Stability and Reversible Oxidation of Sub-Nanometric Cu5 Metal Clusters: Integrated Experimental Study and Theoretical Modeling**

Sub-nanometer metal clusters have special physical and chemical properties, significantly different from those of nanoparticles. However, there is a major concern about their thermal stability and susceptibility to oxidation. In situ X-ray Absorption spectroscopy and Near Ambient Pressure X-ray Photoelectron spectroscopy results reveal that supported Cu5 clusters are resistant to irreversible oxidation at least up to 773 K, even in the presence of 0.15 mbar of oxygen. These experimental findings can be formally described by a theoretical model which combines dispersion-corrected DFT and first principles thermochemistry revealing that most of the adsorbed O2 molecules are transformed into superoxo and peroxo species by an interplay of collective charge transfer within the network of Cu atoms and large amplitude “breathing” motions. A chemical phase diagram for Cu oxidation states of the Cu5-oxygen system is presented, clearly different from the already known bulk and nano-structured chemistry of Cu

Effect of Fe additive on the hydrogenation-dehydrogenation properties of 2LiH + MgB2/2LiBH4 + MgH2 system

Lithium reactive hydride composite 2LiBH4 + MgH2 (Li-RHC) has been lately investigated owing to its potential as hydrogen storage medium for mobile applications. However, the main problem associated with this material is its sluggish kinetic behavior. Thus, aiming to improve the kinetic properties, in the present work the effect of the addition of Fe to Li-RHC is investigated. The addition of Fe lowers the starting decomposition temperature of Li-RHC about 30 °C and leads to a considerably faster isothermal dehydrogenation rate during the first hydrogen sorption cycle. Upon hydrogenation, MgH2 and LiBH4 are formed whereas Fe appears not to take part in any reaction. Upon the first dehydrogenation, the formation of nanocrystalline, well distributed FeB reduces the overall hydrogen storage capacity of the system. Throughout cycling, the agglomeration of FeB particles causes a kinetic deterioration. An analysis of the hydrogen kinetic mechanism during cycling shows that the hydrogenation and dehydrogenation behavior is influenced by the activity of FeB as heterogeneous nucleation center for MgB2 and its non-homogenous distribution in the Li-RHC matrix.Fil: Puszkiel, Julián Atilio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh;Fil: Gennari, Fabiana Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro Atómico Bariloche; ArgentinaFil: Arneodo Larochette, Pierre Paul. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro Atómico Bariloche; ArgentinaFil: Ramallo Lopez, Jose Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Vainio, U.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh; . Deutsches Elektronen-Synchrotron; AlemaniaFil: Karimi, F.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh;Fil: Pranzas, P. K.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh;Fil: Troiani, Horacio Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro Atómico Bariloche; ArgentinaFil: Pistidda, C.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh;Fil: Jepsen, J.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh;Fil: Tolkiehn, M.. Deutsches Elektronen-Synchrotron; AlemaniaFil: Welter, E.. Deutsches Elektronen-Synchrotron; AlemaniaFil: Klassen, T.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh;Fil: Bellosta Von Colbe, J.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh;Fil: Dornheim, M.. Helmholtz-zentrum Geesthacht - Zentrum Für Material- Und Küstenforschung Gmbh

Atomic force microscopy analysis of nanoparticles in non-ideal conditions

Nanoparticles are often measured using atomic force microscopy or other scanning probe microscopy methods. For isolated nanoparticles on flat substrates, this is a relatively easy task. However, in real situations, we often need to analyze nanoparticles on rough substrates or nanoparticles that are not isolated. In this article, we present a simple model for realistic simulations of nanoparticle deposition and we employ this model for modeling nanoparticles on rough substrates. Different modeling conditions (coverage, relaxation after deposition) and convolution with different tip shapes are used to obtain a wide spectrum of virtual AFM nanoparticle images similar to those known from practice. Statistical parameters of nanoparticles are then analyzed using different data processing algorithms in order to show their systematic errors and to estimate uncertainties for atomic force microscopy analysis of nanoparticles under non-ideal conditions. It is shown that the elimination of user influence on the data processing algorithm is a key step for obtaining accurate results while analyzing nanoparticles measured in non-ideal conditions

Mortality and pulmonary complications in patients undergoing surgery with perioperative sars-cov-2 infection: An international cohort study

