Starch-based films affected by the addition of collagen from Prochilodus magdalenae residues and HPMC: Application in Andean blackberry (Rubus glaucus Benth) coatings.

Starch-based films offer the advantages of biodegradability, edibility, barrier properties, flexibility, and adaptability. This study compared the physicochemical properties of starch-based films by adding raw fish collagen and hydroxypropylmethylcellulose (HPMC). The tensile properties were evaluated, and the interaction with water was analyzed. Barrier properties, such as water vapor and oxygen permeability, were examined, and optical properties, such as gloss and good internal transmittance, were evaluated. The films were evaluated as coatings on Andean blackberries (Rubus glaucus Benth) for 2 weeks at 85% RH and 25°C. The results showed that the inclusion of collagen caused a reduction in the tensile strength and elastic modulus of the films. Also, the formulation with the highest collagen concentration (F7) exhibited the lowest weight loss and water vapor permeability, also it had the highest collagen concentration and showed the highest reduction in Xw and WAC, with values of 0.048 and 0.65 g water/g dry film, respectively. According to analyzing the optical properties, F1 presented the highest bright-ness and transmittance values, with 18GU and 82 nm values, respectively. In general, the films and coatings are alternatives to traditional packaging materials to prolong the shelf life of these fruits.

Development of films based on chitosan, gelatin and collagen extracted from bocachico scales (Prochilodus magdalenae).

Biodegradable biopolymers from species of the animal kingdom or their byproducts are sustainable as ecological materials due to their abundant supply and compatibility with the environment. The research aims to obtain a biodegradable active material from chitosan, gelatin, and collagen from bocachico scales (Prochilodus magdalenae). Regarding the methodology, films were developed from gelatin, chitosan, and collagen from bocachico scales (Prochilodus magdalenae) at different concentrations using glycerol as a plasticizer and citric acid as a cross-linker. The films were obtained with the hydrated mass processed by compression molding and characterized according to humidity, water solubility, contact angle, mechanical properties, and structural properties. The results of the films showed a hydrophobic characteristic. First, the chitosan-collagen (CS/CO) films showed a yellowish color, while the gelatin-collagen (Gel/CO) films were transparent and less soluble than the gelatin-collagen (Gel/CO) films. Concerning mechanical properties, gelatin films showed higher stiffness and tensile strength than chitosan films. Furthermore, in the morphological analysis, more homogeneous chitosan films were obtained by increasing the concentration of citric acid. In general, chitosan, gelatin, and collagen extracted from the scales of the bocachico (Prochilodus magdalenae) are an alternative in the application of films in the food industry.

Acid-induced disassembly of the Haemophilus ducreyi cytolethal distending toxin.

The cytolethal distending toxins (CDTs) produced by many Gram-negative pathogens are tripartite genotoxins with a single catalytic subunit (CdtB) and two cell-binding subunits (CdtA + CdtC). CDT moves by vesicle carriers from the cell surface to the endosomes and through the Golgi apparatus en route to the endoplasmic reticulum (ER). CdtA dissociates from the rest of the toxin before reaching the Golgi apparatus, and CdtB separates from CdtC in the ER. The free CdtB subunit, which is only active after holotoxin disassembly, then crosses the ER membrane and enters the nucleus where it generates DNA breaks. We hypothesized that the acidified lumen of the endosomes is responsible for separating CdtA from the CdtB/CdtC heterodimer. To test this prediction, possible acid-induced disruptions to the CDT holotoxin were monitored by size exclusion chromatography and surface plasmon resonance. We found that CDT could not efficiently assemble from its individual subunits at the early endosome pH of 6.3. Partial disassembly of the CDT holotoxin also occurred at pH 6.3, with complete separation of CdtA from an intact CdtB/CdtC heterodimer occurring at both pH 6.0 and the late endosome pH of 5.6. Acidification caused the precipitation of CdtA at pH 6.5 and below, but neither CdtB nor CdtC were affected by a pH as low as 5.2. Circular dichroism further showed that the individual CdtB subunit adopts a different secondary structure as compared to its structure in the holotoxin. We conclude the first stage of CDT disassembly occurs in the early endosomes, where an acid-induced alteration to CdtA releases it from the CdtB/CdtC heterodimer.

Childhood leukemia and non-Hodgkin's lymphoma survivors lack knowledge about their past disease and possible late effects. I-BFM ELTEC study with Chilean and Croatian participation.

