bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of inbred germ-free Fischer 344 albino rats as an experimental model for oral candidiasis
Authors: Van Wyk C. W. , Basson N. J. , Gibson B. M.
Published: May 2007

Inbred germ-free Fischer 344 albino rats were evaluated as models for experimental candidiasis in order to investigate bacterial interaction with Candida albicans. Female rats were exposed to C. albicans in their drinking water and killed at intervals from 2 to 22 days after initial contact with the contaminant. C. albicans was cultured from their mouths from day 2 but from day 12 the number of colonies decreased. From day 2 to 9 all rats showed oral histological signs of candidal infestation, but after 9 days the number declined to 3 out of 9 at 22 days. The dorsal surface of the tongue was the best histological indicator of candidal infestation. All the rats had tongue lesions from day 4 to 9, and from day 6 there was also a concomitant localized loss of filiform papillae. The number of rats with all forms of tongue involvement also decreased after 9 days with only 3 out of 9 affected at 22 days. It is concluded that Fischer 344 inbred germ-free rats can be used on a limited scale as a model for candidiasis and bacterial interaction with C. albicans, the dorsal surface of the tongue would be the best site for studying candidal experimental lesions and it is probable that better results can be achieved with complete standardization of contamination and preparation procedures.
The Adsorption of Phenol, m-Cresol and m-Catechol on a β-Cyclodextrin Derivative-Grafted Chitosan and the Removal of Phenols from Industrial Wastewater
Authors: Chen Qi Yuan , Xiao Jian Bo , Chen Xiao Qing , Jiang Xin Yu , Yu Hong Zhu , Xu Ming
Published: May 2007

A β-cyclodextrin derivative (CCDC) was synthesized with chitosan and carboxymethyl-β-cyclodextrin, and its structure was characterized via elemental analysis, infrared spectral analysis and X-ray diffraction analysis. On addition of DMF to the reaction solution, the degree of substitution by the carboxymethyl-β-cyclodextrin moiety achieved a value of 0.27. The results were in agreement with expectations. The static adsorption properties of CCDC towards phenol, m-cresol and m-catechol were studied. The experimental results demonstrated that CCDC had a higher adsorption capability towards m-catechol than for phenol and m-cresol, with the adsorption capacity for m-catechol being 110.56 mg/g. The adsorption capacity was greatly influenced by the pH, time and temperature. The introduction of chitosan enhanced the adsorption ability and adsorption selectivity of β-cyclodextrin towards m-catechol. This novel chitosan derivative demonstrated high percentage removal of phenols from wastewater.
Characterization of Manganese/Molybdenum Mixed Oxides
Authors: Zahran Afaf
Published: May 2007

Samples of manganese oxide (Mn3O4) were prepared from MnCl2 solutions of different concentrations (0.025, 0.05, 0.10 and 0.50 N) via precipitation using NH4OH aqueous solution. Although similar in chemical structure, the samples obtained showed different textures corresponding to the calcination temperature employed up to 900°C. Loading these samples with different amounts of Mo followed by calcination at 900°C led to the formation of MnMoO4 samples displaying variable modes of dispersion on their surfaces. The variable distribution of surface hydroxy groups on the samples due to their different textures caused changes in the manner in which the Mo species and the manganese oxide surface interacted, and consequently the final state of the samples obtained after calcination at 900°C differed. Stabilization of the initially formed hausmannite was only detected for Mo-loaded samples prepared from a 0.025 N solution and calcined at 900°C. This behaviour was not observed in the case of the other three samples studied. This stabilization is attributed to localized growth of MnMoO4 that caused the under-layer regions to be subjected to different environmental conditions during the calcination/cooling processes.
Approximation Algorithms for Stochastic Inventory Control Models
Authors: Levi Retsef , Pál Martin , Roundy Robin O. , Shmoys David B.
Published: May 2007

We consider two classical stochastic inventory control models, the periodic-review stochastic inventory control problem and the stochastic lot-sizing problem. The goal is to coordinate a sequence of orders of a single commodity, aiming to supply stochastic demands over a discrete, finite horizon with minimum expected overall ordering, holding, and backlogging costs. In this paper, we address the important problem of finding computationally efficient and provably good inventory control policies for these models in the presence of correlated, nonstationary (time-dependent), and evolving stochastic demands. This problem arises in many domains and has many practical applications in supply chain management.

Our approach is based on a new marginal cost accounting scheme for stochastic inventory control models combined with novel cost-balancing techniques. Specifically, in each period, we balance the expected cost of overordering (i.e., costs incurred by excess inventory) against the expected cost of underordering (i.e., costs incurred by not satisfying demand on time). This leads to what we believe to be the first computationally efficient policies with constant worst-case performance guarantees for a general class of important stochastic inventory control models. That is, there exists a constant C such that, for any instance of the problem, the expected cost of the policy is at most C times the expected cost of an optimal policy. In particular, we provide a worst-case guarantee of two for the periodic-review stochastic inventory control problem and a worst-case guarantee of three for the stochastic lot-sizing problem. Our results are valid for all of the currently known approaches in the literature to model correlation and nonstationarity of demands over time.
Use of Histamine2-Antagonists for the Treatment of Verruca Vulgaris
Authors: Fit Kathy E , Williams Patrick C
Published: May 2007

Objective:

To review the evidence for histamine2 (H2)-antagonists in the treatment of common warts.

Data Sources:

Relevant publications were identified through a systematic search of PubMed English-language literature using the MeSH terms and key words cimetidine, ranitidine, famotidine, nizatidine, histamine H2-antagonists, and warts. Additional articles were identified using the same key words in the Cochrane Database and International Pharmaceutical Abstracts. Systematic searches were conducted through January 2007. In addition, pertinent references from identified articles were reviewed.

