The Debye length and anionic transport properties of composite membranes based on supported ionic liquid-like phases (SILLPS).

An analysis of the ionic transport properties of BMIM [NTf2] in supported ionic-liquid-like phase (SILLP)-based membranes has been carried out based on experimental impedance spectroscopy measurements. The direct current (dc)-conductivity was analyzed to determine the temperature and frequency dependence. The fit of the loss tangent curve data with the Cole-Cole approximation of the electrode polarization model provides the conductivity, diffusivity, and density of charge carriers. Among these quantities, a significant increase in conductivity is observed when an ionic liquid is added to the polymeric matrix containing imidazolium fragments. The use of a recent generalization of Eyring's absolute rate theory allowed the elucidation of how the local entropy restrictions, due to the porosity of the polymeric matrix, control the conductive process. The fit of the conductivity data as a function of temperature manifests the behavior of the excess entropy with respect to the temperature. The activation entropy and enthalpy were also determined. Our results correlate the Debye length (LD) with the experimental values of conductivity, electrode polarization relaxation time, and sample relaxation time involved. Our work provides novel insights into the description of ionic transport in membranes as the diffusivity, mobility, and free charge density depend on the LD. Moreover, we discuss the behavior of the polarization relaxation time, the sample relaxation time, and the static permittivity as a function of the temperature.

Dynamics of the orphan myosin MyoF over Trypanosoma cruzi life cycle and along the endocytic pathway.

Trypanosoma cruzi proliferative forms perform endocytosis through a specialized structure named the cytostome-cytopharynx complex (SPC). The SPC is a specialized invagination of the cell membrane that extends through the cell body towards the posterior regions, with its aperture close to the flagellar pocket. Recently, diverse proteins were found along the cytopharynx, including two myosin motors. One of these is the orphan myosin MyoF, that was proved to be essential for endocytosis in epimastigotes. However, the dynamics of MyoF localization along the endocytic pathway and through the T. cruzi life cycle remain unclear. Using CRISPR-Cas9 genome editing, we generated epimastigotes expressing MyoF fused to mNeonGreen from its endogenous locus. Using these cells, we observed that during the epimastigote cell cycle MyoF signal disappeared during G2, reappearing at early cytokinesis. Additionally, we show that MyoF localization during metacyclogenesis is compatible with the progressive disappearance of the SPC, being absent in metacyclic trypomastigotes. Detergent fractionation showed that MyoF was predominantly present in the insoluble fraction and immunolocalized at the SPC microtubules in whole-mount cytoskeleton preparations. Moreover, during tracer uptake through the SPC, MyoF followed the tracer along the endocytic pathway and was found in posterior compartments after 30 min. Taken together, the data suggest that MyoF may play a role not only at the cargo entry site but also along the endocytic pathway.

Correction: Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4.

Correction for 'Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4' by Andreu Andrio et al., Phys. Chem. Chem. Phys., 2019, 21, 12948-12960, DOI: 10.1039/C8CP07472K.

Lipoteichoic acid depletion in Lactobacillus impacts cell morphology and stress response but does not abolish mercury surface binding.

Lipoteichoic acid (LTA) is a key component of the cell wall of most Gram-positive bacteria and plays many structural and functional roles. In probiotic lactobacilli, the function of LTA in mediating bacteria/host cross-talk has been evidenced and it has been postulated that, owing to its anionic nature, LTA may play a role in toxic metal sequestration by these bacteria. However, studies on this last aspect employing strains unable to synthesise LTA are lacking. We have inactivated the LTA polymerase encoding gene ltaS in two different Lactobacillus plantarum strains. Analysis of LTA contents in wild-type and ltaS mutant strains corroborated the role of this gene as a major contributor to LTA synthesis in L. plantarum. The mutant strains displayed strain-dependent anomalous cell morphologies that resulted in elongated or irregular cells with aberrant septum formation. They also exhibited higher sensitivity to several stresses (osmotic and heat) and to antimicrobials that target the cell wall. The toxicity of inorganic [(Hg(II)] and organic mercury (methyl-Hg) was also increased upon ltaS mutation in a strain-dependent manner. However, the mutant strains showed 0 to 50% decrease in their capacity of Hg binding compared to their corresponding parental strains. This result suggests a partial contribution of LTA to Hg binding onto the cell surface that was dependent on the strain and the Hg form.

Mechanically interlocked 3D multi-material micromachines.

