A longitudinal analysis of sex differences in bone mineral accrual in healthy 8-19-year-old boys and girls

Background: Although early in life there is little discernible difference in bone mass between boys and girls, at puberty sex differences are observed. It is uncertain if these differences represent differences in bone mass or just differences in anthropometric dimensions. Aim: The study aimed to identify whether sex independently affects bone mineral content (BMC) accrual in growing boys and girls. Three sites are investigated: total body (TB), femoral neck (FN) and lumbar spine (LS). Subjects and methods: 85 boys and 67 girls were assessed annually for seven consecutive years. BMC was assessed by dual energy X-ray absorptiometry (DXA). Biological age was defined as years from age at peak height velocity (PHV). Data were analysed using a hierarchical (random effects) modelling approach. Results: When biological age, body size and body composition were controlled, boys had statistically significantly higher TB and FN BMC at all maturity levels (p < 0.05). No independent sex differences were found at the LS (p > 0.05). Conclusion: Although a statistical significant sex effect is observed, it is less than the error of the measurement, and thus sex difference are debatable. In general, sex difference are explained by anthropometric difference

Are Ichthyosporea animals or fungi? Bayesian phylogenetic analysis of elongation factor 1α of Ichthyophonus irregularis

Ichthyosporea is a recently recognized group of morphologically simple eukaryotes, many of which cause disease in aquatic organisms. Ribosomal RNA sequence analyses place Ichthyosporea near the divergence of the animal and fungal lineages, but do not allow resolution of its exact phylogenetic position. Some of the best evidence for a specific grouping of animals and fungi (Opisthokonta) has come from elongation factor 1alpha, not only phylogenetic analysis of sequences but also the presence or absence of short insertions and deletions. We sequenced the EF-1alpha gene from the ichthyosporean parasite Ichthyophonus irregularis and determined its phylogenetic position using neighbor-joining, parsimony and Bayesian methods. We also sequenced EF-1alpha genes from four chytrids to provide broader representation within fungi. Sequence analyses and the presence of a characteristic 12 amino acid insertion strongly indicate that I. irregularis is a member of Opisthokonta, but do not resolve whether I. irregularis is a specific relative of animals or of fungi. However, the EF-1alpha of I. irregularis exhibits a two amino acid deletion heretofore reported only among fungi. (C) 2003 Elsevier Science (USA). All rights reserved.

Model-based analysis of anaerobic acetate uptake by a mixed culture of polyphosphate-accumulating and glycogen-accumulating organisms

An increasing number of studies shows that the glycogen-accumulating organisms (GAOs) can survive and may indeed proliferate under the alternating anaerobic/aerobic conditions found in EBPR systems, thus forming a strong competitor of the polyphosphate-accumulating organisms (PAOs). Understanding their behaviors in a mixed PAO and GAO culture under various operational conditions is essential for developing operating strategies that disadvantage the growth of this group of unwanted organisms. A model-based data analysis method is developed in this paper for the study of the anaerobic PAO and GAO activities in a mixed PAO and GAO culture. The method primarily makes use of the hydrogen ion production rate and the carbon dioxide transfer rate resulting from the acetate uptake processes by PAOs and GAOs, measured with a recently developed titration and off-gas analysis (TOGA) sensor. The method is demonstrated using the data from a laboratory-scale sequencing batch reactor (SBR) operated under alternating anaerobic and aerobic conditions. The data analysis using the proposed method strongly indicates a coexistence of PAOs and GAOs in the system, which was independently confirmed by fluorescent in situ hybridization (FISH) measurement. The model-based analysis also allowed the identification of the respective acetate uptake rates by PAOs and GAOs, along with a number of kinetic and stoichiometric parameters involved in the PAO and GAO models. The excellent fit between the model predictions and the experimental data not involved in parameter identification shows that the parameter values found are reliable and accurate. It also demonstrates that the current anaerobic PAO and GAO models are able to accurately characterize the PAO/GAO mixed culture obtained in this study. This is of major importance as no pure culture of either PAOs or GAOs has been reported to date, and hence the current PAO and GAO models were developed for the interpretation of experimental results of mixed cultures. The proposed method is readily applicable for detailed investigations of the competition between PAOs and GAOs in enriched cultures. However, the fermentation of organic substrates carried out by ordinary heterotrophs needs to be accounted for when the method is applied to the study of PAO and GAO competition in full-scale sludges. (C) 2003 Wiley Periodicals, Inc.

