949 research outputs found

    Bacteria isolated from Bengal cat (Felis catus × Prionailurus bengalensis) anal sac secretions produce volatile compounds potentially associated with animal signaling.

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    In social animals, scent secretions and marking behaviors play critical roles in communication, including intraspecific signals, such as identifying individuals and group membership, as well as interspecific signaling. Anal sacs are an important odor producing organ found across the carnivorans (species in the mammalian Order Carnivora). Secretions from the anal sac may be used as chemical signals by animals for behaviors ranging from defense to species recognition to signaling reproductive status. In addition, a recent study suggests that domestic cats utilize short-chain free fatty acids in anal sac secretions for individual recognition. The fermentation hypothesis is the idea that symbiotic microorganisms living in association with animals contribute to odor profiles used in chemical communication and that variation in these chemical signals reflects variation in the microbial community. Here we examine the fermentation hypothesis by characterizing volatile organic compounds (VOC) and bacteria isolated from anal sac secretions collected from a male Bengal cat (Felis catus × Prionailurus bengalensis), a cross between the domestic cat and the leopard cat. Both left and right anal sacs of a male Bengal cat were manually expressed (emptied) and collected. Half of the material was used to culture bacteria or to extract bacterial DNA and the other half was used for VOC analysis. DNA was extracted from the anal sac secretions and used for a 16S rRNA gene PCR amplification and sequencing based characterization of the microbial community. Additionally, some of the material was plated out in order to isolate bacterial colonies. Three taxa (Bacteroides fragilis, Tessaracoccus, and Finegoldia magna) were relatively abundant in the 16S rRNA gene sequence data and also isolated by culturing. Using Solid Phase Microextraction (SPME) gas chromatography-mass spectrometry (GC-MS), we tentatively identified 52 compounds from the Bengal cat anal sac secretions and 67 compounds from cultures of the three bacterial isolates chosen for further analysis. Among 67 compounds tentatively identified from bacterial isolates, 51 were also found in the anal sac secretion. We show that the bacterial community in the anal sac consists primarily of only a few abundant taxa and that isolates of these taxa produce numerous volatiles that are found in the combined anal sac volatile profile. Several of these volatiles are found in anal sac secretions from other carnivorans, and are also associated with known bacterial biosynthesis pathways. This is consistent with the fermentation hypothesis and the possibility that the anal sac is maintained at least in part to house bacteria that produce volatiles for the host

    Expression of Hex mRNA in early murine postimplantation embryo development

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    AbstractThe onset of Hex expression and its role in early murine development was analyzed using in situ hybridization. Hex mRNA was first detected in the chorion of the ectoplacental cavity and weakly at the visceral endoderm of the future yolk sac at embryonic age (E) 7.5. Expression in embryonic tissues was detected exclusively in the hepatic anlage and thyroid primordium at E 9.5. At E 12.5 and E 15.5, Hex expression persisted in the fetal liver and thyroid, and was also detected in the fetal lung. These results suggest that Hex has its role in differentiation and/or organogenesis of several embryonic tissues

    Direct Visualization of 3-Dimensional Force and Energy Map of a Single Molecular Switch

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    Mechanical properties of molecules adsorbed on materials surfaces are increasingly vital for the applications of molecular thin films. Here, we conduct a fundamental research to induce conformational change mechanically on a single molecule and quantify the driving force needed for such molecular shape switch via a low temperature (~ 5K) Scanning Tunneling Microscope (STM) and Qplus Atomic Force Microscope (Q+AFM). Our measurement maps a three-dimensional landscape for mechanical potential and force at single molecule level with high spatial resolution in all three dimensions of a few angstrom (10-10 m). Molecule TBrPP-Co (a cobalt porphyrin) deposited on an atomically clean gold substrate typically has two of its pentagon rings tilted upward and the other two downward. An atomically sharp tip of the STM/Q+AFM, which vibrates with a high frequency (~ 30kHz), is employed to scan the molecule at different heights with 0.1Å increment and meanwhile record tip-molecule interaction strength in the form of tip frequency change. When tip approaches to the threshold distance to the molecule, mechanical force become large enough and cause pentagon rings flip their direction. Due to the sensitive nature of tip-molecule interaction, the rings flipping can be directly visualized by STM, as rings tilting upward exhibit two bright protrusions in contrast to rings downward in image. By processing frequency change, we obtain a three-dimensional mechanical potential and force map for a single molecule with the resolution of angstrom level in all three dimensions. Our preliminary results indicate that an energy barrier of ~400meV needs to be overcome for rings flipping of TBrPP-Co.https://digitalcommons.odu.edu/gradposters2021_sciences/1015/thumbnail.jp

