2,455 research outputs found
Related Message Attacks to Public Key Encryption Schemes: Relations among Security Notions
Consider a scenario in which an adversary, attacking a certain public key encryption scheme, gains knowledge of several ciphertexts
which underlying plaintext are meaningfully related with a given target ciphertext. This kind of
related message attack has been proved
successful against several public key encryption schemes; widely
known is the Franklin-Reiter attack to RSA with low exponent and
its subsequent improvement by Coppersmith. However, to the best of
our knowledge no formal treatment of these type of attacks has to
date been done, and as a result, it has not been rigorously studied which of the ``standard\u27\u27 security notions
imply resilience to them.
We give formal definitions of several security
notions capturing the resistance to this kind of attacks. For
passive adversaries we prove that, for the case of
indistinguishability, security against related message attacks is
equivalent to standard CPA security. On the other hand,
one-wayness robust schemes in this sense can be seen as
strictly between OW-CPA and IND-CPA secure schemes.
Furthermore, we prove that the same holds for active (CCA)
adversaries
Group key exchange protocols withstanding ephemeral-key reveals
When a group key exchange protocol is executed, the session key is typically extracted from two types of secrets; long-term keys (for authentication) and freshly generated (often random) values. The leakage of this latter so-called ephemeral keys has been extensively analyzed in the 2-party case, yet very few works are concerned with it in the group setting. We provide a generic {group key exchange} construction that is strongly secure, meaning that the attacker is allowed to learn both long-term and ephemeral keys (but not both from the same participant, as this would trivially disclose the session key). Our design can be seen as a compiler, in the sense that it builds on a 2-party key exchange protocol which is strongly secure and transforms it into a strongly secure group key exchange protocol by adding only one extra round of communication. When applied to an existing 2-party protocol from Bergsma et al., the result is a 2-round group key exchange protocol which is strongly secure in the standard model, thus yielding the first construction with this property
Haloargentinum marplatensis gen. nov., sp. nov., a novel extremely halophilic bacterium isolated from salted-ripened anchovy (Engraulis anchoita)
A facultative aerobic, Gram-negative, motile, non-endospore forming and extremely halophilic bacterium, strain 11aii⊺, isolated from salted-ripened anchovy, was examined using a polyphasic approach to characterize and clarify its phylogenetic and taxonomic position. Sequences of the 16S rRNA gene revealed close relationships to species of the genera Lentibacillus and Virgibacillus (94.2% similarity). The organism grew optimally in the presence of 20-35 % NaCl. The major fatty acids of strain 11aii⊺ were C16:0 (42.1%) and anteiso-C15:0 (31.2%) and also presented iso-C16:0 (11.0%), anteiso-C17:0 (10.4%) and C18:0 (5.2%). Based on data presented here, strain 11aii⊺ is considered to represent a novel genus and species, for which the name Haloargentinum marplatensis gen. nov. sp. nov. is proposed with the strain 11aii⊺ as type strain.Fil: Perez, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; ArgentinaFil: Gomila, Margarita. Universitat de les Illes Balears; EspañaFil: Murialdo, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Ingeniería Bioquímica; ArgentinaFil: Ameztoy, Irene Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; ArgentinaFil: Gonzalez Escalona, Narjol. Center For Food Safety And Applied Nutrition; Estados UnidosFil: Ramirez, Elida Elvia. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; ArgentinaFil: Yeannes, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; Argentin
Genesis and evolution of the San Manuel iron skarn deposit (Betic Cordillera, SW Spain)
