The role of magnetite (Fe3O4) particles for enhancing the performance and granulation of anammox.

In this study, two lab-scale sequencing batch reactors each with an effective volume of 2.3 L were operated as C-AMX (no carrier addition) and M-AMX (magnetite carrier added) for 147 days with synthetic wastewater at an NLR range of 0.19-0.47 kgN/m3/d. The long-term effect of magnetite on the granulation and performance of anammox bacteria in terms of nitrogen removal and other essential parameters were confirmed. In phase I (1-24 days), M-AMX took approximately 12 days to obtain a nitrogen removal rate (NRR) above 80 % of the initial input nitrogen. Although free nitrous acid inhibited the reactor at a high concentration at the onset of phase III, the NRR of M-AMX recovered about 3.7 times faster than that of C-AMX. In addition, it was confirmed that the M-AMX granules had a dense and compact structure compared to C-AMX, and the presence of the carrier promoted the development of these resilient granules. While the measured microbial stress gradually increased in C-AMX reactor, a vice versa was observed in the M-AMX reactor as granulation proceeded. Compared to other alternative iron-based carrier particles, the stable crystal structure of magnetite as a carrier created a mechanism where filamentous bacteria groups were repelled from the granulation hence the microbial stress in the M-AMX in the final phase was 61.54 % lower than that in the C-AMX. The iron rich environment created by the magnetite addition led to Ignavibacteria, (a Feammox bacteria) increasing significantly in the M-AMX bioreactor.

Dynamic calibration of process-wide partial-nitritation modeling with airlift granular for nitrogen removal in a full-scale wastewater treatment plant.

A main challenge in rapid nitrogen removal from rejected water in wastewater treatment plants (WWTPs) is growth of biomass by nitrite-oxidizing bacteria (NOB) and ammonia-oxidizing bacteria (AOB). In this study, partial nitritation (PN) coupled with air-lift granular unit (AGU) technology was applied to enhance nitrogen-removal efficiency in WWTPs. For successful PN process at high-nitrogen-influent conditions, a pH of 7.5-8 for high free-ammonia concentrations and AOB for growth of total bacterial populations are required. The PN process in a sequential batch reactor (SBR) with AGU was modeled as an activated sludge model (ASM), and dynamic calibration using full-scale plant data was performed to enhance aeration in the reactor and improve the nitrite-to-ammonia ratio in the PN effluent. In steady-state and dynamic calibrations, the measured and modeled values of the output were in close agreement. Sensitivity analysis revealed that the kinetic and stoichiometric parameters are associated with growth and decay of heterotrophs, AOB, and NOB microorganisms. Overall, 80% of the calibrated data fit the measured data. Stage 1 of the dynamic calibration showed NO2 and NO3 values close to 240 mg/L and 100 mg/L, respectively. Stage 2 showed NH4 values of 200 mg/L at day 30 with the calibrated effluent NO2 and NO3 value of 250 mg/L. In stage 3, effluent NH4 concentration was 200 mg/L at day 60.

A high-rate and stable nitrogen removal from reject water in a full-scale two-stage AMX® system.

This paper reports long-term performance of a two-stage AMX® system with a capacity of 70 m3/d treating actual reject water. An air-lift granulation reactor performed partial nitritation (PN-AGR) at an average nitrogen loading rate (NLR) of 3.1 kgN/m3-d, producing an average effluent NO2--N/NH4+-N ratio of 1.04. The average nitrogen removal rate of the system was 3.91 kgN/m3-d following an anaerobic ammonium oxidation (Anammox) stage moving bed biofilm reactor (A-MBBR). Although the total nitrogen concentrations in the reject water fluctuated seasonally, overall nitrogen removal efficiency (NRE) of the two-stage AMX® system was very stable at over 87%. The two-stage AMX® system, consisting of a PN-AGR followed by an A-MBBR, operated at a stable NLR of 1.86 kgN/m3-d (1.64 kgN/m3-d including the intermediate tank), which is 1.8 times higher (1.6 times including the intermediate tank) than other commercialized single-stage partial nitritation/Anammox (PN/A) processes (which operate at a NLR of about 1 kgN/m3-d). The PN-AGR was affected by high influent total suspended solids (TSS) loads, but was able to recover within a short period of 4 days, which confirmed that the two-stage PN/A process is resilient to TSS load fluctuations.

Saline conditions effect on the performance and stress index of anaerobic ammonium oxidizing (anammox) bacteria.

