Basic Fraction Research Articles

MEGA GASTROPODA ASSOCIATION IN THE MONOSPECIFIC SEAGRASS MEADOWS OF BADAK BADAK ISLAND, BONTANG CITY

Mega Gastropods play an important role in the food chain in bottom waters. Mega Gastropods are associated with seagrass beds which have sand and sandy mud bottom substrates. The aim of the research is to determine the association of Mega Gastropods in monospecific seagrass beds as their habitat. This research was carried out from October 2023 - February 2024 in the seagrass beds of Badak Badak Island. The station is divided into 3 stations and each station is divided into 3 zones. Seagrass and Mega Gastropod samples were taken using a 50x50cm quadrant frame. The relationship between seagrass density and Mega Gastropod density was used by the Pearson's Product Moment correlation test and the distribution of basic substrate fractions and the distribution of Mega Gastropod species was used by Principal Component Analysis (PCA) and Corespondence Analysis (CA). The Mega Gastropods found consisted of L. turturella, C. tigris, P aluco, and T. telescopium. The relationship between Mega Gastropod density and E. acoroides density was not positively correlated and the presence of Mega Gastropod species was associated with the characteristics of the basic substrate fraction.

Basic mathematical skills and fraction understanding predict percentage understanding: Evidence from an intelligent tutoring system

Research on fostering learning about percentages within intelligent tutoring systems (ITSs) is limited. Additionally, there is a lack of data‐driven approaches for improving the design of ITS to facilitate learning about percentages. To address these gaps, we first investigated whether students' understanding of basic mathematical skills (eg, arithmetic, measurement units and geometry) and fractions within an ITS predicts their understanding of percentages. We then applied a psychological network analysis to evaluate interdependencies within the data on 44 subtopics of basic mathematical concepts, fractions and percentages. We leveraged a large‐scale dataset consisting of 2798 students using the ITS bettermarks and working on approximately 4.1 million mathematical problems. We found that advanced arithmetic, measurement units, geometry and fraction understanding significantly predicted percentage understanding. Closer inspection indicated that percentage understanding was best predicted by problems sharing similar features, such as fraction word problems and fraction/natural number multiplication/division problems. Our findings suggest that practitioners and software developers may consider revising specific subtopics which share features with percentage problems for students struggling with percentages. More broadly, our study demonstrates how evaluating interdependencies between subtopics covered within an ITS as a data‐driven approach can provide practical insights for improving the design of ITSs. Practitioner notesWhat is already known about this topic Longitudinal studies showed that basic mathematical skills predict fraction understanding. There is only limited evidence on whether similar predictions can be observed for percentage understanding—in general and within intelligent tutoring systems. Process data from such intelligent tutoring systems can be leveraged to pursue both educational research questions and optimizing digital learning software. Problems involving percentages typically are word problems requiring multiplications and/or divisions. What this paper adds Similar to the case of fractions, students' performance on advanced arithmetic, measurement units and geometry significantly predicted performance with percentages. Students' performance with fractions also predicted performance with percentages significantly. A psychological network analysis was applied to evaluate specific interdependencies between a range of subtopics (eg, Multiplying and dividing fractions, Adding and subtracting fractions and Calculating with percentages). Fraction word problems and fraction problems involving multiplication/division turned out to be the best predictors of understanding percentages. Implications for practice and/or policy When facing difficulties with percentages, revision of previous mathematical concepts sharing similar features (eg, fraction word problems, fraction/natural number multiplication/division problems) may be advised. Software developers may consider implementing such data‐driven revision recommendations for students facing difficulties within intelligent tutor systems. Psychological network analysis can be utilized as a learning analytics method for easy‐to‐access visualizations illustrating relationships between a large range of different subtopics.

