Conformational Landscape of α-Halopropiophenones Determined by nJC-H NMR Reveals Unexpected Patterns and Geometric Constraints.

The conformational features of α-halopropiophenones were investigated to understand the influence of α-halogens on conformation through hyperconjugative interactions, electrostatics, and steric factors. Using NMR, C-H scalar coupling constants were measured in different solvents, revealing a pattern in the conformational equilibria, which we validated by computational means. This behavior arises largely from hyperconjugative effects with the exception of the fluoro-derivatives, which are also influenced by steric and electrostatic interactions. In all cases, the contribution to hyperconjugation of the α-halo ketones is driven by the oxygen lone pair (rather than the C-X bond), which donates electron density to the adjacent C-C bonds. Additionally, C-Cα bond rotation generates distortions in the side chain, responsible for destabilization, thus affecting system conjugation. These structural features identified for the α-halo ketones are also reflected in their reactivity, which is distinct from that expected for nucleophilic addition.

Next-Generation Tags for Fluorine Nuclear Magnetic Resonance: Designing Amplification of Chemical Shift Sensitivity.

Fluorine NMR is a highly sensitive technique for delineating the conformational states of biomolecules and has shown great utility in drug screening and in understanding protein function. Current fluorinated protein tags leverage the intrinsic chemical shift sensitivity of the 19F nucleus to detect subtle changes in protein conformation and topology. This chemical shift sensitivity can be amplified by embedding the fluorine or trifluoromethyl reporter within a pyridone. Due to their polarizability and rapid tautomerization, pyridones exhibit a greater range of electron delocalization and correspondingly greater 19F NMR chemical shift dispersion. To assess the chemical shift sensitivity of these tautomeric probes to the local environment, 19F NMR spectra of all possible monofluorinated and trifluoromethyl-tagged versions of 2-pyridone were recorded in methanol/water mixtures ranging from 100% methanol to 100% water. 4-Fluoro-2-pyridone and 6-(trifluoromethyl)-2-pyridone (6-TFP) displayed the greatest sensitivity of the monofluorinated and trifluoromethylated pyridones, exceeding that of known conventional CF3 reporters. To evaluate the utility of tautomeric pyridone tags for 19F NMR of biomolecules, the alpha subunit of the stimulatory G protein (Gsα) and human serum albumin (HSA) were each labeled with a thiol-reactive derivative of 6-TFP and the spectra were recorded as a function of various adjuvants and drugs. The tautomeric tag outperformed the conventional tag, 2-bromo-N-(4-(trifluoromethyl)phenyl)acetamide through the improved resolution of several functional states.

Controlled Pyrazole-Hydrazone Annulation: Regiodivergent Synthesis of 1H- and 2H-Pyrazolo[3,4-d]pyridazinones.

An efficient and controlled site-selective annulation of 3,5-diethoxycarbonyl 4-hydrazonyl pyrazoles is described. The relative proportion of the products is affected by hydrazone intermediate configuration, reaction temperature, and Lewis acid employed. At a temperature of 110-120 °C, the reaction preferentially afforded 1H-pyrazolo[3,4-d]pyridazin-7(6H)-ones, whereas using Yb(OTf)3 in MeCN reflux, 2H-pyrazolo[3,4-d]pyridazin-7(6H)-ones were favored. Computational investigations were performed to clarify the mechanism and the origin of the regiodivergence.

Resveratrol reverses male reproductive damage in rats exposed to nicotine during the intrauterine phase and breastfeeding.

BACKGROUND: Nicotine leads to reproductive changes culminating in male infertility and subfertility. Resveratrol, a polyphenol, is a biological modulator. Sirtuin 1 (SIRT1) protein can positively act on male reproduction, and its expression can be affected by nicotine and modulated by resveratrol. OBJECTIVES: The capability of resveratrol to reverse the reproductive damage in adult male offspring, which was nicotine-exposed during the intrauterine phase and breastfeeding, was investigated. MATERIALS AND METHODS: Four groups were established with male offspring born from nicotine-exposed and non-exposed rat dams during pregnancy and lactation. Forty-eight male Wistar rats were distributed into four groups: sham control (SC), resveratrol (R), nicotine (N), and nicotine + resveratrol (NR). Rat dams of the N and NR offspring were exposed to nicotine (2 mg/kg/day) during pregnancy and lactation using a subcutaneously implanted minipump. The offspring of the R and NR groups received resveratrol (300 mg/kg of body weight, gavage) for 63 days from puberty. At 114 days of age, the male rats were euthanized. RESULTS: Nicotine did not alter the body weight, biometry of reproductive organs, or quantitative sperm parameters of adult offspring but caused an evident worsening of all sperm qualitative parameters studied. Daily treatment with resveratrol from puberty up to adulthood improved all qualitative sperm parameters significantly, leading some of them close to the control values. Resveratrol also improved the morphological integrity and expression of SIRT1 in the seminiferous epithelium of nicotine-exposed offspring. CONCLUSION AND DISCUSSION: Resveratrol reversed the male reproductive damage caused by nicotine. Nicotine crosses the blood-placental membrane and is present in the breast milk of mothers who smoke. Resveratrol restored the altered reproductive parameters in the male adult offspring that were nicotine-exposed during intrauterine life and breastfeeding. The epigenetic modulating action of resveratrol can be involved in this nicotine damage reversion. Resveratrol may be a promising candidate to be investigated regarding the adjuvant strategies in the treatment of male infertility.

