The impact of CdSe/ZnS Quantum Dots in cells of Medicago sativa in suspension culture

Abstract Background: Nanotechnology has the potential to provide agriculture with new tools that may be used in the rapid detection and molecular treatment of diseases and enhancement of plant ability to absorb nutrients, among others. Data on nanoparticle toxicity in plants is largely heterogeneous with a diversity of physicochemical parameters reported, which difficult generalizations. Here a cell biology approach was used to evaluate the impact of Quantum Dots (QDs) nanocrystals on plant cells, including their effect on cell growth, cell viability, oxidative stress and ROS accumulation, besides their cytomobility. Results: A plant cell suspension culture of Medicago sativa was settled for the assessment of the impact of the addition of mercaptopropanoic acid coated CdSe/ZnS QDs. Cell growth was significantly reduced when 100 mM of mercaptopropanoic acid -QDs was added during the exponential growth phase, with less than 50% of the cells viable 72 hours after mercaptopropanoic acid -QDs addition. They were up taken by Medicago sativa cells and accumulated in the cytoplasm and nucleus as revealed by optical thin confocal imaging. As part of the cellular response to internalization, Medicago sativa cells were found to increase the production of Reactive Oxygen Species (ROS) in a dose and time dependent manner. Using the fluorescent dye H2DCFDA it was observable that mercaptopropanoic acid-QDs concentrations between 5-180 nM led to a progressive and linear increase of ROS accumulation. Conclusions: Our results showed that the extent of mercaptopropanoic acid coated CdSe/ZnS QDs cytotoxicity in plant cells is dependent upon a number of factors including QDs properties, dose and the environmental conditions of administration and that, for Medicago sativa cells, a safe range of 1-5 nM should not be exceeded for biological applications.

Sedimentation in parasitological coproscopy

A sedimentation technique is described, in which a fecal suspension is placed on top of an aqueous sucrose solution of specific gravity 1.015 g/cm³. Using 100 by 15 mm test tubes, duplicate gravity sedimentation experiments were made using homogenized fecal suspensions (single-columns) and fecal suspensions placed on top of clear columns (double-columns). Egg- and cyst-counts, and turbidity determinations were made in the sediments obtained after definite time intervals. Most Ascaris lumbricoides, Trichuris trichiura and Ancylostomidae eggs sedimented within 20 minutes in single - and between 30 and 60 minutes in double-columns. Giardia duodenalis cysts required longer periods to sediment in double - than in single-columns; after 180 minutes (the maximum period of observation), double-column sediments produced 60.0% of the counts of single-columns. Double-column sediments were consistently less turbid than single-column ones

Development of a high-throughput monitoring technique of bacteria photodynamic inactivation

Summary form only given. Bacterial infections and the fight against them have been one of the major concerns of mankind since the dawn of time. During the `golden years' of antibiotic discovery, during the 1940-90s, it was thought that the war against infectious diseases had been won. However currently, due to the drug resistance increase, associated with the inefficiency of discovering new antibiotic classes, infectious diseases are again a major public health concern. A potential alternative to antibiotic treatments may be the antimicrobial photodynamic inactivation (PDI) therapy. To date no indication of antimicrobial PDI resistance development has been reported. However the PDI protocol depends on the bacteria species [1], and in some cases on the bacteria strains, for instance Staphylococcus aureus [2]. Therefore the development of PDI monitoring techniques for diverse bacteria strains is critical in pursuing further understanding of such promising alternative therapy. The present works aims to evaluate Fourier-Transformed-Infra-Red (FT-IR) spectroscopy to monitor the PDI of two model bacteria, a gram-negative (Escherichia coli) and a gram-positive (S. aureus) bacteria. For that a high-throughput FTIR spectroscopic method was implemented as generally described in Scholz et al. [3], using short incubation periods and microliter quantities of the incubation mixture containing the bacteria and the PDI-drug model the known bactericidal tetracationic porphyrin 5,10,15,20-tetrakis (4-N, N, Ntrimethylammoniumphenyl)-porphyrin p-tosylate (TTAP4+). In both bacteria models it was possible to detect, by FTIR-spectroscopy, the drugs effect on the cellular composition either directly on the spectra or on score plots of principal component analysis. Furthermore the technique enabled to infer the effect of PDI on the major cellular biomolecules and metabolic status, for example the turn-over metabolism. In summary bacteria PDI was monitored in an economic, rapid (in minutes- , high-throughput (using microplates with 96 wells) and highly sensitive mode resourcing to FTIR spectroscopy, which could serve has a technological basis for the evaluation of antimicrobial PDI therapies efficiency.

