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1.
Med Biol Eng Comput ; 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900817

RESUMO

Concentric tube robot (CTR) has gradually attracted the attention of researchers on the basis of its small size and curved shape control ability. However, most of current experimental prototypes of CTR are single-arm structure, which can only carry out simple operation such as drug delivery or monitoring. In this paper, design and analysis of a three-arm CTR system is proposed. It has a four-DOF vision arm and two six-DOF manipulator arms, which equipped with special end effectors to achieve different surgical operations. Finally, a mean motion accuracy of 0.33 mm has been obtained quantitatively through teleoperation experiments. Moreover, tissue excision experiment in skull model is carried out to prove the effectiveness and feasibility of the proposed CTR system in nasopharyngeal carcinoma surgery. Graphical Abstract Platform of the proposed Multi-Arm Concentric Tube Robot system. (a) Configuration of the end-effectors with the CTR system. (b) The setup of the tissue removal experiment in a skull model.

2.
Nanomedicine (Lond) ; 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31950875

RESUMO

Aim: Previously, different results have been achieved regarding effects of silver nanoparticles (Ag NPs) on osteogenesis of stem cells and the mechanisms have not been disclosed yet, which are quite important for potential application of Ag NPs in bone reconstruction. Materials & methods: Effects of Ag NPs on osteogenesis of human mesenchymal stem cells (hMSCs) with underlying mechanisms were investigated. Results: Ag NPs at 2.5 and 5 µg/ml increased osteogenic proteins expression and mineralization of hMSCs. Meanwhile, autophagy was activated by Ag NPs and it could be inhibited by 3-methyladenine. Furthermore, osteogenesis induced by Ag NPs could also be reversed by 3-methyladenine. Conclusion: These findings suggest that autophagy is involved in stimulating osteogenesis of hMSCs induced by Ag NPs.

3.
ACS Appl Mater Interfaces ; 12(2): 2634-2643, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31894956

RESUMO

A facile, one-step hydrothermal route was exploited to prepare SnO2-decorated reduced graphene oxide hydrogel (SnO2/RGOH) with three-dimensional (3D) porous structures for NO2 gas detection. Various material characterizations demonstrate the effective deoxygenation of graphene oxide and in situ growth of rutile SnO2 nanoparticles (NPs) on 3D RGOH. Compared with the pristine RGOH, the SnO2/RGOH displayed much lower limit of detection (LOD) and an order of magnitude higher sensitivity, revealing the distinct impact of SnO2 NPs in improving the NO2-sensing properties. An exceptional low theoretical LOD of 2.8 ppb was obtained at room temperature. The p-n heterojunction formed at the interface between RGOH and SnO2 facilitates the charge transfer, improving both the sensitivity in NO2 detection and the conductivity of hybrid material. Considering that existing SnO2/RGO-based NO2 sensors suffer from great vulnerability to humidity, here we employed integrated microheaters to effectively suppress the response to humidity, with nearly unimpaired response to NO2, which boosted the selectivity. Notably, a flexible NO2 sensor was constructed on a liquid crystal polymer substrate with endurance to mechanical deformation. This work indicates the feasibility of optimizing the gas-sensing performance of sensors by combining rational material hybridization, 3D structural engineering with temperature modulation.

4.
Org Lett ; 22(2): 760-763, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31908165

RESUMO

Recently, a paper in this journal reported the isolation and structure determination of hypatulone A. Several features of the proposed structure and biosynthesis induced us to reexamine the compound's NMR spectra. Now we propose a revised structure, confirm it with quantum computations, and suggest a reasonable radical-mediated biosynthetic pathway to the revised structure. Our work illustrates how both biosynthetic considerations and quantum computations can complement spectroscopic structure determination.

