bluuebunny/crossref_metadata_2025 huggingface dataset:
THE UTILITY OF PROTEOMICS IN ALGAL TAXONOMY: BOSTRYCHIA RADICANS/B. MORITZIANA (RHODOMELACEAE, RHODOPHYTA) AS A MODEL STUDY1
Authors: Kim Gwang Hoon , Shim Jun Bo , Klochkova Tatyana A. , West John A. , Zuccarello Giuseppe C.
Published: November 2008

A comparison of the proteome of eight genetically well‐characterized isolates of the Bostrychia radicans (Mont.) Mont./B. moritziana (Sond. ex Kütz.) J. Agardh species complex was undertaken to establish if genetic relationships among them can be determined using proteome data. Genetic distances were calculated on the basis of common and distinct spots in two‐dimensional gel electrophoresis (2‐DE). Proteomes of the male and female plants of each population were compared to analyze the range of genetic difference within an isolate. Haploid male and female plants of the same species had 3.7%–7.1% sex‐specific proteins. The degree of similarity of the proteome was consistent with previous DNA sequence data and sexual compatibility studies between the isolates. Two sexually compatible isolates from Venezuela showed a pair‐wise distance ranging from 0.14 to 0.21. The isolates from Mexico and Venezuela, which were partially compatible, showed a maximum pair‐wise distance of 0.26. A high level of genetic difference was found among isolates that were sexually incompatible. The isolate from Brazil was reproductively isolated from the Mexico and Venezuela isolates and showed a maximum pair‐wise distance of 0.65 and 0.58, respectively. Comparative proteomics may be helpful for studying genetic distances among algal samples, if intraisolate variation (gene expression) can be minimized or tested.
PHYTOPLANKTON COMMUNITY COMPOSITION AND GENE EXPRESSION OF FUNCTIONAL GENES INVOLVED IN CARBON AND NITROGEN ASSIMILATION1
Authors: Ward B. B.
Published: November 2008

A functional gene microarray was developed and used to investigate phytoplankton community composition and gene expression in the English Channel. Genes encoding the CO2‐fixation enzyme RUBISCO (rbcL) and the nitrate assimilation enzyme nitrate reductase (NR) representing several major groups of phytoplankton were included as oligonucleotide probes on the “phytoarray.” Five major groups of eukaryotic phytoplankton that possess the Type 1D rbcL gene were detected, both in terms of presence (DNA) and activity (rbcL gene expression). Changes in relative signal intensity among the Type 1D rbcL probes indicated a shift from diatom dominance in the spring bloom to dominance by haptophytes and flagellates later in the summer. Because of the limitations of a smaller database, NR probes detected fewer groups, but due to the greater diversity among known NR sequences, NR probes provided higher phylogenetic resolution than did rbcL probes and identified two uncultivated diatom phylotypes as the most abundant (DNA) and active (NR gene expression) in field samples. Unidentified chlorophytes and the diatom Phaeodactylum tricornutum Bohlin were detected at both the DNA and cDNA (gene expression) levels. The reproducibility of the array was evaluated in several ways, and future directions for further improvement of probe development and sensitivity are outlined. The phytoarray provides a relatively high‐resolution, high‐throughput approach to assessing phytoplankton community composition in marine environments.
Association Analyses of Genetic Polymorphisms of GSTM1, GSTT1, NQO1, NAT2, LPL, PRSS1, PSTI, and CFTR With Chronic Alcoholic Pancreatitis in Japan
Authors: Maruyama Katsuya , Harada Shoji , Yokoyama Akira , Mizukami Satoshi , Naruse Satoru , Hirota Masahiko , Nishimori Isao , Otsuki Makoto
Published: November 2008

Background:  Excessive consumption of alcohol is involved in the onset of pancreatitis. However, most of heavy drinkers do not always develop chronic pancreatitis. Various genetic factors appear to be involved in these individual differences in onset of chronic alcoholic pancreatitis. Here we investigated a possible association of alcoholic pancreatitis with polymorphisms of the various genes belong to the phase II detoxification enzymes responsible for metabolism of the oxidative compounds, and the several genes that have relevance to inherited pancreatitis.

Methods:  The subjects consisted of 53 patients with chronic alcoholic pancreatitis, 54 alcoholic patients without pancreatic dysfunction, and 42 healthy individuals. DNA was extracted from the peripheral nucleated blood cells of all subjects and genetic mutations and subtypes were analyzed by the PCR and RFLP methods. We examined the correlation between chronic alcoholic pancreatitis and variants of the phase II detoxification enzymes such as Glutathione S‐transferase M1 (GSTM1), glutathione S‐transferase theta 1 (GSTT1), NADPH‐quinone oxidoreductase 1 (NQO1), and N‐acetyl transferase (NAT2). In addition, genes of lipoprotein lipase (LPL), cationic trypsinogen (PRSS1), pancreatic secretory trypsin inhibitor (PSTI), and cystic fibrosis transmembrane conductance regulator (CFTR) were also analyzed.

Results:  Frequencies of the gene deletion of GSTM1 and GSTT1 in addition to the C‐allele frequency of NQO1 tended to be higher in the alcoholic patients with (AlCP) or without pancreatic dysfunction (Alc) than in the healthy controls although the difference was not significant. The NAT2 gene showed no relation with Alc and AlCP patients. PSTI, LPL, PRSS1, and CFTR genes presented no association with chronic alcoholic pancreatitis.