SECONDARY POLYMERS AS A PROSPECTIVE RAW MATERIAL FOR THE PRODUCTION OF HIGH-OCTANE AUTOMOBILE GASOLINE

The article analyzes the possibility of expanding the raw material base of the production process of commercial high-octane automobile gasoline of the A-92 and A-95 brands due to the involvement of secondary polymer raw materials. The types of raw materials that will make it possible to obtain basic fractions or components of commercial gasolines that will be used in the production of commercial automobile gasolines that, according to their chemical composi- tion and properties, will meet the requirements of environmental safety standards adopted in Ukraine and the countries of the European Union have been determined. It was established that the main raw material capable of replacing oil and gas condensate is secondary polyolefin raw material, represented by polyethylene (HDPE and LDPE) and polypropylene (PP), and the main process of its processing is thermal or thermocatalytic pyrolysis. Priority is given to raw materials that are directly generated in production in the form of waste and raw materials that come from sorting points. At the same time, secondary polymer raw materials, regardless of their source of origin, must undergo a stage of preliminary preparation, which includes sorting, crushing, washing and drying of raw materials. Practical studies have shown that this process is implemented on reactor-type installations at temperatures of 320–450 °C and pressures of 0.1–3.5 MPa and allows obtaining a significant yield (35–70 %) of the liquid product of pyrolysis – a gasoline fraction with a boiling point of 30–200 °C. Along with liquid products, more than 15 % of gases (ethylene, propylene and butylene) are formed, which should be processed into polymer gasoline (base fraction) and high-octane components – alkylates. As a result of the research, a scheme for the production of commercial high-octane automobile gasoline from secondary polymer raw materials (HDPE, LDPE and PP) is proposed, which is based on the rational use of production resources and production by-products.

Determination of Ways of Improving the Process of Separation of Seed Materials on the Working Surface of the Pneumatic Sorting Table

Abstract The object of the study is the process of separation of seed material according to the seed density on the working surface of the pneumatic sorting table. The main defining design variables and linkage parameters of the equipment are analyzed, which realizes the process of separation of seed materials, and is coordinated with physical and mechanical variables of raw materials. The principles of modeling of seed material layer movement as a multiphase medium are provided. Under the effect of working surface vibrations and the power of an airstream the layer take on the properties of pseudoliquid. The criteria of chosen variables are presented, on which depend quality and quantity indicators of the separation process of seed materials according to the seed density. Optimal values of the separator linkage parameters are analytically determined and dependence diagrams are built. Secant lines of surfaces for a concrete crop (raw material) are performed. The “purity” of heavy fraction during the variation of indicated parameters is studied. It is proved that there are differences in types of the dependences: different decreasing of functions and increasing of airstream velocity. It is obvious that this nature is determined by difference in density of original raw materials. This way the smallest influence a change in the air-stream velocity causes to soybean raw material, as soybean has the biggest density. At the same time, the biggest affect is provoked on sunflower seeds, which have the smallest density among the used types of raw materials, as well as a triangle form. It is determined that the maximal frequency of the basic fraction, gained by the separation of wheat seed material on PST, is obtained under the airstream velocity in the range 1.3-1.5 m·s−1. For corn the rational air-stream velocity falls in the range 1.3-1.6 m·s−1, for sunflower – 1.2-1.4 m·s−1, for soybean – 1.2-1.4 m·s−1. These figures are valid under the condition of using the relevant rational decisions of frequency and amplitude of vibrations of pneumatic sorting table deck during the separation of grain mixtures, as well as longitudinal and transverse angles of inclination. The veracity of experimental studying results is proved by the corresponding theoretical models of the process.

