bluuebunny/crossref_metadata_2025 huggingface dataset:
Deuterium kinetic isotope effects and H/D exchange in dimerization of acetylene with a Nieuwland catalyst in aqueous media
Authors: Tachiyama Takashi , Yoshida Makoto , Aoyagi Tatsuhiro , Fukuzumi Shunichi
Published: May 2008

Deuterium kinetic isotope effects were observed in the dimerization of acetylene with a Nieuwland catalyst in an aqueous media, where the copper–acetylene and copper–monovinylacetylene (MVA) π‐complexes were detected as intermediates by 1H NMR. The copper–acetylene π‐complex is responsible for an efficient H/D exchange between acetylene and proton (or deuteron) of water, which occurs rapidly with a Nieuwland catalyst. The deuterium kinetic isotope effects and the rapid H/D exchange reaction together with the detection of the copper–acetylene and copper–MVA π‐complexes provide deeper insight into the catalytic mechanism of the Nieuwland catalysis for the dimerization of acetylene. Copyright © 2008 John Wiley & Sons, Ltd.
Electrochemical glycosylation in the presence of a catalytic chemical mediator
Authors: Drouin Ludovic , Compton Richard G. , Fairbanks Antony J.
Published: May 2008

Electrochemical glycosylation of thioglycoside donors proceeds efficiently in an undivided cell in the presence of a catalytic amount of the chemical mediator (4‐bromophenyl) ammoniumyl hexachloroantimonate (BAHA). In comparison with electrochemical glycosylation alone, the use of a catalytic amount of BAHA greatly increases the rate of reaction, reduces the potential required and inhibits ester‐protecting group migrations. Copyright © 2008 John Wiley & Sons, Ltd.
Optimal irradiation wavelength in iniferter‐based photocontrolled radical polymerization
Authors: Nemoto Y. , Nakayama Y.
Published: May 2008

In iniferter‐based photocontrolled radical polymerization optimal irradiation wavelength was examined for precise molecular design of star vectors, which can function as high‐performance gene carriers. Monochromatic light in the range from 330 to 400 nm with the interval of about 10 nm was irradiated to tetrafunctional iniferter, 1,2,4,5‐tetrakis(N,N‐diethyldithiocarbamylmethyl)benzene, in the presence of N,N‐dimethyaminopropylacrylamide (DMAPAAm), as a model monomer, in toluene. In all wavelengths tetrabranched polymers were produced except for 400‐nm‐irradiation. The highest conversion reaching to about 35% was observed at the wavelength of 370 nm after only 40 min of irradiation. There was no further increase in conversion by combination with another two wavelengths. HPLC analysis and NMR spectra showed that the polymerization at the optimal wavelength of 370 nm was occurred in a living manner with the ability to control the chain length (from about 5000 to 40,000) having very narrow polydispersity (about 1.6) by changing of the irradiation time, the intensity, and the monomer concentration. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4505–4512, 2008
Tris[tri(2‐thienyl)phosphine]palladium as the catalyst precursor for thiophene‐based Suzuki‐Miyaura crosscoupling and polycondensation
Authors: Li Weiwei , Han Yang , Li Binsong , Liu Caiming , Bo Zhishan
Published: May 2008

Zero‐valent palladium complex, Pd(PTh3)3, with three tri(2‐thienyl)phosphine ligands was prepared and characterized. Pd(PTh3)3 is superior to Pd(PPh3)4 in catalyzing Suzuki‐Miyaura coupling and polymerization of thiophene‐based derivatives. The Suzuki polycondensation of 3‐hexyl‐5‐iodothiophene‐2‐boronic pinacol ester with Pd(PTh3)3 as the catalyst precursor afforded high‐molecular‐weight P3HT with high regularity and yield. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4556–4563, 2008
Synthesis and encapsulation properties of dendronized polymer with Fréchet‐type dendrons peripherally decorated by carboxylic acid functionalization
Authors: Jiao Qing , Yi Zhuo , Chen Yongming , Xi Fu
Published: May 2008

A new carboxylic acid‐terminated dendronized polymer (denpol), constructed with linear chain attaching Fréchet‐type dendrons at each repeat unit, has been designed and synthesized through a combination of macromonomer route and hydrolysis reaction. The resulting denpol exhibits excellent solubility in aqueous solution for pH ≥ 6, and significantly the denpol also encapsulates various aromatic molecules efficiently. The results of UV–vis and fluorescence spectra indicate that hydrophobic and π‐π interactions bring into effect between the water‐insoluble organic molecules and the denpol. Moreover, the photoisomerization of azobenzene solubilized in denpol aqueous solution was investigated, which indicated that trans‐to‐cis and cis‐to‐trans conversions were first‐order reactions. The enhancement of photoisomerization property may attribute to the proper microenvironment in the denpol. Therefore, the denpol is expected to be a potential candidate as amphiphilic unimolecular container. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4564–4574, 2008
Photophysical and self‐assembly behavior of poly(amidoamine) dendrons with chromophore as scaffold: The effect of dendritic architecture
Authors: Wang Bing‐Bing , Li Wu‐Song , Jia Xin‐Ru , Gao Min , Jiang Lei , Wei Yen
Published: May 2008

