bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficiency Improvement of Friction Stir Welding Parameters on AZ91 Magnesium Alloy Joints
Authors: Fernandez Dr. A. Antony , Boopathiraja R. M. , Suriyaprakash L.
Published: February 2024

Abstract: Friction Stir Welding (FSW) is a solid-state welding that permits an intensive formof parts and geometries to be welded with great nature of joints. The use of high-quality Magnesium alloys is extending in shipbuilding industry, particularly for the advancementof naval warships, cruise ships, littoral surface craft and merchant ships. FSW advancementhas been seemed to have various focal points for the exploitation of Magnesium alloys structures, as it is a minimal effort welding process. The objective is to come across the optimum levels of the process parameters in which it yields maximum tensile strength andbetter hardness. A three-factor, three-level design is utilized for optimizing the FSW process parameters and a Taguchi L9 orthogonal array experimental set up is used to anticipate the responses. The system parameters considered are Rotational speed, Transverse speed and the Tool tilt angle. The Friction stir welding is processed for butt joining of Magnesium alloys (AZ91) plates with 6 mm thickness. Tensile testing is attempted on dog-bone kind test specimen for Magnesium alloys. Analysis of Variance (ANOVA) has been used to analyze the effect of different parameters regarding the responses. The microstructural attributes of the welded segments, including base metal, heat affected zone (HAZ), Thermo Mechanically Affected Zone (TMAZ) and Stir Zone (SZ) are examined through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis carried out to quantify the chemical element allocation at the weld interface. The observed optimum condition for Magnesium alloys (AZ91) is 560 rpm, 60 mm/min and 1 degree.
Chemical composition of seaweed and its medical-biological properties
Authors: Gorbachev Anatoly L. , Kubasov Roman V.
Published: February 2024

RELEVANCE. Seaweed, along with all the other aquatic biological resources, is of great economic importance for all countries of the world community. Due to positive effects of biologically active substances, contained therein, it is widely used as dietary supplements, drugs, hydrocolloids (agar, alginates, carrageenan).
OBJECTIVE. Based on literature data to study current knowledge about the chemical composition of seaweed and its medical-biological properties, which can be used in life activity.
MATERIALS AND METHODS. The study used literature sources from international databases Web of Science, Scopus as well as the national library system eLibrary. The keywords in the search engine: seaweed, biochemical composition, biologically active properties, medical importance.
RESULTS. The chemical composition of seaweed is due to its habitat. It contains practically all chemical elements, present in seawater. Because of beneficial biological effects, seaweed is widely used by humans, especially in medicine. Among organic compounds seaweed is rich in polysaccharides, lipids, protein compounds as well as vitamins. The main part of polysaccharides belongs to alginic acid and fucoidan. Alginates have anti-inflammatory, sorption and reparative properties, normalize metabolism. Fucoidans have anticoagulant and antioxidant effect, inhibit penetration of viruses into tissue cells.
DISCUSSION. Seaweed is rich in protein compounds. It contains all essential amino acids. Moreover, all classes of fatty acid (especially polyunsaturated) are found in seaweed. Lastly, many water-soluble and fat-soluble vitamins are synthesized in seaweed, like plants on land: ascorbic acid, tocopherols, carotenes, thiamine, cobalamins, etc.
It is concluded that seaweed can be considered a unique supplier of biologically active components: minerals, proteins, polysaccharides, polyunsaturated fats and vitamins. Its use is justified with therapeutic and preventive purposes.
Modern diagnostic approaches to osteoarticular manifestations in Navy diving personnel: retrospective study
Authors: Krukov Evgeniy V. , Kireeva Elena B. , Chumakov Aleksandr V. , Cherkashin Dmitry V. , Yazenok Arkadiy V. , Makiev Ruslan G. , Agafonov Pavel V.
Published: February 2024

OBJECTIVE. Study the features of the pathogenesis and clinical picture of musculoskeletal disorders in different categories of the Navy military personnel and pensioners of the Defense Ministry (DM) based on a set of clinical, instrumental, laboratory and genetic examination methods.

MATERIALS AND METHODS. There was screening and study of medical records of 98 Navy military personnel and pensioners of DM in the following groups: I — the Navy military personnel with no hyperbaric exposure in the anamnesis, II — military personnel, belonging to deep water divers with moderate experience (total work experience in hyperbaric conditions: 20–500 hours), III — military personnel, belonging to deep water divers with considerable experience (total work experience in hyperbaric conditions: 700–2500 hours), IV — pensioners of DM, whose professional activities were related to operations on extreme depth (aquanauts), V — pensioners of DM with no hyperbaric exposure in the anamnesis. There was a detailed laboratory and instrumental examination of bone metabolism, including digital radiography, osteodensitometry, MRI, CT and genetic testing.

RESULTS. The Navy diving personnel experience significant osteoarticular manifestations by type of dysbaric osteonecrosis, most pronounced in pensioners of DM – aquanauts.

