bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy and precision of vessel area assessment: Manual versus automatic lumen delineation based on full‐width at half‐maximum
Authors: Merkx Maarten A.G. , Bescós Javier Oliván , Geerts Liesbeth , Bosboom E. Mariëlle H. , van de Vosse Frans N. , Breeuwer Marcel
Published: July 2012

Purpose:

To evaluate the accuracy and precision of manual and automatic blood vessel diameter measurements, a quantitative comparison was conducted, using both phantom and clinical 3D magnetic resonance angiography (MRA) data. Since diameters are often manually measured, which likely is influenced by operator dependency, automatic lumen delineation, based on the full‐width at half‐maximum (FWHM), could improve these measurements.

Materials and Methods:

Manual and automatic diameter assessments were compared, using MRA data from a vascular phantom (geometry obtained with μCT) and clinical MRA data. The diameters were manually assessed by 15 MRA experts, using both caliper and contour tools. To translate the experimental results to clinical practice, the precision obtained using phantom data was compared to the precision obtained with clinical data.

Results:

A diameter error <10% was obtained with resolutions above 2, 3, and 5 pixels/diameter for the automatic FWHM, contour, and caliper methods, respectively. Using phantom data, precision of the manual methods was low (error >20%), even at high resolutions, while precision for the automatic method was high (error <3%) when using more than 2 pixels/diameter. A similar trend was found with clinical data.

Conclusion:

The results obtained clearly demonstrate improvement in the accuracy and precision of vessel diameter measurements with use of the automatic FWHM‐based method. J. Magn. Reson. Imaging 2012;36:1186–1193. © 2012 Wiley Periodicals, Inc.
Accelerated 3D MERGE carotid imaging using compressed sensing with a hidden markov tree model
Authors: Makhijani Mahender K. , Balu Niranjan , Yamada Kiyofumi , Yuan Chun , Nayak Krishna S.
Published: July 2012

Purpose:

To determine the potential for accelerated 3D carotid magnetic resonance imaging (MRI) using wavelet based compressed sensing (CS) with a hidden Markov tree (HMT) model.

Materials and Methods:

We retrospectively applied HMT model‐based CS and conventional CS to 3D carotid MRI data with 0.7 mm isotropic resolution from six subjects with known carotid stenosis (12 carotids). We applied a wavelet‐tree model learned from a training database of carotid images to improve CS reconstruction. Quantitative endpoints such as lumen area, wall area, mean and maximum wall thickness, plaque calcification, and necrotic core area were measured and compared using Bland–Altman analysis along with image quality.

Results:

Rate‐4.5 acceleration with HMT model‐based CS provided image quality comparable to that of rate‐3 acceleration with conventional CS and fully sampled reference reconstructions. Morphological measurements made on rate‐4.5 HMT model‐based CS reconstructions were in good agreement with measurements made on fully sampled reference images. There was no significant bias or correlation between mean and difference of measurements when comparing rate 4.5 HMT model‐based CS with fully sampled reference images.

Conclusion:

HMT model‐based CS can potentially be used to accelerate clinical carotid MRI by a factor of 4.5 without impacting diagnostic quality or quantitative endpoints. J. Magn. Reson. Imaging 2012;36:1194–1202. © 2012 Wiley Periodicals, Inc.
MR angiography of carotid artery aneurysms in a porcine model at 3 tesla: Comparison of two different macrocyclic gadolinium chelates and of dynamic and conventional techniques
Authors: Wuesten Oliver , Morelli John N. , Miller Matthew W. , Tuzun Egemen , Lenox Mark W. , Fossum Theresa W. , Trelles Miguel , Cotes Claudia , Krombach Gabriele A. , Runge Val M.
Published: July 2012

Purpose:

To evaluate the differences in image quality of two macrocyclic gadolinium‐based contrast agents, gadobutrol and gadoterate meglumine, using time‐resolved, contrast‐enhanced MR angiography (CE‐MRA) in a porcine carotid artery aneurysm model and to compare image quality between dynamic and conventional, single acquisition CE‐MRA.

Materials and Methods:

Bilateral carotid aneurysms were created surgically in this Institutional Animal Care and Use Committee approved study. Dynamic CE‐MRA studies optimized for high temporal resolution were performed at 3 Tesla. Scans using equivalently dosed (on a per mmol basis) gadobutrol and gadoterate meglumine were compared qualitatively and quantitatively in terms of contrast‐to‐noise ratio (CNR). Higher spatial resolution dynamic and conventional CE‐MRA were also compared.

Results:

N = 16 aneurysms were assessed. Qualitative evaluation of dynamic CE‐MRA scans demonstrated a preference for gadobutrol over gadoterate meglumine. Significantly higher aneurysm CNR was found with gadobutrol (133 ± 44) versus gadoterate meglumine, the latter at both equivalent and double injection rates (94 ± 35 and 102 ± 38). In a blinded assessment, conventional CE‐MRA was preferred qualitatively when compared with dynamic CE‐MRA. However, dynamic CE‐MRA was generally capable of providing diagnostic image quality.

Conclusion:

Gadobutrol is preferred to gadoterate meglumine for high temporal resolution dynamic CE‐MRA, a fact with important clinical implications for low dose CE‐MRA protocols in patients at risk for nephrogenic systemic fibrosis. Conventional high resolution CE‐MRA provides superior image quality when compared with dynamic CE‐MRA. J. Magn. Reson. Imaging 2012;36:1203–1212. © 2012 Wiley Periodicals, Inc.
MR proton spectroscopy for myocardial lipid deposition quantification: A quantitative comparison between 1.5T and 3T
Authors: Venkatesh Bharath Ambale , Lima Joao A.C. , Bluemke David A. , Lai Shenghan , Steenbergen Charles , Liu Chia‐Ying
Published: July 2012

Purpose:

To evaluate 3T magnetic resonance spectroscopy (MRS)‐derived myocardial fat‐signal fractions in comparison with those from 1.5T MRS.

