Mães obesas, filhotes obesos: estudo experimental

O aumento da obesidade materna pode refletir em efeitos deletérios na prole adulta, manifestos diferentemente de acordo com o gênero do indivíduo. Este trabalho teve como objetivo verificar a hipótese de que a obesidade materna provoca alterações metabólicas, na estrutura do tecido adiposo e hepático e mudanças de perfil inflamatório nas proles adultas de machos e fêmeas. Fêmeas C57BL/ 6 receberam dieta padrão (SC, 17% da energia proveniente do lipídeo) ou dieta hiperlipídica (HF; 49% da energia proveniente do lipídeo) durante oito semanas pré-gestacionais até a lactação. Após o desmame, os filhotes foram divididos nos grupos: SCM (machos), SCF (fêmeas), HFM (machos) e HFF (fêmeas). As características metabólicas foram avaliadas pela massa corporal (MC), glicemia de jejum, área sob a curva no teste oral de tolerância a glicose; concentrações de triglicerídes (TG) hepáticos e estimativa da esteatose hepática; análise plasmática de insulina, colesterol total (CT), triglicerídes (TG) e adipocinas; distribuição e análise morfológica do tecido adiposo e estado pró-inflamatório dos filhotes. Diferenças entre os grupos foram analisadas pelo Teste T não pareado (dados entre progenitoras e pares de grupos nas proles); one-way ANOVA com pós-teste de Tukey (para proles) e two-way ANOVA (efeito da dieta materna e gênero). O nível de significância adotado foi de P≤0,05. Progenitoras HF tiveram maior MC (+20%), glicemia elevada (+22%) e intolerância à glicose em comparação ao grupo SC. A partir da quarta semana, a MC mostrou-se maior nas proles HF, em ambos os gêneros, quando comparados às proles SC. Na 12 semana, a MC foi 20% maior no grupo HF macho e 30% maior no grupo HF fêmea do que seus controles (p<0,0001, ambos os gêneros). Intolerância à glicose foi observada em machos e fêmeas HF em relação aos seus contrapares SC (+20%, p<0,05). Proles HF demonstraram hepatomegalia com maior acúmulo de TG hepático, resultando em maior percentual de esteatose em machos (27%) e fêmeas HF (25%). Proles HF apresentaram incremento na adiposidade (+20%) e nos níveis de CT e TG do que seus congêneres SC. Níveis plasmáticos de leptina e insulina foram maiores, enquanto houve diminuição da adiponectina no grupo HF macho em relação ao grupo SC macho. Hipertrofia de adipócitos foi observada nas proles HF. TNF-alfa, IL-6 e leptina foram mais expressos em proles HF, porém diminuição na expressão de adiponectina foi evidenciada nas proles geradas por mães obesas. A luz do exposto, a dieta HF administrada em mães antes e durante períodos de gestação e lactação leva à obesidade materna que tem consequências na prole, tais como remodelamento do tecido adiposo, juntamente com alterações bioquímicas e metabólicas dos adipócitos, intensificando o estado pró-inflamatório da prole, em ambos os gêneros, na idade adulta.

