David Martín - Academia.edu (original) (raw)

Papers by David Martín

Electronics, 2020

The advances in autonomous technologies and microelectronics have increased the use of Autonomous... more The advances in autonomous technologies and microelectronics have increased the use of Autonomous Unmanned Aerial Vehicles (UAVs) in more critical applications, such as forest fire monitoring and fighting. In addition, implementing surveillance methods that provide rich information about the fires is considered a great tool for Emergency Response Teams (ERT). From this aspect and in collaboration with Telefónica Digital España, Dronitec S.L, and Divisek Systems, this paper presents a fire monitoring system based on perception algorithms, implemented on a UAV, to perform surveillance tasks allowing the monitoring of a specific area, in which several algorithms have been implemented to perform the tasks of autonomous take-off/landing, trajectory planning, and fire monitoring. This UAV is equipped with RGB and thermal cameras, temperature sensors, and communication modules in order to provide full information about the fire and the UAV itself, sending these data to the ground station i...

Current topics in behavioral neurosciences, Jan 5, 2017

The classic serotonergic hallucinogens, or psychedelics, have the ability to profoundly alter per... more The classic serotonergic hallucinogens, or psychedelics, have the ability to profoundly alter perception and behavior. These can include visual distortions, hallucinations, detachment from reality, and mystical experiences. Some psychedelics, like LSD, are able to produce these effects with remarkably low doses of drug. Others, like psilocybin, have recently been demonstrated to have significant clinical efficacy in the treatment of depression, anxiety, and addiction that persist for at least several months after only a single therapeutic session. How does this occur? Much work has recently been published from imaging studies showing that psychedelics alter brain network connectivity. They facilitate a disintegration of the default mode network, producing a hyperconnectivity between brain regions that allow centers that do not normally communicate with each other to do so. The immediate and acute effects on both behaviors and network connectivity are likely mediated by effector path...

Arthritis & rheumatology (Hoboken, N.J.), May 24, 2017

Interferon (IFN)-γ is implicated in the pathogenesis of discoid lupus erythematosus (DLE). This s... more Interferon (IFN)-γ is implicated in the pathogenesis of discoid lupus erythematosus (DLE). This study evaluated a single dose of AMG 811, an anti-IFN-γ antibody, in subjects with DLE. This was a phase 1, randomized, double-blind, placebo-controlled, crossover study (sequence 1: AMG 811 followed by placebo; sequence 2: placebo followed by AMG 811). Subjects received a single subcutaneous dose of AMG 811 (180 mg) or placebo. Pharmacodynamic endpoints included global transcriptional analyses of lesional and nonlesional skin, IFN-γ Blockade Signature (IGBS) transcriptional score in skin and blood, keratinocyte IFN-γ RNA score, and serum CXCL-10 protein. Additional endpoints included efficacy (including Cutaneous Lupus Erythematosus Disease Area and Severity Index; CLASI(TM) ) and safety outcomes. Sixteen subjects enrolled (9 in sequence 1; 7 in sequence 2) in this study. AMG 811 treatment reduced the IGBS score (elevated at baseline) in both blood and lesional skin. The keratinocyte IFN...

Rheumatology (Oxford, England), Dec 1, 2016

IL-17 cytokines are expressed by a variety of cells and mediate host defence against extracellula... more IL-17 cytokines are expressed by a variety of cells and mediate host defence against extracellular pathogens. IL-17 is upregulated at sites of inflammation and can synergize with other cytokines, such as TNF-α, to amplify the inflammatory response. Activation of these signalling pathways has been hypothesized to contribute to the underlying pathogenesis of several inflammatory diseases, including psoriasis, RA, PsA and asthma. Thus the IL-17 signalling pathway is an attractive target for the development of therapeutic agents to modulate aberrant inflammatory responses. This review of the clinical development of therapeutic agents that target IL-17 signalling pathways in inflammatory diseases focuses on brodalumab, a human anti-IL-17 receptor A mAb. The cumulative findings of early clinical studies with anti-IL-17 agents, including brodalumab, secukinumab and ixekizumab, provide strong evidence for the role of IL-17 signalling in the pathophysiology of certain inflammatory diseases a...

EBioMedicine, Jan 3, 2016

There has recently been a resurgence of interest in psychedelics, substances that profoundly alte... more There has recently been a resurgence of interest in psychedelics, substances that profoundly alter perception and cognition and have recently demonstrated therapeutic efficacy to treat anxiety, depression, and addiction in the clinic. The receptor mechanisms that drive their molecular and behavioral effects involve activation of cortical serotonin 5-HT2A receptors, but the responses of specific cellular populations remain unknown. Here, we provide evidence that a small subset of 5-HT2A-expressing excitatory neurons is directly activated by psychedelics and subsequently recruits other select cell types including subpopulations of inhibitory somatostatin and parvalbumin GABAergic interneurons, as well as astrocytes, to produce distinct and regional responses. To gather data regarding the response of specific neuronal populations, we developed methodology for fluorescence-activated cell sorting (FACS) to segregate and enrich specific cellular subtypes in the brain. These methods allow ...

