Bonding Performance of Glass Fiber-Reinforced Polymer Bars under the Influence of Deformation Characteristics.

Glass fiber-reinforced polymer (GFRP) of high performance, as a relatively ideal partial or complete substitute for steel, could increase the possibility of adapting structures to changes in harsh weather environments. While GFRP is combined with concrete in the form of bars, the mechanical characteristics of GFRP cause the bonding behavior to differ significantly from that of steel-reinforced members. In this paper, a central pull-out test was applied, according to ACI440.3R-04, to analyze the influence of the deformation characteristics of GFRP bars on bonding failure. The bond-slip curves of the GFRP bars with different deformation coefficients exhibited distinct four-stage processes. Increasing the deformation coefficient of the GFRP bars is able to significantly improve the bond strength between the GFRP bars and the concrete. However, while both the deformation coefficient and concrete strength of the GFRP bars were increased, the bond failure mode of the composite member was more likely to be changed from ductile to brittle. The results show members with larger deformation coefficients and moderate concrete grades, which generally have excellent mechanical and engineering properties. By comparing with the existing bond and slip constitutive models, it was found that the proposed curve prediction model was able to well match the engineering performance of GFRP bars with different deformation coefficients. Meanwhile, due to its high practicality, a four-fold model characterizing representative stress for the bond-slip behavior was recommended in order to predict the performance of the GFRP bars.

Application of the Small Punch Creep-Recovery Test (SPCRT) for the Estimation of Large-Amplitude Viscoelastic Properties of Polymers.

The Small Punch Creep-Recovery Test (SPCRT) is a novel miniature test used to estimate the viscoelastic properties of polymers and biomaterials. The current investigation related to the SPCRT is limited to Finite Element Method (FEM) simulations and experimental tests on PVC. The aim of this investigation was focused on: (i) extending the experimental tests to other polymers with dissimilar viscoelastic properties; (ii) deepening the influence of non-linear viscoelastic properties in the estimation capabilities of the SPCRT; and (iii) developing a numerical methodology to estimate and take into account the viscoelastic recovery produced during the unloading step of compressive creep-recovery tests (CCRT) and SPCRTs. The experimental tests (CCRTs and SPCRTs) were done on polyethylene PE 500, polyoxymethylene POM C, nylon PA 6, and polytetrafluoroethylene (PTFE), with a range of creep loads, in the case of CCRTs, in the whole elastic regime and the surroundings of the yield strength of each material. The experimental results confirmed that the SPCRT was an accurate and reliable testing method for linear viscoelastic polymers. For a non-linear viscoelastic behavior, SPCRT estimated the viscoelastic properties obtained from CCRTs for creep loads near the yield strength of the polymer, which corresponded with large-amplitude viscoelastic properties in dynamic creep testing. In order to consider the viscoelastic recovery generated in the unloading step of CCRTs and SPCRTs, a Maxwell-Wiechert model with two branches was used, simulating the different steps of the experimental tests, and solving numerically the differential equation of the Maxwell-Wiechert model with the Runge-Kutta-Fehlberg (RKF) numerical method. The coefficients of the elements of the Maxwell-Wiechert model were estimated approaching the straining curve of the recovery step of the simulation with the same curve registered on each experimental test. Experimental CCRTs with different unloading times demonstrated that the use of this procedure derived in no influence of the unloading step time in the viscoelastic properties estimation.

Recombinant human chorionic gonadotropin induces signaling pathways towards cancer prevention in the breast of BRCA1/2 mutation carriers.

