云杉针叶的扫描电镜观察

本文应用扫描电子显微镜,对针叶树云杉的针叶进行了表面结构的观察。结果表明,云杉针叶表面有较厚的角质层,角质层呈条纹状排列。从横切面上看,针叶为四角形,叶的四面均有气孔。云杉的气孔下陷,呈蜂窝状,叶表皮具有瘤状突起物, 这些构造特征,都有利于减少植物体水分的散失。通过对云杉这些结构的观察研究。可以为它的品种改良提供依据。     

Effects of alterations of the amino-terminal glycine of influenza hemagglutinin fusion peptide on its structure, organization and membrane interactions

Mutations of the glycine residue at the amino terminus of HA2 have been shown to have a large effect on the fusion activity of HA2, the extent of which apparently correlates with the side chain bulkiness of the substituting amino acids. To investigate into the cause of abrogation in fusogenicity and virus-promoted fusion mechanism, we synthesized several peptides in which this glycine was substituted by serine, glutamic acid, or lysine. 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl sn-glycero-3-phosphoglycerol (DMPG) were used as model membranes in the fluorescence, circular dichroism (CD), and FTIR measurements while sodium dodecyl sulfate was used in NMR studies. We found that, for the less active variants, affinity to membrane, degree of solvent dehydration, lipid perturbation, depth of insertion, and helicity were less. Comparison of affinity to membrane bilayer among these analogs revealed that binding of the fusion peptide is determined largely by the hydrophobic effect. Additionally, the orientation is closer to the membrane normal for the wild-type fusion peptide in the helix form while the inactive analogs inserted more parallel to the membrane surface.     

Mechanical phenotyping of stem cells

Elasticity and visco-elasticity are mechanical properties of cells which directly reflect cellular composition, internal structure (cytoskeleton), and external interactions (cell-cell and/or cell-surface). A variety of techniques involving probing, pulling, or deforming cells have been used to characterize these mechanical properties. With continuing advances in the technology, it may be possible to establish mechanical phenotypes that can be used to identify cells at specific points of differentiation and dedifferentiation with direct applications to regenerative medicine, therapeutics, and diagnostics.     

ARFI应用中射频及嵌入深度对肝脏弹性成像诊断准确性的影响

目的:分析应用声辐射力脉冲成像(Acoustic Radiation Force Impulse Imaging,ARFI)技术进行肝病诊断过程中不同探针及不同嵌入深度对其诊断准确性的影响。方法:于2012~2014年,选取经ARFI诊断过的98例丙型肝炎(Hepatitis C Virus,HCV)患者,对两种探针(凸阵探头C4-1 MHz和线阵探头L9-4 MHz)诊断下的相关数据进行前瞻性研究分析,并与瞬时弹性成像(Fibroscan)进行对比。对不同嵌入深度的ARFI弹性成像的变异性进行了系统评估。结果:根据Fibroscan成像结果,33例患者(34%)患有肝硬化,其余患者中27例(27%)患有严重的肝纤维化,38例(39%)未患。C4-1的传播速率平均为1.68±0.59 m/s,L9-4为1.93±0.76 m/s。两种探针检测结果彼此相关显著(P0.001,r=0.71),且二者均与Fibroscan结果显著相关(P0.001,r分别为0.79和0.81)。对于肝硬化或严重肝纤维化患者而言,L9-4探针诊断结果高于C4-1探针,差异具有统计学意义(P0.001)。在诊断肝硬化疾病中,C4-1和L9-4探针的AUROC值分别为0.97和0.91,截断水平分别为1.68和2.01 m/s。C4-1和L9-4嵌入深度分别为3~6 cm和2~3.5 cm。结论:线阵探头和凸阵探头在应用ARFI成像评估肝脏硬度中具有较高的准确性,相较而言,线阵探头诊断结果更高。且ARFI的测量操作不宜靠近肝被膜。     

Aquatic Biofouling Larvae Respond to Differences in the Mechanical Properties of the Surface on which they Settle

Surface energy has been proposed to explain the resistance of dimethyl silicones (DMS) to biofouling, but surface energy considerations alone cannot explain all the data. Because the crosslinking density of a polymer influences its elastic modulus, biofouling on DMS substrata that differ in degree of crosslinking was studied. In addition to the recently described easier release of adult macrofouling, decreasing the elastic modulus between about 0.01-0.1 kPa significantly decreased larval settlement of three groups of test organisms. It is hypothesized that larvae sense variations in elastic modulus by deformation of sensory membranes, which causes changes in mechanosensitive ion channels.     

