Search

Introduction There are many studies that analyse preoperative factors with a poor prognosis in patients undergoing surgery for colorectal carcinoma liver metastases, in order to avoid unnecessary surgery. However, there are few studies that evaluate the intra-and postoperative prognostic factors. The aim of this study is to analyse pre-, intra-, and postoperative prognostic factors in a series of 210 patients undergoing surgery for colorectal carcinoma liver metastases, with special emphasis on the postoperative factors that can give us information on the aggressiveness of the tumour and the curative effectiveness of the surgery. Patients and method Between September 1996 and December 2006, 210 patients undergoing surgery for colorectal carcinoma liver metastases in whom we analysed pre-, intra-, and postoperative factors of survival. Mean follow-up was 55 (3) months (range, 12–124 months). Results The postoperative mortality rate was 1.4% and the morbidity rate was 22%. Actuarial and disease-free survival at 1-, 3-, and 5-years was 89.9% versus 63%, 66.9% versus 32%, and 53.8% vs 23%, respectively. Among the preoperative factors analysed, the age >65 years and LM size >5 cm were independent predictors of poor overall survival, whereas the other 2 significant factors were obtained from those analysed postoperatively: presence of microsatellitosis and postoperative CEA levels (at 1 and 3 months). Conclusions In patients with colorectal carcinoma liver metastases we must take into account certain postoperative factors that can give us information on the aggressiveness of the tumour and the effectiveness of the surgery.

Introduction The resection of tumours of the anatomical left lobe is normally straightforward using either left lateral sectionectomy (LLSEC) or segmentectomy II or III. Our objective is to present the results of the laparoscopic approach and to consider whether this could be the “ideal technique” in liver surgery units where the surgeons have experience of laparoscopic liver surgery (LLSURG). Patients and methods We have studied patients with resected solid tumours of the anatomical left lobe using LLSURG (n = 18): ten cases with LLSEC and 8 cases with segmentectomy II or III. We carried out a comparative study with a control group of 18 patients operated on using the same surgical technique using open surgery (OS). Results There were no cases of mortality in either of the 2 groups (n = 36). Morbidity was similar (5.5% per group). For LLSEC, the LLSURG group (n = 10) had a shorter hospital stay (P = .005) and less surgical time (141 vs 159 min) (differences not significant), than the OS group. For segmentary resections II or III, in the LLSURG group (n = 8) there was greater use of the Pringle manoeuvre (P = .05), greater surgical time (P = .05) and a shorter hospital stay (4.8 vs 5.6 days) (differences not significant), than in the OS group. Conclusions LLSEC should be carried out by laparoscopy in centres where they have considerable experience. The patients may have a shorter hospital stay and spend less time in surgery than when OS is performed, with the same morbidity and mortality rates. Segmentectomy resections II or III carried out by laparoscopy involve a shorter hospital stay but longer surgery time and therefore the advantages are not as evident as they are for LLSEC.

Electron energy-loss spectroscopy - spectrum image (EELS-SI) tomography is a powerful tool to investigate the three dimensional chemical configuration in nanostructures. Here, we demonstrate, for the first time, the possibility to characterize the spatial distribution of Fe and Co cations in a complex FFeₓCo(₃₋ₓ)O₄/Co₃O₄ ordered mesoporous system. This hybrid material is relevant because of the ferrimagnetic/antiferromagnetic coupling and high surface area. We unambiguously prove that the EELS-SI tomography shows a sufficiently high resolution to simultaneously unravel the pore structure and the chemical signal.

Electron energy-loss spectroscopy-spectrum image (EELS-SI) tomography is a powerful tool to investigate the three dimensional chemical configuration in nanostructures. Here, we demonstrate, for the first time, the possibility to characterize the spatial distribution of Fe and Co cations in a complex FexCo(3-x)O4/Co3O4 ordered mesoporous system. This hybrid material is relevant because of the ferrimagnetic/antiferromagnetic coupling and high surface area. We unambiguously prove that the EELS-SI tomography shows a sufficiently high resolution to simultaneously unravel the pore structure and the chemical signal.

