bluuebunny/crossref_metadata_2025 huggingface dataset:
Longitudinal linkages between perceived social support and posttraumatic stress symptoms: Sequential roles of social causation and social selection
Authors: Kaniasty Krzysztof , Norris Fran H.
Published: June 2008

The authors examined social causation and social selection explanations for the association between perceptions of social support and psychological distress. Data came from a sample of 557 victims of natural disaster in Mexico. Structural equation modeling analyses indicated that social causation (more social support leading to less posttraumatic stress disorder [PTSD]) explained the support‐to‐distress relationship in the earlier postdisaster phase, 6 to 12 months after the impact. Both causal mechanisms emerged as significant paths in the midpoint of the study (12 and 18 months). Only social selection (more PTSD leading to less social support) accounted for the support‐to‐distress relationship at 18 to 24 months after the event. Interpersonal and social dynamics of disasters may explain why these two contrasting causal mechanisms emerged over time.
Lifetime family violence exposure is associated with current symptoms of eating disorders among both young men and women
Authors: Brady Sonya S.
Published: June 2008

This study examines (a) whether different forms of lifetime family violence exposure are associated with current eating disorder symptoms among young adults, (b) whether current symptoms of depression and anxiety both mediate these links, and (c) whether findings differ by gender. Participants were 319 university students aged 18–20 years (56% male). Independent of gender, both direct victimization by family violence and witnessing family violence were associated with eating disorder symptoms. Symptoms of depression and anxiety partially mediated these associations, and results did not vary by gender. Findings suggest that depression and anxiety may play a role in the development and maintenance of eating disorder symptoms subsequent to repeated incidents of family violence exposure.
A2 diagnostic criterion for combat‐related posttraumatic stress disorder
Authors: Adler Amy B. , Wright Kathleen M. , Bliese Paul D. , Eckford Rachel , Hoge Charles W.
Published: June 2008

Individuals trained to respond to a potentially traumatic event may not experience the posttraumatic stress disorder (PTSD) A2 diagnostic criterion of fear, helplessness, or horror and yet may still report significant PTSD symptoms. The present study included interviews with 202 soldiers returning from a year in Iraq. Although reporting an A2 response was associated with higher PTSD Checklist scores, there were no significant differences in the percentage of subjects who met cutoff criteria for PTSD. The most common alternative A2 responses were related to military training and anger. The A2 criterion for PTSD should be expanded so as not to underestimate the number of individuals trained for high‐risk occupations who might benefit from treatment.
Posttraumatic growth in bereaved parents
Authors: Engelkemeyer Sean M. , Marwit Samuel J.
Published: June 2008

The Posttraumatic Growth Inventory (PTGI), Revised Grief Experience Inventory, and World Assumptions Scale were administered to 111 bereaved parents. The PTGI scores indicate that many bereaved parents report personal growth in domains outlined by L.G. Calhoun and R. G. Tedeschi (2001). Grief intensity was inversely correlated with growth scores. Self‐worth was a strong predictor of growth scores, whereas assumptions about the benevolence and meaningfulness of the world were not correlated with growth.
Attachment organization, emotion regulation, and expectations of support in a clinical sample of women with childhood abuse histories
Authors: Cloitre Marylene , Stovall‐McClough Chase , Zorbas, Patty , Charuvastra Anthony
Published: June 2008

Despite the consistent documentation of an association between compromised attachment and clinical disorders, there are few empirical studies exploring factors that may mediate this relationship. This study evaluated the potential roles of emotion regulation and social support expectations in linking adult attachment classification and psychiatric impairment in 109 women with a history of childhood abuse and a variety of diagnosed psychiatric disorders. Path analysis confirmed that insecure attachment was associated with psychiatric impairment through the pathways of poor emotion regulation capacities and diminished expectations of support. Results suggest the relevance of attachment theory in understanding the myriad psychiatric outcomes associated with childhood maltreatment and in particular, the focal roles that emotion regulation and interpersonal expectations may play.
The contribution of stressful life events throughout the life cycle to combat‐induced psychopathology
Authors: Solomon Zahava , Zur‐Noah Shlomit , Horesh Danny , Zerach Gadi , Keinan Giora
Published: June 2008

This study examines the contribution of prewar life events, war exposure, and postwar life events to combat‐induced psychopathology among 425 Israeli War veterans from the Lebanon War. Data was collected at two time points (1983 and 2002). The sample included veterans with and without combat stress reaction (CSR). Battle intensity and subjective experience of risk in war were associated with CSR. Negative childhood life events, CSR, PTSD in 1983 and postwar negative life events were associated with PTSD in 2002. Furthermore, a path analysis revealed that CSR mediated the relation between battle intensity and PTSD in 2002. Our findings suggest that stressful life events throughout the life cycle contribute significantly to veterans' posttraumatic symptomatology, above and beyond combat exposure.
Estimating population prevalence of posttraumatic stress disorder: An example using the PTSD checklist
Authors: Terhakopian Artin , Sinaii Ninet , Engel Charles C. , Schnurr Paula P. , Hoge Charles W.
Published: June 2008

