319 research outputs found

    Anatomy of the Soft-Photon Approximation in Hadron-Hadron Bremsstrahlung

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    A modified Low procedure for constructing soft-photon amplitudes has been used to derive two general soft-photon amplitudes, a two-s-two-t special amplitude MμTsTtsM^{TsTts}_{\mu} and a two-u-two-t special amplitude MμTuTtsM^{TuTts}_{\mu}, where s, t and u are the Mandelstam variables. MμTsTtsM^{TsTts}_{\mu} depends only on the elastic T-matrix evaluated at four sets of (s,t) fixed by the requirement that the amplitude be free of derivatives (\partialT/\partials and /or \partialT/t\partial t). Likewise MμTuTtsM^{TuTts}_{\mu} depends only on the elastic T-matrix evaluated at four sets of (u,t). In deriving these amplitudes, we impose the condition that MμTsTtsM^{TsTts}_{\mu} and MμTuTtsM^{TuTts}_{\mu} reduce to MˉμTsTts\bar{M}^{TsTts}_{\mu} and MˉμTuTts\bar{M}^{TuTts}_{\mu}, respectively, their tree level approximations. The amplitude MˉμTsTts\bar{M}^{TsTts}_{\mu} represents photon emission from a sum of one-particle t-channel exchange diagrams and one-particle s-channel exchange diagrams, while the amplitude MˉμTuTts\bar{M}^{TuTts} _{\mu} represents photon emission from a sum of one-particle t-channel exchange diagrams and one-particle u-channel exchange diagrams. The precise expressions for MˉμTsTts\bar{M}^{TsTts}_{\mu} and MˉμTuTts\bar{M}^{TuTts}_{\mu} are determined by using the radiation decomposition identities of Brodsky and Brown. We point out that it is theoretically impossible to describe all bremsstrahlung processes by using only a single class of soft-photon amplitudes. At least two different classes are required: the amplitudes which depend on s and t or the amplitudes which depend on u and t. When resonance effects are important, the amplitude MμTsTtsM^{TsTts}_{\mu}, not MμLow(st)M^{Low(st)}_{\mu}, should be used. For processes with strong u-channel exchange effects, the amplitude MμTuTtsM^{TuTts}_{\mu} should be the first choice.Comment: 49 pages report # LA-UR-92-270

    Overweight and obesity status from the prenatal period to adolescence and its association with non- alcoholic fatty liver disease in young adults: cohort study

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/16/bjo16199-sup-0005-ICMJES2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/15/bjo16199-sup-0012-ICMJES12.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/14/bjo16199_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/13/bjo16199-sup-0010-ICMJES10.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/12/bjo16199-sup-0002-TableS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/11/bjo16199.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/10/bjo16199-sup-0007-ICMJES4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/9/bjo16199-sup-0008-ICMJES5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/8/bjo16199-sup-0006-ICMJES3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/7/bjo16199-sup-0003-AppendixS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/6/bjo16199-sup-0011-ICMJES11.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/5/bjo16199-sup-0013-ICMJES13.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/4/bjo16199-sup-0014-ICMJES14.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/3/bjo16199-sup-0001-FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/2/bjo16199-sup-0009-ICMJES6.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156435/1/bjo16199-sup-0004-ICMJES1.pd

    6-Thioguanine blocks SARS-CoV-2 replication by inhibition of PLpro

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    The emergence of SARS-CoV-2 has led to a global health crisis that, in addition to vaccines and immunomodulatory therapies, calls for the identification of antiviral therapeutics. The papain-like protease (PLpro) activity of nsp3 is an attractive drug target as it is essential for viral polyprotein cleavage and for deconjugation of ISG15, an antiviral ubiquitin-like protein. We show here that 6-Thioguanine (6-TG), an orally available and widely available generic drug, inhibits SARS-CoV-2 replication in Vero-E6 cells with an EC50 of approximately 2 μM. 6-TG also inhibited PLpro-catalyzed polyprotein cleavage and de-ISGylation in cells and inhibited proteolytic activity of the purified PLpro domai

