5,218 research outputs found
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Metaldehyde removal from drinking water by adsorption onto filtration media: mechanisms and optimisation
Trace micropollutants should be removed during drinking water production without increasing the disinfection-by-product formation potential or energy demand of the treatment process. We demonstrate the efficacy of different filtration media to remove metaldehyde through controlled batch experiments on water augmented with metaldehyde. Equilibrium concentrations of metaldehyde and surrogate organics were successfully described by the Freundlich isotherm. Metaldehyde can be attenuated to varying degrees with activated carbon and sand with an active and inactive biofilm with kf values ranging from 0.006ā0.3 (mg gā1)(L mgā1)1/n. The presence of the active biofilm improved metaldehyde adsorption by sand media, due to additional biosorption mechanisms, a greater surface area or biodegradation. Baseline levels of competing natural organic matter surrogates (NOM) reduced overall adsorption efficacy but increasing concentrations of NOM did not impact metaldehyde removal efficacy in a significant way. Biological activated carbon was identified as the most suitable adsorbent of metaldehyde (94% removal) but sand with an acclimated biofilm was capable of acting as a bio-adsorbent of metaldehyde even under environmentally relevant concentrations (41% adsorption from 0.002.5 mg Lā1). Moreover, we observed that thermal hydrolysis of metaldehyde occurred at 60 Ā°C, suggesting that thermal regeneration of GAC for this pesticide was possible at relatively low temperatures. Biological adsorption and thermal hydrolysis approaches presented herein offered a way forward to increase efficiency and cost effectiveness of existing treatments for metaldehyde
Sleep disturbance and serum ferritin levels associate with high impulsivity and impulse control disorders in male Parkinson\u27s Disease patients
Impulse control disorders (ICDs) occur in a subset of Parkinsonās disease (PD) patients on dopaminergic medications however there are currently no reliable markers to identify patients at risk. Sleep disturbances are more common in patients with an ICD. Serum ferritin levels have been associated with PD disease stage and progression, but have not previously been associated with impulsivity levels. The objective of this study was to determine if serum ferritin levels and sleep disturbance are associated with high traits of impulsivity and ICD in a cohort of PD patients attending a movement disorders clinic. This study assessed impulsiveness in 87 PD patients using the Barratt Impulsiveness Scale. Severity of sleep disturbance was determined using the sleep-related items of the MDS-UPDRS. Serum ferritin, iron and transferrin levels were measured in patients, as well as 36 age-matched healthy controls. Serum ferritin levels were significantly elevated in male PD patients in the high impulsivity group compared to patients in the low (p=.022) and normal range groups (p=.024) and showed a linear increase across the three groups. Sleep disturbance also demonstrated a linear trend, which was most severe in the high impulsivity group (p=.030). A subgroup of 11 male PD patients who fulfilled the DSM-5 criteria for an ICD had significantly higher ferritin levels and more severe sleep disturbance when compared with the remaining male PD cohort. Serum ferritin levels and sleep disturbance severity are highlighted as potential markers for abnormal impulsivity and ICD in PD patients
Extended Timed Up and Go assessment as a clinical indicator of cognitive state in Parkinson\u27s disease
Objective: To evaluate a modified extended Timed Up and Go (extended-TUG) assessment against a panel of validated clinical assessments, as an indicator of Parkinsonās disease (PD) severity and cognitive impairment.
Methods: Eighty-seven participants with idiopathic PD were sequentially recruited from a Movement Disorders Clinic. An extended-TUG assessment was employed which required participants to stand from a seated position, walk in a straight line for 7 metres, turn 180 degrees and then return to the start, in a seated position. The extended-TUG assessment duration was correlated to a panel of clinical assessments, including the Unified Parkinsonās Disease Rating Scale (MDS-UPDRS), Quality of Life (PDQ-39), Scales for Outcomes in Parkinsonās disease (SCOPA-Cog), revised Addenbrookeās Cognitive Index (ACE-R) and Barrattās Impulsivity Scale 11 (BIS-11).
