Force-insensitive optical cavity

We describe a rigidly-mounted optical cavity which is insensitive to inertial forces acting in any direction and to the compressive force used to constrain it. The design is based on a cubic geometry with four supports placed symmetrically about the optical axis in a tetrahedral configuration. To measure the inertial force sensitivity, a laser is locked to the cavity while it is inverted about three orthogonal axes. The maximum acceleration sensitivity is 2.5\times10^-11/g (where g=9.81 ms^-2), the lowest passive sensitivity to be reported for an optical cavity.Comment: 3 pages, 3 figures, journa

Associating sporadic, foodborne illness caused by Shiga toxin-producing Escherichia coli with specific foods : a systematic review and meta-analysis of case-control studies

Shiga toxin-producing Escherichia coli (STEC) infections are a significant public health issue, with foodborne transmission causing >1 million illnesses worldwide each year. We conducted a systematic review and meta-analysis (PROSPERO registry # CRD42017074239), to determine the relative association of different food types with sporadic illnesses caused by STEC. Searches were conducted from 01 August to 30 September 2017, using bibliographic and grey literature databases, websites and expert consultation. We identified 22 case-control studies of sporadic STEC infection in humans, from 10 countries within four World Health Organization subregions, from 1985 to 2012. We extracted data from 21 studies, for 237 individual measures in 11 food categories and across three status types (raw or undercooked, not raw and unknown). Beef was the most significant food item associated with STEC illness in the Americas and Europe, but in the Western Pacific region, chicken was most significant. These findings were not significantly moderated by the raw or cooked status of the food item, nor the publication year of the study. Data from the African, South-East Asian and Eastern Mediterranean subregions were lacking and it is unclear whether our results are relevant to these regions

Are the arms and head required to accurately estimate centre of mass motion during running?

Accurate measurement of centre of mass (CoM) motion can provide valuable insight into the biomechanics of human running. However, full-body kinematic measurement protocols can be time consuming and difficult to implement. Therefore, this study was performed to understand whether CoM motion during running could be estimated from a model incorporating only lower extremity, pelvic and trunk segments. Full-body kinematic data was collected whilst (n = 12) participants ran on a treadmill at two speeds (3.1 and 3.9 ms−1). CoM trajectories from a full-body model (16-segments) were compared to those estimated from a reduced model (excluding the head and arms). The data showed that, provided an offset was included, it was possible to accurately estimate CoM trajectory in both the anterior-posterior and vertical direction, with root mean square errors of 5 mm in both directions and close matches in waveform similarity (r = 0.975-1.000). However, in the ML direction, there was a considerable difference in the CoM trajectories of the two models (r = 0.774–0.767). This finding suggests that a full-body model is required if CoM motions are to be measured in the ML direction. The mismatch between the reduced and full-body model highlights the important contribution of the arms to CoM motion in the ML direction. We suggest that this control strategy, of using the arms rather than the heavier trunk segments to generate CoM motion, may lead to less variability in CoM motion in the ML direction and subsequently less variability in step width during human running

Bacteriophages of wastewater foaming-associated filamentous Gordonia reduce host levels in raw activated sludge

Filamentous bacteria are a normal and necessary component of the activated sludge wastewater treatment process, but the overgrowth of filamentous bacteria results in foaming and bulking associated disruptions. Bacteriophages, or phages, were investigated for their potential to reduce the titer of foaming bacteria in a mixed-microbial activated sludge matrix. Foaming-associated filamentous bacteria were isolated from activated sludge of a commercial wastewater treatment plan and identified as Gordonia species by 16S rDNA sequencing. Four representative phages were isolated that target G. malaquae and two un-named Gordonia species isolates. Electron microscopy revealed the phages to be siphophages with long tails. Three of the phages - GordTnk2, Gmala1, and GordDuk1 - had very similar ~76 kb genomes, with >93% DNA identity. These genomes shared limited synteny with Rhodococcus equi phage ReqiDocB7 and Gordonia phage GTE7. In contrast, the genome of phage Gsput1 was smaller (43 kb) and was not similar enough to any known phage to be placed within an established phage type. Application of these four phages at MOIs of 5–15 significantly reduced Gordonia host levels in a wastewater sludge model by approximately 10-fold as compared to non-phage treated reactors. Phage control was observed for nine days after treatment

