bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of prior cold working on microstructural evolution of precipitation in Zn–22Al–2Cu alloy during aging
Authors: Dorantes-Rosales H. J. , López-Hirata V. M. , Saucedo-Muñoz M. L. , Hernández-Santiago F. , Esquivel-Gonzalez R.
Published: November 2006

The microstructural evolution of precipitation was characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and microhardness measurements during two different types of isothermal aging in a Zn–22Al–2Cu alloy. Solution treated samples were quenched and rolled at room temperature and then aged at 250°C for different times. The X-ray results showed that the decomposition of the βsss phase and the formation τ′ phase, during the aging treatment occurred by the following reactions βsss→ α + η + ϵ and α + ϵ→ η + τ′ respectively. Similar phase transformations were observed in the sample solution treated, quenched and then cold worked before aging condition, with a faster kinetics. Besides, the microstructure of the latter samples consists of equiaxial grains of the τ′, α and η phases. In contrast, the former sample showed a lamellar structure of the α and η phases. This difference of microstructure caused a slightly higher hardness in the samples without cold working. Furthermore, the aging process caused a decrease in hardness with aging time, which seems to be related to the coarsening process of the equilibrium phases for both heat treatments.
Structural, thermal, dielectric studies on sol–gel derived MgO from non-alkoxide route
Authors: Chowdhury A. , Kumar J.
Published: November 2006

Mg oxide powder has been synthesised by sol–gel process via a novel non-alkoxide route. The precursor Mg oxalate gel was characterised by morphology, pore size distribution and differential thermal analysis, Fourier transformation infrared, TEM, SEM and X-ray diffraction analysis. The TEM studies on this system are reported for the first time depicting a unique morphology. A comparison in the morphology and the dielectric constant values of the sol–gel derived MgO powder was carried out with MgO powder obtained by Mg ribbon oxidation process. The sol–gel derived MgO powder was characterised by dielectric constant measurement in the compacted form and it was observed to exhibit a dielectric constant value, quite matching with the polycrystalline MgO in thin film form.
Progressive immunoglobulin gene mutations in chronic lymphocytic leukemia: evidence for antigen-driven intraclonal diversification
Authors: Volkheimer Alicia D. , Weinberg J. Brice , Beasley Bethany E. , Whitesides John F. , Gockerman Jon P. , Moore Joseph O. , Kelsoe Garnett , Goodman Barbara K. , Levesque Marc C.
Published: November 2006

Somatic mutations of immunoglobulin genes characterize mature memory B cells, and intraclonal B-cell diversification is typically associated with expansion of B-cell clones with greater affinity for antigen (antigen drive). Evidence for a role of antigen in progression of intraclonal chronic lymphocytic leukemia (CLL) cell diversification in patients with mutated immunoglobulin genes has not been previously presented. We performed a single-cell analysis of immunoglobulin heavy and light chains in 6 patients with somatically mutated CLL-cell immunoglobulin genes and identified 2 patients with multiple related (oligoclonal) subgroups of CLL cells. We constructed genealogic trees of these oligoclonal CLL-cell subgroups and assessed the effects of immunoglobulin somatic mutations on the ratios of replacement and silent amino acid changes in the framework and antigen-binding regions (CDRs) of the immunoglobulin heavy and light chains from each oligoclonal CLL-cell population. In one subject, the amino acid changes were consistent with an antigen-driven progression of clonally related CLL-cell populations. In the other subject, intraclonal diversification was associated with immunoglobulin amino acid changes that would have likely lessened antigen affinity. Taken together, these studies support the hypothesis that in some CLL cases intraclonal diversification is dependent on antigen interactions with immunoglobulin receptors.
Human plasma fibrinogen is synthesized in the liver
Authors: Tennent Glenys A. , Brennan Stephen O. , Stangou Arie J. , O'Grady John , Hawkins Philip N. , Pepys Mark B.
Published: November 2006

Hereditary systemic amyloidosis caused by fibrinogen Aα-chain gene mutations is an autosomal dominant condition with variable penetrance, usually of late onset, and typically presents with nephropathy leading to renal failure. Amyloid deposits often develop rapidly in transplanted kidneys, and concomitant orthotopic liver transplantation has lately been performed in several patients with the hope of halting amyloid deposition. Fibrinogen is produced in vitro by hepatocytes but also by other human cell types, and although the liver is the source of plasma fibrinogen in vivo in rats, this is not known in humans. Transplantation of livers expressing wild-type fibrinogen into patients with variant fibrinogen amyloidosis provides a unique opportunity to establish the source of human plasma fibrinogen. We therefore characterized plasma fibrinogen Aα-chain allotypes by electrospray ionization mass spectrometry mapping of tryptic digests before and after liver transplantation. Before liver transplantation, fibrinogen amyloidosis patients with the Glu526Val Aα-chain variant had approximately equal proportions of peptide with the wild-type sequence TFPGFFSPMLGEFVSETESR, and with the amyloidogenic variant sequence TFPGFFSPMLGEFVSVTESR, as expected for individuals heterozygous for the mutation. After transplantation, only the wild-type sequence was detected, and the liver is thus the source of at least 98% of the circulation fibrinogen.
Application of Petri net based analysis techniques to signal transduction pathways
Authors: Sackmann Andrea , Heiner Monika , Koch Ina
Published: November 2006

Background

Signal transduction pathways are usually modelled using classical quantitative methods, which are based on ordinary differential equations (ODEs). However, some difficulties are inherent in this approach. On the one hand, the kinetic parameters involved are often unknown and have to be estimated. With increasing size and complexity of signal transduction pathways, the estimation of missing kinetic data is not possible. On the other hand, ODEs based models do not support any explicit insights into possible (signal-) flows within the network. Moreover, a huge amount of qualitative data is available due to high-throughput techniques. In order to get information on the systems behaviour, qualitative analysis techniques have been developed. Applications of the known qualitative analysis methods concern mainly metabolic networks. Petri net theory provides a variety of established analysis techniques, which are also applicable to signal transduction models. In this context special properties have to be considered and new dedicated techniques have to be designed.

