bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive modulation and decision feedback equalization for frequency‐selective MIMO channels
Authors: Ammari Mohamed Lassaad , Zaouali Kalthoum , Fortier Paul
Published: April 2013

In this paper, an adaptive modulation scheme for the multiple‐input multiple‐output (MIMO) frequency‐selective channels is investigated. We consider a scenario with precoded block‐based transceivers over spatially correlated Rayleigh multipath MIMO channels. To eliminate the inter‐block interference, the zero‐padding is used. The receiver is equipped with a MIMO minimum‐mean‐squared‐error decision feedback equalizer. The precoder aims to force each subchannel to have an identical signal‐to‐interference‐plus‐noise ratio (SINR). To adjust the constellation size, the unbiased mean square error at the equalizer output is sent back to the transmitter. To simplify our analysis, the feedback channel is considered as instantaneous and error free. We first derive the probability density function of the overall SINR for flat fading and frequency‐selective channels. On the basis of the probability density function of the upper bound of the SINR, we evaluate the system performance. We present accurate closed‐form expressions of the average spectral efficiency, the average bit error rate and the outage probability. The derived expressions are compared with Monte Carlo simulation results. Furthermore, we analyze the effect of the channel spatial correlation. Copyright © 2013 John Wiley & Sons, Ltd.
Sequence‐based separation of single‐strandedDNAusing nucleotides in capillary electrophoresis: Focus on phosphate
Authors: Zhang Xueru , McGown Linda B.
Published: April 2013

DNAanalysis has widespread applicability in biology, medicine, biotechnology, and forensics.DNAseparation by length is readily achieved using sieving gels in electrophoresis. Separation by sequence is less simple, generally requiring adequate differences in native or induced conformation or differences in thermal or chemical stability of the strands that are hybridized prior to measurement. We previously demonstrated separation of four single‐strandedDNA76‐mers that differ by only a fewA‐Gsubstitutions based solely on sequence using guanosine‐5′‐monophosphate (GMP) in the running buffer. We attributed separation to the unique self‐assembly ofGMPto form higher order structures. Here, we examine an expanded set of 76‐mers designed to probe the mechanism of the separation and effects of experimental conditions. We were surprised to find that other ribonucleotides achieved the similar separation toGMP, and that some separation was achieved using sodium phosphate instead ofGMP. Potassium phosphate achieved almost as good separations as the ribonucleotides. This suggests that the separation medium provides a physicochemical environment for theDNAthat effects strand migration in a sequence‐selective manner. Further investigation is needed to determine whether the mechanism involves specific interactions between the phosphates and theDNAstrands or is a result of other properties of the separation medium. Phosphate generally has been avoided inDNAseparations by capillary gel electrophoresis because its high ionic strength exacerbates Joule heating. Our results suggest that phosphate compounds should be examined for separation ofDNAbased on sequence.
Control Structure Design for CO2‐Absorption Processes with Large Operating Ranges
Authors: Schach Marc‐Oliver , Schneider Rüdiger , Schramm Henning , Repke Jens‐Uwe
Published: April 2013

Coal‐fired power plants are operated flexibly over a large operating range, with variations in flue‐gas mass flow rate and composition. Postcombustion absorption processes are used to separate the CO2 from the flue gas at every operating point in the most economical way. Maintaining an economically feasible operation is the objective of the control structure. In this work the control structures were designed using a self‐optimizing control procedure for two process configurations. The control structures allow for an economic operation with a power‐plant load in the range of 40–100 %. The loss of the designed feedback‐control structures in comparison to an optimized control at every operating point was between 0.57 and 2.64 % in terms of cost of CO2 avoided.
Two New Sesquiterpenes from the Roots of Valeriana faurieiBriq.
Authors: Liu Xue‐Gui , Zhang Weng‐Chao , Gao Pin‐Yi , Wang Guo‐Sheng , Li Ling‐Zhi , Song Shao‐Jiang , Zhang Xiang , Yao Xin‐Sheng , Liu Ke , Zhang Zhen‐Xue
Published: April 2013

A phytochemical investigation of the MeOH extract of Valeriana fauriei Briq. roots resulted in the isolation of two new sesquiterpenes, isovalerianin A (=(1β,4Z,6β,8α)‐8‐(acetyloxy)‐1,10‐dihydroxy‐6,11‐cyclogermacr‐4‐en‐15‐al=rel‐(1R,2Z,6S,7R,9R,10S)‐9‐(acetyloxy)‐6,7‐dihydroxy‐7,11,11‐trimethylbicyclo[8.1.0]undec‐2‐ene‐3‐carboxaldehyde; 1) and valerianin C (=(2α,3α,6α,8α)‐3‐(acetyloxy)‐2,4,8‐trihydroxyguai‐1(10)‐ene‐12,6‐lactone=rel‐(3R,3aS,4R,7S,8S,9R,9aR,9bR)‐8‐(acetyloxy)‐3a,4,5,7,8,9,9a,9b‐ octahydro‐4,7,9‐trihydroxy‐3,6,9‐trimethylazuleno[4,5‐b]furan‐2(3H)‐one; 2), together with six known compounds, i.e., camphor, methyl 4‐hydroxybenzoate, 2‐methoxybenzoic acid, benzoic acid, quercetin, and kaempferol. The structures of the compounds were established by detailed spectral analysis and comparison with previously reported data.
Three New Sesquiterpenes from Laggera pterodonta
Authors: Zhang Zhi‐Jun , He Juan , Li Yan , Wu Xing‐De , Gao Xiu , Peng Li‐Yan , Cheng Xiao , Li Rong‐Tao , Zhao Qin‐Shi
Published: April 2013

