Humberto Ochoa
@uacj.mx
Principal Investigator, Dept. of Electrical and Computer Engineering
Universidad Autónoma de Ciudad Juárez
RESEARCH, TEACHING, or OTHER INTERESTS
Signal Processing, Computer Engineering, Electrical and Electronic Engineering
Scopus Publications
Scopus Publications
María Cristina Guevara Neri, Osslan Osiris Vergara Villegas, Vianey Guadalupe Cruz Sánchez, Humberto de Jesús Ochoa Domínguez, Manuel Nandayapa, and Juan Humberto Sossa Azuela
Elsevier BV
Rúben Castruita Rodríguez, Carlos Mendoza Carlos, Osslan Osiris Vergara Villegas, Vianey Guadalupe Cruz Sánchez, and Humberto de Jesús Ochoa Domínguez
Elsevier BV
Leandro José Rodríguez Hernández, Humberto de Jesús Ochoa Domínguez, Osslan Osiris Vergara Villegas, Vianey Guadalupe Cruz Sánchez, Juan Humberto Sossa Azuela, and Javier Polanco González
Springer International Publishing
Felipe Arias del Campo, María Cristina Guevara Neri, Osslan Osiris Vergara Villegas, Vianey Guadalupe Cruz Sánchez, Humberto de Jesús Ochoa Domínguez, and Vicente García Jiménez
Elsevier BV
Felipe Arias Del Campo, Osslan Osiris Vergara Villegas, Vianey Guadalupe Cruz Sanchez, Humberto De Jesus Ochoa Dominguez, and Manuel Nandayapa
Institute of Electrical and Electronics Engineers (IEEE)
The color quality of an image shown on a liquid crystal display (LCD) can be measured with a spectroradiometer; however, this instrument is expensive, work under controlled illumination conditions with an artificial source of light, and measurements take a long time. A spectroradiometer returns measurements of wavelength or CIE color space. A low-cost and fast alternative consists of using a digital camera that outputs RGB measurements. Unfortunately, comparisons between measurements obtained with both instruments cannot be performed; hence, conversion equations must be used. The main problem is that equations do not consider the effects caused by the camera lens, sensor variations, and configurable parameters such as gain and the exposure time. This paper proposes the architecture of a radial basis function neural network (RBFNN) to measure the image color quality displayed by an LCD using a digital camera. The RGB values acquired with a camera are used as inputs to the RBFNN. The output predicted the luminance and chromaticity components in the CIExyY color space and included the corrections to the lens and camera parameters. First, the RBFNN topology is explained, including the calculation of the number of neurons in the hidden layer, and the definition of the dispersion centers and their associated spread. Next, the experiments related to RGB color space reconstruction and conversion from RGB to CIE are presented. The proposed approach was tested on a real automotive scenario. The results obtained were similar to those measured with the spectroradiometer with an accuracy of 93.3%. Moreover, the results remained within limits established by the six-sigma methodology.
Nellie Moshkovich, Humberto J. Ochoa, Binwu Tang, Howard H. Yang, Yuan Yang, Jing Huang, Maxwell P. Lee, and Lalage M. Wakefield
American Association for Cancer Research (AACR)
Abstract Peptidylarginine deiminases (PADI) catalyze posttranslational modification of many target proteins and have been suggested to play a role in carcinogenesis. Citrullination of histones by PADI4 was recently implicated in regulating embryonic stem and hematopoietic progenitor cells. Here, we investigated a possible role for PADI4 in regulating breast cancer stem cells. PADI4 activity limited the number of cancer stem cells (CSC) in multiple breast cancer models in vitro and in vivo. Mechanistically, PADI4 inhibition resulted in a widespread redistribution of histone H3, with increased accumulation around transcriptional start sites. Interestingly, epigenetic effects of PADI4 on the bulk tumor cell population did not explain the CSC phenotype. However, in sorted tumor cell populations, PADI4 downregulated expression of master transcription factors of stemness, NANOG and OCT4, specifically in the cancer stem cell compartment, by reducing the transcriptionally activating H3R17me2a histone mark at those loci; this effect was not seen in the non-stem cells. A gene signature reflecting tumor cell–autonomous PADI4 inhibition was associated with poor outcome in human breast cancer datasets, consistent with a tumor-suppressive role for PADI4 in estrogen receptor–positive tumors. These results contrast with known tumor-promoting effects of PADI4 on the tumor stroma and suggest that the balance between opposing tumor cell–autonomous and stromal effects may determine net outcome. Our findings reveal a novel role for PADI4 as a tumor suppressor in regulating breast cancer stem cells and provide insight into context-specific effects of PADI4 in epigenetic modulation. Significance: These findings demonstrate a novel activity of the citrullinating enzyme PADI4 in suppressing breast cancer stem cells through epigenetic repression of stemness master transcription factors NANOG and OCT4.
