Anti-cracking mechanism of diatomite asphalt and diatomite asphalt mixture at low temperature

A kind of neat asphalt and three kinds of diatomite asphalt are tested using differential scanning calorimetry（DSC）. The anti-cracking mechanism of diatomite asphalt is analyzed by DSC and the thermal stress restrained specimen test（TSRST） of the asphalt mixtures. The results show that the low temperature performance of diatomite asphalt is better than that of neat asphalt. The glass transition temperature can reflect the low temperature performance of the diatomite asphalt better and has a good relationship with breaking temperatures. Besides, the TSRST, the bending test, the compressing test and the contraction coefficient test are used to study the low temperature performance of the diatomite asphalt mixture. The results prove that the low temperature performance of the diatomite asphalt mixture is better than that of the neat asphalt mixture. The critical bending strain energy density and the compressing strain energy density of the diatomite asphalt mixture are greater than those of the neat asphalt mixture. After adding diatomite to the asphalt mixture, the contraction coefficient is reduced. Based on the above results, the anti-cracking mechanism of the diatomite asphalt mixture is analyzed from the angle of contraction performance and breaking energy.

Lytic Characteristics and Identification of Two Alga-lysing Bacterial Strains

All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing bacteria in an algal bloom, it is difficult to isolate the alga-lysing bacteria by existing methods. In this paper, two algae-lysing bacterial strains, P01 and P03, have been isolated from a biosystem immobilized on a sponge that was highly effective in removing algae and microcystins. Their lysing modes and effects on Microcystis aeruginosa have been studied. The results show that the degradation processes of these two strains for M. aeruginosa accorded with a first-order reaction model when the chlorophylla concentration was in the range from 0 to 1000 μgL-1. The degradation rate constants were 0.1067, 0.1274 and 0.2792 for P01 and0.0683, 0.0744 and 0.028 97 for P03, when the bacterial densities were 8.6 × 105, 8.6 × 106 and 8.6 × 107cells mL-1 respectively. Moreover, the two bacterial strains had favourable lytic effects not only on M. aeruginosa , but also on Chlorella and Scene-desmus. Their lytic effect on M. aeruginosa did not require physical cell to cell contact, but proceeded by the production of an extracellular product. The bacterial strains were identified as Bacillus species by PCR amplification of the 16S rRNA gene, BLAST analysis, and comparison with sequences in the GenBank nucleotide database.

Isolation and Characterization of Fucoidans from Five Brown Algae and Evaluation of Their Antioxidant Activity

In this study, we evaluated the chemical property and antioxidant activity of fucoidans isolated from brown algae, Laminaria japonica(LJF), Lessonia nigrescens(LNF), Lessonia trabeculata(LTF), Ascophyllum mackaii(AMF), and Ecklonia maxima(EMF). LJF was less in sulfate content(14.16%) and more in galactose and mannose content(1.08 and 0.68) than the documented early. EMF contained 20%–30% of sulfate and fucose, 0.97 in molar ratio which was lower than that of sulfate to other four fucoidans(1.21–1.41). AMF(162 kDa) and EMF(150 kDa) were the first two largest in molecular weight, which were followed by LJP(126 kDa), LNF(113 kDa) and LTF(105 kDa). The fucoidans isolated these algae showed a wide range of antioxidant activity in vitro. It was found that the reducing power of the isolated fucoidans was positively correlated with their sulfate content and molecular weight. In addition, LNF and LTF at low concentrations exhibited high superoxide and hydroxyl radical scavenging activity. This demonstrated that low molecular weight fucoidans may perform a high antioxidant activity.

Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD),peroxidase (POD),catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O2ˉ).The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H.pluvialis during exposure to reactive oxygen species (ROS) such as Oˉ2.Astaxanthin reacted with ROS much faster than did the protective enzymes,and had the strongest antioxidative capacity to protect against lipid peroxidation.The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells.Astaxanthin-enriched red cells had the strongest antioxidative capacity,followed by brown cells,and astaxanthin-deficient green cells.Although there was no significant increase in expression of protective enzymes,the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin,which quenched Oˉ2 before the protective enzymes could act.In green cells,astaxanthin is very low or absent;therefore,scavenging of ROS is inevitably reliant on antioxidative enzymes.Accordingly,in green cells,these enzymes play the leading role in scavenging ROS,and the expression of these enzymes is rapidly increased to reduce excessive ROS.However,because ROS were constantly increased in this study,the enhance enzyme activity in the green cells was not able to repair the ROS damage,leading to elevated MDA content.Of the four defensive enzymes measured in astaxanthin-deficient green cells,SOD eliminates Oˉ2,POD eliminates H2O2,which is a by-product of SOD activity,and APX and CAT are then initiated to scavenge excessive ROS.

