bluuebunny/crossref_metadata_2025 huggingface dataset:
The Value of Routine Real Ear Measurement of the Gain of Digital Hearing Aids
Authors: Aazh Hashir , Moore Brian C.J.
Published: April 2008

The main aims of this study were: (1) to determine whether routine real ear insertion gain (REIG) measurement is necessary in fitting digital hearing aids; and (2) to assess the extent to which modifying the frequency-gain response of an aid can lead to better matches to the target
in cases where the target gain was not initially achieved. The target formula was selected as NAL-NL1 in the programming software of four types of digital hearing aids. REIG measurements on 42 ears showed that 64% of cases failed to come within ±10 dB of the target at one or more of
the following frequencies: 0.25, 0.5, 0.75, 1, 1.5, 2, and 4 kHz. After adjusting the frequency-gain response of the aids, based on the REIG results, 83% of cases came within ±10 dB of the target. The target was met more often, both before and after adjustment, for aids with seven gain
“handles” than for aids with four gain “handles.” The results indicate that REIG measurements can and should be used to achieve more accurate fittings but that accurate adjustments are difficult with some aids. Los propósitos principales de este estudio fueron:
(1) determinar si las mediciones rutinarias de ganancia de inserción en oído real (REIG) son necesarias para adaptar auxiliares auditivos digitales; y (2) evaluar el grado en que la modificación de la respuesta de ganancia por frecuencia de un auxiliar puede llevar a mejores
ajustes en los casos donde la ganancia meta no le logró inicialmente. La fórmula meta fue seleccionada como la NAL-NL1 en el software de programación de cuatro tipo de auxiliares auditivos digitales. Las mediciones del REIG en 42 oídos mostró que el 64% de
los casos fallaron en acercarse a ± 10 dB de la meta, en una o más de las siguientes frecuencias: 0.25, 0.5, 0.75, 1, 1.5, 2, y 4 kHz. Luego de ajustar la respuesta de ganancia por frecuencia, con base en los resultados del REIG, 83% de los casos se acercaron a ± 10 dB
de la meta. La meta fue alcanzada más a menudo, tanto antes y después del ajuste, para auxiliares con siete ajustes de ganancia que para auxiliares con cuatro ajustes. Los resultados indican que las mediciones de REIG pueden y deberían ser utilizadas para lograr adaptaciones
más exactas, pero que tales ajustes exactos son difíciles en algunos auxiliares.
A Meta-analytic Comparison of Binaural Benefits between Bilateral Cochlear Implants and Bimodal Stimulation
Authors: Schafer Erin C. , Amlani Amyn M. , Seibold Andi , Shattuck Pamela L.
Published: April 2008

A meta-analytic approach was used to examine sixteen peer-reviewed publications related to speech-recognition performance in noise at fixed signal-to-noise ratios for participants who use bilateral cochlear implants (CIs) or bimodal stimulation. Two hundred eighty-seven analyses were
conducted to compare the underlying contributions of binaural summation, binaural squelch, and the head-shadow effect compared to monaural conditions (CI or hearing aid). The analyses revealed an overall significant effect for binaural summation, binaural squelch, and head shadow for the bilateral
and bimodal listeners relative to monaural conditions. In addition, all within-condition (bilateral or bimodal) comparisons were significant for the three binaural effects, with the exception of the bimodal condition compared to a monaural CI. No significant differences were detected between
the bilateral and bimodal listeners for any of the binaural phenomena. Clinical implications and recommendations are discussed as they relate to empirical findings. Se utilizó un enfoque de meta-análisis para examinar dieciséis publicaciones con revisión editorial
relacionadas con el desempeño en reconocimiento del lenguaje en medio de ruido a tasas de señal-ruido fijas, para participantes que usaban implantes cocleares bilaterales (IC) o estimulación bimodal. Se condujeron doscientos ochenta y siete análisis para comparar
la contribución subyacente de la sumación bi-auricular, el chapoteo bi-auricular, y el efecto de sombra de la cabeza, en comparación con las condiciones mono-auriculares (IC y auxiliar auditivo). El análisis reveló un efecto global significativo para la sumación
bi-auricular, el chapoteo bi-auricular y la sombra de la cabeza para el sujeto con audición bilateral y bimodal, en relación con las condiciones monoauriculares. Además, todas las comparaciones dentro de la misma condición (bilateral o bimodal) fueron significativas
para los tres efectos bi-auriculares, con la excepción de la condición bimodal, comparada con un IC monoauricular. No se detectaron diferencias significativas entre sujetos en condición bilateral y bimodal para ninguno de los fenómenos bi-auriculares. Las implicaciones
clínicas y las recomendaciones se discuten en tanto se relacionan con los hallazgos empíricos.
The Impact of Listening with Directional Microphone Technology on Self-Perceived Localization Disabilities and Handicaps
Authors: Ruscetta Melissa N. , Palmer Catherine V. , Durrant John D. , Grayhack Judith , Ryan Carey
Published: April 2008