    NuSTAR observations of water megamaser AGN

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    Aims. We study the connection between the masing disk and obscuring torus in Seyfert 2 galaxies. Methods. We present a uniform X-ray spectral analysis of the high energy properties of 14 nearby megamaser active galactic nuclei observed by NuSTAR. We use a simple analytical model to localize the maser disk and understand its connection with the torus by combining NuSTAR spectral parameters with the available physical quantities from VLBI mapping. Results. Most of the sources that we analyzed are heavily obscured, showing a column density in excess of ~10^(23) cm^(-2); in particular, 79% are Compton-thick (N_H > 1.5 × 10^(24) cm^(-2)). When using column densities measured by NuSTAR with the assumption that the torus is the extension of the maser disk, and further assuming a reasonable density profile, we can predict the torus dimensions. They are found to be consistent with mid-IR interferometry parsec-scale observations of Circinus and NGC 1068. In this picture, the maser disk is intimately connected to the inner part of the torus. It is probably made of a large number of molecular clouds that connect the torus and the outer part of the accretion disk, giving rise to a thin disk rotating in most cases in Keplerian or sub-Keplerian motion. This toy model explains the established close connection between water megamaser emission and nuclear obscuration as a geometric effect

    Isolated congenital tracheal stenosis in a preterm newborn

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    Severe tracheal stenosis, resulting in functional atresia of the trachea is a rare congenital malformation with an estimated occurrence of two in 100,000 newborns. If no esophagotracheal fistula is present to allow for spontaneous breathing, this condition is usually fatal. We report on a male infant born at 32 weeks of gestation. The patient presented with respiratory distress immediately after delivery due to severe congenital tracheal stenosis resulting in functional atresia of the trachea. Endotracheal intubation failed and even emergency tracheotomy did not allow ventilation of the patient lungs. The patient finally succumbed to prolonged hypoxia due to functional tracheal atresia. The etiology of tracheal atresia and tracheal stenosis is still unclear, but both conditions are frequently combined with other anomalies of the VACTERL (vertebral anomalies, anal atresia, cardiovascular anomalies, tracheoesophageal fistula, esophageal atresia, renal/radial anomalies and limb defects) and TACRD (tracheal agenesis, cardiac, renal and duodenal malformations) association. Conclusion Successful treatment of severe congenital tracheal stenosis and tracheal atresia depends on either prenatal diagnosis or recognition of this condition immediately after birth to perform tracheotomy without delay. Nevertheless, despite any efforts, the therapeutical results of severe tracheal stenosis and tracheal atresia are still unsatisfactory

    Persistent Diffusion-Restricted Lesions in Bevacizumab-Treated Malignant Gliomas Are Associated with Improved Survival Compared with Matched Controls

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    Background and purposeA subset of patients with malignant glioma develops conspicuous lesions characterized by persistent restricted diffusion during treatment with bevacizumab. The purpose of the current study was to characterize the evolution of these lesions and to determine their relationship to patient outcome.Materials and methodsTwenty patients with malignant glioma with persistent restricted-diffusion lesions undergoing treatment with bevacizumab were included in the current study. Mean ADC and the volume of restricted diffusion were computed for each patient during serial follow-up. Differences in TTP, TTS, and OS were compared between patients with restricted diffusion and matched controls by using Kaplan-Meier analysis with the logrank test and Cox hazard models.ResultsMean ADC values were generally stable with time (mean, 5.2 ± 12.6% change from baseline). The volume of restricted diffusion increased a median of 23% from baseline by 6 months. Patients with restricted-diffusion lesions had significantly greater TTP (logrank, P = .013), TTS (logrank, P = .008), and OS (logrank, P = .010) than matched controls. When available, advanced physiologic imaging of restricted-diffusion lesions showed hypovascularity on perfusion MR imaging and decreased amino acid uptake on (18)F-FDOPA PET scans. Atypical gelatinous necrotic tissue was confirmed in the area of restricted diffusion in 1 patient.ConclusionsRestricted-diffusion lesions in malignant gliomas treated with bevacizumab are generally stable with time and are associated with improved outcomes. These results combined with physiologic imaging and histopathologic data suggest that these lesions are not consistent with aggressive tumor