DISCUSSION. Digital radiography and MRI are found to be an optimal diagnostic method of dysbaric osteonecrosis and “dysbarogenic osteoarthropathy”. As a method of express diagnostics, it is advisable to use innovative urine test strips to determine threshold concentrations of β-crosslaps and α-crosslaps markers of bone resorption.
Clinical blood test interpretation. Part 1. Neutrophil granulocytes
Authors: Bazarnyi Vladimir V. , Sosnin Dmitry Yu.
Published: February 2024

INRODUCTION. Recent decades are characterized by a rapid introduction of modern automated analytical systems in clinical laboratory diagnostics such as hematology analyzers, which provide a high accuracy of results as well as additional (compared to routine tests) and often more valuable information. Automated blood test has made urgent the problem of interpreting both new tests and “routine” parameters that is relevant to any section of clinical medicine. Therefore, this lecture is aimed at doctors of different specialties.
OBJECTIVE. Interpret a clinical blood test.
DISCUSSION. It is hard to review all aspects of hematological analysis within the scope of one lecture, thus part 1 will investigate one of leukocyte populations – neutrophil granulocytes, which include stab and segmented neutrophils. The lecture presents well-known data about neutrophilic leukocytosis and neutropenia. The emphasis is placed on new parameters of automated blood test – IG (immature granulocytes), Neut-RI (reactivity index), Neut-GI (granularity index), MNV (the average volume of neutrophil), structurally dispersed characteristics (NE-WX, NE-SFL, NE-WZ) and some others. Along with modern parameters it was noted the importance of the traditional cytological examination of blood smear, enabling to detect anomalies of neutrophil (degenerative-dystrophic changes of cytoplasm, apoptosis, nucleus pathology).
Overall, recent years have shown a significant improvement in laboratory diagnostic capabilities of reactive changes (with inflammation, injury, etc.) and blood diseases (anemia, myelodysplastic syndromes, hemoblastosis, etc.), based on accumulated knowledge in the field of laboratory hematology, including clinical significance in evaluating neutrophils.
Quantitative relations between different measurement contexts
Authors: Ji Ming , Hofmann Holger F.
Published: February 2024

In quantum theory, a measurement context is defined by an orthogonal basis in a Hilbert space, where each basis vector represents a specific measurement outcome. The precise quantitative relation between two different measurement contexts can thus be characterized by the inner products of nonorthogonal states in that Hilbert space. Here, we use measurement outcomes that are shared by different contexts to derive specific quantitative relations between the inner products of the Hilbert space vectors that represent the different contexts. It is shown that the probabilities that describe the paradoxes of quantum contextuality can be derived from a very small number of inner products, revealing details of the fundamental relations between measurement contexts that go beyond a basic violation of noncontextual limits. The application of our analysis to a product space of two systems reveals that the nonlocality of quantum entanglement can be traced back to a local inner product representing the relation between measurement contexts in only one system. Our results thus indicate that the essential nonclassical features of quantum mechanics can be traced back to the fundamental difference between quantum superpositions and classical alternatives.
Informalidad económica en América Latina
Authors: Ramos Zaga Fernando Antonio
Published: February 2024

La economía informal (EI), dinámica y omnipresente, genera verdaderos obstáculos para el desarrollo de la sociedad. Según la OIT (2018), más del 60% a mitad de la población activa forma parte de este sector económico no registrados. En ese sentido, el propósito de este artículo es analizar el fenómeno de la informalidad, reconocer las tendencias emergentes y profundizar nuestra comprensión de sus causas, impactos y posibles soluciones. Se realizó una revisión de literatura sobre la EI. Se utilizaron investigaciones provenientes de bases de datos académicas y gubernamentales, que contribuyeron a la investigación. Los hallazgos muestran que los efectos de la EI se traducen en bajos ingresos, acceso limitado a servicios públicos esenciales y evasión tributaria. Se concluye que el abordar la complejidad de las EI requiere un enfoque que incluya una colaboración multidisciplinaria con la finalidad de cambiar actitudes y comportamientos y actitudes respecto a la tributación, cuyos posibles resultados positivos incluyen un mayor cumplimiento de las obligaciones tributarias, la reducción de los niveles de informalidad y una base sólida para un crecimiento económico duradero.
Motivación sobre las materias de gestión empresarial en titulaciones interdisciplinares
Authors: Jimenez Jimenez Maria del Amor , Gessa Perera Ana , Sancha Dionisio Pilar
Published: February 2024

La implantación de planes de estudios interdisciplinares, conjuntos o dobles titulaciones en grados universitarios es cada vez mayor, generando la necesidad de analizar si las materias pertenecientes a áreas, o disciplinas específicas, pueden afectar negativamente a la motivación del alumnado sobre la titulación. Por ello, consideramos de gran interés reflexionar sobre la percepción de este tipo de titulaciones por parte del alumnado. Nos centramos en analizar la motivación de los estudiantes del Grado de Gestión Cultural frente a las materias de la vertiente empresarial del título. Para el estudio se ha utilizado el Cuestionario de Estrategias de Aprendizaje y Motivación (CEAM II) y se han aplicado pruebas estadísticas para estudiar los comportamientos de las diferentes dimensiones e ítems motivacionales considerando, además, el efecto que la variable curso pueda causar en la motivación del alumnado. Los resultados revelan bajos niveles de ansiedad y una adecuada adaptación del alumnado a las materias de la vertiente empresarial de la titulación. Resulta relevante la importancia atribuida al valor de la tarea y las repercusiones que esta dimensión tiene sobre otras subescalas motivacionales. Este trabajo es una aportación necesaria para cubrir la evidencia empírica de este campo de investigación.
Stimulating creative thinking in students with simple experiments on Einstein's equivalence principle in primary and secondary education
Authors: Krulj Ivana , Nesic Ljubisa , Slisko Josip , Zivkovic Biljana
Published: February 2024