On Quantum Statistical Inference, I

Recent developments in the mathematical foundations of quantum mechanics have brought the theory closer to that of classical probability and statistics. On the other hand, the unique character of quantum physics sets many of the questions addressed apart from those met classically in stochastics. Furthermore, concurrent advances in experimental techniques and in the theory of quantum computation have led to a strong interest in questions of quantum information, in particular in the sense of the amount of information about unknown parameters in given observational data or accessible through various possible types of measurements. This scenery is outlined (with an audience of statisticians and probabilists in mind).Comment: A shorter version containing some different material will appear (2003), with discussion, in J. Roy. Statist. Soc. B, and is archived as quant-ph/030719

A STUDY ON THE ESTIMATION METHOD OF THE FORM FACTOR FOR A FULL-SCALE SHIP

In this study, a prediction method of the form factor for a full-scale ship is suggested to minimize the power prediction error from a small model ship. Numerical simulations were carried out at various Reynolds numbers from a small model to a full-scale ship. The variation of the form factors was investigated from the results of the numerical simulation according to the Reynolds numbers. In addition, the results from the numerical simulations and experimental data of the geosim models were utilized to drive the correlation line and predict the form factor of a full-scale ship. The correlation line was applied to predict the effective power and the delivered power of a full-scale ship. As a result, the developed prediction method confirmed the possibility of predicting the power reliably from experiments using a small model

In situ formation of silk-gelatin hybrid hydrogels for affinity-based growth factor sequestration and release

Silk fibroin (SF) and gelatin are natural polymers suitable for biomedical applications, including controlled protein release. SF offers high mechanical strength and slow enzymatic degradability, whereas gelatin contains bioactive motifs that can provide biomimicry to the resulting scaffolds. Owing to their complementary material properties, SF and gelatin are increasingly being used together to afford hybrid scaffolds with adjustable properties. Here, we report the use of in situ crosslinked SF/gelatin hydrogels as a platform for tunable growth factor sequestration and delivery. We demonstrate that the physical assembly of SF into insoluble networks could be accelerated by sonication even in the presence of gelatin. However, the processing conditions from which to prepare SF aqueous solution (e.g., heating duration and number of processing steps) drastically altered the resulting hydrogel physical properties. Furthermore, the stiffness of SF/gelatin hybrid gels displayed temperature dependency. Specifically, incorporation of gelatin increased gel stiffness at 25 °C but decreases hydrogel mechanical stability at 37 °C. The thermostability of SF/gelatin gels can be restored by using a low concentration of genipin, a naturally derived chemical crosslinker. We also incorporate heparin-conjugated gelatin (GH) into the hydrogels to create a hybrid matrix capable of sequestering growth factors, such as basic fibroblast growth factor (bFGF). Both sonicated SF (SSF) and hybrid SSF-GH gels exhibit moderate bFGF sequestration, but only SSF-GH gels afford slow release of bFGF. On the other hand, genipin-stabilized network exhibited the highest retention and sustained release of bFGF, suggesting the suitability of this particular formulation as a scaffold for tissue engineering applications

In vivo evaluation of edge-loading in metal-on-metal hip resurfacing patients with pseudotumours

Objectives: Pseudotumours (abnormal peri-prosthetic soft-tissue reactions) following metal-on-metal hip resurfacing arthroplasty (MoMHRA) have been associated with elevated metal ion levels, suggesting that excessive wear may occur due to edge-loading of these MoM implants. This study aimed to quantify in vivo edge-loading in MoMHRA patients with and without pseudotumours during functional activities. Methods: The duration and magnitude of edge-loading in vivo was quantified during functional activities by combining the dynamic hip joint segment contact force calculated from the three-dimensional (3D) motion analysis system with the 3D reconstruction of orientation of the acetabular component and each patient’s specific hip joint centre, based on CT scans. Results: Edge-loading in the hips with pseudotumours occurred with a four-fold increase in duration and magnitude of force compared with the hips without pseudotumours (p = 0.02). Conclusions: The study provides the first in vivo evidence to support that edge-loading is an important mechanism that leads to localised excessive wear (edge-wear), with subsequent elevation of metal ion levels in MoMHRA patients with pseudotumours