Abrasion and fatigue resistance of PDMS containing multiblock polyurethanes after accelerated water exposure at elevated temperature.

Segmented polyurethane multiblock polymers containing polydimethylsiloxane and polyether soft segments form tough and easily processed thermoplastic elastomers (PDMS-urethanes). Two commercially available examples, PurSil 35 (denoted as P35) and Elast-Eon E2A (denoted as E2A), were evaluated for abrasion and fatigue resistance after immersion in 85 °C buffered water for up to 80 weeks. We previously reported that water exposure in these experiments resulted in a molar mass reduction, where the kinetics of the hydrolysis reaction is supported by a straight forward Arrhenius analysis over a range of accelerated temperatures (37-85 °C).

Human hypocretin and melanin-concentrating hormone levels are linked to emotion and social interaction.

The neurochemical changes underlying human emotions and social behaviour are largely unknown. Here we report on the changes in the levels of two hypothalamic neuropeptides, hypocretin-1 and melanin-concentrating hormone, measured in the human amygdala. We show that hypocretin-1 levels are maximal during positive emotion, social interaction and anger, behaviours that induce cataplexy in human narcoleptics.

Three-dimensional surface maps link local atrophy and fast ripples in human epileptic hippocampus.

Objectives: There is compelling evidence that pathological high-frequency oscillations (HFOs), called fast ripples (FR, 150-500Hz), reflect abnormal synchronous neuronal discharges in areas responsible for seizure genesis in patients with mesial temporal lobe epilepsy (MTLE). It is hypothesized that morphological changes associated with hippocampal atrophy (HA) contribute to the generation of FR, yet there is limited evidence that hippocampal FR-generating sites correspond with local areas of atrophy.

Methods: Interictal HFOs were recorded from hippocampal microelectrodes in 10 patients with MTLE.

Three-dimensional hippocampal atrophy maps distinguish two common temporal lobe seizure-onset patterns.

Purpose: Current evidence suggests that the mechanisms underlying depth electrode-recorded seizures beginning with hypersynchronous (HYP) onset patterns are functionally distinct from those giving rise to low-voltage fast (LVF) onset seizures. However, both groups have been associated with hippocampal atrophy (HA), indicating a need to clarify the anatomic correlates of each ictal onset type. We used three-dimensional (3D) hippocampal mapping to quantify HA and determine whether each onset group exhibited a unique distribution of atrophy consistent with the functional differences that distinguish the two onset morphologies.

Induction of Chitinase, beta-1,3-Glucanase, and Phenylalanine Ammonia Lyase in Peach Fruit by UV-C Treatment.

ABSTRACT Treatment of peach fruit with UV-C light caused a rapid induction of chitinase, beta-1,3-glucanase, and phenylalanine ammonia lyase (PAL) activities starting 6 h after treatment and reaching maximum levels at 96 h after treatment. By 96 h after UV-C treatment, chitinase, beta-1,3-glucanase, and PAL activities in UV-C-treated fruit were over twofold above the levels observed for the control. In nontreated control fruit, no apparent increase in chitinase and beta-1,3-glucanase activities was detected but a minor increase in PAL activity was seen.

Control of Postharvest Decay of Apple Fruit with Candida saitoana and Induction of Defense Responses.

ABSTRACT The ability of Candida saitoana to induce systemic resistance in apple fruit against Botrytis cinerea was investigated. To separate the antagonistic activity of C. saitoana from its ability to induce resistance, the antagonist and the pathogen were applied in spatially separated wounds.

Alternative disease control agents induce resistance to blue mold in harvested 'red delicious' apple fruit.

ABSTRACT Alternative control agents, including UV-type C (254 nm) irradiation, yeasts antagonistic to fungal growth, chitosan and harpin, were evaluated for their ability to induce resistance in cv. Red Delicious apple fruit against postharvest blue mold caused by Penicillium expansum. Freshly harvested and controlled atmosphere (CA)-stored fruit were treated with these agents at different doses and concentrations or with paired combinations of the agents.

Cell type-specific firing during ripple oscillations in the hippocampal formation of humans.

