Microaeration promotes volatile siloxanes conversion to methane and simpler monomeric products.

The ubiquitous use of volatile siloxanes in a myriad of product formulations has led to a widespread distribution of these persistent contaminants in both natural ecosystems and wastewater treatment plants. Microbial degradation under microaerobic conditions is a promising approach to mitigate D4 and D5 siloxanes while recovering energy in wastewater treatment plants. This study examined D4/D5 siloxanes biodegradation under both anaerobic and microaerobic conditions ( [Formula: see text]  = 0, 1, 3 %) using wastewater sludge. Results show that the use of microaeration in an otherwise strictly anaerobic environment significantly enhances siloxane conversion to methane. 16S rRNA gene sequencing identified potential degraders, including Clostridium lituseburense, Clostridium bifermentans and Synergistales species. Furthermore, chemical analysis suggested a stepwise siloxane conversion preceding methanogenesis under microaerobic conditions. This study demonstrates the feasibility of microaerobic siloxane biodegradation, laying groundwork for scalable removal technologies in wastewater treatment plants, ultimately highlighting the importance of using bio-based approaches in tackling persistent pollutants.

Observed kinetics for the production of diethyl carbonate from CO2 and ethanol catalyzed by CuNi nanoparticles supported on activated carbon.

Monometallic and bimetallic Cu:Ni catalysts with different Cu:Ni molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) were synthesized by wetness impregnation on activated carbon and characterized by TPR (temperature programmed reduction), XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy). The synthesized catalysts were evaluated in the gas phase production of diethyl carbonate from ethanol and carbon dioxide. The largest catalytic activity was obtained over the bimetallic catalyst with a Cu:Ni molar ratio of 3:1. Its improved activity was attributed to the formation of a Cu-Ni alloy on the surface of the catalyst, evidenced by XPS and in agreement with a previous assignment based on Vegard law and TPR analysis. During the reaction rate experiments, it observed the presence of a maximum of the reaction rate as a function of temperature, a tendency also reported for other carbon dioxide-alcohol reactions. It showed that the reaction rate-temperature data can be adjusted with a reversible rate equation. The initial rate as a function of reactant partial pressure data was satisfactorily adjusted using the forward power law rate equation and it was found that the reaction rate is first order in CO2 and second order in ethanol.

Enhanced Cellulose Extraction from Banana Pseudostem Waste: A Comparative Analysis Using Chemical Methods Assisted by Conventional and Focused Ultrasound.

This study investigates the effectiveness of various chemical methods, both ultrasound-assisted and non-assisted, for extracting cellulose from banana pseudostem (BPS) waste, comparing the results with commercial pine and eucalyptus cellulose fibers. Delignification treatments with NaOH (25% and 30%) and H2O2 (8%) were evaluated, applied with both conventional and focused sonication. Ultrasound-assisted methods, particularly with NaOH, achieved cellulose percentages as high as 99.5%. X-ray diffraction (XRD) analysis revealed that NaOH treatments significantly increased the cellulose crystallinity index, reaching up to 67.9%, surpassing commercial fibers. Scanning electron microscopy (SEM) results showed that NaOH treatments, especially at 30%, improved fiber morphology and exposure. Thermogravimetric analysis (TGA) indicated that methods using NaOH and focused sonication enhanced the thermal stability of the cellulose. Compared to commercial fibers, some samples obtained with the proposed methods demonstrated higher purity, yield, and thermal stability, highlighting the effectiveness of ultrasound-assisted and NaOH methods.

[Promoting responsible consumption and production of scientific information in orthopedics]. / Fomentando la responsabilidad en el consumo y producción de información científica en ortopedia.

No Abstract available.

Kinetic Study of Liquid-Phase Glycerol Hydrodeoxygenation into 1,2-Propanediol over CuPd/TiO2-Na.

