bluuebunny/crossref_metadata_2025 huggingface dataset:
Rootletin, a novel coiled-coil protein, is a structural component of the ciliary rootlet
Authors: Yang Jun , Liu Xiaoqing , Yue Guohua , Adamian Michael , Bulgakov Oleg , Li Tiansen
Published: November 2002

The ciliary rootlet, first recognized over a century ago, is a prominent structure originating from the basal body at the proximal end of a cilium. Despite being the largest cytoskeleton, its structural composition has remained unknown. Here, we report a novel 220-kD protein, designated rootletin, found in the rootlets of ciliated cells. Recombinant rootletin forms detergent-insoluble filaments radiating from the centrioles and resembling rootlets found in vivo. An mAb widely used as a marker for vertebrate rootlets recognizes an epitope in rootletin. Rootletin has a globular head domain and a tail domain consisting of extended coiled-coil structures. Rootletin forms parallel in register homodimers and elongated higher order polymers mediated by the tail domain alone. The head domain may be required for targeting to the basal body and binding to a kinesin light chain. In retinal photoreceptors where rootlets appear particularly robust, rootlets extend from the basal bodies to the synaptic terminals and anchor ER membranes along their length. Our data indicate that rootlets are composed of homopolymeric rootletin protofilaments bundled into variably shaped thick filaments. Thus, rootletin is the long-sought structural component of the ciliary rootlet.
Nitric Oxide Synthase-Mediated Phytoalexin Accumulation in Soybean Cotyledons in Response to the Diaporthe phaseolorumf. sp. meridionalis Elicitor
Authors: Modolo Luzia Valentina , Cunha Fernando Queiroz , Braga Márcia Regina , Salgado Ione
Published: November 2002

Phytoalexin biosynthesis is part of the defense mechanism of soybean (Glycine max) plants against attack by the fungus Diaporthe phaseolorum f. sp.meridionalis (Dpm), the causal agent of stem canker disease. The treatment of soybean cotyledons with Dpm elicitor or with sodium nitroprusside (SNP), a nitric oxide (NO) donor, resulted in a high accumulation of phytoalexins. This response did not occur when SNP was replaced by ferricyanide, a structural analog of SNP devoid of the NO moiety. Phytoalexin accumulation induced by the fungal elicitor, but not by SNP, was prevented when cotyledons were pretreated with NO synthase (NOS) inhibitors. The Dpm elicitor also induced NOS activity in soybean tissues proximal to the site of inoculation. The induced NOS activity was Ca2+- and NADPH-dependent and was sensitive to the NOS inhibitors NG-nitro-l-arginine methyl ester, aminoguanidine, and l-N6-(iminoethyl) lysine. NOS activity was not observed in SNP-elicited tissues. An antibody to brain NOS labeled a 166-kD protein in elicited and nonelicited cotyledons. Isoflavones (daidzein and genistein), pterocarpans (glyceollins), and flavones (apigenin and luteolin) were identified after exposure to the elicitor or SNP, although the accumulation of glyceollins and apigenin was limited in SNP-elicited compared with fungal-elicited cotyledons. NOS activity preceded the accumulation of these flavonoids in tissues treated with the Dpm elicitor. The accumulation of these metabolites was faster in SNP-elicited than in fungal-elicited cotyledons. We conclude that the response of soybean cotyledons to Dpm elicitor involves NO formation via a constitutive NOS-like enzyme that triggers the biosynthesis of antimicrobial flavonoids.
Synthesis and Chemistry of Highly Fluorinated Oxepane-2,7-diols
Authors: Lombardi Pamela J. , Gan Yonghong , Lemal David M.
Published: November 2002

Reduction of dimethyl perfluoroadipate with Vitride yielded the title compounds, which were also prepared by dehydration of 1H,6H-perfluorohexane-1,1,6,6-tetrol. The configurations of the oxepanediols were assigned based on the crystal structure of the bis(tert-butyldiphenylsilyl) ether of the cis stereoisomer. Treatment with ethanolic HCl ring-opened the diols to 1H,6H-1,6-diethoxyperfluorohexane-1,6-diol, and dehydration with P4O10 gave perfluorohexanedial.
Pilot study to evaluate the safety and therapeutic efficacy of topical oxifulvic acid in atopic volunteers
Authors: Snyman J.R. , Dekker J. , Malfeld S.C.K. , van Rensburg C.E.J.
Published: November 2002

The study objectives were to establish first the safety and second the therapeutic efficacy of topically applied oxifulvic acid compared to 1% hydrocortisone and placebo creams. Oxifulvic acid has established antiinflammatory properties in vitro. It also inhibits elicited ear inflammation in mice at concentrations of 4.5 and 9%. In this double‐blind cross‐over study, 23 healthy volunteers allergic to grass or house dust mite allergen were recruited and included after signing informed consent. During the initial run‐in period all volunteers were randomized to apply either 4.5 or 9% oxifulvic acid for 2 weeks on the volare aspect of one forearm (100 mm diameter) and rechallenged 21 days later to establish sensitization. Thereafter, volunteers were randomized to either placebo. 1% hydrocortisone, 4.5 or 9% oxifulvic acid creams. Creams were applied under occlusions 1 h prior to intradermal allergen challenge and every 8 h thereafter for 3 days (21‐day intervals). The surface areas of the immediate and late phase skin reactions were calculated. Liver and kidney function tests as well as full blood counts were done at screening and thereafter weekly for the first 2 weeks and then at each follow‐up visit. Topically applied oxifulvic acid had no significant effect on any of the safety parameters and also did not induce sensitization when applied on the skin. Oxifulvic acid (4.5%) caused inhibition of the elicited inflammatory reaction at 15 min and differed significantly from the 9% cream at 24 h. These changes were similar to that caused by hydrocortisone. No other significant changes were detected. Drug Dev. Res. 57:40–43, 2002. © 2002 Wiley‐Liss, Inc.
What is multi‐impulsive bulimia and can multi‐impulsive patients benefit from supervised self‐help?
Authors: Bell Lorraine , Newns Kathryn
Published: November 2002

