Uji Antimikroba Fraksi Ekstrak Metanol, Etil Asetat dan n-Heksana Daun Tabar-Tabar (Costus speciosus) dan Toksisitasnya Terhadap Larva Udang

A Study on antimicrobial examination of fractions of methanol, ethyl-acetate, and n-hexane extract of tabar-tabar (Costus speciosus) leaf to bacteria (Bacillus sp., Staphylococcus aureus, Escherichia coli, and Serratia marcescens) and yeast (Candida albicans), and their toxicity to brine-shrimp (Artemia salina) larvae has been done. Examination of antimicrobial activities to the microbes were done by agar diffusion method, while test for toxicity was done by exposing 2 days-old larvae to certain concentration of the extract. Preliminary tests on phytochemical compounds in leaf were done by Mayer’s, FeCl3, Mg-HCl, foam, and 10% NaOH in methanol tests. The results showed that methanol leaf extract of tabar-tabar in general inhibited more in the growth of gram-positive Bacillus sp. and S. aureus rather than to other tested microbes. Compared to methanol and ethyl-acetate fraction, n-hexane fraction of the leaf inhibited more Bacillus sp. and E. coli. Interestingly, C. albicans was highly inhibited by n-hexane fractions. LC50 of methanol extract, ethyl-acetate, and n-hexane fraction, were 45.53, 478.37, and 824.20 ppm, respectively. Preliminary test on phytochemical compounds showed saponin was only detected in fractions of methanol and ethyl acetate extracts, steroid was detected in fraction of methanol, while triterpenoid was detected in fraction of n-hexane extract. Phenolic was detected in all extract fractions, while flavonoid, kumarin, and alkaloid on the other hand were not detected

Electrophoretic Properties of Highly Charged Colloids: A Hybrid MD/LB Simulation Study

Using computer simulations, the electrophoretic motion of a positively charged colloid (macroion) in an electrolyte solution is studied in the framework of the primitive model. Hydrodynamic interactions are fully taken into account by applying a hybrid simulation scheme, where the charged ions (i.e. macroion and electrolyte), propagated via molecular dynamics (MD), are coupled to a Lattice Boltzmann (LB) fluid. In a recent experiment it was shown that, for multivalent salt ions, the mobility $\mu$ initially increases with charge density $\sigma$, reaches a maximum and then decreases with further increase of $\sigma$. The aim of the present work is to elucidate the behaviour of $\mu$ at high values of $\sigma$. Even for the case of monovalent microions, we find a decrease of $\mu$ with $\sigma$. A dynamic Stern layer is defined that includes all the counterions that move with the macroion while subject to an external electrical field. The number of counterions in the Stern layer, $q_0$, is a crucial parameter for the behavior of $\mu$ at high values of $\sigma$. In this case, the mobility $\mu$ depends primarily on the ratio $q_0/Q$ (with $Q$ the valency of the macroion). The previous contention that the increase in the distortion of the electric double layer (EDL) with increasing $\sigma$ leads to the lowering of $\mu$ does not hold for high $\sigma$. In fact, we show that the deformation of the EDL decreases with increase of $\sigma$. The role of hydrodynamic interactions is inferred from direct comparisons to Langevin simulations where the coupling to the LB fluid is switched off. Moreover, systems with divalent counterions are considered. In this case, at high values of $\sigma$ the phenomenon of charge inversion is found.Comment: accepted in J. Chem Phys., 10 pages, 9 figure

Empirical Model of Unconsolidated Tephra Erosion: Verification and Application on Micro Catchment

Erosion is an important process that shapes the earth's surface. Given the complexity of the process, efforts to understand it are essential. Over the last 50 years, numerous models of soil particle erosion by surface runoff emerged, some of which share similar forms and parameters. The differences lie in the coefficient values of the parameters, attributed to the characteristics of the soil material such as texture, structure, and organic matter content. However, these erosion models tend to underpredict in the case of new volcanic deposit erosion. The erosion model for unconsolidated tephra, proposed by Yunita, was developed through laboratory experiments using volcanic material from Merapi Volcano, Indonesia. Nevertheless, the model has not been implemented for other cases. Therefore, this study aims to verify the erosion model for volcanic material in other cases, explore the possibility of broader implementation, identify the factors that influence its accuracy, and determine the model’s limitations. To verify the model’s potential for broader application, we applied it to micro-scale catchments in St. Hellens (USA), Sakurajima (Japan), and a laboratory scale plot in Merapi (Indonesia). The verification yielded satisfactory results for all three cases, especially for new tephra deposits. In the case of St. Helens, the extrapolation of model coefficients was proven to still be applicable even for thicker tephra layers. However, the erosion prediction was overestimated for tephra layer deposits older than 1 year, as the erosion rate decreases over time due to the compaction and stabilization of the tephra layer. In the Sakurajima, the model was also suitable for predicting long-term erosion amounts (daily and monthly). Meanwhile, in Merapi, the model provided accurate predictions for slopes of 20º and 25º but was less accurate for 30º slopes, where the measured erosion was due to both erosion and slope failure. These verification results demonstrate the potential of applying the empirical erosion model to micro catchments with relatively homogenous slopes and tephra properties. The sensitivity test revealed that slope, runoff, rainfall intensity, and volcanic ash thickness are strongly influence the erosion rate. This study also simplified the volcanic ash erosion model as a function of slope (S0), runoff (q), and rainfall (i) by assuming the value of (1-τc/τ0) is equal to 1. Further study using GIS tools is required for its application on several catchments with heterogeneous characteristics. Doi: 10.28991/CEJ-2024-010-07-02 Full Text: PD

Karakteristik Morfologi dan Pola Pita Izosim Varietas Mangga (Mangifera SP.) di Kabupaten Banyumas

