A case-control study of tea/coffee consumption and lung cancer risk

Background. Despite the increasing attention to the effects of dietary factors on lung cancer risk, epidemiological research on the role of black/green tea and coffee intake and lung cancer risk is scarce. The purpose of this study was to explore the following three hypotheses: (1) the preventive (protective) effect from lung cancer is higher in green tea than in black tea and coffee consumption. (2) brewed tea (either black or green) daily drinkers have lower odds of lung cancer than non-drinkers of brewed tea (3) regular black and green tea have more preventive effect against lung cancer than decaffeinated teas due to the synergistic effect of caffeine and other tea components. ^ Methods. Data on 1,088 lung cancer cases and 1,127 controls from an ongoing epidemiological study of lung cancer by the Department of Epidemiology of the University of Texas M.D. Anderson Cancer were analyzed. Multiple logistic regressions were performed for testing associations between frequency of specific types of tea/coffee consumption and the risk of lung cancer. ^ Results. We observed that more than a cup a week of green tea and decaffeinated black tea were significantly associated with reduced odds of lung cancer by 64% for green tea (adjusted OR = 0.44; 95% CI = 0.31–0.64), 36% for decaffeinated black tea (OR = 0.64; 95% CI = 0.45–0.90), when compared with non-drinkers and those who drank less than a cup a week. On the other hand, increasing intake of regular coffee (more than 3 cups a day) was associated with a 30% higher odds ratio of lung cancer (OR = 1.30; 95% CI = 1.01–1.09). No association was found between regular black tea, decaffeinated coffee consumption and the odds ratio of lung cancer. However, when drinkers of other tea/coffee beverages were excluded from each model in order to explore the independent effect of each type of tea/coffee, green tea and decaffeinated black tea-lung cancer associations remained but no association was observed for drinkers of regular coffee. ^ Conclusion. We report the chemopreventive effects of more than a cup a week of green tea and decaffeinated black tea on lung cancer. ^

Attention-Deficit/Hyperactivity Disorder and antidepressants and prescription medications: A pilot study

Background. Attention Deficit-Hyperactivity Disorder (AD/HD) diagnosis in children and adolescents has been on the rise over the last couple of decades and a multitude of studies have been conducted in an aim to better understand the disease. Literature has explored the role of several factors suspected of contributing to development of the disease, including: prenatal smoking exposures, environmental exposures, and low-birth weight. However, there is very limited reporting of fetal/infant exposure to antidepressants and prescription medications and the long-term behavioral outcomes, namely development of AD/HD. The purpose of this study was to evaluate the relationship between mother's exposure to prescription medications and/or antidepressants around the time of conception, during pregnancy, or while breastfeeding and the development of Attention-Deficit/Hyperactivity Disorder in offspring. Methods. Secondary analysis of data from a case-control study was performed. Exposure histories were collected for the mother and offspring. Data were collected using a secure, confidential, self-report, online survey to evaluate the relationship between antidepressant and/or prescription medication exposure and the development of AD/HD. The period of exposure to these drugs was defined as: around the time of conception, during pregnancy, or while breastfeeding. Cases were defined as a child who had been diagnosed with AD/HD. Controls were defined as a child who had not been diagnosed with AD/HD. Results. Prescription medication and antidepressant medication exposures around the time of conception, during pregnancy, or while breastfeeding were not associated with development of AD/HD. However, traumatic brain injury (OR=2.77 (1.61–4.77)) and preterm birth (OR=1.48 (1.04–2.12)) were identified as potential risk factors. These results support existing literature on AD/HD, but future work must be undertaken to better evaluate fetal/infant medication exposures and long-term behavioral outcomes.^

The association of allergies and attention deficit hyperactivity disorder in children

