bluuebunny/crossref_metadata_2025 huggingface dataset:
Representational Blending in Human Conditional Learning: Implications for Associative Theory
Authors: Hodder K. I. , George D. N. , Killcross A. S. , Honey R. C.
Published: May 2004

In two experiments, participants were presented with pictures of different foods (A, B, C, D, X,) and learned which combinations resulted in an allergic reaction in a fictitious patient, MrX. In Problem 1, when Aor B (but not Cor D) was combined with food Xan allergic reaction occurred, and when C or D(but not A or B) was combined with Y an allergic reaction occurred. In Experiment 1, participants also received Problem 2 in which A, B, C, and Dinteracted with foods V and Weither in the same way as X and Y, respectively, or in a different way. Participants performed more proficiently in the former than in the latter condition. In Experiment 2, after training on Problem 1, participants judged whether or not novel combinations of foods (e.g., AB, CD, AD, CB) would cause an allergic reaction in MrX. They were no more likely to indicate that ABor CD would cause an allergic reaction than AD or CB, but made their judgements more rapidly and with greater confidence on AB and CDtrials than on ADand CB trials. These results (1) indicate that shared representations come to be addressed by the components of similar compounds (e.g., AX and BX) that have predicted the same outcome (an allergic reaction), and (2) are inconsistent with standard, associative theories of learning, but (3) are consistent with findings from nonhuman animals and with a connectionist interpretation of these findings.
More is not necessarily better: Examining the nature of the temporal reference memory component in timing
Authors: Jones Luke A. , Wearden J. H.
Published: May 2004

Three experiments compared the timing performance of humans on a modified temporal generalization task with 1, 3, or 5 presentations of the standard duration. In all three experiments subjects received presentations of a standard duration at the beginning of a trial block and then had to judge whether each of a number of comparison stimuli was or was not the standard. The duration of the standard changed between blocks. The three experiments varied the experimental design (between or within subjects), task difficulty (how closely the comparison stimuli were spaced around the standards), and presence or absence of feedback on performance accuracy. Number of presentations of the standard never affected the proportion of identifications of the standard when it was presented, nor other features of the temporal generalization gradients observed. The implications for the operation of reference memories within the scalar timing system were explored via models that made different assumptions about how the individual presentations of the standard were stored and used.
Secondary task difficulty modulates forward blocking in human contingency learning
Authors: De Houwer Jan , Beckers Tom
Published: May 2004

The influence of a secondary task on forward blocking of human contingency ratings was examined. A smaller blocking effect was found when participants performed a highly demanding secondary task than when they performed a less demanding secondary task. The modulatory effect of secondary task difficulty was significant only when the secondary task was administered during both the learning and the test phase of the contingency judgement task. The results suggest that forward blocking in human contingency learning cannot be fully accounted for by associative processes. Instead, forward blocking seems to depend at least partially on deliberate deductive reasoning processes.
Inhibitory conditioning in honeybees
Authors: Couvillon P. A. , Bumanglag A. V. , Bitterman M. E.
Published: May 2004

Honeybees were rewarded with sucrose solution for choosing AX(a grey target, X, labelled with a distinctive stimulus, A) rather than ABX (a grey target labelled both with A and with another distinctive stimulus, B)–AX+/ABX– training. Tests of independent groups made after such training showed a clear preference not only for AX over ABX, but also for ABX over BX, and for X over BX. These experiments, along with some earlier ones to which they bring a new perspective, provide persuasive evidence, previously lacking, of inhibitory conditioning in honeybees.
Interaction between preexposure and overshadowing: Further analysis of the extended comparator hypothesis
Authors: Savastano Hernán I. , Arcediano Francisco , Stout Steven C. , Miller Ralph R.
Published: May 2004

Three experiments with rats used conditioned suppression of barpress to test predictions of the extended comparator hypothesis, which assumes that the effectiveness of (first-order) comparator stimuli in modulating responding to a target conditioned stimulus (CS) is itself modulated by other (second-order) comparator stimuli. Experiment 1 demonstrated that both pretraining exposure to the target CS alone (i.e., CS-preexposure effect, also known as latent inhibition) and pretraining exposure to a compound of the target CS and nontarget CS (i.e., compound-CS-preexposure effect) counteract overshadowing, and that posttraining deflation (i.e., extinction) of the overshadowing stimulus attenuates responding to the target CS when overshadowing is preceded by a CS-preexposure treatment (i.e., yields a CS-preexposure effect), but not when overshadowing is preceded by a compound-CS-preexposure treatment. Experiment 2 examined the consequences of posttraining associative inflation of the overshadowing stimulus or the preexposure companion stimulus following conjoint compound-CS-preexposure and overshadowing treatment. Experiment 3 examined the consequences of posttraining inflation of the overshadowing stimulus or the context following conjoint CS-alone preexposure and overshadowing treatment. The results support the expression-focused comparator view in contrast to recent acquisition-focused models of retrospective revaluation.
Unusual migration in abdomen of a wire for surgical localization of breast lesions
Authors: Grassi R. , Romano S. , Massimo M. , Maglione M. , Cusati B. , Violini M.
Published: May 2004

We report a case of migration of a surgical localization wire from the breast to the abdomen. A 41‐year‐old female underwent presurgical needle localization of a deep‐sited left‐sided breast lesion. Migration of the localization wire in the chest wall occurred during the procedure documented by imaging. Computed tomography (CT) examination showed no evidence of the wire in the left lower lung field, no peritoneal free fluid, active bleeding, or abnormalities of abdominal organ, but a metallic‐density representing the localization wire was seen for a length of 13 cm from the right diaphragmatic crus to the right psoas muscle, close to the inferior vena cava. A following CT examination showed the wire partially outside the inferior vena cava and partially inside the right iliac vein. The wire was successfully taken out by an angiographic interventional procedure.
Cerebral CT and MRI findings in cervicocephalic artery dissection
Authors: Pelkonen O. , Tikkakoski T. , Pyhtinen J. , Sotaniemi K.
Published: May 2004

Purpose: To explore the frequency and patterns of brain infarction and other brain manifestations in cervicocephalic artery dissection (CCAD) and to evaluate the correlation between vessel wall findings and infarctions.

