Wide-angle filters based on nanoresonators for the visible spectrum.

We present a design for a highly efficient and omnidirectional color-selective filter for the visible spectrum, based on a Fabry-Perot metal-dielectric-metal nanoresonator. The filter can have the same color transmitted in a range of incident angles from 0° up to 60° for TM polarization. The dielectrics used for each color filter are carefully chosen so that the angle-insensitive resonance conditions are satisfied while transmission values from 44.3% to 78.36% are achieved. We calculated the dielectric thickness for each filter and analyzed the optimal Ag thickness for maximum transmission. The proposed filters have a simple multilayer structure and do not require complex lithographic fabrication processes.

Contamination of public transports by Staphylococcus aureus and its carriage by biomedical students: point-prevalence, related risk factors and molecular characterization of methicillin-resistant strains.

OBJECTIVES: To analyse the contamination of public transports by Staphylococcus aureus and assess its carriage by biomedical students, focussing on the point-prevalence, related risk factors and molecular characterization of methicillin-resistant strains. STUDY DESIGN: Cross-sectional survey. METHODS: Methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolated from handrails of buses (n = 112) and trains (n = 79) circulating in Porto and from nasal swabs of local university students (n = 475) were quantified, characterized by molecular typing methods and related to possible risk factors. RESULTS: The MRSA prevalence in buses (16.1%) was not significantly different from trains (8.9%). There was also no identifiable association between the counts of MSSA and MRSA in buses and trains and the number of travellers in each sampling day, specific routes (including those passing by main hospitals) or other risk factors. Of the students, 37.1% carried S. aureus, and having a part-time job or smoking were found to be risk factors for carriage. EMRSA-15 (ST22-SCCmecIVh) was the prevalent MRSA clonal lineage, found not only in the buses (n = 14) and trains (n = 2) but also in the single MRSA-carrier among the students. The characteristics of the community-associated Southwest Pacific MRSA clone were found in a single ST30-IVa isolate, which may suggest a recent SCCmec acquisition by an MSSA background in the community. CONCLUSIONS: The spread of EMRSA-15, a common hospital-associated lineage, among different public transports and as a nasal coloniser is of concern and warrants adequate public health control measures.

Control of predators in industrial scale microalgae cultures with Pulsed Electric Fields.

This work describes the utilization of Pulsed Electric Fields to control the protozoan contamination of a microalgae culture, in an industrial 2.7 m(3) microalgae photobioreactor. The contaminated culture was treated with Pulsed Electric Fields, PEF, for 6h with an average of 900 V/cm, 65 µs pulses of 50 Hz. Working with recirculation, all the culture was uniformly exposed to the PEF throughout the assay. The development of the microalgae and protozoan populations was followed and the results showed that PEF is effective on the selective elimination of protozoa from microalgae cultures, inflicting on the protozoa growth halt, death or cell rupture, without affecting microalgae productivity. Specifically, the results show a reduction of the active protozoan population of 87% after 6h treatment and 100% after few days of normal cultivation regime. At the same time, microalgae growth rate remained unaffected.

Morfometria de Anastrepha fraterculus (Wied) (Diptera: Tephritidae) relacionada a hospedeiros nativos, Myrtaceae / Morphometry of Anastrepha fraterculus (Wied) (Diptera: Tephritidae) related to native Myrtaceae hosts

A mosca-das-frutas, Anastrepha fraterculus, tem, como principais hospedeiros primários, frutos de Myrtaceae. O tamanho do inseto pode ser indicador de aptidão e fecundidade, sendo os estudos morfométricos utilizados para auxiliar nestas identificações. Este trabalho objetivou verificar a associação entre peso dos frutos, pupários e tamanho das asas das moscas-das-frutas que se desenvolveram em diferentes mirtáceas. Foram amostrados frutos de araçazeiro-amarelo, araçazeiro-vermelho, goiabeira e goiabeira-serrana em cinco árvores de cada espécie. Os frutos foram pesados e os pupários oriundos destes pesados e individualizados. Registrou-se o número, sexo e área total da asa direita das moscas. Comparou-se o peso médio dos frutos, dos pupários e o tamanho de asas. O peso médio dos pupários foi maior em goiaba e araçá-vermelho. A maior área média de asa foi registrada nos indivíduos emergidos de goiabas e a menor, nos de araçá-amarelo. O peso dos frutos e dos pupários em araçá-amarelo, vermelho e goiaba-serrana não apresentaram associação significativa. Nas goiabeiras, a correlação entre o peso dos frutos e o dos pupários foi negativa. O peso dos frutos e a área da asa das moscas provenientes das espécies de mirtáceas não evidenciaram correlação. Os resultados indicam que a mosca é capaz de desenvolver-se de forma semelhante nas espécies de mirtáceas amostradas.

