11 research outputs found
Study of nano-mechanical performance of pretreated natural fiber in ldpe composite for packaging applications
No full textIn this work, the effects of chemical pretreatment and different fiber loadings on mechanical properties of the composites at the sub-micron scale were studied through nanoindentation. The composites were prepared by incorporating choline chloride (ChCl) pretreated rice husk waste (RHW) in low-density polyethylene (LDPE) using melt processing, followed by a thermal press technique. Nanoindentation experiments with quasi continuous stiffness mode (QCSM) were performed on the surface of produced composites with varying content of pretreated RHW (i.e., 10, 15, and 20 wt.%). Elastic modulus, hardness, and creep properties of fabricated composites were measured as a function of contact depth. The results confirmed the appreciable changes in hardness, elastic modulus, and creep rate of the composites. Compliance curves indicated that the composite having 20 wt.% of pretreated RHW loading was harder compared to that of the pure LDPE and other composite samples. The values of elastic modulus and hardness of the composite containing 20 wt.% pretreated RHW were increased by 4.1% and 24% as compared to that of the pure LDPE, respectively. The creep rate of 42.65 nm/s and change in depth of 650.42 nm were also noted for the composite with RHW loading of 20 wt.%, which showed the substantial effect of holding time at an applied peak load of 100 mN. We believe that the developed composite could be a promising biodegradable packaging material due to its good tribo-mechanical performance.Rivers, Ports, Waterways and Dredging Engineerin
Effect of photochemical ageing on the ice nucleation properties of diesel and wood burning particles
No full textA measurement campaign (IMBALANCE) conducted in 2009 was aimed at characterizing the physical and chemical properties of freshly emitted and photochemically aged combustion particles emitted from a log wood burner and diesel vehicles: a EURO3 Opel Astra with a diesel oxidation catalyst (DOC) but no particle filter and a EURO2 Volkswagen Transporter TDI Syncro without emission aftertreatment. Ice nucleation experiments in the deposition and condensation freezing modes were conducted with the Portable Ice Nucleation Chamber (PINC) at three nominal temperatures,-30°C,-35°C and-40°C. Freshly emitted diesel particles showed ice formation only at-40°C in the deposition mode at 137% relative humidity with respect to ice (RHi) and 92% relative humidity with respect to water (RHw), and photochemical ageing did not play a role in modifying their ice nucleation behaviour. Only one diesel experiment where α-pinene was added for the ageing process, showed an ice nucleation enhancement at-35°C. Wood burning particles also act as ice nuclei (IN) at-40°C in the deposition mode at the same conditions as for diesel particles and photochemical ageing also did not alter the ice formation properties of the wood burning particles. Unlike diesel particles, wood burning particles form ice via condensation freezing at-35°C whereas no ice nucleation was observed at-30°C. Photochemical ageing did not affect the ice nucleation ability of the diesel and wood burning particles at the three different temperatures investigated but a broader range of temperatures below-40°C need to be investigated in order to draw an overall conclusion on the effect of photochemical ageing on deposition/condensation ice nucleation across the entire temperature range relevant to cold clouds. © 2013 Author(s)
A prospective pilot study of the effect of acupuncture on insulin sensitivity in women with polycystic ovary syndrome and insulin resistance
No full textObjective: To test the hypothesis that acupuncture improves insulin sensitivity in women with polycystic ovary syndrome (PCOS) and insulin resistance (IR). Design: Prospective pilot study. Setting: Guangzhou, China, 2014–2016. Participants: Eighty women with PCOS aged 18–40 years with body mass index (BMI) above 18.5 kg/m2 and with homeostatic model assessment for insulin resistance (HOMA-IR) index ⩾2.14. Interventions: Subjects received acupuncture with combined manual and low-frequency electrical stimulation of the needles three times per week for 6 months. Primary and secondary outcome measures: The primary outcome was the change in HOMA-IR after 6 months of acupuncture relative to baseline. Secondary outcomes included changes after 6 months of acupuncture and at 3 months of follow-up (both relative to baseline) in oral glucose tolerance test (OGTT) parameters (glucose and insulin levels), anthropometric measurements, and circulating metabolic and endocrine variables. Results: HOMA-IR and fasting plasma glucose and insulin levels were significantly decreased after 6 months of acupuncture, and both HOMA-IR and fasting insulin remained significantly decreased at 3 months of follow-up. In a subgroup analysis of normal-weight and overweight/obese women, HOMA-IR was reduced after 6 months of acupuncture in both subgroups, but there was no significant difference between the two groups. Conclusions: Acupuncture treatment in Chinese women with PCOS and IR was associated with an encouraging improvement in insulin sensitivity. Further randomized controlled studies are required to confirm the efficacy of acupuncture for this indication. © The Author(s) 2020.postprin
