bluuebunny/crossref_metadata_2025 huggingface dataset:
Fish Disease and Biosecurity: Attitudes, Beliefs, and Perceptions of Managers and Owners of Commercial Finfish Recirculating Facilities in the United States and Canada
Authors: Delabbio Julie L. , Johnson Gerald R. , Murphy Brian R. , Hallerman Eric , Woart Anthony , McMullin Steve L.
Published: May 2005

In recirculation finfish facilities in the United States and Canada, biosecurity utilization is neither consistent nor uniform. Seeking reasons for this situation, we examined the beliefs, perceptions, and attitudes of managers and owners of such facilities about fish disease and biosecurity utilization. A questionnaire was mailed in the fall of 2001 to the managers and owners of 152 finfish-rearing recirculation facilities in the United States and Canada to gather information on their attitudes, beliefs, and perceptions regarding fish disease and biosecurity. The response rate to the survey was 86%. This paper reports on a subset of the overall responses, the responses of managers and owners who identified their facility as a business operation. Although respondents had a positive attitude towards biosecurity utilization, they had different beliefs about which disease types were of greatest concern for their farm. Respondents also had differing perceptions on the risk of disease transmission associated with different activities on their farms. In addition, respondents had various beliefs about the practicality and effectiveness of different biosecurity measures and why the practice of biosecurity was important to their farms. This study gives quantitative evidence that different fish farmers perceive disease and the practice of biosecurity differently. This study indicates that recognition of the human dimensions element is an important first step in the creation of biosecurity policies, strategies, and procedures that will be readily accepted and implemented and consistently applied by fish farmers on their farms. The findings challenge the heretofore traditionally accepted belief that poor biosecurity practice on a farm is primarily related to lack of knowledge about biosecurity.
Evaluation of Unpurified Cell Culture Supernatant as Template for the Polymerase Chain Reaction (PCR) with Largemouth Bass Virus
Authors: McClenahan Shasta D. , Grizzle John M. , Schneider J. E.
Published: May 2005

Polymerase chain reaction (PCR) has been used to identify largemouth bass virus (LMBV) in cell culture, and this method has included extraction of the sample DNA. To simplify this procedure, we centrifuged the cell culture fluid to remove cellular debris and then used the supernatant directly in the PCR without DNA extraction. For supernatants from cell cultures inoculated with 1:100 dilutions of homogenized swim bladder or pooled spleen and trunk kidney, only 70.0% of the LMBV-positive samples (based on all available evidence) tested positive with this new PCR method. After a 1:500 dilution of these cell culture supernatants, 85% of the failed samples became PCR positive. In contrast, 97.2% of LMBV-positive samples were PCR-positive when undiluted supernatants from subcultivations (cells inoculated with supernatant from cell cultures showing cytopathic effect [CPE]) were used directly in the PCR. Unpurified cell culture fluid supernatant from blind passage samples (cells inoculated with supernatant from CPE-negative cultures) was PCR-positive for 93.8% of the samples that were eventually shown to be LMBV-positive. The use of cell culture supernatant directly in the PCR reduced the cost and time required to identify LMBV isolated in cell culture. Extraction of DNA from cell cultures to obtain template for PCR identification of LMBV was required for only 2% of the LMBV-positive samples.
Molecular Size, pH, Temperature Stability, and Ontogeny of Inhibitor(s) of Infectious Pancreatic Necrosis Virus (IPNV) in Normal Rainbow Trout Serum
Authors: Park Kyoung C. , Reno Paul W.
Published: May 2005

In this study, we investigated the characteristics of inhibitor(s) of infectious pancreatic necrosis virus (IPNV) found in the serum of normal rainbow trout Oncorhynchus mykiss (RTS). The molecular size, stability to pH and temperature, and ontogeny of the inhibitor in trout were studied, and the effect of cations (Ca2+ and Mg2+) on the activity of the inhibitor was tested. The strongest inhibition of virus was obtained at approximately 150 kDa as measured by ultracentrifugation, sieve gel chromatography, and ultrafiltration. The inhibition decreased significantly when RTS was dialyzed or filtered in the absence of divalent cations, but replacement of at least one cation restored activity. Activity was stable at temperatures ranging from 30°C to 50°C, but 55°C completely destroyed the inhibitory capacity of RTS. The inhibitory activity of RTS was not reduced between pH 4 and 10 but was diminished below pH 4 and above pH 10; such activity was not abrogated by proteases. Additionally, pretreatment of RTS with the polysaccharide mannan significantly reduced inhibition. Thus, the serum inhibitor(s) had many characteristics of a lectin. To determine the ontogeny of inhibition, serum samples were taken from normal rainbow trout, beginning at 2 weeks posthatch; consistent inhibition was not obtained until the rainbow trout had reached the age of 23 weeks posthatch.
Methodological Approaches and Opinions of Researchers Involved in the Surgical Implantation of Telemetry Transmitters in Fish
Authors: Wagner Glenn N. , Cooke Steven J.
Published: May 2005

