UV and Visible Light Activated TiO2 Photocatalysis of 6-Hydroxymethyluracil, a Model Compound for the Potent Cyanotoxin Cylindrospermopsin

TiO2 photocatalyses of 6-hydroxymethyl uracil (6-HOMU) a model compound for the potent cyanotoxin, cylindrospermopsin (CYN), were carried out employing visible and UV irradiation using different non-metal doped TiO2 materials, nitrogen and fluorine-TiO2 (NF-TiO2), phosphorus and fluorine-TiO2 (PF-TiO2) and sulfur-TiO2 (S-TiO2). The model compound was readily degraded under UV TiO2 photocatalysis with pseudo-first-order rate constants (k) of 2.1, 1.0, and 0.44 h−1 for NF-TiO2, PF-TiO2 and S-TiO2, respectively. Under visible light activated (VLA), NF-TiO2 was the most active photocatalyst, PF-TiO2 was marginally active and S-TiO2 inactive. VLA NF-TiO2 was effective and increased the k with increasing pH from 3 to 9. The presence of humic acid (HA), Fe3+ and Cu2+ can enhance the degradation. However, at 20 ppm HA significant inhibition was observed, likely due to shadowing of the catalyst, quenching of ROS or blocking active sites of TiO2. We probed the roles of different reactive oxygen species (ROS) using specific scavengers and the results indicate that O2− plays an important role in VLA TiO2 photocatalysis. Our results demonstrate that NF-TiO2 photocatalysis is effective under UV and visible irradiation and over a range of water qualities. VLA NF-TiO2 photocatalysis is an attractive alternative technology for the CYN contaminated water treatment

High prevalence of scrapie in a dairy goat herd: tissue distribution of disease-associated PrP and effect of PRNP genotype and age

Following a severe outbreak of clinical scrapie in 2006–2007, a large dairy goat herd was culled and 200 animals were selected for post-mortem examinations in order to ascertain the prevalence of infection, the effect of age, breed and PRNP genotype on the susceptibility to scrapie, the tissue distribution of diseaseassociated PrP (PrP$^{\rm d}$), and the comparative efficiency of different diagnostic methods. As determined by immunohistochemical (IHC) examinations with Bar224 PrP antibody, the prevalence of preclinical infection was very high (72/200; 36.0%), with most infected animals being positive for PrP$^{\rm d}$ in lymphoreticular system (LRS) tissues (68/72; 94.4%) compared to those that were positive in brain samples (38/72; 52.8%). The retropharyngeal lymph node and the palatine tonsil showed the highest frequency of PrP$^{\rm d}$ accumulation (87.3% and 84.5%, respectively), while the recto-anal mucosa-associated lymphoid tissue (RAMALT) was positive in only 30 (41.7%) of the infected goats. However, the efficiency of rectal and palatine tonsil biopsies taken shortly before necropsy was similar. The probability of brain and RAMALT being positive directly correlated with the spread of PrP$^{\rm d}$ within the LRS. The prevalence of infection was influenced by PRNP genetics at codon 142 and by the age of the goats: methionine carriers older than 60 months showed a much lower prevalence of infection (12/78; 15.4%) than those younger than 60 months (20/42; 47.6%); these last showed prevalence values similar to isoleucine homozygotes of any age (40/80; 50.0%). Two of seven goats with definite signs of scrapie were negative for PrP$^{\rm d}$ in brain but positive in LRS tissues, and one goat showed biochemical and IHC features of PrP$^{\rm d}$ different from all other infected goats. The results of this study have implications for surveillance and control policies for scrapie in goats

Influence of maternal physical exercise on fetal and maternal heart rate responses

This study aims to determine if regular maternal physical exercise leads to measurable adaptations of the fetal autonomic nervous system (fANS) tested by fetal heart rate recovery time. A randomized controlled trial enrolled 131 pregnant women into two study groups, Exercise Group (EG) and Control Group (CG). All participants signed an informed consent, study was approved by the local Clinical Research Ethics Committee. Data was analyzed on 81 participants.EG participants (n = 43) received a supervised physical exercise program (PEP) three times a week from 10–12 to 36–40 weeks gestation. CG participants (n = 38) did not receive any supervised PEP. All women were tested between 34–36 weeks gestation using two walking tests of three minutes each at 40% and 60% maternal heart rate reserve. Resting fetal heart rate (FHR), FHR post-maternal exercise, and fetal recovery time (FRT) in minutes/seconds (m/s) were recorded. Resting FHR was similar between groups 140.88 ± 9 EG vs 141.95 ± 7.35 CG (p > .05). Difference in resting to post-maternal exercise FHR was statistically significant in fetuses from the CG (p .05). FRT was different between groups after both tests: 40% test: 2m15s ± 3m19s EG vs 7m6s ± 5m28s CG (p .05), except for maternal recovery time after 40% test (p < .05). Influence of maternal exercise in FHR response still remains unclear. Further research is needed to elicit a former conclusion on the effects of maternal exercise on fANS. Overall, exercise during pregnancy is safe and not harmful for the cardiovascular system of the fetus

