Documente privitoare la familia Cantacuzino scoase n̋ cea ma¿ mare parte din archiva d-lu¿ G. Gr. Cantacuzino ¿i publicate.

Mode of access: Internet.

A.V. Kolʹt︠s︡ov kak poėt i chelovi︠e︡k; otzyvy V.G. Bi︠e︡linskago i Val. Maĭkova, pisʹma, "Zapisnai︠a︡ knizhka" i "Sobranīe poslovit︠s︡" Kolʹt︠s︡ova. S predisl. i primi︠e︡chanīi︠a︡mi sostaviteli︠a︡.

Mode of access: Internet.

Dynamis tēs alētheias : alēthinon diēgēma, ponēthen men Anglisti /

Layton, Evro. Greek Press at Malta of the ABCFM (1822-1833)

Ocular surface changes with short-term contact lens wear

Contact lenses are a common method for the correction of refractive errors of the eye. While there have been significant advancements in contact lens designs and materials over the past few decades, the lenses still represent a foreign object in the ocular environment and may lead to physiological as well as mechanical effects on the eye. When contact lenses are placed in the eye, the ocular anatomical structures behind and in front of the lenses are directly affected. This thesis presents a series of experiments that investigate the mechanical and physiological effects of the short-term use of contact lenses on anterior and posterior corneal topography, corneal thickness, the eyelids, tarsal conjunctiva and tear film surface quality. The experimental paradigm used in these studies was a repeated measures, cross-over study design where subjects wore various types of contact lenses on different days and the lenses were varied in one or more key parameters (e.g. material or design). Both, old and newer lens materials were investigated, soft and rigid lenses were used, high and low oxygen permeability materials were tested, toric and spherical lens designs were examined, high and low powers and small and large diameter lenses were used in the studies. To establish the natural variability in the ocular measurements used in the studies, each experiment also contained at least one “baseline” day where an identical measurement protocol was followed, with no contact lenses worn. In this way, changes associated with contact lens wear were considered in relation to those changes that occurred naturally during the 8 hour period of the experiment. In the first study, the regional distribution and magnitude of change in corneal thickness and topography was investigated in the anterior and posterior cornea after short-term use of soft contact lenses in 12 young adults using the Pentacam. Four different types of contact lenses (Silicone hydrogel/ Spherical/–3D, Silicone Hydrogel/Spherical/–7D, Silicone Hydrogel/Toric/–3D and HEMA/Toric/–3D) of different materials, designs and powers were worn for 8 hours each, on 4 different days. The natural diurnal changes in corneal thickness and curvature were measured on two separate days before any contact lens wear. Significant diurnal changes in corneal thickness and curvature within the duration of the study were observed and these were taken into consideration for calculating the contact lens induced corneal changes. Corneal thickness changed significantly with lens wear and the greatest corneal swelling was seen with the hydrogel (HEMA) toric lens with a noticeable regional swelling of the cornea beneath the stabilization zones, the thickest regions of the lenses. The anterior corneal surface generally showed a slight flattening with lens wear. All contact lenses resulted in central posterior corneal steepening, which correlated with the relative degree of corneal swelling. The corneal swelling induced by the silicone hydrogel contact lenses was typically less than the natural diurnal thinning of the cornea over this same period (i.e. net thinning). This highlights why it is important to consider the natural diurnal variations in corneal thickness observed from morning to afternoon to accurately interpret contact lens induced corneal swelling. In the second experiment, the relative influence of lenses of different rigidity (polymethyl methacrylate – PMMA, rigid gas permeable – RGP and silicone hydrogel – SiHy) and diameters (9.5, 10.5 and 14.0) on corneal thickness, topography, refractive power and wavefront error were investigated. Four different types of contact lenses (PMMA/9.5, RGP/9.5, RGP/10.5, SiHy/14.0), were worn by 14 young healthy adults for a period of 8 hours on 4 different days. There was a clear association between fluorescein fitting pattern characteristics (i.e. regions of minimum clearance