Dual-responsive, shape-switching bilayers enabled by liquid crystal elastomers.

Materials that change shape are attractive candidates to replace traditional actuators for applications with power or size restrictions. In this work, we design a polymeric bilayer that changes shape in response to both heat and water by the incorporation of a water-responsive hydrophilic polymer with a heat-responsive liquid crystal elastomer. The distinct shape changes based on stimulus are controlled by the molecular order, and consequently the anisotropic modulus, of a liquid crystal elastomer. In response to water, the hydrophilic polymer layer expands, bending the bilayer along the path dictated by the anisotropic modulus of the liquid crystal elastomer layer, which is approximately 5 times higher along the molecular orientation than in perpendicular directions. We demonstrate that by varying the direction of this stiffer axis in LCE films, helical pitch of the swollen bilayer can be controlled from 0.1 to 20 mm. By spatially patterning the stiffer axis with a resolution of 900 µm2, we demonstrate bilayers that fold and bend based on the pattern within the LCE. In response to heat, the liquid crystal elastomer contracts along the direction of molecular order, and when this actuation is constrained by the hydrophilic polymer, this contraction results in a 3D shape that is distinct from the shape seen in water. Furthermore, by using the vitrification of the dry hydrophilic polymer this 3D shape can be retained in the bilayer after cooling. By utilizing sequential exposure to heat and water, we can drive the initially flat bilayer to reversibly shift between 3D shapes.

Identification of 'hot spots' of obesity and being underweight in early pregnancy in Liverpool.

BACKGROUND: Obesity and being underweight in pregnancy are related to an increased risk of maternal and foetal morbidity, yet their prevalence is often unknown. The present study aimed to identify neighbourhoods with a higher than average prevalence or 'hot spots' of obesity and/or being underweight among first trimester pregnant women. METHODS: A database was compiled consisting of postcode, height and weight for 7981 women who had booked-in for antenatal care between July 2004 and June 2005 at Liverpool Women's Hospital. Body mass index (BMI) was calculated and women were categorised accordingly. Postcodes for 6865 cases across Merseyside were converted to geolocations (pin-points on a map) using conversion software (http://www.census.ac.uk/cdu/). RESULTS: There was a very high prevalence of being overweight (27%) and obesity (17%); 3.8% of women were underweight and probably malnourished (BMI < 18.5 kg m(-2)); and a further 10.7% of women were possibly malnourished (BMI < 20.0 kg m(-2). Deriving case density from the geolocations allowed visualisation and identification of six neighbourhoods with above average levels of obesity and three neighbourhoods had marked concentrations of both being underweight and obesity. CONCLUSIONS: These neighbourhoods, particularly those identified as 'hot spots' for both being underweight and obesity, include some of the most deprived wards in the UK. As dietetic intervention may help to promote optimal weight gain during pregnancy and improve dietary intake for pregnant women and their families, primary health care providers should target these localities with a high prevalence of low and high BMI as a priority.

Mapping dietary habits may provide clues about the factors that determine food choice.

BACKGROUND: Food deserts are thought to be a barrier to making healthier food choices. This concept has been challenged. The interaction between the physical environment and children's food choice has received little attention. The present study used food intake data to generate hypotheses concerning the role of the physical environment in food choice. METHODS: A cross-sectional analysis was conducted of the dietary habits of Year 5 (9-10-year-old) children from 90 of Liverpool's 118 primary schools. Individuals with the 'best' and 'worst' food choices were mapped and two areas associated with these extreme choices located. RESULTS: One thousand five hundred and thirty-five children completed the dietary questionnaire and supplied a full and valid postcode. Two adjacent areas with relatively large numbers of children in the 'best' and 'worst' food choice groups were chosen. Both areas had very similar socio-economic profiles. The contrast in the physical environments was striking, even on visual inspection. CONCLUSIONS: Food deserts as a cause of poor food choice did not stand scrutiny; the area located by the worst food choices had a plethora of shops selling food (better termed a food prairie), whereas the area located by the best food choices had no shops in evidence but did have more 'space'.

