215 research outputs found
First-principles theory of the luminescence lineshape for the triplet transition in diamond NV centre
In this work we present theoretical calculations and analysis of the vibronic
structure of the spin-triplet optical transition in diamond nitrogen-vacancy
centres. The electronic structure of the defect is described using accurate
first-principles methods based on hybrid functionals. We devise a computational
methodology to determine the coupling between electrons and phonons during an
optical transition in the dilute limit. As a result, our approach yields a
smooth spectral function of electron-phonon coupling and includes both
quasi-localized and bulk phonons on equal footings. The luminescence lineshape
is determined via the generating function approach. We obtain a highly accurate
description of the luminescence band, including all key parameters such as the
Huang-Rhys factor, the Debye-Waller factor, and the frequency of the dominant
phonon mode. More importantly, our work provides insight into the vibrational
structure of nitrogen vacancy centres, in particular the role of local modes
and vibrational resonances. In particular, we find that the pronounced mode at
65 meV is a vibrational resonance, and we quantify localization properties of
this mode. These excellent results for the benchmark diamond nitrogen-vacancy
centre provide confidence that the procedure can be applied to other defects,
including alternative systems that are being considered for applications in
quantum information processing
Organ-specific effects of oxygen and carbogen gas inhalation on tissue longitudinal relaxation times
Acetylcholine receptors (muscarinic) (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database
Muscarinic acetylcholine receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Muscarinic Acetylcholine Receptors [45]) are GPCRs of the Class A, rhodopsin-like family where the endogenous agonist is acetylcholine. In addition to the agents listed in the table, AC-42, its structural analogues AC-260584 and 77-LH-28-1, N-desmethylclozapine, TBPB and LuAE51090 have been described as functionally selective agonists of the M1 receptor subtype via binding in a mode distinct from that utilized by non-selective agonists [243, 242, 253, 155, 154, 181, 137, 11, 230]. There are two pharmacologically characterised allosteric sites on muscarinic receptors, one defined by it binding gallamine, strychnine and brucine, and the other defined by the binding of KT 5720, WIN 62,577, WIN 51,708 and staurosporine [161, 162]
Acetylcholine receptors (muscarinic) in GtoPdb v.2021.3
Muscarinic acetylcholine receptors (mAChRs) (nomenclature as agreed by the NC-IUPHAR Subcommittee on Muscarinic Acetylcholine Receptors [50]) are activated by the endogenous agonist acetylcholine. All five (M1-M5) mAChRs are ubiquitously expressed in the human body and are therefore attractive targets for many disorders. Functionally, M1, M3, and M5 mAChRs preferentially couple to Gq/11 proteins, whilst M2 and M4 mAChRs predominantly couple to Gi/o proteins. Both agonists and antagonists of mAChRs are clinically approved drugs, including pilocarpine for the treatment of elevated intra-ocular pressure and glaucoma, and atropine for the treatment of bradycardia and poisoning by muscarinic agents such as organophosphates
Acetylcholine receptors (muscarinic) in GtoPdb v.2023.1
Muscarinic acetylcholine receptors (mAChRs) (nomenclature as agreed by the NC-IUPHAR Subcommittee on Muscarinic Acetylcholine Receptors [53]) are activated by the endogenous agonist acetylcholine. All five (M1-M5) mAChRs are ubiquitously expressed in the human body and are therefore attractive targets for many disorders. Functionally, M1, M3, and M5 mAChRs preferentially couple to Gq/11 proteins, whilst M2 and M4 mAChRs predominantly couple to Gi/o proteins. Both agonists and antagonists of mAChRs are clinically approved drugs, including pilocarpine for the treatment of elevated intra-ocular pressure and glaucoma, and atropine for the treatment of bradycardia and poisoning by muscarinic agents such as organophosphates. Of note, it has been observed that mAChRs dimerise reversibly [134] and that dimerisation/oligomerisation can be affected by ligands [183, 196]
Evolutionary connectionism: algorithmic principles underlying the evolution of biological organisation in evo-devo, evo-eco and evolutionary transitions
The mechanisms of variation, selection and inheritance, on which evolution by natural selection depends, are not fixed over evolutionary time. Current evolutionary biology is increasingly focussed on understanding how the evolution of developmental organisations modifies the distribution of phenotypic variation, the evolution of ecological relationships modifies the selective environment, and the evolution of reproductive relationships modifies the heritability of the evolutionary unit. The major transitions in evolution, in particular, involve radical changes in developmental, ecological and reproductive organisations that instantiate variation, selection and inheritance at a higher level of biological organisation. However, current evolutionary theory is poorly equipped to describe how these organisations change over evolutionary time and especially how that results in adaptive