bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfaces between 4H-SiC and SiO2: Microstructure, nanochemistry, and near-interface traps
Authors: Pippel Eckhard , Woltersdorf Jörg , Ólafsson Halldor Ö. , Sveinbjörnsson Einar Ö.
Published: December 2004

We report on electrical and microscopic investigations aimed to clarify the origin of near-interface traps (NITs) in metal–silicon dioxide–4H-silicon carbide structures. Using capacitance–voltage and thermal dielectric relaxation current (TDRC) analysis we investigated NITs close to the 4H-SiC conduction-band edge in differently prepared thermal and deposited oxides and found that the traps give rise to two characteristic TDRC signatures belonging to two groups of trap levels. The total trapped charge exceeds 1×1013cm−2. The observed density and energy distribution of these traps are nearly identical in all thermal and deposited oxides investigated, suggesting that the NITs belong to intrinsic defects at the SiO2∕SiC interface which are readily formed during oxide deposition or thermal oxidation of 4H-SiC. Using high-resolution electron microscopy combined with nanochemical analysis (electron energy-loss near-edge spectroscopy and energy-filtered transmission electron microscopy) we investigated the SiO2∕SiC interface in samples receiving reoxidation and did not find any indication of graphitic regions at or near the SiO2∕SiC interface or in the bulk silicon dioxide within a detection limit of 0.7nm. In addition, no amorphous carbon accumulation was observed near the SiO2∕SiC interface. The overall results strongly suggest that the NITs near the 4H-SiC conduction band are not related to carbon structures in the SiO2∕SiC interlayer.
Spectroscopic detection of carbon nanotube interaction with amphiphilic molecules in epoxy resin composites
Authors: Bassil Ayman , Puech Pascal , Landa Georges , Bacsa Wolfgang , Barrau Sophie , Demont Philippe , Lacabanne Colette , Perez Emile , Bacsa Revathi , Flahaut Emmanuel , Peigney Alain , Laurent Christophe
Published: December 2004

Incorporation of carbon nanotubes into epoxy resin composites has the effect of increasing electrical conductivity at low percolation levels. An amphiphilic molecule such as palmitic acid has been used to increase the surface contact area and to improve the dispersion of the carbon nanotube bundles in the prepolymer. The chemical environment of the dispersed nanotubes has been probed using vibrational Raman spectroscopy. Spectroscopic Raman maps on sample surfaces (60×60μm2) with ratios of nanotubes to palmitic acid varying from 1:2 to 2:1 by weight, have been recorded to test the uniformity of the dispersion. Substantial spatial inhomogeneities have been observed in the G-band shift and an additional spectral band at 1450cm−1. The 1450cm−1 band has been attributed to the CH3 group of the amphiphilic molecules adsorbed onto the nanotube surface. The maps are correlated with the measured electrical conductivity values. The highest conductivity has been observed for the best dispersed nanotubes and nanotubes with the highest degree of interaction.
DUALITY IN FUZZY SIGMA MODELS
Authors: BALACHANDRAN A. P. , IMMIRZI GIORGIO
Published: December 2004

Nonlinear "sigma" models in two dimensions have BPS solitons which are solutions of self- and anti-self-duality constraints. In this paper, we find their analogues for fuzzy sigma models on fuzzy spheres which were treated in detail by us in earlier work. We show that fuzzy BPS solitons are quantized versions of "Bott projectors," and construct them explicitly. Their supersymmetric versions follow from the work of S. Kürkçüoǧlu.
INCLUDING DISPERSION AND ATTENUATION IN TIME DOMAIN MODELING OF PULSE PROPAGATION IN SPATIALLY-VARYING MEDIA
Authors: NORTON GUY V. , NOVARINI JORGE C.
Published: December 2004

Modeling of acoustic pulse propagation in nonideal fluids requires the inclusion of attenuation and its causal companion, dispersion. For the case of propagation in a linear, unbounded medium Szabo developed a convolutional propagation operator which, when introduced into the linear wave equation, accounts for attenuation and causal dispersion for any medium whose attenuation possesses a generalized Fourier transform. Utilizing a one dimensional Finite Difference Time Domain (FDTD) model Norton and Novarini showed that for an unbounded isotropic medium, the inclusion of this unique form of the convolutional propagation operator into the wave equation correctly carries the information of attenuation and dispersion into the time domain. This paper addresses the question whether or not the operator can be used as a basic building block for pulse propagation in a spatially dependent dispersive environment. The operator is therefore used to model 2-D pulse propagation in the presence of an interface separating two dispersive media. This represents the simplest description of a spatially dependent dispersive media. It was found that the transmitted and backscattered fields are in excellent agreement with theoretical expectations demonstrating the effectiveness of the local operator to model the field in spatially dependent dispersive media. [Work supported by ONR/NRL.]
A NOTE ON "COMPUTATIONAL AEROACOUSTICS EXAMPLES SHOWING THE FAILURE OF THE ACOUSTIC ANALOGY THEORY TO IDENTIFY THE CORRECT NOISE SOURCES" BY CKW TAM
Authors: PEAKE N.
Published: December 2004

In a recent paper (J. Computational Acoustics10 (2002) 387–405) Tam has claimed that the famous Lighthill Acoustic Analogy predicts the wrong flow field for the simple problem of the propagation of a normal shock. However, we show that Tam has misinterpreted the results of his analysis, and that when this error is corrected the results of the Acoustic Analogy are brought into exact agreement with the well-known Rankine–Hugoniot solution of the Euler equations.
MULTI-CHANNEL ELECTRO-OPTIC POLYMER MODULATOR BASED ON A NOVEL SIDE-CHAIN POLYMER
Authors: PARK SUNTAK , JU JUNG JIN , DO JUNG YUN , PARK SEUNG KOO , LEE MYUNG-HYUN
Published: December 2004