BACKGROUND: Strategies for breast cancer prevention in women with germline BRCA1/2 mutations are limited. We previously showed that recombinant human chorionic gonadotropin (r-hCG) induces mammary gland differentiation and inhibits mammary tumorigenesis in rats. The present study investigated hCG-induced signaling pathways in the breast of young nulliparous women carrying germline BRCA1/2 mutations. METHODS: We performed RNA-sequencing on breast tissues from 25 BRCA1/2 mutation carriers who received r-hCG treatment for 3 months in a phase II clinical trial, we analyzed the biological processes, reactome pathways, canonical pathways, and upstream regulators associated with genes differentially expressed after r-hCG treatment, and validated genes of interest. RESULTS: We observed that r-hCG induces remarkable transcriptomic changes in the breast of BRCA1/2 carriers, especially in genes related to cell development, cell differentiation, cell cycle, apoptosis, DNA repair, chromatin remodeling, and G protein-coupled receptor signaling. We revealed that r-hCG inhibits Wnt/ß-catenin signaling, MYC, HMGA1 , and HOTAIR , whereas activates TGFB/TGFBR-SMAD2/3/4, BRCA1, TP53, and upregulates BRCA1 protein. CONCLUSION: Our data suggest that the use of r-hCG at young age may reduce the risk of breast cancer in BRCA1/2 carriers by inhibiting pathways associated with stem/progenitor cell maintenance and neoplastic transformation, whereas activating genes crucial for breast epithelial differentiation and lineage commitment, and DNA repair.

A multiparametric advection-diffusion reduced-order model for molecular transport in scaffolds for osteoinduction.

Scaffolds are microporous biocompatible structures that serve as material support for cells to proliferate, differentiate and form functional tissue. In particular, in the field of bone regeneration, insertion of scaffolds in a proper physiological environment is known to favour bone formation by releasing calcium ions, among others, triggering differentiation of mesenchymal cells into osteoblasts. Computational simulation of molecular distributions through scaffolds is a potential tool to study the scaffolds' performance or optimal designs, to analyse their impact on cell differentiation, and also to move towards reduction in animal experimentation. Unfortunately, the required numerical models are often highly complex and computationally too costly to develop parametric studies. In this context, we propose a computational parametric reduced-order model to obtain the distribution of calcium ions in the interstitial fluid flowing through scaffolds, depending on several physical parameters. We use the well-known Proper Orthogonal Decomposition (POD) with two different variations: local POD and POD with quadratic approximations. Computations are performed using two realistic geometries based on a foamed and a 3D-printed scaffolds. The location of regions with high concentration of calcium in the numerical simulations is in fair agreement with regions of bone formation shown in experimental observations reported in the literature. Besides, reduced-order solutions accurately approximate the reference finite element solutions, with a significant decrease in the number of degrees of freedom, thus avoiding computationally expensive simulations, especially when performing a parametric analysis. The proposed reduced-order model is a competitive tool to assist the design of scaffolds in osteoinduction research.

The role of gene to gene interaction in the breast's genomic signature of pregnancy.

Full-term pregnancy at an early age confers long-term protection against breast cancer. Published data shows a specific transcriptomic profile controlling chromatin remodeling that could play a relevant role in the pregnancy-induced protection. This process of chromatin remodeling, induced by the breast differentiation caused by the first full-term pregnancy, has mainly been measured by the expression level of genes individually considered. However, genes equally expressed during the process of chromatin remodeling may behave differently in their interaction with other genes. These changes at the gene cluster level could constitute an additional dimension of chromatin remodeling and therefore of the pregnancy-induced protection. In this research, we apply Information and Graph Theories, Differential Co-expression Network Analysis, and Multiple Regression Analysis, specially designed to examine structural and informational aspects of data sets, to analyze this question. Our findings demonstrate that, independently of the changes in the gene expression at the individual level, there are significant changes in gene-gene interactions and gene cluster behaviors. These changes indicate that the parous breast, through the process of early full-term pregnancy, generates more modules in the networks, with higher density, and a genomic structure performing additional and more complex functions than those found in the nulliparous breast.

Cold Expansion Process with Multiple Balls-Numerical Simulation and Comparison with Single Ball and Tapered Mandrels.

