bluuebunny/crossref_metadata_2025 huggingface dataset:
Reciprocal Modifications of CLIC4 in Tumor Epithelium and Stroma Mark Malignant Progression of Multiple Human Cancers
Authors: Suh Kwang S. , Crutchley John M. , Koochek Arash , Ryscavage Andrew , Bhat Kiran , Tanaka Takemi , Oshima Akira , Fitzgerald Peter , Yuspa Stuart H.
Published: January 2007

Purpose: CLIC4, a member of a family of intracellular chloride channels, is regulated by p53, c-Myc, and tumor necrosis factor-α. Regulation by factors involved in cancer pathogenesis, together with the previously shown proapoptotic activity of CLIC4, suggests that the protein may have a tumor suppressor function. To address this possibility, we characterized the expression profile, subcellular localization, and gene integrity of CLIC4 in human cancers and determined the functional consequences of CLIC4 expression in tumor epithelium and stromal cells.

Experimental Design: CLIC4 expression profiles were analyzed by genomics, proteomics, bioinformatics, and tissue microarrays. CLIC4 expression, as a consequence of crosstalk between stroma and epithelium, was tested in vitro by coculture of breast epithelial tumor cells and normal fibroblasts, and the functional consequences of CLIC4 expression was tested in vivo in xenografts of human breast tumor cell lines reconstituted with CLIC4 or mixed with fibroblasts that overexpress CLIC4 transgenically.

Results: In cDNA arrays of matched human normal and tumor tissues, CLIC4 expression was reduced in renal, ovarian, and breast cancers. However, CLIC4 protein levels were variable in tumor lysate arrays. Transcript sequences of CLIC4 from the human expressed sequence tag database and manual sequencing of cDNA from 60 human cancer cell lines (NCI60) failed to reveal deletion or mutations in the CLIC4 gene. On matched tissue arrays, CLIC4 was predominantly nuclear in normal human epithelial tissues but not cancers. With advancing malignant progression, CLIC4 staining became undetectable in tumor cells, but expression increased in stromal cells coincident with up-regulation of α-smooth muscle actin, suggesting that CLIC4 is up-regulated in myofibroblasts. Coculture of cancer cells and fibroblasts induced the expression of both CLIC4 and α-smooth muscle actin in fibroblasts adjacent to tumor nests. Introduction of CLIC4 or nuclear targeted CLIC4 via adenovirus into human breast cancer xenografts inhibited tumor growth, whereas overexpression of CLIC4 in stromal cells of xenografts enhanced tumor growth.

Conclusion: Loss of CLIC4 in tumor cells and gain in tumor stroma is common to many human cancers and marks malignant progression. Up-regulation of CLIC4 in tumor stroma is coincident with myofibroblast conversion, generally a poor prognostic indicator. Reactivation and restoration of CLIC4 in tumor cells or the converse in tumor stromal cells could provide a novel approach to inhibit tumor growth.
Reversing Hepatocellular Carcinoma Progression by Using Networked Biological Therapies
Authors: Epstein Richard J. , Leung Thomas W.
Published: January 2007

The liver is distinguished from other tissues by (a) its detoxifying function, (b) its resistance to apoptosis, and (c) its regenerative response to damage. Hepatocellular carcinoma arises when chronic insults, such as hepatitis or iron overload, constitutively activate this regenerative program. Here, we propose that the proliferative response of the liver to damage underlies the resistance of hepatocellular carcinoma to cytotoxic therapy, and that hepatocellular carcinoma growth should therefore be more readily controlled by using a networked combination of noncytotoxic interventions to interrupt the damage-inducible regenerative pathway. To this end, hepatocellular carcinoma boasts a wealth of potential drug targets, including viral replication, the antiapoptotic immunosuppressant α-fetoprotein, hepatic iron overload, inflammatory signaling, extracellular proteases, and growth factors. By blocking these positive feedback loops in parallel, and so returning the host environment to a more normal state, epigenetic repression of tumor-suppressor gene function may be reversed and tumor dormancy restored. Noncytotoxic maneuvers that short circuit damage resistance loops may thus represent an indirect form of gene therapy meriting incorporation into hepatocellular carcinoma clinical trials.
Hyperhomocysteinemia Alters Cardiac Substrate Metabolism by Impairing Nitric Oxide Bioavailability Through Oxidative Stress
Authors: Suematsu Nobuhiro , Ojaimi Caroline , Kinugawa Shintaro , Wang Zipping , Xu Xiaobin , Koller MD Akos , Recchia Fabio A. , Hintze Thomas H.
Published: January 2007

Background—

Hyperhomocysteinemia (HHcy) has been considered a vascular disease associated with increased levels of oxidative stress that results in scavenging of NO. However, little is known of the impact of HHcy on cardiac function and especially myocardial metabolism.

Methods and Results—

L-Homocysteine was intravenously infused into conscious dogs, and the dogs were fed methionine to increase plasma homocysteine to 10 μmol/L for acute and 24 μmol/L for chronic HHcy. There was no significant change in hemodynamics with HHcy. Veratrine-induced, NO-dependent, coronary vasodilation (Bezold-Jarisch reflex) was reduced by 32% but was restored by simultaneous intravenous infusion of ascorbic acid or apocynin. Acute and chronic HHcy significantly increased uptake of glucose and lactate and decreased uptake of free fatty acid by the heart. HHcy significantly decreased bradykinin- or carbachol-induced reduction of myocardial oxygen consumption in vitro, and this effect was completely restored by coincubation with ascorbic acid, Tempol, or apocynin. Western blot analysis indicated an increase in Nox2 (82%) and a reduction in endothelial nitric oxide synthase (39%), phospho-endothelial nitric oxide synthase (39%), and superoxide dismutase-1 (45%). Microarray analysis of gene expression in heart tissue from chronic HHcy indicated a switch in cardiac phenotype to enzymes that metabolize glucose.

