8,384 research outputs found
A comparative study of characteristics of AZO based MISIM photodetectors with Al2O3 and SiO2 passivation layers
This paper reports aluminum (Al) doped zinc oxide (AZO) based metal-insulator-semiconductor-insulator-metal (MISIM) ultraviolet (U) photodetectors. Spray-coated Al2O3 and sputtered SiO2 have been used as passivation-layer for two different sets of MISIM devices, respectively. The spray-coated Al2O3 passivation-layer has been used first-time for AZO based MISIM U-photodetectors. A comparative study of current versus voltage characteristics of MISIM and MSM (without passivation-layer) devices have been done systematically. The MISIM devices with Al2O3 passivation-layer showed better performance than MSM and MISIM (with SiO2) U-photodetectors. These AZO based MISIM (with spray-coated Al2O3) U-photodetectors can be used for low-cost optoelectronic applications
Cost Effective Information Dispersal and Retrieval Framework for Cloud Storage
Cloud data storage applications widely demand security of data with minimum cost. Various cloud computing security threats supposed to be addressed in Cloud data service include Data Access Controllability, Data Confidentiality, and Data Integrity. In this paper, we propose a cost effective Information Dispersal and Retrieval framework for Cloud storage. Our proposed framework is different from existing approaches of replication. In our approach, multiple datacenters are considered as virtual independent disks for storing redundant data encoded with erasure codes and hence the proposed framework enables to retrieve user file even when failure of certain number of Cloud services occur . Besides security related benefits of our approach, the application provides user the cost-availability pattern of datacenters and allows cost effective storage on Cloud within user�s budget limit
Synthesis and characterization of Na03RhO206H2O - a semiconductor with a weak ferromagnetic component
We have prepared the oxyhydrate Na03RhO206H2O by extracting Na+ cations from
NaRhO2 and intercalating water molecules using an aqueous solution of Na2S2O8.
Synchrotron X-ray powder diffraction, thermogravimetric analysis (TGA), and
energy-dispersive x-ray analysis (EDX) reveal that a non-stoichiometric
Na03(H2O)06 network separates layers of edge-sharing RhO6 octahedra containing
Rh3+(4d6, S=0) and Rh4+ (4d5, S=1/2). The resistivities of NaRhO2 and
Na03RhO206H2O (T < 300) reveal insulating and semi-conducting behavior with
activation gaps of 134 meV and 7.8 meV, respectively. Both Na03RhO206H2O and
NaRhO2 show paramagnetism at room temperature, however, the sodium-deficient
sample exhibits simultaneously a weak but experimentally reproducible
ferromagnetic component. Both samples exhibit a temperature-independent Pauli
paramagnetism, for NaRhO2 at T > 50 K and for Na03RhO206H2O at T > 25 K. The
relative magnitudes of the temperature-independent magnetic susceptibilities,
that of the oxide sample being half that of the oxyhydrate, is consistent with
a higher density of thermally accessible electron states at the Fermi level in
the hydrated sample. At low temperatures the magnetic moments rise sharply,
providing evidence of localized and weakl -ordered electronic spins.Comment: 15 fages 5 figures Solid State Communications in prin
Impact of pulse oximetry screening to detect congenital heart defects: 5Â years' experience in a UK regional neonatal unit.
Pulse oximetry screening (POS) has been shown to be an effective, non-invasive investigation that can detect up to 50-70% of previously undiagnosed congenital heart defects (CHDs). The aims of this study were to assess the accuracy of POS in detection of CHDs and its impact on clinical practice. All eligible newborn infants born between 1 Jan 2015 and 31 Dec 2019 in a busy regional neonatal unit were included in this prospective observational study. A positive POS was classified as two separate measurements of oxygen saturation  2% between pre- and post-ductal circulations. Overall, 23,614 infants had documented POS results. One hundred eighty nine (0.8%) infants had a true positive result: 6 had critical CHDs, 9 serious or significant CHDs, and a further 156/189 (83%) infants had significant non-cardiac conditions. Forty-three infants who had a normal POS were later diagnosed with the following categories of CHDs post-hospital discharge: 1 critical, 15 serious, 20 significant and 7 non-significant CHDs. POS sensitivity for detection of critical CHD was 85.7%, whereas sensitivity was only 33% for detection of major CHDs (critical and serious) needing surgery during infancy; specificity was 99.3%.Conclusion: Pulse oximetry screening showed moderate to high sensitivity in detection of undiagnosed critical CHDs; however, it failed to detect two-third of major CHDs. Our study further emphasises the significance of adopting routine POS to detect critical CHDs in the clinical practice. However, it also highlights the need to develop new, innovative methods, such as perfusion index, to detect other major CHDs missed by current screening tools. What is Known: • Pulse oximetry screening is cost effective, acceptable, easy to perform and has moderate sensitivity and high specificity in detection of critical congenital heart defects. • Pulse oximetry screening has been implemented many countries including USA for detection of critical congenital heart defects, but it is not currently recommended by the UK National Screening Committee. What is New: • To our knowledge, this is the first study describing postnatal detection and presentation of all the infants with congenital heart defects over a period of 5 years, including those not detected on the pulse oximetry screening, on the clinical practice. • It emphasises that further research required to detect critical congenital heart defects and other major CHDs which can be missed on the screening tools currently employed in clinical practice
A Raspberry Pi-based Traumatic Brain Injury Detection System for Single-Channel Electroencephalogram
Traumatic Brain Injury (TBI) is a common cause of death and disability.