Two series of amphiphiles composed of hydrophilic poly(amidoamine) dendrons (from the first to the third generation) as the shell and hydrophobic aromatic chromophores (3,6‐di(maleimidyl)‐9‐phenyl carbazole and 9‐(4′‐maleimidyl phenyl)‐3‐maleimidyl carbazole) as the central scaffold were synthesized. The effect of dendritic architecture on the photophysical properties and the self‐assembly behavior of these amphiphiles were studied by UV–vis absorption spectroscopy, fluorescence spectroscopy, and transmission electron microscopy (TEM) measurements. Both the generation of dendritic shell and the location of dendrons at the chromophoric scaffold had great effect on the photophysical properties of these amphiphiles. In addition, different spherical aggregates were formed from these amphiphiles in the aqueous solution at different concentrations. Because of the combined effects of steric hindrance and architecture of dendritic shells, the amphiphiles from G2 dendron with central chromophore self‐organized into ordered aggregates more readily than that from G1 and G3. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4584–4593, 2008
Controlled/living radical polymerization of vinylcyclicsilazane by RAFT process and their block copolymers
Authors: Nghiem Quoc Dat , Nguyen Chi Thanh , Kim Dong‐Pyo
Published: May 2008

High molecular weight poly(vinyl)silazane were synthesized successfully by reversible addition fragmentation chain transfer (RAFT) polymerization in toluene at 120 °C, using dithiocarbamate derivatives and 2,2′‐azobis‐isobutyrylnitrile (AIBN) as the RAFT agents and thermal initiator, respectively. The polymerization of a vinylcyclicsilazane oligomer with 82.5% conversion was readily controlled to increase the molecular weight from 1000 to 12,000 g/mol with a narrow polydispersity <1.5. The resulting polymer showed a high ceramic yield of 70 wt % at 1000 °C. Moreover, the approach was extended successfully to the synthesis of poly(vinyl)silazane‐block‐polystyrene as an inorganic–organic diblock copolymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4594–4601, 2008
Remote sensing of permafrost‐related problems and hazards
Authors: Kääb Andreas
Published: May 2008

Modern remote sensing techniques can help in the assessment of permafrost hazards in high latitudes and cold mountains. Hazard development in these areas is affected by process interactions and chain reactions, the ongoing shift of cryospheric hazard zones due to atmospheric warming, the large spatial scales involved and the remoteness of many permafrost‐related threats. This paper reviews ground‐based, airborne and spaceborne remote sensing methods suitable for permafrost hazard assessment and management. A wide range of image classification and change detection techniques support permafrost hazard studies. Digital terrain models (DTMs) derived from optical stereo, synthetic aperture radar (SAR) or laser scanning data are some of the most important data sets for investigating permafrost‐related mass movements, thaw and heave processes, and hydrological hazards. Multi‐temporal optical or SAR data are used to derive surface displacements on creeping and unstable frozen slopes. Combining DTMs with results from spectral image classification, and with multi‐temporal data from change detection and displacement measurements significantly improves the detection of hazard potential. Copyright © 2008 John Wiley & Sons, Ltd.
Polysomnographic values in adolescents with ataxia telangiectasia
Authors: McGrath‐Morrow Sharon A. , Sterni Laura , McGinley Brian , Lefton‐Greif Maureen A. , Rosquist Karen , Lederman Howard
Published: May 2008

Most adolescents with ataxia telangiectasia (A‐T) develop progressive bulbar muscle weakness and decreased pulmonary reserve. The purpose of this study was to define the patterns of sleep and respiration during sleep, and to identify sleep‐related breathing problems in subjects with A‐T. To address these issues, overnight polysomnography was performed on 12 adolescents with A‐T. Eleven of the 12 subjects completed overnight polysomnography. The median age was 16 years (range, 13–20 years). All subjects in the study were wheelchair‐bound and the median forced vital capacity (% predicted of normal) was 44% (range, 16–82%). The mean sleep efficiency was 72.6% with a mean apnea hypopnea index (AHI) of 0.7 events/hr (range, 0–2.2). The majority of apnea/hypopneas were REM related. The mean central apnea index was 0.1 events/hr (range, 0–0.2). The mean oxygen saturation nadir was 92.7% (range, 87–96) and the mean peak end‐tidal carbon dioxide ET value was 53.8 mm Hg (range, 49–60). Two of 11 subjects had ET values ≥50 mm Hg for more than 50% of total sleep time. In this study, the majority of A‐T adolescents had infrequent partial or complete upper airway obstructions during sleep and minimal nighttime hypoxemia. They did, however, have decreased sleep efficiency most likely, due in part, to their underlying neurological condition. This decrease in total sleep time may underestimate hypoventilation. Based on these findings, overnight polysomnography should be considered in adolescents with A‐T, particularly in those in which there is a clinical suspicion of sleep related breathing abnormalities. Pediatr Pulmonol. 2008; 43:674–679. © 2008 Wiley‐Liss, Inc.
Predicting helix orientation for coiled‐coil dimers
Authors: Apgar James R. , Gutwin Karl N. , Keating Amy E.
Published: May 2008

