100 research outputs found
Bulk viscosity in the nonlinear and anharmonic regime of strange quark matter
The bulk viscosity of cold, dense three-flavor quark matter is studied as a
function of temperature and the amplitude of density oscillations. The study is
also extended to the case of two different types of anharmonic oscillations of
density. We point several qualitative effects due to the anharmonicity,
although quantitatively they appear to be relatively small. We also find that,
in most regions of the parameter space, with the exception of the case of a
very large amplitude of density oscillations (i.e. 10% and above), nonlinear
effects and anharmonicity have a small effect on the interplay of the
nonleptonic and semileptonic processes in the bulk viscosity.Comment: 14 pages, 6 figures; v2: Appendix B is omitted, a few new discussions
added and some new references adde
Effect of Quorum Sensing by Staphylococcus epidermidis on the Attraction Response of Female Adult Yellow Fever Mosquitoes, Aedes aegypti aegypti (Linnaeus) (Diptera: Culicidae), to a Blood-Feeding Source
Aedes aegypti, the principal vector of yellow fever and dengue fever, is responsible for more than 30,000 deaths annually. Compounds such as carbon dioxide, amino acids, fatty acids and other volatile organic compounds (VOCs) have been widely studied for their role in attracting Ae. aegypti to hosts. Many VOCs from humans are produced by associated skin microbiota. Staphyloccocus epidermidis, although not the most abundant bacteria according to surveys of relative 16S ribosomal RNA abundance, commonly occurs on human skin. Bacteria demonstrate population level decision-making through quorum sensing. Many quorum sensing molecules, such as indole, volatilize and become part of the host odor plum. To date, no one has directly demonstrated the link between quorum sensing (i.e., decision-making) by bacteria associated with a host as a factor regulating arthropod vector attraction. This study examined this specific question with regards to S. epidermidis and Ae. aegypti. Pairwise tests were conducted to examine the response of female Ae. aegypti to combinations of tryptic soy broth (TSB) and S. epidermidis wildtype and agr- strains. The agr gene expresses an accessory gene regulator for quorum sensing; therefore, removing this gene inhibits quorum sensing of the bacteria. Differential attractiveness of mosquitoes to the wildtype and agr- strains was observed. Both wildtype and the agr- strain of S. epidermidis with TSB were marginally more attractive to Ae. aegypti than the TSB alone. Most interestingly, the blood-feeder treated with wildtype S. epidermidis/TSB attracted 74% of Ae. aegypti compared to the agr- strain of S. epidermidis/TSB (P †0.0001). This study is the first to suggest a role for interkingdom communication between host symbiotic bacteria and mosquitoes. This may have implications for mosquito decision-making with regards to host detection, location and acceptance. We speculate that mosquitoes "eavesdrop" on the chemical discussions occurring between host-associated microbes to determine suitability for blood feeding. We believe these data suggest that manipulating quorum sensing by bacteria could serve as a novel approach for reducing mosquito attraction to hosts, or possibly enhancing the trapping of adults at favored oviposition sites
Cross-talk between PRMT1-mediated methylation and ubiquitylation on RBM15 controls RNA splicing
RBM15, an RNA binding protein, determines cell-fate specification of many tissues including blood. We demonstrate that RBM15 is methylated by protein arginine methyltransferase 1 (PRMT1) at residue R578 leading to its degradation via ubiquitylation by an E3 ligase (CNOT4). Overexpression of PRMT1 in acute megakaryocytic leukemia cell lines blocks megakaryocyte terminal differentiation by downregulation of RBM15 protein level. Restoring RBM15 protein level rescues megakaryocyte terminal differentiation blocked by PRMT1 overexpression. At the molecular level, RBM15 binds to pre-mRNA intronic regions of genes important for megakaryopoiesis such as GATA1, RUNX1, TAL1 and c-MPL. Furthermore, preferential binding of RBM15 to specific intronic regions recruits the splicing factor SF3B1 to the same sites for alternative splicing. Therefore, PRMT1 regulates alternative RNA splicing via reducing RBM15 protein concentration. Targeting PRMT1 may be a curative therapy to restore megakaryocyte differentiation for acute megakaryocytic leukemia
Deletion of Asxl1 results in myelodysplasia and severe developmental defects in vivo
Somatic Addition of Sex Combs Like 1 (ASXL1) mutations occur in 10-30% of patients with myeloid malignancies, most commonly in myelodysplastic syndromes (MDSs), and are associated with adverse outcome. Germline ASXL1 mutations occur in patients with Bohring-Opitz syndrome. Here, we show that constitutive loss of Asxl1 results in developmental abnormalities, including anophthalmia, microcephaly, cleft palates, and mandibular malformations. In contrast, hematopoietic-specific deletion of Asxl1 results in progressive, multilineage cytopenias and dysplasia in the context of increased numbers of hematopoietic stem/progenitor cells, characteristic features of human MDS. Serial transplantation of Asxl1-null hematopoietic cells results in a lethal myeloid disorder at a shorter latency than primary Asxl1 knockout (KO) mice. Asxl1 deletion reduces hematopoietic stem cell self-renewal, which is restored by concomitant deletion of Tet2, a gene commonly co-mutated with ASXL1 in MDS patients. Moreover, compound Asxl1/Tet2 deletion results in an MDS phenotype with hastened death compared with single-gene KO mice. Asxl1 loss results in a global reduction of H3K27 trimethylation and dysregulated expression of known regulators of hematopoiesis. RNA-Seq/ChIP-Seq analyses of Asxl1 in hematopoietic cells identify a subset of differentially expressed genes as direct targets of Asxl1. These findings underscore the importance of Asxl1 in Polycomb group function, development, and hematopoiesisclos
