Laser-Synthesized 2D-MoS2 Nanostructured Photoconductors.

The direct laser synthesis of periodically nanostructured 2D transition metal dichalcogenide (2D-TMD) films, from single source precursors, is presented here. Laser synthesis of MoS2 and WS2 tracks is achieved by localized thermal dissociation of Mo and W thiosalts, caused by the strong absorption of continuous wave (c.w.) visible laser radiation by the precursor film. Moreover, within a range of irradiation conditions we have observed occurrence of 1D and 2D spontaneous periodic modulation in the thickness of the laser-synthesized TMD films, which in some cases is so extreme that it results in the formation of isolated nanoribbons with a width of ~200 nm and a length of several micrometers. The formation of these nanostructures is attributed to the effect that is known as laser-induced periodic surface structures (LIPSS), which is caused by self-organized modulation of the incident laser intensity distribution due to optical feedback from surface roughness. We have fabricated two terminal photoconductive detectors based on nanostructured and continuous films and we show that the nanostructured TMD films exhibit enhanced photo-response, with photocurrent yield increased by three orders of magnitude as compared to their continuous counterparts.

Revealing the static and dynamic nanomechanical properties of diatom frustules-Nature's glass lace.

Diatoms are single cell microalgae enclosed in silica exoskeletons (frustules) that provide inspiration for advanced hybrid nanostructure designs mimicking multi-scale porosity to achieve outstanding mechanical and optical properties. Interrogating the structure and properties of diatoms down to nanometer scale leads to breakthrough advances reported here in the nanomechanical characterization of Coscinodiscus oculus-iridis diatom pure silica frustules, as well as of air-dried and wet cells with organic content. Static and dynamic mode Atomic Force Microscopy (AFM) and in-SEM nanoindentation revealed the peculiarities of diatom response with separate contributions from material nanoscale behavior and membrane deformation of the entire valve. Significant differences in the nanomechanical properties of the different frustule layers were observed. Furthermore, the deformation response depends strongly on silica hydration and on the support from the internal organic content. The cyclic loading revealed that the average compliance of the silica frustule is 0.019 m/N and increases with increasing number of cycles. The structure-mechanical properties relationship has a direct impact on the vibrational properties of the frustule as a complex micrometer-sized mechanical system. Lessons from Nature's nanostructuring of diatoms open up pathways to new generations of nano- and microdevices for electronic, electromechanical, photonic, liquid, energy storage, and other applications.

Feasibility, safety and predictors of a successful "blind wiring" antegrade approach in the percutaneous treatment of chronic coronary total occlusions.

BACKGROUND: Antegrade wiring using only antegrade guiding catheter without contralateral injection (defined as "blind antegrade wiring") may represent a valid initial treatment strategy for selected chronic coronary total occlusions (CTOs) due to the potentially lower risk of vascular complications. A careful selection of lesions eligible for this strategy as well as an accurate balance between the likelihood of success and failure is paramount. The aim of the study is to determine the rate of successful revascularization, the potential predictors of failure and the incidence of major complications, when using a "blind antegrade wiring" technique. METHODS: In this multicentric study, consecutive patients with CTO undergoing percutaneous coronary intervention (PCI) were retrospectively screened. All cases approached using "blind antegrade wiring" technique were included. RESULTS: Out of 155 consecutive CTO-PCIs, 94 involved initial "blind antegrade wiring" strategy. Successful revascularization by means of "blind antegrade wiring" technique was achieved in 73 (78%) patients. Final successful revascularization was obtained in 19 of the remaining 21 procedures with "blind antegrade wiring" failure using other techniques (by adding a second contralateral guiding catheter; 98% total successful revascularization). Logistic regression analysis identified higher J-CTO Score as the only predictor of "blind antegrade wiring" failure. One complication occurred (wire-based coronary perforation). CONCLUSIONS: "Blind antegrade wiring" may be considered as initial strategy for selected CTO-PCI, mainly for CTOs with low J-CTO Score. This strategy would allow in a substantial number of cases to avoid a priori dual injection, keeping it as secondary strategy in case of "blind antegrade wiring" failure.

A SERS platform based on diatomite modified by gold nanoparticles using a combination of layer-by-layer assembly and a freezing-induced loading method.