Methods

We apply Petri net theory to model and analyse signal transduction pathways first qualitatively before continuing with quantitative analyses. This paper demonstrates how to build systematically a discrete model, which reflects provably the qualitative biological behaviour without any knowledge of kinetic parameters. The mating pheromone response pathway in Saccharomyces cerevisiae serves as case study.

Results

We propose an approach for model validation of signal transduction pathways based on the network structure only. For this purpose, we introduce the new notion of feasible t-invariants, which represent minimal self-contained subnets being active under a given input situation. Each of these subnets stands for a signal flow in the system. We define maximal common transition sets (MCT-sets), which can be used for t-invariant examination and net decomposition into smallest biologically meaningful functional units.

Conclusion

The paper demonstrates how Petri net analysis techniques can promote a deeper understanding of signal transduction pathways. The new concepts of feasible t-invariants and MCT-sets have been proven to be useful for model validation and the interpretation of the biological system behaviour. Whereas MCT-sets provide a decomposition of the net into disjunctive subnets, feasible t-invariants describe subnets, which generally overlap. This work contributes to qualitative modelling and to the analysis of large biological networks by their fully automatic decomposition into biologically meaningful modules.
Predictors of betel quid chewing behavior and cessation patterns in Taiwan aborigines
Authors: Lin Chin-Feng , Wang Jung-Der , Chen Ping-Ho , Chang Shun-Jen , Yang Yi-Hsin , Ko Ying-Chin
Published: November 2006

Background

Betel quid, chewed by about 600 million people worldwide, is one of the most widely used addictive substances. Cessation factors in betel quid chewers are unknown. The present study explores prevalence and the quit rate of betel quid chewing in Taiwan aborigines. Our goal was to delineate potential predictors of chewing cessation.

Methods

A stratified random community-based survey was designed for the entire aborigines communities in Taiwan. A total of 7144 participants were included between June 2003 and May 2004 in this study. Information on sociodemographic characteristics, such as gender, age, obesity, education years, marital status, ethnicity, and habits of betel quid chewing, smoking and drinking was collected by trained interviewers.

Results

The prevalence of betel quid chewers was 46.1%. Betel quid chewing was closely associated with obesity (OR = 1.61; 95% CI: 1.40–1.85). Betel quid chewers were most likely to use alcohol and cigarettes together. Quit rate of betel quid chewers was 7.6%. Betel quid chewers who did not drink alcohol were more likely to quit (OR = 1.89; 95% CI: 1.43–2.50). Alcohol use is a significant factor related to cessation of betel quid chewing, but smoking is not.

Conclusion

Taiwan aborigines have a high prevalence of betel quid chewers and a low quit rate. Alcohol use is strongly association with betel quid chewing. Efforts to reduce habitual alcohol consumption might be of benefit in cessation of betel quid chewing.
Does a joint development and dissemination of multidisciplinary guidelines improve prescribing behaviour: a pre/post study with concurrent control group and a randomised trial
Authors: Martens Jody D , Winkens Ron AG , van der Weijden Trudy , de Bruyn Daisy , Severens Johan L
Published: November 2006

Background

It is difficult to keep control over prescribing behaviour in general practices. The purpose of this study was to assess the effects of a dissemination strategy of multidisciplinary guidelines on the volume of drug prescribing.

Methods

The study included two designs, a quasi-experimental pre/post study with concurrent control group and a random sample of GPs within the intervention group. The intervention area with 53 GPs was compared with a control group of 54 randomly selected GPs in the south and centre of the Netherlands. Additionally, a randomisation was executed in the intervention group to create two arms with 27 GPs who were more intensively involved in the development of the guideline and 26 GPs in the control group.

A multidisciplinary committee developed prescription guidelines. Subsequently these guidelines were disseminated to all GPs in the intervention region. Additional effects were studied in the subgroup trial in which GPs were invited to be more intensively involved in the guideline development procedure. The guidelines contained 14 recommendations on antibiotics, asthma/COPD drugs and cholesterol drugs

The main outcome measures were prescription data of a three-year period (one year before and 2 years after guideline dissemination) and proportion of change according to recommendations.

Results

Significant short-term improvements were seen for one recommendation: mupirocin. Long-term changes were found for cholesterol drug prescriptions. No additional changes were seen for the randomised controlled study in the subgroup. GPs did not take up the invitation for involvement.

Conclusion

Disseminating multidisciplinary guidelines that were developed within a region, has no clear effect on prescribing behaviour even though GPs and specialists were involved more intensively in their development. Apparently, more effort is needed to bring about change.
Engaging Students in Learning: An Application with Quantitative Psychology
Authors: Harlow Lisa L. , Burkholder Gary J. , Morrow Jennifer A.
Published: November 2006

In response to calls for more engaging and interactive pedagogy, we simultaneously implemented 4 rousing learning activities: peermentored learning, student reports of what was clear (or not) from a previous lecture, consult corners where student groups provided course-informed solutions to problem-based scenarios, and applied projects presented to the class. Students in several sections of a quantitative psychology course responded positively, reporting significantly less anxiety and greater self-efficacy regarding quantitative topics at the end of the semester compared to the beginning. We provide suggestions for applying these learning activities to other psychology courses.
The Impact of Daily Extra Credit Quizzes on Exam Performance
Authors: Padilla-Walker Laura M.
Published: November 2006