Anomalous origin of right coronary artery from the left coronary sinus: Incidence, characteristics, and a systematic approach for rapid diagnosis
No full textTwenty-three patients were found to have anomalous origin of right coronary artery from the left coronary sinus (LCS) from January 2000 to October 2003. The mean age was 58.6 ± 14.3 years with male predominance (56.5%). Cardiovascular risk factors were found in 18 (78.3%) patients while coronary artery disease was seen in 13 (56.5%) patients. Among the coronary artery disease patients, the left anterior descending artery was the most commonly involved, followed by the right coronary artery and the left circumflex artery. Right coronary artery dominance was seen in 19 (82.6%) patients. The anomalous right coronary artery originates within the left coronary sinus in 17 (73.9%) patients while from the left aortic wall above the sinus in 6 (26.1%) patients only. Congenital heart disease and acquired valvular heart disease were the most common associated conditions. The author will share his experience and suggest a four-step approach of early recognition and selection of the anomalous right coronary artery ostium. Using the suggested strategy, most of the anomalous right coronary artery could be opacified with a left amplatz 1 catheter. Aortogram was needed only in 47.8% of cases.link_to_subscribed_fulltex
Searching for dark matter signals from local dwarf spheroidal galaxies at low radio frequencies in the GLEAM survey
No full text© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society The search for emission from weakly interacting massive particle (WIMP) dark matter annihilation and decay has become a multipronged area of research not only targeting a diverse selection of astrophysical objects, but also taking advantage of the entire electromagnetic spectrum. The decay of WIMP particles into standard model particles has been suggested as a possible channel for synchrotron emission to be detected at low radio frequencies. Here, we present the stacking analysis of a sample of 33 dwarf spheroidal (dSph) galaxies with low-frequency (72-231 MHz) radio images from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. We produce radial surface brightness profiles of images centred upon each dSph galaxy with background radio sources masked. We remove 10 fields from the stacking due to contamination from either poorly subtracted, bright radio sources or strong background gradients across the field. The remaining 23 dSph galaxies are stacked in an attempt to obtain a statistical detection of any WIMP-induced synchrotron emission in these systems. We find that the stacked radial brightness profile does not exhibit a statistically significant detection above the 95 per cent confidence level of ∼1.5 mJy beam−1. This novel technique shows the potential of using low-frequency radio images to constrain fundamental properties of particle dark matter
A Markov decision analysis model to aid the vascular surgeon in the management of a patient with an asymptomatic infra-renal abdominal aortic aneurysm
No full textAbstract
Introduction
Despite increasing evidence regarding the safety and efficacy of endovascular (EVAR) and open abdominal aortic aneurysm repair, it is often unclear which technique is most appropriate for an individual patient. We have designed a decision analysis model that will predict survival, reintervention rates and other parameters for individual patients.
Methods
A Markov decision analysis model was developed in Microsoft Excel to simulate five management options; EVAR, open repair, best medical therapy or delayed EVAR or open repair at a threshold aneurysm diameter. Probabilities for the model were determined from systematic literature review. The user can assess the impact of adjusting patient-specific risk-factors including aneurysm size, threshold diameter for intervention, operative mortality, hazard ratios for general mortality, reintervention rate and aneurysm rupture rate.
Results
Patient and aneurysm specific variables are entered through a user-friendly data-input sheet and the model generates graphical and descriptive results regarding estimated survival and reintervention rates for the different management options. Individualised survival curves, both aneurysm-related and general mortality curves, cumulative reintervention rates and other key parameters are generated for each management option. The model has been validated against average data published from recent RCTs and examples have been generated based on real and hypothetical patient characteristics.