The PTSD Checklist (PCL) is among the most widely used self‐report instruments for assessing PTSD. To determine PCL's performance on a population level, the authors combined data from published studies that compared the PCL with structured diagnostic interviews. Weighted average sensitivities and specificities were calculated for cutoff categories most often reported in the literature. Weighted average sensitivity decreased from .85 to .39 and specificity increased from .73 to .97 for cutoffs ranging from 30 to 60. The PCL's ability to accurately estimate PTSD prevalence varied as a function of cutoff and true PTSD prevalence. In populations with a true PTSD prevalence of 15% or less, cutoff values below 44 will substantially overestimate PTSD prevalence. Uncalibrated use of the PCL for prevalence estimation may lead to large errors.
A group randomized trial of critical incident stress debriefing provided to U.S. peacekeepers
Authors: Adler Amy B. , Litz Brett T. , Castro Carl Andrew , Suvak Michael , Thomas Jeffrey L. , Burrell Lolita , McGurk Dennis , Wright Kathleen M. , Bliese Paul D.
Published: June 2008

In a group randomized trial of critical incident stress debriefing (CISD) with platoons of 952 peacekeepers, CISD was compared with a stress management class (SMC) and survey‐only (SO) condition. Multilevel growth curve modeling found that CISD did not differentially hasten recovery compared to the other two conditions. For those soldiers reporting the highest degree of exposure to mission stressors, CISD was minimally associated with lower reports of posttraumatic stress and aggression (vs. SMC), higher perceived organizational support (vs. SO), and more alcohol problems than SMC and SO. Soldiers reported that they liked CISD more than the SMC, and CISD did not cause undue distress.
Factorial invariance of posttraumatic stress disorder symptoms across three veteran samples
Authors: McDonald Scott D. , Beckham Jean C. , Morey Rajendra , Marx Christine , Tupler Larry A. , Calhoun Patrick S.
Published: June 2008

Research generally supports a 4‐factor structure of posttraumatic stress disorder (PTSD) symptoms. However, few studies have established factor invariance by comparing multiple groups. This study examined PTSD symptom structure using the Davidson Trauma Scale (DTS) across three veteran samples: treatment‐seeking Vietnam‐era veterans, treatment‐seeking post‐Vietnam‐era veterans, and Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veteran research participants. Confirmatory factor analyses of DTS items demonstrated that a 4‐factor structural model of the DTS (reexperiencing, avoidance, numbing, and hyperarousal) was superior to five alternate models, including the conventional 3‐factor model proposed by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM‐IV; American Psychiatric Association, 1994). Results supported factor invariance across the three veteran cohorts, suggesting that cross‐group comparisons are interpretable. Implications and applications for DSM‐IV nosology and the validity of symptom measures are discussed.
Posttraumatic stress symptoms, PTSD, and risk factors among lower Manhattan residents 2–3 years after the September 11, 2001 terrorist attacks
Authors: DiGrande Laura , Perrin Megan A. , Thorpe Lorna E. , Thalji Lisa , Murphy Joseph , Wu David , Farfel Mark , Brackbill Robert M.
Published: June 2008

Manhattan residents living near the World Trade Center may have been particularly vulnerable to posttraumatic stress disorder (PTSD) after the September 11, 2001 (9/11) terrorist attacks. In 2003–2004, the authors administered the PTSD Checklist to 11,037 adults who lived south of Canal Street in New York City on 9/11. The prevalence of probable PTSD was 12.6% and associated with older age, female gender, Hispanic ethnicity, low education and income, and divorce. Injury, witnessing horror, and dust cloud exposure on 9/11 increased risk for chronic PTSD. Postdisaster risk factors included evacuation and rescue and recovery work. The results indicate that PTSD is a continued health problem in the local community. The relationship between socioeconomic status and PTSD suggests services must target marginalized populations. Followup is necessary on the course and long‐term consequences of PTSD.
Macromol. Chem. Phys. 12/2008
Authors: Zhang Chi , Easteal Allan J.
Published: June 2008

Cover: In a long copolymer chain such as Pluronic F127, the mass of the two flanked ‐OH end groups is only about 0.3 wt% as compared to that of the whole macromolecule. What can these easily ignored end groups do in the physical behavior when responding to environmental temperature, particularly when the end groups are partially oxidized? The cover picture shows some significant impact on molecular arrangements and textures of the solution responding to temperature changes. Further details can be found in the article by C. Zhang* and A. J. Easteal on page 1220.
Macromol. Rapid Commun. 11/2008
Authors: Richard Fanny , Brochon Cyril , Leclerc Nicolas , Eckhardt Doreen , Heiser Thomas , Hadziioannou Georges
Published: June 2008

Back Cover: Donor‐acceptor rod‐coil block copolymers have been synthesized by Grignard metathesis polymerization of regioregular P3HT macroinitiators and nitroxide‐mediated radical polymerization of flexible blocks followed by C60 grafting reactions. These copolymers are expected to improve the solar cells active layer morphology and as a consequence the energy conversion efficiency. Further details can be found in the article by F. Richard, C. Brochon,* N. Leclerc, D. Eckhardt, T. Heiser, and G. Hadziioannouon page 885.
Synthesis and characterization of polyaniline‐multiwalled carbon nanotube nanocomposites in the presence of sodium dodecyl sulfate
Authors: Jeevananda T. , Siddaramaiah  , Kim Nam Hoon , Heo Seok‐Bong , Lee Joong Hee
Published: June 2008

Polyaniline‐carboxylic acid functionalized multi‐walled carbon nanotube (PAni/c‐MWNT) nanocomposites were prepared in sodium dodecyl sulfate (SDS) emulsion. First, the c‐MWNTs were dispersed in SDS emulsion then the aniline was polymerized by the addition of ammonium persulfate in the absence of any added acid. SDS forms the functionalized counterion in the resulting nanocomposites. The content of c‐MWNTs in the nanocomposites varied from 0 to 20 wt%. A uniform coating of PAni was observed on the c‐MWNTs by field‐emission scanning electron microscopy (FESEM). The PAni/c‐MWNT nanocomposites have been characterized by different spectroscopic methods such as UV‐Visible, FT‐Raman, and FT‐IR. The UV‐Visible spectra of the PAni/c‐MWNT nanocomposites exhibited an additional band at around 460 nm, which implies the induced doping of the MWNTs by the carboxyl group. The FT‐IR spectra of the PAni/c‐MWNT nanocomposites showed an inverse intensity ratio of the bands at 1562 and 1480 cm−1 as compared to that of pure PAni, which reveals that the PAni in the nanocomposites is richer in quinoid units than the pure PAni. The increase in the thermal stability of conductivity of the nanocomposites was due to the network structure of nanotubes and the charge transfer between the quinoid rings of the PAni and the c‐MWNTs. Copyright © 2008 John Wiley & Sons, Ltd.
New insights into form and function of fibronectin splice variants
Authors: White ES , Baralle FE , Muro AF
Published: June 2008

The extracellular matrix (ECM) is a highly dynamic structure that not only provides a physical framework for cells within connective tissues, but also imparts instructive signals for development, tissue homeostasis and basic cell functions through its composition and ability to exert mechanical forces. The ECM of tissues is composed of, in addition to proteoglycans and hyaluronic acid, a number of proteins, most of which are generated after alternative splicing of their pre‐mRNA. However, the precise function of these protein isoforms is still obscure in most cases. Fibronectin (FN), one of the main components of the ECM, is also one of the best‐known examples of a family of proteins generated by alternative splicing, having at least 20 different isoforms in humans. Over the last few years, considerable progress on elucidating the functions of the alternatively spliced FN isoforms has been achieved with the essential development of key engineered mouse strains. Here we summarize the phenotypes of the mouse strains having targeted mutations in the FN gene, which may lead to novel insights linking function of alternatively spliced isoforms of fibronectin to human pathologies. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Discovery of myopodin methylation in bladder cancer
Authors: Cebrian V , Alvarez M , Aleman A , Palou J , Bellmunt J , Gonzalez‐Peramato P , Cordón‐Cardo C , García J , Piulats JM , Sánchez‐Carbayo M
Published: June 2008

Myopodin is an actin‐binding protein that shuttles between the nucleus and the cytoplasm. After identifying an enriched CpG island encompassing the transcription site of myopodin, we aimed at evaluating the potential relevance of myopodin methylation in bladder cancer. The epigenetic silencing of myopodin by hypermethylation was tested in bladder cancer cells (n = 12) before and after azacytidine treatment. Myopodin hypermethylation was associated with gene expression, being increased in vitro by this demethylating agent. The methylation status of myopodin promoter was then evaluated by methylation‐specific polymerase chain reaction (MS‐PCR) analyses. Myopodin was revealed to be frequently methylated in a large series of 466 bladder tumours (68.7%). Myopodin methylation was significantly associated with tumour stage (p < 0.0005) and tumour grade (p = 0.037). Myopodin expression patterns were analysed by immunohistochemistry on tissue arrays containing bladder tumours for which myopodin methylation was assessed (n = 177). The presence of low nuclear myopodin expression alone (p = 0.031) or combined with myopodin methylation (p = 0.008) was associated with poor survival. Moreover, myopodin methylation in 164 urinary specimens distinguished patients with bladder cancer from controls with a sensitivity of 65.0%, a specificity of 79.8%, and a global accuracy of 75.3%. Thus, myopodin was identified to be epigenetically modified in bladder cancer. The association of myopodin methylation and nuclear expression patterns with cancer progression and clinical outcome, together with its ability to detect bladder cancer patients using urinary specimens, suggests the utility of incorporating myopodin methylation assessment in the clinical management of patients affected by uroepithelial neoplasias. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Tight junction composition is altered in the epithelium of polycystic kidneys
Authors: Yu ASL , Kanzawa SA , Usorov A , Lantinga‐van Leeuwen IS , Peters DJM
Published: June 2008

Kidney cysts in autosomal dominant polycystic kidney disease (ADPKD) undergo progressive enlargement together with luminal fluid secretion. This involves active, uphill transcellular Cl− transport which drives passive Na+ and water secretion. Implicit in this mechanism is the assumption that the paracellular permeability of the cyst epithelium to Cl− must be very low. Claudins are tight junction (TJ) transmembrane proteins that determine the ion selectivity of paracellular barriers. The aim of this study was to determine the expression and localization of claudins within renal cysts in a mouse hypomorphic model of ADPKD and in human patients. We found that the majority of cysts were of collecting duct origin. Claudins normally expressed in collecting duct (3, 4, 7, 8, and 10) were found in small cysts. However, only claudin‐7 persisted at substantive levels in the dedifferentiated epithelium of large, presumably late‐stage cysts, where it was localized both at the TJ and basolaterally. The constitutively expressed TJ proteins, ZO‐1 and occludin, were also abundantly expressed and correctly localized, suggesting that the basic infrastructure of the TJ is preserved. A previous study suggested that claudin‐7 may function as a paracellular Cl− barrier. We postulate that the role of claudin‐7 in ADPKD is to seal the paracellular route in Cl−‐secreting cyst epithelium, preventing backleak of Cl−, and that it thereby plays a permissive role in fluid secretion and cyst growth. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Gastroschisis: sonographic diagnosis, associations, management and outcome
Authors: David Anna L. , Tan Aileen , Curry Joseph
Published: June 2008

