582 research outputs found
Optimal edge termination for high oxide reliability aiming 10kV SiC n-IGBTs
The edge termination design strongly affects the ability of a power device to support the desired voltage and its reliable operation. In this paper we present three appropriate termination designs for 10kV n-IGBTs which achieve the desired blocking requirement without the need for deep and expensive implantations. Thus, they improve the ability to fabricate, minimise the cost and reduce the lattice damage due to the high implantation energy. The edge terminations presented are optimised both for achieving the widest immunity to dopant activation and to minimise the electric field at the oxide. Thus, they ensure the long-term reliability of the device. This work has shown that the optimum design for blocking voltage and widest dose window does not necessarily give the best design for reliability. Further, it has been shown that Hybrid Junction Termination Extension structure with Space Modulated Floating Field Rings can give the best result of very high termination efficiency, as high as 99%, the widest doping variation immunity and the lowest electric field in the oxide
Resting state alpha oscillatory activity is a valid and reliable marker of schizotypy
Schizophrenia is among the most debilitating neuropsychiatric disorders. However, clear neurophysiological markers that would identify at-risk individuals represent still an unknown. The aim of this study was to investigate possible alterations in the resting alpha oscillatory activity in normal population high on schizotypy trait, a physiological condition known to be severely altered in patients with schizophrenia. Direct comparison of resting-state EEG oscillatory activity between Low and High Schizotypy Group (LSG and HSG) has revealed a clear right hemisphere alteration in alpha activity of the HSG. Specifically, HSG shows a significant slowing down of right hemisphere posterior alpha frequency and an altered distribution of its amplitude, with a tendency towards a reduction in the right hemisphere in comparison to LSG. Furthermore, altered and reduced connectivity in the right fronto-parietal network within the alpha range was found in the HSG. Crucially, a trained pattern classifier based on these indices of alpha activity was able to successfully differentiate HSG from LSG on tested participants further confirming the specific importance of right hemispheric alpha activity and intrahemispheric functional connectivity. By combining alpha activity and connectivity measures with a machine learning predictive model optimized in a nested stratified cross-validation loop, current research offers a promising clinical tool able to identify individuals at-risk of developing psychosis (i.e., high schizotypy individuals)
The Role of Alpha Oscillations among the Main Neuropsychiatric Disorders in the Adult and Developing Human Brain: Evidence from the Last 10 Years of Research
Alpha oscillations (7–13 Hz) are the dominant rhythm in both the resting and active brain.
Accordingly, translational research has provided evidence for the involvement of aberrant alpha activ-
ity in the onset of symptomatological features underlying syndromes such as autism, schizophrenia,
major depression, and Attention Deficit and Hyperactivity Disorder (ADHD). However, findings on
the matter are difficult to reconcile due to the variety of paradigms, analyses, and clinical phenotypes
at play, not to mention recent technical and methodological advances in this domain. Herein, we seek
to address this issue by reviewing the literature gathered on this topic over the last ten years. For each
neuropsychiatric disorder, a dedicated section will be provided, containing a concise account of the
current models proposing characteristic alterations of alpha rhythms as a core mechanism to trigger
the associated symptomatology, as well as a summary of the most relevant studies and scientific con-
tributions issued throughout the last decade. We conclude with some advice and recommendations
that might improve future inquiries within this field
Priprava i evaluacija hidrogela s diazepamom za rektalnu primjenu
Diazepam (DZP) has become a commonly used drug for treatment of acute repetitive epileptic seizures and febrile convulsions in children. Considering the advantages of rectal administration of DZP, the objective of our study was to formulate and evaluate rectal hydrogels containing DZP as a drug substance in combination with suitable co-solvents and preservatives. Prepared HPMC (hydroxypropyl methylcellulose) hydrogels containing different concentrations of DZP (2, 4 and 6 mg mL-1) manifested good quality in respect to physico-chemical parameters (pH value, drug content, ingredients content and viscosity), antimicrobial efficiency and microbiological quality. Under the proposed HPLC conditions, satisfactory separation of DZP and the preservatives used was achieved. In vitro release studies have shown that the total amount of DZP was released in a period of 3 h. Prepared formulations were stable for four months at 26 oC (ambient temperature characteristic of the 2nd climate zone).Diazepam (DZP) je ljekovita tvar koja se upotrebljava u terapiji akutnih epileptičkih napada i febrilnih konvulzija u djece. U radu je opisana priprava i evaluacija hidrogela za rektalnu primjenu s diazepamom i odgovarajućim pomoćnim tvarima i konzervansima.
