bluuebunny/crossref_metadata_2025 huggingface dataset:
Organic solvent tolerance of Halobacterium sp. SP1(1) and its extracellular protease
Authors: Akolkar Aparna V. , Deshpande Gauravi M. , Raval Kandarp N. , Durai Deepa , Nerurkar Anuradha S. , Desai Anjana J.
Published: August 2008

Halophilic archaea belonging to three different genera‐ Halobacterium, Haloarcula and Haloferax, were isolated from Kandla salt pans. The isolates had an optimum requirement of 25% NaCl for growth. Increase in organic solvent tolerance of isolates was observed at higher NaCl concentrations. Among the three isolates Halobacterium sp. SP1(1) was found to be more tolerant than Haloarcula sp. SP2(2) and Haloferax sp. SP1(2a). The extracellular protease of Halobacterium sp. SP1(1) showed higher solvent tolerance compared to the organism itself. The enzyme was highly tolerant to toluene, xylene, n‐decane, n‐dodecane and n‐undecane, majority of which are frequently used in paints. These findings may help in understanding the mechanism of organic solvent tolerance in halophilic archaea and their application in antifouling coatings. Also, best to our knowledge the present study is the first report on organic solvent tolerance of haloarchaeal extracellular protease. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐dimensional fractal growth properties of the filamentous fungus Cryphonectria parasitica: the effects of hypovirus infection
Authors: Golinski Michael R. , Boecklen William J. , Dawe Angus L.
Published: August 2008

Whole‐colony two‐dimensional fractal growth patterns produced by hypovirus‐infected Cryphonectria parasitica (EP155/CHV1‐EP713) were measured and compared with those produced by the isogenic virus‐free strain (EP155) on solid medium. We have quantified statistically significant differences in the rates of expansion and spatial dynamics of colony growth between the two strains and concluded that fractal dimension is affected by the presence of the hypovirus. Therefore, fractal dimension measurement is an effective quantitative tool for testing the effects of mycovirus infection on fungal growth parameters. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diversity of auxin‐producing bacteria associated to Pseudomonas savastanoi ‐induced olive knots
Authors: Ouzari Hadda , Khsairi Amel , Raddadi Noura , Jaoua Leila , Hassen Abdennaceur , Zarrouk Mokhtar , Daffonchio Daniele , Boudabous Abdellatif
Published: August 2008

Forty three strains were isolated from knots induced by Pseudomonas savastanoi in different olive cultivars. All the selected bacteria were shown to produce variable amounts of the plant growth hormone indole‐3‐acetic acid (IAA). Amplification of the intergenic transcribed spacers (ITS) between 16S and 23S rDNA genes, allowed the clustering of the isolates into seven distinct groups. All isolates from ITS group 1 were positive to the Pseudomonas savastanoi pv. savastanoi specific iaa L gene as shown by PCR. Partial sequencing of 16S rDNA gene confirmed the identity of these isolates to Pseudomonas savastanoi strains and allowed to tentatively assign the other isolates from the remaining ITS groups to Pantoea oleae/agglomerans, Burkholderia cepacia, Pseudomonas putida, Stenotrophomonas maltophilia and Hafnia alvei. Identification of endophytic knot‐derived isolates revealed association of various saprophytic and putative human pathogenic bacteria with P. savastanoi pv. savastanoi in knot environment of olive infected trees. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rheological properties of yeasted and nonyeasted wheat doughs developed under different mixing conditions
Authors: Connelly Robin K , McIntier Rebekah L
Published: August 2008

BACKGROUND: In order to explore the differences in rheological behaviour of full formula and flour/water doughs due to mixing, small‐amplitude oscillatory strain (SAOS) rheological measurements were made on fully developed nonyeasted and inactivated yeasted dough formulations mixed at various speeds using the Brabender Farinograph and the Bohlin ReoMixer. These results were compared with large‐strain empirical rheological results (including Kieffer rig uniaxial extension) as well as baking test results to determine differences due to mixer speed and/or flow distribution.

RESULTS: The uniaxial extension and baking tests detected mixing speeds with incomplete dough development. Above those speeds, energy input to peak development was relatively constant in the Farinograph. Extensibility trends showed increases with speed in the yeasted dough samples, which were attributed to variation in fermentation time during mixing to peak torque at different speeds. While SAOS results did not show differences due to mixing speed, they did detect differences between the yeasted and nonyeasted dough formulations, as well as significant differences (P < 0.01) between yeasted doughs mixed in the two different mixers.

CONCLUSION: The results indicate that known differences in the distribution of elongational and shear flows in the two mixers impact the development of dough structure during mixing. Copyright © 2008 Society of Chemical Industry
Mutuality of the marital relationship in Parkinson's disease
Authors: Tanji Haruko , Anderson Karen E. , Gruber‐Baldini Ann L. , Fishman Paul S. , Reich Stephen G. , Weiner William J. , Shulman Lisa M.
Published: August 2008

