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This short paper analyses the concentrations of two major components (Fe, S) and eight trace elements (As, Au, Co, Cu, Hg, Ni, Mn, Zn) in soils and tailings from Tierra Amarilla (northern Chile) using ICP-Ms analysis. The levels of As, Au, Cu, Fe and S are very high and come from polymetallic sulphides from nearby mines, together with minor contributions of Co, Ni and Mn. Hg has its origin in the extreme seasonal flows of the Copiapó River, which erodes the dumps of old precious metal mines. These high concentrations require further analysis of possible metal immobilisation techniques, bioavailability or analysis in cultivated plants. [ABSTRACT FROM AUTHOR]

Mexico has three genetic breeding programs for peaches and nectarines (Prunus persica (L.) Batsch). The diversity of its germplasm at a DNA level is unknown. Therefore, the aims of this work were: 1) to characterize the diversity of three P. persica populations using microsatellites or simple sequence repeats (SSRs); 2) to genetically compare two P. persica populations from the Prunus breeding programs of the College of Postgraduates and the Center for Genetic Resources and Improvement; and 3) to extrapolate the use of these SSRs to other Prunus species. DNA was extracted from leaves of 162 individuals from three locations: Montecillo and Coatepec Harinas, State of Mexico, and Huimilpan, Querétaro. A CTAB-based protocol was used. The variation of six SSRs was examined in polyacrylamide, and the diversity statistics were obtained for loci and populations. On average, 10.8 alleles were found per locus, a polymorphic information content (PIC) of 0.66, genic diversity of 0.69, and heterozygosity of 0.49. The most polymorphic locus was UCDCH15, with a PIC of 0.84 for P. persica, and UCDCH14, with 0.9 for the other three Prunus species. Regarding P. persica populations, only five SSRs were polymorphic. The expected heterozygosity was 0.512, 0.719, and 0.621, and the observed heterozygosity was 0.334, 0.716, and 0.768 for Montecillo, Querétaro, and Coatepec Harinas, respectively, indicating that Querétaro is the most diverse, and Montecillo, the most homogenous. The similarity between Montecillo and Coatepec Harinas was 0.543, followed by Montecillo and Querétaro (0.47) and Coatepec Harinas and Querétaro (0.183). For the other Prunus species, the six SSRs were polymorphic, confirming that their use can be extrapolated to related species such as apricot (Prunus armeniaca L.), plums (P. salicina L.), and cherries (P. avium L.). This is the first report on diversity in P. persica and some related species by SSRs in Mexico. [ABSTRACT FROM AUTHOR]

The low quality of plants produced in nurseries has added to the high mortality rates in plantations established in Mexico. The objective of this study is to evaluate the effect of three sowing dates and the provenance of the germplasm on the plant quality of Pinus patula, in addition to evaluating the effectiveness of four pre-germination treatments: i) control, ii) soaking in water for 12-hour and storage at 3 °C for five weeks, plus 12-hour soaking before sowing, iii) storage at 3 °C for five weeks and 12-hour soaking before sowing, and iv) 12-hour soaking before sowing. The height, diameter at the root neck, robustness index, and germination efficiency of the provenance progenies of P. patula in the nursery were evaluated, in addition to daily and accumulated germination in the laboratory. Data were analyzed using ANOVA, Kruskal-Wallis tests, Tukey means, and Dunn's medians. In addition, the response variables were correlated with the bioclimatic variables of the provenances. Statistical differences were found in plant quality according to provenance. Families from Pinal de Amoles, Querétaro presented the lowest robustness index (6,61). The seeds had a higher germination (92,3 %) when soaked for 12 h and stored at 3 °C for five weeks, plus soaking in water for 12 h before sowing. The quality and germination of P. patula are influenced by its provenance, sowing date, and pregerminative treatments. [ABSTRACT FROM AUTHOR]

In asexual seed orchards, genetically improved seed is obtained to produce plants destined for forest plantation programs, which will help increase wood quality and productivity, and reduce cutting cycles. However, asexual seed orchards established in Mexico are not functional and many aspects of their reproductive characteristics remain unknown. The objective of this study was to evaluate the survival, height increase, and vegetative and production (presence) of strobili in juvenile ramets from an asexual seed orchard of Pinus patula owing to the effect of the geographical origin of the ortets. The response variables were statistically analyzed using ANOVA, and when significant differences existed (P < 0.05), Tukey's mean test was used. Furthermore, using the Pearson test, the correlation between the characteristics evaluated and the bioclimatic variables of the origin of the ortets was determined. Statistical differences were found in survival due to the geographical origin of the ortets and the cloned tree, but not in the other variables. The highest survival was found in ramets with scions from ortets of Tlahuiltepa, Hidalgo and Ahuazotepec, Puebla, both with 94 %. The best clones were: 19 and 20 (Ahuazotepec) and 75 (Agua Blanca, Hidalgo) with 100 % survival. A correlation was observed between vegetative phenology and presence of female strobili with 11 bioclimatic variables. It was concluded that the survival, phenology and production of female strobili of P. patula ramets are influenced by their origin. [ABSTRACT FROM AUTHOR]

In this paper were studied the physicochemical characteristics of organic waste generated in the municipality of Suchiapa, Chiapas, México. The objective was to characterize fruit and vegetable residues: pumpkin peel, tamarind peel, corn cob leaves and livestock fecal residues: cattle, sheep and poultry manure, to determine their optimal use in biogas and methane production. The parameters analyzed were humidity, ashes, pH, total solids (ST), total volatile solids (STV), carbon (C) and nitrogen (N), applying the methods of the Official Mexican Standards (NMXAA-016 to the NMX -AA-025). The results obtained from the calculation of STV, estimated a theoretical production of 850 L of methane/kg of STV through the use of pumpkin peel, being the best residue to guarantee biogas production. In this way, with the physicochemical characterization of the waste, it is possible to revalue their potential for the production of biogas. [ABSTRACT FROM AUTHOR]

