bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of pharmacodynamic principles to inform β‐lactam dosing: “S” does not always mean success
Authors: Lodise Thomas P. , Butterfield Jill
Published: January 2011

Dose optimization is one of the key strategies for enhancing antimicrobial stewardship. There have been tremendous strides in our understanding of antibiotic exposure‐response relationships over the past 25 years. For many antibiotics, the “pharmacodynamic” or the exposure variable associated with outcome has been identified. With advances in mathematical modeling, it is possible to apply our understanding of antimicrobial pharmacodynamics (PD) into clinical practice and design empirical regimens that have a high probability of achieving the PD target linked to effect. By optimizing antibiotic doses to achieve PD targets predictive of efficacy, clinicians can improve care and minimize drug toxicity. For β‐lactams, the PD parameter most predictive of maximal bactericidal activity is the duration of time free drug concentrations remain above the minimum inhibitory concentration (MIC) during the dosing interval (fT > MIC). Unfortunately, the conventional intermittent β‐lactam dosing schemes often used in practice have suboptimal PD profiles. Prolonging the infusion time of β‐lactams is one method to maximize the probability of achieving concentrations in excess of the MIC for the majority of the dosing interval, especially against pathogens with elevated MIC values. Prolonged infusions of intravenous β‐lactams are not only associated with improved probability of target attainment (PTA) profiles but offer possible cost savings and greater potential for reducing emergence of resistance relative to intermittent infusions. Journal of Hospital Medicine 2011;6:S16‐S23. ©2011 Society of Hospital Medicine.
Antimicrobial stewardship for inpatient facilities
Authors: Ohl Christopher A. , Luther Vera P.
Published: January 2011

Antibiotic stewardship aims to improve patient care and reduce unwanted consequences of antimicrobial overuse or misuse, including lowered efficacy, emergence of antimicrobial resistance, development of secondary infections, adverse drug reactions, increased length of hospital stay, and additional healthcare costs. Recent guidelines make specific recommendations for the development of institutional programs to enhance antimicrobial stewardship. Optimally, such programs should be comprehensive, multidisciplinary, supported by hospital and medical staff leadership, and should employ evidence‐based strategies that best fit local needs and resources. An infectious diseases physician and clinical pharmacist with infectious diseases training are recommended as core members of the multidisciplinary team, although a hospitalist with interest (and perhaps additional training) in antimicrobial therapy may be able to fill the void. Program directors and core members should be compensated for their time. Principal proactive strategies—with evidence supporting their consideration—include prospective audits, with intervention and feedback, formulary restriction, and preauthorization. Other strategies include persistent one‐on‐one education, guidelines adapted to local needs, and informatics to support clinical decision making. Intervention goals are to prevent unnecessary antimicrobial starts, to streamline or de‐escalate therapy early in its course, and to convert from parenteral to oral therapy, optimize dosing, and ensure the appropriate length of therapy. Most community hospitals, if sufficiently resourced, should be able to implement a successful antimicrobial stewardship program. Evidence suggests that good antimicrobial stewardship can lead to less overall and inappropriate antimicrobial use, lower drug‐related costs, reductions inClostridium difficile–associated disease, and, in some studies, less emergence of antimicrobial resistance. Journal of Hospital Medicine 2011;6:S4‐S15 ©2011 Society of Hospital Medicine.
A framework for the evaluation of the South Asian summer monsoon in a regional climate model applied to REMO
Authors: Saeed Fahad , Hagemann Stefan , Jacob Daniela
Published: January 2011

Considering the complex spatial and vertical structure of the South Asian summer monsoon (SASM), the validation of a regional climate model (RCM) dealing with only a few surface variables is considered insufficient. Therefore, we have proposed an evaluation framework for the better assessment of the capability of an RCM in capturing the fundamental structure of SASM. This framework has been applied to the regional climate model REMO using ERA40 lateral boundary conditions for the period 1961–2000.

The application of framework yielded satisfactory performance of REMO in capturing the lower, middle, and upper component of the SASM circulation. REMO has higher correlation between different SASM indices as compared to ERA40, showing its ability in capturing the dynamical link between these indices better than ERA40. We have employed different criteria for the assessment of the monsoon onset, and the movement of the Intertropical Convergence Zone (ITCZ) during the boreal summer and REMO has captured these phenomena reasonably well. The model has also shown the association of the meridional temperature gradient with the easterly shear of zonal winds. These results lead us to the conclusion that REMO is well suited for long‐term climate change simulations to examine projected future changes in the complex SASM system. Copyright © 2011 Royal Meteorological Society
Laboratory test results after living liver donation in the adult-to-adult living donor liver transplantation cohort study a,b,c
Authors: Trotter James F. , Gillespie Brenda W. , Terrault Norah A. , Abecassis Michael M. , Merion Robert M. , Brown Robert S. , Olthoff Kim M. , Hayashi Paul H. , Berg Carl L. , Fisher Robert A. , Everhart James E.
Published: January 2011

