bluuebunny/crossref_metadata_2025 huggingface dataset:
The search for a cometary outbursts mechanism: a comparison of various theories
Authors: Gronkowski P.
Published: February 2007

In the paper the potential sources of energy of cometary outbursts have been reviewed. Considerations focus on four probable sources of the outbursts' energy. These are the polymerization of hydrogen cyanide HCN, impacts with the meteoroids, destruction of cometary grains in the field of strong solar wind and the transformation of amorphous water Ice into the crystalline one. The values of released energy and jumps of cometary brightness caused by these mechanisms have been discussed. A modern approach to the problem of the thermodynamical evolution of the comet nucleus which includes amorphous water ice is considered as the starting point in the discussion presented in the paper. The main characteristics of an outburst of a hypothetical comet belonging to the Jupiter family comet are calculated. The obtained results are in a good agreement with the characteristics observed during the real outbursts of comets. The main conclusion of this paper confirms a general presumption that the cometary outbursts can have different causes. However, the hypothesis concerning the amorphous water ice transformation appears to be the most probable one. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Applying the Generalized Partitioning Principle to Control the Generalized Familywise Error Rate
Authors: Xu Haiyan , Hsu Jason C.
Published: February 2007

In multiple testing, strong control of the familywise error rate (FWER) may be unnecessarily stringent in some situations such as bioinformatic studies. An alternative approach, discussed by Hommel and Hoffmann (1988) and Lehmann and Romano (2005), is to control the generalized familywise error rate (gFWER), the probability of incorrectly rejecting more than m hypotheses. This article presents the generalized Partitioning Principle as a systematic technique of constructing gFWER‐controlling tests that can take the joint distribution of test statistics into account. The paper is structured as follows. We first review classical partitioning principle, indicating its conditioning nature. Then the generalized partitioning principle is introduced, with a set of sufficient conditions that allows it to be executed as a computationally more feasible step‐down test. Finally, we show the importance of having some knowledge of the distribution of the observations in multiple testing. In particular, we show that step‐down permutation tests require an assumption on the joint distribution of the observations in order to control the familywise error rate. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Test for Increasing Convex Order in Multivariate Response
Authors: Feng Yanqin , Wang Jinde
Published: February 2007

Trend test based on cross‐classified data in dose‐response has been a central problem in medicine. Most of existing test methods are known to only fit to binary response variables. However, the approaches for binary response tables may suffer from the lack of a clear choice for dichotomization. For multivariate response with ordered categories, some studies have been done for simple stochastic order, likelihood ratio order and so on. However, methods of statistical inference on increasing convex order for more than two multinomial populations have not been fully developed. For testing the increasing convex order alternative, this article provides a model‐free test method which can be used in the case of two‐way tables and stratified data. Two real examples will be used to illustrate how to apply our test method. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient bioremediation of total organic carbon (TOC) in integrated aquaculture system by marine sponge Hymeniacidon perleve
Authors: Fu Wantao , Wu Yichun , Sun Liming , Zhang Wei
Published: February 2007

The aim of this study is to investigate the potential of using marine sponge Hymeniacidon perleve to remove total organic carbon (TOC) in integrated aquaculture ecosystems. In sterilized natural seawater (SNSW) with different concentrations of TOC, H. perleve removed approximately 44–61% TOC during 24 h, with retention rates of ca. 0.19–1.06 mg/h ·g‐fresh sponge, however no particulate selectivity was observed. The highest initial TOC concentration, in which about 2.7 g fresh sponges could remove TOC effectively in 0.5‐L SNSW, is 214.3–256.9 mg/L. The highest capacity of TOC removal and clearance rate (CR) by H. perleve is ca. 25.50 mg‐TOC/g‐fresh sponge and 7.64 mL/h · g‐fresh sponge within 24 h, respectively. Until reaching the highest TOC removal capacity, the TOC removal capacity and clearance rate of H. perleve increased with initial TOC concentration, and dropped dramatically thereafter. After reaching the highest removal capacity, H. perleve could only remove relatively lower TOC concentration in seawater in subsequent run. The TOC removal kinetics in SNSW by H. perleve fitted very well with a S‐shaped curve and a Logistic model equation (R2 = 0.999). In different volumes of SNSW with a fixed initial TOC concentration, the weight/volume ratio of sponge biomass and SFNSW was optimized at 1.46 g‐fresh sponge/1‐L SNSW to achieve the maximum TOC removal. When co‐cultured with marine fish Fugu rubripes for 15 days, H. perleve removed TOC excreted by F. rubripes with similar retention rates of ca. 0.15 mg/h · g‐fresh sponge, and the sponge biomass increased by 22.8%. Biotechnol. Bioneg. 2007;97: 1387–1397. © 2007 Wiley Periodicals, Inc.
Improving AAV vector yield in insect cells by modulating the temperature after infection
Authors: Aucoin Marc G. , Perrier Michel , Kamen Amine A.
Published: February 2007