Conclusions:  All genes analyzed in the present study lacked association with chronic alcoholic pancreatitis. However, the gene deletion of GSTM1 and GSTT1, and the C‐allele of NQO1 cannot be ruled out for association with alcoholism.
Influences of Gender and Age on Relationships Between Alcohol Drinking and Atherosclerotic Risk Factors
Authors: Wakabayashi Ichiro , Araki Yoshihiko
Published: November 2008

Background:  Alcohol drinking affects atherosclerotic progression mainly through blood pressure and lipid metabolism. The purpose of the present study was to clarify whether effects of alcohol drinking on atherosclerotic risk factors differ by gender and age.

Methods:  The database of periodic health check‐ups for local district workers was used. The subjects were divided into 3 groups according to mean ethanol consumption per day (nondrinkers; light drinkers, less than 30 g per day; moderate‐to‐heavy drinkers, 30 g or more per day). The mean levels of each atherosclerosis‐related variable in the 3 groups were compared.

Results:  The mean level of body mass index (BMI) was slightly but significantly lower in drinkers than in nondrinkers in the thirties, forties, and fifties age groups in men and in the twenties, thirties, forties, and fifties age groups in women, while this tendency was not found in the sixties age groups of men and women. In men, mean blood pressure was higher in moderate‐to‐heavy drinkers than in nondrinkers in all age groups and was higher in light drinkers than in nondrinkers only in the age groups after 40 years. Mean blood pressure of women was higher in the moderate‐to‐heavy drinker group than in the nondrinker group and this difference became higher with advance of age. In women, mean blood pressure was not affected by light drinking in any of the age groups except for the fifties age group. In men, serum total cholesterol was higher in drinkers than in nondrinkers in the twenties age group but was lower in drinkers than in nondrinkers at thirties or older. Serum total cholesterol in women was lower in drinkers than in nondrinkers in the age groups from twenties to forties but tended to be higher in drinkers than in nondrinkers in the sixties age group. Serum HDL cholesterol increased with advance of age from thirties to sixties in men, while it decreased with advance of age from twenties to sixties in women. Serum HDL cholesterol was higher in drinkers than in nondrinkers in all age groups of men and women, and atherogenic index, calculated by using serum total cholesterol and HDL cholesterol concentrations, was lower in drinkers than in nondrinkers in all age groups of men and women.

Conclusion:  Both in men and women, blood pressure and HDL cholesterol were strongly affected by alcohol drinking: the elevating effect of alcohol drinking on blood pressure was more prominent in the elderly than in the young, while the elevating effect of alcohol drinking on serum HDL cholesterol was not influenced by age. Relationships of drinking with total cholesterol and BMI vary by age and gender.
The Reasonable Person Negligence Standard and Liability Insurance
Authors: Bajtelsmit Vickie , Thistle Paul D.
Published: November 2008

Abstract

We show that, under the reasonable person negligence rule, heterogeneity of potential injurers can be sufficient to create a demand for liability insurance. Potential injurers with a low probability of accidents or a high cost of exercising care have optimal levels of care that are below the negligence standard. For these groups, it may be less costly to be negligent and purchase insurance than to comply with the negligence standard. We show that the availability of insurance is socially desirable.
Market Risk, Interest Rate Risk, and Interdependencies in Insurer Stock Returns: A System‐GARCH Model
Authors: Carson James M. , Elyasiani Elyas , Mansur Iqbal
Published: November 2008

Abstract

We examine market risk, interest rate risk, and interdependencies in returns and return volatilities across three insurer segments within a System‐GARCH framework. Three main results are obtained: market risk is greatest for accident and health (A&H) insurers, followed by life (Life) and property and casualty (P&C) insurers; interest rate sensitivity is negative and greatest for Life insurers; and interdependencies in returns are significant with the magnitude being strongest between P&C and A&H insurers. The implication is that greatest diversification benefits arise between Life and the other segments of the insurance industry. Market risk and interest rate risk for diversified firms are smaller than those for nondiversified firms for both product and geographic diversification.
The Market Structure–Performance Relationship in the International Insurance Sector
Authors: Pope Nat , Ma Yu‐Luen
Published: November 2008

Abstract

This article tests the applicability of the structure–conduct–performance (SCP) hypothesis in the international nonlife insurance marketplace. We employ a panel data regression methodology that includes 23 nations (developed and developing countries) over the time period of 1996 to 2003. The results reveal that the interaction of market liberalization and market concentration shares a complex relationship with market profitability. Our results show that the expectations associated with the SCP hypothesis are supported when the levels of liberalization are low. However, for markets that are highly liberalized the presence of foreign insurers significantly alters the dynamics of nonlife insurance markets.
Consumption Externality and Equilibrium Underinsurance
Authors: Huang Rachel J. , Tzeng Larry Y.
Published: November 2008

Abstract

Relative consumption has been found to be crucial in many areas, such as asset pricing, the design of taxation, and economic growth. This article extends this line of research to the individual's insurance decision. We first define “keeping up with the Joneses” in the purchase of insurance and find that jealousy does not necessarily give rise to “keeping up with the Joneses.” We also identify several sufficient conditions that cause the optimal coverage in the private market to be less than the social optimum (equilibrium underinsurance). Jealousy is found to be neither a sufficient nor a necessary condition for equilibrium underinsurance. We further show that a social welfare maximizing government could adopt a tax system to correct for the consumption externality and make individuals better off.
Differences in hi‐tech immigrant earnings and wages across Canadian cities
Authors: HALL PETER V. , KHAN AMIR J.
Published: November 2008

