863 research outputs found

    Evidence of functional cell-mediated immune responses to nontypeable Haemophilus influenzae in otitis-prone children

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    Otitis media (OM) remains a common paediatric disease, despite advances in vaccinology. Susceptibility to recurrent acute OM (rAOM) has been postulated to involve defective cell-mediated immune responses to common otopathogenic bacteria. We compared the composition of peripheral blood mononuclear cells (PBMC) from 20 children with a history of rAOM (otitis-prone) and 20 healthy non-otitis-prone controls, and assessed innate and cell-mediated immune responses to the major otopathogen nontypeable Haemophilus influenzae (NTHi). NTHi was a potent stimulator of inflammatory cytokine secretion from PBMC within 4 hours, with no difference in cytokine levels produced between PBMC from cases or controls. In the absence of antigen stimulation, otitis-prone children had more circulating Natural Killer (NK) cells (p<0.01), particularly NKdim (CD56lo) cells (p<0.01), but fewer CD4+ T cells (p<0.01) than healthy controls. NTHi challenge significantly increased the proportion of activated (CD107a+) NK cells in otitis-prone and non-otitis-prone children (p<0.01), suggesting that NK cells from otitis-prone children are functional and respond to NTHi. CD8+ T cells and NK cells from both cases and controls produced IFNÎł in response to polyclonal stimulus (Staphylococcal enterotoxin B; SEB), with more IFNÎł+ CD8+ T cells present in cases than controls (p<0.05) but similar proportions of IFNÎł+ NK cells. Otitis-prone children had more circulating IFNÎł-producing NK cells (p<0.05) and more IFNÎł-producing CD4+ (p<0.01) or CD8+ T-cells (p<0.05) than healthy controls. In response to SEB, more CD107a-expressing CD8+ T cells were present in cases than controls (p<0.01). Despite differences in PBMC composition, PBMC from otitis-prone children mounted innate and T cell-mediated responses to NTHi challenge that were comparable to healthy children. These data provide evidence that otitis-prone children do not have impaired functional cell mediated immunity

    Dickson Charge Pump Rectifier using Ultra-Low Power (ULP) Diode for BAN Applications

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    High power consumption and small battery size severely limit the operating time of devices in Body Area Network (BAN). Radio Frequency (RF) harvesting system can be one of the ways to solve this constraint. Rectifier converts ambient RF into direct current (DC). In a conventional rectifier circuit, Schottky diodes have been considered as an attractive candidate due to their low forward voltage drop and fast switching speed. However, Schottky diodes are not properly modelled in Complementary Metal Oxide Semiconductor (CMOS) technologies which restrict their usefulness in low -cost applications, where high integration levels are desired. Thus, an efficient model of Schottky diode in an integrated circuit (IC) domain is needed. For this reason, Ultra-Low Power (ULP) diode has been proposed in the IC rectifier designs. The performance of ULP diode was compared with diode-connected MOSFET based on Dickson topology and Villard voltage multiplier in 130nm Silterra process technology. The correlation of the design parameters to the performance of voltage rectifier was analysed. The results show that the efficiency of the voltage multiplier has successfully increased more than double based on the optimisation of the design parameters

    Analysis of acoustic emission during the melting of embedded indium particles in an aluminum matrix: a study of plastic strain accommodation during phase transformation

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    Acoustic emission is used here to study melting and solidification of embedded indium particles in the size range of 0.2 to 3 um in diameter and to show that dislocation generation occurs in the aluminum matrix to accommodate a 2.5% volume change. The volume averaged acoustic energy produced by indium particle melting is similar to that reported for bainite formation upon continuous cooling. A mechanism of prismatic loop generation is proposed to accommodate the volume change and an upper limit to the geometrically necessary increase in dislocation density is calculated as 4.1 x 10^9 cm^-2 for the Al-17In alloy. Thermomechanical processing is also used to change the size and distribution of the indium particles within the aluminum matrix. Dislocation generation with accompanied acoustic emission occurs when the melting indium particles are associated with grain boundaries or upon solidification where the solid-liquid interfaces act as free surfaces to facilitate dislocation generation. Acoustic emission is not observed for indium particles that require super heating and exhibit elevated melting temperatures. The acoustic emission work corroborates previously proposed relaxation mechanisms from prior internal friction studies and that the superheat observed for melting of these micron-sized particles is a result of matrix constraint.Comment: Presented at "Atomistic Effects in Migrating Interphase Interfaces - Recent Progress and Future Study" TMS 201

