bluuebunny/crossref_metadata_2025 huggingface dataset:
The Microbiotic Highway to Health—New Perspective on Food Structure, Gut Microbiota, and Host Inflammation
Authors: Hansen Nina Wærling , Sams Anette
Published: October 2018

This review provides evidence that not only the content of nutrients but indeed the structural organization of nutrients is a major determinant of human health. The gut microbiota provides nutrients for the host by digesting food structures otherwise indigestible by human enzymes, thereby simultaneously harvesting energy and delivering nutrients and metabolites for the nutritional and biological benefit of the host. Microbiota-derived nutrients, metabolites, and antigens promote the development and function of the host immune system both directly by activating cells of the adaptive and innate immune system and indirectly by sustaining release of monosaccharides, stimulating intestinal receptors and secreting gut hormones. Multiple indirect microbiota-dependent biological responses contribute to glucose homeostasis, which prevents hyperglycemia-induced inflammatory conditions. The composition and function of the gut microbiota vary between individuals and whereas dietary habits influence the gut microbiota, the gut microbiota influences both the nutritional and biological homeostasis of the host. A healthy gut microbiota requires the presence of beneficial microbiotic species as well as vital food structures to ensure appropriate feeding of the microbiota. This review focuses on the impact of plant-based food structures, the “fiber-encapsulated nutrient formulation”, and on the direct and indirect mechanisms by which the gut microbiota participate in host immune function.
Associations of Lifestyle Behaviour and Healthy Ageing in Five Latin American and the Caribbean Countries—A 10/66 Population-Based Cohort Study
Authors: Daskalopoulou Christina , Koukounari Artemis , Ayuso-Mateos José Luis , Prince Martin , Prina A. Matthew
Published: October 2018

Latin American and the Caribbean countries exhibit high life expectancy and projections show that they will experience the fastest growth of older people in the following years. As people live longer, it is important to maximise the opportunity to age healthily. We aimed to examine the associations of lifestyle behaviours with healthy ageing in Cuba, Dominican Republic, Peru, Mexico and Puerto Rico, part of the 10/66 study. Residents 65 years old and over (n = 10,900) were interviewed between 2003 and 2010. In the baseline survey, we measured four healthy behaviours: Physical activity, non-smoking, moderate drinking and fruits or vegetables consumption. Healthy ageing was conceptualised within the functional ability framework over a median of 4 years follow-up. Logistic models were calculated per country and then pooled together with fixed-effects meta-analysis. People engaging in physical activity and consuming fruits or vegetables had increased odds of healthy ageing in the follow-up (OR: 2.59, 95% CI: 2.20–3.03; OR: 1.24, 95% CI: 1.06–1.44, respectively). Compared with participants engaging in none or one healthy behaviour, the ORs of participants engaging in two, three or four healthy behaviours increased in a linear way (OR: 1.60, 95% CI: 1.40–1.84; OR: 2.29, 95% CI: 1.94–2.69; OR: 2.46, 95% CI: 1.54–3.92, respectively). Our findings highlight the importance of awareness of a healthy lifestyle behaviour among older people.
Polarization Properties and Polarization Depth Profiles of (Cd:Zn)S/P(VDF-TrFE) Composite Films in Dependence of Optical Excitation
Authors: Engel Sebastian , Smykalla David , Ploss Bernd , Gräf Stephan , Müller Frank A.
Published: October 2018

The influence of optical excitation intensity on the electrical, ferroelectric and pyroelectric properties of ferroelectric-semiconductor-composites was investigated. For this purpose, composite thin films consisting of poly(vinylidene fluoride-co-trifluoroethylene) and 10 vol % (Cd:Zn)S particles with a thickness of 34 µm were fabricated. The samples were used to measure the absolute pyrocoefficient and to determine the relative pyroelectric depth profile using Laser Intensity Modulated Method. It was shown that a polarization of the samples without an optical excitation at the utilized relatively small peak-to-peak voltages could not be verified by the Sawyer–Tower circuit and the measurement setup of the pyroelectric coefficient, respectively. Both remanent polarization and pyroelectric coefficients increased with increasing optical excitation intensity during poling as well as increasing peak-to-peak voltage. The pyrocoefficient shows a temporal decay in the first hours after poling. The specific heat and thermal conductivity or the thermal diffusivity are required for the calibration of the pyroelectric depth profile. Rule of mixture and photo-acoustic investigations proved that the thermal properties of the utilized composites do not differ significantly from those of the pristine polymer. Based on the pyroelectric depth profile which is proportional to the polarization profile, the existing “three phase model” has been extended to generate a replacement circuit diagram, explaining the local polarization due to the optical excitation dependency for both local resistivity and local field strength.
Influence of Processing Parameters on Tensile Properties of SLS Polymer Product
Authors: Pilipović Ana , Brajlih Tomaž , Drstvenšek Igor
Published: October 2018

