青柳 里果

Nanostructure evaluation is crucial for developing highly controlled nanomaterials. The titanate nanosheets with a lamellar mesostructure synthesized using a lamellar self-assembly of dodecanediamine (DDA) were evaluated with time-of-flight secondary ion mass spectrometry (TOF-SIMS) and gentle-SIMS (G-SIMS) to evaluate detailed chemical structures which have not been provided with transmission electron microscopy (TEM), X-ray diffraction, and ultraviolet-visible diffuse reflectance spectra analysis. Although TOF-SIMS is a useful method for evaluating complex organic and inorganic materials, it is often difficult to interpret TOF-SIMS spectra of complex samples due to complicated fragment ions. Therefore, G-SIMS, helpful for analyzing intricate TOF-SIMS spectra, was applied to extract important information of TOF-SIMS data. For example, molecular ions and more intact fragment ions are emphasized and found easily using G-SIMS. The layered titanate nanosheets sample produced using tetraisopropyl orthotitanate (TIPT), triethanolamine (TEOA), and DDA (TIPT + DDA + TEOA) and reference nanoparticle samples TIPT + DDA, TIPT + TEOA, and TIPT were prepared. As a result, titanate compounds and DDA molecular ions were only detected in TIPT + DDA + TEOA. Therefore, it is indicated that robust lamellar mesostructure of titanate compounds and DDA is produced by reactions related to TIPT, DDA, and TEOA. It is also suggested that organic metal materials which have large hydrocarbon groups can be analyzed using G-SIMS. Copyright (C) 2012 John Wiley & Sons, Ltd.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is powerful for providing chemical and spatial information. It is, however, often difficult to interpret TOF-SIMS data of complex samples such as tissues because of peak overlapping and unpredictable fragmentation of biomolecules, and therefore, data analysis techniques have been required to interpret TOF-SIMS data. In this study, multivariate curve resolution (MCR), extracting pure component spectra from original data containing mixed information of all materials in a sample, was applied to TOF-SIMS data of white radish sprouts to investigate physiological phenomena in the plant by comparing materials in the roots under different conditions in terms of magnetic fields. Influence of magnetic fields on plant growth was reported, but the mechanism has not been clarified. The sliced root samples were measured with TOF-SIMS using Au+, and then, the TOF-SIMS data were analyzed using MCR. As a result, the tissue area was distinguished from the others such as the substrate and compounds used for sample preparation by means of MCR, and the spectra of the components related to the tissue were obtained. Secondary ions specific to the sample, under a particular condition of magnetic fields, were suggested by analyzing the spectra of the tissue-related components. It is indicated that it is useful to apply MCR into TOF-SIMS spectra and secondary ion images to extract less complex spectra from intricate tissue samples. Copyright (C) 2012 John Wiley & Sons, Ltd.

In terms of the development of new medicines, the identification of peptides in organs and tissues is crucial. Because time-of-flight secondary ion mass spectrometry (TOF-SIMS) has extremely high sensitivity and does not require a special pretreatment of samples, it is one of the most promising analysis techniques for evaluation of unknown peptides in organ extract. It is, however, often difficult to interpret TOF-SIMS spectra of biomolecules because of the overlap of fragment ions from biomolecules and organic molecules and the difficulty for identifying high mass secondary ions. Therefore, appropriate data analysis methods such as G-SIMS and multivariate analysis are necessary to characterize intricate TOF-SIMS spectra. In this study, G-SIMS was applied to interpret TOF-SIMS spectra of peptide samples. As a result, molecular ions of two peptides, approximately 400 molecular weight, were indicated automatically using G-SIMS analysis without preinformation on the tested peptides. Copyright © 2012 John Wiley &amp Sons, Ltd. Copyright © 2012 John Wiley &amp Sons, Ltd.

In terms of the development of new medicines, the identification of peptides in organs and tissues is crucial. Because time-of-flight secondary ion mass spectrometry (TOF-SIMS) has extremely high sensitivity and does not require a special pretreatment of samples, it is one of the most promising analysis techniques for evaluation of unknown peptides in organ extract. It is, however, often difficult to interpret TOF-SIMS spectra of biomolecules because of the overlap of fragment ions from biomolecules and organic molecules and the difficulty for identifying high mass secondary ions. Therefore, appropriate data analysis methods such as G-SIMS and multivariate analysis are necessary to characterize intricate TOF-SIMS spectra. In this study, G-SIMS was applied to interpret TOF-SIMS spectra of peptide samples. As a result, molecular ions of two peptides, approximately 400 molecular weight, were indicated automatically using G-SIMS analysis without preinformation on the tested peptides. Copyright © 2012 John Wiley &amp Sons, Ltd. Copyright © 2012 John Wiley &amp Sons, Ltd.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is powerful for providing chemical and spatial information. It is, however, often difficult to interpret TOF-SIMS data of complex samples such as tissues because of peak overlapping and unpredictable fragmentation of biomolecules, and therefore, data analysis techniques have been required to interpret TOF-SIMS data. In this study, multivariate curve resolution (MCR), extracting pure component spectra from original data containing mixed information of all materials in a sample, was applied to TOF-SIMS data of white radish sprouts to investigate physiological phenomena in the plant by comparing materials in the roots under different conditions in terms of magnetic fields. Influence of magnetic fields on plant growth was reported, but the mechanism has not been clarified. The sliced root samples were measured with TOF-SIMS using Au+, and then, the TOF-SIMS data were analyzed using MCR. As a result, the tissue area was distinguished from the others such as the substrate and compounds used for sample preparation by means of MCR, and the spectra of the components related to the tissue were obtained. Secondary ions specific to the sample, under a particular condition of magnetic fields, were suggested by analyzing the spectra of the tissue-related components. It is indicated that it is useful to apply MCR into TOF-SIMS spectra and secondary ion images to extract less complex spectra from intricate tissue samples. Copyright (C) 2012 John Wiley & Sons, Ltd.

