Advances in chitosan and chitosan derivatives for biomedical applications in tissue engineering: An updated review.

In recent years, chitosan (CS) has received much attention as a functional biopolymer for various applications, especially in the biomedical field. It is a natural polysaccharide created by the chemical deacetylation of chitin (CT) that is nontoxic, biocompatible, and biodegradable. This natural polymer is difficult to process; however, chemical modification of the CS backbone allows improved use of functional derivatives. CS and its derivatives are used to prepare hydrogels, membranes, scaffolds, fibers, foams, and sponges, primarily for regenerative medicine. Tissue engineering (TE), currently one of the fastest-growing fields in the life sciences, primarily aims to restore or replace lost or damaged organs and tissues using supports that, combined with cells and biomolecules, generate new tissue. In this sense, the growing interest in the application of biomaterials based on CS and some of its derivatives is justifiable. This review aims to summarize the most important recent advances in developing biomaterials based on CS and its derivatives and to study their synthesis, characterization, and applications in the biomedical field, especially in the TE area.

Combined use of novel chitosan-grafted N-hydroxyethyl acrylamide polyurethane and human dermal fibroblasts as a construct for in vitro-engineered skin.

A rich plethora of information about grafted chitosan (CS) for medical use has been reported. The capability of CS-grafted poly(N-hydroxyethyl acrylamide) (CS-g-PHEAA) to support human dermal fibroblasts (HDFs) in vitro has been proven. However, CS-grafted copolymers lack good stiffness and the characteristic microstructure of a cellular matrix. In addition, whether CS-g-PHEAA can be used to prepare a scaffold with a suitable morphology and mechanical properties for skin tissue engineering (STE) is unclear. This study aimed to show for the first time that step-growth polymerizations can be used to obtain polyurethane (PU) platforms of CS-g-PHEAA, which can also have enhanced microhardness and be suitable for in vitro cell culture. The PU prepolymers were prepared from grafted CS, polyethylene glycol, and 1,6-hexamethylene diisocyanate. The results proved that a poly(saccharide-urethane) [(CS-g-PHEAA)-PU] could be successfully synthesized with a more suitable microarchitecture, thermal properties, and topology than CS-PU for the dynamic culturing of fibroblasts. Cytotoxicity, proliferation, histological and immunophenotype assessments revealed significantly higher biocompatibility and cell proliferation of the derivative concerning the controls. Cells cultured on (CS-g-PHEAA)-PU displayed a quiescent state compared to those cultured on CS-PU, which showed an activated phenotype. These findings may be critical factors in future studies establishing wound dressing models.

Estimación de brechas de geriatras en Chile / Estimation of geriatrician gaps in Chile

Antecedentes: el envejecimiento de la población chilena y la transición epidemiológica que atraviesa el país, ha incrementado la necesidad de formar, entre otros especialistas, a médicos geriatras. Objetivo: estimar la brecha de geriatras en Chile de acuerdo con necesidades epidemiológicas de la población de 65 años y más. Método: se realizó una estimación de brecha de horas de geriatra para la red de salud, a partir de una consulta a 57 geriatras de laboralmente activos de un total de 156 geriatras registrados a enero del 2021. En dicha consulta se indagó sobre tiempo de duración de consulta y frecuencia de consultas ideales de acuerdo con la capacidad funcional de las personas mayores a nivel nacional y por región obtenida de la encuesta Casen 2017. Resultados: a febrero del 2022 existe un total de 162 geriatras en Chile, cifra que equivale a un geriatra por cada 15.806 personas de 65 años y más. De acuerdo con la estimación realizada, se requeriría en Chile, un total de 1.244.689 horas de geriatra anual, equivalentes a la existencia de 589 geriatras a nivel nacional. Conclusión: según los resultados del estudio, a nivel nacional se necesitarían de un total de 589 geriatras para cubrir las necesidades de atención de las personas mayores con algún nivel de dependencia. De acuerdo con estas cifras, al primer trimestre del 2022 el país presentaría una brecha de 427 geriatras. Ante lo elevada de esta brecha, se cree necesario avanzar en estrategias de formación general en geriatría y gerontología en los equipos de salud y socio-sanitarios.