The chief complaint of individuals with hearing impairment is difficulty hearing in noise, with directional microphones emerging as the most capable remediation. Our purpose was to determine the impact of directional microphones on localization disability and concurrent handicap. Fifty-seven
individuals participated unaided and then in groups of 19, using omni-directional microphones, directional-microphones, or toggle-switch equipped amplification. The outcome measure was a localization disabilities and handicaps questionnaire. Comparisons between the unaided group versus the
aided groups, and the directional-microphone groups versus the other two aided groups revealed no significant differences. None of the microphone schemes either increased or decreased self-perceived localization disability or handicap. Objective measures of localization ability are warranted
and if significance is noted, clinicians should caution patients when moving in their environment. If no significant objective differences exist, in light of the subjective findings in this investigation concern over decreases in quality of life and safety with directional microphones need
not be considered. La principal queja de los individuos con trastornos auditivos es la dificultad para escuchar en medio de ruido, emergiendo los micrófonos direccionales como el más capaz remedio. Nuestro propósito fue determinar el impacto de los micrófonos direccionales
en la incapacidad de localización y en los impedimentos concurrentes. Cincuenta y siete individuos participaron sin amplificación y luego, en grupos de 19, utilizando micrófonos omni-direccionales, micrófonos direccionales, o amplificación equipada con interruptores
de palanca. La medida de resultado fue un cuestionario de discapacidades e impedimentos de localización. Las comparaciones entre el grupo sin amplificación versus los grupos con amplificación, y entre el grupo con micrófono direccional versus los otros dos grupos
con amplificación no revelaron diferencias significativas. Ninguno de los esquemas de micrófono aumentó o disminuyó la discapacidad o el impedimento auto-percibido de localización. Las medidas objetivas de la habilidad de localización se garantizan
y si se llega a notar algo significativo, los clínicos deberían advertir a los pacientes cuando se desplacen en sus ambientes. Si no existen diferencias objetivas significativas, a la luz de los hallazgos subjetivos de esta investigación, no debe considerarse ninguna preocupación
sobre la disminución de la calidad de vida o la seguridad con el uso de micrófonos direccionales.
END‐USER ORIENTED PUBLIC‐PRIVATE PARTNERSHIPS IN REAL ESTATE INDUSTRY
Authors: Majamaa Wisa , Junnila Seppo , Doloi Hemanta , Niemostö Emma
Published: April 2008

The European Union (EU) is reforming its public services and suggesting Public‐Private Partnerships (PPPs) as a solution for producing high quality and cost effective real estate service delivery. However, the use of PPP approach in real estate industries has been found to have significant constraints related to the end‐users’ (general public's) perspective. The purpose of the paper is to show how PPP projects have failed to produce desirable characteristics expressed in purchasing processes and fulfilment of the end‐user expectations. While the customer‐oriented development of public services and the needs of the end‐users were noted to be crucial points in all five major Finnish PPP projects studied, the case studies pointed out a fundamental lack of understanding and maintaining the end‐user perspective through the tendering and evaluation processes. Especially, in the final stage of evaluation, and evaluation criteria used to decision making, the disappearance of the end‐users’ perspective was evident. The findings are further used to develop a new suggested Public‐Private‐People Partnership (4P) model. The results can be useful to the public sector's purchasers and to the private sector's providers to understand the limitations of current PPP practices and to further develop their practices towards more customer‐oriented service production.

Santrauka

Europos Sąjunga (ES) vykdo viešųjų paslaugų reformą ir viešąsias bei privačiąsias partnerystes (VPP) siūlo kaip sprendimą teikti pigias ir kokybiškas nekilnojamojo turto paslaugas. Tačiau pastebėta, kad nekilnojamojo turto sektoriuose VPP požiūris susiduria su reikšmingais suvaržymais, kurie yra susiję su galutinių vartotojų (plačiosios visuomenės) perspektyva. Šiame darbe siekiama pademonstruoti, kaip VPP projektams nepavyko pasiekti pirkimo procesuose numatytų pageidaujamų charakteristikų ir patenkinti galutinio vartotojo lūkesčius. Nors visi penki pagrindiniai Suomijos VPP projektai, kurie yra nagrinėjami darbe, į klientą orientuotą viešųjų paslaugų plėtrą ir galutinių vartotojų poreikius nurodo kaip svarbiausius punktus, atvejo tyrimai parodė, kad gebėjimo suprasti bei išlaikyti galutinio vartotojo perspektyvą iš esmės trūko ir organizuojant konkursus, ir vertinant. Galutinio vartotojo perspektyvos išnykimas ypač akivaizdžiai išreiškia galutinis vertinimo etapas ir vertinimo kriterijai, kuriais grindžiami sprendimai. Išvados pritaikytos plėtojant naują siūlomą viešosios bei privačiosios žmonių partnerystės (VPŽP) modelį. Rezultatai naudos gali duoti viešojo sektoriaus pirkėjams ir privačiojo sektoriaus tiekėjams, siekiant suprasti esamų VPP praktikų ribotumą ir toliau plėtojant savo praktikas, kad teikiamos paslaugos būtų labiau orientuotos į klientą.
PROPERTY MARKET NATURE AND THE CHOICE OF PROPERTY PORTFOLIO DIVERSIFICATION STRATEGIES: THE NIGERIA EXPERIENCE
Authors: Olaleye Abel
Published: April 2008

