Amino acid requirements for maturation of rhesus monkey (Macacca mulatta) oocytes in culture

This study evaluated the effects of different amino acid formulations on supporting meiotic and cytoplasmic maturation of rhesus monkey (Macacca mulatta) oocytes in vitro. Five hundred and forty-six cumulus-oocyte complexes (COCs) aspirated from unstimulated adult monkey follicles (greater than or equal to 1000 mum in diameter) were cultured in either modified Connaught Medical Research Laboratories 1066 medium (mCMRL-1066) or in one of eight chemically defined media (modified basic medium 5 supplemented with 5.5 mmol glucose l(-1), 0.003 mmol pantothenic acid l(-1) and different amino acid formulations) as below: (1) modified basic medium 5 (mBM5) containing no amino acid; (2) mBM5 + 0.2 mmol glutamine l(-1); (3) mBM5 + 11 amino acids from hamster embryo culture medium 6 (HECM-6) (11 AA); (4) mBM5 + Eagle's non-essential amino acids (NEA); (5) mBM5 + NEA + 0.2 mmol glutamine l(-1); (6) mBM5 + Eagle's essential amino acids (EA) without glutamine; (7) mBM5 + EA + 0.2 mmol glutamine l(-1); (8) mBM5 + Eagle's 20 amino acids (20 AA) + 0.2 mmol glutamine l(-1); and (9) mCMRL-1066 (control). All media contained FSH, LH, oestradiol and progesterone. After maturation, mature oocytes were subjected to the same fertilization and embryo culture procedures. COCs matured in treatment 5 had greater potential to progress to metaphase II (66%; P < 0.05) than did those in treatments 1 (37.3%), 2 (48.3%)f 3 (41%), 6 (41%) and 9 (43%). Oocytes matured in treatment 8 had the best morula (53%) and blastocyst (18%) developmental responses (P<0.05). The lowest (P<0.05) morula and blastocyst developmental responses were obtained from COCs matured in treatments 1 (0%) and 6 (8%). The other media supported intermediate embryonic development (range 11-38% of morula and blastocyst). These results indicate that the choice of amino acids affects the competence of oocyte maturation and that Eagle's 20 AA with 0.2 mmol glutamine l(-1) is more efficient than the other amino acid formulations for maturation of rhesus monkey oocytes.