Background:The ageing between the Chilean population and the epidemiological transition that the country is going through has increased the need to train, among other specialists, geriatric doctors.Objective: To estimate the gap between geriatricians in Chile according to the epidemiological needs of the population aged 65 years and over. Method:An estimate of the gap in geriatrician hours was made for the health network based on a consultation of 57 active geriatricians out of 156 registered as of January 2021. In this consultation, the duration and frequency of ideal consultations were inquired according to the functional capacity of the elderly at the national level and by region obtained from the Casen 2017 survey.Results: as of February 2022, there are 162 geriatricians in Chile, equivalent to one geriatrician for every 15,806 people aged 65 years and over. According to the estimate, a total of 1,244,689 hours of annual geriatrician would be required in Chile, equivalent to 589 geriatricians nationwide. Conclusion:According to the study's results, at the national level, a total of 589 geriatricians would be needed to cover the care needs of older people with some level of dependen-ce. According to these figures, in the first quarter of 2022, the country would present a gap of 427 geriatricians. Given the highness of this gap, it is believed necessary to advance general training strategies in geriatrics and gerontology in health and socio-health teams

The Methylene Spacer Matters: The Structural and Luminescent Effects of Positional Isomerism of n-Methylpyridyltriazole Carboxylate Semi-Rigid Ligands in the Structure of Zn(II) Based Coordination Polymers.

Two Zn(II) coordination polymers (CPs) based on n-methylpyridyltriazole carboxylate semi-rigid organic ligands (n-MPTC), with n = 3 (L1) and 4 (L2), have been prepared at the water n-butanol interphase by reacting Zn(NO3)2·4H2O with NaL1 and NaL2. This allows us to systematically investigate the influence of the isomeric positional effect on their structures. The organic ligands were obtained by saponification from their respective ester precursors ethyl-5-methyl-1-(pyridin-3-ylmethyl)-1H-1,2,3-triazole-4-carboxylate (P1) and ethyl-5-methyl-1-(pyridin-4-ylmethyl)-1H-1,2,3-triazole-4-carboxylate (P2), resulting in their corresponding sodium salt forms, 3-MPTC, and 4-MPTC. The structure of the Zn(II) CPs determined by single-crystal X-ray diffraction reveals that both CPs have 2D supramolecular hydrogen bond networks. The 2D supramolecular network of [Zn(L1)]n (1) is built up by hydrogen bond interactions between oxygen and hydrogen atoms between neighboring n-methylpyridyltriazole molecules, whereas in [Zn(L2)·4H2O]n (2) the water molecules link 1D polymeric chains forming a 2D supramolecular aggregate. The structures of 1 and 2 clearly show that the isomeric effect in the semi-rigid ligands plays a vital role in constructing the Zn(II) coordination polymers, helped by the presence of the methylene spacer group, in the final structural conformation. The structures of 1 and 2 significantly affect their luminescent properties. Thus, while 2 shows strong emission at room temperature centered at 367 nm, the emission of 1 is quenched substantially.

Frecuencia del dolor anterior de rodilla luego de reconstrucción del ligamento cruzado anterior con autoinjerto hueso-tendón-hueso / Frequency of anterior knee pain following anterior cruciate ligament reconstruction with bone-tendon-bone autograft

