bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Performance Evaluation of Chitosan/zinc Oxide Nanocomposite as a Highly Efficient Adsorbent in the Removal of Reactive Red 198 From Water
Authors: Amirmahani Najmeh , Mahdizadeh Hakimeh , Seyedi Neda , Nasiri Alireza , Yazdanpanah Ghazal
Published: September 2021

Disposal of textile industrial effluents causes many environmental problems. The presence of chemical dyes in textile wastewater lead to the primary environmental pollution as well as the production of hazardous secondary compounds that are toxic and carcinogenic. In this study, Chitosan and Chitosan-zinc oxide (ZnO) nanocomposite were prepared and selected as a low-cost adsorbent with high adsorption capacity for removing reactive red 198 (RR 198) dye from contaminated. After preparation, it was characterized using Fourier-transform infrared spectroscopy [FT-IR], X-ray diffraction spectrophotometer [XRD], and scanning electron microscopy [SEM]. The effect of pH, temperature, time, adsorbent amount, and initial dye concentration were investigated in the removal efficiency of reactive red 198 (RR 198) dyes. The results showed that the maximum adsorption capacity (qm) obtained from the Langmuir equation was 172.41 mg/g in adsorbent dose of 0.1 g/L, pH: 4, temperature of 25°C, adsorption time of 40 min. The thermodynamic parameters demonstrated the spontaneous and endothermic nature of the adsorption process. Due to the high efficiency of chitosan/ZnO nanocomposite in removal of RR 198 from water and advantages such as high adsorption capacity, simple synthesis, and easy application, it can be used as an effective method in removal of RR 198 from water.
Identification of miR-338-5p and miR-4776-3p as mediators of articular cartilage degeneration
Authors: Wang Jiaxu , Guan Xin , Zhang Lele , Shao Shuilin , Gao Bo , Li Haixia , Huo Litao , Huang Shibo , Wu Jigong , Cui Xiang
Published: September 2021

Purpose

Osteoarthritis is one of the most common chronic diseases nowadays, and can cause serious physical illness and economic burden. Cartilage degeneration is one of primary reasons for osteoarthritis, but there were not thorough studies on cartilage lesions.
Methods

miR-338-5p and miR-4776-3p were overexpressed and knocked down in SW1353 cells. Dual luciferase assay is used to detect the binding of miR-338-5p, miR-4776-3p and SOX6. The expression of MMP13, TNFA, IL6, MCP1, PARP, Runx2, ALP, OPN, WNT4, WNT16, TRACP and CTSK was quantified by qPCR. And the expression of WNT4 at the protein level was quantified by WB.
Results

In this study, we found miR-338-5p and miR-4776-3p showed significantly high expression on cartilage in osteoarthritis through bioinformatics methods, and verified miR-338-5p and miR-4776-3p can improve catabolism, and trigger biological processes such as inflammation and apoptosis. Meanwhile we validated miR-338-5p and miR-4776-3p may play negative regulation in the process of bone biology.
Conclusions

Our study showed that miR-338-5p and miR-4776-3p can be regarded as medium of articular cartilage degeneration, and it provided new biomarker of early diagnosis in cartilage disease and osteoarthritis.
Identification and Validation of a Glycolysis Related Metabolic Reprogramming Gene Signature for Predicting Survival in Colon Cancer Patients
Authors: Liu Gang , WU Xiaowang , Chen Jian
Published: September 2021

Background

Colon cancer (CC) is one of the most common gastrointestinal malignant tumors with high mortality rate. Because of malignancy and easily metastasis feather, and limited treatments, the prognosis of CC remains poor. Glycolysis is a metabolic process of glucose in anoxic environments which is an important way to provide energy for tumor. The role of glycolysis in CC largely remains unknown and is necessary to be explored.
Method

In our study, we analyzed glycolysis related genes expression in CC, patients gene expression and corresponding clinical data were downloaded from GEO dataset, glycolysis related genes sets were collected from Msigdb. Through COX regression analysis, prognosis model based on glycolysis-related genes was established. The efficacy of gene model was tested by Survival analysis, ROC analysis and PCA analysis. Furthermore, the relationship between risk scores and clinical characteristic was researched.
Results

Our findings identified 13 glycolysis related genes (NUP107, SEC13, ALDH7A1, ALG1, CHPF, FAM162A, FBP2, GALK1, IDH1, TGFA, VLDLR, XYLT2 and OGDHL) consisted prognostic prediction model with relative high accuracy. The relationship between prediction model and clinical feathers were specifically studied, results showed age > 65years, TNM III-IV, T3-4, N1-3, M1 and high-risk score were independent prognostic risk factors with poorer prognosis. Finally, model genes were significantly expressed and EMT were activated in CC patients.
Conclusion

This study provided a new aspect to advance our understanding in the potential mechanism of glycolysis in CC.
Burnout Among Saudi Radiological Sciences Undergraduate Students: A Cross-Sectional Study
Authors: Alshamrani Khalid , Alkenawi Abdulkader , Merdah Abdulaziz , Munshi Wael , Alattas Ahmed , Althaqafy Majid , Qurashi Abdulaziz , Kaifi Reham
Published: September 2021

Background

Burnout syndrome may adversely affect health care workers and health sciences students. The purpose of this study was to assess the prevalence of burnout among Saudi third- and fourth-year radiological sciences students across three campuses of King Saud bin Abdulaziz University for Health Sciences.
Methods

