•A soft body impact test is developed for large scale delamination in composites.•This test has suitable features, representative of full-scale behaviour.•Experiments were conducted and recorded in ...detail to study delamination.•Fractography revealed insights into crack surface morphology and mode mixity.
High-performance aerospace laminated composite structures manufactured from carbon-fibre prepreg are very susceptible to delamination failure under in-flight impact conditions. Much testing has been conducted at small length scales and quasi-static strain-rates to characterise the delamination performance of different material systems and loading scenarios. Testing at this scale and strain-rate is not representative of the failure conditions experienced by a laminate in a real impact event. Full-scale testing has also been conducted, but much of this is not in the open literature due to intellectual property constraints. Testing at this scale is also prohibitively expensive and involves complex failure mechanisms that cause difficulty in the analysis of associated failure behaviour. A novel test is presented which provides a simple, affordable alternative to full-scale testing but which invokes failure at sufficient scale and velocity to be representative of real component failure. This test design is experimentally validated through a series of soft-body gelatine impact tests using a light gas-gun facility. A fractographic analysis using scanning-electron microscopy was undertaken to examine microscopic failure behaviour, showing a possible reduction in crack mode-ratio during propagation.
Background
Infection control is critical to providing high‐quality patient care. Many veterinary teaching hospitals (VTHs) utilize footbaths or footmats at entrances and key control points throughout ...the facility to decrease trafficking of pathogenic microorganism on contaminated footwear.
Hypothesis/Objectives
To compare efficacy of 4 disinfectants used in footmats for decreasing bacterial contamination of footwear in a large animal hospital.
Animals
A single adult dairy cow was housed in a stall for 4 days to facilitate stall contamination with fecal material.
Methods
Overboots were experimentally contaminated with organic material in a standardized manner. Each boot was randomly assigned to 1 of 5 treatments (no treatment, or exposure to 1 of 4 disinfectants: an accelerated peroxygen AHP, a peroxygen VIRKON, a quaternary ammonium QUAT, and a phenolic disinfectant PHENOLIC) by stepping on a soaked footmat and collecting samples from boot soles. Generalized linear modeling was used to analyze differences in bacterial counts.
Results
Reductions in colony‐forming units (CFUs) on treated boots ranged from no detectable reduction to 0.45 log10 and varied by disinfectant. Percentage reductions in total bacterial counts generally were larger (albeit still modest) for AHP and QUAT disinfectants (range 37–45%) and smallest for the PHENOLIC (no detectable reduction).
Conclusions and Clinical Importance
In general, use of disinfectant footmats was associated with significant reductions in viable bacteria on overboots—albeit with variable efficacy. Footmats may be useful adjuncts to cleaning and disinfection programs for decreasing trafficking of microorganisms throughout VTHs but should not be considered as a sole prevention method.
Summary
Reasons for performing study
Effective decontamination of animal holding environments is critical for providing high quality patient care and maintaining a safe working environment. ...Disinfection of animal holding environments is a significant challenge during times of epidemic disease.
Objectives
The purpose of this study was to evaluate the disinfectant efficacy of 3 strategies for high‐volume directed mist application of accelerated hydrogen peroxide and peroxymonosulfate disinfectants; 4.25% accelerated hydrogen peroxide (Accel®; AHP) at a 1:16 dilution and single and double applications of 2% peroxymonosulfate solution (Virkon‐S®; VIR‐1 and VIR‐2) for decontamination of a large animal hospital environment.
Study design
Experiment.
Methods
After cleaning and disinfection of the hospital environment, transparencies experimentally contaminated with known concentrations of Staphylococcus aureus, Salmonella enterica and Pseudomonas aeruginosa were placed on vertical surfaces. Disinfectant solution was applied by directed mist application and, after 30 min of contact time, transparencies were collected and individually placed into tubes containing 10 ml Dey‐Engley broth. The process was repeated for each disinfectant. Tenfold dilutions of each sample were plated onto tryptic soy blood agar with 5% sheep blood. Bacterial counts from transparencies exposed to disinfectants were compared with counts from control transparencies (unexposed to disinfectants) to evaluate reduction in colony forming units.
