Asociación entre antropometría materna y peso del neonato a término. Cienfuegos, 2020-2021

Fundamento los indicadores antropométricos maternos constituyen una herramienta útil en el pronóstico de posibles resultados desfavorables en relación con la evaluación nutricional del producto de la concepción. Objetivo determinar la relación existente entre el estado nutricional antropométrico materno y el peso del recién nacido a término. Métodos se realizó un estudio descriptivo en 66 embarazadas y sus recién nacidos, en el periodo enero de 2020- diciembre de 2021, en el Policlínico Octavio de la Concepción y de la Pedraja, de Cienfuegos. Se consideraron las variables maternas: edad, peso, talla, índice de masa corporal gestacional, ganancia de peso global y circunferencia media del brazo; además del peso del recién nacido. Se calcularon estadísticos descriptivos básicos y coeficiente de correlación de Pearson. Resultados predominaron las adolescentes (n=42), la desnutrición materna (n=32), la ganancia deficiente de peso global y las gestantes evaluadas como bajo peso por los valores de la circunferencia media del brazo. El peso materno deficiente se asoció con 57,1 % y 20,8 % de recién nacidos bajo peso de madres adolescentes y adultas respectivamente. Estas variables mostraron asociación con el nacimiento de recién nacido bajo peso o con peso insuficiente. Conclusiones existe relación entre el estado nutricional antropométrico materno y el peso del neonato a término. Las variables maternas más asociadas al nacimiento de niños bajo peso o con peso insuficiente fueron: edad inferior a los 19 años, índice de masa corporal deficiente, escasa ganancia de peso global y valores de la circunferencia media del brazo > 5 y ≤ 10 percentil.

SUMMARY Background maternal anthropometric indicators constitute a useful tool in the prognosis of possible unfavorable results in relation to the product of conception nutritional evaluation. Objective to determine the relationship between the maternal anthropometric nutritional status and the newborn at term weight. Methods a descriptive study was carried out in 66 pregnant women and their newborns, from January 2020 to December 2021, at the Octavio de la Concepción y de la Pedraja Polyclinic, in Cienfuegos. Maternal variables: age, weight, height, gestational body mass index, overall weight gain, and mean arm circumference; in addition to the weight of the newborn were considered. Basic descriptive statistics and Pearson's correlation coefficient were calculated. Results adolescents (n=42), maternal malnutrition (n=32), deficient global weight gain and pregnant women evaluated as low weight by the values of the mean arm circumference predominated. Low maternal weight was associated with 57.1% and 20.8% of low birth weight newborns of adolescent and adult mothers, respectively. These variables showed an association with the birth of a newborn underweight or with insufficient weight. Conclusions there is a relationship between the maternal anthropometric nutritional status and the newborn at term weight. The maternal variables most associated with the underweight birth were: age less than 19 years, poor body mass index, low overall weight gain, and mean arm circumference values > 5 and ≤ 10 percentile.

Integrating gene annotation with orthology inference at scale.

Annotating coding genes and inferring orthologs are two classical challenges in genomics and evolutionary biology that have traditionally been approached separately, limiting scalability. We present TOGA (Tool to infer Orthologs from Genome Alignments), a method that integrates structural gene annotation and orthology inference. TOGA implements a different paradigm to infer orthologous loci, improves ortholog detection and annotation of conserved genes compared with state-of-the-art methods, and handles even highly fragmented assemblies. TOGA scales to hundreds of genomes, which we demonstrate by applying it to 488 placental mammal and 501 bird assemblies, creating the largest comparative gene resources so far. Additionally, TOGA detects gene losses, enables selection screens, and automatically provides a superior measure of mammalian genome quality. TOGA is a powerful and scalable method to annotate and compare genes in the genomic era.

Bat pluripotent stem cells reveal unusual entanglement between host and viruses.

