水稻苗期抗寒性的杂种优势分析

通过观察12个水稻杂交组合(包括父母本)的苗期叶片的相对电导率和植株的成苗率,来探讨水稻苗期抗寒性的杂种优势.分析表明:在经过4℃、2 d的冷处理后,12个杂交组合的相对电导率的超亲优势值都为负数,中亲优势值在-37.27%～+21.02%之间,成苗率在-30.80%～+7.20%之间,杂种优势表现为中亲优势.     

新型人工红细胞的制备

目的:接枝淀粉包裹血红蛋白制备新型人造红细胞的代替品。方法:利用油酸接枝淀粉,在超声条件下下自组装,包裹天然牛血红蛋白,并鉴定其物理化学及生物学性能。测定包封率、红外光谱分析(FTIR)、电镜观察形态学及粒径,测定P50和Hill系数。结果:人工红细胞呈圆球形,平均粒径250nm,包封率高,具有良好的携氧、释氧能力。结论:成功制备了人工纳米红细胞,为进一步临床应用提供了基础。     

壳聚糖接枝改性PET 人工韧带的表面结构与特性研究

目的:于聚对苯二甲酸乙二醇酯(PET)人工韧带材料表面接枝壳聚糖长链分子,对改性PET人工韧带的表面结构与特性进行分析,以期为较好生物相容性的PET人工韧带材料的设计和研发奠定一定的理论基础和技术支持。方法:首先采用化学接枝法在聚对苯二甲酸乙二醇酯(PET)织物表面接枝丙烯酸(PET-AAc),再与壳聚糖分子发生酰胺化反应实现PET表面的壳聚糖接枝(PET-CHI)。借助接触角、x射线光电子能谱(XPS)、傅立叶红外光谱(FTIR)、热失重(TG)和扫描电镜(SEM)等对PET改性效果进行分析表征。结果:壳聚糖长链分子成功接枝到PET表面,壳聚糖在PET表面的接枝厚度为2.25μm,接枝量为9.66 wt%。结论:接枝改性后PET表面亲水性有较大提高,浸润性得到改善。     

Mammalian cell protein expression for biopharmaceutical production

Mammalian cell expression has become the dominant recombinant protein production system for clinical applications because of its capacity for post-translational modification and human protein-like molecular structure assembly. While expression and production have been fully developed and Chinese hamster ovary cells are used for the majority of products both on the market and in clinical development, significant progresses in developing and engineering new cell lines, introducing novel genetic mechanisms in expression, gene silencing, and gene targeting, have been reported in the last several years. With the latest analytical methods development, more attention is being devoted towards product quality including glycol profiling, which leads to better understanding the impact of culture condition during production. Additionally, transient gene expression technology platform plays more important role in biopharmaceutical early development stages. This review focused on the latest advancements in the field, especially in active areas such as expression systems, glycosylation impact factors, and transient gene expression.     

Favoring the birth of female puppies after artificial insemination using chilled semen diluted with powdered coconut water (ACP-106c)

The objective was to determine the effect of powdered coconut water extender (ACP-106c) on the proportion of female puppies born. Twenty French Bulldog bitches were subjected to natural mating (NM) and, during the subsequent two estrus periods, were bred by intravaginal artificial insemination (AI), using chilled semen (from the same males) diluted in Tris-egg yolk (AI-Tris) or ACP-106c (AI-ACP-106c). Fresh semen was cooled to 5 °C and maintained at that temperature for 6 h, rewarmed (37 °C for 30 s), and used for AI. Pregnancy and whelping rates following NM were both 100% and were both 90.0% following AI with either extender. Litter size (mean ± SD) was 5.4 ±1.1, 4.7 ± 2.0, and 5.1 ± 2.0 (P > 0.05) for NM, AI-Tris, and AI-ACP-106c, respectively. Furthermore, for these groups, the number of female vs. male puppies born were 2.6 ± 0.6 vs. 2.8 ± 1.0, 2.2 ± 1.0 vs. 2.5 ± 1.1, and 3.4 ± 1.6 vs. 1.8 ± 1.2 (P < 0.05 for AI-ACP-106c only). In conclusion, our hypothesis was supported; AI of semen in ACP-106c extender resulted in a significantly higher proportion of female puppies. Furthermore, this extender yielded acceptable litter size and rates of pregnancy and whelping.     