PURPOSE: Late effects in childhood cancer survivors are a major cause of morbidity and mortality. The objective was to establish knowledge about the disease, late effects, self-care practices, application of health knowledge/education, sources of information, and biopsychosocial impact of cancer, and compare the results of Chile and Croatia. METHODS: One-hundred-and-seventy-one, 5-year survivors who were treated for leukemia or non-Hodgkin's lymphoma responded to a questionnaire (119 in Chile and 52 in Croatia). The questionnaire was reviewed by BFM-ELTEC. RESULTS: Health knowledge about past diagnosis and general treatment had 96% Chilean and 85% Croatian survivors. Ninety percent of Chilean and 73% of Croatian survivors were unaware of possible late effects, and half did not know which specialist to visit for follow-up. Forty-six percent of Chilean and 35% of Croatian survivors knew about healthy lifestyles, but most did not practice them. The 74% of Chileans and 87% of Croatian survivors recalled having received health education during treatment. About 50% of survivors in both groups were afraid or anguish, but it was also a growth experience for 60% of Chilean and 42% of Croatian survivors. Eighty-seven percent Chilean and 77% Croatian survivors considered themselves physically independent, while 76% and 75% felt psychologically independent, respectively. CONCLUSION: A significant lack of knowledge about the specific treatment, late effects, and future health in both countries was detected. They did not achieve significant learning with the education received. Psychological sequelae were found that are important to prevent.

Effectiveness of probiotics in the prevention of carious lesions during treatment with fixed orthodontic appliances

The difficulty experienced by patients with fixed orthodontic appliances in maintaining adequate oral hygiene poses a risk for dental caries. The use of probiotics has been proposed as a means of prevention. The following systematic review aims to determine the effectiveness of probiotics in the prevention of dental caries during treatment with fixed orthodontic appliances. This review was carried out according to the PRISMA guidelines. A comprehensive electronic search was conducted in the Cochrane Library, EMBASE, PubMed and Google Scholar Beta databases. The inclusion criteria included randomized controlled clinical trials involving the use of probiotics, caries and patients under fixed orthodontic treatment. The methodological quality of the articles was evaluated according to risk of bias. Of the five included studies, three reported significant differences compared to the control group. Of the others, one article reported significant decrease in the final count of microorganisms compared to the beginning of treatment. Only one study reported no differences of any kind. It was estimated that the eligible studies were of moderate methodological quality and had an unclear risk of bias, without affecting key domains for the research. It is concluded that the daily consumption of probiotics can be effective in the prevention of carious lesions in patients under fixed orthodontic treatment. However, this should be interpreted with caution and corroborated by clinical trials of better methodological quality

A case in support of implementing innovative bio-processes in the metal mining industry.

The metal mining industry faces many large challenges in future years, among which is the increasing need to process low-grade ores as accessible higher grade ores become depleted. This is against a backdrop of increasing global demands for base and precious metals, and rare earth elements. Typically about 99% of solid material hauled to, and ground at, the land surface currently ends up as waste (rock dumps and mineral tailings). Exposure of these to air and water frequently leads to the formation of acidic, metal-contaminated run-off waters, referred to as acid mine drainage, which constitutes a severe threat to the environment. Formation of acid drainage is a natural phenomenon involving various species of lithotrophic (literally 'rock-eating') bacteria and archaea, which oxidize reduced forms of iron and/or sulfur. However, other microorganisms that reduce inorganic sulfur compounds can essentially reverse this process. These microorganisms can be applied on industrial scale to precipitate metals from industrial mineral leachates and acid mine drainage streams, resulting in a net improvement in metal recovery, while minimizing the amounts of leachable metals to the tailings storage dams. Here, we advocate that more extensive exploitation of microorganisms in metal mining operations could be an important way to green up the industry, reducing environmental risks and improving the efficiency and the economy of metal recovery.

Complejidad textual, lecturabilidad y rendimiento lector en una prueba de comprensión en escolares adolescentes / Textual Complexity, Readability and Reading Performance on a Comprehension Test in Adolescents School

En este artículo se estudia el problema de la lecturabilidad -la dificultad intrínseca de los textos para ser comprendidos- desde una perspectiva psicolingüística. El objetivo de este estudio fue establecer en qué medida la lecturabilidad de un texto depende no solo de sus propiedades estructurales (complejidad lingüística), sino también de las habilidades del lector y de la naturaleza de las tareas de comprensión. Se realizó una investigación de tipo cuasiexperimental en la que se construyeron dos pruebas de comprensión de lectura, manipulando la complejidad de los textos. Las pruebas incluyeron ítems para medir diversos aspectos de la comprensión según un modelo de evaluación basado en un enfoque teórico psicolingüístico. Las pruebas fueron aplicadas a 208 escolares de tres tipos de establecimientos educativos distintos. Los resultados de los análisis estadísticos de los datos permiten confirmar la hipótesis de que la lecturabilidad de los textos no depende solo de las propiedades textuales, sino de la relación de estas con las características de los lectores y las tareas de comprensión definidas en las pruebas.

In this paper, the problem of readability is studied from a psycholinguistic perspective. Readability is the intrinsic difficulty of texts to be understood. The aim of this study was to determine to what extent the readability of a text depends not only on its structural properties (linguistic complexity), but also the skills of the reader and the nature of comprehension tasks. An experimental research was carried out, in which two reading comprehension tests were developed by manipulating the complexity of texts. The tests included items to measure various aspects of comprehension according to an evaluation model based on a theoretical psycholinguistic approach. The tests were applied to 208 participants in three different types of schools. The results confirmed the hypothesis that the readability of texts depends not only on the textual properties, but also on the relationship of these with the readers' characteristics and the comprehension tasks defined in the tests.