The α‐helical coiled coil is a structurally simple protein oligomerization or interaction motif consisting of two or more alpha helices twisted into a supercoiled bundle. Coiled coils can differ in their stoichiometry, helix orientation, and axial alignment. Because of the near degeneracy of many of these variants, coiled coils pose a challenge to fold recognition methods for structure prediction. Whereas distinctions between some protein folds can be discriminated on the basis of hydrophobic/polar patterning or secondary structure propensities, the sequence differences that encode important details of coiled‐coil structure can be subtle. This is emblematic of a larger problem in the field of protein structure and interaction prediction: that of establishing specificity between closely similar structures. We tested the behavior of different computational models on the problem of recognizing the correct orientation—parallel vs. antiparallel—of pairs of alpha helices that can form a dimeric coiled coil. For each of 131 examples of known structure, we constructed a large number of both parallel and antiparallel structural models and used these to assess the ability of five energy functions to recognize the correct fold. We also developed and tested three sequence‐based approaches that make use of varying degrees of implicit structural information. The best structural methods performed similarly to the best sequence methods, correctly categorizing ∼81% of dimers. Steric compatibility with the fold was important for some coiled coils we investigated. For many examples, the correct orientation was determined by smaller energy differences between parallel and antiparallel structures distributed over many residues and energy components. Prediction methods that used structure but incorporated varying approximations and assumptions showed quite different behaviors when used to investigate energetic contributions to orientation preference. Sequence based methods were sensitive to the choice of residue‐pair interactions scored. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Early stages of decomposition in Al alloys investigated by X‐ray absorption
Authors: Klobes B. , Staab T. E. M. , Dudzik E.
Published: May 2008

We demonstrate the sensitivity of X‐ray absorption fine‐structure (XAFS) measurements to the earliest stages of decomposition in Al alloys, i.e. just a few minutes after quenching. XAFS is one of the few applicable experimental approaches to this regime. Three different AlCu(Mg) samples were investigated by XAFS at the Cu K edge. Significant changes of the XAFS can be detected in the course of the decomposition in these alloys during the first 15 minutes. Actually, these changes correspond to relaxations of the nearest neighbours towards the absorbing Cu atoms. The Fourier transformation of the XAFS spectra thus leads to a pseudo radial distribution function which reflects this relaxation. In addition, XAFS measurements of the S‐phase of AlCuMg are used to decide in favour of the Perlitz and Westgren model for the S‐phase. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of second‐order orbital‐dependent DFT correlation functionals
Authors: Grabowski Ireneusz
Published: May 2008

The choice of the orbital‐dependent second‐order correlation functional plays the prime role in the description of the correlation effects in orbital‐dependent DFT calculations. Using second‐order perturbation theory we were able to derive the simplest orbital‐dependent correlation functional, but even at this lowest correlation level, we had several possibilities to define it. Applications of different second‐order correlation functionals for the atomic as well as molecular systems are presented. The ab initio DFT‐type OEP2 functionals based on Møller‐Plesset or semicanonical partitioning (OEP2‐sc) are compared with those based on Epstein‐Nesbet type partitioning, showing that the latter ones can fail in more difficult molecular problems, e.g., the Be dimer potential curve. We show that currently the best performing orbital‐dependent second‐order correlation functional is the OEP2‐sc one. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Noniterative corrections to equation‐of‐motion coupled‐cluster excited state energies based on the reduced method of moments of coupled cluster equations
Authors: Kowalski Karol , Marat Valiev
Published: May 2008

A new formalism closely related to the Method of Moments of Coupled‐Cluster equations (MMCC) is obtained by embedding approximate coupled cluster (CC) or equation‐of‐motion CC (EOMCC) formalism into a formalism which uses cluster or excitation operators defined by excitation operators of higher rank with respect to a given approximation. Noniterative corrections akin to completely renormalized EOM‐CCSD(T) corrections reveal structural similarities to the CCSD(T) corrections for the ground state. Several benchmark calculations on the O3 and Cl2O molecules are discussed to illustrate the performance of this approach. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
All‐electron all‐virtual spinor space relativistic coupled‐cluster calculations for molecules of heavy elements using contracted basis set: Prediction of atomization energy of PbH4*
Authors: Malli Gulzari L. , Siegert Martin , Turner David P.
Published: May 2008

All‐electron all‐virtual spinor space (AVSS) relativistic second order Møller–Plesset (RMP2), coupled‐cluster singles doubles (RCCSD), RCCSD(T) (RCCSD plus the triple excitation correction included perturbationally) calculations are reported for tetrahedral (Td) PbH4 at various bond lengths using our finite contracted universal Gaussian basis set. Our relativistic calculations predict the RMP2, RCCSD, and RCCD(T) molecular correlation energy for PbH4 as −2.2563, −2.1917, and −2.2311 au, respectively. Ours are the first AVSS RMP2, RCCSD, and RCCSD(T) molecular calculations for electron correlation energy of the heavy element molecule PbH4. All‐electron AVSS coupled‐cluster calculations for the Pb atom are also reported and these were used (in conjunction with the corresponding molecular electron correlation energy calculations for PbH4) to predict atomization energy (Ae) of PbH4 at various levels of coupled‐cluster electron correlation. Our predicted atomization energy for PbH4 (at the optimized bond length of 1.749 Å) with our Dirac–Fock, RMP2, RCCSD, and RCCSD(T) calculations is 5.73, 7.27, 11.24, and 11.62 eV, respectively. Neither such relativistic molecular correlation energy nor atomization energy has been reported so far for heavy polyatomic with 86 electrons. Calculation of relativistic molecular correlation energy is no more a nightmare, and bottlenecks are broken for the calculation of relativistic correlation as well as atomization energy for molecules of heavy elements. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Accurate Born–Oppenheimer calculations of the low‐lying c3Σ and a3Σ excited states of helium dimer
Authors: Pavanello Michele , Cafiero Mauricio , Bubin Sergiy , Adamowicz Ludwik
Published: May 2008

