bluuebunny/crossref_metadata_2025 huggingface dataset:
The correlation of sorption coefficients with nonlinearity of sorption isotherms in contaminated nearshore sediments in Bohai Bay (China)
Authors: Chen Hao , Zheng Binghui , Yang Wenqing
Published: March 2012

Phenanthrene sorption to seven nearshore sediments (Bohai Bay, China) collected under similar environments were investigated. Based upon well-fitted Freundlich models, the calculated organic carbon-normalized sorption coefficients at aqueous concentrations of 1 and 5,900 μg/L (PHE supercooled liquid solubility) showed positive and negative correlation with the nonlinearity of sorption isotherms, respectively, and the latter has not previously been reported. The present observations highlighted the viewpoint that PHE at low concentrations is primarily adsorbed to low quantity but highly adsorptive black carbon (BC) whereas partitioning to soft carbon may take over for high concentrations. Therefore, BC should be taken into account when modelling PHE (and analogues) sorption in contaminated sediments, and the correlation approach provides a promising diagnostic tool to this end.
A PCR-DGGE approach to evaluate the impact of wastewater source on the antibiotic resistance diversity in treated wastewater effluent
Authors: Sigala J. , Unc A.
Published: March 2012

Increased incidence of antibiotics in human-affected environments is raising concerns about increase in acquired antibiotic resistance by environmental bacteria. Wastewater collection and treatment systems are likely significant anthropogenic sinks and vectors for antibiotics and associated antibiotic resistance. Typical municipal treatment plants collect wastewaters of various sources, including well-established antibiotic resistance reservoirs such as hospitals, intensive care units and nursing homes, and integrate them with sources not commonly identified as major sources of antibiotic resistance, such as residential or industrial sources. A comprehensive PCR-DGGE diversity analysis of wastewater antibiotic-resistant bacteria was performed to evaluate the role of various wastewater sources in the discharge of antibiotic resistance by a municipal treatment plant. Wastewater sources are clearly inducing resistance in the final effluent but the role of each source type is highly variable, likely as a function of variable environmental conditions or water use patterns. Comparisons between primary treatment and secondary treatment stages indicate a strong role of the intensity of the wastewater treatment in the diversity profiles of antibiotic-resistant bacteria. While pervasiveness of antibiotic resistance in the system impedes clear discrimination between sources in the tested system, there are indications of specific source type related impacts.
Hydroponic system for the treatment of anaerobic liquid
Authors: Krishnasamy K. , Nair J. , Bäuml B.
Published: March 2012

The effluent from anaerobic digestion process has high concentrations of nutrients, particularly nitrogen, essential for plant growth but is not suitable for direct disposal or application due to high chemical oxygen demand (COD), low dissolved oxygen (DO), odour issues and is potentially phytotoxic. This research explored the optimum conditions of anaerobic effluent for application and dilutions of the effluent required to obtain better plant growth. A small-scale hydroponic system was constructed in a glasshouse to test different concentrations of anaerobic effluent against a commercial hydroponic medium as the control for the growth of silverbeet. It was found that the survival of silverbeet was negatively affected at 50% concentration due to low DO and NH4 toxicity. The concentration of 20% anaerobic liquid was found to be the most efficient with highest foliage yield and plant growth. The hydroponic system with 20% concentrated effluent had better utilisation of nutrients for plant growth and a COD reduction of 95% was achieved during the 50-day growth period. This preliminary evaluation revealed that the growth and development of silverbeet was significantly lower in anaerobic effluent compared with a commercial hydroponic plant growth solution. The nutrient quality of anaerobic effluent could be highly variable with the process and the waste material used and dilution may depend on the nutrient content of the effluent. It is recommended that, a pre-treatment of the effluent to increase DO and reduce ammonium content is required before plant application, and simple dilution by itself is not suitable for optimum plant growth in a hydroponic system.
Removal of organic impurities in waste glycerol from biodiesel production process through the acidification and coagulation processes
Authors: Xie Qiao-guang , Taweepreda Wirach , Musikavong Charongpun , Suksaroj Chaisri
Published: March 2012

Treatment of waste glycerol, a by-product of the biodiesel production process, can reduce water pollution and bring significant economic benefits for biodiesel facilities. In the present study, hydrochloric acid (HCl) was used as acidification to convert soaps into salts and free fatty acids which were recovered after treatment. The pH value, dosages of polyaluminum chloride (PACl) and dosage of polyacrylamide (PAM) were considered to be the factors that can influence coagulation efficiency. The pH value of waste glycerol was adjusted to a pH range of 3–9. The PACl and PAM added were in the range of 1–6 g/L and 0.005–0.07 g/L. The results showed best coagulation efficiency occurs at pH 4 when dosage of PACl and PAM were 2 and 0.01 g/L. The removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS) and soaps were 80, 68, 97 and 100%, respectively. The compositions of organic matters in the treated waste glycerol were glycerol (288 g/L), methanol (3.8 g/L), and other impurities (0.3 g/L).
Online estimation of VFA, alkalinity and bicarbonate concentrations by electrical conductivity measurement during anaerobic fermentation
Authors: Aceves-Lara Cesar-Arturo , Latrille Eric , Conte T. , Steyer Jean-Philippe
Published: March 2012