Polyhydroxyl-aluminum pillaring improved adsorption capacities of Pb^(2+) and Cd^(2+) onto diatomite

In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities （qe） of Pb^2＋ and Cd^2＋ was synthesized with the following conditions： Addition of pillaring solution containing Al3＋-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na＋-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 ℃ for 120 min; aging at a temperature of 105 ℃ for 16 h. The adsorption capacities of Pb^2＋ and Cd^2＋ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.

Variation of Bioaccumulation Ability of 2,2',4,4'-Tetrabromodiphenyl Ether by Marine Diatom Skeletonema costatum Under Different N:P Ratios

The growth, biochemical content and bioaccumulation quantity of 2,2',4,4'-tetrabromodiphenyl ether(BDE-47) in Skeletonema costatum were studied under different N:P ratios(1, 4, 16, 64 and 128). All cellular biochemical contents of S. costatum presented decreasing trend over cultivation time. At early stage of cultivation, the cellular protein, carbohydrate and lipid in S. costatum presented higher values in treatments of N:P=4 and 16. However, they were lower in these treatments at the late stage, but higher in treatments N:P=1 and 128. Similarly, BDE-47 levels per cell of S. costatum were higher in treatments of N:P=4 and 16 at early stage of cultivation, which were 3.8 and 3.7 ng(106 cells)-1, respectively. At the middle stage of cultivation, the BDE-47 level per S. costatum cell lowered; and it further reduced in the treatments of N:P=4 and 16 at the late stage with the values 0.6 and 0.5 ng(106 cells)-1, respectively. However, it rose in N:P=128, reaching up to 2.3 ng(106 cells)-1. Compared with BDE-47 per cell, BDE-47 per algal volume under different N:P ratios did not present obvious difference. The quantity BDE-47 accumulated per cell of S. costatum was positively correlated with protein, carbohydrate and lipid per cell; meanwhile, the BDE-47 per volume had a positive correlation with biochemical content per volume. The variation of bioaccumulation ability of BDE-47 in S. costatum can be explained by biochemical changes due to N:P ratios.

Study on contrast test of PPC pre-oxidation and coagulation for algae removal and deodorization

The effect of treating algae-bearing water and induced odor by use of permanganate potassium composite （PPC） pre-oxidation was investigated, and was compared with the effect of treatments by pre-chlorination, permanganate petassium pre-oxidation and simple coagulation. The results showed that simple coagulation and pre-chlorination were less effective in removing algae and its odor, whereas PPC pre-oxidation was the most effective in algae removal and deodorization. Upon oxidation with PPC, the cells of Oscillatoria agardhic were inactivated and some intra-cellular and extra-cellular components were released into the water, which may help the coagulation by their bridging effect. The efficient removal of algae by PPC pre-oxidation is believed to be the joint contribution of several mechanisms.

Improvement of Nannochloropsis oceanica growth performance through chemical mutation and characterization of fast growth physiology by transcriptome profiling

Nannochloropsis oceanica promises to be an industrial-level producer of polyunsaturated fatty acids. In this study, the fastest and slowest growing N. oceanica mutants were selected through N-methyl-N＇-nitro-N-nitrosoguanidine mutation, and two mutant strains and the wild type （WT） subjected to transcriptome profiling. It was found that the 0D680 reads at stationary growth phase of both WT and its mutants were proportional to their cell density, thus indicating their division rate and growth speed during culture. This chemical mutation was effective for improving growth performance, and the fast strain divided faster by upregulating the expression of genes functioning in the cell cycle and downregulating genes involved in synthesis of amino acids, fatty acids, and sugars as well as the construction of ribosome and photosynthetic machinery. However, the relationship among the effected genes responsible for cell cycle, metabolism of fatty and amino acids, and construction of ribosome and photosynthetic machinery remained unclear. Further genetic studies are required for clarifying the genetic/metabolic networks underpinning the growth performance ofN. oceanica. These findings demonstrated that this mutation strategy was effective for improving the growth performance of this species and explored a means ofmicroalgal genetic improvement, particularly in species possessing a monoploid nucleus and asexual reproduction.