Introducción. La ruptura del ligamento anterior cruzado (LCA) es una condición frecuente a nivel global y la reconstrucción artroscópica con autoinjerto de hueso-tendón-hueso (HTH) constituye una de las técnicas quirúrgicas para su tratamiento. No obstante, esta técnica puede generar complicaciones como dolor anterior de rodilla. Actualmente, se desconoce su prevalencia en Colombia.Objetivo. Determinar la frecuencia de dolor anterior de rodilla luego de la reconstrucción de LCA con autoinjerto HTH en pacientes operados en un periodo de 4 años en el Hospital San José en Bogotá, Colombia.Metodología. Estudio descriptivo realizado en pacientes con diagnóstico de ruptura del LCA llevados a cirugía de reconstrucción de este ligamento mediante HTH entre enero de 2014 y diciembre de 2017. Se realizó una encuesta telefónica y, en los pacientes con dolor, una valoración clínica para caracterizar dicho dolor. Los datos se describen usando frecuencias absolutas y relativas, así como medianas y rangos.Resultados. Se incluyeron 257 pacientes, la mayoría de los cuales eran hombres (87,5%) y adultos jóvenes (42,4%). La prevalencia del dolor anterior de rodilla fue 11,6%. Además, ninguno de los pacientes operados en 2014 presentó dolor anterior de rodilla en el momento de la valoración (a 4 o más años de seguimiento).Conclusiones. La reconstrucción del LCA mediante HTH es una técnica quirúrgica que ofrece excelentes resultados en términos de escalas funcionales y estabilidad de la rodilla. La prevalencia de dolor anterior de rodilla fue inferior a la reportada en otros estudios y se localizó con mayor frecuencia en el sitio donante (polo inferior de la rótula y tuberosidad tibial anterior)

Introduction. Anterior cruciate ligament (ACL) injury is a common condition worldwide, and one of the surgical techniques used to treat it is arthroscopic reconstruction with bone-tendon-bone (BTB) autograft. However, this technique can result in complications such as anterior knee pain, but its prevalence in Colombia is currently unknown.Objective. To establish the frequency of anterior knee pain after ACL reconstruction using BTB autograft in patients operated on over a 4-year period at the Hospital San José in Bogotá, Colombia.Methodology. Descriptive study performed in patients diagnosed with ACL injury and taken to ACL reconstruction surgery using BTB autograft between January 2014 and December 2017. A telephone survey and a clinical assessment were performed to characterize pain in patients presenting with this symptom. Data are described using absolute and relative frequencies, as well as medians and ranges.Results. A total of 257 patients were included, most of whom were male (87.5%) and young adults (42.4%). The prevalence of anterior knee pain was 11.6%. Moreover, none of the patients operated on in 2014 had anterior knee pain at the time of assessment (at 4 or more years of follow-up).Conclusions. ACL reconstruction using BTB autograft is a surgical technique that offers outstanding outcomes in terms of functional scales and knee stability. The frequency of anterior knee pain was lower than reported in other studies and was more frequently located at the donor site (lower pole of the patella and anterior tibial tuberosity)

COVID-19 y personas mayores en Chile: lecciones de dos años de pandemia / The impact of COVID-19 on the health status of older people in Chile

The article presents the main impact of COVID-19 pandemic on the health status of older people, systematizing the information about the direct impact of the pandemic in terms of number of cases, hospitalizations, deaths, the policies implemented for the prevention and management of COVID-19 in older people and the indirect impact of the two years of pandemic. Adopting a broad definition of health, the need to monitor and recover health care of older people is highlighted. The recovery of their functionality and mental health must be emphasized. The policies towards institutionalized older people must be revised. These areas should be the focus of health care policies for older people in Chile.

[The impact of COVID-19 on the health status of older people in Chile]. / COVID-19 y personas mayores en Chile: lecciones de dos años de pandemia.

The article presents the main impact of COVID-19 pandemic on the health status of older people, systematizing the information about the direct impact of the pandemic in terms of number of cases, hospitalizations, deaths, the policies implemented for the prevention and management of COVID-19 in older people and the indirect impact of the two years of pandemic. Adopting a broad definition of health, the need to monitor and recover health care of older people is highlighted. The recovery of their functionality and mental health must be emphasized. The policies towards institutionalized older people must be revised. These areas should be the focus of health care policies for older people in Chile.

Optic neuritis after COVID-19 vaccine application.

