bluuebunny/crossref_metadata_2025 huggingface dataset:
IMPROVING FOOD CHOICES AMONG SUPPLEMENTAL NUTRITION ASSISTANCE PROGRAM RECIPIENTS
Authors: You Wen , Mitchell Paul D. , Nayga Rodolfo M.
Published: June 2011

We used a principal–agent framework to examine the feasibility of two proposed modifications to the Supplemental Nutrition Assistance Program with the goal of encouraging healthier food choices among program participants. Specifically, we analyzed two types of contract: a restricted contract and an incentive contract. The restricted contract did not allow the purchase of unhealthy foods with program benefits, but compensated participants by increasing total benefits. The incentive contract provided increased benefits that varied according to the percentage of healthy foods purchased with program benefits. The theoretical results revealed the mechanisms for the two alternative contracts, the conditions under which each would be effective, and the key empirical questions to be examined for future policy analysis. Copyright © 2011 John Wiley & Sons, Ltd.
Identification of high‐risk stage II and stage III colorectal cancer by analysis of MMP‐21 expression
Authors: Wu Tao , Li Yi , Liu Xiaohong , Lu Jianguo , He Xianli , Wang Qing , Li Jipeng , Du Xilin
Published: June 2011

Background

The expression of matrix metalloproteinase‐21 (MMP‐21) has been shown to be elevated in some solid tumor and thought to enhance tumor invasion and metastasis ability. In the present study, we investigated the expression of MMP‐21 and its association with prognosis in stage II and III colorectal cancer.

Methods

MMP‐21 expression was investigated in 286 cases of colorectal cancer by immunohistochemistry assay. Statistical analysis was utilized to evaluate the association of MMP‐21 expression with clinicopathological characters and overall survival of patients with stage II and III colorectal cancer.

Results

MMP‐21 expression was significantly higher in colorectal cancer, compared with that in normal epithelial tissue. And it also correlated with tumor invasion, lymph node metastasis, and distant metastasis of colorectal cancer. MMP‐21 was also proved to be an independent prognostic factor in patients with stage II as well as stage III colorectal cancer. However, no correlations between MMP‐21 expression and patients' age, sex, tumor location, or differentiation status were detected.

Conclusion

These results suggested the potential role of MMP‐21 in the invasion and metastasis process of human colorectal cancer. It could also be a novel molecular marker to predict prognosis of patients with stage II and stage III colorectal cancer. J. Surg. Oncol. 2011; 104:787–791. © 2011 Wiley Periodicals, Inc.
Patients' expectations and success criteria for liver transplantation
Authors: Rodrigue James R. , Hanto Douglas W. , Curry Michael P.
Published: June 2011

Patient-reported outcomes are important to consider when the relative success of liver transplantation (LT) is being evaluated. Our primary objective was to examine the expectations for LT and the criteria for its success across 4 domains of functioning (pain, fatigue, emotional distress, and interference with daily activities) from the perspective of patients who were wait-listed for LT. One hundred four adult patients with a mean wait-list time of 16.5 ± 13 months completed a semistructured interview with a modified version of the Patient-Centered Outcomes Questionnaire (PCOQ). The patients reported moderate usual levels of pain, fatigue, emotional distress, and interference with daily activities (mean rating range = 3.8-6.2), and they attached great importance to improvements in these domains after LT (mean rating range = 7.3-8.0). Patients considered a mean reduction in pain of 33% to be a successful LT outcome. A reduction in fatigue of 56%, a reduction in emotional distress of 44%, and a reduction in interference with daily activities of 54% represented successful LT across these domains. Patients with more severe illness had higher expectations for fatigue (r = −0.30, P = 0.002) and interference with daily activities (r = −0.24, P = 0.015). Cluster and correlational analyses provided support for the validity of the PCOQ with LT patients. Our findings underscore the importance and value of using patient-centered assessments to better understand the ways in which patients prioritize LT outcomes and define transplantation success. Patient-centered assessments have the potential to facilitate provider-patient communication by helping patients to prioritize their goals for LT and make informed choices on the basis of those priorities.
Social barriers to listing for adult liver transplantation: Their prevalence and association with program characteristics
Authors: Flattau Anna , Olaywi Manhal , Gaglio Paul J. , Marcus Paula , Meissner Paul , Dorfman Emily B. L. , Reinus John F.
Published: June 2011

Social barriers to effective medical care are mandated to be routinely assessed as part of an evaluation for liver transplantation. This study explores how frequently liver transplant programs encounter these barriers in patients undergoing an evaluation and whether programs with higher proportions of Medicaid patients, historically disadvantaged minority patients, and rural patients encounter social barriers more frequently. A survey for assessing patient demographics and social barriers was electronically completed by representatives of 61 of 104 eligible US adult liver transplant programs (59%). Fifty-eight of the 61 programs identified themselves, and their characteristics were similar to those of all 104 US programs according to publicly available data from the Organ Procurement and Transplantation Network. Social barriers were reported to be encountered sometimes (10%-30%) or frequently (>30%) by the 61 programs as follows: inadequate or unstable health insurance (68.9% of the programs), a chaotic social environment (63.9%), a lack of a care partner (60.7%), an inability to obtain transportation (49.2%), a low educational level (36.1%), inadequate housing (23.0%), a language barrier (19.7%), no reliable way of contacting the patient (16.4%), difficulty in obtaining child care (11.5%), and food insecurity (8.2%). The frequencies of perceived social barriers did not differ significantly between programs reporting higher or lower proportions of Medicaid, minority, or rural patients. Our analysis suggests that program-level operational planning for addressing social barriers to transplant listing should be considered regardless of the proportions of Medicaid-insured, racial or ethnic minority, and rural patients in the population. Liver Transpl 17:1167–1175, 2011. © 2011 AASLD.
Patterned Hydrogel Substrates for Cell Culture with Electrohydrodynamic Jet Printing
Authors: Poellmann Michael J. , Barton Kira L. , Mishra Sandipan , Johnson Amy J. Wagoner
Published: June 2011

