The nearby Galaxy structure toward the Vela Gum nebula

We report on $UBVI$ photometry and spectroscopy for MK classification purposes carried out in the fields of five open clusters projected against the Vela Gum in the Third Galactic Quadrant of the Galaxy. They are Ruprecht 20, Ruprecht 47, Ruprecht 60, NGC 2660 and NGC 2910. We could improve/confirm the parameters of these objects derived before. The spectroscopic parallax method has been applied to several stars located in the fields of four out of the five clusters to get their distances and reddenings. With this method we found two blue stars in the field of NGC 2910 at distances that make them likely members of Vela OB1 too. Also, projected against the fields of Ruprecht 20 and Ruprecht 47 we have detected other young stars favoring not only the existence of Puppis OB1 and OB2 but conforming a young stellar group at $\sim1$ kpc from the Sun and extending for more than 6 kpc outward the Galaxy. If this is the case, there is a thickening of the thin Galactic disk of more than 300 pc at just 2-3 kpc from the Sun. Ruprecht 60 and NGC 2660 are too old objects that have no physical relation with the associations under discussion. An astonishing result has been the detection in the background of Ruprecht 47 of a young star at the impressive distance of 9.5 kpc from the Sun that could be a member of the innermost part of the Outer Arm. Another far young star in the field of NGC 2660, at near 6.0 kpc, may become a probable member of the Perseus Arm or of the inner part of the Local Arm. The distribution of young clusters and stars onto the Third Galactic Quadrant agrees with recent findings concerning the extension of the Local Arm as revealed by parallaxes of regions of star formation. We show evidences too that added to previous ones found by our group explain the thickening of the thin disk as a combination of flare and warp.Comment: Accepted for publication in New Astronom

A defect-in-continuity in the canine femur: and in-vivo experimental model for the study of bone graft incorporation.

The in-vivo study of bone graft incorporation has traditionally used a segmental diaphyseal bone defect. This model reliably produces a nonunion, but is complicated by graft instability and altered limb loading stresses. The authors discuss the advantages of a defect-in-continuity canine femur model which produces a more consistent union with fewer mechanical complications despite the absence of fixation. This proposed model permits analysis of radiographic, histologic and biomechanical data which are more applicable to the usual clinical setting in which bone graft is required

Generating a magellanic star cluster catalog with ASteCA

An increasing number of software tools have been employed in the recent years for the automated or semi-automated processing of astronomical data. The main advantages of using these tools over a standard by-eye analysis include: speed (particularly for large databases), homogeneity, reproducibility, and precision. At the same time, they enable a statistically correct study of the uncertainties associated with the analysis, in contrast with manually set errors, or the still wide spread practice of simply not assigning errors. We present a catalog comprising 210 star clusters located in the Large and Small Magellanic Clouds, observed with Washington CT 1 photometry. Their fundamental parameters were estimated through an homogeneous,automatized and completely unassisted process, via the Automated Stellar Cluster Analysis package (ASteCA).Our results are compared with two types of studies on these clusters: one where the photometry is the same, andanother where the photometric system is different than that employed by ASteCA.Fil: Perren, Gabriel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Vázquez, R. A.. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentin

Quantitative analysis of bone reactions to relative motions at implant-bone interfaces

Connective soft tissues at the interface between implants and bone, such as in human joint replacements, can endanger the stability of the implant fixation. The potential of an implant to generate interface bone resorption and form soft tissue depends on many variables, including mechanical ones. These mechanical factors can be expressed in terms of relative motions between bone and implant at the interface or deformation of the interfacial material.\ud \ud The purpose of this investigation was to determine if interface debonding and subsequent relative interface motions can be responsible for interface degradation and soft tissue interposition as seen in experiments and clinical results. A finite element computer program was augmented with a mathematical description of interface debonding, dependent on interface stress criteria, and soft tissue interface interposition, dependent on relative interface motions. Three simplified models of orthopaedic implants were constructed: a cortical bone screw for fracture fixation plates, a femoral resurfacing prosthesis and a straight stem model, cemented in a bone. The predicted computer configurations were compared with clinical observations. The computer results showed how interface disruption and fibrous tissue interposition interrelate and possibly enhance each other, whereby a progressive development of the soft tissue layer can occur.\ud \ud Around the cortical bone screw, the predicted resorption patterns were relatively large directly under the screw head and showed a pivot point in the opposite cortex. The resurfacing cup model predicted some fibrous tissue formation under the medial and lateral cup rim, whereby the medial layer developed first because of higher initial interface stresses. The straight stem model predicted initial interface failure at the proximal parts. After proximal resorption and fibrous tissue interposition, the medial interface was completely disrupted and developed an interface layer. The distal and mid lateral side maintained within the strength criterion.\ud \ud Although the applied models were relatively simple, the results showed reasonable qualitative agreement with resorption patterns found in clinical studies concerning bone screws and the resurfacing cup. The hypothesis that interface debonding and subsequent relative (micro)motions could be responsible for bone resorption and fibrous tissue propagation is thereby sustained by the results

An analysis of the most distant catalogued open clusters -- Re-assessing fundamental parameters with Gaia EDR3 and ASteCA\texttt{ASteCA}

