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The porous-cracked microstructure of plasma sprayed ceramics coatings directly influences their macroscopic mechanical response. A 3D micromechanical model based on the discrete element method (DEM) is developed to reproduce their behavior. 3D observations are conducted with FIB-SEM nano-tomography and image analysis is used to extract and discretize the microstructure. A modeling strategy is developed to incorporate both pores and cracks into the model while preserving the computation performance. The lattice nature of DEM is used for the modeling of crack thickness that are smaller than the discrete element size. A method to compute the crack thickness from gray level images is proposed. Virtual quasi-static tests are performed on a sample of yttria-stabilized-zirconia. The results are in accordance with the literature data, such as the anisotropy and the non-linear behavior. The model is helpful to precisely investigate the role of the microscopic components, and micro-cracking on the macroscopic failure. • Crack thickeness is computed by image analysis and modeled in a numerical model. • Non-linear behavior in compression is due to crack closure with increasing pressure. • Cracks are responsible for transverse isotropy. • A coupling effect between pores and cracks is identified. • A DEM tensile failure criterion allows modelling macroscopic failure in compression. [ABSTRACT FROM AUTHOR]

Most of the scientific literature concerning former high-level athletes is devoted to their professional retraining. There are comparatively few empirical studies dealing with their body representations and practices. Based on Pierre Bourdieu's theoretical framework, this article presents the results of an interview survey with 30 former high-level athletes. It shows that their relationships with their bodies result from their specific body trajectories, marked by family socialization and social background, sports socialization, injuries, and the possession of different forms of capital. In contrast to mondains, who have relatively stable body trajectories, oblates are marked by less homogeneous socialization and see their body trajectories divided between a form of personal dissatisfaction on the one hand and a feeling of saturation with their sport on the other. [ABSTRACT FROM AUTHOR]

Introduction: Assessing bowel viability can be challenging during acute surgical procedures, especially regarding mesenteric ischaemia. Intraoperative fluorescence angiography (FA) may be a valuable tool for the surgeon to determine whether bowel resection is necessary and to define the most appropriate resection margins. The aim of this study is to report on FA use in the acute setting and to judge its impact on intraoperative decision making.Materials and Methods: This is a multi-centre, retrospective case series of patients undergoing emergency abdominal surgery between February 2016 and 2021 in three general/colorectal units where intraoperative FA was performed to assess bowel viability. Primary endpoint was change of management after the FA assessment.Results: A total of 93 patients (50 males, 66.6 ± 19.2 years, ASA score ≥ III in 85%) were identified and studied. Initial surgical approach was laparotomy in 66 (71%) patients and laparoscopy in 27 (29% and seven, 26% conversions). The most common aetiologies were mesenteric ischaemia (n = 42, 45%) and adhesional/herniae-related strangulation (n = 41, 44%). In 50 patients a bowel resection was performed. Overall rates of anastomosis after resection, reoperation and 30-day mortality were 48% (n = 24/50, one leak), 12% and 18%, respectively. FA changed management in 27 (29%) patients. In four patients (4% overall), resection was avoided and in 21 (23%) extra bowel length was preserved (median 50 cm of bowel saved, IQR 28-98) although three patients developed further ischaemia. FA prompted extended resection (median of 20 cm, IQR 10-50 extra bowel) in six (6%) patients.Conclusion: Intraoperative use of FA impacts surgical decisions regarding bowel resection for intestinal ischaemia, potentially enabling bowel preservation in approximately one out of four patients. Prospective studies are needed to optimize the best use of this technology for this indication and to determine standards for the interpretation of FA images and the potential subsequent need for second-look surgeries. [ABSTRACT FROM AUTHOR]

Background: COVID-19 appears to be associated with a high risk of venous thromboembolism (VTE). We aimed to systematically review and meta-analyze the risk of clinically relevant VTE in patients hospitalized for COVID-19. Methods: This meta-analysis included original articles in English published from January 1st, 2020 to June 15th, 2020 in Pubmed/MEDLINE, Embase, Web of science, and Cochrane. Outcomes were major VTE, defined as any objectively diagnosed pulmonary embolism (PE) and/or proximal deep vein thrombosis (DVT). Primary analysis estimated the risk of VTE, stratified by acutely and critically ill inpatients. Secondary analyses explored the separate risk of proximal DVT and of PE; the risk of major VTE stratified by screening and by type of anticoagulation. Results: In 33 studies (n = 4009 inpatients) with heterogeneous thrombotic risk factors, VTE incidence was 9% (95%CI 5–13%, I2 = 92.5) overall, and 21% (95%CI 14–28%, I2 = 87.6%) for patients hospitalized in the ICU. Proximal lower limb DVT incidence was 3% (95%CI 1–5%, I2 = 87.0%) and 8% (95%CI 3–14%, I2 = 87.6%), respectively. PE incidence was 8% (95%CI 4–13%, I2 = 92.1%) and 17% (95%CI 11–25%, I2 = 89.3%), respectively. Screening and absence of anticoagulation were associated with a higher VTE incidence. When restricting to medically ill inpatients, the VTE incidence was 2% (95%CI 0–6%). Conclusions: The risk of major VTE among COVID-19 inpatients is high but varies greatly with severity of the disease. These findings reinforce the need for the use of thromboprophylaxis in all COVID-19 inpatients and for clinical trials testing different thromboprophylaxis regimens in subgroups of COVID-19 inpatients. Trial registration: The review protocol was registered in PROSPERO International Prospective Register of Systematic Reviews (CRD42020193369). [ABSTRACT FROM AUTHOR]

