bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of phytofiltration technologies in the removal of heavy metals: A review
Authors: Gardea-Torresdey J. L. , de la Rosa G. , Peralta-Videa J. R. 
Published: October 2007

Abstract
Biosorption is a relatively new process that has proven very promising in the removal of contaminants from aqueous effluents. Microorganisms as well as plant- and animal-derived materials have been used as biosorbents by many researchers. Biomaterial immobilization and chemical modification improves the adsorption capacity and stability of biosorbents. Biosorption experiments over Cu(II), Cd(II), Pb(II), Cr(III), and Ni(II) demonstrated that biomass Cu(II) adsorption ranged from 8.09 to 45.9 mg g−1, while Cd(II) and Cr(VI) adsorption ranged from 0.4 to 10.8 mg g−1 and from 1.47 to 119 mg g−1, respectively. Mechanisms involved in the biosorption process include chemisorption, complexation, surface and pore adsorption-complexation, ion exchange, microprecipitation, hydroxide condensation onto the biosurface, and surface adsorption. Chemical modification and spectroscopic studies have shown that cellular components including carboxyl, hydroxyl, sulfate, sulfhydryl, phosphate, amino, amide, imine, and imidazol moieties have metal binding properties and are therefore the functional groups in the biomass. Column studies using support matrices for biomass immobilization such as silica, agar, polyacrilamide, polysulfone, alginates, cellulase, and different cross-linking agents have been performed to improve the biomass adsorption capacity and reusability. In this review, the salient features of plant-derived materials are highlighted as potential phytofiltration sources in the recovery of toxic heavy and precious metals.
Selective control and rate enhancement of reactions involving catalytic reduction of organohalides and reduced form of myoglobulin in microemulsions
Authors: Kamau G. N. , Munge B. 
Published: October 2007

Abstract
Myoglobin (horse heart, Mb) adsorbed on carbon electrodes or in solution at platinum electrodes was used for electrocatalytic reduction of trans-1,2-dibromocyclohexane (DBCH) and trichloroacetic acid (TCA) in a bicontinuous microemulsion, prepared from sodium didodecyl sulfate (SDS) or hexadecyltrimethylammonium bromide (CTAB), tetradecane, pentanol, and water. Carbon electrodes (glassy carbon, GC, and pyrolytic graphite, PG) exhibited adsorption peaks, whereas platinum (Pt) portrayed diffusion-controlled peaks. Electrode reduction of Mb had E0' at −0.179 ± 0.013 V at GC/SDS, −0.189 ± 0.015 at GC/CTAB, and −0.562 ± 0.018 at Pt/SDS and 0.611 ± 0.008 at Pt/CTAB media.Current efficiencies for electrocatalytic reduction of TCA were higher than that for reduction of dibromocyclohexane. For both substrates, dibromocyclohexane and trichhloroacetic acid, a lowering of overpotential of at least 1.3 V was achieved. Overall, the Pt electrode exhibited higher catalytic efficiencies compared to carbon electrodes, suggesting higher surface concentration and unhindered orientation of the substrate on the Pt electrode. For DBCH, catalytic efficiencies decreased with scan rate, at carbon electrodes as expected for homogeneous solutions, whereas an average value of 2.22 ± 0.42 in SDS and 3.29 ± 0.76 in CTAB microemulsion was obtained at Pt electrodes at a scan rate range of 15 to 3000 mVs−1. Pseudo-first-order rate constants (k') for the rate-determining step (rds) involving reaction of organohalides with catalyst had an average value of 41 ±1 M−1 s−1 for reduction of DBCH/SDS and 4.8 ± 1.0 ×102 M−1 s−1 for reduction of TCA/SDS. Moreover, rate constants were higher in CTAB microemulsion, giving values of 1.5 ±0.016 ×102 and 2.75 ±0.67 × 103 M−1 s−1 for DBCH and TCA, respectively. Positive interfacial charge of the microemulsion conduits influenced catalytic reaction of catalyst and the substrate. Under the conditions of the experiment, no hydrogen evolution was observed at Pt electrodes.
Proteomics principles and challenges
Authors: Marko-Varga G. 
Published: October 2007

