Clinical features and prognosis of malignant small bowel tumors: Experience from a university hospital in Chile.

BACKGROUND: Small bowel tumors (SBT) are infrequent and represent a small proportion of digestive neoplasms. There is scarce information about SBT in Latin America. AIM: To describe the epidemiology, clinical characteristics, diagnostic methods, and survival of malignant SBTs. METHODS: Retrospective observational study of adult patients with histopathological diagnosis of SBT between 2007 and 2021 in a university hospital in Chile. RESULTS: A total of 104 patients [51.9% men; mean age 57 years] with SBT. Histological type: neuroendocrine tumor (NET) (43.7%, n=38), gastrointestinal stromal tumors (GIST) (21.8%, n=19), lymphoma (17.2%, n=15) and adenocarcinoma (AC) (11.5%, n=10). GIST was more frequent in duodenum (50%; n=12) and NET in the ileum (65.8%; n=25). Metastasis was observed in 17 cases, most commonly from colon and melanoma. Nausea and vomiting were significantly more often observed in AC (p=0.035), as well as gastrointestinal bleeding in GIST (p=0.007). The most common diagnostic tools were CT and CT enteroclysis with an elevated diagnostic yield (86% and 94% respectively). The 5-year survival of GIST, NET, lymphoma and AC were 94.7% (95%CI: 68.1-99.2), 82.2% (95%CI: 57.6-93.3), 40.0% (95%CI: 16.5-82.8) and 25.9% (95%CI: 4.5-55.7%), respectively. NET (HR 6.1; 95%CI: 2.1-17.2) and GIST (HR 24.4; 95%CI: 3.0-19.8) were independently associated with higher survival compared to AC, adjusted for age and sex. CONCLUSIONS: Malignant SBT are rare conditions and NETs are the most common histological subtype. Clinical presentation at diagnosis, location or complications may suggest a more probable diagnosis. GIST and NET are associated with better survival compared to other malignant subtypes.

[Reduction in Helicobacter pylori infection among patients referred for upper gastrointestinal endoscopy in Santiago, Chile, between 2010-2020]. / Reducción de la infección por Helicobacter pylori en pacientes derivados a endoscopia digestiva alta en Santiago de Chile entre 2010-2020.

Latin America presents a high prevalence of Helicobacter pylori(Hp) infection. Between1996-2003, the prevalence in Santiago, Chile, was 70%; recent studies indicate a decreasein this infection. Updating the frequency of Hp is crucial due to its associated health impact. OBJECTIVE: Our objective was to describe the trend in Hp infection in patients undergoingambulatory esophagogastroduodenoscopy (EGD) in a Chilean population. MATERIALS AND METHODS: A retrospective observational study was conducted on patients over 18 years old who attended a first EGD with a rapid urease test between 2010-2020. Time trendswere described through time series analysis. A Poisson model was constructed to estimatethe risk of infection, adjusted for age and gender. RESULTS: 11,355 patients were included[66.9% females; mean age 52 years; Hp 41.6%]. Male gender presented a higher frequencyof Hp infection [RR 1.13; (95% CI: 1.08-1.18)].Hp frequency infection decreased significantlyfrom 45.1% in 2010 to 29% in 2020, with a 36% lower probability of Hp infection in 2020 compared to 2010 [RR 0.64;(95% CI: 0.55-0.74)]. A progressive decline in Hp infectiontrend was projected, reaching values close to 25% by year 2025. CONCLUSION: A significantreduction in Hpinfection was observed between 2010-2020. This decrease could be explained by the implementation of public health policies in the last decade associated with socio-sanitary changes.

Implementation of the updated Sydney system biopsy protocol improves the diagnostic yield of gastric preneoplastic conditions: Results from a real-world study.

