热致性液晶乙基纤维素和聚丙烯共混物的结构与性能

乙基纤维素(EC)和聚丙烯共混物沿取向方向有明显的絮条状结构,EC含量增加使T_c提高,△H和T_m有所降低,共混物的成核能力降低,结晶度下降,(110)晶面尺寸减小,(040)晶面尺寸增大。EC/PP共混物的η_a、τ_a真值更接近于PP结果。力学测定结果给出,EC/PP=10/90的共混物抗张模量有所增加,

喀斯特洞穴系统中稳定同位素地球化学特征及其环境意义

洞穴次生化学沉积物作为探索区域性、全球性气候变化规律和环境变迁史最重要的“信息库”之一，取得了不少有价值的研究成果。但同时，随着高分辨、短时间尺度气候-环境变化记录研究的开展与数据的进一步积累，也发现此类研究目前存在着一些问题与局限性。事实上，洞穴次生化学沉积物环境替代指标的形成经历了一系列复杂的过程，包含的影响因数相对较多。总的来说，其形成过程从大气降雨开始，穿越土壤层、洞穴盖板层到洞穴内滴水中CO2逸出、过饱和的CaCO3结晶和水中携带的不溶物沉淀。其中在不同的气候与环境条件下水与各层（如土壤层、表层喀斯特和潜水带等）中媒介之间发生的物理化学过程决定了环境替代指标的真实涵义。但目前有关这些替代指标的形成过程及其影响因子、适用性等方面的研究工作相当薄弱，尽管包括本文作者所在课题组在内的一些学者已认识到这一工作的重要性，零星做了一点工作，但还无法形成系统的认识。 在我国西南部，缺少类似我国北方的巨厚黄土堆积，但岩溶发育，且连片分布，其面积居世界首位（东亚喀斯特片区的中心）。因此，在该地区气候环境变迁史研究中，环境记录“档案”——洞穴次生化学沉积物在该方面所起的作用具有与北方黄土一样的重要意义。该研究为利用洞穴次生化学沉积物的地球化学特征恢复古生态环境意义的研究奠定坚实的理论基础。基于此，我们选择我国西南喀斯特发育最为典型的贵州作为研究区域，通过对分布于境内不同地方100多个洞穴进行实地考察和综合评判之后，筛选出一个系列的4个喀斯特洞穴作为研究对象，分别选取一定数量采样点进行采样。在前人研究的基础上，更加深入系统地对该4个洞穴系统中的稳定同位素（碳和氧同位素）进行研究。 分别系统地采集了4个洞穴系统中的大气、植物、土壤、土壤空气、土壤水、基岩、泉水、洞穴滴水、洞穴空气、塘水、潭水和滴水对应的洞穴次生化学沉积物等，现场测试pH值、电导率（Cond.）和气温（T）等，室内分别测试了稳定同位素和其他相关指标（如各种离子浓度等），以期开展不同生态环境条件下正在形成的洞穴次生化学沉积物及其对应的洞穴滴水的地球化学特征的比较研究，揭示它们对气候环境变化的响应机制，即稳定同位素等洞穴次生化学沉积物环境替代指标的现代形成过程以及各种影响因子。 本研究主要取得以下几点认识： 1. 虽然缺乏同气候、等海拔和生物量在10~90 t/hm2之间的植被序列洞穴的对比，以及对土壤有机质和土壤微生物活性等的相关试验研究，但根据分析仍可获知，洞穴化学次生沉积物的碳同位素的生物量效应是由植物碳同位素及土壤CO2微生物分馏作用机制共同制约。也就是说，洞穴沉积物碳同位素信号所反映的信息包括植被碳同位素组成及其生物量所控制的土壤性质（如微生物等），并不一定指示地表植被的C3/C4比例变化，甚至也不一定指示乔、灌、草的比例，当然也不仅仅是植被覆盖变化的简单体现。总之，生物量效应在横向上是存在的，它至少部分控制着洞穴化学次生沉积物碳同位素的变化，在对石笋等碳同位素的高分辨率解译过程中是不容忽视的。