Conclusions—

HHcy directly modulates substrate use by the heart independent of changes in hemodynamics or ventricular function by reducing NO bioavailability through the generation of superoxide. The progression of cardiac or coronary heart disease associated with HHcy should be evaluated in light of the impact of alterations in the regulation of cardiac metabolism and substrate use.
Cdc2-mediated Schwann cell migration during peripheral nerve regeneration
Authors: Han In Sun , Seo Tae Beom , Kim Kwan-Hoi , Yoon Jin-Hwan , Yoon Sung-Jin , Namgung Uk
Published: January 2007

Schwann cell migration facilitates peripheral nerve regeneration after injury. We have recently found increased activation of Cdc2 kinase in regenerating sciatic nerves. Here we show that Cdc2 phosphorylation of caldesmon regulates Schwann cell migration and nerve regeneration. A robust but transient increase in Cdc2 expression was found in cultured Schwann cells prepared from the sciatic nerve in rats that had undergone crush injury for 7 days. These `injury-preconditioned' Schwann cells exhibited enhanced migration compared with non-preconditioned control cells and treatment with the cdk inhibitor roscovitine prevented cell migration. After transduction with recombinant Cdc2 DNA adenoviral vectors, Schwann cells were implanted into sciatic nerves; those expressing wild-type Cdc2 migrated further in the distal direction than those expressing dominant-negative Cdc2. We identified caldesmon as a downstream substrate of Cdc2 in Schwann cells and its phosphorylation by Cdc2 changed its subcellular localization. Overexpression of dominant-negative caldesmon significantly counteracted the migration effect caused by Cdc2. Finally, neurite outgrowth of cultured DRG sensory neurons, facilitated by co-culture with injury-preconditioned Schwann cells, was suppressed by roscovitine treatment. The results indicate that activation of the Cdc2-caldesmon pathway is necessary for Schwann cell migration and suggest a role for this pathway in peripheral axonal growth.
Probable Statin-Induced Testicular Pain
Authors: Linnebur Sunny A , Hiatt William H
Published: January 2007

Objective:

To describe a case of a patient experiencing testicular pain on 3 occasions after taking 3 different statins.

Case Summary:

A 54-year-old man with hyperlipidemia was started on lovastatin therapy. His other medications included aspirin, levothyroxine, buspirone, and atenolol. Seven months after starting lovastatin, the patient experienced testicular discomfort that resolved upon discontinuation of the drug. Afterward, he started simvastatin and again experienced testicular discomfort. The simvastatin was changed to atorvastatin, and the pain resolved. However, 3 months after starting atorvastatin, the patient developed testicular pain, which resolved after the drug was stopped. During each of the episodes, the patient's pain increased when he was sitting, driving, or wearing tight clothing. The Naranjo probability scale indicates that statins probably caused the patient's pain.

Discussion:

Testicular pain is rarely caused by medications. Product labeling for statins does not list urinary adverse events as common. However, labeling for atorvastatin and pravastatin lists rare urologic adverse effects. A literature search did not reveal any previously reported cases of testicular adverse effects from statins. However, statins have been shown to inhibit cholesterol synthesis in the testis. Some data indicate that statins reduce serum testosterone concentrations, but other data indicate that statins have no effect on sex hormones or spermatogenesis. Data are also available indicating that aspirin might affect testosterone concentrations and testicular function. It is difficult to know whether either of the above hormonal mechanisms was associated with our patient's testicular discomfort, but the time course and challenge/rechallenge aspects of the case suggest that the statins were the cause.

Conclusions:

Urologic adverse effects of statins rarely occur but should not be overlooked by medical providers.
Barriers to the Identification and Management of Psychosocial Issues in Children and Maternal Depression
Authors: Horwitz Sarah McCue , Kelleher Kelly J. , Stein Ruth E.K. , Storfer-Isser Amy , Youngstrom Eric A. , Park Elyse R. , Heneghan Amy M. , Jensen Peter S. , O'Connor Karen G. , Hoagwood Kimberly Eaton
Published: January 2007

CONTEXT. Child psychosocial issues and maternal depression are underidentified and undertreated, but we know surprisingly little about the barriers to identification and treatment of these problems by primary care pediatricians.

OBJECTIVES. The purpose of this work was to determine whether (1) perceived barriers to care for children's psychosocial issues and maternal depression aggregate into patient, physician, and organizational domains, (2) barrier domains are distinct for mothers and children, and (3) physician, patient, and practice/organizational characteristics are associated with different barrier domains for children and mothers.

METHODS. We conducted a cross-sectional survey of the 50818 US nonretired members of the American Academy of Pediatrics. Of a random sample of 1600 members, 832 (745 nontrainee members) responded. This was a mailed 8-page survey with no patients and no intervention. We measured physician assessment of barriers to providing psychosocial care for children's psychosocial problems and maternal depression.