Mangga (Mangifera indica) merupakan salah satu tanaman hortikultura yang memiliki nilai ekonomi tinggi. Untuk membedakan antara varietas mangga, penanda genetik yang digunakan karena mereka tidak dipengaruhi oleh faktor lingkungan. Salah satu penanda genetik yang sering digunakan adalah Isozim. Tujuan penelitian ini adalah untuk mengetahui pola bandeng dan variasi genetik beberapa varietas mangga dari Kabupaten Banyumas berdasarkan peroksidase isozim (PER), aspartate aminotransferase (AAT), esterase (EST), asam fosfatase (ACP). Penelitian ini dilakukan di Pabrik Laboratorium Biologi, Biologi Pusat Penelitian Ilmu, IPB, Bogor dari Juni sampai September 2012. Sampling daun dari tujuh varietas mangga dilakukan dengan purposive random sampling. Setelah eletrophoresis dan scoring, data kemudian dianalisis dengan Unweighted Pair-group Method with Arithmetic (UPGMA) under Numerical Taxonomy and Multivariate Sistem (NTSYS) version 2.20i. Hasil penelitian menunjukkan bahwa EST memiliki empat pola pita yang bermigrasi anodally. AAT memiliki lima pola banding dan ACP memiliki lima pola pita yang bermigrasi anodally. PER memiliki lima pola pita yang bermigrasi anodally dan katodally, MG4 (lokal dari indramayu mangga) tidak muncul. PER, AAT, ACP dan ACP menunjukkan pola yang berbeda dari dendogram. Kombinasi dari empat isozim menunjukkan bahwa variasi genetik antara MG4 (mangga lokal indramayu) dan MG5 (mangga lokal dari gedonggincu) adalah 79%, MG1 (lokal dari golek mangga) dan Mg3 (mangga lokal arummanis) adalah 75 %

Tingkat Kerawanan Kebakaran Gambut Di Kabupaten Musi Banyuasin, Sumatera Selatan (Peat Fire Susceptibility in Musi Banyuasin District, South Sumatra)

Forest and land fire in 2015 was a catastrophe in Indonesia, as it did not only cause damage on forest ecosystem and environments, but also impacted human health and economic loss. This research aimed to identify hotspots distribution in 2014-2015 as an indicator of forest and land fire, and to analyze fire susceptibility in Musi Banyuasin district, South Sumatra. Data used for fire prone analysis consisted of land cover map, forest status, hotspots data derived from NOAA18, soil types, topography and moratorium map. Results showed that based on land function, hotspots were mostly found in production forest with hotspots density of 0.049 hotspots km-2. Based on land cover type, hotspots were mostly found in the open land (88 hotspots). Based on soil types, hotspots were mostly occurred on peat soils (180 hotspots and hotspot density 0.048 hotspot km-2). Soil type was mostly associated with hotspot occurrence. Sub-district of Bayung Lencir has the highest fire susceptibility among others. Low precipitation and El-Ninö phenomenon in 2015 were not the only drivers of peat fire. However two main current problems in the Forest Management Unit of Lalan Mangsang Mendis (e.g. illegal logging and open access) were driver factors of peat fire in the district

Studi Interior Rumah Tradisional Yogyakarta Dalem Mangkubumen, Dalem Notoprajan, Dalem Ngadiwinatan, Dalem Yudhonegaran, Dalem Kasatrian

Sejak awal kehidupan manusia, orang selalu mencoba untuk membuat lingkungan sekelililngnya menjadi lebih menyenangkan, lebih efisien dan lebih menguntungkan untuk mereka. Desain interior tidak lepas dari desain bangunan, walaupun penekanannya masing-masing berbeda. Dalam interior yang menjadi pokok adalah aktivitas dan tingkah laku manusia serta kebutuhannya akan ruang, sedangkan arsitektur menyangkut masalah yang lebih luas yaitu bentuk bangunan dan konstruksinya serta lingkungan fisiknya. Penelitian interior rumah tradisional belum banyak dilakukan kecuali sekedar merupakan bagian dari penelitian arsitektur. Tujuan dari penelitian ini adalah (1) Memperoleh data tentang interior rumah tradisional Jawa, khususnya Yogyakarta; (2)Mencoba mengisi kekosongan konsepsi, pendekatan dan metoda untuk perancangan interior di DIY; (3) Mencoba mengembangkan "jembatan" antara ilmu yang sangat berkaitan dengan desain interior, yaitu ilmu teknik, dan ilmu-ilmu lain seperti sosiologi, antropologi dan psikologi

PERANCANGAN KAMPANYE SOSIAL LINDUNGI ANAK DARI CYBERBULLYING. Mellya Febriana Nur Hasanah 126010030

Perkembangan teknologi informasi, internet dan media sosial memberikan dampak perubahan pada perilaku manusia dalam bersosial dan berkomunikasi. Banyak anak-anak atau remaja yang menggunakan media sosial untuk saling berkomunikasi. Perkembangan tersebut dapat menimbulkan dampak buruk, komunikasi tanpa pengawasan dalam lingkup sosial akan menyebabkan berbagai macam penyimpangan, sebagai contoh yang sering kita dengar dengan istilah cyberbullying. Orang tua tidak sadar bahkan tidak paham dan mengerti cyberbullying itu apa, maka banyak dari orang tua sekarang sebagian anaknya pernah mengalami cyberbullying baik itu sebagai korban ataupun pelaku. Dalam penulisan kali ini akan membahas bagaimana cara mengatasi atau menangani cyberbullying pada anak dengan kampanye sosial. Kata Kunci : Media sosial, Cyberbullying, Orang tua, Ana