bluuebunny/crossref_metadata_2025 huggingface dataset:
Do miRNAs have a deep evolutionary history?
Authors: Tarver James E. , Donoghue Philip C. J. , Peterson Kevin J.
Published: July 2012

The recent discovery of microRNAs (miRNAs) in unicellular eukaryotes, including miRNAs known previously only from animals or plants, implies that miRNAs have a deep evolutionary history among eukaryotes. This contrasts with the prevailing view that miRNAs evolved convergently in animals and plants. We re‐evaluate the evidence and find that none of the 73 plant and animal miRNAs described from protists meet the required criteria for miRNA annotation and, by implication, animals and plants did not acquire any of their respective miRNA genes from the crown ancestor of eukaryotes. Furthermore, of the 159 novel miRNAs previously identified among the seven species of unicellular protists examined, only 28 from the algae Ectocarpus and Chlamydomonas, meet the criteria for miRNA annotation. Therefore, at present only five groups of eukaryotes are known to possess miRNAs, indicating that miRNAs have evolved independently within eukaryotes through exaptation of their shared inherited RNAi machinery.
Flash Crystallization – Mechanism in the Crystallizer and Operating Behavior of the Continuous Process
Authors: Gebauer Jörn , Kaiser Raffael , Kind M.
Published: July 2012

Beim Flash‐Kristallisationsprozess werden im Kristallisationsapparat gezielt feine Kristalle (L50,3 = 20 – 70 μm) hergestellt, damit aus diesen nach der Fest/Flüssig‐Trennung in einem formgebenden Prozessschritt (Agglomeration) Partikel in gewünschter Form und Größe hergestellt werden können. Die hier vorgestellten Untersuchungen behandeln die Wirkungsmechanismen im Kristallisator, das Betriebsverhalten des kontinuierlichen Prozesses sowie die Morphologie des erzeugten Kristallisats. Es konnten Erkenntnisse für ein weitergehendes Prozessverständnis erlangt werden. Diese sind notwendig, um den Flash‐Kristallisationsprozess aus dem Labor‐ und Pilotmaßstab in einen produktionstechnischen Maßstab übertragen zu können.
Prostate‐specific antigen screening for prostate cancer and the risk of overt metastatic disease at presentation
Authors: Scosyrev Emil , Wu Guan , Mohile Supriya , Messing Edward M.
Published: July 2012

BACKGROUND:

The objective of this study was to estimate the total number of patients who would be expected to present with metastatic (M1) prostate cancer (PC) in the modern US population in a given year if the age‐specific and race‐specific annual incidence rates of M1 PC were the same as the rates in the era before prostate‐specific antigen (PSA) testing.

METHODS:

The authors computed the total number of men who presented with M1 PC in the Surveillance, Epidemiology, and End Results (SEER) 9 registries area in the year 2008 (the most recent SEER year) and estimated the number of cases that would be expected to occur in this area in the year 2008 in the absence of PSA testing. The expected number was computed by multiplying each age‐race–specific average annual incidence rate from the pre‐PSA era (1983‐1985) by the number of men in the corresponding age‐race category in the year 2008 and adding the products.

RESULTS:

In the year 2008, the observed and expected numbers of men presenting with M1 PC in the SEER 9 registries area were 739 and 2277, respectively, with an expected‐to‐observed ratio of 3.1 (95% confidence interval, 3.0‐3.2). If this ratio was applied to the total US population in the year 2008, then the total number of men presenting with M1 PC in that year would be equal to approximately 25,000 instead of the approximately 8000 actually observed.

CONCLUSIONS:

If the pre‐PSA era rates were present in the modern US population, then the total number of men presenting with M1 PC would be approximately 3 times greater than the number actually observed. Cancer 2012. © 2012 American Cancer Society.
A Family of Discrete Magnetically Switchable Nanoballs
Authors: Duriska Martin B. , Neville Suzanne M. , Moubaraki Boujemaa , Murray Keith S. , Balde Chérif , Létard Jean‐François , Kepert Cameron J. , Batten Stuart R.
Published: July 2012

The thermal and light‐induced magnetic properties of a family of discrete magnetically switchable “nanoball” species (3 nm in diameter) is reported. The self‐assembly of these materials is accomplished by the use of the metallo building block, [Cu([Tp4‐py])(NCCH3)] ([Tp4‐py]=tris‐[3‐(4'‐pyridyl)pyrazol‐1‐yl]hydroborate), combined with a [Fe(NCX)2] (X=S, Se and BH3) species. We previously showed that the thiocyanate analogue (Fe(NCS)‐nano) undergoes a thermal and light‐induced spin crossover (SCO)—the largest such discrete SCO material reported. Now included in this family are the Se and BH3 analogues, Fe(NCSe)‐nano and Fe(NCBH3)‐nano, which show increased thermal transition temperatures (T1/2=124 K, 162 and 173 K). This variation in transition temperature over the series S<Se<BH3 results in diverse photomagnetic properties, such that the light‐induced excited spin state trapping (LIESST) effect is exhibited to varying degrees and at different temperatures by the S, Se and BH3 analogues.
Complex boron redistribution kinetics in strongly doped polycrystalline‐silicon/nitrogen‐doped‐silicon thin bi‐layers
Authors: Abadli S. , Mansour F. , Pereira E. Bedel
Published: July 2012

