Near-Sun observations of an F-corona decrease and K-corona fine structure

Remote observations of the solar photospheric light scattered by electrons (the K-corona) and dust (the F-corona or zodiacal light) have been made from the ground during eclipses¹ and from space at distances as small as 0.3 astronomical units^2-5 to the Sun. Previous observations^6-8 of dust scattering have not confirmed the existence of the theoretically predicted dust-free zone near the Sun^9-11. The transient nature of the corona has been well characterized for large events, but questions still remain (for example, about the initiation of the corona¹² and the production of solar energetic particles¹³) and for small events even its structure is uncertain¹⁴. Here we report imaging of the solar corona¹⁵ during the first two perihelion passes (0.16-0.25 astronomical units) of the Parker Solar Probe spacecraft¹³, each lasting ten days. The view from these distances is qualitatively similar to the historical views from ground and space, but there are some notable differences. At short elongations, we observe a decrease in the intensity of the F-coronal intensity, which is suggestive of the long-sought dust free zone^9-11. We also resolve the fine-scale plasma structure of very small eruptions, which are frequently ejected from the Sun. These take two forms: the frequently observed magnetic flux ropes^12,16 and the predicted, but not yet observed, magnetic islands^17,18 arising from the tearing-mode instability in the current sheet. Our observations of the coronal streamer evolution confirm the large-scale topology of the solar corona, but also reveal that, as recently predicted¹⁹, streamers are composed of yet smaller substreamers channelling continual density fluctuations at all visible scales.

A loop-mediated isothermal amplification method for rapid direct detection and differentiation of nonpathogenic and verocytotoxigenic Escherichia coli in beef and bovine faeces

AIM

To develop a multiplex loop-mediated isothermal amplification (LAMP) assay capable of quantifying Escherichia coli and differentiating verocytotoxigenic E. coli (VTEC).

METHODS AND RESULTS

Primer sets were selected to amplify the phoA gene (all E. coli strains) and stx1 and/or stx2 genes (VTEC strains only). LAMP calibration curves demonstrated good quantification capability compared with conventional culture. The limits of detection 50% (LOD₅₀ ) of the multiplex LAMP assay were 2·8 (95% CI 2·4-3·3), 3·2 (95% CI 2·5-3·9) and 2·8-3·2 (95% CI 2·1-3·5) log CFU per g for the phoA, stx1 and stx2 genes, respectively. When validated by testing retail beef and bovine faeces samples, good correlation between E. coli counts indicated by the LAMP assay and culture was observed; however, false-negative LAMP assay results were obtained for 12·5-14·7% of samples.

CONCLUSIONS

A rapid, multiplex LAMP assay for direct quantification of E. coli and specific detection of VTEC in beef and faeces was successfully developed. Further optimisation of the assay would be needed to improve detection sensitivity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The multiplex LAMP assay represents a rapid alternative to culture for monitoring E. coli levels on beef for hygiene monitoring purposes, and, potentially, a method for detection of VTEC in beef and faeces.