Information on the long-term health of living liver donors is incomplete. Because changes in standard laboratory tests may reflect the underlying health of donors, results before and after donation were examined in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL). A2ALL followed 487 living liver donors who donated at 9 US transplant centers between 1998 and 2009. The aminotransferase [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)] and alkaline phosphatase (AP) activities, bilirubin, international normalized ratio (INR), albumin, white blood cell count (WBC), hemoglobin (HGB), platelet count, ferritin, serum creatinine (SCR), and blood urea nitrogen (BUN) were measured at the evaluation and after donation (1 week, 1 month, 3 months, 1 year, and yearly thereafter). Repeated measures models were used to estimate median laboratory values at each time point and to test for differences between values at the evaluation (baseline) and postdonation time points. Platelet counts were significantly decreased at every time point in comparison with the baseline, and at 3 years, they were 19% lower. Approximately 10% of donors had a platelet count < 150 × 1000/mm3 2 to 3 years post-donation. Donors with a platelet count ≤ 150 × 1000/mm3 at 1 year had significantly lower mean platelet counts (189 ± 32 × 1000/mm3) versus the remainder of the cohort (267 ± 56 × 1000/mm3, P < 0.0001) at the evaluation. Statistically significant differences compared to the evaluation values were noted for AST, AP, INR, and albumin through the first year, although most measurements were in the normal range. The median values for WBC, HGB, ferritin, albumin, SCR, BUN, and INR were not substantially outside the normal range at any time point. In conclusion, after 3 months, most laboratory values return to normal among right hepatic lobe liver donors, with a slower return to baseline levels for AST, AP, INR, and albumin. Persistently decreased platelet counts warrant further investigation.
Liver Transpl, 2011. © 2011 AASLD.
Is cytomegalovirus infection dangerous in cytomegalovirus-seropositive recipients after liver transplantation?
Authors: Kim Jong Man , Kim Sung-Joo , Joh Jae-Won , Kwon Choon Hyuck David , Song Sanghyun , Shin Milljae , Moon Ju Ik , Kim Gaab Soo , Hong Seung Heui , Lee Suk-Koo
Published: January 2011

Cytomegalovirus (CMV) infections contracted after liver transplantation put patients at an increased risk of morbidity and mortality. We analyzed the effects of CMV infection by time of onset, mortality, and graft failure risk factors in liver recipients who were CMV donor-positive/recipient-positive (D+/R+). We reviewed 618 medical records for consecutive adult liver transplant cases. CMV pp65 antigenemia assays to determine patient CMV status were administered monthly. The incidences of CMV infection and disease were 55.7% (344 of 618 records) and 5.5% (34 of 618 records), respectively. The differences in patient survival and graft failure rates for CMV-infected and CMV-uninfected patients were not significant (P = 0.707 and P = 0.973), but the rates were lower in patients with CMV disease than in CMV-uninfected patients (P = 0.005 and P = 0.030, respectively). The recurrence of hepatitis B virus and hepatocellular carcinoma, hepatic dysfunction, infection, numerous pp65-staining cells, and CMV disease were found to be the risk factors for mortality and graft failure in CMV D+/R+ adult liver transplant patients. In conclusion, the occurrence of CMV disease, and not asymptomatic CMV infection, was a risk factor for mortality and graft failure in adult liver transplant recipients with CMV D+/R+.
Liver Transpl, 2011. © 2011 AASLD.
Epigenetic profile of developmentally important genes in bovine oocytes
Authors: Heinzmann J. , Hansmann T. , Herrmann D. , Wrenzycki C. , Zechner U. , Haaf T. , Niemann H.
Published: January 2011

Assisted reproductive technologies are associated with an increased incidence of epigenetic aberrations, specifically in imprinted genes. Here, we used the bovine oocyte as a model to determine putative epigenetic mutations at three imprinted gene loci caused by the type of maturation, either in vitro maturation (IVM) in Tissue Culture Medium 199 (TCM) or modified synthetic oviduct fluid (mSOF) medium, or in vivo maturation. We applied a limiting dilution approach and direct bisulfite sequencing to analyze the methylation profiles of individual alleles (DNA molecules) for H19/IGF2, PEG3, and SNRPN, which are each associated with imprinting defects in humans and/or the mouse model, and are known to be differentially methylated in bovine embryos. Altogether, we obtained the methylation patterns of 203 alleles containing 4,512 CpG sites from immature oocytes, 213 alleles with 4,779 CpG sites from TCM‐matured oocytes, 215 alleles/4,725 CpGs in mSOF‐matured oocytes, and 78 alleles/1,672 CpGs from in vivo‐matured oocytes. The total rate of individual CpGs and entire allele methylation errors did not differ significantly between the two IVM and the in vivo group, indicating that current IVM protocols have no or only marginal effects on these critical epigenetic marks. Furthermore, the mRNA expression profiles of the three imprinted genes and a panel of eight other genes indicative of oocyte competence were determined by quantitative real‐time PCR. We found different mRNA expression profiles between in vivo‐matured oocytes versus their in vitro‐matured counterparts, suggesting an influence on regulatory mechanisms other than DNA methylation. Mol. Reprod. Dev. 78:188–201, 2011. © 2011 Wiley‐Liss, Inc.
Optimization of spiral‐based pulse sequences for first‐pass myocardial perfusion imaging
Authors: Salerno Michael , Sica Christopher T. , Kramer Christopher M. , Meyer Craig H.
Published: January 2011

