bluuebunny/crossref_metadata_2025 huggingface dataset:
Role for toll‐like receptor 3 in muscle regeneration after cardiotoxin injury
Authors: Mathes Allison L. , Lafyatis Robert
Published: April 2011

Introduction: Sterile tissue injury induces an inflammatory response involving cytokines that have crucial roles in the tissue repair that follows. Methods: MyH3 and type 1 interferon (IFN) were assessed by qPCR after cardiotoxin (CTX)‐induced muscle injury. Results: CTX‐induced injury increased expression of IFN‐regulated genes, IFIT1 and MX‐2, which was blocked in type 1 IFN receptor (IFNR)‐deficient mice. However, IFNR‐deficient mice showed no significant differences in muscle regeneration as assessed by MyH3 expression. MyH3 was significantly reduced in TLR3‐deficient but not MyD88‐deficient mice. TLR3‐deficient mice also showed altered expression of proinflammatory cytokines, IL‐6, IL‐1β, and TNF‐α. Conclusions: CTX‐induced muscle injury increased markers of innate immune activation, but blocking type 1 IFN signaling had no effect on muscle regeneration. Taken together, these results suggest a role for TLR3, and perhaps other innate immune signals, in the inflammatory response to CTX‐induced muscle injury and consequent muscle regeneration. Muscle Nerve, 2011
Mechanomyographic responses are not influenced by the innervation zone for the vastus medialis
Authors: Malek Moh H. , Coburn Jared W.
Published: March 2011

Introduction: The purposes of this study were to: (1) compare the power output–related patterns of absolute and normalized mechanomyographic (MMG) amplitude and mean power frequency (MPF) signals across the innervation zone (IZ) during incremental cycle ergometry; and (2) examine the influence of the IZ on the mean MMG amplitude and MPF values. Methods: Ten men performed incremental cycle ergometry tests to exhaustion. Surface MMG signals were recorded simultaneously from accelerometer arrangements placed on the vastus medialis over the IZ and proximal and distal to the IZ. Results: The results of polynomial regression indicate that the best‐fit model for each site was consistent for each subject for MMG amplitude, but not for MMG MPF. Two‐way analyses of variance (ANOVAs) revealed no site × power output interaction (P > 0.05) for absolute and normalized MMG amplitude and MPF values. Conclusion: Our findings demonstrate that the IZ does not influence the MMG signal during dynamic exercise. Muscle Nerve 44: 424–431, 2011
Using complementary DNA from MyoD‐transduced fibroblasts to sequence large muscle genes
Authors: Waddell Leigh B. , Monnier Nicole , Cooper Sandra T. , North Kathryn N. , Clarke Nigel F.
Published: March 2011

Large muscle genes are often sequenced using complementary DNA (cDNA) made from muscle messenger RNA (mRNA) to reduce the cost and workload associated with sequencing from genomic DNA. Two potential barriers are the availability of a frozen muscle biopsy, and difficulties in detecting nonsense mutations due to nonsense‐mediated mRNA decay (NMD). We present patient examples showing that use of MyoD‐transduced fibroblasts as a source of muscle‐specific mRNA overcomes these potential difficulties in sequencing large muscle–related genes. Muscle Nerve, 2011
Once‐daily trospium chloride 60 mg extended‐release provides effective, long‐term relief of overactive bladder syndrome symptoms
Authors: Zinner Norman R. , Dmochowski Roger R. , Staskin David R. , Siami Paul F. , Sand Peter K. , Oefelein Michael G.
Published: April 2011

Aims

Once‐daily extended‐release (XR) trospium chloride has been evaluated for the treatment of overactive bladder syndrome (OAB) in two 12‐week randomized, double‐blind, placebo‐controlled studies. This pooled analysis of the 9‐month open‐label extensions to these studies evaluated the long‐term efficacy and tolerability of trospium XR.

Methods

Following double‐blind treatment, subjects with OAB could enter the open‐label period, during which they received trospium 60 mg XR once daily for 36 weeks. The primary efficacy variables were changes from baseline in the number of toilet voids and urgency urinary incontinence (UUI) episodes per day at Week 48. Adverse events (AEs) were also recorded.

Results

Of the 1,027 subjects who completed double‐blind treatment, 944 (92%) continued into the open‐label period (placebo‐to‐trospium, N = 483; trospium‐to‐trospium, N = 461); 332 (68.7%) and 335 (72.7%), respectively, completed the open‐label period. At Week 48, the mean change from baseline in the number of toilet voids/day was −3.21 in the placebo‐to‐trospium group and −3.35 in the trospium‐to‐trospium group, and the median change from baseline in the number of UUI episodes/day was −2.33 in both groups. Efficacy was maintained relative to Week 12 in trospium‐to‐trospium subjects, while improvement was seen following trospium initiation in placebo‐to‐trospium subjects. Improvement from baseline was also observed on secondary efficacy parameters at Week 48. Trospium was well tolerated; dry mouth and constipation were the most common class treatment‐emergent AEs. Central nervous system AEs were rare and did not increase with long‐term treatment.