Definitions of multi‐impulsivity and sample characteristics between studies of impulsivity vary widely leading to inconsistent results. Outcome data was examined to assess the comparative response of multi‐impulsive and non multi‐impulsive bulimic patients to a supervised self‐help CBT programme. Multi‐impulsivity was defined as the presence of two or more impulsive behaviours in the last 2 months in addition to bulimia nervosa as reported with the Multi‐Impulsivity Scale. Multi‐impulsive patients reported similar levels of bulimic behaviours but higher levels of depression at pre‐treatment. They achieved similar levels of change by the end of treatment. However, despite improvements, their levels of depressive symptoms remain high and bulimic symptoms subclinical and may be at higher risk of relapse. Copyright © 2002 John Wiley & Sons, Ltd and Eating Disorders Association.
Myogenin—A more specific target for RT‐PCR detection of rhabdomyosarcoma than MyoD1
Authors: Michelagnoli Maria P. , Burchill Susan A. , Cullinane Catherine , Selby Peter J. , Lewis Ian J.
Published: November 2002

Background

MyoD1 and myogenin are differentially expressed in early myogenesis and have been identified in rhabdomyosarcoma (RMS). This study evaluates reverse transcriptase‐polymerase chain reaction (RT‐PCR) for MyoD1 and myogenin mRNA as diagnostic markers of RMS, and the potential application of this method for the detection of small volume disease in bone marrow (BM) and peripheral blood (PB).

Procedure

Expression of MyoD1 and myogenin mRNA was examined by RT‐PCR in RMSs (9 alveolar RMS, 10 embryonal RMS, 1 pleomorphic RMS), and 21 other paediatric tumor samples (10 neuroblastoma, 10 Ewing sarcomas, and 1 Sarcoma (not otherwise specified) (S(NOS)). BM (n = 19) and PB (n = 22) samples from the same RMS study population were also examined for MyoD1 and myogenin mRNA expression.

Results

Positive expression of both markers was demonstrated in adult muscle, but not in normal PB. Myogenin mRNA was expressed in 16/18 and MyoD1 mRNA in 12/12 RMSs studied. Myogenin was not expressed in 10/10 neuroblastomas, but was present in 2/10 Ewing sarcomas. However, MyoD1 mRNA was detected in 10/10 Ewing sarcomas and 7/10 neuroblastomas. Myogenin mRNA was detected in two BM samples from children with histologically negative BM and in 1/22 PB samples. Detection of MyoD1 mRNA in BM and PB was compromised by the amplification of a similar sized, non‐specific product.

Conclusions

Myogenin mRNA is a more specific marker than MyoD1 for the diagnosis of RMS. Myogenin mRNA is potentially a useful target for the assessment of small volume disease in RMS. Med Pediatr Oncol 2003;40:1–8, © 2003 Wiley‐Liss, Inc.
Structure and dynamics of solutions of a polystyrene–polybutadiene pentablock copolymer in a styrene‐selective solvent
Authors: Bansil Rama , Nie Huifen , Koňák Čestmír , Helmstedt Martin , Lal Jyotsana
Published: November 2002

We have examined solutions of a polystyrene–polybutadiene pentablock copolymer in 1,4‐dioxane, a slightly selective solvent for polystyrene and a θ solvent for polybutadiene, with static light scattering (SLS), dynamic light scattering (DLS), and small‐angle neutron scattering (SANS). The SANS data have been analyzed with the Percus–Yevick model to represent the scattering from interacting cores, approximated as hard spheres, and with a Lorentzian function to represent the scattering from unassociated and associated polymer chains. The SANS data at 25 °C clearly reveal interacting domains, approximately 6 nm in radius, formed by the association of the insoluble polybutadiene block in the 20% sample. The 4% sample does not show such domains, whereas the 7% sample represents an intermediate situation, with both unassociated polymer and associated polymer. At higher temperatures, the domains dissolve. The DLS data for samples with concentrations of 2–22% show two diffusive modes: a fast mode corresponding to the cooperative dynamics of concentration fluctuations and a slow mode corresponding to the diffusion of clusters. The large length‐scale heterogeneities, indicated by the strong angular dependence of SLS, implies that the small microdomains of about 10–15 polybutadiene blocks are bridged by the polystyrene chains, forming large aggregates with randomly distributed crosslinks on length scales much larger than the domain size. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2807–2816, 2002
Comparing the epistemologies of scientific disciplines in two distinct domains: modern physics versus social sciences. II: Epistemology and knowledge characteristics of the ‘new’ social sciences
Authors: van Gigch John P.
Published: November 2002

Part II is devoted to the epistemology and knowledge characteristics of the ‘new’ social sciences. Part II also explains epistemological and methodological differences and similarities among scientific disciplines such as the physical sciences and the social sciences and their respective fields of application.

