Gender differences in functional connectivity during emotion regulation.

Gender differences in emotion regulation (ER) have been postulated, yet their neural basis remains poorly understood. The goal of this study was to investigate this issue from a functional connectivity (FC) perspective. Utilizing a region of interest (ROI) analysis, we investigated whether men and women (N = 48) differed in their FC pattern while viewing versus regulating negative emotion induced by highly salient pictures, and whether this pattern related to their self-reported negative affect and suppression success. Despite women reporting more negative affect, both genders had comparable suppression success. Moreover, differences emerged between men and women's FC patterns. During the regulation of negative emotion, better suppression in women was associated with stronger FC within a cingulo-opercular network, while men exhibited stronger FC within posterior regions of the ventral attentional network. We conclude that due to their propensity for higher emotional reactivity, women may employ a frontal top-down control network to downregulate negative emotion, while men may redirect attention away from the negative stimulus by using posterior regions of the ventral attention network. The findings may have significant implications for understanding women's vulnerability for developing affective disorders and developing targeted individualized treatment.

Orthorhombic HfO2 with embedded Ge nanoparticles in nonvolatile memories used for the detection of ionizing radiation.

Trilayer memory capacitors of control HfO2/floating gate of Ge nanoparticles in HfO2/tunnel HfO2/Si substrate deposited by magnetron sputtering and subsequently annealed are investigated for the first time for applications in radiation dosimetry. In the floating gate (FG), amorphous Ge nanoparticles (NPs) are arranged in two rows inside the HfO2 matrix. The HfO2 matrix is formed of orthorhombic/tetragonal nanocrystals (NCs). The adjacent thin films to the FG are also formed of orthorhombic/tetragonal HfO2 NCs. This phase is formed during annealing, in samples with thick control HfO2, in the presence of Ge, being induced by the stress. In the rest of the control oxide, HfO2 NCs are monoclinic. Orthorhombic HfO2 has ferroelectric properties and therefore enhances the memory window produced by charge storage in Ge NPs to above 6 V. The high sensitivity of 0.8 mV Gy-1 to α particle irradiation from a 241Am source was measured by monitoring the flatband potential during radiation exposure after electrical writing of the memory.

Dense Ge nanocrystals embedded in TiO2 with exponentially increased photoconduction by field effect.

Si and Ge nanocrystals in oxides are of a large interest for photo-effect applications due to the fine-tuning of the optical bandgap by quantum confinement in nanocrystals. In this work, dense Ge nanocrystals suitable for enhanced photoconduction were fabricated from 60% Ge in TiO2 amorphous layers by low temperature rapid thermal annealing at 550 °C. An exponential increase of the photocurrent with the applied voltage was observed in coplanar structure of Ge nanocrystals composite films deposited on oxidized Si wafers. The behaviour was explained by field effect control of the Fermi level at the Ge nanocrystals-TiO2 layer/substrate interfaces. The blue-shift of the absorption gap from bulk Ge value to 1.14 eV was evidenced in both photocurrent spectra and optical reflection-transmission experiments, in good agreement with quantum confinement induced bandgap broadening in Ge nanocrystal with sizes of about 5 nm as found from HRTEM and XRD investigations. A nonmonotonic spectral dependence of the refractive index is associated to the Ge nanocrystals formation. The nanocrystal morphology is also in good agreement with the Coulomb gap hopping mechanism of T-1/2 -type explaining the temperature dependence of the dark conduction.

Single layer of Ge quantum dots in HfO2 for floating gate memory capacitors.

High performance trilayer memory capacitors with a floating gate of a single layer of Ge quantum dots (QDs) in HfO2 were fabricated using magnetron sputtering followed by rapid thermal annealing (RTA). The layer sequence of the capacitors is gate HfO 2/floating gate of single layer of Ge QDs in HfO 2/tunnel HfO 2/p-Si wafers. Both Ge and HfO2 are nanostructured by RTA at moderate temperatures of 600-700 °C. By nanostructuring at 600 °C, the formation of a single layer of well separated Ge QDs with diameters of 2-3 nm at a density of 4-5 × 1015 m-2 is achieved in the floating gate (intermediate layer). The Ge QDs inside the intermediate layer are arranged in a single layer and are separated from each other by HfO2 nanocrystals (NCs) about 8 nm in diameter with a tetragonal/orthorhombic structure. The Ge QDs in the single layer are located at the crossing of the HfO2 NCs boundaries. In the intermediate layer, besides Ge QDs, a part of the Ge atoms is segregated by RTA at the HfO2 NCs boundaries, while another part of the Ge atoms is present inside the HfO2 lattice stabilizing the tetragonal/orthorhombic structure. The fabricated capacitors show a memory window of 3.8 ± 0.5 V and a capacitance-time characteristic with 14% capacitance decay in the first 3000-4000 s followed by a very slow capacitance decrease extrapolated to 50% after 10 years. This high performance is mainly due to the floating gate of a single layer of well separated Ge QDs in HfO2, distanced from the Si substrate by the tunnel oxide layer with a precise thickness.

