bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulações computacionais no ensino de circuitos elétricos: interlocuções com teses e dissertações
Authors: Candia Deiviti Gustavo Moreira de , Heckler Valmir
Published: September 2024

Este trabalho tem por objetivo apresentar um recorte do que a pós-graduação na área de Ensino de Ciências no Brasil comunica sobre a utilização dos recursos computacionais no ensino de eletricidade, em particular, circuitos elétricos. A investigação das perspectivas divulgadas pela comunidade de pesquisadores sobre o uso de recursos computacionais foi realizada por meio de uma revisão da literatura. Essa revisão analisou dissertações e teses publicadas no período de 2005 a 2022, disponíveis no Portal Brasileiro de Acesso à Informação Científica (oasisbr). A análise qualitativa das 19 dissertações e 1 tese neste estudo revelou o potencial das simulações computacionais em circuitos elétricos para aprimorar a compreensão de fenômenos abstratos e possibilitar atividades experimentais complexas. É essencial utilizar essas simulações de forma complementar às práticas de laboratório, promovendo a interação entre os alunos e instigando a discussão dos conteúdos, por meio da implementação de roteiros nessas atividades.
Uma UEPS para a Física de Neutrinos aplicada em tempos de pandemia
Authors: Gomes Francisco Elias , Alvarenga Flávio Gimenes
Published: September 2024

Neste artigo, é apresentado um produto educacional elaborado para o ensino da física de neutrinos no formato de uma Sequência Didática (SD), inspirada nas Unidades de Ensino Potencialmente Significativas (UEPS), que são sequências didáticas baseadas nos pressupostos da Teoria da Aprendizagem Significativa (TAS) de David Ausubel. O objetivo do artigo é trazer temas de Física Contemporânea, especialmente Neutrinos, para o ensino médio. Esperamos que os alunos tenham uma boa compreensão do que são as partículas fundamentais, especialmente os neutrinos. A metodologia utilizada foi a metodologia ativa estruturada em uma UEPS. O produto educacional foi aplicado por meio de aulas remotas no período da pandemia de coronavírus (covid-19), em uma turma do terceiro ano do ensino médio de uma escola pública no município de Mutum-MG. A estruturação do produto educacional será detalhada e os principais resultados de sua aplicação serão discutidos.
Práticas epistêmicas no contexto da iniciação científica: ensaios sobre o desenvolvimento da argumentação
Authors: Gonzatti Sônia Elisa Marchi , Lima Noeli Jung Friedrich de
Published: September 2024

Este trabalho é fruto de uma pesquisa de mestrado na modalidade profissional em Ensino de Ciências Exatas. Dentre os resultados empíricos emergentes, esta análise irá destacar as contribuições da iniciação científica para o desenvolvimento de práticas epistêmicas ligadas à dimensão social da ciência. Os encontros de iniciação científica foram realizados em uma escola pública estadual de Mato Grosso, com uma turma de 3º ano do Ensino Médio. O quadro teórico de análise dialoga com contribuições de pesquisas sobre o desenvolvimento do pensamento crítico e com diretrizes sobre o ensino por investigação. Os dados empíricos emergiram de grupos focais e dos diários de campo dos estudantes e da pesquisadora. Em termos gerais, foi possível concluir que a iniciação científica oportunizou a vivência de práticas epistêmicas ligadas à produção e comunicação do conhecimento. Entre elas, destacam-se o desenvolvimento da argumentação em diferentes etapas das pesquisas realizadas pelos estudantes.
Um quiz criado na plataforma Proprofs para Ensino e Avaliação de Conteúdo da Ondulatória fundamentado na Teoria dos Campos Conceituais
Authors: Feitosa Bruno Emanuel Mendes , Filho Francisco Eduardo de Sousa , Dantas Claudio Rejane da Silva
Published: September 2024

O trabalho busca validar uma sequência didática fazendo uso de um quiz para apoiar o estudo sobre Ondas em uma turma de Ciências do 9º ano do Ensino Fundamental em Farias Brito, CE. O aporte teórico foi a Teoria dos Campos Conceituais de Gérard Vergnaud. O estudo foi qualitativo usando questionário estruturado com o recurso quizze. A intervenção ocorreu em 5 encontros, dos quais 3 foi presencial e os outros 2 de maneira remota, acompanhado pelo professor através das plataformas digitais. Evidenciou-se que a participação e o engajamento dos alunos nas atividades propostas aumentaram positivamente. Através dos resultados obtidos nas respostas e nos debates em sala, pode-se diagnosticar uma evolução dos alunos em relação aos conceitos estudados, porém, para se obter o desenvolvimento de um Campo Conceitual é necessário que o indivíduo vivencie diversas situações e problemas diferentes para o processo duradouro de um campo conceitual da física.
O ensino da Astronomia nos anos finais do Ensino Fundamental: influências na Formação Continuada de professores
Authors: Batista Michel Corci , Diniz Telma Augusta , Pereira Lucas Forlin
Published: September 2024

