Critical Behavior and Axis Defining Symmetry Breaking in Hydra Embryonic Development

The formation of a hollow cellular sphere is often one of the first steps of multicellular embryonic development. In the case of Hydra, the sphere breaks its initial symmetry to form a foot-head axis. During this process a gene, ks1, is increasingly expressed in localized cell domains whose size distribution becomes scale-free at the axis-locking moment. We show that a physical model based solely on the production and exchange of ks1-promoting factors among neighboring cells robustly reproduces the scaling behavior as well as the experimentally observed spontaneous and temperature-directed symmetry breaking.

On-axis joint transform correlation based on a four-level power spectrum

We propose a method to obtain a single centered correlation with use of a joint transform correlator. We analyze the required setup to carry out the whole process optically, and we also present experimental results.

Rapid disease emergence through horizontal gene transfer between eukaryotes.

Among different species of eukaryotes, the extent and evolutionary significance of horizontal gene transfer remains poorly understood. A newly published study by Friesen and colleagues indicates that a recent gene transfer between two species of fungi has enabled the recipient to rapidly acquire high virulence on wheat. The study highlights a mechanism by which diseases can suddenly emerge, but also brings up the controversial issues of how horizontal gene transfer occurs and whether fungal incompatibility barriers to gene flow are more 'leaky' than was previously thought.

Wind Monitoring of the Saylorville and Red Rock Reservoir Bridges with Remote, Cellular-Based Notifications, May 2012

Following a high wind event on January 24, 2006, at least five people claimed to have seen or felt the superstructure of the Saylorville Reservoir Bridge in central Iowa moving both vertically and laterally. Since that time, the Iowa Department of Transportation (DOT) contracted with the Bridge Engineering Center at Iowa State University to design and install a monitoring system capable of providing notification of the occurrence of subsequent high wind events. In subsequent years, a similar system was installed on the Red Rock Reservoir Bridge to provide the same wind monitoring capabilities and notifications to the Iowa DOT. The objectives of the system development and implementation are to notify personnel when the wind speed reaches a predetermined threshold such that the bridge can be closed for the safety of the public, correlate structural response with wind-induced response, and gather historical wind data at these structures for future assessments. This report describes the two monitoring systems, their components, upgrades, functionality, and limitations, and results from one year of wind data collection at both bridges.

On the spinning axis representation

A new spinning axis representation is introduced. It allows us to calculate the evolution operator of a system with slowly varying time dependent Hamiltonian with the desired degree of approximation in the parameter used for describing its dynamical evolution. The procedure is compared with a previously existing one and applied to a simple example.

Wind Monitoring of the Saylorville and Red Rock Reservoir Bridges with Remote, Cellular-Based Notifications, May 2012

Following high winds on January 24, 2006, at least five people claimed to have seen or felt the superstructure of the Saylorville Reservoir Bridge in central Iowa moving both vertically and laterally. Since that time, the Iowa Department of Transportation (DOT) contracted with the Bridge Engineering Center at Iowa State University to design and install a monitoring system capable of providing notification of the occurrence of subsequent high winds. Although measures were put into place following the 2006 event at the Saylorville Reservoir Bridge, knowledge of the performance of this bridge during high wind events was incomplete. Therefore, the Saylorville Reservoir Bridge was outfitted with an information management system to investigate the structural performance of the structure and the potential for safety risks. In subsequent years, given the similarities between the Saylorville and Red Rock Reservoir bridges, a similar system was added to the Red Rock Reservoir Bridge southeast of Des Moines. The monitoring system developed and installed on these two bridges was designed to monitor the wind speed and direction at the bridge and, via a cellular modem, send a text message to Iowa DOT staff when wind speeds meet a predetermined threshold. The original intent was that, once the text message is received, the bridge entrances would be closed until wind speeds diminish to safe levels.

Prothèses totales de genoux. Analyse clinique et numérique des micromouvements de l'implant tibial [Total knee prosthesis. Clinical and numerical study of micromovements of the tibial implant].