Purpose: The comparison between haemorrhoidal treatments is still unclear. Attempts have been made to adopt a unifying postoperative scoring system and thus ensure adequate comparison between clinical trials. We aimed to systematically review the available outcome scores of haemorrhoidal treatment. Methods: MEDLINE/Pubmed, Web of science, Embase and Cochrane were searched from database implementation until the December 6th 2019. All studies describing or referencing a score to assess haemorrhoidal disease treatment were included. Likert scale alone, incontinence score alone, general assessment of quality of life or scores developed for other proctologic disorders were excluded. The main outcome measures were validation of the scores and correlation of the score items to the core outcome set for haemorrhoidal disease developed by the European Society of Coloproctology. Results: From the 633 records initially screened, 22 studies were included: 8 original articles describing a scoring system and 14 referencing a previously described scoring system. Only 1 score was validated by an external prospective cohort. All the scores evaluated the symptoms of haemorrhoidal disease. No score integrated the disease recurrences or patient's satisfaction. Scores values tended to decrease postoperatively. Conclusions: The scores described by Gerjy et al. and by Shanmugan et al. are available questionnaires, which have been validated and used in various studies. These scores might help researchers for comparative studies between treatment modalities and optimize haemorrhoids treatment. [ABSTRACT FROM AUTHOR]

Background: Xenotransplantation has made tremendous progress over the last decade. Methods: We discuss kidney and heart xenotransplantation, which are nearing initial clinical trials. Results: Life sustaining genetically modified kidney xenografts can now last for approximately 500 days and orthotopic heart xenografts for 200 days in non‐human primates. Anti‐swine specific antibody screening, preemptive desensitization protocols, complement inhibition and targeted immunosuppression are currently being adapted to xenotransplantation with the hope to achieve better control of antibody‐mediated rejection (AMR) and improve xenograft longevity. These newest advances could probably facilitate future clinical trials, a significant step for the medical community, given that dialysis remains difficult for many patients and can have prohibitive costs. Performing a successful pig‐to‐human clinical kidney xenograft, that could last for more than a year after transplant, seems feasible but it still has significant potential hurdles to overcome. The risk/benefit balance is progressively reaching an acceptable equilibrium for future human recipients, e.g. those with a life expectancy inferior to two years. The ultimate question at this stage would be to determine if a "proof of concept" in humans is desirable, or whether further experimental/pre‐clinical advances are still needed to demonstrate longer xenograft survival in non‐human primates. Conclusion: In this review, we discuss the most recent advances in kidney and heart xenotransplantation, with a focus on the prevention and treatment of AMR and on the recipient's selection, two aspects that will likely be the major points of discussion in the first pig organ xenotransplantation clinical trials. [ABSTRACT FROM AUTHOR]

Numerous potential predictors of adverse outcomes have been reported but their performance and utilization in practice seem heterogenous. This study aimed to systematically review the literature on the role and value of predictors of complications after hepatectomy. A systematic review following the PRISMA guidelines was performed. Studies on liver transplant were excluded. Only studies assessing overall or major complications were included. A total of 10′965 abstracts were screened. After application of exclusion criteria, 72 articles including 68′480 patients were included. A total of 72 markers with 48 pre-, 9 intra- and 15 postoperative factors were identified as predictors of complications. Preoperative and intraoperative predictive markers retrieved several times with the highest odds ratios (OR) were ASA score (OR range: 1.3–7.5, significant in 8 studies) and intraoperative need for red blood cell transfusion (OR range: 1.2-17.1, significant in 24 studies), respectively. Numerous markers have been described to predict the complication risk after hepatectomy. Because of their intrinsic characteristics, most markers such as ASA score and need for red blood cell transfusion are of limited clinical interest. There is a clear need to identify new biomarkers and to develop scores that could easily be implemented in clinical practice. [ABSTRACT FROM AUTHOR]

Non-excisional laser therapies are emerging treatment for grades II and III hemorrhoidal disease (HD). However, so far, their efficiency is based on low-level evidence. Therefore, we aimed to systematically review the efficiency of non-excisional laser therapies for HD. MEDLINE/Pubmed, Web of science, Embase, and Cochrane were searched from database implementation until the April 17th, 2020. We included studies reporting at least one of surgical indicators of postoperative outcomes of laser therapies, encompassing laser hemorrhoidoplasty (LH) and hemorrhoidal laser procedure (HeLP). Fourteen studies describing LH and HeLP were included, representing 1570 patients. The main intraoperative complication was bleeding (0–1.9% of pooled patients for LH, 5.5–16.7% of pooled patients for HeLP). Postoperative complications occurred in up to 64% of patients after LH and 23.3% after HeLP. Resolution of symptoms ranged between 70 and 100% after LH and between 83.6 and 90% after HeLP. Moreover, four randomized controlled trials included in our review reported similar resolution after LH compared with hemorrhoidectomy or mucopexy and after HeLP compared with rubber band ligation. Recurrence rate was reported to range between 0 and 11.3% after LH and between 5 and 9.4% after HeLP. When compared with hemorrhoidectomy, LH showed conflicting results with one randomized controlled trial reporting similar recurrence rate, but another reporting decreased recurrences associated with hemorrhoidectomy. Laser therapies showed lower postoperative pain than hemorrhoidectomy or rubber band ligation. LH and HeLP are safe and effective techniques for the treatment of grades II and III HD. [ABSTRACT FROM AUTHOR]

