Abstract Adipose-derived stem cells (ADSCs) represent a valuable source of stem cells for regenerative medicine, but the loss of their stemness during in vitro expansion remains a major roadblock. We ...employed a microgravity bioreactor (MB) to develop a method for biomaterial-free-mediated spheroid formation to maintain the stemness properties of ADSCs. ADSCs spontaneously formed three-dimensional spheroids in the MB. Compared with monolayer culture, the expression levels of E-cadherin and pluripotent markers were significantly upregulated in ADSC spheroids. Spheroid-derived ADSCs exhibited increased proliferative ability and colony-forming efficiency. By culturing the spheroid-derived ADSCs in an appropriate induction medium, we found that the multipotency differentiation capacities of ADSCs were significantly improved by spheroid culture in the MB. Furthermore, when ADSCs were administered to mice with carbon tetrachloride-induced acute liver failure, spheroid-derived ADSCs showed more effective potentials to rescue liver failure than ADSCs derived from constant monolayer culture. Our results suggest that spheroid formation of ADSCs in an MB enhances their stemness properties and increases their therapeutic potential. Therefore, spheroid culture in an MB can be an efficient method to maintain stemness properties, without the involvement of any biomaterials for clinical applications of in vitro cultured ADSCs.
A molecularly imprinted sensor was fabricated for alpha-fetoprotein (AFP) using an ionic liquid as a functional monomer. Ionic liquid possesses many excellent characteristics which can improve the ...sensing performances of the imprinted electrochemical sensor. To demonstrate this purpose, 1-3-(N-cystamine)propyl-3-vinylimidazolium tetrafluoroborate ionic liquid (Cys)VIMBF
was synthesized and used as a functional monomer to fabricate an AFP imprinted polymerized ionic liquid film on a gold nanoparticle modified glassy carbon electrode (GCE) surface at room temperature. After removing the AFP template, a molecularly imprinted electrochemical sensor was successfully prepared. The molecularly imprinted sensor exhibits excellent selectivity towards AFP, and can be used for sensitive determination of AFP. Under the optimized conditions, the imprinted sensor shows a good linear response to AFP in the concentration range of 0.03 ng mL
~5 ng mL
. The detection limit is estimated to be 2 pg mL
.
In the past decades, extremely serious road accidents with a death toll over ten in each have become a severe public health problem in China. This study investigates risk factors contributing to ...extremely serious road accidents, which will be crucial for accident prevention.
Collecting data from The Road Accident Statistical Annual Report openly issued by China's Traffic Management Bureau of the Public Security Ministry for the time period 2004-2015, we used the monthly case number of extreme serious road accidents as the dependent variable. We then selected ten risk factors as primary independent variables: professional driver, driving under influence (alcohol or drug), fatigue, vehicle type, overload, brake problem, weather, road classification, terrain, and region. The method of negative binominal regression was implemented to investigate the association between these risk factors and extremely serious road accidents.
A total of 346 extremely serious road accidents were included in our analysis. On a national scale, we found that professional driver incidence rate ratio (IRR): 1.10, 95% CI: 1.02-1.19, fatigue (IRR: 1.15, 95% CI: 1.03-1.29), large vehicle type (IRR: 1.11, 95% CI: 1.03-1.21), overload (IRR: 1.09, 95% CI: 1.03-1.16), and terrain (IRR: 1.09, 95% CI: 1.01-1.18) were significantly associated with extremely serious road accidents. Besides, separate analyses on western and non-western region indicated that both regions had shared risk factors as well as distinct factors.
Our study identifies professional driver, fatigue, large vehicle type, overload, and terrain as significant risk factors of extremely serious road accidents in China, and targeted and preventative measures could be taken based on our findings.
