Recent Developments in Surgery Minimally Invasive Approaches for Patients Requiring Pancreaticoduodenectomy

Over the past decade, minimally invasive surgery has been introduced as a means to allow manipulation of delicate tissues with outstanding visualization of the surgical field. The purpose of this article is to review the available literature regarding early postoperative outcomes and the technical challenges of minimally invasive pancreaticoduodenectomy, including robotic techniques. Herein, we provide a retrospective review of all published studies in the English literature in which a minimally invasive pancreaticoduodenectomy was performed. The reported advantages of minimally invasive pancreaticoduodenectomy include better visualization, faster recovery time, and decreased length of hospital stay. In cases of robotic approaches, some of the proposed advantages include increased dexterity and a superior ergonomic position for the operating surgeon. To our knowledge, few studies have reported results comparable to open techniques in oncologic outcomes with regard to the number of lymph nodes resected and clear margins obtained. An increasing number of pancreatic resections are being performed using minimally invasive approaches. It remains to be determined if the benefits of this technique outweigh its longer operative times and higher costs

Pre- and intraoperative variables affecting early outcomes in elderly patients undergoing pancreaticoduodenectomy

AbstractBackgroundConflicting data exist regarding the safety of pancreatic resections in elderly patients. In this study we compared early complication and mortality rates between patients younger and older than 80 years of age who underwent pancreaticoduodenectomy using a validated national database.MethodsThe National Surgical Quality Improvement Program (NSQIP) database for 2005–2009 was used for this retrospective analysis. The primary outcome measures for our analysis were 30-day postoperative mortality, major complication rate and overall complication rate.ResultsA total of 6293 patients who underwent PD for any cause were included in the analysis. Of these, 9.4% were aged ≥80 years. The incidence of 30-day mortality was significantly higher in patients aged ≥80 years (6.3%) than in those aged <80 years (2.7%). Older patients were also noted to have higher rates of overall complications and serious complications. On multivariate analysis, age, ASA (American Society of Anesthesiologists) classification, reduced functional status, history of dyspnoea, and need for intraoperative transfusion were risk factors associated with the occurrence of overall complications, serious complications and postoperative mortality.ConclusionsThis study shows that age among other factors is a determinant of postoperative morbidity and mortality following PD

MODERN MINING GEOSTATISTICS - CONVENTION WITH CODELCO YEAR 10 (2015) - ANNIVERSARY REPORT

During the 10th year of the convention between CODELCO and the Ecole des Mines of Paris, effort has been made to promote the work done the last two years by attending four congresses in three countries (Chile, France, Germany), two presentations being made by engineers of Codelco.This anniversary report is presented as a catalog containing the papers and the relevant oral presentations with comments. This report is not confidential and can be distributed in the good will of managers and engineers. Topics are :1 Geostatistical comparison between blast and drill holes in a porphyry copper deposit (Sampling congress 2015, Bordeaux, France)2 Diamond Drill Holes, Blast Holes & Cokriging (Mine-Planning 2015, Antofagasta, Chile)3 Anisotropy of the Rock Quality Designation (RQD) & its Geostatistical Evaluation (Geomin 2015, Antofagasta, Chile)4 Geostatistical Evaluation of Rock-Quality Designation and its link with Linear Fracture Frequency (IAMG 2015, Freiberg, Germany)5 Breccia Pipe Prediction: a new approach using non-stationary covariance (IAMG 2015, Freiberg, Germany

Distinctive dielectric properties of nematic liquid crystal dimers

We provide an overview of the effect of the molecular structure on the dielectric properties of dimers exhibiting nematic and twist-bend nematic phases with special focus on how the conformational distribution changes are reflected by the dielectric behaviour. Nematic dimers show distinctive dielectric properties which differ from those of archetypical nematic liquid crystals, as for example, unusual temperature dependence of the static permittivity or dielectric spectra characterised by two low-frequency relaxation processes with correlated strengths. The interpretation of such characteristic behaviour requires that account is taken of the effect of molecular flexibility on the energetically favoured molecular shapes. The anisotropic nematic interactions greatly influence the conformational distribution. Dielectric behaviour can be used to track those conformational changes due to dependence of the averaged molecular dipole moment on the averaged molecular shape. Results for a number of dimers are compared and analysed on the basis of the influence of details of the molecular structure, using a recently developed theory for the dielectric properties of dimers.Postprint (author's final draft