A new eremophilane sesquiterpene, (2β)‐2‐deoxo‐2‐methoxytessaric acid (1), and two new eudesmane sesquiterpenes, (3β,10α)‐3‐methoxyleudesma‐4,11(13)‐dien‐12‐oic acid (2) and (3α,4β,8α)‐4‐(acetyloxy)‐3‐(2,3‐dihydroxy)‐2‐methyl‐1‐oxobutoxy‐8‐hydroxyeudesm‐7(11)‐eno‐12,8‐lactone (3), along with the ten known compounds 4–13 were isolated from the aerial parts of Laggera pterodonta. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D‐NMR data.
A Simple Synthesis of 2‐{(Arylmethylidene)hydrazinylidene]‐3‐hydroxy‐4H‐furo[3,2‐c]pyran‐4(3H)‐ones
Authors: Adib Mehdi , Ansari Samira , Zhu Long‐Guan , Rahimi‐Nasrabadi Mehdi
Published: April 2013

A simple synthesis of 2‐hydrazinylidene‐3‐hydroxy‐4H‐furo[3,2‐c]pyran‐4‐ones is described. A mixture of (isocyanoimino)(triphenyl)phosphorane, an aromatic aldehyde, and dehydroacetic acid (=3‐acetyl‐2‐hydroxy‐6‐methyl‐4H‐pyran‐4‐one) undergo a 1 : 1 : 1 addition reaction under mild conditions to afford the title compounds in excellent yields.
A Convenient Synthesis of 2,3‐Dihydro‐4H‐thiopyrano[2,3‐b]‐, ‐[2,3‐c]‐, or ‐[3,2‐c]pyridin‐4‐ones by the Reaction of the Corresponding 1‐(Chloropyridinyl)alk‐2‐en‐1‐ones with NaSH
Authors: Kobayashi Kazuhiro , Imaoka Ayumi
Published: April 2013

2,3‐Dihydro‐4H‐thiopyrano[2,3‐b]pyridin‐4‐ones 4 were prepared by a three‐step sequence from commercially available 2‐chloropyridine (1). Thus, successive treatment of 1 with iPr2NLi (LDA) and α,β‐unsaturated aldehydes gave 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ols 2, which were oxidized with MnO2 to 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ones 3. The reactions of 3 with NaSH⋅n H2O proceeded smoothly at 0° in DMF to provide the desired thiopyranopyridinones. Similarly, 2,3‐dihydro‐4H‐thiopyrano[2,3‐c]pyridin‐4‐ones 8 and 2,3‐dihydro‐4H‐thiopyrano[3,2‐c]pyridin‐4‐ones 12 were obtained starting from 3‐chloropyridine (5) and 4‐chloropyridine (9), respectively.
Type of Writing Task and College Students' Meaning Making Following a Romantic Breakup
Authors: Primeau Joanna E. , Servaty‐Seib Heather L. , Enersen Donna
Published: April 2013

In this study, the authors examined the potential effects of type of writing task (loss/gain vs. general prompt) on the narrative content offered by college students (N= 41) who experienced romantic breakup. Qualitative analyses indicated differences based on type of writing task. Students who received the loss/gain prompt exhibited more cognitive, balanced, and complex responses, whereas those who received the general prompt offered more emotional and factual accounts of their experience.
Analysis of acetic acid, furfural and 5‐hydroxymethylfurfural affecting 2, 3‐butanediol production using Klebsiella oxytoca
Authors: Wu Jing , Cheng Ke‐Ke , Wang Gen‐Yu , Li Wen‐Ying , Feng Jie , Zhang Jian‐An
Published: April 2013

BACKGROUND

The effect of the combination of acetic acid, furfural and 5‐hydroxymethylfurfural on 2, 3‐butanediol fermentation of Klebsiella oxytoca was studied by statistical analysis. The compounds were selected taking into account their concentration in the hydrolysate from the acid pretreatment of biomass and their toxicity. A central composite design was used to investigate the influences of these compounds on 2, 3‐butanediol yield and biomass formation.

RESULTS

Two models were developed to describe the effect of the combination of acetic acid, furfural and 5‐hydroxymethylfurfural on biomass and product yield in 2, 3‐butanediol fermentation. The proposed model is suited to fit experimental data and to simulate cell growth and 2, 3‐butanediol yield, which was confirmed by 2, 3‐butanediol production using real hydrolysate as substrate.

CONCLUSION

Biomass yield was affected mainly by the ‘main effects’ of the tested compounds and no interaction relationship among acetic acid, furfural and HMF was found. 2, 3‐butanediol yield was more sensitive to acetic acid concentration. Selective removal of furfural in hydrolysate would contribute to the simultaneous improvement of 2, 3‐butanediol yield and cell growth. © 2013 Society of Chemical Industry
Synthesis and Antitumor Evaluation of Some New Fused and Binary Pyridines
Authors: Waly Mohamed A. , EL‐Hawary Ibrahim I. , Hamama Wafaa S. , Zoorob Hanafi H.
Published: April 2013

Syntheses of some new heterocyclic compounds containing pyridone, thioxopyridine, halogenated‐pyridine‐carbonitriles, pyrazolopyridine, and pyridine derivatives were achieved. Besides, a modified synthetic method for the synthesis of 2‐chloro‐4,6‐dimethyl‐nicotinonitrile (3) through the reaction of acetylacetone and malononitrile as starting materials was implemented. The reaction of 2‐chloronicotinonitrile 3 with substituted amines to 2‐aminonicotinonitrile were also investigated. Fused or binary pyridines were tested for cytotoxicity against well‐known established model Ehrlich ascites cells in vitro. Compound 13 exhibited a high antitumor activity compared with 5‐fluorouracil.
Potassium Carbonate‐Mediated Green and Efficient Synthesis of Imidazo[2,1‐b]‐1,3,4‐thiadiazoles Using PEG as Solvent
Authors: Kidwai Mazaahir , Bhatnagar Divya , Chauhan Ritika
Published: April 2013

