Quenched lattice fluctuations in optically driven SrTiO3.

Crystal lattice fluctuations, which are known to influence phase transitions of quantum materials in equilibrium, are also expected to determine the dynamics of light-induced phase changes. However, they have only rarely been explored in these dynamical settings. Here we study the time evolution of lattice fluctuations in the quantum paraelectric SrTiO3, in which mid-infrared drives have been shown to induce a metastable ferroelectric state. Crucial in these physics is the competition between polar instabilities and antiferrodistortive rotations, which in equilibrium frustrate the formation of long-range ferroelectricity. We make use of high-intensity mid-infrared optical pulses to resonantly drive the Ti-O-stretching mode at 17 THz, and we measure the resulting change in lattice fluctuations using time-resolved X-ray diffuse scattering at a free-electron laser. After a prompt increase, we observe a long-lived quench in R-point antiferrodistortive lattice fluctuations. Their enhancement and reduction are theoretically explained by considering the fourth-order nonlinear phononic interactions to the driven optical phonon and third-order coupling to lattice strain, respectively. These observations provide a number of testable hypotheses for the physics of light-induced ferroelectricity.

A lifestyle adjustments program in long COVID-19 improves symptomatic severity and quality of life. A randomized control trial.

OBJECTIVE: To evaluate the efficacy of a therapeutic intervention based on self-adjustment strategies for improving of symptomatic severity and quality of life. METHODS: The study was a randomised single-blind clinical trial. Quality of life, disability, and functional impairment were collected. The control group received a leaflet with information on the main symptoms of Long-COVID-19 syndrome, in addition to standard medical treatment. The intervention group received treatment following a dual approach; on the one hand, monitoring and recognition of symptomatology and on the other hand, adaptation and functional improvement. RESULTS: A total of 54 participants were included, 27 were included in the intervention group and 27 in the control group. At the beginning of the study, no significant differences were found between groups. After intervention, the quality of life variable showed significant differences between groups in the self-care and anxiety/depression dimensions. Significant between-groups differences were also found for the self-care subscale of the disability variable. The intervention group showed significant differences from baseline on some subscales of the quality of life, disability, and functional impairment variables. CONCLUSION: Strategies based on lifestyle adjustments are adequate for the improvement of quality of life and symptom severity in the long COVID-19 population. PRACTICE IMPLICATION: The findings suggest that applying an intervention focused in self-adjustment for long COVID patients can have positive effects.

Water Pollution Increases the Risk of Chytridiomycosis in Mexican Amphibians.

Chytridiomycosis is affecting amphibians worldwide, causing the decline and extinction of several amphibian populations. The disease is caused by the fungus Batrachochytrium dendrobatidis (Bd), a multihost pathogen living in freshwater habitats. While several environmental factors have been associated with the prevalence of Bd and its virulence, the effects of water quality on the pathogen are not clear yet. Some evidence suggests that water pollution may reduce amphibians' immune response and increase prevalence of Bd. To explore this hypothesis, we analyzed the relationship between water quality and the presence of Bd by using spatial data mining of 150 geolocations of Bd in amphibians from 9 families where Bd positive specimens have been previously reported, and water quality in 4,202 lentic and lotic water bodies in Mexico from 2010 to 2021. Our model showed that in the 3 main families where Bd was recorded, its presence is high in locations with low water quality, i.e., water polluted likely contaminated with urban and industrial waste. Using this model, we inferred areas suitable for Bd in Mexico; mainly in poorly studied areas along the gulf and on the pacific slope. We further argue that actions to reduce water pollution should become an integral part of public policies to prevent the spread of Bd and protect amphibians from this deadly pathogen.

About the relationship of the processing conditions, mechanical properties, and microstructure of a co-precipitated Fe/Cu prealloyed powder.