To investigate the association between allergies and attention deficit hyperactivity disorder (ADHD), a case-control study was conducted using the National Longitudinal Survey of Youth population. Cases were between the ages of 4 and 11 years and were classified either by a maternal-reported diagnosis or by the Behavior Problems Index Hyperactivity Scale. Controls were chosen from the same age group but had a score of less than 14 on the overall Behavior Problems Index. A history of allergies was considered positive if any of the following conditions were reported as requiring treatment by a doctor or other health professional: asthma, allergic conditions, or food allergies. A strong association was observed between allergies and a maternal-reported diagnosis while controlling for demographic, socioeconomic, perinatal, and environmental factors (adjusted odds ratio = 2.85 (95% CI = 1.49-5.42)). Other risk factors found to be important risk factors for a diagnosis of ADHD were gender (male), gestational age ($<$36 weeks), and maternal education ($\leq$high school). No association between allergies and cases classified as ADHD based on the hyperactivity symptom scale was observed. This study confirms other studies that reported an allergy/ADHD association in diagnoses populations. Further investigation confirming the association and explanation of the reasons and underlying mechanisms of the observed association is warranted. These studies should use validated diagnostic criteria for the diagnosis of ADHD symptoms and allergies, adequate sample sizes, and control for confounding. ^

Natural history of placebo treatment in adults acquiring travelers' diarrhea in Mexico

The natural history of placebo treated travelers' diarrhea and the prognostic factors of recovery from diarrhea were evaluated using 9 groups of placebo treated subjects from 9 clinical trial studies conducted since 1975, for use as a historical control in the future clinical trial of antidiarrheal agents. All of these studies were done by the same group of investigators in one site (Guadalajara, Mexico). The studies are similar in terms of population, measured parameters, microbiologic identification of enteropathogens and definitions of parameters. The studies had two different durations of followup. In some studies, subjects were followed for two days, and in some they were followed for five days.^ Using definitions established by the Infectious Diseases society of America and the Food and Drug Administration, the following efficacy parameters were evaluated: Time to last unformed stool (TLUS), number of unformed stools post-initiation of placebo treatment for five consecutive days of followup, microbiologic cure, and improvement of diarrhea. Among the groups that were followed for five days, the mean TLUS ranged from 59.1 to 83.5 hours. Fifty percent to 78% had diarrhea lasting more than 48 hours and 25% had diarrhea more than five days. The mean number of unformed stools passed on the first day post-initiation of therapy ranged from 3.6 to 5.8 and, for the fifth day ranged from 0.5 to 1.5. By the end of followup, diarrhea improved in 82.6% to 90% of the subjects. Subjects with enterotoxigenic E. coli had 21.6% to 90.0% microbiologic cure; and subjects with shigella species experienced 14.3% to 60.0% microbiologic cure.^ In evaluating the prognostic factors of recovery from diarrhea (primary efficacy parameter in evaluating the efficacy of antidiarrheal agents against travelers' diarrhea). The subjects from five studies were pooled and the Cox proportional hazard model was used to evaluate the predictors of prolonged diarrhea. After adjusting for design characteristics of each trial, fever with a rate ratio (RR) of 0.40, presence of invasive pathogens with a RR of 0.41, presence of severe abdominal pain and cramps with a RR of 0.50, number of watery stools more than five with a RR of 0.60, and presence of non-invasive pathogens with a RR of 0.84 predicted a longer duration of diarrhea. Severe vomiting with a RR of 2.53 predicted a shorter duration of diarrhea. The number of soft stools, presence of fecal leukocytes, presence of nausea, and duration of diarrhea before enrollment were not associated with duration of diarrhea. ^

Attention-deficit hyperactivity disorder symptoms and lead exposure in children: A systematic review of literature

