Search

A method to identify and quantify amines in polymers by X-ray photoelectron spectroscopy using the energetic distribution of N1s atomic orbitals is presented in this work. The N orbital energetic states were obtained and associated with the atomic chemical states of amines through their formation energy. Pyrrole and allylamine plasma polymers were used as test polymers of this method because they potentially have primary, secondary and tertiary amines in their structure; although, additional unsaturated and oxidized amines were also found in the test polymers as a function of the synthesis power. The participation percentages of amines obtained with this method indicated that secondary amines had the greatest participation in the polymers followed by unsaturated and tertiary amines. The lowest participation belonged to primary amines or to the oxidized amines found during the analyses. This method is new and can be applied to other materials in solid state, not only to polymers, with enough stability to resist the X-ray beams of the XPS spectrometers. [ABSTRACT FROM AUTHOR]

The diet of the Clarendonian-early Hemphillian Pliohippus potosinus from the Paso del Águila local fauna, San Luis Potosí, central Mexico, was investigated using carbon and oxygen biogeochemical markers recovered from the dental enamel. Results indicate that P. potosinus was a mixed C3/C4 feeder with an important consumption of C4 plants, and that lived in a savanna. The lithic, structural and palynomorph records show the coexistence there of low lands and savanna plant taxa, quite probably the habitat of P. potosinus and of the camels present in this local fauna, with mountain slopes where forest taxa thrived, and constituted the habitat of cervids, also members of this fauna. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are the leading cause of death in the world, cell therapies have been shown to recover cardiac function in animal models. Biomaterials used as scaffolds can solve some of the problems that cell therapies currently have, plasma polymerized pyrrole (PPPy) is a biomaterial that has been shown to promote cell adhesion and survival. The present research aimed to study PPPy nanoparticles (PPPyN) interaction with adult rat ventricular cardiomyocytes (ARVC), to explore whether PPPyN could be employed as a nanoscaffold and develop cardiac microtissues. PPPyN with a mean diameter of 330 nm were obtained, the infrared spectrum showed that some pyrrole rings are fragmented and that some fragments of the ring can be dehydrogenated during plasma synthesis, it also showed the presence of amino groups in the structure of PPPyN. PPPyN had a significant impact on the ARVC´s shape, delaying dedifferentiation, necrosis, and apoptosis processes, moreover, the cardiomyocytes formed cell aggregates up to 1.12 mm2 with some aligned cardiomyocytes and generated fibers on its surface similar to cardiac extracellular matrix. PPPyN served as a scaffold for adult ARVC. Our results indicate that PPPyN-scaffold is a biomaterial that could have potential application in cardiac cell therapy (CCT). [ABSTRACT FROM AUTHOR]

Repetitive corrugation and straightening (RCS) is a method of severe plastic deformation that improves the mechanical properties in sheets of pure metals and alloys. In the present study, an A1100 alloy was processed by RCS, with a new die design. In order to determine the mechanical behavior and the texture evolution after the deformation process, sheets of A1100 alloy underwent 1, 3, and 6 RCS passes. X-ray diffraction analysis was employed to analyzing the crystallographic texture. Tensile and hardness tests were carried out to obtain the mechanical evolution of such properties. The results indicated that there was a noticeable increase (~55%) in the tensile strength after 6 RCS passes in comparison with the annealed samples. At difference of the reported with other die geometries, the stress-strain profile exhibited a large plastic plateau. As the appearance and intensity of a new texture, i.e. Goss texture (110) [001] increased, the intensity of cube texture decreased slightly, being associated to the RCS process. [ABSTRACT FROM AUTHOR]

Thermal-diffusivity ( D) and thermal-effusivity ( e) measurements were carried out in l-cysteine nanoliquids l-cysteine in combination with Au nanoparticles and protoporphyrin IX (PpIX) nanofluid) by using thermal lens spectrometry (TLS) and photopyroelectric (PPE) techniques. The TLS technique was used in the two mismatched mode experimental configuration to obtain the thermal-diffusivity of the samples. On the other hand, the sample thermal effusivity ( e) was obtained by using the PPE technique where the temperature variation of a sample, exposed to modulated radiation, is measured with a pyrolectric sensor. From the obtained thermal-diffusivity and thermal-effusivity values, the thermal conductivity and specific heat capacity of the sample were calculated. The obtained thermal parameters were compared with the thermal parameters of water. The results of this study could be applied to the detection of tumors by using the l-cysteine in combination with Au nanoparticles and PpIX nanofluid, called conjugated in this study. [ABSTRACT FROM AUTHOR]

Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme in regenerating nicotinamide adenine dinucleotide (NAD+) from nicotinamide in mammals. NAMPT has crucial roles for many cellular functions by regulating NAD+-dependent SIRT1 deacetylase. However, roles of NAMPT in cancer are poorly defined. In this study, we show that NAMPT is prominently overexpressed in human prostate cancer cells along with SIRT1. Elevation of NAMPT expression occurs early for the prostate neoplasia. Inhibition of NAMPT significantly suppresses cell growth in culture, soft agar colony formation, cell invasion and growth of xenografted prostate cancer cells in mice. NAMPT knockdown sensitizes prostate cancer cells to oxidative stress caused by H2O2 or chemotherapeutic treatment. Overexpression of NAMPT increases prostate cancer cell resistance to oxidative stress, which is partially blocked by SIRT1 knockdown. We demonstrate that in addition to modulating SIRT1 functions, the NAMPT inhibition reduces forkhead box, class 'O' (FOXO)3a protein expression and its downstream anti-oxidant genes catalase and manganese superoxide dismutase. Our results suggest important roles of concomitant upregulation of NAMPT and SIRT1 along with increased FOXO3a protein level for prostate carcinogenesis and their contribution to oxidative stress resistance of prostate cancer cells. These findings may have implications for exploring the NAMPT pathway for prostate cancer prevention and treatment. [ABSTRACT FROM AUTHOR]