This paper examines the relative earnings and wages of immigrants working in the hi‐tech sector in Canada's cities. Between 1990 and 2000, a sizeable earnings advantage of immigrants over nonimmigrants employed in the hi‐tech sector evaporated, and this change was most noticeable in the largest cities. We use population census microdata to examine the geographical dimensions of this shift. After controlling for individual characteristics, we show that immigrants in the largest and tech‐intensive cities earn significantly less relative to nonimmigrants than those in midsized and smaller cities. We also present results comparing the hi‐tech immigrant wage and earnings gap for the five largest Canadian cities. The findings are consistent with the notion that geographic differences are an important component of the overall earnings gap between immigrants and nonimmigrants.
Public participation geographic information systems (PPGIS): challenges of implementation in Churchill, Manitoba
Authors: STEWART EMMA J. , JACOBSON DAN , DRAPER DIANNE
Published: November 2008

Public participation geographic information systems (PPGIS) increasingly are utilized in geographic research, yet researchers rarely are provided with guidance on how to implement PPGIS in an appropriate and effective manner. This article reports on the process of research that explores responses to current and future local tourism development offered by a sample of residents using a modified PPGIS approach called ‘community action geographic information system’ (CAGIS). The conceptual development of CAGIS is reported and the challenges encountered during its implementation in Churchill, Manitoba during 2005–2007 are reviewed. It is suggested that researchers wishing to conduct similar research should undertake thorough preliminary fieldwork to assess the likelihood of finding agreement on a common problem; acquiring adequate resources; establishing collective responsibility for the project's outcome; attaining stakeholder support; developing trust and meaningful relationships; and incorporating indigenous knowledge appropriately. Feedback of results to community members also should be an integral part of the research process. A number of feedback mechanisms are reported, including an interactive weblog, which helped facilitate communication between heterogeneous groups in Churchill. Although ambitions for a truly participatory GIS approach to this project have been set aside, it is held that PPGIS can yield positive outcomes for communities and academia. Sharing this research experience will be useful to others who venture into PPGIS research, especially in northern communities.
NeuralEnsembles: a neural network based ensemble forecasting program for habitat and bioclimatic suitability analysis
Authors: O'Hanley Jesse R.
Published: November 2008

NeuralEnsembles is an integrated modeling and assessment tool for predicting areas of species habitat/bioclimatic suitability based on presence/absence data. This free, Windows based program, which comes with a friendly graphical user interface, generates predictions using ensembles of artificial neural networks. Models can quickly and easily be produced for multiple species and subsequently be extrapolated either to new regions or under different future climate scenarios. An array of options is provided for optimizing the construction and training of ensemble models. Main outputs of the program include text files of suitability predictions, maps and various statistical measures of model performance and accuracy.
Bioenergetic requirements of a Tat‐dependent substrate in the halophilic archaeon Haloarcula hispanica
Authors: Kwan Daniel C. , Thomas Judith R. , Bolhuis Albert
Published: November 2008

Twin‐arginine translocase (Tat) is involved in the translocation of fully folded proteins in a process that is driven by the proton motive force. In most prokaryotes, the Tat system transports only a small proportion of secretory proteins, and Tat substrates are often cofactor‐containing proteins that require folding before translocation. A notable exception is found in halophilic archaea (haloarchaea), which are predicted to secrete the majority of their proteins through the Tat pathway. In this study, we have analysed the translocation of a secretory protein (AmyH) from the haloarchaeon Haloarcula hispanica. Using both in vivo and in vitro translocation assays, we demonstrate that AmyH transport is Tat‐dependent, and, surprisingly, that its secretion does not depend on the proton motive force but requires the sodium motive force instead.
Effect of magnesium ions on the activity of the cytosolic NADH/cytochrome c electron transport system
Authors: La Piana Gianluigi , Gorgoglione Vincenza , Laraspata Daniela , Marzulli Domenico , Lofrumento Nicola E.
Published: November 2008

Cytochrome c (cyto‐c), added to isolated mitochondria, activates the oxidation of extramitochondrial NADH and the generation of a membrane potential, both linked to the activity of the cytosolic NADH/cyto‐c electron transport pathway. The data presented in this article show that the protective effect of magnesium ions on the permeability of the mitochondrial outer membrane, supported by previously published data, correlates with the finding that, in hypotonic but not isotonic medium, magnesium promotes a differential effect on both the additional release of endogenous cyto‐c and on the increased rate of NADH oxidation, depending on whether it is added before or after the mitochondria. At the same time, magnesium prevents or almost completely removes the binding of exogenously added cyto‐c. We suggest that, in physiological low‐amplitude swelling, magnesium ions may have the function, together with other factors, of modulating the amount of cyto‐c molecules transferred from the mitochondrial intermembrane space into the cytosol, required for the correct execution of the apoptotic programme and/or the activation of the NADH/cyto‐c electron transport pathway.
Calcium‐independent phospholipase A2‐mediated formation of 1,2‐diarachidonoyl‐glycerophosphoinositol in monocytes
Authors: Balgoma David , Montero Olimpio , Balboa María A. , Balsinde Jesús
Published: November 2008