This study examined whether offering daily extra credit quizzes predicted exam performance in an advanced psychology course ( n =36). Results revealed that extra credit performance was a strong predictor of exam performance, above and beyond gender, college grade point average, and ACT scores. In addition, results suggested that nearly half of the students reported their primary motivation for completing extra credit was to earn extra points toward their grade. This research has important pedagogical implications in highlighting the use of daily extra credit quizzes as a practice that facilitates learning and directly affects exam performance.
A Technology Classroom Review Tool for General Psychology
Authors: Paul Stephen T. , Hollis Alma M. , Messina John A.
Published: November 2006

We developed a computerized game designed around principles shown to improve classroom performance and experience: multimedia, practice testing, vivid instructional techniques, and in-class participation. Students compete as 2 teams, and the game plays like Jeopardy meets Hollywood Squares with learning outcomes. Our evaluation indicated that the game was effective in small to larger classes (28 to more than 50 students). We present data supporting the game's effectiveness, and we discuss students' reactions and data concerning self-reported effectiveness and perceived value.
Astressin B, a Corticotropin-Releasing Hormone Receptor Antagonist, Accelerates the Return to Normal Luteal Function after an Inflammatory-Like Stress Challenge in the Rhesus Monkey
Authors: Xiao Ennian , Xia-Zhang Linna , Vulliemoz Nicolas , Rivier Jean , Ferin Michel
Published: November 2006

Endogenous release of CRH in stress has been associated with a dysfunctional reproductive endocrine axis. In the rhesus monkey, an inflammatory-like stress challenge in the luteal phase decreases luteal secretory function. Here, we tested the effectiveness of astressin B, a nonspecific CRH receptor antagonist, in constraining the deleterious impact of a 10-d lipopolysaccharide (LPS) challenge on the menstrual cycle. Two protocols were carried out in nine animals. In the first, the animals, after showing two normal consecutive control cycles, were injected daily for 10 days with LPS (75–125 μg/d) during the luteal phase of the cycle. The animals were followed through the two postchallenge cycles. The second protocol, carried out in the following year, was identical with protocol 1, except that the animals were treated with astressin B (0.45 mg/kg) 1 h before each daily LPS challenge during the luteal phase. Blood samples were obtained daily to document cyclic hormones levels. The LPS challenge significantly decreased luteal progesterone and LH release during the challenge cycle. Inhibition of luteal progesterone extended to the two successive postchallenge cycles. Astressin B treatment prevented luteal LH but not luteal progesterone decrease during the treatment cycle and restored normal progesterone secretion during the two posttreatment cycles. We conclude that the deleterious impact of a short-term inflammatory stress challenge on luteal function is far longer than the stress period itself. Systemic administration of astressin B accelerates the return to normal luteal function, presumably by restoring normal neuroendocrine regulation of gonadotropin secretion.
Tandem Mass Spectrometry for the Direct Assay of Enzymes in Dried Blood Spots: Application to Newborn Screening for Mucopolysaccharidosis II (Hunter Disease)
Authors: Wang Ding , Wood Tim , Sadilek Martin , Scott C Ronald , Turecek Frantisek , Gelb Michael H
Published: November 2006

Background: A treatment for mucopolysaccharidosis II (Hunter syndrome) has recently become available. Therefore, we developed a high-throughput assay method appropriate for newborn screening for the relevant enzyme, iduronate 2-sulfatase.

Methods: We synthesized a new iduronate 2-sulfatase substrate that can be used to assay the enzyme by use of tandem mass spectrometry together with an internal standard. The assay uses a dried blood spot on a newborn screening card as the enzyme source.

Results: When the assay was tested on dried blood spots, the iduronate 2-sulfatase activity measured for 13 patients with Hunter syndrome was well below the interval found for 57 randomly chosen newborns. The assay was more sensitive than previously reported iduronate 2-sulfatase assays.

Conclusions: This newly developed tandem mass spectrometry assay has the potential to be adopted for newborn screening of Hunter syndrome. This method also has the potential to be carried out in multiplex fashion to assay several different enzymes relevant to lysosomal storage diseases that are assayed in a single infusion into the mass spectrometer.
N-Ethylmaleimide-sensitive factor: a redox sensor in exocytosis
Authors: Lowenstein Charles J. , Tsuda Hiromasa
Published: November 2006

Vascular injury triggers endothelial exocytosis of granules, releasing pro-inflammatory and pro-thrombotic mediators into the blood. Nitric oxide (NO) and reactive oxygen species (ROS) limit vascular inflammation and thrombosis by inhibiting endothelial exocytosis. NO decreases exocytosis by regulating the activity of theN-ethylmaleimide-sensitive factor (NSF), a central component of the exocytic machinery. NO nitrosylates specific cysteine residues of NSF, thereby inhibiting NSF disassembly of the soluble NSF attachment protein receptor (SNARE). NO also modulates exocytosis of other cells; for example, NO regulates platelet activation by inhibiting α-granule secretion from platelets. Other radicals besides NO can regulate exocytosis as well. For example, H2O2inhibits exocytosis by oxidizing NSF. Using site-directed mutagenesis, we have defined the critical cysteine residues of NSF, and found that one particular cysteine residue, C264, renders NSF sensitive to oxidative stress. Since radicals such as NO and H2O2inhibit NSF and decrease exocytosis, NSF may act as a redox sensor, modulating exocytosis in response to changes in oxidative stress.
Crystal structures of the new isotypic compounds Rb4(M2+)(Fe3+)8[SeO3]14[SeO2(OH)]2 · 2 H2O (M = Mg, Cu) with a short review on iron(III) selenites
Authors: Giester Gerald , Wildner Manfred
Published: November 2006

Single crystals of the new compounds Rb4(M2+)(Fe3+)8[SeO3]14[SeO2(OH)]2 · 2 H2O (M = Mg, Cu) have been synthesized in Teflon-lined steel vessels at 495 K. Their structures were determined from X-ray single crystal diffraction data and found to be isotypic: space group P-1, Z = 1, a = 7.716(2)/7.726(2), b = 10.325(3)/10.327(3), c = 15.764(4)/15.724(4) Å, α = 77.57(1)/77.87(1), β = 89.23(1)/89.47(1), γ = 86.09(1)/86.57(1)°, V = 1223.6(6)/1224.3(6) Å3, R1 = 0.028/0.037 for the Mg/Cu compound, respectively.