Intraspecific genetic analysis,gamete release performance,and growth of Sargassum muticum(Fucales,Phaeophyta) from China

Sargassum muticum is one of the most abundant and conspicuous native macroalgae species on the northern coasts of China. It often forms large-scale seaweed beds in subtidal zones. This investigation was designed to understand the intraspecific genetic relationships of this alga based on samples collected from four northern coastal sites of China, and to evaluate gamete release and growth capacity in laboratory conditions. The nuclear internal transcribed spacer 2 （ITS2） sequences of 16 samples from four locations were identical. Based on cox3 gene and partial rbcLS operon sequences, intraspecific genetic variability was detected with three and two ribotypes, respectively. Temperature, not irradiance, was shown to significantly affect gamete release and fertilization. Elevated temperature and irradiance enhanced the growth of germlings and vegetative branchlets. Maximum growth rate of germlings was detected at 18-24℃and an irradiance of 60-100 μmol photons/（m^2.s）. Under ambient conditions （12-25℃ and 60-125 gmol photons/ （m2.s））, relative growth rate of young branchlets could reach 7.5%/d.

Characterized the Microalgae （Chlorella and Spirulina） and Macro Algae by Using TGA and Bomb Calorific Meter for the Biomass Energy Application

Biomass usually is noticed a composition of various types of waste materials that can be utilized as useful form of energy alternative to the conventional fossil fuels. However, this new kind of energy has not met its full potential in production of energy, especially electricity generation due to its lower performance in terms of thermal efficiency. Algae （included Microalgae ＆ Macroalgae） are widely used for multi-application developments such as fishery aquaculture, food/nutrient supplement, cosmetics, and biomass energy. Microalgae have been treated as the source of bio-fuel. In this paper, we selected the two types of freshwater microalgae ＂Chlorella Vulgaris＂ ＆ ＂Spirulina＂ and macro algae （Laminariaceae） as the main materials and we analyzed TGA （thermal gravity analysis） and calorific values （heat of combustion）. We found the calorific values are 1,000-5,000 KC/KG and TGA results show that the microalgae decrease rapidly after reached 300 ℃. The results in this paper will be used as a reference material for microalgae multi-oriental energy application and biomass composition proximate and ultimate research development in the future.

Properties of Polysaccharides in Several Seaweeds from Atlantic Canada and Their Potential Anti-Influenza Viral Activities

To explore the polysaccharides from selected seaweeds of Atlantic Canada and to evaluate their potential anti-influenza virus activities, polysaccharides were isolated from several Atlantic Canadian seaweeds, including three red algae (Polysiphonia lanosa, Furcellaria lumbricalis, and Palmaria palmata), two brown algae (Ascophyllum nodosum and Fucus vesiculosus), and one green alga (Ulva lactuca) by sequential extraction with cold water, hot water, and alkali solutions. These polysaccharides were ana-lyzed for monosaccharide composition and other general chemical properties, and they were evaluated for anti-influenza virus activities. Total sugar contents in these polysaccharides ranged from 15.4% (in U. lactuca) to 91.4% (in F. lumbricalis); sulfation level was as high as 17.6% in a polysaccharide from U. lactuca, whereas it could not be detected in an alikali-extract from P. palmaria. For polysaccharides from red seaweeds, the main sugar units were sulfated galactans (agar or carrageenan) for P. lanosa, F. lumbricalis, and xylans for P. palmata. In brown seaweeds, the polysaccharides largely contained sulfated fucans, whereas the polysaccharides in green seaweed were mainly composed of heteroglycuronans. Screening for antiviral activity against influenza A/PR/8/34 (H1N1) virus revealed that brown algal polysaccharides were particularly effective. Seaweeds from Atlantic Canada are a good source of marine polysaccharides with potential antiviral properties.

