Synthesis and Characterization of Nanocomposite Hydrogels Based on Poly(Sodium 4-Styrene Sulfonate) under Very-High Concentration Regimen of Clays (Bentonite and Kaolinite).

The aim of this work was to synthesize and study the functional properties of polymer-clay nanocomposite (PCNCs) based on poly(sodium 4-styrene sulfonate) (NaPSS) and two types of clay in the dispersed phase: bentonite and kaolinite, in order to advance in the development of new geomimetic materials for agricultural and environmental applications. In this study, the effect of adding high concentrations of clay (10-20 wt. %) on the structural and functional properties of a polymer-clay nanocomposite was evaluated. The characterization by infrared spectroscopy made it possible to show that the PCNCs had a hybrid nature structure through the identification of typical vibration bands of the clay matrix and NaPSS. In addition, scanning electron microscopy allowed us to verify its hybrid composition and an amorphous particle-like morphology. The thermal characterization showed degradation temperatures higher than ~300 °C with Tg values higher than 100 °C and variables depending on the clay contents. In addition, the PCNCs showed a high water-retention capacity (>2900%) and cation exchange capacity (>112 meq/100 g). Finally, the results demonstrated the ability of geomimetic conditioners to mimic the structure and functional properties of soils, suggesting their potential application in improving soil quality for plant growth.

Nanocarrier of α-Tocopheryl Succinate Based on a Copolymer Derivative of (4,7-dichloroquinolin-2-yl)methanol and Its Cytotoxicity against a Breast Cancer Cell Line.

In order to improve the water solubility and, therefore, bioavailability and therapeutic activity of anticancer hydrophobic drug α-tocopherol succinate (α-TOS), in this work, copolymers were synthesized via free radicals from QMES (1-[4,7-dichloroquinolin-2-ylmethyl]-4-methacryloyloxyethyl succinate) and VP (N-vinyl-2-pirrolidone) using different molar ratios, and were used to nanoencapsulate and deliver α-TOS into cancer cells MCF-7. QMES monomer was chosen because the QMES pendant group in the polymer tends to hydrolyze to form free 4,7-dichloro-2-quinolinemethanol (QOH), which also, like α-TOS, exhibit anti-proliferative effects on cancerous cells. From the QMES-VP 30:70 (QMES-30) and 40:60 (QMES-40) copolymers obtained, it was possible to prepare aqueous suspensions of empty nanoparticles (NPs) loaded with α-TOS by nanoprecipitation. The diameter and encapsulation efficiency (%EE) of the QMES-30 NPs loaded with α-TOS were 128.6 nm and 52%; while for the QMES-40 NPs loaded with α-TOS, they were 148.8 nm and 65%. The results of the AlamarBlue assay at 72 h of treatment show that empty QMES-30 NPs (without α-TOS) produced a marked cytotoxic effect on MCF-7 breast cancer cells, corresponding to an IC50 value of 0.043 mg mL-1, and importantly, they did not exhibit cytotoxicity against healthy HUVEC cells. Furthermore, NP-QMES-40 loaded with α-TOS were cytotoxic with an IC50 value of 0.076 mg mL-1, demonstrating a progressive release of α-TOS; however, the latter nanoparticles were also cytotoxic to healthy cells in the range of the assayed concentrations. These results contribute to the search for a new polymeric nanocarrier of QOH, α-TOS or other hydrophobic drugs for the treatment of cancer or others diseases treatable with these drugs.

Comparative Study of the Removal Efficiency of Nalidixic Acid by Poly[(4-vinylbenzyl)trimethylammonium Chloride] and N-Alkylated Chitosan through the Ultrafiltration Technique and Its Approximation through Theoretical Calculations.