Cells respond to and are directed by physiochemical cues in their microenvironment, including geometry and substrate stiffness. The development of substrates for cell culture with precisely controlled physiochemical characteristics has the potential to advance the understanding of cell biology considerably. In this communication, E‐jet printing is introduced as a method for creating high‐resolution protein patterns on substrates with controlled elasticity. It is the first application of E‐jet printing on a soft surface. Protein spots as small as 5 µm in diameter on polyacrylamide are demonstrated. The patterned hydrogels are shown to support cell attachment and spreading. Polyacrylamide substrates patterned by E‐jet printing may be applied to further the study of cellular mechanobiology.

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A single‐nucleotide polymorphism in tumor suppressor gene SEL1L as a predictive and prognostic marker for pancreatic ductal adenocarcinoma in Caucasians
Authors: Liu Qian , Chen Jinyun , Mai Billy , Amos Christopher , Killary Ann M. , Sen Subrata , Wei Chongjuan , Frazier Marsha L.
Published: June 2011

SEL1L is a putative tumor suppressor gene that is frequently down‐regulated in pancreatic ductal adenocarcinoma (PDA). A single‐nucleotide polymorphism (SNP) rs12435998 in intron3 of SEL1L has previously been reported to be associated with susceptibility to Alzheimer's disease. We hypothesized that this SNP may influence clinical outcomes of patients with PDA. We analyzed DNA samples from 497 Caucasian patients with pathologically confirmed primary PDA. Of these, 98 had been enrolled in a clinical trial of neoadjuvant chemo‐radiotherapy and 77 of the 98 had subsequently undergone pancreaticoduodenectomy (PD). We performed Kaplan–Meier analysis to evaluate the correlation between different SNP genotypes and age at diagnosis, survival time after diagnosis, and survival time after PD. In nonsmokers, we found a significant difference in median age at diagnosis between variant genotypes (AG/GG) carriers and wild‐type genotype (AA) carriers (58 vs. 62 yr; log‐rank test, P = 0.017). Patients with variant genotypes also showed an increased hazard ratio (HR) of 1.45 [95% confidence interval (CI), 1.07–1.97] relative to wild‐type genotype. Among the patients in the clinical trial, the variant genotypes carriers had a median post‐PD survival time that was 34.7 months shorter than wild‐type genotype carriers (log‐rank test, P = 0.019; HR, 1.91; 95% CI, 1.09–3.34). Our results suggest that the rs12435998 SNP in SEL1L gene plays a role in modifying age at diagnosis of PDA in Caucasian nonsmokers. In addition, this SNP may serve as a prognostic marker in PDA patients who undergo the same or similar treatment as the clinical trials. © 2011 Wiley Periodicals, Inc.
Three‐dimensional phase contrast angiography of the mouse aortic arch using spiral MRI
Authors: Janiczek Robert L. , Blackman Brett R. , Roy R. Jack , Meyer Craig H. , Acton Scott T. , Epstein Frederick H.
Published: June 2011

Atherosclerosis is a complex disease whose spatial distribution is hypothesized to be influenced by the local hemodynamic environment. The use of transgenic mice provides a mechanism to study the relationship between hemodynamic forces, most notably wall shear stress (WSS), and the molecular factors that influence the disease process. Phase contrast MRI using rectilinear trajectories has been used to measure boundary conditions for use in computational fluid dynamic models. However, the unique flow environment of the mouse precludes use of standard imaging techniques in complex, curved flow regions such as the aortic arch. In this article, two‐dimensional and three‐dimensional spiral cine phase contrast sequences are presented that enable measurement of velocity profiles in curved regions of the mouse vasculature. WSS is calculated directly from the spatial velocity gradient, enabling WSS calculation with a minimal set of assumptions. In contrast to the outer radius of the aortic arch, the inner radius has a lower time‐averaged longitudinal WSS (7.06 ± 0.76 dyne/cm2 vs. 18.86 ± 1.27 dyne/cm2; P < 0.01) and higher oscillatory shear index (0.14 ± 0.01 vs. 0.08 ± 0.01; P < 0.01). This finding is in agreement with humans, where WSS is lower and more oscillatory along the inner radius, an atheroprone region, than the outer radius, an atheroprotective region. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Evaluation of MRI resolution affecting trabecular bone parameters: Determination of acceptable resolution
Authors: Kim Namkug , Lee June‐Goo , Song Youngkyu , Kim Hengjun J. , S. Yeom Jin , Cho Gyunggoo
Published: June 2011

