Numerical modelling and experimental validation of dynamic fracture events along weak planes

The conceptual simplicity and the ability of cohesive finite element models to describe complex fracture phenomena makes them often the approach of choice to study dynamic fracture. These models have proven to reproduce some experimental features, but to this point, no systematic study has validated their predictive ability; the difficulty in producing a sufficiently complete experimental record, and the intensive computational requirements needed to obtain converged simulations are possible causes. Here, we present a systematic integrated numerical–experimental approach to the verification and validation (V&V) of simulations of dynamic fracture along weak planes. We describe the intertwined computational and the experimental sides of the work, present the V&V results, and extract general conclusions about this kind of integrative approach

Phlebotominae Sand Flies in Paraguay. Abundance Distribution in the Southeastern Region

From September 1993 to August 2001, 7,190 phlebotomine were collected with CDC light trap in an endemic area for human leishmaniasis, in the departments of Misiones and Itapúa, Paraguay. Eleven species were identified: Lutzomyia neivai (93.7%), L. whitmani (4.1%), and L. fischeri, L. shannoni, L. migonei, L. misionensis, L. cortelezzii, L. pessoai, L. alphabetica, Brumptomyia avellari and B. guimaraesi (less than 1%). The last three species are new records for the country. The biodiversity and phlebotomine abundance were associated with the proximity to primary forest or gallery forest, but L. neivai was also found in peridomestic periurban environment. L. neivai was found throughout the year, and showed a period of higher activity from September to April (spring to fall) with a unimodal or bimodal pattern in relation to the annual rainy peaks during the summer. Background literature about phlebotomine from Paraguay has been reviewed.Fil: Salomón, Oscar Daniel. Ministerio de Salud de la Nación; ArgentinaFil: Rossi, Gustavo Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Cousiño, Blanca. Instituto de Investigaciones en Ciencias de la Salud; ParaguayFil: Spinelli, Gustavo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología ; ArgentinaFil: Rojas de Arias, Antonieta. Instituto de Investigaciones en Ciencias de la Salud; ParaguayFil: López de Puerto, Delfin G.. Instituto de Investigaciones en Ciencias de la Salud; ParaguayFil: Ortiz, Arnaldo J.. Instituto de Investigaciones en Ciencias de la Salud; Paragua

Simulating Physical Phenomena by Quantum Networks

Physical systems, characterized by an ensemble of interacting elementary constituents, can be represented and studied by different algebras of observables or operators. For example, a fully polarized electronic system can be investigated by means of the algebra generated by the usual fermionic creation and annihilation operators, or by using the algebra of Pauli (spin-1/2) operators. The correspondence between the two algebras is given by the Jordan-Wigner isomorphism. As we previously noted similar one-to-one mappings enable one to represent any physical system in a quantum computer. In this paper we evolve and exploit this fundamental concept in quantum information processing to simulate generic physical phenomena by quantum networks. We give quantum circuits useful for the efficient evaluation of the physical properties (e.g, spectrum of observables or relevant correlation functions) of an arbitrary system with Hamiltonian $H$.Comment: 44 pages, 15 psfigur

Factors influencing carbon stocks and accumulation rates in eelgrass meadows across New England, USA

Increasing the protection of coastal vegetated ecosystems has been suggested as one strategy to compensate for increasing carbon dioxide (CO2) in the atmosphere as the capacity of these habitats to sequester and store carbon exceeds that of terrestrial habitats. Seagrasses are a group of foundation species that grow in shallow coastal and estuarine systems and have an exceptional ability to sequester and store large quantities of carbon in biomass and, particularly, in sediments. However, carbon stocks (Corg stocks) and carbon accumulation rates (Corg accumulation) in seagrass meadows are highly variable both spatially and temporally, making it difficult to extrapolate this strategy to areas where information is lacking. In this study, Corg stocks and Corg accumulation were determined at 11 eelgrass meadows across New England, representing a range of eutrophication and exposure conditions. In addition, the environmental factors and structural characteristics of meadows related to variation in Corg stocks were identified. The objectives were accomplished by assessing stable isotopes of δ13C and δ15N as well as %C and %N in plant tissues and sediments, measuring grain size and 210Pb of sediment cores, and through assessing site exposure. Variability in Corg stocks in seagrass meadows is well predicted using commonly measured environmental variables such as grain size distribution. This study allows incorporation of data and insights for the northwest Atlantic, where few studies on carbon sequestration by seagrasses have been conducted