Non-Steroidal Anti-Inflammatory Drugs are the cornerstone in the treatment of acute and chronic pain due to inflammation in musculoskeletal conditions. Even though adverse side-effects are associated, their use is common in the elderly patients. Our aim is to determine the prescription trend of NSAIDs, the evaluation for gastrointestinal (GI) and cardiovascular (CV) risks, and the level of agreement with prescription guidelines. We conducted an observation and descriptive study in a general hospital geriatrics consultation. From the 231 patients only 59 patients had a NSAIDs prescription. The most frequently prescribed was Acetaminophen, in 29(49.1%) patients, Celecoxib was prescribed in 11(18.6%) patients, Piroxicam in 5(8.4%) patients, Acetaminophen plus Celecoxib plus Omeprazole in 4 (6.7%), Acetaminophen plus Piroxicam in 2 (0.3%) patients, and Acetaminophen plus Diclofenac plus Celecoxib in 1 patient (1.6%). In the Framingham risk classification there were 160/231 (69.3%) patients in Very High Risk and 71/231 (30.7%) patients in High Risk. There were no patients in Low Risk. GI Risk: 79 patients (34.1%) had a peptic ulcer disease history. There were 55/231 (23.8%) in the High GI Risk classification, 102/231 (44.1%) in Intermediate GI Risk and 74/231 (32%) in the Low Risk. The level of agreement between the prescribed versus recommended NSAIDs according the CV and GI risks was measured with a contingence table and the kappa statistic of 0.37 p = 0.001. There is a low level of agreement between prescribed and recommended NSAID in elderly population. [ABSTRACT FROM AUTHOR]

Introduction This article shows how the current government of Jair Bolsonaro threatens the work of the press with attacks on journalists and media in Brazil that are critical of Bolsonaro's political management. Main goal This work of analysis and reflection aims to make visible the mechanisms of violence exerted on journalists through virtual harassment, disinformation practices and a hate speech against the politically correct promoted by the president. That is a part of the process classified as posttruth. Method Based on the analysis of the speech of Bolsonaro and other political figures, as well as offensive publications on social networks and judicial investigations, this article proofs the political strategy to promote disinformation. Results To achieve this objective, both the president and his followers affirm that the majority of the press is their enemy and they encourage delegitimization of the press. This strategy, lead by Bolsonaro, is looking to promote unilateral and partial communication with the population, to the detriment of professional informational criteria. The Supreme Court is processing various accusations against the president and his government for acts of disinformation and threats against journalist. Conclusions The Brazilian government ignores its constitutional responsibility to guarantee the freedom of the press and, in addition, exerts direct threats against journalists. This pressure sometimes translates into censorship or selfcensorship, as some professional's fear for their moral integrity and for their jobs. These practices hinder information work and threaten democracy. [ABSTRACT FROM AUTHOR]

A magnetohydrodynamic (MHD) generator is a device that generates electrical energy through the interaction between a conductive fluid and a magnetic field. This method of direct energy conversion allows the use of a renewable energy source such as solar energy and represents an alternative to tackle the greenhouse effect. This paper presents the development of an MHD solar generator, which is constituted by a solar thermal system and an MHD cell. The solar thermal system consists of a set of tubes with copper fins, connected in parallel and placed inside of a 1 m² panel. In which, an electrolytic mixture of H2O and NaCl at 20% vol. was introduced as a working fluid. In order to increase the kinetic energy of the fluid, the panel was exposed to solar radiation, where it reached temperatures above 373 K and pressures above 96 kPa. This solar thermal system operates in closed cycle conditions by including a check valve in its inlet-outlet junction; in this way, the fluid travels through the MHD generator. The MHD cell was composed of a block of polytetrafluoroethylene, two cylindrical stainless-steel electrodes, and four neodymium magnets. For simulation purposes, comsol multiphysics was used to reproduce the current density produced by the MHD solar generator. Pressure and temperature quantities obtained experimentally in the MHD cell were employed as boundary conditions. The experimental maximal current density obtained corresponds to 4.30 mA/m², and the comparison between theoretical and experimental results shows that the model fits fairly well. [ABSTRACT FROM AUTHOR]

Aim: This study was conducted to evaluate the physiological and biochemical effect in chickens of the Ross breed of a food enriched with agroindustrial waste. Materials and Methods: The food is one of the main components of the total cost for the production of chickens. Rations should be formulated to provide the correct balance of energy, protein, amino acids, minerals, vitamins and essential fatty acids, to allow optimal growth and performance. This study was intended to evaluate a natural feed for chicken, made from corn, yucca meal, eggshells, orange peel, soybean meal, salt and garlic, enriched with agroindustrial waste (molasses, milk whey and ferment of coffee). The weight gain was evaluated in broilers using a diet enriched with different agroindustrial wastes, with respect to a control food of the same composition but not containing residue. To develop the experiment 120 male Ross 308 chicks were used, these were evaluated for 6 weeks. Physicochemical test for the food and the agroindustrial waste were performed; moisture was determined; organic carbon, organic material and the ash, to characterize the agroindustrial wastes, the reducing sugars content using a spectrophotometer at 540 nm and proteins through the Kjeldahl method was evaluated. During the experiment, the weight gain of chickens and feed conversion was evaluated; the end of the experiment the weight of eviscerated channel relative weight breast, thighs, pancreas, and abdominal fat was determined, besides including blood chemistries as determination of cholesterol, triglycerides, and glucose. Finally, the microbiological analyzes to detect the presence of Escherichia coli in the cecum was determinate. Data were analyzed by InfoStat statistical program using the generalized linear model procedure. The statistical comparison was made by Tukey test at the 95% probability level. Results: After the evaluation, fed chickens with the treatments food + milk whey (FMW) and food + ferment of coffee (FFC) demonstrated increased from 1949 to 1892 g, respectively, to the 42 days of evaluation, showing the best treatment for weight gain. However, the FFC treatment showed the best feed conversion reaching values of 1.79 related to levels of blood glucose (249 mg/dl). Even so the eviscerated channel yields were higher for the treatment FFC reaching 1810.1 g unlike the treatment FMW which it reached a weight of 1718.2 g with increased formation of abdominal fat (7.4 g) unlike other treatments. From the results, it is concluded that food enriched with coffee ferment allows an increase in weight, better feed conversion in addition to high production of lean meat. Conclusion: It was shown that the best treatment was the food enriched with the ferment of coffee, due to increased intake and weight gain at the end of 42 days of the experiment. [ABSTRACT FROM AUTHOR]

In this work, a sulfated titanium dioxide (STi) catalyst obtained from a commercial TiO2 precursor was synthesized and characterized. The catalyst was sulfated by the simple impregnation method with H2SO4 and subsequently calcined at different temperatures. The synthesized catalyst was characterized by X-ray Diffraction (XRD), Energy-Dispersive Spectroscopy (EDS), and Scanning Electron Microscopy (SEM). The sulfated catalyst was thermally treated at different temperatures (100, 200, 400, and 600 °C) and evaluated in oleic acid esterification reactions by varying the concentration of the catalyst during the conversion of oleic acid to methyl oleate. The conversion was measured from the variation of the acid index (AI)° and free fatty acids (FFA) during the reaction. The STi catalyst obtained was compared with two homogeneous catalysts, H2SO4 and ferric sulfate [Fe2(SO4)3], evaluating the reaction time in the conversion, from which improvements in the reaction performance of the catalyst synthesized in this work were observed versus the two homogeneous catalysts mentioned earlier. Catalyst reuse cycles were also evaluated as well as their performance in the esterification of waste cooking oil. The best catalyst yields reached values close to 86% in a reaction time of 6 h. [ABSTRACT FROM AUTHOR]