BACKGROUND: The updated Sydney system biopsy protocol (USSBP) standardizes the sampling of gastric biopsies for the detection of preneoplastic conditions (e.g., gastric intestinal metaplasia [GIM]), but the real-world diagnostic yield is not well-described. AIM: To determine whether regular application of USSBP is associated with higher detection of chronic atrophic gastritis (CAG), GIM and autoimmune gastritis (AIG). METHODS: We performed a real-world retrospective study at an academic urban tertiary hospital in Chile. We manually reviewed medical records from consecutive patients undergoing esophagogastroduodenoscopy (EGD) from January to December 2017. Seven endoscopists who performed EGDs were categorized into two groups (USSBP 'regular' and USSBP 'infrequent') based on USSBP adherence, using minimum 20% adherence as the prespecified threshold. Multivariable logistic regression models were used to estimate the odds ratios (aOR) and 95% confidence intervals (CI) for the association between endoscopist groups and the likelihood of diagnosing CAG, GIM or AIG. RESULTS: 1206 patients were included in the study (mean age: 58.5; 65.3% female). The USSBP regular group demonstrated a higher likelihood of detecting CAG (20% vs. 5.3%; aOR 4.03, 95%CI: 2.69-6.03), GIM (12.2% vs. 3.4%; aOR 3.91, 95%CI: 2.39-6.42) and AIG (2.9% vs. 0.8%; aOR 6.52, 95%CI: 1.87-22.74) compared to infrequent group. Detection of advanced-stage CAG (Operative Link for Gastritis Assessment stage III/IV) was significantly higher in the USSBP regular vs. infrequent group (aOR 5.84, 95%CI: 2.23-15.31). CONCLUSIONS: Routine adherence to USSBP increases the detection rates of preneoplastic conditions, including CAG, GIM and AIG. Standardized implementation of USSBP should be considered in high gastric cancer risk populations.

On the role of continuous symmetries in the solution of the three-dimensional Euler fluid equations and related models.

We review and apply the continuous symmetry approach to find the solution of the three-dimensional Euler fluid equations in several instances of interest, via the construction of constants of motion and infinitesimal symmetries, without recourse to Noether's theorem. We show that the vorticity field is a symmetry of the flow, so if the flow admits another symmetry then a Lie algebra of new symmetries can be constructed. For steady Euler flows this leads directly to the distinction of (non-)Beltrami flows: an example is given where the topology of the spatial manifold determines whether extra symmetries can be constructed. Next, we study the stagnation-point-type exact solution of the three-dimensional Euler fluid equations introduced by Gibbon et al. (Gibbon et al. 1999 Physica D 132, 497-510. (doi:10.1016/S0167-2789(99)00067-6)) along with a one-parameter generalization of it introduced by Mulungye et al. (Mulungye et al. 2015 J. Fluid Mech. 771, 468-502. (doi:10.1017/jfm.2015.194)). Applying the symmetry approach to these models allows for the explicit integration of the fields along pathlines, revealing a fine structure of blowup for the vorticity, its stretching rate and the back-to-labels map, depending on the value of the free parameter and on the initial conditions. Finally, we produce explicit blowup exponents and prefactors for a generic type of initial conditions. This article is part of the theme issue 'Mathematical problems in physical fluid dynamics (part 2)'.

Image Encryption Using Elliptic Curves and Rossby/Drift Wave Triads.

We propose an image encryption scheme based on quasi-resonant Rossby/drift wave triads (related to elliptic surfaces) and Mordell elliptic curves (MECs). By defining a total order on quasi-resonant triads, at a first stage we construct quasi-resonant triads using auxiliary parameters of elliptic surfaces in order to generate pseudo-random numbers. At a second stage, we employ an MEC to construct a dynamic substitution box (S-box) for the plain image. The generated pseudo-random numbers and S-box are used to provide diffusion and confusion, respectively, in the tested image. We test the proposed scheme against well-known attacks by encrypting all gray images taken from the USC-SIPI image database. Our experimental results indicate the high security of the newly developed scheme. Finally, via extensive comparisons we show that the new scheme outperforms other popular schemes.

Phase and precession evolution in the Burgers equation.

We present a phenomenological study of the phase dynamics of the one-dimensional stochastically forced Burgers equation, and of the same equation under a Fourier mode reduction on a fractal set. We study the connection between coherent structures in real space and the evolution of triads in Fourier space. Concerning the one-dimensional case, we find that triad phases show alignments and synchronisations that favour energy fluxes towards small scales --a direct cascade. In addition, strongly dissipative real-space structures are associated with entangled correlations amongst the phase precession frequencies and the amplitude evolution of Fourier triads. As a result, triad precession frequencies show a non-Gaussian distribution with multiple peaks and fat tails, and there is a significant correlation between triad precession frequencies and amplitude growth. Links with dynamical systems approach are briefly discussed, such as the role of unstable critical points in state space. On the other hand, by reducing the fractal dimension D of the underlying Fourier set, we observe: i) a tendency toward a more Gaussian statistics, ii) a loss of alignment of triad phases leading to a depletion of the energy flux, and iii) the simultaneous reduction of the correlation between the growth of Fourier mode amplitudes and the precession frequencies of triad phases.