Growth, characterization, and transport properties of ternary (Bi1-x Sb x )2Te3 topological insulator layers.

Ternary (Bi1-x Sb x )2Te3 films with an Sb content between 0 and 100% were deposited on a Si(1 1 1) substrate by means of molecular beam epitaxy. X-ray diffraction measurements confirm single crystal growth in all cases. The Sb content is determined by x-ray photoelectron spectroscopy. Consistent values of the Sb content are obtained from Raman spectroscopy. Scanning Raman spectroscopy reveals that the (Bi1-x Sb x )2Te3 layers with an intermediate Sb content show spatial composition inhomogeneities. The observed spectra broadening in angular-resolved photoemission spectroscopy (ARPES) is also attributed to this phenomena. Upon increasing the Sb content from x = 0 to 1 the ARPES measurements show a shift of the Fermi level from the conduction band to the valence band. This shift is also confirmed by corresponding magnetotransport measurements where the conductance changes from n- to p-type. In this transition region, an increase of the resistivity is found, indicating a location of the Fermi level within the band gap region. More detailed measurements in the transition region reveals that the transport takes place in two independent channels. By means of a gate electrode the transport can be changed from n- to p-type, thus allowing a tuning of the Fermi level within the topologically protected surface states.

Study of GeSn based heterostructures: towards optimized group IV MQW LEDs.

We present results on CVD growth and electro-optical characterization of Ge(0.92)Sn(0.08)/Ge p-i-n heterostructure diodes. The suitability of Ge as barriers for direct bandgap GeSn active layers in different LED geometries, such as double heterostructures and multi quantum wells is discussed based on electroluminescence data. Theoretical calculations by effective mass and 6 band k∙p method reveal low barrier heights for this specific structure. Best configurations offer only a maximum barrier height for electrons of about 40 meV at the Γ point at room temperature (e.g. 300 K), evidently insufficient for proper light emitting devices. An alternative solution using SiGeSn as barrier material is introduced, which provides appropriate band alignment for both electrons and holes resulting in efficient confinement in direct bandgap GeSn wells. Finally, epitaxial growth of such a complete SiGeSn/GeSn/SiGeSn double heterostructure including doping is shown.

Orbitofrontal cortex neurofeedback produces lasting changes in contamination anxiety and resting-state connectivity.

Anxiety is a core human emotion but can become pathologically dysregulated. We used functional magnetic resonance imaging (fMRI) neurofeedback (NF) to noninvasively alter patterns of brain connectivity, as measured by resting-state fMRI, and to reduce contamination anxiety. Activity of a region of the orbitofrontal cortex associated with contamination anxiety was measured in real time and provided to subjects with significant but subclinical anxiety as a NF signal, permitting them to learn to modulate the target brain region. NF altered network connectivity of brain regions involved in anxiety regulation: subjects exhibited reduced resting-state connectivity in limbic circuitry and increased connectivity in the dorsolateral prefrontal cortex. NF has been shown to alter brain connectivity in other contexts, but it has been unclear whether these changes persist; critically, we observed changes in connectivity several days after the completion of NF training, demonstrating that such training can lead to lasting modifications of brain functional architecture. Training also increased subjects' control over contamination anxiety several days after the completion of NF training. Changes in resting-state connectivity in the target orbitofrontal region correlated with these improvements in anxiety. Matched subjects undergoing a sham feedback control task showed neither a reorganization of resting-state functional connectivity nor an improvement in anxiety. These data suggest that NF can enable enhanced control over anxiety by persistently reorganizing relevant brain networks and thus support the potential of NF as a clinically useful therapy.

Longer InN phonon lifetimes in nanowires.

We present a Raman scattering study of the anharmonic phonon decay of the [Formula: see text], [Formula: see text] and E1(LO) phonons in InN nanowires over the 80-400 K temperature range. While the temperature-dependent anharmonic decay in the nanowires is similar to that found for bulk InN, the background contribution to the phonon lifetime is strongly reduced as a result of the improved crystalline quality. High-resolution measurements reveal a remarkably long lifetime of the [Formula: see text] mode. From the comparison between the [Formula: see text] frequencies measured in the nanowires with those of the thin film we obtain the deformation potentials for the [Formula: see text] mode.

Properties of uniform diameter InN nanowires obtained under Si doping.