Este artigo, fruto de um trabalho maior, está centrado no Ensino da Astronomia e tem o objetivo de investigar os contributos atrelados à ação docente de professores, oriundos de sua participação em um curso de Formação Continuada em Astronomia, em 2018. A metodologia incluiu a realização de uma entrevista semiestruturada com os participantes do curso, seguida de uma Análise de Conteúdo Categorial, de Bardin (2016). Os resultados destacam a relevância da Astronomia como uma disciplina que desperta a curiosidade dos alunos e sua interconexão com outras áreas do conhecimento. Além disso, os professores relataram como o curso de Formação Continuada influenciou positivamente suas práticas de ensino, permitindo-lhes adquirir conhecimentos sólidos em Astronomia e desenvolver estratégias pedagógicas eficazes. O estudo demonstra a importância da formação continuada para capacitar os professores a oferecer uma educação de qualidade em Astronomia nas escolas, promovendo a compreensão do universo e incentivando o pensamento crítico dos alunos.
Do céu iluminado ao céu estrelado: planetários como ferramenta de conscientização sobre a poluição luminosa
Authors: Silva Fábio Calabrio Evangelista da , Iachel Gustavo
Published: September 2024

Este artigo explora a utilização de planetários como ferramentas educacionais para abordar o problema da poluição luminosa. Examina o impacto da poluição luminosa no meio ambiente e na saúde humana e discute como os planetários podem conscientizar sobre esse problema por meio de experiências imersivas. O artigo destaca o papel dos planetários em simular o céu noturno intocado, mostrando a beleza das noites estreladas e demonstrando os efeitos negativos da poluição luminosa. Também explora estratégias educacionais utilizadas pelos planetários para envolver os visitantes em discussões e ações para mitigar a poluição luminosa. Ao promover a compreensão e inspirar esforços coletivos, os planetários têm o potencial de impulsionar mudanças positivas e uma relação mais sustentável entre a humanidade e o céu noturno.
Securing Clinical Data in Honduras: Exploring Cybersecurity Regulations and the Role of Blockchain
Authors: García Jorge Alberto
Published: September 2024

The existence of cybersecurity regulations in Honduras aimed at safeguarding clinical data remains uncertain, leaving the populace’s health information vulnerable due to the absence of robust legal frameworks. This study sheds light on the current landscape concerning health information protection in the country, underscoring its profound impact on securing medical information systems and the realm of Internet of Things (IoT). It underscores the potential of blockchain technology to provide an innovative solution to address security challenges in this domain. Employing a systematic approach, the research delineates a timeline to elucidate the evolution of legal measures against cybercrime in Honduras, consolidating pertinent governmental documents associated with cybersecurity and the protection of medical data. Furthermore, it underscores the healthcare sector’s susceptibility to cyber threats and the primary privacy apprehensions pertaining to IoT applications in medicine. The study concludes that Honduras lacks a dedicated data protection statute, posing a significant impediment to cybersecurity regulatory efforts. This legal void impedes the effective implementation of measures to safeguard clinical information and shield it from potential cyber risks amidst the proliferation of IoT initiatives and healthcare-related ventures. Nonetheless, this circumstance may present an opportunity for the adoption of technologies such as blockchain. By enabling the establishment of tailored regulatory frameworks, blockchain can adapt to its unique attributes, thereby facilitating its integration in fortifying clinical data protection and enhancing overall cybersecurity protocols.
Design of a Customized Thumb Prosthesis: Focus on Functionality and Comfort
Authors: Coello Martinez Celine Jireh , Cáceres Lagos Fernanda de Lourdes
Published: September 2024

This research focuses on addressing the scarcity of personalized and affordable prostheses in Honduras by designing and developing a functional prosthesis for a thumb. The general objective was to design a model suitable for 3D printing adapted to the specific needs of a patient who had her index and thumb fingers amputated. To achieve this, an integral methodology was employed, ranging from an exhaustive literature review of current solutions to detailed material evaluations, including interviews with patients and medical experts, SolidWorks modeling, and simulations. The result was the successful design of a functional prosthesis prototype, with the selection of intentionally 3D printable materials to ensure comfort and functionality. In conclusion, this research demonstrates the viability of addressing the scarcity of personalized prostheses through innovative approaches and comprehensive design methodologies, with a focus on effectiveness and streamlining the process.
Effect of Sweep on a Pitching Finite Wing
Authors:   German Aerospace Center (DLR), Gardner A. , Merz C. , Wolf C.
Published: September 2024

An investigation was performed into the effect of positive and negative sweep angle on the boundary layer transition and dynamic stall behaviour of a finite wing. The finite wing had a 6:1 aspect ratio, modern (SPP8) tip shape and positive twist, moving the maximum load on the wing away from the wind tunnel wall. Experiments were performed with sweep A=±30° and A=0° for static polars and sinusoidal pitching. The positively twisted wing shows a similar S-shaped boundary layer transition on the pressure side to that previously seen for helicopter rotor blades in hover. The transition positions on the suction side of the wing are comparable for the same local angle of attack at all values of the sweep L at each of the three pressure sections, and for dynamic pitching motions a hysteresis around the static transition positions is seen. Sweeping the wing led to later stall and higher maximum lift for both static polars and dynamic stall, except for a single case. The negative aerodynamic damping is worse for the swept wing than for the unswept wing, except where the delay of stall led to the flow remaining attached.
Three-Component Reverse Flow Measurements on a Mach-Scale Rotor at High Advance Ratios
Authors:   University of Maryland, Smith Luke ,   Glenn L. Martin Wind Tunnel, Lind Andrew , Bauknecht André , Wang Xing , Jones Anya
Published: September 2024