Purpose: Fifteen percent of patients undergoing elective sigmoidectomy will present a diverticulitis recurrence, which is associated with significant costs and morbidity. We aimed to systematically review the risk factors associated with recurrence after elective sigmoidectomy. Methods: PubMed/MEDLINE, Embase, Cochrane, and Web of Science were searched for studies published until May 1, 2020. Original studies were included if (i) they included patients undergoing sigmoidectomy for diverticular disease, (ii) they reported postoperative recurrent diverticulitis, and (iii) they analyzed ≥ 1 variable associated with recurrence. The primary outcome was the risk factors for recurrence of diverticulitis after sigmoidectomy. Results: From the 1463 studies initially screened, six studies were included. From the 1062 patients included, 62 patients recurred (5.8%), and six variables were associated with recurrence. Two were preoperative: age (HR = 0.96, p = 0.02) and irritable bowel syndrome (33.3% with recurrence versus 12.1% without recurrence, p = 0.02). Two were operative factors: uncomplicated recurrent diverticulitis as indication for surgery (73.3% with recurrence versus 49.9% without recurrence, p = 0.049) and anastomotic level (colorectal: HR = 11.4, p = 0.02, or colosigmoid: OR = 4, p = 0.033). Two were postoperative variables: the absence of active diverticulitis on pathology (39.6% with recurrence versus 26.6% without recurrence) and persistence of postoperative pain (HR = 4.8, p < 0.01). Conclusion: Identification of preoperative variables that predict the occurrence of diverticulitis recurrence should help surgical decision-making for elective sigmoidectomy, while peri- and postoperative factors should be taken into account for optimal patient follow-up. [ABSTRACT FROM AUTHOR]

Purpose: Treatment of lateral lymph node metastasis in rectal cancer is still under debate. While these nodes are routinely resected by Japanese teams, neoadjuvant radiochemotherapy alone is performed in Western countries. We aimed to systematically report the current literature assessing the overall and disease-free survivals of patients with rectal cancer treated with total mesorectal resection (TME) with or without lateral lymph node dissection (LLND). Methods: MEDLINE/Pubmed, Embase, Cochrane, and Web of Science were searched from database implementation until 19 January 2019. Studies reporting overall survival or recurrence-free survival in patients with LLND for rectal cancer were included. We excluded studies including patients with recurrent rectal cancer, multivisceral resection, and/or without control group (patients with rectal surgery without LLND). Results: Eleven studies were included, accounting for a total of 4159 patients. Overall survival ranged between 55.6 and 92.6% for TME with LLND versus 49.2 and 90.2% for TME alone, with one study reporting statistically significant benefit of LLND. Recurrence-free survival ranged between 58.3 and 74.1% for TME with LLND versus 39.5 and 76.5% for TME alone. Two studies showed statistically significant differences between the two strategies, one randomized controlled trial showed improved recurrence-free survival in TME alone group (74.5% versus 74.1% with LLND at 5 years) and one observational retrospective study reported increased recurrence-free survival with more extensive resection (65.4% versus 39.5% without LLND, at 5 years). Conclusion: Benefits of LLND are not clear and further randomized controlled trials should be performed to determine which strategy would allow improving survival in rectal cancer patients. Trial registration: The study protocol was registered in PROSPERO prior to study screening (CRD42019123181) and published in September 2019. [ABSTRACT FROM AUTHOR]

Background: In high-risk patients with acute cholecystitis, antibiotics with or without percutaneous drainage of the gallbladder followed by delayed cholecystectomy (DC) can be performed. This study aimed to review our current management of elderly patients with acute cholecystitis treated with DC.Methods: All consecutive patients older than 70 with acute cholecystitis treated primarily with antibiotics with or without percutaneous drainage followed by DC between 2006 and 2015 were retrospectively reviewed.Results: Overall 105 elderly patients had acute cholecystitis with planned DC. Ninety-three patients had antibiotherapy alone at first. Twenty-eight patients needed percutaneous drainage either in intention to treat (n = 12) or due to failure of antibiotic treatment (n = 16). Nine (32%) versus 11 patients (12%) required an emergency cholecystectomy (EC) due to failure of percutaneous drainage or antibiotic treatment, respectively. Eighteen patients (64%) underwent DC after percutaneous drainage. Postoperative morbidity was 39% (7/18) after DC in the percutaneous drainage group, and 1 patient died. Compared to DC after antibiotherapy (n = 53), elderly patients who underwent DC after percutaneous drainage (n = 18) had longer median hospital stay (10 days versus 3 days, P = .001) and higher postoperative complications (7/18 versus 6/53, P = .015).Conclusion: In elderly patients with acute cholecystitis, DC can be a good alternative to EC. However, after percutaneous drainage DC is associated with high complication rate and long hospital stay. [ABSTRACT FROM AUTHOR]

The article discusses the destruction of the Hoopoe' habitats and the disappearance of its food following the massive use of phytosanitary products and a recent increase in the number of migrating sightings and the launch of a conservation project in 2007 in Switzerland.

The pedagogic activity, scientific work, recognitions and work carried out in the Internationalist Mission by the university graduate Vivian Benito Valenciano are exalted, who with 33 years of working experience constitutes a personality of obligatory consultation when it is sought to deepen in the history of the Nursing - Technology Faculty in Santiago de Cuba, of which she is founder. She was in the the institution since her technical studies, when it was Health Polytechnic, in which she assumed diverse responsibilities; at the moment she stays as a professor of the Medical Computer Science Department where she performes a meritorious work. [ABSTRACT FROM AUTHOR]

Dietary restriction (DR) is best known for extending lifespan in experimental model organisms, but also increases resistance to a variety of clinically relevant stressors, including those associated with surgery. Extended periods of DR, lasting months to years, are required for optimal longevity benefits in rodents, but short-term dietary preconditioning (less than 1 week) remarkably protects from acute injury. Here, we discuss recent advances in our understanding of the mechanistic basis of short-term DR and fasting in the context of surgical stress resistance, including upstream amino acid sensing by the GCN2 and mTORC1 pathways, and downstream effector mechanisms including increased insulin-dependent prosurvival signaling and elevated endogenous hydrogen sulfide production. We also review the current trend in preoperative nutrition away from preoperative fasting and towards carbohydrate loading. Finally, we discuss the rationale for the nonmutually exclusive use of brief DR or pharmacological DR mimetics to precondition against the stress and potential complications of surgery. [ABSTRACT FROM AUTHOR]

