bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the polyamine analogue N1,N11‐diethylnorspermine on cell survival and susceptibility to apoptosis of human chondrocytes
Authors: Stanic Ivana , Cetrullo Silvia , Facchini Annalisa , Stefanelli Claudio , Borzì Rosa Maria , Tantini Benedetta , Guarnieri Carlo , Caldarera Claudio Marcello , Flamigni Flavio
Published: January 2008

Chondrocyte survival is closely linked to cartilage integrity, and forms of chondrocyte apoptotic death can contribute to cartilage degeneration in articular diseases. Since growing evidence also implicates polyamines in the control of cell death, we have been investigating the role of polyamine metabolism in chondrocyte survival and apoptosis. Treatment of human C‐28/I2 chondrocytes with N1,N11‐diethylnorspermine (DENSPM), a polyamine analogue with clinical relevance as an experimental anticancer agent, inhibited polyamine biosynthesis and induced polyamine catabolism, thus rapidly depleting all main polyamines. DENSPM did not increase significantly caspase activity, but provoked a late cell death associated to DNA fragmentation. A short treatment with DENSPM did not reduce cell viability when given alone, but enhanced caspase‐3 and ‐9 activation in chondrocytes exposed to tumor necrosis factor‐α (TNF) and cycloheximide (CHX). A longer treatment with DENSPM however reduced caspase response to TNF plus CHX. Depletion of all polyamines obtained by specific inhibitors of polyamine biosynthesis did not cause cell death and contrasted apoptosis by decreasing caspase activities. In conclusion, following DENSPM treatment, C‐28/I2 chondrocytes are initially sensitized to caspase 9‐dependent apoptosis in the presence of TNF and CHX and may eventually undergo a late and mainly caspase‐independent cell death in the absence of other stimuli. Moreover, these results indicate that a reduction of polyamine levels not only leads to inhibition of cell proliferation, but also of caspase‐mediated pathways of chondrocyte apoptosis. J. Cell. Physiol. 216: 153–161, 2008. © 2008 Wiley‐Liss, Inc.
The electronic delocalization in para‐substituted β‐nitrostyrenes probed by resonance Raman spectroscopy and quantum‐chemical calculations
Authors: Ando Rômulo A. , Cunha Rodrigo L. O. R. , Juliano Luiz , Borin Antonio C. , Santos Paulo S.
Published: January 2008

The electronic (UV‐vis) and resonance Raman (RR) spectra of a series of para‐substituted trans‐β‐nitrostyrenes were investigated to determine the influence of the electron donating properties of the substituent (X = H, NO2, COOH, Cl, OCH3, OH, N(CH3)2, and O−) on the extent of the charge transfer to the electron‐withdrawing NO2 group directly linked to the ethylenic (C = C) unit. The Raman spectra and quantum chemical calculations show clearly the correlation of the electron donating power of the X group with the wavenumbers of the νs(NO2) and ν (C = C)sty normal modes. In conditions of resonance with the lowest excited electronic state, one observes for X = OH and N(CH3)2 that the symmetric stretching of the NO2, νs(NO2), is the most substantially enhanced mode, whereas for X = O−, the chromophore is extended over the whole molecule, with substantial enhancement of several carbon backbone modes. Copyright © 2008 John Wiley & Sons, Ltd.
Micro‐Raman spectroscopy on analcime and pollucite in comparison to X‐ray diffraction
Authors: Presser V. , Kloužková A. , Mrázová M. , Kohoutková M. , Berthold C.
Published: January 2008

Natural and synthetic samples of analcime and pollucite (both zeolites belonging to the analcime group) were studied by means of micro‐Raman spectrometry, X‐ray fluorescence analysis (XFA) and X‐ray diffraction (XRD). On knowing the chemical and structural characteristics of each solid‐solution member, the observed shift in the spectral position of the Raman active modes can be explained and used for phase determination. As shown, the distinction between members of the analcime–pollucite solid‐solution series using Raman spectroscopy is significantly more conclusive than the corresponding XRD findings. Also, information about the structurally bound water inside the zeolite structure can be gained using Raman spectroscopy as long as a suitable exciting wavelength is selected. Copyright © 2008 John Wiley & Sons, Ltd.
Functional biscuits with PUFA‐ω3 from Isochrysis galbana
Authors: Gouveia Luísa , Coutinho Carla , Mendonça Emanuel , Batista Ana Paula , Sousa Isabel , Bandarra Narcisa M , Raymundo Anabela
Published: January 2008

BACKGROUND: Sweet biscuits, a traditional and nutritious food, can be healthy and very attractive when redesigned to be prepared with the addition of a natural product, the microalgal biomass of Isochrysis galbana. This marine microalga is recognised as a rich source of polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA; 20:5ω3), and is a promising ingredient in the food and feed industries. The importance of PUFA‐ω3 (an alternative to fish oils) in food, and the need to increase the daily intake of these substances to promote a healthier lifestyle is now well known.

RESULTS: Traditional butter biscuits were enriched with I. galbana biomass (1% and 3%) and evaluated in terms of colour, texture and fatty acid profile, within 3 months of storage. I. galbana biscuits presented total levels of 100 mg 100 g−1 and 320 mg 100 g−1 of PUFA‐ω3 (EPA + DPA (docosapentaenoic acid; 22:5ω3) + DHA (docosahexaenoic acid; 22:6ω3) for 1% and 3% I. galbana, respectively.

