563 research outputs found

    Surgical repair of Achilles tendon rupture in dogs: A review of the literature, a case report and new perspectives

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    Achilles tendon rupture in the dog is a common traumatic lesion. An accurate evaluation of etiology, grade of the lesion with or without loss of tendon substance, and time elapsed from the trauma can guide the surgeon in choosing the best surgical technique. Moreover, the healing process after a tendon injury is usually difficult and uncertain because the prognosis is influenced by extent of trauma, time elapsed between the trauma and its treatment and low tendon vascularization. However, the rapid development of tissue engineering and regenerative medicine could soon result in the development of scaffolds with bioactive proteins that can direct the healing process toward complete tendon regeneration without fibrotic tissue development

    Evaluation of the Iatrogenic Sciatic Nerve Injury following Double Pelvic Osteotomy Performed with Piezoelectric Cutting Tool in Dogs

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    (1) Background: The double pelvic osteotomy (DPO) is a prophylactic surgical procedure associated with 0.4% incidence of sciatic nerve injury. The piezoelectric cutting tool is a surgical device able to involve only mineralized tissue avoiding neurovascular tissue and other soft tissue. This study aimed to evaluate the sciatic nerve injury observed in dogs underwent iliac osteotomy performed using the piezoelectric cutting tool. (2) Methods: Dogs underwent DPO performed with piezoelectric cutting tool were included. Neurological assessment was performed 6 and 24 h after surgery and then repeated 12 days, 4 and 8 weeks after surgery. Temporary and or permanent sciatic nerve injury were recorded. (3) Results: 84 DPOs performed in fifty dogs were included. No temporary/permanent neurological disease associated with iatrogenic damage of the sciatic nerve were observed. (4) Conclusions: The iliac osteotomy performed with piezoelectric cutting tool was not associated to iatrogenic sciatic nerve injury

    Non-pharmaceutical Interventions and the Infodemic on Twitter: Lessons Learned from Italy during the Covid-19 Pandemic

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    The COVID-19 pandemic changed expectations for information dissemination and use around the globe, challenging accepted models of communications, leadership, and social systems. We explore how social media discourse about COVID-19 in Italy was affected by the rapid spread of the virus, and how themes in postings changed with the adoption of social distancing measures and non-pharmaceutical interventions (NPI). We used topic modeling and social network analysis to highlight critical dimensions of conversations around COVID-19: 1) topics in social media postings about the Coronavirus; 2) the scope and reach of social networks; and 3) changes in social media content as the nation moved from partial to full social distancing. Twitter messages sent in Italy between February 11th and March 10th, 2020. 74,306 Tweets sent by institutions, news sources, elected officials, scientists and social media influencers. Messages were retweeted more than 1.2 million times globally. Non-parametric chi-square statistic with residual analysis to identify categories, chi-square test for linear trend, and Social Network Graphing. The first phase of the pandemic was dominated by social media influencers, followed by a focus on the economic consequences of the virus and placing blame on immigrants. As the crisis deepened, science-based themes began to predominate, with a focus on reducing the spread of the virus through physical distancing and business closures Our findings highlight the importance of messaging in social media in gaining the public’s trust and engagement during a pandemic. This requires credible scientific voices to garner public support for effective mitigation. Fighting the spread of an infectious disease goes hand in hand with stemming the dissemination of lies, bad science, and misdirection

    Lymphatic drainage mapping with indirect lymphography for canine mammary tumors

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    Mammary gland tumors are the most common canine neoplasms. They account for 25– 50% of all tumors diagnosed in bitches. Metastases and recurrences develop in about 35–70% of bitches following excision. The presence of regional lymph node metastases is a relevant factor affecting prognosis and treatment in cases of mammary gland tumors. The sentinel lymph node (SLN) is the first lymph node (or nodes) in the regional lymphatic basin that receives lymphatic flow from the primary neoplasm. The aim of this study is to investigate the SLN with indirect lymphography for a mammary tumor in dogs. The knowledge of the precise drainage pattern and SLN of the neoplastic mammary glands would provide clinically relevant information to the surgeon and to the oncologist, and it would be of high importance for the surgeon not only for performing the most adequate surgical excision but also for determining an accurate post-surgical prognosis