The structure type is characterized by a complex polyhedral framework: the [(Fe3+)O6] octahedra are linked via all corners with typical pyramidal [SeO3]2– groups — with exception of a H2O molecule which is a ligand of one of the Fe atoms. The [(M2+)O6] polyhedron shares two corners and two edges with selenite pyramids. Further sharing corners with [FeO6] octahedra, centrosymmetric units of the type [MFe4Se4O28] may be emphasized. Voids within the framework are occupied by Rb+ cations and by the lone-pair electrons of the Se4+ cations. Three different hydrogen bonds with O···O distances in the range 2.69–2.85 Å occur.

At present 28 selenites of ferric iron are known, most of them synthesized at low-hydrothermal conditions. Commonly, framework structures are formed with ferric iron in octahedral coordination. Further building units are trigonal pyramidal [SeO3]2– and [SeO2(OH)]– groups or [Se2O5]2– dimer anions, featuring a large variety of structure arrangements. Iron(III) selenites are classified based on the presence of extra cations, on the respective anionic groups and by the type of interpolyhedral linkage. In the literature, few isotypic selenites (with Fe3+ substituted by another trivalent cation) have been reported yet.

Among 51 [FeOn] polyhedra studied all but one show ferric iron (Fe3+) in sixfold coordination with mean Fe—O bond lengths for 41 pure [FeO6] octahedra ranging from 1.989 to 2.044 Å with an overall mean value of 2.013(11) Å. Remarkably, only 14% of all [FeO6] poly hedra are centrosymmetric.

In the oxoanions investigated (61 [SeO3]2–, 9 [SeO2(OH)]– and 6 [Se2O5]2– groups) tetravalent selenium typically forms a flattened trigonal pyramid with O—Se—O bond angles of about 100° and Se—O bond lengths of 1.70 Å, completed by the lone-pair electrons E at the selenium cation to a formal [ESeO3]2–
ψ
1 tetrahedron. In hydrogenselenites and diselenites elongated Se—O distances occur for the protonated and the bridging oxygen atoms, respectively. With some rare exceptions all selenium atoms have the site symmetry 1.
“Those Anime Students”: Foreign Language Literacy Development Through Japanese Popular Culture
Authors: Fukunaga Natsuki
Published: November 2006

Using multiliteracies and sociocultural perspectives on language and literacy learning, this article describes three Japanese as a foreign language (JFL) students' literacy development through involvement with Japanese popular culture. As part of a larger qualitative ethnographic study, the author interviewed JFL learners who have a particular interest in Japanese popular culture. Analysis suggests that JFL learners develop literacy skills such as word recognition, listening, and pronunciation in the social contexts provided by anime, or Japanese animation. It appears that “anime students” are simultaneously developing foreign language literacy skills, taking up a critical stance toward media, and constructing identities within anime culture.
Chronic total occlusion angioplasty through supplying collaterals
Authors: Kumar Sridhar Sampath , Kaplan Barry
Published: November 2006

Chronic total occlusions are typically difficult to recannalize especially when adverse angiographic morphologies are identified. We describe a case of chronic total occlusion crossing retrograde through the supplying collaterals followed by successful angioplasty and stenting. © 2006 Wiley‐Liss, Inc.
A new understanding of chronic total occlusion from a novel PCI technique that involves a retrograde approach to the right coronary artery via a septal branch and passing of the guidewire to a guiding catheter on the other side of the lesion
Authors: Ozawa Noriyuki
Published: November 2006

Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) by the antegrade approach is sometimes difficult, especially in the right coronary artery (RCA). We performed successful PCls following a retrograde approach via a septal branch in 2 patients with CTO in RCA. The method involves leading the retrograde guidewire outside the body through an opposite guiding catheter after the wire crosses the target lesion. A balloon or stent could then be delivered retrogradely or antegradely. Even a soft retrograde wire always crosses the lesion through the true lumen, as confirmed by IVUS. Selecting a suitable collateral, a straighter rather than a larger one, is crucial. Our results do not support the current concept regarding CTOs. Probably, the distal fibrous cap is soft and the proximal one has a thin point that soft wires, even blunt ones, can penetrate easily. The distal penetration point appears to connect to the proximal uncalcified thin point. Many channels seem to spread out from the proximal side, tree‐like, within the lesion. In the retrograde approach, the wire is unlikely to enter these branch channels. The results suggest that PCI by the retrograde approach may be effective for treating CTOs of RCA. © 2006 Wiley‐Liss, Inc.
Mastering the antegrade femoral artery access in patients with symptomatic lower limb ischemia: Learning curve, complications, and technical tips and tricks
Authors: Biondi‐Zoccai Giuseppe G. L. , Agostoni Pierfrancesco , Sangiorgi Giuseppe , Paola Luca Dalla , Armano Fabio , Nicolini Simone , Alek Josef , Fusaro Massimiliano
Published: November 2006

