bluuebunny/crossref_metadata_2025 huggingface dataset:
Perfil de salida de la Escuela de Arte Escénico, reflexionando sobre su misión
Authors: Hall Fernández Wendy
Published: July 2021

This article describes a research process with the pedagogical aim of delving into the exit profile of graduates from the School of Performing Arts of Universidad Nacional, Costa Rica as a first approach to reflecting on and analyzing the school’s mission statement in terms of training professionals and the roles they can play after completing the major or graduating from it. Therefore, this research is focused on determining the employment situation of the population who completed the major or graduated from it. The research was developed during the period of 2017-2018, and it was systematized in 2019 as part of the pre-major project of the school. This process was carried out in a participatory way with the people who are current students, graduates, and staff from the School of Performing Arts, thereby following a reflection process on theater pedagogy which began in 2013 and continues to the present.
El tiempo de la niñez. Discurso tutelar y criminalidad en Uruguay (1905-1934)
Authors: Fessler Daniel
Published: July 2021

The purpose of this paper is to inquire about the treatment of a sector of childhood, children who were identified as minors, considering the preliminary period of the Children's Code (1934). It is based on the investigation of legal and institutional changes that heralded a path towards specialization, recognized in Uruguay since 1905.The present article aims to discuss the omnipresence assigned to a tutelary discourse of child protection, analyzing the role of the concern for their participation in the increase rate of criminality. That concern was frequently overlooked in the face of the image of a paternal assistance that guided the normative and administrative transformations. This idea, on the other hand, still serves as a reference for the proposals of harder laws and tougher punishments. In the text we can find the records of examination into police memories, judicial files, projects, and chronicles which testify on how children were viewed as integral part in the changing reality of crime. The study accounts for a proposal that proclaimed a care model without renouncing control of the minors, a part of the population regarded as responsible for the criminal progression.
Comentario del libro: Una mirada histórica al bienestar rural argentino. Debates y propuestas de análisis, de Alejandra de Arce y Alejandra Salomón (compiladoras)
Authors: Rossi Ignacio Andrés
Published: July 2021

A recently published book produced by the Center for Studies of Rural Argentina of the National University of Quilmes (UNQ), Argentina, is discussed. This text contains a set of social studies of rural Argentina faced from multiple disciplinary perspectives: state formations and their impact on social evolution, the role of schools and health in peri-urban spaces, housing and industries in the economies regional, among others. The proposal becomes enriching for Latin American rural spaces as different theoretical and methodological tools are offered that can contribute to the development of this type of analysis in the region. The understanding of spaces and social problems becomes a fundamental tool to think about long-term solutions after the rural transformations developed in the last quarter of the century. The social sciences play a major role in this endeavor.
Reseña del libro: El Caribe: origen del mundo moderno, de Consuelo Naranjo Orovio, Mª Dolores González-Ripolll Navarro, María Ruiz del Árbol Moro (editoras)
Authors: Herrera Cuarezma Miguel Ángel
Published: July 2021

This bibliographic review of the book The Caribbean: origin of the modern world seeks to show, within the canons of the Journal of History, the importance of the historical processes developed in the Caribbean since 1492, and that our societies have experienced up to the present day, as well as their particular importance in the teaching of citizenship education in social studies, middle education. This especially because of the problems that derive from this history: racism as a form of condemnation to the permanent social exclusion of the most impoverished sectors of our societies.
Derechos humanos, guerra, posguerra y memoria en El Salvador: Sobre la vida y la obra académica de Ralph Sprenkels
Authors: Melara Minero Lidice Michelle , Menjívar Ochoa Mauricio
Published: July 2021

Dutch born anthropologist and historian Ralph Sprenkels, died unexpectedly in September 2019. Sprenkels devoted most of his research to understanding and explaining the conflict and post-war in El Salvador. This article describes the journey of how Sprenkels became linked to El Salvador and the impact this had on his life. He became a human rights activist, and later, dedicating himself to the investigation of postwar political polarization, to the study of memory and transitional justice, as well as one of the most important revolutionary movements in Latin America: the FMLN. In this sense, the article provides a general account of his work, which concludes that Sprenkel’s academic work constitutes a significant contribution to the understanding of Salvadorian reality, making significant theoretical contributions to new research.
Impresión como Historia: José Daniel Carmona sobre los Maleku
Authors: Frajman Eduardo
Published: July 2021

Este ensayo explora la situación del pueblo indígena Maleku en Costa Rica, a finales del siglo diecinueve. Su enfoque es impresionista, basado en la crónica de la última visita a los Maleku realizada por el Obispo Bernardo Augusto Thiel, escrita por el Presbítero José Daniel Carmona. El ensayo conecta las remembranzas de Carmona con la concepción de América desarrollada por el historiógrafo Edmundo O’Gorman.
Los métodos de la educación sexual en Costa Rica: Normalidad sexual, Guerra Fría e institucionalización (1968-1970)
Authors: Jiménez Bolaños José Daniel
Published: July 2021

