3,594 research outputs found
Andrés Bello "digital" [Recurso electrónico] : obras completas : bibliografía
No full textWindows 98, W98, WNT3.51 o superior; PC Pentium MMX 133 o superior; 64 Mb de RAM (recomendado 128 Mb), espaciolibre en disco duro local superior a 50 Mb; monitor SVGA, resolución 800 x 600, 64 colores; lector de DVD-Rom local o en redTítulo tomado de la etiquet
The Italian Words and Sentences MB-CDI: normative data and concordance between complete and short forms
No full textOne of the most popular and widely used parent report instruments for assessing early language acquisition is the MacArthur-Bates Communicative Development Inventories (MB-CDI). This study compares normative data of the Italian Words and Sentences complete form (WS-CF) and short form (WS-SF). The samples included 752 children for the WS-CF and 816 children for the WS-SF designed for children aged 18-36 months. The concordance between WS-SF and WS-CF is analyzed in a subgroup of 65 children. The results revealed strong correlations between WS-CF and WS-SF in both lexical and grammar skills as well as strong relationship between lexical and grammar skills. There was a high percentage agreement (97%) between the two forms for scores below the 10th percentile, suggesting that the two forms may be used interchangeably in order to describe vocabulary and grammatical development
Nouns and predicates comprehension and production in children with Down syndrome
No full textOur study investigated the lexical comprehension and production abilities as well as gestural production taking into account different lexical categories, namely nouns and predicates. Fourteen children with DS (34 months of developmental age) and a comparison group of 14 typically developing children (TD) matched for gender and developmental age were assessed through a test of lexical comprehension and production (PiNG) and the Italian MB-CDI. Children with DS showed a general weakness in lexical comprehension and production that appeared more evident when the lexicon was assessed through a structured test such as the PiNG that requires general cognitive skills that are impaired in children with DS. As for the composition of the lexical repertoire, for both groups of children, nouns are understood and produced in higher percentages compared to predicates. Children with DS produced more representational gestures than TD children in the comprehension tasks and above all with predicates; on the contrary, both groups of children exhibited the same number of gestures on the MB-CDI and during the subtests of PiNG production. Children with DS produced more unimodal gestural answers than the control group. Theoretical implications of these results are discussed. © 2014 Elsevier Ltd
Receiver Windowing Design for Narrowband Interference Mitigation in MB-OFDM UWB System
No full textIn 2005, the WiMedia Alliance working with the European Computer Manufacturers Association (ECMA) announced the establishment of the WiMedia MB-OFDM (Multiband Orthogonal Frequency Division Multiplexing) UWB radio platform as their global UWB standard. It was also chosen as the physical layer (PHY) of high data rate wireless specifications for high speed Wireless USB (W-USB), Bluetooth 3.0 and Wireless High-Definition Media Interface (HDMI). However, due to the low power and wide bandwidth nature of UWB systems, in-band narrowband interference (NBI) may hinder the receiver performance. This thesis presents an analysis of NBI impact on the MB-OFDM system for UWB communication. The intent of our analysis is to provide practical solutions for interference mitigation under different NBI models. In our work, a new receiver windowing for zero padding (ZP) OFDM system is proposed to reduce NBI spreading in the MB-OFDM UWB system. Simulations demonstrate the effectiveness of windowing under different NBI models.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
Presente y futuro de los marcadores cardiacos analizados en laboratorio clínico : artículo de revisión
No full textTesis (Tecnólogo Médico, especialidad en Bioanálisis Clínico, Inmunohematología y Banco de Sangre)Los antecedentes muestran que tras la incidencia cada vez mayor de las enfermedades
cardiovasculares en Chile, la aparición de marcadores biológicos de daño miocárdico,
especialmente troponinas (Tn), por su cardioespecificidad, y la creatinquinasa fracción MB
(CKMB), por su combinación de sensibilidad y precocidad diagnóstica, ha supuesto un notable
avance en el manejo de los pacientes con síndrome coronario agudo (SCA). El análisis seriado y el
uso combinado de ambos marcadores permite cubrir las necesidades diagnósticas, pronósticas y de
indicación terapéutica del síndrome coronario agudo. Sin embargo, a pesar sus indudables ventajas,
hay que enfatizar la importancia de conocer sus limitaciones e interpretar sus resultados teniendo
siempre en cuenta el contexto clínico de paciente, a su vez la inminente búsqueda de nuevos
marcadores cardiacos más precoces postulan al estrés oxidativo como el responsable del daño
celular posterior a un proceso de isquemia y repercusión.
