Recently Published
Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Most Viewed
Journal article

## Teaching Media Development of Mathematic in the Materials Trigonometry Sum and Two Angles Difference by Using Gui Matlab

. The aim of this research is to develop teaching media for mathematics specifically for materials on trigonometry using GUI Matlab. This media can be used as teaching and learning aid for students at senior high school, grade XI in the first semester. This learning media consists of instructions on how to use the media, learning materials, exercises and profile. The trigonometry materials which are discussed in this learning media consist of the sum and difference of two angles. The limitation on the angles that can be used are special angles in the interval -360o £ a,b £ 360o. The special angles are 0o, ±30o, ±45o, ±60o, ±90o, ±120o, ±135o, ±150o, ±180o, ±210o, ±225o, ±240o, ±270o, ±300o, ±315o, ±330o, and ±360o. The trigonometry functions such as sinus, cosine and as well as the operation addition (+) and subtraction (-) can be selected by hitting the appropriate button. Within each step, there is a check button and a next button to check the input true or false. If the value that entered incorrectly then the next step will not displayed and warning box will appear to report the location of error. Users have to fix the error in order to continue to the next step.
Journal article

## Isolation of Antioxidant Compounds of Methanol Extract of Nutmeg Leaves (Myristica Fragrans Houtt)

.The antioxidant activity from methanol extract of nutmeg leaves (Myristica fragrans Houtt) was performed using 2,2-diphenyl-1-picrylhydrazil (DPPH). Antioxidant assay using DPPH of the methanol extract at a concentration of 25 ppm, 50 ppm and 100 ppm, showed high antioxidant activity with IC50 = 36.31 ppm and Vitamin C showed antioxidant activity with IC50 = 3.657 ppm. The methanol extract of nutmeg leaves were partitioned with chloroform to obtain chloroform extract of the leaves with IC50 = 28.30 ppm. isolation of the active compounds from the chloroform extract of the nutmeg leaf using column chromatography yielded 6 mix fractions MFMD 1, MFMD 2, MFMD 3, MFMD 4, MFMD 5 and MFMD 6. The test results of antioxidant activity in very strong category is fractions MFMD 4, MFMD 3, MFMD 2, MFMD 6 and MFMD 5 with IC50 of each are 26.590 ppm, 27.239 ppm, 29.639 ppm, 39.766 ppm and 55.436 ppm, while antioxidant activity in a weak catagory is fraction MFMD 1 with IC50 is 126.270 ppm. This shows that the fraction of the leaf has a better inhibitory activity, because some of the active compound contained in the fraction can synergize in inhibiting free radicals, so that the IC50 value of the fraction is stronger than the extract.
Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

## Inhibition Test of Methanol Extract From Soursop Leaf (Annona Muricata Linn.) Against Streptococcus Mutans Bacteria*

Suggested For You
Journal article

## Character's Selection of Leaf Morphology in Some Families (Tree Habit) in Sumatra Region for Species Identification

Identification is a basic activity and one of primary objective on systematic. For plant biodiversity studies,it was the first steps that researcher performed before studying any topics in the research area. Unfortunately, species identification is usually a time consuming activity. One of the main objectives of this study was to obtain a set of leaf morphology characters that were useful and efficient enough for species identification, especially on the tree habits group in order to reduce time consuming for the identification species. All of the leaf morphology characters were selected by correlation coefficient and separation coefficient values. Besides of that, the stability, simplicity and validity of the characters were also part of concern. The characters that had high value of separation coefficient and low value of correlation coefficient would be added one by one as in their rank, until the value of the combination separation coefficient was equal to 1 (100%). The result of this study suggested that 30 from 92 characters of leaf morphology were recommended as a set of characters that useful and efficient enough for species identification.
Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article

Journal article