The objective of this study is to evaluate the effect of MR image resolution on trabecular bone parameters and to determine the acceptable resolution that can be accurately analyzed to assess structural parameters. Ten distal femoral condyle specimens of 1 × 1 × 1 cm3 were scanned with a 4.7‐T Bruker BioSpec MRI scanner using a three‐dimensional fast large‐angle spin‐echo sequence with various iso‐cubic voxels sizes (65, 130, 160, 196, 230, and 260 μm). Otsu thresholding was applied to identify voxels containing bone. Conventional bone parameters, structural bone parameters, and skeleton‐based local trabecular thickness (slTB.Th) were evaluated. The Bland–Altman method and correlation indicated that the conventional and structural bone parameters were preserved with an iso‐cubic voxel size up to 230 μm (r > 0.932 and r > 0.843, respectively). In addition, slTB.Th derived from the highest resolution images (65 μm iso‐cubic voxel size), correlated well (r > 0.833) with the values computed from lower resolution images, up to 230 μm, which is twice typical human trabecular thickness range (100–150 μm). The outcome of this study suggests that the various bone parameters were well preserved up to 230 μm images. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Thalamus segmentation based on the local diffusion direction: A group study
Authors: Mang Sarah C. , Busza Ania , Reiterer Susanne , Grodd Wolfgang , Klose and Uwe
Published: June 2011

Fast and accurate segmentation of deep gray matter regions in the brain is important for clinical applications such as surgical planning for the placement of deep brain stimulation implants. Mapping anatomy from stereotactic atlases to patient data is problematic because of individual differences in subject anatomy that are not accounted for by commonly used atlases. We present a segmentation method for individual subject diffusion tensor MR data that is based on local diffusion information to identify subregions of the thalamus. We show the correspondence of our segmentation results to anatomy by comparison with stereotactic atlas data. Importantly, we verify the consistency of our segmentation by evaluating the method on 63 healthy volunteers. Our method is fast, reliable, and independent of any segmentation before the classification of regions within the thalamus. It should, therefore, be useful in clinical applications. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Evaluation of a vessel‐tracking‐based technique for dynamic targeting in human liver
Authors: Kokuryo Daisuke , Kumamoto Etsuko , Takao Yoshie , Fujii Susumu , Kaihara Toshiya , Kuroda Kagayaki
Published: June 2011

The purpose of this study was to evaluate a novel vessel‐tracking‐based technique for tracking of human liver. The novelty of the proposed technique is that it measures the translation and deformation of a local tissue region based on the displacements of a set of vessels of interest instead of the entire organ. The position of the target point was estimated from the relative positions of the center‐of‐masses of the vessels, assuming that the topological relationship between the target point and center‐of‐masses is unchanged during breathing. To reduce inaccuracy due to the delay between vessel image acquisition and sonication, the near‐future target position was predicted based on the vessel displacements in the images extracted from an image library acquired before the tracking stage. Experiments on healthy volunteers demonstrated that regardless of the respiratory condition, appropriate combinations of three center‐of‐masses from the vessels situated around the target‐tissue position yielded an estimation error of less than 2 mm, which was significantly smaller than that obtained when using a single center‐of‐mass trio. The effect of the tracking delay was successfully compensated, with a prediction error of less than 3 mm, by using over four images selected from the image library. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Bleomycin‐induced lung injury in mice investigated by MRI: Model assessment for target analysis
Authors: Babin Anna L. , Cannet Catherine , Gérard Christelle , Saint‐Mezard Pierre , Page Clive P. , Sparrer Helmut , Matsuguchi Tetsuya , Beckmann Nicolau
Published: June 2011

Magnetic resonance imaging (MRI) has been used to follow the course of bleomycin‐induced lung injury in mice and to investigate two knockout mouse lines with the aim of providing potential therapeutic targets. Bleomycin (0.25 mg/kg) was administered intranasally six times, once a day. MRI was carried out on spontaneously breathing animals up to day 70 after bleomycin. Neither cardiac nor respiratory gating was applied during image acquisition. A long lasting response following bleomycin has been detected by MRI in the lungs of male C57BL/6 mice. Histology showed that, from day 14–70 after bleomycin, fibrosis was the predominant component of the injury. Female C57BL/6 mice displayed a smaller response than males. Bleomycin‐induced injury was significantly more pronounced in C57BL/6 than in Balb/C mice. MRI and histology demonstrated a protection against bleomycin insult in female heterozygous and male homozygous cancer Osaka thyroid kinase knockout animals. In contrast, no protection was seen in cadherin‐11 knockout animals. In summary, MRI can quantify, in spontaneously breathing mice, bleomycin‐induced lung injury. With the ability for repetitive measurements in the same animal, the technique is attractive for in vivo target analysis and compound profiling in this murine model. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Arterial spin labeling angiography using a triple inversion recovery prepulse
Authors: Andia Marcelo E. , Botnar Rene M.
Published: June 2011

Arterial spin labeling is a well‐known noninvasive angiography technique, which does not necessitate the use of a contrast agent. arterial spin labeling is still clinically underused because of several challenges: (1) long scan times because of the need for two acquisitions (labeled and nonlabeled datasets), (2) sensitivity to spatial misregistration because of the need for image subtraction, and (3) the need for precise planning and choice of an optimal inversion delay for best blood‐to‐background contrast. In this work, we propose a new arterial spin labeling method based on a triple‐inversion‐recovery sequence‐arterial spin labeling. This approach exploits the ability of two nonselective inversion recovery prepulses to null the background signal over a wide range of T1 values, while maintaining the signal of labeled blood using a third slab selective inversion pulse. This technique therefore allows the acquisition of angiograms with a flexible inversion delay, easier planning procedure and no need for subtraction. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Seeing the smoking gun: a sensitive and specific method to visualize loss of the tumour suppressor, fumarate hydratase, in human tissues
Authors: Maxwell Patrick H.
Published: June 2011