Study Selection and Data Extraction:

The literature search retrieved 21 relevant citations, excluding review articles. Five open-label studies and 7 randomized controlled clinical trials were evaluated. Cimetidine was the focus of 11 studies, and ranitidine was evaluated in 1 study. No data regarding the other H2-antagonists were found. The other retrieved citations were not evaluated due to their design (case reports or case series) and/or focus on specific wart subtypes, not common warts.

Data Synthesis:

The use of H2-antagonists in the treatment of common warts is not associated with significant improvements in resolution rates. Open-label studies were promising with an estimated 48–81% response rate. However, randomized controlled trials have failed to show significant efficacy when cimetidine was compared with placebo or topical agents, and ranitidine has never been evaluated in a randomized controlled trial. Adverse effects, specifically gastrointestinal complaints, were documented. Efficacy may have been limited by inadequate dosing in some of the trials. The studies were limited by the small sample size and lack of power in a number of the trials, as well as the documented spontaneous resolution rate for warts.

Conclusions:

Several open-label trials evaluating the use of H2-antagonists for verruca vulgaris reported high response rates, but these results have not been corroborated by more rigorous clinical trials. Current data do not support the use of H2-antagonisis for the treatment of common warts.
Exogenous Cushing Syndrome with Inhaled Fluticasone in a Child Receiving Lopinavir/Ritonavir
Authors: Bhumbra Nasreen A , Sahloff Eric G , Oehrtman Sandra J , Horner James M
Published: May 2007

Objective:

To describe a case of Cushing syndrome in a child during concurrent use of inhaled fluticasone propionate, nasal mometasone, and a highly active antiretroviral regimen including lopinavir/ritonavir.

Case Summary:

A 9-year-old boy with HIV infection and asthma developed moon fades, increased facial hair, and increased weight after fluticasone propionate inhalation (1 puff; 220 μg) therapy was begun. His antiretroviraI regimen contained the protease inhibitor combination lopinavir/ritonavir at a dose of 216/54 mg twice daily, and he had been stable for the previous 5 years. He had also been receiving intranasal mometasone for 11 months for the management of allergic rhinitis. Serum Cortisol and adrenocorticotropic hormone levels were consistent with adrenal suppression, These physical findings and symptoms and laboratory values normalized after discontinuation of the fluticasone propionate. The Naranjo probability scale indicated that a probable interaction occurred between lopinavir/ritonavir and fluticasone propionate, loading to subsequent adrenal suppression.

Discussion:

Protease inhibitors are associated with numerous drug interactions due to inhibition of the CYP3A4 isoenzyme. Pharmaceutical agents used to treat comorbidities in HIV-infected individuals often can interact with protease inhibitors, leading to toxic drug concentrations or untoward effects. Inhaled corticosteroids such as fluticasone propionate are often necessary to treat asthma in young children and are metabolized by CYP3A4. Interactions between protease inhibitors and inhaled fluticasone propionate have been reported in the adult population, but reports are limited in the pediatric literature.

Conclusions:

This case raises awareness of the interaction between fluticasone propionate and lopinavir/ritonavir and adverse effects in children receiving both medications.
Modeling and Predicting Mental Workload in En Route Air Traffic Control: Critical Review and Broader Implications
Authors: Loft Shayne , Sanderson Penelope , Neal Andrew , Mooij Martijn
Published: May 2007

Objective: We perform a critical review of research on mental workload in en route air traffic control (ATC). We present a model of operator strategic behavior and workload management through which workload can be predicted within ATC and other complex work systems. Background: Air traffic volume is increasing worldwide. If air traffic management organizations are to meet future demand safely, better models of controller workload are needed. Method: We present the theoretical model and then review investigations of how effectively traffic factors, airspace factors, and operational constraints predict controller workload. Results: Although task demand has a strong relationship with workload, evidence suggests that the relationship depends on the capacity of the controllers to select priorities, manage their cognitive resources, and regulate their own performance. We review research on strategies employed by controllers to minimize the control activity and information-processing requirements of control tasks. Conclusion: Controller workload will not be effectively modeled until controllers' strategies for regulating the cognitive impact of task demand have been modeled. Application: Actual and potential applications of our conclusions include a reorientation of workload modeling in complex work systems to capture the dynamic and adaptive nature of the operator's work. Models based around workload regulation may be more useful in helping management organizations adapt to future control regimens in complex work systems.
Automation Usage Decisions: Controlling Intent and Appraisal Errors in a Target Detection Task
Authors: Beck Hall P. , Dzindolet Mary T. , Pierce Linda G.
Published: May 2007

Background: It was proposed that misuse and disuse often occur because operators (a) cannot determine if automation or a nonautomated alternative maximizes the likelihood of task success (appraisal errors) or (b) know the utilities of the options but disregard this information when deciding to use automation (intent errors). Objective: This investigation assessed the effectiveness of performance feedback, a procedure developed to attenuate appraisal errors, and scenario training, an intervention designed to decrease intent errors. Methods: Operators given feedback were told how many errors they and an automated device made on a target detection task. Scenario training took operators through the thought processes of optimal decision makers after the utilities of the automated and nonautomated alternatives had been determined. Following 200 training trials, participants chose between relying on their observations or an automated device. Results: There was little misuse, but disuse rates were high (84%) among operators receiving neither feedback nor scenario training. Operators paired with a more accurate machine and given feedback made approximately twice as many errors as the automated device. Nevertheless, intent errors were commonplace; 55% of the operators who received feedback without scenario training did not rely on automation. Feedback effectiveness was enhanced when used in conjunction with scenario training; the disuse rate decreased to 29%. Conclusion: A combination of feedback and scenario training was more effective in mitigating disuse than either intervention used in isolation. Application: An important application of these findings is that operator training programs should incorporate techniques to control intent and appraisal errors.
Icon Identification in Context: The Changing Role of Icon Characteristics With User Experience
Authors: Isherwood Sarah J. , McDougall Siné J. P. , Curry Martin B.
Published: May 2007