Learning trajectory in the material of comparing and ordering fractions using paper folding for elementary school students

Background:Understanding fractions in mathematics often poses greater complexity compared to integral numbers. The primary difficulty lies in students' inadequate grasp of fractional basics, notably in comparing and sequencing fractions.Aim: This research seeks to create and evaluate a learning pathway's effect on fourth graders' comprehension of fractions, with a focus on their comparison and sequencing.Method: Employing a design research validation study approach, the research progresses through preliminary design, experimental design, and retrospective analysis. Conducted in a Palembang school involving six fourth graders recommended by their teacher, data collection encompassed essay-based pre and post-tests, Student Activity Sheets, observations, interviews, and documentations. The data analysis was retrospectively carried out, anchored on HLT as the benchmark.Result: Findings reveal a student learning trajectory encompassing three principal activities. Initially, students used folding and gluing of paper to discern fraction values. Subsequently, they engaged in coloring and illustrating folds for fraction comparison. The final activity involved drawing, coloring boxes, and fraction comparison and sequencing. Overall, students showed proficiency in understanding and determining fraction values and comparing them, yet struggled with ordering certain fractions.Conclusion: The structured learning path facilitated students' understanding of basic fraction concepts, especially in comparing them. Nevertheless, reinforcing methods or approaches for teaching fraction ordering is essential.

Antidiabetic property of fractions and pure compounds from Andrographis paniculata

Chlorophyll-free fractions of Andrographis paniculata were investigated for glucose uptake and lipid reduction in 3T3-L1 adipocytes. At 25 µg/ml, the acid fraction concentration enhanced glucose uptake by 82%. Basic and neutral fractions at 100 µg/ml enhanced glucose uptake by 82% and 78%, respectively. The three fractions showed improved glucose uptake compared to the crude extract (25% uptake at 50 μg/ml). GC-MS analysis of the fractions revealed the presence of chemicals with antidiabetic activities. The neutral fraction was prioritised for pure compound isolation to provide known andrographolide (1), 14-deoxyandrographolide (2), and a novel compound, 3-epi-11,12-didehydro-14-deoxyandrographolide (5). At a concentration of 1 µM, compounds 2 and 5 are as effective as 10 mM metformin in glucose uptake. They also reduce lipid accumulations in 3T3-L1 adipocytes by decreasing the size and number of lipid droplets. The activities of fractions and compounds support the use of A. paniculata in treating type 2 diabetes.

Carbon Fluxes in Potato (Solanum tuberosum) Remain Stable in Cell Cultures Exposed to Nutritional Phosphate Deficiency.

Nutritional phosphate deficiency is a major limitation to plant growth. Here, we monitored fluxes in pathways supporting respiratory metabolism in potato (Solanum tuberosum) cell cultures growing in control or limiting phosphate conditions. Sugar uptake was quantified using [U-14C]sucrose as precursor. Carbohydrate degradation through glycolysis and respiratory pathways was estimated using the catabolism of [U-14C]sucrose to 14CO2. Anaplerotic carbon flux was assessed by labeling with NaH14CO3. The data showed that these metabolic fluxes displayed distinct patterns over culture time. However, phosphate depletion had relatively little impact on the various fluxes. Sucrose uptake was higher during the first six days of culture, followed by a decline, which was steeper in Pi-sufficient cells. Anaplerotic pathway flux was more important at day three and decreased thereafter. In contrast, the flux between sucrose and CO2 was at a maximum in the mid-log phase of the culture, with a peak at Day 6. Metabolization of [U-14C]sucrose into neutral, basic and acidic fractions was also unaffected by phosphate nutrition. Hence, the well-documented changes in central metabolism enzymes activities in response to Pi deficiency do not drastically modify metabolic fluxes, but rather result in the maintenance of the carbon fluxes that support respiration.

Narcissus pseudonarcissus L. (Amaryllidaceae) bulb metabolite profiling and biological activities