Accurate variational Born–Oppenheimer calculations of the two lowest excited Σ triplet states of the helium dimer at their respective equilibrium geometries are reported. The wave functions of the states are expanded in terms of explicitly correlated Gaussian functions with shifted centers. The obtained energies are the best variational estimates ever calculated for these states. One‐electron densities are also presented and discussed. The results are compared with the experimental values and previous calculations. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Detecting biological responses to flow management: missed opportunities; future directions
Authors: Souchon Yves , Sabaton Catherine , Deibel Robert , Reiser Dudley , Kershner Jeffrey , Gard Mark , Katopodis Christos , Leonard Paul , Poff N. Leroy , Miller William J. , Lamb Berton Lee
Published: May 2008

The conclusions of numerous stream restoration assessments all around the world are extremely clear and convergent: there has been insufficient appropriate monitoring to improve general knowledge and expertise. In the specialized field of instream flow alterations, we consider that there are several opportunities comparable to full‐size experiments. Hundreds of water management decisions related to instream flow releases have been made by government agencies, native peoples, and non‐governmental organizations around the world. These decisions are based on different methods and assumptions and many flow regimes have been adopted by formal or informal rules and regulations. Although, there have been significant advances in analytical capabilities, there has been very little validation monitoring of actual outcomes or research related to the response of aquatic dependent species to new flow regimes. In order to be able to detect these kinds of responses and to better guide decision, a general design template is proposed. The main steps of this template are described and discussed, in terms of objectives, hypotheses, variables, time scale, data management, and information, in the spirit of adaptive management. The adoption of such a framework is not always easy, due to differing interests of actors for the results, regarding the duration of monitoring, nature of funding and differential timetables between facilities managers and technicians. Nevertheless, implementation of such a framework could help researchers and practitioners to coordinate and federate their efforts to improve the general knowledge of the links between the habitat dynamics and biological aquatic responses. Copyright © 2008 John Wiley & Sons, Ltd.
Growth and voltinism in the aquatic insects of a regulated river subject to groundwater inflows
Authors: Fjellheim Arne , Raddum Gunnar G.
Published: May 2008

The water temperature and discharge of the Vassbygdelvi River, Aurland watershed, was altered after regulation due to transfer of cold water from the higher parts of the catchment. The lower part of the river receives a considerable amount of groundwater, which affected the water temperature due to reduced discharge. Compared to a closely situated reference station, the temperature increased by 9% on a yearly basis. The temperature differences were most pronounced during the winter when average January water temperature at the reference and the stretch influenced by groundwater was 0.8 and 3.3°C, respectively. Studies of benthic insects in the two habitats showed that the temperature differences had little effect on the length of the life cycle. Although some species show significant differences in growth pattern during parts of the year, with more rapid development in the winter‐warm locality, there was a trend for synchronous growth at both localities. Compared to the situation before regulation, two species of stoneflies became extinct and one mayfly species colonized the area, probably as a result of the increased number of annual degree‐days. Copyright © 2008 John Wiley & Sons, Ltd.
Changes in macroalgae and bottom fauna in the winter period in the regulated Alta River in Northern Norway
Authors: Koksvik Jan Ivar , Reinertsen Helge
Published: May 2008

The study was carried out in the upper part of the Alta River (69°58N; 23°24E), on a 3 km stretch that is not covered by ice due to increased winter temperatures after hydroelectric power development in 1987. The aim was to detect potential effects on the macroalgae and bottom fauna from the altered physical conditions. The presented data, based on Surber samples, describe the late winter situation (March to May) for the macroalgae (1996–2004) and the bottom fauna (1993–2004). The maximum biomasses of algae showed a highly significant decline from close to 200 g dry weight (ash free) m−2 in 1996 to less than 50 g dry weight m−2 in the last years of the investigation. Microspora amoena was the overall dominating species in the first phase of the study and Didymosphenia geminata in the last 5 years. Ulothrix zonata and Hydrurus foetidus were common throughout the entire study. A highly significant linear decline (r2 = 0.752, p = 0.001) was found in the total bottom fauna densities, showing means from 9500 to 16 000 ind. m−2 in 1993–1996 and from 2200 to 2700 ind. m−2 in 2001–2004. The reduction primarily concerned Chironomidae larvae. The mean biomass of the bottom fauna did not change to the same extent due to low individual weight of the Chironomidae larvae. A strong correlation between algal biomass and bottom fauna density was found (r2 = 0.796, p = 0.0029). The study demonstrates a eutrophication effect in the ice‐free river section following the regulation. The effect decreased through the investigated period and terminated 13–15 years after the regulation took place. Copyright © 2008 John Wiley & Sons, Ltd.
Response of migrating chinook salmon (ONCORHYNCHUS TSHAWYTSCHA) smolts to in‐stream structure associated with culverts
Authors: Kemp Paul S. , Williams John G.
Published: May 2008

