Potentiality of Using Spreading Sargassum Species From Indonesia as an Interesting Source of Antibacterial and Radical Scavenging Compounds: a Preliminary Study

As an archipelagic country with 95,181 km long coastline, Indonesia has great potential as the producer of seaweeds. The diverse phyla of marine macroalgae (red, brown and green seaweeds) are known to produce molecules which are attractive for diverse industries. Applications of algal products range from simple biomass production for food, feed and fuels to valuable products such as sugar polymers, cosmetics, pharmaceuticals, pigments, and food supplements. Seaweeds also have the potential to be used as a source of new bioactive for human, animal or plant health, as well as a source of new synthons and biocatalysts in sustainable chemistry (Bourgougnon and Stiger-Pouvreau, 2011). In this paper, among species of economic value we focus on brown seaweeds belonging to family Sargassaceae and genus Sargassum spreading along Indonesian coasts. Members of this genus are especially abundant in tropical and subtropical regions (Zemke-White and Ohno, 1999). The purpose of this study is to analyze the antibacterial and antioxidant activity of three species of Sargassum, i.e. S. echinocarpum, S. duplicatum and S. polycystum. Both polar and non-polar extracts have been prepared from those three species. In vitro antibacterial activities of extracts were evaluated against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. Results indicated all the three species tested showed an antibacterial activity. The most effective antibacterial activity against S. aerous was from S. echinocarpum with ethil asetat, inhibition zone 1.13 ± 0.25 mm; S. duplicatum with N-Hexane was most effective against E. coli, 1.20 ± 0.28 mm

Research to understand and predict geopressured reservoir characteristics with confidence

The Department of Energy's Geopressured Geothermal Program has sponsored a series of geoscience studies to resolve key uncertainties in the performance of geopressured reservoirs. The priority areas for research include improving the ability to predict reservoir size and flow capabilities, understanding the role of oil and gas in reservoir depletion and evaluating mechanisms for reservoir pressure maintenance. Long-term production from the Gladys McCall well has provided the basis for most of the current research efforts. The well was shut-in on October 29, 1987, for pressure recovery after producing over 27 million barrels of brine with associated gas. Geologic investigations are evaluating various mechanisms for pressure maintenance in this reservoir, including recharge from adjacent reservoirs or along growth faults, shale dewatering, and laterally overlapping and connected sandstone layers. Compaction studies using shale and sandstone core samples have provided data on the relationship between rock compression and reservoir pressure decline and the correlation to changes in porosity and permeability. The studies support the use of a porosity-coupled reservoir simulation model which has provided an excellent match to the well's production history. 10 refs., 3 figs

Topological entropy of a stiff ring polymer and its connection to DNA knots

We discuss the entropy of a circular polymer under a topological constraint. We call it the {\it topological entropy} of the polymer, in short. A ring polymer does not change its topology (knot type) under any thermal fluctuations. Through numerical simulations using some knot invariants, we show that the topological entropy of a stiff ring polymer with a fixed knot is described by a scaling formula as a function of the thickness and length of the circular chain. The result is consistent with the viewpoint that for stiff polymers such as DNAs, the length and diameter of the chains should play a central role in their statistical and dynamical properties. Furthermore, we show that the new formula extends a known theoretical formula for DNA knots.Comment: 14pages,11figure

Simple and Rapid Voltammetric Method Using a Gold Microwire Electrode to Measure Inorganic Arsenic in Holopelagic <i>Sargassum</i> (Fucales, Phaeophyceae)

The valorization of massive strandings of holopelagic Sargassum spp. is strongly limited by high levels of inorganic arsenic (Asi) that are potentially above the limit of current regulations. Monitoring Asi in algal biomass is currently achieved using standard chromatographic separation followed by spectroscopic detection. Here, we propose an alternative simpler procedure based on the extraction of Asi from the freeze-dried algal powder in deionized water and the electroanalytical detection of the diluted extract at a gold-microwire electrode. The protocol was optimized both in terms of extraction (powder/water ratio, extraction time, temperature) and electrolyte used for the voltammetric detection. Two electrolytes were tested: one composed of citric acid, sulfamic acid and KCl (pH 2.0) and another composed of an acetate buffer (pH 4.7) and NaCl. We demonstrate here that Asi determination is possible with the first electrolyte but it is necessary to deal with a relative unstable signal. Measurement of Asi was best achieved with the second electrolyte (acetate buffer and NaCl) with the following optimized electrochemical conditions: deposition potential of −1.2 V, deposition time of 30 seconds and linear scan voltammetry. Voltammetric results were then compared to a reference method (HPLC-ICP-MS) using different morphotypes of holopelagic Sargassum spp. (S. natans VIII, S. natans I and S. fluitans III), using commercial extracts of brown seaweeds and using a Hijiki certified reference material. Very good agreement was obtained between our novel method and HPLC-ICP-MS. Both methods show that inorganic arsenic is almost entirely present as As(V) in Sargassum spp. extracts