This paper describes the use of electrical conductivity for measurement of volatile fatty acids (VFA), alkalinity and bicarbonate concentrations, during the anaerobic fermentation process. Two anaerobic continuous processes were studied: the first was a laboratory reactor for hydrogen production from molasses and the second was a pilot process for anaerobic digestion (AD) of vinasses producing methane. In the hydrogen production process, the total VFA concentration, but not bicarbonate concentration, was well estimated from the on-line electrical conductivity measurements with a simple linear regression model. In the methane production process, the bicarbonate concentration and the VFA concentration were well estimated from the simultaneous on-line measurements of pH and electrical conductivity by means of non-linear regression with neural network models. Moreover, the total alkalinity concentration was well estimated from electrical conductivity measurements with a simple linear regression model. This demonstrates the use of electrical conductivity for monitoring the AD processes.
Methane and hydrogen sulfide emissions in UASB reactors treating domestic wastewater
Authors: Souza C. L. , Chernicharo C. A. L. , Melo G. C. B.
Published: March 2012

The release of CH4 and H2S in UASB reactors was evaluated with the aim to quantify the emissions from the liquid surfaces (three-phase separator and settler compartment) and also from the reactor's discharge hydraulic structures. The studies were carried out in two pilot- (360 L) and one demo-scale (14 m3) UASB reactors treating domestic wastewater. As expected, the release rates were much higher across the gas/liquid interfaces of the three-phase separators (5.4–9.7 kg CH4 m−2 d−1 and 23.0–35.8 g S m−2 d−1) as compared with the quiescent settler surfaces (11.0–17.8 g CH4 m−2 d−1 and 0.21 to 0.37 g S m−2 d−1). The decrease of dissolved methane and dissolved hydrogen sulfide was very large in the discharging hydraulic structures very close to the reactor (>60 and >80%, respectively), largely due to the loss to the atmosphere, indicating that the concentration of these compounds will probably fall to values close to zero in the near downstream structures. The emission factors due to the release of dissolved methane in the discharge structure amounted to around 0.040 g CH4 g CODinfl−1 and 0.060 g CH4 g CODrem−1, representing around 60% of the methane collected in the three-phase separator.
A calibration protocol of a one-dimensional moving bed bioreactor (MBBR) dynamic model for nitrogen removal
Authors: Barry U. , Choubert J.-M. , Canler J.-P. , Héduit A. , Robin L. , Lessard P.
Published: March 2012

This work suggests a procedure to correctly calibrate the parameters of a one-dimensional MBBR dynamic model in nitrification treatment. The study deals with the MBBR configuration with two reactors in series, one for carbon treatment and the other for nitrogen treatment. Because of the influence of the first reactor on the second one, the approach needs a specific calibration strategy. Firstly, a comparison between measured values and simulated ones obtained with default parameters has been carried out. Simulated values of filtered COD, NH4-N and dissolved oxygen are underestimated and nitrates are overestimated compared with observed data. Thus, nitrifying rate and oxygen transfer into the biofilm are overvalued. Secondly, a sensitivity analysis was carried out for parameters and for COD fractionation. It revealed three classes of sensitive parameters: physical, diffusional and kinetic. Then a calibration protocol of the MBBR dynamic model was proposed. It was successfully tested on data recorded at a pilot-scale plant and a calibrated set of values was obtained for four parameters: the maximum biofilm thickness, the detachment rate, the maximum autotrophic growth rate and the oxygen transfer rate.
Occurrence and fate of relevant substances in wastewater treatment plants regarding Water Framework Directive and future legislations
Authors: Martin Ruel S. , Choubert J.-M. , Budzinski H. , Miège C. , Esperanza M. , Coquery M.
Published: March 2012

The next challenge of wastewater treatment is to reliably remove micropollutants at the microgram per litre range. During the present work more than 100 substances were analysed through on-site mass balances over 19 municipal wastewater treatment lines. The most relevant substances according to their occurrence in raw wastewater, in treated wastewater and in sludge were identified, and their fate in wastewater treatment processes was assessed. About half of priority substances of WFD were found at concentrations higher than 0.1 μg/L in wastewater. For 26 substances, potential non-compliance with Environmental Quality Standard of Water Framework Directive has been identified in treated wastewater, depending on river flow. Main concerns are for Cd, DEHP, diuron, alkylphenols, and chloroform. Emerging substances of particular concern are by-products, organic chemicals (e.g. triclosan, benzothiazole) and pharmaceuticals (e.g. ketoprofen, diclofenac, sulfamethoxazole, carbamazepine). About 80% of the load of micropollutants was removed by conventional activated sludge plants, but about two-thirds of removed substances were mainly transferred to sludge.
GIS-based applications of sensitivity analysis for sewer models
Authors: Mair M. , Sitzenfrei R. , Kleidorfer M. , Möderl M. , Rauch W.
Published: March 2012

Sensitivity analysis (SA) evaluates the impact of changes in model parameters on model predictions. Such an analysis is commonly used when developing or applying environmental models to improve the understanding of underlying system behaviours and the impact and interactions of model parameters. The novelty of this paper is a geo-referenced visualization of sensitivity indices for model parameters in a combined sewer model using geographic information system (GIS) software. The result is a collection of maps for each analysis, where sensitivity indices (calculated for model parameters of interest) are illustrated according to a predefined symbology. In this paper, four types of maps (an uncertainty map, calibration map, vulnerability map, and design map) are created for an example case study. This article highlights the advantages and limitations of GIS-based SA of sewer models. The conclusion shows that for all analyzed applications, GIS-based SA is useful for analyzing, discussing and interpreting the model parameter sensitivity and its spatial dimension. The method can lead to a comprehensive view of the sewer system.
Denitrification with corncob as carbon source and biofilm carriers
Authors: Li Guochao , Chen Jie , Yang Tao , Sun Jianqi , Yu Shenglu
Published: March 2012

