bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Neuronal Apoptosis in Volumetric Change of Hippocampus in Diabetes Mellitus Type 1: A Predictive Model
Authors: Foghi Khadijeh , Ahmadpour Shahriar
Published: July 2013

Background. Neuronal apoptosis is the major cause of diabetes central neuropathy, but its role in volumetric changes of hippocampus has not been clarified. The aims of this study were to assess the role of apoptosis in volumetric changes of dentate gyrus (DG) and CA3 region of hippocampus and to determine a reference point in which these neuropathological changes reach a meaningful level. Methods and Materials. Diabetes was induced in male Wistar rats (N=10) by streptozotocin (60 mg/kg). Six weeks after diabetes, verification animals were divided into four groups as follows: diabetic treated with insulin (3–5 U), diabetic treated with vitamin C (80 mg/kg), and diabetic and control groups. At the end of 8 weeks, numerical density of apoptotic neurons and volume of dentate gyrus and CA3 were calculated by stereological methods. Results. The number of apoptotic neurons in DG and CA3 in diabetic group showed significant level of difference in comparison with the control (P<0.001). The volume of DG and CA3 in diabetic and vitamin C showed significant level of difference compared with control (P<0.001). Conclusion. Our results suggest that DG and CA3 volume reduction begins and progresses independently of neuronal loss.
Optimization of L-methionine Bioconversion to Aroma-active Methionol by Kluyveromyces lactis Using the Taguchi Method
Authors: Koh Matthew K. P. , Sun Jingcan , Liu Shao Quan
Published: July 2013

The bioproduction of methionol through fermentation was performed by Kluyveromyces lactis KL71 in coconut cream supplemented with L-methionine (Met). This bioprocess was successfully optimized with the Taguchi method applying the L27 (313) orthogonal array. Among these studied factors, shaking speed was found to be the most significant factor that affected the bioproduction of methionol, followed by incubation time, pH level and Met concentration. The optimum fermentation conditions were determined as follows: 0.45% (w/v) of Met, 48 h of incubation, shaking speed of 160 rpm, 0.05% (w/v) of yeast extract (YE), 0 mg/L of diammonium phosphate (DAP) and pH of 6.3. Under the optimum conditions, the signal to noise (S/N) ratio achieved was 59.9 decibels (dB), which was in good agreement with the predicted S/N ratio of 58.2 dB. The average yield of methionol obtained under the optimum fermentation conditions was 990.1 ± 49.7 µg/mL. This indicates that the Taguchi method was effective for the optimization of bioproduction of methionol by K. lactis.
High HIV‐1 prevalence, risk behaviours, and willingness to participate in HIV vaccine trials in fishing communities on Lake Victoria, Uganda
Authors: Kiwanuka Noah , Ssetaala Ali , Mpendo Juliet , Wambuzi Matthias , Nanvubya Annet , Sigirenda Simon , Nalutaaya Annet , Kato Paul , Nielsen Leslie , Kaleebu Pontiano , Nalusiba Josephine , Sewankambo Nelson K
Published: July 2013

Introduction

HIV epidemics in sub‐Saharan Africa are generalized, but high‐risk subgroups exist within these epidemics. A recent study among fisher‐folk communities (FFC) in Uganda showed high HIV prevalence (28.8%) and incidence (4.9/100 person‐years). However, those findings may not reflect population‐wide HIV rates in FFC since the study population was selected for high‐risk behaviour.

Methods

Between September 2011 and March 2013, we conducted a community‐based cohort study to determine the population representative HIV rates and willingness to participate (WTP) in hypothetical vaccine trials among FFC, Uganda. At baseline (September 2011–January 2012), a household enumeration census was done in eight fishing communities (one lakeshore and seven islands), after which a random sample of 2200 participants aged 18–49 years was selected from 5360 individuals. Interviewer‐administered questionnaire data were collected on HIV risk behaviours and WTP, and venous blood was collected for HIV testing using rapid HIV tests with enzyme‐linked immunosorbent assay (EIA) confirmation. Adjusted prevalence proportion ratios (adj.PPRs) of HIV prevalence were determined using log‐binomial regression models.

Results

Overall baseline HIV prevalence was 26.7% and was higher in women than men (32.6% vs. 20.8%, p<0.0001). Prevalence was lower among fishermen (22.4%) than housewives (32.1%), farmers (33.1%) and bar/lodge/restaurant workers (37%). The adj.PPR of HIV was higher among women than men (adj.PPR =1.50, 95%; 1.20, 1.87) and participants aged 30–39 years (adj.PPR=1.40, 95%; 1.10, 1.79) and 40–49 years (adj.PPR=1.41, 95%; 1.04, 1.92) compared to those aged 18–24 years. Other factors associated with HIV prevalence included low education, previous marriage, polygamous marriage, alcohol and marijuana use before sex. WTP in hypothetical vaccine trials was 89.3% and was higher in men than women (91.2% vs. 87.3%, p=0.004) and among island communities compared to lakeshore ones (90.4% vs. 85.8%, p=0.004).