Conclusions
An easy-to-use computer model has been developed that will provide meaningful information relating to risks and benefits that could assist in shared decision making and obtaining informed consent from patients with aneurysms, and could help to guide policy decisions in respect to patient selection for EVAR
Measuring luteinising hormone pulsatility with a robotic aptamer-enabled electrochemical reader
No full textThis is the final version. Available from the publisher via the DOI in this record.Normal reproductive functioning is critically dependent on pulsatile secretion of luteinising hormone (LH). Assessment of LH pulsatility is important for the clinical diagnosis of reproductive disorders, but current methods are hampered by frequent blood sampling coupled to expensive serial immunochemical analysis. Here, we report the development and application of a Robotic APTamer-enabled Electrochemical Reader (RAPTER) electrochemical analysis system to determine LH pulsatility. Through selective evolution of ligands by exponential enrichment (SELEX), we identify DNA aptamers that bind specifically to LH and not to related hormones. The aptamers are integrated into electrochemical aptamer-based (E-AB) sensors on a robotic platform. E-AB enables rapid, sensitive and repeatable determination of LH concentration profiles. Bayesian Spectrum Analysis is applied to determine LH pulsatility in three distinct patient cohorts. This technology has the potential to transform the clinical care of patients with reproductive disorders and could be developed to allow real-time in vivo hormone monitoring.Hong Kong Health and Medical Research Fund (HMRF)National Institute for Health Research (NIHR)University of Hong Kong Outstanding Young Researcher Award 2015-16HKU Seed Fund for Translational and Applied ResearchEngineering and Physical Sciences Research Council (EPSRC)Medical Research Council (MRC
Phylogenetic assessment of heterotrophic bacteria from a water distribution system using 16S rDNA sequencing
No full textDetermination of a heterotrophic plate count (HPC) for drinking-water samples alone is not enough to assess possible health hazards associated with sudden changes in the bacterial count. Speciation is very crucial to determine whether the population includes pathogens and (or) opportunistic pathogens. Most of the isolates recovered from drinking water samples could not be allocated to a specific phylogenetic branch based on the use of conventional diagnostic methods. The present study had to use phylogenetic analysis, which was simplified by determining and using the first 500-bp sequence of the 16S rDNA, to successfully identify the type and species of bacteria found in the samples. Gram-positive bacteria α-, β-, and γ-Proteobacteria were found to be the major groups representing the heterotrophic bacteria in drinking water. The study also revealed that the presence of sphingomonads in drinking water supplies may be much more common than has been reported so far and thus further studies are merited. The intermittent mode of supply, mainly characterized by water stagnation and flow interruption associated possibly with biofilm detachment, raised the possibility that the studied bacterial populations in such systems represented organisms coming from 2 different niches, the biofilm and the water column. © 2005 NRC Canada.Abraham WR, 1999, INT J SYST BACTERIOL, V49, P1053; AMY PS, 1992, APPL ENVIRON MICROB, V58, P3367; Assanta MA, 1998, J FOOD PROTECT, V61, P1321; BEJ AK, 1991, APPL ENVIRON MICROB, V57, P2429; BOTTGER EC, 1989, FEMS MICROBIOL LETT, V65, P171, DOI 10.1016-0378-1097(89)90386-8; Boye K, 1999, MICROBIOL RES, V154, P23; BRAUNHOWLAND EB, 1993, APPL ENVIRON MICROB, V59, P3219; BURKE V, 1984, APPL ENVIRON MICROB, V48, P367; CARSON LA, 1978, APPL ENVIRON MICROB, V36, P839; Chang CT, 2002, APPL ENVIRON MICROB, V68, P3159, DOI 10.1128-AEM.68.6.3159-3161.2002; CLARK J, 1977, CAN J MICROBIOL, V26, P827; Covert TC, 1999, APPL ENVIRON MICROB, V65, P2492; Dewettinck T, 2001, APPL MICROBIOL