INTRODUCTION: The importance of the micromovements in the mechanism of aseptic loosening is clinically difficult to evaluate. To complete the analysis of a series of total knee arthroplasties (TKA), we used a tridimensional numerical model to study the micromovements of the tibial implant. MATERIAL AND METHODS: Fifty one patients (with 57 cemented Porous Coated Anatomic TKAs) were reviewed (mean follow-up 4.5 year). Radiolucency at the tibial bone-cement interface was sought on the AP radiographs and divided in 7 areas. The distribution of the radiolucency was then correlated with the axis of the lower limb as measured on the orthoradiograms. The tridimensional numerical model is based on the finite element method. It allowed the measurement of the cemented prosthetic tibial implant's displacements and the micromovements generated at bone-ciment interface. A total load (2000 Newton) was applied at first vertically and asymetrically on the tibial plateau, thereby simulating an axial deviation of the lower limbs. The vector's posterior inclination then permitted the addition of a tangential component to the axial load. This type of effort is generated by complex biomechanical phenomena such as knee flexion. RESULTS: 81 per cent of the 57 knees had a radiolucent line of at least 1 mm, at one or more of the tibial cement-epiphysis jonctional areas. The distribution of these lucent lines showed that they came out more frequently at the periphery of the implant. The lucent lines appeared most often under the unloaded margin of the tibial plateau, when axial deviation of lower limbs was present. Numerical simulations showed that asymetrical loading on the tibial plateau induced a subsidence of the loaded margin (0-100 microns) and lifting off at the opposite border (0-70 microns). The postero-anterior tangential component induced an anterior displacement of the tibial implant (160-220 microns), and horizontal micromovements with non homogenous distribution at the bone-ciment interface (28-54 microns). DISCUSSION: Comparison of clinical and numerical results showed a relation between the development of radiolucent lines and the unloading of the tibial implant's margin. The deleterious effect of lower limbs' axial deviation is thereby proven. The irregular distribution of lucent lines under the tibial plateau was similar of the micromovements' repartition at the bone-cement interface when tangential forces were present. A causative relation between the two phenomenaes could not however be established. Numerical simulation is a truly useful method of study; it permits to calculate micromovements which are relative, non homogenous and of very low amplitude. However, comparative clinical studies remain as essential to ensure the credibility of results.

Learning wind fields with multiple kernels

This paper presents multiple kernel learning (MKL) regression as an exploratory spatial data analysis and modelling tool. The MKL approach is introduced as an extension of support vector regression, where MKL uses dedicated kernels to divide a given task into sub-problems and to treat them separately in an effective way. It provides better interpretability to non-linear robust kernel regression at the cost of a more complex numerical optimization. In particular, we investigate the use of MKL as a tool that allows us to avoid using ad-hoc topographic indices as covariables in statistical models in complex terrains. Instead, MKL learns these relationships from the data in a non-parametric fashion. A study on data simulated from real terrain features confirms the ability of MKL to enhance the interpretability of data-driven models and to aid feature selection without degrading predictive performances. Here we examine the stability of the MKL algorithm with respect to the number of training data samples and to the presence of noise. The results of a real case study are also presented, where MKL is able to exploit a large set of terrain features computed at multiple spatial scales, when predicting mean wind speed in an Alpine region.

Outcome of long-axis percutaneous sacroplasty for the treatment of sacral insufficiency fractures.

Our aim was to assess the clinical outcome of patients who were subjected to long-axis sacroplasty for the treatment of sacral insufficiency fractures. Nineteen patients with unilateral (n = 3) or bilateral (n = 16) sacral fractures were involved. Under local anaesthesia, each patient was subjected to CT-guided sacroplasty using the long-axis approach through a single entry point. An average of 6 ml of polymethylmethacrylate (PMMA) was delivered along the path of each sacral fracture. For each individual patient, the Visual Analogue pain Scale (VAS) before sacroplasty and at 1, 4, 24 and 48 weeks after the procedure was obtained. Furthermore, the use of analgesics (narcotic/non-narcotic) along with the evolution of post-interventional patient mobility before and after sacroplasty was also recorded. The mean pre-procedure VAS was 8 +/- 1.9 (range, 2 to 10). This rapidly and significantly (P < 0.001) declined in the first week after the procedure (mean 4 +/- 1.4; range, 1 to 7) followed by a gradual and significant (P < 0.001) decrease along the rest of the follow-up period at 4 weeks (mean 3 +/- 1.1; range, 1 to 5), 24 weeks (mean 2.2 +/- 1.1; range, 1 to 5) and 48 weeks (mean 1.6 +/- 1.1; range, 1 to 5). Eleven (58%) patients were under narcotic analgesia before sacroplasty, whereas 8 (42%) patients were using non-narcotics. Corresponding values after the procedure were 2/19 (10%; narcotic, one of them was on reserve) and 10/19 (53%; non-narcotic). The remaining 7 (37%) patients did not address post-procedure analgesic use. The evolution of post-interventional mobility was favourable in the study group as they revealed a significant improvement in their mobility point scale (P < 0.001). Long-axis percutaneous sacroplasty is a suitable, minimally invasive treatment option for patients who present with sacral insufficiency fractures. More studies with larger patient numbers are needed to explore any unrecognised limitations of this therapeutic approach.

Comparing the horizontal and vertical individualism and collectivism scale and the Auckland individualism and collectivism scale in two cultures: Switzerland and South Africa

This study investigated the psychometric properties of the Horizontal and Vertical Individualism and Collectivism Scale (HVIC) and the Auckland Individualism and Collectivism Scale (AICS). The sample consisted of 1,403 working individuals from Switzerland (N = 585) and from South Africa (N = 818). Principal component factor analyses indicated that a two-factor structure replicated well across the two countries for both scales. In addition, the HVIC four-factor structure replicated well across countries, whereas the responsibility dimension of individualism of the AICS replicated poorly. Confirmatory factor analyses provided satisfactory support to the original theoretical models for both the HVIC and the AICS. Equivalence measurement indices indicated that the cross-cultural replicability properties of both instruments are generally acceptable. However, canonical correlations and correlations between the HVIC and AICS dimensions confirm that these two instruments differ in their underlying meaning of the individualism and collectivism constructs, suggesting that these two instruments assess individualism and collectivism differently.