    Markers of cardiac dysfunction in cognitive impairment and dementia

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    Markers of cardiac dysfunction such as amino terminal pro-brain natriuretic peptide (NTpro-BNP) and high sensitivity cardiac troponin T (hs-cTnT) may be associated with dementia. However, limited data exist on their association with either pre-dementia stages, that is, cognitive impairment no dementia (CIND), or the burden of cerebrovascular diseases (CeVD). We therefore, examined the association of these biomarkers of cardiac dysfunction with CeVD in both CIND and dementia. A case–control study, with cases recruited from memory clinics and controls from memory clinics and community. All subjects underwent collection of blood samples, neuropsychological assessment, and neuroimaging. Subjects were classified as CIND and dementia based on clinical criteria whilst significant CeVD was defined as the presence of cortical infarcts and/or more than 2 lacunes and/or confluent white matter lesions in two regions of brain on Age-Related White Matter Changes Scale. We included a total of 35 controls (mean age: 65.9 years), 78 CIND (mean age: 70.2 years) and 80 cases with dementia (mean age: 75.6 years). Plasma concentrations of hs-cTnT were associated significantly with CeVD in both CIND (odds ratios [OR]: 9.05; 95% confidence interval [CI]: 1.64–49.79) and dementia (OR: 16.89; 95%CI: 2.02–142.67). In addition, NTpro-BNP was associated with dementia with CeVD (OR: 7.74; 95%CI: 1.23–48.58). These associations were independent of other vascular risk factors. In this study, we showed that plasma NTproBNP and hs-cTnT are associated with dementia and CIND, only when accompanied by presence of CeVD

    Regulating C<sub>2</sub>H<sub>2</sub>/CO<sub>2</sub> adsorption selectivity by electronic-state manipulation of iron in metal-organic frameworks

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    The separation of C2H2 from C2H2/CO2 mixture is of great importance, yet highly challenging in the petrochemical industry due to their similar physicochemical properties. While open-metal sites (OMSs) in metal-organic frameworks (MOFs) are known to possess high affinity toward C2H2, its selective adsorption performance regulated by the electronic state of the same OMSs remains unexplored. Here, we report a metal electronic-state manipulation approach to construct a pair of isostructural Fe-MOFs, namely LIFM-26(Fe[II]/Fe[III]) and LIFM-27(Fe[III]) with different Fe[II] or Fe[III] oxidation states on the Fe centers, which display mixed-valent Fe[II]/Fe[III] centers in the former and sole Fe[III] centers in the latter. Remarkably, LIFM-26(Fe[II]/Fe[III]) shows significantly enhanced C2H2 uptake capacity than LIFM-27(Fe[III]), attested by adsorption isotherms and IAST calculations, as well as simulated and experimental breakthrough experiments. Furthermore, in situ infrared (IR) and molecular calculations unveil that the presence of Fe[II] in LIFM-26(Fe[II]/Fe[III]) results in stronger Fe[II]–C2H2 interactions than Fe[III]–C2H2, which plays a key role in the C2H2/CO2 separation

    Phylogeny of asian homalomena (Araceae) based on the its region combined with morphological and chemical data

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    A phylogenetic analysis of the genus Homalomena (Araceae: Homalomeneae) based on the nITS region is presented. Eighty-nine taxa are included; representing all Asian supergroups, several Neotropical species currently assigned to Homalomena, and selected species of Philodendron. Asian Homalomena is well supported as monophyletic and excludes Neotropical Homalomena. The Cyrtocladon supergroup is monophyletic after transferring the Insignis complex and Havilandii complex into the Punctulata supergroup. The Homalomena and Chamaecladon supergroups are well supported. A reduced phylogeny of 20 accessions representing 15 taxa was used for subsequent morphological and chemical marker optimization. A constricted spathe and four stamens per staminate flower are plesiomorphic for Homalomena. Staminodes among the pistillate zone are lost three times independently in Homalomena supergroup, Punctulata supergroup, and H. vivens. Chemical markers identified from liquid chromatography-mass spectroscopy profiling provided an independent set of markers that further support the separation of Neotropical species of Homalomena from the Asian taxon. Three chemical markers at Rt 2.55 min, 2.69 min, and 2.90 min are shared among the majority of taxa sampled for Asian Homalomena, and Neotropical species currently assigned to Homalomena show two unique peaks at Rt 3.25 min and 3.54 min. Five chemical markers support the Cyrtocladon supergroup with the exception of Homalomena vivens. A chemical marker at Rt 3.60 min is plesiomorphic for the Chamaecladon, Homalomena and Punctulata supergroups. A chemical marker at Rt 2.80 min is apomorphic for the Chamaecladon supergroup, with a separate gain in H. punctulata. This study supports removal of the Neotropical species from Homalomena, redefines the morphological boundaries of Homalomena sensu stricto (i.e. the Asian species), and supports and refines the grouping of Asian species into supergroups

