267 research outputs found

    Determination of Deuteron Beam Polarizations at COSY

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    The vector and tensor polarizations of a deuteron beam have been measured using elastic deuteron-carbon scattering at 75.6 MeV and deuteron-proton scattering at 270 MeV. After acceleration to 1170 MeV inside the COSY ring, the polarizations of the deuterons were checked by studying a variety of nuclear reactions using a cluster target at the ANKE magnet spectrometer placed at an internal target position of the storage ring. All these measurements were consistent with the absence of depolarization during acceleration and provide a number of secondary standards that can be used in subsequent experiments at the facility.Comment: 12 pages, 13 figure

    Sequences outside recognition sets are not neutral for tRNA aminoacylation. Evidence for nonpermissive combinations of nucleotides in the acceptor stem of yeast tRNAPhe.

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    Phenylalanine identity of yeast tRNAPhe is governed by five nucleotides including residues A73, G20, and the three anticodon nucleotides (Sampson et al., 1989, Science 243, 1363-1366). Analysis of in vitro transcripts derived from yeast tRNAPhe and Escherichia coli tRNAAla bearing these recognition elements shows that phenylalanyl-tRNA synthetase is sensitive to additional nucleotides within the acceptor stem. Insertion of G2-C71 has dramatic negative effects in both tRNA frameworks. These effects become compensated by a second-site mutation, the insertion of the wobble G3-U70 pair, which by itself has no effect on phenylalanylation. From a mechanistic point of view, the G2-C71/G3-U70 combination is not a "classical" recognition element since its antideterminant effect is compensated for by a second-site mutation. This enlarges our understanding of tRNA identity that appears not only to be the outcome of a combination of positive and negative signals forming the so-called recognition/identity set but that is also based on the presence of nonrandom combinations of sequences elsewhere in tRNA. These sequences, we name "permissive elements," are retained by evolution so that they do not hinder aminoacylation. Likely, no nucleotide within a tRNA is of random nature but has been selected so that a tRNA can fulfill all its functions efficiently.journal articleresearch support, non-u.s. gov't1998 May 08importe

    : a cis antisense RNA operates in trans in S. aureus

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    International audienceAntisense RNAs (asRNAs) pair to RNAs expressed from the complementary strand, and their functions are thought to depend on nucleotide overlap with genes on the opposite strand. There is little information on the roles and mechanisms of asRNAs. We show that a cis asRNA acts in trans, using a domain outside its target complementary sequence. SprA1 small regulatory RNA (sRNA) and SprA1(AS) asRNA are concomitantly expressed in S. aureus. SprA1(AS) forms a complex with SprA1, preventing translation of the SprA1-encoded open reading frame by occluding translation initiation signals through pairing interactions. The SprA1 peptide sequence is within two RNA pseudoknots. SprA1(AS) represses production of the SprA1-encoded cytolytic peptide in trans, as its overlapping region is dispensable for regulation. These findings demonstrate that sometimes asRNA functional domains are not their gene-target complementary sequences, suggesting there is a need for mechanistic re-evaluation of asRNAs expressed in prokaryotes and eukaryotes

    Commissioning of the vacuum system of the KATRIN Main Spectrometer

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    The KATRIN experiment will probe the neutrino mass by measuring the beta-electron energy spectrum near the endpoint of tritium beta-decay. An integral energy analysis will be performed by an electro-static spectrometer (Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m^3, and a complex inner electrode system with about 120000 individual parts. The strong magnetic field that guides the beta-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300{\deg}C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.Comment: submitted for publication in JINST, 39 pages, 15 figure

    Efficacy and safety of immune checkpoint inhibitor rechallenge in individuals with hepatocellular carcinoma