Vectors based on adeno‐associated viruses (AAV) are sought for therapeutic gene delivery because of their ability to transduce a variety of tissues with no significant immunological response. Production using the baculovirus expression vector (BEV)/insect cell system has the potential to meet the needs for pre‐clinical and clinical trials. In this co‐infection system, three baculoviruses are used to produce the AAV vector. A strategy aimed at increasing encapsidation/maturation of the viral vector involved varying the temperature over the course of the process. Cultures were subjected to temperature changes at various times pre‐ and post‐infection (up to 24 h post‐infection). It was found that raising the culture temperature to 30°C at the time of infection nearly tripled the infectious titer. In fact, increasing the temperature to 30°C at any time in the process investigated resulted in an increase in titer. Also, raising the culture to 33°C or lowering the temperature to 24° or 21°C resulted in lower titers. The rise in infectious titer was also confirmed by an increase in DNase resistant particles (DRPs). Varying the temperature, however, did not affect the total amount of capsids significantly. Therefore increasing the culture temperature resulted in better encapsidation as determined by the ratio of capsids to DRPs to infectious particles. It is believed that an increase in early proteins and possibly a quicker cascade of baculovirus infection events resulted in this increased packaging efficiency. Biotechnol. Bioeng. 2007;97:1501–1509. © 2007 Wiley Periodicals, Inc.
Electricity generation from cellulose by rumen microorganisms in microbial fuel cells
Authors: Rismani‐Yazdi Hamid , Christy Ann D. , Dehority Burk A. , Morrison Mark , Yu Zhongtang , Tuovinen Olli H.
Published: February 2007

In microbial fuel cells (MFCs) bacteria generate electricity by mediating the oxidation of organic compounds and transferring the resulting electrons to an anode electrode. The objective of this study was to test the possibility of generating electricity with rumen microorganisms as biocatalysts and cellulose as the electron donor in two‐compartment MFCs. The anode and cathode chambers were separated by a proton exchange membrane and graphite plates were used as electrodes. The medium in the anode chamber was inoculated with rumen microorganisms, and the catholyte in the cathode compartment was ferricyanide solution. Maximum power density reached 55 mW/m2 (1.5 mA, 313 mV) with cellulose as the electron donor. Cellulose hydrolysis and electrode reduction were shown to support the production of current. The electrical current was sustained for over 2 months with periodic cellulose addition. Clarified rumen fluid and a soluble carbohydrate mixture, serving as the electron donors, could also sustain power output. Denaturing gradient gel electrophoresis (DGGE) of PCR amplified 16S rRNA genes revealed that the microbial communities differed when different substrates were used in the MFCs. The anode‐attached and the suspended consortia were shown to be different within the same MFC. Cloning and sequencing analysis of 16S rRNA genes indicated that the most predominant bacteria in the anode‐attached consortia were related to Clostridium spp., while Comamonas spp. abounded in the suspended consortia. The results demonstrated that electricity can be generated from cellulose by exploiting rumen microorganisms as biocatalysts, but both technical and biological optimization is needed to maximize power output. Biotechnol. Bioeng. 2007;97: 1398–1407. © 2007 Wiley Periodicals, Inc.
An Experimental and Computational Study on Intramolecular Charge Transfer: A Tetrathiafulvalene‐Fused Dipyridophenazine Molecule
Authors: Jia Chunyang , Liu Shi‐Xia , Tanner Christian , Leiggener Claudia , Neels Antonia , Sanguinet Lionel , Levillain Eric , Leutwyler Samuel , Hauser Andreas , Decurtins Silvio
Published: February 2007

To study the electronic interactions in donor–acceptor (D–A) ensembles, D and A fragments are coupled in a single molecule. Specifically, a tetrathiafulvalene (TTF)‐fused dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz) compound having inherent redox centers has been synthesized and structurally characterized. Its electronic absorption, fluorescence emission, photoinduced intramolecular charge transfer, and electrochemical behavior have been investigated. The observed electronic properties are explained on the basis of density functional theory.
The Phenalenyl Motif: A Magnetic Chameleon
Authors: Cyrański Michał K. , Havenith Remco W. A. , Dobrowolski Michał A. , Gray Benjamin R. , Krygowski Tadeusz M. , Fowler Patrick W. , Jenneskens Leonardus W.
Published: February 2007

The 12π cation (3) and 14π anion (4) derived from the phenalenyl radical (2) support diatropic (“aromatic”) perimeter ring currents, but isoelectronic replacement of the central atom by either boron (5) or nitrogen (6) leads to paratropic (“antiaromatic”) current; the ipsocentric approach to molecular magnetic response accounts for all four patterns in terms of competition between translationally and rotationally allowed virtual π–π* excitations.
Growth and characterization of non‐linear optical crystal ZnCd(SCN)4
Authors: Joseph G. P. , Rajarajan K. , Vimalan M. , Thomas P. C. , Madhavan J. , Ravi Kumar S. M. , Gulam Mohamed M. , Mani G. , Sagayaraj P.
Published: February 2007