The fruit-fly Anastrepha fraterculus uses the myrtacean fruits as its main primary hosts. The insect size might be an indicator of aptitude and fecundity, and morphometric studies are used to help in those identifications. This study aimed to verify the association among fruit weight, puparial weight and wing size of fruit-flies that developed in different myrtacean species. Yellow strawberry guava, cattle guava, guava and feijoa fruits were sampled from 5 trees of each species. The fruits were weighed, and the puparia originated from them were also weighed and individualized. The number, gender and total right-wing area of the flies were registered. Mean fruit and puparial weights and wing sizes were compared. Mean puparial weight was higher in guava and cattle guava. The largest mean wing area was recorded for individuals from guavas; the smallest, for those from yellow strawberry guava. The fruit and puparial weights did not present a significant association in yellow strawberry guava, cattle guava and feijoa. In guavas, the correlation between fruit and puparial weights was negative. The fruit weight and wing area in all myrtacean species did not show any correlation. These results indicate the fly is able to develop similarly in all sampled myrtacean species.

Chronic propranolol treatment causes desensitization of the steroidogenic response in testicular interstitial cells but does not alter protein kinase C.

We investigated effects of chronic propranolol treatment on the secretory response of rat testicular interstitial cells (testosterone secretion) to subsequent in vitro stimulation with activators of protein kinase-C (PK-C) (L-propranolol, phorbol 12, 13-dibutyrate (PDBu), LHRH) or activators of protein kinase A (PK-A), (hCG or dibutyryl cAMP (dbcAMP)). We determined [3H]PDBu binding and PK-C activity in these cells. Treatment of rats with propranolol (Inderal 500 mg/L of water for 5 weeks) reduced by 48%, 50% and 29% the L-propranolol-, LHRH- or PDBu-induced testosterone secretion, respectively, when compared to cells from controls. This desensitization in testosterone secretion in vitro was also present when the testicular interstitial cells were stimulated with hCG or dbcAMP (secretion decreased by 65%/57%, respectively, when compared to cells from control rats). Challenging the cells originated from rats that received propranolol chronically with the addition in vitro of propranolol resulted in an additional reduction of the hCG/dbcAMP-stimulated testosterone secretion. Chronic propranolol-induced desensitization was not associated with a loss in [3H]PDBu binding or a decrease in PK-C activity. Chronic propranolol-induced desensitization can be uncoupled from down-regulation of protein kinase C. The effector responsible for the desensitization could be distal to the protein kinase C and protein kinase A.

[Primary amoebic meningoencephalitis: a case report]. / Meningoencefalitis amebiana primaria: comunicación de un caso.

INTRODUCTION: Infections of the central nervous system by free-living amoeba are a rare phenomenon around the world. They present as a necrotising haemorrhagic acute meningoencephalitis, with a fatality rate close to 100% or as granulomatous amoebic encephalitis with a chronic progression. CASE REPORT: We describe a fatal case of primary amoebic meningoencephalitis produced by Naegleria fowleri in an 8-year-old child, with a history of immersion in a freshwater reservoir 52 hours before death. CONCLUSION: Laboratory studies carried out before death did not enable a diagnosis to be reached while the patient was alive. Diagnosis was made in the course of the post-mortem examination, where the presence of amoeba trophozoites was identified.

