Submicroscopic Level Research Articles

Diagnosis of a fetus with a de novo 16q partial trisomy syndrome

To carry out prenatal diagnosis on a fetus with abnormal findings by ultrasonography and non-invasive prenatal testing. The fetus and both parents were subjected to chromosomal karyotyping and single nucleotide polymorphism array (SNP-array) analysis. The karyotypes of both parents were normal. The fetus carried a 46,N,der(X;16)(q28;q22) unbalanced translocation. SNP-array analysis confirmed that the derived chromosomal fragment of the fetus has originated from 16q. The fetus was diagnosed with 16q partial trisomy syndrome. Combined chromosomal karyotyping analysis and SNP-array can detect chromosomal aberrations at submicroscopic level and enable accurate diagnosis of the fetus.

Students’ Achievements in Solving Authentic Tasks with 3D Dynamic Sub-Microscopic Animations About Specific States of Water and their Transition

This paper aims to identify differences in the justification of the selection of 3D dynamic submicroscopic-representation (SMR) of the solid and liquid states of water, as well as the freezing of water presented in selected authentic tasks. According to students' achievements in solving these tasks at different levels of education, their explanations were identified. To explain in greater detail how students attempted to solve the authentic tasks, an eye-tracking method was used to identify the differences in the total fixation durations on specific areas of interest at the specific SMRs between successful and unsuccessful students in three age groups. A total of 79 students participated in this research. The data were collected with a structured interview conducted with students when solving three authentic tasks displayed on the computer screen. The tasks comprise text (as problem and questions), macro-images (photos of the phenomena) and SMRs of the phenomena. The eye-tracker was also used to measure the students' gaze fixations at the particular area of interest. The results show that successful students' justifications for a correct SMR include macroscopic and sub-microscopic representations of the chosen concepts. Along different stages of education, the selection success increases and sufficient justifications comprise the sub-microscopic level. It could be concluded that there are mostly no significant differences between successful and unsuccessful students within the same age group in the total fixation duration at the correct SMR. Further studies are needed to investigate the information-processing strategies between high and low achievers in solving various authentic tasks comprising SMRs and those that integrate all three levels of the representation of chemical concepts.

ANALISIS MODEL MENTAL SISWA MENGGUNAKAN TES DIAGNOSTIK MODEL MENTAL TWO-TIER (TDM-TWO-TIER) PADA MATERI LAJU REAKSI

AbstractThis research was instigated by student mental model that was not intact on Reaction Rate lesson. It aimed at analyzing and knowing student mental model through Two-Tier (TDM-Two-Tier) Mental Model Diagnostics Test instrument (TDM-Two-Tier) on Reaction Rate lesson at State Senir High School 2 Pekanbaru. This research was conducted at the first semester in the Academic Year of 2019/2020. It was Descriptive quantitative research. The data in this research were collected by Two-Tier (TDM-Two-Tier) Mental Model Diagnostics Test instrument, interview, and documentation. The collected data were analyzed by using Descriptive analysis. Purposive Sampling technique was used in this research. The samples of this research were 36 students at the eleventh grade of MIPA 2 of State Senior High School 2 Pekanbaru. The research findings showed that student mental model was not intact. It could be seen from the mean score of student mental model that was obtained from TDM-Two-Tier Diagnostics Test, Scientifically Correct (SC) of intact mental model or Scientifics was 47%, Partially Correct (PC) or partial mental model or alternative was 48%, students were able to understand the macroscopic level was 12%, symbolic level was 17% and submicroscopic level was 19% and Specific Misconception (SM) or misconception was 5%. Keywords: Mental Model, TDM-Two-Tier, Reaction Rate

MODEL MENTAL MISKONSEPSI PADA KONSEP KESETIMBANGAN KELARUTAN

Study on students' mental model's analysis was done to identify misconceptions about solubility equilibria concept. The method employed in the study was a case study uses a qualitative approach. The participants were 23 students of class XI of a senior high school in Bandung. The instrument used in the study was the Diagnostic Test on Mental Model-Prediction, Observation, Explanation (TDM-POE). The results showed that there were diverse of students' misconceptions about the precipitate formation of a reaction, the effect of common ions and decrease in pH on solubility. Based on the results of the study, many misconceptions occur in the subconcept of the effect of common ions on solubility. Misconceptions arise because students have incomplete mental models at the submicroscopic level.