Robust energy transfer mechanism via precession resonance in nonlinear turbulent wave systems.

A robust energy transfer mechanism is found in nonlinear wave systems, which favors transfers toward modes interacting via triads with nonzero frequency mismatch, applicable in meteorology, nonlinear optics and plasma wave turbulence. We emphasize the concepts of truly dynamical degrees of freedom and triad precession. Transfer efficiency is maximal when the triads' precession frequencies resonate with the system's nonlinear frequencies, leading to a collective state of synchronized triads with strong turbulent cascades at intermediate nonlinearity. Numerical simulations confirm analytical predictions.

Alignments of triad phases in extreme one-dimensional Burgers flows.

We analyze the fine structure of nonlinear modal interactions in inviscid and viscous Burgers flows in 1D, which serve as toy models for the Euler and Navier-Stokes dynamics. This analysis is focused on preferential alignments characterizing the phases of Fourier modes participating in triadic interactions, which are key to determining the nature of energy fluxes between different scales. We develop diagnostic tools designed to probe the level of coherence among triadic interactions and apply them to Burgers flows corresponding to different initial conditions, including unimodal, extreme (in the sense of maximizing the growth of enstrophy in finite time), and generic. We find that in all cases triads involving energy-containing Fourier modes align their phases so as to maximize the energy flux toward small scales, and most of this flux is realized by only a handful of triads revealing a universal statistical distribution. We then identify individual triads making the largest contributions to the flux at different wave numbers and show that they represent a mixture of local and nonlocal interactions, with the latter becoming dominant at later times. These results point to the possibility of constructing a strongly reduced modal representation of Burgers flows that would require a much smaller number of degrees of freedom. Another interesting observation is that removing the spatial coherence from the extreme initial data (by randomizing the phases while retaining the magnitudes of the Fourier coefficients) does not profoundly change the nature of triadic interactions and synchronization as well as the resulting fluxes in these flows.

Understanding surgical smoke in laparoscopy through Lagrangian Coherent Structures.

In laparoscopic surgery, one of the main byproducts is the gaseous particles, called surgical smoke, which is found hazardous for both the patient and the operating room staff due to their chemical composition, and this implies a need for its effective elimination. The dynamics of surgical smoke are monitored by the underlying flow inside the abdomen and the hidden Lagrangian Coherent Structures (LCSs) present therein. In this article, for an insufflated abdomen domain, we analyse the velocity field, obtained from a computational fluid dynamics model, first, by calculating the flow rates for the outlets and then by identifying the patterns which are responsible for the transportation, mixing and accumulation of the material particles in the flow. From the finite time Lyapunov exponent (FTLE) field calculated for different cross-sections of the domain, we show that these material curves are dependent on the angle, positions and number of the outlets, and the inlet. The ridges of the backward FTLE field reveal the regions of vortex formation, and the maximum accumulation, details which can inform the effective placement of the instruments for efficient removal of the surgical smoke.

Structure-function assessment of 3D-printed porous scaffolds by a low-cost/open source fused filament fabrication printer.

Additive manufacturing encompasses a plethora of techniques to manufacture structures from a computational model. Among them, fused filament fabrication (FFF) relies on heating thermoplastics to their fusion point and extruding the material through a nozzle in a controlled pattern. FFF is a suitable technique for tissue engineering, given that allows the fabrication of 3D-scaffolds, which are utilized for tissue regeneration purposes. The objective of this study is to assess a low-cost/open-source 3D printer (In-House), by manufacturing both solid and porous samples with relevant microarchitecture in the physiological range (100-500 µm pore size), using an equivalent commercial counterpart for comparison. For this, compressive tests in solid and porous scaffolds manufactured in both printers were performed, comparing the results with finite element analysis (FEA) models. Additionally, a microarchitectural analysis was done in samples from both printers, comparing the measurements of both pore size and porosity to their corresponding computer-aided design (CAD) models. Moreover, a preliminary biological assessment was performed using scaffolds from our In-House printer, measuring cell adhesion efficiency. Finally, Fourier transform infrared spectroscopy - attenuated total reflectance (FTIR-ATR) was performed to evaluate chemical changes in the material (polylactic acid) after fabrication in each printer. The results show that the In-House printer achieved generally better mechanical behavior and resolution capacity than its commercial counterpart, by comparing with their FEA and CAD models, respectively. Moreover, a preliminary biological assessment indicates the feasibility of the In-House printer to be used in tissue engineering applications. The results also show the influence of pore geometry on mechanical properties of 3D-scaffolds and demonstrate that properties such as the apparent elastic modulus (Eapp) can be controlled in 3D-printed scaffolds.