With a focus on the Nigerian property market, this paper considered and empirically analyzed how property market nature and the perception of market players of some qualitative factors have impacted on choice of property portfolio diversification strategies. Questionnaires, backed up with interviews, were administered on 28 institutional property investors and 159 real estate practitioners in three commercial nerve centres of Nigeria, namely, Lagos, Abuja and Port‐Harcourt metropolitan areas. The frequency distribution analyses’ results revealed that the Nigerian property market was an emerging one and, as it is expected, there was dearth of time series data while investors in the market were small time institutional investors. Using mean rating on a 4‐point rating scale, the study found six factors, arising from the nature of the property market, as the significant factors impacting on choice of diversification strategies. These are: the investors’ overall expectation of the benefits of diversification scheme, the need to reduce management operating costs, management convenience, operating environment, market players’ education and knowledge of alternative diversification techniques and availability or otherwise of data in the market. The result of cross tabulation and Chi‐square test also indicated that there was a statistically significant relationship between educational qualifications of practitioners and their choice of diversification strategies. Santrauka Daugiausia dėmesio skiriant Nigerijos nuosavybės rinkai, šiame darbe apžvelgta ir empiriškai išanalizuota įtaka, kurią, renkantis nuosavybės portfelio diversifikacijos strategijas, daro nuosavybės rinkos prigimtis ir tai, kaip kai kurie rinkos dalyviai suvokia tam tikrus kokybinius veiksnius. Pasitelkus anketas ir pokalbius, apklaustos 28 į nuosavybę investuojančios organizacijos ir 159 nekilnojamojo turto specialistai trijuose pagrindiniuose Nigerijos komerciniuose centruose, t. y. Lagose, Abudžoje ir Port-Harkorte. Dažnių lentelių analizės rezultatai parodė, kad Nigerijos nuosavybės rinka yra kylanti ir, kaip tikimasi, trūko laiko eilučių duomenų, nes rinkoje veikiantys investuotojai buvo smulkūs instituciniai investuotojai. Apskaičiavus vertinimų vidurkį pagal keturių balų skalę, tyrimo metu nustatyti šeši veiksniai, susiję su nuosavybės rinkos prigimtimi, kurie daro reikšmingą įtaką renkantis diversifikacijos strategijas. Jie yra tokie: bendrieji investuotojų lūkesčiai dėl iš diversifikacijos schemos gaunamos naudos, poreikis mažinti operatyvines vadybos išlaidas, valdymo patogumas, operatyvinė aplinka, rinkos veikėjų išsilavinimas ir žinios apie alternatyvius diversifikacijos metodus bei prieinamos arba kitaip pasiekiamos žinios rinkoje. Be to, kryžminių lentelių ir Chi kvadrato kriterijaus rezultatai parodė, kad tarp specialistų išsilavinimo (kvalifikacijos) ir jų pasirinktų diversifikacijos strategijų yra statistiškai reikšmingas ryšys.
Helper‐Dependent Adenoviral Vectors
Authors: Oka Kazuhiro , Chan Lawrence
Published: April 2008

The helper‐dependent adenovirus (HDAd) is a recently developed adenovirus‐based vector with an improved safety profile and long‐term transgene expression. In this unit, a basic procedure for HDAd production using the Cre‐loxP system is presented. Amplification and large‐scale production of the vector can be done in both adherent and suspension cell culture systems. Included are protocols for Southern blot analysis to monitor vector amplification, slot blot assay to determine the infectious titer of the purified HDAd, and real‐time PCR to detect helper virus contamination in the preparation.
Mass transport enhancement in the DMFC using an externally applied oscillatory flow
Authors: Schonewill Philip P. , Leighton David T.
Published: April 2008

The direct methanol fuel cell experiences performance decay at high current densities due to mass transfer limitations. The dominant mass transfer limiting mechanism at high methanol/water feed rates and low methanol feed concentrations has been attributed to the slow diffusion of methanol through the porous diffusion layer of the anode. In this study, fluid oscillations were induced in the feed to the anode of a DMFC and significant performance improvements were observed at high current densities. It was found that the improvement in measured limiting current densities over steady flow operation was as large as twofold and the peak power density increased by as much as 30%. A model is presented which predicts the experimental values of limiting current density as a function of the Peclet number in the porous diffusion layer of the DMFC anode. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Gas permeation through DDR‐type zeolite membranes at high temperatures
Authors: Kanezashi Masakoto , O'Brien‐Abraham Jessica , Lin Y. S. , Suzuki Kenji
Published: April 2008

DDR‐type zeolite membranes were prepared by the secondary growth method on porous α‐alumina disk, followed by on‐stream counter diffusion chemical vapor deposition modification to eliminate the intercrystalline micropores. Single gas permeation of He, H2, CO2, and CO through this zeolite membrane before and after CVD modification was measured in 25–500°C. Intracrystalline diffusivities for these four gases in DDR‐type zeolite were obtained from the permeation data above 300°C to examine the effects of the size and molecular weight of permeating gases on diffusion and permeation rate for this zeolite membrane. For the unmodified DDR‐type zeolite membrane with presence of a small amount intercrystalline micropores the diffusivity (or permeance) with a low activation energy depends on both the size and molecular weight of permeating gases. For the CVD‐modified DDR‐type zeolite membrane with intercrystalline micropores eliminated, the activation energy for diffusion and diffusivity increases with increasing molecular size of the permeating gases. © 2008 American Institute of Chemical Engineers AIChE J, 2008.
Two Diammonium Copper Azides with Similar Layerlike Magnetic Substructures Made of Chains of Serially Connected Cu6 Rings Show Cation‐Modulated Magnetism
Authors: Liu Tao , Yang Yan‐Fei , Wang Zhe‐Ming , Gao Song
Published: April 2008

We present here the first examples of Cu–azide compounds synthesized by using protonated diamine ions as cationic templates: (dmenH2)[Cu6(N3)14] and (trimenH2)[Cu6(N3)14] (dmenH22+: N,N′‐dimethylethylenediammonium; trimenH22+: N,N,N′‐trimethylethylenediammonium). Both compounds possess a similar, rarely observed anionic Cu–azide layer, which consists of [Cu6(N3)142−]n anionic chains linked by asymmetric end‐to‐end azido bridges. The chain, in turn, is made up of elongated Cu6 rings, with double and single end‐on azido linkages between the square‐planar Cu2+ sites within the ring and double end‐on azido bridges serially connecting the rings. The molecular geometry results in ferromagnetic interactions within the Cu–azide layer in both compounds. The interlayer separations are determined by the cations, with the shortest interlayer Cu⋅⋅⋅Cu separations being 8.016 Å for the dmenH22+ compound and 9.106 Å for the trimenH22+ compound. These different interlayer separations tune the magnetic properties of the two materials. The dmenH22+ compound displays long‐range antiferromagnetic ordering at lowtemperature and short‐range ferromagnetic interaction at high temperature, while only short‐range ferromagnetism was observed in the trimenH22+compound at 2–300 K.
Effects of weak mobile Phone—Electromagnetic fields (GSM, UMTS) on well‐being and resting EEG
Authors: Kleinlogel H. , Dierks T. , Koenig T. , Lehmann H. , Minder A. , Berz R.
Published: April 2008