Gastroschisis is a defect in the abdominal wall, typically on the right side of a normally inserted umbilical cord through which bowel and other abdominal contents herniate. Classically, no membrane covers the herniated abdominal contents, which distinguishes the defect from exomphalos, an important differential diagnosis. Gastroschisis is usually diagnosed prenatally using ultrasound examination. The prevalence is increasing worldwide from approximately 0.1 per 10 000 total births in the 1970s to over 5 in the early 2000s. The reasons for this are unknown, but factors such as maternal smoking, recreational drugs and young maternal age are strongly associated with the defect. The increasing prevalence is causing concern because the cost of treating gastroschisis is high. Neonatal morbidity depends on significant complicating factors such as bowel atresia or necrosis and prolonged post‐operative ileus. Foetuses with gastroschisis are more likely to be born premature and with intra‐uterine growth restriction, both of which contribute to the morbidity. Gastroschisis requires early surgery after birth, often followed by prolonged neonatal care. However, advances in surgical and post‐operative care in the last decade have meant that currently 90% of affected neonates survive, with few long‐term problems. Copyright © 2008 John Wiley & Sons, Ltd.
Postnatal management and long‐term outcome for survivors with congenital diaphragmatic hernia
Authors: Chiu Priscilla , Hedrick Holly L.
Published: June 2008

Significant advances in the postnatal management of patients with congenital diaphragmatic hernia (CDH) have resulted in a remarkable improvement in survival rates over the past two decades. The success of current postnatal management of CDH patients has rendered fetal intervention to be limited to the most severe cases, and the role for prenatal treatment of CDH patients remains unclear. The adoption of lung‐preserving strategies including high‐frequency oscillatory ventilation (HFOV) and extracorporeal membrane oxygenation (ECMO) have improved CDH outcomes especially in those patients with significant ventilatory or circulatory compromise. Survival rates of up to 90% are being reported in some high‐volume centers. However, the increased survival in CDH patients has been accompanied by an increase in neurological, nutritional and musculoskeletal morbidity among the long‐term survivors. This has resulted in the need to provide resources for the long‐term follow‐up and support of this patient population. In this article, the postnatal management strategies and primary and secondary outcomes of high‐volume international pediatric surgical centers will be reviewed. Finally, the role of a multidisciplinary management team for the follow‐up of long‐term CDH survivors will be discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison between ultrasound and magnetic resonance imaging in assessment of fetal cytomegalovirus infection
Authors: Picone Olivier , Simon Isabelle , Benachi Alexandra , Brunelle Francis , Sonigo Pascale
Published: June 2008

Objective

To evaluate whether fetal brain magnetic resonance imaging (MRI) adds useful information to the one obtained by ultrasound in fetuses with cytomegalovirus (CMV) infection.

Methods

MRI and ultrasonographic findings were analyzed retrospectively in 38 fetuses with proven congenital CMV infection. Both techniques were performed on the same week at a mean gestational age of 33 weeks (24–37). The referral indications were maternal seroconversion (n = 19), and ultrasound findings (n = 19). The results were compared with the fetopathologic examination in cases with fetal death or termination of pregnancy (TOP) or the infant's neurological examination.

Results

The 38 cases were classified into three groups, depending on ultrasound findings at referral. Group 1: no ultrasound features (n = 11); group 2: extracerebral features without cerebral abnormalities at ultrasound (n = 13); group 3: presence of cerebral features at ultrasound (n = 14). In group 1, MRI was always normal. In group 2, MRI revealed cerebral features in six cases (46%). In group 3, MRI always confirmed the lesions seen at ultrasound and highlighted other cerebral features.

Conclusions

MRI can provide important additional information with regard to abnormal gyration, cerebellar hypoplasia, or abnormal signal in white matter. It is certainly useful in the assessment of fetuses with extracerebral features without brain abnormalities detected with ultrasounds. If the fetal ultrasound is strictly normal in an infected fetus, MRI may not detect brain anomalies; however, it seems difficult to not perform this noninvasive procedure. Copyright © 2008 John Wiley & Sons, Ltd.
Low‐pressure rate coefficients of the reaction of O(3P) with CF3I and CH3I
Authors: Teruel Mariano A.
Published: June 2008

Absolute rate coefficients for the gas‐phase reactions of CF3I and CH3I with O(3P) atoms were measured at 298 K by the discharge flow technique coupled to resonance fluorescence to monitor O(3P) atoms. This is the first kinetic study for these reactions under low‐pressure conditions (1.56–3.26 Torr). The overall rate coefficients were (5.2 ± 0.7) × 10−12 and (2.3 ± 0.3) × 10−11 cm3 molecule−1 s−1, respectively. The experiments were carried out under pseudo‐first‐order conditions with [O(3P)]0 ≪ [RI]0.