Polyethylene glycol (PEG) was found to be an inexpensive nontoxic and effective medium for the synthesis of imidazo[2,1‐b]‐1,3,4‐thiadiazoles in the presence of potassium carbonate as a green base in high yields. In addition, the solvent system can be recovered and reused, making this protocol economically and potentially viable.
Zeolite‐Supported One‐Pot Synthesis of Bis‐azetidinones under Microwave Irradiation
Authors: Jetti Venkateshwarlu , Pagadala Ramakanth , Meshram Jyotsna S. , Chopde Himani N. , Malladi Latha
Published: April 2013

In an attempt to synthesize antibacterial agents effective against gram‐positive and gram‐negative bacteria, the efficient synthesis of novel bis‐azetidinones (3a–j) has been established. Thus, cycloaddition reaction of substituted bis‐imines with chloroacetylchloride under microwave irradiation in the presence of zeolite yielded bis‐azetidinones (3a–j). Structures of the synthesized compounds have been elucidated on the basis of their elemental analysis and spectral data (IR,1H‐NMR,13C‐NMR, and mass spectra). The synthesized bis‐azetidinones were screened for their antibacterial activity against five microorganisms:Bacillus subtilis,Proteus vulgaris,Staphylococcus aureus,Klebsiella pneumoniae, andEscherichia coli. They were found to exhibit good to moderate antibacterial activity.
Synthesis and Dynamic NMR Studies of Some New Symmetrical Podands of Dithiocarbamates Formed from Bis(N‐thiazol)chloroacetamides
Authors: Shockravi Abbas , Kamali Mahmood , Halimehjani Azim Ziyaei , Jafari Reza
Published: April 2013

Reactions of dithiocarbamates salts (IVa, IVb, IVc) with bis(N‐thiazol) chloroacetamides(IIa, IIb) in DMF furnished corresponding podands as Va, Vb, Vc, Vd, Ve, Vf in high to excellent yields. Two reacting ligands (IIa, IIb) were obtained in the reaction of bis(aminothiazoles) (Ia, Ib) with chloroacetyl chloride. Dynamic NMR spectroscopic data of two series of podands (Va, Vb, Vc and Vd, Ve, Vf) are discussed and figured out their free energy of activation () at coalescence temperatures. The s of these podands were attributed to conformational isomerization in the range of 14.9–16.2 kcal/mol due to rotation and resonance effect about thioamide C―N bond.
Diffusion tensor imaging (DTI) of the normal human uterus in vivo at 3 tesla: Comparison of DTI parameters in the different uterine layers
Authors: Fujimoto Koji , Kido Aki , Okada Tomohisa , Uchikoshi Masato , Togashi Kaori
Published: April 2013

Purpose

To investigate the differences in the fiber architecture and related diffusion tensor imaging (DTI) parameters among different uterine layers of the normal human uterus in vivo at 3 Tesla (T).

Materials and Methods

DTI of the uterus was performed for nine healthy women of reproductive age on a 3T scanner. A volume of interest (VOI) was drawn for the outer myometrium (OM), junctional zone (JZ), and endometrium (EM). Apparent diffusion coefficient (ADC), fractional anisotropy (FA), and maximum fiber length were compared using paired Student's t‐tests. Fibers were classified into four groups and were visually evaluated.

Results

ADC (×10−3 mm2/s) was highest for OM (1.12), followed by EM (0.97) and JZ (0.83) (OM versus JZ, P < 0.0001; JZ versus EM, P = 0.0001; OM versus EM, P = 0.0057). FA was highest for JZ (0.297), followed by OM (0.257) and EM (0.186) (OM versus JZ, P = 0.0002; JZ versus EM, P < 0.0001; OM versus EM, P < 0.0001). Fibers were longest in OM (42.0 mm), followed by JZ (34.2 mm) and EM (20.0 mm). Circularly oriented fibers were observed in 69% in OM and in 70% in JZ.

Conclusion

DTI of the uterus in vivo revealed layer‐wise differences in the microstructure of the uterus. J. Magn. Reson. Imaging 2013;38:1494–1500. © 2013 Wiley Periodicals, Inc.
Traditional foods from the Black Sea region as a potential source of minerals
Authors: Albuquerque Tânia G , Costa Helena S , Sanches‐Silva Ana , Santos Mariana , Trichopoulou Antonia , D'Antuono Filippo , Alexieva Iordanka , Boyko Nadiya , Costea Carmen , Fedosova Katerina , Karpenko Dmitry , Kilasonia Zaza , Koçaoglu Bike , Finglas Paul
Published: April 2013

BACKGROUND

In the past few years, minerals have assumed great importance in public health. As a consequence, considerable research has been carried out to better understand their physiological role and the health consequences of mineral‐deficient diets, to establish criteria for defining the degree of public health severity of malnutrition, and to develop prevention and control strategies. In most countries, there is limited information on the mineral content of traditional foods, and consequently it is very difficult to estimate mineral intake across these countries.

RESULTS

Ten minerals were quantified in 33 traditional foods from Black Sea area countries. Our results indicate a considerable variability among the analysed traditional foods; nevertheless, the most abundant components were sodium (ranging from 40.0 to 619 mg 100 g−1, for kvass southern and herbal dish, respectively), potassium (varied between 45.5 mg 100 g−1 for millet ale and 938 mg 100 g−1 for roasted sunflower seeds), and phosphorus (22.2 mg 100 g−1 and 681 mg 100 g−1 for sauerkraut and roasted sunflower seeds, respectively).