The sinterability of a commercial Fe-Cu pre-alloyed powder, designed to be used as a metallic bond in diamond impregnated tools, has been greatly analyzed by combining dilatometry, computational thermodynamic calculations, and microstructural analysis. The effect of sintering temperature and alloying elements such as graphite and iron phosphide have been taken into consideration in order to demonstrate the capability of tailoring final properties through different strategies, and dilatometry and microstructural analysis have been used to understand the densification process of the alloys. Solid phase sintering was the mechanism taking place during thermal cycle. In fact, a liquid phase appears but because of the high densification level at that time mechanisms associated with LPS do not contribute to densification. Discussion about mechanical properties has been related to key microstructural phenomena, i.e., grain growth, phase transformation, precipitation, and solid solution. Obtained hardness ranged from 83 HRB to 106 HRB with yield stresses between 450 MPa and 700 MPa and elongations above 3%, while final tensile properties similar to those obtained by cobalt-based powders processed by hot pressing were also obtained.

Ultrafast Suppression of the Ferroelectric Instability in KTaO_{3}.

We use an x-ray free-electron laser to study the lattice dynamics following photoexcitation with ultrafast near-UV light (wavelength 266 nm, 50 fs pulse duration) of the incipient ferroelectric potassium tantalate, KTaO_{3}. By probing the lattice dynamics corresponding to multiple Brillouin zones through the x-ray diffuse scattering with pulses from the Linac Coherent Light Source (LCLS) (wavelength 1.3 Å and <10 fs pulse duration), we observe changes in the diffuse intensity associated with a hardening of the transverse acoustic phonon branches along Γ to X and Γ to M. Using force constants from density functional theory, we fit the quasiequilibrium intensity and obtain the instantaneous lattice temperature and density of photoexcited charge carriers. The density functional theory calculations demonstrate that photoexcitation transfers charge from oxygen 2p derived π-bonding orbitals to Ta 5d derived antibonding orbitals, further suppressing the ferroelectric instability and increasing the stability of the cubic, paraelectric structure.

Direct Observation of Coherent Longitudinal and Shear Acoustic Phonons in TaAs Using Ultrafast X-Ray Diffraction.

Using femtosecond time-resolved x-ray diffraction, we investigated optically excited coherent acoustic phonons in the Weyl semimetal TaAs. The low symmetry of the (112) surface probed in our experiment enables the simultaneous excitation of longitudinal and shear acoustic modes, whose dispersion closely matches our simulations. We observed an asymmetry in the spectral line shape of the longitudinal mode that is notably absent from the shear mode, suggesting a time-dependent frequency chirp that is likely driven by photoinduced carrier diffusion. We argue on the basis of symmetry that these acoustic deformations can transiently alter the electronic structure near the Weyl points and support this with model calculations. Our study underscores the benefit of using off-axis crystal orientations when optically exciting acoustic deformations in topological semimetals, allowing one to transiently change their crystal and electronic structures.

Reduction of Fusarium proliferatum growth and fumonisin accumulation by ZnO nanoparticles both on a maize based medium and irradiated maize grains.