A multi-channel optical modulator with 16 independent modulators is fabricated using an electro-optic (EO) polymer with a large EO coefficient and good thermal stability. The 16-channel modulator has lumped type electrodes for modulation and heaters for thermal biasing. The device has good uniform modulation characteristics between individual modulators. The deviation of half-wave voltages is 0.2 V and that of insertion losses about 1 dB. Crosstalks range from -28 to -36 dB and extinction ratios are more than 21 dB.
NONLINEAR FREQUENCY CONVERSION BY RAMAN COHERENCE PREPARED IN SOLID HYDROGEN FILM
Authors: LEE G. J. , HARA K. , KATSURAGAWA M. , HAKUTA K.
Published: December 2004

We investigated the Raman coherence characteristics in the solid hydrogen film deposited on a sapphire substrate. By using Raman coherence prepared with two single-frequency pulsed lasers, we generated the multiorder coherent Raman sidebands in solid hydrogen film. High-order Raman sidebands were obtained under strong pumping conditions (≥230 MW/cm2). The generated anti-Stokes(AS)–Raman sidebands extended from ultraviolet (292 nm for AS5 band) to visible (565 nm for AS1 band) region. The multiorder Raman sideband generation is thought to be due to the parametric coupling of pump and coupling lasers. The frequency conversion efficiency shows the maximum (14%) at the pumping intensity of 360 MW/cm2. From the experiment that makes the multimode probe beam beat with the prepared Raman coherence, we found that the prepared Raman coherence replicates the probe beam to its Raman sidebands.
TWO-PHOTON ABSORBING PHENYLENEVINYLENE DERIVATIVE HAVING SILYLOXY MOIETIES IN DONOR UNITS
Authors: KIM MOON SOO , YANG HYUN-KWAN , KIM RAN HEE , LEE KWANG-SUP , CHA MYOUNGSIK , CHOI HAEYOUNG , SUN HONG-BO , KAWATA SATOSHI
Published: December 2004

Two-photon absorbing phenylenevinylene derivative having silyloxy moieties in electron donor units (EHSEA) was prepared. The two-photon absorption (TPA) cross-section value of this chromophore was found to be 1.93×10-48 cm 4 sec / photon at 740 nm by using TPA-induced fluorescence method with 80 fs pulse laser. The nonlinear measurement with ns scale pulses has indicated that EHSEA exhibits an efficient optical power limiting activity. We have obtained micropatterns with high resolution by TPA-induced polymerization using EHSEA as a photosensitizer.
THICK PHOTORESIST ORIGINAL MASTER: A NEW TOOL FOR FABRICATION OF POLYMERIC OPTICAL WAVEGUIDES WITH LARGE CORE BY HOT EMBOSSING
Authors: MIZUNO HIROTAKA , SUGIHARA OKIHIRO , KAINO TOSHIKUNI , OHE YUKA , OKAMOTO NAOMICHI , HOSHINO MASAHITO
Published: December 2004

A simple and low-cost fabrication method of polymeric optical waveguides with large core sizes for plastic optical fibers is presented. The waveguides are fabricated by hot embossing with a rectangular ridge ultraviolet (UV)-cured epoxy resin stamper. The stamper is fabricated by replication of a rectangular groove mold that is made from silicone rubber replicated from a rectangular ridge original master made from thick photoresist (SU-8). A rectangular ridge shape of the original photoresist master of 1 mm size was realized by using a flattening process, which involves hot embossing before the exposure process and using a UV-cut filter during the exposure process.
NOVEL PHOTOPOLYMERS COMPOSED OF THERMOPLASTIC AND PHOTOREACTIVE BINDERS FOR HOLOGRAPHIC APPLICATION
Authors: YOON HYUK , CHOI DONG HOON , CHO MIN JU , KIM JAE HONG , LEE GEON JOON , LEE SEUNG HWAN , PAEK SANG-HYON
Published: December 2004

New photopolymers were designed and prepared using the thermoplastic and photoreactive binders. Poly (vinylacetate-co-vinylalcohol) was used as a thermoplastic polymer binder and 3-isopropenyl-α,α-dimethylbenzyl isocyanate (m-TMI) was tethered to the side chain of the above polymer. The holographic gratings were successfully fabricated in these photopolymer film samples by conventional optical interference method. The dynamic behaviors of the grating formation were studied with the change of exposure intensity. The effect of photoreaction between the polymer binder and the newly-formed polymer in the constructive region on the diffraction behavior and its stability was also investigated.
PREPARATION OF MEROCYANINE SALTS BY TREATMENT OF ACIDS ON SPIROPYRANS AND INVESTIGATION ON THEIR PHOTOCHROMIC BEHAVIORS
Authors: KIM DONG WOOK , KANG HEEKYOUNG , LEE YOUN-SIK , KIM EUNKYOUNG , KANG YONGKU , LEE CHANGJIN
Published: December 2004

Merocyanine salts were prepared and their photochromic behavior investigated. The salts were prepared from a solution of spiropyrans in the presence of acids such as toluenesulfonic acid and dodecylbenzene sulfonic acid under irradiation of UV light and heat. The 1H NMR spectrum confirmed the chemical structure of the merocyanine salts. The salt showed an absorption peak at 422 nm, which was blue-shifted as compared with the absorption peak at 578 nm of the merocyanine form of spiropyran. The salt form was quite stable and virtually exhibited a negative photochromism. The salt showed better fatigue resistance than the spiropyran. The photoinduced refractive index change for the salt films by a prism coupler method was estimated to be as large as 0.0055.
FABRICATION OF PATTERNED ELECTROLUMINESCENT POLYMERS WITH MICROCONTACT PRINTING
Authors: PARK MIN JU , CHOI WON MOOK , PARK O OK
Published: December 2004