Single crystals of ZCTC with dimension up to 5x2x3mm3 were grown from aqueous solution by slow solvent evaporation method and the grown crystals were confirmed by single XRD and CHN analysis. The SHG efficiency of ZCTC was evaluated using Kurtz Perry technique. Its efficiency was found to be nearly 12 times that of urea when studied with the fundamental wavelength of 1064 nm. The mechanical properties of the grown crystal have been investigated by Vickers microhardness testing. The thermal parameters such as the thermal diffusivity (α), thermal effusivity (e), thermal conductivity (k) and heat capacity (cp) of ZCTC were measured by an improved photopyroelectric (PPE) technique and the results were discussed. The TG/DTG studies reveal that the decomposition of the sample begins around 350°C. The photoconducting nature of ZCTC has also been investigated and reported. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of metallic substitution on the physical properties of manganese mercury thiyocyanate crystals
Authors: Joseph G. P. , Korah I. , Raja Rajan K. , Thomas P. C. , Vimalan M. , Madhavan J. , Sagayaraj P.
Published: February 2007

Good optical grade single crystals of pure, Cd2+ and Mg2+ doped Manganese Mercury Thiyocyanate (MMTC) crystals are grown by slow solvent evaporation technique at room temperature. Single crystal XRD studies reveal that the incorporation of metallic dopants has not changed the structure of the parent crystal. The SHG efficiencies of the pure and doped samples of MMTC are measured by Kurtz Perry powder method and the results are compared with urea. It is evident from microhardness study that the presence of dopants has increased the mechanical strength of MMTC crystal. The TG/DTG studies confirm that the thermal decomposition temperatures of pure (353°C), Mg2+ doped (363°C) and Cd2+ doped (365°C) MMTC are relatively high when compared to other NLO crystals of the same family. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Progress in Spectroscopic Diagnostics of Barrier Discharges
Authors: Kozlov K. V. , Wagner H.‐E.
Published: February 2007

Systematic study of barrier discharges (BDs) using cross‐correlation spectroscopy (CCS) has been conducted since 2000 by two research teams at the universities in Moscow and in Greifswald. From the beginning, the investigations were focused on the application of the CCS diagnostics to the BDs in air and in N2/O2 mixtures. Further progress in the research field being considered was aimed on the one hand, at the improvement of the measurement technique and development of the data processing procedures, and on the other hand, at using different working gases and gas mixtures. In this paper, the most interesting and important research results obtained in the course of two last years at both referred above universities using the CCS technique are reported. They correspond to three different subjects of investigation, namely an analysis of axial and radial structure of the microdischrge in air at ambient pressure, an influence of the composition of binary mixtures Ne/O2 upon the mechanism of the BD development, and spatio‐temporal structure of the BD in pure argon. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
“Tissue Processing” with Atmospheric Plasmas
Authors: Stoffels E.
Published: February 2007

This article surveys current applications of gas discharges in various medical procedures. Various designs of non‐equilibrium plasma sources are described, with special attention to cold plasma devices. In “tissue processing”, two approaches are distinguished: thermal processing, such as heat‐induced coagulation, desiccation, cutting and ablation, and non‐thermal processing, based on sub‐lethal plasma effects on living cells. The latter technique requires special low‐power sources, which operate at the body temperature. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Combination of a spinning disc confocal unit with frequency‐domain fluorescence lifetime imaging microscopy
Authors: van Munster E. B. , Goedhart J. , Kremers G. J. , Manders E. M. M. , Gadella T. W. J.
Published: February 2007

Background:

Wide‐field frequency‐domain fluorescence lifetime imaging microscopy (FLIM) is an established technique to determine fluorescence lifetimes. Disadvantage of wide‐field imaging is that measurements are compromised by out‐of‐focus blur. Conventional scanning confocal typically means long acquisition times and more photo bleaching. An alternative is spinning‐disc confocal whereby samples are scanned simultaneously by thousands of pinholes, resulting in a virtually instantaneous image with more than tenfold reduced photo bleaching.

Methods:

A spinning disc unit was integrated into an existing FLIM system. Measurements were made of fluorescent beads with a lifetime of 2.2 ns against a 5.3 ns fluorescent background outside the focal plane. In addition, living HeLa cells were imaged with different lifetimes in the cytosol and the plasma membrane.

Results:

In spinning‐disc mode, a lifetime of the beads of 2.8 ns was measured, whereas in wide field a lifetime of 4.1 ns was measured. Lifetime contrast within living HeLa cells could be resolved with the spinning‐disc unit, where this was impossible in wide field.

Conclusions:

Integration of a spinning‐disc unit into a frequency‐domain FLIM instrument considerably reduces artifacts, while maintaining the advantages of wide field. For FLIM on objects with 3D lifetime structure, spinning‐disc is by far preferable over wide‐field measurements. © 2007 International Society for Analytical Cytology.
Identification and quantification of high fluorescence‐stained lymphocytes as antibody synthesizing/secreting cells using the automated routine hematology analyzer XE‐2100
Authors: Linssen J. , Jennissen V. , Hildmann J. , Reisinger E. , Schindler J. , Malchau G. , Nierhaus A. , Wielckens K.
Published: February 2007

Objectives:

The aim of this study was to classify and quantify the high fluorescence lymphocytes area (HFL‐count) from the SYSMEX XE‐2100 leucocyte differential channel as antibody‐synthesizing or ‐secreting cells (ASC, plasma cells or lymphoplasmacytoid cells) in reactive diseases. To unequivocally identify the HFL cells, all possibly eligible cell populations have been investigated: activated B‐lymphocytes, activated T‐lymphocytes, large granular lymphocytes (LGL), activated monocytes, and immature granulocytes.