Yuan Yang, Howard H. Yang, Binwu Tang, Alex Man Lai Wu, Kathleen C. Flanders, Nellie Moshkovich, Douglas S. Weinberg, Michael A. Welsh, Jia Weng, Humberto J. Ochoa,et al.
American Association for Cancer Research (AACR)
Abstract Purpose: TGFβs are overexpressed in many advanced cancers and promote cancer progression through mechanisms that include suppression of immunosurveillance. Multiple strategies to antagonize the TGFβ pathway are in early-phase oncology trials. However, TGFβs also have tumor-suppressive activities early in tumorigenesis, and the extent to which these might be retained in advanced disease has not been fully explored. Experimental Design: A panel of 12 immunocompetent mouse allograft models of metastatic breast cancer was tested for the effect of neutralizing anti-TGFβ antibodies on lung metastatic burden. Extensive correlative biology analyses were performed to assess potential predictive biomarkers and probe underlying mechanisms. Results: Heterogeneous responses to anti-TGFβ treatment were observed, with 5 of 12 models (42%) showing suppression of metastasis, 4 of 12 (33%) showing no response, and 3 of 12 (25%) showing an undesirable stimulation (up to 9-fold) of metastasis. Inhibition of metastasis was immune-dependent, whereas stimulation of metastasis was immune-independent and targeted the tumor cell compartment, potentially affecting the cancer stem cell. Thus, the integrated outcome of TGFβ antagonism depends on a complex balance between enhancing effective antitumor immunity and disrupting persistent tumor-suppressive effects of TGFβ on the tumor cell. Applying transcriptomic signatures derived from treatment-naïve mouse primary tumors to human breast cancer datasets suggested that patients with breast cancer with high-grade, estrogen receptor–negative disease are most likely to benefit from anti-TGFβ therapy. Conclusions: Contrary to dogma, tumor-suppressive responses to TGFβ are retained in some advanced metastatic tumors. Safe deployment of TGFβ antagonists in the clinic will require good predictive biomarkers.
Wansiri Chaisirin, Preechaya Wongkrajang, Nattakarn Praphruetkit, Tanyaporn Nakornchai, Sattha Riyapan, Onlak Ruangsomboon, Sathima Laiwejpithaya, Kavisara Rattanathummawat, Rungrudee Pavichai, and Tipa Chakorn
Western Journal of Emergency Medicine
Introduction Shortening emergency department (ED) visit time can reduce ED crowding, morbidity and mortality, and improve patient satisfaction. Point-of-care testing (POCT) has the potential to decrease laboratory turnaround time, possibly leading to shorter time to decision-making and ED length of stay (LOS). We aimed to determine whether the implementation of POCT could reduce time to decision-making and ED LOS. Methods We conducted a randomized control trial at the Urgency Room of Siriraj Hospital in Bangkok, Thailand. Patients triaged as level 3 or 4 were randomized to either the POCT or central laboratory testing (CLT) group. Primary outcomes were time to decision-making and ED LOS, which we compared using Mann-Whitney-Wilcoxon test. Results We enrolled a total of 248 patients: 124 in the POCT and 124 in the CLT group. The median time from arrival to decision was significantly shorter in the POCT group (106.5 minutes (interquartile [IQR] 78.3–140) vs 204.5 minutes (IQR 165–244), p <0.001). The median ED LOS of the POCT group was also shorter (240 minutes (IQR 161.3–410) vs 395.5 minutes (IQR 278.5–641.3), p <0.001). Conclusion Using a point-of-care testing system could decrease time to decision-making and ED LOS, which could in turn reduce ED crowding.