BIOT, V57, P412, DOI 10.1007-s002530100797; Domingo JWS, 2003, WATER SCI TECHNOL, V47, P149; Fernandez M, 1997, PEDIATR INFECT DIS J, V16, P1007, DOI 10.1097-00006454-199710000-00023; Francis CA, 2001, WATER RES, V35, P3758, DOI 10.1016-S0043-1354(01)00073-2; Furuhata K, 1993, Nihon Koshu Eisei Zasshi, V40, P1047; GELDREICH EE, 1985, J AM WATER WORKS ASS, V77, P72; GILARDI GL, 1984, J CLIN MICROBIOL, V20, P626; HIRAISHI A, 1995, APPL ENVIRON MICROB, V61, P2099; HOLMBERG SD, 1986, ANN INTERN MED, V105, P683; HOLMES B, 1994, J CLIN MICROBIOL, V32, P1970; Holt J. G., 1994, BERGEYS MANUAL DETER; Joseph SW, 2000, ASM NEWS, V66, P218; Kalmbach S, 1999, INT J SYST BACTERIOL, V49, P769; KAYE KM, 1992, CLIN INFECT DIS, V14, P1010; KIM S, 2000, INT J SYST EVOL MICR, V6, P2031; KIROV SM, 1993, INT J FOOD MICROBIOL, V20, P179, DOI 10.1016-0168-1605(93)90164-C; KLINGLER JM, 1992, APPL ENVIRON MICROB, V58, P2089; Kolbert CP, 1999, CURR OPIN MICROBIOL, V2, P299, DOI 10.1016-S1369-5274(99)80052-6; KORVICK JA, 1989, ARCH INTERN MED, V149, P1449, DOI 10.1001-archinte.149.6.1449; Koskinen R, 2000, J APPL MICROBIOL, V89, P687, DOI 10.1046-j.1365-2672.2000.01167.x; Kuhn I, 1997, APPL ENVIRON MICROB, V63, P2708; LANE DJ, 1985, P NATL ACAD SCI USA, V82, P6955, DOI 10.1073-pnas.82.20.6955; Lechevallier M.W., 1980, APPL ENVIRON MICROB, V30, P739; MAKI JS, 1986, APPL ENVIRON MICROB, V51, P1047; Merino S, 1995, INT J FOOD MICROBIOL, V28, P157, DOI 10.1016-0168-1605(95)00054-2; Norton CD, 2000, APPL ENVIRON MICROB, V66, P268; PATT TE, 1976, INT J SYST BACTERIOL, V26, P226; PEARSON WR, 1988, P NATL ACAD SCI USA, V85, P2444, DOI 10.1073-pnas.85.8.2444; Perola O, 2002, J HOSP INFECT, V50, P196, DOI 10.1053-jhin.2001.1163; Pollock TJ, 1999, J IND MICROBIOL BIOT, V23, P436, DOI 10.1038-sj.jim.2900710; REASONER DJ, 1985, APPL ENVIRON MICROB, V49, P1; Rice EW, 2000, J CLIN MICROBIOL, V38, P4296; RUTHERFORD PC, 1988, J CLIN MICROBIOL, V26, P2441; Schubert RHW, 2000, INT J HYG ENVIR HEAL, V203, P83, DOI 10.1078-S1438-4639(04)70012-7; Sekiguchi H, 2002, APPL ENVIRON MICROB, V68, P5142, DOI 10.1128-AEM.68.10.5142-5150.2002; September SM, 2004, APPL ENVIRON MICROB, V70, P7571, DOI 10.1128-AEM.70.12.7571-7573.2004; SPINO DF, 1985, APPL ENVIRON MICROB, V50, P1213; Springer B, 1996, J CLIN MICROBIOL, V34, P296; STACKEBRANDT E, 1988, INT J SYST BACTERIOL, V38, P321; Tang YW, 1998, J CLIN MICROBIOL, V36, P3674; Tokajian S, 2004, WATER QUAL RES J CAN, V39, P64; TOKAJIAN S, 2004, J CHEMOTHERAPY, V16, P104; Tokajian S, 2003, WATER SCI TECHNOL, V47, P229; Tokajian S, 2004, J WATER HEALTH, V2, P115; Ultee A, 2004, J APPL MICROBIOL, V96, P560, DOI 10.1111-j.1365-2672.2004.02174.x; VANDEPEER Y, 1994, COMPUT APPL BIOSCI, V10, P569; Williams MM, 2004, J APPL MICROBIOL, V96, P954, DOI 10.1111-j.1365-2672.2004.02229.x; WINTZINGERODE F, 1999, APPL ENVIRON MICROB, V65, P283; Woo PCY, 2000, J CLIN MICROBIOL, V38, P3515; 1994, MICROBIOLOGICAL EXAM30302
Evaluation of energetic particle parameters in the near-earth magnetotail derived from flux asymmetry observations.
No full textInternational audienceThe flux asymmetries measured by spectrometers on board spacecraft contain information on particle parameters. The net flux intensity (NFI) method provides a tool to evaluate these parameters. The NFI method is valid when both the spin period of the spacecraft and the time resolution of the particle spectrometers are much shorter than the characteristic time-scale of the particle flux variations. We apply the NFI analysis to the flux asymmetry measurements made by GEOS 2 at the nightside geosynchronous orbit in the late substorm growth phase. The cross-tail current of energetic ions, their pressure gradient and average drift velocity, as well as a field-aligned flows are investigated. Current disruption at substorm onset and the "convection surge" mechanism during dipolarization of the magnetic field are directly observed
GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture
No full text\ua9 2023, The Author(s).Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment
