The stochastic design of force-minimized compact magnets for high-field magnetic resonance imaging applications

New designs for force-minimized compact high-field clinical MRI magnets are described. The design method is a modified simulated annealing (SA) procedure which includes Maxwell forces in the error function to be minimized. This permits an automated force reduction in the magnet designs while controlling the overall dimensions of the system. As SA optimization requires many iterations to achieve a final design, it is important that each iteration in the procedure is rapid. We have therefore developed a rapid force calculation algorithm. Novel designs for short 3- and 4-T clinical MRI systems are presented in which force reduction has been invoked. The final designs provide large homogeneous regions and reduced stray fields in remarkable short magnets. A shielded 4-T design that is approximately 30% shorter than current designs is presented. This novel magnet generates a full 50-cm diameter homogeneous region.

Functional heterogeneity within rhodamine123(lo) Hoechst33342(lo/sp) primitive hemopoietic stem cells revealed by pyronin Y

Objective. The aim of this study was to determine the function of primitive hematopoietic stem cells (PHSC) at phases G(0) and G(1) of the cell cycle. Materials and Methods. A combination of supravital dyes rhodamine123 (Rh), Hoechst33342 (Ho), and pyronin (PY) was used to isolate the G(0) and G(1) subsets of PHSC. A competitive repopulation assay was used to evaluate their in vivo function. Results. We confirmed that the Rh(lo)Lin(-)Kit(+)Sca-1(+) PHSC were relatively quiescent when compared with the more mature Rh(hi)Lin(-)Kit(+)Sca-1 HSC and Rh(hi)Lin(-)Kit(+)Sca-1(-) progenitors. In addition, cells with Rh(lo)Lin(-)Kit(+)Sca-1(+), Rh(lo)Ho(lo)Lin(-)Sca-1(+), or Rh(lo)Ho(sp)Lin(-)Sca-1(+) phenotypes identified the same cell population. We further subfractionated the Rh(lo)Ho(lo/sp)Lin(-)Sca-1(+) PHSC using PY into PYlo and PYhi subsets. Limiting dilution analysis revealed that the frequency of long-term in vivo competitive repopulating units (CRU) of the (PYRhHolo/sp)-Rh-lo-Ho-lo PHSC was 1 in 10 cells, whereas there was at least a three-fold lower frequency in those isolated at the G(1) phase (PYhi) We found a dose-dependent PY-mediated cytotoxicity that at moderate concentration affected most of the murine hematopoietic compartment but spared the early HSC compartment. Conclusion. Our data confirm that the HSC compartment is hierarchically ordered on the basis of quiescence and further extend this concept to PY-mediated cytotoxicity. PY supravital dye can be used to reveal functional heterogeneity within the (RhHolosp)-Ho-lo PHSC population but is of limited use in dissecting the relatively more mature hematopoietic stem/progenitor cell population. (C) 2001 International Society for Experimental Hematology. Published by Elsevier Science Inc.

Functional annotation of a full-length mouse cDNA collection

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Cloning and functional analysis of the Sry-related HMG box gene, Sox18

The Sox gene family (Sry like HMG box gene) is characterised by a conserved DNA sequence encoding a domain of approximately 80 amino acids which is responsible for sequence specific DNA binding. We initially published the identification and partial cDNA sequence of murine Sox18, a new member of this gene family, isolated from a cardiac cDNA library. This sequence allowed us to classify Sox18 into the F sub-group of Sox proteins, along with Sox7 and Sox17. Recently, we demonstrated that mutations in the Sox18 activation domain underlie cardiovascular and hair follicle defects in the mouse mutation, ragged (Ra) (Pennisi et al., 2000. Mutations in Sox18 underlie cardiovascular and hair follicle defecs in ragged mice. Nat. Genet. 24, 434-437). Ra homozygotes lack vibrissae and coat hairs, have generalised oedema and an accumulation of chyle in the peritoneum. Here we have investigated the genomic sequences encoding Sox18. Screening of a mouse genomic phage library identified four overlapping clones, we sequenced a 3.25 kb XbaI fragment that defined the entire coding region and approximately 1.5 kb of 5' flanking sequences. This identified (i) an additional 91 amino acids upstream of the previously designated methionine start codon in the original cDNA, and (ii);ln intron encoded within the HMG box/DNA binding domain in exactly the same position as that found in the Sox5, -13 and -17 genes. The Sox18 gene encodes a protein of 468 aa. We present evidence that suggests HAF-2, the human HMG-box activating factor-2 protein, is the orthologue of murine Sox18. HAF-2 has been implicated in the regulation of the Human IgH enhancer in a B cell context. Random mutagenesis coupled with GAL4 hybrid analysis in the activation domain between amino acids 252 and 346, of Sox18, implicated the phosphorylation motif, SARS, and the region between amino acid residues 313 and 346 as critical components of Sox18 mediated transactivation. Finally, we examined the expression of Sox18 in multiple adult mouse tissues using RT-PCR. Low-moderate expression was observed in spleen, stomach, kidney, intestine, skeletal muscle and heart. Very abundant expression was detected in lung tissue. (C) 2001 Elsevier Science B.V. All rights reserved.