New graphene–silk peptide (Gr–SP) nanosheets were prepared and successfully fabricated with tyrosinase (Tyr) as a novel biosensor for the determination of phenolic compounds. The Gr–SP nanosheets ...were fully characterized with transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, UV/Vis and FTIR spectra. The developed biosensors were also characterized with scanning electronic microscopy and electrochemical impedance spectroscopy. Using bisphenol A (BPA) as a model substrate in the sensing system, a number of key factors including the volume of Gr–SP–Tyr solution, the applied potential, pH values, temperature, and the Tyr/Gr–SP ratio that influence the analytical performance of the biosensor were investigated. The biosensor gave a linear response on the concentration ranges of 0.001–16.91μM for catechol with the sensitivity of 7634mAM−1cm−2, 0.0015–21.12μM for phenol with the sensitivity of 4082mAM−1cm−2, and 0.002–5.48μM for BPA with the sensitivity of 2511mAM−1cm−2. The low detection limits were estimated to be 0.23, 0.35 and 0.72nM (S/N=3) for catechol, phenol and BPA, respectively. The biosensors also exhibit good repeatability and long-term stability. The practical application of the biosensor was also demonstrated by the determination of BPA leaching from commercial plastic drinking bottles.
► Silk peptide functionalized graphene nanosheets were synthesized and fully characterized; ► Graphene–silk peptide–tyrosinase/glassy carbon electrodes (Gr–SP–Tyr/GCE) were fabricated; ► Electrochemical behaviors of phenolic compounds at Gr–SP–Tyr/GCE were investigated; ► Sensitive amperometric method for phenolic compounds was developed; ► Practical application of the biosensor was demonstrated.
The materials with grain size gradient variation on the surface, which were prepared with mechanical-induced severe plastic deformation, always show high resistance to high and low cycle fatigue and ...frictional wear because of their good strength–ductility synergy. The ultrasonic surface rolling treatment (USRT) has the advantages of high processing efficiency, good surface quality, and large residual compressive stress introduced to the surface after treatment. The USRT was used to prepare aluminum alloy (AA7075) samples with a surface gradient structure; meanwhile, the microstructural evolution mechanism of the deformation layers on the gradient structure was studied with XRD, SEM, and TEM. The microstructure with gradient distribution of grain size and dislocation density formed on the surface of AA7075 aluminum alloy after USRT. The surface layer consists of nanocrystals with random orientation distribution, and high-density dislocation cells and subgrains formed in some grains in the subsurface layer, while the center of the material is an undeformed coarse-grained matrix. The results show that the dislocation slip dominates the grain refinement process, following the continuous cutting and refinement of dislocation cells, subgrains, and fragmentation of the second precipitates. This study systematically clarified the mechanism of grain refinement and nanocrystallization on the surface of high-strength aluminum alloys and laid a theoretical foundation for further research on mechanical behavior and surface friction and wear properties of high-strength non-ferrous materials with gradient structure.
Road traffic can play an important role in strengthening regional economic activities, especially at high altitude, and it is necessary to know important traffic-related information. Although ...previous studies reported on road traffic in China, there has been little research on high-altitude road traffic to date.
The annual official census of road traffic safety from 2006 to 2013 was used to obtain data on the general population, registered drivers, registered vehicles, newly built roads, road traffic accidents (RTAs), mortality rate per 100 000 populations and per 10 000 vehicles in high-altitude provinces, including Tibet, Qinghai, Xinjiang, Gansu, Yunnan, Sichuan, and Chongqing. These provincial data were reviewed retrospectively, with the national data as the reference. Statistical analysis (i.e., t test) was used to compare the estimated average annual change rate of population, number of registered drivers, registered vehicles, and newly built roads in high-altitude provinces with the national rates.
Compared with the national data, there are significantly higher annual rates of population growth in Tibet and Xinjiang, registered drivers in Gansu, registered vehicles in Gansu, Sichuan, and Chongqing, and newly built roads in Tibet and Qinghai. Among the investigated provinces, Tibet, Qinghai, and Yunnan had a higher proportion of the roads with the high class. RTAs and RTA-induced casualties in the high-altitude provinces indicated a decreasing trend. The mortality rate per 10 000 vehicles and per 100 000 populations showed a decreasing trend, while the RTA-related mortality rate in Tibet, Qinghai, Xinjiang and Gansu remained high.
Major changes for road traffic in high-altitude provinces have occurred over the past decade; however, the RTA-related mortality rate in high-altitude provinces has remained high. This study furthers understanding about road traffic safety in China; further studies on road traffic safety at high altitude should be performed.
