188 research outputs found

    Relationship between intrinsic viscosity, thermal, and retrogradation properties of amylose and amylopectin

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    The relationships between intrinsic viscosity and some properties of amylose and amylopectin were investigated. The intrinsic viscosities determined by Ubbelohde viscometer for rice, maize, wrinkled pea and potato amyloses were 46.28 ± 0.30, 123.94 ± 0.62, 136.82 ± 0.70, and 167.00 ± 1.10 ml/g, respectively; and the intrinsic viscosities of rice, maize, wrinkled pea and potato amylopectins were 77.28 ± 0.90, 154.50 ± 1.10, 162.56 ± 1.20 and 178.00 ± 1.00 ml/g, respectively. The thermal and retrogradation properties of amylose and amylopectin were investigated by differential scanning calorimeter (DSC). Results showed that the thermal enthalpy (ΔHg) was positively correlated with intrinsic viscosity, however, the onset and peak temperatures were not related to the intrinsic viscosity. The amylose and amylopectin retrogradation enthalpy values were negatively related to intrinsic viscosity, while the onset and peak temperature values of retrograded amylose and amylopectin were not related to the intrinsic viscosity during storage (except one-day storage). Furthermore, the onset and peak temperatures and retrogradation enthalpy of amylose and amylopectin changed slowly during storage at 4°C

    Survey on the Overwintering of Syrphids in Changbai Mountains and Experiments on Artificial Protection of the Overwintering Syrphid Flies

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    Originating text in Chinese.Citation: Gao, Junfeng, Zhang, Guangxin, Qin, Yongchun, Yu, Kai, Li, Minghai, Qin, Yi. (1993). Survey on the Overwintering of Syrphids in Changbai Mountains and Experiments on Artificial Protection of the Overwintering Syrphid Flies. Chinese Journal of Biological Control, 9(3), 142-144

    Direct conversion of astrocytes into neuronal cells by drug cocktail

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    Direct conversion of astrocytes into neuronal cells by drug cocktail Cell Research advance online publication 2 October 2015; doi:10.1038/cr.2015.120 Dear Editor, Neurological disorder is one of the greatest threats to public health according to the World Health Organization. Because neurons have little or no regenerative capacity, conventional therapies for neurological disorders yielded poor outcomes. While the introduction of exogenous neural stem cells or neurons holds promise, many challenges still need to be tackled, including cell resource, delivery strategy, cell integration and cell maturation. Reprogramming of fibroblasts into induced pluripotent stem cells or directly into desirable neuronal cells by transcription factors (TFs) or small molecules can solve some problems, but other issues remain to be addressed, including safety, conversion efficiency and epigenetic memory [1, 2]. Astrocytes are considered to be the ideal starting candidate cell type for generating new neurons, due to their proximity in lineage distance to neurons and ability to proliferate after brain damage. Many studies have already revealed that astrocytes of the central nervous system can be reprogrammed into induced neuronal cells by virus-mediated overexpression of specific TFs in vitro and in vivo [3-6]. However, application of this virus-mediated direct conversion is still limited due to concerns on clinical safety. We have previously reported direct conversion of somatic cells into neural progenitor cells (NPCs) in vitro by cocktail of small molecules under hypoxia [7]. Here we set out to explore whether astrocytes can be induced into neuronal cells by the chemical cocktail in vitro

    Numerical Investigation of Storage Behaviors of A Liquid CO2 Tank

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    The dynamic behavior of heat transfer induced by flow of the storage tank during the storage process was investigated using the computational fluid dynamics (CFD) approach, with the target of the liquid CO2 storage tank in a CO2 injection station in an oilfield. The flow field distribution outside the tank was simulated, exhibiting the patterns of air flow near the tank wall. The effect of progressive cooling leakage in the tank under various conditions was determined through simulation of the dynamic of flow heat transfer under various storage settings, with the result indicating that tank pressure has a beneficial effect on cooling capacity. The medium level, on the other hand, had a negative impact on cooling capacity. Finally, the impact of environmental variables on fluid loss was evaluated. This finding supports the safety and cost-benefit analysis of liquid CO2 storage systems

    Dust emission reduction enhanced gas-to-particle conversion of ammonia in the North China Plain

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    Liu et al. found that the formation rate of particulate ammonium is slower in the atmosphere than that observed in the laboratory, while it is sped up due to an increase in aerosol acidity driven by an emission reduction of dust in North China Plain.Ammonium salt is an important component of particulate matter with aerodynamic diameter less than 2.5 mu m (PM2.5) and has significant impacts on air quality, climate, and natural ecosystems. However, a fundamental understanding of the conversion kinetics from ammonia to ammonium in unique environments of high aerosol loading is lacking. Here, we report the uptake coefficient of ammonia (gamma(NH3)) on ambient PM2.5 varying from 2.2 x 10(-4) to 6.0 x 10(-4) in the North China Plain. It is significantly lower than those on the model particles under simple conditions reported in the literature. The probability-weighted gamma(NH3) increases obviously, which is well explained by the annual decrease in aerosol pH due to the significant decline in alkali and alkali earth metal contents from the emission source of dust. Our results elaborate on the complex interactions between primary emissions and the secondary formation of aerosols and the important role of dust in atmospheric chemistry.Peer reviewe

