Juan Manuel Toledo Santiago - Academia.edu (original) (raw)
Papers by Juan Manuel Toledo Santiago
Cuadernos De Economia, 2009
Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto
Memorie Della Societa Astronomica Italiana Supplementi, 2006
Protostars form in regions which are deeply hidden in molecular clouds and are surrounded by thic... more Protostars form in regions which are deeply hidden in molecular clouds and are surrounded by thick envelopes. Molecular outflows have the key to investigate the earliest evolutionary stages of star formation, especially at low luminosities where the outflow geometry can be relatively simple. In particular, the chemical changes induced by the passage of shocks associated with outflows can be used to try to establish an evolutionary scheme for outflows and consequently for the driving protostars. The main results obtained using mm-wavelength antennas during pilot projects focused on a small number of objects are shown. The strategy to carry on the project with the SRT is discussed.
Cierta clase de optimismo, o de supuesto optimismo, afirma que si nos esforzamos pensando, o si s... more Cierta clase de optimismo, o de supuesto optimismo, afirma que si nos esforzamos pensando, o si somos lo suficientemente racionales, podemos resolver todos nuestros problemas". H. A. Simon "En la medida en que se refieren a la realidad las proposiciones matemáticas no son ciertas, y en la medida en que son ciertas no se refieren a la realidad". Albert Einstein El siglo pasado dejó a su paso importantes desarrollos de la teoría económica, entre los que se destacan la teoría de la elección racional y el modelo 1 Juan Santiago es Magister en Educación y Magister(c) en Ingenieria financiera y estudiante del Doctorado en Ciencias Económicas. Se desempeña actualmente como profesor de probabilidad, inferencia y modelos de análisis estadísticos en la Facultad de
Microfluidics, BioMEMS, and Medical Microsystems XIII, 2015
Single cell analyses of RNA and DNA are crucial to understanding the heterogeneity of cell popula... more Single cell analyses of RNA and DNA are crucial to understanding the heterogeneity of cell populations. The numbers of approaches to single cells analyses are expanding, but sequence specific measurements of nucleic acids have been mostly limited to studies of either DNA or RNA, and not both. This remains a challenge as RNA and DNA have very similar physical and biochemical properties, and cross-contamination with each other can introduce false positive results. We present an electrokinetic technique which creates the opportunity to fractionate and deliver cytoplasmic RNA and genomic DNA to independent downstream analyses. Our technique uses an on-chip system that enables selective lysing of cytoplasmic membrane, extraction of RNA (away from genomic DNA and nucleus), focusing, absolute quantification of cytoplasmic RNA mass. The absolute RNA mass quantification is performed using fluorescence observation without enzymatic amplification in < 5 min. The cell nucleus is left intact and the relative genomic DNA amount in the nucleus can be measured. We demonstrate the technique using single mouse B lymphocyte cells, for which we extracted an average of 14.1 pg total cytoplasmic RNA per cell. We also demonstrate correlation analysis between the absolute amount of cytoplasmic RNA and relative amount of genomic DNA, showing heterogeneity associated with cell cycle.
The Ultrasound Review of Obstetrics & Gynecology, 2006
Objective. To describe the outcome of monochorionic twin pregnancies complicated by twin-twin tra... more Objective. To describe the outcome of monochorionic twin pregnancies complicated by twin-twin transfusion syndrome, managed in a single perinatal centre and treated with multidiode laser photocoagulation of abnormal placental communicating vessels. Material and Methods. From November 2002 to July 2004, 12 patients diagnosed with twin-twin transfusion syndrome were treated with multidiode laser photocoagulation (14 procedures). Monochorionic twin pregnancies with severe polyhydramnios in the recipient twin and strong oligohydramnios in donor twin is the key diagnostic feature in this syndrome; once diagnosed, severity of the syndrome was established following the classification reported by Quintero and cols. After laser therapy was completed we evaluated survival rates and complications associated with therapy. Results. Selective laser photocoagulation of communicating vessels was performed in 12 patients (14 procedures). In all these cases, both laser treatment and amnioreduction were carried out. The average number of abnormal placental communicating vessels was eight and average surgery time was 25 minutes. No maternal post-surgery complications were observed but there was a preterm premature rupture of membranes which most probably could be the cause of the subsequent miscarriage. Fetal survival rate of at least one twin to 28 days of age was 70%, while the number of deaths was associated to: 7 intrauterine deaths after surgical procedure, 2 neonatal deaths after preterm delivery and 2 deaths caused by a miscarriage after preterm rupture of membranes. Discussion. Twin-twin transfusion syndrome is a heterogeneous disorder in its clinical expression and progression. Laser photocoagulation is an efficient treatment for this syndrome, its spread and application in other centres would allow early management of this disorder, decreasing the fetus/neonatal morbidity and mortality rate. In this study we have applied a selective technique using a multidiode laser with results similar to those obtained in other studies that have been reported, which are survival rates between 50 to 76%.