Poorly designed culverts can impede upstream movements of fish under high flows when excessive water velocities create adverse conditions. Improvement in upstream fish passage efficiency may occur with placement of structures within culverts that increase hydraulic complexity and provide resting areas. The effects of structural modification on downstream migrants, however, are unknown. To address this gap in knowledge, the behaviour of Chinook salmon (Oncorhynchus tshawytscha) smolts was assessed in an experimental laboratory flume. Under light and dark conditions, fish were observed as they encountered either an unmodified aluminium channel (control) or one of two treatments: an ‘intermediate’ substrate (treatment channel lined with corrugated sheet) or a ‘complex’ substrate (addition of cobbles to the ‘intermediate’ treatment). More smolts passed the control channel than the treatment channels. Even with control of the variation in flow between channels, under light conditions more fish than expected passed the control channel when paired with the complex treatment. Smolts more frequently rejected both treatments than the control channel when light, and the complex treatment when dark, by swimming upstream against the flow after entry. The majority of fish moved through the flume facing downstream, although a greater proportion faced upstream when dark than when light, and entered the control channel. Velocity of downstream movement (ground velocity) was greater through the control channel than for the treatment routes, and slower than the mean water velocity, and under the dark condition. When mean water velocities were taken into account, the net velocity through the control channel was not significantly different to the intermediate, and lower than the complex channel. Juvenile Chinook salmon determined fine‐scale variation in structural complexity and exhibited avoidance behaviour in the presence and absence of visual stimuli. Hydraulic stimuli influenced route selection exhibited by migratory juvenile salmonids. Copyright © 2008 John Wiley & Sons, Ltd.
Overwintering and downstream migration of sea trout (Salmo truttaL.) kelts under regulated flows—northern Sweden
Authors: Östergren Johan , Rivinoja Peter
Published: May 2008

Post‐spawning migrations of sea trout (Salmo truttaL.) in two northern Swedish river systems, Vindelälven and Piteälven, were studied. Telemetry was used to evaluate spawning locations, post‐spawning mortality, overwintering survival/habitat selection/location, partitioned natural mortality from dam passage mortality and overall survival from post‐spawning to the sea entry. Fifty‐eight sea trout (LT = 50–86 cm) were radio‐tagged at the beginning of their spawning migration from June to September in 2003 and 2004, and their spawning in September and October each year was monitored. In total, 91% (n = 53) survived spawning and were thus defined as kelts. Of these, 92% (n = 49) overwintered under ice‐cover in deep, slow flowing sections of the rivers. Overwintering mortality was low, on average 8%. The main seaward migration occurred during May and June and was initiated when ambient water temperatures exceeded 4–6°C, independent of the start of the spring flood when flows rose to 1000 m3 s−1. The highest downstream migration speed was approximately 25 km 24 h−1and migrations mainly took place at daytime. During seaward migration, the kelts encountered hydropower stations that lacked bypass systems for fish passage, which delayed their downstream migrations. Passage mortality at the power stations was 69 and 25% in the Vindelälven and Piteälven, respectively. These losses, combined with the naturally high winter survivals of kelts at the unregulated river parts, underline the importance of developing safe passage routes for kelts at hydropower facilities for conserving sea trout populations in regulated rivers. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of hydrological regimes on the pre‐spawning entry of Atlantic salmon (Salmo salar L.) into an upland river
Authors: Tetzlaff D. , Gibbins C. , Bacon P. J. , Youngson A. F. , Soulsby C.
Published: May 2008

The Girnock Burn is an Atlantic salmon (Salmo salar) spawning tributary of the river Dee, Aberdeenshire, Scotland. The dates, sexes and numbers of adult salmon entering the stream in the three months prior to spawning were determined between 1969 and 2005 using a permanent fish‐trap. During this time, the number of fish returning to spawn varied markedly. Here we analyze the whole of this unique long term data set in order to characterize and classify the hydrologic regimes of the pre‐spawning migration period and assess the extent to which these regimes help explain the timing and patterns of arrival of adult salmon into the stream. A range of flow parameters was calculated for the arrival period (September–November) for each of the 37 years. These parameters were used to ordinate and classify years according to their flow regimes. The analysis yielded six distinct groups or ‘flow regime types’ which separated principally in relation to flow magnitude and frequency parameters. The number of fish entering the burn on a given day was not significantly correlated to discharge on that day. However, patterns of arrival of fish differed markedly between years with different regime types, with the number of fish arriving on a given day related to patterns of discharge over the preceding part of the arrival period. Overall inter‐annual variability in entry corresponded to the defined regime types. In wetter years, fish entry to the stream usually starts relatively early and continues throughout the pre‐spawning period. In contrast, dry years may result in fish entry being delayed; this may result in lower numbers of spawning females entering the stream and sub‐optimal utilization of juvenile habitat in the following spring. Copyright © 2008 John Wiley & Sons, Ltd.
Field study of an attraction channel as entrance to fishways
Authors: Lindmark Elianne , Gustavsson L. Håkan
Published: May 2008