In this issue of the Journal of Pathology, Bardella et al report a method for identifying tumours that lack fumarate hydratase. The approach they use is immunodetection of proteins that have been modified by a non‐enzymatic reaction of thiol groups in proteins with fumarate, which is termed succination. Validation included the use of mice with targeted inactivation of fumarate hydratase in the kidney, extensive studies of normal human tissues and examination of over 1000 specimens from human cancers not associated with FH mutations. Detection of protein succination is likely to provide a sensitive and specific method for pathologists to identify the small proportion of papillary renal cell carcinomas that are associated with germline mutations in the FH gene. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Influence of the use of functional foods enriched with phytosterols/‐stanols on adherence to statin therapy
Authors: Eussen Simone R. B. M. , Bouvy Marcel L. , Rompelberg Cathy J. M. , van der Elst Menno E. , Garssen Johan , Oosterveld Marco H. , de Boer Anthonius , de Gier Johan J. , van Kranen Henk J. , Klungel Olaf H.
Published: June 2011

Purpose

Subjects using functional foods with approved health claims may be more likely to be non‐adherent with prescribed drug therapy. This study aimed to assess the influence of the use of phytosterol/‐stanol‐enriched functional foods on adherence to statin therapy among patients initiating treatment.

Methods

We used data from the statin intervention research project, a randomized controlled trial aimed at improving adherence to statins. In the trial, new statin users were randomized to receive either usual care or extensive pharmaceutical care consisting of five individual counseling sessions. Customary use of phytosterol/‐stanol‐enriched products was identified by questionnaires filled out by all participants. Automated pharmacy‐dispensing records were used to assess adherence in terms of discontinuation of therapy and the medication possession ratio. Analyses were performed for the overall population, as well as stratified for receiving pharmaceutical or usual care.

Results

The use of functional foods enriched with phytosterols/‐stanols was not related to discontinuation of statin therapy, neither in the overall population (overall population adjusted hazard rate ratio (HRadj): 0.80 [95%CI: 0.59–1.08]), nor when stratified by randomization arm (pharmaceutical care HRadj: 0.77 [95%CI: 0.49–1.23]); usual care HRadj: 0.81 [95%CI: 0.54–1.21]). The median medication possession ratio was significantly lower in users of phytosterols/‐stanols in the usual care group, but the difference was not clinically relevant.

Conclusions

Customary use of phytosterol/‐stanol‐enriched functional foods did not affect adherence to statins in new users that are well informed on the beneficial effects of statin therapy. In daily medical practice, general practitioners and pharmacists should urge subjects not to take phytosterol/‐stanol‐enriched functional foods as replacement for their prescribed medication. Copyright © 2011 John Wiley & Sons, Ltd.
Proteomic methods unravel the protein quality control in Escherichia coli
Authors: Leichert Lars I.
Published: June 2011

Protein quality control is an essential process in all living organisms. A network of folding helper proteins and proteases ushers proteins into their native conformation, safeguards their structure under adverse environmental conditions, and, if all else fails, degrades proteins at the end of their life time. Escherichia coli is a versatile model organism used in the analysis of fundamental cellular processes. Much of what we know about protein quality control has been discovered in this microorganism. In the investigation of the mode of action, regulation and substrate specificity of chaperones, thiol‐disulfide isomerases and proteases, proteomic methods have been playing a key role. Here, we provide a condensed overview about the protein quality control network in E. coli and the remarkable contributions of proteomics to our current knowledge.
New anion conducting membranes based on functionalized styrene–butadiene–styrene triblock copolymer for fuel cells applications
Authors: Faraj Marco , Elia Elisabetta , Boccia Massimiliano , Filpi Antonio , Pucci Andrea , Ciardelli Francesco
Published: June 2011

In this work, the functionalization of polystyrene‐b‐poly(butadiene)‐b‐polystyrene triblock copolymer (SBS) with vinylbenzyl chloride and benzoyl peroxide (BPO) or α,α′‐azo‐bis‐isobutyronitrile (AIBN) as free radical initiators was reported. The functionalization degree (FD), calculated by 1H NMR spectroscopy and confirmed by elemental analysis, was highly tunable (from 4 to 10 mol %) and positively correlated to the starting percentage of radical initiator. More specifically, at the same initiator molar percentage grafting efficiency is higher using BPO rather than AIBN. Quaternization reaction of the grafted benzyl chloride groups with the bifunctional tertiary amine 1,4‐diazabicyclo[2.2.2]octane (Dabco) led to a chemically and thermally stable homogeneous anion‐exchange membrane. Electrochemical parameters were evaluated for Dabco‐quaternized grafted copolymers having different FDs, and compared with a commercial Tokuyama benchmark membrane. Experimental data showed a positive correlation between FD and both water swelling and ionic conductivity. Best trade‐off between ionic conductivity and water swelling was found for membrane having FD 9.1 mol %, which conductivity is comparable with the Tokuyama benchmark one and water uptake is only slightly higher. The results are discussed based on the molecular parameters with particular reference to ionic content and distribution. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Improved Hemocompatibility Guided by Pulsed Plasma Tailoring the Surface Amino Functionalities of TiO2 Coating for Covalent Immobilization of Heparin
Authors: Yang Zhilu , Wang Jin , Luo Rifang , Li Xin , Chen Si , Sun Hong , Huang Nan
Published: June 2011

