bluuebunny/crossref_metadata_2025 huggingface dataset:
Two Different Scenarios for the Equilibration of Polycation—Anionic Solutions at Water–Vapor Interfaces
Authors: Guzmán Eduardo , Fernández-Peña Laura , Akanno Andrew , Llamas Sara , Ortega Francisco , G. Rubio Ramón
Published: July 2019

The assembly in solution of the cationic polymer poly(diallyldimethylammonium chloride) (PDADMAC) and two different anionic surfactants, sodium lauryl ether sulfate (SLES) and sodium N-lauroyl-N-methyltaurate (SLMT), has been studied. Additionally, the adsorption of the formed complexes at the water–vapor interface have been measured to try to shed light on the complex physico-chemical behavior of these systems under conditions close to that used in commercial products. The results show that, independently of the type of surfactant, polyelectrolyte-surfactant interactions lead to the formation of kinetically trapped aggregates in solution. Such aggregates drive the solution to phase separation, even though the complexes should remain undercharged along the whole range of explored compositions. Despite the similarities in the bulk behavior, the equilibration of the interfacial layers formed upon adsorption of kinetically trapped aggregates at the water–vapor interface follows different mechanisms. This was pointed out by surface tension and interfacial dilational rheology measurements, which showed different equilibration mechanisms of the interfacial layer depending on the nature of the surfactant: (i) formation layers with intact aggregates in the PDADMAC-SLMT system, and (ii) dissociation and spreading of kinetically trapped aggregates after their incorporation at the fluid interface for the PDADMAC-SLES one. This evidences the critical impact of the chemical nature of the surfactant in the interfacial properties of these systems. It is expected that this work may contribute to the understanding of the complex interactions involved in this type of system to exploit its behavior for technological purposes.
The Influence of Surface Treatment of PVD Coating on Its Quality and Wear Resistant
Authors: Zlamal Tomas , Mrkvica Ivan , Szotkowski Tomas , Malotova Sarka
Published: July 2019

The article deals with a determination of the influence of a cutting edge preparation on the quality and wear resistance of coated cutting tools. Cutting inserts made from a sintered carbide with a deposited layer of PVD coating were selected for measurement. Non-homogeneity caused by the creation of droplets arises in the application layer during the process of applying the coating by the PVD method. These droplets make the surface roughness of the PVD coating worse, increase the friction and thereby the thermal load of the cutting tool as well. Also, the droplets could be the cause of the creation and propagation of droplets in the coating and they can cause quick cutting tool wear during machining. Cutting edge preparations were suggested for the improvement of the surface integrity of deposited layers of PVD coating, namely the technology of drag finishing and abrasive jet machining. After their application, the areal surface roughness was measured on the surface of coated cutting inserts, the occurrence of droplets was tracked and the surface structure was explored. A tool-life test of cutting inserts was carried out for verification of the influence of surface treatment on the wear resistance of cutting inserts during the milling process. The cutting inserts with a layer of PVD coatings termed as samples A, B, and C were used for the tool-life test. The first sample, A, represented the coating before the application of cutting edge preparations and samples B and C were after the application of the cutting edge preparation. A carbon steel termed C45 was used for the milling process and cutting conditions were suggested. The visual control of surface of cutting inserts, intensity of wear and occurrence of thermal cracks in deposited PVD layers were the criterion for the evaluation of the individual tests.
Experimental Evidence for Partially Dehydrogenated ε-FeOOH
Authors: Zhuang Yukai , Cui Zhongxun , Zhang Dongzhou , Liu Jin , Tao Renbiao , Hu Qingyang
Published: July 2019

Hydrogen in hydrous minerals becomes highly mobile as it approaches the geotherm of the lower mantle. Its diffusion and transportation behaviors under high pressure are important in order to understand the crystallographic properties of hydrous minerals. However, they are difficult to characterize due to the limit of weak X-ray signals from hydrogen. In this study, we measured the volume changes of hydrous ε-FeOOH under quasi-hydrostatic and non-hydrostatic conditions. Its equation of states was set as the cap line to compare with ε-FeOOH reheated and decompression from the higher pressure pyrite-FeO2Hx phase with 0 < x < 1. We found the volumes of those re-crystallized ε-FeOOH were generally 2.2% to 2.7% lower than fully hydrogenated ε-FeOOH. Our observations indicated that ε-FeOOH transformed from pyrite-FeO2Hx may inherit the hydrogen loss that occurred at the pyrite-phase. Hydrous minerals with partial dehydrogenation like ε-FeOOHx may bring it to a shallower depth (e.g., < 1700 km) of the lower mantle.
Anomalous Behaviors of Spin Waves Studied by Inelastic Light Scattering
Authors: Hou Hua-Yi , Yang Ming , Qiu Jin , Yang In-Sang , Chen Xiang-Bai
Published: July 2019

Magnonics, an emerging research field, aims to control and manipulate spin waves in magnetic materials and structures. However, the current understanding of spin waves remains quite limited. This review attempts to provide an overview of the anomalous behaviors of spin waves in various types of magnetic materials observed thus far by inelastic light scattering experiments. The anomalously large asymmetry of anti-Stokes to Stokes intensity ratio, broad linewidth, strong resonance effect, unique polarization selection, and abnormal impurity dependence of spin waves are discussed. In addition, the mechanisms of these anomalous behaviors of spin waves are proposed.
Perspective of Molecular Diagnosis in Healthcare: From Barcode to Pattern Recognition
Authors: He Qian , Bao Mengdi , Hass Kenneth , Lin Wenxia , Qin Peiwu , Du Ke
Published: July 2019