We have investigated the complex behaviour of boron (B) redistribution process via silicon thin bi‐layers interface. It concerns the instantaneous kinetics of B transfer, trapping, clustering and segregation during the thermal B activation annealing. The used silicon bi‐layers have been obtained by low pressure chemical vapor deposition (LPCVD) method at 480 °C, by using in‐situ nitrogen‐doped‐silicon (NiDoS) layer and strongly B doped polycrystalline‐silicon (P+) layer. To avoid long‐range B redistributions, thermal annealing was carried out at relatively low‐temperatures (600 °C and 700 °C) for various times ranging between 30 min and 2 h. To investigate the experimental secondary ion mass spectroscopy (SIMS) doping profiles, a redistribution model well adapted to the particular structure of two thin layers and to the effects of strong‐concentrations has been established. The good adjustment of the simulated profiles with the experimental SIMS profiles allowed a fundamental understanding about the instantaneous physical phenomena giving and disturbing the complex B redistribution profiles‐shoulders. The increasing kinetics of the B peak concentration near the bi‐layers interface is well reproduced by the established model.
Crystalline Iron Oxohalide Nanotube Pea Pods
Authors: Zimmermann Iwan , Johnsson Mats , Lidin Sven
Published: July 2012

Compounds Fe7Sb3(PO4)3O6Cl3 and Fe7Sb3(PO4)3O6Br3 are the first iron phosphates containing SbIII. They were synthesized by chemical vapor transport reactions, and their crystal structures were characterized by single‐crystal X‐ray diffraction. The compounds are isostructural and crystallize in the orthorhombic space group Pnma. Tubular Fe7(PO4)3O6X3 units (X = Cl, Br) are linked by SbO4 groups to build up a framework. The tubular units consist of an outer part made up of [FeO5X] octahedra where the Fe atoms are arranged to resemble a nanotube. Inside the tubes there are phosphate groups, and at the very center there is a chain of face‐sharing [FeO6] octahedra.
DNA methylation alterations in response to pesticide exposure in vitro
Authors: Zhang Xiao , Wallace Andrew D. , Du Pan , Kibbe Warren A. , Jafari Nadereh , Xie Hehuang , Lin Simon , Baccarelli Andrea , Soares Marcelo Bento , Hou Lifang
Published: July 2012

Although pesticides are subject to extensive carcinogenicity testing before regulatory approval, pesticide exposure has repeatedly been associated with various cancers. This suggests that pesticides may cause cancer via nonmutagenicity mechanisms. The present study provides evidence to support the hypothesis that pesticide‐induced cancer may be mediated in part by epigenetic mechanisms. We examined whether exposure to seven commonly used pesticides (i.e., fonofos, parathion, terbufos, chlorpyrifos, diazinon, malathion, and phorate) induces DNA methylation alterations in vitro. We conducted genome‐wide DNA methylation analyses on DNA samples obtained from the human hematopoietic K562 cell line exposed to ethanol (control) and several organophosphate pesticides (OPs) using the Illumina Infinium HumanMethylation27 BeadChip. Bayesian‐adjusted t‐tests were used to identify differentially methylated gene promoter CpG sites. In this report, we present our results on three pesticides (fonofos, parathion, and terbufos) that clustered together based on principle component analysis and hierarchical clustering. These three pesticides induced similar methylation changes in the promoter regions of 712 genes, while also exhibiting their own OP‐specific methylation alterations. Functional analysis of methylation changes specific to each OP, or common to all three OPs, revealed that differential methylation was associated with numerous genes that are involved in carcinogenesis‐related processes. Our results provide experimental evidence that pesticides may modify gene promoter DNA methylation levels, suggesting that epigenetic mechanisms may contribute to pesticide‐induced carcinogenesis. Further studies in other cell types and human samples are required, as well as determining the impact of these methylation changes on gene expression. Environ. Mol. Mutagen. 2012. © 2012 Wiley Periodicals, Inc.
Association of endocrine-disrupting chemicals with total organic carbon in riverine water and suspended particulate matter from the Pearl River, China
Authors: Gong Jian , Ran Yong , Chen Diyun , Yang Yu , Zeng Eddy Y.
Published: July 2012

The distribution of endocrine-disrupting chemicals (EDCs) and its relationship with dissolved and particulate organic carbon (DOC and POC) was investigated in selected rivers of the Pearl River Delta, South China. The aqueous concentrations (average; ng/L) and particulate concentrations (average; ng/g, dry wt) for 4-tert-octylphenol (OP), 4-nonylphenol (NP), bisphenol A (BPA), and estrone (E1) were in the ranges of not detectable to 153 (31.8), 276 to 2,457 (1,178), 8.4 to 628 (161), and less than 1.5 to 11.5 (3.2), respectively, and 4.4 to 402 (98.1), 342 to 12,053 (4,922), 12.3 to 758 (128), and not detectable to 14.4, respectively. The highly significant correlation of EDCs with DOC and POC, and the similar regression slopes, implied the critical importance of DOC and POC on the distribution, transport, and fate of EDCs in the aquatic environment. The in situ particle–water partition coefficients (log KOC) for OP (4.89 ± 0.41), NP (5.05 ± 0.33), and BPA (4.34 ± 0.50) were close to those reported by other field studies, but one to two orders of magnitude higher than those predicted with n-octanol–water partition coefficient (KOW). The higher KOC values were attributed to the combined effects of low EDC concentrations, nonlinear sorption, and heterogeneity of POC and DOC. Moreover, a regression between in-situ KOC and KOW for phenolic xenoestrogens was observed (log KOC = 0.625 × log KOW + 2.28, r2 = 0.99), suggesting that hydrophobicity contributed predominantly to the overall sorption of OP, NP, and BPA. Environ. Toxicol. Chem. 2012; 31: 2456–2464. © 2012 SETAC
How do stream organisms respond to, and influence, the concentration of titanium dioxide nanoparticles? A mesocosm study with algae and herbivores
Authors: Kulacki Konrad J. , Cardinale Bradley J. , Keller Arturo A. , Bier Raven , Dickson Helen
Published: July 2012

