Mycosynthesis of silver nanoparticles: a review.

Metallic nanoparticles currently show multiple applications in the industrial, clinical and environmental fields due to their particular physicochemical characteristics. Conventional approaches for the synthesis of silver nanoparticles (AgNPs) are based on physicochemical processes which, although they show advantages such as high productivity and good monodispersity of the nanoparticles obtained, have disadvantages such as the high energy cost of the process and the use of harmful radiation or toxic chemical reagents that can generate highly polluting residues. Given the current concern about the environment and the potential cytotoxic effects of AgNPs, once they are released into the environment, a new green chemistry approach to obtain these nanoparticles called biosynthesis has emerged. This new alternative process counteracts some limitations of conventional synthesis methods, using the metabolic capabilities of living beings to manufacture nanomaterials, which have proven to be more biocompatible than their counterparts obtained by traditional methods. Among the organisms used, fungi are outstanding and are therefore being explored as potential nanofactories in an area of research known as mycosynthesis. For all the above, this paper aims to illustrate the advances in state of the art in the mycosynthesis of AgNPs, outlining the two possible mechanisms involved in the process, as well as the AgNPs stabilizing substances produced by fungi, the variables that can affect mycosynthesis at the in vitro level, the applications of AgNPs obtained by mycosynthesis, the patents generated to date in this field, and the limitations encountered by researchers in the area.

Long-term in vivo application of a potassium channel-based optogenetic silencer in the healthy and epileptic mouse hippocampus.

BACKGROUND: Optogenetic tools allow precise manipulation of neuronal activity via genetically encoded light-sensitive proteins. Currently available optogenetic inhibitors are not suitable for prolonged use due to short-lasting photocurrents, tissue heating, and unintended changes in ion distributions, which may interfere with normal neuron physiology. To overcome these limitations, a novel potassium channel-based optogenetic silencer, named PACK, was recently developed. The PACK tool has two components: a photoactivated adenylyl cyclase from Beggiatoa (bPAC) and a cAMP-dependent potassium channel, SthK, which carries a large, long-lasting potassium current in mammalian cells. Previously, it has been shown that activating the PACK silencer with short light pulses led to a significant reduction of neuronal firing in various in vitro and acute in vivo settings. Here, we examined the viability of performing long-term studies in vivo by looking at the inhibitory action and side effects of PACK and its components in healthy and epileptic adult male mice. RESULTS: We targeted hippocampal cornu ammonis (CA1) pyramidal cells using a viral vector and enabled illumination of these neurons via an implanted optic fiber. Local field potential (LFP) recordings from CA1 of freely moving mice revealed significantly reduced neuronal activity during 50-min intermittent (0.1 Hz) illumination, especially in the gamma frequency range. Adversely, PACK expression in healthy mice induced chronic astrogliosis, dispersion of pyramidal cells, and generalized seizures. These side effects were independent of the light application and were also present in mice expressing bPAC without the potassium channel. Light activation of bPAC alone increased neuronal activity, presumably via enhanced cAMP signaling. Furthermore, we applied bPAC and PACK in the contralateral hippocampus of chronically epileptic mice following a unilateral injection of intrahippocampal kainate. Unexpectedly, the expression of bPAC in the contralateral CA1 area was sufficient to prevent the spread of spontaneous epileptiform activity from the seizure focus to the contralateral hippocampus. CONCLUSION: Our study highlights the PACK tool as a potent optogenetic inhibitor in vivo. However, further refinement of its light-sensitive domain is required to avoid unexpected physiological changes.

Parásitos gastrointestinales en mamíferos silvestres cautivos en el Centro de Fauna de San Emigdio, Palmira (Colombia) / Gastrointestinal parasites in captive wild mammals at the fauna center from San Emigdio, Palmira (Colombia)

RESUMEN La parasitosis intestinal en mamíferos silvestres es una de las principales complicaciones debido a las condiciones exógenas del cautiverio; predisponen al animal a complicaciones fisiológicas o infecciones secundarias que impiden su rehabilitación y reintroducción. El objetivo de esta investigación fue determinar la presencia de parásitos gastrointestinales en mamíferos silvestres del Centro de Atención y Valoración de Fauna silvestre del Centro de Educación Ambiental San Emigdio, San Emigdio, Palmira (Colombia). Se tomaron muestras fecales de 25 animales cautivos en el Centro de Atención y Valoración y fueron analizadas mediante dos técnicas: a) montaje con solución salina al 0,85 % y solución de lugol al 1% y b) técnica de flotación por solución saturada (Sheather) con densidad de 1.28g/ml, encontrando un 36% de positividad. Se encontró Enterobius vermicularis, Fasciola sp., Entamoeba sp. y Ancylostoma sp. El grupo de primates no humanos presentó cargas parasitarias más altas con respecto a felinos, caninos y demás mamíferos del estudio. Los microorganismos identificados son reconocidos como parásitos causantes de complicaciones en animales cautivos y en libertad; al igual, son catalogados como posibles riesgos zoonóticos.