Nanostructure evaluation is crucial for developing highly controlled nanomaterials. The titanate nanosheets with a lamellar mesostructure synthesized using a lamellar self-assembly of dodecanediamine (DDA) were evaluated with time-of-flight secondary ion mass spectrometry (TOF-SIMS) and gentle-SIMS (G-SIMS) to evaluate detailed chemical structures which have not been provided with transmission electron microscopy (TEM), X-ray diffraction, and ultraviolet-visible diffuse reflectance spectra analysis. Although TOF-SIMS is a useful method for evaluating complex organic and inorganic materials, it is often difficult to interpret TOF-SIMS spectra of complex samples due to complicated fragment ions. Therefore, G-SIMS, helpful for analyzing intricate TOF-SIMS spectra, was applied to extract important information of TOF-SIMS data. For example, molecular ions and more intact fragment ions are emphasized and found easily using G-SIMS. The layered titanate nanosheets sample produced using tetraisopropyl orthotitanate (TIPT), triethanolamine (TEOA), and DDA (TIPT + DDA + TEOA) and reference nanoparticle samples TIPT + DDA, TIPT + TEOA, and TIPT were prepared. As a result, titanate compounds and DDA molecular ions were only detected in TIPT + DDA + TEOA. Therefore, it is indicated that robust lamellar mesostructure of titanate compounds and DDA is produced by reactions related to TIPT, DDA, and TEOA. It is also suggested that organic metal materials which have large hydrocarbon groups can be analyzed using G-SIMS. Copyright (C) 2012 John Wiley & Sons, Ltd.

RATIONALE Secondary ion mass spectrometry (SIMS) is an important technique for the characterization of proteins at surfaces. However, interpretation of the mass spectra is complicated owing to confusion with peaks from contaminants and the substrate which is further compounded by complex fragmentation mechanisms. We test a new development of the G-SIMS method called the g-ogram to separate out spectral components without a priori information about which peaks to include in the analysis and which peaks relate to each component. METHODS The effectiveness of the g-ogram method is investigated using a model system of lysozyme adsorbed onto a silicon wafer and indium tin oxide substrates. In the method, two SIMS spectra are acquired using Bi+ and Mn+ primary ions which create lower and higher fragmentation in the spectra, respectively. The g-ogram separates out components using a separation parameter that is related to the fragmentation energy. RESULTS The g-ogram separates the spectrum of lysozyme adsorbed onto a silicon wafer into three components: (i) the substrate and PDMS contamination; (ii) a second, but unexpected, contaminant; and (iii) peaks from the protein amino acids. Similar results are achieved for the indium tin oxide substrate. In addition, evidence of fragments from plural amino acids with two candidate peaks at 140.12 Da and 185.08 Da is observed. CONCLUSIONS The g-ogram method effectively separates out mass peaks relating to the substrate, contamination and protein without any a priori information or subjective decisions about which peaks to include in the analysis (so called 'peak picking'). This is a great help to analysts. We find two possible peaks from plural amino acids but no evidence of pluralities is found for peaks above 240 Da that are generated from when using Bi or Mn primary ions. Copyright (C) 2012 John Wiley & Sons, Ltd.

Components on the outermost hair surface were directly analyzed with time-of-flight secondary ion mass spectrometry (TOF-SIMS). The depth profiling of characteristic amino acid components in hair surfaces was performed using a Bi 3 ++ analysis beam combined with a C 60 ++ sputtering beam. The depth analysis of a protein bilayer model of zein and casein layers indicated that the damage caused by C 60 ++ sputtering did not influence the TOF-SIMS analysis, therefore, the C60 sputtering is considered to be feasible at an analysis depth of 2 μm from the surface. The depth profiling analysis data for hair surfaces showed oscillating changes in the peak intensities of amino acid fragments, and this phenomenon is considered to reflect the multilayer structure of cuticle tissue. Focusing on the first layer of cuticle tissue, the depth profiling change of the cysteine/cystine-related fragment corresponding to the A-layer, exocuticle and endocuticle of cuticle tissue was consistent with the TEM result. Furthermore, a comparison of the depth profiling data from before and after the bleaching treatment revealed that the cysteine/cystine-related peak intensity was high at the outermost surface because the layer was cysteine-rich for bonding the lipid layer. As a result, the existence of a thin protein layer with specific amino acid components, known as the epicuticle, was suggested. The depth profiling analysis of protein using TOF-SIMS provides significant information for investigating the structure and functions of the surface of human hair. © 2012 The Surface Science Society of Japan.