Materials and Methods:

We conducted phantom, ex vivo and in vivo myocardial specimen evaluations at both 1.5T and 3T using 1H‐MRS. A phantom with nine fat‐water emulsions was constructed to assess the accuracy of the spectroscopy measurements. Ex vivo spectroscopy data were acquired in 70 segments from 21 autopsy heart slices. In vivo spectroscopy data were acquired in the interventricular septum from 22 human volunteers.

Results:

Phantom experiments demonstrated that 1.5T and 3T measurements were highly correlated with the reference values (r = 0.78, P < 0.05). The ex vivo and in vivo experiments demonstrated an increase in signal‐to‐noise ratio (SNR) of 45 ± 73% and 76 ± 72% at 3T compared to 1.5T (P < 0.05). The mean fat‐signal fraction was similar at 3T and 1.5T (1.11 ± 1.18 vs. 1.00 ± 1.09, respectively, P = NS) in ex vivo studies but were significantly different in the in vivo studies (2.47 ± 1.46 vs. 1.56 ± 1.34, P < 0.05). The fat‐signal fractions from 3T and 1.5T correlated fairly well in all experiments.

Conclusion:

3T MRS has significantly greater SNR and could potentially be more accurate as compared to 1.5T for quantification of myocardial fat fraction in in vivo studies. J. Magn. Reson. Imaging 2012;36:1222–1230. © 2012 Wiley Periodicals, Inc.
Extension of the intravoxel incoherent motion model to non‐gaussian diffusion in head and neck cancer
Authors: Lu Yonggang , Jansen Jacobus F.A. , Mazaheri Yousef , Stambuk Hilda E. , Koutcher Jason A. , Shukla‐Dave Amita
Published: July 2012

Purpose:

To extend the intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) model to restricted diffusion and to simultaneously quantify the perfusion and restricted diffusion parameters in neck nodal metastases.

Materials and Methods:

The non‐Gaussian (NG)‐IVIM model was developed and tested on diffusion‐weighted MRI data collected on a 1.5‐Tesla MRI scanner from eight patients with head and neck cancer. Voxel‐wise parameter quantification was performed by using a noise‐rectified least‐square fitting method. The NG‐IVIM, IVIM, Kurtosis, and ADC (apparent diffusion coefficient) models were used for comparison. For each voxel, within the metastatic node, the optimal model was determined using the Bayesian Information Criterion. The voxel percentage preferred by each model was calculated and the optimal model map was generated. Monte Carlo simulations were performed to evaluate the accuracy and precision dependency of the new model.

Results:

For the eight neck nodes, the range of voxel percentage preferred by the NG‐IVIM model was 2.3–79.3%. The optimal modal maps showed heterogeneities within the tumors. The Monte Carlo simulations demonstrated that the accuracy and precision of the NG‐IVIM model improved by increasing signal‐to‐noise ratio and b value.

Conclusion:

The NG‐IVIM model characterizes perfusion and restricted diffusion simultaneously in neck nodal metastases. J. Magn. Reson. Imaging 2012;36:1088–1096. © 2012 Wiley Periodicals, Inc.
Use of MMP‐8 and MMP‐9 to assess disease severity in children with viral lower respiratory tract infections
Authors: Brand Kim H. , Ahout Inge M.L. , de Groot Ronald , Warris Adilia , Ferwerda Gerben , Hermans Peter W.M.
Published: July 2012

Matrix metalloproteinases (MMPs) play an important role in respiratory inflammatory diseases, such as asthma and chronic obstructive pulmonary disease. It was hypothesized that MMP‐8 and MMP‐9 may function as biological markers to assess disease severity in viral lower respiratory tract infections in children. MMP‐8 and MMP‐9 mRNA expression levels in peripheral blood mononuclear cells (PBMCs) and granulocytes obtained in both the acute and recovery phase from 153 children with mild, moderate, and severe viral lower respiratory tract infections were determined using real‐time PCR. In addition, MMP‐8 and MMP‐9 concentrations in blood and nasopharyngeal specimens were determined during acute mild, moderate, and severe infection, and after recovery using ELISA. Furthermore, PBMCs and neutrophils obtained from healthy volunteers were stimulated with RSV, LPS (TLR4 agonist), and Pam3Cys (TLR2 agonist) in vitro. Disease severity of viral lower respiratory tract infections in children is associated with increased expression levels of the MMP‐8 and MMP‐9 genes in both PBMCs and granulocytes. On the contrary, in vitro experiments showed that MMP‐8 and MMP‐9 mRNA and protein expression in PBMCs and granulocytes is not induced by stimulation with RSV, the most frequent detected virus in young children with viral lower respiratory tract infections. These data indicate that expression levels of the MMP‐8 and MMP‐9 genes in both PBMCs and neutrophils are associated with viral lower respiratory tract infections disease severity. These observations justify future validation in independent prospective study cohorts of the usefulness of MMP‐8 and MMP‐9 as potential markers for disease severity in viral respiratory infections. J. Med. Virol. 84:1471–1480, 2012. © 2012 Wiley Periodicals, Inc.
Dynamics of urinary polyomavirus shedding in healthy adult women
Authors: Kling Courtney L. , Wright Alexandra T. , Katz Sophie E. , McClure Gloria B. , Gardner J. Suzette , Williams Jason T. , Meinerz Natalie M. , Garcea Robert L. , Vanchiere John A.
Published: July 2012