CONCLUSION

This is the first study that provides validated data on the mineral content for 33 traditional foods from Black Sea area countries, which is important in order to elucidate their role in the dietary pattern of populations and to preserve and promote these foods. © 2013 Society of Chemical Industry
Immobilized endoproteinase Glu‐C to magnetic bead cellulose as a tool in proteomic analysis
Authors: Prikryl Petr , Ticha Marie , Kucerova Zdenka
Published: April 2013

Magnetic bead cellulose activated with divinyl sulfone was used for the immobilization of Staphylococcus aureus endoproteinase Glu‐C (EC 3.4.21.19). The immobilized proteinase was characterized by increased thermostability, by decreased self‐cleavage activity, and a possibility of repeated use. The prepared immobilized enzyme was applied for the proteolytic cleavage of α‐casein and BSA under different conditions (different composition of buffers, different pH, and different time of digestion). The possibilities of the direct use of enzyme reaction products for MALDI TOF MS analysis were shown.
Phase of nasal cycle during sleep tends to be associated with sleep stage
Authors: Kimura Akihiro , Chiba Shintaro , Capasso Robson , Yagi Tomoko , Ando Yuji , Watanabe Subaru , Moriyama Hiroshi
Published: April 2013

Background and Objectives

The phenomena of periodic cycles of vascular engorgement on the nasal cavity mucosa that alternate between right and left sides are termed the “nasal cycle.” The physiologic mechanisms underlying this cycle have not been entirely clarified, even more so during sleep. In this study, we measured the periodic patterns of the normal nasal cycle, not only during wakefulness but also during sleep.

Study Design: Case Series Methods

Our team utilized a method for functional rhinologic assessment, the portable rhinoflowmeter (Rhinocycle, Rhinometrics, Lynge, Denmark), measuring airflow independently through each nostril during 24 hours on 20 healthy subjects aged 20 to 56 years, and without any nasal pathology or diagnosed medical, psychiatric, or sleep disorders. In addition, a nocturnal polysomnogram was simultaneously performed during sleep.

Results

Nineteen of 20 subjects showed a detectable nasal cycle, and 16 of 19 subjects presented a change of the cyclic phase during sleep. The mean nasal cycle duration was 234.2±282.4 minutes (median, 164.1 minutes), although variation was considerable. The mean cycle duration time during sleep was significantly longer than that in wakefulness (P <0.005). The reversal of cyclic phase during sleep tended to be associated with REM sleep (68.8%) and postural changes (18.8%). It never occurred in slow‐wave sleep.

Conclusions

Nasal cycle duration during sleep is longer than in wakefulness. Changes in laterality of nasal cycle frequently coincide with switches in posture, tend to occur in REM sleep, never occur in slow‐wave sleep, and may be absent in subjects with severe nasal septal deviations.

Level of Evidence

4. Laryngoscope, 123:2050–2055, 2013
Eustachian tube function as a predictor of the recurrence of middle ear effusion in children
Authors: Mandel Ellen M. , Swarts J. Douglas , Casselbrant Margaretha L. , Tekely Kathleen K. , Richert Beverly C. , Seroky James T. , Doyle William J.
Published: April 2013

Objectives/Hypothesis

In children with ventilation tubes (VTs) inserted for chronic otitis media with effusion (COME), the authors sought to determine whether any parameter of Eustachian tube (ET) function measured by the forced response test (FRT) predicts disease recurrence after the VT becomes nonfunctional.

Study Design

Prospective study of those factors that predict disease recurrence in children with VTs inserted for COME.

Methods

Forty‐nine subjects (73 ears; 28 male, 34 white, aged 5.3 ± 1.2 years) with COME had VTs inserted and were evaluable for disease status after the VT(s) became nonfunctional. The FRT was done when the VTs were patent, and results for the last test before the VT became nonfunctional were used in the analysis. After each VT became nonfunctional, the children were followed for disease recurrence over a 12‐month period. Logistic regression was used to determine whether the ET opening pressure, closing pressure, and/or dilatory efficiency predicted disease recurrence. That model was expanded to include age, sex, race, history of adenoidectomy, previous VTs, and duration of VT patency as potential predictive factors.

Results

Twenty‐nine (40%) ears had recurrence of significant disease within 12 months after the VT became nonfunctional. For the complete logistic regression model, male gender (P = .03), nonwhite race (P = .02), shorter period of VT patency (P = .01), and low dilatory efficiency (P = .01) were significant predictors of disease recurrence.

Conclusions

A measure of active ET function, dilatory efficiency, but not measures of passive function predicted disease recurrence within the 12 months after the VT became nonfunctional in children with COME.

Level of Evidence

4 Laryngoscope, 123:2285–2290, 2013
Obstructive sleep apnea after radial forearm free flap reconstruction of the oral tongue
Authors: Gilat Hanna , Shpitzer Thomas , Guttman Dan , Soudry Ethan , Feinmesser Raphael , Bachar Gideon
Published: April 2013

Objectives/Hypothesis

To determine whether radial forearm free flap reconstruction of the tongue after partial glossectomy is associated with obstructive sleep apnea.

Study Design

Retrospective case series.

Methods

Fifteen patients (5 men, 10 women) treated for tongue cancer in 2006–2010 by partial glossectomy and immediate radial forearm free flap reconstruction completed the Epworth Sleepiness Scale and underwent polysomnographic studies. Background, clinical, and pathologic data were collected from the medical files.