Metals and polymers are dissimilar materials in terms of their physicochemical properties, but complementary in terms of functionality. As a result, metal-organic structures can introduce a wealth of novel applications in small-scale robotics. However, current fabrication techniques are unable to process three-dimensional metallic and polymeric components. Here, we show that hybrid microstructures can be interlocked by combining 3D lithography, mold casting, and electrodeposition. Our method can be used to achieve complex multi-material microdevices with unprecedented resolution and topological complexity. We show that metallic components can be combined with structures made of different classes of polymers. Properties of both metals and polymers can be exploited in parallel, resulting in structures with high magnetic responsiveness, elevated drug loading capacity, on-demand shape transformation, and elastic behavior. We showcase the advantages of our approach by demonstrating new microrobotic locomotion modes and controlled agglomeration of swarms.

Entropic restrictions control the electric conductance of superprotonic ionic solids.

The crystallographic structure of solid electrolytes and other materials determines the protonic conductivity in devices such as fuel cells, ionic-conductors, and supercapacitors. Experiments show that a rise of the temperature in a narrow interval may lead to a sudden increase of several orders of magnitude of the conductivity of some materials, a process called a superprotonic transition. Here, we use a novel macro-transport theory for irregular domains to show that the change of entropic restrictions associated with solid-solid phase or structural transitions controls the sudden change of the ionic conductivity when the superprotonic transition takes place. Specifically, we deduce a general formula for the temperature dependence on the ionic conductivity that fits remarkably well experimental data of superprotonic transitions in doped cesium phosphates and other materials reported in the literature.

Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4.

We present an experimental study and a theoretical interpretation of the temperature dependence of the transport properties of doped CsH2PO4 salts in both protonic and superprotonic phases. Cesium phosphate based solid electrolytes are technologically relevant because their operational temperature range is about 100 to 300 °C in which a superprotonic transition may manifest depending on its mixed composition. The experimental study was carried out using impedance spectroscopy at the temperature range of 150-230 °C, and the protonic and superprotonic transport properties and proton concentrations were calculated and analyzed by using the electrode polarization, and the Debye and Cole-Cole models for the dielectric constant. We have shown that the transport properties predicted by the Cole-Cole model are consistent with the conductivity measurements whereas the Debye model shows some inconsistencies. We attribute this to the fact that the Cole-Cole model incorporates the effects of interactions among charge carriers better than the more commonly used Debye model. In this way, our work shows a more consistent approach to determine the transport properties of solid electrolytes and, therefore, provides a more reliable tool to analyze the transport properties of heterogeneous solid electrolytes that can be used in electrochemical devices, including fuel cells and supercapacitors.

Endoscopic submucosal dissection as treatment for early gastric cancer: Experience at two centers in Lima, Peru. / Disección submucosa endoscópica como tratamiento de cáncer gástrico temprano: experiencia en 2 centros de Lima, Perú.

INTRODUCTION AND AIMS: The aim of the present study was to evaluate the feasibility of endoscopic submucosal dissection (ESD) and determine the clinical and pathologic characteristics of early gastric cancers and premalignant lesions treated with that technique at the Hospital Nacional of the Department of Health and a private clinic in Lima, Peru. MATERIAL AND METHODS: A descriptive study of all pre-malignant and malignant gastric lesions treated with ESD at the Gastroenterology Service of the Hospital Arzobispo Loayza and the Clínica Angloamericana was conducted within the time frame of January 2012 and January 2017. RESULTS: A total of 13 lesions were resected through ESD: 8 adenocarcinomas (61.53%), 3 adenomas with high-grade dysplasia (23%), and 2 adenomas with low-grade dysplasia (15.38%). Twelve lesions (92.3%) were located in the lower third of the stomach. Slightly elevated lesions (Paris classification IIa) (4 lesions, 30.76%) and mixed slightly elevated lesions with a depressed component (IIa+IIc) (4 lesions, 30.76%) predominated. The mean size of the resected specimens was 35mm. Complete resection of all lesions was achieved in 11 cases (84.6%) and en bloc resection was carried out in 11 cases (84.6%). Resection was curative in 6 cases (75%), from the total of 8 resected adenocarcinomas. One case of perforation was the only complication reported (7.6%) and it was surgically resolved. CONCLUSIONS: The feasibility and efficacy of ESD for the treatment of early gastric cancer was demonstrated at two healthcare centers in Lima, Peru. The complication rate was similar to that reported in the international medical literature.

The use of lactic acid bacteria to reduce mercury bioaccessibility.

