Design of a new test chamber for evaluation of the toxicity of rubber infill.

A test chamber was projected and built (according to ISO 16000-9 Standard) to simulate atmospheric conditions experienced by rubber infill (when applied in synthetic turf pitches) and measure accurately the airborne emissions of pollutants such as dusts and volatile organic compounds (VOC), as well as pollutants present in leachates. It should be pointed out that standard ISO 16000-9 is only concerned with the determination of the emission of VOC from building products and furnishing (not specific of synthetic turf materials), whereas other standards are concerned with the emission of leachates only. This procedure is to be considered as a technical option to the lysimeter "global turf system evaluation" when the rubber infill alone is to be evaluated. The advantage of the proposed option considering this "test chamber" is its simplicity and economy. This test chamber is actually installed and being used for tests in LAIST.

On the need for quality assurance in superficial kilovoltage radiotherapy.

External auditing of beam output and energy qualities of four therapeutic X-ray machines were performed in three radiation oncology centres in northeastern Brazil. The output and half-value layers (HVLs) were determined using a parallel-plate ionisation chamber and high-purity aluminium foils, respectively. The obtained values of absorbed dose to water and energy qualities were compared with those obtained by the respective institutions. The impact on the prescribed dose was analysed by determining the half-value depth (D(1/2)). The beam outputs presented percent differences ranging from -13 to +25%. The ratio between the HVL in use by the institution and the measurements obtained in this study ranged from 0.75 to 2.33. Such deviations in HVL result in percent differences in dose at D(1/2) ranging from -52 to +8%. It was concluded that dosimetric quality audit programmes in radiation therapy should be expanded to include dermatological radiation therapy and such audits should include HVL verification.

Bio-nanotechnology and photodynamic therapy--state of the art review.

Photodynamic therapy (PDT) and bio-nanotechnology (NT) show striking similarities in clinical design and mechanistics. The PDT paradigm of photosensitizer application, light activation and singlet oxygen generation does in fact occur on the nanoscale level as does the resultant outcomes. NT has the ability to explain as well as modify each of the critical steps of PDT particularly photosensitizer design and delivery, light source miniaturization and optimization, location and intensity of the photodynamic reaction as well as offering a far greater insight into dosimetry and mechanisms of action. This review will explore the current and potential future interactions and modifications NT may have on PDT.

Determination of absorbed dose in water at the reference point d(r0, theta0) for an 192Ir HDR brachytherapy source using a Fricke system.

A ring-shaped Fricke device was developed to measure the absolute dose on the transverse bisector of a 192Ir high dose rate (HDR) source at 1 cm from its center in water, D(r0, theta0). It consists of a polymethylmethacrylate (PMMA) rod (axial axis) with a cylindrical cavity at its center to insert the 192Ir radioactive source. A ring cavity around the source with 1.5 mm thickness and 5 mm height is centered at 1 cm from the central axis of the source. This ring cavity is etched in a disk shaped base with 2.65 cm diameter and 0.90 cm thickness. The cavity has a wall around it 0.25 cm thick. This ring is filled with Fricke solution, sealed, and the whole assembly is immersed in water during irradiations. The device takes advantage of the cylindrical geometry to measure D(r0, theta0). Irradiations were performed with a Nucletron microselectron HDR unit loaded with an 192Ir Alpha Omega radioactive source. A Spectronic 1001 spectrophotometer was used to measure the optical absorbance using a 1 mL quartz cuvette with 1.00 cm light pathlength. The PENELOPE Monte Carlo code (MC) was utilized to simulate the Fricke device and the 192Ir Alpha Omega source in detail to calculate the perturbation introduced by the PMMA material. A NIST traceable calibrated well type ionization chamber was used to determine the air-kerma strength, and a published dose-rate constant was used to determine the dose rate at the reference point. The time to deliver 30.00 Gy to the reference point was calculated. This absorbed dose was then compared to the absorbed dose measured by the Fricke solution. Based on MC simulation, the PMMA of the Fricke device increases the D(r0, theta0) by 2.0%. Applying the corresponding correction factor, the D(r0, theta0) value assessed with the Fricke device agrees within 2.0% with the expected value with a total combined uncertainty of 3.43% (k=1). The Fricke device provides a promising method towards calibration of brachytherapy radiation sources in terms of D(r0, theta0) and audit HDR source calibrations.

Toward endobronchial Ir-192 high-dose-rate brachytherapy therapeutic optimization.