Barcode technology has a broad spectrum of applications including healthcare, food security, and environmental monitoring, due to its ability to encode large amounts of information. With the rapid development of modern molecular research, barcodes are utilized as a reporter with different molecular combinations to label many biomolecular targets, including genomic and metabolic elements, even with multiplex targeting. Along with the advancements in barcoded bioassay, the improvements of various designs of barcode components, encoding and decoding strategies, and their portable adoption are indispensable in satisfying multiple purposes, such as medical confirmation and point-of-care (POC) testing. This perspective briefly discusses the current direction and progress of barcodes development and provides a hypothesis for barcoded bioassay in the near future.
A Novel Method for Intelligent Single Fault Detection of Bearings Using SAE and Improved D–S Evidence Theory
Authors: Lu Jianguang , Zhang Huan , Tang Xianghong
Published: July 2019

In order to realize single fault detection (SFD) from the multi-fault coupling bearing data and further research on the multi-fault situation of bearings, this paper proposes a method based on features self-extraction of a Sparse Auto-Encoder (SAE) and results fusion of improved Dempster–Shafer evidence theory (D–S). Multi-fault signal compression features of bearings were extracted by SAE on multiple vibration sensors’ data. Data sets were constructed by the extracted compression features to train the Support Vector Machine (SVM) according to the rule of single fault detection (R-SFD) this paper proposed. Fault detection results were obtained by the improved D–S evidence theory, which was implemented via correcting the 0 factor in the Basic Probability Assignment (BPA) and modifying the evidence weight by Pearson Correlation Coefficient (PCC). Extensive evaluations of the proposed method on the experiment platform datasets showed that the proposed method could realize single fault detection from multi-fault bearings. Fault detection accuracy increases as the output feature dimension of SAE increases; when the feature dimension reached 200, the average detection accuracy of the three sensors for bearing inner, outer, and ball faults achieved 87.36%, 87.86% and 84.46%, respectively. The three types’ fault detection accuracy—reached to 99.12%, 99.33% and 98.46% by the improved Dempster–Shafer evidence theory (IDS) to fuse the sensors’ results—is respectively 0.38%, 2.06% and 0.76% higher than the traditional D–S evidence theory. That indicated the effectiveness of improving the D–S evidence theory by evidence weight calculation of PCC.
A Hybrid Information Reconciliation Method for Physical Layer Key Generation
Authors: Li Guyue , Zhang Zheying , Yu Yi , Hu Aiqun
Published: July 2019

Physical layer key generation (PKG) has become a research focus as it solves the key distribution problem, which is difficult in traditional cryptographic mechanisms. Information reconciliation is a critical process in PKG to obtain symmetric keys. Various reconciliation schemes have been proposed, including the error detection protocol-based approach (EDPA) and error correction code-based approach (ECCA). Both EDPA and ECCA have advantages and drawbacks, regarding information leakage, interaction delay, and computation complexity. In this paper, we choose the BBBSS protocol from EDPA and BCH code from ECCA as a case study, analyzing their comprehensive efficiency performance versus pass number and bit disagreement ratio (BDR), respectively. Next, we integrate the strength of the two to design a new hybrid information reconciliation protocol (HIRP). The design of HIRP consists of three main phases, i.e., training, table lookup, and testing. To comprehensively evaluate the reconciliation schemes, we propose a novel efficiency metric to achieve a balance of corrected bits, information leakage, time delay, and computation time, which represents the effectively corrected bits per unit time. The simulation results show that our proposed method outperforms other reconciliation schemes to improve the comprehensive reconciliation efficiency. The average improvement in efficiency is 2.48 and 22.36 times over the BBBSS and BCH code, respectively, when the range of the BDR is from 0.5% to 11.5%. Compared to the BBBSS protocol and the BCH code, HIRP lies at a mid-level in terms of information leakage and computation time cost. Besides, with the lowest time delay cost, HIRP reaches the highest reconciliation efficiency.
Heat Transfer Coefficients Analysis in a Helical Double-Pipe Evaporator: Nusselt Number Correlations through Artificial Neural Networks
Authors: Parrales Arianna , Hernández-Pérez José , Flores Oliver , Hernandez Horacio , Gómez-Aguilar José , Escobar-Jiménez Ricardo , Huicochea Armando
Published: July 2019

