Multielemental determination of GEOTRACES key trace metals in seawater by ICPMS after preconcentration using an ethylenediaminetriacetic acid chelating resin

GEOTRACES is an international research project on marine biogeochemical cycles of trace elements and their isotopes. GEOTRACES key trace metals in seawater are Al (8-1000 ng/kg), Mn (4-300 ng/kg), Fe (1-100 ng/kg), Cu (30-300 ng/kg), Zn (3-600 ng/kg), and Cd (0.1-100 ng/kg), of which global oceanic distribution will be determined on a number of research cruises. This work introduces a novel method of solid-phase extraction to determine Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb in seawater by adjusting the pH of the sample to 6 and carrying out a single preconcentration step. The trace metals were collected from approximately 120 mL of seawater using a column of a chelating resin containing the ethylenediaminetriacetic acid functional group and eluted with approximately 15 mL of 1 M HNO3. Mn and Fe in the eluate were measured by inductively coupled plasma mass spectrometry (ICPMS) using the dynamic reaction cell mode, and the other metals were measured using the standard mode. Using this procedure, the trace metals were collected quantitatively, while >99.9% of alkali and alkaline earth metals in seawater were removed. The procedural blank was <7% of the mean concentration in deep ocean waters, except 16% for Pb. The overall detection limit was <14% of the mean concentration in deep ocean waters. The RSD was <9%. Our values for the trace metals in the certified reference materials of seawater NASS-5 and nearshore seawater CASS-4 agreed with the certified values (except that there is no certified value for Al). This method was also successfully applied to the reference materials of open-ocean seawater produced by the SAFe program. Our Fe concentrations were 5.9 +/- 0.7 ng/kg for surface water (S1) and 50.4 +/- 2.9 ng/kg for deep water (D2), which are in agreement with the interlaboratory averages of 5.4 +/- 2.4 and 50.8 +/- 9.5 ng/L, respectively. The data for other metals were oceanographically consistent.     

Efficient production of di- and tri-acylated mannosylerythritol lipids as glycolipid biosurfactants by Pseudozyma parantarctica JCM 11752(T)

Mannosylerythritol lipids (MELs) are one of the most promising biosurfactants known, because of their multifunctionality and biocompatibility. In order to attain an efficient production of MELs, Pseudozyma parantarctica JCM 11752(T), which is a newly identified strain of the genus, was examined for the productivity of MELs at different culture conditions. The yeast strain showed significant cell growth and production of di-acylated MELs even at 36 degrees C. In contrast, on conventional high-level MEL producers including P. rugulosa, the MEL yield considerably decreased with an increase of the cultivation temperature at over 30 degrees C. On P. parantarctica, soybean oil and sodium nitrate were the best carbon and nitrogen sources, respectively. Under the optimal conditions on a shake-flask culture at 34 degrees C, the amount of di-acylated MELs reached over 100 g/L by intermittent feeding of only soybean oil. Interestingly, the yeast strain produced tri-acylated MELs as well as di-acylated ones when grown on the medium containing higher soybean oil concentrations than 8% (vol/vol). The production of tri-acylated MELs was significantly accelerated at between 34 and 36 degrees C. With 20 % (vol/vol) of soybean oil at 34 degrees C, the yield of tri-acylated MELs reached 22.7 g/L. The extracellular lipase activity considerably depended on the culture temperature, and became the maximum at 34 degrees C; this would bring the accelerated production of tri-acylated MELs. Accordingly, the present strain of P. parantarctica provided high efficiency in MEL production at elevated temperatures compared to conventional MEL producers, and would thus be highly advantageous for the commercial production of the promising biosurfactants.     

Metal-free isotactic-specific radical polymerization of N-isopropylacrylamide with pyridine N-oxide derivatives: The effect of methyl substituents of pyridine N-oxide on the isotactic specificity and the proposed mechanism for the isotactic-specific radical polymerization

The radical polymerizations of N-isopropylacrylamide (NIPAAm) in chloroform at low temperatures in the presence of pyridine N-oxide (PNO) derivatives were investigated. It was found that the methylation at meta-positions of PNO improved the isotactic specificity induced by PNO, whereas the methylation at ortho-positions prevented the induction of the isotactic specificity. NMR analysis revealed that NIPAAm and PNO derivatives formed predominantly 2:1 complex through a hydrogen-bonding interaction. Furthermore, the induction of the isotactic specificity was attributed to the conformationally limited propagating radicals. Based on these findings, the mechanism of the isotactic-specific radical polymerization was discussed.     