Occular complications following dental local anesthesia

Objective: To determine the frequencyof appearance and the factors most commonlyassociated with ocular complications following dental local anesthesia, also establishing the location and type of anesthesia used. StudyDesign: An indexed search in the Pubmed and Compludoc databases was carried out with the keywords "oral anesthesia", "ocular", "ophthalmologic", "damage", "complications", "injection". We established a limitation that the literature had to have been published after the year 1970. A total of 19 articles were obtained, forming a total sample of 37 patients. The patient's sex, age, nerve anesthetized, type of anesthetic used, ophthalmological complication present, recoverytime, treatment and side effects were analyzed. Results: There is a higher involvement of females (77%). The average age was 34.2 years. There was no preference for an anesthetic technique. Diplopia was the most common complication (65%), which coincides with the data fromother authors. Almost all of the complications were of a temporarynature, with an average recoverytime of 68 minutes. Conclusions: This is one of the few studies of its kind in dental literature, it thus being difficult to make precise conclusions. Ophthalmological complications are seldoma problem, diplopia being the most common among them. The authors appear to indicate an intravascular injection of the anesthetic as the cause of the problem, and therefore, it should be avoided in order to prevent accidents at the ocular level. © Medicina Oral

Structure and magnetism of Tm atoms and monolayers on W(110)

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).We investigated the growth and magnetic properties of Tm atoms and monolayers deposited on a W(110) surface using scanning tunneling microscopy and x-ray magnetic circular and linear dichroism. The equilibrium structure of Tm monolayer films is found to be a strongly distorted hexagonal lattice with a Moiré pattern due to the overlap with the rectangular W(110) substrate. Monolayer as well as isolated Tm adatoms on W present a trivalent ground-state electronic configuration, contrary to divalent gas phase Tm and weakly coordinated atoms in quench-condensed Tm films. Ligand field multiplet simulations of the x-ray absorption spectra further show that Tm has a |J=6,Jz=±5¿ electronic ground state separated by a few meV from the next lowest substates |J=6,Jz=±4¿ and |J=6,Jz=±6¿. Accordingly, both the Tm atoms and monolayer films exhibit large spin and orbital moments with out-of-plane uniaxial magnetic anisotropy. X-ray magnetic dichroism measurements as a function of temperature show that the Tm monolayers develop antiferromagnetic correlations at about 50 K. The triangular structure of the Tm lattice suggests the presence of significant magnetic frustration in this system, which may lead to either a noncollinear staggered spin structure or intrinsic disorder.This work was supported by the European Research Council (StG 203239 NOMAD), Agència de Gestió d’Ajuts Universitaris i de Recerca (2009 SGR 695), Spanish MINECO (Grants No. MAT2009-10040, No. MAT2010-15659, and No. MAT2012-31309), Gobierno de Aragón (Grant No. E81), Fondo Social Europeo, and the Swiss Competence Centre for Materials Science and Technology (CCMX).Peer Reviewe

Molecular dynamics of a binary mixture of twist-bend nematic liquid crystal dimers studied by dielectric spectroscopy

We report a comprehensive dielectric characterization of a liquid crystalline binary mixture composed of the symmetric mesogenic dimer CB7CB and the nonsymmetric mesogenic dimer FFO9OCB. In addition to the high-temperature nematic phase, such a binary mixture shows a twist-bend nematic phase at room temperature which readily vitrifies on slow cooling. Changes in the conformational distribution of the dimers are reflected in the dielectric permittivity and successfully analyzed by means of an appropriate theoretical model. It is shown that the dielectric spectra of the mixture reflect the different molecular dipole properties of the components, resembling in the present case the characteristic dielectric spectra of nonsymmetric dimers. Comparison of the nematic and twist-bend nematic phases reveals that molecular dynamics are similar despite the difference in the molecular environment.Postprint (author's final draft

Miscibility studies of two twist-bend nematic liquid crystal dimers with different average molecular curvatures. A comparison between experimental data and predictions of a Landau mean-field theory for the NTB-N phase transition

We report a calorimetric study of a series of mixtures of two twist-bend liquid crystal dimers, the 1'',7''-bis(4-cyanobiphenyl)-4'-yl heptane (CB7CB) and 1''-(2',4-difluorobiphenyl-4'-yloxy)-9''-(4-cyanobiphenyl-4'-yloxy) nonane (FFO9OCB), the molecules of which have different effective molecular curvatures. High-resolution heat capacity measurements in the vicinity of the NTB-N phase transition for a selected number of binary mixtures clearly indicate a first order NTB-N phase transition for all the investigated mixtures, the strength of which decreases when the nematic range increases. Published theories predict a second order NTB-N phase transition, but we have developed a self-consistent mean field Landau model using two key order parameters: A symmetric and traceless tensor for the orientational order and a short-range vector field which is orthogonal to the helix axis and rotates around of the heliconical structure with an extremely short periodicity. The theory, in its simplified form, depends on two effective elastic constants and explains satisfactorily our heat capacity measurements and also predicts a first-order NTB-N phase transition. In addition, as a complementary source of experimental measurements, the splay (K1) and bend (K3) elastic constants in the conventional nematic phase for the pure compounds and some selected mixtures have been determined.Postprint (author's final draft