The results are compared with previous measurements using different experimental techniques at higher pressures. Free energy relationships and atmospheric implications are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Anomeric effect plays a major role in the conformational isomerism of fluorinated pnictogen compounds
Authors: Martins Levindo E. , Freitas Matheus P.
Published: June 2008

According to our theoretical studies, the anomeric effect, an stereoelectronic interaction between lone pair and a vicinal antibonding orbital, has shown to contribute decisively for the conformational isomerism of 1‐fluoro‐N,N‐dimethylmethanamine (1) and of its corresponding P, As and Sb analogues (2–4). CX bonds in 2–4 are larger than in the parent compound 1, thus providing a LPX/CF* interaction progressively weaker on going from 1 to 4. However, such hyperconjugation contributed by more than 1.3 kcal mol−1 for the stabilization of anti conformer in 4 (θLPXCF = 180°), increasing to 24.1 kcal mol−1 in 1. An isodesmic reaction model supported these findings. Copyright © 2008 John Wiley & Sons, Ltd.
Structural and aromatic aspects of tautomeric equilibrium in hydroxy aryl Schiff bases
Authors: Filarowski A. , Kochel A. , Kluba M. , Kamounah F. S.
Published: June 2008

The synthesis and X‐ray measurements of four Schiff bases were carried out at 100 K. The HOMA and HOSE aromaticity indices were estimated on the basis of the experimental data. The aromaticity of the phenyl ring and the chelate chain was analysed. A comparison of the aromaticity of naphthalene and phenyl derivatives of hydroxy aryl Schiff bases is presented. The balance between the aromaticity of adjacent rings of the naphthalene fragment and its effect on proton transfer is defined. Research on the interrelations between aromaticity and the intramolecular proton transfer in hydroxy aryl Schiff bases is shown. Copyright © 2008 John Wiley & Sons, Ltd.
The herbicide flamprop‐M‐methyl has a new antimicrotubule mechanism of action
Authors: Tresch Stefan , Niggeweg Ricarda , Grossmann Klaus
Published: June 2008

BACKGROUND: The herbicidal mode of action of flamprop‐M‐methyl [methyl N‐benzoyl‐N‐(3‐chloro‐4‐fluorophenyl)‐D‐alaninate] was investigated.

RESULTS: For initial characterization, a series of bioassays was used, which indicated a mode of action similar to that of mitotic disrupter herbicides. Cytochemical fluorescence studies, which included monoclonal antibodies against polymerized tubulin, were applied to elucidate effects on mitosis and microtubule assembly in maize roots. When seedlings were root treated with 50 µM of flamprop‐M‐methyl, cell division activity in meristematic root tip cells ceased within 4 h. The compound severely disturbed the orientation of spindle and phragmoblast microtubules, leading to defective spindle and phragmoblast structures. Cortical microtubules were only slightly affected. In late anaphase and early telophase cells, phragmoblast microtubules were disorganized in multiple arrays that hampered regular cell plate deposition in cytokinesis. Microtubules of the spindle apparatus were found attached to chromosomal kinetochores, but did not show regular organization associated with a zone of microtubule‐organizing centres at the opposite ends of the cell. On account of this loss of spindle organization, chromosomes remained in a condensed state of prometaphase or metaphase. Unlike known microtubule disrupter herbicides, flamprop‐M‐methyl and its biologically active metabolite flamprop did not inhibit soybean tubulin polymerization to microtubules in vitro at 50 µM. In contrast, soybean plants responded sensitively to the compounds.

CONCLUSION: The results indicate that flamprop‐M‐methyl is a mitotic disrupter herbicide with a new antimicrotubule mechanism of action that affects orientation of spindle and phragmoblast microtubules, possibly by minus‐end microtubule disassembly. Copyright © 2008 Society of Chemical Industry
M ‐plane InGaN/GaN light emitting diodes fabricated by MOCVD regrowth on c ‐plane patterned templates
Authors: Schaake Christopher A. , Fichtenbaum Nicholas A. , Neufeld Carl J. , Keller Stacia , DenBaars Steven P. , Speck James S. , Mishra Umesh K.
Published: June 2008

In this work we demonstrate a light emitting diode (LED) with m ‐plane quantum wells fabricated on a (000$ \bar 1 $) template. N‐polar, n‐type GaN was grown by MOCVD on vicinal sapphire substrates. Stripes, measuring 500 nm wide, 500 nm tall and spaced 2 μm apart, were etched parallel to the 〈11$ \bar 2 $0〉 direction leading to sidewalls that are approximately {10$ \bar 1 $0}. Sputtered AlN was used as a regrowth mask on the c ‐plane surfaces. An active region consisting of 5 InGaN quantum wells and GaN barriers followed by p‐type was grown. The regrowth occurred mostly on the exposed m ‐plane sidewalls, leading to lateral growth in the 〈10$ \bar 1 $0〉 direction. The LED was processed using conventional methods. A thick metal contact was used to connect the p‐regions together. Current vs. voltage measurements showed good rectifying behavior with a turn on of about 6 volts. On‐wafer electroluminescence measurements revealed a peak wavelength of 422 nm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrafast photoexcited carrier dynamics in GaAs:Er,O by pump and probe transmission spectroscopy
Authors: Shimada K. , Takemoto S. , Hidaka K. , Terai Y. , Tonouchi M. , Fujiwara Y.
Published: June 2008