Material and Methods: The medical records and films of 136 consecutive CCAD patients diagnosed in Oulu University Hospital during the 20‐year period since 1982 were reviewed. Five patients with no brain imaging were excluded.

Results: One‐hundred‐and‐twenty‐seven patients underwent cerebral CT and four patients MRI. Brain infarction was detected in 73 patients (56%), 43 of whom had cerebral infarction associated with anterior circulation dissection and 30 cerebellar infarction associated with posterior circulation dissection. Occlusion of the dissected vessel was accompanied by infarction in 76%, irregular stenosis in 40%, and other findings in 12%. Of the anterior circulation infarctions, territorial and subcortical infarctions and territorial infarctions with fragmentation, which are considered embolic, accounted for 95%, while only 5% were in the watershed area and considered hemodynamic. Intracranial posterior circulation dissection rarely caused infarction (in 1/11 of the dissected vessels), whereas intracranial anterior circulation dissection resulted in infarction more commonly (9/12). Altogether 23% of patients with intracranial CCAD had subarachnoid hemorrhage. Hemorrhagic transformation was present in five patients.

Conclusions: More than half of CCAD patients have cerebral or cerebellar infarction at CT or conventional MR imaging. Occlusion of the dissected vessel is accompanied by infarction more often than other vessel wall abnormalities. Most cerebral infarctions caused by arterial dissections are of embolic origin. Intracranial dissections cause subarachnoid hemorrhage in more than 20% of patients.
Comparison of intracranial 3D‐ToF‐MRA with and without parallel acquisition techniques at 1.5t and 3.0t: preliminary results
Authors: Gaa J. , Weidauer S. , Requardt M. , Kiefer B. , Lanfermann H. , Zanella F. E.
Published: May 2004

Purpose: To evaluate the performance of four 3D‐ToF magnetic resonance angiography (MRA) sequences with and without integrated parallel acquisition techniques (iPAT) at 1.5T and 3.0T in imaging intracranial vessels.

Material and Methods: Seven volunteers and 5 patients (4 aneurysms, 1 AVM) underwent 3D‐ToF‐MRA at 1.5T (Magnetom Sonata) and 3.0T (Magnetom Trio) with and without parallel acquisition techniques (iPAT) using similarly designed 8‐channel phased‐array head coils. Imaging time of the pulse sequences was set to 7.15 and 7.35 min, respectively. Images were analyzed quantitatively by calculating signal‐to‐noise (SNR) and contrast‐to‐noise (CNR) ratios of proximal M2 segments and qualitatively by using a 5‐point scale.

Results: SNR and CNR were significantly higher for both 3D‐ToF sequences at 3.0T compared with both pulse sequences at 1.5T. The highest SNR and CNR were obtained at 3.0T without iPAT. However, because of a higher spatial resolution (matrix 512×640) visualization of small vessel details was best at 3.0T with iPAT.

Conclusion: Intracranial 3D‐ToF‐MRA at 3.0T offers superior image quality compared with 1.5T, particular in the delineation of smaller vessels. In contrast to 1.5T, implementation of iPAT at 3.0T is of additional benefit since the high SNR available at 3.0T allows for higher spatial resolution without prolongation of measurement time.
Role of skeletal scintigraphy in advanced retinoblastomas
Authors: Barai S. , Bandopadhayaya G. P. , Raj P. , Julka P. K. , Kumar R. , Malhotra A. , Dhanpathi H. , Nainiwal S. , Haloi A. K.
Published: May 2004

Purpose: To document the incidence of skeletal metastases exclusively in advanced cases of retinoblastoma and to rationalize the use of preoperative skeletal scintigraphy in such patients.

Material and Methods: Preoperative bone scans of 36 consecutive patients with advanced retinoblastoma who underwent skeletal scintigraphy during 1998 to 2003 were analyzed retrospectively. Bone scans were classified as: Grade 1 (high probability scan for skeletal metastases), Grade 2 (equivocal malignant or benign abnormalities), or Grade 3 (normal or certainly benign lesions).

Results: Grade 1 scan was found in 3 (8.33%) patients; bone metastases were confirmed by additional investigations. Grade 2 scan was found in 5 (13.88%) patients; bone metastases were excluded in all by additional investigations. Grade 3 scan was found in the remaining 28 (77.77%) patients. Extraorbital extension of disease was demonstrated by fine needle aspiration of lymph nodes in five patients, which included all three patients with Grade 1 scan. In addition to lymph node metastases, two patients had intracranial extension of the disease; demonstrated by contrast‐enhanced magnetic resonance imaging of the head. One patient had liver metastases detected on abdominal ultrasound. None of the patients had skeletal metastases only.