In this study, two empirical correlations of the Nusselt number, based on two artificial neural networks (ANN), were developed to determine the heat transfer coefficients for each section of a vertical helical double-pipe evaporator with water as the working fluid. Each ANN was obtained using an experimental database of 1109 values obtained from an evaporator coupled to an absorption heat transformer with energy recycling. The Nusselt number in the annular section was estimated based on the modified Wilson plot method solved by an ANN. This model included the Reynolds and Prandtl numbers as input variables and three neurons in their hidden layer. The Nusselt number in the inner section was estimated based on the Rohsenow equation, solved by an ANN. This ANN model included the numbers of the Prandtl and Jackob liquids as input variables and one neuron in their hidden layer. The coefficients of determination were R 2 > 0.99 for both models. Both ANN models satisfied the dimensionless condition of the Nusselt number. The Levenberg–Marquardt algorithm was chosen to determine the optimum values of the weights and biases. The transfer functions used for the learning process were the hyperbolic tangent sigmoid in the hidden layer and the linear function in the output layer. The Nusselt numbers, determined by the ANNs, proved adequate to predict the values of the heat transfer coefficients of a vertical helical double-pipe evaporator that considered biphasic flow with an accuracy of ±0.2 for the annular Nusselt and ±4 for the inner Nusselt.
Designing Adaptive Online Mathematics Course Based on Individualization Learning
Authors: Konnova Larisa , Lipagina Larisa , Postovalova Galina , Rylov Alexander , Stepanyan Irina
Published: July 2019

The article provides a possible option of how first-year students of Russian universities adapt to mastering higher mathematics. The purpose of the research is the development of methodological approaches to designing an online course that recaps school math material in a short period. The concept of individualization of educational activities is used as the main design method. Online training is used as the implementation technology. The article provides an overview of scientific papers on the use of an individual approach to learning and online resources in teaching mathematics. The social survey of first-year students confirmed the relevance of the stated purpose. The authors describe the design methodologies of the online training by taking into account age, social and psychological characteristics of students, and the opportunity for developing individual educational trajectories. The authors set the objectives of the course and structuralize each topic. Instructional content is developed in accordance with step-by-step leveling on mastering educational material. Extra attention is given toward presenting educational information in ways that take into account different types of cognitive processes. Foreign students who receive education in Russian universities are also welcomed to the online course to get familiar with the mathematical terminology in the Russian language.
A Surface-Potential-Based Analytical I-V Model of Full-Depletion Single-Gate SOI MOSFETs
Authors: Xu Chuanzhong , Yu Fei , Huang Gongyi , Deng Wanling , Ma Xiaoyu , Huang Junkai
Published: July 2019

A surface-potential-based analytical I-V model of single-gate (SG) silicon-on-insulator (SOI) MOSFETs in full-depletion (FD) mode is proposed and compared with numerical data and Khandelwal’s experimental results. An explicit calculation scheme of surface potential, processing high computation accuracy and efficiency, is demonstrated according to the derivation of the coupling relation between surface potential and back-channel potential. The maximum absolute error decreases into 10−7 V scale, and computation efficiency is improved substantially compared with numerical iteration. Depending on the surface potential, the drain current is derived in closed-form and validated by Khandelwal’s experimental data. High computation accuracy and efficiency suggest that this analytical I-V model displays great promise for SOI device optimizations and circuit simulations.
Elimination of Motion-Induced Phase Based on Double-Time Switching Scheme for SAA FMCW Radar
Authors: Lin Yi , Yang Kai , Guo Min , Fu Yunqi
Published: July 2019

Due to the low cost and straightforward structure, the switch antenna array (SAA) frequency modulated continuous wave (FMCW) radar has been widely applied in many fields. However, the motion-induced phase always leads to inaccurate direction estimation of moving targets. Here, we proposed an elimination method of the motion-induced phase for the SAA FMCW radar. A double-time switching scheme (DTSS) is used for the reception of echo signals. Elimination of motion-induced phase is completed without estimating velocity, which can avoid the ambiguous velocity estimation problem. Additionally, the direction estimation of the moving target can be obtained by directly using a conventional digital beam forming (DBF) algorithm. The validity of the proposed method has been proved by the simulated and experimental results.
Nickel Particle-Based Compact Flexible Antenna for Modern Communication Systems
Authors: Rahman Md. Atiqur , Faruque Mohammad Rashed Iqbal , Ahamed Eistiak , Islam Mohammad Tariqul , Singh Mandeep
Published: July 2019

A flexible antenna is a significant part of the new generation of wireless communication systems. Conventional antennas are typically fabricated on available FR-4 and RT/Duroid dielectric materials, where the dielectric constant cannot be selected arbitrarily and the degrees of freedom in designing the antenna are limited, whereas our flexible substrate offers moderate dielectric values by changing the concentration of the raw materials. Synthesised nickel particle-based flexible nickel aluminate (NiAl2O4) is utilized as a substrate material to make an effective antenna for microwave applications. The nickel aluminate substrate was made with 42% concentration of nickel, and has a dielectric constant of 4.979 and a thickness of 1 mm. The fabricated flexible antenna shows measured bandwidth from 6.50–8.85 GHz. On the other hand, the maximum measured gain and efficiency was 4.75 dBi and 91%, respectively. Finally, that antenna has directional radiation patterns and the presented antenna has a novelty where the nickel aluminate substrate was used for the first time. Thus the compactness of the antenna and its performance with a flexible nature makes it a worthy one to be used in the C-band application.
Task Scheduling to Constrain Peak Current Consumption in Wearable Healthcare Sensors
Authors: Sherratt Robert Simon , Janko Balazs , Hui Terence , Harwin William S. , Dey Nilanjan , Díaz-Sánchez Daniel , Wang Jin , Shi Fuqian
Published: July 2019

