Modeling, analysis and control of a variable geometry actuator

A new design of variable geometry force actuator is presented in this paper. Based upon this design, a model is derived which is used for steady-state analysis, as well as controller design in the presence of friction. The controlled actuator model is finally used to evaluate the power consumption under worst case conditions. © 2008 IEEE

Management in de glastuinbouw

Bundeling van artikelen uit de vakpers met veel praktische voorbeelde

Seizures and disturbed brain potassium dynamics in the leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts

OBJECTIVE: Loss of function of the astrocyte-specific protein MLC1 leads to the childhood-onset leukodystrophy "megalencephalic leukoencephalopathy with subcortical cysts" (MLC). Studies on isolated cells show a role for MLC1 in astrocyte volume regulation and suggest that disturbed brain ion and water homeostasis is central to the disease. Excitability of neuronal networks is particularly sensitive to ion and water homeostasis. In line with this, reports of seizures and epilepsy in MLC patients exist. However, systematic assessment and mechanistic understanding of seizures in MLC are lacking. METHODS: We analyzed an MLC patient inventory to study occurrence of seizures in MLC. We used two distinct genetic mouse models of MLC to further study epileptiform activity and seizure threshold through wireless extracellular field potential recordings. Whole-cell patch-clamp recordings and K+-sensitive electrode recordings in mouse brain slices were used to explore the underlying mechanisms of epilepsy in MLC. RESULTS: An early onset of seizures is common in MLC. Similarly, in MLC mice, we uncovered spontaneous epileptiform brain activity and a lowered threshold for induced seizures. At the cellular level, we found that although passive and active properties of individual pyramidal neurons are unchanged, extracellular K+dynamics and neuronal network activity are abnormal in MLC mice. INTERPRETATION: Disturbed astrocyte regulation of ion and water homeostasis in MLC causes hyperexcitability of neuronal networks and seizures. These findings suggest a role for defective astrocyte volume regulation in epilepsy. Ann Neurol 2018;83:636-649

Adult-onset Alexander disease with typical "tadpole" brainstem atrophy and unusual bilateral basal ganglia involvement: a case report and review of the literature

<p>Abstract</p> <p>Background</p> <p>Alexander disease (ALX) is a rare neurological disorder characterized by white matter degeneration and cytoplasmic inclusions in astrocytes called Rosenthal fibers, labeled by antibodies against glial fibrillary acidic protein (GFAP). Three subtypes are distinguished according to age at onset: infantile (under age 2), juvenile (age 2 to 12) and adult (over age 12). Following the identification of heterozygous mutations in <it>GFAP </it>that cause this disease, cases of adult-onset ALX have been increasingly reported.</p> <p>Case Presentation</p> <p>We present a 60-year-old Japanese man with an unremarkable past and no family history of ALX. After head trauma in a traffic accident at the age of 46, his character changed, and dementia and dysarthria developed, but he remained independent. Spastic paresis and dysphagia were observed at age 57 and 59, respectively, and worsened progressively. Neurological examination at the age of 60 revealed dementia, pseudobulbar palsy, left-side predominant spastic tetraparesis, axial rigidity, bradykinesia and gaze-evoked nystagmus. Brain MRI showed tadpole-like atrophy of the brainstem, caused by marked atrophy of the medulla oblongata, cervical spinal cord and midbrain tegmentum, with an intact pontine base. Analysis of the <it>GFAP </it>gene revealed a heterozygous missense mutation, c.827G>T, p.R276L, which was already shown to be pathogenic in a case of pathologically proven hereditary adult-onset ALX.</p> <p>Conclusion</p> <p>The typical tadpole-like appearance of the brainstem is strongly suggestive of adult-onset ALX, and should lead to a genetic investigation of the <it>GFAP </it>gene. The unusual feature of this patient is the symmetrical involvement of the basal ganglia, which is rarely observed in the adult form of the disease. More patients must be examined to confirm, clinically and neuroradiologically, extrapyramidal involvement of the basal ganglia in adult-onset ALX.</p

Velocity Dispersion of Excited H2

We present a study of the high rotational bands (J > 2) of H2 toward 4 early type galactic stars: HD 73882, HD 192639, HD 206267, and HD 207538. In each case, the velocity dispersion - characterized by the spectrum fitting parameter b - increases with the level of excitation, a phenomenon that has previously been detected by the Copernicus and IMAPS observatories. In particular, we show with 4 sigma confidence that for HD 192639 it is not possible to fit all J levels with a single b value, and that higher b values are needed for the higher levels. The amplitude of the line broadening, which can be as high as 10 km s^-1, makes explanations such as inhomogeneous spatial distribution unlikely. We investigate a mechanism in which the broadening is due to the molecules that are rotationally excited through the excess energy acquired after their formation on a grain (H2-formation pumping). We show that different dispersions would be a natural consequence of this mechanism. We note however that such process would require a formation rate 10 times higher then what was inferred from other observations. In view of the difficulty to account for the velocity dispersion as thermal broadening (T would be around 10,000 K), we conclude then that we are most certainly observing some highly turbulent warm layer associated with the cold diffuse cloud. Embedded in a magnetic field, it could be responsible for the high quantities of CH+ measured in the cold neutral medium.Comment: accepted in Ap