Hydrodeoxygenation (HDO) kinetics of glycerol into 1,2-propanediol (1,2-PDO) in the liquid phase is studied on Cu-Pd/TiO2 catalysts. At a stirring speed higher than 480 rpm and an average diameter of the catalyst particles smaller than 89.5 µm, no mass transfer resistance artifacts are observed. The increasing temperature and H2 concentration promote the glycerol conversion and the selectivity to 1,2-PDO and disfavor the selectivity to acetol. Based on the experimental data, empirical kinetic pseudo-homogeneous expressions are proposed for glycerol disappearance, 1,2-PDO formation, and acetol formation in the catalytic system. Dependence of the disappearance rate of glycerol is closer to 1 with respect to glycerol and nonmeaningful with respect to H2. The formation rate of 1,2-PDO is not highly dependent on the initial concentration of glycerol or H2, and the formation rate of acetol is directly dependent on glycerol and inversely dependent on H2, since it accelerates acetol conversion to 1,2-PDO. The activation energies for glycerol disappearance (77.8 kJ/mol), 1,2-PDO formation (51.2 kJ/mol), and acetol formation (84.6 kJ/mol) evidenced the selective formation of 1,2-PDO in this catalytic system.

Microaerobic conditions in anaerobic sludge promote changes in bacterial composition favouring biodegradation of polymeric siloxanes.

Volatile organic silicon compounds (VOSiC) are harmful pollutants to the biota and ecological dynamics as well as biogas-based energy conversion systems. However, there is a lack of understanding regarding the source of VOSiCs in biogas, especially arising from the biochemical conversion of siloxane polymers such as polydimethylsiloxanes (PDMS). The biodegradation of PDMS was evaluated under anaerobic/microaerobic conditions (PO2 = 0, 1, 3, 5%), using wastewater treatment plant (WWTP) sludge as an inoculum and PDMS as a co-substrate (0, 50, 100, 500 ppm). On average, strictly anaerobic treatments produced significantly less methane than the 3 and 5% microaerated ones, which show the highest PMDS biodegradation at 50 ppm. Thauera sp. and Rhodococcus sp. related phylotypes were identified as the most abundant bacterial groups in microaerated treatments, and siloxane-related molecules were identified as remnants of PDMS catabolism. Our study demonstrates that microaeration promotes changes to the native bacterial community which favour the biological degradation of PDMS. This confirms that the presence of VOSiC (e.g., D4-D6) in biogas is not only due to its direct input in wastewaters, but also to the PDMS microbial catabolism. Microaerobic conditions enhance both PDMS and (subsequent) VOSiC degradation in the liquid phase, increasing the concentrations of D4 and D5 in biogas, and the production of less toxic siloxane-based derivatives in the liquid phase. This study suggests that microaeration of the anaerobic sludge can significantly decrease the concentration of PDMSs in the WWTP effluent. However, for WWTPs to become effective barriers for the emission of these ecotoxic contaminants to the environment, such a strategy needs to be coupled with an efficient biodegradation of VOSiCs from the biogas.

Double-balloon enteroscopy: Experience with an innovative endoscopic technique at the Hospital Universitario de la Fundación Santa Fe de Bogotá. / Enteroscopia de doble balón: experiencia de una técnica endoscópica innovadora en el Hospital Universitario de la Fundación Santa Fe de Bogotá.

INTRODUCTION AND AIMS: Double-balloon enteroscopy is a recently introduced endoscopic method that enables complete visualization of the small bowel, as well as biopsy sampling and therapeutic interventions in that part of the intestine. The aim of the present study was to describe the experience acquired at our hospital to determine the characteristics of the patients that underwent the procedure. MATERIALS AND METHODS: A descriptive, cross-sectional study was conducted on all patients above 18 years of age admitted to the Hospital Universitario de la Fundación Santa Fe de Bogotá for double-balloon enteroscopy, within the time frame of January 2013 to December 2017. RESULTS: The study sample included 93 procedures in 73 patients. Mean patient age was 57.91 years, with a similar number of men and women. There were no severe complications. The most frequent indication for the enteroscopy was gastrointestinal bleeding (overt or occult), presenting in 49.46% of the patients, followed by chronic diarrhea (16.13%). Video capsule endoscopy was the previous study most frequently performed (53.76%). Anterograde double-balloon enteroscopy was carried out in 49 patients and 44 patients underwent the retrograde procedure. A total of 86.02% of the enteroscopies were diagnostic procedures and 13.98% were therapeutic. Normal enteroscopy was the most frequent finding (59.68%), followed by the presence of ulcers (15.05%). CONCLUSIONS: Our results were similar to those reported worldwide, with respect to indications, insertion route, and insertion depth, and there were no severe complications.