5-Fluorouracil-loaded poly(ε-caprolactone) nanoparticles combined with phage E gene therapy as a new strategy against colon cancer

This work aimed to develop a new therapeutic approach to increase the efficacy of 5-fluorouracil (5-FU) in the treatment of advanced or recurrent colon cancer. 5-FU-loaded biodegradable poly(ε-caprolactone) nanoparticles (PCL NPs) were combined with the cytotoxic suicide gene E (combined therapy). The SW480 human cancer cell line was used to assay the combined therapeutic strategy. This cell line was established from a primary adenocarcinoma of the colon and is characterized by an intrinsically high resistance to apoptosis that correlates with its resistance to 5-FU. 5-FU was absorbed into the matrix of the PCL NPs during synthesis using the interfacial polymer disposition method. The antitumor activity of gene E from the phage ϕX174 was tested by generating a stable clone (SW480/12/E). In addition, the localization of E protein and its activity in mitochondria were analyzed. We found that the incorporation of 5-FU into PCL NPs (which show no cytotoxicity alone), significantly improved the drug’s anticancer activity, reducing the proliferation rate of colon cancer cells by up to 40-fold when compared with the nonincorporated drug alone. Furthermore, E gene expression sensitized colon cancer cells to the cytotoxic action of the 5-FU-based nanomedicine. Our findings demonstrate that despite the inherent resistance of SW480 to apoptosis, E gene activity is mediated by an apoptotic phenomenon that includes modulation of caspase-9 and caspase-3 expression and intense mitochondrial damage. Finally, a strongly synergistic antiproliferative effect was observed in colon cancer cells when E gene expression was combined with the activity of the 5-FU-loaded PCL NPs, thereby indicating the potential therapeutic value of the combined therapy

Role of carbonate burial in Blue Carbon budgets

Calcium carbonates (CaCO3) often accumulate in mangrove and seagrass sediments. As CaCO3 production emits CO2, there is concern that this may partially offset the role of Blue Carbon ecosystems as CO2sinks through the burial of organic carbon (Corg). A global collection of data on inorganic carbon burial rates (Cinorg, 12% of CaCO3 mass) revealed global rates of 0.8 TgCinorg yr−1 and 15–62 TgCinorg yr−1 in mangrove and seagrass ecosystems, respectively. In seagrass, CaCO3burial may correspond to an offset of 30% of the net CO2 sequestration. However, a mass balance assessment highlights that the Cinorg burial is mainly supported by inputs from adjacent ecosystems rather than by local calcification, and that Blue Carbon ecosystems are sites of net CaCO3 dissolution. Hence, CaCO3 burial in Blue Carbon ecosystems contribute to seabed elevation and therefore buffers sea-level rise, without undermining their role as CO2 sinks

Airway stent complications: the role of follow-up bronchoscopy as a surveillance method.