The biologically active properties of many nanomaterials, coupled with their rapidly expanding production and use, has generated concern that certain types of nanoparticles could have unintended impacts when released into natural ecosystems. In the present study, the authors report the results of an experiment in which they grew three common species of stream algae as monocultures and together as polycultures in the biofilms of stream mesocosms that were exposed to 0, 0.1, or 1.0 ppm nanoparticle titanium dioxide (nTiO2). The nTiO2 did not alter the growth trajectory of any algal biofilm over 10+ generations. However, Ti accrual in biofilms not only differed among the algal species but was also higher in polycultures than in the average monoculture. Variation in accrual among species compositions was readily predicted by differences in the total biomass achieved by the different biofilms. When biofilms were fed to the herbivorous snail Physa acuta at the end of the experiment, initial concentrations of nTiO2 did not alter short-term rates of herbivory. However, because of differences in palatability among the algae, biofilm composition influenced the amount of nTiO2 that accumulated in the herbivore tissue. The results have important implications for understanding how efficiently nTiO2 is removed from surface waters and the potential transfer of nanomaterials to higher trophic levels. Environ. Toxicol. Chem. 2012; 31: 2414–2422. © 2012 SETAC
Does Index Futures Trading Reduce Volatility in the Chinese Stock Market? A Panel Data Evaluation Approach
Authors: Chen Haiqiang , Han Qian , Li Yingxing , Wu Kai
Published: July 2012

This study investigates the effect of introducing index futures trading on the spot price volatility in the Chinese stock market. We employ a recently developed panel data policy evaluation approach (Hsiao, Ching, and Wan, 2011) to construct counterfactuals of the spot market volatility, based mainly on cross‐sectional correlations between the Chinese and international stock markets. This new method does not need to specify a particular regression or a time‐series model for the volatility process around the introduction date of index futures trading, and thus avoids the potential omitted variable bias caused by uncontrolled market factors in the existing literature. Our results provide empirical evidence that the introduction of index futures trading significantly reduces the volatility of the Chinese stock market, which is robust to different model selection criteria and various prediction approaches. © 2012 Wiley Periodicals, Inc. Jrl Fut Mark 33:1167–1190, 2013
Analysis of regional recurrence after negative sentinel lymph node biopsy for head and neck melanoma
Authors: McDonald Kelly , Page Andrew J. , Jordan Sumanas W. , Chu Carrie , Hestley Andrea , Delman Keith A. , Murray Douglas R. , Carlson Grant W.
Published: July 2012

Background

The head and neck have a rich lymphatic drainage and complex anatomy, which complicate sentinel lymph node (SLN) biopsy for melanoma. The incidence of regional recurrence after a negative SLN biopsy has been shown to be higher than that at other sites. Compounding factors in this scenario were analyzed to determine their impact on both SLN status and survival.

Methods

A retrospective review of a prospective database of 315 patients who underwent SLN biopsy for head and neck melanoma from 1994 to 2009 was performed. A false‐negative SLN biopsy was defined as a regional recurrence in a previously mapped nodal basin.

Results

In all, 267 patients (84.8%) were SLN negative (SLN−) and 48 patients (15.2%) were SLN positive (SLN+). The false‐negative SLN biopsy occurred in 17 patients (6.4%). The mean follow‐up was 37.6 months (3–152 months). The false‐negative SLN and SLN+ patients were similar with respect to patient age and sex and primary melanoma tumor thickness and ulceration. The site of the primary melanoma and the lymphatic drainage patterns did not influence the false‐negative biopsy rate. The mean survival was SLN− 119.3 months (95% confidence interval [CI], 106.1–132.5, p < .001), SLN+ 73.4 months (95% CI, 52.3–94.4), and the false‐negative SLN 70.7 months (95% CI, 54.2–87.1).

Conclusions

The risk of a false‐negative SLN biopsy in head and neck melanoma is independent of primary site and lymphatic drainage pattern. Patients with head and neck melanoma who have a regional recurrence after a negative SLN biopsy do not have a worse survival than that of patients who are initially SLN positive. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
“Mystic” transient recurrent nerve palsy after thyroid surgery
Authors: Altorjay Áron , Rüll Miklós , Paál Balázs , Csáti Géza , Szilágyi Anna
Published: July 2012

Background

The mechanism of transient recurrent laryngeal nerve (RLN) palsy remains unclear.

Methods

Samples were harvested from the RLN adjacent thyroid capsule and perineural fascia during 223 lobectomies and 89 RLNs from cadavers were used for histologic and immunohistologic evaluation. Intraoperative chromoendoscopic features of the RLN were compared with postoperative ear, nose, and throat examinations.

Results

Those nerves that macroscopically seem to be single‐branched (35 of 89 = 39.3%), microscopically consist of multiple fascicles in most of the cases (23 of 35 = 65.7%), resembling a plexus more than a single cord. Chronic lymphocytic infiltration of the thyroid capsule adjacent to the RLN was present in 29% (65 of 223) of the cases. The perineural fascia showed lymphocytic (18 of 223 = 8.1%) or granulocytic (7 of 223 = 3.1%) infiltration.