Jackhammer esophagus: Prevalence and demographic, clinical, and manometric characteristics. / «Jackhammer esophagus¼ (esófago en martillo hidráulico): prevalencia, características demográficas, clínicas y manométricas.

INTRODUCTION AND AIMS: Jackhammer esophagus is a recently identified motility disorder. Experience with the novel pathologic condition has been reported in different studies but there is little information on the subject in Latin America. Our case series conducted in Bogota, Colombia, describes the prevalence of jackhammer esophagus and its demographic, clinical, and manometric characteristics. MATERIALS AND METHODS: A retrospective, observational, cross-sectional study included consecutive patients diagnosed with jackhammer esophagus that were referred for high-resolution esophageal manometry. Their clinical and manometric records were reviewed, and the pertinent information for the present study was collected. RESULTS: Within the study period, 6,445 patients were evaluated with esophageal manometry, 27 of whom were diagnosed with jackhammer esophagus (prevalence of 0.42%). The majority of those patients were women (n=17, 63%) in the sixth decade of life. The most common symptom was regurgitation (n=17, 63%), followed by dysphagia (n=15, 56%). The mean distal contractile integral was 9,384 (5,095-18,546) mmHg·s·cm. Dysphagia was more common in patients >60 years of age (79%, p <.01) and regurgitation was more frequent in patients <60 years of age (92%, p <.03). CONCLUSIONS: The present study is the first to characterize the prevalence of jackhammer esophagus and its demographic, clinical, and manometric characteristics in Latin American patients. The prevalence of jackhammer esophagus in our study population was considerably lower than that reported in international case series. Our findings suggest that there are important geographic differences in the epidemiology and clinical presentation of jackhammer esophagus, compared with data from other international centers.

Nature and Distribution of Cu and Pd Species in CuPd/TiO2-Na Bimetallic Catalysts for Glycerol Hydrodeoxygenation.

We demonstrated recently that CuPd/TiO2-Na bimetallic catalysts synthesized by sequential wet impregnation are active, selective, and stable for the hydrodeoxygenation (HDO) of glycerol into propylene glycol at low H2 pressure. The present study reports on the nature and distribution of Cu and Pd surface species in CuPd/TiO2-Na bimetallic catalysts using different scanning transmission electron microscopy techniques that supply cluster-specific alloying details. In particular, we used atomic-resolution Z-contrast imaging, X-ray energy-dispersive spectroscopy, and electron energy-loss spectroscopy. We also include X-ray photoelectron spectroscopy results. Our analysis shows that the metallic nanoparticles adopt mainly five different structures according to how the Cu and Pd atoms coordinate among themselves: a homogeneous CuPd alloy structure (45-61%), a Cu shell/CuPd core (15-23%), a smaller number of particles formed by Cu on the surface and Pd in the nucleus (10-17%), and there are also nanoparticles formed only by Pd (4-7%) or by Cu (8-13%). We determined that there is a inhomogeneous distribution of Cu and Pd in the bimetallic nanoparticles, with Cu being predominant on the surface (between 76 and 90% of the total area analyzed for each particle). Most bimetallic nanoparticles have sizes below 6 nm, the Pd monometallic nanoparticles are in the 2-4 nm range, whereas the monometallic Cu nanoparticles are larger than 8 nm. Bimetallic nanoparticles with sizes smaller than 6-7 nm are fundamentally made up of Cu0-Pd0 and Cu1+-Pd0. The nanoparticles with sizes greater than 7 nm consist of Cu2+ and Cu2+-Pd2+. Our obtained results also help describe reports about the activation of HDO by Pd-Cu in the absence of H2, an effect apparently not observed with other bimetallic systems.

