bluuebunny/crossref_metadata_2025 huggingface dataset:
Human hopping on very soft elastic surfaces: implications for muscle pre-stretch and elastic energy storage in locomotion
Authors: Moritz Chet T. , Farley Claire T.
Published: March 2005

During hopping in place and running, humans maintain similar center of mass dynamics by precisely adjusting leg mechanics to compensate for moderate changes in surface stiffness. We investigated the limits of this precise control by asking humans to hop in place on extremely soft elastic surfaces. We found that hoppers drastically altered leg mechanics and maintained similar center of mass dynamics despite a sevenfold change in surface stiffness(11–81 kN m-1). On the stiffest surfaces, the legs compressed in early stance and then extended in late stance in the pattern that is typical for normal bouncing gaits. On the softest surfaces, however, subjects reversed this pattern so that the legs extended up to 8 cm in early stance and then compressed by a similar distance in late stance. Consequently, the center of mass moved downward during stance by 5–7 cm less than the surface compressed and by a similar distance as on the stiffest surfaces. This unique leg action probably reduced extensor muscle pre-stretch because the joints first extended and then flexed during stance. This interpretation is supported by the observation that hoppers increased muscle activation by 50% on the softest surface despite similar joint moments and mechanical leg work as on the stiffest surface. Thus, the extreme adjustment to leg mechanics for very soft surfaces helps maintain normal center of mass dynamics but requires high muscle activation levels due to the loss of the normal extensor muscle stretch–shorten cycle.
Aging affects the retinoic acid and the triiodothyronine nuclear receptor mRNA expression in human peripheral blood mononuclear cells
Authors: Feart C , Pallet V , Boucheron C , Higueret D , Alfos S , Letenneur L , Dartigues J F , Higueret P
Published: March 2005

Background: Inadequate retinoid status has often been described as occurring with aging. Moreover, subclinical hypothyroid status has also been evoked in the elderly. Several studies performed in animals have described the crucial incidence of age-related hypo-functioning of retinoid and thyroid signalling pathways, particularly in the brain.

Objective: The aim of the present study was to clarify whether aging modifies retinoid and thyroid signalling in humans.

Methods: Using real-time RT-PCR the relative amount of mRNA of the retinoid (RARα, RARγ and RXRα) and thyroid (TRα and TRβ) nuclear receptors in peripheral blood mononuclear cells (PBMC) of young (24–57 years old,n= 22) compared with elderly (69–90 years old,n= 24) healthy subjects was quantitated. Classical plasma parameters used to characterize the retinoid and thyroid status – retinol (ROH), retinol-binding protein (RBP), free triiodothyronine (FT3) and thyroxine (FT4), thyroid-stimulating hormone (TSH) and transthyretin (TTR) – were also assessed.

Results: RARγ expression was significantly decreased in elderly versus young subjects while no modification of the retinoid-related plasma parameters ROH and RBP were emphasized by aging. Concerning thyroid criteria, the elderly exhibited an increase in TSH concentration (+39%) without significant modifications of FT3 and FT4, which indicated an age-related sub-clinical hypothyroidism. Concurrently, the amount of TR mRNA (α as well as β subtypes) was significantly decreased in the elderly.

Conclusion: These data constitute the first evidence of an age-related hypo-activation of the retinoid and thyroid nuclear pathways in PBMC. Further study of the possible association between the expression of the retinoid and thyroid nuclear receptors and age-related cognitive alterations in humans would be interesting.
Distinction in gene expression profiles demonstrated in parathyroid adenomas by high-density oligoarray technology
Authors: Forsberg Lars , Björck Erik , Hashemi Jamileh , Zedenius Jan , Höög Anders , Farnebo Lars-Ove , Reimers Mark , Larsson Catharina
Published: March 2005

Objectives: Somatic deletion of chromosome 11q13 is the most frequent genetic aberration in parathyroid adenoma. To gain further insight into the genetic etiology of parathyroid tumor development, we examined a comprehensive gene expression profile of parathyroid adenomas and normal parathyroid tissues. The results were then evaluated with respect to differences between adenomas and normal parathyroid tissue, and to the presence of loss of heterozygosity (LOH) in chromosomal region 11q13.

Design and methods: Sporadic parathyroid adenomas and normal parathyroids were hybridized against HG-U95Av2 oligonucleotide arrays (Affymetrix) containing a total of 12 625 probe sets. Quantitative real-time PCR (QRT-PCR) was performed in a larger series of parathyroid adenomas, in order to con-firm the microarray results.

Results: Cyclin D1 and c-Jun showed increased expression in adenomas vs normal parathyroids by microarray analysis and QRT-PCR, suggesting an oncogenic role of these genes in parathyroid tumor development. At unsupervised hierarchical clustering, the adenomas fell into two groups: Group I adenomas were characterized by 11q13 LOH, while Group II adenomas lacked this abnormality. In addition, a t-test analysis identified largely non-overlapping genes with differential expression in the tumors subgroups; e.g. in Group I tumors the putative oncogene ENC 1 was found highly over-expressed vs Group II adenomas.

