Расчет потерь давления воздуха в горных выработках с учетом равномерных и неравномерных утечек

Охарактеризовано метод розрахунку втрат тиску повітря у гірничих виробках за наявності витоків (притоків), який може бути використано під час проектування системи провітрювання шахти з метою вибору засобів місцевого керування повітряних потоків, розрахунку конфігурації ліній витоку у виробленому просторі та при оцінці зміни витоків у аварійній ситуації і розробці методів керування ними.The method of calculation losses of pressure of air in the mining workings at presence of leakages (inflows), which can be used for planning of the ventilation system of mine with the purpose of choice facilities of the local control of air blast, calculation of configuration lines of leakages in the worked out goaf and at estimation change of leakages in an emergency situation and development methods of control by them

Neuroimaging in anxiety disorders

Neuroimaging studies have gained increasing importance in validating neurobiological network hypotheses for anxiety disorders. Functional imaging procedures and radioligand binding studies in healthy subjects and in patients with anxiety disorders provide growing evidence of the existence of a complex anxiety network, including limbic, brainstem, temporal, and prefrontal cortical regions. Obviously, “normal anxiety” does not equal “pathological anxiety” although many phenomena are evident in healthy subjects, however to a lower extent. Differential effects of distinct brain regions and lateralization phenomena in different anxiety disorders are mentioned. An overview of neuroimaging investigations in anxiety disorders is given after a brief summary of results from healthy volunteers. Concluding implications for future research are made by the authors

Outcome and antiepileptic drug policies after childhood epilepsy surgery in children

Epilepsy is defined as a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures. Of patients with newly diagnosed epilepsy, 70–80% respond well to medical treatment, while 20–30% develop intractable epilepsy. For intractable epilepsy patients with a clearly localized, or at least lateralized epileptic focus, epilepsy surgery is a valuable treatment option. The aims of epilepsy surgery are to achieve postoperative seizure freedom, stop the developmental regression caused by intractable seizures, and to decrease the adverse effects of antiepileptic drugs (AEDs) on cognition through withdrawal of AEDs. This thesis focusses on functional outcome, seizure outcome and antiepileptic drug policies after childhood epilepsy surgery. We first studied if indications for epilepsy surgery changed over the years and if indications for surgery had broadened. We found that although more complex cases were operated on over time and medication was withdrawn earlier after surgery, success rates at two years remained stable. Secondly, we assessed integrity of the brain by studying underlying etiology, MR imaging and EEG recordings that were part of clinical investigations in children, in relation to their motor, cognitive and seizure outcome. We found etiology to be an important predictor for functional outcome. Children with developmental etiology more often lost hand function postoperatively and showed less improvement in gross motor function compared to others. Loss of hand function could be predicted based on corticospinal tract damage on preoperative MRI. Furthermore, unambiguous contralateral MRI abnormalities were associated with seizure recurrence, severe mental delay, and lack of cognitive improvement after hemispherectomy, while contralateral EEG abnormalities did not negatively influence postsurgical outcome. Nevertheless, contralateral MRI abnormalities should not be a contra-indication for surgery, as even the ‘failures’ do better than they would have done without surgery.Thirdly, we studied if early discontinuation of AEDs after surgery would be safe, and whether it would improve functional recovery in terms of cognition. In our large European TimeToStop (TTS) cohort of 766 children, we studied AED withdrawal policies and found that, although shorter time intervals to both start and completion of AED withdrawal slightly increased the risk for seizure recurrences, early AED withdrawal did not affect long-term seizure outcome. It might unmask incomplete surgical success sooner, identifying children who need continuous drug treatment and preventing unnecessary continuation of AEDs in others. Furthermore we found that complete AED withdrawal improved psychomotor speed 24 months after surgery in 57 Dutch children, and that start of AED withdrawal, number of AEDs reduced, and complete AED withdrawal were all associated with improved postoperative IQ scores and gain in IQ, independent of other determinants of cognitive outcome in a subgroup of the TTS cohort of 301 patients. To confirm our non-experimental findings prospectively, we are close to starting the randomized TimeToStop trial, in which we will investigate whether early AED withdrawal improves cognitive function in terms of attention and intelligence, quality of life and behaviour, and aim to confirm safety of early reduction, in terms of seizure recurrences, eventual seizure freedom and “seizure and AED freedom”

Individualized prediction of seizure relapse and outcomes following antiepileptic drug withdrawal after pediatric epilepsy surgery

The objective of this study was to create a clinically useful tool for individualized prediction of seizure outcomes following antiepileptic drug withdrawal after pediatric epilepsy surgery. We used data from the European retrospective TimeToStop study, which included 766 children from 15 centers, to perform a proportional hazard regression analysis. The 2 outcome measures were seizure recurrence and seizure freedom in the last year of follow-up. Prognostic factors were identified through systematic review of the literature. The strongest predictors for each outcome were selected through backward selection, after which nomograms were created. The final models included 3 to 5 factors per model. Discrimination in terms of adjusted concordance statistic was 0.68 (95% confidence interval [CI] 0.67-0.69) for predicting seizure recurrence and 0.73 (95% CI 0.72-0.75) for predicting eventual seizure freedom. An online prediction tool is provided on www.epilepsypredictiontools.info/ttswithdrawal. The presented models can improve counseling of patients and parents regarding postoperative antiepileptic drug policies, by estimating individualized risks of seizure recurrence and eventual outcome

Etiology-specific differences in motor function after hemispherectomy

Item does not contain fulltextPrediction of functional motor outcome after hemispherectomy is difficult due to the heterogeneity of motor outcomes observed. We hypothesize that this might be related to differences in plasticity during the onset of the underlying epileptogenic disorder or lesion and try to identify predictors of motor outcome after hemispherectomy. Thirty-five children with different etiologies (developmental, stable acquired or progressive) underwent functional hemispherectomy and motor function assessment before hemispherectomy and 24 months after hemispherectomy. Preoperatively, children with developmental etiologies performed better in terms of distal arm strength and hand function, but not on gross motor function tests. Postoperatively, the three etiology groups performed equally poor in muscle strength and hand function, but gross motor function improved in those with acquired and progressive etiologies. Loss of voluntary hand function and distal arm strength after surgery was associated with etiology, intact insular cortex and intact structural integrity of the ipsilesional corticospinal tract on presurgical MRI scans. In conclusion, postoperative motor function can be predicted more precisely based on etiology and on preoperative MRI. Children with developmental etiology more often lose distal arm strength and hand function and show less improvement in gross motor function, compared to those with acquired pathology