Conclusions

Long‐term treatment of OAB with once‐daily trospium 60 mg XR is effective and well tolerated. Neurourol. Urodynam. 30:1214–1219, 2011. © 2011 Wiley‐Liss, Inc.
Application of flow cytometry in pediatric hematology‐oncology
Authors: Varma Neelam , Naseem Shano
Published: April 2011

Applications of flow cytometry in pediatric cancers have expanded substantially in recent years. In acute leukemias, the commonest childhood cancer, flow cytometry can now define complex antigenic profiles that are associated with specific cytogenetic/molecular defects and can also directly identify BCR‐ABL fusion protein. Flow cytometry based scoring system has been described for diagnosis of myelodysplastic syndromes. In solid tumors, flow cytometry was previously used mainly to determine DNA content for prognosis; however, recent studies in children with neuroblastoma and Ewing sarcoma have identified its diagnostic utility. In this review, we will discuss the current and future applications of flow cytometry in pediatric hematology‐oncology. Pediatr Blood Cancer 2011;57:18–29. © 2011 Wiley‐Liss, Inc.
Cystatin C more accurately detects mildly impaired renal function than creatinine in children receiving treatment for malignancy
Authors: Blufpand Hester N. , Tromp Jorien , Abbink Floor C.H. , Stoffel‐Wagner Birgit , Bouman Anneke A. , Schouten‐van Meeteren Antoinette Y.N. , van Wijk Joanna A.E. , Kaspers Gertjan J.L. , Bökenkamp Arend
Published: April 2011

Background

Monitoring of renal function is crucial in pediatric oncology. The use of creatinine to estimate glomerular filtration rate (GFR) is hampered by its dependency on muscle mass. Muscle wasting is common in children with cancer, leading to overestimation of GFR. Data on cystatin C are sparse in pediatric oncology, although this marker could be particularly useful in this population.

Procedure

Inulin clearance, estimated GFR using serum cystatin C according to Filler (eGFRcys) and serum creatinine according to Schwartz (eGFRcrea) were measured in 68 children with malignancy and 121 controls. We analyzed the difference between measured and estimated GFR and performance, bias and accuracy.

Results

Multiple linear regression analysis showed overestimation of GFR by eGFRcrea in females (B = −21.18; P = 0.001), and in patients with malignancy (B = −21.77; P = 0.014). eGFRcys overestimated GFR in females (B = −10.47; P = 0.001), but was independent of treatment for malignancy. Agreement with gold standard in detecting GFR below 90 ml/min/1.73 m2 is better for eGFRcys (AUC 0.854) than for eGFRcrea (AUC 0.675) in the group with cancer. They performed comparably in the control group. Bland–Altman analysis showed considerable bias for eGFRcrea compared to eGFRcys (−14.3 ml/min/1.73 m2 vs. −7.3 ml/min/1.73 m2). The proportion of estimates within 30% of true GFR for eGFRcrea (72.1%) was lower than for eGFRcys (82.4%) in the group with cancer. In the control group eGFRcrea (84.3%) outperformed eGFRcys (76.0%). When using the 50% limits of agreement, eGFRcys outperformed eGFRcrea in both groups.

Conclusion

Cystatin C more accurately detects mildly impaired renal function than creatinine in children receiving treatment for malignancy. Pediatr Blood Cancer 2011; 57: 262–267. © 2011 Wiley‐Liss, Inc.
Durability test of PVP‐capped Pt nanoclusters counter electrode for highly efficiency dye‐sensitized solar cell
Authors: Lan Jo‐Lin , Wan Chi‐Chao , Wei Tzu‐Chien , Hsu Wen‐Chi , Chang Ya‐Huei
Published: March 2011

In this paper, the durability of PVP‐capped Pt nanoclusters counter electrode (PVP‐Pt CE) for dye‐sensitized solar cell (DSSC) has been extensively evaluated including electrochemical reaction durability, thermal stress durability and light soaking durability. It is revealed that PVP‐Pt CE exhibits both electrochemical and thermal durability by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) test. Moreover, DSSC containing PVP‐Pt CE shows over 9.37% conversion efficiency in highly volatile electrolyte system. As to device thermal durability, both low‐volatile and non‐volatile electrolyte systems were tested and the results show relative efficiency can maintain more than 85% after accelerated thermal test at 85°C for 1000 h, and 110% after 60°C for 1000 h. Finally, after continuous light soaking test under 60°C for 1000 h, the relative efficiency can still maintain at 94%. Copyright © 2011 John Wiley & Sons, Ltd.
Biomarker discovery from the top down: Protein biomarkers for efficient virus transmission by insects (Homoptera: Aphididae) discovered by coupling genetics and 2‐D DIGE
Authors: Cilia Michelle , Howe Kevin , Fish Tara , Smith Dawn , Mahoney Jaclyn , Tamborindeguy Cecilia , Burd John , Thannhauser Theodore W. , Gray Stewart
Published: April 2011

Yellow dwarf viruses cause the most economically important virus diseases of cereal crops worldwide and are vectored by aphids. The identification of vector proteins mediating virus transmission is critical to develop sustainable virus management practices and to understand viral strategies for circulative movement in all insect vectors. Previously, we applied 2‐D DIGE to an aphid filial generation 2 population to identify proteins correlated with the transmission phenotype that were stably inherited and expressed in the absence of the virus. In the present study, we examined the expression of the DIGE candidates in previously unstudied, field‐collected aphid populations. We hypothesized that the expression of proteins involved in virus transmission could be clinically validated in unrelated, virus transmission‐competent, field‐collected aphid populations. All putative biomarkers were expressed in the field‐collected biotypes, and the expression of nine of these aligned with the virus transmission‐competent phenotype. The strong conservation of the expression of the biomarkers in multiple field‐collected populations facilitates new and testable hypotheses concerning the genetics and biochemistry of virus transmission. Integration of these biomarkers into current aphid‐scouting methodologies will enable rational strategies for vector control aimed at judicious use and development of precision pest control methods that reduce plant virus infection.
Citrulline‐modified phage display: A novel high‐throughput discovery approach for the identification of citrulline‐containing ligands
Authors: Somers Klaartje , Stinissen Piet , Somers Veerle
Published: March 2011

