Papers by Linda Alexis Rivera
This chapter is part of a book that recounts the year's work at the Early Childhood Development C... more This chapter is part of a book that recounts the year's work at the Early Childhood Development Center (ECDC) at Texas A & M University-Corpus Christi. Rather than an "elitist" laboratory school for the children of university faculty, the dual-language ECDC is a collaboration between the Corpus Christi Independent School District and the university, with an enrollment representative of Corpus Christi's population. The chapter describes and evaluates The Literacy Connection, an ECDC program designed to improve parents' literacy skills so that their children's literacy skills, in turn, will improve. The program involves one-on-one tutoring for parents by university graduate assistants, with special emphasis on parents of 3-and 4year-olds. The project implementation involved several stages: (1) promoting awareness of the project within the university, the Corpus Christi Independent School District, and the educational community outside the university; (2) recruiting parents who wanted to increase their literacy and English language skills and develop basic computer skills; (3) soliciting support for materials and incentives from community representatives; (4) conducting the tutoring sessions; (5) presenting a parent workshop; (6) recognizing the success of the parents; and (7) evaluating the results. The evaluation found that learners were satisfied, and that the program had a high retention rate. (Contains 11 references.) (EV) Reproductions supplied by EDRS are the best that can be made from the original document.
International Journal of Optomechatronics, 2010
Long-term imaging of living biological specimens is important to infer behaviorial trends and cor... more Long-term imaging of living biological specimens is important to infer behaviorial trends and correlate neural structure with behavior. Such study is plagued by the field of view limitation in standard optical microscopes, as the motile specimen would frequently move out of view. A novel microscope, called the adaptive scanning optical microscope (ASOM), has recently been proposed to address this limitation.
Journal of Neuroimmune Pharmacology, 2010
Mononuclear phagocytes (monocytes, macrophages, and microglia) play an important role in innate i... more Mononuclear phagocytes (monocytes, macrophages, and microglia) play an important role in innate immunity against pathogens including HIV. These cells are also important viral reservoirs in the central nervous system and secrete inflammatory mediators and toxins that affect the tissue environment and function of surrounding cells. In the era of antiretroviral therapy, there are fewer of these inflammatory mediators. Proteomic approaches including surface enhancement laser desorption ionization, one-and two-dimensional difference in gel electrophoresis, and liquid chromatography tandem mass spectrometry have been used to uncover the proteins produced by in vitro HIV-infected monocytes, macrophages, and microglia. These approaches have advanced the understanding of novel mechanisms for HIV replication and neuronal damage. They have also been used in tissue macrophages that restrict HIV replication to understand the mechanisms of restriction for future therapies. In this review, we summarize the proteomic studies on HIV-infected mononuclear phagocytes and discuss other recent proteomic approaches that are starting to be applied to this field. As proteomic instruments and methods evolve to become more sensitive and quantitative, future studies are likely to identify more proteins that can be targeted for diagnosis or therapy and to uncover novel disease mechanisms.
Optomechatronic Technologies 2008, 2008
Traditional solutions for long term imaging of living small biological specimens and microorganis... more Traditional solutions for long term imaging of living small biological specimens and microorganisms lack efficiency due to computationally expensive algorithms, and field of view limitations in optical microscopes. This paper describes a new algorithm that allows for real time tracking of multiple 1mm nematodes called Caenorhabditis elegans with a novel optical microscope design called the Adaptive Scanning Optical Microscope (ASOM), developed at the Center for Automation Technologies and Systems (CATS). Based on the real time experimentation, an improved algorithm to track multiple worms in the presence of entanglements is generated. The stages of this development start with an enhanced digital motion controller for the ASOM high speed scanning mirror to suppress undesired vibrations that limit the system capacity to track multiple organisms. The second phase is the integration of the ASOM apparatus, the high speed motion control, and a base tracking algorithm, all which allows for rapid image acquisition to track multiple C. elegans in real time. The base algorithm was developed at CATS and has been proven to track a single C. elegans in real time. Results demonstrating the efficacy of the complete system are presented. Lastly, an enhanced tracking algorithm is described that shows improved accuracy and robustness in tracking worms even when they become entangled. Taking into account the unique ASOM design, individual segments of the worm are tracked throughout an image sequence, and a mosaic pattern covering the entire worm is subsequently created. The algorithm takes advantage of geometric and dynamic knowledge of the C. elegans such as size, and movement patterns. The enhanced algorithm is tested on previously recorded footage. Simulated tracking experiments also illustrate the effectiveness of the enhanced algorithm and are presented.
