Impaired emotional processing is a core feature of schizophrenia (SZ). Consistent findings suggested that abnormal emotional processing in SZ could be paralleled by a disrupted functional and ...structural integrity within the fronto-limbic circuitry. The effective connectivity of emotional circuitry in SZ has never been explored in terms of causal relationship between brain regions. We used functional magnetic resonance imaging and Dynamic Causal Modeling (DCM) to characterize effective connectivity during implicit processing of affective stimuli in SZ.
We performed DCM to model connectivity between amygdala (Amy), dorsolateral prefrontal cortex (DLPFC), ventral prefrontal cortex (VPFC), fusiform gyrus (FG) and visual cortex (VC) in 25 patients with SZ and 29 HC. Bayesian Model Selection and average were performed to determine the optimal structural model and its parameters.
Analyses revealed that patients with SZ are characterized by a significant reduced top-down endogenous connectivity from DLPFC to Amy, an increased connectivity from Amy to VPFC and a decreased driving input to Amy of affective stimuli compared to HC. Furthermore, DLPFC to Amy connection in patients significantly influenced the severity of psychopathology as rated on Positive and Negative Syndrome Scale.
Results suggest a functional disconnection in brain network that contributes to the symptomatic outcome of the disorder. Our findings support the study of effective connectivity within cortico-limbic structures as a marker of severity and treatment efficacy in SZ.
Este trabalho estuda o problema de compressão de imagens
de sensoriamento remoto segundo a ótica da codificação
conjunta fonte-canal.
É analisado o desempenho de métodos baseados em
quantização ...vetorial segundo o algoritmo LBG,
principalmente o COVQ (Channel Optimized Vector
Quantizer) bem como a quantização vetorial estruturada em
árvore. Dentro desse contexto, são propostos 2 novos
métodos para a resolução do problema: (1)Uma quantização
vetorial estruturada em árvores que leva em conta a
transmissão através de canais ruidosos, solução denominada
COTSVQ (Channel-Design Tree Strutured Vecotr Quantizer),
bem como (2) uma classe de métodos que se utiliza de
códigos corretores de erro sobre a estrutura progressiva
do TSVQ, de forma a proteger os dados de forma ativa
durante a transmissão. Os dois métodos propostos podem ser
combinados no mesmo compressor, de forma a originar uma
classe ampla de compressores adaptados à transmissão por
canais com ruído.
São apresentados resultados que comparam os desempenhos
dos métodos propostos com aqueles já existentes para uma
análise de desempenho, na situação de transmissão via
satélite de imagens captadas e comprimidas para uma taxa
de 1,5bpp.
Os resultados mostram que os métodos propostos são muito
menos complexos que os já existentes, porém conseguindo
atingir uma qualidade de imagem equivalente, ou, em alguns
casos, superior.
This work studies the problem of remote sensorng image
compression by joint source-channel coding.
The vector quantizer methods evaluated are those designed
with the LBG algorithm, the COVQ (channel-optimized vector
quantizer) algorithm as well as tree-structured vector
quantizer. The noisy channel is modelled as a BSC.
In this context, two news methods are proposed: (1) A tree-
structures vector quantizer that considers the
transmission through noisy channels (denominated CD-TSVQ),
and (2) a new class of compressors that uses forward error-
correcting codes over the TSVQ structure, as a way to
actively protect data during the transmission. The
twoproposed methods can be combined on the same compressor
architecture, resulting in a vast class of compressors
well-adapted to the transmission through noisy channels.
Results allowing the comparision of the proposed methods
with existing ones are presented. Performance evaluated in
a scenery where images are compressed to be transmited at
a rate of 1.5bpp. Results yield to the conclusion that the
porposed methods are much less complex than the existing
methods, yet achieve equivalent or, in some situations,
improved performance.
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Este trabalho estuda o problema de compressão de imagens
de sensoriamento remoto segundo a ótica da codificação
conjunta fonte-canal.
É ...analisado o desempenho de métodos baseados em
quantização vetorial segundo o algoritmo LBG,
principalmente o COVQ (Channel Optimized Vector
Quantizer) bem como a quantização vetorial estruturada em
árvore. Dentro desse contexto, são propostos 2 novos
métodos para a resolução do problema: (1)Uma quantização
vetorial estruturada em árvores que leva em conta a
transmissão através de canais ruidosos, solução denominada
COTSVQ (Channel-Design Tree Strutured Vecotr Quantizer),
bem como (2) uma classe de métodos que se utiliza de
códigos corretores de erro sobre a estrutura progressiva
do TSVQ, de forma a proteger os dados de forma ativa
durante a transmissão. Os dois métodos propostos podem ser
combinados no mesmo compressor, de forma a originar uma
classe ampla de compressores adaptados à transmissão por
canais com ruído.