RESULTS. Pediatricians frequently endorse the lack of time to treat mental health problems (77.0%) and long waiting periods to see mental health providers (74.0%) as the most important barriers to the identification and treatment of children's psychosocial problems. For maternal depression, pediatricians most often endorsed lack of training in treatment (74.5%) and lack of time to treat (64.3%) as important barriers. Pediatricians' reports of barriers clustered into physician and organizational domains. Physician domains were distinct for children and mothers, but organizational domains were not. Several physician and practice characteristics are significantly associated with the 4 barrier scales, and different characteristics (eg, sociodemographic, attitudinal, and practice features) were related to each barrier area.

CONCLUSIONS. Pediatricians endorse a wide range of barriers with respect to the diagnosis and treatment of children's mental health problems and maternal depression. The specificity of factors relating to various barrier areas suggests that overcoming barriers to the identification and treatment of child mental health problems and maternal depression in primary care pediatrics is likely to require a multifaceted approach that spans organizational, physician, and patient issues. In addition, comprehensive interventions will likely require social marketing approaches designed to engage diverse audiences of clinicians and their patients to participate.
An Unusual Case of Severe Therapy-Resistant Hypertension in a Newborn
Authors: Kiessling Stefan G. , Wadhwa Nitin , Kriss Vesna M. , Iocono Joseph , Desai Nirmala S.
Published: January 2007

Hypertension can occur in up to 2% of neonates, and the spectrum of potential causes is broad. Prompt and thorough evaluation with a main focus on kidney disease is key for appropriate therapy. Here we describe a 2-day-old neonate with feeding intolerance and elevated blood pressure readings. Within 24 hours after birth, the infant's blood pressure increased significantly, with sustained mean arterial pressure >85. Renal Doppler ultrasound showed decreased venous blood flow in the right kidney with an abnormal Doppler wave form suggestive of unilateral renal venous thrombosis. Despite aggressive antihypertensive therapy including hydralazine and enalaprilat, hypertension remained sustained. On day-of-life 4, the infant developed clinical signs of hypertensive encephalopathy and significant cardiac dysfunction. A renal angiography showed complete, likely thrombotic occlusion of the right renal artery. Renal MAG3 imaging showed minimal function of the affected kidney, and a nephrectomy secondary to medically uncontrollable hypertension and worsening cardiac dysfunction was performed. The child is developing normally in all aspects on follow-up evaluations at 6 months and 1 year of age. Reevaluation of the working diagnosis in neonates with hypertension can be necessary to optimize the outcome. The overall prognosis can be excellent even in newborns with profound cardiac and neurologic involvement.
SunSafe in the Middle School Years: A Community-wide Intervention to Change Early-Adolescent Sun Protection
Authors: Olson Ardis L. , Gaffney Cecelia , Starr Pamela , Gibson Jennifer J. , Cole Bernard F. , Dietrich Allen J.
Published: January 2007

OBJECTIVE. Rising rates of skin cancer associated with early-life sun exposure make it important to improve adolescent sun-protection practices. Our study objective was to determine if a multicomponent community-wide intervention could alter the decline in sun protection that begins in early adolescence.

METHODS. A randomized, controlled trial was conducted in 10 communities to assess the impact of the SunSafe in the Middle School Years program. The intervention sought to (1) educate and activate adults and peers to role model and actively promote sun-protection practices and (2) create a pro–sun protection community environment. It targeted school personnel, athletic coaches, lifeguards, and clinicians and enlisted teens as peer advocates. Annual observations of cross-sectional samples of teens at community beach/pool sites were used to assess the impact of 1 and 2 years of intervention exposure compared to grade-matched controls. The outcome was percent of body surface protected by sunscreen, clothing, or shade.

RESULTS. Observers determined the sun protection level of 1927 adolescents entering 6th to 8th grades. After 2 years of intervention exposure, adolescents at the beach/pool in intervention communities were significantly better protected than those in control communities. Over 2 years, the percent of body surface area protected declined by 23% in the control arm but only 8% in intervention arm. After intervention, the average percent of body surface protected at intervention sites (66.1%) was significantly greater than control sites (56.8%). Teens in intervention communities reported sun-protection advice from more adult sources, were more likely to use sunscreen, and applied it more thoroughly than control-site teens.

CONCLUSIONS. Our multicomponent model addressing adolescent sun protection shows the power of engaging teens and adults from across the community as role models and educators. This new ecological approach shows promise in changing adolescent sun protection behaviors and reducing skin cancer risks.
Accuracy and Interpretation of Rapid Influenza Tests in Children
Authors: Grijalva Carlos G. , Poehling Katherine A. , Edwards Kathryn M. , Weinberg Geoffrey A. , Staat Mary A. , Iwane Marika K. , Schaffner William , Griffin Marie R.
Published: January 2007

BACKGROUND. Influenza rapid antigen detection (rapid tests) can provide timely identification of infection and aid in clinical decision-making. Although the interpretation of test results depends on test characteristics and influenza prevalence, this information is limited in routine clinical practice.

OBJECTIVE. We sought to assess the times at which rapid tests are most predictive of influenza infection.

METHODS. The New Vaccine Surveillance Network enrolled children aged <5 years who were hospitalized with respiratory symptoms or fever from October 2000 through September 2004. Nasal and throat swabs were obtained, and influenza virus was detected by culture and reverse-transcription polymerase chain reaction. Provider-ordered rapid influenza tests were compared with the criterion standard (culture and reverse-transcription polymerase chain reaction) to determine their sensitivity and specificity. The New Vaccine Surveillance Network also enrolled children in outpatient settings during the 2002–2003 and 2003–2004 influenza seasons and determined the weekly influenza prevalence among symptomatic children. Trends in weekly predictive values of the rapid tests were estimated over the influenza seasons.