Laminin 10/11: an alternative adhesive ligand for epidermal keratinocytes with a functional role in promoting proliferation and migration

We have investigated the expression and function of the isoforms of laminin bearing the alpha(5) chain, i.e. laminin-10/11 in neonatal and adult human skin. By immunostaining human skin derived from a variety of anatomic sites, we found that the laminin-alpha(5) chain is expressed abundantly in the basement membrane underlying the interfollicular epidermis and the blood vessels in the dermis. Interestingly, while the expression level of the well-studied laminin-5 isoform did not change significantly with age, laminin-10/11 (a5 chain) appeared to decrease in the basement membrane underlying the epidermis, in adult skin. In contrast, the levels of laminin-10/11 in the basement membrane underlying blood vessels remained unchanged in neonatal vs. adult skin. Importantly, in vitro cell adhesion assays demonstrated that laminin-10/11 is a potent adhesive substrate for both neonatal and adult keratinocytes and that this adhesion is mediated by the alpha(3)beta(1), and alpha(6)beta(4) integrins. Adhesion assays performed with fractionated basal keratinocytes showed that stem cells, transit amplifying cells and early differentiating cells all adhere to purified laminin-10/11 via these receptors. Further, laminin-10/11 provided a proliferative signal for neonatal foreskin keratinocytes, adult breast skin keratinocytes, and even a human papillomavirus type-18 transformed tumorigenic keratinocyte cell line in vitro. Finally, laminin-10/11 was shown to stimulate keratinocyte migration in an in vitro wound healing assay. These results provide strong evidence for a functional role for laminin-10/11 in epidermal proliferation during homeostasis, wound healing and neoplasia.

The number of long-lasting functional memory CD8(+) T cells generated depends on the nature of the initial nonspecific stimulation

The mechanism of generation of memory cytotoxic T cells (CTL) following immunization remains controversial. Using tumor protection and IFN-gamma ELISPOT assays in mice to detect functional CTL, we show that the initial effector CTL burst size after immunization is not directly related to the amount of functional memory CTL formed, suggesting that memory CTL are unlikely to arise stochastically from effector CTL. Induction of MHC class II-restricted T helper cells at the time of immunization by inclusion of a T helper peptide or protein in the immunogen, is necessary to generate memory CTL, although no T helper cell induction is required to generate effector CTL to a strong MHC class I-binding peptide. Host protective T cell memory correlates with the number of CTL epitope responsive IFN-gamma-secreting memory T cells as measured in an ELISPOT assay at the time of tumor challenge. We conclude that a different antigen presenting environment is required to induce long-lasting functional memory CTL, and non-cognate stimulation of the immune system is essential to allow generation of a long-lasting host protective memory CTL response.

Theory and applications of fuzzy Volterra integral equations

Formulations of fuzzy integral equations in terms of the Aumann integral do not reflect the behavior of corresponding crisp models. Consequently, they are ill-adapted to describe physical phenomena, even when vagueness and uncertainty are present. A similar situation for fuzzy ODEs has been obviated by interpretation in terms of families of differential inclusions. The paper extends this formalism to fuzzy integral equations and shows that the resulting solution sets and attainability sets are fuzzy and far better descriptions of uncertain models involving integral equations. The investigation is restricted to Volterra type equations with mildly restrictive conditions, but the methods are capable of extensive generalization to other types and more general assumptions. The results are illustrated by integral equations relating to control models with fuzzy uncertainties.