CONCLUSION: The enhancement of texture properties, the high stability of colour and texture and the good profile of polyunsaturated fatty acids, with emphasis on EPA and DHA, of the biscuits obtained, reveal a new food market niche opportunity. Copyright © 2008 Society of Chemical Industry
Reconstructive microsurgery in pediatric population—A series of 25 patients
Authors: Yildirim Serkan , Calikapan Gaye Taylan , Akoz Tayfun
Published: January 2008

Pediatric microsurgery procedures possess various difficulties when compared with adults. However, both free tissue transfers and replantation of the amputated parts show remarkable success rates in children. The concerns of survival of the flaps and the amputated parts have shifted to the function of these in the adulthood. Several key points and hints allow successfull rates for both survival and function. We present a series of microsurgical procedures both free tissue transfers (12 patients) and digital replantations (13 patients). Free tissue transfers included toe‐to‐hand transfers in 5, latsissimus dorsi flaps in 4, fibular flaps in 4, and anterolateral thigh flaps in 2 patients. Thirteen patients involved 17 digital replantations. The survival rate was less in the replantation group (58.75%) than in the free tissue transfer group (93%). Both the functional and the cosmetic results were promising. The follow‐up period was between 1 and 6 years (mean 37 months) for the free tissue transfer group and 1–5 years (mean 20 months) for the replantation group. The major technical difficulties include the age group of 0–2 years. Aside from these the high capacity of regeneration and the improved learning capacity increase the feasibility of the microsurgical procedures proceeded among children. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Primary posterior capsulorhexis with anterior vitrectomy in preventing posterior capsule opacification in pediatric cataract microsurgery
Authors: Luo Yi , Lu Yi , Lu Guosheng , Wang Man
Published: January 2008

Our study was performed to investigate the operative effects of pediatric cataract surgery with anterior vitrectomy. The study comprised of 38 pediatric patients aged 2–5 years and involved a total of 60 eyes with congenital cataracts. The study was done between March 2004 and December 2005. Posterior capsulorhexis with anterior vitrectomy was performed on 34 eyes of 20 children, and cataract extraction was performed on 26 eyes of 18 children. The percentages of various complications and rate of neodymium YAG (Nd:YAG) laser capsulotomy were followed up for 12–36 months. There were significant differences in the percentages of posterior capsule opacification (PCO) and rate of neodymium YAG (Nd:YAG) capsulotomy between the anterior vitrectomy group and cataract extraction group (P < 0.01). The anterior vitrectomy group was associated with less posterior capsular opacification (11.8%) than the cataract extraction group (76.9%). The YAG capsulotomy rate was 2.9% for the anterior vitrectomy group, and 57.7% for the cataract extraction group. After operation the fibrous exudates in anterior chamber and the intraocular lens subluxation or capture were 5.9% and 2.9% for the anterior vitrectomy group while for the cataract extraction group they were 23.1% and 15.4%; the difference was statistically significant (P < 0.05). The results suggest that primary posterior capsulorhexis with anterior vitrectomy in pediatric cataract surgery who are between 2 and 5 years old is necessary and effective procedure with low PCO rate. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Local B1+ shimming for prostate imaging with transceiver arrays at 7T based on subject‐dependent transmit phase measurements
Authors: Metzger Gregory J. , Snyder Carl , Akgun Can , Vaughan Tommy , Ugurbil Kamil , Van de Moortele Pierre‐Francois
Published: January 2008

High‐quality prostate images were obtained with transceiver arrays at 7T after performing subject‐dependent local transmit B1 (B1+) shimming to minimize B1+ losses resulting from destructive interferences. B1+ shimming was performed by altering the input phase of individual RF channels based on relative B1+ phase maps rapidly obtained in vivo for each channel of an eight‐element stripline coil. The relative transmit phases needed to maximize B1+ coherence within a limited region around the prostate greatly differed from those dictated by coil geometry and were highly subject‐dependent. A set of transmit phases determined by B1+ shimming provided a gain in transmit efficiency of 4.2 ± 2.7 in the prostate when compared to the standard transmit phases determined by coil geometry. This increased efficiency resulted in large reductions in required RF power for a given flip angle in the prostate which, when accounted for in modeling studies, resulted in significant reductions of local specific absorption rates. Additionally, B1+ shimming decreased B1+ nonuniformity within the prostate from (24 ± 9%) to (5 ± 4%). This study demonstrates the tremendous impact of fast local B1+ phase shimming on ultrahigh magnetic field body imaging. Magn Reson Med 59:396–409, 2008. © 2008 Wiley‐Liss, Inc.
Compressed sensing in dynamic MRI
Authors: Gamper Urs , Boesiger Peter , Kozerke Sebastian
Published: January 2008

Recent theoretical advances in the field of compressive sampling—also referred to as compressed sensing (CS)—hold considerable promise for practical applications in MRI, but the fundamental condition of sparsity required in the CS framework is usually not fulfilled in MR images. However, in dynamic imaging, data sparsity can readily be introduced by applying the Fourier transformation along the temporal dimension assuming that only parts of the field‐of‐view (FOV) change at a high temporal rate while other parts remain stationary or change slowly. The second condition for CS, random sampling, can easily be realized by randomly skipping phase‐encoding lines in each dynamic frame. In this work, the feasibility of the CS framework for accelerated dynamic MRI is assessed. Simulated datasets are used to compare the reconstruction results for different reduction factors, noise, and sparsity levels. In vivo cardiac cine data and Fourier‐encoded velocity data of the carotid artery are used to test the reconstruction performance relative to k‐t broad‐use linear acquisition speed‐up technique (k‐t BLAST) reconstructions. Given sufficient data sparsity and base signal‐to‐noise ratio (SNR), CS is demonstrated to result in improved temporal fidelity compared to k‐t BLAST reconstructions for the example data sets used in this work. Magn Reson Med 59:365–373, 2008. © 2008 Wiley‐Liss, Inc.
Quantitative magnetic resonance of postmortem multiple sclerosis brain before and after fixation
Authors: Schmierer Klaus , Wheeler‐Kingshott Claudia A.M. , Tozer Daniel J. , Boulby Phil A. , Parkes Harold G. , Yousry Tarek A. , Scaravilli Francesco , Barker Gareth J. , Tofts Paul S. , Miller David H.
Published: January 2008