Phage display is a high‐throughput technology used to identify ligands for a given target. A drawback of the approach is the absence of PTMs in phage‐displayed peptides. The applicability of phage display could be broadened considerably by the implementation of PTMs in this system. The aim of this study was to investigate the possible application of citrullination, a PTM of an arginine into a citrulline amino acid, in filamentous (M13) and lytic (T7) phage display. After in vitro citrullination of T7 and M13 phages, citrullination was confirmed and the infectivity of both citrullinated and non‐citrullinated phage was compared by titer determination. We demonstrated the successful in vitro citrullination of T7 and M13 phage‐displayed peptides. This in vitro modification did not affect the viability or infectivity of the T7 virions, a necessary prerequisite for the implementation of this approach in T7 phage display. For M13 phage, however, the infecting phage titer decreased five‐fold upon citrullination, limiting the use of this modification in M13 phage display. In conclusion, in vitro citrullination can be applied in T7 phage display giving rise to a high‐throughput and sensitive approach to identify citrulline‐containing ligands by the use of the strengths of phage display technology.
Role of balanced charge carrier transport in low band gap polymer:Fullerene bulk heterojunction solar cells
Authors: Kotlarski Jan D. , Moet Date J. D. , Blom Paul W. M.
Published: April 2011

Lowering of the optical band gap of conjugated polymers in bulk heterojunction solar cells not only leads to an increased absorption but also to an increase of the optimal active layer thickness due to interference effects at longer wavelengths. The increased carrier densities due to the enhanced absorption and thicker active layers make low band gap solar cells more sensitive to formation of space charges and recombination. By systematically red shifting the optical parameters of poly[2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐p‐phenylenevinylene] and 6,6‐phenyl C61‐butyric acid methyl ester, we simulate the effect of a reduced band gap on the solar cell efficiencies. We show that especially the fill factor of low band gap cells is very sensitive to the balance of the charge transport. For a low band gap cell with an active layer thickness of 250 nm, the fill factor of 50% for balanced transport is reduced to less than 40% by an imbalance of only one order of magnitude. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Successful strategies for implementing biopsychosocial screening
Authors: Loscalzo Matthew , Clark Karen Lynn , Holland Jimmie
Published: April 2011

Objective: This commentary integrates successful screening implementation strategies applied in four institutions in the United States and the accumulated knowledge from international leaders about how to engage key professionals and administration in partnering to create a culture of screening.

Methods: As in clinical practice, it is first necessary to know the patient's story, potential resources and what motivates them to coordinated meaningful action. Introducing a comprehensive program of screening shares similarities with clinical care but also requires additional insights and an understanding of what motivates institutions to make resources available. Specific behaviors that are tailored to the values of particular professions and the institution are described to increase the likelihood of program uptake. Once key professionals and administration understand the value of screening and not before, a screening implementation plan is put into place.

Results: Since the 1990s our screening programs have been successfully implemented in four settings: three NCI Designated Comprehensive Cancer Centers and one community hospital. It is estimated that more than 15,000 cancer outpatients have been screened for distress and cancer‐related problems. These programs have demonstrated that biopsychosocial screening programs can be integrated into busy outpatient cancer clinics as part of standard clinical care.

Conclusions: Screening involves an intervention that impacts patients, clinical systems, the institution and staffing levels of psychosocial providers. Provision of scarce resources, active engagement of key professionals and administration will only occur if the stakeholders have a clear sense of the benefits for them. Implementing a screening program creates culture change and culture change not only takes time, but active engagement, patience and persistence. Copyright © 2011 John Wiley & Sons, Ltd.
Implementing screening for distress, the 6th vital sign: a Canadian strategy for changing practice
Authors: Bultz Barry D. , Groff Shannon L. , Fitch Margaret , Blais Marie Claude , Howes Janice , Levy Karen , Mayer Carole
Published: April 2011

Objective: Distress is prevalent among cancer patients at all stages of illness and has been endorsed as the 6th Vital Sign in cancer care. Despite its prevalence, and calls to be monitored, few cancer programs are Screening for Distress in a standardized manner. In this paper, the implementation strategy employed in Canada to change practice by integrating Screening for Distress in routine care is described.

Methods: The process from inception of the concept of distress to the implementation of Screening for Distress is discussed. Pioneering work pertinent in laying the foundation for Screening for Distress as a National initiative is highlighted. Additionally, the experience of four jurisdictions currently Screening for Distress is utilized to demonstrate steps to successful implementation and strategies for overcoming challenges.

Results: Integrating Screening for Distress into practice requires endorsements from key stakeholders, developing and disseminating national recommendations and guidelines, and utilizing a coordinated and standardized method focused on practice change. At a local level successful implementations engage stakeholders, provide thorough and targeted education, establish interprofesionnal teams, and utilize a phased approach to implementation. Common challenges cited include time, buy‐in and lack of resources.

