1,075 research outputs found
Comparison of embedded and added motor imagery training in patients after stroke: Results of a randomised controlled pilot trial
Copyright @ 2012 Schuster et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Motor imagery (MI) when combined with physiotherapy can offer functional benefits after stroke. Two MI integration strategies exist: added and embedded MI. Both approaches were compared when learning a complex motor task (MT): ‘Going down, laying on the floor, and getting up again’. Methods: Outpatients after first stroke participated in a single-blinded, randomised controlled trial with MI embedded into physiotherapy (EG1), MI added to physiotherapy (EG2), and a control group (CG). All groups participated in six physiotherapy sessions. Primary study outcome was time (sec) to perform the motor task at pre and post-intervention. Secondary outcomes: level of help needed, stages of MT-completion, independence, balance, fear of falling (FOF), MI ability. Data were collected four times: twice during one week baseline phase (BL, T0), following the two week intervention (T1), after a two week follow-up (FU). Analysis of variance was performed. Results: Thirty nine outpatients were included (12 females, age: 63.4 ± 10 years; time since stroke: 3.5 ± 2 years; 29 with an ischemic event). All were able to complete the motor task using the standardised 7-step procedure and reduced FOF at T0, T1, and FU. Times to perform the MT at baseline were 44.2 ± 22s, 64.6 ± 50s, and 118.3 ± 93s for EG1 (N = 13), EG2 (N = 12), and CG (N = 14). All groups showed significant improvement in time to complete the MT (p < 0.001) and degree of help needed to perform the task: minimal assistance to supervision (CG) and independent performance (EG1+2). No between group differences were found. Only EG1 demonstrated changes in MI ability over time with the visual indicator increasing from T0 to T1 and decreasing from T1 to FU. The kinaesthetic indicator increased from T1 to FU. Patients indicated to value the MI training and continued using MI for other difficult-to-perform tasks. Conclusions: Embedded or added MI training combined with physiotherapy seem to be feasible and benefi-cial to learn the MT with emphasis on getting up independently. Based on their baseline level CG had the highest potential to improve outcomes. A patient study with 35 patients per group could give a conclusive answer of a superior MI integration strategy.The research project was partially funded by the Gottfried und Julia Bangerter-Rhyner Foundation
A transfer-learning approach to feature extraction from cancer transcriptomes with deep autoencoders
Publicado en Lecture Notes in Computer Science.The diagnosis and prognosis of cancer are among the more
challenging tasks that oncology medicine deals with. With the main aim
of fitting the more appropriate treatments, current personalized medicine
focuses on using data from heterogeneous sources to estimate the evolu-
tion of a given disease for the particular case of a certain patient. In recent
years, next-generation sequencing data have boosted cancer prediction by
supplying gene-expression information that has allowed diverse machine
learning algorithms to supply valuable solutions to the problem of cancer
subtype classification, which has surely contributed to better estimation
of patient’s response to diverse treatments. However, the efficacy of these
models is seriously affected by the existing imbalance between the high
dimensionality of the gene expression feature sets and the number of sam-
ples available for a particular cancer type. To counteract what is known
as the curse of dimensionality, feature selection and extraction methods
have been traditionally applied to reduce the number of input variables
present in gene expression datasets. Although these techniques work by
scaling down the input feature space, the prediction performance of tradi-
tional machine learning pipelines using these feature reduction strategies
remains moderate. In this work, we propose the use of the Pan-Cancer
dataset to pre-train deep autoencoder architectures on a subset com-
posed of thousands of gene expression samples of very diverse tumor
types. The resulting architectures are subsequently fine-tuned on a col-
lection of specific breast cancer samples. This transfer-learning approach
aims at combining supervised and unsupervised deep learning models
with traditional machine learning classification algorithms to tackle the
problem of breast tumor intrinsic-subtype classification.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Active diffusion and microtubule-based transport oppose myosin forces to position organelles in cells.
