108 research outputs found
Automated implantable cardiac defibrillator and biventricular thoratec assist device as bridge to transplantation in a patient with sarcoidosis
AbstractJ Thorac Cardiovasc Surg 2001;121:1198-
Trajectory Estimation for Particles Observed in the Vicinity of (101955) Bennu
We analyze the trajectories of 313 particles seen in the near‐Bennu environment between December 2018 and September 2019. Of these, 65% follow sub‐orbital trajectories, 20% undergo more than one orbital revolution around the asteroid, and 15% directly escape on hyperbolic trajectories. The median lifetime of these particles is ~6 h. The trajectories are sensitive to Bennu's gravitational field, which allows us to reliably estimate the spherical harmonic coefficients through degree 8 and to resolve nonuniform mass distribution through degree 3. The particles are perturbed by solar radiation pressure, enabling effective area‐to‐mass ratios to be estimated. By assuming that particles are oblate ellipsoids of revolution, and incorporating photometric measurements, we find a median axis ratio of 0.27 and diameters for equivalent‐volume spheres ranging from 0.22‐‐6.1 cm, with median 0.74 cm. Our size distribution agrees well with that predicted for fragmentation due to diurnal thermal cycling. Detailed models of known accelerations do not produce a match to the observed trajectories, so we also estimate empirical accelerations. These accelerations appear to be related to mismodeling of radiation pressure, but we cannot rule out contributions from mass loss. Most ejections take place at local solar times in the afternoon and evening (12:00‐‐24:00), although they occur at any time of day. We independently identify ten ejection events, some of which have previously been reported. We document a case where a particle ricocheted off the surface, revealing a coefficient of restitution 0.57±0.01 and demonstrating that some apparent ejections are not related to surface processes
Prevalencija infekcije Neisseriom gonorrhoeae ili Chlamydiom trachomatis kod akutnoga mukopurulentnog cervicitisa
The aim of this study was to determine the incidence of N. gonorrhoae (NG) and/or C. trachomatis (CT) in acute mucopurulent cervicitis (MPC). The study included 617 non-pregnant women with MPC, who had not been receiving any antimicrobial treatment. The average age of patients was 22.2 years. There were no statistically significant differences according to place of residence, education, and marital status. Samples for laboratory analysis were collected using a routine procedure; NG was identified using the cytochrome oxidase test and Gram staining. CT was isolated on McCoy cell culture and stained with Lugol solution. NG was isolated in three women (0.8 %) and CT in 58 women (9.4 %). Fifty-six of the CT-positive patients were nullipara and only two were unipara. All NG-positive patients were also nullipara. The mean number of sexual partners was 2.2 in all study subjects, 2.4 in CT-positive subjects, and 2.9 in NG-positive subjects. Vaginal discharge purity according to Schröder was significantly deteriorated in CT-positive patients (p=0.011). When asked about the use of contraceptives, as many as 32.7 % patients answered that they did not use any protection, 39 % women used the rhythm method and coitus interruptus, 20 % were taking oral contraceptives, 6.1 % used mechanical devices, and 1.9 % used chemical protection. Previous acute and chronic pelvic infl ammatory diseases correlated with MPC (p<0.01). Our statistical analysis suggests that chlamydial infection significantly reduces the purity of vaginal discharge, which is more pronounced in nulliparae. Pap smear was not specific enough to demonstrate chlamydial infection. In view of the MPC findings, the prevalence of CT and NG infection is low.Cilj istraživanja jest utvrditi koincidenciju N. gonorrhoae (NG) i/ili C. trachomatis (CT) u akutnim mukopurulentnim cervicitisima (MPC). Istraživanje je provedeno na populaciji 617 žena izvan trudnoće koje prethodno nisu uzimale antimikrobnu terapiju. NG i CT su izolirane iz obrisaka vrata maternice primjenom standardnih metoda. NG je transportirana na selektivnoj hranjivoj podlozi i identificirana citokrom-oksidaznim testom bojenjem po Gramu. CT je izolirana McCoyevom staničnom kulturom nakon bojenja Lugolovom otopinom. NG je izolirana u tri ispitanice (0,8 %), a CT u 58 ispitanica (9,4 %). Srednja dob bolesnica iznosila je 22,2 godine. Školovanje i bračno stanje nisu statistički značajno utjecali na rezultate istraživanja. Među bolesnicama s izoliranom CT prevladavaju nulipare, a u slučaju NG sve su pozitivne