Conclusions

The origin of transient RLN palsy is multifactorial: plexus shaped microscopic nerve structure with or without branches, frame‐like adventitial tissue, variable epineurium, inflammatory changes that involve not only the thyroid capsule but the perineural fascia, resultant nerve edema, and diffuse microhemorrhages by injury of fragile capillaries. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
A new angle to mandibular reconstruction: The scapular tip free flap
Authors: Yoo John , Dowthwaite Samuel A. , Fung Kevin , Franklin Jason , Nichols Anthony
Published: July 2012

Background

The purpose of this study was to review our experience with the scapular tip free flap for mandibular reconstruction, describe the surgical approach, and highlight specific clinical applications.

Methods

A retrospective review of all patients undergoing oromandibular reconstruction using a scapular tip free flap at the London Health Sciences Centre was undertaken. Patient demographics, surgical data, and early outcomes were collated.

Results

Twenty patients were identified. The majority involved mandibular angle and short segment defects (16 of 20). Average length of the segmental defect was 6.2 cm with the longest measuring 8 cm. A single patient required an osteotomy. Six were revision cases. No vein grafts were required. One complete flap failure occurred.

Conclusions

The natural scapular angle makes the scapular tip flap ideal for mandibular angle reconstruction. Short bone segments can be harvested with little donor‐site morbidity. The long pedicle length may obviate vein grafts. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
Update and external validation of a head and neck cancer prognostic model
Authors: Datema Frank R. , Ferrier Marciano B. , Vergouwe Yvonne , Moya Ana , Molenaar Jan , Piccirillo Jay F. , Baatenburg de Jong Robert J.
Published: July 2012

Background

The purpose of this study was to update and external validation of a prognostic model that is able to predict the survival probability of newly diagnosed patients with head and neck cancer.

Methods

Our original prognostic model is based on historical data of 1371 patients with primary head and neck cancer, diagnosed and treated in the Leiden University Medical Center, between 1981 and 1999. The model contains the predictors age, sex, tumor site, TNM‐classification, prior tumors, and comorbidity. We updated the model with follow‐up data until January 2010. The updated model was then externally validated in 598 patients with head and neck cancer from the Siteman Cancer Center/Barnes‐Jewish Hospital, St. Louis, Missouri.

Results

Median follow‐up was 5.5 years (range, 0–25.5). Only 2.5% of patients were lost to follow‐up. During follow‐up 1099 patients (80.2%) passed away. Discrimination of the updated prognostic model was good, with a C‐index of 0.73 after internal validation. The discrimination was slightly lower in the external validation set (C‐index, 0.69). The predicted 2‐year and 5‐year survival rates correlated satisfactorily with some slight deviations from the perfect calibration line.

Conclusions

We used recent follow‐up information to update the Leiden prognostic model for newly diagnosed patients with head and neck cancer. The model showed acceptably good calibration and discrimination results in internal and external validation procedures. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
Pilot, randomized trial of resistance exercise during radiation therapy for head and neck cancer
Authors: Rogers Laura Q. , Anton Philip M. , Fogleman Amanda , Hopkins–Price Patricia , Verhulst Steven , Rao Krishna , Malone James , Robbs Randy , Courneya Kerry S. , Nanavati Parashar , Mansfield Sara , Robbins K. Thomas
Published: July 2012

Background

The purpose of this study was to determine the feasibility of a randomized trial of resistance exercise in patients with head and neck cancer receiving radiation.

Methods

Fifteen patients with head and neck cancer receiving radiation were randomized to resistance exercise (using resistance bands) or control group. Resistance exercise occurred at the radiation therapy site (weeks 1–6) and home (weeks 7–12).

Results

No serious adverse events occurred related to resistance exercise. Medium to large effect size differences favoring resistance exercise versus control group were noted for perceived fatigue at 6 weeks (smaller increase in fatigue for resistance exercise group; 7.4 vs 15.4, effect size [d] = −0.64), quality of life at 6 weeks (−7.0 vs −14.4, d = 0.52), and chair rise time (seconds) at 6 and 12 weeks (−1.6 vs 0.4, d = −.63 and −1.9 vs 0.1, d = −0.60, respectively).

Conclusions

Resistance exercise is safe and feasible in patients with head and neck cancer receiving radiation; a definitive trial is warranted. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
Demographic diversity, communication and learning behaviour in healthcare groups
Authors: Curşeu Petru Lucian
Published: July 2012

An integrative model of group learning was tested in a sample of 40 healthcare groups (434 respondents), and the results show that age diversity reduces the frequency of face‐to‐face communication whereas educational diversity reduces the frequency of virtual communication in healthcare groups. Frequency of communication (both face‐to‐face and virtual), in turn, positively impacts on the emergence of trust and psychological safety, which are essential drivers of learning behaviours in healthcare groups. Additional results show that average educational achievement within groups is conducive for communication frequency (both face‐to‐face and virtual), whereas mean age within groups has a negative association with the use of virtual communication in healthcare groups. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of viscosity variation on natural convection flow of water–alumina nanofluid in an annulus with internal heat generation
Authors: Nasrin Rehena , Alim M.A. , Chamkha Ali J.
Published: July 2012