The purpose of the present study was to characterize the surgical methods researchers use to implant telemetry transmitters in fish and obtain their opinions on fish surgical techniques. The majority of respondents (74%) use monofilament suture to close transmitter incisions, mirroring recent findings that monofilament can help reduce tissue inflammation and promote wound healing. An equal number also believe that maintaining sterile equipment between surgeries is important to preserve fish health. Despite the difficulty of maintaining sterile surgical equipment and surgery areas in field conditions, this opinion does coincide with those of veterinarians. Opinions about what component of surgery is the most hazardous for fish were mixed: 37% believed it to be the initial incision, closely followed by wound closure (23%), insertion of the transmitter and its components (22%), and anesthesia and the handling of the fish (18%). A large proportion (73%) of researchers practice at least occasionally to maintain or improve their surgical skills. The fact that approximately 18% of fish surgeons do not practice was a surprise. Although responses regarding any observations between surgical experience/volume and outcome (e.g., survival) were disparate, the majority (69%) of respondents identified this as an important research area. Furthermore, the majority of researchers (62%) believed it was important to use the individual surgeon for each fish as a covariate when analyzing the data obtained during a study involving multiple surgeons. Despite the variety of practices and opinions of fish surgeons, the majority of responses conformed with or promoted the use of surgical techniques that would benefit the health and welfare of fish. This information should help fisheries researchers refine their surgical techniques and assist governing agencies in forming important regulations on laboratory and field surgical procedures.
Comparison of simulators for process and aqueous chemistry modeling
Authors: Lacour Stella , Van Hille Rob P. , Peterson Karen , Lewis Alison E.
Published: May 2005

The capabilities of four commercial simulators to model precipitation processes is discussed via two case studies: copper(II) sulfide and cobalt(II) carbonate precipitation, respectively. Two approaches were adopted in the modeling, using various existing modeling tools or developing simulation models from an independent critical review of the literature. Simulated results were compared with experimental investigations in order to inform and/or refine model predictions. Results were strongly influenced by the nature and the number of thermodynamic data taken into account in the model. The influence of various parameters on controlling metal solubility have been identified and discussed. This study emphasises the importance of selecting comprehensive and reliable thermodynamic data before modeling a process. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Novolac‐based resists
Authors: Hanabata Makoto
Published: May 2005

The performance of novolac–diazonaphthoquinone‐based positive‐working resists is discussed in terms of the molecular weight distributions and microstructures of the novolac resins and the structural variations in the photoactive dissolution inhibitor. Modelling studies leading to recent improvements allosing the delineation of 0.35 μm line and space pattens by ensuring a focal depth of 105 μm are outlined. Consideration is also given to the new problems such as pivotal shift and halation that arise in the application of high‐resolution photolithography using novolac–diazonaphthoquinone resists.
Polymeric silicon‐containing resist materials
Authors: Miller R. D. , Wallraff G. M.
Published: May 2005

Silicon‐containing bilayer and trilayer photoresist technology is reviewed. Multilayer resist processes of this type rely on pattern generation in a thin imaging layer followed by pattern transfer to the thick planarising underlayer by oxygen reactive ion etching (RIE). The review concentrates on materials in which the silicon is an integral part of the polymer and does not specifically address photoresists where silicon is incorporated in a post‐imaging process step (Such as top‐surface‐imaging resists). The review is not exhaustive but emphasizes instead specific examples of representative resist chemistry.
Wet development of polymer resists: A guide to solvent selection
Authors: Cowie J. M. G.
Published: May 2005

The criteria for selecting effective solvent systems for wet development of polymer resist materials are explored. Methods of estimating the polymer–solvent interactions are described, including the use of solubility parameters and the Flory–huggins interaction parameter. Methods of achieving θ‐conditions, which represent minimal solvent–precipitant mixtures, or the more novel approach of establishing cosolvent systems are described. The rate dissolution has also bee identified as a controlling parameter. Some optical and gravimetric methods for measuring dissolution rates for polymer films are outlined. Examples of the influence of these factors on the sensitivity and contrast of resists such as poly(methylmethacrylate) and poly(p‐methyl styrene‐stat‐chloromethyl styrene) are described.
Cerebral metabolism in newborn dogs during reversible asphyxia
Authors: Vannucci Robert C. , Duffy Thomas E.
Published: May 2005

Acute, systemic asphyxia was induced in paralyzed, lightly anesthetized 1‐ to 2‐day‐old dogs by respiratory arrest. Measurements of arterial blood pressure, acid‐base balance, and concentrations of pyruvate, lactate, and glucose in blood were correlated with electroencephalographic activity and with concentrations of high‐energy phosphates and glycolytic substrates in the cerebral cortex. Most animals tolerated 15 minutes, but not 20 minutes, of asphyxia with apparently normal behavioral recovery. Asphyxia was always accompanied by bradycardia, systemic hypotension, and a progressive decline in arterial pH; the concentration of blood lactate and the lactate/pyruvate ratio rose. Blood glucose levels were unaffected, at least during the first 10 minutes. Concentrations of glucose and phosphocreatine in cerebral cortex declined rapidly during asphyxia to low levels, but levels of adenosine triphosphate remained within normal limits for up to 5 minutes despite the fact that electrical activity in brain ceased within 2 minutes. The intravenous injection of carbon black into animals asphyxiated for 21/2, 5, 10, or 15 minutes revealed substantial reductions in blood flow to brain during asphyxia; however, relative to the cerebral cortex, brainstem structures received a preferential blood supply.
Ependymal changes in the human fetal brain
Authors: Dooling Elizabeth C. , Chi Je G. , Gilles Floyd H.
Published: May 2005