The hypothesis was examined that physiologic variation of estrogen concentrations during the menstrual cycle can provoke BK virus (BKV) excretion. BKV and JCV viral loads were determined in urine specimens obtained almost daily from 20 healthy, non‐pregnant women over 2 months. Asymptomatic urinary shedding of BKV was observed in 123 (12.0%) of 1,021 specimens from 11 (55%) study subjects. Two subjects excreted JCV in their urine, with one subject excreting detectable JCV in all urine specimens. Analysis of 36 complete menstrual cycles revealed no difference in the prevalence of BKV excretion between pre‐ovulatory and post‐ovulatory phases of the menstrual cycle. The unexpected day‐to‐day variability in BKV excretion suggests that as yet unidentified factors may contribute to the periodic shedding of BKV by healthy women. J. Med. Virol. 84:1459–1463, 2012. © 2012 Wiley Periodicals, Inc.
Oral health profile in patients infected with HTLV‐1: Clinical findings, proviral load, and molecular analysis from HTLV‐1 in saliva
Authors: Lins Liliane , de Carvalho Victor José Uchoa , de Almeida Rego Filipe Ferreira , Azevedo Rochele , Kashima Simone , Gallazi Viviana Nilla Olavarria , Xavier Marcia Tosta , Galvão‐Castro Bernardo , Alcantara Luiz Carlos Junior
Published: July 2012

Human T‐lymphotropic virus type 1 (HTLV‐1) is associated with adult T‐cell leukemia (ATL) and HTLV‐1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) and has also been implicated in several disorders, including periodontal disease. The proviral load is an important biological marker for understanding HTLV‐1 pathogenesis and elucidating whether or not the virus is related to the clinical manifestation of the disease. This study describes the oral health profile of HTLV‐1 carriers and HAM/TSP patients in order to investigate the association between the proviral load in saliva and the severity of the periodontal disease and to examine virus intra‐host variations from peripheral blood mononuclear cells and saliva cells. It is a cross‐sectional analytical study of 90 individuals carried out from November 2006 to May 2008. Of the patients, 60 were HTLV‐1 positive and 30 were negative. Individuals from the HTLV‐1 positive and negative groups had similar mean age and social‐economic status. Data were analyzed using two available statistical software packages, STATA 8.0 and SPSS 11.0 to conduct frequency analysis. Differences of P < 0.05 were considered statistically significant. HTLV‐1 patients had poorer oral health status when compared to seronegative individuals. A weak positive correlation between blood and saliva proviral loads was observed. The mean values of proviral load in blood and saliva in patients with HAM/TSP was greater than those in HTLV‐1 carriers. The HTLV‐1 molecular analysis from PBMC and saliva specimens suggests that HTLV‐1 in saliva is due to lymphocyte infiltration from peripheral blood. A direct relationship between the proviral load in saliva and oral manifestations was observed. J. Med. Virol. 84:1428–1436, 2012. © 2012 Wiley Periodicals, Inc.
Pre‐ and post‐pandemic prevalence of antibodies to the 2009 pandemic influenza A (H1N1) virus in Austrian adults
Authors: Poeppl W. , Poeppl G. , Hunger M. , Tobudic S. , Winkler H. , Faas A. , Mooseder G. , Burgmann H.
Published: July 2012

Antibody prevalence to the 2009 pandemic influenza A (H1N1) virus was determined in a sample of the Austrian population to assess the post‐pandemic seropositivity rate, the infection attack rate, and the proportion of subclinical infections during the 2009/2010 influenza pandemic in Austrian adults. A total of 480 sera from individuals aged between 18 and 57 years from all nine federal states of Austria were collected between April and June 2010. Information on demographic characteristics, vaccination history, and history of suspected or verified influenza virus infection was ascertained. Antibodies were determined using a commercial ELISA and compared with 80 age‐matched adult sera collected before the pandemic began. The overall seropositivity rate was 28% and was highest among young adults aged 18–29 years, followed by adults aged 50–57 years. Among seropositive unvaccinated individuals, infection was asymptomatic in more than 80%. Extrapolation to the overall Austrian adult population indicates that more than 1.3 million persons aged 18–57 years became infected in 2009. Compared with the pre‐pandemic seropositivity rate, the infection rate was highest among young adults but low in those aged 30–57 years. Among 69 individuals previously vaccinated with the 2009 pandemic influenza A (H1N1) virus, 71% had specific antibodies. The study demonstrates that infection rates based on surveillance of clinical cases considerably underestimated the infection attack rate during the 2009 H1N1 pandemic in Austria and that vaccination against this virus elicited long‐lasting seropositivity in more than 70% of adults. J. Med. Virol. 84:1331–1334, 2012. © 2012 Wiley Periodicals, Inc.
Case report: Management and HBV sequencing in a patient co‐infected with HBV and HIV failing tenofovir
Authors: Mikulska Małgorzata , Taramasso Lucia , Giacobbe Daniele Roberto , Caligiuri Patrizia , Bruzzone Bianca , Di Biagio Antonio , Viscoli Claudio
Published: July 2012