Ultrafast dynamics of photoexcited carriers in Er,O‐codoped GaAs (GaAs:Er,O) and Er‐doped GaAs (GaAs:Er) have been investigated by means of pump and probe transmission spectroscopy, and discussed in relation to Er‐related photoluminescence (PL) intensity. Time‐resolved transmission signal in undoped GaAs showed a temporal increase due to saturation of optical absorption, and then decreased reflecting the recovery of the absorption. The decrease consisted of two components corresponding to intra‐band relaxation (< 1 ps) and inter‐band relaxation (> 50 ps). In GaAs:Er,O and GaAs:Er, on the other hand, an additional component was observed. The relaxation time was 4 ∼ 11 ps. This relaxation time, assigned to carrier trapping time by an Er‐related trapping, became short with increasing Er‐related PL intensity. These results suggest the fast carrier capturing plays an important role for the enhancement of the Er‐related luminescence. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Be‐doping on InGaN/GaN nanocolumn light‐emitting diode structures by rf‐plasma‐assisted molecular‐beam epitaxy
Authors: Sekiguchi Hiroto , Kato Kei , Kikuchi Akihiko , Kishino Katsumi
Published: June 2008

GaN nanocolumns are one‐dimensional high‐quality dislocation‐free nano‐crystals. The effect of Be‐doping on GaN nanocolumns was investigated using InGaN/GaN nanocolumn LED structure grown by RF‐plasma‐assisted molecular‐beam epitaxy. Be was doped into the upper cladding region of the nanocolumn light‐emitting diodes (LEDs). Be is expected to be a p‐type dopant of GaN with a shallow accepter level, but p‐type conductivity was not obtained in these experiments. However, we observed a remarkable enhancement of the lateral growth of the GaN nanocolumn by Be doping; that is, the surface of the Be‐doped region became smooth and continuous with increasing Be doping concentration. The root mean square (RMS) surface roughness was reduced from 35 to 10 nm with increasing Be cell temperature from 710 to 975 °C. Cross‐sectional TEM observation revealed that no threading dislocations were generated in the observed area at the conjunction boundary between neighboring nanocolumns during lateral growth. This suggests that a high‐quality overgrowth layer with a low threading dislocation density can be realized on Be‐doped GaN nanocolumns. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effects of GaAs interval layer on GaNAs/GaAs superlattice structure grown by RF‐MBE using modulated N radical beam sequence
Authors: Fujii Kensuke , Kumamoto Tsuneaki , Oda Yuichi , Nishioka Ayami , Miyagawa Hayato , Tanaka Yasuhiro , Koshiba Shyun
Published: June 2008

We have investigated the effects of GaAs interval layers on the structure of GaNAs/GaAs superlattices (SLs) grown by radio‐frequency molecular beam epitaxy. As the results of x‐ray diffraction, it is found that periodic structure of GaNAs/GaAs SL is better in the case of thicker GaAs layer than that of thin GaAs layer, whereas the GaNAs layer thickness is constant of 10 ML. Transmission electron microscope (TEM) studies of SL samples clearly demonstrate the drastic effects of GaAs layer thickness on the GaNAs/GaAs SL structures. High resolution TEM study of the sample with a thin AlAs layer inserted between GaNAs and GaAs, for improved contrast, reveals existence of the roughening process during GaNAs layer growth and the smoothing process during GaAs layer growth. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Commercial GaInNAs VCSELs grown by MBE
Authors: Jewell J. , Graham L. , Crom M. , Maranowski K. , Smith J. , Fanning T. , Schnoes M.
Published: June 2008

Vertical‐cavity surface‐emitting lasers (VCSELs) emitting in the 1260‐1650 nm band are desired for low‐cost, low‐power optical communications on single‐mode fibers. Use of the GaInNAs material system [3], grown on GaAs substrates by molecular beam epitaxy (MBE), has yielded the best reproducibility, performance and reliability [1, 2]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies of optical emission in the high intensity pumping regime of top‐down ZnO nanostructures and thin films grown on c‐sapphire substrates by pulsed laser deposition
Authors: Divay L. , Rogers D. J. , Lusson A. , Kostcheev S. , Murtry S. Mc , Lérondel G. , Téhérani F. Hosseini
Published: June 2008

We report on the emission of Zinc Oxide (ZnO) thin films obtained by Pulsed Laser Deposition (PLD) under high intensity excitation. In order to clarify the origin of the emission bands, we compared results for high quality thin films (75 nm) before and after “top‐down” nanopatterning. A nanopattering technique was developed for this purpose. The technique combined Electron Beam Lithography (EBL) and lift‐off techniques and Inductively Coupled Plasma Reactive Ion Etching (ICP RIE). The emission spectra of the two types of samples were found to have a difference in their fine structure that was attributed, in part, to the existence of guided emission in the thin films and exciton weak confinement effects in the nanostructures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin selective optical excitation in charge‐tunable GaAs quantum dots
Authors: Sanada Haruki , Sogawa Tetsuomi , Gotoh Hideki , Kamada Hidehiko , Yamaguchi Hiroshi , Nakano Hidetoshi
Published: June 2008