Reverse flow is the source of several unsteady effects that complicate load predictions for high advance ratio rotorcraft. As a way of improving load predictions, an ongoing series of experiments has been aimed at gaining a physical understanding of the unsteady aerodynamics of the reverse flow region. The current work contributes phase-averaged, three-component velocity field measurements collected on a rotor at high advance ratios. Stereoscopic particle image velocitmetry (PIV) was performed on a Mach-scale rotor across three advance ratios (0:6 ≤ μ ≤ 0:8), three radial stations (0:3 ≤ r/R ≤ 0:6), and one collective (θ0 = 10°). The present analysis focuses on how the reverse flow dynamic stall vortex, which results from flow separation about the sharp geometric trailing edge of a rotor blade in reverse flow, evolves over time in three dimensions. For a constant advance ratio, the size of the reverse flow dynamic stall vortex increases with decreasing radial station, creating a gradient in vorticity along the blade span. Tip-to-root radial flow, the amount of which increases for inboard radial stations, was also associated with the development of the reverse flow dynamic stall vortex. The current work postulates that due to an increase in radial flow, inboard radial stations are subject to a greater radial transport of vorticity than outboard sections and, in turn, produce less dimensional vorticity than outboard sections at the same convective time. Coupled with previous experimental models of reverse flow, the current work represents an important step in identifying the dominant unsteady characteristics of the reverse flow region and is designed to inform a low order model of rotors at high advance ratio.
Heavy Class Helicopter Fuselage Model Performance Improvement using Vortex Generators
Authors:   Italian Aerospace Research Centre - CIRA, Gregorio Fabrizio
Published: September 2024

Wind-tunnel tests of a heavy-class helicopter model were carried out to evaluate the effectiveness of passive flow control system in alleviating the fuselage parasite drag. An array of counter rotating vortex generators was selected to reduce/remove the flow separation occurring on the rear loading ramp responsible of the high pressure drag. Different technical solution for the VGs design and location were selected with respect to previous work. The basic fuselage geometrically scaled 1:7 of a heavy class helicopter was investigated with and without passive flow control system. The comprehensive experimental campaign involved the use of different measurement techniques. Indeed, pressure measurements and stereo particle image velocimetry surveys were performed to gain a physical insight about the results of load measurements. This paper addresses the promising results obtained during the wind-tunnel campaign, since significant drag reduction was achieved for a wide range of fuselage angles of attack and side slip angles without the detriment of the other aerodynamic characteristics.
Comparison of VortexWake, VVPM and CFD Aeromechanics Computations of the Boeing 222 Proprotor
Authors:   NASA Ames Research Center, Bowen-Davies Graham
Published: September 2024

An aeromechanics investigation was conducted for the Boeing 222 proprotor test in transition orientation with the comprehensive analysis code RCAS comparing vortex wake, Viscous Vortex Particle Method (VVPM) and Helios™ (CFD) calculations. The results include the calculations of rotor trim and rotor oscillatory structural loads for a proprotor in near axial orientation at high speed, high incidence transition and helicopter-like edgewise orientation. VVPM and Helios calculations gave the same wake physics for the isolated rotor and resulted in similar hub moments and blade loads sensitivities to cyclic inputs. Helios and VVPM calculations differed during BVI wherein the lifting line model of VVPM is less accurate. Vortex Wake, without tuning, produced inaccurate rotor wake trajectories, and the low speed, high incidence calculations of trim and loads were inaccurate. Helios was used to evaluate the effect of the nacelle and tunnel walls on the trim angles. The nacelle affected the wake trajectory and impacted trim, but the changes to loads was small. Modeling the rotor in close proximity to the tunnel ceiling had the opposite affect on trim to the effect relative to the Glauert wall corrections. The effect of the tunnel wall corrections calculated by Helios was smaller than the equivalent (Glauert) correction made to VVPM.
Shape Optimization of Rotorcraft Airfoils Using a Genetic Algorithm
Authors:   Pennsylvania State University, Stanko Jason ,   University of Tennessee, Coder James , Schmitz Sven
Published: September 2024

In this work, a genetic algorithm was implemented to perform an airfoil shape optimization with constraints applied to the airfoil cross-sectional area and pitching-moment coefficient. Constraints are enforced through the use of an augmented Lagrange penalty function. The design variables are formed through a class shape transformation approach with orthogonal, polynomial basis modes. The use of an orthogonal basis provides decreased levels of multicollinearity in higher-order design spaces, while still maintaining the completeness of lower-order spaces. The optimization methodology is demonstrated on the tip airfoil of a UH-60A baseline rotor. The design trade-offs of a new tip airfoil are investigated where the optimized tip section shows improvements in forward-flight performance in exchange for a small reduction in the rotor's stall margin.
Higher-order Simulations of a Compound Helicopter using Adaptive Mesh Refinement
Authors:   University of Stuttgart, Öhrle Constantin , Schäferlein Ulrich , Keßler Manuel , Krämer Ewald
Published: September 2024

Higher-order methods and adaptive mesh refinement (AMR) have demonstrated their added value to numerical simulation of a variety of aerodynamic problems, including rotorcraft flow. Within this paper, the implementation of a higher-order spatial WENO (Weighted Essentially Non-Oscillatory) method for flux reconstruction and an AMR method for grid refinement into a comprehensive and approved rotorcraft simulation framework is discussed. A significant increase in computational efficiency by factor 15 can be achieved using higher-order methods. AMR allows a considerable reduction of required overall grid cells, and thus computational effort, to represent the occurring flow phenomena with equivalent accuracy. The rotorcraft simulation framework is applied to simulate a highly complex compound helicopter geometry with a variety of challenging phenomena. Flight mechanic trim and elastic blades are taken into account for a physical representation of the flight state. The benefit of the AMR technique in combination with the higher-order methods for an isolated rotor in hover and a complete helicopter configuration in cruise flight is investigated. A robust application of the AMR implementation is demonstrated, which shows a reduction of computational cost by 50% at high advance ratio cases without a noticeable loss of accuracy.
Engineering Models for Inertially-Fixed Forces Caused by Hingeless Rigid Rotors in Non-Uniform Inflow: A Problem for Compound Helicopters
Authors:   Aircraft Research Association, Smith Harry ,   cbec eco-engineering UK Ltd, Gillies Eric ,   University of Glasgow, Zarev Angel , Green Richard
Published: September 2024

A novel application of harmonic wake methods for propellers at incidence have applications for compound helicopters. Any hingeless rotor subject to non-uniform incident velocity will produce a constant force in inertially-fixed axes (i.e., reacted on the non-rotating support) - though this phenomena is well-documented, engineering-level models for prediction of this force are generally poor, and tend to utilise assumptions that have little physical basis. To avoid utilising these assumptions, a harmonic load/wake model is presented that affords the ability to model blade-level unsteadiness without time-marching, includes three-dimensional blade effects, and allows whole-disc load resolution at the same computational cost as the referenced current 'best practice' models. Furthermore, the fundamental equations that convert harmonic blade loads into steady inertially-fixed forces are reviewed, and shown to be missing a large component of the force resolved into inertially-fixed axes. Finally, detail is provided of a current wind tunnel experiment aiming to provide validation for the harmonic wake model.
Biopsychosocial Model Analysis of a Recurrent Guillain–Barré Syndrome Patient’s Recovery
Authors: Naik Prashant P. , Phadke Rutuja A. , Kulkarni Amogh R. , Nair Vishagh K.
Published: September 2024

Guillain–Barré syndrome (GBS) is an autoimmune disease that generally follows a monophasic course and typically does not recur. This case report explores the application of the biopsychosocial model in the context of a 46-year-old patient who experienced GBS for the second time in 2 years. It highlights the predisposing, precipitating, perpetuating, and protective factors affecting the patient’s biological, psychological, and social aspects during their recovery journey. The patient’s excellent socioeconomic status, social activity, and strong family support along with vigorous physical therapy played a crucial role in their remarkable recovery.
Forensic Analysis of Sexual Dimorphism from Facial Photographs
Authors: Panwar Prachi , Sharma Tina , Gautam Archana , Sankhla Mahipal Singh
Published: September 2024

Background:

Techniques for identifying facial features and proving the individuality of a person’s facial features are used in forensic anthropology.

Aims and Objectives:

A common method in this area is cranial anthropometry, which has uses in facial reconstruction, locating unidentified remains, and identifying criminal suspects.

Materials and Methods:

A study analyzed 200 standard full-face photographs of 50 males and 50 females to compare frontal and lateral facial images and identify male and female facial traits. We located landmarks and measured the distances between them. The data were analyzed using statistical tests like t-tests and analysis of variance (ANOVA) tests.

Result:

The results showed that in 100% of the suggested measurements for both males and females, there were no statistically significant differences (P > 0.05) between frontal and lateral views. The ANOVA test, however, showed that all suggested measurements showed differences in the lateral aspect, while only 76.92% of them showed differences between the male and female groups in the frontal aspect.

Conclusion:

In conclusion, statistically significant differences were found, rejecting the null hypothesis of equal means, when the level of significance (α) was lower than the P value (0.05). On the other hand, the null hypothesis was accepted when statistically insignificant differences were found and the level of significance was higher than the P value. Although there were differences between males and females in different views, the distances between landmarks in frontal and lateral views of the same person were generally similar. Measurements taken in the lateral aspect were more accurate and displayed greater sexual dimorphism variation compared to those taken in the frontal aspect.
Geoforensic Methods for Detecting Clandestine Graves and Buried Forensic Objects in Criminal Investigations – A Review
Authors: Narreddy Vaishnavi
Published: September 2024

Geoforensic techniques are being deployed in searches for hidden objects to counteract the shortcomings of conventional blunderbuss methods. Processing of crime scenes during searches for clandestine graves and buried objects is often destructive. Manual excavation and other invasive methods are restricted in many contemporary situations, and the location of a body is essential for forensic investigations. Geoforensics and geophysical surveys are important tools for assisting law enforcement agencies in locating crime scenes, clandestine graves, drugs, artifacts, hazardous waste, and illegal weapons and ammunitions stored underground in preparation for terrorist attacks. Geoscience search techniques such as the geoforensic search strategy are among many models used to help find mass graves, locate missing persons, and verify information acquired from incomplete intelligence. Trace amounts of soils, sediments, and other geological materials can provide geolocations and aid in the development of a primary search area. Forensic geoscience techniques and equipment such as metal detectors, magnetic surveys, electromagnetic conductivity surveys, ground penetrating radar surveys, augering (probing), detector dogs surveys, and gravity and seismic fluctuation monitoring are discussed in this paper. In addition to the location of potential graves and ambush sites, the soil beneath the decomposing cadavers can be used to predict the postmortem interval for the deceased. Soil information and geo-mapping data can provide productive intelligence for military and national security agencies. Antiquities crimes and crimes involving gemstones in which the evidence passes through many hands can be traced back to the place of origin by checking for their geo-morphology. Serious crimes, including murder, genocide, and terrorism, can be prevented by the use of operational and decisive geoforensic techniques. This paper highlights the multidisciplinary information exchange that occurs between forensic burial science, forensic geology, and trace evidence in criminal investigations. The paper also focuses on geoforensic approaches to clandestine grave searching, underwater investigations, forensic engineering fallacies, military intelligence, ambush detection, and weapons mining.
Human Bite Mark: A Digital Analytical Pilot Study
Authors: Suresh Nidhi Susan , Shah Jigna S
Published: September 2024

Background:

Bite mark identification is based on the individuality of a dentition and helps in identifying the perpetrator. The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. CBCT has been used in registering bite mark on food material. To our knowledge this is the first study where CBCT is used to register bite mark from human forearm.