Background: Antegrade femoral access is fraught by technical challenges and steeper learning curve, in comparison with retrograde contralateral femoral access. We appraised learning curve, complications, and technical aspects inherent in the adoption of antegrade approach. Methods: Consecutive cases in which antegrade access was attempted by a cardiologist experienced in retrograde access, but inexperienced in antegrade, under supervision of an operator with anterograde expertise, were collected. The primary end‐point was the occurrence of antegrade access failure or local complications. Major complications were defined as those life‐threatening, requiring transfusion, percutaneous, or surgical repair. Results: Anterograde access was attempted in 120 patients. The primary end‐point occurred in 14 (11.6%) cases, but according to the learning curve, in 12 (20%) for first 60 cases vs 2 (3.3%) for the last 60 cases (P = 0.008). Access failure in the hands of the in‐training operator was similarly found in all cases but one during the first 60 cases. No major complications occurred, while minor complications were found in 9 (7.5%) patients, again with all but two of them occurring in the first 60 cases. These included peri‐adventitial extravasation in 8 patients (6.7%), and perforation of a small branch in one (0.8%); all these complications were conservatively and successfully managed. Obesity was the only significant predictor of access failure/complication (P = 0.004). Conclusions: This work, the first to report on the learning curve of the antegrade approach, supports the feasibility and safety of this access site even for an in‐training operator, if supervised. A minimum caseload of 60 procedures is likely needed to master this technique. © 2006 Wiley‐Liss, Inc.
QSAR Studies on a Series of 7,8‐Dialkyl‐1,3‐diaminopyrrolo‐[3,2‐f]quinazolines with Anticancer Activity
Authors: Chen Jin‐Can , Qian Li , Shen Yong , Chen Lan‐Mei , Zheng Kang‐Cheng
Published: November 2006

The quantitative structure‐activity relationship (QSAR) studies on a series of 7,8‐dialkyl‐1,3‐diaminopyrrolo‐[3,2‐f]quinazolines, dihydrofolate reductase (DHFR) inhibitors as potential anticancer agents, have been carried out by using the density functional theory (DFT) method, molecular mechanics method (MM+) and statistical method. Some QSAR models based on their lipophilic and steric parameters were built up via a stepwise regression analysis. It is very interesting to find that the established optimal QSAR equation involves only two descriptors: lipophilicity indexes Clog P and Clog P2. However, such descriptors can quite well describe a significant statistic quality and have a remarkable predictive activity according to the square of adjusted correlation coefficient (R2A=0.937) and the square of cross‐validation coefficient (q2=0.911) of this equation. The results show that the lipophilicity is a main factor affecting the anticancer activity of this series of antimetastatic agents, and the obtained equation describes a parabolic correlation between pIC50 and Clog P, and indicates a suitable range of Clog P (around 4.43) being very important for optimal pIC50 values. These QSAR studies can offer some useful references for understanding the action mechanism and performing the molecular design or modification of this series of antimetastatic agents.
Synthesis and Antifungal Activity of Novel Chiral α‐Aminophosphonates Containing Fluorine Moiety
Authors: Yang Song , Gao Xing‐Wen , Diao Chun‐Ling , Song Bao‐An , Jin Lin‐Hong , Xu Guang‐Fang , Zhang Guo‐Ping , Wang Wei , Hu De‐Yu , Xue Wei , Zhou Xia , Lu Ping
Published: November 2006

Chiral α‐aminophosphonates were synthesized using (R) or (S)‐1‐phenylethylamine in the presence of BF3·Et2O under microwave irradiation in moderate to good yields. The new compounds were identified by 1H NMR, 19F NMR, IR and elemental analysis. Their antifungal activities were evaluated and some compounds were found to exhibit excellent antifungal activities. To the best of our knowledge, this is the first report on antifungal activity of chiral α‐aminophosphonates containing fluorine moiety.
Aminoalkylbis(phosphonates): Their Complexation Properties in Solution and in the Solid State
Authors: Kubíček Vojtěch , Kotek Jan , Hermann Petr , Lukeš Ivan
Published: November 2006

Five geminal bis(phosphonates) containing an amino group in the α, γ or δ position of the carbon chain have been synthesised and their acid–base and complexation properties with Cu2+, Zn2+, Ca2+, Mg2+ and Na+ ions studied by potentiometry. Determination of the stability constants of the complexes with divalent metal ions is complicated by the formation of precipitates. The results of these studies show a negligible effect of the hydroxo group in the α position on the acid–base and complexation properties of the ligands. The presence of an amino group in the α position, however, decreases the basicity, which results in a lower complexation ability of the bis(phosphonates). The crystal structures of the three ligands with different degrees of protonation have also been determined. The structure of the triammonium salt of aminomethylbis(phosphonic acid) shows that the proton is bound to the nitrogen atom in monoprotonated species. The structure of the Cu2+ complex of pamidronate [{Cu2(H2pam)2}·H2O]n shows the presence of dimeric units with a relatively short distance (2.99 Å) between the metal centres. These units form a coordination polymeric chain. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Crystal Structure, Solid‐State NMR Spectroscopic and Photoluminescence Studies of Organic‐Inorganic Hybrid Materials (HL)6[Ge6(OH)6(hedp)6]·2(L)·nH2O, L = hqn or phen
Authors: Mafra Luís , Almeida Paz Filipe A. , Shi Fa‐Nian , Sá Ferreira Rute A. , Carlos Luís D. , Trindade Tito , Fernandez Christian , Klinowski Jacek , Rocha João
Published: November 2006