Conclusions: Establishing a national approach to implementing Screening for Distress is both feasible and beneficial. A coordinated approach encourages collaboration beyond the walls of any particular center and provides the opportunity for all patients to be provided with improved person‐centered care. Copyright © 2011 John Wiley & Sons, Ltd.
Validation of a web‐based version of the asthma control test and childhood asthma control test
Authors: Koolen B.B. , Pijnenburg M.W.H. , Brackel H.J.L. , Landstra A.M. , van den Berg N.J. , Merkus P.J.F.M. , Hop W.C.J. , Vaessen‐Verberne A.A.P.H.
Published: April 2011

Rationale

Recent guidelines focus on adjusting asthma treatment to the level of asthma control. The availability of a web‐based asthma control questionnaire offers the possibility to assess asthma control without the need of outpatient clinic visits.

The aim of this study was to evaluate the agreement between web‐based and paper‐based versions of the Asthma Control Test (ACT) and Childhood Asthma Control Test (C‐ACT), short‐term reproducibility and satisfaction with both versions.

Methods

One hundred seventy‐three children with stable asthma and a normal lung function were randomized to fill in a web‐based or paper‐based version of the C‐ACT (4–11 years) or ACT (12–18 years). According to a cross‐over design, they completed the opposite version after 1 week. Reproducibility was evaluated by repeating the 2nd version (web‐ or paper‐based) 7 days later.

Results

Eighty‐eight children filled in the C‐ACT, 68 children filled in the ACT. Intraclass Correlation Coefficient (ICC) for web‐based versus paper‐based C‐ACT was 0.81 (95% confidence interval [95% CI] 0.72–0.87). For ACT this was 0.84 (95% CI 0.76–0.90). For web‐based and paper‐based C‐ACT the reproducibility ICC was 0.82 (95% CI 0.67–0.90) and 0.75 (95% CI 0.59–0.85), respectively. The reproducibility ICC of the ACT for web‐ and paper‐based versions was 0.93 (95% CI 0.87–0.97) and 0.77 (95% CI 0.59–0.88), respectively. Eighty‐six percent of patients preferred the web‐based version.

Conclusion

The web‐based version of the C‐ACT and ACT is reproducible and comparable with the paper‐based version in assessing asthma control. Most children and their parents prefer the web‐based version. Pediatr. Pulmonol. 2011; 46:941–948. © 2011 Wiley‐Liss, Inc.
Discovery and initial validation of α 1‐B glycoprotein fragmentation as a differential urinary biomarker in pediatric steroid‐resistant nephrotic syndrome
Authors: Piyaphanee Nuntawan , Ma Qing , Kremen Oran , Czech Kimberly , Greis Kenneth , Mitsnefes Mark , Devarajan Prasad , Bennett Michael R.
Published: March 2011

Purpose: In this cross‐sectional pilot study we set out to discover a non‐invasive biomarker that could distinguish steroid‐resistant nephrotic syndrome (SRNS) from steroid‐sensitive nephrotic syndrome (SSNS).

Experimental design: Urine and clinical data were collected from patients with idiopathic nephrotic syndrome and healthy controls. Using SELDI‐TOF‐MS, we identified an 11‐fold upregulated 13.8 kDa fragment of α 1‐B glycoprotein (A1BG) in urine in SRNS. To validate our findings, A1BG was detected by Western blot. Creatinine was measured and transformed to glomerular filtration rate (GFR) by the new Schwartz formula and classified to chronic kidney disease (CKD) stage. p‐Values were determined by unpaired t‐test and Mann–Whitney rank sum test. Microalbumin was also measured to determine albumin/creatinine ratios.

Results: The 13.8 kDa A1BG was present in 7 of 19 patients with SRNS; but absent in all SSNS (n=15) and controls (n=10). The A1BG+ patients had lower GFR than A1BG− patients (p<0.009) and tended to have higher CKD stage.

Conclusion and clinical relevance: The 13.8 kDa A1BG fragment had a high discriminatory power for steroid resistance in pediatric nephrotic syndrome, but is only present in a subset of patients. Additional longitudinal studies are required to determine the usefulness of this biomarker as a non‐invasive predictive marker of therapeutic response.
Glucose interactions with a model peptide
Authors: Mason Phillip E. , Lerbret Adrien , Saboungi Marie‐Louise , Neilson George W. , Dempsey Christopher E. , Brady John W.
Published: April 2011

Molecular dynamics simulations have been conducted of the helical polypeptide melittin, in concentrated aqueous solutions of the alpha and beta anomers of D‐glucopyranose. Glucose is an osmolyte, and it is expected to be preferentially excluded from the surfaces of proteins. This was indeed found to be the case in the simulations. The results indicate that the observed exclusion may have a contribution from an under‐representation of hydrogen bonding interactions between glucose groups and exposed side chains, compared to water. However, glucose was found to bind quite specifically to melittin by stacking its hydrophobic face, consisting of aliphatic protons, against the flat hydrophobic face of the indole group of the tryptophan‐19 side chain. Although the binding site for this interaction is localized, the binding is weak for both anomers, with a binding free energy estimated as only ∼0.5 kcal/mol (i.e. near kBT). The face of the sugar stacked against the Trp indole ring is different for the two anomers of glucose, due to the disruption of the H1‐H3‐H5 hydrophobic triad of the beta anomer by the axial C1 hydroxyl group in the alpha anomer. The measurable affinity of the sugar for the Trp side chain is consistent with the very frequent occurrence of this group in the binding sites of proteins that complex with sugars. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Magnetic properties of ultrafine‐grained cobalt samples obtained from consolidated nanopowders
Authors: Fellah F. , Chérif S. M. , Bouziane K. , Schoenstein F. , Jouini N. , Dirras G.
Published: March 2011

