First light from a kilometer-baseline Scintillation Auroral GPS Array.

We introduce and analyze the first data from an array of closely spaced Global Positioning System (GPS) scintillation receivers established in the auroral zone in late 2013 to measure spatial and temporal variations in L band signals at 100-1000 m and subsecond scales. The seven receivers of the Scintillation Auroral GPS Array (SAGA) are sited at Poker Flat Research Range, Alaska. The receivers produce 100 s scintillation indices and 100 Hz carrier phase and raw in-phase and quadrature-phase samples. SAGA is the largest existing array with baseline lengths of the ionospheric diffractive Fresnel scale at L band. With an initial array of five receivers, we identify a period of simultaneous amplitude and phase scintillation. We compare SAGA power and phase data with collocated 630.0 nm all-sky images of an auroral arc and incoherent scatter radar electron precipitation measurements, to illustrate how SAGA can be used in multi-instrument observations for subkilometer-scale studies. KEY POINTS: A seven-receiver Scintillation Auroral GPS Array (SAGA) is now at Poker Flat, Alaska SAGA is the largest subkilometer array to enable phase/irregularities studies Simultaneous scintillation, auroral arc, and electron precipitation are observed.

Inflammatory myofibroblastic tumours of the liver - a systematic review.

BACKGROUND: Hepatic inflammatory myofibroblastic tumours (HIMTs) are rare and poorly described in the literature. Most publications are single patient case reports and lack detailed reporting on characteristics, management, and outcomes. This systematic review aimed to assess the demography, clinical presentation, typical imaging features, histopathology, treatment, and outcomes of patients presenting with HIMTs. METHODS: A systematic literature search was performed in MEDLINE (PubMed), EMBASE (Scopus), JSTOR, Cochrane CENTRAL (Cochrane Library), and the databases included in the Web of Science for studies published between 1940 and 2023 on HIMTs, including its reported synonyms. Case series or cohort studies that reported on the management and outcomes of at least four patients with histologically confirmed HIMTs were included in the analysis. RESULTS: After screening 4553 publications, 22 articles including a total of 440 patients with confirmed HIMTs were eligible for inclusion. The average age was 53.4 years (range 42.0-65.0) with a male to female ratio of 1.7:1. Abdominal pain, discomfort, fever, and loss of weight were the most common presenting symptoms. Surgical resection is the standard of care for HIMTs and is associated with low mortality of 3.4% and low disease recurrence. CONCLUSION: HIMT is a disease more often affecting middle-aged males. The lesions are typically solitary with low recurrence after treatment. The relative roles of surgical versus medical treatment remain unclear. Differences in clinical presentation, histopathology, and treatment of HIMTs compared to inflammatory myofibroblastic tumour (IMT) at extrahepatic sites could challenge the current view of IMT as a single pathological entity.

Active Precipitation of Radiation Belt Electrons Using Rocket Exhaust Driven Amplification (REDA) of Man-Made Whistlers.

Ground-based very low frequency (VLF) transmitters located around the world generate signals that leak through the bottom side of the ionosphere in the form of whistler mode waves. Wave and particle measurements on satellites have observed that these man-made VLF waves can be strong enough to scatter trapped energetic electrons into low pitch angle orbits, causing loss by absorption in the lower atmosphere. This precipitation loss process is greatly enhanced by intentional amplification of the whistler waves using a newly discovered process called rocket exhaust driven amplification (REDA). Satellite measurements of REDA have shown between 30 and 50 dB intensification of VLF waves in space using a 60 s burn of the 150 g/s thruster on the Cygnus satellite that services the International Space Station. This controlled amplification process is adequate to deplete the energetic particle population on the affected field lines in a few minutes rather than the multi-day period it would take naturally. Numerical simulations of the pitch angle diffusion for radiation belt particles use the UCLA quasi-linear Fokker Planck model to assess the impact of REDA on radiation belt remediation of newly injected energetic electrons. The simulated precipitation fluxes of energetic electrons are applied to models of D-region electron density and bremsstrahlung X-rays for predictions of the modified environment that can be observed with satellite and ground-based sensors.