Imaging single proteins has been a long-standing ambition for advancing various fields in natural science, as for instance structural biology, biophysics, and molecular nanotechnology. In particular, revealing the distinct conformations of an individual protein is of utmost importance. Here, we show the imaging of individual proteins and protein complexes by low-energy electron holography. Samples of individual proteins and protein complexes on ultraclean freestanding graphene were prepared by soft-landing electrospray ion beam deposition, which allows chemical- and conformational-specific selection and gentle deposition. Low-energy electrons do not induce radiation damage, which enables acquiring subnanometer resolution images of individual proteins (cytochrome C and BSA) as well as of protein complexes (hemoglobin), which are not the result of an averaging process. [ABSTRACT FROM AUTHOR]

The adipose organ, which comprises brown, white and beige adipocytes, possesses remarkable plasticity in response to feeding and cold exposure. The development of beige adipocytes in white adipose tissue (WAT), a process called browning, represents a promising route to treat metabolic disorders. While surgical procedures constantly traumatize adipose tissue, its impact on adipocyte phenotype remains to be established. Herein, we studied the effect of trauma on adipocyte phenotype one day after sham, incision control, or surgical injury to the left inguinal adipose compartment. Caloric restriction was used to control for surgery-associated body temperature changes and weight loss. We characterized the trauma-induced cellular and molecular changes in subcutaneous, visceral, interscapular, and perivascular adipose tissue using histology, immunohistochemistry, gene expression, and flow cytometry analysis. After one day, surgical trauma stimulated adipose tissue browning at the site of injury and, importantly, in the contralateral inguinal depot. Browning was not present after incision only, and was largely independent of surgery-associated body temperature and weight loss. Adipose trauma rapidly recruited monocytes to the injured site and promoted alternatively activated macrophages. Conversely, PDGF receptor-positive beige progenitors were reduced. In this study, we identify adipose trauma as an unexpected driver of selected local and remote adipose tissue browning, holding important implications for the biologic response to surgical injury. [ABSTRACT FROM AUTHOR]

We have designed, fabricated and tested a micron-sized electron column with an overall length of about 700 microns comprising two electron lenses; a micro-lens with a minimal bore of 1 micron followed by a second lens with a bore of up to 50 microns in diameter to shape a coherent low-energy electron wave front. The design criteria follow the notion of scaling down source size, lens-dimensions and kinetic electron energy for minimizing spherical aberrations to ensure a parallel coherent electron wave front. All lens apertures have been milled employing a focused ion beam and could thus be precisely aligned within a tolerance of about 300 nm from the optical axis. Experimentally, the final column shapes a quasi-planar wave front with a minimal full divergence angle of 4 mrad and electron energies as low as 100 eV. [ABSTRACT FROM AUTHOR]

The addition of selenate or selenite to common fertilizers for crop production could be an effective way of producing selenium-rich food and feed. However, this would be feasible only if the increase in plant selenium (Se) content did not negatively influence the uptake of other essential elements. We therefore need to understand the interactions between Se and other major and trace elements during uptake by the plant. This study aimed to evaluate the influence of inorganic forms of Se on the accumulation of selected macronutrients (Ca and Mg) and micronutrients (Fe, Zn, Mn and Cu). Those essential elements are involved in the oxidative balance of cells. Zea mays seedlings were grown hydroponically in growth chambers in nutrient solutions to which we added 10, 50 or 1000 μg.L −1 of selenate and/or selenite. Cation accumulation was significantly affected by the addition of 50 μg.L −1 or 1000 μg.L −1 Se, but not by the presence of 10 μg.L −1 of Se in the nutrient solution. The highest concentration (1000 μg.L −1 ) of Se in the nutrient solution affected the accumulation of essential cations in Zea mays : selenate tended to increase the accumulation of Mg, Zn and Mn, whereas a selenate/selenite mixture tended to decrease the accumulation of Ca, Mg, Zn and Mn. Only Fe accumulation was unaffected by Se whatever its form or concentration. Selenium may also affect the distribution of cations on Zea mays . For example, levels of Mg and Zn translocation to the shoots were lower in the presence of selenite. [ABSTRACT FROM AUTHOR]

The current state of the art in structural biology is led by NMR, X-ray crystallography and TEM investigations. These powerful tools however all rely on averaging over a large ensemble of molecules. Here, we present an alternative concept aiming at structural analysis at the single molecule level. We show that by combining electron holography and coherent diffraction imaging estimations concerning the phase of the scattered wave become needless as the phase information is extracted from the data directly and unambiguously. Performed with low-energy electrons the resolution of this lens-less microscope is just limited by the De Broglie wavelength of the electron wave and the numerical aperture, given by detector geometry. In imaging freestanding graphene, a resolution of 2 Å has been achieved revealing the 660.000 unit cells of the graphene sheet from a single data set. Once applied to individual biomolecules the method shall ultimately allow for non-destructive imaging and imports the potential to distinguish between different conformations of proteins with atomic resolution. [ABSTRACT FROM AUTHOR]

Modern structural biology relies on Nuclear Magnetic Resonance (NMR), X-ray crystallography, and cryo-electron microscopy for gaining information on biomolecules at nanometer, sub-nanometer, or atomic resolution. All these methods, however, require averaging over a vast ensemble of entities, and hence knowledge on the conformational landscape of an individual particle is lost. Unfortunately, there are now strong indications that even X-ray free electron lasers will not be able to image individual molecules but will require nanocrystal samples. Here, we show that non-destructive structural biology of single particles has now become possible by means of low-energy electron holography. As an example, individual tobacco mosaic virions deposited on ultraclean freestanding graphene are imaged at 1 nm resolution revealing structural details arising from the helical arrangement of the outer protein shell of the virus. Since low-energy electron holography is a lens-less technique and since electrons with a deBroglie wavelength of approximately 1 Å do not impose radiation damage to biomolecules, the method has the potential for Angstrom resolution imaging of single biomolecules. [ABSTRACT FROM AUTHOR]

