bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diel Growth Cycle of Isolated Leaf Discs Analyzed with a Novel, High-Throughput Three-Dimensional Imaging Method Is Identical to That of Intact Leaves
Authors: Biskup Bernhard , Scharr Hanno , Fischbach Andreas , Wiese-Klinkenberg Anika , Schurr Ulrich , Walter Achim 
Published: January 2009

Abstract
Dicot leaves grow with pronounced diel (24-h) cycles that are controlled by a complex network of factors. It is an open question to what extent leaf growth dynamics are controlled by long-range or by local signals. To address this question, we established a stereoscopic imaging system, GROWSCREEN 3D, which quantifies surface growth of isolated leaf discs floating on nutrient solution in wells of microtiter plates. A total of 458 leaf discs of tobacco (Nicotiana tabacum) were cut at different developmental stages, incubated, and analyzed for their relative growth rates. The camera system was automatically displaced across the array of leaf discs; visualization and camera displacement took about 12 s for each leaf disc, resulting in a time interval of 1.5 h for consecutive size analyses. Leaf discs showed a comparable diel leaf growth cycle as intact leaves but weaker peak growth activity. Hence, it can be concluded that the timing of leaf growth is regulated by local rather than by systemic control processes. This conclusion was supported by results from leaf discs of Arabidopsis (Arabidopsis thaliana) Landsberg erecta wild-type plants and starch-free1 mutants. At night, utilization of transitory starch leads to increased growth of Landsberg erecta wild-type discs compared with starch-free1 discs. Moreover, the decrease of leaf disc growth when exposed to different concentrations of glyphosate showed an immediate dose-dependent response. Our results demonstrate that a dynamic leaf disc growth analysis as we present it here is a promising approach to uncover the effects of internal and external cues on dicot leaf development.
Proteins from Multiple Metabolic Pathways Associate with Starch Biosynthetic Enzymes in High Molecular Weight Complexes: A Model for Regulation of Carbon Allocation in Maize Amyloplasts
Authors: Hennen-Bierwagen Tracie A. , Lin Qiaohui , Grimaud Florent , Planchot Véronique , Keeling Peter L. , James Martha G. , Myers Alan M. 
Published: January 2009

Abstract
Starch biosynthetic enzymes from maize (Zea mays) and wheat (Triticum aestivum) amyloplasts exist in cell extracts in high molecular weight complexes; however, the nature of those assemblies remains to be defined. This study tested the interdependence of the maize enzymes starch synthase IIa (SSIIa), SSIII, starch branching enzyme IIb (SBEIIb), and SBEIIa for assembly into multisubunit complexes. Mutations that eliminated any one of those proteins also prevented the others from assembling into a high molecular mass form of approximately 670 kD, so that SSIII, SSIIa, SBEIIa, and SBEIIb most likely all exist together in the same complex. SSIIa, SBEIIb, and SBEIIa, but not SSIII, were also interdependent for assembly into a complex of approximately 300 kD. SSIII, SSIIa, SBEIIa, and SBEIIb copurified through successive chromatography steps, and SBEIIa, SBEIIb, and SSIIa coimmunoprecipitated with SSIII in a phosphorylation-dependent manner. SBEIIa and SBEIIb also were retained on an affinity column bearing a specific conserved fragment of SSIII located outside of the SS catalytic domain. Additional proteins that copurified with SSIII in multiple biochemical methods included the two known isoforms of pyruvate orthophosphate dikinase (PPDK), large and small subunits of ADP-glucose pyrophosphorylase, and the sucrose synthase isoform SUS-SH1. PPDK and SUS-SH1 required SSIII, SSIIa, SBEIIa, and SBEIIb for assembly into the 670-kD complex. These complexes may function in global regulation of carbon partitioning between metabolic pathways in developing seeds.
discordia1 and alternative discordia1 Function Redundantly at the Cortical Division Site to Promote Preprophase Band Formation and Orient Division Planes in Maize
Authors: Wright Amanda J. , Gallagher Kimberly , Smith Laurie G. 
Published: January 2009

