bluuebunny/crossref_metadata_2025 huggingface dataset:
Catheter‐tracking FOV MR fluoroscopy
Authors: Atalar Ergin , Kraitchman Dara L. , Carkhuff Bliss , Lesho Jeffery , Ocali Ogan , Solaiyappan Meiyappan , Guttman Michael A. , Charles Harry K.
Published: March 2007

Recent improvements in intravascular magnetic resonance imaging techniques mandate an accurate method of monitoring the introduction of MR catheter probes into the vessel of interest. For this purpose, a novel imaging protocol and a display method have been designed. First, a roadmap 3D image data set with standard pulse sequences is obtained using an external imaging coil. Subsequently, using very narrow rectangular‐FOV fast‐spoiled gradient recalled (SPGR), a movie of the percutaneous placement procedure of an MR catheter probe is acquired at a rate of 7.3 frames/second. In this protocol, the probe is used to transmit RF pulses and receive MR signal. A computer program was written for image unwrapping and for displaying the unwrapped movie frames on the roadmap image. In an alternative protocol, the movie frames in two projection angles were acquired in an interleaved fashion. Frames were unwrapped and combined with a 3D roadmap and displayed on a Silicon Graphics workstation equipped with stereovision goggles. Using these methods, percutaneous catheter placement in a phantom and a dog was examined. In conclusion, a new visualization technique for MR catheter placement is proposed. Combining this technique with high resolution intravascular MRI techniques may result in a very useful diagnostic tool for the evaluation of atherosclerosis and other vessel diseases.
Optimized visualization of vessels in contrast enhanced intracranial MR angiography
Authors: Parker Dennis L. , Goodrich K. Craig , Alexander Andrew L. , Buswell Henry R. , Blatter Duane D. , Tsuruda Jay S.
Published: March 2007

In this study, the problem of small vessel visualization in magnetic resonance angiography is addressed. The loss of vessel contrast due to slow flow‐related signal saturation can be compensated by the T1 reduction obtained from the use of an MR contrast agent, such as Gd‐DTPA. The vesselfbackground signal‐difference‐to‐noise ratio (SDNR) is shown to strongly depend on the imaging parameters, as well as on the time course of the blood T1 values obtained from the contrast injection. Specifically, it was found that vessel SDNR increases almost linearly with TR, if the sampling bandwidth is reduced proportionately.
Two‐dimensional multishot echo‐planar coronary MR angiography
Authors: Slavin Glenn S. , Riederer Stephen J. , Ehman Richard L.
Published: March 2007

This work presents a two‐dimensional (2D) multishot echo‐planar imaging (EPI) technique for magnetic resonance angiography (MRA) of individual coronary arteries in a 17‐heart‐beat breath‐hold. Conventional 2D and 3D segmented gradient‐echo (GRE) coronary MRA requires repetitive excitation of the same slice or slab within each cardiac cycle, which can result in reduced blood signal and in motion artifacts. Two‐dimensional multishot EPI can address these limitations by eliminating multiple excitations per cardiac cycle, using large flip‐angle excitations, markedly reducing the data acquisition window, and performing oblique multislice 2D imaging. The goal of this study was to assess the feasibility of breath‐hold 20 multishot EPI for multislice coronary MRA and to demonstrate its reliability by consistently acquiring high‐quality images of the coronary arteries in a series of 16 volunteers.
Design of practical T2‐selective RF excitation (TELEX) pulses
Authors: Sussman Marshall S. , Pauly John M. , Wright Graham A.
Published: March 2007

Traditional T2‐based imaging techniques are geared toward imaging long‐T2, species. Traditional techniques are, therefore, not optimal in clinical situations where the information of interest lies in the short‐T2 species. T2‐selective RF excitation (TELEX) is a technique for obtaining a T2‐based contrast that highlights short‐T2 values while suppressing long‐T2 values‐opposite to traditional T2 contrast. Previously, TELEX has been demonstrated qualitatively to highlight only very short‐T2 values (T2 = 0.001 s). When applied to longer T2 values (T2 ≈︁ 0.01 s), TELEX becomes sensitive to ΔBo non‐uniformities. This restricts its application to problems in which the T2 of interest is very short. In this study, TELEX is characterized quantitatively. Furthermore, a bandwidth broadening scheme is developed that reduces the ΔBo sensitivity of TELEX. This permits the technique to be applied to longer T2 values. The capabilities and limitations of a practical implementation of TELEX are discussed.
Integrated and interactive position tracking and imaging of interventional tools and internal devices using small fiducial receiver coils
Authors: Coutts Glyn A. , Gilderdale David J. , Chui Ming , Kasuboski Larry , Desouza Nandita M.
Published: March 2007

A method is described of tracking the position of a rigid device within an MR scanner and imaging with the image slice position determined by the current position of the device, such that the manipulation of the device can be achieved in a robust, interactive manner. The device can be either external or internal to the patient. The position tracking is performed by means of two or three small MR receiver coils attached to individual receiver channels. Each coil contains a small sample that acts as a fiducial (MR‐visible marker point). The imaging is performed by any suitable receiver coil attached to a further receive channel. This method has a large number of applications, both in the field of MR‐guided procedures and in MR imaging using endocavitary coils. In particular, two devices are described, the first being a device for MR‐guided biopsies and the second being one for dynamic endorectal imaging of the anal sphincter.
The MR tomograph as a sound generator: fMRI tool for the investigation of the auditory cortex
Authors: Bilecen Deuiz , Radü Ernst W. , Scheffler Klaus
Published: March 2007

