bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of layer composition and thickness in AlGaN/GaN HEMT structures by spectroscopic ellipsometry
Authors: Baeumler M. , Müller S. , Köhler K. , Wagner J. 
Published: February 2005

AbstractAlGaN/GaN heterostructures for power applications, grown on sapphire substrates by metal organic vapor phase epitaxy (MOVPE) in a multiwafer reactor were analyzed by spectroscopic ellipsometry (SE). The thickness of the individual layers as well as the AlGaN bandgap energy were extracted from pseudodielectric function spectra 〈ε〉 for photon energies ranging from 2 to 5 eV. The experimental 〈ε〉 spectra were analyzed using a multilayer approach, describing the dielectric functions of the individual layers by a parametric oscillator model. The potential of the technique will be demonstrated using on‐wafer homogeneity as well as wafer‐to‐wafer variation within the same growth run in the MOVPE reactor as examples. SE was found to be capable of detecting relative variations in the Al content of 1% and the AlGaN layer thickness of 10%. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High magnetic field studies of 1/f noise in GaN/AlGaN heterostructure field effect transistors
Authors: Dyakonova N. , Rumyantsev S. L. , Shur M. S. , Meziani Y. , Pascal F. , Hoffmann A. , Fareed Q. , Hu X. , Bilenko Yu. , Gaska R. , Knap W. 
Published: February 2005

AbstractThe influence of strong magnetic field on the 1/f noise in AlGaN/GaN metal‐oxide‐Semiconductor heterostructure field effect transistors (MOSHFETs) has been studied. The independence of 1/f noise on the magnetic fields up to 10 T where the strong geometric magneto‐resistance has been observed, shows that the carrier number fluctuations is the dominant mechanism of the noise in these devices. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An approach to literate and structured formal developments
Authors: Simons Martin , Weber Matthias 
Published: February 2005

Abstract
We present an approach to the literate and structured presentation of formal developments. We discuss the presentation of formal developments in a logical framework and distinguish three aspects: language-related aspects, structural aspects of proofs, and presentational aspects. We illustrate the approach by two examples: a simple mathematical proof of the Knaster-Tarski fixpoint theorem, and a formalization of the VDM development of a revision management system.
Sexual and vegetative reproduction in the aboveground part of a dioecious clonal plant, Dioscorea japonica (Dioscoreaceae)
Authors: Mizuki Inoue , Ishida Kiyoshi , Kikuzawa Kihachiro 
Published: February 2005

AbstractIn dioecious clonal plants, the reproductive effort required to set seeds will be responsible for the larger investment in sexual reproduction by females. If there will be a trade‐off in resource allocation between sexual and clonal reproduction, this differential sexual reproduction will lead to sexual differentiation in the relative amount of clonal reproduction. To test this prediction, we studied differences between the sexes in their phenologies and investments in sexual and vegetative reproduction (clonal reproduction by means of bulbils) with respect to ramet size in a dioecious clonal plant, Dioscorea japonica Thunb. The period of bulbil production overlapped the period during which infructescences developed. Females flowered later, produced heavier inflorescences, and fewer flowers per inflorescence than did males. Regression analysis using the size of the individual plants demonstrated that large females made smaller investments in inflorescences and larger investments in sexual reproduction than did large males. In contrast, females invested fewer resources in vegetative reproduction than did males. However, the total investments in sexual and vegetative reproduction did not differ between the sexes. These results supported our hypothesis on the sexual differentiation in sexual and clonal reproduction.
The Prevalence of Encopresis in a Multicultural Population
Authors: van der Wal M F , Benninga M A , Hirasing R A 
Published: February 2005