In this research the agricultural by-product corncob was investigated as a carbon source as well as a biofilm carrier to remove organic matter, expressed as chemical oxygen demand (COD) and nitrate nitrogen (nitrate-N), from wastewater in a batch laboratory reactor. The performance of a reactor with corncob as the carbon source and the biofilm carrier was compared with a control batch reactor with suspended plastic carriers and glucose as the sole carbon source. With 60 vol% of corncob carriers inside the reactor, a soluble COD/N ratio of 4.2 g COD g N−1 was enough for total denitrification, nearly half of the control reactor (9.5 g COD g N−1), at 23 h reaction time. The specific denitrification rate decreased with increasing soluble COD consumption for both reactors. Nitrate and COD removal efficiencies decreased with shorter retention times, with accentuated effects in the reactor. This study suggested corncob as a feasible carbon source and that reaction time was a limiting factor with corncob used as the carbon source for denitrification.
Labor and Pollution Prevention in Canada
Authors: Bennett Dave
Published: March 2012

This article gives an account of Canadian Chemicals Policy over the past three decades, including the project for the “virtual elimination” of toxic chemicals and the federal government's Chemical Management Plan. The latter is what remained when the virtual elimination program achieved few results. The article then embarks on its central theme: explaining how the labor movement introduced the concept and the practice of Pollution Prevention (P2) to Canada, as well as its impact on legislation and policies over the use reduction of chemical pesticides. The Appendix is a glossary of terms and concepts used in the article.
Living Arrangements and Risk for Late Life Depression: A Meta-Analysis of Published Literature
Authors: Xiu-Ying Hu , Qian Cheng , Xiao-Dong Peng , Xue-Mei Zhang , Chang-Quan Huang
Published: March 2012

Objective:

The goal of this study was to determine the relationship between living arrangements and risk for depression among older people.

Method:

MEDLINE, EMBASE, The Cochrane Library database was used to identify potential studies. The studies were divided into cross-sectional and longitudinal subsets. Qualitative meta-analysis of the cross-sectional studies and longitudinal studies was performed, respectively. For prevalence and incidence rates of depression, odds ratio (OR) and relative risk (RR) were calculated, respectively.

Results:

The qualitative meta-analysis showed that older people living alone had a higher risk of depression than those not living alone (OR: 1.44; 95% confidence interval [95% CI]: 1.04–1.99); Relative risk (RR: 1.27, 95% CI: 0.89–1.80) and those living with families (OR: 2.59, 95% CI: 1.60–4.20). Older people living in a nursing home (OR: 2.90, 95% CI: 0.94–8.94; RR: 1.94, 95% CI: 1.18–3.20) or institutionalized setting (OR: 1.86, 95% CI: 1.37–2.52; RR: 2.03, 95% CI: 1.12–3.70) had a higher risk of depression than those living in home.

Conclusions:

Despite the methodological limitations of this meta-analysis, living arrangements appear related to the risk for depression in the older population. Older persons living alone, in a nursing home, or in an institutionalized setting have higher risk for depression.
Solvent-free preparation of polylactic acid fibers by melt electrospinning using umbrella-like spray head and alleviation of problematic thermal degradation
Authors: Liu Yong , Zhao Fengwen , Zhang Chi , Zhang Jianming , Yang Weimin
Published: March 2012

Melt electrospinning is an even simpler and safer method compared with the
solution electrospinning in the production of ultra-fine fibers. Polylactic
acid (PLA) is a biodegradable and resorbable aliphatic ester that has
received significant attention in recent years. PLA is easily degradable at
high temperature in the process of melt electrospinning. High efficient
fibers were made using our designed umbrella-like spray head spinning
facility in this work. To find how to alleviate the problematic degradation
and what factors could be relevant to degradation, temperature, relative
molecular mass, Differential Scanning Calorimeter and X-ray Diffraction
patterns before and after spinning were investigated and compared with each
other. Results showed that fibers were facile shorten and fractured when spun
at 245?C while the relative molecular mass of PLA fibers decreased markedly
as compared with that spun at 210?C. To hinder the degradation, couple of
experimental efforts were implemented with adding antioxidants, raising
spinning voltage, lowering temperature, and reducing residence time. After
such efforts, it was observed that the relative molecular mass of the PLA
fibers was higher than those without inputting any efforts. The effect of
antioxidant 1010 was found the most promising on the alleviation of PLA
problematic thermal degradation.
Preventing β-Cell Loss and Diabetes With Calcium Channel Blockers
Authors: Xu Guanlan , Chen Junqin , Jing Gu , Shalev Anath
Published: March 2012