An automatic fMRl protocol for the investigation of the human auditory cortex has been developed. For the activation of the auditory system, the scanner noise itself is the source of sound. Rapid switching of 6, gradients allows the generation of tones of defined frequencies and amplitude on a conventional scanner without hardware change. No additional device for sound generation or sound delivety is needed. The proposed technique allows functional MRI of the auditory cortex in a clinical routine session.
Perfusion imaging using FOCI RF pulses
Authors: Yongbi Martin N. , Branch Craig A. , Helpern Joseph A.
Published: March 2007

Pulsed arterial spin‐tagging techniques for perfusion measurements (e.g., echo planar MR imaging and signal targeting with alternating radiofrequency (EPISTAR), flow‐sensitive alternating inversion recovery (FAIR), quantitative imaging of perfusion using a single subtraction (QUIPPS), uninverted FAIR (UNFAIR)) generally use hyperbolic secant (HS) pulses for spin inversion. The performance of these techniques depends on the inversion efficiency, as well as the sharpness of the slice profiles. Frequency offset corrected inversion (FOCI) pulses, a recently proposed HS variant, can provide slice profiles with edges that can be up to 10 times sharper than those obtained with conventional HS pulses. In this communication, the implementation and application of the C–shape FOCI pulse for perfusion imaging in rat brain with the FAIR technique is summarized. Despite providing a more rectangular slice profile than a conventional HS pulse, it is demonstrated both theoretically and experimentally that the FAIR perfusion signal is not increased by using a FOCI tagging pulse. However, the use of a FOCI inversion pulse is shown to significantly minimize static signal subtraction errors that are common with conventional HS pulses. Finally, the suitability of the pulse for perfusion studies is demonstrated, in vivo, on rat brain.
Dynamic refinement and boundary contact forces in SPH with applications in fluid flow problems
Authors: Feldman J. , Bonet J.
Published: March 2007

This paper presents a general method for dynamic particle refinement in smoothed particle hydrodynamics (SPH). Candidate particles are split into several ‘daughter’ particles according to a given refinement pattern centred about the original particle. Through the solution of a non‐linear minimization problem the optimal mass distribution of the daughter particles is obtained so as to reduce the errors introduced to the underlying density field. This procedure necessarily conserves the mass of the system. Conservation of energy and momentum results are also discussed. Copyright © 2007 John Wiley & Sons, Ltd.
A substructured FE‐shell/XFE‐3D method for crack analysis in thin‐walled structures
Authors: Wyart E. , Coulon D. , Duflot M. , Pardoen T. , Remacle J.‐F. , Lani F.
Published: March 2007

Stress intensity factors in thin‐walled cracked structures are computed using a mixed‐dimensional finite element (FE) shell/extended finite element (XFE) 3D formulation. The present approach belongs to the family of ‘substructuring’ methods. The domain is decomposed into cracked and safe subdomains which are solved by the XFE‐code and the FE‐software, respectively. The XFE‐3D domain may contain cracks that do not necessarily join the top and bottom faces of the plate. The interface problem is solved using the finite element tearing and interconnecting method. Several validations are provided. Copyright © 2007 John Wiley & Sons, Ltd.
Recognition and management of drug‐induced blood disorders
Authors: Cox Anthony
Published: March 2007

Our series on serious ADRs focusses on rare but important drug reactions and how to recognise and avoid them. This article out lines how to identify drug‐ induced blood disorders and describes the drugs commonly implicated. Copyright © 2007 Wiley Interface Ltd
Diagnosis and treatment of urinary tract infection in children
Authors: Obi Ben , Sinha Manish
Published: March 2007

Our new series Prescribing in children gives practical advice for the successful management of childhood problems in general practice. Here, the authors discuss the methods of diagnosing urinary tract infection and highlight factors to consider prior to selecting antibiotic treatment. Copyright © 2007 Wiley Interface Ltd
Magnetic properties of Ce,Dy‐substituted yttrium iron garnet ferrite powders fabricated using a sol–gel method
Authors: Xu Haitao , Yang Hua
Published: March 2007

Y3–x –y Cex Dyy Fe5O12 (x = 0–0.1, y = 0–1.0) nanoparticles were fabricated by a sol–gel method. The crystalline structures and magnetic properties of the samples were investigated by X‐ray diffraction (XRD), scanning probe microscopy (SPM), X‐ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The XRD patterns of Y3–x –y Cex Dyy Fe5O12 have only peaks of the garnet structure and the mean size range from 42 to 60 nm. The particles' sizes observed for all the samples analyzed by SPM are in good agreement with these data from XRD. Results of VSM show that the saturation magnetization increases with increasing Ce content (x) and decreases with increasing Dy content (y) in a linear manner. The saturation magnetization increases with increasing particle size. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pycnogenol® reduces talc‐induced neoplastic transformation in human ovarian cell cultures
Authors: Buz'Zard Amber R. , Lau Benjamin H. S.
Published: March 2007

