Among the human copper-containing monooxygenases, Tyrosinase (Ty) is an important enzyme involved in the determinant step of the biosynthetic pathway of melanin pigment. In this pathway, Ty catalyzes the tyrosine monooxygenation into L-DOPA-quinone, which is the precursor of the skin pigment melanin. Ty inhibitors/activators are a well-established approach for controlling in vivo melanin production, so their development has a huge economical and industrial impact. Moreover, recent publications highlight that targeting tyrosinase with inhibitors/activators to treat melanogenesis disorders is one of many possible approaches, due to the complex biochemical reaction involved in the melanin synthesis.

With the aim to develop effective and selective human tyrosinase inhibitors, we investigated aurone derivatives whose B-ring was replaced by a non-oxidizable 2-hydroxypyridine-N-oxide (HOPNO) moiety. These aurones were synthesized and evaluated as inhibitors of purified human tyrosinase. Excellent inhibition activity was revealed and rationalized by theoretical calculations. The aurone backbone was especially found to play a crucial role, as the HOPNO moiety alone provided very modest activity on human tyrosinase. Furthermore, the in vitro activity was confirmed by measuring the melanogenesis suppression ability of the compounds in melanoma cell lysates and whole cells. Our study reveals that HOPNO-embedded 6-hydroxyaurone is to date the most effective inhibitor of isolated human tyrosinase. Owing to its low toxicity and its high inhibition activity, it could represent a milestone on the path toward new valuable agents in dermocosmetics, as well as in medical fields where it was recently suggested that tyrosinase could play key roles.

Field-effect transistors (FETs) form an established technology for sensing applications. However, recent advancements and use of high-performance multigate metal-oxide semiconductor FETs (double-gate, FinFET, trigate, gate-all-around) in computing technology, instead of bulk MOSFETs, raise new opportunities and questions about the most suitable device architectures for sensing integrated circuits. In this work, we propose pH and ion sensors exploiting FinFETs fabricated on bulk silicon by a fully CMOS compatible approach, as an alternative to the widely investigated silicon nanowires on silicon-on-insulator substrates. We also provide an analytical insight of the concept of sensitivity for the electronic integration of sensors. N-channel fully depleted FinFETs with critical dimensions on the order of 20 nm and HfO2 as a high-k gate insulator have been developed and characterized, showing excellent electrical properties, subthreshold swing, SS ∼ 70 mV/dec, and on-to-off current ratio, Ion/Ioff ∼ 10(6), at room temperature. The same FinFET architecture is validated as a highly sensitive, stable, and reproducible pH sensor. An intrinsic sensitivity close to the Nernst limit, S = 57 mV/pH, is achieved. The pH response in terms of output current reaches Sout = 60%. Long-term measurements have been performed over 4.5 days with a resulting drift in time δVth/δt = 0.10 mV/h. Finally, we show the capability to reproduce experimental data with an extended three-dimensional commercial finite element analysis simulator, in both dry and wet environments, which is useful for future advanced sensor design and optimization.

The combination of N-Boc-protected alpha-amino acid hydroxyamides (pseudo-dipeptides) and [{Ru(p-cymene)Cl(2)}(2)] resulted in the formation of superior catalysts for the asymmetric transfer hydrogenation (ATH) of non-activated aryl alkyl ketones in propan-2-ol. The overall kinetics of the ATH of acetophenone to form 1-phenylethanol in the presence of ruthenium pseudo-dipeptide catalysts were studied, and the individual rate constants for the processes were determined. Addition of lithium chloride to the reaction mixtures had a strong influence on the rates and selectivities of the processes. Kinetic isotope effects (KIEs) for the reduction were determined and the results clearly show that the hydride transfer is rate-determining, whereas no KIEs were detected for the proton transfer. From these observations a novel bimetallic outer-sphere-type mechanism for these ATH process is proposed, in which the bifunctional catalysts mediate the transfer of a hydride and an alkali metal ion between the hydrogen donor and the substrate. Furthermore, the use of a mixture of propan-2-ol and THF (1:1) proved to enhance the rates of the ATH reactions. A series of aryl alkyl ketones were reduced under these conditions in the presence of 0.5 mol % of catalyst, and the corresponding secondary alcohols were formed in high yields and with excellent enantioselectivities (>99% ee) in short reaction times.

Pure thin films of organotin compounds have been lithographically evaluated using extreme ultraviolet lithography (EUVL, 13.5 nm). Twenty compounds of the type R 2 SnðO 2 CR 0 Þ 2 were spin-coated from solutions in toluene, exposed to EUV light, and developed in organic solvents. Exposures produced negative-tone contrast curves and dense-line patterns using interference lithography. Contrast-curve studies indicated that the photosensitivity is linearly related to the molecular weight of the carboxylate group bound to tin. Additionally, photosensitivity was found to be linearly related to free radical stability of the hydrocarbon group bound directly to tin (R ¼ phenyl, butyl, and benzyl). Dense-line patterning capabilities varied, but two resists in particular show exceptionally good line edge roughness (LER). A resist composed of an amorphous film of ðC 6 H 5 CH 2 Þ 2 SnðO 2 CCðCH 3 Þ 3 Þ 2 (1) achieved 1.4 nm LER at 22-nm half-pitch patterning and a resist composed of ðC 6 H 5 CH 2 Þ 2 SnðO 2 CC 6 H 5 Þ 2 (2) achieved 1.1 nm LER at 35-nm half-pitch at high exposure doses (600 mJ∕cm 2 ). Two photoresists that use olefin-based carboxylates, ðC 6 H 5 CH 2 Þ 2 SnðO 2 CCH═CH 2 Þ 2 (3) and ðC 6 H 5 CH 2 Þ 2 SnðO 2 CCðCH 3 Þ═CH 2 Þ 2 (4), demonstrated better photospeeds (5 mJ∕cm 2 and 27 mJ∕cm 2 ) but worse LER.

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Tertiary amides were efficiently reduced to their corresponding tertiary amines in high isolated yields by using the commercially available and inexpensive polymeric silane polymethylhydrosiloxane (PMHS) as the reducing agent. The reaction is efficiently catalyzed by an in situ generated iron/N‐heterocyclic carbene complex (1 mol‐%) obtained from iron(II) acetate and 1‐(2‐hydroxy‐2‐phenylethyl)‐3‐methylimidazolium triflate ([PhHEMIM][OTF]). A catalytic amount of lithium chloride (1 mol‐%) present in the reaction mixture significantly reduced the reaction time and increased the chemoselectivity of the reduction process.

Aromatic aldehydes, along with aryl alkyl, heteroaryl alkyl, and dialkyl ketones were efficiently reduced to their corresponding primary and secondary alcohols, respectively, in high yields, using the commercially available and inexpensive polymeric silane, polymethylhydrosiloxane (PMHS), as reducing agent. The reaction is catalyzed by in situ generated iron complexes containing hydroxyethyl-functionalized NHC ligands. Turnover frequencies up to 600 h À1 were obtained.