Methods:

In total, 85 patients were analyzed on the XE‐2100 and compared with the automated image analysis system Cellavision Diffmaster 96 based on artificial neural network and immunophenotyping method with the BD FACSCalibur™.

Results:

Reproducibility tests for HFL demonstrated a mean coefficient of variation of 13.9% for very low results and 1.5% for high results. The linearity data showed a good correlation (R2 = 0.99) between expected and measured HFL. The comparison with possibly eligible cell populations showed no significant correlation between activated monocytes and immature granulocytes, with most immature granulocytes (promyelocyte I or II), natural killer cells or LGLs, activated T‐lymphocytes, and sub‐T‐lymphocytes populations. However, for activated B‐lymphocytes an excellent significant correlation with the peripheral blood smear, and the immunophenotyping method has been found with R2 = 0.900, P < 0.001 and R2 = 0.897, P < 0.001, respectively. The slope of 1.1 and intercept of minus 5 cells/μL of the regression equation between HFL‐count and ASC (smear) do indicate an excellent quantification of the HFL‐count, as well.

Conclusion:

The fully automated SYSMEX XE‐2100 HFL‐count identifies and quantifies the ASC cells (activated B‐lymphocytes) with high precision and reliability in patients without hematology system diseases, thus providing a potential screening and monitoring tool for any patient with suspected infection. Additional studies are required to comprehend in more detail the full clinical utility of an HFL (ASC) count as a potential diagnostic indicator of inflammation, infection, or sepsis. © 2007 International Society for Analytical Cytology
Reticulated platelet counts correlate with treatment response in patients with idiopathic thrombocytopenic purpura and help identify the complex causes of thrombocytopenia in patients after allogeneic hematopoietic stem cell transplantation
Authors: Thomas‐Kaskel Anna‐Katharina , Mattern Dominik , Köhler Gabriele , Finke Jürgen , Behringer Dirk
Published: February 2007

Background:

In thrombocytopenic conditions of unknown origin, quantification of reticulated platelets (RP) in the peripheral blood by flow cytometry has been shown to differentiate increased platelet (Plt) turnover from insufficient Plt production.

Methods:

We used a whole blood flow cytometry method combining thiazole orange and anti‐CD41a‐staining to assess RP in 71 healthy subjects, six with thrombocytopenic myelodysplastic syndrome (MDS), nine with liver cirrhosis, 14 patients with idiopathic thrombocytopenic purpura (ITP), and 12 patients who had undergone hematopoietic stem cell transplantation (HSCT).

Results:

Patients with MDS had normal, patients with liver cirrhosis had slightly elevated RP counts compared to healthy subjects. ITP patients had elevated RP counts, and RP >15% were associated with treatment response (P = 0.015). In 7/10 patients after HSCT, an increase of RP preceded Plt recovery, whereas in patients with secondary thrombocytopenia after normal regeneration, the assessment of RP allowed the differentiation between conditions with high Plt turnover, such as GvHD and microangiopathy, indicated by high RP counts, and graft failure, indicated by low RP counts.

Conclusions:

Our data provide the rationale for prospective studies on the diagnostic and prognostic value of RP counts in larger patient populations with ITP and after HSCT. © 2007 Clinical Cytometry Society
Accurate assessment of cell count and viability with a flow cytometer
Authors: Shenkin Mark , Babu Ramesh , Maiese Russell
Published: February 2007

Background:

In this study we developed a method to measure cell concentration and viability in specimens received in flow cytometry and cytogenetics laboratories.

Methods:

Specimens are stained with a vital fluorescent dye, SYTO13, the cell impermeant viability dye, 7‐AAD, and a leukocyte marker, CD45. After the addition of an internal calibrator microsphere, FLOW‐COUNT™, the flow cytometer is capable of measuring the viability of nucleated cells, giving a general assessment of leukocyte populations and measuring their concentration.

Results:

An accurate assessment of specimen quality is an important parameter when performing flow cytometric and cytogenetic leukemia/lymphoma assessment. High quality specimen is desired to avoid the pitfalls of non‐specific staining and limited cellularity/viability.

Conclusions:

Use of a cell count and viability measurement prior to leukemia and lymphoma assessment by flow cytometry and cytogenetics helps to increase the rate of successful immunophenotypic and cytogenetic analysis. © 2007 Clinical Cytometry Society
Time‐dependent postsynaptic AMPA GluR1 receptor recruitment in the cingulate synaptic potentiation
Authors: Toyoda Hiroki , Wu Long‐Jun , Zhao Ming‐Gao , Xu Hui , Zhuo Min
Published: February 2007

The anterior cingulate cortex (ACC) is critical for brain functions including learning, memory, fear and pain. Long‐term synaptic potentiation (LTP), a cellular model for learning and memory, has been reported in the ACC neurons. Unlike LTP in the hippocampus and amygdala, two key structures for memory and fear, little is known about the synaptic mechanism for the expression of LTP in the ACC. Here we use whole‐cell patch clamp recordings to demonstrate that cingulate LTP requires the functional recruitment of GluR1 AMPA receptors; and such events are rapid and completed within 5–10 min after LTP induction. Our results demonstrate that the GluR1 subunit is essential for synaptic plasticity in the ACC and may play critical roles under physiological and pathological conditions. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
The notion of ‘phonology’ in dyslexia research: cognitivism—and beyond
Authors: Uppstad Per Henning , Tønnessen Finn Egil
Published: February 2007