Este artículo tiene por objetivo examinar las primeras discusiones que se desarrollaron en el marco de la institucionalización del Plan Nacional de Educación Sexual en Costa Rica, vinculadas con el tema de los métodos necesarios para implementar dicha materia en el currículo educativo. Primeramente, se hace un análisis del contexto nacional y global en el cual se instalan estas discusiones, con énfasis en la influencia de la Guerra Fría y la revolución sexual de los años sesenta. Luego, se detallan las diferentes instituciones que se fueron creando durante el periodo y que tuvieron un papel central en el Plan Nacional, para finalizar con un análisis de los diferentes métodos en disputa, mediante la revisión de los discursos de las principales autoridades educativas del país. Siguiendo a Foucault, se concluye que, a pesar de las críticas a las que fueron sometidos el método del silencio y el método profiláctico, no se impugnó la idea de una normalidad sexual en las aulas.
Historia de las relaciones diplomáticas Costa Rica-Perú durante el período de la Campaña Nacional contra los Filibusteros (1856-1857): el caso del empréstito peruano
Authors: Mora-Ugalde Sara , Monge-Blanco Silvia , Mora-Rodríguez Adriana
Published: July 2021

This article aims to study the diplomatic history between Costa Rica and Peru during the campaign against the filibusters, particularlythe Peruvian loan case. This study included diplomatic correspondence and some works of Costa Rican and Peruvian authors in which this subject was analyzed. By using discourse analysis, categories were established to identify the main reasons why this South American country conceded a loan to Costa Rica. These reasons were expressed mainly by the Peruvian Minister Pedro Gálvez, showing an evolvement in the justifications for the loan, starting with the characterization of Costa Rica, continuing with issues about the armed conflict at that time, to finally expose qualities attributed to Peru that reinforced the convenience of securing help to the Central American country.
Las relaciones exteriores de Costa Rica hacia Turquía: un análisis desde sus orígenes a su situación actual
Authors: Solís Javier Johanning , Moya-Mena Sergio Iván
Published: July 2021

Costa Rica’s foreign relations with its non-traditional partners has been scarcely studied, resulting in a lack of knowledge about how Costa Rica conducts its foreign policy with these partners from all around the world. This research aims to partially fill this gap by analyzing the origin and subsequent development of the Costa Rican foreign relations towards Turkey. Starting in 1950, the relations were mostly political, constrained by the Cold War context. Later on, specially by Turkish interests on promoting its exports and increasing influence globally, the relations intensified during the second half of the first decade of the twenty first century. By 2014, both countries stablished permanent diplomatic missions. Since then, the relations have been fluctuant, driven mostly by economic and trade interests from both sides, where Costa Rica looks for new markets for its products, international cooperation funds and support to become member of the Organization for Economic Cooperation and Development; while Turkey is mostly interested in negotiating a Free Trade Agreement with Central America, benefiting then its positive trade balance with Costa Rica. Recent trade disagreements regarding banana production in Turkey, one of the main export products of Costa Rica, and the import of steel from Turkey, has slowed down the bilateral relationship.
Reseña del libro: Krastev, I. y Holmes, S. (2019). La luz que se apaga. Cómo occidente ganó la Guerra Fría pero perdió la Paz. Barcelona: Libros Debate.
Authors: Abreu-Colombri José Antonio
Published: July 2021

"La luz que se apaga" focuses the attention on the period right after the ending of the Soviet Union which influenced the transformation of collective thinking. Neoliberalism, despite becoming the dominant philosophical idea with the victory of the capitalist systems, could not prevail as the only ideological system in the post-Cold War world.
Effect of laminated structure design on physical and mechanical properties of laminated bamboo sliver lumber
Authors: Deng Jianchao , He Lingxianzi , Zhu Anming
Published: July 2021

Laminated structure design is one of the significant factors that affect the physical and mechanical properties of laminated bamboo sliver lumber (LBSL). Eight patterns of assembly for 5-ply LBSL (LLLLL, LLVLL, LVLVL, LVVVL, LLV’LL, LV’LV’L, LVV’VL, and LV’VV’L) were prepared in this study; L represents one horizontal layer of the bamboo-sliver veneer, V represents the layer that is vertical to L, and V’ represents the layer at an angle of 45 ° to the L (or V). The objective of this study was to investigate the exclusive effect of the laminated structure design on the performance of the LBSL, rather than the multiple effect of the number of plies, chemical components, matter content, etc. The results indicated that the bending modulus of elasticity (MOE), bending modulus of rupture (MOR), impact strength, tensile strength, and compressive strength decreased with the decrease in number of layers of ply, for the following levels of L-ply: 5-L-ply (LLLLL), 4-L-ply (LLVLL, and LLV’LL), 3-L-ply (LVLVL, and LV’LV’L), and 2-L-ply (LVVVL, LVV’VL, and LV’VV’L). For the LBSL with the same number of L layers, those which had more V’ layers possessed better properties, due to the action of the parallel component of the force of the V’ layer. The values of absorption swelling rate, breaking strength, and displacement indicated that the LBSL with higher structural complexity achieved poorer underwater dimensional stability, but better single-bolted connection performance.
Discrete wavelet transformation and genetic algorithm – back propagation neural network applied in monitoring woodworking tool wear conditions in the milling operation spindle power signals
Authors: Dong Weihang , Guo Xiaolei , Hu Yong , Wang Jinxin , Tian Guangjun
Published: July 2021

