bluuebunny/crossref_metadata_2025 huggingface dataset:
Drosophila Poly(ADP-Ribose) Glycohydrolase Mediates Chromatin Structure and SIR2-Dependent Silencing
Authors: Tulin Alexei , Naumova Natalia M , Menon Ammini K , Spradling Allan C
Published: October 2005

Protein ADP ribosylation catalyzed by cellular poly(ADP-ribose) polymerases (PARPs) and tankyrases modulates chromatin structure, telomere elongation, DNA repair, and the transcription of genes involved in stress resistance, hormone responses, and immunity. Using Drosophila genetic tools, we characterize the expression and function of poly(ADP-ribose) glycohydrolase (PARG), the primary enzyme responsible for degrading protein-bound ADP-ribose moieties. Strongly increasing or decreasing PARG levels mimics the effects of Parp mutation, supporting PARG's postulated roles in vivo both in removing ADP-ribose adducts and in facilitating multiple activity cycles by individual PARP molecules. PARP is largely absent from euchromatin in PARG mutants, but accumulates in large nuclear bodies that may be involved in protein recycling. Reducing the level of either PARG or the silencing protein SIR2 weakens copia transcriptional repression. In the absence of PARG, SIR2 is mislocalized and hypermodified. We propose that PARP and PARG promote chromatin silencing at least in part by regulating the localization and function of SIR2 and possibly other nuclear proteins.
Variation in Mutation Dynamics Across the Maize Genome as a Function of Regional and Flanking Base Composition
Authors: Morton Brian R , Bi Irie V , McMullen Michael D , Gaut Brandon S
Published: October 2005

We examine variation in mutation dynamics across a single genome (Zea mays ssp. mays) in relation to regional and flanking base composition using a data set of 10,472 SNPs generated by resequencing 1776 transcribed regions. We report several relationships between flanking base composition and mutation pattern. The A + T content of the two sites immediately flanking the mutation site is correlated with rate, transition bias, and GC → AT pressure. We also observe a significant CpG effect, or increase in transition rate at CpG sites. At the regional level we find that the strength of the CpG effect is correlated with regional A + T content, ranging from a 1.7-fold increase in transition rate in relatively G + C-rich regions to a 2.6-fold increase in A + T-rich regions. We also observe a relationship between locus A + T content and GC → AT pressure. This regional effect is in opposition to the influence of the two immediate neighbors in that GC → AT pressure increases with increasing locus A + T content but decreases with increasing flanking base A + T content and may represent a relationship between genome location and mutation bias. The data indicate multiple context effects on mutations, resulting in significant variation in mutation dynamics across the genome.
Facing contribution to seismic response of reduced-scale reinforced soil walls
Authors: El-Emam M. M. , Bathurst R. J.
Published: October 2005

The behavior of six reduced-scale reinforced soil walls under base excitation is investigated using physical shaking table tests. The models were tested to isolate the influence of facing geometry, facing mass and facing toe condition on response to simulated seismic loading. The walls were instrumented to measure facing lateral displacement, reinforcement strain, toe reaction loads and accelerations. The model walls were constructed with a structural facing and polymeric geogrid reinforcement layers and subjected to a stepped amplitude sinusoidal base input acceleration. The toe boundary condition and facing panel configuration were found to have a significant effect on model response. For example, the magnitude of the accumulated facing lateral displacement at the top of the vertical wall models and at the same base acceleration magnitude was less for vertical walls with a less massive facing panel regardless of toe boundary condition. For the same boundary condition, a wall with an inclined facing displaced less than the nominal identical vertical wall for the same base excitation level. The horizontally restrained toe in reduced-scale models attracted approximately 40% to 60% of the peak total horizontal earth load during base excitation, demonstrating that a stiff facing column plays an important role in resisting dynamic loads under simulated earthquake loading. Measured footing and reinforcement loads are compared with values predicted using current pseudo-static analysis and design methods for geosynthetic-reinforced soil walls, and the implications of differences in predicted to measured values to current North American design practice are identified.
Dilatant stresses at the interface of granular fills and geogrid strip reinforcements
Authors: Alfaro M. C. , Pathak Y. P.
Published: October 2005

Design guidelines for geosynthetic-reinforced soil walls recommend the use of densely compacted granular soils as select fills. The prevailing construction practices employ two reinforcement layouts. In one, geosynthetics are laid out continuously throughout the length of reinforced area (sheet reinforcement): this layout is usually associated with wrap-around and modular block-type facing units. In the other, geosynthetics are laid out discretely (strip reinforcement): this is usually associated with panel-type facing units. These two reinforcement layouts interact differently with densely compacted granular fills, which are inherently dilatant. Sheet reinforcement corresponds to a free dilatancy condition whereas strip reinforcement corresponds to a restrained dilatancy condition. The effect of restrained dilatancy results in an increase in normal stresses or mobilization of dilatant stresses at the soil–reinforcement interface during reinforcement pullout and in turn generates additional localized compressive stresses in the surrounding granular fill. This has a generally positive influence because it enhances the pullout resistance of the reinforcement and also raises the effective stresses, resulting in an increase in the shear strength of the granular fill and thus improving the internal stability of reinforced soil walls. This paper presents an extension to earlier work by Alfaro et al. on the pullout interaction mechanisms of geogrid strip reinforcements. It examines the mobilization of dilatant stresses at the soil–reinforcement interface during reinforcement pullout. The study shows that it is essential to take into account the influence of dilatant stresses in the internal stability analysis of reinforced soil walls that use geogrid strip reinforcements.
Stability of modified geotextile wrap-around revetments (GWR) for coastal protection
Authors: Recio-Molina J. , Yasuhara K.
Published: October 2005

