Bimatoprost (Lumigan™) is a pharmacologically unique and highly efficacious ocular hypotensive agent. It appears to mimic the activity of a newly discovered family of fatty acid amides, termed
...prostamides. One biosynthetic route to the prostamides involves anandamide as the precursor. Bimatoprost pharmacology has been extensively characterized by binding and functional studies at more than 100 drug targets, which comprise a diverse variety of receptors, ion channels, and transporters. Bimatoprost exhibited no meaningful activity at receptors known to include antiglaucoma drug targets as follows: adenosine (A
1–3), adrenergic (α
1, α
2, β
1, β
2), cannabinoid (CB
1, CB
2), dopamine (D
1–5), muscarinic (M
1–5), prostanoid (DP, EP
1–4, FP, IP, TP), and serotonin (5HT
1–7). Bimatoprost does, however, exhibit potent inherent pharmacological activity in the feline iris sphincter preparation, which is prostamide-sensitive. Bimatoprost also resembles the prostamides in that it is a potent and highly efficacious ocular hypotensive agent. A single dose of bimatoprost markedly reduces intraocular pressure in dogs and laser-induced ocular hypertensive monkeys. Decreases in intraocular pressure are well maintained for at least 24 hr post-dose. Human studies have demonstrated that systemic exposure to bimatoprost is low and that accumulation does not occur. The sclera is the preferred route of accession to the eye. The high scleral permeability coefficient Papp is a likely contributing factor to the rapid onset and long-acting ocular hypotensive profile of bimatoprost.
We report low-temperature thermal expansion measurements on the bilayer ruthenate Sr3Ru2O7 as a function of magnetic field applied perpendicular to the ruthenium-oxide planes. The field dependence of ...the c-axis expansion coefficient indicates the accumulation of entropy close to 8 T, related to an underlying quantum critical point. The latter is masked by two first-order metamagnetic transitions which bound a regime of enhanced entropy. Outside this region the singular thermal expansion behavior is compatible with the predictions of the itinerant theory for a two-dimensional metamagnetic quantum critical end point.
Foreign accent syndrome (FAS) is a rare disorder characterized by the emergence of a perceived foreign accent following brain damage. The symptomotology, functional bases, and neural substrates of ...this disorder are still being elucidated. In this case study, acoustic analyses were performed on the speech of a 46-year old monolingual female who presented with FAS of unknown aetiology. The patient had a pseudo-accent frequently described as 'Swedish' or 'Eastern European'. Stop consonant VOT, consonant burst spectra and duration, vowel durations, formant frequencies, and trajectories were analysed, along with prosodic cues for lexical stress assignment and sentence-level intonation. Results indicated VOT values were generally preserved, while there was a strong tendency to realize the English alveolar flap as a full stop, and to produce flaps that had greater-than-normal closure durations. The spectral properties of the patient's vowels resembled those of normal talkers (with the possible exceptions of decreased F1 values for i and slight differences in formant dynamics for u , o , i , and ). However, vowel durations were relatively long, contributing to exaggerated tense lax contrasts. Token-to-token variability in vowel production was slightly higher than normal for duration, but not for formant frequency values. Lexical stress assignment was inaccurate and highly variable (with similar problems noted for non-speech materials), and sentence level intonation showed occasional deviations from typical American English patterns. For this patient, an underlying timing rhythm difficulty appeared responsible for the range of segmental and suprasegmental changes leading to the impression of a foreign accent.
Aerospace Medicine Clinic Garst, M.D., M.P.H., Geoffrey; Asuquo, and Rachel
Aerospace medicine and human performance,
05/2021, Letnik:
92, Številka:
7
Journal Article
Magnetic soliton layers in epitaxial MnSi Causer, G. L.; Azhar, M.; Hesjedal, T. ...