Tool wear conditions monitoring is an important mechanical processing system that can improve the processing quality of wood plastic composite furniture and reduce industrial energy consumption. An appropriate signal, feature extraction method, and model establishment method can effectively improve the accuracy of tool wear monitoring. In this work, an effective method based on discrete wavelet transformation (DWT) and genetic algorithm (GA) – back propagation (BP) neural network was proposed to monitor the tool wear conditions. The spindle power signals under different spindle speeds, depths of milling, and tool wear conditions were collected by power sensors connected to the machine tool control box. Based on the feature extraction method, the approximate coefficients of spindle power signal were extracted by DWT. Then, the extracted approximate coefficients, spindle speeds, depths of milling, and tool wear conditions were taken as samples to train the monitoring model. Threshold and weight of BP neural network were optimized by GA, and the accuracy of monitoring model established by the GA – BP neural network can reach 100%. Thus, the proposed monitoring method can accurately monitor tool wear conditions with different milling parameters, which can achieve the purpose of improving the processing quality of wood plastic composite furniture and reducing energy consumption.
Analysis of neodymium-doped yttrium-aluminum-garnet laser and experimental prospects for cutting micro-thin black walnut veneers in industry
Authors: Doumbia Bakary S. , Yang Chunmei , Ma Yan , Jiang Ting , Li Xiang , Yu Wenji
Published: July 2021

By structurally and practically analyzing the use of Nd: YAG laser for cutting black walnut veneer, this study considered practical and environmental concerns regarding the global warming protection measures. A numerical model of laser wood veneer cutting was based on the relation between process parameters and the material thickness. A pulsed Nd: YAG was used to cut black walnut veneer of 0.3 mm thickness under different machining conditions regarding laser power and cutting speed to study the cut kerf width. An analysis of variance was conducted to test the significance of machining parameters. The parameters studied were laser power, cutting speed, kerf width, cut surface, safety, and eco-friendliness. The results showed that the kerf width decreased significantly with increased cut speed and, inversely, by laser output power. An efficient cut with a narrow kerf, clean and smooth, with less burn, was possible at laser cutting speeds of 2.5, 5.0, and 5.5 mm/s with kerf widths of 0.544, 0.69, 0.62 mm, respectively. As multiple factors affect the micro-thin wood laser cutting process, finding the optimal process parameters is crucial for successful machining with no burn effect.
Cast steel 4Kh4N5M4F2 for hot pressing mold of copper M1 and aluminum alloy AK7ch
Authors:   Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Sydorchuk O. M.
Published: July 2021

The mode of quenching and tempering of the investigated 4Kh4N5M4F2 steel with controlled austenitic transformation during operation is developed. The optimal temperature regime of hardening of the investigated steel is 1100 ± 5 °C and with increasing hardening temperature (above 1100 °C) the size of austenitic grain increases and the recrystallization process is intensive, which leads to a decrease in strength. It is recommended to carry out low-temperature tempering at temperatures of 190 ± 10 °C of hardened steel to reduce internal stresses. It has been established that tempering of hardened steel is necessary by cooling in the air. The optimum temperature mode of steel tempering is 590 ± 5 °C. The analysis of the structural state of the investigated steel after hardening and tempering (isothermal holding for two and four hours) is carried out. It was established that the maximum operating temperature of the die for hot pressing of copper (grade M1) can reach up to 650 °C. It is shown that the die of the studied steel is able to work at (extreme) temperature operating conditions of 625–650 °C. Heat resistance decrease (below 40 HRC) and softening occur in steel above the higher operating temperature (>650 °C). A pilot test was carried out on a die tool made of 4Kh4N5M4F2 steel (non-forging technology) for hot pressing of an aluminum alloy of the AK7ch grade, which showed the same service properties at the level of 4Kh5MF1S steel (grade H13, USA), which was subjected to ingot hot deformation (forging) with working surface nitride hardening to a depth of 300 microns. Keywords: die steel, thermal treatment, hot deformation, hardness, toughness.
Study of wetting and impregnation kinetics of oxide fibers with lead melts and its alloys
Authors:   Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krasovskyy V. P. , Krasovskaya N. A. ,   Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine
Published: July 2021

The effect of metal coverings on wetting of oxide fibers by lead, bismuth, tin-lead-bismuth-cadmium alloy in vacuum 2·10-3 Pa in the temperature range 400–600 oC was studied by the sessile drop method using the capillary purification method of melt. Oxide fibers plaits that have been placed on a silicon oxide substrate as wetting substrates used. Titanium and nickel powders were used as metal coatings. There is no wetting. The contact angles are close to or greater than 90 degrees and only in the case of the lead-titanium melt system at 600 oC the value of the angle is 15, respectively. The use of a dropper allows separate heating of the melt and the substrate, capillary and thermo vacuum cleaning of the melt, as well as thermo vacuum cleaning of the coatings surface. This is a model scheme of the impregnation process of non-metallic frames with matrix melts in the manufacture of composite materials by spontaneous free impregnation. The metal titanium, nickel powder coatings for the method of spon¬taneous free impregnation was used. The study of the kinetics of impregnation of plaits of oxide fibers with melts of lead and tin-lead-bismuth-cadmium alloy was performed at 600–700 oC. The metal melt impregnates metal powders well. The rate of impregnation is quite high 1,1–1,8 mm/s. The obtained results allow the use of titanium pastes for the manufacture of composites from oxide materials with lead matrices. Composites were made. Oxide fiberglass made of CRT waste was selected as the reinforcing material. Lead was chosen as the matrix metal. Despite the fact that lead is a harmful material, but its use as a matrix phase for composites from the action of ionizing radiation is indispensable. Keywords: spontaneous free impregnation, composites, lead melts, oxide fibers, wetting, metal coverings.
Use of Spectroscopy and Computer Simulation to the Study of Surfaces Modified by Ionic Implantation
Authors: Nikolaieva D.Yu. , Honcharov V.V. , Ivashin D.Yu. , Zazhigalov V.O.
Published: July 2021