Focal ependymal loss, increasing in extent with advancing gestational age, was found in 111 human fetal brains. Its regular occurrence in specific sites, viz, the lateral walls of the lateral ventricles, over sector CA2 of the hippocampus, and on the ventral surface of the corpus callosum and lateral walls of the septum pellucidum, without prominent subependymal gliosis, suggests that restricted ependymal loss may be related to growth and development of the fetal brain. More extensive loss should be considered a marker of a neuropathological process.
Remyelination after transient experimental compression of the spinal cord
Authors: Harrison B. M. , McDonald W. I.
Published: May 2005

The lesion produced in the cat by experimental transient spinal cord compression was examined by electron microscopy. Compression sufficient to produce reversible paraparesis is associated with a predominantly demyelinating lesion; more severe compression produces an increased amount of wallerian degeneration. Remyelination by oligodendrocytes commences in the third week. Complete myelin segments with many normal ultrastructural features are formed. The thickness of the new myelin increases with time but has still not reached adult values after 18 months. Schwann cells of peripheral origin remyelinate some central axons in the more severe lesions.
Visual evoked potentials and quantitative perimetry in multiple sclerosis
Authors: Ellenberger Carl , Ziegler Susan B.
Published: May 2005

The visual evoked potential (VEP) to a flash stimulus proved to be more effective than quantitative perimetry in detecting evidence of previous optic neuritis (97 vs 56%) or asymptomatic lesions in the visual pathways (56 vs 14%) of 49 patients with multiple sclerosis. The characteristic VEP abnormality, increased latency, was also found in 8 of 15 eyes with visual field defects related to ischemic optic neuropathy. This abnormality therefore is not specific for demyelinative disease, but it is highly suggestive in the presence of normal visual function determined psychophysically. The VEP disclosed a high incidence (81%) of asymptomatic lesions in optic nerves opposite previously affected eyes. Neither the presence nor the magnitude of the latency abnormality correlated with the degree of visual impairment. Prolonged latency may not be present at the onset of acute optic neuritis.
Spinal cord involvement by C4–C5 Vertebral subluxation in rheumatoid arthritis: A description of 2 cases examined at necropsy
Authors: Hughes J. Trevor
Published: May 2005

In 2 cases of severe, longstanding rheumatoid arthritis involving the cervical spine, a progressive spinal cord syndrome developed in which spastic paraparesis was combined with a lower motoneuron paresis affecting the upper limbs. In both cases necropsy showed the cause to be subluxation between the C4 and C5 vertebral bodies and backward encroachment into the spinal canal of the upper and posterior part of the C5 vertebral body. A feature of the spinal cord abnormality was central infarction, apparently caused by an effect on a patent anterior spinal artery and manifested not only at the site of spinal cord compression but for several spinal cord segments caudal to this level.
Survival with permanent midbrain dysfunction after surgical treatment of traumatic subdural hematoma: The clinical picture of a duret hemorrhage?
Authors: Caplan L. R. , Zervas N. T.
Published: May 2005

Two patients with severe head trauma, each deeply comatose when initially seen, survived after evacuation of subdural hematoma, administration of corticosteroids and mannitol, and mechanical hyperventilation. Each lived despite persistent bilateral third nerve plasies and pyramidal signs, with relatively well preserved cognitive function. The clinical picture in each case is compatible with the residua of Duret hemorrhages. Useful survival after serious craniocerebral trauma is possible despite midbrain dysfunction.
Rapidly evolving EEG changes in a case of alzheimer disease
Authors: Ehle Albert L. , Johnson Peter C.
Published: May 2005

A patient who presented with a subacutely evolving dementia and electroencephalographic changes resembling those reported in Creutzfeldt‐Jakob disease was found at autopsy to have Alzheimer disease. Despite typical clinical and electroencephalographic findings, accurate discrimination between these two diseases depends on pathological examination.
Grafted syndiotactic polystyrene synthesized via melting graft copolymerization used as a compatibilizer for immiscible syndiotactic polystyrene/polyadimide 66 blends
Authors: Cao Youming , Shen Zhigang , Lin Shang'An
Published: May 2005

A new grafted syndiotactic polystyrene (g‐sPS), to be used as a compatibilizer for syndiotactic polystyrene (sPS)/polyadimide 66 blends, was prepared by the melting graft copolymerization of sPS and monomers composed of itaconic acid and dibutyl maleate with dicumyl peroxide as an initiator. The resulting g‐sPS possessed a side‐chain structure identified by IR spectra, and the results of mechanical testing show that a good impact strength and tensile strength were obtained for g‐sPS at a 7.16‐phr addition of monomer with a 3:1 proportion of dibutyl maleate and itaconic acid. Differential scanning calorimetry and scanning electron microscopy analysis indicated that the g‐sPS maintained a high glass‐transition temperature and a crystalline structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1659–1666, 2005
Morphology development of PBT/PE blends during extrusion and its reflection on the rheological properties
Authors: Hong Joung Sook , Kim Jeong Lim , Ahn Kyung Hyun , Lee Seung Jong
Published: May 2005

In this study, we have investigated morphology evolution of polymer blends during extrusion. By choosing two polymers, high density polyethylene (PE) and poly (1,4‐butylene terephthalate) (PBT), having a large difference in melting temperature, we could control the viscosity ratio of the blend as well as the morphology. The morphology of the dispersed phase evolved from film to fibril and to droplet structure depending on thermal and deformation history. We could maintain the film or fibril structure in a final product by keeping the dispersed phase deformable and rigid enough to avoid the relaxation that is related with instability originating from the interfacial tension. The anisotropic structures (film and fibril) were found to enhance the rheological properties significantly, but in different manners under shear and extensional flow fields. This study shows that diverse morphology can be obtained by controlling processing conditions, and the rheological properties can be dramatically enhanced by morphology control. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1702–1709, 2005
Preparation of poly(methyl methacrylate‐co‐maleic anhydride)/SiO2TiO2 hybrid materials and their thermo‐ and photodegradation behaviors
Authors: Xu Jianwen , Shi Wenfang , Gong Ming , Yu Fei , Yan Lifeng
Published: May 2005