Bats are distinctive among mammals due to their ability to fly, use laryngeal echolocation, and tolerate viruses. However, there are currently no reliable cellular models for studying bat biology or their response to viral infections. Here, we created induced pluripotent stem cells (iPSCs) from two species of bats: the wild greater horseshoe bat (Rhinolophus ferrumequinum) and the greater mouse-eared bat (Myotis myotis). The iPSCs from both bat species showed similar characteristics and had a gene expression profile resembling that of cells attacked by viruses. They also had a high number of endogenous viral sequences, particularly retroviruses. These results suggest that bats have evolved mechanisms to tolerate a large load of viral sequences and may have a more intertwined relationship with viruses than previously thought. Further study of bat iPSCs and their differentiated progeny will provide insights into bat biology, virus host relationships, and the molecular basis of bats' special traits.

The pale spear-nosed bat: A neuromolecular and transgenic model for vocal learning.

Vocal learning, the ability to produce modified vocalizations via learning from acoustic signals, is a key trait in the evolution of speech. While extensively studied in songbirds, mammalian models for vocal learning are rare. Bats present a promising study system given their gregarious natures, small size, and the ability of some species to be maintained in captive colonies. We utilize the pale spear-nosed bat (Phyllostomus discolor) and report advances in establishing this species as a tractable model for understanding vocal learning. We have taken an interdisciplinary approach, aiming to provide an integrated understanding across genomics (Part I), neurobiology (Part II), and transgenics (Part III). In Part I, we generated new, high-quality genome annotations of coding genes and noncoding microRNAs to facilitate functional and evolutionary studies. In Part II, we traced connections between auditory-related brain regions and reported neuroimaging to explore the structure of the brain and gene expression patterns to highlight brain regions. In Part III, we created the first successful transgenic bats by manipulating the expression of FoxP2, a speech-related gene. These interdisciplinary approaches are facilitating a mechanistic and evolutionary understanding of mammalian vocal learning and can also contribute to other areas of investigation that utilize P. discolor or bats as study species.

Gene losses in the common vampire bat illuminate molecular adaptations to blood feeding.

Vampire bats are the only mammals that feed exclusively on blood. To uncover genomic changes associated with this dietary adaptation, we generated a haplotype-resolved genome of the common vampire bat and screened 27 bat species for genes that were specifically lost in the vampire bat lineage. We found previously unknown gene losses that relate to reduced insulin secretion (FFAR1 and SLC30A8), limited glycogen stores (PPP1R3E), and a unique gastric physiology (CTSE). Other gene losses likely reflect the biased nutrient composition (ERN2 and CTRL) and distinct pathogen diversity of blood (RNASE7) and predict the complete lack of cone-based vision in these strictly nocturnal bats (PDE6H and PDE6C). Notably, REP15 loss likely helped vampire bats adapt to high dietary iron levels by enhancing iron excretion, and the loss of CYP39A1 could have contributed to their exceptional cognitive abilities. These findings enhance our understanding of vampire bat biology and the genomic underpinnings of adaptations to blood feeding.

High phylogeographic and genetic diversity of Tidestromia lanuginosa supports full-glacial refugia for arid-adapted plants in southern and central Coahuila, Mexico.