    Particles at oil–air surfaces : powdered oil, liquid oil marbles, and oil foam

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    The type of material stabilized by four kinds of fluorinated particles (sericite and bentonite platelet clays and spherical zinc oxide) in air–oil mixtures has been investigated. It depends on the particle wettability and the degree of shear. Upon vigorous agitation, oil dispersions are formed in all the oils containing relatively large bentonite particles and in oils of relatively low surface tension (γla < 26 mN m⁻¹) like dodecane, 20 cS silicone, and cyclomethicone containing the other fluorinated particles. Particle-stabilized oil foams were obtained in oils having γla > 26 mN m⁻¹ where the advancing air–oil–solid contact angle θ lies between ca. 90° and 120°. Gentle shaking, however, gives oil-in-air liquid marbles with all the oil–particle systems except for cases where θ is <60°. For oils of tension >24 mN m⁻¹ with omniphobic zinc oxide and sericite particles for which advancing θ ≥ 90°, dry oil powders consisting of oil drops in air which do not leak oil could be made upon gentle agitation up to a critical oil:particle ratio (COPR). Above the COPR, catastrophic phase inversion of the dry oil powders to air-in-oil foams was observed. When sheared on a substrate, the dry oil powders containing at least 60 wt % of oil release the encapsulated oil, making these materials attractive formulations in the cosmetic and food industries

    Gemcitabine and cisplatin in a multimodality treatment for locally advanced non-small cell lung cancer

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    The role of new cytotoxic agents like gemcitabine has not yet been proven in the neoadjuvant settings. We designed a phase II study to test the feasibility of using gemcitabine and cisplatin before local treatment for stage III non-small cell lung cancer patients. Patients received three cycles of induction chemotherapy of gemcitabine (1000 mg m−2, days 1, 8, 15) and cisplatin (90 mg m−2, day 15) every 4 weeks before evaluation for operability. Operable patients underwent radical resection. Inoperable patients and patients who had incomplete resection received concurrent chemoradiotherapy with daily low dose cisplatin. All patients who did not progress after local treatment received three more cycles of adjuvant chemotherapy of gemcitabine and cisplatin. Fifty-two patients received induction treatment. Two patients had complete response and 31 patients had partial response (response rate 63.5%) after induction chemotherapy. Thirty-six patients (69%) were operable. Eighteen patients (35%) had their tumours completely resected. Two patients had pathological complete response. Median overall survival was 19.1 months, projected 1-year survival was 66% and 2-year survival was 34%. Three cycles of gemcitabine and cisplatin is effective and can be used as induction treatment before surgery for locally advanced non-small cell lung cancer patients

    Associations of Neighborhood Opportunity and Social Vulnerability With Trajectories of Childhood Body Mass Index and Obesity Among US Children