In this study, a lab-scale sequencing batch reactor dominated by freshwater anammox bacteria (FAB) was used to study the performance and stress index of the anammox bacteria at various saline conditions. The reactor with an effective volume of 1.8 L was operated for about 160 days. The nitrogen-loading rate was maintained at 0.364 kg-N m-3d-1 throughout the operational period. At the start-up phase, the seed biomass acclimation to the lab bioreactor showed an inconsistent performance. However, a stable performance was observed after day 38. The average substrate removal efficiency was 92% during most of the operational period. Anammox stress index; a ratio of dissolved Adenosine Triphosphate (dATPamx) to total Adenosine Triphosphate (tATPamx) showed an irrefutable correlation between NaCl concentration, anammox stress and microbial community. A drop in the biomass cellular ATP at 5 g L-1 salinity led to a significant decrease in the Specific Anammox activity. Candidatus Brocadia was identified as the main anammox species and its relative abundance reduced along the stepwise salinity increment.

Quality properties of various dietary fibers as isolated soy protein (ISP) replacements in pork emulsion systems.

This study aimed to investigate the possibility of replacing the isolated soy protein (ISP) as a binding agent for wheat, oat, and bamboo shoot dietary fibers. Dietary fibers and ISP were added to manufacturing process of pork emulsion, respectively, for investigate quality properties. Moisture contents of pork emulsion added wheat fiber-treated group was significantly higher than ISP-treated group (p < 0.05), and protein contents of dietary fiber-treated group were significantly lower than ISP-treated group (p < 0.05). Raw pork emulsion CIE a* value of oat, bamboo shoot fiber-treated group were significantly lower than ISP-treated group (p < 0.05). After cooking pork emulsion CIE L* value of dietary fiber-treated group were significantly higher than ISP-treated group (p < 0.05). Raw pork emulsion water holding capacity (WHC) of wheat, oat fiber-treated group were significantly higher than ISP-treated group (p < 0.05), and cooked pork emulsion WHC of wheat, bamboo shoot fiber-treated group were higher than ISP-treated group (p < 0.05). Cooking loss of ISP-treated group was significantly higher than dietary fiber-treated group (p < 0.05), and viscosity of ISP-treated group was lower than dietary fiber-treated group. Hardness of ISP-treated group was significantly lower than dietary fiber-treated group (p < 0.05); however, cohesiveness of ISP-treated group was significantly higher than dietary fiber-treated group (p < 0.05). In conclusion, dietary fiber added as binding agent to manufacturing process of pork emulsion was suitable to replacing ISP.

ANTI-VIRAL EFFECT OF HERBAL MEDICINE KOREAN TRADITIONAL CYNANCHUM PANICULATUM (BGE.) KITAG EXTRACTS.

BACKGROUND: Pestiviruses in general, and Bovine Viral Diarrhea (BVD) in particular, present several potential targets for directed antiviral therapy. MATERIAL AND METHODS: The antiviral effect of Cynanchum paniculatum (Bge.) Kitag (Dog strangling vine: DS) extract on the bovine viral diarrhea (BVD) virus was tested. First, a cytotoxicity test in MDBK (Madin-Darby bovine kidney) cells was done with all organic extract concentrations. RESULTS: The cytotoxic concentration CC50 for the ethyl acetate (EA) extracts was 18.2 ug/ml. In the tissue culture, infectious dose (TCID50) assay, the BVD virus decreased when treated with 18.2 ug/ml of the ethyl acetate extracts. CONCLUSION: Ethyl acetate extracts and fractions of the DS extract could be used as a potential antiviral for BVD.

Enhanced fluorescent resonant energy transfer of DNA conjugates complexed with surfactants and divalent metal ions.

Dimerization and resultant quenching of donor and acceptor dyes conjugated on DNA causes loss of fluorescent resonant energy transfer (FRET) efficiency. However, when complexed with surfactants and divalent metal ions, sheathing effects insulate and shield the DNA structures, reducing dimerization and quenching which leads to significant enhancement of FRET efficiency.

CTAB enhancement of FRET in DNA structures.

The effect of cetyl-trimethylammonium bromide (CTAB) on enhancing the fluorescence resonance energy transfer (FRET) between two dye-conjugated DNA strands was studied using fluorescence emission spectroscopy and dynamic light scattering (DLS). For hybridized DNA where one strand is conjugated with a TAMRA donor and the other with a TexasRed acceptor, increasing the concentration of CTAB changes the fluorescence emission properties and improves the FRET transfer efficiency through changes in the polarity of the solvent, neutralization of the DNA backbone and micelle formation. For the DNA FRET system without CTAB, the DNA hybridization leads to contact quenching between TAMRA donor and TexasRed acceptor producing reduced donor emission and only a small increase in acceptor emission. At 50 µM CTAB, however, the sheathing and neutralization of the dye-conjugated dsDNA structure significantly reduces quenching by DNA bases and dye interactions, producing a large increase in FRET efficiency, which is almost four fold higher than without CTAB.

An Aqueous Single Reactor Arc Discharge Process for the Synthesis of Graphene Nanospheres.