Objective: This research examined the relative importance of icon characteristics in determining the speed and accuracy of icon identification. Background: Studies to date have focused on the role of one or two icon characteristics when users first experience an icon set. This means that little is known about the relative importance of icon characteristics or how the role of icon characteristics might change as users gain experience with icons. Methods: Thirty participants carried out an icon identification task over a long series of trials to simulate learning through experience. Icon characteristics investigated included semantic distance, concreteness, familiarity, and visual complexity. Results: Icon characteristics were major determinants of performance, accounting for up to 69% of the variance observed in performance. However, the importance of icon characteristics changed with experience: Semantic distance is crucial initially while icon-function relationships are learned, but familiarity is important later because it has lasting effects on access to long-term memory representations. Conclusion: These findings suggest that icon concreteness may not be of primary importance when identifying icons and that semantic distance and familiarity may be more important. Application: Designers need to take into account icon characteristics other than concreteness when creating icons, particularly semantic distance and familiarity. The precise importance of the latter characteristics will vary depending on whether icons are rarely encountered or frequently used.
Development and Evaluation of a Just-in-Time Support System
Authors: Drews Frank A. , Picciano Paul , Agutter James , Syroid Noah , Westenskow Dwayne R. , Strayer David L.
Published: May 2007

Objective: To lay the foundation for a framework of just-in-time support (JITS) for novices dealing with urgent, unfamiliar tasks, and to evaluate a JITS system. Background: More than 350,000 people die annually of cardiac arrest in the United States. In response, automated defibrillators are advocated that, unfortunately, do not provide important respiratory support. This paper presents elements of a framework for a JITS system that instructs a lay responder to follow a treatment protocol for integrating respiratory support with the use of an automatic external defibrillator. Method: We simulated a medical emergency using a high-fidelity patient simulator and asked participants to care for the patient. Results: When using a paper-based NASA treatment protocol, participants made more errors and took longer to stabilize the injured person than when using the JITS system. Conclusion: These findings demonstrate the benefit of a JITS system to instruct novices in unfamiliar tasks. Application: The JITS system has the potential to improve the treatment outcome of victims of cardiac arrest. The JITS framework can be applied to many situations in which novices deal with urgent tasks without expertise available.
Blood Vessels Form a Scaffold for Neuroblast Migration in the Adult Olfactory Bulb
Authors: Bovetti Serena , Hsieh Yi-Chun , Bovolin Patrizia , Perroteau Isabelle , Kazunori Toida , Puche Adam C.
Published: May 2007

New cells are continuously added to the rodent olfactory bulb (OB), throughout development and in adults. These cells migrate tangentially from the subventricular zone along the rostral migratory stream to the OB, where they migrate radically from the center to periphery of the OB. Although different modalities of radial migration have been described in other brain regions, the mechanisms governing radial migration in the OB are still mostly unknown. Here, we identify a new modality of migration in which neuronal precursors migrate along blood vessels toward their destination. Our results show that half of the radially migrating cells associate with the vasculature in the granule cell layer of the OB, andin vivotime-lapse imaging demonstrates that they use blood vessels as a scaffold for their migration through an interaction with the extracellular matrix and perivascular astrocyte end feet. The present data provide evidence that a new modality of migration, vasophilic migration, is occurring in the adult brain and reveals a novel role of brain vasculature.
Hedgehog Signaling in the Subventricular Zone Is Required for Both the Maintenance of Stem Cells and the Migration of Newborn Neurons
Authors: Balordi Francesca , Fishell Gord
Published: May 2007

We examined the postnatal consequences of removing Hedgehog signaling within the adult stem cell niche. Although at birth the subventricular zone appears normal in mice lacking Hedgehog signaling, by postnatal day 8 it is greatly impaired, and cell death is increased. In addition, both the quiescent B stem cell population and transit-amplifying C cells become depleted postnatally. In contrast, the A cell population expands precociously, mostly fails to migrate to the olfactory bulbs, and is ultimately also depleted by postnatal day 30.In vitroandin vivoanalyses demonstrate that this failure in migration is a result of nonautonomous signaling, possibly caused by a reduction in Slit1 ligand in A cells. These results suggest that Hedgehog signaling is required for the maintenance of the B and C cell populations and indirectly for the migration of the neurons that are generated from the adult stem cell niche.
Vollflächige Erfassung von ungestörten und gestörten Geschwindigkeitsverteilungen in Rohrleitungen mittels der Laser-Doppler-Velocimetrie (Completely Detection of Disturbed and Undisturbed Flow Conditions in Pipes with Laser Doppler Velocimetry)
Authors: Müller U. , Dues Michael , Baumann Henri
Published: May 2007

In dem Beitrag werden Geschwindigkeitsverteilungen über dem gesamten Querschnitt von durchströmten Rohrleitungen vorgestellt, die mittels der berührungslosen Laser-Doppler-Velocimetrie (LDV) gemessen wurden. Das weitgehend automatisierte Messregime basiert auf der Nutzung spezieller modularer Fensterkammern zur Gewährleistung der optischen Zugänglichkeit bei minimaler Beeinflussung der Strömung und einer dreidimensionalen Strahlverfolgungsrechnung mit Iteration. Es werden die Primär- und Sekundärströmungen quasi-ungestörter und gestörter Strömungszustände erfasst. Die Messungen erfolgen im Rahmen von Untersuchungen zum Nachweis und zur Optimierung der Strömungsverhältnisse von Kalibrier-Prüfständen für Durchfluss-Sensoren sowie der Verringerung der Empfindlichkeit dieser Messgeräte gegenüber Installationseffekten.
Making Moonshine: Thick Histories in a U.S. Historically Black Community
Authors: Brand Mieka
Published: May 2007

