ISOLASI DAN UJI ANTIBAKTERI DARI BAKTERI YANG BERASOSIASI DENGAN SPONS Phyllospongia lamellose SERTA IDENTIFIKASI SECARA BIOKIMIA

ABSTRACT Sponges are one source of producing bioactive components from the sea. Bacteria Symbiosis with sponges are thought to have the potential to produce bioactive compounds that have been isolated from sponges. One of the potential of bioactive compounds which have been found and developed from sponges was antibacterial. The aim of this study was to determine the antibacterial activity of bacteria associated with Phyllospongia lamellose sponges against pathogenic bacteria namely Staphylococcus aureus and Esherichia coli and then proceed with identification of biochemistry in isolates which showed the greatest inhibitory activity. Three isolates of sponges symbiont bacteria were obtained through the isolation and purification stage which were then followed by testing of antibacterial activity with paper disk diffusion method. The antibacterial test results showed the diameter of the inhibitory zone against Staphylococcus aureus, were: SL1(8.67 mm), SL2 (9.33 mm) and SL3(9.00 mm) categorized as medium. Whereas the inhibiotion zone shown on Esherichia coli bacteria is also classified as medium, were: SL1(9.67 mm), SL2 (9.00 mm) and SL3 (9.33 mm). The three isolates continued to the identification stage biochemically. Each isolation was assumed as follows: Desulfotomaculum (SL1), Brochothrix (SL2) and Sulfidobacillus (SL3). Keyword         :Phyllospongia lamellose, isolation, biochemically identification ABSTRAK Spons merupakan salah satu sumber penghasil komponen bioaktif yang berasal dari laut. Bakteri yang bersimbiosis dengan spons diduga memiliki potensi dalam menghasilkan senyawa-senyawa bioaktif yang telah diisolasi dari spons. Potensi senyawa bioaktif yang telah ditemukan dan dikembangkan dari spons salah satunya ialah sebagai antibakteri. Penelitian ini bertujuan untuk mengetahui aktivitas antibakteri dari bakteri yang berasosiasi dengan spons Phyllospongia lamellose terhadap bakteri patogen yakni Staphylococcus aureus dan Escherichia coli dan kemudian dilanjutkan dengan identifikasi secara biokimia pada isolat yang menunjukkan daya hambat terbesar. Diperoleh 3 isolat bakteri simbion spons melalui tahap isolasi dan purifikasi yang kemudian dilanjutkan dengan pengujian aktivitas antibakteri melalui metode difusi kertas cakram. Hasil uji antibakteri menunjukkan diameter zona hambat terhadap bakteri Staphylococcus aureus yaitu: SL1(8.67 mm), SL2(9.33 mm) dan SL3 (9.00 mm) termasuk dalam kategori sedang. Sedangkan zona hambat yang ditunjukkan terhadap bakteri Escherichia coli juga tergolong kategori sedang yaitu: SL1(9.67 mm), SL2(9.00 mm) dan SL3 (9.33 mm). Ketiga isolat dilanjutkan ke tahap identifikasi secara biokimia. Masing-masing isolat diduga sebagai berikut: Desulfotomaculum (SL1), Brochothrix (SL2) dan Sulfidobacillus (SL3). Kata kunci          :Phyllospongia lamellose, isolasi, identifikasi biokimia

The interaction between colloids in polar mixtures above Tc

We calculate the interaction potential between two colloids immersed in an aqueous mixture containing salt near or above the critical temperature. We find an attractive interaction far from the coexistence curve due to the combination of preferential solvent adsorption at the colloids' surface and preferential ion solvation. We show that the ion-specific interaction strongly depends on the amount of salt added as well as on the mixture composition. Our results are in accord with recent experiments. For a highly antagonistic salt of hydrophilic anions and hydrophobic cations, a repulsive interaction at an intermediate inter-colloid distance is predicted even though both the electrostatic and adsorption forces alone are attractive.Comment: 9 pages, 6 figure

Extensión universitaria: memorias correspondientes á los cursos de 1898 á 1909

Precede al tit.: Universidad de Ovied

No-splitting property and boundaries of random groups

We prove that random groups in the Gromov density model, at any density, satisfy property (FA), i.e. they do not act non-trivially on trees. This implies that their Gromov boundaries, defined at density less than 1/2, are Menger curves.Comment: 20 page