Two germanium–hedp4– solids with heteroaromatic amines 8‐hydroxyquinoline (hqn) and 1,10‐phenanthroline (phen), (HL)6[Ge6(OH)6(hedp)6]·2(L)·nH2O (L = hqn or phen), in I and II respectively, have been prepared and characterised by single‐crystal XRD, thermogravimetry, FTIR and UV/Vis spectroscopy. The complex hydrogen‐bond networks, particularly in compound I, have been studied by advanced high‐resolution solid‐state NMR spectroscopy that combines homonuclear recoupling techniques (two‐dimensional 1H‐1H DQF and 1H‐1H RFDR MAS NMR) and combined rotation and multiple‐pulse spectroscopy (two‐dimensional 1H‐1H FS‐LG, 1H‐31P FS‐LG). The fine details of the crystal structure of I have been elucidated, mainly those involving the π–π stacking of 8‐hydroxyquinoline and the relative orientation of adjacent such molecules. Compound II exhibits an emission from the lowest triplet‐state energy (π–π* 0‐phonon transition) of the aromatic rings at 320 nm (31250 cm–1) from 14 K to room temperature. In contrast, the triplet emission of I at 530 nm (18868 cm–1) is only detected at low temperature, because of thermally activated non‐radiative mechanisms. The emission spectra of I and II display a lower‐energy component with a larger life time, which results from the formation of an excimer state that originated from the π–π phenanthroline and hydroxyquinoline interactions, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Logistic mixture of multivariate regressions for analysis of water quality impacted by agrochemicals
Authors: Joo Yongsung , Lee Keunbaik , Min Joong‐Hyuk , Yun Seong‐Taek , Park Trevor
Published: November 2006

In this paper, we study the impacts of two representative agricultural activities, fertilizers and lime application, on water quality. Because of heavy usage of nitrogen fertilizers, nitrate (NO) concentration in water is considered as one of the best indicators for agricultural pollution. The mixture of normal distributions has been widely applied with (NO) concentrations to cluster water samples into two environmentally interested groups (water impacted by agrochemicals and natural background water groups). However, this method fails to yield satisfying results because it cannot distinguish low‐level fertilizer impact and natural background noise. To improve performance of cluster analysis, we introduce the logistic mixture of multivariate regressions model (LMMR). In this approach, water samples are clustered based on the relationships between major element concentrations and physicochemical variables, which are different in impacted water and natural background water. Copyright © 2006 John Wiley & Sons, Ltd.
Zur Gewinnung von niederverestertem Pektin aus technischen Apfelpektinextrakten mit Ammoniak: Einfluß der Entesterungsbedingungen auf das Geliervermögen
Authors: Bock W. , Lange D.
Published: November 2006

Ausgehend von den in der Literatur angegebenen chemischen und enzymatischen Entesterungsverfahren wird anhand von orientierenden Versuchen festgestellt, daß zur Gewinnung von niederveresterten Pektinen hoher Qualität aus Apfeltrockentrestern praktisch nur zwei Arbeitsweisen von Bedeutung sind, nämlich die partielle Entesterung des Protopektins im flüssigkeitsarmen Zustand mit Salzsäure sowie die teilweise Verseifung der Pektinextrakte mit Ammoniak.

In systematischen Versuchen wird die ammoniakalische Entesterung von gelösten Apfelrohpektinen in Abhängigkeit vom pH‐Wert sowie der Reaktionstemperatur mit Hilfe einer entwickelten Schnellmethode näher untersucht, die eine direkte Ermittlung des Veresterungsgrades im Reaktionsmedium gestattet.

Unter Berücksichtigung des Geliervermögens (Wassergeliergrade) der dargestellten niederveresterten Pektine ergibt sich, daß die Qualität der Präparate mit steigender Temperatur bei der Verseifung im Bereich von 10–30 °C kontinuierlich abnimmt. Das Optimum der Gelierfähigkeit wird beim Arbeiten bei 10–15 °C erhalten.

Eine sichere Einflußnahme des pH‐Wertes bzw. der Ammoniakkonzentration bei der Entesterung auf das Geliervermögen der niederveresterten Pektine wird nicht gefunden.
Über die Anwendung der papierchromatographischen Analyse auf dem Fettgebiet. 4. Mitt. Über ölsäurereiche Samenöle. Ermittlung der konstituierenden Fettsäuren der Samenöle von Margosa (Azadirachta indica), Cashewkern (Anacardicum occidentale) und Putranjiva Roxburghii
Authors: Chowdhury D. K. , Mukherjea R. N.
Published: November 2006

Anhand des Schrifttums und eigener Erfahrungen wird über die möglichen Komplikationen berichtet, die sich der papyrographischen Analyse der Gesamtfettsäuren von natürlichen Fetten und Ölen in Abhängigkeit von Art und Menge der konstituierenden Fettsäuren entgegenstellen.

Durch Begrenzung des Imprägnierungsgrades des Papieres (Cerosin/Essigsäure) auf 0,1 und bei Anwendung einer 99,5%igen — anstatt der bisher üblichen 95%igen — Essigsäure als Fließmittel kann die Differenzierung der gesättigten Fettsäuren bis C26 erheblich verbessert werden.

Mittels der “Quecksilber‐Addukt‐Methode” ist bei Anwendung der beschriebenen Arbeitsweise die Trennung der Gesamtfettsäuren in die Fraktionen der gesättigten und der ungesättigten Vertreter mit gutem Ergebnis durchführbar.

Die Verfahren zur Darstellung von reiner Palmitolein‐, Myristin‐ und Arachinsäure werden beschrieben.

Zur Analyse der Gesamt fettsäuren ölsäurereicher natürlicher Öle — unter Einbeziehung der Bestimmung der Palmitoleinsäure — wird eine Kombination der “Quecksilber‐Addukt‐Methode” bzw. der “Hydrier‐Differenz‐Methode” mit der qualitativ und quantitativ papyrographischen Arbeitsweise herangezogen.

Für die Samenöle von Margosa, Cashewkernen und Putranjiva Roxburghii werden die Kennzahlen sowie die qualitative und quantitative Zusammensetzung hinsichtlich der konstituierenden Fettsäuren mitgeteilt.