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    IMPORTANCE: Physical and social neighborhood attributes may have implications for children\u27s growth and development patterns. The extent to which these attributes are associated with body mass index (BMI) trajectories and obesity risk from childhood to adolescence remains understudied. OBJECTIVE: To examine associations of neighborhood-level measures of opportunity and social vulnerability with trajectories of BMI and obesity risk from birth to adolescence. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used data from 54 cohorts (20 677 children) participating in the Environmental Influences on Child Health Outcomes (ECHO) program from January 1, 1995, to January 1, 2022. Participant inclusion required at least 1 geocoded residential address and anthropometric measure (taken at the same time or after the address date) from birth through adolescence. Data were analyzed from February 1 to June 30, 2022. EXPOSURES: Census tract-level Child Opportunity Index (COI) and Social Vulnerability Index (SVI) linked to geocoded residential addresses at birth and in infancy (age range, 0.5-1.5 years), early childhood (age range, 2.0-4.8 years), and mid-childhood (age range, 5.0-9.8 years). MAIN OUTCOMES AND MEASURES: BMI (calculated as weight in kilograms divided by length [if aged \u3c2 \u3eyears] or height in meters squared) and obesity (age- and sex-specific BMI ≥95th percentile). Based on nationwide distributions of the COI and SVI, Census tract rankings were grouped into 5 categories: very low (\u3c20th \u3epercentile), low (20th percentile to \u3c40th \u3epercentile), moderate (40th percentile to \u3c60th \u3epercentile), high (60th percentile to \u3c80th \u3epercentile), or very high (≥80th percentile) opportunity (COI) or vulnerability (SVI). RESULTS: Among 20 677 children, 10 747 (52.0%) were male; 12 463 of 20 105 (62.0%) were White, and 16 036 of 20 333 (78.9%) were non-Hispanic. (Some data for race and ethnicity were missing.) Overall, 29.9% of children in the ECHO program resided in areas with the most advantageous characteristics. For example, at birth, 26.7% of children lived in areas with very high COI, and 25.3% lived in areas with very low SVI; in mid-childhood, 30.6% lived in areas with very high COI and 28.4% lived in areas with very low SVI. Linear mixed-effects models revealed that at every life stage, children who resided in areas with higher COI (vs very low COI) had lower mean BMI trajectories and lower risk of obesity from childhood to adolescence, independent of family sociodemographic and prenatal characteristics. For example, among children with obesity at age 10 years, the risk ratio was 0.21 (95% CI, 0.12-0.34) for very high COI at birth, 0.31 (95% CI, 0.20-0.51) for high COI at birth, 0.46 (95% CI, 0.28-0.74) for moderate COI at birth, and 0.53 (95% CI, 0.32-0.86) for low COI at birth. Similar patterns of findings were observed for children who resided in areas with lower SVI (vs very high SVI). For example, among children with obesity at age 10 years, the risk ratio was 0.17 (95% CI, 0.10-0.30) for very low SVI at birth, 0.20 (95% CI, 0.11-0.35) for low SVI at birth, 0.42 (95% CI, 0.24-0.75) for moderate SVI at birth, and 0.43 (95% CI, 0.24-0.76) for high SVI at birth. For both indices, effect estimates for mean BMI difference and obesity risk were larger at an older age of outcome measurement. In addition, exposure to COI or SVI at birth was associated with the most substantial difference in subsequent mean BMI and risk of obesity compared with exposure at later life stages. CONCLUSIONS AND RELEVANCE: In this cohort study, residing in higher-opportunity and lower-vulnerability neighborhoods in early life, especially at birth, was associated with a lower mean BMI trajectory and a lower risk of obesity from childhood to adolescence. Future research should clarify whether initiatives or policies that alter specific components of neighborhood environment would be beneficial in preventing excess weight in children

    Computational Characterization of 3′ Splice Variants in the GFAP Isoform Family

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    Glial fibrillary acidic protein (GFAP) is an intermediate filament (IF) protein specific to central nervous system (CNS) astrocytes. It has been the subject of intense interest due to its association with neurodegenerative diseases, and because of growing evidence that IF proteins not only modulate cellular structure, but also cellular function. Moreover, GFAP has a family of splicing isoforms apparently more complex than that of other CNS IF proteins, consistent with it possessing a range of functional and structural roles. The gene consists of 9 exons, and to date all isoforms associated with 3′ end splicing have been identified from modifications within intron 7, resulting in the generation of exon 7a (GFAPδ/ε) and 7b (GFAPκ). To better understand the nature and functional significance of variation in this region, we used a Bayesian multiple change-point approach to identify conserved regions. This is the first successful application of this method to a single gene – it has previously only been used in whole-genome analyses. We identified several highly or moderately conserved regions throughout the intron 7/7a/7b regions, including untranslated regions and regulatory features, consistent with the biology of GFAP. Several putative unconfirmed features were also identified, including a possible new isoform. We then integrated multiple computational analyses on both the DNA and protein sequences from the mouse, rat and human, showing that the major isoform, GFAPα, has highly conserved structure and features across the three species, whereas the minor isoforms GFAPδ/ε and GFAPκ have low conservation of structure and features at the distal 3′ end, both relative to each other and relative to GFAPα. The overall picture suggests distinct and tightly regulated functions for the 3′ end isoforms, consistent with complex astrocyte biology. The results illustrate a computational approach for characterising splicing isoform families, using both DNA and protein sequences
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