Part I treated the same topics in relation to the physical sciences, represented by modern physics. (SeeSystems Research and Behavioral Science, 19: 199–209 (2002)). Copyright © 2002 John Wiley & Sons, Ltd.
How process philosophy can contribute to strategic management
Authors: Styhre Alexander
Published: November 2002

Process philosophy can contribute with alternative perspectives and views to traditional strategic management theory. The Western tradition of thinking, the metaphysics of Being as presence, based upon the binary separation between transcendental ideas and appearances in the real world, has been challenged by process philosophy, from Hellenic and classical philosophy through contemporary philosophy and modern physics. Process philosophy is increasingly relevant for strategic management as everyday strategic management practice has to deal with fluid, changing and complex realities. The aim of this paper is to discuss the notion of process philosophy as being a unifying label for theoretical models that emphasize change over stability, novelty over uniformity, and becoming over being. The contribution of process philosophy to strategic management theory is not primarily ‘theoretical’ but conceptual, and aims at providing alternative perspectives on the concept of strategy. Copyright © 2002 John Wiley & Sons, Ltd.
Effective strategic and operational practices of manufacturing, service, and public sector organizations: An empirical examination
Authors: Yasin Mahmoud M. , Wafa Marwan
Published: November 2002

The objective of this empirical investigation is to gain insights into the operational strategies, practices and characteristics of 130 manufacturing, 61 services and 86 public sector organizations. Based on this survey‐based research conducted in the USA, it is concluded that operational lessons learned from the manufacturing experience may improve the operations of service and public sector organizations. In this context, benchmarking manufacturing organizations' operational know‐how may prove to be a worthy investment for service and public sector organizations. Copyright © 2002 John Wiley & Sons, Ltd.
Vezimfilho: a model for health sector response to gender violence in South Africa
Authors: Jacobs Tanya , Jewkes Rachel
Published: November 2002

Vezimfilho, a model program for the training of health care workers was developed, implemented and evaluated in close collaboration with government and non‐government partners in South Africa. It was implemented and evaluated in two districts in the Eastern Cape and Western Cape provinces, respectively. This initiative represents one of the first attempts to build capacity in the health sector to address gender‐based violence and has been a leading example of how to address within the South African context. Outputs have been the development of a model for the health sector response to gender violence, a training package Vezimfilho! and a partnership with the Department of Health to address the sustained integration of capacity building in this area.
Signal intensity changes in T2-weighted MR image of the human trapezius muscle upon cold pressor stimulation.
Authors: Inoue-Minakuchi M , Kuboki T , Maekawa K , Yanagi Y , Inoue E , Wakasa T , Kishi K , Yatani H , Clark G T
Published: November 2002

OBJECTIVE

The ability to measure hemodynamics of skeletal muscle proper is one of the major goals for muscle pain researchers. The aim of the present study was to evaluate the ability of signal intensity (SI) in T2-weighted trapezius muscle magnetic resonance imaging (MRI) to detect intramuscular hemodynamic changes during cold pressor stimulation (CPS).

MATERIALS AND METHODS

Fifteen healthy volunteers (mean age, 25.9+/-2.1 years) participated in this study. T2-weighted MRI was acquired using a 1.5 tesla MR unit with a body array coil. The slice level was set perpendicular to the muscle long axis at the mid-point of the horizontal portion of the right trapezius muscle. Cold pressor stimulation (4 degrees C) was applied to each subject's right foot and ankle for 2 min. The SI changes were recorded continuously for 7 min before, 2 min during, and 6 min after withdrawal of cold pressor stimulation. Six of these subjects also underwent a mock-CPS trial.

RESULTS

The mean SI level in T2-weighted trapezius muscle MRI significantly increased during CPS (P<0.0001, one way repeated measure ANOVA) and returned to the baseline level after cold pressor withdrawal. No statistically significant signal changes were observed across the mock-CPS trial subjects. These findings are identical to the cold pressor-induced hemodynamic changes documented in the trapezius muscle by near-infrared spectroscopy evaluation.

CONCLUSIONS

SI measurement in T2-weighted trapezius muscle MRI is sufficiently sensitive to detect intramuscular hemodynamic changes during CPS.
Alteration of the horizontal mandibular condyle size associated with temporomandibular joint internal derangement in adult females.
Authors: Kurita H , Ohtsuka A , Kobayashi H , Kurashina K
Published: November 2002

OBJECTIVES

The purpose of this retrospective study was to analyse the relationship between horizontal size of the mandibular condyle and internal derangement (ID) of the temporomandibular joint (TMJ).

METHODS

One hundred and thirty-nine joints in 88 women aged over 18 years were included in this study. The horizontal condylar size was measured in the antero-posterior and medio-lateral (ML) dimensions using axial magnetic resonance (MR) images. Radiological findings of ID were also assessed from MR imaging.

RESULTS

The condyles in the joints with permanent disk displacement were smaller than those in joints without displacement in both dimensions (Fisher's protected least significant difference, P<0.05). There were statistically significant correlations between horizontal condylar size in the ML dimension and both disk morphology and radiological stage of ID (Spearman's correlation coefficient by rank, P<0.05).

CONCLUSIONS

The results of this study suggest a possible relationship between horizontal condylar size and disk displacement. It is also suggested that the condyle becomes smaller in the ML dimension with advancement of ID.
The glandular odontogenic cyst: clinical and radiological features; review of the literature and report of nine cases.
Authors: Noffke C , Raubenheimer E J
Published: November 2002

Nine cases with glandular odontogenic cysts (GOC's) are presented bringing the total number reported in the literature to 54. Our study confirmed that most GOC's occur in the mandible, whereas maxillary lesions present only in the globulo-maxillary region. The radiological features were found to be non-distinctive and presented as well-defined radiolucencies with uni- and multilocular appearances. Most of the mandibular GOC's were unilocular, involved the symphysis region and only one extended into the ramus. All GOC's larger than 6 cm in diameter showed perforated margins radiologically. Our two multilocular GOC's demonstrated microscopic features supporting their infiltrative radiological appearance. The invasive clinical and radiological features of GOC support the notion of a possible histo-pathologic overlap between GOC and low-grade central mucoepidermoid carcinoma of the jaw.
Accumulation of endoplasmic membranes and novel membrane-bound ribosome–signal recognition particle receptor complexes inEscherichia coli
Authors: Herskovits Anat A. , Shimoni Eyal , Minsky Abraham , Bibi Eitan
Published: November 2002

