Tailored Time-Temperature Transformation Diagram for IN718 Alloy Obtained via Powder Bed Fusion Additive Manufacturing: Phase Behavior and Precipitation Dynamic.

Experimental and computational approaches were used to study the microstructure of IN718 produced via powder bed fusion additive manufacturing (PBF-AM). The presence, chemical composition, and distribution of stable and metastable phases (γ'', δ, MC, and Laves) were also analyzed. The information obtained from the microstructural study was used to construct a tailored time-temperature transformation (TTT) diagram customized for additive manufacturing of IN718. Experimental techniques, including differential scanning calorimetry (DSC), scanning electron microscopy, energy dispersive X-ray spectroscopy, and electron backscatter diffraction (EBSD), were employed to establish the morphological, chemical, and structural characteristics of the microstructure. The Thermo-Calc software and a Scheil-Gulliver model were used to analyze the presence and behavior of phase transformations during heating and cooling processes under non-thermodynamic equilibrium conditions, typical of AM processes. Unlike conventional TTT diagrams of this alloy, the diagram presented here reveals that the precipitation of γ'' and δ phases occurs at lower temperatures and shorter times in AM-manufactured parts. Significantly, the superposition of γ'' and δ phase curves in the proposed diagram underscores the interdependence between these phases. This TTT diagram is a valuable insight that can help in the development of heat treatment processes and quality control for IN718 produced via PBF-AM.

Determination of TTT Diagrams of Ni-Al Binary Using Neural Networks.

The heat treatment of a metal is a set of heating and cooling cycles that a metal undergoes to change its microstructure and, therefore, its properties. Temperature-time-transformation (TTT) diagrams are an essential tool for interpreting the resulting microstructures after heat treatments. The present work describes a novel proposal to predict TTT diagrams of the γ' phase for the Ni-Al alloy using artificial neural networks (ANNs). The proposed methodology is composed of five stages: (1) database creation, (2) experimental design, (3) ANNs training, (4) ANNs validation, and (5) proposed models analysis. Two approaches were addressed, the first to predict only the nose point of the TTT diagrams and the second to predict the complete curve. Finally, the best models for each approach were merged to compose a more accurate hybrid model. The results show that the multilayer perceptron architecture is the most efficient and accurate compared to the simulated TTT diagrams. The prediction of the nose point and the complete curve showed an accuracy of 98.07% and 86.41%, respectively. The proposed final hybrid model achieves an accuracy of 96.59%.

Early diagnosis of anastomotic leakage in colorectal surgery: prospective observational study of the utility of inflammatory markers and determination of pathological levels.

Procalcitonin (PCT) and C-Reactive Protein (CRP) are acute-phase reactants that indicate the presence and severity of an infection. The aim of this study was to verify the utility of CRP and PCT as tools for early diagnosis of anastomotic leakage (AL) in patients undergoing elective colorectal surgery. A prospective observational study including 95 patients undergoing elective colorectal surgery with anastomosis, where patients were divided into two groups according to whether or not AL happened. Different variables were compared using a uni- and multivariate analyses to identify the risk factors for AL. Receiver Operating Characteristic (ROC) curves were added to establish a cut-off point for CRP and PCT. The inflammatory marker levels were analysed in other complications different from AL. AL was detected in 11 patients (14%), 7 required an emergency reoperation. The overall morbidity rate was 42.1% and the mortality was 3.2%. In the univariate study, increased CRP on days 3 and 5, male sex and intraoperative complications were significantly associated with AL. In the multivariate study, CRP on day 5 was the only factor related to AL. AUC at ROC curves showed that CRP results ≥ 15.3 mg/dL on day 3 and 9.1 mg/dL on day 5 were predictors of AL. Normal CRP and PCT values had a high negative predictive value. CRP on postoperative day 5 is a reliable marker for early detection of anastomotic leakage in colorectal surgery. Both CRP and PCT on days 3 and 5 have a high negative predictive value.Trial registration: The study has been registered at ClinicalTrials.gov. Code: NCT04632446.