Según esto, se define como el objetivo central de la investigación el entregar información
actualizada sobre los marcadores cardiacos clásicos y emergentes analizados en laboratorios
clínicos; lo que se cumple al realizar como metodología de investigación la revisión bibliográfica,
así como un exhaustivo sondeo con los encargados de realizar las técnicas analíticas de cada uno de
los marcadores utilizados como panel de estudio cardiaco en todos los hospitales del sector público
y privado de la V región. De acuerdo a lo anteriormente señalado, los resultados muestran que, el
100% de los centros hospitalarios (36 instituciones), utilizan como marcador cardiaco a CK total y
CKMB, de 21 hospitales públicos solo 8 ( 38,09%) miden troponina, 3 (14,28%)
lactatodeshidrogenasa (LDH) y 2 (9,52) mioglobina; dentro del sector privado de salud, con un total
de 15 instituciones, 11 de ellas (73,3%) determinan troponina y solo 1 (6,6%) mide PCR-us y BNP.
Si bien el marcador que denota mayor especificidad según los datos recopilados es la
troponina, existe una elevada heterogeneidad entre una técnica y otra, frente a las variaciones entre
sensibilidad y especificidad de los test comerciales disponibles se hace inminente la búsqueda de
la estandarización de estas técnicas para entregas resultados confiables al clínico con el fin de
reducir los tiempos y optimizar la utilización de recursos. El diagnóstico clínico de un paciente, no
se debe realizar con los resultados de un solo marcador de daño cardiaco, se deben tener un
conjunto de datos para el buen uso diagnóstico, como el electrocardiograma (ECG) y la anamnesis Los antecedentes muestran que tras la incidencia cada vez mayor de las enfermedades
cardiovasculares en Chile, la aparición de marcadores biológicos de daño miocárdico,
especialmente troponinas (Tn), por su cardioespecificidad, y la creatinquinasa fracción MB
(CKMB), por su combinación de sensibilidad y precocidad diagnóstica, ha supuesto un notable
avance en el manejo de los pacientes con síndrome coronario agudo (SCA). El análisis seriado y el
uso combinado de ambos marcadores permite cubrir las necesidades diagnósticas, pronósticas y de
indicación terapéutica del síndrome coronario agudo. Sin embargo, a pesar sus indudables ventajas,
hay que enfatizar la importancia de conocer sus limitaciones e interpretar sus resultados teniendo
siempre en cuenta el contexto clínico de paciente, a su vez la inminente búsqueda de nuevos
marcadores cardiacos más precoces postulan al estrés oxidativo como el responsable del daño
celular posterior a un proceso de isquemia y repercusión.
Según esto, se define como el objetivo central de la investigación el entregar información
actualizada sobre los marcadores cardiacos clásicos y emergentes analizados en laboratorios
clínicos; lo que se cumple al realizar como metodología de investigación la revisión bibliográfica,
así como un exhaustivo sondeo con los encargados de realizar las técnicas analíticas de cada uno de
los marcadores utilizados como panel de estudio cardiaco en todos los hospitales del sector público
y privado de la V región. De acuerdo a lo anteriormente señalado, los resultados muestran que, el
100% de los centros hospitalarios (36 instituciones), utilizan como marcador cardiaco a CK total y
CKMB, de 21 hospitales públicos solo 8 ( 38,09%) miden troponina, 3 (14,28%)
lactatodeshidrogenasa (LDH) y 2 (9,52) mioglobina; dentro del sector privado de salud, con un total
de 15 instituciones, 11 de ellas (73,3%) determinan troponina y solo 1 (6,6%) mide PCR-us y BNP.