    Hydrogen injection reduces ammonia nitrogen and changes microbial community composition in aquaculture water

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    The study aimed to investigate the effect of hydrogen on nitrogen and phosphorus removal and microbial community composition in aquaculture water. Two groups were designed separated: Group H was charged with hydrogen and Group D was set as control. Water samples were collected at 0, 1, 2, 3, 4, 5, 6, and 7 days after hydrogen injection to detect not only the content of total nitrogen, ammonia nitrogen and phosphorus, but also microbial community composition in aquaculture water. Our findings have demonstrated that 7-days’ hydrogen treatment could effectively reduce ammonia nitrogen in aquaculture water. And in Day 7, the concentration of ammonia nitrogen in Group D was 1.66 times as that in Group H. Meanwhile, microbial structures in the water bodies of these two groups were significantly different. The abundance of bacteria such as Proteobacteria, Firmicutes, Bacteroidetes, and Desulphuria increased clearly in Group H, which means nitrification and denitrification occurred in the effect of hydrogen injection. These findings suggested that hydrogen could significantly improve aquaculture water health and reduce the production of ammonia nitrogen, which means hydrogen could be used as a functional external method to protect the aquaculture environment

    Deposition potential of 0.003-10 mu m ambient particles in the humidified human respiratory tract : Contribution of new particle formation events in Beijing

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    Ultrafine particles (UFPs) usually explosive growth during new particle formation (NPF) events. However, the risk of exposure to UFPs on NPF days has been ignored due to the prevalence of mass-based air quality standards. In this study, the daily deposited doses, i.e., the daily deposited particle number dose (D-PNd), mass dose (D-PMd), and surface area dose (D-PSd), of ambient particles in the human respiratory tract in Beijing were evaluated based on the particle number size distribution (3 nm-10 mu m) from June 2018 to May 2019 utilizing a Multiple-Path Particle Dosimetry Model (MPPD) after the hygroscopic growth of particles in the respiratory tract had been accounted for. Our observations showed a high frequency (72.6%) of NPF on excellent air quality days, with daily mean PM2.5 concentrations less than 35 mu g m(-3). The daily D-PNd on excellent air quality days was com-parable with that on polluted days, although the D-PMd on excellent air quality days was as low as 15.6% of that on polluted days. The D-PNd on NPF days was similar to 1.3 times that on non-NPF days. The D-PNd in respiratory tract regions decreased in the order: tracheobronchial (TB) > pulmonary (PUL) > extrathoracic (ET) on NPF days, while it was PUL > TB > ET on non-NPF days. The number of deposited nucleation mode particles, which were deposited mainly in the TB region (45%), was 2 times higher on NPF days than that on non-NPF days. Our results demonstrated that the deposition potential due to UFPs in terms of particle number concentrations is high in Beijing regardless of the aerosol mass concentration. More toxicological studies related to UFPs on NPF days, especially those targeting tracheobronchial and pulmonary impairment, are required in the future.Peer reviewe

    KovĂĄcs MihĂĄly Ă©s a kibernetika oktatĂĄs kezdetei a budapesti Piarista gimnĂĄziumban

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    Genotype-specific transcriptional DEGs results in resistant genotype and susceptible genotype. (XLSX 4357 kb

    Unprecedented Ambient Sulfur Trioxide (SO3) Detection : Possible Formation Mechanism and Atmospheric Implications

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    Sulfur trioxide (SO3) is a crucial compound for atmospheric sulfuric acid (H2SO4) formation, acid rain formation, and other atmospheric physicochemical processes. During the daytime, SO3 is mainly produced from the photo-oxidation of SO2 by OH radicals. However, the sources of SO3 during the early morning and night, when OH radicals are scarce, are not fully understood. We report results from two field measurements in urban Beijing during winter and summer 2019, using a nitrate-CI-APi-LTOF (chemical ionization-atmospheric pressure interface-long-time-offlight) mass spectrometer to detect atmospheric SO3 and H2SO4. Our results show the level of SO3 was higher during the winter than during the summer, with high SO3 levels observed especially during the early morning (similar to 05:00 to similar to 08:30) and night (similar to 18:00 to similar to 05:00 the next day). On the basis of analysis of SO2, NOx, black carbon, traffic flow, and atmospheric ions, we suggest SO3 could be formed from the catalytic oxidation of SO2 on the surface of traffic-related black carbon. This previously unidentified SO3 source results in significant H2SO4 formation in the early morning and thus promotes sub-2.5 nm particle formation. These findings will help in understanding urban SO3 and formulating policies to mitigate secondary particle formation in Chinese megacities.Peer reviewe
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