Utilización de las tecnologías de la información y comunicación (TIC) en estudiantes universitarios paraguayos / Use of information and communication technologies (ICT) in Paraguayan university students

Introducción: Las nuevas tecnologías son aquellos medios de comunicación que van surgiendo de los avances de la electrónica y herramientas conceptuales. El impacto de TIC en la investigación en Paraguay no es muy evidente, dejando la investigación en vías de desarrollo. Objetivos: Establecer los factores tecnológicos y educativos más frecuentes e influyentes de los estudiantes de la Universidad Nacional de Asunción. Materiales y métodos: Estudio observacional descriptivo, corte transversal, muestreo no probabilístico por conveniencia, entre abril a mayo del 2018 en la Universidad Nacional de Asunción. Se consideró una p<0,05 como significativa. Resultados: Edades entre 18 a 30 años (22,04±2,25); sexo femenino 61,1 % (210); Gran Asunción 56,9 % (196). Factores tecnológico- educativos más frecuentes fueron no poseer grupo de estudio en 79,9 % (275); inglés básico con 35,5 % (122). Pertenencia de computadora portátil (89 %), internet inalámbrico (79 %), teléfono inteligente (92 %). 10,19 horas promedio de acceso a internet diario. Uso de Google, Google Académico y SciELO. Conclusión: Es necesario demostrar la relevancia de la incorporación de las TIC en la educación de los universitarios del área de la salud y su beneficio del desarrollo personal y profesional. Se señala la importancia de la educación a nivel regional y local.

Introduction: New technologies are those sources of communication that are emerging from advances in electronics and conceptual tools. The impact of ICT on research in Paraguay is not very evident, leaving research under development. Objectives: To establish the most frequent and influential technological and educational factors of the students of the Universidad Nacional de Asunción. Materials and methods: Descriptive observational study, cross-sectional, non-probabilistic sampling for convenience, between April to May 2018 at the Universidad Nacional de Asunción. A p <0.05 was considered significant. Results: Ages between 18 to 30 years (22.04 ± 2.25); female sex 61.1% (210); Great Asunción 56.9% (196). The most frequent technological-educational factors were not having a study group in 79.9% (275); Basic English with 35.5% (122). Ownership of laptop (89%), wireless internet (79%), smartphone (92%). 10.19 average hours of daily internet access. Use of Google, Google Scholar and SciELO. Conclusion: It is necessary to demonstrate the relevance of the incorporation of ICT in the education of university students in the health area and its benefit for personal and professional development. The importance of education at regional and local level is pointed out.

Population-based screening improves histopathological prognostic factors in colorectal cancer.

INTRODUCTION: Diagnosis of colorectal cancer (CRC) based on clinical symptoms is usually established in its advanced stages. One strategy for reducing mortality is the early detection and removal of preneoplastic and initial neoplastic lesions, even before the first symptoms appear, by means of population-based screening campaigns. The aim of the present study is to determine whether CRC diagnosed via a screening campaign has more favourable histopathological prognostic factors than when diagnosed in the symptomatic phase. MATERIAL AND METHODS: The prospective study of all the patients undergoing programmed CRC surgery at the JM Morales Meseguer Hospital (Spain) is between 2004 and 2010. The patients were divided into two groups: one diagnosed from clinical symptoms and one through a screening campaign. The following factors were compared: tumour size; degree of tumour invasion of the wall; lymph node, perineural and lymphovascular involvement; tumour stage; and grade of differentiation. RESULTS: Compared to the symptomatic group, the screen-detected patients had smaller-sized tumours (lesions of less than 5 cm in 84 vs 69.55%, p < 0.001), a lower degree of colorectal wall invasion (T0-1 in 36 vs 9.02%, p < 0.001), less lymph node involvement (N0 in 72 vs 58.76%, p > 0.05), less vascular invasion (7.20 vs 15.22%, p = 0.79) and less perineural invasion (6.4 vs 20.70%, p < 0.001). The TNM staging in the screening group was lower than in the symptomatic group (stage 0-1 in 50.40 vs 18.58%, p < 0.001). CONCLUSIONS: CRC diagnosed through a population-based screening programme presents more favourable histopathological characteristics than that diagnosed from the appearance of symptoms.