Talc and poor diet have been suggested to increase the risk of developing ovarian cancer; which can be reduced by a diet rich in fruit and vegetables. Talc is ubiquitous despite concern about its safety, role as a possible carcinogen and known ability to cause irritation and inflammation. It was recently shown that Pycnogenol® (Pyc; a proprietary mixture of water‐soluble bioflavonoids extracted from French maritime pine bark) was selectively toxic to established malignant ovarian germ cells. This study investigated talc‐induced carcinogenesis and Pyc‐induced chemoprevention. Normal human epithelial and granulosa ovarian cell lines and polymorphonuclear neutrophils (PMN) were treated with talc, or pretreated with Pyc then talc. Cell viability, reactive oxygen species (ROS) generation and neoplastic transformation by soft agar assay were measured. Talc increased proliferation, induced neoplastic transformation and increased ROS generation time‐dependently in the ovarian cells and dose‐dependently in the PMN. Pretreatment with Pyc inhibited the talc‐induced increase in proliferation, decreased the number of transformed colonies and decreased the ROS generation in the ovarian cells. The data suggest that talc may contribute to ovarian neoplastic transformation and Pyc reduced the talc‐induced transformation. Taken together, Pyc may prove to be a potent chemopreventative agent against ovarian carcinogenesis. Copyright © 2007 John Wiley & Sons, Ltd.
Potent in vitro cytotoxic and antioxidant activity of Careya arborea bark extracts
Authors: Senthilkumar Natesan , Badami Shrishailappa , Cherian Manju Mary , Hariharapura Raghu Chandrasekar
Published: March 2007

Careya arborea is used in traditional medicine for the treatment of tumors and other ailments. The successive chloroform and ethyl acetate extracts and crude 50% methanol extract exhibited potent cytotoxicity against cancerous RD, HEp‐2 and HeLa cell lines. They were found to be safe against the normal Vero cell line. The methanol and aqueous extracts possessed strong antioxidant activity against many oxidants in the in vitro antioxidant screening. The total phenol content of these extracts was found to be high. The results suggest strong cytotoxic and antioxidant properties and support the ethnomedical claims for the plant. Copyright © 2007 John Wiley & Sons, Ltd.
Differential growth inhibitory effects of W. somnifera root and E. officinalis fruits on CHO cells
Authors: Sumantran Venil N. , Boddul Sanjay , Koppikar Soumya J. , Dalvi Madhuri , Wele Asmita , Gaire Vishakha , Wagh Ulhas V.
Published: March 2007

The Chinese Hamster ovary (CHO) cell line is widely used for measuring drug cytotoxicity and resistance. Therefore, the effects of two major Ayurvedic drugs (W. somnifera root and E. officinalis fruits) on the short and long‐term growth of these cells were investigated. A standard 96‐well plate assay was used to measure short‐term growth. For assessment of long‐term growth, the colony formation assay (CFA) was used, which measures clonogenic potential. This assay is the best measure of the cytotoxicity of anticancer drugs and the radio‐sensitivity of tumor cells. As reported by others, the aqueous extracts of both herbal drugs were found to have short‐term growth inhibitory effects on CHO cells when added to cells at the time of cell plating. However, this is the first report showing that these two herbal drugs have significantly different effects on the long‐term growth of CHO cells. Thus, extracts of W. somnifera root, but not E. officinalis fruit, caused a reproducible, dose dependent, inhibition of colony formation of CHO cells. Copyright © 2007 John Wiley & Sons, Ltd.
Identification and properties of 2,5‐Dihydroxy‐4,3′‐di(β‐d‐glucopyranosyloxy)‐trans‐stilbene from Morus bombycis Koidzumi roots
Authors: Jin Ying‐Shan , Kim Min‐Kyeong , Heo Seong‐II , Han Woong , Wang Myeong‐Hyeon
Published: March 2007

2,5‐Dihydroxy‐4,3′‐di(β‐d‐glucopyranosyloxy)‐trans‐stilbene was identified from Morus bombycis Koidzumi roots. The 2,5‐dihydroxy‐4,3′‐di(β‐d‐glucopyranosyloxy)‐trans‐stilbene at a dose of 400–600 mg/kg had hepatoprotective activity comparable to the standard agent, silymarin. The biochemical assays were confirmed by histological observations showing that the 2,5‐dihydroxy‐4,3′‐di(β‐d‐glucopyranosyloxy)‐trans‐stilbene from Morus bombycis Koidzumi roots decreased cell ballooning in response to CCl4 treatment. These results demonstrate that the 2,5‐dihydroxy‐4,3′‐di(β‐d‐glucopyranosyloxy)‐trans‐stilbene component has a liver protective action against CCl4‐induced hepatotoxicity. Copyright © 2007 John Wiley & Sons, Ltd.
Preventative antiinflammatory effect of potamogetonan, a pectin from the common pondweed Potamogeton natans L.
Authors: Popov Sergey V. , Popova Galina Yu. , Paderin Nikita M. , Koval Olga A. , Ovodova Raisa G. , Ovodov Yury S.
Published: March 2007

The pectic polysaccharide named potamogetonan (PN) was obtained using extraction of the leaves and stems of the common pondweed Potamogeton natans L. by an aqueous ammonium oxalate. The purified potamogetonan PN‐300 was obtained using membrane ultrafiltration of PN and proved to be pectin with a molecular weight of 300 kDa. The capacity of potamogetonan PN‐300 to prevent inflammation was assessed using a carrageenan paw edema test in mice. Oral administration of PN‐300 24 h prior to induction of inflammation was found to reduce edema formation in a dose‐related manner. The maximal effect of PN‐300 was observed at 1 h after carrageenan injection (60% reduction of footpad swelling) and was comparable to that of indomethacin. The delayed edema (5 h) was less affected by pre‐administration of PN‐300 (33% reduction). PN‐300 was found to improve the survival of mice subjected to a lethal dose of LPS. The anti‐endotoxemic effect of PN‐300 was shown to be mediated by decreased TNF‐α and IL‐1β and increased IL‐10 production.