Nucleos(t)ide analogs such as tenofovir, lamivudine, or emtricitabine are active against both HBV and HIV. Tenofovir confers potent and durable HBV‐DNA suppression but the best strategy in case of resistance of HBV to tenofovir remains unknown. A case of a 22‐year‐old patient with co‐infection with HBV and HIV transmitted perinatally is reported. After prolonged and intermittent treatment of HIV with lamivudine and tenofovir, HBV became resistant to lamivudine. Subsequently, clinical resistance to tenofovir occurred, manifesting as HBV‐DNA breakthrough. The non‐compliance was reasonable excluded and HIV‐RNA remained constantly suppressed. Entecavir (1 mg daily) was added and the combination therapy resulted in a rapid and continuous suppression of HBV‐DNA for over 12 months. The treatment was well‐tolerated and safe. No known mutations, such as rtA181T/V associated with rtN236T or A194T that are associated with reduced susceptibility or resistance to tenofovir were detected. However, a unique and complex HBV substitution pattern was found: with a development of rtR192PR mutation at the time of virological failure. Adding entecavir to failing therapy with tenofovir and emtricitabine was feasible, well‐tolerated and resulted in virological success. The rtR192PR, which is located in the B domain near the rtA194T, occurring in a context of a very complex substitutions patterns, might be associated with resistance to tenofovir. J. Med. Virol. 84:1340–1343, 2012. © 2012 Wiley Periodicals, Inc.
Molecular and epidemiological features of gastroenteritis outbreaks involving genogroup I norovirus in Victoria, Australia, 2002–2010
Authors: Bruggink Leesa D. , Oluwatoyin Osunneye , Sameer Rizmina , Witlox Kristie J. , Marshall John A.
Published: July 2012

GI noroviruses are relatively rare and systematic studies of the molecular epidemiology of GI norovirus outbreaks are lacking. The current study examined the molecular virology of GI norovirus outbreaks in Victoria, Australia (2002–2010). Of 1,617 norovirus outbreaks identified, 69 (4.3%) were associated with GI norovirus alone, 1,540 (95.2%) with GII norovirus alone and 8 (0.5%) with GI + GII. Some differences between GI and GII outbreak epidemiology were found. GI outbreaks peaked in the 2‐month period November/December whereas GII outbreaks peaked in the 2‐month period September/October and GI norovirus outbreaks were significantly more common in non‐healthcare settings (37.7%) than GII outbreaks (9.5%). ORF 1/ORF 2 genotypes found in the 69 outbreaks involving GI norovirus alone were: GI.2/GI.2, 7 outbreaks; GI.2/GI.6, 18 outbreaks; GI.3b/GI.3, 14 outbreaks; GI.4/GI.4, 21 outbreaks; GI.8/GI.8, one outbreak; GI.d/GI.3, four outbreaks; and GI.e/GI.13, one outbreak. The current study appears to be the first to have identified the recombinant form, GI.2/GI.6. Whereas GI.2/GI.6 and GI.3b/GI.3 outbreaks occurred with equal frequency in both healthcare and non‐healthcare settings, GI.4/GI.4 occurred predominantly in healthcare settings. GI ORF 1/ORF 2 genotypes found in the eight outbreaks involving GI + GII norovirus were GI.2/GI.6, GI.3b/GI.3, and GI.4/GI.4, indicating GI genotypes in GI + GII outbreaks were similar to those found in outbreaks involving GI alone. Apparent differences in the evolution of different GI genotypes were noted. GI.2/GI.2, GI.2/GI.6, and GI.4/GI.4 strains tended to undergo periodic shifts in nucleotide sequence whereas various GI.3b/GI.3 strains tended to circulate simultaneously. J. Med. Virol. 84:1437–1448, 2012. © 2012 Wiley Periodicals, Inc.
Development of quantitative RT‐PCR assays for detection of three classes of HHV‐6B gene transcripts
Authors: Ihira Masaru , Enomoto Yoshihiko , Kawamura Yoshiki , Nakai Hidetaka , Sugata Ken , Asano Yoshizo , Tsuzuki Motohiro , Emi Nobuhiko , Goto Tatsunori , Miyamura Koichi , Matsumoto Kimikazu , Kato Koji , Takahashi Yoshiyuki , Kojima Seiji , Yoshikawa Tetsushi
Published: July 2012

The monitoring of active human herpesvirus 6 (HHV‐6) B infection is important for distinguishing between the reactivation and latent state of the virus. The aim of this present study is to develop a quantitative reverse transcription polymerase chain reaction (RT‐PCR) assay for diagnosis of active viral infection. Primers and probes for in house quantitative RT‐PCR methods were designed to detect the three kinetic classes of HHV‐6B mRNAs (U90, U12, U100). Stored PBMCs samples collected from 10 patients with exanthem subitum (primary HHV‐6B infection) and 15 hematopoietic stem cell transplant recipients with HHV‐6B reactivation were used to evaluate reliability for testing clinical samples. Excellent linearity was obtained with high correlation efficiency between the diluted RNA (1–100 ng/reaction) and Ct value of each gene transcript. The U90 and U12 gene transcripts were detected in all of the peripheral blood mononuclear cells (PBMCs) samples collected in acute period of primary HHV‐6B infection. Only one convalescent PBMCs sample was positive for the U90 gene transcript. Additionally, the reliability of HHV‐6B quantitative RT‐PCRs for diagnosis of viral reactivation in hematopoietic transplant recipients was evaluated. Relative to virus culture, U90 quantitative RT‐PCR demonstrated the highest assay sensitivity, specificity, positive predictive value, and negative predictive value. Thus, this method could be a rapid and lower cost alternative to virus culture, which is difficult to perform generally, for identifying active HHV‐6B infection. J. Med. Virol. 84:1388–1395, 2012. © 2012 Wiley Periodicals, Inc.
Coping with economic stress: Introduction to the special issue
Authors: Klehe Ute‐Christine , van Vianen Annelies E. M. , Zikic Jelena
Published: July 2012

This special issue presents five papers, four empirical and one conceptual, on how people deal with different forms and stages of economic stress. Three manuscripts address coping with job insecurity in one's regular job or in the context of self‐employment. These papers focus on the multidimensional nature and the development of insecurity over time, personal and social resources, along with organizational interventions that are helpful in minimizing the aversive effects of insecurity. The remaining two papers address respondents' coping with unemployment and factors that may either motivate people to seek help and search for reemployment or that turn unemployed workers into discouraged workers who are giving up in the face of their dire situation. Copyright © 2012 John Wiley & Sons, Ltd.
Development and characterization of an automated high throughput screening method for optimization of protein refolding processes
Authors: Berg Annette , Oelmeier Stefan A. , Kittelmann Jörg , Dismer Florian , Hubbuch Jürgen
Published: July 2012

