172 research outputs found
Corridor Volatility Risk and Expected Returns
This paper examines the pricing of volatility risk using SPX corridor implied volatility. We decompose model-free implied volatility into various components using different segments of the cross-section of out-of-the money put and call option prices. We find that only model-free volatility computed from the cross-section of out-of-the-money call option prices carries a significant negative risk premium in the cross-section of stock returns and subsumes all relevant information for forecasting future volatility. Our empirical results provide strong evidence that SPX out-of-the money put option prices do not contain useful information for pricing aggregate volatility risk in the cross-section of stock returns
Leaving A Bequest: Living on Through Charitable Gifts
Decisions taken in respect of the disposition of possessions often parallel a life transition or change in identity. In this article, we examine decisions taken in a will where disposition can be viewed not as a representation of the identities an individual wishes to shed, but rather as the continuation of those for which the deceased wishes to be remembered. We examine the meaning that such donors ascribe to their giving and the rich pattern of utility it offers both the individual and those he or she will ultimately leave behind. Using grounded theory, we report the results of 20 in-depth interviews conducted with individuals who had pledged a bequest to at least one U.K. charity. We demonstrate how the bequest gift is laden with symbolism, a function of the reminiscences of the individual and reflective of the need for the self to live on and achieve a degree of symbolic immortality
Distinct Regions of the Large Extracellular Domain of Tetraspanin CD9 Are Involved in the Control of Human Multinucleated Giant Cell Formation
Multinucleated giant cells, formed by the fusion of monocytes/macrophages, are features of chronic granulomatous inflammation associated with infections or the persistent presence of foreign material. The tetraspanins CD9 and CD81 regulate multinucleated giant cell formation: soluble recombinant proteins corresponding to the large extracellular domain (EC2) of human but not mouse CD9 can inhibit multinucleated giant cell formation, whereas human CD81 EC2 can antagonise this effect. Tetraspanin EC2 are all likely to have a conserved three helix sub-domain and a much less well-conserved or hypervariable sub-domain formed by short helices and interconnecting loops stabilised by two or more disulfide bridges. Using CD9/CD81 EC2 chimeras and point mutants we have mapped the specific regions of the CD9 EC2 involved in multinucleated giant cell formation. These were primarily located in two helices, one in each sub-domain. The cysteine residues involved in the formation of the disulfide bridges in CD9 EC2 were all essential for inhibitory activity but a conserved glycine residue in the tetraspanin-defining ‘CCG’ motif was not. A tyrosine residue in one of the active regions that is not conserved between human and mouse CD9 EC2, predicted to be solvent-exposed, was found to be only peripherally involved in this activity. We have defined two spatially-distinct sites on the CD9 EC2 that are required for inhibitory activity. Agents that target these sites could have therapeutic applications in diseases in which multinucleated giant cells play a pathogenic role
R-Spondin3 is associated with basal-progenitor behavior in normal and tumor mammary cells
R-spondin3 (RSPO3) is a member of a family of secreted proteins that enhance Wnt signaling pathways in diverse processes, including cancer. However, the role of RSPO3 in mammary gland and breast cancer development remains unclear. In this study, we show that RSPO3 is expressed in the basal stem cell–enriched compartment of normal mouse mammary glands but is absent from committed mature luminal cells in which exogenous RSPO3 impairs lactogenic differentiation. RSPO3 knockdown in basal-like mouse mammary tumor cells reduced canonical Wnt signaling, epithelial-to-mesenchymal transition-like features, migration capacity, and tumor formation in vivo. Conversely, RSPO3 overexpression, which was associated with some LGR and RUNX factors, highly correlated with the basal-like subtype among patients with breast cancer. Thus, we identified RSPO3 as a novel key modulator of breast cancer development and a potential target for treatment of basal-like breast cancers. Significance: These findings identify RSPO3 as a potential therapetuic target in basal-like breast cancers. Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/16/4497/F1.large.jpg.Fil: Tocci, Johanna Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Felcher, Carla María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Garcia Sola, Martin Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Goddio, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Zimberlin, Maria Noel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Rubinstein, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Srebrow, Anabella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Coso, Omar Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Abba, Martín Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Meissl, Roberto Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Kordon, Edith Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin
Soft Poly(dimethylsiloxane) Elastomers from Architecture-Driven Entanglement Free Design
We fabricate soft, solvent-free polydimethylsiloxane (PDMS) elastomers by crosslinking bottlebrush polymers rather than linear polymers. We design the chemistry to allow commercially available linear PDMS precursors to deterministically form bottlebrush polymers, which are simultaneously crosslinked, enabling a one-step synthesis. The bottlebrush architecture prevents the formation of entanglements, resulting in elastomers with precisely controllable elastic moduli from ~1 to ~100 kPa, below the intrinsic lower limit of traditional elastomers. Moreover, the solvent-free nature of the soft PDMS elastomers enables a negligible contact adhesion compared to commercially available silicone products of similar stiffness. The exceptional combination of softness and negligible adhesiveness may greatly broaden the applications of PDMS elastomers in both industry and research
Super-soft and super-elastic dry gels
Molecular combs and bottlebrushes are a new class of polymer architecture allowing for anomalously low density of entanglements in polymer melts. The conformations and rheological properties of melts of these branched macromolecule composed of a flexible backbone and side chains densely tethered to it are investigated theoretically, experimentally and by computer simulations.1,2 We develop the rule for dialing in the desired value of the melt plateau modulus of these molecules as low as 1000 times below the conventional values for linear polymer melts and experimentally verify the validity of our theory. The theory also predicts that elastomers made from these melts should be super-elastic and reversibly stretch up to ten times more than elastomers made from linear polymers. Hybrid networks with both permanent and reversible bonds made with this novel architecture are predicted to be super-tough and self-healing.
References W.F.M. Daniel, J. Burdynska, M. Vatankhah-Varnoosfaderani, K. Matyjaszewski, J. Paturej, M. Rubinstein, A.V. Dobrynin and S.S. Sheiko, Nature Materials, 2016, 15, 183-190. L.H Cai, T.E. Kodger, R.E. Guerra, A.F. Pegoraro, M. Rubinstein, and D.A. Weitz, Advanced Materials 2015, 27, 5132–5140
In Vivo Assessment of Neuroinflammation in 4-Repeat Tauopathies
Background: Neuroinflammation has received growing interest as a therapeutic target in neurodegenerative disorders, including 4-repeat tauopathies. Objectives: The aim of this cross-sectional study was to investigate 18 kDa translocator protein positron emission tomography (PET) as a biomarker for microglial activation in the 4-repeat tauopathies corticobasal degeneration and progressive supranuclear palsy. Methods Specific binding of the 18 kDa translocator protein tracer F-18-GE-180 was determined by serial PET during pharmacological depletion of microglia in a 4-repeat tau mouse model. The 18 kDa translocator protein