For most practical applications, it is essential to fabricate micro- or nano-scale polymer electroluminescent (EL) devices and pixel arrays. Microcontact printing, which uses a patterned elastomer (usually PDMS) as the mold to generate or transfer the pattern offers immediate advantages. Here we describe a method of patterning polymeric EL materials based on microcontact printing using PDMS mold. In this technique, we use the self-assembled monolayer (SAM) system of alkanephosphonic acids on ITO substrate, and patterned EL polymer is formed on the SAM-modified ITO substrate.
Activation of the Arp2/3 complex by N-WASp is required for actin polymerization and contraction in smooth muscle
Authors: Zhang Wenwu , Wu Yidi , Du Liping , Tang Dale D. , Gunst Susan J.
Published: December 2004

Contractile stimulation has been shown to initiate actin polymerization in smooth muscle tissues, and this actin polymerization is required for active tension development. We evaluated whether neuronal Wiskott-Aldrich syndrome protein (N-WASp)-mediated activation of the actin-related proteins 2 and 3 (Arp2/3) complex regulates actin polymerization and tension development initiated by muscarinic stimulation in canine tracheal smooth muscle tissues. In vitro, the COOH-terminal CA domain of N-WASp acts as an inhibitor of N-WASp-mediated actin polymerization; whereas the COOH-terminal VCA domain of N-WASp is constitutively active and is sufficient by itself to catalyze actin polymerization. Plasmids encoding EGFP-tagged wild-type N-WASp, the N-WASp VCA and CA domains, or enhanced green fluorescent protein (EGFP) were introduced into tracheal smooth muscle strips by reversible permeabilization, and the tissues were incubated for 2 days to allow for expression of the proteins. Expression of the CA domain inhibited actin polymerization and tension development in response to ACh, whereas expression of the wild-type N-WASp, the VCA domain, or EGFP did not. The increase in myosin light-chain (MLC) phosphorylation in response to contractile stimulation was not affected by expression of either the CA or VCA domain of N-WASp. Stimulation of the tissues with ACh increased the association of the Arp2/3 complex with N-WASp, and this association was inhibited by expression of the CA domain. The results demonstrate that 1) N-WASp-mediated activation of the Arp2/3 complex is necessary for actin polymerization and tension development in response to muscarinic stimulation in tracheal smooth muscle and 2) these effects are independent of the regulation of MLC phosphorylation.
Inflammation and Vascular Calcification
Authors: Moe Sharon M. , Chen Neal X.
Published: December 2004

Both vascular calcification and inflammation are common in patients with chronic kidney disease (CKD). In patients on dialysis, there is increased coronary artery and peripheral artery calcification compared to the general population. Both intimal (atherosclerotic) and medial calcification in CKD patients are associated with increased morbidity and mortality. Vascular calcification is an active cell-mediated process, and likely reflects a transformation of vascular smooth muscle cells to osteoblast-like cells. Pooled uremic serum can induce this transformation, but the mechanism by which it does so is not yet clear. Several mediators of inflammation such as oxidation, carbonyl stress, C-reactive protein, and cytokines may directly stimulate vascular calcification. In addition, inflammation itself reduces fetuin-A, a naturally occurring inhibitor of vascular calcification which binds excess mineral in serum. The combination of the acceleration of vascular calcification together with impaired defense mechanisms creates a uremic milieu primed for extra-osseous calcification.
Reflections on Relevance: Psychotherapy and Psychosomatics in 2004
Authors: Balon Richard
Published: December 2004

Relevance of an article is a highly desirable yet hardly predictable quality at the time of its publication. Article relevance is frequently measured by the impact factor of the journal where the article is published. Furthermore, impact factor, citation index and citation analysis are used as a measure of research progress and scientific wealth of a nation. The wisdom and significance of this approach to relevance is debatable and thus discussed here. In 2004, Psychotherapy and Psychosomatics published a variety of articles which, in the author’s view, are clinically relevant. Several selected clinically relevant issues reviewed in this article include: the conceptualization of fibromyalgia as a stress disorder; the psychosocial impact and psychosocial interventions in cancer; the impact of alexithymia on patient care; the possible relationship between depression and nutrition (namely intake of folate and pyridoxal phosphate); the significance of hypercoagulability in panic-like anxiety; the questionable value of single isomer drugs, and the relevance and adequacy of clinimetrics versus psychometrics in clinical research. The reviewed issues seem to be relevant to clinical practice, research or both, but also to our critical thinking, and the critical review of the developments in psychiatry and psychology.
Relationship between Alexithymia and Panic Disorder: A Longitudinal Study to Answer an Open Question
Authors: Marchesi Carlo , Fontò Stefania , Balista Chiara , Cimmino Carmen , Maggini Carlo
Published: December 2004

