bluuebunny/crossref_metadata_2025_split huggingface dataset:
A microscopic perspective of a microreactor
Authors: Carvalho F. , Paradiso P. , Fernandes P. 
Published: August 2013

The use of microreactors in (bio)chemical processes has been gaining relevance in the last decade. The low consumption of reagents, the possibility of continuous operation and the faster translation from lab- to production scale are some of the several advantages of these devices. The whole results in cost reductions in process development. Enzyme catalyzed reactions have proved to be an excellent alternative to the use of chemicals due to its ability to catalyze the most complex chemical processes under benign experimental and environmental conditions. In this way, enzymes may be crucial to the implementation of a much more sustainable chemical industry.The present work is within such scope, using as model system the immobilization of invertase in glass (silica) microchannels, for the production of fructose syrups through sucrose hydrolysis. The immobilization of the enzyme was achieved through treatment of the substrate with a sequence of coatings (Figure 1). Activation of the inner surface of the microchannels with 3-aminopropyltriethoxysilane (APTES) was followed by the introduction of a spacer, glutaraldehyde. Lastly the enzyme solution was introduced in the presence of sodium cyanoborohydride, in order to enhance the stability of the support-enzyme binding.The characterization of the coatings at each stage of the immobilization protocol was carried out to confirm the change of the microchannel surface. Such studies were performed using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) analysis (Figure 1).The results obtained, namely the shifts on the surface roughness corroborate that the several coatings were successfully applied and the enzyme immobilized. Moreover, the immobilization approach used proved to be highly effective, resulting on successful continuous use of the microreactor for a period of 30 days with roughly constant full conversion of a sucrose solution of 50g/l, at a flow rate of 7µl/minute (Figure 2).Future work will involve a more extensive characterization of the several coatings by Quartz Crystal Microbalance which will be decisive to achieve a better comprehension of the coating phenomena and hence optimize the immobilization process.The authors would like to thank Fundação para a Ciência e a Tecnologia, Portugal, for financial support through contracts under the program Ciência 2007 awarded to P. Fernandes, for the doctoral grant SFRH/BD/74818/2010 awarded to F. Carvalho and for the doctoral grant SFRH/BD/71990 /2010 awarded to Patrizia Paradiso.
Membranoproliferative glomerulonephritis with C3 and intramembranous dense deposits
Authors: Carvalho F. , Viana H. , Alves de Matos A.P. , Amoedo M. 
Published: August 2013

Membranoproliferative glomerulonephritis (MPGN) encompasses 7 to 10% of all biopsied glomerulonephritis. They are divided in: MPGN type I; MPGN type II and MPGN type III, being primary or secondary. MPGN type I are the most frequent, MPGN types II and III are very rare and difficult to diagnose without clinical and morphologic findings integration. MPGN type II or Dense Deposit Disease has a varied morphologic appearance with a few numbers of cases showing a membranoproliferative pattern by Light microscopy (LM). Electron microscopy (EM) is pivotal to confirm the diagnosis.We present a case of 35 years old man, with nephrotic proteinuria and mild renal insufficiency since 2 years. The only relevant clinical data is facial lipodystrophy. Complement 3 (C3) was low and C3 nephritic factor negative. There were not other relevant abnormalities. Renal biopsy was fixed in buffered formaldehyde 10% and performed for LM. The frozen fragment, prepared for observation by fluorescence microscopy - immunofluorescence (IMF) -, was prepared to be stained with florescent anti-serums, against immunoglobulines (IgG, IgA and IgM) and complement factors (C3, C4, and C1q). EM was later done on tissue formaldehyde fixed reprocessed from paraffin-embebbed for LM, because there was no tissue fragment fixed in glutaraldehyde.LM showed variable endocapillary hypercelullarity, with neutrophils infiltration. Capillary walls were thickened due to the deposition of elongate and ribbon-like deposits. Few double contours were visible (Figure 1a). IMF demonstrated the presence of C3 deposits in the capillary walls and mesangium (Figure 1b). EM confirmed the presence of an intramembranous dense deposit along basement membrane which was thickened (Figure 1c). LM and IMF findings favored the diagnosis of MPGN type II with C3 deposits and thickening of basement membrane. Nevertheless EM was essential to confirm intramembranous unequivocally dense deposits.MPGN type II is a rare glomerulonephritis mediated by complement deregulation. The integration of clinical and morphologic findings is essential to get a correct diagnosis. In this setting EM is highly distinctive and required for a definitive diagnosis.
Light microscopy studies on mice testis after the nutritional supplement chromium(III)-tris(picolinate)
Authors: Ferreira M. , Santos T.M. , Pereira M.L. 
Published: August 2013