Erstmals wird gezeigt, daß die Samenöle von Margosa und von Putranjiva Roxburghii Palmitoleinsäure in einer Menge von 1,8 bzw. 2,6% enthalten, bezogen auf die Gesamtfettsäuren.
Die Dämpfung polarographischer Maxima als eines der Kriterien für die Bewertung von Kunststoffen
Authors: Horáček J. , Malkus Z.
Published: November 2006

Es wird vorgeschlagen, die Unterdrückung von Sauerstoffmaxima polarographischer Kurven durch wäßrige Extrakte von Plasten als eines der allgemeinen Kriterien zur Beurteilung der herausgelösten Substanzen heranzuziehen. Auf Grund von Modellversuchen und Untersuchungen an Kunststoffen wird vorgeschlagen, daß bei gesundheitlich unbedenklichen Plasten — unter standardisierten Bedingungen — die Unterdrückung des Sauerstoffmaximums 50% nicht übersteigen sollte.
Röntgenologische Verdauungsstudien. Sekretorik und Motorik von Magen und Dünndarm nach Zufuhr verschiedener Fischzubereitungen
Authors: Canzler H. , Glatzel H.
Published: November 2006

Im Bemühen um die Erarbeitung physiologischer Grundlagen für die ärztliche Diätetik wurden bei 7 gesunden männlichen Vp nach je 3 verschiedenen Fischgerichten landesüblicher Art — Kochfisch, Bratfisch, Essigfisch — die Entleerungsgeschwindigkeit des Magens, die Sekretionsintensität, die Peristaltik, die Verweildauer im Magen und die Passage durch Jejunum und Ileum innerhalb von 3 Std. röntgenologisch verfolgt und in regelmäßigen Abständen im Bild festgehalten.

Der Ablauf aller röntgenologisch erfaßbaren Verdauungsvorgänge wird durch die individuelle Reaktionsform des Menschen bestimmt und ist weitgehend unabhängig von der speziellen Beschaffenheit des Fischgerichtes.

Fischfilet ist sowohl als Kochfisch wie als Bratfisch und Essigfisch ein “leicht verdauliches” Gericht. Unbekömmlichkeit im Einzelfall beruht nicht auf der Eigenart des speziellen Fischgerichtes, sondern auf der speziellen Reaktionsform des Individuums.

150 g Fischfilet sind “leichter verdaulich” als 100 g Roggenvollkornschrot oder Weizenfeinbrot.

Der Ablauf der späteren Verdauungsphasen — Motorik und Sekretorik von Magen, Jejunum und Ileum von der 2.— 3. Std. p.c. an — ist durch Individualität und Nahrungsart viel weniger stark modifizierbar als der Ablauf der früheren Phase. Es scheint, daß die Verträglichkeit eines Nahrungsmittels bzw. eines Gerichtes hauptsächlich vom Ablauf der sekretorischen und motorischen Verdauungsfunktionen während der frühen Verdauungsphase des Magens abhängt.
Studium der Wirkung der Gammastrahlung auf die L‐Ascorbinsäure
Authors: Tomaňa M. , Švábenský O. , Otta K.
Published: November 2006

Die Wirkung ionisierender Strahlung auf die L‐Ascorbinsäureoxydation in Modellösungen und Obst wurde verfolgt. Es wurde ermittelt, daß der Oxydationsverlauf der L‐Ascorbinsäure im Bereich der untersuchten Dosen und Konzentrationen der L‐Ascorbinsäure linear ist. Die Oxydationsgeschwindigkeit ist der L‐Ascorbinsäurekonzentration und der Strahlungsintensität indirekt proportional. Eine ähnliche Beziehung gilt auch für die weitere, jedoch langsamer verlaufen‐den Destruktion der Dehydroascorbinsäure. Die Reaktionsgeschwindigkeit der L‐Ascorbinsäure wird weiterhin durch niedrige pH‐Werte und bei Gegenwart von Sauerstoff und Schwermetall‐ionen erhöht. Nicotinsäure und Katalase weisen eine Schutzwirkung bezüglich der Ascorbinsäure auf. Die L‐Ascorbinsäureretention bei durch ionisierende Strahlen behandeltem frischem Obst ist auch bei längerer Lagerungsfrist günstig.
Zur Fischkühlung in Eis und Seewasser
Authors: Herrmann J. , Wolschon A.
Published: November 2006

Bei Lufttemperaturen von 10 °C ist Kühlhaltung in Eis nicht mehr gewährleistet, Seewasserkühlung bringt bessere Ergebnisse.

Bei kurzzeitiger Seewasserlagerung (2‐3 Tage) kann eine Verlängerung der Haltbarkeit um ca. 30% erzielt werden. In dieser Zeit treten noch keine Quellungserscheinungen auf; die Bearbeitung ist also noch nicht erschwert.

Bei Seewasserlagerung muß ständig das Wasser gereinigt und z. T. erneuert werden, um eine Anreicherung mit Eiweißteilchen und Fäulnisprodukten zu verhüten.

Eine zusätzliche bakterielle Infektion durch das Kühlwasser ist bei kurzer Lagerung nicht zu befürchten.

Die Kühlung durch Seewasser verläuft schneller und kann die Totenstarre und damit auch die Haltbarkeit verlängern.

Bei tiefen Lufttemperaturen (o bis +4 °C) sind die Unterschiede zwischen beiden Lagerungsverfahren unwesentlich und lediglich im Äußeren der Fische wahrzunehmen.
Untersuchungen über Polygalakturonase‐Enzyme aus Schimmelpilzen VI. Mitt. Eigenschaften der Polygalakturonasen aus Schimmelpilzen
Authors: Nyeste L. , Holló J. , Kovács L.
Published: November 2006

Es werden Temperaturoptima von drei pektinzersetzenden Enzympräparaten aus Schimmelpilzen bei verschiedenen Inkubationszeiten bestimmt, wobei das Präparat eines Asp.‐niger‐ Stammes den höchsten Wert aufweist.

Die von 9 Polygalakturonase‐Enzympräparaten ermittelten pH‐Optima werden mit Angaben aus der Literatur verglichen.