Polymer products manufactured by additive processes are today increasingly flooding the market. Given that they have broad application ranging from various consumer products to medicine and automotive industry, the products must satisfy certain mechanical properties. In the past studies of selective laser sintering (SLS) for polymer materials, the processing parameter of energy density has been confirmed which affects the tensile properties. Energy density depends on the laser beam speed, laser power and hatch distance; however, in this paper the existing mathematical model has been expanded by the overlay ratio and tests have been conducted how on the basis of the new mathematical model a product with good tensile properties (tensile strength, tensile strength at break, tensile modulus, tensile strain at break) can be manufactured. However, in parameter selection as well, the layer thickness and the manufacturing strategy also play a role, and they may shorten the time and reduce the cost necessary to manufacture a new product from the initial concept to production. The paper also provides a proposal of processing parameters (laser beam speed, laser power and energy density) depending on the manufacturing strategy and layer thickness.
Optimal Design of a Two-Stage Membrane System for Hydrogen Separation in Refining Processes
Authors: Arias Ana , Mores Patricia , Scenna Nicolás , Caballero José , Mussati Sergio , Mussati Miguel
Published: October 2018

This paper fits into the process system engineering field by addressing the optimization of a two-stage membrane system for H2 separation in refinery processes. To this end, a nonlinear mathematical programming (NLP) model is developed to simultaneously optimize the size of each membrane stage (membrane area, heat transfer area, and installed power for compressors and vacuum pumps) and operating conditions (flow rates, pressures, temperatures, and compositions) to achieve desired target levels of H2 product purity and H2 recovery at a minimum total annual cost. Optimal configuration and process design are obtained from a model which embeds different operating modes and process configurations. For instance, the following candidate ways to create the driving force across the membrane are embedded: (a) compression of both feed and/or permeate streams, or (b) vacuum application in permeate streams, or (c) a combination of (a) and (b). In addition, the potential selection of an expansion turbine to recover energy from the retentate stream (energy recovery system) is also embedded. For a H2 product purity of 0.90 and H2 recovery of 90%, a minimum total annual cost of 1.764 M$·year−1 was obtained for treating 100 kmol·h−1 with 0.18, 0.16, 0.62, and 0.04 mole fraction of H2, CO, N2, CO2, respectively. The optimal solution selected a combination of compression and vacuum to create the driving force and removed the expansion turbine. Afterwards, this optimal solution was compared in terms of costs, process-unit sizes, and operating conditions to the following two sub-optimal solutions: (i) no vacuum in permeate stream is applied, and (ii) the expansion turbine is included into the process. The comparison showed that the latter (ii) has the highest total annual cost (TAC) value, which is around 7% higher than the former (i) and 24% higher than the found optimal solution. Finally, a sensitivity analysis to investigate the influence of the desired H2 product purity and H2 recovery is presented. Opposite cost-based trade-offs between total membrane area and total electric power were observed with the variations of these two model parameters. This paper contributes a valuable decision-support tool in the process system engineering field for designing, simulating, and optimizing membrane-based systems for H2 separation in a particular industrial case; and the presented optimization results provide useful guidelines to assist in selecting the optimal configuration and operating mode.
A New Home for New Immigrants? A Case Study of the Role of Soka Gakkai in the Integration of Japanese and Mainland Chinese Immigrants in Hong Kong
Authors: Ng Ka Shing
Published: October 2018

In the discussion of migrant integration into local settings, most scholars agree on the positive linkages between religion and the construction of ethnic identity. However, beyond church and mosque, there appears to be a gap in the research of the roles played by other religions in the process of migrant integration. This paper attempts to fill this gap by studying the role of a new religion Soka Gakkai (SG) in the integration of Japanese and Mainland Chinese immigrants in Hong Kong. I argue that the social and spiritual support and the ideas of a “big family” and individual empowerment (i.e., empowering oneself to overcome challenges) are important resources for immigrants when starting a new life in Hong Kong. However, the controversial image of SG might also have negative effects on SG members’ effort at integration.
3D Point Cloud Recognition Based on a Multi-View Convolutional Neural Network
Authors: Zhang Le , Sun Jian , Zheng Qiang
Published: October 2018

The recognition of three-dimensional (3D) lidar (light detection and ranging) point clouds remains a significant issue in point cloud processing. Traditional point cloud recognition employs the 3D point clouds from the whole object. Nevertheless, the lidar data is a collection of two-and-a-half-dimensional (2.5D) point clouds (each 2.5D point cloud comes from a single view) obtained by scanning the object within a certain field angle by lidar. To deal with this problem, we initially propose a novel representation which expresses 3D point clouds using 2.5D point clouds from multiple views and then we generate multi-view 2.5D point cloud data based on the Point Cloud Library (PCL). Subsequently, we design an effective recognition model based on a multi-view convolutional neural network. The model directly acts on the raw 2.5D point clouds from all views and learns to get a global feature descriptor by fusing the features from all views by the view fusion network. It has been proved that our approach can achieve an excellent recognition performance without any requirement for three-dimensional reconstruction and the preprocessing of point clouds. In conclusion, this paper can effectively solve the recognition problem of lidar point clouds and provide vital practical value.
Real-Time Traffic Risk Detection Model Using Smart Mobile Device
Authors: Park Soyoung , Han Homin , Kim Byeong-Su , Noh Jun-Ho , Chi Jeonghee , Choi Mi-Jung
Published: October 2018