SUMMARY
In 1999 Union, Virginia, was officially recognized as a “historically black community” by the National Register of Historic Places. A short history was written in connection with official recognition—a narrative that is “accurate” as far as the facts are concerned but which reflects very little of the histories that Union's African‐American residents narrate themselves or, indeed, how history is shared among them in the first place. This article focuses on one historical narrative—the Moonshine Story—that did not make it into the official history but which was shared with some frequency among Union residents. Ethnographic research demonstrates that the social space in which people share knowledge determines not only what information is exchanged but how. In formal interview settings Union residents offered narratives that echo the structure and form of Union's official history. In informal settings, however, residents produced “thick” histories—three‐dimensional and dynamic narratives that are continually produced, that are patently conscious of their relationship to the present, and that affirm a shared sense of community among the speakers.
Sweet Water and Exotic Fish: Ethnographic Reflections of Environmental Imaginations in Ecuador and the Great Lakes
Authors: Syring David
Published: May 2007

SUMMARYThis article explores environmental imaginations in two cultural contexts—in the tales of an indigenous Saraguro, Ecuador, storyteller and in environmental science stories from the Great Lakes. By juxtaposing two examples of cultures grappling with the presence of exotic species in their waters, I raise comparative questions about how we conceptualize human‐environment relations in the contemporary world, as well as how moral authority regarding the environment is perceived in different cultural contexts. In bringing these two types of stories together, the article refutes the idea that scientifically based understandings of human‐environment relations are immune to culture.
Grassroots Prophecy in the Family International
Authors: Shepherd Gary , Shepherd Gordon
Published: May 2007

This paper describes the way in which ordinary members of The Family International have created a unique "culture of prophecy" in their communal homes that results in routine, daily "channeling" of spiritual messages for both individual and group guidance. Data were collected through field observations, survey questionnaires, and direct interviews in twenty-two different homes in sixteen different countries. Variations in individual prophetic ability and practice are shown to be correlated with variations in language skills, gender, leadership experience, and age of home members. In general, the member category most likely to rate higher on prophetic ability can be described as younger Family leaders, regardless of gender, who possess good language skills. These results reflect The Family's successful socialization and home schooling practices, as well as effective implementation of policies that empower females and young people. Specific steps in the formulation of home or team prophecies are also identified and described and the social implications of "democratizing" prophecy are discussed.
Lives Unled in Realist Fiction
Authors: Miller Andrew
Published: May 2007

Referring to fiction by Charles Dickens and Henry James, this essay considers the moral psychology of counterfactual narratives, studying pressures that invite the imagination of alternate lives. Such "optative" narratives, characteristic of realism, typically become important within particular environments of attention; glancing at economic and ideological factors, the argument focuses on marriage and the loss of children.
Telling to Live the Tale: Ronald Reagan, Edmund Morris, and Postmodern Nationalism
Authors: Maslan Mark
Published: May 2007

This essay treats the misrepresentation of personal history, by both author and subject, in Edmund Morris's controversial biography, Dutch: A Memoir of Ronald Reagan (1999) as the expression of a distinctly postmodern form of nationalism. In this version, which also informs current scholarship on the subject, historical deracination serves not simply as an obstacle to national connection but also as a basis for it. The essay closes with a critique of this paradoxical view.
Influence of 8‐bit vs. 11‐bit digital displays on observer performance and visual search: A multi‐center evaluation
Authors: Krupinski Elizabeth A. , Siddiqui Khan , Siegel Eliot , Shrestha Rasu , Grant Edward , Roehrig Hans , Fan Jiahua
Published: May 2007

Abstract— Medical‐grade monochrome monitors typically display 8 bits of data. This study determined if 11‐bit displays could improve observer performance and decrease use of window/level. 8‐ and 11‐bit displays from three manufacturers were used at three sites. Six radiologists at each site viewed 100 DR chest images (half with a pulmonary nodule) on both displays. Decisions, confidence, nodule location, viewing time, and window/level use were recorded. There was no significant difference in ROC Az as a function of bit depth. The average Az with 8 bits was 0.8284 and with 11 bits was 0.8253. There was a significant difference in viewing time favoring the 11‐bit displays. Window/level use did not differ. Eye position was recorded on a subset of images at one site. Cumulative dwell times for each decision category were lower with the 11‐bit than with the 8‐bit display. When tested with t‐tests for paired observations, the TP (t = 1.452, p = 0.1507), FN (t = 0.050, p = 0.9609), and FP (t = 0.042, p = 0.9676) were not statistically significant. The difference in the TN decisions was statistically significant (t = 1.926, p = 0.05). 8‐bit displays will not impact negatively diagnostic accuracy, but using 11‐bit displays may improve workflow efficiency.
What Is the Color of the Gonorrhea Ribbon?
Authors: Gilman Sander L.
Published: May 2007

Sexual politics in twenty-first century America has taken a rather surprising turn. Given the realities of the stigma still strongly associated with sexually transmitted diseases, the politics of HIV/AIDS is an unusual case study of acceptance in an age of sexual conservatism. This acceptance is contrasted through a close reading of a “young readers” novel about STDs with the ongoing stigma associated with other STDs. The politics of “abstinence only” becomes part of a discourse of the politics of human sexuality. In contrast the literature on herpes and ethnicity can be shown to engage with the problematics of identity politics missing from the STD texts. How the cultural and the medical literature parallel and differentiate themselves is a central aspect of this contrast.
Power to the People?
Authors: Craig Geofrey
Published: May 2007