The Journal of Cell Biology, 1999

Insulin-like growth factor (IGF) II is overexpressed in many human cancers and is reactivated by,... more Insulin-like growth factor (IGF) II is overexpressed in many human cancers and is reactivated by, and crucial for viral oncogene (SV40 T antigen, [TAg])–induced tumorigenesis in several tumor models. Using a double transgenic murine hepatic tumor model, we demonstrate that tissue inhibitor of metalloproteinase 1 (TIMP-1) blocks liver hyperplasia during tumor development, despite TAg-mediated reactivation of IGF-II. Because the activity of IGFs is controlled by IGF-binding proteins (IGFBPs), we investigated whether TIMP-1 overexpression altered the IGFBP status in the transgenic liver. Ligand blotting showed that IGFBP-3 protein levels were increased in TIMP-1–overexpressing double transgenic littermates, whereas IGFBP-3 mRNA levels were not different, suggesting that TIMP-1 affects IGFBP-3 at a posttranscriptional level. IGFBP-3 proteolysis assays demonstrated that IGFBP-3 degradation was lower in TIMP-1–overexpressing livers, and zymography showed that matrix metalloproteinases (MM...

Robotics and Autonomous Systems, 2016

Autonomous vehicles rely on the accurate estimation of their pose, speed and direction of travel ... more Autonomous vehicles rely on the accurate estimation of their pose, speed and direction of travel to perform basic navigation tasks. Although GPSs are very useful, they have some drawbacks in urban applications that affect their accuracy. Visual odometry is an alternative or complementary method because provides the ego motion of the vehicle with enough accuracy and uses a sensor already available in some vehicles for other tasks, so no extra sensor is needed. In this paper, a new method is proposed that detects and tracks features available on the surface of the ground, due to the texture of the road or street and road markings. This way it is assured only static points are taking into account in order to obtain the relative movement between images. A Kalman filter improves the estimations and the Ackermann steering restriction is applied so the vehicle follows a constrained trajectory, which improves the camera displacement estimation obtain from a PnP algorithm. Some results in real urban environments are shown in order to demonstrate the good performance of the algorithm. They show the method is able to estimate the linear and angular speeds of the vehicle with high accuracy as well as its ability to follow the real trajectory drove by the vehicle along long paths within a minimum error.

Synthetic Metals, 2007

The demonstration of organic thin-film field-effect transistors (OFETs) using a solution-processa... more The demonstration of organic thin-film field-effect transistors (OFETs) using a solution-processable form of the organometallic molecule copper tetrabenzoporphyrin (CuTBP) is reported. A soluble precursor was spun-cast into an amorphous, insulating thin-film, and thermally annealed at 165 • C for 30 min into a polycrystalline organic semiconductor. Absorbance spectroscopy displayed characteristics of porphyrin macrocycles. Microscopy reveals the formation of domains comprising aligned nanorod aggregates with dimensions of 55 nm wide, 300 nm long, and 100 nm tall on the gate insulator surface. OFETs demonstrated field-effect mobilities typically on the order of 0.1 cm 2 /V s, threshold voltages around 5 V, subthreshold slopes around 4 V/dec, and ON-/OFF-current ratios near 10 4 .

BioMed Research International, 2014

We analyzed embryo culture medium (CM) and recipient blood plasma using Fourier transform infrare... more We analyzed embryo culture medium (CM) and recipient blood plasma using Fourier transform infrared spectroscopy (FTIR) metabolomics to identify spectral models predictive of pregnancy outcome. Embryos collected on Day 6 from superovulated cows in 2 countries were individually cultured in synthetic oviduct fluid medium with BSA for 24 h before embryo transfer. Spent CM, blank controls, and plasma samples (Day 0 and Day 7) were evaluated using FTIR. The spectra obtained were analyzed. The discrimination capability of the classifiers was assessed for accuracy, sensitivity (pregnancy), specificity (nonpregnancy), and area under the ROC curve (AUC). Endpoints considered were Day 60 pregnancy and birth. High AUC was obtained for Day 60 pregnancy in CM within individual laboratories (FranceAUC=0.751±0.039, SpainAUC=0.718±0.024), while cumulative data decreased the AUC (AUC=0.604 ± 0.029). Predictions for CM at birth were lower than Day 60 pregnancy. Predictions with plasma at birth improve...