An exploratory, cross-sectional study was conducted among 176 Saudi radiological sciences students, using the Maslach Burnout Inventory-General Survey for Students. The 16-item questionnaire was administered electronically. The arithmetic means of individual items making up each scale of burnout were calculated, and statistical analyses were performed using Mann-Whitney U nonparametric test.
Results

From the 176 radiological sciences students approached, 96 (54.5%) completed the questionnaire. The percentage of students who were at moderate to high risk of burnout for emotional exhaustion, cynicism, and professional efficacy were 70.8%, 75% and 74%, respectively. Fourth-year students emotional exhaustion mean scale score was 19.3 ± 6.8 indicating significant higher burnout levels (P = 0.042), compared to third-year students mean scale score of 15.9 ± 7.2. Fourth-year female students cynicism mean scale score was 16.3 ± 7.6 indicating significant higher burnout levels (P = 0.035), compared to third-year female students mean scale score of 10.3 ± 7.1. Fourth-year female students showed significant lower professional efficacy mean score (21.1 ± 8.0), compared to males (26.1 ± 7.9, P = 0.007).
Conclusions

Our study shows 73.3% moderate to high burnout rates among Saudi radiological sciences students. A greater proportion of fourth year female students reported high levels of emotional exhaustion. Burnout increases as students advance to the fourth year. A block/modular curriculum structure for fourth-year courses may be necessary to reduce burnout among fourth-year students. The provision of academic counseling can relieve students' emotional stress and therefore reduce the risk of burnout.
L attice V ibrational C haracteristics , Crystal Structure s , and D ielectric P roperties of Li Mn PO 4 Microwave Dielectric Ceramics as a Function of Sintering Temperature
Authors: wang xiangyu , xiao encai , Zhang Lingcui , Xu Yue , liu tong , Yi Junzhi , Song Kaixin , Qi Ze-ming , shi feng
Published: September 2021

LiMnPO4 (LMP) microwave dielectric ceramics were manufactured at different temperatures via a standard solid-state reaction method, and the LMP ceramic sintered at 750 °C displayed dielectric properties of εr = 7.82, Q × f = 29,189 (f = 12.7 GHz). The lattice vibrational characteristics of LMP ceramics were studied utilizing both infrared reflection and Raman scattering spectroscopy to clarify the basic principle of the dielectric response. The intrinsic properties that were fitted and simulated based on the infrared spectra agreed with the measured property values. The low-frequency vibrational modes contributed more to the dielectric properties than the high-frequency modes. Upon increasing the temperature, the permittivity was positively correlated with the bond length but showed the opposite trend of the Raman shift of mode 9 Ag(υ1). The Q × f value was positively correlated with the packing fraction but negatively correlated with the FWHM of mode 10 Ag(υ3). Thus, the structure-property relationships of LMP ceramics were established as a function of sintering temperature.
­ Characterization of the Immune Infiltration Landscape and Identification of Prognostic Biomarkers for Esophageal Cancer
Authors: Chen Yuanmei , Huang Xinyi , Peng Haiyan , Weng Guibin , Huang Zhengrong , Zhang Yangfan , Xiao Tianya , Chen Junqiang , Zhu Kunshou , Xu Yuanji
Published: September 2021

Background. Esophageal cancer (EC) is the 7th most common neoplasm and the 6th most common cause of cancer-related death worldwide. Immunotherapy is an effective treatment for EC patients. However, there are no dependable markers for predicting prognosis and immunotherapy responses in EC. Our study aims to explore prognostic models and markers in EC as well as predictors for immunotherapy. Methods. The expression profiles of EC were obtained from The Cancer Genome Atlas (TCGA), the Gene Expression Omnibus (GEO), and International Cancer Genome Consortium (ICGC) databases. Cox regression analysis was performed to construct a prognostic model. Overall survival and receiver operating characteristic curve analyses were applied to verify the accuracy of the model. The CIBERSORT algorithm was conducted to quantify the infiltration of different immune cells, and EC was grouped into three immune cell infiltration (ICI) clusters. PD-1 and PD-L1 expressions were compared between the ICI clusters. Overall survival analysis between ICI score and tumor mutation burden was conducted. The immunotherapy response of patients in different ICI score clusters was also compared. The copy number variations, somatic mutations, and single nucleotide polymorphisms were analyzed. Enrichment analyses were also performed. Results. A prognostic model was successfully constructed. Three ICI clusters were identified, and the clusters with high immune and stromal scores tended to have more immune-activated phenotypes and higher expressions of PD-1 and PDL1. The ICI score may be used as a predictor independent of tumor mutation burden. Patients with higher ICI score tended to have better immunotherapeutic responses than those with lower scores. Enrichment analyses showed that the differentially expressed genes were mostly enriched in microvillus and the KRAS and IL6/JAK/STAT3 pathways. The top eight genes with the highest mutation frequencies in EC were identified and all related to the prognosis of EC patients. Conclusions. Our study established an effective prognostic model and identified markers for predicting the prognosis and immunotherapy response of EC patients.
Numerical Analysis of Fairings for Bicycles
Authors: Bhavani Polamarasetty Teja , Bhavani P. Teja , Rao Y. Seetharama , Murthy B. V. Ramana
Published: September 2021