To assess the association between mutuality of the marital relationship in Parkinson's disease with disease severity, disability, mental health, quality of life, and caregiver burden. Spouses of patients with PD completed questionnaires assessing mutuality of the marital relationship (Mutuality Scale) and caregiver strain (Caregiver Strain Index). Patients and spouses completed scales assessing their mental health (Brief Symptom Inventory‐18), medical co‐morbidity (Cumulative Illness Rating Scale) and health‐related QoL (SF‐12v2). PD severity and disability were assessed with the Unified Parkinson's Disease Rating Scale and the Older Americans Resource and Services Disability Scale. The relationships between mutuality and patient and spousal variables were analyzed with univariate correlations and multiple regression. Ninety‐six spouse‐patient pairs were assessed. Increased mutuality, as reported by the spouse was associated with reduced caregiver burden, less depression of both spouse and patient, and less PD severity. Mutuality was inversely correlated with gait impairment, with lesser correlations for balance, urinary incontinence and motor fluctuations. Greater mutuality between spouses and patients with PD is associated with better mental health of both partners, reduced caregiver burden and improved spousal quality of life. PD severity, especially gait, balance, urinary incontinence and motor fluctuations are particular stressors on the marital relationship. © 2008 Movement Disorder Society
[123I]FP‐CIT SPET imaging in drug‐induced Parkinsonism
Authors: Tinazzi Michele , Ottaviani Sarah , Isaias Ioannis U. , Pasquin Isabella , Steinmayr Maria , Vampini Claudio , Pilleri Manuela , Moretto Giuseppe , Fiaschi Antonio , Smania Nicola , Giorgetti Piergiorgio , Antonini Angelo
Published: August 2008

We assessed the status of dopamine nerve terminals in patients treated with dopamine receptor blocking agents (DRBAs) who had developed drug‐induced parkinsonism (DIP). We performed [123I]FP‐CIT SPET in 32 consecutive patients who were on DRBAs for at least 6 months and developed extrapyramidal signs. The UPDRS‐III was used to assess clinical severity. Twenty‐six age‐ and sex‐matched healthy subjects served as control group. Putamen [123I]FP‐CIT SPET binding was reduced in 14 and normal in the remaining 18 patients. There was no difference between the two groups for age, duration of DRBAs treatment, UPDRS III, tremor, rigidity, and bradykinesia subscores for upper and lower limbs. Conversely, symmetry of parkinsonian signs and presence bucco‐linguo‐masticatory dyskinesias were more frequent in individuals with normal tracer binding. Imaging of the dopamine transporter may help to identify subjects with DIP secondary to a loss of dopamine nerve terminals. © 2008 Movement Disorder Society
Pain and denture condition in edentulous orodyskinesia: Comparisons with tardive dyskinesia and control subjects
Authors: Blanchet Pierre J. , Popovici Romana , Guitard Francine , Rompré Pierre H. , Lamarche Claude , Lavigne Gilles J.
Published: August 2008

Edentulous orodyskinesia (ED) is a neglected source of aimless oral movements that may be confused with tardive dyskinesia (TD). We attempted to clarify the clinical features, significance, and orodental factors in relation to ED. Fourteen ED subjects, 13 TD patients, and 15 age‐matched controls self‐assessed their oral pain perception, condition, and function using a visual analogue scale. Dyskinesias were classified and rated by a neurologist. Perioral thermal and pressure pain threshold studies, and a standardized orodental examination, were conducted blind to subject group. The perceived oral pain level was low in all groups, and those reporting a significant intensity level of pain (≥50th percentile) were few. The pain thresholds in both dyskinetic groups were comparable to control values. All ED cases wore a complete set of dentures, considered a current source of problems by 85.7% of them. ED cases commonly displayed inadequate dental occlusal relationship (P = 0.014 vs. controls; P = 0.036 vs. TD) and an overclosed vertical dimension (P = 0.006 vs. controls) as well as unstable and unretentive dentures. ED was limited to the oral region, spared the tongue when the mouth is open, and was never severe in our patients. ED has distinct movement characteristics and is often associated with inadequate dentures and biomechanical sources of denture instability. The contribution of the foregoing findings to the expression of oral dyskinesia warrants further studies. © 2008 Movement Disorder Society
A comparative study of odor identification and odor discrimination deficits in Parkinson's disease
Authors: Boesveldt Sanne , Verbaan Dagmar , Knol Dirk L. , Visser Martine , van Rooden Stephanie M. , van Hilten Jacobus J. , Berendse Henk W.
Published: August 2008

The aim of this study was to compare the characteristics of odor discrimination and odor identification deficits in a large population of patients with Parkinson's disease (PD) and to determine which of these olfactory tests best distinguishes between patients with PD and control subjects. Olfactory performance was assessed in 404 patients with PD and 150 controls, using the odor identification and discrimination parts of the Sniffin' Sticks battery. Mean identification and discrimination scores in patients with PD were significantly lower than in controls. Linear regression analysis using a 95% confidence interval revealed that, relative to the performance of controls, 65.0% of patients with PD had an impairment in odor identification, whereas 42.1% of patients were impaired on the odor discrimination task. ROC curves revealed a higher sensitivity and specificity for odor identification than for odor discrimination in separating patients from controls. In patients with PD, odor discrimination performance decreased with increasing disease duration, whereas odor identification was not correlated with disease stage or duration. In PD, odor identification is more frequently impaired than odor discrimination and allows a better discrimination between patients and controls. Although an odor identification deficit is generally believed to be independent of disease progression, the impairment in odor discrimination appears to increase with disease duration. © 2008 Movement Disorder Society
Medical decision‐making capacity in cognitively impaired Parkinson's disease patients without dementia
Authors: Martin Roy C. , Okonkwo Ozioma C. , Hill Joni , Griffith H. Randall , Triebel Kristen , Bartolucci Alfred , Nicholas Anthony P. , Watts Ray L. , Stover Natividad , Harrell Lindy E. , Clark David , Marson Daniel C.
Published: August 2008