小麦SKP1同源基因TSK1的克隆和功能分析

SKP1 (S-phase kinase-associated-protein 1) 家族蛋白是普遍存在于真核生物中的一类小分子量蛋白质，其主要的生物学功能在于参与SCF复合体的形成，从而调控生物体内泛素介导的蛋白质降解，并参与多方面的生物发育过程。SKP1蛋白能够同时和Cullin蛋白以及F-box蛋白结合，形成SCF复合体的核心部分。因此，SKP1正常功能的维持对于SCF复合体功能的实现至关重要。研究显示，植物中尤其是以拟南芥为代表模式植物中已经发现了21个SKP1基因成员，并发现其中的ASK1参与了多个SCF复合体的形成并调控着包括植物雄性减数分裂、生长素、赤霉素、茉莉酸和乙烯等生理和发育进程。但是来自高等植物尤其是小麦和水稻中的SKP1基因还鲜有报道，其功能还不为所知;此外，SKP1基因与ABA的关系还没有任何报道。 　　本文利用筛选小麦减数分裂期小花的cDNA文库结合RT-PCR的方法从小麦中分离到了一个SKP1同源基因，并命名为TSK1 (Triticum aestivum SKP1-Like 1)。序列比较结果显示TSK1与多个植物来源的SKP1基因有较高的同源性，对其推测的编码蛋白序列的分析发现TSK1与包括拟南芥来源的ASK1/ASK2等蛋白的羧基端存在非常高的保守性。 　　在对TSK1表达模式的研究中，本文发现TSK1主要是集中在小麦花序和幼根中表达。利用多种激素对小麦幼苗处理之后，发现TSK1的表达受ABA的抑制，但是当小麦中ABA合成受抑的情况下，TSK1的表达会有所增加，说明TSK1的表达受ABA的调控。RNA原位杂交显示TSK1基因在花顶端分生组织、花药以及幼根等分生较旺盛的组织中有较强的表达，暗示该基因可能参与了与细胞分裂相关的过程。 　　为了研究TSK1可能具有的功能，本文首先在ask1-1突变体背景上超表达TSK1，发现能够部分恢复ask1-1突变体雄性不育的表型，说明TSK1和ASK1在植物减数分裂过程中存在某种保守性。 　　在野生型拟南芥中超表达TSK1造成了拟南芥多个方面的变化，包括萌发和开花推迟，气孔开度减小等。进一步的观察发现，转基因植株的萌发和营养生长都呈现出对ABA的超敏感，后续证据证实这种ABA的超敏感性并不是由于转基因拟南芥中ABA合成途径的改变所造成的，而极有可能是影响了ABA的信号传导过程。RT-PCR的结果显示，转基因植株中多个ABA相关的已知基因表达量的发生了变化。 　　为了提供植物中SKP1家族成员参与调节植物ABA信号传导途径证据，本文对拟南芥ASK1/ask1 ASK12/ask2的杂合双突变体自交后代进行了研究。结果显示，ask1/ask1纯合突变体和ask1/ask1 ASK2/ask2植株表现出对ABA的弱敏感性。该结果从另一个侧面印证了TSK1超表达植株对ABA超敏感表型。 　　此外，TSK1超表达拟南芥也表现出生长素相关表型，也印证了该基因可能与ASK1类似，参与到生长素介导的根发育过程。 　　综上所述，本文认为TSK1参与了植物激素介导的植物发育过程，而且极有可能是形成了目前未知的某种SCF复合体。最重要的是，本文的结果为SCF复合体参与调节植物ABA信号传导途径提供了生理及遗传层面的证据。 　　 　　

抗对虾白斑综合症病毒单链抗体A1基因在酵母中表达及其与抗原结合活性

通过PCR从噬菌粒载体上扩增一种抗对虾白斑综合症病毒 (WSSV)的单链抗体A1(ScFvA1)基因 ,并构建于大肠杆菌 酵母穿梭质粒载体pPIC9K上。经PCR ,酶切 ,测序鉴定重组克隆 ,发现重组成功。将重组质粒pPIC9K ScF vA1转化毕赤酵母 (Pichiapastoris)GS115中 ,利用甲醇诱导 ,将单链抗体A1在酵母中进行了初步表达。经SDS PAGE电泳 ,发现其大小约为 32KD ,通过ELISA实验 ,证明表达上清液中的单链抗体具有很高的WSSV结合活性。

Depolarization blueshift in intersubband transitions of triangular quantum wires

Major State Basic Research Project 973 program of China 2006CB604907;National Science Foundation of China 60776015 60976008;863 High Technology R&D Program of China 2007AA03Z402