PREMISE: Recent phylogeographic work suggests the existence of latitudinal gradients in genetic diversity in northern Mexican plants, but very few studies have examined plants of the Chihuahuan Desert. Tidestromia lanuginosa is a morphologically variable annual species whose distribution includes the Chihuahuan Desert Region. Here we undertook phylogeographic analyses of chloroplast loci in this species to test whether genetic diversity and differentiation of Mexican populations of T. lanuginosa change along a latitudinal gradient and whether diversity is higher in Coahuila, consistent with ideas of lower plant community turnover during the Pleistocene. METHODS: Haplotype network, maximum likelihood tree, and Bayesian phylogenetic haplotype were reconstructed, and genetic diversity was assessed among 26 populations. Barrier analysis was used to explore barriers to gene flow. RESULTS: Four major population groups were identified, corresponding with physiographic provinces in Mexico. Each population group displayed high levels of genetic structure, haplotype, and nucleotide diversity. Diversity was highest in southern populations across the species as a whole and among the Chihuahuan Desert populations. CONCLUSIONS: Tidestromia lanuginosa provides an important example of high phylogeographic and genetic diversity in plants of northern Mexico. Barriers to gene flow among the major population groups have most likely been due to a combination of orographic, climatic, and edaphic variables. The high genetic diversity of T. lanuginosa in southern and central Coahuila is consistent with the hypothesis of full-glacial refugia for arid-adapted plants in this area, and highlights the importance of this region as a center of diversity for the Chihuahuan Desert flora.

Phylogeography, Population Structure, and Species Delimitation in Rockhopper Penguins (Eudyptes chrysocome and Eudyptes moseleyi).

Rockhopper penguins are delimited as 2 species, the northern rockhopper (Eudyptes moseleyi) and the southern rockhopper (Eudyptes chrysocome), with the latter comprising 2 subspecies, the western rockhopper (Eudyptes chrysocome chrysocome) and the eastern rockhopper (Eudyptes chrysocome filholi). We conducted a phylogeographic study using multilocus data from 114 individuals sampled across 12 colonies from the entire range of the northern/southern rockhopper complex to assess potential population structure, gene flow, and species limits. Bayesian and likelihood methods with nuclear and mitochondrial DNA, including model testing and heuristic approaches, support E. moseleyi and E. chrysocome as distinct species lineages with a divergence time of 0.97 Ma. However, these analyses also indicated the presence of gene flow between these species. Among southern rockhopper subspecies, we found evidence of significant gene flow and heuristic approaches to species delimitation based on the genealogical diversity index failed to delimit them as species. The best-supported population models for the southern rockhoppers were those where E. c. chrysocome and E. c. filholi were combined into a single lineage or 2 lineages with bidirectional gene flow. Additionally, we found that E. c. filholi has the highest effective population size while E. c. chrysocome showed similar effective population size to that of the endangered E. moseleyi. We suggest that the current taxonomic definitions within rockhopper penguins be upheld and that E. chrysocome populations, all found south of the subtropical front, should be treated as a single taxon with distinct management units for E. c. chrysocome and E. c. filholi.

Diversification rates have no effect on the convergent evolution of foraging strategies in the most speciose genus of bats, Myotis.

Adaptive radiations are defined as rapid diversification with phenotypic innovation led by colonization to new environments. Notably, adaptive radiations can occur in parallel when habitats with similar selective pressures are accessible promoting convergent adaptions. Although convergent evolution appears to be a common process, it is unclear what are the main drivers leading the reappearance of morphologies or ecological roles. We explore this question in Myotis bats, the only Chiropteran genus with a worldwide distribution. Three foraging strategies-gleaning, trawling, and aerial netting-repeatedly evolved in several regions of the world, each linked to characteristic morphologies recognized as ecomorphs. Phylogenomic, morphometric, and comparative approaches were adopted to investigate convergence of such foraging strategies and skull morphology as well as factors that explain diversification rates. Genomic and morphometric data were analyzed from ∼80% extant taxa. Results confirm that the ecomorphs evolved multiple times, with trawling evolving more often and foliage gleaning most recently. Skull morphology does not reflect common ancestry and evolves convergently with foraging strategy. Although diversification rates have been roughly constant across the genus, speciation rates are area-dependent and higher in taxa with temperate distributions. Results suggest that in this species-rich group of bats, first, stochastic processes have led divergence into multiple lineages. Then, natural selection in similar niches has promoted repeated adaptation of phenotypes and foraging strategies. Myotis bats are thus a remarkable case of ecomorphological convergence and an emerging model system for investigating the genomic basis of parallel adaptive radiation.