bolesnice također bile nulipare. Srednja vrijednost broja partnera za čitavu populaciju iznosi 2,2. Bolesnice s potvrđenom CT imale su prosječno 2,4, a one s potvrđenom NG 2,9 partnera. Vrijednost određivanja stupnja čistoće rodničkog iscjetka po Schroderu značajno je povišena u CT-pozitivnih bolesnica (p=0.011). Utvrđeno je da 32.7 % ispitanica uopće nije koristilo kontracepciju, dok je većina (39 %) rabila ritmičke metode i prekinuti snošaj. Preostale ispitanice uzimale su oralne kontraceptive (20 %), mehaničku zaštitu (6,1 %) ili lokalne kemijske kontraceptive (1,9 %). Također je dokazano da prethodna akutna i kronična zdjelična upalna bolest korelira s MPC-om (p<0.01). Zaključeno je da klamidijska infekcija statistički značajno korelira sa stupnjem čistoće rodničkog iscjetka, posebice u nulipara. Papanicolaouov razmaz nije specifičan u određivanju klamidijske infekcije. Rezultati istraživanja pokazuju da je učestalost klamidijske i gonokokne infekcije ipak relativno niska u odnosu na nalaz MPC-a
The clinical diagnosis of pelvic inflammatory disease – reuse of electronic medical record data from 189 patients visiting a Swedish university hospital emergency department
BACKGROUND: The pelvic inflammatory disease (PID) diagnosis is mostly based on clinical findings. However, few studies have examined the clinical basis for the diagnostics of PID, which was the aim of this study. METHODS: A retrospective study was performed of 189 out-patients diagnosed as having PID at the obstetric and gynecological emergency department of a Swedish university hospital. Data on symptoms, signs, pelvic examination and laboratory tests were extracted from the electronic medical records in comparison with the diagnostic criteria of the PID Guideline of the US Center of Disease Control from 2002 (CDC 2002 Guidelines). RESULTS: Eight symptoms in varying combinations were associated with the PID diagnosis. Most of them are mentioned in the CDC 2002 Guidelines. Detected rates of C. Trachomatis (CT) and N. Gonorrhoeae (NG) were 5% and 0%, respectively, among the tested patients (CT = 52% and NG = 12%). The C-reactive protein was normal in the majority of tested patients. CONCLUSION: The clinical basis for the diagnostics of PID was largely in accordance with the criteria in the CDC 2002 Guidelines. The limited number of CT tests performed is somewhat disappointing, considering the fact that effective disease prevention includes widespread CT screening. Further studies in different settings are needed in order to analyze how the testing rate for CT can be improved in clinical praxis
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Variations in color and reflectance on the surface of asteroid (101955) Bennu
Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. We present multispectral images (0.44 to 0.89 microns) of near-Earth asteroid (101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their reflectance and texture. Space weathering of Bennu surface materials does not simply progress from red to blue (or vice versa). Instead, freshly exposed, redder surfaces initially brighten in the near-ultraviolet (become bluer at shorter wavelengths), then brighten in the visible to near-infrared, leading to Bennu’s moderately blue average color. Craters indicate that the timescale of these color changes is ~105 years. We attribute the reflectance and color variation to a combination of primordial heterogeneity and varying exposure ages
Episodes of particle ejection from the surface of the active asteroid (101955) Bennu
Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances of particle ejection from the surface of (101955) Bennu, demonstrating that it is an active asteroid. The ejection events were imaged by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft. For the three largest events, we estimated the ejected particle velocities and sizes, event times, source regions, and energies. We also determined the trajectories and photometric properties of several gravitationally bound particles that orbited temporarily in the Bennu environment. We consider multiple hypotheses for the mechanisms that lead to particle ejection for the largest events, including rotational disruption, electrostatic lofting, ice sublimation, phyllosilicate dehydration, meteroid impacts, thermal stress fracturing, and secondary impacts
Extensive Genetic Diversity, Unique Population Structure and Evidence of Genetic Exchange in the Sexually Transmitted Parasite Trichomonas vaginalis