Background The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (740%) had emergency surgery and 280 (248%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (261%) patients. 30-day mortality was 238% (268 of 1128). Pulmonary complications occurred in 577 (512%) of 1128 patients; 30-day mortality in these patients was 380% (219 of 577), accounting for 817% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 175 [95% CI 128-240], p<00001), age 70 years or older versus younger than 70 years (230 [165-322], p<00001), American Society of Anesthesiologists grades 3-5 versus grades 1-2 (235 [157-353], p<00001), malignant versus benign or obstetric diagnosis (155 [101-239], p=0046), emergency versus elective surgery (167 [106-263], p=0026), and major versus minor surgery (152 [101-231], p=0047). Interpretation Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Efecto de las enfermedades de fin de ciclo en el crecimiento de distintos genotipos de soja relacionado a la fecha de siembra

El objetivo de este trabajo fue evaluar la influencia de las enfermedades de fin de ciclo (EFC) en distintos genotipos de soja en cuatro fechas de siembra (FS), considerando la duración del área foliar sana. Los parámetros evaluados fueron: severidad,área bajo la curva de progreso de las enfermedades de fin de ciclo (ACPE) y duración del área foliar sana (DAFS). Las curvas de progreso se iniciaron (35 dds) con valores de severidad, durante la 1 FS, del orden de 2,0 al 11,7%,y de 1,7 a 7,8% en las campañas 2000/01 y 2001/02, respectivamente, y alcanzaron valores máximos (75 dds) desde 25,0% a 42,3% en la primera campaña yde 16,3 % a 41,7% en la siguiente. El padrón de las curvas de progreso y la interacción entre FS y genotipo permitieron concluir que: 1- retrasando la fecha de siembra se disminuyó el riesgo de niveles altos de EFC; 2- la interacción para ACPE entre genotipo y FS indicó que es muy difícil separar el efecto del ambiente del genotipo; 3- el complejo de enfermedades de fin de ciclo de la soja afectó la duración del área foliar sana, lo que se reflejó en una disminución promedio de crecimiento de 27% en la campaña 2000/01 y de 31% en la siguiente

Stable isotope analysis and differences in diet and social status in northern Medieval Christian Spain (9th–13th centuries CE)

The Iberian Peninsula was at the forefront of the religious, economic, and political changes that swept across Europe during the Medieval Period, including the expansion of Christianity following the disintegration of the Umayyad Caliphate. Between the 9th and the 13th centuries CE, northern Iberia, in particular, witnessed a marked demographic and economic expansion that accompanied the emergence and development of different Christian Kingdoms. A growth in religious infrastructure driven by territorial expansion at the expense of Al-Andalus, and the emerging importance of the Camino de Santiago (the Way of St. James) from the 11th century CE, represented vital processes in changing urban networks and social stratification. However, shifting diets and social structures brought about by these changes require direct study beyond historical texts or localised osteoarchaeological and biomolecular studies in order to determine their wider impacts on peoples’ lived experience. Here, we apply radiocarbon dating (n = 6) and stable carbon and nitrogen isotope analysis to bone and dentine collagen from various locations (n = 10) across the north and north-eastern areas of modern Spain, where three prominent Medieval Christian Kingdoms (Aragon, Castille and Navarre) developed. We sampled 40 human and 32 faunal remains dating to between the 9th and 13th centuries CE, including historical personages such as Sancho Ramirez, Count of Ribagorza and an illegitimate son of King Ramiro I of Aragon; Saint Raymond William or San Ramón de Roda; Pedro de Librana, the first bishop of the city of Zaragoza after its conquest by the Christians in the 12th century CE; an unknown princess from the royal house of Aragon; and individuals from the urban and rural nuclei of Pamplona, Logroño, Lobera de Onsella (Zaragoza), and San Roque de las Quintanillas (Burgos). We compared our results to existing data from the same area demonstrating clear differences in access to animal protein and marine/freshwater resources between rural, urban, and high social status populations on a regional scale. Our data show significant differences in δ15N values between the different groups, with the highest values seen among the ‘elite’, followed by urban populations who benefited from trade and socio-economic diversity. This dataset acts as an important reference point for future studies focusing on changes in the diet and health among different sectors of Medieval society and, in particular, the development of social inequality in the Christian Kingdoms of Iberia as they formed at the centre of novel cultural and religious exchanges across Europe.. Introduction 2. Background 2.1. The urban and rural sites, social elites, and their archaeological and historical contexts 2.1.1. Archaeological sites 2.1.2. Abbey of San Pedro de Siresa, Huesca, Aragon (9th–10th centuries CE) 2.1.3. Social ‘elite’ personages 2.2. Historical insights into Medieval Iberian diets 2.3. Stable isotope analysis and dietary reconstruction in Medieval Europe 3. Materials and methods 3.1. Radiocarbon dating 3.2. δ13C and δ15N analysis of bone and dentine collagen 3.3. Statistical analysis 4. Results 4.1. Radiocarbon dating 4.2. Fauna δ13C and δ15N 4.3. Human δ13C and δ15N 5. Discussion 5.1. Diet and social status 5.2. Comparison with published data 6. Conclusio

