Panasenko A.I., Buryak V.P., Samura T.A., Timoshik J.V., Gotsulya A.S., Postol N.A., Kulish S.N.

Zaporozhye State Medical University,

National University of life and Environmental Sciences of Ukraine

TOXICOLOGICAL CHEMISTRY. NEW TEACHING STRATEGIES TO IMPROVE TEACHING AND LEARNING

Ukrainian medical and pharmaceutical universities have been undergoing reform over the last fifteen years. However the teaching methods have not changed sufficient to satisfy the requirements of the education system reform. Traditional teaching approaches still dominate the campuses of universities in Ukraine. Teachers give formal lectures to transmit knowledge. Students receive in passively and are expected to reproduce it accurately in examinations. All students are different because each has a unique experience of the world. Giving the same piece of information to all students at the same time may only work for those whose schema can assimilate it [10]. Not all students are at the same level of understanding at the same time. This kind of teaching approach mostly leads to a surface level learning and an over-dependence on the lectures.

In Ukraine society, there are same new trends and changes in education including a movement from a " teacher-centred approach" to a "student-centred approach" and a recognition that, wherever possible student must be active participants in the learning process in order to promote deep level processing of knowledge [4].

A research study on students knowledge retention showed that students usually retain 10% of what they read; 26% of what they hear; 30% of what they see; 50% of what they see and hear; 70% of what they say; 90% of something they say while they are doing a task [5] . So the traditional approach to teaching science must be improved. We plan to introduce some new teaching strategies we have studied at the National University of Pharmaceutical (Kharkiv) and Zaporozhye State Medical University to improve the traditional teaching approach and increase teaching quality. However these strategies are not replacements for the traditional teaching approach. Ukrainian people have their own characteristics and distinguishing qualities and we believe that it is not right to abandon the traditional teaching approach. The traditional teaching approach can be adapted modified and improved by integrating a range of contemporary teaching approaches.

Toxicological chemistry is a course for the eighth and nineteen semester of the five-year education on the pharmaceutical high schools. Toxicological chemistry contains 30 hours of lectures, 70 hours of experiments and 11 hours of tutorials covering two semesters. The traditional teaching approach is a teacher-centered teaching model. According to a survey, in a traditional course student only listen and they can retain 28% of the knowledge the teacher presents [2]. Student learns passively and employs surface level processing. They are over-dependent on information selection and provide for them by their lecturers. But it is difficult to abandon the traditional teaching approach completely, because Ukraine has a very large population of student. The traditional beaching approach requires fewer teachers and teaches more students. So it is necessary to improve the traditional teaching approach step-by-step. The main goals of the improvements to the course are to enable students: to master toxicological chemistry principles and technology more deeply using toxicological chemistry knowledge to analyze and solve chemistry-related problems; and to develop the ability of independent thinking when we return to Ukraine we would like to introduce some new teaching strategies such as student-centered teaching problem lased learning, case studies, and group learning to my class to improve my teaching methods and increase my teaching quality.

"chalk and talk" is the predominant teaching style in the traditional teaching approach. Student-centered teaching is based on the hypothesis that students benefit by being given the freedom to study and search for solutions based on their personal interests [8]. Students are allowed to discuss and work together on the problem, to explore different paths for solutions without pressure in work shop tutorials. The responsibility for learning is with the students [1]. In order to overcome some shortcomings of traditional teaching approaches such as spoon-feeding and over-dependence on the lecturer, student-centered teaching is a useful method to improve traditional course teaching and adapt to the changes and trend in teaching theories and practice. The results of contemporary research in education theory have shown how students learn and how teachers teach students more effectively. This approach can give students flexibility, self-confidence, and social skills.

In student-centred teaching, the teacher teaches only what he or she considers important and difficult it the lecture. The responsibility of the teacher is not only to deliver skills and provide a conceptual map of the subject, but also to motivate students to be more active adaptable, confident, creative, cooperative and inductive in their thinking. The teacher must help students make the transition from passive listeners to active participants, changing from a superficial to a deep learning approach developing the students’ abilities and skills for lifelong learning. We should teach them "fishing" no give them "fish". Students need to move from passive to active learning and from dependence to independence.

Problem based learning (PBL) is one of the most exciting and powerful educational options that has appeared in the last 17 years [9]. PBL is a learning environment in which the problem drives the learning. PBL begins with tackling a relevant problem that usually covers most of the course knowledge. In PBL the problem may not be solvable, but students can learn much by engaging in the process. Students themselves decide what they need to learn by engagement in the problem solving. Of course lectures still retain their importance for course learning. But the function is changed, switching from transmission of knowledge to a situation where teachers find out common difficulties in the problem solving process and give support via lectures. So PBL is a strategy for encouraging critical thinking, cooperative learning, and enhancing problem solving skill through resolving real-world problems.

The main features of this strategy (PBL) are: relevant problems, creating a need to know; integration of academic and professional knowledge; and interactive and cooperative learning.

The following is an example for PBL lectures: Suppose a person treated in a toxic gas that contains heavy metals such as mercury. The person will die if an appropriate medicine cannot be synthesized. The question is: how can we synthesize this medicine?

In order to solve the problem, students must learn the following aspects of toxicological chemistry:

- metallic organic poison;

- alcohol R-OH and R-SH;

- organic halogenides; and

- SN Reactions

After group discussions, finding the relevant knowledge and independent thinking, students may find a path like that illustrated in Figure I to synthesize the medicine.