Background: In the present study, we evaluated whether patients with panic disorder (PD) in complete remission were more alexithymic than normal controls. Methods: Fifty-two PD patients (both during the acute phase of the disorder and after at least 2 months of complete remission) and 52 age- and sex-matched normal subjects completed the Toronto Alexithymia Scale-20 and the Hamilton Rating Scales for Anxiety (Ham-A) and for Depression. Results: A higher rate of alexithymia was found in PD patients than in controls (3.8%) both during the acute phase (44.2%; p < 0.001) and after remission of the disorder (21.2%; p = 0.008). During remission, PD patients showed: (1) Ham-A scores significantly higher than controls (p < 0.001); (2) only an elevation of the ‘difficulty in identifying feeling’ (DIF) dimension of alexithymia, and (3) a positive relationship between Ham-A scores and DIF levels (p < 0.001). Conclusion: After remission of panic attacks, phobic avoidance and anticipatory anxiety, PD patients are more alexithymic (even though the levels of alexithymia decreased after the resolution of the acute phase of PD) and anxious than controls. This finding might be explained by an overlap between cognitive aspects of PD and the DIF dimension of alexithymia, since alexithymic and anxious levels are positively related.
Plasma Levels of Antioxidants Are Not Associated with Alzheimer’s Disease or Cognitive Decline
Authors: Engelhart Marianne J. , Ruitenberg Annemieke , Meijer John , Kiliaan Amanda , van Swieten John C. , Hofman Albert , Witteman Jacqueline C.M. , Breteler Monique M.B.
Published: December 2004

Antioxidants prevent oxidative stress that possibly causes neuronal loss in Alzheimer’s disease (AD). We examined whether high plasma levels of the antioxidant vitamins A and E were associated with lower prevalence of AD or cognitive decline (CD). We performed a cross-sectional study within the Rotterdam Study. In an univariate model, higher levels of vitamins A and E were significantly associated with lower prevalence of AD. However, when additional adjustments were made for important confounders, such as age, gender and total cholesterol, the relation substantially weakened – odds ratios per standard deviation increase were 0.87 (95% CI 0.64–1.19) for vitamin A and 0.94 (95% CI 0.60–1.48) for vitamin E. Antioxidants were not related to CD in non-demented subjects. Our findings suggest no association between plasma levels of vitamin A and E and AD or CD.
Dementia in First-Degree Relatives of Patients with Frontotemporal Dementia
Authors: Gräsbeck A. , Horstmann V. , Nilsson K. , Sjöbeck M. , Sjöström H. , Gustafson L.
Published: December 2004

Several studies have found a clustering of dementia in relatives of patients with frontotemporal dementia (FTD). This study analysed the familial aggregation of FTD specifically as well as the occurrence of dementia in general in first-degree relatives of patients with FTD. A family history study was carried out on 478 first-degree relatives of 74 index patients suffering from FTD. Cases of organic dementia and of FTD were diagnosed according to internationally accepted diagnostic criteria. Age- and sex-specific incidences of organic dementia and of FTD were calculated as was the proportion of FTD in relation to organic dementia in general; comparisons with clinical and population studies were made. There was a tenfold increase in the incidence of FTD in the first-degree relatives of FTD patients compared with the incidence of FTD in a population study. The proportion of FTD in relation to all types of organic dementia was much higher in relatives of FTD patients compared to the corresponding proportions in clinical and population-based studies. There was a small, non-significant difference between the present family history study and the population studies as regards the incidence of organic dementia. The findings suggest that hereditary and/or shared environmental factors are strongly involved in the aetiology of FTD. There were no indications of familial clustering of organic dementia in general in relatives of FTD patients.
Prognostic Significance of Delirium in Frail Older People
Authors: Pitkala Kaisu H. , Laurila Jouko V. , Strandberg Timo E. , Tilvis Reijo S.
Published: December 2004

Our aim was to investigate the long-term prognosis of delirium in the frailest elderly, and to clarify whether delirium is just a marker of the underlying severe disease. We used logistic regression analysis to determine the independent prognostic significance of delirium. A representative sample of 425 patients (≥70 years) in acute geriatric wards and nursing homes were assessed at baseline and followed up for 2 years. DSM-IV was used for classification. The prevalence of delirium at baseline was 24.9% (106/425). The prognosis of delirium was poor: mortality at 1 year was 34.9 vs. 21.6% in nondelirious subjects (p = 0.006), and at 2 years 58.5 vs. 42.6% (p = 0.005). Among home-dwelling people at baseline, 54.4% of the delirious vs. 27.9% of others were permanently institutionalized within 2 years (p < 0.001). In logistic regression analysis, delirium was an independent predictor for mortality at 1 year (OR 1.86, 95% CI 1.1–3.1), at 2 years (OR 1.76, 95% CI 1.1–2.8), and for permanent institutionalization (OR 2.45, 95% CI 1.2–4.9). Delirious patients with prior dementia tended to have a better prognosis than those without.
Regional Differences in the Use of Out-Patient Services by Stroke Patients after Hospitalisation
Authors: Boter Han , de Haan Rob J. , Rinkel Gabriël J.E.
Published: December 2004

Background: To improve the quality of life in stroke patients, outreach care programmes are developed and assessed for effectiveness. The generalisability of the trials’ results is uncertain since information on the comparability of the conventional out-patient services is lacking. This study intended to assess the use of 11 types of conventional out-patient services by stroke patients in the United States and a predefined set of Western European countries. Methods: Review of the literature from 1990 to 2001. Results: We found 11 studies, which contained data on 1,875 patients of 6 countries. Large differences in the use of out-patient services within and between countries prohibited pooling of the data. Conclusions: The paucity of data on the use of conventional out-patient services by stroke patients and the regional differences found do not substantiate generalisability of the results from studies on outreach care for stroke patients.
Transdermal Suctioning Technique for Serial Sampling of Interstitial Fluid in Newborn Infants
Authors: Hansen-Pupp I. , Håkansson K. , Polberger S. , Svedman P.
Published: December 2004