A produção do conhecimento em psicologiaa partir das experiências de mulheres negras diaspóricas. Aspectos teórico-metodológicos / The production of knowledge in psychology from the experiences of diasporic black women. Theoretical-methodological aspects

Partindo das experiências de mulheres negras diaspóricas, problematizamos aspectos teórico-metodológicos da produção do conhecimento científico na psicologia, com o intuito de enfrentar o racismo genderizado e o epistemicídio. Tomamos como base analítica os desafios vivenciados em duas pesquisas nas quais as experiências de mulheres negras diaspóricas foram centrais para a compreensão das dinâmicas de opressão. Insurgimos contra modelos teórico-metodológicos pautados em uma racionalidade científica produtora de uma humanidade universalizante de matriz eurocêntrica, que se sustenta em noções colonizadas, excludentes e genocidas de produção de conhecimento. Compartilhamos, a partir do diálogo e da articulação de vozes negras e decoloniais, outros caminhos possíveis para a práxis científica psi em que corpos, vozes e escritas marginalizadas atuam como faróis a conduzir quizumbas e caos fomentadores de criticidade, criatividade e novas insurgências teórico-metodológicos, visando transformar a ciência de modo a destruir seus muros e construir novas pontes.(AU)

Based on the experiences of black women, we problematize theoretical and methodological aspects of the production of scientific knowledge in psychology, in order to face gendered racism and epistemicide. We take as an analytical basis two researches in which the experiences of black diasporic women are central to understanding the dynamics of oppression. We argue against theoretical and methodological models based on a scientific rationality that produces a universalizing humanity with a Eurocentric matrix,which is based on colonized, exclusionary and genocidal notions. knowledge production. We share with the dialogue and articulation of black and decolonial voices, other possible paths for psi scientific praxis in which marginalized bodies, voices and writings act as beacons to lead quizumbas and chaos that foster criticality, creativity and new theoretical and methodological insurgencies, aiming at transform science in order to destroy its walls and build new bridges.(AU)

Conformational Isomerism of 3-Chalcogenomethyl-N-Methyl-2-Pyrrolidinones: Insights from NMR Spectroscopy and Molecular Modeling.

A conformational analysis of N-methyl-2-pyrrolidinone 3-substituted by methoxyl, thiomethoxyl, and selenomethoxyl is reported by means of 1H nuclear magnetic resonance spectroscopy and electronic structure calculations. The five-membered ring has an envelope conformation with the α-carbonyl substituent being able to assume two positions: pseudo-axial and pseudo-equatorial. In vacuum, the calculations pointed to the pseudo-axial conformer as the most stable one, and this preference increases with the size of the substituent and a decrease in its electronegativity. Natural bond orbital analysis evidenced the importance of electron delocalization on the stability, and a principal component of analysis (PCA) plot of the hyperconjugative interactions revealed the main ones. Steric and electrostatic effects were also investigated by energy decomposition analysis.

Shelf-life of guavas coated with biodegradable starch and cellulose-based films.

Guava is a perishable fruit susceptible to post-harvest losses. So, the development of biodegradable films based on acetylated cassava starch (ACS) and hydroxyethyl cellulose (HEC) could be an alternative to increase guavas (Psidium guajava L.) shelf life. Films were characterized by solubility, opacity, water vapor transport, and thickness. Mass loss, texture, titratable acidity, soluble solids, vitamin C, and skin color of the fruits were analyzed. The films with higher HEC concentration were more transparent and hygroscopic. Guava coated with 75% HEC and 25% ACS or 100% HEC films increased firmness, maintained green skin color and reduced ripeness, lasting for 13 days, ensuring that the ACS and HEC based films can increase guavas shelf life, besides decrease environmental impacts of non-biodegradable packages.

Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines.