Lithium-oxygen cells, known for their exceptional energy density, have complex reaction processes making a quantitative elucidation of the reaction mechanism, especially at the cathode quite difficult. Using density functional theory (DFT) combined with nudged elastic band (NEB) calculations, and cyclic voltammetry (CV) experiments in high donor number solvents, we developed a numerical computational model that elucidates the primary reaction pathway at the cathode. This study highlights two key reasons for the voltage gap between the charging and discharging phases: the shift in lithium superoxide's reaction voltage from lithium peroxide's thermodynamic equilibrium voltage, and the extra energy needed to electrolyze nucleated lithium peroxide. This study shows that by optimizing the high donor number solvent system and optimum battery design, up to 78.9 % of theoretical specific energy can be achievable, signaling significant prospects for advancing Li-O₂ battery technology. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present work is demonstrated that single-walled carbon nanotubes (SWCNTs) are excellent one-dimensional (1D) structures for the growth and stabilization of CdS nanoparticles (CdS NPs) in dispersions. For this, we have synthesized colloidal CdS NPs owning different diameters (from 2 to 5.5 nm). Then, the surface modification of NPs by using nonylphenol as capping agent was evaluated. The modification of CdS NPs resulted in a crystal rearrangement for all the NP sizes to NPs of approximately 2 nm of diameter showing an enhanced photoluminescence signal at 415 nm. Following the same experimental procedure, CdS NPs directly grown on SWCNTs (CdSNPs@SWCNTs) show absorption and photoluminescence properties similar to those of already passivated NPs with nonylphenol, in consequence the addition of a better capping agent did not affect the optical properties of as-synthesized CdSNPs@SWCNTs. Our experimental results demonstrate that SWCNTs are excellent 1D templates for the growth and stabilization of CdS NPs allowing to combine the optical tunable properties of NPs with the outstanding electronic properties of SWCNTs. This facile low cost methodology provides a successful strategy for the development of applications in a large range of fields including heterogeneous catalysis, optoelectronic and photoelectronic devices. [ABSTRACT FROM AUTHOR]

Two series of Cu/Co/Cr modified Fischer-Tropsch catalyst promoted with Zn or Mn and an alkaline metal (Me: Li, Na, K, Rb, Cs) were prepared by co-precipitation method and tested for high alcohol synthesis (HAS) at one hour on-stream and at two temperatures, 300 and 350 °C. The results indicate that the best selectivity toward high alcohols depends on temperature and catalysts composition and is obtained as follows: a) at 300 °C over catalysts without Zn and containing K, Na and Rb; b) at 350 °C over catalysts without Zn and containing K; c) at 350 °C over catalysts containing Zn as well as Li and Cs. Graphical Abstract: Two series of Cu/Co/Cr modified Fischer-Tropsch catalyst promoted with Zn or Mn and an alkaline metal (Me: Li, Na, K, Rb, Cs) were prepared by co-precipitation method and tested for HAS at one hour on-stream and at two temperatures, 300 and 350 °C. The results indicate that the higher HA production (i.e. normal and branched butanol) is obtained at 350 °C over catalysts promoted with Zn and all alkali metals, except for Li which shown its best performance at 300 °C.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The article presents a study on the carbometalation of alkenes, alkynes, and arenes. It discusses the activation process of the unactivated carbon-carbon (C-C) multiple bonds through complexation with a metal salt. It explains the carbometalation process using zinc, palladium, and gallium and how these metallic elements promote the addition of enolate- or malonate-type nucleophiles. It suggests that further studies must be developed for better understanding of the endothermic process.

Two series of sulfated zirconia catalysts promoted with Pt and Pt–Ni, respectively, were prepared and extruded with different amount of alumina binder (0, 20, 33, and 60 wt%). The catalytic activities of the two series of catalysts, SZPtA and SZNiPtA, were measured for n-pentane isomerization reaction. The reaction reaches its maximum conversion at 20 wt% of alumina for both catalyst series. Adding alumina beyond 20 wt% reduces the overall conversion and modifies the selectivity for both catalysts series from i-C4 towards i-C5 suggesting that the reaction mechanism changed from a monomolecular to a bimolecular one. However, only SZNiPtA catalysts maintain a higher catalytic activity at higher amounts of alumina. Such difference between the two catalyst series can be attributed to the combining effect of Ni and Pt promotion of the SZNiPtA catalysts and not to their acidic properties. [ABSTRACT FROM AUTHOR]

Sulfated mixed oxides, SO/Ni–Al–O and SO/Zr–Al–O were evaluated for double bond isomerization (DBI) of 1-hexene using helium and hydrogen as carrier gases. The increase of temperature from 100 to 200 °C seems to favor the deprotonation pathway and contribute to increase the 1-hexene conversion for both catalysts and without regard of the carrier gas. The results indicate that temperature it is the main factor that contributes to improve both conversion and selectivity towards ( cis + trans)-2-hexene, while the reductive atmosphere beneficiate only the SO/Ni–Al–O catalyst performance, as hydrogen prevents this catalyst from a fast deactivation. [ABSTRACT FROM AUTHOR]

The high-yielding and highly efficient stereoselective synthesis of enantiopure anti,antiand syn,antiacetylenic 2-amino-1,3-diol stereotriads from α-alkoxy-tert-butanesulfinylimines bearing a stereocenter α to the imino group is reported. The stereoselectivity of the reaction of these tert-butanesulfinyl (tBS)-imines with allenylzinc (±)-1was found to be controlled only by the configuration of the tBS group. An excellent kinetic resolution of the racemic allenylzinc species was observed, allowing a high stereocontrol no matter what the configuration or the protecting group of the α-alkoxy group. [ABSTRACT FROM AUTHOR]

Abstract: Organozinc reagents (organozinc halides, diorganozincs and mixed copper–zinc reagents) react with β-(allyloxy)-enoates via a radical–polar crossover process to afford substituted furans in one single synthetic step following a domino reaction involving Michael addition and carbocyclisation. Reversal of diastereoselectivity can be obtained varying the organometallic and/or the reaction conditions. [Copyright &y& Elsevier]

The carbometalation reaction of zinc enolates and related stabilised organometallics on unactivated double bonds has emerged over the past decade as a mechanistically interesting and synthetically useful reaction. This Perspective is devoted to these challenging and apparently contra-thermodynamic transformations, with a special focus on recent mechanistic considerations involving radical–polar crossover reaction pathways. [ABSTRACT FROM AUTHOR]