Cr(III)-tris(picolinate), [Cr(pic)3], is a very common dietary supplement, recommended for humans, cattle and swine. Chromium is considered an essential trace element, when in oxidation state +3, with some of its compounds seeming to have a beneficial effect on blood sugar regulation mechanisms. However, the safety of the use of a particularly popular Cr(III) compound, ie [Cr(pic)3], remains debatable. Clastogenic, and mutagenic features have been reported by Stearns and co-workers, although surrounded by a controversial and contradictory multitude of publications on this subject. The present work aims to study the effects of [Cr(pic)3] on mice spermatogenesis.Cr(III)-tris(picolinate) was synthesized and characterized according to the literature. Its composition as a mononuclear complex was tested by ESI-MS and by X-ray powder diffraction followed by single-crystal simulation calculations.Male adult CDI mice from Harlan (Spain) were divided in groups and orally given 25 mg/kg and 50 mg/kg/body weigh/daily of [Cr(pic)3] for two weeks. Controls were also done. Behaviour and body weight were monitored throughout the experiments. After sacrifice, testis were collected, weighed, and fixed in Bouin´s solution. Organs were then prepared for histology using routine techniques. Animal experiments were conducted according to ethics procedures. Histological sections of control group evidenced normal regular features (Fig. 1a). However considerable damage was observed in both experimental groups in a dose dependent manner. In fact, seminiferous tubules showed degenerative changes within epithelium, namely vacuolation and sloughing of immature germ cells into the lumen in the group given the lowest dose (Fig.1 b,c). The high dosed group displayed more conspicuous injury within testis, namely strongly atrophic seminiferous tubules devoid of germs cells and strong vacuolation (Figs.1d-f).The results of this study have shown an increased risk of adverse events in mice receiving 50 mg/kg/body weight of [Cr(pic)3]. However, little potential for adverse reproductive and developmental effects namely on progeny was recently described for male mice fed a diet containing 200 mg/kg/day [Cr(pic)3]. In conclusion, concerns about using dietary supplements based on [Cr(pic)3] remain to be elucidated in future work.This work was financed by CICECO, Aveiro University, Portugal.
Histological staining approaches for high-quality imaging of Actinia equina and Anemonia sulcata anatomy
Authors: Gadelha J. , Morgado F. , Soares A.M.V.M. 
Published: August 2013

Sea anemones species identification of can be difficult, especially in the field. The taxonomic keys currently utilised are based mainly on histological differences and therefore require collection of whole animals. Furthermore, histological analysis of sea anemones requires considerable expertise and worldwide sea anemones histological descriptions are still limited. Here it is reported a detailed histological description of the internal structure of the two most conspicuous species in tidal pool communities in European shores, Actinia equina and Anemonia sulcata. This species description makes them excellent models for studying reproductive strategies that are instrumental in establishing and maintaining new populations. Therefore they are potential indicator species important both for micro and macro scale monitoring programs. The anatomy and histology of main organs of the studied sea anemones were described. The different colour morphs of the species were studied. Fine histological details of their muscular and digestive systems and appendages, down to the cellular level, were studied. They are two-germinal layer animals and possess radial symmetry in body form. Samples of the main organs of sea anemones including epidermis, tentacles, mesentery, gonads and digestive tract (mouth, stomodaeum and gastrovascular cavity) were processed for histological examination according to procedures described elsewhere [1,2]. The epithelia were composed of epithelio-muscular cells, in which many gland cells were distributed. Three types of cnidoblasts (nematooysts) were observed in the epithelioma of the tentacles, mesentery filament and stomodaeum. Cnidoblasts in different places have different functions. The gonads were of the follicular type and were composed of germ cells and nutritional cells. The investigation of the internal organization of invertebrate communities provides important information on the organism’s biology with special interest for the study of ecological processes to evaluate their reproductive modes in order to understand how they may reflect their dispersal strategies [1, 2]. Traits that influence reproduction in animal and plant species have been a central focus of evolutionary biology. Therefore, considering their basal position in evolution, the Anthozoa (Cnidaria) provide important models for further understanding processes affecting reproductive strategies in the eumetazoan (i.e., cnidarian-bilaterian) ancestor and in modern vertebrates.This work was supported by the Portuguese Foundation for the Science and Technology – Portugal and FEDER funds, through the Projects: PTDC/MAR/464729/2006 and FCT/CNPq (Brazil), Project 6818, Programme 19/ 004.
Histopathology of Zinc exposition in Actinia equina L. (Anthozoa, Actiniaria)
Authors: Gadelha J. , Ferreira C. , Soares A.M.V.M. , Pereira M.L. , Morgado F. 
Published: August 2013