The same instructional units on Gravity and Weightlessness were approached in
two different ways: through a traditional method that doesn't rely solely on
teacherled lectures but combines various established teaching techniques,
and through the novel Predict-Observe-Explain approach, incorporating the
implementation of two new experiments designed to enhance physics education.
This pilot study aimed to assess the stimulation of students' creative
thinking, specifically in the 7th grade of primary school and the 1st grade
of high school. The results indicated that students who engaged with the
innovative teaching approach demonstrated a higher level of creativity.
Physical and metaphysical implications of a probabilistic interactionist account of mental causation
Authors: Dimitrijevic Dejan
Published: February 2024

The strongest support to the metaphysical thesis of physicalism - the
argument from the causal closure of the physical - is shown to be effective
only against the accounts of mental causation manifested in the action of
forces. An interactionist account of mental causation based on probabilistic
considerations of anomalous correlations of neural events, instead of
anomalous accelerations of the particles that make up the nervous system, is
proposed. Local violation of the Second Law of thermodynamics by the actions
of the mind is implied, and mental causation is explained as the disposition
of mental states to alter the state probability distribution within the
nervous system, with no violation of the conservation laws. The main
features of this account and some of its physical and metaphysical
implications and advantages are discussed: an indication of the causal unity
of nature, elimination of the problem of causal power drainage, explanatory
simplicity, and redefining the domain of the physical. The account refutes
the claim of the anomalousness of the mental and anticipates the existence
of probabilistic psychophysical laws. Its truthfulness is verifiable by
extensive neurophysical and physiological research, involving statistical
analysis of neural correlations.
A new fracability evaluation model for complex lithologies fractured shale oil reservoir
Authors: Zhang Ran , Lv Cheng-Jun , Ren Qian-Kun , Wang Yang , Liao Yang , Zhang Zishan
Published: February 2024

Manufacturing knowledge can be preserved through knowledge accumulation and continuous integration. In order to improve the using efficiency of manufacturing knowledge, this knowledge is stored and used in the way of Knowledge graph. This paper will study the construction of Knowledge graph based on manufacturing process methods and the ability of Knowledge graph to provide services. This kind of manufacturing knowledge capability not only provides the manufacturing realization method of processing technology, but also can correspond to the design realization method of design graphics, providing theoretical support for the integrated realization of design and manufacturing process.
Numerical simulation study on factors affecting the pre-CO2 fracturing effect in shale oil reservoirs: A case study on Kong-2 member in Cangdong Sag, China
Authors: Song Shun-Yao , Liu Xue-Wei , Fu Yong-Qiang , Zang Yu-Xi , Wang Hai-Zhu , Tian Fu-Chun , Shao Li-Fei , Jia Yun-Peng , Zhao Tao , Yin Qi-Wu
Published: February 2024

A novel procedure has emerged in recent years within oilfields ? namely, the utilization of a hybrid fracturing method employing pre-CO2 injection along with sand-carry slick water. In this paper, based on the real logging data of shale oil reservoirs in the second member of Cangdong Sag, Huanghua Depression, combined with the GOHFER, a coupled 3-D hydraulic fracture propagation model is proposed. This research delves into an examination of how engineering factors exert their influence on the process of fracture propagation. The quantitative analysis is conducted encompassing critical fracture parameters such as half-length, height, and width, and self-defined fracture seepage area and fracture front fractal dimension. The research findings indicate that as injection displacement increases, the fracture shape undergoes a transformation from being ?long, low, and wide? to becoming ?short, high, and narrow?.
Pre-treatment influence of liquid nitrogen and microwave on the mode I fracture characteristics of granite
Authors: Su Shanjie , Zhou Chunbo , Wang Shengcheng , Cai Feng , Jiang Xuan
Published: February 2024

Microwave and liquid nitrogen have shown great potential applications in the mining, geological, petroleum, and particularly metal mining fields. In order to further promote their application in rock tunneling engineering, this paper conducted a series of I-model fracture tests on hard rock (granite) to explore the impact of liquid nitrogen, microwave, and liquid nitrogen and microwave pretreatment on the fracture characteristics of hard rock. The results showed that compared with the control group, all pretreatment groups had varying degrees of reduction in wave speed and fracture toughness, especially the microwave and liquid nitrogen group.
Numerical simulation of a failure pattern of the roof in coal seam working face
Authors: Zhang Xiu-Feng , Zhang Ning , Li Xiang , Liu Chuan-Cheng , Chen Yang
Published: February 2024

This study adopts the cohesive element technology for the first time to
analyze the dynamic evolution process of crack formation and propagation,
and to clarify the mechanical mechanism of the "O-X" failure pattern in the
roof. The mechanical behavior of cohesive failure inside the rock is
simulated based on the maximum nominal stress criterion, and the
Benzeggagh-Kenane (BK) fracture criterion is used to further describe the
dependence of fracture energy on the combination of mixed tensile-shear
mode. The results show that the "O"-shaped crack is formed on the top
surface of the roof, and delamination occurs along the thickness direction,
which coincides with the crack bifurcation position on the bottom surface of
the roof. The "cross"-shaped crack forms on the center of the bottom surface
of the roof, and extends towards the four corners at the bifurcation
position to form a spatial "X"-shaped crack.
Heat transfer enhancement of staggered water-droplet grooved microchannel heat sink using Al2O3 nanofluid
Authors: Soo Yan , Yu Kok , Ismail Mohd
Published: February 2024