AbstractIn plants, cell wall placement during cytokinesis is determined by the position of the preprophase band (PPB) and the subsequent expansion of the phragmoplast, which deposits the new cell wall, to the cortical division site delineated by the PPB. New cell walls are often incorrectly oriented during asymmetric cell divisions in the leaf epidermis of maize (Zea mays) discordia1 (dcd1) mutants, and this defect is associated with aberrant PPB formation in asymmetrically dividing cells. dcd1 was cloned and encodes a putative B'' regulatory subunit of the PP2A phosphatase complex highly similar to Arabidopsis thaliana FASS/TONNEAU2, which is required for PPB formation. We also identified alternative discordia1 (add1), a second gene in maize nearly identical to dcd1. While loss of add1 function does not produce a noticeable phenotype, knock down of both genes in add1(RNAi) dcd1(RNAi) plants prevents PPB formation and causes misorientation of symmetric and asymmetric cell divisions. Immunolocalization studies with an antibody that recognizes both DCD1 and ADD1 showed that these proteins colocalize with PPBs and remain at the cortical division site through metaphase. Our results indicate that DCD1 and ADD1 function in PPB formation, that this function is more critical in asymmetrically dividing cells than in symmetrically dividing cells, and that DCD1/ADD1 may have other roles in addition to promoting PPB formation at the cortical division site.
A Novel Polyamine Acyltransferase Responsible for the Accumulation of Spermidine Conjugates in Arabidopsis Seed
Authors: Luo Jie , Fuell Christine , Parr Adrian , Hill Lionel , Bailey Paul , Elliott Katherine , Fairhurst Shirley A. , Martin Cathie , Michael Anthony J. 
Published: January 2009

Abstract
Hydroxycinnamic acid amides are a class of secondary metabolites distributed widely in plants. We have identified two sinapoyl spermidine derivatives, N-((4′-O-glycosyl)-sinapoyl),N′-sinapoylspermidine and N,N′-disinapoylspermidine, which comprise the two major polyamine conjugates that accumulate in Arabidopsis thaliana seed. Using metabolic profiling of knockout mutants to elucidate the functions of members of the BAHD acyltransferase family in Arabidopsis, we have also identified two genes encoding spermidine disinapoyl transferase (SDT) and spermidine dicoumaroyl transferase (SCT) activities. At2g23510, which is expressed mainly in seeds, encodes a spermidine sinapoyl CoA acyltransferase (SDT) that is required for the production of disinapoyl spermidine and its glucoside in Arabidopsis seed. The structurally related BAHD enzyme encoded by At2g25150 is expressed specifically in roots and has spermidine coumaroyl CoA acyltransferase (SCT) activity both in vitro and in vivo.
ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE1 (ADPG1), ADPG2, and QUARTET2 Are Polygalacturonases Required for Cell Separation during Reproductive Development inArabidopsis
Authors: Ogawa Mikihiro , Kay Pippa , Wilson Sarah , Swain Stephen M. 
Published: January 2009

AbstractCell separation is thought to involve degradation of pectin by several hydrolytic enzymes, particularly polygalacturonase (PG). Here, we characterize an activation tagging line with reduced growth and male sterility caused by increased expression of a PG encoded by QUARTET2 (QRT2). QRT2 is essential for pollen grain separation and is part of a small family of three closely related endo-PGs in the Arabidopsis thaliana proteome, including ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE1 (ADPG1) and ADPG2. Functional assays and complementation experiments confirm that ADPG1, ADPG2, and QRT2 are PGs. Genetic analysis demonstrates that ADPG1 and ADPG2 are essential for silique dehiscence. In addition, ADPG2 and QRT2 contribute to floral organ abscission, while all three genes contribute to anther dehiscence. Expression analysis is consistent with the observed mutant phenotypes. INDEHISCENT (IND) encodes a putative basic helix-loop-helix required for silique dehiscence, and we demonstrate that the closely related HECATE3 (HEC3) gene is required for normal seed abscission and show that IND and HEC3 are required for normal expression of ADPG1 in the silique dehiscence zone and seed abscission zone, respectively. We also show that jasmonic acid and ethylene act together with abscisic acid to regulate floral organ abscission, in part by promoting QRT2 expression. These results demonstrate that multiple cell separation events, including both abscission and dehiscence, require closely related PG genes.
Telling a true story or making it up: Discourse on the effectiveness of the bookshop model for public libraries
Authors: McMenemy David 
Published: January 2009

