3,314 research outputs found
Classification of the mechanomyogram signal using a wavelet packet transform and singular value decomposition
Title on authorās file: Classification of mechanomyogram signal using wavelet packet transform and singular value decomposition for multifunction prosthesis control2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
Continuous monitoring of electromyography (EMG), mechanomyography (MMG), sonomyography (SMG) and torque output during ramp and step isometric contractions
2010-2011 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
Palgol: A High-Level DSL for Vertex-Centric Graph Processing with Remote Data Access
Pregel is a popular distributed computing model for dealing with large-scale
graphs. However, it can be tricky to implement graph algorithms correctly and
efficiently in Pregel's vertex-centric model, especially when the algorithm has
multiple computation stages, complicated data dependencies, or even
communication over dynamic internal data structures. Some domain-specific
languages (DSLs) have been proposed to provide more intuitive ways to implement
graph algorithms, but due to the lack of support for remote access --- reading
or writing attributes of other vertices through references --- they cannot
handle the above mentioned dynamic communication, causing a class of Pregel
algorithms with fast convergence impossible to implement.
To address this problem, we design and implement Palgol, a more declarative
and powerful DSL which supports remote access. In particular, programmers can
use a more declarative syntax called chain access to naturally specify dynamic
communication as if directly reading data on arbitrary remote vertices. By
analyzing the logic patterns of chain access, we provide a novel algorithm for
compiling Palgol programs to efficient Pregel code. We demonstrate the power of
Palgol by using it to implement several practical Pregel algorithms, and the
evaluation result shows that the efficiency of Palgol is comparable with that
of hand-written code.Comment: 12 pages, 10 figures, extended version of APLAS 2017 pape
Estimation of wrist angle from sonomyography using support vector machine and artificial neural network models
2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
Not quite a doctor, but should I help? A qualitative exploration of medical students' attitudes towards responding to medical emergencies that occur in the public domain
Objective To explore medical studentsā views on and experiences of responding to out-of-hospital medical emergencies.
Setting University College London (UCL).
Participants 11 UCL Medical School students.
Study design Qualitative.
Methods and outcome measures We carried out 11 one-to-one semistructured interviews, with participant validation and reflective work. The data were analysed using thematic analysis.
Results Three core themes were identified. (1) āWe Did Debate a Bit: Should We Go? Should We Not?āāStudentsā decisions to respond were based on the appearance of the casualty; the presence and actions of bystanders; witnessing the incident; self-perceived competence, confidence and knowledge; and personal experiences and feelings associated with medical emergencies. (2) āIt Would Represent the Medical Profession Well if We Did Step In and HelpāāStudents felt that they had an ethical and/or professional duty to help. (3) āNo One Should Die Because of a Lack ofā¦ Basic Life-Saving TechniquesāāStudents felt that medical school training alone had not sufficiently prepared them to respond to out-of-hospital medical emergencies. Improvements to training were suggested: integrating first aid/responseātraining into the horizontal (systems-based) modules; teaching both common and less common medical emergencies and presentations; training that is led by experienced first responders and that increases studentsā exposure to out-of-hospital medical emergencies; and providing more revision training sessions.
