174 research outputs found

    Deep brain stimulation for disorders of consciousness and diminished motivation:A search for awakenings

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    This thesis deals with patients who are amongst the most severely affected after severe brain injury: those with permanent disorders of consciousness or diminished motivation. The research in this thesis is an attempt to improve consciousness and the general behavioral performance of these patients with the use of experimental interventions, including medication (such as zolpidem), and more invasive procedures, such as deep brain stimulation (DBS). The thesis contains extensive descriptions of the role of the intralaminar thalamus in the arousal regulation system, the importance of recognizing and treating secondary complications after brain injury, such as hydrocephalus, as well as a pathophysiological elaboration on akinetic mutism: a severe disorder of diminished motivation. Moreover, it describes the neurophysiological changes that accompany the paradoxical effects of zolpidem, a sleeping pill that temporarily induces ‘awakenings’ in some patients with severe brain injury. Further, it describes the first clinical and neurophysiological results of an N=6 trial of DBS in patients with a minimally conscious state and shows the importance of recognizing pathological changes from the brain’s ‘physiological baseline’ that seem to disturb normal brain functions. The thesis concludes with a description of the use of moral case deliberation in dealing with research dilemmas in patients with loss of autonomy after severe brain injury

    Outside the pale : a collective insight into the worded illumination of experience

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    Poetry is spontaneous utterance. When a poet is presenting his/her poems, it is a movement that lives in its own existence; likewise, a poem lives as itself. To constantly become his/her self, the poet seeks limits, surpasses them, then discovers and surpasses yet newer ones, much like storming the gates of hell to reveal that evil exists in the mind. Poetry is a means of realizing, then transcending, the personal self; it demands of the poet a commitment to live with the utmost passion inherent in his/her self to live life deeply, directly, and dare to feel, to dance and celebrate the passing moment for all it is worth, to laugh the wild, free laugh of humanity. As a poet, I realize that my primary function is to move the individual to enable his/her self to identify with another\u27s life, or vision, to make its own what it is not and yet is capable of being. From outside the pale, I attempt to provoke people to look outside of themselves, to deliver them from the limited ways in which they see and feel, so that they may glimpse a divine sensibility latent in their unconscious mind, a sensibility which must be rendered attainable through words. Poetry, then, is somewhat of an incantation to another, freer, purer realm: a dimension of sometimes painful awareness open to all who refuse to live life on the surface alone. While a 553892 ii poet--along with painting, dance, theatre, film, poetry~is a process him/herself, the permanent function of art is, for me, to recreate as every individual\u27s experience the fullness of humanity at large: the collective, ultimately the divine. If this process is to transform my poetry to associations beyond its themes, each poem must build to a realization of mood rather than a sequence of events; thus, the thought that has gone into the poems is primarily pictorial and not explanatory, impressionist and not analytic. This thesis is a fragment of process; with the poems that follow, I am saying, as a poet, this is where I am now. Not yesterday. Not tomorrow. Yet it is a chapter now closed, and it is every bit as important by itself as it will be for the chapters, down the road, to follow

    Joint Recital: Lydia Arnts and Isabel Vigliotti, soprano

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    Deep brain stimulation of the central thalamus restores arousal and motivation in a zolpidem-responsive patient with akinetic mutism after severe brain injury

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    After severe brain injury, zolpidem is known to cause spectacular, often short-lived, restorations of brain functions in a small subgroup of patients. Previously, we showed that these zolpidem-induced neurological recoveries can be paralleled by significant changes in functional connectivity throughout the brain. Deep brain stimulation (DBS) is a neurosurgical intervention known to modulate functional connectivity in a wide variety of neurological disorders. In this study, we used DBS to restore arousal and motivation in a zolpidem-responsive patient with severe brain injury and a concomitant disorder of diminished motivation, more than 10 years after surviving hypoxic ischemia. We found that DBS of the central thalamus, targeted at the centromedian-parafascicular complex, immediately restored arousal and was able to transition the patient from a state of deep sleep to full wakefulness. Moreover, DBS was associated with temporary restoration of communication and ability to walk and eat in an otherwise wheelchair-bound and mute patient. With the use of magnetoencephalography (MEG), we revealed that DBS was generally associated with a marked decrease in aberrantly high levels of functional connectivity throughout the brain, mimicking the effects of zolpidem. These results imply that 'pathological hyperconnectivity' after severe brain injury can be associated with reduced arousal and behavioral performance and that DBS is able to modulate connectivity towards a 'healthier baseline' with lower synchronization, and, can restore functional brain networks long after severe brain injury. The presence of hyperconnectivity after brain injury may be a possible future marker for a patient's responsiveness for restorative interventions, such as DBS, and suggests that lower degrees of overall brain synchronization may be conducive to cognition and behavioral responsiveness