Results

Mean ± SD age of the study group was 57 ± 19 years; body mass index, 24 ± 4; follow‐up, 5.6 ± 2.8 years. Mean ± SD Epworth scale score was 8.18 ± 6.18 (normal, <8). Disordered sleep was documented in 11 patients, of whom 8 (53.3% of the cohort) had OSA (5 mild, 2 moderate, 1 severe). The OSA rate was significantly higher than reported in the general population (P = 0.001).

Conclusion

Patients after partial glossectomy and radial forearm free flap reconstruction appear to be at high risk of obstructive sleep apnea. Testing for OSA should be considered in these patients.

Level of Evidence

Level IV. Laryngoscope, 123:3223–3226, 2013
Tradeoffs in the Rehabilitation of a Succulent Karoo Rangeland
Authors: Hanke Wiebke , Wesuls Dirk , Münchberger Wiebke , Schmiedel Ute
Published: April 2013

Rangeland rehabilitation has multiple, sometimes conflicting goals, such as the reestablishment of the predisturbance vegetation, soil protection, and forage production. The rehabilitation techniques should be also cost‐effective and practicable. Given the difficulties and high costs of restoring Succulent Karoo rangelands and the continuously high grazing pressure in the communal lands, tradeoffs should be accepted in the achievement of these goals. We tested the capability of paddock manure redistribution to reverse degradation trends in a heavily grazed Succulent Karoo rangeland in South Africa. Over 3 years, the effects of the manure application were compared with areas planted with mature shrubs as a benchmark for a predisturbance vegetation structure and with four popular rehabilitation techniques: (1) livestock exclusion; (2) brushpacking (coverage of dead shrubs); (3) mineral fertilizing; and (4) microcatchment construction. Manure was, besides planting, the only treatment that resulted in a significant increase in drought‐resistant vegetation cover, but it compromised the dominance of native vegetation. In the manure plots, a pasture‐like vegetation of non‐native forage plants (which germinated mainly from seeds in the dung), developed (foremost Atriplex semibaccata). Manure application counteracted erosion as effectively as the planted shrubs and brushpacks. Expected negative side effects such as a decrease in plant species richness or salinization of topsoil were not detected. We also checked the potential of topsoil salinization by the halophytic A. semibaccata and found it to be low. For sites where a decrease in grazing pressure is unrealistic under current land tenure, redistribution of manure should be further explored to mitigate acute symptoms of degradation. Copyright © 2013 John Wiley & Sons, Ltd.
Pulling Polymers on Energetically Disordered Surfaces: Molecular Dynamics Tests of Linear and Non‐linear Response
Authors: Raos Guido , Sluckin Timothy J.
Published: April 2013

Equilibrium and non‐equilibrium molecular dynamics simulations of flexible polymer chains absorbed on heterogeneous surfaces are presented. The surfaces are flat but energetically disordered, consisting of a random mixture of weakly and more strongly absorbing sites (94 and 6%, respectively). For comparison, the two corresponding homogeneous surfaces are also simulated. This apparently weak energetic disorder can produce significant changes of the chain statistics, equilibrium dynamics, and non‐equilibrium response to a horizontal pulling force. On the disordered surfaces, the polymer–surface effective friction coefficient becomes strongly force‐dependent, as the dominant mode of motion changes from localized stick–slip events to smooth and continuous sliding. This is strongly reminiscent of the Schallamach model of rubber friction and the Maier–Göritz picture of the Payne effect in filled elastomers.

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Percolation in Two‐Dimensional Copolymer Systems
Authors: Polanowski Piotr , Wawrzyńska Edyta , Sikorski Andrzej
Published: April 2013

The aim of the study is the investigation of the percolation phenomena in some model copolymer systems. Diblock, triblock, random copolymers, and a blend of homopolymers are studied. For this purpose, we developed an idealized model of polymeric systems. The positions of polymer segments are restricted to vertices of a simple cubic lattice. The chains are at good solvent conditions – the excluded volume is the only interaction between the segments of the chain. The properties of the model chains are determined by means of Monte Carlo simulations with a sampling algorithm based on chain's local changes of conformation. The differences and similarities in the percolation behavior are shown and discussed. The percolation threshold is found to be very weakly dependent on the chain length, however, it appears that the main factor that influenced the percolation threshold is the screening effect of other parts of chains.

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Cost‐effectiveness of deep brain stimulation in patients with Parkinson's disease
Authors: Dams Judith , Siebert Uwe , Bornschein Bernhard , Volkmann Jens , Deuschl Günther , Oertel Wolfgang H. , Dodel Richard , Reese Jens‐Peter
Published: April 2013

In addition to medical treatment, deep brain stimulation has become an alternative therapeutic option in advanced Parkinson's disease. High initial costs of surgery have to be weighted against long‐term gains in health‐related quality of life. The objective of this study was to assess the cost‐effectiveness of deep brain stimulation compared with long‐term medical treatment. We performed a cost‐utility analysis using a lifetime Markov model for Parkinson's disease. Health utilities were evaluated using the EQ‐5D generic health status measure. Data on effectiveness and adverse events were obtained from clinical studies, published reports, or meta‐analyses. Costs were assessed from the German health care provider perspective. Both were discounted at 3% per year. Key assumptions affecting costs and health status were investigated using one‐way and two‐way sensitivity analyses. The lifetime incremental cost‐utility ratio for deep brain stimulation was €6700 per quality‐adjusted life year (QALY) and €9800 and €2500 per United Parkinson's Disease Rating Scale part II (motor experiences of daily living) and part III (motor examination) score point gained, respectively. Deep brain stimulation costs were mainly driven by the cost of surgery and of battery exchange. Health status was improved and motor complications were reduced by DBS. Sensitivity analysis revealed that battery life time was the most influential parameter, with the incremental cost‐utility ratio ranging from €20,000 per QALY to deep brain stimulation dominating medical treatment. Deep brain stimulation can be considered cost‐effective, offering a value‐for‐money profile comparable to other well accepted health care technologies. Our data support adopting and reimbursing deep brain stimulation within the German health care system. © 2013 Movement Disorder Society
Birefringence control by hydrogen bonding on compatible polymer pair composed of hydrogenated ring‐opening polymer and modified polystyrene
Authors: Okaniwa Motoki , Kawashima Naoyuki , Kaizu Michitaka , Mutsuga Yasuaki
Published: April 2013