Little is currently known about the higher order functional skills of patients with Parkinson disease and cognitive impairment. Medical decision‐making capacity (MDC) was assessed in patients with Parkinson's disease (PD) with cognitive impairment and dementia. Participants were 16 patients with PD and cognitive impairment without dementia (PD‐CIND), 16 patients with PD dementia (PDD), and 22 healthy older adults. All participants were administered the Capacity to Consent to Treatment Instrument (CCTI), a standardized capacity instrument assessing MDC under five different consent standards. Parametric and nonparametric statistical analyses were utilized to examine capacity performance on the consent standards. In addition, capacity outcomes (capable, marginally capable, or incapable outcomes) on the standards were identified for the two patient groups. Relative to controls, PD‐CIND patients demonstrated significant impairment on the understanding treatment consent standard, clinically the most stringent CCTI standard. Relative to controls and PD‐CIND patients, PDD patients were impaired on the three clinical standards of understanding, reasoning, and appreciation. The findings suggest that impairment in decisional capacity is already present in cognitively impaired patients with PD without dementia and increases as these patients develop dementia. Clinicians and researchers should carefully assess decisional capacity in all patients with PD with cognitive impairment. © 2008 Movement Disorder Society
Detection of Parkinson's disease by MRI: Spin‐lattice distribution imaging
Authors: Hutchinson Michael , Raff Ulrich
Published: August 2008

We have developed an advanced MRI technique for detecting Parkinson's Disease (PD) which depends on an image constructed as a ratio of images from two inversion recovery sequences (one generating a white matter suppressed image, the other a gray matter suppressed image). This technique was designed to be exceptionally sensitive to the spin‐lattice relaxation time T1. It was refined with the introduction of segmentation analysis and given the acronym SIRRIM (Segmented Inversion Recovery Ratio Imaging). Our objectives are, first, to reinvestigate the sensitivity of MRI with new subjects and second, to investigate whether a new form of analysis, using the gray level distribution of signal in the image, may prove more sensitive than SIRRIM. For each subject, a ratio image was constructed (WMS/GMS) and the substantia nigra segmented out to be displayed as an isolated structure. From the segmented image a measure of disease severity, the Radiological Index (RI), was calculated for each subject. Since the pixel value in the ratio image is a strong function of the local T1 relaxation time, the distribution of pixel values gives the distribution of spin‐lattice relaxation times. A refinement in the analysis is introduced, the Spin‐Lattice Distribution Index (SI), which is an automated measure of MRI signal in the Substantia Nigra pars compacta (SNC). Both RI and SI were calculated for each of 24 subjects, 12 patients and 12 controls. The SI may further improve the separation of patient and control groups, and may therefore be more sensitive than the RI. Unlike the RI it is completely automatic and circumvents two of the limitations of the RI. The work is consistent with the proposition that MRI, when properly configured, is a highly sensitive marker for PD. © 2008 Movement Disorder Society
MR‐spectroscopic findings in juvenile‐onset Huntington's disease
Authors: Reynolds Norman C. , Prost Robert W. , Mark Leighton P. , Joseph Suja A.
Published: August 2008

Seven HD gene positive individuals under the age of 21 years are described with clinical examination and proton‐MR‐spectroscopy (1H‐MRS) profiles of the putamen. Despite clinical variability, the predominate 1H‐MRS abnormality is elevated glutamate, expressed well beyond the confines of the basal ganglia, and low striatal creatine. © 2008 Movement Disorder Society
Predictors of progression in patients with Friedreich ataxia
Authors: La Pean Alison , Jeffries Neal , Grow Chelsea , Ravina Bernard , Di Prospero Nicholas A.
Published: August 2008

Friedreich ataxia is an inherited, progressive, neurodegenerative disorder that is clinically heterogeneous. It is caused by a trinucleotide (GAA) repeat expansion resulting in frataxin loss and oxidative stress. We assessed clinical features including the development of cardiomyopathy and scoliosis and disease progression including loss of ambulation and interference with activities of daily living relative to the length of the GAA repeat, age of onset, and age of diagnosis in a retrospective cohort study of 61 genetically confirmed patients. The use of antioxidants such as vitamins, dietary supplements, and idebenone was also examined. Linear regression and Cox proportional hazard models assessed predictors to disease milestones. The shorter GAA allele accounted for part of the variability in the age of diagnosis (46%) and less in the age of onset (27%). Multivariate analysis demonstrated that age at diagnosis, which may incorporate other genetic and environmental factors, is more important than GAA length in predicting cardiomyopathy, scoliosis, and disease progression. © 2008 Movement Disorder Society
Balance self‐efficacy determines walking capacity in people with Parkinson's disease
Authors: Mak Margaret K.Y. , Pang Marco Y.C.
Published: August 2008

This study aimed to examine the contribution of balance self‐efficacy to walking capacity in patients with Parkinson's disease (PD). Seventy‐one patients with PD and 55 healthy subjects completed the study. Walking capacity was quantified by 6‐min walk (6MW) test. Perceived balance self‐efficacy was assessed by activities‐specific balance confidence (ABC) scale. PD‐specific motor impairments were determined by Unified PD rating scale (Motor Examination III) and maximum muscle strength of lower extremities. Patients with PD achieved significantly shorter 6MW distance and lower ABC score than control subjects (P < 0.001). In multiple regression analysis, after accounting for basic demographics and PD‐specific motor impairments, ABC score remained independently associated with 6MW distance, accounting for 17.1% of the variance (P < 0.001). This is the first study demonstrating that balance self‐efficacy is an important and independent determinant of functional walking capacity in patients with PD. Improving balance confidence could be crucial in promoting walking capacity in PD population. © 2008 Movement Disorder Society
Predictive value of nigrostriatal dysfunction in isolated tremor: A clinical and SPECT study
Authors: Ceravolo Roberto , Antonini Angelo , Volterrani Duccio , Rossi Carlo , Kiferle Lorenzo , Frosini Daniela , Lucetti Claudio , Isaias Ioannis U. , Benti Riccardo , Murri Luigi , Bonuccelli Ubaldo
Published: August 2008