Genome-specific histories of divergence and introgression between an allopolyploid unisexual salamander lineage and two ancestral sexual species.

Quantifying introgression between sexual species and polyploid lineages traditionally thought to be asexual is an important step in understanding what drives the longevity of putatively asexual groups. Here, we capitalize on three recent innovations-ultraconserved element (UCE) sequencing, bioinformatic techniques for identifying genome-specific variation in polyploids, and model-based methods for evaluating historical gene flow-to measure the extent and tempo of introgression over the evolutionary history of an allopolyploid lineage of all-female salamanders and two ancestral sexual species. Our analyses support a scenario in which the genomes sampled in unisexual salamanders last shared a common ancestor with genomes in their parental species ∼3.4 million years ago, followed by a period of divergence between homologous genomes. Recently, secondary introgression has occurred at different times with each sexual species during the last 500,000 years. Sustained introgression of sexual genomes into the unisexual lineage is the defining characteristic of their reproductive mode, but this study provides the first evidence that unisexual genomes have undergone long periods of divergence without introgression. Unlike other sperm-dependent taxa in which introgression is rare, the alternating periods of divergence and introgression between unisexual salamanders and their sexual relatives could explain why these salamanders are among the oldest described unisexual animals.

Evidence that Myotis lucifugus "Subspecies" are Five Nonsister Species, Despite Gene Flow.

While genetic exchange between nonsister species was traditionally considered to be rare in mammals, analyses of molecular data in multiple systems suggest that it may be common. Interspecific gene flow, if present, is problematic for phylogenetic inference, particularly for analyses near the species level. Here, we explore how to detect and account for gene flow during phylogeny estimation using data from a clade of North American Myotis bats where previous results have led researchers to suspect that gene flow among lineages is present. Initial estimates of phylogenetic networks and species trees indicate that subspecies described within Myotis lucifugus are paraphyletic. In order to explore the extent to which gene flow is likely to interfere with phylogeny estimation, we use posterior predictive simulation and a novel Approximate Bayesian Computation approach based on gene tree distances. The former indicates that the species tree model is a poor fit to the data, and the latter provides evidence that a species tree with gene flow is a better fit. Taken together, we present evidence that the currently recognized M. lucifugus subspecies are paraphyletic, exchange alleles with other Myotis species in regions of secondary contact, and should be considered independent evolutionary lineages despite their morphological similarity.

Objective choice of phylogeographic models.

Phylogeography seeks to discover the evolutionary processes that have given rise to organismal and genetic diversity. This requires explicit hypotheses (i.e., models) to be evaluated with genetic data in order to identify those hypotheses that best explain the data. In recent years, advancements in the model-based tools used to estimate phylogeographic parameters of interest such as gene flow, divergence time, and relationships among groups have been made. However, given the complexity of these models, available methods can typically only compare a handful of possible hypotheses, requiring researchers to specify in advance the small set of models to consider. Without formal quantitative approaches to model selection, researchers must rely on their intuition to formulate the model space to be explored. We explore the adequacy of intuitive choices made by researchers during the process of data analysis by reanalyzing 20 empirical phylogeographic datasets using PHRAPL, an objective tool for phylogeographic model selection. We show that the best models for most datasets include both gene flow and population divergence parameters, and that species tree methods (which do not consider gene flow) tend to be overly simplistic for many phylogeographic systems. Objective approaches to phylogeographic model selection offer an important complement to researcher intuition.

PHRAPL: Phylogeographic Inference Using Approximate Likelihoods.