São apresentados resultados que comparam os desempenhos
dos métodos propostos com aqueles já existentes para uma
análise de desempenho, na situação de transmissão via
satélite de imagens captadas e comprimidas para uma taxa
de 1,5bpp.
Os resultados mostram que os métodos propostos são muito
menos complexos que os já existentes, porém conseguindo
atingir uma qualidade de imagem equivalente, ou, em alguns
casos, superior.
This work studies the problem of remote sensorng image
compression by joint source-channel coding.
The vector quantizer methods evaluated are those designed
with the LBG algorithm, the COVQ (channel-optimized vector
quantizer) algorithm as well as tree-structured vector
quantizer. The noisy channel is modelled as a BSC.
In this context, two news methods are proposed: (1) A tree-
structures vector quantizer that considers the
transmission through noisy channels (denominated CD-TSVQ),
and (2) a new class of compressors that uses forward error-
correcting codes over the TSVQ structure, as a way to
actively protect data during the transmission. The
twoproposed methods can be combined on the same compressor
architecture, resulting in a vast class of compressors
well-adapted to the transmission through noisy channels.
Results allowing the comparision of the proposed methods
with existing ones are presented. Performance evaluated in
a scenery where images are compressed to be transmited at
a rate of 1.5bpp. Results yield to the conclusion that the
porposed methods are much less complex than the existing
methods, yet achieve equivalent or, in some situations,
improved performance.
A new biodegradable nanocomposite was obtained from layer-by-layer (LBL) technique using highly deacetylated chitosan and eucalyptus wood cellulose nanowhiskers (CNWs). Hydrogen bonds and ...electrostatic interactions between the negatively charged sulfate groups on the whisker surface and the ammonium groups of chitosan were the driving forces for the growth of the multilayered films. The film growth was followed by UV−vis spectroscopy through the maximum value of the absorption band at 194 nm and showed the deposition of 14.7 mg·m−2 of chitosan polymer in each cycle. Scanning electron microscopy showed high density and homogeneous distribution of CNWs adsorbed on each chitosan layer. Cross-section characterization of the assembled films indicates an average of ∼7 nm of thickness per bilayer. The results presented in this work indicate that the methodology used can be extended to different biopolymers for the design of new biobased nanocomposites in a wide range of applications such as biomedical and food packaging.
The oxidation of aqueous sulfide promoted by activated carbon (AC) was investigated. Raman, infrared, X-ray diffraction, ultraviolet–visible spectroscopy and electron paramagnetic resonance analyses ...show that AC oxidizes aqueous sulfide to form a complex mixture of polysulfides and sulfur oxide species. This oxidation is strongly promoted by the presence of oxygen surface groups introduced by oxidation of the AC as shown by kinetic measurements. These results are discussed in terms of the similarities the AC have with enzymatic systems, i.e. redox surface groups (e.g. quinone) combined with an efficient electron conduction system.
Aims We conducted a multi-centre, prospective, controlled, randomized trial to investigate the adjunctive role of ablation therapy to antiarrhythmic drug therapy in preventing atrial fibrillation ...(AF) relapses in patients with paroxysmal or persistent AF in whom antiarrhythmic drug therapy had already failed. Methods and results One hundred and thirty seven patients were randomized to ablation and antiarrhythmic drug therapy (ablation group) or antiarrhythmic drug therapy alone (control group). In the ablation group, patients underwent cavo-tricuspid and left inferior pulmonary vein (PV)-mitral isthmus ablation plus circumferential PV ablation. The primary end-point of the study was the absence of any recurrence of atrial arrhythmia lasting >30 s in the 1-year follow-up period, after 1-month blanking period. Three (4.4%) major complications were related to ablation: one patient had a stroke during left atrium ablation, another suffered transient phrenic paralysis, and the third had a pericardial effusion which required pericardiocentesis. After 12 months of follow-up, 63/69 (91.3%) control group patients had at least one AF recurrence, whereas 30/68 (44.1%) (P<0.001) ablation group patients had atrial arrhythmia recurrence (four patients had atrial flutter, 26 patients AF). Conclusion Ablation therapy combined with antiarrhythmic drug therapy is superior to antiarrhythmic drug therapy alone in preventing atrial arrhythmia recurrences in patients with paroxysmal or persistent AF in whom antiarrhythmic drug therapy has already failed.