The overlap among tremor disorders is wide and complex because essential tremor patients may present resting tremor coexisting with postural tremor, while postural may coexist with resting tremor in Parkinson's disease. We investigated dopamine transporter binding in 61 subjects presenting with isolated atypical tremors defined as unilateral either postural, resting, or mixed (i.e. resting and postural) tremor, without rigidity or bradykinesia, by means of 123I‐FPCIT SPECT imaging at baseline. Patients were followed‐up clinically for 28.4 ± 7.2 months. Twenty‐five patients with baseline normal SPECT continued to present only tremor at follow‐up. Among 36 patients with abnormal SPECT, 23 (64%) developed PD, while the remaining 13 continued to present only tremor at follow‐up. The value of 123I‐FPCIT SPECT in predicting the evolution to PD was very high in a way independent from the first clinical presentation of tremor (Rest tremor, P = 0.015; Mixed tremor, P = 0.015; Postural tremor, P = 0.039; chi‐square test). Our data suggest that the clinical presentation of isolated tremors is insufficient to allow a precise early‐stage diagnosis, whereas the detection of presynaptic nigrostriatal dopaminergic dysfunction could lead to diagnosis of atypical tremor disorders at a very early stage. We suggest this disorder to be labeled as “isolated tremor with dopaminergic presynaptic dysfunction.” © 2008 Movement Disorder Society
Electrophysiological features of myoclonus‐dystonia
Authors: Li Jie‐Yuan , Cunic Danny I. , Paradiso Guillermo , Gunraj Carolyn , Pal Pramod K. , Lang Anthony E. , Chen Robert
Published: August 2008

Inherited myoclonus‐dystonia (M‐D) is an autosomal dominant disorder characterized by myoclonus and dystonia that often improves with alcohol. To examine the electrophysiologic characteristics of M‐D, we studied 6 patients from 4 different families and 9 age‐matched healthy subjects. Neurophysiological studies performed include electromyography (EMG)‐electroencephalography (EEG) polygraphy, jerk‐locked back‐averaged EEG, somatosensory evoked potentials (SEP), long‐latency reflex (LLR) to median and digital nerve stimulation, and transcranial magnetic stimulation studies with short‐interval intracortical inhibition (SICI), intracortical facilitation (ICF), and long‐interval intracortical inhibition (LICI). All 6 patients showed myoclonus and dystonia on clinical examination and EMG testing. The EMG burst durations ranged from 30.4 to 750.6 milliseconds (mean, 101.5 milliseconds). Jerk‐locked back‐averaged EEG failed to reveal any preceding cortical correlates. Median nerve SEP revealed no giant potential. No patients had exaggerated LLR to median or digital nerve stimulation. There was no significant difference in SICI, ICF, and LICI between M‐D patients and normal subjects. Myoclonus in inherited M‐D is likely of subcortical origin. Normal intracortical inhibition and facilitation suggest that the GABAergic circuits in the motor cortex are largely intact and that the mechanisms of myoclonus and dystonia are different from those for cortical myoclonus and other dystonic disorders. © 2008 Movement Disorder Society
Abnormal antisaccades and smooth pursuit eye movements in patients with Wilson's disease
Authors: Leśniak Marcin , Członkowska Anna , Seniów Joanna
Published: August 2008

Neurological symptoms in Wilson's disease (WD) may include oculomotor abnormalities. However, to date, eye movements in WD patients were rarely investigated and the data concerning this issue are sparse. The purpose of this study was to evaluate reflexive and voluntary eye movements in WD patients. We examined horizontal saccadic and smooth pursuit eye movements using infra‐red oculography in 50 WD patients, including 29 neurologically symptomatic (WDn) and 21 asymptomatic ones (WDa), and in 29 healthy controls. We found statistically significant increase in mean antisaccadic latency (378 ms) and in mean antisaccadic error rate (22.5) in the WDn group, when compared with WDa group (317 ms and 9.1, respectively) and controls (318 ms and 9.7, respectively). In contrast, there were no statistically significant differences in mean latency of prosaccades and in size of the gap effect. Patients with neurological manifestations had also abnormal smooth pursuit—increased number of saccadic intrusions (mean: 8.6) and decreased gain (mean: 0.69) comparing with WDa patients (4.1 and 0.83, respectively) and controls (2.2 and 0.91, respectively). The data suggest that WD is associated both with impairment of voluntary control of saccades and with disturbed smooth pursuit eye movements while reflexive saccades seem to be preserved. © 2008 Movement Disorder Society
1H and 13C NMR assignments for four triterpenoid saponins from Albizziae cortex
Authors: Han Li‐Feng , Ma Bai‐Ping , Zhang Hong‐Sheng , Song Xin‐Bo , Gao Xiu‐Mei , Kang Li‐Ping , Xiong Cheng‐Qi , Zhao Yang , Tan Da‐Wei
Published: August 2008