Abstract The sulfate reducing bacteria(SRB) is commonly attached to the surface of buried pipeline steel, and the electron shuttle in the corrosion medium can promote the release of electrons from ...iron oxidation through the bacterial cell wall into the cytoplasm to accelerate the corrosion of anode iron. This study investigated the impact of riboflavin (RF) as an endogenous electron shuttle on the corrosion behavior of X80 pipeline steel in SRB system. The findings indicated that while the type of corrosion products remains unchanged in samples under SRB+10 mg l −1 RF system, there was an expansion in both area and depth of corrosion pits on the sample surface, resulting in a corrosion loss rate approximately 3 times higher than that observed in SRB system. Furthermore, the polarization resistance (R p ) value of the sample in SRB system is about 2 ∼ 5 times that of the sample in SRB+10 mg l −1 RF system. Additionally, the corrosion current density of X80 pipeline steel samples soaked in SRB and SRB +10 mg l −1 RF system for 14 days is 9.31 × 10 -6 A·cm −2 and 1.28 × 10 −5 A·cm −2 , and the addition of 10 mg l −1 RF increases the corrosion current density of SRB system by about 37.49%. These results indicated that the reaction resistance of SRB-induced MIC in X80 pipeline steel was significantly reduced due to the presence of RF.
This study was conducted to evaluate the effects of feed form (mash and crumble-pellet) and feed particle size (fine, medium and coarse) on growth performance, carcass characteristics and digestive ...tract development of broilers. A total of 1,152 one day-old Ross 308 mixed-sex broilers were used in a factorial arrangement (2 × 3) based on a completely randomized design with six replicates of 32 birds each. Higher average daily gain (ADG) and average daily feed intake (ADFI) were observed (P < 0.01) for birds fed the crumble-pellet diets (CPD) than for those fed the mash diets (MD) during starter, grower and the entire experiment period. From d 1 to 40, birds fed CPD had a higher (P < 0.01) body weight (BW) than those fed MD. Birds fed CPD had a lower (P < 0.01) feed:gain ratio (F:G) during the starter phase than those fed MD. Medium or coarse particle size increased (P < 0.01) ADG and ADFI during the starter phase, but birds fed fine particle size diets had lower (P < 0.01) F:G during the grower phase. In MD, medium and coarse particle sizes resulted in higher (P < 0.05) BW, ADG and ADFI than fine particle size during the whole experiment. In CPD, particle size had no significant effect on growth performance, as indicated by a feed form × particle size interaction (P < 0.05). At 41 days of age, ten birds per treatment were randomly selected and killed for slaughter yields and digestive tract characteristics determination. It was shown that particle size and feed form alone had no significant effect on slaughter yields, so changes was the feed form × particle size interaction. The relative empty weight of the gizzard was greater (P < 0.01) and the relative length of the ileum was longer (P < 0.05) in birds fed MD than in those fed CPD. Overall, CPD improved growth performance during the entire period of the study with effects being less evident during the finisher phase than during the starter and grower phases, and the effect of feed particle size varied depending on feed form.
Direct-current electrical fields (EFs) promote nerve growth and axon regeneration. We report here that at physiological strengths, EFs guide the migration of neuronal stem/progenitor cells (NSPCs) ...toward the cathode. EF-directed NSPC migration requires activation of N-methyl-d-aspartate receptors (NMDARs), which leads to an increased physical association of Rho GTPase Rac1-associated signals to the membrane NMDARs and the intracellular actin cytoskeleton. Thus, this study identifies the EF as a directional guidance cue in controlling NSPC migration and reveals a role of the NMDAR/Rac1/actin signal transduction pathway in mediating EF-induced NSPC migration. These results suggest that as a safe physical approach in clinical application, EFs may be developed as a practical therapeutic strategy for brain repair by directing NSPC migration to the injured brain regions to replace cell loss. Disclosure of potential conflicts of interest is found at the end of this article.
Traffic medical research status Wang, Zhengguo
Chinese journal of traumatology,
04/2015, Volume:
18, Issue:
2
Journal Article
Peer reviewed
Open access
Since the first fatal car accident happened in London on August 17th 1896, more than 32 million people have died from car accidents which outnumber the total deaths caused by wars or natural ...disasters.
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