PurposeThe purpose of this paper is to examine the often cited example of the book retailer, and other commercial imperatives, as adequate models for implementation in the public library.Design/methodology/approachThe paper provides a critical reflection on some of the pertinent issues.FindingsThe paper finds that we should consider models in their entirety and not on the basis of superficial improvements to layout and design. The adoption of a commercial model within the public realm poses as many dangers as it does advantages.Practical implicationThe paper should be of interest to anyone working in public libraries, or those considering some of the issues related to the commercialisation of the public sector, especially public libraries.Originality/valueThe paper offers an original thought piece on the influence of the private sector on the public library service in the UK, and the potential this has to alter the ethos of the service.
Managing the implementation of a federated search tool in an academic library
Authors: Joint Nicholas 
Published: January 2009

PurposeThe purpose of this paper is to look at some of the broader design and management issues that occur during the implementation of a federated search tool in a modern academic library, and tries to tease out some of the background concepts that librarians should consider.Design/methodology/approachAn overview of the main advantages and disadvantages of federated search tools in comparison with existing library tools and internet search engines such as Google.FindingsA successful implementation of a federated search engine was found to depend on a radical approach which subordinates other existing library search tools to the new one‐stop search engine. This new search interface must in turn be designed for simplicity, and not to mimic existing, overly complex library information retrieval devices.Research limitations/implicationsThe emphasis is on the softer, general aspects of managing search tool implementation, rather than the hard, technical side. So, this paper may be best read in tandem with a specific description of a search tool implementation, which describes some of the technical “back office” aspects of federated search. Research developments in these technical areas may well soon lead to the elimination of some of the negative aspects which this paper presents to the non‐technical library manager simply as a “given”.Practical implicationsThis paper outlines many of the practical challenges in search tool implementation which librarians might otherwise not anticipate.Originality/valueThe approach in this investigation is to present the broader implications of search tool implementation in a way that is stripped of technical complexity, in order to show the larger management issues as clearly as possible.
Students’ attitudes towards e‐books in a Scottish Higher Education Institute
Authors: Abdullah Noorhidawati , Gibb Forbes 
Published: January 2009

PurposeThe purpose of this paper is to present the third of three inter‐related experiments investigating the use and usability of e‐books in Higher Education based on experiments conducted at the University of Strathclyde. This study has looked in greater detail at user interactions with e‐books for reference purposes by focusing on searching and browsing tasks using three search tools: back‐of the‐book index (BoBI), table of contents (ToC) and full text search (FTS).Design/methodology/approachThis study was carried out by subject‐specific users and using a between‐subjects approach. The target population was MSc and research students in the Department of Computer and Information Sciences, at the University of Strathclyde and involved a total of 45 responses.FindingsThe study found that a BoBI was more efficient compared to a ToC and FTS tool for finding information in an e‐book environment. A BoBI was found to perform the best for accurately finding relevant content in e‐books. The usability evaluation also found that a BoBI was more useful compared to a ToC for finding information in an e‐book environment.Research limitations/implicationsThe study was focused only on the usability of e‐books, and in particular on retrieval performance, user satisfaction and preferences regarding BoBI, ToC and FTS, and not on other features such as the user interface. The e‐book usability evaluation was constrained in so far as the e‐books used were: non‐fiction; in the domain of information retrieval; e‐books that already had BoBIs with hyperlinks from the BoBI to the text; e‐books that had ToCs with hyperlinks; e‐books that had FTS tools; and e‐books that were available in PDF format.Practical implicationsThe study is important in gaining a better understanding of the retrieval performance of three search tools (BoBI, ToC and FTS) for browsing for relevant, and searching for specific, information in e‐books. This will be of value for designing better e‐books and access systems.Originality/valueThe strengths and novelty of this study are the methodology that was used, the comprehensive inter‐comparison of tools, and the size of the population. The findings have supported empirically – through an assessment of the performances of BoBIs and ToCs – the need for an enhanced library catalogue system in order to improve users’ browsing and searching capabilities for relevant book content.
Mind thegap
Authors: Singh Rajesh 
Published: January 2009