Unfixed and fixed postmortem multiple sclerosis (MS) brain is being used to probe pathology underlying quantitative MR (qMR) changes. Effects of fixation on qMR indices in MS brain are unknown. In 15 postmortem MS brain slices T1, T2, MT ratio (MTR), macromolecular proton fraction (fB), fractional anisotropy (FA), and mean, axial, and radial diffusivity (MD, Dax, and Drad) were assessed in white matter (WM) lesions (WML) and normal appearing WM (NAWM) before and after fixation in formalin. Myelin content, axonal count, and gliosis were quantified histologically. Student's t‐test and regression were used for analysis. T1, T2, MTR, and fB obtained in unfixed MS brain were similar to published values obtained in patients with MS in vivo. Following fixation T1, T2 (NAWM, WML) and MTR (NAWM) dropped, whereas fB (NAWM, WML) increased. Compared to published in vivo data all diffusivity measures were lower in unfixed MS brain, and dropped further following fixation (except for FA). MTR was the best predictor of Tmyelin (inversely related to myelin) in unfixed MS brain (r = −0.83; P < 0.01) whereas postfixation T2 (r = 0.92; P < 0.01), T1 (r = 0.89; P < 0.01), and fB (r = −0.86; P < 0.01) were superior. All diffusivity measures (except for Dax in unfixed tissue) were predictors of myelin content. Magn Reson Med 59:268–277, 2008. © 2008 Wiley‐Liss, Inc.
Using saliva to measure endogenous cortisol in nursing home residents with advanced dementia
Authors: Woods Diana Lynn , Kovach Christine R. , Raff Hershel , Joosse Laura , Basmadjian Alicia , Hegadoren Kathleen M.
Published: January 2008

Two research teams determined the feasibility of saliva collection for cortisol measurement in nursing home residents with advanced dementia. Study aims were to: (a) determine if sufficient saliva could be obtained for assay and (b) examine whether cortisol values exhibited range and variability for meaningful interpretation. Useable samples were consistent across sites, suggesting that saliva collection for cortisol assay is a viable method in this setting. Cortisol values showed range and variability. More than half of the residents showed the normal adult pattern of high morning levels decreasing throughout the day. A third of the participants demonstrated an increase in the evening cortisol levels, while the remaining profiles were flat, suggesting hypothalamic–pituitary–adrenal (HPA) dysregulation in this population. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:283–294, 2008
Redesigning health information systems in developing countries: the need for local flexibility and distributed control
Authors: Kimaro Honest C. , Mengiste Shegaw A. , Aanestad Margunn
Published: January 2008

Despite widespread aims to strengthen the Health Information System (HIS) as a tool for decentralised health care, there is a strong tendency in most developing countries that the HIS continues to reflect the central level's needs and requirements. The traditional design approach with little or no end user involvement results in a centralised HIS with an extensive, somewhat inappropriate, but also inflexible set of standards. Consequently, the HIS is not very useful for the wished‐for decentralisation of health services, and there is an urgent need to redesign the existing HIS in order to make it locally relevant and appropriately decentralised. Based on a comparative case analysis of the HIS in Tanzania and Ethiopia, we offer practical recommendations on the way to achieve this redesign. A central design goal should be to achieve a balance between centralised control and local autonomy. Some degree of control over a decentralised HIS, including budgets and the use of resources, should be delegated to the district administration. In order to achieve the aim of a locally relevant, well‐working HIS, it is necessary that appropriate authority, capacity and decentralised allocation of resources for HIS will be developed at the district and sub‐district levels. Copyright © 2008 John Wiley & Sons, Ltd.
Bringing psychological science to the forefront of educational policy: Collaborative efforts of the American Psychological Association's Coalition for Psychology in the Schools and Education
Authors: Rollin Stephen A. , Subotnik Rena F. , Bassford Maya , Smulson Jennifer
Published: January 2008

The following article details the work of the American Psychological Association's (APA's) Coalition for Psychology in the Schools and Education (CPSE). First, a brief history of the background and creation of the coalition is described. The article then details the projects, completed and ongoing, of the CPSE. Those projects include a Teacher Needs Survey, the work of the Applications of Psychological Science to Teaching and Learning Task Force, and work in education advocacy and on the Higher Education Act. The article concludes with details regarding the composition of the CPSE and specifics regarding the APA divisions represented. © 2008 Wiley Periodicals, Inc.
Mastery learning and assessment: Implications for students and teachers in an era of high‐stakes testing
Authors: Zimmerman Barry J. , Dibenedetto Maria K.
Published: January 2008