Fast unsupervised technique for extraction of endmembers spectra from hyperspectral data

One of the most challenging task underlying many hyperspectral imagery applications is the linear unmixing. The key to linear unmixing is to find the set of reference substances, also called endmembers, that are representative of a given scene. This paper presents the vertex component analysis (VCA) a new method to unmix linear mixtures of hyperspectral sources. The algorithm is unsupervised and exploits a simple geometric fact: endmembers are vertices of a simplex. The algorithm complexity, measured in floating points operations, is O (n), where n is the sample size. The effectiveness of the proposed scheme is illustrated using simulated data.

Immunoperoxidase for the detection for the detection of antibodies in cerebrospinal fluid in neurocysticercosis: use of Cysticercus cellulosae and Cysticercus longicollis particles fixed on microscopy slides

The ORF strain of Cysticercus longicollis represents an important model for the study of heterologous antigens in the immunodiagnosis of neurocysticercosis (NC). The immunoperoxidase (IP) technique was standardized using a particulate antigen suspension of Cysticercus longicollis (Cl) and Cysticercus cellulosae (Cc). Cerebrospinal fluid (CSF) samples were incubated on the antigen fixed to microscopy slides; the conjugate employed was anti-IgG-peroxidase and the enzymatic reaction was started by covering the slides with chromogen solution (diaminobenzidine/H2O2). After washing with distilled water, the slide was stained with 2% malachite green in water. Of the CSF samples from 21 patients with NC, 19 (90.5%) were positive, whereas the 8 CSF samples from the control group (100%) were negative. The results of the IP-Cl test applied to 127 CSF samples from patients with suspected NC showed 28.3% reactivity as opposed to 29.1 % for the IP-Cc test. The agreement index for the IP test (Cl x Cc) was 94.2%, with no significant difference between the two antigens.

Cross-Reactions between Toxocara canis and Ascaris suum in the diagnosis of visceral larva migrans by western blotting technique

Visceral larva migrans (VLM) is a clinical syndrome caused by infection of man by Toxocara spp, the common roundworm of dogs and cats. Tissue migration of larval stages causes illness specially in children. Because larvae are difficult to detect in tissues, diagnosis is mostly based on serology. After the introduction of the enzyme-linked immunosorbent assay (ELISA) using the larval excretory-secretory antigen of T. canis (TES), the diagnosis specificity was greatly improved although cross-reactivity with other helminths are still being reported. In Brazil, diagnosis is routinely made after absorption of serum samples with Ascaris suum antigens, a nematode antigenicaly related with Ascaris lumbricoides which is a common intestinal nematode of children. In order to identify T. canis antigens that cross react to A. suum antigens we analyzed TES antigen by SDS-PAGE and Western blotting techniques. When we used serum samples from patients suspected of VLM and positive result by ELISA as well as a reference serum sample numerous bands were seen (molecular weight of 210-200 kDa, 116-97 kDa, 55-50 kDa and 35-29 kDa). Among these there is at least one band with molecular weight around 55-66 kDa that seem to be responsible for the cross-reactivity between T. canis e A. suum once it disappears when previous absorption of serum samples with A. suum antigens is performed

SIMPLIFIED DIAGNOSIS OF MALARIA INFECTION: GFM/PCR/ELISA A SIMPLIFIED NUCLEIC ACID AMPLIFICATION TECHNIQUE BY PCR/ELISA

We report an adaptation of a technique for the blood sample collection (GFM) as well as for the extraction and amplification of Plasmodium DNA for the diagnosis of malaria infection by the PCR/ELISA. The method of blood sample collection requires less expertise and saves both time and money, thus reducing the cost by more than half. The material is also suitable for genetic analysis in either fresh or stored specimens prepared by this method.