Conclusions: The microarray analyses revealed partly distinctive and partly common expression profiles in parathyroid adenomas with and without 11q13 LOH. In addition, approximately half of the under-expressed genes were mapped to chromosome 11, in agreement with a dose effect following loss of this chromosome.
Multiscale Modeling of Deformation in Polycrystalline Thin Metal Films on Substrates
Authors: Hartmaier A. , Buehler M. J. , Gao H.
Published: March 2005

The time‐dependent irreversible deformation of a thin metal film constrained by a substrate is investigated by a mesoscopic discrete dislocation simulation scheme incorporating information from atomistic studies of dislocation nucleation mechanisms. The simulations take into account dislocation climb along the grain boundaries in the film as well as dislocation glide along slip planes inclined and parallel to the film/substrate interface. The calculated flow stress and other features are compared with relevant experimental observations. The work is focused on deformation of a polycrystalline film without a cap layer, for which diffusive processes play an important role. The dislocation‐based simulations reveal information on the prevailing deformation mechanisms under different conditions and for different film thicknesses. Despite of the limitations of the two‐dimensional dislocation model, the simulations exhibit a film thickness dependent transition between creep dominated and dislocation glide dominated deformation, which is in good agreement with experimental observations.
Unlubricated Wear Behavior of Ce‐TZP/ Al2O3 Nanocomposites Against Bearing Steel
Authors: Yang G. , Li J.‐C. , Wang G.‐C. , Yashima M. , Min S.‐L. , Chen T.‐C.
Published: March 2005

Unlubricated friction and wear tests of Ce‐TZP/Al2O3 nanocomposites against bearing steel were performed. In order to elucidate the wear mecahnism, the morphological investigation and phase structural analysis of worn surfaces were carried out by X‐ray diffractometer and scanning electron microscope. Additionally, three kinds of wear mechanisms such as plastic deformation, adhesive wear and brittle fracture have been revealed.
Vacuum Foaming of Magnesium Slurries
Authors: Renger K. , Kaufmann H.
Published: March 2005

A new production route for metallic foams the vacuum foaming technique (VFT), is presented. The principle of this technique is based on the expansion of gas pores in metal melts at low pressure. As starting materials high pressure die casting scrap and machining chips are used.
Reaction of phenyltrifluorosilane with 8‐hydroxy‐ or 8‐mercapto‐quinoline and their derivatives as a route to new heterocyclic compounds of pentacoordinate silicon
Authors: Voronkov Mikhail G. , Trofimova Olga M. , Chernov Nikolai F. , Albanov Aleksandr I. , Chipanina Nina N. , Grebneva Ekaterina A.
Published: March 2005

The protodesilylation of phenyltrifluorosilane with 8‐hydroxy‐ and 8‐mercapto‐quinoline NC9H6YH (Y: O, 1a; S, 1b) affords the novel intramolecular pentacoordinate silanes (N $\longrightarrow$ Si) 8‐(trifluorosiloxy)‐ and (N $\longrightarrow$ Si) 8‐(trifluorosilylthio)‐quinoline respectively. The (N $\longrightarrow$ Si) 8‐(Phenyldifluorosiloxy)‐ and (N $\longrightarrow$ Si) 8‐(phenyldifluorosilylthio)‐quinolines prepared by the transsilylation reaction of trimethylsilyl derivatives of heterocycles 1a and 1b by phenyltrifluorosilane possess a similar pentacoordinate structure. Copyright © 2005 John Wiley & Sons, Ltd.
First example of ‘palladium‐nanoparticle’‐catalyzed selective alcoholysis of polyhydrosiloxane: a new approach to macromolecular grafting
Authors: Chauhan Bhanu P. S. , Rathore Jitendra S. , Glloxhani Naim
Published: March 2005

‘Palladium‐polysiloxane’ nanocomposites were synthesized as stable and isolable powder by reduction of Pd(OAc)2 with polymethylhydrosiloxane, which functions as a reducing agent and as a capping agent for the generation and stabilization of ‘palladium’‐nanoclusters. Redispersion of ‘palladium‐polysiloxane’ nanocomposite in common organic solvents, in the presence of polymethylhydrosiloxane, yielded catalytically active polysiloxane‐wrapped soluble ‘palladium’‐nanoclusters. Polysiloxane‐encapsulated ‘palladium’‐nanoclusters were used as recyclable catalyst for macromolecular grafting via alcoholysis of polyhydrosiloxane. Selective alcoholysis of polyhydrosiloxane took place in fair to excellent yields under moderate reaction conditions with a variety of alcohols (primary, secondary, tertiary/sterically bulky and functional alcohols). ‘In situ’ electron microscopy studies of the reaction mixtures in conjunction with controlled poisoning experiments revealed catalytic participation of ‘palladium’‐nanoclusters during substitution reactions. Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis, characterization and applications of polysiloxane networks with immobilized pyrogallol ligands
Authors: Saadeh Salman M. , El‐Ashgar Nizam M. , El‐Nahhal Issa M. , Chehimi Mohamed M. , Maquet Jocelyne , Babonneau Florence
Published: March 2005

A porous, solid insoluble polysiloxane‐immobilized ligand system bearing pyrogallol active sites of the general formula P(CH2)3NH(CH2)3OC6H3(OH)2 (where P represents [SiO]n siloxane network) has been prepared by the reaction of 3‐aminopropylpolysiloxane with 1,3‐dibromopropane followed by the reaction with pyrogallol. 13C CP‐MAS NMR and X‐ray photoelectron spectroscopy confirmed that the pyrogallol is chemically bonded to the siloxane backbone. Thermal analysis showed that the ligand system is stable under nitrogen at relatively high temperature. The polysiloxane–pyrogallol ligand system exhibits high potential for the uptake of the metal ions (Fe3+, Co2+, Ni2+ and Cu2+). Complexation of the pyrogallol ligand system for the metal ions at the optimum conditions was found to be in the order Fe3+ > Cu2+ > Ni2+ > Co2+. Copyright © 2005 John Wiley & Sons, Ltd.
Low‐temperature preparation of crystalline barium sulfide
Authors: Tang Yongjun , Dunphy Darren R. , Kemp Richard A.
Published: March 2005