Phonology has been a central concept in the scientific study of dyslexia over the past decades. Despite its central position, however, it is a concept with no precise definition or status. The present article investigates the notion of ‘phonology’ in the tradition of cognitive psychology. An attempt is made to characterize the basic assumptions of the phonological approach to dyslexia and to evaluate these assumptions on the basis of commonly accepted standards of empirical science. First, the core assumptions of phonological awareness are outlined and discussed. Second, the position of Paula Tallal is presented and discussed in order to shed light on an attempt to stretch the cognitive‐psychological notion of ‘phonology’ towards auditory and perceptual aspects. Both the core assumptions and Tallal's position are rejected as unfortunate, albeit for different reasons. Third, the outcome of this discussion is a search for what is referred to as a ‘vulnerable theory’ within this field. The present article claims that phonological descriptions must be based on observable linguistic behaviour, so that hypotheses can be falsified by data. Consequently, definitions of ‘dyslexia’ must be based on symptoms; causal aspects should not be included. In fact, we claim that causal aspects, such as ‘phonological deficit’, both exclude other causal hypotheses and lead to circular reasoning. If we are to use terms such as ‘phonology’ and ‘phoneme’ in dyslexia research, we must have more precise operationalizations of them. Copyright © 2007 John Wiley & Sons, Ltd.
Secondary immunisation with high‐dose heterologous peptide leads to CD8 T cell populations with reduced functional avidity
Authors: Narayan Sharmal , Choyce Allison , Fernando Germain J. P. , Leggatt Graham R.
Published: February 2007

Expansion of high‐ or low‐avidity CD8 T cells in vitro inversely correlates with the concentration of peptide ligand present during culture. In contrast, the selective enrichment of high‐ or low‐avidity T cell populations in vivo using peptide immunisation is not well documented. In our study, a single immunisation with different doses of wild‐type peptide or a variant peptide able to stimulate CTL responses cross‐reactive with wild‐type peptide failed to shift the average avidity of the responding CD8 T cell population specific to either peptide. However, in contrast to homologous prime‐boost immunisation, heterologous prime‐boost immunisation incorporating high doses of the second immunogen resulted in peptide‐specific CD8 T cell populations polarized toward a low average functional avidity. These data suggest that sequential exposure to structurally related viral peptides could impair rather than promote anti‐viral immunity by lowering the avidity of the responding CD8 T cell population. This study has implications for improving vaccine strategies against viruses and tumours and enhances our understanding of heterologous immunity during sequential viral infection.
CD38 cross‐linking enhances TLR‐induced B cell proliferation but decreases IgM plasma cell differentiation
Authors: Manjarrez‐Orduño Nataly , Moreno‐García Miguel E. , Fink Katja , Santos‐Argumedo Leopoldo
Published: February 2007

It is becoming increasingly clear that the regulation of proliferation and differentiation of B cells to plasma cells involves the integration of a variety of intracellular signals provided by receptors of both the adaptive and innate immune system. The cross‐linking of the surface molecule CD38 induces calcium mobilization, protein phosphorylation and NF‐κB translocation into the nucleus, ultimately leading to proliferation and isotype switching toward IgG1. Here we describe (a) the effect on B cell activation of stimulating through both CD38 and Toll‐like receptors 4, 7 and 9; and (b) that CD38 cross‐linking increases the number of proliferating cells and the rate of proliferation in LPS‐stimulated B cells by a Bruton's tyrosine kinase‐ and protein kinase C‐dependent mechanism. In contrast, CD38 cross‐linking reduces the number of cells committed to IgM plasma cell differentiation as measured by the number of CD138+ cells, antibody secretion, and the expression of PAX5, Bcl6 and Blimp‐1. Since a putative ligand for CD38 is expressed by germinal center follicular dendritic cells, and CD38 expression is down‐regulated in germinal center B cells, we speculate that CD38 might participate in the outcome of post‐germinal center antibody responses.
A Bis(di‐n‐butyltin)–Quinone Derivative as a Simultaneous Chemo‐ and Bioactive Corrosion Inhibitor
Authors: Barba Victor , Vega Edgar , Höpfl Herbert , Zamudio‐Rivera Luis S. , Domínguez‐Aguilar Marco A. , George‐Tellez Rocío , Godínez‐Salomon Fernando , Hallen‐Lopez José M. , Beltran Hiram I.
Published: February 2007

The bis(di‐n‐butyltin) derivative of 2,5‐bis(2‐hydroxyethylamino)‐1,4‐benzoquinone was synthesized and characterized by common spectroscopic techniques. In solution, discrete molecules with pentacoordinate tin atoms were observed, whereas the X‐ray diffraction analysis of the solid‐state structure revealed polymeric chains that were due to intermolecular Sn···O bonds. In vitro tests demonstrated that the tin compound displays bactericidal activity against a wide range of aerobic and anaerobic bacteria. Acute toxicity tests indicated that the di‐n‐butyltin compound has a relatively low toxicity level. The corrosion inhibition efficiency of the ligand and the tin compound were evaluated by polarization scans of mild steel samples that had been exposed to a sour brine environment. The tin–quinone compound showed good inhibition efficiency (about 75 %) at relatively low concentrations (25–50 ppm) and at different testing times (0.25–20 h).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
γ‐Aminoadamantanecarboxylic Acids Through Direct C–H Bond Amidations
Authors: Wanka Lukas , Cabrele Chiara , Vanejews Maksims , Schreiner Peter R.
Published: February 2007

