Papers by Gabriela Valencia
Ceramics in Modern Technologies
Phosphatic porcelain (PP), commonly known as bone china, constitutes approximately 50 wt% bone as... more Phosphatic porcelain (PP), commonly known as bone china, constitutes approximately 50 wt% bone ash, 25 wt% kaolin, and 25 wt% feldspar, and its primary characteristics are high translucency and a high impact resistance. However, the low plasticity of these ceramic raw materials makes its moulding difficult owing to the plastic deformation due to the throwing wheel. Plasticizers or plasticity-promoting additives, such as sodium bentonite and methyl hydroxyethyl cellulose, modify the rheological behavior to pseudoplastic with a yield stress. Ceramic raw materials with plasticizers were prepared and characterized using helium pycnometry density, X-ray fluorescence, X-ray diffraction, and particle size distribution. In addition, characterization analysis was performed in commercial porcelain P905 for comparison purposes. The squeeze flow technique (compression of a cylindrical sample between two parallel plates) was employed to assess and compare the rheological behavior of the PP compositions with and without additives with the behavior of the commercial material. Results show that the addition of 4 wt% bentonite in the PP introduced a plasticity similar to that of the commercial porcelain, easing the shaping process using a throwing wheel. Plasticity index (PI) from the Atterberg test is useful; however, it is not sufficiently detailed to predict conformation performance of the ceramic raw materials in the throwing wheel as per the rheological information provided by the squeeze flow test.
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Revista Argentina de microbiología
Purified Protein Derivatives (PPDs) are non-defined antigens prepared from mycobacteria cultures.... more Purified Protein Derivatives (PPDs) are non-defined antigens prepared from mycobacteria cultures. They are usually employed to evaluate the specific cellular immune response both in animals and humans. Bovine and avian PPDs are usually employed as antigens in mycobacterial infections such as tuberculosis and paratuberculosis. Nevertheless, PPD from Mycobacterium avium subsp. paratuberculosis, (PPDj) is neither commonly used nor frequently available. However, PPD from Mycobacterium avium subsp. avium is in fact used. We aimed to obtain and evaluate the performance of a PPDj from a local isolate of MAP using the ãInterferon-release assay. The stimulation of ãInterferon-release was significantly different between infected and control cattle when this antigen, named PPDj-IB, was used. Stimulation in the infected animals was similar with both antigens (PPDa and PPDj-IB). However, some animals were positively stimulated with PPDj-IB and not with PPDa. We demonstrated by Western blot that ...
Biologicals, 2010
The lethality neutralization assay performed in mice is the standard recommended by the World Hea... more The lethality neutralization assay performed in mice is the standard recommended by the World Health Organization to estimate antivenom potency. The interpretation of its results without considering its analytical capacity may lead to erroneous conclusions. Therefore, laboratories that manufacture or control antivenoms must demonstrate the appropriateness of their models. A study of the method used at Instituto Clodomiro Picado, Costa Rica, to estimate the potency of antivenoms against Bothrops asper snake venom was performed. Results show that venom doses ranging from 2 to 6 Median Lethal Doses (LD 50) are appropriate to be used as challenge in this test. Variables such as the injection route, number of mice used per venom/antivenom level, and weight of the animals are critical in the estimation of the Median Effective Dose (ED 50), whereas incubation time is not. The assay has an acceptable selectivity, linearity, and limits of detection and quantification. Accuracy of the lethality neutralization assay, expressed as percentage recovery, was between 71% and 127%. Intermediate precision, expressed as relative standard deviation, was 17%. It is concluded that the analytical characteristics of this assay are adequate enough to prove product compliance and to have statistical control over an industrial line of antivenom serial production.
... Fuente: Conjunto Mínimo Básico de datos de Andalucía, Instituto Andaluz de Estadística. ... u... more ... Fuente: Conjunto Mínimo Básico de datos de Andalucía, Instituto Andaluz de Estadística. ... una mayor frecuencia de embarazo en el periodo 2000-2008 son Los Palacios y Villafranca, Osuna y Cabezas de San Juan. ... 6. Monterrosa A, Bello A. Atención obstétrica en adolescentes ...
Mycobacterium - Research and Development, Jun 20, 2018
Virulence, is referred as the ability of a pathogen to cause disease, and for mycobacteria it dep... more Virulence, is referred as the ability of a pathogen to cause disease, and for mycobacteria it depends on their ability to reside within host cells and evade the microbicidal mechanisms of macrophages. The outcome of tuberculosis (TB) infection is highly variable and it seems that the closest relationship between the Mycobacterium genre and humans has shaped the mycobacterial genome to encode bacterial factors that reflects a highly evolved and coordinated program of immune evasion strategies that interfere with both innate and adaptive immunity causing disease even in fully immunocompetent host. Although Mycobacterium tuberculosis (MTB) does not have classical virulence factors, it has described many virulence-associated genes and virulence lifestyle genes from Mycobacterium tuberculosis complex (MTBC). In this chapter, we describe the most important gene/molecule involved in the host defense modulation response, also the plethora of strategies to evade immune mechanisms of macrophage. We review the main genes whose inactivation in the mycobacterial genome leads to a measurable loss in virulence in the different validated TB models.
Journal of Molecular Neuroscience, 2012
The capacity of sympathoadrenal progenitors from adrenal medulla to generate dopaminergic neurons... more The capacity of sympathoadrenal progenitors from adrenal medulla to generate dopaminergic neurons in vitro makes them an attractive source for replacement therapies of neurodegenerative diseases such as Parkinson's disease. Dopaminergic cells constitute one percent of the adult adrenal medulla only. Thus, isolation of sympathoadrenal progenitors and enhancement of their capacity to derive dopaminergic neurons is a strategy to be considered. Here, we summarize data on the characterization and isolation of sympathoadrenal progenitors from adult adrenal medulla capable to give rise to functional dopaminergic neurons, in vitro. Pretransplantation treatment of these cells with pharmacological means is an important prerequisite to improve dopaminergic differentiation and efficient engraftment of sympathoadrenal progenitors. Treatment of these cells with retinoic and ascorbic acids significantly increased dopamine secretion from derived neurons. Furthermore, inhibition of Notch signaling activated molecular mechanisms involved in the determination of dopaminergic neuronal subtype. Taken together, somatic adrenomedullary sympathoadrenal progenitor cells are a valid cell source for replacement therapies with a high potential for dopaminergic neuronal differentiation.
Applied Cognitive Psychology
Working memory capacity plays a major role in many applied contexts, and it is important to be ab... more Working memory capacity plays a major role in many applied contexts, and it is important to be able to accurately measure this construct. The current studies tested whether the modality of administration of the letter-number sequencing task affects performance on the task. The letter-number sequencing task is a working memory capacity measure included as part of the Wechsler Adult Intelligence Scale-III and Wechsler Adult Intelligence Scale-IV test batteries. The task involves hearing a series of letters and digits, and then reporting back the stimuli with the letters in alphabetical order and digits in ascending numerical order. The task is traditionally administered orally, but recent studies have administered versions of the tasks visually by displaying stimuli on a computer screen. Results suggest that performance differences on the letter-number sequencing task may arise as a function of language background and task administration modality.
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Papers by Gabriela Valencia