This study evaluated the antifungal effect of ZnO nanoparticles (ZnO-NPs) on Fusarium proliferatum growth and fumonisin accumulation both on a maize-based medium (in vitro) and on irradiated maize grains (in situ). The ZnO-NPs were obtained by drop-by-drop synthesis without further thermal treatment and characterized by scanning electronic microscopy/ energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD). SEM analysis showed them as thin flakes of 200 × 200 nm, ~30 nm thickness and its purity were confirmed by XRD. During the in vitro assay ZnO-NPs (0, 0.8; 4, 8 g L-1) were evaluated at 25 °C during 21 days under darkness or photoperiod incubation (12/12 h light (cold white and black fluorescent lamps)/darkness) to determine its possible photocatalytic influence. Fumonisins were detected by high performance liquid chromatography coupled to mass spectrometry (HPLC- MS/MS). All ZnO-NPs concentrations significantly affected growth rates and FB1 accumulation by F. proliferatum RCFP 5033 (p < 0.05). Similar reduction of growth and FB1 (%) was observed at 0.8 and 8 g L-1 ZnO-NPs under photoperiod or darkness incubation. FB1 reduction was observed after 14 and 21 days, although the highest reduction occurred after 14 days under photoperiod incubation (84-98%). No clear light enhancing effect on the antifungal and anti-mycotoxin capability of the ZnO-NPs was observed. Morphological alterations in mycelia and conidia were observed by SEM. Under the in situ assay, the effect of the ZnO-NPs (0, 0.4, 0.8, 2 g kg-1) on growth rates and fumonisin B1, B2 and B3 accumulation by two F. proliferatum strains was evaluated on irradiated maize grains adjusted to 0.995, 0.98 and 0.97 aW in darkness at 25 °C during 21 days. Also, zinc acetate at 0.8 g kg-1 was included to compare their antifungal effect against the same ZnO-NPs concentration. Growth rates decreased significantly as ZnO-NPs concentrations increased. Higher than 60% of growth reduction was observed for both F. proliferatum strains. Zinc acetate significantly reduced growth, although it was less efficient that the same ZnO-NPs concentration. ZnO-NPs reduced total fumonisins accumulation by 71-99% at 0.8-2 g kg-1 ZnO-NPs and 0.98-0.995 aW. Moreover, 0.4 g kg-1 ZnO-NPs also produced significant reduction of the 3 fumonisins. This study showed the application of ZnO-NPs in maize grains could be a low cost and environmental impact strategy to control phytopathogen and toxigenic fungi such as F. proliferatum and to reduce fumonisins accumulation, both during crop development at preharvest stage and during maize storage.

Potassium reduction in food by preparation technique for the dietetic management of patients with chronic kidney disease: a review.

BACKGROUND: Chronic kidney disease patients often use food preparation techniques to reduce potassium intake. However, the most effective techniques have not yet been determined for all food groups. The present study aimed to analyse all of the available information on potassium reduction in the food and identify the best preparation techniques by comparing the trend of change in potassium level. METHODS: Nine databases were searched from 1976 to May 2020, according to the PRISMA Statement. We included all articles reporting the amount of potassium before and after the application of food preparation techniques. Data were analysed using the Wilcoxon test and statistical simulation. RESULTS: A wide variety of food and culinary processes was observed in the 65 included articles. Cooking in water, pressure cooking and cooking in a microwave oven reduced potassium levels in all food groups, particularly in cereals and derivatives, fruits and derivatives, meats and derivatives, legumes, and leafy and cruciferous vegetables. Soaking food significantly reduced the potassium content in tubers and roots and leafy and cruciferous vegetables. Steam cooking and dry heating cooking also reduced potassium, although at a level lower than the other techniques. CONCLUSIONS: The present review shows that, in general, all food preparation techniques can reduce the potassium content, although cooking in water and soaking promotes a greater reduction; however, more studies with standardised techniques and complete data are necessary.

Quantitative and Topographic Analysis by Immunohistochemical Expression of Ghrelin Gastric Cells in Patients with Morbid Obesity.

PURPOSE: The cellular distribution of ghrelin positive cells is not well defined. The aim of the study is to quantify and determine the distribution of ghrelin cells in gastric mucosa in patients with morbid obesity and relate this finding to gender, comorbidities, gastritis, and plasmatic levels of acyl and desacylghrelin before and after laparoscopic sleeve gastrectomy. PATIENT AND METHODS: We performed a study on 61 patients with BMI≥50 kg/m2 operated by laparoscopic sleeve gastrectomy. Three gastric regions were analyzed by histopathology and immunohistology. Blood sample was taken before surgery, and at 6 and 12 months post-surgery, to study the plasma levels of ghrelin isoforms. RESULTS: Ghrelin cells are present in all regions of the gastric mucosa, with a greater number in the body and the fundus. Difference was found in the antrum between male and female patients (p=0.018). Patients with arterial hypertension also showed a lower level of cells in antrum (p<0.05). Acylghrelin levels after surgery were significantly lower (32.83+5.6 pg/mL to 10.09+11.8 pg/mL, p<0.05). Values of desacylghrelin tended to decrease but no significant variation was observed (207.4+39.3 pg/mL to 188.84+52.3 pg/mL). CONCLUSION: Our patients show ghrelin cells in all areas of the stomach. Gender, comorbidities, and gastritis are determinant on gastric ghrelin-producing cells distribution.