其机理可能是，生物量的大小控制土壤性质（营养和含水量等），进而激发或抑制土壤微生物群落的生长和发育，从而影响土壤有机质的分解过程最终导致次生沉积物δ13C值的变化。 2. 贵州喀斯特地区δ13CSOC与源植物的δ13C差值最大达8‰以上，其主要受土壤水热条件、质地和pH值控制。由此可见，δ13CSOC动态总体上反映了植被破坏历史。不过由于未进行具体年限测定，植被受破坏的具体时间未知。因此，今后除了需对SOC含量等问题进行系统的研究外，14C定年以及喀斯特地区更多土壤剖面等的工作也有待进一步开展。 3. 洞穴水在下渗过程中普遍发生了混合作用，致使从上（地表）到下（洞穴）δ13CDIC值变化幅度变小。除了QXD和JJD中δ13CDIC值偏重的滴水外，基岩对滴水碳同位素组成的影响都相对较小，而各洞穴中滴水（沉积物）等碳同位素组成与洞穴上覆植被等有关，是生态环境的真实记录。LFD中各种洞穴水δ13CDIC值之间基本上都达到或接近同位素平衡，且与洞穴系统的生态环境有很好的相关关系（非常显著的时间变化）；QXD和JJD之间的洞穴水（除土壤水外）δ13CDIC动态极为相似，即同一洞穴同期不同滴水点滴水δ13CDIC存在很大差异，可能与上覆土壤受到严重破坏导致基岩贡献率相对较高有关，而其中的几个滴水与相应沉积物的同位素不平衡可能是沉积速率太慢或沉积间断所致；XND尽管土壤水与JJD的有相似的特征，但其洞穴滴水平均δ13CDIC之间基本一致且与相应沉积物接近同位素平衡。因此，4个洞穴中，LFD可能是最为适合进行高分辨率和短时间尺度（如季节甚至月份）研究的洞穴。另外，对于文中出现的滴水（上）δ13CDIC偏重于滴水（下）的现象以及土壤中水气平衡的影响因素等还有待今后进一步研究。 4. 研究的4个洞穴系统大气降雨尽管主要受东亚季风控制，但来源不完全一致，还不同程度地受西南夏季风等影响。LFD和QXD受东亚季风影响程度相对高于XND和JJD，西南季风的影响程度恰好相反。 5. 尽管地表蒸发作用对表层（10cm以上）土壤水δ18O有一定的控制作用，但是较深（如10cm以下）土壤水基本不受影响；同位素示踪结果显示，土壤水和洞穴滴水对大气降水均有响应，但响应时间不一，可能与上覆物质（植被、土壤和基岩等）结构构造等控制的水文学特征和有效大气降水量等有关；喀斯特土壤的高度异质性导致土壤水运移机制的不同，从而影响混合作用的过程，最终导致洞穴系统同期土壤水δ18O存在一定差异；雨水在下渗过程中的不同来源水混合作用，是不同类型水δ18O时间上变化幅度不同的主要原因；同一洞穴不同滴水δ18O之间的差异可能与水文学特征不同有关；水化学性质（如SIC）控制沉积物的沉积过程从而影响同位素平衡。 由此可见，利用研究的4个洞穴系统中洞穴次生化学沉积物中氧同位素恢复和重建古降水量的高分辨率短时间变化是可行的。但我们也应注意到，在利用洞穴次生化学沉积物恢复和重建古降水量之前有必要寻找合适的方法（如利用Hendy法则等）判断是否达到同位素平衡。不是所有点沉积物都真实地记录着滴水（大气降水）同位素信号的，尤其在QXD和JJD中，一半左右的滴水点沉积物没有达到同位素平衡。这些均显示出在高分辨率短时间尺度古气候研究中，了解沉积物的形成过程对于准确解译洞穴过去环境变化具有重要意义。

Zinc polycarboxylate dental cement for the controlled release of an active organic substance: proof of concept