Co powders having nominal average particle size of 50 and 240 nm were synthesized using a polyol method and then consolidated by hot isostatic pressing (HIP) or the emerging spark plasma sintering (SPS) compaction processes. Bulk polycrystalline aggregates were obtained, having average grain sizes of about 200 and 300 nm, respectively. It is found that both nanoparticles and consolidated samples exhibit a soft ferromagnetic behavior. The magnetization reversal likely occurs by nucleation/propagation process. However, a curling process can be involved in the magnetization reversal for the smaller particles. The dynamic measurements provide for the consolidated samples magnetic parameters corresponding to bulk cobalt with vanishing anisotropy. The contribution of the intergranular region is found to be negligible. We can infer that the used consolidation routes insure a good magnetic interfacial contact between the particles.
Nanostructuring in β‐Zn4Sb3 with variable starting Zn compositions
Authors: Rauwel Protima , Løvvik Ole Martin , Rauwel Erwan , Toberer Eric S. , Snyder G. Jeffrey , Taftø Johan
Published: March 2011

Thermoelectric Zn4−δSb3 samples with varying Zn concentrations were synthesized. The morphology, along with planar and extended defects was studied using transmission electron microscopy (TEM). For all the Zn concentrations, nanostructuring was observed. Depending on the Zn concentration, two different types of nanostructures were observed: nanovoids and nanograins. Three samples with Zn:Sb ratios of 1.28, 1.30, and 1.36 were studied. The presence of the secondary phases was discussed in terms of the phase diagram. Density functional theory (DFT) calculations further elucidated the formation of secondary phases as a function of different Zn:Sb ratio.

magnified image

ZnSb nanoparticles in β‐Zn4Sb3.
Electronic and magnetic structure of carbides RRh3C
Authors: Djermouni Mostefa , Kacimi Salima , Zaoui Ali
Published: March 2011

Ab initio calculations are performed to study the electronic and magnetic properties of the cubic inverse perovskite RRh3C (R = rare earth) compounds. In this work, we used the accurate augmented plane‐wave plus local orbital method to find the equilibrium structural parameters and to determine the magnetic stability of each material. We investigated the electronic structure with the spin‐orbit interaction and on‐site Coulomb potential for the R‐derived 4f orbitals to obtain the correct ground state of RRh3C. The exchange interaction between local f electrons and conduction electrons play an important role in the heavy fermions characters. The fully relativistic band structure scheme shows that spin‐orbit coupling splits the 4f states into many manifolds. We confirm the results of recently synthesized cubic phases [Phys. Rev. B 80, 224404 (2009)].
Optical and theoretical investigations of V2+ ion in GaN
Authors: Souissi Hajer , Souissi Mnawer , Dammak Mohamed , Chine Zied , Kammoun Souha , El Jani Belgacem
Published: March 2011

The infrared luminescence of vanadium‐doped gallium nitride (GaN:V) grown by metalorganic vapour phase epitaxy technique (MOVPE) on SiN‐treated sapphire substrate were examined. Two spin allowed transitions were observed at 6633 cm‐1 and 6959 cm‐1, and are respectively assigned to the 4T1(4P)→4T1(4F) and 4A2(4F) → 4T1(4F) transition of V2+ (3d3) in a tetrahedral symmetry with a 4T1 ground state. Crystal‐field calculation of the detected transition energies based on the Tanabe‐Sugano scheme is presented. Good agreements between theoretical and experimental energy levels are obtained. The presence of a series of vibronic state is also discussed in this work (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of the in‐plane effective mass and quantum lifetime of 2D electrons in AlGaN/GaN based HEMTs
Authors: Celik Ozlem , Tiras Engin , Ardali Sukru , Lisesivdin Sefer Bora , Ozbay Ekmel
Published: March 2011

Magnetoresistance and Hall resistance measurements have been used to investigate the electronic transport properties of AlGaN/GaN based HEMTs. The Shubnikov–de Haas (SdH) oscillations from magnetoresistance, is obtained by fitting the nonoscillatory component to a polynomial of second degree, and then subtracting it from the raw experimental data. It is shown that only first subband is occupied with electrons. The two‐dimensional (2D) carrier density and the Fermi energy with respect to subband energy (EF–E1) have been determined from the periods of the SdH oscillations. The in‐plane effective mass (m*) and the quantum lifetime (τq) of electrons have been obtained from the temperature and magnetic field dependencies of the SdH amplitude, respectively. The in‐plane effective mass of 2D electrons is in the range between 0.19 m0 and 0.22 m0. Our results for in‐plane effective mass are in good agreement with those reported in the literature (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Superconductivity in MBE grown InN
Authors: Gunes M. , Balkan N. , Tiras E. , Ardali S. , Ajagunna A. O. , Iliopoulos E. , Georgakilas A.
Published: March 2011

We present the experimental investigation of superconductivity in unintentionally doped MBE grown InN samples with various InN film thicknesses. A significant change in resistivity was observed at 3.82 K, for an 1080 nm InN layer with carrier concentration n3D=1.185x1019 cm‐3. However, no significant resistance change was observed in the case of InN samples with carrier density of 1.024x1019 cm‐3, 1.38x1019 cm‐3, and thicknesses of 2070 and 4700 nm, respectively.

