2,071 research outputs found
Characterization of a Plain Broadband Textile PIFA
Bandwidth characteristic of a wearable antenna is one of the major factors in determining its usability on the human body. In this work, a planar inverted-F antenna (PIFA) structure is proposed to achieve a large bandwidth to avoid serious antenna reflection coefficient detuning when placed in proximity of the body. The proposed structure is designed based on a simple structure, in order to provide practicality in application and maintain fabrication simplicity. Two different types of conductive textiles, namely Pure Copper Polyester Taffeta Fabric (PCPTF) and ShieldIt, are used in order to proof its concept, in comparison with a metallic antenna made from copper foil. The design is spaced and fabricated using a 6 mm thick fleece fabric. To cater for potential fabrication and material measurement inaccuracies, both antennas' performance are also investigated and analyzed with varying physical and material parameters. From this investigation, it is found that the proposed structure's extended bandwidth enabled the antenna to function with satisfactory on-body reflection coefficients, despite unavoidable gain and efficiency reduction
A feasibility study of perioperative vitamin D supplementation in patients undergoing colorectal cancer resection
BackgroundVitamin D supplementation improves colorectal cancer (CRC) survival outcomes in randomized trials. The aim of this study was to test the feasibility, safety and efficacy of vitamin D supplementation in the pre- and perioperative period in patients undergoing CRC surgery.MethodsPatients were given 3200IU oral cholecalciferol (D3) per day perioperatively. Serial serum 25-hydroxyvitamin (25OHD) was measured by liquid chromatography tandem mass spectrometry and compared to untreated CRC controls. 25OHD and C-reactive protein (CRP) levels were compared using adjusted generalized linear mixed-effects models.ResultsA total of 122 patients underwent serial perioperative sampling, including 41 patients given high-dose perioperative supplementation. Supplementation was well-tolerated with no adverse or serious adverse events related to supplementation reported. Pre-operative supplementation increased 25OHD levels on the day of surgery (103.9 vs. 42.5 nmol/l, P = 8.2E–12). Supplementation increased 25OHD levels at all post-operative timepoints (P < 0.001) and attenuated the post-operative drop in 25OHD (46 vs. 24% drop, P = 3.0E–4). Rate of vitamin D peri-operative insufficiency was significantly less in those on supplementation (e.g., day 3–5, 14 vs. 84%, P = 1.41E–08), with multivariate modeling across all timepoints indicating a ∼59 nmol/l higher 25OHD compared to control patients (P = 3.7E–21). Post-operative CRP was lower in patients taking supplementation (e.g., day 3–5 timepoint; 129 vs. 81 mg/l, P = 0.04).ConclusionHigh dose pre-operative vitamin D supplementation is associated with higher perioperative 25OHD levels, lower rates of vitamin D insufficiency and reduced early post-operative CRP. Alongside published evidence for a beneficial effect of vitamin D on CRC survival outcomes, these novel findings provide strong rationale for early initiation of vitamin D supplementation after a diagnosis of CRC
Biologically Inspired Monocular Vision Based Navigation and Mapping in GPS-Denied Environments
This paper presents an in-depth theoretical study of bio-vision inspired feature extraction and depth perception method integrated with vision-based simultaneous localization and mapping (SLAM). We incorporate the key functions of developed visual cortex in several advanced species, including humans, for depth perception and pattern recognition. Our navigation strategy assumes GPS-denied manmade environment consisting of orthogonal walls, corridors and doors. By exploiting the architectural features of the indoors, we introduce a method for gathering useful landmarks from a monocular camera for SLAM
use, with absolute range information without using active ranging sensors. Experimental results show that the system is only limited by the capabilities of the camera and the
availability of good corners. The proposed methods are experimentally validated by our self-contained MAV inside a conventional building
Evidence for Surface Andreev Bound states in Cuprate Superconductors from Penetration Depth Measurements
Tunneling and theoretical studies have suggested that Andreev bound states
form at certain surfaces of unconventional superconductors. Through studies of
the temperature and field dependence of the in-plane magnetic penetration depth
lambda_ab at low temperature, we have found strong evidence for the presence of
these states in clean single crystal YBCO and BSCCO. Crystals cut to expose a
[110] interface show a strong upturn in lambda_ab at around 7K, when the field
is oriented so that the supercurrents flow around this surface. In YBCO this
upturn is completely suppressed by a field of ~0.1 T.Comment: 4 pages 2 column revtex + 4 postscript figures. Submitted to PR
NRF2-driven miR-125B1 and miR-29B1 transcriptional regulation controls a novel anti-apoptotic miRNA regulatory network for AML survival