Conclusion: Routine preoperative bone scan is not justified in patients with locally advanced retinoblastoma. Bone scan should only be performed in patients with documented extraocular metastatic disease.
An unusual cause of mediastinal widening: bilateral innominate vein aneurysms
Authors: Güney B. , Demirpolat G. , Savaş R. , Alper H.
Published: May 2004

We present a case of aneurysm of bilateral innominate veins and vena cava superior. Chest X‐ray, computed tomography, and 3D contrast enhanced magnetic resonance angiography findings are described. The etiology of venous aneurysms is reviewed and clinical management options are discussed.
Systemic‐to‐pulmonary venous shunt in superior vena cava obstruction: depiction on computed tomography venography
Authors: Kim H.‐C. , Chung J. W. , Park S. H. , Kim H. B. , Jae H. J. , Lee W. , Park J. H.
Published: May 2004

Purpose: To describe computed tomography (CT) venographic appearances of systemic‐to‐pulmonary venous shunts with CT venography and three‐dimensional reconstruction images from patients with superior vena cava obstruction.

Material and Methods: From January 1994 to April 2002, CT venography was performed in 45 patients with superior vena cava obstruction using a single‐detector helical CT scanner ( n=38) and four‐detector row CT scanner ( n=7). Analysis of CT scan data included the cause and degree of venous obstruction, the presence of pleural thickening and enhancement, and the attenuation of pulmonary veins. The causative factor for systemic‐to‐pulmonary venous shunt was evaluated using the Fisher exact test.

Results: Systemic‐to‐pulmonary venous shunts were observed in four patients (9%) who had high‐attenuated pulmonary veins and pleural enhancement on CT venography. Pleural thickening ( P=0.01) and a history of pulmonary tuberculosis ( P=0.034) are statistically significant risk factors.

Conclusion: CT venography showed strong pleural enhancement and high‐attenuated pulmonary veins indicating systemic‐to‐pulmonary venous shunts. Radiologists should study the earlier enhancement of pulmonary veins in patients with superior vena cava obstruction.
Factors related to acute hydrocephalus after subarachnoid hemorrhage
Authors: Jartti P. , Karttunen A. , Jartti A. , Ukkola V. , Sajanti J. , Pyhtinen J.
Published: May 2004

Purpose: To evaluate the influence of the amount and distribution of blood on acute ventricular enlargement in subarachnoid hemorrhage (SAH).

Material and Methods: In a retrospective study, non‐contrast computed tomography (CT) images of 180 patients with aneurysmal SAH were analysed by two neuroradiologists. The amount and distribution of the hemorrhage were scored, and prospective hydrocephalus was identified on the basis of acute CT images by calculating the cella media index, by measuring the width of the third ventricle, and by visual impression. Statistical analysis was done using the logistic regression model, analysis of variance, and chi‐square test.

Results: The incidence of acute hydrocephalus was higher among the patients with blood distributed in the anterior, lateral, and basal regions (70.8%) than among the patients who did not have blood distributed in all three areas ( P=0.010). The proportion of acute hydrocephalus differed depending on the type of hemorrhage ( P<0.001). Intraventricular hemorrhage was the most consistent predictive factor in the logistic regression model, while the other predictive factors included the total blood amount score and the volume of intracerebral hemorrhage.

Conclusions: A positive correlation was found between acute hydrocephalus and the amount of subarachnoid and, more importantly, intraventricular blood. This is consistent with the literature and confirms the current pathophysiologic concepts that the acute hydrocephalus following SAH is an obstructive form of hydrocephalus.
Long‐term results after endovascular repair of abdominal aortic aneurysms with the stentor and vanguard stent‐graft
Authors: Engellau L. , Albrechtsson U. , Norgren L. , Larsson E.‐M.
Published: May 2004

Purpose: To present a single institution experience of long‐term results after endovascular repair of abdominal aortic aneurysms (AAA) with the Stentor and Vanguard stent‐grafts.

Material and Methods: Twenty‐three patients (20 men, 3 women; mean age 68 years, range 53–81 years) were included in this prospective study. A first generation nitinol stent‐graft (Stentor™) was used in 12 patients and a second generation (Vanguard™) in 11 patients. Follow‐up was performed with magnetic resonance imaging (MRI) with contrast‐enhanced MR angiography (CE MRA) at 1, 6, and 12 months, and thereafter annually (median follow‐up 3 years; range 8 months to 8 years). A conventional radiograph of the abdomen was also performed. Before secondary intervention the findings on MRI with CE MRA were confirmed with spiral computed tomography (CT) and/or angiography (DSA).

Results: Only one patient (4%) had no complication. Endoleak was found in 15 patients (65%), graft migration in 8 (35%), and graft deformation in 18 (78%). Secondary endovascular repair was required in 7 patients (30%) and 7 (30%) were converted to open repair.