ABSTRACTBackground:Population‐based studies on the prevalence of encopresis in children are scarce and generally outdated. Prevalence estimates based on clinical studies are unreliable because parents tend to be reticent to seek medical help for this problem. Professional help is necessary, however, because encopresis can lead to serious psychosocial health problems. The authors examined the prevalence of encopresis in children, the frequency of visits made to general practitioners for encopresis and the psychosocial health problems of encopretic children.Methods:This population‐based study involved 13,111 parents and their 5‐ to 6‐year‐old children and 9,780 parents and their 11‐ to 12‐year‐old children, all residents of Amsterdam, the Netherlands.Results:The prevalence of encopresis was 4.1% in the 5‐to‐6 age group and 1.6% in the 11‐to‐12 age group. Encopresis was more frequent among boys and children from the very depressed areas of the city. Encopresis was less frequent among Moroccan and Turkish children. A defecation frequency of less than three per week was found in 3.8% of the 5‐ to 6‐year‐olds and 10.1% of the 11‐ to 12‐year‐olds with encopresis. Only 37.7% of the 5‐ to 6‐year‐olds and 27.4% of the 11‐ to 12‐year‐olds who had encopresis had ever been taken to see a doctor for this problem. Psychosocial problems were far more common among children with encopresis than among normal children.Conclusions:Encopresis is a common condition that is often associated with psychosocial health disorders but only a small proportion of the children with encopresis are taken to a general practitioner to discuss their problem.
Shigella Antibiotic Resistance in Central Turkey: Comparison of the Years 1987‐1994 and 1995‐2002
Authors: Özmert Elif N , Göktürk Bahar , Yurdakök Kadriye , Yalçin S Songül , Gür Deniz 
Published: February 2005

ABSTRACTBackground:The epidemiology and antibiotic susceptibility of Shigella species changes over time. Updated susceptibility knowledge is necessary for appropriate empirical antibiotic treatment.Methods:In this study the clinical characteristics and the antibiotic susceptibility test results of Shigella species isolated from patients admitted to Hacettepe University Ihsan Doğramac Children's Hospital Diarrheal Diseases Training and Treatment Unit between 1995‐2002 (n = 218) were evaluated. The results were compared with the results of 1987‐1994 from the same center (n = 618).Results:The predominant species was S. sonnei in both periods with increasing prevalence in the later period (64% and 71.5% respectively, P < 0.05). Although the prevalence of bloody diarrhea among Shigella cases did not change between periods, the prevalence of mild to moderate dehydration (11% and 20.6%) increased. Approximately 40% of cases were prescribed antibiotics on the suspicion of shigellosis. When the two periods were compared, Shigella resistance to trimethoprim/sulfamethoxazole increased from 39% to 70% (P < 0.0001), whereas resistance to ampicillin decreased from 41% to 23% (P < 0.0001). However, the resistance of S. flexneri to ampicillin was found to be quite high (72.9%) between 1995‐2002. No Shigella species resistant to ciprofloxacin was detected. Multi‐drug resistance was present in 52 (24%) of the cases, of which 10 were S. sonnei (6.3%) and 42 S. flexneri (26.4%) (P < 0.0001).Conclusion:The need to treat all Shigella cases in areas where S. sonnei is predominant should be reevaluated, as should the appropriate empirical antibiotic.
Altered Bone Mass in Children at Diagnosis of Crohn Disease: A Pilot Study
Authors: Harpavat Manisha , Greenspan Susan L , O'Brien Carey , Joyce Chang Chung‐Chou , Bowen A'Delbert , Keljo David J 
Published: February 2005

ABSTRACTObjectives:Recent studies have indicated that bone mineral density is reduced in children with inflammatory bowel disease. The exact cause of this reduction is unclear, but it is often attributed to corticosteroid use. This study examined the prevalence of reduced bone mass in otherwise healthy children newly diagnosed with Crohn disease without previous corticosteroid exposure.Methods:Eighteen steroid‐naïve children newly diagnosed with Crohn disease underwent dual energy x‐ray absorptiometry. Disease activity, growth and pubertal development, nutritional assessment and bone mass measurements were recorded. z scores were adjusted for bone age.Results:Five of the 18 patients (28%) had a total bone mineral density z score less than −1 (one had a z score less than −2). Ten (56%) subjects had lumbar spine bone mineral density z scores less than −1 (two had z score less than −2). The subjects had significantly reduced mean lumbar spine bone mineral density z scores (P = 0.002). Delayed pubertal development correlated with whole body bone mineral density z scores (r = 0.64; P = 0.004). Most subjects were not meeting United States recommended dietary allowances for daily intake of calcium, vitamin D and total calories. The majority of subjects were not participating in weight‐bearing physical activity.Conclusion:Decreased bone mass is common in steroid naïve children newly diagnosed with Crohn disease. Crohn disease appears to contribute to impaired bone mass independent of corticosteroid therapy.
Can We Alter The Natural History Of Crohn Disease In Children?
Authors: Hyams Jeffrey S , Markowitz James F 
Published: February 2005