The outermost surface of the human hair is covered with a thin layer of fatty acids bonding proteins, which plays an important role in giving hair a soft and smooth feeling and surface hydrophobicity. In this study, changes in fatty acids and protein fragment ions were characterized using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) to investigate hair damage. As a result, the intensity of the fragment ion m/z 76 related to cystine and cysteine, major components of hair keratin, decreased with the hair damage, which is consistent with generation of cysteic acid caused by oxidative cleavage of both thioester bond in the fatty acids and disulfide bond of cystine. Thus, it is indicated that hair damage can be evaluated by measuring m/z 76. Furthermore, 18-methyleicosanoic acid, the major component of the fatty acids, decreased rapidly in three bleaching processes, and the peak at m/z 76 also decreased correspondingly. These results suggest that the oxidative cleavage of thioester bonds in the fatty acids is the major change caused by the bleaching process. Copyright (c) 2011 John Wiley & Sons, Ltd.

Chemical imaging and depth profiling of skin is useful for studying various biological phenomena. Although secondary ion images of biomolecules such as phosphocholine and cholesterol distributions on skin samples are easily obtained with time-of-flight secondary ion mass spectrometry (TOF-SIMS), the observation of proteins or minor ingredients is often difficult. In this study, TOF-SIMS imaging data of skin samples were analyzed with multivariate curve resolution (MCR) to obtain information on reagents applied to the middorsal skin of mice. The skin was sliced with a cryostat and placed on indium-tin oxide glass plates. The samples were measured with TOF-SIMS using Bi3++, and then the obtained data were analyzed with MCR. As a result, distributions of secondary ions related to the reagents were suggested by MCR results, although they were not obtained by a manual analysis using respective peaks. Copyright (c) 2012 John Wiley & Sons, Ltd.

The investigation of fragment ions from macromolecules is crucial for the interpretation of time-of-flight secondary ion mass spectrometry (TOF-SIMS) data, although it is often difficult because fragmentation mechanisms in secondary ion mass spectrometry have not been clarified. In this study, multivariate curve resolution (MCR) was applied to extract a pure component spectrum, and gentle SIMS (G-SIMS) was applied to the investigation of fragment ions from polymers. Several types of polyethylene glycol were diluted in toluene solutions, and then thin films of them were formed on Si wafers using a spin coater. The samples were measured with TOF-SIMS using Mn+, Bi+, and Bi3+ and then the TOF-SIMS spectra data were analyzed with G-SIMS and MCR. As a result, relationships between fragment ions were clarified using G-SIMS, and a pure sample spectrum of each polyethylene glycol sample was extracted by MCR. Copyright (c) 2012 John Wiley & Sons, Ltd.

Chemical imaging and depth profiling of skin is useful for studying various biological phenomena. Although secondary ion images of biomolecules such as phosphocholine and cholesterol distributions on skin samples are easily obtained with time-of-flight secondary ion mass spectrometry (TOF-SIMS), the observation of proteins or minor ingredients is often difficult. In this study, TOF-SIMS imaging data of skin samples were analyzed with multivariate curve resolution (MCR) to obtain information on reagents applied to the middorsal skin of mice. The skin was sliced with a cryostat and placed on indium-tin oxide glass plates. The samples were measured with TOF-SIMS using Bi3++, and then the obtained data were analyzed with MCR. As a result, distributions of secondary ions related to the reagents were suggested by MCR results, although they were not obtained by a manual analysis using respective peaks. Copyright (c) 2012 John Wiley & Sons, Ltd.

The investigation of fragment ions from macromolecules is crucial for the interpretation of time-of-flight secondary ion mass spectrometry (TOF-SIMS) data, although it is often difficult because fragmentation mechanisms in secondary ion mass spectrometry have not been clarified. In this study, multivariate curve resolution (MCR) was applied to extract a pure component spectrum, and gentle SIMS (G-SIMS) was applied to the investigation of fragment ions from polymers. Several types of polyethylene glycol were diluted in toluene solutions, and then thin films of them were formed on Si wafers using a spin coater. The samples were measured with TOF-SIMS using Mn+, Bi+, and Bi3+ and then the TOF-SIMS spectra data were analyzed with G-SIMS and MCR. As a result, relationships between fragment ions were clarified using G-SIMS, and a pure sample spectrum of each polyethylene glycol sample was extracted by MCR. Copyright (c) 2012 John Wiley & Sons, Ltd.

