Double layer capacitors in dye sensitized solar cells with large charge and energy storage capacity and controlled shape of output voltage signals.

The output signals in natural dyes-based solar cells (DSSC) can be either rising or decaying depending on the type of ions present in the system; these ions called added ions, are introduced by the additives: mordant and brighteners. The photon-dye interaction produces electrons, which eventually reach the electrode giving place to a superficially charged electrode in contact with an electrolyte where are the added ions. This combination produces, automatically, an electrical double-layer EDL structure which has important effects on the performance of the system: a) the added ions control, to a large extent, the initial shape of the output signal, giving rise to rising or decaying profiles; b) it is possible to store large amounts of energy and charge at high electric fields. This structure is found in many other systems that have a surface charged in contact with an electrolyte like piezoelectric materials in human body. This assertion was supported by determining important parameters such as the force between charged surfaces on both sides of the interface, the charge density, the energy density, and the capacitance. The Debye length has very small values then, many important quantities depend on this; it is possible to obtain large values for energy UDL ~ 3.6x105 Jm-3 and charge density ρDL ≈ 1.1x107 Cm-3 for double layer capacitors; these values are orders of magnitude larger than the corresponding values for electrostatic capacitors: Uelec ≈ 4.5x10-3 Jm-3 and ρelec ≈ 1.2 Cm-3. A non-linear model was also developed to fit unstable oscillations found in the output profiles produced by abrupt lighting.

Piezoelectric signals of HAp and collagen with different glucose concentrations: A method for diabetes detection.

Piezoelectric signals were obtained from samples based on hydroxyapatite (HAp) and collagen (C) containing different glucose (G) concentrations. HAp was obtained by coprecipitation using Ca2+ and HPO42- as precursor ions in solution. C and G were added at the beginning of the coprecipitation method during the HAp growth. The presence of glucose in HAp and collagen samples drastically reduces the voltage amplitudes and considerably increases the relaxation times of the piezoelectric signals. HAp and collagen are the main constituents of bone, muscle, etc., then, it is possible to use piezoelectric technology for local and early detection of high glucose concentrations: small pressures applied by electrodes or by actuators placed in appropriate places on the body to establish a background concentration and, from this, to determine regions of the body with high local glucose concentrations: weak signals and large relaxation times are associated with a diminishing in the sensitivity, and are indicative of the presence of regions of abnormally high glucose concentrations.

The Prevalence of the Risk of Sexual Dysfunction in the First and Third Trimesters of Pregnancy in a Sample of Spanish Women.

Sexuality is a central aspect for all human beings. Research into the prevalence of sexual dysfunction in pregnant Spanish women is scarce. The aim of this work is to examine the prevalence of risk of sexual dysfunctions in pregnant Spanish women and determine in which trimester the greatest difficulties in sexual response occur. The sample consisted of 180 pregnant Spanish women, with an average age of 32.03 years (SD = 4.93). The participants completed a questionnaire for socio-demographic data, as well as the female sexual function index, the state/trait depression inventory, and the dyadic adjustment scale. The results indicate that the percentage of women with a risk of sexual dysfunction was 65% in the first trimester and 81.11% in the third trimester. Likewise, the highest score on the depression questionnaire was in the third trimester, and the couple's relationship also improved in the third trimester. To improve women's sex lives during pregnancy, it is recommended to increase sexual education and information for both pregnant women and their partners.

Dynamic light scattering: A fast and reliable method to analyze bacterial growth during the lag phase.

A comparison between plate counting (PC) and dynamic light scattering (DLS) is reported. PC is the standard technique to determine bacterial population as a function of time; however, this method has drawbacks, such as the cumbersome preparation and handling of samples, as well as the long time required to obtain results. Alternative methods based on optical density are faster, but do not distinguish viable from non-viable cells. These inconveniences are overcome by using DLS. Two different bacteria strains were considered: Escherichia coli and Staphylococcus aureus. DLS was performed at two different illuminating conditions: continuous and intermittent. By the increment of particle size as a function of time, it was possible to observe cell division and the formation of aggregates containing very few bacteria. The scattered intensity profiles showed the lag phase and the transition to the exponential phase of growth, providing a quantity proportional to viable bacteria concentration. The results revealed a clear and linear correlation in both lag and exponential phase, between the Log10(colony-forming units/mL) from PC and the Log10 of the scattered intensity Is from DLS. These correlations provide a good support to use DLS as an alternative technique to determine bacterial population.

Synthesis and characterization of a HAp-based biomarker with controlled drug release for breast cancer.

