Judul: Characteristics of Seaweed Salt Residue Sargassum polycystum and Coffee Dregs as Raw Materials for Body Scrubs
Abstrak: Kosmetik tersedia dalam berbagai sediaan, salah satunya yaitu dalam sediaan body scrub yang mengandung butiran kasar yang bersifat sebagai pengampelas (obrasiver). Pembuatan body scrub dari residu rumput laut Sargassum polycystum dapat ditambahkan dengan ampas kopi. Penelitian ini bertujuan untuk menentukan karakteristik residu garam rumput laut cokelat Sargassum polycystum dan ampas kopi serta menentukan pengaruh penambahan ampas kopi terhadap karakteristik body scrub berbahan baku residu garam rumput laut Sargassum polycystum 7%. Penambahan ampas kopi dengan konsentrasi (0; 1; 2; 3%) pada body scrub. Produk terpilih yaitu body scrub yang ditambah residu garam rumput Sargassum polycystum 7% dan ampas kopi 3% (SA 7:3). Nilai pH dari produk terpilih adalah 6,76 dan daya sebar pada 3,57 cm. Uji stabilitas emulsi menunjukkan bahwa krim dalam keadaan stabil. Aktivitas antioksidan dari produk terpilih dengan metode 1.1-diphenyl-2-picryl-hydrazyl (DPPH) adalah 55,54 ppm dan Cupric Ion Reducing Antioxidant Capacity (CUPRAC) 78,84 (µM/g). Hasil penelitian menunjukkan pada body scrub mempunyai kelembaban yang baik untuk kulit., Cosmetics are available in various preparations, one of which is a body scrub that contains coarse grains which act as a sandpaper (obrasiver). Make a body scrub from the residue of Sargassum polycystum seaweed can be added with coffee grounds. This study aims to determine the characteristics of the salt residue of Sargassum polycystum brown seaweed and coffee grounds and to determine the effect of the addition of coffee grounds on the characteristics of a body scrub made from 7% Sargassum polycystum seaweed salt residue. Addition of coffee grounds with a concentration (0; 1; 2; 3%) to the body scrub. The selected product was a body scrub with 7% Sargassum polycystum grass salt residue and 3% coffee grounds (SA 7:3). The pH value of the selected product was 6.76 and the dispersion was 3.57 cm. The emulsion stability test showed that the cream was in a stable state. The antioxidant activity of the selected product using the 1.1-diphenyl-2-picryl-hydrazyl (DPPH) method was 55.54 ppm and the Cupric Ion Reducing Antioxidant Capacity (CUPRAC) was 78.84 (µM/g). The results showed that body scrubs have good moisture for the skin.
Keyword: body scrub, coffee grounds, Sargassum polycystum

Judul: Characteristics of Body Scrub Sargassum sp. Seaweed Salt Residue with the Addition of Turmeric Rhizome Powder
Abstrak: Residu garam rumput laut Sargassum sp. dapat berperan sebagai scrub alami yang diharapkan mampu menggantikan mikroplastik polyethylene. Penambahan bubuk rimpang kunyit berfungsi untuk meningkatkan nilai fungsi sediaan body srub, seperti aktivitas antioksidannya. Penelitian ini bertujuan menentukan penambahan konsentrasi bubuk rimpang kunyit (Curcuma longa) terbaik pada sediaan body scrub residu garam rumput laut Sargassum sp. 7% dengan karakteristik yang sesuai. Sediaan body scrub terbuat dari campuran bahan fase minyak dan bahan fase air dengan penambahan residu garam rumput laut Sargassum sp. 7% dan bubuk rimpang kunyit 0,5%, 1%, dan 1,5%. Produk sediaan body scrub terpilih yaitu SK 7:0,5 (kombinasi residu garam rumput laut Sargassum sp. 7% dan bubuk rimpang kunyit 0,5%) dan telah sesuai dengan acuan yang ditetapkan, kecuali uji daya sebar. Sediaan body scrub SK 7:0,5 memiliki nilai pH 6,52, waktu lekat 1,54 detik, diameter sebar 3,33 cm, emulsi yang stabil, homogen, mampu meningkatkan kelembaban kulit, total fenol 464,52 ± 12,67 mg GAE/g, aktivitas antioksidan CUPRAC 1,20 ± 0,003 μg/mL asam askorbat/g sampel dan ABTS dengan nilai IC50 195,99 ± 1,30 μg/mL., Sargassum sp. seaweed salt residue acts as a natrual scrub that is expected to replace polyethylene microplastics. The addition of turmeric rhizome powder serves to increase the functional value of body scrub, such as antioxidant activity. The aim of this research was to determine the best concentration of addition turmeric rhizome powder (Curcuma longa) to body scrub Sargassum sp. 7% with the best characteristics. The body scrub was producted from mixing oil and water phase material with the addition of Sargassum sp. seaweed salt residue 7% and turmeric rhizome powder 0.5%, 1%, and 1.5%. The body scrub product selected was SK 7:0.5 (a combination of Sargassum sp. seaweed salt residue 7% and turmeric rhizome powder 0.5%) and was in accordance with the established standards, except for spreadability test. The body scrub SK 7:0.5 had pH value 6.52, adhesion time 1.54 seconds, spread diameter 3.33 cm, stable emulsion, homogeneous, able to increase skin moisture, total phenol 464.52 ± 12.67 mg GAE /g, antioxidant activity of CUPRAC 1.20 ± 0.003 g/mL ascorbic acid/g sample and ABTS with IC50 value of 195.99 ± 1.30 g/mL.
Keyword: Antioxidant, microplastic, moisture, scrub

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model