Electron tomography: An imaging method for materials deformation dynamics

The combination of in-situ and three-dimensional (3D) in transmission electron microscopy (TEM) is one of the emerging topics of recent advanced electron microscopy research. However, to date, there have been only handful examples of in-situ 3D TEM for material deformation dynamics. In this article, firstly, the authors briefly review technical developments in fast tilt-series dataset acquisition, which is a crucial technique for in-situ electron tomography (ET). Secondly, the authors showcase a recent successful example of in-situ specimen-straining and ET system development and its applications to the deformation dynamics of crystalline materials. The system is designed and developed to explore, in real-time and at sub-microscopic levels, the internal behavior of polycrystalline materials subjected to external stresses, and not specifically targeted for atomic resolution (although it may be possible). Technical challenges toward the in-situ ET observation of 3D dislocation dynamics are discussed for commercial structural crystalline materials, including some of the early studies on in-situ ET imaging and 3D modeling of dislocation dynamics. A short summary of standing technical issues and a proposed guideline for further development in the 3D imaging method for dislocation dynamics are then discussed.

Smartchem: An Android Application for Learning Multiple Representations of Acid-Base Chemistry

An android application named SmartChem was developed to explain multiple representations of acid-base chemistry. This paper is a description of an android-based media (SmartChem) through the stages of design, development, validation and revision, and finally, limited trials with pre-service science teachers. SmartChem is intended to aid students in understanding through media explanations of symbolic, macroscopic, and submicroscopic representations of acid-base material. The validity of the tool was assessed through the ratings of a panel of five expert judges using Aiken’s validity index (Aiken’s V). The results show that some parts of the SmartChem media needed to be revised, especially in linking submicroscopic level content with symbolism. From the trials of this application with trainee teachers, help in understanding multiple chemical representations of acids and bases was demonstrated; however, the low achievement group was more concerned with technical features, while the higher achieving group appreciated the content and learning experience.

APPLICATION OF THE CRITERION OF TECHNOLOGICAL DAMAGEABILITY IN MECHANICAL ENGINEERING

Development and implementation in mechanical engineering practice of integrated information systems for control of technological processes of manufacturing products is the main driver of economic growth of developed countries. The priority of modern engineering technology is to provide the specified operational characteristics of products in accordance with the accuracy parameters, set by designer and quality of surface layers in contrast to achieving the minimum technological cost with maximum performance for traditional approaches. Technological providing of the main operational characteristics of the product (bearing strength, wear resistance, fatigue strength, joint strength etc.) require a systematic approach, which consists in the investigation of real physical processes at submicroscopic, microscopic and macroscopic levels of research, and step- by-step tracking required parameters at all stages of the Product Life Cycle from the position of technological inheritability. It is proposed to use the method of LM-hardness to control the quality of the structure of the material from castings in the design of functionally-oriented processes. The magnitude of the technological damage of the product material serves as a criterion for optimization when choosing a variant of surface treatment of the casting. A method for providing experimental studies of castings of aluminium alloys has been developed. On the basis of the carried-out experimental researches the rational route of processing of surfaces of casting is chosen.

Learning Media Based on Three Level Representation and Inquiry for Electrolysis Cell Materials

Research has been conducted aimed at designing three-level representation-based learning media in electrolytic cell material. The research product in the form of a model kit equipped with inquiry-based worksheets was developed through the stages of design based research. The model kits and worksheets produced have the characteristics: integrating macroscopic, submicroscopic and symbolic levels of representation, developing the ability of chemical representation and scientific performance. The submicroscopic and symbolic representations are explored using particle models made of magnetism to simulate the transfer of ions and electrons during an electrolysis reaction. Validation and testing of products and inquiry-based worksheets show the product is valid and feasible to use.

Students Mental Models of Solid Elasticity: A Mixed Method Study

A mental model (MM) is an internal representation of students’ conceptual understanding. Currently, students have still had difficulties in explaining the physical state of elasticity of solid materials, at sub-microscopic level. These difficulties call for this research. Through a mixed method, the study aimed to reveal the development and differences of students’ mental models after physics learning with problem -based learning (PBL) and conventional methods. Indicators of students’ mental models were adapted from SMD model. Findings suggested that the PBL resulted in more MM, whilst conventional classes emerged MM on the elastic and plastic objects. Meanwhile, the lowest MM achievements ware Hooke’s Law for the PBL, and series and parallel springs for the conventional class. N-Gain values of the students’ mental models at PBL and conventional classes were found to be 0.64 and 0.43 respectively. On the other hand, mental model scores of the PBL learning model was higher (23.77%) than those of the conventional learning model. Thus, it can be concluded that the PBL learning model is effective in improving the students’ mental models of physics. This research recommends that students’ understanding of physics concepts should be increased at macroscopic and sub-microscopic levels.