complexes at successive scales of organisation (the key problem is that evolution is self-referential, i.e. the products of evolution change the parameters of the evolutionary process). Here we first reinterpret the central open questions in these domains from a perspective that emphasises the common underlying themes. We then synthesise the findings from a developing body of work that is building a new theoretical approach to these questions by converting well-understood theory and results from models of cognitive learning. Specifically, connectionist models of memory and learning demonstrate how simple incremental mechanisms, adjusting the relationships between individually-simple components, can produce organisations that exhibit complex system-level behaviours and improve the adaptive capabilities of the system. We use the term “evolutionary connectionism” to recognise that, by functionally equivalent processes, natural selection acting on the relationships within and between evolutionary entities can result in organisations that produce complex system-level behaviours in evolutionary systems and modify the adaptive capabilities of natural selection over time. We review the evidence supporting the functional equivalences between the domains of learning and of evolution, and discuss the potential for this to resolve conceptual problems in our understanding of the evolution of developmental, ecological and reproductive organisations and, in particular, the major evolutionary transitions
A Prospective Study of Pravastatin in the Elderly at Risk (PROSPER): Screening Experience and Baseline Characteristics
BACKGROUND: PROSPER was designed to investigate the benefits of treatment with pravastatin in elderly patients for whom a typical doctor might consider the prescription of statin therapy to be a realistic option. METHODS: The PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) is a randomised, double blind, placebo-controlled trial to test the hypothesis that treatment with pravastatin (40 mg/day) will reduce the risk of coronary heart disease death, non-fatal myocardial infarction, and fatal or non-fatal stroke in elderly men and women with pre-existing vascular disease or with significant risk of developing this condition. RESULTS: In Scotland, Ireland, and the Netherlands, 23,770 individuals were screened, and 5,804 subjects (2,804 men and 3,000 women), aged 70 to 82 years (average 75 years) and with baseline cholesterol 4.0–9.0 mmol/l, were randomised. Randomised subjects had similar distributions with respect to age, blood pressure, and body mass index when compared to the entire group of screenees, but had a higher prevalence of smoking, diabetes, hypertension, and a history of vascular disease. The average total cholesterol level at baseline was 5.4 mmol/l (men) and 6.0 mmol/l (women). CONCLUSIONS: Compared with previous prevention trials of cholesterol-lowering drugs, the PROSPER cohort is significantly older and for the first time includes a majority of women. The study, having achieved its initial goal of recruiting more than 5,500 elderly high-risk men and women, aims to complete all final subject follow-up visits in the first half of 2002 with the main results being available in the fourth quarter of 2002
Assessment of effectiveness measures in patients with schizophrenia initiated on risperidone long-acting therapy: the SOURCE study results
<p>Abstract</p> <p>Background</p> <p>To evaluate effectiveness outcomes in a real-world setting in patients with schizophrenia initiating risperidone long-acting therapy (RLAT).</p> <p>Methods</p> <p>This was a 24-month, multicenter, prospective, longitudinal, observational study in patients with schizophrenia who were initiated on RLAT. Physicians could change treatment during the study as clinically warranted. Data were collected at baseline and subsequently every 3 months up to 24 months. Effectiveness outcomes included changes in illness severity as measured by Clinical Global Impression-Severity (CGI-S) scale; functional scores as measured by Personal and Social Performance (PSP) scale, Global Assessment of Functioning (GAF), and Strauss-Carpenter Levels of Functioning (LOF); and health status (Medical Outcomes Survey Short Form-36 [SF-36]). Life-table methodology was used to estimate the cumulative probability of relapse over time. Adverse events were evaluated for safety.</p> <p>Results</p> <p>532 patients were enrolled in the study; 209 (39.3%) completed the 24-month study and 305 (57.3%) had at least 12 months of follow-up data. The mean (SD) age of patients was 42.3 (12.8) years. Most patients were male (66.4%) and either Caucasian (60.3%) or African American (23.7%). All changes in CGI-S from baseline at each subsequent 3-month follow-up visit were statistically significant (<it>p </it>< .0001), indicating improvement in disease severity. Improvements were also noted for the PSP, GAF, and total LOF, indicating improvement in daily functioning and health outcome.</p> <p>Conclusions</p> <p>Patients with schizophrenia who were initiated on RLAT demonstrated improvements in measures of effectiveness within 3 months, which persisted over 24 months.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00246194">NCT00246194</a></p
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