The optically transparent poly(methyl methacrylate‐co‐maleic anhydride) P(MMA‐co‐MA)/SiO2TiO2 hybrid materials were prepared using 3‐aminopropyl triethoxysilane as a coupling agent for organic and inorganic components. Real‐time FTIR was used to monitor the curing process of hybrid sol, indicating that imide group formation decreased with increasing titania content. scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry results confirmed their homogeneous inorganic/organic network structures. TGA analysis showed that incorporated titania greatly prohibits the thermodegradation of hybrid films, especially at the content of 5.3 wt %, showing an increase of about 32.6°C at 5% loss temperature in air. The UV degradation behavior of P(MMA‐co‐MA) studied by quasi‐real‐time FTIR showed that TiO2 incorporated in the hybrid network provides a photocatalytic effect rather than a UV‐shielding effect. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1714–1724, 2005
Fiber diameter of polybutylene terephthalate melt‐blown nonwovens
Authors: Chen Ting , Li Liqing , Huang Xiubao
Published: May 2005

A polymer air‐drawing model of Polybutylene Terephthalate (PBT) melt‐blown nonwovens has been established. The predicted fiber diameter coincides with the experimental data. The effects of the processing parameters on the fiber diameter have been investigated. A lower polymer flow rate, a higher initial air velocity, and a larger die‐to‐collector distance can all produce finer fibers, whereas too high an initial air velocity and too large a die‐to‐collector distance contribute little to the polymer drawing of PBT melt‐blown nonwovens. The results show the great potential of this research for the computer‐assisted design of melt‐blowing technology. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1750–1752, 2005
Web citation data for impact assessment: A comparison of four science disciplines
Authors: Vaughan Liwen , Shaw Debora
Published: May 2005

The number and type of Web citations to journal articles in four areas of science are examined: biology, genetics, medicine, and multidisciplinary sciences. For a sample of 5,972 articles published in 114 journals, the median Web citation counts per journal article range from 6.2 in medicine to 10.4 in genetics. About 30% of Web citations in each area indicate intellectual impact (citations from articles or class readings, in contrast to citations from bibliographic services or the author's or journal's home page). Journals receiving more Web citations also have higher percentages of citations indicating intellectual impact. There is significant correlation between the number of citations reported in the databases from the Institute for Scientific Information (ISI, now Thomson Scientific) and the number of citations retrieved using the Google search engine (Web citations). The correlation is much weaker for journals published outside the United Kingdom or United States and for multidisciplinary journals. Web citation numbers are higher than ISI citation counts, suggesting that Web searches might be conducted for an earlier or a more fine‐grained assessment of an article's impact. The Web‐evident impact of non‐UK/USA publications might provide a balance to the geographic or cultural biases observed in ISI's data, although the stability of Web citation counts is debatable.
Green flavoprotein from P. leiognathi: Purification, characterization and identification as the product of the lux G(N) gene
Authors: Raibekas Andrei A.
Published: May 2005

A green flavoprotein (GFP) was isolated and purified to homogeneity from Photobacterium leiognathi, strain 208. GFP is a homodimer of molecular weight 54000 and contains two molecules of an unusual flavin per molecule of protein. Various biochemical characteristics including isoelectric point, trypsin and chymotrypsin degradation, SDS and temperature influence on subunit dissociation and the dissociation of the flavin chromophore, were investigated. The sequence of 23 N‐terminal amino acids was determined and found to be concurrent with the N‐terminal amino acids was determined and found to be concurrent with the N‐terminal amino acid sequence encoded by the lux G (N) gene of P. leiognathi. This fact suggests that GFP is a structural component of the Photobacterium luminescence system.
Extra‐weak chemiluminescence of drugs. XII. Effect of the molar ratio of amino acid to sugar on extra‐weak chemiluminescence in the Maillard reaction
Authors: Kurosaki Yuichiro , Sato Hideaki , Ishizawa Fumiaki , Mizugaki Michinao
Published: May 2005

The extra‐weak chemiluminescence in the Maillard reaction caused by the reaction between L‐lysine and D‐arabinose was measured, and a linear relationship was found between the chemiluminescence and the amount of L‐lysine added. After a 1‐hour reaction equimolar amounts of D‐arabinose and L‐lysine were consumed regardless of the initial concentration of D‐arabinose. The chemiluminescence of the Maillard reaction originates from Maillard reaction products formed by the equimolar reaction between sugar and amino acid and depends on the concentration of amino acid.
Kinetics of bactericidal activity of antibiotics measured by luciferin‐luciferase assay
Authors: de Rautlin de la Roy Y. , Messedi N. , Grollier G. , Grignon B.
Published: May 2005