Although loss of functional β-cell mass is a hallmark of diabetes, no treatment approaches that halt this process are currently available. We recently identified thioredoxin-interacting protein (TXNIP) as an attractive target in this regard. Glucose and diabetes upregulate β-cell TXNIP expression, and TXNIP overexpression induces β-cell apoptosis. In contrast, genetic ablation of TXNIP promotes endogenous β-cell survival and prevents streptozotocin (STZ)- and obesity-induced diabetes. Finding an oral medication that could inhibit β-cell TXNIP expression would therefore represent a major breakthrough. We were surprised to discover that calcium channel blockers inhibited TXNIP expression in INS-1 cells and human islets and that orally administered verapamil reduced TXNIP expression and β-cell apoptosis, enhanced endogenous insulin levels, and rescued mice from STZ-induced diabetes. Verapamil also promoted β-cell survival and improved glucose homeostasis and insulin sensitivity in BTBR ob/ob mice. Our data further suggest that this verapamil-mediated TXNIP repression is conferred by reduction of intracellular calcium, inhibition of calcineurin signaling, and nuclear exclusion and decreased binding of carbohydrate response element–binding protein to the E-box repeat in the TXNIP promoter. Thus, for the first time, we have identified an oral medication that can inhibit proapoptotic β-cell TXNIP expression, enhance β-cell survival and function, and prevent and even improve overt diabetes.
The 10-Year Cost-Effectiveness of Lifestyle Intervention or Metformin for Diabetes Prevention
Authors:   The Diabetes Prevention Program Research Group
Published: March 2012

OBJECTIVE

The Diabetes Prevention Program (DPP) and its Outcomes Study (DPPOS) demonstrated that either intensive lifestyle intervention or metformin could prevent type 2 diabetes in high-risk adults for at least 10 years after randomization. We report the 10-year within-trial cost-effectiveness of the interventions.

RESEARCH DESIGN AND METHODS

Data on resource utilization, cost, and quality of life were collected prospectively. Economic analyses were performed from health system and societal perspectives.

RESULTS

Over 10 years, the cumulative, undiscounted per capita direct medical costs of the interventions, as implemented during the DPP, were greater for lifestyle ($4,572) than metformin ($2,281) or placebo ($752). The cumulative direct medical costs of care outside the DPP/DPPOS were least for lifestyle ($26,810 lifestyle vs. $27,384 metformin vs. $29,007 placebo). The cumulative, combined total direct medical costs were greatest for lifestyle and least for metformin ($31,382 lifestyle vs. $29,665 metformin vs. $29,759 placebo). The cumulative quality-adjusted life-years (QALYs) accrued over 10 years were greater for lifestyle (6.89) than metformin (6.79) or placebo (6.74). When costs and outcomes were discounted at 3% and adjusted for survival, lifestyle cost $12,878 per QALY, and metformin had slightly lower costs and nearly the same QALYs as placebo.

CONCLUSIONS

Over 10 years, from a payer perspective, lifestyle was cost-effective and metformin was marginally cost-saving compared with placebo. Investment in lifestyle and metformin interventions for diabetes prevention in high-risk adults provides good value for the money spent.
Fish Consumption, Dietary Long-Chain n-3 Fatty Acids, and Risk of Type 2 Diabetes
Authors: Wallin Alice , Di Giuseppe Daniela , Orsini Nicola , Patel Pinal S. , Forouhi Nita G. , Wolk Alicja
Published: March 2012

OBJECTIVE

The evidence on the association between fish consumption, dietary long-chain n-3 fatty acids, and risk of type 2 diabetes is inconsistent. We therefore performed a systematic review and meta-analysis of the available prospective evidence.

RESEARCH DESIGN AND METHODS

Studies were identified by searching the PubMed and EMBASE databases through 15 December 2011 and by reviewing the reference lists of retrieved articles. Prospective studies were included if they reported relative risk (RR) estimates with 95% CIs for the association between fish consumption and/or dietary long-chain n-3 fatty acids and incidence of type 2 diabetes. A dose-response random-effects model was used to combine study-specific RRs. Potential sources of heterogeneity were explored by prespecified stratifications.

RESULTS

Sixteen studies involving 527,441 participants and 24,082 diabetes cases were included. Considerable statistical heterogeneity in the overall summary estimates was partly explained by geographical differences. For each serving per week increment in fish consumption, the RRs (95% CIs) of type 2 diabetes were 1.05 (1.02–1.09), 1.03 (0.96–1.11), and 0.98 (0.97–1.00) combining U.S., European, and Asian/Australian studies, respectively. For each 0.30 g per day increment in long-chain n-3 fatty acids, the corresponding summary estimates were 1.17 (1.09–1.26), 0.98 (0.70–1.37), and 0.90 (0.82–0.98).

CONCLUSIONS

Results from this meta-analysis indicate differences between geographical regions in observed associations of fish consumption and dietary intake of long-chain n-3 fatty acids with risk of type 2 diabetes. In consideration of the heterogeneous results, the relationship warrants further investigation. Meanwhile, current public health recommendations on fish consumption should be upheld unchanged.
Fish Consumption and Incidence of Diabetes
Authors: Xun Pengcheng , He Ka
Published: March 2012

OBJECTIVE

—Ecological data suggest an inverse correlation between fish consumption and diabetes prevalence. However, epidemiological data on fish intake and diabetes incidence are controversial and inconclusive. Therefore, we aimed to assess the literature and determine the association between fish consumption and diabetes risk quantitatively.

RESEARCH DESIGN AND METHODS

—Prospective cohort studies published through August 2011 in peer-reviewed journals indexed in PubMed were selected. Additional information was retrieved through Google or a hand search of the references from relevant articles. The weighted relative risk (RR) and corresponding 95% CI for incident diabetes was estimated using random-effects models.