RESULTS. Rapid influenza tests had an overall sensitivity of 63% and specificity of 97%. In 2002–2003, the prevalence of influenza in symptomatic outpatient children peaked at 21% and stayed above 10% for ∼4 weeks. In contrast, in 2003–2004, influenza prevalence peaked at 60% and remained above 20% for ∼6 weeks. The positive predictive value of the rapid tests approached 80% when influenza prevalence was ≥15% but decreased to <70% when influenza prevalence was <10%.

CONCLUSIONS. Influenza prevalence varies between and within seasons. On the basis of our estimates, rapid tests are of limited use when prevalence is <10%. The appropriate interpretation of rapid influenza tests requires local influenza surveillance and timely communication of this information to the practitioners.
Office-Based Counseling for Unintentional Injury Prevention
Authors: Gardner H. Garry ,   and the Committee on Injury, Violence, and Poison Prevention
Published: January 2007

Unintentional injuries are the leading cause of death for children older than 1 year. Pediatricians should include unintentional injury prevention as a major component of anticipatory guidance for infants, children, and adolescents. The content of injury-prevention counseling varies for infants, preschool-aged children, school-aged children, and adolescents. This report provides guidance on the content of unintentional injury-prevention counseling for each of those age groups.
Prevention of Rotavirus Disease: Guidelines for Use of Rotavirus Vaccine
Authors:   Committee on Infectious Diseases
Published: January 2007

This Policy Statement was retired July 2010.

On February 3, 2006, a bovine-based pentavalent rotavirus vaccine (RotaTeq, Merck & Co Inc, Whitehouse Station, NJ) was licensed by the US Food and Drug Administration for use in infants in the United States. The American Academy of Pediatrics recommends routine immunization of infants with 3 doses of pentavalent rotavirus vaccine administered orally at 2, 4, and 6 months of age. The first dose should be administered between 6 and 12 weeks of age; immunization should not be initiated for infants older than 12 weeks of age. Subsequent doses should be administered at 4- to 10-week intervals, and all 3 doses of vaccine should be administered by 32 weeks of age. Pentavalent rotavirus vaccine can be coadministered with other childhood vaccines. Pentavalent rotavirus vaccine is contraindicated for infants with a serious allergic reaction to any vaccine component or to a previous dose of vaccine.
Can urbanization solve inter-sector water conflicts? Insight from a case study in Hebei Province, North China Plain
Authors: Kendy Eloise , Wang Jinxia , Molden David J. , Zheng Chunmiao , Liu Changming , Steenhuis Tammo S.
Published: January 2007

China, like many countries, is experiencing an unprecedented rate of urbanization. Urbanization is usually thought to intensify inter-sectoral water conflicts. In contrast, this paper considers urbanization as part of a viable solution to the problem. By evaluating water consumption, or depletion, in terms of actual evaporation and transpiration, as opposed to the amount withdrawn from water sources, this paper argues that urbanization has a positive role to play in lessening inter-sectoral water competition and in reversing groundwater declines. At the regional scale, urbanization can help achieve these goals by replacing some agricultural land use, particularly under two conditions: (1) both the industrial and agricultural sectors adopt water-saving technologies, and (2) urban wastewater and runoff are treated and reused directly in agriculture or indirectly through artificial recharge. Combined, the two conditions must result in a net decrease in water consumption at the regional scale. These points are illustrated with a case study of rural Luancheng County and adjacent industrialized Shijiazhuang City in Hebei Province. A water-balance approach provides a simple, quantitative framework for evaluating the potential for various land-use mosaics to stabilize groundwater levels.
Solid–solid reaction kinetics: Formation of tricalcium aluminate
Authors: Ghoroi Chinmay , Suresh A. K.
Published: January 2007

Tricalcium aluminate is an important constituent of Portland cement, apart from having other applications. It is formed by a solid–solid reaction between CaO and Al2O3, themselves formed by solid‐state decompositions of CaCO3 and Al(OH)3, respectively. There is no unanimity in the literature about the kinetic and mechanistic aspects of its formation. In this article we report experimental studies on this system with a view to identifying the reasons for these discrepancies and to present reproducible kinetic information under a well‐defined set of conditions. The experiments cover a temperature range of 1100–1300°C and use CaCO3 and Al(OH)3 gel powder as the starting materials. Reactions have been carried under a variety of conditions in an attempt to identify the experimental variables that influence the observed kinetics. The results show that mechanochemical activation can profoundly influence rates. The most reproducible and consistent results were obtained under conditions of good interparticle contact, with controlled pretreatment to define the physical structure of the reacting entity. Further, the results throw light on the sequential nature of the reaction and establish the nature of the intermediate phase. The data, when interpreted in the traditional manner, show consistent trends with the literature, but the deficiencies of such interpretation have been analyzed and the need for new models has been advanced. Because solid–solid reactions are generally less well understood than their fluid counterparts, our results argue in favor of a comprehensive modeling framework for such series reaction networks in the solid phase. © 2007 American Institute of Chemical Engineers AIChE J 2007
Dipping characteristics of layered silicates–natural rubber latex nanocomposites
Authors: Mathew Shera , Varghese Siby , Rajammal G. , Thomas P. C.
Published: January 2007

