Persistent Fistula after Sleeve Gastrectomy: A Chronic Dilemma.

Background: There is no time limit for the occurrence of leaks after sleeve gastrectomy LSG, and very late ones might evolve versus persistent, chronic fistulas. The aim of this retrospective study was to analyze the incidence, treatment and outcomes of persistent, chronic fistulas occurred or treated in a bariatric Center of Excellence IFSO-EC (CoE) and to establish a standardized approach. Materials Methods: between 2011-2018, nine cases of postoperative leaks occurred on a total of 1365 LSG performed (0.65%), 7 of them having late presentations (onset over 10 days postoperative). Chronic, persistent fistulas were identified and analyzed, including one gastro-bronchial and one gastro-cutaneous fistulas. Results: We present three peculiar cases of very late, chronic type III fistulas, with onset at 6-84 months after primary LSG and their management, including conservative, interventional radiology and endoscopy and surgical therapies. Conclusions: the management of late, chronic type III fistula is variable, with no standard algorithm to follow, but it should be planned based on the clinical evaluation, time of diagnosis, available resources, multidisciplinary approach and expertise. This emphasises again the necessity of a bariatric CoE that can guarantee a better diagnose and treatment, based on the use of wide, available resources, both professional and material.

Combination of scanning probe technology with photonic nanojets.

Light focusing through a microbead leads to the formation of a photonic nanojet functional for enhancing the spatial resolution of traditional optical systems. Despite numerous works that prove this phenomenon, a method to appropriately translate the nanojet on top of a region of interest is still missing. Here, by using advanced 3D fabrication techniques we integrated a microbead on an AFM cantilever thus realizing a system to efficiently position nanojets. This fabrication approach is robust and can be exploited in a myriad of applications, ranging from microscopy to Raman spectroscopy. We demonstrate the potential of portable nanojets by imaging different sub-wavelength structures. Thanks to the achieved portability, we were able to perform a detailed optical characterization of the resolution enhancement induced by the microbead, which sheds light into the many contradictory resolution claims present in literature. Our conclusions are strongly supported by rigorous data analysis and by numerical simulations, all in perfect agreement with experimental results.

Just Add Salt: A Mass Spectrometric Analysis Method for Imaging Anion-Exchanged Poly(Ionic Liquid)s.

We report the first mass spectrometric analysis of poly(ionic liquid)s (PILs) containing weakly coordinating anions introduced by a fast, simple, and quantitative postmodification method on the example of the hydrophilic, well-defined poly(vinylbenzylpyridinium chloride) p([VBPy]Cl) species, analyzed with an in-source collision induced dissociation-Orbitrap mass spectrometry (MS) protocol. Using the MS approach allows for the precise structural elucidation of ion-exchanged p([VBPy]Cl) utilizing AgX (X = NO3- , CF3 CO2- , BF4- ) salts. The anion exchange is shown to be quantitative - without observing residual chlorinated PIL - on rapid time scales, using only filtration as a standard procedure during sample preparation. In addition, the influence of weakly coordinating anions on the ionization behavior of PILs is studied in detail.

Molding of Plasmonic Resonances in Metallic Nanostructures: Dependence of the Non-Linear Electric Permittivity on System Size and Temperature.

In this paper, we review the principal theoretical models through which the dielectric function of metals can be described. Starting from the Drude assumptions for intraband transitions, we show how this model can be improved by including interband absorption and temperature effect in the damping coefficients. Electronic scattering processes are described and included in the dielectric function, showing their role in determining plasmon lifetime at resonance. Relationships among permittivity, electric conductivity and refractive index are examined. Finally, a temperature dependent permittivity model is presented and is employed to predict temperature and non-linear field intensity dependence on commonly used plasmonic geometries, such as nanospheres.

Investigation by solid-phase microextraction and gas chromatography/mass spectrometry of trail pheromones in ants.

The Dufour's gland content of workers of two ant species of the genus Messor has been analyzed by solid-phase microextraction and gas chromatography with mass spectrometry (GC/MS). The structures of the compounds in the pheromonal mixtures have been determined. In both cases only one intact gland, inserted in a properly dimensioned capillary vial, is sufficient to produce a clean and fully interpretable GC/MS profile. It is worth noting that, for the first time in Messor ants, farnesol has been detected as a minor component of glandular secretion in Messor capitatus.