PurposeWhy are some libraries more market‐oriented than others? The purpose of this paper is to answer this question by examining the pertinent issues underlying the inter‐relationship between market‐orientation and superior service performance.Design/methodology/approachAn integrated methodological approach of qualitative as well as quantitative methods was used to gain knowledge behind the market‐orientation – service performance relationship. The directors and consumers of 33 academic and special libraries participated as respondents in this study.FindingsIn total, three kinds of libraries were found: the strong; the medium; and the weak. The findings show that the higher market‐orientation is positively connected with the libraries’ superior service performance.Research limitations/implicationsThe implication of this research does suggest that thegapbetween the service provider and receiver can be closed by increasing the marketing competence of service provider.Practical implicationsThe practical implication for libraries is that it pays to be market‐oriented, the ultimate result being higher customer satisfaction.Originality/valueThe relationship between market‐orientation and service performance has yet to be explored and established in the library world. This is one of the first such studies which attempted to investigate this inter‐relationship.
Whither reference services? Views of some Ghanaian library school students
Authors: Dadzie Perpetua S. 
Published: January 2009

PurposeThe purpose of this paper is to report on the experiences of 65 five library students who visited one of three selected libraries on the campus of the University of Ghana to find out the extent to which the principles of reference services were being adhered to.Design/methodology/approachThe unobstrusive method for evaluating reference services was used. Students were specifically asked to pose two questions (specific‐search or research questions) of their choice to two different library staff at the reference desk of the selected library (The library staff were unaware of this evaluation and exhibited their real behaviors to the clients.). The choice of these types of questions was to allow the library staff to engage them in a reference interview. Their observations were to be summarized in a two page report.FindingsStudents were not only concerned with correct answers to their questions, but were influenced to return to the same library staff by certain factors such as approachability of the library staff, effective assessment of their information need, good communication skills and the attentiveness of the library staff.Practical implicationsThis exercise gave students a first‐hand experience of being information seekers and directly experiencing what ordinary users are subjected to whenever they visited libraries. This experience it is hoped would guide them when they are later employed in libraries to conform to behaviors that enhance the quality of reference interview and user satisfaction.Originality/valueThis is a modest contribution to the literature on reference services from a developing country's perspective as very few empirical studies are carried out in this area.
Thermohydrostatic analysis of capillary compensated symmetric hole‐entry hybrid journal bearing operating with non‐Newtonian lubricant
Authors: Garg H.C. , Kumar Vijay , Sharda H.B. 
Published: January 2009

PurposeEvery high speed machine, demanding high level of perfection, can operate successfully through a precise design of bearings. Such a design can be formulated after carefully studying both static and dynamic characteristics of the journal bearing. The present paper aims to describe the study of static and dynamic performance of a hole‐entry hybrid journal bearing system compensated with capillary restrictor by considering the combined influence of thermal effects and non‐Newtonian behavior of the lubricant.Design/methodology/approachThe variation of the viscosity due to the non‐Newtonian behavior of the lubricant and temperature rise is considered in the study. The numerical solution of the generalized Reynold's, equation governing the flow of the lubricant having variable viscosity along with the energy and heat conduction equations is obtained using finite element method. The non‐Newtonian lubricant has been assumed to follow the cubic shear stress law. The study includes performance of a double row symmetric hole entry hybrid journal bearing configuration containing 12 holes per row.FindingsThe results indicate that change in viscosity of lubricant affects the bearing design parameters.Originality/valueThe paper shows that accurate theoretical modeling of the bearing is an effective tool for the selection of design parameter such as bearing land width ratio (ab), restrictor design parameter (Cs2), and non‐linearity factor (K).
Research on solid film lubricant and its failure for seeker valve
Authors: Xiao Jun , Chen Jian‐min , Zhou Hui‐di , Huang Pei 
Published: January 2009