in the fluorescein pattern) and the resulting corneal shape changes. PMMA lenses resulted in significant corneal swelling (more in the centre than periphery) along with anterior corneal steepening and posterior flattening. RGP lenses, on the other hand, caused less corneal swelling (more in the periphery than centre) along with opposite effects on corneal curvature, anterior corneal flattening and posterior steepening. RGP lenses also resulted in a clinically and statistically significant decrease in corneal refractive power (ranging from 0.99 to 0.01 D), large enough to affect vision and require adjustment in the lens power. Wavefront analysis also showed a significant increase in higher order aberrations after PMMA lens wear, which may partly explain previous reports of "spectacle blur" following PMMA lens wear. We further explored corneal curvature, thickness and refractive changes with back surface toric and spherical RGP lenses in a group of 6 subjects with toric corneas. The lenses were worn for 8 hours and measurements were taken before and after lens wear, as in previous experiments. Both lens types caused anterior corneal flattening and a decrease in corneal refractive power but the changes were greater with the spherical lens. The spherical lens also caused a significant decrease in WTR astigmatism (WRT astigmatism defined as major axis within 30 degrees of horizontal). Both the lenses caused slight posterior corneal steepening and corneal swelling, with a greater effect in the periphery compared to the central cornea. Eyelid position, lid-wiper and tarsal conjunctival staining were also measured in Experiment 2 after short-term use of the rigid and SiHy contact lenses. Digital photos of the external eyes were captured for lid position analysis. The lid-wiper region of the marginal conjunctiva was stained using fluorescein and lissamine green dyes and digital photos were graded by an independent masked observer. A grading scale was developed in order to describe the tarsal conjunctival staining. A significant decrease in the palpebral aperture height (blepharoptosis) was found after wearing of PMMA/9.5 and RGP/10.5 lenses. All three rigid contact lenses caused a significant increase in lid-wiper and tarsal staining after 8 hours of lens wear. There was also a significant diurnal increase in tarsal staining, even without contact lens wear. These findings highlight the need for better contact lens edge design to minimise the interactions between the lid and contact lens edge during blinking and more lubricious contact lens surfaces to reduce ocular surface micro-trauma due to friction and for. Tear film surface quality (TFSQ) was measured using a high-speed videokeratoscopy technique in Experiment 2. TFSQ was worse with all the lenses compared to baseline (PMMA/9.5, RGP/9.5, RGP/10.5, and SiHy/14) in the afternoon (after 8 hours) during normal and suppressed blinking conditions. The reduction in TFSQ was similar with all the contact lenses used, irrespective of their material and diameter. An unusual pattern of change in TFSQ in suppressed blinking conditions was also found. The TFSQ with contact lens was found to decrease until a certain time after which it improved to a value even better than the bare eye. This is likely to be due to the tear film drying completely over the surface of the contact lenses. The findings of this study also show that there is still a scope for improvement in contact lens materials in terms of better wettability and hydrophilicity in order to improve TFSQ and patient comfort. These experiments showed that a variety of changes can occur in the anterior eye as a result of the short-term use of a range of commonly used contact lens types. The greatest corneal changes occurred with lenses manufactured from older HEMA and PMMA lens materials, whereas modern SiHy and rigid gas permeable materials caused more subtle changes in corneal shape and thickness. All lenses caused signs of micro-trauma to the eyelid wiper and palpebral conjunctiva, although rigid lenses appeared to cause more significant changes. Tear film surface quality was also significantly reduced with all types of contact lenses. These short-term changes in the anterior eye are potential markers for further long term changes and the relative differences between lens types that we have identified provide an indication of areas of contact lens design and manufacture that warrant further development.

