4,359 research outputs found
The Effect of NAG–thiazoline on Morphology and Surface Hydrophobicity of Escherichia Coli
The β-hexosaminidase inhibitor and structural analog of the putative oxazolium reaction intermediate of lytic transglycosylases, N-acetylglucosamine thiazoline (NAG–thiazoline), was synthesized in 46% overall yield and tested as an inhibitor of Escherichia coli growth. NAG–thiazoline, at concentrations up to 1 mg/ml, was not found to affect the viability of E. coli DH5α
Depth-dependent resolution quantification in 3D fluorescence microscopy
A method is presented to quantify resolution as a function of depth in
features of morphologically complex 3D samples. Applying the method to the
brain of Drosophila, resolution is measured at increasing depth throughout the
central brain region. The results quantify improvements in image quality when
using two-photon microscopy compared to confocal. It is also demonstrated how
resolution improvements through tuning a single parameter, laser power, can be
measured objectively. Since the metric is interpretable as the average
resolution within a feature, it is suitable for comparing results across
optical systems, and can be used to inform the design of biological experiments
requiring resolution of structures at a specific scale.Comment: 8 pages, 3 figure
A practical model of convective dynamics for stellar evolution calculations
Turbulent motions in the interior of a star play an important role in its
evolution, since they transport chemical species, thermal energy and angular
momentum. Our overall goal is to construct a practical turbulent closure model
for convective transport that can be used in a multi-dimensional stellar
evolution calculation including the effects of rotation, shear and magnetic
fields. Here, we focus on the first step of this task: capturing the well-known
transition from radiative heat transport to turbulent convection with and
without rotation, as well as the asymptotic relationship between turbulent and
radiative transport in the limit of large Rayleigh number. We extend the
closure model developed by Ogilvie (2003) and Garaud and Ogilvie (2005) to
include heat transport and compare it with experimental results of
Rayleigh-Benard convection.Comment: Conference proceeding for poster at conference "Unsolved problems in
Stellar Physics
State-space solutions to the dynamic magnetoencephalography inverse problem using high performance computing
Determining the magnitude and location of neural sources within the brain
that are responsible for generating magnetoencephalography (MEG) signals
measured on the surface of the head is a challenging problem in functional
neuroimaging. The number of potential sources within the brain exceeds by an
order of magnitude the number of recording sites. As a consequence, the
estimates for the magnitude and location of the neural sources will be
ill-conditioned because of the underdetermined nature of the problem. One
well-known technique designed to address this imbalance is the minimum norm
estimator (MNE). This approach imposes an regularization constraint that
serves to stabilize and condition the source parameter estimates. However,
these classes of regularizer are static in time and do not consider the
temporal constraints inherent to the biophysics of the MEG experiment. In this
paper we propose a dynamic state-space model that accounts for both spatial and
temporal correlations within and across candidate intracortical sources. In our
model, the observation model is derived from the steady-state solution to
Maxwell's equations while the latent model representing neural dynamics is
given by a random walk process.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS483 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Triceps Surae Short Latency Stretch Reflexes Contribute to Ankle Stiffness Regulation during Human Running
During human running, short latency stretch reflexes (SLRs) are elicited in the triceps surae muscles, but the function of these responses is still a matter of controversy. As the SLR is primarily mediated by Ia afferent nerve fibres, various methods have been used to examine SLR function by selectively blocking the Ia pathway in seated, standing and walking paradigms, but stretch reflex function has not been examined in detail during running. The purpose of this study was to examine triceps surae SLR function at different running speeds using Achilles tendon vibration to modify SLR size. Ten healthy participants ran on an instrumented treadmill at speeds between 7 and 15 km/h under 2 Achilles tendon vibration conditions: no vibration and 90 Hz vibration. Surface EMG from the triceps surae and tibialis anterior muscles, and 3D lower limb kinematics and ground reaction forces were simultaneously collected. In response to vibration, the SLR was depressed in the triceps surae muscles at all speeds. This coincided with short-lasting yielding at the ankle joint at speeds between 7 and 12 km/h, suggesting that the SLR contributes to muscle stiffness regulation by minimising ankle yielding during the early contact phase of running. Furthermore, at the fastest speed of 15 km/h, the SLR was still depressed by vibration in all muscles but yielding was no longer evident. This finding suggests that the SLR has greater functional importance at slow to intermediate running speeds than at faster speeds