Spin selective optical excitation using polarizationresolved photoluminescence spectroscopy is demonstrated in a single charge‐tunable GaAs quantum dot. The degree of circular polarization of the luminescence emitted from a negative trion strongly depends on the excitation energy at a specific bias voltage. We discuss the effect of the trion formation processes via trion excited states on spin orientation in quantum dots. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanically detected field‐induced Mn spin rotation in GaMnAs
Authors: Onomitsu Koji , Mahboob Imran , Okamoto Hajime , Yamaguchi Hiroshi
Published: June 2008

To study the magnetization properties of a micron‐sized GnMnAs film, we characterize the mechanical properties of a micro‐cantilever integrating a GaMnAs Hall bar. The magnetic field dependence of its mechanical resonance frequency below the Curie temperature is remarkably different from that above the Curie temperature. The frequency shift, which reflects the field‐induced Mn spin rotation, is mainly caused by the magnetoelastic coupling. This result demonstrates that a micromechanical cantilever is a powerful tool for investigating the magnetic properties of micrometer‐sized ferromagnetic materials. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Habitat used by Macrhybopsis chubs associated with channel modifying structures in a large regulated river: implications for river modification
Authors: Ridenour Clayton J. , Starostka Andrew B. , Doyle Wyatt J. , Hill Tracy D.
Published: June 2008

We examined use of channel modifying structures (CMS; e.g., engineered rock dikes, channel sandbars) and their associated smaller spatial‐scale habitats (SSH) on lower Missouri River, USA, by speckled chub (Macrhybopsis aestivalis), sicklefin chub (M. meeki) and sturgeon chub (M. gelida) from June through October, 2006 to identify important habitat characteristics that could aid conservation. We sampled chubs primarily in six CMS types: L‐dikes, wing‐dikes, kicker dikes, rootless dikes, channel sandbars and bank‐lines. Ninety‐three per cent of chubs were collected from L‐dikes, wing‐dikes and channel sandbars. Unidentifiable Macrhybopsis chubs (UHY) were less than 35‐mm TL, were collected early in the sampling season and were most associated with L‐dikes where mean bottom current velocity was slow (0.07 m/s). Chubs large enough to be identified to species were associated with large channel sandbars where mean bottom current velocity was faster (0.34 m/s). Chubs from wing‐dikes were more abundant in shallow water (<1.2 m deep) adjacent to bars than in deeper (>1.2 m deep), open‐water areas (p = 0.007). Month accounted for 54% and CMS with SSH 18% of explained variation in chub species distribution and abundance. Our results demonstrate that CMS in the contemporary lower Missouri River channel provide multiple habitats for multiple life‐stages of Macrhybopsis chubs (e.g., nursery and post‐nursery habitats). L‐ and wing‐dikes may provide surrogate nursery habitats for chubs where in‐channel slow‐velocity areas were lost after river channelization. Managing CMS to address life history stages and an ecologically appropriate proportion and distribution of dike to channel sandbar habitats may be critical for conservation of native Macrhybopsis chubs in lower Missouri River. Published in 2008 by John Wiley & Sons, Ltd.
Shareholder activism for corporate social responsibility: what do we know?
Authors: Sjöström Emma
Published: June 2008

There is a growing body of research on shareholder activism for corporate social and environmental responsibility. This paper maps and synthesizes research on this topic during 1983–2007. Five key themes emerge. (1) Several studies address shareholder proposals in the US, including proposal topics, voting results, and typical targets for such activism. (2) Other studies focus on the effects of shareholder activism on corporate policy and practice. Further, studies have been conducted on shareholder activism by (3) NGOs, (4) unions and (5) pension funds respectively. Based on this review, missing perspectives are identified and suggestions are made for future research directions. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
Stress and placental resistance measured by Doppler ultrasound in early and mid‐pregnancy
Authors: Harville E. W. , Savitz D. A. , Dole N. , Herring A. H. , Thorp J. M. , Light K. C.
Published: June 2008

Objectives

To examine the association between self reports and biomarkers of stress and placental resistance (measured by Doppler ultrasound of the uterine and umbilical arteries), to determine if restriction of blood flow to the placenta is a mechanism by which stress might affect health during pregnancy.

Methods

Eight hundred and seventy‐two women had ultrasound examinations of the uterine artery at 15–19 weeks' gestation and the uterine and umbilical arteries at 24–29 weeks, and resistance and pulsatility indices were calculated. Psychosocial stress was measured by telephone interview and self‐administered questionnaire using several validated tools twice during the pregnancy. Cortisol and corticotropin‐releasing hormone (CRH) were measured twice during the pregnancy. Linear and hierarchical models were used to examine the relationships among reported stress, stress hormones and placental Doppler indices.

Results

The umbilical artery resistance index was higher in younger women, those with less education, those who were single and those who smoked. The uterine artery pulsatility index was higher in women with pre‐eclampsia, those living alone, those with high body mass index, and those who gained the least weight during pregnancy. A higher CRH level was associated with small increases in uterine artery pulsatility and umbilical artery resistance indices. Psychosocial measures of stress were not consistently associated with higher placental resistance.

Conclusions

Increased CRH levels may be associated with increased placental resistance. Otherwise, these findings do not support the hypothesis that restriction of blood flow to the fetus is a major mechanism by which stress affects infant health. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Pulmonary Resection for Metastatic Head and Neck Cancer
Authors: Chen Fengshi , Sonobe Makoto , Sato Kiyoshi , Fujinaga Takuji , Shoji Tsuyoshi , Sakai Hiroaki , Miyahara Ryo , Bando Toru , Okubo Kenichi , Hirata Toshiki , Date Hiroshi
Published: June 2008

Background

Pulmonary metastasectomy has become the standard therapy for various metastatic malignancies to the lungs; however, little data have been available about lung metastasectomy for head and neck cancers. To confirm a role for resection of pulmonary metastases for such tumors, we reviewed our institutional experience.

