25 research outputs found
Two Distinct Phases of Bilayer Graphene Films on Ru(0001)
By combining angle-resolved photoemission spectroscopy and scanning tunneling
microscopy we reveal the structural and electronic properties of multilayer
graphene on Ru(0001). We prove that large ethylene exposure allows to
synthesize two distinct phases of bilayer graphene with different properties.
The first phase has Bernal AB stacking with respect to the first graphene
layer, displays weak vertical interaction and electron doping. The long-range
ordered moir\'e pattern modulates the crystal potential and induces replicas of
the Dirac cone and minigaps. The second phase has AA stacking sequence with
respect to the first layer, displays weak structural and electronic modulation
and p-doping. The linearly dispersing Dirac state reveals the
nearly-freestanding character of this novel second layer phase
Metastable polymorphic phases in monolayer TaTe2
Polymorphic phases and collective phenomenaâsuch as charge density waves (CDWs)âin transition metal dichalcogenides (TMDs) dictate the physical and electronic properties of the material. Most TMDs naturally occur in a single given phase, but the fine-tuning of growth conditions via methods such as molecular beam epitaxy (MBE) allows to unlock otherwise inaccessible polymorphic structures. Exploring and understanding the morphological and electronic properties of new phases of TMDs is an essential step to enable their exploitation in technological applications. Here, scanning tunneling microscopy (STM) is used to map MBE-grown monolayer (ML) TaTe2. This work reports the first observation of the 1H polymorphic phase, coexisting with the 1T, and demonstrates that their relative coverage can be controlled by adjusting synthesis parameters. Several superperiodic structures, compatible with CDWs, are observed to coexist on the 1T phase. Finally, this work provides theoretical insight on the delicate balance between TeâŠTe and TaâTa interactions that dictates the stability of the different phases. The findings demonstrate that TaTe2 is an ideal platform to investigate competing interactions, and indicate that accurate tuning of growth conditions is key to accessing metastable states in TMD
Tratamiento quirĂșrgico de la miocardiopatĂa hipertrĂłfica obstructiva mediante la tĂ©cnica de Konno modificada
ResumenObjetivoMostrar la eficacia, seguridad y reproducibilidad de la tĂ©cnica de Konno modificada en la resoluciĂłn de la miocardiopatĂa hipertrĂłfica obstructiva.MĂ©todosCuatro casos de miocardiopatĂa hipertrĂłfica obstructiva, con edades de 8â59 años, 3 mujeres y 1 varĂłn, clĂnica de angina, disnea y presĂncopes. Gradiente mĂĄximo de 65â120 mmHg. Todos presentaban movimiento sistĂłlico anterior de la vĂĄlvula mitral e insuficiencia mitral, y fueron intervenidos con tĂ©cnica de Konno modificada.ResultadosTodos sobrevivieron. El gradiente preoperatorio descendiĂł un 91%. Tres casos quedaron con insuficiencia mitral ligera, todos pasaron a grado funcional I. Ănica complicaciĂłn: necesidad de marcapasos definitivo en un caso. Seguimiento medio de 54 meses.ConclusionesEsta tĂ©cnica cambia la resecciĂłn septal de Morrow por la ampliaciĂłn del tracto de salida del ventrĂculo izquierdo. Se ha mostrado eficaz y segura, con resultados estables.AbstractBackgroundThe efficacy, safety and feasibility of the modified Konno procedure for the surgical correction of hypertrophic obstructive cardiomyopathy (HOCM) are demonstrated.MethodsFour patients underwent a modified Konno procedure. The ages ranged from 8 to 59 years. There were three females and one male. Symptoms referred to were angina, dyspnea and presyncope. The echocardiography study revealed a maximum gradient between 65â120mm Hg. Systolic anterior motion of mitral valve and mitral regurgitation was present in all cases.ResultsThere were no in-hospital deaths. The gradients decreased by 91%. Mild postoperative mitral regurgitation was present in three patients. One permanent pacemaker was implanted. Mean follow up was 54 months.ConclusionsThis procedure is an alternative to the Morrows septal myectomy for the correction of HOCM, allowing a greater enlargement of the left ventricular outflow tract. It can be performed with good early and mid-term results proving to be safe and feasible
Atomic-scale study of type-II Dirac semimetal PtTe2 surface
Dirac semimetals (DSM) host linear bulk bands and topologically protected surface states, giving rise to exotic and robust properties. Platinum ditelluride (PtTe2) belongs to this interesting group of topological materials. Here, we employ scanning tunneling microscopy (STM) in combination with first-principles calculations to visualize and identify the native defects at the surface of a freshly cleaved PtTe2 crystal. Around these defects, short-wavelength electron density oscillations are observed. Fourier transform analysis of the energy-dependent quasiparticle interference patterns is in good agreement with our calculated joint density of states, demonstrating the singular properties of the surface of this type-II DSM. Our results evidence the power of STM in understanding the surface of topological material
Thermally activated processes for ferromagnet intercalation in graphene-heavy metal interfaces