Phagocytic cells exposed to exogenous arachidonic acid (AA) incorporate large quantities of this fatty acid into choline and ethanolamine glycerophospholipids, and into phosphatidylinositol (PtdIns). Utilizing liquid chromatography coupled to MS, we have characterized the incorporation of exogenous deuterated AA ([2H]AA) into specific PtdIns molecular species in human monocyte cells. A PtdIns species containing two exogenous [2H]AA molecules (1‐[2H]AA‐2‐[2H]AA‐glycero‐3‐phosphoinositol) was readily detected when human U937 monocyte‐like cells and peripheral blood monocytes were exposed to [2H]AA concentrations as low as 160 nm to 1 μm. Bromoenol lactone, an inhibitor of Ca2+‐independent phospholipase A2 (iPLA2), diminished lyso‐PtdIns levels, and almost completely inhibited the appearance of 1‐[2H]AA‐2‐[2H]AA‐glycero‐3‐phosphoinositol, suggesting the involvement of deacylation reactions in the synthesis of this phospholipid. De novo synthesis did not appear to be involved, as no other diarachidonoyl phospholipid or neutral lipid was detected under these conditions. Measurement of the metabolic fate of 1‐[2H]AA‐2‐[2H]AA‐glycero‐3‐phosphoinositol after pulse‐labeling of the cells with [2H]AA showed a time‐dependent, exponential decrease in the level of this phospholipid. These results identify 1‐[2H]AA‐2‐[2H]AA‐glycero‐3‐phosphoinositol as a novel, short‐lived species for the initial incorporation of AA into the PtdIns class of cellular phospholipids in human monocytes.
Degradation of Refractory Bricks Used as Thermal Insulation in Rotary Kilns for Iron Ore Pellet Production
Authors: Stjernberg Jesper , Antti Marta‐Lena , Nordin Lars‐Olof , Odén Magnus
Published: November 2008

Degradation of bricks in an iron ore pellet producing kiln has been investigated. Lab‐scale tests of brick/slag interaction performed under different temperatures, atmospheres, and alkali additions show that addition of alkali dissolves the mullite in the brick and leads to formation of the phase nepheline (Na2O·Al2O3·2SiO2). At a high temperature, the grain boundary where nepheline is formed disintegrates due to volume expansion. At increased temperature, the nepheline transforms to an amorphous phase. Thus, a wear mechanism is proposed in the kiln using these bricks that involves these chemical reactions in combination with erosion by the continuously flowing slag.
Role of Liquid Phase in Achieving a Fine Microstructure and Diffusive Phase Transition of MgO‐Doped BaTiO3
Authors: Bae Shin‐Tae , Yim Dong Kyun , Hong Kug Sun , Park Jin‐Soo , Shin Hyunho , Jung Hyun Suk
Published: November 2008

Two types of glass compositions, with MgO and CaO modifiers, respectively, were used to promote l`iquid‐phase sintering of 2 mol% MgO–BaTiO3at 1280°C in reducing atmosphere (pO2=10−9 atm). By combining the observations of the grain size of about 1 μm for both specimens and the diffusive phase transition only when MgO modifier was used, it has been interpreted that an appropriate solubility of BaTiO3is necessary to yield the fine and composite microstructures via a dissolution–reprecipitation process. Further, a reasonable dopant provision to BaTiO3has been shown to be required to achieve the diffusive phase transitions.
Ablation Resistance of Different Coating Structures for C/ZrB2–SiC Composites Under Oxyacetylene Torch Flame
Authors: Li Houbu , Zhang Litong , Cheng Laifei , Wang Yiguang
Published: November 2008

C/ZrB2–SiC composites were fabricated by polymer infiltration and pyrolysis combined with slurry impregnation method. Three kinds of coating structures for these composites were applied in order to improve their ablation resistance: pure silicon carbide coatings, ZrB2–SiC mixture coatings, and ZrC–SiC alternating multilayer coatings. The ablation experiments were carried out on an oxyacetylene torch flame with a temperature of about 3000°C. The ZrC–SiC alternating multilayer showed the best ablation resistance. The linear erosion rate for ZrC–SiC alternating multilayer coatings is half of that for ZrB2–SiC mixture and pure SiC coatings. A model was put forward to account for such a result.
Feasibility Study of a Thick‐Film PZT Resonant Pressure Sensor Made on a PreFired 3D LTCC Structure
Authors: Zarnik Marina Santo , Belavič Darko , Maček Srečko , Holc Janez
Published: November 2008

This paper discusses the feasibility of a piezoelectric resonant pressure sensor made of lead–zirconate–titanate (PZT) thick films on a preprocessed 3D low‐temperature co‐fired ceramic structure with a deformable diaphragm. Numerical and experimental analyses were carried out. Two different thick‐film PZT compositions were characterized. Using experimentally evaluated material properties, a finite‐element analysis showed the trends and facilitated the decisions in the design phase of the sensor.
Establishing an innovative model of nutrition and dietetic care for a mental health service through collaboration with non‐nutrition healthcare workers
Authors: WILKINSON Shelley , HIMSTEDT Kellie
Published: November 2008

Aim:  To describe the process of the development of the Web‐based resources to extend nutrition care to mental health patients through existing non‐nutrition mental healthcare professionals (case‐managers).

Methods:  A formative approach was used to identify nutrition‐related issues faced by both patients and staff through a synthesis of literature review, professional experience and clinical observations. Decision‐making tools to assist case‐managers in selecting resources were developed to guide case‐managers’ choice of effective evidence‐based health education materials on the hospital intranet. Practical training was provided for case‐managers during their orientation to the new website and the tools and resources it housed.

Results:  A Web‐based nutrition site was created on the Royal Brisbane and Women's Hospital intranet. The website consisted of a Nutrition Referral Action Plan (a patient support triaging flowchart), a Nutrition Support Action Plan (action‐based nutrition support tool to guide resource selection) and thirteen action‐based nutrition education resources.