As the COVID-19 pandemic continues to rise, the development of effective vaccines is of crucial importance to prevent further morbidity and mortality. In parallel, some rare adverse events related to COVID-19 vaccines, have been reported, most of them mild. Here we report the case of a previously healthy 19-year-old woman who developed optic neuritis 1 week after single dose of Ad26.COV2.S vaccine with marked improvement after management with steroids. Although causality cannot be confirmed due to lack of a biological marker, this case may help to guide further research for potential pathogenic mechanism.

Prevalencia de ß-lactamasas de espectro extendido en Escherichia coli y Klebsiella pneumoniae identificados en una institución de salud en Barranquilla / Prevalence of extended spectrum ß-lactamases in Escherichia coli and Klebsiella pneumoniae identified in a health institution in Barranquilla

Introducción: Uno de los mecanismos de resistencia en Gram negativos es la producción de ß-lactamasas de espectro extendido (BLEE), capaces de otorgar resistencia a penicilinas y cefalosporinas. Objetivo. Determinar la prevalencia de ß-lactamasas de amplio espectro en aislamientos de Escherichia coli y Klebsiella pneumoniae identificados en una institución de salud. Metodología: Se tomaron los resultados del laboratorio clínico de los pacientes hospitalizados por enfermedades infecciosas identificados en un hospital de 4º nivel de complejidad en Barranquilla durante el año 2018 asociados a E. coli y K. pneumoniae, y se evaluó la resistencia de los mismos. Resultados: De 471 aislamientos identificados en diversas muestras clínicas, 317 están asociados a E. coli, y para ambos microorganismos presentaron mayores porcentajes de resistencias al tratamiento antibiótico en áreas no UCI, y evidenciando una resistencia a fármacos como ampicilina y cefalotina, por debajo de 60%, y 75%, respectivamente. Conclusión: Estas bacterias evaluadas, al ser de mayor relevancia clínica, pueden lograr un impacto no deseado por su presencia en áreas no UCI, siendo crítico para E. coli con resistencia a cefalosporinas de tercera y cuarta generación.

Introduction: One of the resistance mechanisms in Gram negative is the production of extended spectrum ß-lactamases (ESBL), capable of conferring resistance to penicillins and cephalosporins. Objective: To determine the prevalence of broad-spectrum ß-lactamases in Escherichia coli and Klebsiella pneumoniae isolates identified in a health institution. Methodology: Results were taken from the clinical laboratory of patients hospitalized for infectious diseases identified in a 4th level hospital in Barranquilla during 2018 associated with E. coli and K. pneumoniae, and their resistance was evaluated. Results: Of 471 isolates identified in various clinical samples, 317 are associated with E. coli, and for both microorganisms they presented higher percentages of resistance to antibiotic treatment in non-ICU areas, and showing resistance to drugs such as ampicillin and cephalothin, below 60%, and 75%, respectively. Conclusion: These evaluated bacteria, being of greater clinical relevance, can achieve an unwanted impact due to their presence in non-ICU areas, being critical for E. coli with resistance to third and fourth generation cephalosporins.

Crystallization Induced Enhanced Emission in Two New Zn(II) and Cd(II) Supramolecular Coordination Complexes with the 1-(3,4-Dimethylphenyl)-5-Methyl-1H-1,2,3-Triazole-4-Carboxylate Ligand.

Two new d10 metal supramolecular metal-organic frameworks (SMOFs) with general formula [ML2(H2O)2]n (M = Zn, Cd) have been synthetized using the sodium salt of the anionic 1-(3,4-dimethylphenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylate ligand (Na+L-). Both SMOFs have been structurally characterized by single-crystal X-ray diffraction analysis and IR spectroscopy. The compounds are isostructural and form supramolecular aggregates via hydrogen bonds with the presence of less common dihydrogen bonds. Interestingly, they show ionic conductivity and porosity. The luminescent properties have been also studied by means of the excitation and emission spectra. Periodic DFT and molecular TD-DFT calculations have been used to unravel the emergence of luminescence in the otherwise non-emitting 1-(3,4-dimethylphenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylate ligand once incorporated in the SMOFs. Our results also illustrate the importance of considering the dielectric environment in the crystal when performing excited state calculations for isolated fragments to capture the correct electronic character of the low-lying states, a practice which is not commonly adopted in the community.