Heat transfer enhancement in a horizontal annulus using the variable viscosity property of an Al2O3–water nanofluid is investigated. Two different viscosity models are used to evaluate heat transfer enhancement in the annulus. The base case uses the Pak and Cho model and the Brinkman model for viscosity which take into account the dependence of this property on temperature and nanoparticle volume fraction. The inner surface of the annulus is heated uniformly by a constant heat flux qw and the outer boundary is kept at a constant temperature Tc. The nanofluid generates heat internally. The governing equations are solved numerically subject to appropriate boundary conditions by a penalty finite‐element method. It is observed that for a fixed Prandtl number Pr = 6.2, Rayleigh number Ra = 104 and solid volume fraction ϕ = 10%, the average Nusselt number is enhanced by diminishing the heat generation parameter, mean diameter of nanoparticles, and diameter of the inner circle. The mean temperature for the fluids (nanofluid and base fluid) corresponding to the above mentioned parameters is plotted as well. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21016
Forced convection and entropy generation inside a channel with a heat‐generating porous block
Authors: Delavar Mojtaba Aghajani , Hedayatpour Mehdi
Published: July 2012

The flow pattern and heat transfer in a composite system containing a porous region has received considerable attention due to its importance in many engineering applications. In this study a thermal lattice Boltzmann model with nine velocities, D2Q9, is employed to investigate the fluid flow, heat transfer, and entropy generation inside a channel with a heat‐generating porous block. The effects of the porous block's length, porosity, and the Reynolds number, overflow pattern, heat transfer, and entropy generation were studied. The mentioned parameters have different effects on heat transfer and conjugate phenomena. By increasing the block length, Reynolds number, and porosity the dimensionless entropy generation will reduce. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21017
Finding the most appropriate precipitation probability distribution for stochastic weather generation and hydrological modelling in Nordic watersheds
Authors: Li Zhi , Brissette Francois , Chen Jie
Published: July 2012

Six precipitation probability distributions (exponential, Gamma, Weibull, skewed normal, mixed exponential and hybrid exponential/Pareto distributions) are evaluated on their ability to reproduce the statistics of the original observed time series. Each probability distribution is also indirectly assessed by looking at its ability to reproduce key hydrological variables after being used as inputs to a lumped hydrological model. Data from 24 weather stations and two watersheds (Chute‐du‐Diable and Yamaska watersheds) in the province of Quebec (Canada) were used for this assessment. Various indices or statistics, such as the mean, variance, frequency distribution and extreme values are used to quantify the performance in simulating the precipitation and discharge. Performance in reproducing key statistics of the precipitation time series is well correlated to the number of parameters of the distribution function, and the three‐parameter precipitation models outperform the other models, with the mixed exponential distribution being the best at simulating daily precipitation. The advantage of using more complex precipitation distributions is not as clear‐cut when the simulated time series are used to drive a hydrological model. Although the advantage of using functions with more parameters is not nearly as obvious, the mixed exponential distribution appears nonetheless as the best candidate for hydrological modelling. The implications of choosing a distribution function with respect to hydrological modelling and climate change impact studies are also discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Water balance of the Salado–Juramento river basin (Argentina)
Authors: Virginia Venturini , Krepper Carlos
Published: July 2012

A lumped water balance model was used to derive a monthly water storage series in the Salado–Juramento southern basin, for the period 1954–1986. The evapotranspiration term was estimated using the Bouchet's complementary relationship. Different evapotranspiration formulas following the concepts of potential evapotranspiration and wet environmental evapotranspiration were used. The regional average groundwater levels and the specific yield were used to tune Bouchet's equation. The extrapolation of the water storage series to a secular period (1901–2002) was achieved using a synthetic annual discharge series. The water storage was deficient for most of the century, i.e. more than 60 years; nevertheless in the last 30 years, the system recovers half of the water previously lost. The singular spectral analysis showed that a significant low‐frequency signal is present in the water storage and precipitation series. The main cause of water storage variability would be given by precipitation, in spite of the vast anthropogenic changes on the basin. Anthropogenic effects would be reflected in the river discharges, where no significant signal is detected before 1970; however, an annual signal is insinuated after that year. The conclusions of this work could be different if we only looked at the 1954–1986 period. The results of that period suggest that the basin is primarily accumulating water instead of being mainly in deficit. Thus, here we demonstrated the importance of the secular analysis to illustrate the complete basin behaviour. Copyright © 2012 John Wiley & Sons, Ltd.
Surface water–groundwater interaction at restored streams and associated reference reaches
Authors: Daniluk Timothy L. , Lautz Laura K. , Gordon Ryan P. , Endreny Theodore A.
Published: July 2012

