Neuroinflammation and neurodegeneration following blast traumatic brain injury

Blast traumatic brain injury (bTBI) is the signature injury from conflicts in Iraq and Afghanistan. Although chronic neuroinflammation has been detected following TBI, little is known about this following bTBI. This thesis investigates TBI in UK military personnel before measuring neuroinflammation and neurodegeneration in personnel and an animal bTBI model. Outcomes following TBI during those conflicts were analysed. This preceded a study involving ten personnel following bTBI. A single-centre MRS and [18F]GE180 PET case-control study assessed biomarkers of neuroinflammation. Furthermore, an animal bTBI model assessed immunohistochemical and neuroimaging markers of neuroinflammation and neurodegeneration. Results showed survival improved year-on-year, except following severe TBI. Poor outcomes were driven by penetrating TBI. There were no significant changes related to neuroinflammation seen on MRS or PET, however the animal model demonstrated neuroinflammatory and neurodegenerative changes. While improved survival rates endorse the success of the UK Defence Medical Services, there remains potential to improve outcomes following severe TBI in future conflicts. Multi-centre in vivo MRS and PET studies could be useful in detecting neuroinflammation but would require PET radioligands with improved VT. Ex vivo work validates DTI for detecting injury following bTBI, identifying areas for future study. Prognostication of poor outcome following TBI is no longer a self-fulfilling prophecy

Vat 3D printable materials and post-3D printing procedures for the development of engineered devices for the biomedical field

L'abstract è presente nell'allegato / the abstract is in the attachmen

Аналіз електроенцефалограм людини, отриманих під час емоційних стимулів

Об’єктом розгляду є електрична активність головного мозку людини. Предмет роботи – методи аналізу електроенцефалограм під час дії різноманітних стимулів. Метою роботи є вивчення природи виникнення електричних сигналів мозку, методи їх реєстрації та аналізу для дослідження реакції на візуальні емоційнонавантажені стимули. У першому розділі описуються загальні поняття про природу виникнення електричного сигналу мозку людини, а також нейрофізіологічні ознаки присутності різних частотних складових сигналу за певних станів людини. У другому розділі наведено принципи реєстрації сигналів електроенцефалограми (ЕЕГ) та описано пристрої, що здатні це виконувати. Також розглянуто опис основної системи накладання сенсорів (електродів) на голову людини. В кінці розділу наведено приклад компактного 8-канального енцефалографа власної розробки, що здатен реєструвати сигнали ЕЕГ та передавати їх по бездротовому зв’язку на мобільні прилади (смартфон, планшет). Третій розділ описує основні математичні методи аналізу ЕЕГ сигналів. Основними є методи спектрального та вейвлет-аналізу та аналіз детрендових коливань, за допомогою яких можна отримати детальне представлення про роботу мозку, шляхом виявлення різноманітних патернів в частотних діапазонах. У четвертому розділі описується практичне застосування методів спектрального та Detrended Moving Average аналізів на експериментальній базі даних ЕЕГ для 48 здорових волонтерів, запис ЕЕГ для яких проводився під час демонстрації певних емоційнонавантажених візуальних стимулів. Також в цьому розділі наведені результати виконаного аналізу разом з їх нейрофізіологічним тлумаченням.An important place in the study of brain activity is occupied by the study of its electrical potentials. Electroencephalography (EEG) is a method of graphical recording of brain biopotentials, which allows analyzing its physiological maturity and condition, the presence of focal lesions, general brain disorders and their nature. It consists of recording and analyzing the total bioelectric activity of the brain — an electroencephalogram (EEG). EEG can be taken from the scalp, from the surface of the brain, as well as from deep brain structures. As a rule, an electroencephalogram is understood as a surface recording, that is, made from the intact head surface. EEG is most often used to diagnose epilepsy, which causes EEG disorders. It is also used to diagnose sleep disorders, deep anesthesia, coma, encephalopathy, and brain death. EEG was used as the main method for diagnosing tumors, stroke, and other focal brain diseases, but when it became possible to obtain high-resolution anatomical images using magnetic resonance imaging (MRI) and computed tomography (CT) techniques, the use of EEG declined. Despite its limited resolution, the EEG continues to be a valuable tool for research and diagnosis. The object of consideration is the electrical activity of the human brain. The subject of the work is methods of analyzing electroencephalograms during the action of various stimuli. The aim of the work is to study the nature of the occurrence of electrical signals of the brain, methods of their registration and analysis to study the response to visual emotional stimuli. The first chapter describes general concepts about the nature of the occurrence of an electrical signal in the human brain, as well as neurophysiological signs of the presence of various frequency components of the signal in certain human states. The second chapter describes the principles of recording electroencephalogram signals and describes devices that can perform this. The description of the main system for applying sensors (electrodes) to the human head is also considered. At the end of the section, an example of a compact 8-channel encephalograph of our own design is given, which is able to register EEG signals and transmit them wirelessly to mobile devices (smartphone, tablet). The third section describes the basic mathematical methods for analyzing EEG signals. The main methods are spectral and wavelet analysis and detrended oscillation analysis, which can be used to get a detailed picture of brain function by identifying various patterns in frequency ranges. The fourth section describes the practical application of spectral and Detrended Moving Average analysis methods on an experimental EEG database. Here, initially the EEG records were made for 48 healthy volunteers whose EEG recording was performed while demonstrating certain emotionally loaded visual stimuli. Stimuli were selected from the International Affective Pictures System (IAPS) based on their average emotional valence values. In order to assess the induced changes of the brain’s electrical activity, the EEG-bands were subdivided in a following way: 1 [3.5, 5.8], 2 [5.9, 7.4], 1 [7.5, 9.4], 2 [9.5, 10.7], 3 [10.8, 13.5], 1 [13.6, 25], 2 [25.1, 40] Hz. As a result, Power Spectral Density (PSD) were visualized as a map on the schematic figure of the head used to render the statistical significance test, demonstrating that variations in powers for our signals were caused by non-identical forms of visual effect rather than being an accident. These details were also shown in the heads charts. The study of changes in power spectrum density showed neurodynamics triggered by visual stimulation experience. However, when comparing PSD values obtained during the presentation of the first and second neutral series, it was discovered that when processing neutral images followed by negative stimuli, a well-defined activation focus developed in the left parietal region of the cortex in the 2 subband. The DMA algorithm revealed statistically important variations in the left temporal and frontal regions of the cortex, which were marked by more pronounced activation during the perception of neutral faces in the presence of positive images. This may be the start of a new path of improved inner focus and meaningful emotional experiences. As a result, the sex-related aspects of the emotional valence effect on neutral face perception were discovered by analyzing EEG-based brain neurodynamics in the mechanism in perception in human faces of various modalities. The stimulation of two large cognitive networks in the brain: mental or theta-network and cognitive beta- network, was the key distinction