The potential of employing zinc polycarboxylate dental cement as a controlled release material has been studied. Benzalkonium chloride was used as the active ingredient, and incorporated at concentrations of 1, 2 and 3% by mass within the cement. At these levels, there was no observable effect on the speed of setting. Release was followed using an ion-selective electrode to determine changes in chloride ion concentration with time. This technique showed that the additive was released when the cured cement was placed in water, with release occurring by a diffusion mechanism for the first 3 h, but continuing beyond that for up to 1 week. Diffusion coefficients were in the range 5.62 × 10(−6) cm(2) s(−1) (for 1% concentration) to 10.90 × 10(−6) cm(2) s(−1) (for 3% concentration). Up to 3% of the total loading of benzalkonium chloride was released from the zinc polycarboxylate after a week, which is similar to that found in previous studies with glass-ionomer cement. It is concluded that zinc polycarboxylate cement is capable of acting as a useful material for the controlled release of active organic compounds.

Museums and youth: between misunderstanding and disappointment. Youth perceptions and arguments about the cultural consumption of museums in Chile

Young people are less explored in museum audience research; this is a paradoxical situation when considering its strategic location in the cultural reproduction and if considering the high performing cultural consumption compared with other sectors. The phenomenon of museums consumption by young Chileans who are self recognized as public and non-public museums is explored from a qualitative approach. It was conducted with focus groups in the three largest cities in Chile (Santiago, Valparaíso and Concepción). They identify the museum as a cultural institution in full force. However, in questioning museums activity youth reveal the specificity of their cultural matrix. This is referred to a social temporality based on the fragment, the discourse of familiarity, proximity and instead of breaking and critical. They claim a museum aesthetic / historical experience based on pleasure and enjoyment. An overview is proposed to further clarify the youth cultural consumption to characterize more precisely the place of the museum in the set, to design more effective policies museums.

Remediation of phenol-contaminated water by adsorption using poly(methyl methacrylate) (PMMA)

Recently polymeric adsorbents have been emerging as highly effective alternatives to activated carbons for pollutant removal from industrial effluents. Poly(methyl methacrylate) (PMMA), polymerized using the atom transfer radical polymerization (ATRP) technique has been investigated for its feasibility to remove phenol from aqueous solution. Adsorption equilibrium and kinetic investigations were undertaken to evaluate the effect of contact time, initial concentration (10-90 mg/L), and temperature (25-55 degrees C). Phenol uptake was found to increase with increase in initial concentration and agitation time. The adsorption kinetics were found to follow the pseudo-second-order kinetic model. The intra-particle diffusion analysis indicated that film diffusion may be the rate controlling step in the removal process. Experimental equilibrium data were fitted to five different isotherm models namely Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Redlich-Peterson by non-linear least square regression and their goodness-of-fit evaluated in terms of mean relative error (MRE) and standard error of estimate (SEE). The adsorption equilibrium data were best represented by Freundlich and Redlich-Peterson isotherms. Thermodynamic parameters such as Delta G degrees and Delta H degrees indicated that the sorption process is exothermic and spontaneous in nature and that higher ambient temperature results in more favourable adsorption. (C) 2011 Elsevier B.V. All rights reserved.

The technical merits of turbogenerating shown through the design, validation and implementation of a 1 dimensional engine model

Turbocompounding is the process of recovering a proportion of an engine’s fuel energy that would otherwise be lost in the exhaust process and adding it to the output power. This was first seen in the 1930s and is carried out by coupling an exhaust gas turbine to the crankshaft of a reciprocating engine. It has since been recognised that coupling the power turbine to an electrical generator instead of the crankshaft has the potential to reduce the fuel consumption further with the added flexibility of being able to decide how this recovered energy is used. The electricity generated can be used in automotive applications to assist the crankshaft using a flywheel motor generator or to power ancillaries that would otherwise have run off the crankshaft. In the case of stationary power plants, it can assist the electrical power output. Decoupling the power turbine from the crankshaft and coupling it to a generator allows the power electronics to control the turbine speed independently in order to optimise the specific fuel consumption for different engine operating conditions. This method of energy recapture is termed ‘turbogenerating’.

This paper gives a brief history of turbocompounding and its thermodynamic merits. It then moves on to give an account of the validation of a turbogenerated engine model. The model is then used to investigate what needs to be done to an engine when a turbogenerator is installed. The engine being modelled is used for stationary power generation and is fuelled by an induced biogas with a small portion of palm oil being injected into the cylinder to initiate combustion by compression ignition. From these investigations, optimum settings were found that result in a 10.90% improvement in overall efficiency. These savings relate to the same engine without a turbogenerator installed operating with fixed fuelling.