PET was performed in 30 patients with corticobasal syndrome (68 +/- 9 years, 16 women) and 14 patients with progressive supranuclear palsy (69 +/- 9 years, 8 women), and 13 control subjects (70 +/- 7 years, 7 women). Group comparisons and associations with parameters of disease progression were assessed by region-based and voxel-wise analyses. Results Tracer binding was significantly reduced after pharmacological depletion of microglia in 4-repeat tau mice. Elevated 18 kDa translocator protein labeling was observed in the subcortical brain areas of patients with corticobasal syndrome and progressive supranuclear palsy when compared with controls and was most pronounced in the globus pallidus internus, whereas only patients with corticobasal syndrome showed additionally elevated tracer binding in motor and supplemental motor areas. The 18 kDa translocator protein labeling was not correlated with parameters of disease progression in corticobasal syndrome and progressive supranuclear palsy but allowed sensitive detection in patients with 4-repeat tauopathies by a multiregion classifier. Conclusions: Our data indicate that F-18-GE-180 PET detects microglial activation in the brain of patients with 4-repeat tauopathy, fitting to predilection sites of the phenotype. The 18 kDa translocator protein PET has a potential for monitoring neuroinflammation in 4-repeat tauopathies. (c) 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Societ
Comparison of different prognostic scores for patients with cirrhosis hospitalized with SARS-CoV-2 infection
Introduction and Objectives: Viral infections have been described to increase the risk of decompensation in patients with cirrhosis. We aimed to determine the effect of SARS-CoV-2 infection on outcome of hospitalized patients with cirrhosis and to compare the performance of different prognostic models for predicting mortality. Patients: We performed a prospective cohort study including 2211 hospitalized patients with confirmed SARS-CoV-2 infection from April 15, 2020 through October 1, 2020 in 38 Hospitals from 11 Latin American countries. We registered clinical and laboratory parameters of patients with and without cirrhosis. All patients were followed until discharge or death. We evaluated the prognostic performance of different scoring systems to predict mortality in patients with cirrhosis using ROC curves. Results: Overall, 4.6% (CI 3.7–5.6) subjects had cirrhosis (n = 96). Baseline Child-Turcotte-Pugh (CTP) class was assessed: CTP-A (23%), CTP-B (45%) and CTP-C (32%); median MELD-Na score was 19 (IQR 14−25). Mortality was 47% in patients with cirrhosis and 16% in patients without cirrhosis (P 30. The areas under the ROC curves for performance evaluation in predicting 28-days mortality for Chronic Liver Failure Consortium (CLIF-C), North American Consortium for the Study of End-Stage Liver Disease (NACSELD), CTP score and MELD-Na were 0.85, 0.75, 0.69, 0.67; respectively (P < .0001). Conclusions: SARS-CoV-2 infection is associated with elevated mortality in patients with cirrhosis. CLIFC had better performance in predicting mortality than NACSELD, CTP and MELD-Na in patients with cirrhosis and SARS-CoV-2 infection. Clinicaltrials.gov:NCT04358380.Fil: Mendizabal, Manuel. Universidad Austral; Argentina. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; ArgentinaFil: Ridruejo, Ezequiel. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; Argentina. Centro de Educación Médica e Investigaciones Clínicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Piñero, Federico. Universidad Austral; Argentina. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; ArgentinaFil: Anders, Margarita. Hospital Alemán; Argentina. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; ArgentinaFil: Padilla, Martín Jesus. Hospital Nacional Guillermo Almenara Irigoyen; PerúFil: Toro, Luis G.. Fundación de Medellín y Rionegro; ColombiaFil: Torre, Aldo. Instituto Nacional de Ciencias Médicas y Nutrición; MéxicoFil: Montes, Pedro. Hospital Nacional Daniel A. Carrión; ArgentinaFil: Urzúa, Alvaro. Universidad de Chile; ChileFil: Gonzalez Ballerga, Esteban. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Silveyra, María Dolores. Sanatorio Anchorena; ArgentinaFil: Michelato, Douglas. Hospital Especializado en Enfermedades Infecciosas Instituto Couto Maia; BrasilFil: Díaz, Javier. Hospital Nacional Edgardo Rebagliati Martins; PerúFil: Peralta, Mirta. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: Pages, Josefina. Universidad Austral; Argentina. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; ArgentinaFil: García, Sandro Ruiz. Hospital de Víctor Lazarte Echegaray; PerúFil: Gutierrez Lozano, Isabel. Centro Médico ABC; MéxicoFil: Macias, Yuridia. IMSS Hospital General Regional No. 1 “Dr. Carlos Mc Gregor Sánchez”; MéxicoFil: Cocozzella, Daniel. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; Argentina. Hospital Italiano de La Plata; ArgentinaFil: Chavez Tapia, Norberto. Medica Sur Clinic & Foundation; MéxicoFil: Tagle, Martín. Clínica Anglo-Americana; PerúFil: Dominguez, Alejandra. Hospital Padre Hurtado; ChileFil: Varón, Adriana. Red Latinoamericana de Concientización y Educación en Investigación del Hígado; Argentina. Fundación Cardio Infantil; ColombiaFil: Vera Pozo, Emilia. Hospital Regional Dr. Teodoro Maldonado Carbo del IESS; EcuadorFil: Higuera de la Tijera, Fátima. Hospital General de México “Dr. Eduardo Liceaga”; MéxicoFil: Bustios, Carla. Fundación Cardio Infantil; ColombiaFil: Conte, Damián. Hospital Privado de Córdoba; ArgentinaFil: Escajadillo, Nataly. Universidad Austral; ArgentinaFil: Rubinstein, Fernando Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Especializado en Enfermedades Infecciosas Instituto Couto Maia; BrasilFil: Tenorio, Laura. Hospital Nacional Edgardo Rebagliati Martins; Per
Intentional injury reported by young people in the Federated States of Micronesia, Kingdom of Tonga and Vanuatu
<p>Abstract</p> <p>Background</p> <p>Intentional injury presents a threat to the physical and psychological well being of young people, especially in developing countries, which carry the greatest part of the global injury burden. While the importance of this problem is recognized, there are limited population data in low and middle income countries that can guide public health action. The present study investigates the prevalence and distribution of intentional injury among young people in three Pacific Island societies, and examines behavioural and psychosocial factors related to risk of intentional injury.</p> <p>Methods</p> <p>Population surveys were conducted with <b>s</b>tudents aged 11–17 years in Pohnpei State in the Federated States of Micronesia (n = 1495), the Kingdom of Tonga (n = 2808) and Vanuatu (n = 4474). Surveys measured self-reported injury and intentional injury, sources of intentional injury, and the range of behavioural, psychological, educational and social variables that may be related to injury risk.</p> <p>Results</p> <p>Among boys and girls aged 14–17 years the respective period prevalence of intentional injury was 62% and 56% in Pohnpei, 58% and 41% in Tonga, and 33% and 24% in Vanuatu. The prevalence of intentional injury declined with age in Tonga and Vanuatu, but there was little evidence of an age-trend in Pohnpei. Across the three societies, the major sources of intentional injury among boys were 'other persons' followed by boyfriends/girlfriends and fathers. Mothers, boyfriends/girlfriends and other persons were primary sources of injury among girls. An intentional injury was reported more often by those who had been bullied (OR 1.40–1.66, P < 0.05), by regular smokers in Tonga and Vanuatu (OR 1.52–2.21, P < 0.05), and illicit drug users in Pohnpei and Vanuatu (OR 1.87–1.92, P < 0.05).</p> <p>Conclusion</p> <p>Intentional injury was reported extensively in these three populations. Interventions directed towards the school environment and which take into account the role of bullying and drug use need to be considered.</p
Prospective Latin American cohort evaluating outcomes of patients with COVID-19 and abnormal liver tests on admission