Mercury in food is present in either inorganic [Hg(II)] or methylmercury (CH3Hg) form. Intestinal absorption of mercury is influenced by interactions with other food components. The use of dietary components to reduce mercury bioavailability has been previously proposed. The aim of this work is to explore the use of lactic acid bacteria to reduce the amount of mercury solubilized after gastrointestinal digestion and available for absorption (bioaccessibility). Ten strains were tested by addition to aqueous solutions containing Hg(II) or CH3Hg, or to food samples, and submission of the mixtures to gastrointestinal digestion. All of the strains assayed reduce the soluble fraction from standards of mercury species under gastrointestinal digestion conditions (72-98%). However their effectiveness is lower in food, and reductions in bioaccessibility are only observed with mushrooms (⩽68%). It is hypothesized that bioaccessible mercury in seafood forms part of complexes that do not interact with lactic acid bacteria.

Characterization of the response to low pH of Lactobacillus casei ΔRR12, a mutant strain with low D-alanylation activity and sensitivity to low pH.

AIMS: To identify the differences that account for the acid sensitivity of Lactobacillus casei ΔRR12. RR12 controls the expression of the dlt operon, and its inactivation leads to a diminished teichoic acid D-alanylation activity. To this end, a comparison of its response of ΔRR12 to low pH with the parental strain Lact. casei BL23 was carried out. METHODS AND RESULTS: The ability to induce an acid tolerance response (ATR), fatty acid (FA) composition and proteome changes induced in both strains in response to acid were investigated. Results obtained showed that both strains induce a growth-phase-dependent ATR. However, significant differences in the content of FAs and membrane-associated proteins were detected. CONCLUSIONS: The greater abundance of cytoplasmic proteins in the membrane fraction of the mutant strain ΔRR12 suggests an increased permeability of the cell membrane in this strain. SIGNIFICANCE AND IMPACT OF THE STUDY: The analysis of the response to low pH of strain ΔRR12 indicated that the inactivation of TCS12 affected the content of FAs and proteins associated to the cell envelope. Increased abundance of cytoplasmic proteins suggested that low alanylation of teichoic acids affected the permeability of the cell membrane and possibly accounts for the acid sensitivity of strain ΔRR12.

Pre-emptive effect of dexamethasone and methylprednisolone on pain, swelling, and trismus after third molar surgery: a split-mouth randomized triple-blind clinical trial.

The aim of this study was to compare the effect of dexamethasone 8 mg and methylprednisolone 40 mg for the control of pain, swelling, and trismus following the extraction of impacted third molars. Sixteen healthy patients with a mean age of 20.3 (standard deviation 1.25) years received a single oral dose of either drug 1 h prior to each surgical procedure (left and right teeth). At 24, 48, and 72 h and 7 days following surgery, swelling was determined using linear measurements on the face and trismus was determined by maximal mouth opening. Postoperative pain was self-recorded by the patients using a visual analogue scale at 8-h intervals for a period of 72 h. Data analysis involved descriptive statistics and the Wilcoxon, and paired t tests (P < 0.05). Dexamethasone controlled swelling better than methylprednisolone at all postoperative evaluations (P < 0.02) and led to greater mouth opening 48 h after surgery (P = 0.029). No statistically significant difference was found between drugs with regard to pain. In conclusion, pre-emptive dexamethasone 8 mg demonstrated better control of swelling and limited mouth opening in comparison to methylprednisolone 40 mg, with no differences between drugs regarding pain control.

Carbon nanotubes: directions and perspectives in oral regenerative medicine.

One of the main goals of bone tissue engineering is to identify and develop new biomaterials and scaffolds for structural support and controlled cell growth, which allow for formation or replacement of bone tissue. Recently, carbon nanotubes (CNT) have emerged as a potential candidate for bone tissue engineering. CNT present remarkable mechanical, thermal, and electrical properties with easy functionalization capability and biocompatibility. In oral regenerative medicine, bone reconstruction is an essential requirement for functional rehabilitation of the stomatognathic system. Autologous bone still represents the gold standard graft material for bone reconstruction. However, the small amounts of bone available in donor regions, together with the high costs of surgeries, are critical aspects that hinder the selection of this procedure. Thus, CNT alone or combined with biopolymers have promise to be used as novel potential biomaterials for the restoration of bone defects. Indeed, recent evidence demonstrates CNT to be a feasible material that can increase the formation of bone in tooth sockets of rats. The purpose of this review is to summarize the recent developments in bone repair/regeneration with CNT or CNT-based composites. We further provide an overview of bone tissue engineering and current applications of biomaterials, especially of CNT, to enhance bone regeneration.

