Applications of an electrostatic high-voltage tether to radiation belt remediation

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, June 2007.Includes bibliographical references (leaf 69).A computational algorithm is developed and executed to calculate the rate of depletion of magnetospheric ions by an electrostatic tether at various altitudes. This computation relies upon past studies in the OML regime of charged tethers to determine the deflection angles incurred upon incoming ions at any given incident velocity. Calculated depletion rates are used to computationally estimate the time required to deplete a given range of the magnetosphere.by Christopher F. Zeineh.S.M

The Arbitrary Dismissal of the Worker In Light of the Conflicting rulings of the Palestinian Court of Cassation (PCC)

Palestinian Court of Cassation (PCC). The focus has been, in particular, on the arbitrary dismissal from wok enshrined in the Palestinian Labor Law No. (7) of 2000. Although the rulings issued by the PCC must be uniform and harmonious, so that they can be followed by the appellate courts, despite the reversal of a principle established in a previous ruling issued by the Court of Cassation requires a general assembly of this Court to convene to decide on that return, but we found contradictions in many of the judgments passed by the Court, in several issues related to the subject of arbitrary dismissal. These provisions were contradictory with regard to the amount of compensation for arbitrary dismissal that the dismissed worker is entitled to, as well as contradictory regarding the effect of failure to notify the Ministry of Labor on whether or not arbitrary dismissal is considered. It also contradicted the issue of the burden of proof of arbitrary dismissal, and whether this burden falls on shoulders of the worker or the employer, and also contradicted with regard to the requirement for a one-year period to elapse on the worker\u27s work, for his entitlement to compensation for arbitrary dismissal, and finally, it contradicted the permissibility of terminating the worker\u27s services upon reaching the age of sixty years. In this research, the researcher reviews these contradictory provisions, and expresses his opinion on that contradiction, and in the provisions closest to the texts of the Labor Law and the intention of the legislator, and an examination is made on how to remove and eliminate that contradiction. تناول هذا البحث تناقض أحكام محكمة النقض الفلسطينية في موضوع الفصل التعسفي المنصوص عليه في قانون العمل الفلسطيني رقم (7) لسنة 2000 مع أن الأحكام الصادرة عن محكمة النقض يجب أن تكون موحدة ومتناغمة حتى يمكن اتباعها من قبل المحاكم الاستئنافية، ومع أن الرجوع عن مبدأ مقرر في حكم سابق صادر عن محكمة النقض يتطلّب عقد اجتماع هيئة عامة لهذه المحكمة للبت في ذلك الرجوع، إلا أننا وجدنا تضاربًا وتناقضًا في العديد من الأحكام الصادرة عن محكمة النقض، في عدة مسائل متصلة بموضوع الفصل التعسفي. فقد تناقضت تلك الأحكام فيما يتعلق بشأن مقدار تعويض الفصل التعسفي الذي يستحقه العامل المفصول، وتناقضت أيضًا بشأن تأثير التخلف عن إشعار وزارة العمل على اعتبار الفصل التعسفي من عدمه، وتناقضت كذلك في مسألة عبء إثبات الفصل التعسفي، وما إذا كان هذا العبء يقع على العامل أم صاحب العمل، وتناقضت أيضًا فيما يتعلق باشتراط مضي مدة سنة على عمل العامل لاستحقاقه تعويض الفصل التعسفي، وأخيرًا تناقضت بشأن جواز إنهاء خدمات العامل ببلوغه سن الستين عامًا أوعدم جواز ذلك. وقد استعرضنا في هذا البحث تلك الأحكام المتناقضة، وأبدينا رأينا في ذلك التناقض، وفي الأحكام الأقرب إلى نصوص قانون العمل ولمقصد المشرع، وفي كيفية إزالة ذلك التناقض ورفعه

Efficaciousness of low affinity compared to high affinity TSPO ligands in the inhibition of hypoxic mitochondrial cellular damage induced by cobalt chloride in human lung H1299 cells

The 18 kDa translocator protein (TSPO) plays an important role in apoptotic cell death, including apoptosis induced by the hypoxia mimicking agent cobalt chloride (CoCl2). In this study, the protective effects of a high (CB86; Ki = 1.6 nM) and a low (CB204; Ki = 117.7 nM) affinity TSPO ligands were investigated in H1299 lung cancer cell line exposed to CoCl2. The lung cell line H1299 was chosen in the present study since they express TSPO and able to undergo programmed cell death. The examined cell death markers included: ATP synthase reversal, reactive oxygen species (ROS) generation, mitochondrial membrane potential (D m) depolarization, cellular toxicity, and cellular viability. Pretreatment of the cells with the low affinity ligand CB204 at a concentration of 100 μM suppressed significantly (p < 0.05 for all) CoCl2-induced cellular cytotoxicity (100%), ATP synthase reversal (67%), ROS generation (82%), D m depolarization (100%), reduction in cellular density (97%), and also increased cell viability (85%). Furthermore, the low affinity TSPO ligand CB204, was harmless when given by itself at 100 μM. In contrast, the high affinity ligand (CB86) was significantly effective only in the prevention of CoCl2-induced ROS generation (39%, p < 0.001), and showed significant cytotoxic effects when given alone at 100 μM, as reflected in alterations in ADP/ATP ratio, oxidative stress, mitochondrial membrane potential depolarization and cell death. It appears that similar to previous studies on brain-derived cells, the relatively low affinity for the TSPO target enhances the potency of TSPO ligands in the protection from hypoxic cell death. Moreover, the high affinity TSPO ligand CB86, but not the low affinity ligand CB204, was lethal to the lung cells at high concentration (100 μM). The low affinity TSPO ligand CB204 may be a candidate for the treatment of pulmonary diseases related to hypoxia, such as pulmonary ischemia and chronic obstructive pulmonary disease COPD