Abnormally phosphorylated tau is associated with neuronal and axonal loss in experimental autoimmune encephalomyelitis and multiple sclerosis.

The pathological correlate of clinical disability and progression in multiple sclerosis is neuronal and axonal loss; however, the underlying mechanisms are unknown. Abnormal phosphorylation of tau is a common feature of some neurodegenerative disorders, such as Alzheimer's disease. We investigated the presence of tau hyperphosphorylation and its relationship with neuronal and axonal loss in chronic experimental autoimmune encephalomyelitis (CEAE) and in brain samples from patients with secondary progressive multiple sclerosis. We report the novel finding of abnormal tau phosphorylation in CEAE. We further show that accumulation of insoluble tau is associated with both neuronal and axonal loss that correlates with progression from relapsing-remitting to chronic stages of EAE. Significantly, analysis of secondary progressive multiple sclerosis brain tissue also revealed abnormally phosphorylated tau and the formation of insoluble tau. Together, these observations provide the first evidence implicating abnormal tau in the neurodegenerative phase of tissue injury in experimental and human demyelinating disease.

Neonatal 6-hydroxydopamine lesions of the frontal cortex in rats: persisting effects on locomotor activity, learning and nicotine self-administration.

Dopaminergic innervation of the frontal cortex in adults is important for a variety of cognitive functions and behavioral control. However, the role of frontal cortical dopaminergic innervation for neurobehavioral development has received little attention. In the current study, rats were given dopaminergic lesions in the frontal cortex with local micro-infusions of 6-hydroxydopamine (6-OHDA) at 1 week of age. The long-term behavioral effects of neonatal frontal cortical 6-OHDA lesions were assessed in a series of tests of locomotor activity, spatial learning and memory, and i.v. nicotine self-administration. In addition, neurochemical indices were assessed with tissue homogenization and HPLC in the frontal cortex, striatum, and nucleus accumbens of neonatal and adult rats after neonatal 6-OHDA lesions. In neonatal rats, frontal 6-OHDA lesions as intended caused a significant reduction in frontal cortical dopamine without effects on frontal cortical 5-HT and norepinephrine. The frontal cortical dopamine depletion increased 5-HT and norepinephrine levels in the nucleus accumbens. Locomotor activity assessment during adulthood in the figure-8 maze showed that lesioned male rats were hyperactive relative to sham-lesioned males. Locomotor activity of female rats was not significantly affected by the neonatal frontal 6-OHDA lesion. Learning and memory in the radial-arm maze was also affected by neonatal frontal 6-OHDA lesions. There was a general trend toward impaired performance in early maze acquisition and a paradoxical improvement at the end of cognitive testing. Nicotine self-administration showed significant lesion x sex interactions. The sex difference in nicotine self-administration with females self-administering significantly more nicotine than males was reversed by neonatal 6-OHDA frontal cortical lesions. Neurochemical studies in adult rats showed that frontal cortical dopamine and DOPAC levels significantly correlated with nicotine self-administration in the 6-OHDA-lesioned animals but not in the controls. Frontal cortical 5-HT and 5HIAA showed inverse correlations with nicotine self-administration in the 6-OHDA-lesioned animals but not in the controls. These results show that interfering with normal dopamine innervation of the frontal cortex during early postnatal development has persisting behavioral effects, which are sex-specific.

A small spacecraft for multipoint measurement of ionospheric plasma.

Measurement of ionospheric plasma is often performed by a single in situ device or remotely using cameras and radar. This article describes a small, low-resource, deployed spacecraft used as part of a local, multipoint measurement network. A B-field aligned sounding rocket ejects four of these spin-stabilized spacecraft in a cross pattern. In this application, each spacecraft carries two retarding potential analyzers which are used to determine plasma density, flow, and ion temperature. An inertial measurement unit and a light-emitting diode array are used to determine the position and orientation of the devices after deployment. The design of this spacecraft is first described, and then results from a recent test flight are discussed. This flight demonstrated the successful operation of the deployment mechanism and telemetry systems, provided some preliminary plasma measurements in a simple mid-latitude environment, and revealed several design issues.