This work aims to develop a facile and effective approach to tailoring amine functional groups on the TiO2 surface by depositing a thin film of plasma polymeric allylamine which is rich in amine groups. Furthermore, the primary amine groups on the surface are used to covalently immobilize heparin. The results reveal that heparin bound to the amine functionalized TiO2 surface not only shows a good retention, but also retains biological activity. The hemocompatibility evaluation shows less platelet adhesion, platelet activation and fibrinogen activation on the heparin immobilized TiO2 surface. Amine functionalized TiO2 surface remarkably promotes endothelial cell (EC) adhesion and proliferation. On the heparin immobilized TiO2 surface, although EC adhesion and proliferation is slightly suppressed at the beginning, after cultivation for 3 d, the growth behavior of ECs is obviously improved over pure TiO2 surface.

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Significant enhancement of breakdown voltage for GaN DHFETs by Si substrate removal
Authors: Srivastava Puneet , Das Jo , Visalli Domenica , Van Hove Marleen , Malinowski Pawel E. , Marcon Denis , Cheng Kai , Geens Karen , Leys Maarten , Decoutere Stefaan , Mertens Robert P. , Borghs Gustaaf
Published: June 2011

In this paper, we present a study on the substrate removal of AlGaN/GaN/AlGaN double‐heterostructure FETs (DHFETs) on Si (111) substrates by 2 different approaches: a global versus local removal route. We report on the significant enhancement of breakdown voltage (VBD) of DHFETs with only 2 µm thick AlGaN buffer in both cases. In the case of global Si removal, the Si substrate is completely removed and transferred to the sapphire carrier. However, for the local Si removal, the Si substrate is selectively etched only under the source‐to‐drain regions. Before Si removal, VBD saturates at ∼ 700 V at a gate‐drain distance (LGD) ≥ 8 µm: confirming electrical breakdown into the Si substrate. The breakdown voltage is remarkably enhanced after etching away the substrate by either of the techniques. We measure a VBD > 1100 V for devices with LGD ≥ 15 µm with a buffer thickness of only a 2 µm (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Properties of surface‐pit related emission in a ‐plane InGaN/GaN quantum wells grown on r ‐plane sapphire
Authors: Badcock T. J. , Hao R. , Moram M. A. , Dawson P. , Kappers M. J. , Humphreys C. J.
Published: June 2011

We have investigated the optical and structural properties of non‐polar (11‐20) In0.03Ga0.97N/GaN multiple quantum wells (MQWs) grown on r‐plane sapphire substrates. The emission spectrum is characterised by a peak at ∼370 nm and a blue‐green emission band (400–550 nm). The near‐UV peak at 370 nm is assigned to carrier recombination in the MQWs lying on the (11‐20) plane. On the basis of microscopy and cathodoluminescence imaging, the longer wavelength band is attributed to emission from sidewall MQWs formed on the various semi‐polar facets of structural defects which form during MQW growth at the lower temperatures and high NH3 flow in a nitrogen atmosphere. The spectral width of this band is proposed to originate from electronic disorder within individual sidewall QWs and variations between the structural properties of QWs formed on different semi‐polar facets (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Broadening of interband transitions in InGaN quantum wells
Authors: Gladysiewicz M. , Kudrawiec R. , Misiewicz J. , Siekacz M. , Cywinski G. , Skierbiszewski C.
Published: June 2011

Broadening of interband transitions was calculated for inhomogeneous InGaN quantum wells (QWs) dedicated for emitters operating in green spectral range. In order to simulate inhomogeneities for InGaN QW system, it was assumed that the QW width, barrier widths and indium concentration vary with a Gaussian distribution where the nominal QW width, barrier widths and indium concentration correspond to the mean value in this distribution and their fluctuations correspond to the deviation from the main value. Calculations of QW transitions were performed within the electron effective mass approximation for a thousand of randomly generated InGaN QWs and next a histogram of the intensity of optical transitions was built from the result of these calculations. In this way the influence of the each parameter (QW width, barrier width, and indium concentration) on the broadening of interband transitions was considered independently and, finally, all the parameters were taken into account at the same time. The obtained spectrum of interband transitions was compared with experimental data for InGaN QWs (i.e., photoluminescence and contactless electroreflectance measurements). It was found that the large broadening of interband transitions in InGaN QWs results from the inhomogeneous distribution of QW sizes and indium concentration. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical properties of GaN crystals grown by the ammonothermal technique
Authors: Wang Buguo , Weyburne David , Sun‐Paduano Qing , Swider Stacy , Suscavage Michael , Bliss David
Published: June 2011

High quality GaN crystals grown by the ammonothermal method are reported. The grown crystals possess excellent structural and optical properties. As confirmed by X‐ray diffractions, the crystals have very low overall Bragg peak broadening and particularly low twist variance. X‐ray rocking curves indicate the ammonothermal growth is replicating or improving from the seed crystal, with as low as 65 arc‐sec FWHM on (002) when using a 1×3 mm2 unslitted X‐ray spot size. Room temperature PL indicates the material has almost no yellow‐band emission although the yellow emission peak increased after annealing of the sample at 900 °C. The availability of yellow‐band free ammonothermal wafers offers a unique opportunity to study the origin of the yellow‐band emission in GaN (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurement of the Intrinsic Thermal Conductivity of a Multiwalled Carbon Nanotube and Its Contact Thermal Resistance with the Substrate
Authors: Yang Juekuan , Yang Yang , Waltermire Scott W. , Gutu Timothy , Zinn Alfred A. , Xu Terry T. , Chen Yunfei , Li Deyu
Published: June 2011