ATP production, measured by the luciferin‐luciferase assay, is an indicator of bacterial metabolic activity. This enzymatic assay yields rapid results (< 5 minutes), permitting multiple measurements and establishment of ATP growth curves in order to study the kinetics of antibiotics in bacterial populations. The measurement of free or extracellular ATP, total ATP (extra and intracellular) and the ratio of free to total ATP are additional means of studying the bacteriostatic or bactericidal activity of antibiotics. An increase in free ATP is an indicator of extracellular movement due to alteration of the cell wall. The ratio free ATP/total ATP × 100 ≥ 50%, indicates bacteriallysis. These assays were used to study the effects of 14 antibiotics on two reference strains of Escherichia coli ATCC 25922 and Staphylococcus aureus 25923.
Influence of different luminols on the characteristics of the chemiluminescence reaction in human neutrophils
Authors: Lundqvist Helen , Kricka Larry J. , Stott Richard A. , Thorpe Gary H. G. , Dahlgren Claes
Published: May 2005

In search for a luminol with very high output of light, 20 different luminol samples were tested for their ability to enhance the chemiluminescence reaction in phorbol myristate acetate activated human neutrophils. We found that the majority of luminols tested (17 samples) gave almost the same light output from neutrophils, and that the major part of the activity was from an intracellular origin. Owing to the fact that three isoluminol samples were unable to monitor respiratory burst activity taking place intracellularly, a very low level of chemiluminescence was obtained with these samples. Their light output was, however, greatly increased when horseradish peroxidase or myeloperoxidase was added, showing that the light‐generating reaction with isoluminol as well as with luminol is peroxidase‐dependent.

The fact that isoluminol could also use myeloperoxidase as amplifying peroxidase, suggests that the lack of measurable intracellular activity in the presence of isoluminol is somehow related to a limited or restricted diffusion of the molecule to intracellular sites. The isoluminol system constitutes a sensitive system for measuring release of oxygen metabolites from phagocytic cells.
Reverse micelle‐based chemiluminescence system for quinine sulphate
Authors: Tang Guofeng , Huang Yuming , Shi Wenbing
Published: May 2005

A new chemiluminescence (CL) method is proposed for the determination of quinine sulphate, which is based on the dichloromethane solvent extraction of the ion‐pair complex of tetrachloroaurate (III) with quinine sulphate, and luminol CL detection in a reversed micellar medium formed by the cation surfactant cetyltrimethylammonium bromide in a dichloromethane–cyclohexane (3:7, v[sol ]v)–water (0.35 mol[sol ]L Na2CO3 buffer solution, pH 11.5). The ion‐pair complex of tetrachloroaurate (III) with quinine sulphate produced an analytical CL signal when it entered the reversed micellar water pool. In optimum conditions, CL intensities are proportional to the concentrations of the studied drug over the range 0.015–10 µg[sol ]mL, with a detection limit of 1.5 ng[sol ]mL. The relative standard deviation (RSD) is 1.38% for 2.5 µg[sol ]mL quinine sulphate (n = 11). The method has been applied to the determination of the studied drug in biological fluids, with satisfactory results. Copyright © 2005 John Wiley & Sons, Ltd.
Time‐resolved spectroscopic fluorescence imaging, transient absorption and vibrational spectroscopy of intact and photo‐inhibited photosynthetic tissue
Authors: Lukins Philip B. , Rehman Shakil , Stevens Gregory B. , George Doaa
Published: May 2005

Fluorescence, absorption and vibrational spectroscopic techniques were used to study spinach at the photosystem II (PS II), chloroplast and cellular levels and to determine the effects and mechanisms of ultraviolet‐B (UV‐B) photoinhibition of these structures. Two‐photon fluorescence spectroscopic imaging of intact chloroplasts shows significant spatial variations in the component fluorescence spectra in the range 640–740 nm, indicating that the type and distribution of chlorophylls vary markedly with position in the chloroplast. The chlorophyll distributions and excitonic behaviour in chloroplasts and whole plant tissue were studied using picosecond time‐gated fluorescence imaging, which also showed UV‐induced kinetic changes that clearly indicate that UV‐B induces both structural and excitonic uncoupling of chlorophylls within the light‐harvesting complexes. Transient absorption measurements and low‐frequency infrared and Raman spectroscopy show that the predominant sites of UV‐B damage in PS II are at the oxygen‐evolving centre (OEC) itself, as well as at specific locations near the OEC‐binding sites. Copyright © 2005 John Wiley & Sons, Ltd.
Determination of MDMA and MDA in rat urine by semi‐micro column HPLC‐fluorescence detection with DBD‐F and their monitoring after MDMA administration to rat
Authors: Wada Mitsuhiro , Nakamura Shinichi , Tomita Mamoru , Nakashima Mihoko N. , Nakashima Kenichiro
Published: May 2005