The performance reliability and durability of modern cutting-edge technology are highly dependent on the ability of the devices to dissipate enormous amounts of heat to the ambient environment. A synergetic combination of two passive heat transfer enhancement techniques would be favourable to prevent overheating. The concurrent implementation of Al2O3 nanofluid and staggered water-droplet groove geometries in micro-channel heat sink application was investigated using numerical approach. Numerical results reported in this study revealed that the heat dissipation capability of the micro-channel heat sink can be improved when Al2O3 nanofluid is used in conjunction with the water-droplet grooves arranged in staggered manner. The predictive accuracy of the numerical method has been validated with published results available.
Experimental study on post-fracture oil-water displacement mechanism of tight sandstone reservoir with nuclear magnetic resonance
Authors: Zhao Jinsheng , Ouyang Wen , Hui Bo , Yang Qigui , Ju Yingjun
Published: February 2024

In this paper, three different fracturing fluids are used as replacement working fluids, and nuclear magnetic resonance technology is used to study the oil-water replacement law of tight sandstone cores in the field, revealing the main influencing factors of oil-water replacement in the process of tight oil fracturing flow back.
Fracture initiation and propagation behaviors of thinly interbedded tight sandstone reservoirs by various hydraulic fracturing methods
Authors: Chen Yong , Xia Zhihao , Lan Tian
Published: February 2024

This paper proposed three new fracturing methods, slick water with an integrated variable viscosity fracturing, supercritical CO2 shock fracturing and pulse hydraulic fracturing. To verify the efficacy of the new methods, we conducted laboratory true-triaxial fracturing experiments by using outcrops collected from the Lower Shihezi formation, Ordos Basin. The results indicate that supercritical CO2 shock fracturing is observed to have the lowest breakdown pressure compared with other methods.
Experimental study on collaborative enhancement of led heat dissipation characteristics by pulsating heat pipe and heat pipe
Authors: Shang Fumin , Ju HaiJiao , Liu Chaoyue , Yan Tianhai , Cao Xin , Liu Dong , Liu Jianhong
Published: February 2024

The objective of this research is to experimentally evaluate the specific impact of a collaborative heat sink composed of gravity heat pipes (GHP) and pulsating heat pipes (PHP) on the thermal efficiency of LED light sources. The heat sink developed in this experiment is designed to improve the thermal management system, ensuring that LED operate within a safe temperature range, which is crucial as the performance of LED is directly affected by their junction temperature. An HP-PHP collaborative heat sink was employed in the experiment, where PHP served as heat dissipating fins to enhance its thermal performance, while HP handles the majority of the heat transfer tasks. The results showed that under forced convection conditions, the HP-PHP collaborative heat sink can increase the maximum thermal power capacity of LED to 192 W. The HP-PHP collaborative heat sink can reduce the substrate?s temperature to below 70.5 ?C in passive mode when the LED input power does not exceed 96 W. Additional experimental results show that the minimum thermal resistance of the collaborative heat sink is 0.19 K/W under natural-convection conditions, under forced convection conditions, this value drops to 0.15 K/W, which still lower than the non-collaborative heat sink. These results demonstrate that the contact thermal resistance between HP and PHP significantly enhances the thermal performance of the collaborative heat sink. Therefore, this collaborative type of heat sink is an effective method for cooling high power LED.
Study of the leakage tracer gas transport property in condenser: Hellium and Sulfur-Hexafluoride
Authors: Wan Jianfeng , Hu Jian , Bi Wenyan , Yu Menglin , Xu Xiangxuan , Sun Yihong , Zhou Qiang , Hou Yikai , Guan Xuemao
Published: February 2024

Helium (He) tracer method is one of the common methods used to detect tube bundle leakage in the condenser. To improve the detection accuracy, sulfur hexafluoride (SF6) is considered a tracer gas instead of He. This paper combines the N-S equation, porous medium model, flow diffusion model and steam heat transfer model to develop the numerical model of tube bundle leakage in the condenser. The simulation results show that the transport of leaked gases (He and SF6) consists of flow and diffusion patterns. The existence of the diffusion process is confirmed further through theoretical analysis. The two gases have the same transport behavior in the pure flow process. When it involves the diffusion process, the flow rate of He is 6.67 times that of SF6. In other words, the time required for He to reach the same concentration difference is 1/6.67 times that of SF6. In addition, the influence of leakage intensity and gas species on the transport is analyzed. The study results provide a theoretical basis for SF6 to replace He as a tracer gas to detect tube bundle leakage.
Exploring thermal response in aluminum heat sinks with variable surface roughness for enhanced cooling
Authors: Balakrishnan Rajasekaran , Govindaraj Kumaresan , Mahalingam Arulprakasajothi , Nagappan Beemkumar
Published: February 2024