Four triterpenoid saponins were isolated from Albizziae cortex, and a complete assignment of their 1H and 13C NMR spectra was carried out using 1D and 2D NMR (1H1H COSY, HSQC, HMBC, and HSQC–TOCSY) methods. Their 1H NMR assignments were reported for the first time and some of their 13C NMR spectral data reported in literature were corrected. Copyright © 2008 John Wiley & Sons, Ltd.
Delay management in delay‐tolerant networks
Authors: Zheng Qunwei , Hong Xiaoyan , Wang Pu , Tang Lei , Liu Jun
Published: August 2008

In delay‐tolerant networks (DTN), nodes explore various opportunities to connect and communicate with each other. A series of encounters of different nodes will create such opportunities and spread a message among many nodes and eventually deliver to the designated destination. We study one common DTN scenario where the message exchanges happen when nodes meet others at certain locations. In this situation, the success of message delivery and the quality of the delivery depend highly on the likeliness of nodes' encounters and time elapsed between encounters. We study two important qualities of service requirements: the probability of two nodes meeting each other (encounter probability) and the time it takes for two nodes to meet (encounter delay). The key considerations are how nodes pick their next locations (mobility patterns) and the features of the dwell time. In this paper, we will study several mobility patterns, including random movement, and activity agenda based movement. We also study an additional message delivery constraint, i.e., a message will be dropped if not delivered within a limited number of locations visited. We develop mathematical formulas using Markov chain as a main tool. Our work is presented as an illustration through case studies. The methodology applies to mobility models alike and is extendable to real trace analysis. We present numerical results when closed form formulas cannot be acquired. Our results help the management of message delivery for DTN, e.g., in selecting a proper time‐to‐live threshold for a message. Copyright © 2008 John Wiley & Sons, Ltd.
Development and application of reduced‐order modeling procedures for subsurface flow simulation
Authors: Cardoso M. A. , Durlofsky L. J. , Sarma P.
Published: August 2008

The optimization of subsurface flow processes is important for many applications, including oil field operations and the geological storage of carbon dioxide. These optimizations are very demanding computationally due to the large number of flow simulations that must be performed and the typically large dimension of the simulation models. In this work, reduced‐order modeling (ROM) techniques are applied to reduce the simulation time of complex large‐scale subsurface flow models. The procedures all entail proper orthogonal decomposition (POD), in which a high‐fidelity training simulation is run, solution snapshots are stored, and an eigen‐decomposition (SVD) is performed on the resulting data matrix. Additional recently developed ROM techniques are also implemented, including a snapshot clustering procedure and a missing point estimation technique to eliminate rows from the POD basis matrix. The implementation of the ROM procedures into a general‐purpose research simulator is described. Extensive flow simulations involving water injection into a geologically complex 3D oil reservoir model containing 60 000 grid blocks are presented. The various ROM techniques are assessed in terms of their ability to reproduce high‐fidelity simulation results for different well schedules and also in terms of the computational speedups they provide. The numerical solutions demonstrate that the ROM procedures can accurately reproduce the reference simulations and can provide speedups of up to an order of magnitude when compared with a high‐fidelity model simulated using an optimized solver. Copyright © 2008 John Wiley & Sons, Ltd.
Classical and enriched finite element formulations for Bloch‐periodic boundary conditions
Authors: Sukumar N. , Pask J. E.
Published: August 2008

In this paper, classical and enriched finite element (FE) formulations to impose Bloch‐periodic boundary conditions are proposed. Bloch‐periodic boundary conditions arise in the description of wave‐like phenomena in periodic media. We consider the quantum‐mechanical problem in a crystalline solid and derive the weak formulation and matrix equations for the Schrödinger and Poisson equations in a parallelepiped unit cell under Bloch‐periodic and periodic boundary conditions, respectively. For such second‐order problems, these conditions consist of value‐ and derivative‐periodic parts. The value‐periodic part is enforced as an essential boundary condition by construction of a value‐periodic basis, whereas the derivative‐periodic part is enforced as a natural boundary condition in the weak formulation. We show that the resulting matrix equations can be obtained by suitably specifying the connectivity of element matrices in the assembly of the global matrices or by modifying the Neumann matrices via row and column operations. The implementation and accuracy of the new formulation is demonstrated via numerical examples for the three‐dimensional Poisson and Schrödinger equations using classical and enriched (partition‐of‐unity) higher‐order FEs. Copyright © 2008 John Wiley & Sons, Ltd.
On the numerical solution of hyperbolic PDEs with variable space operator
Authors: Ashyralyev Allaberen , Koksal Mehmet Emir
Published: August 2008

The first and second order of accuracy in time and second order of accuracy in the space variables difference schemes for the numerical solution of the initial‐boundary value problem for the multidimensional hyperbolic equation with dependent coefficients are considered. Stability estimates for the solution of these difference schemes and for the first and second order difference derivatives are obtained. Numerical methods are proposed for solving the one‐dimensional hyperbolic partial differential equation. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2009
Effects of γ radiation on fiber‐reinforced polymer concrete
Authors: Martínez‐Barrera Gonzalo , Giraldo Luis F. , López Betty L. , Brostow Witold
Published: August 2008