Thus, a pectin named potamogetonan PN‐300 was isolated from P. natans and was shown to possess a preventive antiinflammatory effect following oral administration. Copyright © 2007 John Wiley & Sons, Ltd.
Screening seeds of some Scottish plants for free radical scavenging activity
Authors: Kumarasamy Yashodharan , Byres Maureen , Cox Philip J. , Jaspars Marcel , Nahar Lutfun , Sarker Satyajit D.
Published: March 2007

From a consideration of ethnobotanical and taxonomic information, seeds of 45 Scottish plant species encompassing 23 different families were obtained from authentic seed suppliers. The n‐hexane, dichloromethane (DCM) and methanol (MeOH) extracts were assessed, both qualitatively and quantitatively, for free radical scavenging activity in the DPPH assay. The MeOH extracts of 37 species exhibited low to high levels of free radical scavenging activity (RC50 values ranging from 2.00 to 4.7 × 10−4 mg/mL), and Alliaria petiolata, Prunus padus and Prunus spinosa were the most potent antioxidant extracts. The DCM extracts of 17 species showed similar levels of activity, and among those, Prunus padus and Prunus spinosa extracts were the most active with RC50 values of 2.5 × 10−4 and 5.0 × 10−4 mg/mL, respectively. The n‐hexane extracts were much less active than the MeOH and DCM extracts, and 17 species, with the exception of Glechoma hederacea (RC50 = 1.94 × 10−4) displayed low to moderate levels of free radical scavenging property (RC50 values ranging from 2.00 to 8.7 × 10−3 mg/mL). Copyright © 2007 John Wiley & Sons, Ltd.
Drug–drug interaction prediction: a Bayesian meta‐analysis approach
Authors: Li Lang , Yu Menggang , Chin Raymond , Lucksiri Aroonrut , Flockhart David A. , Hall Stephen D.
Published: March 2007

In drug–drug interaction (DDI) research, a two drug interaction is usually predicted by individual drug pharmacokinetics (PK). Although subject‐specific drug concentration data from clinical PK studies on inhibitor/inducer or substrate's PK are not usually published, sample mean plasma drug concentrations and their standard deviations have been routinely reported. In this paper, an innovative DDI prediction method based on a three‐level hierarchical Bayesian meta‐analysis model is developed. The first level model is a study‐specific sample mean model; the second level model is a random effect model connecting different PK studies; and all priors of PK parameters are specified in the third level model. A Monte Carlo Markov chain (MCMC) PK parameter estimation procedure is developed, and DDI prediction for a future study is conducted based on the PK models of two drugs and posterior distributions of the PK parameters. The performance of Bayesian meta‐analysis in DDI prediction is demonstrated through a ketoconazole–midazolam example. The biases of DDI prediction are evaluated through statistical simulation studies. The DDI marker, ratio of area under the concentration curves, is predicted with little bias (less than 5 per cent), and its 90 per cent credible interval coverage rate is close to the nominal level. Sensitivity analysis is conducted to justify prior distribution selections. Copyright © 2007 John Wiley & Sons, Ltd.
Item reduction in a scale for screening
Authors: Liu Xinhua , Jin Zhezhen
Published: March 2007

This paper presents a non‐parametric approach for the selection of items in a scale for screening, with the score defined as the sum of item response indicators. Without specifying parametric models for binary classification probabilities, the proposed item selection method evaluates the change in classification accuracy due to adding or deleting one item for a scale with k items. It first removes least useful items from the scale and then uses a forward stepwise selection procedure to the remaining items to identify a subset of items for a reduced scale. The reduced scale usually retains or improves classification accuracy compared to the full scale. The variation in items selected can be assessed with bootstrap samples. In a simulation study, the proposed procedure shows a fairly good finite sample performance. The method is illustrated with a data set on patients with and without high risk of developing Alzheimer's disease who were administered a 40‐item test of olfactory function. Copyright © 2007 John Wiley & Sons, Ltd.
Wilcoxon‐based group sequential designs for comparison of areas under two correlated ROC curves
Authors: Zhou Xiao‐Hua , Li Sierra M. , Gatsonis Constantine A.
Published: March 2007

Clinical studies to evaluate the relative accuracies of two diagnostic modalities via their receiver operating characteristic (ROC) curves are currently conducted using fixed sample designs: cases are accrued until a predetermined sample size is achieved and, at that point, the areas under the ROC curves are computed and compared (Radiology 1982; 143:29–36; Radiology 1983; 148:839–843). In prospective ROC studies (Radiology 1990; 175:571–575), participants are recruited from a clinically defined cohort and diagnostic test information is obtained and interpreted in advance of ascertaining the definitive proof of diagnosis (‘gold standard’). In retrospective studies, cases are selected from a set of patient records and their diagnostic tests are interpreted without knowledge of the ‘gold standard’. The conduct of ROC studies requires considerable effort and resources, particularly for the collection of ‘gold standard’ information. Thus, it is highly desirable to search for designs which are more efficient than using a fixed sample.