Chiggers (Acariformes: Trombiculoidea) do not increase rates of infection by Batrachochytrium dendrobatidis fungus in the endemic Dwarf Mexican Treefrog Tlalocohyla smithii (Anura: Hylidae).

Amphibian populations are globally declining at an alarming rate, and infectious diseases are among the main causes of their decline. Two micro-parasites, the fungus Batrachochytrium dendrobatidis (Bd) and the virus Ranavirus (RV) have caused mass mortality of amphibians and population declines. Other, less understood epizootics are caused by macro-parasites, such as Trombiculoidea chiggers. Infection with chiggers can affect frog behavior and survival. Furthermore, synergistic effects of co-infection with both macro and micro-parasites may lead to higher morbidity. To better understand these potential synergies, we investigated the presence and co-infection by chiggers, Bd and RV in the endemic frog Tlalocohyla smithii (T. smithii). Co-infection of Bd, RV, and/or chiggers is expected in habitats that are suitable for their co-occurrence; and if infection with one parasite facilitates infection with the others. On the other hand, co-infection could decrease if these parasites were to differ in their micro-environmental requirements (i.e. niche apportionment). A total of 116 frogs of T. smithii were studied during 2014 and 2016 in three streams within the Chamela-Cuixmala Biosphere Reserve in Jalisco, Mexico. Our results show that 31% of the frogs were infected with Trombiculoidea chiggers (Hannemania sp. and Eutrombicula alfreddugesi); Hannemania prevalence increased with air temperature and decreased in sites with high canopies and with water pH values above 8.5 and below 6.7. Bd prevalence was 2.6%, RV prevalence was 0%, and none of the frogs infected with chiggers were co-infected with Bd. Together, this study suggests that chiggers do not facilitate infection with Bd, as these are apportioned in different micro-habitats. Nevertheless, the statistical power to assure this is low. We recommend further epidemiological monitoring of multiple parasites in different geographical locations in order to provide insight on the true hazards, risks and conservation options for amphibian populations.

Use of milk electrical conductivity for the differentiation of mastitis causing pathogens in Holstein cows.

Mastitis is one of the most prevalent and costly diseases in dairy cattle. Key components for adequate mastitis control are the detection of early stages of infection, as well as the selection of appropriate management interventions and therapies based on the causal pathogens associated with the infection. The objective was to characterize the pattern of electrical conductivity (EC) in milk during intramammary infection, considering specific mastitis-causing pathogen groups involvement. Cows (n = 200) identified by an in-line mastitis detection system with a positive deviation ≥15% in the manufacturer's proprietary algorithm for EC (high electrical conductivity (HEC)) were considered cases and enrolled in the study at the subsequent milking. One control (CON) cow, within normal ranges for EC, was matched to each case. A composite milk sample was collected aseptically from each cow for bacteriological culture. Milk yield (MY) and EC were recorded for each milking during ±7 days relative to enrollment. Milk cultures were categorized into gram positive (GP), gram negative (GN), other (OTH) and no growth (NOG). Data were submitted for repeated-measures analysis with EC as the dependent variable and EC status at day -1, bacteriological culture category, parity number, stage of lactation and days relative to sampling as main independent variables. Average (± standard error (SE)) EC was greater in HEC than in CON cows (12.5 ± 0.5 v. 10.8 ± 0.5 mS/cm) on the day of identification (day -1). Milk yield on day -1 was greater in CON than in HEC (37.6 ± 5.1 v. 33.5 ± 5.2 kg). For practical management purposes, average EC on day -1 was similar for the different bacteriological culture categories: 11.4 ± 0.6, 11.7 ± 0.5, 12.3 ± 0.8 and 11.7 ± 0.5 mS/cm in GN, GP, OTH and NOG, respectively. Parity number was only associated with day -1 EC in HEC group, with the greatest EC values in parity 3 (12.3 ± 0.3 mS/cm), followed by parity 2 (11.9 ± 0.2 mS/cm), parity >3 (11.6 ± 0.5 mS/cm) and primiparous cows (11.2 ± 0.2 mS/cm). An effect on EC for the interaction of day relative to identification by pathogen gram category was observed. The same interaction effect was observed on daily MY. Overall, the level of variation for MY and EC between- and within-cows was substantial, and as indicated by the model diagnostic procedures, the magnitude of the variance in the cows in the CON group resulted in deviations from normality in the residuals. We concluded that characteristic temporal patterns in EC and MY in particular pathogen groups may provide indications for differentiation of groups of mastitis-causing pathogens. Further research to build detection models including EC, MY and cow-level factors is required for accurate differentiation.