Interpretation of fragment ions of complex samples such as bio samples and polymer mixed samples obtained with time-of-flight secondary ion mass spectrometry (TOF-SIMS) is often difficult because of overlapping of fragment ions. Molecular ions or large fragment ions in TOF-SIMS spectra are often hidden among strong peaks of secondary ions. Since G-SIMS, which has been developed to investigate secondary ions in detail, enhances molecular ions and more intact fragment ions, and therefore it is useful to interpret intricate sample spectra. In this study, G-SIMS was applied to a thin film of polyethylene (average molecular weight : 540-640) on Si substrate in order to investigate effectiveness of G-SIMS on polymer samples. As a result, G-SIMS spectra enhancing molecular ions and more intact fragment ions were obtained and indicate relationship between particular fragment ions, which is useful to interpret TOF-SIMS spectra.

Fragment ion analysis of protein samples is crucial for structural evaluation of proteins. Interpretation of fragment ions from bioplolymers, however, is often difficult because fragmentation mechanisms in secondary ion mass spectrometry have not been clarified. Therefore employment of chemometrics is necessary to obtain detailed information from time-of-flight secondary ion mass spectrometry (TOF-SIMS) data of complex samples. In this study, multivariate curve resolution (MCR) was applied to extract a pure component spectrum from a TOF-SIMS spectrum which contains mixed materials information. The model biopolymer, chicken egg white lysozyme was immobilized on a gulutaraldehyde-activated aminosilanized indium-tin oxide (ITO) glass plate by covalent bonding. A reference sample such as substrates without the protein were prepared. All samples were measured with TOF-SIMS using Bi3+, and then the TOF-SIMS spectra data were analyzed using MCR with and without data preprocessing. As a result, images and spectra related to each material in the sample were obtained by MCR. The fragment ions in the extracted spectra are consistence with chemical information of each material.

Chemical mapping of biomolecules in biological samples such as tissues and cells is crucial for biological, medical and biochemical fields. Although secondary ion images of biomolecules such as phosphocholine and cholesterol distributions on tissue samples are easily obtained with time-of-flight secondary ion mass spectrometry (TOF-SIMS), the observation of minor ingredients is often difficult. In this study TOF-SIMS imaging data of skin samples were analyzed with a multivariate analysis technique, multivariate curve resolution (MCR), in order to investigate appropriate analysis conditions. Mice middorsal skin was sliced with a microtome and placed on indium-tin oxide glass plates. The samples were measured with TOF-SIMS using Bi3+, and then the obtained data were analyzed with MCR under various analysis conditions for investigating appropriate conditions. As a result, it is indicated that MCR classify TOF-SIMS raw data into some categories representing different features, which makes interpretation of TOF-SIMS data easier.

Maize, a staple food crop in Malawi in sub-Sahara region has been grown under rainfed conditions for many years but many factors affect its production. Changing rainfall pattern has been a main factor which is believed to have come about due to the changing climate in recent years. A case study of over 60 years of rainfall data in Malawi's central region was analyzed where rainfall data over time was compared with maize production yields. Other non-climatic factors were also studied to explain their impact on production. Both observed monthly and daily rainfall data were used. Thiessen polygon method was used to calculate daily areal rainfall from the available 4 gauging stations. Since the gauging network was not adequate a regression analysis of the areal rainfall against the recorded time series from the stations was carried out. A regression equation created from the station with highest correlation was used to predict the daily rainfall data which was analyzed in detail to identify daily pattern changes. It was found that rainfall distribution characteristics have changed over time becoming more unpredictable and, hence, reducing production. In general, everytime there was an erratic rainfall pattern, maize production was affected. The paper recommends building more sustainable irrigation systems so that agricultural production can be under control during droughts. It also recommends removing policy that depends on rainfed food production and economic activities to control the problems associated with the changing rainfall pattern.

Recently, the biomaterial field has become one of the most important applications of time of flight (TOF) SIMS time-of-flight secondary ion mass specmetry (TOF-SIMS). Although TOF-SIMS can be applied to insulating samples, electrically conductive substrates such as Si, Auplates and indium-tin oxide (ITO) glass plates are more useful to detect fragment ions from biomaterials. ITO glass and silicon substrates are often employed for the preparation of biomaterial samples instead of glass plates. In this study, an ITO glass plate and silicon plates with various thicknesses of silicon oxide thin film were compared to investigate the most suitable sample preparation conditions for evaluating protein samples using TOF-SIMS. Four kinds of substrates, an ITO glass plate, a silicon plate, a silicon plate with an oxide film of 50 nm, and another of 250 nm, were employed as substrates to adsorb a model protein, egg white lysozyme. Each sample was measured five times with TOF-SIMS with a gallium ion source under static conditions. The TOF-SIMS spectra of each sample were compared to evaluate the effect of thin oxide films on protein measurement with TOF-SIMS. The specific peaks of each sample related to lysozyme in the positive ion spectra were selected in comparison to their control samples. As a result, TOF-SIMS spectra of the silicon plate with a 50 nm silicon oxide film showed the most specific peaks related to lysozyme. In addition, TOF-SIMS spectra of the ITO sample showed many peaks of fragment ions related to lysozyme in a high-mass range at which the other samples do not show adequate peaks. Thus, both substrates with the oxide films, silicon oxide and ITO, displayed better results than the silicon plate sample. Copyright (C) 2010 John Wiley & Sons, Ltd.