Modern mobile phones emit electromagnetic fields (EMFs) ranging from 900 to 2000 MHz which are suggested to have an influence on well‐being, attention and neurological parameters in mobile phone users. To date most studies have investigated Global System for Mobile Communications (GSM)‐EMF and only very few studies were concerned with Universal Mobile Telecommunications System (UMTS)‐EMF. Consequently, we tested the effects of both types of EMF, 1950 MHz UMTS (SAR 0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on well‐being and vigilance‐controlled resting electroencephalogram (eyes closed) in 15 healthy, right‐handed subjects. A double‐blind, randomised, crossover application of the test procedure was used. Neither the UMTS‐ nor the GSM‐EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users. Bioelectromagnetics 29:479–487, 2008. © 2008 Wiley‐Liss, Inc.
A sensitive and selective immuno‐nanogold resonance‐scattering spectral method for the determination of trace penicillin G
Authors: Jiang Zhiliang , Li Yan , Liang Aihui , Qin Aimiao
Published: April 2008

A sensitive and selective immuno‐nanogold resonance scattering spectral assay was developed for the determination of trace hapten penicillin G, based on the resonance scattering (RS) effect of the nanogold at 560 nm, and the nanogold‐labelled immunoreaction took place in pH 5.4 phosphate citric acid buffer solutions and in the presence of polythylene glycol (PEG). The nanogold‐labelled immunocomplex formed more and more with addition of penicillin G. The enhanced RS intensity at 560 nm ΔIRS was linear to the penicillin G concentration in the range 7.5–1700 ng/mL, with a detection limit of 0.78 ng/mL. The results indicate that the immunonanogold‐labelled RS spectral assay has a high specificity and sensitivity for quantitative determination of penicillin G in raw milk samples. Copyright © 2008 John Wiley & Sons, Ltd.
Nächtliches Farbensehen. Bei Nacht sind nicht alle Katzen grau
Authors: Kelber Almut
Published: April 2008

Während Menschen und die meisten anderen Wirbeltiere tagsüber mithilfe der Zapfen Farben sehen und nachts auf das farbenblinde Sehen mit Stäbchen angewiesen sind, haben einige Tiere selbst noch bei Sternenlicht die Fähigkeit, Farben zu unterscheiden. Insekten haben nicht wie wir Zapfen und Stäbchen, sondern sehen tags und nachts mit denselben Sehzellen. Nachtgeckos haben ebenfalls keine Stäbchen und können mithilfe ungewöhnlich empfindlicher Zapfen nachts Farben sehen. Nächtliches Farbensehen setzt extrem empfindliche Augen voraus: Nachtschwärmer haben Facettenaugen vom Superpositionstyp, Nachtgeckos haben große Pupillen und kurze Brennweite. Nächtliches Farbensehen ist vorteilhaft, weil sich das Licht in der Abenddämmerung und damit die Helligkeit verschiedenfarbiger Objekte stark ändert. Farbensehen erlaubt unter diesen Bedingungen, Objekte zuverlässig zu erkennen.
Erfolgsmodell Libelle. Fliegende Spinnennetze
Authors: Hilfert‐Rüppell Dagmar , Rüppell Georg
Published: April 2008

Die thermischen Anpassungen von Pech‐, Pracht‐ und Großlibellen werden vorgestellt. Pechlibellen sind äußerst erfolgreich und aggressiv. Sie fressen gleich große andere Libellen und selbst Artgenossen. Prachtlibellen fliegen mit den größten Beschleunigungen und sind äußerst wendig. Sie sind auf kleine Beute spezialisiert. Bei ihnen ist die Fortpflanzung durch ein Territorialsystem weitgehend geordnet. Einige Großlibellen schaffen es trotz ihres hochentwickelten Flugapparates ebenfalls, bei kühlen Temperaturen aktiv zu werden. So erlauben Studien an Libellen interessante Einblicke in die Mechanismen der Evolution.
Wie Ameisen ihre Lieblingspflanzen erkennen
Authors: Brennicke Axel
Published: April 2008

Im Regenwald des Amazonas legen Ameisen in Bäumen Gärten mit ganz bestimmten Epiphyten an, deren Samen sie auch ohne Fruchtfleisch identifizieren. Jetzt hat sich herausgestellt, dass die Samen Lockstoffe in die Luft abgeben, an denen die Ameisen sie erkennen.
Kurswechsel im Immunsystem
Authors: Hille‐Rehfeld Annette
Published: April 2008

Lebenswichtige Abwehrreaktionen des Immunsystems dürfen nicht überhandnehmen, sonst drohen chronische Entzündungen oder Autoimmunerkrankungen. Als Schalthebel für die Regulierung der Aktivität von Immunzellen wurde jetzt ein Rezeptor erkannt, der zu Beginn einer Abwehrreaktion entzündungsfördernde Reaktionen steuert, danach aber durch Interaktion mit einem antagonistischen Zelloberflächenrezeptor für die Begrenzung der Immunreaktion sorgt.
Wie nimmt man einen genetischen Fingerabdruck?
Authors: Leinweber Ina
Published: April 2008

Aus der Kriminaltechnik ist er nicht mehr wegzudenken: Der “genetische Fingerabdruck”. Aber nicht nur für die Aufklärung von Verbrechen ist ein DNA‐Profil wichtig, sondern auch, um die Herkunft von Fleisch, die Anfälligkeit für bestimmte Erbkrankheiten oder eine Vaterschaft zu bestimmen. Doch was wird dabei eigentlich genau gemacht?
Indien: Mangroven als Küstenschutz
Authors: Ravikumar S. , Kronberg Inge
Published: April 2008