The shrinking size and increasing power consumption of electronic products also make their thermal management challenging. Poor thermal management results in increased temperature of the electronic component, ultimately leading to the failure of the element. Thermal management of electronic devices is assisted by-passive techniques such as heat sinks. Phase change material-filled heat sinks attract industries, as they are compact and do not require frequent maintenance. In this study, heat sinks with internal surface modifications, i.e., engraving and grit blasting, are developed. The heat sinks are provided with heat storage mediums like paraffin wax and nanoparticles to analyse their effect on thermal management. This study employed two different nanoparticles, i.e., silver titanium dioxide and graphene. A simple heat sink without surface modification and a heat storage medium was used as a reference. It was found that using graphene-mixed PCM in the smooth heat sink increased the charging time by about 8%. Adding graphene nanoparticles to the phase change material decreases the discharging time by about 29%. Grit-blasted heat sinks took the most time to discharge, followed by base-engraved heat sinks. This is because the internal surface roughened heat sinks stored more heat energy during the charging process. Adding graphene nanoparticles to the PCM increases the duty cycle by about 40%. When used with paraffin wax, base engraved heatsinks and grit-blasted heat sinks have increased the duty cycle by 11% and 36%, respectively.
The impact of water injection-induced fractures on residual oil distribution in tight sandstone reservoirs
Authors: Sun Xinhua , Dang Hailong , Shi Mingliang , Liu Wenqiang , Kang Shengsong , Wang Qiang , Ao Yangyang , Zhao Fengnian
Published: February 2024

This study conducted water-induced fracture experiments and full-diameter core displacement experiments on the cores of a certain oil reservoir in the Ordos Basin, aiming to investigate the impact of these induced fractures of different sizes on displacement efficiency and the distribution of remaining oil, and to perform quantitative analysis. The experimental results indicate that the oil displacement efficiency of the core is related to the depth, angle, and complexity of full-diameter core fractures.
The function of nano layer in enhancing the thermal conductivity of TiO2/water nanofluids
Authors: Huang Xiaoyan , Zhang Xiaohui , Qing Shan
Published: February 2024

Nanoparticles have the capability to effectively improve the thermal
conductivity of base fluids, thus improving the heat transfer coefficient of
heat transfer systems. In this study, a non-equilibrium molecular dynamics
(NEMD) method based on the Fourier law is employed to study the thermal
conductivity of TiO2 (r-TiO2)/water nanofluids with temperatures ranging
between303K and 333K and volume fractions in the range of1-2%. The ordered
layer structure as a shell is analyzed and its influence is surveyed by
calculating the number density and radial distribution function (RDF).The
results revealed that a clear, solid-like nanolayer of about 0.5 nm can be
observed around the nanoparticle. In this regard, the thickness of the
nanolayer is less affected by variations in volume fraction and temperature.
The g(r) values and the number density decreased with the increase
in temperature. Additionally, the g(r) values and the number density at the level
of the nanolayer were much higher compared to those at other parts. This
indicates the existence of more water molecules in the nanolayer, thereby
reducing contact thermal resistance and improving thermal conductivity.
Macroscopically, the thermal conductivity increases with the increase
in volume fraction. It was found that the increase in the volume fraction from
1%to 2%at303Kresulted in an increase in the effective thermal conductivity
from1.027 and 1.042, respectively. In other words, the thermal conductivity
of the nanofluid was 2.7% and 4.2% higher than that of the base liquid under
the same conditions.
Revisiting distance metrics in k-nearest neighbors algorithms: Implications for sovereign country credit rating assessments
Authors: Cetin Ali , Buyuklu Ali
Published: February 2024

The k-nearest neighbors (k-NN) algorithm, a fundamental machine learning technique, typically employs the Euclidean distance metric for proximity-based data classification. This research focuses on the feature importance infused k-NN model, an advanced form of k-NN. Diverging from traditional algorithm uniform weighted Euclidean distance, feature importance infused k-NN introduces a specialized distance weighting system. This system emphasizes critical features while reducing the impact of lesser ones, thereby enhancing classification accuracy. Empirical studies indicate a 1.7% average accuracy improvement with proposed model over conventional model, attributed to its effective handling of feature importance in distance calculations. Notably, a significant positive correlation was observed between the disparity in feature importance levels and the model's accuracy, highlighting proposed model?s proficiency in handling variables with limited explanatory power. These findings suggest proposed model?s potential and open avenues for future research, particularly in refining its feature importance weighting mechanism, broadening dataset applicability, and examining its compatibility with different distance metrics.
The impact of project-based learning in physics education on university students’ motivation to learn and metacognition
Authors: Cavic Milan , Beljin-Cavic Milica , Horvat Sasa , Bogdanovic Ivana , Stanisavljevic Jelena
Published: February 2024