Continuous bioscorodite crystallization in CSTRs for arsenic removal and disposal.

In CSTRs, ferrous iron was biologically oxidized followed by crystallization of scorodite (FeAsO(4)·2H(2)O) at pH 1.2 and 72 °C. The CSTRs were fed with 2.8 g L(-1) arsenate and 2.4 g L(-1) ferrous and operated at an HRT of 40 h, without seed addition or crystal recirculation. Both oxidation and crystallization were stable for periods up to 200 days. The arsenic removal efficiency was higher than 99% at feed Fe/As molar ratios between 1 and 2, resulting in effluents with 29 ± 18 mg As L(-1). Arsenic removal decreased to 40% at feed Fe/As molar ratios between 2 and 5. Microorganisms were not affected by arsenic concentrations up to 2.8 g As(5+) L(-1). The bioscorodite solid yield was 3.2 g/g arsenic removed. Bioscorodite crystals precipitated as aggregates, causing scaling on the glass wall of the reactor. The observed morphology through SE microscopy of the precipitates appeared amorphous but XRD analysis confirmed that these were crystalline scorodite. Arsenic leaching of bioscorodite was 0.4 mg L(-1) after 100 days under TCLP conditions, but when jarosite had been co-precipitated leaching was higher at 0.8 g L(-1). The robustness of the continuous process, the high removal efficiency and the very low arsenic leaching rates from bioscorodite sludge make the process very suitable for arsenic removal and disposal.

Kinetics of ferrous iron oxidation by batch and continuous cultures of thermoacidophilic Archaea at extremely low pH of 1.1-1.3.

The extreme acid conditions required for scorodite (FeAsO4·2H2O) biomineralization (pH below 1.3) are suboptimal for growth of most thermoacidophilic Archaea. With the objective to develop a continuous process suitable for biomineral production, this research focuses on growth kinetics of thermoacidophilic Archaea at low pH conditions. Ferrous iron oxidation rates were determined in batch-cultures at pH 1.3 and a temperature of 75°C for Acidianus sulfidivorans, Metallosphaera prunea and a mixed Sulfolobus culture. Ferrous iron and CO2 in air were added as sole energy and carbon source. The highest growth rate (0.066 h⁻¹) was found with the mixed Sulfolobus culture. Therefore, this culture was selected for further experiments. Growth was not stimulated by increase of the CO2 concentration or by addition of sulphur as an additional energy source. In a CSTR operated at the suboptimal pH of 1.1, the maximum specific growth rate of the mixed culture was 0.022 h⁻¹, with ferrous iron oxidation rates of 1.5 g L⁻¹ d⁻¹. Compared to pH 1.3, growth rates were strongly reduced but the ferrous iron oxidation rate remained unaffected. Influent ferrous iron concentrations above 6 g L⁻¹ caused instability of Fe²âº oxidation, probably due to product (Fe³âº) inhibition. Ferric-containing, nano-sized precipitates of K-jarosite were found on the cell surface. Continuous cultivation stimulated the formation of an exopolysaccharide-like substance. This indicates that biofilm formation may provide a means of biomass retention. Our findings showed that stable continuous cultivation of a mixed iron-oxidizing culture is feasible at the extreme conditions required for continuous biomineral formation.

Biogenic scorodite crystallization by Acidianus sulfidivorans for arsenic removal.

Scorodite is an arsenic mineral with the chemical formula FeAsO(4)*2H(2)O. It is the most common natural arsenate associated with arsenic-bearing ore deposits. In the present study we show that the thermoacidophilic iron-oxidizing archaeon Acidianus sulfidivorans is able to precipitate scorodite in the absence of any primary minerals or seed crystals, when grown on 0.7 g L(-1) ferrous iron (Fe(2+)) at 80 degrees C and pH 1 in the presence of 1.9 g L(-1) arsenate (H(3)AsO(4)). The simultaneous biologically induced crystallization of ferric iron (Fe(3+)) and arsenic to scorodite prevented accumulation of ferric iron. As a result, crystal growth was favored over primary nucleation which resulted in the formation of highly crystalline biogenic scorodite very similar to the mineral scorodite. Because mineral scorodite has a low water solubility and high chemical stability, scorodite crystallization may form the basis for a novel method for immobilization of arsenic from contaminated waters with high arsenic concentrations.

Causas organico-quirurgicas de dolor abdominal en niños preescolares y mayores / Surgical-organic causes of abdominal pain in pre-school children and olders

Realizamos un estudio transversal prospectivo de las causas orgánico-quirúrgicas del dolor abdominal en niños preescolares y mayores en la Clínica Infantil Dr. Robert Reid Cabral en el período septiembre 1992-junio 1993. De total de intervenidos (182 casos) el 84//correspondió a la apendicitis aguda como la causa orgánico quirúrgica más frecuente del dolor abdominal seguida por el trauma abdominal con 10 casos (5//). Causas de dolor abdominal, dolor abdominal