Various metabolomics approaches have greatly contributed to the study of natural products from medicinal plants. Among thousands of plant species, Narcissus pseudonarcissus L. (Amaryllidaceae) is reputed for its ornamental, industrial, and medicinal applications. This plant is also used traditionally for microbial infections, inflammations, skin complaints, and cancers. Long ago, N. pseudonarcissus has gained considerable research interest thanks to its diverse alkaloids that have been widely studied. However, the non-alkaloidal principles and different bioactivities of this plant were poorly deliberated in previous works. Therefore, this work evaluates the biological potential of N. pseudonarcissus bulbs′ total ethanol extract (TEE) and its derived fractions (I‒IV), along with exploring the overlooked non-alkaloidal metabolites of this amaryllid. Overall, GC‒MS-based analysis of the bulbs led to the identification of varied metabolites, e.g., long-chain alkyl amines, alkylbenzenes, long-chain hydrocarbons, fatty acid derivatives, and phenylpropanoids. Most of these phytochemicals are first characterized herein in either the genus Narcissus or the family Amaryllidaceae. Additionally, the acidic EtOAc fraction (II) exhibited the highest scavenging potential of the 2,2′-diphenyl-1-picrylhydrazyl radical and the greatest ferric reducing power, possibly due to its relatively higher contents of phenolics and flavonoids that were also estimated herein. On the other hand, the basic EtOAc fraction (III) exerted the maximum anti-proliferative actions against Caco-2 (colon) and Mcf-7 (breast) tumor cells, while all of the tested fractions were inactive against HepG-2 (liver) cancer cells. Finally, different N. pseudonarcissus fractions demonstrated varied inhibitory activities against a group of pathogenic bacteria and fungi. Among them, fractions II and III were further observed as good synergists with some standard antimicrobial agents, even against some resistant microbial strains. These data could support the reported use of N. pseudonarcissus in traditional medical systems and help widen its future phytochemical and biological prospection.

High-Field Asymmetric Waveform Ion Mobility Spectrometry Analysis of Carcinogenic Aromatic Amines in Tobacco Smoke with an Orbitrap Tribrid Mass Spectrometer.

Smoking is a risk factor for bladder cancer (BC), although the specific chemicals responsible for BC remain uncertain. Considerable research has focused on aromatic amines (AAs), including o-toluidine (o-tol), o-anisidine (o-anis), 2-naphthylamine (2-NA), and 4-aminobiphenyl (4-ABP), which are linked to human BC based on elevated BC incidence in occupationally exposed factory workers. These AAs arise at nanogram levels per combusted cigarette. The unambiguous identification of AAs, particularly low-molecular-weight monocyclic AAs in tobacco smoke extracts, by liquid chromatography-mass spectrometry (LC-MS) is challenging due to their poor performance on reversed-phase columns and co-elution with isobaric interferences from the complex tobacco smoke matrix. We employed a tandem liquid-liquid and solid-phase extraction method to isolate AAs from the basic fraction of tobacco smoke condensate (TSC) and utilized high-field asymmetric waveform ion mobility spectrometry (FAIMS) coupled to high-resolution accurate mass (HRAM) Orbitrap LC-MS2 to assay AAs in TSC. The employment of FAIMS greatly reduced sample complexity by removing precursor co-isolation interfering species at the MS1 scan stage, resulting in dramatically improved signal-to-noise of the precursor ions and cleaner, high-quality MS2 spectra for unambiguous identification and quantification of AAs in TSC. We demonstrate the power of LC/FAIMS/MS2 by characterizing and quantifying two low-molecular-weight carcinogenic AAs, o-tol and o-anis, in TSC, using stable isotopically labeled internal standards. These results demonstrate the power of FAIMS in trace-level analyses of AA carcinogens in the complex tobacco smoke matrix.

Deadwood affects the soil organic matter fractions and enzyme activity of soils in altitude gradient of temperate forests

The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils. For this purpose, a climosequence approach comprising north (N) and south (S) exposure along the altitudinal gradient (600, 800, 1000 and 1200 ​m a.s.l.) was set up. By comparing the properties of decomposing deadwood and those of the soils located directly beneath the decaying wood we drew conclusions about the role of deadwood in the shaping of soil organic matter fractions and soil carbon storage in different climate conditions. The basic properties, enzymatic activity and fractions of soil organic matter (SOM) were determined in deadwood and affected directly by the components released from decaying wood. Heavily decomposed deadwood impacts soil organic matter stabilization more strongly than the less decayed deadwood and the light fraction of SOM is more sensitive to deadwood effects than the heavy fraction regardless of the location in the altitude gradient. Increase in SOM mineral-associated fraction C content is more pronounced in soils under the influence of deadwood located in lower locations of warmer exposure. Nutrients released from decaying wood stimulate the enzymatic activity of soils that are within the range of deadwood influence.