Federal efforts to improve American students' achievement through high‐stakes testing have led to significant concerns about the fairness and effectiveness of standardized tests. We attribute these concerns to the use of summative tests to assess academic progress without the benefits of an effective formative model of assessment and instruction, such as mastery learning. Historically, mastery learning models emerged as a reaction to the misuse of psychometric models of assessment for instructional purposes. Differences between these models are discussed along with a more recent form of mastery assessment, curriculum‐based measurement. Apprehensions about the summative testing requirements of No Child Left Behind are considered along with efforts to make these tests fairer, such as the inclusion of a growth provision. Finally, we identified a mastery learning intervention program in mathematics in a high school that achieved national recognition, and we interviewed participating teachers and students. They reported the positive academic and motivational outcomes expected of a mastery learning approach and a few concerns about drawbacks associated with high‐stakes testing. © 2008 Wiley Periodicals, Inc.
Health locus of control questionnaire for patients with chronic low back pain: psychometric properties of the Brazilian–Portuguese version
Authors: Oliveira Vinícius Cunha , Furiati Thiago , Sakamoto Ana , Ferreira Paulo , Ferreira Manuela , Maher Chris
Published: January 2008

Background and Purpose. Low back pain is common among Brazilians, especially affecting those who are working. Psychosocial factors, such as the health locus of control, are associated with low back pain prognoses. Although the multidimensional health locus of control questionnaire is widely employed in individuals with low back pain, a Brazilian–Portuguese version is not yet available. The aim of the present study was to translate and adapt the multidimensional health locus of control (MHLC) questionnaire, and to investigate its psychometric properties in a Brazilian population with non‐specific chronic low back pain. Method. Translation and adaptation of the questionnaire was carried out in the first phase of the study. In the second phase it was administered to Brazilians with non‐specific chronic low back pain to evaluate its intra‐examiner reliability (n = 20), concurrent validity, internal consistency (n = 40), and floor and ceiling effects. To evaluate concurrent validity the Brazilian–Portuguese version of the Roland–Morris disability questionnaire was used as the comparison. Results. The sub‐scales demonstrated good to excellent reliability with intra‐class coefficient (ICC) values of 0.75 for the external subscale (95% confidence interval (95% CI): 0.46–0.89), 0.87 for the internal sub‐scale (95% CI: 0.69–0.94) and 0.90 for the chance sub‐scale (95% CI: 0.77–0.96). For concurrent validity, the external and chance sub‐scales correlated positively with disability (Pearson's r = 0.58; p < 0.001 and Pearson's r = 0.35; p = 0.025), respectively, while the internal sub‐scale correlated negatively with disability (Pearson's r = −0.33; p = 0.037). The questionnaire had acceptable internal consistency, with a Cronbach's alpha value of 0.65 (95% CI: 0.46–0.80) for external sub‐scale, 0.77 (95% CI: 0.64–0.87) for internal sub‐scale and 0.83 (95% CI: 0.73–0.90) for chance sub‐scale. Conclusions. The Brazilian–Portuguese version of the MHLC questionnaire has acceptable measurement properties similar to that observed with the original English language version. Copyright © 2008 John Wiley & Sons, Ltd.
Single impurity Anderson model and band anti‐crossing in the Ga1–xInx Ny As1–y material system
Authors: Vogiatzis Nikolaos , Rorison Judy M.
Published: January 2008

The role of the single‐N impurity in the GaInNAs system is evaluated using the single impurity Anderson model. The N impurities can act either as scattering resonances or as bound states depending on their energy position. For the former case, using self‐energy calculations and Matsubara Green's functions we investigate the nature of the mixed single‐N state (energy broadening, shift). The effect of this interaction on the perturbed conduction subbands is also examined. The single impurity Anderson model results in a complex band structure. The real part of the band structure can be directly related to the dispersion obtained with the band anti‐crossing model and is in very good agreement. The imaginary bandstructure contains further information about the mixing of the nitrogen state and the conduction band which is not contained within the band anti‐crossing model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Research on inorganic electroluminescence – present status
Authors: Kobayashi H. , Ohmi K. , Ichino K. , Kunimoto T.
Published: January 2008

In this paper, we discuss the present status of electroluminescence (EL) of inorganic materials. From 1970's, the main research was made on multicolor and fullcolor EL. Finally blue inorganic EL of BaAl2S4:Eu was developed, resulting in fullcolor EL‐TV using “color by blue®” by iFire Technology. Very recently, a new ultra bright inorganic EL of dc driven at lower than 10 V has been developed. These three findings will stimulate the researches on inorganic EL, which slowed down and were not active in the past two decades. Some new findings are expected. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence spectra of Eu‐doped GaN
Authors: Sawahata J. , Seo J. W. , Chen S. , Akimoto K.
Published: January 2008

Luminescence spectra of Eu‐doped GaN with varying Eu concentration and V/III ratio were investigated. Eu‐related luminescence originating from the 5D0–7F2 transition of Eu3+ was observed at about 622 nm. The luminescence basically consisted of three peaks, and the relative intensity of the three peaks was affected by the Eu concentration and the V/III ratio. These results indicate that the Eu incorporation site is very sensitive to the Eu concentration and the V/III ratio. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Manganese behaviour in ZnO layers deposited by magnetron sputtering for spintronic application
Authors: Abouzaid M. , Ruterana P. , Liu C. , Morkoç H.
Published: January 2008