The northern Adriatic Sea hosts patches of rock formations that have given rise to large biodiversity not otherwise found on the predominantly sandy and flat seabed. Various hypotheses have been ...invoked concerning the origin of these features, which are widespread in the northern Adriatic Sea and have been intensively studied since the eighteenth century. Here, we provide a significant advancement of knowledge in the lithification process associated with these peculiar rock formations. This study is based on geological, geophysical and mineralogical analyses performed on 45 rock outcrops identified in the study area. A key result of our analysis is the reconciliation of the different models related to the genesis of the northern Adriatic Sea outcrops, i.e., Holocene beach rocks that typically formed in the intertidal zone; cementation of paleo-channel systems, implying a groundwater influence; and methane-derived carbonates. Regardless of the depositional environment, we highlight the relationship between sediments and the processes that led to their evolution into the sandstone formation. We suggest that a common cementation process occurred in the various sedimentary deposits that are representative of different environments of the northern Adriatic Sea and was related to the post depositional precipitation of methane-derived carbonates. Our findings highlight the potential key role of widespread methane seepage from very shallow marine environments into the water column and then, eventually, into the atmosphere as a potential source of an increasing greenhouse gas.
•The northern Adriatic Sea hosts hundreds peculiar rock outcrops, some of which are unique geosites.•Most of the northern Adriatic Sea rock outcrops are methane-derived carbonates.•The northern Adriatic Sea is an excellent natural laboratory to study methane seepage.•Are the northern Adriatic Sea geosites also associated with groundwater seepage?
The aim of our study was to determine the incidence of asymptomatic recurrences of atrial fibrillation (AF) by daily transtelephonic (TT) electrocardiographic (ECG) monitoring, as compared with ...standard ECG and 24-h Holter recording, in patients who underwent radiofrequency catheter ablation (RCA) of AF.
The efficacy of RCA of AF is usually evaluated by means of patients’ symptoms.
Seventy-two patients with paroxysmal (n = 37) or persistent (n = 35) drug-refractory AF underwent circumferential RCA of the pulmonary vein (PV) ostia. Left isthmus ablation was performed in 57 patients, and cavotricuspid isthmus ablation was done in 69 patients. Patients were scheduled to obtain an ECG and Holter recordings one and four months after ablation, as well as a daily TT ECG, from 30 to 120 days after ablation or in the event of symptoms.
A total of 5,585 TT ECGs were obtained (mean 77.5 per patient). In 20 patients (27.8%), AF recurrences were recorded during TT ECG, whereas ECG and Holter monitoring revealed AF recurrences in 10 patients (13.9%, p = 0.001). Ten patients had at least one asymptomatic AF recurrence, and eight were completely asymptomatic. The ECG recorded in the event of symptoms always showed AF.
Transtelephonic ECG is better than standard ECG and 24-h Holter recordings in evaluating AF relapses after RCA, thus decreasing the short-term success of ablation from 86% to 72%. The absence of symptoms should not be interpreted as absence of AF, as 50% of patients were asymptomatic during at least one AF episode.
The in vitro antifungal activity of nine dirutheniumpentadithiocarbamate complexes C1-C9 was investigated and assessed for its activity against four different fungal species with clinical interest ...and related to invasive fungal infections (IFIs), such as Candida spp. C. albicans (two clinical isolates), C. glabrata, C. krusei, C. parapsolisis, C. tropicalis, C.dubliniensis (six clinical isolates), Paracoccidioides brasiliensis (seven clinical isolates), Cryptococcus neoformans and Sporothrix schenckii. All synthesized complexes C1-C9 and also the free ligands L1-L9 were submitted to in vitro tests against those fungi and the results are very promising, since some of the obtained MIC (minimal inhibitory concentration) values were very low (from 10-6 mol mL-1 to 10-8 mol mL-1) against all investigated clinically relevant fungal pathogens, except for C. glabrata, that the MIC values are close to the ones obtained for fluconazole, the standard antifungal agent tested. Preliminary structure-activity relations (SAR) might be suggested and a strong influence from steric and lipophilic parameters in the antifungal activity can be noticed. Cytotoxicity assays (IC50) showed that the complexes are not as toxic (IC50 values are much higher-30 to 200 fold-than MIC values). These ruthenium complexes are very promising lead compounds for novel antifungal drug development, especially in IFIs, one of most harmful emerging infection diseases (EIDs).
Vaccines have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) morbidity and mortality, yet emerging variants challenge their effectiveness. The prevailing approach to updating ...vaccines targets the antibody response, operating under the presumption that it is the primary defense mechanism following vaccination or infection. This perspective, however, can overlook the role of T cells, particularly when antibody levels are low or absent. Here we show, through studies in mouse models lacking antibodies but maintaining functional B cells and lymphoid organs, that immunity conferred by prior infection or mRNA vaccination can protect against SARS-CoV-2 challenge independently of antibodies. Our findings, using three distinct models inclusive of a novel human/mouse ACE2 hybrid, highlight that CD8
T cells are essential for combating severe infections, whereas CD4
T cells contribute to managing milder cases, with interferon-γ having an important function in this antibody-independent defense. These findings highlight the importance of T cell responses in vaccine development, urging a broader perspective on protective immunity beyond just antibodies.
PDF