New shore protection structures are increasingly being required, especially for sandy beaches. In this study, modifications to the geometry of geotextile wrap-around revetments (GWR) and the influence of two different geosynthetics were investigated using small-scale model tests. GWR structures were constructed in a wave flume and subjected to different types of regular wave. Stability and deformation analyses were conducted, along with a comparison between conventional GWR structures and modified systems. The influence of the foundation and scouring was also investigated. Finally, a modified GWR structure design with greater stability and flexibility is presented. Modifications consisted of sewing the geotextile layers together in order to create a homogeneous revetment. Model test results and analyses showed that these modified GWR structures have greater stability and resistance to scour erosion, and therefore are a practical alternative to conventional revetment structures for coastal protection.
Correlation between the results of creep and relaxation tests of geotextiles
Authors: Kazimierowicz-Frankowska K.
Published: October 2005

The time-dependent behaviour of geosynthetics is characterised by creep and relaxation curves. The isochronous curves derived from creep results are sometimes used to predict the relaxation behaviour of geosynthetics. The validity and precision of such an approach are investigated in this paper. Using experimental data from in-isolation creep and relaxation tests performed on selected types of geotextile, the validity and limitations of using creep isochronous curves to predict relaxation response of these materials have been investigated. The conclusions are presented in the paper.
Antibody Treatments of Inflammatory Arthritis
Authors: Brown Matthew A.
Published: October 2005

Inflammatory arthropathies such as rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis are extremely common in the community, with a prevalence of up to 5%, and they cause substantial morbidity. The development of anti-TNF agents for use initially in rheumatoid arthritis, and subsequently more broadly in inflammatory arthritis, represents the biggest advance in management of these conditions since the introduction of corticosteroid agents, and is a major vindication of public funded arthritis research. However, there are limitations of even these highly effective agents. A significant minority of patients with inflammatory arthritis do not respond to these anti-TNF agents, they are associated with substantial risk of toxicity, require parenteral administration, and are extremely expensive. New antibody treatments in development can be divided into anti-cytokine agents, cell-targeted therapies, co-stimulation inhibitors, and treatments aimed at preventing joint erosion consequent on inflammation. This review discusses the state of the art in the development of these agents for management of this common group of diseases.
Inhibitors of TACE and Caspase-1 As Anti-inflammatory Drugs
Authors: Le Giang T. , Abbenante Giovanni
Published: October 2005

TNF-α neutralising agents such as Infliximab (Remicade®), Etanercept (Enbrel®) and the IL-1 receptor antagonist Anakinra (Kineret®), are currently used clinically for the treatment of many inflammatory diseases such as Crohns disease, rheumatoid arthritis, ankylosing spondylitis, juvenile rheumatoid arthritis, psoriatic arthritis and psoriasis. These protein preparations are expensive to manufacture and administer, need to be injected and can cause allergic reactions. An alternative approach to lowering the levels of TNF-α and IL- 1β in inflammatory disease, is to inhibit the enzymes that generate these cytokines using cheaper small molecules. This paper is a broad overview of the progress that has been achieved so far, with respect to small molecule inhibitor design and pharmacological studies (in animals and humans), for the metalloprotease Tumour Necrosis Factor-α Converting Enzyme (TACE) and the cysteine protease Caspase-1 (Interleukin-1β Converting Enzyme, ICE). Inhibitors of these two enzymes are currently considered to be good therapeutic targets that have the potential to provide relatively inexpensive and orally bioavailable anti-inflammatory agents in the future.
Drugs To Treat Inflammation: A Historical Introduction
Authors: Whitehouse Michael W.
Published: October 2005

Drugs to treat inflammation are discussed under the following headings: (1) random discoveries covering copper, salicylates, heterocyclic diones, ACTH, adrenal steroids and disease-modifying agents (DMARDs); these include Au(I)-thiolates, chloroquine, and hydroxychloroquine, minocycline, cyclosporin, salazopyrine, D-penicillamine and methotrexate; (2) programmed NSAID developments covering salicylates and fenamates, arylalkanoates, diones, non-acidic NSAIDs, clozic, lobenzarit and coxibs; (3) synthetic glucocorticosteroids; and (4) Biologicals for neutralising pro-inflammatory cytokines. Clinical problems are highlighted, particularly unacceptable side-effects affecting the GI tract, skin, liver, etc. that caused many drugs to be withdrawn. Drug combinations may overcome some of these problems. The bibliography has selected reviews and monographs covering 50 years of publications.
Nonpeptide Ligands That Target Peptide-Activated GPCRs In Inflammation
Authors: Blakeney Jade S. , Fairlie David P.
Published: October 2005