Abstract
Proteomics studies rely on high-resolving separation techniques whereby the biological complexity can be unraveled. Both gel-based and liquid-phase separation principles are needed in order to mine deeper into the low abundant area of the proteins expressed in human cell samples. The expression levels that can be reached today with proteomics technology are still only reaching part of all proteins present in complex biological samples. The challenge to be met is not an easy task and will, in many aspects, be determined by the speed and success whereby the analytical field can make milestone progress. Examples will be given from our research group on proteomics studies, as well as principles and challenges within this research area.
Potentiometric detection for high-performance liquid chromatography is a reality: Which classes of organic substances are the targets?
Authors: Nagels L. J. 
Published: October 2007

Abstract
Potentiometric detection in high-performance liquid chromatography (HPLC) is shown to be an underexploited technique. The technique can be of great use to less classical potentiometry targets, such as bioorganics, of low as well as of high molecular weight. The understanding of non-faradaic potentiometry is, however, still problematic. Predicting the selectivity and sensitivity of a potentiometric electrode for organic ionizable substances can be done to a certain extent using QSAR methods. Although many new polymer materials and synthetic receptor molecules for organic ionics are being synthesized, few of them are applied in potentiometric membrane coatings. Hydrophilic organics form an interesting target group for these new materials.
Microbially-assisted dissolution of minerals and its use in the mining industry
Authors: Rawlings D. E. 
Published: October 2007

Abstract
Biomining is currently used successfully for the commercial-scale recovery of metals such as copper, cobalt, and gold from their ores. The mechanism of metal extraction is mainly chemistry-driven and is due to the action of a combination of ferric and hydrogen ions, depending on the type of mineral. These ions are produced by the activity of chemolithotrophic microorganisms that use either iron or sulfur as their energy source and grow in highly acidic conditions. Therefore, metal extraction is a combination of chemistry and microbiology. The mixture of organisms present may vary between processes and is highly dependent on the temperature at which mineral oxidation takes place. In general, relatively low-efficiency dump and heap irrigation processes are used for base metal recovery, while the biooxidation of difficult-to-treat gold-bearing arsenopyrite concentrates is carried out in highly aerated stirred-tank reactors. Bioleaching reactions, the debate as to whether the reactions are direct or indirect, the role of microorganisms, and the types of processes by which metals are extracted from their ores are described. In addition, some new processes under development and the challenges that they present are discussed.
Trends and challenges in biochemical sensors for clinical and environmental monitoring
Authors: Andreescu Silvana , Sadik O. A. 
Published: October 2007

Abstract
Biochemical sensors have emerged as a dynamic technique for qualitative and quantitative analysis of different analytes in clinical diagnosis, environmental monitoring, and food and process control. The need for a low-cost, reliable, ultra-sensitive, and rapid sensor continues to grow as the complexity of application areas increases. New biosensing techniques are emerging due to the need for shorter sample preparation protocols. Such novel biosensor designs make field and bed-site clinical testing simpler with substantial decrease in costs per sample throughputs. In this paper, we will review the recent trends and challenges in clinical and environmental biosensors. The review will focus on immunological, nucleic acid, and cell-based clinical and biological sensors. Special emphasis will be placed on the approaches used for immobilization or biological reagents and low-cost electrochemical biosensors. The promising biosensors for rapid diagnosis of cancer or HIV are also discussed.
In situ poly(ethylene imine) coating of hollow fiber membranes used for microdialysis sampling
Authors: Torto N. , Ohlrogge M. , Gorton L. , Van Alstine J. M. , Laurell Thomas , Marko-Varga G. 
Published: October 2007

Abstract
A method for the in situ modification of hollow fiber membranes used as sampling units for microdialysis probes is presented. The method consists of adsorption-coating, high molecular-weight poly(ethylene imine), PEI, onto membranes, already fitted on microdialysis probes. Modification of membranes was designed to specifically explore the so-called Andrade effects and thus enhance the interaction of membranes with enzyme. The performances of polysulfone, polyethersulfone, and polyamide membranes modified with PEI-enzyme complex were evaluated based on the membrane extraction fraction for maltose and maltotriose and membrane morphology as examined by scanning electron microscopy. Of the membranes tested, the PEI-enzyme complex least affected the performance of the polysulfone membranes. Conversion of maltoheptaose to maltotriose and maltose was increased reproducibly (within a 5 % relative standard deviation) by 50 % for modified membranes compared to the native hollow fiber membranes. The results demonstrate the potential to effectively modify membranes already fitted on a microdialysis probe. Such a procedure can be modified and employed to either promote or reduce membrane–protein interaction for hollow fibers used as microdialysis sampling units or other similar membrane applications.
Definitions of terms relating to reactions of polymers and to functional polymeric materials (IUPAC Recommendations 2003)
Authors: Horie K. , Barón Máximo , Fox R. B. , He J. , Hess M. , Kahovec J. , Kitayama T. , Kubisa P. , Maréchal E. , Mormann W. , Stepto R. F. T. , Tabak D. , Vohlídal J. , Wilks E. S. , Work W. J. 
Published: October 2007