Emerging antibiotic contaminants in water is a global problem because bacterial strains resistant to these antibiotics arise, risking human health. This study describes the use of poly[(4-vinylbenzyl) trimethylammonium chloride] and N-alkylated chitosan, two cationic polymers with different natures and structures to remove nalidixic acid. Both contain ammonium salt as a functional group. One of them is a synthetic polymer, and the other is a modified artificial polymer. The removal of the antibiotic was investigated under various experimental conditions (pH, ionic strength, and antibiotic concentration) using the technique of liquid-phase polymer-based retention (LPR). In addition, a stochastic algorithm provided by Fukui's functions is used. It was shown that alkylated N-chitosan presents 65.0% removal at pH 7, while poly[(4-vinylbenzyl)trimethylammonium chloride] removes 75.0% at pH 9. The interaction mechanisms that predominate the removal processes are electrostatic interactions, π-π interactions, and hydrogen bonding. The polymers reached maximum retention capacities of 1605 mg g-1 for poly[(4-vinylbenzyl) trimethylammonium chloride] and 561 mg g-1 of antibiotic per gram for alkylated poly(N-chitosan). In conclusion, the presence of aromatic groups improves the capacity and polymer-antibiotic interactions.

Bio-Based Polymeric Membranes: Development and Environmental Applications.

Nowadays, membrane technology is an efficient process for separating compounds with minimal structural abrasion; however, the manufacture of membranes still has several drawbacks to being profitable and competitive commercially under an environmentally friendly approach. In this sense, this review focuses on bio-based polymeric membranes as an alternative to solve the environmental concern caused by the use of polymeric materials of fossil origin. The fabrication of bio-based polymeric membranes is explained through a general description of elements such as the selection of bio-based polymers, the preparation methods, the usefulness of additives, the search for green solvents, and the characterization of the membranes. The advantages and disadvantages of bio-based polymeric membranes are discussed, and the application of bio-based membranes to recover organic and inorganic contaminants is also discussed.

Electrochemistry Study of Bio-Based Composite Biopolymer Electrolyte-Starch/Cardol.

The environmental problems generated by pollution due to polymers of petrochemical origin have led to the search for eco-friendly alternatives such as the development of biopolymers or bio-based polymers. The aim of this work was to evaluate the electrochemical behavior of a biopolymer composite made from cassava starch and cardol extracted from cashew nut shell liquid. The biopolymers were prepared using the thermochemical method, varying the synthesis pH and the cardol amounts. The biopolymers were synthesized in the form of films and characterized by cyclic voltamperometry and electrochemical impedance spectroscopy. The biopolymers showed a rich electroactivity, with three oxidation-reduction processes evidenced in the voltamperograms. On the other hand, the equivalent circuit corresponding to the impedance behavior of biopolymers integrated the processes of electron transfer resistance, electric double layer, redox reaction process, and resistance of the biopolymeric matrix. The results allowed us to conclude that the cardol content and the synthesis pH were factors that affect the electrochemical behavior of biopolymer composite films. Electrochemical processes in biopolymers were reversible and involved two-electron transfer and were diffusion-controlled processes.

Multiple surface interaction mechanisms direct the anchoring, co-aggregation and formation of dual-species biofilm between Candida albicans and Helicobacter pylori.