Conclusions

The HIV prevalence in the general fisher‐folk population in Uganda is similar to that observed in the “high‐risk” fisher folk. FFC have very high levels of willingness to participate in future HIV vaccine trials.
Doppler Velocity Estimation Based on Spectral Characteristics of M-Sequence-Modulated Signals in Ultrasonic Measurement for Moving Objects
Authors: Hirata Shinnosuke , Hachiya Hiroyuki
Published: July 2013

Pulse compression using maximum-length sequence (M-sequence) can improve the signal-to-noise ratio (SNR) of the reflected echo and distance resolution in the pulse–echo method. In the case of a moving object, however, the echo is modulated due to the Doppler effect. The Doppler-shifted M-sequence-modulated signal cannot be correlated with the reference signal, which corresponds to the transmitted M-sequence-modulated signal. Therefore, Doppler velocity estimation before the correlation and cross correlation of the received signal with Doppler-shifted reference signals has been proposed. In this paper, the proposed Doppler velocity estimation based on spectral characteristics of cyclic M-sequence-modulated signals is described. Then, the Doppler velocity estimation is evaluated based on computer simulations. The Doppler velocity can be estimated from the Fourier-transformed spectral density of cycles of the M-sequence-modulated signal with high resolution even in noisy environments. According to the evaluation, furthermore, the cycle number and the number of carrier waves in 1 digit of the M-sequence-modulated signal should be decreased to improve the resolution and accuracy when the length of the transmitted signal is determined.
Proposal of Non Contact Inspection Method for Concrete Structures Using High-Power Directional Sound Source and Scanning Laser Doppler Vibrometer
Authors: Akamatsu Ryo , Sugimoto Tsuneyoshi , Utagawa Noriyuki , Katakura Kageyoshi
Published: July 2013

Maintenance for concrete structures such as buildings, bridges, and tunnels is necessary, because it is thought that a lot of them show deterioration. As a periodic inspection, a hammering test is the most popular method. However, it has several problems. One of the problems is that it is difficult to inspect the places where people cannot reach. Therefore, non contact inspection methods have been developed. As a non-contact inspection method, we propose a system consisting of a high-power directional sound source and a scanning laser doppler vibrometer (SLDV). In this method, an air-borne sound wave is used for the excitation of a concrete wall, and then the vibration velocities on the concrete wall are measured two-dimensionally by the SLDV. From the vibration velocity, defective parts can be detected. In this paper, we describe two types of experiment on the feasibility of our proposed method. In these experiments, concrete wall test pieces, which have artificial defects, are used. From the experimental results, we confirmed the effectiveness of our proposed method as a non contact inspection method for concrete structures.
Tunable Surface Acoustic Wave Filter Using Integrated Micro-Electro-Mechanical-System Based Varactors Made of Electroplated Gold
Authors: Konno Akira , Hirano Hideki , Inaba Masahiro , Hashimoto Ken-ya , Esashi Masayoshi , Tanaka Shuji
Published: July 2013

This paper describes the fabrication and preliminary evaluation of a 200 Ω terminated, 1 GHz tunable surface acoustic wave (SAW) filter with electrostatic micro-electro-mechanical-system (MEMS) varactors. The tunable filter was constructed on a 15° Y LiNbO3substrate to use Love wave with an electromechanical coupling coefficient as high as 25%. The bridge structure of the MEMS varactor was fabricated by Au electroplating on a sacrificial photoresist, which was finally removed by either O2plasma ashing or O3water etching. The measured center frequency was 1.07 GHz, and the bandwidth was 171 MHz, i.e., 16% in relative bandwidth. The MEMS varactor, which was connected to a series SAW resonator in parallel, pulled in by an actuation voltage of 150 V DC, and the right passband edge moved to lower frequency side by 15 MHz.
Trapping of Microparticles in Cylindrical Standing Wave Fields
Authors: Yang Jeongwon , Hwang Haerang , Bae Young Min , Kim Moojoon , Ha Kanglyeol
Published: July 2013

In this study, in order to determine the positions where microparticles are trapped in a cylindrical standing wave field, we derived equations giving the radiation force and potential energy distribution. Then, the trapped pattern and its variation with time in a hollow cylindrical transducer were simulated. The simulation results showed that polystyrene particles moved to and aggregated near positions corresponding to pressure nodes, which were estimated from the derived equations. These were confirmed by measurement. In addition, it was demonstrated that biological particles of the green algae chlorella show similar trapping phenomena to polystyrene particles.
Measurement of Diffraction Pattern Using Two-Dimensional Image Sensor for Obtaining Instantaneous Diameter Distribution of Acoustic Cavitation Bubbles
Authors: Kuroyama Takanobu , Mizutani Koichi , Wakatsuki Naoto , Ohbuchi Takeshi
Published: July 2013

To shorten the measurement time for the diameter distribution of acoustic cavitation by laser diffraction, a new measurement method for laser diffraction patterns using an image sensor was proposed. The laser diffraction pattern caused by the oscillating acoustic cavitation was measured using the charge-accumulation-type image sensor and the acousto optic modulator. The diameter distribution was calculated from the diffraction pattern by solving the least squares problem that minimizes the sum of squares of the difference between the theoretical and the measured diffraction patterns. The proposed method using the image sensor enables the measurement of diffraction patterns at 18 phases of ultrasound within 15 s, which corresponds to one-sixth of the measurement time of the present method using a scanning photodetector. The diffraction pattern at each phase was measured in 22 ms and the measured diffraction pattern corresponded to the instantaneous diffraction pattern ensemble-averaged 421 times. In addition, it was shown that the proposed method could reduce the effect of the speckle noise by the spatial averaging of the diffraction pattern. The residual of the least squares method was reduced from the previous method. As a result, it was concluded that the time required for measuring diffraction patterns could be reduced and the possibility of the instantaneous measurement of diameter distribution was suggested.
Experimental and Numerical Analysis of Temperature Rise in Phantom Caused by High-Intensity Focused Ultrasonic Irradiation
Authors: Tanaka Shin , Shimizu Kazuma , Sakuma Suguru , Tsuchiya Takenobu , Endoh Nobuyuki
Published: July 2013