Results
The least squares mean reduction (log10) in colony forming units (CFUs) for S. aureus and P. aeruginosa was 1.5–2.5 logs and approximately 0.8–1.0 logs for S. enterica. Reductions were generally largest for VIR‐2 and smallest for AHP, although these differences were not all statistically significant and the magnitude of differences may not be clinically relevant.
Conclusions
For the organisms evaluated, all 3 disinfectants applied as a directed mist were effective at reducing CFUs in a veterinary hospital environment. Effective disinfection using this method of application is dependent on adequate cleaning prior to application, and use of adequate volumes of disinfectant.
Significant research exists on small-scale, quasi-static failure behaviour of Z-pinned composite laminates. However, little work has been conducted on large-scale, high strain-rate behaviour of ...Z-pinned composites at structural level. Small-scale testing is often at an insufficient scale to invoke the full crack bridging effects of the Z-pins. Full-scale testing on real components involves large length scales, complex geometries and resulting failure mechanisms that make it difficult to identify the specific effect of Z-pins on the component failure behaviour. A novel cantilever soft body impact test has been developed which is of sufficient scale to invoke large-scale delamination, such that behaviour in Z-pin arrays at high strain-rates can be studied. Laminates containing Z-pin arrays were subjected to soft-body gelatine impact in high-speed light gas-gun tests. Detailed fractographic investigation was carried out to investigate the dynamic failure behaviour of Z-pins at the microscopic scale.
Despite being one of the most studied proteases in bacteria, very little is known about the role of ClpXP in mitochondria. We now present evidence that mammalian CLPP has an essential role in ...determining the rate of mitochondrial protein synthesis by regulating the level of mitoribosome assembly. Through a proteomic approach and the use of a catalytically inactive CLPP, we produced the first comprehensive list of possible mammalian ClpXP substrates involved in the regulation of mitochondrial translation, oxidative phosphorylation, and a number of metabolic pathways. We further show that the defect in mitoribosomal assembly is a consequence of the accumulation of ERAL1, a putative 12S rRNA chaperone, and novel ClpXP substrate. The presented data suggest that the timely removal of ERAL1 from the small ribosomal subunit is essential for the efficient maturation of the mitoribosome and a normal rate of mitochondrial translation.
Synopsis
A combination of proteomics and mouse knockout approaches identifies substrates of the mammalian ClpXP protease, showing that it controls mitochondrial homeostasis by ensuring assembly and function of mitochondrial ribosomes.
Mammalian ClpXP substrates are involved in mitochondrial translation, oxidative phosphorylation, and metabolism.
ClpXP determines the rate of mitochondrial protein synthesis by regulating the level of mitoribosome assembly.
Timely removal of ERAL1 from the small ribosomal subunit is essential for the efficient maturation of the mitoribosome and a normal rate of mitochondrial translation.
A combination of proteomics and mouse knockout approaches identifies substrates of the mammalian ClpXP protease, showing that it controls mitochondrial homeostasis by ensuring assembly and function of mitochondrial ribosomes.
Context:
Only approximately 85% of patients with a clinical diagnosis complete androgen insensitivity syndrome and less than 30% with partial androgen insensitivity syndrome can be explained by ...inactivating mutations in the androgen receptor (AR) gene.
Objective:
The objective of the study was to clarify this discrepancy by in vitro determination of AR transcriptional activity in individuals with disorders of sex development (DSD) and male controls.
Design:
Quantification of DHT-dependent transcriptional induction of the AR target gene apolipoprotein D (APOD) in cultured genital fibroblasts (GFs) (APOD assay) and next-generation sequencing of the complete coding and noncoding AR locus.
Setting:
The study was conducted at a university hospital endocrine research laboratory.
Patients:
GFs from 169 individuals were studied encompassing control males (n = 68), molecular defined DSD other than androgen insensitivity syndrome (AIS; n = 18), AR mutation-positive AIS (n = 37), and previously undiagnosed DSD including patients with a clinical suspicion of AIS (n = 46).
Intervention(s):
There were no interventions.
Main Outcome Measure(s):
DHT-dependent APOD expression in cultured GF and AR mutation status in 169 individuals was measured.