Palatal radicular groove: clinical implications of early diagnosis and surgical sealing.

Palatal radicular groove is a discreet alteration in tooth morphology, characterized by an invagination that begins near the cingulum of the tooth and moves in an apical direction. Clinically, palatal radicular groove may be associated with periodontal and/or endodontic problems. This paper describes a clinical case of a young patient with palatal radicular groove with no signs of periodontal disease or endodontic impairment. An early diagnosis was made and treatment consisted of surgical sealing of the defect. After a 2-year period, reexaminations demonstrated adequate hygiene, maintenance of tooth vitality and periodontal health. The early diagnosis and sealing of the groove observed surgically made the root surface smooth, avoiding subgingival bacterial plaque buildup, and preventing possible periodontal and/or pulp impairment stemming from the defect.

Response of Lactobacillus casei BL23 to phenolic compounds.

AIMS: To determine the inhibitory effect of phenolic compounds on Lactobacillus casei BL23, the role of two component signal transduction systems (TCS) and the response of Lact. casei BL23 to p-coumaric acid. METHODS AND RESULTS: Growth of Lact. casei BL23 and 17 derivative strains defective in each TCS harboured by this strain in the presence of p-coumaric acid, ferulic acid, caffeic acid or methyl gallate was monitored. Furthermore, changes in the protein content of Lact. casei BL23 when exposed to p-coumaric acid were evaluated by 2D-SDS-PAGE. Eleven proteins differentially expressed in the presence of p-coumaric acid were detected. Six of them could be identified: ClpP and HtrA, involved in protein turnover and folding, acetyl-CoA carboxylase, involved in lipid metabolism, and an arginyl-tRNA synthetase were more abundant, whereas PurL and PurN, involved in purine biosynthesis, were less abundant. CONCLUSIONS: No significant differences were observed between the parental strain and the TCS-defective mutants. p-Coumaric acid elicited a response against membrane and cytoplasmic damages. SIGNIFICANCE AND IMPACT OF THE STUDY: The inhibitory effect of phenolic compounds on Lact. casei BL23 has been determined. For the first time, cytoplasmic proteins presumably involved in the response of Lact. casei BL23 against p-coumaric acid have been identified.

[Percutaneous endoscopic gastrostomy: a 7 years experience long-term tube feeding. Follow-up]. / Gastrostomía Endoscópica Percutánea: 7 años de experiencia en nutrición enteral a largo plazo. Seguimiento clínico.

Percutaneous endoscopic gastrostomy (PEG) is the first choice method for long-term enteral feeding when the digestive tube is undamaged and the patients' survival is longer than 2 months. There are increasing series and indications reported and although it is a safe technique we should take into account an appropriate patient selection. The aim of this work was to analyze the follow-up of the patients undergoing percutaneous endoscopic gastrostomy (PEG) at a hospital with high assistance level and one of the referents for organ transplantation in our community, with the peculiarities that this may have on our series. We analyze a cohort of 73 patients submitted to PEG during the years 2000-2007 at the Reina Sofía Hospital of Córdoba. Neurological and ENT neoplasms and upper GI tract neoplasms are among the most frequent causes, with similar results to those reported in other series. We highlight the number of young patients with cystic fibrosis (CF) in our series with nutritional support through PEG complementing oral and nocturnal feeding, which has lead to improved nutritional parameters before lung transplant. In consequence, we therefore analyze patients' selection and their characteristics, the ethical and moral implications in some of these patients, such in neurological patients, their complications, mortality, and we mention as being of interest the transient and well tolerated indication in a subgroup of CF patients that deserves special mention.

Gastrostomía Endoscópica Percutánea: 7 años de experiencia en nutrición enteral a largo plazo. Seguimiento clínico / Percutaneous endoscopic gastrostomy: a 7 years experience long-term tube feeding. Follow-up