ABSTRACTThe natural history of Crohn disease is characterized by recurrent bouts of active disease, the consequences of which can severely impair sufferers' physical and social functioning. Not only does the illness cause day‐to‐day morbidity for children but the consequence of the chronic inflammatory process also commonly results in the need for major intestinal surgery. The present challenge facing physicians treating children with Crohn disease is to alleviate symptoms and prolong periods of remission via the use of specifically targeted therapies while minimizing toxicity and promoting normal growth and development. Although systemic corticosteroids are effective in inducing clinical remission, they are of little or no benefit in maintaining remission and can contribute to linear growth retardation. Immunomodulating drugs such as azathioprine, 6‐mercaptopurine and methotrexate have proved effective for inducing and maintaining remission of active Crohn disease. These agents are now commonly prescribed in children at diagnosis, after a severe attack or after surgery or in those who become corticosteroid‐dependent or corticosteroid‐resistant. Their use is not without potential adverse effects and not all patients respond well to these agents. With the introduction of biologic agents, notably the tumor necrosis factor‐α monoclonal antibody infliximab, progress has been made in targeting specific pathogenetic mechanisms of Crohn disease and potentially altering the underlying disease process. Published experience in children is currently limited, but infliximab has been shown to improve symptoms and achieve corticosteroid independence in this age group. Unresolved issues with infliximab and other emerging biologic agents, including long‐term safety, necessitate a degree of caution in selecting appropriate patients for treatment and with careful monitoring of their effects. The collection of contemporary natural history data is crucial to facilitate the better integration of current and emerging therapies in an attempt to alter the natural history of Crohn disease in children.
Efficacy and Safety of Lansoprazole in Adolescents with Symptomatic Erosive and Non‐erosive Gastroesophageal Reflux Disease
Authors: Fiedorek Stephen , Tolia Vasundhara , Gold Benjamin D , Huang Bidan , Stolle Julie , Lee Chang , Gremse David 
Published: February 2005

ABSTRACTObjectives:To assess the efficacy and safety of lansoprazole in the treatment of adolescents with symptomatic, endoscopically proven, non‐erosive gastroesophageal reflux disease and erosive esophagitis.Methods:Adolescents between 12 and 17 years of age with esophagitis were enrolled in this open‐label trial and treated with lansoprazole 15 mg (non‐erosive) or 30 mg (erosive) once daily for 8 weeks. If unhealed at week 8, those with erosive esophagitis were treated with an additional 4 weeks of lansoprazole 30 mg once daily.Results:Lansoprazole produced a significant reduction from baseline in the median percentage of days with reflux symptoms (91 to 43% in the 64 adolescents with non‐erosive disease and 85 to 16% in the 23 adolescents with erosive esophagitis, P ≤ 0.001 for each comparison). At week 8, mucosal healing had occurred in 95% (21 of 22) of those with erosive esophagitis. Treatment‐related adverse events were reported by 19% of patients with non‐erosive and 4% of patients with erosive esophagitis. Headache (7%), abdominal pain (5%), nausea (3%) and dizziness (3%) were the most frequently reported adverse events. One patient discontinued treatment early because of dizziness and vomiting. An elevation in mean serum gastrin from baseline (59 pg/mL at pretreatment to 80 pg/mL at final visit) was observed.Conclusion:Lansoprazole 15 mg or 30 mg once daily reduced symptoms of gastroesophageal reflux in adolescents with non‐erosive gastroesophageal reflux disease and erosive esophagitis, respectively. Lansoprazole 30 mg once daily for 8 weeks was effective in healing erosive esophagitis. Both treatment regimens were considered safe.
Dipole Modeling of Epileptic Spikes Can Be Accurate or Misleading
Authors: Kobayashi Katsuhiro , Yoshinaga Harumi , Ohtsuka Yoko , Gotman Jean 
Published: February 2005

