Seeking the right balance between three teaching approaches: a quasi-experimental study in the context of learning about thermal phenomena

In this study, we investigated which teaching approach may be optimal to facilitate learning about thermal phenomena in primary school. Concretely, we conducted a pretest-posttest quasi-experiment that included 45 eighth-grade students divided into three groups. In the first group (a non-interactive teacher-centered approach), the teacher gave an experiment-based lecture on converting thermal energy into mechanical work. In the second group (a teacher-centered interactive approach), the teacher gave the same experiments-based lecture, but interacted much more with the students and encouraged them to think about the demonstrations. Finally, in the third group, the student-centered interactive approach was applied. The results of the ANCOVA showed that the three teaching approaches were equally effective in developing students’ understanding of thermal phenomena. However, closer analyses showed that students who learned from the teacher-centered interactive approach significantly outperformed their peers when it came to understanding basic thermal concepts approach, students worked in small groups to conduct the same experiments and “discover” the same relationships that the teacher had introduced in the previous one.

Smoking effect on the cadmium and zinc concentration in smokers and nonsmokers

Studies have shown that cigarette smoking affects the accumulation of some heavy metals in certain tissues and metabolism of essential elements. The aim of the study was to determine the differences in the concentrations of cadmium in the blood and urine and zinc in the urine of smokers and ex-smokers in relation to non-smokers, and to determine the possible influence of cadmium concentration on zinc excretion as an essential element. The study included 106 subjects. Subjects were regular smokers (n=51), ex-smokers (n=38) and non-smokers (n=17). Atomic absorption spectrophotometry (AAS) with an electrothermal atomizer was used to determine cadmium. Zinc was determined by AAS with a flame atomizer. There was a significant difference in the values of cadmium in the blood between the groups: smokers and non-smokers (p<0.001), smokers and ex-smokers (p <0.001), and between ex-smokers and non-smokers (p = 0.045). There is a significant positive and strong correlation in the level of zinc and cadmium in urine per gram of creatinine, and as the level of cadmium increases, the level of zinc also increases (rho=0.781; p=0.001). The data indicate that cigarette smoking has been shown to be a factor that can increase cadmium levels to an extent that will significantly increase zinc excretion, or its increased loss.

Occurrence of the heavy metals and PCBs in Accumulation Lake Modrac

The accumulation Lake Modrac is a particularly important source of drinking water for inhabitants of the Tuzla region and few local settlements. The most significant point sources of organic contaminants in the accumulation Lake Modrac are waste water from households and industry. In this area, most of the settlements have neither sewage systems nor facilities for waste water treatment. Other potential point sources of pollutants are industrial plants. The most prominent are coal mines (Banovići and Đurđevik), metal and wood industry, plant for plastic production, and oil and oil derivatives warehouse. Few previously conducted surveys in the region showed the presence of the persistent organic pollutants and heavy metals in large extent. The objective of this study was to conduct a water quality survey targeting selected inorganic (Cd, Cr, Cu, Hg, Ni, Pb and As) and organic pollutants in the accumulation Lake Modrac in Bosnia and Herzegovina. The content of polychlorinated biphenyls (PCBs) determined with ELISA test, ranging from 3.23 to 6.19 µg/L (sum of 7PCBs).The most abundant metals (analyzed by graphite furnace AAS and mercury analyzer) at all five sampling locations were Pb (6.79-36.58 µg/L); Ni (5.81-10.43 µg/L) and Hg (1.08-6.10 µg/L).

Serum levels of non-enzymatic antioxidants in female dementia patients with respect to the degree of cognitive impairment

The aim of this study was to investigate the correlation between the severity of cognitive impairment in Alzheimer’s disease (AD) and vascular dementia (VD) and the serum antioxidant status of uric acid (UA), albumin (ALB) and bilirubin (BIL) in female patients. The cross-sectional study included 90 subjects, aged ≥65, divided into three groups: 30 patients with AD, 30 patients with VD and 30 control subjects. For cognitive assessment, all participants underwent the Montreal Cognitive Assessment (MoCA). Serum concentrations of ALB, UA and BIL were determined spectrophotometrically. The AD patients had a significant decrease of UA and increase of serum BIL. Upon stratification according to the degree of cognitive impairment, lower UA concentrations were found in patients with severe cognitive impairment, whereas increased BIL was found in patients with moderate cognitive impairment. Patients with VD were characterized by hypoalbuminemia and upon stratification this finding was evident among patients with severe cognitive impairment. The MoCA score correlated positively with BIL in AD patients. The obtained data supports the protective role of serum antioxidants in the pathogenesis of dementia. Further on, we suggest further longitudinal research to confirm the combined use of these parameters as potential biomarkers in AD and VD.