Stable isotope analysis and differences in diet and social status in northern Medieval Christian Spain (9th–13th centuries CE)

The Iberian Peninsula was at the forefront of the religious, economic, and political changes that swept across Europe during the Medieval Period, including the expansion of Christianity following the disintegration of the Umayyad Caliphate. Between the 9th and the 13th centuries CE, northern Iberia, in particular, witnessed a marked demographic and economic expansion that accompanied the emergence and development of different Christian Kingdoms. A growth in religious infrastructure driven by territorial expansion at the expense of Al-Andalus, and the emerging importance of the Camino de Santiago (the Way of St. James) from the 11th century CE, represented vital processes in changing urban networks and social stratification. However, shifting diets and social structures brought about by these changes require direct study beyond historical texts or localised osteoarchaeological and biomolecular studies in order to determine their wider impacts on peoples’ lived experience. Here, we apply radiocarbon dating (n = 6) and stable carbon and nitrogen isotope analysis to bone and dentine collagen from various locations (n = 10) across the north and north-eastern areas of modern Spain, where three prominent Medieval Christian Kingdoms (Aragon, Castille and Navarre) developed. We sampled 40 human and 32 faunal remains dating to between the 9th and 13th centuries CE, including historical personages such as Sancho Ramirez, Count of Ribagorza and an illegitimate son of King Ramiro I of Aragon; Saint Raymond William or San Ramón de Roda; Pedro de Librana, the first bishop of the city of Zaragoza after its conquest by the Christians in the 12th century CE; an unknown princess from the royal house of Aragon; and individuals from the urban and rural nuclei of Pamplona, Logroño, Lobera de Onsella (Zaragoza), and San Roque de las Quintanillas (Burgos). We compared our results to existing data from the same area demonstrating clear differences in access to animal protein and marine/freshwater resources between rural, urban, and high social status populations on a regional scale. Our data show significant differences in δ15N values between the different groups, with the highest values seen among the ‘elite’, followed by urban populations who benefited from trade and socio-economic diversity. This dataset acts as an important reference point for future studies focusing on changes in the diet and health among different sectors of Medieval society and, in particular, the development of social inequality in the Christian Kingdoms of Iberia as they formed at the centre of novel cultural and religious exchanges across Europe

Synthesis of water-soluble gold clusters in nanosomes displaying robust photoluminescence with very large Stokes shift

This paper reports a novel procedure using nanosomes, made of bola-hydroxyl and mercapto-palmitic acids, for the production of gold clusters with robust luminescent emissions and very large Stokes shifts. It shows that these results cannot be explained by the currently accepted mechanism based on ligand-to-metal charge transfer absorptions involving electron-rich ligands attached to the cluster core. Exhaustive characterization of the cluster samples using Mass Spectrometry, HR-TEM/STEM, XPS, EXAFS, and steady-state and time-resolved luminescence allows to deduce that a mixture of two cluster sizes, having non-closed shell electronic configurations, are firstly generated inside the nanosome compartments due to the difference in bonding strength of the two types of terminal groups in the fatty acids. This initial bimodal cluster size distribution slowly evolves into very stable, closed-shell Au cluster complexes (Au6-Au16 and Au5-Au14) responsible for the observed luminescent properties. The very small (≈1.2 nm) synthesized cluster complexes are water soluble and suitable to be used for the conjugation of biomolecules (through the terminal COO− groups) making these systems very attractive as biomarkers and offering, at the same time, a novel general strategy of fabricating stable atom-level quantum dots with large Stokes shifts of great importance in many sensor applications.Fil: Santiago González, B.. Universidad de Santiago de Compostela; EspañaFil: Vázquez Vázquez, C.. Universidad de Santiago de Compostela; EspañaFil: Blanco Varela, M. C.. Universidad de Santiago de Compostela; EspañaFil: Gaspar Martinho, J. M.. Universidade de Lisboa; PortugalFil: Ramallo Lopez, Jose Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Requejo, Felix Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: López Quintela, M. A.. Universidad de Santiago de Compostela; Españ