Conclusion:  By maximising established patient contact through existing health professionals, a Web‐based approach to nutrition service delivery was an innovative method for delivering patient information. This collaborative action‐based strategy has the potential to raise the nutrition profile in mental health and extend nutrition services to at‐risk patients not previously receiving nutrition care.
Comparison of nutrient intake between different dietary assessment methods in elderly male volunteers
Authors: JOHANSSON Gunnar
Published: November 2008

Aim:  The objective of the study was to compare nutritional intake results obtained from the 4 × 4‐day weighed records with those obtained from a food frequency questionnaire, repeated 24‐hour recalls, a seven‐day food record and a seven‐day checklist in elderly men.

Methods:  Seventy‐five healthy men aged 55–88 years and living at home in Cambridge, UK, took part in the study. Energy and nutrients had means and standard deviations calculated. Misreporting was based on an evaluation of food intake level, calculated as reported energy intake divided by predicted basal metabolic rate. This was in relation to a plausible physical activity level, calculated as the ratio of energy expenditure divided by predicted basal metabolic rate. Statistical significance was assessed via one‐way anova.

Results:  The nutrient density was higher for protein and potassium for the group with low food intake level values in all dietary assessment methods. For some methods, this was also true for calcium, carotene, iron and vitamin C. All methods yielded similar results.

Conclusions:  The present study indicates that selective underreporting exists. Surprisingly, the simplest method, the simplified 24‐hour recall, performed as well as more complicated methods.
Glycation Methods for Bombesin Analogs Containing the (NαHis)Ac chelator for 99mTc(CO)3 Radiolabeling
Authors: Brans Luc , Maes Veronique , García‐Garayoa Elisa , Schweinsberg Christian , Daepp Simone , Bläuenstein Peter , August Schubiger P. , Schibli Roger , Tourwé Dirk A.
Published: November 2008

The overexpression of peptide receptors in a variety of human carcinomas has generated considerable interest in peptide‐based radiopharmaceuticals for peptide receptor imaging and peptide receptor radiotherapy. The gastrin‐releasing peptide receptor is overexpressed in human prostate‐, breast‐, colon‐ and small cell lung carcinoma cells. We have developed metabolically stable 99mTc‐radiolabeled bombesin ([Cha13, Nle14]BBS(7–14)) analogs, which bind with high affinity to the gastrin‐releasing peptide receptors. However, because of their lipophilicity, they showed unfavorable biodistribution with high hepatic accumulation and hepatobiliary excretion. We now report a study of different glycation methods for [Cha13, Nle14]BBS(7–14) analogs to improve their biodistribution profile. Whereas the glycation using the Maillard reaction was problematic, resulting in low yields, selective introduction of the glycomimetic shikimic acid to the side chain of a Lys residue was possible. A chemoselective ligation of α‐d‐glucose to an amino‐oxyacetylated [Cha13, Nle14]BBS(7–14) analog could be achieved, but was complicated by the co‐elution of starting peptide and glycopeptide. The best procedure consisted of the [1,3]‐cycloaddition of N3‐β‐d‐glucose to a propargylglycine‐containing [Cha13, Nle14]BBS(7–14) analog, using a catalytic amount of Cu(I)I. All glycated [Cha13, Nle14]BBS(7–14) analogs showed high affinity for the gastrin‐releasing peptide receptor and rapid accumulation into PC‐3 tumor cells.
“Brown Ore” from the Fukasawa Kuroko Deposits, Northeast Japan: Its Characteristics and Formation Process
Authors: ISHIZUKA Osamu , IMAI Akira
Published: November 2008

Abstract: Brown–colored sulfide ore (brown ore) occurs in the easternmost part of the Tsunokakezawa No. 1 orebody of the Fukasawa kuroko‐type deposits, northern Honshu, Japan. As this type of ores also occur in the marginal or uppermost part of several other kuroko deposits in Japan, the formation of brown ore appears to be repeated in the process of kuroko formation. The brown ore is characterized by its higher Ag concentration (up to around 2000 g/t) than ordinary black ore (Zn–Pb ore) of volcanogenic massive sulfide deposits. The brown ore from the Fukasawa deposits can be divided into following three ore types based on its texture and mineral composition: pyritic brown ore, principal brown ore and “diseased” brown ore. Primary precipitation textures such as framboidal– and colloform‐textures and compositional zoning within sulfide grains are significant in the brown ores. This seems to be due to lack of overprinting high temperature mineralization resulting in preservation of primary features. The Ag‐Au mineralization is widely observed within the brown ores. Silver and gold are especially concentrated in the barite veinlets in the principal brown ore, which are supposed to be fillings of conduit of hydrothermal solution precipitated in the latest stage of hydrothermal activity. This mineralization seems to occur at waning stage of brown ore formation by ore solution at a lower temperature (around 250°C) than that of main part of brown ore (around 270°C). Relatively low fluid temperature and contribution of oxic ambient seawater may be responsible for the development of the Ag‐Au mineralization in the brown ore. The occurrence of framboidal‐rich pyritic brown ore having negative δ34S values (less than –10%) and filamentous texture of sphalerite, seeming remnant of bacteria, indicate the presence of intensive microbial activity in the hydrothermal area for brown ore formation.

Formation environment of each ore type of the brown ore is supposed to be as follows: Pyritic brown ore is likely to have formed on the sea‐floor around redox boundary at temperature (around 240°C) lower than ordinary black ore. Principal brown ore seems to have been formed beneath the shell of the pyritic brown ore at temperature around 270°C. Footwall of the brown ore is disseminated tuff breccia corresponding to feeder zone of hydrothermal fluid. Overprinting chalcopyrite mineralization is not observed in the brown ore except in limited part of “diseased” ore, which occurs just above the disseminated tuff breccia.