Introduction & objectives: The independent effect of liver biochemistries as a prognostic factor in patients with COVID-19 has not been completely addressed. We aimed to evaluate the prognostic value of abnormal liver tests on admission of hospitalized patients with COVID-19. Materials & methods: We performed a prospective cohort study including 1611 hospitalized patients with confirmed SARS-CoV-2 infection from April 15, 2020 through July 31, 2020 in 38 different Hospitals from 11 Latin American countries. We registered clinical and laboratory parameters, including liver function tests, on admission and during hospitalization. All patients were followed until discharge or death. We fit multivariable logistic regression models, further post-estimation effect through margins and inverse probability weighting. Results: Overall, 57.8% of the patients were male with a mean age of 52.3 years, 8.5% had chronic liver disease and 3.4% had cirrhosis. Abnormal liver tests on admission were present on 45.2% (CI 42.7–47.7) of the cohort (n = 726). Overall, 15.1% (CI 13.4–16.9) of patients died (n = 244). Patients with abnormal liver tests on admission presented higher mortality 18.7% (CI 15.9–21.7), compared to those with normal liver biochemistries 12.2% (CI 10.1–14.6); P 30. Conclusions: The presence of abnormal liver tests on admission is independently associated with mortality and severe COVID-19 in hospitalized patients with COVID-19 infection and may be used as surrogate marker of inflammation.Fil: Mendizabal, Manuel. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Piñero, Federico. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Ridruejo, Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; ArgentinaFil: Anders, Margarita. Hospital Aleman; ArgentinaFil: Silveyra, María Dolores. Sanatorio Anchorena; ArgentinaFil: Torre, Aldo. Centro Médico ABC; MéxicoFil: Montes, Pedro. Hospital Nacional Daniel A. Carrión; PerúFil: Urzúa, Alvaro. Hospital Clínico de la Universidad de Chile; ChileFil: Pages, Josefina. Universidad Austral. Hospital Universitario Austral; ArgentinaFil: Toro, Luis G.. Hospitales de San Vicente Fundación de Medellín y Rionegro; ColombiaFil: Díaz, Javier. Hospital Nacional Edgardo Rebagliati Martins; PerúFil: Gonzalez Ballerga, Esteban. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Miranda Zazueta, Godolfino. Instituto Nacional de Ciencias Médicas y Nutrición; MéxicoFil: Peralta, Mirta. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: Gutiérrez, Isabel. Centro Médico ABC; MéxicoFil: Michelato, Douglas. Hospital Especializado en Enfermedades Infecciosas Instituto Couto Maia; BrasilFil: Venturelli, Maria Grazia. Hospital Nacional Guillermo Almenara Irigoyen; PerúFil: Varón, Adriana. Fundación Cardio-Infantil; ColombiaFil: Vera Pozo, Emilia. Hospital Regional Dr. Teodoro Maldonado Carbo; EcuadorFil: Tagle, Martín. Clínica Anglo-Americana; PerúFil: García, Matías. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Tassara, Alfredo. Hospital Aleman; ArgentinaFil: Brutti, Julia. Sanatorio Anchorena; ArgentinaFil: Ruiz García, Sandro. Hospital de Víctor Lazarte Echegaray; PerúFil: Bustios, Carla. Clínica Delgado; PerúFil: Escajadillo, Nataly. Hospital Nacional Almanzor Aguinaga Asenjo; PerúFil: Macias, Yuridia. No especifíca;Fil: Higuera de la Tijera, Fátima. Hospital General de México “Dr. Eduardo Liceaga"; MéxicoFil: Gómez, Andrés J.. Hospital Universitario Fundación Santa Fé de Bogotá; ColombiaFil: Dominguez, Alejandra. Hospital Padre Hurtado; ChileFil: Castillo Barradas, Mauricio. Hospital de Especialidades del Centro Médico Nacional La Raza; MéxicoFil: Contreras, Fernando. No especifíca;Fil: Scarpin, Aldana. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Schinoni, Maria Isabel. Hospital Alianza; BrasilFil: Toledo, Claudio. Universidad Austral de Chile; ChileFil: Girala, Marcos. Universidad Nacional de Asunción; ParaguayFil: Mainardi, Victoria. Hospital Central De las Fuerzas Armadas; UruguayFil: Sanchez, Abel. Hospital Roosevelt; GuatemalaFil: Bessone, Fernando. Provincia de Santa Fe. Ministerio de Salud y Medio Ambiente - Rosario. Hospital Provincial del Centenario; ArgentinaFil: Rubinstein, Fernando Adrian. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Silva, Marcelo Oscar. Universidad Austral. Hospital Universitario Austral; Argentin
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