In this work, we carry out structural analysis of ferromagnetic Mn‐doped ZnO thin films deposited by radio frequency magnetron sputtering, using transmission electron microscopy (TEM). On top of sapphire (0001) substrates, Mn rich precipitates and an interface reaction layer are observed follow‐ ing the deposition of Zn(Mn)O layers above 500 °C. The crystalline quality of ZnO layers deposited by magnetron sputtering is highly improved at 500 °C as well as the measured ferromagnetic response. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Visible and infrared electroluminescence from an Er‐doped n‐ZnO/p‐Si light emitting diode
Authors: Harako S. , Yokoyama S. , Ide K. , Zhao X. , Komoro S.
Published: January 2008

Er‐doped ZnO/Si hetero‐junctions have been formed by laser ablating an Er‐contained ZnO target onto p‐Si(100) substrates. Light emitting diodes fabricated by using these samples exhibited bright green (536 nm and 556 nm), red (665 nm) and 1.54 µm emissions at room temperature. A light emission at 1180 nm was also observed. These emissions arose from intra‐4f transitions in Er3+ ions that were excited by impact excitation process. A threshold voltage of ∼10 V was achieved for emitting multi colors. Our results show a strong possibility of realizing the Si‐based light emitting devices by Er doing. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rare earth doping of III‐nitride alloys by ion implantation
Authors: Lorenz K. , Alves E. , Roqan I. S. , Martin R. W. , Trager‐Cowan C. , O'Donnell K. P. , Watson I. M.
Published: January 2008

The implantation damage and rare earth (RE) luminescence in the wide band gap ternaries AlGaN and AlInN were studied and compared to GaN. For both ternaries lower damage levels were observed and in contrast to GaN, no surface amorphisation occurs during the implantation. Damage recovery of RE implanted GaN was studied for post implant annealing at temperatures between 800 °C and 1300 °C. The blue and IR Tm related luminescence intensity is seen to increase strongly with the annealing temperature. The two Tm lines observed at 478 nm and 465 nm are assigned to the 1G4 → 3H6 and the 1D2→3F4 transition, respectively. For GaN the line at 465 nm is fully quenched at RT while it becomes the dominant line for the ternaries. The blue luminescence intensity in the ternaries is significantly stronger than in GaN. Furthermore, AlInN shows a very high ratio of blue/IR luminescence. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependent site change of In in AlN and GaN
Authors: Schmitz J. , Penner J. , Lorenz K. , Vianden R.
Published: January 2008

Hyperfine interaction studies by means of the perturbed angular correlation technique have been carried out on In implanted into GaN and AlN. After the implantation of the probe 111In with 160 keV and annealing of the radiation damage for 120 s at 1273 K, it is found, that in both materials 50–60% of the In probes occupy regular lattice sites at room temperature. The remaining second fraction is found in a quite different but relatively well defined lattice environment. The regular fraction increases at the cost of the second fraction to approx. 100% at a sample temperature of 600 K in GaN and 900 K in AlN. The effect is completely reversible, i.e. the fractions change back to their previous values if the sample is measured again at room temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaInNAs(Sb) surface normal devices
Authors: Calvez S. , Laurand N. , Sun H. D. , Weda J. , Burns D. , Dawson M. D. , Harkonen A. , Jouhti T. , Pessa M. , Hopkinson M. , Poitras D. , Gupta J. A. , Leburn C. G. , Brown C. T. A. , Sibbett W.
Published: January 2008

After a decade of intensive research on GaInNAs(Sb) on GaAs alloys, this paper summarizes some of the key properties of these III–V alloys and presents current progress in their exploitation in a variety of surface‐normal operating devices such as Vertical (External)‐Cavity Surface‐Emitting Lasers (V(E)CSELs) and SEmiconductor Saturable Absorber Mirrors (SESAMs). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: phys. stat. sol. (a) 205/1
Authors: Kimura Tadamasa
Published: January 2008

This issue of physica status solidi (pps) contains contributed papers based on the invited talks at the 2nd Workshop on “Impurity Based Electroluminescent Devices and Materials” (IBEDM 2006) held in Nanki‐Shirahama, Wakayama, Japan, on 17–20 October 2006. The 1st Workshop “Impurity Based Electroluminescence in Wide Bandgap Semiconductors” was held in Santa Fe, New Mexico, USA, in April 2003 and was hosted by Dr. John Zavada, U.S. Army Research Office, and Prof. Andrew Steckl, University of Cincinnati. About 40 people from USA, Europe and Japan participated in the 1st Workshop and many useful and pleasant discussions took place. Owing to the success of the Santa Fe Workshop, the organizers came to an agreement to hold the 2nd Workshop in Japan in order to give greater opportunity for scientists in Asia to attend.

The scope of IBEDM 2006 included various types of impurity based electroluminescent devices fabricated from semiconductors, oxides, inorganic and organic materials, as well as novel materials such as nano‐particles and nano‐wires. The following topics were covered at the workshop:

1. Growth and structural properties of rare earth doped materials (semiconductors, oxides, organic materials).

2. Basic optical properties of rare earth doped semiconductors.

3. Optical processes of excitation and energy transfer in impurity doped materials.

4. Luminescence of nano‐particles and nano‐wires doped with rare earth elements.

5. Device structures: Schottky, impact excitation, e‐h recombination.

6. Full color electroluminescent materials and devices.

7. Novel inorganic and organic luminescent materials and devices.

8. Phosphor materials for full color and white color displays.

We had 36 participants (US/Mexico, Europe, Asia/Japan), and 25 valuable presentations (all invited talks) by the top researchers from the world in this field. We had also two evening sessions, where hot topic discussions on impurity based silicon and widegap semiconductors lasted until late at night. All the participants stayed in the same hotel and spent four days together. We think that the concentrated discussions were very fruitful and gave the participants exciting new insights into the understanding of the luminescent devices and materials based on impurities.