由（双氯代酞酰亚胺）与双酚盐的亲核取代缩聚合成聚酰亚胺的研究

利用邻苯二甲酸酐中苯环上的取代基由于受到两个羰基的吸电子作用有较好的活性，进行亲核取代反应合成聚酰亚胺近年来才引起人们的注意。根据这个反应可以从邻苯二甲酸酐出发，与双酚缩合先合成二酐单体，再与二胺反应合成易加工而性能良好的聚酰亚胺，而且已实现了工业生产。同时也可以从双取代酞酰亚胺出发直接与双酚进行亲核取代缩聚合成相同结构的聚酰亚胺。后者较前者具有合成路线短的优点，又无前者由于多种会反应所引起复杂分子链结构等缺点。文献上对双（硝基酞酰亚胺）与双酚的亲核取代缩聚反应合成聚酰亚胺的研究工作，有一些报导，而对双（氯代酞酰亚胺）与双酚A的亲核取代缩聚亦有专利，从文献报导来看，亲核取代缩聚法合成聚酰亚胺因反应条件要求苛刻，利用此法还不易合成出分子量高的聚合物。如何克服上述缺点，解决合成上的问题，是很有意义的。我们以双酚A与双（4－氯代酞亚胺）二苯醚的亲核取代缩聚反应为重点，采用NaOH溶液成盐的方法进行双（氯代酞酰亚胺）与双酚的亲核取代缩聚合成聚酰亚胺的研究。对影响反应的各种参数，如碱量，温度、固含量，溶剂，代水剂以及水份等对反应的影响，作了比较详细的探索，提出了从双（氯代酞酰亚胺）与双酚出发，用NaOH溶液成盐，通过亲核取代缩聚反应合成聚酰亚胺的比较合适的条件。研究了几种具有代表性的不同结构的双酚分别与双（4－氯代酞酰亚胺）二苯醚和双（3－氯代酞酰亚胺）二苯醚的亲核取代缩聚反应，所得结果表明，在相同的反应条件下，反应的难易一般取决于苯氧负离子的电子密度，和反应中心上正电荷对电子的吸引力，以及聚合物的溶解性。双酚A不仅其氧负离子有很强的亲核性，而且所得聚合的溶解性能也很好，照理应能很好地进行反应，但无论从我们的工作或文献上报导的结果来看，用惯常方法，以NaOH溶液成盐，从双酚A很难得比浓对数粘度较高的聚合物（美国专利从双（氯代酞酰亚胺）出发，合成的双酚A型聚酰亚胺的比浓对数粘度为0.21分升／克，美国General Electric Compang从双（硝茎酞酰亚胺）二苯醚与双酚A缩聚反应所得聚合物的比浓对数粘度是0.23分升／克）。我们从电子密度大的苯氧基虽有较强的亲核能力，但也同时具有较强的与反体系中微量水份形成氢键的能力出发考虑，认为解决问题的关键在于如何使体系中微量水份排除尽，为此我们采用两次代水方法，效果较为明显，使双酚A与双（4－氯代酞酰亚胺）二苯醚缩聚所得聚合物的比浓对数粘度达到0.4分升／克（DMAC，30℃），在此条件下，研究了不同结构的单体的构聚和共聚反应，所合成的一系列均聚和共聚物比浓和粘度在0.4～0.7分升／克范围，且通过共聚可以改善聚合物的溶解性，改进反应情况。在此基础上，我们又对双酚A与双（4－氯代酞酰亚胺）二苯醚的缩聚反应，用NaOH溶值成盐进行了五次代水实险，所得聚合物的分子量又得到进一步提高，其比浓对数粘度达到0.59分升／克。这些研究结果说明我们上述分析是正确的，同时也说明，双氯单体的活是不及双硝基单体，但在我们提出的实验条件下，反应也能很好的进行，而且此种方法没有双硝基单体与酚盐取代反应后所释放的亚硝酸盐所易引起的会反应。我们对所合成的各种不同结构的聚酰亚胺分别利用红外，核磁，X－射线，裂解色谱等进行了结构上的初步分析和探讨。不同结构的聚酰亚胺的红外光谱的显示出所合的聚合物特征峰，结合元素分析结果，并参照合成反应的基本原理证实了所合成的聚酰亚胺的化学结构与所予期的相符。在红外光谱上也初步鉴别了3们异构体聚酰亚胺和4位异构体聚酰亚胺。用~(13)C-NMR对本法所合成的溶解性较好的4种不同结构的聚酰亚胺进行表征，进一步证实了所得聚合物的化学结构，其中两种聚酰胺的~(13)C-NMR谱图与最近文献报导的从双（硝基酞酰亚胺）二苯醚与双酚A进行亲核取代缩聚所得相同结构的聚酰亚胺的~(13)C-NMR表征结果一致。~(13)C-NMR，~1C-NMR鉴定结果还表明利用双(酞酰亚胺)一醚虽需较高温度条件下进行取代缩聚反应，而聚合物的化学结构没有受到破坏。~(13)C-NMR也证明了从双（3－氯代酞酰亚胺）二苯醚出发所合成的聚合物的化学结构。用X－射线对不同结构的聚酰亚胺均聚物和共聚物进行结晶性的初步鉴定，其中由双酚醚和联苯双酚分别与双（4－氯代酞酰亚胺）二苯醚的缩聚产物具有一定程度的结晶，并通过DSC析测发现结晶熔融吸热峰予以进一步证实。普通X－射线鉴定结果对3位和4位异构聚酰亚胺的溶解性能上的差异作出解释。对不同结构的聚酰亚胺用居里点裂解器进行裂解色谱的初步研究和探讨，通过主要裂解产物进一步证明所合成的聚合物的化学结构，并讨论了裂解过程和机理。对各种不同结构的均聚和共聚聚酰亚胺进行溶解性及热稳定性的研究，并与从二胺和二酐出发合成的聚酰亚胺进行比较。亲核取代缩聚法所合成的聚酰胺不仅均有较明显的玻璃化转变，而且也有较好的溶解性能。从二酐与二胺所得相同结构的聚酰亚胺溶解性能不好，可能是由于在热处理环化过程中不易掌握容易产生交联所致。在溶解性能方面还表明3位异构体聚酰亚胺普遍处于4位异构体，由双酚A参与共聚的聚酰亚胺其溶解性能却不同程度地得到改善。热性能研究表明4位异构体聚酰亚胺较3位异构体聚酰亚胺稍稳定，由二酐与二胺缩聚和通过某核取代缩聚所得的相同结构的聚亚胺经DTA和DSC测试，其热稳定性基本相同。

A general theory on media with randomly distributed inclusions .1. The average field behaviors

In this paper, a theory is developed to calculate the average strain field in the materials with randomly distributed inclusions. Many previous researches investigating the average field behaviors were based upon Mori and Tanaka's idea. Since they were restricted to studying those materials with uniform distributions of inclusions they did not need detailed statistical information of random microstructures, and could use the volume average to replace the ensemble average. To study more general materials with randomly distributed inclusions, the number density function is introduced in formulating the average field equation in this research. Both uniform and nonuniform distributions of inclusions are taken into account in detail.