This article explores the increasing politicization of “lifestyles” and outlines an understanding of the concept of “lifestyle politics.” This is conducted through a case-study discussion of protest actions against the upgrading of the electricity grid on the north island of New Zealand. The article also evaluates the exercise of the lifestyle politics of the protesters through a discussion of their use of the public communication process regarding the grid upgrade proposal and their mobilization of public opinion. Lifestyle politics is located in the contexts of theories of “life politics” (Giddens 1991) and “individualization” (Beck and Beck-Gernsheim 2002). The article argues that the concept of lifestyle extends beyond the pursuit of leisure and consumption practices and that lifestyle politics involves the expression of individual rights, the management of risk in everyday life, and a consciousness about the social responsibilities associated with a given lifestyle.
Rethinking Domination and Resistance: Challenging Postmodernism
Authors: Schutz Aaron
Published: May 2007

The emergence of postmodern ideas in the educational literature has complicated the field’s understandings of oppression and resistance. While important, this postmodern influence has been problematic in its tendency to stress the relatively nurturing forms of “pastoral” control generally experienced by the privileged. Such a focus can direct attention away from the often brutal discipline experienced by those who are more marginalized. The article examines contexts where pastoral or disciplinary forms of control predominate, noting the limited forms of resistance (if any) generated by each. It then looks to more sophisticated visions of resistance developed by scholars and activists. The article concludes by exploring the limitations inherent in any single approach to understanding or resisting domination.
State of the art in rockfall – forest interactions
Authors: Dorren Luuk , Berger Frédéric , Jonsson Martin , Krautblatter Michael , Mölk Michael , Stoffel Markus , Wehrli André
Published: May 2007

To effectively prevent rockfall related disasters below forested slopes, silvicultural, eco-engineering, civil engineering or mixed techniques can be used. To do this in a cost-efficient manner it is necessary to know the following:1) where rockfall events occur and which magnitudes are likely, 2) to what extent the forest reduces the run-out distances, the jump heights and the energies of rocks falling downslope, and 3) how the protective function of forests could be improved. This paper gives an overview of the current scientific knowledge and methods that are applied by practitioners who deal with rockfall and forests protecting against it. Efficient ways to derive information on the probable magnitude and frequency of future rockfall events from the source and deposit area are described. Subsequently, the scientific knowledge on the energy absorption capacity of single trees and the currently available knowledge on the protective function of forest stands against rockfall are presented. Then easy-to-use tools and simulation models for rockfall hazard assessment on forested slopes are described. Finally, this paper identifies the most important challenges to be tackled in the field of integrated rockfall-forest research.
Experimental Autoimmune Encephalomyelitis in the Mouse
Authors: Miller Stephen D. , Karpus William J.
Published: May 2007

This unit details the materials and methods required for both active induction and adoptive transfer of experimental autoimmune encephalomyelitis (EAE) in the SJL mouse strain using intact proteins or peptides from the two major myelin proteins: proteolipid protein (PLP) and myelin basic protein (MBP). Detailed materials and methods required for the purification of both PLP and MBP are also described. Modifications of the specified protocols may be necessary for efficient induction of active or adoptive EAE in other mouse strains.
Preparation and characterization of PDLC films formed using a two‐step procedure
Authors: Hsiao Yu‐Che , Chen Zhi‐Teng , Shau Min‐Da , Tsai Pai‐Feng
Published: May 2007

A novel polymer‐dispersed liquid crystal composite film was prepared using liquid crystal and dual resins, namely, UV‐curable urethane diacrylate and thermo‐curable epoxy, with a fixed LC content of 50 wt%. A combination treatment of UV irradiation and heat was performed in sequential steps. At first, the urethane diacrylate resin was cross‐linked through UV irradiation and a pre‐UV‐cured film was formed. Then, the pre‐UV‐cured film was heat treated for curing the thermo‐curable epoxy resin. As the thermal polymerization continued, LC droplets were formed and became embedded within the polymer matrix. PDLC films obtained from the polymer matrix with refractive indices in a range from 1.511 to 1.523 (1.517 ± 0.006) have optimal electro‐optical properties. Films with a refractive index higher than 1.523 have high contrast ratio (CR), threshold voltage (Vth), and V90, whereas those with a low refractive index of 1.508 have low CR, Vth, and V90. In this study, we found that PDLC composite films with optimal compositions prepared by dual resins (UV/thermal) have good electro‐optical properties. © 2007 Wiley Periodicals, Inc. Adv Polym Techn 26:14–20, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20087
Ein Bandenabsorptionsspektrum des Wassers bei Wellenlängen von mehreren Dezimetern
Authors: Weichmann Richard
Published: May 2007

A. Die Debyesche Theorie über die hohe Dielektrizitätskonstante vieler Flüssigkeiten. – B. Die Dispersion und Absorption des Wassers für elektrische Wellen im Bereich von λ = 64 cm bis λ = 27 cm. I. Die Versuchsanordnungen: 1. Die Lecherschen Drähte und die Plattenbrücken; 2. Das Thermokreuz; 3. Das Galvanometer; 4. Die Erreger und ihre Bereiche; 5. Die Oszillatorenhalter und die Schwingungskreise. II. Die Messungen in Luft: 1. Die Brückenverkürzungen; 2. Die Aufnahme der Resonanzkurven; 3. Die Formeln zur Auswertung der Messungen in Luft; 4. Die Dekremente. III. Die Messungen in Wasser: 1. Die Methode; 2. Die Formeln zur Auswertung der Messungen in Wasser; 3. Der Brechungsexponent; 4. Der Absorptionsindex. IV. Stellung der Resultate zu denen von Rückert und Rukop. – C. Zusammenfassung der Resultate und Ausblick auf weitere Fragen.
Elektrisches und optisches Verhalten von Halbleitern. II Äußere lichtelektrische Wirkung an Halbleitern. (Mit 17 Figuren)
Authors: Fleischmann R.
Published: May 2007

An Sulfid und Halogeniden des Silbers, den Oxyden des Kupfers, sowie an Fuchsin und Cyanin wird die äußere lichtelektrische Wirkung untersucht. Es soll dabei ermittelt werden, ob die lichtelektrischen Eigenschaften je nach Art der Elektrizitätsleitung verschieden sind. Die Versuche ergaben übereinstimmendes Verhalten von Elektronen‐ und Ionenleitern.