Barium sulfide (BaS) is a compound with many uses, both commercially and in the scientific research world. Normally, BaS is prepared from the high‐temperature reduction of barite (BaSO4) with carbon, a process that eliminates CO2 as a by‐product. Temperatures during the reduction step can be as high as 1200 °C. We now demonstrate that barium disilylamides can be used as precursors to the formation of crystalline BaS in their reactions with hydrogen sulfide gas. As a major advantage, the temperature of BaS production can be lowered to 25–200 °C. The by‐products formed during the reaction are ammonium sulfides, resulting from the acid–base reaction of the liberated amines with excess H2S. Fortunately, these salts decompose thermally in vacuum under mild conditions. As determined by X‐ray powder diffraction, the BaS formed in this reaction is crystalline, in the face‐centered cubic space group Fm3m. Copyright © 2005 John Wiley & Sons, Ltd.
Biorational insecticides: Mechanism and cross‐resistance
Authors: Ishaaya Isaac , Kontsedalov Svetlana , Horowitz A. Rami
Published: March 2005

Potency and cross‐resistance of various biorational insecticides, exemplified by the whitefly Bemisia tabaci, have been studied. Bemisia tabaci were exposed to the juvenile hormone mimic pyriproxyfen for the past 12 years resulting in an over 2,000‐fold resistance, but there was no appreciable cross‐resistance with the benzoylphenyl urea novaluron. Similarly, no cross‐resistance was found between pyriproxyfen and the two neonicotinoids, acetamiprid and imidacloprid. On the other hand, a slight cross‐resistance of 5–13‐fold was observed with another neonicotinoid thiamethoxam. Among the neonicotinoids, a resistant strain of B. tabaci to thiamethoxam (˜100‐fold) showed no appreciable cross‐resistance to either acetamiprid or imidacloprid, while another strain 500‐fold resistant to thiamethoxam resulted in a mild of 4–6‐fold resistance to acetamiprid and imidacloprid. In other assays, B. tabaci strain resistant to thiamethoxam (˜100‐fold) had no cross‐resistance to pyriproxyfen. Our findings indicate that no appreciable cross‐resistance was observed between the benzoylphenyl urea novaluron, the juvenile hormone mimic pyriproxyfen, and the neonicotinoids acetamiprid and imidacloprid. Hence, these compounds could be used as components in insecticide resistance management programs. Arch. Insect Biochem. Physiol. 58:192–199, 2005. © 2005 Wiley‐Liss, Inc.
Cost utility in the United States of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone for the treatment of elderly patients with diffuse large B‐cell lymphoma
Authors: Hornberger John C. , Best Jennie H.
Published: March 2005

BACKGROUND

Findings from the Groupe d'Etude des Lymphomes Adultes LNH 98‐5 study showed that rituximab added to combined cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) prolonged progression‐free survival and overall survival in adults age ≥ 60 years with diffuse large B‐cell non‐Hodgkin lymphoma (DLBCL). The current study was conducted to investigate the incremental cost utility of the addition of rituximab to CHOP (R‐CHOP) compared with CHOP alone.

METHODS

Clinical prognosis of the time to disease progression and death was estimated using published evidence from the LNH 98‐5 study (n = 399 patients) that was linked mathematically to published long‐term outcome data on patients with DLBCL. Drug‐acquisition costs were based on published data from formulary pricing sources, and the costs of cancer surveillance and end‐of‐life care were based on published literature sources. The authors assessed cost utility as the difference in costs between R‐CHOP and CHOP divided by the increase in expected overall survival adjusted for quality of life.

RESULTS

Over 5 years, it was projected that R‐CHOP would prolong overall survival by 1.04 years. The mean cumulative cost of CHOP was $3358, and the mean cost of R‐CHOP was $17,225, resulting in a cumulative net increase of $13,867. The posttreatment cancer surveillance cost for CHOP was $3950, compared with $5202 for R‐CHOP. It was estimated that R‐CHOP would have a cost‐utility ratio of $19,297 per year of life gained compared with CHOP when adjusted for quality of life. R‐CHOP remained cost effective over wide ranges of variables in sensitivity analyses.

CONCLUSIONS

Compared with CHOP alone, it was predicted that R‐CHOP would be cost effective in elderly patients with DLBCL. Cancer 2005. © 2005 American Cancer Society.
Relative contributions of desolvation, inter‐ and intramolecular interactions to binding affinity in protein kinase systems
Authors: Sims Peter A. , Wong Chung F. , Vuga Danka , McCammon J. Andrew , Sefton Bartholomew M.
Published: March 2005