RESULTS

—A database was derived from nine eligible studies (12 independent cohorts), including 438,214 individuals with an average 11.4-year follow-up. Compared with those who never consumed fish or ate fish less than once per month, the pooled RR of incident diabetes was 0.99 (95% CI 0.85–1.16) for individuals who ate fish five or more times per week (Ptrend = 0.80). Similar results were found for long-chain n-3 polyunsaturated fatty acid intake. Study location was an effect modifier. An inverse association between fish intake and diabetes incidence was found by combining studies conducted in Eastern but not Western countries.

CONCLUSIONS

—Accumulated evidence generated from this meta-analysis does not support an overall inverse association of fish or fish oil intake with incidence of diabetes. The null association was modified by study location (Eastern vs. Western countries), which may reflect the possible difference between Eastern and Western dietary patterns. Further studies are warranted.
Comprehensive two-dimensional liquid chromatography — practical impacts of theoretical considerations. A review
Authors: Jandera Pavel
Published: March 2012

A theory of comprehensive two-dimensional separations by liquid chromatographic techniques is overviewed. It includes heart-cutting and comprehensive two-dimensional separation modes, with attention to basic concepts of two-dimensional separations: resolution, peak capacity, efficiency, orthogonality and selectivity. Particular attention is paid to the effects of sample structure on the retention and advantages of a multi-dimensional HPLC for separation of complex samples according to structural correlations. Optimization of 2D separation systems, including correct selection of columns, flow-rate, fraction volumes and mobile phase, is discussed. Benefits of simultaneous programmed elution in both dimensions of LCxLC comprehensive separations are shown.

Experimental setup, modulation of the fraction collection and transfer from the first to the second dimension, compatibility of mobile phases in comprehensive LCxLC, 2D asymmetry and shifts in retention under changing second-dimension elution conditions, are addressed. Illustrative practical examples of comprehensive LCxLC separations are shown.
Tachyonic field theory and neutrino mass running
Authors: Jentschura Ulrich
Published: March 2012

In this paper three things are done. (i) We investigate the analogues of Cerenkov radiation for the decay of a superluminal neutrino and calculate the Cerenkov angles for the emission of a photon through a W loop, and for a collinear electron-positron pair, assuming the tachyonic dispersion relation for the superluminal neutrino. The decay rate of a freely propagating neutrino is found to depend on the shape of the assumed dispersion relation, and is found to decrease with decreasing tachyonic mass of the neutrino. (ii)We discuss a few properties of the tachyonic Dirac equation (symmetries and plane-wave solutions), which may be relevant for the description of superluminal neutrinos seen by the OPERA experiment, and discuss the calculation of the tachyonic propagator. (iii) In the absence of a commonly accepted tachyonic field theory, and in view of an apparent “running” of the observed neutrino mass with the energy, we write down a model Lagrangian, which describes a Yukawa-type interaction of a neutrino coupling to a scalar background field via a scalar-minus-pseudoscalar interaction. This constitutes an extension of the standard model. If the interaction is strong, then it leads to a substantial renormalization-group “running” of the neutrino mass and could potentially explain the experimental observations.
Sensor network scheduling for identification of spatially distributed processes
Authors: Uciński Dariusz
Published: March 2012

Sensor network scheduling for identification of spatially distributed processes

The work treats the problem of fault detection for processes described by partial differential equations as that of maximizing the power of a parametric hypothesis test which checks whether or not system parameters have nominal values. A simple node activation strategy is discussed for the design of a sensor network deployed in a spatial domain that is supposed to be used while detecting changes in the underlying parameters which govern the process evolution. The setting considered relates to a situation where from among a finite set of potential sensor locations only a subset of them can be selected because of the cost constraints. As a suitable performance measure, theDs-optimality criterion defined on the Fisher information matrix for the estimated parameters is applied. The problem is then formulated as the determination of the density of gauged sites so as to maximize the adopted design criterion, subject to inequality constraints incorporating a maximum allowable sensor density in a given spatial domain. The search for the optimal solution is performed using a simplicial decomposition algorithm. The use of the proposed approach is illustrated by a numerical example involving sensor selection for a two-dimensional diffusion process.
Test signal generation for service diagnosis based on local structural properties
Authors: Ungermann Michael , Lunze Jan , Schwarzmann Dieter
Published: March 2012

Test signal generation for service diagnosis based on local structural properties

The paper presents a new approach to the generation of test signals used in service diagnosis. The tests make it possible to isolate faults, which are isolable only if the system is brought into specific operating points. The basis for the test signal selection is a structure graph that represents the couplings among the external and internal signals of the system and the fault signals. Graph-theoretic methods are used to identify edges that disappear under certain operating conditions and prevent a fault from changing the system behavior at this operating point. These operating conditions are identified by validuals, which are indicators obtained during the graph-theoretic analysis. The test generation method is illustrated by a process engineering example.
Fault-tolerant control strategy for actuator faults using LPV techniques: Application to a two degree of freedom helicopter
Authors: de Oca Saúl , Puig Vicenç , Witczak Marcin , Dziekan Łukasz
Published: March 2012

Fault-tolerant control strategy for actuator faults using LPV techniques: Application to a two degree of freedom helicopter