Utilizing bromine‐free, direct C–H bond amidations we have synthesized a large variety of adamantane amides. Depending on the precursors used these amides directly yield pharmaceutically active aminoadamantanes or γ‐aminoadamantanecarboxylic acids after hydrolytic cleavage. Theserigid analogues of γ‐aminobutyric acid (GABA) were protected at the C‐ and N‐termini and we synthesized a number of peptides incorporating γ‐aminoadamantanecarboxylicacids in solution as well as via solid phase peptide synthesis. These peptides are promising scaffolds for applications in medicinal chemistry as well as in organocatalysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
3D‐Ensembles of Gold Nanowires: Preparation, Characterization and Electroanalytical Peculiarities
Authors: De Leo Manuela , Kuhn Alexander , Ugo Paolo
Published: February 2007

Nanoelectrode ensembles (NEEs) of gold nanodisks, prepared by electroless template deposition of gold within the pores of track‐etched polycarbonate membranes, are treated with oxygen plasma or with solvent mixtures in order to achieve controlled etching of part of the polycarbonate of the template. This causes the structure of the final ensemble to change from a 2‐D flat structure into a 3‐D one. The cyclic voltammetric (CV) behavior of redox probes at the 3D‐NEEs is examined and compared with the behavior observed at 2D‐NEEs. Finally, 3D‐NEEs are examined in order to test possible applications for the development of mediated sensors.
A Suggestion of Electrochemical Biosensor for Study of Platinum(II)‐DNA Interactions
Authors: Krizkova Sona , Adam Vojtech , Petrlova Jitka , Zitka Ondrej , Stejskal Karel , Zehnalek Josef , Sures Bernd , Trnkova Libuse , Beklova Miroslava , Kizek Rene
Published: February 2007

As a consequence of the employment of platinum based cytostatic drugs in tumor diseases treatment, it became necessary not only to detect them in biological samples but also to determine and study the Pt‐DNA adducts, which is highly important during investigation of resistance on antitumor treatment. Thus, the main objective of this work was to study the interactions between DNA and cisplatin. Primarily, we studied changes in electrochemical behavior of cisplatin in the presence of different concentrations of sodium chloride using differential pulse voltammetry. We found out that the highest signal of cisplatin was measured in 0.75 M NaCl with detection limit of 100 pM. The current accepted opinion about platinum based cytostatics mechanism of action is that the drugs induce their cytotoxic properties through binding to the nuclear DNA. That is why we followed by investigation of DNA interactions with cisplatin. For these purposes we have suggested a new biosensor, EDTA metallothionein modified hanging mercury drop electrode (EDTA MT biosensor) and used cyclic voltammetry as a comparative technique. The average concentration of the drug bound to DNA was estimated as 8.1 ng of cisplatin per 500 ng of DNA by EDTA MT biosensor. It follows from the results obtained that the suggested EDTA MT biosensor could be a new useful tool for investigation of interaction of DNA with cisplatin, because give a response only in the present of Pt(II)‐DNA adduct.
New Aspects of Microbial Nitrogen Transformations in the Context of Wastewater Treatment – A Review
Authors: Paredes D. , Kuschk P. , Mbwette T. S. A. , Stange F. , Müller R. A. , Köser H.
Published: February 2007

Over the past few years, new technologies for nitrogen removal have been developed mainly because of the increasing financial costs of the traditional wastewater treatment technologies. Newly discovered pathways, like the anaerobic oxidation of ammonium (ANAMMOX), and uses for nitrogen removal technologies are under discussion. Processes and technologies such as: Partial nitrification; Single reactor systems for High Ammonium Removal Over Nitrite (SHARON); Anammox; Aerobic/anoxic deammonification; Oxygen Limited Autotrophic Nitrification‐Denitrification (OLAND); Completely Autotrophic Nitrogen Removal Over Nitrite (CANON); wetland based systems, all have a high potential for nitrogen removal. However, the pathways of nitrogen transformation processes are very complex. An understanding of how various environmental factors affect these processes and a sound knowledge of existing, worldwide experience pertaining to these novel technologies are the key if the nitrogen removal rates are to be improved and success is to be realized in full‐scale applications. This review describes the present knowledge of the new treatment technologies for wastewater with high nitrogen loads. Special emphasis is given to the influence of environmental factors and the reactor configuration on the nitrogen transformation process and microbial activity.
Preliminary Study towards the Use of In‐situ Microscopy for the Online Analysis of Microcarrier Cultivations
Authors: Anton F. , Burzlaff A. , Kasper C. , Brückerhoff T. , Scheper T.
Published: February 2007

In order to apply newly developed non‐invasive in‐situ microscope systems for the monitoring of microcarrier‐based cultivations, appropriate image analysis systems must be available. Thus a simple, but effective greyscale distribution scan algorithm was tested for the evaluation of images generated by either a standard phase‐contrast microscope or an in‐situ microscope. The images were analyzed according to their greyscale pattern in order to examine whether the greyscale distribution is a possibility to gain information about the covering ratio.