Transcription factor NRF2 is an important regulator of oxidative stress. It is involved in cancer progression, and has abnormal constitutive expression in acute myeloid leukaemia (AML). Posttranscriptional regulation by microRNAs (miRNAs) can affect the malignant phenotype of AML cells. In this study, we identified and characterised NRF2-regulated miRNAs in AML. An miRNA array identified miRNA expression level changes in response to NRF2 knockdown in AML cells. Further analysis of miRNAs concomitantly regulated by knockdown of the NRF2 inhibitor KEAP1 revealed the major candidate NRF2-mediated miRNAs in AML. We identified miR-125B to be upregulated and miR-29B to be downregulated by NRF2 in AML. Subsequent bioinformatic analysis identified putative NRF2 binding sites upstream of the miR-125B1 coding region and downstream of the mir-29B1 coding region. Chromatin immunoprecipitation analyses showed that NRF2 binds to these antioxidant response elements (AREs) located in the 5′ untranslated regions of miR-125B and miR-29B. Finally, primary AML samples transfected with anti-miR-125B antagomiR or miR-29B mimic showed increased cell death responsiveness either alone or co-treated with standard AML chemotherapy. In summary, we find that NRF2 regulation of miR-125B and miR-29B acts to promote leukaemic cell survival, and their manipulation enhances AML responsiveness towards cytotoxic chemotherapeutics
Oral vitamin D supplementation induces transcriptomic changes in rectal mucosa that are linked to anti-tumour effects
Abstract Background The risk for several common cancers is influenced by the transcriptomic landscape of the respective tissue-of-origin. Vitamin D influences in vitro gene expression and cancer cell growth. We sought to determine whether oral vitamin D induces beneficial gene expression effects in human rectal epithelium and identify biomarkers of response. Methods Blood and rectal mucosa was sampled from 191 human subjects and mucosa gene expression (HT12) correlated with plasma vitamin D (25-OHD) to identify differentially expressed genes. Fifty subjects were then administered 3200IU/day oral vitamin D3 and matched blood/mucosa resampled after 12 weeks. Transcriptomic changes (HT12/RNAseq) after supplementation were tested against the prioritised genes for gene-set and GO-process enrichment. To identify blood biomarkers of mucosal response, we derived receiver-operator curves and C-statistic (AUC) and tested biomarker reproducibility in an independent Supplementation Trial (BEST-D). Results Six hundred twenty-nine genes were associated with 25-OHD level (P < 0.01), highlighting 453 GO-term processes (FDR<0.05). In the whole intervention cohort, vitamin D supplementation enriched the prioritised mucosal gene-set (upregulated gene-set P < 1.0E−07; downregulated gene-set P < 2.6E−05) and corresponding GO terms (P = 2.90E−02), highlighting gene expression patterns consistent with anti-tumour effects. However, only 9 individual participants (18%) showed a significant response (NM gene-set enrichment P < 0.001) to supplementation. Expression changes in HIPK2 and PPP1CC expression served as blood biomarkers of mucosal transcriptomic response (AUC=0.84 [95%CI 0.66–1.00]) and replicated in BEST-D trial subjects (HIPK2 AUC=0.83 [95%CI 0.77–0.89]; PPP1CC AUC=0.91 [95%CI 0.86–0.95]). Conclusions Higher plasma 25-OHD correlates with rectal mucosa gene expression patterns consistent with anti-tumour effects, and this beneficial signature is induced by short-term vitamin D supplementation. Heterogenous gene expression responses to vitamin D may limit the ability of randomised trials to identify beneficial effects of supplementation on CRC risk. However, in the current study blood expression changes in HIPK2 and PPP1CC identify those participants with significant anti-tumour transcriptomic responses to supplementation in the rectum. These data provide compelling rationale for a trial of vitamin D and CRC prevention using easily assayed blood gene expression signatures as intermediate biomarkers of response
Possible new vortex matter phases in BSCCO
The vortex matter phase diagram of BSCCO crystals is analyzed by
investigating vortex penetration through the surface barrier in the presence of
a transport current. The strength of the effective surface barrier, its
nonlinearity, and asymmetry are used to identify a possible new ordered phase
above the first-order transition. This technique also allows sensitive
determination of the depinning temperature. The solid phase below the
first-order transition is apparently subdivided into two phases by a vertical
line extending from the multicritical point.Comment: 11 pages, 3 figures, accepted for publication in PR
Arsenolite: a quasi-hydrostatic solid pressure transmitting medium
This study reports the experimental characterization of the hydrostatic properties of arsenolite
(As4O6), a molecular solid which is one of the softest minerals in the absence of hydrogen
bonding. The high compressibility of arsenolite and its stability up to 15GPa have been
proved by x-ray diffraction measurements, and the progressive loss of hydrostaticity with
increasing pressure up to 20GPa has been monitored by ruby photoluminescence. Arsenolite
has been found to exhibit hydrostatic behavior up to 2.5GPa and a quasi-hydrostatic behavior
up to 10GPa at room temperature. This result opens the way to explore other molecular solids
as possible quasi-hydrostatic pressure-transmitting media. The validity of arsenolite as an
insulating, stable, non-penetrating and quasi-hydrostatic medium is explored by the study of
the x-ray diffraction of zeolite ITQ-29 at high pressure.This work has been performed with financial support from Spanish MINECO under projects MAT2013-46649-C4-2/3-P and MAT2015-71070-REDC. JAS acknowledges the 'Ramon y Cajal' fellowship program for financial support. We also thank D Calatayud, J J Garcia, T M Godoy, A Zapata, and A Cuenca for fruitful discussions. The authors thank ALBA light source for beam allocation at beamline MSPD. JLJ and FR acknowledge financial support through the SEV-2012-0267, Consolider Ingenio 2010-Multicat (CSD-2009-0050) and MAT2015-71842-P (MINECO/FEDER) projects.Sans-Tresserras, JÁ.; Manjón, FJ.; Popescu, C.; Muñoz, A.; Rodríguez-Hernández, P.; Jordá, JL.; Rey Garcia, F. (2016). Arsenolite: a quasi-hydrostatic solid pressure transmitting medium. Journal of Physics: Condensed Matter. 28(47):475403-1-475403-7. doi:10.1088/0953-8984/28/47/475403S475403-1475403-7284
Graphite and Hexagonal Boron-Nitride Possess the Same Interlayer Distance. Why?