Gas cluster (GC) ion sources, such as an argon cluster source, have been employed in SIMS of organic or biomaterials due to their low-energy projectile effect. Recently, it was found that GC-SIMS reportedly provides intact ion detection of proteins with molecular weights of 10000 or higher. Since GC-SIMS enables control of the gas cluster size and collision energy per atom, it is considered sensitive for the detection of very small differences in the monolayers of polypeptides such as leu-enkephalin (H-Tyr-Gly-Gly-Phe-Leu-OH) and met-enkephalin (H-Tyr-Gly-Gly-Phe-Met-OH). In this study, both enkephalins were measured with GC-SIMS and their spectra were compared to evaluate GC-SIMS sensitivity to small chemical structure differences. The polypeptides, leu-enkephalin and met-enkephalin, were immobilized on indium-and tin oxide (ITO)-coated glass plates, respectively, by binding their N terminal residues to glutaraldehyde-activated aminosilanized-ITO plates. An aminosilanized-ITO plate without polypeptide was also prepared as the control sample. After freeze-drying, the samples were measured with TOF-SIMS with the argon cluster ion source, and then TOF-SIMS spectra were analyzed to select peaks specific to the polypeptides. As a result, fragment ions related to the polypeptide without recombination were detected using the argon GC-SIMS. Copyright (C) 2010 John Wiley & Sons, Ltd.

TOF-SIMS is a promising technique for evaluating biodevices due to its ultrahigh surface sensitivity. Since a cluster ion source such as C(60)(+) provides low collision energy per atom, time-of-flight secondary ion mass spectrometry (TOF-SIMS) with the cluster ion is useful for detecting the uppermost surface of molecules immobilized on a substrate, and therefore, enables the evaluation of the orientation of these immobilized biomolecules. Effects of TOF-SIMS with C(60)(+) were investigated in this study. A relatively small protein, lysozyme, and polypeptides having five amino acid residues, Leu-enkephalin and Met-enkephalin, were employed as model samples. The protein and the polypeptides were immobilized on aminosilanized-indium-tin oxide (ITO) coated glass plates at their N-terminal residues by covalent bonding. The aminosilanized-ITO plate without protein or polypeptide was also prepared as a control sample. After freeze-drying, the samples were measured with TOF-SIMS using gallium and C(60)(+) cluster ion sources, and then TOF-SIMS spectra were analyzed to select peaks specific to each biomolecule by a comparison between the samples. As a result, the C(60)(+) primary ion source showed advantages in evaluating biomolecules, because more peaks at a higher mass generated from the biomolecules can be obtained using C(60)(+) than Ga(+) or Au(3)(+) as the primary ion source, although no difference was detected between the two polypeptide samples under the current measurement conditions. Copyright (C) 2010 John Wiley & Sons, Ltd.

A mild, efficient and LiCl-free synthetic method for indole derivatives based on the heteroannulation of alkynes with 2-iodoanilines was achieved using palladium on carbon (Pd/C) and NaOAc in heated NMP. The N-tosyl protection of 2-iodoaniline expedited the reaction progress, while other protecting groups, such as tert-butoxycarbonyl, acetyl, and benzyloxycarbonyl groups, underwent deprotection under the present conditions. A variety of di- and monosubstituted alkynes could effectively react with N-tosyl-2-iodoaniline to give the corresponding indoles in good to high yields.

The evaluation of orientation of biomolecules immobilized on nanodevices is crucial for the development of high performance devices. Such analysis requires ultra high sensitivity so as to be able to detect less than one molecular layer on a device. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has sufficient sensitivity to evaluate the uppermost surface structure of a single molecular layer. The objective of this study is to develop an orientation analysis method for proteins immobilized on nanomaterials such as quantum dot particles, and to evaluate the orientation of streptavidin immobilized on quantum dot particles by means of TOF-SIMS. In order to detect fragment ions specific to the protein surface, a monoatomic primary ion source (Ga(+)) and a cluster ion source (Au(3+)) were employed. Streptavidin-immobilized quantum dot particles were immobilized on aminosilanized ITO glass plates at amino groups by covalent bonding. The reference samples streptavidin directly immobilized on ITO plates were also prepared. All samples were dried with a freeze dryer before TOF-SIMS measurement. The positive secondary ion spectra of each sample were obtained using TOF-SIMS with Ga(+) and Au(3+), respectively, and then they were compared so as to characterize each sample and detect the surface structure of the streptavidin immobilized with the biotin-immobilized quantum dots. The chemical structures of the upper surface of the streptavidin molecules immobilized on the quantum dot particles were evaluated with TOF-SIMS spectra analysis. The indicated surface side of the streptavidin molecules immobilized on the quantum dots includes the biotin binding site. (C) 2009 Elsevier B.V. All rights reserved.

Fluorescence enhancement of fluorescein isothiocyanate-labeled protein A (FITC-protein A) caused by the binding with immunoglobulin G (IgG) in bovine plasma was studied. FITC-protein A was immobilized onto a glass surface by covalent bonds. An increase in fluorescence intensity was dependent on IgG concentration ranging from 20 to 78 mu g/mL in both phosphate buffer saline and bovine plasma. This method requires no separation procedure, and the reaction time is less than 15 min. A fluorescence enhancement assay by the affinity binding of fluorescence-labeled reagent is thus available for the rapid determination of biomolecules in plasma.