Based on the features distinct from the ordinary black ore, the brown ore can be regarded as a product in the marginal part of submarine hydrothermal system, where temperature and flow rate of hydrothermal solution was relatively low and microbial activity was intensive. The brown ore seems to well preserve its primary features after its deposition and might show the initial feature of some part of the ordinary stratiform black ore.
Geology, Mineralogy, and Formation Environment of the Disseminated Gold‐Silver Telluride Bulawan Deposit, Negros Occidental, Philippines
Authors: MAGLAMBAYAN Victor B. , ISHIYAMA Daizo , MIZUTA Toshio , IMAI Akira , ISHIKAWA Yohei
Published: November 2008

Abstract: The Bulawan deposit is located in the porphyry copper belt of southwest Negros island, Philippines. Propylitic, K–feldspar, sericitic, and carbonate alteration types can be distinguished in the deposit. Propylite alteration occurs mainly in Cretaceous‐Eocene andesitic lavas and agglomerates while K–feldspar, sericite and carbonate alteration types occur mostly in the Middle Miocene dacite porphyry breccia pipes and stocks which were intruded into the andesites. K‐feldspar zones occur in the inner parts of the sericitized zone. Sericite alteration overprinted the propylitized and K‐feldspar alteration zones, at lower temperature than epidote and chlorite in the propylitized zone. Carbonate alteration is associated with the mineralization in the center of the breccia pipes and along faults.

Mineralization consists of gold‐silver telluride ores that are hosted by the carbonate– and sericite‐altered dacite porphyry breccia pipes. The Bulawan ores occur mainly as disseminations, but unlike many epithermal gold deposits, lack classical epithermal colloform and crustiform quartz veins. The ore minerals are sphalerite, galena, chalcopyrite, pyrite and tetrahedite‐tennantite with minor amounts of electrum, calaverite, petzite, sylvanite, hessite, tellurobismuthite, coloradoite, altaite, and rucklidgeite. Electrum and telluride minerals are associated mostly with calcite and dolomite‐ankerite minerals.

Fluid inclusions in quartz and calcite in clasts of propylitized andesite in the breccia pipes homogenize from about 300° to 400°C while fluid inclusions in quartz, calcite and sphalerite within the dacite porphyry breccia pipes homogenize between 300° to 310°C. The ores were formed around 300°C from hydrothermal solutions with salinity of about 6. 6 wt % NaCl equivalent. The presence of sylvanite and calaverite as intergrowths with each other, and the Ag content of calaverite are consistent with the above temperature estimate. Based on paragenesis, the Bulawan deposit formed in a pyrite‐stable environment, with pH between 3. 4 and 5. 5, fO2 between 10‐32 to 10‐30 atm, fS2 between 10‐9.8 to 10‐7.8 atm, fTe2 between 10‐8.9 to 10‐6.5 atm, and total sulfur content about 10‐2.8 molal. The dominant reduced sulfur species in the ore solutions may have been H2S(aq), and the likely aqueous tellurium species were H2Te(aq) and H2TeO3(aq). The ore minerals in the Bulawan deposit were probably formed by mixing of slightly saline and low salinity fluids.
Two Se‐bearing Ag–Bi Sulphosalts, Benjaminite and Matildite from the Ikuno Deposits, Hyogo Prefecture, Japan –Au–Ag Mineralization in Polymetallic Zone
Authors: SHIMIZU Masaaki , KATO Akira , MATSUYAMA Fumihiko
Published: November 2008

Abstract: Se‐bearing benjaminite and matildite are described from the polymetallic zone of the Ikuno deposits, Japan. The former is the first occurrence in Japan, and is from two separate veins, the Nanten and Daimaru, while the locality of the latter could not be specified. The empirical formulae of two benjaminites based on 22 atoms are (Ag2. 74Cu0. 24)Σ2. 98(Bi7. 00Sb0. 01)Σ7. 01(S10. 89Se1. 12)Σ12. 01 (Nanten) and (Ag2. 90Cu0. 10)Σ3. 00(Bi6. 74Pb0. 18Sb0. 07)Σ6. 99(S11. 68Se0.33)Σ12. 01 (Daimaru), leading to the validation of the formula Ag3Bi7S12 as the ideal one for benjaminite, and that of matildite based on 4 atoms is Ag1. 00Bi1. 00(S1. 78Se0. 22)Σ2. 00. These designate the substitution of Se for S in all of them, where Se is preferentially incorporated into these Ag‐Bi sulphosalts. The unit‐cell parameters of them and matildite are: a 13. 272, b 4. 037, c 20. 185 Å, and β 103. 16° (Daimaru), a 13. 270, b 4. 040, c 20. 273 Å, and β103. 17° (Nanten); and a 4. 0670, c 18. 996 Å, respectively. The products of Au‐Ag mineralization in the Ikuno polymetallic vein‐type deposits also occur as such Ag‐Bi sulfosalts as benjaminite and matildite, in addition to pavonite, “treasurite derivative” and “electrum” with cassiterite in the polymetallic zone, and also do as “electrum”, acanthite, and pyrargyrite‐proustite in the Au‐Ag zone. The significant quantity of the Ag‐Bi sulfosalts does not violate the zoning occupying the outermost part of the zonal distribution of ores in the deposits.
Hydrogen Isotope Study of Fluid Inclusions in Vein Quartz of the Hishikari Gold Deposits, Japan
Authors: IMAI Akira , SHIMAZAKI Hidehiko , NISHIZAWA Tomoko
Published: November 2008

Abstract: The origin of mineralizing fluids responsible for the Hishikari vein‐type epithermal Au deposits was studied on the basis of the hydrogen isotopic ratio (δD) of the inclusion fluid from vein quartz and adularia. The origin of hydrothermal fluids was estimated by combination of the present δ values and the oxygen isotopic ratios (δ18O) previously reported by Shikazono and Nagayama (1993).