[The origins of language: an analysis from the aphasia perspective]. / Orígenes del lenguaje: un análisis desde la perspectiva de las afasias.

INTRODUCTION: Different areas of knowledge have contributed to a better understanding of the origins of human language. AIM. To relate our current knowledge about the origins of language with the language pathology found in the case of brain injuries (aphasia). DEVELOPMENT: There are two fundamental forms of aphasia, which linked to defects in the lexico-semantic and grammatical systems of language (Wernicke-type aphasia and Broca-type aphasia, respectively). From observations made on children's development of language and experiments with primates, it has been shown that language initially appears as a lexico-semantic system. Grammar correlates with the ability to represent actions (verbs) and depends on what is known as Broca's area and its related brain circuits, but it is also related to the ability to quickly carry out the sequencing of the articulatory movements required for speaking (speech praxis). CONCLUSIONS: Language may have appeared as a lexico-semantic system much earlier than language as a syntactic system. The former may have developed around 200,000-300,000 years ago, coinciding with the increase in the temporal lobe, and would have existed in other hominids. Language as a grammatical system appeared perhaps as recently as 50,000 years ago and seems to be exclusive to Homo sapiens.

[Neuropsychological predictors of reading ability in Spanish]. / Predictores neuropsicológicos de la lectura en español.

INTRODUCTION: Learning how to read has been associated with different types of linguistic and non-linguistic skills. However, few studies have looked at the association between neuropsychological test performance and reading skills at different ages during childhood. AIM: To analyze the association between neuropsychological test scores and reading performance, and to investigate the influence of age, gender and type of school (public or private) over reading test performance. SUBJECTS AND METHODS: The sample included 625 6 -to-15 year old children (207 Colombians, 418 Mexicans; 277 boys, 348 girls). The following cognitive abilities were assessed: reading speed and reading comprehension and attention, memory (coding and recall), perception, visuospatial and conceptual abilities and executive functions. RESULTS: The best neuropsychological test predictor for reading speed was Letter Cancellation, and for reading comprehension was Memory for a Story. Children from private schools performed better in most reading tests than children from public schools. Differences between boys and girls were observed in only two reading tests. CONCLUSION: Reading speed correlates mainly with attentional skills and reading comprehension with verbal memory. Reading abilities in school age children are influenced mainly by age and type of school and little by gender.

[Semantic verbal fluency in Spanish-speaking people: a comparative analysis]. / Fluidez verbal semántica en hispanohablantes: un análisis comparativo.

INTRODUCTION: Semantic verbal fluency (SVF) is the most commonly used test in the evaluation of normal and pathological functioning, whether it be clinically or experimentally. Several studies have suggested that the age, schooling and culture of the subject all affect performance in this test. To date no research has been conducted that proves whether there are differences between subjects who speak the same language but who come from different countries. PATIENTS AND METHODS: Data from the 'animals' category of the SVF in adult Spanish-speaking subjects and also the influence exerted by culture, age and schooling on the outcomes in this test were both submitted to analysis. The aforementioned variables were compared with the data reported by five research groups. RESULTS: The SVF test yields similar data from one Spanish-speaking country to another, provided that the subjects' age and schooling are taken into account. The differences found in this study may be due to variations in the way the tests are administered and scored rather than any cultural effect. We propose a standardised method of applying the test, so as to allow these variables to be unified in the future. CONCLUSION: Age and schooling are factors that determine performance in the SVF, although this is not true of culture.

Presenilin-1-associated abnormalities in regional cerebral perfusion.