Die Einzelergebnisse sind in der Zusammenfassung am Schluß aufgeführt.
Über den Einfluß der Temperatur und gelöster Elektrolyte auf das monochromatische Debye‐Scherrer‐Diagramm des Wassers
Authors: Meyer Hans Heinrich
Published: May 2007

I. Einleitung. ‐ II. Versuchsanordnung. ‐ III. Das Diagramm des Wassers von 20° C bei Benutzung von Röntgenstrahlungen verschiedener spektraler Zusammensetzung. ‐ IV. Der Einfluß der Temperatur und gelöster Substanzen auf das Diagramm des Wassers mit streng monochromatischer Röntgenstrahlung. a) Übersicht über die angefertigten Aufnahmen; b) Die photometrische Ausmessung der Diagramme; c) Korrektionen der gemessenen Ablenkungswinkel und Intensitäten; d) Ergebnisse. ‐ V. Zusammenfassung.
Radiometerdruck und Akkommodationskoeffizient
Authors: Knudsen Martin
Published: May 2007

In der vorliegenden Arbeit wurde eine Untersuchung über Radiometerkräfte angestellt und zwar unter der Bedingung, daß alle Größen, von denen die Radiometerkraft abhängig sein könnte, insbesondere die auftretenden Temperaturen, gemessen wurden. Die Bedeutung des Akkommodationskoeffizienten für den Radiometerdruck wird nachgewiesen, und aus den Messungen bei niedrigen Drucken ergibt sich, daß der Akkommodationskoeffizient für die innere Energie einer zweiatomigen Gasart im untersuchten Falle dem Akkommodationskoeffizienten für die translatorische Energie gleichgesetzt werden kann.
Schallabsorption in mehratomigen Gasen
Authors: Kneser H. O.
Published: May 2007

Die endliche Einstelldauer des thermischen Gleichgewichts bewirkt in mehratomigen Gasen nicht nur Dispersion, sondern auch Absorption des Schalles. Unter diesem Gesichtspunkt kann das gesamte experimentelle Material über Schallabsorption (z. T. quantitativ) gedeutet werden.
Über den Mechanismus der plastischen Deformation der Eiseneinkristalle
Authors: Akulov N. , Raewsky S.
Published: May 2007

Ein Eiseneinkristall wurde einem stetigen Zusammenpressen über die Elastizitätsgrenze in der Richtung [100] unterworfen und die Suspensionfiguren, die sich auf der Ebene (010) angesetzt hatten, wurden untersucht.

Es wurde ein Effekt der periodischen Änderung der Richtung der Bitterschen Linien1) (S‐Linien) festgestellt. Dieser Effekt spricht für periodisch abwechselnde Gleitungen längs der Ebenen (100), (010) und (001) bei ununterbrochen steigender Deformation.
Eine neue Transformationstheorie linearer kanonischer Gleichungen
Authors: Lanczos Cornel
Published: May 2007

Es wird eine spezielle Gruppe der Hamiltonschen kanonsischen Gleichungen untersucht, bei denen die Hamiltonsche Funktion als quadratische Form der Veränderlichen qk, pk erscheint. Alle selbstadjungierten linearen Differentialgleichungen oder Systeme solcher Gleichungen, sowie alle Störungsprobleme der Mechanik und Astronomie gehören unter diese Gruppe. In Analogie zur üblichen Hauptachsentransformation quadratischer Formen auf Grund orthogonaler Transformationen wird die „kanonische Hauptachsentransformation”︁ der Hamiltonschen Funktion auf Grund linearer kanonischer Transformationen entwickelt. Im Hauptachsensystem sind die kanonischen Gleichungen separiert und direkt integrierbar. Diese Methode gibt ein sehr brauchbares sukzessives Näherungsverfahren zur Integration sämtlicher für die mathematische Physik fundamentaler Differentialgleichungen.
Vorgänge beim Zusammenstoß von K+‐Ionen mit Gasteilchen anorganischer und organischer Natur II. Mechanismus des Stoßprozesses
Authors: Schmidt Otto
Published: May 2007

Es wird gezeigt, daß der in der vorstehenden Arbeit angegebene Unterschied in dem Verhalten der beiden Klassen von Gasen gegenüber langsamen K+‐Ionen, bei denen in der ersten Klasse unter den Versuchsbedingungen bis 200 Volt fast nur elastische, in der zweiten jedoch in mehr oder weniger großem Maße unelastische Stöße auftreten, auf die Länge der Verweilzeit beim Stoß zurückzuführen ist, die ihrerseits wieder eine Funktion der Weichheit bzw. Härte und der Trägheit des gestoßenen Gasteilchens darstellt.
Berechnung verschiedener physikalischer Konstanten von heterogenen Substanzen. II. Dielektrizitätskonstanten und Leitfähigkeiten von Vielkristallen der nichtregulären Systeme
Authors: Bruggeman D. A. G.
Published: May 2007