In-Depth Blood Proteome Profiling by Extensive Fractionation and Multiplexed Quantitative Mass Spectrometry.

Blood in the circulatory system carries information of physiological and pathological status of the human body, so blood proteins are often used as biomarkers for diagnosis, prognosis, and therapy. Human blood proteome can be explored by the latest technologies in mass spectrometry (MS), creating an opportunity of discovering new disease biomarkers. The extreme dynamic range of protein concentrations in blood, however, poses a challenge to detect proteins of low abundance, namely, tissue leakage proteins. Here, we describe a strategy to directly analyze undepleted blood samples by extensive liquid chromatography (LC) fractionation and 18-plex tandem-mass-tag (TMT) mass spectrometry. The proteins in blood specimens (e.g., plasma or serum) are isolated by acetone precipitation and digested into peptides. The resulting peptides are TMT-labeled, separated by basic pH reverse-phase (RP) LC into at least 40 fractions, and analyzed by acidic pH RPLC and high-resolution MS/MS, leading to the quantification of ~3000 unique proteins. Further increase of basic pH RPLC fractions and adjustment of the fraction concatenation strategy can enhance the proteomic coverage (up to ~5000 proteins). Finally, the combination of multiple batches of TMT experiments allows the profiling of hundreds of blood samples. This TMT-MS-based method provides a powerful platform for deep proteome profiling of human blood samples.

Biological Study on Aerial Parts of Hyoscyamus boveanus (Dunal) Asch. & Schweinf

Family Solanaceae is one of the largest families in the plant kingdom. A family of 98 genera and over 2700 species; tropical and temperate; herbs, shrubs or small trees.
 Secondary metabolites of Solanaceae plants, sharing tropane skeleton as a common structural feature, sharply divided into two classes: tropine and ecgonine derivatives. The first group, represented by well-known alkaloids: atropine and scopolamine, which are considered to be model anticholinergic drugs, continues to provide inspiration in the search for more selective muscarinic receptor antagonists. This work, aim to study the biological effect of Hyoscyamus boveanus alkaloid fraction as Antimuscarenic, mydriatic and anti microbial agent. Basal alkaloid fraction was isolated from collected wild plant by using authentic atropine (sigma USA). Fifteen rabbits weighing 1700 – 2000 gram used in this study, divided into three groups (5 each); control (solvent) group, standard (atropine) group and the Hyoscyamus boveanus Dunal basic alkaloid fraction group. Two cm rabbit intestine muscle was isolated to study anti spasmodic activity of the basic alkaloid fraction of Hyoscyamus boveanus Dunal. As well as, anti microbial activity of Hyoscyamus boveanus basal alkaloid fraction was studied. The results revealed that Hyoscyamus boveanus basal alkaloid fraction showed mydriatic, Antimuscarenic and anti microbial activity against gram negative and gram-positive bacteria. In conclusion, Hyoscyamus boveanus Dunal basic alkaloid fraction, showed mydriatic, Antimuscarenic and anti microbial activity against gram negative and gram-positive bacteria.

Isolation, crystal structure, DFT calculation and molecular docking of uncinatine-A isolated from Delphinium uncinatum

