70 research outputs found
Adjustment in the Euro Area and Regulation of Product and Labour Markets: An Empirical Assessment
This paper assesses the adjustment mechanism in the euro area. Results show that the real exchange rate (REER) adjusts in such a way to redress cyclical divergences and that after monetary unification REER dynamics have become less reactive to country-specific shocks but also less persistent. It is found that regulations, notably affecting price and wage nominal flexibility and employment protection, play a role in the adjustment mechanism. Indicators of product and labour regulations appear to matter forboth the reaction of price competitiveness to cyclical divergences (differences between national and euro-area output gaps) and for the inertia of competitiveness indicators. Moreover, regulations appear to matter also for the extent to which common shocks may end up producing country-specific effects on the price competitiveness, as revealed by their interaction with proxies of unobservable common shocks along the lines of the methodology developed in Blanchard and Wolfers (2000). In light of the tendency towards less stringent regulations in past decades, the results seem consistent with the observed reduction in the persistence of inflation differentials, and has have implications for the design of adjustment-friendly product and labour market reforms.
Dispersion of Ventricular Depolarization-Repolarization
Background
—We retrospectively investigated the value of clinical and ECG findings as well as QT-QRS dispersion in predicting the risk of sudden death in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).
Methods and Results
—Duration and interlead variability of the QT interval and QRS complex were measured manually from standard ECGs in 20 sudden death victims with ARVC diagnosed at autopsy (group I), in 20 living ARVC patients with sustained ventricular tachycardia (group II), in 20 living ARVC patients with ≤3 consecutive premature ventricular beats (group III), and in 20 control subjects (group IV). QT and QRS dispersions were greater in group I (77.5±10.6 ms for QT and 45.7±8.1 ms for QRS) compared with group II (64.5±13.9 ms for QT [
P
=0.001] and 33.5±8.7 ms for QRS [
P
=0.0004]) and in group II compared with group III (48±8.9 ms for QT [
P
<0.0001] and 28±5.2 ms for QRS [
P
<0.0001]) and group IV (33.5±4.8 ms for QT [
P
<0.0001] and 18.5±3.6 ms for QRS [
P
<0.0001]). Negative T wave beyond V
1
and syncope were statistically more frequent in group I (
P
=0.02 and
P
=0.007, respectively). On multivariate analysis, QRS dispersion remained an independent predictor of sudden death (
P
<0.0001), followed by syncope (
P
=0.09). In assessing risk of sudden death, QRS dispersion ≥40 ms had a sensitivity and specificity of 90% and 77%, respectively; QT dispersion >65 ms, 85% and 75%, respectively; negative T wave beyond V
1
, 85% and 42%, respectively; and syncope, 40% and 90%, respectively.
Conclusions
—QRS dispersion (≥40 ms) was the strongest independent predictor of sudden death in ARVC. Syncope, QT dispersion >65 ms, and negative T wave beyond V
1
refined arrhythmic risk stratification in these patients
Whole-brain functional imaging to highlight differences between the diurnal and nocturnal neuronal activity in zebrafish larvae
Most living organisms show highly conserved physiological changes following a
24-hour cycle which goes by the name of circadian rhythm. Among experimental
models, the effects of light-dark cycle have been recently investigated in the
larval zebrafish. Owing to its small size and transparency, this vertebrate
enables optical access to the entire brain. Indeed, the combination of this
organism with light-sheet imaging grants high spatio-temporal resolution
volumetric recording of neuronal activity. This imaging technique, in its
multiphoton variant, allows functional investigations without unwanted visual
stimulation. Here, we employed a custom two-photon light-sheet microscope to
study whole-brain differences in neuronal activity between diurnal and
nocturnal periods in larval zebrafish. We describe for the first time an
activity increase in the low frequency domain of the pretectum and a
frequency-localised activity decrease of the anterior rhombencephalic turning
region during the nocturnal period. Moreover, our data confirm a nocturnal
reduction in habenular activity. Furthermore, whole-brain detrended fluctuation
analysis revealed a nocturnal decrease in the self-affinity of the neuronal
signals in parts of the dorsal thalamus and the medulla oblongata. Our data
show that whole-brain nonlinear light-sheet imaging represents a useful tool to
investigate circadian rhythm effects on neuronal activity.Comment: 18 pages, 6 figure
Effects of excitation light polarization on fluorescence emission in two-photon light-sheet microscopy
Light-sheet microscopy (LSM) is a powerful imaging technique that uses a
planar illumination oriented orthogonally to the detection axis. Two-photon
(2P) LSM is a variant of LSM that exploits the 2P absorption effect for sample
excitation. The light polarization state plays a significant, and often
overlooked, role in 2P absorption processes. The scope of this work is to test
whether using different polarization states for excitation light can affect the
detected signal levels in 2P LSM imaging of typical biological samples with a
spatially unordered dye population. Supported by a theoretical model, we
compared the fluorescence signals obtained using different polarization states
with various fluorophores (fluorescein, EGFP and GCaMP6s) and different samples
(liquid solution and fixed or living zebrafish larvae). In all conditions, in
agreement with our theoretical expectations, linear polarization oriented
parallel to the detection plane provided the largest signal levels, while
perpendicularly-oriented polarization gave low fluorescence signal with the
biological samples, but a large signal for the fluorescein solution. Finally,
circular polarization generally provided lower signal levels. These results
highlight the importance of controlling the light polarization state in 2P LSM
of biological samples. Furthermore, this characterization represents a useful
guide to choose the best light polarization state when maximization of signal
levels is needed, e.g. in high-speed 2P LSM.Comment: 16 pages, 4 figures. Version of the manuscript accepted for
publication on Biomedical Optics Expres