Conclusion: Complications with the Stentor and Vanguard stent‐grafts were common. Long‐term follow‐up of endovascularly repaired AAA is mandatory.
Role of radiology in occupational medicine
Authors: Vehmas T.
Published: May 2004

This review discusses the contribution of radiology to occupational medicine as well as work‐related problems in radiology departments. Research issues are emphasized. Radiology has been used especially when diagnosing occupational respiratory and locomotive system problems and solvent‐induced encephalo‐ and hepatopathy. The aim of research in these areas is usually to characterize occupational diseases and to identify physico‐chemical hazards in the work place by comparing between groups of workers and non‐exposed controls. Radiological imaging allows an objective characterization of the disease, and it may clarify the pathogenesis of the process and provide a useful epidemiological tool. Advanced statistical methods are often needed to adjust analyses for confounding variables. As the diagnostic requirements are increasing, more sensitive and sophisticated radiological methods, such as high‐resolution computed tomography, magnetic resonance imaging and magnetic resonance spectroscopy, may be required for the early recognition of occupational health risks. This necessitates good cooperation between occupational health units and well‐equipped imaging departments. Considering occupational problems in radiology departments, the increasing use of digital radiology requires ergonomic measures to control and prevent locomotive problems caused by work with computers. Radiation protection measures are still worth concern, especially in interventional radiology.
Therapeutic impact of abdominopelvic computed tomography in patients with acute abdominal symptoms
Authors: Chambers A. , Halligan S. , Goh V. , Dhillon S. , Hassan A.
Published: May 2004

Purpose: To determine the diagnostic and therapeutic impact of abdominopelvic computed tomography (CT) in patients with acute abdominopelvic pain.

Material and Methods: Referring clinicians completed pre‐CT and post‐CT questionnaires for 50 patients in whom CT had been requested because of acute abdominopelvic pain. Clinicians recorded their leading diagnosis, confidence in this, and intended management. Following CT, clinicians again recorded these responses in the light of CT findings. Responses pre‐CT and post‐CT were compared in order to determine diagnostic and therapeutic impact.

Results: Diagnostic confidence rose significantly following CT (mean score 6.8 pre‐CT versus 8.3 post‐CT; P<0.0001). Intended management changed because of CT findings in 29 (58%) patients: 14 (28%) subjects whose intended management was surgical were treated medically and an additional 2 were transferred to gynecological care; 4 patients whose intended management was medical were treated surgically; 2 patients whose intended management was medical were treated by percutaneous drainage; a patient whose intended management was percutaneous drainage was treated by surgery. Of 6 patients with uncertain management pre‐CT, 2 were treated surgically and 4 medically. The leading diagnosis also changed as a consequence of CT in 7 (33%) of 21 patients in whom intended management did not alter.

Conclusion: CT in patients with acute abdominopelvic pain has considerable diagnostic and therapeutic impact, altering management in 58% of patients studied. The major effect is to avert intended laparotomy.
Bone stress injuries
Authors: Kiuru M. J. , Pihlajamäki H. K. , Ahovuo J. A.
Published: May 2004

Bone stress injuries are due to cyclical overuse of the bone. They are relatively common in athletes and military recruits but also among otherwise healthy people who have recently started new or intensive physical activity. Diagnosis of bone stress injuries is based on the patient's history of increased physical activity and on imaging findings. The general symptom of a bone stress injury is stress‐related pain. Bone stress injuries are difficult to diagnose based only on a clinical examination because the clinical symptoms may vary depending on the phase of the pathophysiological spectrum in the bone stress injury. Imaging studies are needed to ensure an early and exact diagnosis, because if the diagnosis is not delayed most bone stress injuries heal well without complications.
Book review
Authors: Wegenius G.
Published: May 2004

Atlas of Nontumor Pathology. First series Fascicle 2. Non- Neoplastic Disorders of the Lower Respiratory Tract. Edited by Donald West King. The American Registry of Pathology. Armed Forces Institute of Pathology, Washington, DC, USA. ISBN 1-881-0141-79-4.
A retained neurointerventional microcatheter fragment in the anterior communicating artery aneurysm in multi‐slice computed tomography angiography
Authors: Teksam M. , McKinney A. , Truwit C. L.
Published: May 2004

We present a case of multi‐slice computed tomography angiography of a 60‐year‐old patient with a retained fragment of microcatheter within an anterior communicating artery (AcomA) aneurysm. This is a rare complication of Guglielmi detachable coil embolization. After an unsuccessful embolization procedure, the patient underwent surgery. During clipping of an AcomA aneurysm, the microcatheter traveled up the pericallosal branch of the right anterior cerebral artery. Subsequently, the microcatheter fragment did not prevent normal blood flow through the artery, and the patient has been doing well without neurological sequelae.
Dose reduction in computed tomography by individualized scan protocols
Authors: Jangland L. , Sanner E. , Persliden J.
Published: May 2004

Purpose: To find a method of adjusting the mAs‐value in relation to the size of the patient undergoing computed tomography (CT) examination as a means of minimizing the radiation dose to the patient.

Material and Methods: A correction factor to be applied on the tube charge for each patient was calculated using two mathematical methods. This approach was tested on 4 Perspex phantoms of different sizes and geometries. Noise was measured in the images with and without use of the correction factors. Retrospectively, correction factors were calculated for 12 CT examinations of the abdomen and the dose reduction was estimated for these patient studies.

Results: The variations in noise measured in the images of the different phantoms were dramatically reduced by both methods. The retrospectively performed patient study showed that the largest correction factor was 7 times greater than the smallest, which means that a dose reduction factor of 7 is possible in the extreme case.

Conclusion: Our proposed methods of adjusting the applied tube charge (mAs‐value) in relation to the size of the patient can be used on the vast majority of CT systems. The potential for dose reduction is great, especially for small patients.
Computed tomography‐guided pulmonary nodule localization before thoracoscopic resection
Authors: Hänninen E. L. , Langrehr J. , Raakow R. , Röttgen R. , Schmidt S. , Pech M. , Ricke J. , Felix R.
Published: May 2004

Purpose: To assess the success rate and complication rate of a CT‐guided pulmonary nodule‐marker system before thoracoscopic resection.

