Greigite magnetosome membrane ultrastructure in ‘Candidatus Magnetoglobus multicellularis’

The ultrastructure of the greigite magnetosome membrane in the multicellular magnetotactic bacteria ‘Candidatus Magnetoglobus multicellularis’ was studied. Each cell contains 80 membrane-enclosed iron-sulfide magnetosomes. Cytochemistry methods showed that the magnetosomes are enveloped by a structure whose staining pattern and dimensions are similar to those of the cytoplasmic membrane, indicating that the magnetosome membrane likely originates from the cytoplasmic membrane. Freeze-fracture showed intramembrane particles in the vesicles surrounding each magnetosome. Observations of cell membrane invaginations, the trilaminar membrane structure of immature magnetosomes, and empty vesicles together suggested that greigite magnetosome formation begins by invagination of the cell membrane, as has been proposed for magnetite magnetosomes

The Problem of Large Leptonic Mixing

Unlike in the quark sector where simple $S_3$ permutation symmetries can generate the general features of quark masses and mixings, we find it impossible (under conditions of hierarchy for the charged leptons and without considering the see-saw mechanism or a more elaborate extension of the SM) to guarantee large leptonic mixing angles with any general symmetry or transformation of only known particles. If such symmetries exist, they must be realized in more extended scenarios.Comment: RevTeX, 4 pages, no figure

Synthesis and stereochemical assignment of methyl 3-(3-hydroxyphenoxy) acrylate via cis-trans photoisomerization

Methyl 3-(3-hydroxyphenoxy)acrylate (2), a new and important starting material for several reactions and a potential precursor of the natural product 3-(3-hydroxyphenoxy)-2-propenal (1), was synthesized from resorcinol and methyl propiolate. The trans configuration of the double bond present in 2 was confirmed through a photoisomerization reaction.3-(3-Hidroxi-fenoxi)acrilato de metila (2), um novo e importante material de partida para inúmeras reações e um precursor potencial do produto natural 3-(3-hidroxi-fenoxi)-2-propenal (1), foi sintetizado a partir de resorcinol e propiolato de metila. A configuração trans da dupla ligação presente no composto 2 foi confirmada através de uma reação de fotoisomerização.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Drying of microalga Spirulina platensis in a rotary dryer with inert bed

[EN] The aim of this work is investigate the use of a rotary dryer with inert bed for drying of microalga Spirulina platensis. The influence of air temperature, feed rate, rotation speed and inerts filling degree was quantified. The contents of main bioactive compounds were also analyzed. The results shown that the used drying system proved to be an interesting alternative for a possible use of this microalga, if performed under adequate conditions. It was identified conditions with high drying performance and with the preservation of product qualitySilva, NC.; Silva, TC.; Santos, AO.; Graton, IS.; Duarte, CR.; Barrozo, M. (2018). Drying of microalga Spirulina platensis in a rotary dryer with inert bed. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 1535-1542. https://doi.org/10.4995/IDS2018.2018.7457OCS1535154

A Model of Quark and Lepton Masses I: The Neutrino Sector

If neutrinos have masses, why are they so tiny? Are these masses of the Dirac type or of the Majorana type? We are already familiar with the mechanism of how to obtain a tiny Majorana neutrino mass by the famous see-saw mechanism. The question is: Can one build a model in which a tiny Dirac neutrino mass arises in a more or less "natural" way? What would be the phenomenological consequences of such a scenario, other than just merely reproducing the neutrino mass patterns for the oscillation data? In this article, a systematic and detailed analysis of a model is presented, with, as key components, the introduction of a family symmetry as well as a new SU(2) symmetry for the right-handed neutrinos. In particular, in addition to the calculations of light neutrino Dirac masses, interesting phenomenological implications of the model will be presented.Comment: 25 (single-spaced) pages, 11 figures, corrected some typos in Table I, added acknowledgement

Vector-like Singlet Quarks: a Roadmap

We review the theory and phenomenology of isosinglet vector-like quarks (VLQs). In recent years, interest in VLQs has been increasing, due to their contributions to new physics effects that can be tested in experiments at LHC and High-Luminosity LHC. The similarities of models with isosinglet VLQs and the seesaw framework in the leptonic sector are pointed out. The existence of VLQs leads to flavour-changing neutral currents at tree level and deviations from unitarity of the CKM matrix, introducing rich phenomenological implications. These new effects are naturally suppressed by the masses of the new quarks, that are constrained to be above the electroweak scale. In addition, striking new effects can be achieved with the inclusion of an extra complex scalar singlet. Such a minimal extension of the SM can give rise to new sources of CP violation with profound theoretical implications, allowing for a solution to the strong CP problem and a possible explanation for the baryon asymmetry of the Universe. We list and explain strong motivations to consider this class of models. We also briefly review how models with VLQs can be matched to the SM effective field theory (SMEFT). A detailed analysis of flavour observables that can be affected by the presence of VLQs is presented. Current bounds from collider searches of VLQs are summarized. We point out that the discovery of VLQs can be within the reach of present or future colliders being planned.Comment: 109 pages, 7 figures, 7 tables. Work intended as a review. Comments, suggestions and missing references are welcome