5.
Bioelectrochemistry ; 131: 107396, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31704455

RESUMO

We report a novel chiral interface based on polysaccharides that was integrated via an amidation reaction between the COOH of sodium alginate and the NH2 of chitosan to form a chiral selector (SA-CS) with three dimensional N-doped graphene-CNT (NGC) as the substrate material. This interface was used for chiral discrimination of tryptophan (Trp) enantiomers via electrochemical measurements. The FT-IR, SEM, TEM and XPS characterization showed that the chiral selector and substrate materials were prepared successfully. Compared with individual SA-CS and NGC, the integrated polysaccharides/3D NGC showed higher enantioselectivity for L-Trp than D-Trp due to the smaller steric hindrance for D-Trp during the formation of three-point interactions between the two diastereoisomeric enantiomer-selector complexes, which allowed L-Trp to more easily detach from the electrode modification layer and approach the electrode surface, facilitating its approach and confirming that SA-CS had a higher constant for L-Trp when applied to real samples.


Assuntos
Técnicas Eletroquímicas/métodos , Grafite/química , Nitrogênio/química , Polissacarídeos/química , Estereoisomerismo , Termodinâmica
6.
Sci Total Environ ; 706: 135898, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31864997

RESUMO

A field study was conducted to investigate the effect of Fe-based biochar application on the extractability and availability of Cd and As, as well as its impact on crop growth and yield under a two-years wheat-rice rotation system. The Fe-based biochar was applied to the soil at 1.5 and 3.0 t ha-1, manure compost was also applied as a comparison, as well as a non-treated control. The application of the Fe-based biochar significantly (p < 0.05) increased the crop yields for the rice season in the first year, but the both treatments had no significant effect on the crop yields in the others cultivation seasons, compared to the control. The concentrations of available Cd and As significantly (p < 0.05) decreased after either higher or lower dose of Fe-based biochar addition, especially with lower rate in the second year. In the second year, the soil extractable Cd and As reduced by 57% and 18%, respectively, in the wheat season and 63% and 14%, respectively, in the rice season, after the lower dose of Fe-based biochar was applied. The lower dose of the Fe-based biochar treatment showed higher efficiency for decreasing Cd and As availability in soil than the higher one, the control and manure compost treatment. Additionally, both the higher and lower doses of the Fe-based biochar treatments significantly decreased Cd and As uptake by wheat and rice plants. Overall, the Fe-based biochar showed effective immobilization at an application of 1.5 t ha-1, making the use of the Fe-based biochar feasible as an amendment for the safe use of agricultural land contaminated by Cd and As.

7.
J Neurosci Res ; 98(2): 353-370, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31359506

RESUMO

The relationships of digit ratio (2D:4D) with the length of AR (CAG)n, and testosterone levels from saliva and blood have been extensively debated over the years. This research including three studies further clarifies such controversies. To do so, we re-examined the relationships between the length of AR (CAG)n, 2D:4D, and current testosterone levels, through replication study and meta-analysis for each study. The results indicate: (a) the length of AR (CAG)n is not significantly associated with 2D:4D; (b) current testosterone levels are not significantly associated with the ratio; and (c) the length is not significantly associated with testosterone levels. Thus, AR (CAG)n and current testosterone levels are not significantly related to 2D:4D at individual level.