The development of graphene (Gr) spintronics requires the ability to engineer epitaxial Gr heterostructures with interfaces of high quality, in which the intrinsic properties of Gr are modified through proximity with a ferromagnet to allow for efficient room temperature spin manipulation or the stabilization of new magnetic textures. These heterostructures can be prepared in a controlled way by intercalation through graphene of different metals. Using photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), we achieve a nanoscale control of thermally activated intercalation of a homogeneous ferromagnetic (FM) layer underneath epitaxial Gr grown onto (111)-oriented heavy metal (HM) buffers deposited, in turn, onto insulating oxide surfaces. XPS and STM demonstrate that Co atoms evaporated on top of Gr arrange in 3D clusters and, upon thermal annealing, penetrate through and diffuse below Gr in a 2D fashion. The complete intercalation of the metal occurs at specific temperatures, depending on the type of metallic buffer. The activation energy and the optimum temperature for the intercalation processes are determined. We describe a reliable method to fabricate and characterize in situ high-quality Gr-FM/HM heterostructures, enabling the realization of novel spin-orbitronic devices that exploit the extraordinary properties of GrThis research was supported by the Regional Government of Madrid through projects P2018/NMT-4321 (NANOMAGCOST-CM) and P2018/NMT-4511 (NMAT2D) and by the Spanish Ministry of Economy and Competitiveness (MINECO) through projects RTI2018-097895-B-C42, FIS2016-78591-C3-1-R, PGC2018-098613-B-C21, PGC2018-093291-B-I00, FIS2015-67367-C2-1-P, and PCIN-2015-111 (FLAGERA JTC2015 Graphene Flagship âSOgraphâ). IFIMAC acknowledges support from the âłMaria de Maeztuâł programme for units of Excellence in R&D (MDM-2014-0377). IMDEA Nanoscience is supported by the âSevero Ochoaâ programme for the Centres of Excellence in R&D, MINECO (grant number SEV-2016-0686
Getting the invite list right : a discussion of sepsis severity scoring systems in severe complicated intra-abdominal sepsis and randomized trial inclusion criteria
Background: Severe complicated intra-abdominal sepsis (SCIAS) is a worldwide challenge with increasing incidence. Open abdomen management with enhanced clearance of fluid and biomediators from the peritoneum is a potential therapy requiring prospective evaluation. Given the complexity of powering multi-center trials, it is essential to recruit an inception cohort sick enough to benefit from the intervention; otherwise, no effect of a potentially beneficial therapy may be apparent An evaluation of abilities of recognized predictive systems to recognize SCIAS patients was conducted using an existing intra-abdominal sepsis (IAS) database. Methods: All consecutive adult patients with a diffuse secondary peritonitis between 2012 and 2013 were collected from a quaternary care hospital in Finland, excluding appendicitis/cholecystitis. From this retrospectively collected database, a target population (93) of those with either ICU admission or mortality were selected. The performance metrics of the Third Consensus Definitions for Sepsis and Septic Shock based on both SOFA and quick SOFA, the World Society of Emergency Surgery Sepsis Severity Score (WSESSSS), the APACHE II score, Manheim Peritonitis Index (MPI), and the Calgary Predisposition, Infection, Response, and Organ dysfunction (CPIRO) score were all tested for their discriminant ability to identify this subgroup with SCIAS and to predict mortality. Results: Predictive systems with an area under-the-receiving-operating characteristic (AUQ curve >= 0.8 included SOFA, Sepsis-3 definitions, APACHE II, WSESSSS, and CPIRO scores with the overall best for CPIRO. The highest identification rates were SOFA score >= 2 (78.4%), followed by the WSESSSS score >= 8 (73.1%), SOFA >= 3 (752%), and APACHE II >= 14 (68.8%) identification. Combining the Sepsis-3 septic-shock definition and WSESSS >= 8 increased detection to 80%. Including CPIRO score >= 3 increased this to 82.8% (Sensitivity-SN; 83% Specificity-SP; 74%. Comparatively, SOFA >= 4 and WSESSSS >= 8 with or without septic-shock had 83.9% detection (SN; 84%, SP; 75%, 25% mortality). Conclusions: No one scoring system behaves perfectly, and all are largely dominated by organ dysfunction. Utilizing combinations of SOFA, CPIRO, and WSESSSS scores in addition to the Sepsis-3 septic shock definition appears to offer the widest "inclusion-criteria" to recognize patients with a high chance of mortality and ICU admission.Peer reviewe
Closed Or Open after Source Control Laparotomy for Severe Complicated Intra-Abdominal Sepsis (the COOL trial) : study protocol for a randomized controlled trial
Abstract
Background
Severe complicated intra-abdominal sepsis (SCIAS) has an increasing incidence with mortality rates over 80% in some settings. Mortality typically results from disruption of the gastrointestinal tract, progressive and self-perpetuating bio-mediator generation, systemic inflammation, and multiple organ failure. Principles of treatment include early antibiotic administration and operative source control. A further therapeutic option may be open abdomen (OA) management with active negative peritoneal pressure therapy (ANPPT) to remove inflammatory ascites and ameliorate the systemic damage from SCIAS. Although there is now a biologic rationale for such an intervention as well as non-standardized and erratic clinical utilization, this remains a novel therapy with potential side effects and clinical equipoise.