Aims and Objective:

To signify the potential of CBCT in registering and analysing the bite mark on human skin and to analyse various identifying parameters.

Materials and Method:

60 subjects of either sex were asked to bite their own forearm and alginate impression of the maxillary and mandible dentition was taken and cast was poured. Both bitemark and cast was subjected to CBCT scanning and parameters like arch shape, inter canine width, mesio distal dimension of anterior teeth, and individual characteristics like rotation, buccal/lingual tilting of teeth was noted and compared and assigned a score using simplified version of ABFO scoring system.

Results:

Highly significant result with 56.6% definite match, 26.66% probable match and 16.66% possible match were obtained using CBCT.

Conclusion:

CBCT is a non-destructive, accurate, efficient, objective and reproducible method. Out of all parameter mesio-distal dimension of teeth is the best parameter to judge the bitemark on skin.
A Segmentation-based Automated Calculation of Patient Size and Size-specific Dose Estimates in Pediatric Computed Tomography Scans
Authors: Abdulkadir Muhammad Kabir , Osman Noor Diyana , Achuthan Anusha , Nasirudin Radin A. , Ahmad Muhammad Zabidi , Zain Noor Hasyima Mat , Shuaib Ibrahim Lutfi
Published: September 2024

Background and Purpose:

Size-specific dose estimates (SSDE) have been introduced into computed tomography (CT) dosimetry to tailor patients’ unique sizes to facilitate accurate CT radiation dose quantification and optimization. The purpose of this study was to develop and validate an automated algorithm for the determination of patient size (effective diameter) and SSDE.

Materials and Methods:

A MATLAB platform was used to develop software of algorithms based on image segmentation techniques to automate the calculation of patient size and SSDE. The algorithm was used to automatically estimate the individual size and SSDE of four CT dose index phantoms and 80 CT images of pediatric patients comprising head, thorax, and abdomen scans. For validation, the American Association of Physicists in Medicine (AAPM) manual methods were used to determine the patient’s size and SSDE for the same subjects. The accuracy of the proposed algorithm in size and SSDE calculation was evaluated for agreement with the AAPM’s estimations (manual) using Bland–Altman’s agreement and Pearson’s correlation coefficient. The normalized error, system bias, and limits of agreement (LOA) between methods were derived.

Results:

The results demonstrated good agreement and accuracy between the automated and AAPM’s patient size estimations with an error rate of 1.9% and 0.27% on the patient and phantoms study, respectively. A 1% percentage difference was found between the automated and manual (AAPM) SSDE estimates. A strong degree of correlation was seen with a narrow LOA between methods for clinical study (r > 0.9771) and phantom study (r > 0.9999).

Conclusion:

The proposed automated algorithm provides an accurate estimation of patient size and SSDE with negligible error after validation.
Preparation of new compounds with anticancer properties via the reaction of Kryptofix 5 with two organic acceptors
Authors: M Ali Mahmoud , M.A. Hussein Mohamed , M. Metwally Dina , F.  Alkhuriji Afrah , Song Lujie , Sulaiman Alshaya Dalal , Fayad Eman , Ali Mohamed
Published: September 2024

The new designed complexes via CT interaction between kryptofix 5 and two organic acceptors to introduce basic data that can be used to assessment of crown ether and tested the final complexes against cancer cells. This target was achieved by synthesis of a new CT- complexes of kryptofix 5 as a type of mixed nitrogen–oxygen crown ethers with π-acceptors as (2 hydroxy-3.5-dinitrobenzoic acid and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone). These obtained complexes were structurally characterized in both solid and liquid state via various chemical methods as elemental analysis, FT-IR, NMR, and UV–Visible spectroscopy, thermal degradation and physical properties were calculated. Finally, the CT complex was also tested for its anticancer activity against two human cancer cell lines; colon cancer CaCo2 and liver cancer cell line (hepG2).
KEY WORDS: Anticancer, Kryptofix 5, HDNS, DDQ, Spectroscopy
Bull. Chem. Soc. Ethiop. 2024, 38(6), 1639-1651.                                                          
DOI: https://dx.doi.org/10.4314/bcse.v38i6.11
Synthesis of substituted 2-amino oxazoles with their cobalt(II) and platinum(IV) complexes and evaluation of their biological activity
Authors: Zuhair Husain Amra , S. Al-Jawaheri Yassir , Y. Al-Assafe Amaal
Published: September 2024