The main objective of our present research work was to explore molecular insight for potentially active new acetylcholinesterase inhibitor from the aerial parts of Delphinium uncinatum. New norditerpenoid alkaloids, uncinatine-A, was isolated from the basic alkaloidal fraction of D. uncinatum, based on bioactivity guided isolation. The structure of uncinatine-A was determined through latest spectroscopic techniques including single X-Ray diffraction technique. The structural data and electronic properties of uncinatine-A was also calculated by Density Functional Theory (DFT) using B3LYP/6-31þ G (p) basis set. The isolated natural product was evaluated for their acetyl cholinesterase inhibitory potential in dose dependent protocol (62.5–1000 μg/mL), followed by molecular docking studies. Significant competitive type inhibition activity (IC50 = 207.73 ± 0.3) was shown by isolated natural norditerpenoid against cholinesterase targets in comparison with standard drugs available in the market such as galanthamine. The molecular docking results showed that isolated natural product was well accommodated by AChE in the active site with docking scores −11.0326. This is the first report indicating uncinatine-A as a potent acetylcholinesterase inhibitor and can be used as a target drug in cerebral dementia and Alzheimer diseases.

Effect of hydrochloric polyhexamethylene guanidine (PHMGH) and polyhexamethylene biguanidine (PHMBH), also in combination with plant essential oils and ZnO nanoparticles on some eukaryotic cattle and pig cells

Aim. To investigate both toxic (hemolytic), and stimulating effects of two polymeric derivatives of guani- dine, in particular, polyhexamethylene guanidine (PHMG) and polyhexamethylene biguanidine (PHMB) both in the hydrochloride form, on eukaryotic cells depending on the concentration of the preparation; to study the possibility of using wound-healing and stimulating properties of these preparations in veterinary medicine. Methods. The hemolytic activity (toxicity) of PHMGH and PHMBH preparations in the concentration of 0.1% towards cattle and pig erythrocytes was determined by titration. Primary cell cultures of fetal kidney cells of calves and piglets were used to determine the influence of PHMGH and PHMBH both alone and in combination with the following biologically active substances: essential oils of Pinus sylvestris, Eucalyptus globulus, Citrus sinensis, Monarda didyma, ZnO nanoparticles (size c. 25 nm), and electrochemically acti- vated water – anolyte (Eh = –800 mV, pH 6.5–7.0). The concentration of the cells in the nutrient medium was determined via photocolorimetry. Results. It was found that depending on the concentration, PHMGH, and PHMBH preparations can cause the lysis of erythrocytes, and stimulate cell proliferative activity, including the formation of a monolayer of kidney cells of calves and piglets They cause hemolysis of cattle erythro- cytes in the concentrations commonly used for disinfection, i.e., about 0.1 %, in the average titers of 1 : 7 for PHMGH and 1 : 2.5 for PHMBH. Therefore, PHMBH shows greater hemolytic (biocidal) activity for cattle erythrocytes than PHMGH (in ≈2.8x). The high molecular weight fraction of PHMBH (M2 ≈ 2,000–7,000 Da) demonstrated a lower (in ≈2.4x) hemolytic activity than the low molecular weight basic fraction (M1 ≈ 500–2,000 Da). The experiments on the kidney cell cultures of pigs and cattle have shown that at non-toxic concentrations (10–5 %) PHMBH can effectively stimulate (from 27 to 65 % increase) the proliferative activ- ity of eukaryotic cells and accelerate the formation of a monolayer of cells. The combinations of PHMGH with some essential oils of medicinal plants also show a good effect (from 52 to 95 % increase), and PHMBH shows a good effect with oil of pine for pig kidney cells (20 % increase) and oil of horsemint for cattle kidney cells (67 % increase). Conclusions. PHMGH and PHMBH can possibly be used in agricultural production not only as disinfectants or antiseptics, but also in wound healing. Although their toxicity is also significant to eukaryotic cells, yet they can possibly be used in veterinary medicine in low concentrations (0.005–0.5 %) for the treatment of wounds of various origin, including burns, in the composition of ointments, gels, bandages, or plasters, which we have presently in investigation.

DNA Damage and Oxidative Stress of Tobacco Smoke Condensate in Human Bladder Epithelial Cells.