Results:
The APOD assay clearly separated control individuals (healthy males and molecular defined DSD patients other than AIS) from genetically proven AIS (cutoff < 2.3-fold APOD-induction; 100% sensitivity, 93.3% specificity, P < .0001). Of 46 DSD individuals with no AR mutation, 17 (37%) fell below the cutoff, indicating disrupted androgen signaling.
Conclusions:
AR mutation-positive AIS can be reliably identified by the APOD assay. Its combination with next-generation sequencing of the AR locus uncovered an AR mutation-negative, new class of androgen resistance, which we propose to name AIS type II. Our data support the existence of cellular components outside the AR affecting androgen signaling during sexual differentiation with high clinical relevance.
The use of Apolipoprotein D as a biomarker for androgen sensitivity identifies a new type of androgen insensitivity syndrome that is not associated with a mutation in the androgen receptor gene.
We present a hexagonal boron nitride (hBN) polymer-assisted transfer technique and discuss subtleties about the process. We then demonstrate localized emission from strained regions of the film ...draped over features on a prepatterned substrate. Notably, we provide insight into the brightness distribution of these emitters and show that the brightest emission is clearly localized to the underlying substrate features rather than unintentional wrinkles present in the hBN film. Our results aide in the current discussion surrounding scalability of single photon emitter arrays.
Prenatal fever and autism risk Hornig, M; Bresnahan, M A; Che, X ...
Molecular psychiatry,
03/2018, Letnik:
23, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Some studies suggest that prenatal infection increases risk of autism spectrum disorders (ASDs). This study was undertaken in a prospective cohort in Norway to examine whether we could find evidence ...to support an association of the prenatal occurrence of fever, a common manifestation of infection, with ASD risk. Prospective questionnaires provided maternal exposure data; case status was established from clinical assessments and registry linkages. In a large, prospectively ascertained cohort of pregnant mothers and their offspring, we examined infants born ⩾32 weeks for associations between fever exposure in each trimester and ASD risk using logistic regression. Maternal exposure to second-trimester fever was associated with increased ASD risk, adjusting for presence of fever in other trimesters and confounders (adjusted odds ratio (aOR), 1.40; 95% confidence interval, 1.09-1.79), with a similar, but nonsignificant, point estimate in the first trimester. Risk increased markedly with exposure to three or more fever episodes after 12 weeks' gestation (aOR, 3.12; 1.28-7.63). ASD risk appears to increase with maternal fever, particularly in the second trimester. Risk magnified dose dependently with exposure to multiple fevers after 12 weeks' gestation. Our findings support a role for gestational maternal infection and innate immune responses to infection in the pathogenesis of at least some cases of ASD.
We describe the use of monolithic, buckled-dome cavities as ultrasound sensors. Patterned delamination within a compressively stressed thin film stack produces high-finesse plano-concave optical ...resonators with sealed and empty cavity regions. The buckled mirror also functions as a flexible membrane, highly responsive to changes in external pressure. Owing to their efficient opto-acousto-mechanical coupling, thermal-displacement-noise limited sensitivity is achieved at low optical interrogation powers and for modest optical (
Q
∼ 10
3
) and mechanical (
Q
∼ 10
2
) quality factors. We predict and verify broadband (up to ∼ 5 MHz), air-coupled ultrasound detection with noise-equivalent pressure (NEP) as low as ∼ 30-100 µPa/Hz
1/2
. This corresponds to an ultrasonic force sensitivity ∼ 2 × 10
−13
N/Hz
1/2
and enables the detection of MHz-range signals propagated over distances as large as ∼ 20 cm in air. In water, thermal-noise-limited sensitivity is demonstrated over a wide frequency range (up to ∼ 30 MHz), with NEP as low as ∼ 100-800 µPa/Hz
1/2
. These cavities exhibit a nearly omnidirectional response, while being ∼ 3-4 orders of magnitude more sensitive than piezoelectric devices of similar size. Easily realized as large arrays and naturally suited to direct coupling by free-space beams or optical fibers, they offer significant practical advantages over competing optical devices, and thus could be of interest for several emerging applications in medical and industrial ultrasound imaging.
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