For the safe usage of ultrasonic diagnosis, it is important to research the temperature rise in the human body caused by ultrasonic irradiation. The temperature increase in the human body has been estimated by numerical analysis and an experiment using a tissue-mimicking phantom. In this study, we developed a method for the three-dimensional nonlinear simulation of temperature rise caused by intense ultrasonic irradiation. The sound fields and thermal distributions were calculated by the nonlinear finite difference time domain (FDTD) method and heat conduction equation (HCE) method, respectively. The sound fields and waveforms in water were measured using a hydrophone. The thermal distributions caused by ultrasonic irradiation in the phantom were measured using a thermal camera. The simulation and experimental results of the sound field and thermal distribution were in good agreement. The maximum temperature increase caused by focused ultrasonic irradiation in the phantom was accurately estimated.
Experimental Study of Active Path Block in a Multi-Bifurcated Flow by Microbubble Aggregation
Authors: Shigehara Nobuhiko , Demachi Fumi , Koda Ren , Mochizuki Takashi , Masuda Kohji , Ikeda Seiichi , Arai Fumihito , Miyamoto Yoshitaka , Chiba Toshio
Published: July 2013

We previously reported our attempts at the active control of microbubble aggregations using acoustic radiation force, which propels microbubbles and adjusts the size of aggregations. However, because we used simple-shape artificial blood vessels, the behavior of aggregations in a small channel, e.g., the probability to obstruct the bloodstream, and the possibility of embolization, has not been predicted. Thus, we designed and fabricated a multi-bifurcated artificial blood vessel to apply to the production and active control of microbubble aggregations. Then, we introduced two kinds of ultrasound transducers for producing and propelling aggregations. First, we produced aggregations in a flow to measure their size and investigate their variation according to the emission duration of ultrasound. Then, we control the aggregations in an artificial blood vessel to verify their controllability. When ultrasound was stopped, the aggregations flaked off the vessel wall and flowed downstream, were propelled to the desired path, and finally were caught at a narrow path. We verified the same experiment under similar parameters to calculate the probability of realizing a path block. When the flow velocity was 20 mm/s, almost 50% of the aggregations were induced to flow through the desired path and a maximum probability of realizing a path block of 86% was achieved with the formation of aggregations.
Application of Ultrasonic Microscopy to Evaluation of Electrically Ligated Vessel Tissue
Authors: Yamaoka Terumasa , Yamaguchi Tadashi , Sekine Masashi , Zenbutsu Satoki , Matsubara Hisahiro , Hayashi Hideki
Published: July 2013

Electrothermal bipolar vessel sealing devices have been used for the ligation of vessels during surgical procedures. However, unexpected bleeding is still reported, the cause of which is not yet clarified by conventional histopathological analysis. In the present study, ultrasonic microscopy with a central frequency of 80 MHz was applied to evaluate the mechanical properties of ligated vessels. Five arteries and five veins were electrically sealed for 0, 2, 4, 6, and 8 s. The speed of sound in the native adventitia were higher than that in the media. The speed of sound was not correlated with sealing time. However, acoustical inhomogeneity was seen in the sealed vessels. Thus, the acoustical properties of vessels may be affected by the electrothermal effect, and the evaluation of mechanical properties is important for assessing the tissue sealing performance.
Shear Wave Imaging Using Phase Modulation Component of Harmonic Distortion in Continuous Shear Wave Excitation
Authors: Parajuli Raj Kumar , Tei Reisen , Nakai Daisuke , Yamakoshi Yoshiki
Published: July 2013

An elasticity imaging method using continuous shear wave excitation (CSWE) is expected to be a safe and quantitative technique. A velocity map could be produced by propagating wave number spectrum analysis of a two-dimensional (2D) displacement map of shear wave propagation. However; the problems of accuracy and resolution have limited the reliability of this technique in medical diagnosis. In this paper, we propose a shear wave imaging system for reconstructing the spatial phase modulation component of shear wave propagation in order to obtain high-resolution images of continuous shear wave excitation. Shear wave local velocity, which is derived from the spatial differentation of the phase of complex displacement, is adopted as an imaging parameter. A fine texture-like pattern of the phase modulation component appears in the local velocity map, which gives precise information of small-amplitude phase modulation.
Multipath Effects on High-Frequency Coherent Acoustic Communications in Shallow Water
Authors: Son Su-Uk , Kim Hyeonsu , Joo Jongmin , Choi Jee Woong
Published: July 2013

Shallow-water acoustic communication channel, referred to as a multipath-limited channel, produces inter-symbol interference that poses a significant obstacle to reliable communication. Accordingly, signal-to-multipath ratio (SMR), rather than signal-to-noise ratio (SNR), becomes an important factor affecting communication performance. However, it is difficult to estimate SMR from measured communication data, especially at higher frequency (>10 kHz) because many arrivals scattered from rough ocean boundaries produce a significant intrapath time spreading, which acts as random noise in communication. In this paper, the energy fraction of the channel impulse response existing in one symbol duration is proposed as a parameter for estimating the quality of shallow-water communication channels. This parameter is compared with the bit-error-rate performance for data acquired in shallow water off the south coast of Korea, where the water depth is 45 m and the bottom consists of sandy clay sediment. The results imply that the energy fraction in one symbol duration may be used as a parameter for describing shallow-water communication channels and applied to the quick decision of a symbol or bit rate in a shallow-water field for reliable underwater communication.
Influence of the Structure Parameters on the Relaxation of Semipolar InGaN/GaN Multi Quantum Wells
Authors: Keller Stacia , Farrell Robert M. , Iza Michael , Terao Yutaka , Young Nathan , Mishra Umesh K. , Nakamura Shuji , DenBaars Steven P. , Speck James S.
Published: July 2013