Blood lead levels > 10 µg/dL are known to affect various areas of the brain that influence behavior and cause many other health problems in children. As a result, the Centers for Disease Control and Prevention (CDC) set the blood lead action level at 10 µg/dL. However, recent research provides evidence that blood lead levels <10 µg/dL also may lead to behavioral problems in children. With the recent increase in diagnosis of Attention-Deficit Hyperactivity Disorder (ADHD) in children in the U.S. it is important to determine possible environmental toxins such as lead that may play a role in causing ADHD symptoms. The aim of this systematic review of the literature was to identify recent published studies that examine an association between blood lead levels < 10 µg/dL and ADHD symptoms in children in order to summarize their findings and describe major gaps in the literature. Although available research is limited, the articles reviewed indicate that blood lead at levels much below the CDC action level of 10 µg/dL may affect a child's level of attention, hyperactivity, impulsivity and ADHD diagnosis. Additional prospective research is warranted in order to inform the revision of current blood lead action levels as well as better elucidate the relationship between lead and ADHD diagnoses.^

Current Mode with RMS Voltage and Offset Control Loops for a Single-Phase Aircraft Inverter Suitable for Parallel and 3-Phase Operation Modes

Rms voltage regulation may be an attractive possibility for controlling power inverters. Combined with a Hall Effect sensor for current control, it keeps its parallel operation capability while increasing its noise immunity, which may lead to a reduction of the Total Harmonic Distortion (THD). Besides, as voltage regulation is designed in DC, a simple PI regulator can provide accurate voltage tracking. Nevertheless, this approach does not lack drawbacks. Its narrow voltage bandwidth makes transients last longer and it increases the voltage THD when feeding non-linear loads, such as rectifying stages. On the other hand, the implementation can fall into offset voltage error. Furthermore, the information of the output voltage phase is hidden for the control as well, making the synchronization of a 3-phase setup not trivial. This paper explains the concept, design and implementation of the whole control scheme, in an on board inverter able to run in parallel and within a 3-phase setup. Special attention is paid to solve the problems foreseen at implementation level: a third analog loop accounts for the offset level is added and a digital algorithm guarantees 3-phase voltage synchronization.

Effects of binaural stimulation in attention and EEG

When two pure tones of slightly different frequency are presented separately to each ear, the listener perceives a third single tone with amplitude variations at a frequency that equals the difference between the two tones, this perceptual illusion is known as binaural auditory beat. There are anecdotal reports that suggest that the binaural beat can entrain EEG activity and may affect the arousal levels, although few studies have been published. There is a need for double-blind, well-designed studies in order to establish a solid foundation for these sounds, as most of the documented benefits come from self-reported cases that could be affected by placebo effect. As BB’s are a cheap technology (it even exists a free open source programmable bin aural-beat generator on the internet named Gnaural), any achievement in this area could be of public interest. The aim in our research was to explore the potential of BB’s in a particular field: tasks that require focus and concentration. In order to detect changes in the brain waves that could relate to any particular improvement, EEG recordings of a small sample of individuals were also obtained. In this study we compare the effect of different binaural stimulation in 7 EEG frequency ranges, 78 participants were exposed to 20 min binaural beat stimulation. The effects were obtained both qualitative with cognitive test and quantitative with EEG analysis. Results suggest no significant statistical improvement in 20 min stimulation.

Impedance control for legged robots: an insight into the concepts involved

The application of impedance control strategies to modern legged locomotion is analyzed, paying special attention to the concepts behind its implementation which is not straightforward. In order to implement a functional impedance controller for a walking mechanism, the concepts of contact, impact, friction, and impedance have to be merged together. A literature review and a comprehensive analysis are presented compiling all these concepts along with a discussion on position-based versus force-based impedance control approaches, and a theoretical model of a robotic leg in contact with its environment is introduced. A theoretical control scheme for the legs of a general legged robot is also introduced, and some simulations results are presented.