Pripravci su sadržavali različite koncentracije DZP (2, 4 i 6 mg mL-1). Njihova fizičko-kemijska svojstva (pH vrijednost, sadržaj ljekovite i pomoćnih tvari, viskoznost), antimikrobna učinkovitost i mikrobiološka čistoća bili su zadovoljavajući. Razvijena je HPLC metoda kojom je postignuta separcija DZP i konzervansa. In vitro ispitivanja su pokazala da se cjelokupna količina DZP oslobodi tijekom 3 h. Pripravci su bili stabilni 4 mjeseca na temperaturi 26 C (sobna temperatura karakteristična za 2. klimatsku zonu)
Facile Stereoselective Reduction of Prochiral Ketones by using an F <sub>420</sub>-dependent alcohol dehydrogenase
Effective procedures for the synthesis of optically pure alcohols are highly valuable. A commonly employed method involves the biocatalytic reduction of prochiral ketones. This is typically achieved by using nicotinamide cofactor-dependent reductases. In this work, we demonstrate that a rather unexplored class of enzymes can also be used for this. We used an F420-dependent alcohol dehydrogenase (ADF) from Methanoculleus thermophilicus that was found to reduce various ketones to enantiopure alcohols. The respective (S) alcohols were obtained in excellent enantiopurity (>99 % ee). Furthermore, we discovered that the deazaflavoenzyme can be used as a self-sufficient system by merely using a sacrificial cosubstrate (isopropanol) and a catalytic amount of cofactor F420 or the unnatural cofactor FOP to achieve full conversion. This study reveals that deazaflavoenzymes complement the biocatalytic toolbox for enantioselective ketone reductions
Cancer and systemic inflammation: treat the tumour and treat the host
Determinants of cancer progression and survival are multifactorial and host responses are increasingly appreciated to have a major role. Indeed, the development and maintenance of a systemic inflammatory response has been consistently observed to confer poorer outcome, in both early and advanced stage disease. For patients, cancer-associated symptoms are of particular importance resulting in a marked impact on day-to-day quality of life and are also associated with poorer outcome. These symptoms are now recognised to cluster with one another with anorexia, weight loss and physical function forming a recognised cluster whereas fatigue, pain and depression forming another. Importantly, it has become apparent that these symptom clusters are associated with presence of a systemic inflammatory response in the patient with cancer. Given the understanding of the above, there is now a need to intervene to moderate systemic inflammatory responses, where present. In this context the rationale for therapeutic intervention using nonselective anti-inflammatory agents is clear and compelling and likely to become a part of routine clinical practice in the near future. The published literature on therapeutic intervention using anti-inflammatory agents for cancer-associated symptoms was reviewed. There are important parallels with the development of useful treatments for the systemic inflammatory response in patients with rheumatological disease and cardiovascular disease
Approaching boiling point stability of an alcohol dehydrogenase through computationally-guided enzyme engineering
Enzyme instability is an important limitation for the investigation and application of enzymes. Therefore, methods to rapidly and effectively improve enzyme stability are highly appealing. In this study we applied a computational method (FRESCO) to guide the engineering of an alcohol dehydrogenase. Of the 177 selected mutations, 25 mutations brought about a significant increase in apparent melting temperature (ΔTm ≥ +3 °C). By combining mutations, a 10-fold mutant was generated with a Tm of 94 °C (+51 °C relative to wildtype), almost reaching water's boiling point, and the highest increase with FRESCO to date. The 10-fold mutant's structure was elucidated, which enabled the identification of an activity-impairing mutation. After reverting this mutation, the enzyme showed no loss in activity compared to wildtype, while displaying a Tm of 88 °C (+45 °C relative to wildtype). This work demonstrates the value of enzyme stabilization through computational library design
Assessment of the Trophic Status by Monitoring of Reservoir’s Water Quality
Continuous long-term monitoring of aquatic systems is important for understanding their complete
evolution in order to monitor changes in the trophic status and water quality. The continuous
monitoring during a period of 20 years, by sampling once a month at two locations, the water
quality of reservoir “Grlište”, which is used for the water supplying town Zaječar (Eastern Serbia),
is observed and developmental stages in the life of the reservoir were determinated. It
should be noted that the obtained results were used also in the purpose of finding a cause of cyanobacteria
bloom, as a consequence of algal production. Limiting factors of algal production usually
were nitrogen and phosphorus, however, in this study, obtained results of subtraction between
trophic state index, calculated through total chlorophyll a (TSIChl-a) and trophic state index, calculated
through total phosphorus (TSITP), indicated that limiting factor of algal production was light.
On the basis of the concentrations of dissolved oxygen (DO), total phosphorus (TP) and chlorophyll
a (Chl-a) in the surface and in the bottom, it was concluded that the reservoir passed through
four development phases during the examined period. Results of long-term monitoring showed
that in the first years after the formation of the reservoir, the highest trophicity was detected (hypereutrophic
status), but later the reservoir mostly maintained eutrophic status
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