Although spiral trajectories have multiple attractive features such as their isotropic resolution, acquisition efficiency, and robustness to motion, there has been limited application of these techniques to first‐pass perfusion imaging because of potential off‐resonance and inconsistent data artifacts. Spiral trajectories may also be less sensitive to dark‐rim artifacts that are caused, at least in part, by cardiac motion. By careful consideration of the spiral trajectory readout duration, flip angle strategy, and image reconstruction strategy, spiral artifacts can be abated to create high‐quality first‐pass myocardial perfusion images with high signal‐to‐noise ratio. The goal of this article was to design interleaved spiral pulse sequences for first‐pass myocardial perfusion imaging and to evaluate them clinically for image quality and the presence of dark‐rim, blurring, and dropout artifacts. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Improved myo‐inositol detection through Carr–Purcell PRESS: A tool for more sensitive mild cognitive impairment diagnosis
Authors: Hancu Ileana , Gillen Robert , Cowan John , Zimmerman Earl A.
Published: January 2011

A 3‐T study is presented, comparing the ability of two1H spectroscopy pulse sequences, Carr–Purcell point resolved spectroscopy (CPRESS; TE = 45 msec), and conventional PRESS (TE = 35 msec), to separate between groups of 20 normal control (NC) and 20 mild cognitive impairment (MCI) subjects. Both sequences showed higher myo‐inositol (mI) and mI/N‐acetyl‐aspartate (NAA) levels in the posterior cingulate gyrus of the MCI subjects. The increased intrasubject repeatability of mI and mI/NAA CPRESS measurements (∼6% vs. 9% for PRESS) translated into decreased intraclass variability. A 22% intraclass mI PRESS variability was reduced to 16% for CPRESS, and an 18% intraclass mI/NAA PRESS variability was reduced to 12% for CPRESS for the group of NC subjects. Similar results were observed for the MCI subjects. Decreased intraclass variability led to improved separation between NC and MCI subjects (P= 0.017 for PRESS andP< 0.0001 for CPRESS mI/NAA, the best NC/MCI discriminant for each method). Seventy‐five percent sensitivity at eighty percent specificity was demonstrated by mI/NAA CPRESS measurements in separating NC from MCI subjects. High correlations were also observed between subject performance on a number of neuropsychological tests (probing verbal memory, visuoconstruction performance, and visual motor integration) and the mI/NAA ratio; higher correlation coefficients (with stronger statistical significance) were consistently evident for CPRESS than for PRESS data. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Altered Hippo signalling in polycystic kidney disease
Authors: Happé Hester , van der Wal Annemieke M , Leonhard Wouter N , Kunnen Steven J , Breuning Martijn H , de Heer Emile , Peters Dorien JM
Published: January 2011

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive deterioration of renal function and formation of cysts, and is an important cause of end‐stage renal disease. Previously we showed that tubular epithelial injury accelerates cyst formation in inducible Pkd1‐deletion mice. In these mice, expression of the planar cell polarity (PCP) component Four‐jointed (Fjx1) is decreased during epithelial repair, while in control mice Fjx1 expression is increased and may be required during tissue regeneration. In cystic kidneys, however, Fjx1 expression is also increased. Besides a PCP component, Four‐jointed is also implicated in the Hippo‐signalling pathway. This pathway is involved in organ size control by regulating proliferation and apoptosis. The role of Hippo signalling, together with the opposing expression pattern of Fjx1 during epithelial repair and at cystic stages, triggered us to investigate the activity of the Hippo pathway during these processes. Therefore, we examined its final effector molecule, the transcriptional co‐activator Yes‐associated protein (YAP) and observed that during tissue repair, YAP expression was not different between Pkd1‐deletion mice and controls, ie during tissue regeneration YAP expression was increased and predominantly localized in the cytoplasm but normalized after tissue repair. At a later stage, however, in cystic epithelia and epithelia of dilated tubules, strong nuclear YAP accumulation was observed, accompanied by up‐regulation of the YAP transcriptional targets Birc‐3, Ctgf, InhbA, and Fjx1. Altered activity of the Hippo pathway was confirmed in renal tissues from human ADPKD and ARPKD patients, as well as in cystic renal tumours. Our data strengthen the concept that during epithelial repair Four‐jointed is involved in PCP signalling, while in cystic kidneys it is related to Hippo signalling and cyst growth. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Autoantibody‐induced intestinal inflammation and weight loss in experimental epidermolysis bullosa acquisita
Authors: Ishii Norito , Recke Andreas , Mihai Sidonia , Hirose Misa , Hashimoto Takashi , Zillikens Detlef , Ludwig Ralf J
Published: January 2011