Material and Methods: In 24 patients (15 M, 9 F; age range, 18–71 years) a total of 25 pulmonary nodules (in 1 patient 2 lesions simultaneously) were marked with a special wire under CT‐guidance and then thoracoscopically resected. We evaluated lesion size, lesion distance to the pleura, the time of intervention, complications, and thoracoscopic success rate.

Results: Mean lesion size was 7 mm (range 4–15 mm) and mean lesional distance to the pleura was 13 mm (range 2–31 mm). The pulmonary nodule‐marker system was positioned successfully in all 25 pulmonary nodules within 5–11 min (mean 7.5 min). Minimal pneumothoraces were observed in five patients with no requirements of chest drains. In addition, no bleeding complications or hematothorax were observed. All 25 pulmonary nodules could be resected thoracoscopically. However, in one patient (4%), the guide‐wire dislocated during thoracoscopy, but the lesion could be successfully resected during thoracoscopy.

Conclusion: The CT‐guided placement of the pulmonary nodule‐marker system used here offers a safe and accurate guide for the localization of small pulmonary nodules during thoracoscopic resection.
Primary intracranial myxopapillary ependymomas: report of two cases and review of the literature
Authors: Tseng Y.‐C. , Hsu H.‐L. , Jung S.‐M. , Chen C.‐J.
Published: May 2004

Myxopapillary ependymoma is a variant of ependymoma occurring almost exclusively in the conus medullaris or filum terminale. Myxopapillary ependymoma found primarily in the brain is extremely rare. Two such cases appearing at the 4th ventricle and cerebral falx are reported. The imaging features of such tumors are a primary cystic mass with strong enhancement at its solid part. Myxopapillary ependymoma should be a possible differential diagnosis when an intracranial cystic tumor is found.
Imaging findings of urachal mucinous cystadenocarcinoma associated with pseudomyxoma peritonei
Authors: Takeuchi M. , Matsuzaki K. , Yoshida S. , Nishitani H. , Uehara H.
Published: May 2004

Pseudomyxoma peritonei is an uncommon neoplastic condition in which gelatinous fluid‐like materials are observed in the peritoneal cavity caused by the dissemination of mucinous adenocarcinoma. Although ruptured appendiceal mucocele is the most common cause, tumors arising from other organs may also cause pseudomyxoma peritonei. We report the imaging findings of an extremely rare case of urachal mucinous adenocarcinoma associated with pseudomyxoma peritonei on computed tomography and magnetic resonance imaging with histopathologic correlation.
Usefulness of reversed display of soft‐copy abdominal radiographs for urinary calculi detection
Authors: Kang S.‐S. , Kim J. K. , Ryu J.‐A. , Choi N. , Bae S.‐J. , Kim B.
Published: May 2004

Purpose: To determine the usefulness of reversed display of soft‐copy abdominal radiographs for urinary calculi detection.

Material and Methods: Sixty radiographs with a single urinary calculus less than 5 mm in the long diameter (15 in the kidney; 15 in the proximal ureter; 15 in the mid‐ureter, 15 in the distal ureter) and 15 radiographs without calculi were evaluated. Four readers blinded to the presence or absence of urinary calculi on each radiograph reviewed the radiographs in the conventional display, reversed display, and combination of conventional and reversed displays at 1‐week intervals. All images were evaluated in random order and the presence or absence of urinary calculi was interpreted using the confidence score from 1 to 5.

Results: Multireader analysis for calculi in all locations showed a greater area under the receiver operating curve for combination of the two displays (0.764) than for the conventional display alone (0.655) ( P=0.031). In the single‐reader analysis for calculi in all locations, the third reader showed a greater area under the receiver operating curve for the reversed display (0.784) than for the conventional display (0.622) ( P=0.027). Multireader analysis of the calculi in the kidney showed a greater area under the receiver operating curve for combination of the two displays (0.824) than for the conventional display alone (0.703) ( P=0.043).

Conclusion: The reversed display of soft‐copy abdominal radiographs may be useful for urinary calculi detection.
Multicenter evaluation of a new laser guidance system for computed tomography intervention
Authors: Brabrand K. , AaløKKen T. M. , Krombach G. A. , Günther R. W. , Tariq R. , Magnusson A. , Lindgren P.‐G.
Published: May 2004

Purpose: To measure the accuracy of laser‐guided punctures and to evaluate the usefulness of the developed laser‐guided system.

Material and Methods: The study included 67 patients referred for computed‐tomography‐guided puncture. The majority of the punctured lesions were located in the chest (28 patients) or abdomen (19 patients). The mean diameter of the lesion was 3.1 cm, and the mean path length was 6.8 cm. The laser guide was movable along a horizontal or vertical rail and not physically connected to the CT unit. The angle of insertion was entered manually into the display of the unit by the interventional radiologist. A prospective multicenter trial was carried out.

Results: A mean of 1.1 needle passes were necessary to reach the target, and in 55 (84.6%) of the patients the target was reached on the first needle pass. The mean deviation of the needle from the preselected angle was 1.8°. The mean targeting time (from the initial localizing scan until the needle was in the target) was 15.6 min. In every case, both the usefulness and the ease of use of the laser guidance system were subjectively evaluated on a 5‐point scale; the mean usefulness score was 4.5, while the mean ease of use score was 4.7.