In this paper, we discuss the formulation and application of group sequential designs (GSDs) to comparative ROC studies based on non‐parametric Wilcoxon estimators of the area under the ROC curves. The approach is applicable to comparisons of ROC curve areas of two tests measured on either continuous or ordinal scales on same cases (‘paired’ designs) with one reader. The adoption of GSDs may lead to substantial savings in the number of required cases, thus resulting in both time and resource use efficiency. Copyright © 2007 John Wiley & Sons, Ltd.
An investigation of two multivariate permutation methods for controlling the false discovery proportion
Authors: Korn Edward L. , Li Ming‐Chung , McShane Lisa M. , Simon Richard
Published: March 2007

Identifying genes that are differentially expressed between classes of samples is an important objective of many microarray experiments. Because of the thousands of genes typically considered, there is a tension between identifying as many of the truly differentially expressed genes as possible, but not too many genes that are not really differentially expressed (false discoveries). Controlling the proportion of identified genes that are false discoveries, the false discovery proportion (FDP), is a goal of interest. In this paper, two multivariate permutation methods are investigated for controlling the FDP. One is based on a multivariate permutation testing (MPT) method that probabilistically controls the number of false discoveries, and the other is based on the Significance Analysis of Microarrays (SAM) procedure that provides an estimate of the FDP. Both methods account for the correlations among the genes. We find the ability of the methods to control the proportion of false discoveries varies substantially depending on the implementation characteristics. For example, for both methods one can proceed from the most significant gene to the least significant gene until the estimated FDP is just above the targeted level (‘top‐down’ approach), or from the least significant gene to the most significant gene until the estimated FDP is just below the targeted level (‘bottom‐up’ approach). We find that the top‐down MPT‐based method probabilistically controls the FDP, whereas our implementation of the top‐down SAM‐based method does not. Bottom‐up MPT‐based or SAM‐based methods can result in poor control of the FDP. Published in 2007 by John Wiley & Sons, Ltd.
Abrasion and edge fracture resistance estimation of hard materials by tribotesting method
Authors: Scieszka S.F.
Published: March 2007

The use of tools manufactured from hard materials is limited by their fracture toughness and there is a need for research aimed at increasing toughness without sacrificing good wear resistance. To aid in this objective, a simple and reliable integrated tribotesting method is needed in which a combined action involving both fracture and abrasion occurs. One such method currently developed is presented in this paper. The method is based on the concept of edge chipping during the initial transition stage of abrasion wear, which is controlled by a brittle fracture process. The empirical relationship between mass loss as a result of edge chipping during the initial transitional stage of abrasive wear and fracture toughness is presented in the form of formulae. Copyright © 2007 John Wiley & Sons, Ltd.
Modelling analysis of transient stability simulation with high penetration of grid‐connected wind farms of DFIG type
Authors: Shi Libao , Xu Zheng , Hao Jin , Ni Yixin
Published: March 2007

This paper shows a model of a doubly fed induction generator (DFIG) including a simplified model of a wind turbine for the purpose of transient stability analysis of large‐scale power systems with great wind farms penetration. The wind turbine model and the DFIG model are systematically deducted in this paper. Specially, the improved model of rotor‐side converter and the simplified grid‐side converter model are considered in our work. The corresponding machine–network interface solution based on the synchronously rotating common x‐y reference frame is elaborately issued in this paper. Furthermore, a method is proposed to calculate the DFIG initial conditions as well. A simplified model of the turbine is used excluding among other components the pitch control. Copyright © 2007 John Wiley & Sons, Ltd.
Laparoscopic versus Open Appendectomy in Children: A Retrospective Comparative Study of 2,332 Cases
Authors: Esposito Ciro , Borzi Peter , Valla Jean Stephane , Mekki Monghi , Nouri Abdelatif , Becmeur Francois , Allal Hossein , Settimi Alessandro , Shier Felix , Sabin MiguelAntonio Gonzales , Mastroianni Luciano
Published: March 2007

Aim

The laparoscopic treatment of paediatric appendicitis remains controversial, especially in the presence of complications. This study evaluated the outcomes of open appendectomy (OA) and laparoscopic appendectomy (LA) by analysing the data from a multicentre study.

Methods

The authors retrospectively reviewed a series of 2,332 appendectomies (1,506 LA and 826 OA) performed in children and adolescents (median age 8 years) in 9 different centres of paediatric surgery. For the patients operated using laparoscopy, an IN procedure was employed in 921 (61.2%), an OUT procedure in 571 (37.9%) and a MIXED procedure in 14 (0.9%). In the open surgery, a McBurney incision was adopted in 795 patients (96.4%).

Results

Median duration of surgery was 40 minutes for LA and 45 minutes for OA. Median hospital stay was 3 days (LA) and 4.3 days (OA) in case of simple appendicitis and 5.2 days (LA) and 8.3 days (OA) in case of peritonitis. Complications were recorded in 124 LA cases (8.2%) and 65 OA cases (7.9%). The conversion rate in laparoscopy was only 1.6% (25 cases). The statistical analysis was performed using the Mann–Whitney test, and the main significant difference that emerged was the length of hospital stay, which was in favour of laparoscopy compared with open surgery (P < 0.0001).

Conclusions

We conclude that in clinical settings where laparoscopic surgical expertise and equipment are available and affordable, LA seems to be an effective and safe alternative to OA. Three out 9 centres participating in our survey perform LA in all patients with a suspicion of appendicitis. Our study shows that laparoscopy significantly reduces hospital stay in case of appendicitis and peritonitis and presents an extremely low conversion rate (1.6%) to open surgery. Laparoscopic transumbilical appendectomy (37.9%) in our series seems to be a simple option, even for less‐skilled laparoscopic surgeons.
A peculiar relationship between genetic diversity and adaptability in invasive exotic species: bluegill sunfish as a model species
Authors: Yonekura Ryuji , Kawamura Kouichi , Uchii Kimiko
Published: March 2007