Introduction: Polymicrobial biofilms have a significant impact on pathogenesis of infectious microorganisms. Many human diseases are affected by colonization of multi-species communities affecting negatively the treatments and increase the risks for the health. In particular, in the epithelium of the stomach co-existence between C. albicans and H. pylori has been described, which has been associated to a synergistic effect on ulcer pathogenesis. Objective: The objective of this work was to advance in the understanding of surface interaction between H. pylori and C. albicans for the formation of polymicrobial biofilms. Methods: Studies of microbial surfaces both bacterium, yeast and co-cultures of them were carried out by infrared spectroscopy, deconvolution analysis, transmission and scanning electron microscopies, and optic microscopy. Additional methods were used to contrast the results as dynamic light scattering, contact angle, agarose gel electrophoresis and gene amplification. Results: Several surface interaction mechanisms promote the anchoring of H. pylori on C. albicans, cell co-aggregation, and polymicrobial biofilm formation, main identified interactions were: (i) hydrophobic interactions between non-polar peptide chains and lipid structures, characterized by θw among 84.9 ± 1.6 (γ = 22.78 mJ/m2 with 95.3 of dispersive contribution) and 76.6 ± 3.8 (γ = 17.34 mJ/m2, 40.2 of dispersive contribution) for C. albicans and H. pylori, respectively, (ii) hydrogen bonds between surface components of yeast and bacterium (e.g., -S-H⋅⋅⋅NH2- or -S-H⋅⋅⋅O[bond, double bond]CO-) and (iii) thiol-mediated surface interactions identified by displacements to lower wavenumbers (Δv = 5 cm-1). Evidence of internalization and electrostatic interactions were not evidenced. All observations were congruent with the biofilm formation, including the identification of small-size biostructures (i.e., 122-459 nm) associated with extracellular proteins, extracellular DNA, or outer membrane vesicles were observed characteristic of biofilm formation. Conclusion: It is concluded that biofilm is formed by co-aggregation after anchoring of H. pylori on C. albicans. Several surface interactions were associated with the prevalence of H. pylori, the possibility to find C. albicans in the stomach epithelium infected by H. pylori, but also, strength interactions could be interfering in experimental observations associated with bacterial-DNA detection in culture mixtures.

A critical analysis of environmental sustainability metrics applied to green synthesis of nanomaterials and the assessment of environmental risks associated with the nanotechnology.

Nanotechnology is one of the most relevant scientific areas today due to its multiple applications in fields such as medicine, environmental remediation, information technology and energy conversion. This importance has led to the need to advance in the development of environmentally sustainable and safe nanomaterials by incorporating the principles of green chemistry during their synthesis and in their applications. However, this qualitative framework of thought does not offer minimum criteria for the use of the term "green", and therefore, this adjective is commonly used to refer to bio-based or nanotechnological processes without taking into account their net ecological impact. In this context, environmental sustainability metrics can be applied to nanotechnology to compare, optimize and quantify the environmental sustainability of synthesis procedures. This review provides an overview of green chemistry and its application in nanotechnology, but also an analysis of the use of green chemistry principles in the development of bio-based nanobiotechnology and nanosynthesis, with special emphasis on the use of sustainability's metrics for the quantitative analysis of nanomaterial synthesis protocols. These include: Atom Economy, E-factor, Process Mass Intensity, Energy Intensity, and Life Cycle Analysis.

Clicker Training Accelerates Learning of Complex Behaviors but Reduces Discriminative Abilities of Yucatan Miniature Pigs.

Animal training is meant to teach specific behavioral responses to specific cues. Clicker training (CT) is a popular training method based on the use of a device that emits a sound of double-click to be associated as a first-order conditioned stimulus in contingency with positive reinforcements. After some repetitions, the clicker sound gains some incentive value and can be paired with the desired behavior. Animal trainers believed that CT can decrease training time compared to other types of training. Herein, we used two-month old miniature piglets to evaluate whether CT decreased the number of repetitions required to learn complex behaviors as compared with animals trained with voice instead of the clicker. In addition, we compared the number of correct choices of animals from both groups when exposed to object discriminative tests. Results indicated that CT decreased the number of repetitions required for pigs to learn to fetch an object but reduced the ability of animals to make correct choices during the discriminate trials. This suggests that CT is more efficient than voice to teach complex behaviors but reduces the ability of animals to use cognitive processes required to discriminate and select objects associated with reward.

Functional transformation of Fourier-transform mid-infrared spectrum for improving spectral specificity by simple algorithm based on wavelet-like functions.