Optimization of protein refolding parameters by automated, miniaturized, and parallelized high throughput screening is a powerful approach to meet the demand for fast process development with low material consumption. In this study, we validated methods applicable on a standard liquid handling robot for screening of refolding process parameters by dilution of denatured lysozyme in refolding buffer systems. Different approaches for the estimation of protein solubility and folding were validated concerning resolution and compatibility with the robotic system and with the complex buffer and protein structure composition. We established an indirect method to assess soluble lysozyme concentration independent of matrix effects and protein structure varieties by automated separation of aggregated protein, resolubilization, and measurement of absorption at 280 nm. Using this nonspecific solubility assays the correlation between favorable parameters for high active and soluble lysozyme yields were evaluated. An overlap of good refolding buffer compositions was found provided that the redox environment was controlled with redox reagents. In addition, the need to control unfolding conditions like time, temperature, lysozyme, and dithiothreitol concentration was pointed out as different feedstocks resulted in different refolding yields.
Nest success and hatchling survival of American alligators within inland wetlands of east Texas
Authors: Saalfeld David T. , Conway Warren C. , Calkins Gary E.
Published: July 2012

Because of liberalization of American alligator (Alligator mississippiensis) harvest management in Texas, estimates of nest success and hatchling survival for inland populations are essential for long‐term, sustainable population and harvest management. To date, few studies have examined American alligator nest success and hatchling survival. We initiated a 3‐year study from 2006 to 2008 to document alligator nest success and hatchling survival within several wetlands in east Texas. From June 2006 to August 2008, we located 30 nests from 3 wetlands within east Texas, where overall nest success was 44.2% (95% CI = 25.1–63.1%), irrespective of year. Nest circumference and day during the nesting season exerted the greatest influence on nest success. Additionally, from August 2006 to August 2008 we captured, marked, and released 271 hatchling alligators at Little Sandy National Wildlife Refuge, and recaptured an additional 192 hatchling alligators during this time. We estimated yearly apparent survival at 6.0% (95% CI = 2.0–14.6%) for hatchling alligators born in 2006 and 43.0% (95% CI = 28.4–57.8%) for those hatched in 2007. Variation in nest success and hatchling survival was likely attributed to fluctuating water levels and habitat management practices. Alligator harvest regulations need to account for variability in nest success and hatchling survival by including site‐specific estimates of these metrics into harvest models. Failing to account for spatial and temporal variation in nest success and hatchling survival may result in unsustainable harvest and/or overharvest. © 2012 The Wildlife Society.
Overwintering sparrow use of field borders planted as beneficial insect habitat
Authors: Plush Charles J. , Moorman Christopher E. , Orr David B. , Reberg‐Horton Chris
Published: July 2012

Field borders are an effective conservation strategy for providing habitat to overwintering sparrows, and may be a venue through which beneficial insect populations are promoted. However, traditional fallow field borders lack sufficient pollen and nectar sources required to sustain beneficial insect populations; therefore, borders planted to a mix of native prairie flowers and grasses may be needed if increases in beneficial insect populations are desired. Although the value of fallow borders to birds has been established, little is known about bird use of beneficial insect habitats. Using single‐observer transect surveys, we compared overwintering sparrow densities among 4 field border treatments (planted native warm season grasses and prairie flowers, planted prairie flowers only, fallow, and mowed) replicated around 9 organic crop fields from November to March 2009–2010 and 2010–2011. Sparrow densities were 5–10 times lower in mowed borders than in other border treatments in 2009–2010 and 2010–2011, but did not differ among planted and fallow borders in either year. Planted field borders may be a useful conservation practice for providing habitat for both overwintering sparrows and beneficial insects. © 2012 The Wildlife Society.
Epinephrine and phenylephrine pretreatments for preventing postreperfusion syndrome during adult liver transplantation
Authors: Ryu Ho-Geol , Jung Chul-Woo , Lee Hyung-Chul , Cho Youn-Joung
Published: July 2012

Acute hypotension after reperfusion of the liver graft occurs frequently during liver transplantation. A randomized, prospective trial was performed to test the effects of epinephrine and phenylephrine pretreatments for attenuating postreperfusion syndrome (PRS). Ninety-three adult liver recipients were randomly allocated to receive an intravenous bolus of 10 μg of epinephrine, 100 μg of phenylephrine, or normal saline (the control group) at the time of graft reperfusion. The occurrence of PRS, the use of vasoactive drugs, and the postoperative courses were compared. The epinephrine and phenylephrine groups showed PRS less frequently (39% and 48%) than the control group (77%, P = 0.006) as well as higher mean arterial pressures (MAPs) immediately after reperfusion (P < 0.05). An overshoot of MAP was observed in one-third of the pretreated patients with minimal heart rate changes. Only 2 patients in each pretreatment group showed an increase in MAP that was greater than 20% of the baseline value. The intraoperative epinephrine and dopamine requirements were significantly lower in both pretreatment groups. Perioperative laboratory data, postoperative stays, and in-hospital mortality rates were similar for the 3 groups. In conclusion, pretreatment with 10 μg of epinephrine or 100 μg of phenylephrine significantly reduces the occurrence of PRS and vasopressor requirements without immediate or delayed adverse effects in adult liver transplantation. Liver Transpl, 2012. © 2012 AASLD.
Serum C-reactive protein is a useful biomarker for predicting outcomes after liver transplantation in patients with hepatocellular carcinoma
Authors: An Ho Jung , Jang Jeong Won , Bae Si Hyun , Choi Jong Young , Yoon Seung Kew , Lee Myung Ah , You Young Kyoung , Kim Dong Goo , Jung Eun Sun
Published: July 2012