Automatically recognizing dangerous situations for a vehicle and quickly sharing this information with nearby vehicles is the most essential technology for road safety. In this paper, we propose a real-time deceleration pattern-based traffic risk detection system using smart mobile devices. Our system detects a dangerous situation through machine learning on the deceleration patterns of a driver by considering the vehicle’s headway distance. In order to estimate the vehicle’s headway distance, we introduce a practical vehicle detection method that exploits the shadows on the road and the taillights of the vehicle. For deceleration pattern analysis, the proposed system leverages three machine learning models: neural network, random forest, and clustering. Based on these learning models, we propose two types of decision models to make the final decisions on dangerous situations, and suggest three types of improvements to continuously enhance the traffic risk detection model. Finally, we analyze the accuracy of the proposed model based on actual driving data collected by driving on Seoul city roadways and the Gyeongbu expressway. We also propose an optimal solution for traffic risk detection by analyzing the performance between the proposed decision models and the improvement techniques.
Depth Discrimination for Low-Frequency Sources Using a Horizontal Line Array of Acoustic Vector Sensors Based on Mode Extraction
Authors: Liang Guolong , Zhang Yifeng , Zhang Guangpu , Feng Jia , Zheng Ce
Published: October 2018

Depth discrimination is a key procedure in acoustic detection or target classification for low-frequency underwater sources. Conventional depth-discrimination methods use a vertical line array, which has disadvantage of poor mobility due to the size of the sensor array. In this paper, we propose a depth-discrimination method for low-frequency sources using a horizontal line array (HLA) of acoustic vector sensors based on mode extraction. First, we establish linear equations related to the modal amplitudes based on modal beamforming in the vector mode space. Second, we solve the linear equations by introducing the total least square algorithm and estimate modal amplitudes. Third, we select the power percentage of the low-order modes as the decision metric and construct testing hypotheses based on the modal amplitude estimation. Compared with a scalar sensor, a vector sensor improves the depth discrimination, because the mode weights are more appropriate for doing so. The presented linear equations and the solution algorithm allow the method to maintain good performance even using a relatively short HLA. The constructed testing hypotheses are highly robust against mismatched environments. Note that the method is not appropriate for the winter typical sound speed waveguide, because the characteristics of the modes differ from those in downward-refracting sound speed waveguide. Robustness analysis and simulation results validate the effectiveness of the proposed method.
Efficient AoA-Based Wireless Indoor Localization for Hospital Outpatients Using Mobile Devices
Authors: Hou Yanbin , Yang Xiaodong , Abbasi Qammer H.
Published: October 2018

The motivation of this work is to help outpatients find their corresponding departments or clinics, thus, it needs to provide indoor positioning services with a room-level accuracy. Unlike wireless outdoor localization that is dominated by the global positioning system (GPS), wireless indoor localization is still an open issue. Many different schemes are being developed to meet the increasing demand for indoor localization services. In this paper, we investigated the AoA-based wireless indoor localization for outpatients’ wayfinding in a hospital, where Wi-Fi access points (APs) are deployed, in line, on the ceiling. The target position can be determined by a mobile device, like a smartphone, through an efficient geometric calculation with two known APs coordinates and the angles of the incident radios. All possible positions in which the target may appear have been comprehensively investigated, and the corresponding solutions were proven to be the same. Experimental results show that localization error was less than 2.5 m, about 80% of the time, which can satisfy the outpatients’ requirements for wayfinding.
Digital, Rapid, Accurate, and Label-Free Enumeration of Viable Microorganisms Enabled by Custom-Built On-Glass-Slide Culturing Device and Microscopic Scanning
Authors: Song Donghui , Liu Haomin , Dong Qiuchen , Bian Zichao , Wu Huixiang , Lei Yu
Published: October 2018

Accurately measuring the number of viable microorganisms plays an essential role in microbiological studies. Since the conventional agar method of enumerating visible colonies is time-consuming and not accurate, efforts have been made towards overcoming these limitations by counting the invisible micro-colonies. However, none of studies on micro-colony counting was able to save significant time or provide accurate results. Herein, we developed an on-glass-slide cell culture device that enables rapid formation of micro-colonies on a 0.38 mm-thick gel film without suffering from nutrient and oxygen deprivation during bacteria culturing. Employing a phase contrast imaging setup, we achieved rapid microscopic scanning of micro-colonies within a large sample area on the thin film without the need of fluorescent staining. Using Escherichia coli (E. coli) as a demonstration, our technique was able to shorten the culturing time to within 5 h and automatically enumerate the micro-colonies from the phase contrast images. Moreover, this method delivered more accurate counts than the conventional visible colony counting methods. Due to these advantages, this imaging-based micro-colony enumeration technique provides a new platform for the quantification of viable microorganisms.
Detection of Micro-Defects on Metal Screw Surfaces Based on Deep Convolutional Neural Networks
Authors: Song Limei , Li Xinyao , Yang Yangang , Zhu Xinjun , Guo Qinghua , Yang Huaidong
Published: October 2018

This paper proposes a deep convolutional neural network (CNN) -based technique for the detection of micro defects on metal screw surfaces. The defects we consider include surface damage, surface dirt, and stripped screws. Images of metal screws with different types of defects are collected using industrial cameras, which are then employed to train the designed deep CNN. To enable efficient detection, we first locate screw surfaces in the pictures captured by the cameras, so that the images of screw surfaces can be extracted, which are then input to the CNN-based defect detector. Experiment results show that the proposed technique can achieve a detection accuracy of 98%; the average detection time per picture is 1.2 s. Comparisons with traditional machine vision techniques, e.g., template matching-based techniques, demonstrate the superiority of the proposed deep CNN-based one.
Nano-Antenna Coupled Infrared Detector Design
Authors: Mubarak Mohamed H. , Sidek Othman , Abdel-Rahman Mohamed R. , Mustaffa Mohd Tafir , Mustapa Kamal Ahmad Shukri , Mukras Saad M.
Published: October 2018