Conclusions Students felt that medical school training could be improved to better prepare them for responding to out-of-hospital medical emergencies, and wanted clarification on whether or not they have an ethical and/or professional duty to help. Further mixed-methods research using a larger sample needs to be carried out to confirm whether findings are transferable to other UK medical schools
Multiple sites and actions of gabapentin-induced relief of ongoing experimental neuropathic pain
Gabapentin is a first-line therapy for neuropathic pain but its mechanisms and sites of action
remain uncertain. We investigated gabapentin-induced modulation of neuropathic pain following
spinal nerve ligation (SNL) in rats. Intravenous or intrathecal gabapentin reversed evoked
mechanical hypersensitivity, produced conditioned place preference (CPP) and dopamine release
in the nucleus accumbens (NAc) selectively in SNL rats. Spinal gabapentin also significantly
inhibited dorsal horn wide dynamic range (WDR) neuronal responses to a range of evoked stimuli
in SNL rats. In contrast, gabapentin microinjected bilaterally into the rostral anterior cingulate
cortex (rACC), produced CPP and elicited NAc dopamine release selectively in SNL rats but did
not reverse tactile allodynia and had marginal effects on WDR neuronal activity. Moreover,
blockade of endogenous opioid signaling in the rACC prevented intravenous gabapentin-induced
CPP and NAc dopamine release but failed to block its inhibition of tactile allodynia. Gabapentin
therefore can potentially act to produce its pain relieving effects by (a) inhibition of injury-induced
spinal neuronal excitability, evoked hypersensitivity and ongoing pain and (b) selective supraspinal
modulation of affective qualities of pain, without alteration of reflexive behaviors. Consistent with
previous findings of pain relief from non-opioid analgesics, gabapentin requires engagement of
rACC endogenous opioid circuits and downstream activation of mesolimbic reward circuits
reflected in learned pain motivated behaviors. These findings support the partial separation of
sensory and affective dimensions of pain in this experimental model and suggest that modulation
of affective-motivational qualities of pain may be the preferential mechanism of gabapentinās
analgesic effects in patients
Immunomodulatory Potential of Patchouli Alcohol Isolated from Pogostemon cablin (Blanco) Benth (Lamiaceae) in Mice
Purpose: To isolate and purify patchouli alcohol (PA), a tricyclic sesquiterpene constituent of Pogostemon cablin, and investigate its immunomodulatory potential in Kunming mice.Methods: PA was prepared from an ethanol aqueous extract of P. cablin by silica gel column chromatography, and further purified by crystallization using n-hexane. Purity was assessed by analytical gas chromatography (GC) and confirmation of chemical structure performed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The effect of PA from Pogostemon cablin on immunological function was studied by macrophage phagocytosis, immune organ index, serum immunoglobulin level and delayed typeĀ hypersensitivity (DTH) in mice that were administered orally doses of 20, 40 and 80 mg/kg.Results: The purity of PA was 99.3%. The oral administration of PA (40, or 80 mg/kg body weight) significantly increased the phagocytic index (p < 0.05), compared with prednisone acetate (PR) group. Administration of PA (80 mg/kg) boosted the production of circulating serum IgM (0.081 Ā± 0.010) and IgG (1.296 Ā± 0.120), while IgM and IgG in PR group was 0.069 Ā± 0.011 (p < 0.01) and 1.180 Ā± 0.070 (p < 0.01) respectively. However, PA (20 mg/kg) treatment elicited significant decrease in DTH induced by 2, 4-dinitro-chlorobenzene (DNCB) in mice (1.03 Ā± 0.40, p < 0.05), in comparison to DNCB-induced group (1.67 Ā± 0.84 mg).Conclusion: These results suggest that PA has significant immunomodulatory properties which probably act by activating mononuclear phagocytic system, augmenting humoral immune response while suppressing cellular immune response.Keywords: Patchouli alcohol, Pogostemon cablin, Immunomodulatory, Phagocytic index, Macrophag
Synthesis and characterization of folate-poly(ethylene glycol) chitosan graft-polyethylenimine as a non-viral carrier for tumor-targeted gene delivery
