Inelastic light scattering and the excited states of many-electron quantum dots

A consistent calculation of resonant inelastic (Raman) scattering amplitudes for relatively large quantum dots, which takes account of valence-band mixing, discrete character of the spectrum in intermediate and final states, and interference effects, is presented. Raman peaks in charge and spin channels are compared with multipole strengths and with the density of energy levels in final states. A qualitative comparison with the available experimental results is given.Comment: 5 pages, accepted in J. Phys.: Condens. Matte

Mesenchymal stem cells and their use as cell replacement therapy and disease modelling tool.

Mesenchymal stem cells (MSCs) from adult somatic tissues may differentiate in vitro and in vivo into multiple mesodermal tissues including bone, cartilage, adipose tissue, tendon, ligament or even muscle. MSCs preferentially home to damaged tissues where they exert their therapeutic potential. A striking feature of the MSCs is their low inherent immunogenicity as they induce little, if any, proliferation of allogeneic lymphocytes and antigen-presenting cells. Instead, MSCs appear to be immunosuppressive in vitro. Their multilineage differentiation potential coupled to their immuno-privileged properties is being exploited worldwide for both autologous and allogeneic cell replacement strategies. Here, we introduce the readers to the biology of MSCs and the mechanisms underlying immune tolerance. We then outline potential cell replacement strategies and clinical applications based on the MSCs immunological properties. Ongoing clinical trials for graft-versus-host-disease, haematopoietic recovery after co-transplantation of MSCs along with haematopoietic stem cells and tissue repair are discussed. Finally, we review the emerging area based on the use of MSCs as a target cell subset for either spontaneous or induced neoplastic transformation and, for modelling non-haematological mesenchymal cancers such as sarcomas

Nonlinear Breathing-like Localized Modes in C60 Nanocrystals

We study the dynamics of nanocrystals composed of C60 fullerene molecules. We demonstrate that such structures can support long-lived strongly localized nonlinear oscillatory modes, which resemble discrete breathers in simple lattices. We reveal that at room temperatures the lifetime of such nonlinear localized modes may exceed tens of picoseconds; this suggests that C60 nanoclusters should demonstrate anomalously slow thermal relaxation when the temperature gradient decays in accord to a power law, thus violating the Cattaneo-Vernotte law of thermal conductivity.Comment: 6 pages, 6 figure

Genomic characteristics and comparative genomics analyses of non-rhizobial endophytic bacteria isolated from legumes.

In addition to typical nitrogen-fixing endosymbionts, legumes harbour other endophytic bacteria within their tissues that may also contribute to plant growth and health (Hardoim et al. 2015). Our previous works revealed that endophytic bacteria isolated from legumes not only have plant growth-promoting traits but are also well adapted to common constraints present in soils of the Mediterranean region (Brígido et al. 2019ab). In this work, we intend to further characterize these endophytic bacteria through genomic and comparative genomic analyses to potentiate their applications in agriculture, providing opportunities for sustainable plant health and food security. Twelve endophytic bacterial isolates were selected based on their potential for plant growth promotion and/or biocontrol of phytopathogens. Based on the 16S rRNA gene sequence analysis, the isolates were assigned to the genera Pseudomonas, Kosakonia, Stenotrophomonas, Serratia, Bacillus and Agrobacterium. Nevertheless, in silico DNA-DNA hybridization analyses revealed that 3 strains represent novel species distinct from their closest relatives. Their genome sizes ranged from 4.4 M to 7.1 M with a GC content varying from 35.41 to 66.4%. Orthologous gene clusters analysis revealed 9346 clusters and 345 single-copy gene clusters, albeit only 499 gene clusters (comprising 6110 proteins) were shared among all strains. Whole genome sequence analysis revealed genes potentially associated with attachment and plant colonization, growth promotion and stress protection as well as antifungal activity. In detail, sets of genes for twitching motility, chemotaxis, flagella biosynthesis, and ability to form biofilms (which are related with host plant colonization) were found in their genomes. Presence of genes associated to nitrogen fixation, auxin biosynthesis, siderophore production or phosphorous assimilation reveals their potential as plant growth promoters. Furthermore, genes required for biosynthesis of pyoluteorin, 2,4-diacetylphloroglucinol and pyrrolnitrin underline bacterial biocontrol potential against phytopathogens. Genes related to the production of different molecules and enzymes mediating stress tolerance suggest their ability to rapidly adapt to stressful conditions. Overall, our data provide a better understanding of these endophytic bacteria abilities and further comparative genomic analysis provided insight into the genomic basis of their endophytic lifestyle, plant growth promotion and antifungal activity

Varying efficacy of intermittent preventive treatment for malaria in infants in two similar trials: public health implications.