The responses of oligodendrocyte precursor cells, astrocytes and microglia to a cortical stab injury, in the brain.

The cortical stab injury has been widely used for biochemical analysis of molecular changes following CNS injury. However, the cellular responses to this injury have not been accurately quantified. In order to provide a baseline for biochemical studies and future experiments on the manipulation of the CNS injury response we have undertaken a quantitative analysis of this injury. The proliferative and reactive responses of oligodendrocyte precursor cells, astrocytes and microglia were measured, using antibodies to NG2, glial fibrillary acidic protein (GFAP) and the cd11-b clone OX-42 to characterise these cell types at 2, 4, 7 and 14 days post-injury. Oligodendrocyte precursors and microglia proliferated rapidly during the first week, mostly within 0.3 mm of the lesion. Of the dividing cells over 60% were oligodendrocyte precursor cells with microglia making up the balance of the dividing cells. Minimal numbers of astrocytes divided in response to the lesion. Large cells with one or two short processes that were both NG2 and OX-42 positive were identified very close to the lesion at 2 and 4 days post-lesion but not thereafter. They are likely to be blood-derived cells that express NG2 or have ingested it. NG2 immunohistochemistry and platelet-derived growth factor alpha receptor (PDGFalpha-R) in situ hybridisation on neighbouring sections was performed. In the lesioned area only 12% of NG2 positive (+ive) cells were PDGFalpha-R +ive (a ratio of 1:8 for PDGFalpha-R +ive cells: NG2 +ive cells) compared with 33% in the unlesioned cortex and an almost 100% overlap in the spinal cord.

Altered CNS response to injury in the MRL/MpJ mouse.

The MRL/MpJ mouse has a greatly enhanced healing response and an absence of scarring compared with other mouse strains. Following lesions to the CNS mammals show a scarring response known as reactive gliosis, and this CNS scar tissue blocks regeneration of cut axons. We have therefore compared reactive gliosis in the MRL/MpJ mouse and the Swiss Webster mouse, which exhibits normal scarring in the periphery. The lesion model was a stab lesion to the cortex, in which reactive gliosis has previously been quantified. Axon regeneration was examined following a cut lesion to the dopaminergic projection from the substantia nigra to the striatum used in previous regeneration experiments. In the MRL/MpJ following the lesion compared with Swiss Webster mice there was greater cell loss around the lesion followed by greater and more widespread and more prolonged cellular proliferation. Early after the lesion there was a greater loss of glial fibrillary acidic protein (GFAP)-positive astrocytes around the injury site in the MRL/MpJ, and an enhancement and prolongation of the microglial inflammatory response. This was accompanied by greater and more widespread blood-brain barrier leakage following injury. RNA levels for the matrix metalloproteinases (MMP)-2 and MMP-9 as well as for the thrombin receptors PAR-1 and PAR-4 were also greater at the MRL/MpJ injury site. All of these differences were transient and by 14 days post-injury there were no differences observed between MRL/MpJ and control mice. No axonal regeneration was observed following axotomy to the nigrostriatal pathway of the MRL/MpJ or the Swiss Webster mice at any time point.

Fusional response to extrafoveal stimulation.

Horizontal and vertical fusional responses to extrafoveal stimulation were examined. An objective binocular eye movement measuring technique was utilized to position an artificial, stabilized scotoma over the central 10 degrees diameter area of one eye. The responses contained both a motor and nonmotor, or sensory, component. The monocular eye movements were asymmetrical.

Role of Ca2+-permeable non-NMDA glutamate receptors in spinal nociceptive transmission.