In several previous studies, we performed sensitivity analysis to gauge the relative importance of different atomic partial charges in determining protein–ligand binding. In this work, we gain further insights by decomposing these results into three contributions: desolvation, intramolecular interactions, and intermolecular interactions, again based on a Poisson continuum electrostatics model. Three protein kinase–inhibitor systems have been analyzed: CDK2–deschloroflavopiridol, PKA–PKI, and LCK–PP2. Although our results point out the importance of specific intermolecular interactions to the binding affinity, they also reveal the remarkable contributions from the solvent‐mediated intramolecular interactions in some cases. Thus, it is necessary to look beyond analyzing protein–ligand interactions to understand protein–ligand recognition or to gain insights into designing ligands and proteins. In analyzing the contributions of the three components to the overall binding free energy, the PKA–PKI system with a much larger ligand was found to behave differently from the other two systems with smaller ligands. In the former case, the intermolecular interactions are very favorable, and together with the favorable solvent‐mediated intramolecular interactions, they overcome the large desolvation penalties to give a favorable electrostatics contribution to the overall binding affinity. On the other hand, the other two systems with smaller ligands only present modest intermolecular interactions and they are not or are only barely sufficient to overcome the desolvation penalty even with the aid of the favorable intramolecular contributions. As a result, the binding affinity of these two systems do not or only barely benefit from electrostatics contributions. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 668–681, 2005
The use of absorption enhancers to enhance the dispersibility of spray‐dried powders for pulmonary gene therapy
Authors: Li H.‐Y. , Seville P. C. , Williamson I. J. , Birchall J. C.
Published: March 2005

Background

Pulmonary gene therapy requires aerosolisation of the gene vectors to the target region of the lower respiratory tract. Pulmonary absorption enhancers have been shown to improve the penetration of pharmaceutically active ingredients in the airway. In this study, we investigate whether certain absorption enhancers may also enhance the aerosolisation properties of spray‐dried powders containing non‐viral gene vectors.

Methods

Spray‐drying was used to prepare potentially respirable trehalose‐based dry powders containing lipid‐polycation‐pDNA (LPD) vectors and absorption enhancers. Powder morphology and particle size were characterised using scanning electron microscopy and laser diffraction, respectively, with gel electrophoresis used to assess the structural integrity of the pDNA. The biological functionality of the powders was quantified using in vitro cell (A549) transfection. Aerosolisation from a Spinhaler® dry powder inhaler into a multistage liquid impinger (MSLI) was used to assess the in vitro dispersibility and deposition of the powders.

Results

Spray‐dried powder containing dimethyl‐β‐cyclodextrin (DMC) demonstrated substantially altered particle morphology and an optimal particle size distribution for pulmonary delivery. The inclusion of DMC did not adversely affect the structural integrity of the LPD complex and the powder displayed significantly greater transfection efficiency as compared to unmodified powder. All absorption enhancers proffered enhanced powder deposition characteristics, with the DMC‐modified powder facilitating high deposition in the lower stages of the MSLI.

Conclusions

Incorporation of absorption enhancers into non‐viral gene therapy formulations prior to spray‐drying can significantly enhance the aerosolisation properties of the resultant powder and increase biological functionality at the site of deposition in an in vitro model. Copyright © 2005 John Wiley & Sons, Ltd.
The influence of surface domains on magnetization of very soft magnetic ribbons
Authors: Sabolek S. , Babić E. , Posedel D. , Šušak M.
Published: March 2005

The influence of surface fields Hp (generated by core currents) on the parameters of M–H loops (the coercive field Hc, the maximum magnetization Mm, etc.) of amorphous and nanocrystalline Fe73.5Cu1Nb3Si15.5B7 ribbon and amorphous VITROVAC 6025Z ribbon has been investigated. In amorphous Fe73.5Cu1Nb3Si15.5B7 ribbon Hc decreases with Hp with unchanged Mm, whereas in nanocrystalline Fe73.5Cu1Nb3Si15.5B7 and VITROVAC 6025Z ribbons Hc increases with Hp and Mm decreases with Hp. This unusual increase of Hc with Hp is ascribed to the influence of Hp on the surface domain structure (SDS) and strong interaction between SDS and inner (main) domain structure (MDS) in these materials. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Annealing effect on the electrical activity of extended defects in plastically deformed p‐Si with low dislocation density
Authors: Feklisova O. V. , Pichaud B. , Yakimov E. B.
Published: March 2005

It is shown that after plastic deformation in clean conditions the most efficient recombination defects in Si are dislocation trails. The DLTS spectrum associated with the defects in the dislocation trails in p‐Si are revealed. The thermal annealing effect on the electrical properties of these extended defects has been studied. A complex annealing kinetics of defects in the dislocation trails is revealed by the EBIC and DLTS. It is shown that annealing at 800 °C essentially decreases the EBIC contrast of dislocation trails. The DLTS spectrum associated with dislocation trails is also found to disappear after such annealing. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phenology and life cycle of the annual, Chamaesyce maculata (L.) Small (Euphorbiaceae), with multiple overlapping generations in Japan
Authors: Suzuki Nobuhiko , Teranishi Shin
Published: March 2005

The phenology of germination, vegetative growth and sexual reproduction in the annual Chamaesyce maculata (L.) Small (Euphorbiaceae) were investigated in a natural population in western Japan. Seedlings emerged from mid‐June to early October, with three peaks: mid‐June, late July and late August. Plants that emerged in June commenced sexual reproduction from late July, and thereafter both vegetative growth and sexual reproduction occurred together until early November, the plants showing no switching from vegetative growth to sexual reproduction. Seedlings that emerged in June and July suffered high mortality, but most seedlings that emerged from August onward survived until the reproductive stage. The minimum size for reproduction was largest for plants that emerged early in the season, and it decreased with a delay in seedling emergence. The late emergence of seedlings that resulted in low reproductive output may be to some extent compensated for by the increased probability of survival in the seedling stage. A transplant experiment clarified that C. maculata can repeat a maximum of three overlapping generations within a year. Multiple generations per year were attained by non‐dormant seeds produced in the first and second generations and clearly resulted in an increased reproductive output per year. The life cycle with multiple overlapping generations may have been acquired in habitats where unpredictable disturbance results in temporally unsuitable conditions for germination, vegetative growth and sexual reproduction of annual plants, but where suitable conditions frequently continue over a period longer than the single generation time of annual plants.
Involving the community in cervical cancer prevention programs
Authors: Agurto I. , Arrossi S. , White S. , Coffey P. , Dzuba I. , Bingham A. , Bradley J. , Lewis R.
Published: March 2005