Subclavian central venous catheter, complications at insertion / Catéter venoso central subclavio, complicaciones a la inserción

Background: Central Venous Catheters (CVC) are used as a tool in critically ill patients requiring hemodynamic monitoring and vasopressor support, as well as in stable patients requiring parenteral nutrition or chemotherapy. Placement of a CVC subclavian (CVCs) can present severe complications, even fatal. The aim of the present study was to determine the success of the placement of CVCs without ultrasonographic guidance and the number and type of complications associated with insertion. of these. Methods: In this retrospective cohort study we included all patient who were submitted to CVCs at the Hospital de Especialidades del Centro Médico Nacional Siglo XXI. The variables studied were: medical indication for the placement, insertion site, duration, withdrawal motive and if there were complications type number and management of these. Results: 283 patients aged 16-95 years were studied. Fifty-five percent of the patients had already had a catheter placed during a previous hospitalization. In 45% of the patients was the first placement, the antecedent of a previous placement did not increase the complications. The indications for the CVCs were: NPT, preoperative use, severe patients, chemotherapy, inability to channel, and plasmapheresis. Conclusions: Placement of a subclavian central venous catheter by trained personnel in patients without risk factors and even without ultrasonographic support is safe and effective, with a success rate of close to 100% in placement, severe complications below 2%, and zero mortality. If the attempts are reduced to two punctures the morbidity can be reduced to almost zero.

Introducción: Los catéteres venosos centrales (CVC) son utilizados tanto en pacientes gravemente enfermos que ameritan monitorización hemodinámica y apoyo vasopresor, como en pacientes estables que requieren nutrición parenteral o quimioterapia. La colocación de un CVC subclavio (CVCs) puede presentar complicaciones severas incluso mortales. El objetivo del presente estudio fue determinar el éxito de la colocación de CVCs sin guía ultrasonográfica y el número y tipo de complicaciones asociadas a la inserción de estos. Métodos: Estudio de cohorte retrospectivo, que incluyó a todos los pacientes a los cuales se les colocó un CVCs en el Hospital de Especialidades del Centro Médico Nacional Siglo XXI. Las variables estudiadas fueron: indicación médica para la colocación, sitio de inserción, duración, motivo de retiro y si se presentaron complicaciones. Resultados: Se estudió a un total de 283 pacientes de 16 a 95 años. En el 45% de los pacientes fue la primera colocación, el antecedente de una colocación previa no aumento las complicaciones. Las indicaciones para el CVCs fueron: nutrición parenteral, uso prequirúrgico, pacientes graves, quimioterapia, incapacidad para canalizar y plasmaféresis. Conclusiones: La colocación de un CVCs por personal capacitado en pacientes sin factores de riesgo y aun sin apoyo ultrasonográfico es segura y eficaz, con complicaciones graves menores al 2% y sin mortalidad. Si los intentos se reducen a dos punciones, la morbilidad puede reducirse aún más.

Uso de café, chicle y gastrografín en el manejo del íleo postoperatorio: revisión de la evidencia actual / The use of coffee, chewing-gum and gastrograffin in the management of postoperative ileus: A review of current evidence

El íleo paralítico es una de las principales complicaciones del postoperatorio. Con la introducción de los protocolos fast-track para acelerar la recuperación, han aparecido nuevas medidas, como la toma temprana de café , mascar chicle y el gastrografín. Para conocer mejor estas actuaciones, se ha realizado un resumen de la evidencia actual, utilizando las bases de datos de MEDLINE, Cochrane Database of Systematic Reviews, Web of Science y SCOPUS. Los términos empleados fueron «postoperative ileus» AND («definition» OR «epidemiology» OR «risk factors» OR «management»). Se han seleccionado 44 artículos, de los cuales 9 son revisiones sistemáticas, 11 revisiones narrativas, 13 ensayos clínicos aleatorizados, 6 estudios observacionales y los 5 restantes cartas científicas, hipótesis, etc. Se ha visto que existe poca literatura acerca del tema, que los estudios son heterogéneos (con disparidad en los resultados) y se centran en cirugía colorrectal y ginecológica. Se necesitan nuevos estudios, preferentemente ensayos clínicos aleatorizados, que esclarezcan la utilidad de estas medidas

Postoperative ileus is one of the main complications in the postoperative period. New measures appeared with the introduction of «fast-track surgery» to accelerate recovery: coffee, chewing gum and gastrograffin. We performed a summary of current evidence, reviewing articles from MEDLINE, Cochrane Database of Systematic Reviews, ISI Web of Science, and SCOPUS databases. Employed search terms were «postoperative ileus» AND («definition» OR «epidemiology» OR «risk factors» OR «Management»). We selected 44 articles: 9 systematic reviews 11 narrative reviews, 13 randomized clinical trials, 6 observational studies, and the remaining 5 scientific letters, assumptions, etc. There is little literature about this topic, studies are heterogeneous, with disparity in the results. In addition, they only focus on colorectal and gynecological surgery. New high-quality studies are needed, preferably randomized clinical trials, in order to clarify the usefulness of these measures

The use of coffee, chewing-gum and gastrograffin in the management of postoperative ileus: A review of current evidence. / Uso de café, chicle y gastrografín en el manejo del íleo postoperatorio: revisión de la evidencia actual.