The efficacy of monepantel, an amino-acetonitrile derivative, against gastrointestinal nematodes of sheep in three countries of southern Latin America.

The efficacy of the novel anthelmintic, monepantel (an amino-acetonitrile derivative), was investigated in sheep naturally infected with gastrointestinal nematodes in five studies in Argentina, Brazil, and Uruguay. Monepantel, administered at 2.5 mg/kg liveweight, was highly effective (>99.7%) against Haemonchus contortus, Teladorsagia (Ostertagia) circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Cooperia curticei, Cooperia mcmasteri, Cooperia oncophora, Cooperia pectinata, Cooperia punctata, and Nematodirus spathiger, including strains resistant to the older broad-spectrum anthelmintics. Efficacy against C. mcmasteri, C. pectinata, and C. punctata is documented for the first time. The treatment with monepantel was well tolerated by the sheep.

Perceived Resources and Satisfaction With Food-Related Life Among Ecuadorian Elderly.

OBJECTIVE: To identify variables that explain satisfaction with food-related life in Ecuadorian elderly people. DESIGN: Stratified random sampling with proportional affixation within each retirement home was conducted based on the rate of rurality, gender, age, and living circumstances. SETTING: Retirement homes in Guayaquil, Ecuador. PARTICIPANTS: The sample consisted of 817 elderly people of both genders (47.5% women; mean age 73.7 years; SD 7.45 years; range 60-101 years) registered in retirement homes located in Guayaquil, Ecuador. MAIN OUTCOME MEASURES: Satisfaction With Life scale, satisfaction with food-related life (SWFL), and 22 food-related perceived resources. ANALYSIS: Generalized linear models. RESULTS: Gender, food consumption expenditure, satisfaction with economic situation, unhealthy days, family importance, food-related lifestyles, food neophobia, and the sum of 22 resources were found to be associated with SWFL. In addition, the Pearson bivariate correlation between the Satisfaction With Life scale and SWFL was .38 (P < .01). CONCLUSIONS: Perceived resources contributed to SWFL and the greatest satisfaction with life was observed among older adults who were more satisfied with their food.

Analysis of the characteristics and components for the frailty syndrome in older adults from central Chile. The PIEI-ES study.

OBJECTIVE: To determine the prevalence and to characterize frailty in elderly subjects in four urban provincial capitals and two rural communes from Maule Region in Chile. DESIGN: Cross-sectional study. PARTICIPANTS: 1205 participants aged 65 and older. METHODS: The dataset was obtained from the PIEI-ES Study. Frailty syndrome was determined according to the criteria proposed by Fried. Data collection included questionnaires. RESULTS: The study sample included 1205 individuals, of which 68% were females. Mean age was 73 years. The overall prevalence of frailty was 24.6%. Increase prevalence of frailty was observed in people 80 years old and older, both in women and men. Using adjusted logistic regression, advanced frailty state was more likely to occur in subjects with cognitive impairment. CONCLUSION: This study provides evidence that frailty may be related with cognitive functioning, educational level and nutritional status in older adults.