In Escherichia coli, ribosomes must interact with translocons on the membrane for the proper integration of newly synthesized membrane proteins, cotranslationally. Previous in vivo studies indicated that unlike the E. coli signal recognition particle (SRP), the SRP receptor FtsY is required for membrane targeting of ribosomes. Accordingly, a putative SRP-independent, FtsY-mediated ribosomal targeting pathway has been suggested (Herskovits, A.A., E.S. Bochkareva, and E. Bibi. 2000. Mol. Microbiol. 38:927–939). However, the nature of the early contact of ribosomes with the membrane, and the involvement of FtsY in this interaction are unknown. Here we show that in cells depleted of the SRP protein, Ffh or the translocon component SecE, the ribosomal targeting pathway is blocked downstream and unprecedented, membrane-bound FtsY–ribosomal complexes are captured. Concurrently, under these conditions, novel, ribosome-loaded intracellular membrane structures are formed. We propose that in the absence of a functional SRP or translocon, ribosomes remain jammed at their primary membrane docking site, whereas FtsY-dependent ribosomal targeting to the membrane continues. The accumulation of FtsY-ribosome complexes induces the formation of intracellular membranes needed for their quantitative accommodation. Our results with E. coli, in conjunction with recent observations made with the yeast Saccharomyces cerevisiae, raise the possibility that the SRP receptor–mediated formation of intracellular membrane networks is governed by evolutionarily conserved principles.
Isolation and Characterization of a Rice Dwarf Mutant with a Defect in Brassinosteroid Biosynthesis
Authors: Mori Masaki , Nomura Takahito , Ooka Hisako , Ishizaka Masumi , Yokota Takao , Sugimoto Kazuhiko , Okabe Ken , Kajiwara Hideyuki , Satoh Kouji , Yamamoto Koji , Hirochika Hirohiko , Kikuchi Shoshi
Published: November 2002

We have isolated a new recessive dwarf mutant of rice (Oryza sativa L. cv Nipponbare). Under normal growth conditions, the mutant has very short leaf sheaths; has short, curled, and frizzled leaf blades; has few tillers; and is sterile. Longitudinal sections of the leaf sheaths revealed that the cell length along the longitudinal axis is reduced, which explains the short leaf sheaths. Transverse sections of the leaf blades revealed enlargement of the motor cells along the dorsal-ventral axis, which explains the curled and frizzled leaf blades. In addition, the number of crown roots was smaller and the growth of branch roots was weaker than those in the wild-type plant. Because exogenously supplied brassinolide considerably restored the normal phenotypes, we designated the mutantbrassinosteroid-dependent 1(brd1). Further, under darkness, brd1showed constitutive photomorphogenesis. Quantitative analyses of endogenous sterols and brassinosteroids (BRs) indicated that BR-6-oxidase, a BR biosynthesis enzyme, would be defective. In fact, a 0.2-kb deletion was detected in the genomic region ofOsBR6ox (a rice BR-6-oxidase gene) in thebrd1 mutant. These results indicate that BRs are involved in many morphological and physiological processes in rice, including the elongation and unrolling of leaves, development of tillers, skotomorphogenesis, root differentiation, and reproductive growth, and that the defect of BR-6-oxidase caused thebrd1 phenotype.
Interaction of Sulfate Assimilation with Carbon and Nitrogen Metabolism in Lemna minor
Authors: Kopriva Stanislav , Suter Marianne , von Ballmoos Peter , Hesse Holger , Krähenbühl Urs , Rennenberg Heinz , Brunold Christian
Published: November 2002

Cysteine synthesis from sulfide andO-acetyl-l-serine (OAS) is a reaction interconnecting sulfate, nitrogen, and carbon assimilation. UsingLemna minor, we analyzed the effects of omission of CO2 from the atmosphere and simultaneous application of alternative carbon sources on adenosine 5′-phosphosulfate reductase (APR) and nitrate reductase (NR), the key enzymes of sulfate and nitrate assimilation, respectively. Incubation in air without CO2 led to severe decrease in APR and NR activities and mRNA levels, but ribulose-1,5-bisphosphate carboxylase/oxygenase was not considerably affected. Simultaneous addition of sucrose (Suc) prevented the reduction in enzyme activities, but not in mRNA levels. OAS, a known regulator of sulfate assimilation, could also attenuate the effect of missing CO2 on APR, but did not affect NR. When the plants were subjected to normal air after a 24-h pretreatment in air without CO2, APR and NR activities and mRNA levels recovered within the next 24 h. The addition of Suc and glucose in air without CO2 also recovered both enzyme activities, with OAS again influenced only APR.35SO4  2− feeding showed that treatment in air without CO2 severely inhibited sulfate uptake and the flux through sulfate assimilation. After a resupply of normal air or the addition of Suc, incorporation of 35S into proteins and glutathione greatly increased. OAS treatment resulted in high labeling of cysteine; the incorporation of 35S in proteins and glutathione was much less increased compared with treatment with normal air or Suc. These results corroborate the tight interconnection of sulfate, nitrate, and carbon assimilation.
Functional Analysis of Regulatory Elements in the Gene Promoter for an Abscission-Specific Cellulase from Bean and Isolation, Expression, and Binding Affinity of Three TGA-Type Basic Leucine Zipper Transcription Factors
Authors: Tucker Mark L. , Whitelaw Catherine A. , Lyssenko Nicholas N. , Nath Pravendra
Published: November 2002