The San Manuel magnesian skarn is an iron deposit hosted in dolomitic marbles from a tectonic slice imbricated within the Ronda peridotites, in the westernmost part of the Betic Cordillera, Spain. According to the dominant mineral assemblage, the skarn is subdivided into three different zones, (1) forsterite +/- calcite skarn, (2) calcite +/- chlorite +/- serpentine skarn, and (3) Ca-amphibole skarn. The main ore in the skarn is a similar to 2.5 m thick, massive ore body situated in the middle of the sequence. In this paper, we firstly report a comprehensive major to trace element composition, texture, microstructure, and mineralogy characterization for zoned magnesioferritemagnetite grains of the San Manuel deposit using a combination of (1) laser ablation inductively coupled plasma mass spectrometer, (2) focused ion beam combined with transmission electron microscopy, and (3) electron back-scattered diffraction. We have defined four different magnesioferrite-magnetite generations. A complete sequence of zoning includes cores of magnesioferrite (Mag-1; MgO up to 10.6 wt%) overprinted by three successive generations of magnetite, namely Mag-2, Mag-3, Mag-4. Mag-2 (MgO < 4 wt%), hosts composite forsterite +/- calcite +/- chlorite inclusions, consistently with high Si, Ca, and Sr (average: 8204 ppm, 8980 ppm, and 49 ppm respectively) contents detected by in situ laser ablation inductively coupled plasma (LA-ICP-MS). Mag-3 replacing former Mag-1 and Mag-2 includes nanometric spinel and gahnite exsolutions detected by focused ion beam combined with a transmission electron microscope (FIB-TEM), which is consistent with its high Al, Ti, V, and Ga (average: 5073 ppm, 368 ppm, and 20 ppm, respectively) trace element concentration. Mag-4 is the Fe-richest magnetite (up to 94.16 wt% FeOtotal) forming the outermost rims in magnetite grains, and exhibiting the lowest total trace element contents. Approaches in temperature estimations employing magnetitespinel exsolutions in Mag-3 suggest that the minimum temperature of the prograde stage reached temperatures below 700 degrees C, whereas Mag-4 should be formed during the retrograde stage. Magnetite microstructure studied by electron backscatter diffraction (EBSD) suggests Mag-4 formation under fluid-assisted dynamic conditions, which is consistent with the tectonic evolution of the emplacement. We propose that the San Manuel deposit formed by pulsed hydrothermal fluids derived from anatexis of crustal rocks during peridotite emplacement, promoting reequilibration processes that led to the magnesioferrite-magnetite zoning
Promotion of physical activity after hospitalization for COPD exacerbation: A randomized control trial
COPD exacerbation; Hospitalization; Physical activityExacerbació de la MPOC; Hospitalització; Activitat físicaExacerbación de la EPOC; Hospitalización; Actividad físicaBackground and Objective
Physical activity worsens during exacerbations of chronic obstructive pulmonary disease (COPD) and notably after hospitalizations. Pedometer-based interventions are useful to increase physical activity in stable patients with COPD. However, there is little information concerning the implementation of such programs following severe exacerbation. This study assessed the efficacy of a physical activity program after hospitalization for a COPD exacerbation.
Methods
We performed a prospective, 12-week, parallel group, assessor-blinded, randomized control trial in COPD patients hospitalized for an exacerbation. After discharge, physical activity and other secondary variables were assessed. Patients were allocated (1:1) to a physical activity promotion program (intervention group, IG) or usual care (control group, CG). Based on a motivational interview and accelerometer physical activity assessment, a patient-tailored, pedometer-based, progressive and target-driven program was designed. Linear mixed effect models were used to analyse between-group differences.
Results
Forty-six out of 61 patients recruited were randomized and 43 (IG = 20, CG = 23) completed the study. In-hospital and baseline characteristics were similar in both groups. After 12 weeks of intervention, the mean steps difference between groups was 2093 steps/day, p = 0.018, 95% CI 376–4012, favouring the IG. Only the IG significantly increased the number of steps/day compared to baseline (mean difference [95% CI] 2932 [1069–4795] steps; p = 0.004). There were no other between-group differences.
