Just as periscopes allow a submarine to visually search for objects above the surface of the sea, in a reversed periscope fashion electrospray mass spectrometry (ESI‐MS) can analyze the compounds at ...the gas phase/liquid phase interface for chemical entities which may exist in solution. The challenge is the identification and structural characterization of key elusive reaction intermediates in chemical transformations, intermediates which are able to explain how chemical processes occur. This Minireview summarizes recent selected publications on the use of ESI‐MS techniques for studying solution intermediates of homogeneous chemical reactions.
Periscope depth: Electrospray mass spectrometry (ESI‐MS) is a powerful tool for studying reaction mechanisms. The reverse‐periscope concept is proposed to exemplify the potential of ESI‐MS to analyze the gas/liquid interface and identify reaction intermediates present in solution. Mechanisms of complex reactions, such as multicomponent reactions, organocatalyzed reactions, and homogeneous metal catalysis, can be studied in detail.
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.
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.
Bioelectrical variations trigger different cell responses, including migration, mitosis, and mutation. At the tissue level, these actions result in phenomena such as wound healing, proliferation, and ...pathogenesis. Monitoring these mechanisms dynamically is highly desirable in diagnostics and drug testing. However, existing technologies are invasive: either they require physical access to the intracellular compartments, or they imply direct contact with the cellular medium. Here, we present a novel approach for the passive recording of electrical signals from non-excitable cells adhering to 3D microelectrodes, based on optical mirroring. Preliminary results yielded a fluorescence intensity output increase of the 5,8% in the presence of a HEK-293 cell on the electrode compared to bare microelectrodes. At present, this technology may be employed to evaluate cell–substrate adhesion and monitor cell proliferation. Further refinements could allow extrapolating quantitative data on surface charges and resting potential to investigate the electrical phenomena involved in cell migration and cancer progression.
Background
Hiatal hernia (HH) repair during laparoscopic sleeve gastrectomy (LSG) has been advocated to reduce the incidence of postoperative gastroesophageal reflux disease (GERD) and/or ...intrathoracic migration (ITM). The necessity of intraoperative repair in asymptomatic patients is still controversial. Previous, mid-term results of a prospective, comparative study evaluating posterior cruroplasty concomitant with LSG (group A 48 patients with simple vs. group B 48 reinforced with bioabsorbable mesh) confirmed the safety and effectiveness of simultaneous procedures. Present aim was to report the 60 months follow-up update, evaluating GERD and esophageal lesions’ incidence and HH’s recurrence.
Results
Follow-up was completed in 87.5% of the patients. Recurrent GERD was registered in 6/38 (15.7%, group A) and in 9/46 (19.5%, group B) (
p
= 1.0000). Grade A esophagitis and GERD was shown in 2 patients (5.2%), respectively 2 (4.3%) of each group (
p
= 1.0000), and recurrent HH was confirmed subsequently by contrast study and CT scan. Neither Barrett’s lesions nor de novo GERD was found in any patient. Failure of the cruroplasty with ITM was recorded in 7 patients from group A (18.4%) and 2 patients from group B (4.3%)
p
< 0.05; hence, a repeat posterior, reinforced cruroplasty was performed in all cases. A total of 12 patients (14.2%, 8 respective 4) were converted within 5 years for persistent/recurrent GERD, with only 1 case of de novo (group B).
Conclusions
Accurate patient selection and proper sleeve technique, combined with posterior cruroplasty (simple or reinforced) ensure effectiveness, with a rate of failure (HH recurrence) at 5 years of 10.7%.
Thermoplasmonics is a method for increasing temperature remotely using focused visible or infrared laser beams interacting with plasmonic nanoparticles. Here, local heating induced by mid-infrared ...quantum cascade laser illumination of vertical gold-coated nanoantenna arrays embedded into polymer layers is investigated by infrared nanospectroscopy and electromagnetic/thermal simulations. Nanoscale thermal hotspot images are obtained by a photothermal scanning probe microscopy technique with laser illumination wavelength tuned at the different plasmonic resonances of the arrays. Spectral analysis indicates that both Joule heating by the metal antennas and surface-enhanced infrared absorption (SEIRA) by the polymer molecules located in the apical hotspots of the antennas are responsible for thermoplasmonic resonances, that is, for strong local temperature increase. At odds with more conventional planar nanoantennas, the vertical antenna structure enables thermal decoupling of the hotspot at the antenna apex from the heat sink constituted by the solid substrate. The temperature increase was evaluated by quantitative comparison of data obtained with the photothermal expansion technique to the results of electromagnetic/thermal simulations. In the case of strong SEIRA by the CO bond of poly-methylmethacrylate at 1730 cm–1, for focused mid-infrared laser power of about 20 mW, the evaluated order of magnitude of the nanoscale temperature increase is of 10 K. This result indicates that temperature increases of the order of hundreds of K may be attainable with full mid-infrared laser power tuned at specific molecule vibrational fingerprints.