Venous bypass grafts often fail following arterial implantation due to excessive smooth muscle cells (VSMC) proliferation and consequent intimal hyperplasia (IH). Intercellular communication mediated by Connexins (Cx) regulates differentiation, growth and proliferation in various cell types. Microarray analysis of vein grafts in a model of bilateral rabbit jugular vein graft revealed Cx43 as an early upregulated gene. Additional experiments conducted using an ex-vivo human saphenous veins perfusion system (EVPS) confirmed that Cx43 was rapidly increased in human veins subjected ex-vivo to arterial hemodynamics. Cx43 knock-down by RNA interference, or adenoviral-mediated overexpression, respectively inhibited or stimulated the proliferation of primary human VSMC in vitro. Furthermore, Cx blockade with carbenoxolone or the specific Cx43 inhibitory peptide 43gap26 prevented the burst in myointimal proliferation and IH formation in human saphenous veins. Our data demonstrated that Cx43 controls proliferation and the formation of IH after arterial engraftment. [ABSTRACT FROM AUTHOR]

Quantification of selenium bioavailability from foods is a key challenge following the discovery of the antioxidant role of this micronutrient in human health. This study presents the uptake, accumulation and rate of metabolization in mature Zea mays plants grown in hydroponic solution supplemented with selenate or selenite. Selenium content was lower in plants supplemented with selenate and accumulated mainly in the leaves compared with selenite-treated plants where the selenium was retained in the roots. Selenite-treated grains accumulated more selenium. Selenate was metabolized less than selenite in whole plants, but in grains selenium was present exclusively as organic selenium compounds. For humans, the bioavailability of organic selenium was evaluated at 90% compared with only 50% for inorganic forms. Our results show that the potential for selenium bioavailability is increased with selenite treatment. [ABSTRACT FROM AUTHOR]

The pedagogical activity, scientific performance and work as leader of the Licentiate Ursula López Fondén, who at her 42 years of work constitutes a personality of compulsory advice when it is intended to deepen in the history of the Health Technology Faculty from Santiago de Cuba, are highlighted. She worked in the institution from its beginnings, when it was a Health Polytechnic, in which she had diverse responsibilities, such as subdirector, head and dean; up to 2005, when this institution became the Health Technology Faculty, where she is linked to teaching as a consulting teacher. [ABSTRACT FROM AUTHOR]

Low-energy electrons (30-250 eV) have been successfully employed for imaging individual biomolecules. The most simple and elegant design of a low-energy electron microscope for imaging biomolecules is a lensless setup that operates in the holographic mode. In this work we address the problem associated with the reconstruction from the recorded holograms. We discuss the twin image problem intrinsic to inline holography and the problem of the so-called biprism-like effect specific to low-energy electrons. We demonstrate how the presence of the biprism-like effect can be efficiently identified and circumvented. The presented sideband filtering reconstruction method eliminates the twin image and allows for reconstruction despite the biprism-like effect, which we demonstrate on both, simulated and experimental examples. [ABSTRACT FROM AUTHOR]

An ideal support for an electron microscopy should be as thin as possible and be able to interact as little as possible with the primary electrons. Since graphene is atomically thin and made up of carbon atoms arranged in a honeycomb lattice, the potential to use graphene as a substrate in electron microscopy is enormous. Until now graphene has hardly ever been used for this purpose because the cleanliness of freestanding graphene before or after deposition of the objects of interest was insufficient. We demonstrate here by means of low-energy electron holographic imaging that freestanding graphene prepared with a platinum-metal catalysis method remains ultraclean even after re-exposure to ambient conditions and deposition of gold nanorods from the liquid phase. In the holographic reconstruction of gold particles the organic shell surrounding the objects is apparent while it is not detectable in SEM images of the very same sample, demonstrating the tremendous potential of low-energy electron holography for imaging of graphene-supported single biomolecules. [ABSTRACT FROM AUTHOR]

Abstract: The saphenous vein is the conduit of choice in bypass graft procedures. Haemodynamic factors play a major role in the development of intimal hyperplasia (IH), and subsequent bypass failure. To evaluate the potential protective effect of external reinforcement on such a failure, we developed an ex vivo model for the perfusion of segments of human saphenous veins under arterial shear stress. In veins submitted to pulsatile high pressure (mean pressure at 100 mmHg) for 3 or 7 days, the use of an external macroporous polyester mesh 1) prevented the dilatation of the vessel, 2) decreased the development of IH, 3) reduced the apoptosis of smooth muscle cells, and the subsequent fibrosis of the media layer, 4) prevented the remodelling of extracellular matrix through the up-regulation of matrix metalloproteinases (MMP-2, MMP-9) and plasminogen activator type I. The data show that, in an experimental ex vivo setting, an external scaffold decreases IH and maintains the integrity of veins exposed to arterial pressure, via increase in shear stress and decrease wall tension, that likely contribute to trigger selective molecular and cellular changes. [Copyright &y& Elsevier]

We have imaged a freestanding graphene sheet of 210 nm in diameter with 2 Å resolution by combining coherent diffraction and holography with low-energy electrons. The entire sheet is reconstructed from a single diffraction pattern displaying the arrangement of 660.000 individual graphene unit cells at once. Given the fact that electrons with kinetic energies of the order of 100 eV do not damage biological molecules, it will now be a matter of developing methods for depositing individual proteins onto such graphene sheets. [ABSTRACT FROM AUTHOR]