PurposeThe seeker value is a crucial part of a navigation system, able to adjust the nitrogen airflow of the system so as to manipulate guiding and tailing movement. The paper aims to determine the causes of failure of the valve system.Design/methodology/approachIn order to reduce friction and ensure the smooth operation of the valve, a new MoS2 solid film lubricant cured at room temperature, was coated on the plunger surface of the valve. SEM, EDS, and FTIR analysis was conducted.FindingsThrough analysis it was found that the lock failure of the valves was caused by the absence of MoS2 in the surface and softening and melding of the film at an extended electrifying.Originality/valueThe paper outlines the strategies to avoid lock failure – by improving the quality of the solid film lubricant and modifying the assembly process of the valve.
Tribological investigation of MPTS‐MPTES SAMs
Authors: Cheng Xianhua 
Published: January 2009

PurposeThis paper's aim is to study the tribological properties of hyrid monolayer composited by γ‐mercapto‐propyl trimethoxysilane (MPTS) and γ‐methacryloxy propyltrimethoxysilane (MPTES), and estimated the action mechanism.Design/methodology/approachMPTS‐MPTES were self‐assembled on a hydroxylated silicon substrate to form a two‐dimensional hybrid monolayer. Atomic force microscope (AFM), X‐ray photoelectron spectrometry and contact angle measurement were used to characterize the MPTS‐MPTES hybrid self‐assembled monolayer (SAM). The macrofriction and wear behaviors of the film sliding against an AISI‐52100 steel ball were examined on a unidirectional friction and wear tester, and the worn surface morphologies were observed on an AFM.FindingsThe tribological results show that the friction coefficient of silicon substrate reduces from 0.86 to 0.18 after the formation of the MPTS‐MPTES hybrid SAM on its surface, and the thin film has a long wear life (2,620 sliding pass). It is demonstrated that the MPTS‐MPTES SAM exhibited good wear resistant property with a low friction coefficient, and the superior friction reduction and wear life were attributed to the low surface energy and the characteristics of the hybrid SAM.Research limitations/implicationsThe film's tribological performance under dynamic load is not estimated.Practical implicationsA hybrid monolayer with superior tribological property was synthesized on a silicon substrate by self‐assembly process, and maybe it is the potential solution for micro‐electromechanical‐system lubrication.Originality/valueThis paper provides a study way of hybrid SAM on a silicon substrate as lubricating coating.
Tribological study of a novel borate ester containing dialkylthiophosphate group as multifunctional additive
Authors: Wang Yonggang , Li Jiusheng , Ren Tianhui 
Published: January 2009

PurposeAs multifunctional additives, ZDDP, which provides excellent oxidation resistance and superior antiwear properties, has been used widely in lubricants, however, it shows oppositional effect with friction modifiers when used together. In this paper, an attempt is made to find a novel kind of borate ester which can be used as potential substitute for ZDDP.Design/methodology/approachA novel borate ester containing dialkylthiophosphate group was prepared and characterized. Its tribological properties as an additive in synthetic ester were evaluated using a four‐ball tribometer and antioxidative ability tested by pressurized differential scanning calorimetry (PDSC). Thermal degradation tests were conducted to identify its thermal stabilities using thermogravimetric analyzer (TGA). The worn surface of the steel ball was investigated by X‐ray photoelectron spectroscopy (XPS) and the antiwear mechanism of the additive was preliminarily discussed.FindingsResults show the additive possesses outstanding loading‐carrying and friction‐reducing properties, compared with ZDDP, and can improve antiwear properties of the base oil dramatically. Moreover, it also has excellent antioxidation performance and thermal stability.Originality/valueThis paper provides a multifunctional ashless additive which possesses excellent tribological properties, and gives another selection for industrial applications in which ZDDP is needed.