ABSTRACT Intestinal parasitosis in wild mammals is one of the main complications due to the exogenous conditions of captivity. They predispose the animal to physiological complications or secondary infections that prevent its rehabilitation and reintroduction. The objective is to determine the presence of gastrointestinal parasites in wild mammals from the Wildlife Care and Valuation Center of the San Emigdio Environmental Education Center, San Emigdio, Palmira (Colombia). Fecal samples were taken from 25 captive animals in Care and Valuation Center being analyzed using two techniques: a) assembly with 0.85% saline solution and 1% lugol solution and b) saturated solution flotation technique (Sheather) with a density of 1.28g/ml, with a 36% of positivity. Enterobius vermicularis, Fasciola sp., Entamoeba sp. and Ancylostoma sp. were found. The group of non-human primates had higher parasitic intensity compared to felines, canines and other mammals in the study. The identified microorganisms are recognized as parasites causing complications in captive animals and in free life; likewise, they are classified as possible zoonotic risks.

Assessment of trimethoprim-sulfamethoxazole susceptibility testing methods for fastidious Haemophilus spp.

OBJECTIVES: To compare the determinants of trimethoprim-sulfamethoxazole resistance with established susceptibility values for fastidious Haemophilus spp., to provide recommendations for optimal trimethoprim-sulfamethoxazole measurement. METHODS: We collected 50 strains each of Haemophilus influenzae and Haemophilus parainfluenzae at Bellvitge University Hospital. Trimethoprim-sulfamethoxazole susceptibility was tested by microdilution, E-test and disc diffusion using both Mueller-Hinton fastidious (MH-F) medium and Haemophilus test medium (HTM) following EUCAST and CLSI criteria, respectively. Mutations in folA, folP and additional determinants of resistance were identified in whole-genome-sequenced isolates. RESULTS: Strains presented generally higher rates of trimethoprim-sulfamethoxazole resistance when grown on HTM than on MH-F, independent of the methodology used (average MIC 2.6-fold higher in H. influenzae and 1.2-fold higher in H. parainfluenzae). The main resistance-related determinants were as follows: I95L and F154S/V in folA; 3- and 15-bp insertions and substitutions in folP; acquisition of sul genes; and FolA overproduction potentially linked to mutations in -35 and -10 promoter motifs. Of note, 2 of 19 H. influenzae strains (10.5%) and 9 of 33 H. parainfluenzae strains (27.3%) with mutations and assigned as resistant by microdilution were inaccurately considered susceptible by disc diffusion. This misinterpretation was resolved by raising the clinical resistance breakpoint of the EUCAST guidelines to ≤30 mm. CONCLUSIONS: Given the routine use of disc diffusion, a significant number of strains could potentially be miscategorized as susceptible to trimethoprim-sulfamethoxazole despite having resistance-related mutations. A simple modification to the current clinical resistance breakpoint given by the EUCAST guideline for MH-F ensures correct interpretation and correlation with the reference standard method of microdilution.

The effectiveness of a learning strategies program for university students / Eficacia de un programa de mejora de las estrategias de aprendizaje en la enseñanza superior

Background: University lecturers often complain about their students' lack of learning strategies, but not many universities in Spain offer specific courses in this area. Studies on their effectiveness are also rare. Method: This study presents the results of a Learning Strategies Course implemented at the School of Teacher Training and Education, University of Oviedo, Spain. A quasi-experimental design was used with an experi-mental (n = 60) and a control group (n = 57) of students on the Educational Psychology course. A Spanish adaptation of the Motivated Strategies for Learning Questionnaire (MSLQ): the CEAMR2 was used as a pre and post-test measure. Group A (EG) received training in learning strategies, while group B (CG) received no training. Results: Post-test measures showed significant differences in five out of the ten learning strategies assessed: elaboration, organization, repetition, self-questioning and study space, and also an improvement in one out of the six motivational scales: control of learning beliefs. Discussion: The results suggest that learning strategies courses with proven effectiveness should be offered to university students (AU)