La Gastrostomía Endoscópica Percutánea (PEG) es el método de elección para la alimentación enteral a largo plazo, cuando el tubo digestivo está indemne, y la supervivencia de los pacientes es superior a 2 meses. Son cada vez más, las series comunicadas e indicaciones, a pesar de ser una técnica segura, debemos tener en cuenta una adecuada selección de los pacientes. El propósito de este trabajo es analizar el seguimiento de los pacientes sometidos a Gastrostomía Endoscópica Percutánea (PEG), en un Hospital de gran nivel asistencial y uno de los referentes de Trasplante de órganos en nuestra comunidad, con las peculiaridades que esto tiene en nuestra serie. Analizamos una cohorte de 73 pacientes sometidos a PEG, durante los años 2000 a 2007 en el Hospital Reina Sofía de Córdoba. Las Enfermedades Neurológicas y Neoplásicas de la esfera ORL y Digestiva alta son las causas más frecuentes, con resultados similares a los publicados en otras series. Destacamos, el número de paciente jóvenes con Fibrosis Quística (FQ), en nuestra serie, con soporte nutricional a través de PEG complementaria a la alimentación oral y nocturna, lo cual, ha supuesto una mejora de los parámetros nutricionales de cara al trasplante pulmonar. En consecuencia, analizamos las características de los pacientes, las implicaciones éticas y morales de algunos de ellos, como son los enfermos neurológicos, sus complicaciones y mortalidad. Destacamos con interés, la indicación transitoria y bien tolerada en un subgrupo de pacientes con FQ, que en nuestra serie merece especial mención (AU)

Percutaneous endoscopic gastrostomy (PEG) is the first choice method for long-term enteral feeding when the digestive tube is undamaged and the patients’ survival is longer than 2 months. There are increasing series and indications reported and although it is a safe technique we should take into account an appropriate patient selection. The aim of this work was to analyze the followup of the patients undergoing percutaneous endoscopic gastrostomy (PEG) at a hospital with high assistance level and one of the referents for organ transplantation in our community, with the peculiarities that this may have on our series. We analyze a cohort of 73 patients submitted to PEG during the years 2000-2007 at the Reina Sofía Hospital of Córdoba. Neurological and ENT neoplasms and upper GI tract neoplasms are among the most frequent causes, with similar results to those reported in other series. We highlight the number of young patients with cystic fibrosis (CF) in our series with nutritional support through PEG complementing oral and nocturnal feeding, which has lead to improved nutritional parameters before lung transplant. In consequence, we therefore analyze patients’ selection and their characteristics, the ethical and moral implications in some of these patients,such in neurological patients, their complications, mortality,and we mention as being of interest the transient and well tolerated indication in a subgroup of CF patients that deserves especial mention (AU)

La orientación empática en los estudiantes de medicina humana de la Universidad de San Martin de Porres / Empathetic orientation of the medical students from San Martin de Porres University

OBJETIVO: Conocer el nivel de orientación empática en los estudiantes de medicina de la Universidad San Martín de Porres. MATERIAL Y MÉTODOS: Es una investigación observacional, transversal descriptivo, realizada entre los meses de marzo y junio del año 2010. Participaron 193 alumnos de un universo de 1920, correspondientes a los años I, II, III, IV, V y VI de la carrera de Medicina Humana de la Universidad de San Martín de Porres. Se aplicó la Escala de Empatía Médica de Jefferson (EEMJ). Para el análisis de datos se emplearon medios descriptivos de frecuencia, porcentajes y desviaciones estándares. RESULTADOS: Los estudiantes de IV año obtuvieron el mayor puntaje (6,1) de orientación empática, sin embargo el I año obtuvo el menor puntaje (5,5). Las mujeres tuvieron un mayor puntaje de orientación empática que los hombres, 5,9 y 5,8 respectivamente. El grupo etario con mayor puntaje (5,9) de orientación empática fue el grupo de 25-28 años. CONCLUSIONES:Los alumnos que están en los niveles intermedios de la carrera de medicina humana (III y IV año de medicina), las mujeres y el grupo etario de 25 û 28 años obtuvieron mayores puntuaciones en la Escala de Empatía Médica de Jefferson...

OBJECTIVE: To know the empathetic orientation of the medical students from San Martin de Porres University. MATERIAL AND METHODS: This is an observational, cross-sectional descriptive study, carried out between the months on March and June, 2010. 193 out of 1920 students participated, who belonged to the levels I, II, II, IV, V and VI. The Jefferson Scale of Physician Empathy (JSPE) was applied. For the data analysis used descriptive means of frequency, percentages and standard deviations. RESULTS: The Fourth yearÆs students obtained the highest score (6,1) in the empathic guidance, however the first yearÆs students had the lowest score (5,5). Women had a higher score than men empathetic orientation, 5,9 and 5,8 respectively. The age group with the highest score (5,9) empathic orientation was the group of 25-28 years. CONCLUSIONS: The students who are level intermediate of human medicine carrier (III and IV levels of medicine), the female and the group of 25 to 28 years had the highest score in The Jefferson Scale Physician Empathy.