Methods

Between 1991 and 2007, 20 patients with pulmonary metastases from head and neck cancers underwent complete pulmonary resection. All patients had obtained or had obtainable locoregional control of their primary head and neck cancers. Various perioperative variables were investigated retrospectively to analyze the prognostic factors for overall survival and disease‐free survival after metastasectomy.

Results

Of the 20 patients, 10 (50%) had squamous cell carcinoma, 7 (35%) had adenoid cystic carcinoma, and 3 had miscellaneous carcinomas. The median disease‐free interval from the time of treatment of the head and neck primary cancers to the development of pulmonary metastases was 27 months. Overall survival rate after metastasectomy was 59.4% at 5 years and 47.5% at 10 years, respectively. Disease‐free survival rate was 25.0% at 5 years after pulmonary resection. A disease‐free interval equal to or longer than 12 months was a significantly favorable prognostic factor for both overall survival and disease‐free survival (p = 0.02 and 0.01, respectively). Patients with squamous cell carcinoma and male sex showed a worse overall survival (p = 0.04 and 0.03, respectively).

Conclusion

The current practice of pulmonary metastasectomy for head and neck cancers in our institution was well justified. A disease‐free interval equal to or longer than 12 months, nonsquamous cell carcinoma, and female sex might be relevant to a better prognosis.
Incidental Pancreatic Cystic Lesions
Authors: Edirimanne Senarath , Connor Saxon J.
Published: June 2008

Introduction

Incidental pancreatic cystic lesions (IPCL) are becoming an increasingly frequent clinical entity. Within this review, the differential diagnosis, investigation, and management are discussed.

Methods

A MEDLINE search was performed for IPCL.

Results

Incidence of IPCL varies from 0.2–0.7%, and 30–47% are premalignant or malignant. Pancreatic pseudocysts (PC), serous cystic neoplasms (SCN), intraductal papillary mucinous neoplasms (IPMN), and mucinous cystic neoplasms (MCN) are the most common pathological entities of IPCL. The use of combined modalities, including clinical characteristics, serum tumor markers, cross‐sectional imaging, and endoscopic ultrasound (EUS) with cyst fluid analysis should all be used to establish an accurate preoperative diagnosis if possible. Modern multidetector computed tomography (MDCT) and magnetic resonance pancreatography (MRP) allow detailed characterization of IPCL, including size, septation, calcifications, mural nodules, and communication with main pancreatic duct. The best available cyst fluid markers of mucinous neoplasm are viscosity ≥1.6 and carcinoembryonic antigen >192 ng/ml. Although surgery is indicated for MCN or main or mixed duct IPMN, recent advances in the understanding of the natural history and increasingly accurate preoperative diagnosis allow a nonoperative approach to be undertaken for the majority of IPCL. For those treated nonoperatively, the ideal follow‐up has yet to be determined.

Conclusions

Emerging evidence supports selective nonoperative management for the majority of patients who have IPCL when investigated by a multimodal approach. For those in whom a suspicion of malignancy remains, surgery is indicated.
The Right Small‐for‐Size Graft Results in Better Outcomes than the Left Small‐for‐Size Graft in Adult‐to‐Adult Living Donor Liver Transplantation
Authors: Yi Nam‐Joon , Suh Kyung‐Suk , Cho Yong Beom , Lee Hae Won , Cho Eung‐Ho , Cho Jai Young , Shin Woo Young , Kim Joohyun , Lee Kuhn Uk
Published: June 2008

Background

The recent outcome of adult‐to‐adult living donor liver transplantation (ALDLT) using small‐for‐size grafts (SFSGs; GRWR <0.8%) has been excellent after right grafts were exclusively used in large‐volume ALDLT centers.

Methods

We compared the outcome of ALDLTs using 11 right SFSGs (group R) with that using 18 left SFSGs (group L) of our center. The dysfunction of graft was defined dysfunction as hyperbilirubinemia (>5 mg/dl), prolonged prothrombin time (>2 INR), or uncontrolled ascites (>1,000 ml/day) on 3 consecutive days in posttransplant 7 days, and the dysfunction score (DS; the sum of points given per each sign) of the graft was used to describe the SFSG dysfunction severity.

Results

The pretransplant recipient status was similar between the groups, but the 1‐year mortality rate was 0% in group R and 33.3% (n = 6) in group L (p = 0.038). The ICU stay was longer in group L (20 days) than in group R (11 days; p = 0.004). Hyperbilirubinemia in group R vs. L was noted in 54.5% vs. 50%, prolonged prothrombin time in 18.2% vs. 50%, and uncontrolled ascites in 54.5% vs. 100%. The DS was lower in group R than in group L (1.3 vs. 2; p = 0.007). The DS was zero in four right liver recipients. On multivariate analysis, the only factor affecting DS was the graft side.

Conclusion

The clinical signs of SFSG dysfunction were less arduous and there was no 1‐year mortality in cases in group R. Therefore, the right SFSG may be used for ALDLT in the future base on the transplant center’s experience.