The evaluation of proteins on biodevices, such as the distribution or orientation of immobilized proteins, is one of the most important issues for the development of sophisticated biodevices. In this review, a description is provided of the application of one of the most sensitive surface analysis methods, time-of-flight secondary ion mass spectrometry (TOF-SIMS), to protein evaluation and TOF-SIMS spectra analysis using mutual information. TOF-SIMS is useful for the evaluation of biodevice surfaces, because TOF-SIMS provides submicron-scale chemical mapping and information on the chemical structures of the upper surface part of a protein. In addition, TOF-SIMS requires no pretreatment of samples, such as labeling with a fluorescent probe or coating with metallic thin films. Data analysis methods are, however, required to interpret the protein sample TOF-SIMS data, because the fragment ions from proteins are so complicated that it is difficult to predict them. In order to identify hidden important peaks related to protein samples out of the hundreds of peaks in TOF-SIMS spectra, mutual information has been used. Protein distribution on biodevices and the orientation of an immobilized protein obtained with this method are described in this review. Copyright (C) 2008 John Wiley & Sons, Ltd.

We previously reported a silica-binding protein, designated Si-tag, which can be used to immobilize proteins on silica surfaces. Here, we constructed a fusion protein of Si-tag and immunoglobulin-binding staphylococcal protein A for oriented immobilization of antibodies on a silicon wafer whose surface is oxidized to silicon dioxide (silica). The fusion protein, Si-tagged protein A, strongly bound to the silica surface with a dissociation constant of 0.31 nM. Time-of-flight secondary ion mass spectrometry analysis of the silicon wafer coated with Si-tagged protein A, combined with principal component analysis and mutual information, demonstrated that protein A is localized on the outermost surface of the bound protein layer. Immunoglobulin G (IgG) was immobilized both on the silicon wafer coated with Si-tagged protein A and, as a control, directly on the intact silicon wafer via physical adsorption. The silicon wafer coated with Si-tagged protein A bound 30-70% more IgG than the uncoated silicon wafer, whereas the antigen-binding activity was 4- to 5-fold higher for the former, indicating that IgG was functionally immobilized on the silicon wafer via Si-tagged protein A in an oriented manner. (C) 2008 Elsevier Inc. All rights reserved.

Malawi's agricultural sector is the main contributor to the national economy. Its activities are, however dependent on rainfed farming and it suffers from the consequences of poor policy implementation and management, as well. Irrigation has, for a long time, been viewed as a major component in agriculture but its implementation has been facing challenges and problems ever since the initiative was formally introduced. The status of irrigation farming in Malawi was studied based on four major national schemes selected based on their size, age and management, and implementation style. Ten study elements crucial in assessing performance of irrigation farming were identified and each studied in relation to the schemes. Each study site was examined within the context of these study elements to understand the core issues under study. The analyses showed that despite the abundance of water in the country, irrigation is still very dismally implemented making agricultural production low, causing serious household food insecurity and distorting the national economy. Some achievements have been made to stir the irrigation sector into a viable contributor to the agricultural sector; but it is still far from being a vibrant factor for a reliable production.

The evaluation of protein structural change is crucial for the study of protein-protein interactions and protein conformational changes. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to detect pH dependent structural change in staphylococcal protein A (SpA), which is well known to the bind Fc region of immunoglobulins. TOF-SIMS spectra of SpA-immobilized samples in a pH 7 solution, in an acidic solution, and in a pH 7 solution after having been soaked in an acidic solution, respectively, were compared to select fragment ions specific to normal SpA at pH 7 using spectral analysis techniques such as principal component analysis (PCA) and the mutual information method. A fragment ion depending on change in the B and E domains of SpA were detected with this method. These findings demonstrate that structural change of SpA depending on pH change can be evaluated with TOF-SIMS together with spectrum analysis methods for the multivariate data. [DOI: 10.1380/ejssnt.2009.715]

A simple, efficient, and environmentally-friendly heterogeneous Ru/C-catalyzed oxidation of secondary and primary alcohols without additives under an atmosphere of oxygen has been established.

A piece of tissue extracted from a chum salmon Oncorhynchus keta head was measured with time-of-flight secondary ion mass spectrometry (TOF-SIMS) in order to evaluate the distribution and composition of magnetic materials in the tissue, which may concern with geomagnetic navigation of long-distance migrating salmon. Several depositions of iron compounds were detected in the tissue by TOF-SIMS analysis. Comparing with total ion images providing a topological tissue structure, specific distribution of iron ion in the tissue was clearly shown. Higher magnification TOF-SIMS analysis revealed the existence of the aggregations of iron particles. Iron oxide clusters comprising many submicron particles were also detected in the tissue using scanning electron microscopy and X-ray analysis, suggesting the common existence of submicron-scale iron oxides in salmon heads. These results suggest that TOF-SIMS analysis is a valid method to clarify detailed structures and chemical properties of candidate magnetoreceptors in fish heads. (c) 2008 Elsevier B.V. All rights reserved.