A biocompatible hybrid porous polymer-ceramic material was synthesized to be used as a biomarker in the treatment of breast cancer. This device was equipped with the capacity to release medicaments locally in a controlled manner. The biomaterial was Hydroxyapatite(HAp)-based and had a controlled pore size and pore volume fraction. It was implemented externally using a sharp end and a pair of barbed rings placed opposite each other to prevent relative movement once implanted. The biomarker was impregnated with cis-diamine dichloride platinum (II) [Cl2-Pt-(NH3)2]; the rate of release was obtained using inductively coupled plasma atomic emission spectroscopy (ICP-AES), and release occurred over the course of three months. Different release profiles were obtained as a function of the pore volume fraction. The biomaterial was characterized using scanning electron microscopy (SEM) and Raman spectroscopy.

Determination of lead ion removal from a flowing electrolyte in the presence of a magnetic field using Raman spectroscopy.

PURPOSE: The authors report on the development of a new, noninvasive method to efficiently remove metal ions in aqueous solution flowing in a tube and to quantify the concentrations of those ions. Such a technique could be used to remove toxic ions in the interiors of arteries and veins in patients intoxicated by the ingestion of metal ions. METHODS: A magnetic field is applied to an aqueous electrolyte flowing in a specially designed rectangular cell in order to deflect the ion trajectories and concentrate them at one side of a cell. Once the ions are concentrated, they can be removed. Raman spectroscopy is used to promptly determine the concentration of the removed lead ions. RESULTS: It is possible to increase, on one side of the cell, the ion concentration by more than 80% with respect to the average concentration; the removed ions were taken from this high concentration region. This approach is a rapid, efficient, and noninvasive method for the removal of ions in aqueous solution. Raman spectroscopy was found to be a suitable technique to determine the amount of removed ions. CONCLUSIONS: The results indicate that the ion concentration can be increased more than 80% in a region where they can be removed. The increment in the ion concentration produced by the deflection due to the magnetic field, together with the use of Raman spectroscopy, allows for a rapid analysis of the removed ions without any previous preparation. The proposed method is a potentially useful method for metal ion separation of interest in the medical physics field.

[Locally administered ropivacaine vs. standard analgesia for laparoscopic cholecystectomy]. / Ropivacaína local contra analgesia estándar en colecistectomía laparoscópica.

BACKGROUND: It is unknown which analgesic modality gives better results after a laparoscopic cholecystectomy. The aim of this study was to compare the analgesic efficacy of ropivacaine for local use against that of intravenous dipyrone in laparoscopic cholecystectomy. METHODS: A non-inferiority randomized clinical trial. Fifty patients with laparoscopic cholecystectomy were included into two separate groups. INTERVENTION: 0.75 % ropivacaine infiltrated at the trocar insertion sites and in the gallbladder fossa compared with intravenous dipyrone. MEASUREMENTS: The primary outcome was pain, which was assessed using the visual analog scale during the first 24 hours. Secondary outcomes were the presence of adverse effects, and the need for analgesic rescue with tramadol. RESULTS: The visual analog scale average for pain at the conclusion of the surgery was 3.8 in the ropivacaine vs. 3.56 in the dipyrone groups, while at 6, 12 and 24 hours the values were 2.64, 1.92 and 1.28, respectively, for ropivacaine versus 2.6, 1.88 and 1.2, respectively, for dipyrone. No adverse effects were observed in either group, and the two groups exhibited similar needs for analgesic rescue with tramadol. CONCLUSIONS: Infiltration of 0.75 % ropivacaine at the trocar insertion sites and the gallbladder exhibits analgesia similar to IV dipyrone during the first 24 hours post-laparoscopic cholecystectomy without adverse effects.

Introducción: se desconoce qué modalidad analgésica brinda mejores resultados después de una colecistectomía laparoscópica. El objetivo de este estudio consistió en valuar la eficacia analgésica de la ropivacaína usada localmente contra la dipirona por vía intravenosa en colecistectomía laparoscópica. Métodos: ensayo clínico al azar, de no inferioridad, en 50 pacientes con colecistectomía laparoscópica para comparar el uso de ropivacaína al 0.75 % infiltrada en el lugar de inserción de los trócares y en la fosa vesicular frente a dipirona por vía intravenosa. El desenlace primario fue dolor evaluado mediante escala visual análoga (EVA) en las primeras 24 horas. Resultados: el promedio de las EVA de dolor al término de la cirugía fue de 3.8 frente a 3.56 en el grupo de ropivacaína o de dipirona, mientras que a las 6, 12 y 24 horas fueron 2.64 frente a 2.6, 1.92 frente a 1.88 y 1.28 frente a 1.2, respectivamente. No hubo efectos adversos en ningún grupo y la necesidad de rescates analgésicos con tramadol fue similar entre ambos grupos. Conclusiones: la ropivacaína al 0.75 % infiltrada en el lugar de inserción de los trócares y la fosa vesicular muestra una analgesia similar a la dipirona por vía intravenosa en las primeras 24 horas después de una colecistectomía laparoscópica, sin efectos adversos.