MeV measurements of gamma-ray bursts by CGRO-COMPTEL

Since the launch of the Compton Gamma-Ray Observatory in April 1991, the imaging COMPTEL telescope has accumulated positions and 0.75–30 MeV spectra of more than thirty gamma-ray bursts within its ∼π sr field of view. In an ongoing collaboration with BACODINE/GCN, COMPTEL positions are relayed to a global network of multiwavelength observers in near real time (∼10 minutes). Here we summarize the MeV properties, and present spatial, spectral, and temporal data for the latest of these events, GRB 970807. In concurrence with earlier SMM and current BATSE, OSSE, and EGRET measurements, COMPTEL data add to the accumulating evidence that GRB spectra do seem to have a characteristic shape: a peak (inE2F(E) ) around several hundred keV; and a power law above (spectral index 1.5–3.5) extending beyond the COMPTEL energy range

Modeling pion and proton total cross-sections at LHC

To settle the question whether the growth with energy is universal for different hadronic total cross-sections, we present results from theoretical models for pion-proton, proton-proton and proton-antiproton total cross-sections. We show that present and planned experiments at LHC can differentiate between different models, all of which are consistent with presently available (lower energy) data. This study is also relevant for the analysis of those very high energy cosmic ray data which require reliable pion-proton total cross-sections as seeds. A preliminary study of the total pion-pion cross-sections is also made.Comment: 18 pages, 5 figures, submitted to Physics Letters

An all-sky search algorithm for continuous gravitational waves from spinning neutron stars in binary systems

Rapidly spinning neutron stars with non-axisymmetric mass distributions are expected to generate quasi-monochromatic continuous gravitational waves. While many searches for unknown, isolated spinning neutron stars have been carried out, there have been no previous searches for unknown sources in binary systems. Since current search methods for unknown, isolated neutron stars are already computationally limited, expanding the parameter space searched to include binary systems is a formidable challenge. We present a new hierarchical binary search method called TwoSpect, which exploits the periodic orbital modulations of the continuous waves by searching for patterns in doubly Fourier-transformed data. We will describe the TwoSpect search pipeline, including its mitigation of detector noise variations and corrections for Doppler frequency modulation caused by changing detector velocity. Tests on Gaussian noise and on a set of simulated signals will be presented.Comment: 22 pages, 10 figures, 1 table, Submitted to Classical and Quantum Gravit

Exploring alternative symmetry breaking mechanisms at the LHC with 7, 8 and 10 TeV total energy

In view of the annnouncement that in 2012 the LHC will run at 8 TeV, we study the possibility of detecting signals of alternative mechanisms of ElectroWeak Symmetry Breaking, described phenomenologically by unitarized models, at energies lower than 14 TeV. A complete calculation with six fermions in the final state is performed using the PHANTOM event generator. Our results indicate that at 8 TeV some of the scenarios with TeV scale resonances are likely to be identified while models with no resonances or with very heavy ones will be inaccessible, unless the available luminosity will be much higher than expected

Bosonic Quartic Couplings at LHC

We analyze the potential of the CERN Large Hadron Collider (LHC) to study anomalous quartic vector-boson interactions Z Z gamma gamma, Z Z Z gamma, W+ W- gamma gamma, and W+ W- Z gamma through the weak boson fusion processes q q -> q q gamma gamma and q q -> q q gamma Z(-> l+ l-) with l = electron or muon. After a careful study of the backgrounds and how to extract them from the data, we show that the process p p -> j j gamma l+ l- is potentially the most sensitive to deviations from the Standard Model, improving the sensitivity to anomalous couplings by up to a factor 10^4 (10^2) with respect to the present direct (indirect) limits.Comment: 18 pages, 2 figures, revised versio

Programa estándar de control de calidad para un sistema híbrido de tomografía por emisión de positrones-tomografía computarizada (PET-CT) utilizado en la Fundación Valle del Lili.

La utilización de Tomógrafos de última generación, como es el caso de los PET-CT, requiere el desarrollo de un programa de Control de Calidad que garantice la más precisa y exacta ejecución del tratamiento radiante usado para el diagnóstico de patologías. Este programa es dependiente del equipamiento, personal y software disponible para ello. Los métodos más usados emplean maniquís que simulan anatomías del cuerpo humano y hacen trabajo conjunto entre protocolos internacionales y nacionales, con los empleados por los fabricantes de Tomógrafos que se adecuan a las necesidades del servicio para el cual el Tomógrafo funciona. Basándose en los resultados obtenidos, se desarrolló un protocolo de control de calidad que abarca las pruebas rutinarias, su periodicidad y rangos de aceptación necesarias para la puesta en marcha de las técnicas que pueden desarrollarse en el tomógrafo híbrido por emisión de positrones BIOGRAPH mCT X-3R de SIEMENS® adquirido recientemente en la Fundación Valle del Lili (FVL), las acciones correctivas y preventivas para detectar y corregir posibles fallas y el proceder en caso de detección de desviaciones superiores a los rangos de precisión y exactitud aceptados. Con el fin de minimizar los errores en la planificación y administración de las dosis al paciente, mejorando así la calidad de la imagen diagnóstica con la dosis de radiación más razonablemente baja posible, consistente con el uso clínico del equipo empleado y la información requerida del estudio diagnóstico. El protocolo desarrollado en la FVL se ajusta a las recomendaciones de los estándares Quality Assurance for PET and PET-CT system del IAEA (2009), PET phantom instructions for evaluation for PET imagen quality del ACR (2010), Accreditation Program for CT del ACR (2002) y el estándar Español de Control de Calidad en radiodiagnóstico (2010), que junto con tres (3) maniquís (de agua de SIEMENS®, de agua de GE® y de Ge-68 de SIEMENS®)