Postoperative ileus is one of the main complications in the postoperative period. New measures appeared with the introduction of «fast-track surgery¼ to accelerate recovery: coffee, chewing gum and gastrograffin. We performed a summary of current evidence, reviewing articles from MEDLINE, Cochrane Database of Systematic Reviews, ISI Web of Science, and SCOPUS databases. Employed search terms were «postoperative ileus¼ AND («definition¼ OR «epidemiology¼ OR «risk factors¼ OR «Management¼). We selected 44 articles: 9 systematic reviews 11 narrative reviews, 13 randomized clinical trials, 6 observational studies, and the remaining 5 scientific letters, assumptions, etc. There is little literature about this topic, studies are heterogeneous, with disparity in the results. In addition, they only focus on colorectal and gynecological surgery. New high-quality studies are needed, preferably randomized clinical trials, in order to clarify the usefulness of these measures.

Increased survival and decreased recurrence in colorectal cancer patients diagnosed in a screening programme.

INTRODUCTION: Population-based screening programmes for colorectal cancer (CRC) allow an early diagnosis, even before the onset of symptoms, but there are few studies and none in Spain on the influence they have on patient survival. The aim of the present study is to show that patients receiving surgery for CRC following diagnosis via a screening programme have a higher survival and disease-free survival rate than those diagnosed in the symptomatic stage. MATERIAL AND METHODS: Prospective study of all the patients undergoing programmed surgery for CRC at the JM Morales Meseguer Hospital in Murcia (Spain) between 2004 and 2010. The patients were divided into two groups: (a) those diagnosed through screening (125 cases); and (b) those diagnosed in the symptomatic stage (565 cases). Survival and disease-free survival were analysed and compared for both groups using the Mantel method. RESULTS: The screen-detected CRC patients show a higher rate of survival (86.3% versus 72.1% at 5 years, p<0.05) and a lower rate of tumour recurrence (73.4% versus 88.3% at 5 years, p<0.05). CONCLUSIONS: Population-based screening for CRC is an effective strategic measure for reducing mortality specific to this neoplasia.

Malignant degeneration of rectal endometriosis.

BACKGROUND: Endometriosis is a relatively common disease among women with child-bearing potential, and rare before puberty or following menopause. It consists of the presence of hormone-responsive endometrium outside the endometrial cavity. CASE REPORT: We report the case of a patient with a rectal lesion, initially approached as a primary rectal malignancy, where histopathology eventually revealed an adenocarcinoma arising from endometrial tissue in the colonic wall. DISCUSSION: Endometriosis has an estimated rated of 10-20%. Sites may be split up into two larger categories - gonadal and extragonadal. The frequency of extragonadal endometriosis in the bowel is estimated to involve 3%-37% of women with pelvic endometriosis, and most lesions are found in the sigmoid colon and rectum. The malignant transformation of endometriotic lesions is estimated between 0.3% and 1% of cases. The gold standard in the diagnosis of intestinal endometriosis is exploratory laparotomy and the pathological study of specimens. Adjuvant radiotherapy and chemotherapy, although used for some patients, have not proven effective.

Degeneración maligna de endometriosis de recto / Malignant degeneration of rectal endometriosis

INTRODUCCIÓN: la endometriosis es una patología relativamente frecuente en mujeres en edad fértil y poco prevalerte en mujeres prepúberes o postmenopáusicas. CASO CLÍNICO: presentamos el caso clínico de una mujer de 57 años, con antecedentes de histerectomía y doble anexectomía por endometriosis ovárica, diagnosticada de neoplasia de recto T3N1. Se realizó neoadyuvancia preoperatoria y resección anterior baja, sin complicaciones. La anatomía patológica describía infiltración de la pared rectal por adenocarcinoma pobremente diferenciado de origen ginecológico. DISCUSIÓN: la endometriosis tiene una prevalencia estimada del 10-20% y su lugar de aparición puede ser variado, tanto gonadal como extragonadal. La frecuencia de endometriosis extragonadal de localización intestinal se estima en un 3-37% de mujeres con endometriosis pélvica, y de estas la mayoría se localizan en colon sigmoide y recto. La transformación maligna de un foco de endometriosis se estima entre el 0,3 y el 1%. El gold estándar para el diagnóstico es la resección y estudio histológico. La radioterapia y quimioterapia adyuvante todavía no ha demostrado su clara utilidad