Effect of interacting conditions of water activity, temperature and incubation time on Fusarium thapsinum and Fusarium andiyazi growth and toxin production on sorghum grains.

This study examined the effect of interacting conditions of water activity (aW, 0.995, 0.98 and 0.95) and temperature (15, 25 and 30 °C) on growth rate of two Fusarium thapsinum and one F. andiyazi strains isolated from sorghum in Argentina. In addition, the effect of interacting conditions (aW × temperature × incubation time (7, 14, 21 and 28 days)) on mycotoxin production (moniliformin (MON), fusaric acid (FA) and fusarin C (FUS C)) on a sorghum grain substrate was evaluated. Statistical analysis showed that aW and temperature significantly affected growth of both species, mainly the aW. Incubation time significantly influenced mycotoxin production by both species as well, mostly for FA. Maximum growth rates of the F. thapsinum strains were obtained at the highest aW (0.995) and 25 °C and growth rate decreased as aW and temperature were reduced. The same growth profile was observed for F. andiyazi RCFA09 (maximum growth rates at 0.995-25 °C). Mycotoxin production by both species was detected at the highest aW levels whereas at 0.95 aW only low amounts of MON were produced by F. thapsinum. Maximum MON and FUS C production by both F. thapsinum strains was observed at 0.995 aW and 25-30 °C after 28 days of incubation. Also, F. thapsinum strains showed maximum FA production at the highest aW and temperature but after 14 days; after this incubation time toxin levels significantly decreased. The responses to aW and temperature of F. andiyazi were similar to that of F. thapsinum strains in relation to FA and FUS C production. Maximum levels of FA were detected at the highest aW after 14 days of incubation at 25-30 °C. Fusarin C was produced at all assayed temperatures but maximum levels were detected at 30 °C and 0.995 aW after 28 days of incubation. Two-dimensional profiles on the interactions of aW by temperature were developed from these data to identify conditions that indicate a significant risk from MON, FA and FUS C accumulation on sorghum grains. The results of this study suggest that sorghum grains could be colonized by these species and toxin production can occur, especially during development stages under field conditions at high water activity of grains or during grain storage if the drying process is slow or deficient. To our knowledge, this study described for the first time FUS C production by F. thapsinum and F. andiyazi under interacting conditions of aW, temperature and incubation time on sorghum grains.

Dual-task effects on postural sway during sit-to-stand movement in children with Down syndrome.