Aerodynamics is the study of moving air's properties and the interactions between moving air and solids. Rider gets slammed into air particles while riding that gets compressed once rider hit them and then become spaced out once they flow over the rider. The distinction in atmospheric pressure from your front to your back creates a retardant force. The force that's perpendicular to the oncoming flow direction is the lift force. It contrasts with the drag force. Aerodynamic shapes reduce this pressure drag and lift by minimizing that difference in pressure and allowing the air to flow more smoothly over your front, reducing the low-pressure wake behind the cyclist and reducing this drag, and increasing speed in this paper; fairings designed. NACA airfoil as a base, fairings are designed using CATIA.CFD analysis is carried out on the bicycle with a fairing to calculate drag and lift force. As the position of cyclists isn't modified and due to fairing, the air resistance reduces, which may increase the comfort level of cyclists. From this analysis, the economical fairing can be determined, facilitating additional drag and producing less lift.
Analysis of the Results of Gastrin-17 and its Related Influencing Factors in Health Check-Up Population
Authors: Shen Yan , Zeng Junchao , Xu Sanping , Yang Rui
Published: September 2021

Background: To analyze the difference of serum gastrin-17 levels in different sexs, ages, and body mass index (BMI) of healthy people, and to explore the correlation between gastrin 17 and pepsinogen, in addition to study the influence of Helicobacter pylori infection and various inflammatory factors on the secretion level of gastrin-17. Methods: 531 subjects who received physical examination in our center from April 2019 to December 2019 were enrolled in the study. All the staff were tested for gastrin 17 (G17), pepsinogen I (PGI), pepsinogen II (PGII), PGI / PGII (PGR), Helicobacter pylori (Hp) and C-reactive protein (CRP) and other inflammatory factors. To compare the difference of G17 secretion in different populations and its correlation with PG, then to understand the HP infection and the influence of inflammatory indicators on G17. Results: There was no significant difference in the secretion level of G17 in different sex, age and BMI (P > 0.05); G17 was positively correlated with PGI and PGII, but negatively correlated with PGR; the level of G17 in Helicobacter pylori positive patients was 10.16±12.84, which was significantly higher than that in negative patients(3.27±6.65), P =0.017, 95% CI: 1.713 (1.100, 2.668); the increase of serum amyloid A(SAA) in different inflammatory indicators was the high-risk factor of G17 abnormality, P=0.016, 95% CI: 2.692 (1.202, 6.028), obviously CRP and erythrocyte sedimentation rate (ESR) had no effect on G17 abnormalities. Conclusions: The secretion of G17 is closely related to PG and HP. Combined screening is helpful for early screening of gastrointestinal diseases in healthy or high-risk groups of gastric cancer, but the influence of inflammatory indicators on G17 should be excluded to improve the reliability of the results.
Estimation of Runoff, Baseflow and ground water status in Parasai-Sindh watershed of SAT region, India
Authors: Kumari Reena , Sharma Babloo , Kumari Pratibha
Published: September 2021

A study of runoff and baseflow estimation and its impact ground water status are typically limited in semi-arid region of India. We are focused on runoff and baseflow in the Parasai-Sindh watershed, with the aim of analyzing the influence of watershed management on the response characteristics of discharge. The geological area watershed is 12.46 km2 and its main stream is found to be of 4th order. The runoff and baseflow of watershed were estimated by subtracting barometric pressure from the stage recoded by Baro and Diver install at outlet to get actual stage of runoff passing over it. The results indicate that out of 49.2 mm rainfall event, runoff and baseflow at outlet of watershed were found as 20.98% and 4.19%, respectively. Whereas, runoff and baseflow were recorded 14.12% and 11.18%, respectively against 86.2 mm rainfall. Total runoff and baseflow produced from outlet was recorded as 16 and 7%, respectively.
Association of Sequence types, Antimicrobial Resistance and Virulence Genes in India isolates of Klebsiella pneumoniae: A Comparative Genomics Study
Authors: Sundaresan Abhirami Krishnamoorthy , Vincent Keerthana , Mohan Ganesh Babu Malli , Ramakrishnan Jayapradha
Published: September 2021

Klebsiella pneumoniae is an important ESKAPE pathogen that causes sepsis, urinary tract infections, peritonitis, intraabdominal abscesses and upper respiratory infections. The strains exhibiting multidrug resistance and hypervirulence are priority pathogens for which immediate treatment and dissemination prevention strategies are required. The hypervirulent drug resistant K. pneumoniae is associated with high mortality rates. Numbers of environmental strains also have acquired virulence genes. Hence to gain a better understanding of the spread of antimicrobial resistant genes across the country over 10 years and to delineate environmental and clinical K. pneumoniae, a comparative genomics investigation was made. This is the first comparative genomic study using India isolates of K. pneumoniae, which includes publicly available WGS of 144 clinical and 9 environmental strains collected during 2010–2020. The blaCTX-M-15 was widely distributed in clinical isolates since 2013 and increased over time from 5 % to 30 %. The co-existence of blaNDM and blaOXA was observed in 22 % of clinical strains. Diverse serotypes were found among the 153 K. pneumoniae isolates, of which, K51 (28%) and K64 (21.56%) were majorly found. Most of the K51 isolates belong to ST231 (93.02 %). And more than 50% of KL51 strains were found to have both rmpA and magA. The number of associated virulence genes (rmpA, magA, entB, ybtS, iutA, alls,) appeared to be higher in ST231-KL51 and ST23-KL1 isolates. Of greatest concern, these virulence genes are observed in environmental strains aswell. More than 97% of clinical strains have yersinibactin (ybtS), aerobactin (iutA) genes. Importantly, 98% of ESBL and 62% of carbapenamasen isolates harboured ybtS, iutA and rmpA, magA respectively. The IncF conjugative plasmids are predominant in K. pneumoniae, which contribute to the spread of AMR, and virulence genes. The increasing trend in hypervirulent strains was observed from 2017. The phylogenetic analysis separates the environmental from clinical strains and is characterized by uncommon STs and serotypes. Thus, the study illustrates the K. pneumoniae genomic surveillance in India representing the phylogenetic evolution, STs, AMR, virulence, serotype to provide more attention for immediate treatment and preventing the dissemination of K. pneumoniae.
Fragility syndrome: determinant factors in institutionalized elderly
Authors: Silva Daniela Fonseca , Alves Roberta Almeida , Pesavento Thomas Fernando Coelho , Vilarinho Manoela , Lombardi Junior Império , Agner Vania Fernanda Clemente
Published: September 2021