BACKGROUND: Endometriosis is a relatively common disease among women with child-bearing potential, and rare before puberty or following menopause. It consists of the presence of hormone-responsive endometrium outside the endometrial cavity. CASE REPORT: We report the case of a patient with a rectal lesion, initially approached as a primary rectal malignancy, where histopathology eventually revealed an adenocarcinoma arising from endometrial tissue in the colonic wall. DISCUSSION: Endometriosis has an estimated rated of 10-20%. Sites may be split up into two larger categories - gonadal and extragonadal. The frequency of extragonadal endometriosis in the bowel is estimated to involve 3%-37% of women with pelvic endometriosis, and most lesions are found in the sigmoid colon and rectum. The malignant transformation of endometriotic lesions is estimated between 0.3% and 1% of cases. The gold standard in the diagnosis of intestinal endometriosis is exploratory laparotomy and the pathological study of specimens. Adjuvant radiotherapy and chemotherapy, although used for some patients, have not proven effective

[Presacral tumor as a differential diagnosis of recurrent pilonidal sinus]. / Tumor presacro como diagnóstico diferencial del sinus pilonidal recidivado.

BACKGROUND: Retrorectal or presacral space is occupied during embryological stem cell development and therefore may contain a heterogeneous group of tumors. CLINICAL CASE: We report the case of a 22-year-old male with a pilonidal cyst operated due to recurrent pilonidal sinus cyst. Final diagnosis after pelvic computed tomography is large retrorectal cystic tumor and magnetic resonance diagnosis of a presacral cystic compatible wtih germ cell tumor. The tumor was removed surgically through the abdomen and diagnosis of cystic teratoma was established. CONCLUSION: Retrorectal tumors are rare lesions whose presence must be ruled out in case of recurrent sinus.

Antecedentes: durante el desarrollo embriológico, el espacio retrorrectal o presacro está ocupado por células pluripotenciales y, por tanto, puede contener un grupo heterogéneo de tumores. Caso clínico: se comunica el caso de un paciente masculino de 22 años de edad, intervenido de sinus pilonidal recidivado. Con estudios de tomografía computada de pelvis y resonancia magnética nuclear se sospechó la existencia de un tumor quístico presacro compatible con tumor germinal; la lesión se extirpó quirúrgicamente por vía abdominal y se estableció el diagnóstico definitivo de teratoma quístico. Conclusiones: los tumores retrorrectales son lesiones poco habituales que es necesario descartar en caso de sinus recidivantes.

Single-port transanal endoscopic microsurgery: a developing technique.

INTRODUCTION: Transanal endoscopic microsurgery is a widely used and valid technique with established indications. However, the cost of surgical anoscopes is not available in all centers. Many authors have described transanal resection of rectal tumors through a single laparoscopy port such as the SILS system. MATERIALS AND METHODS: We analyzed 5 cases of patients undergoing transanal resection with an SILS device. The clinical, surgical, and oncological data were assessed. RESULTS: The median distance to the anal margin was 7.2 cm (range, 5 to 10 cm) and median tumor size was 3 cm (range, 1 to 6 cm). Median operating time was 75 minutes (range, 60 to 120 min). A postsurgical rectorrhagia occurred in 1 of the case. Two cases were adenocarcinoma, 2 were adenomas, and the other was a mucosa without any tumor remnants. The margins were negative in all cases. CONCLUSIONS: Transanal resection of rectal tumors using the SILS technique is a feasible procedure. Longer series and prospective studies are necessary.

Sobre la productividad científica de los médicos residentes de cirugía general y digestiva / Scientific productivity of general and digestive surgery residents

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Infarto esplénico masivo como debut de hemoglobinopatía S / Massive splenic infarction leading to sickle cell disease

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Estimulación de raíces sacras para el dolor anal intratable / Sacral root stimulation for untreatable anal pain

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