The intrinsic thermal conductivity of an individual carbon nanotube and its contact thermal resistance with the heat source/sink can be extracted simultaneously through multiple measurements with different lengths of the tube between the heat source and the heat sink. Experimental results on a 66‐nm‐diameter multiwalled carbon nanotube show that above 100 K, contact thermal resistance can contribute up to 50% of the total measured thermal resistance; therefore, the intrinsic thermal conductivity of the nanotube can be significantly higher than the effective thermal conductivity derived from a single measurement without eliminating the contact thermal resistance. At 300 K, the contact thermal resistance between the tube and the substrate for a unit area is 2.2 × 10−8 m2 K W−1, which is on the lower end among several published data. Results also indicate that for nanotubes of relatively high thermal conductance, electron‐beam‐induced gold deposition at the tube–substrate contacts may not reduce the contact thermal resistance to a negligible level. These results provide insights into the long‐lasting issue of the contact thermal resistance in nanotube/nanowire thermal conductity measurements and have important implications for further understanding thermal transport through carbon nanotubes and using carbon nanotube arrays as thermal interface materials.
Glycine receptor internalization by protein kinases activation
Authors: Velázquez‐Flores Miguel ángel , Salceda Rocío
Published: June 2011

Although glycine‐induced currents in the central nervous system have been proven to be modulated by protein kinases A (PKA) and C (PKC), the mechanism is not well understood. In order to better comprehend the mechanism involved in this phenomenon, we tested the PKA and PKC activation effect on the specific [3H]glycine and [3H]strychnine binding to postsynaptic glycine receptor (GlyR) in intact rat retina. The specific binding constituted about 20% of the total radioligand binding. Kinetic analysis of the specific binding exhibited a sigmoidal behavior with three glycine and two strychnine binding sites and affinities of 212 nM for [3H]glycine and 50 nM for [3H]strychnine. Specific radioligand binding was decreased (60–85%) by PKA and PKC activation, an effect that was blocked by specific kinases inhibitors, as well as by cytochalasin D. GlyR expressed in the plasma membrane decreased about 50% in response to kinases activation, which was consistent with an increase of the receptor in the microsomal fraction when PKA was activated. Moreover, immunoprecipitation studies indicated that these kinases lead to a time‐dependent receptor phosphorylation. Our results suggest that in retina, GlyR is cross‐regulated by G protein‐coupled receptors, activating PKA and PKC. Synapse 2011. © 2011 Wiley‐Liss, Inc.
Investigation of biochemical responses of Bacopa monnieri L. upon exposure to arsenate
Authors: Mishra Seema , Srivastava Sudhakar , Dwivedi Sanjay , Tripathi Rudra Deo
Published: June 2011

Widespread contamination of arsenic (As) is recognized as a global problem due to its well‐known accumulation by edible and medicinal plants and associated health risks for the humans. In this study, phytotoxicity imposed upon exposure to arsenate [As(V); 0–250 μM for 1–7 days] and ensuing biochemical responses were investigated in a medicinal herb Bacopa monnieri L. vis‐à‐vis As accumulation. Plants accumulated substantial amount of As (total 768 μg g−1 dw at 250 μM As(V) after 7 days) with the maximum As retention being in roots (60%) followed by stem (23%) and leaves (17%). The level of cysteine and total nonprotein thiols (NP‐SH) increased significantly at all exposure concentrations and durations. Besides, the level of metalloid binding ligands viz., glutathione (GSH) and phytochelatins (PCs) increased significantly at the studied concentrations [50 and 250 μM As(V)] in both roots and leaves. The activities of various enzymes viz., arsenate reductase (AR), glutathione reductase (GR), superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and catalase (CAT) showed differential but coordinated stimulation in leaves and roots to help plants combat As toxicity up to moderate exposure concentrations (50 μM). However, beyond 50 μM, biomass production was found to decrease along with photosynthetic pigments and total soluble proteins, whereas lipid peroxidation increased. In conclusion, As accumulation potential of Bacopa may warrant its use as a phytoremediator but if Bacopa growing in contaminated areas is consumed by humans, it may prove to be toxic for health. © 2011 Wiley Periodicals, Inc. Environ Toxicol 28: 419–430, 2013.
Adverse influence of coumestrol on secretory function of bovine luteal cells in the first trimester of pregnancy
Authors: Młynarczuk J. , Wróbel M. H. , Kotwica J.
Published: June 2011