The demographic history of most species is complex, with multiple evolutionary processes combining to shape the observed patterns of genetic diversity. To infer this history, the discipline of phylogeography has (to date) used models that simplify the historical demography of the focal organism, for example by assuming or ignoring ongoing gene flow between populations or by requiring a priori specification of divergence history. Since no single model incorporates every possible evolutionary process, researchers rely on intuition to choose the models that they use to analyze their data. Here, we describe an approximate likelihood approach that reduces this reliance on intuition. PHRAPL allows users to calculate the probability of a large number of complex demographic histories given a set of gene trees, enabling them to identify the most likely underlying model and estimate parameters for a given system. Available model parameters include coalescence time among populations or species, gene flow, and population size. We describe the method and test its performance in model selection and parameter estimation using simulated data. We also compare model probabilities estimated using our approximate likelihood method to those obtained using standard analytical likelihood. The method performs well under a wide range of scenarios, although this is sometimes contingent on sampling many loci. In most scenarios, as long as there are enough loci and if divergence among populations is sufficiently deep, PHRAPL can return the true model in nearly all simulated replicates. Parameter estimates from the method are also generally accurate in most cases. PHRAPL is a valuable new method for phylogeographic model selection and will be particularly useful as a tool to more extensively explore demographic model space than is typically done or to estimate parameters for complex models that are not readily implemented using current methods. Estimating relevant parameters using the most appropriate demographic model can help to sharpen our understanding of the evolutionary processes giving rise to phylogeographic patterns. [AIC; grid search; isolation-with-migration; migration rate; multispecies coalescent; parameter optimization; population genetics; tree topologies.].

Species Delimitation with Gene Flow.

Species are commonly thought to be evolutionarily independent in a way that populations within a species are not. In recent years, studies that seek to identify evolutionarily independent lineages (i.e., to delimit species) using genetic data have typically adopted multispecies coalescent approaches that assume that evolutionary independence is formed by the differential sorting of ancestral alleles due to genetic drift. However, gene flow appears to be common among populations and nascent species, and while this process may inhibit lineage divergence (and thus independence), it is usually not explicitly considered when delimiting species. In this article, we apply Phylogeographic Inference using Approximate Likelihoods (PHRAPL), a recently described method for phylogeographic model selection, to species delimitation. We describe an approach to delimiting species using PHRAPL that attempts to account for both genetic drift and gene flow, and we compare the method's performance to that of a popular delimitation approach (BPP) using both simulated and empirical datasets. PHRAPL generally infers the correct demographic-delimitation model when the generating model includes gene flow between taxa, given a sufficient amount of data. When the generating model includes only isolation in the recent past, PHRAPL will in some cases fail to differentiate between gene flow and divergence, leading to model misspecification. Nevertheless, the explicit consideration of gene flow by PHRAPL is an important complement to existing delimitation approaches, particularly in systems where gene flow is likely important. [approximate likelihoods; coalescent simulations; genealogical divergence index; Homo sapiens; isolation-with-migration; multispecies coalescent; Sarracenia; Scincella.].

Speciation with Gene Flow in North American Myotis Bats.

Growing evidence supports the idea that species can diverge in the presence of gene flow. However, most methods of phylogeny estimation do not consider this process, despite the fact that ignoring gene flow is known to bias phylogenetic inference. Furthermore, studies that do consider divergence-with-gene-flow typically do so by estimating rates of gene flow using a isolation-with-migration model (IM), rather than evaluating scenarios of gene flow (such as divergence-with-gene flow or secondary contact) that represent very different types of diversification. In this investigation, we aim to infer the recent phylogenetic history of a clade of western long-eared bats while evaluating a number of different models that parameterize gene flow in a variety of ways. We utilize PHRAPL, a new tool for phylogeographic model selection, to compare the fit of a broad set of demographic models that include divergence, migration, or both among Myotis evotis, $M$. thysanodes and M. keenii. A genomic data set consisting of 808 loci of ultraconserved elements was used to explore such models in three steps using an incremental design where each successive set was informed by, and thus more focused than, the previous set of models. Specifically, the three steps were to (i) assess whether gene flow should be modeled and identify the best topologies, (ii) infer directionality of migration using the best topologies, and (iii) estimate the timing of gene flow. The best model (AIC model weight ${\sim}0.98$) included two divergence events (($M$. evotis, $M$. thysanodes), M. keenii) accompanied by gene flow at the initial stages of divergence. These results provide a striking example of speciation-with-gene-flow in an evolutionary lineage. [Myotis bats; PHRAPL; P2C2M; phylogeographic model selection; speciation with gene flow.].