The focus of this review is on G protein-coupled receptors (GPCRs) for which nonpeptidic ligands are known and have been evaluated for the treatment of inflammatory conditions. GPCRs are the most prevalent class of cell surface proteins in pharmaceutical research today, and GPCR-targeting drugs account for one tenth of worldwide pharmaceutical sales. Of over 800 human GPCRs identified to date, several hundred are activated by peptides/proteins and just over 30 of these have been identified so far as potential therapeutic targets for the treatment of inflammatory diseases. This review highlights those GPCRs and over 60 structurally diverse nonpeptidic compounds that interact with them and display pro- or anti- inflammatory properties. Among these GPCR targets are the receptors for peptides like bradykinin, chemokines, complement anaphylatoxins, corticotropin releasing factor, endothelins, melanocortins, tachykinins, urocortins, as well as the protease activated receptors (PARs). Other peptide activated GPCRs implicated in inflammation, like those that bind angiotensin II, N-formyl peptides, galanin, neuropeptide Y, opioids and oxytocin, are only briefly discussed because there is either less direct association with inflammation or few/no nonpeptidic antiinflammatory ligands known. While it is still very early in the development of antiinflammatory drugs that target GPCRs, there is already a wealth of information supporting their important roles as cellular sentries in inflammatory diseases. New opportunities are emerging to evaluate antiinflammatory activities of potent and selective GPCR-binding ligands, including those being developed for other disease indications. In summary, GPCRs deserve a great deal more attention as potential therapeutic targets in inflammatory diseases.
Therapeutic Targets in Inflammatory Disease
Authors: Hume David A. , Fairlie David P.
Published: October 2005

This commentary is an introduction to a special issue on "Latest Developments in the Treatment of Inflammation". It outlines some key events in the inflammatory response to infection or injury and describes some of the important drug targets of relevance to the succeeding articles, which survey inhibitors of these targets as prospective or current antiinflammatory drugs. It also highlights important limitations in the validation of inflammatory drug targets, and in the rate of discovery and development of new antiinflammatory drugs.
Structure/Function Overview of Proteins Involved in Iron Storage and Transport
Authors: Sargent Peter J. , Farnaud Sebastien , Evans Robert W.
Published: October 2005

Iron, the major trace element in the body, is an essential component of many proteins and enzymes. As low-molecular-weight iron is potentially toxic to cells, higher organisms express a number of proteins for the transport and storage of iron. We review our current understanding of the intestinal absorption of iron in the light of recently identified membrane proteins, namely the ferrric reductase, Dcytb, the two iron(II) transport proteins, DMT1 and ferroportin/Ireg1, and hephaestin, the membrane-bound homologue of the ferroxidase ceruloplasmin. Two types of mammalian transferrin receptor, TfR1 and TfR2, are now known to exist. The structure of TfR1 and its role in the process of receptor-mediated cellular uptake of iron are presented together with structural information on the iron storage protein ferritin. Mechanisms for the regulation of levels of TfR1 and ferritin, as well as other proteins involved in iron homeostasis, are discussed. Our current knowledge and understanding of the structure of members of the transferrin family of iron-binding proteins and the nature of the iron-binding centres in transferrins is presented, together with information on the processes of iron-uptake and iron-release by transferrin and a summary of the elements that have been found to bind to transferrins.
Molecular Mechanisms of Iron Uptake by Cells and the Use of Iron Chelators for the Treatment of Cancer
Authors: Richardson Des R.
Published: October 2005

The field of iron (Fe) metabolism has been invigorated in the past 10 years with the discovery of a variety of new molecules involved in the homeostatic control of this critical nutrient. These proteins include the transferrin receptor 2, frataxin, hephaestin, hepcidin, hemojuvelin and others. Basic understanding of the metabolism of Fe in cells is vital in order to develop Fe chelators for the treatment of a variety of disease states. In addition, examination of the role of Fe in the regulation of cell cycle progression and angiogenesis has led to investigations of the use of novel Fe chelators as anti-proliferative agents. These studies have resulted in the identification of new ligands that show selective and potent anti-tumor activity in vitro and in vivo. Moreover, the ability of these chelators to inhibit growth is not only limited to the inhibition of DNA synthesis. In fact, there is a range of targets that are affected by Fe-depletion, such as molecules involved in cell cycle control, angiogenesis and metastasis suppression. These include hypoxia-inducible factor-1α (HIF-1a), vascular endothelial growth factor-1 (VEGF1), p21CIP1/WAF1, cyclin D1 and the protein product of the N-myc downstream regulated gene-1 (Ndrg1). As such, Fe chelators can now be designed to target molecules to induce specific effects, for instance, angiogenesis or metastasis suppression.
Advances in Iron Overload Therapies. Prospects for Effective Use of Deferiprone (L1), Deferoxamine, the New Experimental Chelators ICL670, GT56-252, L1NAll and their Combinations
Authors: Kontoghiorghes George J. , Eracleous Eleni , Economides Charalambos , Kolnagou Annita
Published: October 2005

Effective new therapies and mechanisms have been developed for the targeting and prevention of iron overload and toxicity in thalassaemia and idiopathic haemochromatosis patients. A new era in the development of chelating drugs began with the introduction of deferiprone or L1, which as a monotherapy or in combination with deferoxamine can be used universally for effective chelation treatments, rapid iron removal, maintenance of low iron stores and prevention of heart and other organ damage caused by iron overload. Several experimental iron chelators such as deferasirox (4-[3,5-bis (2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid) or ICL670, deferitrin (4,5-dihydro-2- (2,4-dihydroxyphenyl)-4-methylthiazole-4 (S)-carboxylic acid) or GT56- 252, 1-allyl-2-methyl-3-hydroxypyrid-4-one or L1NAll and starch deferoxamine polymers have reached different stages of clinical development. The lipophilic ICL670, which can only be administered once daily is generally ineffective in causing negative iron balance but is effective in reducing liver iron. It is suspected that it may increase iron absorption and the redistribution of iron from the liver to the heart and other organs. The experimental iron chelators do not appear to have significant advantages in efficacy and toxicity by comparison to deferiprone, deferoxamine or their combination. However, the prospect of combination therapies using deferiprone, deferoxamine and new chelators will provide new mechanisms of chelator interactions, which may lead to higher efficacy and lower toxicity by comparison to monotherapies. A major disadvantage of the experimental chelators is that even if they are approved for clinical use, they are unlikely to be as inexpensive as deferiprone and become available to the vast majority of thalassaemia patients, who live in developing countries.
Chelating Agents Used for Plutonium and Uranium Removal in Radiation Emergency Medicine
Authors: Fukuda Satoshi
Published: October 2005