Abstract
The document defines the terms most commonly encountered in the field of polymer reactions and functional polymers. The scope has been limited to terms that are specific to polymer systems. The document is organized into three sections. The first defines the terms relating to reactions of polymers. Names of individual chemical reactions are omitted from the document, even in cases where the reactions are important in the field of polymer reactions. The second section defines the terms relating to polymer reactants and reactive polymeric materials. The third section defines the terms describing functional polymeric materials.
Predicting drug metabolism: Concepts and challenges
Authors: Testa B. , Balmat A.-L. , Long Anthony 
Published: October 2007

Abstract
The paper begins with a discussion of the needs and goals of metabolic predictions in early drug research. Major difficulties toward this objective are examined, mainly the various substrate and product selectivities characteristic of drug metabolism. In a second part, we classify and summarize the major in silico methods used to predict drug metabolism. A discrimination is thus made between “local ”and “global ”systems. In the last part of the paper, the program METEOR is presented and evaluated using the published metabolic data of 10 substrates.
Prion protein as a target for therapeutic interventions
Authors: Liberski P. P. 
Published: October 2007

Abstract
Transmissible spongiform encephalopathies (TSEs), currently known as prion diseases, are neurodegenerative disorders of the central nervous system (CNS) caused by an elusive infectious agent called “prion” (proteinaceous infectious particle). These dis orders include: kuru, Creutzfeldt –Jakob disease (CJD) and its variant (vCJD), Gerstmann–Sträussler–Scheinker (GSS) disease and fatal familial insomnia (FFI) in humans, scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) or mad cow disease, and chronic wasting disease (CWD) in cervids. According to the widely accepted “prion hypothesis”, prion is an aggregate of the abnormal isoform of prion protein (PrPSc). Prion protein is a cell-derived glycoprotein (this normal isoform is called PrPc) encoded by a gene on chromosome 20 in humans (PRNP). In familial forms of TSEs, mutations within the ORF of PRNP are linked to the phenotypic expression of the disease. TSEs are important from public health perspective, and “mad cow disease has created the greatest threat to the safety of human food supply in modern times. vCJD threatens the safety of the blood supply worldwide”. Thus, to search for effective therapy is more than an urgent task. In TSEs, aggregates of PrPSc accumulate in the brain in a form of plaques, or synaptic deposits. The conversion of PrPc into PrPSc and subsequent deposits of PrPSc are targets for therapeutic interventions. These include: tricyclic compounds—acridine and phenothiazine derivatives; quinacrine; anti-PrPSc antibodies; dendrimers; polyethylene antibiotics (amphotericin B, MS-8209); pentosan polysulfate; and dextran sulfate. All these compounds are active in many in vitro and in vivo assays, but not proved definitely active in humans. Thus, albeit interesting and promising, the chemotherapy of TSEs is still in the infant phase.
Structural basis for 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor activation
Authors: Johansen T. N. , Greenwood J. R. , Vogensen S. B. , Krogsgaard-Larsen Povl 
Published: October 2007

Abstract
(S)-Glutamic acid (Glu), the major excitatory neurotransmitter in the central nervous system, operates through ionotropic as well as metabotropic receptors and is considered to be involved in a number of degenerative brain diseases that are currently without any satisfactory therapeutic treatment. Until recently, development of selective Glu receptor agonists had mainly been based on structural optimization of naturally occurring lead compounds structurally related to Glu. Crystallization of the agonist binding domain of the GluR2 subunit of the 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor subtype of ionotropic Glu receptors (iGluRs) in the presence or absence of an agonist has provided important information about ligand-receptor interaction mechanisms. The availability of such binding domain crystal structures has formed the basis for rational design of ligands, especially for the AMPA subtypes of iGluRs.
Search for noncompetitive 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid receptor (AMPAR) antagonists: Synthesis, pharmacological properties, and computational studies
Authors: Chimirri A. , De Sarro G. , Quartarone S. , Barreca M. L. , Caruso R. , De Luca L. , Gitto R. 
Published: October 2007