The usefulness of the usage of cluster primary ion source together with an Ag substrate and detection of Ag cationized molecular ions was studied from the standpoint to realize high sensitivity TOF-SIMS analysis of organic materials. Although secondary ions from polymer thin films on a Si substrate can be detected in a higher sensitivity with Au(3)(+) cluster primary ion compared with Ga(+) ion bombardment, it was clearly observed that the secondary ion intensities from samples on an Ag substrate showed quite a different tendency from that on Si. When monoatomic primary ions, e. g., Au(+) and Ga(+), were used for the measurement of the sample on an Ag substrate, [M+Ag](+) ions (M corresponds to polyethylene glycol molecule) were detected in a high sensitivity. On the contrary, when Au(3)(+) was used, no intensity enhancement of [M+Ag](+) ions was observed. The acceleration energy dependence of the detected secondary ions implies the different ionization mechanisms on the different substrates. (C) 2008 Elsevier B. V. All rights reserved.

Orientation and three-dimensional structure of immobilized proteins on bio-devices are very important to assure their high performance. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is able to analyze upper surface of one layer of molecules. Orientation of immobilized proteins can be evaluated based on determination of a partial structure, representing ensemble of amino acids, on the surface part. In this study, a monolayer of cytochrome b5 was reconstituted onto gold substrate and investigated by surface plasmon resonance (SPR). After freeze-drying, the resulted protein self-assembly was evaluated using TOF-SIMS with the bismuth cluster ion source, and then TOF-SIMS spectra were analyzed to select peaks specific to cytochrome b5 and identify their chemical formula and ensembles of amino acids. The results from TOF-SIMS spectra analysis were compared to the amino acid sequence of the modified cytochrome b5 and three-dimensional structure of cytochrome b5 registered in the protein data bank. Finally, fragment-ion-generating parts of the immobilized-cytochrome b5 are determined based on the suggested residues and three-dimensional structure. These results suggest the actual structure and confirm the expected orientation of immobilized protein. (C) 2008 Elsevier B.V. All rights reserved.

Evaluation of immobilized-proteins on bio-devices is important for the development of sophisticated devices. Lysozyme molecules immobilized on substrates were evaluated by means of time-of-flight secondary ion mass spectrometry (TOF-SIMS). Two types of the lysozyme-immobilized samples were prepared by controlling the binding parts, i.e., the amino groups or carboxyl groups, of the protein. The TOF-SIMS spectra of each sample were analyzed with mutual information to select fragment ions specific to each sample. According to the results, differences between the samples being immobilized in the different ways are suggested, and the surface structure of the lysozyme molecule immobilized at amino groups is determined based on three-dimensional structure of lysozyme in the Protein Data Bank. (c) 2008 Elsevier B.V. All rights reserved.

The orientation of a lysozyme immobilized with a monoclonal antibody was evaluated based on determination of the uppermost surface structure using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specific peaks of the oriented lysozyme immobilized with monoclonal anti-lysozyme antibody were obtained in comparison with reference samples, non-oriented immobilized lysozyme and immobilized anti-lysozyme antibody. All samples were freeze-dried before TOF-SIMS measurement, and then each sample was measured using TOF-SIMS with a bismuth cluster ion source. TOF-SIMS spectra were analyzed to select peaks specific to the oriented immobilized lysozyme as well as to identify their chemical formula and ensemble of amino acids. The possible chemical formulae of the lysozyme fragments were then investigated with an element matching program and a residue matching program. The results from TOF-SIMS spectra analysis were compared to the amino acid sequence of the lysozyme and its three-dimensional structure registered in the protein data bank. Finally, the fragment-ion-generating regions of the oriented immobilized lysozyme were determined based on the suggested residues and the three-dimensional structure. (c) 2008 Elsevier B.V. All rights reserved.

A variety of aryl iodides were coupled with aromatic and aliphatic terminal alkynes to give the corresponding 1,2-distributed aromatic alkynes in good yields by using only 0.4 mol% of the heterogeneous 10% Pd/C as the catalyst without a ligand, copper salt, or amine in an aqueous medium.

The electrical potential oscillation at and the shape of the water/octanol interface were investigated using hydrophobic fluoroplastic containers. The interfacial potential between a water solution containing 1.5 mM sodium dodecyl sulfate (SDS) and an octanol solution containing 5 mM tetrabutylammonium chloride oscillated with an amplitude of 50-100 mV. The potential oscillation was also observed using a transparent fluoroplastic tube. The water/octanol interface shape was unchanged and no interfacial flow was observed during the oscillation. The interface shape was convex toward the octanol phase for 1.5 mM SDS, meaning that SDS adsorption to the wall was suppressed by the hydrophobic container. Therefore, the octanol system in a hydrophobic container enabled us to elucidate the electrical oscillation without any influence from the wall effect. (c) 2006 Elsevier Inc. All rights reserved.