The influence of semipolar (202̄1) InGaN/GaN multi quantum well (MQW) structure parameters such as well composition and thickness (d
w), barrier thickness, as well as total number of periods on the structural and optical properties of the MQWs grown on (202̄1) GaN by metal organic chemical vapor deposition was investigated. At d
w < 3 nm, the MQW stacks were very robust with respect to changes in the barrier thickness or the number of periods in the MQW stack, and 30 period (2.5 nm In0.25Ga0.75N/8.5 nm GaN) MQWs exhibiting bright luminescence at 465 nm were demonstrated. For all samples with d
w<3 nm in this study, one-dimensional relaxation via misfit dislocations did not lead to any deterioration of the optical properties of the films, and a decrease in the photoluminescence intensity was only observed after the on-set of two-dimensional relaxation via non-basal plane defects.
High Power Efficiency AlGaN-Based Ultraviolet Light-Emitting Diodes
Authors: Passow Thorsten , Gutt Richard , Kunzer Michael , Pletschen Wilfried , Kirste Lutz , Forghani Kamran , Scholz Ferdinand , Köhler Klaus , Wagner Joachim
Published: July 2013

High-efficiency AlGaN-based 355 nm UV light-emitting diodes (LEDs) grown on low-dislocation-density AlGaN/sapphire templates with an output power of 9.8 mW (22.7 mW) at a DC current of 40 mA (100 mA) are reported. The corresponding maximum external quantum efficiency and maximum power efficiency are 7.2 and 6.5%, respectively. Based on a rate equation model, a method is presented to derive the extraction as well as the injection and internal quantum efficiency as a function of the driving current. The thus obtained injection and internal quantum efficiencies amount to 51 and 47% at 40 mA, the extraction efficiency to 29%.
Observation of Side-Gating Effect in AlGaN/GaN Heterostructure Field Effect Transistors
Authors: Ohno Yasuo , Kio Yusuke , Ikawa Yusuke , Ao Jin-Ping
Published: July 2013

The side-gating effect was demonstrated in AlGaN/GaN heterostructure field effect transistors (HFETs) for the first time. Using 10-µm-thick i-GaN buffer layers, drain currents decreased significantly with the application of a negative bias on a side gate 8 µm away from the FET. The transient responses with LED illumination demonstrated half-recovery condition that can be interpreted as a negative-charge redistribution through a hole emission from traps. The application of a positive side-gate bias confirmed the half-recovery mechanism. From the temperature variation measurements, the trap energy level is estimated to be 0.76 eV from the valence band with a hole capture cross section of approximately 4×10-16 cm2. All these results indicate that the side-gating effect is caused by hole traps in the i-GaN layer, which is in accord with the Shockley–Read–Hall model of deep traps.
Communication dynamics in twitter during political campaigns: The case of the 2011 Spanish national election
Authors: Aragón Pablo , Kappler Karolin Eva , Kaltenbrunner Andreas , Laniado David , Volkovich Yana
Published: July 2013

The irruption of social media in the political sphere is generating repositories of “Big Data,” which can be mined to gain insights into communication dynamics. The research reported here relies on a large data set from Twitter to examine the activity, emotional content, and interactions of political parties and politicians during the campaign for the Spanish national elections in November 2011. The aim of this study is to investigate the adaptation of political parties to this new communication and organizational paradigm originating in the evolution of the Internet and online social networks. We analyze the reply and retweet networks of seven political parties with significant offline differences to assess their conversation and information diffusion patterns. We observe that political parties, and especially the major traditional parties, still tend to use Twitter just as a one‐way flow communication tool. Moreover, we find evidence of a balkanization trend in the Spanish online political sphere, as observed in previous research for other countries.
Mapping the public agenda with topic modeling: The case of the Russian livejournal
Authors: Koltsova Olessia , Koltcov Sergei
Published: July 2013

This article describes agendas as “packages” of topics of varying salience, set by the Russian Internet users on Russia's leading blog platform LiveJournal. The research involved modeling LiveJournal's topic structure, viewed as an important component of what is termed here self‐generated public opinion. Topic modeling was performed automatically with the LDA algorithm, and complemented with hand labeling of topics. Data were collected by software created by the authors to generate a relational database storing all posts by the top 2,000 LiveJournal users from three one‐month periods: two during the Russian parliamentary and presidential elections 2011–2012, and one control period. We find that LiveJournal top users share their attention evenly between “social/political” and “private/recreational” issues, the proportion being very stable. However, the substitution of diverse public affairs issues by the topics related to national street protests in the politicized periods compared to the control period was found both automatically and manually. The group of topics centered around social issues demonstrates the biggest volatility in terms of its composition and may serve as the foundation for monitoring self‐generated public opinion by further application of sentiment/opinion mining methods to these topics.
Responsive Monochromatic Color Display Based on Nanovolcano Arrays
Authors: Ai Bin , Yu Ye , Möhwald Helmuth , Zhang Gang
Published: July 2013