Site-directed mutagenesis was used to identify cis-acting elements that control hormonal and abscission-specific expression of the bean (Phaseolus vulgaris) abscission cellulase (BAC) promoter. Auxin inhibition of BAC promoter expression is at least in part controlled by a negatively regulated element and ethylene induction by a positively regulated element. One of a series of 15 different 10-bp mutations created in a 2.9-kb BAC promoter reduced reporter gene expression by 60%. The native sequence for this 10-bp mutation includes a TGA-type basic leucine zipper (bZIP) motif. Tandem ligation of three 18-bp BAC elements (Z-BAC), which includes the bZIP motif to a minimal −50 35S cauliflower mosaic virus promoter, enhanced expression in abscission zones (AZs) 13-fold over that of the minimal promoter alone. The native forward orientation of the Z-BAC elements was essential for high expression levels. Expression of the Z-BAC minimal construct was 3-fold greater in AZ than stems when compared with the expression levels of an internal control with an enhanced 35S cauliflower mosaic virus promoter. Polymerase chain reaction was used to identify three TGA-type bZIP transcription factors in an AZ cDNA library. One of these factors was of the class I type and two of the class II type. RNA-blot analysis was completed for these genes and electrophoretic mobility shift assays used to confirm their binding to the Z-BAC element. Electrophoretic mobility shift assay-binding affinity was greatest for the class I TGA-type bZIP factor. The results indicate a complex interaction of negative and positive regulating transcription factors that control BAC gene expression.
Rubisco Small Subunit, Chlorophylla/b-Binding Protein and Sucrose:Fructan-6-Fructosyl Transferase Gene Expression and Sugar Status in Single Barley Leaf Cells in Situ. Cell Type Specificity and Induction by Light
Authors: Lu Chungui , Koroleva Olga A. , Farrar John F. , Gallagher Joe , Pollock Chris J. , Tomos A. Deri
Published: November 2002

We describe a highly efficient two-step single-cell reverse transcriptase-polymerase chain reaction technique for analyzing gene expression at the single-cell level. Good reproducibility and a linear dose response indicated that the technique has high specificity and sensitivity for detection and quantification of rare RNA.Actin could be used as an internal standard. The expression of message for Rubisco small subunit (RbcS), chlorophyll a/b-binding protein (Cab), sucrose (Suc):fructan-6-fructosyl transferase (6-SFT), and Actin were measured in individual photosynthetic cells of the barley (Hordeum vulgare) leaf. Only Actin was found in the non-photosynthetic epidermal cells. Cab,RbcS, and 6-SFT genes were expressed at a low level in mesophyll and parenchymatous bundle sheath (BS) cells when sampled from plants held in dark for 40 h. Expression increased considerably after illumination. The amount of 6-SFT,Cab, and RbcS transcript increased more in mesophyll cells than in the parenchymatous BS cells. The difference may be caused by different chloroplast structure and posttranscriptional control in mesophyll and BS cells. When similar single-cell samples were assayed for Suc, glucose, and fructan, there was high correlation between 6-SFT gene expression and Suc and glucose concentrations. This is consistent with Suc concentration being the trigger for transcription. Together with earlier demonstrations that the mesophyll cells have a higher sugar threshold for fructan polymerization, our data may indicate separate control of transcription and enzyme activity. Values for the sugar concentrations of the individual cell types are reported.
Amphiphilic Perfluoroalkylated Derivatives of Aliphatic Triols: Hemocompatibility and Effect on Perfluorocarbon Emulsion
Authors: Církva Vladimír , Kaplánek Robert , Paleta Oldřich , Kodíček Milan
Published: November 2002

Two sets of amphiphilic perfluoroalkylated aliphatic triols were prepared in a two-step synthesis: a protected glycerol, 4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane (1) and protected 2-hydroxymethyl-2-methylpropane-1,3-diol, 5-hydroxymethyl-2,2,5-trimethyl-1,3-dioxane (11) were fluoroalkylated with racemic 2-(2,2,3,3,4,4,5,5,5-nonafluoropentyl)- (2), or 2-(2,2,3,3,4,4,5,5,6,6,7,7,7-tridecafluoroheptyl)- (3) or 2-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-heptadecafluorononyl)oxirane (4) using boron trifluoride diethyl etherate as a catalyst to afford intermediates 5-7 and 12-14, which were deprotected by re-acetalization to the target triols HOCH2CH(OH)CH2OCH2CH(OH)CH2CF2(CF2)nCF3 (n = 2, 4, 6) 8-10 and (OHCH2)2C(CH3)CH2OCH2CH(OH)CH2CF2(CF2)nCF3 (n = 2, 4, 6) 15-17. Regioselectivity of competitive fluoroalkylation of propane-1,2-diol and butane-1,3-diol appeared to be considerably dependent on the catalyst up to 93 rel.% for the preferential fluoroalkylation at the primary hydroxy group. Hemocompatibility of the triols 8-10 and 15-17, which was very high for linear-chain amphiphiles 9 and 10, showed particular dependence on the starting triol and perfluoroalkyl-chain length. All amphiphiles 8-10 and 15-17 displayed very good compatibility with perfluorodecalin-Pluronic F-68 water emulsion.
Addition of Dihalocarbenes to Vinyl Fluorides. Chemical Consequences of Fluorine Substitution. Part 3
Authors: Haufe Günter , Meyer Oliver G. J. , Mück-Lichtenfeld Christian
Published: November 2002