2014 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS), 2014
High power density GaN HEMT technology can increase the capability of defense electronics systems... more High power density GaN HEMT technology can increase the capability of defense electronics systems with the reduction of CSWaP. However, thermal limitations have currently limited the inherent capabilities of this technology where transistor-level power densities that exceed 10 kW/cm 2 are electrically feasible. This paper introduces the concept of an evaporative microcooling device utilizing some of the current two-phase vapor separation technologies currently being developed for water and dielectric liquids.
Ultrasound in Obstetrics and Gynecology, 2007
Objectives Two methods have been proposed for standardizing measures of nuchal translucency thick... more Objectives Two methods have been proposed for standardizing measures of nuchal translucency thickness (NT) for risk calculation in first-trimester screening for chromosomal defects: differential delta NT (delta-NT) and multiples of the median (MoM) of NT. There is currently some debate as to which of these is more appropriate. The aims of this study were to determine whether delta-NT could be extrapolated successfully from one center-specific NT reference curve to another and thus to empirically calculate the likelihood ratios (LRs) of delta-NT. Methods This was a retrospective analysis of a database of 4248 singleton pregnancies, including 13 cases of Down syndrome. The delta-NT was extrapolated to the reference curve of the NT values of the original group of patients for whom the LRs were calculated empirically, using a scale factor. The Down syndrome risk was calculated by standardizing the NT, using both extrapolated delta-NT and MoM methods, both for the screening based on maternal age and NT alone, and for the combined screening, in which biochemical markers are also taken into account. We analyzed detection rates and false positives, the precision of the risk prediction obtained by each of the methods and the effectiveness when each of the methods was used with a cutoff point based on a fixed post-test risk. Results The risk calculation using extrapolated delta-NT presented an effectiveness profile that was similar to that obtained using MoMs, both when NT was used as the sole marker and when it was used in combination with biochemical markers. The precision of the risk prediction was similar with both methods. Conclusions Delta-NT can be extrapolated for use in risk calculation between two populations with different distributions and medians of NT values. The precision of the risk estimate obtained is similar to that derived using MoMs.
Prenatal Diagnosis, 2006
The aim of the present study is to determine whether the use of population parameters derived fro... more The aim of the present study is to determine whether the use of population parameters derived from meta-analysis produces better test characteristics in the first-trimester combined screening than those obtained from large single studies, when screening for Down syndrome (DS) in singleton pregnancies. Retrospective analysis was done on a database of 4248 singleton pregnancies, including 13 cases of DS, for which the values of three markers used in the combined first-trimester test were available. The risk of DS was calculated for each mother from the different population parameters derived by meta-analysis or from two large single studies: the Fetal Medicine Foundation study (FMF) and the Serum, Urine and Ultrasound Screening Study (SURUSS). When the detection rate was fixed at about 85%, the false-positive rate was significantly higher (Chi-square = 53.49, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) when the parameters obtained by the meta-analysis (6.25%) were compared with the two single studies (FMF, 4.15% and SURUSS, 3.75%). This study highlights the importance of selecting appropriate population parameters when insufficient DS cases are available in the study population. When screening for DS in singleton pregnancies during the first trimester, the use of population parameters derived from single large studies produced better test characteristics.