A peculiar relationship exists between population genetics and invasion biology. Introduced populations often suffer a depletion of genetic variation, but they can persist and adapt to new environments. Here, we show that this relationship is observed in bluegill sunfish (Lepomis macrochirus), an invasive exotic fish in Japan. Genetic analysis using selectively neutral genetic markers reconfirmed that the bluegill introduced into Japan from the United States in 1960 had a single origin with only 15 founders. The analysis also shows that in the process of range expansion, the introduced bluegills experienced severe depletion of genetic diversity due to the founder effect and/or genetic drift. Despite such a decline in genetic diversity, the bluegill populations exhibited a divergent feeding morphology in response to the colonized environments. Such a morphological divergence can facilitate prey exploitation, thereby causing a greater negative impact on native prey resources. Further, in a trophically polymorphic bluegill population in Lake Biwa, physiological characteristics and genetic structures of the intestinal bacterial communities were associated with the difference in diet among the trophic morphs in the host bluegill population. This empirical evidence suggests that despite the severe decline in genetic diversity, the introduced bluegill populations rapidly adapted to the new environment and formed diverse functional relationships with the native bacterial community. Thus, these findings suggest that genetic variation at selectively neutral markers does not always predict adaptability and invasiveness in introduced populations.
Levels of Lipid Peroxidation in Human Plasma and Erythrocytes: Comparison between Fatty Acids and Cholesterol
Authors: Yoshida Yasukazu , Saito Yoshiro , Hayakawa Mieko , Habuchi Yoko , Imai Yasuharu , Sawai Yoshiyuki , Niki Etsuo
Published: March 2007

Lipid peroxidation has gained renewed attention with increasing evidence showing its biological role in producing toxic compounds and cellular signaling mediators. The assessment of lipid peroxidation levels in vivo is difficult partly because lipids are oxidized by different oxidants by different mechanisms to give versatile types of products, which may undergo metabolism and secondary reactions. In the present study, total hydroxyoctadecadienoic acids (tHODE) and 7α‐ and 7β‐hydroxycholesterol (t7‐OHCh) from 44 healthy human subjects were assessed as biomarkers after reduction with sodium borohydride followed by saponification with potassium hydroxide comparing with the prevailing standard 8‐isoprostaglandin F2α (t8‐iso‐PGF2α). The average concentrations of tHODE, total 8‐isoprostaglandin F2α (t8‐iso‐PGF2α), t7α‐OHCh, and t7β‐OHCh were 203, 0.727, 87.1, and 156 nmol/l plasma and 1,917, 12.8, 1,372, and 3,854 nmol/l packed erythrocytes, respectively. The ratios of tHODE and t7‐OHCh to the parent substrates were 194 and 3,519 μmol tHODE/mol linoleates and 40.9 and 686 μmol t7‐OHCh/mol cholesterol in plasma and erythrocytes, respectively. It was found that (1) t7‐OHCh in blood was unexpectedly high, as high as or even higher than tHODE, (2) the amounts of tHODE was more than 100 fold higher than t8‐iso‐PGF2α (3) the level of lipid oxidation products in erythrocytes was higher than that in plasma, and (4) lipid peroxidation products level tended to increase while antioxidant level decrease with age. These products may be used as potential biomarker for assessment of lipid peroxidation and oxidative stress in vivo.
Adolescent expectations and desires about marriage and parenthood
Authors: Plotnick Robert D.
Published: March 2007

Using data collected in 2000 on a racially and ethnically diverse sample of high school seniors, this study analyzes adolescents’ expectations and desires about marriage and parenthood, including unwed parenthood. The conceptual framework combines family context, opportunity cost, and social–psychological perspectives. Each perspective receives empirical support. Race, ethnicity, gender, parental education, and parental expectations for their child's education show significant relationships with expectations and desires about marriage and parenthood. Adolescents with higher opportunity costs, as indicated by better grades and higher expectations for their schooling, expect and desire to marry and have children at older ages. The relationships between parental education and parental expectations for their child's education and the outcomes are largely mediated through opportunity costs. Significant relationships between locus of control and the outcomes provide empirical support for the social–psychological element of the framework.
Crystal structure of intracellular family 1 β‐glucosidase BGL1A from the basidiomycete Phanerochaete chrysosporium
Authors: Nijikken Yuri , Tsukada Takeshi , Igarashi Kiyohiko , Samejima Masahiro , Wakagi Takayoshi , Shoun Hirofumi , Fushinobu Shinya
Published: March 2007

The white‐rot fungus Phanerochaete chrysosporium has two intracellular β‐glucosidases (BGL1A and BGL1B) belonging to glycoside hydrolase (GH) family 1. BGL1B effectively hydrolyzes cellobiose and cellobionolactone, but BGL1A does not. We have determined the crystal structure of BGL1A in substrate‐free and gluconolactone complexed forms. The overall structure and the characteristic of subsite −1 (glycone site) were similar to those of other known GH1 enzymes. The loop regions covering on the (β/α)8 barrel was significantly deviated, and they form a unique subsite +1 (aglycone site) of BGL1A.
Cooperation of group 2 σ factors, SigD and SigE for light‐induced transcription in the cyanobacterium Synechocystis sp. PCC 6803
Authors: Yoshimura Tsutomu , Imamura Sousuke , Tanaka Kan , Shirai Makoto , Asayama Munehiko
Published: March 2007

A light‐inducible σ factor of RNA polymerase, SigD, can contributes to the light‐induced transcription of psbA in the cyanobacterium Synechocystis sp. PCC 6803. Here, another light‐induced σ factor, SigE, was characterized together with SigD. Results indicated that SigE also contributes to light‐induced transcription on the cpcBACD, psbA, petBD and psaAB promoters whose potential sequences are of the Escherichia coli σ70‐type. SigD and SigE interfere with each other's expression. A rhythmic expression, in which the periodic peak of SigE exhibits a 24‐h interval according to the upcoming night, was observed at the protein level. The cooperation of group 2 σ factors, SigD and SigE, for light‐induced transcription was discussed.
Cervicothoracic goitre: an anatomical or radiological definition? Report of 223 surgical cases
Authors: Page C , Strunski V
Published: March 2007

Objectives:

To analyse and compare chest radiographs and cervicothoracic computed tomography scans taken prior to thyroid surgery, in order to locate and predict thoracic extension of substernal goitres.

