Papers by David Araujo Diaz
Ordinary and Extraordinary Movement Behaviour of Small Resident Fish within a Mediterranean Marine Protected Area
PloS one, 2016
It is important to account for the movement behaviour of fishes when designing effective marine p... more It is important to account for the movement behaviour of fishes when designing effective marine protected areas (MPAs). Fish movements occur across different spatial and temporal scales and understanding the variety of movements is essential to make correct management decisions. This study describes in detail the movement patterns of an economically and commercially important species, Diplodus sargus, within a well-enforced Mediterranean MPA. We monitored horizontal and vertical movements of 41 adult individuals using passive acoustic telemetry for up to one year. We applied novel analysis and visualization techniques to get a comprehensive view of a wide range of movements. D. sargus individuals were highly territorial, moving within small home ranges (< 1 km2), inside which they displayed repetitive diel activity patterns. Extraordinary movements beyond the ordinary home range were observed under two specific conditions. First, during stormy events D. sargus presented a shelter...
Variantes metodológicas del ABP: el ABP 4x4
El Aprendizaje Basado En Problemas En La Ensenanza Universitaria 2008 Isbn 978 84 8371 778 3 Pags 55 74, 2008
Journal of the American Chemical Society, Aug 27, 2008
We describe the functionalization of single-wall carbon nanotubes (SWNTs) with 4-(2trimethylsilyl... more We describe the functionalization of single-wall carbon nanotubes (SWNTs) with 4-(2trimethylsilyl)ethynylaniline and the subsequent attachment of a zinc-phthalocyanine (ZnPc) derivative using the reliable Huisgen 1,3-dipolar cycloaddition. The motivation of this study was the preparation of a nanotubebased platform which allows the facile fabrication of more complex functional nanometer-scale structures, such as a SWNT-ZnPc hybrid. The nanotube derivatives described here were fully characterized by a combination of analytical techniques such as Raman, absorption and emission spectroscopy, atomic force and scanning electron microscopy (AFM and SEM), and thermogravimetric analysis (TGA). The SWNT-ZnPc nanoconjugate was also investigated with a series of steady-state and time-resolved spectroscopy experiments, and a photoinduced communication between the two photoactive components (i.e., SWNT and ZnPc) was identified. Such beneficial features lead to monochromatic internal photoconversion efficiencies of 17.3% when the SWNT-ZnPc hybrid material was tested as photoactive material in an ITO photoanode. Figure 9. Photoaction spectrum of SWNT-ZnPc 5 recorded with a bias of 0.6 V versus Ag/AgCl (0.1 M KCl).
Cobalt and Nickel Zero-Valent Nanoparticles
Http Dx Doi Org 10 1080 00288330 2005 9517324, Mar 29, 2010
One of the aims of Mediterranean marine protected areas (MPAs) is to increase populations of expl... more One of the aims of Mediterranean marine protected areas (MPAs) is to increase populations of exploited species, such as the European spiny lobster (Palinurus elephas), which is considered a key species for its commercial and ecological value. Monitoring of temporal patterns in abundance of early benthic stages of P. elephas indicated that predation may be higher inside the Medes Islands MPA relative to adjacent control sites. Tethering experiments were performed to test whether predation rates actually differed within and outside the MPA. Relative mortality of recently-settled juveniles inside the MPA was much higher than in control sites in adjacent non-protected areas. Treatments with and without shelter indicated that predation on recently-settled juvenile spiny lobsters was moderated by the availability of suitable shelter. The decline or absence of fish predators in the fished area may be the reason why juvenile lobsters outside the MPA experience lower predation than within the MPA.
Journal of Maritime Research, Aug 25, 2006
For years, and more and more insistently, globalization of economy and world trade is a common co... more For years, and more and more insistently, globalization of economy and world trade is a common concept which is in all communications media. Nevertheless, freight market and shipbuilding have been traditionally globalized markets. Does it mean that nothing has happened to these sectors? Of course, not. The globalization of the world trade has had and is having a crucial effect on shipping and shipbuilding, as it can be seen in the growing sizes of the vessels used in the transport.