A contribution to the discussion on the safety of air weapons

Firearms legislation in the UK stems from the Firearms Act 1968 with its definition of a firearm as a lethal barrelled weapon of any description. The Act allows certain exceptions to be held without licence, most notably air weapons although these are limited by The Firearms (Dangerous Air Weapons) Rules 1969 and related regulations to below 12ft lb (16.3J) for air rifles and below 6ft lb (8.1J) for air pistols. Despite this there are occasional fatalities, typically 1 or 2 each year in the UK, from legally owned air weapons. In the USA there are over 20,000 visits each year to emergency departments due to injuries from air weapons and paintball guns. Despite this, limited research appears to have been carried out into the safety of air weapons and the present study tries to address this. Fresh samples of animal tissue were obtained from an abattoir or butcher and were embedded in ballistic gelatin. Pig heart, lung, liver and shoulder were used. By firing pellets into gelatin alone and into the combination of the gelatin and animal tissue it was possible to compare gelatin as a model for these tissues. The depth of penetration was similar but the residual track appeared to remain more open in the animal tissue. Pellets penetrated completely through the organ, with total penetration of gelatin and organ being typically around 10-15cm. Samples of pig, cow and chicken skin were placed in contact with the gelatin or embedded in the gelatin to simulate the effect of skin on penetration into a body. Chicken skin had no effect, pig skin stopped the pellet and cow skin was perforated by the pellet. If cow skin was embedded in the gelatin there was little effect on the total amount of penetration, but cow skin on the front surface of the gelatin reduced penetration by about 30%. Computed tomography was used to examine the pellet track and to calculate the volume of damage produced. However, due to the similar densities of gelatin and organ a technique had to be developed to differentiate phases. A barium salt paste was applied to outer surfaces and iodine solution or barium nitrate solution containing red food colouring was injected into the pellet track to enhance the contrast of the track. The track through the gelatin tended to enclose itself whereas the track through the organ remained more open, presumably due to the inhomogeneity of the fibrous nature of the tissue. Pellets were also fired at construction materials (wood, plasterboard and brick) and computed tomography used to determine the volume of damage created. Pellets perforated single layers of wood and plasterboard and would embed in a second layer. However, if the two layers were in contact the pellet did not penetrate the first layer. An air rifle pellet could therefore perforate house construction materials, although the resultant kinetic energy would be low and further damage would be limited. Some of the possible physical parameters are discussed that might help predict the degree of damage caused, but from this study it is not possible to define a limit which could be proposed as safe.

The combined effects of high pressure and nisin on germination and inactivation of Bacillus spores in milk

AIMS

The aim of this work was to investigate the germination and inactivation of spores of Bacillus species in buffer and milk subjected to high pressure (HP) and nisin.

METHODS AND RESULTS

Spores of Bacillus subtilis and Bacillus cereus suspended in milk or buffer were treated at 100 or 500 MPa at 40 degrees C with or without 500 IU ml(-1) of nisin. Treatment at 500 MPa resulted in high levels of germination (4 log units) of B. subtilis spores in both milk and buffer; this increased to >6 logs by applying a second cycle of pressure. Viability of B. subtilis spores in milk and buffer was reduced by 2.5 logs by cycled HP, while the addition of nisin (500 IU ml(-1)) prior to HP treatment resulted in log reductions of 5.7 and 5.9 in phosphate buffered saline and milk, respectively. Physical damage of spores of B. subtilis following HP was apparent using scanning electron microscopy. Treating four strains of B. cereus at 500 MPa for 5 min twice at 40 degrees C in the presence of 500 IU ml(-1) nisin proved less effective at inactivating the spores of these isolates compared with B. subtilis and some strain-to-strain variability was observed.

CONCLUSIONS

Although high levels of germination of Bacillus spores could be achieved by combining HP and nisin, complete inactivation was not achieved using the aforementioned treatments.

SIGNIFICANCE AND IMPACT OF THE STUDY

Combinations of HP treatment and nisin may be an appealing alternative to heat pasteurization of milk.

Effect of high pressure and pasteurization on Mycobacterium avium ssp. paratuberculosis in milk

AIMS

To determine the effect of high pressures alone and in conjunction with pasteurization on the viability of two strains of Mycobacterium avium ssp. paratuberculosis (Map).

METHODS AND RESULTS

Map in a milk matrix was subjected to 400, 500 and 600 MPa with and without pasteurization (72 degrees C for 15 s) and plated onto Herrold's egg yolk medium (HEYM) and Middlebrook 7H10 (7H10) agar, both containing antibiotic supplements. Medium 7H10 was found to give a significantly (P < 0.001) better recovery than HEYM. A significantly greater (P < 0.001) reduction in viable numbers was observed using 500 MPa (mean log reduction of 6.52) compared with 400 MPa (mean log reduction of 2.56) and between 400 MPa and control (no applied pressure) for 10 min treatments. A treatment time of 10 min resulted in significantly (P < 0.001) fewer survivors than 5 min. Low numbers of survivors were still detected when pressure treatment at 400 and 600 MPa was combined with subsequent pasteurization.