Current HIV Research, 2014
Mononuclear phagocytes including monocytes and macrophages, are important defense components of i... more Mononuclear phagocytes including monocytes and macrophages, are important defense components of innate immunity, but can be detrimental in HIV-1 infection by serving as the principal reservoirs of virus in brain and triggering a strong immune response. These viral reservoirs represent a challenge to HIV-1 eradication since they continue producing virus in tissue despite antiretroviral therapy. HIV-1 associated neurocognitive disorders (HAND) involve alterations to the blood-brain barrier and migration of activated HIV-1 infected monocytes to the brain with subsequent induced immune activation response. Our group recently showed that HIV replication in monocyte-derived macrophages is associated with increased cystatin B. This cysteine protease inhibitor also inhibits the interferon-induced antiviral response by decreasing levels of tyrosine phosphorylated STAT-1. These recent discoveries reveal novel mechanisms of HIV persistence that could be targeted by new therapeutic approaches to eliminate HIV in macrophage reservoirs. However, cystatin B has been also associated with neuroprotection. Cystatin B is an inhibitor of the cysteine protease cathepsin B, a potent neurotoxin. During HIV-1 infection cystatin B and cathepsin B are upregulated in macrophages. Reduction in cystatin/cathepsin interactions in infected macrophages leads to increased cathepsin B secretion and activity which contributes to neuronal apoptosis. Increased intracellular expression of both proteins was recently found in monocytes from Hispanic women with HAND. These findings provide new evidence for the role of cathepsin /cystatin system in the neuropathogenesis induced by HIV-infected macrophages. We summarize recent research on cystatin B and one of its substrates, cathepsin B, in HIV replication in macrophages and neuropathogenesis.
Journal of Applied Microbiology, 2015
This study aimed to select and validate different methodological strategies to quantify the expre... more This study aimed to select and validate different methodological strategies to quantify the expression of the virulence genes ascC and ascV by qPCR in Aeromonas salmonicida subsp. salmonicida (Aer. salmonicida). Using the geNorm, Normfinder and BestKeeper algorithms, reference genes for the qPCR were selected based on their in vitro expression stabilities in three Aer. salmonicida strains. Gene amplification efficiency was calculated by Real-time PCR Miner and LinReg PCR programmes, which have not been used previously in the analysis of bacterial gene expression. The expression of the ascC and ascV virulence genes in a virulent Aer. salmonicida strain was evaluated by three quantification models, including single (least or most stable) or three most stable reference genes, combined with constant or specific gene amplification efficiency. The most stable reference genes were gyrB, proC and rpoC, while rpoD and fabD were the least stable. Quantification models showed different expression patterns. The optimal strategy to quantify mRNA expression was to use a combination of the three algorithms and the quantification model including the three most stable reference genes. Real-time PCR Miner or LinReg PCR were valuable tools to estimate amplification efficiency. The methods used in this study gave more reliable expression data using qPCR than previously published methods. The quantification and expression dynamics of virulence genes will contribute to a better understanding of how Aer. salmonicida interacts with its host and the environment, and therefore to the prevention of epizootics due to this pathogen.
… Facultad Nacional de …, 2010
Resumen. Bajo condiciones de la sabana de Bogotá (Colombia), se evaluaron 32 cultivares de fríjol... more Resumen. Bajo condiciones de la sabana de Bogotá (Colombia), se evaluaron 32 cultivares de fríjol voluble por componentes del rendimiento y por su reacción a una mezcla de aislamientos de Colletotrichum lindemuthianum procedentes de Boyacá y Cundinamarca. ...
Medical Physics, 2010
Purpose: We use reduced-order constrained optimization (ROCO) to create clinically acceptable IMR... more Purpose: We use reduced-order constrained optimization (ROCO) to create clinically acceptable IMRT plans quickly and automatically for advanced lung cancer patients. Our new ROCO implementation works with the treatment planning system and full dose calculation used at Memorial Sloan-Kettering Cancer Center, and we have implemented mean dose hard-constraints, along with the point-dose and dose-volume constraints that we used for our previous work on the prostate. Methods: ROCO consists of three major steps. First, we sample the space of treatment plans by solving a series of optimization problems using penalty-based quadratic objective functions. Next, we find an efficient basis for this space via principal component analysis (PCA); this reduces the dimensionality of the problem. Finally, we solve a constrained optimization problem over this basis to find a clinically acceptable IMRT plan. Dimensionality reduction makes constrained optimization computationally efficient. Results: We apply ROCO to 12 stage III non-small-cell lung cancer (NSCLC) cases, generating IMRT plans that meet all clinical constraints and are clinically acceptable, and demonstrate that they are competitive with the clinical treatment plans. We also test how many samples and PCA modes are necessary to achieve an adequate lung plan, demonstrate the importance of long range dose calculation for ROCO, and evaluate the performance of non-specific normal tissue ("rind") constraints in ROCO treatment planning for the lung. Finally, we show that ROCO can save time for planners; we estimate that, in our clinic, planning using our approach would save a median of 105 minutes for the patients in our study. Conclusions: New challenges arise when applying ROCO to the lung site, which include the lack of a class solution, a larger treatment site, an increased number of parameters and beamlets, a variable number of beams and beam arrangement, and the customary use of rinds in clinical plans to avoid high-dose areas outside the PTV. In our previous work, use of an approximate dose calculation in the hard constraint optimization sometimes meant that clinical constraints were not met when evaluated with the full dose calculation. This difficulty has been removed in the current work by using the full dose calculation in the hard constraint optimization. We have demonstrated that ROCO offers a fast and automatic way to create IMRT plans for advanced NSCLC, which extends our previous application of ROCO to prostate cancer IMRT planning.