Symmetry, Integrability and Geometry: Methods and Applications, 2007

We describe the reduction procedure for a symplectic Lie algebroid by a Lie subalgebroid and a sy... more We describe the reduction procedure for a symplectic Lie algebroid by a Lie subalgebroid and a symmetry Lie group. Moreover, given an invariant Hamiltonian function we obtain the corresponding reduced Hamiltonian dynamics. Several examples illustrate the generality of the theory.

Small, 2010

An in vitro comparison of conducting-polymer nanotubes of poly(3,4-ethylenedioxythiophene) (PEDOT... more An in vitro comparison of conducting-polymer nanotubes of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) and to their film counterparts is reported. Impedance, chargecapacity density (CCD), tendency towards delamination, and neurite outgrowth are compared. For the same deposition charge density, PPy films and nanotubes grow relatively faster vertically, while PEDOT films and nanotubes grow more laterally. For the same deposition charge density (1.44 C cm-2), PPy nanotubes and PEDOT nanotubes have lower impedance (19.5 ± 2.1 kΩ for PPy nanotubes and 2.5 ± 1.4 kΩ for PEDOT nanotubes at 1 kHz) and higher CCD (184 ± 5.3 mC cm-2 for PPy nanotubes and 392 ± 6.2 mC cm-2 for PEDOT nanotubes) compared to their film counterparts. However, PEDOT nanotubes decrease the impedance of neural-electrode sites by about two orders of magnitude (bare iridium 468.8 ± 13.3 kΩ at 1 kHz) and increase capacity of charge density by about three orders of magnitude (bare iridium 0.1 ± 0.5 mC cm-2). During cyclic voltammetry measurements, both PPy and PEDOT nanotubes remain adherent on the surface of the silicon dioxide while PPy and PEDOT films delaminate. In experiments of primary neurons with conducting-polymer nanotubes, cultured dorsal root ganglion explants remain more intact and exhibit longer neurites (1400 ± 95 μm for PPy nanotubes and 2100 ± 150 μm for PEDOT nanotubes) than their film counterparts. These findings suggest that conducting-polymer nanotubes may improve the long-term function of neural microelectrodes.

New England Journal of Medicine, 1996

Background. Clinical trials of antiretroviral drugs can take years to complete because the outcom... more Background. Clinical trials of antiretroviral drugs can take years to complete because the outcomes measured are progression to the acquired immunodeficiency syndrome (AIDS) or death. Trials could be accelerated by the use of end points such as changes in CD4 ϩ lymphocyte counts and plasma levels of human immunodeficiency virus type 1 (HIV-1) RNA and b 2-microglobulin, but there is uncertainty about whether these surrogate measures are valid predictors of disease progression. Methods. We analyzed data from the Veterans Affairs Cooperative Study on AIDS, which compared immediate with deferred zidovudine therapy. Patients' plasma levels of HIV-1 RNA and b 2-microglobulin were measured in stored plasma. Results. Among the 129 patients in the immediatetreatment group, 34 had disease that progressed to AIDS, as compared with 57 of the 141 patients in the deferredtreatment group (P ϭ 0.03). Progression to AIDS correlated strongly with base-line CD4 ϩ lymphocyte counts (P ϭ 0.001) and plasma levels of HIV-1 RNA (P Ͻ 0.001), but not with base-line levels of b 2-microglobulin (P ϭ 0.14). A decrease of at least 75 percent in the plasma level of HIV-1 RNA over the first six months of zidovudine therapy accounted for 59 percent of the benefit of treatment, defined as the absence of progression to AIDS (95 percent confidence interval, 13 to 112 percent). Plasma b 2-microglobulin levels and CD4 ϩ lymphocyte counts explained less of the effect of treatment. A 75 percent decrease in the plasma HIV-1 RNA level plus a 10 percent increase in the CD4 ϩ lymphocyte count could explain 79 percent of the treatment effect (95 percent confidence interval, 27 to 145 percent). Conclusions. Treatment-induced changes in the plasma HIV-1 RNA level and the CD4 ϩ lymphocyte count, taken together, are valid predictors of the clinical progression of HIV-related disease and can be used to assess the efficacy of zidovudine and possibly other antiretroviral drugs as well.

The Journal of Organic Chemistry, 2012

A full account of the development of the basemediated intramolecular Diels−Alder cycloadditions o... more A full account of the development of the basemediated intramolecular Diels−Alder cycloadditions of tryptamine-derived Zincke aldehydes is described. This important complexity-generating transformation provides the tetracyclic core of many indole monoterpene alkaloids in only three steps from commercially available starting materials and played a key role in short syntheses of norfluorocurarine (five steps), dehydrodesacetylretuline (six steps), valparicine (seven steps), and strychnine (six steps). Reasonable mechanistic possibilities for this reaction, a surprisingly facile dimerization of the products, and an unexpected cycloreversion to regenerate Zincke aldehydes under specific conditions are also discussed.