Using X-ray Photoelectron Spectroscopy (XPS) and energy dispersion spectrometry, the phase and elemental compositions of the nanoscale surface layer of implants are studied. The method of determination of the optimal mode of nanoscale modification of the surfaces of metals and alloys by means of the ionic implantation is presented. The problem of processing the curved surfaces with mathematical calculations and a computer simulation is solved. The proposed technique is tested on synthesized implants. The sample hardness was taken as a criterion.
Reducing Unnecessary Imaging in Children With Multicystic Dysplastic Kidney or Solitary Kidney
Authors: Jawa Natasha A. , Rosenblum Norman D. , Radhakrishnan Seetha , Pearl Rachel J. , Levin Leo , Matsuda-Abedini Mina
Published: July 2021

BACKGROUND AND OBJECTIVES

Children with isolated unilateral multicystic dysplastic kidney (MCDK) or congenital solitary kidney (CSK) undergo serial renal ultrasonography with variable frequency until they are transitioned to adult care. A growing body of literature suggests the value of frequent ultrasonography in this population is limited, providing no benefit to overall outcomes. Despite emerging evidence, ultrasound remains overused, resulting in avoidable health care expenditures and unnecessary use of resources. With our initiative, we aimed to improve quality of care by reducing avoidable ultrasounds in these children.

METHODS

This was a single-center, prospective, interrupted time series of children <18 years with ultrasound-confirmed isolated unilateral MCDK or CSK in the outpatient nephrology clinic to evaluate the effect of a decision-making algorithm on the proportion of children receiving an avoidable ultrasound. An algorithm depicting a consensus, evidence-based protocol for managing pediatric MCDK or CSK was refined through content expert feedback and usability testing to standardize frequency of ultrasonography. Ultrasounds were deemed necessary after birth, at 6 months, and at 2, 5, 10, and 15 years. Differences pre- and postintervention were determined by using a U chart and t and F tests for significance.

RESULTS

The algorithm resulted in a 47% reduction (P < .001) in the proportion of avoidable ultrasounds ordered in children with MCDK and CSK. This reduction was sustainable over a 6-month period and would result in at least $46 000 annual savings.

CONCLUSIONS

Introduction of a clinical decision-making algorithm was associated with a reduction in avoidable ultrasound testing. Improving adherence across providers may allow for an even more pronounced reduction.
Early Use of Bronchodilators and Outcomes in Bronchiolitis
Authors: Shanahan Kristen H. , Monuteaux Michael C. , Nagler Joshua , Bachur Richard G.
Published: July 2021

BACKGROUND AND OBJECTIVES

There are no effective interventions to prevent hospital admissions in infants with bronchiolitis. The American Academy of Pediatrics recommends against routine bronchodilator use for bronchiolitis. The objective of this study was to characterize trends in and outcomes associated with the use of bronchodilators for bronchiolitis.

METHODS

This is a multicenter retrospective study of infants <12 months of age with bronchiolitis from 49 children’s hospitals from 2010 to 2018. The primary outcomes were rates of hospital admissions, ICU admissions, emergency department (ED) return visits after initial ED discharge, noninvasive ventilation, and invasive ventilation. Multivariable logistic regression was used to evaluate the rates of outcomes among hospitals with high and low early use of bronchodilators (on day of presentation).

RESULTS

A total of 446 696 ED visits of infants with bronchiolitis were included. Bronchodilator use, hospital admissions, and ED return visits decreased between 2010 and 2018 (all P < .001). ICU admissions and invasive and noninvasive ventilation increased over the study period (all P < .001). Hospital-level early bronchodilator use (hospitals with high versus low use) was not associated with differences in patient-level hospital admissions, ICU admissions, ED return visits, noninvasive ventilation, or invasive ventilation (all P > .05).

CONCLUSIONS

In a large study of infants at children’s hospitals, bronchodilator therapy decreased significantly from 2010 to 2018. Hospital-level early bronchodilator use was not associated with a reduction in any outcomes. This study supports the current American Academy of Pediatrics recommendation to limit routine use of bronchodilators in infants with bronchiolitis.
Terapia endoscópica de presión negativa para cierre de fístula esófago-yeyunal. Reporte de caso
Authors: Velásquez-Cuasquen Braulio Giovanni , Romo-Romero William Oswaldo , Meza-Rodríguez Julián Andrés , Romo-Fajardo María Camila
Published: July 2021