The dipping characteristics of prevulcanized natural rubber latex containing three different types of silicates (fluorohectorite, bentonite, and English Indian clay) were studied using a semiautomatic dipping machine. The effect of variation in the speed of immersion and withdrawal of the glass former, dwell time, and concentration of the coagulant, etc. on the thickness of the latex deposit were investigated. Characterization of the composites was done using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The viscosities of these compounds were measured using a Brookfield viscometer. The results of the studies showed that the deposit thickness depends on the withdrawal speed of the glass former, the concentration of the coagulant, dwell time, and the viscosity of the latex compound. Higher film thickness was noticed for the bentonite clay‐filled composites. This was believed to be due to the formation of clay network formation in the composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Lamellar and Three‐Dimensional Hybrid Compounds Formed by Cyclohexene‐ and Cyclohexanedicarboxylates of Pb, La, and Cd
Authors: Rao K. Prabhakara , Thirumurugan A. , Rao C. N. R.
Published: January 2007

To establish factors that determine the formation of three‐dimensional hybrid structures of metal dicarboxylates involving metal–oxygen–metal linkages, we have investigated metal dicarboxylates derived from 1,2‐cyclohexene as well as 1,2‐, 1,3‐, and 1,4‐cyclohexane dicarboxylic acids. Thus, we have synthesized a 1,2‐cyclohexenedicarboxylate of Cd, [Cd(1,2‐CHeDC)(H2O)] (I), a 1,2‐cyclohexanedicarboxylate of Pb, [Pb(1,2‐CHDC)] (II), and three 1,4‐cyclohexanedicarboxylates of La [La2(1,4‐CHDC)3(H2O)4] (III), [La3(1,4‐HCHDC)2(1,4‐CHDC)5(H2O)2]⋅H2O (IV) and [La2(1,4‐CHDC)3(H2O)]⋅2.5 H2O (V) under hydrothermal conditions and determined their structures. A mixed dicarboxylate involving both 1,3‐ and 1,4‐cyclohexenedicarboxylates of Pb, [Pb3O(1,3‐CHDC)(1,4‐CHDC)]⋅0.5 H2O (VI) and a 1,4‐cyclohexanedicarboxylate of Pb, [Pb6O2(1,4‐CHDC)3(1,4‐HCHDC)2], have also been synthesized and characterized. While the 1,2‐dicarboxylates have layered structures, the 1,4‐dicarboxylates and the mixed dicarboxylates possess three‐dimensional structures. Interestingly, both the 1,2 and 1,4‐dicarboxylates are true hybrid compounds composed of infinite M‐O‐M linkages. The equatorial–equatorial (e,e) conformation is adopted commonly in all these compounds, although less stable conformations are encountered occasionally. The formation of the layered and the three‐dimensional structures can be understood based on the relative disposition of the two carboxylic groups, the 1,4‐isomer favoring the three‐dimensional structure. Based on the results of the present study along with the available literature, we conclude that in order to obtain three‐dimensional hybrid structures with metal–oxygen–metal networks, it appears necessary to make use of the 1,4‐cyclohexanedicarboxylic acid.
Reactions of carbanions with 2,4‐dinitrofluorobenzene leading to stable heptatrienide moieties
Authors: Gololobov Yuri G. , Linchenko Olesya A. , Petrovskii Pavel V. , Starikova Zoija A. , Garbuzova Irina A.
Published: January 2007

Reactions of NCCH2COOMe 1a and CH2(CN)2 1b with 2,4‐dinitrofluorobenzene 2 at the presence of Et3 N result in deeply colored crystalline stable salts 4a,4b with anions that contain a system of conjugated bonds. Similar reaction of 2 with phosphorus‐containing zwitterion 6 bearing ethoxy‐ and cyano‐groups at the carbanion center is the first example of the reaction leading to the formation of P‐zwitterion 9 with a negatively charged heptatriene moiety. This reaction proceeds via a new route of decomposition of the intermediate σ‐complex 7 occurring with formation of ethylfluoroformate. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:108–115, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20267
Secondary metabolism of olive secoiridoids. New microcomponents detected in drupes by electrospray ionization and high‐resolution tandem mass spectrometry
Authors: Di Donna Leonardo , Mazzotti Fabio , Napoli Anna , Salerno Raffaele , Sajjad Ashif , Sindona Giovanni
Published: January 2007

Olive drupe tissues have been selected as a possible source of information about the secondary metabolism of oleaceae secoiridoids. The structures of a number of new microcomponents, detected and isolated by a combined high‐performance liquid chromatography (HPLC)‐fraction collector/ultraviolet electrospray ionization mass spectrometry (UV/ESI‐MS) apparatus, can be inferred from the data obtained by high‐resolution tandem mass spectrometry in a QqTOF instrument. Some of them (1, 2, 3 and 4) are closely correlated to oleuropein. Others, such as neo‐nuzhenide (5) and 2″‐hydroxyoleuropein (6), typical of other oleaceae families, have never been found in olive tissues. Copyright © 2007 John Wiley & Sons, Ltd.
The accuracy of first trimester ultrasound in the diagnosis of hydatidiform mole
Authors: Kirk E. , Papageorghiou A. T. , Condous G. , Bottomley C. , Bourne T.
Published: January 2007

Objective

Previous studies have examined ultrasound findings in histopathologically confirmed cases of hydatidiform mole. The aim of this study was to assess the first‐trimester ultrasonographic findings in all women suspected of having hydatidiform mole on ultrasound and those subsequently diagnosed with hydatidiform mole after histological examination of removed products of conception after surgical evacuation of the uterus. The aim was to obtain a true sensitivity and positive predictive value for ultrasound in the diagnosis of hydatidiform mole.