A new polymer blend composed of a hydrogenated ring‐opening polymer (HROP) with an ester group and hydroxyl functionalized polystyrene (HFP) produced the excellent transparent materials which enabled a precise birefringence control in keeping with the other physical properties for optical film use. The blend with a composition from 0.28 to 0.35 for the HFP weight fraction showed an extraordinary wavelength dispersion, transmitting through a zero birefringence point at the critical fraction of 0.45, while each polymer showed an ordinary wavelength dispersion. The observed excellent transparency even above those of the glass transition temperature was attributed to a depressed phase separation that resulted from strong hydrogen bond between the ester and hydroxyl groups. An IR analysis of the film demonstrated a remarkable red‐shift in the carbonyl peak with an increase of the hydroxylated polystyrene content, indicating a strong hydrogen bond between those groups. This new polymer blend provides a useful design to achieve practical demands for film use, both optical and mechanical under the fabrication conditions using the melt extrusion technique. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3132–3143
Planar reference electrodes on multielectrode arrays for electrochemical measurements of ionic currents
Authors: Schnitker Jan , Afanasenkau Dzmitry , Wolfrum Bernhard , Offenhäusser Andreas
Published: April 2013

We describe the fabrication process and characterization of polymer coated multielectrode array chips featuring 64 planar Ag/AgCl electrodes for electrophysiological and electrochemical measurements of ionic currents. The multielectrode chip consists of platinum feedlines and microelectrodes fabricated on an oxidized silicon substrate. The feed lines are passivated with a polyimide layer. Silver is deposited electrochemically on the platinum electrodes and chlorinated afterwards resulting in stable micro Ag/AgCl reference electrodes that are recessed within picoliter cavities. We envisage the chip as a platform for high‐throughput investigation of lipid bilayers.

Schematics of a planar reference electrode. The chips are processed on oxidized silicon (blue) and consist of Pt feedlines (yellow), the Ag/AgCl electrode (black) passivated with polyimide (light blue).
USING AN INTEGRATED MODELLING APPROACH FOR RISK ASSESSMENT OF THE ‘KILLER SHRIMP’ Dikerogammarus villosus
Authors: Boets P. , Pauwels I. S. , Lock K. , Goethals P. L. M.
Published: April 2013

The aim of this study was to predict the future distribution of an invasive macroinvertebrate species, Dikerogammarus villosus, under changing environmental conditions. For this, we used an integrated modelling approach. First, a habitat suitability model (HSM) was constructed on the basis of a regression tree model, to determine the preferred chemical water quality conditions. Subsequently, this HSM was combined with a chemical water quality model that makes predictions on future water quality scenarios for the year 2015 and 2027. It was expected that the area of suitable habitat of D. villosus would increase with improving water quality conditions in the future. Finally, migration speed was incorporated to model the spatial–temporal spread of D. villosus based on a network analysis. On the basis of monitoring data of Flanders (Belgium), it was calculated that D. villosus is able to spread with an average speed of 5 km year−1.The model simulations indicate that the species is primarily present in large rivers and canals with a good chemical water quality. With improving water quality, the species will be able to colonize additional watercourses, mainly because of a decrease in chemical oxygen demand and orthophosphate concentration. A validation based on the observed occurrence shows that the model accurately predicts areas with a high suitability that are most likely to be invaded by D. villosus. Our integrated modelling approach is useful as a practical method to perform risk assessment for watercourses that are vulnerable to invasions not only in Flanders but also in the whole world. Copyright © 2013 John Wiley & Sons, Ltd.
The problem of hot spots in microwave equipment used for preparatory techniques—Theory and practice
Authors: Kok L. P. , Boon Mathilde E. , Smid H. M.
Published: April 2013

Electron microscopists who wants to use a microwave (MW) oven to stimulate preparatory processes are sooner or later confronted with the problem of hot spots. It soon becomes clear to the user of any MW oven that the energy distribution—thus the speed of absorbing energy, and hence warming up—varies topographically. The unaware can observe variations in results when the principles of topographic order are not followed meticulously. To understand the hot‐spot phenomenon a certain theoretical knowledge is needed, as presented in this paper. In the 10 years that we have used MW ovens for our preparatory techniques we have learned how to solve the problem of hot spots. Thermographic paint can be applied to record energy distribution. In our studies, we have used a fiberoptic thermometer to follow precisely in time the temperature in the MW‐exposed media, and these observations have provided us with the needed insight to obtain reproducible results. We argue that only when temperature curves are given by the authors can their recipes be used successfully in other laboratories.
A model to determine microwave‐stimulated cross‐linking of collagen using diluted glutaraldehyde solutions
Authors: Ruijgrok J.M. , De Wijn J.R. , Boon M.E.
Published: April 2013