The presence of strong stereoelectronic interactions involving the substituents in cis-2-substituted cyclohexanes may lead to results different from those expected. In this work, we studied the conformational behavior of cis-2-fluoro- (F), cis-2-chloro- (Cl), cis-2-bromo- (Br) and cis-2-iodocyclohexylamine (I) by dynamic NMR and theoretical calculations. The experimental data pointed to an equilibrium strongly shifted toward the ea conformer (equatorial amine group and axial halogen), with populations greater than 90% for F, Cl and Br in both dichloromethane-d 2 and methanol-d 4. Theoretical calculations (M06-2X/6-311++G(2df,2p)) were in agreement with the experimental, with no influence of the solvent or the halogen on the equilibrium. A principal component analysis of natural bond orbital energies pointed to the σ*C-X and σC-H orbitals and the halogen lone pairs (LPX) as the most significant for the hyperconjugative interactions that influenced the equilibrium. The σC-H → σ*C-X hyperconjugation and the interactions involving the LPX counterbalance each other, explaining the non-influence of the halogen on the conformational equilibrium. These interactions are responsible for the strong preference for the ea conformer in cis-2-halocyclohexylamines, being strong enough to restrain the shift in the equilibrium due to other factors such as steric repulsion or solvent effects.

Embates discursivos e significantes vazios nas manifestações de junho de 2013 / Discursive struggles and empty signifiers at the demonstrations of June 2013 / Confrontaciónes discursivas e significantes vacíos en las jornadas de junio de 2013

O objetivo deste trabalho é propor uma investigação sobre os embates discursivos entre diversas identidades políticas, encenados nas ruas e no espaço virtual, durante as manifestações realizadas nas capitais brasileiras durante o mês de junho de 2013. Através do pensamento de Ernesto Laclau (1994) e Chantal Mouffe (1990), especificamente em torno dos conceitos de “antagonismo” e “significantes vazios”, propõe-se uma análise de determinadas produções e recepções de enunciados do embate estabelecido entre os diversos grupos que participaram das manifestações realizadas nas capitais brasileiras durante o mês de junho de 2013. Os significantes vazios permitiram verificar a emergência de significados antagônicos nas produções discursivas surgidas nas ruas e nos ambientes virtuais como um modo de articulação de antagonismos e identidades políticas.

The goal of this paper is to propose an inquiry about the discursive struggle performed at the streets and at the virtual space among the many political identities present in the demonstrations of June 2013 in Brazil´s biggest cities. It is proposed an analysis of certain production and reception of utterances of the struggle established among the many groups that took part in the demonstration through the framework of Laclau´s and Mouffe´s concepts of “antagonism” and “empty signifiers”. The latter allowed us to verify the emergency of antagonistic meanings in the discursive production found in the streets and virtual spaces as a way to articulate antagonism and political identities. (AU)

El objetivo de este trabajo es proponer una investigación sobre las confrontaciónes discursivas entre diferentes identidades políticas, que tuvo lugar en las calles y en el espacio virtual, durante las manifestaciones celebradas en las capitales brasileñas durante el mes de junio de 2013. A través del pensamiento de Ernesto Laclau (1994) Chantal Mouffe (1990), específicamente en torno a los conceptos de "antagonismo" y "significantes vacíos", proponemos un análisis de cierta producción y recepción de enunciados en la confrontación que se estableció entre los distintos grupos que participaron de las manifestaciones que tuvieron lugar en las capitales brasileñas durante el junio de 2013. Los significantes vacíos han permitido verificar la emergência de significados antagónicos en las producciones discursivas surgidas en las calles y espácios virtuales como un modo de articulación antagonismos y las identidades políticas. (AU)

Embates discursivos e significantes vazios nas manifestações de junho de 2013 / Discursive struggles and empty signifiers at the demonstrations of june 2013 / Confrontaciónes discursivas e significantes vacíos en las jornadas de junio de 2013

O objetivo deste trabalho é propor uma investigação sobre os embates discursivos entre diversas identidades políticas, encenados nas ruas e no espaço virtual, durante as manifestações realizadas nas capitais brasileiras durante o mês de junho de 2013. Através do pensamento de Ernesto Laclau (1994) e Chantal Mouffe (1990), especificamente em torno dos conceitos de “antagonismo” e “significantes vazios”, propõe-se uma análise de determinadas produções e recepções de enunciados do embate estabelecido entre os diversos grupos que participaram das manifestações realizadas nas capitais brasileiras durante o mês de junho de 2013. Os significantes vazios permitiram verificar a emergência de significados antagônicos nas produções discursivas surgidas nas ruas e nos ambientes virtuais como um modo de articulação de antagonismos e identidades políticas.

