5,965 research outputs found
The storage and secretion of protein by the rat submandibular gland
The proteins secreted by the rat submandibular gland in response to various secretory stimuli have been investigated. The β-adrenergic agonist isoprenaline primarily caused the secretion of glycoproteins, although a number of other species were also present, and the saliva contained a moderate level of proteolytic activity. The ɑ-adrenergic agent phenylephrine acted very differently, causing the secretion of a considerable amount of proteolytic activity, with only a very small amount of glycoprotein present in the secretion. Stimulation of the cervical sympathetic trunk caused the secretion of fluid at all frequencies from 1-20 Hz, and this was mediated via both ɑ and β-adrenoceptors. However, at 20 Hz the proteins secreted were essentially similar to those obtained after phenylephrine, indicating that β-adrenoceptors were not involved in protein secretion. At the lower frequency of 5 Hz protein secretion appeared to be mediated via both a and β-adrenoceptors. Acetyl β-methyl choline and physalaemin were involved mainly with fluid secretion, although acetyl β-methyl choline caused the secretion of some proteolytic activity. Surprisingly this was not the case for parasympathetic nerve stimulation. The effect of reserpine upon the carbohydrate histochemistry of the rat submandibular gland was also investigated. This agent was found to cause an accumulation of carboxylated glycoproteins within the acini, which normally contain a neutral glycoprotein population. This result contrasts with the findings of previous investigations, where reserpine caused a simple accumulation of the glycoproteins normally present in the acini, with no qualitative changes
The influence of habitat quality on the foraging strategies of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis megidis
Entomopathogenic nematodes (EPN) are soil-transmitted parasites and their foraging strategies are believed to range from ‘ambush’ to ‘cruise’ foragers. However, research on their behaviour has not considered the natural habitat of these nematodes. We hypothesized that EPN behaviour would be influenced by soil habitat quality and tested this hypothesis using 2 EPN species Steinernema carpocapsae (an ‘ambusher’) and Heterorhabditis megidis (a ‘cruiser’) in 2 contrasting habitats, sand and peat. As predicted from previous studies, in sand most S. carpocapsae remained at the point of application and showed no taxis towards hosts, but in peat S. carpocapsae dispersed much more and showed a highly significant taxis towards hosts. H. megidis dispersed well in both media, but only showed taxis towards hosts in sand. In outdoor mesocosms in which both species were applied, S. carpocapsae outcompeted H. megidis in terms of host finding in peat, whereas the opposite was true in sand. Our data suggest that these 2 EPN may be habitat specialists and highlight the difficulties of studying soil-transmitted parasites in non-soil media
Kiwi forego vison in the guidance of their nocturnal activities
We propose that the Kiwi visual system has undergone adaptive regression evolution driven by the trade-off between the relatively low rate of gain of visual information that is possible at low light levels, and the metabolic costs of extracting that information
Comparative Analysis of Molecular Clouds in M31, M33 and the Milky Way
We present BIMA observations of a 2\arcmin field in the northeastern spiral
arm of M31. In this region we find six giant molecular clouds that have a mean
diameter of 5713 pc, a mean velocity width of 6.51.2 \kms, and a mean
molecular mass of 3.0 1.6 10\Msun. The peak brightness
temperature of these clouds ranges from 1.6--4.2 K. We compare these clouds to
clouds in M33 observed by \citet{wilson90} using the OVRO millimeter array, and
some cloud complexes in the Milky Way observed by \cite{dame01} using the CfA
1.2m telescope. In order to properly compare the single dish data to the
spatially filtered interferometric data, we project several well-known Milky
Way complexes to the distance of Andromeda and simulate their observation with
the BIMA interferometer. We compare the simulated Milky Way clouds with the M31
and M33 data using the same cloud identification and analysis technique and
find no significant differences in the cloud properties in all three galaxies.
Thus we conclude that previous claims of differences in the molecular cloud
properties between these galaxies may have been due to differences in the
choice of cloud identification techniques. With the upcoming CARMA array,
individual molecular clouds may be studied in a variety of nearby galaxies.
With ALMA, comprehensive GMC studies will be feasible at least as far as the
Virgo cluster. With these data, comparative studies of molecular clouds across
galactic disks of all types and between different galaxy disks will be
possible. Our results emphasize that interferometric observations combined with
the use of a consistent cloud identification and analysis technique will be
essential for such forthcoming studies that will compare GMCs in the Local
Group galaxies to galaxies in the Virgo cluster.Comment: Accepted for Publication in the Astrophysical Journa
Excimer laser processing of inkjet-printed and sputter-deposited transparent conducting SnO2:Sb for flexible electronics
The feasibility of low-temperature fabrication of transparent electrode elements from thin films of antimony-doped tin oxide (SnO2:Sb, ATO) has been investigated via inkjet printing, rf magnetron sputtering and post-deposition excimer laser processing. Laser processing of thin films on both glass and plastic substrates was performed using a Lambda Physik 305i excimer laser, with fluences in the range 20–100 mJ cm− 2 reducing sheet resistance from as-deposited values by up to 3 orders of magnitude. This is consistent with TEM analysis of the films that shows a densification of the upper 200 nm of laser-processed regions
Predicting functional outcomes after stroke: An observational study of acute single-channel EEG
Background: Early and objective prediction of functional outcome after stroke is an important issue in rehabilitation. Electroencephalography (EEG) has long been utilized to describe and monitor brain function following neuro-trauma, and technological advances have improved usability in the acute setting. However, skepticism persists whether EEG can provide the same prognostic value as neurological examination. Objective: The current cohort study examined the relationship between acute single-channel EEG and functional outcomes after stroke. Methods: Resting-state EEG recorded at a single left pre-frontal EEG channel (FP1) was obtained from 16 adults within 72 h of first stroke. At 30 and 90 days, measures of disability (modified Rankin Scale; mRS) and involvement in daily activities (modified Barthel Index; mBI) were obtained. Acute EEG measures were correlated with functional outcomes and compared to an early neurological examination of stroke severity using the National Institute of Health Stroke Scale (NIHSS). Classification of good outcomes (mRS ≤1 or mBI ≥95) was also examined using Receiver Operator Curve analyses. Results: One-third to one-half of participants experienced incomplete post-stroke recovery, depending on the time point and measure. Functional outcomes correlated with acute theta values (rs 0.45–0.60), with the strength of associations equivalent to previously reported values obtained from conventional multi-channel systems. Acute theta values ≥0.25 were associated with good outcomes, with positive (67-83%) and negative predictive values (70-90%) comparable to those obtained using the NIHSS. Conclusions: Acute, single-channel EEG can provide unique, non-overlapping clinical information, which may facilitate objective prediction of functional outcome after stroke
Chemotherapy-Associated Liver Injury in Patients with Colorectal Liver Metastases: A Systematic Review and Meta-analysis
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