    Numerical modelling of Auriga's Wheel - a new ring galaxy

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    We model the formation of Auriga's Wheel - a recently discovered collisional ring galaxy. Auriga's Wheel has a number of interesting features including a bridge of stars linking the neighbouring elliptical to the ring galaxy, and evidence for components of expansion and rotation within the ring. Using N-body/SPH modelling, we study collisions between an elliptical galaxy and a late-type disk galaxy. A near direct collision, with a mildy inclined disk, is found to reasonably reproduce the general system morphology ~50 Myr following the collision. The collision must have a relatively low velocity (initially ~150 km s^{-1}) in order to form the observed bridge, and simultaneously match the galaxies separation. Our best-match model suggests the total disk galaxy is ~5 times more massive than the elliptical. We find that the velocity of expansion of the ring is sensitive to the mass of the elliptical, while insensitive to the encounter velocity. We evolve our simulation beyond the current epoch to study the future destiny of the galaxy pair. In our model, the nucleus moves further away from the plane of the ring in the direction of the stellar bridge. The nucleus eventually merges with the elliptical galaxy ~100 Myr after the present time. The ring continues to expand for ~200 Myr before collapsing back. The low initial relative velocity of the two galaxies will eventually result in a complete merger.Comment: Accepted to MNRAS, March 9th, 2012. 17 pages, 16 figures, no table

    Ram pressure drag - the effects of ram pressure on dark matter and stellar disk dynamics

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    We investigate the effects of ram pressure stripping on gas-rich disk galaxies in the cluster environment. Ram pressure stripping principally effects the atomic gas in disk galaxies, stripping away outer disk gas to a truncation radius. We demonstrate that the drag force exerted on truncated gas disks is passed to the stellar disk, and surrounding dark matter through their mutual gravity. Using a toy model of ram pressure stripping, we show that this can drag a stellar disk and dark matter cusp off centre within it's dark matter halo by several kiloparsecs. We present a simple analytical description of this process that predicts the drag force strength and its dependency on ram pressures and disk galaxy properties to first order. The motion of the disk can result in temporary deformation of the stellar disk. However we demonstrate that the key source of stellar disk heating is the removal of the gas potential from within the disk. This can result in disk thickening by approximately a factor of two in gas-rich disks.Comment: Accepted by MNRAS (Oct 2011) 17 pages, 11 figures, 1 tabl

    Ring Star Formation Rates in Barred and Nonbarred Galaxies

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    Nonbarred ringed galaxies are relatively normal galaxies showing bright rings of star formation in spite of lacking a strong bar. This morphology is interesting because it is generally accepted that a typical ring forms when material collects near a resonance, set up by the pattern speed of a bar or bar-like perturbation. Our goal in this paper is to examine whether the ring star formation properties are related to the non-axisymmetric gravity potential in general. For this purpose, we obtained H{\alpha} emission line images and calculated the line fluxes and star formation rates (SFRs) for 16 nonbarred SA galaxies and four weakly barred SAB galaxies with rings. For comparison, we combine our observations with a re-analysis of previously published data on five SA, seven SAB, and 15 SB galaxies with rings, three of which are duplicates from our sample. With these data, we examine what role a bar may play in the star formation process in rings. Compared to barred ringed galaxies, we find that the inner ring SFRs and H{\alpha}+[N ii] equivalent widths in nonbarred ringed galaxies show a similar range and trend with absolute blue magnitude, revised Hubble type, and other parameters. On the whole, the star formation properties of inner rings, excluding the distribution of H ii regions, are independent of the ring shapes and the bar strength in our small samples. We confirm that the deprojected axis ratios of inner rings correlate with maximum relative gravitational force Q_g; however, if we consider all rings, a better correlation is found when local bar forcing at the radius of the ring, Q_r, is used. Individual cases are described and other correlations are discussed. By studying the physical properties of these galaxies, we hope to gain a better understanding of their placement in the scheme of the Hubble sequence and how they formed rings without the driving force of a bar.Comment: 55 pages; 21 figures and 9 tables. Article has been accepted for publication in the Astronomical Journa
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