碳纤维增强聚芳醚酮材料的研究

用氧化法（KClO_3 + H_2SO_4）对吉林碳素厂生产的碳纤维短丝（SCF）进行了表面处理，并采用预混、热压等工艺制备了 SCF 增强聚芳醚酮（PEK－C）复合材料（SCF／PEK－C）。PEK－C 是应化所开发的新型树脂。用 SCF 增强后弯曲模量可高达 10GPa。弯曲强度达 170 MPa，接近短纤维增强 PEEK（英国帝国化学公司产品）水平，是一类很有前途的热塑性结构材料。本工作用光电子能谱（ESCA）等方法对碳纤维表面的氧化程度和表面性能进行了分析，用扫描电子显微镜（SEM）等研究了材料的断面形貌和界面粘结。并根据材料的弯曲模量，弯曲强度，剪切强度及动态力学性能等的测试结果，分析和讨论了碳纤维表面氧化程度 ～ 复合材料界面粘结 ～ 材料力学性能的关系。结果证明，碳纤维经氧化后，表面含氧基团增加，吸附活性提高，由此导致复合材料界面粘结的改善和力学性能的大幅度提高。用氧化后纤维增强 PEK－C 材料的断面不再出现园孔，只有少量的拔出纤维，基体出现皱褶。变曲模量和强度的增强因子分别提高了 60％ 和 210％。

猕猴胚胎干细胞自我更新机理及WNT 信号通路在猕猴胚胎早期发育中作用的研究

尽管大部分动物实验是在啮齿类动物上开展的，我们仍然相信涉及人类的许多问题，如胚胎干细胞的体内功能、调亡和肿瘤形成等只有在非人灵长类模型上才能得到最好的回答。猕猴(标准的非人灵长类动物模型)在解剖、生理和代谢方面都和人类非常相似。人类很多神经疾病，如阿尔茨海默氏病、帕金森病，只能在非人灵长类模型上才能精确建模。所以研究猕猴胚胎干细胞自我更新的原理及猕猴胚胎早期发育，对研究免疫排斥，检测基于胚胎干细胞的治疗的可行性，安全性和有效性具有重要意义。本文一方面对胚胎干细胞维持自我更新和多潜能性的机理研究进行了综述，另一方面对以下两个方面的内容进行了研究： 1）运用寡核苷酸芯片和定量PCR 验证的方法来分析五株猕猴饲养层细胞的表达模式，期望发现在支持性和非支持性的饲养层细胞中差异性表达的基因。我们着重定位于饲养层胞外空间和细胞膜上的细胞因子，因为这些因子可以通过直接接触或通过膜结合受体激活下游信号通路，并最终促进猕猴胚胎干细胞的自我更新。我们发现在支持性的饲养层中有八个基因是高表达的，他们是GREM2， bFGF，KITLG，DKK3，GREM1，AREG，SERPINF1 和LTBP1； 经定量PCR 验证的SCF，bFGF 和GREM2 的表达情况都和芯片数据吻合。 2）为了描述在IVF (in vitro fertilized, 体外受精)，ICSI (intracytoplasmic sperm injection, 单精注射)，SCNT (somatic cell nuclear transfer, 体细胞核移植)和孤雌生殖猕猴囊胚中WNT 信号通路的表达情况，我们运用了信号通路特异性PCR Array 系统及免疫细胞化学来检测mRNA 和蛋白表达水平。其中，ICSI 作为IVF 胚胎的参照组，以排除显微操作对胚胎质量的影响。结果，我们发现非经典WNT/JNK 信号，而不是经典WNT 信号通路，在IVF 正常胚胎发育中起作用。而体细胞核移植和孤雌生殖的胚胎的WNT 信号通路基因表达明显高于正常胚胎。WNT 信号通路基因的表达模式可以作为胚胎质量的一个指示标准，有助于回答为什么猕猴 SCNT 和孤雌生殖胚胎发育异常。

短炭纤维增强聚芳醚酮复合材料的研究

采用短炭纤维 (SCF)增强聚芳醚 (PEK- C)树脂 ,研究了不同的预混方法、纤维的表面处理、纤维的含量、成型温度和成型压力对复合材料性能的影响 ,优化了 SCF/ PEK- C复合材料的成型工艺