The aim of the study was to evaluate the frailty syndrome in residents of a Long-Term Care Facility for the Elderly. A cross-sectional study was carried out on 24 subjects over the age of 60 years. For the screening of frailty syndrome, the criteria of the Cardiovascular Study were used, which classifies the subjects into fragile, pre-fragile and non-fragile according to five criteria: decreased handgrip strength; self-reported fatigue; decrease in walking speed; unintentional weight loss; and low level of physical activity. The average age of the population studied was 81.13 years, with 54.20% being female. Among the elderly, 83.33% were frail, 12.50% were pre-frail and 4.17% were not frail. Elderly people over 80 years old had a higher incidence of frailty when compared to those aged 60 - 79 years, with 85.7% and 80%, respectively. Since 66.67% of the elderly had decreased handgrip muscle strength, 37.50% reported fatigue, 41.67% demonstrated decreased gait speed, 12.50% unintentional weight loss and 87.50% were physically inactive. We identified a high prevalence of DES among the elderly residing in the institution studied, thus reinforcing the importance of early screening for frailty in institutionalized elderly.
Avaliação da padronização das sondas periodontais do tipo Williams e OMS de diferentes marcas
Authors: Tonus Cristiane , Sobral Natália , Ferla Douglas , Galafassi Daniel , Butze Juliane Pereira
Published: September 2021

Objetivos: O estabelecimento do diagnóstico clínico periodontal tem como base a avaliação de parâmetros clínicos por meio da sondagem periodontal, sendo através desses resultados que o Cirurgião Dentista fará a melhor escolha de tratamento. Porém, possíveis erros encontrados na padronização das sondas periodontais podem levar a um plano de tratamento inadequado e/ou ineficiente. O presente estudo teve como objetivo avaliar a padronização de seis sondas periodontais do tipo Williams e seis sondas do tipo OMS de diferentes marcas comerciais. Materiais e Métodos: Com o auxílio de um paquímetro digital e de uma balança digital de alta precisão, foi avaliado o peso da sonda, o diâmetro do cabo, o diâmetro da ponta ativa/esfera, e distância das marcações. Além disso, foi feito uma comparação dos preços de cada sonda, para que fosse possível se avaliar o custo/benefício de cada sonda periodontal. Resultados: Os resultados demonstraram que as sondas das seis marcas comerciais avaliadas, tanto das sondas do tipo OMS quanto do tipo Williams apresentaram algum tipo de distorção em relação às medidas consideradas ideais pela OMS (Organização Mundial da Saúde). Conclusão: As sondas da marca Hu-Friedy, tanto do tipo OMS quanto Williams, apresentaram melhores marcações milimetradas entre todas as marcas avaliadas.
Prevalência de lesões bucais em tecidos mole e duro diagnosticadas em idosos em um serviço histopatológico de referência
Authors: Silva Annelise Lopes Cunha e , Nobre Cabral Lioney
Published: September 2021

O envelhecimento populacional é um fenômeno mundial, sendo percebido também no estado do Amazonas. Com a alta expectativa de vida, o enfoque na saúde geral e bucal impactam diretamente a qualidade de vida da pessoa. Desta forma, os levantamentos acerca da população geriátrica não devem ser restritos às alterações fisiológicas da idade, devendo abordar também as manifestações patológicas, retratando assim quais são as lesões bucais mais recorrentes. O trabalho em questão visa levantar o número de lesões bucais prevalentes em tecido mole e duro em idosos. Sendo feito a partir de um levantamento das lesões bucais prevalentes em tecido mole e duro que acometeram os idosos registrados nos laudos do Serviço de Patologia Oral e Maxilofacial da Universidade do Estado do Amazonas, SEPAT-UEA, entre os anos de 2012 a 2018. Segundo os dados coletados, a categoria de neoplasias de tecido mole (28,94%) teve o maior número de casos, em que a lesão mais prevalente, sendo esta do mesmo grupo, foi a hiperplasia fibrosa inflamatória (14,04%). Teve maior acometimento em mulheres (54,91%), pessoas com 60-69 anos (74,77%), usuários de próteses removíveis (15,56%) e a mandíbula (17,28%) foi a localização mais comum. Com as informações adquiridas, a partir de um serviço de referência do estado do Amazonas, é possível ter um melhor direcionamento dos recursos para a população geriátrica tendo um maior enfoque para as lesões mais prevalentes visando assim uma melhor saúde bucal e consequentemente uma melhor qualidade de vida.
Reabilitação protética-periodontal: relato de caso
Authors: Palaoro Júlia , Borges Simon Amado , Bellan Mariá Cortina , Butze Juliane Pereira
Published: September 2021