The prospects of using chelating agents for increasing the excretion of actinides are reviewed. The removal of plutonium by chelating agents is of great importance because plutonium is extremely dangerous and induces cancer due to radiation toxicity. Similarly, uranium is a radionuclide, which causes severe renal dysfunction within a short time period due to chemical toxicity. It may also induce cancers such as leukemia and osteosarcoma in cases of long-term internal radiation exposure. Investigations on chelating agents for the removal of plutonium were initiated in the 1960s and 1970s. Diethylenetriaminepentaacetic acid (DTPA) is recognized as a chelating agent that accelerates the excretion of plutonium in early treatment after an accident. Thereafter, there has long been an interest in finding new chelating agents with radionuclide removal properties for use in therapy, and many chelating agents such as 3,4,3-LIHOPO and CBMIDA have been studied for their ability to remove plutonium and uranium. Recently, the focus has turned to drugs that have been used successfully in the treatment of a variety of other diseases, for example the iron chelating drug deferiprone or 1,2-dimethyl-3-hydroxypyrid-4-one (L1), which is used in thalassaemia and ethane-1-hydroxy-1,1- bisphosphonate (EHBP), which is used in osteoporosis. Within this context, it is important to examine the clinical use of these two drugs as well as the properties of the experimental chelators 3,4,3-LIHOPO and CBMIDA in order to identify possible uses in the treatment of radiation workers contaminated with plutonium and uranium.
Impact assessment of oncology literature published in Serbia
Authors: Baltic Vladimir
Published: October 2005

BACKGROUND: The study evaluates publication and distribution of biomedical and oncology articles in medical journals in Serbia from 1995 to 2000 and their correlation with socioeconomic variables. METHODS: Retrospective bibliometric research was done in the following medical journals: Srpski Arhiv, Vojnosanitetski Pregled, Medicinski Pregled, and Archive of Oncology. RESULTS: Quantitative analysis showed that 2,468 biomedical articles were published in Serbia. Out of these 855 (30.64%) were oncology papers, which accounts for 3.6% of oncology article production in the countries of European Union. The number of oncology articles in relation to the number of inhabitants was 0.00024%, and 0.10% in relation to GDP. The analysis of key words showed that breast cancer was the leading field of research. Adryamicin was the most frequently drug used in clinical trials and apoptosis was the most investigated topic of experimental research. Standardization of key words according to MeSH was highly recommended. CONCLUSION: Bibliometric analysis shows that the production of scientific oncology literature in Serbia has been very low in comparison with the same production in small and large countries of European Union. The assessment and the quality of the oncology and biomedical publications have an effect on the definition of the position and development of the strategy for scientific production in the country. Systematization of the national database for biomedical publications will help the assessment of the quality of scientific research in oncology and medicine in general.
Bioinformatic tools for cancer geneticists
Authors: Stankov Karmen
Published: October 2005

Early detection is essential for the control and prevention of many diseases, particularly cancer, which is the reason why the need for new disease markers with improved sensitivity and specificity continues to grow. Utilization of sophisticated bioinformatic tools enables the increased specificity and a relatively large quantity of high quality assays for any gene of interest. Understanding the molecular characteristics of diseases, such as cancer and the detection of mutations or changes in gene expression patterns that occur as a result of the disease, will bring researchers one step closer to achieving the predictive power needed for the development of new therapies, the design of clinical trials, and specific patient treatment planning. Genetic screening is one of the fastest moving areas of medical science, particularly in oncology, and as more genes are cloned, and more disease-associated mutations discovered, the workload is set to increase considerably with the utilization of bioinformatics tools used in integration and analysis of genomic, proteomic and metabolomic profiles of cancer. .
The voice of patients with laryngeal carcinoma after oncosurgery
Authors: Mitrovic Slobodan , Jovancevic Ljiljana
Published: October 2005

The voice of patients indicated for surgical procedures in treating of dysphonia is already damaged before the operation. The problem, which exists at the level of glottis patients usually try to solve by compensative mechanisms. The quality of voice after the interventions in larynx depends on the type and width of resection, disturbance of physiological phonation mechanisms, and ability to establish optimal phonation automatism. The damage of laryngeal structure, especially its glottic part and vocal cords as its central part, no matter if they are just fibrous or they are partially or totally absent, leads into the development of substitutive phonation mechanisms. The most frequent substitutive mechanisms are: vestibular, ventricular, and chordoventricular phonation. There are some variations of these phonation mechanisms, which are conditioned not only by applied surgical technique, but as they are also individual characteristics, they can be the consequence of applied rehabilitation methods. The diagnosis of voice condition before and after the oncosurgical procedure is done by: laryngostroboscopy, subjective acoustic analysis of voice, and objective acoustic analysis of voice (sonography or computer analysis of acoustic signal). The most of laryngeal carcinomas appear in glottic region, so the function of phonation imposes itself as the objective parameter to measure the quality of life after the oncosurgery of larynx. That is the reason why according to the priority, it is just behind the principle of "oncologic radicalism". Phonation as the most complex laryngeal function seems to have secondary importance. All known operative techniques, especially partial resections, have the preservation of phonation as their goal.
Curing characteristics of chlorosulphonated polyethylene and natural rubber blends
Authors: Markovic Gordana , Radovanovic Blaga , Budinski-Simendic Jaroslava , Marinovic-Cincovic Milena
Published: October 2005