Since the 1940s, infrared (IR) detection and imaging at wavelengths in the two atmospheric windows of 3 to 5 and 8 to 14 μm has been extensively researched. Through several generations, these detectors have undergone considerable developments and have found use in various applications in different fields including military, space science, medicine and engineering. For the most recently proposed generation, these detectors are required to achieve high-speed detection with spectral and polarization selectivity while operating at room temperature. Antenna coupled IR detectors appear to be the most promising candidate to achieve these requirements and has received substantial attention from research in recent years. This paper sets out to present a review of the antenna coupled IR detector family, to explore the main concepts behind the detectors as well as outline their critical and challenging design considerations. In this context, the design of both elements, the antenna and the sensor, will be presented individually followed by the challenging techniques in the impedance matching between both elements. Some hands-on fabrication techniques will then be explored. Finally, a discussion on the coupled IR detector is presented with the aim of providing some useful insights into promising future work.
Antibacterial Activity of Hen Egg White Lysozyme Denatured by Thermal and Chemical Treatments
Authors: Vilcacundo Rubén , Méndez Pilar , Reyes Walter , Romero Herman , Pinto Adelita , Carrillo Wilman
Published: October 2018

The aim of this study was to increase the antibacterial spectrum of modified hen egg white lysozyme (HEWL) with thermal and chemical treatments against Gram-negative bacteria. The antibacterial activity of heat-denatured HEWL and chemical denatured HEWL against Gram-negative and Gram-positive bacteria was evaluated in 15 h of incubation tests. HEWL was denatured by heating at pH 6.0 and pH 7.0 and chemical denaturing was carried out for 1.0, 1.5, 2.0, and 4.0 h with DL-Dithiothreitol (DTT). HEWL modified by thermal and chemical treatments was characterized using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis method. Heat-denatured HEWL lytic activity against Micrococcus lysodeikticus lessened with increasing temperature and time of incubation with the chemical agent (DTT). The loss of lytic activity in modified HEWL suggests that the mechanism of action of the antibacterial activity is not dependent on the lytic activity. Thermal and chemical treatments of HEWL enabled the production of oligoforms and increased antibacterial activity over a wider spectrum. Heat-denatured HEWL at pH 6.0 and chemically-denatured HEWL increased the HEWL antibacterial spectrum against Gram-negative bacteria (Escherichia coli ATCC 25922). HEWL at 120 °C and pH 6.0 (1.0 mg/mL) inhibited 78.20% of the growth of E. coli. HEWL/DTT treatment for 4.0 h (1.0 mg/mL) inhibited 68.75% of the growth E. coli. Heat-denatured HEWL at pH 6.0 and pH 7.0 and chemically-denatured HEWL (1.0, 1.5, 2.0, and 4.0 h with DTT) were active against Gram-positive bacteria (Staphylococcus carnosus CECT 4491T). Heat-denatured and chemical-denatured HEWL caused the death of the bacteria with the destruction of the cell wall. LIVE/DEAD assays of fluorescent dye stain of the membrane cell showed membrane perturbation of bacteria after incubation with modified HEWL. The cell wall destruction was viewed using electron microscopy. The results obtained in this study suggest that heat-denatured HEWL at pH 6.0 and chemical-denatured HEWL treatments increase the HEWL antibacterial activity against Gram-negative bacteria.
Sustainable Decision Making for Store Brand Product
Authors: Choi Ji-Hung , Kim Taewan , Jung Sang-Uk
Published: October 2018

We investigate a multi-brands sustainable channel coordination problem where a national brand manufacturer sells a product through two local retailers competing against their own store brand product, respectively. We shows how the retailers strategically optimize the price and quality of private brands given the customer tastes and the production costs of the store brands in order to make their store brands sustainable. We identify two underlying strategic forces; a competitive force, and a quality force. First, we find that retailers have an incentive to position their store brand far away from the national brand in order to maximize monopolistic power. This strategic force attenuate the incentives for customer to switch to other retailer’s store brands. One the other hand, we show that the retailers prefer increasing the store brand’s quality to get more profit margin when the production cost is relatively high as well.
Low-Emission Modeling for Energy Demand in the Household Sector: A Study of Pakistan as a Developing Economy
Authors: Bashir Sana , Ahmad Iftikhar , Rashid Ahmad Sajid
Published: October 2018

In the developing world, the energy needs of the household sector have grown manifold, due to rapid urbanization and the introduction of affordable technology. However, constraints in the power supply and underutilization of renewable resources, coupled with inefficient fuel use and obsolete technology, have increased the average energy usage cost and emissions. Hence, the current study provides a long-term sustainable energy management plan for the urban household, in terms of energy savings, social cost, and greenhouse gas (GHG) mitigation. To address energy security and climate change challenges, a demand-side management scenario (DSM) is proposed through integration of efficient policies and nationally determined contributions. On the basis of policy analysis and energy consumption patterns, macro-economic modeling was carried out for the period 2011–2050, using the Long-range Energy Alternative Planning (LEAP) modeling tool. Results show that the “efficient water heating” scenario offers the maximum energy-saving potential (up to 270 M.TOE) whereas “efficient space cooling” is the lowest-cost scenario. To achieve the best-fit mitigation scenario (MIT), targets for renewable energy supply were also incorporated. Findings were weighed against the reference scenario (REF), which reveals a huge GHG reduction under the DSM. Moreover, the cost required to implement MIT is estimated to be 3.4 US $/tonne of carbon dioxide-equivalent, less than the REF.
Supporting Advances in Human-Systems Coordination through Simulation of Diverse, Distributed Expertise
Authors: Nyre-Yu Megan , Caldwell Barrett S.
Published: October 2018