Composites were made from 30% unsaturated polyester resin + 70% calcium bentonite and marble as aggregates, as well as 0.3 and 0.4 vol% of nylon fibers. The fiber‐containing polymer concretes (PCs) were subjected to 5, 10, 50, and 100 kGy applied radiation doses. The compressive strength values depend on both the fiber concentration and the irradiation dose applied. Moreover, the polyester‐based PCs containing two mineral aggregates, calcium carbonate and marble, have lower compressive strength values than those reported earlier for PCs containing only either silica sand or CaCO3. However, significant improvement of the compressive strain and the compression modulus of elasticity are achieved when nylon fibers are added. Both these properties go symbatically with the radiation dose. Mechanical characteristics can be related to the morphological features observed by scanning electron microscopy. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Physical and mechanical properties of dental nanocomposites composed of aliphatic epoxy resin and epoxidized aromatic hyperbranched polymers
Authors: Zhang Yujie , Zhang Daohong , Qin Chuangye , Xu Jingwei
Published: August 2008

Aliphatic epoxy resin (UVR6105) and epoxidized aromatic hyperbranched polymers (HBP) were used as dental resin matrixes, siliane‐treated inorganic nanoparticles as inorganic fillers, ethyl 4‐dimethylaminobenzoate, camphorquinone, and 4‐[(2‐hydroxytetradecyl)oxy] phenyl‐phenyliodoniumhexafluoroantimonate (CD1012) as initiators to formulate new kinds of dental nanocomposites. Their physical and mechanical properties were tested and the inner structure was observed by using scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. The 7 series thermal analysis system was used to determine the glass transition temperature of dental resins. Compressive strengths of dental nanocomposites are lower, diametral tensile strengths are comparable with, flexural strengths are higher than those of commercial hybrid composite (Spectrum‐TPH). The addition of HBP decreased the glass transition temperature of aliphatic epoxy resin. SEM photo micrograph shows that the nanoparticles were well dispersed and inlayed in the resin matrixes. TEM photo micrograph shows that the inner structure of dental resins presents club‐shaped. Epoxidized aromatic hyperbranched polymer can strengthen and toughen aliphatic epoxy resin. These nanocomposites are potential for dental application. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Ins eigene Segel blasen. Münchhausen‐Effekt und Schubumkehr
Authors: Vollmer Michael , Möllmann Klaus‐Peter , Arnold Frank
Published: August 2008

Kann man sich mit seinem Segelboot fortbewegen, indem man ins eigene Segel bläst? Der Impulssatz erlaubt diesen an Münchhausen erinnernden Effekt. Das demonstriert ein vereinfachtes Gedankenexperiment, bei dem der Segler durch den Werfer eines Balls und das Segel durch eine starre Wand ersetzt wird. Allerdings ergibt die naive Theorie, die Luftmoleküle als ballähnliche Korpuskeln auffasst, einen zu hohen Impuls des reflektierten Luftstroms. Eine realistische Beschreibung liefert die moderne Strömungstheorie. Ihre Resultate sind experimentell erfolgreich umsetzbar. Technisch angewendet wird das Prinzip in der Schubumkehr von Flugzeugtriebwerken.
In den eisigen Welten des Saturn. Planetenforschung
Authors: Köhler Ulrich , Stephan Katrin , Wagner Roland
Published: August 2008

Cassini liefert seit vier Jahren wertvolle Experimentdaten aus der Welt des Saturn, seiner Ringe, von den Monden und der kosmischen Umgebung des zweitgrößten Planeten des Sonnensystems. Die Mission ermöglichte wichtige Erkenntnisse über die Prozesse, die im äußeren Sonnensystem seit der Bildung der Planeten abgelaufen sind. Diese Ergebnisse sind in vielerlei Hinsicht auch bedeutend für das Verständnis der Planeten im inneren Sonnensystem. Huygens ist erstmals auf dem Saturnmond Titan gelandet und hat Bilder und Messdaten von einem der interessantesten Körper im Sonnensystem geliefert. Seit dem 1. Juli 2008 befindet sich die Mission Cassini in einer ersten Verlängerungsphase. Bis Mitte 2010 wird die Sonde weitere 60 Mal Saturn umrunden.
Künstlicher Kugelblitz. Leuchtende Plasmabälle im Labor
Authors: Fußmann Gerd
Published: August 2008

Ob Kugelblitze in der Natur existieren, ist bislang unbewiesen. Im Labor lassen sich ähnliche Phänomene produzieren. Besonders interessant sind autonome Objekte, die ohne externe Energiezufuhr leuchten. Derzeit gibt es zwei Methoden, diese im Labor zu erzeugen. Bei einer entstehen Leuchtkugeln aus Silizium‐Aerosol, die bis zu 8 s lang existieren. Sie sind aber klein und schweben nicht, was den meisten Augenzeugenberichten über Kugelblitze widerspricht. Die zweite Methode erzeugt mit Elektroden in einem Wasserbehälter eine Gleitentladung an der Wasseroberfläche. Dabei entsteht ein Plasmoid, das etwa 0,3 s lang exisitert. Diese Kugel ist zunächst bis zu 20 cm groß. Sie steigt auf, verformt sich zu einem Pilz und schließlich zu einem Ring. Ihre Leuchtquelle ist chemische Energie. Solche Experimente können die Existenz von natürlichen Kugelblitzen allerdings noch nicht sicher beweisen.
Kaltes bei Hitze?
Authors: Müller Andreas
Published: August 2008

Es herrscht brütende Hitze, und Sie haben Lust auf ein eiskaltes Getränk. Doch kühlt selbst ein Liter kaltes Wasser (Proteste des Magens werden ignoriert) die Körpertemperatur wirklich merkbar ab?
Funkenüberschlag
Authors: Loos Andreas
Published: August 2008