BACKGROUND\ud \ud Intermittent preventive treatment (IPTi) with sulphadoxine-pyrimethamine (SP) in infants resulted in different estimates of clinical malaria protection in two trials that used the same protocol in Ifakara, Tanzania, and Manhiça, Mozambique. Understanding the reasons for the discrepant results will help to elucidate the action mechanism of this intervention, which is essential for rational policy formulation.\ud \ud METHODS\ud \ud A comparative analysis of two IPTi trials that used the same study design, follow-up, intervention, procedures and assessment of outcomes, in Tanzania and Mozambique was undertaken. Children were randomised to receive either SP or placebo administered 3 times alongside routine vaccinations delivered through the Expanded Program on Immunisation (EPI). Characteristics of the two areas and efficacy on clinical malaria after each dose were compared.\ud \ud RESULTS\ud \ud The most relevant difference was in ITN's use ; 68% in Ifakara and zero in Manhiça. In Ifakara, IPTi was associated with a 53% (95% CI 14.0; 74.1) reduction in the risk of clinical malaria between the second and the third dose; during the same period there was no significant effect in Manhiça. Similarly, protection against malaria episodes was maintained in Ifakara during 6 months after dose 3, but no effect of IPTi was observed in Manhiça.\ud \ud CONCLUSION\ud \ud The high ITN coverage in Ifakara is the most likely explanation for the difference in IPTi efficacy on clinical malaria. Combination of IPTi and ITNs may be the most cost-effective tool for malaria control currently available, and needs to be explored in current and future studies.\ud \ud TRIAL REGISTRATION\ud \ud Manhiça study registration number: NCT00209795Ifakara study registration number: NCT88523834

Design, construction and evaluation of a 3D printed electrochemical flow cell for the synthesis of magnetite nanoparticles

A 3D-printed prototype of an electrochemical flow cell for the synthesis of superparamagnetic magnetite nanoparticles of medium size between 15 and 30 nm was constructed and its performance was evaluated. The cell consists of a series of rectangular channels in a parallel electrode arrangement. Electrolyte flows through the channels as the electric current is supplied to the system and a combination of electrochemical and chemical reactions create the appropriate conditions for magnetite precipitation. Different electric configurations were evaluated and both energy and production efficiencies were calculated to determine the best configuration. Different flow and current values were also investigated, and all the materials were analyzed by X-ray diffraction, transmission electron microscopy, Mossbauer spectroscopy and magnetization curve measurements to determine their effect on particle morphology, composition and magnetic behavior. The best results were obtained for a parallel monopolar configuration, with 100 mA (3 mA cm−2) passing in each two electrodes and a flow value of 30 mL min−1, yielding an energy efficiency of 5.9 kJ g−1 and a production rate of 12.1 mg min−1, approximately 6 times higher than the 100 mL standard cell previously used. Magnetic saturation was 77.3 emu g−1, slightly lower than the bulk material (92–100 emu g−1)The authors gratefully acknowledge the scholarship for doctoral studies of Gerardo Ivan Lozano Gutierrez granted by the National Council of Science and Technology of Mexico (CONACyT). The authors are also grateful to the Ministry of Economy and Competitiveness for the project MAT2015-67557-C2-2-P. Support for a sabbatical leave for NCS from the National Council of Science and Technology of Mexico and Exportadora de Postes S.A. de C.V. are greatly appreciate

Phonon-assisted optical absorption in germanium

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Determining the nuclear neutron distribution from Coherent Elastic neutrino-Nucleus Scattering: current results and future prospects

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS), a process recently measured for the first time at ORNL's Spallation Neutron Source, is directly sensitive to the weak form factor of the nucleus. The European Spallation Source (ESS), presently under construction, will generate the most intense pulsed neutrino flux suitable for the detection of CE$\nu$NS. In this paper we quantify its potential to determine the root mean square radius of the point-neutron distribution, for a variety of target nuclei and a suite of detectors. To put our results in context we also derive, for the first time, a constraint on this parameter from the analysis of the energy and timing data of the CsI detector at the COHERENT experiment.Comment: 16 pages, 4 figures. Minor text changes and references added. Matches version accepted by JHE