There is growing evidence that processes other than predation have a critical role in determining... more There is growing evidence that processes other than predation have a critical role in determining sea urchin populations, causing unexpected responses to existing top-down control models. Although the biology and ecology of sea urchins have been widely studied, the long term dynamics of their populations are still poorly understood. This lack of knowledge is caused mainly by the scarcity of monitoring studies that are long and frequent enough to integrate interannual variability with low-frequency processes, which can be essential in determining the structure and dynamics of sea urchin populations. The aim of this study is to describe temporal variability in abundance and size-structure of the sea urchins Paracentrotus lividus and Arbacia lixula in rocky habitats in the northwestern Mediterranean. Two long-term monitoring series of data in two different marine protected areas are compared: Medes Islands Marine Reserve and the nearby unprotected area (measured annually from 1991 to 2012) are compared with the Port-Cros National Park (measured annually from 1983-1984 and 1994-2003). These series of data show how different processes, such as recruitment, predation or competition between both species, interact with other factors acting at different scales, such as a mass mortality episode that occurred in Port-Cros in 1982 or the effects of an exceptional storm in Medes Islands in 2008, or the increase of sea temperature during the study period.
First V-notching experience of a spiny lobster: V-notch recovery and impact on health and growth of Palinurus elephas
Journal of Crustacean Biology, 2014
ABSTRACT V-notching is a conservation technique to delay fishing mortality widely used in fisheri... more ABSTRACT V-notching is a conservation technique to delay fishing mortality widely used in fisheries of clawed lobsters. Here we present results of the first V-notching experience of a spiny lobster. The study was conducted on the European spiny lobster Palinurus elephas (Fabricius, 1787) with the aim of assessing: 1) V-notch effects on survival, incidence of shell disease and growth, and 2) the pattern of V-notch regrowth. Results of the 20-month-long tank experiment with 36 lobsters showed that V-notching had no impact on shell disease or growth. However, abnormally high summer temperatures in the experiment lowered survival of V-notched individuals relative to control specimens. Three dimensions of the V-notch mark (depth, width and area) were examined to assess V-notch regrowth, and depth is recommended for regulatory purposes. In this study, four moults, and almost two years, were necessary for V-notch depth to shrink by 50%, an amount that would turn legal a V-notched clawed lobster after one moult. We discuss the applicability of these results under conditions in the wild.
Personal software process (PSP) assistant
12th Asia-Pacific Software Engineering Conference (APSEC'05), 2005
... Raymund Sison David Diaz, Eliska Lam, Dennis Navarro, Jessica Navarro College of Computer Stu... more ... Raymund Sison David Diaz, Eliska Lam, Dennis Navarro, Jessica Navarro College of Computer Studies De La Salle University Manila, Philippines sisonr ... systems that support PSP in that it allows the automatic recording of compile defects of programs written in a variety of ...
Stabilization of Strong Quantum Confined Colloidal Bismuth Nanoparticles, One-Pot Synthesized at Room Conditions
The Journal of Physical Chemistry C, 2012
Wound Repair and Regeneration, 2012
Wound size reduction has been the standard benchmark for determination of efficacy for diabetic u... more Wound size reduction has been the standard benchmark for determination of efficacy for diabetic ulcer treatments but due to interclinician error and difficulty measuring irregular wound shapes, this method is unreliable with a positive predictive value of less than 60%. Diffuse near-infrared spectroscopy (DNIRS) uses 70-MHz modulated light in the diagnostic window (650-900 nm) noninvasively to quantify levels of oxyand deoxy-hemoglobin in the wound bed, which when measured over time, can show a trend toward or away from healing based on the changes in oxy-hemoglobin concentration from week to week. In this study, DNIRS was used to monitor 24 human diabetic foot ulcers longitudinally over the course of 20 weekly or biweekly measurement sessions. In just 4 weeks, the DNIRS system has an 82% positive predictive value (sensitivity of 0.9 and specificity of 0.86; p < 0.002). These data indicate that it could be possible to predict healing in 4 weeks using DNIRS, which can provide objective guidance toward the continuation of costly treatments. Discontinuing ineffective treatments after 4 weeks could have potentially saved over $12,600 per patient, based on the treatment regimen of patients in this study.
Novel Synthesis Pathway of ZnO Nanoparticles from the Spontaneous Hydrolysis of Zinc Carboxylate Salts
The Journal of Physical Chemistry B, 2003
A novel and easy synthesis pathway to synthesize small ZnO nanoparticles with a narrow size distr... more A novel and easy synthesis pathway to synthesize small ZnO nanoparticles with a narrow size distribution is reported. The synthesis implies the simple dissolution of a zinc carboxylate hydrated salt (cyclohexanebutyrate or acetate) in a polar basic aprotic solvent ...