Crystalline A-DNA: The X-Ray Analysis of the Fragment d(G-G-T-A-T-A-C-C)

An A-DNA type double helical conformation was observed in the single crystal X-ray structure of the octamer d(G-G-T-A-T-A-C-C), 1, and its 5-bromouracil-containing analogue, 2. The structure of the isomorphous crystals (space group P61) was solved by a search technique based on packing criteria and R-factor calculations, with use of only low order data. At the present stage of refinement the R factors are 31 % for 1 and 28 % for 2 at a resolution of 2.25 A (0.225 nm). The molecules interact through their minor grooves by hydrogen bonding and base to sugar van der Waals contacts. The stable A conformation observed in the crystal may have some structural relevance to promoter regions where the T-A-T-A sequence is frequently found.

Sequence-dependent conformation of an A-DNA double helix: The crystal structure of the octamer d(G-G-T-A-T-A-C-C)

The crystal structures of the synthetic self-complementary octamer d(G-G-T-A-T-A-C-C) and its 5-bromouracil-containing analogue have been refined to R values of 20% and 14% at resolutions of 1·8 and 2·25 Å, respectively. The molecules adopt an A-DNA type double-helical conformation, which is minimally affected by crystal forces. A detailed analysis of the structure shows a considerable influence of the nucleotide sequence on the base-pair stacking patterns. In particular, the electrostatic stacking interactions between adjacent guanine and thymine bases produce symmetric bending of the double helix and a major-groove widening. The sugar-phosphate backbone appears to be only slightly affected by the base sequence. The local variations in the base-pair orientation are brought about by correlated adjustments in the backbone torsion angles and the glycosidic orientation. Sequence-dependent conformational variations of the type observed here may contribute to the specificity of certain protein-DNA interactions.

FTT-MA: A Flexible Time-Triggered Middleware Architecture for Time Sensitive, Resource-Aware AmI Systems

There is an increasing number of Ambient Intelligence (AmI) systems that are time-sensitive and resource-aware. From healthcare to building and even home/office automation, it is now common to find systems combining interactive and sensing multimedia traffic with relatively simple sensors and actuators (door locks, presence detectors, RFIDs, HVAC, information panels, etc.). Many of these are today known as Cyber-Physical Systems (CPS). Quite frequently, these systems must be capable of (1) prioritizing different traffic flows (process data, alarms, non-critical data, etc.), (2) synchronizing actions in several distributed devices and, to certain degree, (3) easing resource management (e.g., detecting faulty nodes, managing battery levels, handling overloads, etc.). This work presents FTT-MA, a high-level middleware architecture aimed at easing the design, deployment and operation of such AmI systems. FTT-MA ensures that both functional and non-functional aspects of the applications are met even during reconfiguration stages. The paper also proposes a methodology, together with a design tool, to create this kind of systems. Finally, a sample case study is presented that illustrates the use of the middleware and the methodology proposed in the paper.

Estudio de la Calidad Experimentada (QoE) en el Servicio de Navegación Web: Contribución a la Validación de las Recomendaciones ITU-T P.1501 e ITU-T G.1031

Muchos de los servicios que hasta hace relativamente poco tiempo eran ofertados únicamente por los operadores de telecomunicaciones, han pasado en la actualidad a ser prestados por terceros gracias al modelo de servicios en la nube, impulsando el auge de este modelo frente al tradicional. Esto trae consigo un incremento en la complejidad en la implantación por parte del proveedor de políticas para la gestión de la QoS demandada por el cliente.En este nuevo escenario, el concepto de calidad de servicio ha venido evolucionando desde su definición clásica, entendida como el análisis objetivo de los indicadores intrínsecos de calidad que definen el rendimiento de un servicio, hacia una visión subjetiva centrada en el punto de vista del cliente respecto a dicho servicio. En este contexto, organismos de estandarización como la ITU, a través de sus grupos de trabajo, están fomentando el interesante planteamiento de abordar los servicios de telecomunicaciones ampliamente asentados y más que estudiados desde la vertiente clásica de la QoS, desde este nuevo prisma enfocado al cliente, en el que poder establecer una metodología de estudio de la QoE en dichos servicios. En particular, el trabajo presentado en este documento se asienta en la validación del draft de la recientemente aprobada recomendación ITU-T P.1501 (Metodología de test subjetiva para el servicio de navegación web), así como en la contribución a la recomendación G.1031 (Factores de QoE en el servicio de navegación web).