Introducción. Las fístulas esófago-yeyunales postquirúrgicas pueden llegar a ser mortales. En la actualidad, existen varias alternativas de tratamiento. En los últimos años, la terapia endoscópica de presión negativa se ha convertido un método innovador para el manejo de estas fístulas que ofrece grandes ventajas.
Presentación del caso. Hombre de 72 años diagnosticado con adenocarcinoma gástrico de cuerpo y fondo a quien se le realizó gastrectomía total, linfadenectomía D2 y anastomosis en Y de Roux con intención curativa en un hospital de cuarto nivel en Popayán, Colombia. Sin embargo, en el posoperatorio, presentó síndrome de respuesta inflamatoria sistémica (SRIS) y abdomen agudo producto de fístula esófago-yeyunal. Se realizó manejo inicial con laparotomía, dos lavados de cavidad peritoneal y drenaje abdominal. Posteriormente, el paciente desarrolló abdomen congelado, por lo que no fue posible acceder la anastomosis esófago-yeyunal. Se intentó cierre de fístula mediante la inserción de prótesis metálica autoexpandible, pero el procedimiento no fue exitoso. Se inició terapia de rescate mediante sistema de cierre asistido por vacío (VAC) por vía endoscópica. Luego de 5 recambios del sistema VAC, se logró el drenaje completo de la peritonitis, el cierre completo de la cavidad peritoneal y el cierre de la fuga esófago-yeyunal, con una pequeña formación diverticular residual. La condición del paciente mejoró progresivamente, con reinicio de la vía oral a los 20 días. Además, no se reportaron nuevas complicaciones abdominales en el periodo de seguimiento (17 meses).
Conclusión. La terapia endoscópica de VAC es una nueva alternativa segura y efectiva para el tratamiento de fístulas post quirúrgicas complejas producto de anastomosis esófago-yeyunales.
Factores de riesgo cardiometabólico en gestantes con diagnóstico de preeclampsia
Authors: Gómez-Tejeda Jairo Jesús , Tamayo-Velázquez Odalis , Pérez-Abreu Manuel Ramón , Iparraguirre-Tamayo Aida Elizabeth , Batista-Velázquez Cheilan Yuliet
Published: July 2021

Introducción. La preeclampsia es una enfermedad con etiología desconocida; su relación con factores de riesgo cardiometabólico incrementa el riesgo futuro de la gestante: se triplica el riesgo de hipertensión arterial (HTA) y se duplica el de enfermedad coronaria y de muerte cardiovascular.
Objetivo. Determinar los factores de riesgo cardiometabólicos asociados con la ocurrencia de preeclampsia en mujeres cubanas.
Materiales y métodos. Estudio de casos y controles realizado en 50 gestantes con uno o varios factores de riesgo de enfermedad cardiometabólica atendidas entre febrero y marzo de 2020 en los Servicios de Obstetricia y Perinatología del Hospital Universitario Vladimir Ilich Lenin, Holguín, Cuba, distribuidas así: 25 gestantes con diagnóstico de preeclampsia en el grupo casos y 25 gestantes sin diagnóstico de preeclampsia en el grupo control. La magnitud de asociación entre los factores de riesgo y tener mayor riesgo cardiometabólico y mayor probabilidad de desarrollar preeclampsia se estableció mediante la prueba de chi-cuadrado de Mantel-Haenszel, calculándose los OR y considerándose un nivel de significancia de p<0.05.
Resultados: El grupo de edad más frecuente en la muestra fue el de 25-35 años (50%) y el tiempo de gestación más frecuente fue el tercer trimestre (62%). Respecto a la asociación entre los factores de riesgo y un mayor riesgo cardiometabólico y una mayor probabilidad de desarrollar preeclampsia, se observó una asociación estadísticamente significativa con la obesidad (OR:18.8; IC95%:4.2-83.5; p=0.0002) y con la HTA (OR:4.1; IC95%:1-15.5; p=0.03).
Conclusiones. Con base en los resultados obtenidos, las gestantes con preeclampsia tuvieron más factores de riesgo cardiometabólico como obesidad y HTA.
Liquid chromatographic enantioseparation, determination, bioassay and isolation of enantiomers of Ketorolac: A review
Authors: Bhushan Ravi
Published: July 2021

Ketorolac (Ket) is a potent non-narcotic analgesic drug (among the nonsteroidal anti-inflammatory drugs). The physiological activity of Ket resides with (S)-(−)-Ket while the drug is marketed and administered as a racemic mixture. Therefore, it is desirable that the pharmacokinetics is measured and quantified for enantiomers individually and not as a total drug. The present paper is focused on relevant literature on LC enantioseparation of (RS)-Ket along with bioassay, pharmacokinetic and clinical studies within the discipline of analytical chemistry. HPLC and Thin layer chromatography (TLC) methods using both direct and indirect approaches are discussed. The methods provide chirality recognition even in the absence of pure enantiomers. Besides, a brief discussion on resolution by crystallization and enzymatic methods is included. The most interesting aspects include establishment of structure and molecular asymmetry of diastereomeric derivatives using LC-MS, proton nuclear magnetic resonance spectrometry, and by drawing conformations in three dimensional views by using certain software. A brief discussion has also been provided on the recovery of native enantiomers by TLC.
Development and validation of a nine-item short screening test for ICD-11 gaming disorder (GAMES test) and estimation of the prevalence in the general young population
Authors: Higuchi Susumu , Osaki Yoneatsu , Kinjo Aya , Mihara Satoko , Maezono Masaki , Kitayuguchi Takashi , Matsuzaki Takanobu , Nakayama Hideki , Rumpf Hans-Jürgen , Saunders John B.
Published: July 2021

Background and Aims

A definition of gaming disorder (GD) was introduced in ICD-11. The purpose of this study was to develop a short screening test for GD, utilizing a reference GD group. It also sought to estimate the prevalence of GD among individuals, representative of the general young population in Japan.

Methods

Two hundred eighty one men and women selected from the general population, aged between 10 and 29 years, and 44 treatment seekers at our center completed a self-reported questionnaire comprising candidate questions for the screening test. The reference group with ICD-11 GD was established, based on face-to-face interviews with behavioral addiction experts, using a diagnostic interview instrument. The questions in the screening test were selected to best differentiate those who had GD from those who did not, and the cutoff value was determined using the Youden index.

