253 research outputs found
Attention networks and the intrinsic network structure of the human brain
Attention network theory distinguishes three independent systems, each supported by its own distributed network: an alerting network to deploy attentional resources in anticipation, an orienting network to direct attention to a cued location, and a control network to select relevant information at the expense of concurrently available information. Ample behavioral and neuroimaging evidence supports the dissociation of the three attention domains. The strong assumption that each attentional system is realized through a separable network, however, raises the question how these networks relate to the intrinsic network structure of the brain. Our understanding of brain networks has advanced majorly in the past years due to the increasing focus on brain connectivity. The brain is intrinsically organized into several large-scale networks whose modular structure persists across task states. Existing proposals on how the presumed attention networks relate to intrinsic networks rely mostly on anecdotal and partly contradictory arguments. We addressed this issue by mapping different attention networks at the level of cifti-grayordinates. Resulting group maps were compared to the group-level topology of 23 intrinsic networks, which we reconstructed from the same participants' resting state fMRI data. We found that all attention domains recruited multiple and partly overlapping intrinsic networks and converged in the dorsal fronto-parietal and midcingulo-insular network. While we observed a preference of each attentional domain for its own set of intrinsic networks, implicated networks did not match well to those proposed in the literature. Our results indicate a necessary refinement of the attention network theory.Deutsche Forschungsgemeinschaft
http://dx.doi.org/10.13039/501100001659We acknowledge support by the Open Access Publication Fund of Humboldt‐Universität zu Berlin.Peer Reviewe
Plasma diagnostics in pulsed laser deposition of GaLaS chalcogenides
International audienceThe aim of this work is to characterize the ejection plume obtained by laser ablation of GaLaS (GLS) samples in order to better understand the ablation phenomena for optimizing the pulsed laser deposition of chalcogenide thin films. The dynamics of the plasma between target and substrate was investigated through time- and space-resolved optical emission spectroscopy. High-resolution optical spectra have been recorded in the UV-VIS range using a 500-mm focal length monochromator and a fast gate ICCD camera. From the space-time evolution of the optical signals, the velocities of various species (including neutrals and ions) have been derived. Using the relative intensity method, the space- and time-evolution of the excitation temperature and electronic density have been determined. A complex behavior of the laser ablation plasma has been revealed
Encapsulated peritoneal sclerosis. Clinical observations
Scopul lucrării. Scleroza peritoneală încapsulată este o boală fibro-inflamatoare cronică a peritoneului, având ca rezultat formarea
unei membrane fibroase groase, care înglobează parțial sau total organele abdominale. Scopul studiului este prezentarea 2 cazuri
de scleroza peritoneală încapsulată.
Caz clinic. Caz clinic nr.1: Pacienta V., 76 ani s-a prezentat la departamentul de urgență cu simptome clinice de ocluzie intestinală,
caracterizate prin crize recurente de obstrucție intestinală acută și subacută.A suportat 8 luni echinococectomie hepatica pentru chist
hidatic hepatic, erupt în cavitatea abdominala. Rezultatele examenului fizic, ecografia și radiografic abdominal au fost în concordanță
cu obstrucția intestinală. Laparotomia a evidențiat o capsulă unica fibroasă, care acoperă ansele intestinale, ficatul, splina, cloazonari
lichidiene peritoneale. Tratamentul chirurgical prin decapsulare completă atestă absenţa planului de delimitare netă între sacul fibros
şi seroasa viscerală si altor leziuni stenozante intestinale. Perioada postoperatorie trenanta. Externată pentru tratament ambulator.
Caz clinic nr. 2: Pacienta N., 17 ani, cu anamneza ginecologică agravată, se intervine chirurgical pentru tumora abdominală, sindrom
ocluziv. Intraoperator se constată formațiune de volum ce include porțiunea terminală a ileonului (80 cm) închistată într-o membrană
unică. S-a practicat decapsularea. Perioada postoperatorie simplă.
Concluzii. Scleroza peritoneală incapsulată reprezintă o entitate clinico-morfologică ce pune reale probleme de diagnostic și tratament,
fiind adesea o descoperire operatorie. Managementul include necesitatea biopsiei peritoneale. Prognosticul rămâne rezervat cu o
mortalitate semnificativă.Aim of study. Encapsulated peritoneal sclerosis is a chronic fibro-inflammatory disease of the peritoneum, resulting in the formation
of a thick fibrous membrane that partially or totally encloses the abdominal organs. The aim is presentation of 2 cases of encapsulated
peritoneal sclerosis.
