Ions in the Deep Subsurface of Earth,Mars, and Icy Moons: Their Effects in Combination with Temperature and Pressure on tRNA–Ligand Binding

The interactions of ligands with nucleic acids are central to numerous reactions in the biological cell. How such reactions are affected by harsh environmental conditions such as low temperatures, high pressures, and high concentrations of destructive ions is still largely unknown. To elucidate the ions’ role in shaping habitability in extraterrestrial environments and the deep subsurface of Earth with respect to fundamental biochemical processes, we investigated the effect of selected salts (MgCl₂, MgSO₄, and Mg(ClO₄)₂) and high hydrostatic pressure (relevant for the subsurface of that planet) on the complex formation between tRNA and the ligand ThT. The results show that Mg²⁺ salts reduce the binding tendency of ThT to tRNA. This effect is largely due to the interaction of ThT with the salt anions, which leads to a strong decrease in the activity of the ligand. However, at mM concentrations, binding is still favored. The ions alter the thermodynamics of binding, rendering complex formation that is more entropy driven. Remarkably, the pressure favors ligand binding regardless of the type of salt. Although the binding constant is reduced, the harsh conditions in the subsurface of Earth, Mars, and icy moons do not necessarily preclude nucleic acid–ligand interactions of the type studied here.     

Growth of Ag, Au, Cu, and Pt nanostructures on surfaces by micropatterned laser-image formations

Silver, gold, copper and platinum nanoparticles (NPs) were grown on surfaces in the form of patterns by the exposure of laser radiation onto droplets of metal ion solutions and the aid of a reducing agent. The generation of patterns from metallic NPs was achieved by combining induced growth of NPs and nanostructures by laser incidence directly on surfaces and optical image formation techniques for transferring the patterns. Near-UV (363.8 nm) and visible (532 nm) laser wavelengths were used for the laser-induced growth of NPs into microstructures on glass, quartz, stainless steel, silicon, and gold-on-silicon substrates. The sizes of the patterns formed were on the micrometer scale and the sizes of the transferred patterns were on the millimeter scale. The patterns formed were generated by optical transference of image and interference of laser beams. Ag and Au substrates were highly active in surface enhanced Raman spectroscopy (SERS). The enhanced Raman activity was measured for SERS probe molecules: 9H-purin-6-amine (adenine) and 1,2-bis (4-pyridyl)-ethane analytes on Ag and Au substrates, respectively. The enhancement factors obtained were 1.8×10(5) and 6.2×10(6), respectively.     

Update on the Diagnostic Pitfalls of Autopsy and Post-Mortem Genetic Testing in Cardiomyopathies

Inherited cardiomyopathies are frequent causes of sudden cardiac death (SCD), especially in young patients. Despite at the autopsy they usually have distinctive microscopic and/or macroscopic diagnostic features, their phenotypes may be mild or ambiguous, possibly leading to misdiagnoses or missed diagnoses. In this review, the main differential diagnoses of hypertrophic cardiomyopathy (e.g., athlete’s heart, idiopathic left ventricular hypertrophy), arrhythmogenic cardiomyopathy (e.g., adipositas cordis, myocarditis) and dilated cardiomyopathy (e.g., acquired forms of dilated cardiomyopathy, left ventricular noncompaction) are discussed. Moreover, the diagnostic issues in SCD victims affected by phenotype-negative hypertrophic cardiomyopathy and the relationship between myocardial bridging and hypertrophic cardiomyopathy are analyzed. Finally, the applications/limits of virtopsy and post-mortem genetic testing in this field are discussed, with particular attention to the issues related to the assessment of the significance of the genetic variants.     

A review of phosphorescent and fluorescent phosphors for fingerprint detection

Currently, the efficient detection of fingerprints is essential for the crime investigations. Revealing fingerprints is commonly achieved with fluorescent organic compounds but they are not efficient for fingerprint detection on porous or reflective surfaces. In order to solve the problem of collecting fingerprints on porous/reflective surfaces, inorganic phosphors have been employed, since they have characteristics of variable color emission, afterglow, high chemical stability and nano-size, which allow the fingerprint detection on any porous or non-porous surfaces. Due to these last properties, this review presents a summary about the use of phosphorescent and fluorescent phosphors for the detection of latent fingerprints. First, we discussed the main physical and chemical characteristics of the fingerprints which permit their detection and collection from any surface. After this, we presented the main morphological, structural and luminescent properties of the phosphorescent and fluorescent phosphors that allow their use for fingerprint detection. Later, we demonstrated with pictures of fingerprints (with and without light emission from the phosphors deposited on them) that both, phosphorescent and fluorescent phosphors can be used to visualize fingerprints with high resolution and high contrast without interference of the background surface, which is ideal for its collection and registration in the Automated Fingerprint Identification System (AFIS). We believe that this review could be useful to understand how to select an appropriate phosphorescent or fluorescent material for fingerprint detection depending on the type of surface (porous or non-porous, reflective or not reflective) where the fingerprint is deposited.     