Zwischen Land und Meer wachsen in den gemäßigten Klimazonen allenfalls salztolerante Kräuter und Gräser. In den Tropen hingegen formen hoch spezialisierte Bäume den Lebensraum Mangrove. Seit 1980 ist die Mangrovenfläche weltweit durch Umwandlung, Übernutzung und Verschmutzung um mindestens ein Viertel zurückgegangen. Dadurch gehen nicht nur Ressourcen verloren, auch der Küstenschutz und die Produktivität der umgebenden Küstengewässer sind beeinträchtigt.
Moderne Genetik erleben
Authors: Goebel Theresa , Nellen Wolfgang
Published: April 2008

Im Juli tagt zum ersten Mal seit 80 Jahren der Internationale Kongress für Genetik in Deutschland. Weit über tausend Genetiker aus aller Welt werden vom 12. bis 17. Juli 2008 in Berlin erwartet, um in mehreren hundert Fachvorträgen die aktuelle Forschung in allen Teilgebieten der Genetik zu diskutieren. Parallel hat die Gesellschaft für Genetik (GfG) als Organisator ein spannendes Programm für interessierte Laien ins Leben gerufen, um zur Diskussion über Chancen und Risiken gentechnischer Forschung anzuregen.
The Roll of Chemocatalysis in the Establishment of the Technology Platform “Renewable Resources”
Authors: Claus P. , Vogel H.
Published: April 2008

The FRG has no economical access to crude oil. It is therefore an important future task to organize a post‐fossil sustainable era of material economy and to develop new processes based on alternative carbon sources. The change in raw material base is not a new experience for the chemical industry, it has always generated a wave of innovation and an economic boom. A precondition for this is to early develop scientific and technological bases for the new, yet age‐old raw material base biomass and to use the existing know‐how of petrochemistry, especially in the area of chemocatalysis.
Catalytic Processes for the Technical Use of Natural Fats and Oils
Authors: Behr A. , Westfechtel A. , Pérez Gomes J.
Published: April 2008

Vegetable fats such as rapeseed oil, sunflower oil, palm oil or coconut oil consisting of triglycerides offer different carbon chain distributions. The use of these raw materials for the production of industrial chemicals as well as for fuel (biodiesel), which is finally a substitution for mineral oil, is a political discussion with various facets. The basic products such as fatty acids, fatty alcohols, and esters have different physical properties and lead to various areas of application depending on the carbon chain distribution. While the chain length range of C12 represents important raw materials for detergents, chain lengths of C18 are used mainly in industrial applications, e.g. as lubricants. Natural fatty alcohols are produced by the heterogeneous catalyzed high‐pressure hydrogenation of methyl esters or fatty acids. The unsaturated fats and oils can be derivatized catalytically by functionalization, oligomerization, oxidation or metathesis. Thereby, new functional groups are introduced into the oleochemical substrate. The carbon chain length can be increased or reduced respectively, or a branching in the fatty chain is introduced. Products with completely new properties and areas of applications are available due to these catalytic variations of fats and oils.
Vegetal Refining and Agrochemistry
Authors: Delmas M.
Published: April 2008

The industrial process developed by CIMV is a world first for the manufacture of whitened paper pulp, sulfur free linear lignin and xylose syrup from annual fiber crops and hardwood. This new technology allows the separation without degradation of the three main components, i.e., cellulose, hemicelluloses and lignins, isolated from the vegetable matter. The CIMV process is a biorefinery functioning on a model resembling an oil refinery. The lignins have a linear structure that permits high reactivity with different monomers producing new polymers and new formaldehyde‐free adhesive formulations. The C‐5 sugar syrup can be used to produce additives for animal feeding and chemicals. The pilot plant in operation since 2006, near Reims, has given fully satisfactory results. The CIMV chemical engineering approach, proceeds by the use of classical industrial equipment. This should allow the scale up of the original CIMV concept to result in production at industrial levels in 2009.
Raw Material Changes in the Chemical Industry
Authors: Diercks R. , Arndt J.‐D. , Freyer S. , Geier R. , Machhammer O. , Schwartze J. , Volland M.
Published: April 2008

Until the 19th century, renewable raw materials were the major source of energy generation and material use. With the Industrial Revolution, the use of coal increased sharply and coal quickly developed into a key raw material in the chemical industry, mainly in the production of dyes. In the past century, there has been a consistent changeover in fossil fuel sources from coal to crude oil and natural gas due to lower prices, simpler logistics and the versatility in usage of oil and gas. In view of the limited availability and increasing price of crude oil and natural gas, the question now arises as to how the raw material base will develop in the future?
Change in Raw Material Base in the Chemical Industry
Authors: Vogel G. H.
Published: April 2008

The change in raw material base is nothing new to the chemical industry, it has always generated a wave of innovation and an economic boom. A prerequisite for this is the early development of scientific and technological bases for a renewed raw material change. Even the chemical industry, being well acquainted with the laws of nature, should not aim for future growth but for sustainability in order to be able to satisfy the demand for raw materials, increasing disproportionately to the world's population expected to stand at nine billion by 2050.
Use of Renewable Raw Materials in the Chemical Industry – Beyond Sugar and Starch
Authors: Muffler K. , Ulber R.
Published: April 2008

Classical energy sources such as petroleum oil and natural gas make up the fundamental materials on which modern industrial chemical parks are based. According to the finite availability of these consuetudinary resources and due to the increasing demand for energy from developing countries and the related rise in prices of oil and natural gas, renewable resources must be considered as valuable alternatives. Discussions about climate change with regard to alternatives in energy production are preceded very fervidly but alternatives have to be examined from a matter‐of‐fact based economic and scientific point of view. Therefore, this review is focussed on alternative sources such as wood and other agricultural residues with respect to their potential as future energy resources as well as building blocks for chemical synthesis processes.
Phenols from Lignin
Authors: Kleinert M. , Barth T.
Published: April 2008