Of course, the students may be unable to find a path to synthesize the antidote, but they can learn a great deal of chemical knowledge by engaging in the problem solving process.

CH₂-CH-CH₂ CH₂-CH-CH₂

S_N Reaction Hg²⁺ CH₂-CH-CH₂

OH OH OH SH SH SH

OH S S

Hg

Figure I possible pathway for synthesis of antidote
Case studies are different from PBL. They give real and complete stories with messages and questions, and teach through those stories. The case usually has both academic significance and social application. A good case study should be interesting, relevant, motivating, case study should be interesting, relevant, motivating, integrating many disciplines and related to the real world.
Case studies enable students to understand the application of toxicological chemistry to real world problems, to trace commercial innovations of well-known products from conception or an idea in the research toxicological laboratory to commercialization and to realize the influence of toxicological chemistry on our environment. We can also use case studies to help students to: build analytical and toxicological skills, develop problem-solving skills, decision-making skills, judgment skills, critical thinking skills, and communication skills; and learn how to deal with real-life problems.

In a case study the teacher guides students thought the maze of the case discussion by questioning, demonstrating, and highlighting the main points or issues. The students will be given background material related to the case, to read, think about, and discuss. Then teacher will give a mini-lecture on the background material to explain the relevant knowledge. The case background material and mini-lecture direct students to search for related materials and information form a concept map relevant to the case study. After that, students can understand the generation of the problem and determine the methods to solve the case. At the same time, there is an opportunity for teachers to ask students some relevant questions to stimulate their thinking and to enable them to discover for themselves the route to a possible solution or resolution. It is a very useful way to train their academic and critical thinking abilities.

The following is an example of a case study lecture: During the Second World War, the Fascist Army had a chemical weapon named Toxic Gas that contained heavy metals such as mercury (Hg). The chemical weapon was responsible for the deaths of thousands of Allied soldiers. The Allied Army was in danger. At this time, an English scientist focused his research work on the problem. Several weeks later, he synthesized a medicine named BAL (British anti-lewisite) to deal with the German chemical weapon. Thousands of lives were saved. Finally, the Allies won the war.

Toxicological chemistry is an experimental science. The laboratory is an ideal environment for both active and cooperative learning.

Active engagement in laboratory exercises promotes a thorough understanding of the concept described in lectures. A further enhancement of the laboratory experience can be gained by encouraging students to interact with each other during the discovery process. Experiments or laboratory work are very important for students not only for understanding toxicological chemistry knowledge but also for increasing the students ability to resolve problems.

Many of the traditional experiments can also be improved by using teamwork learning or a group learning approach in which students work collaboratively in the development of methods to obtain, apply, and understand information. The benefits associated with teamwork learning include improving proficiency in critical reasoning abilities and the acquisition of communication and inter-personal skills. It is planned to implement an active teamwork learning strategy in our toxicological chemistry laboratory.

In the teamwork learning format, students will be randomly assigned to group membership will be maintained throughout two semesters. Each week, the teacher will assign one person in each group to serve as group leader. The group leader has five major responsibilities: present pre-laboratory lectures; assign tasks; answer questions, submit group assignments; and assess group members. The group members responsibilities are to carry out the experiment(s), to contribute to written assignments and to assess the group leader individually. At the end of each experiment the students will participate in peer assessment. Group members assess the performance of the group leader and the group leader assesses each group member. For each experiment, students will also be required to complete written assignments as a group. Laboratory worksheets will contain five to ben questions related to the theoretical aspects of the experiment, experimental design, and setup. These will be collected one week after the experiment is completed. Worksheets generally require 1-2 hours of time outside of the laboratory to complete. Each group will require one notebook.

The teachers are still very important in a teamwork learning approach. Their duties are to ensure laboratory safety, to provide material and equipment for experiments, to assign group leaders, to assist group leaders in answering conceptual and technical questions of students, to supervise group activities, to assess group written assignments and to evaluate each group’s laboratory techniques.

In traditional teaching approaches students to experiments without understanding why they are using the apparatus provided for them or understanding many of the experimental steps. The teamwork learning format has a definite advantage in overcoming the weakness. The teamwork learning laboratory will be more focused on research work and designing laboratory activities and requires more collaboration between students and the development of teamwork. Teamwork learning methods also require students to have more imagination, more planning and to accept more challenging tasks. It places more emphasis on active learning and extra skills development. Before the laboratory session, students need to plan and design the detailed laboratory steps. During the laboratory session they need to check their plan and design and revise the laboratory project. After the laboratory sessions, they need to analyze the data and experimental phenomena and write the experiment reports [3].

Encouraging students to become deeply involved in the laboratory work and develop their skills are the main purposes of the new teaching strategy.

A new teaching strategy needs a new assessment procedure [6], Assessment methods profoundly influence learning [7]. In order to encourage active learning and meet the requirements of the new teaching strategy, I will use a combined assessment in the Toxicological chemistry course. The final mark will consist of 5 parts: a formal written examination which will be worth 50% questions which will be worth 10%; assignments which will be worth 10%; laboratory performance and reports which will be worth 15%; and a mini-presentation which will be worth 15%.

CONCLUSION

By improving the traditional teaching approach, we expect to achieve the following:

- assist in the reform of the education system:

- increase the student’s motivation;

- increase students interest in learning toxicological chemistry;

- improve the quality of teaching;

- emphasized that the responsibility for learning in the learner's, not the teacher's;

- develop some important abilities and skills in students such as problem solving skills, communication skills, critical thinking abilities, creative abilities, lifelong learning abilities.

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