Effect of binaural stimulation on attention and EEG

When two pure tones of slightly different frequency are presented separately to each ear, the listener perceives a third single tone with amplitude variations at a frequency that equals the difference between the two tones; this perceptual illusion is known as the binaural auditory beat (BB). There are anecdotal reports that suggest that the binaural beat can entrain EEG activity and may affect the arousal levels, although few studies have been published. There is a need for double-blind, well-designed studies in order to establish a solid foundation for these sounds, as most of the documented benefits come from self-reported cases that could be affected by placebo effect. As BBs are a cheap technology (it even exists a free open source programmable binaural- beat generator on the Internet named Gnaural), any achievement in this area could be of public interest. The aim in our research was to explore the potential of BBs in a particular field: tasks that require focus and concentration. In order to detect changes in the brain waves that could relate to any particular improvement, EEG recordings of a small sample of individuals were also obtained. In this study we compare the effect of different binaural stimulation in 7 EEG frequency ranges. 78 participants were exposed to 20-min binaural beat stimulation. The effects were obtained both quali- tative with cognitive test and quantitative with EEG analysis. Results suggest no significant statistical improvement in 20-min stimulation.

Analytical models for the power subsystem and the attitude control subsystem of a microsatellite

El trabajo realizado en la presente tesis doctoral se debe considerar parte del proyecto UPMSat-2, que se enmarca dentro del ámbito de la tecnología aeroespacial. El UPMSat-2 es un microsatélite (de bajo coste y pequeño tamaño) diseñado, construido, probado e integrado por la Universidad Politécnica de Madrid (España), para fines de demostración tecnológica y educación. El objetivo de la presente tesis doctoral es presentar nuevos modelos analíticos para estudiar la interdependencia energética entre los subsistemas de potencia y de control de actitud de un satélite. En primer lugar, se estudia la simulación del subsistema de potencia de un microsatélite, prestando especial atención a la simulación de la fuente de potencia, esto es, los paneles solares. En la tesis se presentan métodos sencillos pero precisos para simular la producción de energía de los paneles en condiciones ambientales variables a través de su circuito equivalente. Los métodos propuestos para el cálculo de los parámetros del circuito equivalente son explícitos (o al menos, con las variables desacopladas), no iterativos y directos; no se necesitan iteraciones o valores iniciales para calcular los parámetros. La precisión de este método se prueba y se compara con métodos similares de la literatura disponible, demostrando una precisión similar para mayor simplicidad. En segundo lugar, se presenta la simulación del subsistema de control de actitud de un microsatélite, prestando especial atención a la nueva ley de control propuesta. La tesis presenta un nuevo tipo de control magnético es aplicable a la órbita baja terrestre (LEO). La ley de control propuesta es capaz de ajustar la velocidad de rotación del satélite alrededor de su eje principal de inercia máximo o mínimo. Además, en el caso de órbitas de alta inclinación, la ley de control favorece la alineación del eje de rotación con la dirección normal al plano orbital. El algoritmo de control propuesto es simple, sólo se requieren magnetopares como actuadores; sólo se requieren magnetómetros como sensores; no hace falta estimar la velocidad angular; no incluye un modelo de campo magnético de la Tierra; no tiene por qué ser externamente activado con información sobre las características orbitales y permite el rearme automático después de un apagado total del subsistema de control de actitud. La viabilidad teórica de la citada ley de control se demuestra a través de análisis de Monte Carlo. Por último, en términos de producción de energía, se demuestra que la actitud propuesto (en eje principal perpendicular al plano de la órbita, y el satélite que gira alrededor de ella con una velocidad controlada) es muy adecuado para la misión UPMSat-2, ya que permite una área superior de los paneles apuntando hacia el sol cuando se compara con otras actitudes estudiadas. En comparación con el control de actitud anterior propuesto para el UPMSat-2 resulta en un incremento de 25% en la potencia disponible. Además, la actitud propuesto mostró mejoras significativas, en comparación con otros, en términos de control térmico, como la tasa de rotación angular por satélite puede seleccionarse para conseguir una homogeneización de la temperatura más alta que apunta satélite y la antena. ABSTRACT The work carried out in the present doctoral dissertation should be considered part of the UPMSat-2 project, falling within the scope of the aerospace technology. The UPMSat-2 is a microsatellite (low cost and small size) designed, constructed integrated and tested for educational and technology demonstration purposes at the Universidad Politécnica de Madrid (Spain). The aim of the present doctoral dissertation is to present new analytical models to study the energy interdependence between the power and the attitude control subsystems of a satellite. First, the simulation of the power subsystem of a microsatellite is studied, paying particular attention to the simulation of the power supply, i.e. the solar panels. Simple but accurate methods for simulate the power production under variable ambient conditions using its equivalent circuit are presented. The proposed methods for calculate the equivalent circuit parameters are explicit (or at least, with decoupled variables), non-iterative and straight forward; no iterations or initial values for the parameters are needed. The accuracy of this method is tested and compared with similar methods from the available literature demonstrating similar precision but higher simplicity. Second, the simulation of the control subsystem of a microsatellite is presented, paying particular attention to the new control law proposed. A new type of magnetic control applied to Low Earth Orbit (LEO) satellites has been presented. The proposed control law is able to set the satellite rotation speed around its maximum or minimum inertia principal axis. Besides, the proposed control law favors the alignment of this axis with the normal direction to the orbital plane for high inclination orbits. The proposed control algorithm is simples, only magnetorquers are required as actuators; only magnetometers are required as sensors; no estimation of the angular velocity is needed; it does not include an in-orbit Earth magnetic field model; it does not need to be externally activated with information about the orbital characteristics and it allows automatic reset after a total shutdown of attitude control subsystem. The theoretical viability of the control law is demonstrated through Monte Carlo analysis. Finally, in terms of power production, it is demonstrated that the proposed attitude (on principal axis perpendicular to the orbit plane, and the satellite rotating around it with a controlled rate) is quite suitable for the UPMSat-2 mission, as it allows a higher area of the panels pointing towards the sun when compared to other studied attitudes. Compared with the previous attitude control proposed for the UPMSat-2 it results in a 25% increment in available power. Besides, the proposed attitude showed significant improvements, when compared to others, in terms of thermal control, as the satellite angular rotation rate can be selected to achieve a higher temperature homogenization of the satellite and antenna pointing.

