Hyperhoneycomb Iridate β-li_{2}iro_{3} As A Platform For Kitaev Magnetism.

A complex iridium oxide β-Li_{2}IrO_{3} crystallizes in a hyperhoneycomb structure, a three-dimensional analogue of honeycomb lattice, and is found to be a spin-orbital Mott insulator with J_{eff}=1/2 moment. Ir ions are connected to the three neighboring Ir ions via Ir-O_{2}-Ir bonding planes, which very likely gives rise to bond-dependent ferromagnetic interactions between the J_{eff}=1/2 moments, an essential ingredient of Kitaev model with a spin liquid ground state. Dominant ferromagnetic interaction between J_{eff}=1/2 moments is indeed confirmed by the temperature dependence of magnetic susceptibility χ(T) which shows a positive Curie-Weiss temperature θ_{CW}∼+40  K. A magnetic ordering with a very small entropy change, likely associated with a noncollinear arrangement of J_{eff}=1/2 moments, is observed at T_{c}=38  K. With the application of magnetic field to the ordered state, a large moment of more than 0.35  μ_{B}/Ir is induced above 3 T, a substantially polarized J_{eff}=1/2 state. We argue that the close proximity to ferromagnetism and the presence of large fluctuations evidence that the ground state of hyperhoneycomb β-Li_{2}IrO_{3} is located in close proximity of a Kitaev spin liquid.

New Interaction Partners For Nek4.1 And Nek4.2 Isoforms: From The Dna Damage Response To Rna Splicing.

Neks are serine-threonine kinases that are similar to NIMA, a protein found in Aspergillus nidulans which is essential for cell division. In humans there are eleven Neks which are involved in different biological functions besides the cell cycle control. Nek4 is one of the largest members of the Nek family and has been related to the primary cilia formation and in DNA damage response. However, its substrates and interaction partners are still unknown. In an attempt to better understand the role of Nek4, we performed an interactomics study to find new biological processes in which Nek4 is involved. We also described a novel Nek4 isoform which lacks a region of 46 amino acids derived from an insertion of an Alu sequence and showed the interactomics profile of these two Nek4 proteins. Isoform 1 and isoform 2 of Nek4 were expressed in human cells and after an immunoprecipitation followed by mass spectrometry, 474 interacting proteins were identified for isoform 1 and 149 for isoform 2 of Nek4. About 68% of isoform 2 potential interactors (102 proteins) are common between the two Nek4 isoforms. Our results reinforce Nek4 involvement in the DNA damage response, cilia maintenance and microtubule stabilization, and raise the possibility of new functional contexts, including apoptosis signaling, stress response, translation, protein quality control and, most intriguingly, RNA splicing. We show for the first time an unexpected difference between both Nek4 isoforms in RNA splicing control. Among the interacting partners, we found important proteins such as ANT3, Whirlin, PCNA, 14-3-3ε, SRSF1, SRSF2, SRPK1 and hNRNPs proteins. This study provides new insights into Nek4 functions, identifying new interaction partners and further suggests an interesting difference between isoform 1 and isoform 2 of this kinase. Nek4 isoform 1 may have similar roles compared to other Neks and these roles are not all preserved in isoform 2. Besides, in some processes, both isoforms showed opposite effects, indicating a possible fine controlled regulation.

(-)-tarchonanthuslactone Exerts A Blood Glucose-increasing Effect In Experimental Type 2 Diabetes Mellitus.

A number of studies have proposed an anti-diabetic effect for tarchonanthuslactone based on its structural similarity with caffeic acid, a compound known for its blood glucose-reducing properties. However, the actual effect of tarchonanthuslactone on blood glucose level has never been tested. Here, we report that, in opposition to the common sense, tarchonanthuslactone has a glucose-increasing effect in a mouse model of obesity and type 2 diabetes mellitus. The effect is acute and non-cumulative and is present only in diabetic mice. In lean, glucose-tolerant mice, despite a slight increase in blood glucose levels, the effect was not significant.

The Conformational Analysis Of 2-halocyclooctanones.