Cold expansion technology is an extended method used in aeronautics to increase fatigue life of holes and hence extending inspection intervals. During the cold expansion process, a mechanical mandrel is forced to pass along the hole generating compressive residual hoop stresses. The most widely accepted geometry for this mandrel is the tapered one and simpler options like balls have generally been rejected based on the non-conforming residual hoop stresses derived from their use. In this investigation a novelty process using multiple balls with incremental interference, instead of a single one, was simulated. Experimental tests were performed to validate the finite element method (FEM) models and residual hoop stresses from multiple balls simulation were compared with one ball and tapered mandrel simulations. Results showed that the use of three incremental balls significantly reduced the magnitude of non-conforming residual hoop stresses and the extension of these detrimental zone.

Parametric Electromagnetic Analysis of Radar-Based Advanced Driver Assistant Systems.

Efficient and optimal design of radar-based Advanced Driver Assistant Systems (ADAS) needs the evaluation of many different electromagnetic solutions for evaluating the impact of the radome on the electromagnetic wave propagation. Because of the very high frequency at which these devices operate, with the associated extremely small wavelength, very fine meshes are needed to accurately discretize the electromagnetic equations. Thus, the computational cost of each numerical solution for a given choice of the design or operation parameters, is high (CPU time consuming and needing significant computational resources) compromising the efficiency of standard optimization algorithms. In order to alleviate the just referred difficulties the present paper proposes an approach based on the use of reduced order modeling, in particular the construction of a parametric solution by employing a non-intrusive formulation of the Proper Generalized Decomposition, combined with a powerful phase-angle unwrapping strategy for accurately addressing the electric and magnetic fields interpolation, contributing to improve the design, the calibration and the operational use of those systems.

Design of personalized cancer treatments by use of optimal control problems: The case of chronic myeloid leukemia.

The advances in the mathematical explanation of the dynamics underlying treated cancer has opened the door to the mathematical design of optimal therapies. In parallel, the improvements and cost reductions in experimentation and data analysis techniques have made the formulation of personalized therapies possible. However, the design of cancer therapies making use of optimal control theory has not fully considered this possibility in detail. In this paper we contribute to the existing literature by analyzing the diverse alternatives that optimal therapy models offer to design personalized treatments. Taking as the starting point the Chronic Myeloid Leukemia (CML) optimal therapy model in [25], we design personalized optimal therapy models for patients with: CML; CML with intrinsic and/or induced resistance to the administered drug; CML and suffering high drug toxicity and/or allergy to the administered drug; and CML with presence of adverse factors. Along the paper we show that the clinical and medical applicability -the ultimate objective of this biomathematical research- of our proposed personalized models relies on the joint and proper use of the implemented calibration, simulation, and mathematical approaches and techniques. All the theoretical results generated by our personalized optimal therapy models are corroborated by clinical evidence.

The Vulvodynia Experience Questionnaire: Qualitative Development of a New Patient-Reported Outcome Measure for Vulvodynia.