Stream restoration goals include improving habitat and water quality through reconstruction of morphological features found at analogous, pristine stream reaches. Enhancing hyporheic exchange may facilitate achieving these goals. Although hyporheic exchange at restoration sites has been explored in a few previous studies, comparative studies of restored versus reference or control streams are largely absent. We hypothesized that restoration cross‐vanes enhance hyporheic exchange, resulting in biogeochemical alteration of stream water chemistry in the streambed. Two streams restored using cross‐vanes to control erosion and improve habitat were compared with their associated reference reaches, which provided the basis for the restoration design. Thirteen temperature profile rods with vertically stacked sensors were installed at each site for 2 weeks. Heat tracing was used to quantify vertical flux in the streambed from the diurnal temperature fluctuations in the subsurface. Stream water and bed pore waters from mini‐piezometers were analysed for ion and nutrient chemistry. In general, mean vertical flux rates through the streambed were small throughout reference sites (−0.3 to 0.3 m/day) and at most locations at restored sites. Immediately adjacent to cross‐vanes, vertical flux rates were larger (up to 3.5 m/day). Geochemistry of pore waters shows distinct differences in the sources for the reference and restored sites. Strong downwelling zones adjacent to cross‐vanes showed high dissolved oxygen (10.75 mg/l) and geochemistry in the streambed similar to surface water. Reference sites had lower dissolved oxygen in the streambed (0.66–5.14 mg/l), and geochemical patterns suggest a mixture of discharging groundwater and surface water in the hyporheic zone. Restored sites also clearly show sulfate and nitrate reduction occurring in the streambed, which is not observed at the reference sites. The stream restoration sites studied here enhance rapid hyporheic exchange, but upwelling of groundwater has a stronger influence on streambed geochemistry at reference sites. Copyright © 2012 John Wiley & Sons, Ltd.
Assessment of modified gold surfaced titanium implants on skeletal fixation
Authors: Zainali Kasra , Danscher Gorm , Jakobsen Thomas , Baas Jorgen , Møller Per , Bechtold Joan E. , Soballe Kjeld
Published: July 2012

Noncemented implants are the primary choice for younger patients undergoing total hip replacements. However, the major concern in this group of patients regarding revision is the concern from wear particles, periimplant inflammation, and subsequently aseptic implant loosening. Macrophages have been shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti‐inflammatory manner by inhibiting cellular NF‐κB‐DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration and increase mechanical fixation. Cylindrical porous coated Ti‐6Al‐4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out tests and stereological histomorphometrical analyses showed no statistically significant differences in the two groups. The unchanged parameters are considered an improvement of the coating properties, as a previous complete gold‐coated implant showed inferior mechanical fixation and reduced osseointegration compared to control titanium implants in a similar model. Since sufficient early mechanical fixation is achieved with this new coating, it is reasonable to investigate the implant further in long‐term studies. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:195–202, 2013.
Correlating macrophage morphology and cytokine production resulting from biomaterial contact
Authors: Lee Hyun‐Su , Stachelek Stanley J. , Tomczyk Nancy , Finley Matthew J. , Composto Russell J. , Eckmann David M.
Published: July 2012

The morphological and inflammatory responses of adherent macrophages are correlated to evaluate the biocompatibility of surfaces. Monocyte‐derived macrophage (MDM), THP‐1, and THP‐1 cells expressing GFP‐actin chimeric protein were seeded onto glass, polyurethane (PU), and glass surface modified with quaternary ammonium salt functionalized chitosan (CH‐Q) and hyaluronic acid (HA). Using confocal microscopy, the surface area, volume and 3D shape factor of adherent macrophages was quantified. For comparison, functional consequences of cell‐surface interactions that activate macrophages and thereby elicit secretion of a proinflammatory cytokine were evaluated. Using an enzyme linked immune sorbent assay, tumor necrosis factor‐alpha (TNF‐α) was measured. On glass, macrophages exhibited mainly an amoeboid shape, exhibited the largest surface area, volume, and 3D shape factor and produced the most TNF‐α. On PU, macrophages displayed mainly a hemispherical shape, exhibited an intermediate volume, surface area and 3D shape factor, and produced moderate TNF‐α. In contrast, on CH‐Q and HA surfaces, macrophages were spherical, exhibited the smallest volume, surface area, and 3D shape factor, and produced the least TNF‐α. These studies begin to validate the use of GFP‐actin‐modified MDM as a novel tool to correlate cell morphology with inflammatory cell response. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:203–212, 2013.
Modulating patterned adhesion and repulsion of HEK 293 cells on microengineered parylene‐C/SiO2 substrates
Authors: Hughes M. A. , Bunting A. S. , Cameron K. , Murray A. F. , Shipston M. J.
Published: July 2012

This article describes high resolution patterning of HEK 293 cells on a construct of micropatterned parylene‐C and silicon dioxide. Photolithographic patterning of parylene‐C on silicon dioxide is an established and consistent process. Activation of patterns by immersion in serum has previously enabled patterning of murine hippocampal neurons and glia, as well as the human hNT cell line. Adapting this protocol we now illustrate high resolution patterning of the HEK 293 cell line. We explore hypotheses that patterning is mediated by transmembrane integrin interactions with differentially absorbed serum proteins, and also by etching the surface substrate with piranha solution. Using rationalized protein activation solutions in place of serum, we show that cell patterning can be modulated or even inverted. These cell‐patterning findings assist our wider goal of engineering and interfacing functional neuronal networks via a silicon semiconductor platform. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Ring‐opening polymerization of genipin and its long‐range crosslinking effect on collagen hydrogel
Authors: Mu Changdao , Zhang Ke , Lin Wei , Li Defu
Published: July 2012