Conclusion: Different users at four different centers found the laser guidance system useful and easy to use. A high level of accuracy of the puncture angle was obtained in most cases.
Pleuropulmonary blastoma in the area of a previously diagnosed congenital lung cyst: report of two cases
Authors: Hasiotou M. , Polyviou P. , Strantzia C. M. , Pourtsidis A. , Stinios I.
Published: May 2004

Pleuropulmonary blastoma (PPB) is a rare primary malignant pulmonary tumor in pediatric patients. We report the development of PPB in the area of a previous pulmonary cyst in two children, one boy and one girl 5 and 12 years old, respectively. We present the clinical and radiological findings. A short review of the literature is included.
Book review
Authors: Malcus P.
Published: May 2004

Ultrasound and Endoscopic Surgery in Obstetrics and Gynaecology. A Combined Approach to Diagnosis and Treatment. Edited by D. Timmerman, J. Deprest, and T. Bourne. Berlin, Heidelberg: Springer-Verlag, 2003. ISBN 3 540 76212 4. 344 pages, 150 illustrations. Price hardcover: %euro;179.00.
A System Approach to Deterring and Influencing Terrorists
Authors: Davis Paul K. , Jenkins Brian Michael
Published: May 2004

Counterterrorism efforts in the United States focus largely on a combination of offensive actions against terrorists abroad and defense of the U.S. homeland and U.S. and allied interests worldwide. This paper provides a framework for conceiving another necessary component of the struggle, the influence component. Classic deterrence is but one influence among many. This paper recommends approaching the issue as a “system problem” in which the many different components of terrorist organizations are considered and appropriate influences applied accordingly. The influences discussed range from various forms of coercion to the competition of ideas.
An Economic Model of Terrorism
Authors: Brock Blomberg S. , Hess Gregory D. , Weerapana Akila
Published: May 2004

We develop an economic model of terrorism. Groups undertake violent activities to change the status quo when they are unable to bring about drastic political change in the face of limited access to economic opportunity. Furthermore, these groups are more likely to resort to terrorist activity when they face powerful policy-making elites who can't be uprooted easily, by legitimate means or otherwise. If, on the other hand, the elite groups currently in power are weak but can't be removed from power legitimately, the dissident groups are likely to initiate rebellion activity, such as civil wars and coups, to take over the rule of the governing elite themselves. In particular, the model exhibits multiple equilibria. For example, one equilibrium can be sustained where groups with limited access to opportunity may find it rational to engage in terrorist activities while policy-maker elites may find it rational not to engage in opening access to these groups. The result is, then, a pattern of reduced economic activity and increased terrorism. An alternative equilibrium can be sustained where access is more abundant and terrorism is reduced.
Constitution or Conflict?
Authors: Grossman Herschel I.
Published: May 2004

Constitutional resolution of disputes between constituent groups of a polity avoids the incremental costs of civil conflict. But, the political process prescribed by a constitution provides a viable alternative to civil conflict only if the constitution is self-enforcing. Theoretical analysis reveals that the following properties help to make it possible to design a self-enforcing constitution that can settle recurring disputes:

• No party to the disputes has a big advantage in civil conflict.

• The parties to the disputes expect the incremental costs of civil conflict to be large relative to the importance of the disputes that arise between them.

• The parties are greatly concerned about the future consequences of their current actions.

Theoretical analysis also reveals that a self-enforcing constitution can require limitations on the prerogatives of winners of constitutional contests such that on average outcomes under the constitution are not too favorable to any one party and such that the outcome of each constitutional contest does not matter too much. The paper concludes with historical examples that illustrate the broad applicability of the theoretical analysis.
On the Stability of Group Formation: Managing the Conflict Within
Authors: Garfinkel Michelle R.
Published: May 2004

This paper develops a positive analysis of stable group formation, highlighting the role of conflict management within groups. The analysis builds on a simple economic model that features a “winner-take-all” contest for control of some resource. When a group forms, members pool their efforts in that contest and, if successful, apply the resource to a joint production process. While reducing the severity of conflict over the contestable resource relative to the case of individual conflict, the formation of groups adds another layer of conflict, that is, one between the members of the winning group over the distribution of their joint product. The effectiveness of conflict management in enabling groups to resolve this second layer of conflict in more “peaceful” ways has some important implications for the equilibrium structure of groups as well as for the allocation of resources.
Innovation and the Technology of Conflict During the Napoleonic Revolution in Military Affairs
Authors: Franck Raymond E.
Published: May 2004

This essay is intended as a modest response to Prof. Hirshleifer's call for research in the “macrotechnology” of conflict. It specifically considers innovations undertaken by the Prussian and British Armies in response to the problems posed by the Napoleonic Revolution in Military Affairs (RMA) and the resulting ascendancy of the French Army. For various reasons, the Prussians chose an “emulating” response to the French; the British chose “offsetting.” The discussion following considers the Napoleonic innovations and the two responses, both of which proved effective. As a result, there is support for the view that military innovation is, to a significant extent, a military choice made from a menu of military measures within the context of military-political competition.
A VCO with Harmonic Suppressed and Output Power Improved Using Defected Ground Structure
Authors: Liu Haiwen , Sun Xiaowei , Li Zhengfan
Published: May 2004

