2,939 research outputs found
Prediction of nocturia in live alone elderly using unobtrusive in-home sensors
iCity Lab; SHINESeniors; National Research Foundation (NRF) Singapore under the Land and Livability National Innovation Challenge (L2NIC
SU(3) Quantum Interferometry with single-photon input pulses
We develop a framework for solving the action of a three-channel passive
optical interferometer on single-photon pulse inputs to each channel using
SU(3) group-theoretic methods, which can be readily generalized to higher-order
photon-coincidence experiments. We show that features of the coincidence plots
vs relative time delays of photons yield information about permanents,
immanants, and determinants of the interferometer SU(3) matrix
Doping influence of spin dynamics and magnetoelectric effect in hexagonal YLuMnO
We use inelastic neutron scattering to study spin waves and their correlation
with the magnetoelectric effect in YLuMnO. In the undoped
YMnO and LuMnO, the Mn trimerization distortion has been suggested to
play a key role in determining the magnetic structure and the magnetoelectric
effect. In YLuMnO, we find a much smaller in-plane
(hexagonal -plane) single ion anisotropy gap that coincides with a weaker
in-plane dielectric anomaly at . Since both the smaller in-plane
anisotropy gap and the weaker in-plane dielectric anomaly are coupled to a
weaker Mn trimerization distortion in YLuMnO comparing to
YMnO and LuMnO, we conclude that the Mn trimerization is responsible
for the magnetoelectric effect and multiferroic phenomenon in
YLuMnO.Comment: 5 pages, 5 figure
A brief haemophilia pain coping questionnaire
Development and psychometric assessment of a questionnaire measuring pain coping for people with haemophiliaPain coping strategies are important influences on outcomes among people with painful chronic conditions. The pain coping strategies questionnaire (CSQ) was reviously adapted for sickle cell disease and haemophilia, but those versions have 80 items, and a briefer version with similar psychometric properties would facilitate research on pain coping. The full-length haemophilia-adapted CSQ, plus measures of pain frequency and intensity, pain acceptance, pain readiness to change, and health-related quality of life were completed by 190 men with haemophilia. Items were selected for a 27-item short form, which was completed 6 months later by 129 (68%) participants. Factor structure, reliability and concurrent validity were the same in the long and short forms. For the short form, internal reliabilities of the three composite scales were 0.86 for negative thoughts, 0.80 for active coping and 0.76 for passive adherence. Test–retest reliabilities were 0.73 for negative thoughts, 0.70 for active coping and 0.64 for passive adherence. Negative thoughts were associated with less readiness to change, less acceptance of pain and more impaired health-related quality of life, whereas active coping was associated with greater readiness to change and more acceptance of pain. The short form is a convenient brief measure of pain coping with good psychometric properties, and could be used to extend research on pain coping in haemophilia
Generalized multi-photon quantum interference
Non-classical interference of photons lies at the heart of optical quantum
information processing. This effect is exploited in universal quantum gates as
well as in purpose-built quantum computers that solve the BosonSampling
problem. Although non-classical interference is often associated with perfectly
indistinguishable photons this only represents the degenerate case, hard to
achieve under realistic experimental conditions. Here we exploit tunable
distinguishability to reveal the full spectrum of multi-photon non-classical
interference. This we investigate in theory and experiment by controlling the
delay times of three photons injected into an integrated interferometric
network. We derive the entire coincidence landscape and identify transition
matrix immanants as ideally suited functions to describe the generalized case
of input photons with arbitrary distinguishability. We introduce a compact
description by utilizing a natural basis which decouples the input state from
the interferometric network, thereby providing a useful tool for even larger
photon numbers
Cutinase from Amycolatopsis mediterannei: marked activation and stabilisation in Deep Eutectic Solvents
Amycolatopsis mediterranei cutinase (AmCut) has potential biocatalytic applications in plastics degradation and ester synthesis. Deep Eutectic Solvents (DES) are next generation biodegradable solvents for biocatalysis. However, the behaviour of cutinase enzymes in DES is little studied. Herein, we examine the effect of selected DES, and their components, on AmCut activity and stability. Low amounts (10% v/v) of DES (choline chloride:glycerol; 1:1 mole ratio) caused striking activation of AmCut (over 2-fold). Further examination showed that the choline chloride component of DES caused the observed activation. This is the first report of activation of a cutinase by a small molecule. At higher concentrations (50% v/v), DES composed of a choline chloride with glycerol as hydrogen bond donor dramatically increased the thermostability of AmCut - the enzyme lost no activity after incubation at 50oC for 2 hours. The biotechnological utility and physiological relevance of choline chloride activation and stabilisation is discussed
Extracellular secretion of a cutinase with polyester-degrading potential by E. coli using a novel signal peptide from Amycolatopsis mediterranei
Recent studies in this laboratory showed that an extracellular cutinase from A. mediterranei (AmCut) was able to degrade the plastics polycaprolactone and polybutylene succinate. Such plastics can be slow to degrade in soils due to a lack of efficient polyester degrading organisms. AmCut also showed potential for the biocatalytic synthesis of esters by reverse hydrolysis.