Weber, M.C. et al., Strain effects on epitaxial thin films of LaNiO3 grown on different single crystalline substrates are studied by Raman scattering and first-principles simulation. New Raman modes, not present in bulk or fully-relaxed films, appear under both compressive and tensile strains, indicating symmetry reductions. Interestingly, the Raman spectra and the underlying crystal symmetry for tensile and compressively strained films are different. Extensive mapping of LaNiO3 phase stability is addressed by simulations, showing that a variety of crystalline phases are indeed stabilized under strain which may impact the electronic orbital hierarchy. The calculated Raman frequencies reproduce the principal features of the experimental spectra, supporting the validity of the multiple strain-driven structural transitions predicted by the simulations., J.K., M.W., M.G., and J.I. acknowledge support from the National Research Fund, Luxembourg through a Pearl grant (Grant No. FNR/P12/4853155). ICMAB-CSIC authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015- 0496) and the MAT2014-56063-C2-1-R and MAT2013- 40581-P projects, and from Generalitat de Catalunya (2014 SGR 734). UB authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, project MAT2013-41506-P and from Generalitat de Catalunya (2014 SGR 672).

9 págs.; 6 figs., © 2015 American Chemical Society.We fabricate an Er3+/nano-Si ultrathin (≈ 4 nm) layer and explore its optical response from the near-UV to the near-IR, in the linear and nonlinear regimes. This nanohybrid layer combines the tunable broad-band light harvesting properties of nano-Si with the robust and sharp Er3+ light emission. Its unique nanostructure enables efficient nanometer-range transfer of the harvested energy to the Er3+ ions. Therefore, clear 1.54 μm Er3+ photoluminescence (PL) is observed under excitation at any photon energy (Eexc) from the visible to the near-UV, despite the small amount of Er3+ ions in the layer (, This work has been partly funded by the Spanish Ministry of Economy and Competitiveness, in the framework of the AMALIE TEC2012-38901-C02-01 and MAT2010-16407 research projects of the national R&D plan. J.T. acknowledges funding from the former Spanish Ministry for Research, Development and Innovation (Juan de la Cierva Fellowship JCI-2009-05098). J.M.R. thanks the CSIC for a JAE predoc grant.

Objective:There is currently no conclusive scientific evidence available regarding the role of the 18F-FDG PET/CT for detecting pulmonary metastases from colorectal cancer (PMCRC) in patients operated on for colorectal liver metastases (CRLM). In the follow up of patients who underwent surgery for CRLM, we compare CT-scan and 18F-FDG PET/CT in patients with PMCRC.Methods:We designed the study prospectively performing an 18F-FDG PET/CT on all patients operated on for CRLM where the CT-scan detected PMCRC during the follow up. We included patients who were operated on for PMCRC because the histological findings were taken as a control rather than biopsies.Results:Of the 101 pulmonary nodules removed from 57 patients, the CT-scan identified a greater number (89 nodules) than the 18F-FDG PET/CT (75 nodules) (p < 0.001). Sensitivity was greater with the CT-scan (90 vs 76%, respectively) with a lower specificity (50 vs 75%, respectively) than with the 18F-FDG PET/CT. There were no differences between positive-p...

In this work, we present characterization methods for the analysis of nanometer-sized devices, based on silicon and III-V nitride semiconductor materials. These methods are devised in order to take advantage of the aberration corrected scanning transmission electron microscope, equipped with a monochromator. This set-up ensures the necessary high spatial and energy resolution for the characterization of the smallest structures. As with these experiments, we aim to obtain chemical and structural information, we use electron energy loss spectroscopy (EELS). The low-loss region of EELS is exploited, which features fundamental electronic properties of semiconductor materials and facilitates a high data throughput. We show how the detailed analysis of these spectra, using theoretical models and computational tools, can enhance the analytical power of EELS. In this sense, initially, results from the model-based fit of the plasmon peak are presented. Moreover, the application of multivariate analysis algorithms to low-loss EELS is explored. Finally, some physical limitations of the technique, such as spatial delocalization, are mentioned.