Lignin accounts for approximately 25–35 % of the organic matrix of wood and lignocellulosic biomass in itself is the most abundant renewable material on the planet. It has long been recognized as a potential feedstock for producing chemicals, fuels, and materials. Despite this excellent availabilty of lignin it is a low value compound and has so far mainly been used as energy source in combustion applications. Less than 5 % are being processed for other purposes. This article discusses the potential for an increased use of lignin as a renewable raw material, possible conversion routes towards monomeric phenolic compounds, and applications for these products. A brief overview about present state‐of‐the‐art is given and a high‐yielding, one‐step approach of producing alkylated phenolic compounds from lignin is presented.
Analysis and Evaluation of Technical and Economic Potentials of BtL‐Fuels
Authors: Vogel A. , Mueller‐Langer F. , Kaltschmitt M.
Published: April 2008

To meet the given political targets, biofuels of the next generation are developed in parallel to the existing first biofuel generation. However, the question on which of the various biofuel options discussed (e.g., bioethanol, synthetic biofuels, biohydrogen, biogas, biomethane) could contribute to which extend within the transportation sector in the future is not completely answered yet. Therefore, in this paper, selected options to produce BtL‐fuels via thermo‐chemical gasification are analyzed and assessed by means of technical and economic criteria. Furthermore, based on these results, aspects related to market implementation are discussed.
Theoretical Trends of Diffusion and Reaction into Tubular Nano‐ and Mesoporous Structures: General Physicochemical and Physicomathematical Modeling
Authors: Amatore Christian
Published: April 2008

A general and adaptable physicochemical model is presented to evaluate the mass transport within nanopores of mesoporous particles when the mass transport is coupled to heterogeneous kinetics occurring at active sites located onto the nanopore walls surface. The model framework encompasses almost all situations of practical interest in solutions and may be used for characterizing the kinetic rates and constants controlling the system under different sets of experimental conditions. Furthermore, it allows the delineation of simple effective parameters, which should be most useful for optimizing a given material in view of specific applications. For the sake of clarification the simplified model is presented and its results discussed by specializing it for cases where the reactions involve a simple adsorption of a target species on the nanopore immobilized sites as observed for inorganic sponges used in water decontamination. Yet it may easily be extended further to encompass a wider variety of situations where the sites immobilized onto the nanopore walls perform chemical or biochemical transformations as occur in supported catalysis in liquid solution.
Dimeric Capsules with a Nanoscale Cavity for [60]Fullerene Encapsulation
Authors: Park Seong Jin , Kwon Oh‐Hoon , Lee Kyung‐Sik , Yamaguchi Kentaro , Jang Du‐Jeon , Hong Jong‐In
Published: April 2008

The acid‐assisted and guest‐induced formation of superstructures was achieved by the addition of haloacetic acids to a toluene solution of the resorcin[4]arene derivatives 1 and [60]fullerenes. The formation of dimeric superstructures that encapsulated a nanosized guest molecule was observed when appropriate acids, such as haloacetic acids, and suitable guest molecules, such as [60]fullerenes, were co‐added to a toluene solution of cavitand 1 that has four pyridine units, whereas a complicated equilibrium between several species was detected without [60]fullerenes, and the formation of discrete superstructures was not monitored in the absence of haloacetic acids. The spectroscopic data indicate that the formed [60]fullerene‐encapsulated complexes have the structure of 2. These complexes are self‐assembled through pyridinium–anion–pyridinium interactions and by π–π and van der Waals interactions. The rate of decomplexation of 2 is estimated to be 3.1 s−1 from a 2D exchange NMR spectrum. The [60]fullerene encapsulation process can be controlled by modifying the amounts of acids used, changing the temperature of the system, altering the ratio of acid/base, and even through varying the solvent polarity. Moreover, the fluorescence spectra show band‐narrowing spectral changes and a retardation of the relaxation characteristics of isolated and isotropic [60]fullerenes, which indicates that the environmental change around [60]fullerene is induced upon its encapsulation.
The Mechanism of the (Bispidine)copper(II)‐Catalyzed Aziridination of Styrene: A Combined Experimental and Theoretical Study
Authors: Comba Peter , Lang Carolin , de Laorden Carlos Lopez , Muruganantham Amsaveni , Rajaraman Gopalan , Wadepohl Hubert , Zajaczkowski Marta
Published: April 2008

Experimental and DFT‐based computational results on the aziridination mechanism and the catalytic activity of (bispidine)copper(I) and ‐copper(II) complexes are reported and discussed (bispidine=tetra‐ or pentadentate 3,7‐diazabicyclo[3.1.1]nonane derivative with two or three aromatic N donors in addition to the two tertiary amines). There is a correlation between the redox potential of the copper(II/I) couple and the activity of the catalyst. The most active catalyst studied, which has the most positive redox potential among all (bispidine)copper(II) complexes, performs 180 turnovers in 30 min. A detailed hybrid density functional theory (DFT) study provides insight into the structure, spin state, and stability of reactive intermediates and transition states, the oxidation state of the copper center, and the denticity of the nitrene source. Among the possible pathways for the formation of the aziridine product, the stepwise formation of the two NC bonds is shown to be preferred, which also follows from experimental results. Although the triplet state of the catalytically active copper nitrene is lowest in energy, the two possible spin states of the radical intermediate are practically degenerate, and there is a spin crossover at this stage because the triplet energy barrier to the singlet product is exceedingly high.
Unterrichtsbezogene Vorstellungen von Lehramtsstudierenden der Chemie am Beginn ihres Studiums und ihre Einordnung
Authors: Markic Silvija , Eilks Ingo
Published: April 2008