Many applications of green synthesis in the field of environment and biomedicine aiming at decreasing the use of toxic chemicals through utilizing of plants which are safe. In this study, at 0.1 M concentration of copper sulfate (CuSO4.5H2O), CuNPs were prepared and identified by changing the blue color into green color (ethanolic extract) and from blue color to black color (water extract) and the spectrophotometric detection of ultraviolet and infrared spectra. X-Ray diffraction (XRD) pattern was utilized to confirm the crystal structure of CuNPs. The morphology and size of the CuNPs was measured by a high-resolution transmission electron microscope (HR-TEM). Energy dispersive X-ray (EDX) was used for identification of the elemental composition of CuNPs involving copper and oxygen. Field emission scanning electron microscopy (FESEM) was utilized to confirm the shape of prepared copper nanoparticles. In vitro antibacterial activity was tested using two methods including desk diffusion assay considering zones of inhibition and minimum inhibitory concentration (MIC) against six types of certain bacterial types (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Staphylococcus aureus, Streptococcus pneumoniae and Enterococcus faecalis). The results showed potent inhibitory activity of copper nanoparticles (CuNPs) and water extract (Ext. 2) against all bacterial strains.
KEY WORDS: Copper nanoparticles, Piper Longum, Extract, Synthesis, Antibacterial
Bull. Chem. Soc. Ethiop. 2024, 38(6), 1667-1680.                                                           
DOI: https://dx.doi.org/10.4314/bcse.v38i6.13
Synthesis of some metal ion complexes of new imidazole derivative, characterization, and biological activity
Authors: A.H. Abdullah Sallal , Sataar Shia Jaafar
Published: September 2024

Imidazole complexes with high biological activity for some metal complexes prepared by a new imidazole ligand from the reaction of a 1,3-oxazole derivative with hydroxylamine and utilizing this ligand in the preparation of some metal ion complexes. Many of the techniques available for all prepared compounds, such as elemental analysis (CHNS), (FT-IR), (UV-Vis) spectra, and 1H-NMR spectra, will be used in the diagnosis of these complexes, and the forms  of the complexes will be deduced from the results obtained. The outcomes demonstrated that the octahedral geometries of all the produced complexes, except for the copper and palladium complexes, which were square planer shapes. The antimicrobial activity of both the ligand and its metal ionic complexes against various microbes was evaluated.
KEY WORDS: Imidazole, Oxazole, Spectral data, Bioactivity
Bull. Chem. Soc. Ethiop. 2024, 38(6), 1681-1690.                                                           
DOI: https://dx.doi.org/10.4314/bcse.v38i6.14
Preparation and characterizations of metal-based complexes derived from the reaction of trizma base with Mg(II), Ca(II), and Ba(II) ions
Authors: Majid A. Adam Abdel , S. Refat Moamen , Mohammed Alsuhaibani Amnah , Y. El-Sayed Mohamed
Published: September 2024

Trizma base is a small organic compound that possesses one amino group (-NH2) and three hydroxyl groups (-OH). Three products of trizma base as a ligand were prepared from the reaction of Mg(II), Ca(II), and Ba(II) ions with the ligand at a temperature of 65 °C and stoichiometry of 1:1 (ligand to metal ion). The trizma ligand was referred to as Tris, and its complexes with Mg(II), Ca(II), and Ba(II) ions were referred to as Product 1, Product 2, and Product 3, respectively. After the preparation of the products, they were characterized by several analytical methods, including spectroscopies [Fourier-transform infrared (FT-IR) and ultraviolet/visible (UV-visible)], thermogravimetry (TG), elemental analyses, X-ray diffraction (XRD), and scanning electron microscope with environmental mode (ESEM). Analytical results suggested that Tris ligand captured the investigated metal ions using the amino group (-NH2) and one hydroxyl group (-OH) forming complexes with general composition of [MgTris(H2O)4]·Cl2·2H2O (Product 1), [CaTris(H2O)4]·Cl2·2H2O (Product 2), [BaTris(H2O)4]·Cl2·H2O (Product 3). The corresponding gross formulas for these products were C4H23NO9MgCl2 (324.34), C4H23NO9CaCl2 (340.11), and C4H21NO8BaCl2 (419.37 g/mol), respectively. SEM micrographs captured at high levels of magnification (×100,000) clearly illustrate variations in the morphology of products 1, 2, and 3.
KEY WORDS: Trizma base, Spectral analysis, Thermogravimetry, SEM micrographs
Bull. Chem. Soc. Ethiop. 2024, 38(6), 1791-1801.                                                    
DOI: https://dx.doi.org/10.4314/bcse.v38i6.22
Sensitive analysis of some detrimental volatile organic compounds in fabric, carpet and air freshener using solid phase extraction and gas chromatography–mass spectrometry
Authors: M. Ali Hazim , Rizwan Khan Mohammad , A. Essawy Amr , El Aziz A. Nayl Abd , Ibrahim Hossieny , Gomaa Hassanien , Gamal Mohammed , H. Alruwaili Yasamiyan , B. Al Rwilly Ghazal , H.A. Hasanin Tamer
Published: September 2024