Frisch promoviert und staatsexaminiert darf er Mathematik, Physik, Chemie und Mineralogie bis zur Obertertia unterrichten. Doch das ist Plan B – eigentlich will er sich habilitieren. Schließlich, so glaubt er von sich, werde er “den Ansprüchen, die man an einen Physiker mittleren Ranges zu stellen berechtigt ist, mit der Zeit genügen.”
Frittierphysik für perfekte Pommes
Authors: Vilgis Thomas
Published: August 2008

Der Ruf von Pommes Frites ist nicht gerade der beste. Mitunter sind sie von Fett durchtränkt, was nicht nur Ernährungsfachleute in Rage versetzt, sondern auch den Genuss deutlich beeinträchtigt. Das eingedrungene Frittierfett verhindert nämlich die wichtigste mechanische Eigenschaft der Fritten: die krachende Knusprigkeit der Hülle und das kartoffelige Innenleben. Mit physikalischer Frittiertheorie lassen sich derartige Unwägbarkeiten verhindern.
No indications of cognitive side‐effects in a prospective study of breast cancer patients receiving adjuvant chemotherapy
Authors: Mehlsen Mimi , Pedersen Anders Degn , Jensen Anders Bonde , Zachariae Robert
Published: August 2008

Objective: A number of cross‐sectional studies have reported reduced cognitive function in cancer patients receiving chemotherapy compared with other cancer patients and healthy controls, suggesting that chemotherapy could be associated with cognitive side‐effects. Recently published prospective studies question this hypothesis, but it is still unclear whether cancer patients should regard cognitive problems as a potential risk when receiving chemotherapy.

Methods: In the present study we examine whether cancer patients (n=34) receiving chemotherapy differed in cognitive changes during treatment compared with cardiac patients (n=12) and healthy controls (n=12) tested at 3–4 months interval.

Results: Our results showed no differences with respect to changes in cognitive performance over time between cancer patients in chemotherapy, cardiac patients, and healthy controls. In addition, the number of individuals showing reliable decline or improvement on cognitive tests did not differ between groups.

Conclusion: Taken together, our results do not support a hypothesis of cognitive side‐effects of standard‐dose chemotherapy in breast cancer patients. Copyright © 2008 John Wiley & Sons, Ltd.
Use of simulation to compare the performance of minimization with stratified blocked randomization
Authors: Toorawa Robert , Adena Michael , Donovan Mark , Jones Steve , Conlon John
Published: August 2008

Minimization is an alternative method to stratified permuted block randomization, which may be more effective at balancing treatments when there are many strata. However, its use in the regulatory setting for industry trials remains controversial, primarily due to the difficulty in interpreting conventional asymptotic statistical tests under restricted methods of treatment allocation. We argue that the use of minimization should be critically evaluated when designing the study for which it is proposed. We demonstrate by example how simulation can be used to investigate whether minimization improves treatment balance compared with stratified randomization, and how much randomness can be incorporated into the minimization before any balance advantage is no longer retained. We also illustrate by example how the performance of the traditional model‐based analysis can be assessed, by comparing the nominal test size with the observed test size over a large number of simulations. We recommend that the assignment probability for the minimization be selected using such simulations. Copyright © 2008 John Wiley & Sons, Ltd.
A limiting distribution for the number of cuts needed to isolate the root of a random recursive tree
Authors: Drmota Michael , Iksanov Alex , Moehle Martin , Roesler Uwe
Published: August 2008

Let Xn be the number of cuts needed to isolate the root in a random recursive tree with n vertices. We provide a weak convergence result for Xn. The basic observation for its proof is that the probability distributions of $\{X_n: n=2,3,\ldots\}$ are recursively defined by $X_n {{\rm d}\atop{=}} X_{n-D_n} + 1, \; n=2,3,\ldots, \; X_1=0$, where Dn is a discrete random variable with ℙ${\{ D_n = k \} = {1 \over {k(k+1)}} {n \over {n-1}}, \; k=1,2,\ldots, n-1}$, which is independent of $(X_2,\ldots, X_n)$. This distributional recursion was not studied previously in the sense of weak convergence. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2009
Local resilience of graphs
Authors: Sudakov Benny , Vu V.H.
Published: August 2008

In this article, we initiate a systematic study of graph resilience. The (local) resilience of a graph G with respect to a property
$\cal {P}$
measures how much one has to change G (locally) to destroy $\cal {P}$. Estimating the resilience leads to many new and challenging problems. Here we focus on random and pseudorandom graphs and prove several sharp results. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008
An efficient method for accommodating potentially underpowered primary endpoints
Authors: Li Jianjun (David) , Mehrotra Devan V.
Published: August 2008

If a trial is adequately powered for two clinically important endpoints, A and B, each of which can fully characterize a treatment benefit to support a regulatory claim by itself, then both endpoints are usually labeled primary, and the trial is deemed positive if either endpoint is statistically significant after a multiplicity adjustment. However, if only A is adequately powered, then should B be designated a secondary endpoint, or should it be retained in the primary family despite being (potentially) underpowered? The former option can lead to a negative trial if A is not statistically significant, no matter how positive the results are for B, since no familywise type I error rate (FWER) is allocated to B, while the latter can reduce the likelihood of a positive trial if an inefficient multiplicity adjustment is used. We underscore this contemporary problem with real examples and offer a novel and intuitively appealing solution for accommodating clinically important but potentially underpowered endpoint(s) in the primary family. In our proposal, for the above scenario with two endpoints, A is tested at a prespecified level α1=α−ε (e.g. ε=0.01 when α=0.05), and B at an ‘adaptive’ level α2 (⩽α) calculated using a prespecified non‐increasing function of the p‐value for A. Our method controls the FWER at level α and can notably increase the probability of achieving a positive trial compared with a fixed prospective alpha allocation scheme (Control. Clin. Trials 2000; 20:40–49), and with Hochberg's method applied to the family of primary endpoints. Importantly, our proposal enables strong results for potentially underpowered primary endpoint(s) to be interpreted in a conclusive rather than exploratory light. Copyright © 2008 John Wiley & Sons, Ltd.
Standardized test outcomes for students engaged in inquiry‐based science curricula in the context of urban reform
Authors: Geier Robert , Blumenfeld Phyllis C. , Marx Ronald W. , Krajcik Joseph S. , Fishman Barry , Soloway Elliot , Clay‐Chambers Juanita
Published: August 2008

