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Residual depressive symptoms are generally documented as a risk factor for recurrence. In the absence of a specific instrument for the assessment of residual symptoms, a new 25-item Depression Residual Symptom Scale (DRSS) was elaborated and tested for recurrence prediction over a 1-year follow-up.
Sampling and methods
Fifty-nine patients in remission after a major depressive episode (MDE) were recruited in two centres. They were assessed with the DRSS and the Montgomery-Asberg Depression Rating Scale (MADRS) at inclusion and followed for 1 year according to a seminaturalistic design. The DRSS included specific depressive symptoms and subjective symptoms of vulnerability, lack of return to usual self and premorbid level of functioning.
Severity of residual symptoms was not significantly associated with increased risk of recurrence. However, DRSS score was significantly higher among patients with three or more episodes than one to two episodes. Number of previous episodes and treatment interruption were not identified as significant predictors of recurrence.
The proposed instrument is not predictive of depressive recurrence, but is sensitive to increased perception of vulnerability associated with consecutive episodes. Limitations include small sample size, seminaturalistic design (no standardisation of treatment) and content of the instrument.
The present open study investigates the feasibility of Mindfulness-based cognitive therapy (MBCT) in groups solely composed of bipolar patients of various subtypes. MBCT has been mostly evaluated with remitted unipolar depressed patients and little is known about this treatment in bipolar disorder.
Bipolar outpatients (type I, II and NOS) were included and evaluated for depressive and hypomanic symptoms, as well as mindfulness skills before and after MBCT. Patients’ expectations before the program, perceived benefit after completion and frequency of mindfulness practice were also recorded.
Of 23 included patients, 15 attended at least four MBCT sessions. Most participants reported having durably, moderately to very much benefited from the program, although mindfulness practice decreased over time. Whereas no significant increase of mindfulness skills was detected during the trial, change of mindfulness skills was significantly associated with change of depressive symptoms between pre- and post-MBCT assessments.
MBCT is feasible and well perceived among bipolar patients. Larger and randomized controlled studies are required to further evaluate its efficacy, in particular regarding depressive and (hypo)manic relapse prevention. The mediating role of mindfulness on clinical outcome needs further examination and efforts should be provided to enhance the persistence of meditation practice with time.
Children of patients with substance use disorders (SUD) are at high risk for mental disorders. The effects of specific SUD in both parents on the risk of psychopathology in offspring have hardly been studied.
To gain a better understanding of the morbid risk of these children.
To assess, 1) the associations between alcohol dependence (AD) or heroin dependence (HD) in patients and psychopathology in their children; 2) the morbid risk conferred by having a second parent with SUD.
The sample included 276 children aged from 6 to 17.9 years (mean age = 11.5): 23 children of 15 patients with HD, 101 offspring of 50 patients with AD, 152 children of 81 orthopedic patients (controls) and 158 biological co-parents of the children. Subjects were interviewed by psychologists blind to patient diagnoses, using a semi-structured diagnostic interview.
1) Children of HD or AD patients had largely elevated rates of recurrent major depressive disorder and children of HD patients were also at an increased risk for ADHD and SUD; 2) There were interactions between drug disorders and alcohol disorders in both parents to increase the risk of early SUD in offspring.
The early manifestations of mental disorders in children of SUD patients emphasize the need for prompt identification and treatment of these disorders. The involvement of co-parental disorders in the development of offspring psychopathology highlights the need to pay clinical attention not only to the patient, but also to the co-parent in order to optimize prevention in offspring.
Previous functional magnetic resonance imaging studies in bipolar disorder (BD) have evidenced changes in functional connectivity (FC) in brain areas associated with emotion processing, but how these changes vary with mood state and specific clinical symptoms is not fully understood.
We investigated resting-state FC between a priori regions of interest (ROIs) from the default-mode network and key structures for emotion processing and regulation in 27 BD patients and 27 matched healthy controls. We further compared connectivity patterns in subgroups of 15 euthymic and 12 non-euthymic patients and tested for correlations of the connectivity strength with measures of mood, anxiety, and rumination tendency. No correction for multiple comparisons was applied given the small population sample and pre-defined target ROIs.
Overall, regardless of mood state, BD patients exhibited increased FC of the left amygdala with left sgACC and PCC, relative to controls. In addition, non-euthymic BD patients showed distinctive decrease in FC between right amygdala and sgACC, whereas euthymic patients showed lower FC between PCC and sgACC. Euthymic patients also displayed increased FC between sgACC and right VLPFC. The sgACC–PCC and sgACC–left amygdala connections were modulated by rumination tendency in non-euthymic patients, whereas the sgACC-VLPFC connection was modulated by both the current mood and tendency to ruminate.
Our results suggest that sgACC-amygdala coupling is critically affected during mood episodes, and that FC of sgACC play a pivotal role in mood normalization through its interactions with the VLPFC and PCC. However, these preliminary findings require replication with larger samples of patients.