CONCLUSIONS

The use of high-pressure was effective in reducing viable numbers of Map but even when combined with pasteurization there were still survivors, albeit when high inoculum levels of Map were used.

SIGNIFICANCE AND IMPACT OF THE STUDY

To the authors' knowledge the work reported here represents the first study of the efficacy of high-pressure treatments alone and in combination with pasteurization to kill Map. The results indicate that further research is warranted before more commercial-scale studies are commissioned.

Correlated motion and oscillation of neighboring cells in vitro

It has long been realized that fibroblastic and epithelial cells establish recognizable patterns in tissue culture. This behavior implies that neighboring cells interact with one another to produce organized populations. Interaction between cells that are separated by many intervening cells is also possible and is demonstrated here using a special configuration of a biosensor referred to as electric cell-substrate impedance sensing (ECIS). Normally the electrical impedance of a single electrode covered with a confluent cell layer is measured, and the morphological changes of the cells are reflected in the impedance. In this case the cells are cultured on two closely spaced electrodes whose impedances are measured independently as a function of time, and communication between the cell populations is revealed as a correlation between these two time series. We also report for the first time another striking manifestation of dynamic cell interaction, where confluent layers of Madin-Darby canine kidney cells (MDCK) on a single electrode are observed to oscillate in synchrony with a period of approximately 2.5 h.

The effect of growth stage and growth temperature on high hydrostatic pressure inactivation of some psychrotrophic bacteria in milk

The effect of high hydrostatic pressure on the survival of the psychrotrophic organisms Listeria monocytogenes, Bacillus cereus, and Pseudomonas fluorescens was investigated in ultrahigh-temperature milk. Variation in pressure resistance between two strains of each organism were studied. The effect of growth stage (exponential and stationary phase), growth temperature (8 and 30 degrees C) on pressure resistance, and sublethal pressure injury were investigated. Exponential-phase cells were significantly less resistant to pressure than stationary-phase cells for all of the three species studied (P < 0.05). Growth temperature was found to have a significant effect at the two growth stages studied. Exponential cells grown at 8 degrees C were more resistant than those grown at 30 degrees C, but for stationary-phase cells the reverse was true. B. cereus stationary-phase cells grown at 30 degrees C were the most pressure resistant studied. L. monocytogenes showed the most sublethal damage compared to B. cereus and P. fluorescens. B. cereus spores were more resistant to pressure than vegetative cells. Pressure treatment at 400 MPa for 25 min at 30 degrees C gave a 0.45-log inactivation. Pressure treatment at 8 degrees C induced significantly less spore germination than at 30 degrees C. This study indicates the importance of the history of a bacterial culture prior to pressure treatment and that bacterial spores require more severe pressure treatments, probably in combination with other preservation techniques, to ensure inactivation.

High pressure processing of foods for microbiological safety and quality (a short review)

Consumers are demanding foods that are "natural", of good nutritional and sensory quality, free from chemical preservatives, microbiologically safe and with extended shelf-life. High pressure processing can, potentially, meet these criteria. Recent advances in equipment design now allow foods to be processed up to 900 MegaPascals (130,000 psi). However, further work is required to more fully understand the factors that can affect the response of microorganisms, including pathogens, to pressure so that treatments can be optimised and microbiological safety can be assured. This paper describes how the pressure resistance of microorganisms can vary depending on factors such as species, strain, stage of growth and food composition. Strategies for overcoming the problem of pressure resistance will be discussed, for example the use of pressure cycling and the combination of pressure with mild heat. The current commercial uses of high pressure to preserve foods will be reported and potential applications will also be discussed.