Introdução: Atualmente, procedimentos odontológicos vêm enaltecendo resultados pela excelência estética, funcional e biológica. Visto que áreas estéticas representam um desafio ao Cirurgião-Dentista, para que um sorriso harmônico seja construído, é necessário um equilíbrio entre a estética “branca” e “vermelha”. Objetivos: O objetivo do presente estudo foi, por meio de um relato de caso, descrever um tratamento que restabeleceu a harmonia do sorriso através de uma cirurgia periodontal para posterior reabilitação protética. Materiais e Métodos: Através da análise de prontuários de pacientes atendidos na clínica do Complexo Odontológico do Centro Universitário da Serra Gaúcha – FSG entre os anos de 2018 e 2019, selecionou-se um prontuário de um paciente que realizou reabilitação protética com tratamento cirúrgico-periodontal prévio. Resultados: Foi constado através de fotografias que comparam o sorriso pré e pós reabilitação, que a harmonia dos tecidos dentários e gengivais e as expectativas do tratamento proposto foram atingidas determinando metas estéticas, funcionais e biológicas através de um correto diagnóstico e planejamento. Conclusão: No presente relato, a integração dos tratamentos cirúrgico-periodontal e reabilitador trouxe resultados satisfatórios quanto à estética e função, devolvendo autoestima à paciente. O tratamento multidisciplinar possibilitou melhorar a relação entre a estética branca e vermelha, promovendo um excelente resultado dentro das limitações do caso.
Avaliação in vitro da atividade fotoprotetora do extrato hexânico de Psidium araçá (Psidium guineense sw.)
Authors: Morais Sheyliane Rego , Santana Maria Tays Pereira , Gomes Lucas Linhares , Santos Thallita Alves dos , Teles Yanna Carolina Ferreira , Oliveira Heloisa Mara Batista Fernandes de , Sousa Aleson Pereira de , Oliveira Filho Abrahão Alves de
Published: September 2021

A radiação ultravioleta (UV) é um potente carcinógeno, principalmente a UV-B, capaz de provocar danos ao DNA, relacionado a formação de radiação livres. A excessiva exposição solar e sem prevenção contra os raios UV representa um grande risco para o desenvolvimento de patologias com malignidade, dentre elas o câncer de pele. O emprego de extratos vegetais brasileiros com potencial fotoprotetor é sem dúvida um caminho inovador. O araçá ou araçá-do-campo por exemplo, da família Myrtaceae, espécie Psidium guineense Sw., possui grande potencial para exploração econômica e tem boa aceitação in natura, Dessa forma, o presente estudo tem por objetivo avaliar a atividade fotoprotetora do extrato hexânico do Psidium guineense Sw. Foram realizadas varreduras de 290 a 320nm (com intervalos de 5nm) em concentrações de 50, 100, 500 e 1000μg/mL em amostras de 2,0 mL. Os dados foram aplicados à equação de Mansur para aferir o FPS in vitro. Os resultados dessa pesquisa demonstraram que o extrato hexânico de Psidium guineense Sw. apresenta significativa atividade fotoprotetora nas concentrações de 500 e 1000 μg/mL mostrando-se superior ao FPS necessário. Assim, os resultados sugerem que possa ser utilizado como alternativa fitocosmética, tornando-se uma opção mais acessível.
Enseignement et évaluation des mathématiques à distance durant la Covid-19
Authors: Tremblay Melanie , Delobbe Anne-Michèle
Published: September 2021

La pandémie liée au coronavirus SARS-CoV-2 a entraîné une multitude de mesures visant à contrer sa propagation. Parmi elles, la fermeture des établissements scolaires et le passage non-planifié à l’enseignement à distance. Le présent texte porte son attention sur l’expression de la dynamique d’enseignement-apprentissage-évaluation (mai-juin 2020) en mathématique auprès de 311 enseignants primaire et secondaire. Les résultats dégagent cinq principaux enjeux identifiés par les répondants. L’activité mathématique menée sous la modalité synchrone est davantage discuté et on y constate la place importante prise par l’exposé magistral et la résolution de problèmes issus de manuels. Les objets retenus par les enseignants dans l’exercice du jugement en évaluation surprennent et semblent teintés par différentes décisions ministérielles.
Simulation of railway marshalling yards using the methods of the queueing theory
Authors: Zharkov M. L. , Pavidis M. M.
Published: September 2021

Aim. The paper primarily aims to simulate the operation of railway transportation systems using the queueing theory with the case study of marshalling yards. The goals also include the development of the methods and tools of mathematical simulation and queueing theory. Methods. One of the pressing matters of modern science is the development of methods of mathematical simulation of transportation systems for the purpose of analyzing the efficiency, stability and dependability of their operation while taking into account random factors. Research has shown that the use of the most mature class of such models, the singlephase Markovian queueing systems, does not enable an adequate description of transportation facilities and systems, particularly in railway transportation. For that reason, this paper suggests more complex mathematical models in the form of queueing networks, i.e., multiple interconnected queueing systems, where arrivals are serviced. The graph of a queueing network does not have to be connected and circuit-free (a tree), which allows simulating transportation systems with random structures that are specified in table form as a so-called “routing matrix”. We suggest using the BMAP model for the purpose of describing incoming traffic flows. The Branch Markovian Arrival Process is a Poisson process with batch arrivals. It allows combining several different arrivals into a single structure, which, in turn, significantly increases the simulation adequacy. The complex structure of the designed model does not allow studying it analytically. Therefore, based on the mathematical description, a simulation model was developed and implemented in the form of software. Results. The developed models and algorithms were evaluated using the case study of the largest Russian marshalling yard. A computational experiment was performed and produced substantial recommendations. Another important result of the research is that significant progress was made in the development of a single method of mathematical and computer simulation of transportation hubs based on the queueing theory. That is the strategic goal of the conducted research that aims to improve the accuracy and adequacy of simulation compared to the known methods, as well as should allow extending the capabilities and applicability of the model-based approach. Conclusions. The proposed model-based approach proved to be a rather efficient tool that allows studying the operation of railway marshalling yards under various parameters of arrivals and different capacity of the yards. It is unlikely to completely replace the conventional methods of researching the operation of railway stations based on detailed descriptions. However, the study shows that it is quite usable as a primary analysis tool that does not require significant efforts and detailed statistics.
Risk Model of German Corona Warning App – Reloaded
Authors: Braband J. , Shäbe H.
Published: September 2021