BACKGROUND: Cognitive and postural tasks require common cognitive mechanisms, resulting in conflicts when both tasks are simultaneously performed. The presence of neuromotor dysfunctions, such as Down syndrome, may impair coordination processes required to perform dual-tasks. The objective of this study was to investigate the dual-task effects on postural sway during sit-to-stand movements in typical children and children with Down syndrome in a cross-sectional study. METHODS: Twenty six typical children (10.2 ± 2.4 years) and 21 with Down syndrome (10.3 ± 2.3 years) performed sit-to-stand in the following conditions: (1) simple task; (2) dual-task bimanual activity (DT-Bim): sit-to-stand while carrying a tray using both hands; (3) dual-task unimanual dominant activity (DT-Uni-Dom): sit-to-stand while holding a plastic cup simulating water using the dominant hand; (4) dual-task unimanual non-dominant activity (DT-Uni-Nondom): sit-to-stand movement while holding a plastic cup simulating water. For data analysis, sit-to-stand was divided into three phases: preparation (phase 1), rising (phase 2), and stabilisation (phase 3). The following variables were calculated for each phase: anterior-posterior and medial-lateral amplitude of centre-of-pressure displacement, anterior-posterior and medial-lateral velocity of centre-of-pressure sway and area of centre-of-pressure sway. RESULTS: Children with Down syndrome showed greater sway than typical children in all sit-to-stand phases. Typical children showed greater anterior-posterior amplitude in phase 2 of sit-to-stand during DT-Uni Nondom compared with DT-Uni Dom. Children with Down syndrome during simple task condition showed greater and faster values sway in phases 2 and 3 of sit-to-stand movement than in DT-Bim activity, DT-Uni Dom activity and DT-Uni Nondom activity. During the condition of DT-Bim activity, these children showed lower anterior-posterior velocity of sway in phase 2 than during DT-Uni Dom activity. CONCLUSIONS: Children with Down syndrome showed greater postural sway during sit-to-stand than typical children. The addition of a concurrent motor task to sit-to-stand impacted postural sway in different intensities and in different ways across groups. Dual-tasks increased body sway in typical children in the DT-Uni Nondom condition compared with dominant one. In children with Down syndrome, dual-tasks decreased body sway, apparently resulting in a postural strategy of stiffness.

An imbalance in the T-helper phenotypes displayed by senescent CD4+CD28null T cells is associated with erosive arthritis (rhupus syndrome) in systemic lupus erythematosus.

OBJECTIVE: The objective was to assess the proportion of Th1, Th2 and Th17 phenotypes in senescent CD4+CD28null cells from patients with systemic lupus erythematosus (SLE) and its association with the pattern of joint involvement. METHODS: This cross-sectional study was performed in SLE patients with erosive arthritis (rhupus) or nondeforming, nonerosive arthritis. Total CD4+CD28null cells as well as the proportion of these cells expressing T-bet, GATA3 or RORγt were analyzed by color-flow cytometry. Serum osteopontin levels were measured by ELISA. RESULTS: Eighteen SLE patients (nine with rhupus and nine with nonerosive arthritis) were studied. The percentage of CD4+CD28null/CD4+ cells (17.7%, 10.3-25.0% versus 9.4%, 8.1-22.4%; P = 0.386) as well as the osteopontin levels (5800, 5,134-5995 pg/ml versus 5578, 5171-5717 pg/ml; P > 0.05) were similar in both groups. A higher percentage of CD4+CD28nullT-bet+ cells (42.8%, 33.5-53.4% versus 30.0%, 23.3-34.2%) but a lower percentage of CD4+CD28nullGATA3+ cells (3.1%, 1.7-5.6% versus 6.2%, 2.6-18.4%) was observed in patients with rhupus than in their counterparts ( P = 0.016). The frequency of CD4+CD28nullRORγt+ cells was similar between groups. CONCLUSIONS: In patients with rhupus, senescent CD4+CD28null cells are preferentially polarized to a Th1 phenotype, whereas this is partial towards Th2 in lupus patients with a nonerosive arthritis pattern.

Beneficial changes on plasma apolipoproteins A and B, high density lipoproteins and oxidized low density lipoproteins in obese women after bariatric surgery: comparison between gastric bypass and sleeve gastrectomy.

