294 research outputs found

    Idiopathic radiographic apical root resorption in wind instrument players

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    Root resorption of the permanent teeth involves an elaborate interaction among inflammatory cells resulting in loss of dental hard tissues. This report describes three clinical cases where idiopathic root resorption occurred in wind instrument playing patients. These patients produce adequate non-orthodontic forces, while playing their instruments, to expose their teeth to root resorbing force. Careful clinical monitoring of patients' teeth should be undertaken, as the additive effects of orthodontic treatment and musical habits are unknown

    The California-Kepler survey. X. The radius gap as a function of stellar mass, metallicity, and age

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    In 2017, the California-Kepler Survey (CKS) published its first data release (DR1) of high-resolution optical spectra of 1305 planet hosts. Refined CKS planet radii revealed that small planets are bifurcated into two distinct populations, super-Earths (smaller than 1.5 R⊕) and sub-Neptunes (between 2.0 and 4.0 R⊕), with few planets in between (the "radius gap"). Several theoretical models of the radius gap predict variation with stellar mass, but testing these predictions is challenging with CKS DR1 due to its limited M⋆ range of 0.8–1.4 M⊙. Here we present CKS DR2 with 411 additional spectra and derived properties focusing on stars of 0.5–0.8 M⊙. We found that the radius gap follows Rp ∝ Pm with m = −0.10 ± 0.03, consistent with predictions of X-ray and ultraviolet- and core-powered mass-loss mechanisms. We found no evidence that m varies with M⋆. We observed a correlation between the average sub-Neptune size and M⋆. Over 0.5–1.4 M⊙, the average sub-Neptune grows from 2.1 to 2.6 R⊕, following RpMα{R}_{p}\propto {M}_{\star }^{\alpha } with α = 0.25 ± 0.03. In contrast, there is no detectable change for super-Earths. These M⋆–Rp trends suggest that protoplanetary disks can efficiently produce cores up to a threshold mass of Mc, which grows linearly with stellar mass according to Mc ≈ 10 M⊕(M⋆/M⊙). There is no significant correlation between sub-Neptune size and stellar metallicity (over −0.5 to +0.5 dex), suggesting a weak relationship between planet envelope opacity and stellar metallicity. Finally, there is no significant variation in sub-Neptune size with stellar age (over 1–10 Gyr), which suggests that the majority of envelope contraction concludes after ∼1 Gyr

    Exploring new physics frontiers through numerical relativity

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    The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology

    Mantle cell lymphoma of the gastrointestinal tract presenting with multiple intussusceptions – case report and review of literature

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    <p>Abstract</p> <p>Background</p> <p>Mantle cell lymphoma (MCL) is an aggressive type of B-cell non-Hodgkin's lymphoma that originates from small to medium sized lymphocytes located in the mantle zone of the lymph node. Extra nodal involvement is present in the majority of cases, with a peculiar tendency to invade the gastro-intestinal tract in the form of multiple lymphomatous polyposis. MCL can be accurately diagnosed with the use of the highly specific marker Cyclin D1. Few cases of mantle cell lymphoma presenting with intussuception have been reported. Here we present a rare case of multiple intussusceptions caused by mantle cell lymphoma and review the literature of this disease.</p> <p>Case presentation</p> <p>A 68-year-old male presented with pain, tenderness in the right lower abdomen, associated with nausea and non-bilious vomiting. CT scan of abdomen revealed ileo-colic intussusception. Laparoscopy confirmed multiple intussusceptions involving ileo-colic and ileo-ileal segments of gastrointestinal tract. A laparoscopically assisted right hemicolectomy and extended ileal resection was performed. Postoperative recovery was uneventful. The histology and immuno-histochemistry of the excised small and large bowel revealed mantle cell lymphoma with multiple lymphomatous polyposis and positivity to Cyclin D1 marker. The patient was successfully treated with Rituximab-CHOP chemotherapy and remains in complete remission at one-year follow-up.</p> <p>Conclusion</p> <p>This is a rare case of intestinal lymphomatous polyposis due to mantle cell lymphoma presenting with multiple small bowel intussusceptions. Our case highlights laparoscopic-assisted bowel resection as a potential and feasible option in the multi-disciplinary treatment of mantle cell lymphoma.</p