Charge transport in nanocrystalline SiC with and without embedded Si nanocrystals (Si NCs) prepared by annealing of $a\ensuremath{-}\mathrm{S}{\mathrm{i}}_{1\ensuremath{-}x}{\mathrm{C}}_{x}:\mathrm{H}$ precursors is studied using temperature-dependent current-voltage measurements supported by electron spin resonance and mass spectrometry data. Transport is Ohmic in all films at all temperatures and the temperature dependence of conductivity shows that the materials behave as disordered semiconductors, exhibiting extended-state transport at high temperature and variable-range hopping transport at low temperature. Grain-boundary-, surface-, and interface-dominated transport is systematically ruled out. Films are $n$ type, and films with Si NCs exhibit up to ${10}^{3}$ times higher conductivity (up to $0.1\phantom{\rule{0.16em}{0ex}}\mathrm{S}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$) after exposure to a hydrogen plasma which passivates dangling bonds, particularly on Si NCs. A forming gas anneal does not have such an effect, indicating that atomic rather than molecular hydrogen is required. The conductivity of SiC films without Si NCs is largely unchanged by passivation and the Fermi level is not raised nearly as closely to the conduction band. This is attributed to a type I band offset between Si NCs and SiC that leads to extended-state conduction in films with Si NCs taking place in a Si network. This is confirmed by the dependence of the extended-state mobility on the volume fraction of excess Si. Variable-range hopping is relatively insensitive to the presence of excess Si and is hence considered to take place via shallow defect states throughout the volume of the films. The high conductivities are found to be a consequence of background doping by oxygen and nitrogen.

GaInP is a material commonly employed for the top subcells of different multijunction solar cells architectures. In this study, the performance of GaInP top cells has been improved by increasing the energy band gap with the use of Sb as a surfactant during the MOVPE growth of the structures. The optimization of the appropriate Sb molar flow was done by Reflectance Anisotropy Spectroscopy. Different characterization techniques have been employed to assess the effect of Sb on the morphology, microstructure and optoelectronic properties of the resulting GaInP grown with different Sb/P ratios. Finally, the performance of several GaInP subcells with different order parameters has been assessed.

Being able to directly relate the final properties with the intimate structure provides a unique insight into the functionality of materials and devices, especially when compared to the necessarily statistical nature of the information that can be retrieved by macroscopic measurements. In particular, the scale reduction associated with the Nanoscience and Nanotechnology revolution demands characterization tools capable of reaching an unprecedented resolution, in a wide range of fields, not only for standard quality control, but in order to understand the properties of matter at the nanoscale. Going from bigger to smaller devices, but also from elemental building blocks (even atoms) to bigger assemblies, basic properties and device functionalities meet. With its ability to provide different kinds of information at a very high spatial resolution, state-of-the-art TEM and related techniques are in the core of this multidisciplinary and rapidly growing field. The first major topic is related to the assessment of local atomic ordering/disordering phenomena in functional materials. A series of rare earth niobates (RE3NbO7) will be studied in order to understand the microstructural origin of their proton conduction properties, that make them excellent candidates to be used as electrode materials in solid oxide fuel cells. Also, single crystals of the tetragonal tungsten bronze (TTB) Sr0.33Ba0.66Nb2O6 (SBN-67) will be studied by different TEM techniques in order to assess the possible short range structural and/or chemical disorder. These features are thought to be responsible for the observed macroscopic uniaxial polarization vector of the material as well as its relaxor properties. A second major topic of interest will be the phenomena taking place at interfaces. This includes the characterization of a set of LaNiO3 perovskite thin films grown on different substrates (LAO, LSAT, STO, YAO). The effect of the substrate-induced compressive/tensile strain, given by lattice mismatch, on the structure of the films will be assessed and related to the observed electric transport properties. The interfaces in a GaN/InAlN multilayered system designed as a Bragg reflector for laser cavities applications will be investigated in order to account for a lower than expected reflectivity of the devices. The presence of structural defects and the detection of intergrowth of wurtzite and zinc blende phases of GaN in thin films will be addressed. Also regarding interfaces and strain conditions, the characterization of the free surface of Nb2O5 nanorods, as a key point for their humidity sensing properties. Expanding on this, the strain state of Nb2O5 when grown on SnO2 nanowires will also be studied. The coupling of the sensing capabilities of Nb2O5 with the electrical transport properties of SnO2 is of particular interest for functional sensing devices. Therefore, defects at the interface and strain state are of capital interest in order to understand the band structure alignment of the system. Interfaces in lower dimensionality systems will also be studied, as in the case of Ag@Fe3O4 dimers for applications in magnetoplasmonics. The epitaxial quality, strain, and the possible chemical diffusion through the contact surface of the two phases of the dimer are key aspects in order to properly tailor their optical properties. The last major topic is the mapping of magnetic fields at the nanoscale. The magnetic configurations of different geometric arrangements of magnetite Fe3O4 nanocubes will be studied. This characterization is aimed at obtaining enhanced responses in magnetic hyperthermia treatments for cancer. Given the strong interrelationship between the problems under study, the chapter structure follows the dimensionality of the systems under study (3D, 2D, 1D and 0D systems)., La reducció en l'escala espacial associada a la revolució de la Nanociència i la Nanotecnologia fa necessari comptar amb una sèrie d'eines capaces d'assolir una resolució sense precedents en una gran varietat d'àress, ja no tan sols com a control de qualitat, sinó per tal d'entendre les propietats de la matèria a la nanoescala. La correlació de la configuració estructural, la composició química i les distribucions de càrrega amb les propietats funcionals és imprescindible pel disseny de nous dispositius, tant des de la perspectiva 'top down' (reducció de les dimensions dels dispositius) com de la perspectiva 'bottom up' (fabricació d'estructures complexes a partir de blocs més petits, fins i tot àtoms). La capacitat de la Microscòpia Electrònica de Transmissió (TEM) de proporcionar diferents tipus d'informació amb una alta resolució espacial, situa les tècniques avançades de TEM com a peça clau en el desenvolupament d'aquest camp multidisciplinari i creixent. L'objectiu principal d'aquesta tesi ha estat l'aplicació de tècniques quantitatives d'imatge TEM per la resolució de problemes en ciència dels materials. La tesi cobreix un espectre ampli pel que fa al tipus de materials estudiats i els seus camps d'aplicació. El Capítol 1 presenta una introducció general a la teoria de formació d'imatge aplicada a la microscopia TEM. S'hi exposen els diferents fenòmens d'interacció electró-matèria que són responsables dels diferents tipus de contrast que es poden trobar a les imatges TEM. El Capítol 2 presenta les tècniques experimentals que es faran servir en la caracterització dels materials, en concret la simulació d'imatges d'alta resolució (HRTEM), l'holografia electrònica i l'anàlisi de la fase geomètrica (GPA). S'hi pot trobar una descripció del marc teòric i dels fonaments experimentals, juntament amb un resum dels resultats més recents en aquests camps. Els resultats experimentals s'agrupen en els capítols posteriors segons la dimensionalitat dels sistemes estudiats. En ordre decreixent de dimensionalitat s'hi inclouen: materials massius (3D), capes primes (2D), nanofils (1D) i nanopartícules (1D).