A flow device that accelerates turbine tail water (or any free stream) to act as an attraction for migrating fish is field tested. The device consists of an open (U‐shaped) channel which accelerates the incoming flow by a local constriction of the cross‐sectional area. The velocity increase has previously been investigated in a lab‐scale model and an increase of 38% has been established. In the summers of 2004 and 2005, a full‐scale prototype of the attraction channel was tested at the Sikfors hydropower plant in the Pite River in Sweden. The channel was equipped with underwater cameras to monitor and record the fish swimming through it. The tests show that the fish do swim through the attraction channel. During the same time period in 2004 and 2005, 57 and 471 fishes swam through the channel, respectively. The major change of the channel between the two years was that it was painted black for 2005. Copyright © 2008 John Wiley & Sons, Ltd.
Random displacement versus habitat choice of fish larvae in rivers
Authors: Wolter Christian , Sukhodolov Alexander
Published: May 2008

Numerous studies elaborated habitat preferences of early juvenile fish. However, detailed analyses of swimming performance of fish larvae and early juveniles revealed substantial doubts about their ability to maintain positions in the river and to choose habitats. It was hypothesized that the juveniles will be randomly distributed by turbulent flows initially, and that the match with suitable nurseries depends on the shore line heterogeneity. Low swimming performance of juvenile fish, as compared to the flow velocities in rivers, allows consideration of a longitudinal dispersion model as a tool to predict the spatio‐temporal patterns of juvenile fish assemblages, e.g. downstream of a spawning site. Because of variable geometry of the river channel, longitudinal dispersion should be expanded with equations describing the effect of stagnant flow zones which can also act as the refuge. In this study a model of dispersion processes with non‐transit zones was developed and validated for the lowland Müggelspree River, Germany. Computations with the model provide the possibility to explore the effect of flow and channel geometry on the distribution history of juvenile fish. Particularly, the model allows in a probabilistic way to estimate for the portion of juvenile fish retained in non‐transit zones of the flow and subsequently of the portion transported downstream to the lakes, and thus, finally, to assess the importance of random displacement for the spatial structure of the juvenile fish assemblage in a river. Copyright © 2008 John Wiley & Sons, Ltd.
The role of seedbanks in restoration of floodplain woodlands
Authors: Jensen Anne E. , Walker Keith F. , Paton David C.
Published: May 2008

Plant communities on the River Murray floodplain, South Australia, are degraded by flow regulation and salinization, with up to 95% of eucalypt trees being dead or dying from water stress. This paper describes the floodplain seed bank and its capacity to respond to floods or managed ‘environmental flows’. The soil seed bank contained mainly annual native species, particularly chenopods, whereas the dominant trees, river red gum and black box (Myrtaceae: Eucalyptus camaldulensis, E. largiflorens), retained most of their seeds in a canopy seed bank (‘serotiny’). In healthy trees, seed release peaked in summer (December– February for river red gum, October–March for black box), but variable volumes suggested cyclical patterns in seed crops. Seed release, viability and germination rates did not appear to limit recruitment. In water‐stressed trees, however, seed release was up to nine‐fold less. Germination requires water from floods or local rainfall. Flow regulation has reduced flood frequencies and delayed timing, so that germination now is likely to be followed by relatively hot, dry conditions (summer). Following managed watering events, seeds accumulated in high‐water strandlines, where they germinated readily under a mulch of organic litter, but survival was limited. The importance of local rainfall as a complementary water source was demonstrated, and survival rates were higher for rain‐triggered germinants, compared to seedlings germinating in strandlines created by managed watering. Seedling survival would be greater if environmental flows were delivered to complement local rainfall or to extend the effect of short flood events. Copyright © 2008 John Wiley & Sons, Ltd.
Measurement of force components for ink detachment of newsprints
Authors: Pan Jolly , Nguyen Kien L.
Published: May 2008

Ink detachment tests were carried out using a Couette device. During the test, the energy supplied to the operation of the device partially dissipated as heat. The fraction of energy dissipated increased with pulp consistency. The fraction of energy for peeling and pulling the ink from the printed samples were calculated. At 4% consistency, the energy for pulling was much higher than for peeling, while at higher consistencies, the peeling effect became more significant. The ink detachment was highly dependant on how the pulp interacted with the printed surface. This interaction was influenced by pulp consistency and the energy applied to the rotor of the Couette device. Copyright © 2008 John Wiley & Sons, Ltd.
Electron transport simulations of a multilead system using the impulse‐response method
Authors: Suzuki Taku , Goto Hidekazu , Hirose Kikuji
Published: May 2008

We introduce a computational procedure for designing nanoscale electronic devices using an impulse‐response method, which is an originally developed simulation method within the framework of real‐space finite‐difference formalism. The impulse‐response method is a new computational scheme for computing the scattering wave function for an incident electron with arbitrary energy in which the impulse wave function is adopted as an initial state of the time evolution. In applying the impulse‐response method to electron transport simulations of two‐dimensional multilead systems, we discuss and illustrate the feasibility of designing a nanoscale multilead electron transportation system. Copyright © 2008 John Wiley & Sons, Ltd.
Antidepressant treatments regulate matrix metalloproteinases‐2 and ‐9 (MMP‐2/MMP‐9) and tissue inhibitors of the metalloproteinases (TIMPS 1–4) in the adult rat hippocampus
Authors: Benekareddy Madhurima , Mehrotra Purvi , Kulkarni Vaishali A. , Ramakrishnan Parvathy , Dias Brian G. , Vaidya Vidita A.
Published: May 2008

