Penapisan Senyawa Fitokimia Dan Pengujian Antioksidan Ekstrak Daun Pohon Merapat

Hutan kerangas merupakan kumpulan vegetasi pohon di hutan hujan tropis, dicirikan antara lain oleh kandungan hara dan keanekaragaman hayati yang rendah, sehingga penggunaan pohonnya menjadi terbatas. Hutan kerangas tersebar luas di Kalimantan (misalnya Kalimantan Selatan). Salah satu jenis pohon yang dapat tumbuh dan berkembang pada kondisi ekstrim adalah merapat (Combretocarpus rotundatus). Daunnya mengandung senyawa kimia tertentu yang mengindikasikan berkemampuan fisiologis menghasilkan bioaktivitas seperti antioksidan. Sebagai konsekuesinya, hal ini diharapkan dapat meningkatkan nilai tambah dari pemanfaatan pohon kerangas. Terkait hal tersebut, pencermatan terhadap kandungan senyawa fitokimia dan pengujian kemampuan antioksidan dilakukan terhadap sampel kering daun merapat yang berasal dari hutan kerangas di Kalimantan Selatan. Awalnya, daun kering diekstrak dengan larutan metanol menghasilkan ekstrak methanol (sampel 1), fraksinasi lanjutan dilakukan dengan kromatografi kolom menggunakan eluent kloroform. Fraksi kloroform yang didapatkan (sampel 2) selanjutnya difraksinasi kembali menggunakan campuran larutan etil asetat-kloroform (dengan proporsi sama), yang menghasilkan sampel 3. Pencermatan fitokimia mengungkapkan bahwa ekstrak metanol mengandung senyawa fitokimia tertentu seperti flavonoid, turunan phenol, hidrokuinon, tanin dan triterpenoid, yang berperan sebagai antioksidan. Ekstrak metanol (sampel 1) menunjukkan aktivitas antioksidan tertinggi dengan memberikan reaksi reduksi terhadap pelepasan radikal bebas oleh Difenil Pikril Hidrazil Hidrat (DPPH) (2,2-diphenyl-1-picrylhydrazyl), walaupun penggunaan dari fraksi kloroform (sampel 2) dan fraksi lanjutan etil asetat-kloroform (sampel 3) sangat rendah. Penghambatan radikal bebas dari DPPH pada tingkat 50% (IC 50) oleh ekstrak metanol terjadi pada konsentrasi 21,823 ppm. Sementara itu, vitamin C dan BHT sebagai kontrol aktivitas antioksidan terbentuk lebih efisien pada konsentrasi di bawah 21,823 ppm (berturut-turut pada konsentrasi 6,738 ppm dan 6,279 ppm). Bagaimanapun, nilai IC 50 tersebut memberikan penjelasan kuat bahwa potensi bioaktivitas ekstrak metanol daun merapat dapat digunakan sebagai antioksidan

Analysis of Sertoli Cell-Secreted Proteins by Two-Dimensional Gel Electrophoresis

The [35S]methionine-labeled proteins secreted from cultured Sertoli cells were analyzed by two-dimensional gel electrophoresis and fluorography. Major polypeptides which were resolved by this procedure were designated by number and further analyzed. Many of these major polypeptides appeared as a series of spots which corresponded to charge isomers. Two of these polypeptides (5 and 6) were shown to be acidic, glycosylated and to comprise the subunits of a dimeric protein of molecular weight 70,000. Some of the polypeptides (4a and 5a) were shown to be secreted from testicular peritubular cells which contaminated the Sertoli cell cultures. However, many of the polypeptides (1,2,3,4,5,5b and 6) were specifically secreted from the Sertoli cells. The fluorogram of the secreted polypeptides obtained from cultured Sertoli cells from 20- or 60-day-old rats were similar to each other but differed from the pattern of polypeptides which were secreted from cultures of Sertoli cells from 10-day-old rats. Polypeptide 3 was identified by immunoprecipitation as testicular transferrin and the synthesis of polypeptide 3 was stimulated when the Sertoli cells were cultured in the presence of follicle-stimulating hormone (FSH), insulin, testosterone and retinol

Dislocation generation and propagation during flash lamp annealing

Dislocation generation and propagation during flash lamp annealing for 20 ms was investigated using wafers with sawed, ground, and etched surfaces. Due to the thermal stress resulting from the temperature profiles generated by the flash pre-existing dislocations propagate into the wafer from both surfaces during flash lamp annealing. A dislocation free zone was observed around 700 μm depth below the surface of a 900 μm thick sawed wafer. The dislocation propagation can be well described by a three-dimensional mechanical model. It was further demonstrated that in wafers being initially free of dislocations no dislocations are generated during flash lamp annealing

On the Impact of Strained PECVD Nitride Layers on Oxide Precipitate Nucleation in Silicon