High-frequency field ripples occur in the rodent hippocampal formation and are assumed to depend on interneuron type-specific firing patterns, structuring the activity of pyramidal cells. Ripples with similar characteristics are also present in humans, yet their underlying cellular correlates are still unknown. By in vivo recording interneurons and pyramidal cells in the human hippocampal formation, we find that cell type-specific firing patterns and phase-locking on a millisecond timescale can be distinguished during ripples.

Voltage depth profiles of high-frequency oscillations after kainic acid-induced status epilepticus.

High-frequency oscillations (HFOs) have been described in normal and epileptic brains of animals and humans. These oscillations reflect a short-term integration within neuronal networks and have important functional consequences for normal and pathological processes. We performed a comparative voltage depth profile analysis of normal and pathological HFOs after intrahippocampal kainic acid injection.

Increased fast ripple to ripple ratios correlate with reduced hippocampal volumes and neuron loss in temporal lobe epilepsy patients.

Purpose: To determine whether hippocampal sclerosis might form an anatomical substrate for pathological high-frequency oscillations in patients with temporal lobe epilepsy (TLE).

Methods: Intracerebral wide bandwidth electroencephalogram was recorded in patients with medically intractable complex partial seizures. A computer-automated program detected interictal normal ripples (80-150 Hz) and pathologic fast ripples (FR, 151-500 Hz) from microelectrodes within hippocampus, entorhinal, and subicular cortices.

Changes in extracellular glutamate levels in rat orbitofrontal cortex during sleep and wakefulness.

Background: Functional neuroimaging studies have shown that limbic and paralimbic areas display increased activity during REM sleep when compared to wakefulness. This increase in limbic activity is specific to the REM period of sleep. PET scanners do not provide a neurochemical explanation for this increased activity during REM sleep.

Characterizing interneuron and pyramidal cells in the human medial temporal lobe in vivo using extracellular recordings.

The goal of this study was to characterize the electrophysiological features of single neurons recorded deep within the medial temporal lobes in humans. Using three physiological criteria to distinguish principal cells and interneurons (firing rate, burst propensity, and action potential waveform) and a large data set of human single neurons (585) from thirteen patients, we show that single neurons in the human MTL separate into two distinct classes comparable to the pyramidal cell and interneuron classes described in animals. We also find that the four different MTL brain regions that we examined (amygdala, hippocampus, entorhinal cortex, and posterior parahippocampal cortex) show unique action potential characteristics, which may in turn relate to the role that neurons from these regions play in behavior.

Extracellular adenosine in the human brain during sleep and sleep deprivation: an in vivo microdialysis study.

Study Objectives: To examine the pattern of extracellular adenosine in the human brain during sleep deprivation, sleep, and normal wake.

Design: Following recovery from implantation of clinical depth electrodes, epilepsy patients remained awake for 40 continuous hours, followed by a recovery sleep episode.

Setting: Neurology ward at UCLA Medical Center.

Low frequency electrical stimulation through subdural electrodes in a case of refractory status epilepticus.

Objective: We delivered low frequency stimulation through subdural electrodes to suppress seizures in a case of refractory status epilepticus (RSE).

Methods: A 26-year-old female developed RSE after several days of febrile illness. Seizure control required continuous infusion of two anesthetics plus high doses of 2-4 enteral antiepileptic drugs.

Analysis of chronic seizure onsets after intrahippocampal kainic acid injection in freely moving rats.

Purpose: The goal of this study was to analyze the transition period between interictal and ictal activity in freely moving rats with recurrent spontaneous seizures after unilateral intrahippocampal kainic acid (KA) injection.

Methods: Pairs of tungsten electrodes (50 microm O/D) were implanted bilaterally under anesthesia at symmetrical points in the dentate gyrus (DG) and CA1 regions of anterior and posterior hippocampi and entorhinal cortex of adult Wistar rats. Stimulating electrodes were placed in the right angular bundle and KA was injected into the right posterior CA3 area of hippocampus after 1 week of baseline EEG recording.

A lack of effect from transcranial magnetic stimulation (TMS) on the vagus nerve stimulator (VNS).