Synthesis and Characterization of RuS 2 Nanostructures
The Journal of Physical Chemistry B, 2005
Small naked ruthenium sulfide nanoparticles (NPs) with narrow size distribution (2.5 +/- 0.4 nm o... more Small naked ruthenium sulfide nanoparticles (NPs) with narrow size distribution (2.5 +/- 0.4 nm of diameter) were synthesized in DMSO colloidal dispersions, under mild reaction conditions and using commercial RuCl3 as precursor. To test the chemical reactivity with soft and hard bases, fresh presynthesized RuS2 colloids were mixed with triethylamine (N(Et)3) and ammonium tetrathiomolybdate ((NH4)2MoS4) dimethyl sulfoxide solutions. Naked N(Et)3 and [MoS4](2-)-capped RuS2 nanoparticle colloids were characterized using UV-visible electronic absorption and emission spectroscopies and high-resolution transmission electron microscopy (HR-TEM). It has also been shown that capped RuS2-[MoS4]2- nanoparticles yield MoO3 crystalline matrix by means of HR-TEM experiments. The emission spectra of RuS2 and N(Et)3-RuS2 dispersions show that both nanosized materials have strong fluorescence. The existence of the ruthenium precursor species in solution was established by cyclic voltammetry. Moreover, naked RuS2 NPs were mixed with a chemical mixture with composition similar to gasoline (dibenzothiophene (Bz2S, 400 ppm), hexane, and toluene (55:45% v/v)). The reaction mixture consisted of two phases; in the polar phase, we found evidences of a strong interaction of Bz2S and toluene with the naked RuS2 NPs. We have also obtained self-organized thin films of capped N(Et)3- and RuS2-[MoS4]2- nanoparticles. In both cases, the shape and thickness of the resulting thin films were controlled by a dynamic vacuum procedure. The thin films have been characterized by atomic force microscopy, scanning electron microscopy, HR-TEM, energy dispersion spectroscopy, X-ray diffraction, and absorbance and fluorescence spectroscopies.
The Journal of Physical Chemistry B, 2008
In this report is discussed a novel, easy, and general synthesis method to prepare zerovalent iro... more In this report is discussed a novel, easy, and general synthesis method to prepare zerovalent iron (ZVI) and copper (ZV Cu) nanoparticles (NPs), from colloid dispersions in an environmental friendly organic solvent, ethylene glycol (EG). Conventional metallic salts are used as nanoparticle precursors; sodium borohydride (NaBH 4 ) is the reducing agent, and triethylamine (TEA) is used as the nanoparticle stabilizer. The chemical changes take place instantaneously under normal reaction conditions. Small iron (R-Fe 0 phase) and copper (fcc phase) NPs with average diameters of 10.2 ( 3.3 and 9.5 ( 2.5 nm, respectively, were obtained. In both cases, the experimental evidence reveals the absence of any metal oxide shell coating the particle surfaces, and their powders remain stable, under aerobic conditions at least for 3 weeks. ZVI NPs were characterized by X-RD, Mössbauer, and Raman spectroscopies and by EELS coupled to HR-TEM. Otherwise, copper NPs were characterized by X-RD, Z-contrast, and HR-TEM. This synthesis pathway is particularly suitable for large-scale and high-quality zerovalent metallic nanoparticle (ZV M NP) production due to its simple process and low cost.
Settlement and juvenile habitat of the European spiny lobster <i>Palinurus elephas</i> (Crustacea: Decapoda: Palinuridae) in the western Mediterranean Sea
Scientia Marina, 2001
Spiny lobsters (Crustacea: Decapoda: Palinuri-dae) are characteristic species of reef and rocky s... more Spiny lobsters (Crustacea: Decapoda: Palinuri-dae) are characteristic species of reef and rocky shores in tropical and temperate seas. From an eco-logical point of view, their size, abundance and loca-tion in the trophic web position them at a key point within the benthic ecosystem ...
Complexation and Solubility Behavior of Albendazole with Some Cyclodextrins
Pharmaceutical Development and Technology, 1998
The main purpose of this work was to study the albendazole-cyclodextrins complexation equilibrium... more The main purpose of this work was to study the albendazole-cyclodextrins complexation equilibrium and to propose a suitable excipient to improve the solubility behavior and dissolution rate of albendazole. The complexation of albendazole with four cyclodextrins, alpha-CD, beta-CD, gamma-CD, and hydroxypropylated (HP)-beta-CD, has been studied by using electronic absorption spectroscopy and molecular mechanics. The equilibrium was studied at pH 7.5 under various temperature conditions, and at pH 1.8 with HP-beta-CD at 298 K. The albendazole binding constant was the greatest for the HP-beta-CD. Both the un-ionized (Alb) and the ionized species (AlbH+) were shown to interact with HP-beta-CD. The studies at different temperatures suggest that the hydrophobic effect is the most important driving force in these systems. Moreover, the dissolution rate studies with beta- and HP-beta-CDs in the buffered aqueous solution at pH 7.5 have been accomplished and the dissolution rate was observed to increase with the cyclodextrin concentration. The solubility behavior was studied with the Higuchi and Connors method. The phase solubility and direct spectroscopy methods reveal a 1:1 inclusion complex in all of the studied cases. Molecular mechanics data show the most probable structure of the complexes.