The use of chitosan and chitosan derivatives for gene delivery is limited due to the low transfection efficiency and difficulty in transfecting into a variety of cell types, including some cancer cells overexpressing folate receptor (FRs). In order to solve this problem, folate (FA) and poly(ethylene glycol) (PEG) was conjugated to chitosan-graft-polyethylenimine (CHI-g-PEI) to enhance water-solubility and the transfection efficiency. In the present study, a cell specific targeting molecule FA was linked on PEG and then grafted the FA-PEG onto CHI-g-PEI. The FA-PEG-grafted CHI-g-PEI (FA-PEG-CHI-g-PEI) effectively condensed the plasmid DNA (pDNA) into nanoparticles with positive surface charge under the suitable nitrogen/phosphorus (N/P) ratio. In vitro, transfection efficiency of the FA-PEG-CHI-g-PEI /pDNA complex in 293T cells and LoVo cells (FRs over-expressing cell lines) increased with increasing N/P ratio under N/P = 15 and was more than 50%, but no significant difference in human lung carcinoma cells (A549) cells (FRs deficient cell lines). Importantly, in vivo luciferase expression showed that the efficiency of FA-PEG-CHI-g-PEI -mediated transfection (50 Ī¼g luciferase plasmid (pLuc), N/P ratio = 15) was comparable to that of adenovirus-mediated luciferase transduction (1 Ć 109 pfu) in melanomabearing mice. It was concluded that FA-PEG-CHI-g-PEI, which has improved transfection efficiency and FRs specificity in vitro and in vivo, may be useful in gene therapy.Key words: Folate poly(ethylene glycol)-chitosan-grafted-polyethylenimine (FA-PEG-CHI-g-PEI), gene transfection, non-virus vector, in vitro, in viv
Selective deficiencies in descending inhibitory modulation in neuropathic rats: implications for enhancing noradrenergic tone
Pontine noradrenergic neurones form part of a descending inhibitory system that influences spinal nociceptive processing. Weak or absent descending inhibition is a common feature of chronic pain patients. We examined the extent to which the descending noradrenergic system is tonically active, how control of spinal neuronal excitability is integrated into thalamic relays within sensory-discriminative projection pathways, and how this inhibitory control is altered after nerve injury. In vivo electrophysiology was performed in anaesthetised spinal nerveāligated (SNL) and sham-operated rats to record from wide dynamic range neurones in the ventral posterolateral thalamus (VPL). In sham rats, spinal block of Ī±2-adrenoceptors with atipamezole resulted in enhanced stimulus-evoked and spontaneous firing in the VPL, and produced conditioned place avoidance. However, in SNL rats, these conditioned avoidance behaviours were absent. Furthermore, inhibitory control of evoked neuronal responses was lost, but spinal atipamezole markedly increased spontaneous firing. Augmenting spinal noradrenergic tone in neuropathic rats with reboxetine, a selective noradrenergic reuptake inhibitor, modestly reinstated inhibitory control of evoked responses in the VPL but had no effect on spontaneous firing. By contrast, clonidine, an Ī±2 agonist, inhibited both evoked and spontaneous firing, and exhibited increased potency in SNL rats compared with sham controls. These data suggest descending noradrenergic inhibitory pathways are tonically active in sham rats. Moreover, in neuropathic states, descending inhibitory control is diminished, but not completely absent, and distinguishes between spontaneous and evoked neuronal activity. These observations may have implications for how analgesics targeting the noradrenergic system provide relief
Synthesis and characterization of hybrid organic-inorganic materials based on sulphonated polyamideimide and silica
The preparation of hybrid organicāinorganic
membrane materials based on a sulphonated polyamideimide
resin and silica filler has been studied. The method
allows the solāgel process to proceed in the presence of a
high molecular weight polyamideimide, resulting in well
dispersed silica nanoparticles (<50 nm) within the polymer
matrix with chemical bonding between the organic and
inorganic phases. Tetraethoxysilane (TEOS) was used as
the silica precursor and the organosilicate networks were
bonded to the polymer matrix via a coupling agent
aminopropyltriethoxysilane (APTrEOS). The structure and
properties of these hybrid materials were characterized via a
range of techniques including FTIR, TGA, DSC, SEM and
contact angle analysis. It was found that the compatibility
between organic and inorganic phases has been greatly
enhanced by the incorporation of APTrEOS. The thermal
stability and hydrophilic properties of hybrid materials have
also been significantly improved
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