Methods
The Closed Or Open after Laparotomy (COOL) study will constitute a prospective randomized controlled trial that will randomly allocate eligible surgical patients intra-operatively to either formal closure of the fascia or use of the OA with application of an ANPTT dressing. Patients will be eligible if they have free uncontained intra-peritoneal contamination and physiologic derangements exemplified by septic shock OR a Predisposition-Infection-Response-Organ Dysfunction Score â„â3 or a World-Society-of-Emergency-Surgery-Sepsis-Severity-Score â„â8. The primary outcome will be 90-day survival. Secondary outcomes will be logistical, physiologic, safety, bio-mediators, microbiological, quality of life, and health-care costs. Secondary outcomes will include days free of ICU, ventilation, renal replacement therapy, and hospital at 30Â days from the index laparotomy. Physiologic secondary outcomes will include changes in intensive care unit illness severity scores after laparotomy. Bio-mediator outcomes for participating centers will involve measurement of interleukin (IL)-6 and IL-10, procalcitonin, activated protein C (APC), high-mobility group box protein-1, complement factors, and mitochondrial DNA. Economic outcomes will comprise standard costing for utilization of health-care resources.
Discussion
Although facial closure after SCIAS is considered the current standard of care, many reports are suggesting that OA management may improve outcomes in these patients. This trial will be powered to demonstrate a mortality difference in this highly lethal and morbid condition to ensure critically ill patients are receiving the best care possible and not being harmed by inappropriate therapies based on opinion only.
Trial registration
ClinicalTrials.gov
,
NCT03163095
Childrenâs and adolescentsâ rising animal-source food intakes in 1990â2018 were impacted by age, region, parental education and urbanicity
Animal-source foods (ASF) provide nutrition for children and adolescentsâ physical and cognitive development. Here, we use data from the Global Dietary Database and Bayesian hierarchical models to quantify global, regional and national ASF intakes between 1990 and 2018 by age group across 185 countries, representing 93% of the worldâs child population. Mean ASF intake was 1.9 servings per day, representing 16% of children consuming at least three daily servings. Intake was similar between boys and girls, but higher among urban children with educated parents. Consumption varied by age from 0.6 at <1 year to 2.5 servings per day at 15â19 years. Between 1990 and 2018, mean ASF intake increased by 0.5 servings per week, with increases in all regions except sub-Saharan Africa. In 2018, total ASF consumption was highest in Russia, Brazil, Mexico and Turkey, and lowest in Uganda, India, Kenya and Bangladesh. These findings can inform policy to address malnutrition through targeted ASF consumption programmes.publishedVersio
Incident type 2 diabetes attributable to suboptimal diet in 184 countries
The global burden of diet-attributable type 2 diabetes (T2D) is not well established. This risk assessment model estimated T2D incidence among adults attributable to direct and body weight-mediated effects of 11 dietary factors in 184 countries in 1990 and 2018. In 2018, suboptimal intake of these dietary factors was estimated to be attributable to 14.1 million (95% uncertainty interval (UI), 13.8â14.4 million) incident T2D cases, representing 70.3% (68.8â71.8%) of new cases globally. Largest T2D burdens were attributable to insufficient whole-grain intake (26.1% (25.0â27.1%)), excess refined rice and wheat intake (24.6% (22.3â27.2%)) and excess processed meat intake (20.3% (18.3â23.5%)). Across regions, highest proportional burdens were in central and eastern Europe and central Asia (85.6% (83.4â87.7%)) and Latin America and the Caribbean (81.8% (80.1â83.4%)); and lowest proportional burdens were in South Asia (55.4% (52.1â60.7%)). Proportions of diet-attributable T2D were generally larger in men than in women and were inversely correlated with age. Diet-attributable T2D was generally larger among urban versus rural residents and higher versus lower educated individuals, except in high-income countries, central and eastern Europe and central Asia, where burdens were larger in rural residents and in lower educated individuals. Compared with 1990, global diet-attributable T2D increased by 2.6 absolute percentage points (8.6 million more cases) in 2018, with variation in these trends by world region and dietary factor. These findings inform nutritional priorities and clinical and public health planning to improve dietary quality and reduce T2D globally.publishedVersio