Results: Extended-TUG time was significantly correlated to MDS-UPDRS III score and to SCOPA-Cog, ACE-R (p\u3c0.001) and PDQ-39 scores (p\u3c0.01). Generalized linear models determined the extended-TUG to be a sole variable in predicting ACE-R or SCOPA-Cog scores. Patients in the fastest extended-TUG tertile were predicted to perform 8.3 and 13.4 points better in the SCOPA-Cog and ACE-R assessments, respectively, than the slowest group. Patients who exceeded the dementia cut-off scores with these instruments exhibited significantly longer extended-TUG times.
Conclusions: Extended-TUG performance appears to be a useful indicator of cognition as well as motor function and quality of life in PD, and warrants further evaluation as a first line assessment tool to monitor disease severity and response to treatment. Poor extended-TUG performance may identify patients without overt cognitive impairment form whom cognitive assessment is needed
A Hartree-Fock Study of Persistent Currents in Disordered Rings
For a system of spinless fermions in a disordered mesoscopic ring,
interactions can give rise to an enhancement of the persistent current by
orders of magnitude. The increase in the current is associated with a charge
reorganization of the ground state. The interaction strength for which this
reorganization takes place is sample-dependent and the log-averages over the
ensemble are not representative. In this paper we demonstrate that the
Hartree-Fock method closely reproduces results obtained by exact
diagonalization. For spinless fermions subject to a short-range Coulomb
repulsion U we show that due to charge reorganization the derivative of the
persistent current is a discontinuous function of U. Having established that
the Hartree-Fock method works well in one dimension, we present corresponding
results for persistent currents in two coupled chains.Comment: 4 pages, 6 figures, Submitted to Phys. Rev.
Entanglement between static and flying qubits in quantum wires
A weakly bound electron in a semiconductor quantum wire is shown to become
entangled with an itinerant electron via the coulomb interaction. The degree of
entanglement and its variation with energy of the injected electron, may be
tuned by choice of spin and initial momentum. Full entanglement is achieved
close to energies where there are spin-dependent resonances. Possible
realisations of related device structures are discussed
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Smart biomimetic construction materials for next generation infrastructure
The resilience of building and civil engineering structures is typically associated with the design of individual elements such that they have sufficient capacity or potential to react in an appropriate manner to adverse events. Traditionally this has been achieved by using ārobustā design procedures that focus on defining safety factors for individual adverse events and providing redundancy. As such, construction materials are designed to meet a prescribed specification; material degradation is viewed as inevitable and mitigation necessitates expensive maintenance regimes; ~Ā£40 billion/year is spent in the UK on repair and maintenance of existing, mainly concrete, structures. More recently, based on a better understanding and knowledge of microbiological systems, materials that have the ability to adapt and respond to their environment have been developed. This fundamental change has the potential to facilitate the creation of a wide range of āsmartā materials and intelligent structures, including both autogenous and autonomic selfāhealing materials and adaptable, selfāsensing and selfārepairing structures, which can transform our infrastructure by embedding resilience in the materials and components of these structures so that rather than being defined by individual events, they can evolve over their lifespan. We therefore advocate that next generation infrastructure will include next generation infrastructure materials based on smart biomimetic construction materials. This paper presents details of the national consortium that is leading international efforts in the development of those next generation infrastructure materials. It presents details of the work done to date, over the past three years, as part of the EPSRC funded project Materials for Life and the plans for work to be done over the next five years as part of a follow-on Programme grant: Resilient Materials for Life
Investigation of Proton-Proton Short-Range Correlations via the (12)C(e,eā²pp) Reaction
We investigated simultaneously the 12C(e,eā²p) and 12C(e,eā²pp) reactions at Q2=2āā(GeV/c)2, xB=1.2, and in an (e, eā²p) missing-momentum range from 300 to 600āāMeV/c. At these kinematics, with a missing momentum greater than the Fermi momentum of nucleons in a nucleus and far from the delta excitation, short-range nucleon-nucleon correlations are predicted to dominate the reaction. For (9.5Ā±2)% of the 12C(e,eā²p) events, a recoiling partner proton was observed back-to-back to the 12C(e,eā²p) missing-momentum vector, an experimental signature of correlations
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