High quality, well-separated, homogeneous sizes and high aspect ratio Si-doped InN nanowires (NWs) were grown by catalyst-free molecular beam epitaxy (MBE) after optimization of the growth conditions. To this end, statistical analysis of NW density and size distribution was performed. The high crystal quality and smooth NW surfaces were observed by high resolution transmission electron microscopy. Spectral photoluminescence has shown the increase of the band filling effect with Si flux, indicating successful n-type doping. A Raman LO scattering mode appears with a pronounced low energy tail, also reported for highly doped InN films.

Selective-area catalyst-free MBE growth of GaN nanowires using a patterned oxide layer.

GaN nanowires (NWs) were grown selectively in holes of a patterned silicon oxide mask, by rf-plasma-assisted molecular beam epitaxy (PAMBE), without any metal catalyst. The oxide was deposited on a thin AlN buffer layer previously grown on a Si(111) substrate. Regular arrays of holes in the oxide layer were obtained using standard e-beam lithography. The selectivity of growth has been studied varying the substrate temperature, gallium beam equivalent pressure and patterning layout. Adjusting the growth parameters, GaN NWs can be selectively grown in the holes of the patterned oxide with complete suppression of the parasitic growth in between the holes. The occupation probability of a hole with a single or multiple NWs depends strongly on its diameter. The selectively grown GaN NWs have one common crystallographic orientation with respect to the Si(111) substrate via the AlN buffer layer, as proven by x-ray diffraction (XRD) measurements. Based on the experimental data, we present a schematic model of the GaN NW formation in which a GaN pedestal is initially grown in the hole.

Enhanced light scattering of the forbidden longitudinal optical phonon mode studied by micro-Raman spectroscopy on single InN nanowires.

In the literature, there are controversies on the interpretation of the appearance in InN Raman spectra of a strong scattering peak in the energy region of the unscreened longitudinal optical (LO) phonons, although a shift caused by the phonon-plasmon interaction is expected for the high conductance observed in this material. Most measurements on light scattering are performed on ensembles of InN nanowires (NWs). However, it is important to investigate the behavior of individual nanowires and here we report on micro-Raman measurements on single nanowires. When changing the polarization direction of the incident light from parallel to perpendicular to the wire, the expected reduction of the Raman scattering was observed for transversal optical (TO) and E(2) phonon scattering modes, while a strong symmetry-forbidden LO mode was observed independently on the laser polarization direction. Single Mg- and Si-doped crystalline InN nanowires were also investigated. Magnesium doping results in a sharpening of the Raman peaks, while silicon doping leads to an asymmetric broadening of the LO peak. The results can be explained based on the influence of the high electron concentration with a strong contribution of the surface accumulation layer and the associated internal electric field.

Investigation on localized states in GaN nanowires.

GaN nanowires with diameters ranging between 50 and 500 nm were investigated by electrical and photoinduced current techniques to determine the influence of their size on the opto-electronic behavior of nanodevices. The conductivity, photoconductivity, and persistent photoconductivity behavior of GaN nanowires are observed to strongly depend on the wire diameter. In particular, by spectral photoconductivity measurements, three main sub-band-gap optoelectronic transitions were detected, ascribed to the localized states giving rise to the characteristic blue, green, and yellow bands of GaN. Photoconductivity with below-band-gap excitation varies orders of magnitude with the wire diameter, similarly to that observed for near-band-edge excitation. Moreover, yellow-band-related signal shows a superlinear behavior with respect to the band-edge signal, offering new information for the modeling of the carrier recombination mechanism along the nanowires. The photoconductivity results agree well with a model which takes into account a uniform distribution of the localized states inside the wire and their direct recombination with the electrons in the conduction band.

[Hepatic hydatid cyst in minimally invasive surgery]. / Chistul hidatic hepatic în chirurgia miniinvaziva.

The hydatid cyst, especially the hepatic one has come to be considered, for some years ago, in the Mediterranean and Black Sea's countries. The distribution area of this disease has a common feature beyond the geographical area once the agricultural-economic characteristics. A disease with a therapeutic visa, especially a digestive one with highly recognized invasion can be treated using laparoscopic treatment for most of the cases, excepting cysto-digestive sutures as therapeutical solutions. That is why we inform you about some of our results, the therapeutical adapted solutions and the issued complications.

Gastric liposarcoma. A case report.

Gastric localization of a liposarcoma is exceptional. A 67 year old patient with repeated hematemesis was found to have an ulcer on the dorsal wall of the antrum on radiology. Surgery revealed an ulcerated tumour, 5 X 2 X 1.5 cm, involving the tunica muscularis up to the serosa. Histologic examination showed a liposarcoma with intricate myxomatous zones, round cells, pleomorphous clearly differentiated lipoblastic aspects, and haemorrhagic areas.