Type VII collagen (COL7) is a major constituent of the cutaneous basement membrane. Loss of tolerance to COL7 leads to the blistering skin disease epidermolysis bullosa acquisita (EBA). Antibodies to COL7 have also been detected in patients with inflammatory bowel disease (IBD), yet reports on the expression of COL7 in the gut are controversial and a pathogenic relevance of anti‐COL7 autoantibodies in IBD has not been demonstrated. We therefore characterized the expression patterns of COL7 in murine gastrointestinal organs and investigated if anti‐COL7 antibodies induce an inflammatory response in the gut. COL7 expression was analysed on the mRNA and protein levels. Mice were injected with rabbit anti‐murine COL7 IgG (passive EBA) or immunized with a fragment of murine COL7 (active EBA). COL7 was found to be expressed in buccal mucosa, oesophagus, stomach, small intestine, and colon. In addition to skin blistering, in both passive and active EBA, autoantibodies bound to the gastrointestinal basement membrane, fixed complement, and led to recruitment of leukocytes. Furthermore, blister formation was observed in the oesophagus (40%/38% of mice in passive/active model), stomach (40%/63%), small intestine (20%/13%), and colon (20%/13%). Compared to control animals, we found a significantly reduced body weight in diseased mice, suggesting that autoantibody‐induced gastrointestinal inflammation is clinically relevant. Those observations may help us to understand the co‐incidence of IBD with EBA, and vice versa: The inflammatory response in IBD might expose novel antigens (COL7), which leads to the formation of anti‐COL7 antibodies. On the contrary, anti‐COL7 antibody‐induced gastrointestinal inflammation might pave the way for IBD pathogenesis. In summary, our results provide strong evidence that COL7 is expressed in different portions of the gut and that anti‐COL7 antibodies induce distinct gastrointestinal tissue damage. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Consistency between causality assessments obtained with two scales and their agreement with clinical judgments in hepatotoxicity
Authors: Miljkovic Milena M. , Dobric Silva , Dragojevic‐Simic Viktorija
Published: January 2011

Purpose

Reliability and usefulness of scales for causality assessment in hepatotoxicity have not been fully explored. The goal of this study was to examine consistency between causality assessments obtained with two commonly used scales and their agreement with initial clinical assessments in hepatotoxicity reported in Serbia, and to review usefulness of these scales.

Methods

We compared the two scales (CIOMS/RUCAM and NARANJO) in 80 cases reported during 1995–2009. The initial clinical assessments performed at the time of reporting served as a control for comparison with the subsequent causality assessments. The agreement between obtained causality assessments and the initial clinical assessments were analysed by Kappa weighted (Kw) statistical test.

Results

In the 80 cases, the NARANJO scale showed better agreement with the initial clinical assessments (Kw: 0.62) than the CIOMS/RUCAM scale (Kw: 0.50) with moderate mutual agreement (Kw: 0.58). Results for 69 cases reported before the start of the study showed the same. In 11 cases reported in 2009 (after the start of the study) the CIOMS/RUCAM scale showed better agreement with the initial clinical assessments (Kw: 0.80) than the NARANJO scale (Kw: 0.70) with perfect mutual agreement (Kw: 1.0).

Conclusion

The two scales showed good similarity and the same was true when their outcomes were compared with the clinical judgments provided by the reporting physicians. Both scales may be useful in pharmacovigilance and clinical practice, but the CIOMS/RUCAM scale provides more specific data. Our results also confirmed that the quality of data and documentation influence the reliability of the method. Copyright © 2011 John Wiley & Sons, Ltd.
Formation and morphology development of poly(butylene terephthalate) nanofibers from poly(butylene terephthalate)/cellulose acetate butyrate immiscible blends
Authors: Li Mufang , Xiao Ru , Sun Gang
Published: January 2011

Nano‐scale poly(butylene terephthalate) (PBT) fibers were prepared from PBT/cellulose acetate butyrate (CAB) immiscible polymer blends due to in situ microfibrillar formation during a melt extruding process. The morphological development of the dispersed phase was studied with samples collected at different zones in a twin screw extruder. It was found that the holistic developmental trends of PBT dispersed phase were nearly the same. Fibers began to form even under the shear flow of the twin‐screw extruder. The morphology developmental mechanism of the dispersed phase involved the formation of sheets, holes and network structures, then the size reduction and formation of nanofibers. The effect of viscosity ratio, blend ratio, and shear rate on the morphology evolution was also studied by analyzing the shape and size distribution of the samples. The diameter distribution of the nanofibers could be affected by viscosity ratio, blend ratio, and shear rate. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Cognitive‐behavioral therapy for children with autism spectrum disorders
Authors: Rotheram‐Fuller Erin , MacMullen Laura
Published: January 2011

Autism spectrum disorders (ASD) represent a continuum of cognitive and social problems that vary considerably in both impact and presentation for each child affected. Although successful interventions have been developed that target specific skill deficits often exhibited by children with autism, many of those interventions are exclusively behavioral in nature, and do not address the cognitive components of presenting problems. The use of cognitive‐behavioral therapy (CBT) to address issues related to ASD, however, has been increasing. More specifically, CBT interventions have often been used to address issues of anxiety for children with ASD, and these promising results may be useful to inform practices in schools. This review examines existing literature on CBT interventions that have been evaluated with children with ASD and suggests methods and implications for adapting these interventions for use within the school setting. © 2011 Wiley Periodicals, Inc.
Walking speed and peak plantar pressure distribution during barefoot walking in persons with diabetes
Authors: Ko Mansoo , Hughes Lynne , Lewis Harriet
Published: January 2011