Polymeric genipin macromers, prepared by ring‐opening polymerization at various pH values, are used as crosslinking agents to fix collagen hydrogels. The results indicate that as the dark color of polymeric genipin itself and the networks formed by long‐range intermolecular crosslinking, the genipin‐fixed collagen hydrogels displace darker color. The polymeric genipin prepared at higher pH value needs longer time to fully crosslink with collagen molecules. Moreover, polymerization of genipin reduces the yield of genipin‐fixed collagen hydrogels due to low extent of crosslinking. Specially, the microscope photographs present the porous networks structures of genipin‐fixed collagen hydrogels. The pore size increases with the increase in polymerization degree of genipin. The data of FTIR indicate the likely transition of –NH2 groups in collagen chains into C=N. Owning to much more number of hydrophilic groups and more porous networks, collagen hydrogels fixed by genipin with higher polymerization degree have higher water absorption capacity. The equilibrium swelling of genipin‐fixed collagen hydrogels is pH‐responsive, which show “M” type changes with the pH values. The results obtained in the study suggest that the polymeric genipin prepared at various pH values lead to significant influence to the crosslinking characteristics and properties of collagen hydrogels. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Tensile testing as a novel method for quantitatively evaluating bioabsorbable material degradation
Authors: Bowen Patrick K. , Gelbaugh Jesse A. , Mercier Phillip J. , Goldman Jeremy , Drelich Jaroslaw
Published: July 2012

Bioabsorbable metallic materials have become a topic of interest in the field of interventional cardiology because of their potential application in stents. A well‐defined, quantitative method for evaluating the degradation rate of candidate materials is currently needed in this area. In this study, biodegradation of 0.25‐mm iron and magnesium wires was simulated in vitro through immersion in cell‐culture medium with and without a fibrin coating (meant to imitate the neointima). The immersed samples were corroded under physiological conditions (37°C, 5% CO2). Iron degraded in a highly localized manner, producing voluminous corrosion product while magnesium degraded more uniformly. To estimate the degradation rate in a quantitative manner, both raw and corroded samples underwent tensile testing using a protocol similar to that used on polymeric nanofibers. The effective ultimate tensile stress (tensile stress holding constant cross‐sectional area) was determined to be the mechanical metric that exhibited the smallest amount of variability. When the effective tensile stress data were aggregated, a statistically significant downward, linear trend in strength was observed in both materials (Fe and Mg) with and without the fibrin coating. It was also demonstrated that tensile testing is able to distinguish between the higher degradation rate of the bare wires and the lower degradation rate of the fibrin‐coated wires with confidence. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Characterization and preosteoblastic behavior of hydroxyapatite‐deposited nanotube surface of titanium prepared by anodization coupled with alternative immersion method
Authors: Gu Ying‐Xin , Du Juan , Zhao Jing‐Mei , Si Mi‐Si , Mo Jia‐Ji , Lai Hong‐Chang
Published: July 2012

The modification on the titanium (Ti) implant surface is an effective method to improve the bioactivity of Ti. In this study, a hydroxyapatite (HA)‐deposited nanotubular Ti surface was prepared by anodization coupled with an alternative immersion method (AIM). Surface physicochemical characteristics including morphology, microstructure, composition, roughness were evaluated by field‐emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), Fourier‐transformed infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Preosteoblast cell (MC3T3‐E1) behavior on the HA‐deposited nanotube surface, including cell morphology, proliferation, alkaline phosphatase (ALP) activity, osteocalcin secretion, and mineralization, were also investigated. The untreated nanotube surface and bare Ti were used as controls. The results showed that synthetic HA crystals could be efficiently grown on/inside the nanotubes after AIM treatment in saturated Ca(OH)2 and 0.02M (NH4)2HPO4. The amount of synthetic HA on nanotube layer was dependent on the number of dipping cycles. Significant increases in ALP activity and osteocalcin production on day 7 and 14 and calcium deposition on day 21 (P < 0.05) were observed for HA‐deposited nanotubular Ti surface when compared with untreated nanotube layer and bare Ti. However, the cell proliferation rate on HA‐deposited nanotube surfaces was slowed down significantly (P < 0.05). All these results indicated that this HA‐deposited nanotube surface might have the potential benefit to enhance implant osseointegration. The synthetic HA TiO2 nanotube loading might be a highly promising path to improve the bioactivity of Ti‐based implants. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
GPU‐accelerated computation of electron transfer
Authors: Höfinger Siegfried , Acocella Angela , Pop Sergiu C. , Narumi Tetsu , Yasuoka Kenji , Beu Titus , Zerbetto Francesco
Published: July 2012

Electron transfer is a fundamental process that can be studied with the help of computer simulation. The underlying quantum mechanical description renders the problem a computationally intensive application. In this study, we probe the graphics processing unit (GPU) for suitability to this type of problem. Time‐critical components are identified via profiling of an existing implementation and several different variants are tested involving the GPU at increasing levels of abstraction. A publicly available library supporting basic linear algebra operations on the GPU turns out to accelerate the computation approximately 50‐fold with minor dependence on actual problem size. The performance gain does not compromise numerical accuracy and is of significant value for practical purposes. © 2012 Wiley Periodicals, Inc.
On Perfect 2‐Colorings of Johnson Graphs J(v, 3)
Authors: Gavrilyuk Alexander L. , Goryainov Sergey V.
Published: July 2012

We study the perfect 2‐colorings (also known as the equitable partitions into two parts or the completely regular codes with covering radius 1) of the Johnson graphs . In particular, we classify all the realizable quotient matrices of perfect 2‐colorings for odd v. © 2012 Wiley Periodicals, Inc. J. Combin. Designs 21: 232–252, 2013
Simple and efficient automated radiosynthesis of 2‐18F‐fluoropropionic acid using solid‐phase extraction cartridges purification
Authors: Hongliang W. , Kongzhen H. , Ganghua T. , Tingting H. , Xiang Liang
Published: July 2012