Conclusion
After hospitalization for a COPD exacerbation, a patient-tailored physical activity program based on a motivational interview and the use of pedometers, with progressive and customized targets, improved the number of steps/day.Sociedad Española de Neumología y Cirugía Torácica (SEPAR), Grant/Award Number: 125-2015; Fundació Catalana de Pneumolgia (FUCAP), Grant/Award Number: SILVIA2017-202
Development of Potent Cellular and Humoral Immune Responses in Long-Term Hemodialysis Patients After 1273-mRNA SARS-CoV-2 Vaccination
Long-term hemodialysis (HD) patients are considered vulnerable and at high-risk of developing severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection due to their immunocompromised condition. Since COVID-19 associated mortality rates are higher in HD patients, vaccination is critical to protect them. The response towards vaccination against COVID-19 in HD patients is still uncertain and, in particular the cellular immune response is not fully understood. We monitored the humoral and cellular immune responses by analysis of the serological responses and Spike-specific cellular immunity in COVID-19-recovered and naïve HD patients in a longitudinal study shortly after vaccination to determine the protective effects of 1273-mRNA vaccination against SARS-CoV-2 in these high-risk patients. In naïve HD patients, the cellular immune response measured by IL-2 and IFN-ɣ secretion needed a second vaccine dose to significantly increase, with a similar pattern for the humoral response. In contrast, COVID-19 recovered HD patients developed a potent and rapid cellular and humoral immune response after the first vaccine dose. Interestingly, when comparing COVID-19 recovered healthy volunteers (HV), previously vaccinated with BNT162b2 vaccine to HD patients vaccinated with 1273-mRNA, these exhibited a more robust immune response that is maintained longitudinally. Our results indicate that HD patients develop strong cellular and humoral immune responses to 1273-mRNA vaccination and argue in favor of personalized immune monitoring studies in HD patients, especially if COVID-19 pre-exposed, to adapt COVID-19 vaccination protocols for this immunocompromised population.Funding was obtained from Instituto de Salud Carlos III (ISCIII) RICORS program to RICORS2040 (RD21/0005/0001), FEDER funds; Acción Estratégica en Salud Intramural (AESI), Instituto de Salud Carlos III, grant number AESI PI21CIII_00022 to PP and Healthstar-plus -REACT-UE Grant through Segovia Arana Research Institute Puerta de Hierro Majadahonda-IDIPHIM. JO is a member of VACCELERATE (European Corona Vaccine Trial Accelerator Platform) Network, which aims to facilitate and accelerate the design and implementation of COVID-19 phase 2 and 3 vaccine trials. JO is a member of the INsTRuCT under the MSC grant agreement Nº860003 (Innovative Training in Myeloid Regulatory Cell Therapy) Consortium, a network of European scientists from academia and industry focused on developing innovative immunotherapies.S
Clinical characteristics and respiratory care in hospitalized vaccinated SARS-CoV-2 patients
Background: The main objective of the present study was to analyze both clinical characteristics and evolution during hospitalization of a cohort of patients admitted for COVID-19 pneumonia who were not vaccinated, or with a complete or incomplete vaccination schedule. Methods: This COVID-19 specialized single-center cohort study of 1888 COVID-19 patients hospitalized at the “Enfermera Isabel Zendal” Emergencies Hospital (HEEIZ), Madrid (Spain) was performed between July 1 and September 30, 2021. It compared the results of 1327 hospitalized unvaccinated patients to 209 hospitalized fully vaccinated and 352 hospitalized partially vaccinated patients. The four different COVID-19 vaccines authorized in Spain during the time-period studied were: BNT162b2 (Pfizer); ChAdOx1 nCoV-19 (AstraZeneca), mRNA-1273 (Moderna); Ad26.COV2.S (Janssen). Findings: Hospitalized patients’ median age was 41 years (IQR 33–50) for the unvaccinated and 61 years (IQR 53–67) for the fully vaccinated ones. The main comorbidities were obesity, hypertension and diabetes mellitus. 20% of unvaccinated patients (266) required noninvasive respiratory care, as did 14% (51) of partially and 14% (30) of fully vaccinated; 6% (78) of the unvaccinated patients also needed invasive respiratory care, as did 5% (16) of partially and 11 (5%) fully vaccinated. Interpretation: Fully vaccinated patients were 84% (95% CI: 82–86%) less likely to be admitted to hospital, and protection rose for those aged <50 years. Once hospitalized, vaccinated patients displayed more protection against requiring respiratory care than unvaccinated ones, despite being older and having more comorbidities. No differences appeared for the four studied COVID-19 vaccines and complying with vaccination recommendations proved relevant. Funding: The research was funded by the “Plan Propio de Investigación” Program of the Castilla-La Mancha University /European Regional Development Fund (2021-GRIN-31,039
Increased COVID-19 mortality in people with previous cerebrovascular disease: a population-based cohort study
Coronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Ictus hemorràgic; Ictus isquèmic; Hemorràgia subaracnoideaCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Ictus hemorrágico; Ictus isquémico; Hemorragia subaracnoideaCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Hemorrhagic stroke; Ischemic stroke; Subarachnoid hemorrhageBackground: The aim of the study was to determine the association between previous stroke and mortality after coronavirus disease 2019 (COVID-19) according to sex, age groups, and stroke subtypes.