Background: Airway stenting has become an integral part of the therapeutic endoscopic management of obstructive benign and malignant central airway diseases. Despite increased use of airway stents and frequent stent-associated complications, no clear guidelines for surveillance and maintenance exist. This study aim is to elucidate predictive factors associated with development of stent complications, as well as an optimal surveillance period for follow-up bronchoscopy for early detection and possible prevention of stent-associated complications. Methods: Retrospective cohort study of all patients who underwent airway stent placements at our institution from April 2010 to December 2013 for benign and malignant airway diseases. Metallic, silicone (straight, Y stent, T-tube) and hybrid stents were included in the study. Stent complications were analyzed at the time of follow-up bronchoscopy performed four to six weeks after initial stent placement or earlier if patients became symptomatic. Results: The study included 134 patients of which 147 stents were placed. Follow-up bronchoscopy was performed in 94 patients. Symptomatic status at the time of follow-up bronchoscopy was not associated with stent complications [odds ratio (OR) =1.88; 95% CI: 0.79-4.45; P=0.15]. Patient age, sex, indication for stent placement, and stent location, were not associated with development of complications (all P\u3e0.05). Compared to all other stents, hybrid stents were more likely to migrate (OR =6.60; 95% CI: 2.16-20.2; P=0.001) or obstruct by secretions (OR =2.53; 95% CI: 1.10-5.84; P=0.03). There were no complications associated with surveillance bronchoscopy. Conclusions: Surveillance bronchoscopy within 4 to 6 weeks of stent placement may be useful for early detection of complications and their subsequent management, regardless of symptomatic status and indication for stent placement. Prospective multicenter studies are needed to compare optimal surveillance methods and the impact on patient mortality, morbidity and healthcare costs

Electromagnetic navigation transthoracic needle aspiration for the diagnosis of pulmonary nodules: A safety and feasibility pilot study

BACKGROUND: Pulmonary nodules remain a diagnostic challenge for physicians. Minimally invasive biopsy methods include bronchoscopy and CT guided transthoracic needle aspiration (TTNA). A novel electromagnetic guidance transthoracic needle aspiration (ETTNA) procedure which can be combined with navigational bronchoscopy (NB) and endobronchial ultrasound (EBUS) in a single setting has become available. METHODS: A prospective pilot study examining the safety, feasibility and diagnostic yield of ETTNA in a single procedural setting. All patients enrolled underwent EBUS for lung cancer staging followed by NB and ETTNA. Feasibility of performing ETTNA and a safety assessment by recording procedural related complications including pneumothorax or bleeding was performed. Diagnostic yield of ETTNA defined by a definitive pathologic tissue diagnosis was recorded. An additional diagnostic yield analysis was performed using a cohort analysis of combined interventions (EBUS + NB + ETTNA). All non-diagnostic biopsies were either followed with radiographic imaging or a surgical biopsy was performed. RESULTS: Twenty-four subjects were enrolled. ETTNA was feasible in 96% of cases. No bleeding events occurred. There were five pneumothoraces (21%) of which only two (8%) subjects required drainage. The diagnostic yield for ETTNA alone was 83% and increased to 87% (P=0.0016) when ETTNA was combined with NB. When ETTNA and NB were performed with EBUS for complete staging, the diagnostic yield increased further to 92% (P=0.0001). CONCLUSIONS: This is the first human pilot study demonstrating an acceptable safety and feasibility profile with a novel ETTNA system. Further studies are needed to investigate the increased diagnostic yield from this pilot study

Reviews and syntheses: 210Pb-derived sediment and carbon accumulation rates in vegetated coastal ecosystems-setting the record straight