Prenatal Diagnosis, 2008
To analyze various possibilities of using dimeric inhibin A (DIA) as a first-trimester marker, du... more To analyze various possibilities of using dimeric inhibin A (DIA) as a first-trimester marker, during week 13, for diverse sequential strategies together with the combined test (CT) [which uses pregnancy-associated plasma protein A, free beta-human chorionic gonadotrophin and nuchal translucency]. We analyzed three sequential strategies (nondisclosure, stepwise and contingent) for measuring DIA in week 13. Multivariate Gaussian modelling was used to estimate second-trimester, false-positive and detection rates. Model parameters were taken from the Serum, Urine and Ultrasound Screening Study (SURUSS) assay. The three sequential strategies provided high and comparable levels of effectiveness, with false-positive rate for fixed detection rate of 85% and detection rate for fixed false-positive rate of 5% values of about 91 and 2%, respectively. The contingent strategy (with two CT risk cutoffs, of 1 in 50 and 1 in 2000) produced a screening-positive rate of 0.8% with CT, while only 23% of the women needed subsequent DIA measurement. First-trimester sequential screening using CT together with DIA measurement in week 13 is capable of producing results that are comparable with those of the integrated test, with the additional advantage that the final result is obtained earlier. It is recommended that this strategy be evaluated in large-scale prospective studies.
![Research paper thumbnail of Corrigendum to “Electrokinetics in nanochannels. Part I. Electric double layer overlap and channel-to-well equilibrium” [J. Colloid Interface Sci. 325 (2008) 526–538]](https://attachments.academia-assets.com/101957470/thumbnails/1.jpg)
](Journal of Colloid and Interface Science, 2009
International Journal of Heat and Mass Transfer, 2009
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright
International Journal of Gynecology & Obstetrics, 2006
Journal of Microelectromechanical Systems, 2000
A three-dimensional serpentine microchannel design with a "C-shaped" repeating unit is presented ... more A three-dimensional serpentine microchannel design with a "C-shaped" repeating unit is presented in this paper as a means of implementing chaotic advection to passively enhance fluid mixing. The device is fabricated in a silicon wafer using a double-sided KOH wet-etching technique to realize a three-dimensional channel geometry. Experiments using phenolphthalein and sodium hydroxide solutions demonstrate the ability of flow in this channel to mix faster and more uniformly than either pure molecular diffusion or flow in a "square-wave" channel for Reynolds numbers from 6 to 70. The mixing capability of the channel increases with increasing Reynolds number. At least 98% of the maximum intensity of reacted phenolphthalein is observed in the channel after five mixing segments for Reynolds numbers greater than 25. At a Reynolds number of 70, the serpentine channel produces 16 times more reacted phenolphthalein than a straight channel and 1.6 times more than the square-wave channel. Mixing rates in the serpentine channel at the higher Reynolds numbers are consistent with the occurrence of chaotic advection. Visualization of the interface formed in the channel between streams of water and ethyl alcohol indicates that the mixing is due to both diffusion and fluid stirring. [439] Index Terms-Chaotic advection, fluid mixing, microfuidics. I. INTRODUCTION R APID mixing is essential in many of the microfluidic systems targeted for use in biochemistry analysis, drug delivery, and sequencing or synthesis of nucleic acids, among others [1]-[3]. Biological processes such as cell activation, enzyme reactions, and protein folding often involve reactions that require mixing of reactants for initiation. Mixing is also necessary in many microfabricated chemical systems that carry out complex chemical synthesis [4], [5]. When the dimensions of a channel cross section are tens of micrometers, molecular diffusion can mix two fluid streams in just a few seconds. However, when the dimensions are several hundred micrometers, a molecular diffusion-based mixing process can take tens of seconds. Mixing is particularly inef-Manuscript
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2008