Diese Studie über unterrichtsbezogene Vorstellungen von Lehramtsstudierenden der Chemie am Beginn ihres Studiums basiert auf der Analyse von Zeichnungen, in denen Studierende sich selbst als Lehrperson in einer für sie typischen Unterrichtssituation zeichnen und die dargestellten Aktivitäten und Ziele der Unterrichtssituation beschreiben. Das zu Grunde liegende Instrument und ein auf der Basis von Gegenstandsbezogener Theoriebildung (Grounded Theory) entwickeltes Auswertungsraster werden vorgestellt. Es werden ein Überblick über die Vorstellungen von 85 Lehramtsstudierenden der Chemie und eine Einordnung in den Zusammenhang von ähnlich großen Studierendengruppen der Physik, Biologie und des Sachunterrichts gegeben. Die Ergebnisse zeigen, dass die Studierenden der Chemie im Vergleich zu Biologie und Sachunterricht stärker lehrerzentrierte und sachstrukturorientierte Vorstellungen von Unterricht mit in ihr Studium bringen. Diese Ausprägung ist allerdings nicht so stark entwickelt, wie in der Physik. Konsequenzen für die Lehrerbildung werden diskutiert.
Ionenbildung durch Strom?
Authors: Marohn Annette
Published: April 2008

Schüler: „Ganz so blöd sind wir wohl doch nicht, wenn die Chemiker das damals auch nicht verstanden haben.”︁

Schülerin: „Wir sind aber über 100 Jahre weiter als die.”︁

Schüler: „Tja, es kann eben nicht jeder ein Arrhenius sein!”︁

(Dialog nach der Beschäftigung mit historischen Zitaten zur Arrheniusschen Ionenhypothese, in denen die Schüler ihre eigenen Vorstellungen wieder erkannten.)

Schülervorstellungen können überzeugend und gut begründet sein – allerdings sind sie zumeist auch schwer zu fassen und ausgesprochen widerstandsfähig gegenüber Veränderungen. Es fehlen Hilfen, wie Schülervorstellungen erkannt und in den Unterricht einbezogen werden können. Der Artikel beschreibt ein Unterrichtsverfahren, das nicht darauf abzielt, das Auftreten von Schülervorstellungen zu verhindern, sondern diese bewusst in den Unterricht einbezieht. Als Basis des Verfahrens dienen zwei empirische Studien, in denen die am häufigsten auftretenden Vorstellungen zu verschiedenen Themengebieten der Chemie erforscht wurden. Die im Rahmen der Studien entwickelten Aufgaben erhalten im Verlauf des Unterrichtsverfahrens zweierlei Funktion: Zum einen werden sie als Diagnoseinstrument eingesetzt, um Vorstellungen der eigenen Lerngruppe zu erforschen. Zum anderen dienen sie Schülern als Lernaufgaben, um sich eigener Vorstellungen bewusst zu werden und diese im Rahmen diskursiver und durch Lernmaterialien geleiteter Prozesse in Richtung der wissenschaftlich gültigen Vorstellungen weiter zu entwickeln. Der Artikel konzentriert sich auf Vorstellungen von Schülern über die Vorgänge in einfachen elektrolytischen Zellen und die Existenz von Ionen in wässrigen Lösungen. Er diskutiert mögliche Gründe für die beschriebenen Vorstellungen und zeigt als Besonderheit eine unmittelbare Parallele zu chemiegeschichtlichen Konzepten auf. Die historische Parallele führt zu einer Variation des Verfahrens: Sie dient als Motivation, die chemiegeschichtlichen Vorstellungen aus heutiger Sicht zu widerlegen und bewirkt damit implizit eine Festigung moderner wissenschaftlicher Konzepte.
Flow cytometry in plant breeding
Authors: Ochatt Sergio J.
Published: April 2008

Since the first report on the flow cytometric study of plant material 35 years ago, analyzing the nuclear DNA content of field bean, an ever increasing number of applications of FCM has been developed and applied in plant science and industry, but a similar length of time elapsed before the appearance of the first complete volume devoted to FCM of plant cells. Most published information on the uses of FCM addresses various aspects of animal (including human) cell biology, thus failing to provide a pertinent substitute. FCM represents an ideal means for the analysis of both cells and subcellular particles, with a potentially large number of parameters analyzed both rapidly, simultaneously, and quantitatively, thereby furnishing statistically exploitable data and allowing for an accurate and facilitated detection of subpopulations. It is, indeed, the summation of these facts that has established FCM as an important, and sometimes essential, tool for the understanding of fundamental mechanisms and processes underlying plant growth, development, and function. In this review, special attention is paid to FCM as applied to plant cells in the context of plant breeding, and some new and less well‐known uses of it for plants will be discussed. © 2008 International Society for Advancement of Cytometry
Multiparameter detection of apoptosis using red‐excitable SYTO probes
Authors: Wlodkowic Donald , Skommer Joanna , Hillier Chris , Darzynkiewicz Zbigniew
Published: April 2008

Functional assays allowing phenotypic characterization of different cell death parameters at a single‐cell level are important tools for preclinical anticancer drug screening. Currently, the selection of cytometric assays is limited by the availability of fluorescent probes with overlapping spectral characteristics. Following on our earlier reports on green and orange fluorescent SYTO probes, we provide herein further insights into applicability of novel red‐excitable SYTO stains (SYTO 17, 59–64) for multiparameter analysis of cell fate. In particular, SYTO 62 appears to be a spectrally favorable candidate. Using a correlative comparison between SYTO 16, Annexin V, YO‐PRO 1, and fluorescently labeled inhibitors of caspases (FLICA), we demonstrate the specificity of SYTO 62 in detection of apoptotic cell death. Used in conjunction with FLICA or Annexin V, SYTO 62 stain proved amenable for multivariate kinetic analysis of apoptotic events. Considering simplicity of staining protocols, low cost, and avoidance of spectral compensation problems, we expect that red‐excitable SYTO dyes will find a wide range of cytometric applications. © 2008 International Society for Advancement of Cytometry
A rapid flow cytometry test based on histone H2AX phosphorylation for the sensitive and specific diagnosis of ataxia telangiectasia
Authors: Porcedda Paola , Turinetto Valentina , Brusco Alfredo , Cavalieri Simona , Lantelme Erica , Orlando Luca , Ricardi Umberto , Amoroso Antonio , Gregori Dario , Giachino Claudia
Published: April 2008