The gene for AmCut has an upstream leader sequence whose transcript is not present in the purified enzyme. In this study, we show using predictive modelling, that this sequence codes for an N-terminal signal peptide that directs transmembrane expression via the Sec secretion pathway.
E. coli is a useful host for recombinant enzymes used in biocatalysis due to the ease of genetic manipulation in this organism, which allows tuning of enzymes for specific applications, by mutagenesis. When a truncated AmCut gene (lacking its signal peptide) was expressed in E. coli, all cutinase activity was observed in the cytosolic fraction. However, when AmCut was expressed in E. coli along with its native signal peptide, cutinase activity was observed in the periplasmic space and in the culture medium. This finding revealed that the native signal peptide of a Gram-positive organism (A. mediterranei) was being recognised by the Gram-negative (E. coli) Sec transmembrane transport system. AmCut was transported into E. coli’s periplasmic space from where it was released into the culture medium. Although the periplasmic targeting was surprising, it is not unprecedented due to the conservation of the Sec pathway across species. It was more surprising that AmCut was secreted from the periplasmic space into the culture medium. This suggests that extracellular AmCut translocation across the E. coli outer membrane may involve non-classical secretion pathways. This tuneable recombinant E. coli expressing extracellular AmCut may be useful for degradation of polyester substrates in the environment; this and other applications are discussed
An Extracellular Lipase from Amycolatopsis Mediterannei is a Cutinase with Plastic Degrading Activity
An extracellular lipase from Amycolatopsis mediteranei (AML) with potential applications in process biotechnology was recently cloned and examined in this laboratory. In the present study, the 3D structure of AML was elucidated by comparative modelling. AML lacked the ‘lid’ structure observed in most true lipases and shared similarities with plastic degrading enzymes. Modelling and substrate specificity studies showed that AML was a cutinase with a relatively exposed active site and specificity for medium chain fatty acyl moieties.
AML rapidly hydrolysed the aliphatic plastics poly(ε-caprolactone) and poly(1,4-butylene succinate) extended with 1,6-diisocyanatohexane under mild conditions. These plastics are known to be slow to degrade in landfill. Poly(L-lactic acid) was not hydrolysed by AML, nor was the aromatic plastic Polyethylene Terephthalate (PET). The specificity of AML is partly explained by active site topology and analysis reveals that minor changes in the active site region can have large effects on substrate preference. These findings show that extracellular Amycolatopsis enzymes are capable of degrading a wider range of plastics than is generally recognised. The potential for application of AML in the bioremediation of plastics is discussed
Solvent stable microbial lipases: Current understanding and biotechnological applications
Objective: This review examines on our current understanding of microbial lipase solvent tolerance, with a specific focus on the molecular strategies employed to improve lipase stability in a non-aqueous environment.
Results: It provides an overview of known solvent tolerant lipases and of approaches to improving solvent stability such as; enhancing stabilising interactions, modification of residue flexibility and surface charge alteration. It shows that judicious selection of lipase source supplemented by appropriate enzyme stabilisation, can lead to a wide application spectrum for lipases.
Conclusion: Organic solvent stable lipases are, and will continue to be, versatile and adaptable biocatalytic workhorses commonly employed for industrial applications in the food, pharmaceutical and green manufacturing industries
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