An approach to verifying and debugging simulation models governed by ordinary differential equations: Part 2. Residuals analysis and a case study

In Part 1 of this paper a methodology for back-to-back testing of simulation software was described. Residuals with error-dependent geometric properties were generated. A set of potential coding errors was enumerated, along with a corresponding set of feature matrices, which describe the geometric properties imposed on the residuals by each of the errors. In this part of the paper, an algorithm is developed to isolate the coding errors present by analysing the residuals. A set of errors is isolated when the subspace spanned by their combined feature matrices corresponds to that of the residuals. Individual feature matrices are compared to the residuals and classified as 'definite', 'possible' or 'impossible'. The status of 'possible' errors is resolved using a dynamic subset testing algorithm. To demonstrate and validate the testing methodology presented in Part 1 and the isolation algorithm presented in Part 2, a case study is presented using a model for biological wastewater treatment. Both single and simultaneous errors that are deliberately introduced into the simulation code are correctly detected and isolated. Copyright (C) 2003 John Wiley Sons, Ltd.

Nitrifying microbial community analysis of nitrite accumulating biofilm reactor by fluorescence in situ hybridization

Biological nitrogen removal via nitrite pathway in wastewater treatment is very important especially in the cost of aeration and as an electron donor for denitrification. Wastewater nitrification and nitrite accumulations were carried out in a biofilm reactor. The biofilm reactor showed almost complete nitrification and most of the oxidized ammonium was present as nitrite at the ammonium load of 1.2 kg N/m3/d. Nitrite accumulation was achieved by the selective inhibition of nitrite oxidizers by free ammonia and oxygen limitation. Nitrite oxidation activity was recovered as soon as the inhibition factor was removed. Fluorescence in situ hybridization studies of the nitrite accumulating biofilm system have shown that genus Nitrosomonas which is specifically hybridized with probe NSM 156 was the dominant nitrifying bacteria while Nitrospira was less abundant than those of normal nitrification systems. Further FISH analysis showed that the combinations of Nitrosomonas and Nitrospira cells were identified as important populations of nitrifying bacteria in an autotrophic nitrifying biofilm system.

Osteoblast, fibroblast and in vivo biological response to poly(vinylidene fluoride) based composite materials

Electroactivematerials can be taken to advantage for the development of sensors and actuators as well as for novel tissue engineering strategies. Composites based on poly(vinylidenefluoride),PVDF,have been evaluated with respect to their biological response. Cell viability and proliferation were performed in vitro both with Mesenchymal Stem Cells differentiated to osteoblasts and Human Fibroblast Foreskin 1. In vivo tests were also performed using 6-week-old C57Bl/6 mice. It was concluded that zeolite and clay composites are biocompatible materials promoting cell response and not showing in vivo pro-inflammatory effects which renders both of them attractive for biological applications and tissue engineering, opening interesting perspectives to development of scaffolds from these composites. Ferrite and silver nanoparticle composites decrease osteoblast cell viability and carbon nanotubes decrease fibroblast viability. Further, carbon nanotube composites result in a significant increase in local vascularization accompanied an increase of inflammatory markers after implantation.

Genetic diversity in sugar apple (Annona squamosa L.) by using RAPD markers

Genetic diversity in a collection of 64 sugar apple accessions collected from different municipalities in northern Minas Gerais was assessed by RAPD analysis. Using 20 selected RAPD primers 167 fragments were generated, of which 48 were polymorphic (28.7%) producing an average of 2.4 polymorphic fragments per primer. Low percentage of polymorphism (< 29%) was observed by using the set of primers indicating low level of genetic variation among the 64 accessions evaluated. Genetic relationships were estimated using Jaccard's coefficient of similarity. Accessions from different municipalities clustered together indicating no correlation between molecular grouping and geographical origin. The dendrogram revealed five clusters. The first cluster grouped C19 and G29 accessions collected from the municipalities of Verdelândia and Monte Azul, respectively. The second cluster grouped G16 and B11 accessions collected from the municipalities of Monte Azul and Coração de Jesus, respectively. The remaining accessions were grouped in three clusters, with 8, 15 and 37 accessions, respectively. In summary, RAPD showed a low percentage of polymorphism in the germplasm collection.