The goal of this paper is to propose an inquiry about the discursive struggle performed at the streets and at the virtual space among the many political identities present in the demonstrations of June 2013 in Brazil´s biggest cities. It is proposed an analysis of certain production and reception of utterances of the struggle established among the many groups that took part in the demonstration through the framework of Laclau´s and Mouffe´s concepts of “antagonism” and “empty signifiers”. The latter allowed us to verify the emergency of antagonistic meanings in the discursive production found in the streets and virtual spaces as a way to articulate antagonism and political identities.

El objetivo de este trabajo es proponer una investigación sobre las confrontaciónes discursivas entre diferentes identidades políticas, que tuvo lugar en las calles y en el espacio virtual, durante las manifestaciones celebradas en las capitales brasileñas durante el mes de junio de 2013. A través del pensamiento de Ernesto Laclau (1994) Chantal Mouffe (1990), específicamente en torno a los conceptos de "antagonismo" y "significantes vacíos", proponemos un análisis de cierta producción y recepción de enunciados en la confrontación que se estableció entre los distintos grupos que participaron de las manifestaciones que tuvieron lugar en las capitales brasileñas durante el junio de 2013. Los significantes vacíos han permitido verificar la emergência de significados antagónicos en las producciones discursivas surgidas en las calles y espácios virtuales como un modo de articulación antagonismos y las identidades políticas.

Graphene oxide and titanium: synergistic effects on the biomineralization ability of osteoblast cultures.

Graphene oxide (GO) has attracted remarkable attention in recent years due to properties such as extremely large surface area, biocompatibility, biostability, and easy chemical functionalization. Osteoblasts underlie the deposition of hydroxyapatite crystals in the bone protein matrix during biomineralization; hydroxyapatite deposition involves extracellular matrix vesicles that are rich in alkaline phosphatase (ALP). Here, we have investigated how GO affects osteoblast viability, ALP activity, and mineralized matrix formation in osteoblast cultures in three different phases of cell growth, in the presence and in the absence of titanium (Ti). Scanning electron microscopy (SEM), Raman spectra, and energy dispersive spectroscopy aided GO characterization. The presence of GO increased the viability of osteoblast cells grown on a plastic surface. However, osteoblast viability on Ti discs was lower in the presence than in the absence of GO. ALP activity emerged at 14 days for the cell culture incubated with GO. The total protein concentration also increased at 21 days on both the Ti discs and plastic surface. Osteoblasts grown on Ti discs had increased mineralized matrix formation in the presence of GO as compared to the cells grown in the absence of GO. SEM images of the cell cultures on plastic surfaces in the presence of GO suggested delayed mineralized matrix formation. In conclusion, applications requiring the presence of Ti, such as prostheses and implants, should benefit from the use of GO, which may increase mineralized nodule formation, stimulate biomineralization, and accelerate bone regeneration.

The Co-4 locus on chromosome Pv08 contains a unique cluster of 18 COK-4 genes and is regulated by immune response in common bean.

KEY MESSAGE: The common bean locus Co - 4, traditionally referred to as an anthracnose-resistant gene, contains a cluster of predicted receptor-like kinases (COK-4 and CrRLK1-like), and at least two of these kinases are co-regulated with the plant's basal immunity. Genetic resistance to anthracnose, caused by the fungus Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara, is conferred by major loci throughout the Phaseolus vulgaris genome, named Co. The complex Co-4 locus was previously reported to have several copies of the COK-4 gene that is predicted to code for a receptor-like kinase (RLK). In general, plant RLKs are involved in pathogen perception and signal transduction; however, the molecular function of COK-4 remains elusive. Using newly identified molecular markers (PvTA25 and PvSNPCOK-4), the SAS13 marker, COK-4 sequences and phylogeny, and the recently released bean genome sequence, we determined the most probable boundaries of the Co-4 locus: a 325-Kbp region on chromosome Pv08. Out of the 49 predicted transcripts in that region, 24 encode for putative RLKs (including 18 COK-4 copies) with high similarity to members of the Catharanthus roseus RLK1-like (CrRLK1L) protein family from different plant species, including the well-described FERONIA (FER) and ANXUR. We also determined that two RLK-coding genes in the Co-4 locus (COK-4-3 and FER-like) are transcriptionally regulated when bean plants are challenged with the flg22 peptide, a commonly used elicitor of plant immunity, or the bacterium Pseudomonas syringae pv. phaseolicola, the causal agent of halo blight. While COK-4-3 is activated during immune response, FER-like is downregulated suggesting that these genes could play a role in plant responses to biotic stress. These results highlight the importance of dissecting the regulation and molecular function of individual genes within each locus, traditionally referred to as resistance gene based on genetic segregation analysis.