    Community-based assessment of human rights in a complex humanitarian emergency: the Emergency Assistance Teams-Burma and Cyclone Nargis

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    <p>Abstract</p> <p>Introduction</p> <p>Cyclone Nargis hit Burma on May 2, 2008, killing over 138,000 and affecting at least 2.4 million people. The Burmese military junta, the State Peace and Development Council (SPDC), initially blocked international aid to storm victims, forcing community-based organizations such as the Emergency Assistance Teams-Burma (EAT) to fill the void, helping with cyclone relief and long-term reconstruction. Recognizing the need for independent monitoring of the human rights situation in cyclone-affected areas, particularly given censorship over storm relief coverage, EAT initiated such documentation efforts.</p> <p>Methods</p> <p>A human rights investigation was conducted to document selected human rights abuses that had initially been reported to volunteers providing relief services in cyclone affected areas. Using participatory research methods and qualitative, semi-structured interviews, EAT volunteers collected 103 testimonies from August 2008 to June 2009; 42 from relief workers and 61 from storm survivors.</p> <p>Results</p> <p>One year after the storm, basic necessities such as food, potable water, and shelter remained insufficient for many, a situation exacerbated by lack of support to help rebuild livelihoods and worsening household debt. This precluded many survivors from being able to access healthcare services, which were inadequate even before Cyclone Nargis. Aid efforts continued to be met with government restrictions and harassment, and relief workers continued to face threats and fear of arrest. Abuses, including land confiscation and misappropriation of aid, were reported during reconstruction, and tight government control over communication and information exchange continued.</p> <p>Conclusions</p> <p>Basic needs of many cyclone survivors in the Irrawaddy Delta remained unmet over a year following Cyclone Nargis. Official impediments to delivery of aid to storm survivors continued, including human rights abrogations experienced by civilians during reconstruction efforts. Such issues remain unaddressed in official assessments conducted in partnership with the SPDC. Private, community-based relief organizations like EAT are well positioned and able to independently assess human rights conditions in response to complex humanitarian emergencies such as Cyclone Nargis; efforts of this nature must be encouraged, particularly in settings where human rights abuses have been documented and censorship is widespread.</p

    Search for Pair Production of Scalar Top Quarks Decaying to a tau Lepton and a b Quark in ppbar Collisions at sqrt{s}=1.96 TeV

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    We search for pair production of supersymmetric top quarks (~t_1), followed by R-parity violating decay ~t_1 -> tau b with a branching ratio beta, using 322 pb^-1 of ppbar collisions at sqrt{s}=1.96 TeV collected by the CDF II detector at Fermilab. Two candidate events pass our final selection criteria, consistent with the standard model expectation. We set upper limits on the cross section sigma(~t_1 ~tbar_1)*beta^2 as a function of the stop mass m(~t_1). Assuming beta=1, we set a 95% confidence level limit m(~t_1)>153 GeV/c^2. The limits are also applicable to the case of a third generation scalar leptoquark (LQ_3) decaying LQ_3 -> tau b.Comment: 7 pages, 2 eps figure

    Measurement of the Lifetime Difference Between B_s Mass Eigenstates

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    We present measurements of the lifetimes and polarization amplitudes for B_s --> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and light (L) mass eigenstates in the B_s system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07 +{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s and average Gamma_s, of the decay rates of the two eigenstates, the results are DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47 +{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters on 16 March 2005; revisions are for length and typesetting only, no changes in results or conclusion
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