Crystal Structure and Hirshfeld Surface Analysis of Acetoacetanilide Based Reaction Products.

We report an unprecedented multicomponent reaction of acetoacetanilide with malononitrile leading to a structurally novel bicyclic product (9) in a high yield. The structure has been confirmed by X-ray crystallography and comparative Hirshfeld surface analysis of 5-cyano-2-hydroxy-2-methyl-N-phenyl-4-(yridine-4-yl)-6-(thiophen-2-yl)-3,4-dihydro-2H-pyran-3-carboxamide 2, 5-cyano-2-hydroxy-2-methyl-6-oxo-N-phenyl-4-(thiophen-2-yl)piperidine-3-carboxamide 4 and 2-(8-amino-7,8a-dicyano-1-imino-4a-methyl-3-oxo-2-phenyl-1,3,4,4a,5,8a-hexahydroisoquinolin-6(2H)-ylidene)-N-phenylacetamide 9.

Hydrogen and halogen bonding in the haloetherification products in chalcone.

Cooperative action of hydrogen and halogen bonding in the reaction of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-1-phenylprop-2-en-1-one with HCl or HBr in alcohol medium under microwave irradiation (20 W, 80 °C, 10 min) allows the isolation of the haloetherification products (2S,3S)-3-(3-tert-butyl-5-chloro-4-hydroxyphenyl)-2-chloro-3-ethoxy-1-phenylpropan-1-one, C21H24Cl2O3, (2S,3S)-2-bromo-3-(3-tert-butyl-5-bromo-4-hydroxyphenyl)-3-methoxy-1-phenylpropan-1-one, C20H22Br2O3, and (2S,3S)-2-bromo-3-(3-tert-butyl-5-bromo-4-hydroxyphenyl)-3-ethoxy-1-phenylpropan-1-one, C21H24Br2O3, in good yields. Both types of noncovalent interactions, e.g. hydrogen and halogen bonds, are formed to stabilize the obtained products in the solid state.

Application of process system engineering tools to the fed-batch production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from a vinasses-molasses Mixture.

Fed-batch production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer using vinasses-molasses mixture is carried out in this work by implementing different process systems engineering tools. Two fed-batch strategies are tested experimentally at 5 L scale, considering only offline information: (1) offline optimizing control and (2) exponential feeding. Application of these strategies showed that different feeding profiles result in different dynamic behaviour, influencing both, yield and biopolymer properties. As offline-based feeding strategies do not consider information of the culture status, they cannot deal with uncertainties. Therefore, a closed loop control strategy was implemented, which uses biomass and substrate information predicted online by soft-sensors. Results demonstrated the technical feasibility to produce biopolymer using a 75/25%vol. vinasses-molasses mixture. Successful implementation of the soft-sensor-based control strategy was evidenced at pilot plant scale, where sugar concentration was kept almost constant for 14 h, while obtaining the desired copolymer. Thus, proposed control strategy could be of interest at industrial-scale.

The Positional Isomeric Effect on the Structural Diversity of Cd(II) Coordination Polymers, Using Flexible Positional Isomeric Ligands Containing Pyridyl, Triazole, and Carboxylate Fragments.

To systematically investigate the influence of the positional isomeric effect on the structures of polymer complexes, we prepared two new polymers containing the two positional isomers ethyl 5-methyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-3-carboxylate (L1) and ethyl-5-methyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-4-carboxylate (L2), as well as Cd(II) ions. The structures of the metal⁻organic frameworks were determined by a single crystal XRD analysis. The compound [Cd(L1)2·4H2O] (1), is a hydrogen bond-induced coordination polymer, whereas the compound [Cd(L2)4·5H2O]n (2) is a three-dimensional (3-D) coordination polymer. Their structures and properties are tuned by the variable N-donor positions of the ligand isomers. This work indicates that the isomeric effect of the ligand isomers plays an important role in the construction of the Cd(II) complexes. In addition, the thermal and luminescent properties are reported in detail.