Summary:  Purpose: We investigated the accuracy and potential for serious error when representing cortical generators of epileptic spikes with the common single‐dipole model. Spike generators were realistically simulated with cortical areas of different extents. Methods: The source was simulated by using a patch that comprised small triangles on the cortical surface, each triangle having an elementary dipole generator with a moment corresponding to real intracerebral fields of spikes. The source‐patch covered various clinically important parts of the temporal and frontal lobes, with an area ranging from 6 to 120 cm2. The scalp field was computed for each source‐patch by using a realistic head model and was fitted by the single‐dipole model to determine the best‐fit dipole and the intracerebral distribution of residual variance (RV). Dipole modeling also was performed for the simulated scalp field with additional real EEG background. Results: The RV after fitting a dipole to the scalp field without noise was at most 1.34%. Scalp spikes arising from sources of 6 cm2 were of small amplitude, and the dipoles estimated for these spikes were inconsistent. Extension of the source area was associated with increase of scalp potential amplitude, only very small increase of RV, and increased consistency of the estimated dipoles. When the source was very large, the dipoles clustered at very misleading locations. Conclusions: Pitfalls in dipole source localization are caused by the procedure of fitting the simplistic dipole model to real cortical sources with spatial extent and complex configuration.
Increased Seizure Susceptibility of the Hippocampus Compared with the Neocortex of the Immature Mouse Brain in vitro
Authors: Abdelmalik Peter A. , Burnham W. McIntyre , Carlen Peter L. 
Published: February 2005

Summary:  Purpose: The temporal lobe seems particularly susceptible to seizure activity. Mesial temporal lobe structures, including the hippocampus, have the lowest seizure thresholds in the brain. Conversely, thresholds in the frontal neocortex are significantly higher. The development of intact, isolated preparations of hippocampus and neocortex in vitro allows for study into mechanisms governing seizure threshold. Methods: Epileptiform discharges in isolated mouse neocortical blocks were compared with the contralateral intact hippocampus, isolated from the same brain, by using the low‐Mg2+, 4 aminopyridine (4‐AP), and low‐Ca2+ in vitro seizure models. The pharmacology of low Mg2+–induced ictal‐like events (ILEs) generated in the hippocampus and neocortex was then compared by using glutamatergic antagonists dl‐2‐amino‐5‐phosphonovaleric acid (APV) and 6‐cyano‐7‐nitro‐quinoxaline‐2,3‐dione (CNQX), and the Ca2+ channel antagonist, nifedipine. Results: Neocortical blocks generated both recurrent, spontaneous ILEs and interictal‐like events under low‐Mg2+ artificial CSF (aCSF) perfusion, distinct from those generated in the hippocampus. ILEs from the hippocampus displayed lower thresholds and longer durations as compared with isolated neocortical blocks. Similar results were obtained during 4‐AP perfusion. Perfusion with low‐Ca2+ ACSF did not produce stereotypical ILEs in the neocortical block, producing instead recurrent, slow depolarizations. Both ILEs and recurrent, slow depolarizations were produced in the hippocampus. Application of APV and nifedipine exacerbated low Mg2+–induced ILEs in the hippocampus but not the neocortex, indicating a distinct pharmacology for partial seizures of different brain regions. Conclusions: The developing mouse hippocampus demonstrates increased ictogenesis compared with the developing neocortex in vitro, consistent with clinical observations and in vivo experimental models.
A medication screening trial evaluation of reserpine, gabapentin and lamotrigine pharmacotherapy of cocaine dependence
Authors: Berger S. Paul , Winhusen Theresa M. , Somoza Eugene C. , Harrer Judy M. , Mezinskis Juris P. , Leiderman Deborah B. , Montgomery Margaret A. , Goldsmith R. Jeffrey , Bloch Daniel A. , Singal Bonita M. , Elkashef Ahmed 
Published: February 2005