Global instability analysis and control of three-dimensional long open cavity flow

The three-dimensional wall-bounded open cavity may be considered as a simplified geometry found in industrial applications such as leading gear or slotted flats on the airplane. Understanding the three-dimensional complex flow structure that surrounds this particular geometry is therefore of major industrial interest. At the light of the remarkable former investigations in this kind of flows, enough evidences suggest that the lateral walls have a great influence on the flow features and hence on their instability modes. Nevertheless, even though there is a large body of literature on cavity flows, most of them are based on the assumption that the flow is two-dimensional and spanwise-periodic. The flow over realistic open cavity should be considered. This thesis presents an investigation of three-dimensional wall-bounded open cavity with geometric ratio 6:2:1. To this aim, three-dimensional Direct Numerical Simulation (DNS) and global linear instability have been performed. Linear instability analysis reveals that the onset of the first instability in this open cavity is around Recr 1080. The three-dimensional shear layer mode with a complex structure is shown to be the most unstable mode. I t is noteworthy that the flow pattern of this high-frequency shear layer mode is similar to the observed unstable oscillations in supercritical unstable case. DNS of the cavity flow carried out at different Reynolds number from steady state until a nonlinear saturated state is obtained. The comparison of time histories of kinetic energy presents a clearly dominant energetic mode which shifts between low-frequency and highfrequency oscillation. A complete flow patterns from subcritical cases to supercritical case has been put in evidence. The flow structure at the supercritical case Re=1100 resembles typical wake-shedding instability oscillations with a lateral motion existed in the subcritical cases. Also, This flow pattern is similar to the observations in experiments. In order to validate the linear instability analysis results, the topology of the composite flow fields reconstructed by linear superposition of a three-dimensional base flow and its leading three-dimensional global eigenmodes has been studied. The instantaneous wall streamlines of those composited flows display distinguish influence region of each eigenmode. Attention has been focused on the leading high-frequency shear layer mode; the composite flow fields have been fully recognized with respect to the downstream wave shedding. The three-dimensional shear layer mode is shown to give rise to a typical wake-shedding instability with a lateral motions occurring downstream which is in good agreement with the experiment results. Moreover, the spanwise-periodic, open cavity with the same length to depth ratio has been also studied. The most unstable linear mode is different from the real three-dimensional cavity flow, because of the existence of the side walls. Structure sensitivity of the unstable global mode is analyzed in the flow control context. The adjoint-based sensitivity analysis has been employed to localized the receptivity region, where the flow is more sensible to momentum forcing and mass injection. Because of the non-normality of the linearized Navier-Stokes equations, the direct and adjoint field has a large spatial separation. The strongest sensitivity region is locate in the upstream lip of the three-dimensional cavity. This numerical finding is in agreement with experimental observations. Finally, a prototype of passive flow control strategy is applied.