Effects of a signature on rates of change: a randomized controlled trial involving continuing education and the commitment-to-change model.

PURPOSE: Physicians frequently are asked to sign commitments to change practice, based upon their involvement in continuing medical education (CME) activities. Although use of the commitment-to-change model is increasingly widespread in CME, the effect of signing such commitments on rates of change is not well understood. METHOD: Immediately after a CME session, 110 physicians were asked to specify a change they intended to make in practice and to designate a level of commitment to change. To determine the effects of a signature on rates of change, physicians were randomly assigned to control (signature) and experimental (non-signature) groups. Follow-up surveys were conducted at two and three months to determine rates of change. RESULTS: In all, 88 physicians completed the first questionnaire, and 64 of them completed the follow-up. Consistent with prior studies involving the commitment-to-change model, those expressing an intention to change were significantly more likely to change on follow-up (p =.035). There was no significant difference between signature and non-signature groups (p =.99), regardless of age or gender. CONCLUSIONS: Signatures appear unimportant to assuring compliance with commitments to change used in CME conferences. A physician's behavior can be expected to change if the specified change is consistent with the physician's beliefs and sense of what is important. The relative influences of components of the commitment-to-change model require further study to determine more clearly their roles in causation and measurement.

The relation between pain beliefs, negative thoughts, and psychosocial functioning in chronic pain patients.

Cognitions and beliefs appear important in predicting adjustment to chronic pain. The current study examines how cognitions and beliefs are related to psychosocial functioning. One hundred and sixty-three chronic pain out-patients were assessed. Regression analyses were performed using scores on the Pain Beliefs and Perceptions Inventory and the Inventory of Negative Thoughts in Response to Pain as predictor variables and responses to the West Haven Yale Multidimensional Pain Inventory as criterion variables. Pain cognitions and pain beliefs were correlated. After controlling for demographics, employment status and pain severity, pain beliefs and cognitions accounted for a significant amount of the variance in general activity, pain interference, and affective distress. Negative cognitions, particularly negative self-statements, were more predictive of outcome than pain beliefs. Although these data are correlational, they provide additional support for a biopsychosocial model of adjustment to chronic pain.

Coordinate synthesis and turnover of heat shock proteins in Borrelia burgdorferi: degradation of DnaK during recovery from heat shock.

The synthesis and turnover of heat shock proteins (Hsps) by Borrelia burgdorferi, the Lyme disease spirochete, was investigated by radiolabeling of whole spirochetes and spheroplasts, comparison of one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and use of immunochemistry. The approximately 72-kDa DnaK homolog and three additional Hsps of 39, 27, and 21 kDa increased in amount by 3- to 15-fold between 2 and 6 h following temperature upshift from 28 to 39 degrees C. Temperature downshift experiments following the transfer of spirochetes from 40 to 28 degrees C showed that within 15 to 30 min, synthesis of most of the major Hsps returned to levels seen in spirochetes statically maintained at the lower temperature. Spheroplasts of B. burgdorferi produced by treatment with EDTA and lysozyme were radiolabeled, and specific Hsps were localized to either the cytoplasm or membrane fraction. Further analysis by two-dimensional electrophoresis demonstrated three constitutively expressed DnaK isoforms with pIs near 5.5. A pattern suggestive of DnaK degradation was observed following recovery from heat shock but not in spirochetes maintained entirely at a low temperature. Some of these putative degradation products were recognized by monoclonal antibodies directed against the B. burgdorferi DnaK protein. These data suggest that following a period of peak synthesis, DnaK is actively degraded as the spirochete reestablishes its metabolic thermometer. These findings provide a new interpretation of previous work suggesting that 10 to 15 B. burgdorferi polypeptides, including DnaK have a common epitope.

