Iron‐Mediated Electrophilic Amination of Organozinc Halides using Organic Azides

A wide range of alkyl‐, aryl‐ and heteroarylzinc halides were aminated with highly functionalized alkyl, aryl, and heterocyclic azides. The reaction proceeds smoothly at 50 °C within 1 h in the presence of FeCl3 (0.5 equiv) to furnish the corresponding secondary amines in good yields. This method was extended to peptidic azides and provided the arylated substrates with full retention of configuration. To demonstrate the utility of this reaction, we prepared two amine derivatives of pharmaceutical relevance using this iron‐mediated electrophilic amination as the key step

The Brave study: promoting active breaks in secondary school from students’ point of view

Background: According to the WHO recommendations, children and adolescents should perform at least 60 minutes per day of moderate to vigorous physical activity (PA). Active Breaks (ABs) interventions, short physical activity breaks of 5- 15 minutes during school hours, have been examined in primary school children as a potential strategy to counteract a sedentary lifestyle, with minimal disruption to school learning activities. The aim of the BRAVE STUDY is to investigate the feasibility of ABs in a secondary school setting from the students’ point of view. Methods: In December 2020, 10 students (age 12-13, 6 females and 4 males) attending the second and third grade of secondary schools located in Bologna province (Italy) were involved in a focus group (FG). The FG was conducted online because of COVID-19 and the answers transcribed for a later analysis. Students’ opinions were probed on the role of PA in school and possible facilitators/barriers to implementation of ABs in the school. Results: Students reported they wanted to be more active as a consequence of time spent in class sitting at a desk. Students also reported that an organized activity like ABs conducted in the classroom setting provides an excellent opportunity to improve social relations with classmates. Students also highlighted the possible psycho-physical well-being benefits arising from PA. Among the potentially negative aspects reported, students underlined the possible confusion that would be created in classroom and the time subtracted from academic learning activities. Conclusions: The FG represents an ideal mean to obtain in-depth information on how people feel about a pending program or a change in their routine. The current FG reinforces positive outcomes from exposure to a PA program that can be intertwined with their daily classroom activities. ABs programs can help to reconcile the needs of students that arise during the day with the PA objectives recommended by the WHO. Key messages: ABs can be a zero-cost intervention strategy to achieve WHO recommendations and would create conditions for a greater psycho-physical benefits in classrooms. A qualitative approach, such as FGs, provides a mean to collect information not obtainable with quantitative methods, that could be useful to co-design interventions for children and adolescents

A combined microRNA-based targeted therapeutic approach to eradicate glioblastoma stem-like cells

A minor population of glioblastoma stem-like cells (GSCs) has been implicated in the relapse and resistance of glioblastoma to therapeutic treatments. Based on knowledge of the involvement of multiple microRNAs in GSC propagation, we designed a combinational approach to target the GSC population with multiple miRNA-based therapeutics. As carriers for the targeted delivery we took advantage of two aptamers that bind to, and inhibit, the receptor tyrosine kinases, Axl and PDGFRβ. We showed that the aptamer conjugates are transported through an in vitro blood-brain barrier (BBB) model. Furthermore, combining miR-137 and antimiR-10b synergizes with the receptor inhibitory function of aptamer carriers and prevents GSC expansion. Results highlighted the potential of combining multifunctional RNA-based therapeutics for selective targeting of GSCs and offer a proof of principle strategy to potentially fulfill the still unmet need for effective and safe treatment of glioma

Orbifolding the Twistor String

The D-instanton expansion of the topological B-model on the supermanifold CP(3|4) reproduces the perturbative expansion of N=4 Super Yang-Mills theory. In this paper we consider orbifolds in the fermionic directions of CP(3|4). This operation breaks the SU(4) R-symmetry group, reducing the amount of supersymmetry of the gauge theory. As specific examples we take N=1 and N=2 orbifolds and obtain the corresponding superconformal quiver theories. We discuss the D1 instanton expansion in this context and explicitly compute some amplitudes.Comment: 24 pages, 8 figures; v2: minor correction

The evolution of the Compton thick fraction and the nature of obscuration for AGN in the Chandra Deep Field South