Microscopic analysis of "prato", "mussarela" and "mineiro" cheese sold in street markets of the City of S. Paulo, Southeastern Brazil

INTRODUCTION: Cheese should be produced from ingredients of good quality and processed under hygienic conditions. Further, cheese should be transported, stored and sold in an appropriate manner in order to avoid, among other things, the incorporation of extraneous materials (filth) of biological origin or otherwise, in contravention of the relevant food legislation. The aim of the study was to evaluate the hygienic conditions of "prato", "mussarela", and "mineiro" cheeses sold at the street food markets in the city of S. Paulo, Brazil. MATERIALS AND METHOD: Forty-seven samples of each of the three types of cheese were collected during the period from March, 1993 to February, 1994. The Latin square was used as a statistical model for sampling and random selection of the street markets from which to collect the cheese samples. The samples were analysed for the presence of extraneous matters outside for which purpose the samples were washed and filtered and inside, for which the methodology of enzymathic digestion of the sample with pancreatine, followed by filtering,was used. RESULTS AND CONCLUSION: Of the 141 samples analysed, 75.9% exhibited at least one sort of extraneous matters. For the "prato" and "mussarela" cheeses, the high number of contaminated samples was due mainly to extraneous matters present inside the cheese, whereas in the "mineiro" cheese, besides the internal filth, 100% of the samples had external filth.

Dissecting the role of CLASP1 in the mammalian development

A mitose é o evento celular, através do qual uma células transmite uma cópias do seu DNA às células filhas. Este processo é mediado pelo fuso mitótico, o qual consiste numa rede bipolar microtubulos. A dinâmica dos microtubulos é regulada por proteínas associadas a estes (MAPs – Microtubule-Associated Proteins), tais como as proteínas associadas às extremidades positivas dos microtubulos (+TIPs – Plus-ends Tracking proteins). As proteínas associadas às CLIPs (CLASPs – CLIP-associated proteins) pertencem a esta família e estão altamente conservadas nos eucariotas. Estas interagem com os microtubulos regulando o fuso mitótico, a segregação dos cromossomas e o comportamento dos microtubulos ao nível do cinetocoro. Assim, as CLASPs têm sido descritas como essenciais à manutenção da integridade genética durante a divisão celular. Um modelo animal knockout para o gene Clasp1 é uma ferramenta indispensável à descoberta do papel da CLASP1 a nível fisiológico. Nos animais knockout foi observado um fenótipo letal, no qual 100% dos recém-nascidos morreram poucos minutos após o nascimento, no decurso de falência respiratória. Após análise histopatológica, observamos que os pulmões dos animais knockout apresentam um atraso no desenvolvimento. Porém, a análise da expressão de marcadores de diferenciação celular, mostrou que os pneumócitos tipo I e II estão presente e diferenciados nos animais knockout aquando do seu nascimento. No entanto, um defeito primário a nível pulmonar ainda não pode ser excluído. Níveis elevados de glicogénio no parênquima alveolar dos animais knockout sugerem imaturidade pulmonar ou deficiente produção do líquido surfactante. Adicionalmente, ainda não está esclarecido de que forma pode este atraso explicar a letalidade observada nos recémnascidos knockout. Verificamos também que expressão de CLASP1 é transiente ao longo do desenvolvimento, sendo particularmente elevada no cérebro, o que pode explicar o seu papel já descrito na biologia dos neurónios. A CLASP1 é ubiquamente expressa em mamíferos adultos, o que sugere que esta proteína é também importante em tecidos diferenciados. Nesta fase, o significado biológico da CLASP1 em mamíferos ainda não foi descortinado. No entanto, nenhum animal knockout para Clasp1 foi capaz de sobreviver ex uterus, o que sugere um papel fundamental desta proteína na fase final do desenvolvimento dos mamíferos.

Chemical and biological studies from an Azorean macroalga: Ulva rigida

3rd Portuguese Meeting on Medicinal Chemistry and 1st Portuguese-Spanish-Brazilian Meeting on Medicinal Chemistry, Aveiro, 28-30 Novembro 2012.