The human parasite Trichomonas vaginalis causes trichomoniasis, the world's most common non-viral sexually transmitted infection. Research on T. vaginalis genetic diversity has been limited by a lack of appropriate genotyping tools. To address this problem, we recently published a panel of T. vaginalis-specific genetic markers; here we use these markers to genotype isolates collected from ten regions around the globe. We detect high levels of genetic diversity, infer a two-type population structure, identify clinically relevant differences between the two types, and uncover evidence of genetic exchange in what was believed to be a clonal organism. Together, these results greatly improve our understanding of the population genetics of T. vaginalis and provide insights into the possibility of genetic exchange in the parasite, with implications for the epidemiology and control of the disease. By taking into account the existence of different types and their unique characteristics, we can improve understanding of the wide range of symptoms that patients manifest and better implement appropriate drug treatment. In addition, by recognizing the possibility of genetic exchange, we are more equipped to address the growing concern of drug resistance and the mechanisms by which it may spread within parasite populations
Regulation of Budding Yeast Mating-Type Switching Donor Preference by the FHA Domain of Fkh1
During Saccharomyces cerevisiae mating-type switching, an HO endonuclease-induced double-strand break (DSB) at MAT is repaired by recombining with one of two donors, HMLα or HMRa, located at opposite ends of chromosome III. MATa cells preferentially recombine with HMLα; this decision depends on the Recombination Enhancer (RE), located about 17 kb to the right of HML. In MATα cells, HML is rarely used and RE is bound by the MATα2-Mcm1 corepressor, which prevents the binding of other proteins to RE. In contrast, in MATa cells, RE is bound by multiple copies of Fkh1 and a single copy of Swi4/Swi6. We report here that, when RE is replaced with four LexA operators in MATa cells, 95% of cells use HMR for repair, but expression of a LexA-Fkh1 fusion protein strongly increases HML usage. A LexA-Fkh1 truncation, containing only Fkh1's phosphothreonine-binding FHA domain, restores HML usage to 90%. A LexA-FHA-R80A mutant lacking phosphothreonine binding fails to increase HML usage. The LexA-FHA fusion protein associates with chromatin in a 10-kb interval surrounding the HO cleavage site at MAT, but only after DSB induction. This association occurs even in a donorless strain lacking HML. We propose that the FHA domain of Fkh1 regulates donor preference by physically interacting with phosphorylated threonine residues created on proteins bound near the DSB, thus positioning HML close to the DSB at MAT. Donor preference is independent of Mec1/ATR and Tel1/ATM checkpoint protein kinases but partially depends on casein kinase II. RE stimulates the strand invasion step of interchromosomal recombination even for non-MAT sequences. We also find that when RE binds to the region near the DSB at MATa then Mec1 and Tel1 checkpoint kinases are not only able to phosphorylate histone H2A (γ-H2AX) around the DSB but can also promote γ-H2AX spreading around the RE region
Rad51 Polymerization Reveals a New Chromatin Remodeling Mechanism
Rad51 protein is a well known protagonist of homologous recombination in eukaryotic cells. Rad51 polymerization on single-stranded DNA and its role in presynaptic filament formation have been extensively documented. Rad51 polymerizes also on double-stranded DNA but the significance of this filament formation remains unclear. We explored the behavior of Saccharomyces cerevisiae Rad51 on dsDNA and the influence of nucleosomes on Rad51 polymerization mechanism to investigate its putative role in chromatin accessibility to recombination machinery. We combined biochemical approaches, transmission electron microscopy (TEM) and atomic force microscopy (AFM) for analysis of the effects of the Rad51 filament on chromatinized templates. Quantitative analyses clearly demonstrated the occurrence of chromatin remodeling during nucleoprotein filament formation. During Rad51 polymerization, recombinase proteins moved all the nucleosomal arrays in front of the progressing filament. This polymerization process had a powerful remodeling effect, as Rad51 destabilized the nucleosomes along considerable stretches of DNA. Similar behavior was observed with RecA. Thus, recombinase polymerization is a powerful mechanism of chromatin remodeling. These remarkable features open up new possibilities for understanding DNA recombination and reveal new types of ATP-dependent chromatin dynamics
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