Judul: Gambaran Spermatogenesis dan Superoksida Dismutase pada Testis Tikus Model Diabetes yang Diberi Ekstrak Etanol Biji Mahoni (Swietenia mahagoni Jacq.).
Abstrak: Diabetes mellitus (DM), a metabolic disease, is characterized by hyperglycemia. The aim of this study was to analyze the number of spermatogenic cells, the number of Leydig cells, and antioxidant Cu,Zn-SOD content in the testical tissues of experimental diabetic rats treated with ethanolic Swietenia mahagony seed extract. This study used 25 rats Sprague Dawley and the rats were divided into 5 groups; non DM group (K-), DM group (K+), DM group that was treated with ethanolic Swietenia mahagony seed extract (EM), DM group that was treated with acarbose 2 mg/kg body weight (KO), and non DM group that was treated with ethanolic Swietenia mahagony seed extract (KE). The dose of the extract was 500 mg/kg body weight. The treatments were done for 28 days. The testical tissues were subjected to tissue processing and stained using hematoxylin eosine and immunohistochemical technique. The results showed that ethanolic Swietenia mahagony Jacq. seed extract increased the number of spermatogenic cells, the number of Leydig cells, and antioxidant Cu,Zn-SOD content in the testical tissues of experimental DM rats.
Keyword: antioxidant, superoxide dismutase, Leydig cells, spermatogenesis, Swietenia mahagony

Judul: Gambaran Spermatogenesis, Sel Leydig, dan Superoksida Dismutase Pada Testis Tikus Diabetes yang Diberi Tepung Tempe
Abstrak: Diabetes melitus merupakan suatu penyakit yang beruhubungan dengan terganggunya pengaturan kadar gula dalam darah. Diabetes melitus ditandai dengan kondisi hiperglikemia dan menyebabkan tingginya kadar radikal bebas dalam tubuh. Antioksidan diperlukan untuk mengurangi radikal bebas. Selain antioksidan endogen, antioksidan juga ada yang berasal dari luar tubuh (antioksidan eksogen). Tempe adalah salah satu bahan pangan yang mengandung banyak antioksidan. Tujuan penelitian ini adalah menganalisis jumlah sel-sel spermatogenik, jumlah sel Leydig, dan kandungan antioksidan Copper, Zinc-Superoksida (Cu,Zn-SOD) pada jaringan testis tikus yang diberi tepung tempe. Penelitian ini menggunakan 12 ekor tikus jantan Sprague Dawley yang dibagi menjadi empat kelompok: kelompok tikus tidak diabetes yang diberi ransum standar (KN); kelompok tikus diabetes yang diberi ransum standar (KP); kelompok tikus diabetes yang diberi ransum tepung tempe kedelai (TB); dan kelompok tikus diabetes yang diberi ransum tepung tempe kecambah kedelai (TK). Perlakuan diberikan selama 28 hari. Jaringan testis disampling di akhir perlakuan, lalu diproses dengan metode standar embedding dengan parafin dan diwarnai dengan pewarnaan hematoksilin-eosin dan teknik imunohistokimia terhadap kandungan Cu,Zn-SOD. Pemberian ransum tepung tempe kedelai (TB) dan tepung tempe kecambah kedelai (TK) dapat mempertahankan jumlah sel spermatogenik, jumlah sel Leydig, dan kandungan antioksidan Cu,Zn-SOD pada jaringan testis tikus diabetes. Perlakuan protein tepung tempe kecambah kedelai (TK) memberikan hasil yang lebih baik dibandingkan perlakuan protein dari tepung tempe kedelai (TB) dalam mempertahankan jumlah sel spermatogenik, jumlah sel Leydig, dan kandungan antioksidan Cu,Zn-SOD pada jaringan testis tikus diabetes.
Keyword: Diabetes melitus, testis, superoksida dismutase, tepung tempe kedelai, tepung tempe kecambah kedelai

Judul: Which one use to overcome multicollinearity ? Ridge regression or principal component regression
Abstrak: In multiple linear regression the effect of nonorthogonality of the prediction vectors is to pull the least squares estimates of the regression coefficient away from the true coefficient that one is trying to estimate. Separating the effects of each factor of the regressors has been found to be difficult because of high correlation among independent variables. Although the multicollinearity problem has been recognized by many ways, ordinary least squares is still the main technique used in many fields, but the estimation of regression coefficient can present problems when the data vectors for the predictors are not orthogonal, or in this case are multicollinear. In using ordinary least squares, the regression coefficient may be unstable, too large in absolute value, and incorrect with respect to sign. Introduced biased estimation refer to unbiased one that measure the average closeness to the parameter being estimated corresponding to its mean square error (MSE). Ridge regression and principal component can produce better estimates by its own way than those given by ordinary least squares. It may well be preferred estimator since it will have larger probability of being close to true parameter value. Two of the biased regression methods, ridge regression and principal component regression will be applied into this research and discuss briefly for each of its properties. These methods have its particular idiosyncrasy. The biased regression methods attack the collinearity problem by computationally suppressing the effects of the collinearity. Ridge regression does this correctly by modifying the correlation matrix adding a biased constant driving through nonsingular matrix. Principal component regression attacks the problem by regressing Y on the important principal component and then parceling out the effect of the principal component variables to the original variables. Finally translated back the obtained variables into original variables yield the same sign and nearly the same coefficients for both methods.
Keyword: Regresssion analysis