Coumestrol is one of a few biologically active substances present in leguminous plants, which are widely used as fodder for ruminants. Depending on the doses, coumestrol acts on the reproductive processes as an estrogen‐like factor or antiestrogen to evoke a decrease in ovulation frequency, elongation of estrous cycle duration. The aim of the current investigations was to study the influence of coumestrol on secretory function of luteal cells obtained from first trimester of pregnant cows. Luteal cells (2.5 × 105/mL) from 3rd to 5th, 6th to 8th, and 9th to 12th week of pregnancy were preincubated for 24 h and incubated with coumestrol (1 × 10−6 M) for successive 48 h and the medium concentrations of progesterone (P4), oxytocin (OT), prostaglandin (PG) E2 and F2α were determined. Moreover, the expression of mRNA for neurophysin‐I/oxytocin (NP‐I/OT; precursor of OT) and peptidyl‐glycine‐α‐amidating mono‐oxygenase (PGA, an enzyme responsible for post‐translational OT synthesis) was determined after 8 h of treatment. Coumestrol did not affect P4 secretion but increased the secretion of OT from the cells collected at all stages of gestation studied. Hence, the ratio of P4 to OT was markedly decreased. Simultaneously, coumestrol increased the expression of NP‐I/OT mRNA during 9th to 12th weeks of pregnancy, and mRNA for PGA during 3rd to 5th and 9th to 12th weeks of gestation. Furthermore, coumestrol decreased PGE2 secretion from luteal cells in all studied stages of pregnancy, while it affected PGF2α metabolite (PGFM) concentration only from week 3 to 5 of pregnancy. Obtained results suggest that coumestrol impairs secretory function of the corpus luteum (CL) and this way it can affect the maintenance of pregnancy in the cow. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2013.
The Brazier effect in wind turbine blades and its influence on design
Authors: Jensen F.M. , Weaver P.M. , Cecchini L.S. , Stang H. , Nielsen R.F.
Published: June 2011

Critical failure was observed in the shear web of a wind turbine blade during a full‐scale testing. This failure occurred immediately before the ultimate failure and was partly caused by buckling and non‐linear cross‐sectional strain.

Experimental values had been used to compare and validate both numerical and semi‐analytical results in the analysis of the shear webs in the reinforced wind turbine blade. Only elastic material behaviour was analysed, and attention was primarily focused on the Brazier effect. The complex, geometrically non‐linear and elastic stress–strain behaviour of the shear webs and the cap in compression were analysed using a balance of experimental, numerical and analytical approaches. It was noted that the non‐linear distortion was caused by the crushing pressure derived from the Brazier effect. This Brazier pressure may have a significant impact on the design of new blades, and an optimized box girder had been studied to show the importance of including Brazier pressure in the design process for future wind turbine blades. Copyright © 2011 John Wiley & Sons, Ltd.
Cancer nanotechnology research in the United States and China: cooperation to promote innovation
Authors: Schneider Julie A. , Grodzinski Piotr , Liang Xing‐Jie
Published: June 2011

The application of nanotechnology to cancer research is a promising area for US–China cooperation. Cancer is a major public health burden in both countries, and progress in cancer nanotechnology research is increasing in several fields, including imaging, biomarker detection, and targeted drug delivery. The United States and China are international leaders in nanotechnology research, and have both launched national programs to support nanotechnology efforts in the recent past. The accelerating trend of co‐authorship among US and Chinese nanotechnology researchers demonstrates that individual scientists already recognize the potential for cooperation, providing a strong platform for creating additional partnerships in pre‐competitive research areas. Mechanisms that could help to enhance US–China cancer nanotechnology partnerships include: developing new programs for bi‐directional training and exchange; convening workshops focused on specific scientific topics of high priority to both countries; and joint support of collaborative research projects by US and Chinese funders. In addition to the accelerating scientific progress, expanded cooperation will stimulate important dialog on regulatory, policy, and technical issues needed to lay the groundwork for US and Chinese scientists to move greater numbers of cancer nanotechnology applications into the clinic. WIREs Nanomed Nanobiotechnol 2011 3 441–448 DOI: 10.1002/wnan.149

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease

Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine
Evidence for Tetrahedral Zinc in Amorphous In2–2xZnxSnxO3 (a‐ZITO)
Authors: Hoel Cathleen A. , Xie Sujing , Benmore Chris , Malliakas Christos D. , Gaillard Jean‐François , Poeppelmeier Kenneth R.
Published: June 2011

The structure of amorphous In2–2xZnxSnxO3 (a‐ZITO, x = 0.2, 0.3, 0.4) was investigated with transmission electron microscopy (TEM), the total scattering pair‐distribution function (PDF) and X‐ray absorption spectroscopy (XAS), which revealed a well‐defined short‐range structure that differed from the crystalline bixbyite and corundum ZITO polymorphs. The X‐ray absorption near edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) were used to detect InO6 and SnO6 octahedra and ZnO4 tetrahedra in a‐ZITO, which differ from the InO6, SnO6 and ZnO6 pseudo‐octahedra that are observed in the bixbyite and corundum ZITO polymorphs. The formation of the ZnO4 tetrahedron likely inhibits the crystallization of ZITO when synthesized under mild conditions. in situ XRD showed a gradual transition from a‐ZITO to a mixture of the bixbyite and corundum ZITO polymorphs as the temperature was raised from 300 °C to 568 °C.
Endoscopic double‐metallic stenting for malignant biliary and duodenal obstructions
Authors: Moon Jong Ho , Choi Hyun Jong
Published: June 2011

Background

Endoscopic metallic stenting is a safe, effective treatment for malignant biliary obstructions, but can be technically difficult when combined malignant biliary and duodenal obstructions exist. Available duodenal metallic stents feature a tight mesh unsuitable for transpapillary biliary stenting. We evaluated the feasibility and usefulness of new endoscopic procedures for endoscopic double‐stent placement in managing such obstructions.