The evolution of phylogeographic data sets.

Empirical phylogeographic studies have progressively sampled greater numbers of loci over time, in part motivated by theoretical papers showing that estimates of key demographic parameters improve as the number of loci increases. Recently, next-generation sequencing has been applied to questions about organismal history, with the promise of revolutionizing the field. However, no systematic assessment of how phylogeographic data sets have changed over time with respect to overall size and information content has been performed. Here, we quantify the changing nature of these genetic data sets over the past 20 years, focusing on papers published in Molecular Ecology. We found that the number of independent loci, the total number of alleles sampled and the total number of single nucleotide polymorphisms (SNPs) per data set has improved over time, with particularly dramatic increases within the past 5 years. Interestingly, uniparentally inherited organellar markers (e.g. animal mitochondrial and plant chloroplast DNA) continue to represent an important component of phylogeographic data. Single-species studies (cf. comparative studies) that focus on vertebrates (particularly fish and to some extent, birds) represent the gold standard of phylogeographic data collection. Based on the current trajectory seen in our survey data, forecast modelling indicates that the median number of SNPs per data set for studies published by the end of the year 2016 may approach ~20,000. This survey provides baseline information for understanding the evolution of phylogeographic data sets and underscores the fact that development of analytical methods for handling very large genetic data sets will be critical for facilitating growth of the field.

[Effectiveness of two aerobic exercise programs in the treatment of metabolic syndrome: a preliminary study]. / Efectividad de dos modalidades de ejercicio aeróbico en el tratamiento de pacientes con síndrome metabólico (SM). Estudio preliminar.

The effectiveness of two aerobic exercise programs on the modification of the metabolic syndrome (MS) components and its influence in reducing cardiovascular risk was evaluated in 16 sedentary women (30-66 years old). Patients were randomly divided into two exercise groups: continuous training (CE: 45 minutes at 65-70% of heart rate reserve or HRR) or interval training (IE: 5 x 3 minute intervals at 80-85% HRR with two minutes of active recovery at 65-70% HRR), and each participant gave previous informed consent. The components of MS were assessed according to the criteria for women of the National Cholesterol Education/Third Treatment Adult Panel, and cardiovascular risk factors at baseline and 16 weeks later. Data analyses were performed with the Wilcoxon signed test and the Mann-Whitney U-test (SPSS v. 12.0 Windows: p < 0.05). Both exercise programs were effective in the modification of a number of MS components (triglycerides, systolic/diastolic blood pressure), however IE had a higher percentage of patients without MS diagnosis at the end of the study (62.5%). The CE improved the physical fitness by increasing the VO2peak and METs and decreasing heart rate recovery, which is reflected on the reduction of cardiovascular risk.

[Isokinetic evaluation of the muscular strength and balance of knee extensor and flexor apparatus of taekwondo athletes]. / Valoración isocinética de la fuerza y balance muscular del aparato extensor y flexor de la rodilla en taekwondoines.

UNLABELLED: Lower limb strength and muscular balance are important attributes in the practice of Taekwondo. OBJECTIVE: To assess through isokinetic dynamometry the muscular strength and balance of knee extensor and flexor apparatus of elite Taekwondo athletes and to compare with recreational-type athletes. METHODS: The maximum torque, the angle of maximum torque, maximum torque work, total work of the series, average power, and flexor and extensor muscle apparatus balance of the knees were obtained. RESULTS: A total of 32 knees were studied. Significantly higher values in peak torque and total work of the series were present in the group of TKD athletes in the extensor muscles, while the maximum torque angle of extensor and flexor muscles was higher in controls. We found a muscular imbalance due to flexor muscle strength deficit in both groups. CONCLUSIONS: Higher levels of muscular strength and an imbalance between the knee flexor and extensor muscle groups characterized the predominant motor gesture of TKD athletes. These results are useful in the design and implementation of training programs, to optimize the value of muscular strength and muscle balance in TKD athletes directed to promote optimal athletic performance and prevent sport-related injuries.