超临界溶液快速膨胀技术制备药物微细颗粒研究

本文主要研究了超临界溶液快速膨胀法（Rapid Expansi Qnofsu Percritical of Solution，RESs）制备微细颗粒装置的建立，并在此装置上考查了实现、布洛芬、黄体酮微细化处理的RESS过程工艺参数。RESS技术是超临界流体领域的一项新兴技术。其特点是借助于超．临界流体（Supercritial Fluids，SCF）的溶解性随其密度变化的关系，利用压力的改变，迅速地减小scF中溶质的溶解度，在极短的时间内在体系中造成极大的过饱和度和巨大扰动，形成微细而均一的溶质颗粒。在操作中可避免高温分解，还可有效避免副反应及有机物污染等问题。因此RESS法是一种安全、卫生的制备微细颗粒技术。我们根据RESS技术原理，查阅大量有关RESS过程的文献报道，利用原有超临界萃取装置的溶剂供应系统和萃取釜，又自行建立了包括预膨胀段、喷头、膨胀室、流量计以及附属于它们的控制、调节元件在内的膨胀收集单元：，构成了一套完整的RESS装置。许多药物的药效与其药物颗粒大小关系密切，随着颗粒尺寸的减小，它在体内的溶解和吸收速率提高。因此我们在本研究中选择两种药物-布洛芬、黄体酮进行微细化处理。布洛芬是一种重要的消炎镇痛药，我们首先在此装置上进行布洛芬的RESS过程研究，考察了操作条件对布洛芬微细颗粒粒径、比表面积、颗粒形态的影响。实验结果表明，利用此装置完全可以实现布洛芬的微细化处理。实验中还发现用多孔金属烧结板做喷嘴时，喷出产率特别大，这一特点为RESS法的工业化提供了重要可能性。黄体酮是一种重要的昌体类激素药物，它同时又是合成其它激素类药物的关键中间体。本研究也研究了黄体酮在此装置上实现RESS过程得到微细颗粒的可行性。研究结果表明：此装置同样适用于黄体酮的微细化处理。

An investigation of the roles of surface aluminum and acid sites in the zeolite MCM-22

Ammonia adsorption studies reveal that the observed Lewis acidity in the zeolite MCM-22 is derived from at least two types of framework aluminum sites (Al(F)), that is, octahedral Al(F) and three-coordinate Al(F). Comparative ammonia or trimethylphosphine (TMP) adsorption experiments with MCM-22 confirm that octahedral Al species gives rise to the signal at delta(ISO) approximate to 0 in the (27)Al NMR spectrum; this is a superposition of two NMR signals from the different Al species on the water-re constructed zeolite surface. A sharp resonance assigned to framework Al reversibly transforms on ammonia adsorption to delta(ISO) (27)Al approximate to 55 from tetrahedral Al(F), while the broad peak is assigned to nonframework aluminium which results from hydrothermal treatment. This study also demonstrates the effectiveness of (27)Al magic angle spinning (MAS) and multiple quantum (MQ) MAS NMR spectroscopy as a technique for the study of zeolite reactions.

In situ high temperature X-ray diffraction studies of mixed ionic and electronic conducting perovskite-type membranes

Phase structure and stability of three typical mixed ionic and electronic conducting perovskite-type membranes, SrCo0.8Fe0.2O3-delta (SCF), Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) and BaCo0.4Fe0.4Zr0.2O3-delta (BCFZ) were studied by in situ high temperature X-ray diffraction at temperatures from 303 to 1273 K and under different atmospheres (air, 2% O-2 in Ar and pure Ar) at 1173 K. By analyzing their lattice parameters the thermal expansion coefficients (TECs) of BSCF, SCF and BCZF are obtained to be 11.5 x 10(-6) K-1, 17.9 x 10(-6) K-1 and 10.3 x 10(-6) K-1, respectively. A relationship between phase stability and TEC was proposed: the higher is the TEC, the lower is the operation stability of the perovskite materials. (C) 2005 Elsevier B.V. All rights reserved.