Overview: Use of a suction-induced epidermal mini-erosion for serial sampling of dermal interstitial fluid (IF) in 16 newborn infants with gestational age ranging from 24 to 42 weeks is reported. Results: The mini-erosion formed reproducibly and electron microscopy showed that the split was located within the epidermis. IF was sampled serially by suctioning during 1–3 days without signs of stress or pain. IF sample volumes (10–50 µl) did not decrease with time. Glucose values in IF and blood were correlated (rs = 0.542; p = 0.000). IF glucose was lower than blood glucose on all 3 days. The epidermis regenerated within 4 ± 0.9 days (mean, SD) after sampling was terminated. There were no complications. Conclusion: Serial transdermal sampling was performed without stress or pain in newborn infants. Systemic and temporal differences between glucose measured in IF and blood were observed.
The Relationship between Snow Accumulation at Mt. Logan, Yukon, Canada, and Climate Variability in the North Pacific
Authors: Rupper Summer , Steig Eric J. , Roe Gerard
Published: December 2004

An ice core from Mt. Logan, Yukon, Canada, presents an opportunity to evaluate the degree to which ice core accumulation records can be interpreted as meaningful measures of interannual climate variability. Statistical analyses and comparisons with synoptic station data are used to identify the physical relationships between Mt. Logan ice core accumulation data and large-scale atmospheric circulation. These analyses demonstrate that only the winters of high accumulation years have a robust connection with atmospheric circulation. There are no consistent relationships during anomalously low and average accumulation years. The wintertime of high accumulation years is associated with an enhanced trough–ridge structure at 500 hPa and in sea level pressure over the northeast Pacific and western Canada, consistent with increased southerly flow bringing in warmer, moister air to the region. While both storm (i.e., 2–6 days) and blocking (i.e., 15–20 days) events project onto the same climate pattern, only the big storm events give rise to the dynamical moisture convergence necessary for anomalous accumulation. Taken together, these results suggest that while the Mt. Logan accumulation record is not a simple record of Pacific climate variability, anomalously high accumulation years are a reliable indicator of wintertime circulation and, in particular, of northeast Pacific storms.
Aufnahme von Kohlenwasserstoffen durch Hefen (Teil I)
Authors: Sattler K. , Wünsche L.
Published: December 2004

The uptake of hydrocarbons by yeasts is measured by gravimetric determination of intracellular accumulated N‐free compounds as well as by detection of tritium‐labeled hydrocarbons. The aim of the investigations is to compare the uptake of n‐alcanes and aromatics with respect to the conditions of yeast fermentation on gas oil. Aromatics in comparison to n‐alcanes are taken up in very little amounts. The uptake of n‐alcanes is dependent on the chain length. According to increasing chain length in the range of C10 – C16 the velocity of uptake is increased whereas the optimal pH‐value is decreased.

In the presence of dimethylsulfoxide the uptake of n‐alcanes is markedly increased whereas the uptake of aromatics is decreased. A mechanism of hydrocarbon uptake is discussed characterized by obligate participation of metabolic active cells and hydrocarbon selectivity.
Einfluß von Zustandsvariablen auf die Erhaltungs‐ und Verbrauchskoeffizienten bei mikrobiellen Prozessen
Authors: Schneider J. D.
Published: December 2004

It is shown for different examples of microorganisms growth in continuous flow culture the influence of process variables (temperature, H+‐concentration and changes of the chemical composition of fermentation medium) on the coefficients of maintenance and substrate consumption.

The maintenance coefficient is increased exponentially with increasing temperature or H+‐concentration.

The minimum maintenance coefficient is obtained when the growth rate is limited by carbon sources.

Other growth limitations or change of chemical composition in the medium lead to rising of maintenance coefficient but not in each case to increasing of specific C‐substrate consumption at lower residence time, especially.
Zur Struktur von Bakteriophagen aus enzymproduzierenden Bacillus‐Kulturen
Authors: Grunow R. , Schönherr M. , Taubeneck U. , Zimmermann I.
Published: December 2004

Aus Fermentationen mit Bacillus subtilis, die zum Zwecke der Synthese extrazellulä rer Enzyme angesetzt wurden, konnten verschiedentlich Bakteriophagen isoliert werden. Die auf Grund der Wirtsbereiche differierenden Einzelplaqueisolate wurden elektronenmikroskopisch untersucht. Die Partikel waren sehr verschieden in der Größe und in der morphologischen Struktur. Sie gehörten damit verschiedenen Gruppen von Bacillus‐Phagen an, die durch die Standardphagen SPO1, Ø29 und PBS1 reprä sentiert werden. Außerdem wurde ein Phage mit einem oktaedrischen Kopf gefunden. Aus einem enzymbildenden Bacillus‐Stamm konnten nach Infektion mit dem PBS1‐ä hnlichen Phagen PZ‐F Ghosts mit oktaedrischen Köpfen sowie nach Induktion mit Mitomycin C komplette und defektive Phagen freigesetzt werden.
Effect of trace elements and vitamins on the growth of Methanosarcina barkeri
Authors: Scherer P. , Sahm H.
Published: December 2004

Growth of Methanosarcina barkeri on methanol as energy source was found to be dependent on cobalt and molybdenum. In the presence of 10−6 M Co and 5 × 10−7M Mo optimal growth occurred. Furthermore it could be demonstrated that nickel and selenium each in a concentration of 10−7 M stimulated the growth of this methanogenic bacterium while the following elements tested in the range of 10−7 M to 10−3 had no influence: B, Cr, Cu, Mn, Pb. The requirement of Co and Ni for optimal growth are in accordance with the results that the cells contain the Co containing corrinoid Factor III (0.1 – 0.2 mg 5‐hydroxylbenzimidazolylcyanocobamide per g wet cells) and Factor F430, a nickel component. Studies on the vitamin dependency of M. barkeri showed that this strain needs only the vitamin riboflavin for the growth in a defined medium. Under these conditions a cell density of 2.6 g dry cells/l could be obtained in a fed batch culture.
Synthese und Eigenschaften von an DEAE‐Cellulose immobilisierter Aldehydoxydase aus Schweineleber
Authors: Kloossek P. , Kirchberger J. , Kurth J.
Published: December 2004