In this paper, a Fault Tolerant Control (FTC) strategy for Linear Parameter Varying (LPV) systems that can be used in the case of actuator faults is proposed. The idea of this FTC method is to adapt the faulty plant instead of adapting the controller to the faulty plant. This approach can be seen as a kind of virtual actuator. An integrated FTC design procedure for the fault identification and fault-tolerant control schemes using LPV techniques is provided as well. Fault identification is based on the use of an Unknown Input Observer (UIO). The FTC controller is implemented as a state feedback controller and designed using polytopic LPV techniques and Linear Matrix Inequality (LMI) regions in such a way as to guarantee the closed-loop behavior in terms of several LMI constraints. To assess the performance of the proposed approach, a two degree of freedom helicopter is used.
Nonlinear actuator fault estimation observer: An inverse system approach via a T-S fuzzy model
Authors: Xu Dezhi , Jiang Bin , Shi Peng
Published: March 2012

Nonlinear actuator fault estimation observer: An inverse system approach via a T-S fuzzy model

Based on a Takagi-Sugeno (T-S) fuzzy model and an inverse system method, this paper deals with the problem of actuator fault estimation for a class of nonlinear dynamic systems. Two different estimation strategies are developed. Firstly, T-S fuzzy models are used to describe nonlinear dynamic systems with an actuator fault. Then, a robust sliding mode observer is designed based on a T-S fuzzy model, and an inverse system method is used to estimate the actuator fault. Next, the second fault estimation strategy is developed. Compared with some existing techniques, such as adaptive and sliding mode methods, the one presented in this paper is easier to be implemented in practice. Finally, two numerical examples are given to demonstrate the efficiency of the proposed techniques.
A PRELIMINARY REPORT OF EXCAVATIONS IN FEWET, LIBYAN SAHARA
Authors: Castelli Roberto , Cremaschi Mauro , Gatto Maria Carmela , Liverani Mario , Mori Lucia
Published: March 2012

In 1997, the .Joint Italian-Libyan Archaeological Mission in the Akakus and Messak (Libyan Sahara)., presently directed by Savino di Lernia, started a program of historical archaeology aimed at recovering remains of the Garamantian period, ca 800 BC to 350 AD. One of the selected sites is Fewet, a small but well nucleated oasis some 10 km SW of Ghat. After a first sounding in 2001, part of the settlement was excavated in 2002-2003, and the adjacent necropolis was surveyed in 2003. The excavated settlement is a rounded compound, with a perimeter wall of stones and mud bricks and a series of small dwelling units, with partition walls in mud bricks, around a central empty space and a communal well. One half of the compound is well preserved, with smashed pottery and remains of carbonized seeds and basketry on the sandy floors. The site is radiocarbon dated to the 2nd-1st centuries BC. The necropolis, including ca 1000 tumuli (but the survey is not yet complete) extends over the entire course of Garamantian history, about one millennium or more, and the typological development - from conical to drum-shaped tumuli - is confirmed by the associated pottery from Final Pastoral to Post-Garamantian times. The site of Fewet provides a good example of a small rural settlement at the SW border of the Garamantian kingdom, and the entire research project (geology and palaeo-environmental studies, archaeological excavation and survey) helps to figure out the life and the material culture in a small Saharan oasis of the proto-historical period.
Correction: Tedder, A. et al. Using chloroplast trnF pseudogenes for phylogeography in Arabidopsis lyrata. Diversity 2010, 2, 653-678
Authors: Tedder Andrew , Hoebe Peter N. , Willi Yvonne , Ansell Stephen W. , Mable Barbara K.
Published: March 2012

In the original version of our article [1], insufficient acknowledgement was given for the source of some of the DNA samples used. We apologize for the original error. To correct this oversight, Yvonne Willi has been added as an author, a recent paper by Willi, Y. et al. (2010) has been added, the acknowledgements have been altered to more appropriately recognize support and funding, and the sources of samples collected have been corrected in Table 1. [...]
Application of Solution NMR Spectroscopy to Study Protein Dynamics
Authors: Göbl Christoph , Tjandra Nico
Published: March 2012

Recent advances in spectroscopic methods allow the identification of minute fluctuations in a protein structure. These dynamic properties have been identified as keys to some biological processes. The consequences of this structural flexibility can be far‑reaching and they add a new dimension to the structure-function relationship of biomolecules. Nuclear Magnetic Resonance (NMR) spectroscopy allows the study of structure as well as dynamics of biomolecules in a very broad range of timescales at atomic level. A number of new NMR methods have been developed recently to allow the measurements of time scales and spatial fluctuations, which in turn provide the thermodynamics associated with the biological processes. Since NMR parameters reflect ensemble measurements, structural ensemble approaches in analyzing NMR data have also been developed. These new methods in some instances can even highlight previously hidden conformational features of the biomolecules. In this review we describe several solution NMR methods to study protein dynamics and discuss their impact on important biological processes.
Calculation of the Arc Velocity Along the Polluted Surface of Short Glass Plates Considering the Air Effect
Authors: Sima Wenxia , Guo Fusheng , Yang Qing , Yuan Tao
Published: March 2012