Even distribution of peroxisomes (POs) and lipid droplets (LDs) is critical to their role in lipid and reactive oxygen species homeostasis. How even distribution is achieved remains elusive, but diffusive motion and directed motility may play a role. Here we show that in the fungus Ustilago maydis ∼95% of POs and LDs undergo diffusive motions. These movements require ATP and involve bidirectional early endosome motility, indicating that microtubule-associated membrane trafficking enhances diffusion of organelles. When early endosome transport is abolished, POs and LDs drift slowly towards the growing cell end. This pole-ward drift is facilitated by anterograde delivery of secretory cargo to the cell tip by myosin-5. Modelling reveals that microtubule-based directed transport and active diffusion support distribution, mobility and mixing of POs. In mammalian COS-7 cells, microtubules and F-actin also counteract each other to distribute POs. This highlights the importance of opposing cytoskeletal forces in organelle positioning in eukaryotes.We thank Dr G. Dagdas, Dr S. Kilaru, Mr M. Schlick and Mrs T. Schrader for technical
support. We thank Professor N.J. Talbot for helpful comments on the manuscript.
This work was supported by the Biotechnology & Biological Sciences Research Council
(BB/J009903/1 to G.S.). S.C.G. was supported by a fellowship from the Portuguese
Foundation for Science and Technology (FCT) (SFRH/BD/73532/2010). J.M. is
supported by a Wellcome Trust Institutional Strategic Support Award (WT097835MF)
Erythropoietin/erythropoietin-receptor system is involved in angiogenesis in human hepatocellular carcinoma
Ribatti D, Marzullo A, Gentile A, Longo V, Nico B, Vacca A & Dammacco F (2007) Histopathology 50, 591–596 Erythropoietin/erythropoietin-receptor system is involved in angiogenesis in human hepatocellular carcinom
Cavity cooling of a single atom
All conventional methods to laser-cool atoms rely on repeated cycles of
optical pumping and spontaneous emission of a photon by the atom. Spontaneous
emission in a random direction is the dissipative mechanism required to remove
entropy from the atom. However, alternative cooling methods have been proposed
for a single atom strongly coupled to a high-finesse cavity; the role of
spontaneous emission is replaced by the escape of a photon from the cavity.
Application of such cooling schemes would improve the performance of atom
cavity systems for quantum information processing. Furthermore, as cavity
cooling does not rely on spontaneous emission, it can be applied to systems
that cannot be laser-cooled by conventional methods; these include molecules
(which do not have a closed transition) and collective excitations of Bose
condensates, which are destroyed by randomly directed recoil kicks. Here we
demonstrate cavity cooling of single rubidium atoms stored in an intracavity
dipole trap. The cooling mechanism results in extended storage times and
improved localization of atoms. We estimate that the observed cooling rate is
at least five times larger than that produced by free-space cooling methods,
for comparable excitation of the atom
Erythropoietin/erythropoietin receptor system is involved in angiogenesis in human neuroblastoma
Ribatti D, Poliani P L, Longo V, Mangieri D, Nico B & Vacca A (2007) Histopathology50, 636–641 Erythropoietin/erythropoietin receptor system is involved in angiogenesis in human neuroblastom
Note on New KLT relations
In this short note, we present two results about KLT relations discussed in
recent several papers. Our first result is the re-derivation of Mason-Skinner
MHV amplitude by applying the S_{n-3} permutation symmetric KLT relations
directly to MHV amplitude. Our second result is the equivalence proof of the
newly discovered S_{n-2} permutation symmetric KLT relations and the well-known
S_{n-3} permutation symmetric KLT relations. Although both formulas have been
shown to be correct by BCFW recursion relations, our result is the first direct
check using the regularized definition of the new formula.Comment: 15 Pages; v2: minor correction
Comparison of embedded and added motor imagery training in patients after stroke: Study protocol of a randomised controlled pilot trial using a mixed methods approach