The influence of selected treatment parameters with atmospheric plasma on the treatment process and wood wettability

The paper presents the use of low-temperature plasma, generated in the air at atmospheric pressure, for treatment of wood surfaces to improve their wettability. For this purpose, a dielectric barrier discharge plasma device with a floating electrode configuration was used. The density and homogeneity of the plasma discharge, formed between the isolated high voltage electrodes and the surface of the spruce (Picea abies (L.) Karst.) and beech (Fagus sylvatica L.) wood, was shown to be highly dependent on the size of the gap between the electrode and wood. Topography measurements using a confocal laser microscope showed that exposure of wood to plasma causes changes on its surface at the sub-microscopic level. Measurements of the contact angles of water droplets and water-based coating showed the improved susceptibility to wetting of treated surfaces. Differences in surface wettability were also detected depending on the selected machining parameters: type of wood, workpiece feed speed, the distance between the electrodes, the distance between the electrodes and workpiece, and workpiece thickness.

Plasmodium falciparum immunodominant IgG epitopes in subclinical malaria

Incomplete non-sterile immunity to malaria is attained in endemic regions after recurrent infections by a large percentage of the adult population, who carry the malaria parasite asymptomatically. Although blood-stage Plasmodium falciparum rapidly elicits IgG responses, the target antigens of partially protective and non-protective IgG antibodies as well as the basis for the acquisition of these antibodies remain largely unknown. We performed IgG-immunomics to screen for P. falciparum antigens and to identify epitopes associated with exposure and clinical disease. Sera from malaria cases identified five prevalent antigens recognized by all analyzed patients’ IgGs. Epitope mapping of them, using adult and children sera samples from an endemic malaria region in Ghana segregated into patients with positive or negative subclinical detection of P. falciparum, revealed binding specificity for two 20-mer immunodominant antigenic regions within the START-related lipid transfer protein and the protein disulfide isomerase PDI8. These 20-mer epitopes challenged with sera samples from children under 5 years old displayed specific IgG binding in those with detectable parasitemia, even at subclinical level. These results suggest that humoral response against START and PDI8 antigens may be triggered at submicroscopic parasitemia levels in children and may eventually be used to differentially diagnose subclinical malaria in children.

Алгоритм интерпретации клинической значимости хромосомных микродупликаций при недифференцированных формах интеллектуальных расстройств

Идентификация хромосомных аномалий на субмикроскопическом уровне и установление их роли в этиологии интеллектуальных расстройств являются важной научной и практической задачей. Оценка патогенного значения менее изученного типа вариаций копийности ДНК - хромосомных микродупликаций представляет актуальный предмет для обсуждения. В исследовании предложен алгоритм интерпретации клинической значимости частичных трисомий, который является неотъемлемой составляющей в диагностике и профилактике хромосомных болезней. The identification of chromosomal abnormalities at the submicroscopic level and the establishment of their role in the etiology of intellectual disorders are an important scientific and practical task. Evaluation of the pathogenic value of the less studied type of copy number variation - chromosomal microduplication - is an actual issue. The study proposed an algorithm for interpreting the clinical significance of partial trisomies, which is an integral component in the diagnosis and prevention of chromosomal diseases.

Exploring Cluster Changes in Students’ Knowledge Structures Throughout General Chemistry

Chemistry is traditionally perceived as difficult to comprehend. Its mastery requires that a variety of concepts be linked to form an organized knowledge system. The connections need to be made not only between the concepts associated with the macroscopic level of the chemistry triplet but also between the submicroscopic and symbolic levels. Many factors influence a learner’s success in bridging concepts between these levels. In this study, the aim was to identify and examine the changes in general chemistry students’ knowledge structures by utilizing Word Association Tests. Although many studies have examined knowledge structures and aspects of the chemistry triplet, almost none has considered both at the same time. This study highlights the interconnectedness between the chemistry triplet and changing knowledge structures in overall student populations and in high- and low-achieving students. It provides insights on why students fail to understand chemistry and suggests ideas for future research as limiting factors were noted.

