Proton–deuterium exchange of acetone catalyzed in imidazolium-based ionic liquid–D2O mixtures

The reaction of the proton–deuterium exchange of acetone in imidazolium-based ionic liquid (IL)–deuterium oxide mixtures was studied in detail via NMR spectroscopy. Certain ILs exhibit considerable catalytic properties and contribute to the course of reaction up to the complete deuteration. The efficiency of deuterium exchange crucially depends on the features of ILs; the type of anion and chain length of cation. The linear secondary isotope effects on the NMR chemical shifts of the ¹³C atoms in acetone were observed depending on the deuteration level of the molecule.

The reaction of the proton–deuterium exchange of acetone in imidazolium-based ionic liquid (IL)–deuterium oxide mixtures was studied in detail via NMR spectroscopy.     

Methotrexate and aminopterin exhibit similar in vitro and in vivo preclinical activity against acute lymphoblastic leukaemia and lymphoma

Due to the development of neurological toxicity and resistance to methotrexate (MTX), other antifolates have been evaluated for its potential replacement in the treatment of childhood acute lymphoblastic leukaemia (ALL). Aminopterin (AMT) has been suggested to provide clinical advantages over MTX and other antifolates. AMT activity, compared with MTX, was evaluated in ALL and lymphoma preclinical models. The minimum survival fraction at the range of concentrations tested was lower with AMT than with MTX in 3 out of 15 cell lines. Both AMT and MTX significantly extended the event-free survival of mice bearing 3 out of 4 xenografts with equivalent activity.     

Population genetics of familial Mediterranean fever: a review

In this review, some principal population genetic features of familial Mediterranean fever (FMF) are considered. These relate to the time and the place of founder mutations' origins, the role of ancient migrations and contacts between populations in the spatial spreading of the disorder, the influence of environmental factors and cultural traditions on the rate of FMF incidence, and possible selective advantage in carriers of FMF causing gene (MEFV) mutations.     

Improved clinical outcomes for multiple myeloma patients treated at a single specialty clinic

Despite recent advances made in its treatment, multiple myeloma (MM) remains an incurable B cell malignancy. Thus, the objective for treating these patients is to prolong overall survival (OS) and preserve patients’ quality of life. We have analyzed data from 264 consecutive MM patients who had their initial visit between July 1, 2004 and December 1, 2014 and have received treatment in a single clinic specializing in MM. We determined their progression-free survival (PFS, OS, and 5-year OS). The PFS for frontline (n = 165 treatments), salvage (n = 980), and all treatments (n = 1145) were 13.9, 4.6, and 5.5 months, respectively. The median OS of all patients was 98 months with a 5-year survival of 74%. The results of this study show a marked improvement in OS for unselected MM patients compared with historical data. There were no significant differences in OS between patients with different International Staging System (ISS) stages. Younger patients (<65 years old) showed a longer OS. The results of this study should help physicians predict outcomes for MM patients and be encouraging for patients with this B cell malignancy.     

Synthesis of Dihydrochlorides of Azaadamantanes Containing 8-Hydroxyquinoline Fragments and their Antibacterial Activity in Mice with Dysentery and Staphylococcal Infections

Pharmaceutical Chemistry Journal - New azaadamantane derivatives containing 8-hydroxyquinoline fragments were synthesized. Their antibacterial activity was studied. The synthesized compounds...     

From the Cover: Dislocation theory of chirality-controlled nanotube growth

The periodic makeup of carbon nanotubes suggests that their formation should obey the principles established for crystals. Nevertheless, this important connection remained elusive for decades and no theoretical regularities in the rates and product type distribution have been found. Here we contend that any nanotube can be viewed as having a screw dislocation along the axis. Consequently, its growth rate is shown to be proportional to the Burgers vector of such dislocation and therefore to the chiral angle of the tube. This is corroborated by the ab initio energy calculations, and agrees surprisingly well with diverse experimental measurements, which shows that the revealed kinetic mechanism and the deduced predictions are remarkably robust across the broad base of factual data.     