计算强激光作用下生物组织中烧蚀深度的新公式

本文采用强激光对生物组织热作用的一维Stefan数学模型和反问题辨识方法,并充分考虑实际多维问题的复杂性,提出了确定强激光作用下烧蚀深度的计算关系式。由该公式得出的理论计算结果与实验数据符合得较好。     

Mechanical understanding of hunting waves generated by killer whales

The wave wash hunting employed by Orcinus orca, also known as killer whales, is unique in that the prey is hunted outside of the water by generating waves. To quantitatively analyze the specific mechanism of the wave wash, data were obtained using computational fluid dynamics (CFD), and wave theory was introduced as the theoretical background to clarify the mechanism. The relationships between the swimming characteristics and wave parameters are defined in this paper. The results obtained by numerical investigation revealed that the wavelength increased with the swimming speed. Additionally, the wave height increased as the swimming speed increased and the swimming depth became shallower, and subsequently converged to a maximum of 2.42 m. The success of hunting is determined by two wave parameters, which indicate the intensity of the wave wash: the wave height and force exerted on the prey. The metabolic rate and the drag force are considered to evaluate the efficiency of the locomotion, which varied according to the swimming speed (V) and swimming depth (d) of the whales. To generate hunting waves efficiently, the optimal ranges of V and d were estimated to be 3 ~ 5 m/s and 0.5 m ~ 1.1 m respectively.     

Variability in the distribution and composition of insertion sequence-like elements in strains of Mycoplasma fermentans

Mycoplasma fermentans has been reported to be pathogenic for man. All fourteen strains tested contain an insertion sequence-like element (ISLE) which may be present in multiple copies. To determine whether ISLE copies are similarly distributed in different strains of M. fermentans, restriction enzyme digest fragments of genomic DNA from 14 isolates, from a variety of sources, were separated by electrophoresis, blotted and hybridized to a biotin labelled polymerase chain reaction (PCR) amplified fragment of ISLE. A range of patterns was observed suggesting that the element has a tendency to undergo rearrangement within the genome. Analysis of ISLE sequences revealed inter- and intra-strain polymorphisms.     

Identification of causal effects using instrumental variables in randomized trials with stochastic compliance

In randomized trials with imperfect compliance, it is sometimes recommended to supplement the intention‐to‐treat estimate with an instrumental variable (IV) estimate, which is consistent for the effect of treatment administration in those subjects who would get treated if randomized to treatment and would not get treated if randomized to control. The IV estimation however has been criticized for its reliance on simultaneous existence of complementary “fatalistic” compliance states. The objective of the present paper is to identify some sufficient conditions for consistent estimation of treatment effects in randomized trials with stochastic compliance. It is shown that in the stochastic framework, the classical IV estimator is generally inconsistent for the population‐averaged treatment effect. However, even under stochastic compliance, with certain common experimental designs the IV estimator and a simple alternative estimator can be used for consistent estimation of the effect of treatment administration in well‐defined and identifiable subsets of the study population.     

Insertion reactions of organic anhydrides and the Cu(I) alkoxide [CuOBu]

The synthesis and structural characterization of the copper salts [Cu₈(benzoate)₈(THF)₆] (1), [Cu₂{(CO₂)₂C₆H₂(Boc)₂}dppm₂]₂ (2) and [Cu₂{(CO₂)₂C₁₀H₄(Boc)₂}dppm₂]₂ (3) [Boc = tert-butoxycarbonyl, dppm = 1,2-bis(diphenylphosphino)methane] prove that cyclic organic anhydrides and dianhydrides readily insert into the Cu-O bond of [CuO^tBu] forming carboxylate ligands with ester functionalities in the ligand periphery. [Mn₃(o-Boc-benzoate)₆(DME)₂] (4) (DME = 1,2-dimethoxyethane) was synthesized by the metathesis reaction of [Cu(I)(o-Boc-benzoate)] with MnCl₂.     

Application of the quasi-spectral density function of 15N nuclei to the selection of a motional model for model-free analysis

Summary Parameters used in model-free analysis were related to simulated spectral density functions in a frequency region experimentally obtained by quasi-spectral density function analysis of ¹⁵N nuclei. Five kinds of motional models used in recent model-free analyses were characterized by a simple classification of the experimental spectral density function. We demonstrate advantages and limitations of each of the motional models. To verify the character of the models, model selection using experimental spectral density functions was examined.     