Results

A nine-item screening test (GAMES test) was developed. The sensitivity and specificity of the test were both 98% and the positive predictive value in the study sample was 91%. The GAMES test comprised two factors, showed high internal consistency and was highly reproducible. The estimated prevalence of GD among the general young population was 7.6% (95% confidence interval; 6.6–8.7%) for males and 2.5% (1.9–3.2%) for females, with a combined prevalence of 5.1% (4.5–5.8%).

Discussion and Conclusion

The GAMES test shows high validity and reliability for screening of ICD-11 GD. The estimated prevalence of 5.1% among the general young population was comparable to the pooled estimates of young people globally.
Functionalizable coaxial PLLA/PDLA nanofibers with stereocomplexes at the internal interface
Authors: Neffe Axel T. , Zhang Quanchao , Hommes-Schattmann Paul J. , Wang Weiwei , Xu Xun , Ahmad Bilal S. , Williams Gareth R. , Lendlein Andreas
Published: July 2021

Multifunctionality of electrospun polylactic acid (PLA) nonwovens was generated by the morphological design of nanofibers. Coaxial fibers with a lower number average molar mass MnPLLA core and a higher MnPDLA shell form PDLA–PLLA stereocrystals at the interface, induced by annealing. In tensile tests under physiological conditions, the core–shell fibers with higher crystallinity (22% compared to 11–14%) had lower Young’s moduliE(9 ± 1 MPa) and lower elongation at break εb(26 ± 3%) than PDLA alone (E = 31 ± 9 MPa, εb = 80 ± 5%), which can be attributed to simultaneous crystallization and relaxation effects. Gelatin incorporated in the PDLA phase was presented on the outer surface providing a biointerface putatively favorable for cell adherence. Gelatin incorporation did not influence the crystallization behavior but slightly loweredTg(60 → 54 °C). Employing exclusively polymers established in the clinic, multifunctionality was generated by design.

Graphic abstract
Correlating rheology and printing performance of fiber-reinforced bioinks to assess predictive modelling for biofabrication
Authors: Sonnleitner David , Schrüfer Stefan , Berglund Linn , Schubert Dirk W. , Lang Gregor
Published: July 2021

A crucial property for the evaluation of bioinks, besides biocompatibility, is printability, which is determined by resolution and shape fidelity. Recently, fiber reinforcement was used to overcome rheological limitations and introduce biomimetic structuring. This study provides a systematic approach to evaluate the printability of fiber reinforced hydrogels. Alginate and Pluronic hydrogels were blended with cellulose nanofibers (CeNF) and polycaprolactone (PCL) microfibers. SEM imaging revealed fiber-induced structural changes. Oscillatory rheological experiments showed that the addition of fiber fragments significantly altered the complex viscosity. A customized setup was utilized to determine strut spreading behavior in a real extrusion printing process. Strikingly, the data displayed excellent correlation with viscoelastic model-based predictions. CeNF increased the shape fidelity of both hydrogels, while PCL microfibers increased the viscosity but resulted in a time dependent loss of structural integrity in Pluronic. The results emphasize the need to complement shear-rheological analysis of bioinks by print-related customized analytical tools.

Graphic abstract
Association Between 25(ОН)D Concentration and Atopic Dermatitis and Its Severity Children Aged from 3 to 6 Years: Cross Sectional Study
Authors: Kashinskaya Tatiana S. , Shakhova Natalia V.
Published: July 2021

Background. The association between the vitamin D provision for children and the atopic dermatitis (AD) development and severity is not clearly determined.

Objective. The aim of the study was to compare 25(OH)D serum concentration in children with AD and in healthy peers with association analysis of 25(OH)D with disease severity and allergen sensibilization.

Methods. The study included children aged from 3 to 6 years with AD and their healthy peers. Vitamin D provision was estimated via 25(OH)D serum concentration determined by chemiluminescent microparticle immunoassay. Vitamin D deficiency was established at 25(OH)D concentration 20 ng/ml, insufficiency — 21–29 ng/ml. Sensibilization to airborne (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat epithelium and dandruff) and food (cow's milk and chicken egg proteins) allergens was determined by IgE concentration revealed via immunofluorescence.

Results. The 25(OH)D serum concentration in children with AD (n = 106) was lower than in their healthy peers (n = 40), median (interquartile range) — 26.5 ng/ml (19.0–35.3) and 32.4 ng/ml (27.9–37.5) respectively (p = 0.012). Meanwhile, vitamin D insufficiency/deficiency according to 25(OH)D concentration was revealed in more than half patients (58%) with AD and in every third child (37%) from control group (OR — 3.5, 95% CI — 1.6–7.5). It was also revealed that 25(OH)D concentration was lower in patients with moderate course of AD (in comparison to mild) as well as in children sensibilized to airborne and/or food allergens.