Self-Assembly of Discrete Metallocycles versus Coordination Polymers Based on Cu(I) and Ag(I) Ions and Flexible Ligands: Structural Diversification and Luminescent Properties.

Three new Ag(I) and one Cu(I) coordination compounds with two different positional isomers, propane-1,3-diyl bis(pyridine-4-carboxylate) (L1) and propane-1,3-diyl bis(pyridine-3-carboxylate) (L2), of a bis-(pyridyl-carboxylate) ligand have been synthesized. X-ray diffraction analysis revealed that the self-assembly of L1 with AgCF3SO3 and AgClO4 salts leads to the formation of discrete binuclear metallocycles {Ag(L1)CF3SO3}2 (1) and {Ag(L1)ClO4}2 (2), respectively. However, self-assembly of the other ligand, L2, with AgCF3SO3 and CuCl salts, results in a 1-D zig-zag chain {Ag(L2)CF3SO3}∞ (3) and a 1-D double-stranded helical chain {Cu2Cl2(L2)2}∞ (4) coordination polymers, respectively. Solid emission spectra recorded at room temperature show interesting luminescence properties for all four compounds in the range from 438 to 550 nm, especially for compound 4 that was found to change its emission color when the wavelength of the excitation radiation is switched from 332 to 436 nm.

Withanolides from three species of the genus Deprea (Solanaceae). Chemotaxonomical considerations.

Nine withanolides were isolated from the aerial parts of Deprea bitteriana, Depreacuyacensis, and Depreazamorae. D.bitteriana yielded two withaphysalins, D. cuyacensis gave two 13,14-seco withaphysalins, while D. zamorae yielded five physangulidines. The compounds were fully characterized by a combination of spectroscopic methods (1D and 2D NMR and MS). All compounds isolated from D.bitteriana and D. cuyacensis were obtained as epimeric mixtures at C-18. The structure of physangulidine D was confirmed by X-ray diffraction analysis. The skeletons found in this research support the chemotaxonomical position of the genus Deprea in the tribe Physalideae.

Producción de etanol a partir de yuca en condiciones de alta concentración de sólidos (VHG) / Ethanol production from cassava using very high gravity conditions (VHG)

La investigación realizada evalúa el efecto del medio fermentativo y la concentración de azúcares iniciales sobre la producción de etanol en sistemas batch, cuando se emplean sacarificados de harina de yuca (Manihot esculenta), como fuente de carbono. El diseño experimental ejecutado fue de tipo bifactorial de efectos fijos y analiza la productividad de bioetanol en cuatro medios fermentativos diferentes, dos de los cuales se suplementaron con sacarificados de harina de yuca variedad Copiblanca. Las concentraciones de azúcares iniciales evaluadas en estos sustratos fueron de 250, 300 y 350 g/L. Estos tratamientos fermentativos fueron inoculados con una variedad etanologénica comercial de S. cerevisiae a una concentración de 0.05% (p/v). Las condiciones de proceso incluyeron un volumen final de 150 mL, una incubación a 35°C por 48 horas, agitación constante de 150 rpm y pH entre 4.0 y 4.5. Los sacarificados provenientes de esta variedad de yuca usados como fuente de carbono, mostraron ser excelentes sustratos para la obtención de etanol. Se evidenciaron aumentos de más del 500% en términos de productividad volumétrica con respecto al control experimental y se alcanzaron concentraciones finales de etanol del 14.7%v/v, asociadas a rendimientos producto/sustrato de 0,48 g/g y productividades de 2,4 g/L/h. Estos parámetros cinéticos fueron logrados con el medio fermentativo más simple evaluado, medio compuesto por los sacarificados como fuente de carbono y como única fuente nutricional, bajo concentraciones de azúcares iniciales de 250g/L; lo que demuestra la aptitud de estos sustratos para efectos de producción etanólica.