Background and aims: Selenium is an essential micro-nutrient for animals, humans and microorganisms; it mainly enters food chains through plants. This study proposes to explore effect of inorganic Se forms on its uptake and accumulation in Zea mays. Methods: Zea mays was grown in a controlled-atmosphere chamber for 2 weeks in a hydroponic solution of low-concentration selenium (10 μg/L (i.e.0.12 μM) or 50 μg/L (i.e. 0.63 μM) of Se). For each concentration, four treatments were defined: control (without selenium), selenite alone, selenate alone and selenite and selenate mixed. Results: At low concentrations, selenium did not affect the biomass production of Zea mays. However, for both concentrations, Se accumulation following a selenite-only treatment was always higher than with selenate-only. Moreover, in the selenate-only treatment, Se mainly accumulated in shoots whereas in the selenite-only treatment, Se was stocked more in the roots. Interactions between selenate and selenite were observed only at the higher concentration (0.63 μM of selenium in the nutrient solution). Conclusions: Se form and concentration in the nutrient solution strongly influenced the absorption, allocation and metabolism of Se in Zea mays. Selenate seems to inhibit selenite absorption by the roots. [ABSTRACT FROM AUTHOR]

We investigated the utility of free-standing graphene as a transparent sample carrier for imaging nanometer-sized objects by means of low-energy electron holography. The sample preparation for obtaining contamination-free graphene as well as the experimental setup and findings are discussed. For incoming electrons with 66 eV kinetic energy, graphene exhibits 27% opacity per layer. Hence, electron holograms of nanometer-sized objects adsorbed on free-standing graphene can be recorded and numerically reconstructed to reveal the object's shapes and distribution. Furthermore, a Moiré effect has been observed with free-standing graphene multi-layers. [ABSTRACT FROM AUTHOR]

Explosive eruptions associated with tephra deposits that are only exposed in proximal areas are difficult to characterize. In fact, the determination of physical parameters such as column height, mass eruption rate, erupted volume, and eruption duration is mainly based on empirical models and is therefore very sensitive to the quality of the field data collected. We have applied and compared different modeling approaches for the characterization of the two main tephra deposits, the Lower Pumice (LP) and Upper Pumice (UP) of Nisyros volcano, Greece, which are exposed only within 5 km of the probable vent. Isopach and isopleth maps were compiled for two possible vent locations (on the north and on the south rim of the caldera), and different models were applied to calculate the column height, the erupted volume, and the mass eruption rate. We found a column height of about 15 km above sea level and a mass eruption rate of about 2 × 10 kg/s for both eruptions regardless of the vent location considered. In contrast, the associated wind velocity for both UP and LP varied between 0 and 20 m/s for the north and south vent, respectively. The derived erupted volume for the south vent (considered as the best vent location) ranges between 2 and 27 × 10 m for the LP and between 1 and 5 × 10 m for the UP based on the application of four different methods (integration of exponential fit based on one isopach line, integration of exponential and power-law fit based on two isopach lines, and an inversion technique combined with an advection-diffusion model). The eruption that produced the UP could be classified as subplinian. Discrepancies associated with different vent locations are smaller than the discrepancies associated with the use of different models for the determination of erupted mass, plume height, and mass eruption rate. Proximal outcrops are predominantly coarse grained with ≥90 wt% of the clasts ranging between −6ϕ and 0ϕ. The associated total grainsize distribution is considered to result from a combination of turbulent fallout from both the plume margins and the umbrella region, and as a result, it is fines-depleted. Given that primary deposit thickness observed on Nisyros for both LP and UP is between 1 and 8 m, if an event of similar scale were to happen again, it would have a significant impact on the entire island with major damage to infrastructure, agriculture, and tourism. Neighboring islands and the continent could also be significantly affected. [ABSTRACT FROM AUTHOR]

Abstract: Intrinsic spherical aberrations of electron lenses have been the major resolution limiting factor in electron microscopes for several decades. While effective correctors have recently been implemented, an alternative to correct these aberrations is to circumvent them by scaling down lens dimensions by several orders of magnitude. We have fabricated electrostatic lenses exhibiting one micrometer diameter apertures and evaluated their beam forming properties against predictions from numerical ray tracing simulations. It turns out that it is routinely possible to shape a paraxial low-energy electron beam by such micron-sized lenses. Beam profiles have been measured both at a distant detector as well as in a plane close to the lens. It is shown that the lens can form a parallel beam extending no more than 800nm from the optical axes at a distance of beyond the lens exit. We believe that these findings constitute a prerequisite to derive novel tools for high resolution microscopy using low-energy electrons. [ABSTRACT FROM AUTHOR]

Abstract: By means of congruent evaporation, we have deposited CdTe and PbTe onto the oxidized fivefold-symmetry surface of an icosahedral AlPdMn quasicrystal. This procedure results in the formation of nanocrystals in both cases. While the azimuthal orientations of the crystallites are random, the polar orientations are well defined. The crystalline CdTe and PbTe domains expose their (111) and (001) faces, respectively, which are aligned parallel to the pentagonal surface of the quasicrystal. The nanometric size of the domains is not a result of the lattice mismatch between the growing film and the substrate as usually observed in molecular-beam epitaxy, but of the limited size of the oxide domains of the substrate surface. [Copyright &y& Elsevier]

Abstract: The Debye-temperature of the pentagonal surface of the icosahedral AlPdMn quasicrystal (QC) is measured by means of low-energy electron diffraction after the absorption of different amounts of Si. We observe an increase of the surface Debye-temperature from  K for the freshly prepared surface to  K after the absorption of 60-Å Si. Because the quasicrystalline order persists at the surface in spite of the diffusion of Si into the substrate, we suggest that the diffusion is dominated by a vacancy-mediated process. [Copyright &y& Elsevier]