8.
World J Gastroenterol ; 25(43): 6404-6415, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31798277

RESUMO

BACKGROUND: Developing mitochondrial regulators/nutrients from natural products to remedy mitochondrial dysfunction represent attractive strategies for therapy of non-alcoholic fatty liver disease (NAFLD). Polygonatum kingianum (PK) has been traditionally used in China as a medicinal and nutritional ingredient for centuries and can alleviate high-fat diet (HFD)-induced NAFLD by promoting mitochondrial functions. To date, the underlying molecular mechanism of PK for treating mitochondrial dysfunctions and thus alleviating NAFLD remains unclear. AIM: To identify the molecular mechanism behind the mitochondrial regulatory action of PK against HFD-induced NAFLD in rats. METHODS: NAFLD model was induced in rats with HFD. The rats were intragastrically administered PK (4 g/kg per day) for 14 wk. Metabolites in hepatic mitochondrial samples were profiled through ultra-high performance liquid chromatography/mass spectrometry followed by multivariate statistical analysis to find the potential biomarkers and metabolic pathways. RESULTS: PK significantly restored the metabolites' levels in the mitochondrial samples. Ten potential biomarkers were identified in the analyzed samples. These biomarkers are involved in riboflavin metabolism. CONCLUSION: PK can alleviate HFD-induced NAFLD by regulating the riboflavin metabolism and further improving the mitochondrial functions. Thus, PK is a promising mitochondrial regulator/nutrient for alleviating NAFLD-associated diseases.

9.
Front Microbiol ; 10: 2696, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31824465

RESUMO

The majority of emerging and reemerging zoonotic viral pathogens are RNA viruses. Pathogen discovery programs of emerging infectious diseases (EIDs) in wildlife have implicated rodents and shrews as hosts of diverse human pathogens, such as hantaviruses, arenaviruses, paramyxoviruses, etc. Despite these threats, little is known about the diversity of viruses circulating among rodents and shrews in Kenya, meaning the risk of infectious disease outbreak from these small mammals could be oblivious. This study reports the first surveillance toward understanding the diversity of RNA viruses carried by rodents and shrews in areas of high-potential contact with humans in Kenya through molecular detection. A total of 617 samples comprising fecal, urine, and tissues from 138 rodents and 5 shrews were screened for eight different families of viruses using RT-PCR assays. The results highlight the presence of diverse astroviruses, paramyxoviruses, hepeviruses, and arenavirus, circulating in both wild and synanthropic Kenyan rodents and shrews. Most of the viruses detected in this study are novel strains and some belong to the families that contain important human viral pathogens. Notably, a novel arenavirus was detected in Grammomys macmillani, a rodent species newly identified to harbor arenavirus, and it potentially represent a novel arenavirus species. Our findings demonstrate the need for continued pathogen surveillance among these small mammals as well as among the vulnerable and exposed livestock and humans. This would help in development and implementation of effective preventive and control strategies on EIDs in countries with rich wildlife biodiversity like Kenya.

10.
ACS Appl Mater Interfaces ; 11(46): 43383-43392, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31709789

RESUMO

A multifunctional sensor comprising humidity, temperature, and flow detection capabilities is fabricated with a facile, single-layered device structure. A microheater based on serpentine Pt microlines plays key roles in both humidity and flow sensing at the hot state by introducing an efficient Joule heating effect, and meanwhile functions as a reliable thermistor at the cold state for accurate temperature measurement. For the first time, the strong temperature-dependent humidity-sensing properties of graphene oxide (GO) are revealed using the microheater platform. The GO-based humidity sensor displays ultrahigh sensitivity [124/% relative humidity (RH)], fast response time (3 s), wide detection range (8-95% RH) at room temperature, while the sensitivity drops at elevated temperatures, indicating the non-negligible temperature effect. Interestingly, a linear relationship between sensitivity and voltage is observed for the flow sensor, indicating the capability to manipulate sensitivity by conveniently modifying the voltage applied on the microheater. Because the three sensors work independently with distinguishable output signals, multiparametric sensing is enabled to monitor various human activities, such as respiration, noncontact sensation, and so forth. This work develops a simple, cost-effective, and useful multiparametric-sensing platform using a microheater for potential applications in the growing fields of internet of things, healthcare monitoring, and human-machine interfaces.

11.
Nat Prod Res ; : 1-6, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31711315

RESUMO

A new phenylpentenol, wortmannine H (1) was isolated from Talaromyces wortmannii LGT-4, an endophytic fungus of Tripterygium wilfordii. The structure of 1 was elucidated by IR, MS, 1D and 2D NMR spectra and comparison of the experimental and calculated optical rotatory dispersion (ORD). Monoamine oxidase (MAO), acetylcholinesterase (AChE) and phosphoinositide 3-kinase (PI3Kα) inhibitory activities of 1 was also tested. The compound did not show good biological activity.