Distributed expertise task environments represent a critical, but challenging, area of team performance. As teams work together to perform complex tasks, they share much information and expertise to efficiently and effectively coordinate activities. Information coordination and alignment is affected by many factors, including communication styles and distributions of domain and interaction expertise. This study was part of a series of work performed in the authors’ lab to explore feasibility of using software simulation methods as a complement to other human factors methods to explore information alignment in teams. More specifically, this study aimed to operationalize specific parameters identified in group dynamics, management, and cognitive psychology literatures. Such research can provide an operationalized model that incorporates some of these key factors in information alignment and how these factors impact overall task performance of teams in complex environments. Simulation methods were applied to explore time-based performance outcomes. Model convergence and functionality were established through a series of model-based statistical analyses, which can be later validated with supplementary field studies. Results indicate that this style of simulation modeling is feasible, and provides directions for additional examination of factors affecting team configuration, process, and performance in complex systems.
Impact of Dinophysis acuminata Feeding Mesodinium rubrum on Nutrient Dynamics and Bacterial Composition in a Microcosm
Authors: Gao Han , Hua Chenfeng , Tong Mengmeng
Published: October 2018

The development of Dinophysis populations, producers of diarrhetic shellfish toxins, has been attributed to both abiotic (e.g., water column stratification) and biotic (prey availability) factors. An important process to consider is mixotrophy of the Dinophysis species, which is an intensive feeding of the Mesodinium species for nutrients and a benefit from kleptochloroplasts. During the feeding process, the nutritional status in the environment changes due to the preference of Mesodinium and/or Dinophysis for different nutrients, prey cell debris generated by sloppy feeding, and their degradation by micro-organisms changes. However, there is little knowledge about the role of the bacterial community during the co-occurrence of Mesodinium and Dinophysis and how they directly or indirectly interact with the mixotrophs. In this study, laboratory experiments were performed to characterize the environmental changes including those of the prey present, the bacterial communities, and the ambient dissolved nutrients during the co-occurrence of Mesodinium rubrum and Dinophysis acuminata. The results showed that, during the incubation of the ciliate prey Mesodinium with its predator Dinophysis, available dissolved nitrogen significantly shifted from nitrate to ammonium especially when the population of M. rubrum decayed. Growth phases of Dinophysis and Mesodinium greatly affected the structure and composition of the bacterial community. These changes could be mainly explained by both the changes of the nutrient status and the activity of Dinophysis cells. Dinophysis feeding activity also accelerated the decline of M. rubrum and contamination of cultures with okadaic acid, dinophysistoxin-1, and pectenotoxin-2, but their influence on the prokaryotic communities was limited to the rare taxa (<0.1%) fraction. This suggests that the interaction between D. acuminata and bacteria is species-specific and takes place intracellularly or in the phycosphere. Moreover, a majority of the dominant bacterial taxa in our cultures may also exhibit a metabolic flexibility and, thus, be unaffected taxonomically by changes within the Mesodinium-Dinophysis culture system.
Mycotoxins in Tea: Occurrence, Methods of Determination and Risk Evaluation
Authors: Sedova Irina , Kiseleva Mariya , Tutelyan Victor
Published: October 2018

Tea is one of the most popular beverages all over the world. Being an everyday drink for almost everyone, for centuries tea was considered safe and healthy. However, fungal contamination of tea at any stage of commodity production can pose a serious health hazard due to the accumulation of toxic secondary metabolites of moulds. Contemporary research revealed incidences of highly contaminated samples. Mycotoxin transfer from naturally contaminated raw tea into beverage was well studied for ochratoxin A only, and the possible leak of other mycotoxins is discussed. The results of several surveys were combined to evaluate aflatoxin B1 and ochratoxin A contamination levels in black tea and Pu-erh. Exposure estimate to aflatoxin B1 and ochratoxin A due to tea consumption was carried out based on these data. Average contamination level corresponds to the exposure of 3–40% (aflatoxin B1) and 5–24% (ochratoxin A) of mean overall estimates for different cluster diets. Lack of data does not allow the conclusion for the necessity of public health protection measures. It is necessary to perform representative studies of different kinds of tea for regulated mycotoxins at least. Contemporary techniques for analysis of mycotoxins in tea are summarised in the present review.
Sur la répartition des feldspaths potassiques dans les roches éruptives et métamorphiques de la région d'Avallon
Authors: Caillère Simonne , Kraut François
Published: October 2018

Les roches acides de la région renferment les feldspaths potassiques orthose et microcline. L'orthose prédomine à l'intérieur des massifs éruptifs tandis que le microcline se concentre dans leurs zones périphériques ainsi que dans les apophyses et filons qui les accompagnent.
Reproduction artificielle de l'idocrase
Authors: Christophe Michel-Lévy Mireille
Published: October 2018

Synthèse hydrothermale de l'idocrase à 1 000 bars, 500°. Conditions de gisement. Relations avec le grenat grossulaire.
Sur les structures isovectorielles et homométriques
Authors: Garrido Julio , Munoz Ruffino
Published: October 2018

Déduction des conditions pour qu'étant donnée une structure on puisse en construire une autre différente avec les mêmes vecteurs interatomiques.