Background. The impact of walking speed has not been evaluated as a feasible outcome measure associated with peak plantar pressure (PPP) distribution, which may result in tissue damage in persons with diabetic foot complications. The objective of this pilot study was to determine the walking speed and PPP distribution during barefoot walking in persons with diabetes. Methods. Nine individuals with diabetes and nine age–gender matched individuals without diabetes participated in this study. Each individual was marked at 10 anatomical landmarks for vibration and tactile pressure sensation tests to determine the severity of sensory deficits on the plantar surface of the dominant limb foot. A steady state walking speed, PPP, the fore and rear foot (F/R) PPP ratio and gait variables were measured during barefoot walking. Results. Persons with diabetes had a significantly slower walking speed than the age–gender matched group resulting in a significant reduction of PPP at the F/R foot during barefoot walking (p < 0.05). There was no significant difference in F/R foot PPP ratio in the diabetic group compared with the age–gender matched group during barefoot walking (p > 0.05). There was a significant difference between the diabetic and non‐diabetic groups for cadence, step time, toe out angle and the anterior–posterior excursion (APE) for centre of force (p < 0.05). Conclusion. Walking speed may be a potential indicator for persons with diabetes to identify PPP distribution during barefoot walking in a diabetic foot. However, the diabetic group demonstrated a more cautious walking pattern than the age–gender matched group by decreasing cadence, step length and APE, and increasing step time and toe in/out angle. People with diabetes may reduce the risk of foot ulcerations as long as they are able to prevent severe foot deformities such as callus, hammer toe or charcot foot. Copyright © 2011 John Wiley & Sons, Ltd.
Oxygen annealing for deuterium‐doped indium tin oxide thin films
Authors: Okada Koichi , Kohiki Shigemi , Luo Suning , Kohno Atsushi , Tajiri Takayuki , Ishii Satoshi , Sekiba Daiichiro , Mitome Masanori , Shoji Fumiya
Published: January 2011

Deuterium‐doped indium tin oxide films, fabricated by dc plasma deposition in sputter gas consisting of deuterium and argon, were annealed at 300 °C for 40 min in flowing oxygen gas by using tubular gold image furnace. On oxygen annealing, the optical transparency of the film deposited at the gas pressure ratio of deuterium to argon of 3.6% increased from ≈30 to 60% at the wavelength of 600 nm, although that of the films deposited at the ratios of 1 and 1.5% slightly decreased from 88 to 80% and from 85 to 77%, respectively. The resistivity of the films at room temperature, ranged from 2 × 10−4 to 1.4 × 10−3 Ω cm corresponding to the gas pressure ratio from 1 to 3.6%, was almost the same before and after the annealing for each film. A change in morphology toward a smoother surface by the oxygen annealing was apparent especially for the film with the gas pressure ratio of 3.6%. Agglomeration of randomly oriented grains with diameters of <100–200 nm observed before the annealing disappeared on annealing. A smoother surface is responsible for higher transparency of the annealed films that contained densely populated hydroxyl bond before the annealing.

magnified image

Oxygen annealing at 300 °C enlarged the optical transmittance (left panel) but decreased the population of hydrogen‐bonded oxygen (right panel) of the indium tin oxide thin film fabricated by dc plasma deposition in sputter gas containing deuterium of 3.6%.
Narrow sintering temperature window for (K, Na)NbO3‐based lead‐free piezoceramics caused by compositional segregation
Authors: Fang Jian , Wang Xiaohui , Zuo Ruzhong , Tian Zhibin , Zhong Caifu , Li Longtu
Published: January 2011

In this paper, a typical Li‐ and Ta/Sb‐modified alkaline niobate‐based ceramics prepared by conventional sintering were investigated in terms of different sintering temperatures and dwelling times. Compositional segregation phenomenon is found to exist in the alkaline niobate‐based ceramics sintered at the temperatures above their melting points. As a result, microstructures of the ceramics become nonuniform, and electrical properties of them are degraded. Results indicate that compositional segregation is also a factor in the narrow sintering temperature window for alkaline niobate‐based ceramics.
Characterization of ferromagnetism around interfaces by rear‐incident magneto‐optic Kerr effect
Authors: Tsubouchi Kenta , Ohkubo Isao , Oshima Masaharu
Published: January 2011

Understanding and controlling of magnetic properties around interfaces can improve the performances of magnetic devices such as magnetic tunneling junction. We propose characterization of ferromagnetism around interface by rear‐incident magneto‐optic Kerr effect (MOKE). In order to establish a rear‐incident MOKE technique, effects of absorption, reflection, and Faraday rotation by substrates have been carefully investigated on Ni80Fe20 thin films deposited on various substrates. Differences of Kerr rotation angle caused by effects of absorption and reflection of the substrates were negligibly small. Measurements of Kerr hystereses were performed without negative influence of Faraday rotation in substrates with Verdet constant smaller than 0.05 rad/Tmm such as SiO2, glass, and SrTiO3, shows that rear‐incident MOKE can be used for evaluation of ferromagnetism around interfaces.
Dynamics of quantum dots with strong electron phonon coupling: Correlation expansion vs. path integrals
Authors: Vagov A. , Croitoru M. D. , Axt V. M. , Machnikowski P. , Kuhn T.
Published: January 2011