PECVD nitride layers with different layer stress ranging from about 315 MPa to −1735 MPa were deposited on silicon wafers with similar concentration of interstitial oxygen. After a thermal treatment consisting of nucleation at 650°C for 4 h or 8 h followed annealing 780°C 3 h + 1000°C 16 h in nitrogen, the profiles of the oxide precipitate density were investigated. The binding states of hydrogen in the layers was investigated by FTIR. There is a clear effect of the layer stress on oxide precipitate nucleation. The higher the compressive layer stress is the higher is a BMD peak below the front surface. If the nitride layer is removed after the nucleation anneal the BMD peak below the front surface becomes lower. It is possible to model the BMD peak below the surface by vacancy in-diffusion from the silicon/nitride interface. With increasing duration of the nucleation anneal the vacancy injection from the silicon/nitride interface decreases and with increasing compressive layer stress it increases. © The Author(s) 2019

HYDROGEN BONDING IN betabeta-NITRO ALCOHOLS. III. PYRIDINE COMPLEXES

BETA -Nitro alcohols form stable 1:1 complexes with pyridine, examples of which were prepared. In solvents such as dichloromethane and carbon tetrachloride the complexes partially dissociate into their components. The dissociation constants for the equilibria were determined by infrared methods and may be used as a measure of the strength of the complex hydrogen bond. The dissociation constants decrease with increasing number of BETA -nitro groups. Some reactions of the pyridine complexes are described. (auth

Finite size effects in nonequilibrium wetting

Models with a nonequilibrium wetting transition display a transition also in finite systems. This is different from nonequilibrium phase transitions into an absorbing state, where the stationary state is the absorbing one for any value of the control parameter in a finite system. In this paper, we study what kind of transition takes place in finite systems of nonequilibrium wetting models. By solving exactly a microscopic model with three and four sites and performing numerical simulations we show that the phase transition taking place in a finite system is characterized by the average interface height performing a random walk at criticality and does not discriminate between the bounded-KPZ classes and the bounded-EW class. We also study the finite size scaling of the bKPZ universality classes, showing that it presents peculiar features in comparison with other universality classes of nonequilibrium phase transitions.Comment: 14 pages, 6figures, major change

Contact processes with long-range interactions

A class of non-local contact processes is introduced and studied using mean-field approximation and numerical simulations. In these processes particles are created at a rate which decays algebraically with the distance from the nearest particle. It is found that the transition into the absorbing state is continuous and is characterized by continuously varying critical exponents. This model differs from the previously studied non-local directed percolation model, where particles are created by unrestricted Levy flights. It is motivated by recent studies of non-equilibrium wetting indicating that this type of non-local processes play a role in the unbinding transition. Other non-local processes which have been suggested to exist within the context of wetting are considered as well.Comment: Accepted with minor revisions by Journal of Statistical Mechanics: Theory and experiment

TcruziDB: an integrated, post-genomics community resource for Trypanosoma cruzi

TcruziDB () is an integrated post-genomics database for the parasitic organism, Trypanosoma cruzi, the causative agent of Chagas' disease. TcruziDB was established in 2003 as a flat-file database with tools for mining the unannotated sequence reads and preliminary contig assemblies emerging from the Tri-Tryp genome consortium (TIGR/SBRI/Karolinska). Today, TcruziDB houses the recently published assembled genomic contigs and annotation provided by the genome consortium in a relational database supported by the Genomics Unified Schema (GUS) architecture. The combination of an annotated genome and a relational architecture has facilitated the integration of genomic data with expression data (proteomic and EST) and permitted the construction of automated analysis pipelines. TcruziDB has accepted, and will continue to accept the deposition of genomic and functional genomic datasets contributed by the research community

Regional-scale brine migration along vertical pathways due to CO2 injection - Part 1: The participatory modeling approach

Saltwater intrusion into potential drinking water aquifers due to the injection of CO₂ into deep saline aquifers is one of the potential hazards associated with the geological storage of CO₂. Thus, in a site selection process, models for predicting the fate of the displaced brine are required, for example, for a risk assessment or the optimization of pressure management concepts. From the very beginning, this research on brine migration aimed at involving expert and stakeholder knowledge and assessment in simulating the impacts of injecting CO₂ into deep saline aquifers by means of a participatory modeling process. The involvement exercise made use of two approaches. First, guideline-based interviews were carried out, aiming at eliciting expert and stakeholder knowledge and assessments of geological structures and mechanisms affecting CO₂-induced brine migration. Second, a stakeholder workshop including the World Café format yielded evaluations and judgments of the numerical modeling approach, scenario selection, and preliminary simulation results. The participatory modeling approach gained several results covering brine migration in general, the geological model sketch, scenario development, and the review of the preliminary simulation results. These results were included in revised versions of both the geological model and the numerical model, helping to improve the analysis of regional-scale brine migration along vertical pathways due to CO₂ injection