Die pH‐Aktivitätskurven der pektinzersetzenden Enzympräparate weisen mehrere Maxima auf, was darauf hinweist, daß die geprüften Schimmelpilze ein Polygalakturonase‐System mit mehreren Komponenten besitzen.
Untersuchungen über die Verwertung von Calcium‐ und Phosphorsalzen aus Fischgrätenmehl einiger Frischfische und Fischkonserven bei der Verfütterung
Authors: Doboszýnska B. , Ganowiak Z. , Wierzchowski J.
Published: November 2006

Zur Prüfung der Verwertung von Calcium und Phosphor aus Knochenmehl von frischen und konservierten Fischen erhielten junge Ratten neben der Grunddiät (STEENBOCK Nr. 2935, mit bzw. ohne Calciumcarbonat; Kontrollgruppen) einen Zusatz von 5% des jeweiligen Knochenmehles.

Aus dem Umfang des Verkalkungsgrades sowie des Calcium‐ und Phosphor‐Gehaltes der Rattenknochen kann auf eine gute Aufnahme der genannten Mineralien aus den frischen und konservierten Fischen gefolgert werden.

Daneben zeigen die verfütterten Fischgrätenmehle eine gute prophylaktische antirachitische Wirkung auf junge Ratten.
Untersuchungen über den Einfluß unterschiedlicher Brotnahrung auf die Körperentwicklung wachsender Albinoratten
Authors: Thomas B. , Ketz H.‐A. , Tunger L. , Erhardt V.
Published: November 2006

Zur Prüfung des Einflusses der Krumenqualität, des Ausmahlungsgrades und der Zubereitung von Brot und Getreideerzeugnissen auf die Entwicklung junger Ratten wurden in begrenzter Versuchsdauer von 60 bzw. 120 Tagen die Futter‐ und Wasseraufnahme und die Gewichtsveränderungen täglich festgestellt und Messungen einzelner Verdauungsorgane nach Sektion vorgenommen. Zur Untersuchung gelangten Brot und Brei aus dem Endosperm und dem Vollkorn von Roggen und Weizen sowie roher Roggen. Das Versuchsfutter bestand nur aus Brot ad libitum und zusätzlich Vitamin A.

Für die Beurteilung des Einflusses der Krumenqualität erwiesen sich die Tiere als ungeeignet. Zur Einschätzung der Nährwertveränderungen in Abhängigkeit von Ausmahlungsgrad und Zubereitung ergab sich, daß die mit Endosperm gefütterten Tiere im Vergleich zu den Tieren mit Futter aus dem gleichen Vollkorn langsamer wuchsen, anfälliger waren (häufiger Exitus), kleinere Verdauungsorgane hatten und erhöhte Flüssigkeitsmengen aufnahmen. Hinsichtlich der Zubereitung ergab sich, daß Futter aus Brei zu höheren Wachstumswerten führte als aus Brot und daß rohes Korn beiden Zubereitungsarten überlegen war, wenn die Eingewöhnung in früher Jugendentwicklung der Tiere erfolgte.
Bestimmung der Jodzahl von Fetten und Ölen mittels N‐Bromsuccinimid. 2. Mitt. Über eine Möglichkeit zur Bestimmung der Gesamtjodzahl von Eläostearinsäure und Holzöl
Authors: Jovtscheff A. , Bontscheff N. , Jonkow D.
Published: November 2006

Es wird ein Verfahren zur Bestimmung der Gesamtjodzahl von Eläostearinsäure und Holzöl mittels N‐Bromsuccinimid‐Reagenz (N‐Bromsuccinimid in Eisessig gelöst) bei einer Einwirkungsdauer von etwa 24 Std. des Reagenzes bei Raumtemperatur auf die Probe vorgeschlagen. Das Verfahren wurde mit der Methode von Chowdhury und Mukherjee verglichen. Die Genauigkeit des Verfahrens mittels N‐Bromsuccinimid wird charakterisiert durch die relative Standardabweichung in Prozent V = ± 0,9%.
Eine Schnellmethode zur Wasserbestimmung in Bonbonmassen
Authors: Wolf G. , Dorn H.
Published: November 2006

Es wird über eine Schnellmethode zur Wasserbestimmung in fettfreien Karamelmassen berichtet und eine Korrekturtabelle für das in der DDR zur Herstellung von Bonbonmassen allgemein übliche Zucker‐Stärkesirup‐Verhältnis angegeben.
Oxydative Abbauprodukte der L‐Ascorbinsäure 2. Mitt. Polarographischer Nachweis
Authors: Herrmann J. , Andrae W.
Published: November 2006

Auf polarographischem Wege wurde bisher die Ascorbinsäure, Dehydroascorbinsäure und Diketogulonsäure erfaßt, wobei sich jedoch die Stufe der Dehydroascorbinsäure nicht für analytische Zwecke eignet, da sie polarographisch nur unter Verwendung der Reinsubstanz, nicht aber im Verlauf der Ascorbinsäure‐Oxydation gefunden wird.

In Verfolgung der Oxydation einer wäßrigen Ascorbinsäure‐Lösung gelang uns der polarographische Nachweis von Dehydroascorbinsäure sowohl mittels einer neuen Reduktions‐ als auch Oxydationsstufe. Nach Einsatz kristalliner Dehydroascorbinsäure als Testsubstanz wurden diese Stufen sowie die bereits aus der Literatur bekannte Reduktionsstufe bestätigt.

Durch Überführung oxydierter Ascorbinsäure‐Lösung in ammoniakalischen Puffer ist die direkte, gleichzeitige Bestimmung von Ascorbinsäure, Dehydroascorbinsäure und Diketogulonsäure in einem Analysengang möglich.

Die vergleichende Messung der polarographisch erfaßten Reaktionsprodukte gestattet einen Einblick in den Oxydationsverlauf der Ascorbinsäure.

Die Arbeit wird fortgesetzt.