Few reports have been published of the current clinical management of anti-Kell alloimmunization ... more Few reports have been published of the current clinical management of anti-Kell alloimmunization in pregnancy; its low frequency of occurrence means that the few long series published have covered very ample time periods in which different kinds of clinical management have overlapped. The objective of the present paper is to present our experience in the current clinical management of pregnant women who are positive for the anti-Kell antibody. A retrospective analysis was carried out of the case histories of pregnant women who were alloimmunized for the Kell antigen and who were studied and/or treated at the Department of Fetal Medicine in the Virgen de las Nieves University Hospital in Granada (Spain), between 2000 and 2004. The clinical management included the basal measurement of the titre of antibodies, the identification of the paternal phenotype (and that of the fetus, if necessary), the ultrasonographic monitoring of the fetus to detect signs of anaemia, sampling of fetal blood by cordocentesis when fetal anaemia was suspected, and fetal intravascular transfusion when necessary. Of the 10 pregnancies with anti-Kell antibodies, The Kell antigen was confirmed in the fetus in three cases, in all of which moderate to severe fetal anaemia developed, requiring fetal intravascular transfusions. Although one of the fetus developed antenatal hydrops, a good perinatal result was advised. The current approach to anti-Kell alloimmunization enables pregnant women who have Kell-positive fetuses to be treated successfully.
ESAIM: Mathematical Modelling and Numerical Analysis, 2001
We present the combination of a state control and shape design approaches for the optimization of... more We present the combination of a state control and shape design approaches for the optimization of micro-fluidic channels used for sample extraction and separation of chemical species existing in a buffer solution. The aim is to improve the extraction and identification capacities of electroosmotic micro-fluidic devices by avoiding dispersion of the extracted advected band. Résumé. Nous présentons la combinaison de deux problèmes d'optimisation et de contrôle d'état pour les configurations de canaux micro-fluidique. Ces dispositifs sont utilisés pour l'extraction et la séparation de composants chimiques présents dans une solution. Le but est, dans un premier temps, l'amélioration de la phase de l'extraction par le contrôle de la dispersion du front. Ceci se fait par l'application d'un champsélectrique. L'on s'intèresse ensuiteà l'optimisation du canal, permettant la séparation, par une minimisation de la dispersion induite par les coudes.
Astronomy & Astrophysics, 2004
We present the first case of a highly collimated, extremely high velocity bipolar outflow in Taur... more We present the first case of a highly collimated, extremely high velocity bipolar outflow in Taurus. It is powered by the low-luminosity (0.4 L) source IRAS 04166+2706 and contains gas accelerated up to 50 km s −1 with respect to the ambient cloud both toward the blue and the red (uncorrected for projection). At the highest velocities, the outflow collimation factor exceeds 20, and the gas displays a very high degree of spatial symmetry. This very fast gas presents multiple maxima, and most likely arises from the acceleration of ambient material by a time-variable jet-like stellar wind. When scaled for luminosity, the outflow parameters of IRAS 04166 are comparable to those of other extremely high velocity outflows like L1448, indicating that even the very quiescent star-formation mode of Taurus can produce objects powering very high energy flows (L mec /L * > 0.15).
Astronomy & Astrophysics, 2004
L1521E seems unique among starless cores. It stands out in a distribution of a ratio (R) that we ... more L1521E seems unique among starless cores. It stands out in a distribution of a ratio (R) that we define to asses core evolution, and which compares the emission of the easily-depleted C 18 O molecule with that of the hard to deplete, late-time species N 2 H +. While all cores we have studied so far have R ratio lower than 1, L1521E has an R value of 3.4, which is 8 times the mean of the other cores. To understand this difference, we have modeled the C 18 O and N 2 H + abundance profiles in L1521E using a density distribution derived from 1.2 mm continuum data. Our model shows that the C 18 O emission in this core is consistent with constant abundance, and this makes L1521E the first core with no C 18 O depletion. Our model also derives an unusually low N 2 H + abundance. These two chemical peculiarities suggest that L1521E has contracted to its present density very recently, and it is therefore an extremely young starless core. Comparing our derived abundances with a chemical model, we estimate a tentative age of ≤1.5 × 10 5 yr, which is too short for ambipolar diffusion models.