Aldehyde oxidase from pig liver was adsorptively bound to DEAE‐cellulose. The data of immobilization and the properties of the immobilized enzyme are reported. Its maximum half‐life is 36 days. The pH‐optimum is displaced toward lower pH‐values and independent from the substrates proved. Temperature optimum and substrate specifity, however, don't change during immobilization. Contrary to the soluble enzyme the aldehyde oxidase adsorbed to DEAE‐cellulose displays a two‐phase ARRHENIUS plot.
Das Autoselect‐System – ein Automatensystem zur Selektion von Antibiotikaproduzenten. IV. Achtfach‐Verdünnungsautomat
Authors: Schicht G. , Peissker M. , Steininger H. , Knöll H.
Published: December 2004

As a part of the Autoselect‐system an eightfold diluter is described. Cassettes with 64 tubes are placed on the carriage of the machine and moved automatically in eight steps. One of the cassettes is loaded with separated samples in 64 tubes and the other one with 64 empty tubes. When the carriage stops, a defined volume of samples is exhausted by eight pipettes, mounted on a bridge spanning over the ground unit from left to right, and after beeing moved to the second cassette the pipettes deliver the samples into a row of empty tubes. At the same time by eight syringes mounted on both sides of the machine a defined volume of buffer is delivered through tubes and canules. By this way all samples can be diluted in two minutes.
Erzeugung eines zellwandlytischen Enzymkomplexes aus Arthrobacter GJM‐I zur Herstellung von Protoplasten aus Candia spec. H
Authors: Häaussler O. , Wisniewski H.‐G , Röber B. , Reuter G.
Published: December 2004

Growing conditions have been found out for the bacterium Arthrobacter GJM‐I to produce a lytic enzyme system, which converts cells of the yeast Candida spec. H to protoplasts quickly and in a good yield. Estimating the activities of α‐mannanase and β‐glucanase we found out the optimal culture time to gain the lytic enzyme system from the culture filtrate. It was shown that radioactive labeling of the yeast cells makes it possible to estimate quantitatively the conversion to protoplasts and the simultaneous lysis. The obtained lytic enzyme system can substitute the snail cnzyme system which was used for cell conversion of Candida spec. H to protoplasts till now.
Immobilization of β‐glucosidase on an inorganic carrier
Authors: Lomako O. V. , Menyailova I. I. , Nakhapetian L. A. , Kozlovskaya L. I. , Rodionova N. A.
Published: December 2004

The enzymatic hydrolysis of cellobiose, an important intermediate of the decomposition of cellulose containing materials, with immobilized β‐glucosidase preparations from Geotrichium candidum, Trichoderma lignorum and Aspergillus foetidus was examined

At first it was the aim to prepare from differently purified samples with different specific cellobiase activities high active preparations on the basis of the inorganic carrier Silochrom S‐80. Characteristics e.g. thermal stability and temperature and pH optimum of immobilized preparations were compared with those of soluble preparations

Kinetics of cellobiose hydrolysis by immobilized enzyme preparations were studied.
Extrazelluläre Lipase aus Acinetobacter calcoaceticus
Authors: Haferburg D. , Kleber H.‐P.
Published: December 2004

Cell‐free growth liquor of Acinetobacter calcoaceticus 69‐V contains an extracellular lipase. Its activity depends on growth phase and carbon source. During growth on acetate or succinate the activity ist low or zero, respectively. Growth on alkanes causes an increase in the extracellular lipase activity. Activity reaches maximum values during the exponential phase of growth which significantly decrease in the stationary phase

During the growth on alkanes some surfactants (Tauroglycocholate, Triton X‐405) stimulate the excretion of the enzyme and some other (Tween, Brij, Triton X‐100) inhibit the lipase and growth of cells, respectively

Air‐water and alkane‐water interfaces inhibit the lipase activity. During starvation of the bacteria grown on alkanes lipase is excreted in the starvation medium.
Die Wirkung des chemischen Insektizids Fekamatribufon EC‐50 auf Pflanzenschutzpräparate auf basis bacillus thuringiensis
Authors: Iliewa Sw. , Stojanow Iw. , Welonow P.
Published: December 2004

There is treated the combined apply of chemical and biological plant protection preparations as well as their reciprocal effect. Purpose of this work is to investigate the effect of the chemical preparation Fekamatribufon EC‐50 (butylat‐0,0‐dimethyl‐II‐butyryloxy‐2,2,2‐trichlorethylester of phosphonic acid) on the spores of Bacillus thuringicnsis, var. dendrolimus and var. Berliner. The electronic‐microscopical investigations determine that the chemical insecticid Fekamatribufon EC‐50 accelerates the lysying of the spore structural elements of investigated Bacillus strains. The results of these investigations prove the incompatibility of the preparation Fekamatribufon EC‐50 in concentrations of 0.6–1.2% (Water solution) when it is combined with the microbial preparations Dendrobacillin and Türicid.

The above mentioned results present that the combined apply of chemical in ecticids with microbial preparations as plant protection means have obligatory to be preseded bysexact determination of their reciprocal effect.
Gewinnung und Charakterisierung von Proteasen aus Thermoactinomyces vulgaris. VI. Mitt. Zur Herstellung eines Trockenpraparates im Labor‐ und kleintechnischen Mnßstab unter besonderer Berücksichtigung des Öleinflusses
Authors: Leuchtenberger A. , Täufel A. , Ruttloff H.
Published: December 2004

A dried proteolytic enzyme preparation “Thermitase” is produced of the cultural solution of Thermoactinomyces vulgaris. The procedure comprises concentration, sedimentation, ethanol and sodiumsulfate precipitation and drying in laboratorial and semitechnical scale.

