5,961 research outputs found
Design and fabrication of a microfluidic device for synthesis of chitosan nanoparticles
Cataloged from PDF version of article.Chitosan nanoparticles have a biodegradable, biocompatible, nontoxic structure, and are commonly used for drug delivery systems. In this study, design, modeling, and fabrication methodology of a microfluidic device for the synthesis of chitosan nanoparticles is presented. In the modeling, 2D flow and concentration field is computed using COMSOL Multiphysics® simulation environment to predict the performance of the device. The microfluidic chip is fabricated out of PDMS. The fabrication of the mold for the microfluidic device is performed using high-precision micromachining. Some preliminary proof-of-concept experiments were performed. It was observed that compared to conventional batch-type methods, the proposed microfluidic device can perform the synthesis much faster and in a much automated and convenient manner. Copyright © 2013 by ASME
EEG Classification based on Image Configuration in Social Anxiety Disorder
The problem of detecting the presence of Social Anxiety Disorder (SAD) using
Electroencephalography (EEG) for classification has seen limited study and is
addressed with a new approach that seeks to exploit the knowledge of EEG sensor
spatial configuration. Two classification models, one which ignores the
configuration (model 1) and one that exploits it with different interpolation
methods (model 2), are studied. Performance of these two models is examined for
analyzing 34 EEG data channels each consisting of five frequency bands and
further decomposed with a filter bank. The data are collected from 64 subjects
consisting of healthy controls and patients with SAD. Validity of our
hypothesis that model 2 will significantly outperform model 1 is borne out in
the results, with accuracy -- higher for model 2 for each machine
learning algorithm we investigated. Convolutional Neural Networks (CNN) were
found to provide much better performance than SVM and kNNs
Visual-only recognition of normal, whispered and silent speech
Silent speech interfaces have been recently proposed as a way to enable communication when the acoustic signal is not available. This introduces the need to build visual speech recognition systems for silent and whispered speech. However, almost all the recently proposed systems have been trained on vocalised data only. This is in contrast with evidence in the literature which suggests that lip movements change depending on the speech mode. In this work, we introduce a new audiovisual database which is publicly available and contains normal, whispered and silent speech. To the best of our knowledge, this is the first study which investigates the differences between the three speech modes using the visual modality only. We show that an absolute decrease in classification rate of up to 3.7% is observed when training and testing on normal and whispered, respectively, and vice versa. An even higher decrease of up to 8.5% is reported when the models are tested on silent speech. This reveals that there are indeed visual differences between the 3 speech modes and the common assumption that vocalized training data can be used directly to train a silent speech recognition system may not be true
A novel thiazolidine compound induces caspase-9 dependent apoptosis in cancer cells
Cataloged from PDF version of article.The forward chemogenomics strategy allowed us to identify a potent cytotoxic thiazolidine compound as an apoptosis-inducing agent. Chemical structures were designed around a thiazolidine ring, a structure already noted for its anticancer properties. Initially, we evaluated these novel compounds on liver, breast, colon and endometrial cancer cell lines. The compound 3 (ALC67) showed the strongest cytotoxic activity (IC50 ∼5 μM). Cell cycle analysis with ALC67 on liver cells revealed SubG1/G1 arrest bearing apoptosis. Furthermore we demonstrated that cytotoxicity of this compound was due to the activation of caspase-9 involved apoptotic pathway, which is death receptor independent. © 2012 Elsevier Ltd. All rights reserve
Search for axions in streaming dark matter
A new search strategy for the detection of the elusive dark matter (DM) axion
is proposed. The idea is based on streaming DM axions, whose flux might get
temporally enormously enhanced due to gravitational lensing. This can happen if
the Sun or some planet (including the Moon) is found along the direction of a
DM stream propagating towards the Earth location. The experimental requirements
to the axion haloscope are a wide-band performance combined with a fast axion
rest mass scanning mode, which are feasible. Once both conditions have been
implemented in a haloscope, the axion search can continue parasitically almost
as before. Interestingly, some new DM axion detectors are operating wide-band
by default. In order not to miss the actually unpredictable timing of a
potential short duration signal, a network of co-ordinated axion antennae is
required, preferentially distributed world-wide. The reasoning presented here
for the axions applies to some degree also to any other DM candidates like the
WIMPs.Comment: 5 page
Dual functionality of conjugated polymer nanoparticles as an anticancer drug carrier and a fluorescent probe for cell imaging
Cataloged from PDF version of article.Multifunctional nanoparticles based on a green emitting, hydrophobic conjugated polymer, poly[(9,9-bis{propeny}fluorenyl-2,7-diyl)-co-(1,4- benzo-{2,1,3}-thiodiazole)] (PPFBT), that acts both as a fluorescent reporter and a matrix to accommodate an anti-cancer compound, camptothecin (CPT), were prepared, characterized and their potential as a fluorescent probe for cell imaging and as a drug delivery vehicle were evaluated via in vitro cell assays. The cell viability of human hepatocellular carcinoma cell line (Huh7) was investigated in the absence and presence of CPT with sulforhodamine B (SRB) and real-time cell electronic sensing (RT-CES) cytotoxicity assays
Test beam studies of the TRD prototype filled with different gas mixtures based on Xe, Kr, and Ar
Towards the end of LHC Run1, gas leaks were observed in some parts of the
Transition Radiation Tracker (TRT) of ATLAS. Due to these leaks, primary Xenon
based gas mixture was replaced with Argon based mixture in various parts.