Objective: The effects of transcranial magnetic stimulation (TMS) on vagus nerve stimulation (VNS) are unknown. Understanding these effects is important before exposing individuals with an implanted VNS to TMS, as could occur in epilepsy or depression TMS research. To explore this issue, the TMS-induced current in VNS leads and whether TMS has an effect on the VNS pulse generator was assessed.

Analysis of seizure onset on the basis of wideband EEG recordings.

Seventy-five seizure onsets recorded with depth electrodes in the frequency band from 0.1 to 70 Hz were analyzed in 19 patients with intractable temporal lobe epilepsy. It was shown that 89% of low-voltage fast-type seizures contained an initial slow wave, whereas hypersynchronous-type seizures did not show an initial slow wave.

Characterization of an S-locus receptor protein kinase-like gene from peach.

A receptor-like protein kinase gene (Ppsrkl1) was isolated from a peach (Prunus persica (L.) Batsch.) bark cDNA library prepared with RNAs isolated from bark collected in December (cold acclimated).

High-frequency oscillations after status epilepticus: epileptogenesis and seizure genesis.

Purpose: To investigate the temporal relation between high-frequency oscillations (HFOs) in the dentate gyrus and recurrent spontaneous seizures after intrahippocampal kainite-induced status epilepticus.

Methods: Recording microelectrodes were implanted bilaterally in different regions of hippocampus and entorhinal cortex. A guide cannula for microinjection of kainic acid (KA) was implanted above the right posterior CA3 area of hippocampus.

High-frequency oscillations recorded in human medial temporal lobe during sleep.

The presence of fast ripple oscillations (FRs, 200-500 Hz) has been confirmed in rodent epilepsy models but has not been observed in nonepileptic rodents, suggesting that FRs are associated with epileptogenesis. Although studies in human epileptic patients have reported that both FRs and ripples (80-200 Hz) chiefly occur during non-rapid eye movement sleep (NREM), and that ripple oscillations in human hippocampus resemble those found in nonprimate slow wave sleep, quantitative studies of these oscillations previously have not been conducted during polysomnographically defined sleep and waking states. Spontaneous FRs and ripples were detected using automated computer techniques in patients with medial temporal lobe epilepsy during sleep and waking, and results showed that the incidence of ripples, which are thought to represent normal activity in animal and human hippocampus, was similar between epileptogenic and nonepileptogenic temporal lobe, whereas rates of FR occurrence were significantly associated with epileptogenic areas.

Large-scale microarray gene expression analysis in discrete electrophysiologically identified neuronal clusters.

The normal processes of learning and memory as well as the pathological progress of various neurological diseases may result in changes in gene expression in small, local populations of neurons in any given brain area, leading to the occurrence of specific patterns of electrical activity without easily detectable changes in the morphology of this brain area. One way of identifying these changes might be the comparison of gene expression of areas which generate and areas which do not generate specific patterns of electrical activity. A method for microbiopsy of limited (0.

Electrical stimulation of the posteromedial thalamus modulates breathing in unanesthetized fetal sheep.

Having previously shown that lesions in the posteromedial group of thalamic nuclei abolish hypoxic inhibition of fetal breathing, we devised this study to identify thalamic loci that depress breathing by focal stimulation of specific sectors of the caudal thalamus and adjacent structures. Multipolar electrode arrays consisting of a series of eight stimulation contacts at 1.25-mm intervals were implanted vertically through guide cannulae into the caudal diencephalon of 12 chronically catheterized fetal sheep (>0.

Spatial stability over time of brain areas generating fast ripples in the epileptic rat.

Purpose: Fast ripples (FRs) are interictal, pathological, high-frequency oscillations in the 200- to 600-Hz range, which can be recorded from limbic regions capable of generating spontaneous seizures in rodent models of epilepsy and in human mesial temporal lobe epilepsy. To evaluate the spatial stability of FR-generating brain areas over long periods, we monitored interictal FR oscillations in rats with chronic recurrent spontaneous seizures.

Methods: After unilateral intrahippocampal injection of kainic acid, 22 rats were video monitored until spontaneous behavioral seizures occurred, and then implanted with multiple hippocampal, dentate gyrus, and entorhinal cortex microelectrodes.