Abstract: A new addition reaction of a 3-alkoxy allenylzinc reagent to N-acyliminiums prepared in situ from imines and acid halides is reported. Unlike addition onto imines or nitrones that affords the trans adducts, acetylenic syn-1,2 amino ethers are yielded with good selectivities, thus providing a new entry to propargyl syn-1,2-aminoalcohol units. [Copyright &y& Elsevier]

Three Ni/ZrO2–SO/Al2O3 catalysts with different concentrations of platinum (0.2, 0.3 and 0.4 wt%) were prepare and tested for n-butane isomerization reaction at 338 K, in absence and in presence of hydrogen. The results shown that, at low temperature, platinum contributes to the olefin or butyl ion formation and the reaction follows a bimolecular pathway. However, when the reaction occurs in the presence of hydrogen, the formation of butyl ions is inhibited. The main feature of platinum addition is the stabilization of the catalytic activity, which is indicated by the slow deactivation constants compared to that of the unpromoted catalyst. [ABSTRACT FROM AUTHOR]

The formation of a hybrid metal-biopolymer material is described. The synthesis of this material consists of functionalizing the surface of gold nanoparticles through a series of steps that lead to epoxy-functionalized nano-particles. These are subsequently reacted with hydroxyl moieties of the α-D-glucopyranosyl groups of dextran. Subsequently, the dextran chains are carboxylated through treatment with bromoacetic acid. The resultant material combines the unique optical properties of gold nanoparticles with the versatility that carboxylated dextran offers for further functionalization with biomolecules. The interaction of this material with three proteins was then investigated through changes in the plasmon resonance properties of the gold nanoparticles. Concanavalin A, a lectin that binds glucose and mannose by means of specific molecular recognition, interacts readily with this material and such interaction is easily detected using optical absorption spectroscopy. Through reaction of the carboxyl groups with (+)-biotinyl-3,6,9,-trioxaundecanediamine, a material bearing biotin groups was obtained. This could interact with streptavidin or antibiotin by means of specific molecular recognition. Further confirmation of biospecific interactions was obtained with control experiments in which the binding sites were blocked through preincubation of the proteins with the corresponding ligand in solution. Binding of these proteins was concentration-dependent over a wide concentration range. This material provides a simple and convenient colorimetric method for biospecific interaction analysis. [ABSTRACT FROM AUTHOR]

Improvement of the sulfated zirconia catalysts (SZN) was studied by adding different amounts of alumina as follows: 17.5, 29.8, 45.9, and 56wt %. Even though, alumina, is expect to promote higher specific area and increase the amount of acid sites, stability of the zirconia tetragonal phase, the active zirconia phase of the SZN catalyst isisomerization reaction was obtained for catalysts containing between 17.5, and 29.8wt % of alumina, which reflects the promotional effect of alumina. On the contrary, a strong reduction of this reaction rate is observed when higher amounts of alumina are added to the catalyst, which indicates the dilution effect of alumina. [ABSTRACT FROM AUTHOR]

The pedagogy of the future will be an educational practice that breaks away from the reiterative process of ritual teaching, that only emphasizes the study of irrelevant problems that do not touch on reality from the perspective of transformational possibility. It is important to analyze of the diverse elements of a theoretical-methodological character that are present in a type of school culture that alienates the subject (student protagonist) from the school. Teaching constitutes a manner in which to communicate a culture that reproduces what is socially intrinsic from what is scholastically intrinsic. [ABSTRACT FROM AUTHOR]

Introduction: A positive academic performance is usually a sign of academic success and increases the chances that a student will succeed in his professional future. However, a student's academic performance can be greatly affected by socioeconomic factors such as climate and family socioeconomic status. In 2020, the COVID-19 pandemic caused the closure of several schools in Puerto Rico, which mostly affected low-income students who even depend on the lunches offered at school to be able to eat adequately and on the equipment available in schools to be able to perform their tasks. Objective: Therefore, this article aims to discuss the impact of the COVID-19 pandemic on the education and school performance of students with a low socioeconomic level in Puerto Rico. Method: This article analyzed research, professional opinions, and media coverage that addressed the phenomenon of the COVID-19 pandemic and the impact it had on Puerto Rican schoolchildren. This information was analyzed to contribute to Social Work, education, and social sciences in general. Results: It was documented that the COVID-19 pandemic exacerbated social inequality in students, including their access to technology and educational materials. Many Puerto Rican families did not have the necessary resources and materials to access the online platforms provided by the Department of Education. This situation increased the levels of inequality in the child population and limited the academic progress of children living in families with a low SES. In addition, the crisis generated by COVID-19 has caused the closure of countless schools to control the spread of the pandemic. The closure of schools prevented several children living in poverty from having access to a healthy diet. In this sense, school children and youth were at risk of food insecurity, increasing the probability that they also present low academic performance, as well as risks to their physical and mental health. Conclusions: The COVID-19 pandemic has increased the vulnerability of Puerto Rican families with a low socioeconomic level, negatively impacting the school performance of their students. It is extremely important to identify strategies to work on this problem from areas such as social work, education, and social policy to guarantee that the basic and educational needs of Puerto Rican students are satisfied. [ABSTRACT FROM AUTHOR]

Electron transport across the magnetic field in Hall effect thrusters is still an open question. Models have so far assumed 1/B2 or 1/B scaling laws for the “anomalous” electron mobility, adjusted to reproduce the integrated performance parameters of the thruster. We show that models based on such mobility laws predict very different ion velocity distribution functions (IVDF) than measured by laser induced fluorescence (LIF). A fixed spatial mobility profile, obtained by analysis of improved LIF measurements, leads to much better model predictions of thruster performance and IVDF than 1/B2 or 1/B mobility laws for discharge voltages in the 500–700 V range. [ABSTRACT FROM AUTHOR]

Gold nanoparticles linked to linear carboxylated dextran chains were attached to 3-aminopropyltriethoxysilane-functionalized glass surfaces. This method provides novel hybrid nanostructures on a surface with the unique optical properties of gold nanoparticles. The particles attached to the surface retain the capability to aggregate and disaggregate in response to their environment. This procedure presents an alternative method to the immobilization of gold nanoparticles onto planar substrates. Compared to gold nanoparticle monolayers, larger particle surface densities were obtained. Exposure to hydrophobic environments changes the conformation of the hydrophilic dextran chains, causing the gold nanoparticles to aggregate and inducing changes in the absorption spectrum such as red-shifting and broadening of the plasmon absorption peaks. These changes, characteristic of particle aggregation, are reversible. When the substrates are dried and then immersed in an aqueous environment, these changes can be visually observed in a reversible fashion and the sample changes color from the red color of colloidal gold to a bluish-purple color of aggregated nanoparticles. Surface-bound nanoparticles that retain their mobility when attached to a surface by means of a flexible polymer chain could expand the use of aggregation-based assays to solid substrates. [ABSTRACT FROM AUTHOR]

