979 research outputs found
Linear and Nonlinear Spectroscopy by a Common-Path Birefringent Interferometer
© 1995-2012 IEEE. We introduce a passive common-path interferometer to replace Michelson interferometers in the Fourier-Transform spectroscopy. Our device exploits birefringence to introduce a highly accurate delay between two orthogonal polarization components by continuously varying the material thickness. Due to its inherent delay stability and reproducibility, it can be used even for short wavelengths (down to ∼200 nm) without the need for any active control or position tracking. We first demonstrate its performances in linear spectroscopy, by implementing a spectrometer and a spectrophotometer. We then extend its use to nonlinear spectroscopy and, in combination with lock-in detection at MHz modulation frequencies, illustrate its application to pump-probe spectroscopy with high sensitivity (ΔT/T 500 nm) and to broadband stimulated Raman scattering microscopy in the CH stretching region
Determinação do carbono da biomassa microbiana do solo: Método da fumigação-extração.
Precondicionamento das amostras. Procedimento analítico. Cálculo da BMS.bitstream/CNPAB-2010/27227/1/doc037.pd
Tallimustine in advanced previously untreated colorectal cancer, a phase II study.
Tallimustine is a novel benzoyl mustard derivative from distamycin A with a unique mode of action. It is a DNA minor groove binder and produces highly sequence-specific alkylations. Previous studies have shown significant anti-tumour effects in animal models. We performed a phase II study in previously untreated patients with advanced colorectal cancer, using a schedule of i.v. bolus infusions of 900 microgram m-2 once every 4 weeks. Seventeen patients were enrolled, and no responses were documented in 14 evaluable patients. Toxicity mainly consisted a highly selective neutropenia, which warrants further investigation of this agent in combination with myeloid growth factors
Microbial soil quality indicators under different crop rotations and tillage management.
An experiment was carried out under field conditions to assess the effects of soil management (no-tillage- NT and conventional tillage- CT) and crop rotation systems on microbial biomass-C (Cmic), basal soil respiration (BSR), metabolic quotient (qCO2), soil organic carbon content (Corg) and microbial carbon to organic carbon ratio (Cmic/Corg). Soil samples were collected on an area cultivated with wheat as winter crop and soybean as summer crop, both in rotation with vetch, maize and oats. Samples were also collected in a secondary forest used as reference. Data of each management system (NT and CT) were compared to forest area by ?t? test (p<0.05) and crop rotations were compared by Tukey test (p<0.05). All data were submitted to multivariate analysis (Principal Component Analysis - PCA). There were observed significant differences (?t? test; p<0.05) for Cmic, BSR, qCO2 and Cmic/Corg between NT and CT, by which NT values resemble those for forest area. For crop rotations significant differences (Tukey test; p<0.05) were found only for BSR and qCO2. The sum of the two first principal components on the PCA explained about 75% of the data variation. PCA showed NT closest to forest area than CT, especially treatments with soybean and vetch as consecutive crops. The forest area-NT clustering was mostly due to Cmic and Cmic/Corg relationship. Results indicate that the NT system is more sustainable than the CT system and can contribute for the accumulation a greater quantity of carbon in soil
Fixação de fósforo por um Latossolo e determinação do valor X.
Ensaio conduzido em laboratório para avaliar a capacidade de fixação de fósforo dos horizontes A1, A3 e B22 de latossolo roxo distrófico. Foi também determinado o valor X de WAUGH & FITS (1966) dos três horizontes. Os principais resultados são apresentados a seguir: O horizonte B22 foi que apresentou maior capacidade de fixação de fósforo, seguido pelo A3 e, finalmente, pelo A1. Os valores X encontrados foram 350 ppm225ppm e 175 ppm para os horizontes B22, A3 eA1, respectivamente. Houve uma relação muito estreita entre as quantidades de P adicionadas e as fixadas pelos três horizontes
Fixação de fósforo por um latossolo do Estado de Minas Gerais.