Novel nanohole arrays with volcano‐shaped holes (truncated cones) are reported to obtain structural colors with excellent purity without using index‐matching layers. They further show efficient sensitive environment responses. The novel structures are fabricated via a low‐cost, large‐area colloidal lithography method. Numerical simulations demonstrate that each nanovolcano, comprising one upper hole and one lower hole, excites two surface plasmon resonances (SPRs), generating only one single transmission maximum at a tunable position (monochromatic color), and calculations show excellent agreement with the measured spectra. Three primary red–green–blue (RGB) monochromatic colors are obtained by adjusting the lattice constant. Moreover, the colors can be tuned easily and inexpensively across the whole visible range, retaining a single sharp transmission peak, showing an efficient responsive color display. Because of the simple fabrication process and remarkable properties, Ag nanovolcano arrays are believed to be greatly advantageous for sensors, optical devices, color displays, and nanoantennas. Furthermore, the novel structures can be used as versatile substrates for cell biology, analysis of single protein molecules, and surface‐enhanced Raman scattering.
Synthesis of Blended Fibers of Poly(3‐hydroxybutyric acid) and Poly(propylene carbonate) Scaffolds for Tissue Engineering
Authors: Nagiah Naveen , Ramanathan Giriprasath , Uma Tiruchirapalli Sivagnanam , Madhavi Lakshmi , R Anitha , Natarajan Tirupattur Srinivasan
Published: July 2013

Electrospinning is one of the cheapest and upscalable techniques to mimic the structure of the extracelluar matrix of tissues and organs. Fibers of submicron and nanoscale dimensions were obtained by electrospining blended polymer solutions of poly(3‐hydroxybutyric acid) and poly(propylene carbonate) using 1,1,1,3,3,3 hexafluoro‐2‐propanol and 2,2,2 trifluoroethanol as solvents. The resultant fibers were characterized using scanning electron microscopy, differential scanning calorimetry, and attenuated total reflection‐fourier transformed infrared spectroscopy. The fibrous scaffold had competent tensile properties and supported the growth and proliferation of human dermal fibroblasts and keratinocytes with normal morphology, thus proving its reliability in using it as a potential scaffold for skin regeneration. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21370; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21370
Exploration of the Bulk Atom Transfer Radical Polymerization of Styrene
Authors: Qu Jian‐Bo , Huan Guan‐Sheng , Chen Yan‐Li , Shao Hui‐Hui , Wang Li
Published: July 2013

The synthesis of well‐defined polystyrene by atom transfer radical polymerization (ATRP) is reported. The effects of temperature, initiators, catalysts, and ligands on styrene bulk ATRP were investigated in detail. Results indicated that the initiator activity for a given monomer needs careful matching to bring about a match of the chain‐initiation and chain‐propagation rates. The higher activity is not necessarily the better. Thus, the less reactive monomer, styrene, was efficiently initiated by 1‐phenylethyl bromide (1‐PEBr), which only has a moderate initiator activity. Similarly, the catalyst system had to be carefully matched to achieve a real controlled/living radical polymerization. Controlled/living bulk ATRP of styrene was achieved by using 1‐PEBr as initiator, copper(I) bromide as catalyst, and N,N,N′,N′′,N′′‐ pentamethyldiethyllenetriamine as ligand at 90°C. After 4 h, the monomer conversion reached 51.8%, the practical molecular weight of polystyrene coincided well with the theoretical molecular weight of polystyrene, and the molecular weight distribution was 1.15. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21371; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21371
Steady states for chemical process plants: A legacy code, time‐stepping approach
Authors: Kavouras Andreas , Georgakis Christos , Kelley C. T. , Siettos Constantinos , Kevrekidis Ioannis G.
Published: July 2013

Given a legacy dynamic simulator of a chemical process plant, we construct a computational procedure that can be “wrapped around” the simulator to compute its steady states (both stable and unstable) and their dependence on input parameters. We apply this approach to the Tennessee Eastman (TE) challenge problem presented by Downs and Vogel, who also provided a FORTRAN process model. Using the FORTRAN simulator as a black‐box input‐output map, we enable it to systematically converge to isolated solutions and study their stability and parametric dependence within the equation‐free framework. The presence of neutrally stable modes in TE problem (due to so‐called inventories), their interplay with the problem formulation and the convergence of the solution procedure is explored and rationalized. Interestingly, our time‐stepper formulation can automatically take advantage of separation of time scales, when present, to enhance computational convergence. The approach enables legacy dynamic simulators to calculate several dynamic problem characteristics useful for controller design and/or process optimization. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3308–3321, 2013
Note on flash and distillation systems
Authors: Aggarwal Mohit , Ydstie B. Erik
Published: July 2013

Flash and distillation systems evolving on the equilibrium manifold possess stable steady states when the molar flows and the boundary conditions are fixed and a vapor and liquid phase is present at all times. The results extend the range of validity of a local stability theorem for linear, constant molar overflow systems due to Acrivos and Amundson. The approach to stability analysis is motivated by the tangent plane method developed by Gibbs to open systems as it takes advantage of the negative curvature of the entropy surface to construct a Lyapunov function. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3322–3332, 2013
La0.6Sr0.4Co0.8Ga0.2O3‐δ (LSCG) hollow fiber membrane reactor: Partial oxidation of methane at medium temperature
Authors: Kathiraser Yasotha , Kawi Sibudjing
Published: July 2013