INTRODUCTION: Vulvodynia is defined as vulvar pain of at least 3 months duration without a clear identifiable cause. There are currently no validated questionnaires that assess the experience of women with localized vulvodynia of the vestibule (vestibulodynia, previously known as vulvar vestibulitis) that meet the requirements of the Food and Drug Administration's Patient Reported Outcome (PRO) Guidance. AIM: To develop a new content-valid PRO assessment in accordance with the Food and Drug Administration's PRO guidance to assess the symptoms and impacts of localized vulvodynia. MATERIAL AND METHODS: Participants were recruited for concept elicitation interviews (ie, interviews with open-ended questions with the goal of eliciting volunteered data about the symptoms and impacts of vulvodynia). Participants were identified as having localized vulvodynia by clinicians who were experts in treating vulvar disorders. Eligibility was confirmed by the recruiting clinician, and informed consent was obtained; participants were then scheduled for in-person interviews. 25 participants were interviewed from United States (US). After concept elicitation interviews, the draft Vulvodynia Experience Questionnaire (VEQ) was developed based on the results. Cognitive interviews were conducted with 20 participants from US sites to assess the content validity of the VEQ (eg, interpretation and clarity of the items, relevance of concepts). The VEQ was further revised after cognitive interviews. All interviews were conducted face-to-face, audio-recorded, transcribed verbatim, anonymized, and analyzed using a qualitative data analysis software program. RESULTS: 17 unique symptoms and 32 unique impacts were reported during concept elicitation interviews. Pain (n = 25, 100%) and burning (n = 24, 96%) were the most frequently reported symptoms of localized vulvodynia, and negative impact on emotional well-being (n = 25, 100%) was the most frequently reported impact. After analysis, item generation, and cognitive interviews, the resulting VEQ v2.0 contains 3 parts (part 1, pain; part 2, associated symptoms; part 3, impacts) with a total of 25 items that measure the most frequently reported symptoms and impacts of localized vulvodynia. STRENGTH AND LIMITATIONS: The VEQ is a multidimensional assessment of the core symptoms and impacts of localized vulvodynia that, after additional psychometric testing including the ability to detect change, may be used in clinical trials to characterize the benefits of novel treatments. The VEQ requires additional testing to establish its cultural relevance and linguistic validity in other countries. CONCLUSION: The VEQ is a novel method of collecting information on localized vulvodynia symptoms and impacts that may be suitable for use in clinical trials after psychometric testing. Goldstein AT, Diez PMQ, Kapanadze S, et al. The Vulvodynia Experience Questionnaire: Qualitative Development of a New Patient-Reported Outcome Measure for Vulvodynia. J Sex Med 2020;17:2055-2066.

The effects of time valuation in cancer optimal therapies: a study of chronic myeloid leukemia.

BACKGROUND: The mathematical design of optimal therapies to fight cancer is an important research field in today's Biomathematics and Biomedicine given its relevance to formulate patient-specific treatments. Until now, however, cancer optimal therapies have considered that malignancy exclusively depends on the drug concentration and the number of cancer cells, ignoring that the faster the cancer grows the worse the cancer is, and that early drug doses are more prejudicial. Here, we analyze how optimal therapies are affected when the time evolution of treated cancer is envisaged as an additional element determining malignancy, analyzing in detail the implications for imatinib-treated Chronic Myeloid Leukemia. METHODS: Taking as reference a mathematical model describing Chronic Myeloid Leukemia dynamics, we design an optimal therapy problem by modifying the usual malignancy objective function, unaware of any temporal dimension of cancer malignance. In particular, we introduce a time valuation factor capturing the increase of malignancy associated to the quick development of the disease and the persistent negative effects of initial drug doses. After assigning values to the parameters involved, we solve and simulate the model with and without the new time valuation factor, comparing the results for the drug doses and the evolution of the disease. RESULTS: Our computational simulations unequivocally show that the consideration of a time valuation factor capturing the higher malignancy associated with early growth of cancer and drug administration allows more efficient therapies to be designed. More specifically, when this time valuation factor is incorporated into the objective function, the optimal drug doses are lower, and do not involve medically relevant increases in the number of cancer cells or in the disease duration. CONCLUSIONS: In the light of our simulations and as biomedical evidence strongly suggests, the existence of a time valuation factor affecting malignancy in treated cancer cannot be ignored when designing cancer optimal therapies. Indeed, the consideration of a time valuation factor modulating malignancy results in significant gains of efficiency in the optimal therapy with relevant implications from the biomedical perspective, specially when designing patient-specific treatments.

A New Prediction Method for the Ultimate Tensile Strength of Steel Alloys with Small Punch Test.

The load⁻deflection curve acquired from the Small Punch Test (SPT) is used to obtain the mechanical properties of materials using different correlation methods. The scattering level of these regressions tends to be high when a wide set of materials is analyzed. In this study, a correlation method based on a specific slope of the SPT curve was proposed to reduce scattering. Assuming the Ramberg⁻Osgood hardening law, the dependence of the SPT curve slope on the yield strength and the hardening coefficient is demonstrated by numerical simulations (FEM). Considering that the ultimate tensile strength could be obtained from the hardening coefficient, a response surface of the ultimate tensile strength with the yield strength and SPT curve slope, along with its equation, is presented for steel alloys. A summary of steel mechanical properties, based on the Boiler and Pressure Vessel Code (BPVC) and limited to yield strengths lower than 1300 MPa, is shown to select a set of experimental tests (tensile tests and SPTs) for which the range is completely covered. This experimental analysis validates the previous FEM analyses and the validity of the proposed correlation method, which shows more accurate correlations compared to the current methods.