12.
Fitoterapia ; 139: 104400, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31669962

RESUMO

Two novel epimer pairs of acetaminophen derivatives penicilquei A-D (1-4) were isolated from Penicillium herquei JX4. Their structures were elucidated using comprehensive spectroscopic methods. The absolute configurations of penicilquei A-D (1-4) were determined by modifified Mosher's method, and comparing their experimental and calculated electronic circular dichroism (ECD) spectra. Penicilquei A-D (1-4) are the first example of acetaminophen derivatives featuring an unprecedented carbon skeleton. The inhibitory activities of all compounds against nine phytopathogenic fungi and α-glucosidase were evaluated. Penicilquei A-D (1-4) showed strong inhibitory activities against at least eight phytopathogenic fungus.

13.
Sci Rep ; 9(1): 16762, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31728043

RESUMO

The 2008 Wenchuan earthquake caused significant economic losses and degradation of regional ecosystems, including the terrestrial vegetation. Since the vegetation root system can enhance the soil's anti-erosion capacity and therefore mitigate the occurrence of slope instabilities, it is beneficial to study the spatial and temporal evolution of vegetation for a long-term assessment of co-seismic secondary disasters. The Mianyuan River Basin, an uninhabited area passing through an active fault located in the earthquake-affected region, was selected as the study area. The Normal Difference Vegetation Index (NDVI) was calculated using remote sensing images from 1994 to 2017 to analyze the process of vegetation growth, loss, fluctuation and recovery. Statistical results suggest that the area in the middle and lower reaches, near the river network, and with a slope of 30 to 40 degrees were variable regions, showing more significant vegetation destruction during the earthquake and faster repair after the seismic event. Besides, vegetation near the fault was damaged more severely after the earthquake, but the active fault did not play an essential role in the vegetation recovery period. In the Mianyuan River Basin, vegetation experienced a volatility period (5 plus or minus one year) before entering the recovery period. In 8 to 9 years after the earthquake, the surficial vegetation could recover to the state before the earthquake.

14.
Artigo em Inglês | MEDLINE | ID: mdl-31781042

RESUMO

The aim of this retrospective analysis is to explore whether growth hormone (GH) pretreatment is beneficial for patients with poor ovarian reserve undertaking in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment. Poor ovarian reserve patients with anti-Mullerian hormone (AMH) <1.2 ng/mL were recruited and divided into the GH adjuvant group (GH+ group) and the counterpart without GH pretreatment (GH- group). One-to-one case-control matching was performed to adjust essential confounding factors between the GH+ group and GH- group. A total of 676 cycles were included in the present study with 338 cycles in each group. Conventional ovarian stimulation protocols were applied for ART treatment. Patients were further divided into POSEIDON group 3 (PG3, age <35 years) and POSEIDON group 4 (PG4, age ≥35 years), based on POSEIDON criteria. The demographic data, cycle characteristics, and clinical outcomes between the GH+ group and GH- group, as well as in the further stratified analysis of PG3 and PG4 were compared. GH adjuvant showed a beneficial effect on the ovarian response and live birth rate in poor ovarian reserve patients. Further stratification revealed that in PG4, there was a significantly increased number of good-quality embryos in the GH+ group compared to the GH- group (1.58 ± 1.71 vs. 1.25 ± 1.55, P = 0.032), accompanied by a reduced miscarriage rate and a greatly improved live birth rate (29.89 vs. 17.65%, P = 0.028). GH adjuvant failed to promote the live birth rate in PG3. In conclusion, GH pretreatment is advantageous by elevating ovarian response and correlated with an improved live birth rate and reduced miscarriage rate in POSEIDON poor ovarian reserve patients older than 35.