    The FAITH and HEALTH Trials: Are We Studying Different Hip Fracture Patient Populations?

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    BACKGROUND: Over the past decade, 2 randomized controlled trials were performed to evaluate 2 surgical strategies (internal fixation and arthroplasty) for the treatment of low-energy femoral neck fractures in patients aged ≥50 years. We evaluated whether patient populations in both the FAITH and HEALTH trials had different baseline characteristics and compared the displaced femoral neck fracture cohort from the FAITH trial to HEALTH trial patients. METHODS: Patient demographics, medical comorbidities, and fracture characteristics from both trials were compared. FAITH trial patients with displaced fractures were then compared with HEALTH patients. T-tests and χ tests were performed to compare differences for sex, age, osteoporosis status, and ASA class. RESULTS: The mean age of the 1079 FAITH trial patients was 72 versus 79 years for the 1441 HEALTH trial patients. HEALTH patients were older, mostly White, used more medication, and had more comorbidities than FAITH patients. Of the 1079 FAITH trial patients, 32% (346/1079) had displaced fractures. Their mean age was significantly lower than that of HEALTH patients (66 vs. 79 years; P < 0.001). HEALTH trial patients were significantly more likely to be female, have ASA classification Class III/IV/V, and carry a diagnosis of osteoporosis, as compared with the subgroup of FAITH patients with displaced femoral neck fractures (P < 0.001). CONCLUSION: This study demonstrates significant differences between patients enrolled in the 2 trials. Although both studies focused on femoral neck fractures with similar enrollment criteria, patient

    Low Amplitude Boom-and-Bust Cycles Define the Septoria Nodorum Blotch Interaction

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    Introduction: Septoria nodorum blotch (SNB) is a complex fungal disease of wheat caused by the Dothideomycete fungal pathogen Parastagonospora nodorum. The fungus infects through the use of necrotrophic effectors (NEs) that cause necrosis on hosts carrying matching dominant susceptibility genes. The Western Australia (WA) wheatbelt is a SNB “hot spot” and experiences significant under favorable conditions. Consequently, SNB has been a major target for breeders in WA for many years. Materials and Methods: In this study, we assembled a panel of 155 WA P. nodorum isolates collected over a 44-year period and compared them to 23 isolates from France and the USA using 28 SSR loci. Results: The WA P. nodorum population was clustered into five groups with contrasting properties. 80% of the studied isolates were assigned to two core groups found throughout the collection location and time. The other three non-core groups that encompassed transient and emergent populations were found in restricted locations and time. Changes in group genotypes occurred during periods that coincided with the mass adoption of a single or a small group of widely planted wheat cultivars. When introduced, these cultivars had high scores for SNB resistance. However, the field resistance of these new cultivars often declined over subsequent seasons prompting their replacement with new, more resistant varieties. Pathogenicity assays showed that newly emerged isolates non-core are more pathogenic than old isolates. It is likely that the non-core groups were repeatedly selected for increased virulence on the contemporary popular cultivars. Discussion: The low level of genetic diversity within the non-core groups, difference in virulence, low abundance, and restriction to limited locations suggest that these populations more vulnerable to a population crash when the cultivar was replaced by one that was genetically different and more resistant. We characterize the observed pattern as a low-amplitude boom-and-bust cycle in contrast with the classical high amplitude boom-and-bust cycles seen for biotrophic pathogens where the contrast between resistance and susceptibility is typically much greater. Implications of the results are discussed relating to breeding strategies for more sustainable SNB resistance and more generally for pathogens with NEs

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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