The dependence of the Mooney scorch time and cure index on the blend ratio of chlorosulphonated polyethylene/natural rubber (CSM/SMR 20 CV) and chlorosulphonated polyethylene/chlorinated natural rubber (CSM/Pergut S 40) blends were determined in the temperature range from 120 oC to 160 oC using a Monsanto Mooney viscometer. Semi-efficient vulcanization systems were used for the study. The morphology of the fracture surface of the crosslinked systems was determined by Scanning Electron Microscopy (SEM). The results showed that the scorch time decreased with increasing SMR 20 CV and Pergut S 40 contents. This observation is attributed to the increasing solubility of sulfur, as the content of SMR 20 CV and Pergut S 40 in the composition increased. For temperatures greater than 140 oC, the dependence of the scorch time on blend ratios diminishes, as enough thermal energy is available to overcome the activation energy of vulcanization. The differing curing characteristics of the two blends is explained by the compatibility factor of the respective blend. Morphological analysis of the blends shows a very satisfactory agreement.
Pereparation and characterization of two types of covalently immobilized amyloglucosidase
Authors: Milosavic Nenad , Prodanovic Radivoje , Jovanovic Slobodan , Novakovic Irena , Vujcic Zoran
Published: October 2005

Amyloglucosidase from A. niger was covalently immobilized onto poly( GMA-co-EGDMA) by the glutaraldehyde and periodate method. The immobilization of amyloglucosidase after periodate oxidation gave a preparate with the highest specific activity reported so far on similar polymers. The obtained immobilized preparates show the same pH optimum, but a higher temperature optimum compared with the soluble enzyme. The kinetic parameters for the hydrolysis of soluble starch by free and both immobilized enzymes were determined. .
Voltammetric determination of imidacloprid and thiamethoxam
Authors: Guzsvány Valeria , Gaál Ferenc , Bjelica Luka , Ökrész Silvija
Published: October 2005

A simple voltammetric method using a glassy carbon working electrode was developed for the determination of two members from the neonicotinoid group of insecticides: imidacloprid and thiamethoxam. The experiments showed that the voltammetric response depends on the mode of electrode surface pretreatment and the polarization mode. The response appeared to be linear in the range from 0.028 to 0.50 mg/cm3 for both analyses. The limit of detection was 0.0077 mg/cm3 for imidacloprid and 0.0085 mg/cm3 for thiamethoxam, the limit of quantitation was 0.026 mg/cm3 and 0.028 mg/cm3, respectively. The developed method was applied for the determination of these insecticides in potato samples sprayed with Confidor 200-SL or Actara 25-WG as well as commercial formulations of imidacloprid and thiamethoxam. A recovery trial was performed to assess the accuracy of the results, the recovery values being between 95?102 % for both of neonicotinoids.
Electrocatalysis of a SiC particle-modified glassy carbon electrode for the oxidation of adrenaline in a KRPB physiological solution
Authors: Yu Zhang-Yu , Kong De-Sheng , Wu Shu-Xin , Wang Lei , Wang Hanf-Qing
Published: October 2005

The electrocatalytic properties of a SiC particle-modified glassy carbon electrode (MGC) for adrenaline oxidation were studied by cyclic voltammetry, double-potential step chronoculometry and electrochemical impedance spectroscopy in a pH 7.4 physiological Kres?Ringer phosphate buffer (KRPB) solution. It was shown that modification of the electrode with SiC particles has a marked electrocatalytic effect on the electrochemical reaction of adrenaline, i.e., the activity and the reversibility of the MGC electrode were significantly improved compared to an unmodified electrode. This was attributed to the adsorption effect of the electroactive adrenaline molecules on the MGC electrode surface. .
Determination of quercetin in pharmaceutical formulations via its reaction with potassium-titanyloxalate: Determination of the stability constants of the quercetin-titanyloxalato complex
Authors: Kuntic Vesna , Pejic Natasa , Micic Svetlana , Vukojevic Vladana , Vujic Zorica , Malesev Dusan
Published: October 2005