G蛋白在松类植物花粉管发育中的亚细胞定位及调控机制

G蛋白参与了哺乳动物内多种细胞信号途径，但其在植物花粉萌发和花粉管发育过程中的细胞学定位、生化特性及功能研究比较滞后，有关这方面的研究报道较少。在显花植物授粉受精过程中，具顶端极性生长特性的花粉管是雄性生殖单位的载体，也是研究细胞生长分子调控机理的理想体系。与被子植物相比，裸子植物具有生长周期长，花粉管生长缓慢、易分叉等特点，具有不同于被子植物花粉发育的独特发育模式。对于裸子植物花粉萌发和花粉管生长的调控机理，目前尚不十分清楚。本文以松类植物中比较有代表性的裸子植物青杆（Piceawillsonii）和白皮松(Pinus bungeana)花粉为试材，应用免疫分析和间接免疫荧光显微镜技术，结合药理学实验和FTIR手段，研究了异三聚体G蛋白和小G蛋白在花粉管细胞中的定位、生化特性及其在花粉管发育中的调控作用。结果如下： 应用Western Blotting技术和来自于抗哺乳动物中不同序列G蛋白O【亚基抗体，我们在白皮松花粉管中检测到一条分子量为40 kDa左右的蛋白。去污剂处理显示，该蛋白与质膜偶联。间接免疫荧光显微镜实验发现，在花粉管发育的整个时期，代表Ga蛋白的荧光均一的分布在整个质膜区域，尤其在尖端皮层区域荧光最亮，显示此处该蛋白浓度最高。无论是在正常发育的花粉管抑或是发生弯曲或扭曲生长的花粉管，均呈现同样的分布模式。随着花粉管发育，Ga蛋白表达量发生变化。在花粉管发育中期，Ga蛋白表达量比较高;随着花粉管离体培养时间的延长，Ga蛋白表达量下降。另外，在花粉刚刚萌发时，Ga蛋白表达量也比较低。 对白皮松花粉萌发进行的药理学实验显示，G蛋白调节剂 CTX和PTX对白皮松花粉管的影响呈现双阶段效应。当添加的药剂浓度小于400 ng mL-I时，无论CTX还是PTX均抑制了花粉萌发和花粉管生长，且花粉管容易破裂;而当二者浓度分别升至500 ng mL-I时，同对照相比，花粉管生长明显受到促进。这一结果不支持Ma等人在百合花粉中的研究结果。进一步应用FTIR技术分析发现，当用浓度为400 ng mL-I CTX或PTX处理花粉管时，花粉管细胞壁酚类物质增加，而纤维素、半纤维素、木聚糖等物质下降，这可能是导致此浓度处理下花粉管易破裂的原因。这些结果显示了G蛋白a亚基参与了白皮松花粉管生长，CTX和PTX可能通过下游对其敏感的功能蛋白而非Ga本身，影响着花粉管生长并调控着花粉管壁的建成。 利用来源于烟草的抗NtRacl抗体和拟南芥的抗ROPs抗体，应用WeternBlotting技术，我们在青杆花粉管中检测到分子量为23kDa的多肽。间接免疫荧光显微镜实验显示，在花粉萌发18和24小时后，Rac蛋白主要定位于花粉管尖端质膜区域，时而会延伸到顶端两侧区域，但从尖端到基部存在浓度梯度，这种分布模式多在花粉管发育的后期观察到。Rac蛋白在青杆花粉管不同发育时期的分布模式变化可能和花粉管的生长状态有关，在花粉管发育早期和中期，正是花粉管旺盛生长期，Rac蛋白的尖端定位保证了花粉管的极性生长。对Rac蛋白在花粉管的分布进行的连续切片扫描发现，Rac蛋白不但分布在质膜上，并与质膜偶联，而且在胞质中亦有分布。通过对一系列正常发育（即极性生长的花粉管）和畸形发育的花粉管进行观察发现，Rac蛋白主要分布在旺盛生长的花粉管尖端质膜或离顶端20 Vm处，在分叉的生长缓慢的分枝端分布较少。而在那些发生分叉生长的花粉管中，处于次要位置的基本停止生长的分枝端几乎没有Rac蛋白存在。在顶端发生膨大的花粉管中，Rac蛋白均匀分布在花粉管整个质膜上，丧失浓度梯度，失去极性生长。这些结果显示了Rac蛋白参与了青杆花粉管生长。 应用抗NtRacl抗体进行的间接免疫荧光显微镜定位实验，我们在正在生长的花粉管的管核中观察到明亮的荧光，显示了有Rac蛋白的存在。当精细胞在花粉粒中未移动到花粉管中时，几乎没有观察到荧光信号。随着花粉管发育，两个精细胞的位置发生变化，当其中一个较大的精细胞移动到花粉管中时，观察到明亮的荧光信号，这些结果显示了Rac蛋白可能参与了管核或精细胞在花粉管内的移动。

Multiple expansions of C-4 plant biomass in East Asia since 7 Ma coupled with strengthened monsoon circulation

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