Siliceous diatom frustules represent an up-and-coming platform for a range of bio-assisted nanofabrication processes able to overcome the complexity and high cost of current engineering technology solutions in terms of negligibly small power consumption and environmentally friendly processing combined with unique highly porous structures and properties. Herein, the modification of diatomite - a soft, loose, and fine-grained siliceous sedimentary rock composed of the remains of fossilized diatoms - with gold nanoparticles using layer-by-layer technology in combination with a freezing-induced loading approach is demonstrated. The obtained composite structures are characterized by dynamic light scattering, extinction spectroscopy, scanning (SEM) and transmission electron microscopy (TEM), and photoacoustic imaging techniques, and tested as a platform for surface-enhanced Raman scattering (SERS) using Rhodamine 6G. SEM, TEM, and energy dispersive X-ray spectroscopy (EDX) confirmed a dense coating of gold nanoparticles with an average size of 19 nm on the surface of the diatomite and within the pores. The photoacoustic signal excited at a wavelength of 532 nm increases with increasing loading cycles of up to three polyelectrolyte-gold nanoparticle bilayers. The hybrid materials based on diatomite modified with gold nanoparticles can be used as SERS substrates, but also as biosensors, catalysts, and platforms for advanced bioimaging.

FIB-DIC Residual Stress Evaluation in Shot Peened VT6 Alloy Validated by X-ray Diffraction and Laser Speckle Interferometry.

Ga-ion micro-ring-core FIB-DIC evaluation of residual stresses in shot peened VT6 (Ti-6Al-4V) alloy was carried out and cross-validated against other non-destructive and semi-destructive residual stresses evaluation techniques, namely, the conventional sin2ψ X-ray diffraction and mechanical hole drilling. The Korsunsky FIB-DIC method of Ga-ion beam micro-ring-core milling within FIB-SEM with Digital Image Correlation (DIC) deformation analysis delivered spatial resolution down to a few micrometers, while the mechanical drilling of circular holes of ~2 mm diameter with laser speckle interferometry monitoring of strains gave a rough spatial resolution of a few millimeters. Good agreement was also found with the X-ray diffraction estimates of residual stress variation profiles as a function of depth. These results demonstrate that FIB-DIC provides rich information down to the micron scale, it also allows reliable estimation of macro-scale residual stresses.

Biological Safety and Biodistribution of Chitosan Nanoparticles.

: The effect of unmodified chitosan nanoparticles with a size of ~100 nm and a weakly positive charge on blood coagulation, metabolic activity of cultured cardiomyocytes, general toxicity, biodistribution, and reactive changes in rat organs in response to their single intravenous administration at doses of 1, 2, and 4 mg/kg was studied. Chitosan nanoparticles (CNPs) have a small cytotoxic effect and have a weak antiplatelet and anticoagulant effect. Intravenous administration of CNPs does not cause significant hemodynamic changes, and 30 min after the CNPs administration, they mainly accumulate in the liver and lungs, without causing hemolysis and leukocytosis. The toxicity of chitosan nanoparticles was manifested in a dose-dependent short-term delay in weight gain with subsequent recovery, while in the 2-week observation period no signs of pain and distress were observed in rats. Granulomas found in the lungs and liver indicate slow biodegradation of chitosan nanoparticles. In general, the obtained results indicate a good tolerance of intravenous administration of an unmodified chitosan suspension in the studied dose range.

Spontaneous coronary artery dissection during cisplatin and capecitabine therapy.

INTRODUCTION: Spontaneous coronary artery dissection is a rare cardiovascular disease that can cause acute myocardial infarction and sudden cardiac death. The mechanism of this pathology and the optimal treatment are not fully understood. PRESENTATION OF CASE: An acute myocardial infarction developed while a fifty five years old woman with a rectal adenocarcinoma was receiving a cisplatin and capecitabine therapy. Coronary angiography demonstrated a multivessel occlusion of coronary arteries. DISCUSSION: The authors discuss several factors that may lead to the spontaneous coronary artery dissection including chemotherapy-induced vasospasm. Chemotherapy based on the cisplatin and capecitabine intake can cause a cardiotoxic effect. CONCLUSION: Thus, spontaneous coronary artery dissection is a disease with an extremely complex etiololy, which does not have a special treatment guide. Management should be considered individually for each case.