The establishment of the most stable structures of eight membered rings is a challenging task to the field of conformational analysis. In this work, a series of 2-halocyclooctanones were synthesized (including fluorine, chlorine, bromine and iodine derivatives) and submitted to conformational studies using a combination of theoretical calculation and infrared spectroscopy. For each compound, four conformations were identified as the most important ones. These conformations are derived from the chair-boat conformation of cyclooctanone. The pseudo-equatorial (with respect to the halogen) conformer is preferred in vacuum and in low polarity solvents for chlorine, bromine and iodine derivatives. For 2-fluorocyclooctanone, the preferred conformation in vacuum is pseudo-axial. In acetonitrile, the pseudo-axial conformer becomes the most stable for the chlorine derivative. According to NBO calculations, the conformational preference is not dictated by electron delocalization, but by classical electrostatic repulsions.

Distal 22q11.2 Microduplication Combined With Typical 22q11.2 Proximal Deletion: A Case Report.

The 22q11 chromosomal region contains low copy repeats (LCRs) sequences that mediate non-allelic homologous recombination, which predisposes to copy number variations (CNVs) at this locus. Hemizygous deletions of the proximal 22q11.2 region result in the 22q11.2 deletion syndrome (22q11.2 DS). In addition, 22q11.2 duplications involving the distal LCR22s have been reported. This article describes a patient presenting a 2.5-Mb de novo deletion at proximal 22q11.21 region (between LCRs A-D), combined with a 1.3-Mb maternally inherited duplication at distal 22q11.23 region (between LCRs F-H). The presence of concomitant chromosomal imbalances found in this patient has not been reported previously. Clinical and molecular data were compared with literature, in order to contribute to genotype-phenotype correlation. These findings exemplify the complexity and genetic heterogeneity observed in 22q11.2 deletion syndrome and highlights the difficulty to make genetic counseling and predict phenotypic consequences in these situations.

Obesity And Asthma: Beyond T(h)2 Inflammation.

Obesity is a major risk factor for asthma. Likewise, obesity is known to increase disease severity in asthmatic subjects and also to impair the efficacy of first-line treatment medications for asthma, worsening asthma control in obese patients. This concept is in agreement with the current understanding that some asthma phenotypes are not accompanied by detectable inflammation, and may not be ameliorated by classical anti-inflammatory therapy. There are growing evidences suggesting that the obesity-related asthma phenotype does not necessarily involve the classical T(H)2-dependent inflammatory process. Hormones involved in glucose homeostasis and in the pathogeneses of obesity likely directly or indirectly link obesity and asthma through inflammatory and non-inflammatory pathways. Furthermore, the endocrine regulation of the airway-related pre-ganglionic nerves likely contributes to airway hyperreactivity (AHR) in obese states. In this review, we focused our efforts on understanding the mechanism underlying obesity-related asthma by exploring the T(H)2-independent mechanisms leading to this disease.

Contribution of skin immunohistochemistry in the evaluation of nerve fibers in diabetes mellitus type 2

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Polímeros biomiméticos em química analítica. Parte 2: aplicações de MIP (Molecularly Imprinted Polymers) no desenvolvimento de sensores químicos

The aim of this paper is the description of the strategies and advances in the use of MIP in the development of chemical sensors. MIP has been considered an emerging technology, which allows the synthesis of materials that can mimic some highly specific natural receptors such as antibodies and enzymes. In recent years a great number of publications have demonstrated a growth in their use as sensing phases in the construction of sensors . Thus, the MIP technology became very attractive as a promising analytical tool for the development of sensors.

Otimização das condições de produção de ésteres etílicos a partir de óleo de peixe com elevado teor de ácidos graxos ômega-3

The production of ethyl esters by alcoholysis is an alternative for splitting triacylglycerols due to the possibility of using low temperatures, which results in oxidative protection of the polyunsaturated fatty acids. Ethyl esters produced under mild conditions of temperature could be used as substrate for obtaining structured lipids. The reaction parameters of production of ethyl esters from fish oil with high content of omega-3 fatty acids by alcoholysis were optimized using response surface methodology. An experimental design (2³) (with levels +1 and -1, six axial points with levels -alpha and +alpha and three central points) was applied. The variables investigated were concentration of catalyst, amount of ethyl alcohol and temperature. Ethyl ester conversion was monitored by high performance size exclusion chromatography (HPSEC) and the best result obtained was 95% conversion rate. The optimal conditions were 40 °C, 1% of NaOH and 36% of ethanol.