The crystal and molecular structure of bis (pyridoxamine) copper (II) dinitrate monohydrate

The crystal structure of Cu(PM)2(N03hoH20 (where PM is pyridoxamine, CSHI2N202) has been determined from three dimensional x-ray diffraction data. The crystals are triclinic, space group pI, a = 14.248 (2), b = 8.568 (1), c = 9.319 (1) 1, a = 94.08 (1), e = 89.73 (1), y~~ 99.18 (1)°, z = 2, jl(MoK) = 10.90 em-I, Po = 1.61 g/cm3 and Pc = 1.61 g/em3• The structure a was solved by Patterson techniques from data collected on a Picker 4-circle diffractometer to 26max = 45°. All atoms, including hydrogens, have been located. Anisotropic thermal parameters have been refined for all nonhydrogen atoms. For the 2390 independent reflections with F ? 3cr(F) , R = 0.0408. The results presented here provide the first detailed structural information of a metal complex with PM itself. The copper atoms are located on centres of symmetry and each is chela ted by two PM zwitterions through the amino groups and phenolate oxygen atoms. The zwitterionic form found in this structure involves the loss of a proton from the phenolate group and protonation of the pyridine ring nitrogen atoms. The two independent Cu(PM)2 moieties are symmetrically bridged by a single oxygen atom from one of the nitrate groups. The second nitrate group is not coordinated to the copper atoms but is central to an extensive hydrogen bonding network involving the water molecule and uncoordinated functional groups of PM.

Interactions between the cholinergic and dopaminergic systems during the production of ultrasonic vocalizations in rats

Rats produce ultrasonic vocalizations that can be categorized into two types of ultrasonic calls based on their sonographic structure. One group contains 22-kHz ultrasonic vocalization (USVs), characterized by relatively constant (flat) frequency with peak frequency ranging from 19 to 28-kHz, and a call duration ranging between 100 – 3000 ms. These vocalization can be induced by cholinomimetic agents injected into the ascending mesolimbic cholinergic system that terminates in the anterior hypothalamic-preoptic area (AH-MPO) and lateral septum (LS). The other group of USVs contains 50-kHz USVs, characterized by high peak frequency, ranging from 39 to 90-kHz, short duration ranging from 10-90 ms, and varying frequency and complex sonographic morphology. These vocalizations can be induced by dopaminergic agents injected into the nucleus accumbens, the target area for the mesolimbic dopaminergic system. 22-kHz USVs are emitted in situations that are highly aversive, such as proximity of a predator or anticipation of a foot shock, while 50 kHz USVs are emitted in rewarding and appetitive situations, such as juvenile play behaviour or anticipation of rewarding electrical brain stimulation. The activities of these two mesolimbic systems were postulated to be antagonistic to each other. The current thesis is focused on the interaction of these systems indexed by emission of relevant USVs. It was hypothesized that emission of 22 kHz USVs will be antagonized by prior activation of the dopaminergic system while emission of 50 kHz will be antagonized by prior activation of the cholinergic system. It was found that injection of apomorphine into the shell of the nucleus accumbens significantly decreased the number of carbachol-induced 22 kHz USVs from both AH-MPO and LS. Injection of carbachol into the LS significantly decreased the number of apomorphine-induced 50 kHz USVs from the shell of the nucleus accumbens. The results of the study supported the main hypotheses that the mesolimbic dopaminergic and cholinergic systems function in antagonism to each other.