Acta crystallographica. Section A, Foundations and advances,
08/2023, Letnik:
79, Številka:
a2
Journal Article
At a generic quantum critical point, the thermal expansion alpha is more singular than the specific heat c(p). Consequently, the "Grüneisen ratio," Gamma=alpha/c(p), diverges. When scaling applies, ...Gamma approximately T(-1/(nu z)) at the critical pressure p=p(c), providing a means to measure the scaling dimension of the most relevant operator that pressure couples to; in the alternative limit T-->0 and p not equal p(c), Gamma approximately 1/(p-p(c)) with a prefactor that is, up to the molar volume, a simple universal combination of critical exponents. For a magnetic-field driven transition, similar relations hold for the magnetocaloric effect (1/T) partial differential T/ partial differential H|(S). Finally, we determine the corrections to scaling in a class of metallic quantum critical points.
The interplay of electronic and structural degrees of freedom in solids is a topic of intense research. More than 60 years ago, Lifshitz discussed a counterintuitive possibility: lattice softening ...driven by conduction electrons at topological Fermi surface transitions. The effect that he predicted, however, was small and has not been convincingly observed. Using a piezo-based uniaxial pressure cell to tune the ultraclean metal strontium ruthenate while measuring the stress-strain relationship, we reveal a huge softening of the Young’s modulus at a Lifshitz transition of a two-dimensional Fermi surface and show that it is indeed driven entirely by the conduction electrons of the relevant energy band.
Editor’s summary
In solid state materials, changes in the crystal lattice are often accompanied by changes in the electronic system. Whether the lattice or the electrons is the primary driver of a transition may, however, be difficult to ascertain. Noad
et al
. measured the Young’s modulus in the extremely clean material Sr
2
RuO
4
as it underwent an electronic (Lifshitz) transition. The researchers found a large drop in the Young’s modulus at the transition, suggesting that conduction electrons drive a nonlinear elastic response in this material. —Jelena Stajic
Measurements of the Young’s modulus revealed a lattice softening much larger than that predicted by Lifshitz.
Background: Previous studies have suggested that visual augmented feedback provided by electromagnetic articulography (EMA) helps persons with apraxia of speech (AOS) recover speech motor control ...following stroke (e.g., Katz et al.,
2007
). However, the data are few, both in terms of the variety of participants and the speech motor targets investigated.
Aims: This study was designed to determine whether EMA supplied feedback improves articulatory accuracy in an adult with acquired AOS. We also examined whether reduced feedback frequency results in (1) decreased performance during acquisition and (2) enhanced maintenance and generalisation of the targeted behaviours.
Methods & Procedures: A multiple-baseline across-behaviours design was used to assess the efficacy of this treatment for an individual with AOS. Over a 27-week period, the participant received visual feedback provided by an EMA system for treatment of three groups of speech motor targets (SMTs): /j/, /θ/, and /t∫ / with various following VCs. The consonant clusters /br/ and /sw/ served as untreated controls. Frequency of feedback scheduling was 100% for /j/ and /t∫ /, and 50% for /θ/.
Outcomes & Results: For the first group of SMTs treated, /j/, there was acquisition for 4/5 trained words. These were maintained post-treatment and at the long-term probe. Improved performance and maintenance were also noted for 5/8 untreated stimuli, with maintenance shown for most of these words by 1 month post-treatment. The next treated SMT, /θ/, showed acquisition for all five treated items. Two of these five targets were maintained one month post-treatment. All three untreated /θ/ probes showed generalisation, with two of these showing maintenance post-treatment. The third treated group of SMTs, /t∫/, showed improved performance for all of the five treated words. However, these gains could only be attributed to /t∫/ treatment for three of the five words. Two treated items appeared well maintained at 1 month post-treatment. Generalisation and maintenance were also noted for all six untreated /t∫ / words. However, generalisation from previously treated /j/ and /t∫/ targets was involved in their improved performance. The untrained (control) word data suggested that the gains noted for treated items did not result from across-the-board improvement or unassisted recovery. There were no consistent differences corresponding with low- versus high-frequency feedback conditions.
Conclusions: Augmented kinematic feedback provided by an EMA system improved production for some, but not all, treated targets. Generalisation to untreated probes was also evident. Predictions concerning the effects of feedback frequency on the acquisition, maintenance, and transfer of trained behaviours were not supported.
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