A number of patients with lung cancer receive either palliative or curative high-dose-rate (HDR) endobronchial brachytherapy. Up to a third of patients treated with endobronchial HDR die from hemoptysis. Rather than accept hemoptysis as an expected potential consequence of HDR, we have calculated the radial dose distribution for an Ir-192 HDR source, rigorously examined the dose and prescription points recommended by the American Brachytherapy Society (ABS), and performed a radiobiological-based analysis. The radial dose rate of a commercially available Ir-192 source was calculated with a Monte Carlo simulation. Based on the linear quadratic model, the estimated palliative, curative and blood vessel rupture radii from the center of an Ir-192 source were obtained for the ABS recommendations and a series of customized HDR prescriptions. The estimated radius at risk for blood vessel perforation for the ABS recommendations ranges from 7 to 9 mm. An optimized prescription may in some situations reduce this radius to 4 mm. The estimated blood perforation radius is generally smaller than the palliative radius. Optimized and individualized endobronchial HDR prescriptions are currently feasible based on our current understanding of tumor and normal tissue radiobiology. Individualized prescriptions could minimize complications such as fatal hemoptysis without sacrificing efficacy. Fiducial stents, HDR catheter centering or spacers and the use of CT imaging to better assess the relationship between the catheter and blood vessels promise to be useful strategies for increasing the therapeutic index of this treatment modality. Prospective trials employing treatment optimization algorithms are needed.

Quality assurance of HDR 192Ir sources using a Fricke dosimeter.

A prototype of a Fricke dosimetry system consisting of a 15 x 15 x 15 cm3 water phantom made of Plexiglas and a 11.3-ml Pyrex balloon fitted with a 0.2 cm thick Pyrex sleeve in its center was created to assess source strength and treatment planning algorithms for use in high dose rate (HDR) 192Ir afterloading units. In routine operation, the radioactive source is positioned at the end of a sleeve, which coincides with the center of the spherical balloon that is filled with Fricke solution, so that the solution is nearly isotropically irradiated. The Fricke system was calibrated in terms of source strength against a reference well-type ionization chamber, and in terms of radial dose by means of an existing algorithm from the HDR's treatment planning system. Because the system is based on the Fricke dosimeter itself, for a given type and model of 192Ir source, the system needs initial calibration but no recalibration. The results from measurements made over a 10 month period, including source decay and source substitutions, have shown the feasibility of using such a system for quality control (QC) of HDR afterloading equipment, including both the source activity and treatment planning parameters. The benefit of a large scale production and the use of this device for clinical HDR QC audits via mail are also discussed.

A generalização baseada nas relaçoes implicacionais em sujeitos submetidos a terapia fonológica / Generalization based on implicational relations in subjects treated with phonological therapy

BACKGROUND: Generalization based on implicational relations. AIM: To analyze generalization based on implicational relations in subjects with mild-moderate phonological disorder, who underwent therapy based on the Maximal Oppositions Model. METHOD: The initial phonological system of four subjects was analyzed, taking in consideration sounds that were not completely acquired and their changes in probes. A final phonological assessment was made. RESULTS: All subjects presented generalizations based on implicational relations and expanded their phonological systems. CONCLUSION: The Maximal Oppositions Model favored generalizations based on implicational relations.

Tema: a generalização baseada nas relações implicacionais. Objetivo: analisar a generalização baseada nas relações implicacionais de sujeitos com desvio fonológico médio-moderadosubmetidos ao Modelo de Oposições Máximas. Método: foram analisados os sistemas fonológicos iniciais de quatro sujeitos considerando-se os sons não adquiridos e suas mudanças nas sondagens e na avaliação fonológica final. Resultados: todos os sujeitosapresentaram generalizações baseadas nas relações implicacionais e expandiram seus sistemas fonológicos. Conclusão: o Modelo de Oposições Máximas proporcionou a ocorrência de generalizações baseadas em relações implicacionais.

(HP)Ge Measurement of spectra for diagnostic X-ray beams.

The X-ray spectra applied in diagnostic radiology to the energy range between 50 and 125 kVp, were experimentally determined using a high-purity germanium detector, (HP)Ge, coupled to a multichannel analyser. A simple stripping procedure was implemented, according to that described by Seelentag and Panzer, to correct the pulse height distribution and then to determine the photon spectra. The measurements were performed for those conditions where the X-ray beam is transmitted through Pb filters 0.2-0.7 mm thick. It was necessary to estimate the effective dose in the same way that it is done for radiology diagnosis room shielding projects. The spectra were also determined to the X-ray qualities recommended by the IEC for primary diagnostic X-ray and for X-ray beams attenuated by aluminium filters 2.5-42.5 mm thick. The spectra obtained were compared with data derived from the literature presenting good agreement.

Clinical PD/PDT in North America: An historical review.

The healing properties of light have been appreciated for thousands of years. However, the harnessing of light energy to create a rigorous and reliable means to diagnose and treat human disease is only a relatively recent phenomenon. Despite outstanding results from ancient history and subsequent reemergence and refinement of this knowledge over the last 100 years, it took again the hand of serendipity to open the modern age of Photodiagnosis and Photodynamic Therapy. Based on the prescience and perseverance of a handful, the under appreciated observations of tumor fluorescence and photodynamic action have been brought to a worldwide audience. This review highlights the development of clinical Photodiagnosis and Photodynamic Therapy, emphasizing the significant events and milestones taking place in North America.

A new optics-based gastroesophageal reflux probe.