A soft pressure sensor skin for hand and wrist orthoses
Side effects caused by excessive contact pressure such as discomfort and pressure sores are commonly complained by patients wearing orthoses. These problems leading to low patient compliance decrease the effectiveness of the device. To mitigate side effects, this study describes the design and fabrication of a soft sensor skin with strategically placed 12 sensor units for static contact pressure measurement beneath a hand and wrist orthosis. A Finite Element Model was built to simulate the pressure on the hand of a subject and sensor specifications were obtained from the result to guide the design. By testing the fabricated soft sensor skin on the subject, contact pressure between 0.012 MPa and 0.046 MPa was detected, revealing the maximum pressure at the thumb metacarpophalangeal joint which was the same location of the highest pressure of simulation. In this letter, a new fabrication method combining etching and multi-material additive manufacture was introduced to produce multiple sensor units as a whole. Furthermore, a novel fish-scale structure as the connection among sensors was introduced to stabilize sensor units and reinforce the soft skin. Experimental analysis reported that the sensor signal is repeatable, and the fish-scale structure facilitates baseline resuming of sensor signal during relaxation
Aggregationâinduced emission featured supramolecular tubisomes for imagingâguided drug delivery
Aggregation-induced emission featured cylindrical polymeric nanoparticles (tubisomes) are obtained from the hierarchical self-assembly of an amphiphilic cyclic peptide polymer conjugate. Intriguingly, encapsulation of the anticancer drug doxorubicin (DOX) can inactivate the fluorescence of both tubisome and DOX due to the energy transfer relay (ETR). The release of DOX can interrupt the ETR effect and light up the silenced fluorescence, thereby permitting the in-situ visualization of drug release
Cartilage quantitative T2 relaxation time 2â4 years following isolated anterior cruciate ligament reconstruction
Cartilage T2 relaxation time in isolated anterior cruciate ligament reconstruction (ACLR) without concomitant meniscal pathology and their changes over time remain unclear. The purpose of this exploratory study was to: (i) compare cartilage T2 relaxation time (T2 values) in people with isolated ACLR at 2â3 years postâsurgery (baseline) and matched healthy controls and; (ii) evaluate the subsequent 2âyear change in T2 values in people with ACLR. Twentyâeight participants with isolated ACLR and nine healthy volunteers underwent knee magnetic resonance imaging (MRI) at baseline; 16 ACLR participants were reâimaged 2 years later. Cartilage T2 values in full thickness, superficial layers, and deep layers were quantified in the tibia, femur, trochlear, and patella. Betweenâgroup comparisons at baseline were performed using analysis of covariance adjusting for age, sex, and body mass index. Changes over time in the ACLR group were evaluated using paired sample tâtests. ACLR participants showed significantly higher (pâ=â0.03) T2 values in the deep layer of medial femoral condyle at baseline compared to controls (mean difference 4.4âms [13%], 95%CI 0.4, 8.3âms). Over 2 years, ACLR participants showed a significant reduction (pâ=â0.04) in T2 value in the deep layer of lateral tibia (mean change 1.4âms [â7%], 95%CI 0.04, 2.8âms). The decrease in T2 values suggests improvement in cartilage composition in the lateral tibia (deep layer) of ACLR participants. Further research with larger ACLR cohorts divided according to meniscal status and matched healthy cohorts are needed to further understand cartilage changes postâACLR. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1â8, 2018.Full Tex
Mean number (A) and (B) percent of 5-8-d-old adult female <i>Ae</i>. <i>aegypti</i> mosquitos attracted per minute ± SEM to blood-feeders treated with TSB located on the right and left sides of the top of a 82 cm x 45 cm x 52 cm Plexiglas cage during 15-min trials (N<sup>1</sup> = 4; n<sup>2</sup> = 50) at approximately 25°C and 80% RH.
<p><sup>1</sup>number of trials conducted; <sup>2</sup>number of mosquitoes used in a trial.</p
Repeated G test of goodness-of-fit test, percent response per trial, and mean percent ± SEM across trials of the response of 5-8-d old <i>Ae</i>. <i>aegypti</i> (N<sup>1</sup> = 4; n<sup>2</sup> = 50) adult female attraction to blood-feeders located on opposite sides of the top of a 82 cm x 45 cm x 52 cm Plexiglas cage during 15-min experiments at 25°C and 80% RH and treated with <i>agr-</i> mutant <i>S</i>. <i>epidermidis/</i>TSB or solely TSB.
<p><sup>1</sup>number of trials conducted</p><p><sup>2</sup>number of mosquitoes used in a trial</p><p><sup>a</sup>Total number of mosquitoes to respond</p><p>Repeated G test of goodness-of-fit test, percent response per trial, and mean percent ± SEM across trials of the response of 5-8-d old <i>Ae</i>. <i>aegypti</i> (N<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143950#t003fn001" target="_blank"><sup>1</sup></a> = 4; n<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143950#t003fn002" target="_blank"><sup>2</sup></a> = 50) adult female attraction to blood-feeders located on opposite sides of the top of a 82 cm x 45 cm x 52 cm Plexiglas cage during 15-min experiments at 25°C and 80% RH and treated with <i>agr-</i> mutant <i>S</i>. <i>epidermidis/</i>TSB or solely TSB.</p
Mean number (A) and (B) percent of 5-8-d-old adult female <i>Ae</i>. <i>aegypti</i> mosquito attraction per minute ± SEM to blood-feeders treated with TSB or <i>agr- S</i>. <i>epidermidis</i>/TSB located on the right and left sides of the top of a 82 cm x 45 cm x 52 cm Plexiglas cage during 15-min trials (N<sup>1</sup> = 4; n<sup>2</sup> = 50) at approximately 25°C and 80% RH.
<p><sup>1</sup>number of trials conducted; <sup>2</sup>number of mosquitoes used in a trial.</p
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