Analytical Chemistry, 2007
Cuadernos De Economia, 2009
Proyecto académico sin fines de lucro, desarrollado bajo la iniciativa de acceso abierto
Memorie Della Societa Astronomica Italiana Supplementi, 2006
Protostars form in regions which are deeply hidden in molecular clouds and are surrounded by thic... more Protostars form in regions which are deeply hidden in molecular clouds and are surrounded by thick envelopes. Molecular outflows have the key to investigate the earliest evolutionary stages of star formation, especially at low luminosities where the outflow geometry can be relatively simple. In particular, the chemical changes induced by the passage of shocks associated with outflows can be used to try to establish an evolutionary scheme for outflows and consequently for the driving protostars. The main results obtained using mm-wavelength antennas during pilot projects focused on a small number of objects are shown. The strategy to carry on the project with the SRT is discussed.
Cierta clase de optimismo, o de supuesto optimismo, afirma que si nos esforzamos pensando, o si s... more Cierta clase de optimismo, o de supuesto optimismo, afirma que si nos esforzamos pensando, o si somos lo suficientemente racionales, podemos resolver todos nuestros problemas". H. A. Simon "En la medida en que se refieren a la realidad las proposiciones matemáticas no son ciertas, y en la medida en que son ciertas no se refieren a la realidad". Albert Einstein El siglo pasado dejó a su paso importantes desarrollos de la teoría económica, entre los que se destacan la teoría de la elección racional y el modelo 1 Juan Santiago es Magister en Educación y Magister(c) en Ingenieria financiera y estudiante del Doctorado en Ciencias Económicas. Se desempeña actualmente como profesor de probabilidad, inferencia y modelos de análisis estadísticos en la Facultad de
Microfluidics, BioMEMS, and Medical Microsystems XIII, 2015
Single cell analyses of RNA and DNA are crucial to understanding the heterogeneity of cell popula... more Single cell analyses of RNA and DNA are crucial to understanding the heterogeneity of cell populations. The numbers of approaches to single cells analyses are expanding, but sequence specific measurements of nucleic acids have been mostly limited to studies of either DNA or RNA, and not both. This remains a challenge as RNA and DNA have very similar physical and biochemical properties, and cross-contamination with each other can introduce false positive results. We present an electrokinetic technique which creates the opportunity to fractionate and deliver cytoplasmic RNA and genomic DNA to independent downstream analyses. Our technique uses an on-chip system that enables selective lysing of cytoplasmic membrane, extraction of RNA (away from genomic DNA and nucleus), focusing, absolute quantification of cytoplasmic RNA mass. The absolute RNA mass quantification is performed using fluorescence observation without enzymatic amplification in < 5 min. The cell nucleus is left intact and the relative genomic DNA amount in the nucleus can be measured. We demonstrate the technique using single mouse B lymphocyte cells, for which we extracted an average of 14.1 pg total cytoplasmic RNA per cell. We also demonstrate correlation analysis between the absolute amount of cytoplasmic RNA and relative amount of genomic DNA, showing heterogeneity associated with cell cycle.