Methods: Prospective population-based cohort study including all COVID-19 positive cases between February 1 and July 31, 2020. Comorbidities and mortality were extracted using linked health administration databases. Previous stroke included transient ischemic attack, ischemic stroke, hemorrhagic stroke, spontaneous subarachnoid hemorrhage, and combined stroke for cases with more than one category. Other comorbidities were obesity, diabetes, hypertension, ischemic heart disease, atrial fibrillation, heart failure, chronic obstructive pulmonary disease, chronic kidney disease, cirrhosis, dementia, individual socioeconomic index, and deprivation index. Cases were followed up until December 31, 2020. Primary outcome was mortality of any cause after COVID-19 positivity. Cox proportional regression analysis adjusted for comorbidities was used. Stratified analyses were performed for sex and age (<60, 60-79, and ≥80 years).
Results: There were 91 629 COVID-19 cases. Previous strokes were 5752 (6.27%), of which 3887 (67.57%) were ischemic, 1237 (21.50%) transient ischemic attack, 255 (4.43%) combined, 203 (3.53%) hemorrhagic, and 170 (2.96%) subarachnoid hemorrhage. There were 9512 deaths (10.38%). Mortality was associated with previous stroke (hazard ratio [HR]=1.12 [95% CI, 1.06-1.18]; P<0.001), in both sexes separately (men=1.13 [1.05-1.22]; P=0.001; women=1.09 [1.01-1.18]; P=0.023), in people <60 years (HR=2.97 [1.97-4.48]; P<0.001) and 60 to 79 years (HR=1.32 [1.19-1.48]; P<0.001) but not in people ≥80 years (HR=1.02 [0.96-1.09]; P=0.437). Ischemic (HR=1.11 [1.05-1.18]; P=0.001), hemorrhagic (HR=1.53 [1.20-1.96]; P=0.001) and combined (HR=1.31 [1.05-1.63]; P=0.016) strokes were associated but not transient ischemic attack. Subarachnoid hemorrhage was associated only in people <60 years (HR=5.73 [1.82-18.06]; P=0.003).
Conclusions: Previous stroke was associated with a higher mortality in people younger than 80 years. The association occurred for both ischemic and hemorrhagic stroke but not for transient ischemic attack. These data might help healthcare authorities to establish prioritization strategies for COVID-19 vaccination.This work was supported, in part, by Spain’s Ministry of Health (Instituto de Salud Carlos III FEDER, RD16/0019/0002 and RD16/0019/0010 INVICTUS-PLUS
Differential effects of the second SARS-CoV-2 mRNA vaccine dose on T cell immunity in naive and COVID-19 recovered individuals
The rapid development of mRNA-based vaccines against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led to the design of accelerated vaccination schedules that have been extremely effective in naive individuals. While a two-dose immunization regimen with the BNT162b2 vaccine has been demonstrated to provide a 95% efficacy in naive individuals, the effects of the second vaccine dose in individuals who have previously recovered from natural SARS-CoV-2 infection has not been investigated in detail. In this study, we characterize SARS-CoV-2 spike-specific humoral and cellular immunity in naive and previously infected individuals during and after two doses of BNT162b2 vaccination. Our results demonstrate that, while the second dose increases both the humoral and cellular immunity in naive individuals, COVID-19 recovered individuals reach their peak of immunity after the first dose. These results suggests that a second dose, according to the current standard regimen of vaccination, may be not necessary in individuals previously infected with SARS-CoV-2.Funding: Research reported in this publication was supported in part by the National Cancer Institute of the NIH (5R01HD102614-02; R01CA249204 and R01CA248984) and an ISMMS seed fund to E.G. The authors gratefully acknowledge use of the services and facilities of the Tisch Cancer Institute supported by a NCI Cancer Center Support Grant (P30 CA196521). M.S. was supported by a NCI training grant (T32CA078207). This work was supported by an ISMMS seed fund to J.O.; Instituto de Salud Carlos III (COV20-00668) to R.C.R.; the Instituto de Salud Carlos III, Spanish Ministry of Science and Innovation (COVID-19 research call COV20/00181) co-financed by the European Development Regional Fund ‘‘A way to achieve Europe’’ to E.P.; the Instituto de Salud Carlos III, Spain (COV20/00170); the Government of Cantabria, Spain (2020UIC22-PUB-0019) to M.L.H.; the Instituto de Salud Carlos III (PI16CIII/00012) to P.P.; the Fondo Social Europeo e Iniciativa de Empleo Juvenil YEI (Grant PEJ2018-004557-A) to M.P.E.; and by REDInREN 016/009/009 ISCIII. This project has received funding from the European Union Horizon 2020 research and innovation programs VACCELERATE and INsTRuCT under grant agreements 101037867 and 860003
- …