Étude systématique des structures isovectorielles et homométriques avec 3 et 4 atomes par maille. On trouve un seul type de structures homométriques à 3 atomes et 31 types à 4 atomes. Table des conditions entre les vecteurs et entre les facteurs atomiques pour l'existence de plusieurs solutions dans la détermination des structures.
Contribution à l'étude des carbonates simples anhydres
Authors: Caillère Simonne , Pobeguin Thérèse
Published: October 2018

L'étude de carbonates simples anhydres nous a permis de constater que la structure de l'ion métallique, en particulier son diamètre, jouait un rôle important dans la position et le déplacement des bandes d'absorption infrarouge. De plus la configuration électronique du cation semble conditionner les températures de dissociation de ces minéraux.
Sur le polymorphisme de la cyanoacétamide
Authors: Dejace Jules
Published: October 2018

La cyanoacétamide se présente sous trois formes polymorphes. L'une est triclinique, la deuxième, monoclinique, la troisième, stable à haute température seulement, est orthorhombique. Les dimensions réticulaires et les propriétés optiques de chaque forme sont données. Les transformations d'une phase à l'autre ont été étudiées au microscope polarisant à platine chauffante.
La symétrie des feldspaths potassiques dans les gneiss et les granites des Pyrénées orientales
Authors: Guitard Gérard , Raguin Eugène , Sabatier Germain
Published: October 2018

Étude par la diffraction des rayons X et l'optique de la symétrie des feldspaths potassiques de plusieurs séries gneissiques et granitiques des Pyrénées orientales (France), montrant les trois degrés de métamorphisme épizone, mésozone et catazone. Dans les gneiss du métamorphisme général on trouve de l'orthose dans la cata-zone ; de l'orthose et du microcline dans la mésozone. Au cours de la granitisation régionale, la nature du feldspath potassique, est liée, pour la région étudiée aux divers étages de granitisation : les granites de la catazone sont à orthose ou à microcline de faible triclinisme ; ceux de la mésozone sont à microcline fortement triclinique et ceux de l'épizone à orthose et microcline. On interprète ces résultats en admettant que le feldspath potassique cristallise toujours initialement sous forme monoclinique. Dans la catazone cette forme est stable. Dans la méso-et l'épizone, elle est métastable et tend à devenir triclinique. On discute les facteurs cinétiques qui peuvent accélérer ou, au contraire, retarder cette transformation.
Effet des radiations sur les propriétés électriques et optiques du fluorure de lithium. I. Conductivité électrique de monocristaux de fluorure de lithium non irradié
Authors: Bergé Pierre
Published: October 2018

La conductibilité électrique de LiF est mesurée entre l'ambiante et 560° C. Les résultats peuvent s'interpréter en admettant la présence de lacunes induites par des impuretés divalentes. L'énergie libre de liaison entre l'impureté et la lacune induite est 0,7-0,8 eV, l'énergie de mobilité 0,7 eV, ce qui est en accord avec les résultats antérieurs.
Phases résultant de l'attaque de bétons réfractaires par l'aluminium fondu
Authors: Bolfa Joseph , Kern Raymond
Published: October 2018

L'étude au microscope métallographique polarisant et aux rayons X a permis l'identification des phases résultant de l'attaque de deux bétons réfractaires par l'aluminium fondu à haute température. La différence de comportement des deux bétons, ciment Secar 250-corindon, ciment Secar 250-chamotte, vis-à-vis de l'aluminium fondu a été mise en évidence.
Effet des rayonnements sur les propriétés électriques du fluorure de lithium
Authors: Bergé Pierre , Blanc G.
Published: October 2018

La technique mise au point précédemment pour la détermination de la conductibilité du fluorure de lithium non irradié a été appliquée à l'étude des comportements électriques d'échantillons irradiés aux y et aux neutrons thermiques.

L'irradiation aux y diminue la conductivité. Le revenu thermique, sans cinétique apparente, peut s'interpréter en termes d'un complexe instable bâti par irradiation à partir du couple déjà décrit Mg⁺⁺, lacune lithium induite. L'irradiation aux neutrons produit des effets plus complexes se manifestant au-delà de 10¹⁵ nvt par l'augmentation de la conductivité et par un revenu en deux stades. Le premier s'accompagne d'une diminution de la conductivité correspondant probablement à l'élimination progressive de porteurs excédentaires liés, créés par irradiations. Le deuxième stade correspond au retour de la conductivité, à son comportement avant irradiation par un mécanisme de dépiégeage des porteurs normalement en équilibre thermodynamique.
Étude comparative de l'ampangabéite et de la samarskite
Authors: Van Wambeke L.
Published: October 2018

This study was done on various samples of ampangabeites and samarskites mostly by the combined X-ray diffraction-fluorescence method and also by differential thermal analyses. The X-ray fluorescence analysis was used for the determination of the chemical composition of these metamict minerals. The X-ray fluorescence pattern obtained on the inner zones were identical for both minerals, taking account of possible ionic replacement. For the weathered zone of these minerals, a pronounced lixiviation of Y and also U, Ca and the other rare earths was observed often with an enrichment of Pb.