Methods

A retrospective analysis was performed of all cases of sonographically suspected hydatidiform mole and histologically proven hydatidiform mole presenting to the Early Pregnancy Unit of an inner city hospital over a 4‐year period. The sensitivity and positive predictive value (PPV) of ultrasound in the detection of histologically proven hydatidiform mole was calculated.

Results

The study group consisted of 90 women; 56 were suspected of having hydatidiform mole on ultrasound, and of these 27 (48%) had hydatidiform mole confirmed after histopathological examination of the products of conception, while no changes suggestive of hydatidiform mole were present in the other 29 cases. Overall, 61 women had hydatidiform mole confirmed on histology—41 (67%) partial hydatidiform moles (PHM) and 20 (33%) complete hydatidiform moles (CHM). The ultrasound findings in the 34 cases not suspected of hydatidiform mole were an empty sac in 8/34 (24%) women and a delayed miscarriage in the other 26/34 (76%). The overall sensitivity and positive predictive value for the ultrasound diagnosis of hydatidiform mole was 44% and 48%, respectively. For PHMs the respective values were 20% and 22% and for CHMs they were 95% and 40%.

Conclusion

Ultrasonography is more reliable for diagnosing CHMs than for PHMs. Overall, the sensitivity of ultrasound for accurately predicting hydatidiform mole is 44%, and one in two women with an abnormal scan will have the disease confirmed on histology. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
The value of measuring endometrial thickness and volume on transvaginal ultrasound scan for the diagnosis of incomplete miscarriage
Authors: Sawyer E. , Ofuasia E. , Ofili‐Yebovi D. , Helmy S. , Gonzalez J. , Jurkovic D.
Published: January 2007

Objective

To identify ultrasound measurements that are the best predictors of the presence of retained products of conception (RPOC) within the uterine cavity in women with clinical diagnosis of incomplete miscarriage.

Methods

This was a prospective observational study, set in a dedicated early pregnancy assessment unit in a London teaching hospital. Endometrial thickness and the volume of suspected retained products of conception were measured by transvaginal ultrasound scan preoperatively. Indications for surgical intervention were heavy vaginal bleeding or continuous bleeding lasting > 7 days. The main outcome measure was histological evidence of chorionic villi in surgical specimens.

Results

Among the patients, 109 (85%) had evidence of chorionic villi on histology, whilst decidua was only found in the remaining 19 (15%). There was no identifiable cut‐off for endometrial thickness or volume that could be used to differentiate between retained products of conception and decidua.

Conclusion

Measurements of endometrial thickness or volume on ultrasound scan are not good tests for diagnosing an incomplete miscarriage. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Direct numerical simulation of hypersonic turbulent boundary layers. Part 1. Initialization and comparison with experiments
Authors: MARTIN M. PINO
Published: January 2007

A systematic procedure for initializing supersonic and hypersonic turbulent boundary layers at controlled Mach number and Reynolds number conditions is described. The initialization is done by locally transforming a true direct numerical simulation flow field, and results in a nearly realistic initial magnitude of turbulent fluctuations, turbulence structure and energy distribution. The time scales necessary to forget the initial condition are studied. The experimental conditions of previous studies are simulated. The magnitude of velocity and temperature fluctuations, as well as the turbulent shear stresses given by the direct numerical simulations are in agreement with the experimental data.
Laminar and turbulent comparisons for channel flow and flow control
Authors: MARUSIC IVAN , JOSEPH D. D. , MAHESH KRISHNAN
Published: January 2007

A formula is derived that shows exactly how much the discrepancy between the volume flux in laminar and in turbulent flow at the same pressure gradient increases as the pressure gradient is increased. We compare laminar and turbulent flows in channels with and without flow control. For the related problem of a fixed bulk-Reynolds-number flow, we seek the theoretical lowest bound for skin-friction drag for control schemes that use surface blowing and suction with zero-net volume-flux addition. For one such case, using a crossflow approach, we show that sustained drag below that of the laminar-Poiseuille-flow case is not possible. For more general control strategies we derive a criterion for achieving sublaminar drag and use this to consider the implications for control strategy design and the limitations at high Reynolds numbers.
Dynamically driven phase transformations in heterogeneous materials. II. Applications including damage
Authors: Plohr JeeYeon N. , Clements B. E. , Addessio F. L.
Published: January 2007

A model, developed for heterogeneous materials undergoing dynamically driven phase transformations in its constituents, has been extended to include the evolution of damage. Damage is described by two mechanisms: interfacial debonding between the constituents and brittle failure micro-crack growth within the constituents. The analysis is applied to silicon carbide-titanium (SiC-Ti) unidirectional metal matrix composites that undergo the following phenomena: Ti has a yield stress of approximately 0.5 GPa and above a pressure of about 2 GPa undergoes a solid-solid phase transformation. The inelastic work from plastic dissipation contributes to the temperature and pressure rise in the Ti. SiC behaves elastically below a critical stress, above which it is damaged by microcrack growth. Finally, under tensile loading, the interface between Ti and SiC debonds according to an interfacial decohesion law. Each process is first examined independently in order to understand how its characteristic behavior is manifested in the stress-strain response of the composite. The complex interplay between loading states, viscoplasticity, damage, and solid-solid phase transformations is then studied at both the micromechanics and macromechanics levels.
Dynamics of the magnetization of single domain particles having triaxial anisotropy subjected to a uniform dc magnetic field
Authors: Ouari Bachir , Kalmykov Yury P.
Published: January 2007