Small embedded systems, in our case wearable healthcare devices, have significant engineering challenges to reduce their power consumption for longer battery life, while at the same time supporting ever-increasing processing requirements for more intelligent applications. Research has primarily focused on achieving lower power operation through hardware designs and intelligent methods of scheduling software tasks, all with the objective of minimizing the overall consumed electrical power. However, such an approach inevitably creates points in time where software tasks and peripherals coincide to draw large peaks of electrical current, creating short-term electrical stress for the battery and power regulators, and adding to electromagnetic interference emissions. This position paper proposes that the power profile of an embedded device using a real-time operating system (RTOS) will significantly benefit if the task scheduler is modified to be informed of the electrical current profile required for each task. This enables the task scheduler to schedule tasks that require large amounts of current to be spread over time, thus constraining the peak current that the system will draw. We propose a solution to inform the task scheduler of a tasks’ power profile, and we discuss our application scenario, which clearly benefited from the proposal.
Adaptive Command-Filtered Backstepping Control for Virtual Synchronous Generators
Authors: Yang Chengshun , Yang Fan , Xu Dezhi , Huang Xiaoning , Zhang Dongdong
Published: July 2019

Distributed energy sources are usually interfaced to the grid using power electronic converters, and lack of inertia in inverter dominated microgrids can affect the system stability. This paper presents a new method for virtual synchronous generator (VSG) control in order to solve the low system inertia and support the grid frequency problem. In this paper, the VSG based on electromagnetic transient characteristics is improved and an adaptive command filter back-stepping controller is designed. Firstly, the rotor swing equation and power part are modeled to complete the controller design for achieving system stability in the islanded, grid-connected and transition modes. In addition, a limited-amplitude command filter is used to deal with computational complexity and nonlinear saturation problems in the design process. Secondly, projection operator, and adaptive inertia and damping control are introduced to reduce the modeling error and disturbance caused by changing parameters. This ensures the boundedness of the estimated value and further improves the frequency response, especially in the transition mode. Finally, simulation results show that the proposed controller is more effective than the traditional control method for achieving power stability and frequency improvement.
Exploring Nonlinear Intra-Annual Growth Dynamics in Fagus sylvatica L. Trees at the Italian ICP-Forests Level II Network
Authors: Ferrara Carlotta , Marchi Maurizio , Fabbio Gianfranco , Fares Silvano , Bertini Giada , Piovosi Maurizio , Salvati Luca
Published: July 2019

The European beech (Fagus sylvatica L.) is a widely distributed tree species across Europe, highly sensitive to climate change and global warming. This study illustrates results of a 5-year monitoring time period from eight sites of the ICP-Forests Level II (intensive monitoring network) along the Italian latitudinal gradient. The tree-level relationship between tree growth dynamics and environmental factors, including seasonal climate fluctuations were investigated by means of tree-level Generalized Additive Mixed Models (GAMMs). Model results revealed that climate was responsible for just a portion of the variability in beech growth dynamics. Even if climatic predictors were highly significant in almost all sites, the model explained nearly 30% of the total variance (with just a maximum value of 71.6%), leaving the remaining variance unexplained and likely connected with forest management trajectories applied to each site (e.g., aged coppice and fully grown high forest). Climate change scenarios were then applied to predict site-specific future responses. By applying climate change scenarios, it was predicted that central and northern Italy would face similar climatic conditions to those currently detected at southern latitudes. A special case study was represented by VEN1 plot (Veneto, Northern Italy) whose current and future climate regimes were grouped in a unique and separated cluster.
On the Effect of Heat Treatments on the Adhesion, Finishing and Decay Resistance of Japanese cedar (Cryptomeria japonica D. Don) and Formosa acacia (Acacia confuse Merr.(Leguminosae))
Authors: Chang Chia-Wei , Kuo Wei-Ling , Lu Kun-Tsung
Published: July 2019

In Taiwan, it is important to maintain sustainable development of the forestry industry in order to raise the self-sufficiency of domestic timber. Japanese cedar (Cryptomeria D. Don and Formosa acacia (Acacia confusa Merr.(Leguminosae)) have abundant storage options and are the potential candidates for this purpose. Heat treatment is a new environment-friendly method used to enhance the dimensional stability and durability of wood. On treatment, a surface with new characteristics is produced because of wood component changes. Consequently, an inactivated surface and a weak boundary layer are generated, and the wettability for adhesives and coatings is reduced. Furthermore, it decreases the pH value of the wood surface, and results in delay or acceleration during the curing of adhesives. This phenomenon must be paid attention to for practical applications of heat-treated wood. Ideal heat-treated conditions of C. japonica and A. confusa woods with productive parameters such as temperature, holding time, heating rate, and thicknesses of wood were identified in our previous study. In this research work, we focus on the normal shear strength of heat-treated wood with adhesives such as urea-formaldehyde resin (UF) and polyvinyl acetate (PVAc), and the finishing performances of heat-treated wood with polyurethane (PU) and nitrocellulose lacquer (NC) coatings as well as assessing the decay-resistance of heat-treated wood. The results show that heat-treated wood had a better decay resistance than untreated wood. The mass decrease of heat-treated wood was only 1/3 or even less than the untreated wood. The normal shear strength of heat-treated wood with UF and PVAc decreased from 99% to 72% compared to the untreated wood, but the wood failure of heat-treated wood was higher than that of the untreated one. Furthermore, the adhesion and impact resistance of wood finished by PU and NC coatings showed no difference between the heat-treated wood and untreated wood. The finished heat-treated wood had a superior durability and better gloss retention and lightfastness than that of the untreated wood.
Assessment of the Seismic Site Amplification in the City of Ivanec (NW Part of Croatia) Using the Microtremor HVSR Method and Equivalent-Linear Site Response Analysis
Authors: Stanko Davor , Markušić Snježana , Gazdek Mario , Sanković Vedran , Slukan Ivan , Ivančić Ines
Published: July 2019