Antecedentes: los profesores universitarios se quejan de la forma de estudiar sus alumnos, pero escasean en nuestro país cursos específicos en este área y estudios sobre su eficacia. Método: presentamos los resultados obtenidos con el Curso de Estrategias de Aprendizaje en un grupo de estudiantes de la Facultad de Formación del Profesorado y Educación de la Universidad de Oviedo. Se utilizó un diseño quasi-experimental con grupo experimental (n = 60) y grupo de control(n = 57), formados por estudiantes de primer curso de la asignatura Psicología de la Educación. Se utilizó el Cuestionario de Estrategias de Aprendizaje y Motivación (CEAM-R2), adaptación del MSLQ, como medida pre y post-test. El grupo A (GE) recibió entrenamiento en estrategias de aprendizaje, mientras que el grupo B (GC) no lo recibió. Resultados: el posttest muestra diferencias significativas en cinco de las diez estrategias de aprendizaje evaluadas: elaboración, organización, repetición, auto-interrogación y lugar de estudio, y también en una de las seis escalas motivacionales: creencias de control del aprendizaje. Discusión: los resultados sugieren que se deberían ofertar a los universitarios cursos de estrategias de aprendizaje eficaces (AU)

The effectiveness of a learning strategies program for university students.

BACKGROUND: University lecturers often complain about their students’ lack of learning strategies, but not many universities in Spain offer specific courses in this area. Studies on their effectiveness are also rare. METHOD: This study presents the results of a Learning Strategies Course implemented at the School of Teacher Training and Education, University of Oviedo, Spain. A quasi-experimental design was used with an experi-mental (n = 60) and a control group (n = 57) of students on the Educational Psychology course. A Spanish adaptation of the Motivated Strategies for Learning Questionnaire (MSLQ): the CEAMR2 was used as a pre and post-test measure. Group A (EG) received training in learning strategies, while group B (CG) received no training. RESULTS: Post-test measures showed significant differences in five out of the ten learning strategies assessed: elaboration, organization, repetition, self-questioning and study space, and also an improvement in one out of the six motivational scales: control of learning beliefs. DISCUSSION: The results suggest that learning strategies courses with proven effectiveness should be offered to university students.

High resolution imaging of 2D distribution of lithium in thin samples measured with multipixel detectors in sandwich geometry.

A method that enables visualization of lateral distribution of Li in thin films is described. The method is based on the simultaneous detection of the reaction products of the 6Li(n,α)t nuclear reaction with thermal neutrons measured with two multipixel detectors in a sandwich geometry with a sample. Here, the principle and basic methodological parameters of the method, including tests with thin polymers with known Li microstructure, are discussed.

Characterization of Pseudomonas chlororaphis from Theobroma cacao L. rhizosphere with antagonistic activity against Phytophthora palmivora (Butler).

AIM: To isolate and characterize rhizobacteria from Theobroma cacao with antagonistic activity against Phytophthora palmivora, the causal agent of the black pod rot, which is one of the most important diseases of T. cacao. METHODS AND RESULTS: Among 127 rhizobacteria isolated from cacao rhizosphere, three isolates (CP07, CP24 and CP30) identified as Pseudomonas chlororaphis, showed in vitro antagonistic activity against P. palmivora. Direct antagonism tested in cacao detached leaves revealed that the isolated rhizobacteria were able to reduce symptom severity upon infection with P. palmivora Mab1, with Ps. chlororaphis CP07 standing out as a potential biocontrol agent. Besides, reduced symptom severity on leaves was also observed in planta where cacao root system was pretreated with the isolated rhizobacteria followed by leaf infection with P. palmivora Mab1. The production of lytic enzymes, siderophores, biosurfactants and HCN, as well as the detection of genes encoding antibiotics, the formation of biofilm, and bacterial motility were also assessed for all three rhizobacterial strains. By using a mutant impaired in viscosin production, derived from CP07, it was found that this particular biosurfactant turned out to be crucial for both motility and biofilm formation, but not for the in vitro antagonism against Phytophthora, although it may contribute to the bioprotection of T. cacao. CONCLUSIONS: In the rhizosphere of T. cacao, there are rhizobacteria, such as Ps. chlororaphis, able to protect plants against P. palmivora. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides a theoretical basis for the potential use of Ps. chlororaphis CP07 as a biocontrol agent for the protection of cacao plants from P. palmivora infection.