The model presented shows the effect of various fixation conditions on glutaraldehyde (GA) cross‐linking of collagen. The model consists of 10 very thin (10μm) synthetic collagen sheets, and by determining the degree of cross‐linking from the outer two sheets to the core region one can study the quality of fixation. The extent of cross‐linking is assessed by measuring the shrinkage temperature (Ts) of each separate sheet. The degree of cross‐linking and the distribution of cross‐links is visualized by plotting the Ts against the position of the sheet within the model, thus forming Ts profiles. Experiments were carried out to study the effect on the degree of cross‐linking of short‐term microwave‐stimulated fixation (5 min, 45°C) using low GA concentration (0.1%) and of a combination of GA presoaking at low or room temperature, (0°C) followed by short‐term (<3 min) heating to 45°C Short‐term fixation at 45°C caused an increase in Ts of more than 10°C in the central sheets and more than 20°C in the outer sheets. Presoaking the samples at room temperature for 1 h or at 0°C for 3 h, with subsequent short‐term heating to 45°C, caused an almost equal rise in Ts throughout the collagen sheets. We conclude that a homogeneous fixation is obtained by the combination of presoaking at low temperature, followed by short‐term microwave irradiation to 45°C.
Use of microwaves for rapid fixation of tissues in vivo
Authors: Stavinoha William B.
Published: April 2013

Accurate knowledge of the concentration in the central nervous system of neurochemicals undergoing rapid enzymatic destruction or synthesis is sparse because of the difficulty in stopping the rapid reactions while causing only minimal adverse changes in the neurochemistry and structure. Microwave heating can be effectively used to rapidly stop enzyme activity in the central nervous system with minimal adverse changes. This rapid inactivation of the enzymes increases the validity of the sample that is taken for analysis of the concentration of the enzyme's substrate.
Identifying Influential Factors of Knowledge Sharing in Emergency Events: A Virtual Community Perspective
Authors: Shan Siqing , Xin Tenglong , Wang Li , Li You , Li Ling
Published: April 2013

Knowledge sharing on emergency events in virtual communities is a significant information source for emergency management. Based on social cognitive theory and social capital theory as well as the consideration of the characteristics of emergency events, we employ a survey questionnaire for the empirical study and adopt the two‐stage confirmatory factor analysis method to construct a structural equation model for identifying the influential factors in knowledge sharing in emergencies. Through conducting a detailed data analysis, our study reveals that that some emergency event characteristics have significant effects on both the quality and quantity of knowledge sharing. Copyright © 2013 John Wiley & Sons, Ltd.
Fast SVM training using edge detection on very large datasets
Authors: Li Boyang , Wang Qiangwei , Hu Jinglu
Published: April 2013

In a standard support vector machine (SVM), the training process has O(n3) time and O(n2) space complexities, where n is the size of the training dataset. For very large datasets, it is thus computationally infeasible. Reducing the size of training dataset is naturally considered as a method to solve this problem. SVM classifiers are constructed by using the training samples called support vectors (SVs) that lie close to the separation boundary. Thus, removing the other samples that are not relevant to SVs might have no effect on building the separation boundary. In other words, we need to reserve the samples that are likely to be SVs. Therefore, a method based on edge detection techniques is proposed to extract such samples near the separation boundary. In order to avoid overfitting, we also use a clustering algorithm to keep the distribution properties of the training dataset. The samples selected by the edge detector and the centroids of clusters are used to reconstruct the training dataset. In the proposed approach, the edge detection technique helps us to extract the local properties around the separation boundary and the clustering algorithm preserves the properties of the entire data. The reconstructed training dataset with a smaller number of samples can make the training process very fast without degrading the classification accuracy. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Sputtering condition optimization of sputtered IrOx and TiN stimulus electrodes for retinal prosthesis
Authors: Pan Yi‐Li , Noda Toshihiko , Sasagawa Kiyotaka , Tokuda Takashi , Ohta Jun
Published: April 2013

We have optimized the sputtering conditions for sputtered IrOx and TiN electrodes for retinal prosthesis. The basic electrochemical characteristics were evaluated by cyclic voltammetry, and the surface morphology was inspected by atomic force microscopy. To measure the charge delivery capacity (CDC), a 300‐µm diameter electrode was formed, a balanced biphasic current pulse was applied, and the voltage response was measured. From the experimental results, the CDCs of IrOx and TiN in the best sputtering conditions were improved by more than 8 and 4 times compared to that of Pt, respectively. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Repeat measurements of nuchal translucency at 11–14 weeks of gestation: when do we need them?
Authors: Salomon L. J. , Porcher R. , Socolov D. , Lamrani H. , Ville Y.
Published: April 2013

Objective

Previous studies have recommended that several repeat measurements of nuchal translucency (NT) be obtained to optimize sensitivity of the screening process. However, truncation is applied within the risk calculation for small NT measurements; therefore, repeating NT measurements in the lower range may be unnecessary. The aim of this study was to determine the optimal number of NT measurements and whether this is dependent on the initial value obtained.

Methods

We simulated the expected distribution of sets of five repeat NT measurements and their corresponding likelihood ratios (LR) for a variety of crown–rump length (CRL) values at 11–14 weeks' gestation, based on the published mixture model for first‐trimester NT measurements and on published data regarding NT measurement variability. The ratio between LR obtained from the highest and the initial measurement in each set were computed, with a ratio of 1 indicating that repeat measurements would have no effect on risk estimation. We calculated NT cut‐offs below which a change in estimated LR would occur in fewer than 10% of cases if repeat measurements were obtained, and we tested this approach on a real first‐trimester screening dataset.

Results

The simulations performed indicated that repeating NT measurements when the first NT obtained ranged between ≤ 0.9 and ≤ 1.6 mm at CRLs of 45 and 84 mm, respectively, is not useful. When applied to a real dataset, our approach allowed avoiding repetition of measurements in 47/165 cases (28%).