BACKGROUND: The beneficial effects in lipid profiles after obesity surgery might be associated with the decrease in cardiovascular risk. However, direct comparison between different surgical techniques has not been extensively performed. METHODS: In the present study we compare 20 obese women submitted to laparoscopic Roux en Y gastric bypass (RYGB) with 20 women submitted to sleeve gastrectomy (SG). Twenty control women matched for age and baseline cardiovascular risk were also included. Both patients and controls were followed up for 1 year after surgery or conventional treatment with diet and exercise, respectively. Lipid profiles were measured at baseline, 6 and 12 months later. Carotid intima-media thickness was measured by ultrasonography at baseline and at the end of the study. RESULTS: Women submitted to bariatric surgery showed a decrease in total cholesterol, triglycerides, oxidized-LDL and ApoB, and an increase in HDL and ApoA concentrations that occurred regardless of the surgical procedure. LDL concentrations, however, decreased only after RYGB whereas Lp(a) showed no changes. We did not observe any correlation between the changes in serum lipid concentrations and those in carotid intima-media thickness. CONCLUSIONS: Sleeve gastrectomy and gastric bypass induce a similar beneficial effect on serum lipids in women with high cardiovascular risk 1 year after surgery.

Elongated odontoid process in late Holocene skeletal remains from B6 archaeological site, Mendoza, Argentina.

The odontoid process of the axis can be affected by congenital or acquired pathologies. While abnormalities such as os odontoideum, agenesis, and fractures are reported in archaeological remains, the abnormality of an elongated length of the odontoid process has not been described in the paleopathological literature. The aim of this paper is to evaluate two individuals with elongated odontoid processes from a skeletal assemblage from the B6 archaeological site (Mendoza, Argentina), and to discuss the possible etiologies of the condition, with particular attention given to the relation to trauma and Crowned Dens Syndrome (CDS), a condition characterized by the ossification of ligaments of the odontoid process of the second cervical vertebra.

Obstáculos y retos para el desarrollo de sistemas de información en el sector salud / Obstacles and challenges for the development of information systems in the health sector

Objetivo. El propósito de los Sistemas de Información en de la Salud (SIS) es mejorar la salud de los individuos y las poblaciones mediante la aplicación apropiada del conocimiento generado por la organización de la información en dichos sistemas. Materiales y métodos. Se realizó una revisión sistemática de literatura a través de las experiencias y lineamientos en el desarrollo y la implementación de un SIS. Resultados. El análisis de los requisitos es el punto de partida para el desarrollo o la adquisición de cualquier producto de software. El SIS debe contemplar la inclusión de los datos necesarios para la investigación y permitir su organización dependiendo del tipo de investigación que se quiera realizar; debe simplificar y acelerar el acceso a la información crítica al mismo tiempo que controla el acceso a los datos; debe facilitar el tratamiento estadístico de grandes cantidades de datos; y, finalmente, debe facilitar el intercambio de datos entre diversos sistemas. Conclusiones. El conjunto de los obstáculos y retos para el desarrollo de los SIS enumerados en este artículo confirma la gran complejidad que presenta este tipo de sistemas de información, para ello se requiere de una planeación madura y detallada.

Objective. The purpose of Information Systems in Health (SIS) is to improve the health of individuals and populations through the appropriate application of knowledge generated by the organization of information in such systems. Materials and methods. A literature review was conducted through the experiences and results obtained in the development and implementation of an SIS. Results. The analysis of the requirements is the starting point for the development or acquisition of any software product. The SIS must consider the inclusion of the necessary data for the investigation and allow for its organization depending on the type of inquiry that will be carried out. It must simplify and accelerate access to critical information while controlling access to data, facilitate the statistical processing of large amounts of data, and finally facilitate the exchange of data between different systems. Conclusions. The set of obstacles and challenges for the development of the SIS listed in this article confirms the high complexity of this type of information systems for which mature and detailed planning is needed.

Hepatitis E virus infection of slaughtered healthy pigs in Brazil.

Hepatitis E virus (HEV) is an emerging pathogen that can be transmitted through contaminated raw or undercooked meat derived from domestic pigs. HEV infections have been documented among pig herds, pig products and environmental samples raising concern about the spread of the virus. HEV genotypes 3 and 4 are considered zoonotic and have been linked to human cases. HEV was detected in 51 of 335 bile samples (15.2%) from healthy pigs in Minas Gerais, Brazil. Phylogenetic analysis of partial sequences from ORF1 and ORF2 regions yielded discordant results, assigning isolates to subtypes 3c and 3i, respectively, suggesting intragenotypic HEV recombination.