Less common etiologies of exocrine pancreatic insufficiency.

Exocrine pancreatic insufficiency (EPI), an important cause of maldigestion and malabsorption, results from primary pancreatic diseases or secondarily impaired exocrine pancreatic function. Besides cystic fibrosis and chronic pancreatitis, the most common etiologies of EPI, other causes of EPI include unresectable pancreatic cancer, metabolic diseases (diabetes); impaired hormonal stimulation of exocrine pancreatic secretion by cholecystokinin (CCK); celiac or inflammatory bowel disease (IBD) due to loss of intestinal brush border proteins; and gastrointestinal surgery (asynchrony between motor and secretory functions, impaired enteropancreatic feedback, and inadequate mixing of pancreatic secretions with food). This paper reviews such conditions that have less straightforward associations with EPI and examines the role of pancreatic enzyme replacement therapy (PERT). Relevant literature was identified by database searches. Most patients with inoperable pancreatic cancer develop EPI (66%-92%). EPI occurs in patients with type 1 (26%-57%) or type 2 diabetes (20%-36%) and is typically mild to moderate; by definition, all patients with type 3c (pancreatogenic) diabetes have EPI. EPI occurs in untreated celiac disease (4%-80%), but typically resolves on a gluten-free diet. EPI manifests in patients with IBD (14%-74%) and up to 100% of gastrointestinal surgery patients (47%-100%; dependent on surgical site). With the paucity of published studies on PERT use for these conditions, recommendations for or against PERT use remain ambiguous. The authors conclude that there is an urgent need to conduct robust clinical studies to understand the validity and nature of associations between EPI and medical conditions beyond those with proven mechanisms, and examine the potential role for PERT.

Immunocytochemical stem cell markers can predict clinical stage of breast cancer.

We present a computational-statistical algorithm that, from data on the staining degree of immunocytochemical markers: i) evaluates the ability of the considered immuno-panel in predicting the breast cancer stage; ii) makes the accurate identification of breast cancer stage possible; iii) provides the best stage prognosis compatible with the considered sample; and iv) does so through the use of the minimum number of markers minimizing time and resource costs. After running the algorithm on two data sets [triple-negative breast cancer, (TNBC), and estrogen receptor-negative breast cancer, (ERNBC)], we conclude that EpCAM and ß1 integrin are enough to accurately predict TNBC stage, being ALDH1, CD24, CD61, and CK5 the necessary markers to exactly predict ERNBC stage.

Glucosa tetrasacárido como biomarcador diagnóstico de la enfermedad de Pompe: estudio en 35 pacientes / Tetra-saccharide glucose as a diagnostic biomarker for Pompe disease: A study with 35 patients