In cerium oxide nanoparticles, the facets exposed control their reactivity and catalytic behavior and hence their performance in applications such as three-way catalysis, gas sensors, or solid fuel cells. Thus, the precise characterization of the cerium oxide facets exposed is crucial. In the present work, the geometry of branched cerium oxide nanoparticles, obtained by means of ligand-controlled overgrowth, is determined through the comparison between High Resolution Transmission Electron Microscopy (HRTEM) experimental and simulated images. Two possible 3D structures, corresponding to octapod and tetrapod geometries, were suggested from a preliminary examination of the experimental HRTEM images. A comparative analysis of the gray scale intensity profiles of the simulated and experimental HRTEM images was then performed. This method proved capable of discriminating between the two proposed geometries, showing CeO2 nanoparticles to have an octapod geometry. The obtained results were further confirmed by comparing High Angular Dark Field experimental and simulated images of the nanoparticles. This method can be suitable whenever 3D-Tomographic reconstruction is not feasible in the TEM, for instance, in the case of highly beam sensitive materials.

In this work we apply low-loss electron energy loss spectroscopy (EELS) to probe the structural and electronic properties of single silicon nanocrystals (NCs) embedded in three different dielectric matrices (SiO2, SiC and Si(3)N(4)). A monochromated and aberration corrected transmission electron microscope has been operated at 80 kV to avoid sample damage and to reduce the impact of radiative losses. We present a novel approach to disentangle the electronic features corresponding to pure Si-NCs from the surrounding dielectric material contribution through an appropriate computational treatment of hyperspectral datasets. First, the different material phases have been identified by measuring the plasmon energy. Due to the overlapping of Si-NCs and dielectric matrix information, the variable shape and position of mixed plasmonic features increases the difficulty of non-linear fitting methods to identify and separate the components in the EELS signal. We have managed to solve this problem for silicon oxide and nitride systems by applying multivariate analysis methods that can factorize the hyperspectral datacubes in selected regions. By doing so, the EELS spectra are re-expressed as a function of abundance of Si-NC-like and dielectric-like factors. EELS contributions from the embedded nanoparticles as well as their dielectric surroundings are thus studied in a new light, and compared with the dielectric material and crystalline silicon from the substrate. Electronic properties such as band gaps and plasmon shifts can be obtained by a straightforward examination. Finally, we have calculated the complex dielectric functions and the related electron effective mass and density of valence electrons.