The Ultrasound Review of Obstetrics & Gynecology, 2006
Objective. To describe the outcome of monochorionic twin pregnancies complicated by twin-twin tra... more Objective. To describe the outcome of monochorionic twin pregnancies complicated by twin-twin transfusion syndrome, managed in a single perinatal centre and treated with multidiode laser photocoagulation of abnormal placental communicating vessels. Material and Methods. From November 2002 to July 2004, 12 patients diagnosed with twin-twin transfusion syndrome were treated with multidiode laser photocoagulation (14 procedures). Monochorionic twin pregnancies with severe polyhydramnios in the recipient twin and strong oligohydramnios in donor twin is the key diagnostic feature in this syndrome; once diagnosed, severity of the syndrome was established following the classification reported by Quintero and cols. After laser therapy was completed we evaluated survival rates and complications associated with therapy. Results. Selective laser photocoagulation of communicating vessels was performed in 12 patients (14 procedures). In all these cases, both laser treatment and amnioreduction were carried out. The average number of abnormal placental communicating vessels was eight and average surgery time was 25 minutes. No maternal post-surgery complications were observed but there was a preterm premature rupture of membranes which most probably could be the cause of the subsequent miscarriage. Fetal survival rate of at least one twin to 28 days of age was 70%, while the number of deaths was associated to: 7 intrauterine deaths after surgical procedure, 2 neonatal deaths after preterm delivery and 2 deaths caused by a miscarriage after preterm rupture of membranes. Discussion. Twin-twin transfusion syndrome is a heterogeneous disorder in its clinical expression and progression. Laser photocoagulation is an efficient treatment for this syndrome, its spread and application in other centres would allow early management of this disorder, decreasing the fetus/neonatal morbidity and mortality rate. In this study we have applied a selective technique using a multidiode laser with results similar to those obtained in other studies that have been reported, which are survival rates between 50 to 76%.
2014 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS), 2014
High power density GaN HEMT technology can increase the capability of defense electronics systems... more High power density GaN HEMT technology can increase the capability of defense electronics systems with the reduction of CSWaP. However, thermal limitations have currently limited the inherent capabilities of this technology where transistor-level power densities that exceed 10 kW/cm 2 are electrically feasible. This paper introduces the concept of an evaporative microcooling device utilizing some of the current two-phase vapor separation technologies currently being developed for water and dielectric liquids.
Ultrasound in Obstetrics and Gynecology, 2007
Objectives Two methods have been proposed for standardizing measures of nuchal translucency thick... more Objectives Two methods have been proposed for standardizing measures of nuchal translucency thickness (NT) for risk calculation in first-trimester screening for chromosomal defects: differential delta NT (delta-NT) and multiples of the median (MoM) of NT. There is currently some debate as to which of these is more appropriate. The aims of this study were to determine whether delta-NT could be extrapolated successfully from one center-specific NT reference curve to another and thus to empirically calculate the likelihood ratios (LRs) of delta-NT. Methods This was a retrospective analysis of a database of 4248 singleton pregnancies, including 13 cases of Down syndrome. The delta-NT was extrapolated to the reference curve of the NT values of the original group of patients for whom the LRs were calculated empirically, using a scale factor. The Down syndrome risk was calculated by standardizing the NT, using both extrapolated delta-NT and MoM methods, both for the screening based on maternal age and NT alone, and for the combined screening, in which biochemical markers are also taken into account. We analyzed detection rates and false positives, the precision of the risk prediction obtained by each of the methods and the effectiveness when each of the methods was used with a cutoff point based on a fixed post-test risk. Results The risk calculation using extrapolated delta-NT presented an effectiveness profile that was similar to that obtained using MoMs, both when NT was used as the sole marker and when it was used in combination with biochemical markers. The precision of the risk prediction was similar with both methods. Conclusions Delta-NT can be extrapolated for use in risk calculation between two populations with different distributions and medians of NT values. The precision of the risk estimate obtained is similar to that derived using MoMs.
Prenatal Diagnosis, 2006
The aim of the present study is to determine whether the use of population parameters derived fro... more The aim of the present study is to determine whether the use of population parameters derived from meta-analysis produces better test characteristics in the first-trimester combined screening than those obtained from large single studies, when screening for Down syndrome (DS) in singleton pregnancies. Retrospective analysis was done on a database of 4248 singleton pregnancies, including 13 cases of DS, for which the values of three markers used in the combined first-trimester test were available. The risk of DS was calculated for each mother from the different population parameters derived by meta-analysis or from two large single studies: the Fetal Medicine Foundation study (FMF) and the Serum, Urine and Ultrasound Screening Study (SURUSS). When the detection rate was fixed at about 85%, the false-positive rate was significantly higher (Chi-square = 53.49, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) when the parameters obtained by the meta-analysis (6.25%) were compared with the two single studies (FMF, 4.15% and SURUSS, 3.75%). This study highlights the importance of selecting appropriate population parameters when insufficient DS cases are available in the study population. When screening for DS in singleton pregnancies during the first trimester, the use of population parameters derived from single large studies produced better test characteristics.