Conclusions

Although there is some variability in NT measurements, repeat assessment is not useful to optimize screening performance for the smallest NT measurements due to lower truncation limits that are applied in risk calculation. Our study provides NT cut‐off values, in relation to CRL, below which it appears that there is no need to repeat measurements once a good quality image has been obtained. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Intermediate temperature proton‐conducting membrane electrolytes for fuel cells
Authors: Scott Keith , Xu Chenxi , Wu Xu
Published: April 2013

This review provides an overview of intermediate temperature proton‐conducting membrane electrolyte materials for fuel cells. Such fuel cells operate in the approximate temperature range of 150–300°C and can capitalize on a number of technological reasons for operating H2/air. These reasons include enhancement of electrochemical kinetics, simplified water management, efficient cooling, and useful waste heat recovery. Importantly lower quality, for example, reformed hydrogen, containing relatively large amounts of carbon dioxide, may be used as the fuel. The materials, which have been the focus of intermediate temperature proton‐conducting fuel cells, include heteropolyacids, metal pyrophosphates, solid acids, and acid‐imbibed high‐temperature polymers such as polybenzimidazole. WIREs Energy Environ 2014, 3:24–41. doi: 10.1002/wene.64

This article is categorized under:

Fuel Cells and Hydrogen > Science and Materials
Overexpression of ctr1Δ300, a high‐affinity copper transporter with deletion of the cytosolic C‐terminus in Saccharomyces cerevisiae under excess copper, leads to disruption of transition metal homeostasis and transcriptional remodelling of cellular processes
Authors: Schuller Astrid , Auffermann Gudrun , Zoschke Katja , Schmidt Ulrike , Ostermann Kai , Rödel Gerhard
Published: April 2013

In an approach to generating Saccharomyces cerevisiae strains with increased intracellular copper amounts for technical applications, we overexpressed the copper transporter CTR1 and a variant of CTR1 with a truncation in the C‐terminus after the 300th amino acid (ctr1Δ300). We determined the copper sensitivity of the generated strains and used inductively coupled plasma spectrometry analysis (ICP–OES and ICP–MS) to investigate the effects of overexpression of both constructs under excess copper on the cellular content of different elements in S. cerevisiae. In addition, we performed DNA microarray analysis to obtain the gene expression profile under the changed element contents. Overexpression of CTR1 increased the copper content in the cells to 160% and 78 genes were differentially regulated. Overexpression of the truncated ctr1Δ300 resulted in an increased copper, iron and zinc content of > 200% and 980 genes showed differential expression. We found that transition metal ion homeostasis was disrupted in ctr1Δ300‐overexpressing strains under excess copper and that this was combined with a transcriptional remodelling of cellular processes. Copyright © 2013 John Wiley & Sons, Ltd.
Examining the Antecedents of U.S. Nonmarital Fatherhood
Authors: Carlson Marcia J. , VanOrman Alicia G. , Pilkauskas Natasha V.
Published: April 2013

Despite the dramatic rise in U.S. nonmarital childbearing in recent decades, limited attention has been paid to factors affecting nonmarital fatherhood (beyond studies of young fathers). In this article, we use data from the 2002 National Survey of Family Growth and the National Longitudinal Survey of Youth 1979 cohort to examine the antecedents of nonmarital fatherhood, as compared to marital fatherhood. Overall, we find the strongest support across both data sets for education and race/ethnicity as key predictors of having a nonmarital first birth, consistent with prior literature about women’s nonmarital childbearing and about men’s early/teenage fatherhood. Education is inversely related to the risk of nonmarital fatherhood, and minority (especially black) men are much more likely to have a child outside of marriage than white men. We find little evidence that employment predicts nonmarital fertility, although it does strongly (and positively) predict marital fertility. High predicted earnings are also associated with a greater likelihood of marital childbearing but with a lower likelihood of nonmarital childbearing. Given the socioeconomic disadvantage associated with nonmarital fatherhood, this research suggests that nonmarital fatherhood may be an important aspect of growing U.S. inequality and stratification both within and across generations.
Socio-Economic and Political Motivations of Russian Out-Migration from Central Asia
Authors: Bandey Aijaz A. , Rather Farooq Ahmad
Published: April 2013

The unexpected fall of Soviet Union left ethnic Russians, outside Russia with many questions and concerns. Many of them emigrated to Russia from the erstwhile Soviet Union, for better conditions there. The disintegration of Soviet Union – a state created on the ideology of Communism was one of the reasons, apart from economic, political, socio-cultural, reasons besides the failure of Communism to keep the Soviet Union together were the main causes of Russian out-migration from Central Asia. The out-migration of Russians from Central Asia to Russia began in the 1970s as internal labour migration shifted in the wake of better job opportunities. It accelerated tremendously after 1991, and touched its highest mark in 1994, as a response to the relative economic prosperity of Russia at that time. Thus the improved standard of living in Russia and the desire to return to their cultural homeland were some major issues that concerned people to shift to Russia.
Levels of supramolecular chirality of polyglutamine aggregates revealed by vibrational circular dichroism
Authors: Kurouski Dmitry , Kar Karunakar , Wetzel Ronald , Dukor Rina K. , Lednev Igor K. , Nafie Laurence A.
Published: April 2013

Polyglutamine (PolyQ) aggregates are a hallmark of several severe neurodegenerative diseases, expanded CAG‐repeat diseases in which inheritance of an expanded polyQ sequence above a pathological threshold is associated with a high risk of disease. Application of vibrational circular dichroism (VCD) reveals that these PolyQ fibril aggregates exhibit a chiral supramolecular organization that is distinct from the supramolecular organization of previously observed amyloid fibrils. PolyQ fibrils grown from monomers with Q repeats 35 and above (Q
⩾ 35) exhibit approximately 10‐fold enhancement of the same VCD spectrum compared to the already enhanced VCD of fibrils formed from Q repeats 30 and below (Q
⩽ 30).