ANALYSIS OF Treponema pallidum RECOMBINANT ANTIGENS FOR DIAGNOSIS OF SYPHILIS BY WESTERN BLOTTING TECHNIQUE

Three GST fusion recombinant antigen of Treponema pallidum, described as GST-rTp47, GST-rTp17 and GST-rTp15 were analyzed by Western blotting techniques. We have tested 53 serum samples: 25 from patients at different clinical stages of syphilis, all of them presenting anti-treponemal antibody, 25 from healthy blood donors and three from patients with sexually transmitted disease (STD) other than syphilis. Almost all samples from patients with syphilis presented a strong reactivity with GST-rTp17 antigen. Some samples were non-reactive or showed a weak reaction with GST-rTp47 and/or GST-rTp15, and apparently there was no correlation with the stage of disease. There was no seropositivity among blood donors. No sample reacted with purified GST. We concluded that due to their specificity these recombinant antigens can be used as GST fusion protein for development of syphilis diagnostic assays.

Full analysis of suspension geometry and chassis performance of Formula Student racing car

Formula Student events gather engineering students, who compete, designing, building and racing single-seater cars. The team of ISEP is working on its first car that soon will take part in this competition. This work aims to analyze the current design’s chassis, focusing on suspension geometry and frame’s performance. After analyzing results of the tests planned suggestions, that can be taken into consideration during design process of next cars will be presented. As the car has not been tested yet this work can also be helpful to explain its performance on the track later.

Study of materials, technique and conservation treatment of Sinfonia Heroica by Dordio Gomes

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Conservação e Restauro

The materials, technique, conservation treatment and after-care of interior de um convento

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Conservação e Restauro, especialização em pintura sobre tela

Evaluation of the formalin-Tween concentration technique for parasitic detection

The formalin-Tween sedimentation method was compared with the formalin-ether sedimentation for parasitic detection. Of a total 297 fecal specimens examined, 72.1% were positive. The formalin-tween technique was effective for ascertaining helminths, particularly Ascaris lumbricoides, Trichuris trichiura and hookworm eggs; however it has less capability for protozoa detection. This method is simple, inexpensive, less time consuming and highly sensitive when detecting the parasitic infection, particularly when focusing on helminth eggs.

Assessment of the rapid test based on an immunochromatography technique for detecting anti-Treponema pallidum antibodies

A rapid test based on an immunochromatography assay - Determine™ Syphilis TP (Abbott Lab.) for detecting specific antibodies to Treponema pallidum was evaluated against serum samples from patients with clinical, epidemiological and serological diagnosis of syphilis, patients with sexually transmitted disease other than syphilis, and individuals with negative serology for syphilis. The Determine™ test presented the sensitivity of 93.6%, specificity of 92.5%, and positive predictive value and negative predictive value of 95.2% and 93.7%, respectively. One serum sample from patient with recent latent syphilis showed a prozone reaction. Determine™ is a rapid assay, highly specific and easy to perform. This technique obviates the need of equipment and its diagnostic features demonstrate that it may be applicable as an alternative assay for syphilis screening under some emergency conditions or for patients living in remote localities.

Simple Kinematic Design for Evading the Forced Oscillation of a Car-Wheel Suspension System

An adaptive control damping the forced vibration of a car while passing along a bumpy road is investigated. It is based on a simple kinematic description of the desired behavior of the damped system. A modified PID controller containing an approximation of Caputo’s fractional derivative suppresses the high-frequency components related to the bumps and dips, while the low frequency part of passing hills/valleys are strictly traced. Neither a complete dynamic model of the car nor ’a priori’ information on the surface of the road is needed. The adaptive control realizes this kinematic design in spite of the existence of dynamically coupled, excitable internal degrees of freedom. The method is investigated via Scicos-based simulation in the case of a paradigm. It was found that both adaptivity and fractional order derivatives are essential parts of the control that can keep the vibration of the load at bay without directly controlling its motion.

Histoplasma capsulatum fungemia in patients with acquired immunodeficiency syndrome: detection by lysis-centrifugation blood-culturing technique

Progressive disseminated histoplasmosis (PDH) is an increasingly common cause of infection in patients with acquired immune deficiency syndrome (AIDS). We report 21 cases of PDH associated with AIDS diagnosed by lysis-centrifugation blood culture method. The most prevalent clinical findings were fever, weight loss, respiratory symptoms, and mucocutaneous lesions. Chest roentgenogram showed diffuse pulmonary infiltrates in 13 of 21 patients (62%). Brochoalveolar fluid has yelded positive culture in four patients only in medium with cycloheximide.