The carrier density of all investigated samples was within the range of values between the Mott transition (2x1017 cm‐3) and the superconductivity to metal transition (7x1020 cm‐3). We believe that at lower temperatures (3He) which we cannot achieve with our set‐up, the phase transition in other samples is likely to be observed. The origin of the observed anisotropic type‐II superconductivity is discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conduction and valence band positions versus the Fermi‐level stabilization energy in quaternary dilute nitrides
Authors: Kudrawiec Robert
Published: March 2011

In this paper the author analyze the conduction (valence) band position versus the Fermi‐level stabilization energy (EFS) for quaternary dilute nitrides such as GaInNP, GaInNAs, GaInNSb, GaNPAs, GaNPSb, GaNAsSb, InNPAs, InNPSb and InNAsSb in the whole range of N‐free host content within the method proposed in J. Appl. Phys. 101, 023522 (2007). Since it was found that the Fermi level tends to be pinned close to the EFS in as‐grown dilute nitrides, the information about the conduction band position versus the EFS is important from the viewpoint of native defect formation in III‐V‐N alloys as well as the Schottky contact formation. In this paper III‐V‐N alloys for which the EFS is located into the conduction band are recognized. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stable passivation of InN surface electron accumulation with sulphur treatment
Authors: Bailey L. R. , Veal T. D. , McConville C. F.
Published: March 2011

The effects of treatment with ammonium sulphide ((NH4)2Sx) solution and exposure to air for a month on the electronic properties of InN surfaces has been investigated with high resolution X‐ray photoemission spectroscopy.

The valence band, In 3d, and N 1s X‐ray photoemission spectra show that the surface Fermi level decreases by approximately 0.1 eV following initial (NH4)2Sx‐treatment and does not change position with exposure to air for a period of up to a month. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Black Tea Prevents High Fat Diet‐induced Non‐alcoholic Steatohepatitis
Authors: Karmakar Subhra , Das Dolan , Maiti Anasuya , Majumdar Sangita , Mukherjee Piyal , Das Asankur S. , Mitra Chandan
Published: March 2011

The chemoprotective actions of aqueous black tea extract (BTE) against high‐fat diet (HFD) (60%)‐induced non‐alcoholic steatohepatitis (NASH) were examined in Wistar rats of both sexes. The results indicated that the HFD rats had higher concentrations of serum glucose, cholesterol, triglycerides, low‐density lipoprotein, very low‐density lipoprotein, high‐density lipoprotein and bilirubin than the corresponding control rats. The enzymes serum aspartate aminotransferase and alanine aminotransferase, which are indicators of liver function, also exhibited higher levels of activity in HFD rats. BTE extract supplementation was found to correct such steatohepatitis‐linked biochemical changes. HFD‐induced steatohepatitis was associated with substantial pro‐oxidant conditions in rat liver, as evidenced by the higher content of malondialdehyde, nitric oxide production and glutathione depletion, with a concomitant decrease in liver antioxidant status caused by reducing superoxide dismutase and catalase activity. In addition, rats with steatohepatitis showed a significantly higher expression of inducible nitric oxide synthase, caspase‐3 activity and DNA fragmentation. BTE reversed the changes in the pro‐oxidant and antioxidant status of the liver, and protected against apoptotic, cytogenetic and hepatocellular damage. In summary, these data suggest that nutritional support with antioxidants may be useful in preventing oxidative damage and the progression of NASH. Copyright © 2011 John Wiley & Sons, Ltd.
Protective Role of Tea Polyphenols in Combination against Radiation‐induced Haematopoietic and Biochemical Alterations in Mice
Authors: Hu Yuan , Cao Jing‐Jing , Liu Ping , Guo Dai‐Hong , Wang Ya‐Ping , Yin Jian , Zhu Ying , Rahman Khalid
Published: March 2011

The purpose of this study was to investigate the radioprotective effects of tea polyphenols (TPs) in various combinations against radiation‐induced damage in mice. Mice were divided into different groups: non‐irradiated control, irradiated control, amifostine (43.6 mg/kg, i.v. 30 min before irradiation; positive control) and various combinations of tea polyphenols in different doses. The radioprotective effect on the haematopoietic system, serum cytokines and endogenous antioxidant enzymes were studied. TP50, containing approximately 50% of (‐)‐epigallochatechin‐3‐gallate in addition to other catechins, showed the greatest radioprotective effect against radiation‐induced changes in haematological parameters (red blood cell count, white blood cell count and haemoglobin), and maintained the spleen and thymus indices unchanged (spleen or thymus weight/body weight × 1000). Tea polyphenols also significantly decreased radiation‐induced lipid peroxidation (malondialdehyde levels), elevated endogenous antioxidant enzymes (superoxide dismutase) and reduced the serum cytokines which were elevated in radiation‐induced toxicity. This evidence shows the potential of tea polyphenols, particularly in the combination found in TP50, as radioprotectors in mice, especially regarding recovery of the haematopoietic system, antioxidant potential activity and reduction of inflammatory cytokines. Copyright © 2011 John Wiley & Sons, Ltd.
An extended specification of flow‐dependent background error variances in the Météo‐France global 4D‐Var system
Authors: Raynaud Laure , Berre Loïk , Desroziers Gérald
Published: April 2011