Fundamento y objetivos: La enfermedad de Pompe es un trastorno originado por la deficiencia de la enzima alfa glucosidasa ácida (GAA). En esta afección se produce un acúmulo de glucógeno lisosomal en diferentes tejidos, estando especialmente implicados los músculos esquelético y cardíaco. El diagnóstico de confirmación se realiza mediante identificación del déficit de GAA. Existen, además, otros biomarcadores diagnósticos secundarios, como la glucosa tetrasacárido (Glc4), que se muestra elevada en orina de estos pacientes. Así, con este trabajo queremos poner de manifiesto la utilidad de la Glc4 como biomarcador diagnóstico para la enfermedad de Pompe en sus diferentes formas de presentación, utilizando un método de high-performance liquid chromatography (HPLC, «cromatografía líquida de alta resolución») con detección ultravioleta (UV) adaptado para nuestro estudio. Pacientes y métodos: Hemos analizado un total de 75 individuos: 40 controles sanos y 35 pacientes diagnosticados de enfermedad de Pompe. Se han recogido muestras de orina de 24 h de todos ellos y se han determinado sus niveles de Glc4 mediante HPLC/UV. Resultados: La evaluación de la Glc4 urinaria muestra una gran capacidad de discriminación entre individuos sanos/enfermos. Además, los resultados obtenidos nos han permitido establecer el nivel de decisión o punto de corte más apropiado para la identificación de los enfermos. Coclusiones: Los niveles de Glc4 urinarios se encuentran elevados en los pacientes con enfermedad de Pompe, y aunque se encuentran incrementados en otras dolencias, la existencia de un déficit de GAA, junto a una clínica compatible, proporcionan una alta sensibilidad para el diagnóstico de esta grave enfermedad (AU)

Background and objectives: Pompe disease is a disorder originating from an acid alpha-glycosidase (AAG) enzyme deficiency. This disease produces an accumulation of lysosomal glycogen in different tissues, whereby the skeletal and heart muscles are especially involved. The established diagnosis is achieved through the identification of the AAG deficiency. There are also other secondary diagnostic biomarkers, such as tetra-saccharide glucose (Glc4), which shows high levels in the urine of these patients. In this study it is highlighted the usefulness of Glc4 as a diagnostic biomarker for Pompe disease in its different forms of presentation, using a high-performance liquid chromatography with ultraviolet detection (HPLC/UV) adapted to the study. Patients and methods: A total of 75 individuals have been analyzed: 40 healthy controls and 35 patients diagnosed with Pompe disease. Twenty-four hour samples of urine were collected from all of the patients and their Glc4 levels were determined by means of PLC/UV. Results: The evaluation of the urinary Glc4 shows a high discrimination ability between healthy/sick individuals. In addition, the results obtained have allowed to establish the most appropriate level of decision or cut-off point for the identification of sick people. Conclusions: Glc4 urinary levels are found to be high in patients suffering from Pompe disease and even though increased levels are also found in other conditions, the existence of a AAG deficiency together with a compatible clinical symptoms, prove very helpful for a correct diagnosis of this serious disease (AU)

[Tetra-saccharide glucose as a diagnostic biomarker for Pompe disease: a study with 35 patients]. / Glucosa tetrasacárido como biomarcador diagnóstico de la enfermedad de Pompe: estudio en 35 pacientes.

BACKGROUND AND OBJECTIVES: Pompe disease is a disorder originating from an acid alpha-glycosidase (AAG) enzyme deficiency. This disease produces an accumulation of lysosomal glycogen in different tissues, whereby the skeletal and heart muscles are especially involved. The established diagnosis is achieved through the identification of the AAG deficiency. There are also other secondary diagnostic biomarkers, such as tetra-saccharide glucose (Glc4), which shows high levels in the urine of these patients. In this study it is highlighted the usefulness of Glc4 as a diagnostic biomarker for Pompe disease in its different forms of presentation, using a high-performance liquid chromatography with ultraviolet detection (HPLC/UV) adapted to the study. PATIENTS AND METHODS: A total of 75 individuals have been analyzed: 40 healthy controls and 35 patients diagnosed with Pompe disease. Twenty-four hour samples of urine were collected from all of the patients and their Glc4 levels were determined by means of HPLC/UV. RESULTS: The evaluation of the urinary Glc4 shows a high discrimination ability between healthy/sick individuals. In addition, the results obtained have allowed to establish the most appropriate level of decision or cut-off point for the identification of sick people. CONCLUSIONS: Glc4 urinary levels are found to be high in patients suffering from Pompe disease and even though increased levels are also found in other conditions, the existence of a AAG deficiency together with a compatible clinical symptoms, prove very helpful for a correct diagnosis of this serious disease.

Osseointegrated implant rehabilitation of irradiated oral cancer patients.