Escherichia coli viability determination using dynamic light scattering: a comparison with standard methods.

To determine the concentration of bacteria in a sample is important in the food industry, medicine and biotechnology. A disadvantage of the plate-counting method is that a microorganism colony could arise from one cell or from many cells. The other standard methodology, known as optical density determination, is based on the turbidity of a suspension and registers all bacteria, dead and alive. In this article, dynamic light scattering is proposed as a fast and reliable method to determine bacterial viability and, consequently, time evolution. Escherichia coli was selected because this microorganism is well known and easy to handle. A correlation between the data from these three techniques was obtained. We were able to calculate the growth rate, usually determined by plate counting or optical density measurement, using dynamic light scattering and to predict bacterial behavior. An analytical relationship between the colony forming units and the light scattered intensity was also deduced.

Spermatozoa from mice deficient in Niemann-Pick disease type C2 (NPC2) protein have defective cholesterol content and reduced in vitro fertilising ability.

The cholesterol content of the sperm membrane is regulated during both maturation in the epididymis and capacitation in the female tract, two processes required for the spermatozoa to acquire their fertilising ability. Because Niemann-Pick disease, type C2 (NPC2) protein is one of the most abundant components of the epididymal fluid and contains a functional cholesterol-binding site that can transfer cholesterol between membranes, it has been suggested for years that NPC2 could be involved in the regulation of cholesterol levels in spermatozoa during epididymal maturation. In the present study, western blot and immunohistochemistry analyses demonstrated significant levels of NPC2 in the mouse epididymal epithelium. Epididymal spermatozoa obtained from NPC2(-/-) mice were morphologically normal and had normal motility parameters, but had a reduced cholesterol content compared with that of wild-type (WT) spermatozoa, as determined by both biochemical and by flow cytometry analyses. These results suggest that NPC2 could be involved in regulating cholesterol levels in spermatozoa during epididymal maturation. To understand the relevance of epididymal NPC2 for sperm function, the ability of spermatozoa to undergo events influenced by epididymal maturation, such as capacitation and fertilisation, were compared between WT and NPC2(-/-) mice. Capacitated NPC2(-/-) spermatozoa exhibited defective tyrosine phosphorylation patterns and a reduced ability to fertilise cumulus-oocyte complexes compared with WT spermatozoa, supporting the relevance of mouse epididymal NPC2 for male fertility.

Alternativas de derivación de LCR en pacientes de alta complejidad. Revisión de la literatura a raíz del caso de un recién nacido con Hidrocefalia post hemorrágica / Alternatives CSF shunt in patients highly complex: review of the literature following the case of a newborn with post hemorrhagic hydrocephalus

La hemorragia intraventricular (HIV) es una causa importante de daño cerebral en los recién nacidos prematuros. Su impacto negativo en el resultado del desarrollo neurológico se relaciona no sólo a su impacto directo, sino que también a las lesiones asociadas, como la hidrocefalia posthemorrágica (HPH). En la mayoría de los casos, la hidrocefalia es causada por la alteración de la reabsorción del líquido cefalorraquídeo (LCR) debido a la inflamación de las vellosidades subaracnoideas por el contacto con la sangre. El drenaje ventricular se utiliza a menudo como un procedimiento temporal para manejo de la HPH y algunos pacientes tratados con drenaje ventricular no requieren una derivación permanente; de no ser así, las derivaciones más usadas en los prematuros incluyen la ventriculoperitoneal (DVP), seguida por las derivaciones ventriculosubgaleal y ventriculoatrial. Las derivativas se consideran el tratamiento definitivo para la HPH; pero puede asociarse a complicaciones, tales como la infección, obstrucción, rechazo y el drenaje insuficiente. Otra alternativa, es la derivación ventrículopleural. Sin embargo, esta alternativa de derivación se vincula a otras complicaciones específicas, principalmente el neumotórax y el derrame pleural. Se presenta el caso clínico de EAV, quien a raíz de un parto prematuro, complicado con Hemorragia intraventricular, desarrolló Hidrocefalia y un quiste de Fosa Posterior, debiendo intervenirse en 36 oportunidades, por múltiples complicaciones. Durante su evolución se instalaron catéteres en prácticamente todos los sitios posibles, lográndose finalmente la solución del problema. Se revisa la literatura