The functional role of Ca2+-permeable non-NMDA receptors in spinal nociceptive processing was investigated using joro spider toxin (JSTx), a selective blocker of these receptors. JSTx 0.25 and 1 microg administered spinally produced a significant facilitation of the C-fibre evoked response and post-discharge, but not the A-fibre response, of dorsal horn neurones recorded in adult rats. This may result from a block of Ca2+-permeable AMPA receptors located on GABAergic interneurones. At higher doses, this facilitation of responses was lost, suggesting additional Ca2+-permeable non-NMDA receptors, possibly kainate receptors, in excitatory spinal pathways. Thus, functional Ca2+-permeable AMPA receptors are present within the dorsal horn, predominantly within inhibitory pathways, and play a role distinct from other excitatory amino acid receptors in spinal nociceptive processing.

The effect of lithium therapy on arginine vasopressin secretion and thirst in man.

Lithium therapy is known to reduce the renal responsiveness to arginine vasopressin (AVP: the antidiuretic hormone in man) and a proportion of treated patients develop polyuria and polydipsia. In this study seven nonpolyuric female patients receiving lithium treatment for an affective disorder (lithium group) were age-matched with seven healthy females (control group). The mean response of plasma AVP to osmotic stimulation was significantly enhanced in the lithium group but the mean osmotic threshold for AVP release was unchanged. Thirst appreciation in the lithium group commenced and increased overall at an osmotic stimulus 5 mmol/kg less than the control group. It is suggested that primary thirst does play a role in the expression of lithium-induced polyuria.

EPR characterization of alcohol complexes of ferric myoglobin and hemoglobin.

Frozen solution electron paramagnetic resonance spectra of the aquo, methanol, and ethanol complexes of ferric myoglobin and hemoglobin are quantitatively analyzed in terms of the rhombic to tetragonal symmetry ratio and the admixture of quartet states, both with regard to central values of these parameters and the widths of their distributions. In both the methanol and ethanol complexes of ferric myoglobin the main change from the aquo complex is a narrowing of the spread in the rhombic to tetragonal symmetry ratio (reduction in structural variation). The alcohol complexes of both the alpha- and beta-chains within the tetramer of ferric hemoglobin are characterized by a lowering of symmetry (as compared with the aquo complex). Qualitative differences in distribution widths among the complexes are consistent with an origin in molecular structure and dynamics rather than in ice matrix-induced strain.

Radioimmunoassays of arginine vasopressin and atrial natriuretic peptide: application of a common protocol for plasma extraction using Sep-Pak C18 cartridges.

A rapid vacuum-driven procedure, using pre-treated Sep-Pak C18 cartridges, has been developed for the simultaneous extraction of arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) from plasma. Non-specific interference was removed by fractional elution with an aqueous methanol/trifluoroacetic acid (TFA) mixture. AVP and ANP were coeluted under positive pressure with a methanol/TFA mixture and the eluates air-dried before measurement using separate radioimmunoassays. Assay ranges for AVP and ANP were 0.12-29.5 pmol/L and 0.65-162 pmol/L, respectively, with mean recoveries (standard deviation in parentheses) for AVP of 96.4% (5.5%) at a level of 11.8 pmol/L and for ANP of 94.8% (5.9%) at a level of 32.4 pmol/L. The extraction and assay procedures were validated by observing the changes in plasma AVP and ANP concentrations in normal subjects at different stages of hydration and in elderly patients during treatment for congestive cardiac failure.

Corn oil ketogenic diet for children with intractable seizures.

The ketogenic diet is a well-established, but relatively infrequently used, therapy for intractable seizures in children. Currently, the standard ketogenic diet is formulated using medium chain triglyceride (MCT) oil as its major caloric source. Cost, availability, and gastrointestinal side effects limit its use in some cases. We report the successful substitution of corn oil for MCT oil in six children treated with the ketogenic diet for intractable seizures. In each case, the corn oil ketogenic diet was effective, well-tolerated by the patient and parents, and free of clinical toxicity. Corn oil also has the major advantages of being much less expensive and more available that MCT oil. Its use in the ketogenic diet appears to be effective, safe, and practical.

Healing potential of the anulus fibrosus.