Multiple Kernel Learning of Environmental Data. Case study: Analysis and Mapping of Wind Fields

The paper presents the Multiple Kernel Learning (MKL) approach as a modelling and data exploratory tool and applies it to the problem of wind speed mapping. Support Vector Regression (SVR) is used to predict spatial variations of the mean wind speed from terrain features (slopes, terrain curvature, directional derivatives) generated at different spatial scales. Multiple Kernel Learning is applied to learn kernels for individual features and thematic feature subsets, both in the context of feature selection and optimal parameters determination. An empirical study on real-life data confirms the usefulness of MKL as a tool that enhances the interpretability of data-driven models.

Pseudo-two-girdles c-axis fabric patterns in a quartz-feldspar mylonite (Costabona granodiorite, Canigo massif)

An example of the relationship that exist between the preferred crystaliografic orientation of quartz grains and the attitude of the mylonite foliation of quartz-feldspar mylonites is described. These rocks are the result of the inhomogeneous deformation under low-grade metamorphic conditions of a late Hercynian granodiorite, intruded into the gneisses of the slopes of the Canig massif (Eastern Pyrenees). The Costabona mylonites have a quartz c-axis fabric in pseudo-twogirdles symmetrical with respect to the mylonite foliation and perpendicular to the shearband systems which produce an extensional crenulation of the mylonite foliation.

A novel Nrf2-miR-29-desmocollin-2 axis regulates desmosome function in keratinocytes.

The Nrf2 transcription factor controls the expression of genes involved in the antioxidant defense system. Here, we identified Nrf2 as a novel regulator of desmosomes in the epidermis through the regulation of microRNAs. On Nrf2 activation, expression of miR-29a and miR-29b increases in cultured human keratinocytes and in mouse epidermis. Chromatin immunoprecipitation identified the Mir29ab1 and Mir29b2c genes as direct Nrf2 targets in keratinocytes. While binding of Nrf2 to the Mir29ab1 gene activates expression of miR-29a and -b, the Mir29b2c gene is silenced by DNA methylation. We identified desmocollin-2 (Dsc2) as a major target of Nrf2-induced miR-29s. This is functionally important, since Nrf2 activation in keratinocytes of transgenic mice causes structural alterations of epidermal desmosomes. Furthermore, the overexpression of miR-29a/b or knockdown of Dsc2 impairs the formation of hyper-adhesive desmosomes in keratinocytes, whereas Dsc2 overexpression has the opposite effect. These results demonstrate that a novel Nrf2-miR-29-Dsc2 axis controls desmosome function and cutaneous homeostasis.

Inhibition of the Kit Ligand/c-Kit Axis Attenuates Metastasis in a Mouse Model Mimicking Local Breast Cancer Relapse after Radiotherapy.

PURPOSE: Local breast cancer relapse after breast-saving surgery and radiotherapy is associated with increased risk of distant metastasis formation. The mechanisms involved remain largely elusive. We used the well-characterized 4T1 syngeneic, orthotopic breast cancer model to identify novel mechanisms of postradiation metastasis. EXPERIMENTAL DESIGN: 4T1 cells were injected in 20 Gy preirradiated mammary tissue to mimic postradiation relapses, or in nonirradiated mammary tissue, as control, of immunocompetent BALB/c mice. Molecular, biochemical, cellular, histologic analyses, adoptive cell transfer, genetic, and pharmacologic interventions were carried out. RESULTS: Tumors growing in preirradiated mammary tissue had reduced angiogenesis and were more hypoxic, invasive, and metastatic to lung and lymph nodes compared with control tumors. Increased metastasis involved the mobilization of CD11b(+)c-Kit(+)Ly6G(high)Ly6C(low)(Gr1(+)) myeloid cells through the HIF1-dependent expression of Kit ligand (KitL) by hypoxic tumor cells. KitL-mobilized myeloid cells homed to primary tumors and premetastatic lungs, to give rise to CD11b(+)c-Kit(-) cells. Pharmacologic inhibition of HIF1, silencing of KitL expression in tumor cells, and inhibition of c-Kit with an anti-c-Kit-blocking antibody or with a tyrosine kinase inhibitor prevented the mobilization of CD11b(+)c-Kit(+) cells and attenuated metastasis. C-Kit inhibition was also effective in reducing mobilization of CD11b(+)c-Kit(+) cells and inhibiting lung metastasis after irradiation of established tumors. CONCLUSIONS: Our work defines KitL/c-Kit as a previously unidentified axis critically involved in promoting metastasis of 4T1 tumors growing in preirradiated mammary tissue. Pharmacologic inhibition of this axis represents a potential therapeutic strategy to prevent metastasis in breast cancer patients with local relapses after radiotherapy. Clin Cancer Res; 18(16); 4365-74. ©2012 AACR.