Vegetated coastal ecosystems, including tidal marshes, mangroves and seagrass meadows, are being increasingly assessed in terms of their potential for carbon dioxide sequestration worldwide. However, there is a paucity of studies that have effectively estimated the accumulation rates of sediment organic carbon (Corg), also termed blue carbon, beyond the mere quantification of Corg stocks. Here, we discuss the use of the 210Pb dating technique to determine the rate of Corg accumulation in these habitats. We review the most widely used 210Pb dating models to assess their limitations in these ecosystems, often composed of heterogeneous sediments with varying inputs of organic material, that are disturbed by natural and anthropogenic processes resulting in sediment mixing and changes in sedimentation rates or erosion. Through a range of simulations, we consider the most relevant processes that impact the 210Pb records in vegetated coastal ecosystems and evaluate how anomalies in 210Pb specific activity profiles affect sediment and Corg accumulation rates. Our results show that the discrepancy in sediment and derived Corg accumulation rates between anomalous and ideal 210Pb profiles is within 20% if the process causing such anomalies is well understood. While these discrepancies might be acceptable for the determination of mean sediment and Corg accumulation rates over the last century, they may not always provide a reliable geochronology or historical reconstruction. Reliable estimates of Corg accumulation rates might be difficult at sites with slow sedimentation, intense mixing and/or that are affected by multiple sedimentary processes. Additional tracers or geochemical, ecological or historical data need to be used to validate the 210Pbderived results. The framework provided in this study can be instrumental in reducing the uncertainties associated with estimates of Corg accumulation rates in vegetated coastal sediments.This work was funded by the CSIRO Flagship Marine & Coastal Carbon Biogeochemical Cluster (Coastal Carbon Cluster), the Spanish Ministry of Economy and Competitiveness (projects EstresX CTM2012-32603, MedShift CGL2015-71809-P), the Generalitat de Catalunya (MERS 2017 SGR – 1588), the Australian Research Council LIEF Project (LE170100219), the Edith Cowan University Faculty Research Grant Scheme and the King Abdullah University of Science and Technology (KAUST) through baseline funding to Carlos M. Duarte. This work contributes to the ICTA Unit of Excellence (MinECo, MDM2015-0552

Tratamiento doble con calcifediol asociado aparicalcitol y biomarcadores de riesgo cardiovascularen hemodiálisis