Phase control of higher spectral components in the presence of a static electric field

We investigate the higher spectral component generations driven by a few-cycle laser pulse in a dense medium when a static electric field is present. Our results show that, when assisted by a static electric field, the dependence of the transmitted laser spectrum on the carrier-envelope phase (CEP) is significantly increased. Continuum and distinct peaks can be achieved by controlling the CEP of the few-cycle ultrashort laser pulse. Such a strong variation is due to the fact that the presence of the static electric field modifies the waveform of the combined electric field, which further affects the spectral distribution of the generated higher spectral components.

强外加电场与大调制度下光折变动力学光栅形成研究

强外加电场与大调制度在光折变效应的研究中已经得到了广泛应用。采用PDECOL算法, 严格求解光折变带输运方程, 得到外加电场时不同调制度下光折变晶体中随时间变化的空间电荷场、载流子浓度, 并讨论了外加电场对它们的影响。通过将物质方程与耦合波方程联立数值求解, 可得到光折变光栅形成过程中两波耦合增益系数以及光束条纹相位的变化。模拟结果表明, 在强外加电场作用下, 两束记录光之间的光强与相位耦合都得到了增强, 而原有的解析式忽视了强外加电场与大调制度对空间电荷场相位耦合的影响, 此时不再适用。同时发现折射率光

Electric and magnetic losses and gains in determining the sign of refractive index

Within the framework of classic electromagnetic theories, we have studied the sign of refractive index of optical medias with the emphases on the roles of the electric and magnetic losses and gains. Starting from the Maxwell equations for an isotropic and homogeneous media, we have derived the general form of the complex refractive index and its relation with the complex electric permittivity and magnetic permeability, i.e. n = root epsilon mu, in which the intrinsic electric and magnetic losses and gains are included as the imaginary parts of the complex permittivity and permeability, respectively, as epsilon = epsilon(r) + i(epsilon i) and mu = mu(r) + i mu(i). The electric and magnetic losses are present in all passive materials, which correspond, respectively, to the positive imaginary permittivity and permeability epsilon(i) > 0 and mu(i) > 0. The electric and magnetic gains are present in materials where external pumping sources enable the light to be amplified instead of attenuated, which correspond, respectively, to the negative imaginary permittivity and permeability epsilon(i) < 0 and mu(i) < 0. We have analyzed and determined uniquely the sign of the refractive index, for all possible combinations of the four parameters epsilon(r), mu(r), epsilon(i), and mu(i), in light of the relativistic causality. A causal solution requires that the wave impedance be positive Re {Z} > 0. We illustrate the results for all cases in tables of the sign of refractive index. One of the most important messages from the sign tables is that, apart from the well-known case where simultaneously epsilon < 0 and mu < 0, there are other possibilities for the refractive index to be negative n < 0, for example, for epsilon(r) < 0, mu(r) > 0, epsilon(i) > 0, and mu(i) > 0, the refractive index is negative n < 0 provided mu(i)/epsilon(i) > mu(r)/vertical bar epsilon(r)vertical bar. (c) 2006 Elsevier B.V. All rights reserved.

基于Berreman矩阵的双折射薄膜光谱响应特性计算

采用Berreman特征矩阵方法，通过数值计算研究了双折射薄膜的反射、透射等光谱响应特性。依据电磁场理论的电场分量、磁场分量的界面连续条件，推导了光波在各向异性双轴薄膜中的Berreman转移矩阵，用以分析含有各向异性介质层的复杂薄膜系统的光学性质。这些矩阵递推关系包含了界面处的多点反射，适用于一般的各向异性的多层膜系统，包括入射媒质或基底为各向异性的情况。在文中给出了各向同性入射媒质双轴各向异性膜层一各向同性基底薄膜系统的计算结果，验证了该计算方法的可行性，以此作为进一步研究各向异性薄膜和相关光学薄膜器

A critical reassessment of the role of mitochondria in tumorigenesis

Background Mitochondrial DNA (mtDNA) is being analyzed by an increasing number of laboratories in order to investigate its potential role as an active marker of tumorigenesis in various types of cancer. Here we question the conclusions drawn in most of these investigations, especially those published in high-rank cancer research journals, under the evidence that a significant number of these medical mtDNA studies are based on obviously flawed sequencing results. Methods and Findings In our analyses, we take a phylogenetic approach and employ thorough database searches, which together have proven successful for detecting erroneous sequences in the fields of human population genetics and forensics. Apart from conceptual problems concerning the interpretation of mtDNA variation in tumorigenesis, in most cases, blocks of seemingly somatic mutations clearly point to contamination or sample mix-up and, therefore, have nothing to do with tumorigenesis. Conclusion The role of mitochondria in tumorigenesis remains unclarified. Our findings of laboratory errors in many contributions would represent only the tip of the iceberg since most published studies do not provide the raw sequence data for inspection, thus hindering a posteriori evaluation of the results. There is no precedent for such a concatenation of errors and misconceptions affecting a whole subfield of medical research.