The diffraction patterns taken after recrystallisation were identical for the inner zones of ampangabeites and samarskites and also for the weathered zones. In the case of the inner zones especially, the fundamental structure of the pyrochlore-microlite-betafite series was found in the diffraction patterns with extra lines characteristic of samarskites. The differential thermal analysis shows for the inner and non weathered zones of both minerals an exothermic peak at 710 — 715°C and for the weathered zones a peak between 670 and 685° C.

We also propose for the weathered zones of ampangabeites of samarskites a new chemical formula :

AB₂₊ₓ [O, (OH)]₆₊₂,₅ₓ nH₂O

où A = TY, TCe, U, Ca, Fe, Th, Pb et B = Nb, Ta, Ti, Sn.

This formula takes account of the hydration and the lixiviation of some chemical elements.

This study shows the identity of ampangabeite with somarskite. The differential thermal analysis shows for the inner and non weathered zones of both minerals an exothermic peak at 710 — 715°C and for the weathered zones a peak between 670 and 685° C.

We also propose for the weathered zones of ampangabeites of samarskites a new chemical formula :

AB₂₊ₓ [O, (OH)]₆₊₂,₅ₓ nH₂O

où A = TY, TCe, U, Ca, Fe, Th, Pb et B = Nb, Ta, Ti, Sn.

This formula takes account of the hydration and the lixiviation of some chemical elements.

This study shows the identity of ampangabeite with somarskite.
Étude expérimentale de la diffusion cationique dans un verre basaltique : alcalins et alcalino-terreux
Authors: Jambon Albert , Carron Jean-Paul
Published: October 2018

Experimental study of the diffusion of alkali and alkali-earth ions has been realized in a basaltic glass by the thin radioactive layer technique, in the range 750-1 000° C, and under usual conditions of pressure and oxygen fugacity. The diffusion coefficients (D) vary between 10-7 and 10-12 cm2 s_1, and they fit Arrhenius laws [D = Do exp (— E/RT)], with activation energies of 13 to 60 kcal/mole. These new results are consistent with our previous experiments on obsidians and feldspar glasses, and confirm the observed magnitudes and trends. The matrix composition has no significant effect, whereas the diffusi-vities strongly depend on the nature of the element under consideration. For most elements, an increase of temperature of 100° C results in a 5-10 fold decrease of D values, except for Na and K which vary more slowly.
Étude électrochimique de l'oxydation de la chalcopyrite en milieu acide chloruré
Authors: Ammou-Chokroum Mustapha , Steinmetz Daniel , Malvé Alain
Published: October 2018

The oxidative dissolution of copper from chalcopyrite in an acidic medium shows that the dissolution is inhibted as the mineral dissolves. The reaction mechanisms which are responsible for this inhibited phenomena are developed through electrochemical measurements of the reactivity of the mineral itself and its oxidation in a ferric medium. The elementary anodic curve of chalcopyrite in chloride media is characterised by two peaks of oxidation, the first being attributed to adsorption while the second to an oxidation leading to passivation of the solid. The chalcopyrite transforms superficially into a sulfide which is less reactive. Accordingly, the oxidation of the mineral in a ferric medium is under anodic control.
Réflectance, indice de réfraction et expression quantitative de la couleur de proustites et pyrargyrites naturelles et artificielles : interprétation génétique
Authors: Pinet Michèle , Cervelle Bernard , Desnoyers Christian
Published: October 2018

58 samples of proustite and pyrargyrite from different deposits have been studied to determine relationship between optical properties in reflected light and chemical composition obtained from electron microprobe analysis. For each natural sample, reflectance and refractive indices have been measured in the range of the visible spectrum. Comparison of these results with measurements on synthetic samples shows discrepancies between terms with the same degree of substitution. The comparison was made easier using colour parameters among which luminance was found, in this case, the more convenient.

Luminance and deposit types of pyrargyrite seem to be linked. This leads to discriminate volcanic from periplutonic occurrences. Among periplutonic occurences, it is also possible to distinguish Pb-Zn and Co-Ni-Ag parageneses.
Quelques exemples d'apports de la minéralogie à la connaissance et la recherche des gîtes minéraux
Authors: Aye Françoise , Bouladon Jean , Picot Paul , Pouit Georges
Published: October 2018

Après avoir rappelé que la minéralogie, parfois complétée par la chimie, est la première démarche du géologue prospecteur, plusieurs exemples sont donnés montrant son intérêt en gîtologie et donc son rôle dans la recherche minière moderne. Les associations minéralogiques globales et les paragenèses permettent une meilleure connaissance du type des gisements, du chimisme de la province et de la zonalité du corps minéralisé, du district ou de la province. A cet aspect qualitatif et quantitatif de la minéralogie, il convient d'ajouter l'étude géochimique des minéraux qui représente une voie relativement nouvelle de recherche susceptible d'application pratique.
L'interdépendance du monde des minéraux et de la matière vivante
Authors: Wyckoff Ralph Walter Graystone
Published: October 2018