Method:

This eight-year, retrospective study included 223 patients who had undergone total thyroidectomy for benign, substernal, multinodular goitres. Chest radiographs and computed tomography scans were reviewed by two physicians (a senior ENT surgeon and a senior radiologist).

Results:

The most frequent mode of extension was anterior or prevascular, seen in 76 per cent of cases, especially on the left side. Fifty-nine per cent of goitres did not reach the aortic arch and 11 per cent extended beyond the aortic arch. A cervical surgical approach was performed in approximately 99 per cent of cases.

Discussion:

Thorough examination of computed tomography scans is essential in order to identify and classify substernal goitres and to decide the best surgical procedure. A cervical surgical procedure is almost always sufficient and safe for the surgical management of substernal goitres.

Conclusion:

Computed tomography appears to be the best imaging modality for identifying and characterising substernal goitres. Surgical management is almost always via a cervical approach and does not differ from that used for benign cervical goitres. In the future, magnetic resonance imaging may be used; its results would need to be compared with those of computed tomography.
Changing Media, Changing Foreign Policy in China
Authors: SHIRK SUSAN L.
Published: March 2007

China has undergone a media revolution that has transformed the domestic context for making foreign policy as well as domestic policy. The commercialization of the mass media has changed the way leaders and publics interact in the process of making foreign policy. As they compete with one another, the new media naturally try to appeal to the tastes of their potential audiences. Editors make choices about which stories to cover based on their judgments about which ones will resonate best with audiences. In China today, that means a lot of stories about Japan, Taiwan, and the United States, the topics that are the objects of Chinese popular nationalism. The publicity given these topics makes them domestic political issues because they are potential focal points for elite dis-agreement and mass collective action, and thereby constrains the way China' leaders and diplomats deal with them. Even relatively minor events involving China' relations with Japan, Taiwan, or the United States become big news, and therefore relations with these three governments must be carefully handled by the politicians in the Communist Party Politburo Standing Committee. Because of the Internet, it is impossible for Party censors to screen out news from Japan, Taiwan or the United States that might upset the public. Common knowledge of such news forces officials to react to every slight, no matter how small. Foreign policy makers feel especially constrained by nationalist public opinion when it comes to its diplomacy with Japan. Media marketization and the Internet have helped make Japan China' most emotionally charged international relationship.
How Junichiro Koizumi seized the leadership of Japan's Liberal Democratic Party
Authors: KABASHIMA IKUO , STEEL GILL
Published: March 2007

In this paper, we examine some of the ways in which Koizumi Junichiro took advantage of changes in television news to win the 2001 Liberal Democratic Party (LDP) presidential election and become prime minister of Japan. Koizumi adopted a strategy of political populism to increase his exposure in the media and develop a public reputation. Changes in the LDP selection procedure, in combination with long-term social and economic change and political reform, meant that the media mattered more to his campaign than had previously been the case. We use data from the Japan Election Study II (JES II) to show that the effects of Koizumi' media-driven popularity and style of politics reversed the LDP' electoral fortunes in the Upper House Election in 2001.
Soft News and Foreign Policy: How Expanding the Audience Changes the Policies
Authors: BAUM MATTHEW A.
Published: March 2007

Since the 1980s, the mass media have changed the way they cover major political stories, like foreign policy crises. As a consequence, what the public learns about these events has changed. More media outlets cover major events than in the past, including the entertainment-oriented soft news media. When they do cover a political story, soft news outlets focus more on “human drama” than traditional news media – especially the character and motivations of decision-makers, as well as individual stories of heroism or tragedy – and less on the political or strategic context, or substantive nuances, of policy debates. Many Americans who previously ignored most political news now attend to some information about major political events, like wars, via the soft news media. These changes have important implications for democratic politics. Most importantly, a large number of particularly persuadable potential voters are now tuning in to politics via soft news outlets. This gives politicians an incentive to develop strategies for reaching out to them. Such individuals care less about the nuances of policy and more about the personality of leaders and any sensational human drama that a policy, like a war, entails. Soft news consumers care less about geopolitics than about body bags. Politicians who want their votes are therefore likely to emphasize body bags more than geopolitics. In short, the “new” media environment changes both the style and substance of politics in democracies.
Funktionelle Neuroplastizität bei zwei Jugendlichen mit ausgeprägten frühkindlichen strukturellen Hirnschädigungen
Authors: Zotter Sibylle , Haberlandt Edda , Gottwald Thaddäus , Kaufmann Liane
Published: March 2007