Copyright @ 2009 Schuster et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Two different approaches have been adopted when applying motor imagery (MI) to stroke patients. MI can be conducted either added to conventional physiotherapy or integrated within therapy sessions. The proposed study aims to compare the efficacy of embedded MI to an added MI intervention. Evidence from pilot studies reported in the literature suggests that both approaches can improve performance of a complex motor skill involving whole body movements, however, it remains to be demonstrated, which is the more effective one.Methods/Design: A single blinded, randomised controlled trial (RCT) with a pre-post intervention design will be carried out. The study design includes two experimental groups and a control group (CG). Both experimental groups (EG1, EG2) will receive physical practice of a clinical relevant motor task ('Going down, laying on the floor, and getting up again') over a two week intervention period: EG1 with embedded MI training, EG2 with MI training added after physiotherapy. The CG will receive standard physiotherapy intervention and an additional control intervention not related to MI.The primary study outcome is the time difference to perform the task from pre to post-intervention. Secondary outcomes include level of help needed, stages of motor task completion, degree of motor impairment, balance ability, fear of falling measure, motivation score, and motor imagery ability score. Four data collection points are proposed: twice during baseline phase, once following the intervention period, and once after a two week follow up. A nested qualitative part should add an important insight into patients' experience and attitudes towards MI. Semi-structured interviews of six to ten patients, who participate in the RCT, will be conducted to investigate patients' previous experience with MI and their expectations towards the MI intervention in the study. Patients will be interviewed prior and after the intervention period.Discussion: Results will determine whether embedded MI is superior to added MI. Findings of the semi-structured interviews will help to integrate patient's expectations of MI interventions in the design of research studies to improve practical applicability using MI as an adjunct therapy technique
Characterization of growth and metabolism of the haloalkaliphile Natronomonas pharaonis
Natronomonas pharaonis is an archaeon adapted to two extreme conditions: high salt concentration and alkaline pH. It has become one of the model organisms for the study of extremophilic life. Here, we present a genome-scale, manually curated metabolic reconstruction for the microorganism. The reconstruction itself represents a knowledge base of the haloalkaliphile's metabolism and, as such, would greatly assist further investigations on archaeal pathways. In addition, we experimentally determined several parameters relevant to growth, including a characterization of the biomass composition and a quantification of carbon and oxygen consumption. Using the metabolic reconstruction and the experimental data, we formulated a constraints-based model which we used to analyze the behavior of the archaeon when grown on a single carbon source. Results of the analysis include the finding that Natronomonas pharaonis, when grown aerobically on acetate, uses a carbon to oxygen consumption ratio that is theoretically near-optimal with respect to growth and energy production. This supports the hypothesis that, under simple conditions, the microorganism optimizes its metabolism with respect to the two objectives. We also found that the archaeon has a very low carbon efficiency of only about 35%. This inefficiency is probably due to a very low P/O ratio as well as to the other difficulties posed by its extreme environment
Monotonicity of Fitness Landscapes and Mutation Rate Control
A common view in evolutionary biology is that mutation rates are minimised.
However, studies in combinatorial optimisation and search have shown a clear
advantage of using variable mutation rates as a control parameter to optimise
the performance of evolutionary algorithms. Much biological theory in this area
is based on Ronald Fisher's work, who used Euclidean geometry to study the
relation between mutation size and expected fitness of the offspring in
infinite phenotypic spaces. Here we reconsider this theory based on the
alternative geometry of discrete and finite spaces of DNA sequences. First, we
consider the geometric case of fitness being isomorphic to distance from an
optimum, and show how problems of optimal mutation rate control can be solved
exactly or approximately depending on additional constraints of the problem.
Then we consider the general case of fitness communicating only partial
information about the distance. We define weak monotonicity of fitness
landscapes and prove that this property holds in all landscapes that are
continuous and open at the optimum. This theoretical result motivates our
hypothesis that optimal mutation rate functions in such landscapes will
increase when fitness decreases in some neighbourhood of an optimum, resembling
the control functions derived in the geometric case. We test this hypothesis
experimentally by analysing approximately optimal mutation rate control
functions in 115 complete landscapes of binding scores between DNA sequences
and transcription factors. Our findings support the hypothesis and find that
the increase of mutation rate is more rapid in landscapes that are less
monotonic (more rugged). We discuss the relevance of these findings to living
organisms
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