The papers contributed to this special issue of pss are based on the presentations and discussions given at IBEDM 2006. Before closing the Workshop, we came to an agreement that this Workshop was very valuable and that a 3rd Workshop should take place in near future. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Disorder effects in GaAs/InxGa1–xAs/GaAs quantum well delta doped with Mn
Authors: Aronzon B. , Lagutin A. , Rylkov V. , Pankov M. , Lashkul A. , Laiho R.
Published: January 2008

We present results of magnetic and transport measurements of GaAs/Ga1–xInxAs/GaAs quantum well structures containing a Mn δ‐layer separated from the quantum well by a 3 nm spacer. The kink observed in temperature dependence of the sample resistance and anomalous Hall effect give a hint for carrier spin polarization. Magnetization measurements show an unusual shifted hysteresis loop. The observed results are treated in the frame of long range fluctuation potential model. Parameters of the potential are estimated. It is shown that disorder determines the structural properties in spite of the hole mobility of about 2000 cm2/(V·s) being much higher than in presently known ferromagnetic two‐dimensional structures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Current‐driven switching of a small‐polaron semiconductor to a meta‐stable conductor
Authors: Emin D.
Published: January 2008

Many materials with low‐mobility charge carriers manifest current‐driven electronic switching between low‐conductivity and high‐conductivity transport. Available measurements suggest that the low‐conductivity carriers of these switches form small polarons. Here a mechanism is described via which driving a sufficiently high current through a material whose carriers form small polarons destabilizes them with respect to forming free carriers. The electrical conductivity then rises sharply since a free‐carrier's mobility is many orders of magnitude higher than that of a small polaron. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of hopping‐edge in amorphous hydrogenated silicon
Authors: Murayama Kazuro , Hoshino Takuya , Ogiwara Chisato
Published: January 2008

Luminescence peak energy of amorphous hydrogenated silicon (a‐Si:H) increases with excitation energy in the Urbach tail and in the higher excitation energy range the peak energy is constant. The excitation energy at which the peak energy turns from increase to constant is shown to be understood as the hopping‐gap. The hopping‐gap decreases with temperature as in the case of the optical bandgap. Furthermore, it is discussed by comparing with the luminescence in porous Si that the luminescence in a‐Si:H may be due to the radiative recombination of electron‐hole pairs in hydrogen‐free Si nanostructures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Current challenges for FDA‐regulated bioanalytical laboratories for human (BA/BE) studies, Part II: recent FDA Inspection trends for bioanalytical laboratories using LC/MS/MS methods and FDA Inspection readiness preparation
Authors: Chow Frank , Lum Steven , Ocampo Arlene , Vogel Paul
Published: January 2008

This article is the second of a three‐part series that deals with the recent Food and Drug Administration (FDA) inspectional trends for bioanalytical laboratories performing analysis for human bioavailability (BA)/bioequivalence (BE) studies. While the FDA compliance expectations have been published in various FDA guidances, as well as the Compliance Program Guidance Manual for current Good Manufacturing Practice and Good Laboratory Practice (as discussed in Part 1 of this series), there are no specific regulations that mandate the operation and control of the bioanalytical laboratories conducting analyses for human BA/BE studies. It is apparent that the compliance standards and analytical testing requirements have been subject to a dynamically evolving process, slowly developed through several workshops jointly sponsored by the FDA and the pharmaceutical industry in the past decade. As the FDA expectations in the practices of bioanalytical laboratories become clearer, an increased trend is observed for the number of FDA 483 observations and untitled letters issued. This article provides a detailed analysis of the current FDA guidance and apparent expectations based on inspectional trends observed. In addition, the compliance and scientific basis of these dynamically evolving regulatory issues are also discussed, where applicable. Copyright © 2008 John Wiley & Sons, Ltd.
Better medicines for children: clinical investigation of medicinal products in the paediatric population ‐ a QA perspective
Authors: Fortwengel Gerhard , Ostermann Herwig , Staudinger Roland
Published: January 2008

Currently the number of medicinal products labelled for paediatric use is limited. Clinical trials involving children are surely amongst the most challenging types of studies performed from a scientific, ethical and medical perspective. The article provides an outline of critical issues to be considered when developing drugs in this population. Copyright © 2008 John Wiley & Sons, Ltd.
What's New?
Authors: Bens Catherine M. , Clemons Stephanie
Published: January 2008

The What's New? section in the Quality Assurance Journal aims to draw attention to items of importance to QA professionals. There is usually a three‐month interval between final submission of manuscripts and distribution of the journal. For this issue, the entries in the What's New? section arise from the period of 1 December 2006 to 28 February 2007. If you feel that there is any other new information that should be brought to the attention of readers, please let us know by e‐mailing rha@verdandi.ch. Copyright © 2008 John Wiley & Sons, Ltd.
Amino‐group‐specific natural abundance nitrogen isotope ratio analysis in amino acids
Authors: Zhang Lin , Altabet Mark A.
Published: January 2008