Si bien el marcador que denota mayor especificidad según los datos recopilados es la
troponina, existe una elevada heterogeneidad entre una técnica y otra, frente a las variaciones entre
sensibilidad y especificidad de los test comerciales disponibles se hace inminente la búsqueda de
la estandarización de estas técnicas para entregas resultados confiables al clínico con el fin de
reducir los tiempos y optimizar la utilización de recursos. El diagnóstico clínico de un paciente, no
se debe realizar con los resultados de un solo marcador de daño cardiaco, se deben tener un
conjunto de datos para el buen uso diagnóstico, como el electrocardiograma (ECG) y la anamnesis clínica, lo que será de utilidad al médico quien iniciará prontamente el tratamiento a seguir de
acuerdo a los datos obtenidos. En relación al estrés oxidativo se ha visto que pacientes con infarto
agudo al miocardio presentan un aumento de la lipoperoxidación, cuantificada mediante la
medición de malondialdehido, lo que podría permitir en un futuro utilizarlo como indicador de
daño.The record shows that after increasing incidence of cardiovascular diseases in Chile, the
appearance of biomarkers of myocardial damage, especially troponin (Tn), for his cardio specificity
and creatine kinase MB fraction (CKMB), for its combination of sensitivity and early diagnosis has
been a marked advance in the management of patients with acute coronary syndrome (ACS).
Serious analysis and the combined use of both markers allows the needs of diagnostic, prognostic
and therapeutic indications of acute coronary syndrome. However, despite its undoubted
advantages, we must emphasize the importance of knowing their limitations and interpret their
results taking into account the clinical context of patient to turn the impending search for new
cardiac markers earlier postulate oxidative stress as responsible for cellular damage after ischemia,
a process and impact.
Accordingly, it is defined as the central objective of the investigation, the date information
on classic and emerging cardiac markers analyzed in clinical laboratories, which is met when
performing as the research methodology literature review and a comprehensive survey makers
analytical techniques to make each of the markers used as a panel study of heart hospitals in every
public and private sector of the V region. According to the above results show that 100% of
hospitals (36 institutions), used as a cardiac marker CK and CKMB total of 21 public hospitals,
only 8 (38.09%) measure troponin, 3 (14.28%) lactate dehydrogenase (LDH) and 2 (9.52)
myoglobin, in the private health sector, with a total of 15 institutions, 11 of them (73.3%) and only
determine troponin 1 (6, 6%) measured BNP and CRP-us.
While the score indicates greater specificity as the data is troponin, a high heterogeneity
between technique and compared to variations between sensitivity and specificity of commercially available test is imminent search for the standardization of these techniques supply reliable results
for the clinician to reduce the time and maximize resource utilization. The clinical diagnosis of a
patient should not be done with the results of a single marker of cardiac damage, it must have a data
set for the proper diagnostic use, such as electrocardiogram (ECG) and clinical history, which is
useful to the doctor who promptly begin to follow the treatment according to the data obtained. In
relation to oxidative stress has been seen that patients with acute myocardial infarction have an
increased lipoperoxidation, quantified by measuring malondialdehyde, which could allow a future
use as an indicator of damage
Altered immunolocalization of FGF23 in murine femora metastasized with human breast carcinoma MDA-MB-231 cells
No full textIntroduction After the onset of bone metastasis, tumor cells appear to modify surrounding microenvironments for their benefit, and particularly, the levels of circulating fibroblast growth factor (FGF) 23 in patients with tumors have been highlighted. Materials and methods We have attempted to verify if human breast carcinoma MDA-MB-231 cells metastasized in the long bone of nu/nu mice would synthesize FGF23. Serum concentrations of calcium, phosphate (Pi) and FGF23 were measured in control nu/nu mice, bone-metastasized mice, and mice with mammary gland injected with MDA-MB-231 cells mimicking primary mammary tumors. Results and conclusions MDA-MB-231 cells revealed intense FGF23 reactivity in metastasized lesions, whereas MDA-MB-231 cells cultured in vitro or when injected into the mammary glands (without bone metastasis) showed weak FGF23 immunoreactivity. Although the bone-metastasized MDA-MB-231 cells abundantly synthesized FGF23, osteocytes adjacent to the FGF23-immunopositive tumors, unlike intact osteocytes, showed no FGF23. Despite significantly elevated serum FGF23 levels in bone-metastasized mice, there was no significant decrease in the serum Pi concentration when compared with the intact mice and mice with a mass of MDA-MB-231 cells in mammary glands. The metastasized femora showed increased expression and FGFR1 immunoreactivity in fibroblastic stromal cells, whereas femora of control mice showed no obvious FGFR1 immunoreactivity. Taken together, it seems likely that MDA-MB-231 cells synthesize FGF23 when metastasized to a bone, and thus affect FGFR1-positive stromal cells in the metastasized tumor nest in a paracrine manner