Antidepressants induce structural remodeling in the adult hippocampus, including changes in dendritic arbors, axonal sprouting, neurogenesis, and endothelial cell proliferation. Such forms of structural plasticity take place in the context of the extracellular matrix environment and are known to be regulated by matrix metalloproteinases (MMPs), in particular MMP‐2/9, and their endogenous regulators, the tissue inhibitors of the metalloproteinases (TIMPs 1–4). Given the hippocampal structural remodeling associated with antidepressant treatments, we hypothesized that antidepressants may regulate the expression and activity of MMP‐2/9 and TIMPs 1–4. The influence of distinct classes of antidepressants, namely, electroconvulsive seizure, fluoxetine, tranylcypromine, and desipramine, on the gene expression of MMP‐2, MMP‐9, and TIMPs 1–4 in the hippocampus was determined using radioactive in situ hybridization. In addition, zymography studies addressed the regulation of the gelatinase activity of MMP‐2/9 following acute and chronic antidepressant administration. We observed that acute and chronic ECS differentially regulate the transcript levels of MMP‐2/9 and TIMPs 1–4 and also increase gelatinase activity in the hippocampus. Acute and chronic pharmacological antidepressants on the other hand differentially alter the expression of the TIMPs without any observed effect on hippocampal MMP‐2/9 expression or activity. These findings raise the possibility that extracellular matrix modifying enzymes and their endogenous regulators may serve as targets for antidepressant treatments and suggests the possibility that they may contribute to antidepressant‐mediated structural plasticity in the hippocampus. Synapse 62:590–600, 2008. © 2008 Wiley‐Liss, Inc.
Differential synaptic changes in the striatum of subjects with undifferentiated versus paranoid schizophrenia
Authors: Roberts Rosalinda C. , Roche Joy K. , Conley Robert R.
Published: May 2008

Subjects with schizophrenia (SZ) have an increased density of synapses characteristic of corticostriatal or thalamostriatal glutamatergic inputs in the caudate matrix and putamen patches. SZ is a heterogeneous disease in many aspects including symptoms. The purpose of the present study was to determine if the synaptic organization in two different DSM‐i.v. subgroups of SZ was differentially affected. Postmortem striatal tissue was obtained from the Maryland Brain Collection from normal controls (NC), chronic paranoid SZs (SZP), and chronic undifferentiated SZs (SZU). Tissue was prepared for calbindin immunocytochemistry to identify patch matrix compartments, prepared for electron microscopy and analyzed using stereological methods. The synaptic density of asymmetric synapses, characteristic of glutamatergic inputs, was elevated equivalently in striatal patches in the SZP and SZU versus NC. The SZU also had an increased density of asymmetric synapses in the striatal matrix compared to NC. Moreover, symmetric axospinous synapses, characteristic of intrinsic inhibitory inputs and dopaminergic afferents, showed a dichotomy in synaptic density between the SZU and SZP in the striatal and caudate matrix. These data show discreet differences in synaptic organization between SZU and SZP and/or NCs. The results suggest that abnormal corticostriatal and/or corticothalamic inputs to striatal patches may be related to limbic dysfunction, which is perturbed in both subtypes of SZ. The selective increase in axospinous synapses in the matrix of the SZU subgroup compared to the SZP may be related to more severe cognitive problems in that subset of SZ compared to SZP. Synapse 62:616–627, 2008. © 2008 Wiley‐Liss, Inc.
Optimal placement and routing strategies for resilient two‐tiered sensor networks
Authors: Bari Ataul , Jaekel Arunita , Bandyopadhyay Subir
Published: May 2008

In hierarchical sensor networks using relay nodes, sensor nodes are arranged in clusters and higher poweredrelay nodescan be used as cluster heads. The lifetime of such a network is determined primarily by the lifetime of the relay nodes. In this paper, we propose two new integer linear programs (ILPs) formulations for optimal data gathering, which maximize the lifetime of the upper tier relay node network. Unlike most previous approaches considered in the literature, our formulations can generate optimal solutions under thenon‐flow‐splitting model. Experimental results demonstrate that our approach can significantly extend network lifetime, compared to traditional routing schemes, for the non‐flow‐splitting model. The lifetime can be further enhanced by periodic updates of the routing strategy based on the residual energy at each relay node. The proposed rescheduling scheme can be used to handle single or multiple relay node failures. We have also presented a very simple and straightforward algorithm for the placement of relay nodes. The placement algorithm guarantees that all the sensor nodes can communicate with at least one relay node and that the relay node network is at least 2‐connected. This means that failure of a single relay node will not disconnect the network, and data may be routed around the failed node. The worst case performance of the placement algorithm is bounded by a constant with respect to any optimum placement algorithm. Copyright © 2008 John Wiley & Sons, Ltd.
Recent allopolyploid origin of Zygosaccharomyces rouxii strain ATCC 42981
Authors: Gordon Jonathan L. , Wolfe Kenneth H.
Published: May 2008