Asimple, rapid and accurate procedure for the quantitative determination of quercetin in its pure form and in formulations has been developed. The method is based on the spectrophotometric determination of a complex formed between quercetin and potassium titanyloxalate in 50 % ethanolic solutions. To characterize the quercetin titanyloxalato complex, the stability constants of the complex were determinated potentiometrically and spectrophotometrically at different temperatures (T = 26.0oC, 34oC and 39.0oC), as well as at different ionic strengths (I = 5.0x10-4 mol dm-3, 3.0x10-2 mol dm-3 and 6.0x10-2 mol dm-3) and the thermodynamic parameters were calculated. As quercetin is usually conjugated to vitamin C in pharmaceutical formulations, two procedures for the quantitative determination of quercetin by this complexing reaction were tested - both in the absence and presence of ascorbic acid. In both procedures, the Beer law was obeyed over the same concentration range of quercetin, i.e., 0.85 ?g mL-1 - 16.9 ?g mL-1. In the first procedure in the absence of ascorbic acid the molar absorptivity coefficient of the quercetin-titanyloxalate complex is a=2.49 x 104 mol-1 dm3 cm-1, Sandells sensitivity of the method is S = 1.35 x 10-2 ?g cm-2 and the detection limit is d = 0.67 ?g mL-1. Whereas, in the presence of ascorbic acid (second procedure) a = 3.04 x 104 mol-1 dm3 cm-1, S = 1.11 x 10-2 ?g mL-1. The proposed method was verified for the determination of quercetin in pharmaceutical dosage forms. .
Synthesis of thiourea derivatives bearing the benzo[b]thiophene nucleus as potential antimicrobial agents
Authors: Thakar K.M. , Paghdar D.J. , Chovatia P.T. , Joshi H.S.
Published: October 2005

The synthesis of a group of thiohydantoins and thiobarbiturates derived from 2-N-arylthiopyridocarbonyl-3,5-dichlorobenzo[b]thiophene is described. The structures of the new compounds are supported by IR, 1H-NMR and mass spectral data. These compounds were tested in vitro for their antimicrobial activities.
Expression and purification of the Sgm protein from E. coli
Authors: Ilic-Tomic Tatjana , Markovic Sandra , Vasiljevic Branka
Published: October 2005

The Sgm gene from Micromonospora zionensis, the producer of the aminoglycoside antibiotic G-52, encodes for Sgmmethylasewhich modifies the target site on 16S rRNAand thus protects the producer against its own toxic product. The sgm gene wasmodified by polymerase chain reaction (PCR) and cloned in the QIA express pQE-30 vector in order to make a construct that places the (His)6 tag at the N-terminus of the protein. The resulting expression construct was transformed in the E. coli strain NM522 and the functional activity of the Sgm-His fusion protein was confirmed in vivo. Purification of the (His)6-tagged Sgm protein by Ni-NTA affinity chromatography was performed under native conditions and the protein was detected on a sodium dodecyl sulfate polyacrylamide gel. Sgm methylase was purified to homogeneity > 95 %. Polyclonal antibodies raised to purified (His)6-tagged Sgm protein were used to identify this protein by Western blot analysis.
AFM studies of DNA structures extracted from adriamycin treated and non-treated Erlich tumor cells
Authors: Avramov-Ivic M. , Petrovic Slobodan , Kalman E. , Milosavljevic T. , Reljin I. , Reljin B. , Bogdanovic G. , Baltic Vit.V. , Keresztes Z.
Published: October 2005

Atomic force microscopy (AFM), a unique tool to investigate drug treatment of cancer cells, was used to analyze the anti-neoplastic activity of adriamycin by comparing DNA structures of non-treated and adriamycin-treated Ehrlich tumor cells. The non-treated cells exhibited a highly branched intact chromatin structure, related to the intensive DNA replication in cancer cells. Images from adriamycin-treated tumor cells showed that the DNA chains were broken and the chromatin structure had been destroyed. Possible explanations for these effects of adriamycin are considered: breakage of hydrogen bonding, oxidation and intercalation effects, as well as the poisoning of topoisomerase enzyme. DNA fractal and multifractal analyses performed in order to evaluate the degree of bond scission, showed that the treated DNA had become more fractal compared to non-treated DNA.
Electrodeposition and characterization of Fe–Mo alloys as cathodes for hydrogen evolution in the process of chlorate production
Authors: Grgur Branimir , Krstajic Nedeljko , Elezovic Nevenka , Jovic Vladimir
Published: October 2005

Fe?Mo alloys were electrodeposited from a pyrophosphate bath using a single diode rectified AC current. Their composition and morphology were investigated by SEM, optical microscopy and EDS, in order to determine the influence of the deposition conditions on the morphology and composition of these alloys. It was shown that the electrodeposition parameters, such as chemical bath composition and current density, influenced both the composition of the Fe?Mo alloys and the current efficiency for their deposition, while the micro and macro-morphology did not change significantly with changing conditions of alloy electrodeposition. It was found that the electrodeposited Fe?Mo alloys possessed a 0.15 V to 0.30 V lower overvoltage than mild steel for hydrogen evolution in an electrolyte commonly used in commercial chlorate production, depending on the alloy composition, i.e., the conditions of alloy electrodeposition.
Optimization of the determination of deoxynivalenol in corn samples by liquid chromatography and a comparison of two clean-up principles
Authors: Abramovic Biljana , Jajic Igor , Juric Verica , Gaál Ferenc
Published: October 2005