Liver transplantation (LT) is a curative modality for hepatocellular carcinoma (HCC), especially in patients with cirrhosis. However, there are still risks of recurrence. C-reactive protein (CRP), an acute-phase inflammatory reactant that is synthesized by hepatocytes, has been related to the prognosis of various malignancies, including HCC. In this study, we investigated the role of a high CRP level in predicting the posttransplant outcomes of HCC patients. We analyzed 85 patients undergoing LT between August 2000 and July 2010 whose pretransplant serum CRP levels were available. Only 2 patients underwent deceased donor LT, and the remaining patients underwent living donor LT. With 1 mg/dL used as a cutoff value, 27 patients showed high CRP levels (≥1 mg/dL) at the time of LT, and 58 showed low CRP levels (<1 mg/dL). The total bilirubin level, Child-Pugh grade, Model for End-Stage Liver Disease score, maximal tumor size, and frequency of intrahepatic metastasis were significantly higher in the high-CRP group. According to multivariate analyses, HCC beyond the Milan criteria, a high CRP level, and microvascular invasion were related to tumor recurrence, and a high CRP level and microvascular invasion were related to poor overall survival. When a subgroup analysis was performed according to the Milan criteria, a high CRP level was an independent factor for predicting poor outcomes in patients with HCC beyond the Milan criteria (P = 0.02 for recurrence and P < 0.001 for survival) but not in patients with HCC within the criteria. Serum CRP could be considered a useful and cost-effective biomarker for predicting outcomes after LT for HCC, particularly in patients beyond the Milan criteria. Liver Transpl, 2012. © 2012 AASLD.
Reducing the load: The evolution and management of obesity and nonalcoholic steatohepatitis before liver transplantation
Authors: Watt Kymberly D.
Published: July 2012

Key Points

1. Obesity is common in patients with end-stage liver disease of any cause.

2. Obesity is associated with comorbidities that can affect liver transplant candidacy, such as metabolic syndrome (diabetes, hyperlipidemia, and hypertension), cardiovascular disease, pulmonary disorders (related to obstructive sleep apnea), renal dysfunction, and malignancies.

3. Nonalcoholic steatohepatitis is the only indication for transplantation that is increasing in frequency, and it may soon become the leading indication.

4. There is no set body mass index above which liver transplantation is contraindicated. Transplant candidacy and outcomes depend on the cumulative comorbidities of the individual patient.

5. Weight loss is an important component of metabolic syndrome management and is recommended before liver transplantation.

6. Bariatric surgery may be considered in carefully selected patients with well-compensated cirrhosis but is not recommended in patients with decompensated cirrhosis. Liver Transpl 18:S-S, 2012. © 2012 AASLD.
Efficacy of antiviral therapy for hepatitis C after liver transplantation with cyclosporine and tacrolimus: A systematic review and meta-analysis
Authors: Rabie Rania , Mumtaz Khalid , Renner Eberhard L.
Published: July 2012

Cyclosporine A (CSA), but not tacrolimus (TAC), inhibits hepatitis C virus (HCV) replication in vitro. Clinical reports on the efficacy of interferon-α (IFNα)–based antiviral therapy (AVT) for recurrent HCV after liver transplantation (LT) with CSA and TAC are conflicting. Our aim was to assess whether AVT for recurrent HCV after LT is more effective with CSA or TAC. We performed an electronic database search (1995-2012) and a manual abstract search (2005-2012). The a priori defined eligibility criteria included the use of AVT for recurrent HCV with IFN (standard or pegylated) and ribavirin and the reporting of sustained virological response (SVR) rates with CSA and TAC (the primary outcome). Two authors identified and extracted data independently. Dichotomous data were expressed as relative risks (RRs) and 95% confidence intervals (CIs) with a random effects model. In all, 5058 references were retrieved, and 1 randomized controlled trial (RCT) and 17 observational studies (13 full-text articles) met the eligibility criteria; the meta-analysis was based on the latter studies. The pooled SVR rates were 42% (395/945) with CSA and 35% (471/1364) with TAC (RR = 1.18, 95% CI = 1.00-1.39, P = 0.05). Although the pooled data contained significant heterogeneity (I
2 = 45%, P = 0.02), the SVR rates in the RCT were comparable (39% with CSA and 35% with TAC). Limiting the analysis to the 7 studies reporting on 40 or more patients in each group (with 1634 patients in all) favored CSA (RR = 1.23, 95% CI = 1.09-1.38, P < 0.001), and heterogeneity disappeared (I
2 = 0%, P = 0.62). In conclusion, IFN-based AVT for recurrent HCV after LT seems marginally more effective with CSA versus TAC; the study heterogeneity, however, limits firm conclusions. Liver Transpl 19:36–48, 2013. © 2012 AASLD.
Eigenvalue and singular value estimates for integral operators: a unifying approach
Authors: Menegatto V. A. , Oliveira C. P.
Published: July 2012

We consider integral operators generated by square integrable kernels on an abstract measure space. Under smoothness assumptions defined by the action of a convenient multiplier‐like operator on the kernel, we deduce decay rates for either the eigenvalues or the singular values of the integral operator. The setting is an abstract framework which encompasses classical cases that have appeared in different sources in the literature.
Cryogenic forming of AA7075 by Equal‐Channel Angular Pressing
Authors: Fritsch S. , Scholze M. , Wagner M.F.‐X.
Published: July 2012