Interactions between the cholinergic and dopaminergic system during the production of ultrasonic vocalizations in rats

Rats produce ultrasonic vocalizations that can be categorized into two types of ultrasonic calls based on their sonographic structure. One group contains 22-kHz ultrasonic vocalization (USVs), characterized by relatively constant (flat) frequency with peak frequency ranging from 19 to 28-kHz, and a call duration ranging between 100 – 3000 ms. These vocalization can be induced by cholinomimetic agents injected into the ascending mesolimbic cholinergic system that terminates in the anterior hypothalamic-preoptic area (AH-MPO) and lateral septum (LS). The other group of USVs contains 50-kHz USVs, characterized by high peak frequency, ranging from 39 to 90-kHz, short duration ranging from 10-90 ms, and varying frequency and complex sonographic morphology. These vocalizations can be induced by dopaminergic agents injected into the nucleus accumbens, the target area for the mesolimbic dopaminergic system. 22-kHz USVs are emitted in situations that are highly aversive, such as proximity of a predator or anticipation of a foot shock, while 50 kHz USVs are emitted in rewarding and appetitive situations, such as juvenile play behaviour or anticipation of rewarding electrical brain stimulation. The activities of these two mesolimbic systems were postulated to be antagonistic to each other. The current thesis is focused on the interaction of these systems indexed by emission of relevant USVs. It was hypothesized that emission of 22 kHz USVs will be antagonized by prior activation of the dopaminergic system while emission of 50 kHz will be antagonized by prior activation of the cholinergic system. It was found that injection of apomorphine into the shell of the nucleus accumbens significantly decreased the number of carbachol-induced 22 kHz USVs from both AH-MPO and LS. Injection of carbachol into the LS significantly decreased the number of apomorphine-induced 50 kHz USVs from the shell of the nucleus accumbens. The results of the study supported the main hypotheses that the mesolimbic dopaminergic and cholinergic systems function in antagonism to each other.

X-Ray Crysatllographic and Vibrational Spectroscopic Studies of Thorium Bromate Hydrate

Th(BrO3)3·H2O single crystals were grown from its aqueous solution at room temperature. Single crystal XRD, Raman and FTIR techniques were used to investigate the crystal structure. The crystal structure was solved by Patterson method. The as grown crystals are in monoclinic system with space group P21/c. The unit cell parameters are a = 12.8555(18) Å, b = 7.8970(11) Å, c = 9.0716(10) Å,  = 90°,  = 131.568° and  = 90° and unit cell volume is 689.1(2) Å3. Z = 8, R factor is 5.9. The Raman and FTIR studies indicate the lowering of symmetry of bromate anion from C3V to C1. Hydrogen bonds with varying strengths are present in the crystal. The centrosymmetric space group P21/c of the crystal is confirmed by the non-coincidence of majority of Raman and IR bands

Materiales de apoyo y adaptaciones curriculares para alumnos-as con necesidades educativas especiales.

Proyecto realizado en el Centro de Educación de Personas Adultas 'Rondilla', de Valladolid, por siete profesores, está orientado a alumnos con características especiales, debido a situaciones de desventaja social y fracaso escolar. Tiene como objetivo : Elaborar materiales de apoyo para motivar y dar respuesta a jóvenes con graves carencias socio-culturales con necesidades de preparación básica profesional, elemental para su incorporación al mercado de trabajo. La metodología seguida: 1) Parten de un trabajo de reflexión individual sobre los materiales de partida. 2) Se profundiza en seminarios. 3) Recogida y consulta bibliográfica. 4) Reelaboración de materiales. 5) Experimentación en aulas-taller. 6) Valoración de lo experimentado. 7) Nueva reelaboración. 8) Contraste con otras investigaciones análogas. 9) Conclusiones. Los materiales elaborados son : -Fichas de trabajo del educador. -Fichas de trabajo de los alumnos. Las fuentes de información utilizadas en el desarrollo del trabajo es la bibliografía e intercambio con otros colectivos. El trabajo no ha sido publicado.

Análisis de las competencias docentes del profesorado de la Universidad Politécnica de Valencia.