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) achieves the hypertrophy of the future liver remnant in seven days. We achieved the same hypertrophy placing a tourniquet in the parenchimal transection line associating a right portal vein ligation (associating liver tourniquet and right portal vein ligation for staged hepatectomy-ALTPS). In perihiliar tumors a«non touch» technique should be performed. ALPPS y ALTPS do not comply with this technical aspect because a dissection of the hilum is carried out in both procedures during the portal dissection. To avoid this problem we devised a new method called sequential ALTPS. It consists of placing a tourniquet in the umbilical fissure without ligation of the right portal vein during the first stage. Subsequently, on the 4(th) postoperative day we perform a percutaneous right portal vein embolization. We present the first case of this new technique in which we have obtained a hypertrophy of 77% of the future liver remnant seven days after portal vein embolization. In the second stage a right trisectionectomy was performed with inferior vena cava resection with a goretex graft replacement.

This study evaluated the effects of N-acetyl-l-cysteine (NAC), a free radical scavenger, and Nω-nitro-l-arginine methyl ester (l-NAME), a nitric oxide (NO) synthesis inhibitor, on the changes in renal function, intrarenal blood flow distribution (laser-Doppler flowmetry), and plasma peroxynitrite levels during the acute renal failure (ARF) produced by inferior vena cava occlusion (IVCO; 45 min) in anesthetized rats. Renal blood flow fell on reperfusion (whole kidney by −45.7%; cortex −58.7%, outer medulla −62.8%, and papilla −47.7%); glomerular filtration rate (GRF) also decreased (−68.6%), whereas fractional sodium excretion (FENa%) and peroxynitrite and NO[Formula: see text]/NO[Formula: see text] plasma levels increased (189.5, 46.5, and 390%, respectively) after ischemia. Pretreatment with l-NAME (10 μg · kg−1· min−1) aggravated the fall in renal blood flow seen during reperfusion (−60%). Pretreatment with NAC (150 mg/kg bolus + 715 μg · kg−1· min−1iv) partially prevented those changes in renal function (GFR only fell by −29.2%, and FENa%increased 119.4%) and laser-Doppler blood flow, especially in the outer medulla, where blood flow recovered to near control levels during reperfusion. These beneficial effects seen in rats given NAC seem to be dependent on the presence of NO, because they were abolished in rats pretreated with l-NAME. Also, the antioxidant effects of NAC prevented the increase in plasma peroxynitrite after ischemia. In conclusion, NAC ameliorates the renal failure and the outer medullary vasoconstriction induced by ICVO, effects that seem to be dependent on the presence of NO and the scavenging of peroxynitrite.

3D single-crystalline, well-aligned GaN-InGaN rod arrays are fabricated by selective area growth (SAG) metal-organic vapor phase epitaxy (MOVPE) for visible-light water splitting. Epitaxial InGaN layer grows successfully on 3D GaN rods to minimize defects within the GaN-InGaN heterojunctions. The indium concentration (In ∼ 0.30 ± 0.04) is rather homogeneous in InGaN shells along the radial and longitudinal directions. The growing strategy allows us to tune the band gap of the InGaN layer in order to match the visible absorption with the solar spectrum as well as to align the semiconductor bands close to the water redox potentials to achieve high efficiency. The relation between structure, surface, and photoelectrochemical property of GaN-InGaN is explored by transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), Auger electron spectroscopy (AES), current-voltage, and open circuit potential (OCP) measurements. The epitaxial GaN-InGaN interface, pseudomorphic InGaN thin films, homogeneous and suitable indium concentration and defined surface orientation are properties demanded for systematic study and efficient photoanodes based on III-nitride heterojunctions.