OBJECTIVE: To investigate the influence of the presenilin-1 gene (PS-1) mutation on regional cerebral perfusion, SPECT was evaluated in 57 individuals. The subjects were members of a large pedigree from Colombia, South America, many of whom carry a PS-1 mutation for early-onset AD. METHODS: Members of this large kindred who were cognitively normal and did not carry the PS-1 mutation (n = 23) were compared with subjects who were carriers of the mutation but were asymptomatic (n = 18) and with individuals with the mutation and a clinical diagnosis of AD (n = 16). Cerebral perfusion was measured in each subject using hexamethylpropyleneamine oxime SPECT. The data were analyzed in two ways: 1) Mean cerebral perfusion in each of 4320 voxels in the brain was compared among the groups using t-tests (t-maps); and 2) each individual received a weighted score on 20 vectors (factors), based on a large normative sample (n = 200), using a method known as singular value decomposition (SVD). RESULTS: Based on t-maps, subjects with the PS-1 mutation who were asymptomatic demonstrated reduced perfusion in comparison with the normal control subjects in the hippocampal complex, anterior and posterior cingulate, posterior parietal lobe, and anterior frontal lobe. The AD patients demonstrated decreased perfusion in the posterior parietal and superior frontal cortex in comparison with the normal control subjects. Discriminant function analysis of the vector scores derived from SVD (adjusted for age and gender) accurately discriminated 86% of the subjects in the three groups (p < 0.0005). CONCLUSION: Regional cerebral perfusion abnormalities based on SPECT are detectable before development of the clinical symptoms of AD in carriers of the PS-1 mutation.

Calculation deficits in patients with right and left hemisphere damage.

Calculation abilities were studied in 41 left and 21 right hemisphere damaged patients. Their results were compared with a normal group matched by age, sex and educational level. Left hemisphere patients were grouped according to the type of accompanying aphasia. All patient groups presented at least a certain degree of acalculia. However, maximum difficulties were found in retrorolandic left hemisphere patients. Right hemisphere patients, especially retrorolandic patients, also presented impairments in calculation abilities, resulting mainly from spatial defects. Different types of errors were analyzed. Observed errors may be similar, but due to highly different neuropsychological dysfunctioning. Primary and secondary observed defects may be attributed to a diverse array of underlying deficits.

Handedness in native Amazonians.

A sample of 65 Tucano adolescents living in the Amazon region of Colombia were administered a 26-item handedness questionnaire. All subjects were right-handed. A factor analysis of the data indicated a factor structure rather different from that seen in North Americans, although both skilled and unskilled handedness factors were seen. Other factors related to specific tool use and to strength. These data indicate that positive reinforcement for right-hand use can modify patterns of handedness, and may well alter the relations among different items. The data suggest that hand preference can be modified through positive reinforcement at an appropriate age, and that hand preference is the precursor of skill differences rather than vice versa.

Effects of cultural background and education on handedness.

A 5-item handedness questionnaire was given to 317 subjects in four different groups: (1) 51 Tucano (Amazonian jungle) adolescents (36 male, 15 female); (2) 66 Spanish-speaking adolescents (43 male, 23 female) with similar age and educational background to the Tucano group; (3) 100 urban subjects (50 male, 50 female) with a low educational level; and (4) 100 urban subjects (50 male, 50 female) with a high level of education. Hand preference scores were not affected by sex or educational level. The incidence of left-handedness was lower in the Tucano group than in the other groups, despite the fact that the Tucano culture is a highly permissive one. The two rural groups showed less extreme hand preferences than the urban groups, and the Tucano in particular were less likely to indicate extreme hand preferences on any of the items. These results indicate significant effects of culture and environment on declared hand preference, and may be pertinent to recent discussions of cerebral organization in illiterates.

Neuropsychological test scores, academic performance, and developmental disorders in Spanish-speaking children.