The purpose of this study was to investigate the healing of surgically created defects in the anulus fibrosus in an effort to determine the healing potential of this structure. Four identical lesions were made in the anulus fibrosus of ten dogs at levels L2-L5. Two dogs were killed at 3, 6, and 9 weeks. Four dogs were killed at 12 weeks. The spines were harvested during a 3- to 12-week period and evaluated grossly and microscopically. Our study demonstrated that a stab wound of the anulus has a limited healing potential and the persisting defect could provide a pathway for irritating nuclear fluid escape onto perineural tissue, possibly resulting in persistent low-back pain.

Biomechanical properties of threaded inserts for lumbar interbody spinal fusion.

STUDY DESIGN: Calf and human cadaveric spines were used to determine motion segment stiffness and laxity after implantation of threaded inserts (the Ray Threaded Fusion Cage, Surgical Dynamics, Inc., Concord, CA), comparing direction of placement, number of implants, shape of the device, and integrity of anterior spine structures. Stiffness and laxity of spines with inserts were compared with those with bone grafts, with and without posterior fixation plates. OBJECTIVES: To determine the mechanical stabilizing properties of a threaded insert used for lumbar and lumbosacral fusion and the factors affecting stability. SUMMARY OF BACKGROUND DATA: Limited biomechanical information has shown that implantation of these devices adds stiffness to the lumbar spine, but little information is available concerning stiffness in loading directions other than flexion and extension, the effect on stiffness of position and number of implants, and the effect of this device on motion segment laxity. METHODS: Mechanical properties were determined by testing lumbar vertebral motion segments in flexion, extension, lateral bending, and torsion combined with axial compressive loading. Stiffness (slope of the load/deflection curve) and neutral zone angle or laxity (angular displacement of the vertebra from no load to 1.0 Nm moment) were determined. Initial tests were performed on calf lumbar vertebrae to determine the effects of placement and number of inserts. Comparisons of bone grafts and inserts with and without supplemental plates were made using human lumbar spines. Cylindrical- and conical-shaped inserts, when placed from anterior, were tested in calf spines. The load-bearing capacity of the insert supported in calf vertebral body bone was determined. RESULTS: There was no significant effect of placement of inserts in different orientations (lateral, posterolateral, or posterior) on stiffness, except in torsion where posterior placement damaged facets or lamina, reducing stiffness. Placement of two inserts from posterior decreased flexion and lateral bending laxity compared with the intact motion segment. Compared with intact, bone grafts produced more stiffness only in lateral bending and had no effect on laxity. Supplemental posterior plates fixed by pedicle screws across the fusion segment increased flexion and lateral bending stiffness and reduced laxity in flexion, extension, and lateral bending. Conical-shaped inserts placed from anterior into cylindrical holes distracted soft tissue structures, decreasing laxity. Cutting the anterior structures increased laxity by relieving some tissue tension caused by distraction. The mean maximum compressive load that could be supported by the insert was 2998 N (standard deviation = 980 N). Structural failure occurred in the supporting bone. CONCLUSIONS: Threaded inserts increase vertebral motion segment stiffness and decrease laxity by distracting intervertebral structures. They are not sensitive to placement, except if vertebral structures are injured during insertion and produce constructs with more consistent mechanical properties than bone grafts.

Facilitating the recovery of open heart surgery patients through quality improvement efforts and CareMAP implementation.