Properties of molecules in tunnel junctions

Molecular tunnel junctions involve studying the behaviour of a single molecule sandwiched between metal leads. When a molecule makes contact with electrodes, it becomes open to the environment which can heavily influence its properties, such as electronegativity and electron transport. While the most common computational approaches remain to be single particle approximations, in this thesis it is shown that a more explicit treatment of electron interactions can be required. By studying an open atomic chain junction, it is found that including electron correlations corrects the strong lead-molecule interaction seen by the ΔSCF approximation, and has an impact on junction I − V properties. The need for an accurate description of electronegativity is highlighted by studying a correlated model of hexatriene-di-thiol with a systematically varied correlation parameter and comparing the results to various electronic structure treatments. The results indicating an overestimation of the band gap and underestimation of charge transfer in the Hartree-Fock regime is equivalent to not treating electron-electron correlations. While in the opposite limit, over-compensating for electron-electron interaction leads to underestimated band gap and too high an electron current as seen in DFT/LDA treatment. It is emphasised in this thesis that correcting electronegativity is equivalent to maximising the overlap of the approximate density matrix to the exact reduced density matrix found at the exact many-body solution. In this work, the complex absorbing potential (CAP) formalism which allows for the inclusion metal electrodes into explicit wavefunction many-body formalisms is further developed. The CAP methodology is applied to study the electron state lifetimes and shifts as the junction is made open.

Synthesis & characterisation of group IV semiconducting nanowires

Semiconductor nanowires, particularly group 14 semiconductor nanowires, have been the subject of intensive research in the recent past. They have been demonstrated to provide an effective, versatile route towards the continued miniaturisation and improvement of microelectronics. This thesis aims to highlight some novel ways of fabricating and controlling various aspects of the growth of Si and Ge nanowires. Chapter 1 highlights the primary technique used for the growth of nanowires in this study, namely, supercritical fluid (SCF) growth reactions. The advantages (and disadvantages) of this technique for the growth of Si and Ge nanowires are highlighted, citing numerous examples from the past ten years. The many variables involved in this technique are discussed along with the resultant characteristics of nanowires produced (diameter, doping, orientation etc.). Chapter 2 outlines the experimental methodologies used in this thesis. The analytical techniques used for the structural characterisation of nanowires produced are also described as well as the techniques used for the chemical analysis of various surface terminations. Chapter 3 describes the controlled self-seeded growth of highly crystalline Ge nanowires, in the absence of conventional metal seed catalysts, using a variety of oligosilylgermane precursors and mixtures of germane and silane compounds. A model is presented which describes the main stages of self-seeded Ge nanowire growth (nucleation, coalescence and Ostwald ripening) from the oligosilylgermane precursors and in conjunction with TEM analysis, a mechanism of growth is proposed. Chapter 4 introduces the metal assisted etching (MAE) of Si substrates to produce Si nanowires. A single step metal-assisted etch (MAE) process, utilising metal ion-containing HF solutions in the absence of an external oxidant, was developed to generate heterostructured Si nanowires with controllable porous (isotropically etched) and non-porous (anisotropically etched) segments. In Chapter 5 the bottom-up growth of Ge nanowires, similar to that described in Chapter 3, and the top down etching of Si, described in Chapter 4, are combined. The introduction of a MAE processing step in order to “sink” the Ag seeds into the growth substrate, prior to nanowire growth, is shown to dramatically decrease the mean nanowire diameters and to narrow the diameter distributions. Finally, in Chapter 6, the biotin – streptavidin interaction was explored for the purposes of developing a novel Si junctionless nanowire transistor (JNT) sensor.

Accelerating self-consistent field convergence with the augmented Roothaan-Hall energy function.

Based on Pulay's direct inversion iterative subspace (DIIS) approach, we present a method to accelerate self-consistent field (SCF) convergence. In this method, the quadratic augmented Roothaan-Hall (ARH) energy function, proposed recently by Høst and co-workers [J. Chem. Phys. 129, 124106 (2008)], is used as the object of minimization for obtaining the linear coefficients of Fock matrices within DIIS. This differs from the traditional DIIS of Pulay, which uses an object function derived from the commutator of the density and Fock matrices. Our results show that the present algorithm, abbreviated ADIIS, is more robust and efficient than the energy-DIIS (EDIIS) approach. In particular, several examples demonstrate that the combination of ADIIS and DIIS ("ADIIS+DIIS") is highly reliable and efficient in accelerating SCF convergence.

