Judul: Tingkat Toksisitas dan Uji Antibakteri Pada Daun Avicennia marina di TWA Angke
Abstrak: Avicennia marina merupakan salah satu jenis mangrove yang mempunyai kandungan beberapa senyawa metabolit sekunder. Metabolit sekunder dari daun mangrove A. marina memiliki aktivitas sebagai antibakterial terhadap bakteri patogen. Senyawa metabolit sekunder berperan sebagai sitotoksik. Sitotoksik adalah suatu senyawa yang bersifat toksik terhadap sel. Lamanya paparan zat toksik berhubungan erat dengan efek toksik yang ditimbulkan, sehingga perlu dilakukan uji toksisitas terhadap A. marina untuk mengamati aktivitas farmakologinya setelah terpapar oleh suatu senyawa dalam waktu singkat dan dosis tertentu. Daun A. marina yang diambil dari 2 lokasi dalam TWA Angke dikeringkan menjadi simplisia yang kemudian diekstraksi dengan pelarut air agar sesuai dengan kearifan lokal. Pengujian toksisitas ekstrak simplisia dengan metode Brine Shrimp Lethality Test (BSLT) terhadap Artemia salina nauplii dan pengujian antibakteri terhadap Escherichia coli, Bacillus subtilis, dan Pseudomonas sp. pH perairan dengan nilai 7.5 - 7.6 dan 7.5-7.9 termasuk nilai optimal untuk produktivitas biota dengan nilai potensial redoks sedimen 69.3mV dan -39.6mV yang menunjukan kondisi oksidatif dan reduktif pada sedimen masing-masing stasiun. LC50 cenderung muncul pada daun muda dibandingkan daun tua. Tidak ada daya hambat oleh daun A. marina terhadap Pseudomonas sp. Daya hambat dengan nilai 1mm, 2.67mm,7.33mm terhadap E. coli, 6.33mm terhadap B. subtilis masuk dalam kategori rendah hingga sedang yang muncul pada daun tua A. marina., Avicennia marina is one of the mangrove species that contain secondary metabolite compounds. Secondary metabolites from A. marina leaves have antibacterial activity towards pathogens. Secondary metabolite compounds act as cytotoxins. Cytotoxin is a certain compound that tends to be toxic to cells. The duration of exposure to toxic substances is closely related to the toxic effect that it shows; thus toxicity test needs to be done toward A. marina to observe the pharmacology activity after exposure to certain substances at a certain duration and dosage. Dried A. marina leaves as simplicia then extracted with water as a solvent to fit local medicinal wisdom. Toxicity test of simplicia extract with Brine Shrimp Lethality Test (BSLT) towards Artemia salina nauplii and antibacterial test towards Escherichia coli, Bacillus subtilis, and Pseudomonas sp. pH of water with value 7.5 - 7.6 and 7.5-7.9 are considered optimal for biota productivity with potential redox of sediment 69.3mV and -39.6mV that show oxidative and reductive state of sediment on each station. LC50 tends to appear on young leaves rather than old leaves. There’s no inhibition by A. marina towards Pseudomonas sp. Inhibition with values 1mm, 2.67mm,7.33mm towards E. coli, and 6.33mm towards B. subtilis are considered in the low to medium category that appears on old leaves of A. marina.
Keyword: Aktivitas Antibakteri, Avicennia marina, Toksisitas

Judul: Meta-analysis Effect of Solvent Type, Part, and Origin of Avicennia marina Mangroves on the Antibacterial Activity
Abstrak: Penelitian mengenai aktivitas antibakteri Avicennia marina telah banyak dilakukan selama 10 tahun terakhir. Berbagai penelitian tersebut menggunakan jenis pelarut, bagian, dan asal mangrove yang bervariasi sehingga memberikan kesimpulan yang beragam terhadap aktivitas antibakterinya. Meta-analisis merupakan penelitian yang menggunakan hasil penelitian yang sejenis dan mengambil kesimpulan berdasarkan hasil analisis. Penelitian ini bertujuan untuk mengkaji aktivitas antibakteri A. marina dan menentukan aktivitas antibakteri A. marina tertinggi berdasarkan jenis pelarut, bagian dan asal mangrove menggunakan metode meta-analisis. Meta-analisis ini dilakukan melalui dua prosedur, yaitu tahap pengumpulan data dan analisis data. Hasil meta-analisis menunjukkan A. marina lebih baik dalam menghambat bakteri Gram-positif dibanding bakteri Gram-negatif. Jenis pelarut, bagian, dan asal mangrove A. marina berpengaruh secara signifikan terhadap aktivitas antibakteri. Ekstrak aseton dan metanol A. marina memiliki aktivitas antibakteri yang lebih tinggi dibandingkan ekstrak etil asetat. Bagian kulit batang A. marina memiliki aktivitas antibakteri yang lebih tinggi dibandingkan bagian bunga dan daun. Avicennia marina yang berasal dari India dan Indonesia memiliki aktivitas antibakteri yang lebih tinggi dibandingkan Mesir. Research on the antibacterial activity of Avicennia marina has been carried out in the last 10 years. These various studies used various types of solvents, parts, and origins of mangroves so as to provide various conclusions regarding their antibacterial activity. Meta-analysis is research that uses similar research results and draws conclusions based on the results of the analysis. This study aims to examine the antibacterial activity of A. marina and determine the highest antibacterial activity of A. marina based on the type of solvent, part, and origin of the mangroves using a meta-analysis method. This meta-analysis was carried out through two procedures, namely the data collection and data analysis. The results of the meta-analysis showed that A. marina was better at inhibiting Gram-positive bacteria than Gram-negative bacteria. The type of solvent, part, and origin of the mangrove A. marina plant had a significant effect on the antibacterial activity. The acetone and methanol extracts of A. marina had higher antibacterial activity than ethyl acetate extracts. The stem bark of A. marina had higher antibacterial activity than the flowers and leaves. Avicennia marina originating from India and Indonesia had higher antibacterial activity than Egypt.
Keyword: Bacteria, secondary data, extract, extraction, bioactive compounds

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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