Clinical case. Clinical case nr. 1: Patient V., 76 years old, presented to the emergency department with clinical symptoms of
intestinal occlusion, characterized by recurrent bouts of acute and subacute intestinal obstruction. She underwent 8-month hepatic
echinococcectomy for a hepatic hydatid cyst, which erupted in the abdominal cavity. The results of physical examination, ultrasound
and abdominal radiography were consistent with intestinal obstruction. Laparotomy revealed a single fibrous capsule, covering the
intestinal loops, liver, spleen, peritoneal fluid cloazonaries. Surgical treatment by complete decapsulation attests to the absence of a
clear demarcation plane between the fibrous sac and the visceral serosa and other intestinal stenosing lesions. Terrible postoperative
period. Discharged for outpatient treatment. Clinical case nr. 2: Patient N., 17 years old, with aggravated gynecological anamnesis,
surgical intervention for abdominal tumor, occlusive syndrome. Intraoperatively, a volume formation is found that includes the terminal
portion of the ileum (80 cm) enclosed in a single membrane. Decapsulation was practiced. Simple postoperative period.
Conclusions. Encapsulated peritoneal sclerosis represents a clinical-morphological entity that poses real diagnostic and treatment
problems, being often an operative discovery. Management includes the need for peritoneal biopsy. The prognosis remains reserved
with significant mortality
First-Tier Array CGH in Clinically Variable Entity Diagnosis: 22q13.3 Deletion Syndrome
Phelan-McDermid (PMS) or 22q13 deletion syndrome (OMIM 606232) is a rare genetic disorder with highly variable clinical presentation. The phenotype includes generalized neonatal hypotonia, developmental delay with intellectual disability and delayed speech, mild dysmorphic features, and autistic behavior. The genetic defects of PMS consist of 22q13.3 deletions or chromosomal structural rearrangements involving SHANK3 gene; the loss of function mutations of SHANK3 gene was reported in a minority of cases. The 22q13.3 deletions vary in size, from 0.2 to over 9 Mb, and, although larger deletions are generally associated with more severe phenotypes, the genotype-phenotype correlations are not clear-cut for all patients. SHANK3 is considered the main candidate gene for the neurologic features of PMS. PMS is a rare disorder, often underdiagnosed. There are no established clinical diagnostic criteria for PMS. The genetic tests typically used are chromosomal microarray and multiplex ligation-dependent probe amplification (MLPA) or fluorescent in situ hybridization (FISH) for copy number analysis of SHANK3 gene; next-generation sequencing (NGS) or Sanger sequencing is used for pathogenic mutation screening of SHANK3. In this chapter, we report three cases with PMS and summarize the clinical and genetic diagnostic approaches of this condition, highlighting the role of chromosomal microarray technology in the identification of rare, but significantly impacting patient’s life, DNA copy number abnormalities
Appendicular mucocele. Clinical case
Scopul lucrării. Mucocelul apendicular este o entitate patologică caracterizată prin dilatarea chistică a apendicelui, datorită secreției
anormale de mucinos apendicular. Prezintă incidența scăzută, secundar afecțiunilor benigne (hiperplazie mucinoasă și chistadenom)
sau maligne (chistadenocarcinom).
Materiale și metode. Am analizat cinci pacienți tratați pentru mucocel apendicular în perioada 2012-2023 în Clinica Chirurgie nr.2,
USMF ,,N.Testemițanu,, cu vârsta cuprinsă între 24-92 de ani și evaluată modalitatea de diagnostic și tratament chirurgical.
Rezultate. Manifestările clinice au fost variate, nespecifice, frecvent au simulat alte afecțiuni chirurgicale abdominale. Examenul
preoperator imagistic, ecografic de rutină şi tomografia computerizată în 3 cazuri au confirmat mucocelul apendicular. Diagnosticul a
fost confirmat intraoperator, volumul intervenției chirurgicale fiind rezolvat individual. Studiul anatomopatologic a pieselor operatorii
a stabilit diagnosticul etiologic și histopatologic. Explorarea intraoperatorie a organelor cavității peritoneale și a bazinului mic a fost
obligatorie în diagnosticul diferențial cu formațiunile chistice ale anexelor uterine și ale organelor cavității abdominale.
Concluzii. Mucocelul apendicular se referă la bolile chirurgicale rare, manifestând un tablou clinic nespecific. Explorarea clinicimagistică, histopatologică minuțioasă a fiecărui pacient, determină corect strategiile chirurgicale.Aim of study. Appendicular mucocele is a pathology characterized by cystic dilatation of the appendix, due to abnormal secretion
of appendicular mucinous. It has low incidence, secondary to benign (mucinous hyperplasia and cystadenoma) or malignant
(cystadenocarcinoma) conditions.
Materials and methods. We analyzed five patients treated for appendicular mucocele in the period 2011-2023 in Surgery Clinic no.2,
USMF,, N. Testemitanu,, aged between 24-92 years and evaluated the method of diagnosis and surgical treatment.
Results. Clinical manifestations were varied, nonspecific, and frequently simulated other abdominal surgical conditions. Preoperative
imaging, routine ultrasound examination and computed tomography in 3 cases confirmed the appendicular mucocele. The diagnosis
was confirmed intraoperatively, the volume of surgical intervention being solved individually. Anatomopathological examination of the
operative parts established the etiological and histopathological diagnosis. Intraoperative exploration of the organs of the peritoneal
cavity and small pelvis was mandatory in differential diagnosis with cystic formations of the uterine appendages and organs of the
abdominal cavity.