This review highlights the recent research advances in active nanostructured anode materials for the next generation of Li-ion batteries (LIBs). In fact, in order to address both energy and power ...demands of secondary LIBs for future energy storage applications, it is required the development of innovative kinds of electrodes. Nanostructured materials based on carbon, metal/semiconductor, metal oxides and metal phosphides/nitrides/sulfides show a variety of admirable properties for LIBs applications such as high surface area, low diffusion distance, high electrical and ionic conductivity. Therefore, nanosized active materials are extremely promising for bridging the gap towards the realization of the next generation of LIBs with high reversible capacities, increased power capability, long cycling stability and free from safety concerns. In this review, anode materials are classified, depending on their electrochemical reaction with lithium, into three groups: intercalation/de-intercalation, alloy/de-alloy and conversion materials. Furthermore, the effect of nanoscale size and morphology on the electrochemical performance is presented. Synthesis of the nanostructures, lithium battery performance and electrode reaction mechanisms are also discussed. To conclude, the main aim of this review is to provide an organic outline of the wide range of recent research progresses and perspectives on nanosized active anode materials for future LIBs.
•Recent progress of nanosized active anode materials has been reviewed.•Shape and size control of nanosized active materials.•Improved specific capacity, cycle life and rate capability of active materials.•Anodes with conductive matrices showing superior rate capability and cyclability.
Tailored hydrophobic and oleophobic surfaces are exploited for controlling the wetting behaviour and evaporation process of solution dropped on them. This enables molecules and nano‐objects that are ...dissolved in water or organic solvents to be delivered and arranged in a well‐defined 2D layout.
Abstract Statement of problem Contemporary pressable and computer-aided design/manufacturing (CAD/CAM) ceramics exhibit good mechanical and esthetic properties. Their wear resistance compared with ...human enamel and traditional gold based alloys needs to be better investigated. Purpose The purpose of this in vitro study was to compare the 2-body wear resistance of human enamel, gold alloy, and 5 different dental ceramics, including a recently introduced zirconia-reinforced lithium silicate ceramic (Celtra Duo). Material and methods Cylindrical specimens were fabricated from a Type III gold alloy (Aurocast8), 2 hot pressed ceramics (Imagine PressX, IPS e.max Press), 2 CAD/CAM ceramics (IPS e.max CAD, Celtra Duo), and a CAD/CAM feldspathic porcelain (Vitablocs Mark II) (n=10). Celtra Duo was tested both soon after grinding and after a subsequent glaze firing cycle. Ten flat human enamel specimens were used as the control group. All specimens were subjected to a 2-body wear test in a dual axis mastication simulator for 120 000 loading cycles against yttria stabilized tetragonal zirconia polycrystal cusps. The wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm3 ). Antagonist wear (mm) was also recorded. Data were statistically analyzed with 1-way ANOVA tests (α=.05). Results The wear depth (0.223 mm) of gold alloy was the closest to that of human enamel (0.217 mm), with no significant difference ( P >.05). The greatest wear was recorded on the milled Celtra Duo (wear depth=0.320 mm), which appeared significantly less wear resistant than gold alloy or human enamel ( P <.05). Conclusions The milled and not glazed Celtra Duo showed a small but significantly increased wear depth compared with Aurocast8 and human enamel. Wear depth and volumetric loss for the glaze-fired Celtra Duo and for the other tested ceramics did not statistically differ in comparison with the human enamel.
The mechanism of the CuAAC reaction has been investigated by electrospray ionization mass spectrometry (ESI‐MS) using a combination of the neutral reactant approach and the ion‐tagging strategy. ...Under these conditions, for the first time, putative dinuclear copper intermediates were fished out and characterized by ESI(+)‐MS/MS. New insight into the CuAAC reaction mechanisms is provided and a catalytic cycle is proposed.
Mechanistic aspects of the CuAAC reaction have been clarified by electrospray ionization mass spectrometry (ESI‐MS). Dinuclear copper intermediates have been detected for the first time and characterized. Neutral and ion‐tagged reactants provided complementary evidence for the reaction catalytic cycle.
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