ABSTRACTAims  To conduct a preliminary evaluation of the safety and efficacy of reserpine, gabapentin or lamotrigine versus an unmatched placebo control as a treatment for cocaine dependence.Design  A 10‐week out‐patient study using the Cocaine Rapid Efficacy and Safety Trial (CREST) study design.Setting  The study was conducted at the Cincinnati Medication Development Research Unit (MDRU).Participants  Participants met Diagnostic and Statistical Manual version IV (DSM‐IV) criteria for cocaine dependence. Sixty participants were enrolled, with 50 participants completing the final study measures.Intervention  The targeted daily doses of medication were reserpine 0.5 mg, gabapentin 1800 mg and lamotrigine 150 mg. All participants received 1 hour of manualized individual cognitive behavioral therapy on a weekly basis.Measurements  Primary outcome measures of efficacy included urine benzoylecgonine (BE) level, Cocaine Clinical Global Impression scale—observer and self‐report of cocaine use. Safety measures included adverse events, electrocardiograms (ECGs), vital signs and laboratory tests.Findings  Subjective measures of cocaine dependence indicated significant improvement for all study groups. Urine BE results indicated a significant improvement for the reserpine group (P < 0.05) and non‐significant changes for the other study groups. No pattern of physical or laboratory abnormalities attributable to treatment with any of the medications was identified. There were three serious adverse events reported, none of which were related to study procedures. The medications appeared to be tolerated well.Conclusions  The present findings suggest that reserpine may be worthy of further study as a cocaine dependence treatment.
The value of an acute octreotide suppression test in predicting long‐term responses to depot somatostatin analogues in patients with active acromegaly
Authors: Karavitaki Niki , Botusan Ileana , Radian Serban , Coculescu Mihail , Turner Helen E. , Wass John A. H. 
Published: February 2005

SummaryBackground  The long‐acting depot somatostatin analogues [octreotide LAR (LAR) and lanreotide (LAN)] are among the most effective available medical therapies for acromegaly. However, published data on a biochemical test suitable for predicting the responsiveness to these depot agents are lacking.Aim  To investigate the value of an acute octreotide suppression test (OST) in predicting the responses to treatment with long‐acting somatostatin analogues in patients with active acromegaly.Patients and Methods  Thirty patients with active acromegaly [mean GH in GH day curve (GHDC) > 5 mU/l] were subjected to an OST [hourly GH measurements for 6 h following 100 µg subcutaneous (s.c.) octreotide]. Subsequently, 14 patients were treated with LAR, 10 with LAN and 6 received both drugs at different times. The final response to treatment was evaluated when the subjects had achieved ‘safe’ GH levels (mean GH < 5 mU/l) or after receiving the maximal dose of each drug (maximum duration of treatment 6 months).Results  The nadir GH values during the OST were 2·6 ± 2·5 mU/l (mean ± SD, range 0·2–8·7) with a percentage fall of 84·8 ± 15·7% (mean ± SD, range 26–99%) from the baseline levels (26·2 ± 31·5 mU/l, mean ± SD). All the patients except one showed a decrease of greater than 50%. The mean time to achieve the nadir GH value was 3·8 ± 1·6 h (mean ± SD, range 1–6). The nadir GH levels showed a positive correlation with both pre‐treatment (i.e. before commencing LAN or LAR) GH values during the GHDC (r = 0·63, P < 0·01) and IGF‐I levels (r = 0·56, P < 0·05). The nadir GH values during the OST showed a positive correlation with the achieved mean GH levels in patients treated with LAR (r = 0·66, P < 0·01) but not in the ones treated with LAN. The criterion of GH < 5·25 mU/l during the OST had sensitivity 100%, specificity 80%, positive predictive value (PPV) 94% and negative predictive value (NPV) 100% in predicting achievement of ‘safe’ GH levels in patients treated with LAR. A less optimal prognostic profile was obtained for subjects treated with LAN with the criterion of GH < 6·05 mU/l during the OST providing sensitivity 92%, specificity 67%, PPV 92% and NPV 67%. The above cut‐off GH levels had a PPV of only 77% and 60% in predicting normalization of IGF‐I on treatment with LAR or LAN, respectively.Conclusions  The OST is a reliable tool for the selection of patients with active acromegaly who will achieve ‘safe’ GH levels on therapy with LAR. Its prognostic profile is less optimal for patients treated with LAN. If GH values during the test fall < 5·25 mU/l (in case of LAR treatment) or < 6·05 mU/l (in case of LAN treatment), there is a 92–94% chance of subsequently achieving ‘safe’ GH levels after up to 6 months treatment with either of these agents.