In this study, La0.6Sr0.4Co0.8Ga0.2O3‐δ (LSCG) hollow fiber membrane reactor was integrated with Ni/LaAlO3‐Al2O3 catalyst for the catalytic partial oxidation of methane (POM) reaction. The process was successfully carried out in the medium temperature range (600–800°C) for reaction of blank POM with bare membrane, catalytic POM reaction and swept with H2:CO gas mixture. For the catalytic POM reaction, enhancement in selectivity to H2 and CO is obtained between 650–750°C when O2:CH4 <1. High CH4 conversion of 97% is achieved at 750°C with corresponding H2 and CO selectivity of about 74 and 91%. The oxygen flux of the membranes also increased with the increase in oxygen partial pressure gradient across the membrane. The postreacted membranes were tested via XRD and FESEM‐EDX for their crystallinity and surface morphology. XPS analysis was further used to investigate the O1s, Co 2p and Sr 3d binding energies of the segregated elements from the reducing reaction environment. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3874–3885, 2013
Darbepoetin‐alfa and intravenous iron administration after autologous hematopoietic stem cell transplantation: A prospective multicenter randomized trial
Authors: Beguin Yves , Maertens Johan , De Prijck Bernard , Schots Rik , Seidel Laurence , Bonnet Christophe , Hafraoui Kaoutar , Willems Evelyne , Vanstraelen Gaetan , Servais Sophie , Jaspers Aurélie , Fillet Georges , Baron Frederic
Published: July 2013

We conducted a randomized study analyzing the impact of darbepoetin alfa (DA) administration with or without intravenous (i.v.) iron on erythroid recovery after autologous hematopoietic cell transplantation (HCT). Patients were randomized between no DA (Arm 1), DA 300 μg every 2 weeks starting on Day 28 after HCT (Arm 2), or DA plus i.v. iron 200 mg on Days 28, 42, and 56 (Arm 3). The proportion achieving complete hemoglobin (Hb) response within 18 weeks (primary end point) was 21% in Arm 1 (n = 24), 79% in Arm 2 (n = 25), and 100% in Arm 3 (n = 23; P < 0.0001). Erythropoietic response was shown to be significantly higher in Arm 3 (n = 46) than in Arm 2 (n = 50; P = 0.008), resulting in lower DA use, reduced drug costs, and improved quality of life scores, but the effect on transfusions was not significant. In multivariate analysis, DA administration (P < 0.0001), i.v. iron administration (P = 0.0010), high baseline Hb (P < 0.0001), and low baseline creatinine (P = 0.0458) were independently associated with faster achievement of complete Hb response. In conclusion, DA is highly effective to ensure full erythroid reconstitution after autologous HCT when started on Day 28 post‐transplant. I.v. iron sucrose further improves erythroid recovery. Am. J. Hematol. 88:990–996, 2013. © 2013 Wiley Periodicals, Inc.
MICROSCOPE – fabricating test masses for an in‐orbit test of the equivalence principle
Authors: Hagedorn Daniel , Heyne Heinz‐Peter , Metschke Stephan , Langner Uwe , Grüner Sven , Löffler Frank , Lebat Vincent , Rodrigues Manuel , Touboul Pierre
Published: July 2013

The MICROSCOPE space mission is to test in 2016 the Weak Equivalence Principle (WEP) with an accuracy of 10−15. This fundamental physics mission should provide answers to the basic question of the universality of free‐falling bodies in a uniform gravity field. During 18 months, the mission should improve the current ground experiments by at least two orders of magnitude. The payload is composed of two electrostatic differential space accelerometers that exhibit a resolution of 2×10−12 m s−2 Hz−1/2. By measuring the difference of acceleration between two concentric test masses at the orbital frequency, a possible WEP violation signal is extracted from the measurement where the gravity gradient effect dominates by a factor of one hundred.

This paper addresses the scientific objective of the space mission and describes how the performance drives the specification. A particular focus is made on the work jointly performed by ONERA and PTB to fulfil the fabricating requirements.
A new approach to test Lorentz invariance in the weak interaction
Authors: Wilschut Hans W. , Dijck Elwin A. , Hoekstra Steven , Jungmann Klaus , Müller Stefan E. , Noordmans Jacob P. , Onderwater Gerco , Pijpker Coen , Sytema Auke , Timmermans Rob G. E. , Vos K. Keri , Willmann Lorenz
Published: July 2013

Lorentz invariance has been tested rather poorly on the weak interaction in comparison to the electromagnetic interaction. This work discusses which tests on the weak interaction may be relevant. In particular, it considers exploiting the spin degrees of freedom in β decay for testing rotational invariance. The relation between the various phenomenological tests of Lorentz invariance is shown using a new theoretical framework.
Quantum information entropies for an asymmetric trigonometric Rosen–Morse potential
Authors: Sun Guo‐Hua , Dong Shi‐Hai , Saad Nasser
Published: July 2013

Shannon entropy for the position and momentum eigenstates of an asymmetric trigonometric Rosen–Morse potential for the ground and first excited states is evaluated. The position and momentum information entropies and are calculated numerically. Also, it is found that is obtained analytically and increases with the potential depth and width. Some interesting features of the information entropy densities and are demonstrated graphically. The Bialynicki‐Birula–Mycielski inequality is also tested and found to hold good.
Ultracold quantum gases and lattice systems: quantum simulation of lattice gauge theories
Authors: Wiese U.‐J.
Published: July 2013