    Factors associated with preservation of facial nerve function after surgical resection of vestibular schwannoma

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    Avoidance of facial nerve palsy is one of the major goals of vestibular schwannoma (VS) microsurgery. In this study, we examined the significance of previously implicated prognostic factors (age, tumor size, the extent of resection and the surgical approach) on post-operative facial nerve function. We selected all VS patients from prospectively collected database (1984–2009) who underwent microsurgical resection as their initial treatment for histopathologically confirmed VS. The effect of variables such as surgical approach, tumor size, patient age and extent of resection on rates facial nerve dysfunction after surgery, were analyzed using multivariate logistic regression. Patients with preoperative facial nerve dysfunction (House-Brackman [HB] score 3 or higher) were excluded, and HB grade of 1 or 2 at the last follow-up visit was defined as “facial nerve preservation.” A total of 624 VS patients were included in this study. Multivariate logistic regression analysis found that only pre-operative tumor size significantly predicted poorer facial nerve outcome for patients followed-up for ≥6 and ≥12 months (OR 1.27, 95% CI 1.09–1.49, p < 0.01; OR 1.35, 95% CI 1.10–1.67, P < 0.01, respectively). We found no significant relationship between facial nerve function and age, extent of resection, surgical approach, or tumor size (when extent of resection and surgical approach were included in the regression analysis). Because facial nerve palsy is a debilitating and psychologically devastating condition for the patient, we suggest altering surgical aggressiveness in patients with unfavorable tumor anatomy, particularly in cases with large tumors where overaggressive resection might subject the patient to unwarranted risk. Residual disease can be followed and controlled with radiosurgery if interval growth is noted

    Toi-1235 b: A keystone super-earth for testing radius valley emergence models around early m dwarfs

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    Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally-driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/non-rocky transition in period-radius space. Here we present the confirmation of TOI-1235 b (P=3.44P=3.44 days, rp=1.7380.076+0.087r_p=1.738^{+0.087}_{-0.076} R_{\oplus}), a planet whose size and period are intermediate between the competing model predictions, thus making the system an important test case for emergence models of the rocky/non-rocky transition around early M dwarfs (Rs=0.630±0.015R_s=0.630\pm 0.015 R_{\odot}, Ms=0.640±0.016M_s=0.640\pm 0.016 M_{\odot}). We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high-resolution imaging, and a set of 38 precise radial-velocities from HARPS-N and HIRES. We measure a planet mass of 6.910.85+0.756.91^{+0.75}_{-0.85} M_{\oplus} which implies an iron core mass fraction of 2012+1520^{+15}_{-12}% in the absence of a gaseous envelope. The bulk composition of TOI-1235 b is therefore consistent with being Earth-like and we constrain a H/He envelope mass fraction to be <0.5<0.5% at 90% confidence. Our results are consistent with model predictions from thermally-driven atmospheric mass loss but not with gas-poor formation, which suggests that the former class of processes remain efficient at sculpting close-in planets around early M dwarfs. Our RV analysis also reveals a strong periodicity close to the first harmonic of the photometrically-determined stellar rotation period that we treat as stellar activity, despite other lines of evidence favoring a planetary origin (P=21.80.8+0.9P=21.8^{+0.9}_{-0.8} days, mpsini=13.05.3+3.8m_p\sin{i}=13.0^{+3.8}_{-5.3} M_{\oplus}) that cannot be firmly ruled out by our data