Macroalgae in a spring stream in Shanxi Province:composition and relation to physical and chemical variables

Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance were large. Twenty-two macroalgae species were found in the stream. Major divisions in terms of species numbers were Chlorophyta (59.1%), Cyanophyta (22.8%), Xanthophyta (9.1%), Rhodophyta (4.5%) and Charophyta (4.5%). The most widespread species, Cladophora rivularis (50.0%), also Oedogonium sp. (42.9%) and Spirogyra sp. (42.9%) were well represented throughout the stream, whereas another 10 species were found in only one sampling site. Total percentage cover varied from <1% to 90%. Red algae Batrachospermum acuatum and the charophytes Chara vulgaris have the highest percentage cover. Among the parameters analyzed, the stream width, specific conductance and dissolved oxygen were the ones that more closely related to the species number and percentage cover of macroalgal communities. The species number of each site was negatively correlated with dissolved oxygen content. The total percentage cover of the macroalgae was negatively correlated with the stream width and the specific conductance.

Collision-induced Rotational Energy Transfer in an Atom-Diatom System

As a further theoretical study of the collision-induced quantum interference on rotational energy transfer in an atom-diatom system, based on the first-Born approximation of time-dependent perturbation theory, taking into account the anisotropic Lennard-Jones interaction potential and the long-range interaction potential, the differential interference angles in singlet-triplet mixed states of CO A^1Π（v=9）-e3∑-（v=1） system in collision with He, Ne, Ar, and other partners were calculated theoretically. The relationships of differential interference angle versus impact parameters, including collision parameter b and velocity, are obtained.

Microalgae for Renewable Energy： Is it a Solution for Global Warming？

Microalgae could be a new sustainable energy source substituted for petroleum. They can produce high value biodiesel, bioethanol, bio-hydrogen, biogas, and that they are able to use waste water and nutrients, allowing for integration of such processes with waste treatment. Open ponds in hectares of area, could remove excess CO2 in atmosphere with photosynthesis. Large scale microalgal production in fields which are not suitable for agriculture could be a solution for CO： capturing from the atmosphere. Sea water could be used for the culture medium not to consume the fresh water. However microalgae reduce the atmospheric CO： while producing the organic material, using the biomass for either fuel production or food, feed, fertilizer, come out with CO2 release to the atmosphere, when burned by the engine, body and/or bacterial activities. So, microalgal growth can＇t reduce the CO2 however makes an important contribution to keep the atmospheric CO2 level stable. Long term solution for removing the CO2, could be possible with making durable biomaterials with microalgal biomass and capture the atmospheric CO2 by fixing into the materials and interrupt the carbon cycle for a long while.

Apparent Dissolution Kinetics of Diatomite in Alkaline Solution

The dissolution kinetics of diatomite in alkaline solution is the theoretical basis for the process optimization of alkali-diatomite reaction and its applications.In this study,the dissolution kinetics of diatomite in NaOH solution is investigated.The results indicate that the dissolution reaction fits well the unreacted shrinking core model for solid-liquid heterogeneous reactions.The apparent reaction order for NaOH is 2 and the apparent activation energy for the reaction(Ea) is 28.06 kJ·mol-1.The intra-particle diffusion through the sodium silicate layer is the rate-controlling step.When the dissolution reaction occurs at the interface of unreacted diatomite solid core,the diffusion in the trans-layer(the liquid film around the wetted particle) reduces the rate of whole dissolution process.

The possibility analysis of habitats,origin and reappearance of bloom green alga(Enteromorpha prolifera) on inshore of western Yellow Sea

Combining some information from field investigation of algae along the coastal areas in China and a few pictures materialized from the western Yellow Sea in 2008,authors analyze the necessary conditions and possible water area in China producing a large biomass,some reasons for firestorm,and the possibility of the reappearance of marine bloom green alga Enteromorpha prolifera.The change of habitats and the increase of nutritional levels related to the water area could be considered as direct reasons.It was transferred northward by the combination of the flow of rainwater,wind and alongshore marine current.The original region of large biomass produced is possibly located in the southwestern Yellow sea.It will possibly be appearing again in the coming years or in the future.A summary is also given referring to its reproduction,development and distribution worldwide.