Abstract
The development of new 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor (AMPAR) negative modulators has received considerable interest due to their crucial role in specific neurological diseases. In recent years, our research group has been engaged in the development of new AMPAR ligands and chemical and biological studies of various 2,3-benzodiazepin-4-(thi)ones (CFMs) and their analogous cyclofunctionalized have been reported. Electrophysiological experiments confirmed that their effects are mediated through the AMPAR complex in a selective and noncompetitive fashion. Moreover, we carried out computational studies which suggested the possible binding site for noncompetitive antagonists; we also developed a 3D ligand-based pharmacophore model in order to map common structural features of highly potent compounds. Our hypothesis was successfully used as a frame work for the design of a new class of allosteric modulators containing a tetrahydroisoquinoline skeleton and led to the discovery of a very potent AMPAR antagonist with marked antiepileptic effects.
Neuropeptide mimetics for pain management
Authors: Lipkowski A. W. , Misicka A. , Carr D. B. , Ronsisvalle G. , Kosson Dariusz , Bonney I. Maszczynska 
Published: October 2007

Abstract
The discovery of numerous endogenous neuropeptides that participate in the formation, transmission, modulation, and perception of pain signals offers numerous strategies for the development of new analgesics. Nevertheless, the same research has not yet replaced opioids as the gold standard of pain treatment. Therefore, one possible avenue of drug development may shift interest from searching for receptor-selective opioids to creating an arsenal of drugs that target multiple opioid and non-opioid sites simultaneously. The presented short review focuses on the development of potential analgesic peptidomimetic compounds based upon opioid neuropeptides and substance P.
New endomorphin analogs with mu-agonist and delta-antagonist properties
Authors: Tóth G. , Keresztes A. , Tömböly Cs. , Péter A. , Fülöp F. , Tourwé D. , Navratilova E. , Varga É. , Roeske W. R. , Yamamura H. I. , Szucs M. , Borsodi A. 
Published: October 2007

Abstract
Endomorphins (endomorphin-1,H-Tyr-Pro-Trp-Phe-NH 2 ,endomorphin-2, Tyr-Pro-Phe-Phe-NH2) are potent and selective µ-opioid receptor agonists. In order to improve the affinity and chemical stability of endomorphins, we have designed, synthesized, and characterized novel analogs with unnatural (2 ',6 '-dimethyltyrosine, Dmt) and/or ß-alicyclic amino acids (ACPC and ACHC). Radioligand binding assay indicated that several of the novel analogs exhibit high affinity for both µ-and d-opioid receptors in rat-or mouse-brain membrane preparations. The most promising derivatives—such as Dmt-Pro-Trp/Phe-Phe-NH2, Dmt-(1 S,2R)-ACPC-Phe-Phe-NH2, and Dmt-(1S,2R)-ACHC-Phe-Phe-NH2 )—were characterized in recombinant cell lines expressing human µ-or d-opioid receptors. Interestingly, while these novel peptides were potent opioid agonists in the functional [35S]GTPgammaS binding assays in Chinese hamster ovary cells expressing the µ-opioid receptors, some behaved as antagonist or inverse agonist in the human d-opioid receptor-expressing CHO cells. Since it has previously been demonstrated that the coadministration of d-antagonists with µ-analgesics attenuates the development of analgesic tolerance, introduction of high-affinity d-antagonist properties into the µ-agonist endomorphins is expected to lead to potent analgesics that produce limited tolerance.
Spacer conformation in biologically active molecules
Authors: Karolak-Wojciechowska J. , Fruzinski A. 
Published: October 2007