Conclusion. The vitamin D provision in preschool children is associated with AD, its severity and the presence of sensibilization to airborne and/or food allergens.
Improvement of the procedure for bis(2-chloroethyl)sulfide determination in matrices with high sorption activity
Authors:   Research Institute of Hygiene, Occupational Pathology and Human Ecology Federal State Unitary Enterprise, Federal Medical Biological Agency, Shachneva M. D. , Koryagina N. L. ,   Research Institute of Hygiene, Occupational Pathology and Human Ecology Federal State Unitary Enterprise, Federal Medical Biological Agency, Savelieva E. I. ,   Research Institute of Hygiene, Occupational Pathology and Human Ecology Federal State Unitary Enterprise, Federal Medical Biological Agency
Published: July 2021

A rapid, unified, highly sensitive and selective procedure for bis(2-chloroethyl)sulfide (sulfur mustard, SM) determination in matrices with high sorption activity using gas chromatography-tandem mass-spectrometry (GC-MS/MS) was developed. Ceramic tile, concrete, various types of bricks and polymers were studied as objects of the analysis. The parameters for the GC-MS/MS determination of SM were optimized. The efficiency of five solvents (diethyl ether, 2-chloropropane, acetonitrile, hexane, and acetone) for the extraction of SM from the various matrices was studied. 2-chloropropane was the extraction solvent of choice. The developed procedure is based on the extraction of SM from the matrix and the concentration of the extract under the stream of nitrogen to 0.2 mL followed by GC-MS/MS analysis. The LODs for SM in all investigated matrices were 0.7-0.9 ng/g (0.007-0.009 MPC). The long-term stability of SM in various materials was studied. It was shown that in brick, concrete and ceramic samples the residual amount of SM after five months of storage at 4°C was below the LOD of the method, while in polymer samples under the same storage condition the amount of SM has not changed significantly. The developed procedure has been applied to the analysis of samples from the former chemical weapons destruction facility.
Controlling the correctness of retention parameters variations in reversed phase HPLC using recurrent relations
Authors:   St. Petersburg State University, Zenkevich Igor G. , Derouiche Abdennour ,   St. Petersburg State University, Nikitina Darja A. ,   St. Petersburg State University, Kornilova Tatiana A. ,   St. Petersburg State University, Khakulova Anna A. ,   St. Petersburg State University
Published: July 2021

Recurrent approximation of analytes’ net retention times (tR) in reversed phase high performance liquid chromatography (RP HPLC) at different contents of organic constitu­ent in the eluent (C) is recommended as a method of revealing the reversible hydrate for­ma­tion. The criterion of that are the deviations of the dependences tR(С + DС) = atR(С) + b (*) from linearity, where DС is the constant increment of concentration variations; in our case DС = 5%. However, such deviations are rather small and, hence their measuring requires high robustness of the equipment involved. Besides hydrate formation, there are additional reasons for deviations, namely discrepancies between the real and the selected flows of the eluent. Compa­ring tR values obtained for the same analytes using the same chromatogra­phic column at the same conditions, but with different HPLC instruments using the systems methanol – water as the eluent confirms that tR values of one data set are equal only to approx. 76-98% tR values of another data set. Therefore, the eluent flow in the second case exceeds that in the first regime at the same pro­por­tion. The simple method for revealing such flow deviations is proposed. It is based on the recurrent approximation of tR = f(C) data sets for any compounds forming no hydrates in RP HPLC conditions (chlorobenzene was selected). The absence of the influ­en­ce of any distorted factors is confirmed with values of correlation coefficients for re­cur­rent depen­dencies (*) exceeding 0.999.
Capabilities and limitations of tin direct determination using the spectrometry methods with inductively coupled plasma in Azov and Black sea waters
Authors:   Kuban State University, Abakumova D. D. , Temerdashev Z. A. ,   Kuban State University, Abakumov P.G. ,   Kuban State University
Published: July 2021

The current study discussed the capabilities and limitations of tin direct determination in the waters of the Black and Azov Seas using the ICP-MS and ICP-AES methods without the separation and concentration of the analyte. The conditions for the analysis of waters, the influence of dilution and matrix components on the results of the analysis were established. As the salinity of the seawater increased, the slope of the calibration curve decreased, regardless of the detection method used. The leveling of the matrix effect of seawater on the analytical signal of tin was achieved by diluting the sample up to 100 times. A significant decrease in the analytical signal of tin was observed on the samples of seawater characterized by the high salinity. These methods allowed determining tin at the concentrations ranging from 0.33 μg/dm3 (ICP-MS), 0.37 μg/dm3 (ICP-AES) to 5 μg/dm3 in natural (fresh) water or seawater with low salinity level according to the calibration curve of the deionized water. For ICP-MS and ICP-AES determination of tin in seawater with the salinity level above 6‰ and tin concentration of more than 5 μg/dm3, it was required to use the calibration dependence constructed on the model seawater considering the salinity of the object. The studies have shown that the content of tin in the Kuban River is 0.13 μg/dm3. In the Sea of Azov, the concentration of tin in the water, depending on the sampling site, was less than 0.33 μg/dm3 (Taman) and 1.8 μg/dm3 (Temryuk, commercial port). In the Black Sea, the concentration of tin in the seawater samples from Novorossiysk city was higher and ranged from 0.55 μg/dm3 (embankment) to 1.5 μg/dm3 (seaport) and 2.1 μg/dm3 (grain terminal).
Isotope analysis of highly enriched “silicon-28” by high-resolution inductively coupled plasma mass spectrometry using an internal standard
Authors:   G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (IChHPS RAS), Otopkova P. A. , Potapov A. M. ,   G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (IChHPS RAS), Suchkov A. I. ,   G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (IChHPS RAS), Bulanov A. D. ,   G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (IChHPS RAS), Lashkov A. Yu. ,   G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (IChHPS RAS)
Published: July 2021