Benzene, toluene, ethylbenzene and xylene are known to be lethal environmental contaminants that have carcinogenic and mutagenic influences in human being while styrene and benzaldehyde have a neurotoxic effect. In other hand, the constituents of air freshener considered as a probable source of volatile organic compound. In the present work, a solid phase extraction and gas chromatography–mass spectrometry (GC-MS) technique has been optimized and applied to the fabric, carpet and air freshener samples to determine the trace amounts of benzene, toluene, ethylbenzene, xylene, styrene and benzaldehyde. The SupelcleanTM ENVITM - 18 cartridge with dichloromethane extracting solvent were found to be the optimal procedures. The system presented excellent performance in terms of limit of detection (0.08-0.61 ng/mL), coefficient of determination (0.994-0.997), precision with the relative standard deviation values ranging from 0.05-2.57%. According to the results, the concentration of benzene, toluene, ethylbenzene, xylene, styrene and benzaldehyde in fresheners’ samples was found in the range 0.03-53.27, 0.03-7.12, 0.02-6.51, 0.05-96.44, 0.04-7.06 and 0.22-23.02, respectively. The excellent recovery values were also obtained up to 99.93%. The SupelcleanTM ENVITM -   18 GC-MS system was found to appropriate for the monitoring of analytes in fabric, carpet, air freshener samples, and other samples of the similar constituents.
KEY WORDS: BTEX, Styrene, Benzaldehyde, Air freshener, Solid phase extraction, Gas chromatography–mass spectrometry
Bull. Chem. Soc. Ethiop. 2024, 38(6), 1543-1556.                                                          
DOI: https://dx.doi.org/10.4314/bcse.v38i6.4
Heavy metal ions in polluted water removable by synthesising a new compounds for dithiocarbamate derivatives
Authors: S. Al-fahdawi Aeed , K. Mohamed Shaaban , Potgeiter Herman , Alfutimie Abdullatif
Published: September 2024

Metal ion poisoning in water and industrial effluents threatens ecosystems and human health. The development of efficient metal ion removal technologies has garnered attention in recent years. This work synthesizes and characterizes dithiocarbamate complexes as metal ion scavengers. Used to make dithiocarbamate ligands. Different metal salts were added to carbon disulfide and the proper amines to initiate substitution reactions. The complexes were characterized using FTIR, UV-Vis, mass spectroscopy, 13C-, 1H-NMR, magnetic susceptibility, melting point, and electrical conductivity molar EC. Data from spectroscopy and analysis indicate the development of two-type macrocyclic complexes with the formula [M(L)]2, where M = FeII, CoII, and ZnII ions. Tetrahedral geometries around the metal core and the second general formula [M(L)(H2O)2]2, where M = MnII, NiII, CuII, suggested octahedral structures. Heavy water pollution has been removed using this essential ligand. Metal ion scavenging of 96–98% was possible with the produced dithiocarbamate complexes. This work developed unique and efficient strategies for metal contamination removal from aquatic settings, promising environmental remediation and human health protection. Optimizing synthesis conditions and scaling up operations are needed to fully use these compounds in real-world applications.
KEY WORDS: Dithiocarbamate ligand, Transition metal complexes, Spectral characterization, Coordination chemistry, Dithiocarbamate complexes, Scavenger heavy metal ions
Bull. Chem. Soc. Ethiop. 2024, 38(6), 1583-1593.                                       
DOI: https://dx.doi.org/10.4314/bcse.v38i6.7
Evaluation of Physicochemical and Antibacterial Properties of Ethanolic and Gel Extracts of Common Wireweed (Sida acuta Burm.f.)
Authors: Okafo S. E. , Enemchukwu C. , Iyamah F. C. , Osuala J. O. , Anie C. O.
Published: September 2024

Man has used medicinal plants as remedies for several human diseases for centuries. This paper therefore evaluates the physicochemical and antibacterial properties of ethanolic and gel extracts of common wireweed (Sida acuta Burm.f.) using appropriate standard techninques. The filtrate was concentrated to a semi-solid mass (extract) and the antibacterial activity of the extract against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli were assessed using the agar well diffusion technique. The gels have good homogeneity, and spreadability, and are easily washable. The pH ranges between 5.8 and 6.3 and is within the normal skin pH range (4.0-6.8). The extrudability ranges from 45 to 70%. The viscosity of the gels is between 6178.6 mPas and 59,343 mPas and they are shear thinning systems. The gels prepared using Sida acuta ethanolic extract have antibacterial activity that is comparable to that of the extract alone. Gells formulated using carbopol were comparable to those prepared using HPMC.
Hazard and Health Risk Assessment of Heavy Metals in Non-Alcoholic Beverage Consumed in Abia State, Nigeria
Authors: Ogoko E. C. , Aletan U. I. , Osu C. I. , Kelle H. I. , Iroegbulem I. , Emeziem D. , Fagbohun A. A. , Ogoko N. I. , Adams A. E.
Published: September 2024

The quality of non-alcoholic beverages consumed in Aba, Abia State, southeastern Nigeria and health risk assessment of heavy metals required periodic evaluation so as to avert potential health hazard. Hence, the objective of this paper as to evaluate the hazard and health risk assessment of heavy metals in non-alcoholic beverages consumed in Abia State, Nigeria using health risk assessment models. Heavy metals concentrations were determined using atomic absorption spectrophotometer (Agilent 280FS AA). The average heavy metal concentrations of non-alcoholic drink samples ranged from 0.040 - 1.132 mg/l in ascending order of Zn < Cd < Co < Cu < Pb <Cr < Mn < Fe respectively. The average concentrations of Mn, Cr, Cd, Fe and Pb exceeded the standard maximum permissible limits for drinking water quality. The values of estimated daily intake for Cd, Fe, Pb, Cr, Mn and Zn were within acceptable provisional tolerable daily intake and safe limits. The hazard quotient (HQ) values for Mn, Cr, Cd, Zn and Fe were within safe limit (< 1.0), except for Co and Pb that had HQ values greater than one in over 37.5 % of the total samples, indicating associated potential chronic health risks. Hazard index of 72.5% of all the non-alcoholic drink samples were above the safe limit (>1.0), signifying potential chronic health risk as a result of combine effects of these heavy metals. The incremental life cancer for Cr, Cd and Pb ranged from 2.59E-05 - 1.79E-03, 1.35E-04 – 2.81E-04 and 3.92E-06 - 3.24E-05 respectively. The incremental life cancer values of Pb were within the recommended safe limit of not greater than 1.0 × 10-4 and has the least likelihood of any potential cancer risks. However, Cd, and Cr had cancer risk values higher than the save limits, indicating potential life cancer health risks in both children and adult population.
Influence of pH Variations on Biofilm Formation of Bacillus thuringiensiskurstaki HD1 on Polystyrene Surfaces
Authors: Muhammad M. H. , Sulaiman M. A. , Zandam N. D.
Published: September 2024