Amino acid (AA) nitrogen (N) stable isotope ratio analysis has found a wide variety of important applications including indication of the trophic level of an organism, tracing N transfer within food webs, and monitoring of AA resynthesis during heterotrophic microbial reworking of organic matter. Despite its utility, the current methodology is difficult to employ consistently for natural abundance level precision. Here, we report a new and robust method for high‐precision N‐compound‐specific isotope analysis (N‐PCIA) for single‐N‐containing AAs and N‐position‐specific isotope analysis (N‐PSIA) for poly‐N AAs. First the amino‐N in AAs was liberated and oxidized to NO by hypochlorite at high pH. The NO produced was then quantified colorimetrically with excess hypochlorite quenched using arsenite. Subsequently, buffered azide was used to reduce NO to N2O for isotope ratio analysis using a purge‐and‐trap isotope ratio mass spectrometer. In the case of glycine δ15N, the average precision was SD = 0.3‰. Reaction yields and labeling experiments show that this oxidation reaction is highly specific, targeting the α‐amino group (peptide‐N) of most poly‐N AAs. This permits specific determination of the δ15N of peptide‐N in arginine, tryptophan, and histidine. In the case of lysine, however, the side‐chain amino group was found to be partially labile to hypochlorite oxidation. Using isotope fractionation factors estimated from single‐N analogues of lysine, the intramolecular δ15N of lysine was calculated by mass balance, and this generally agreed with results for the same sample material analyzed by a previously published enzymatic method. Our method has the advantages of being relatively rapid, robust, and applicable to all poly‐N AAs. We have also found it to work well for determining total δ15N of amino‐N in complex sample matrices that have not been susceptible to previous approaches. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of resource allocation policies for reducing project durations: a systems modelling approach
Authors: Lee Zee Woon , Ford David N. , Joglekar Nitin
Published: January 2008

Minimizing duration is critical to success in many development projects. Resource allocation policies during such projects determine the fractions of resources that are to be assigned to constituent tasks. The choice of allocation policy can strongly influence project durations. But policies for reduced project duration are difficult to design and implement because of closed loop flows of work that generate dynamic demand patterns and delays in shifting resources among activities. Resource demand estimates and resource adjustment times are two policy features that managers can readily alter to influence project durations. These features are used to describe allocation policies in a relatively simple project model. Myopic and foresighted policies are distinguished by their use (or lack thereof) of rework and multiple backlogs in allocation. Optimal policies under perfect and limited managerial control are described by testing myopic and foresighted policies across a range of project complexities and adjustment times under deterministic and uncertain conditions. Counter‐intuitive results from this analysis indicate that minimum resource allocation delay does not produce minimum durations, and increasing uncertainty decreases durations under certain conditions. The model is used to explain these results. Managerial implications and future research topics are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Evaluation of Protocol Uniformity Concerning Laparoscopic Cholecystectomy in The Netherlands
Authors: Wauben Linda S. G. L. , Goossens Richard H. M. , van Eijk Daan J. , Lange Johan F.
Published: January 2008

Background

Iatrogenic bile duct injury remains a current complication of laparoscopic cholecystectomy. One uniform and standardized protocol, based on the “critical view of safety” concept of Strasberg, should reduce the incidence of this complication. Furthermore, owing to the rapid development of minimally invasive surgery, technicians are becoming more frequently involved. To improve communication between the operating team and technicians, standardized actions should also be defined. The aim of this study was to compare existing protocols for laparoscopic cholecystectomy from various Dutch hospitals.

Methods

Fifteen Dutch hospitals were contacted for evaluation of their protocols for laparoscopic cholecystectomy. All evaluated protocols were divided into six steps and were compared accordingly.

Results

In total, 13 hospitals responded—5 academic hospitals, 5 teaching hospitals, 3 community hospitals—of which 10 protocols were usable for comparison. Concerning the trocar positions, only minor differences were found. The concept of “critical view of safety” was represented in just one protocol. Furthermore, the order of clipping and cutting the cystic artery and duct differed. Descriptions of instruments and apparatus were also inconsistent.

Conclusions

Present protocols differ too much to define a universal procedure among surgeons in The Netherlands. The authors propose one (inter)national standardized protocol, including standardized actions. This uniform standardized protocol has to be officially released and recommended by national scientific associations (e.g., the Dutch Society of Surgery) or international societies (e.g., European Association for Endoscopic Surgery and Society of American Gastrointestinal and Endoscopic Surgeons). The aim is to improve patient safety and professional communication, which are necessary for new developments.
The Use of CEEA 34 in Stapled Hemorrhoidectomy: Suggested Modifications in Technique
Authors: Chew M. H. , Tan W. S. , Eu K. W.
Published: January 2008

Stapled hemorrhoidectomy has been shown to be superior to conventional hemorrhoidectomy in numerous randomized, controlled trials and systemic reviews, with less postoperative pain and faster recovery. Premium Plus CEEA 34 has been recently introduced for use in stapled hemorrhoidectomy. The use of this stapler requires some modifications in technique.
Value of a Systematic Operative Protocol for Cocaine Body Packers
Authors: Veyrie Nicolas , Servajean Stéphane , Aissat Abdelhalim , Corigliano Nicola , Angelakov Céline , Bouillot Jean‐Luc
Published: January 2008

Background

Internal concealment of illicit drugs during international drug traffic represents an important problem in developed countries. These drug traffickers are called “body packers.” The aim of this study was to analyze retroprospectively the surgical indications and complications for cocaine body packers and to describe our systematic operative protocol.

Methods

From January 1997 to December 2005, 1,181 cocaine body packers were admitted to our Medico‐Judiciary Emergency Department. All patients had the same medical surveillance protocol. Nineteen patients required surgical procedure to remove drug packets.