Underutilization of cervical cancer prevention services by women in the high‐risk age group of 30–60 years can be attributed to health service factors (such as poor availability, poor accessibility, and poor quality of care provided), to women's lack of information, and to cultural and behavioral barriers. The Alliance for Cervical Cancer Prevention (ACCP) partners have been working to identify effective ways to increase women's voluntary participation in prevention programs by testing strategies of community involvement in developing countries. The ACCP experiences include developing community partnerships to listen to and learn from the community, thereby enhancing appropriateness of services; developing culturally appropriate messages and educational materials; making access to high‐quality screening services easier; and identifying effective ways to encourage women and their partners to complete diagnosis and treatment regimens. Cervical cancer prevention programs that use these strategies are more likely to increase demand, ensure follow‐through for treatment, and ultimately reduce disease burden.
A new method for the 3‐D in vitro growth of human RT112bladder carcinoma cells using the alginate culture technique
Authors: Boxberger Hans‐Jürgen , Meyer Thomas F.
Published: March 2005

Summary— We studied the response to different in vitro culture conditions and the ability for polarization in three‐dimensional (3‐D) and two‐dimensional (2‐D) cell culture systems of the commonly used human bladder carcinoma cell line RT112. In the case of 2‐D culture the cells were grown on glass or plastic coverslips, filter membranes, or bovine lens capsules. The alginate culture technique (ACT) was used to test the effects of 3‐D cell culture on the polarization of the RT112 epithelial cells. Our studies show clear differences in the arrangement of the cells depending on the cultivation procedure. The RT112 cells cultured on glass and plastic supports were irregular and flattened in shape whereas the cells grown on filters or on lens capsules developed into 2–3 layers consisting of markedly polarized cells. However, ACT was superior to cell culture on either artificial supports or even on lens capsule. During the 3‐D cultivation the transformed epithelial cells regenerated multicellular spheroids which maintained a tissue‐like, geometrically well‐ordered and highly prismatic organization. This ACT‐induced morphogenesis is novel and distinct from that reported with conventional culture conditions. Microscopic investigations showed that RT112 cells grown in alginate were both much more tightly packed and more regularly organized compared to 2‐D cultures. In addition, the spheroidal organized cells exhibited well developed cell‐cell contacts, a distinct endoplasmatic reticulum, and a marked Golgi apparatus. In summary, ACT can be used for 3‐D in vitro growth of the transformed human epithelial cell line RT112 that offers substantial advantages over conventional cell culture methods.
Characterisation of boar sperm dynein heavy chains by UV vanadate dependent photocleavage
Authors: Gatti Jean‐Luc , Nicolle Jean‐Claude , Dacheux Jean‐Louis
Published: March 2005

Summary— Intact and Triton X‐100 demembranated boar spermatozoa possess two main heavy chains with molecular masses (Mr) of 430 and 460 kDa. These heavy chains were photocleaved within the axoneme under V1 conditions and produced two main fragments at 245 kDa and 185 kDa. Two minor fragments at 170 and 90 kDa were also obtained. In the presence of low Mg2+ (1 mM) a supplementary fragment of 200 kDa was also observed. The heavier chain was cleaved in the absence of ATP to give the 245 kDa fragment. The boar axonemal heavy chains cannot be directly extracted by high salt treatment of the demembranated sperm in presence of high level of protease inhibitors (HPI) but were extracted when the solution contained low protease inhibitor (LPI) concentrations. Electron microscopy showed that high salt treatment in presence of LPI extracted the outer arm mainly from the principal piece of the flagellum and less from the intermediate piece. Fractionation of the LPI high salt by chromatography or sucrose gradient allowed the obtention of a particle with ATPase activity, a size of 1.2 MDa and a sedimentation coefficient of about 20S. The particle was composed of two heavy chains of Mr 320 and 340 kDa. Thése heavy chains can be photocleaved under V1 conditions and in absence of Mgt+. The sucrose gradient 20S fractions contained also two chains at 110 and 87 kDa which could be either intermediate chains or proteolytic fragments of the heavy chains. A chain at 63 kDa was also associated with the 20S fraction. These results show that boar sperm dynein heavy chains are similar in molecular mass and photolytic properties compared to invertebrate or lower vertebrate sperm dyneins, and suggest that the outer arm dyneins are maintained differently within the axoneme.
EFFECTS OF CUTTING ON THE NITROGEN ECONOMY AND DRY MATTER YIELD OF LABLAB GROWN UNDER MONOCULTURE AND INTERCROPPED WITH MAIZE IN NORTHERN THAILAND
Authors: DEVKOTA N. R. , RERKASEM B.
Published: March 2005

A study was conducted to examine the effects of the time and severity of cutting lablab (Lablab purpureus), both in sole crops and intercropped with maize (Zea mays). The effects of cutting management on the dry matter (DM) yield, leaf area index (LAI), nodulation, the nitrogen (N) yield, and N fixation by lablab were measured, as were the total DM yield, grain yield, and a yield component of maize.