Introducción: El déficit de 25-hidroxivitamina D (25OHD) asociado a un hiperparatiroidismo secundario son hallazgos frecuentes en pacientes con enfermedad renal crónica (ERC) en hemodiálisis (HD). Estos hechos se asocian con un incremento de la morbimortalidad de origen cardiovascular (CV). Niveles séricos adecuados de 25OHD, así como el uso de activadores selectivos del receptor de vitamina D (AsRVD), han demostrado tener efectos beneficiosos sobre el metabolismo óseo-mineral y el riesgo CV de manera independiente. Actualmente aún existe controversia respecto al tipo de suplementación que precisan los pacientes con ERC en HD. Objetivo: El objetivo de nuestro estudio fue evaluar si existe beneficio alguno en el tratamiento combinado de 25OHD, calcifediol oral y AsRVD, paricalcitol oral sobre el metabolismo óseo-mineral y marcadores inflamatorios, respecto al tratamiento único con cada uno de ellos, en un grupo de pacientes de HD. Material y métodos: Realizamos un estudio prospectivo de 6 meses de duración sobre 26 pacientes de nuestra unidad en HD. Aleatorizamos a los pacientes en dos grupos; el grupo 1 (G1) recibió tratamiento con paricalcitol oral a dosis de 1 ?g/día. El grupo 2 (G2) fue tratado con calcifediol 1 ampolla/sem (0,266 mg/sem = 16.000 U) por vía oral. Trascurridos 3 meses de tratamiento, al G1 se le añadió calcifediol y al G2, paricalcitol a las mismas dosis, manteniendo dichos tratamientos durante 3 meses más, hasta completar los 6 meses de seguimiento. Las determinaciones analíticas se llevaron a cabo en los meses 0, 3 y 6, midiéndose en todos los pacientes los marcadores séricos de 25OHD, calcio, fósforo y hormona paratiroidea (PTH); como marcadores de remodelado óseo se midió la fosfatasa alcalina, propéptido aminoterminal del procolágeno tipo 1 (Pinp1) y el telopéptido carboxilo-terminal del colágeno tipo I (Cross Laps); marcadores inflamatorios (interleuquina 8 [IL-8]). Asimismo se recogieron datos de niveles de insulina, glucosa, hemoglobina, agentes eritropoyéticos (AEE) e índices de resistencia a la eritropoyetina y HOMA (homeostasis model assessment). Resultados: Se detecta un déficit de 25OHD en todos los pacientes a estudio, con una media de 13,67 ± 4,81 ng/ml. La suplementación con calcifediol oral aislado corrige este déficit sin evidencia de toxicidad (35,36 ± 33,68 ng/ml en el G1 a los 6 meses y 59,21 ± 26,50 ng/ml en el G2 a los 3 meses). El tratamiento con paricalcitol reduce de forma significativa los niveles de PTH en el G1 a los 3 meses (p < 0,039) no observándose esta significación, aunque sí descenso de la PTH, en el G2 tras su introducción a partir del tercer mes. Asimismo, observamos una disminución del marcador óseo Pinp1, con paricalcitol sin otros cambios, apuntando a un posible efecto directo sobre las células óseas (p < 0,001). Tanto el tratamiento con calcifediol como con paricalcitol producen una significativa disminución en los niveles de IL-8 (p < 0,001), conocido marcador inflamatorio, llamando la atención una tendencia a mejor respuesta a los AEE, en posible relación con este descenso de la inflamación. El índice HOMA no cambió de forma significativa. Conclusión: Con nuestros resultados, no podemos concluir que la asociación calcifediol-paricalcitol produzca ventajas sobre el efecto de cada uno de ellos por separado en los marcadores medidos. Paricalcitol además, por sí solo, parece tener efecto directo sobre la remodelación ósea.Background:The deficit of 25-hydroxyvitamin D (25OHD)associated with secondary hyperparathyroidism (SHPT) is afrequent finding in chronic kidney disease (CKD) patientson haemodialysis (HD). These events are associated withincreased morbidity and mortality rates of cardiovascular(CV) origin. Adequate 25OHD serum levels as well as theuse of selective vitamin D receptor activators (VDRA) havebeen shown to have beneficial and independent effects onbone mineral metabolism and cardiovascular risk.Currently, there is still controversy regarding the type ofsupplementation needed by CKD patients on HD.Objective:The aim of our study was to evaluate whetherthere is a benefit of combination therapy with 25OHD,calcifediol and a VDRA, oral paricalcitol, on bone-mineralmetabolism and inflammatory markers, compared tosingle treatment with each of these in a group of patientson HD.Material and method:We performed aprospective study of 6 months, involving 26 patients in ourHD unit. We randomised patients into two groups: group1 (G1) received oral paricalcitol treatment at doses of1mcg/day. Group 2 (G2) was treated with 1 ampoulecalcifediol/wk (0.266mg/wk=16 000U) orally. After 3months of treatment, calcifediol and paricalcitol wereadded to the G1 and G2 respectively at the same doses,keeping these treatments together for 3 months tocomplete the 6 months of follow-up. Laboratory tests were performed at months 0, 3 and 6, measuring in allpatients serum markers of 25OHD, calcium (Ca),phosphorus (P) and PTH. Bone turnover markers measuredwere: alkaline phosphatase (AP), aminoterminalpropeptide of procollagen type 1 (Pinp1) and carboxyl-terminal telopeptide of type I collagen (CrossLaps), andinflammatory markers: IL-8. We also collected data onlevels of insulin, glucose, haemoglobin, erythropoiesis-stimulating agents (ESAs) and rates of resistance to EPOand HOMA (homeostasis model assessment).Results:Wedetected a deficit of 25-hydroxyvitamin D in all patientsstudied, with a mean of 13.67±4.81ng/ml.Supplementation with oral calcifediol significantlycorrects this deficit without evidence of toxicity(35.36±33.68ng/ml in G1 at 6 months and59.21±26.50ng/ml in G2 at 3 months). Paricalcitoltreatment significantly reduces PTH levels in G1 at 3months (P<.039). We also noted a decrease in bone markerPinp1 with paricalcitol, pointing to a possible direct effecton bone cells (P<.001). Both treatment with paricalcitoland with calcifediol produced a significant decrease inlevels of IL-8 (P<.001), a known inflammatory marker,drawing attention to a trend towards better response toerythropoiesis-stimulating agents (ESAs), possibly relatedto the decrease in inflammation. The HOMA index did notchange significantly.Conclusion:Based on our results, wecannot conclude that the association of calcifediol andparicalcitol produces advantages over the effect of eachdrug separately. In addition, Paricalcitol by itself appearsto have a direct effect on cellular bone remodelling