Pregnancy rates in mares inseminated with 0.5 or 1 million sperm using hysteroscopic or transrectally guided deep-horn insemination techniques

Placement of sperm deep in the equine uterine horn allows fewer sperm to be inseminated while maintaining acceptable fertility, and has been promoted for use in circumstances when fertility would be expected to be low if standard insemination were used (e.g., semen from a subfertile stallion, or frozen-thawed semen). Two main techniques, transrectally guided (TRG) and hysteroscopic (HYS) insemination, have been developed for this purpose; however, there is some controversy regarding their comparative efficacy. This study was conducted to compare pregnancy rates when mares were inseminated by TRG or HYS, using sperm numbers approaching and under the minimum threshold, resulting in reduced fertility. When 1 × 10⁶ sperm were inseminated, pregnancy rates were not different (P > 0.10) between techniques HYS (10/13, 77%) and TRG (11/15, 73%). Similarly, when 0.5 × 10⁶ sperm were inseminated, pregnancy rates were not different (P > 0.10) between techniques HYS (3/15, 20%) and TRG (4/13, 31%). Combined pregnancy rates for the two treatments were 13/28 (46%) for HYS and 15/28 (54%) for TRG (P > 0.10). Pregnancy rates using a subthreshold number of sperm were not significantly affected by a deep-horn insemination technique.     

Energetics and forces of the Dionaea muscipula trap closing

The Venus flytrap is the most famous carnivorous plant. The electrical stimulus between a midrib and a lobe closes the Venus flytrap upper leaf in 0.3 s without mechanical stimulation of trigger hairs. Here we present results for direct measurements of the closing force of the trap of Dionaea muscipula Ellis after mechanical or electrical stimulation of the trap using the piezoelectric thin film or Fuji Prescale indicating sensor film. The closing force was 0.14 N and the corresponding pressure between rims of two lobes was 38 kPa. We evaluated theoretically using the Hydroelastic Curvature Model and compared with experimental data velocity, acceleration and kinetic energy from the time dependencies of distance between rims of lobes during the trap closing. The Charge Stimulation Method was used for trap electrostimulation between the midrib and lobes. From the dependence of voltage between two Ag/AgCl electrodes in the midrib and one of the lobes, we estimated electrical charge, current, resistance, electrical energy and electrical power dependencies on time during electrostimulation of the trap.     

Occupational exposure to electric fields and currents associated with 110 kV substation tasks

The main aim of this study was to investigate occupational exposure to electric fields, and current densities and contact currents associated with tasks at air-insulated 110 kV substations and analyze if the action value of EU Directive 2004/40/EC was exceeded. Four workers volunteered to simulate the following tasks: Task (A) maintenance of an operating device of a disconnector at ground or floor level, Task (B) maintenance of an operating device of a circuit breaker at ground or floor level, Task (C) breaker head maintenance from a man hoist, and Task (D) maintenance of an operating device of a circuit breaker from a service platform. The highest maximum average current density in the neck was 1.8 mA/m(2) (calculated internal electric field 9.0-18.0 mV/m) and the highest contact current was 79.4 μA. All measured values at substations were lower than the limit value (10 mA/m(2)) of the EU Directive 2004/40/EC and the 2010 basic restrictions (0.1 and 0.8 V/m for central nervous system tissues of the head, and all tissues of the head and body, respectively) of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).     

Comparison of complex permittivities of isotonic colloids containing single‐wall carbon nanotubes of varying chirality

The application of bio‐compatible, conductive nanoparticles in combination with radiofrequency (RF) irradiation to raise tissue temperatures between 40 and 60 °C for hyperthermia and ablation spurred interest in the complex permittivities of isotonic nanoparticle‐based colloids. Nanoparticles with large aspect ratios and high permittivities increase the bulk permittivity of the colloid and RF losses at the macroscopic scale. The complex permittivities of isotonic colloids with and without single‐wall carbon nanotubes (SWCNTs) containing either metallic, semiconducting, or mixed chiralities were measured from 20 MHz to 1 GHz at room temperature. The colloids were made with one of three different isotonic solvents: phosphate buffered saline (PBS), and Dulbecco's modified eagle medium (DMEM) with and without 0.5% weight/volume bovine serum albumin to simulate cytosol and blood, respectively. The concentration of elemental carbon from the SWCNTs in the colloids ranged from 16 to 17 mM. The permittivities were corrected for electrode polarization effects by fitting the data to the Cole–Cole relaxation model with a constant phase angle element. The presence of SWCNTs increased both the real and imaginary components of the permittivities of the colloids. For all three solvents, the direct current (DC) components of the real and imaginary permittivities were greatest for the colloids containing the mixed chirality SWCNTs, followed by the colloids with semiconducting SWCNTs, and then metallic SWCNTs. Bioelectromagnetics 33:134–146, 2012. © 2011 Wiley Periodicals, Inc.