However, existing tools for TBI diagnosis are either subjective or require
extensive clinical setup and expertise. The increasing affordability and
reduction in size of relatively high-performance computing systems combined
with promising results from TBI related machine learning research make it
possible to create compact and portable systems for early detection of TBI.
This work describes a Raspberry Pi based portable, real-time data acquisition,
and automated processing system that uses machine learning to efficiently
identify TBI and automatically score sleep stages from a single-channel
Electroen-cephalogram (EEG) signal. We discuss the design, implementation, and
verification of the system that can digitize EEG signal using an Analog to
Digital Converter (ADC) and perform real-time signal classification to detect
the presence of mild TBI (mTBI). We utilize Convolutional Neural Networks (CNN)
and XGBoost based predictive models to evaluate the performance and demonstrate
the versatility of the system to operate with multiple types of predictive
models. We achieve a peak classification accuracy of more than 90% with a
classification time of less than 1 s across 16 s - 64 s epochs for TBI vs
control conditions. This work can enable development of systems suitable for
field use without requiring specialized medical equipment for early TBI
detection applications and TBI research. Further, this work opens avenues to
implement connected, real-time TBI related health and wellness monitoring
systems.Comment: 12 pages, 6 figure
[2-Hydroxy-N′-(4-oxo-4-phenylÂbutan-2-ylÂidene)benzohydrazidato(2−)]pyridineÂcopper(II)
The mononuclear title complex, [Cu(C17H14N2O3)(C5H5N)], was synthesized by the reaction of CuCl2·2H2O with N-(4-oxo-4-phenylÂbutan-2-ylÂidene)benzohydrazide (H2
L). The central CuII atom exhibits a distorted square-planar coordination geometry, defined by two O atoms, one N atom from the ligand and one pyridine N atom with Cu—N distances of 1.874 (4) and 1.963 (4) Å, while the Cu—O distances are 1.857 (3) and 1.890 (3) Å. An intraÂmolecular O—H⋯N interÂaction occurs
Electronic correlations in the iron pnictides
In correlated metals derived from Mott insulators, the motion of an electron
is impeded by Coulomb repulsion due to other electrons. This phenomenon causes
a substantial reduction in the electron's kinetic energy leading to remarkable
experimental manifestations in optical spectroscopy. The high-Tc
superconducting cuprates are perhaps the most studied examples of such
correlated metals. The occurrence of high-Tc superconductivity in the iron
pnictides puts a spotlight on the relevance of correlation effects in these
materials. Here we present an infrared and optical study on single crystals of
the iron pnictide superconductor LaFePO. We find clear evidence of electronic
correlations in metallic LaFePO with the kinetic energy of the electrons
reduced to half of that predicted by band theory of nearly free electrons.
Hallmarks of strong electronic many-body effects reported here are important
because the iron pnictides expose a new pathway towards a correlated electron
state that does not explicitly involve the Mott transition.Comment: 10 page
Spin excitations and the Fermi surface of superconducting FeS
High-temperature superconductivity occurs near antiferromagnetic
instabilities and nematic state. Debate remains on the origin of nematic order
in FeSe and its relation with superconductivity. Here, we use transport,
neutron scatter- ing and Fermi surface measurements to demonstrate that
hydro-thermo grown superconducting FeS, an isostructure of FeSe, is a
tetragonal paramagnet without nematic order and with a quasiparticle mass
significantly reduced from that of FeSe. Only stripe-type spin excitation is
observed up to 100 meV. No direct coupling between spin excitation and
superconductivity in FeS is found, suggesting that FeS is less correlated and
the nematic order in FeSe is due to competing checkerboard and stripe spin
fluctuations.Comment: 11 pages, 4 page
Structural phase control of (LaNdSr)CuO thin films by epitaxial growth technique
Epitaxial growth of (LaNdSr)CuO thin films was
studied by pulsed-laser deposition technique on three different substrates,
SrTiO (100), LaSrAlO (001), and YAlO (001). The
(Nd,Sr,Ce)CuO-type structure appears at the initial growth stage on
SrTiO (100) when the film is deposited under the growth conditions
optimized for (La,Sr)CuO. This (Nd,Sr,Ce)CuO-type structure can
be eliminated by increasing the substrate temperature and the laser repetition
frequency. Films on LaSrAlO (001) maintain a LaCuO-type structure
as bulk samples, but those on YAlO (001) show phase separation into
LaCuO- and NdCuO-type structures. Such complicated results are
explained in terms of the competition between lattice misfit and thermodynamic
conditions. Interestingly the films with LaCuO-type structure prepared
on SrTiO and LaSrAlO show different surface structures and transport
properties. The results indicate the possibility of controlling charge stripes
of (LaNdSr)CuO as was demonstrated in
(La,Ba)CuO thin films by Sato et al. (Phys. Rev. B {\bf 62}, R799
(2000)).Comment: 5 pages, 6 EPS figure, accepted for publication in Phys. Rev.
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