Results

Thirteen patients had obstruction or intestinal retention (68%). Suspicion of packet rupture or cocaine intoxication occurred in six patients (32%). Zero to three enterotomies were necessary during laparotomy. No deaths occurred. One pouch abscess required relaparotomy and one wound abscess was treated medically. The median hospital stay was 7 days (range: 5–30 days).

Conclusions

Few cocaine body packers required a laparotomy. Our systematic operative protocol allowed intestinal clearance and caused acceptable morbidity rate.
Infraumbilical Anterior Retroperitoneal Exposure of the Lumbar Spine in 128 Consecutive Patients
Authors: Brewster Luke , Trueger Nathan , Schermer Carol , Ghanayem Alex , Santaniello John
Published: January 2008

Background

Anterior spinal fusion can be approached through a retroperitoneal exposure lessening the risks of intra‐abdominal exploration. The aim of this study is to report the complication rate and risk factors associated with anterior spinal fusion.

Methods

A retrospective review and analysis of 128 consecutive patients undergoing anterior lumbar fusion was performed looking to correlate potential risk factors with known serious complications of this operation such as vein injury, deep vein thrombosis, pulmonary embolism, and death.

Results

The overall complication rate was 15.5%, with 7.75% being considered serious complications. The most common complication was vein injury (5.4%), but no blood transfusions were required. Postoperatively, there was one death (0.8%), one pulmonary embolism, and one intraoperative hypoxic episode of undetermined etiology. Univariate analysis showed that vein injury was associated with increased operative time (p <. 001) and associated with increased blood loss (p =. 02) but not increased length of stay (p =. 13). By multivariate analysis, operative time and length of stay were influenced by the approach of the operation (anterior alone versus anterior and posterior fixation), but not by the presence of vein injury or blood loss.

Conclusions

In this large series of patients undergoing anterior spinal fusion by a dedicated surgical team, there was a single death, and although vein injury was the most frequent serious complication, it did not lead to an increase in operative time or length of stay.
Transverse nonlinear instability for two-dimensional dispersive models
Authors: Rousset F. , Tzvetkov N.
Published: January 2008

We present a method to prove nonlinear instability of solitary waves in dispersive models. Two examples are analyzed: we prove the nonlinear long time instability of the KdV solitary wave (with respect to periodic transverse perturbations) under a KP-I flow and the transverse nonlinear instability of solitary waves for the cubic nonlinear Schrödinger equation.

On présente une méthode pour prouver l'instabilité non-linéaire d'ondes solitaires dans des modèles dispersifs. Deux exemples sont analysés : on prouve l'instabilité de l'onde solitaire de KdV (par rapport à des perturbations transverses périodiques) dans l'équation de KP-I et l'instabilité transverse nonlinéaire des ondes solitaires de l'équation de Schrödinger non-linéaire cubique.
Minimizers of Dirichlet functionals on the $n$-torus and the weak KAM theory
Authors: Wolansky G.
Published: January 2008

Given a probability measure

μ

on the

n

-torus

\mathbb{T}^{n}

and a rotation vector

\boldsymbol{P} \in \mathbb{R}^{n}

, we ask whether there exists a minimizer to the integral

\int _{\mathbb{T}^{n}}|\mathrm{∇}\phi + \boldsymbol{P}|^{2}\:d\mu

. This problem leads, naturally, to a class of elliptic PDE and to an optimal transportation (Monge–Kantorovich) class of problems on the torus. It is also related to higher dimensional Aubry–Mather theory, dealing with invariant sets of periodic Lagrangians, and is known as the “weak-KAM theory”.

Etant donnés une mesure

μ

sur le tore

n

-dimensionnel

\mathbb{T}^{n}

et un vecteur de rotation

\boldsymbol{P} \in \mathbb{R}^{n}

, on étudie la question de l'existence d'un minimiseur pour l'intégrale

\int _{\mathbb{T}^{n}}|\mathrm{∇}\phi + \boldsymbol{P}|^{2}\:d\mu

. Ce problème conduit naturellement à une classe d'équations aux dérivées partielles elliptiques et à une classe de problèmes de transport optimal (Monge–Kantorovich) sur le tore. Il est aussi lié à la théorie d'Aubry–Mather en dimension supérieure, qui traite les ensembles invariants pour des Lagrangiens périodiques, connue sous le nom de théorie KAM faible.
Metrics of constant curvature on a Riemann surface with two corners on the boundary
Authors: Jost Jürgen , Wang Guofang , Zhou Chunqin
Published: January 2008

In this paper we classify all solutions of

\begin{cases}
−\mathrm{\Delta }u = |x|^{2\alpha }e^{u}, & \text{in }\mathbb{R}_{ + }^{2}, \\ \frac{\partial u}{\partial t} = c_{1}|x|^{\alpha }e^{\frac{u}{2}}, & \text{on }\partial \mathbb{R}_{ + }^{2} \cap \{s > 0\}, \\ \frac{\partial u}{\partial t} = c_{2}|x|^{\alpha }e^{\frac{u}{2}}, & \text{on }\partial \mathbb{R}_{ + }^{2} \cap \{s < 0\} \end{cases}

with the finite energy condition

\int \limits_{\mathbb{R}_{ + }^{2}}|x|^{2\alpha }e^{u}\:dx < \infty ,\:\int \limits_{\partial \mathbb{R}_{ + }^{2}}|x|^{\alpha }e^{\frac{u}{2}}\:ds < \infty .

Here

c_{1}

,

c_{2}

are constants and

\alpha > −1

.