Chemistry Education in Bosnia and Herzegovina

In this paper, the education system in Bosnia and Herzegovina is presented in the light of current state-level legislation, with an emphasis on chemistry education at the primary, secondary and tertiary level. The consequences of the last war in our country still persist and are visible in many aspects of everyday life, including the education system, thus limiting the efforts of education professionals to follow international trends in education. There are three valid curricula for primary education at the national level, each of which differs in the national group of school subjects. Teaching methods are common for all three curricula and are mainly teacher-oriented. The situation is similar with regard to secondary education. Study programmes at the university level are organised in accordance with the Bologna principles. The programmes are made by the universities themselves and approved by the corresponding ministry of education. Chemical education research in Bosnia and Herzegovina is mainly conducted at the University of Sarajevo. It deals with (1) the problems of experimental work in chemistry teaching, resulting in more than 60 experiments optimised for primary and secondary school, (2) integrating the knowledge of chemistry, physics and physical chemistry for university students, with regard to students’ difficulties observed during university courses and potential solutions, and (3) the effectiveness of web-based learning material in primary school chemistry for the integration of macroscopic and submicroscopic levels. For the purpose of this paper, official documents for primary, secondary and higher education have been used.

Design of a didactical resource to introduce chemical formulas in secondary school

This paper presents the research conducted to create a history-of-science-based resource that would introduce students to chemical formulas in secondary education in France. This elaboration is based on theoretical frameworks dealing with educational reconstruction of teaching-learning sequences and on the analysis of teaching practices. Preliminary empirical investigations conducted with students and some teachers show the need to articulate the registers of models, reality and language at the submicroscopic and macroscopic levels for learning the concepts of chemical change and chemical reaction. The first part of the resource is implemented in the classroom. The second part that allows to write the reasons justifying the chemical formulas is rejected by two teachers. This leads to a first proposal of the evolution of the resource.

Modern ideas about morphological changes in the cerebellar cortex under influence of factors of different origin

The work is a fragment of scientific research “Peculiarities of structural reorganization of the nervous, digestive, endocrine systems, hematopoietic and immune organs under conditions of thermal injury and the use of corrective factors” (0120U104152).The study of the state of internal organs and systems of the body under the influence of external factors that are stressful is relevant. The negative impact of environmental factors on the central nervous system, including cerebellum, leads to their structural and functional restructuring. The cerebellum is a multifunctional component of the brain and the object of numerous lesions.The purpose of this work is analysis of scientific literature which is dedicated study of the influence of exogenous and endogenous factors on the morphological structure of the cerebellum.The article analyzes the scientific literature of the effects of hypodynamia, hypothermia, hypokinesia, alcohol intoxication, toxic effects of Lead, drugs, pharmacological agents, low-frequency pulsed electromagnetic field on the micro- and submicroscopic organization of the cerebellum. In lots of experimental studies, which were analyzed it is established that in the dynamics of the influence of different factors there is a reorganization of the cerebellar cortex layers and disruption of the microcirculatory bed structures. Purkinje cells change shape to spherical, their processes are thinned, sharply hyperchromic neurocytes prevail over normochromic ones. The functional activity of neurons is reduced, because the chromatophilic substance is almost absent. The thickness of the molecular and granular layers decreases. The ganglionic layer loses its single-row arrangement of neurons. There are erythrocytes in the coin columns in the lumens of hemocapillaries. The dilatation and prevascular edema are observed. Thus, under the conditions of negative influence of various factors in neurocytes of a cerebellar cortex and links of a microcirculatory channel there are destructive and degenerative changes on micro- and submicroscopic levels. In the long run there are adaptive-compensatory processes and necrotic, which had a phase dependence. So, destructive and degenerative changes on micro- and submicroscopic levels. In the long run there are adaptive-compensatory processes and necrotic, which had a phase dependence.

Stages of development electronic chemistry book on acid and base use 4S TMD models with STES approach

The purpose of this study was to development electronic chemistry book on acid and base use 4S TMD models with STES approach. 4S TMD models consist of selection, structuring, characterization, and didactic reduction. This study method is the first part of the development of teaching materials which includes selection and structuring steps. The study method is Development Research (DR) that consists of design, development, and evaluation. The design stage was to analyze and plan the types of teaching materials instructional developed. There are 13 indicators from 2 standard competencies that produced in selection step based curriculum, the compatibility subject matter and indicators, and the relations between value and subject matter. Explains the concept of acid-base using standardized textbook sources, and analyzes STES that can be integrated with the concept of acid base. In the structuring step, concept maps, macrostructures, and multiple representations are developed that connect between representations of macroscopic, submicroscopic and symbolic levels. The result of the selection and structuring steps are evaluated by expert lecturers. The first part of the development of teaching materials which includes the selection and structuring steps resulted in a draft of electronic chemistry book on acid-base with STES approach. This study reaches the structuring stage, then characterization and didactic reduction stage will be followed up.