The determination of deoxynivalenol (DON) in corn by liquid chromatography with DAD detection was optimized. The separations were achieved on a Hypersil ODS column (100 x 4.6 mm; particle size 5 ?m) by isocratic elution (0.6 cm3/min), a mobile phase consisting of acetonitrile?water in the ratio of 16:84. UV Detection was performed at 220 nm. Linear calibration curves were constructed in the concentration range of 0.72 ? 12.00 ng/?l (equivalent to 0.29 ? 4.8 ?g/g com). The detection limit measured as the signal-to-noise ratio (3:1) was 0.16 ng/?l for DON (equivalent to 0.06 ?g/g corn). The efficiencies of two clean-up principles for crude corn extract were compared solid-phase and immunochemical extraction. The efficiency of solid-phase extraction was found to be higher, with a value of 92.7 % when MycoSep 225 columns were used, while its value was 97.6 % when self-made activated charcoal?alumina?Celite?cationic columns were used. In contrast, the efficiency of the immunochemical columns (IMA) was only 73.8%. It was also found that the self-made columns could be used at least three times in a row in that way differing from the MycoSep 225 columns, which could not be reused either with or without regeneration, as well as from the IMA columns, which had a regeneration efficiency of 53.6 %.
SnCl4 induced formation of C3-C11 alkenyl galactopyranosides as precursors for unsaturated neutral bolaforms
Authors: Konstantinovic Stanimir , Dimitrijevic Biljana , Teodorovic Aleksandar , Gojkovic Svetislav , Pavlovic Vladimir , Radulovic Veselin
Published: October 2005

The SnCl4 catalyzed glycosylation reaction of peracetylated ?-D-derivatives with terminally unsaturated C3?C11 alkenols was used for the synthesis of some C3?C11 alkenyl ?-D-galactopyranosides, as precursors for unsaturated neutral bolaforms.
Synthesis and characterization of novel substituted spiro[isobenzofuran-1(3H), 9’-xanthene]-3-ones
Authors: Patel Sachin.V. , Patel Manish , Patel Rangan
Published: October 2005

The ketoacid, 2-(4-diethylamino-2-hydroxybenzoyl)benzoic acid, prepared from N,N-diethyl-m-aminophenol and phthalic anhydride, was reacted with various substituted 3-[6-methoxybenzothiazol-2-yl]-4(3H)-quinazolinones in the presence of a dehydration condensing agent to afford novel spiro[isobenzofuran-1(3H),9?-xanthene]-3-ones. The benzothiazolyl quinazolinones were synthesized by reacting 2-amino-6-methoxybenzothiazole with various substituted benzoxazinones. All compounds were characterized by melting point determination, elemental analysis, infra- red spectroscopy NMR-spectroscopy and UV-visible sprectroscopy. All the fluoran compounds are colourless or nearly colourless and produce colour in the presence of acidic media.
Isolation and synthesis of anthraquinones and related compounds of Rubia cordifolia
Authors: Singh Ram , Geetanjali G
Published: October 2005

Anthraquinones and their glycosides, along with other compounds, have been isolated and characterized from the acetone:water (1:1) percolation of dried roots of Rubia cordifolia. Selected anthraquinones were synthesized using montmorillonite clays under solventless condition in 75 to 85 % yield.
Molecular-orbital and structural descriptors in theoretical investigation of electroreduction of nitrodiazoles
Authors: Kolaric Branko , Juranic Ivan , Dumanovic Dragica
Published: October 2005

It is shown how a simple theoretical approach can be used for the investigation of electro-organic reactions.Mononitroimidazoles and mononitropyrazoles were studied by the semiempirical MNDO-PM3 molecular orbital method. The electrochemical reduction potentials of diazoles have been correlated with the energy of the lowest unoccupied molecular orbital (LUMO). It was found that an admirable correlation could be obtained by the introduction of simple structural descriptors as a correction to the energy of the LUMO. The interaction of a molecule with its surrounding depends on electrostatic potential and on steric hindrance. Most of these steric effects are taken into account using two parameters having a very limited set of integer values. The first (?) is the position of a ring substituent regarding ring nitrogens, which accounts for the different orientations of dipole moments and for the different shape of the electrostatic potential. The second (structural) parameter (?) is the type of the ring, which accounts mostly for different modes of electrode approach, and for different charge polarization patterns in two diazole rings. The extended correlation with ELUMO, ? and ?, is very good, having a regression coefficient r = 0.991. The intrinsic importance of ? and ? is exemplified by their high statistical weight.
High temperature sorption separation of air for producing oxygen‐enriched CO2 stream
Authors: Yang Qing , Lin Y. S. , Bülow Martin
Published: October 2005

A new high temperature sorption process for production of oxygen‐enriched carbon dioxide stream through air separation with carbon dioxide as the purge gas is reported. The process is based on a fixed‐bed packed with a perovskite‐type strontium‐iron doped lanthanum cobaltite, as the sorbent, operated in 500–900°C. Oxygen is adsorbed by the perovskite‐type sorbent with air being fed. An oxygen‐enriched carbon dioxide stream is obtained when the fixed‐bed is regenerated with carbon dioxide as the desorption gas. A specific carbonation‐reaction mechanism for the O2‐desorption process and a complete reverse reaction during the O2‐sorption process are identified with the evidences of XRD and TGA analysis. A study of the sorption process kinetics over a temperature range of 600–800°C was conducted by fixed‐bed sorption/desorption and TGA experiments. Both desorption and sorption processes exhibit a high reaction rate in an initial stage followed by a slower rate in a second stage. A remarkable separation efficiency was observed at 800°C. The new process offers potential for applications in a number of processes including in the efficient and environmentally benign oxyfuel coal combustion process for power generation. © 2005 American Institute of Chemical Engineers AIChE J, 2006
A comparative study on aldol‐type condensation reactions of cyclic, acyclic and substituted cyclic ketones by the W(CO)6/CCl4/UV system
Authors: Altıntaş B. , Bozkurt Ç.
Published: October 2005