The city of Ivanec is located between valley of the Bednja River and Mt. Ivanščica and this area can be prone to significant seismic site amplification due to local site characteristics. This study presents the first assessment of seismic site amplification for the city of Ivanec by the microtremor horizontal-to-vertical-spectral-ratio (HVSR) method and the equivalent-linear (EQL) site response analysis. Based on microtremor measurements and HVSR analysis, fundamental soil frequency and HVSR peak amplitude maps indicate potentially seismic danger zones. The 1-D EQL site response analysis was performed using multiple suites of earthquake ground motions scaled to the 95- and 475-year return periods of peak ground accelerations. Site amplification maps at the predominant peak frequency and ground surface indicate two microzones, one with high amplification in the central part of the city due to soft soil characteristics, and the other with small amplification in the transitional zone from alluvial basin towards the foothills of Mt. Ivanščica. HVSR peak amplitudes and site response peak amplifications showed similar spatial distributions with similar predominant peak frequencies but with different amplitude levels. Site amplification maps provided significant information about potential resonance effects for structures of certain heights that can be correlated with the local ground shaking characteristics.
Identification of MVOCs Produced by Coniophora puteana and Poria placenta Growing on WPC Boards by Using Subtraction Mass Spectra
Authors: Kozicki Mateusz , Wiejak Anna , Piasecki Michał , Abram Alicja
Published: July 2019

Volatile fungal metabolites are responsible for various odors and may contribute to a “sick building syndrome” (SBS) with a negative effect on the heath of building. The authors have attempted to fill the research gaps by analyzing microbial volatile organic compounds (MVOCs) originating from representatives of the Basidiomycetes class that grow on wood-polymer composite (WPC) boards. WPCs have been analyzed as a material exposed to biodeterioration. Indoor air quality (IAQ) is affected by the increased use of WPCs inside buildings, and is becoming a highly relevant research issue. The emission profiles of MVOCs at various stages of WPC decay have been demonstrated in detail for Coniophora puteana and Poria placenta, and used to set the European industrial standards for wood-decay fungi. Differences in the production of MVOCs among these species of fungi have been detected using the thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) method. This study identifies the production of alcohols, aldehydes, ketones, carboxylic acids and other compounds during one month of fungal growth. The identified level of metabolites indicates a relation between the level of air pollution and condition of the WPC material, which may become part of IAQ quantification in the future. The study points to the species-specific compounds for representatives of brown and white-rot fungi and the compounds responsible for their odor. In this study, 1-Octen-3-ol was indicated as a marker for their active growth, which is also associated with SBS. The proposed experimental set-up and data analysis are a simple and convenient way to obtain emission profiles of MVOCs from microbes growing on different materials.
Video Display Operator Complaints: A 10-Year Follow-Up of Visual Fatigue and Refractive Disorders
Authors: Larese Filon Francesca , Drusian Anna , Ronchese Federico , Negro Corrado
Published: July 2019

Visual fatigue and discomfort are very common complaints for video display operators (VDTs). The aim of our study was to study work-related visual symptoms in relation to refractive disorders and psychosocial factors in 3054 public employees by way of follow-ups for 10 years with periodic medical examinations with eye evaluation in the period 2000–2009. Factors related to visual fatigue were evaluated in the follow-up using generalized equation estimation. Visual fatigue was very common in VDT operators (64.03%). During the follow-up, no relationship between visual fatigue and age, sex, seniority of work, visual acuity and refractory disorders was found. Visual fatigue was significantly associated with anxiety perception in a dose-related matter (odds ratio (OR) 7.40, confidence interval (CI) 95% 1.77–31.3), psychosocial factors (OR 1.03, CI 95% 1.01–1.07), use of lenses (OR 1.34, CI 95% 1.09–1.64) and time of VDT usage (OR 1.27, CI 95% 1.04–1.53). This study confirmed that visual fatigue is common in VDT users and is related to anxiety perception, time of VDT usage, use of lenses and stress. No relationship was found between visual fatigue and refractory disorders or visual acuity.
Living Well with Pollution? The Impact of the Concentration of PM2.5 on the Quality of Life of Patients with Asthma
Authors: Ścibor Monika , Galbarczyk Andrzej , Jasienska Grazyna
Published: July 2019