We have simulated coherent control signals from quantum dots for carrier phonon interactions covering the low as well as the strong coupling limit. Calculations using the correlation expansion for phonon assisted density matrices are compared with numerically exact results obtained from a time dependent path‐integral approach. Even at elevated coupling strengths both calculations agree well for not too high temperatures. For pulse lengths and delay times shorter than the phonon induced memory time the correlation expansion gives good results in almost all cases. For strong coupling and/or high temperatures drastic discrepancies emerge. Interestingly, the correlation expansion works better at high pulse areas, which is related to a dynamic decoupling of electron and phonon dynamics in strongly confined systems.
Inductive equation of motion approach for a semiconductor QD‐QED: Coherence induced control of photon statistics
Authors: Kabuss Julia , Carmele Alexander , Richter Marten , Chow Weng W. , Knorr Andreas
Published: January 2011

This paper presents an inductive method for the microscopic description of quantum dot (QD) QED. Our description reproduces known effects up to an arbitrary accuracy, and is extendable to typical semiconductor effects, like many electron‐ and phonon‐interactions. As an application, this method is used to theoretically examine quantum coherence phenomena and their impact on photon statistics for a Λ‐type semiconductor QD strongly coupled to a single mode cavity and simultaneously excited with an external laser.
Theoretical study on the interaction between C3 molecular wires and nanotubes
Authors: Feng ShiQuan , Wu Weidong , Cheng Xinlu
Published: January 2011

In the present paper, the interaction between C3 molecular wires and nanotubes is studied by using first‐principles calculations based on spin density functional theory. We optimize the geometries structures of isolated C3 molecules. In addition, we present the bond lengths and bond angles for the C3 molecular wires that are inserted into different single‐walled carbon nanotubes (SWCNTs). In addition, the binding energies between C3 and SWCNTs are also calculated. Furthermore, the energy band structures and electron density of states (DOS) of C3@(4,4) and C3@(7,0) are also shown and compared with those of armchair SWCNT (4,4) and zigzag SWCNT (7,0). Then, we further investigate the interaction between C3 molecular wires and single‐walled boron nitride nanotubes (SWBNNTs) by the same method used in SWCNTs, and find that the presence of C3 molecules in BNNTs introduces an intermediate band (IB) consisting of two new energy bands. And the IB dramatically decreases the bandgaps of BNNTs.
Identification of shallow Al donors in ZnO
Authors: Herklotz F. , Lavrov E. V. , Weber J. , Mamin G. V. , Kutin Y. S. , Volodin M. A. , Orlinskii S. B.
Published: January 2011

A combined magnetic resonance, photoluminescence, photoconductivity, and Raman scattering study of ZnO is presented. Electron paramagnetic resonance (EPR) and electron‐nuclear double resonance (ENDOR) spectroscopy identify substitutional Al as a binding core of a shallow, effective‐mass‐like donor in ZnO. Based on the correlation between the EPR and photoluminescence data it is shown that recombination of an exciton bound to Al gives rise to the 3360.7 meV photoluminescence line (I6). A$1{\rm s}\to 2{\rm p}$donor transition at 316 cm−1is detected in photoconductivity and Raman spectra.
Ultraviolet luminescence in AlN
Authors: Schulz T. , Albrecht M. , Irmscher K. , Hartmann C. , Wollweber J. , Fornari R.
Published: January 2011

The defect related luminescence in the near UV region between 3 and 4 eV has been investigated in insulating, n‐type and irradiation damaged AlN. A single luminescence band around 3.3 eV with a full width at half maximum of more than 500 meV, is attributed to a donor–acceptor pair transition at low temperatures. The substantial linewidth and a Stokes shift of around 1.3 eV result from strong electron–phonon coupling of the deep acceptor. While the chemical nature of the donor remains ambiguous, the acceptor species is attributed to the isolated Al vacancy, i.e. ${\rm V}_{{\rm Al}}^{{\rm 3}{-} } $. This luminescence band might be interesting for studying n‐type compensation mechanisms in AlN.
Investigation of the confinement potential within GaNAs/GaAs multiple quantum wells
Authors: Goshima Keishiro , Kittaka Akinobu , Fujii Kensuke , Shiraga Masahiro , Tsurumachi Noriaki , Nakanishi Shunsuke , Akiyama Hidefumi , Koshiba Shyun , Itoh Hiroshi
Published: January 2011

We conducted a detailed investigation of the potential structure within GaNAs/GaAs multiple quantum wells (MQWs) using three independent experimental techniques: the temperature dependence of Photo‐luminescence (PL) spectroscopy, time‐resolved PL spectroscopy, and degenerate four‐wave mixing (DFWM) measurements. We observed a very long lifetime (T1 = 12 ns) and dephasing time (T2 = 130 ps) of excitons in the GaNAs/GaAs MQWs. We suggested that the GaNAs/GaAs MQWs have a strong and deep confinement structure that is comparable to that of quantum dots (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental study on elasto‐optic effect in bulk GaN crystal
Authors: Fukuzawa Masayuki , Kashiwagi Ryo , Yamada Masayoshi
Published: January 2011