Using MapReduce Streaming for Distributed Life Simulation on the Cloud

Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

An evaluation of central and cerebral haemodynamic interactions in chronic obstructive pulmonary disease

Abstract Background: Chronic obstructive pulmonary disease (COPD) is characterised by airflow obstruction, an independent predictor of increased cardiovascular risk including stroke. Cardiovascular risk can be predicted by central haemodynamics including arterial stiffness as measured by aortic pulse wave velocity (aPWV) and central pulse pressure (CPP) in addition to cerebral haemodynamics as measured by middle cerebral artery pulsatility index (MCAPI). Arterial stiffness is increased in COPD, which may be linked to the cerebral haemodynamics and risk of stroke. This study aimed to investigate the associations between central and cerebral haemodynamics and measures of health status in patients with COPD compared to aged-matched controls. Method: The thesis comprises of three studies: • A longitudinal study included three assessment timepoints (baseline, 2 and 6 years) in patients with COPD and controls. Detailed arterial assessments included aPWV and CPP using the SphygmoCor system. Lung function was assessed using forced expiratory volume in the first second/ forced vital capacity (FEV1/FVC) measured using spirometry. Health status included the measurement of physical function using the validated Time-Up-and-Go test (TUG) and the Six-minute Walking Test (6MWT), as well as subjective measures including the Comprehensive Geriatric Assessment (CGA), the COPD Assessment tool (CAT) and the St George's Respiratory Questionnaire (SGRQ). • A cross-sectional study investigating the differences in patients with COPD and controls included all above assessments, with the addition of middle cerebral artery pulsatility index (MCAPI) using transcranial Doppler ultrasound. • A cross-sectional study investigated differences in cerebral volumes (white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF) volumes) using MRI in patients with COPD and controls. iii Results: • The longitudinal study included 75 patients with COPD and 71 controls. At each assessment time-point, aPWV remained significantly higher in COPD patients than controls but both groups showed a similar change in aPWV. After 6 years, patients with COPD had lower FEV1/FVC and physical function as measured by the TUG, 6MWT and CGA, all were related to aPWV (all p<0.05). • The cross-sectional study included 45 patients with COPD and 50 controls. MCAPI was similar in COPD and controls. In COPD, MCAPI was significantly associated with CPP (r=0.433, P=0.003) and FEV1/FVC (r=0.330, P=0.027), but not aPWV. In controls, MCAPI was associated with CPP (r=0.601, P=0.001) and aPWV (r=0.452, P=0.001). In COPD, using Stepwise Multiple Regression Analysis, CPP remained an independent predictor of MCAPI (P=0.003). • Pilot data from 6 patients with COPD and 6 aged and gender-matched controls showed no difference in cerebral volumes between the groups. MCAPI was associated with GM and CSF volumes, with no association between aPWV or CPP and cerebral volumes. Conclusion: Patients with COPD have increased arterial stiffness, cardiovascular comorbidities and poorer health status compared to matched controls. The chronically increased and maintained higher levels of aPWV suggests premature vascular ageing and increased cardiovascular risk in COPD patients. Although patients with COPD had increased aPWV, only CPP was independently associated with cerebral flow pulsatility, suggesting the utility of CPP to potentially indicate and monitor cerebrovascular changes throughout disease. The relationship between cerebral pulsatility and cerebral volumes measured by MRI suggests a potential role of MCAPI in cardiovascular risk prediction. However, further large-scale studies are needed to improve understanding of the systemic mechanisms underlying cardiovascular risks and their interaction with comorbidities to improve outcomes in COPD

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion