Structure-property relationships in glass-reinforced polyamide, part 1: The effects of fiber content

We present the results of an extensive study of the performance of injection-molded glass-fiber reinforced polyamide 66 with glass content between 0 and 40% and based on two chopped glass products both sized with polyamide compatible sizing. Mechanical properties generally improved with increasing glass content, modulus linearly, strength with a maximum at 40-50% glass content, and impact showing an initial decrease from the resin value with a minimum at 4% glass content before increasing at higher glass contents. Residual fiber length decreased linearly with increasing glass content. Interfacial strength was found to be in the range of 30-36 MPa, and no significant differences in dry as molded performance was found between the 123D and 173X sizings. Conditioning these composites in either boiling water or water/glycol mixtures leads to a dramatic drop in both tensile modulus and tensile strength. This is most likely due to the high level of matrix plasticization. After conditioning, the 173X sized glass delivered a significantly higher level of tensile elongation at all fiber contents. Excellent agreement was obtained between the experimental data and the theoretical predictions of the rule of mixtures model for modulus and the Kelly-Tyson model for strength over the range of fiber concentrations studied

Posterior cricoid region fluoroscopic findings: the posterior cricoid plication.

The region posterior to the cricoid cartilage is challenging to assess fluoroscopically. The purpose of this investigation is to critically evaluate the posterior cricoid (PC) region on fluoroscopy and describe patterns of common findings. This was a case control study. All fluoroscopic swallowing studies performed between June 16, 2009, and February 9, 2010, were reviewed for features seen in the PC region. These findings were categorized into distinct patterns and compared to fluoroscopic studies performed in a cohort of normal volunteers. Two hundred patient studies and 149 healthy volunteer studies were reviewed. The mean age of the referred patient cohort and the volunteer cohort was 57 years (±19) and 61 years (±16), respectively (p > 0.05). The patient cohort was 53% male and the control cohort was 56% female (p > 0.05). Four groups were identified. Pharyngoesophageal webs were seen in 7% (10/149) of controls and 14% (28/200) of patients (p = 0.03). A PC arch impression was seen in 16% of patients (32/200) and controls (24/149) (p = 1). A PC plication was demonstrated in 23% (34/149) of controls and 30% (60/200) of patients (p = 0.13). No distinctive PC region findings were seen in 54% (81/149) of controls and 42% (84/200) of referred patients (p = 0.02). Four patients (2%) had both a web and a PC plication. Four categories of PC region findings were identified (unremarkable PC region, web, PC arch impression, and PC plication). Both patients referred for swallowing studies and healthy volunteers demonstrated esophageal webs, PC arch impressions, and PC plications. Only webs were more common in patients than in control subjects (p = 0.03). The PC impression and PC plication are likely to represent normal variants that may be identified on fluoroscopic swallow studies

Fixed-point spectrum for group actions by affine isometries on Lp-spaces

The fixed-point spectrum of a locally compact second countable group G on lp is defined to be the set of real numbers p such that every action by affine isometries of G on lp admits a fixed-point. We show that this set is either empty, or is equal to a set of one of the following forms : [1,\pc[, [1,\pc[\{2} for some \pc<\infty or \pc=\infty, or [1,\pc], [1,\pc]\{2} for some pc<infty. This answers a question closely related to a conjecture of C. Drutu which asserts that the fixed-point spectrum is connected for isometric actions on Lp(0,1). We also study the topological properties of the fixed-point spectrum on Lp(X,\mu) for general measure spaces (X,\mu), and show partial results toward the conjecture for actions on Lp(0,1). In particular, we prove that the spectrum F_{L^{\infty}(X,\mu)(G,\pi) of actions with linear part \pi is either empty, or an interval of the form [1,\pc] or [1,\infty[, whenever \pi is an orthogonal representation associated to a measure-preserving ergodic action on a finite measure space (X,\mu).Comment: 25 page

Phosphocholine-Modified Lipooligosaccharides of Haemophilus influenzae Inhibit ATP-Induced IL-1beta Release by Pulmonary Epithelial Cells

Phosphocholine-modified bacterial cell wall components are virulence factors enabling immune evasion and permanent colonization of the mammalian host, by mechanisms that are poorly understood. Recently, we demonstrated that free phosphocholine (PC) and PC-modified lipooligosaccharides (PC-LOS) from Haemophilus influenzae, an opportunistic pathogen of the upper and lower airways, function as unconventional nicotinic agonists and efficiently inhibit the ATP-induced release of monocytic IL-1beta. We hypothesize that H. influenzae PC-LOS exert similar effects on pulmonary epithelial cells and on the complex lung tissue. The human lung carcinoma-derived epithelial cell lines A549 and Calu-3 were primed with lipopolysaccharide from Escherichia coli followed by stimulation with ATP in the presence or absence of PC or PC-LOS or LOS devoid of PC. The involvement of nicotinic acetylcholine receptors was tested using specific antagonists. We demonstrate that PC and PC-LOS efficiently inhibit ATP-mediated IL-1beta release by A549 and Calu-3 cells via nicotinic acetylcholine receptors containing subunits alpha7, alpha9, and/or alpha10. Primed precision-cut lung slices behaved similarly. We conclude that H. influenzae hijacked an endogenous anti-inflammatory cholinergic control mechanism of the lung to evade innate immune responses of the host. These findings may pave the way towards a host-centered antibiotic treatment of chronic airway infections with H. influenzae

The Origin of OB Clusters: From 10 pc to 0.1 pc

We observe the 1.2 mm continuum emission around the OB cluster forming region G10.6-0.4, using the IRAM 30m telescope MAMBO-2 bolometer array and the Submillimeter array. Comparison of the Spitzer 24 $\mu$m and 8 $\mu$m images with our 1.2 mm continuum maps reveals the ionization front of an HII region, the photon-dominated layer, and several 5 pc scale filaments following the outer edge of the photon-dominated layer. The filaments, which are resolved in the MAMBO-2 observations, show regularly spaced parsec-scale molecular clumps, embedded with a cluster of submillimeter molecular cores as shown in the SMA 0.87 mm observations. Toward the center of the G10.6-0.4 region, the combined SMA+IRAM 30m continuum image reveals several, parsec-scale protrusions. They may continue down to within 0.1 pc of the geometric center of a dense 3 pc size structure, where a 200 M$_{\odot}$ OB cluster resides. The observed filaments may facilitate mass accretion onto the central cluster--forming region in the presence of strong radiative and mechanical stellar feedbacks. Their filamentary geometry may also facilitate fragmentation. We did not detect any significant polarized emission at 0.87 mm in the inner 1 pc region with the SMA.Comment: 32 pages, 10 figures, Accepted by ApJ on 2011.October

Period-colour and amplitude-colour relations in classical Cepheid variables IV: The multi-phase relations

The superb phase resolution and quality of the OGLE data on LMC and SMC Cepheids, together with existing data on Galactic Cepheids, are combined to study the period-colour (PC) and amplitude-colour (AC) relations as a function of pulsation phase. Our results confirm earlier work that the LMC PC relation (at mean light) is more consistent with two lines of differing slopes, separated at a period of 10 days. However, our multi-phase PC relations reveal much new structure which can potentially increase our understanding of Cepheid variables. These multi-phase PC relations provide insight into why the Galactic PC relation is linear but the LMC PC relation is non-linear. This is because the LMC PC relation is shallower for short (log P < 1) and steeper for long (log P > 1) period Cepheids than the corresponding Galactic PC relation. Both of the short and long period Cepheids in all three galaxies exhibit the steepest and shallowest slopes at phases around 0.75-0.85, respectively. A consequence is that the PC relation at phase ~0.8 is highly non-linear. Further, the Galactic and LMC Cepheids with log P > 1 display a flat slope in the PC plane at phases close to the maximum light. When the LMC period-luminosity (PL) relation is studied as a function of phase, we confirm that it changes with the PC relation. The LMC PL relation in V- and I-band near the phase of 0.8 provides compelling evidence that this relation is also consistent with two lines of differing slopes joined at a period close to 10 days.Comment: 12 pages, 1 table and 13 figures, MNRAS accepte

Roots of Ehrhart polynomials of Gorenstein Fano polytopes

Given arbitrary integers $k$ and $d$ with $0 \leq 2k \leq d$, we construct a Gorenstein Fano polytope \Pc \subset \RR^d of dimension $d$ such that (i) its Ehrhart polynomial i(\Pc, n) possesses $d$ distinct roots; (ii) i(\Pc, n) possesses exactly $2k$ imaginary roots; (iii) i(\Pc, n) possesses exactly $d - 2k$ real roots; (iv) the real part of each of the imaginary roots is equal to $- 1 / 2$; (v) all of the real roots belong to the open interval $(-1, 0)$.Comment: 6 page

Extent of hypoattenuation on CT angiography source images in Basilar Artery occlusion: prognostic value in the Basilar Artery International Cooperation Study

&lt;p&gt;&lt;b&gt;Background and Purpose:&lt;/b&gt; The posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) quantifies the extent of early ischemic changes in the posterior circulation with a 10-point grading system. We hypothesized that pc-ASPECTS applied to CT angiography source images predicts functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; BASICS was a prospective, observational registry of consecutive patients with acute symptomatic basilar artery occlusion. Functional outcome was assessed at 1 month. We applied pc-ASPECTS to CT angiography source images of patients with CT angiography for confirmation of basilar artery occlusion. We calculated unadjusted and adjusted risk ratios (RRs) of pc-ASPECTS dichotomized at &#8805;8 versus &#60;8. Primary outcome measure was favorable outcome (modified Rankin Scale scores 0–3). Secondary outcome measures were mortality and functional independence (modified Rankin Scale scores 0–2).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; Of 158 patients included, 78 patients had a CT angiography source images pc-ASPECTS ≥8. Patients with a pc-ASPECTS ≥8 more often had a favorable outcome than patients with a pc-ASPECTS &#60;8 (crude RR, 1.7; 95% CI, 0.98–3.0). After adjustment for age, baseline National Institutes of Health Stroke Scale score, and thrombolysis, pc-ASPECTS &#8805;8 was not related to favorable outcome (RR, 1.3; 95% CI, 0.8–2.2), but it was related to reduced mortality (RR, 0.7; 95% CI, 0.5–0.98) and functional independence (RR, 2.0; 95% CI, 1.1–3.8). In post hoc analysis, pc-ASPECTS dichotomized at &#8805;6 versus &#60;6 predicted a favorable outcome (adjusted RR, 3.1; 95% CI, 1.2–7.5).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; pc-ASPECTS on CT angiography source images independently predicted death and functional independence at 1 month in the CT angiography subgroup of patients in the BASICS registry.&lt;/p&gt