Molecular characterization of Pasteurella testudinis isolated from desert tortoises (Gopherus agassizii) with and without upper respiratory tract disease.

Isolates of Pasteurella testudinis recovered from clinically healthy desert tortoises (Gopherus agassizii) and tortoises with upper respiratory tract disease (URTD) were characterized in an attempt to identify strains associated with disease. Eighty-nine isolates, 52 from ill and 37 from healthy tortoises collected from Nevada (USA), June 1990 to September 1991, were genomically fingerprinted and grouped based on ribotype similarity. Twelve isolates (six from ill and six from healthy tortoises) were further characterized with regard to whole-cell protein (WCP) and outer membrane protein (OMP) composition and their ability to survive in normal tortoise plasma. The 89 isolates were initially distributed into 33 distinct ribotype groups using the restriction enzyme EcoRI; five ribotypes contained over 50% of the isolates. Only one EcoRI ribotype was comprised of multiple isolates (n = 4) exclusively recovered from tortoises with URTD. When the ten EcoRI ribotypes that contained more than one isolate per ribotype were further studied using a second restriction enzyme, EcoRV, one EcoRI/EcoRV ribotype contained five isolates recovered from URTD tortoises and none from healthy animals. The EcoRI ribotype comprised of four isolates, all from tortoises with URTD, was further separated into three distinct groups with EcoRV. All 12 isolates studied grew equally well in normal tortoise plasma, and when broth-grown WCP and OMP profiles were evaluated, no proteins were unique to isolates from URTD tortoises. Iron-regulated OMP's were produced in three isolates examined, but these OMP's apparently were not virulence-related.

Thermoregulation of protein synthesis in Borrelia burgdorferi.

Borrelia burgdorferi, the etiological agent of Lyme disease, infects humans via the bite of a tick. The microbe survives in at least two vastly different environments: an arthropod vector and a warm-blooded host. We examined protein synthesis in B. burgdorferi B31 in response to sudden heat stress, which is similar to that which occurs during the transmission from vector to host. Proteins synthesized after shifts from 28 degrees C to higher temperatures and in pulse-chase experiments were labeled with 3H-labeled amino acids for 4 h and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. The synthesis of four proteins we designated as heat stress proteins (HSPs) was increased by shifts to higher temperatures (HSP-1, 75 kilodaltons [kDa]; HSP-2, 42 kDa; HSP-3, 39 kDa; and HSP-4, 27 kDa); and the amount of one protein we designated as heat-labile protein 1 (29.5 kDa) was decreased at higher temperatures. At 37 to 40 degrees C, the major heat stress protein, HSP-1, represented 14 to 18% of the total cell protein compared with 1 to 2% of the total cell protein at 28 degrees C. HSP-1 was stable during a 4-h chase at either 40 or 28 degrees C. Demonstration of similar HSPs in low-passage, pathogenic strains of B. burgdorferi suggests that the heat stress response may be common among B. burgdorferi strains and may play a role in Lyme disease.

Computer assisted treatment planning for 125I ophthalmic plaque radiotherapy.

This paper describes a computer program for planning the treatment of ocular tumors with 125I plaques. The program permits the input of the tumor configuration into a model eye and facilitates the viewing of the relative geometry of the tumor and various eye structures in different perspectives. Custom-designed 125I plaques can be localized onto the globe, and dose distributions can be calculated and superimposed on the eye structures in any plane or on the inner eye surface. The program allows efficient evaluation of the plaque design in terms of radiation dose distribution relative to the tumor and critical structures.

Immune responses to Mycoplasma bovis vaccination and experimental infection in the bovine mammary gland.

This study characterized the immune responses in four vaccinated and four control cows in response to vaccination and experimental intramammary inoculation with Mycoplasma bovis. Specific antibody responses occurred in serum and milk in response to vaccination and experimental infection. Lymphocytes from peripheral blood, but not from the mammary gland of vaccinated cows had increased responsiveness to mitogens. No lymphocytes tested were responsive to M. bovis antigen. Both vaccination and experimental infection resulted in skin test reactivity. These results imply that vaccination results in immune responses which may alter the course of experimental M. bovis mastitis, but may contribute to cellular inflammation.

Detection of bovine serum antibody specific to Mycoplasma bovis and Mycoplasma californicum by enzyme-linked immunosorbent assay (ELISA).

ELISA for use in epidemiologic field studies of bovine mastitis, were developed to measure serum antibody to Mycoplasma bovis and M. californicum. Varying levels of serological cross-reactivity to seven heterologous bovine mycoplasmal species were demonstrated in each assay. Cross-reactivity was minimized by preincubation of cattle sera with suspensions of heterologous mycoplasma antigens, prior to measuring serum antibody to solid-phase antigen. Heterologous absorption improved the immunological specificity of the assays while avoiding the need to prepare species-unique antigens. Serum antibody was measured at one serum dilution. Test results were expressed as a ratio of the reactivity of a positive and a negative reference serum. A negative reference population (n = 127) was assembled. The percentile distribution of ELISA reactivity of these 127 sera were used to establish the classification criteria for each assay. The statistical methods used, while easily applied, were found to be sensitive to outlying values in the reference population. The resulting classification criteria provided controlled or known probabilities of false-positive misclassification in the two ELISA test systems. Sera from cattle with defined exposure histories were tested and classified according to these criteria.

Pathogenesis of bovine mycoplasma mastitis.

Most bovine mastitis due to mycoplasmas is initiated by passage of mycoplasmas through the teat canal into the teat and gland cisterns. Within a few days, mycoplasma numbers increase to as much as 10(6) or 10(8), and the cows react with a strong inflammatory response. Alveolar epithelium undergoes degenerative changes and exudate replaces milk secretion. The interstitium between alveoli is invaded with lymphocytes, macrophages, plasma cells and fibroblasts. The extent and duration of these changes vary greatly. In milder cases, they may be reversed within days or weeks with a return to normal or reduced milk production. Often, destruction and atrophy of alveoli are complete with extensive fibrosis throughout the udder. Milk ducts may undergo invasive and obliterative fibrosis. Cell-mediated responses are suppressed, while hypersensitivity is suspected of enhancing the adverse responses. Immunity in cows that recover is variable and of limited duration.

Enzyme-linked immunosorbent assay for detection of Mycoplasma californicum-specific antibody in bovine serum: optimization of assay determinants and control of serologic cross-reactions.

An enzyme-linked immunosorbent assay (ELISA) was adapted to detect Mycoplasma californicum-specific antibodies in bovine serum. Cross-reactive antibody was found in the M californicum-positive reference serum when assayed against each of 7 solid-phase antigens of heterologous mycoplasma species. Cross-reactivity was further demonstrated by inhibition of ELISA reactivity to M californicum solid-phase antigen by incubation of sera with antigen suspensions of each heterologous species. Incubation of test sera with a cross-reacting antigen mixture containing equal proportions of the 7 cross-reactive mycoplasmas was used to minimize cross-reactivity in the M californicum-specific ELISA. Specificity of antibody reactivity to M californicum, as measured by ELISA, was determined by enzyme-linked immunosorbance inhibition, in which sera were incubated with M californicum antigen suspensions before determining ELISA reactivity to M californicum solid-phase antigen. Seropositive and suspect sera (n = 55) were obtained from 3 dairies that had bacteriologically verified epizootics of M californicum mastitis. The percentage of inhibition demonstrated in enzyme-linked immunosorbance inhibition was determined for each serum. Inhibition percentages below the 15th percentile (61% inhibition) of this distribution were classified as nonspecific.

Experimental intramammary inoculation with Mycoplasma bovis in vaccinated and unvaccinated cows: effect on local and systemic antibody response.

Four cows were vaccinated with Mycoplasma bovis five times at two week intervals: three times subcutaneously in Freund's complete adjuvant, and two times with M. bovis alone in two of four quarters by intramammary infusion. The effect of vaccination on the immune response was evaluated in the serum and whey of the four vaccinated and control (placebo) cows experimentally challenged in two of four quarters with live M. bovis. Vaccination resulted in markedly increased M. bovis-specific, serum IgM, IgG and IgG2, but not IgA, reactivity. Challenge exposure with live M. bovis by intramammary infusion resulted in high specific serum IgM, IgG1 and IgG2 reactivity and a noticeable IgA response in both vaccinated and control cows. Whey from quarters on vaccinated cows had elevated, specific IgG1 reactivity at the time of challenge but no other differences were observed. Challenge exposure with live M. Bovis resulted in high antibody levels of all isotypes in quarters which were challenged, but highly elevated reactivities in unchallenged quarters occurred only with IgG1 and IgG2. These results indicate that vaccination elevated M. bovis-specific IgG1 but not other immunoglobulin reactivity in quarters on vaccinated cows, and that live organisms are necessary to elicit a local, specific IgA response.

Detecting Mycoplasma bovis in milk by enzyme-linked immunosorbent assay, using monoclonal antibodies.

Enzyme-linked immunosorbent assay, using monoclonal antibodies, was used to detect Mycoplasma bovis in milk samples from a dairy experiencing an epizootic of mastitis. This method was specific (100%) for M bovis. Broth enrichment increased the sensitivity from 65% to 86%, compared with standard culture methods.

Experimental intramammary inoculation with Mycoplasma bovis in vaccinated and unvaccinated cows: effect on the mycoplasmal infection and cellular inflammatory response.

The effect of vaccination on mycoplasmal infection and the cellular inflammatory response was evaluated in 4 vaccinated and 4 control cows experimentally challenged in 2 of 4 quarters with live Mycoplasma bovis. In unchallenged quarters during the first three weeks after experimental challenge exposure, 6 of 8 quarters on control cows, and 7 of 8 quarters on vaccinated cows became infected with low numbers (10(2)-10(4) cfu/ml) of M bovis. During the same period all challenge-infused quarters on both control and vaccinated animals became infected with high numbers (10(9) cfu/ml) of M bovis. Thereafter, all quarters on vaccinated cows became culture-negative for M bovis, while 2 of 8 unchallenged quarters, and 4 of 8 challenged quarters on 3 of 4 control cows remained infected. A cellular inflammatory response as measured by the California Mastitis Test accompanied the experimental infection in proportion to the infection level except in challenged quarters on vaccinated cows after the first three weeks post challenge in which the cellular inflammatory response remained high despite the advent of negative M bovis culture results. This study indicates that the course of experimental M bovis mastitis can be affected by vaccination, and that vaccination results in an adverse cellular inflammatory response in challenged quarters.

Experimental intramammary inoculation with Mycoplasma bovis in vaccinated and unvaccinated cows: effect on milk production and milk quality.

The effect of vaccination on milk production was evaluated in vaccinated and control cows experimentally challenged in two of four quarters with live Mycoplasma bovis. During the first three weeks after experimental challenge, six of eight unchallenged quarters on vaccinated cows and seven of eight unchallenged quarters on control cows became infected. Most of these quarters secreted normal milk, with negative California Mastitis Test scores and maintained normal milk production throughout most of the study (although some quarters on control cows remained infected). All challenged quarters became infected, had strong California Mastitis Test reactions, and had a drastic (greater than 85%) loss in milk production. Thereafter, four of eight challenged quarters on control cows remained infected, had mostly positive California Mastitis Test scores, produced mostly normal-appearing milk, and recovered some productive capabilities. By the end of the study no M. bovis could be recovered from challenged quarters on vaccinated cows and the milk appeared mostly normal. The California Mastitis Test scores on these quarters, however, remained elevated and milk production remained very low.