Random insertion mutagenesis of the intracellular pathogen Rhodococcus equi using transposomes

The identification of virulence factors in Rhodococcus equi has been severely hampered by the lack of a method for in vivo random insertion mutagenesis. This study reports the use of transposomes to generate random insertions of a gene conferring kanamycin resistance into the genome of R. equi ATCC 33701. Southern hybridisation using the kanamycin resistance gene as probe showed that insertion of transposome is random. This was confirmed following nucleotide sequence analysis of the junction between the transposome and chromosomal DNA. The presence of a 9 bp duplication of the target sequence showed that random integration of the transposome was due to a bona fide Tn5 transposition event.     

多性状综合遗传效应测定方法的研究

应用主成分分析原理提出测定多个交配组合多性状综合遗传效应的方法,将多性状综合遗传效 各主成分遗传效应与其相对重要树重乘积和,此法消除了性状间相关和环境因素的影响,得到的多性状综合遗传效应可以互相比较,便于选出最佳交配组合用于动物生产。     

超声引导经皮微波消融治疗邻近血管的原发性肝癌的疗效分析

探讨超声引导经皮微波消融治疗邻近血管的原发性肝癌的疗效。2010年1月至2013年6月期间,回顾性分析在我院采用超声引导下微波消融技术治疗的213例(267个病灶)原发性肝癌患者的病例资料,根据患者病灶位置分为邻近血管组(76例,91个病灶)和对照组(137例,176个病灶),比较两组患者的微波消融次数、微波消融时间、完全消融率、局部肿瘤进展率、累计存活率及并发症。邻近血管组和对照组的原发性肝癌患者消融次数均为1~3次,两组平均微波消融次数无显著差异(p<0.05)。两组微波消融时间为5~28 min,其中邻近血管组显著高于对照组(p>0.05)。微波消融1个月后,邻近血管组的完全消融率与对照组无显著差异(p<0.05)。两组患者在3个阶段(1随访1年,3年和5年)的的局部肿瘤进展率和累计生存率无统计学差异(p<0.05)。两组患者5年随访时间内分别有29例和53例患者死亡。主要死亡原因包括肝癌进展、肝功能衰竭、血管曲张破裂、脑出血、急性肺栓塞、心肌梗死等。邻近血管组共有25例出现术后并发症,对照组有44例。主要并发症类型为腹腔积液、膈疝、出血、肝脓肿、气胸、肝区疼痛和发热。两组之间并发症发生率无统计学意义(p=0.907)。微波消融治疗邻近血管的原发性肝癌具有较好的局部肿瘤控制率,可对邻近血管的危险病灶区域进行有效治疗。     

Insertion reactions of organic anhydrides into the M-O bond of CuOBu and Sb(OMe)3

The synthesis and structural characterization of the copper salts [Cu₂(2-Boc-benzoate)₄(dme)₂] (1), [Cu(2-Boc-benzoate)₂(tmeda)] (2), [Cu₂(2-Boc-benzoate)₂(dppm)] (3), [Cu(2-Boc-nicotinate)(PPh₃)₂] (4), [Cu₂{2-Boc-5,6-anhydride-naphthylcarboxylate}₂(dppm)₂] (5) [dme = 1,2-dimethoxyethane, dppm = bis(diphenylphosphino)methane, tmeda = N,N′-tetramethylethylenediamine, Boc = tert-butoxycarbonyl] prove that cyclic organic anhydrides and dianhydrides readily insert into the Cu-O bond of [CuO^tBu] forming carboxylate ligands with ester functionalities in the ligand periphery. [Sb(CO₂Ph-o-CO₂Me)₂(OMe)(tmeda)] (6) was synthesised by insertion reaction of Sb(OMe)₃ with phthalic anhydride.     

瑞香属植物生物活性研究进展

瑞香属植物分布广泛,在我国有35种。其中一些种类自古即供药用、观赏和作造纸原料。近几十年来,人们已从瑞香属植物中发现了60多种具不同作用的生物活性物质。药理学和毒理学研究表明,这些活性物质中,有的抗HIV、白血病、血栓形成和动脉粥样硬化,有的可抑制铜绿假单孢菌、细菌和疟原虫感染,有的可用于临床引产,还有的具杀虫和抑菌作用。说明这是一个大有开发前途的植物类群。