Smoking is a major risk factor for bladder cancer (BC), with up to 50% of BC cases being attributed to smoking. There are 70 known carcinogens in tobacco smoke; however, the principal chemicals responsible for BC remain uncertain. The aromatic amines 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA) are implicated in BC pathogenesis of smokers on the basis of the elevated BC risk in factory workers exposed to these chemicals. However, 4-ABP and 2-NA only occur at several nanograms per cigarette and may be insufficient to induce BC. In contrast, other genotoxicants, including acrolein, occur at 1000-fold or higher levels in tobacco smoke. There is limited data on the toxicological effects of tobacco smoke in human bladder cells. We have assessed the cytotoxicity, oxidative stress, and DNA damage of tobacco smoke condensate (TSC) in human RT4 bladder cells. TSC was fractionated by liquid-liquid extraction into an acid-neutral fraction (NF), containing polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, phenols, and aldehydes, and a basic fraction (BF) containing aromatic amines, heterocyclic aromatic amines, and N-nitroso compounds. The TSC and NF induced a time- and concentration-dependent cytotoxicity associated with oxidative stress, lipid peroxide formation, glutathione (GSH) depletion, and apurinic/apyrimidinic (AP) site formation, while the BF showed weak effects. LC/MS-based metabolomic approaches showed that TSC and NF altered GSH biosynthesis pathways and induced more than 40 GSH conjugates. GSH conjugates of several hydroquinones were among the most abundant conjugates. RT4 cell treatment with synthetic hydroquinones and cresol mixtures at levels present in tobacco smoke accounted for most of the TSC-induced cytotoxicity and the AP sites formed. GSH conjugates of acrolein, methyl vinyl ketone, and crotonaldehyde levels also increased owing to TSC-induced oxidative stress. Thus, TSC is a potent toxicant and DNA-damaging agent, inducing deleterious effects in human bladder cells at concentrations of <1% of a cigarette in cell culture media.

Misconception on addition and subtraction of fractions in seventh-grade middle school students

As national and international assessments continue to show students struggle with rational concepts, which are seen as a major stumbling block for future career in STEM fields, we used the certainty of response index (CRI) as a method of analysis to investigate a group of 40 United Arab Emirates (UAE) seventh grade students’ understanding of basic fraction concepts. The types of errors and misconceptions displayed by students show that over 60% of all participants assumed that adding fractions procedurally is the same as adding whole numbers with many not being able to distinguish a numerator from a denominator. The results lead us to believe that the manner in which students were taught did not ensure the necessary transitional shift from learning whole numbers to learning rational numbers. Applying the theories of Dienes (1960) and Bruner (1966), we propose a method of teaching addition and subtraction of fractions that will allow students to build their own understanding of the rules using the graphing calculator as the medium for concept formation.

New cyclopeptide alkaloid of Condalia buxifolia and the absolute stereochemistry of Condaline A

During the course of a study of Condalia buxifolia (Rhamnaceae), one new cyclopeptide alkaloid condaline B (1), together with six known cyclopeptide alkaloids, condaline A (2), and the scutianines B (3), − D (4) and -E (5), frangulanine (6), and 3,4,28-tris-epi-scutianene N (7), were isolated from the rind bark of Condalia buxifolia. Their structures have been confirmed through spectroscopic analyses such as 1D and 2D NMR experiments. The absolute stereochemistry of condaline A (2), was elucidated by X-ray crystal structure determination of its HI salt. In addition, condaline B (1) was obtained synthetically through a structural transformation of condaline A. Meanwhile, the crude methanol extract, the basic ether fraction, and alkaloids 1–7 were tested against various strains of Gram-positive and Gram-negative bacteria and fungus, showing promising antimicrobial activity

Estimating textural fractions of the USDA using those of the International System: A quantile approach