A variational ensemble assimilation has been developed at Météo‐France to provide errors ‘of the day’ to the operational 4D‐Var assimilation of the Arpège model. In the reference Arpège system (operational until April 2010), ensemble‐based variances are used for vorticity and for the associated balanced parts of mass and divergence, while variances of the unbalanced parts remain static and horizontally homogeneous, and humidity variances are calculated with an empirical flow‐dependent formula. This article presents some diagnostic and impact studies to examine the effects of extending the specification of flow‐dependent ensemble‐based variances to all variables in the minimization. The extended flow‐dependent variances derived from the ensemble are first compared with the reference system values. It is observed that the flow‐dependence of local variances of all variables tends to be strengthened with the extended specification. This is particularly noticeable for surface pressure variances in the vicinity of mid‐latitude storms and tropical cyclones. The impact of using variances ‘of the day’ for all analysis variables is examined through analysis/forecast experiments over a 1‐month period. The global impact of this extended specification is neutral to positive. Results suggest that the new variances are likely to produce localized (in space and time) positive impacts, most likely connected with dynamically active systems. This is supported by a case study of an intense storm that hit the northern part of France on February 2009. It is observed that the extended flow‐dependent information improves the 48 h surface pressure forecast, by correcting both position and intensity errors. Copyright © 2011 Royal Meteorological Society
Process improvement in healthcare: overall resource efficiency
Authors: de Mast Jeroen , Kemper Benjamin , Does Ronald J. M. M. , Mandjes Michel , van der Bijl Yohan
Published: April 2011

This paper aims to develop a unifying and quantitative conceptual framework for healthcare processes from the viewpoint of process improvement. The work adapts standard models from operation management to the specifics of healthcare processes. We propose concepts for organizational modeling of healthcare processes, breaking down work into micro processes, tasks, and resources. In addition, we propose an axiological model which breaks down general performance goals into process metrics. The connexion between both types of models is made explicit as a system of metrics for process flow and resource efficiency. The conceptual models offer exemplars for practical support in process improvement efforts, suggesting to project leaders how to make a diagrammatic representation of a process, which data to gather, and how to analyze and diagnose a process's flow and resource utilization. The proposed methodology links on to process improvement methodologies such as business process reengineering, six sigma, lean thinking, theory of constraints, and total quality management. In these approaches, opportunities for process improvement are identified from a diagnosis of the process under study. By providing conceptual models and practical templates for process diagnosis, the framework relates many disconnected strands of research and application in process improvement in healthcare to the unifying pursuit of process improvement. Copyright © 2011 John Wiley & Sons, Ltd.
URBANIZATION IMPAIRS SURFACE WATER QUALITY: EUTROPHICATION AND METAL STRESS IN THE GRAND CANAL OF CHINA
Authors: Yu S. , Yu G. B. , Liu Y. , Li G. L. , Feng S. , Wu S. C. , Wong M. H.
Published: March 2011

Rapid urbanization leads to degradations upon water quality via eutrophication and pollution, but there are a lack of studies on patterns of water quality change to urbanization by level or process. China has achieved the most rapid urbanization in the world within the past three decades, and its urban development is diverse at level. Nine towns and cities at various development levels along the historic Grand Canal (approximately 1500 years old) were selected to reveal direct linkages between surface water quality and extent of urbanization. Surface water quality in the urban sections of the Grand Canal was impaired by both eutrophic nitrogen and phosphorus and metals. Although metals mostly remained at concentrations permissible to the Chinese National Environmental Standard for Surface Water Quality (GB3838‐2002), the concentrations of metals in most urban canal water might impose an unacceptable effect on aquatic communities according to the Criterion Continuous Concentration from the National Recommended Water Quality Criteria for Priority Toxic Pollutants (US EPA 2006). The loadings of metals in the urban canal were found relating to local industrial activities. The level of urbanization, in this study, was significantly related to water quality parameters in a descending order of electrical conductivity > nutrients > metals. This study suggests that significant mitigation strategies are required for the Grand Canal of China for a sustainable urbanization goal. Copyright © 2011 John Wiley & Sons, Ltd.
Carbon Nanosheets: Mechanically Stacked 1‐nm‐Thick Carbon Nanosheets: Ultrathin Layered Materials with Tunable Optical, Chemical, and Electrical Properties (Small 7/2011)
Authors: Nottbohm Christoph T. , Turchanin Andrey , Beyer André , Stosch Rainer , Gölzhäuser Armin
Published: April 2011

Carbon nanosheets are mechanically stable, free‐standing two‐dimensional materials with a thickness of ≈1 nm and well defined physical and chemical properties. They are made by radiation‐induced cross‐linking of aromatic self‐assembled monolayers. Herein, a route is presented to the scalable fabrication of multilayer nanosheets with tunable electrical, optical, and chemical properties on insulating substrates. Stacks of up to five nanosheets with sizes of ≈1 cm2 on oxidized silicon are studied. Their optical characteristics are investigated by visual inspection, optical microscopy, UV–vis reflection spectroscopy, and model calculations. Their chemical composition is studied by X‐ray photoelectron spectroscopy. The multilayer samples are then annealed in an ultrahigh vacuum at various temperatures up to 1100 K. A subsequent investigation by Raman, X‐ray photoelectron, and UV–vis reflection spectroscopy, as well as by electrical four‐point probe measurements, demonstrates that the layered nanosheets transform into nanocrystalline graphene. This structural and chemical transformation is accompanied by changes in the optical properties and electrical conductivity and opens up a new path for the fabrication of ultrathin functional conductive coatings.
Microfluidics: Nanostructuring of Titania Thin Films by a Combination of Microfluidics and Block‐Copolymer‐Based Sol–Gel Templating (Small 7/2011)
Authors: Rawolle Monika , Ruderer Matthias A. , Prams Stefan M. , Zhong Qi , Magerl David , Perlich Jan , Roth Stephan V. , Lellig Philipp , Gutmann Jochen S. , Müller‐Buschbaum Peter
Published: April 2011