Paleoenvironmental reconstruction of the coastal Monte Léon and Santa Cruz formations (Early Miocene) at Rincón del Buque, Southern Patagonia: A revisited locality

© 2015 Elsevier Ltd.Sedimentological, ichnological and paleontological analyses of the Early Miocene uppermost Monte León Formation and the lower part of the Santa Cruz Formation were carried out in Rincón del Buque (RDB), a fossiliferous locality north of Río Coyle in Santa Cruz Province, Patagonia, Argentina. This locality is of special importance because it contains the basal contact between the Monte Léon (MLF) and the Santa Cruz (SCF) formations and because it preserves a rich fossil assemblage of marine invertebrates and marine trace fossils, and terrestrial vertebrates and plants, which has not been extensively studied. A ~90m-thick section of the MLF and the SCF that crops out at RDB was selected for this study. Eleven facies associations (FA) are described, which are, from base to top: subtidal-intertidal deposits with Crassotrea orbignyi and bioturbation of the Skolithos-Cruziana ichnofacies (FA1); tidal creek deposits with terrestrial fossil mammals and Ophiomorpha isp. burrows (FA2); tidal flat deposits with Glossifungites ichnofacies (FA3); deposits of tidal channels (FA4) and tidal sand flats (FA5) both with and impoverish Skolithos ichnofacies associated; marsh deposits (FA6); tidal point bar deposits recording a depauperate mixture of both the Skolithos and Cruziana ichnofacies (FA7); fluvial channel deposits (FA8); fluvial point bar deposits (FA9); floodplain deposits (FA10); and pyroclastic and volcaniclastic deposits of the floodplain where terrestrial fossil mammal remains occur (FA11).The transition of the MLF-SCF at RDB reflects a changing depositional environment from the outer part of an estuary (FA1) through the central (FA2-6) to inner part of a tide-dominated estuary (FA7). Finally a fluvial system occurs with single channels of relatively low energy and low sinuosity enclosed by a broad, low-energy floodplain dominated by partially edaphized ash-fall, sheet-flood, and overbank deposits (FA8-11). Pyroclastic and volcaniclastic materials throughout the succession must have been deposited as ash-fall distal facies in a fluvial setting and also were carried by fluvial streams and redeposited in both estuarine and fluvial settings. These materials preserve most of the analyzed terrestrial fossil mammals that characterize the Santacrucian age of the RDB's succession. Episodic sedimentation under volcanic influence, high sedimentation rates and a relatively warm and seasonal climate are inferred for the MLF and SCF section.Lateral continuity of the marker horizons at RDB serve for correlation with other coastal localities such as the lower part of the coastal SCF south of Río Coyle (~17.6-17.4Ma) belonging to the Estancia La Costa Member of the SCF.

Vibrational spectroscopy and DFT calculations of the di-amino acid peptide L-aspartyl-L-glutamic acid in the zwitterionic state

Solid state IR and Raman as well as aqueous solution state Raman spectra are reported for the linear di-amino acid peptide L-aspartyl-L-glutamic acid (L-Asp-L-Glu); the solution state Raman spectrum has also been obtained for the N,O-deuterated derivative. SCF-DFT calculations at the B3-LYP/cc-pVDZ level established that the structure and vibrational spectra of L-Asp-L-Glu can be interpreted using a model of the peptide with ten hydrogen-bonded water molecules, in conjunction with the conductor-like polarizable continuum solvation method. The DFT calculations resulted in the computation of a stable zwitterionic structure, which displays trans-amide conformation. The vibrational spectra were computed at the optimised molecular geometry, enabling normal coordinate analysis, which yielded satisfactory agreement with the experimental IR and Raman data. Computed potential energy distributions of the normal modes provided detailed vibrational assignments.