The elimination of rape seed oil which impairs the salt sedimentation was specially taken into account. A certain sedimentation procedure using caoline or a aqueous solution of CaCl2 and Na2HPO4 or filtration was elaborated to eliminate the lipid components in the concentrated solution.

The method is convenient to get good yields of the thermostable protease.
Möglichkeiten der Gewinnung von Koppelprodukten der mikrobiellen Eiweißsynthese auf der Basis von Kohlenwasserstoffen
Authors: Sattler K. , Wünsche L.
Published: December 2004

The mass production of SCP on the base of hydrocarbons opens the possibility to get a complex of further substances. It is distinguished between by‐products – belonging to essential nonprotein – structures of the growing cell and the so – called coupled products accumulating intra – or extracellularly by means of regulation. An important principle of SCP‐coupled synthesis of products is the use and the maintenance of proportionality between the growth rate and cell concentration of the producing cells and the accumulation of products. As examples are discussed: fermentation by yeasts and bacteria on the base of n‐alkanes, methane and methanol in connection with products as fatty acids, poly‐β‐hydroxybutyric acid, citric and gluconic acid.
Spezielle Aspekte der nichtsterilen Hefeproduktion auf der Basis von Kohlenwasserstoffen
Authors: Brendler W. , Bauch J. , Lübbert G. A. , Wünsche L. , Hedlich R. , Triems K. , Shdannikowa E. N.
Published: December 2004

Some aspects of the nonsteril yeast production are shown by a process with the alkane utilizing yeast Lodderomyces elongisporus D EH 15. Thereby an accompanying flora developes besides the yeast culture. The accompanying flora is using a lot of biogenic substances which are lysis products or extracellular metabolites. The dynamics of the development of the accompanying flora are shown, some remarks are made concerning the interactions between production strain and bacteria, the stability of the yeast strain and the recirculation of process water streams after the separation.
Monitoring Growth of Microorganisms using the Methods of Mass‐Energy Balance and Utilization of Computer on Line with Fermenter in Real Time Processing (in Russian)
Authors: Minkevich I. G. , Lysenko I. G. , Kuvshinikov W. D. , Eroshin W. D.
Published: December 2004

The effective means of microbial culture monitoring is the measurement of low‐inertial parameters (respiration rate, rates of supply of alkali for pH maintenance and the limiting substrate) and utilization of computer on line with fermenter for recalculation of these rates into the instant values of mass and energy cell yields, specific rates of cell growth and substrate and oxygen consumption, using the method of mass‐energy balance. In this paper, the equations of mass‐energy balance are presented both in general form and in the form of numerical algorythms for computer programming.

The installation for automation of microbial cultivation experiment is described. Experimental data are presented which indicate the effectiveness of the method of indirect measurement of cell biomass yield and specific rates of physiological processes.
Fluorometric device for direct measuring of culture fluorescence within fermenters
Authors: Däberitz H. , Schmidt A.
Published: December 2004

A fluorometric device for direct measuring of culture fluorescence within the fermenter is described. The calibration by quinine sulfate as well as the response to a step increase of the input is presented.
Vergleich von Messungen des kLa‐Wertes nach der stationären und der dynamischen Methode bei der Fermentation von L‐Lysin und Turimycin
Authors: Möckel H‐O.
Published: December 2004

The calculation and scale‐up of fermentation processes need kLa as one of the most important engineering data. There are two methods to determine kLa depending on power input, aeration rate and the properties of the fermentation broth: static with a balance between air supply and exit, dynamic gassing out with following the changes of dissolved oxygen concentration during periods of air off and a following air on.

Within early intervals of fermentation time the data from both methods agree well, while for later time intervals the dynamic method always gives much lower values for kLa than static. The only explanations for this phenomenon are quick changes in the oxygen metabolism or an enzymatic storage of oxygen. For both gassing out and saturation period it is possible to calculate the same absolute amounts of this additional oxygen.
Lysis and “cryptic” growth in wastewater and sludge treatment processes
Authors: Hamer G.
Published: December 2004

The primary objectives in biological wastewater and sludge treatment processes are to procedure a minimum quantity of solid, stable residues and a maximum quantity of carbon dioxide from the organisms present in the process feeds. As far as minimizing solids production in activated sludge type processes is concerned, endogenous activity in the recycled biomass is usually considered to be the most important mechanism. However, increased understanding of the growth characteristics of mixed microbial cultures suggests that lysis and “cryptic” growth are probably dominant mechanisms. For pathogen destruction in treatment processes, death and subsequent lysis of pathogens are clearly events that must be promoted.

Here, the kinetics for death, lysis and “cryptic” growth in aerobic wastewater treatment and aerobic sludge stabilization processes are examined.
Biodegradability of swine effluents I. Oxygen consumption
Authors: Oliveira J. S. , Costa M. L. , Rodrigues A. , Menezes J. G. A. , Pereira A. M. L.
Published: December 2004

Positive and negative effects of dilution of raw effluents from swine breeding are discussed, as to the treatability of those waste waters. Its effects on oxygen consumption and on the variation of inhibitory actions possibly observed, are studied and quantified. Using BRADENDER and VANDEPUTTE techniques based on peptone degradation, and determining PHELPS'S equation parameters for different consumption curves observed, the advantages of dilution versus treatment of raw effluents is studied.
Stereoselective hydrolysis of optically active isomeric isopulegyl acetates by rhodotorula mucilaginosa and bacillus sp.
Authors: Monkiewicz A. , Góra J.
Published: December 2004

A method for isolation of optically pure l‐isopulegol from a mixture of its optically active isomers using the microorganisms Rhodotorula mucilaginosa and Bacillus sp. is described.