Elasto‐optic effect has been studied experimentally in bulk α‐GaN crystal. By using an imaging type transmission polariscope, two‐dimensional distribution of refractive index difference |Δn | was measured in the c‐plane of beam‐like samples (3×3×10 mm3) while applying the external stress compressive to its longitudinal directions. The two‐dimensional distribution of |Δn | revealed its local fluctuation reflecting residual strain distribution of the sample because there is no natural birefringence in c‐plane. At the initial stage of stress impression, the |Δn | was increased or decreased at each point according to whether the residual strain is compressive or tensile along the stress‐applied direction. The |Δn | was finally increased with a similar slope at the final stress‐impression stage, regardless of the residual strain level. The |p11‐p12| was obtained as 0.13 from the averaged slope of the final stress‐impression stage, which is useful for estimating the magnitude of residual strain in c‐plane GaN substrates. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AFM‐based photocurrent imaging of epitaxial and colloidal QDs
Authors: Madl M. , Brezna W. , Strasser G. , Klang P. , Andrews A. M. , Bodnarchuk M. I. , Kovalenko M. V. , Yarema M. , Heiss W. , Smoliner J.
Published: January 2011

We present photocurrent images and spectroscopic results of sub‐surface InAs quantum dots (QDs) and thin films of colloidal PbS QDs obtained at room temperature and under ambient conditions by means of photoconductive atomic force microscopy (pcAFM) under 916 nm and 900 nm illumination respectively.

InAs QDs appear as dark areas in the photocurrent image, because imaging was performed at the wetting layer excitation energy. The PbS nanocrystal film imaged at the energy of the first excitonic transition displays local variations of the photoactivity. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study on fabrication method of forming‐free resistance random access memory
Authors: Yoda Takatoshi , Kinoshia Kentaro , Makino Tatsuya , Dobashi Kazufumi , Kishida Satoru
Published: January 2011

In general, the resistance change effect in transition metal oxides appears after a forming process, which is similar to the soft breakdown. However, there exist resistive random access memory cells which do not need the forming process. These cells are initially in the low resistance state and start with a reset process, which is a switching from a low resistance state to a high resistance state. Therefore, filaments are considered to be formed already in an initial state and, therefore, we call this kind of filaments “native filaments (NFIs)”. The first I ‐V characteristics of pristine memory cells with the Pt/NiO/Pt structure, which were formed by using reactive ion etching (RIE), were measured as functions of cell area, S, and NiO thickness, t. As a result, it was shown that the number of NFIs increased with increasing S and with decreasing t. In addition, it was suggested that NFIs exist at the fringe area of the memory cell. These results suggested that an NFI consists of oxygen vacancies which connect top and bottom electrodes, and that vacancies are introduced during the RIE process of the top electrode and the NiO memory layer. Universal relation between a reset current, Ireset, and a total resistance of all NFIs contained in one memory cell was found, providing us a guiding principle to reduce the value and variation of Ireset. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First application of mass spectrometry and gas chromatography in investigation of α‐cellulose hydrolysates: the influence of climate changes on glucose molecules in pine tree‐rings
Authors: Sensuła Barbara M. , Pazdur Anna , Marais Marie‐France
Published: January 2011

We present the first results of the quantitative and qualitative gas chromatographic and isotope ratio mass spectrometric analysis of monosaccharides derived from acid hydrolysis of α‐cellulose extracted from annual pine tree‐rings. The conifers investigated in this study grew in the Niepolomice Forest in Poland, and the annual rings covered the time span from 1940 to 2000 AD. The main components of the α‐cellulose samples were two saccharides: glucose and mannose. The amount of glucose in the annual rings varied between 17 and 44%. The δ13C of glucose was found to be less negative than that of α‐cellulose and the δ18O values in glucose were less positive than those in α–cellulose. The content of monosaccharides in the α‐cellulose samples has an influence on the isotope fractionation factors. The values of the carbon isotope fractionation factor increase with an increase in the monosaccharides concentration in α‐cellulose, while the values of the oxygen isotope fractionation factor decrease with an increase in monosaccharides concentration in α‐cellulose. The challenge is to establish, with respect to climate changes and environmental conditions, the significance of the interannual variations in the observed monosaccharide concentration. Copyright © 2011 John Wiley & Sons, Ltd.
Ets2 Regulates Colonic Stem Cells and Sensitivity to Tumorigenesis
Authors: Múnera Jorge , Ceceña Grace , Jedlicka Paul , Wankell Miriam , Oshima Robert G.
Published: January 2011

Ets2 has both tumor repressive and supportive functions for different types of cancer. We have investigated the role of Ets2 within intestinal epithelial cells in postnatal mouse colon development and tumorigenesis. Conditional inactivation of Ets2 within intestinal epithelial cells results in over representation of Ets2-deficient colon crypts within young and adult animals. This preferential representation is associated with an increased number of proliferative cells within the stem cell region and an increased rate of crypt fission in young mice that result in larger patches of Ets2-deficient crypts. These effects are consistent with a selective advantage of Ets2-deficient intestinal stem cells in colonizing colonic crypts and driving crypt fission. Ets2-deficient colon crypts have an increased mucosal thickness, an increased number of goblet cells, and an increased density. Mice with Ets2-deficient intestinal cells develop more colon tumors in response to treatment with azoxymethane and dextran sulfate sodium. The selective population of colon crypts, the altered differentiation state and increased sensitivity to carcinogen-induced tumors all indicate that Ets2 deficiency alters colon stem cell number or behavior. Ets2-dependent, epithelial cell-autonomous repression of intestinal tumors may contribute to protection from colon cancer of persons with increased dosage of chromosome 21.
Optimal damper placement in steel frames by the Endurance Time method
Authors: Estekanchi Homayoon E. , Basim Mohammad Ch.
Published: January 2011