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    BACKGROUND & AIMS: We investigated the efficacy and safety of immune checkpoint inhibitor (ICI) rechallenge in patients with hepatocellular carcinoma (HCC) who received ICI-based therapies in a previous systemic line. METHODS: In this international, retrospective multicenter study, patients with HCC who received at least two lines of ICI-based therapies (ICI-1, ICI-2) at 14 institutions were eligible. The main outcomes included best overall response and treatment-related adverse events. RESULTS: Of 994 ICI-treated patients screened, a total of 58 patients (male, n = 41; 71%) with a mean age of 65.0±9.0 years were included. Median systemic treatment lines of ICI-1 and ICI-2 were 1 (range, 1-4) and 3 (range, 2-9), respectively. ICI-based therapies used at ICI-1 and ICI-2 included ICI alone (ICI-1, n = 26, 45%; ICI-2, n = 4, 7%), dual ICI regimens (n = 1, 2%; n = 12, 21%), or ICI combined with targeted therapies/anti-VEGF (n = 31, 53%; n = 42, 72%). Most patients discontinued ICI-1 due to progression (n = 52, 90%). Objective response rate was 22% at ICI-1 and 26% at ICI-2. Responses at ICI-2 were also seen in patients who had progressive disease as best overall response at ICI-1 (n = 11/21; 52%). Median time-to-progression at ICI-1 and ICI-2 was 5.4 (95% CI 3.0-7.7) months and 5.2 (95% CI 3.3-7.0) months, respectively. Treatment-related adverse events of grade 3-4 at ICI-1 and ICI-2 were observed in 9 (16%) and 10 (17%) patients, respectively. CONCLUSIONS: ICI rechallenge was safe and resulted in a treatment benefit in a meaningful proportion of patients with HCC. These data provide a rationale for investigating ICI-based regimens in patients who progressed on first-line immunotherapy in prospective trials. IMPACT AND IMPLICATIONS: Therapeutic sequencing after first-line immune checkpoint inhibitor (ICI)-based therapy for advanced hepatocellular carcinoma (HCC) remains a challenge as no available second-line treatment options have been studied in immunotherapy-pretreated patients. Particularly, the role of ICI rechallenge in patients with HCC is unclear, as data from prospective trials are lacking. We investigated the efficacy and safety of ICI-based regimens in patients with HCC pretreated with immunotherapy in a retrospective, international, multicenter study. Our data provide the rationale for prospective trials investigating the role of ICI-based regimens in patients who have progressed on first-line immunotherapy

    Methodological study to evaluate the psychometric properties of FACIT-CD in a sample of Brazilian women with cervical intraepithelial neoplasia

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    Background: The occurrence of cervical intraepithelial neoplasia (CIN) is associated with changes in health-related quality of life, including psychological factors, such as fear and shame, and changes in sexuality and sexual satisfaction, such as decreased sexual desire and frequency of sexual intercourse. Personal relationships are the most affected because CIN is sexually transmitted and many women tend to blame their partner for disease transmission. The aim of this study was to evaluate the psychometric properties of the FACIT-CD questionnaire in Brazilian women diagnosed with CIN. Methods: The properties of the FACIT-CD questionnaire were tested on a sample of 439 women seen at the Department of Prevention of Barretos Cancer Hospital, including 329 patients who were diagnosed with CIN and 110 women who were not diagnosed with the disease. The analysed parameters included internal consistency (Cronbach's alpha), reproducibility (intraclass correlation coefficient), structural validity, convergent validity (correlation with the SF-12 and EORTC QLQ-CX24 questionnaires), discriminant validity (according to disease status, and self-rating of health), sensitivity, and responsiveness. Results: The Cronbach alpha values of the FACIT-CD scales were higher than 0.70 with the exception of the relationship scale (0.66). The FACIT-CD reproducibility was satisfactory, with variation in the intraclass correlation coefficients ranging between 0.50 and 0.83, although the 95% confidence interval (CI) was lower than 0.40 (0.33-0.64) on the treatment satisfaction scale. Regarding structural validity, only one item on the physical well-being scale was not kept in the original domain. The expected correlations between the FACIT-CD and SF-12 were not confirmed, whereas the correlations between the FACIT-CD and EORTC QLQ-CX24 were confirmed. The questionnaire was able to discriminate the groups according to disease status and self-rating of health. The sensitivity was low for the relationship scale and moderate for the other scales. The responsiveness of the FACIT-CD questionnaire varied between the groups that denominate the self-perception of health as no change, improvement or worsening. Conclusion: Our results are encouraging and indicate that the FACIT-CD questionnaire is a promising tool for the analysis of the quality of life of women with CIN.The postdoctoral fellowship was supported by Sao Paulo Research Foundation (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo - FAPESP, Sao Paulo, Brazil). Process number: FAPESP 2014/10158-3. The funding body had no role in the design of the study and collection, analysis and interpretation of data and in writing the manuscript.info:eu-repo/semantics/publishedVersio

    Satellite tobacco mosaic virus RNA: structure and implications for assembly

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    The initial appearance of 45% of the single-stranded RNA of satellite tobacco mosaic virus in electron density maps suggested the entire RNA conformation could be delineated. Subsequent work has localized nearly 80% of the RNA as stem-loop elements. Connection of the stem-loops in the most efficient manner produces a persuasive model for the encapsidated RNA. This arrangement has significant implications for virus assembly and for the essential role of RNA
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