Biofilm formation enhances microbial survival, growth, nutrient access, biocide resistance, productivity, interactions, and stability. Bacillus thuringiensis kurstaki (Btk) HD1 is used as a biopesticide against lepidopterans (moths and butterflies). Thus, the objective of this paper is to evaluate the influence of pH variations on biofilm formation of Bacillus thuringiensis kurstaki HD1 on polystyrene surfaces across a range of pH levels from 1 to 14. The results demonstrated a clear pH-dependent trend in biofilm production. Biofilm formation was optimal between pH 4 and pH 9, with the highest production at pH 4. In contrast, extreme pH values (1, 10, 11, 12, 13, and 14) resulted in reduced biofilm formation. The study highlights the significant influence of pH on biofilm formation by Btk HD1, with optimal biofilm production occurring within a pH range of 4 to 9. These findings suggest that maintaining environmental pH within this range could enhance the efficacy and stability of Btk HD1 as a biopesticide.
Evaluation of Physicochemical Parameters, Total Bacteria Count and some Heavy Metal Levels in Soil from Automobile Workshop Activities at Nnewi Local Government Area, Anambra State, Nigeria
Authors: Madukasi E. I. , Agbazue O.
Published: September 2024

Disposal of used motor oil and chemical substances on land leads to loss in soil quality by minimal abundance and variety of microorganisms in soil. The objective of this paper was to evalaute the physicochemical parameters, total bacteria count and some heavy metal levels in soil from automobile workshop activities at Nnewi Local Government Area, Anambra State, Nigeria. Using field survey and  appropriate standard laboratory analyses, the results showed that the control uncontaminated soil samples recorded high bacteria count (6.9 x106 cfu/g). The available soil nitrogen(9.0), soil nutrients nitrate (15.10) and phosphorous (17.3) all recorded appropriate values when compared with WHO standard. The acidity of the soil using pH value as an indicator showed that the uncontaminated control soil samples were acceptable for crops also the Ec values. The heavy metals analysed indicates that the control soil samples were also moderate in heavy metals accumulation when compared with the contaminated soil samples particularly Cd, Pb (0.08) and Hg (0.01) while Cd was not detectable. These findings have shown that automobile activities can denature soil properties which could lead to soil infertility. The automobile activities has to be controled by the concerned agencies in Nigeria. Environmental education should be encouraged to reduce effects of anthropogenic activities on soil quality in the study area.
Evaluation of the Perception and Adoption of Environmental Management System in Small and Medium Enterprises in the Manufacturing Sector in Lagos and Ogun States, Southwestern Nigeria
Authors: Amiolemen S. O. , Adenekan O. , Ologeh I. , Omoyajowo K. , Oludoye O. , Raimi M.
Published: September 2024

The objective of this paper was to evaluate the perception and adoption of environmental management system in small and medium enterprises in the manufacturing sector in Lagos and Ogun States, Southwestern Nigeria using appropriate standard techniques. The paper posits that environmental management literacy and advocacy should be carried out in SMEs. Environmental management practices involve engaging both industries and product end-users in sustainable practices. The paper concludes that the implementation of environmental management practices and culture by SMEs will abate environmental pollution and its concomitant health risks to humans, the environment, flora, and fauna. Mandatory and voluntary environmental measures 3 are suggested as a means of engendering eco-friendly innovation for sustainable development, triggering employment, job security, and gross domestic product.
Effects of Caffeine on Cardiovascular Toxicity in Adult Wistar Rats
Authors: Onyeije B. P. , Innih S. O.
Published: September 2024

Caffeine has been used for thousands of years. When taken in excess, caffeine can have negative effects on the body's overall health, including the cardiovascular system. Hence, the objective of this study was to evaluate the impact of caffeine on the cardiovascular toxicity in adult Wistar rat's using histological techniques. Twenty rats were randomly divided into four groups. Group A was the normal control group (no caffeine administration). Groups B, C and D were the caffeine intoxicated groups treated with 200, 400, and 800mg/kg body weight of caffeine. Animals in groups B-D received daily oral administration of caffeine for thirty days. The study's findings demonstrated that caffeine is a somewhat cardio-toxic substance that altered the structure of the Wistar rats' hearts in a dose-dependent manner. Caffeine administration at varying levels resulted in the heart muscle exhibiting distinct separation of neighboring muscle fibers, vascular distortion, and myocardial degeneration accompanied by vascular congestion in all caffeine-treated groups. The group that received greater dosages of caffeine showed more severe insults, indicating that the effects of caffeine were dose-dependent. The data obtained from this study suggests that caffeine induces cardio-toxicity in ascending manner of dose dependent pattern in adult Wistar rats.