[Decrease of liver fat content by aerobic exercise or metformin therapy in overweight or obese women]. / Disminucion del contenido de grasa hepatica mediante ejercicio aerobico comparado con met formina en mujeres con sobrepeso u obesidad.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is characterized by high intrahepatic triglyceride level. It is associated with an increased prevalence of cardiovascular disease, independently of underlying cardiometabolic risk factors. Metformin is used as a pharmacological treatment; the adherence is low because of the presence of adverse effects. Aerobic exercise could be an alternative therapy, but its effectiveness compared with metformin has not been established in the treatment of NAFLD. The aim of this study was to establish the effectiveness of aerobic exercise and its influence in reducing cardiovascular risk in overweight or obese women with NAFLD. MATERIAL AND METHODS: Sedentary women 25-60 years old with body mass index (BMI) > 24.9 kg/m2 and liver fat content < 50 HU, were randomly divided into two parallel groups: exercise group (EG) or metformin group (MG). The EG performed an aerobic exercise program of 60 min/5 days/ week at 60-85% of heart rate reserve; the MG took 1 g/day of metformin each morning. The duration of the intervention was 12 weeks. The liver fat content, metabolic and cardiorespiratory- fitness parameters were evaluated at the beginning and end of the program. The study complied with the Helsinki ethics codes for human research. RESULTS: The study included a sample of 16 women, with 8 per group. The treatments modified the liver fat content by 14.6% (CI95% 0.92, 28.36) and 10.37% (CI95% -1.74, 22.48) for the EG and MG, respectively. In the EG, the insulin levels and HOMA-IR decreased (P < 0.05), and the cardiovascular fitness improved. CONCLUSIONS: An aerobic exercise program of 12 weeks with a volume training of 300 min/week and a moderate to vigorous intensity (60-85% VO2peak) modified the liver fat content and improved cardiovascular risk factors during the intervention. Exercise contributed to a holistic approach by modifying a number of the components of metabolic syndrome, cardiorespiratory-fitness, and cardiovascular risk.

Inactivation of Ascaris eggs in water using hydrogen peroxide and a Fenton type nanocatalyst (FeOx/C) synthesized by a novel hybrid production process.

Inactivation tests of Ascaris eggs (Ae) were performed using hydrogen peroxide and a Fenton type nanocatalyst supported on activated carbon (AC) (FeOx/C). Blank inactivation tests were also carried out using H2O2 and H2O2/AC as oxidation systems. The FeOx/C nanocatalyst was synthesized through a novel hybrid method developed in this work. The method is based on the incipient impregnation technique, using isopropyl alcohol as dissolvent and chelating agent of the iron salt and the ultrasonic method. The supported nanocatalyst contained 2.61% w/w of total iron and the support 0.2% w/w. Transmission electron microscopy (TEM)-energy dispersive spectrometer (EDS) images permitted verification of the presence of finely dispersed FeOx nanoparticles, with sizes ranging from 19 to 63 nm. SEM-EDS analysis and TEM images also showed good dispersion of iron oxide nanoparticles, most probably maghemite; γ-Fe2O3, able to produce hydroperoxyl radical as reported in the literature. The FeOx/C nanocatalyst-H2O2 system showed an average Ae inactivation efficiency of 4.46% Ae/mg H2O2. This value is significantly higher than the result obtained using the support-H2O2 system and H2O2 alone and it is also better than data reported for the classical Fenton process (homogeneous phase) with or without UV light.