Zusammenfassung. Ziel der Studie war die detaillierte neurokognitive Untersuchung der funktionellen Neuroplastizität bei zwei 17-jährigen Mädchen, welche trotz großer posteriorer Substanzdefekte gute Schulleistungen und unauffälliges Verhalten aufwiesen. Unsere Ergebnisse zeigen, dass die neuropsychologischen Beeinträchtigungen nach frühkindlich erworbenen Substanzdefekten zwar gering, aber spezifisch sind. Relativ zu 10 gesunden Kontrollpersonen waren bei TB eine reduzierte verbale Lernleistung, jedoch gute sprachliche Leistungen feststellbar. MG demonstrierte defizitäre visuell-räumliche Fähigkeiten und zusätzlich - überraschenderweise - eine reduzierte verbale sowie nonverbale Merkfähigkeit. Insgesamt weisen die Ergebnisse darauf hin, dass die Mechanismen der neurofunktionellen Plastizität nicht auf Sprache und visuo-konstruktive Prozesse beschränkt sind, sondern sich auch in anderen kognitiven Domänen (z. B. Lesefertigkeiten und Merkfähigkeit) manifestieren können.
Neuropsychologische Beeinträchtigungen und kognitive Verarbeitung von Essensreizen bei Anorexia nervosa
Authors: Santel Stephanie , Münte Thomas F. , Krauel Kerstin , Rotte Michael , Baving Lioba
Published: March 2007

Zusammenfassung. Essstörungen stellen eine wichtige psychiatrische Behandlungsindikation dar. Es ist bekannt, dass bei diesen Erkrankungen auch klinisch relevante kognitive Defizite und Auffälligkeiten in der Informationsverarbeitung bestehen, die im Alltag der PatientInnen zu Beeinträchtigungen führen. Insbesondere im Hinblick auf die schwierige und langwierige Behandlung und hohen Rückfallquoten dieser Patientengruppe ist die Berücksichtigung dieser kognitiven Besonderheiten in der Therapie von Essstörungen wichtig. Der vorliegende Artikel beschreibt neurokognitive Auffälligkeiten bei Anorexia nervosa (AN) in verschiedenen relevanten Funktionsbereichen. Im zweiten Teil der Arbeit werden aktuelle Verhaltens- und Bildgebungsstudien zur Verarbeitung von nahrungsrelevanten Stimuli dargestellt.
Momentum Effects in Discussions on Intellective Tasks: Comparing Informed and Non-Informed Groups
Authors: Hansmann Ralf , Crott Helmut W. , Scholz Roland W.
Published: March 2007

A probabilistic model of opinion change (PCD model, Crott, Werner, & Hoffmann, 1996 ) was applied to analyze the opinion formation process in five-person group discussions concerning intellective tasks. Control groups performed conventional face-to-face discussions, whereas an informational intervention (INFO) was applied in the experimental condition. Analyses performed in line with the PCD model examined the attraction of the correct answer, the size of the subgroups favoring each answer alternative, and a dynamic factor accounting for the possibility that, immediately subsequent to an individual’s opinion change towards a particular alternative, the probability of additional opinion changes to that alternative is dynamically increased. In both conditions the model variants including the dynamic factor were able to adequately describe opinion formation. A stronger attracting influence of the correct answer was observed in the INFO condition compared to the control condition.
Wayfinding Behavior and Spatial Knowledge of Adults and Children in a Virtual Environment: The Role of the Environmental Structure
Authors: Jansen-Osmann Petra , Schmid Juliane , Heil Martin
Published: March 2007

This study investigated the effect of regularity in environmental structure on wayfinding behavior and spatial knowledge. A total of 60 participants (7- to 8-year-olds, 11- to12-year-olds, and adults) performed self-determined movements in a desktop virtual environment. In almost all measurements of wayfinding performance and spatial knowledge an overall developmental progress from younger children to adults was found. In contrast, exploration behavior did not differ between adults and children Furthermore, the environmental structure tended to influence only the wayfinding performance of younger children, but did not have any effect on the exploration behavior and the spatial knowledge of children or adults. This outcome supports the idea of a dissociation between exploration behavior, wayfinding performance and spatial knowledge as distinct aspects of spatial cognition.
Welche Lebensfertigkeiten fördert ein suchtpräventives Lebenskompetenzprogramm?
Authors: Bühler Anneke , Schröder Elke , Silbereisen Rainer K.
Published: March 2007

Zusammenfassung. Lebenskompetenzprogramme (LKP) zählen zu den effektivsten Einzelbausteinen der schulischen Suchtprävention. Trotz vieler Evaluationsstudien liegen kaum Überprüfungen des Interventionsmodells vor. Dies ergäbe aber evidenz-basierte Hinweise auf die Verbesserung der Maßnahmen. In der vorliegenden quasi-experimentellen Interventionsstudie wurde der Ansatz verfolgt, LKP verhaltensbezogener zu evaluieren und zunächst zu überprüfen, ob die trainierten Fertigkeiten bei den Programmteilnehmern tatsächlich Anwendung finden. Dazu wurden an einer Stichprobe mit 753 Fünftklässlern und einer randomisierten Teilstichprobe mit 52 Schülern der Einfluss eines suchtpräventiven Lebenskompetenzprogramms auf die von der WHO (1994) definierten Lebensfertigkeiten längsschnittlich mittels quantitativer und qualitativer Erhebungsverfahren untersucht. Die teilnehmenden Schüler und Schülerinnen des LKP verzeichneten gegenüber einer Kontrollgruppe einen Zuwachs an Wissen über Lebensfertigkeiten (z.B. Problemlösestrategien und Kommunikationsfertigkeiten) und berichteten über eine häufigere Anwendung in Alltagssituationen. Allerdings sind die Effektgrößen sehr klein. Die Ergebnisse liefern Ansatzpunkte, wie die Wirksamkeit der Lebenskompetenzprogramme zukünftig veränderungssensibler, verhaltensbezogener und interventionsorientierter erfasst werden kann, um sie empirisch begründet zu verbessern. Es wird angeregt, verstärkt Lebensfertigkeiten als potenzielle Mediatoren in die Analyse der Wirkmechanismen von LKP einzubeziehen.