The mouse fibroblast cell line (NIH–3T3) was grown on different microcarrier spheres. At first, different microcarriers were tested with respect to their suitability for microscopic observation. In a second part, the phase‐contrast pictures and in‐situ microscope pictures of the microcarrier were separately analyzed using the histogram function of CorelPhotopaint, which analyzes the greyscale distribution within the chosen area. Due to the low optical density of the polydextrin matrix, the images of Cytodex 1 microcarriers proved to be an ideal model for the image analysis. Significant differences in the greyscale distribution of this microcarrier without cells and with increased cell density were observed. Therefore a relationship between the cell density on the microcarriers and the greyscale pattern can be assumed. After automating this image analysis and calibrating the cell number/greyscale pattern relationship, it should be possible to analyze the plating efficiency/covering ratio on the microcarrier online by in‐situ microscopy.
The Dow Stretford chemical recovery process
Authors: Alan Hammond C.
Published: February 2007

The Dow patented Stretford Chemical Recovery Process reclaims the two key chemicals while purging undesirable by‐products from Stretford gas sweetening plants. Recovery of these chemicals can reduce costs in terms of chemical loss and solution disposal. The process involves filtration, charcoal adsorption and ion exchange.
Use of electrochemical iron generation for removing heavy metals from contaminated groundwater
Authors: Brewster M. D. , Passmore R. J.
Published: February 2007

This paper utilizes data from two pilot studies conducted at Superfund Sites to discuss the electrochemical iron addition process developed by Andco Environmental Processes, Inc. Electrical current and steel electrodes were used to put ferrous and hydroxyl ions into solution. Once added, the chemistry was properly manipulated to provide coprecipitation and adsorption conditions capable of simultaneously removing a wide variety of heavy metals. The goals of the two projects were distinctly different. At the first site, conversion of ferrous ions to the ferric state resulted in thorough reduction of hexavalent chromium to trivalent chromium. Observations and results from this study are used to discuss system design, sludge production, and operating costs. At the second location, high concentrations of many metals required removal. The presence of arsenic necessitated chemically induced oxidation. Hydrogen peroxide was introduced to convert Fe+2 to Fe+3 and arsenite to arsenate. By efficiently shifting the equilibrium state and adjusting pH to create conditions for maximum anion adsorption, an arsenic removal efficiency of over 99.8 percent was obtained. Proper process application resulted in simultaneous removal of aluminum, arsenic, cadmium, chromium, lead, mercury, nickel, selenium, thallium, and zinc. Also, when necessary treatment conditions were provided and maintained, metals removal by three major mechanisms resulted in iron matrices that passed regulatory levels listed in conjunction with the Toxicity Characteristic Leaching Procedures (TCLP).
Weathering of sandstone by the combined action of frost and salt
Authors: Williams R. B. G. , Robinson D. A.
Published: February 2007

Preliminary results from a continuing series of laboratory experiments designed to examine the combined effects of salt and frost weathering indicate that some salts greatly enhance the breakdown of rocks by frost. Samples of Ardingly Sandstone from southeast England were soaked in saturated solutions of sodium chloride or sodium sulphate and subjected to alternating cycles of freezing and thawing. Rapid disintegration of the sandstone occurred within twenty cycles, in each of the salt solutions. In contrast, samples subjected to freezing and thawing in deionized water suffered very little damage unless they were saturated under vacuum.

When samples were subjected to twenty cycles of wetting and drying at temperatures above 0°C, those soaked in deionised water or sodium chloride suffered no appreciable damage but those soaked in sodium sulphate rapidly disintegrated.

Tentative explanations of these results are offered. The enhancement of frost weathering by salt appears to have been overlooked by many writers yet it is likely to be an important geomorphological process in those areas of mid and high latitudes where rocks are saturated with sodium salts.
Rapid honeycomb weathering (tafoni formation) in greywacke, S.E. AUSTRALIA
Authors: Gill Edmund D.
Published: February 2007

The development of honeycomb weathering on seawalls of non‐marine Lower Cretaceous greywacke built in 1943 and 1949 shows that under certain conditions this type of tafoni is a significant factor in the retrogradation of rocky coasts.
Micro‐topographic change on calcarenites, grand Cayman Island, West Indies
Authors: Spencer T.
Published: February 2007

Changes in micro‐topography, as a result of varying erosion rates, have been monitored on a calcarenite ridge on Grand Cayman Island, West Indies, using a traversing model of the micro‐erosion meter. Erosion takes place through the solution of a calcitic cement and ‘solutional disintegration’ results in a rapid change of micro‐relief. Where a protective crust is present, surface lowering is slower and also more uniform; thus the original relative relief is maintained.
A test of granulometric control of desert dune geometry
Authors: Wasson R. J. , Hyde R.
Published: February 2007

