Diffusion-induced spontaneous pattern formation on gelation surfaces

Although the pattern formation on polymer gels has been considered as a result of the mechanical instability due to the volume phase transition, we found a macroscopic surface pattern formation not caused by the mechanical instability. It develops on gelation surfaces, and we consider the reaction-diffusion dynamics mainly induces a surface instability during polymerization. Random and straight stripe patterns were observed, depending on gelation conditions. We found the scaling relation between the characteristic wavelength and the gelation time. This scaling is consistent with the reaction-diffusion dynamics and would be a first step to reveal the gelation pattern formation dynamics.Comment: 7 pages, 4 figure

El patio central y su espíritu de trascendencia Escuela de Fado en Lisboa

Architecture, as the other arts has not been absolved from the fragility of human memory and that fatal costume of forgetting the past. Nowadays the nucleus of the architectural knowledge has been disaggregated, suffering a fragmentation waiting for a conciliation, an agreement that recompose the elements of this dispersed knowledge. But in one way or another, has known how to transcend his knowledge through the concept of type, this disposition capable of multiple developments. The present work search the conductor thread between the past and the future of architecture, in order to fortify the formal and theoretical content. Following the path proposed by Carlos Martí in his essay “The variations of identity: Essay on the type in architecture” that wants to generate a romantic conscience inside the architecture practice. This thesis has as purpose the analysis of the formal principle of the central courtyard typology, his morphological scheme of centrality and his application on the practical field. The Project search the application of the central courtyard typology within two projects of public character in different scales. The small one, recognize the basic characteristics of this morphological scheme on the São Bartolomé’s pavilion in Évora- Portugal. Meanwhile in a bigger scale and complexity is develop the Fado Music School in Lisbon.La arquitectura como las otras artes no se ha visto absuelta de la fragilidad de la memoria humana y aquella fatal costumbre de olvidar el pasado. En la actualidad el núcleo del saber arquitectónico se ha disgregado, padeciendo una fragmentación, a espera de la conciliación, de un acuerdo que recomponga los elementos de este saber disperso. Pero de una manera u otra, ha sabido trascender su conocimiento a través del concepto de tipo, esta disposición de la forma capaz de múltiples desarrollos. El presente trabajo busca reencontrar el hilo conductor entre el pasado y el futuro de la arquitectura, para fortalecer su contenido formal y teórico. Siguiendo el camino propuesto por Carlos Martí en su ensayo “Las variaciones de la identidad: Ensayo sobre el tipo en la arquitectura” se busca generar esta conciencia romántica dentro de la práctica arquitectónica. Este trabajo de titulación tiene como objeto de análisis el principio formal de la tipología de patio central, su esquema morfológico de centralidad y su aplicación en el plano práctico. El proyecto busca la aplicación del esquema formal de patio central dentro de dos proyectos de carácter público a diferentes escalas. El pequeño y conceptual, reconoce las características básicas de este esquema morfológico que es el Pabellón de la Ermita de São Bartolomé en Évora- Portugal. Mientras que a una escala mayor y más complejo se desarrolla la Escuela de Fado en Lisboa

Inactivation and Unfolding of the Hyperthermophilic Inorganic Pyrophosphatase from Thermus thermophilus by Sodium Dodecyl Sulfate

Inorganic pyrophosphatase (PPase, EC 3.6.1.1) is an essential constitutive enzyme for energy metabolism and clearance of excess pyrophosphate. In this research, we investigated the sodium dodecyl sulfate (SDS)-induced inactivation and unfolding of PPase from Thermus thermophilus (T-PPase), a hyperthermophilic enzyme. The results indicated that like many other mesophilic enzymes, T-PPase could be fully inactivated at a low SDS concentration of 2 mM. Using an enzyme activity assay, SDS was shown to act as a mixed type reversible inhibitor, suggesting T-PPase contained specific SDS binding sites. At high SDS concentrations, T-PPase was denatured via a two-state process without the accumulation of any intermediate, as revealed by far-UV CD and intrinsic fluorescence. A comparison of the inactivation and unfolding data suggested that the inhibition might be caused by the specific binding of the SDS molecules to the enzyme, while the unfolding might be caused by the cooperative non-specific binding of SDS to T-PPase. The possible molecular mechanisms underlying the mixed type inhibition by SDS was proposed to be caused by the local conformational changes or altered charge distributions

Non-specific protein binding by adsorbents designed for the specific affinity chromatography of sialidase in crude bacterial extracts