Using an aqueous single reactor arc discharge process with oil-in-water emulsions allows production of 2D multilayered graphenes (MLGs and 3D graphene-based crumpled/sphere-like particles with low levels of defects). The confinement forces to create 3D particles from 2D MLGs are estimated to be 2.5 µN for crumpled particles and 70 µN for spherical hollow particles.

Antifungal Action of Ginkgo biloba Outer Seedcoat on Rice Sheath blight.

From study of antifungal actions on the rice sheath blight by using the extract of Ginkgo biloba outer seedcoats, we found that the extracts of Ginkgo biloba outer seedcoats of all treatment concentrations had inhibited the rice sheath blight. Among them, the most effective concentration was 250 mg/l at which the growth of microbe was 26 mm and even at the packaging test, when sprayed the G. biloba outer seedcoats at the level of 250 mg/l, the damage rate of the rice sheath blight was identified as 13%. As a result investigating the antifungal activity by separating polysaccharides from G. biloba outer seedcoats, it showed that the clear zone of 14 mm or more was formed at the concentration of 250 mg/l or higher. Based on these results, we concluded that the G. biloba outer seedcoat is a natural substance with the antifungal activity on the rice sheath blight.

Saikosaponin D isolated from Bupleurum falcatum inhibits selectin-mediated cell adhesion.

Three saikosaponins were isolated from the MeOH extract of the roots of Bupleurum falcatum L.: saikosaponins B3 (1); B4 (2); and D (3). Of the three, compound 3 inhibited the interaction of selectins (E, L, and P) and THP-1 cells with IC50 values of 1.8, 3.0 and 4.3 µM, respectively. Also, the aglycone structure 4 of compound 3 showed moderate inhibitory activity on L-selectin-mediated cell adhesion. From these results, we suspect that compound 3 isolated from Bupleurum falcatum roots would be a good candidate for therapeutic strategies to treat inflammation.

High-yielding and photolabile approaches to the covalent attachment of biomolecules to surfaces via hydrazone chemistry.

The development of strategies to couple biomolecules covalently to surfaces is necessary for constructing sensing arrays for biological and biomedical applications. One attractive conjugation reaction is hydrazone formation--the reaction of a hydrazine with an aldehyde or ketone--as both hydrazines and aldehydes/ketones are largely bioorthogonal, which makes this particular reaction suitable for conjugating biomolecules to a variety of substrates. We show that the mild reaction conditions afforded by hydrazone conjugation enable the conjugation of DNA and proteins to the substrate surface in significantly higher yields than can be achieved with traditional bioconjugation techniques, such as maleimide chemistry. Next, we designed and synthesized a photocaged aryl ketone that can be conjugated to a surface and photochemically activated to provide a suitable partner for subsequent hydrazone formation between the surface-anchored ketone and DNA- or protein-hydrazines. Finally, we exploit the latent functionality of the photocaged ketone and pattern multiple biomolecules on the same substrate, effectively demonstrating a strategy for designing substrates with well-defined domains of different biomolecules. We expect that this approach can be extended to the production of multiplexed assays by using an appropriate mask with sequential photoexposure and biomolecule conjugation steps.

Long-term observation of the mineral trioxide aggregate extrusion into the periapical lesion: a case series.

One-step apexification using mineral trioxide aggregate (MTA) has been reported as an alternative treatment modality with more benefits than the use of long-term calcium hydroxide for teeth with open apex. However, orthograde placement of MTA is a challenging procedure in terms of length control. This case series describes the sequence of events following apical extrusion of MTA into the periapical area during a one-step apexification procedure for maxillary central incisor with an infected immature apex. Detailed long-term observation revealed complete resolution of the periapical radiolucent lesion around the extruded MTA. These cases revealed that direct contact with MTA had no negative effects on healing of the periapical tissues. However, intentional MTA overfilling into the periapical lesion is not to be recommended.

A real-time monitoring and assessment method for calculation of total amounts of indoor air pollutants emitted in subway stations.