As high strength aluminum alloys are generally hard to deform, the application of conventional severe plastic deformation methods, which in principle allow the generation of ultra fine grained microstructures and increasing strength, is limited. In this study, cryogenic ECAP deformation as an alternative approach to deform a 7075 alloy is explored. Here, a tool with an internal angle of 90° is used. We demonstrate that cryogenic ECAP (followed by suitable heat treatments) results in increases of the degree of deformation, strength and ductility. Moreover, we present first results on the effect of cryogenic ECAP on microstructural evolution and mechanical properties of the 7075 alloy that demonstrate the potential of cryogenic forming to produce improved properties of high‐strength aluminum alloys.
Influence of the process parameters on the forming result in indirect extrusion of semi‐finished products of aluminum‐magnesium compounds
Authors: Neugebauer R. , Porstmann S. , Glaß R. , Popp M. , Zachäus R.
Published: July 2012

Aufbauend auf vorangegangenen Erstversuchen zur Herstellung von Al‐Mg‐Verbundhalbzeugen durch indirektes Strangpressen [9] wurde das Untersuchungsprogramm erweitert und vertieft. Neben der Variation von Prozessparametern werden Analogversuche zur Untersuchung intermetallischer Phasen vorgestellt. In den erweiterten Versuchsreihen werden der Einfluss einer neuen Schmiermittelkombination, der Ausgangstemperatur des Pressbolzens und einer integrierten Abkühlstrecke auf die Verbundqualität und Strangoberfläche untersucht. Ein zentraler Aspekt der Verbunderzeugung ist die Ausbildung intermetallischer Phasen. Zur vertieften Untersuchung von Entstehung, Verteilung und Eigenschaften dieser Phasen wurden Verbunde durch Diffusionslöten erzeugt. Mit diesem Verfahren werden die Effekte der inhomogenen Oberflächenvergrößerung, die bei der umformenden Verbunderzeugung auftreten können, ausgeschlossen. Weiterhin ist eine wesentlich leichtere Einbringung von Zwischenschichten möglich, die erheblichen Einfluss auf die intermetallische Phasenbildung haben. Die Reproduzierbarkeit der durch indirektes Strangpressen hergestellten Stoffverbunde zwischen der untersuchten Aluminium‐ und Magnesiumlegierung kann gewährleistet werden. Das Prozessfenster, in dem vollständig verbundene Stranghalbzeuge entstehen, ist sehr klein. Die Gewährleistung gleichbleibender tribologischen Verhältnisse während der Umformung ist dabei von besonderer Bedeutung.
Micro‐ and macroelectrochemical investigations of the corrosion behavior of an Al/Mg compound
Authors: Händel M. , Nickel D. , Alisch G. , Lampke T.
Published: July 2012

The motivation for the application of Al/Mg compounds is to achieve significant progress towards lightweight structures. However, they are not used frequently because of the high corrosion susceptibility of magnesium. For this reason, knowledge of the corrosion behavior and the protection against corrosion are essential for the safe use in the component. This article contains results concerning the corrosion characteristics of the unprotected and the plasma‐electrolytically anodized Al/Mg compound. At the same time, the usefulness of microelectrochemical corrosion studies is demonstrated, given that it is possible to check coatings with regard to their permeability due to the high sensitivity of this method. It was found that the coating significantly enhances the corrosion resistance.
Material properties and formability of extruded Al‐Mg compounds as a function of temperature
Authors: Feuerhack A. , Binotsch C. , Awiszus B. , Wolff A. , Brämer C. , Stockmann M.
Published: July 2012

Die ersten Untersuchungen der hydrostatisch stranggepressten Al‐Mg Verbunde als Halbzeuge für Folgeprozesse wie Gesenkschmieden verdeutlichen das große Potenzial hybrider Werkstoffverbunde. Die experimentellen Analysen ergaben, dass die Grenzschicht ein hohes Umformvermögen aufweist. Mit verschiedenen Gesenkschmiedeoperationen konnten Umformgrade von 1,50 erreicht werden, ohne dass eine Schädigung in der Grenzschicht auftrat. Die numerischen Untersuchungen ergaben keine signifikanten Dehnungsunterschiede in der Grenzschicht und verdeutlichen somit die Stabilität der Zwischenschicht. Materialkennwerte der stranggepressten Einzelwerkstoffe wurden für unterschiedliche Temperaturen und Umformungsgeschwindigkeiten bestimmt, um zukünftig noch präzisere Simulationen zu ermöglichen.
Fatigue crack propagation in an ECAP‐processed aluminium alloy – influence of shear plane orientation
Authors: Hockauf K. , Hockauf M. , Wagner M. F.‐X. , Lampke T. , Halle T.
Published: July 2012

In this work, the orientation‐dependent fatigue crack propagation behaviour in an ECAP‐processed aluminium alloy is investigated. For a bimodal condition with elongated structures as well as for a homogeneous condition with equiaxed ultrafine grains, the tendency for crack path deviation was evaluated for different sample orientations. In the case of elongated structures, the crack path is deflected towards the elongation plane. However, the angle of deviation differs, depending on whether the fatigue crack propagation rate was in the near‐threshold and lower Paris‐Erdogan regime (higher angle of deviation) or the upper Paris‐Erdogan regime (smaller angle of deviation). Especially in the near‐threshold region, the crack path deviation is linked to higher crack growth rates when compared to ideally straight crack propagation. This effect can be explained by the effects of processing‐induced damage and local stress fields along the elongated structures.
Hypothesis for dimensioning of selected ultra‐fine grained aluminium bolts
Authors: Gröber D. , Georgi W. , Leidich E. , Mayr P.
Published: July 2012