While the negative influence of environmental pollution on the respiratory system is well established, especially for people with bronchial hyper-reactivity, the impact of particulate matter on quality of life in asthma patients is not well understood. Three hundred adult asthma patients were recruited for a study; for each patient, the daily concentrations of particulate matter of 2.5 µm or less in diameter (PM2.5) were recorded from air quality monitoring stations. The study was conducted over two weeks. After two weeks, the patients filled out the Asthma Quality of Life Questionnaire (AQLQ), evaluating the quality of their lives throughout the monitored period. Patients exposed to a higher concentration of PM2.5 had significantly lower AQLQ scores. Every 10 µg/m3 of an increase in the concentration of PM2.5 resulted in a decrease of the AQLQ score by 0.16. All domains of quality of life (symptoms, activity limitations, emotional functioning, and environmental stimuli) assessed in the questionnaire were negatively affected by PM2.5. These findings provide an important argument in favor of educating physicians and patients and raising awareness about the detrimental health effects of air pollution. Improving the quality of life of people with asthma requires an immediate and substantial reduction of air pollution.
The Transfer Characteristics of Potentially Toxic Trace Elements in Different Soil-Rice Systems and Their Quantitative Models in Southeastern China
Authors: Yu Zheyao , Dong Jiaqi , Fu Weijun , Ye Zhengqian , Li Wanyi , Zhao Keli
Published: July 2019

The potentially toxic trace elements (PTEs) transfer characteristics in the soil-rice system plays an important role in soil quality management, and it can be used to guide the safe rice production. We collected soil and rice samples from three typical rice production areas (Nanxun, Shengzhou, Wenling in northern, central, and southern parts of Zhejiang Province, China). The controlling factors of PTEs′ transfer were studied for Hybrid rice and Japonica rice. The results indicated that the pH, organic matter (OM), and electrical conductivity (EC) values of Shengzhou were all lower than that of the other two production areas (Nanxun and Wenling). The concentrations of PTEs in the soils of Wenling were significantly higher than that in the other two areas, while the concentrations of PTEs in the rice of Shengzhou were significantly higher than that of Wenling and Nanxun (p < 0.05). The enrichment index (EI) of PTEs were also different in the three production areas. The EIs of Cd and Zn were higher than that of Cu and Ni in the three production areas, and the EIs in Shengzhou were significantly higher than that of other two areas (p < 0.05). The soil physico-chemical properties and PTEs’ fractions both played important roles in PTEs transfer in the soil-rice system. The log-linear model of EI for PTEs can predict the availability of PTEs in the soil-rice system under practical production areas. The accuracy of the model prediction of EI for Japonica rice was better than that for the Hybrid rice. The prediction model of Ni was better than that of other PTEs for both rices.
Bone Mineral Density and Bone Turnover Markers in Postmenopausal Women Subjected to an Aqua Fitness Training Program
Authors: Wochna Krystian , Nowak Alicja , Huta-Osiecka Anna , Sobczak Katarzyna , Kasprzak Zbigniew , Leszczyński Piotr
Published: July 2019

The purpose of this study was to analyze the influence of aqua fitness training in deep water on bone tissue. The study was performed with 18 postmenopausal women separated into two groups: training and control groups. Before and after the training program, the hip and spine areal bone mineral density were measured along with the biochemical parameters of serum concentration of osteocalcin (OC) and C-terminal telopeptide of type I collagen (CTX). The most significant effect was found in differences between the two groups of women in terms of femur strength index (p < 0.05) during the period of the training program. The study demonstrated that an aqua fitness training program caused favorable changes in femur strength index in postmenopausal women, and this kind of exercise could be a useful form of physical activity for postmenopausal women.
Attribution of Runoff Variation in the Headwaters of the Yangtze River Based on the Budyko Hypothesis
Authors: Liu Junlong , Chen Jin , Xu Jijun , Lin Yuru , Yuan Zhe , Zhou Mingyuan
Published: July 2019

Quantifying the contributions of climate change and human activities on runoff changes is of great importance for water resource management, sustainable water resource utilization, and sustainable development of society. In this study, hydrological and climatic data from hydrological and meteorological stations in the headwaters of the Yangtze River (YRHA) from 1966 to 2013 were used to quantitatively attribute the runoff change to the impacts of climate change and human activities separately. Firstly, the change trends in precipitation, runoff depth and potential evapotranspiration were analyzed by the Mann-Kendall test method. Three methods, secondly, including ordered clustering, Mann-Kendall and cumulative anomaly curve were adopted to detect the change points of runoff at Zhimenda hydrological station and partition the whole study period into two sub-periods at the change point (base and impacted periods). Then, the elasticity coefficient method based on the Budyko hypothesis was applied to calculate elasticity coefficients of runoff to precipitation, potential evapotranspiration and land use/cover during the two periods, and to evaluate the contributions of climate change and human activities. Results indicated that during 1966–2013, runoff depth, precipitation and potential evapotranspiration all showed a significant increasing trend, with increasing rates of 7.26 mm decade−1, 18.725 mm decade−1 and 7.228 mm decade−1, respectively. One change point (2004) was detected for the annual runoff, and 1966–2003 and 2004–2013 were respectively identified as base and impacted periods. The results of elasticity coefficients showed that the runoff depth was most sensitive to the change of precipitation during the two periods. The relative contributions of precipitation, potential evapotranspiration and parameter n to runoff changes were 99.7%, −6.08% and 3.88%, respectively. Furthermore, the coupled contribution rate of other factors was less than 2.5%. Generally, results indicated that precipitation is the main factor on the historical runoff changes in this basin.
A Qualitative Study of Child Nutrition and Oral Health in El Salvador
Authors: Achalu Priyanka , Zahid Neha , Sherry Dominique N , Chang Andrew , Sokal-Gutierrez Karen
Published: July 2019