Multi-layered Ruthenium-modified Bond Coats for Thermal Barrier Coatings

Diffusional approaches for fabrication of multi-layered Ru-modified bond coats for thermal barrier coatings have been developed via low activity chemical vapor deposition and high activity pack aluminization. Both processes yield bond coats comprising two distinct B2 layers, based on NiAl and RuAl, however, the position of these layers relative to the bond coat surface is reversed when switching processes. The structural evolution of each coating at various stages of the fabrication process has been and subsequent cyclic oxidation is presented, and the relevant interdiffusion and phase equilibria issues in are discussed. Evaluation of the oxidation behavior of these Ru-modified bond coat structures reveals that each B2 interlayer arrangement leads to the formation of α-Al 2 O 3 TGO at 1100°C, but the durability of the TGO is somewhat different and in need of further improvement in both cases

Geothermal direct use engineering and design guidebook

The Geothermal Direct Use Engineering and Design Guidebook is designed to be a comprehensive, thoroughly practical reference guide for engineers and designers of direct heat projects. These projects could include the conversion of geothermal energy into space heating cooling of buildings, district heating, greenhouse heating, aquaculture and industrial processing. The Guidebook is directed at understanding the nature of geothermal resources and the exploration of these resources, fluid sampling techniques, drilling, and completion of geothermal wells through well testing, and reservoir evaluation. It presents information useful to engineers on the specification of equipment including well pumps, piping, heat exchangers, space heating equipment, heat pumps and absorption refrigeration. A compilation of current information about greenhouse, aquaculture and industrial applications is included together with a discussion of engineering cost analysis, regulation requirements, and environmental considerations. The purpose of the Guidebook is to provide an integrated view for the development of direct use projects for which there is a very potential in the United States

Bone Mass and the CAG and GGN Androgen Receptor Polymorphisms in Young Men

BACKGROUND: To determine whether androgen receptor (AR) CAG (polyglutamine) and GGN (polyglycine) polymorphisms influence bone mineral density (BMD), osteocalcin and free serum testosterone concentration in young men. METHODOLOGY/PRINCIPAL FINDINGS: Whole body, lumbar spine and femoral bone mineral content (BMC) and BMD, Dual X-ray Absorptiometry (DXA), AR repeat polymorphisms (PCR), osteocalcin and free testosterone (ELISA) were determined in 282 healthy men (28.6+/-7.6 years). Individuals were grouped as CAG short (CAG(S)) if harboring repeat lengths of < or = 21 or CAG long (CAG(L)) if CAG > 21, and GGN was considered short (GGN(S)) or long (GGN(L)) if GGN < or = 23 or > 23. There was an inverse association between logarithm of CAG and GGN length and Ward's Triangle BMC (r = -0.15 and -0.15, P<0.05, age and height adjusted). No associations between CAG or GGN repeat length and regional BMC or BMD were observed after adjusting for age. Whole body and regional BMC and BMD values were similar in men harboring CAG(S), CAG(L), GGN(S) or GGN(L) AR repeat polymorphisms. Men harboring the combination CAG(L)+GGN(L) had 6.3 and 4.4% higher lumbar spine BMC and BMD than men with the haplotype CAG(S)+GGN(S) (both P<0.05). Femoral neck BMD was 4.8% higher in the CAG(S)+GGN(S) compared with the CAG(L)+GGN(S) men (P<0.05). CAG(S), CAG(L), GGN(S), GGN(L) men had similar osteocalcin concentration as well as the four CAG-GGN haplotypes studied. CONCLUSION: AR polymorphisms have an influence on BMC and BMD in healthy adult humans, which cannot be explained through effects in osteoblastic activity