Ultrasensitive gas detection of large-area boron-doped graphene

Heteroatom doping is an efficient way to modify the chemical and electronic properties of graphene. In particular, boron doping is expected to induce a p-type (boron)-conducting behavior to pristine (nondoped) graphene, which could lead to diverse applications. However, the experimental progress on atomic scale visualization and sensing properties of large-area boron-doped graphene (BG) sheets is still very scarce. This work describes the controlled growth of centimeter size, high-crystallinity BG sheets. Scanning tunneling microscopy and spectroscopy are used to visualize the atomic structure and the local density of states around boron dopants. It is confirmed that BG behaves as a p-type conductor and a unique croissant-like feature is frequently observed within the BG lattice, which is caused by the presence of boron-carbon trimers embedded within the hexagonal lattice. More interestingly, it is demonstrated for the first time that BG exhibits unique sensing capabilities when detecting toxic gases, such as NO₂ and NH₃, being able to detect extremely low concentrations (e.g., parts per trillion, parts per billion). This work envisions that other attractive applications could now be explored based on as-synthesized BG.Graphene is a fascinating material that has created an unprecedented impact in condensed-matter physics, chemistry, materials science, and industry (1–6). According to theory, the valence and conduction bands of pristine (nondoped) graphene (PG) touch at the K point in the Brillouin zone, thus making it behave as a zero-overlap semimetal (7). This lack of band gap limits graphene applications in some areas including semiconductor electronics. Therefore, it is crucial to tailor the electronic properties of graphene and eventually be able to open an electronic band gap. Doping, especially chemical doping, constitutes an efficient way to modify the electronic, chemical, and magnetic properties of materials. Recently, exciting progress has been achieved regarding graphene chemical doping, and more detailed information can be found in the literature (8, 9). Among different dopants, the two most adjacent neighbors of carbon in the periodic table of the elements (i.e., B and N) have attracted the attention of numerous scientists because of their similar atomic sizes with C and potential to induce p-type (boron) and n-type (nitrogen) conduction in graphene. In particular, the synthesis of N-doped graphene (NG) (10–14), as well as its atomic scale characterization (15–18) and possible applications (19–21), have been well explored. However, experimental progress on boron-doped graphene (BG) (22–27) is still very scarce compared with that on NG. Actually, theoretical work on BG has been extensively carried out to demonstrate the properties of BG and its possible applications, including field-effect transistors (FETs) (28), hydrogen storage (29), and Li-ion batteries (LIBs) (30). In particular, density functional theory (DFT) calculations predicted that FETs fabricated with BG could exhibit high ON/OFF ratios and low subthreshold swings (28). Moreover, B atoms embedded within the graphene lattice can lead to improved hydrogen storage capacity by decreasing the H₂ adsorption energy dramatically (29). Compared with PG, more Li ions could be captured around boron-doping sites in BG because of the formation of an electron-deficient structure. In this context, Yakobson et al. have demonstrated that the substitutional doping of boron in graphene could lead to much improved Li storage performance with small volume variation during discharge/charge cycles and a capacity of 857 mAh/g (as Li_1.5C₃B), which is two times higher than that of graphite (372 mAh/g) (30). Besides that, it has been theoretically demonstrated that BG could break the symmetry of spin-up and spin-down transmittance channel, thus leading to a metallic-to-semiconductor transition. In this sense, it is believed that BG could become a good candidate for developing spin filter devices. Moreover, from the theoretical standpoint, it has been recently demonstrated that the sensitivity and selectivity of graphene-based gas sensors could be remarkably enhanced by incorporating dopants or defects within the graphene lattice (31). These results open up the possibility of constructing excellent graphene-based sensors to efficiently detect flammable and toxic gases.To experimentally confirm some of the above-mentioned theoretical predictions, it is important to be able to synthesize large-area, highly crystalline BG in a controllable and reproducible way. Furthermore, it is very important to visualize how B atoms bond to C atoms within the sp² hybridized carbon layer to understand the electronic and chemical properties of BG. The present work describes the controlled growth of large-area (∼cm²), high-crystallinity BG sheets grown on copper foils by bubbler-assisted chemical vapor deposition (BA-CVD) at atmospheric pressure. Scanning tunneling microscopy/spectroscopy (STM/STS) was used to understand the electronic features associated with boron dopants at the atomic scale. Characteristic croissant-like (or boomerang-like) features within the BG samples were observed via STM, which are very different from the single substitutional B-dopants observed in BG samples synthesized by low-pressure CVD (LP-CVD) routes (23). These features can be attributed to a vacancy-substitution complex involving three quasiadjacent B atoms. This was confirmed by comparing the experimental STM and STS data with corresponding simulations using state-of-the-art first-principles calculations. As a proof-of-concept, it is demonstrated, for the first time to our knowledge, that boron doping in graphene could lead to an enhanced sensitivity when detecting toxic gases, such as NO₂ and NH₃. It is foreseen that the large-area BG sheets described here could result in novel electronic or magnetic properties not reported hitherto.