Performance‐based optimal seismic design of structures requires repetitive and massive dynamic analyses. In the Endurance Time (ET) method, structures are subjected to specially designed intensifying acceleration functions and their response at various excitation levels is estimated by each single response‐history analysis, thus, significantly reducing the required computational demand. In this paper, the ET method is utilized to acquire optimal placement of viscous dampers in short steel frames with the target of obtaining the desirable performance in two hazard levels simultaneously. In the optimization procedure, the damping coefficients of the added dampers are treated as design variables and assigned such that the total damping coefficients used in the structure would be minimal. Moreover, the performance of the structures before and after damper placement has been evaluated using ground motions. The sensitivity of the results to the selection of a particular set of ground motions is also investigated. Nonlinear models of steel frames have been investigated and the optimization procedures are conducted with genetic algorithm. Recommendations of ASCE/SEI 41‐06 code are followed in setting the performance design criteria. Copyright © 2011 John Wiley & Sons, Ltd.
Maternal cardiac function in complicated twin pregnancy: a longitudinal study
Authors: Ghi T. , Kuleva M. , Youssef A. , Maroni E. , Nanni M. , Pilu G. , Rizzo N. , Pelusi G.
Published: January 2011

Objective

To evaluate longitudinally a cohort of twin pregnancies and to assess whether the occurrence of adverse pregnancy outcome may be related to specific maternal cardiac findings.

Methods

Women with twin pregnancies were enrolled prospectively and underwent serial maternal echocardiography at 20–23 weeks, 26–29 weeks and 30–33 weeks of gestation. Patients were excluded if delivery took place prior to 34 weeks. Cardiac findings were compared between patients with uneventful pregnancy outcome and those who developed one of the following complications: pre‐eclampsia or gestational hypertension; small‐for‐gestational age (SGA) neonates (birth weight of one or both twins < 5th centile for gestational age).

Results

A group of 28 twin gestations was obtained for analysis, including eight complicated cases. At each visit, mean ± SD cardiac output (CO) was significantly higher in uncomplicated than complicated twin pregnancies (6.55 ± 0.82 vs 4.99 ± 0.67 L/min, P < 0.001 at 20–23 weeks; 7.31 ± 0.74 vs 5.66 ± 1.17 L/min, P < 0.001 at 26–29 weeks; 7.50 ± 0.89 vs 5.32 ± 0.74 L/min, P < 0.001 at 30–33 weeks), as was stroke volume (83.4 ± 12.2 vs 64.5 ± 9.2 mL, P = 0.001 at 20–23 weeks; 84.4 ± 15.6 vs 64.5 ± 12.0 mL, P = 0.003 at 26–29 weeks; 85.0 ± 19.2 vs 65.6 ± 10.7 mL, P = 0.013 at 30–33 weeks), whereas total vascular resistance (TVR) was lower (1005 ± 137 vs 1406 ± 159 dynes × s/cm5, P < 0.001 at 20–23 weeks; 924 ± 100 vs 1249 ± 231 dynes × s/cm5, P < 0.001 at 26–29 weeks; 929 ± 96 vs 1400 ± 244 dynes × s/cm5, P < 0.001 at 30–33 weeks). Moreover, CO, blood pressure (BP), heart rate (HR) and TVR remained stable throughout the assessed pregnancy interval in women developing a complication, whereas significant changes (rise in CO, HR and BP; fall in TVR) were noted in the uncomplicated group.

Conclusions

Maternal cardiac function in twin pregnancies complicated by pre‐eclampsia or SGA neonates apparently does not undergo the profound longitudinal changes that occur in uneventful twin pregnancies. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Incidence and clinical implications of early inadvertent septostomy after laser therapy for twin–twin transfusion syndrome
Authors: Cruz‐Martinez R. , Van Mieghem T. , Lewi L. , Eixarch E. , Cobo T. , Martinez J. M. , Deprest J. , Gratacos E.
Published: January 2011

Objective

To evaluate the incidence and clinical outcome of inadvertent septostomy after fetoscopic laser therapy for twin–twin transfusion syndrome (TTTS) and, particularly, to explore its association with the risk of developing pseudoamniotic band syndrome (PABS).

Methods

In a cohort of 414 consecutive monochorionic twin pregnancies with confirmed TTTS treated with laser, the incidence of postoperative septostomy within 1 week of the procedure was recorded prospectively. Rates of preterm delivery, preterm premature rupture of membranes (PPROM), intrauterine fetal demise (IUFD) and PABS were compared among cases with and without septostomy.

Results

The mean gestational age at laser therapy was 20.4 (range, 15.3–27.6) weeks. Postoperative septostomy occurred in 30 (7.2%) cases. Pregnancies complicated with septostomy had a significantly higher proportion of preterm delivery before 32 weeks (76.7% vs. 30.2%, P < 0.001), PPROM before 32 weeks (46.7% vs. 19.0%, P < 0.001), IUFD (43.3% vs. 25.8%, P < 0.05) and PABS (13.3% vs. 1.0%, P < 0.001), compared with pregnancies without septostomy.

Conclusions

Inadvertent septostomy occurred in 7% of cases after fetoscopic laser therapy and was associated with a substantially increased risk of adverse perinatal outcome and PABS. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.