A simultaneous semi‐micro column HPLC method with fluorescence detection of abused drugs, such as 3,4‐methylenedioxymethamphetamine (MDMA), 3,4‐methylenedioxyamphetamine (MDA), amphetamine (AP) and methamphetamine (MP) in rat urine was examined by using 4‐(N,N‐dimethylaminosulphonyl)‐7‐fluoro‐1,2,3‐benzoxadiazole (DBD‐F) as a labelling reagent and α‐phenylethylamine as an internal standard (IS). A sample (50 µL) of rat urine was added to 5 µL IS and 100 µL 100 mmol[sol ]L borate buffer (pH 12) and extracted with 1.5 mL n‐hexane. After evaporation, 50 µL 75 mmol[sol ]L borate buffer (pH 8.5) and 50 µL 20 mmol[sol ]L DBD‐F in CH3CN were added to the residue and mixed well. The resultant solution was heated for 20 min at 80°C and then cooled in an ice bath. A good separation of DBD‐derivatives could be achieved within 45 min using a semi‐micro ODS column with an eluent of CH3CN[sol ]CH3OH[sol ]10 mmol[sol ]L imidazole–HNO3 buffer (pH 7.0) (= 45:5:50, v[sol ]v[sol ]v %). The DBD derivatives were monitored at 565 nm with an excitation at 470 nm. The calibration curves showed good linearity (r = 0.997) with 0.5–15 ng[sol ]mL detection limits at a S[sol ]N ratio of 3. MDMA and MDA in rat urine could be monitored for 15 h after a single administration of MDMA to rat (2.0 mg[sol ]kg, i.p.). The concentrations for MDMA and MDA (n = 3) were 0.13–160.1 and 0.17–10.9 µg[sol ]mL, respectively. Copyright © 2005 John Wiley & Sons, Ltd.
Preliminary electrochemiluminescence study of allantoin in the presence of tris(2,2′‐bipyridine) ruthenium (II)
Authors: Chen Xi , Tao Ying , Zhao Li , Xie Zenghong , Chen Guonan
Published: May 2005

Electrochemiluminescence (ECL) based on allantoin and tris(2,2′‐bipyridine)ruthenium (II) [Ru(bpy)32+] was studied in aqueous alkaline buffer solution (pH 11.0). In a flowing system, the eluted allantoin was mixed with 1.0 mmol[sol ]L Ru(bpy)32+. When the solution passed through a thin layer flow electrolytic cell equipped with a glassy carbon disc electrode (22.1 mm2), both hydroxyl groups of allantoin and Ru(bpy)32+ were oxidized at the potential of +1.50 V (vs. Ag[sol ]AgCl). The luminescence with λmax 610 nm caused by the reaction of electrolytically formed Ru(bpy)32+ with alkoxide radical to generate the excited state of Ru(bpy)32+*. A possible ECL process of allantoin in Ru(bpy)32+ alkaline solution has been discussed. In addition, the factors affecting the ECL response of allantoin are also investigated. Copyright © 2005 John Wiley & Sons, Ltd.
Flow‐injection resonance light scattering detection of proteins at the nanogram level
Authors: Tan Kejun , Li Yuanfang , Huang Chengzhi
Published: May 2005

A resonance light scattering (RLS) detection method for protein was developed, using a flow‐injection system based on the enhancement of RLS signals from Biebrich scarlet (BS) by protein. The enhanced RLS intensities at 286.0 nm, in acidic aqueous medium, were proportional to the protein concentration over the range 0.005–18 µg[sol ]mL and 0.008–16 µg[sol ]mL for human serum albumin (HSA) and bovine serum albumin (BSA), respectively, with corresponding limits of detection (3σ) of 5.00 ng[sol ]mL for HSA, and 7.80 ng[sol ]mL for BSA. The method was successfully applied to the quantification of total proteins in human serum samples. Copyright © 2005 John Wiley & Sons, Ltd.
Method of determining the relative stability of different conformational states of biological macromolecules
Authors: Ptitsyn O. B. , Birshtein T. M.
Published: May 2005

A general approach to the determination of relative stability of any pair of con‐formational states of biological macromolecules or their complexes (in particular, to the determination of relative stability of native and disordered states of the macromolecule) has been suggested. For determining the free energy difference of the two states under the conditions when one of them is considerably more advantageous than the other, it is necessary for the macromolecule to be influenced by the transforming agent which levels free energies of both the conformational states, and to determine the external parameter derivative of the free energy difference in the region of the conformational transition induced by the change in this parameter. If the character of the dependence of this derivative on the external parameter (temperature, solvent composition, etc.) is known, then this allows the determination of the free energy difference of the two states under the conditions considered, even including conditions far from the transition region. The value of the derivative of the free energy difference in the transition region in many cases can be measured directly (in particular, when using calorimetry), while in cases when a direct measurement of the derivative is impossible, it can often he estimated experimentally from the steepness of the conformational transition. The methods of this estimation and also a possible character of the change of the considered derivative during variation of the external parameter are considered for the case when the transforming agent is one of the components of the solvent and, consequently, the derivative of the free energy difference is equal to the difference of number of molecules of this component hound with the macromolecule in two conformational states.
Mechanical properties of poly(glutamic acid) in aqueous solution
Authors: Konno Akira , Kaneko Motozo
Published: May 2005

The interaction between ionizable carboxyl groups and the conformation of poly‐(glutamic acid) (PGA) in aqueous solution were investigated by the mechanical method. The dynamic rigidity of the PGA solution has a maximum value at the pH corresponding to about 50% neutralization point. This may be due to establishing of a maximum attractive force by proton/charge fluctuation between ionizable carboxyl groups at that pH. The dynamic viscosity has a sharp change in the region of pH 5.5–6.5. It is suggested that this behavior is due to the helix–coil transition.
Heats of fusion of various amounts of absorbed water in wool keratin
Authors: Haly A. R. , Snaith J. W.
Published: May 2005

Wool–water systems, at water contents above a threshold value of 22.7 g of water per 100 g of wool keratin, yielded curves of specific heat against temperature showing peaks that are ascribed to the fusion of the absorbed water. Integral and incremental heats of fusion were obtained. Integral heats increase as the square of the water content above the threshold, and incremental heats follow a linear relationship. The incremental heat reaches a value of 55 cal/absorbed water, at the saturation water content, at 0°C of 33.9 g of water per 100 g of keratin. The state of the absorbed water is discussed. Clustering of water molecules takes place only above the threshold water content.
Salt effects on the denaturation of DNA
Authors: Gruenwedel Dieter W. , Hsu Chi‐Hsia
Published: May 2005