15.
J Chromatogr A ; : 460693, 2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31732154

RESUMO

An ultrasensitive microchip electrophoresis chemiluminescence (MCE-CL) assay platform based on separation assisted cascade signal amplification was developed for detection of trace biomolecules. In this work, the aptamer was used as a target probe to bind target molecule and triggering cascade signal amplification reaction. The horseradish peroxide labeled DNA (HRP-DNA) was used as signal probe, utilizing nucleic acid hybridization and exonuclease cutting technology realized ultrasensitive detection of biomolecules on the MCE-CL assay platform. Taking gamma interferon (IFN-γ) as a model analyte, the linear range for IFN-γ detection is 8.0 × 10-15-1.0 × 10-8 M, the detection limit is 1.6 fM, which is six orders magnitude lower than that of without signal amplification. The proposed method was successfully applied for the quantification of IFN-γ in human plasma samples. It was demonstrated that the MCE-CL assay platform was quick, sensitive, and highly selective. It may serve as a tool for clinical analysis of IFN-γ to assist in the diagnosis of disease.

16.
J Burn Care Res ; 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31735967

RESUMO

Marjolin's ulcer is a type of skin cancer that generated from chronic non-healing trauma. For years, its pathogenesis mechanisms remain unclear. Regarding this situation, we retrospectively analyze the patients admitted to our department from 2005-2019 to presents several representative cases and examines the expression patterns of survivin and its role in this process. Among these patients, the latent period ranges from 2-25 years, with 8.43 years in average. There is no notable relationship between the latent period and age (P=0.643>0.05). Therefore, Marjolijn's ulcer arises from extremities and joints more often compared to other parts (P<0.05). The expression ratio of survivin in Marjolin's ulcer is significantly higher than that in skin ulcer (p<0.05). And the expression ratio of survivin in patients diagnosed with Marjolin's ulcer is also correlated with lymphatic metastasis (p<0.05). Frequent follow-ups and prompt diagnosis and management is necessary as the prognosis is poor for patients with metastasis. Survivin may be a potential target for future development of target therapy in order to maximize the efficacy and improve the quality of life for patients suffering from Marjolin's ulcer.

17.
Photodiagnosis Photodyn Ther ; : 101606, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31759126

RESUMO

OBJECTIVE: To investigate low-level ALA-PDT (Aminolevulinic acid photodynamic therapy) effects on photorejuvenation in vitro and in vivo, exploring the basic mechanism of Bach2 involved in PDT treatment in photoaging. METHOD: Photoaging model was established by UVA chronic irradiation in human fibroblasts and mice skins. Cell viability was determined by MTS assay and cell senescence was detected by SA-ß-gal activity. PDT treatment and Bach2 knockdown with adenovirus in fibroblasts were confirmed by Western blot. RESULTS: UVA chronic irradiation induced photoaging in vitro and in vivo. Treatment of low-level PDT reduced photoaging by decreasing SA-ß-gal activity and cell senescence-related proteins levels of p16 and p21 in fibroblasts. Moreover, low-level PDT treatment accompany with Bach2 accumulation increased in fibroblasts and in mice skin tissues. Bach2 knockdown with adenovirus induced cell senescence and Bach2 depletion with PDT treatment some extent decreased SA-ß-gal activity, but it was no significant change of Bach2 itself and p16 protein levels in fibroblasts. CONCLUSION: Low-level PDT treatment decreased skin photoaging might be through up-regulating Bach2.