(Abridged) We present the results from the X-ray spectral analysis of high-z AGN in the CDFS, making use of the new 4Ms data set and new X-ray spectral models from Brightman & Nandra, which account for Compton scattering and the geometry of the circumnuclear material. Our goals are to ascertain to what extent the torus paradigm of local AGN is applicable at earlier epochs and to evaluate the evolution of the Compton thick fraction (f_CT) with z, important for XRB synthesis models and understanding the accretion history of the universe. In addition to the torus models, we measure the fraction of scattered nuclear light, f_scatt known to be dependant on covering factor of the circumnuclear materal, and use this to aid in our understanding of its geometry. We find that the covering factor of the circumnuclear material is correlated with NH, and as such the most heavily obscured AGN are in fact also the most geometrically buried. We come to these conclusions from the result that f_scatt decreases as NH increases and from the prevalence of the torus model with the smallest opening angle as best fit model in the fits to the most obscured AGN. We find that a significant fraction of sources (~ 20%) in the CDFS are likely to be buried in material with close to 4 pi coverage having been best fit by the torus model with a 0\degree opening angle. Furthermore, we find 41 CTAGN in the CDFS using the new torus models, 29 of which we report here for the first time. We bin our sample by z in order to investigate the evolution of f_CT. Once we have accounted for biases and incompleteness we find a significant increase in the intrinsic f_CT, normalised to LX= 10^43.5 erg/s, from \approx 20% in the local universe to \approx 40% at z=1-4.Comment: Accepted for publication in MNRA

Spectroscopy of new brown dwarf members of rho Ophiuchi and an updated initial mass function

To investigate the universality hypothesis of the initial mass function in the substellar regime, the population of the rho Ophiuchi molecular cloud is analysed by including a new sample of low-mass spectroscopically confirmed members. To that end, we have conducted a large spectroscopic follow-up of young substellar candidates uncovered in our previous photometric survey. The spectral types and extinction were derived for a newly found population of substellar objects, and its masses estimated by comparison to evolutionary models. A thoroughly literature search was conducted to provide an up-to-date census of the cluster, which was then used to derive the luminosity and mass functions, as well as the ratio of brown dwarfs to stars in the cluster. These results were then compared to other young clusters. It is shown that the study of the substellar population of the rho Ophiuchi molecular cloud is hampered only by the high extinction in the cluster ruling out an apparent paucity of brown dwarfs. The discovery of 16 new members of rho Ophiuchi, 13 of them in the substellar regime, reveals the low-mass end of its population and shows the success of our photometric candidate selection with the WIRCam survey. The study of the brown dwarf population of the cluster reveals a high disk fraction of 76 (+5-8)%. Taking the characteristic peak mass of the derived mass function and the ratio of brown dwarfs to stars into account, we conclude that the mass function of rho Ophiuchi is similar to other nearby young clusters.Comment: Accepted to A&A (30 December 2011); v2 includes language editin

Dust tori in radio galaxies

We investigate the validity of the quasar - radio galaxy unification scenario and detect dust tori within radio galaxies of various types. Using VISIR on the VLT, we acquired sub-arcsecond (~0.40") resolution N-band images, at a wavelength of 11.85 micron, of the nuclei of a sample of 27 radio galaxies of four types in the redshift range z=0.006-0.156. The sample consists of 8 edge-darkened, low-power Fanaroff-Riley class I (FR-I) radio galaxies, 6 edge-brightened, class II (FR-II) radio galaxies displaying low-excitation optical emission, 7 FR-IIs displaying high-excitation optical emission, and 6 FR-II broad emission line radio galaxies. Out of the sample of 27 objects, 10 nuclei are detected and several have constraining non-detections at sensitivities of 7 mJy, the limiting flux a point source has when detected with a signal-to-noise ratio of 10 in one hour of source integration. On the basis of the core spectral energy distributions of this sample we find clear indications that many FR-I and several low-excitation FR-II radio galaxies do not contain warm dust tori. At least 57+-19 percent of the high-excitation FR-IIs and almost all broad line radio galaxies display excess infrared emission, which must be attributed to warm dust reradiating accretion activity. The FR-I and low-excitation FR-II galaxies all possess low efficiencies, calculated as the ratio of bolometric and Eddington luminosity log (L_bol/L_Edd) < -3. This suggests that thick tori are absent at low accretion rates and/or low efficiencies. We argue that the unification viewing angle range 0-45 degrees of quasars should be increased to ~60 degrees, at least at lower luminosities.Comment: 17 pages, 9 figures, published in Astronomy and Astrophysics. Version 2 matches published version

Aspergillus ustus Infections among Transplant Recipients

This is the first report of clustered Aspergillus ustus causing systemic disease in transplant patients