When DNA's of differing GC:AT base ratios, e.g. synthetic poly dAT, T4 DNA, calf thymus DNA, E. coli DNA, and M. Iysodeiklicus DNA, are heat‐denatured at, neutral pH in increasing concentrations of Na2SO4 or Cs2SO4 as supporting electrolytes, the variation of melting temperature with average base composition, dTm/dXG C, changes from 45°C (in 0.002M Na) to 11°C (in 4.5M Na) and from 42°C (in 0.002M Cs) to 3°C (in 4.5M Cs). The decrease of dTm/dXG C is a monotonic function of decreasing water activity in the salt, solutions. We interpret this decreased composition dependence of the thermal stability of the various DNA's as being due to a destabilization of the GC base pairs relative to the AT base pairs by the concentrated salt media. A simple quantitative treatment shows that k = sG C/sA T decreases from a value of 4.14 (in 0.01.M Na) to 1.86 (in 3 M Na) and from 4.18 (in 0.01 M Cs) to 1.42 (in 3 M Cs). SA T is the equilibrium constant for the formation of a hydrogen‐bonded AT base pair from a pair of unbonded bases at, the junction between a helical region and a denatured region and sG C is the like constant for the formation of a GC base pair. These results corroborate our previous findings of a strongly reduced composition dependence of the negative logarithm of the methylmercurie hydroxide concentration necessary to produce 50% denaturation when the helix–coil transition of DNA is studied in concentrated Cs2SO4 (ultracentrifugation) instead of in dilute Na2SO4 (ultraviolet spectrophotometry).
Far‐infrared spectra of poly(‐α‐amino acids) with basic alkyl group side chains
Authors: Itoh Koichi , Shimanouchi Takehiko , Oya Masanao
Published: May 2005

Far‐infrared spectra in the region from 700 to 60 cm−1 have been measured for the α‐helix structures of poly(L‐α‐amino‐n‐butyric acid), poly‐L‐norvaline, poly‐L‐norleucine, and poly‐L‐leucine and for the β‐form structures of poly(L‐α‐amino‐n‐butyric acid), poly‐L‐valine, poly(DL‐amino‐n‐butyric acid), poly‐DL‐norvaline, and poly‐DL‐norleucine. The changes of the spectra on N‐deuteration have been measured in the region between 700 and 400 cm−1. It is concluded that, the α‐helix has characteristic bauds near 690, 650, 610, 380, 150, and 100 cm−1, and that the β‐form has characteristic bands near 700, 240, and 120 cm−1. The main‐chain vibrations in the region from 600 to 200 cm−1 are strongly coupled with the side‐chain deformation vibrations.
Interaction des Ions Métalliques avec le DNA. II. Adsorption préférentielle de l'Ion césium par les Acides nucléiques
Authors: Doppler‐Bernardi F. , Daune M.
Published: May 2005

Preferential adsorption of cations occurs in the solvated shell surrounding polyanions, especially polynucleotides and nucleic acids. The solvation parameter Γ is determined from sedimentation coefficients which are considered as pienometric determinations of the specific volume of the sample. By comparing two identical concentrations (0.1M) of monovalent salts, NaCl and CsCl, and using the model of DNA described in the preceding paper, one can relate the ratio SCs/SNa to solvation parameters ΓCs, and ΓNa.On the other hand, Γ can be related to the difference of energy W, between cation and water, to be extracted from the solution and placed in the vicinity of the polyanion. One finds generally a preferential solvation of the polarizable caesium ion by means of London–van der Waals interactions with bases. With reasonable assumptions, an estimate of W can be made, and the predicted value of Γ can be compared to the experimental one. An average of six sites is found around each base in a single‐stranded polymer, but‐only one in the double‐stranded structure. The amount of secondary structure can thus be estimated from the simple measurement of the ratio of two sediment constants.
Studies of a specific association between acriflavine and DNA in intact cells
Authors: Roth Daniel , Manjon Maria L.
Published: May 2005

The nature of a specific association between acriflavine and cellular DNA was investigated by subjecting the DNA of intact cells to denaturation, ultraviolet radiation, and base analog substitution. The predictable modifications of DNA structure were then correlated with the quantitative alterations in dye adsorption by the cells. It was concluded that, under experimental conditions of limited dye availability, the bonding of dye was restricted to sites of highest bonding affinity. These were shown to be situated between adjacent thymine molecules on a single strand of DNA. The 5‐methyl groups of thymine may endow the bond with its specificity.
Concerning the kinetics of polypeptide synthesis on polyribosomes
Authors: MacDonald Carolyn T. , Gibbs Julian H.
Published: May 2005

The kinetics of biosynthesis of polypeptides on polyribosomes is analyzed in accordance with a simple mathematical model. Each ribosome is assumed to block L adjacent. (m‐RNA) template sites but to move a distance of one, and only one, template site (nucleotide triplet) upon the addition of each monomer unit to the growing polypeptide chain bound to it. Solutions are sought, for the probability, nj(t), that a template possesses, at time t, a polypeptide chain that has reached degree of polymerization j.

