Memory Effects in High-Dimensional Systems Faithfully Identified by Hilbert–Schmidt Speed-Based Witness

A witness of non-Markovianity based on the Hilbert–Schmidt speed (HSS), a special type of quantum statistical speed, has been recently introduced for low-dimensional quantum systems. Such a non-Markovianity witness is particularly useful, being easily computable since no diagonalization of the system density matrix is required. We investigate the sensitivity of this HSS-based witness to detect non-Markovianity in various high-dimensional and multipartite open quantum systems with finite Hilbert spaces. We find that the time behaviors of the HSS-based witness are always in agreement with those of quantum negativity or quantum correlation measure. These results show that the HSS-based witness is a faithful identifier of the memory effects appearing in the quantum evolution of a high-dimensional system with a finite Hilbert space.     

Direct fabrication and IV characterization of sub-surface conductive channels in diamond with MeV ion implantation

In the present work we report about the investigation of the conduction mechanism of sp² carbon micro-channels in single crystal diamond. The structures are fabricated with a technique which employs a MeV focused ion-beam to damage diamond in conjunction with variable thickness masks. This process changes significantly the structural properties of the target material, because the ion nuclear energy loss induces carbon conversion from sp³ to sp² state mainly at the end of range of the ions (few micrometers). Furthermore, placing a mask with increasing thickness on the sample it is possible to modulate the channels depth at their endpoints, allowing their electrical connection with the surface. A single-crystal HPHT diamond sample was implanted with 1.8 MeV He⁺ ions at room temperature, the implantation fluence was set in the range 2.1×10¹⁶-6.3×10¹⁷ ions cm^-2, determining the formation of micro-channels with a graded level of damage extending down to a depth of about 3 μm. After deposition of metallic contacts at the channels’ endpoints, the electrical characterization was performed measuring the I-V curves at variable temperatures in the 80-690 K range. The Variable Range Hopping model was used to fit the experimental data in the ohmic regime, allowing the estimation of characteristic parameters such as the density of localized states at the Fermi level. A value of 5.5×10¹⁷ states cm^-3 eV^-1 was obtained, in satisfactory agreement with values previously reported in literature. The power-law dependence between current and voltage is consistent with the space charge limited mechanism at moderate electric fields.     

Endemic infrared divergences in QED3 at finite temperature

We demonstrate that massless QED in three dimensions contains endemic infrared divergences. It is argued that these divergences do not affect observables; furthermore, it is possible to choose a gauge that renders the theory finite.     

On the cryogenic magnetic transition and martensitic transformation of the austenite phase of 7MoPLUS duplex stainless steel

The magnetic behaviour and martensitic transformation at cryogenic temperatures (down to 4 K) of the austenite phase of the duplex stainless steel (DSS), 7MoPLUS, were studied. As regards the prediction of Neel temperature, the empirical expressions for austenitic stainless steels are not applicable to the austenite phase of 7MoPLUS, although the composition of the austenite phase falls within the composition ranges within which the expressions were developed. Regarding the prediction of martensitic point Ms, the applicability of ‘old’ and recently developed expressions has been examined. The recently developed expressions, which take into account more alloying elements and their interactions, are not suitable for the austenite phase of 7MoPLUS. But for the ‘old’, simpler expressions, they seem to be valid in the sense that they all predict high stability of the austenite phase. Results obtained from 7MoPLUS were qualitatively the same as those obtained from another DSS, designated as 2205. Reasons for the applicability and inapplicability of these empirical expressions are suggested.     

Base-induced photorearrangements from 3-styrylfurans to 2-methylnaphthalenes

Irradiation of 3-(4-substituted styryl)furans in basic media yielded a series of 7-substituted-2-methylnaphthalenes, including methoxy, isopropyl, ethyl, methyl, fluoro, and cyano substituents. This base-induced photorearrangement involves cis-trans photoisomerization, 6e photocyclization, base-induced elimination, and a Norrish Type I photoreaction and is a novel method to synthesize unsymmetrical 2,7-disubstituted naphthalenes.     

Studies on tolonium chloride labeled with radioiodine

Tolonium chloride is a common reagent in the diagnosis of oral premalignant and malignant lesions. This study establishes the optimal preparation of radioiodinated tolonium chloride (RTC) and evaluate its radiochemical and biological characteristics. Instant thin layer chromatography (ITLC), ion exchange chromatography (IC), paper electrophoresis, and the effect of pH on labeling efficiency revealed the chemical characterization of RTC. Biodistribution, blood clearance, urinary excretion, toxic effect, and Lugol’s solution effect on the thyroid uptake of RTC revealed RTCs biological characteristics. The optimal labeling condition was pH = 2.96 after 15 h stirring, the labeling efficiency was 60%. After purification by IC, the radiochemical purity of RTC was 94%, and the shelf life of RTC was at least 90 days. In the biodistribution study, the liver was major target organs, approximated 6.11% of injected dose accumulate in per gram of tissue (6.11% ID/g) at 10 min after injection. The tissue-to-blood radioactivity ratio significant (p < 0.05) increased with reaction time. In liver, the tissue-to-blood radioactivity ratio was 2.2 ± 0.51 at 10 min after injection, and increased to 22.4 ± 4.52 at 120 min after injection. The blood clearance study showed a significant decrease in blood radioactivity. The radioactivity in the blood was about 2.76% of the injected dose per milliliter blood at 10 min post-injection, but decreased to 0.12% at 120 min post-injection. Lugol’s solution does not affect the thyroid uptake of RTC. Almost all the administered RTC recovered at 60 h after injection, with 79% recovered in feces and 17% recovered in urine. This study shows that RTC is non-toxic, and may be suitable as a liver imaging agent.     

Structural Manipulation of Ruthenium(II) Polypyridine Nitrone Complexes to Generate Phosphorogenic Bioorthogonal Reagents for Selective Cellular Labeling

We report a new class of ruthenium(II) polypyridine complexes functionalized with a nitrone group as phosphorogenic bioorthogonal probes. These complexes were very weakly emissive owing to rapid C=N isomerization of the nitrone moiety, but exhibited significant emission enhancement upon strain‐promoted alkyne–nitrone cycloaddition (SPANC) reaction with bicyclo[6.1.0]nonyne (BCN)‐modified substrates. The modification of nitrone with a dicationic ruthenium(II) polypyridine unit at the α‐C‐position and a phenyl ring at the N‐position led to remarkably accelerated reaction kinetics, which are substantially greater (up to ≈278 fold) than those of other acyclic nitrone–BCN systems. Interestingly, the complexes achieved specific cell membrane/cytosol staining upon specific labeling of an exogenous substrate, BCN‐modified decane (BCN‐C10), in live cells. Importantly, the in situ generation of the more lipophilic isoxazoline adduct in the cytoplasm resulted in increased cytotoxicity, highlighting a novel approach to apply the SPANC labeling technique in drug activation.