Leandro Morera Delfin, Raul Pinto Elias, Humberto de Jesús Ochoa Domínguez, and Osslan Osiris Overgara Villegas
Springer Science and Business Media LLC
Vicente García, J. Salvador Sánchez, Luis Alberto Rodríguez-Picón, Luis Carlos Méndez-González, and Humberto de Jesús Ochoa-Domínguez
Springer Science and Business Media LLC
Vicente García, Ana I. Marqués, J. Salvador Sánchez, and Humberto J. Ochoa-Domínguez
Springer Science and Business Media LLC
Leandro Morera Delfin, Mx Raul Pinto Elias, and Humberto de Jesús Ochoa Domínguez
Society for Imaging Science & Technology
Leandro Morera Delfin, Raul Pinto Elias, Humberto de Jesus Ochoa Dominguez, and Osslan Osiris Vergara Villegas
Society for Imaging Science & Technology
Erick Toledo Gómez, Humberto de Jesús Ochoa Domínguez, Soledad Vianey Torres Argüelles, and Leandro José Rodríguez Hernández
Springer International Publishing
Gerardo Adrián Martínez Medrano, Humberto de Jesús Ochoa Domínguez, and Vicente García Jiménez
Springer International Publishing
Leandro Morera-Delfín, Raúl Pinto-Elías, and Humberto-de-Jesús Ochoa-Domínguez
Springer International Publishing
Philip R. Brauer, Jee Hun Kim, Humberto J. Ochoa, Elizabeth R. Stratton, Kathryn M. Black, William Rosencrans, Eliza Stacey, and Engda G. Hagos
Informa UK Limited
Abstract Kru¨ppel like factor 4 (KLF4) is a transcription factor that regulates genes related to differentiation and proliferation. KLF4 also plays a role in metastasis via epithelial to mesenchymal transition. Here, we investigate the function of Klf4 in migration and invasion using mouse embryonic fibroblasts and the RKO human colon cancer cell line. Compared to wild-type, cells lacking Klf4 exhibited increased migration-associated phenotypes. In addition, overexpression of Klf4 in Klf4−/− MEFs attenuated the presence of stress fibers to wild-type levels. An invasion assay suggested that lack of Klf4 resulted in increased invasive capacity. Finally, analysis of RhoA showed elevated RhoA activity in both RKO and MEF cells. Taken together, our results strongly support the novel role of KLF4 in a post-translational regulatory mechanism where KLF4 indirectly modulates the actin cytoskeleton morphology via activity of RhoA in order to inhibit cellular migration and invasion.
Jose Manuel Mejia, Humberto Jesus Ochoa, Osslan Osiris Vergara, Boris Mederos, and vianey guadalupe cruz
Institute of Electrical and Electronics Engineers (IEEE)
In this paper we present an algorithm for the denoising of small animal positron emission images. The proposed algorithm combines a multiresolution transform with robust filtering of regions. The image is processed in the non-subsampled contourlet domain, taking advantage of the transform ability to capture geometric information of important structures like small lesions and borders between tissues. Additionally, in the transform domain, we proposed to apply quasi‑ robust potentials in order to reduce the noise on regions without borders, this is done by estimating an edge map and a set of image regions. Finally the inverse contourlet transform is applied to obtain a denoised image. Quality tests using the NEMA NU4 2008 phantom show that the proposed method reduces the noise in the image while at the same time the average count is preserved on each region. Comparisons with other methods, using a contrast analysis on a simulated lesion show the superiority of our approach to denoise and preserve small structures such as lesions.
V. García, J. S. Sánchez, L. Cleofas-Sánchez, H. J. Ochoa-Domínguez, and F. López-Orozco
Springer International Publishing
Humberto de Jesús Ochoa Domínguez and Vicente García Jiménez
Springer International Publishing
Humberto de Jesús Ochoa Domínguez, Leticia O. Máynez, Osslan O. Vergara Villegas, Boris Mederos, José M. Mejía, and Vianey G. Cruz Sánchez
Elsevier BV
Humberto de J. Ochoa Domínguez, Osslan O. Vergara Villegas, and Vianey G. Cruz Sanchez
SPIE-Intl Soc Optical Eng
Abstract. This paper introduces a modified set partitioning in hierarchical trees (SPIHT) algorithm that reduces the number of comparison operations and, consequently, the execution time needed to encode an image as compared to the SPIHT algorithm. The threshold of each independent subband is calculated after applying the discrete wavelet transform to the image. Scanning of the sets inside the subbands is determined by the magnitude of the thresholds that establishes a hierarchical scanning not only for the set of coefficients with larger magnitude, but also for the subbands. The algorithm uses the set partitioning technique to sort the transform coefficients. Results show that the modified SPIHT significantly reduces the number of operations and the execution time without sacrificing visual quality and the PSNR of the recovered image.
V. García, J. S. Sánchez, H. J. Ochoa Domínguez, and L. Cleofas-Sánchez
Springer International Publishing
Vicente Garcia, Humberto de Jesus Ochoa Dominguez, and Boris Mederos
Institute of Electrical and Electronics Engineers (IEEE)
Evaluation of medical image segmentation methods is an important task, frequently ignored in the medical image and computer vision community. Several scalar evaluation metrics have been proposed in the literature. Nevertheless, few efforts have been made to characterize the evaluation metrics. It is well-known that metrics measure different characteristics, in such way they might vary greatly among problem domains. Therefore, some of them will be more suitable in particular situations. In this paper, we analyze the behavior and ability of 17 discrepancy metrics to retain its value under a set of changes in a confusion matrix. We also perform an analysis of the consistency among peer metrics by using Pearson's correlation. Our aim is to provide a valuable insight to select the most suitable .discrepancy metric and show their advantages and weakness.