A number of derivatives of Sepharose 4B gels were prepared containing tyramine, -Gly-Gly-Tyr and the tetrapeptide, Thr (But)-Phe-Pro-Tyr-. A specific inhibitor of sialidase, p-diazo-phenyl oxamic acid, was also coupled to these phenol-substituted Sepharose gels. The effectiveness of these gels to purify sialidase by "affinity" chromatography was examined.The sialidase from Vibrio cholerae was adsorbed by these gels and subsequently re-eluted by a change in pH and temperature. The adsorption and elution of enzyme was independent of the presence or absence of the "specific inhibitor" of the sialidase, phenyl oxamic acid. A mechanism for the adsorption and subsequent elution of the sialidase is proposed.It is important to re-evaluate the biological data obtained with sialidase prepared by the affinity column recommended by Cuatrecasas and Illiano, Biochem. Biophys. Res. Commun. 44, 178-184 (1971), since glycosidases from Clostridium perfringens other than sialidase are also adsorbed and eluted under the conditions specified.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22211/1/0000644.pd

Phytohemagglutinin purification: A general method involving affinity and gel chromatography

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33834/1/0000092.pd

Poly(ADP-ribosyl)ation associated changes in CTCF-chromatin binding and gene expression in breast cells

CTCF is an evolutionarily conserved and ubiquitously expressed architectural protein regulating a plethora of cellular functions via different molecular mechanisms. CTCF can undergo a number of post-translational modifications which change its properties and functions. One such modifications linked to cancer is poly(ADP-ribosyl)ation (PARylation). The highly PARylated CTCF form has an apparent molecular mass of 180 kDa (referred to as CTCF180), which can be distinguished from hypo- and non-PARylated CTCF with the apparent molecular mass of 130 kDa (referred to as CTCF130). The existing data accumulated so far have been mainly related to CTCF130. However, the properties of CTCF180 are not well understood despite its abundance in a number of primary tissues. In this study we performed ChIP-seq and RNA-seq analyses in human breast cells 226LDM, which display predominantly CTCF130 when proliferating, but CTCF180 upon cell cycle arrest. We observed that in the arrested cells the majority of sites lost CTCF, whereas fewer sites gained CTCF or remain bound (i.e. common sites). The classical CTCF binding motif was found in the lost and common, but not in the gained sites. The changes in CTCF occupancies in the lost and common sites were associated with increased chromatin densities and altered expression from the neighboring genes. Based on these results we propose a model integrating the CTCF130/180 transition with CTCF-DNA binding and gene expression changes. This study also issues an important cautionary note concerning the design and interpretation of any experiments using cells and tissues where CTCF180 may be present

An overview of technical considerations for Western blotting applications to physiological research

The applications of Western/immuno-blotting (WB) techniques have reached multiple layers of the scientific community and are now considered routine procedures in the field of physiology. This is none more so than in relation to skeletal muscle physiology (i.e. resolving the mechanisms underpinning adaptations to exercise). Indeed, the inclusion of WB data is now considered an essential aspect of many such physiological publications to provide mechanistic insight into regulatory processes. Despite this popularity, and due to the ubiquitous and relatively inexpensive availability of WB equipment, the quality of WB in publications and subsequent analysis and interpretation of the data can be variable, perhaps resulting in spurious conclusions. This may be due to poor laboratory technique and/or lack of comprehension of the critical steps involved in WB and what quality control procedures should be in place to ensure robust data generation. The present review aims to provide a detailed description and critique of WB procedures and technicalities, from sample collection through preparation, blotting and detection to analysis of the data collected. We aim to provide the reader with improved expertise to critically conduct, evaluate and troubleshoot the WB process, to produce reproducible and reliable blots

Partial characterization of dinoflagellate chromosomal proteins

Dinoflagellate chromosomal proteins were analyzed by acrylamide gel electrophoresis. The electrophoretic pattern of acid-insoluble chromosomal proteins from Gyrodinium cohnii in sodium dodecylsulfate gels is less heterogeneous than that of corn, and is characterized by a paucity of bands representing molecular weights below 43 000. Acrylamide gel electrophoresis of G. cohnii and Peridinium trochoideum acid-soluble chromosomal proteins in urea at pH 3.2 gives a banding pattern quite different than that of typical histones. Acid-soluble protein from chromatin prepared by the two different methods and from both organisms migrates as one predominant band with a mobility slightly less than that of Histone IV from corn. Its molecular weight, estimated by sodium dodecylsulfate gel electrophoresis, is about 16000. It is a basic protein (basic/acidic amino acids 1.3) but differs from most histones in that it contains both cysteine and aromatic amino acids and somewhat lower levels of basic amino acids (18 mole % compared with 22 to 30% for histones). In addition, the major acid-soluble component is present in chromatin from log-phase cells but absent in chromatin from stationary-phase cells. For these reasons, the major acid-soluble protein is probably not a histone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22353/1/0000799.pd