This work was carried out with the purpose of developing a new method of gastroesophageal reflux (GOR) detection. It is based on the emission of a light beam to the inferior part of the oesophagus and on the detection and analysis of the corresponding reflected light intensity. The optical properties of the oesophageal lumen are then used to identify the GOR episodes, solving, in this way, the existing drawback of using pH probes that fail in the cases where GOR episodes are neutral or short duration acid. The necessary instrumentation for the application of this new technique, including the probe itself and its associated optics, was developed. The result is a low-cost portable instrument, based on the Microchip microcontroller PIC16C77, with enough flexibility to be used in other biomedical applications. This new simple apparatus only needs an adequate light source - diode laser - and an adequate photosensor - photodiode - to make the interface to the probe that guides the light to and from oesophagus. Our results show the capability of this new technique to make the identification of GOR episodes.

[Primary immunodeficiency secondary to ZAP-70 deficiency]. / Imunodeficiência primária por défice de ZAP-70.

The authors present the case of a child with recurrent infections since the age of 4 months, including bilateral pneumonia by Pneumocystis carinii and protracted varicella. Serum immunoglobulin values (when 10 months old), and B cell values were normal. There was persistent lymphocytic leucocytosis, near absence of CD8+ cells, and an increased CD4/CD8 ratio. The percentage of activated T cells and the expression of HLA class I were normal. Proliferation, activation and IL-2 synthesis studies in T cells showed a TCR/CD3-associated signal transduction deficit. ZAP-70 cDNA sequencing showed a mutation, and no ZAP-70 protein was detected in T cells. ZAP-70 deficiency is associated with a rare immune deficiency with absence of CD8+ T cells as well as a functional deficiency in T cells. Seven months after bone marrow transplantation the child is clinically well and immunologically recovered.

[My history of pediatrics]. / A minha história da pediatria.

In an attempt to discern the paradigms underlying our medical practice (more specifically paediatrics) over the last 30 years, it was found that these are rather similar to the ones prevailing at the beginning of this period--all wrong-doings were attributed to outside forces which had to be neutralized; the obsession to standardise the internal milieu; the compulsion to always do something, little attention being paid to collateral effects; the ends justifying the means and the charm of technology.

Absence of lysozyme (muramidase) in the intestinal Paneth cells of newborn infants with necrotising enterocolitis.

AIM: To determine immunocytochemically whether preterm and newborn infants with necrotising enterocolitis (NEC) show differences in numbers of lysozyme positive Paneth cells compared with normal controls, and to relate the findings to the possibility that lysozyme deficiency may facilitate the bacterial infections thought to be associated with this condition. METHODS: Tissues from 10 infants with NEC and from 11 matched controls were sectioned and stained immunocytochemically for lysozyme. Differences in the numbers of Paneth cells and degree of lysozyme positivity in the tissues were assessed. RESULTS: Tissues from NEC patients showed no, or very few, lysozyme positive Paneth cells, whereas controls showed strong positive staining. CONCLUSIONS: A deficiency or developmental defect in Paneth cells, resulting in an absence of lysozyme, may render the intestine more susceptible to bacterial infection, allowing organisms to adhere and translocate across the mucosa. Such enhancement of infection may contribute to the pathogenesis of NEC.

Neurobrucellosis in children.

UNLABELLED: Neurobrucellosis is an uncommon disease in children. The authors present two cases of brucellar meningo-encephalitis. Headache and vomiting were the main complaints and one child had also some behavioural disturbance as well as papilloedema and sixth cranial nerve palsy. The clinical diagnosis was suggested by epidemiological data in both cases. Blood and CSF cultures confirmed brucellar aetiology in one of the cases and positive serum and CSF specific antibodies in both. Clinical course was favourable after treatment with doxycycline, rifampicin and streptomycin. No relapse occurred and there were no sequelae. CONCLUSION: Neurobrucellosis should be considered in the differential diagnosis of neurobehavioural disturbance of children living in areas where brucellosis is endemic.

Efeitos tardios da malnutricao precoce / Slow effects of the precocious mal-nutrition

A malnutricao do lactente esta frequentemente associada aum subsequente atraso de crescimento e de desenvolvimento, mas e dificil distinguir o papel da malnutricao do ambiente onde aquela habitualmente ocorre. Conhecem-se mal os efeitos dum episodio agudo de malnutricao nos primeiros meses de vida, seguido duma recuperacao nutritiva rapida e definitiva, antes de ter terminado o surto de crescimento cerebral. Desanove lactentes marasmaticos no primeiro semestre de vida, por causas medicas e sem problemas perinatais ou sociais, foramseguidos prospectivamente depois duma recuperacao rapida. Nao mais apresentaram malnutricao e as relacoes intrafamiliares foram sempre boas. Na idade escolar, apercentagem ex-malnutridos com baixa estatura era superior a dos seus companheiros; os ex-malnutridos eram mais baixos que os seus irmaos. Verificou-se uma correlacao negativa significativa entre os valores da estatura ( por cento p50) na idade escolar e a duracao do atraso estatural (E