Ventricular haemorrhage is an important cause of neurologic damage in preterm babies. Its negative impact in the final neurologic damage is not just related with the direct impact, but also with associated lesions like posthaemorrhagic hydrocephalus (PHH). In most of cases, hydrocephalus is caused by impaired cerebrospinal fluid (CEF) resorption due to the inflammation of the Arachnoid granulations because of the contact with blood. Ventricular drainage system is often used as a temporal procedure for the management of the PHH in children who have not a good response to serials lumbar punctures. Some patients treated with ventricular drainage don't need a permanent derivation, but if they do the most used in preterm babies include ventriculoperitoneal derivation (VPD) followed by ventriculosubgaleal and ventriculoatrial derivation. Derivation is considered the definitive treatment for PHH, but it can be associated with some complications as infection, obstruction and insufficient drainage. Another option is ventriculopleural derivation but this alternative is related to other complications like pneumothorax and pleural effusion. The presentation is about the case of the newborn EAV, who after preterm birth, complicated with intraventricular haemorrhage, developed hydrocephalus and a posterior fossa cyst, requiring 36 surgical interventions because of multiple complications. During its evolution he needed catheters installations in almost every possible sites, finally getting the problem solved. The literature is reviewed

Scratch and abrasion properties of polyurethane-based micro- and nano-hybrid obturation materials.

Polyurethane-based micro- and nano-hybrid composites were produced with controlled porosity to be used as obturation materials. In addition to hydroxyapatite (HAp) micro-particles in the composites, two different ceramics particle types were also added: alumina micro-particles and silica nano-particles. Particles of different sizes provide the materials with improved mechanical properties: the use of micro- and nano-particles produces a better packing because the nano-particles fill the interstitial space left by the micro-particles, rendering an improvement in the mechanical properties. The silica and alumina particles provide the materials with appropriate abrasion and scratching properties, while the HAp provides the required bio-acceptance. The polymeric matrix was a mono-component solvent-free polyurethane. The porosity was selected by controlling the chemical reaction.

Stabilized Conversion Efficiency and Dye-Sensitized Solar Cells from Beta vulgaris Pigment.

Dye-Sensitized Solar Cells (DSSCs), based on TiO(2) and assembled using a dye from Beta vulgaris extract (BVE) with Tetraethylorthosilicate (TEOS), are reported. The dye BVE/TEOS increased its UV resistance, rendering an increase in the cell lifetime; the performance of these solar cells was compared to those prepared with BVE without TEOS. The efficiency η for the solar energy conversion was, for BVE and BVE/TEOS, of 0.89% ± 0.006% and 0.68% ± 0.006% with a current density Jsc of 2.71 ± 0.003 mA/cm2 and 2.08 ± 0.003 mA/cm2, respectively, using in both cases an irradiation of 100 mW/cm2 at 25 °C. The efficiency of the BVE solar cell dropped from 0.9 ± 0.006 to 0.85 ± 0.006 after 72 h of operation, whereas for the BVE/TEOS, the efficiency remained practically constant in the same period of time.

New dye-sensitized solar cells obtained from extracted bracts of Bougainvillea glabra and spectabilis betalain pigments by different purification processes.

The performance of a new dye-sensitized solar cell (DSSC) based in a natural dye extracted from the Bougainvillea spectabilis' bracts, is reported. The performance of this solar cell was compared with cells prepared using extract of the Bougainvillea glabra and mixture of both extracts; in both cases the pigments were betalains, obtained from Reddish-purple extract. These dyes were purified to different extents and used for the construction of solar cells that were electrically characterized. The materials were characterized using FTIR and UV-Vis. Solar cells were assembled using TiO(2) thin film on indium tin oxide (ITO)-coated glass; a mesoporous film was sensitized with the Bougainvillea extracts. The obtained solar energy conversion efficiency was of 0.48% with a current density J(SC) of 2.29 mA/cm(2) using an irradiation of 100 mW/cm(2) at 25 °C.

In vivo evaluation of implant-host tissue interaction using morphology-controlled hydroxyapatite-based biomaterials.