In soil science, the two most frequently used classification systems for the soil particle size distribution are the schemes by the United States Department of Agriculture (USDA) and the so-called International System (IS), whose difference is the upper particle size limit of the silt fraction, namely, 0.02 mm for the IS and 0.05 mm for the USDA system. The existence of these and other systems creates a disparity that hinders and prevents the use and exchange of soil information worldwide. To solve this problem, it is necessary to devise methodologies for the conversion of textural fractions between the different classification systems. This work focuses on the estimation of the USDA silt fraction from the basic textural fractions (sand, silt and clay) in the IS. Five models are currently available for that purpose: the log-linear interpolation method, the Minasny-McBratney-Bristow regression formula, the Shirazi-Boersma-Johnson interpolation method, the Minasny-McBratney regression formula, and the Padarian-Minasny-McBratney regression formula. The accuracy of some of these methods has already been assessed, but in this work we develop a new methodology, based on a local quantile regression, which improves and enriches this evaluation, providing both the regions of the textural triangle where the predictions of the models are acceptable, and the regions where each model is most appropriate. The data used were taken from the publicly available National Cooperative Soil Survey Soil Characterization Database, from which more than 270,000 soil horizon samples were selected for having valid texture data. The analysis carried out concludes that the Padarian-Minasny-McBratney regression formula is the best model of those evaluated. In addition, the tool developed for the evaluation of the models becomes a new model that provides point estimates of the USDA silt fraction from the basic textural fractions in the IS, with further improvement, compared to the 5 models evaluated, as it also provides a prediction interval for those estimates.

Oral mucosal Cryoglobulin [ICD-10-CM Diagnostic Code D89.9 Cryoglobulin], Oral Mucosal Herd Immunity and the Immune Herd Plots among Periodontal Disease Patients

Forty five patients were diagnosed by specialist dentist of the team as periodontal disease patients. Basically they were found to be chronic periodontitis and chronic gingivitis. The study male and female patient groups [25 males and 20 females] were subjected to the detection of oral mucosal cryoglobulin and tempts to use cryoglobulin as a marker for oral mucosal herd immunity among these patients. Oral mucosal cyoprotein solutions were separated and characterized as oral mucosal cryoglobulin [ICD-10-CM Diagnostic code, D89.9 Cryglobulin]. Mucosal cryocrit percentages were ranged from one to seven percent. Oral mucosal cryoglobulin concentrations were ranged between 0.13 up to 2 mg/dl. In chronic periodontitis patients and 0.15 up to1.96 mg/dl.in chronic gingivitis patients. The individuals Mucosal herd immunity constitutes three basic immune fractions; low, moderate and high cryoglobulin responders. The immune herd plot types were matched as Gaussian distribution plot types. The findings of oral mucosal cryoglobulin among these patients in clinically indicative concentrations for the potential role may be played in the pathogenesis of chronic gingivitis and chronic periodontitis as it may cause precipitates in the local blood vessels of gum and periodotium.

국가산림자원조사 고정표본점 자료를 활용한 고사목의 탄소저장량 추정

The greenhouse gas reduction function of forests is crucial globally in ameliorating climate change. Varying research attempts to assess dead organic matter and carbon stock volume in soil have been conducted. The purpose of this study was to analyze changes in the occurrence of coarse woody debris (CWD) and related carbon stocks using data from the National Forest Inventory (NFI). To monitor changes in forest resources over time, this study used NFI data (2006-2020) that were collected from permanent sample plots every five years; 1,903 sample plots in which CWD occurred were analyzed at each time point and CWD volume was calculated based on tree stem volume. Carbon stocks of CWD were estimated by applying basic woody density and carbon fraction to CWD by tree type and tree decay level. The average volume of CWD decreased from 23.04 to 14.83 ㎥ ha<SUP>-1</SUP> and carbon stocks of CWD were also reduced from 3.36 to 1.86 ton C ha<SUP>-1</SUP>. This analysis estimated carbon stocks of CWD in forests nationwide and the results can be utilized to build a greenhouse gas inventory. Long-term monitoring and research are needed to identify the changing characteristics of CWD carbon storage. As carbon storage in forests is interconnected, monitoring and model development should include trees, CWD, forest floor litter, and soil carbon cycles. Furthermore, an analysis of the effect of anthropogenic activities on carbon cycles in future research would be useful.