OBJECTIVE: To illustrate, using a literature review and CareMAPs, how care coordination and implementation of standard protocols can impact clinical outcomes for open heart surgery patients. METHODS: A CareMAP for open heart surgery patients was developed by a multidisciplinary team. To evaluate the effectiveness of CareMAP implementation and specific quality improvement efforts, a pilot study was done that focused on increasing activity levels, decreasing ventilator time, and decreasing the frequency of arterial blood gas sampling for a sample of 55 open heart surgery patients. A rapid recovery program was developed based on the results of this pilot study. A multidisciplinary continuous quality improvement team was developed to focus on three primary areas: ventilator weaning time, activity regimens, and early transfer to the open heart surgery step-down unit. Forty-nine open heart surgery patients were included in the initial program evaluation. RESULTS: The frequency of arterial blood gas sampling decreased from an average of 5.8 per patient to an average of 3.9 per patient. Postoperative length of stay also decreased by 1.3 days for diagnosis related group 106 patients, and 3.7 days for diagnosis related group 107 patients. Results of the pilot study demonstrated additional opportunities for improving the care of open heart surgery patients. Using the rapid recovery program, the average ventilator time decreased by 4.4 hours per patient. The average postoperative length of stay decreased to 4.7 days. CONCLUSIONS: Through the quality improvement process and through the use of CareMAPs and specific protocols, the recovery of open heart surgery patients was facilitated.

Influence of orthostatic hypotension in Parkinson's disease on plasma atrial natriuretic peptide.

The effect of orthostatic hypotension in Parkinson's disease (PD) on plasma atrial natriuretic peptide (ANP) was examined in fifteen individuals with PD without autonomic dysfunction (63-85 years), nine PD patients with autonomic dysfunction (orthostatic hypotension; systolic BP change > 20 mmHg after 5 min standing: 69-82 years) and 14 fit elderly volunteers (62-93 years). The mean ANP level was 42.2 pg/ml (range 16.8-89.2 pg/ml) in the PD group without autonomic dysfunction; 44.4 pg/ml (range 27.2-91.2 pg/ml) in the PD group with autonomic dysfunction; and 48.5 pg/ml (range 22.2-111.6 pg/ml) in the elderly group. There was no statistical difference in plasma atrial natriuretic peptide between all three groups. The mean change in blood pressure was -39 mmHg (systolic) and -18 mmHg (diastolic) between supine and standing in the group with orthostatic hypotension.

Effect of high amounts of dietary zinc and age upon tissue zinc in young chicks.

Weight gains of younger broiler chicks were not reduced by up to 2400 p.p.m. added zinc fed to four weeks of age. Tissue zinc was not changed significantly by 600 or 1200 p.p.m. supplemental dietary zinc, but at 2400 p.p.m. added zinc, blood, kidney, and liver zinc were significantly elevated (P less than 0.05). In the heart, zinc was not affected by the added dietary zinc but increased over time with all diets. Unlike the calf and weanling pig, the metabolism of zinc in the young chick does not appear to change appreciably with increasing maturity. Thus, the homeostatic control mechanisms of the young chick are effective for up to 1200 p.p.m. dietary zinc, but are partially overcome by 2400 p.p.m. added dietary zinc.

Disaster coordination and management: summary and action plans.

INTRODUCTION: Disaster is a collective responsibility requiring coordinated response from all parts of society. This theme focused on coordination and management issues in a diverse range of scenarios. METHODS: Details of the methods used are provided in the preceding paper. The chairs moderated all presentations and produced a summary that was presented to an assembly of all of the delegates. Although the main points developed in Themes 1 and 4 were different from each other (as reported in the Results section), their implementation was similar. Therefore, the chairs of both groups presided over one workshop that resulted in the generation of a set of Action Plans that then were reported to the collective group of all delegates. RESULTS: The main points developed during the presentations and discussions included: (1) the need for evidence-based assessments and planning, (2) the need for a shift in focus to health-sector readiness, (3) empowerment of survivors, (4) provision of relief for the caregivers, (5) address the incentives and disincentives to attain readiness, (6) engage in joint preparation, response, and training, (7) focus on prevention and mitigation of the damage from events, and (8) improve media relations. There exists a need for institutionalization of processes for learning from experiences obtained from disasters. DISCUSSION: Action plans presented include: (1) creation of an Information and Data Clearinghouse on Disaster Management, (2) identification of incentives and disincentives for readiness and develop strategies and interventions, and (3) act on lessons learned from evidence-based research and practical experience. CONCLUSIONS: There is an urgent need to proactively establish coordination and management procedures in advance of any crisis. A number of important insights for improvement in coordination and management during disasters emerged.