In order to study the isotopic effects in semiconductor materials, single crystals of high chemical and isotopic purity are required. The reliability of the obtained data on the magnitude and the direction of isotopic shifts depends on the accuracy of determining the concentration of all stable isotopes. In the isotopic analysis of enriched “silicon-28” with a high degree of enrichment (> 99.99%), it is necessary to determine the impurities of 29Si and 30Si isotopes at the level of 10-3 ¸ 10-5 at. %. At this concentration level, these isotopes can be considered as impurities. It is difficult to achieve high measurement accuracy with simultaneous registration of the main and “impurity” isotopes in such a wide range of concentrations. The registration of analytical signals of silicon isotopes must be carried out in the solutions with different matrix concentrations. The use of the solutions with the high concentration of the matrix element requires the introduction of corrections for matrix noise and the drift of the instrument sensitivity during the measurement. It is possible to reduce the influence of the irreversible non-spectral interference and sensitivity drift by using the method of internal standardization. The inconsistency of the literature data on the selection criteria for the internal standard required studying the behavior of the signals of the “candidates for the internal standard” for the ELEMENT 2 single-collector high-resolution inductively coupled plasma mass spectrometer on the matrix element concentration and the nature of the solvent, as well as on the solution nebulizing time. Accounting for the irreversible non-spectral matrix noise and instrumental drift in isotopic analysis of enriched “silicon-28” and initial 28SiF4 by inductively coupled plasma mass spectrometry had allowed us to reduce by 3-5 times the random component and by more than an order of magnitude the systematic component of the measurement error in comparison with the external standard method. This made it possible to carry out, with sufficient accuracy, the operational control of the isotopic composition of enriched “silicon-28”, both in the form of silicon tetrafluoride and polycrystalline silicon obtained from it, using a single serial device in the range of isotopic concentrations 0.0001–99.999%.
Is there a link between non-alcoholic fatty liver disease aspects and pancreatic cancer? Results of a case-matched study
Authors: REZENDE ACHILES QUEIROZ MONTEIRO DE , GESTIC MARTINHO ANTÔNIO , UTRINI MURILLO PIMENTEL , CHAIM FELIPE DAVID MENDONÇA , SAITO HELENA PAES DE ALMEIDA DE , CHAIM ELINTON ADAMI , CALLEJAS-NETO FRANCISCO , CAZZO EVERTON
Published: July 2021

ABSTRACT Background and Aims: An association between non-alcoholic fatty liver disease (NAFLD) and pancreatic ductal adenocarcinoma (PDAC) has been previously suggested. This study aims at investigating this association and at identifying potential links between variables of the NAFLD spectrum and PDAC. Methods: A cross-sectional case-matched analytical and comparative study was carried out to analyze patients undergoing surgical resection of PDAC and compare them to a control group of individuals undergoing cholecystectomy at a public tertiary teaching hospital, matched by sex, age and BMI. Hepatic histopathological examinations were compared between cases and controls. Results: Of 56 individuals, 36 were male (64.3%) and the median age was 61.5 years old (interquartile range: 57.5 - 70). The participants’ median BMI was 24.3 kg/m2 (interquartile range: 22.1-26.2 kg/m2). Microvesicular steatosis (p=0.04), hepatocellular ballooning (p=0.02), fibrosis (p=0.0003) and steatohepatitis (p=0.03) were significantly more frequent in the group of cases. Odds ratios for hepatocellular ballooning (6.2; 95%CI: 1.2-31.8; p=0.03), fibrosis (9.3; 95%CI: 2.5-34.1; p=0.0008) and steatohepatitis (3.9; 95%CI: 1.1-14.3; p=0.04) were statistically significant in relation to the PDAC prevalence. Conclusions: Significant associations were identified between histopathological aspects of NAFLD (microvesicular steatosis, hepatocellular ballooning, fibrosis, and steatohepatitis) and PDAC.
Mortalidade por COVID-19 padronizada por idade nas capitais das diferentes regiões do Brasil
Authors: Silva Gulnar Azevedo e , Jardim Beatriz Cordeiro , Lotufo Paulo Andrade
Published: July 2021

O crescimento acentuado de casos e óbitos por COVID-19 tem levado à grande sobrecarga do sistema de saúde no Brasil, em especial em cidades como Manaus (Amazonas), Rio de Janeiro e São Paulo. A descrição do impacto da pandemia tem se baseado em números absolutos ou taxas de mortalidade brutas, não considerando o padrão de distribuição das faixas etárias nas diferentes regiões do país. Este estudo tem por objetivo comparar as taxas de mortalidade brutas por COVID-19 com as taxas padronizadas por idade nas capitais dos estados brasileiros e no Distrito Federal. As informações sobre óbito foram acessadas no Sistema de Informação de Vigilância da Gripe (SIVEP-Gripe), e os denominadores populacionais foram baseados nas estimativas disponibilizadas pelo Ministério da Saúde. Para o cálculo das taxas padronizadas por idade, utilizou-se a estrutura etária da população do Brasil estimada para 2020. Os resultados mostram que as maiores taxas brutas foram em Manaus (253,6/100 mil) e no Rio de Janeiro (253,2/100 mil). Após padronização por idade, houve aumento expressivo das taxas na Região Norte. A maior taxa ajustada foi vista em Manaus (412,5/100 mil) onde 33% de óbitos por COVID-19 ocorreram entre menores de 60 anos. A mortalidade em Manaus acima de 70 anos foi o dobro se comparada à do Rio de Janeiro e o triplo se comparada à de São Paulo. A utilização de taxas de mortalidade padronizadas por idade elimina vieses interpretativos, expondo, de forma marcante, o peso ainda maior da COVID-19 na Região Norte do país.