Herein a simple algorithm for the mathematical transformation of FTIR spectrum was developed, evaluated, and applied for description of different systems. Water, ethanol, n-butanol, n-hexanol, formic acid, acetic acid, citric acid, and water-acetic acid mixtures at different concentrations were used as model systems. We found that functional transformation of FTIR spectrum can be performed by functionally-enhanced derivative spectroscopy approach using the Function P, which is defined as P = (1 + aj )(s)-0.5 where aj and s are the absorbance and the scale factor, respectively. It is also demonstrated that Function P can be used for qualitative and quantitative analysis of pure substances and mixtures. It is concluded that Function P can be understood as a wavelet transformation, which is evaluated at small times and displacements, with scaling factor given by the change of absorbance inverse.

Metal-ion retention properties of water-soluble amphiphilic block copolymer in double emulsion systems (w/o/w) stabilized by non-ionic surfactants.

Metal-ion retention properties of water-soluble amphiphilic polymers in presence of double emulsion were studied by diafiltration. Double emulsion systems, water-in-oil-in-water, with a pH gradient between external and internal aqueous phases were prepared. A poly(styrene-co-maleic anhydride) (PSAM) solution at pH 6.0 was added to the external aqueous phase of double emulsion and by application of pressure a divalent metal-ion stream was continuously added. Metal-ions used were Cu(2+) and Cd(2+) at the same pH of polymer solution. According to our results, metal-ion retention is mainly the result of polymer-metal interaction. Interaction between PSMA and reverse emulsion globules is strongly controlled by amount of metal-ions added in the external aqueous phase. In addition, as metal-ion concentration was increased, a negative effect on polymer retention capacity and promotion of flocculation phenomena were produced.

Anestesia local para cirugia en la región inguinal / Local anesthetic for inguinal region surgery

Se presenta la experiencia obtenida en la utilización de la técnica de Labat para el bloqueo anestésico local del campo inguinal en doscientas cincuenta y ocho intervenciones: ciento noventa y seis hernioplastias inguinales, treinta y ocho varicocelectomías y veinticuatro hidrocelectomías por vía inguinal. Se describe la técnica anestésica, haciendo hincapié en los aspectos de selección de los pacientes, las precauciones para evitar accidentes y los preparativos para enfrentarse a ellos con éxito. Recomendamos la extensión del aprendizaje y uso de este antiguo y útil método anestésico porque disminuye los costos de atención hospitalaria, facilita la cirugía ambulatoria, reduce la tasa de recurrencias y es una alternativa en aquellos casos de riesgo anestésico aumentado

Incontinencia urinaria de esfuerzo femenina experiencia con la colposuspensión de Burch / Female urinary stress incontinence: experience with the burch's colposuspension

Presentamos la experiencia adquirida en el Servicio de Cirugía General del Hospital Pastor Oropeza de Barquisimeto en el manejo y tratamiento de pacientes con incontinencia urinaria de esfuerzo que acompaña patologías ginecológicas que ameritan panhisterectomía abdominal. Se comparan los resultados obtenidos con la operación de colposuspensión suprapúbica de Burch contra los obtenidos realizados sólo la panhisterectomía abdominal, realizadas en dos grupos equiparables de pacientes. Los resultados obtenidos comparables a los reportados en otros estudios y nos estimulan a recomendar el uso de las técnicas de colposuspensión suprapúbica a los ligamentos de Cooper ("ligamentum pactineale") para curar esta inhabilitante y frecuente patología

Anestesia local para cirugía en la región inguinal / Local anesthesia for surgery in the inguinal area

Se presenta la experiencia obtenida en la utilización de la técnica de Labat para el bloqueo anestésico local del campo inguinal en ciento cuarenta intervenciones: ciento ocho hernioplastias inguinales, dieciocho varicocelectomías y catorce hidrocelectomías por vía inguinal. Se describe la técnica anestésica, haciendo hincapié en los aspectos de selección de los pacientes, las precauciones para evitar accidentes y los preparativos para enfrentarse a ellos con éxito. Recomendamos la extensión del aprendizaje y uso de este antiguo y útil método anestésico porque disminuye los costos de atención hospitalaria, facilita la cirugía ambulatoria, reduce la tasa de recurrencias y es una alternativa en aquellos casos de riesgo anestésico aumentado