. Although hESC-VCMs and their derived microtissues exhibited negative frequency-transient/force responses, SERCA overexpression rendered them less negative at high frequencies (>2 Hz) by accelerating Ca2+ sequestration. We conclude that for hESC-VCMs and their microtissues, SERCA, rather than NCX, is the main Ca2+ remover during diastole; poor SERCA expression is the leading cause for immature negative-frequency/force responses, which can be partially reverted by forced expression. Combinatorial approach to mature calcium handling in hESC-VCMs may help shed further mechanistic insights.NEW & NOTEWORTHY In this study of human pluripotent stem cell-derived cardiomyocytes, we studied the role of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and Na+-Ca2+ exchanger (NCX) in Ca2+ handling. Our data support the notion that SERCA is more effective in cytosolic calcium removal than the NCX.

17.
Aquat Toxicol ; 214: 105257, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31336221

RESUMO

The interactions between nanoparticles (NPs) and metals in aquatic environments may modify the bioavailability and toxicity of metals to organisms. In this study, we investigated the effects of titanium dioxide NPs (n-TiO2) on the bioconcentration, depuration, and neurotoxic effects of lead (Pb) in zebrafish larvae. Transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed that Pb2+ was adsorbed by n-TiO2 to form NP-Pb complexes in suspension, and these complexes were observed in larval tissues. The bioconcentration of Pb in larvae along with the depuration rates of Pb were higher in the presence of n-TiO2 compared to when n-TiO2 was absent. Exposure to Pb alone induced the expression of the biomarker metallothionein, downregulated neurodevelopment-related genes, and reduced swimming activity of larvae. However, the addition of n-TiO2 to the exposure solution alleviated these effects. The results suggest that n-TiO2 can act as a carrier of Pb to increase its bioconcentration; however, the formation of NP-Pb complexes likely reduces the amount of free Pb2+, thereby reducing toxicity to larvae.


Assuntos
Chumbo/toxicidade , Nanopartículas/toxicidade , Titânio/toxicidade , Peixe-Zebra/metabolismo , Adsorção , Animais , Comportamento Animal/efeitos dos fármacos , Disponibilidade Biológica , Larva/efeitos dos fármacos , Larva/genética , Larva/ultraestrutura , Locomoção/efeitos dos fármacos , Metalotioneína/metabolismo , Nanopartículas/ultraestrutura , Suspensões , Transcrição Genética/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética
18.
Artigo em Inglês | MEDLINE | ID: mdl-31352348

RESUMO

Molecular signatures of cancer, e.g., genes or microRNAs (miRNAs), have been recognized very important in predicting the occurrence of cancer. From gene-expression and miRNA-expression data, the challenge of identifying molecular signatures lies in the huge number of molecules compared to the small number of samples. To address this issue, in this work, we propose a heuristic algorithm to identify molecular signatures, termed HAMS, for cancer diagnosis by modeling it as a multi-objective optimization problem. In the proposed HAMS, an elitist-guided individual update strategy is proposed to obtain a small number of molecular signatures which are closely related with cancer and contain less redundant signatures. Experimental results demonstrate that the proposed HAMS achieves superior performance over seven state-of-the-art algorithms on both gene-expression and miRNA-expression datasets. We also validate the biological significance of the molecular signatures obtained by the proposed HAMS through biological analysis.

19.
Sci Data ; 6(1): 105, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31263100

RESUMO

While tick-borne zoonoses, such as Lyme disease and tick-borne encephalitis, present an increasing global concern, knowledge of their vectors' distribution remains limited, especially for China. In this paper, we present the first comprehensive dataset of known tick species and their distributions in China, derived from peer-reviewed literature published between 1960 and 2017. We searched for journal articles, conference papers and degree thesis published in both English and Chinese, extracted geographic information associated with tick occurrence, and applied quality-control procedures to remove duplicates and ensure accuracy. The dataset contains 5731 records of geo-referenced occurrences for 123 tick species distributed over 1141 locations distinguished at four levels of scale i.e., provincial, prefectural, county, and township and finer. The most frequently reported tick species include Haemaphysalis longicornis, Dermacentor silvarum, Ixodes persulcatus, Haemaphysalis conicinna, Rhipicephalus microplus, and Rhipicephalus sanguineus sensu lato. The geographical dataset provides an improved map of where ticks inhabit China and can be used for a variety of spatial analyses of ticks and the risk of zoonoses they transmit.

20.
PLoS One ; 14(7): e0219735, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31318936

RESUMO

Coal and gas outburst is a common coal-rock dynamic disaster. Such accidents frequently occur, and the mechanism underlying the occurrence of these outbursts is complex. As a typical failure mode of a gas-filled and pressure-relieved coal body, the spallation mechanism should be investigated to reveal the mechanism of coal and gas outburst and guide outburst-prevention strategies. In this paper, a fluid-solid coupling model for coal seam gas flow is established. This model considers the adsorption characteristics of coal. Numerical calculations are used to simulate the stress field distribution and evolution of gas-filled coal bodies under different boundary conditions. The mechanical mechanism of the spallation occurrence after the pressure relief of coal is explained from the perspective of seepage breaking coal. The control of the flow and stress state of the gas to the spallation failure is analyzed. The mechanical-quantitative conditions for the initial failure of the coal body under seepage and the mechanical-qualitative conditions for the continuous advancement and termination of spallation are studied based on numerical solution results. The numerical calculation results show that the formation of a flow field after pressure relief will apply a drag force (tensile stress) on the porous media of coal. The presence of this force plays a crucial role in promoting the spallation and cracking of coal and, thus, the promotion of spallation. The tensile strength, initial adsorption pressure, and pressure relief rate of the coal body jointly control whether the initial failure can occur and the thickness of the fracture layer cracks. Spallation propulsion is mainly determined by the pressure relief conditions of the undestroyed coal body and pressure changes in the spallation space; the former can be quantitatively obtained by numerical calculations, whereas the latter is related to the thickness of the spalled layer and the degree of the layer-crack structure.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA