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Molecular profiling to characterize the effects of environmental exposures is important from the human health and performance as well as the occupational medicine perspective in space exploration. We have developed a novel exosome-based platform that allows profiling of biological processes in the body from a variety of body fluids. The technology is suitable for diagnostic applications as well as studying the pathophysiology of the Space Associated Neuro-Ocular Syndrome in astronauts and monitoring patients with chronically impaired cerebrospinal fluid drainage or elevated intracranial pressure. In this proof-of-concept, we demonstrate that: (a) exosomes from different biofluids contain a specific population of RNA transcripts; (b) urine collection hardware aboard the ISS is compatible with exosome gene expression technology; (c) cDNA libraries from exosomal RNA can be stored in dry form and at room temperature, representing an interesting option for the creation of longitudinal molecular catalogs that can be stored as a repository for retrospective analysis.

The acquisition of cell motility is an early step in melanoma metastasis. Here we use intravital imaging of signalling reporter cell-lines combined with genome-wide transcriptional analysis to define signalling pathways and genes associated with melanoma metastasis. Intravital imaging revealed heterogeneous cell behaviour in vivo: less than 10% of cells were motile and both singly moving cells and streams of cells were observed. Motile melanoma cells had increased Notch- and SRF-dependent transcription. Subsequent genome-wide analysis identified an overlapping set of genes associated with high Notch and SRF activity. We identified EZH2, a histone methyltransferase in the Polycomb Repressor Complex 2, as a regulator of these genes. Heterogeneity of EZH2 levels is observed in melanoma models and co-ordinated up-regulation of genes positively regulated by EZH2 is associated with melanoma metastasis. EZH2 was also identified as regulating the amelanotic phenotype of motile cells in vivo by suppressing expression of the P-glycoprotein Oca2. Analysis of patient samples confirmed an inverse relationship between EZH2 levels and pigment. EZH2 targeting with siRNA and chemical inhibition reduced invasion in mouse and human melanoma cell lines. The EZH2 regulated SRF target genes KIF2C and KIF22 are required for melanoma cell invasion and important for lung colonisation. We propose that heterogeneity in EZH2 levels leads to heterogeneous expression of a cohort of genes associated with motile behaviour including KIF2C and KIF22. EZH2 dependent increased expression of these genes promotes melanoma cell motility and early steps in metastasis.

We catalogue configurations that locally minimize energy for a planar elastic rod (extensible-shearable or inextensible-unshearable) subject to arbitrary Dirichlet boundary conditions in position and orientation. Via a combination of analysis and computation, we determine several bifurcation surfaces in the 3-parameter space of boundary conditions and explore how they depend on the rod material parameters, including in the inextensible limit. For each possible boundary condition, we find all stable equilibria with sufficiently low energy that they might be competitive within a Boltzmann distribution if the rod were used to model DNA with tens or hundreds of base pairs, the length-scale relevant for DNA looping. Depending on the boundary conditions, there are as many as three such equilibria.

Academic research has produced many model-based specification and analysis techniques, however, most organisations continue to document requirements as textual statements. To help bridge this gap between academic research and requirements practice, this paper reports an extension to the RESCUE process in which patterns for generating requirements statements from i* system models were manually applied to i* models developed for a complex air traffic control system. The paper reports the results of this application and describes them with examples, the benefits of the approach to the project, and ongoing research to implement these patterns in the REDEPEND modelling tool to make requirements engineers more productive. We review similar work on requirements modelling and expression, and compare our work to it to demonstrate the proposed advance in the state of the art. Finally the paper discusses future uses of requirements generation from model patterns in RESCUE.

A stability index is computed for the n-covered circular equilibria of inextensible-unshearable elastic rods with constant planar intrinsic curvature u and constant values for the twisting stiffness and two bending stiffnesses. A simple expression is derived for the index as a function of u, ρ (the ratio of bending stiffness out of the plane of curvature to bending stiffness in the plane of curvature), and γ (the ratio of twisting stiffness to bending stiffness in the plane of curvature). In particular, for intrinsically straight rods (u = 0) we prove that the 1-covered circle is stable if and only if ρ ≥ 1, and the n-covered circle (n>1) is stable if and only if γ>1, ρ>1, and $$\frac{{n - 1}}{n} \leqslant \sqrt {\frac{{\gamma - 1}}{\gamma } \cdot \frac{{\rho - 1}}{\rho }} .$$

This study describes the effects of the glucolipid synthase inhibitor P4, (DL-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol), on various functional and phenotypic parameters of 5T33 murine myeloma cells. Cell recovery was reduced by >85% following incubation of the cells for 3 days in the presence of 4 μM P4 (the IC50 concentration). Both cytostatic and cytotoxic inhibition was observed with tumour cell metabolic activity and clonogenic potential reduced to 42% and 14% of controls, respectively, and viability reduced to 52%. A dose-dependent increase in cells undergoing apoptosis (from 7% to 26%) was also found. P4 induced a decrease in the number of cells expressing H-2 Class I and CD44, and a large increase in cells expressing H-2 Class II and the IgG2b paraprotein. It did not affect surface expression of CD45 or CD54 (ICAM-1). Based on these alterations in tumour cell growth, adhesion molecule expression and potential immunogenicity, it is anticipated that P4 will provide a novel therapeutic approach for the treatment of multiple myeloma. In addition, given that essentially all tumours rely heavily on overexpressed or abnormal glucosphingolipids for growth, development and metastasis, glucolipid synthase inhibitors may prove to be universally effective anti-cancer agents. © 1999 Cancer Research Campaign

The effects of tributyltin (TBT) to the life cycle of the estuarine fish Cyprinodon variegatus were examined in a 180-day flow-through exposure. The study was initiated with embryos less than 24 h postfertilization and monitored through hatch, maturation, growth, and reproduction under continuous exposure to mean measured TBT concentrations of 5.4, 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Progeny isolated at the onset of reproduction by the parental generation (F0) were monitored for survival as embryos, survival as fry/juveniles, and growth 30 days postisolation. TBT, at a concentration of 5.4 microg/L, significantly reduced embryo survival of the F0 generation sheepshead minnows. By day 145 of the exposure, significant effects to the survival of this generation increased and included all test concentrations/=0.66 microg/L. Survival of 0.66 microg/L was reduced 59% relative to control survival by termination of the F0 generation. Growth of F0 generation organisms as measured by standard length was significantly reduced only on day 90 at 3.2 microg/L, however no significant reductions of wet or dry weight related to treatment concentration were detected. Due to complete mortality of organisms exposed to 5.4 microg/L by study day 7, effects to fecundity and progeny were monitored at measured concentrations of 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Fecundity, as measured by the production of viable eggs produced per female per day, was unaffected by any of the test treatments. All F1 generation embryos isolated from treatment chambers into 3.2 microg/L died. Survival, standard length, wet and dry weight of the F1 generation at the remaining treatment concentrations were unaffected. The results of this study indicate that exposure to TBT reduced survival of the F0 generation sheepshead minnow and establishes the lowest observed effect concentration (LOEC) as 0.66 microg TBT/L, and the no observed effect concentration (NOEC) as 0.41 microg TBT/L for this species.http://link.springer-ny. com/link/service/journals/00244/bibs/37n2p258.html

Spot form of net blotch (SFNB) (Pyrenophora teres f maculata) is an economically damaging foliar disease of barley in many of the world’s cereal growing areas. The development of SFNB-resistant cultivars may be accelerated through the use of molecular markers. A screen for SFNB resistance in 96 lines identified four new sources of resistance, including a feed variety, ‘Galleon’, for which a fully mapped doubled haploid population was available. Segregation data indicated SFNB resistance was conferred by a single gene in the ‘Galleon’בHaruna Nijo’ cross, positioned on the long arm of chromosome 7H. This gene is designated Rpt4 and is flanked by the RFLP loci Xpsr117(D) and Xcdo673 at distances of 6.9 cM and 25.9 cM, respectively. The marker Xpsr117(D) was validated using another population segregating for Rpt4, correctly predicting SFNB resistance with more than 90% accuracy.

Boron toxicity has been recognised as an important problem limiting production in the low-rainfall regions of southern Australia, West Asia and North Africa. Genetic variation for boron toxicity tolerance in barley has been characterised but the mode of inheritance and the location of genes controlling tolerance were not previously known. A population of 150 doubled-haploid lines from a cross between a boron toxicity tolerant Algerian landrace, Sahara 3771, and the intolerant Australian cultivar Clipper was screened in four tolerance assays. An RFLP linkage map of the Clipper×Sahara population was used to identify chromosomal regions associated with boron tolerance in barley. Interval regression-mapping allowed the detection of four chromosomal regions involved in the boron tolerance traits measured. A region on chromosome 2H was associated with leaf-symptom expression, a region on chromosome 3H was associated with a reduction of the affect of boron toxicity on root growth suppression, a region on chromosome 6H was associated with reduced boron uptake, and a region on chromosome 4H was also associated with the control of boron uptake as well as being associated with root-length response, dry matter production and symptom expression. The benefits and potential of marker-assisted selection for boron toxicity tolerance are discussed.

The cereal cyst nematode (CCN), Heterodera avenae Woll., is an economically damaging pest of barley in many of the world’s cereal-growing areas. The development of CCN-resistant cultivars may be accelerated through the use of molecular markers. A number of resistance genes against the pest are well known; one of them, the single dominant Ha 2 resistance gene, has been shown to be effective against the Australian pathotype and maps to chromosome 2 of barley. Segregation analysis identified two restriction fragment length polymorphism (RFLP) markers flanking the resistance gene in two doubled-haploid populations of barley. AWBMA 21 and MWG 694 mapped 4.1 and 6.1 cM respectively from the Ha 2 locus in the Chebec×Harrington cross and 4.0 and 9.2 cM respectively in the Clipper×Sahara cross. Analysis of a further seven sources of CCN resistance in the form of near-isogenic lines (NILs) indicates that all available sources of resistance to the Australian pathotype of CCN in barley represent the Ha 2 locus.

There is abundant experimental evidence suggesting the existence of attractive interactions among identically charged polyelectrolytes in ordinary salt solutions. The presence of multivalent counterions is not required. We review the relevant literature in detail and conclude that it merits more attention than it has received. We discuss also some recent observations of a low ionic strength attraction of negatively charged DNA to the region of a negatively charged glass nanoslit where the floor of the nanoslit meets the walls, again in the absence of multivalent ions. On the theoretical side, it has become clear that purely electrostatic interactions require the presence of multivalent counterions if they are to generate like-charge attraction. Any theory of like-charge attraction in the absence of multivalent counterions must therefore contain a non-electrostatic component. We point out that counterion condensation theory, which has predicted like-charge polyelectrolyte attraction in an intermediate range of distances in ordinary 1:1 salt conditions, contains both electrostatic and non-electrostatic elements. The non-electrostatic component of the theory is the modeling constraint that the counterions fall into two explicit populations, condensed and uncondensed. As reviewed in the paper, this physically motivated constraint is supported by strong experimental evidence. We proceed to offer an explanation of the nanoslit observations by showing in an idealized model that the line of intersection of two intersecting planes is a virtual polyelectrolyte. Since we have previously developed a counterion condensation theory of attraction of two like-charged polyelectrolytes, our suggestion is that the DNA is attracted to the virtual polyelectrolytes that may be located in the nanoslit where floor meets walls. We present the detailed calculations needed to document this suggestion: an extension of previous theory to the case of polyelectrolytes with like but not identical charges; the demonstration of counterion condensation on a plane with bare charge density greater than an explicitly exhibited critical value; a calculation of the free energy of the plane; a calculation of the interaction of a line charge polyelectrolyte with a like-charged plane; and the detailed demonstration that the line of intersection of two planes is a virtual polyelectrolyte.

Malignant mesothelioma arises in serosal tissues, is locally invasive, and is usually resistant to chemotherapeutic agents used clinically. To determine whether resistance to cytotoxic drugs was an inherent characteristic of mesothelioma cells, we performed in vitro chemosensitivity testing on five fully characterised human malignant mesothelioma cell lines and, for comparison, on three lines representative of clinically drug-resistant solid-tissue carcinomas using the MTT (tetrazolium bromide) assay system. Mesothelioma cell lines were intrinsically resistant to eight common antineoplastic drugs, with concentrations that produced a 50% reduction in optical density (IC50 values) for all drugs being equivalent, if not higher, for mesothelioma cell lines as compared with lung and colon carcinoma cell lines. We then investigated the direct anti-mesothelioma activity of recombinant human cytokines with their antineoplastic properties. All five mesothelioma cell lines were resistant to tumour necrosis factor, but they displayed varying degrees of sensitivity to interferons (IFNs). IFN gamma directly inhibited the growth of two of five mesothelioma lines. IFN alpha displayed little activity against four of five mesothelioma lines. The mesothelioma cells that were sensitive to IFN alpha were resistant to IFN gamma, indicating that sensitivity to IFNs is not a genetic characteristic of malignant mesothelioma cells. Significant interactions between cytokines in combination were not observed.

Often it is important to consider the expansion of a quantum state ⋎ ψ) in terms of physically meaningful basis states. For example, molecular orbitals can be expressed as linear combinations of atomic orbitals, or vibrational states can be expressed as super positions of local or normal mode eigenstates. In such expansions, it then becomes desirable to determine how much “character” a quantum state has in one of these basis states. One way of accimplishing this task is to calculate the projected probability of |ψ) on basis state |j). In this paper, we consider this general quantum mechanical problem. If the basis states are orthonormal, then the projected probability of|ψ) on |j) is of course | |2. However, if the basis states are not orthogonal, then this result is no longer valid and one must develop a more general theory to calculate these projected probabilities. An earlier paper used one-dimensional projection operators to initiate this theory and gave closed form results for the case of two non-orthogonal basis states [1]. One- and many-dimensional projection operators, together with linear algebraic techniques, are used to extend this theory to the n non-orthogonal basis state case. Explicit closed form results are given for the two- and three-state cases, and a general algorithm is developed for the case of four or more basis states. Application of the theory is made to atomic populations in three- to six-atom molecules, and comparisons are made to the related work of Mulliken.

The cell cycle dependence of retrovirus replication was studied. Canine sarcoma (D-17) cells were infected de novo with the xenotropic feline retrovirus RD-114 under conditions previously reported to simultaneously inhibit virus replication and cell DNA synthesis and/or cell division. RD-114 viral antigen synthesis was observed under conditions previously reported to be inhibitory to avian and murine oncornavirus replication, including confluency and serum deprivation, X-irradiation, mitomycin C pretreatment, colchicine, and ethidium bromide treatments of cells. Several mechanisms that could account for viral antigen synthesis under the restrictive conditions used are discussed.

The equilibrium trajectory of the axis of a rod subject to an externally imposed curved potential energy trough tends to conform to the shape of the curved trough, but also tends to be straight because of elastic resistance to bending. The actual path of the axis is a balance between the two extremes. We consider a potential energy trough centered along a circular arc of radius R. For a rod of small length compared to R, we show that the axis at equilibrium forms an arc of a circle of radius greater than R. The value of the radius of the axial path depends on the relative values of the Hooke's Law bending constant for the rod and the depth and width of the trough. Motivation for the calculation is provided by nucleosomal DNA, which conforms to the surface of a roughly cylindrical histone core at physiological ionic strength, but is observed to unwind into a partially extended conformation at very low ionic strength. We suggest that the rigidity to bending of short DNA segments becomes sufficiently great at low ionic strength to overcome attractive interactions with the histone surface. Alternately, of course, if during the cell cycle mutually attractive forces between DNA and histone core are weakened at constant ionic strength, the same type of unfolding would be expected to occur as the strength of the DNA-histone contacts drops below the level required to overcome elastic resistance to bending of the DNA rod.