EST analysis of Prorocentrum donghaiense with emphasis on genes involved in PCD

Prorocentrum donghaiense has caused large-scale red tides off the Chinese coast in recent years. Expressed sequence tag （EST） analysis was carried out for this dinoflagellate in order to identify the functional genes involved in its biological processes. A cDNA library was constructed for P. donghaiense at exponential growth phase, and 565 usable sequencing reads were obtained from 700 clones selected randomly. Messenger RNA corresponding reads were clustered into 36 contigs and 272 singletons （EST groups）. Twenty-two EST groups were found to tag the genes involved in diverse biological processes including programmed cell death （PCD）. Two EST groups showed significant homologies with the encoding genes of cysteine protease （caspase） and proliferating cell nuclear antigen, respectively, two key proteins involved in PCD.

Pyrolytic characteristics and kinetics of the marine green tide macroalgae, Enteromorpha prolifera

The marine macroalgae Enteromorpha prolifera was one of the main algal genera that occurred in the widespread green tides in Qingdao, China, during the summers of 2007, 2008 and 2010. It is thus a plentiful source of biomass and could be used as a biofuel. In this study, the pyrolytic characteristics and kinetics of E. prolifera were investigated using thermogravimetric analysis (TGA) method. Cornstalk and sawdust were used as comparisons. Pyrolytic characteristics were studied using TG-DTG (thermogravimetry-derivative thermogravimetry) curves. Three stages in the pyrolytic process were determined: dehydration, dramatic weight loss and slow weight loss. E. prolifera was pyrolyzed at a lower initial temperature than the two terrestrial biomass forms. The apparent activation energy values for the three types of biomass were calculated and the mechanism functions were determined using 16 different mechanism functions, frequently used in thermal kinetics analysis. Activation energy values varied with mechanism function and the range of activation energy values for E. prolifera, cornstalk, and sawdust were 25-50 kJ/mol, 60-90 kJ/mol and 120-155 kJ/mol, respectively. This indicates that E. prolifera has low thermal stability for pyrolysis and good combustion characteristics.

Prolonged Production of L-DOPA Using Immobilized Aspergillus Terreus

The objective of this study is to improve the production of L-DOPA from fungal source like Aspergillus terreus that can be further used to large-scale commercial production of this important drug from microbial sources. L-DOPA, a dopamine precursor that can pass the blood-brain barrier, is presently the drug of choice for Parkinson＇s disease. Microbial production and isolation of L-DOPA from natural sources is yet to be achieved an economical process. In this study, the mycelial pellets ofAspergillus terreus 104 were entrapped in 2% calcium alginate and were studied for their capacity for L-3, 4-dihydroxyphenylalanine production. Results showed that the immobilized pellets produced L-DOPA to the extent of 0.74 mg·G^-1 biomass while the free pellets produced 0.8 mg·G^-1 biomass. Further, storage of immobilized pellets for 96 h at 4 ℃ resulted in the reduction of the original L-DOPA producing activity of the gel beads only 40% and that of free pellets lost completely. In order to improve the production yield, further experiments were designed. It was found that L-DOPA production could be prolonged with repeated batch wise use of immobilized mycelial pellets in calcium alginate retaining 80% of their L-DOPA producing capacity for a period of 72 h while free pellets lost completely within 24 h. Results of this kind therefore is interesting and promising for commercial scale production of L-DOPA from microbial sources.

Effect of Different Nutrient Factors in the Population Growth of Heterocapsa circularisquama

A marine red tide algae denominated as Heterocapsa circularisquama was cultured under the control factors. And the ecological function of nutrient salts such as nitrogen （mg/L）, phosphorus （rag/L） as well as silicon （rag/L） in different consistency on the population growth of H. circularisquama was investigated. The results showed that overtop or too low consistency of nutrient salts both delayed the population multiplication of the red tide algae, and different nutrient factors as nitrogen, phosphorus and silicon all had significant effects on the population amplification of H.circularisquama （p〈0.01）. The optimal concentration of nitrogen, phosphorus and silicon in the culture medium for the algae propagation and growth were 10 mg/L, 1-5 mg/L and 0 mg/L respectively.