Certaines relations étroites sont indiquées entre le monde des minéraux et la matière vivante qui provient des substances minérales et en revanche les altère. L'échange est noté pour chaque élément chimique essentiel et pour les éléments utilisés en trace. La diminution de nos ressources naturelles produit des déséquilibres qui peuvent être corrigés en utilisant au plus haut degré les ressources qui nous restent. Toutefois l'avenir de notre civilisation dépend de l'application du savoir nouveau qui ne peut provenir que du développement vigoureux de la science naturelle.
Les types paragénétiques des amphiboles sodiques dans les roches magmatiques
Authors: Fabriès Jacques
Published: October 2018

In sodic amphiboles of igneous origin, Fe3+ ions are more abundant than Al3+ in the occupancy of the octahedral sites, even in varieties showing a great substitution of Al for Si in tetrahedral sites. On the other hand the Mg/Fe2+ ratio ranges are much more extended. The magnesium-rich alkali amphiboles are essentially richteritic : (1) potassic richterites in some ultramafic xenoliths of kimberlites and in highly potassic volcanic rocks (orenditic lamproites) ; (2) richterite-magnesioarfvedsonite solid solutions in carbonatites and related rocks.

The paragenetic types of iron-rich or intermediate alkali amphiboles follow three main fractionation trends. In the series that follow a miaskitic evolution, the amphibole changes hastingsite to taramite, where NaFe3+ mainly substitutes for CaFe2+. The agpaitic alkaline series show the sequence kataphorite arfvedsonite → riebeckite-arfvedsonite, corresponding to NaSi → CaAl and F- OH-substitutions ; the Ca/Al ratio hardly deviates from one in all the amphiboles of the sequence. The amphiboles from supersatured alkaline series follow a fractionation trend richterite-katophorite → arfvedsonite → riebeckite-arfvedsonite, governed by the two main substitutions NaR3+ → CaR2+ and NaSi → CaAl. The Ca/Al ratio in this case is around two. Therefore SiO2 activity, as well as temperature, total pressure and oxygen fugacity, plays a major role in controlling the solubility of aluminium in sodic amphiboles, as well as in hornblendes.
Développement récents dans la mesure au microscope des réflectances spectrales des minéraux opaques
Authors: Cervelle Bernard , Lévy Claude , Henry Norman-Fordyce-McKerron , Shadlun Tatiana N.
Published: October 2018

La mesure des réflectances a connu un développement considérable ces quinze dernières années en raison des améliorations apportées aux appareillages de microphotométrie et de la standardisation des méthodes de mesure effectuée par la Commission on Ore Microscopy (COM-IMA). Après un exposé de ces méthodes, on présente : 1) les résultats obtenus dans l'établissement des tables et abaques pour l'identification des minéraux des minerais ; 2) les travaux de nature plus fondamentale et concernant les propriétés optiques des cristaux absorbants ; 3) les résultats obtenus dans la mesure de ces propriétés optiques pour leur utilisation en gîtologie et en géochimie. Dans un chapitre séparé, sont présentés les importants résultats obtenus en Union Soviétique. On termine en présentant les développements récents et les perspectives d'avenir de la microréflectométrie, et en fournissant une large bibliographie.
Quelques applications de la microsonde électronique et de l'analyseur ionique en Minéralogie
Authors: Castaing Raymond , Bizouard Hélène , Clocchiatti Roberto , Havette Ledebt Andrée
Published: October 2018

New possibilities have been opened in the field of Earth Sciences by the development of modern techniques of point analysis ; this paper is concerned with two of them : microprobe analysis, which is now used routinely in most mineralogical laboratories, and ion emission analysis which makes possible isotopical as well as chemical identification.

Both techniques are briefly outlined, with special emphasis on their specific advantages and limitations. A few typical applications : quantitative analysis, identification of unknown phases, mapping of the constituent elements in a mineral, zoning studies, local measurements of isotopic ratios... are presented as illustrations. A study of the so-called «melt inclusions » is discussed in more detail as an example of a joint application of microprobe and ion analysis.
Application de la microscopie électronique à la minéralogie. I. Microscopie électronique en transmission (M. E. T.)
Authors: Eberhart Jean-Pierre , Gandais Madeleine , Willaime Christian
Published: October 2018

Après un rappel du principe du microscope électronique en transmission, on présente son utilisation dans l'étude des minéraux. On montre en particulier les techniques de préparation propres aux échantillons minéraux et on donne des exemples des différents travaux effectués sur des minéraux, tant en utilisant la diffraction que les contrastes d'images ou la haute résolution.
L'analyse quantitative d'images et ses applications à la minéralogie
Authors: Gateau Christian
Published: October 2018

The use of quantitative images analysers in mineralogical applications allows the processing of optical observations with a mathematical rigour.

We briefly mention and illustrate the different geometrical parameters which can be determined as well as some fields of applications of the method.

The accuracy and the variety of the informations available are well fitted with ore deposits studies.
L'indice plombo-antimonifère de Bestrée (cap Sizun, Finistère)
Authors: Moëlo Yves , Fouquet Yves , Laforêt Claude , Chauris Louis
Published: October 2018

Le petit indice à antimoine et plomb de Bestrée (Finistère) constitue la meilleure occurrence française de fiilôppite. Trois phases s'y succèdent : la première à stibine, la seconde à zinkénite, blende et sulfosels du groupe de la plagionite, la troisième à jamesonite, pyrite framboïdale et galène fortement antimonifère. L'évolution de la succession de la stibine à la galène et son télescopage à échelle réduite représentent un phénomène très rare.