Two dates of lablab cutting (40 and 60 d after sowing (DAS)), and two heights of cutting (30 and 20 cm above the soil surface) were applied in factorial combinations as well as a no-cutting treatment. Maize was not cut either in monoculture or intercrops.

Intercropping lablab with maize increased the grain yields of maize from 3.2 t ha−1 to 3.8 t ha−1 if lablab was cut at 40 DAS, but delaying cutting until 60 DAS had no effect, while uncut lablab reduced the yield of maize by 10%. Intercropping lablab with maize reduced the total N yield of lablab by over 50%, from 302 to 132 kg N ha−1. Regardless of cropping system, the total N yield of lablab at 130 DAS was 24% less when lablab was cut at 60 DAS compared with 40 DAS. Cutting height did not significantly affect the total N yield of lablab. Although both cropping system and cutting time significantly affected the total N fixation by lablab at 130 DAS, there were no significant effects of cropping system, cutting time or severity of cutting on the proportion of N in lablab derived from N fixation.

Values of Land Equivalent Ratio (LER) which ranged between 1.2 and 1.6, and of Area Time Equivalent Ratio (ATER) which ranged between 1.0 and 1.4 for intercrops of maize with lablab indicated a definite advantage of intercropping. LER and ATER values were greatest when lablab was uncut, and least when lablab was cut at 60 DAS.
Pre-Conquest manuscripts from Malmesbury Abbey and John Leland's letter to Beatus Rhenanus concerning a lost copy of Tertullian's works
Authors: Carley James P. , Petitmengin Pierre
Published: March 2005

According to the treatise which he presented as a New Year's Gift to King Henry VIII in January 1546, the English antiquary John Leland (c. 1503-52) received ‘a moste gracyouse commyssion’ from the monarch in 1533 ‘to peruse and dylygentlye to searche all the lybraryes of Monasteryes and collegies of thys your noble realme’. As he travelled from monastery to monastery he compiled lists of books, some brief, some considerably more thorough. Leland had a strong interest in pre-Conquest writings and his lists testify both to lost exemplars of known texts and to otherwise unattested writings from the early period. His principles of selection were not always consistent, however, and on occasion he omitted manuscripts of historical or literary interest which he must have seen: in no sense was he setting out to be a cataloguer as such. Ultimately his enterprise was a bibliographical one and he envisaged a volume in four books, De uiris illustribus siue de scriptoribus Britannicis, of which ‘the seconde is from the tyme of Augustyne, unto the aduente of the Normanes’. The original draft of the De uiris illustribus was composed around 1535/6 – it was in part a response to Polydore Vergil's Anglica Historia published in Basel by John Bebel in 1534 – but after this burst of activity there was a gap of almost ten years before Leland's next major phase of composition.
The Law of Persecution Before the International Criminal Tribunal for the Former Yugoslavia
Authors: Roberts Ken
Published: March 2005

The various Trial Chambers of the International Criminal Tribunal for the former Yugoslavia have advanced potentially inconsistent definitions of the crime of persecution under Article 5 of the Tribunal's Statute. The Trial Chamber in the Krnojelac case, in attempting to reconcile these different approaches, has undertaken a comprehensive analysis both of the actus reus and mens rea elements constituting this offence. In the context of the Tribunal's jurisprudence, this article analyses these elements and briefly discusses other issues related to the crime of persecution.
Effect of Inclusion Body Production on Culture Turbidity and Cell Dry Weight in Growing Bacterial Cultures
Authors: Hwang Soon Ook , Feldberg Ross S.
Published: March 2005

An approach to the optimization of product yield in an inducible inclusion body‐producing system is presented. Following induction by indoleacrylic acid (IAA) of a trpLEHIVgp41 fusion protein, we found a large increase in culture turbidity and single‐cell dry weight. After an initial transition phase, new and constant values for specific growth rate, single‐cell light turbidity, and single cell dry weight were achieved, allowing for the determination of optimal conditions for product formation.
Genetic Engineering of Structural Protein Polymers
Authors: Cappello Joseph , Crissman John , Dorman Mary , Mikolajczak Marcia , Textor Garret , Marquet Magda , Ferrari Franco
Published: March 2005

Genetic and protein engineering are components of a new polymer chemistry that provide the tools for producing macromolecular polyamide copolymers of diversity and precision far beyond the current capabilities of synthetic polymer chemistry. The genetic machinery allows molecular control of chemical and physical chain properties. Nature utilizes this control to formulate protein polymers into materials with extraordinary mechanical properties, such as the strength and toughness of silk and the elasticity and resilience of mammalian elastin. The properties of these materials have been attributed to the presence of short repeating oligopeptide sequences contained in the proteins, fibroin, and elastin. We have produced homoblock protein polymers consisting exclusively of silk‐like crystalline blocks and elastin‐like flexible blocks. We have demonstrated that each homoblock polymer as produced by microbial fermentation exhibits measurable properties of crystallinity and elasticity. Additionally, we have produced alternating block copolymers of various amounts of silk‐like and elastin‐like blocks, ranging from a ratio of 1:4 to 2:1, respectively. The crystallinity of each copolymer varies with the amount of crystalline block interruptions. The production of fiber materials with custom‐engineered mechanical properties is a potential outcome of this technology.
Long‐Term in Vitro Function of Adult Hepatocytes in a Collagen Sandwich Configuration
Authors: Dunn James C. Y. , Tompkins Ronald G. , Yarmush Martin L.
Published: March 2005