Microorganisms hydrolyzed l‐isopulegyl acetate (26–40%) and in a small degree d‐isopulegol acetate whereas the d‐neoisopulegol acetate remained non‐hydrolyzed.

The optical purity of the chromatographie pure l‐isopulegol was 97.6%.
Wirkung von Ölen und Fettsäuren auf Wachstum und Enzymbildung bei Thermoactinomyces vulgaris. IV. Einfluß von Art und Menge des Öles sowie des Zeitpunktes der Ölzugabe
Authors: Leuchtenberger A. , Ruttloff H.
Published: December 2004

The effect of different quantities and kinds of vegetable and animal oils and the importance of the time of the oil addition on growth and protease synthesis by T. vulgaris was investigated. The used oils stimulate the protease production if they are added in a suitable concentration. However, the stimulation effect of each oil is different. Culture inoculation with spores gives the best results, when oil was added to the medium 1 up to 2 hours after beginning of the fermentation. The enzyme activity is equal to or lower than the control, when the oil addition was carried out before or 3 hours after starting the fermentation.
The influence of carbon catabolism on the auxiliary substrate effect, Paper given at the Reinhardsbrunn Symposium “Phyusiology of Microbial Growth and Differentiation”, May 20–26, 1984
Authors: Babel W. , Müller R. H.
Published: December 2004

Although the carbon/energy ratios of heterotrophic substrates for microbial growth are different this is not reflected in biomass. Nevertheless the macromolecular composition of cells may vary in dependence on growth conditions this does hardly influence the elementary composition and the growth yield. The energy requirement for synthesis of biomass starting from a central precursor, e.g. phosphoglycerate, can be assumed to be constant, hence any differences in carbon conversion efficiency must be attributed to carbon catabolism up to this precursor. This sequence determines if and to what extent an auxiliary substrate effect is possible. However, one has also to consider changes of the P/O ratio due to simultaneous utilization of substratesd which may account for the increase in growth yield with Hansenula polymorpha growing on a methanol/glucose mixture.
Zur Kinetik des Wachstums und der Speicherung von Poly‐D(−)‐3‐hydroxybuttersäure bei Alcaligenes latus
Authors: Braunegg G. , Bogensberger B.
Published: December 2004

Alcaligenes latus strain DSM 1123 has been tested for the production of Poly‐D(−3)‐3‐hydroxybutyric acid using sucrose as the only carton source. The strain is capable of accumulating the polymer associated to the growth very fast and lup to high concentrations in the biomass. Alcaligenes lotus seems to be very interesting for the production of Poly‐D(−)‐3‐hydroxybutyrate in a cheaper and easier way as with other organisms discussed for the biotechnological process in the past.
Biotechnology: Health care, agriculture, industry, environment
Authors: Sikyta B. , Pavlasová E. , Stejskalová E.
Published: December 2004

New developments in different branches of biotechnology are discussed. The production of peptide hormones, new interferons and other lymphokines by the microbial and cell cultures, and new enzyme inhibitors of microbial origin are the most important for health care and pharmacy. The main direction in research in the agriculture represents the development of the new, very effective methods of nitrogen fixation and the production of animal growth hormones by genemanipulated microorganisms. One of the most important field of application of biotechnology is the chemical industry, c.f. microbial production of polymers and biotransformation of compounds previously produced by chemical methods (acrylamide, adipic acid, naphtalen conversion, etc.). Several novel methods of degradation of the cellulosic materials are mentioned and exploitation of biotechnology in environmental protection is also discussed.
Purification and Characterization of two Extracellular β‐Glucosidases from Trichoderma viride ITCC 1433
Authors: Wilhelm M. , Sahm H.
Published: December 2004

T. viride ITCC 1433 synthesizes a two component system for the hydrolysis of cellobiose and cellooligodextrins. 80% of the total activity are solubilized during growth. The large protein (A), mol. weight 98 000 d, is glycosylated and slightly acidic (pH = 6.1). The smaller protein (B), mol. weight 70 000 d, is unglycosylated and neutral (pH = 7.2). Both proteins form a two‐step system where β‐glucosidase A is active at low substrate concentrations (KM = 2.3 × 10−4 M cellobiose) while β‐glucosidase B covers the range of 10‐fold higher cellobiose concentrations (KM = 1.8 × 10−3 M). The enzymes are fairly stable with a residual activity of 70% at 50°C after 24 h.
Evaluation of nigerian millet (pennisetum typhoideum) as a raw material for beer production
Authors: Iwuagwu Y. O. U. , Izuagbe Y. S.
Published: December 2004

Millet (Pennisetum typhoideum) its malt and wort were evaluated to ascertain the suitability of the grain for beer production. Thousand grain weight was 8.03 g while foreign material and broken cernels represented 3.23%. Germination energy, germination capacity and moisture content of the grain were 75.67, 92.33 and 10.43%, respectively, while the carbohydrate, total nitrogen and protein contents were 53.88, 1.34 and 8.40%, respectively. Millet malt had a moisture content of 5.03% while its carbohydrate, total nitrogen, protein content and malting loss were 48.47, 1.87, 11.7 and 8.3%. pH and specific gravity of the worth were 5.70 and 1.5927, respectively; its protein content was negligible while % titratable acidity was 1.35. The low nitrogen and protein contents of the grain as well as the low malting loss make millet an attractive alternative cereal for beer production in Nigeria.