The impact of cognitive control on children's goal monitoring in a time-based prospective memory task

Peer reviewed

Selective effects of methylphenidate in attention deficit hyperactivity disorder: A functional magnetic resonance study

Functional MRI revealed differences between children with Attention Deficit Hyperactivity Disorder (ADHD) and healthy controls in their frontal–striatal function and its modulation by methylphenidate during response inhibition. Children performed two go/no-go tasks with and without drug. ADHD children had impaired inhibitory control on both tasks. Off-drug frontal–striatal activation during response inhibition differed between ADHD and healthy children: ADHD children had greater frontal activation on one task and reduced striatal activation on the other task. Drug effects differed between ADHD and healthy children: The drug improved response inhibition in both groups on one task and only in ADHD children on the other task. The drug modulated brain activation during response inhibition on only one task: It increased frontal activation to an equal extent in both groups. In contrast, it increased striatal activation in ADHD children but reduced it in healthy children. These results suggest that ADHD is characterized by atypical frontal–striatal function and that methylphenidate affects striatal activation differently in ADHD than in healthy children.

Two Distinct Mechanisms Control the Accumulation of Cyclin B1 and Mos in Xenopus Oocytes in Response to Progesterone

Progesterone-induced meiotic maturation of Xenopus oocytes requires the synthesis of new proteins, such as Mos and cyclin B. Synthesis of Mos is thought to be necessary and sufficient for meiotic maturation; however, it has recently been proposed that newly synthesized proteins binding to p34cdc2 could be involved in a signaling pathway that triggers the activation of maturation-promoting factor. We focused our attention on cyclin B proteins because they are synthesized in response to progesterone, they bind to p34cdc2, and their microinjection into resting oocytes induces meiotic maturation. We investigated cyclin B accumulation in response to progesterone in the absence of maturation-promoting factor–induced feedback. We report here that the cdk inhibitor p21cip1, when microinjected into immature Xenopus oocytes, blocks germinal vesicle breakdown induced by progesterone, by maturation-promoting factor transfer, or by injection of okadaic acid. After microinjection of p21cip1, progesterone fails to induce the activation of MAPK or p34cdc2, and Mos does not accumulate. In contrast, the level of cyclin B1 increases normally in a manner dependent on down-regulation of cAMP-dependent protein kinase but independent of cap-ribose methylation of mRNA.

Local and global attention are mapped retinotopically in human occipital cortex

Clinical evidence suggests that control mechanisms for local and global attention are lateralized in the temporal–parietal cortex. However, in the human occipital (visual) cortex, the evidence for lateralized local/global attention is controversial. To clarify this matter, we used functional MRI to map activity in the human occipital cortex, during local and global attention, with sustained visual fixation. Data were analyzed in a flattened cortical format, relative to maps of retinotopy and spatial frequency peak tuning. Neither local nor global attention was lateralized in the occipital cortex. Instead, local attention and global attention appear to be special cases of visual spatial attention, which are mapped consistently with the maps of retinotopy and spatial frequency tuning, in multiple visual cortical areas.