In an effort to reconstruct the cellular polarity normally found in the liver, adult rat hepatocytes were sandwiched between two layers of hydrated rat tail tendon collagen matrix. Functionally, sandwiched hepatocytes maintained the secretion of albumin, transferrin, fibrinogen, bile acids, and urea for at least 6 weeks, whereas cells cultured on a single layer of collagen gel ceased such secretion in 1–2 weeks. After 1 week of culture on a single layer of collagen gel, hepatocytes could still recover these lost functions when a second layer of collagen gel was applied. The exact nature of the substrate for constructing the sandwich system appeared to be unimportant as long as it allowed cellular attachment. Hepatocytes cultured in the sandwich system appeared to maintain a distribution of actin filaments similar to the in vivo state, whereas cells cultured on a single layer of collagen gel showed abnormal formation of stress fibers. These studies suggest that simple manipulations of the configuration of extracellular elements can dramatically alter the behavior of cultured hepatocytes.
Mathematical Model for the Effects of Epidermal Growth Factor Receptor Trafficking Dynamics on Fibroblast Proliferation Responses
Authors: Starbuck Cindy , Lauffenburger Douglas A.
Published: March 2005

We apply a mathematical model for receptor‐mediated cell uptake and processing of epidermal growth factor (EGF) to analyze and predict proliferation responses to fibroblastic cells transfected with various forms of the EGF receptor (EGFR) to EGF. The underlying conceptual hypothesis is that the mitogenic signal generated by EGF/EGFR binding on the cell surface, via stimulation of receptor tyrosine kinase activity, is attenuated when the receptors are downregulated and growth factor is depleted by endocytic internalization and subsequent intracellular degradation. Hence, the cell proliferation rate ought to depend on receptor/ligand binding and trafficking parameters as well as on intrinsic receptor signal transduction properties. The goal of our modeling efforts is to formulate this hypothesis in quantitative terms. The mathematical model consists of kinetic equations for binding, internalization, degradation, and recycling of EGF and EGFR, along with an expression relating DNA synthesis rate to EGF/EGFR complex levels. Parameter values have been previously determined from independent binding and trafficking kinetic experiments on B82 fibroblasts transfected with wild‐type and mutant EGFR. We show that this model can successfully interpret literature data for EGF‐dependent growth of NR6 fibroblasts transfected with wild‐type EGFR. Moreover, it successfully predicts the literature observation that NR6 cells transfected with a Δ973 truncation mutant EGFR, which is kinase‐active but internalization‐deficient, require an order of magnitude lower EGF concentration than cells with wild‐type EGFR for half‐maximal proliferation rate. This result demonstrates that it may be feasible to genetically engineer mammalian cell lines with reduced growth factor requirements by a rational, nonempirical approach. We explore by further model computations the possibility of exploiting other varieties of EGFR mutants to alter growth properties of fibroblastic cells, based on relationships between changes in the primary structure of the EGF receptor and the rates of specific receptor/ligand binding and trafficking processes. Our studies show that the ability to predict cell proliferation as a function of serum growth factors such as EGF could lead to the designed development of cells with optimized growth responses. This approach may also aid in elucidation of mechanisms underlying loss of normal cell proliferation control in malignant transformation, by demonstrating that receptor trafficking dynamics may in some cases play as important a role as intrinsic signal transduction in determining the overall resulting mitogenic response.
Immunoadsorption: Strategies for Antigen Elution and Production of Reusable Adsorbents
Authors: Yarmush Martin L. , Antonsen K. Pickard , Sundaram Srikanth , Yarmush David M.
Published: March 2005

Immunoadsorption is a powerful and generalizable method for protein purification that exploits the fine specificity of antigen‐antibody interactions. In spite of its potential utility, the more widespread process scale use of immunoadsorption has been limited by the high cost of the antibody and the lack of gentle elution schemes that completely preserve the activity of both the immunoadsorbent and the eluted product. In this report, we review common chemical elution strategies such as pH, ionic strength, chaotropic salts, denaturants, and organic solvents as well as physical techniques such as pressure, electrokinetics, and temperature. In general, selection of elution strategies has largely been an empirical art, balancing stability of the immunoadsorbent and the eluted product and efficiency. The limitations of the available choices demonstrate that more attention must be placed on the antibody. Techniques which assist in the identification or creation of new antibodies with improved binding properties and resistance to degradation, e.g., screening and/or rational protein engineering, are also discussed.
Mixing of Highly Viscous Simulated Xanthan Fermentation Broths with the Lightnin A‐315 Impeller
Authors: Galindot Enrique , Nienow Alvin W.
Published: March 2005