Abelian and non‐Abelian gauge theories are of central importance in many areas of physics. In condensed matter physics, Abelian U(1) lattice gauge theories arise in the description of certain quantum spin liquids. In quantum information theory, Kitaev's toric code is a lattice gauge theory. In particle physics, Quantum Chromodynamics (QCD), the non‐Abelian gauge theory of the strong interactions between quarks and gluons, is non‐perturbatively regularized on a lattice. Quantum link models extend the concept of lattice gauge theories beyond the Wilson formulation, and are well suited for both digital and analog quantum simulation using ultracold atomic gases in optical lattices. Since quantum simulators do not suffer from the notorious sign problem, they open the door to studies of the real‐time evolution of strongly coupled quantum systems, which are impossible with classical simulation methods. A plethora of interesting lattice gauge theories suggests itself for quantum simulation, which should allow us to address very challenging problems, ranging from confinement and deconfinement, or chiral symmetry breaking and its restoration at finite baryon density, to color superconductivity and the real‐time evolution of heavy‐ion collisions, first in simpler model gauge theories and ultimately in QCD.
Synthesis and application properties of fluorinated aromatic copolymers
Authors: Ye Haohua , Li Zhanxiong , Chen Guoqiang
Published: July 2013

Aromatic monomers with different fluorine concentrations and structural distribution patterns were synthesized. A series of copolymers based on methyl methacrylate, acrylate, and perfluorooctylalkyl acrylate were prepared by emulsion polymerization and were subsequently used as functional coatings to prepare water‐ and oil‐repellent cotton fabrics. The composition and structure of the outmost layer of the treated cotton surface were analyzed. A strong surface segregation of fluorinated segments was found for the treated samples, as shown by X‐ray photoelectron spectroscopy analysis. The basis for an in‐depth appreciation of the relationship between the molecular structure of the monomers and the properties of corresponding copolymer‐treated materials was provided (especially with regarding to their hydrophobic and oleophobic properties). The wetting characteristics of the fluorinated copolymers were found to be dependent on the density (number of side chains per constitutional repeat unit) and regularity of the fluorinated side chains. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4410–4418, 2013
Cyclodextrin‐dendrimer functionalized polysulfone membrane for the removal of humic acid in water
Authors: Malinga Soraya P. , Arotiba Omotayo A. , Krause Rui W. M. , Mapolie Selwyn F. , Diallo Mamadou S. , Mamba Bhekie B.
Published: July 2013

Commercial polysulfone (PSf) membranes were crosslinked with a β‐cyclodextrin‐poly (propyleneimine) (β‐CD‐PPI) conjugate which had β‐CD pendant arms using trimesoyl chloride (TMC) by interfacial polymerization. The morphology and physicochemical properties of the nanofiltration membranes were characterized using Fourier transform infrared/attenuated total reflectance (FT‐IR/ATR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and cross‐flow filtration system. Water‐contact angle, water‐intake capacity, and rejection capacities of the membranes were evaluated. The β‐CD‐G4 (generation 4)‐PPI‐PSf and β‐CD‐G3 (generation 3)‐PPI‐PSf membranes both exhibited high humic acid rejection of 72% as compared to the commercial PSf which exhibited 57%. The modified membranes were also more hydrophilic (36° to 41°) than PSf (76°). These results suggest that β‐CD‐PPI nanostructures are promising materials for the synthesis of membranes for the removal of humic acid from water. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4428–4439, 2013
Seeking beyond with IntegraL: A user study of sense‐making enabled by anchor‐based virtual integration of library systems
Authors: Ho Shuyuan Mary , Bieber Michael , Song Min , Zhang Xiangmin
Published: July 2013

This article presents a user study showing the effectiveness of a linked‐based, virtual integration infrastructure that gives users access to relevant online resources, empowering them to design an information‐seeking path that is specifically relevant to their context. IntegraL provides a lightweight approach to improve and augment search functionality by dynamically generating context‐focused “anchors” for recognized elements of interest generated by library services. This article includes a description of how IntegraL's design supports users' information‐seeking behavior. A full user study with both objective and subjective measures of IntegraL and hypothesis testing regarding IntegraL's effectiveness of the user's information‐seeking experience are described along with data analysis, implications arising from this kind of virtual integration, and possible future directions.
A New Tridentate Sulfur Receptor as a Highly Sensitive and Selective Fluorescent Sensor for Cu2+ Ions
Authors: She Haiying , Song Fengling , Xu Juan , Xiong Xiaoqing , Chen Gengwen , Fan Jiangli , Sun Shiguo , Peng Xiaojun
Published: July 2013

The introduction of Lawesson′s reagent into a bis‐rhodamine spirolactam system afforded a new fluorescent sensor for Cu2+ ions, SRR, which contained a new tridentate sulfur ligand. SRR showed excellent specificity for Cu2+ ions over other cations (including Cu+, Hg2+, and Fe3+), very high sensitivity (10 nM), and a rapid response time (3 min). The detection mechanism was investigated by 1H NMR, 13C NMR, 31P NMR, and ESR spectroscopy, MS, and Gaussian calculations. Coordination of a Cu2+ ion to the tridentate sulfur ligand, which promotes ring‐opening of the rhodamine groups, followed by a spontaneous reduction reaction (Cu2+ into Cu+), has been proposed as the sensing mechanism.
Substituent and Solvent Effects on the Electrochemical Properties and Intervalence Transfer in Asymmetric Mixed‐Valent Complexes Consisting of Cyclometalated Ruthenium and Ferrocene
Authors: Wu Si‐Hai , Shao Jiang‐Yang , Kang Hong‐Wei , Yao Jiannian , Zhong Yu‐Wu
Published: July 2013