Journal of Investigative Dermatology, 2012

The Journal of Immunology, 2007

Vaccination of nonautoimmune prone mice with syngeneic dendritic cells (DC) readily induces anti-... more Vaccination of nonautoimmune prone mice with syngeneic dendritic cells (DC) readily induces anti-DNA autoantibodies but does not trigger systemic disease. We observed that anti-DNA autoantibody generation absolutely required αβ T cells and that γδ T cells also contributed to the response, but that regulatory T cells restrained autoantibody production. Although both NZB/W F1 mice and DC vaccinated C57/BL6 mice produced autoantibodies against dsDNA, vaccinated mice had higher levels of Abs against H1 histone and lower levels of antinucleosome Abs than NZB/W F1 mice. Despite a 100-fold increase in IL-12 and Th1 skewing to a foreign Ag, OVA, synergistic TLR activation of DC in vitro failed to augment anti-DNA Abs or promote class switching beyond that induced by LPS alone. TLR stimulation was not absolutely required for the initial loss of B cell tolerance because anti-DNA levels were similar when wild-type (WT) or MyD88-deficient DC were used for vaccination or WT and MyD88-deficient r...

Journal of Biomedical Materials Research Part A, 2007

Nerve injury, a significant cause of disability, may be treated more effectively using nerve guid... more Nerve injury, a significant cause of disability, may be treated more effectively using nerve guidance channels containing longitudinally aligned fibers. Aligned, electrospun nanofibers direct the neurite growth of immortalized neural stem cells, demonstrating potential for directing regenerating neurites. However, no study of neurite guidance on these fibers has yet been performed with primary neurons. Here, we examined neurites from dorsal root ganglia explants on electrospun poly-L-lactate nanofibers of high, intermediate, and random alignment. On aligned fibers, neurites grew radially outward from the ganglia and turned to follow the fibers upon contact. Neurite guidance was robust, with neurites never leaving the fibers to grow on the surrounding cover slip. To compare the alignment of neurites to that of the nanofiber substrates, Fourier methods were used to quantify the alignment. Neurite alignment, however striking, was inferior to fiber alignment on all but the randomly aligned fibers. Neurites on highly aligned substrates were 20 and 16% longer than neurites on random and intermediate fibers, respectively. Schwann cells on fibers assumed a very narrow morphology compared to those on the surrounding coverslip. The robust neurite guidance demonstrated here is a significant step toward the use of aligned, electrospun nanofibers for nerve regeneration.

Developmental Neurobiology, 2010

Neuritogenesis, neuronal polarity formation, and maturation of axons and dendrites are strongly i... more Neuritogenesis, neuronal polarity formation, and maturation of axons and dendrites are strongly influenced by both biochemical and topographical extracellular components. The aim of this study was to elucidate the effects of polylactic acid (PLLA) electrospun fiber topography on primary motor neuron development, since regeneration of motor axons is extremely limited in the central nervous system and could potentially benefit from the implementation of a synthetic scaffold to encourage re-growth. In this analysis, we found that both aligned and randomly-oriented submicron fibers significantly accelerated the processes of neuritogenesis and polarity formation of individual cultured motor neurons compared to flat polymer films and glass controls, likely due to restricted lamellipodia formation observed on fibers. In contrast, dendritic maturation and soma spreading were inhibited on fiber substrates after 2 days in vitro. This study is the first to examine the effects of electrospun fiber topography on motor neuron neuritogenesis and polarity formation. Aligned nanofibers were shown to affect the directionality and timing of motor neuron development, providing further evidence for the effective use of electrospun scaffolds in neural regeneration applications.

Chemistry of Materials, 2004

Nanostructured and nanorod-shaped three-dimensional In2O3 were deposited on stainless steel (SS) ... more Nanostructured and nanorod-shaped three-dimensional In2O3 were deposited on stainless steel (SS) by a novel potentiodynamic method at a high scan rate of 200 mV s-1. In2O3/SS electrodes were found to exhibit high specific capacitance, high power density, and long-term stability when used as active electrode materials for redox supercapacitors.

Biochemical Society Transactions, 2010

Steroid hormones control many aspects of animal physiology and behaviour. They are highly regulat... more Steroid hormones control many aspects of animal physiology and behaviour. They are highly regulated, among other mechanisms, by post-translational modifications of the transcription factors involved in their synthesis and response. In the present review, we will focus on the influence of SUMO (small ubiquitin-related modifier) and ubiquitin modifications on the function of transcription factors involved in adrenal cortex formation, steroidogenesis and the hormonal response.