Limited information is currently available about performance of Spanish-speaking children on different neuropsychological tests. This study was designed to (a) analyze the effects of age and sex on different neuropsychological test scores of a randomly selected sample of Spanish-speaking children, (b) analyze the value of neuropsychological test scores for predicting school performance, and (c) describe the neuropsychological profile of Spanish-speaking children with learning disabilities (LD). Two hundred ninety (141 boys, 149 girls) 6- to 11-year-old children were selected from a school in Bogotá, Colombia. Three age groups were distinguished: 6- to 7-, 8- to 9-, and 10- to 11-year-olds. Performance was measured utilizing the following neuropsychological tests: Seashore Rhythm Test, Finger Tapping Test (FTT), Grooved Pegboard Test, Children's Category Test (CCT), California Verbal Learning Test-Children's Version (CVLT-C), Benton Visual Retention Test (BVRT), and Bateria Woodcock Psicoeducativa en Español (Woodcock, 1982). Normative scores were calculated. Age effect was significant for most of the test scores. A significant sex effect was observed for 3 test scores. Intercorrelations were performed between neuropsychological test scores and academic areas (science, mathematics, Spanish, social studies, and music). In a post hoc analysis, children presenting very low scores on the reading, writing, and arithmetic achievement scales of the Woodcock battery were identified in the sample, and their neuropsychological test scores were compared with a matched normal group. Finally, a comparison was made between Colombian and American norms.

The future of neuropsychology with Hispanic populations in the United States.

This article discusses neuropsychology within the Spanish-speaking world; it reviews its recent history, existing efforts, and future directions. It also addresses the practice of neuropsychology with Hispanics in the United States and posits that it should take into account the heterogeneity of this population (the largest minority group in the country). Hispanic heterogeneity includes, among other variables, ethnicity, language, acculturation, age and education. Data from current research suggest that these are relevant variables affecting the psychometrics of cognition and therefore, the practice of neuropsychology with this population. Suggestions for future research are also addressed.

Correlation between intelligence test scores and executive function measures.

In this study, some executive function measures (Wisconsin Card Sorting Test [WCST], verbal fluency, and Trial Making Test [TMT], Form A and Form B) were correlated with Wechsler Intelligence Scale for Children-Revised (WISC-R) scores. Fifty 13- to 16-year-old normal children were selected. It was found that verbal fluency tests correlated about 0.30 with Verbal Intelligence Quotient (IQ) and Full Scale IQ. In the WCST only Perseverative Errors negatively correlated with Verbal IQ and Full Scale IQ. Two correlations were found to be significant with regard to the TMT: TMT Form B Errors negatively correlated with WISC-R Vocabulary subtest; and TMT Form A Time negatively correlated with Performance IQ. These results support the assumption that traditional intelligence tests are not appropriately evaluating executive functions.

Age-related cognitive decline during normal aging: the complex effect of education.

The purpose of this study was to further analyze the effects of education on cognitive decline during normal aging. An 806-subject sample was taken from five different Mexican regions. Participants ranged in age from 16 to 85 years. Subjects were grouped into four educational levels: illiterate, 1-4, 5-9, and 10 or more years of education, and four age ranges: 16-30, 31-50, 51-65, and 66-85 years. A brief neuropsychological test battery (NEUROPSI), standardized and normalized in Spanish, was administered. The NEUROPSI test battery includes assessment of orientation, attention, memory, language, visuoperceptual abilities, motor skills, and executive functions. In general, test scores were strongly associated with level of educational, and differences among age groups were smaller than differences among education groups. However, there was an interaction between age and education such as that among illiterate individuals scores of participants 31-50 years old were higher than scores of participants 16-30 years old for over 50% of the tests. Different patterns of interaction among educational groups were distinguished. It was concluded that: (a) The course of life-span changes in cognition are affected by education. Among individuals with a low level of education, best neuropsychological test performance is observed at an older age than among higher-educated subjects; and (b) there is not a single relationship between age-related cognitive decline and education, but different patterns may be found, depending upon the specific cognitive domain.