Project-based learning, involving an interdisciplinary approach, can be
applied in the treatment of the content of various teaching subjects. It is
also applicable at the university level. The aim of this research was to
examine whether project-based learning could enhance students? motivation to
learn physics and their metacognitive awareness. Therefore, a pedagogical
experiment with one group was applied. The sample consisted of 94 first-year
students from the Faculty of Sciences and the Faculty of Technology at the
University of Novi Sad. A pedagogical experiment was applied, and
statistical analysis of the collected data was conducted. Project-based
learning was implemented in addressing the topic of Diffusion and Osmosis,
which involves the integration of content from biology, physics, and
chemistry. Students created eighteen projects, and their products were video
materials. The data collection technique was the use of a questionnaire. The
research results showed that there was no significant difference in
students? motivation before and after the implementation of project-based
learning. However, a statistically significant difference was found in
students? metacognition before and after the application of project-based
learning. The results of this research suggest the need to encourage the
implementation of project-based learning in university education with the
aim of increasing students? metacognitive awareness and further enhancing
the implementation of project-based learning to positively impact students?
motivation for learning.
Relative aerobic load of walking in people with multiple sclerosis
Authors: Gravesteijn Arianne S. , Timmermans Sjoerd T. , Aarts Jip , Hulst Hanneke E. , De Jong Brigit A. , Beckerman Heleen , De Groot Vincent
Published: February 2024

Objective: To examine the energy demand of walking relative to aerobic capacity in people with multiple sclerosis.
Design: Cross-sectional cohort study.
Patients: A total of 45 people with multiple sclerosis (32 females), median disease duration 15 years (interquartile range (IQR) 9; 20), median Expanded Disability Status Scale 4 (min–max range: 2.0; 6.0).
Methods: Aerobic capacity, derived from a cardiopulmonary exercise test and gas exchange measurements, assessed during a 6-min overground walk test at comfortable speed, were analysed. The relative aerobic load of walking was determined as the energy demand of walking relative to oxygen uptake at peak and at the first ventilatory threshold. Healthy reference data were used for clinical inference.
Results: People with multiple sclerosis walk at a mean relative aerobic load of 60.0% (standard deviation 12.8%) relative to peak aerobic capacity, and 89.1% (standard deviation 19.9%) relative to the first ventilatory threshold. Fourteen participants walked above the first ventilatory threshold (31%). Peak aerobic capacity was reduced in 45% of participants, and energy demands were increased in 52% of participants.
Conclusion: People with multiple sclerosis walk at a relative aerobic load close to their first ventilatory threshold. A high relative aerobic load can guide clinicians to improve aerobic capacity or reduce the energy demands of walking.
Paraneoplastic neurological syndrome associated with onconeural autoantibodies: report of two cases
Authors: Kalmoukos Panagiotis , Kouparani Christina , Moscha Nikoletta , Kouroupis Dimitrios , Giza Evangelia , Sapouridis Georgios , Simoulidou Elisavet , Varouktsi Anna , Chatzimichailidou Sofia , Petidis Konstantinos , Pyrpasopoulou Athina
Published: February 2024

Paraneoplastic neurological syndromes (PNS) are rare and often severe neurological complications of malignancies, significantly impacting patient prognosis and quality of life. They are characterized by a diverse range of onconeural autoantibodies, with further discoveries likely due to ongoing research. Among these, high-risk autoantibodies primarily target intracellular neural cell antigens. We present cases of lung cancer patients who developed limbic encephalitis and seizures at diagnosis, suggestive of PNS. Each case demonstrated distinct autoantibody profiles. Recognition of these potentially life-altering neurological sequelae, as paraneoplastic manifestations of malignancies, is crucial for physicians. PNS may precede primary cancer diagnosis and substantially affect patient presentation and overall outcome. We provide in detail the diagnostic work-up and available treatment options for these complex cases.
Development of colistin resistance via heteroresistance modeling in Klebsiella pneumoniae: A diagnostic study
Authors: Seo Jungyu , Ko Kwan Soo
Published: February 2024

Purpose: Colistin heteroresistance mediates the failure of antibiotic treatments, is prone to lead to colistin resistance, and has been frequently reported in Klebsiella pneumoniae. This study investigated origins of the increase in colistin resistance following colistin exposure to colistin-heteroresistant K. pneumoniae.Methods: A modeled colistin-heteroresistant K. pneumoniae strain (i.e., mimicking colistin- heteroresistant [m-CLHR]) was generated using a susceptible K. pneumoniae strain ATCC 10031 and its resistance-induced mutant. Heteroresistance patterns were investigated through population analysis profiling (PAP), competition assays, and fluctuation and stability tests. An in vitro time-killing assay for colistin was performed for the m-CLHR to identify the change in susceptible and resistant populations before and after colistin exposure.Results: The generated m-CLHR strain showed a typical heteroresistance pattern for colistin in PAP, and its competition assay did not show fitness costs for any population. The ratio of resistant cells to susceptible cells did not deviate significantly from the range of heteroresistance in the fluctuation test, while the ratios of resistant cells preserved their stability. The in vitro time-killing assay thus showed that the resistant cells increased upon colistin exposure; sequencing analyses confirmed that the surviving resistant cells did not originate from susceptible cells by mutation. This study successfully modeled a colistin-heteroresistant K. pneumoniae strain, i.e., m-CLHR.Conclusion: In this modeled heteroresistant strain, only the colistin-resistant population survived the colistin treatment—this suggests that the development of colistin resistance from heteroresistant strain is because of the selection of a resistant population and not by the induction of resistance through mutations in susceptible populations.
Revisión sistemática de las zoonosis en animales domésticos y de producción documentadas en el Estado de México
Authors: Flores Ortega Ariadna , Bautista Gómez Linda Guiliana
Published: February 2024