Journal of NeuroVirology, 2011
Cystatin B and signal transducer and activator of transcription-1 (STAT-1) phosphorylation have r... more Cystatin B and signal transducer and activator of transcription-1 (STAT-1) phosphorylation have recently been shown to increase human immunodeficiency virus-1 (HIV-1) replication in monocyte-derived macrophages (MDM), but the molecular pathways by which they do are unknown. We hypothesized that cystatin B inhibits the interferon (IFN) response and regulates STAT-1 phosphorylation by interacting with additional proteins. To test if cystatin B inhibits the IFN-β response, we performed luciferase reporter gene assays in Vero cells, which are IFN deficient. Interferon-stimulated response element (ISRE)-driven expression of firefly luciferase was significantly inhibited in Vero cells transfected with a cystatin B expression vector compared to cells transfected with an empty vector. To determine whether cystatin B interacts with other key players regulating STAT-1 phosphorylation and HIV-1 replication, cystatin B was immunoprecipitated from HIV-1-infected MDM. The protein complex was analyzed by liquid chromatography tandem mass spectrometry. Protein interactions with cystatin B were verified by Western blots and immunofluorescence with confocal imaging. Our findings confirmed that cystatin B interacts with pyruvate kinase M2 isoform, a protein previously associated cocaine enhancement of HIV-1 replication, and major vault protein (MVP), an IFN-responsive protein that interferes with JAK/STAT signals. Western blot studies confirmed the interaction with pyruvate kinase M2 isoform and MVP. Immunofluorescence studies of HIV-1-infected MDM showed that upregulated MVP colocalized with STAT-1. To our knowledge, the current study is the first to demonstrate the coexpression of cystatin B, STAT-1, MVP, and pyruvate kinase M2 isoform with HIV-1 replication in MDM and thus suggests novel targets for HIV-1 restriction in macrophages, the principal reservoirs for HIV-1 in the central nervous system.
Journal of Micro/Nanolithography, MEMS, and MOEMS, 2008
For a wide range of applications in biology, medicine, and manufacturing, the small field of view... more For a wide range of applications in biology, medicine, and manufacturing, the small field of view associated with high-resolution microscope systems poses a significant challenge in practice. To address this limitation, a novel optical microscope uses a micromachined MEMS deformable mirror working with a specially designed scan lens to achieve a two-order-of-magnitude increase in the field of view area. Called the adaptive scanning optical microscope ͑ASOM͒, the deformable mirror in the ASOM is an integral component of the optical system and the static ͑glass͒ optical elements are specifically designed to match the shape correcting capabilities of the deformable mirror itself. After describing the design and operating principle of the ASOM, experimental results from a low-cost prototype are presented. It is shown how an image-based optimization method can be used to first calibrate the electrical voltages to the MEMS deformable mirror. And once calibrated, we show how the deformable mirror can be used in an open loop control approach for very fast operation during run time. The methods for calibration of a MEMS deformable mirror and basic control structures demonstrated form the basis for a range of emerging adaptive-opticsenabled technologies and instrumentation.
International Journal of Radiation Oncology*Biology*Physics, 2011
Rev. Fac. Nal. Agr. …, 2010
evaluaron 32 cultivares de fríjol voluble por componentes del rendimiento y por su reacción a una... more evaluaron 32 cultivares de fríjol voluble por componentes del rendimiento y por su reacción a una mezcla de aislamientos de Colletotrichum lindemuthianum procedentes de Boyacá y Cundinamarca. Los genotipos que presentaron un buen comportamiento en rendimiento y una reacción en campo a la resistencia de la enfermedad fueron: D. Moreno y 3198. Los que expresaron una reacción de resistencia a la antracnosis fueron: 3180, 3182, 3177 y G-2333. Aquellos que mostraron un buen comportamiento en componentes de rendimiento fueron: 3164, 3159, 3176 y Radical. Estos genotipos podrían usarse como posibles candidatos parentales ó sobresalientes en el programa de mejoramiento de fríjol. También se realizó análisis de dos marcadores moleculares tipo SCAR ligados a los genes Co-4 y Co-5 que confieren resistencia a C. lindemuthianum, ninguno de los materiales de evaluación a excepción del testigo resistente G-2333, amplificó los marcadores SCAR, asociados a los genes de resistencia de interés.
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Papers by Linda Alexis Rivera