Sol–gel templating of titania thin films with the amphiphilic diblock copolymer poly(dimethyl siloxane)‐block‐methyl methacrylate poly(ethylene oxide) is combined with microfluidic technology to control the structure formation. Due to the laminar flow conditions in the microfluidic cell, a better control of the local composition of the reactive fluid is achieved. The resulting titania films exhibit mesopores and macropores, as determined with scanning electron microscopy, X‐ray reflectivity, and grazing incidence small angle X‐ray scattering. The titania morphology has three features that are beneficial for application in photovoltaics: 1) a large surface‐to‐volume ratio important for charge generation with disordered hexagonally arranged mesopores of 25 nm size and a film porosity of up to 0.79, 2) enhanced light scattering that enables the absorption of more light, and 3) a dense titania layer with a thickness of about 6 nm at the substrate (bottom electrode) to prevent short circuits. An optical characterization complements the structural investigation.
Entwicklung hybrider Stahl‐Glas‐Träger
Authors: Abeln Björn , Preckwinkel Eva
Published: April 2011

Immer höhere Anforderungen an die Transparenz von Bauwerken führen zu einer stetigen Weiterentwicklung von tragenden Glaselementen, wobei dem Glas neben seiner ausfachenden Funktion mehr und mehr konstruktive Aufgaben zugedacht werden. Aktuelle Entwicklungen stellen die hybriden Stahl‐Glas‐Träger dar, bei denen schlanke Stahlflansche und Glasstege mittels geklebter Schubfugen zu einem “I”‐Träger zusammengesetzt werden [1]. Der Vorteil der linienförmigen Verklebung liegt hierbei in der gleichmäßigen Lasteinleitung in das Glasbauteil. Die Wahl des eingesetzten Klebstoffsystems trägt in Abhängigkeit seiner mechanischen Eigenschaften maßgeblich zum Tragverhalten des Verbundquerschnittes bei. Ebenso ist der Fugengeometrie eine große Bedeutung hinsichtlich der Tragfähigkeit und Herstellbarkeit zuzuordnen. Allerdings bestimmen Langzeiteffekte, wie Alterung des Klebstoffs und zeitabhängiges Tragverhalten, die Bemessung. Der Beitrag gibt einen Überblick über das systematische Vorgehen zur Untersuchung des Tragverhaltens und nennt wichtige Kriterien und Anforderungen beim Entwurf hybrider Stahl‐Glas‐Träger in Hin blick auf eine optimierte Ausnutzung der einzelnen Komponenten.

Development of hybrid steel‐glass‐beams. Increasing higher requirements for transparent and filigree structures result in continuous development and improvement of load‐bearing glass elements, not only in a classic way being a space enclosing element but also increasingly offering load carrying functions. To realize architectural attractive transparent and lightweight constructions bonded hybrid steel‐glass beams have been developed, composed of slim steel flanges and glass webs which were assembled to ”I”‐beams using adhesives. The adhesive system significantly account for the structural behavior of the bonded composite section. Furthermore the joining geometry is of great importance concerning load carrying capacity and producibility but the design is governed by long‐term effects like ageing, creeping and time dependent load‐carrying behavior. This contribution shows the general systematic approach for the analysis of the load bearing behavior of hybrid steel‐glass beams and introduces important criteria and requirements for the design and its mechanical properties focused on an optimized exploitation of the components.
Ultraschallangeregte Thermografie zur Risserkennung im Stahlbau — Ein Verfahren auf dem Prüfstand
Authors: Ummenhofer Thomas , Plum Robin
Published: April 2011

Die ultraschallangeregte Infrarotthermografie stellt ein innovatives Verfahren zur Erkennung von rissartigen Fehlstellen in metallischen Bauteilen dar. Zu Schwingungen angeregte Rissufer reiben und schlagen gegeneinander. Die lokal dissipierte Energie erwärmt den Riss und macht ihn thermografisch sichtbar. Obwohl die Methode seit einigen Jahren Forschungsgegenstand im Bereich der Zerstörungsfreien Prüfung ist, wurde sie noch nicht im Bauwesen verwendet. Dieser Beitrag stellt das Prinzip des Prüfverfahrens vor und zeigt anhand ausgewählter Forschungsergebnisse die Besonderheiten und Probleme auf, die bei der Bauteilprüfung zu beachten sind. Neben den Einflüssen der Anregungsfrequenz und des Vorspannzustandes wird untersucht, inwieweit eine wiederholte Ultraschallanregung schädigend wirkt. Da die Zusammenhänge der involvierten dissipativen Effekte, welche die Risserkennung erst ermöglichen, noch nicht im Detail geklärt sind, wird ein vereinfachter Ansatz für die numerische Simulation des Prüfverfahrens vorgestellt, mit dem bisher gute Ergebnisse erzielt wurden.

Ultrasound excited thermography applied to constructional steelwork — An emerging crack detection methodology. Ultrasound excited thermography is an innovative method for the detection of crack‐like flaws in metal components. When crack faces rub and clap against each other due to vibrational excitation the dissipated energy leads to a local heating of the crack. This way the defect can be detected by means of an infrared camera. Despite of being a research topic in the field of nondestructive testing for several years, the technique has not been transferred to civil engineering, yet. This article presents the NDT method and discusses the essential characteristics and problems which are of concern when testing steel members. The influences of the excitation frequency and the prestressing conditions on the crack detectability as well as possible damaging effects due to repeated insonification are investigated. Since the physical effects involved in the energy dissipation at the crack region are not understood in detail, a simplified numerical simulation approach is presented that leads to good agreement of experimental and numerical results.