The success of mRNA vaccines against SARS-CoV-2 has prompted interest in mRNA-based pharmaceuticals due to their rapid production, adaptability, and safety. Despite these advantages, the inherent instability of mRNA and its rapid degradation in vivo underscores the need for an encapsulation system for the administration and delivery of RNA-based therapeutics. Lipid nanoparticles (LNPs) have proven the most robust and safest option for in vivo applications. However, the mid- to long-term storage of mRNA-LNPs still requires sub-zero temperatures along the entire chain of supply, highlighting the need to develop alternatives to improve mRNA vaccine stability under non-freezing conditions to facilitate logistics and distribution. Lyophilization presents itself as an effective alternative to prolong the shelf life of mRNA vaccines under refrigeration conditions, although a complex optimization of the process parameters is needed to maintain the integrity of the mRNA-LNPs. Recent studies have demonstrated the feasibility of freeze-drying LNPs, showing that lyophilized mRNA-LNPs retain activity and stability. However, long-term functional data remain limited. Herein, we focus on obtaining an optimized lyophilizable mRNA-LNP formulation through the careful selection of an optimal buffer and cryoprotectant and by tuning freeze-drying parameters. The results demonstrate that our optimized lyophilization process maintains LNP characteristics and functionality for over a year at refrigerated temperatures, offering a viable solution to the logistical hurdles of mRNA vaccine distribution. [ABSTRACT FROM AUTHOR]

While the adverse effects of housing insecurity on mental health are known, much less is known about the modifiers underlying these effects. The aim of this study was to analyze the mental health of people with housing insecurity by housing tenure and considering the coexistence of other life insecurities (energy poverty and food insecurity). We conducted a cross-sectional study through a survey performed in all people attending the Platform for People Affected by Mortgages or the Alliance against Energy Poverty of Barcelona for the first time between June 2017 and December 2019 and who reported housing insecurity. The dependent variables were the risk of poor mental health, self-reported anxiety and/or depression, and the use of psychotropic drugs. We fitted age-adjusted robust Poisson regression models for each dependent variable and estimated adjusted prevalence ratios (aPR). The study included 256 women and 104 men. The prevalence of poor mental health was 89% in women and 85.3% in men, which was much higher than that in the general population of Barcelona (19.5% and 14.5%, respectively). Among women, mental health was worse in those living in a squat (aPR 1.16; 95% CI: 1.02–1.31) and in those with food insecurity (aPR 1.11; 95% CI: 1.01–1.21). The number of coexisting insecurities showed a gradient effect (3 insecurities: aPR 1.21; 95% CI: 1.01–1.45). Among men, the results showed no clear pattern. Poor mental health was highly prevalent in people with housing insecurity and was exacerbated by the coexistence of life insecurities. Public policymakers should consider the complexity of persons with housing insecurity. [ABSTRACT FROM AUTHOR]

Este trabajo tuvo como objetivo determinar la presencia e identificar las especies de bacterias altamente eficientes en la solubilizacion de fósforo en suelos del Valle del Sinú, Córdoba. Para ello, se tomaron muestras de suelo en 5 municipios del departamento: Montería, Cerete, Lorica, San Pelayo y Tierralta en cultivos comerciales de algodón, arroz o maíz. Las muestras de suelo se diluyeron a 1x10-6 en solución salina. Se tomo de cada dilución una alícuota de 100 μl y se sembró en medio selectivo con fosfato tricálcico como fuente de fósforo (NBRIP). Los aislamientos fueron resembrados en medio agar nutriente donde se les determinaron las características morfológicas de las colonias, composición de la membrana citoplasmática mediante tinción de gram y prueba de Ryu. La eficiencia solubilizadora de fosforo se evaluó utilizando el método de índice de solubilización (IS) propuesto por Kumar y Narula (1999) en medio NBRIP. Las bacterias eficientes (IS ≥ 3mm) se amplificaron utilizando PCR con el primer universal 16S (27 forward y 1492 reverse), la secuenciación de los amplicones, como del control positivo (C+) se logró con electroforesis capilar y se analizaron mediante el alineamiento de los amplicones en la base de datos del GenBank del con la herramienta BLAST nucleotide del NCBI. El formato de los archivos de las secuencias (.AB1) fue leído con la herramienta bioinformática 4Peaks y se construyó un dendograma con todas las secuencias a través de Blast Tree View. Se aislaron 90 cepas con capacidad de solubilizar fósforo (32 en algodón, 32 en maíz y 27 en arroz). Veintidós de las 90 tuvieron un IS ≥ a 3mm (10 asociadas al cultivo de algodón, 3 de arroz y 9 de maíz). Las especies bacterianas identificadas por alineamiento fueron Achromobacter marplatensis, Klebsiella pneumoniae, Pseudomonas aeruginosa, P. luteola, P. nitroreducens, P. protegens, P. yamanorum y el género Enterobacter sp. Los resultados demuestran que los suelos productores de algodón, arroz y maíz en el departamento de Córdoba presentan bacterias altamente eficientes en la solubilización de fósforo [ABSTRACT FROM AUTHOR]