Prenatal Diagnosis, 2008
To analyze various possibilities of using dimeric inhibin A (DIA) as a first-trimester marker, du... more To analyze various possibilities of using dimeric inhibin A (DIA) as a first-trimester marker, during week 13, for diverse sequential strategies together with the combined test (CT) [which uses pregnancy-associated plasma protein A, free beta-human chorionic gonadotrophin and nuchal translucency]. We analyzed three sequential strategies (nondisclosure, stepwise and contingent) for measuring DIA in week 13. Multivariate Gaussian modelling was used to estimate second-trimester, false-positive and detection rates. Model parameters were taken from the Serum, Urine and Ultrasound Screening Study (SURUSS) assay. The three sequential strategies provided high and comparable levels of effectiveness, with false-positive rate for fixed detection rate of 85% and detection rate for fixed false-positive rate of 5% values of about 91 and 2%, respectively. The contingent strategy (with two CT risk cutoffs, of 1 in 50 and 1 in 2000) produced a screening-positive rate of 0.8% with CT, while only 23% of the women needed subsequent DIA measurement. First-trimester sequential screening using CT together with DIA measurement in week 13 is capable of producing results that are comparable with those of the integrated test, with the additional advantage that the final result is obtained earlier. It is recommended that this strategy be evaluated in large-scale prospective studies.
Journal of Colloid and Interface Science, 2009
International Journal of Heat and Mass Transfer, 2009
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright
International Journal of Gynecology & Obstetrics, 2006
Journal of Microelectromechanical Systems, 2000
A three-dimensional serpentine microchannel design with a "C-shaped" repeating unit is presented ... more A three-dimensional serpentine microchannel design with a "C-shaped" repeating unit is presented in this paper as a means of implementing chaotic advection to passively enhance fluid mixing. The device is fabricated in a silicon wafer using a double-sided KOH wet-etching technique to realize a three-dimensional channel geometry. Experiments using phenolphthalein and sodium hydroxide solutions demonstrate the ability of flow in this channel to mix faster and more uniformly than either pure molecular diffusion or flow in a "square-wave" channel for Reynolds numbers from 6 to 70. The mixing capability of the channel increases with increasing Reynolds number. At least 98% of the maximum intensity of reacted phenolphthalein is observed in the channel after five mixing segments for Reynolds numbers greater than 25. At a Reynolds number of 70, the serpentine channel produces 16 times more reacted phenolphthalein than a straight channel and 1.6 times more than the square-wave channel. Mixing rates in the serpentine channel at the higher Reynolds numbers are consistent with the occurrence of chaotic advection. Visualization of the interface formed in the channel between streams of water and ethyl alcohol indicates that the mixing is due to both diffusion and fluid stirring. [439] Index Terms-Chaotic advection, fluid mixing, microfuidics. I. INTRODUCTION R APID mixing is essential in many of the microfluidic systems targeted for use in biochemistry analysis, drug delivery, and sequencing or synthesis of nucleic acids, among others [1]-[3]. Biological processes such as cell activation, enzyme reactions, and protein folding often involve reactions that require mixing of reactants for initiation. Mixing is also necessary in many microfabricated chemical systems that carry out complex chemical synthesis [4], [5]. When the dimensions of a channel cross section are tens of micrometers, molecular diffusion can mix two fluid streams in just a few seconds. However, when the dimensions are several hundred micrometers, a molecular diffusion-based mixing process can take tens of seconds. Mixing is particularly inef-Manuscript
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2008
Few reports have been published of the current clinical management of anti-Kell alloimmunization ... more Few reports have been published of the current clinical management of anti-Kell alloimmunization in pregnancy; its low frequency of occurrence means that the few long series published have covered very ample time periods in which different kinds of clinical management have overlapped. The objective of the present paper is to present our experience in the current clinical management of pregnant women who are positive for the anti-Kell antibody. A retrospective analysis was carried out of the case histories of pregnant women who were alloimmunized for the Kell antigen and who were studied and/or treated at the Department of Fetal Medicine in the Virgen de las Nieves University Hospital in Granada (Spain), between 2000 and 2004. The clinical management included the basal measurement of the titre of antibodies, the identification of the paternal phenotype (and that of the fetus, if necessary), the ultrasonographic monitoring of the fetus to detect signs of anaemia, sampling of fetal blood by cordocentesis when fetal anaemia was suspected, and fetal intravascular transfusion when necessary. Of the 10 pregnancies with anti-Kell antibodies, The Kell antigen was confirmed in the fetus in three cases, in all of which moderate to severe fetal anaemia developed, requiring fetal intravascular transfusions. Although one of the fetus developed antenatal hydrops, a good perinatal result was advised. The current approach to anti-Kell alloimmunization enables pregnant women who have Kell-positive fetuses to be treated successfully.