Reducción de la infección por Helicobacter pylori en pacientes derivados a endoscopia digestiva alta en Santiago de Chile entre 2010-2020 / Reduction in Helicobacter pylori infection among patients referred for upper gastrointestinal endoscopy in Santiago, Chile, between 2010-2020

RESUMEN Latinoamérica presenta una alta prevalencia de infección por Helicobacter pylori (Hp). Entre 1996-2003 la prevalencia en Santiago de Chile fue del 70%; estudios recientes presentan una disminución en esta infección. Actualizar la frecuencia de Hp es fundamental debido a su impacto en la salud asociado. Objetivo: Nuestro objetivo fue describir la tendencia de la infección por Hp en pacientes que asisten a endoscopía digestiva alta (EDA) ambulatoria en una población chilena. Materiales y métodos: Se realizó un estudio observacional retrospectivo de pacientes mayores de 18 años que asistieron a una primera EDA con test rápido de ureasa entre 2010-2020. La tendencia en el tiempo fue descrita mediante análisis de series de tiempo. Se construyó un modelo Poisson para estimar el riesgo de infección, ajustado por edad y sexo. Resultados: Se incluyeron 11 355 pacientes [66,9% mujeres; edad media 52 años; Hp 41,6%]. El sexo masculino presentó una mayor frecuencia de infección por Hp [RR 1,13; (IC95%:1,08-1,18)]. La frecuencia de Hp disminuyó significativamente desde 45,1% en 2010 hasta 29% en 2020, con 36% menor probabilidad de presentar infección por Hp en 2020 con respecto al 2010 [RR 0,64; (IC95%:0,55-0,74)]. Se proyectó un descenso progresivo en la tendencia de infección por Hp hasta valores cercanos al 25% para el año 2025. Conclusión: Se observó una reducción significativa en la infección por Hp entre los años 2010-2020. Esta disminución pudiese ser explicada mediante la incorporación de políticas públicas de salud en la última década asociadas a cambios sociosanitarios.

ABSTRACT Latin America presents a high prevalence of Helicobacter pylori (Hp) infection. Between 1996-2003, the prevalence in Santiago, Chile, was 70%; recent studies indicate a decrease in this infection. Updating the frequency of Hp is crucial due to its associated health impact. Objective: Our objective was to describe the trend in Hp infection in patients undergoing ambulatory esophagogastroduodenoscopy (EGD) in a Chilean population. Materials and methods: A retrospective observational study was conducted on patients over 18 years old who attended a first EGD with a rapid urease test between 2010-2020. Time trends were described through time series analysis. A Poisson model was constructed to estimate the risk of infection, adjusted for age and gender. Results: 11,355 patients were included [66.9% females; mean age 52 years; Hp 41.6%]. Male gender presented a higher frequency of Hp infection [RR 1.13; (95% CI: 1.08-1.18)]. Hp frequency infection decreased significantly from 45.1% in 2010 to 29% in 2020, with a 36% lower probability of Hp infection in 2020 compared to 2010 [RR 0.64; (95% CI: 0.55-0.74)]. A progressive decline in Hp infection trend was projected, reaching values close to 25% by year 2025. Conclusion: A significant reduction in Hp infection was observed between 2010-2020. This decrease could be explained by the implementation of public health policies in the last decade associated with socio-sanitary changes.

First Wave of the 2016-17 Cholera Outbreak in Hodeidah City, Yemen - ACF Experience and Lessons Learned.

INTRODUCTION: Although cases were reported only in 2010 and 2011, cholera is probably endemic in Yemen. In the context of a civil war, a cholera outbreak was declared in different parts of the country October 6th, 2016. This paper describes the ACF outbreak response in Hodeidah city from October 28th, 2016 to February 28th, 2017 in order to add knowledge to this large outbreak. METHODS: The ACF outbreak response in Hodeidah city included a case management component and prevention measures in the community. In partnership with the Ministry of Public Health and Population of Yemen (MoPHP), the case management component included a Cholera Treatment Center (CTC) implemented in the Al Thoraw hospital, 11 Oral Rehydration Therapy Corners (ORTCs) and an active case finding system. In partnership with other stakeholders, prevention measures in the community, including access to safe water and hygiene promotion, were implemented in the most affected communities of the city. RESULTS: From October 28th, 2016 until February 28th, 2017, ACF provided care to 8,270 Acute Watery Diarrhea (AWD) cases, of which 5,210 (63%) were suspected cholera cases, in the CTC and the 11 ORTCs implemented in Hodeidah city. The attack rate was higher among people living in Al Hali district, with a peak in November 2016. At the CTC, 8% of children under 5 years-old also presented with Severe Acute Malnutrition (SAM). The Case-Fatality Rate (CFR) was low (0.07%) but 15% of admitted cases defaulted for cultural and security reasons. Environmental management lacked the information to appropriately target affected areas. Financial resources did not allow complete coverage of the city. CONCLUSION: Response to the first wave of a large cholera outbreak in Hodeidah city was successful in maintaining a CFR <1% in the CTC. However, considering the actual context of Yemen and its water infrastructure, much more efforts are needed to control the current outbreak resurgence.