Zinc is a trace metal that is regularly found at pollution sites, amongst other metals and pollutants, contributing to the toxicity of marine ecosystems. In this study zinc acute toxicity tests were conducted on the sea anemone Actinia equina. This sea anemone presents a wide geographic distribution on rocky shore marine habitats, is quite resistant to some degree of various forms of contaminants and plays an important ecological key role in the marine environments.After a period of acclimatising on a flow through system, organisms of the same average size were exposed to different concentrations of zinc solution during a period of 96 hours (0 µg/l, 10 µg/l, 50 µg/l, 100 µg/l, and 200µg/l). The histological processing of the specimens was performed using standard procedures, slightly modified due to the peculiar nature of the biological material.The general effects exhibited necrosis of tentacles, mesenterial filaments, and in the gastrodermal regions (Figures 1, 2 and 3). It were observed tentacular cysts, black particulate accumulations in the gastrodermis, hypertrophied cells in the lobes of the mesenteries filaments, and spirocyst and associated necrosis (Fig. 2-3). All anemones exhibited extensive areas of tissue necrosis, degeneration of the epidermis in various stages, with loss of mucous cells, vacuolation, necrosis and ptychocysts from the epidermis, necrosis of retractor muscles and ducts (Figures 2-3). Neoplasms of the gastrointestinal tract and gonads were observed in internal structures. In the former, modifications of the mesenteries such as intensive fragmentation, vacuolization and epithelial thinning and in the latter abnormal gonad development and necrosis were noted (Figures 2-3).The data suggests that Actinia equina may be adversely affected by acute exposures to high levels of zinc as seen during laboratory exposures of other invertebrates and is also probably sensitive to acute exposures to metal’s toxic sediments in the marine environment. The loss of mucous secretory cells and ptychocysts from the epidermis suggest that energy reserves for cell replenishment were adversely affected. Mucus production in benthic cnidarians is necessary to prevent burial by sedimentation and to protect against toxins or invading microorganisms. The serious effects on the gastrodermis integrity indicate that sea water in the coelenteron is no longer circulated. The observed modifications could be considered as a general cnidarians response to stress.Further investigations of bioaccumulation, physiology, and histopathology in this anemone and other anthozoans from polluted environments should prove to be valuable in pollution monitoring studies, as they have for other benthic invertebratesAcknowledgmentsThis work was supported by the Portuguese Foundation for the Science and Technology – Portugal and FEDER funds, through the Projects: PTDC/MAR/464729/2006 and FCT/CNPq (Brazil), Project 6818, Programme 19/ 004.
The importance of structural diversity of spores in the taxonomy of Aspergillus (section Nigri)
Authors: Simões M.F. , Santos C. , Lima N. 
Published: August 2013

Species of Aspergillus from section Nigri, also known as black aspergilli, are distributed worldwide and have been widely used for purposes of various types such as: biotechnological, industrial, medical, among others. They have been extensively studied for being the causing agents of biodeterioration of commodities and food.Within this section, new species have been recently described and among them Aspergillus ibericus and Aspergillus uvarum were both isolated from grapes. The polyphasic approach used in the analysis of these species, either by morphological techniques as well as by molecular methods, allowed not only their characterisation but also their consequent separation from all others in the section. Microbial taxonomy has the identification of species as one of its fundamental goals. Data such as: morphological characteristics description, physiological and biochemical properties, ecological roles, and societal risks or benefits, are key elements in any fungal identification process. But, this process is subjected to periodic changes due to frequent revisions of the taxonomic schemes, therefore becoming time consuming and more demanding and difficult, even for skilled specialists. Furthermore, each taxonomic group has specialised literature, terminology and characters. This takes place since identifications have difficulties of consensual naming, depending on the criteria used and the amount of information available when producing all data. It is increasingly becoming clear that, to better achieve a more accurate concept of species, microbial identification and authentication require a polyphasic approach to produce consistent, useful and quality data.Characterisation of morphologic and structural aspects of spores from Aspergillus strains, section Nigri, has been carried out using scanning electron microscopy (SEM) and intends to contribute to the associated data of the strains from this section.Colonies from 13 Aspergillus from section Nigri, from the Micoteca da Universidade do Minho (MUM), were grown at 25 ºC for 3 or 4 days in malt extract agar directly mounted in a sterilised SEM stub. The samples were covered with a mixture of gold and platinum (80/20%) and then examined in the SEM [NanoSEM - FEI NovaTM 200 (FEG/SEM); EDAX - Pegasus X4M (EDS/EBSD)]. A stereomicroscope (Leica MZ12.5) was used to have a clear image comparison of the size of the conidial head.Although the analysed strains presented dimensional, morphological and structural diversity, common or typical features could be inferred and related to each taxon like those represented in Fig 1.From the SEM analysis we were able to conclude that in the section Nigri of genus Aspergillus the spore wall ornamentation, and its size and shape continue to present themselves as important primary diagnostic traits for species differentiation.
Investigation of elemental distribution in cat femoral head by nuclear microprobe and SEM for Paget disease of bone studies
Authors: Santos C. , Fonseca M. , Corregidor V. , Alves L.C. , Luis H. , Capelão M. , Branco J.C. , Carvalho P.A. , Jesus A.P. 
Published: August 2013