Graphite and hexagonal boron nitride (h-BN) are two prominent members of the
family of layered materials possessing a hexagonal lattice. While graphite has
non-polar homo-nuclear C-C intra-layer bonds, h-BN presents highly polar B-N
bonds resulting in different optimal stacking modes of the two materials in
bulk form. Furthermore, the static polarizabilities of the constituent atoms
considerably differ from each other suggesting large differences in the
dispersive component of the interlayer bonding. Despite these major differences
both materials present practically identical interlayer distances. To
understand this finding, a comparative study of the nature of the interlayer
bonding in both materials is presented. A full lattice sum of the interactions
between the partially charged atomic centers in h-BN results in vanishingly
small monopolar electrostatic contributions to the interlayer binding energy.
Higher order electrostatic multipoles, exchange, and short-range correlation
contributions are found to be very similar in both materials and to almost
completely cancel out by the Pauli repulsions at physically relevant interlayer
distances resulting in a marginal effective contribution to the interlayer
binding. Further analysis of the dispersive energy term reveals that despite
the large differences in the individual atomic polarizabilities the
hetero-atomic B-N C6 coefficient is very similar to the homo-atomic C-C
coefficient in the hexagonal bulk form resulting in very similar dispersive
contribution to the interlayer binding. The overall binding energy curves of
both materials are thus very similar predicting practically the same interlayer
distance and very similar binding energies.Comment: 18 pages, 5 figures, 2 table
Identification and validation of clinical predictors for the risk of neurological involvement in children with hand, foot, and mouth disease in Sarawak
Background: Human enterovirus 71 (HEV71) can cause Hand, foot, and mouth disease (HFMD) with neurological
complications, which may rapidly progress to fulminant cardiorespiratory failure, and death. Early recognition of children
at risk is the key to reduce acute mortality and morbidity.
Methods: We examined data collected through a prospective clinical study of HFMD conducted between 2000 and 2006
that included 3 distinct outbreaks of HEV71 to identify risk factors associated with neurological involvement in children
with HFMD.
Results: Total duration of fever ≥ 3 days, peak temperature ≥ 38.5°C and history of lethargy were identified as
independent risk factors for neurological involvement (evident by CSF pleocytosis) in the analysis of 725 children
admitted during the first phase of the study. When they were validated in the second phase of the study, two or more
(≥ 2) risk factors were present in 162 (65%) of 250 children with CSF pleocytosis compared with 56 (30%) of 186 children
with no CSF pleocytosis (OR 4.27, 95% CI2.79–6.56, p < 0.0001). The usefulness of the three risk factors in identifying
children with CSF pleocytosis on hospital admission during the second phase of the study was also tested. Peak
temperature ≥ 38.5°C and history of lethargy had the sensitivity, specificity, positive predictive value (PPV) and negative
predictive value (NPV) of 28%(48/174), 89%(125/140), 76%(48/63) and 50%(125/251), respectively in predicting CSF
pleocytosis in children that were seen within the first 2 days of febrile illness. For those presented on the 3rd or later day
of febrile illness, the sensitivity, specificity, PPV and NPV of ≥ 2 risk factors predictive of CSF pleocytosis were 75%(57/
76), 59%(27/46), 75%(57/76) and 59%(27/46), respectively.
Conclusion: Three readily elicited clinical risk factors were identified to help detect children at risk of neurological
involvement. These risk factors may serve as a guide to clinicians to decide the need for hospitalization and further
investigation, including cerebrospinal fluid examination, and close monitoring for disease progression in children with
HFMD
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