Aim. In this paper we discuss the risk model of the German Corona Warning App in two versions. Both are based on a general semi-quantitative risk approach that is not state of the art anymore and for some application domains even deprecated. The main problem is that parameter estimates are often only ordinal scale or rank numbers for which such operations as multiplication or division are not clearly specified. Therefore, it may results in underestimation or overestimation of the associated risk. Methods. The risk models that are used in the apps are analyzed. Comparison of the nomenclature of model parameters, their influence on the result, approaches to the generation of a combined risk assessment is carried out. The effectiveness of the models is analyzed. Results. It is shown that most of the parameters in the model are used only as binary indicator variable. It has been found that the Corona Warning App uses a much more limited model that does not even assess risk, but relies on one parameter which is weighted exposure time. It has been shown that the application underestimates this parameter and therefore may erroneously reassure users. Thus, it may be concluded that the basic risk model implemented before version 1.7.1., is rather a dosimetric model that depends on the calculated virus concentration and does not depend on exposure and other parameters (excluding some threshold values). It is not even a risk model as defined by many standards. Changes of the risk model in the later version are not fundamental. In particular the later model also assesses not individual risk, but individual exposure according to the results. In addition, the model greatly underestimates the duration of exposure. Although it is reported that about 60% of the app’s users have shared positive test results, the absolute number of published results is less than 10% of all positive test results. Therefore, from an individual point of view, the application is effective only in 10% of cases, or even less. Conclusions. As the Corona Warning App also has other systematic limitations and shortcomings it is advised not to rely on its results but rather on Covid testing or vaccination. In addition, if there are enough virus tests available in the near future, the application will even become outdated. It will be better to develop an application that can assess risks a priori, as a kind of decision support for its users based on their individual risk profile.
Chemogenomic Approaches for Revealing Drug Target Interactions in
Drug Discovery
Authors: Bhargava Harshita , Sharma Amita , Suravajhala Prashanth
Published: September 2021

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The drug discovery process has been a crucial and cost-intensive process. This cost is not only monetary but also involves risks, time, and labour that are incurred while introducing a drug in the market. In order to reduce this cost and the risks associated with the drugs that may result in severe side effects, the in silico methods have gained popularity in recent years. These methods have had a significant impact on not only drug discovery but also the related areas such as drug repositioning, drug-target interaction prediction, drug side effect prediction, personalised medicine, etc. Amongst these research areas predicting interactions between drugs and targets forms the basis for drug discovery. The availability of big data in the form of bioinformatics, genetic databases, along with computational methods, have further supported data-driven decision-making. The results obtained through these methods may be further validated using in vitro or in vivo experiments. This validation step can further justify the predictions resulting from in silico approaches, further increasing the accuracy of the overall result in subsequent stages. A variety of approaches are used in predicting drug-target interactions, including ligand-based, molecular docking based and chemogenomic-based approaches. This paper discusses the chemogenomic methods, considering drug target interaction as a classification problem on whether or not an interaction between a particular drug and target would serve as a basis for understanding drug discovery/drug repositioning. We present the advantages and disadvantages associated with their application.
Recent Studies on Neglected Drug Design
Authors: de Sousa Natália Ferreira , Scotti Luciana , Rodrigues Gabriela Cristina Soares , de Moura Érika Paiva , Costa Barros Renata Priscila Barros , Sessions Zoe L. , Muratov Eugene N. , Scotti Marcus Tullius
Published: September 2021

Background:

Neglected diseases require special attention when looking for new therapeutic alternatives, as these are diseases of extreme complexity and severity that affect populations belonging to lower social classes who are lacking access to basic rights such as basic sanitation.

Introduction:

Among the alternatives available for obtaining new drugs is Medicinal Chemistry, which is responsible for the discovery, identification, invention and preparation of prototypes. In this perspective, the present work aims to make a bibliographic review on the recent studies of Medicinal Chemistry applied to neglected diseases.

Method:

A literature review was carried out by searching the “Web of Sciences” database, including recent articles published in the Neglected Drug Design.

Results:

In general, it was noticed that the most studied neglected diseases corresponded to Chagas disease and leishmaniasis, with studies on organic synthesis, optimization of structures and molecular hybrids being the most used strategies. It is also worth mentioning the growing number of computationally developed studies, providing speed and optimization of costs in the procurement process.