PURPOSE: The aim of this study is to analyze implant survival in patients who received radiotherapy treatment for oral malignancies and in patients who had suffered mandibular osteoradionecrosis. MATERIALS AND METHODS: We reviewed retrospectively 225 implants placed in 30 patients who had received radiotherapy as part of the oncologic treatment. Radiation doses ranged between 50 and 70 Gy. 39 implants were placed after a combined treatment of radiotherapy and chemotherapy. Data referred to tumour type and reconstruction, presence of osteoradionecrosis, region of implant installation and type of prostheses were recorded. Survival rates were calculated with cumulative Kaplan-Meier survival curves and compared between different groups with a log-rank test. RESULTS: 152 osseointegrated implants were placed in patients who presented previous reconstruction procedure. Five patients developed osteorradionecrosis as a complication of the radiotherapy treatment. Once osteoradionecrosis had healed in these patients, 41 implants were installed. The overall 5 year survival rate in irradiated patients was 92.6%. Irradiated patients had a marginally significantly higher implant loss than non-irradiated patients. (p = 0.063). The 5 year survival rate in the osteoradionecrosis group was of 48.3% and in the non-osteoradionecrosis group 92.3%, with a statistically significant difference between both groups. (p = 0.002). CONCLUSION: Osseointegrated implants enhance oral rehabilitation in most irradiated patients, even being an acceptable option for patients who had suffered osteoradionecrosis. Totally implant supported prostheses are recommended after irradiation providing functional, stable and aesthetically satisfactory rehabilitation.

Solids and nutrients removals from the liquid fraction of swine slurry through screening and flocculation treatment and influence of these processes on anaerobic biodegradability.

A correct separation of solids from liquid fraction is crucial for a successful treatment of swine manure. For this reason an in-depth study of flocculant addition on different livestock wastewaters was carried out. Two flushed swine manure matrices, namely the mixture from nursery and feeder-to-finish pigs and the feeder-to-finish slurry alone, were tested for solids and nutrients removals from liquid fractions. The separation techniques applied were sieving and flocculation. A range of 80-200 ppm of polyacrylamide (PAM) followed by screening was employed in the case of flocculation treatment. The best results were observed when using the highest PAM dose in the matrix correspondent to the mixture of slurries. The removal rates in the liquid fraction were 73% for total solids, 87% for volatile solids, 98% for suspended total and volatile solids, 71% for chemical oxygen demand, 40% for total Kjeldahl nitrogen, and 34% for soluble phosphorus. Once the best PAM dose (120 ppm) was chosen, an anaerobic biodegradability study was performed in order to check the increase of methane production in the separated fractions by using the flocculant and the screen. The assay determined that the solid fractions biodegradability was constant at 79%. Meanwhile for the liquid fractions, an increase of 9% points was achieved with PAM-amendment when compared with 82% reached for the liquid fraction obtained by screening.

Grado de satisfacción de la población con los servicios de enfermería en un área de salud / Satisfaction degree of the population with the nursing services in a health area

Se realizó un estudio descriptivo retrospectivo en la población de Perea en el área de salud Policlínico Venegas teniendo en cuenta la visión que se tiene de la relación enfermera-paciente y de la función que realiza la enfermera en la comunidad. El objetivo de este trabajo fue demostrar el grado de satisfacción de la población con la labor de enfermería medida mediante una encuesta con un cuestionario de satisfacción . Se encontró que la atención de enfermería que se brinda en esta área y la relación enfermera-paciente que se establece satisfizo a un 68,5(por ciento) de la población. La mayoría de los pacientes que conformaron la muestra, 128 (93,8(por ciento) se mostró satisfecha con el indicador que midió la confianza en su enfermera, sin embargo, la eficiencia de su trabajo sólo alcanzó puntaje de satisfacción en 82 personas (63,1(por ciento). En la muestra estudiada el 82,3(por ciento) conoce a su enfermera desde hace 3 años. A pesar de que el trabajo de enfermería que se brinda en esta área de salud puede calificarse de bueno, es necesario reflexionar sobre los posibles aspectos de este trabajo que impide la satisfacción de la población en indicadores importantes como es la eficiencia, la amabilidad y la experencia(AU)