Identification of an Angiotensin I-converting Enzyme Inhibitory Peptides from Protein Hydrolysates by a Soybean Protease and the Antihypertensive Effects of Hydrolysates in 4 Spontaneously Hypertensive Model Rats

ABSTRACT: Our previous study demonstrated that, because of its substrate specificity, protein hydrolysates by protease D3, which is originated from soybean, exhibited the prominent property of being less bitter than other enzymatic hydrolysates. In the 1st experiment in this series, angiotensin I-converting enzyme (ACE) inhibitory peptides from soy protein hydrolysate by D3 were identified by the establishment of a novel and effective peptide identification method. The amino acid sequences of candidate ACE inhibitory peptides were determined by electrospray ionization mass/mass spectrometry (MS/MS) analysis after rough purification of the samples with gel filtration chromatography and reverse-phase chromatography. Some of the candidate peptides had amino acid sequences that showed homology with those of the reported ACE inhibitory peptides. Then, 8 types of novel candidate peptides were synthesized according to a solid-phase method, and their ACE inhibitory activity was confirmed as the IC₅₀ value. The most potent inhibitor was NWGPLV (IC₅₀= 21 μ M ). In the 2nd experiment, the antihypertensive activity of protein hydrolysates by D3 was investigated in spontaneously hypertensive model rats (SHRs). The dose-dependent antihypertensive effect of soy protein hydrolysate was confirmed, and systolic blood pressure was significantly reduced after the oral administration of doses exceeding 100 mg/kg. Casein hydrolysate was found to have the most potent effects on suppressing blood pressure as well as ACE inhibitory activity among the various food protein hydrolysates studied because of the primary structure of casein. These results indicate that hydrolysates by D3 could be a useful food ingredient because it has the physiological function (antihypertensive activity).     

Pose Estimation of Construction Materials Using Multiple ID Devices for Parts and Packets Unification

Abstract: A method for characterizing the pose (position and orientation) of large objects using multiple identification (ID) devices, such as radio‐frequency identification (RFID) devices, is proposed. Simultaneous management of construction materials and their data using ID devices for construction automation has been proposed. In this management scheme, workers or robots (1) acquire the ID of a device using an ID reader, (2) obtain construction material data using the ID, and (3) use the data to perform various tasks. In this scheme, the object pose is crucial because it can be changed by robots and workers who do not possess an ID reader or have not measured the pose previously. The proposed method uses the geometric relationship between the ID device attached to the object and the ID reader, and is based on the relationship between the relative displacements of multiple ID devices. The position and direction of each ID device and ID reader are measured with respect to the object and reference coordinate frames, respectively. Experimental results proved the feasibility of our proposed method.     

Multiple Gaussian process models for direct time series forecasting

This paper focuses on the problem of time series forecasting using the Gaussian process models. The Gaussian process model is a nonparametric model and the output of the model has Gaussian distribution with mean and variance. The multiple Gaussian process models as every step ahead predictors are used for time series forecasting in accordance with the direct approach. The separable least‐squares approach that combines the genetic algorithm with the linear least‐squares method is applied to train these Gaussian process models. Simulation results are shown to illustrate the effectiveness of the proposed direct forecasting method. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Mechanism underlying specificity of proteins targeting inorganic materials

Adhesion force analysis using atomic force microscopy clearly revealed for the first time the mechanism underlying the specific binding between a titanium surface and ferritin possessing the sequence of Ti-binding peptide in its N-terminal domain. Our results proved that the specific binding is due to double electrostatic bonds between charged residue and surface groups of the substrate. Furthermore, it is also demonstrated that the accretion of surfactant reduces nonspecific interactions, dramatically enhancing the selectivity and specificity of Ti-binding peptide.