The nutrition transition from traditional diets to processed snacks and sugary beverages has contributed to a higher burden of child malnutrition, obesity, and tooth decay. While child health interventions typically promote nutritious eating, they rarely promote oral health. Mothers’ motivations for child nutrition and oral health practices need to be better understood. A convenience sample of 102 mothers in eight rural Salvadoran communities participated in focus groups addressing child nutrition and oral health. Focus groups were transcribed and coded using qualitative content analysis. Primary themes included generational changes in health environments; health knowledge, attitudes, and practices; and access and barriers to health services. Mothers noted general improvements in awareness of oral hygiene but poorer child oral health, which they attributed to widespread sales of unhealthy snacks and beverages near schools. Distance and cost limited families’ access to dental services. Knowledge gaps included the belief that oral iron supplements cause tooth decay, uncertainty regarding when to start tooth brushing, and until when parents should help children brush. Maternal-child health programs should emphasize the adverse health consequences of feeding young children processed snacks and sugary drinks, and promote dental care access and regulations to ensure health-promoting environments surrounding schools.
Characteristics of Pica Behavior among Mothers around Lake Victoria, Kenya: A Cross-Sectional Study
Authors: Chung Esther O. , Mattah Brian , Hickey Matthew D. , Salmen Charles R. , Milner Erin M. , Bukusi Elizabeth A. , Brashares Justin S. , Young Sera L. , Fernald Lia C.H. , Fiorella Kathryn J.
Published: July 2019

Background: Pica, the craving and purposeful consumption of nonfoods, is poorly understood. We described the prevalence of pica among women on Mfangano Island, Kenya, and examined sociodemographic and health correlates. Methods: Our cross-sectional study included 299 pregnant or postpartum women in 2012. We used a 24-h recall to assess pica, defined as consumption of earth (geophagy), charcoal/ash, or raw starches (amylophagy) and built multivariable logistic regression models to examine sociodemographic and health correlates of pica. Results: Eighty-one women (27.1%) engaged in pica in the previous 24 h, with 59.3% reporting amylophagy and 56.8% reporting geophagy, charcoal, and/or ash consumption. The most common substances consumed were raw cassava (n = 30, 36.6%), odowa, a chalky, soft rock-like earth (n = 21, 25.6%), and soil (n = 17, 20.7%). Geophagy, charcoal, and/or ash consumption was negatively associated with breastfeeding (OR = 0.38, 95% CI: 0.18–0.81), and amylophagy was associated with pregnancy (OR = 4.31, 95% CI: 1.24–14.96). Pica was more common within one of six study regions (OR = 3.64, 95% CI: 1.39–9.51). We found no evidence of an association between food insecurity and pica. Conclusion: Pica was a common behavior among women, and the prevalence underscores the need to uncover its dietary, environmental, and cultural etiologies.
Hydrogeochemical Characteristics and Water Quality Evaluation of Carboniferous Taiyuan Formation Limestone Water in Sulin Mining Area in Northern Anhui, China
Authors: Wang Meichen , Gui Herong , Hu Rongjie , Zhao Honghai , Li Jun , Yu Hao , Fang Hongxia
Published: July 2019

The Taiyuan formation limestone water in the Huaibei coalfield is not only the water source for coal mining, but also the water source for industry and agriculture in mining areas. Its hydrogeochemical characteristics and water quality are generally concerning. In this paper, conventional ion tests were carried out on the Taiyuan formation limestone water of 16 coal mines in the Sunan and Linhuan mining areas of the Huaibei coalfield. Piper trigram, Gibbs diagram and an ion scale coefficient map were used to analyze the hydrogeochemical characteristics of the Taiyuan formation limestone water. The water quality was evaluated in a fuzzy comprehensive manner. The results show that the main cation and anion contents in the Taiyuan formation limestone water were Na+ > Mg2+ > Ca2+ > K+, SO42− > HCO3− > Cl−. There were differences in the hydrogeochemical types of the Taiyuan formation limestone water in the two mining areas; HCO3-Na type water was dominant in the Sunan mining area and SO4·Cl-Na type water was dominant in the Linhuan mining area. The chemical composition of the Taiyuan formation limestone water is mainly affected by the weathering of the rock and is related to the dissolution of the evaporated salt and the weathering of the silicate. The fuzzy comprehensive evaluation results show that the V-type water accounts for a large proportion of the Taiyuan formation limestone water in the study area and the water quality is poor. This study provides a basis for the development and utilization of the Taiyuan formation limestone water and water environmental protection in the future.
Time Matters Differently in Leisure Experience for Men and Women: Leisure Dedication and Time Perspective
Authors: Codina Nuria , Pestana José V.
Published: July 2019