Applications of factor-criteria system reconstruction analysis in the reproduction research on grass carp, black carp, silver carp and bighead in the Yangtze River

The natural reproduction of grass carp, black carp, silver carp, and bighead will be affected adversely by the Three Gorges Project in the Yangtze River. One of the methods to save the fish is to regulate the water levels, keeping them suited for the species to spawn. Nine factors associated with the scale of larvae-flood of the four species are classified into five levels, and the ranges of these factors producing larvae-floods are given by using the "factor-criteria system reconstruction analysis" method. Moderate beginning water levels and flow, with high daily increases in the rate of water level and flow, and a long duration of water level rising are important for the production of a large larvae-flood.

Electric Field Control of Interface Related Spin Splitting in Step Quantum Wells

Spin splitting of the AlyGa1-yAs/GaAs/AlxGa1-xAs/AlyGa1-yAs (x not equal y) step quantum wells (QWs) has been theoretically investigated with a model that includes both the interface and the external electric field contribution. The overall spin splitting is mainly determined by the interface contribution, which can be well manipulated by the external electric field. In the absence of the electric field, the Rashba effect exists due to the internal structure inversion asymmetry (SIA). The electric field can strengthen or suppress the internal SIA, resulting in an increase or decrease of the spin splitting. The step QW, which results in large spin splitting, has advantages in applications to spintronic devices compared with symmetrical and asymmetrical QWs. Due to the special structure design, the spin splitting does not change with the external electric field.

Integration of a photonic crystal polarization beam splitter and waveguide bend

In this work, we present the design of an integrated photonic-crystal polarization beam splitter (PC-PBS) and a low-loss photonic-crystal 60 waveguide bend. Firstly, the modal properties of the PC-PBS and the mechanism of the low-loss waveguide bend are investigated by the two-dimensional finite-difference time-domain (FDTD) method, and then the integration of the two devices is studied. It shows that, although the individual devices perform well separately, the performance of the integrated circuit is poor due to the multi-mode property of the PC-PBS. By introducing deformed airhole structures, a single-mode PC-PBS is proposed, which significantly enhance the performance of the circuit with the extinction ratios remaining above 20dB for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. Both the specific result and the general idea of integration design are promising in the photonic crystal integrated circuits in the future. (C) 2009 Optical Society of America

Electric field driven quantum phase transition between band insulator and topological insulator

We demonstrate theoretically that electric field can drive a quantum phase transition between band insulator to topological insulator in CdTe/HgCdTe/CdTe quantum wells. The numerical results suggest that the electric field could be used as a switch to turn on or off the topological insulator phase, and temperature can affect significantly the phase diagram for different gate voltage and compositions. Our theoretical results provide us an efficient way to manipulate the quantum phase of HgTe quantum wells.

Research on multi-degree-of-freedom neurons with weighted graphs

In this paper, we redefine the sample points set in the feature space from the point of view of weighted graph and propose a new covering model - Multi-Degree-of-Freedorn Neurons (MDFN). Base on this model, we describe a geometric learning algorithm with 3-degree-of-freedom neurons. It identifies the sample points secs topological character in the feature space, which is different from the traditional "separation" method. Experiment results demonstrates the general superiority of this algorithm over the traditional PCA+NN algorithm in terms of efficiency and accuracy.

Static and dynamic electric field domain formation in a doped GaAs/AlAs superlattice

We have observed the transition from static to dynamic electric field domain formation induced by a transverse magnetic field and the sample temperature in a doped GaAs/AlAs superlattice. The observations can be very well explained by a general analysis of instabilities and oscillations of the sequential tunnelling current in superlattices based solely on the magnitude of the negative differential resistance region in the tunnelling characteristic of a single barrier. Both increasing magnetic field and sample temperature change the negative differential resistance and cause the transition between static and dynamic electric field domain formation. (C) 2000 Elsevier Science B.V. All rights reserved.

Dynamic dc voltage band observed within each current branch in the transition from static to dynamic electric-field domain formation in a doped GaAs/AlAs superlattice

A dynamic dc voltage band was found emerging from each sawtooth-like branch of the current-voltage characteristics of a doped GaAs/AlAs superlattice in the transition process from static to dynamic electric-field domain formation caused by increasing the sample temperature. As the temperature increases, these dynamic dc voltage bands expand within each sawtooth-like branch, squeeze out the static regions, and join up together to turn the whole plateau into dynamic electric-field domain formation. These results are well explained by a general analysis of stability of the sequential tunneling current in superlattices. (C) 1999 American Institute of Physics. [S0003-6951(99)04443-5].