Several classes of steady‐state solutions are obtained via machine computation. These correspond to various choices of relative rates of initiation, polymerization along templates, and termination (release of completed chains from templates).

Experimental data available from radioactive pulse labeling experiments are discussed. The data obtained by Dintzis, and by Winslow and Ingram, in studies of the synthesis of the α chain of rabbit hemoglobin and human hemoglobin, respectively, are consistent with steady‐state solutions obtained from the current theoretical calculations when the rates of initiation and termination are of comparable magnitude and rate‐determining. In this case, a (relatively) small number of chains are polymerized at a (relatively) fast rate each near the beginning of the template, and there exists a transition to a situation near the end of the template in which a (relatively) large number of chains are polymerized at a (relatively) slow rate each. For this solution the situation near the end of the template is entirely analogous to a traffic jam in automobile traffic.
Influence of temperature on the helix sense of several polyamino acids
Authors: Lotan N. , Momany F. A. , Yan J. F. , Vanderkooi G. , Scheraga H. A.
Published: May 2005

An increase in temperature causes an increase in the amplitudes of intramolecular and intermolecular motions and mainfests itself as an increase in the effective radii of the various atoms, especially hydrogen atoms. If one uses a Lennard‐Jones 6‐12 potential function to account for nonbonded interactions, this increase in the radius of the hydrogen atom is equivalent to a modification of the coefficient of the repulsive part of the Lennard‐Jones potential. Accordingly, this effect of increasing temperature on the helix sense of several polyamino acids is computed by allowing the effective radius of the hydrogen atom to increase. It is found that the preferred sense of several polyamino acid helices changes from right‐ to left‐handed as the temperature is increased. This accounts for recent experimental observations of changes in helix sense with temperature.
Raman spectrum of the right‐handed α‐helix of poly‐L‐alanine
Authors: Koenig J. L. , Sutton P. L.
Published: May 2005

The laser‐excited Raman vibrational spectrum of poly‐L‐alanine has been obtained. The Raman spectrum is compared with the infrared spectrum and vibrational frequencies calculated from normal coordinate analysis. The symmetric modes of the α‐helix appear with strong intensity in the Raman spectrum. A large number of skeletal modes are obtained in this Raman spectrum for the first time.
Helix–random coil phase transitions in polypeptide systems with random defects: A statistical mechanical model
Authors: DuPré Donald B. , Salsburg Zevi W.
Published: May 2005

The statistical mechanics of the effect of a small number of randomly occurring defects on the melting of a polypeptide chain is developed by using a perturbation of Boltzmann factors technique. The method is illustrated by an example where a second‐component impurity contributes more to the energy of the hydrogen‐bonded superstructure of the polypeptide chain than does the dominant amino acid residue, resulting in the overall destabilization of the helical conformation.
Conformational studies of β‐D‐1,4′‐xylan
Authors: Sundararajan P. R. , Rao V. S. R.
Published: May 2005

The nonbonded interaction energy was computed for xylobiose and xylan as a function of the dihedral angles (ϕ,ψ). The energy maps indicate that interactions higher than the second neighbor are negligible. Of the four possibilities, the left‐handed helical conformation with (ϕ,ψ) = (63°,25°) is of the lowest energy. The hydrogen bond search and the energy maps reveal that the xylan helix is stabilized mainly by van der Waals forces. The allowed region map shows that the freedom of rotation of the monomer units in cellulose is more restricted than that of the monomer units in xylan, because of the presence of the CH2OH group in the former. The intramolecular hydrogen bond of the O5 ⃛O3′ type is stronger in cellulose.
Temperature dependence of CD spectra of DNA from various sources
Authors: Usatyi A. F. , Shlyakhtenko L. S.
Published: May 2005

The CD spectra of DNA from various sources (T2; T4; Cd; Escherichia coli; calf thymus; Streptomyces chrysomalis) were investigated. A new band Δε210 in the CD spectra of glucosylated DNA of the T even phages was found. The temperature dependence of the CD spectra of DNA was obtained over a wide range of temperatures, including those of the helix–coil transition.

The band Δε275 for all DNAs does not appreciably change in the range of the helix–coil transition. The monotonic increase of this band before melting, and its decrease after melting is observed with an increase in temperature.

The amplitude of the CD band Δε245 for all the DNAs studied and Δε210 (glucosylated DNA) parallels the change of E260 absorbance.
Investigation of the effect of amylose/iodine complexation on the conformation of amylose in aqueous solution
Authors: Senior Marilyn B. , Hamori Eugene
Published: May 2005

Using a potato amylose fraction of 8 × 105, molecular‐weight viscosity studies were carried out at 25°C on solutions containing 0.176–0.042% polymer, 8.67 mM KI, 1% ethanol, and different concentrations of iodine. By a novel extrapolation method, the intrinsic viscosities of the amylose/iodine complex were determined under various conditions of iodine binding (0–0.133 g I2/g amylose). Contrary to the view long held in this research area, it was found that the intrinsic viscosity of amylose solutions decreases significantly upon complex formation with iodine. Taking into account the results of our previous kinetic studies, the present findings are interpreted in terms of an amylose model characterized by loose, extended helical regions which are interrupted by short disordered regions. It is proposed that the intrinsic viscosity decrease observed is due to a shortening of the linear dimension of the polymer chain. This conformation change is apparently caused by the contraction of loose helical regions of the amylose macromolecule due to the entrapment of iodine (and perhaps other) atoms inside the helical cavities.