In this paper, a novel defected ground structure (DGS) is proposed for suppressing harmonic and increasing the output power of a voltage‐controlled oscillator (VCO) in microwave circuits. The DGS is formed with connecting in parallel two periodic structures which have different center frequencies (in a ratio of 2:3) of the stopband and provides the bandgap characteristic in certain frequency bands. Simulated and experimental results show that the
microstrip line with DGS has a wide low‐pass band for the fundamental frequency and a stopband for the second harmonic with good performance. To evaluate the effects of DGS on microwave VCOs, two GaAs field‐effect transistor (FET) VCOs have been designed and fabricated. One of them has a 50Ω
microstrip line with DGS at the output section, while the other has only a 50Ω
straight line. Measured results show that DGS suppresses the second harmonic more than −20
dBm at the output and yields improved output power by 3 − 5%.
Modification of n‐Si Characteristics by Annealing and Cooling at Different Rates
Authors: Salih Subhi K. , Hilal Hikmat S. , Sa′deddin Iyad A. , Sellier Elisabeth , Campet Guy
Published: May 2004

The effect of annealing of the n‐Si semiconductor on its characteristics in photoelectrochemical systems has been investigated. The annealing improved the dark current density vs. potential plots. The surface was improved by annealing, as manifested by SEM results. The effect of the cooling rate on preheated n‐Si wafers was also investigated. It was found that the slowly cooled electrodes gave better dark current density vs. potential plots,
for samples annealed at lower than 550°C. For samples annealed at higher temperatures, quenching gave better dark‐current density vs. potential plots. SEM measurements showed parallel results to these findings. Enhanced surface textures were observed for slowly cooled wafers from temperatures below 550°C. Samples quenched from temperatures above 550°C showed better surfaces than slowly cooled counterparts.
Active‐Only Current Controlled Summing/Difference Amplifiers Using CCCIIs
Authors: Maheshwari Sudhanshu
Published: May 2004

Novel active‐only summing/difference amplifiers employing only current controlled conveyors (CCCIIs) are presented. The circuits possess high input impedance, current controllable gain, good linearity and dynamic range, low THD and are suited for IC implementation. SPICE simulation results are included to verify the circuits.
Structural, Optical and Electrochromic Properties of Sol–Gel V2O5Thin Films
Authors: Benmouss M. , Outzourhit A. , Jourdani R. , Bennouna A. , Ameziane E. L.
Published: May 2004

Vanadium pentoxide thin films are prepared by the sol–gel route by dissolving V2O5
powder (99.5% purity) in H2O2
solution. The solution is spin‐coated on glass substrates for optical (UV–VIS–NIR) and XRD analysis, and on ITOcoated glass substrates for electrochromic measurements. The samples are then annealed at 150°C for 1 hour. The resulting films have a yellow‐orange color, typical of polycrystalline V2O5. XRD measurements have shown that after annealing in air at 400°C the structure of the films has a c‐axis preferred orientation, the (0 0 1)‐type planes lying
parallel to the substrate. SEM analysis revealed a smooth surface. The films’ optical and physical constants (n, α,
Eg, the thickness d and the mean thickness inhomogeneity s) are calculated using a simple and accurate method based on the transmission spectrum alone. The films’ electrochromism is studied using cyclic voltammetry (CV) and chronoamperometry in propylene carbonate solution containing 1 mol/l LiCIO4. The films show reversible multichromism (yellow–green–blue) upon Li+
ion insertion/extraction. The absorbance of films colored at three different potentials is measured in the UV–VIS–PIR wavelength range, and this study shows that the changes in
the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works.
Modeling of the I–V Characteristics for LDD‐nMOSFETs in Relation with Defects Induced by Hot‐Carrier Injection
Authors: Marrakh R. , Bouhdada A.
Published: May 2004

The hot‐carrier injection is observed increasingly to degrade the I–V characteristics with the scaling of MOS transistors. For the lightly doped drain MOS transistor the injection of the hot‐carriers, caused by the high electric field in the MOS structure, is localized in the LDD region. The modeling of the drain current in relation to defects due to the hot‐carrier injection allows us to investigate the I–V characteristics and the transconductance of devices. Consequently, we can know the amount of the device degradation caused by these defects in order to
find technological solutions to optimize reliability.
Interleukin (IL)‐1 gene polymorphisms: relevance of disease severity associated alleles with IL‐1β and IL‐1ra production in multiple sclerosis
Authors: Schrijver Hans M. , van As Jaco , Crusius J. Bart A. , Dijkstra Christien D. , Uitdehaag Bernard M. J.
Published: May 2004

Background: Multiple sclerosis (MS) is an autoimmune disorder, with a considerable genetic influence on susceptibility and disease course. Cytokines play an important role in MS pathophysiology, and genes encoding various cytokines are logical candidates to assess possible associations with MS susceptibility and disease course. We previously reported an association of a combination of polymorphisms in the interleukin (IL)‐1B and IL‐1 receptor antagonist (IL − 1RN) genes (i.e. IL − 1RN allele 2 + /IL − 1B+3959allele 2−) with disease severity in MS. Extending this observation, we investigated whether IL‐1β and IL‐1ra production differed depending on carriership of this gene combination.

Methods: Twenty MS patients and 20 controls were selected based upon carriership of the specific combination. In whole blood, in vitro IL‐1β and IL‐1ra production was determined by enzyme‐linked immunosorbent‐assay after 6 and 24 h of stimulation with lipopolysaccharide.