I. G. Wilson's hypothesis of coarse‐tail grain‐size control of dune spacing was derived from three dunefields in the Sahara and, although it was supplemented by measurements of spacing from other parts of the world, the grain‐size data come only from North Africa. In this paper the hypothesis is tested in the Australian dunefields. Australian dunes do not form separate categories on a P20/s (twentieth percentile/spacing) plot and, when placed on Wilson's diagram, the Australian data form a continuum between dunes and draas. Ripples maintain their identity, suggesting that the average saltation length of sand controls ripple wavelength while dunes and Wilson's draas are formed by secondary flow of some kind. In Australia the spread of data on the P20/s diagram indicates that grain‐size is not the prime control on s. Data from Australia and the Sahara indicate that direct linear relationships between s and h (dune spacing and height means respectively for blocks of dunes) occur but they have different slopes in different areas. These differences possibly reflect variations in vegetation and substrate as well as differences in wind regime. The separation of dunes from draas in the Sahara reflects the greater role of grain‐size in an area where coarse grains frequently occur in dune crests. The relative paucity of coarse grains in Australian dune crests may reflect the fine‐grained alluvium from which the dunes are derived. These differences may be ascribed to differing topography in Australia and the Sahara.
Accretion rates on some debris slopes in the Mt. Rae area, Canadian Rocky Mountains
Authors: Gardner James S.
Published: February 2007

Accretion of debris was monitored on six slopes in the Mt. Rae area of the Canadian Rocky Mountains for the period 1975–1982. Monitoring was accomplished by measuring annually the accumulated debris on fabric mats which were placed on the long profile of the slopes. Annual rates of accretion were extremely variable between points on the same slope, between slopes, and between years. The data do not show a systematic decrease in accretion downslope but indicate that an absence of accretion is more likely on the lower half of the slopes. In general, annual rates are comparable to previously published values from the Rockies and the maximum rates of 30 to 40 mm per year are comparable to those from Karkevagge in Scandinavia. Extremely high rates of accretion were all related to extreme events such as debris flows or full depth snow avalanches. The variation in accretion rates is not explained by single environmental factors such as lithology and slope exposure.
The impact of afforestation on stream bank erosion and channel form
Authors: Murgatroyd A. L. , Ternan J. L.
Published: February 2007

Modification of the land use of a small catchment through coniferous afforestation is shown to have influenced stream bank erosion and channel form. Field mapping and erosion pin measurements over a 19‐month period provides evidence of more active bank erosion along forested channel reaches than along non‐forested. Extrapolation of downstream increases in bankfull width, bankfull depth, and channel capacity with increasing basin area for the non‐forested catchment has demonstrated that afforestation of the lower part of the catchment has had a marked effect on channel form. Channel widths within the forest are up to three times greater than that predicted from the regression. These changes in bankfull width have led to stream bed aggradation and the development of wide shallow channels within the forest, and channel capacities within the forest are over two times that predicted from the basin area. The relationship between channel sinuosity and valley gradient for non‐forested reaches of the river also indicated decreased sinuosity resulting from afforestation. These changes in channel form result from active bank erosion within the forest with coarse material being deposited within the channel as point‐bars and mid‐channel bars. Active bank erosion is largely attributed to the suppression by the forest of a thick grass turf and its associated dense network of fine roots, and secondly to the river attempting to bypass log jams and debris dams in the stream channel.
A pattern in the incidence of major coastal mudslides
Authors: Hutchinson J. N.
Published: February 2007

The communication considers eroding coastal cliffs which consist predominantly of stiff‐fissured clay overlying a more resistant stratum, the contact having a gentle component of coastwise dip. From the southern coasts of England, five such cliffs are described. In each of these a zone of dominant mudsliding exists, which stands out from the background of lesser mudslides and other forms of failure: the common feature is that in each case the zone of major mudsliding coincides closely with the length of cliff over which the base of the clay stratum lies within the tidal range, and generally within the upper part of this. It is suggested that this pattern results from optimum conditions for continuing stimulation of mudslide activity by toe erosion being reached in the above zone.
A statistical study of the cliff top slumps in part of the christchurch bay coastal cliffs
Authors: Barton M. E. , Coles B. J. , Tiller G. R.
Published: February 2007

A distinction is made between slumping and spalling. Slumping involves a compound slide with rotation and translation: the latter along one of the bedding plane shear surfaces in the Barton Beds. Spalling is an isolated failure of the exposed cliff face due to weathering. Where slumping is the dominant mode of cliff top recession, the latter is an incremental process with the increments being equal to the breadth of the slumps. A statistical study has been made of the breadth, length and plan area of 42 slumps observed over a 2 km stretch of the Christchurch Bay coastal cliffs and significant trends deduced.
Suspended sediment in rapid subsurface stormflow on a large field plot
Authors: Pilgrim David H. , Huff Dale D.
Published: February 2007

The occurrence of rapid movement of suspended sediment in subsurface stormflow on a large field plot in California is described. Concentrations of over 1000mgl−1 were recorded in storms of only low to moderate intensity. The observed sediment was composed of uniformly fine‐sized particles 4 to 8 μm in diameter. The mode of transport seems different from processes previously reported. Differences in sediment concentrations in different events, levels of 137Cs on the sediment, and several other types of evidence indicate that the sediment was detached and entrained at the ground surface by raindrop impact and that the water and sediment flow occurred mainly through macropores in the soil. As conditions similar to those at the study site are not uncommon, it seems probable that the phenomenon may occur in many regions.