Short-term outcomes of laparoscopic gastric plication in morbidly obese patients: Importance of postoperative follow-up

Demand for feasible, safe, and preferably low-cost methods of weight reduction is rising every day. The present study reports findings from laparoscopic gastric plication (LGP), which is a new restrictive bariatric technique, combined with a postoperative follow-up program. A 2-year prospective study was performed following LGP in 53 female morbidly obese patients from Gorgan, Iran, with a mean age of 36.3 years and mean body mass index (BMI) of 42.6 kg/m2 (35.3-62.4). Through a four-port approach, the greater omentum and short gastric vessels were transected and the greater curvature was imbricated into the body of the stomach with two rows of nonabsorbable sutures. After surgery, all patients were scheduled to attend a weekly group meeting for behavioral modification and psychotherapy. The mean operative time and hospital stay was 95 min and 72 h, respectively. No intraoperative complications occurred. Mean percentages of excess weight loss (%EWL) were 25.6 %, 54.2 %, 70.2 %, and 74.4 % after 1, 6, 12, and 24 months, respectively. Six patients lost >84 % of their excess weight after 24 months. Patients who did not participate in the group meetings had a lower %EWL after 12 (79.5 % vs. 55.6 %) and 24 months (90 % vs. 43.4 %) compared with the patients who regularly participated in the group meetings (P < 0.005). LGP is a feasible, safe, and effective surgical method for weight loss for at least 24 months when performed on morbidly obese patients. Postoperative group meetings (POGM) for psychotherapy and behavioral modification helped patients to achieve better results. © 2012 Springer Science + Business Media, LLC

A perovskite silver antimicrobial compound with diminished silver ion release

L'infection microbienne est une des causes des maladies menaçant la vie. Elle est conventionnellement traitée par des antibiotiques. Cette pratique a entraîné l'émergence de la résistance aux antimicrobiens (RAM), qui est associée à un taux de mortalité croissant. Afin de contrer le problème, les cellules microbiennes doivent être retirées de la zone de cible sans que l’agent microbienne libère des sous-produits. Les désinfectants, tels que l'eau de Javel et le chlore, tout en étant très efficace à large spectre antimicrobien, ne conviennent pas dans certaines circonstances. Ces composés sont chimiquement réactifs, ils peuvent donc corroder les surfaces en contact et laisser des composés toxiques. D'autre part, les antibiotiques conventionnels, bien qu'ils ne présentent pas ces propriétés indésirables de désinfectants, ont généralement un spectre d'action plus étroit et sont plus sujets au développement du RAM. Entre les désinfectants et les antibiotiques, il existe des composés à base d'argent qui, tout en ayant une activité antimicrobienne à large spectre, sont relativement sans danger pour les cellules de mammifères. Le mécanisme de l'action antimicrobienne des composés d’argent classiques est basé sur la libération d'ions argent dans le milieu. L'argent est un métal coûteux et se dégrade en libérant des ions. De plus, l'exposition à des niveaux élevés d'ions d'argent est un danger pour la santé et l'environnement et donc doit être évitée. Par conséquent, incorporer étroitement des atomes d'argent dans une structure moléculaire résistante à la corrosion, tout en gardant l'activité antimicrobienne, permettrait d'utiliser l'argent comme agent antimicrobien dans des applications exigeant un composé d'argent résistant à la corrosion avec de faibles niveaux de libération d'argent dans l'environnement. Pour atteindre cet objectif, un nouveau composé d'argent, AgNbO3, a été synthétisé et caractérisé en termes de taille, de morphologie, de comportement de sédimentation, de corrosion et d'activité antimicrobienne. Il a été démontré que tout en ayant un taux de libération d'argent diminué de plus de 150 fois par rapport aux particules Ag2O de référence, l'activité antimicrobienne des nanoparticules AgNbO3, quantifiée par la concentration minimale inhibitrice (MIC), était similaire dans le cas des milieux aqueux. L'étude du mécanisme d'action a indiqué que le composé exerce son action antimicrobienne par contact avec des cellules microbiennes.Microbial infections are the main causes of life threatening diseases and are conventionally treated by antibiotic agents. This practice has resulted in the emergence of antimicrobial resistance (AMR), which is associated with ever-increasing rate of mortality. In order to counter the issue, the microbial cells should be removed from targeted areas without releasing toxic byproducts behind. Disinfectants, such as bleach and chlorine, while being very effective broad-spectrum antimicrobial, are not suitable in some circumstances. These compounds are chemically reactive; thus, they can corrode the surfaces in contact and can leave behind toxic compounds particularly in reaction with organic matter. On the other hand, the conventional antibiotics, while not having these undesired properties of disinfectants, have generally narrower spectrum of action and are more prone to the development of AMR. In between of disinfectants and antibiotics there are silver-based compounds, which while having broad-spectrum antimicrobial activity, are relatively safe to mammalian cells. There are, however, some challenges associated with the usage of the conventional silver compounds as antimicrobial agent, arising from the mechanism of antimicrobial action through the release of silver ions to the medium. Silver is an expensive metal and degrades in while releasing ions. Moreover, exposure to high levels of silver ions is a health an environmental hazard and should be avoided. Therefore, tightly incorporating silver atoms in a corrosion-resistant molecular level structure with keeping the antimicrobial activity would enable feasibility of using silver as an antimicrobial agent in applications that require corrosion resistant silver compound with low levels of silver release to the environment. To achieve this goal, a new silver compound, AgNbO3, was synthesized and characterized in terms of its size, morphology, sedimentation behavior, corrosion, and antimicrobial activity. It was demonstrated that while having a diminished silver release rate of more than 150 fold compared to the reference Ag2O particles, the antimicrobial activity of AgNbO3 nanoparticles, quantified by minimum inhibitory concentration (MIC), was similar in the case of aqueous media. Investigating the mechanism of action indicated that the compound exerts its antimicrobial action via contact with microbial cells