Several studies have been presented in the last few years applying some kind of automatic processing of data to estimate the fundamental parameters of open clusters. These parameters are later on employed in larger scale analyses, for example the structure of the Galaxy's spiral arms. The distance is one of the more straightforward parameters to estimate, yet enormous differences can still be found among published data. This is particularly true for open clusters located more than a few kpc away. We cross-matched several published catalogues and selected the twenty-five most distant open clusters ($>$9000 pc). We then performed a detailed analysis of their fundamental parameters, with emphasis on their distances, to determine the agreement between catalogues and our estimates.} Photometric and astrometric data from the Gaia EDR3 survey was employed. The data was processed with our own membership analysis code (pyUPMASK), and our package for automatic fundamental cluster's parameters estimation ($\texttt{ASteCA}$). We find differences in the estimated distances of up to several kpc between our results and those catalogued, even for the catalogues that show the best matches with $\texttt{ASteCA}$ values. Large differences are also found for the age estimates. As a by-product of the analysis we find that vd Bergh-Hagen 176 could be the open cluster with the largest heliocentric distance catalogued to date. Caution is thus strongly recommended when using catalogued parameters of open clusters to infer large-scale properties of the Galaxy, particularly for those located more than a few kpc away.Comment: Accepted for publication in A&

DAP12 (KARAP) amplifies inflammation and increases mortality from endotoxemia and septic peritonitis

DAP12 (KARAP) is a transmembrane signaling adaptor for a family of innate immunoreceptors that have been shown to activate granulocytes and monocytes/macrophages, amplifying production of inflammatory cytokines. Contrasting with these data, recent studies suggest that DAP12 signaling has an inhibitory role in the macrophage response to microbial products (Hamerman, J.A., N.K. Tchao, C.A. Lowell, and L.L. Lanier. 2005. Nat. Immunol. 6:579–586). To determine the in vivo role for DAP12 signaling in inflammation, we measured the response of wild-type (WT) and DAP12−/− mice to septic shock. We show that DAP12−/− mice have improved survival from both endotoxemia and cecal ligation and puncture–induced septic shock. As compared with WT mice, DAP12−/− mice have decreased plasma cytokine levels and a decreased acute phase response during sepsis, but no defect in the recruitment of cells or bacterial control. In cells isolated after sepsis and stimulated ex vivo, DAP12 signaling augments lipopolysaccharide-mediated cytokine production. These data demonstrate that, during sepsis, DAP12 signaling augments the response to microbial products, amplifying inflammation and contributing to mortality

Trends of mechanical consequences and modeling of a fibrous membrane around femoral hip prostheses

In the present study, the effects of a fibrous membrane between cement and bone in a femoral total hip replacement were investigated. The study involved the problem of modeling this fibrous membrane in finite-element analyses, and its global consequences for the load-transfer mechanism and its resulting stress patterns. A finite-element model was developed, suitable to describe nonlinear contact conditions in combination with nonlinear material properties of the fibrous membrane. The fibrous tissue layer was described as a highly compliant material with little resistance against tension and shear. The analysis showed that the load transfer mechanism from stem to bone changes drastically when such a membrane is present. These effects are predominantly caused by tensile loosening and slip at the interface, and are enhanced by the nonlinear membrane characteristics.\ud \ud Using parametric analysis, it was shown that these effects on the load-transfer mechanism cannot be described satisfactorily with linear elastic models.\ud \ud Most importantly, the fibrous tissue interposition causes excessive stress concentrations in bone and cement, and relatively high relative displacements between these materials

Glucagon-like peptide-1 (GLP-1) receptors are not overexpressed in pancreatic islets from patients with severe hyperinsulinaemic hypoglycaemia following gastric bypass

Aims/hypothesis: Glucagon-like peptide-1 (GLP-1) receptors are highly overexpressed in benign insulinomas, permitting in vivo tumour visualisation with GLP-1 receptor scanning. The present study sought to evaluate the GLP-1 receptor status in vitro in other pancreatic disorders leading to hyperinsulinaemic hypoglycaemia, specifically after gastric bypass surgery. Methods: Fresh frozen pancreatic tissue samples (n = 7) from six gastric bypass surgery patients suffering from hyperinsulinaemic hypoglycaemia were evaluated for GLP-1 receptor content using in vitro receptor autoradiography, and compared with normal pancreas and with pancreatic insulinoma tissues. Results: GLP-1 receptor analysis of the pancreatic tissues, which histopathologically were compatible with nesidioblastosis and originated from post-bypass hypoglycaemic patients, revealed a mean density value of GLP-1 receptors in the islets of 1,483 ± 183dpm/mg tissue. Pharmacological characterisation indicated the presence of specific GLP-1 receptors. The density of islet GLP-1 receptor in post-gastric bypass patients did not differ from that of normal pancreas (1,563 ± 104dpm/mg tissue, n = 10). Receptor density in pancreatic acini was low in post-bypass and control conditions. In contrast, benign insulinomas showed a high density of GLP-1 receptors, with a mean value of 8,302 ± 1,073dpm/mg tissue (n = 6). Conclusions/interpretation: In contrast to insulinoma, hyperinsulinaemic hypoglycaemia after gastric bypass surgery is not accompanied by overexpression of GLP-1 receptor in individual islets. Thus, patients with post-gastric bypass hyperinsulinaemic hypoglycaemia are not candidates for GLP-1 receptor imaging in vivo using radiolabelled exendin. These GLP-1 receptor data support the notion that the islet pathobiology of post-gastric bypass hypoglycaemia is distinctly different from that of benign insulinoma