2‐18F‐Fluoropropionic acid (18F‐FPA), a fluorinated analog of 11C‐acetate, shows great potential for positron emission tomography (PET) imaging of prostate cancer. The present study reports a simple automated synthesis using cartridges purification, which affords 18F‐FPA suitable for human use. Automated synthesis of 18F‐FPA was performed using two‐step one‐pot synthesis procedure, consisting of [18F]fluorination of methyl‐2‐bromopropionate, hydrolysis with sodium hydroxide, and purification with a series of commercial solid‐phase extraction cartridges instead of a high‐performance liquid chromatography system. Automated synthesis of 18F‐FPA was also carried out via the on‐column hydrolysis on the HLB cartridges, using a similar procedure to the automated synthesis of 18F‐fluoro‐2‐deoxy‐ d‐glucose (18F‐FDG). Using one‐pot procedures on the commercial modified PET‐MF‐2V‐IT‐I synthesizer, the final 18F‐FPA solution could be obtained with high uncorrected radiochemical yields (>35%) and radiochemical purity (>95%). For the on‐column hydrolysis procedure, the uncorrected radiochemical yield of 18F‐FPA was 46 ± 7% (n = 5, based on [18F]fluoride) within 36 min and the radiochemical purity was above 95% with the specific activity of 40 GBq/µmol. Automated synthesis of 18F‐FPA by on‐column hydrolysis procedure is similar to the 18F‐FDG synthesis, and it can easily be applied to the automated synthesis of 18F‐FPA on the commercial 18F‐FDG synthesizer. Copyright © 2012 John Wiley & Sons, Ltd.
Comparison of 0.5M gadoterate and 1.0M gadobutrol in peripheral MRA: A prospective, single‐center, randomized, crossover, double‐blind study
Authors: Haneder Stefan , Attenberger Ulrike I. , Schoenberg Stefan O. , Loewe Christian , Arnaiz Javier , Michaely Henrik J.
Published: July 2012

Purpose:

To evaluate the diagnostic efficacy of macrocyclic paramagnetic gadolinium (Gd) chelates gadoterate (0.5 mmol/mL) and gadobutrol (1.0 mmol/mL) for the diagnosis of clinically significant abdominal/lower limb arterial diseases at 3.0T.

Materials and Methods:

This study was conducted as a prospective, single‐center, randomized, double‐blind, intraindividual study comparing single dose (0.1 mmol/kg) gadoterate enhanced‐MRA (magnetic resonance angiography) with gadobutrol enhanced‐MRA at 3.0T for their diagnostic potential in patients with peripheral artery disease. A total of 20 patients were included in this trial.

Results:

Fourteen patients were eligible for the final efficacy analysis. The overall image quality (excellent/more than adequate) was better rated with gadoterate than with gadobutrol (100% vs. 78.6%, 100% vs. 92.9%, 100% vs. 85.7%, 100% vs. 85.7% for readers 1, 2, 3, 4, respectively). Diagnostic confidence was rated high/excellent in 100% (readers 1, 2, and 3) and 92.9% (reader 4) with gadoterate compared to 92.9% (readers 1 and 2) and 85.7% (readers 3 and 4) with gadobutrol. Higher signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) values were obtained for gadobutrol compared to gadoterate (26.1/23.4, P = 0.01, and 22.7/20.2, P = 0.01). For the secondary criteria, no differences between groups were reported. No adverse events were reported.

Conclusion:

Gadobutrol yielded significantly higher SNR/CNR while gadoterate was better rated in terms of overall image quality and diagnostic confidence (P > 0.05). J. Magn. Reson. Imaging 2012;36:1213–1221. © 2012 Wiley Periodicals, Inc.
1H‐nuclear magnetic resonance‐based metabonomic analysis of brain in rhesus monkeys with morphine treatment and withdrawal intervention
Authors: Deng Yi , Bu Qian , Hu Zhengtao , Deng Pengchi , Yan Guangyan , Duan Jiachuan , Hu Chunyan , Zhou Jiaqing , Shao Xue , Zhao Jinxuan , Li Yan , Zhu Ruiming , Zhao Yinglan , Cen Xiaobo
Published: July 2012

Comprehensive cerebral metabolites involved in morphine dependence have not been well explored. To gain a better understanding of morphine dependence and withdrawal therapy in a model highly related to humans, metabolic changes in brain hippocampus and prefrontal cortex (PFC) of rhesus monkeys were measured by 1H‐nuclear magnetic resonance spectroscopy, coupled with partial least squares and orthogonal signal correction analysis. The results showed that concentrations of myoinositol (M‐Ins) and taurine were significantly reduced, whereas lactic acid was increased in hippocampus and PFC of morphine‐dependent monkeys. Phosphocholine and creatine increased in PFC but decreased in hippocampus after chronic treatment of morphine. Moreover, N‐acetyl aspartate (NAA), γ‐aminobutyric acid, glutamate, glutathione, methionine, and homocysteic acid also changed in these brain regions. These results suggest that chronic morphine exposure causes profound disturbances of neurotransmitters, membrane, and energy metabolism in the brain. Notably, morphine‐induced dysregulations in NAA, creatine, lactic acid, taurine, M‐Ins, and phosphocholine were clearly reversed after intervention with methadone or clonidine. Our study highlights the potential of metabolic profiling to enhance our understanding of metabolite alteration and neurobiological actions associated with morphine addiction and withdrawal therapy in primates. © 2012 Wiley Periodicals, Inc.