The Content of Essential and Toxic Metals in the Hair of Children with Autistic Spectrum Disorders

The aim of this study was to assess the possible relationship between the content of essential and toxic metals in the hair samples with the etiology of autism spectrum disorder (ASD) in children from Bosnia and Herzegovina. Taking into account the age and gender of the child, in the study and control group, the samples were divided into three subgroups (1-5 years; 6-9 years; 10-14 years). Altered profiles of the values of the Cu, Fe, Mn, Zn, Cd, Co, Cr, Ni, Pb in the study group were observed in comparison with the control group children with typical neuromotor development. Higher values of toxic metal concentrations (Co, Ni, Cd, Pb) were found in boys, compared to the girls in the study group. The content of Pb in the study group was higher in all three ages compared to their controls, with the difference being especially pronounced in the age group 1-5 years (6.64 mg/kg; 1.89 mg/kg). A strong correlation between the content of Pb and Cd (0.93) was confirmed. Lower values of Cr concentration and higher of Ni, Cu and Fe were recorded in the study group. Statistically significant differences (p<0.05) were found in Zn concentrations (6-9 years; 10 -14 years) between the control and study groups. The findings help highlight the role of heavy metals as environmental factors in the etiology of ASD.

Determination of Sulfites in Fruit Juices and Meals for Infants and Toddlers

Plants possess various intrinsic mechanisms necessary to accumulate and either sequester or detoxify soil contaminants, including radionuclides. The aim of this study was to determine the bioconcentration factor of two fast growing plants Salvia offlicinalis L. (sage) and Ocimum basillicum L. (basil) that were cultivated in pH neutral soils artificially contaminated with three different concentrations of uranium (211, 352 and 470 mg/kg). The efficiency of citric acid was evaluated with respect to the enhancement of the phytoextraction process. The results showed that the bioconcentration factor did not differ significantly between the selected species (0.01 - 0.03). Citric acid was added in doses (50 mL, 30 mM) until the first effects of uranium phytotoxicity appeared. After four doses of citric acid, the bioconcentration factor reached 0.05 for both plants. The increase of uranium content taken up by the respective plants was more pronounced. Thus, the uranium content of sage grown in contaminated soil (470 mg/kg) increased from 6.03 to 21.28 mg/kg in citric acid-treated soil. The data obtained confirmed the efficiency of citric acid in enhancing phytoextraction of uranium and further suggest that even plants of a rather small biomass can be useful in phytoremediation given the appropriate treatment through induced phytoextraction with appropriate chemical agents.

The Determination of Total Serum Bilirubin Concentration in Type 2 Diabetes patients

Bilirubin represent a natural end-product of heme metabolism and is used as as a marker in diagnosis off hepatobiliary diseases. Recent studies demonstrated that serum bilirubin levels are related to the risk of Type 2 diabetes mellitus (T2D) development and subsequent complications. The aim of this study was to analyzed serum total bilirubin concentrations and its relationship with biochemical and clinical characteristics in T2D patients. Total of 109 participants were included in this study, 54 controls and 55 diabetic patients, both gender, while ages ranged from 35 to 70 years. Biochemical parameters were analyzed by standard IFCC methods while serum total bilirubin concentrations was determined by the method of Jendrassik/Gróf. All analyses and measurements were provided by using the chemical analyzer VITROS 350. Results showed a significant difference in concentrations of glucose, glycated hemoglobin (HbA1c), lipid profile (total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol) and bilirubin between T2D patients and controls (p<0.05). Also, significant association was found between bilirubin and glucose concentrations in two investigated populations (p<0.05). It appears that elevated concentration of bilirubin and biochemical characteristics are associated with the progression development of Type 2 diabetes and its related vascular complications. Therefore, total serum bilirubin concentrations could be used as potential T2D biomarker and therefore, as new therapeutic target.

Relationship between platelet indices and lipid status in chronic hookah consumption

Hookah smoking is a growing trend, both in the world and in Bosnia and Herzegovina. The aim of this study was to determine the value of platelet indices in hookah smokers and find out associations with lipid profile. Cross-sectional study included 60 students (30 chronic hookah smokers and 30 non-smokers). The complete blood count (erythrocytes, leukocytes, platelets, hemoglobin, hematocrit, erythrocyte and platelet indices), lipid parameters (total cholesterol, triglycerides, LDL-C, HDL-C) were determined. The platelet count, mean platelet volume and MPV/Platelets ratio were statistically significantly higher in chronic hookah consumers in the student population than in the control group (p <0.001). In addition, platelet count was in significant positive correlation with values of total cholesterol, LDL-C and negative correlation with value of HDL-C, while there was a significant negative correlation between mean platelets volume, and MPV/Platelets ratio with HDL cholesterol levels in chronic hookah smokers (p <0.05). These findings suggest that chronic hookah consumption could be associated with the development of atherosclerotic changes in blood vessels, which could lead to the development of long-term consequences on the cardiovascular system's function.

Peroxidase activity of hemoglobin and heme destruction in the presence of hydrogen peroxide and CT-DNA

The aim of this study was to investigate the peroxidase activity of Hb with different concentrations of hydrogen peroxide and compare it with hypochlorous acid effect on Hb. Hypochlorous acid at higher concentrations decomposed Hb and heme, releasing fee iron ion from the metal center. High concentrations of hydrogen peroxide switched the peroxidase activity of Hb towards the partial Hb and heme destruction. Heme alone was degraded showing that the Hb conformation and protein environment protects Hb from the distraction in the presence of highly increased hydrogen peroxide concentration that occurs as a result of oxidative stress. In the presence of CT-DNA acted inhibition of the peroxidase activity of Hb was observed signaling inhibited hydrogen peroxide consumption.