Adrenal glands: morphofunctional reorganization based on the influence of exogenous and endogenous factors

The adrenal glands are the subject of many researches in biology and medicine. They have unique histoarchitectonics of the parenchyma and structure of the bloodstream. They also perform a number of important functions necessary for the normal vital activity of the body under stress. A large number of scientific papers are devoted to the study of changes in the structural organization of this organ at the micro- and submicroscopic levels under the influence of various external and internal factors. Morphofunctional changes in the gland after experimental thermal burns of the skin remain poorly understood, which requires further experimental studies in this area.The purpose of this study was to review the scientific literature on the effects of factors of different origins on the morphofunctional structure of the adrenal glands.The article analyzes scientific publications devoted to the study of the effects on the adrenal morphology of stress factors, heavy metals, drugs and toxic substances, alcohol, smoking, starvation, hypergravity, physical exercises, hypothermia, poisoning, dehydration, drugs, diabetes, and viral infections. It was found that the factors we mentioned cause the reorganization of the structural components of the adrenal glands, violations of their histoarchitectonics, in particular microcirculatory bed, at the micro- and submicroscopic level. In most cases, there were phenomena of pericellular and perivascular edema, focal hemorrhage, connective tissue growth, thickening of the connective tissue capsule of the organ with signs of edema, vacuolation and edema of the cytoplasm, and the appearance of pyknotic nuclei. In the long term that followed after the experiment, the stabilization of morphofunctional elements of the gland and the microcirculatory bed was recorded, but complete restoration of the structural integrity of the organ did not occur.

Linking the submicroscopic and symbolic level in physical chemistry: how voluntary simulation-based learning activities foster first-year university students’ conceptual understanding

Research in the past decades repeatedly revealed university students’ struggles to properly understand physical chemistry concepts. In contrast to school, tertiary teaching relies heavily on the symbolic level, mainly applying abstract representations such as equations and diagrams. To follow the lessons and generate conceptual understanding, students need to connect those representations with macroscopic and submicroscopic aspects of the scientific concept depicted. For German first-year chemistry students, this increase in abstraction in a major subject of study contributes to excessive demand and demotivation (especially during out-of-class learning) and increases the risk of early dropouts. We designed a simulation-based learning environment (BIRC: Bridging Imagination and Representation in Chemistry) to suit the needs of first-year students and support them when learning physical chemistry at home. Our approach, featuring molecular dynamics simulations, requires students to assess their own mental models on the submicroscopic level and connect them to equations and diagrams on the symbolic level. Prior studies did already highlight the potential of individual BIRC learning units to foster conceptual understanding on specific topics. In this paper, we investigate if and how students of a broader sample use these learning activities as voluntary supplement beside regular coursework. During the term, we used think-aloud protocols, interviews and eight online questionnaires to analyse students’ mental and emotional interaction while working on BIRC, assessing whether students perceived BIRC as a suitable, enjoyable and supportive resource to enhance learning. Via two paper & pencil achievement tests we examined students’ retention concerning submicroscopic mental models and their ability to connect these mental models with symbolic representations 5–10 weeks later. Our findings indicate a cognitively engaging, comparably enjoyable learning process, which strengthens conceptual understanding and – despite the necessary time and effort – induces a broad number of students to voluntarily work on several units at home.

Transitions between representational levels: characterization of organic chemistry students’ mechanistic features when reasoning about laboratory work-up procedures

Chemists refer to chemical phenomena on different representational levels—macroscopic, symbolic, and submicroscopic—which are directly related and connected to each other. Especially in the laboratory, students have to reason about various mechanistic features at the submicroscopic level and connect them in a meaningful way to make sense of the observable. There is plenty of evidence in chemistry education that students have difficulty connecting the different representational levels when thinking about chemical phenomena. However, current literature provides limited information about the mechanistic features that students activate when reasoning about phenomena and how they transition between the representational levels when in an organic chemistry laboratory. In this study, we performed in-depth analysis of how organic chemistry student teachers (N = 9) explained typical work-up procedures and characterized their activated mechanistic features and transitions between the different representational levels. Our analysis revealed that the students do not activate all features of a mechanism in the same way and construct various explanatory approaches. The findings emphasize the need to explicitly communicate how to connect the macroscopic and submicroscopic levels in a meaningful way in the laboratory. The implications of these findings for research, teaching, and learning to foster meaningful activation of mechanistic features are discussed.