Conclusion:

The CADD approach and organic synthesis studies, when applied in the area of Medicinal Chemistry proved to be important in the research and discovery of drugs for Neglected Diseases, since the planning of the experimental methodology used to obtain it, as well as in the selection of compounds with greater activity potential.
Ivabradine for Uncontrolled Sinus Tachycardia in Thyrotoxic Cardiomyopathy – Case Report
Authors: Frenkel Amit , Bichovsky Yoav , Arotsker Natan , Besser Limor , Joshua Ben-Zion , Fraenkel Merav , Zahger Doron , Klein Moti
Published: September 2021

Background:

Beta blockers, mainly propranalol, are usually administered to control heart rate in patients with thyrotoxicosis, especially when congestive heart failure presents. However, when thyrotoxicosis is not controlled, heart rate may be difficult to control even with maximal doses of propranolol. This presentation alerts physicians to the possibility of using ivabradine, a selective inhibitor of the sinoatrial pacemaker, for the control of heart rate.

Case presentation:

We present a 37-year-old woman with thyrotoxicosis and congestive heart failure whose heart rate was not controlled with a maximal dose of beta blockers during a thyroid storm. The addition of ivabradine, a selective inhibitor of the sinoatrial pacemaker, controlled her heart rate within 48 hours.

Conclusion:

Ivabradine should be considered in patients with thyrotoxicosis, including those with heart failure, in whom beta blockers are insufficient to control heart rate
Role of Major Histocompatibility Complex Genes in the Susceptibility and Protection of Primary Open Angle Glaucoma and Primary Congenital Glaucoma
Authors: Gil-Carrasco Félix , Alvarez-Padilla Marla , Hernández-Doño Susana , Ponce-Coria José , García-Silva Rafael , Granados Julio
Published: September 2021

Introduction:

Glaucoma is a prevalent disease seen in the Ophthalmology department that includes a group of neurodegenerative eye pathologies associated with total loss of vision. It is known for its clinical diversity and secondary to this, it is assumed that multiple genes play a role in its pathogenesis. Among these, those that regulate the immune response which includes the HLA genes are of particular interest because they have been associated with a subgroup of glaucoma patients known as Primary Open Glaucoma.

Methods:

In this study, we studied 3 different groups of patients with glaucoma in whom HLA alleles were determined by sequence-specific primers (SSP) technique.

Results:

An association of HLA-DRB1*16 was found with the susceptibility to develop Primary Congenital Glaucoma. In addition, HLA-DRB1*14 was associated with glaucoma without angular dysgenesis, and HLA-DRB1*03 to glaucoma with iridocorneal dysgenesis.

Conclusion:

In conclusion, the data obtained allow us to suggest that glaucoma is a clinical and genetically heterogeneous disease in which one of the subgroups has an autoimmune mechanism in which the Mexican mestizo population shows genetic susceptibility and it differs from POAG with angular dysgenesis and POAG without dysgenesis.
Photocatalytic Properties of TiO2 for the Degradation of O3: Examined by Environmental Parameters
Authors: Skov Magnus Christoffer , Kristensen Steffen Enggaard , Mikkelsen Teis Nørgaard
Published: September 2021

Background:

This paper describes how environmentally relevant parameters affect titanium
dioxide's photocatalytic properties (TiO2) to decompose ozone (O3).

Methods:

Thus, experiments have been carried out in a box chamber with TiO2 coated roofing membrane
samples to determine the significance of light intensity, temperature, initial O3 concentration,
and relative humidity. Furthermore, an outdoor experiment was conducted where the roofing membrane
was subjected to natural sunlight.

Results:

The results show a significant photocatalytic effect of TiO2. The half-life of the O3 decay
curve is 5.8 min in near-ambient UV-light exposure compared with 7.1 min in dark conditions. Experiments
conducted at higher light intensity show a more extensive degradation of O3, where the value
of the reactive uptake coefficient increases from 0.044 to 0.051. Also, the measurements carried out
under natural sunlight show a photocatalytic effect where the uptake coefficient value is 0.046. A
larger photocatalytic effect is detected for the experiments conducted at 283 K and 303 K temperatures
compared with experiments under standard conditions.

Conclusion:

Experiments carried out with a very high initial concentration of O3 show that 28.1 μg of
O3 is decomposed in ambient conditions, where 2.3 μg is destroyed. This demonstrates that light intensity,
temperature, ozone concentration, and relative humidity significantly impact TiO2's degradation
of O3.
Physicochemical characterization of licuri oil and ucuuba butter
Authors:   University of Campinas, Campinas, Brazil, Silva Thais Jordânia , Grimaldi Larissa , Lüdtke Fernanda Luisa , Rodrigues de Godoi Kamila Ramponi , Silva Mayanny Gomes , Grimaldi Renato , Ribeiro Ana Paula Badan
Published: September 2021

The Brazilian rainforest is a rich source of exotic fats. The physical and chemical properties of such fats are not well-known. This article looks at the physicochemical characterization of two fats from the Brazilian Amazon Rainforest: licuri oil and ucuuba butter.
Nefarious to noteworthy: Lipid droplets shed their negative image
Authors:   AOCS, Guenard rebecca
Published: September 2021

Lipid droplets kill pathogens and serve a crucial role in the body’s immune response. Their accumulation inside the kidney cells could protect the renal system from the damaging effects of a high-fat diet. These findings prove that lipid droplets serve a far greater purpose in the body than once imaged, opening the door for further investigations and possible treatment applications.
FinTech’s business model in Mexico, a preliminary analysis
Authors: Díaz-Peña Luz del Carmen
Published: September 2021