1-Fluoro-1-phenylethene (1a) or 1-(4-chlorophenyl)-1-fluoroethene (1b) and 2-fluorooct-1-ene (4), on reaction with chloroform and sodium hydroxide, in a two-phase system in the presence of a phase transfer catalyst, gave the corresponding dichlorocyclopropanes in good yields. In a competition experiment, 1a was shown to be slightly more reactive than styrene itself. AM1 calculations predict reasonable activation barriers for these reactions although the relative reactivity observed in the experiment is not reproduced. For the (E)- and (Z)-1-fluoro-2-phenylethenes (3), higher activation barriers were calculated, in agreement with the observation that these alkenes did not react with dichlorocarbene under these conditions. The dibromocarbene addition to 1a gave 1,1-dibromo-2-fluoro-2-phenylcyclopropane (8), which on heating with silver salts in acetic acid yielded 3-acetoxy- 2-bromo-1-fluoro-1-phenylprop-1-ene (9) by a cyclopropyl-allyl rearrangement.
[3,3] Sigmatropic Rearrangement of Some Fluorinated 1,5-Hexadienes
Authors: Dolbier William R. , Palmer Keith W. , Tian Feng , Fiedorow Piotr , Zaganiaczyk Andrzej , Koroniak Henryk
Published: November 2002

Fluorine atoms incorporated into 1,5-hexadiene molecule should influence the kinetic as well as the thermodynamic parameters of [3,3] sigmatropic rearrangement (Cope rearrangement). Within few decades is has been documented that this transformation proceeds in a concerted manner, rather than stepwise with some radical intermediates involved. Few new terminally fluorinated 1,5-hexadienes (compounds 3, 5A, 7, 9 and 5B) have been synthesized. The activation parameters of rearrangement have been determined and compared with those known for hydrocarbon analogues. While systems developing chair-like transition states (compounds 3 and 5) showed close similarity with hydrocarbon analogues (compound 1), those developing boat-like transition states (compounds 7, 9 and 5B) may proceed through radical stepwise mechanism. Computational studies of the transition states were carried out, showing that only ab initio methods (MP2 and especially DFT) can give approximate correlation with experimental data, whereas in the case of hydrocarbon analogues even simple semiempirical methods (AM1) were reliable enough to reproduce experimental results.
ADAM AND THE ANGELS: AN EXAMINATION OF MYTHIC ELEMENTS IN ISLAMIC SOURCES
Authors: Chipman Leigh
Published: November 2002

This paper examines the involvement of the angels in the creation of Adam as an example of mythopoetic activity in Islam. This involvement takes the form of the angels' reaction to Adam's creation and to Adam's superior knowledge. These themes also developed within an anti-Gnostic polemic; the figure of the First Man is important for Gnosticism no less than for Judaism or Islam, yet their visions of this figure differed greatly. The relations between Adam and the angels is an important refraction of the differences between these religions. Comparison of tales from three Islamic genres—tafsīr, ta'rīh and qisas al-anbiyā'—with rabbinical legends shows that, contrary to expectations, Islamic material provides a more mythic conception of these themes than does Jewish midrash.
Sexually transmitted diseases and sexual lifestyles of long-distance truck drivers: A clinico-epidemiologic study in south India
Authors: Manjunath J V , Thappa D M , Jaisankar T J
Published: November 2002

Our study objective was to determine the prevalence and pattern of sexually transmitted diseases (STDs) and to study sexual lifestyles of long-distance truck drivers and their assistants in south India. For this, a total of 263 truck drivers/assistants were recruited from the highway clinic from October 1999 to March 2001. All of them were sexually active and heterosexual contact was the predominant mode (99.2%). Two-thirds of them had contact with commercial sex workers (CSWs) and roughly 60% admitted alcohol consumption. One hundred and two participants (38.7%) had various STDs. The positivity rates of HIV, VDRL and HBsAg were 15.9%, 13.3% and 21.2% respectively. The higher median age, education less than primary school level, longer duration of occupation, longer duration of each trip and a previous history of genital ulcer disease were significant risk factors for the acquisition of HIV infection.
Syphilis among intravenous drug-using population: epidemiological situation in St Petersburg, Russia
Authors: Karapetyan Arman F , Sokolovsky Yevgeny V , Araviyskaya Elena R , Zvartau Edwin E , Ostrovsky Dmitri V , Hagan Holly
Published: November 2002

Introduction. An epidemic of syphilis and other sexually transmitted infections (STI) in the Russian Federation is believed to be related to the rise in injection drug use. A study was carried out in collaboration with a non-governmental organization, Foundation 'Vozvrastcheniye'. Methods: Nine hundred and ten injection drug users participating in the programme were tested for syphilis, HIV, hepatitis C virus (HCV) and hepatitis B virus (HBV); 65 participants who had laboratory markers for syphilis and 45 syphilis-negative serosurvey subjects agreed to participate in a questionnaire study. Results: Syphilis, HIV, HBV and HCV were diagnosed in 12%, 0%, 48% and 79% of drug users, respectively. Prevalence of syphilis seromarkers was nine times higher in females than in males, and strongly associated with sex work. Conclusions: The results of the study indicate that resources to treat and prevent further infections including HIV should be prioritized toward risk reduction in drug injectors and sex workers in St Petersburg.
The Case of the Disappearing Thank Yous
Authors: Sharfstein Joshua
Published: January 2024

This JAMA Forum discusses declining time and space for appreciation of what has been accomplished in clinical medicine and health policy.
Prosocial dynamics in multiagent systems
Authors: Santos Fernando P.
Published: January 2024