Functional assessment tools for paediatric clients with Juvenile Chronic Arthritis: An update and review for occupational therapists

Juvenile chronic arthritis (JCA) is one cause of chronic illness and disability in childhood. Traditional clinical assessment of clients with JCA include objective measures of joint deformity, joint swelling, range of motion, duration of morning stiffness, pain, walking speed, running speed and muscle strength. In many instances, these traditional measures have little or no significance or relevance to paediatric clients and their parents whereas functional skills used in everyday living are more likely to be meaningful. Measures of physical, social, and psychological functioning ensure a comprehensive health assessment. Responsible occupational therapy assessment and management of paediatric clients diagnosed with JCA requires the use of reliable, valid and sensitive measures of function. Several instruments are now available which measure a child's or adolescent's functional abilities. In this paper, JCA and the impact of JCA on functional development are reviewed. As well, seven functional assessment tools designed for use with paediatric clients with JCA which occupational therapists can use in their clinical practice will be appraised. The various characteristics of these tools are discussed in order to assist practitioners and researchers in selecting the functional instrument which best meets their needs.

Expert review of an approach to functional capacity evaluation

Functional capacity evaluation (FCE) is a widely used tool in work rehabilitation, despite the limited examination of the soundness of its measurement properties. This paper outlines the development of a new approach to FCE, the GAPP FCE, and reports on the findings of an expert review of aspects of its content validity and technical adequacy and how it meets established test criteria. Five expert occupational therapists reviewed the materials of the GAPP FCE then completed a questionnaire related to the content validity, technical adequacy and safety, reliability, validity, practicality and utility of the GAPP FCE. The experts gave support to most aspects of these criteria. The main issue identified by the review was related to interpretation and extrapolation of the FCE results for return to work. This and other issues are discussed in relation to recent developments in FCE and plans for future development of the GAPP FCE.

Research into telehealth applications in speech-language pathology

A literature review was conducted to investigate the extent to which telehealth has been researched within the domain of speech-language pathology and the outcomes of this research. A total of 13 studies were identified. Three early studies demonstrated that telehealth was feasible, although there was no discussion of the cost-effectiveness of this process in terms of patient outcomes. The majority of the subsequent studies indicated positive or encouraging outcomes resulting from telehealth. However, there were a number of shortcomings in the research, including a lack of cost-benefit information, failure to evaluate the technology itself, an absence of studies of the educational and informational aspects of telehealth in relation to speech-language pathology, and the use of telehealth in a limited range of communication disorders. Future research into the application of telehealth to speech-language pathology services must adopt a scientific approach, and have a well defined development and evaluation framework that addresses the effectiveness of the technique, patient outcomes and satisfaction, and the cost-benefit relationship.

The nexus of value chain integration and e-business applications on public sector agriculture R&D management

We examine the potential impact of interconnectivity of value chain partnerships through electronic means (e-business practices) on the management of Public Sector Agriculture R&D in Australia. We review the changing forms of managing research and development, the forces driving these changes, and R&D processes that are theoretically consistent with the move towards value chain involvement and the increase in active constituents in Public Sector Agriculture R&D. We then explore the potential of emerging e-business models to change the patterns of inter-connectivity, speed and omnipresence of partners in the value chain. Three e-business R&D management practices are identified that provide the prerequisite flexibility necessary to take advantage of opportunistic markets. These R&D business practices are: compressing R&D to reduce time to market, fostering co-development to enter a market at the last moment and building flexible products that allow adjustment at the last possible moment. Some fundamental reallocation of existing resources will be required to meet these markets. Implications of these e-business practices for R&D management are discussed.

Optical barcoding of colloidal suspensions: applications in genomics, proteomics and drug discovery

The enormous amount of information generated through sequencing of the human genome has increased demands for more economical and flexible alternatives in genomics, proteomics and drug discovery. Many companies and institutions have recognised the potential of increasing the size and complexity of chemical libraries by producing large chemical libraries on colloidal support beads. Since colloid-based compounds in a suspension are randomly located, an encoding system such as optical barcoding is required to permit rapid elucidation of the compound structures. We describe in this article innovative methods for optical barcoding of colloids for use as support beads in both combinatorial and non-combinatorial libraries. We focus in particular on the difficult problem of barcoding extremely large libraries, which if solved, will transform the manner in which genomics, proteomics and drug discovery research is currently performed.