Grado de satisfacción de la población con los servicios de enfermería en un área de salud / Satisfaction degree of the population with the nursing services in a health area

Se realizó un estudio descriptivo retrospectivo en la población de Perea en el área de salud Policlínico Venegas teniendo en cuenta la visión que se tiene de la relación enfermera-paciente y de la función que realiza la enfermera en la comunidad. El objetivo de este trabajo fue demostrar el grado de satisfacción de la población con la labor de enfermería medida mediante una encuesta con un cuestionario de satisfacción . Se encontró que la atención de enfermería que se brinda en esta área y la relación enfermera-paciente que se establece satisfizo a un 68,5 por ciento de la población. La mayoría de los pacientes que conformaron la muestra, 128 (93,8 por ciento se mostró satisfecha con el indicador que midió la confianza en su enfermera, sin embargo, la eficiencia de su trabajo sólo alcanzó puntaje de satisfacción en 82 personas (63,1 por ciento). En la muestra estudiada el 82,3 por ciento conoce a su enfermera desde hace 3 años. A pesar de que el trabajo de enfermería que se brinda en esta área de salud puede calificarse de bueno, es necesario reflexionar sobre los posibles aspectos de este trabajo que impide la satisfacción de la población en indicadores importantes como es la eficiencia, la amabilidad y la experencia(AU)

He/she was carried out a retrospective descriptive study in the population of Perea in the area of health Policlínico Venegas keeping in mind the vision that one has of the nurse-patient relationship and of the function that the nurse carries out in the community. The objective of this work was to demonstrate the degree of the population's satisfaction with the infirmary work measured by means of a survey with a questionnaire of satisfaction. It was found that the infirmary attention that you toasts in this area and the nurse-patient relationship that he/she settles down satisfied to the population's 68,5 percent. Most of the patients that conformed the sample, 128 (93,8 percent was shown satisfied with the indicator that measured the trust in its nurse, the efficiency of its work reached puntaje of satisfaction however, only in 82 people (63,1 percent). In the studied sample 82,3 percent knows its nurse for 3 years. Although the infirmary work that you toasts in this area of health can be qualified of good, it is necessary to meditate on the possible aspects of this work that it impedes the population's satisfaction in important indicators as it is the efficiency, the kindness and the experencia(AU)

Coeficiente de operación (COP) del ciclo de carnot de bomba de calor endorreversible / Coefficient of performance of an endoreversible carnot heat pump cycle

Se desarrolló el modelo matemático correspondiente al Coeficiente de Operación (COP) del ciclo de Carnot para una bomba de calor endorreversible, aplicando el criterio de mínima generación de entropía. Este ciclo tiene como características principales ser internamente reversible y externamente irreversible. Las irreversibilidades externas están asociadas a los procesos de transferencia de calor debido a la diferencia de temperaturas entre la fuente térmica y el fluido de trabajo a baja temperatura, y a la diferencia de temperaturas entre el fluido de trabajo y el sumidero térmico a alta temperatura. También son causantes de las irreversibilidades externas los tiempos finitos de duración de los procesos de transferencia de calor y las conductancias térmicas finitas de los equipos de transferencia de calor (evaporador y condensador). Estas causas de irreversibilidades aparecen en el modelo matemático desarrollado y por esto se propone como nuevo modelo de comparación para las bombas de calor, en lugar del modelo clásico de Coeficiente de Operación de Carnot de bomba de calor reversible. Este nuevo modelo marca límites de operación más cercanos a las bombas de calor reales. El modelo obtenido viene a ser una contribución al desarrollo de la termodinámica endorreversible y se puede considerar una generalización, porque cuando se aplican las condiciones de reversibilidades internas y externas, se llega al mismo resultado que el clásico de Carnot.