Hydrolases in GtoPdb v.2023.1
Listed in this section are hydrolases not accumulated in other parts of the Concise Guide, such as monoacylglycerol lipase and acetylcholinesterase. Pancreatic lipase is the predominant mechanism of fat digestion in the alimentary system; its inhibition is associated with decreased fat absorption. CES1 is present at lower levels in the gut than CES2 (P23141), but predominates in the liver, where it is responsible for the hydrolysis of many aliphatic, aromatic and steroid esters. Hormone-sensitive lipase is also a relatively non-selective esterase associated with steroid ester hydrolysis and triglyceride metabolism, particularly in adipose tissue. Endothelial lipase is secreted from endothelial cells and regulates circulating cholesterol in high density lipoproteins
2004 program of study : tides
The summer of 2004 saw the GFD program tackle “Tides”. Myrl Hendershott (Scripps
Institution of Oceanography) gave a fabulous introduction to the subject in the first week
of the course, laying the foundations from astronomy and classical geophysical
fluid dynamics. In the second week, Chris Garrett (University of Victoria) admirably followed
up with recent developments on the subject, including the recent observations from satellite
altimetry, their implications to mixing and circulation, and even a memorable lecture on
the noble theme of how we might solve the world's energy crisis. The principal lectures
proved unusually popular this summer, and the seminar room at Walsh often overflowed in the
first two weeks.
Following on from the lectures, the seminar schedule of the summer covered in greater
detail the oceanographic issues with which researchers are actively grappling. We also
heard about related problems regarding atmospheric, planetary and stellar tides, together
with the usual mix of topics on GFD in general.
The summer once again featured a lecture for the general public in the Woods Hole
area. Carl Wunsch delivered a very well received lecture entitled “Climate Change Stories”,
in which he gave an impression of how scientists generally believe our climate is currently
changing, whilst simultaneously urging caution against some of the more outrageous and
exaggerated claims. The lecture was held at Lilly Auditorium, thanks to the hospitality
of the Marine Biology Laboratory. The reception following the lecture was enjoyed by
all.
Neil Balmforth and Stefan Llewellyn Smith acted as Co-Directors for the summer.
Janet Fields, Jeanne Fleming and Penny Foster provided the administrative backbone to
the Program, both during the summer and throughout the year beforehand. As always,
we were grateful to the Woods Hole Oceanographic Institution for the use of Walsh Cottage,
and Keith Bradley's solid service could not be overlooked. Shilpa Ghadge and Shreyas
Mandre are to be thanked for their part in comforting the fellows, developing the summer's
proceedings volume (available on the GFD web site) and for running the computer network.Funding was provided by the Office of Naval Research under Contract No. N00014-04-1-0157 and the National Science Foundation under Grant No. OCE-0325296
Hydrolases (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database
Listed in this section are hydrolases not accumulated in other parts of the Concise Guide, such as monoacylglycerol lipase and acetylcholinesterase. Pancreatic lipase is the predominant mechanism of fat digestion in the alimentary system; its inhibition is associated with decreased fat absorption. CES1 is present at lower levels in the gut than CES2 (P23141), but predominates in the liver, where it is responsible for the hydrolysis of many aliphatic, aromatic and steroid esters. Hormone-sensitive lipase is also a relatively non-selective esterase associated with steroid ester hydrolysis and triglyceride metabolism, particularly in adipose tissue. Endothelial lipase is secreted from endothelial cells and regulates circulating cholesterol in high density lipoproteins
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