Thermally induced relaxation of the magnetization of single domain ferromagnetic particles with triaxial (orthorhombic) anisotropy in the presence of a uniform external magnetic field H0 is considered in the context of Brown’s continuous diffusion model. Simple analytic equations, which allow one to describe qualitatively the field effects in the relaxation behavior of the system for wide ranges of the field strength and damping parameters are derived. It is shown that these formulas are in complete agreement with the exact matrix continued fraction solution of the infinite hierarchy of linear differential-recurrence equations for the statistical moments, which governs the magnetization dynamics of an individual particle (this hierarchy is derived by averaging the underlying stochastic Landau-Lifshitz-Gilbert equation over its realizations). It is also demonstrated that in strong fields the longitudinal relaxation of the magnetization is essentially modified by the contribution of the high-frequency “intrawell” modes to the relaxation process. This effect discovered for uniaxial particles by Coffey et al. [Phys. Rev. B 51, 15947 (1995)] is the natural consequence of the depletion of population of the shallow potential well. However, in contrast to uniaxial anisotropy, for orthorhombic crystals there is an inherent geometric dependence of the complex magnetic susceptibility and the relaxation time on the damping parameter α arising from the coupling of longitudinal and transverse relaxation modes.
The effect of van der Waals interaction modeling on the vibration characteristics of multiwalled carbon nanotubes
Authors: He X. Q. , Eisenberger M. , Liew K. M.
Published: January 2007

An elastic multiple shell model is used for the vibration analysis of multiwalled carbon nanotubes (MWCNTs). The van der Waals (vdW) interaction between any two layers of the MWCNT is modeled as the radius-dependent function. Based on the simplified Donnell shell equations, explicit formulas are obtained for the radial-dominated natural frequencies and mode shapes of double- and triple-walled carbon nanotubes. The natural frequencies are calculated for MWCNT with various radii and number of tubes. The numerical results show that the effect of vdW interaction on the torsionally and longitudinally dominated natural frequencies is very small and can be neglected, and the vdW interaction has only a small influence on the lowest radial-dominated natural frequency, but plays a significant role in the higher radial-dominated natural frequencies for various combinations of m (number of longitudinal) and n (number of circumferential) waves in the mode even for the MWCNTs of small innermost radius. Especially, due to the effect of vdW interaction, there exists a change over in the order of the modes, from radially dominated mode to longitudinally dominated mode, or from longitudinally dominated mode to torsionally dominated mode even when the innermost radius of the MWCNT is very small, indicating that the interlayer vdW interaction plays a significant role in the vibration of MWCNTs with small radius. The effect of the mode order on the natural frequencies of MWCNT is also examined in detail.
Demonstration of soot particle resizing in an ethylene flame by small angle x-ray scattering
Authors: Mitchell J. B. A. , Courbe J. , Florescu-Mitchell A. I. , di Stasio S. , Weiss T.
Published: January 2007

The size distribution of soot nanoparticles in an ethylene flame has been mapped in an in situ small angle x-ray scattering measurement at the European Synchrotron Radiation Facility. It has been seen that an abrupt size distribution change occurs at about a third of the flame’s visible height and this is believed to be due to the oxidation and dehydrogenation of the particles.
Electrocaloric and pyroelectric properties of 0.75Pb(Mg1∕3Nb2∕3)O3–0.25PbTiO3 single crystals
Authors: Sebald Gael , Seveyrat Laurence , Guyomar Daniel , Lebrun Laurent , Guiffard Benoit , Pruvost Sebastien
Published: January 2007

Pyroelectric and electrocaloric characterization has been determined for 0.75Pb(Mg1∕3Nb2∕3)O3–0.25PbTiO3 relaxor based single crystal and ceramic. Differential scanning calorimetry was used for measuring the electrocaloric response for different electric fields in the vicinity of the Curie temperature. For both ceramic and crystals the maximum activity is found to be around the transition temperature. On the other hand hysteresis loops for different temperatures were used to predict the electrocaloric effect with very good qualitative agreements with direct measurements. Pyroelectric coefficient is found to be much larger for ⟨111⟩ single crystals reaching 1300×10−6Cm−2K−1 whereas the ceramic reaches only 750×10−6Cm−2K−1. Higher pyroelectric coefficient and lower dielectric permittivity lead to outstanding figures of merits for sensors and energy harvesting, with a gain of 260% for voltage responsivity and more than 500% for energy harvesting. Although having a much larger pyroelectric activity, the electrocaloric effect is about the same for crystals and ceramics—around 0.40J∕g for 2.5kV∕mm electric field step. This result is interpreted by the decrease of the pyroelectric coefficient for high electric field. The electrocaloric activity is in fact limited by the saturation polarization and difference between Curie transition temperature and the working temperature. Those two parameters are very similar for crystals and ceramics. Single crystals are consequently very interesting materials in the framework of energy harvesting and sensor applications whereas no real improvement of performances can be expected for electrocaloric refrigeration devices.
Study of phase transition in homogeneous, rigid extended nematics and magnetic suspensions using an order-reduction method
Authors: Ji Guanghua , Wang Qi , Zhang Pingwen , Zhou Hong
Published: January 2007