Foi estudada absorção do fósforo por amostras de três horizontes, A1, (0-22cm), A3(22-56cm) e B22(155-200cm), de um Latossolo do Estado de Minas Gerais por meio da isoterma de Langmuir. Os valores de adsorção máxima (b) e da constante de seletividade (K) calculados a partir da forma linear da equação de Langmuir foram correlacionados com algumas características físicas e químicas apresentadas pelos citados horizontes. Os resultados encontrados permitiram concluir que: As isotérmicas de adsorção mostram duas regiões distintas: aquela em que o fosfato é fortemente retido foi convenientemente descrita pela equação de Langmuir. Em virtude da diversidade das características físicas e químicas dos horizontes houve grande variação nos valores de adsorção máxima (b) e da constante seletividade (K)
Construction of a secondary metabolite deficient penicillium chrysogenum strain as a generic production host for secondary metabolites
Secondary metabolism of the filamentous fungus Penicillium chrysogenum has been intensively explored to relate specific secondary metabolites to their respective biosynthetic gene clusters. We have removed the three main biosynthetic gene clusters that specify the antibiotic penicillin, the mycotoxin roquefortine and the yellow pigment chrysogine, in order to generate a secondary metabolite deficient strain. This strain produces increased levels of other secondary metabolites some of which have not been detected before. The strain and its biosynthetic potential will now be further investigated for the expression of novel enzymes and biosynthetic pathways to make the synthesis of antibiotics and other secondary metabolites more specific and efficient. Using structure guided protein engineering new enzymes will be further designed and optimized for the construction of a newly designed biosynthetic pathway into a novel platform strain
Correlation between neurotrasmitter levels and anxietyrelated behaviours in cats
Introduction:
The present study aims to evaluate the existing correlations between neurotransmitter levels and
anxiety-related aggressive behaviour.
Materials and methods:
22 adult cats (age > 6months; no pharmacological therapy for behaviour problems) were grouped
according to three different levels of aggressive behaviour: Group 1 (N=11): rare aggressive
attacks, anxiety and aggressive-related behaviour problems reported by the owner; Group 2 (N=4):
frequent aggressive attacks (n attacks > 12/year); Group 3 (N=7): control, no aggressive attacks
reported by the owners. An accurate questionnaire focusing on anxiety and aggressive behaviour
was filled in for every subject and evaluated by a DVM certified Specialist in Veterinary
Behavioural Medicine. Blood samples were collected in EDTA for all the subjects for
neurotransmitters analysis (standard blood processing procedures for HPLC neurotransmitter
analysis were applied). HPLC analysis was carried out for the following neurotransmitters:
Dopamine precursor LDOPA, dopamine DA, noradrenalin NA, adrenalin A, serotonin SE levels in
plasma and platelets; 5-hidrossiindolacetic acid HIAA (serotonin metabolite) and Homovanillic acid
(dopamine metabolite) in platelets. SAS \uae statistic package was applied to data analysis: FREQ,
MEAN and NPAR1WAY procedures were applied; the analysis of variance was carried out using a
Kruscal-Wallis one-way ANOVA.Results:
The results indicate that during the history taking session, the origin of the cat, age at weaning and
human family structure are very helpful in aggressive behaviour evaluation, furthermore
nervousness, shyness and fearfulness related information are closely linked to anxiety related
problems. Higher levels of NA (pg/ml), DA (pg/ml), LDOPA plasma (pg/ml), LDOPA platelet
(pg/ml) were found in Control group (P 640.05). A correlation between neurotransmitter
concentrations and anxiety related behavioural problems has been calculated.
Discussion:
The obtained results suggest, in particular, that the reduction in platelet DA levels could be related
to aggressive behaviour towards animals and human beings. Further analysis is needed to improve
the knowledge of the complex relations between nervous system and behaviour. In addition the
investigation of the genetic basis of behaviour could supply powerful tools in the understanding of
anxiety and aggressiveness in companion animals
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