Cost-effectiveness of a transitional pharmaceutical care program for patients discharged from the hospital

Background To improve continuity of care at hospital admission and discharge and to decrease medication errors pharmaceutical care programs are developed. This study aims to determine the cost-effectiveness of the COACH program in comparison with usual care from a societal perspective. Methods A controlled clinical trial was performed at the Internal Medicine department of a general teaching hospital. All admitted patients using at least one prescription drug were included. The COACH program consisted of medication reconciliation, patient counselling at discharge, and communication to healthcar

Evaluation of the endoplasmic reticulum-stress response in eIF2B-mutated lymphocytes and lymphoblasts from CACH/VWM patients

<p>Abstract</p> <p>Background</p> <p>Eukaryotic translation initiation factor 2B (eIF2B), a guanine nucleotide exchange factor (GEF) and a key regulator of translation initiation under normal and stress conditions, causes an autosomal recessive leukodystrophy of a wide clinical spectrum. EBV-immortalised lymphocytes (EIL) from eIF2B-mutated patients exhibit a decrease in eIF2B GEF activity. eIF2B-mutated primary fibroblasts have a hyper-induction of activating transcription factor 4 (ATF4) which is involved in the protective unfolded protein response (UPR), also known as the ER-stress response. We tested the hypothesis that EIL from eIF2B-mutated patients also exhibit a heightened ER-stress response.</p> <p>Methods</p> <p>We used thapsigargin as an ER-stress agent and looked at polysomal profiles, rate of protein synthesis, translational activation of <it>ATF4</it>, and transcriptional induction of stress-specific mRNAs (<it>ATF4, CHOP, ASNS, GRP78</it>) in normal and eIF2B-mutated EIL. We also compared the level of stress-specific mRNAs between EIL and primary lymphocytes (PL).</p> <p>Results</p> <p>Despite the low eIF2B GEF activity in the 12 eIF2B-mutated EIL cell lines tested (range 40-70% of normal), these cell lines did not differ from normal EIL in their ATF4-mediated ER-stress response. The absence of hyper-induction of ATF4-mediated ER-stress response in eIF2B-mutated EIL in contrast to primary fibroblasts is not related to their transformation by EBV. Indeed, PL exhibited a higher induction of the stress-specific mRNAs in comparison to EIL, but no hyper-induction of the UPR was noticed in the eIF2B-mutated cell lines in comparison to controls.</p> <p>Conclusions</p> <p>Taken together with work of others, our results demonstrate the absence of a major difference in ER-stress response between controls and eIF2B-mutated cells. Therefore, components of the ER-stress response cannot be used as discriminantory markers in eIF2B-related disorders.</p

Exome sequencing reveals mutated SLC19A3 in patients with an early-infantile, lethal encephalopathy

To accomplish a diagnosis in patients with a rare unclassified disorder is difficult. In this study, we used magnetic resonance imaging pattern recognition analysis to identify patients with the same novel heritable disorder. Whole-exome sequencing was performed to discover the mutated gene. We identified seven patients sharing a previously undescribed magnetic resonance imaging pattern, characterized by initial swelling with T2 hyperintensity of the basal nuclei, thalami, cerebral white matter and cortex, pons and midbrain, followed by rarefaction or cystic degeneration of the white matter and, eventually, by progressive cerebral, cerebellar and brainstem atrophy. All patients developed a severe encephalopathy with rapid deterioration of neurological functions a few weeks after birth, followed by respiratory failure and death. Lactate was elevated in body fluids and on magnetic resonance spectroscopy in most patients. Whole-exome sequencing in a single patient revealed two predicted pathogenic, heterozygous missense mutations in the SLC19A3 gene, encoding the second thiamine transporter. Additional predicted pathogenic mutations and deletions were detected by Sanger sequencing in all six other patients. Pathology of brain tissue of two patients demonstrated severe cerebral atrophy and microscopic brain lesions similar to Leigh's syndrome. Although the localization of SLC19A3 expression in brain was similar in the two investigated patients compared to age-matched control subjects, the intensity of the immunoreactivity was increased. Previously published patients with SLC19A3 mutations have a milder clinical phenotype, no laboratory evidence of mitochondrial dysfunction and more limited lesions on magnetic resonance imaging. In some, cerebral atrophy has been reported. The identification of this new, severe, lethal phenotype characterized by subtotal brain degeneration broadens the phenotypic spectrum of SLC19A3 mutations. Recognition of the associated magnetic resonance imaging pattern allows a fast diagnosis in affected infant