The water in the fluid inclusions was extracted by means of decrepitation of quartz at 500°C. Hydrogen was obtained by reduction of the collected water with Zn shot at 450°C. The δD values were determined by mass spectrometer.

The δD values of inclusion fluid obtained from quartz range from –61 to –114%. These are significantly lower than the δD value of the thermal water presently venting from the Hishikari deposits and that of local meteoric water.

Hydrogen isotopic fractionation between water and amorphous silica, which might have initially precipitated from the hydrothermal fluids at least partly, is not a probable cause of this isotopic depletion, while some water might have been released from the initial hydrous amorphous silica during recrystallization to quartz observed presently. Thus, a part of ore fluids for the Hishikari deposits is supposed to have been originated from the water having anomalous δD values of lower than –100%.

Such D depletion cannot be caused by simple oxygen‐shift of meteoric water or by contribution of magmatic volatiles. The δD values of water released from the shale samples of the Shimanto–Supergroup, a major host to the Hishikari veins range from –132 to –148%. Therefore, the anomalous δD values of inclusion fluids from some vein quartz and adularia suggest that the water released from hydrous minerals of the sedimentary basement rocks by dehydration or the groundwater isotopically exchanged with sedimentary rocks at elevated temperatures during circulation, partly contributed to the hydrothermal fluids responsible for the Hishikari deposits.
Geochemical Evolution of Hydrothermal Fluids at the Daejang Cu–Zn–Pb Vein Deposit, Korea
Authors: CHOI Sang Hoon
Published: November 2008

Abstract: The Daejang mine is located within the Cretaceous Gyeongsang basin. Mineral paragenesis can be divided into four stages (stages I, II, III and IV) by major tectonic fracturing. Stages I, III and IV are economically barren. Stage II, at which the precipitation of major ore minerals occurred, is further divided into three substages with paragenetic time based on minor fractures and discernible mineral assemblages: substage IIa, marked by deposition of quartz and Fe–sulfides; substage IIb, by introduction of base‐metal sulfides within carbonates and some quartz; substage IIc, by quartz and carbonates with various sulfosalts.

Fluid inclusion data indicate a complex geochemical evolution of hydrothermal fluids. Both CO2–rich and H2O–rich fluids were trapped in fluid inclusions at stage I and substage IIa. It is suggested that a compositionally heterogeneous fluid was formed by fluid boiling and CO2 immiscibility at temperatures of about 400° to 300°C. Composite lodes of base‐metal sul–fides, carbonates and quartz at substage IIb were deposited in open spaces created by fracturing. The fracturing event prompted rapid decreases in pressure and temperature of residual fluids and resulted in retrograde fluid boiling at about 200 bars and 300°–250°C during substage IIb. The progressive loss of CO2 by CO2 effervescence and retrograde boiling from substage IIa and IIb fluids resulted in pH increase and related increase in carbonate activity, causing deposition of abundant carbonates. The change in pH also caused the decrease of stability of hydrogen sulfide with Cu, Zn and Pb chloride complexes (as main transporting agents at Daejang) and resulted in the pricipitation of base‐metal minerals. Deposition of Ag– and Sb‐bearing sul–fides and sulfosalts of substage IIc occurred at temperatures of about 250° to 150°C from a dominantly aqueous fluid with low salinity (down to 3. 0 equiv. wt % NaCl). At this substage, aqueous fluid formed by mixing with cooler and less saline meteoric groundwater. There is a systematic decrease in caculated δ18Owater values with the mineralization stage (and decreasing temperature) in the Daejang hydrothermal system, from values of about 11% for stage I, through about 4% for stages II and III, to about –3 per mil for stage IV. The result of stable isotope and fluid inclusion studies are interpreted to indicate progressive less evolved and/or unexchanged meteoric water influx of an early hydrothermal system formed by highly evolved meteoric waters.
Granitoid Series and Mineralization in the Circum‐Pacific Phanerozoic Granitic Belts
Authors: ISHIHARA Shunso
Published: November 2008

Abstract: Throughout the Phanerozoic Era, magnetite‐series and ilmenite‐series granitoids are heterogeneously distributed on both sides of the Pacific Ocean. Ilmenite‐series granitoids are dominant in the western Pacific rim, while magnetite‐series granitoids prediminate in the eastern Pacific orogenic belt. Regional distribution patterns of the two series of paired belt are also recognized differently, implying different tectonic and geochemical settings on both sides of the Pacific Ocean. The differences reflect on the predominance of Sn‐W deposits in the western Pacific but sulfide‐forming mineral commodities in the eastern Pacific rims. To determine redox state of granitoids is the first step in mineral exploration of granitoid affinity.
Temporal, Spatial and Geochemical Discriminations of Granitoids in South Korea
Authors: JWA Yong–Joo
Published: November 2008

Abstract:Five groups of the Phanerozoic granitoids in South Korea can be deduced from their temporal and spatial distributions: (1) Jurassic granitoids in the Gyeonggi massif, (2) Permo‐Jurassic granitoids in the Ogcheon belt, (3) Permo‐Jurassic granitoids in the Yeongnam massif, (4) Cretaceous granitoids in the Ogcheon belt, and (5) Cretaceous granitoids in the Gyeongsang basin. Though the granitoids of each group generally show calc‐alkaline and orogenic natures, the petrological, geochemical and genetical features are different with each other.