Este trabajo tuvo como objetivo determinar la presencia e identificar las especies de bacterias altamente eficientes en la solubilizacion de fósforo en suelos del Valle del Sinú, Córdoba. Para ello, se tomaron muestras de suelo en 5 municipios del departamento: Montería, Cerete, Lorica, San Pelayo y Tierralta en cultivos comerciales de algodón, arroz o maíz. Las muestras de suelo se diluyeron a 1x10-6 en solución salina. Se tomo de cada dilución una alícuota de 100 μl y se sembró en medio selectivo con fosfato tricálcico como fuente de fósforo (NBRIP). Los aislamientos fueron resembrados en medio agar nutriente donde se les determinaron las características morfológicas de las colonias, composición de la membrana citoplasmática mediante tinción de gram y prueba de Ryu. La eficiencia solubilizadora de fosforo se evaluó utilizando el método de índice de solubilización (IS) propuesto por Kumar y Narula (1999) en medio NBRIP. Las bacterias eficientes (IS ≥ 3mm) se amplificaron utilizando PCR con el primer universal 16S (27 forward y 1492 reverse), la secuenciación de los amplicones, como del control positivo (C+) se logró con electroforesis capilar y se analizaron mediante el alineamiento de los amplicones en la base de datos del GenBank del con la herramienta BLAST nucleotide del NCBI. El formato de los archivos de las secuencias (.AB1) fue leído con la herramienta bioinformática 4Peaks y se construyó un dendograma con todas las secuencias a través de Blast Tree View. Se aislaron 90 cepas con capacidad de solubilizar fósforo (32 en algodón, 32 en maíz y 27 en arroz). Veintidós de las 90 tuvieron un IS ≥ a 3mm (10 asociadas al cultivo de algodón, 3 de arroz y 9 de maíz). Las especies bacterianas identificadas por alineamiento fueron Achromobacter marplatensis, Klebsiella pneumoniae, Pseudomonas aeruginosa, P. luteola, P. nitroreducens, P. protegens, P. yamanorum y el género Enterobacter sp. Los resultados demuestran que los suelos productores de algodón, arroz y maíz en el departamento de Córdoba presentan bacterias altamente eficientes en la solubilización de fósforo. [ABSTRACT FROM AUTHOR]

Carbon Nanotubes (CNTs) are considered alternative materials for the design of advanced drug and gene delivery vectors. However, the mechanism responsible for the cellular membrane intake of CNTs is not well understood. In the present study, we show how multi-walled carbon nanotubes (MWCNTs) owning different surface properties, interact with giant unilamellar vesicles (GUVs), a simple model system for cellular membranes. In particular, we want to address the hydrophilic/hydrophobic interactions between MWCNTs and lipid membranes and the subsequent mechanical properties changes of the systems. In order to elucidate this interaction, we made the following chemical modifications on MWCNTs: oxidized MWCNTs (ox-MWCNTs) displaying reduced hydrophobic surface character, pristine MWCNTs (p-MWCNTs), and alkyl functionalized MWCNTs (alk-MWCNTs) exhibiting enhanced hydrophobic surface properties, were put in contact with GUVs and observed by confocal microscopy. Our observations revealed that the interaction between the CNTs and GUVs depends on the type of chemical functionalization: ox-MWCNTs remain at the membrane interacting with the polar head of the phospholipids, p-MWCNTs internalize GUVs spontaneously, and alk-MWCNTs persist inside the membrane. The mechanical properties of MWCNTs@GUVs systems were measured using the electrodeformation method, which shows an increased bending stiffness (κ) of the GUVs as MWCNTs concentration increases. High concentrations of p-MWCNTs and alk-MWCNTs induced vesicle adhesion; p-MWCNTs produced a considerable reduction in the average size of the GUVs, while alk-MWCNTs form complex stable structures inside the membrane. The statistical analyses of the experimental results are compared with available computer simulations. The picture emerging from our results is that the interaction between GUVs and MWCNTs is due mainly to hydrophobicity. [ABSTRACT FROM AUTHOR]

A semiempirical time-dependent thermal model of Hall effect thrusters was developed to compute evolution of the thruster channel wall temperature during a transient regime. The model accounts for heat conduction through dielectric walls and radiative transfer as the channel is considered as a thermal enclosure. The graybody view factors are experimentally determined during the cooling period that follows a power shutdown. The model permits the assessment of the amount of power delivered to walls by fitting calculated temperature profiles to experimental profiles obtained by means of calibrated infrared imaging. Plasma-surface interactions are examined in this contribution for three types of thrusters, namely, SPT100-ML, PPS®1350-G, and the 5-kW-class PPSX000-ML. The electrical input power range that is probed stretches out from 500 W to 5 kW. The energy flux passed to the discharge chamber dielectric walls varies between 0.1 and 2 W/cm2. The overall amount of power delivered to the external and internal walls is found to vary linearly with the applied power. It is in favor of an energy loss mechanism driven by ion bombardment. A departure from the linear trend is observed at high discharge voltage. Production of multiply charged ion species could be an explanation. The impact of thruster design and wall material on power losses inside the thruster channel is also investigated from both a technological and a physics standpoint. [ABSTRACT FROM AUTHOR]

Angioplasmocellular hyperplasia is an uncommon dermatosis of which less than 20 cases have been reported in the literature and whose etiopathogenesis is unknown. It presents in the head, trunk and extremities as a neoformation of vascular appearance. The diagnosis is made by the histopathological study finding proliferation of capillary vessels surrounded by plasmocitary infiltrate. [ABSTRACT FROM AUTHOR]

Perioral granulomatous dermatitis predominates in middle-aged women and may also occur at an extrafacial level. The vast majority of patients have a history of having received topical steroids for a long time. Clinically it presents with micronodules, papules and pustules that can be pruritic and usually of chronic evolution. The histopathological study does not present pathognomonic characteristics of the disease, but it can guide the diagnosis by finding the formation of tuberculoid granulomas. The main treatment is to stop the use of topical steroids. [ABSTRACT FROM AUTHOR]

Hall effect thrusters (HETs) are one of the developed electric devices for space propulsion since the late 1960s. Great technological and scientific advances in this domain have been achieved. Nevertheless, the physics involved is not completely mastered. One of the unknowns is the cross-field electron mobility in the E × B thruster configuration: Classical electron mobility is not sufficient to explain thruster general performance. One of the most convincing theories is the presence of an azimuthal turbulence that is responsible for the so-called "anomalous transport." The aim of this paper is to shed light on the "anomalous transport" through a study of electron trajectories in a HET. [ABSTRACT FROM AUTHOR]

The main of this study was to evaluate the effect of supplementation of tropical tree foliage in ruminant diets on the in vitro fermentation, bacterial population, volatile fatty acids (VFAs), and enteric CH4 production. Seven experimental diets were evaluated: a control treatment of Pennisetum purpureum (T7) and six treatments of P. purpureum supplemented (30%) with the foliage of Neomillspaughia emargiata (T1), Tabernaemontana amygdalifolia (T2), Caesalpinia gaumeri (T3), Piscidia piscipula (T4), Leucaena leucocephala (T5), and Havardia albicans (T6). The T2, T7, and T5 treatments had the highest (p < 0.05) digestibility of dry matter. Overall, supplementation increased (p < 0.05) the concentrations of propionic and butyric acid and decreased acetic acid. Methanogenic bacteria decreased (p < 0.05) in T1, T2, T5, and T6. Ruminococcus albus decreased in T1, T2, T3, and T5 and Selenomonas ruminiantum increased in T3. Fibrobacter succinogenes increased, except in T5. Methane production decreased (p < 0.05) in T1, T4, T5, and T6. The supplementation with Leucaena leucocephala, Tabernaemontana amygdalifolia, Neomillspaughia emargiata, Piscidia piscipula, Havardia albicans, and Caesalpinia gaumeri is a potential alternative nutritional strategy for ruminants that results in positive changes in VFAs profile, a decrease on CH4 production and methanogenic bacteria, and changes on fibrolytic and non-fibrolytic bacteria composition. Tropical tree foliage supplementation increased propionic and butyric acid and decreased acetic acid concentrations. Fibrolytic, non-fibrolytic, and Methanogenic bacteria were selectively modulated with the supplementation of tropical tree foliage. The enteric methane (CH4) production decreased with the supplementation of tree foliage. The supplementation of Tabernaemontana amygdalifolia and Leucaena leucocephala had the highest digestibility and is a potential alternative nutritional strategy for ruminants. [ABSTRACT FROM AUTHOR]