Well-posedness of minimal time problems with constant dynamics in Banach spaces

This paper concerns the study of a general minimal time problem with a convex constant dynamics and a closed target set in Banach spaces. We pay the main attention to deriving sufficient conditions for the major well-posedness properties that include the existence and uniqueness of optimal solutions as well as certain regularity of the optimal value function with respect to state variables. Most of the results obtained are new even in finite-dimensional spaces. Our approach is based on advanced tools of variational analysis and generalized differentiation

Biochars from animal wastes as alternative materials to treat colored effluents containing Basic Red 9

Bovine bones (BB) and fish scales (FS) were used as alternative precursors to produce biochars, which in turn, were applied for the removal of Basic Red 9 (BR9) from aqueous solutions. BB and FS were pyrolyzed generating a solid (biochars), a liquid (pyrolytic oils) and a gas fraction. All fractions were characterized to evaluate the pyrolysis process. The biochars presented different functional groups and a mesoporous structure with surface areas around 90 m2 g–1. Both biochars demonstrated potential to adsorb BR9, with maximum adsorption capacities of 49.5 (BB–biochar) and 52.3 mg g–1 (FS–biochar). Pyrolytic oils were composed mainly by palmitic acid (BB) and imidazolidinedione (FS), which are compounds with biological and antioxidant activity. Pyrolysis of BB generated CO2 while pyrolysis of FS generated H2. In summary, bovine bones and fish scales are promising precursors to concomitantly produce biochars with great adsorbent potential and oils with interesting characteristics

Large Neutrino Mixing with Universal Strength of Yukawa Couplings

We analyse, within the framework of universal strength for Yukawa couplings (USY), various structures for the Dirac and Majorana neutrino mass matrices giving rise, through the see-saw mechanism, to a degenerate mass spectrum. A specific USY ansatz is presented for the charged lepton and neutrino effective mass matrix, leading to quasi-degenerate neutrinos and a leptonic mixing matrix which provides a large angle solution for both the atmospheric and solar neutrino problems.Comment: 7 pages, ReVTeX, small comments adde

Association between ventilation index and time on mechanical ventilation in infants with acute viral bronchiolitis

OBJECTIVE: To evaluate the association between time on mechanical ventilation and anthropometric, clinical and pulmonary function variables, measured early, in infants on invasive mechanical ventilation with acute respiratory failure due to viral bronchiolitis, and the temporal progression of variables with significant correlations. METHODS: Twenty-nine infants admitted to the pediatric intensive care unit of UNICAMP university hospital were studied. Acute viral bronchiolitis was defined according to clinical and radiological criteria. Children with chronic diseases and those that were hemodynamically unstable were excluded. All measurements were taken after 24 to 72 hours' mechanical ventilation, using volumetric capnography and blood gas analysis. Mechanical ventilation time was divided into: 7 days. Association between time on mechanical ventilation and the variables analyzed was determined by Spearman's Correlation Coefficient (r s). RESULTS: Time on mechanical ventilation showed a significant positive correlation with PaCO2 (r s = 0.45, p = 0.01) and ventilation index (r s = 0.51, p = 0.005), and a negative correlation with pH (r s = -0.40, p = 0.03). Ventilation indices of 37, measured between day one and day five, was associated with a progressively increased risk of more than 7 days on mechanical ventilation (OR = 4.2 on the first day to 15.71 on the fourth day). CONCLUSION: Ventilation index, PaCO2 and pH, measured early, were associated with prolonged mechanical ventilation, reflecting the severity of ventilatory disturbance and the need for support.OBJETIVO: Avaliar a associação entre tempo de ventilação mecânica e variáveis antropométricas, clínicas e de função pulmonar, precocemente, em lactentes com insuficiência respiratória por bronquiolite viral aguda em ventilação mecânica invasiva, e a evolução temporal das variáveis significativamente correlacionadas. MÉTODOS: Foram estudados 29 lactentes admitidos na unidade de terapia intensiva pediátrica do Hospital de Clínicas da UNICAMP, com diagnóstico de bronquiolite viral aguda, definido por critérios clínicos e radiológicos. Lactentes com doenças crônicas ou instabilidade hemodinâmica foram excluídos. Todas as medidas foram feitas entre 24 e 72 horas em ventilação mecânica, usando capnografia volumétrica e análise dos gases sangüíneos. O tempo de ventilação mecânica foi dividido em: menor ou igual que 7 dias e maior que 7 dias. A associação entre o tempo de ventilação e as variáveis analisadas foi determinada pelo coeficiente de correlação de Spearman (r s) RESULTADOS: O tempo de ventilação mecânica apresentou correlação positiva significativa com a PaCO2 (r s = 0,45, p = 0,01) e com o índice de ventilação (r s = 0,51, p = 0,005), e negativa com o pH (r s = -0,40, p = 0,03). Índice de ventilação com valor de 37, avaliado do primeiro ao quinto dia, foi associado a risco progressivamente aumentado de tempo de ventilação mecânica maior que 7 dias (OR = 4,2 no primeiro dia a 15,71 no quarto dia) CONCLUSÕES: Índice ventilatório, PaCO2 e pH, precocemente medidos, foram associados com tempo prolongado em ventilação mecânica, refletindo a gravidade do distúrbio ventilatório e necessidade de suporte.46647