Las enfermedades infecciosas zoonóticas (o zoonosis) representan graves riesgos para la salud tanto de los animales como de los humanos, lo cual puede tener impactos económicos a nivel mundial. Por eso, esta revisión tuvo el objetivo de recopilar información para analizar sistemáticamente diversas investigaciones sobre el estudio de las zoonosis presentes en animales domésticos y de producción documentadas en el Estado de México con el fin de obtener herramientas que ayuden a prevenir enfermedades que causan problemas de salud pública. Para ello, se utilizó el método Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), aplicando diversos buscadores científicos como Google Scholar, PubMed y Scielo. La revisión se limitó hasta el 6 de noviembre de 2022. Como resultado se obtuvieron 161 artículos: 148 provenientes de Pubmed, 9 de Scielo y 4 de Google Scholar. Del total de artículos encontrados 80 fueron eliminados tras leer el título, ya que tenían correspondencia con la mayoría de las palabras clave. Posteriormente, 77 artículos fueron eliminados, ya que, al leer el resumen, se trataba de artículos de revisión o no contaban con las características solicitadas. Los artículos seleccionados para evaluar la elegibilidad fueron 6; sin embargo, se descartaron 2 debido a que fueron realizados en México, pero no eran específicos del Estado de México, y tenían más de 5 años de antigüedad. Finalmente, solo 4 artículos fueron incluidos para esta revisión sistemática.
Farklı Biyopolimerler ile Kaplanmış Ağartılmamış Kraft Kâğıtlarının Mekanik ve Fiziksel Özellikleri
Authors: ONDARAL Meryem , ERSOY KALYONCU Evren
Published: February 2024

Plastik film kaplamalar uzun yıllardır ambalaj malzemesi üretiminde kullanılmaktadır. Gıda ambalajlarında kullanılan malzemenin insan sağlığına zarar verebilecek kimyasallar içermemesine dikkat edilmelidir. Bu çalışmada, ağartılmamış kraft test kağıtları, plastikleştirici olarak gliserol katkısı ile hazırlanan jelatin ve sodyum aljinat bazlı biyopolimerik çözeltiler ile kaplanmıştır. Hazırlanan dispersiyon çözeltilerinin kağıtlara uygulanması için sürme yöntemi kullanılmıştır. Mekanik özellikler olarak çekme, yırtılma, patlama indisleri ve fiziksel özellikler olarak COBB, hava geçirgenlik testleri belirlenmiştir. Hem jelatin hem de sodyum aljinat kaplama ile üretilen kağıtların tüm mekanik özellikleri iyileştirilmiştir. Kontrol kağıtlarına göre jelatin kaplı kâğıtların su itici özelliğinin arttığı, sodyum aljinat kaplı kağıtların ise su absorblama özelliğinin arttığı gözlenmiştir. Jelatin kaplı kağıtların kontrol örneklerine göre hava geçirgenliği azalırken, sodyum aljinat kaplı kağıtların ise hava geçirgenliğinin hiç olmadığı belirlenmiştir. Yapılan çalışma sonucunda ambalaj kağıtları için istenilen mekanik ve fiziksel özellikleri iyileştirilmiştir.
Analysis of Essential Oil from Calendula arvensis L. (Field Marigold Flowers)
Authors: OKAN Onur Tolga
Published: February 2024

In this study, the quantity, structure, and classification of the essential oil obtained from the flowers of Field-grown Marigold (Calendula arvensis L.) individuals grown in the field environment in Maçka District, Trabzon Province, are presented. The essential oil of the collected and dried flowers was obtained using the Clevenger apparatus through the water distillation method. The components of the essential oil extracted from flowers were determined qualitatively using GC-MS/FID (Gas Chromatography-Mass Spectrometry/Flame Ionization Detector). The components that constitute 99.15% of the essential oil of field-grown Marigold have been identified. According to the results obtained, 74 known components were identified in the extracted essential oil from flowers, while only 2 components remained unidentified. The primary components of essential oil have been identified as %26.34 τ-kadinol, %10.99 δ-kadinol, %16.28 δ-kadinen, %8.79 α-thujen, and %6.04 α-pinen, respectively, in the order of their highest concentration. When considering the chemical classification of components identified in the flowers of Calendula arvensis L, sesquiterpenoids were found to be present at the highest proportion, amounting to 42.48%. When terpenes, terpenoids, or their derivatives were evaluated as components, it was found that they constituted 53 compounds and were present at an extremely high level of 93.32% in the essential oil of Calendula arvensis L.
Akdeniz ve İran-Anadolu Sıcak Noktalarının İç İçe Geçtiği Besni (Adıyaman-Türkiye) İlçesinde Tehlike Altındaki Taksonlar
Authors: Özcan Şener
Published: February 2024