BLOC Screening en una muestra de niños chilenos / Screening BLOC in a sample of chilean children

El objetivo de este artículo es analizar las propiedades psicométricas de BLOC-S en una muestra de 228 niños chilenos. Los niveles de fiabilidad fueron de 0,88, 0,92, 0,76 y 0,91 para el módulo morfológico, sintáctico, semántico y pragmático respectivamente. Un análisis factorial exploratorio de los bloques que constituyen cada módulo, produjo una solución básicamente unidimensional que explica el 30,13% de la varianza. No se encontraron diferencias por sexo. Por nivel socioeconómico encontramos que los niños de nivel alto tenían mejor desempeño que los de nivel medio y bajo, en todos los módulos. Las diferencias por edad fueron pequeñas en todos los módulos, generando entre tres y cuatro grupos homogéneos con evidente sobreposición. La baja capacidad discriminativa probablemente se deba a una reducida variabilidad, debida al bajo desempeño general de la muestra chilena comparada con la española

The aim of this work was to analyse the psychometric properties of the Screening Objective and Criterial Language Battery (BLOC-S). In a sample of 228 Chilean children, levels of reliability were 0.88, 0.92, 0.76 y 0.91 for morphologic, syntactic, semantic and pragmatic modules, respectively. An exploratory factorial analysis produced unidimentional solution, explaining 30.13% of the variance. We did not find differences in performance by sex. By socio-economic status, higher status children performed better than those of middle and lower status, in all modules. Differences by age were small in all modules; producing between 3 and 4 homogeneous groups with substantial overlap. Lack of discrimination is probably related to reduce variability, due to low performance in the Chilean sample compared to Spain

Embarazo heterotópico e hiperestimulación ovárica / Heterotopic pregnancy and ovarian hyperstimulation

Se presenta un caso de embarazo combinado intrauterino y extrauterino, conseguido mediante fecundación in vitro, en el que coexistió una hiperestimulación ovárica moderada, lo que dificultó el diagnóstico precoz al solaparse la sintomatología de ambas entidades clínicas (AU)

We report a case of combined intra-uterine and extra-uterine pregnancy, achieved by in vitro fertilization. The coexistence of moderate ovarian hyperstimulation with overlapping symptoms of both entities hampered early diagnosis (AU)

Gestación gemelar con feto acardio-acéfalo / Twin gestation with an afacial and acephalic fetus

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[Gastric epithelioid leiomyosarcoma (malignant leiomyoblastoma). Report of a case and review of the world literature]. / Leiomiosarcoma epitelioide gástrico (Leiomioblastoma maligno). Reporte de un caso y revisión de la literatura mundial.

The authors report a case of gastric epithelial leiomyoma. (Leiomyoblastoma). Macroscopically, such tumors resemble leiomyoma, with a biological behavior between leiomyoma and leiomyosarcoma. A review of the medical literature indicates that gastrointestinal bleeding in the most usual manifestation. The endoscopy biopsy, many times, is unable to confirm the malignant or benign of the tumor. It is emphasized the importance of identifying the potentially malignant tendency of the tumor, indicated, mainly, by histology consist in total gastric resection. Radiology, Ultrasound and Endoscopy are the most frequently used methods to arrive at diagnosis. In our case a patient with a presumed diagnosis of gastric cancer with a severe upper gastrointestinal hemorrhage was operated on as an emergency. A radical extended total gastrectomy was performed. Intraoperative findings included multiple pancreatic, hepatic, splenic, hilium, greater and lesser omental metastases. The patient was released in good condition but died 3 months later.

[Solitary rectal polyp and endoscopic polypectomy in a pediatric population: 3 years' experience]. / Pólipo rectal solitario y polipectomía endoscópica en una población pediátrica: experiencia de 3 años.

During defecation, rectal polyps represent one most frequent causes of bleeding in infancy. The advent of endoscopic polypectomy has resulted very useful in their treatment. From January 1987 to March 1990, 113 children with rectal bleeding were evaluated; 22 of them had solitary rectal polyp, between 5 to 15 cm from anal margin at rectoscopy. 6 patients were excluded because they had autoamputation of the polyp, 16 patients, 9 girls and 6 boys between 2 and 11 years of age were studied with blood tests, series stools, contrast study with barium, colonoscopy with polypectomy and polyp histology investigation. 14 patients had chronic anemia, 10 had parasitic in stools. The barium enema identified rectal polyps in 14 patients (87.5%), colonoscopy and polypectomy was performed in every children. Juvenile histologic type predominated (82%). It is demonstrated that chronic anemia can follow rectal bleeding by polyps in children. Parasitic infections such as tricocephalous in conjunction with solid feces, may have a traumatic effect and produce chronic inflammation. Double contrast X-rays of the colon is useful to identify polyps. Non complications were observed during or after polypectomy. It is demonstrated that endoscopic polypectomy in children is a simple, safety and effective method.