Enhancing the hydrogen generation of TiO2 nanoparticles by decorating its surface with BiI3 and PbI2 quantum dots

This work reports the performance of TiO₂/BiI₃ and TiO₂/PbI₂ nanocomposites for hydrogen generation. BiI₃ and PbI₂ quantum dots (QDs) were grown on TiO₂ (P25 Degussa) using a fast injection method. According to the analysis by X-ray diffraction, the nanocomposites have a mixture of anatase, rutile and cubic phases from TiO₂, BiI₃ and PbI₂. The images obtained from transmission electron microscopy revealed that the TiO₂ support have sizes in the range of 70–220 nm while the QDs of BiI₃ and PbI₂ (co-catalysts) grown on TiO₂ have sizes in the range of 12–17 nm. The presence of these iodides on TiO₂ created oxygen vacancies defects (confirmed by photoluminescence measurements) that extended the light absorption of TiO₂ from the UV to the VIS range. According to the results from the photocatalytic experiments for hydrogen generation (achieved using pure water and UV-VIS light), the hydrogen generation rates produced by the TiO₂/BiI₃ and TiO₂/PbI₂ nanocomposites were 437–580 times, 81–108 times and 21–30 times, higher than these for pure TiO₂, PbI₂ and BiI₃, respectively. The maximum hydrogen generation rates of the TiO₂/BiI₃ and TiO₂/PbI₂ nanocomposites were 290.7 and 219.2 μmol h^?1 g^?1, respectively. In addition, the TiO₂/BiI₃ and TiO₂/PbI₂ nanocomposites contained defects that acted as electron trapping centers, which in turn, delayed the electron-hole recombination and this favored the photocatalytic generation of H₂. Moreover, the heterojunction formed between the TiO₂ and the iodides allowed the transfer of electrons from the conduction band of TiO₂ toward the conduction band of the iodides, creating a “sink” for the electrons which delayed the electron hole recombination. The results presented here demonstrated that the deposition of iodide co-catalyst on TiO₂ is a feasible option to enhance the hydrogen generation.     

Melatonin and Myo-Inositol: Supporting Reproduction from the Oocyte to Birth

Human pregnancy is a sequence of events finely tuned by several molecular interactions that come with a new birth. The precise interlocking of these events affecting the reproductive system guarantees safe embryo formation and fetal development. In this scenario, melatonin and myo-inositol seem to be pivotal not only in the physiology of the reproduction process, but also in the promotion of positive gestational outcomes. Evidence demonstrates that melatonin, beyond the role of circadian rhythm management, is a key controller of human reproductive functions. Similarly, as the most representative member of the inositol’s family, myo-inositol is essential in ensuring correct advancing of reproductive cellular events. The molecular crosstalk mediated by these two species is directly regulated by their availability in the human body. To date, biological implications of unbalanced amounts of melatonin and myo-inositol in each pregnancy step are growing the idea that these molecules actively contribute to reduce negative outcomes and improve the fertilization rate. Clinical data suggest that melatonin and myo-inositol may constitute an optimal dietary supplementation to sustain safe human gestation and a new potential way to prevent pregnancy-associated pathologies.     

A new purification technique for single-walled carbon nanotubes by interaction with alkali and oxygen

In this work we present a purification technique for oxygen removal from carbon nanotubes (CNTs) at relatively low temperature monitored by X-ray Photoelectron Spectroscopy and electrical characterization (change in resistance). We dope the sample with alkali metal (Na, K and Cs), which successively bind with the residual impurities of oxygen. The removal of the so formed oxides occur by heating the sample at relatively low temperatures (500-600 degrees C) without collateral damage to CNTs mat. In particular we investigate the in situ intercalation of alkali in SWNT followed by oxygen adsorption monitored by DC resistance measurements and X-ray photo-spectroscopy (XPS), demonstrating that the alkali intercalation in the samples trigger the oxygen adsorption. A subsequent sample heating at 500 degrees C removes both oxygen and alkali. Furthermore, the amount of the oxygen removal depends upon the deposited alkali species: in effect only with Na and K we obtain a complete oxygen removal, while other alkalis probably do not intercalate properly inside the nanotube walls. We hypothesize that the atomic radius of alkali can affect the intercalation properties of them inside the CNT structure.