This study analyzes the key success variables in a fintech´s business model. The data was obtained by a questionnaire applied to fifteen Mexican fintech’s. Preliminary results show that the key success variables, according to a significant correlation with the firm´s growth, are: an efficient use of infrastructure, customer-oriented services, competitive wages and security of information; the more common type of fintech operation is the “payments and mobile money services” followed by “crowdfunding” and “investments”. In Mexico, there is not a formal source that makes easier the knowledge of the industry, so the originality of the study lies on the contribution to a better introductory understanding of how fintech´s operate, including other dimensions like the social and environmental ones which had not been considering before. Its limitation is the number of questioned firms, but future complementary studies could be done. It can be concluded that the technological dimension is the most relevant for the industry.
Competencia en el mercado de crédito entre los bancos dominantes en México
Authors: Méndez-Heras Lizethe Berenice , Venegas-Martínez Francisco , Linthon-Delgado Diego Emilio
Published: September 2021

Objetivo: Esta investigación mide el grado de competencia de los bancos que dominan el mercado del crédito en México en 2004-2016. Para ello se utiliza el enfoque no-estructural de las medidas de competencia con base en la teoría de la Nueva Organización Industrial Empírica (NOIE). Metodología: Se estima un modelo de ecuaciones simultáneas con Mínimos Cuadrados Generalizados en 2 Etapas (MCG2E) en datos panel para obtener el estadístico de variación conjetural, el cual mide el grado de coordinación entre los bancos. Resultados: La evidencia empírica obtenida sugiere que los bancos dominantes tienen un comportamiento oligopólico de Cournot en 2004-2016. Implicaciones: Contrario a lo que se esperaba, la investigación también sugiere que el aumento de las comisiones bancarias ha tenido un efecto positivo en la demanda del crédito. Originalidad: Hasta donde los autores saben no se ha realizado un estudio sobre la competencia en el mercado de crédito entre los bancos dominantes en México con base en la NOIE. Recomendaciones: Debido a lo anterior, se proponen en las conclusiones varias recomendaciones en materia de regulación prudencial para que se promueva una mayor competencia. Conclusiones: En el sector crediticio, los bancos en México tienen un elevado poder de mercado con altos márgenes financieros en un oligopolio de Cournot.
Contagio en la volatilidad entre los mercados de capital y de divisas en México y Brasil (2000-2020)
Authors: López Villa Jorge , Sosa Castro Miriam
Published: September 2021

Se analiza el contagio en volatilidad entre los mercados cambiarios y de valores en México y Brasil de enero/2000 a noviembre/2020. La metodología incluye modelos GARCH univariados: GARCH, APARCH, EGARCH y TARCH para el análisis de la volatilidad de las series y modelos multivariados GARCH: DCC y ADCC, para medir los co-movimientos de la volatilidad condicional del mercado de capitales y cambiario, permitiendo determinar la existencia de contagio. Se observa que, en el mercado brasileño, la correlación es más fuerte y estable que en el mercado mexicano, confirmando, al menos un periodo de contagio en cada economía. Las recomendaciones que se desprenden es que, durante periodos de inestabilidad se deben realizar estrategias de cobertura cambiaria o, mantener las posiciones hasta que haya recuperación en los mercados. Las limitaciones es que únicamente se incluyen dos economías latinoamericanas, por lo que, no se analiza el efecto regional. La originalidad radica en la propuesta empírica, el estudio de economías emergentes, que han sido escasamente analizadas, así como, en el aporte de información crucial para las estrategias de diversificación y cobertura de riesgos.
Asymmetric Volatility Relevance in Risk Management: An Empirical Analysis using Stock Index Futures
Authors: Benavides Guillermo
Published: September 2021

The objective of this research work is to show the relevance of asymmetries in estimating volatility. The methodology consists in the application of ARCH-type models and implied volatilities of options (IV) to estimate Value-at-Risk (VaR). These for a portfolio of stock index futures for various time horizons. The empirical analysis is carried out for the futures contracts for the Standard and Poors 500 and Mexican Stock Exchange Indices. According to the results, the IV model is superior in terms of precision compared to the ARCH-type models. It is recommended to use the relevant statistical gains when asymmetries are included with respect to when asymmetries are not used. The referred gains range from 4 to 150 basis points of minimum capital risk requirements. The originality of the present work consists of showing the importance of considering the asymmetric effects with IV and ARCH-type models in volatility forecasts within risk management analysis. It is concluded that the methodology means gains in monetary terms.
Dependence in the Banking Sector of the United States and Mexico: A Copula Approach
Authors: Bucio Pacheco Christian , Villanueva Luis , Gutiérrez Raúl de Jesús
Published: September 2021

The objective of this work is to estimate the patterns of dependence between the yields of the stock prices of the main banks of the United States (US) and Mexico. We estimate the patterns of absolute dependence and tail dependence through copulas of the Archimedean family and the use of rolling windows of 245 days. The data employed come from the daily share prices at closing from January 2, 2015, to December 31, 2020, for seven banks. Our results show that: i) there are patterns of high dependence among the main banks in the US, ii) there are patterns of very low dependence among the main banks in the US and Mexico, and iii) there are patterns of low dependence among the main banks in Mexico. These results have several implications, among them that the high-dependency patterns obtained among major US banks limit the joint selection of these US bank equity assets in an investment portfolio. Although this paper focuses on a small sample of banks, they represent an important portion of the banking sector in both countries. Given the limited literature on this subject in Mexico, our paper contributes to expanding this literature with a novel approach.