Conclusions. Appendicular mucocele refers to rare surgical diseases, manifested by a nonspecific clinical picture. The thorough
clinical – imaging, histopathological exploration of each patient correctly determines surgical strategies
Experimental and Theoretical Studies on the Dynamics of Transient Plasmas Generated by Laser Ablation in Various Temporal Regimes
During the last decade, our groups have performed systematic experimental studies on the characterization of plasma plumes generated by laser ablation in various temporal regimes (ns, ps, fs) on materials ranging from simple metals (Al, Cu, Mn, Ni, In, W, …) to more complex compounds (ceramics, chalcogenide glasses, ferrites). Optical (fast imaging and space- and time-resolved emission spectroscopy) and electrical (mainly Langmuir probe) methods have been applied to experimentally investigate the dynamics of the plasma plume and its constituents. Influence of the target physical (thermodynamic and electrical) parameters on the plasma dynamics has been studied. A mathematical correlation between the local and global plasma parameters and the physical properties of the target was proposed for the first time. Peculiar behaviors like plume splitting or plasma oscillations have been evidenced for high laser fluence ablation in vacuum. Along with results from the literature, our findings provide convincing arguments for the existence of multiple double-layers in the laser ablation plasma plume, in a scenario including two-temperature electrons. New fractal-based theoretical approaches have been developed to qualitatively and quantitatively account for the observed phenomena. The space and time evolution of expansion velocity, particle number, current density and plasma temperature were theoretically investigated
A comprehensive protocol for chemical analysis of flame combustion emissions by secondary ion mass spectrometry
International audienceRATIONALE. Time of flight secondary ion mass spectrometry (ToF-SIMS) is used to provide detailed information on the surface chemical composition of soot. An analytical protocol is proposed and tested on a laboratory flame, and the results are compared with our previous measurements provided by two-step laser mass spectrometry (L2MS). METHODS. This work details: (1) the development of a dedicated apparatus to sample combustion products from atmospheric flames and deposit them on substrates suitable for ToF-SIMS analysis; (2) the choice of the deposition substrate and the material of the sampling line, and their effect on the mass spectra; (3) a method to separate the contributions of soot and condensable gas based on impact deposition, and finally (4) the post-acquisition data processing. RESULTS. Compounds produced during flame combustion are detected on the surface of different deposition substrates and attributed a molecular formula based on mass defect analysis. Silicon and titanium wafers perform similarly, while the surface roughness of glass microfiber filters results in a reduced mass resolution. The mass spectra obtained from the analysis of different locations of the deposits obtained by impaction show characteristic patterns that are attributed to soot/condensable gas. CONCLUSIONS. A working method for the analysis of soot samples and the extraction of useful data from mass spectra is proposed. This protocol should help avoiding common experimental issues like sample contamination, while optimizing the setup performance by maximizing the achievable mass resolution
Mixed Compressive Sensing Back-Projection for SAR Focusing on Geocoded Grid
This article presents a new scheme called 2-D mixed compressive sensing back-projection (CS-BP-2D), for synthetic aperture radar (SAR) imaging on a geocoded grid, in a single measurement vector frame. The back-projection linear operator is derived in matrix form and a patched-based approach is proposed for reducing the dimensions of the dictionary. Spatial compressibility of the radar image is exploited by constructing the sparsity basis using the back-projection focusing framework and fast solving the reconstruction problem through the orthogonal matching pursuit algorithm. An artifact reduction filter inspired by the synthetic point spread function is used in postprocessing. The results are validated for simulated and real-world SAR data. Sentinel-1 C-band raw data in both monostatic and space-borne transmitter/stationary receiver bistatic configurations are tested. We show that CS-BP-2D can focus both monostatic and bistatic SAR images, using fewer measurements than the classical approach, while preserving the amplitude, the phase, and the position of the targets. Furthermore, the SAR image quality is enhanced and also the storage burden is reduced by storing only the recovered complex-valued points and their corresponding locations
Broadband velocity modulation spectroscopy of HfF^+: towards a measurement of the electron electric dipole moment
Precision spectroscopy of trapped HfF^+ will be used in a search for the
permanent electric dipole moment of the electron (eEDM). While this dipole
moment has yet to be observed, various extensions to the standard model of
particle physics (such as supersymmetry) predict values that are close to the
current limit. We present extensive survey spectroscopy of 19 bands covering
nearly 5000 cm^(-1) using both frequency-comb and single-frequency laser
velocity-modulation spectroscopy. We obtain high-precision rovibrational
constants for eight electronic states including those that will be necessary
for state preparation and readout in an actual eEDM experiment.Comment: 13 pages, 7 figures, 3 table
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