Test-beam studies with a dedicated Transition Radiation Detector (TRD)
prototype were carried out in 2015 in order to understand transition radiation
performance with mixtures based on Argon and Krypton. We present and discuss
the results of these test-beam studies with different active gas compositions.Comment: 5 pages,12 figures, The 2nd International Conference on Particle
Physics and Astrophysics (ICPPA-2016); Acknowledgments section correcte
Editorial: In Memoriam: Anastasios (Tas) N. Venetsanopoulos
[No abstract available
Longitudinal Doppler references for monochorionic twins and comparison with singletons
OBJECTIVES:
To construct monochorionic (MC) twin-specific longitudinal Doppler references for umbilical artery pulsatility index (UA-PI), middle cerebral artery (MCA) PI and peak systolic velocity (PSV) and ductus venosus (DV) PI derived from a strictly selected cohort of uncomplicated MC twins. The secondary aim of the study was to compare our findings with singleton reference charts.
METHODS:
A retrospective evaluation was made of all consecutive uncomplicated MC twin pregnancies referred to our Unit from 2010 to 2018. Fortnightly serial examinations were performed of UA-PI, MCA-PI, MCA-PSV and DV-PI, according with the clinical protocol, from 20 to 37 weeks of gestation. We included cases with at least four ultrasound examinations, delivery at our hospital and complete neonatal follow up. A two-step method was used to trace the estimated centile curves: estimation of the median was performed with appropriate fractional polynomials by a multilevel model and estimation of the external centiles through the residuals (quantile regression). The comparison with singletons was made by plotting the references derived from the present study on the referred charts commonly used for singletons.
RESULTS:
The study group comprised 150 uncomplicated MC twin pairs. Estimated centiles (3rd, 5th, 10th, 50th, 90th, 95th, 97th) of UA-PI, MCA-PI, MCA-PSV and DV-PI in function of the gestational age are presented. The comparison with singletons showed substantial differences, with higher UA-PI and lower MCA-PI and PSV median values in MC twins. Median DV PI values were similar to the values for singletons, while the upper centiles were higher in MC twins.
CONCLUSIONS:
This study sets out MC twin-specific longitudinal references for UA-PI, MCA-PI, MCA-PSV and DV-PI derived from the largest series of uncomplicated MC twin pregnancies presently available. The comparison with singleton reference values underscores the deviation from physiology that is intrinsic to these unique pregnancies and supports the need for MC twin-specific charts
Some results of test beam studies of Transition Radiation Detector prototypes at CERN
Operating conditions and challenging demands of present and future
accelerator experiments result in new requirements on detector systems. There
are many ongoing activities aimed to develop new technologies and to improve
the properties of detectors based on existing technologies. Our work is
dedicated to development of Transition Radiation Detectors (TRD) suitable for
different applications. In this paper results obtained in beam tests at SPS
accelerator at CERN with the TRD prototype based on straw technology are
presented. TRD performance was studied as a function of thickness of the
transition radiation radiator and working gas mixture pressure
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