Meeting today's major scientific and societal challenges requires understanding dynamics of prosociality in complex adaptive systems. Artificial intelligence (AI) is intimately connected with these challenges, both as an application domain and as a source of new computational techniques: On the one hand, AI suggests new algorithmic recommendations and interaction paradigms, offering novel possibilities to engineer cooperation and alleviate conflict in multiagent (hybrid) systems; on the other hand, new learning algorithms provide improved techniques to simulate sophisticated agents and increasingly realistic environments. In various settings, prosocial actions are socially desirable yet individually costly, thereby introducing a social dilemma of cooperation. How can AI enable cooperation in such domains? How to understand long‐term dynamics in adaptive populations subject to such cooperation dilemmas? How to design cooperation incentives in multiagent learning systems? These are questions that I have been exploring and that I discussed during the New Faculty Highlights program at AAAI 2023. This paper summarizes and extends that talk.
Evaluation of Dynamic Effects of Depressive Symptoms on Physical Function in Knee Osteoarthritis
Authors: Mehta Rhea , Hochberg Marc , Shardell Michelle , Ryan Alice , Dong Yu , Beamer Brock A. , Peer Jason , Stuart Elizabeth A. , Schuler Megan , Gallo Joseph J. , Rathbun Alan M.
Published: January 2024

Objective

To assess how changes in depressive symptoms influence physical function over time among those with radiographic knee osteoarthritis (OA).

Methods

Participants from the Osteoarthritis Initiative with radiographic knee OA (n = 2,212) and complete data were identified at baseline. Depressive symptoms were assessed as a time‐varying score at baseline and the first three annual follow‐up visits using the Center for Epidemiological Studies Depression Scale (CES‐D) Scale. Physical function was measured at the first four follow‐up visits using 20‐meter gait speed meters per second. The following two marginal structural models were fit: one assessing the main effect of depressive symptoms on gait speed and another assessing time‐specific associations.

Results

Time‐adjusted results indicated that higher CES‐D scores were significantly associated with slower gait speed (−0.0048; 95% confidence interval −0.0082 to −0.0014), and time‐specific associations of CES‐D were largest during the first follow‐up interval (−0.0082; 95% confidence interval −0.0128 to −0.0035). During subsequent follow‐up time points, the influence of depressive symptoms on gait speed diminished.

Conclusion

The negative effect of depressive symptoms on physical function may decrease over time as knee OA progresses.
Progress of Gate‐Defined Semiconductor Spin Qubit: Host Materials and Device Geometries
Authors: Liu Yang , Guan Shan , Luo Jun‐Wei , Li Shu‐Shen
Published: January 2024

Quantum computing offers the potential to revolutionize information processing by exploiting the principles of quantum mechanics. Among the diverse quantum bit (qubit) technologies, silicon‐based semiconductor spin qubits have emerged as a promising contender due to their potential scalability and compatibility with existing semiconductor technologies. In this paper, the latest developments of spin qubits in gate‐defined semiconducting nanostructures made of silicon and germanium, starting from the basic properties of electron and hole states in group‐IV semiconductors, are reviewed. Specifically, various nanostructures that exploit their unique microscopic properties for qubit implementations, elaborating on the advances and challenges in experiments, are discussed. Strategies for enhancing qubit performance, such as designing new nanostructures and identifying suitable operating points, particularly those involving the valleys of electron qubits and the heavy‐hole–light‐hole mixing of hole qubits, are also highlighted. This comprehensive review thus provides valuable insights into the current state‐of‐the‐art in semiconductor quantum computing and suggests avenues for future research.
A Protein‐Adsorbent Hydrogel with Tunable Stiffness for Tissue Culture Demonstrates Matrix‐Dependent Stiffness Responses
Authors: Li Linqing , Griebel Megan E. , Uroz Marina , Bubli Saniya Yesmin , Gagnon Keith A. , Trappmann Britta , Baker Brendon M. , Eyckmans Jeroen , Chen Christopher S.
Published: January 2024

Although tissue culture plastic has been widely employed for cell culture, the rigidity of plastic is not physiologic. Softer hydrogels used to culture cells have not been widely adopted in part because coupling chemistries are required to covalently capture extracellular matrix (ECM) proteins and support cell adhesion. To create an in vitro system with tunable stiffnesses that readily adsorbs ECM proteins for cell culture, a novel hydrophobic hydrogel system is presented via chemically converting hydroxyl residues on the dextran backbone to methacrylate groups, thereby transforming non‐protein adhesive, hydrophilic dextran to highly protein adsorbent substrates. Increasing methacrylate functionality increases the hydrophobicity in the resulting hydrogels and enhances ECM protein adsorption without additional chemical reactions. These hydrophobic hydrogels permit facile and tunable modulation of substrate stiffness independent of hydrophobicity or ECM coatings. Using this approach, it is shown that substrate stiffness and ECM adsorption work together to affect cell morphology and proliferation, but the strengths of these effects vary in different cell types. Furthermore, it is revealed that stiffness‐mediated differentiation of dermal fibroblasts into myofibroblasts is modulated by the substrate ECM. The material system demonstrates remarkable simplicity and flexibility to tune ECM coatings and substrate stiffness and study their effects on cell function.
Perforin‐Mimicking Molecular Drillings Enable Macroporous Hollow Lignin Spheres for Performance‐Configurable Materials
Authors: Wang Hairong , Tan Shujun , Su Zhenhua , Li Mingfei , Hao Xiang , Peng Feng
Published: January 2024

Despite the first observations that the perforin can punch holes in target cells for live/dead cycles in the human immune system over 110 years ago, emulating this behavior in materials science remains challenging. Here, a perforin‐mimicking molecular drilling strategy is employed to engineer macroporous hollow lignin spheres as performance‐configurable catalysts, adhesives, and gels. Using a toolbox of over 20 molecular compounds, the local curvature of amphiphilic lignin is modulated to generate macroporous spheres with hole sizes ranging from 0 to 100 nm. Multiscale control is precisely achieved through noncovalent assembly directing catalysis, synthesis, and polymerization. Exceptional performance mutations correlate with the changes in hole size, including an increase in catalytic efficiency from 50% to 100%, transition from nonstick synthetics to ultrastrong adhesives (adhesion ≈18.3 MPa, exceeding that of classic epoxies), and transformation of viscous sols to tough nanogels. Thus, this study provides a robust and versatile noncovalent route for mimicking perforin‐induced structural variations in cells, representing a significant stride toward the exquisite orchestration of assemblies over multiple length scales.
High‐Toughness CO2‐Sourced Ionic Polyurea Adhesives
Authors: Ou Xu , Pan Ji , Liu Qinbo , Niu Yajuan , Zhou Yingjie , Yan Feng
Published: January 2024