18.
Drug Des Devel Ther ; 13: 3683-3692, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695335

RESUMO

Background: Widespread concern of the side effects and the broad-spectrum anticancer property of podophyllotoxin as an antitumor agent highlight the need for the development of new podophyllotoxin derivatives. Although some per-butyrylated glucosides of podophyllotoxin and 4ß-triazolyl-podophyllotoxin glycosides show good anticancer activity, the per-acetylated/free of podophyllotoxin glucosides and their per-acetylated are not well studied. Methods: A few glucoside derivatives of PPT were synthesized and evaluated for their in vitro cytotoxic activities against five human cancer cell lines, HL-60 (leukemia), SMMC-7721 (hepatoma), A-549 (lung cancer), MCF-7 (breast cancer), and SW480 (colon cancer), as well as the normal human pulmonary epithelial cell line (BEAS-2B). In addition, we investigated the structure-activity relationship and the physicochemical property-anticancer activity relationship of these compounds. Results: Compound 6b shows the highest cytotoxic potency against all five cancer cell lines tested, with IC50 values ranging from 3.27±0.21 to 11.37±0.52 µM. We have also found that 6b displays higher selectivity than the etoposide except in the case of HL-60 cell line. The active compounds possess similar physicochemical properties: MSA > 900, %PSA < 20, ClogP > 2, MW > 700 Da, and RB > 10. Conclusion: We synthesized several glucoside derivatives of PPT and tested their cytotoxicity. Among them, compound 6b showed the highest cytotoxicity. Further studies including selectivity of active compounds have shown that the selectivity indexes of 6b are much greater than the etoposide except in the case of HL-60 cell line. The active compounds possessed similar physicochemical properties. This study indicates that active glucoside analogs of podophyllotoxin have potential as lead compounds for developing novel anticancer agents.

19.
Bioorg Chem ; : 103362, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31668463

RESUMO

A novel cyclopentenone derivative, talarocyclopenta A (1), a new phenolicethers derivative, talarocyclopenta B (2) and a new itaconic acid derivative, talarocyclopenta C (3) together with four known itaconic acid derivatives (4-7) were isolated from the Talaromyces assiutensis JTY2. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Among them, talarocyclopent (1) is the first represent an unusual type of cyclopentenone derivative, possessing a cyclopentenone unit, a 2-butanone unit and a 3-hydroxybutyric acid unit. All isolated compounds were evaluated for their anti-inflammatory and antibacterial activities. Compounds 1-4 showed inhibitory activities against the nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro. Compound 2 showed broad spectrum antibacterial against six terrestrial pathogenic bacteria.

20.
Artigo em Inglês | MEDLINE | ID: mdl-31705175

RESUMO

PURPOSE: Accurate evaluation of hypoxia is particularly important in patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy. The aim of this study was to propose a novel imaging strategy for quantitative three-dimensional (3D) evaluation of hypoxia in a small animal model of NPC. METHODS: A carbonic anhydrase IX (CAIX)-specific molecular probe (CAIX-800) was developed for imaging of hypoxia. Mouse models of subcutaneous, orthotopic, and spontaneous lymph node metastasis from NPC (5 mice per group) were established to assess the imaging strategy. A multi-modality imaging method that consisted of a hybrid combination of fluorescence molecular tomography-computed tomography (FMT-CT) and multispectral optoacoustic tomography (MSOT) was used for 3D quantitative evaluation of tumour hypoxia. Magnetic resonance imaging, histological examination, and immunohistochemical analysis were used as references for comparison and validation. RESULTS: In the early stage of NPC (2 weeks after implantation), FMT-CT enabled precise 3D localisation of the hypoxia biomarker with high sensitivity. At the advanced stage (6 weeks after implantation), MSOT allowed multispectral analysis of the biomarker and haemoglobin molecules with high resolution. The combination of high sensitivity and high resolution from FMT-CT and MSOT could not only detect hypoxia in small-sized NPCs but also visualise the heterogeneity of hypoxia in 3D. CONCLUSIONS: Integration of FMT-CT and MSOT could allow comprehensive and quantifiable evaluation of hypoxia in NPC. These findings may potentially benefit patients with NPC undergoing radiotherapy in the future. Graphical abstract A novel multimodality imaging strategy for three-dimensional evaluation of tumour hypoxia in an orthotopic model of nasopharyngeal carcinoma.

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