Ataxia telangiectasia (A‐T) is a progressive neurodegenerative disease with onset in early childhood, caused by mutations in the ATM (ataxia‐telangiectasia mutated) gene. Diagnosis relies on laboratory tests showing high levels of serum alphafetoprotein, cell sensitivity to ionizing radiation (IR) and absence or reduced levels of ATM protein. Many tests, however, are not sufficiently sensitive or specific for A‐T, have long turnaround times, or require large blood samples. This prompted us to develop a new flow cytometry method for the diagnosis of A‐T based on the measurement of histone H2AX phosphorylation. We established normal ranges of histone H2AX phosphorylation after 2 Gy IR by testing T‐cell lines, lymphoblastoid cell lines (LCLs) and/or peripheral blood mononuclear cells (PBMCs) or both from 20 genetically proven A‐T and 46 control donors. To further evaluate the specificity and sensitivity of the test, we analyzed cells from 19 patients suspected of having A‐T, and from one Friedreich Ataxia, one Ataxia with Oculomotor Apraxia type 2, and one Nijmegen Breakage Syndrome patients. Phosphorylated histone H2AX mean fluorescence intensity of irradiated A‐T cells was significantly lower than that of healthy donors. The intrastaining, intraassay, and interassay imprecisions were ≤13.22%. Sensitivity and specificity were virtually 100% when the test was performed on PBMCs. Screening of 19 consecutive new patients with suspected A‐T classified 15 patients as non‐A‐T and four as A‐T; diagnosis of the latter four was subsequently confirmed by DNA sequencing to identify ATM mutations. The Friedreich Ataxia patient, the Ataxia with Oculomotor Apraxia type 2 patient and the Nijmegen Breakage Syndrome patient were classified as non‐A‐T. This flow cytometry test is very sensitive, specific and rapid, and requires only 2 ml of blood. It may thus be proposed for the early differential diagnosis of A‐T as an alternative to methods requiring the production of LCLs. © 2008 International Society for Advancement of Cytometry
Growth dynamics of mammalian cells monitored with automated cell cycle staining and flow cytometry
Authors: Sitton Greg , Srienc Friedrich
Published: April 2008

To accurately observe high‐frequency events during transient cell cycle kinetics, we have implemented a single step 15‐min DNA staining protocol using automated flow cytometry. This protocol was used to sample and to analyze a Chinese hamster ovary cell culture for the DNA distribution, viable cell concentration, apoptotic cell concentration, and light scattering properties every 25 min over 4.5 days in response to a nutrient deprivation and a nutrient upshift. After the nutrient deprivation and exposure to fresh growth medium, two populations of cells started proliferating at different times likely corresponding to cells leaving the G0 and G1 cell cycle phases. After a nutrient upshift in late exponential growth, a cell cycle arrest occurred at the G1/S and G2/M boundary. The resulting cell cycle and proliferation kinetics followed damped oscillations that directly reveal the average time cells spend in each cell cycle phase. The observed detailed dynamics of the cell cycle progression is made possible through the high‐frequency sampling enabled by automated flow cytometry. The approach should be useful in studying cell cycle perturbations in response to different environmental conditions resulting from exposure to specific nutrients or to drugs. © 2008 International Society for Advancement of Cytometry
Standardized method to minimize variability in a functional P2X7 flow cytometric assay for a multi‐center clinical trial
Authors: Korpi‐Steiner N. L. , Sheerar D. , Puffer E. B. , Urben C. , Boyd J. , Guadarrama A. , Schell K. , Denlinger L. C.
Published: April 2008

Background

Flow cytometric analysis of human P2X7 pore activity segregates variant from common P2RX7 genotypes and may serve as a biomarker for cancer, pain, inflammation, and immune responses to infection. Standardization is needed to accommodate variable sample age and instrumentation differences in a multicenter clinical trial.

Methods

CD14‐PE‐stained whole blood samples were treated with YO‐PRO‐1 combined with a P2X7 agonist (BzATP) or control, followed by the addition of PI after closure of the P2X7 pore. Recalled instrument settings from previous publications were used to adapt a standardized fluorescent particle‐adjusted set‐up method. Experiments were performed to compare the two methods while evaluating components of systematic variability and facilitating reliable processing of samples with varied ages.

Results

The median YO‐PRO‐1 fluorescence of BzATP‐treated samples had less variability when collected by the bead‐adjusted method and was less influenced by the compensation strategy used. The average day‐to‐day coefficient of variance for assessments of P2X7 pore activity by this method was 0.11 ± 0.04, and the exclusion of nonviable cells was found to accommodate samples aged up to 4 days after phlebotomy. The bead‐adjusted set‐up method produced measurements differing by only 2.0% ± 1.5% on two analog cytometers, and within similar decades when comparing analog to digital instruments.

Conclusions

These results provide a standardized method for quantitative flow cytometric analysis of P2X7 receptor phenotypes in blood monocytes with minimal intralaboratory variation and potential for interlaboratory comparisons that can greatly facilitate multicenter functional genomic clinical studies. © 2008 Clinical Cytometry Society