The Permo‐Jurassic granitoids in the Ogcheon belt have lower contents of Al2O3, Fe2O3, CaO, P2O5, but higher of FeO, FeOT, MgO, K2O than those in the Yeongnam massif. From higher feature of K2O, Na2O+K2O and K2O/Na2O, the Ogcheon belt seems to have been located at closer continent side relative to the Yeongnam massif during Permo‐Jurassic time. From lower values of Fe2O3/FeO and magnetic susceptibility the granitoids of the Ogcheon belt had been solidified under more reducing environment than those of the Yeongnam massif. The Cretaceous granitoids in the Ogcheon belt have lower contents of TiO2, Fe2O3, FeO, FeOT, CaO and P2O5, but higher of MgO, K2O, Na2O+K2O and K2O/Na2O than those in the Gyeongsang basin. This feature indicates that the Ogcheon belt would correspond to the continental environment of magma genesis during Cretaceous time. Higher values of Fe2O3/FeO and magnetic susceptibility in the Cretaceous granitoids in the Gyeongsang basin suggest that the granitoids had been solidified under highly oxidizing environment. From the particular chemical features of K2O, Na2O+K2O and K2O/Na2O, the Permo‐Jurassic granitoids in the Ogcheon belt, the Yeongnam massif as well as the Cretaceous ones in the Gyeongsang basin can be categorized to the continental margin type granite. The Jurassic granitoids in the Gyeonggi massif are possibly of collision type, and the Cretaceous granitoids in the Ogcheon belt of post–orogenic, intra–conti–nent type. The Jurassic granitoids in the Gyeonggi massif had been possibly generated by crustal melting during the collision of Gyeonggi massif to the northern Pyeongnam basin block. The Cretaceous granitoids in the Ogcheon belt had been emplaced at the hinterland of the continental margin during post‐orogenic stage of the Honam Shear Zone.

The Cretaceous granitoids in the Gyeongsang basin are often compared with Japanese Cretaceous˜Paleogene granitoids in their geochemical and genetical natures. For the granitoid composition, the granitoids in the Gyeongsang basin are higher in Fe2O3, Fe2O3/FeO, Na2O, K2O, Na2O+K2O and K2O/Na2O, but lower in Al2O3, FeO, MnO, CaO and P2O5than the Japanese granitoids. The contents of TiO2, FeOT and MgO are similar in both granitoids. This geochemical contrast would imply that the Cretaceous granitoid magmas in the Gyeongsang basin had been originated at closer place to the continent side under more tensional field, and solidified under more oxidizing environment than the coeval Japanese granitoid magmas.
Ore Mineralogy and Mineral Chemistry of the Ashanti Gold Deposit at Obuasi, Ghana
Authors: OSAE Shiloh , KASE Katsuo , YAMAMOTO Masahiro
Published: November 2008

Abstract: The gold deposit at Ashanti occurs in the Proterozoic Birimian formation of Ghana. Two main ore types mined from the deposit are gold‐bearing quartz veins, and gold‐sulfide disseminations in metasediments and metavolcanics. The main sulfide minerals in the gold‐sulfide disseminated ores are arsenopyrite, pyrite and pyrrhotite, and to a very minor extent, sphalerite and tetrahedrite. Carbonate alteration and sericitization are prominent in the metavolcanics and the metasediments, respectively. In the quartz veins, pyrite and arsenopyrite commonly occur in small amounts, but gold mostly occurs in contact with tetrahedrite, chalcopyrite, galena, aurostibite, and sphalerite. Pyrrhotite is absent in the quartz veins.

Microprobe studies indicate that As content of homogeneous arsenopyrite grains ranges from 27. 0 to 31. 7 atm%, and gives mineralization temperatures from 170 to 430°C, although mostly from 300 to 400°C. Chlorite geothermometry using temperature dependence of substitution of Al for Si in the tetrahedral site gives formation temeratures of 330 to 400°C, comparable to the arsenopyrite temperatures. Applying sphalerite–pyrite–pyrrhotite geobarometry to sphalerite with FeS contents from 13. 6 to 12. 5 mol%, the pressure was estimated to be in a range from 5. 9 to 7. 0 kb at the stage of elevated temperatures.

Mineralogical observations, especially absence of pyrrhotite in the quartz veins, together with microprobe data for gold and associated minerals suggest that the fluids having ascended through fissures in the Ashanti deposit were reduced by the reaction with carbonaceous materials in the metasediments during the declining stage of the regional metamorphism.
Microthermometric Evidence for the Formation of Ca‐rich Hypersaline Brine and CO2–rich Fluid in the Mori Geothermal Reservoir, Japan
Authors: MURAMATSU Yoichi , KOMATSU Ryo
Published: November 2008

Abstract: Fluid inclusions in hydrothermal quartz and anhydrite samples from the Mori geothermal field, southwest Hokkaido, have been studied microthermometrically using heating/freezing stages. Based on homogenization temperatures of fluid inclusions, salinities after correction of effect of freezing‐point depression of CO2 on ice melting temperatures of fluid inclusions, and previous geochemical data by Yoshida (1991), we discuss the geneses of various types of inclusion fluids in the Mori geothermal reservoir.