Die Theorie von DK. und Lfk. der Mischkörper aus isotropen (amorphen oder regulären) Substanzen5) wird hier ausgedehnt auf die nichtregulären Systeme, wo schon der Vielkristall einer einzigen reinen Substanz den Charakter eines Mischkörpers aufweist. Die Genauigkeit der alten Formeln von Voigt und Andrade‐Chalmers wird untersucht, sodann werden neue Formeln abgeleitet für Vielkristalle und Mischkörper verschiedener Strukturen und diese am vorhandenen empirischen Material geprüft. Diese Prüfung ergibt eine gute Bestätigung der neuen Theorie, wobei wiederum einzelne Widersprüche zwischen den vorliegenden Messungen aufgehoben werden.
Über das dielektrische Verhalten des festen HBr in dem Umwandlungsintervall um 89° abs
Authors: Damköhler Gerhard
Published: May 2007

Es wurde das dielektrische Verhalten des festen HBr zwischen den Temperaturen 81 und 95° abs. untersucht. Dazu wurden Erwärmungs‐ und Abkühlungskurven aufgenommen, die sich einerseits über das gesamte genannte Temperaturgebiet erstrecken, andererseits nur über Teile desselben. Es ergaben sich für die Dielektrizitätskonstante Hysteresisschleifen (große und kleine), deren genaue Gestalt aus der Arbeit selbst zu ersehen ist. Es wurde ferner auf den einzelnen Ästen der Hysteresisschleifen die Temperatur längere Zeit (bis zu 11 Std.) auf 0,001° konstant gehalten und dabei beobachtet, daß gewisse Äste der Hysteresisschleifen sich tatsächlich zeitlich verändern und einem Grenzzustande zustreben, doch immer so, daß die Hysteresisschleifen dabei nicht verschwinden. Aus den Messungen geht hervor, daß die Hysteresis zum mindesten durch zwei Hemmungsarten bedingt ist, wovon die eine kinetischer Natur ist und in etwa 10 Std. ganz oder fast ganz verschwindet, während die andere Hemmung, wenn sie ebenfalls kinetisch wäre, erst nach wesentlich längeren Zeiten zurückgehen würde, die allerdings nicht abgewartet wurden. Vielleicht aber geht diese Hemmung überhaupt nicht zurück, so daß sie als thermodynamisch bedingt anzusehen wäre. Es wird vermutet, daß es sich bei der untersuchten HBr‐Umwandlung zwar um eine Rotationsumwandlung handelt, daß aber doch noch ein anderer Effekt für das Auftreten der Hysteresis verantwortlich ist: vielleicht ist es der Umstand, daß man im Gegensatz zu Flüssigkeiten und Gasen beim Kristallgitter grundsätzlich zwischen zwei Rotationsmöglichkeiten der Moleküle unterscheiden muß, zwischen der geordneten Rotation und der ungeordneten.
Über die quantenmechanische Umdeutung der Silbersteinschen Theorie
Authors: Neugebauer Th.
Published: May 2007

Die zur theoretischen Berechnung der Hauptpolarisierbarkeiten der Moleküle bekannten zwei Methoden, die klassische von Silberstein und die aus der quantenmechanischen Störungstheorie hergeleitete Methode werden miteinander verglichen. Das von mehreren Autoren gefundene Paradoxon, wonach die nach der Quantenmechanik berechneten Hauptpolarisierbarkeiten nicht einmal qualitativ mit den aus der Silberstein schen Theorie erhaltenen übereinstimmen, rührt davon her, daß die genannten zwei Methoden nicht zwei verschiedene Verfahren zur Berechnung derselben Erscheinung sind, sondern beide zwei verschiedene Wechselwirkungen der Atome darstellen und darum erst deren Summe mit der Erfahrung verglichen werden kann. Analoge Verhältnisse in der Theorie der kristallinen Doppelbrechung sind schon längst bekannt, der Silbersteinschen Theorie entspricht dort die Anisotropie der Lorentz‐Lorenzschen Kraft, der quantenmechanischen dagegen die von der Ladung der Nachbarionen und Überdeckung der Ladungswolken verursachte Beeinflussung der Eigenfunktionen. Zuletzt werden noch einige Bemerkungen zur Berechnung der Polarisationsenergie im inhomogenen Felde gemacht.
Zur Streuung und Dissoziation langsam bewegter Ionen
Authors: Wolf Franz
Published: May 2007

Mitteilung neuer Wirkungsquerschnittsmessungen. Überblick über das gesamte Versuchsmaterial von Wirkungs‐ und Umladungsquerschnitten. Abschätzung von Anregung, Ionisation und Streuung. Schlüsse über die Dissoziation.
Bemerkungen zur Kosmologie
Authors: Jordan P.
Published: May 2007

Es wird versucht, in groben Zügen diejenige kosmologische Theorie folgerichtig zu entwickeln, die sich ergibt, wenn man das „Diracsche Prinzip”︁ einerseits und die Geschlossenheit der (expandierenden) Welt andererseits als Grundlagen annimmt. Es ergibt sich (unter Wahrung des Energieprinzips) eine ständige Zunahme der Materie durch explosionsartige Erzeugungen von Sternen und Spiralnebeln.
Über die elektrische Leitfähigkeit von Zinkoxyd
Authors: Mollwo E. , Stöckmann F.
Published: May 2007

Diese Arbeit ist die erste von dreien, in denen mit der systematischen Untersuchung eines rein elektronischen Halbleiters begonnen wird. Diese weisen gewisse Vorteile bei der quantitativen Behandlung der Erscheinungen gegenüber den Alkalihalogeniden auf, die bis jetzt bevorzugt im hiesigen Institut untersucht wurden.—In der vorliegenden Arbeit beschreiben wir die Zusammenhänge zwischen lichtelektrischer Leitung, Dunkelleitung und optischer Absorption an zusammengesinterten ZnO‐Schichten.
Eine neue wellenmechanische Störungstheorie
Authors: Kallmann Hartmut , Päsler Max
Published: May 2007