ASIC FFT processor for MB-OFDM UWB system
No full textThe physical layer (PHY) standard of Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM) Ultra Wideband (UWB) system was defined by ECMA International. In this standard, the data sampling rate from the analog-to-digital converter to the physical layer is up to 528 Msample/s. Therefore, it is a challenge to realize the physical layer of the UWB system-especially the components with high computational complexity in Very Large Scale Integration (VLSI) implementation. Fast Fourier Transform (FFT) block is one of these components. FFT plays an important role in Multi-band OFDM UWB system, which is the demodulation block of OFDM signals. The purpose of this project is to design an Application Specific Integrated Circuit (ASIC) FFT solution for this system. The specification is defined from the system analysis and literature research. All the design choices and considerations are concluded and explained.Based on the algorithm and architecture analysis, a novel Radix22Parallel processor is proposed, which is a small-area and low-power-consumption solution for MB-OFDM UWB system. Both Field Programmable Gate Array (FPGA) and ASIC targeted synthesis results of this architecture are presented.Electrical Engineering, Mathematics and Computer Scienc
Sero-prevalence of hepatitis B surface antigen among pregnant women attending Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
No full textThe sero-prevalence of hepatitis B virus (HBV) infection study was conducted among pregnant women attending the Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State. Of the 120 serum samples screened, 10 (8.3%) were sero-positive. The
highest prevalence was recorded among the 30-34 years age-group (18.2%) followed by the 25-29 years age-group (9.1%) with the least in the 20-24 years age-group (6.3%). There were no significant differences between prevalence recorded and agegroups but these were significant associations between risk factors namely tribal marks/tattooing, types of marriages and prevalence of hepatitis infection. The prevalence of hepatitis B antigen among pregnant women suggests that vertical transmission of the virus has public health significance. It is therefore recommended that hepatitis B vaccination should be incorporated in the childhood immunization programme in Nigeria. Keywords: hepatitis B, sero-prevalence, pregnant women, Zaria. Nigeria.Nigerian Journal of Parasitology Vol. 29 (1) 2008 pp. 38-4
Characterization of the tertiary structure of the de novo designed protein MB-1
No full textMilk Bundle-1 (MB-1) is a de novo designed protein with 100 amino acids, having a molecular weight of 11.4 kilodaltons. MB-1 is enriched with 57% of selected essential amino acids (methionine, threonine, lysine and leucine), which are known to be limiting in dairy cattle. Recently, on the basis of a digestibility study, MB-1 was predicted to be unstable in rumen conditions.Characterization of the protein's structure was achieved using fluorescence spectroscopy (steady state measurements). MB-1 contains one tyrosine at position 62, expected to be in position "d" of helix III, in the hydrophobic core. Data obtained using fluorescence quenching indicates that the tyrosine is protected from the solvent in the putative hydrophobic core, as per design.Once it was established that MB-1 was not misfolded, further experiments were done to assess the fluidity of its hydrophobic core. For this, the amphiphillic dye ANSA was used. Results obtained for MB-1 compare favourably to those of many natural proteins, suggesting that MB-1 has achieved some degree of nativeness. Interestingly, MB-1 was found to exclude ANSA from its hydrophobic core more efficiently than all other de novo designed proteins reported to date.Finally, an analysis of folding thermodynamics of MB-1 was attempted. It was found that the fluorescence intensity of tyrosine was not sensitive to unfolding, making thermodynamic data impossible to obtain.Analysis of the data on MB-1 as compared to other natural proteins indicates that MB-1 is folded and compact. The lack of resistance to proteases must be caused by other factors other than the lack of compactness or misfolding. (Abstract shortened by UMI.).Source: Masters Abstracts International, Volume: 36-06, page: 1623.Adviser: Marc Beauregard
