This study aims to: (1) develop an interactive multimedia with virtual laboratory in excretory system for senior high school students, (2) determine the eligibility of digital multimedia of excretory system, (3) determine the effectiveness of digital learning using interactive multimedia to improve students' achievement and activities using the excretory system. This research was conducted at Senior High School 1 Jepon, Blora, Indonesia for 2 months. The research approach was educational research and development including: (1)research and information collecting, (2) planning, (3) developing the preliminary form of the intended product, (4) preliminary field testing and validation of media by experts, (5) main product revision, (6)field testing, (7)operational product revision, (8) operational field testing, (9) final product revision, and (10) dissemination and implementation. The result is as follows: 1) the excretion system of virtual lab needs to be improved because of the inavailability of tools and limited materials, obselete school lab, expensive tools and lab materials, and crowded scheduling of laboratory uses; 2) digital multimedia of the excretory system with virtual lab is very eligible with outstanding criteria based on expert validation and field testing result; 3) digital learning using interactive multimedia improves students' achievement and activities, (tnumber of students who achieve the active criteria is 90.63%).
The implementation of the kurikulum 2013 requires of innovative and creative learning with the integration of technology in learning process. Teachers should be creative in finding and gathering learning resources, as well as making teaching materials needed in learning that can help students in learning to achieve goals in the curriculum. So it is necessary to develop learning media based on My Android Biology App in schools in learning biology. Especially in the food digestive system material can be motivate the student and the result of learning. The aim of this study is (1) to analyze the validity of the My Biology App according to media experts and material experts, (2) to analyze the feasibility of the my biology app according to teacher and student responses, (3) to analyze student learning motivation and (4) to analyze the result of learning at student. The method of research is Research and Development (R & D). Pre-Posttest Control Group is the research design. The results of the validation from media experts and material experts indicate that the learning media My Biology App is very valid. It appears in teacher responses with an average of 97.62 and student responses with an average of 108 with a percentage of 90% suitable for use in learning activities. The effectiveness is determined from the motivation data and student learning outcomes. 63% of students are highly motivated and 37% are motivated. The results of the posttest in the experimental class with an average of 86.96 greater than the posttest in the control class with an average of 83.25. In addition, the n-gain in the experimental class 0.74 is greater than the control class with an n-gain of 0.70. It can be concluded based on the results of research that the learning media My Biology App can increase motivation and student learning outcomes in the food digestive system material.
Two known compounds, namely stigmast-4-en-6β-ol-3-one (1) and p-hydroxybenzoic acid (2) are firstly reported from stems of E. elatior. Isolation were carried out by chromatography technique including Thin Layer Chromatrography (TLC), vacuum liquid chromatography (VLC) and radial chromatography (RC) with silica gel as adsorbent and mixture of solvents as eluen. Structure of isolated compounds were determined by spectroscopy methods i.e. FTIR, 1H and 13C NMR and also by comparison the spectroscopies data with the same data from references. Biological activities of isolated compounds evaluated against some bacteria consist of Bacillus subtilis FNCC 0060, Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853, Salmonella enterica ATCC 14028, Staphylococcus aureus ATCC 25923, dan Streptococcus mutans ATCC 25175 and also against DPPH (2,2-diphenil 1-pichylhydazyl) radical as antiradical scavenger activity. The result showed that generally, antibacterial potency those samples i.e. methanol extract, stigmast-4-en-6β-ol-3-one and p-hydroxybenzoic acid less active than positive control (chloramphenicol). Individually, antibacterial activity of p-hydroxybenzoic acid > methanol extract > stigmast-4-en-6 β-ol-3-one. In addition, p-hydroxybenzoic acid is the most active against S. mutans. Radical scavenger activity of tested samples is less active than than positive control (ascorbic acid). Furthermore, the radical scavenger potency of p-hydroxybenzoic acid > methanol extract > stigmast-4-en-6 β-ol-3-one.
Escalation in blood lead level may decrease sperm quality. Chelating agent, such as chitosan, is known to reduce the detrimental effects from lead exposure. This research aims to analyze the effect of chitosan on sperm quality of lead acetate-induced rats. 30 rats were divided into six groups. All treatment groups, aside from control group, were induced by 175 mg/kg weight of lead acetate. Positive control group was treated with Ca2EDTA, while negative control group was only treated with lead acetate. Treatment group 1, 2, and 3 were treated with chitosan in gradual dose; 64, 32, and 16 mg/kg weight respectively. On the 31st day, the sperm quality was analyzed and the rats were terminated. Statistical result showed that positive control group and treatment groups had no significant difference from control group but was significantly different from negative control group. Research parameters, which were sperm count, motility of progressive sperm, immotile sperm, and normal sperm, were significantly different among the all treatment groups. However, another research parameter, which were nonprogressive sperm motility and sperm viability were not significantly different. Treatment group 1 was not different significantly from control and positive control groups. To sum up, chitosan improves the sperm quality of lead acetate-induced rats.
Chitosan is a potential natural blood lead chelating agent. In order to improve its chelating capability, the solubility of chitosan must be enhanced. It is an essential property which is also closely related to molecular weight and viscosity. One of the most renowned and effective methods to reduce the molecular weight and viscosity of a certain particle is irradiation. This research aims to examine the effect of Gamma 60Co irradiation upon molecular weight and viscosity of chitosan. 80 mesh chitosan was irradiated using Gamma 60Co with different doses (0, 50, 100, and 150 kGy). This process was carried out using gamma irradiator in the Centre of Isotopes and Radiation Application at BATAN (National Nuclear Energy Agency). Viscosity and molecular weight measurements were conducted using the viscosimetric method in the chemistry laboratory of FMIPA UNNES, while molecular weight was calculated using the Mark-Houwink equation. Results showed that the specific viscosity of chitosan decreased after the irradiation process from the initial specific viscosity of 4.98 η (0 kGy dose) to 3.28 η (50 kGy), 2.87 η (100 kGy), and 2.09 η (150 kGy). A similar trend was also found in the molecular weight of chitosan from the initial molecular weight of 2.10×105 kDa (0 kGy dose) to 1.25×105 kDa (50 kGy), 1.04×105 kDa (100 kGy), and 5.72 × 104 kDa (150 kGy). It was concluded that Gamma Co60 irradiation decreases the viscosity and molecular weight of chitosan by the effective dose of 150 kGy.
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