Toward more accurate and generalizable brain deformation estimators for traumatic brain injury detection with unsupervised domain adaptation

Machine learning head models (MLHMs) are developed to estimate brain deformation for early detection of traumatic brain injury (TBI). However, the overfitting to simulated impacts and the lack of generalizability caused by distributional shift of different head impact datasets hinders the broad clinical applications of current MLHMs. We propose brain deformation estimators that integrates unsupervised domain adaptation with a deep neural network to predict whole-brain maximum principal strain (MPS) and MPS rate (MPSR). With 12,780 simulated head impacts, we performed unsupervised domain adaptation on on-field head impacts from 302 college football (CF) impacts and 457 mixed martial arts (MMA) impacts using domain regularized component analysis (DRCA) and cycle-GAN-based methods. The new model improved the MPS/MPSR estimation accuracy, with the DRCA method significantly outperforming other domain adaptation methods in prediction accuracy (p<0.001): MPS RMSE: 0.027 (CF) and 0.037 (MMA); MPSR RMSE: 7.159 (CF) and 13.022 (MMA). On another two hold-out test sets with 195 college football impacts and 260 boxing impacts, the DRCA model significantly outperformed the baseline model without domain adaptation in MPS and MPSR estimation accuracy (p<0.001). The DRCA domain adaptation reduces the MPS/MPSR estimation error to be well below TBI thresholds, enabling accurate brain deformation estimation to detect TBI in future clinical applications

Substantia Nigra Volume Dissociates Bradykinesia and Rigidity from Tremor in Parkinson’s Disease: A 7 Tesla Imaging Study

Background: In postmortem analysis of late stage Parkinson’s disease (PD) neuronal loss in the substantial nigra (SN) correlates with the antemortem severity of bradykinesia and rigidity, but not tremor. Objective: To investigate the relationship between midbrain nuclei volume as an in vivo biomarker for surviving neurons in mild-to-moderate patients using 7.0 Tesla MRI. Methods: We performed ultra-high resolution quantitative susceptibility mapping (QSM) on the midbrain in 32 PD participants with less than 10 years duration and 8 healthy controls. Following blinded manual segmentation, the individual volumes of the SN, subthalamic nucleus, and red nucleus were measured. We then determined the associations between the midbrain nuclei and clinical metrics (age, disease duration, MDS-UPDRS motor score, and subscores for bradykinesia/rigidity, tremor, and postural instability/gait difficulty). Results: We found that smaller SN correlated with longer disease duration (r = –0.49, p = 0.004), more severe MDS-UPDRS motor score (r = –0.42, p = 0.016), and more severe bradykinesia-rigidity subscore (r = –0.47, p = 0.007), but not tremor or postural instability/gait difficulty subscores. In a hemi-body analysis, bradykinesia-rigidity severity only correlated with SN contralateral to the less-affected hemi-body, and not contralateral to the more-affected hemi-body, possibly reflecting the greatest change in dopamine neuron loss early in disease. Multivariate generalized estimating equation model confirmed that bradykinesia-rigidity severity, age, and disease duration, but not tremor severity, predicted SN volume

Soliton Dynamics in Computational Anatomy

Computational anatomy (CA) has introduced the idea of anatomical structures being transformed by geodesic deformations on groups of diffeomorphisms. Among these geometric structures, landmarks and image outlines in CA are shown to be singular solutions of a partial differential equation that is called the geodesic EPDiff equation. A recently discovered momentum map for singular solutions of EPDiff yields their canonical Hamiltonian formulation, which in turn provides a complete parameterization of the landmarks by their canonical positions and momenta. The momentum map provides an isomorphism between landmarks (and outlines) for images and singular soliton solutions of the EPDiff equation. This isomorphism suggests a new dynamical paradigm for CA, as well as new data representation.Comment: published in NeuroImag

Substantia Nigra Volume Dissociates Bradykinesia and Rigidity from Tremor in Parkinson’s Disease: A 7 Tesla Imaging Study

Background: In postmortem analysis of late stage Parkinson’s disease (PD) neuronal loss in the substantial nigra (SN) correlates with the antemortem severity of bradykinesia and rigidity, but not tremor. Objective: To investigate the relationship between midbrain nuclei volume as an in vivo biomarker for surviving neurons in mild-to-moderate patients using 7.0 Tesla MRI. Methods: We performed ultra-high resolution quantitative susceptibility mapping (QSM) on the midbrain in 32 PD participants with less than 10 years duration and 8 healthy controls. Following blinded manual segmentation, the individual volumes of the SN, subthalamic nucleus, and red nucleus were measured. We then determined the associations between the midbrain nuclei and clinical metrics (age, disease duration, MDS-UPDRS motor score, and subscores for bradykinesia/rigidity, tremor, and postural instability/gait difficulty). Results: We found that smaller SN correlated with longer disease duration (r = –0.49, p = 0.004), more severe MDS-UPDRS motor score (r = –0.42, p = 0.016), and more severe bradykinesia-rigidity subscore (r = –0.47, p = 0.007), but not tremor or postural instability/gait difficulty subscores. In a hemi-body analysis, bradykinesia-rigidity severity only correlated with SN contralateral to the less-affected hemi-body, and not contralateral to the more-affected hemi-body, possibly reflecting the greatest change in dopamine neuron loss early in disease. Multivariate generalized estimating equation model confirmed that bradykinesia-rigidity severity, age, and disease duration, but not tremor severity, predicted SN volume