To investigate the microphysics mechanism and the factors that influence arc development along a polluted surface, the arc was considered as a plasma fluid. Based on the image method and the collision ionization theory, the electric field of the arc needed to maintain movement with different degrees of pollution was calculated. According to the force of the charged particle in an arc plasma stressed under an electric field, a calculation model of arc velocity, which is dependent on the electric field of the arc head that incorporated the effects of airflow around the electrode and air resistance is presented. An experiment was carried out to measure the arc velocity, which was then compared with the calculated value. The results of the experiment indicated that the lighter the pollution is, the larger the electric field of the arc head and arc velocity is; when the pollution is heavy, the effect of thermal buoyancy that hinders arc movement increases, which greatly reduces the arc velocity.
The Extinction of the Conulariids
Authors: Lucas Spencer G.
Published: March 2012

Conulariids are unusual extinct metazoans most often considered to be a group of scyphozoan cnidarians or close relatives. Generally, the temporal range of conulariid fossils is perceived to be late Precambrian or Cambrian to Triassic, though a supposed Cretaceous conulariid from Peru was published 46 years ago. A re-evaluation of this fossil indicates it is not a conulariid, but instead a pinnacean bivalve (Pinna sp.), confirming that the geologically youngest conulariids are of Late Triassic age. However, a review of the Triassic conulariid fossil record indicates it is very sparse, with only eight published records. It does not provide a reliable basis for analyzing the structure of conulariid extinction. Nevertheless, conulariid extinction still appears to have taken place very close to the end of the Triassic. The cause of conulariid extinction may have been the onset of the Mesozoic marine revolution, in which durivorous predators developed new mechanisms for preying on the epifaunal benthos, including the conulariids.
Hypertension Knowledge-Level Scale (HK-LS): A Study on Development, Validity and Reliability
Authors: Baliz Erkoc Sultan , Isikli Burhanettin , Metintas Selma , Kalyoncu Cemalettin
Published: March 2012

This study was conducted to develop a scale to measure knowledge about hypertension among Turkish adults. The Hypertension Knowledge-Level Scale (HK-LS) was generated based on content, face, and construct validity, internal consistency, test re-test reliability, and discriminative validity procedures. The final scale had 22 items with six sub-dimensions. The scale was applied to 457 individuals aged ≥18 years, and 414 of them were re-evaluated for test-retest reliability. The six sub-dimensions encompassed 60.3% of the total variance. Cronbach alpha coefficients were 0.82 for the entire scale and 0.92, 0.59, 0.67, 0.77, 0.72, and 0.76 for the sub-dimensions of definition, medical treatment, drug compliance, lifestyle, diet, and complications, respectively. The scale ensured internal consistency in reliability and construct validity, as well as stability over time. Significant relationships were found between knowledge score and age, gender, educational level, and history of hypertension of the participants. No correlation was found between knowledge score and working at an income-generating job. The present scale, developed to measure the knowledge level of hypertension among Turkish adults, was found to be valid and reliable.
Antinociceptive and Anti-Inflammatory Effects of Ethanol Extract from Vernonia polyanthes Leaves in Rodents
Authors: Dos Santos Temponi Vanessa , Da Silva Jucélia Barbosa , Alves Maria Silvana , Ribeiro Antônia , Pinho José de Jesus Ribeiro Gomes de , Yamamoto Célia Hitomi , Pinto Miriam Aparecida Oliveira , Del-Vechio-Vieira Glauciemar , De Sousa Orlando Vieira
Published: March 2012

The ethanol extract from Vernonia polyanthes leaves (EEVP) was investigated for antinociceptive and anti-inflammatory effects at the doses (p.o.) of 100, 200 and 400 mg/kg in animal models. The extract reduced the number of abdominal contortions by 16.75% and 31.44% at a dose of 200 and 400 mg/kg, respectively. The results obtained showed that EEVP exerted a significant antinociceptive effect in the two phases of formalin. The EEVP increased the reaction time on a hot plate at the doses of 100, 200 and 400 mg/kg after 90 min of treatment. The paw edema was reduced by EEVP at the doses of 100, 200 and 400 mg/kg after 4 h of application of carrageenan. Doses of 200 and 400 mg/kg, administered 4 h before the carrageenan injection, significantly reduced the exudate volume (29.25 and 45.74%, respectively) and leukocyte migration (18.19 and 27.95%, respectively). These results suggest that V. polyanthes can be an active source of substances with antinociceptive and anti-inflammatory activities.
Genetic Diversity of the Endemic and Medicinally Important Plant Rheum officinale as Revealed by Inter-Simpe Sequence Repeat (ISSR) Markers
Authors: Wang Xu-Mei , Hou Xiao-Qi , Zhang Yu-Qu , Yang Rui , Feng Shi-Fang , Li Yan , Ren Yi
Published: March 2012

Rheum officinale Baill., an important but endangered medicinal herb, is endemic to China. Inter-simple sequence repeat (ISSR) markers were employed to investigate the genetic diversity and differentiation of 12 populations of R. officinale. Thirteen selected primers yielded 189 bright and discernible bands, with an average of 14.54 per primer. The genetic diversity was low at the population level, but pretty high at the species level (H = 0.1008, I = 0.1505, PPB = 28.95% vs. H = 0.3341, I = 0.5000, PPB = 95.24%, respectively) by POPGENE analysis. Analysis of molecular variance (AMOVA) showed that the genetic variation was found mainly among populations (74.38%), in line with the limited gene ﬂow (Nm = 0.2766) among populations. Mantel test revealed a signiﬁcant correlation between genetic and geographic distances (r = 0.5381, P = 0.002), indicating the role of geographic isolation in shaping the present population genetic structure. Both Bayesian analysis and UPGMA cluster analysis demonstrated the similar results. Our results imply that the conservation efforts should aim to preserve all the extant populations of this endangered species, and cultivation is proposed in this study.
Ecological and Evolutionary Determinants of Bark Beetle —Fungus Symbioses
Authors: Six Diana L.
Published: March 2012