A quasicrystal is a solid with an aperiodic atomic distribution, but displaying discrete diffraction pattern. At an interface where an ordinary crystal and a quasicrystal intersect, the lack of commensurability between the structures leads to misfits on atomic scale resulting in a wealth of novelties. Here, we present experimental observations on three essentially different cases: Al, Fe, and Si ultra-thin layers grown in vacuum on the pentagonal surface of an icosahedral Al-Pd-Mn quasicrystal. In all three cases, the growing layer decays into nm-size islands. Al is the major alloy component of the substrate material and provides a natural tool to investigate the surface structure. Fe offers an insight into nano-scale magnetism. Si is a classical candidate to explore quantum-confinement effects. [ABSTRACT FROM AUTHOR]

We have generated cubic Al alloys as commensurate single crystals on the tenfold-symmetry surface of the quasicrystalline Al-Ni-Co alloy by ion bombarding its surface. We find that the crystal-quasicrystal interface contains several alignments of mutual high-symmetry directions and planes. In order to explore the structural matching conditions at the crystal-quasicrystal interface, we have grown Al films on the decagonal surface of Al-Ni-Co by vapor deposition. The initial growth mode of Al is commensurate. As the coverage is increased, Al starts to grow in cubic textures breaking into multi-twinned, few-nanometer- large domains. The symmetry of the substrate determines thereby the orientation of the domains, while the degree of structural mismatch between the crystal and the quasicrystal limits the domain size. [ABSTRACT FROM AUTHOR]

Abstract: With the aim to improve the fibrinolytic properties of carbons by different biological and electrochemical treatments, we modified graphite surfaces by fibrinogen adsorption and subsequent application of various constant potentials before submitting them to plasminogen adsorption. First, we verified that plasminogen (purified or present in human plasma) could adsorb onto these modified surfaces and that adsorbed plasminogen could be converted by t-PA (the principal physiological activator of plasminogen) to adsorbed plasmin. The catalytic properties of the generated enzyme were characterized in assay solutions containing t-PA, fibrinogen and the chromogenic substrate S-2403 (pyroGlu-Phe-Lys-p-nitroaniline, HCl). Experiments showed that the application of electrical potentials to the fibrinogen coating could indirectly affect the properties of the material. In the case of anodic potentials, the amidolytic activity of the generated plasmin was significantly enhanced. Especially, this activity was 10 times higher at a particular potential value. [Copyright &y& Elsevier]

The formation of stable films of nickel hexacyanoferrate (NiHCF) onto electrodes containing MmNi3.55Al0.3Mn0.4Co0.75 (Mm=Misch metal) as model material for AB5-type alloys is reported. By comparison with the behavior of NiHCF prepared by chemical synthesis, NiHCF films developed onto carbon paste electrodes containing AB5 powder exhibit the same stability, cation exchange and electrocatalytic properties. Then, the intermetallic AB5 compound appears to be a suitable starting material to prepare NiHCF surfaces. [Copyright &y& Elsevier]

A simple SISO two-degree-of-freedom pole-placement design method is presented that provides ℓ2-optimal tracking of a given reference signal. The closed-loop pole locations are first chosen by the system designer. The closed-loop zeros are then placed in an optimal fashion by a computationally inexpensive algorithm to achieve asymptotic tracking with an optimal transient response. The preview approach, which has become a common method for dealing with systems which have non-minimum phase behavior, can then optionally be used to further improve the transient behavior for both minimum phase and non-minimum phase systems. Unlike previous results based on the preview approach, the solution presented here takes into consideration the closed-loop pole dynamics, and is ℓ2 optimal with respect to all other two-degree-of-freedom preview controllers with the same closed-loop poles. A simple solution to the H2 model matching problem, where the design parameter Q is not rational, but polynomial, is the heart of the solution method. [Copyright &y& Elsevier]

The amidolytic activity of plasmin (Pln) that spontaneously adsorbs from solutions to modified-graphite (GR) and glassy carbon (GL) surfaces was studied in the 10–45 °C temperature range in the presence of a chromogenic substrate. Surfaces were modified with a coating of fibrinogen, either electrochemically oxidized or not. The effect of an additional modification via deposition of Langmuir–Blodgett films of behenic acid (BA-LB) onto the former surfaces, thus leading to either hydrophobic or hydrophilic surfaces according to the number of deposed layers, was examined. In all cases results showed the occurrence of a first order transition which strongly and transiently increases the surface activity of Pln. At BA-LB surfaces, the most prominent change compared with other coatings was a significant enhancement of the critical temperature Tc that characterizes the beginning of the transition. When fibrinogen was present in the solution, the transition was no longer observable up to 37 °C as shown by the linear kinetics exhibited by surfaces bearing oxidized fibrinogen. [Copyright &y& Elsevier]

The characterization of seismic hazard of province and Santiago de Cuba city in terms of intensity, acceleration, velocity and displacement is presented. Seismic hazard's parameters are show in maps using recurrence periods for each value of these ones and in probabilistic form for different times of useful life and probability of occurrence for a grid of 1 km² in Santiago de Cuba basin, including different hazard's levels. All the seismic hazard's parameters were prepared like a Digital Data Base for their implementation in GIS with the aim to prevention and seismological disaster management, which are important for planning, projection and design of development of these territories. Actually these parameters are the basis for city and land planning, also for others projects in this territory. In this way these ones are taking as a reference element in the preparedness plan by the Civil Defense in case of large earthquakes. [ABSTRACT FROM AUTHOR]