Derivation of the Biot-Savart equation from the nonlinear Schrödinger equation.

We present a systematic derivation of the Biot-Savart equation from the nonlinear Schrödinger equation, in the limit when the curvature radius of vortex lines and the intervortex distance are much greater than the vortex healing length, or core radius. We derive the Biot-Savart equations in Hamiltonian form with Hamiltonian expressed in terms of vortex lines,H=κ(2)/8π∫(|s-s'|>ξ(*))(ds·ds')/|s-s'|,with cutoff length ξ(*)≈0.3416293/√(ρ(0)), where ρ(0) is the background condensate density far from the vortex lines and κ is the quantum of circulation.

Interplay between the Beale-Kato-Majda theorem and the analyticity-strip method to investigate numerically the incompressible Euler singularity problem.

Numerical simulations of the incompressible Euler equations are performed using the Taylor-Green vortex initial conditions and resolutions up to 4096^{3}. The results are analyzed in terms of the classical analyticity-strip method and Beale, Kato, and Majda (BKM) theorem. A well-resolved acceleration of the time decay of the width of the analyticity strip δ(t) is observed at the highest resolution for 3.7

Nitrogen and potassium variation on contaminant removal for a vertical subsurface flow lab scale constructed wetland.

Lab scale constructed wetlands were used to evaluate organic load removal efficiency. Bioreactors were fed with synthetic wastewater (SW) with varying concentrations of nitrogen and potassium. Reactors were planted with species Phragmites australis. Fed theoretic COD was adjusted to 240.0mg-O(2)L(-1), nitrogen levels were 10 and 40 mg-NL(-1) (ammonium sulfate), potassium levels were 5 and 31 mg-KL(-1) (potassium monobasic phosphate). The higher biomass yield, for 0.5 and 0.775 N:K ratios, was related with higher organic load removal. The ratio N:K showed significant differences for organic load abatement, when 1:0.5 and 1:0.775 N:K ratios were applied, 96.8% efficiency was obtained, whereas N:K ratio of 1:0.125 had efficiency of 92.1% and N:K ratio of 1:3.1 showed an efficiency of 90.5%. For planted bioreactor E(H) decreased in 162.7 mV from sample port to 5 cm down to 35 cm depth, while for the bioreactor without plant showed an E(H) decrement of only 17.7 mV.

Apoptosis is directly related to intracellular amyloid accumulation in a cell line derived from the cerebral cortex of a trisomy 16 mouse, an animal model of Down syndrome.

Human Down syndrome (DS) represents the most frequent cause of mental retardation associated to a genetic condition. DS also exhibits a characteristic early onset of neuropathology indistinguishable from that observed in Alzheimer's disease (AD), namely the deposition of the beta-amyloid peptide. Early endosomal dysfunction has been described in individuals with DS and AD, suggesting an important role of this subcellular compartment in the onset and progression of the pathology. On the other hand, cholesterol activates the amyloidogenic processing pathway for the amyloid precursor protein, and the lipoprotein receptor-related peptide interacts with the beta-amyloid peptide. In the present work, using cell lines derived from the cortex of both normal and trisomy 16 mice (Ts16), an animal model of DS, we showed that the application of exogenous beta-amyloid has cytotoxic effects, expressed in decreased viability and increased apoptosis. Supplementation of the culture media with cholesterol associated to lipoprotein increased cell viability in both cell lines, but apoptosis decreased only in the normal cell line. Further, intracellular beta-amyloid content was elevated in trisomic cells following cholesterol treatment, with higher values in the trisomic cell line. Immunocytochemical detection showed intracellular accumulation of exogenous beta-amyloid in Rab4-positive compartments, which are known to be associated to endosomal recycling. The results suggest that the intracellular beta-amyloid pool plays a central role in apoptosis-mediated cell death in the trisomic condition.