Im folgenden wird ein neues Verfahren der Störungsrechnung für Probleme, die auf Differentialgleichungen 2. Ordnung führen, mitgeteilt. Es wird zunächst die ungestörte Differentialgleichung mittels Laplace‐Transformation in eine Differentialgleichung 1. Ordnung überführt — nur auf Probleme, bei denen dies möglich ist, läßt sich unser Verfahren mit Erfolg anwenden. — Bei der 𝔏‐Transformation der Störungsfunktion läßt sich diese häufig in die Form \documentclass{article}\pagestyle{empty}\begin{document}$\Sigma a_n \frac{{d^n g(p)}}{{dpn}}$\end{document} bringen. Dadurch wird die Differentialgleichung 1. Ordnung für g (p) zu einer solchen höherer Ordnung. Da die Differentialquotienten höherer Ordnung nur im Störungsglied stehen, lassen sie sich durch sukzessive Approximation direkt durch g (p) ausdrücken. Es entsteht dann eine Entwicklung nach Potenzen des Störparameters. Als Anwendung wird der Stark‐Effekt behandelt, und es wird gezeigt, daß sich allein durch einfache Quadraturen seine Eigenwerte und Eigenfunktionen ermitteln lassen. Die so gefundenen Ergebnisse stehen in vollkommener Übereinstimmung mit denen, die die bisher gebräuchlichen Störungsmethoden lieferten.
Durch Hochfrequenzimpulse angeregte mechanische Schwingungen von Quecksilberkapillaren. (Mit 6 Abbildungen)
Authors: Laporte Hansgeorg
Published: May 2007

Es wird gezeigt, wie durch einen elektromagnetischen Schwingungsimpuls ein Quecksilberfaden in einer Kapillare zu mechanischen Schwingungen angeregt werden kann. Die Schwingungen wurden mit Zeitlupenaufnahmen und Funkenphotographien fixiert. Sie werden hauptsächlich durch elektrodynamische Stromwirkung mit Verzögerung angeregt. Die thermische Stromwirkung ist gering und abhängig von der Dauer des elektrischen Impulses.
Untersuchungen über die Bewegung des Brennflecks auf der Kathode eines Quecksilberdampf‐Niederdruckbogens. (Mit 24 Abbildungen)
Authors: Schmidt Erwin
Published: May 2007

Mit Hilfe von Zeitlupenaufnahmen eines Hg‐Niederdruckbogens wird bei höheren Stromstärken eine Aufteilung der kathodischen Entladung in einzelne Brennflecke gefunden. Dabei beträgt die statistisch schwankende Stromstärke eines einzelnen Flecks im Mittel etwa 6,7 A. (Kap. II a.)

Die Unruhebewegung eines einzelnen Flecks entspricht rein formal der Brownschen Bewegung eines kleinen Teilchens in einem ebenen Gas. Das für die Molekularbewegung gültige Gesetz, daß das mittlere Verschiebungsquadrat des Teilchens der Beobachtungszeit proportional sein muß, läßt sich auch auf die zufällige Brennfleckwanderung anwenden. Da das Verschiebungsgesetz auch noch bei den kleinen Beobachtungszeitintervallen von 4 · 10−4 s die Verhältnisse richtig wiedergibt, muß man annehmen, daß der zeitliche Abstand der den Brennfleck ungeordnet umlenkenden Vorgänge um mindestens eine Zehnerpotenz geringer ist als diese kürzeste Beobachtungszeit. (Kap. II b.)

Auf den Brennfleck wird ferner bei geeigneter Form der Entladungsstrecke eine Richtkraft ausgeübt, die ihn in eine der Verkürzung der Bogensäule entsprechende Richtung treibt. (Kap. II c.)

Es wird vermutet, daß diese Richtkraft mit dem Steenbeckschen Minimumprinzip ursächlich zusammenhängt und daß sich die Häufigkeitsverteilung des Brennflecks über den Kathodenquerschnitt durch einen Boltzmann‐Ansatz beschreiben läßt, dessen Exponent durch das Verhältnis einer mit der Brennspannung monoton steigenden Funktion zur thermischen Unordnungsenergie gegeben ist. (Kap. III a.)

Statistische Messungen der Häufigkeitsverteilung auf einer ebenen Kathode im Zusammenhang mit der Brennspannungsverteilung ergeben, daß diese Annahme (Abs. 4) nicht zu Recht besteht. (Kap. III b c).

Der an einer linearen (in einer Richtung stark ausgedehnten) Kathode gemessene Zusammenhang zwischen der örtlichen Häufigkeitsverteilung des Brennfleks und den zugehörigen Brennspannungswerten läßt sich sehr genau durch einen Boltzmann‐Ansatz wiedergeben. (Kap. III d e.)

Die zwischen den Exponenten des Boltzmann‐Ansatzes, der Diffusionskonstanten des Brennflecks und seiner Driftgeschwindigkeit nach der Theorie der statistischen Schwankungserscheinungen bestehenden Zusammenhänge erweisen sich für den Fall der linearen Kathode als befriedigend erfüllt. (Kap. IV.)

Ohne Zuhilfenahme weiterer Annahmen ist eine Deutung der bisherigen Meßergebnisse durch des Minimumprinzip nicht möglich. ( Kap. V.)

Durch Untersuchung des Einflusses von transversalen Magnetfeldern aud die Driftgeschwindigkeit des Brennflecks wird auf den Feldeinfluß des Entladungsstromes geschlossen. Berücksichtigt man einen von J.Stark gefundenen Effekt , bei dem der Brennfleck vom transversalen Magnetfeld im elektrodynamisch falschen Sinne abgelenkt wird, so lassen sich die Meßergebnisse allein durch die Wirkung des magnetischen Eigenfeldes der Entladung deuten. (Kap. VI.)