Definir operativamente y evaluar las competencias docentes del profesorado de la Universidad Politécnica de Valencia y formular propuestas de reciclaje para mejorar las disfunciones existentes y con ello la calidad de la enseñanza. 47 profesores de la Escuela Universitaria de Arquitectura Técnica y 29 profesores de Escuela Universitaria de Ingeniería Técnica Industrial de Valencia. 10,90 de la población docente de la Universidad Politécnica de Valencia. Ambas muestras constituyen el claustro completo de profesores de dichas Escuelas. Se elaboró un listado provisional de funciones del profesor y se envió a la Escuela para su revisión por profesores, alumnos y directivos. En función de esto se elaboró el cuestionario definitivo de competencias y los cuestionarios de observación de las mismas. Se llevó a cabo la observación de dos clases de cada profesor y una por medio de CCTV y se registraron los datos. Se cumplimentaron los cuestionarios de observación de profesores por parte de los alumnos, directores y los propios profesores. Recogida de opiniones de profesores, alumnos y directivos. Recogida y centralización de datos y elaboración de resultados y conclusiones. Cuestionario de observación de competencias y escala de observación CCTV. Observación. Estadística descriptiva. Tablas de frecuencias e histogramas. Los resultados obtenidos al pasar el cuestionario de competencias a profesores, alumnos y equipo investigador del ICE, reflejan una valoración altamente positiva del propio profesorado hacia las competencias que se cuestionan (y esto coincide en ambas escuelas). En cuanto al alumnado, las opiniones están repartidas y el índice de abstención es muy elevado. Las opiniones del equipo investigador oscila entre uno y otro bando. Se llegó a la elaboración de un perfil de 20 competencias específicas del profesor que sirvieron de base a todo el trabajo.

Predomina el estilo reflexivo en estudiantes de la Licenciatura en Derecho de la Universidad de Sonora, México.

Resumen basado en el de la publicación

Polymorphism, crystallinity and hydrophilic-lipophilic balance of stearic acid and stearic acid-capric/caprylic triglyceride matrices for production of stable nanoparticles

There is an increasing interest in lipid nanoparticles because of their suitability for several administration routes. Thus, it becomes even more relevant the physicochemical characterization of lipid materials with respect to their polymorphism, lipid miscibility and stability, as well as the assessment of the effect of surfactant on the type and structure of these nanoparticles. This work focuses on the physicochemical characterization of lipid matrices composed of pure stearic acid or of mixtures of stearic acid-capric/caprylic triglycerides, for drug delivery. The lipids were analyzed by Differential Scanning Calorimetry (DSC), Wide Angle X-ray Diffraction (WAXD), Polarized Light Microscopy (PLM) and hydrophilic-lipophilic balance (HLB) in combination with selected surfactants to determine the best solid-to-liquid ratio. Based on the results obtained by DSC and WAXD, the selected qualitative and quantitative composition contributed for the production of stable nanoparticles, since the melting and the tempering processes provided important information on the thermodynamic stability of solid lipid matrices. The best HLB value obtained for stearic acid-capric/caprylic triglycerides was 13.8, achieved after combining these lipids with accepted surfactants (trioleate sorbitan and polysorbate 80 in the ratio of 10:90). The proposed combinations were shown useful to obtain a stable emulsion to be used as intermediate form for the production of lipid nanoparticles. (C) 2011 Elsevier B.V. All rights reserved.

Transtornos de aprendizagem : aspectos neuropsicossociais de uma população encaminhada à Secretaria Municipal da Saúde da cidade de São Leopoldo

Foram estudados 125 pacientes em idade escolar que procuraram o Posto de Atendimento Médico Especializado (PAME) da cidade de São Leopoldo, Rio Grande do Sul, Brasil, nos anos de 2003 e 2004, encaminhados pela escola, pelo pediatra ou Conselho Tutelar, por estarem apresentando dificuldades na escolarização. Realizaram-se entrevistas com os pais ou responsáveis, exame neurológico tradicional, exame neurológico evolutivo, eletroencefalograma em sono e vigília em todas as crianças e tomografia cerebral e ressonância magnética, quando necessário. Foram estudados aspectos neuropsicossociais dos indivíduos e de suas respectivas famílias. Encontraram-se famílias comprometidas em sua história prévia e atual: 29,30% com dificuldades escolares, 27,20% com doenças psiquiátricas, 26,10% com epilepsia, 21,70% com alcoolismo e 10,90% com deficiência mental. As comorbidades tiveram um papel relevante no desempenho escolar: 50,50% com hiperatividade, 17,20% com distúrbio de conduta e 17,20% com problemas emocionais (listados como queixa principal por ocasião do encaminhamento para a triagem).