Molecular Phylogenetics and Evolution, 2010
The European spiny lobster Palinurus elephas (Fabricius, 1787) is an ecologically and economicall... more The European spiny lobster Palinurus elephas (Fabricius, 1787) is an ecologically and economically important species inhabiting a wide geographic range that extends from the North-east Atlantic and Azores to the Eastern Mediterranean. We investigated the population structure and evolutionary history of this species by both mitochondrial and microsatellite markers. Ten population samples covering a large part of the species distribution range (three samples from the Atlantic Ocean and seven from the Mediterranean Sea) were analyzed for a portion of the mitochondrial control region and seven polymorphic microsatellite loci.
Molecular and Cellular Biology, 2013
Sos1 and Sos2 are ubiquitously expressed, universal Ras guanine nucleotide exchange factors (Ras-... more Sos1 and Sos2 are ubiquitously expressed, universal Ras guanine nucleotide exchange factors (Ras-GEFs) acting in multiple signal transduction pathways activated by upstream cellular kinases. The embryonic lethality of Sos1 null mutants has hampered ascertaining the specific in vivo contributions of Sos1 and Sos2 to processes controlling adult organism survival or development of hematopoietic and nonhematopoietic organs, tissues, and cell lineages. Here, we generated a tamoxifen-inducible Sos1-null mouse strain allowing analysis of the combined disruption of Sos1 and Sos2 (Sos1/2) during adulthood. Sos1/2 double-knockout (DKO) animals died precipitously, whereas individual Sos1 and Sos2 knockout (KO) mice were perfectly viable. A reduced percentage of total bone marrow precursors occurred in single-KO animals, but a dramatic depletion of B-cell progenitors was specifically detected in Sos1/2 DKO mice. We also confirmed a dominant role of Sos1 over Sos2 in early thymocyte maturation, with almost complete thymus disappearance and dramatically higher reduction of absolute thymocyte counts in Sos1/2 DKO animals. Absolute counts of mature B and T cells in spleen and peripheral blood were unchanged in single-KO mutants, while significantly reduced in Sos1/2 DKO mice. Our data demonstrate functional redundancy between Sos1 and Sos2 for homeostasis and survival of the full organism and for development and maturation of T and B lymphocytes.
Synthesis of ZnO Nanoparticles on a Clay Mineral Surface in Dimethyl Sulfoxide Medium
Langmuir, 2004
Nanocrystalline ZnO particles have been prepared with different methods using zinc cyclohexanebut... more Nanocrystalline ZnO particles have been prepared with different methods using zinc cyclohexanebutyrate as precursor in dimethyl sulfoxide (DMSO) medium via alkaline hydrolysis. A series of preparations were carried out in the presence of layered silicates (kaolinite and montmorillonite). It was revealed by different measurement techniques that the presence of the clay minerals has a stabilization influence on the size of the ZnO nanocrystals. UV-vis absorption spectra show a blue shift when the nanoparticles are prepared in the presence of the clay minerals. The average particle diameters calculated from the Brus equation ranged from 2.6 to 13.0 nm. The UV-vis spectra of the synthesized nanoparticles did not show any red shift after 2-3 days, demonstrating that stable ZnO nanocrystals are present in the dispersions. The presence of the ZnO nanoparticles was also proven by fluorescence measurements. A number of the nanoparticles are incorporated into the interlamellar space of the clays, and an intercalated structure is formed as proven by X-ray diffraction (XRD) measurements. The size of the nanoparticles in the interlamellar space is in the range of 1-2 nm according to the XRD patterns. Transmission electron microscopy and high-resolution transmission electron microscopy investigations were applied to determine directly the particle size and the size distribution of the nanoparticles.
Infections Mimicking Central Nervous System (CNS) Tumors
Journal of Neuropathology and Experimental Neurology, 1998
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Papers by David Araujo Diaz