    Mass constraints of the WASP-47 planetary system from radial velocities

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    We report precise radial velocity (RV) measurements of WASP-47, a G star that hosts three transiting planets in close proximity (a hot Jupiter, a super-Earth, and a Neptune-sized planet) and a non-transiting planet at 1.4 au. Through a joint analysis of previously published RVs and our own Keck-HIRES RVs, we significantly improve the planet mass and bulk density measurements. For the super-Earth WASP-47e (P = 0.79 days), we measure a mass of 9.11 ± 1.17 Ṁ, and a bulk density of 7.63 ± 1.90 g cm-3, consistent with a rocky composition. For the hot Jupiter WASP-47b (P = 4.2 days), we measure a mass of 356 ± 12Ṁ(1.12 ± 0.04 MJup) and constrain its eccentricity to at 3σ confidence. For the Neptune-size planet WASP-47d (P = 9.0 days), we measure a mass of 12.75 ± 50.0 and a bulk density of g cm-3, suggesting that it has a thick H/He envelope. For the outer non-transiting planet, we measure a minimum mass of 411 ±18Ṁ(1.29 ± 0.06 MJup), an orbital period of days, and an orbital eccentricity of . Our new measurements are consistent with but two to four times more precise than previous mass measurements

    Simulation of Postsynaptic Glutamate Receptors Reveals Critical Features of Glutamatergic Transmission

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    Activation of several subtypes of glutamate receptors contributes to changes in postsynaptic calcium concentration at hippocampal synapses, resulting in various types of changes in synaptic strength. Thus, while activation of NMDA receptors has been shown to be critical for long-term potentiation (LTP) and long term depression (LTD) of synaptic transmission, activation of metabotropic glutamate receptors (mGluRs) has been linked to either LTP or LTD. While it is generally admitted that dynamic changes in postsynaptic calcium concentration represent the critical elements to determine the direction and amplitude of the changes in synaptic strength, it has been difficult to quantitatively estimate the relative contribution of the different types of glutamate receptors to these changes under different experimental conditions. Here we present a detailed model of a postsynaptic glutamatergic synapse that incorporates ionotropic and mGluR type I receptors, and we use this model to determine the role of the different receptors to the dynamics of postsynaptic calcium with different patterns of presynaptic activation. Our modeling framework includes glutamate vesicular release and diffusion in the cleft and a glutamate transporter that modulates extracellular glutamate concentration. Our results indicate that the contribution of mGluRs to changes in postsynaptic calcium concentration is minimal under basal stimulation conditions and becomes apparent only at high frequency of stimulation. Furthermore, the location of mGluRs in the postsynaptic membrane is also a critical factor, as activation of distant receptors contributes significantly less to calcium dynamics than more centrally located ones. These results confirm the important role of glutamate transporters and of the localization of mGluRs in postsynaptic sites in their signaling properties, and further strengthen the notion that mGluR activation significantly contributes to postsynaptic calcium dynamics only following high-frequency stimulation. They also provide a new tool to analyze the interactions between metabotropic and ionotropic glutamate receptors

    Heat-shock proteins in infection-mediated inflammation-induced tumorigenesis

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    Inflammation is a necessary albeit insufficient component of tumorigenesis in some cancers. Infectious agents directly implicated in tumorigenesis have been shown to induce inflammation. This process involves both the innate and adaptive components of the immune system which contribute to tumor angiogenesis, tumor tolerance and metastatic properties of neoplasms. Recently, heat-shock proteins have been identified as mediators of this inflammatory process and thus may provide a link between infection-mediated inflammation and subsequent cancer development. In this review, the role of heat-shock proteins in infection-induced inflammation and carcinogenesis will be discussed

    Following the genes: a framework for animal modeling of psychiatric disorders

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    The number of individual cases of psychiatric disorders that can be ascribed to identified, rare, single mutations is increasing with great rapidity. Such mutations can be recapitulated in mice to generate animal models with direct etiological validity. Defining the underlying pathogenic mechanisms will require an experimental and theoretical framework to make the links from mutation to altered behavior in an animal or psychopathology in a human. Here, we discuss key elements of such a framework, including cell type-based phenotyping, developmental trajectories, linking circuit properties at micro and macro scales and definition of neurobiological phenotypes that are directly translatable to humans
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