Abstract
Based on our contemporary studies on the structures of biologically active molecules, we focus our attention on the aliphatic chain and its conformation. That flexible spacer definitely influenced the balanced position of all pharmacophoric points in molecules of biological ligands. The one atomic linker and two or three atomic spacers with one heteroatom X =O, S, CH2, NH have been taken into account. The conformational preferences clearly depend on the heteroatom X. In the discussion, we utilize our own X-ray data, computation chemistry methods, population analysis, and statistical data from the Cambridge Structural Database (CSD).
Discovery of new anti-inflammatory agents
Authors: Fülöp F. , Lázár László , Szakonyi Z. , Pihlavisto M. , Alaranta Sakari , Vainio P. J. , Juhakoski Auni , Marjamäki Anne , Smith D. J. 
Published: October 2007

Abstract
We have synthesized a series of novel hydrazines and hydrazino alcohols that specifically inhibit vascular adhesion protein-1 (VAP-1), a human endothelial cell adhesion molecule with a well documented role in inflammation. VAP-1 is a semicarbazide-sensitive amine oxidase (SSAO), and the enzyme activity has been demonstrated to have a role in VAP-1 function. An indane hydrazino alcohol was able to reduce clinical symptoms of inflammation in experimental arthritis in rodents and has the potential to be a novel anti-inflammatory drug.
NO donors: Focus on furoxan derivatives
Authors: Gasco Alberto , Fruttero Roberta , Sorba G. , Di Stilo Antonella , Calvino R. 
Published: October 2007

Abstract
The article focuses attention on furoxan derivatives (1,2,5 oxadiazole 2-oxides) as NO donors. Possible mechanisms for NO release from these products in physiological solution and in segments of rabbit femoral artery are briefly considered. The in vitro anti aggregatory activities and the in vitro and in vivo vasodilating properties of a number of furoxans are examined with particular reference to involvement of NO in these actions. The use of the furoxan system to design new NO donor/drug hybrids is discussed in connection with the problem of the balance between NO- and drug dependent activities of the resulting structures. Whether other biological activities (as yet, little studied) of furoxans, such as their antiparasite, antimicrobial, and antitumoral effects, are NO dependent, is a matter still to be explored.
Passive and catalytic antibodies and drug delivery
Authors: Blackburn G. Michael , Rickard J. H. , Cesaro-Tadic S. , Lagos D. , Mekhalfia A. , Partridge L. , Plückthun A. 
Published: October 2007

Abstract
Antibodies are one of the most promising components of the biotechnology repertoire for the purpose of drug delivery. On the one hand, they are proven agents for cell-selective delivery of highly toxic agents in a small but expanding number of cases. This technology calls for the covalent attachment of the cytotoxin to a tumor-specific antibody by a linkage that is reversible under appropriate conditions (antibody conjugate therapy, ACT —“passive delivery”). On the other hand, the linker cleavage can be accomplished by a protein catalyst attached to the tumor-specific antibody (“catalytic delivery”). Where the catalyst is an enzyme, this approach is known as antibody-directed enzyme prodrug therapy (ADEPT). Where the transformation is brought about by a catalytic antibody, it has been termed antibody-directed abzyme prodrug therapy (ADAPT). These approaches will be illustrated with emphasis on how their demand for new biotechnology is being realized by structure-based protein engineering.
Virtual combinatorial chemistry and in silico screening: Efficient tools for lead structure discovery?
Authors: Langer Thierry , Wolber G. 
Published: October 2007

Abstract
In this article, an overview of the most common ligand-based in silico screening techniques is given together with an example on the recent successful application of combined use of pharmacophore modeling, database mining, and biological assays. Additionally, a new approach for structure-based high-throughput pharmacophore model generation is presented. The LigandScout program contains an automated method for creating pharmacophore models from experimentally determined structure data, e.g., publicly available from the Brookhaven Protein Databank (PDB). In a first step, known algorithms were implemented and improved to extract small-molecule ligands from the PDB including assignment of hybridization states and bond orders. Second, from the interactions of the interpreted ligands with relevant surrounding amino acids, pharmacophore models reflecting functional interactions like H-bonds or ionic transfer interactions were created. These models can be used for screening molecular databases for similar modes of actions on the one hand, or for screening one single compound for potential side-effects (reversed screening) on the other hand. The implementation was done using the ilib framework, which also formed the basis of the software tool CombiGen, a fragment-based virtual combinatorial library generation program enabling the user to obtain in silico compound collections with high drug-likeness.