    Genetic and physiological dissection of transpiration efficiency in wheat

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    OBJECTIVE: To determine the incidence and prevalence of facioscapulohumeral muscular dystrophy (FSHD) in the Netherlands. METHODS: Using 3-source capture-recapture methodology, we estimated the total yearly number of newly found symptomatic individuals with FSHD, including those not registered in any of the 3 sources. To this end, symptomatic individuals with FSHD were available from 3 large population-based registries in the Netherlands if diagnosed within a 10-year period (January 1, 2001 to December 31, 2010). Multiplication of the incidence and disease duration delivered the prevalence estimate. RESULTS: On average, 52 people are newly diagnosed with FSHD every year. This results in an incidence rate of 0.3/100,000 person-years in the Netherlands. The prevalence rate was 12/100,000, equivalent to 2,000 affected individuals. CONCLUSIONS: We present population-based incidence and prevalence estimates regarding symptomatic individuals with FSHD, including an estimation of the number of symptomatic individuals not present in any of the 3 used registries. This study shows that the total number of symptomatic persons with FSHD in the population may well be underestimated and a considerable number of affected individuals remain undiagnosed. This suggests that FSHD is one of the most prevalent neuromuscular disorders

    Formaldehyde, glyoxal, and methylglyoxal in air and cloudwater at a rural mountain site in central Virginia

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    As part of the Shenandoah Cloud and Photochemistry Experiment (SCAPE), we measured formaldehyde (HCHO), glyoxal (CHOCHO), and methylglyoxal (CH3C(O)CHO) concentrations in air and cloudwater at Pinnacles (elevation 1037 m) in Shenandoah National Park during September 1990. Mean gas‐phase concentrations of HCHO and CHOCHO were 980 and 44 pptv, respectively. The concentration of CH3C(O)CHO rarely exceeded the detection limit of 50 pptv. Mean cloudwater concentrations of HCHO and CHOCHO were 9 and 2 ÎŒM, respectively; the mean CH3C(O)CHO concentration was below its detection limit of 0.3 ÎŒM. The maximum carbonyl concentrations were observed during stagnation events with high O3, peroxides, and CO. Outside of these events the carbonyls did not correlate significantly with O3, CO, or NOy. Carbonyl concentrations and concentration ratios were consistent with a major source for the carbonyls from isoprene oxidation. Oxidation of CH4 supplies a significant background of HCHO. The carbonyl concentrations were indistinguishable in two size fractions of cloudwater having a cut at d=18 ÎŒm. Gas‐ and aqueous‐phase concentrations of HCHO from samples collected during a nighttime cloud event agree with thermodynamic equilibria within a factor of 2. Samples collected during a daytime cloud event show HCHO supersaturation by up to a factor of 4. Positive artifacts in the cloudwater samples due to hydrolysis of hydroxymethylhydroperoxide (HOCH2OOH) could perhaps account for this discrepancy

    An improved model for estimating emissions of volatile organic compounds from forests in the eastern United States

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    The US Department of Agriculture, Forest Service Forest Inventory and Analysis Eastwide Database is used to describe the areal extent, species composition, and tree diameter distributions of United States forests. Horizontal canopy occupancy by genera is then estimated as a function of diameter at breast height. Growing season peak foliar masses are derived from the empirical literature for canopies of deciduous and coniferous genera. A simple canopy model is used to adjust photosynthetically active solar radiation at five vertical levels in the canopy. Leaf temperature and photosynthetically active radiation derived from ambient conditions above the forest canopy are then used to drive empirical equations to estimate genus level emission rates of BVOCs vertically through forest canopies. -Author
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