Poly (ethylene glycol)-co-(-Lactic acid) diacrylate (PEG-PLLA-DA) copolymers have been extensively investigated for a number of applications in medicine. PEG-PLLA-DA is biodegradable and the human body can process its degradation products. In this study, we describe the autofluorescence of PEG-PLLA-DA copolymers and compared it to the fluorescence of poly(ethylene glycol) diacrylate (PEG-DA) and the precursor molecules used for their synthesis. In addition, we examined the influence of pH on the fluorescence spectra. We found that PEG-PLLA-DA exhibits higher fluorescence than PEG-DA and all reagents involved in the synthesis of PEG-PLLA-DA. The fluorescence of PEG-PLLA-DA was affected by pH with fluorescence decreasing at high pH values. At high pH, PEG-PLLA-DA could not polymerize into hydrogels and exhibited a dramatic decrease in autofluorescence, suggesting that hydrolysis of the ester bond affected its autofluorescence. At low pH, PEG-PLLA-DA exhibited higher fluorescence and it was able to form crosslinked hydrogels. The autofluorescence of PEG-PLLA-DA could be exploited to monitor polymer degradation and material structure without the need to introduce exogenous fluorescent probes. The origin of fluorescence is not clear at this point in time but it appears to result from a synergetic effect of both lactate units and diacrylate groups in the PEG-PLLA-DA backbone. The observed autofluorescence of PEG-PLLA-DA persists after reaction of the acrylate groups in the polymerization reaction. This autofluorescence is advantageous because it could assist in the study of polymers used for drug delivery and tissue engineering applications. [ABSTRACT FROM AUTHOR]

The short and efficient asymmetric synthesis of (−)-1-hydroxyquinolizidinone was achieved in seven steps and 25.2% overall yield from readily available 5-chloropentanal. It is a key intermediate in the formal syntheses of (−)-homopumilotoxin 223G and (−)-epiquinamide. [ABSTRACT FROM AUTHOR]

Age-related eye diseases, including dry eye, glaucoma, age-related macular degeneration, and diabetic retinopathy, represent a major global health issue based on their increasing prevalence and disabling action. Unraveling the molecular mechanisms underlying these diseases will provide novel opportunities to reduce the burden of age-related eye diseases and improve eye health, contributing to sustainable development goals achievement. The impairment of neutrophil extracellular traps formation/degradation processes seems to be one of these mechanisms. These traps formed by a meshwork of DNA and neutrophil cytosolic granule proteins may exacerbate the inflammatory response promoting chronic inflammation, a pivotal cause of age-related diseases. In this review, we describe current findings that suggest the role of neutrophils and their traps in the pathogenesis of the above-mentioned age-related eye diseases. Furthermore, we discuss why these cells and their constituents could be biomarkers and therapeutic targets for dry eye, glaucoma, age-related macular degeneration, and diabetic retinopathy. We also examine the therapeutic potential of some neutrophil function modulators and provide several recommendations for future research in age-related eye diseases. • Neutrophils are pathogenic mediators shared by age-related eye diseases. • Neutrophil constituents are rising biomarkers of age-related eye diseases. • Lipocalin 2 is a hopeful marker/therapeutic target of age-related retinal diseases • Neutrophil receptors are emerging therapeutic targets of age-related eye diseases. [ABSTRACT FROM AUTHOR]

Objective. To evaluate the nutrient profile and marketing techniques (MT) of processed wheat and maize foods (PWMF) sold in food retail outlets of Mexico City. Materials and methods. We collected information on nutrient content and MT for PWMF across twelve food categories from 58 retail outlets in high and low income areas of Mexico City. Results. Roughly 8.5% and 10.7% of PWMF, in low and high income areas were healthy, respectively. The =12% of PWMF were healthy, except for flours (~33%) and pastas (=95%). Across both income areas, 28.3%-31.9% of WMPF employed characters, 46.5%-50.1% promotions and 38.2%- 41.3% claims. A significant association (p<0.001) was found between the use of MT and unhealthy PWMF in both areas. Conclusion. The majority of PWMF available in the food retail sector were considered unhealthy, which were being more offered in low income areas. Across income areas, the majority of unhealthy WMPF employed MT to encourage consumption. [ABSTRACT FROM AUTHOR]

ZnO/MWCNT composite thin films were prepared on glass substrates by spray pyrolysis, and their structural and optical behavior were investigated. X-ray diffraction analysis revealed the films hexagonal wurtzite phase with a preferred (002) growth orientation. Photoluminescence spectra of the ZnO film showed two main bands, a UV emission band at 377 nm (3.28 eV) and a broad blue-yellow band at 439–546 nm with a band at 503 nm. Optical transmittance of 80–85% in the visible range was observed in all the films. In the I–V curves, conductivity was improved when incorporating the MWCNT into the zinc oxide. ZnO/MWCNT, at a value of 2 V and irradiated with visible light presented an increased current from 0.6 to 3.2 nA, and a similar pattern was observed when impinging UV light. Film thickness was measured by profilometry, obtaining thicknesses in the range from 143 to 257 nm. [ABSTRACT FROM AUTHOR]

The article presents a new methodology that employs 3D printing technology to generate a microporous composite material of polylactic acid, sodium alginate and hydroxyapatite, whose microstructure is designed by means of the 3D numerical solution from a mathematical model. This model represents the spatio-temporal dynamics of the interaction between osteoblasts and osteoclasts in the bone remodeling. The microporosity of composite material mimics the structure of human trabecular bone. This material has density with microporosity pretty close to the one that is exhibited by the natural bone tissue. Close relationship between the material processing and its elasticity module is observed. When subjecting this composite material to a simulated body fluid treatment, the mechanical resistance to compression is increased due to induced mineralization of hydroxyapatite crystals on its surface. The methodology shows potential to generate structures that allow the control of the composite material properties. The material presents a microporosity that has morphological and chemical properties suitable for future applications in tissue engineering as bone scaffold. [ABSTRACT FROM AUTHOR]