There are inequalities with respect to the amount of time men and women spend on leisure. Therefore, it can be assumed that these inequalities are also manifested in the experiences derived from leisure activities and in certain attitudes to life associated with the amount of time devoted to leisure, which emphasize time orientations towards the past, present and future. Based on these ideas, this study analyses the time spent on leisure activities, leisure experience (i.e., perceptions of freedom and satisfaction), and the five factors of the time perspective (hedonistic and fatalistic present; positive and negative past; and future orientation). Participants were 435 men and 434 women, ranging from 18 to 24 years (sample mean M = 21.14, standard deviation SD = 1.99). Two tools were used: a questionnaire about leisure experience, based on the time budget technique, and the Zimbardo Time Perspective Inventory. The results show significant gender differences: men have more leisure time, but women have a more positive leisure experience and time perspectives than men. It can be concluded that women enjoy themselves more with less available leisure time and are more positive with regard to time orientations.
Association of School Residential PM2.5 with Childhood High Blood Pressure: Results from an Observational Study in 6 Cities in China
Authors: Wang Xijie , Zou Zhiyong , Dong Bin , Dong Yanhui , Ma Yinghua , Gao Di , Yang Zhaogeng , Wu Shaowei , Ma Jun
Published: July 2019

Objective: To investigate the association of long-term PM2.5 exposure with blood pressure (BP) outcomes in children aged 6–18 years, and to examine the population attributable risk (PAR) of PM2.5 exposure. Methods: A total of 53,289 participants aged 6–18 years with full record of age, sex, BP, height, and local PM2.5 exposure from a cross-sectional survey conducted in 6 cities of China in 2013 were involved in the present study. PM2.5 data from 18 January 2013 to 31 December 2013 were obtained from the nearest environmental monitoring station for each selected school. Two-level linear and logistic regression models were used to evaluate the influence of PM2.5 on children’s BP, and PAR was calculated in each sex and age group. Results: Participants had a mean age of 10.8 (standard deviation: 3.4) years at enrollment, 51.7% of them were boys. U-shaped trends along with increased PM2.5 concentration were found for both systolic blood pressure (SBP) and diastolic blood pressure (DBP), with the thresholds of 57.8 and 65.0 μg/m3, respectively. Both increased annual mean of PM2.5 concentration and ratio of polluted days were associated with increased BP levels and high blood pressure (HBP), with effect estimates for BP ranging from 2.80 (95% CI: −0.51, 6.11) mmHg to 5.78 (95% CI: 2.32, 9.25) mmHg for SBP and from 0.77 (95% CI: −1.98, 3.52) mmHg to 2.66 (−0.35, 5.66) mmHg for DBP, and the odds ratios for HBP from 1.21 (0.43, 3.38) to 1.92 (0.65, 5.67) in the highest vs. the lowest quartiles. Overall, 1.16% of HBP in our participants could be attributed to increased annual mean of PM2.5 concentration, while 2.82% could be attributed to increased ratio of polluted days. These proportions increased with age. Conclusions: The association between long-term PM2.5 exposure and BP values appeared to be U-shaped in Chinese children aged 6–18 years, and increased PM2.5 exposure was associated with higher risk of HBP.
Implementation of a 2D Wavelet Method to Probe Mixed Layer Height Using Lidar Observations
Authors: Zhang Ning , Yang Fuyan , Chen Yan
Published: July 2019

A new method was developed to estimate mixed layer (ML) height with light detection and ranging (lidar) observations using a 2Dimensional (2D) wavelet method, which can consider the diurnal variation characteristics of ML height. Ideal signals and real lidar observations in Shanghai, China were used to evaluate the new method. The results showed that the new method is insensitive to the type of wavelet filters. The estimated ML heights obtained by the 2D wavelet method agreed well with both of the previous methods developed for the ML height probing using lidar, including the gradient method, the 1D-wavelet method, the standard deviation method, and the conventional radiosonde method. The primary differences among the results obtained via the different lidar methods occurred in the early morning or later afternoon; when the ML is well mixed, very small differences were observed among the different lidar methods. The new method showed better determination skills than other methods when compared to the radiosonde observation results. It also performed well when there were missing profiles or observation errors and it made the new method suitable for operations where data quality control may be missed.
Potential Application of Nitrogen-Doped Carbon Quantum Dots Synthesized by a Solvothermal Method for Detecting Silver Ions in Food Packaging
Authors: Lu Zifan , Su Tiantian , Feng Yanting , Jiang Shiqi , Zhou Chunxia , Hong Pengzhi , Sun Shengli , Li Chengyong
Published: July 2019

In this paper, nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by a solvothermal method using 1,2,4-triaminobenzene as a carbon precursor. The surface of the synthesized N-CQDs was modified with amino functional groups. The results indicated that N-CQDs had various N-related functional groups and chemical bonds and were amorphous in structure. At the same time, the quantum yield of N-CQDs was 5.11%, and the average lifetime of fluorescence decay was 5.79 ns. The synthesized N-CQDs showed good selectivity for and sensitivity to Ag+. A linear relationship between N-CQDs detection efficiency and Ag+ concentration was observed for concentration ranges of Ag+ corresponding to 0–10 μM and 10–30 μM. In addition, N-CQDs were used for the detection of trace Ag+ in food packaging material. The silver ion content of the sample determined by the N-CQDs detection method was 1.442 mg/L, with a relative error of 6.24% with respect to flame atomic absorption spectrometry, according to which the Ag+ content was 1.352 mg/L. This indicates that the N-CQDs detection method is reliable. Therefore, the N-CQDs prepared in this paper can detect Ag+ rapidly, simply, and sensitively and are expected to be a promising tool for the detection of trace Ag+ in food packaging materials.