Shot noise suppression at room temperature in atomic-scale Au junctions

Shot noise encodes additional information not directly inferable from simple electronic transport measurements. Previous measurements in atomic-scale metal junctions at cryogenic temperatures have shown suppression of the shot noise at particular conductance values. This suppression demonstrates that transport in these structures proceeds via discrete quantum channels. Using a high frequency technique, we simultaneously acquire noise data and conductance histograms in Au junctions at room temperature and ambient conditions. We observe noise suppression at up to three conductance quanta, with possible indications of current-induced local heating and $1/f$ noise in the contact region at high biases. These measurements demonstrate the quantum character of transport at room temperature at the atomic scale. This technique provides an additional tool for studying dissipation and correlations in nanodevices.Comment: 15 pages, 4 figures + supporting information (6 pages, 6 figures

Radiasi medan elektromagnetik pada jangkauan frekuensi sangat rendah (extremely low frequency) di lingkungan Kmapus Universitas PGRI Yogyakarta (turnitin)

turniti

Radiasi Medan Elektromagnetik pada Jangkauan Frekuensi Sangat Rendah (Extremely Low Frequency) di Lingkungan Kampus Universitas PGRI Yogyakarta

Kekhawatiran masyarakat mengenai dampak negatif yang ditimbulkan dari paparan radiasi elektromagnetik ini masih terus diteliti hingga saat ini. Oleh karena itu, sangat perlu dilakukan suatu studi penelitian untuk mengukur dan memetakan tingkat radiasi elektromagnetik dengan tujuan menganalisis potensi risiko yang terjadi. Paparan radiasi elektromagnetik diukur menggunakan electromagnetic field tester, kemudian hasilnya dibandingkan dengan pedoman keselamatan yang dikeluarkan oleh ICNIRP dan WHO. Hasil yang diperoleh bahwa tingkat paparan radiasi yang diukur dalam satuan mikrotesla di 29 titik lokasi di Universitas PGRI Yogyakarta jauh di bawah pedoman ICNIRP untuk lingkungan pendidikan dan kerja. Nilai medan magnet terukur tertinggi adalah 132,46 μT, sedangkan nilai medan magnet terukur terendah adalah 1,436 μT. Medan magnet diatas 0,3 hingga 0,4 μT dapat meningkatkan risiko leukimia dalam jangka panjang. Penelitian ini telah menghasilkan informasi yang bermanfaat sebagai dasar pengambilan kebijakan kesehatan di lingkungan kampus Universitas PGRI Yogyakart

Counting statistics in multiple path geometries and the fluctuations of the integrated current in a quantum stirring device

The amount $Q$ of particles that are transported via a path of motion is characterized by its expectation value $$ and by its variance $Var(Q)$. We analyze what happens if a particle has two optional paths available to get from one site to another site, and in particular what is $Var(Q)$ for the current which is induced in a quantum stirring device. It turns out that coherent splitting and the stirring effect are intimately related and cannot be understood within the framework of the prevailing probabilistic theory.Comment: 11 pages, 2 figures, published version, Latex Eq# correcte

Observing the universal screening of a Kondo impurity

The Kondo effect, deriving from a local magnetic impurity mediating electron-electron interactions, constitutes a flourishing basis for understanding a large variety of intricate many-body problems. Its experimental implementation in tunable circuits has made possible important advances through well-controlled investigations. However, these have mostly concerned transport properties, whereas thermodynamic observations - notably the fundamental measurement of the spin of the Kondo impurity - remain elusive in test-bed circuits. Here, with a novel combination of a "charge" Kondo circuit with a charge sensor, we directly observe the state of the impurity and its progressive screening. We establish the universal renormalization flow from a single free spin to a screened singlet, the associated reduction in the magnetization, and the relationship between scaling Kondo temperature and microscopic parameters. In our device, a Kondo pseudospin is realized by two degenerate charge states of a metallic island, which we measure with a non-invasive, capacitively coupled charge sensor. Such pseudospin probe of an engineered Kondo system opens the way to the thermodynamic investigation of many exotic quantum states, including the clear observation of Majorana zero modes through their fractional entropy