Propriedades elétricas e magnéticas de novos compostos com o ânion condutor [Ni(dmit)2]- e radicais magnéticos nitronil nitróxido

Three compounds have been synthesized with formulae [3-MeRad][Ni(dmit)2] (1), [4-MeRad][Ni(dmit)2] (2) and [4-PrRad][Ni(dmit)2] (3) where [Ni(dmit)2]- is an anionic pi-radical (dmit = 1,3-dithiol-2-thione-4,5-dithiolate) and [3-MeRad]+ is 3-N-methylpyridinium alpha-nitronyl nitroxide, [4-MeRad]+ is 4-N-methylpyridinium alpha-nitronyl nitroxide and [4-PrRad]+ is 4-N-propylpyridinium alpha-nitronyl nitroxide. The temperature-dependent magnetic susceptibility of 1 revealed that an antiferromagnetic interaction operates between the 3-MeRad+ radical cations with exchange coupling constants of J1 = - 1.72 cm-1 and antiferromagnetism assigned to the spin ladder chains of the Ni(dmit)2 radical anions. Compound 1 exhibits semiconducting behavior and 3 presents capacitor behavior in the temperature range studied (4 - 300 K).

Synthesis, characterization, DFT and Td-dfT study of the [Fe(mnt)(L)(t-BuNC) 2] octahedral complex (L = phen, bipy)

FeBr2 has reacted with an equivalent of mnt2- (mnt = cis-1,2-dicyanoethylene-1,2-dithiolate) and the α-diimine L (L = 1,10'-phenantroline, 2,2'-bipyridine) in THF solution, and followed by adding of t-butyl-isocyanide to give [Fe(mnt)(L)(t-BuNC)2] neutral compound. The products were characterized by infrared, UV-visible and Mössbauer spectroscopy, besides thermogravimetric and conductivity data. The geometry in the equilibrium was calculated by the density functional theory and the electronic spectrum by the time-dependent. The experimental and theoretical results in good agreement have defined an octahedral geometry with two isocyanide neighbours. The π→π* intraligand electronic transition was not observed for cis-isomers in the near-IR spectral region.

Uso de perfis cromatográficos de voláteis de cafés arábicas torrados para a diferenciação das amostras segundo o sabor, o aroma e a qualidade global da bebida

In this work, the volatile chromatographic profiles of roasted Arabica coffees, previously analyzed for their sensorial attributes, were explored by principal component analysis. The volatile extraction technique used was the solid phase microextraction. The correlation optimized warping algorithm was used to align the gas chromatographic profiles. Fifty four compounds were found to be related to the sensorial attributes investigated. The volatiles pyrrole, 1-methyl-pyrrole, cyclopentanone, dihydro-2-methyl-3-furanone, furfural, 2-ethyl-5-methyl-pyrazine, 2-etenyl-n-methyl-pyrazine, 5-methyl-2-propionyl-furan compounds were important for the differentiation of coffee beverage according to the flavour, cleanliness and overall quality. Two figures of merit, sensitivity and specificity (or selectivity), were used to interpret the sensory attributes studied.

Atribuição absoluta e geral de isômeros constitucionais por espectrometria de massas: o caso das metilpiperidinas

An absolute method is described via mass spectrometry (MS) for the structural assignment of isomers within the class of methylpiperidines. The method explores both the unimolecular and bimolecular gas phase behavior of structurally diagnostic fragment ions (SDFI). For the methylpiperidnes, the isomeric 2-methyl, 3-methyl and 4-methyl 2-azabutadienyl cations are found to function as SDFI. These fragment ions are expected to be formed from all members within the class, to be stable and to retain the structural information of the precursor molecule, and to not interconvert into one another. To characterize these SDFI, both the collision induced dissociation (CID) in argon and bimolecular ion/molecule chemistry with ethyl vinyl ether were compared.

Eficiência do processo de recobrimento de sementes de brócolos recobertas com polímero em leito de jorro

Broccoli seeds were coated in a conical-cylindrical spouted bed with an aqueous suspension of hydroxy ethyl cellulose aiming to improve the seeds coating technique using a fluid-dynamic process. An experimental design was applied to investigate the effects of the operating variables: gas temperature, atomizing air pressure and suspension flow rate on the germination of the seeds and on the process efficiency. Results indicated that the operating variables affect both the coating process efficiency and the germination ability. However, the analysis didn t identify differences between the germination potential of coated and uncoated seeds. Coated seeds absorbed up to 10 percent less moisture than the uncoated ones, when the environment temperature and humidity were controlled over a period of time.

Diabetologia intervencional: uma nova abordagem para o tratamento cirúrgico do diabetes tipo 2

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