Meningoencefalitis amebiana primaria: comunicación de un caso / Primary amoebic meningoencephalitis: a case report

Introducción. Las infecciones del sistema nervioso central producida por amebas de vida libre constituyen un fenómeno raro mundialmente. Ésta se presenta como una meningoencefalitis aguda hemorrágica necrotizante, con una letalidad cercana al 100 por ciento, o como una encefalitis granulomatosa amebiana de evolución crónica. Caso clínico. Se comunica un caso letal de meningoencefalitis amebiana primaria producida por Naegleria fowleri en un niño de 8 años, con el antecedente de inmersión en un embalse de agua dulce 52 horas antes de la muerte. Conclusión. Los estudios de laboratorio realizados antes del fallecimiento no permitieron el diagnóstico en vida del paciente. El diagnóstico se realizó en el estudio necrópsico, donde se identificó la presencia de trofozoítos de amebas (AU)

Introduction. Infections of the central nervous system by free-living amoeba are a rare phenomenon around the world. They present as a necrotising haemorrhagic acute meningoencephalitis, with a fatality rate close to 100% or as granulomatous amoebic encephalitis with a chronic progression. Case report. We describe a fatal case of primary amoebic meningoencephalitis produced by Naegleria fowleri in an 8-year-old child, with a history of immersion in a freshwater reservoir 52 hours before death. Conclusion. Laboratory studies carried out before death did not enable a diagnosis to be reached while the patient was alive. Diagnosis was made in the course of the post-mortem examination, where the presence of amoeba trophozoites was identified (AU)

Gliosarcoma.Presentación de cinco casos y revisión de la bibliografía / Gliosarcoma. Presentation of five cases and review of the literature

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[Primary diffuse leptomeningeal gliomatosis. Presentation of one case]. / Gliomatosis leptomeníngea difusa primaria: presentación de un caso.

A twenty-four-year-old woman presented with asthenia, anorexia and weight los associated with headache, neck ache, lumbo-sacral pain, flaccid quadriparous, bilaterally diminished vision and sphincter disorders. On computerized axial tomography of the skull, only slight signs of ventricular dilatation were seen. Cytochemical study of the cerebro-spinal fluid showed a marked increase in protein and there was a raised erythrocyte sedimentation rate. The patient was treated with steroids in view of the possibility of vasculitis or a demyelinating disorder. However the disease worsened and she died four months after onset of the disorder. Neuro-pathological study showed tumour infiltration of the leptomeninges of the base of both cerebral hemispheres, cerebellum and spinal medulla. The optic nerves, chiasma and spinal nerve roots were also infiltrated with neoplastic cells. No intraparenchymatous tumour was found. The neuropathological findings were compatible with primary diffuse leptomeningeal gliomatosis.

HST far-ultraviolet imaging of Jupiter during the impacts of comet Shoemaker-Levy 9.

Hubble Space Telescope far-ultraviolet images of Jupiter during the Shoemaker-Levy 9 impacts show the impact regions darkening over the 2 to 3 hours after the impact, becoming darker and more extended than at longer wavelengths, which indicates that ultraviolet-absorbing gases or aerosols are more extended, more absorbing, and at higher altitudes than the absorbers of visible light. Transient auroral emissions were observed near the magnetic conjugate point of the K impact site just after that impact. The global auroral activity was fainter than average during the impacts, and a variable auroral emission feature was observed inside the southern auroral oval preceding the impacts of fragments Q1 and Q2.

Isolation of clones on chromosome 7 that contain recognition sites for rare-cutting enzymes by oligonucleotide hybridization.

Five G/C-containing oligonucleotides that include the recognition sequences of rare-cutting restriction enzymes have been used to isolate almost 100 different genomic segments from chromosome 7 that contain recognition sites for those enzymes. Hybridization and washing at 27 degrees C allow the use of 8-bp radiolabeled oligonucleotides to detect specific G/C-containing sequences in less than 1 ng of cloned DNA. This method was used to isolate 9 positive clones from 138 previously isolated single-copy probes from a flow-sorted chromosome 7 library. The specificity of the method was confirmed by showing that clones that gave positive hybridization signals also contained the corresponding restriction site. The oligonucleotides were also used to analyze approximately 12,000 kb of genomic sequence from a newly constructed chromosome 7 cosmid library that yielded 88 positive cosmids from 350 analyzed. The average distances between binding sites ranged from 200 to 690 kb and was independent of the number of CpG residues present in the oligonucleotide. Confirmation that clones containing restriction sites for these rare-cutting enzymes are located near genes was obtained by hybridization to RNA and cross-species DNA blots.