We study the phase transition in rigid extended nematics and magnetic suspensions by solving the Smoluchowski equation for magnetically polarized rigid nematic polymers and suspensions in equilibrium, in which the molecular interaction is modeled by a dipolar and excluded volume potential. The equilibrium solution (or the probability distribution of the molecular distribution) is given by a Boltzmann distribution parametrized by the (first-order) polarity vector and the (second-order) nematic order tensor along with material parameters. We show that the polarity vector coincides with one of the principal axes of the nematic order tensor so that the equilibrium distribution can be reduced to a Boltzmann distribution parametrized by three scalar order parameters, i.e., a polar order parameter and two nematic order parameters, governed by three nonlinear algebraic-integral equations. This reduction in the degree of freedom from 8 (3 in the polarity vector and 5 in the nematic order tensor) to 3 significantly simplifies the solution procedure and allows one to conduct a complete analysis on bifurcation diagrams of the order parameters with respect to the material parameters. The stability of the equilibria is inferred from the second variation of the free energy density.
Red photoluminescence in praseodymium-doped titanate perovskite films epitaxially grown by pulsed laser deposition
Authors: Takashima Hiroshi , Ueda Kazushige , Itoh Mitsuru
Published: January 2007

Intense red photoluminescence (PL) under ultraviolet (UV) excitation was observed in epitaxially grown Pr-doped Ca0.6Sr0.4TiO3 perovskite films. The films were grown on SrTiO3 (100) substrates by pulsed laser deposition, and their epitaxial growth was confirmed by x-ray diffraction and reflected high-energy electron diffraction. The observed sharp PL peak centered at 610nm was assigned to the transition of Pr3+ ions from the D21 state to the H43 state. The PL intensity was markedly enhanced by postannealing treatments at 1000°C, above the film-growth temperature of 600 or 800°C. Because the excitation and absorption spectra are similar to each other, it was suggested that the UV energy absorbed by the host lattice was transferred to the Pr ions, resulting in the red luminescence.
Phase locking of a frequency agile laser
Authors: Crozatier Vincent , Gorju Guillaume , Bretenaker Fabien , Le Gouët Jean-Louis , Lorgeré Ivan , Gagnol Claude , Ducloux Eric
Published: January 2007

The authors report on the development and phase locking of a frequency agile laser. The use of a simple unbalanced Mach-Zehnder interferometer together with a wideband phase-locked loop permits to control very fast frequency chirps (up to 3GHz in 5μs) with an excellent precision (frequency error less than 100kHz). The servoloop could be applied to many tunable lasers.
Vertical AlGaN deep ultraviolet light emitting diode emitting at 322nm fabricated by the laser lift-off technique
Authors: Kawasaki Koji , Koike Choshiro , Aoyagi Yoshinobu , Takeuchi Misaichi
Published: January 2007

A vertical AlGaN deep ultraviolet (DUV) light emitting diode (LED) emitting at 322nm was fabfricated by the laser lift-off technique. The emission area extended to the entire electrode uniformly, and the current crowding was suppressed effectively in the devices. As a result, the differential conductance of the vertical LED was improved by a factor of 5 and the operation voltage was reduced to half, compared to that of the lateral LED. The self-heating effect was effectively suppressed even at high-current-density operation. The vertical structure in the high resistive AlGaN LED has potential application in high-power AlGaN DUV devices.
High-density, uniform InSb∕GaSb quantum dots emitting in the midinfrared region
Authors: Tasco V. , Deguffroy N. , Baranov A. N. , Tournié E. , Satpati B. , Trampert A. , Dunaevskii M. S. , Titkov A.
Published: January 2007

The authors have developed a multistep molecular-beam epitaxy growth technique which allows them to grow InSb quantum dots with high structural perfection and high density. This technique consists in the deposition at a very low temperature followed by a properly designed annealing step. Fully strained InSb∕GaSb quantum dots with a density exceeding 7×1010cm−2 and lateral sizes in the 20–30nm range have been obtained. Narrow photoluminescence emission is obtained around 3.5μm up to room temperature.
Influence of cohesive energy on unit cell volume of perovskite manganites La1−xMxMnO3
Authors: Tang G. D. , Hou D. L. , Li Z. Z. , Zhao X. , Qi W. H. , Liu S. P. , Zhao F. W.
Published: January 2007

Ionic size is considered to be an important factor influencing the unit cell volume of manganites with an ABO3 structure. For La1−xSrxMnO3, however, although the average effective ion radius of all cations taken together increases with increasing x, the unit cell volume decreases for x<0.5. In the case of La1−xNaxMnO3, the unit cell volume reaches a minimum when x=0.3. Up to now, no satisfactory explanation of these phenomena has been found. In this letter, an explanation based on the ionic cohesive energy with a small additional metallic cohesive energy is described.
Donizetti's Serious Operas
Authors: Dean Winton
Published: January 2007

Until recently Donizetti was not respectable enough for musicology. He was remembered for two or three comedies; yet he and Rossini both devoted their mature years almost entirely to serious opera. Of Donizetti's 70 stage works, a few of which are lost, exactly half belong to the opera seria class (that includes two French grand operas); three are early works on Classical subjects, nine are opere semiserie, and 23 are comedies or farces. But those figures do not give a true picture. In the first place, twelve of the comic operas but only one of the serious are in a single act. Second, if we take the end of 1828 as a dividing line—which is roughly when Donizetti reached maturity—we find that before that date he composed 29 operas, of which only six are serious, whereas after it he produced eight comedies (five in one act), four semiseria (one in one act), and 29 full-length serious operas. Clearly he regarded Romantic tragedy as his main line.