Zygosaccharomyces rouxii strain ATCC 42981 has been reported to have two copies of several genes including HOG1 and SOD2, whereas the type strain of Z. rouxii (CBS 732) has only one. To investigate the structure of the ATCC 42981 genome we sequenced random fragments from this genome and compared the data to the type strain. We found that ATCC 42981 contains two versions of the ribosomal RNA array, one of which is identical in the ITS1–ITS2 and 26S D1/D2 regions to Z. rouxii CBS 732, while the other is almost identical to a species provisionally named Z. pseudorouxii. We found that most genomic regions from Z. rouxii CBS 732 map in a one‐to‐two fashion to pairs of regions in ATCC 42981, with one of the ATCC 42981 regions having 97–100% DNA sequence identity to CBS 732 and the other having about 80–90% identity. Complete sequencing of regions containing 30 pairs of genes from ATCC 42981 and their orthologues in CBS 732 showed no evidence of the gene deletions or pseudogene formation that might be expected if ATCC 42981 had undergone whole‐genome duplication several million years ago and was in the early stages of gene loss. Instead, we conclude that ATCC 42981 is a Z. rouxii–Z. pseudorouxii interspecies hybrid that was formed so recently that its genome has not had time to decay. Copyright © 2008 John Wiley & Sons, Ltd.
A Standardized Perioperative Surgical Site Infection Care Process Among Children with Stoma Closure: A Before–After Study
Authors: Porras‐Hernandez Juan , Bracho‐Blanchet Eduardo , Tovilla‐Mercado Jose , Vilar‐Compte Diana , Nieto‐Zermeño Jaime , Davila‐Perez Roberto , Teyssier‐Morales Gustavo , Lule‐Dominguez Martha
Published: May 2008

Background

We report on the effectiveness of a standardized perioperative care process for lowering surgical site infection (SSI) rates among children with stoma closure at a tertiary‐care public pediatric teaching hospital in Mexico City.

Methods

All consecutive children with stoma closure operated on between November 2003 and October 2005 were prospectively followed for 30 days postoperatively. We conducted a before–after study to evaluate standardized perioperative bowel‐ and abdominal‐wall care process results on SSI rates.

Results

Seventy‐one patients were operated on, and all completed follow‐up. SSI rates declined from 42.8% (12/28) before to 13.9% (6/43) after the standardization procedure (relative risk (RR) = 3.1; 95% confidence interval (CI) = 1.3–7.2; p = 0.006). SSI independently associated risk factors comprised peristomal skin inflammation >3 mm (odds ratio (OR) = 9.6; 95% CI = 1.8–49.6; p = 0.007) and intraoperative complications (OR = 13.3; 95% CI = 1.4–127.2; p = 0.02). Being operated on during the after‐study period was shown to be a protective factor against SSI (OR = 0.2; 95% CI = 0.4–0.97; p = 0.04).

Conclusion

Standardization was able to reduce SSI rates threefold in children with stoma closure in a short period of time.
Clinical outcomes in pediatric hemodialysis patients in the USA: lessons from CMS’ ESRD CPM Project
Authors: Neu Alicia M. , Frankenfield Diane L.
Published: May 2008

Although prospective randomized trials have provided important information and allowed the development of evidence-based guidelines in adult hemodialysis (HD) patients, with approximately 800 prevalent pediatric HD patients in the United States, such studies are difficult to perform in this population. Observational data obtained through the Center for Medicare & Medicaid Services’ (CMS’) End Stage Renal Disease (ESRD) Clinical Performance Measures (CPM) Project have allowed description of the clinical care provided to pediatric HD patients as well as identification of risk factors for failure to reach adult targets for clinical parameters such as hemoglobin, single-pool Kt/V (spKt/V) and serum albumin. In addition, studies linking data from the ESRD CPM Project and the United States Renal Data System have allowed evaluation of associations between achievement of those targets and the outcomes of hospitalization and death. The results of those studies, while unable to prove cause and effect, suggest that the adult ESRD CPM targets may assist in identifying pediatric HD patients at risk for poor outcomes.
Skills training in minimally invasive surgery in Dutch obstetrics and gynecology residency curriculum
Authors: Hiemstra Ellen , Kolkman Wendela , Jansen Frank Willem
Published: May 2008

The complexity of acquiring minimally invasive surgical (MIS) skills, combined with smaller case volumes for residents have pushed the development of skills training facilities on simulators outside the operating room (OR). Medico-legal and financial constraints have stimulated this development even more. However, the implementation of simulator training into a residency curriculum is shown to be troublesome. MIS skills training is organized in a uniform and easily applicable way in the Dutch obstetrics and gynecology residency curriculum. Every resident is obliged to attend the same basic surgical skills course, named Cobra-alpha course, intentionally during postgraduate year (PGY) 1 or 2. Furthermore, surgical skills are trained, evaluated and expanded on simulators in teaching hospitals. Additional to the Cobra-alpha course, residents may attend advanced training courses and congresses focusing on laparoscopy and hysteroscopy. This organization guarantees a uniform introduction to MIS skills training for every resident. However, preconditions for continuous training and evaluation after this introduction have to be optimized.