Fast whole-brain imaging of seizures in zebrafish larvae by two-photon light-sheet microscopy
Light-sheet fluorescence microscopy (LSFM) enables real-time whole-brain
functional imaging in zebrafish larvae. Conventional one photon LSFM can
however induce undesirable visual stimulation due to the use of visible
excitation light. The use of two-photon (2P) excitation, employing
near-infrared invisible light, provides unbiased investigation of neuronal
circuit dynamics. However, due to the low efficiency of the 2P absorption
process, the imaging speed of this technique is typically limited by the
signal-to-noise-ratio. Here, we describe a 2P LSFM setup designed for
non-invasive imaging that enables quintuplicating state-of-the-art volumetric
acquisition rate of the larval zebrafish brain (5 Hz) while keeping low the
laser intensity on the specimen. We applied our system to the study of
pharmacologically-induced acute seizures, characterizing the spatial-temporal
dynamics of pathological activity and describing for the first time the
appearance of caudo-rostral ictal waves (CRIWs).Comment: Replacement: accepted version of the manuscript, to be published in
Biomedical Optics Express. 36 pages, 15 figure
Dual-beam confocal light-sheet microscopy via flexible acousto-optic deflector
Confocal detection in digital scanned laser light-sheet fluorescence microscopy (DSLM) has been established as a gold standard method to improve image quality. The selective line detection of a complementary metal-oxide-semiconductor camera (CMOS) working in rolling shutter mode allows the rejection of out-of-focus and scattered light, thus reducing background signal during image formation. Most modern CMOS have two rolling shutters, but usually only a single illuminating beam is used, halving the maximum obtainable frame rate. We report on the capability to recover the full image acquisition rate via dual confocal DSLM by using an acousto-optic deflector. Such a simple solution enables us to independently generate, control and synchronize two beams with the two rolling slits on the camera. We show that the doubling of the imaging speed does not affect the confocal detection high contrast
Tyrosine phosphorylation modulates peroxiredoxin-2 activity in normal and diseased red cells
Peroxiredoxin-2 (Prx2) is the third most abundant cytoplasmic protein in red blood cells. Prx2 belongs to a well-known family of antioxidants, the peroxiredoxins (Prxs), that are widely expressed in mammalian cells. Prx2 is a typical, homodimeric, 2-Cys Prx that uses two cysteine residues to accomplish the task of detoxifying a vast range of organic peroxides, H2O2, and peroxynitrite. Although progress has been made on functional characterization of Prx2, much still remains to be investigated on Prx2 post-translational changes. Here, we first show that Prx2 is Tyrosine (Tyr) phosphorylated by Syk in red cells exposed to oxidation induced by diamide. We identified Tyr-193 in both recombinant Prx2 and native Prx2 from red cells as a specific target of Syk. Bioinformatic analysis suggests that phosphorylation of Tyr-193 allows Prx2 conformational change that is more favorable for its peroxidase activity. Indeed, Syk-induced Tyr phosphorylation of Prx2 enhances in vitro Prx2 activity, but also contributes to Prx2 translocation to the membrane of red cells exposed to diamide. The biologic importance of Tyr-193 phospho-Prx2 is further supported by data on red cells from a mouse model of humanized sickle cell disease (SCD). SCD is globally distributed, hereditary red cell disorder, characterized by severe red cell oxidation due to the pathologic sickle hemoglobin. SCD red cells show Tyr-phosphorylated Prx2 bound to the membrane and increased Prx2 activity when compared to healthy erythrocytes. Collectively, our data highlight the novel link between redox related signaling and Prx2 function in normal and diseased red cells
A Dietary Assessment Training Course Path: The Italian IV SCAI Study on Children Food Consumption
The eating patterns in a population can be estimated through dietary surveys in which open-ended assessment methods, such as diaries and interviews, or semi-quantitative food frequency questionnaires are administered. A harmonized dietary survey methodology, together with a standardized operational procedure, in conducting the study is crucial to ensure the comparability of the results and the accuracy of information, thus reducing uncertainty and increasing the reliability of the results. Dietary patterns (i) include several target variables (foods, energy and nutrients, other food components), (ii) require several explanatory variables (age, gender, anthropometric measurements, socio-cultural and economic characteristics, lifestyle, preferences, attitudes, beliefs, organization of food-related activities, etc.), and (iii) have impacts in several domains: imbalance diets; acute and chronic exposures affect health, specifically non-communicable diseases; and then sanitary expenditure. On the other hand, food demand has impacts on the food system: production, distribution, and food services system; food wastes and other wastes generated by food-related activities of the households (e.g., packaging disposal) have consequences on the “health of the planet” which in turn can have effects on human health. Harmonization and standardization of measurement methods and procedures in such a complex context require an ad hoc structured information system made by databases (food nomenclatures, portion sizes, food atlas, recipes) and methodological tools (quantification methods, food coding systems, assessment of nutritional status, data processing to extrapolate what we consider validated dietary data). Establishing a community of professionals specialized in dietary data management could lead to build a surveillance system for monitoring eating habits in the short term, thus reducing costs, and to arrange a training re-training system. Creating and maintaining the dietary data managers community is challenging but possible. In this context, the cooperation between the CREA Research Centre for Food and Nutrition and the Italian National Health Institute (ISS) promoted and supported by the Italian Ministry of Health may represent a model of best practice that can ensure a continuous training for the professional community carrying out a nutritional study
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