In medicine, micro-electro-mechanical systems (MEMS) perform several specific functions. The design of bio-packages for MEMS to be implanted into the human body has been an increasing challenge in the last years. Mechanical, chemical and thermal resistance, as well as excellent bonding to silicon surfaces, are needed. Furthermore, ideal bio-packages should minimize post-operative complications and be well accepted by the host. To reach this goal, two different morphology-controlled hydroxyapatite-based porous biomaterials were synthesized, implanted in rats and evaluated mechanically and histologically. The novel biomaterials were prepared at room temperature using synthetic hydroxyapatite micro-particles, silica nanoparticles and water-based resin and compared with a standard hydroxyapatite biomaterial. The morphology (porosity) was controlled to obtain interconnected pores with appropriated pore size and pore volume fraction. All biomaterials were implanted in rats at the dorsal area near the third thoracic vertebra. The rats were killed 2, 7 and 21 days after surgery. Histological analysis revealed that the implants were well accepted by the host and minimal local inflammation was observed. The acute inflammatory response disappeared 21 days after surgery for both novel biomaterials. Additionally, organic matter (collagen) was produced in the interior of the porous biomaterial, indicating that an incipient vascularization process was in progress after 21 days of implantation. Both new biomaterials showed high abrasion resistance, high Young modulus, the appropriate porosity to allow possible vascularization, and good bonding to silicon surfaces.

Grb2 is a negative modulator of the intrinsic Ras-GEF activity of hSos1.

hSos1 is a Ras guanine-nucleotide exchange factor. It was suggested that the carboxyl-terminal region of hSos1 down-regulates hSos1 functionality and that the intrinsic guanine-nucleotide exchange activity of this protein may be different before and after stimulation of tyrosine kinase receptors. Using different myristoylated hSos1 full-length and carboxyl-terminal truncated mutants, we show that Grb2 function accounts not only for recruitment of hSos1 to the plasma membrane but also for modulation of hSos1 activity. Our results demonstrate that the first two canonical Grb2 binding sites, inside the carboxyl-terminal region of hSos1, are responsible for this regulation. Following different approaches, such as displacement of Grb2 from the hSos1-Grb2 complex or depletion of Grb2 levels by small interfering RNA, we found that the full-length Grb2 proteins mediate negative regulation of the intrinsic Ras guanine-nucleotide exchange activity of hSos1.

The histone acetyltransferases CBP/p300 are degraded in NIH 3T3 cells by activation of Ras signalling pathway.

The CBP [CREB (cAMP-response-element-binding protein)-binding protein]/p300 acetyltransferases function as transcriptional co-activators and play critical roles in cell differentiation and proliferation. Accumulating evidence shows that alterations of the CBP/p300 protein levels are linked to human tumours. In the present study, we show that the levels of the CBP/p300 co-activators are decreased dramatically by continuous PDGF (platelet-derived growth factor) and Ras signalling pathway activation in NIH 3T3 fibroblasts. This effect occurs by reducing the expression levels of the CBP/p300 genes. In addition, CBP and p300 are degraded by the 26 S proteasome pathway leading to an overall decrease in the levels of the CBP/p300 proteins. Furthermore, we provide evidence that Mdm2 (murine double minute 2), in the presence of active H-Ras or N-Ras, induces CBP/p300 degradation in NIH 3T3 cells. These findings support a novel mechanism for modulating other signalling transduction pathways that require these common co-activators.

The P34G mutation reduces the transforming activity of K-Ras and N-Ras in NIH 3T3 cells but not of H-Ras.

Ras proteins (H-, N-, and K-Ras) operate as molecular switches in signal transduction cascades controlling cell proliferation, differentiation, or apoptosis. The interaction of Ras with its effectors is mediated by the effector-binding loop, but different data about Ras location to plasma membrane subdomains and new roles for some docking/scaffold proteins point to signaling specificities of the different Ras proteins. To investigate the molecular mechanisms for these specificities, we compared an effector loop mutation (P34G) of three Ras isoforms (H-, N-, and K-Ras4B) for their biological and biochemical properties. Although this mutation diminished the capacity of Ras proteins to activate the Raf/ERK and the phosphatidylinositol 3-kinase/AKT pathways, the H-Ras V12G34 mutant retained the ability to cause morphological transformation of NIH 3T3 fibroblasts, whereas both the N-Ras V12G34 and the K-Ras4B V12G34 mutants were defective in this biological activity. On the other hand, although both the N-Ras V12G34 and the K-Ras4B V12G34 mutants failed to promote activation of the Ral-GDS/Ral A/PLD and the Ras/Rac pathways, the H-Ras V12G34 mutant retained the ability to activate these signaling pathways. Interestingly, the P34G mutation reduced specifically the N-Ras and K-Ras4B in vitro binding affinity to Ral-GDS, but not in the case of H-Ras. Thus, independently of Ras location to membrane subdomains, there are marked differences among Ras proteins in the sensitivity to an identical mutation (P34G) affecting the highly conserved effector-binding loop.