Considerable effort has been made over the past decade to address the needs of learners in large urban districts through scaleable reform initiatives. We examine the effects of a multifaceted scaling reform that focuses on supporting standards based science teaching in urban middle schools. The effort was one component of a systemic reform effort in the Detroit Public Schools, and was centered on highly specified and developed project‐based inquiry science units supported by aligned professional development and learning technologies. Two cohorts of 7th and 8th graders that participated in the project units are compared with the remainder of the district population, using results from the high‐stakes state standardized test in science. Both the initial and scaled up cohorts show increases in science content understanding and process skills over their peers, and significantly higher pass rates on the statewide test. The relative gains occur up to a year and a half after participation in the curriculum, and show little attenuation with in the second cohort when scaling occurred and the number of teachers involved increased. The effect of participation in units at different grade levels is independent and cumulative, with higher levels of participation associated with similarly higher achievement scores. Examination of results by gender reveals that the curriculum effort succeeds in reducing the gender gap in achievement experienced by urban African‐American boys. These findings demonstrate that standards‐based, inquiry science curriculum can lead to standardized achievement test gains in historically underserved urban students, when the curriculum is highly specified, developed, and aligned with professional development and administrative support. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 922–939, 2008
Comparison Between Open and Laparoscopic Repair of Perforated Peptic Ulcer Disease
Authors: Bhogal Ricky H. , Athwal Ruvinder , Durkin Damien , Deakin Mark , Cheruvu Chandra N. V.
Published: August 2008

Background

The place of laparoscopic repair of perforated peptic ulcer followed by peritoneal toilet has been established, although it is not routinely practiced. This prospective study compared laparoscopic and open repair of perforated peptic ulcer disease. We evaluated whether the early results from laparoscopic repair resulted in improved patient outcome compared with conventional open repair.

Methods

All patients who underwent repair of perforated peptic ulcer disease during a 12‐month period in our unit were included in the study. The primary end points that were evaluated were total operative time, nasogastric tube utilisation, intravenous fluid requirement, total time of urinary catheter and abdominal drainage usage, time taken to return to normal diet, intravenous/intramuscular opiate use, time to full mobilization, and total in‐patient hospital stay.

Results

Thirty‐three patients underwent surgical repair of perforated peptic ulcer disease (19 laparoscopic repairs and 14 open repairs; mean age, 54.2 (range, 32–82) years). There was no increase in total operative time in patients who had undergone laparoscopic repair (mean: 61 minutes laparoscopic versus 57 minutes open). There was significantly less requirement for intravenous/intramuscular opiate analgesia in patients who had undergone laparoscopic repair (mean time to oral analgesia: 1.2 days laparoscopic versus 3.8 days open). In addition there was a significant decrease in the time that the nasogastric tube (mean: 2.1 days laparoscopic versus 3.1 days open), urinary catheter (mean: 2.3 days laparoscopic versus 3.7 days open) and abdominal drain (mean: 2.2 days laparoscopic versus 3.8 days open) were required during the postoperative period. Patients who had undergone laparoscopic repair required less intravenous fluids (mean: 1.4 days laparoscopic versus 3.1 days open) and returned to normal diet (mean: 2.3 days laparoscopic versus 4.8 days open) and full mobilization significantly earlier than those who had undergone open repair (mean: 2.3 days laparoscopic versus 3.3 days open). In addition, patients who had undergone laparoscopic repair required a shorter in‐patient hospital stay (mean: 3.1 days laparoscopic versus 4.3 days open).

Conclusions

Laparoscopic repair is a viable and safe surgical option for patients with perforated peptic ulcer disease and should be considered for all patients, providing that the necessary expertise is available.
Surgical Education at the West African College of Surgeons
Authors: Bode Christopher Olusanjo , Nwawolo Clement Chukwuemeka , Giwa‐Osagie Osato Frank
Published: August 2008

The West African College of Surgeons (WACS) was formed almost 50 years ago to foster friendship and greater interaction amongst the first crop of surgeons of West African origin freshly returning from overseas training. Under the College’s umbrella, seven different surgical Faculties—Anaesthesiology, Dental Surgery, Obstetrics & Gynaecology, Ophthalmology, Otorhinolaryngology, Radiology/Radiotherapy, and Surgery—have been nurtured into viable entities. The WACS is a leading institution for surgical training, accreditation, and collaboration with international bodies in the subregion. With more than 3000 Fellows, the WACS’ surgical training programs and diplomas have remained the standard format for a population of >140 million in the five Anglophone West African countries for decades. The College has assumed increasing roles in attracting donor agencies as well as West Africans in the Diaspora desirous of establishing training links with credible institutions in the subregion. This paper discusses the history of the WACS, its examination process and other functions, as well as its contributions toward and challenges in surgical manpower development in the West African subregion.