Paget Disease of Bone is a disorder characterized by abnormal bone remodeling, associated with morphological and functional abnormalities of osteoclasts although its etiology remains unproven. Ion beam analysis (IBA) techniques may be useful to characterize the abnormal distribution and concentration of the major and trace elements that can be associated topagetic bone condition. In order to access the viability of this approach, healthy femoral head of cat has been investigated by Particle Induced X-Ray Emission (PIXE),Rutherford Backscattering Spectrometry (RBS) and Scanning Electron Microscopy (SEM).The bone section was irradiated, under vacuum conditions, with a 2.0 MeV alpha particle beam produced by the 2.5 MV Van de Graaff Accelerator of CTN/IST (Lisbon, Portugal). An Oxford Microbeams-type nuclear microprobe was used (OM150 triplet system), which allowed the proton beam to be focused on the bone section with a spatial resolution of 3x4 µm2 and a mean beam current of ~90pA. The X-rays generated by the bone were recorded using an 80 mm2 Link X-ray detector (with a 145 eV energy resolution), that is positioned at 135º to the beam direction. The backscattered particles were collected by a 200 mm2 silicon surface barrier radiation detector with a 15 keV energy resolution that is positioned at 40º to the beam direction in a cornell geometry. SEM observations have been carried out with backscattered electrons (BSE) using a JEOL JSM 7001F microscope equipped with an INCA Oxford Instruments EDS spectrometer for point analyses and X-ray mapping. Standard petrographic procedures have been employed to prepare the samples for SEM observation: the specimens were partly encapsulated in epoxy resin, ground with 800 and 1000-grit SiC paper, polished with 6 μm and 1 μm diamond suspensions and coated with carbon.A selected area of the sample has been scanned with the proton beam, allowing to generateelemental distribution maps for Ca and P (Figure 1). From X-line scans it was possible to extractline profiles of these elements. RBS and PIXE were used to determine the matrix and trace element composition in order to normalize the elemental concentrations. The results are shown in Table 1.Structural information on the Haversian Systems, includingbone lacunaeandosteocytes localization have been obtained by SEM (Figure 2).The combination of these techniques proved to be a viable approach for the Pagetic bone characterization and will be used to analyze the structure of trabecular and cortical bones as well as the distribution and morphology of the pagetic bone cells, which can contribute to clarify the differences between pagetic and healthy bone.V. Corregidor acknowledges the support from FCT-Ciência program. The work was also supported by FCT PEST-OE/CTM-UI0084/2011 grant.
Microscopy: A tool for quantitative pozzolanic activity in blended cements
Authors: Costa C. , Laginha I. , Carvalho P.A. 
Published: August 2013

The reuse of waste fluid catalytic cracking (FCC) catalyst, from oil-refinery industry, as a partial substitute of cement is a promising way of reducing the environmental impact of cement production and, therefore, contributes for industrial sustainability. On the other hand partial replacement of cement by oil-cracking catalysts up to 10-15% (w/w) results in improved mechanical properties as the waste catalyst tends to react with Ca(OH)2 - liberated upon cement hydration - and forms additional strength-providing reaction products. Nevertheless, the pozzolanic reaction mechanisms between cement and the waste FCC catalyst, which involve Ca migration from the cementitious matrix into the FCC particles is still not well understood.In the present study waste FCC catalyst has been incorporated in cement paste mortars with a 15:85 weight ratio. The microstructural evolution of the blended materials has been investigated by X-ray diffraction and scanning electron microscopy coupled with X-ray energy dispersive spectroscopy after curing times of 2, 7 and 28 days. Namely, the evolutions of the catalyst crystal structure and of the calcium content in the dispersed catalyst particles have been evaluated.The results show that the Ca/(Si,Al) ratio in the catalyst particles tends to increase during the cure. However, the inward migration does not occur in a continuous front but rather tends to follow high-diffusivity paths resulting in Ca depleted rims (Fig. 1). On the other hand the presence of heavy metals resulting from oil-cracking (such as La) remains essentially unaltered after a cure of 28 days. The present study demonstrates that the diffusion of Ca from the surrounding cementitious matrix into the dispersed catalyst particles plays an important role in the pozzolanic activity of the system.The authors acknowledge the funding by Fundação para a Ciência e Tecnologia through PTDC/ECM/113115/2009 and PEST-OE/CTM-UI0084/2011 grants.