Use of a-SiC:H Semiconductor-Based Transducer for Glucose Sensing through FRET Analysis

Glucose sensing is an issue with great interest in medical and biological applications. One possible approach to glucose detection takes advantage of measuring changes in fluorescence resonance energy transfer (FRET) between a fluorescent donor and an acceptor within a protein which undergoes glucose-induced changes in conformation. This demands the detection of fluorescent signals in the visible spectrum. In this paper we analyzed the emission spectrum obtained from fluorescent labels attached to a protein which changes its conformation in the presence of glucose using a commercial spectrofluorometer. Different glucose nanosensors were used to measure the output spectra with fluorescent signals located at the cyan and yellow bands of the spectrum. A new device is presented based on multilayered a-SiC:H heterostructures to detect identical transient visible signals. The transducer consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructure optimized for the detection of the fluorescence resonance energy transfer between fluorophores with excitation in the violet (400 nm) and emissions in the cyan (470 nm) and yellow (588 nm) range of the spectrum. Results show that the device photocurrent signal measured under reverse bias and using appropriate steady state optical bias, allows the separate detection of the cyan and yellow fluorescence signals presented.

Computational analysis of quinoxalines N,N-Dioxide and ITS Derivates

A quinoxalina e seus derivativos são uma importante classe de compostos heterocíclicos, onde os elementos N, S e O substituem átomos de carbono no anel. A fórmula molecular da quinoxalina é C8H6N2, formada por dois anéis aromáticos, benzeno e pirazina. É rara em estado natural, mas a sua síntese é de fácil execução. Modificações na estrutura da quinoxalina proporcionam uma grande variedade de compostos e actividades, tais como actividades antimicrobiana, antiparasitária, antidiabética, antiproliferativa, anti-inflamatória, anticancerígena, antiglaucoma, antidepressiva apresentando antagonismo do receptor AMPA. Estes compostos também são importantes no campo industrial devido, por exemplo, ao seu poder na inibição da corrosão do metal. A química computacional, ramo natural da química teórica é um método bem desenvolvido, utilizado para representar estruturas moleculares, simulando o seu comportamento com as equações da física quântica e clássica. Existe no mercado uma grande variedade de ferramentas informaticas utilizadas na química computacional, que permitem o cálculo de energias, geometrias, frequências vibracionais, estados de transição, vias de reação, estados excitados e uma variedade de propriedades baseadas em várias funções de onda não correlacionadas e correlacionadas. Nesta medida, a sua aplicação ao estudo das quinoxalinas é importante para a determinação das suas características químicas, permitindo uma análise mais completa, em menos tempo, e com menos custos.

Sulfadiazine-potentiometric sensors for flow and batch determinations of sulfadiazine in drugs and biological fluids

New PVC membrane electrodes for the determination of sulfadiazine (SDZ) are presented. The electrodes are fabricated with conventional and tubular configurations with a graphite-based electrical contact, and no internal reference solution. The selective membranes consist of bis(triphenylphosphoranilidene)ammonium·SDZ (electrode A), tetraoctylammonium bromide (electrode B), or iron(II)-phthalocyanine (FePC) (electrode C) electroactive materials dispersed in a PVC matrix of o-nitrophenyl octyl ether (o-NPOE) plasticizer. The sensors A, B, and C displayed linear responses over the concentration ranges 1.0*10-2 – 1.0*10–5, 1.0*10–2 – 7.5*10–6, and 3.2*10–2 – 7.0* 10–6 mol l–1 (detection limits of 1.09, 2.04 and 0.87 mg ml–1) with anionic slopes of –57.3 ± 0.1, –46.7 ± 0.5, and –65.1 ± 0.2 mV decade–1, respectively. No effect from pH was observed within 4.0 – 5.5, 4.8 – 10, and 4.5 – 8, respectively, and good selectivity was found. The sensors were applied to the analysis of pharmaceuticals and biological fluids in steady state and in flow conditions.

Comparison of inverse planning systems based on biological or physical factors: Pinnacle®, Corvus® and Monaco®

Radiotherapy (RT) is one of the most important approaches in the treatment of cancer and its performance can be improved in three different ways: through the optimization of the dose distribution, by the use of different irradiation techniques or through the study of radiobiological initiatives. The first is purely physical because is related to the physical dose distributiuon. The others are purely radiobiological because they increase the differential effect between the tumour and the health tissues. The Treatment Planning Systems (TPS) are used in RT to create dose distributions with the purpose to maximize the tumoral control and minimize the complications in the healthy tissues. The inverse planning uses dose optimization techniques that satisfy the criteria specified by the user, regarding the target and the organs at risk (OAR’s). The dose optimization is possible through the analysis of dose-volume histograms (DVH) and with the use of computed tomography, magnetic resonance and other digital image techniques.