Bei der angestrebten Energie‐ und Ressourceneinsparung in zukünftigen Leichtbaukonzepten spielen lösbare mechanische Verbindungen aus Aluminium eine zunehmende Rolle. Großes Potenzial hinsichtlich der Zuverlässigkeit besitzen dabei Schrauben aus ECAP‐iertem Aluminium. Die zur Auslegung notwendigen mechanischen Eigenschaften sind noch nicht ausreichend erforscht. Im vorliegenden Artikel werden daher aktuelle Ergebnisse von Schwingfestigkeits‐ und Betriebsfestigkeitsuntersuchungen von Aluminiumschrauben M10x50 aus den Werkstoffen EN‐AW 6082 und EN AW 6082 ECAP‐iert optimiert vorgestellt und mit denen der Serienschraube aus EN‐AW 6056 verglichen. Diese Erkenntnisse werden zur Beschreibung der Versagensursachen herangezogen und am Beispiel einer Fehlerbaumanalyse dargestellt.
Influencing the residual stresses in the surface layer by use of appropriate cutting parameters and tool geometries in turning of aluminium matrix composites
Authors: Schubert A. , Nestler A. , Mehner T.
Published: July 2012

Surface properties of components often determine their proper functioning. More complex and increasing demands on operational systems require detailed understanding in the influence of machining on the surface layer. Besides surface structure, residual stresses are very important, especially for dynamically loaded boundary surfaces. But, for cutting of modern light weight construction materials like aluminium matrix composites there is insufficient information concerning residual stresses. On this account, experimental investigations in turning of SiC particle reinforced aluminium matrix composites with different cutting parameters and tool geometries are presented with the focus on residual stresses. They are determined by X‐ray diffraction analysis. The results show that in general the use of very small feeds, tools with a width of flank wear land of about 100 μm, or with a small corner radius cause high absolute values of the compressive residual stresses. In consequence, knowledge of the relation between machining and the residual stress state of the surface layer allows to selectively induce residual stresses in the surface layer. This can provide, for example, an increase of fatigue strength.
Ultrasound‐assisted resistance soldering of aluminium matrix composites
Authors: Weis S. , Wielage B. , Seehofer C.
Published: July 2012

Für das Fügen der Aluminiumlegierung EN AW‐6012 und des Aluminiummatrix‐Verbundwerkstoffes EN AW‐2017 + 10 Vol.‐% (Al2O3)P mittels des Zinkbasislotes ZnAl4 wird das ultraschallunterstützte Widerstandslöten angewendet. Untersucht werden die Einflussgrößen Anpresskraft, Transformator‐ und Ultraschallleistung sowie die Auswirkung unterschiedlicher Fügeflächengeometrien auf die Verbindungseigenschaften. Als wesentlicher Indikator dient dabei die Verbindungsfestigkeit, welche im 3‐Punkt‐Biegeversuch ermittelt wird.
Teams, Team Motivation, and the Theory of the Firm
Authors: Foss Nicolai J. , Lindenberg Siegwart
Published: July 2012

A concern with teams was central to early attempts to grasp the nature of the firm but fell out of favor in later work. We encourage a return to the emphasis on teams but argue that the idea of teams as central to the nature of the firm needs to be grounded in an appreciation of the importance of We frames and group agency. We use converging insights from evolutionary anthropology, cognitive sociology and psychology and work on team agency to develop such a grounding and link it to the issues of the existence, boundaries, and success of firms. Copyright © 2012 John Wiley & Sons, Ltd.
Free jejunum reconstruction of upper esophageal defects
Authors: Laing Tereze A. , Van Dam Helena , Rakshit Kaushik , Dilkes Mike , Ghufoor Khalid , Patel Hasu
Published: July 2012

The free jejunum has become an important method for reconstructing extensive oncologic defects of the upper esophagus and pharynx. The advantages of a single‐staged reconstruction with a low incidence of morbidity have generally outweighed criticisms such as the requirement for a laparotomy and poor voice quality. The aim of the study was to present the technique and outcomes of free jejunal reconstruction of the upper esophagus in 31 consecutive cases. We reviewed our experience of free jejunal flaps undertaken over a 6‐year period. Our surgical approach, complications, and results of swallow and speech restoration are described. A functional swallow was achieved by 27/31 patients. However, satisfactory voice restoration was seen in only a small proportion of patients. Complications at the donor site occurred in just one patient. The current review confirms the jejunal flap as a reliable reconstructive option with minimal donor site morbidity. © 2012 Wiley Periodicals, Inc. Microsurgery, 2013.
The oblique branch trap in the harvest of the anterolateral thigh myocutaneous flap
Authors: Wong Chin‐Ho
Published: July 2012

A 67‐year‐old man with squamous cell carcinoma underwent reconstruction with a free anterolateral thigh myocutaneous flap. Unroofing the skin perforators found that the skin perforators originated from the oblique branch of the lateral circumflex femoral artery with no connections with the descending branch. Thus, the flap was harvested based on the oblique branch, leaving the descending branch in situ. Reconstruction was completed uneventfully and he had an excellent outcome at 1‐year follow‐up. The anterolateral thigh myocutaneous flap was reputed to be a technically easy flap to harvest. The perforators supplying the skin were visualized and a block of muscle incorporating the perforators harvested with the descending branch of the lateral circumflex femoral artery as the pedicle of the flap. However, not infrequently with this approach, the flap thus harvested has a well‐perfused muscle component, whereas the skin component was not viable. This situation is explained anatomically by the potential occurrence of an alternative pedicle that supplies the anterolateral thigh flap, called the oblique branch of the lateral circumflex femoral artery. Our case presented here was a “classic” intraoperative finding of this potential trap and the importance of defining the anatomy before committing oneself to the harvest by unroofing all the skin perforators was emphasized. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.