Polyurea (PUa) adhesives are renowned for their exceptional adhesion to diverse substrates even in harsh environments. However, the presence of quadruple bidentate intermolecular hydrogen bonds in the polymer chains creates a trade‐off between cohesive energy and interfacial adhesive energy. To overcome this challenge, a series of CO2‐sourced ionic PUa adhesives with ultratough adhesion to various substrates are developed. The incorporated ionic segments within the adhesive serve to partially mitigate the intermolecular hydrogen bonding interactions while conferring unique electrostatic interactions, leading to both high cohesive energy and interfacial adhesive energy. The maximum adhesive strength of 10.9 MPa can be attained by ionizing the CO2‐sourced PUa using bromopropane and subsequently exchanging the anion with lithium bis(trifluoromethylsulfonyl)imide. Additionally, these ionic PUa adhesives demonstrate several desirable properties such as low‐temperature stability (−80 °C), resistance to organic solvents and water, high flame retardancy, antibacterial activity, and UV‐fluorescence, thereby expanding their potential applications. This study presents a general and effective approach for designing high‐strength adhesives suitable for a wide array of uses.
Effect of microstructure tuning by rapid heat cycle molding on the photodegradation behavior of isotactic polypropylene
Authors: Li Jiquan , Chen Yanben , Xie Jun , Jiang Shaofei , Lu Chunfu
Published: January 2024

Rapid heat cycling molding (RHCM) is an injection molding technique that improves the product quality of isotactic polypropylene (iPP) by tuning the microstructure, but its effect on the photodegradation stability remains to be investigated. In this work, the effect of RHCM tuned microstructure on the photodegradation behavior of iPP was investigated and compared with conventional injection molding (CIM). Differential scanning calorimetry (DSC), x‐ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), atomic force microscopy (AFM), and shore durometer (D scale) were used to examine the photodegradation behavior of iPP samples. The results showed that RHCM increased the crystallinity, crystal size, and β‐crystal content of iPP samples. With the increase of photodegradation time, iPP samples injected with RHCM showed higher stability in terms of microstructure and surface quality. The relative changes in CI and Ra of RHCM90 were reduced by 48% and 40% after 800 h of UV irradiation, respectively. In addition, the combined results of dynamic mechanical analysis (DMA) and UV–visible absorption spectrum showed that RHCM promoted the development of crystalline structure and reduced the mobility of the surface chain segments as well as UV absorption coefficient. These combined effects contributed positively to its photodegradation stability.
Die Nibelungenbrücke als Pilotprojekt der digital unterstützten Bauwerkserhaltung
Authors: Kang Chongjie , Voigt Chris , Eisermann Cedric , Kerkeni Naceur , Hegger Josef , Hermann Wladimir , Jackmuth Andreas , Marzahn Gero , Marx Steffen
Published: January 2024

Das Bauwesen zählt zu den Hauptkonsumenten natürlicher Ressourcen, weshalb hier Einsparungen besonders effektiv wären. Da 54 % des jährlichen Abfallaufkommens in Deutschland auf Bau‐ und Abbruchabfälle zurückzuführen sind, kann insbesondere durch den Erhalt des Bauwerksbestands ein wesentlicher Beitrag zum Umwelt‐ und Ressourcenschutz geleistet werden. Um die Lebensdauer von Bauwerken unter Wahrung deren Standsicherheit und Funktionsfähigkeit zu verlängern, bedarf es jedoch effektiver Überwachungs‐ sowie Instandhaltungskonzepte. Dieser Beitrag behandelt ein Pilotprojekt, bei dem die Nibelungenbrücke Worms als Validierungsbauwerk dient, um eine neue, digital gestützte Instandhaltungsstrategie zu entwickeln. Zunächst werden das Bauwerk sowie dessen Instandhaltungshistorie vorgestellt. Anschließend wird das Pilotprojekt in den Kontext des DFG‐Schwerpunktprogramms SPP 2388 „Hundert plus“ gesetzt. Danach werden die spezifischen Schwerpunkte des Pilotprojekts, darunter die geometrische Modellierung, das Structural Health Monitoring (SHM), der Digitale Zwilling, die Stufe‐4‐Nachrechnung und die Beurteilung der detektierten Bauwerksschäden, erläutert. Abschließend werden Schlussfolgerungen und Ausblicke gegeben.
Tailoring the Active Species Distribution of Heterogeneous Catalyst for Regulating the Chain Structure of Nascent Polyethylene
Authors: Li Wei , Wang Jingdai , Yang Yongrong
Published: January 2024

Heterogeneous catalysis is the most widely used process for ethylene polymerization in industry. Active site distribution is one of the crucial issues in the heterogeneous catalysis, which strongly influences the catalytic process and the microstructure of synthesized polyethylene. In this respect, aiming at an explicit understanding of the progress, the challenge and the possible future directions in the study of heterogeneous catalysis of ethylene polymerization, the recent strategies of designing heterogeneous catalysts are reviewed from the perspective of tailoring the active site distribution, where the regulation of chain structures, including molecular weight distribution, branch distribution and entanglement state, are highlighted. The in situ and operando characterizations are also reviewed for assisting the understanding of structural information in heterogeneous catalysts.