Aldol‐type condensation reactions of a number of cyclic, acyclic and substituted cyclic ketones were investigated using the W(CO)6/CCl4/UV system. The progress of the reactions was followed by IR and GC‐MS techniques. The cyclic ketone derivatives with β‐ and γ‐substituent gave the expected condensation products. However, the α‐substituted cyclic, acyclic and unsubstituted cyclic ketones with rings larger than six did not. Formation of [W]–ketone complexes with all of the ketones used was observed by FTIR. With respect to our studies, a mechanism involving an intermediate seven‐coordinate tungsten complex has been proposed. Copyright © 2005 John Wiley & Sons, Ltd.
Assessment of the conformational features of vasoactive intestinal peptide in solution by limited proteolysis experiments
Authors: Stiuso Paola , Marabotti Anna , Facchiano Angelo , Lepretti Marilena , Dicitore Alessandra , Ferranti Pasquale , Cartenì Maria
Published: October 2005

The structural features of vasoactive intestinal peptide (VIP) and of its Gln16‐diaminopropane derivative (VIP‐DAP) in solution were investigated by limited proteolysis experiments with trypsin and thermolysin. The proteolysis of the native peptide by both proteinases takes place near the residues in positions 12 and 21/22, suggesting that these amino acids are embedded in segments more flexible than the rest of the molecule. VIP‐DAP appears to be more resistant to the proteolytic attack of trypsin, indicating that the derivatization in position 16 is able to stabilize the structure of the peptide. Moreover, the analysis of the mass spectra of the proteolytic mixtures supports the evidence that the derivatization is also able to protect Met17 against oxidation. From these data it can be concluded that VIP in solution under physiological conditions is characterized by the presence of segments with secondary structure, linked together by “hinge” regions that confer flexibility to the peptide, whereas VIP‐DAP is embedded in a more rigid conformation, more suitable to receptor interaction. © 2005 Wiley Periodicals, Inc. Biopolymers 81: 110–119, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Synthesis and Proinflammatory Properties of Muramyl Tripeptides Containing Lysine and Diaminopimelic Acid Moieties
Authors: Roychowdhury Abhijit , Wolfert Margreet A. , Boons Geert‐Jan
Published: October 2005

The unusual amino acid diaminopimelic acid (DAP) was prepared by cross metathesis of appropriately protected vinyl glycine and allyl glycine derivatives. Catalytic hydrogenation of the cross‐coupling product resulted in reduction of the double bond and the removal of protecting groups. The resulting compounds were appropriately protected for the polymer‐supported and solution‐phase synthesis of muramyl tripeptides 2 and 3, which differ in the amidation of the α‐carboxylic acids of the isoglutamine and DAP moieties. Muramyl dipeptide (1, MDP), the DAP‐containing muramyl tripeptide 3, and the lysine‐containing muramyl tripeptides 4 and 5 induced TNF‐α gene expression without TNF‐α protein production in a human monocytic cell line. The observed block in translation could be removed by co‐incubation with LPS, resulting in an apparent synergistic effect. Compound 2 did not induce TNF‐α gene expression, neither did it exhibit a synergistic effect with LPS; this indicates that amidation of the α‐carboxylic acids of the isoglutamine and DAP moieties results in a loss of biological activity. It is proposed that amidation of α‐carboxylic acids is a strategy that may be used by pathogens to avoid detection by the innate immune system. Furthermore, the pattern recognition receptors Nod1 and Nod2 have been implicated in the possible induction of a synergistic effect of muropeptides with LPS.
An Enantiomeric Nanoscale Architecture Obtained from a Pseudoenantiomeric Aggregate: Covalent Fixation of Helical Chirality Formed in Self‐Assembled Discotic Triazine Triamides by Chiral Amplification
Authors: Ishi‐i Tsutomu , Kuwahara Rempei , Takata Akihiko , Jeong Yeonhwan , Sakurai Kazuo , Mataka Shuntaro
Published: October 2005

Covalent fixation of a chiral helical structure which is created in a self‐assembling system by a chiral‐amplification method based on the sergeants/soldiers principle is reported. Disk‐shaped triazine triamides self‐assembled to form columnar‐type helical aggregates through π‐stacking interactions among the central triphenyltriazine moieties, hydrogen‐bonding interactions among the amide groups, and van der Waals interactions among the alkyl groups in nonpolar solvents such as hexane, octane, toluene, and p‐xylene. When the achiral triazine triamide soldier component is mixed with a tiny amount of the chiral triazine triamide sergeant component, control of the intrinsic supramolecular helicity of the self‐assembled soldier component by the sergeant component leads to chiral amplification and formation of a pseudoenantiomeric aggregate with only one handedness of the helix. The helicity can be preserved by ring‐closing olefin metathesis polymerization mediated by Grubbs catalyst when an achiral component with terminal olefinic groups forms the pseudoenantiomeric aggregate in the presence of a tiny amount of the chiral component without olefinic groups. After polymerization and removal of the chiral component, the polymeric architecture obtained from the achiral soldier component is optically active and thus can be regarded as an enantiomeric object in which the chiral information transferred from the chiral sergeant component is preserved. The nanoscale chiral structure is fixed perfectly, as indicated by CD spectroscopic evidence obtained in a polar THF medium at high temperature and low concentration. AFM and TEM observations show a nanoscale fibrous structure with a diameter of 2–4 nm, which corresponds to the molecular size of the triazine triamide monomer.