A review is presented of Synchrotron X-ray Topography and KOH etching studies carried out on n type 4H-SiC offcut substrates before and after homo-epitaxial growth to study defect replication and strain relaxation processes and identify the nucleation sources of both interfacial dislocations (IDs) and half-loop arrays (HLAs) which are known to have a deleterious effect on device performance. We show that these types of defects can nucleate during epilayer growth from: (1) short segments of edge oriented basal plane dislocations (BPDs) in the substrate which are drawn by glide into the epilayer; and (2) segments of half loops of BPD that are attached to the substrate surface prior to growth which also glide into the epilayer. It is shown that the initial motion of the short edge oriented BPD segments that are drawn from the substrate into the epilayer is caused by thermal stress resulting from radial temperature gradients experienced by the wafer whilst in the epi-chamber. This same stress also causes the initial glide of the surface half-loop into the epilayer and through the advancing epilayer surface. These mobile BPD segments provide screw oriented segments that pierce the advancing epilayer surface that initially replicate as the crystal grows. Once critical thickness is reached, according to the Mathews-Blakeslee model , these screw segments glide sideways under the action of the mismatch stress leaving IDs and HLAs in their wake. The origin of the mismatch stress is shown to be associated with lattice parameter differences at the growth temperature, arising from the differences in doping concentration between substrate and epilayer.
Energy efficiency in BOF process is related to hot metal and scrap
ratio and thus to production capacity potential and specific CO2
emissions. A thermal balance in the fume system, using a selected
metrology, can be calculated dynamically and provides a valuable
tool for investigating the process parameters that are relevant for
optimizing and controlling energy efficiency. The method and first
results are presented.
High power RF device performance
decreases as operation temperature increases (e.g. decreasing electron
mobility affects cut-off frequencies and degrades device reliability).
Therefore determination of device temperature is a key issue for device
topology optimisation. In this work the temperature variation of AlGaN/GaN
high-electron-mobility transistors grown either on silicon or sapphire
substrate under bias operation was measured by micro Raman scattering
spectroscopy. Temperature measurements up to power dissipation of 16 W for
4 mm development devices were carried out and a peak temperature of 650 K was
determined. The difference of thermal resistance for similar devices grown
on the two different substrates was assessed. The thermal resistances of
different device topologies were compared to optimise the component design.
The high power RF device performance decreases as the operation
temperature increases (e.g. fall of electron mobility impacting
the cut-off frequencies and degradation of device reliability).
Therefore the determination of device temperature is a key issue
for device topology optimisation. In this work the temperature
variation of AlGaN/GaN high-electron-mobility transistors grown
either on silicon or sapphire substrates under bias operation was
measured by micro Raman scattering spectroscopy. The differences
in thermal resistance for similar devices grown on the two
different substrates were assessed. The thermal resistances of
different device topologies were compared in order to optimise
the component design. The temperature measurement across the gate
and along the component fingers were made to quantify the thermal
gradient of the device. Temperature measurement up to a power
dissipation of 16 W for a 4 mm development device was carried out
and the peak temperature of 650 K was determined.
The high power RF device performance decreases as operation
temperature increases (e.g. fall of electron mobility impacting the cut-off frequencies
and degradation of device reliability). Therefore the determination of device
temperature is a key issue for device topology optimisation. This work presents the
comparison between pulsed I-V at different temperature and DC measurements of
AlGaN/GaN HEMTs grown on two different substrates: sapphire and silicon. This
technique allows the determination of mean channel temperature and the device
thermal resistance. The thermal resistance is a classical way to define the average
channel temperature as a function of the dissipated power. In this work the thermal
resistance ratio of the HEMT grown on sapphire compared to the one grown on silicon
is found to be 1.7 instead of 3 as expected from straightforward thermal conductivity
ratio. This lower difference is clearly attributed to the contribution of the GaN buffer
This paper reports on the LP-MOCVD growth optimisation of GaAlN/GaN heterostructures grown on Silicon Carbide substrates for HEMT applications, and on the first device performances obtained with these structures. The critical impact of some growth parameters on the physical properties of the GaAlN/GaN epilayers has been identified and studied using High Resolution X-Ray diffraction (HR-XRD), AFM, C-V and sonogauge measurements. The SiC substrate surface preparation (both ex-situ and in-situ) and the nucleation layer growth conditions (growth temperature, thickness, composition and strain) have been found to be key steps of the GaAlN/GaN/SiC growth process. SiC substrates from different suppliers have been evaluated and their influence on the physical properties of the GaAlN/GaN HEMT structures investigated. Static characteristics of the devices such as maximum drain current Idss or pinch-off voltage have been correlated with the nucleation layer composition of the HEMT structure and the defect density of the SiC substrate. First devices measured at 10 GHz using a load pull system exhibited CW output power in excess of 2.8 W/mm for a gate length of 0.5 μm. Under static measurements, we found an Idss around 1 A/mm and a pinch-off voltage of –5 V.