Results: Carriers of the specific combination produced more IL‐1ra, especially in MS patients, although not significantly. IL‐1ra production was significantly higher in individuals homozygous for IL − 1RN allele 2. In patients, Il‐1ra production was higher and IL‐1β production lower compared with controls. In primary progressive patients, the IL‐1β /IL‐1ra ratio was significantly lower than in relapsing‐remitting patients.

Conclusion: Our results suggest higher in vitro IL‐1ra production in carriers of IL − 1RN allele 2, with an indication of an allelic dose‐effect relationship.
Dexamethasone prevents granulocyte‐macrophage colony‐stimulating factor‐induced nuclear factor‐κB activation, inducible nitric oxide synthase expression and nitric oxide production in a skin dendritic cell line
Authors: Vital Ana Luísa , Gonçalo Margarida , Cruz M. Teresa , Figueiredo Américo , Duarte Carlos B. , Lopes M. Celeste
Published: May 2004

Aims: Nitric oxide (NO) has been increasingly implicated in inflammatory skin diseases, namely in allergic contact dermatitis. In this work, we investigated the effect of dexamethasone on NO production induced by the epidermal cytokine granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) in a mouse fetal skin dendritic cell line.

Methods: NO production was assessed by the method of Griess. Expression of the inducible isoform of nitric oxide synthase (iNOS) protein was evaluated by western blot analysis and immunofluorescence microscopy. Western blot analysis was also performed to evaluate cytosolic IkappaB‐alpha (IκB‐α) protein levels. The electrophoretic mobility shift assay was used to evaluate the activation or inhibition of nuclear factor kappa B (NF‐κB).

Results: GM‐CSF induced iNOS expression and NO production, and activated the transcription factor NF‐κB. Dexamethasone inhibited, in a dose‐dependent manner, NO production induced by GM‐CSF. Addition of dexamethasone to the culture, 30 min before GM‐CSF stimulation, significantly inhibited the cellular expression of iNOS. Dexamethasone also inhibited GM‐CSF‐induced NF‐κB activation by preventing a significant decrease on the IκB‐α protein levels, thus blocking NF‐κB migration to the nucleus.

Conclusions: The corticosteroid dexamethasone inhibits GM‐CSF‐induced NF‐κB activation, iNOS protein expression and NO production. These results suggest that dexamethasone is a potent inhibitor of intracellular events that are involved on NO synthesis, in skin dendritic cells.
Signal transduction pathways in mast cell granule‐mediated endothelial cell activation
Authors: Chi Luqi , Stehno-bittel Lisa , Smirnova Irina , Stechschulte Daniel J , Dileepan Kottarappat N.
Published: May 2004

Background: We have previously shown that incubation of human endothelial cells with mast cell granules results in potentiation of lipopolysaccharide‐induced production of interleukin‐6 and interleukin‐8.

Aims: The objective of the present study was to identify candidate molecules and signal transduction pathways involved in the synergy between mast cell granules and lipopolysaccharide on endothelial cell activation.

Methods: Human umbilical vein endothelial cells were incubated with rat mast cell granules in the presence and absence of lipopolysaccharide, and IL‐6 production was quantified. The status of c‐Jun amino‐terminal kinase and extracellular signal‐regulated kinase 1/2 activation, nuclear factor‐κB translocation and intracellular calcium levels were determined to identify the mechanism of synergy between mast cell granules and lipopolysaccaride.

Results: Mast cell granules induced low levels of interleukin‐6 production by endothelial cells, and this effect was markedly enhanced by lipopolysaccharide. The results revealed that both serine proteases and histamine present in mast cell granules were involved in this activation process. Mast cell granules increased intracellular calcium, and activated c‐Jun amino‐terminal kinase and extracellular signal‐regulated kinase 1/2. The combination of lipopolysaccharide and mast cell granules prolonged c‐Jun amino‐terminal kinase activity beyond the duration of induction by either stimulant alone and was entirely due to active proteases. However, both proteases and histamine contributed to calcium mobilization and extracellular signal‐regulated kinase 1/2 activation. The nuclear translocation of nuclear factor‐κB proteins was of greater magnitude in endothelial cells treated with the combination of mast cell granules and lipopolysaccharide.

Conclusions: Mast cell granule serine proteases and histamine can amplify lipopolysaccharide‐induced endothelial cell activation, which involves calcium mobilization, mitogen‐activated protein kinase activation and nuclear factor‐κB translocation.
Allergic diseases, drug adverse reactions and total immunoglobulin E levels in lupus erythematosus patients
Authors: Wozniacka Anna , Sysa-Jedrzejowska Anna , Robak Ewa , Samochocki Zbigniew , Zak-Prelich Malgorzata
Published: May 2004

Background: The association of allergic diseases, drug adverse reactions and elevated total immunoglobulin E (IgE) concentration in systemic lupus erythematosus patients remains controversial. The aim of the study was to investigate the prevalence of those features in active and inactive systemic lupus erythematosus patients, and in the control group as well.

Methods: Total IgE concentration was evaluated by enzyme‐linked immunosorbent assay

Results and conclusions: The results of our study revealed that concomitant allergic diseases were not more frequent in systemic lupus erythematosus patients than in the general population. Total IgE concentration was significantly higher during the active stage of the disease. Drug reactions were very frequent but not connected with IgE elevation. Our results indicate that IgE may play a role in lupus pathogenesis, especially in the active phase of the disease.