Exosomas secretadas por las células de cáncer de mama MDA-MB-231 post-interferencia de los RNAs mitocondriales no codificantes antisentido (ASncmtRNA) disminuyen las propiedades tumorogénicas
No full textTesis (Magíster en Biotecnología)El cáncer de mama es una de las enfermedades con mayor mortalidad en mujeres en el mundo donde las terapias de hoy en día, como la cirugía y radioterapia son insuficientes ya que no son efectivas en todos los pacientes, ocasionando una resistencia a éstos tratamientos lo que conlleva a una progresión del cáncer; principal razón que impulsa a buscar nuevas terapias para combatir ésta enfermedad. Nuestro grupo ha propuesto un nuevo blanco terapéutico, correspondiente a una familia de RNAs no codificantes de origen mitocondrial (ncmtRNAs) conformada por los transcritos sentido (SncmtRNA) y antisentido (ASncmtRNA). Al interferir los ASncmtRNAs con oligonucleótidos antisentido (ASOs), en líneas celulares normales y tumorales se observó una muerte celular masiva y selectiva sólo para células tumorales independiente de su origen y agresividad. El mecanismo por el cual ocurre esta muerte celular en células tumorales aún no ha sido elucidado completamente y es por esto que se quiso indagar en el rol que cumplirían los exosomas secretados posterior a la interferencia de los ASncmtRNAs. Los exosomas son vesículas extracelulares que pueden influir en el comportamiento de la célula receptora debido al contenido que éstos presentan, ya sean proteínas, lípidos o RNAs. Es por esto que primero se evaluó si las células de cáncer mama MDA-MB-231 eran capaces de secretar exosomas posterior a la interferencia de los ASncmtRNAs. Con resultados positivos, se purificó y caracterizó éstas vesículas por Western blot, Microscopia Electrónica de Transmisión (TEM) y un Análisis del Seguimiento de Nanopartículas (NTA). Una vez caracterizados los exosomas, éstos se utilizaron para evaluar ciertas propiedades tumorogénicas como invasión y la capacidad de crecer independiente de anclaje, tanto en comunicación autocrina como paracrina, y se observó una disminución en el potencial tumorogénico al estimular con exosomas aislados post-interferencia de los ASncmtRNAs. Los resultados de esta tesis sugieren que los exosomas derivados de la terapia disminuyen en las células tumorales propiedades tumorogénicas como: crecimiento independiente de anclaje, migración e invasión, tanto en comunicación autocrina como paracrina, efecto que podría ser atribuible al contenido exosomal.Breast Cancer is one of the most deadly diseases in women in the world. Current therapies, such as surgery and radiotherapy are not good enough treatments for this disease, since they are not effective in all patients, which causes resistance to these treatments leading to cancer progression, and it is for this reason that it is necessary to seek new therapies to target this disease. Our group has proposed a new therapeutic target, that corresponds to a family of non-coding mRNAs of mitochondrial origin (ncmtRNAs), conformed by sense (SncmtRNA) and antisense (ASncmtRNA) transcripts. The interference of ASncmtRNAs with antisense oligonucleotides (ASOs), in normal and tumor cell lines, generates massive and selective cell death just for tumor cells independent of their origin and agressiveness. The mechanism by which cell death occurs in tumor cells has not yet been elucidated completely and that is why we wanted to inquire into the role of secreted exosomes following the interference of the ASncmtRNAs. Exosomes are extracellular vesicles that can influence the behavior of the recipient cell due to the content they present, wether it be proteins, lipids or RNAs. This is why we first evaluated whether breast cancer cells MDA-MB-231 were able to secrete exosomes after ASncmtRNA interference. With positive results we purified and characterized these vesicles by Western blot, Transmission Electron Microscopy (TEM) and Nanoparticle Tracking Analysis (NTA). Once exosomes were characterized, they were used to evaluate certain tumorigenic properties such as invasion and anchorage independent capacity in paracrine and autocrine communication. A decrease in the tumorigenic potential was observed by stimulating recipient cells with exosomes isolated post-interference of the ASncmtRNAs. The results of this thesis suggests that exosomes derived from the therapy decrease tumorigenic properties in tumor cells such as, anchorage-independent growth, migration and invasion both in autocrine and paracrine communication. The effect could be attributable to exosomal content
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