ESAIM: Mathematical Modelling and Numerical Analysis, 2001
We present the combination of a state control and shape design approaches for the optimization of... more We present the combination of a state control and shape design approaches for the optimization of micro-fluidic channels used for sample extraction and separation of chemical species existing in a buffer solution. The aim is to improve the extraction and identification capacities of electroosmotic micro-fluidic devices by avoiding dispersion of the extracted advected band. Résumé. Nous présentons la combinaison de deux problèmes d'optimisation et de contrôle d'état pour les configurations de canaux micro-fluidique. Ces dispositifs sont utilisés pour l'extraction et la séparation de composants chimiques présents dans une solution. Le but est, dans un premier temps, l'amélioration de la phase de l'extraction par le contrôle de la dispersion du front. Ceci se fait par l'application d'un champsélectrique. L'on s'intèresse ensuiteà l'optimisation du canal, permettant la séparation, par une minimisation de la dispersion induite par les coudes.
Astronomy & Astrophysics, 2004
We present the first case of a highly collimated, extremely high velocity bipolar outflow in Taur... more We present the first case of a highly collimated, extremely high velocity bipolar outflow in Taurus. It is powered by the low-luminosity (0.4 L) source IRAS 04166+2706 and contains gas accelerated up to 50 km s −1 with respect to the ambient cloud both toward the blue and the red (uncorrected for projection). At the highest velocities, the outflow collimation factor exceeds 20, and the gas displays a very high degree of spatial symmetry. This very fast gas presents multiple maxima, and most likely arises from the acceleration of ambient material by a time-variable jet-like stellar wind. When scaled for luminosity, the outflow parameters of IRAS 04166 are comparable to those of other extremely high velocity outflows like L1448, indicating that even the very quiescent star-formation mode of Taurus can produce objects powering very high energy flows (L mec /L * > 0.15).
Astronomy & Astrophysics, 2004
L1521E seems unique among starless cores. It stands out in a distribution of a ratio (R) that we ... more L1521E seems unique among starless cores. It stands out in a distribution of a ratio (R) that we define to asses core evolution, and which compares the emission of the easily-depleted C 18 O molecule with that of the hard to deplete, late-time species N 2 H +. While all cores we have studied so far have R ratio lower than 1, L1521E has an R value of 3.4, which is 8 times the mean of the other cores. To understand this difference, we have modeled the C 18 O and N 2 H + abundance profiles in L1521E using a density distribution derived from 1.2 mm continuum data. Our model shows that the C 18 O emission in this core is consistent with constant abundance, and this makes L1521E the first core with no C 18 O depletion. Our model also derives an unusually low N 2 H + abundance. These two chemical peculiarities suggest that L1521E has contracted to its present density very recently, and it is therefore an extremely young starless core. Comparing our derived abundances with a chemical model, we estimate a tentative age of ≤1.5 × 10 5 yr, which is too short for ambipolar diffusion models.
Analytical Chemistry, 2007