UNLABELLED: Subway systems are considered as main public transportation facility in developed countries. Time spent by people in indoors, such as underground spaces, subway stations, and indoor buildings, has gradually increased in the recent past. Especially, operators or old persons who stay in indoor environments more than 15 hr per day usually influenced a greater extent by indoor air pollutants. Hence, regulations on indoor air pollutants are needed to ensure good health of people. Therefore, in this study, a new cumulative calculation method for the estimation of total amounts of indoor air pollutants emitted inside the subway station is proposed by taking cumulative amounts of indoor air pollutants based on integration concept. Minimum concentration of individual air pollutants which naturally exist in indoor space is referred as base concentration of air pollutants and can be found from the data collected. After subtracting the value of base concentration from data point of each data set of indoor air pollutant, the primary quantity of emitted air pollutant is calculated. After integration is carried out with these values, adding the base concentration to the integration quantity gives the total amount of indoor air pollutant emitted. Moreover the values of new index for cumulative indoor air quality obtained for 1 day are calculated using the values of cumulative air quality index (CAI). Cumulative comprehensive indoor air quality index (CCIAI) is also proposed to compare the values of cumulative concentrations of indoor air pollutants. From the results, it is clear that the cumulative assessment approach of indoor air quality (IAQ) is useful for monitoring the values of total amounts of indoor air pollutants emitted, in case of exposure to indoor air pollutants for a long time. Also, the values of CCIAI are influenced more by the values of concentration of NO2, which is released due to the use of air conditioners and combustion of the fuel. The results obtained in this study confirm that the proposed method can be applied to monitor total amounts of indoor air pollutants emitted, inside apartments and hospitals as well. IMPLICATIONS: Nowadays, subway systems are considered as main public transportation facility in developed countries. Time spent by people in indoors, such as underground spaces, subway stations, and indoor buildings, has gradually increased in the recent past. Especially, operators or old persons who stay in the indoor environments more than 15 hr per day usually influenced a greater extent by indoor air pollutants. Hence, regulations on indoor air pollutants are needed to ensure good health of people. Therefore, this paper presents a new methodology for monitoring and assessing total amounts of indoor air pollutants emitted inside underground spaces and subway stations. A new methodology for the calculation of cumulative amounts of indoor air pollutants based on integration concept is proposed. The results suggest that the cumulative assessment approach of IAQ is useful for monitoring the values of total amounts of indoor air pollutants, if indoor air pollutants accumulated for a long time, especially NO2 pollutants. The results obtained here confirm that the proposed method can be applied to monitor total amounts of indoor air pollutants emitted, inside apartments and hospitals as well.

Facile thermal treatment process for assembling vertically aligned semiconductor nanorods in solution.

Large-area films of vertically-aligned semiconductor nanorods have the potential to be useful, active materials for optoelectronic devices. We demonstrate here a highly facile thermal annealing approach for reversibly assembling 28 nm long CdSe nanorods into vertically aligned arrays in solution. Using temperature to control solvent strength, aggregated nanorods in a marginally poor solvent mixture were first dispersed at elevated temperatures and then reassembled into freely suspended, ordered sheets of aligned nanorods up to 24 µm in diameter upon slow cooling. The assembly method was tolerant of nanorod polydispersity and was effective over a wide range of solvents and nanorod concentrations. The pre-assembled nanorods could be directly drop-cast from solution onto a substrate and rapidly dried to obtain a film of vertically aligned nanorods.

In vitro evaluation of bacterial leakage resistance of an ultrasonically placed mineral trioxide aggregate orthograde apical plug in teeth with wide open apexes: a preliminary study.

OBJECTIVE: The purpose of this study was to compare the sealing ability of an ultrasonically placed orthograde mineral trioxide aggregate (MTA) apical plug in open apices. STUDY DESIGN: Thirty extracted human maxillary incisors were used. Experimental teeth were instrumented up to #100 file at the apex, and the 5 mm MTA apical barrier was placed with (group A; n = 11) or without (group B; n = 11) ultrasonic activation. Eight teeth served as control group. Bacterial leakage was assessed daily for 180 days using a double-chamber bacterial leakage model with Enterococcus faecalis. The results were analyzed with Fisher exact test. RESULTS: After 60 days, the ratio of leaked samples showed significant difference between groups A (2 out of 10) and B (8 out of 11) (P < .05). The mean time elapsed before leakage showed significant difference between groups A (158 days) and B (23 days) (P < .05). CONCLUSIONS: Ultrasonically placed orthograde MTA apical plugs were effective at delaying bacterial leakage.

Immediate implant placement into infected and noninfected extraction sockets: a pilot study.

OBJECTIVE: This study compared the osseointegration of immediate implants in dogs in infection-free sites and in sites with periradicular lesions which were removed by simulated periradicular surgery. STUDY DESIGN: Periradicular surgeries were performed to remove intentionally induced periradicular lesions, followed by teeth extraction and immediate implant placement with (experimental group 1) or without (experimental group 2) membranes. In the control group, implants were placed at healthy extraction sockets. After 12 weeks, the animals were killed and the results of histomorphometric study were analyzed by Kruskal-Wallis test. RESULTS: Both the control and the experimental implants were clinically acceptable. The control group showed significantly higher bone-implant contact (BIC; 76.03 +/- 7.98%) than the experimental groups 1 (59.55 +/- 14.21%) and 2 (48.62 +/- 20.22%) (P < .05). CONCLUSIONS: Despite the lower BIC of the experimental groups, this pilot study showed the possibility that immediate implant placement might be successful in extraction sockets with periradicular lesions. Further studies with larger sample sizes are required.