The power characteristics of the Lightnin A‐315 impeller have been evaluated in solutions of Xanthan and Carbopol of similar rheological properties, the latter being transparent to allow flow visualization. With the impeller pumping downward (forward mode), at Re<20, Po α Re−1; for 20≤Re≤300, Po α Re−½; and at Re>600, Po was almost constant ≃1. In addition, for 20≤Re≤250, higher values of Po were found at equal Re, at higher levels of elasticity in the fluids. In the reverse mode, the same trend was found although Po was lower at the same Re. Upon aeration, no significant influence of the aeration rate (0.25−1.0vvm) upon the gassed power was observed. In the forward mode, a decrease in the Pog/Po ratio was observed, reaching levels of about 0.5–0.6 at the highest stirring speed (∼7 s−1, Re=200–800). During operation in the reverse mode, a minimum (or a plateau) Pog/Po value was observed and better gas dispersion was achieved. With the highest Xanthan concentration (35 kg m−3), high torque fluctuations were observed, though these were negligible in the inelastic Carbopol solutions of similar apparent viscosity. Video recordings made with transparent Carbopol solutions revealed very poor gas dispersion. Well‐defined “caverns” were also observed in the Carbopol solution. The reverse mode gave cavern volumes up to 60% larger than the forward mode, if the modes are compared at the same power drawn. The previously derived equations for cavern sizes which have been shown to predict well for a range of impellers were not found to be entirely satisfactory with this one in either pumping mode. Although the A‐315 impeller may not be a suitable impeller for mixing highly concentrated Xanthan broths because of the drastic power drop and large torque instabilities, the reverse mode is an interesting possibility for moderately concentrated Xanthan broths giving better gas dispersion, less torque fluctuations, lower power drop, and larger cavern volumes than the forward, downward pumping mode.
A Model for β‐Galactosidase Production with a Recombinant Yeast Saccharomyces cerevisiae in Fed‐Batch Culture
Authors: Hardjito Linawati , Greenfield Paul F. , Lee Peter L.
Published: March 2005

An unstructured model is developed to describe the growth and product formation behavior of a recombinant yeast Saccharomyces cerevisiae using β‐galactosidase as a model protein. The model shows good agreement with the experimental data over a range of conditions. It also accurately predicts the effect of growth rate on yield coefficient and gene expression. The simplicity and accuracy of the model make it suitable for designing and implementing control and optimization strategies for the production of recombinant proteins at large scale.
An Anionic Galactomannan Polysaccharide Gum from a Newly‐Isolated Lactose‐Utilizing Bacterium. I. Strain Description and Gum Characterization
Authors: Flatt James H. , Hardin Robert S. , Gonzalez Juan M. , Dogger Dina E. , Lightfoot Edwin N. , Cameron Douglas C.
Published: March 2005

As part of an effort to obtain microorganisms able to produce polysaccharide gums from whey and whey permeate, soil samples from farm fields regularly treated with whey were screened for bacteria able to produce gums from lactose. The most promising organism isolated (ATCC 55046) is a facultative anaerobe, tentatively identified as a new Erwinia species on the basis of biochemical and morphological tests. The organism produces a polysaccharide gum from lactose and other sugars (herein named lactan gum) composed of mannose, galactose, and galacturonic acid with an approximate molar ratio of 5:3:2 and containing no organic acid modifying groups. The weight average molecular weight of the gum is approximately 7 × 106. Aqueous solutions of lactan gum exhibit shear‐thinning and elastic flow behavior with an estimated power law model flow index of 0.26 at 1 % (w/w) gum. The viscosity of aqueous 1 % (w/w) lactan gum solutions is stable over a pH range of 2–11, being particularly stable in alkaline environments. Aqueous 1% (w/w) gum solutions at pH 5–11 show excellent thermostability, retaining at least 80% of the original viscosity after being heated to 121 °C for 15 min. These flow properties indicate potential industrial applications in food and nonfood products requiring a moderate degree of thickening, wet‐end additives and coating agents for paper products, ceramics, detergents, and binders for building materials.
Monitoring Intracellular Protein Profiles with Two‐Dimensional Gel Electrophoresis
Authors: Dykstra Kevin H. , Wang Henry Y.
Published: March 2005

Two‐dimensional polyacrylamide gel electrophoresis (2D PAGE) is a method of separating complex protein mixtures, such as whole cell extracts, on the basis of protein isoelectric point and molecular weight. In bioprocess engineering, conventional 2D PAGE has tremendous potential to yield detailed information on the intracellular effect of various process conditions. It has been used in our work to examine global intracellular changes occurring in a typical cycloheximide fermentation and to look at the feedback regulatory behavior of cycloheximide biosynthesis. Application of the technique for bioprocess monitoring will require that the time necessary for preparation of a 2D electropherogram be substantially shortened. This may be accomplished by performing the separation on a miniature scale or eventually by use of capillary electrophoresis for one or more of the separations. Advantages and disadvantages of these two approaches are discussed.
Affinity Precipitation of Proteins by Surfactant‐Solubilized, Ligand‐Modified Phospholipids
Authors: Powers Daniel D. , Willard Betsy L. , Carbonell Ruben G. , Kilpatrick Peter K.
Published: March 2005

The use of ligand‐modified phospholipids solubilized in aqueous solution by nonionic surfactant for affinity precipitation of proteins is described. Avidin was precipitated by contact with solutions in which dimyristoylphosphatidylethanolamine (DMPE) functionalized with biotin (DMPE‐B) was solubilized in octaethylene glycol mono‐n‐dodecyl ether (C12E8) solutions. The nonionic surfactant solubilizes the phospholipid in micelles above its critical micelle concentration (CMC) and in small submicellar aggregates below this concentration. At C12E8 concentrations significantly exceeding its CMC, determined to be about 100 μM, precipitation of avidin by solubilized DMPE‐B is not observed. In this regime, binding of protein by DMPE‐B was monitored by a hyperchroic shift in the protein's UV–visible spectrum at 231.5 nm. The data were analyzed using a model that considers the four binding sites on the protein to be independent and identical in binding strength for DMPE‐B. Below the CMC of C12E8, precipitation is observed and is monitored by increasing turbidity of the solution. The kinetics of precipitation and the aggregate size measured by quasielastic light scattering were analyzed using Smoluchowski kinetics and the Mie scattering theory. These results help establish more completely the factors that influence the precipitation of proteins by ligand‐modified phospholipids, and they are helpful in specifying conditions for the precipitation of other proteins.