Four heterodimetallic complexes [Ru(Fcdpb)(L)](PF6) (Fcdpb=2‐deprotonated form of 1,3‐di(2‐pyridyl)‐5‐ferrocenylbenzene; L=2,6‐bis‐(N‐methylbenzimidazolyl)‐pyridine (Mebip), 2,2′:6′,2′′‐terpyridine (tpy), 4‐nitro‐2,2′:6′,2′′‐terpyridine (NO2tpy), and trimethyl‐4,4′,4′′‐tricarboxylate‐2,2′:6′,2′′‐terpyridine (Me3tctpy)) have been prepared. The electrochemical and spectroelectrochemical properties of these complexes have been examined in CH2Cl2, CH3NO2, CH3CN, and acetone. These complexes display two consecutive redox couples owing to the stepwise oxidation of the ferrocene (Fc) and ruthenium units, respectively. The potential difference, ΔE1/2 (E1/2(RuII/III)−E1/2(Fc0/+)), decreased slightly with increasing solvent donocity. The mixed‐valent states of these complexes have been generated by electrolysis and the resulting intervalence charge‐transfer (IVCT) bands have been analyzed by Hush theory. Good linear relationships exist between the energy of the IVCT band, Eop, and ΔE1/2 of four mixed‐valent complexes in a given solvent.
Kriging prediction from a circular grid: application to wafer diffusion
Authors: Pistone Giovanni , Vicario Grazia
Published: July 2013

In the production process of silicon wafers, which are crystalline slices used as substrate of electronic micro‐circuits, the thickness of the SiO2deposition on their top is a main characteristic to be controlled during the process. The experimental design that is commonly used to monitor the thickness to the target value consists of a regular array of points lying on concentric circles, the silicon wafer itself being a disk. To speed up the control process, the engineers aim to use just only a limited subset of such points. To reconstruct the values on untried locations of the silicon wafer, the Kriging interpolation has been proposed because of its recognized ability in providing fairly good predictions. In this paper, we consider two methodological issues related to universal Kriging models. First, we discuss the modeling of the covariance structure among the measured points; in fact, spatial data usually show a strong correlation when they come from spatially near observed points. Second, we put forward an algebraic method to assess the identifiability of trend models, based both on the full experimental design and on special fractions of it. Our findings are illustrated by a data set from an industrial application. Copyright © 2013 John Wiley & Sons, Ltd.
Design and activity of novel lactoferrampin analogues against O157:H7 enterohemorrhagic escherichia coli
Authors: Cruz Jenniffer , Ortiz Claudia , Guzmán Fanny , Cárdenas Constanza , Fernandez‐Lafuente Roberto , Torres Rodrigo
Published: July 2013

Lactoferrampin 265–284 (LFampin 265–284) is a peptide consisting of residues 265–284 of N1‐domain of bovine Lactoferrin (LF). This peptide has several cationic groups in the C‐terminal lobe, exhibiting an antibacterial activity against a wide range of microorganisms. However, LFampin 265–284 exhibits low antimicrobial activity against the O157:H7 enterohaemorrhagic Escherichia coli (EHEC O157:H7) when compared with Lactoferrin chimera and Lactoferricin. Here, we have designed three analogues of LFampin 265–284 based on the distribution of cationic groups, hydrophobicity, size, and sequence. Analogues were synthesized by solid phase chemistry using Fmoc methodology obtaining peptides with 95% purity. All peptides maintain the ability to adopt helical conformations (checked by circular dichroism spectra and molecular simulations). Some of these analogues exhibited a significant increase in antimicrobial activity by counting colony forming units against EHEC O157:H7 compared to native LFampin 265–284, with MIC of 10 and 40 µM for 264G‐D265K and 264G‐D265K/S272R, respectively. The incorporation of a GKLI sequence in the N‐terminal lobe increased dramatically its antibacterial activity, an effect which has been attributed to the addition of cationic groups in the N‐terminal side that may stabilize the helical conformation of the new designed peptides. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 319–328, 2014.
Responsible Innovation Toward Sustainable Development in Small and Medium‐Sized Enterprises: a Resource Perspective
Authors: Halme Minna , Korpela Maria
Published: July 2013

What resources do small enterprises need to develop responsible innovations that enhance sustainable development? Does lack of resources prevent innovation toward sustainability in small and medium‐sized enterprises (SMEs) or can innovations be created with scarce resources? This study investigates environmentally and socially responsible innovations of SMEs from a resource perspective, based on empirical data from 13 Nordic SMEs. The findings indicate that SMEs can create responsible innovations with very different resource combinations. The most common resource combination comprises equity, research and development cooperation, networks, industry knowledge and reputation. Except for financial capital in the form of equity, which appears a necessary condition for responsible innovation from SMEs, resource needs vary between technological and business model innovations. Creating business model innovations appears to be possible with scarce resources, at the very least with equity and social capital. Environmental technology innovations call for more abundant resource combinations. In particular industry knowledge appears to be a key resource for such innovations. Copyright © 2013 John Wiley & Sons, Ltd and ERP Environment