This study investigated the control of dissolved oxygen concentration using magnetic forces from gradient magnetic fields near a Nd-Fe-B permanent magnet. Maximum values of magnetic flux density and the product of the magnetic flux density and its gradient were 0.63 T and 44 T(2)/m, respectively. The magnet was placed under a Petri dish filled with 15 ml of 10% ammonia water. The Petri dish had a copper sheet in the center. Absorbance of tetraamminecopper(II) complex produced by the reaction in oxygen was measured using a spectrophotometer to observe oxygen concentration. Results showed that the magnetic field quantitatively enhanced tetraamminecopper(II) complex production. Moreover, remarkable enhancement of the copper complex production occurred in the magnetic field at less than 2 mm depth. The calculated magnetic force increase near the magnet surface supports this result. These results show that greater enhancement of the reaction rate occurs when the stronger magnetic force acts on oxygen molecules. (c) 2006 Elsevier B.V. All rights reserved.

An oscillating electrical potential across a liquid membrane is studied as a model of a biological system. The oscillating potential is caused by repeated surfactant adsorption and desorption at the interface. The surfactant desorption process was simulated using both Fick's diffusion equation and the Langmuir-Hinshelwood equation. A water/octanol/water liquid membrane containing sodium dodecyl sulfate (SDS) was used and the effect of NaCl was studied. Calculations agree closely with experimental results, supporting the validity of the model we propose. Adsorption rate constants were obtained by comparing the experimental and calculated results. The addition of NaCl increased adsorption rate constants and decreased desorption rate constants. Calculations suggest that surfactant desorbs mainly into the octanol phase and this desorption is not affected by the addition of NaCl. The disordering of potential oscillations by NaCl addition may be caused by decreased SDS accumulation in the octanol phase close to the interface. A lower adsorption rate of the surfactant from the octanol phase onto the water/octanol interface leads to an oscillating electrical potential across the liquid membrane. (c) 2006 Elsevier B.V. All rights reserved.

Enhancement of the secondary ion intensity in the TOF-SIMS spectra obtained by Au<Sup>+</Sup> and Au<Sub>3</Sub><Sup>+</Sup> bombardment was investigated in comparison with Ga<Sup>+</Sup> excitation using polymer samples with different molecular weight distributions. Since the polymer samples used in this experiment have wide molecular weight distributions, the advantages of a gold cluster primary ion source over a monoatomic ion source could systematically be evaluated. It was found that a Au primary ion source for a TOF-SIMS instrument has advantages in such terms as (1) the mass effect of the monoatomic primary ion, i.e., Au<Sup>+</Sup> vs. Ga<Sup>+</Sup>, (2) the cluster primary ion effect of Au<Sub>3</Sub><Sup>+</Sup> compared with Au<Sup>+</Sup> and Ga<Sup>+</Sup>, and (3)decrease in the degree of fragmentation by usage of a cluster primary ion beam compared with a monoatomic ion beam.

Orientation of immobilized proteins on bio-devices is important to obtain their high performance. Structural change in a particular area of a protein is also very important for the study of the protein performance and the evaluation of the bio-devices. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is able to analyze upper surface of one layer of molecules. Orientation of immobilized proteins can be evaluated based on determination of a partial structure, representing ensemble of amino acids, on the surface part. The model protein, bovine serum albumin (BSA), is immobilized on the substrate, indium-tin oxide (ITO) glass electrode, by covalent bonding. Two types of the oriented samples were prepared by controlling the binding parts of BSA. The results from TOF-SIMS spectra analysis were compared to the amino acid sequence to examine surface parts of the immobilized BSA at different groups. The surface parts of the BSA molecules immobilized on ITO glass plates with different parts of the molecule, amino groups or carboxyl groups, are evaluated by means of TOF-SIMS. The orientation differences were clearly shown in TOF-SIMS spectra of the samples. Furthermore, fragment-ion-generating parts of immobilized-BSA are determined by fragment ions of particular combinations of amino acids in the sequence of BSA. © 2006 The Surface Science Society of Japan (http://www.sssj.org/ejssnt).

We investigated the enhancement of the secondary ion intensity in the TOF-SIMS spectra obtained by Au(+) and Au(3+) bombardment in comparison with Ga(+) excitation using polymer samples with different molecular weight distributions. Since the polymer samples used in this experiment have a wide molecular weight distribution, the advantages of the gold cluster primary ion source over monoatomic ion could accurately be evaluated. It was observed that the degree of fragmentation decreased by the usage of cluster primary ion beam compared with monoatomic ion beam, which was observed as a shift of the intensity distribution in the spectra. It was also found out that the mass effect of Au(+) and Ga(+) as monoatomic primary ion, resulted in about 10-60 times of enhancement for both samples with different molecular distributions. On the other hand, the Au(3)(+) bombardment caused intensity enhancement about 100-2600 compared with Ga(+) bombardment, depending on the mass range of the detected secondary ion species. The cluster primary ion effect of Au(3)(+), compared with Au(+), therefore, was estimated to be about 10-45. (c) 2006 Published by Elsevier B.V.