Bu araştırmada, Akdeniz Havzasında, Akdeniz ve İran-Anadolu sıcak noktalarının kesiştiği sahada bulunan Adıyaman iline bağlı Besni ilçesinde doğal yayılış gösteren taksonların IUCN (Uluslararası Doğa Koruma Birliği) kırmızı liste kategorileri literatür taraması yapılarak araştırıldı. Sonuç olarak, IUCN kriterlerine göre, 58 familyanın 121 cinsine ait toplam 162 taksonun tehlike kategorisi belirlendi. Bu taksonların 73’ü (%45) endemik, 14’ü (%9) nadir bulunan, 75’i (%46) ise geniş yayılışlı bitkilerdir. Bu taksonların fitocoğrafik bölgelere göre dağılımı şöyledir: İran-Turan 71 (%43,8), Akdeniz 13 (%8), Doğu Akdeniz 13 (%8), Avrupa-Sibirya 6 (%3,7) ve bilinmeyen veya geniş yayılışlı 59 (%36,5)’dur. IUCN kriterlerine göre; 7 (%4,3) CR (çok tehlikede), 6 (%3,7) EN (tehlikede), 21 (%13) VU (zarar görebilir), 17 (%10,5) NT (tehdit altına girebilir), 104 (%64,2) LC (en az endişe verici) ve 7 (%4,3) DD (yetersiz veri) kategorisinde takson bulunmaktadır. Bu taksonlardan 34 takson (%20.98) yok olma tehlikesi altındadır. Araştırma alanında yapılan inclemelerde taksonlar üzerine risk faktörlerinin büyük oranda antropojenik kaynaklı olduğu gözlemlenmiştir. Aşırı otlatma, aşırı toplama, yol yapımı, tarla/bahçe açma, kentleşme, ormansızlaştırma, doğal habitatların mesire alanına dönüştürülmesi, bataklık alanların kurutulması ve çevre kirliliği türler ve habitatlar üzerinde gözlenen risk faktörleridir. Campanula adiyamanensis Yıldırım & Özcan taksonu küresel ölçekte yok oluş ile karşı karşıyadır.
Ornithofauna of Bartın Sökü Wildlife Development Area
Authors: Kalkan İlkan , Özkazanç Nuri Kaan
Published: February 2024

Birds, which are important elements of biodiversity, are also an indicator of an ecosystem. However, this is only possible by knowing the bird species living in each region and their population densities. For this purpose, this study that we did, have based on two years of field observations. As a result of the observations and field studies carried out by point counting and line counting methods on nine different test routes, the species identified were identified, and their densities and their and status in the area were determined. Guidebooks were used to determine the species obtained of from the observations. As a result of the study, 53 different bird species belonging to 11 orders and 23 families were identified in the study area. Among the bird species identified, the Passeriformes order is the most common order in the area, with 34 different species, followed by the Falconiformes order, with five different species. They were identified species from Muscicapidae 8, Fringillidae 5, Paridae 4, Turdidae 4, Corvidae 3, Motacillidae 2, Sylvidae 2 and other families 1 in the Passeriformes order. In addition, 34 species identified in the area were native, 13 were summer migrants, 3 were winter migrants, and the remaining 3 were transit birds. Although it is a protected area, the intensive use of this area for wood production and the high hunter pressure in the area has been identified as the most important problems affecting the populations of bird species in the region. Determining the bird species of the Sökü Wildlife Development Area, where large mammal wild animals were previously identified, will contribute to other biodiversity studies to be carried out in the region.
Congenital and acquired forms of cytomegalovirus infection in infants
Authors:   Scientific and Research Institute for Children’s Infections of the Russian Federal Biomedical Agency, Saint Petersburg, Russia, Rogozina N.V. , Vasilyev V.V. ,   Scientific and Research Institute for Children’s Infections of the Russian Federal Biomedical Agency, Saint Petersburg, Russia,   North-Western State Medical University named after I.I. Mechnikov, Saint Petersburg, Russia, Markin I.V. ,   Scientific and Research Institute for Children’s Infections of the Russian Federal Biomedical Agency, Saint Petersburg, Russia, Ivanova R.A. ,   Scientific and Research Institute for Children’s Infections of the Russian Federal Biomedical Agency, Saint Petersburg, Russia,   Academician I.P. Pavlov First Saint Petersburg State Medical University, Saint Petersburg, Russia
Published: February 2024

Cytomegalovirus infection (CMVI) is a common viral disease. Differential diagnosis of congenital and acquired forms of the disease in infants is rather difficult. The purpose of this research was to describe the cytomegalovirus infection clinical features in infants depending on the management tactics. Materials and methods used: а retrospective study of 95 medical records of pediatric patients treated for CMVI in their first year of life. 3 groups were formed as follows: G1 of 40 with confirmed diagnosis of congenital CMVI, G2 (43) with an assumed diagnosis of congenital CMVI and G3 (12) with acquired CMVI (the comparison group). Results: the study of the clinical manifestations of both the congenital and the acquired CMVIs showed that the acquired form of the disease runs as manifested infection and is characterized by acute onset of the disease, moderate intoxication, increase in body temperature to febrile levels (33.3%), rhinitis, catarrhal tonsillitis and lymphadenitis (41.7%), bronchitis (16.7%) and neutropenia (50.0%). The incidence of detection of clinical manifestations associated with CNS lesions did not differ significantly between children with congenital CMVI and those with suspected congenital CMVI despite their detection at a later period (at the age of 3 to 6 months old): 30% and 34.9%, respectively, p=0.636. On the other hand, neutropenia was statistically significantly more common among children with suspected congenital CMVI (41.9%) than among those with congenital CMVI (6%), p=0.007. Conclusion: when CMV DNA is detected in the blood in infants, congenital CMVI cannot be excluded.