An enzyme-linked immunosorbent assay was developed to detect antiviral IgG in the sere of sheep exposed to bluetongue virus. It was found that the enzyme-linked immunosorbent assay is a rapid and sensitive method for the detection of anti-bluetongue virus antibody. Bluetongue virus antigen prepared from extracts of virus infected BHK and Vero cells were equally effective. Antigen prepared from uninfected cells when used as coating antigen did not bind IgG from either exposed or unexposed animals. Sera raised against each of the four individual BTV serotypes, 10, 11, 13, and 17, found in the United States reacted equally with all four bluetongue virus serotype antigen preparations. Thus, any of the four serotypes can be used as the bluetongue virus antigen for the detection of anti-bluetongue virus antibody in the bluetongue virus-enzymelinked immunosorbent assay system. Antiviral IgG was readily detectable 6 days postinoculation. The anti-bluetongue virus antibody concentration continued to increase through the 35-day postinoculation test period. At 35 days postexposure, antibody titers of 1:1,600 to >1:3,200 were found. The rapid and sensitive nature of the bluetongue virus enzyme-linked immunosorbent assay indicates that this system should significantly extend serological studies on bluetongue virus.

Reduction of ZnO single particles with CO was investigated at atmospheric pressure from 1000° to 1500°C. Weight loss data up to about 90 pct reduction were easily reproducible for the dense photoconductive grade ZnO particles but not for the American grade samples, whose scatter was attributed to the 13 pct residual internal porosity and to impurities. The data agreed closely with a mixed regime model, which pictures external diffusion acting in series with an irreversible first order kinetic process at the surface. After the diffusional contribution was subtracted, activation energies of 37,900 (±2040) cal per mole and 20,600 (±10,200) cal per mole were obtained for the photoconductive and American grades, respectively. For the photoconductive grade the mixed regime model gave a good fit over the entire temperature range. Diffusional limitations were approached at 1500°C.

Hilbert and Cohn-Vossen [2, p. 221] incorrectly suggested a flexible knitting needle, constrained to conform to a surface, as one model for a geodesic on a surface. This model actually gives a relaxed elastic line on the surface, and is not generally a geodesic unless the surface lies in a plane or on a sphere. In this paper we derive the intrinsic equations for a relaxed elastic line on an oriented surface. This formulation should give a more direct and more geometric approach to questions concerning relaxed elastic lines on a surface. We apply this formulation to give alternate proofs of some results of [3] found by the less direct method of Lagrange multipliers and to give additional results about relaxed elastic lines on various surfaces. For further considerations of a relaxed elastic line on a surface as a model of the DNA molecule, see [3].

These studies indicate that the loss of skeletal muscle vascular tone following severe blood loss is not the result of a local reflex initiated by tissue ischemia.

We review and deepen a theory of elastic bending of DNA on a persistence length scale. In a regime of extensive charge neutralization the axis of the double helix is elastically unstable when straight. Its stable bent conformation allows nucleation of DNA toruses and in principle could direct the supercoiled (solenoid) form of a polynucleosome. The Euler theory of elastic instability of macroscopic rods gives a partial description of the intrinsic ability of DNA to form locally stable bends. A different, quasi-Eulerian theory can be based on what is probably the dominant bending mechanism of DNA in solution-flexible kinking at the sites of open base pairs. This predictive theory is in quantitative agreement with the observed value (about 16 nm) for the minimum radius of torus holes. Stability of the inner torus ring is achieved when DNA phosphate groups are about 90% neutralized by trivalent cations, another prediction that is consistent with the observed formation of toruses in these conditions. The predicted stable radius of curvature of charge-neutralized DNA is also equal to the radial dimension of a maximally contracted polynucleosome supercoil as measured by neutron scattering (17 nm), but further experimental investigation of the geometrical disposition of the spacer DNA regions in the solenoid will be necessary to rule out the possibility of accidental agreement for this complex system. We stress again the experimental reality and probable importance of open base pairs in the equilibrium solution conformation of DNA.