This research exposes the fermentative medium and initial sugar concentration effect on ethanol production in batch systems, when used glucose syrups derivatives of cassava (Manihot esculenta), as a carbon source. The experimental design was factorial and analyzes the productivity of bioethanol in four different fermentation media, two of which were supplemented with cassava flour sugared. The initial sugar concentrations tested on these substrates were 250, 300 and 350 g / L. These fermentative treatments were inoculated with a commercial ethanolic variety of S. cerevisiae at a concentration of 0.05% (w / v). The process conditions included a final volume of 150 mL, incubation at 35 ° C for 48 hours , constant stirring at 150 rpm and pH between 4.0 and 4.5. The saccharified from this cassava variety showed be excellent substrate for the bioethanol production, achieving increases of 550% in terms of volumetric productivity over the control experiment, the above, allowed us to achieve final concentrations of ethanol of 14.7% v / v, yields product / substrate of 0.5 g / g, and productivities of 2.4 g / L / h. Most interesting is that these kinetic parameters were achieved with the simplest fermentation medium evaluated, the mean was compound of saccharified as a carbon source and as a sole source of nutrition, and its initial concentration of sugars was 250g / L; the above shows the ability of these substrates for ethanol production purposes.

Ultrasound-assisted phase-transfer catalysis method in an aqueous medium to promote the Knoevenagel reaction: advantages over the conventional and microwave-assisted solvent-free/catalyst-free method.

Given the broad spectrum of uses of acrylonitrile derivatives as fluorescent probes, AChE inhibitors, and others, it is necessary to find easy, efficient and simple methods to synthesize and diversify these compounds. We report the results of a comparative study of the effects of three techniques on the reactions between heterocyclic aldehydes and 2-(benzo[d]thiazol-2-yl)acetonitrile: stirring; ultrasound coupled to PTC conditions (US-PTC); and MW irradiation (MWI) under solvent and catalyst-free conditions. The effects of conditions on reaction parameters were evaluated and compared in terms of reaction time, yield, purity and outcomes. The US-PTC method is more efficient than the MWI and conventional methods. The reaction times were considerably shorter, with high yields (>90%) and good levels of purity. In addition, X-ray diffraction analysis and quantum mechanical calculations, at the level of density functional theory (DFT), ratify obtaining acrylonitrile isomers with E configurations. The crystal structure of 3c is stabilized by weak C-Ho⋯N intermolecular interactions (Ho⋯NC=2.45 Å, Co⋯NC=3.348(3) Å, Ho⋯NC=162°), forming centrosymmetric ring R2(2) (20) along the crystallographic a axis.

A classical simulation of nonlinear Jaynes-Cummings and Rabi models in photonic lattices: reply to comment.

We regret that such a misleading comment [Opt. Express (2013)] has been made to our paper. First Lo states in his abstract that "However, the nonlinear Rabi model has already been rigorously proven to be undefined" to later recoil and use the contradictory statement "(. . . ) regarding the BS model with the counter-rotating terms (. . . ) Lo and his co-authors have proven that the model is well defined only if the coupling stregth g is smaller than a critical value gc = ω/4". While Lo focuses on the validity of the quantum optics Hamiltonians and gives a misleading assesment of our manuscript, the focus of our paper is the method to map such a set of Hamiltonians from quantum optics to photonic lattices. Our method is valid for the given class of Hamiltonians and, indeed, precaution must be exerted on the paramater ranges where those Hamiltonians are valid and where their classical simulation is feasible. These parameter ranges have to be specified in for each particular case studied. Furthermore, we gave as example the Buck-Sukumar model including counter-rotating terms which is a valid Hamiltonian for some coupling parameters.