The professional qualities and the unconditional support to the Cuban revolution of Félix Fernando Leyva Urquiza, a doctor from Cienfuegos, are exalted. He had an active participation in the insurrectional fights and later on he stands out as specialist in radiology. When moving to Santiago de Cuba he began his educational work, where he puts his knowledge at the service of the preparation and training of the imagenology technicians in Santiago. [ABSTRACT FROM AUTHOR]

The sensitivity and specificity of polyclonal and monoclonal antibodies raised against anthrax spore preparations has been assessed by Western blotting. None of the antibodies studied were completely specific in recognizing the anthrax spore surface. A polyclonal serum recognized a wide range of spore surface epitopes and demonstrated limited cross-reaction with the near-neighbour species Bacillus cereus spore surface. Two monoclonal antibodies studied demonstrated more extensive cross-reaction with distant-neighbour species B. globigii and B. subtilis. These monoclonal antibodies did not react with spore surface epitopes but did bind strongly to vegetative cell epitopes in all four Bacillus species studied. [ABSTRACT FROM AUTHOR]

Focuses on the identification of PBSX-associated endolysins associated with defective prophages of Bacillus subtilis. Sequencing and characterization of the region comprising the N-acetylmuramoyl-L-analine amidase gene of prophage PBSX; Bacterial strains and plasmids; Nucleotide sequence of the PBSX genome region comprising xlyA, the gene encoding PX32.

Abstract: Today''s structural biology techniques require averaging over millions of molecules to obtain detailed structural information. Derivation of the molecular structure from a scattering experiment with just one single 3D-molecule imposes major challenges. Coherent and damage-free radiation is needed to ensure sufficient elastic scattering events before destroying the molecule and a means to solve the phase problem is wanted. We have devised such a scheme using coherent low-energy electrons shaped into a collimated beam by an electrostatic microlens. Initial experiments using a carbon nanotube sample demonstrate the feasibility of coherent low-energy electron diffraction on an individual nanometer-sized object. [Copyright &y& Elsevier]

Transplantation remains the preferred treatment for end‐stage kidney disease but is critically limited by the number of available organs. Xenografts from genetically modified pigs have become a promising solution to the loss of life while waiting for transplantation. However, the current clinical model for xenotransplantation will require off‐site procurement, leading to a period of ischemia during transportation. As of today, there is limited understanding regarding the preservation of these organs, including the duration of viability, and the associated molecular changes. Thus, our aim was to evaluate the effects of static cold storage (SCS) on α1,3‐galactosyltransferase knockout (GGTA1 KO) kidney. After SCS, viability was further assessed using acellular sub‐normothermic ex vivo perfusion and simulated transplantation with human blood. Compared to baseline, tubular and glomerular interstitium was preserved after 2 days of SCS in both WT and GGTA1 KO kidneys. Bulk RNA‐sequencing demonstrated that only eight genes were differentially expressed after SCS in GGTA1 KO kidneys. During sub‐normothermic perfusion, kidney function, reflected by oxygen consumption, urine output, and lactate production was adequate in GGTA1 KO grafts. During a simulated transplant with human blood, macroscopic and histological assessment revealed minimal kidney injury. However, GGTA1 KO kidneys exhibited higher arterial resistance, increased lactate production, and reduced oxygen consumption during the simulated transplant. In summary, our study suggests that SCS is feasible for the preservation of porcine GGTA1 KO kidneys. However, alternative preservation methods should be evaluated for extended preservation of porcine grafts. [ABSTRACT FROM AUTHOR]

We report angle-resolved electron transmission measurements through freestanding graphene sheets in the energy range of 18 to 30 eV above the Fermi level. The measurements are carried out in a low-energy electron point source microscope, which allows simultaneously probing the transmission for a large angular range. The characteristics of low-energy electron transmission through graphene depend on its electronic structure above the vacuum level. The experimental technique described here allows mapping of the unoccupied band structure of freestanding two-dimensional materials as a function of the energy and probing angle, respectively, in-plane momentum. Our experimental findings are consistent with theoretical predictions of a resonance in the band structure of graphene above the vacuum level [V. U. Nazarov, E. E. Krasovskii, and V. M. Silkin, Phys. Rev. B 87, 041405 (2013)]. [ABSTRACT FROM AUTHOR]

Low cardiac output is one of the most common complications after cardiac surgery. Levosimendan, a new inotrope agent, has been demonstrated in adult patient to be an effective treatment for this purpose when classical therapy is not effective. The aim of this study was to evaluate the effect of Levosimendan on cardiac output parameters in cardiac children with low cardiac output syndrome (LCOS.). We carried out a retrospective analysis on 62 children hospitalized in our pediatric intensive care unit (PICU) after cardiac surgery, which demonstrated LCOS not responding to classical catecholamine therapy and who received levosimendan as rescue therapy. LCOS parameters like diuresis, central venous oxygen saturation (SvO), venous-to-arterial CO difference (∆avCO), and plasmatic lactate were compared before therapy and at 3, 6, 12, and 24 h after the beginning of the levosimendan infusion. We also analyzed the effect on the Vasoactive-inotropic score (VIS), adverse events, and mortality. After the beginning of levosimendan infusion, diuresis (1.1 vs. 3.5 ml/kg/h, p = 0.001) and SvO (59.5 vs. 63.3%, p = 0.026) increased significantly during the 24 h of infusion, and at the same time, plasmatic lactate (2.3 vs. 1.3 mmol/l, p < 0.001) decreased. ∆avCO (10.8 vs. 9.4 mmHg, p = 0.21) and the VIS (44.5 vs. 22.5, p = 0.143) also decreased, but not significantly. No side effects were noted. The mortality in this patient group was 16%. Levosimendan is an effective treatment in children presenting LCOS after congenital heart surgery. Our study confirms the improvement of cardiac output already shown in other pediatric studies, with no undesirable side effects. [ABSTRACT FROM AUTHOR]