Methods

The through‐the‐scope duodenal metallic stent has a central cross‐wired, unfixed structure that allows insertion of the biliary stent through the mesh wall of a duodenal stent. Transpapillary endoscopic placement of a biliary stent was performed through the lumen of this duodenal stent. Endoscopic ultrasound (EUS)‐guided biliary drainage was performed successfully through the duodenal bulb after puncturing with a 19G needle. Biliary metallic stenting through the choledochoduodenal tract and effective drainage were achieved.

Conclusions

Use of a combined endoscopic biliary and duodenal stent inserted through the mesh of the new duodenal metallic stent is feasible and effective in managing the aforementioned obstructions. EUS‐guided biliary metal stenting is a therapeutic option for endoscopic management when a failed transpapillary approach through the lumen of the duodenal stent occurs. The continued development of endoscopic procedures and devices should resolve issues associated with complicated strictures.
Antioxidant micronutrient supplementation increases erythrocyte membrane fluidity in adults from a rural Chinese community
Authors: Han Xiu-Xia , Zhang Ming , Ma Ai-Guo , Ge Sheng , Shi Xue-Xiang , Sun Yong-Ye , Wang Qiu-Zhen , Liang Hui
Published: June 2011

The objective of the present study was to investigate age-related differences in erythrocyte membrane fluidity (EMF) and changes in antioxidant capacity following supplementation. A total of seventy-four children were randomly divided into two groups: group A1 was the placebo-controlled group and group A2 was supplemented daily with 600 μg retinol, 1·0 mg β-carotene, 100 mg tocopherol, 300 mg ascorbic acid and 200 μg Se. A total of ninety young people were randomly divided into B1 and B2 groups, and ninety-one elderly subjects were divided into C1 and C2 groups. Groups B1 and C1 were placebo-controlled groups, and groups B2 and C2 were daily supplemented with 900 μg retinol, 1·5 mg β-carotene, 200 mg tocopherol, 500 mg ascorbic acid and 400 μg Se. Results showed that plasma malondialdehyde (MDA) was 5·35 μmol/l in children, which was lower than in young and elderly people. The MDA levels of the young and elderly individuals in the treated groups were significantly lower compared with the control groups, but the supplementation did not alter MDA levels in children. At baseline, there was a lower value of polarisation (ρ) and microviscosity (η) in children, indicating a higher EMF, than in both the young and elderly subjects. After the 2-month trial, the ρ and η values of young and elderly subjects in the treated groups decreased significantly in comparison with the placebo groups, indicating an increase in EMF. In conclusion, there was a background of higher MDA levels and lower EMF in young and elderly people than in children, which could be improved by antioxidant supplementation.
Health effects of green tea catechins in overweight and obese men: a randomised controlled cross-over trial
Authors: Brown A. L. , Lane J. , Holyoak C. , Nicol B. , Mayes A. E. , Dadd T.
Published: June 2011

Regular consumption of green tea may be cardioprotective. In the present study we investigated the health effects of dietary supplementation with green tea catechins and the potential modifying effect of the catechol-O-methyltransferase (COMT) Val/Met genotype. Subjects (sedentary males, aged 40–69 years, with BMI ≥  28 and ≤  38 kg/m2) were randomly assigned to consume decaffeinated green tea extract (DGT; 530 mg containing about 400 mg total catechins/capsule, twice daily) and placebo in a complete cross-over design. Ambulatory blood pressure and biomarkers of metabolic function (cholesterol, TAG, glucose and insulin) were measured at weeks 0 and 6. Although a marked increase in the concentration of plasma epigallocatechin gallate (EGCG), urinary epigallocatechin (EGC) and urinary 4′-O-methyl EGC was found after DGT treatment, no effect on blood pressure or biomarkers of metabolic function was observed. However, a period × treatment interaction (P < 0·05) was detected for body-weight change. Despite a similar increase in estimated energy intake during intervention period 1, body weight decreased by 0·64 (sd2·2) kg and increased by 0·53 (sd1·9) kg in the DGT and placebo groups, respectively (P = 0·025), suggesting a protective effect of green tea catechins on weight gain. Additionally, the COMT Val/Met genotype influenced urinary accumulation of EGC and 4′-O-methyl EGC (P < 0·01). Mean concentrations were lower in individuals homozygous for the high-activity G-allele, possibly reflecting increased metabolic flux and a more rapid conversion to downstream metabolic species, compared with individuals carrying at least one copy of the low-activity A-allele. Additional studies are needed to confirm these findings and further explore the modifying effect of genotype.
A Theory of Merger-Driven IPOs
Authors: Hsieh Jim , Lyandres Evgeny , Zhdanov Alexei
Published: June 2011

We propose a model that links a firm’s decision to go public with its subsequent takeover strategy. A private bidder does not know a firm’s true valuation, which affects its gain from a potential takeover. Consequently, a private bidder pursues a suboptimal restructuring policy. An alternative route is to complete an initial public offering (IPO) first. An IPO reduces valuation uncertainty, leading to a more efficient acquisition strategy, therefore enhancing firm value. We calibrate the model using data on IPOs and mergers and acquisitions (M&As). The resulting comparative statics generate several novel qualitative and quantitative predictions, which complement the predictions of other theories linking IPOs and M&As. For example, the time it takes a newly public firm to attempt an acquisition of another firm is expected to increase in the degree of valuation uncertainty prior to the firm’s IPO and in the cost of going public, and it is expected to decrease in the valuation surprise realized at the time of the IPO. We find strong empirical support for the model’s predictions.