The evaluation of ontologies: quality, reuse and social factors

Finding a “good” or the “right” ontology is a growing challenge in the ontology domain, where one of the main aims is to share and reuse existing semantics and knowledge. Before reusing an ontology, knowledge engineers not only have to find a set of appropriate ontologies for their search query, but they should also be able to evaluate those ontologies according to different internal and external criteria. Therefore, ontology evaluation is at the heart of ontology selection and has received a considerable amount of attention in the literature.Despite the importance of ontology evaluation and selection and the widespread research on these topics, there are still many unanswered questions and challenges when it comes to evaluating and selecting ontologies for reuse. Most of the evaluation metrics and frameworks in the literature are mainly based on a limited set of internal characteristics, e.g., content and structure of ontologies and ignore how they are used and evaluated by communities. This thesis aimed to investigate the notion of quality and reusability in the ontology domain and to explore and identify the set of metrics that can affect the process of ontology evaluation and selection for reuse. [Continues.

Electron acceleration in interplanetary space: Radio signatures and in-situ observations

Coronal Mass Ejections (CMEs) are large-scale releases of hot plasma, to which the magnetic field is frozen-in. If the CMEs are faster than the local magnetosonic velocity in the solar wind, they create shock waves as they travel through the corona and Interplanetary (IP) space. Shock waves driven by CMEs can accelerate Solar Energetic Particles (SEPs). Both phenomena involve the acceleration of electrons, which can be observed as electromagnetic radiation and plasma radiation. This doctoral thesis presents analyses of the presence and propagation of accelerated electrons in the IP medium. By utilizing the observations of multiple science satellites, such as STEREO-A, STEREO-B, and Wind, we get a comprehensive picture of the accelerated particles and solar radio bursts, at various wavelengths. We can use this information to determine the origin of the eruptions, their directivity, and connections to other solar events. In particular, the role of shock waves in the acceleration of relativistic electrons is the subject of this research. Earlier studies have already confirmed the role of shock waves in the acceleration of electrons to keV energies using radio bursts, but for the higher energies, the research is still in progress. As a result of observations by many space instruments we now have a 3D view of the Sun, particularly in the analysis of type IV radio bursts in multi-spacecraft radio dynamic spectra. The directivity of radio bursts, i.e., being seen only toward a certain direction, can be explained either by absorption in the surrounding medium or by obstruction of dense plasma region, even by the solar disk itself. The presence of dense plasma regions like solar streamers, in directions where no radiation is visible, strengthens this conclusion. Type II radio bursts can be associated with the interaction of streamers and shock waves. Our analysis of three separate type IV radio bursts revealed that their radiation was not visible toward directions where type II radio bursts were observed. The eruptions were generated by the same active region on three different days, and the location of the eruption region on the Sun changed from the disk center to the solar limb. The directivity of the type IV radio bursts could therefore be explained as absorption in the type II burst regions, as the shock fronts contain higher-density plasma. In the study of isolated type II radio bursts, i.e., when separated from other bursts in time and also in frequency, we found that contrary to the previous studies, the majority of these radio bursts were associated with shocks that were created near the CME leading fronts. The analysis suggests the necessity of special coronal conditions, to form this subgroup of low-frequency type II radio bursts. The creation of relativistic electrons in IP shocks led to the investigation of whether these shocks can continue to accelerate electrons up to one Astronomical Unit (AU). Using in-situ observations of the electron flux, SEP events, and associated Energetic Storm Particle (ESP) occurrences, we identified nine cases observed by High Energy Telescope (HET) onboard STEREO where MeV electrons showed a significant increase associated with shocks driven by fast speed Interplanetary CMEs (ICMEs). We also found that such events were rare at a distance of 1 AU. The research suggests the necessity to make observations with satellites orbiting closer to the Sun, such as the Parker Solar Probe and Solar Orbiter, so that we can find out how electrons are accelerated in IP shocks. Finally, in-situ observations show clear signatures of local acceleration of electrons during the passage of the shock wave or the sheath region of the ICME during the ESP event