Abstract Orexins (OXs) system has been suggested to play a key role in regulate processes related to arousal, including anxious behaviors. However, until now, the contribution of OXs in anxiogenic-like effects has not been completely clear, particularly in rats, whose results are not yet conclusive in behavioral-tests such as elevated-plus-maze test (EPM-test). The goal of this study was to explore the anxiogenic-like effect induced by orexin-A (OX-A) using two different paradigms; the EPM-test and simultaneously a quantitative index in vivo , the cortical-electroencephalographic-(EEG)-record. This index proposes that a low-frequency domain EEG, particularly 0.5–5-Hz (delta and low portion of theta-waves), is a key indicator to evaluate anxiety levels. We also explored whether the anxious effect of OX-A could be altered by an antagonist of dopamine-D2-receptor (D 2 R) sulpiride (SUL). Our results showed that intracerebroventricular (i.c.v.) injection of a low dose of OX-A (140 pmol) did not increase anxiety levels in rats. On the other hand, cortical-EEG-activity showed only a decrease in delta-spectral-power but no changes in theta-potency. These data suggest that the reduction in delta-power induced by OX-A only keeps the animals awake and alert without changes in anxiety levels. [ABSTRACT FROM AUTHOR]

Se evaluaron mediante la técnica de producción de gas in vitro, fuentes energéticas locales (melaza, Zea mays L. y Musa paradisiaca L.) sobre la fermentación ruminal y producción de metano de diversos forrajes usados en un sistema silvopastoril con Panicum maximum cv. Tanzania, Gliricidia sepium (Jacq.) y Leucaena leucocephala cv. Cunningham, con ovinos. Se usaron cinco borregos Pelibuey x Katahdin 40 ± 3 (μ±DE) kg como donantes de líquido ruminal. Se analizaron cinco tratamientos (dietas) con diferentes mezclas de follaje de arbóreas y fuentes energéticas en un diseño experimental completamente al azar. M. paradisiaca y Z. mays presentaron los mayores registros de volumen (V) máximo en producción de gas (544 y 467 ml/g-1 MS, respectivamente) (P≤0.05). El follaje de G. sepium y L. leucocephala tuvieron los menores valores de V (253 y 180 ml/g-1 MS, respectivamente) (P≤0.05). La dieta D4 GMP (48 % P. maximum, 30 % G. sepium, 7 % Zea mays, 15 % M. paradisiaca) registro el mayor valor de V. No hubo diferencia (P>0.05) en la producción de metano en las dietas usadas, teniendo un rango de 6.31 a 9.60 de LCH4/kg MSDIG. Se generó un índice de emisión potencial de gases fermentables (IPEGF), el cual sugirió que dietas con carbohidratos de lenta fermentación, contribuyen a un índice más alto de emisión de gases. Por su mejoramiento en la calidad de las dietas y en contribuir en una baja de emisiones de CH4, se sugiere el manejo de arbóreas forrajeras como G. sepium y L. leucocephala, incorporando fuentes energéticas locales. [ABSTRACT FROM AUTHOR]

4-Aminopropargylic acetates afford 4-amino-1-allenylsilanes upon reaction with the lithium (triorganosilyl)zincate (PhMe2Si)3ZnLi. The reaction is both stereoselective and stereospecific and proceeds through syn-silylzincation of the carbon-carbon triple bond followed by subsequent anti-ß-elimination of the acetate group. [ABSTRACT FROM AUTHOR]

The ring-opening of N-tert-butanesulfinylethynylaziridines with lithium tris(dimethylphenylsilyl)zincate is reported. The reaction is demonstrated to be both stereoselective and stereospecific and to proceed through an anti-SN2′ process. Further deprotection of the nitrogen atom under mild conditions allows access to 4-amino-1-(dimethylphenylsilyl)allenes with high yields and levels of stereoselectivity. [ABSTRACT FROM AUTHOR]

Purpose: To control degradation and protein release using thermo-responsive hydrogels for localized delivery of anti-angiogenic proteins. Methods: Thermo-responsive hydrogels derived from N-isopropylacrylamide (NIPAAm) and crosslinked with poly(ethylene glycol)-co-(L-lactic acid) diacrylate (Acry-PLLA- b-PEG- b-PLLA-Acry) were synthesized via free radical polymerization in the presence of glutathione, a chain transfer agent (CTA) added to modulate their degradation and release properties. Immunoglobulin G (IgG) and the recombinant proteins Avastin® and Lucentis® were encapsulated in these hydrogels and their release was studied. Results: The encapsulation efficiency of IgG was high (75-87%) and decreased with CTA concentration. The transition temperature of these hydrogels was below physiological temperature, which is important for minimally invasive therapies involving these materials. The toxicity from unreacted monomers and free radical initiators was eliminated with a minimum of three buffer extractions. Addition of CTA accelerated degradation and resulted in complete protein release. Glutathione caused the degradation products to become solubilized even at 37°C. Hydrogels prepared without glutathione did not disintegrate nor released protein completely after 3 weeks at 37°C. PEGylation of IgG postponed the burst release effect. Avastin® and Lucentis® released from degraded hydrogels retained their biological activity. Conclusions: These systems offer a promising platform for the localized delivery of proteins. [ABSTRACT FROM AUTHOR]

The rearrangement of acetylenic epoxides mediated by low-valence organotitanium and organozirconium reagents is reported to give conjugated enynes. Moderate to good yields and high selectivities are obtained when using the organozirconium(II) Negishi reagent in toluene at 20 °C; whereas only poor yields and low selectivities are achieved with the organotitanium(II) Sato reagent. The process is stereospecific and involves formation of titana- and zirconacyclopropenes by oxidative insertion of the lowvalence titanium and zirconium reagents into the carbon–carbon triple bond of the acetylenic epoxides. These metallacyclopropenes then rearrange to afford stereodefined propargylmetals through the epoxide ring-opening. Conjugated enynes are finally produced by β-elimination of metal oxide. [ABSTRACT FROM AUTHOR]

Reaction of dialkylzincs with lithiated acetylenic epoxides is described to give zincates that undergo a 1,2-metallate rearrangement by an anti-SN2' pathway. This rearrangement occurs with the transfer of an alkyl or a silyl group affording allenylzinc intermediates. Allenic and/or homopropargylic alcohols are obtained upon hydrolysis. Quenching the reaction mixture with aldehydes or ketones is shown to give access to 2-alkynyl-1,3-diols in a stereoselective manner. [ABSTRACT FROM AUTHOR]