Ectosymbioses among bark beetles (Curculionidae, Scolytinae) and fungi (primarily ophiostomatoid Ascomycetes) are widespread and diverse. Associations range from mutualistic to commensal, and from facultative to obligate. Some fungi are highly specific and associated only with a single beetle species, while others can be associated with many. In addition, most of these symbioses are multipartite, with the host beetle associated with two or more consistent partners. Mycangia, structures of the beetle integument that function in fungal transport, have evolved numerous times in the Scolytinae. The evolution of such complex, specialized structures indicates a high degree of mutual dependence among the beetles and their fungal partners. Unfortunately, the processes that shaped current day beetle-fungus symbioses remain poorly understood. Phylogeny, the degree and type of dependence on partners, mode of transmission of symbionts (vertical vs. horizontal), effects of the abiotic environment, and interactions among symbionts themselves or with other members of the biotic community, all play important roles in determining the composition, fidelity, and longevity of associations between beetles and their fungal associates. In this review, I provide an overview of these associations and discuss how evolution and ecological processes acted in concert to shape these fascinating, complex symbioses.
Finite-Element Modeling of Viscoelastic Cells During High-Frequency Cyclic Strain
Authors: Milner Jaques S. , Grol Matthew W. , Beaucage Kim L. , Dixon S. Jeffrey , Holdsworth David W.
Published: March 2012

Mechanotransduction refers to the mechanisms by which cells sense and respond to local loads and forces. The process of mechanotransduction plays an important role both in maintaining tissue viability and in remodeling to repair damage; moreover, it may be involved in the initiation and progression of diseases such as osteoarthritis and osteoporosis. An understanding of the mechanisms by which cells respond to surrounding tissue matrices or artificial biomaterials is crucial in regenerative medicine and in influencing cellular differentiation. Recent studies have shown that some cells may be most sensitive to low-amplitude, high-frequency (i.e., 1–100 Hz) mechanical stimulation. Advances in finite-element modeling have made it possible to simulate high-frequency mechanical loading of cells. We have developed a viscoelastic finite-element model of an osteoblastic cell (including cytoskeletal actin stress fibers), attached to an elastomeric membrane undergoing cyclic isotropic radial strain with a peak value of 1,000 µstrain. The results indicate that cells experience significant stress and strain amplification when undergoing high-frequency strain, with peak values of cytoplasmic strain five times higher at 45 Hz than at 1 Hz, and peak Von Mises stress in the nucleus increased by a factor of two. Focal stress and strain amplification in cells undergoing high-frequency mechanical stimulation may play an important role in mechanotransduction.
Novel Textile Scaffolds Generated by Flock Technology for Tissue Engineering of Bone and Cartilage
Authors: Walther Anja , Hoyer Birgit , Springer Armin , Mrozik Birgit , Hanke Thomas , Cherif Chokri , Pompe Wolfgang , Gelinsky Michael
Published: March 2012

Textile scaffolds can be found in a variety of application areas in regenerative medicine and tissue engineering. In the present study we used electrostatic flocking—a well-known textile technology—to produce scaffolds for tissue engineering of bone. Flock scaffolds stand out due to their unique structure: parallel arranged fibers that are aligned perpendicularly to a substrate, resulting in mechanically stable structures with a high porosity. In compression tests we demonstrated good mechanical properties of such scaffolds and in cell culture experiments we showed that flock scaffolds allow attachment and proliferation of human mesenchymal stem cells and support their osteogenic differentiation. These matrices represent promising scaffolds for tissue engineering.
Isolation and Structural Determination of the First 8-epi-type Tetrodotoxin Analogs from the Newt, Cynops ensicauda popei, and Comparison of Tetrodotoxin Analogs Profiles of This Newt and the Puffer Fish, Fugu poecilonotus
Authors: Kudo Yuta , Yasumoto Takeshi , Konoki Keiichi , Cho Yuko , Yotsu-Yamashita Mari
Published: March 2012

Identification of new tetrodotoxin (TTX) analogs from TTX-possessing animals might provide insight into its biosynthesis and metabolism. In this study, four new analogs, 8-epi-5,6,11-trideoxyTTX, 4,9-anhydro-8-epi-5,6,11-trideoxyTTX, 1-hydroxy-8-epi-5,6,11-trideoxyTTX, and 1-hydroxy-4,4a-anhydro-8-epi-5,6,11-trideoxyTTX, were isolated from the newt, Cynops ensicauda popei, and their structures were determined using spectroscopic methods. These are the first 8-epi-type analogs of TTX that have been found in a natural source. Furthermore, we examined the composition of the TTX analogs in this newt and in the ovary of the puffer fish, Fugu poecilonotus, using LC/MS. The results indicate that TTX and 11-deoxyTTX were present in both sources. However, 6-epiTTX and 8-epi-type analogs were detected only in the newt, while 5,6,11-trideoxyTTX was a specific and major analog in the puffer fish. Such considerable differences among analog compositions might reflect differences in the biosynthesis or metabolism of TTX between these animals.