Survival of Escherichia coli O157:H7 during storage in pressure-treated orange juice

The effect of a high-pressure treatment on the survival of a pressure-resistant strain of Escherichia coli O157:H7 (NCTC 12079) in orange juice during storage at 3 degrees C was investigated over the pH range of 3.4 to 5.0. The pH of shelf-stable orange juice was adjusted to 3.4, 3.6, 3.9, 4.5, and 5.0 and inoculated with 10(8) CFU ml(-1) of E. coli O157:H7. The orange juice was then pressure treated at 400 MPa for 1 min at 10 degrees C or was held at ambient pressure (as a control). Surviving E. coli O157:H7 cells were enumerated at 1-day intervals during a storage period of 25 days at 3 degrees C. Survival of E. coli O157:H7 during storage was dependent on the pH of the orange juice. The application of high pressure prior to storage significantly increased the susceptibility of E. coli O157:H7 to high acidity. For example, after pressure treatment, the time required for a 5-log decrease in cell numbers was reduced from 13 to 3 days at pH 3.4, from 16 to 6 days at pH 3.6, and from >25 to 8 days at pH 3.9. It is evident that the use of high-pressure processing of orange juice in order to increase the juice's shelf-life and to inactivate pathogens has the added advantage that it sensitizes E. coli O157:H7 to the high acid conditions found in orange juice, which results in the survival of significantly fewer E. coli O157:H7 during subsequent refrigerated storage.

Inactivation of Escherichia coli O157:H7 in orange juice using a combination of high pressure and mild heat

The effect of high pressure on the survival of a pressure-resistant strain of Escherichia coli O157:H7 (NCTC 12079) in orange juice was investigated over the pH range 3.4 to 5.0. The pH of commercial, sterile orange juice was adjusted to 3.4, 3.6, 3.9, 4.5, or 5.0. The juice was then inoculated with 10(8) CFU ml(-1) of E. coli O157:H7. The inoculated orange juice was subjected to pressure treatments of 400, 500, or 550 MPa at 20 degrees C or 30 degrees C to determine the conditions that would give a 6-log10 inactivation of E. coli O157:H7. A pressure treatment of 550 MPa for 5 min at 20 degrees C produced this level of kill at pH 3.4, 3.6, 3.9, and 4.5 but not at pH 5.0. Combining pressure treatment with mild heat (30 degrees C) did result in a 6-log10 inactivation at pH 5.0. Thus, the processing conditions (temperature and time) must be considered when pressure-treating orange juice to ensure microbiological safety.

Designing an effective counteradvertising campaign--Arizona

In this report, the authors describe an innovative antitobacco advertising campaign in Arizona that was aimed at youth. The campaign utilizes traditional as well as non-traditional methods of research to determine the attitudes, behavior and values of today's adolescents. These creative methodologies led to rigorously tested and well-received media strategies.

Nursing Assistance for Families of Patients

With deinstitutionalization, families have become the primary caregivers of persons with mental illness. Mental health professionals and family members must work together to prevent damage to our most valuable resource, the family. Nurses, who often provide the most continuous care for seriously mentally ill persons, are in a unique position to reach out to families and provide the help that they need as primary caregivers. Let us not fail our patients or their families.

A New Equilibrium Model for the Bazarov Urea Synthesis Process

A new equilibrium model for the high temperature and pressure Bazarov urea synthesis process is presented. By including the formation of ammonium hydroxide as an important equilibrium in the process the model can quantitatively predict the yield of urea under the following range of synthesis conditions: NH3/C02 ratios (L) greater than 2, when no excess water is added, in the temperature range 170-210�C. The model also predicts the observed maximum in urea yield with temperature for a given L> 2. New experimental data for L> 9 are presented that confirm the model's prediction that the yield of urea asymptotically approaches 100% at high L ratios. These data also reveal a pressure dependence for the urea yields which becomes more pronounced with increasing temperature and L ratio. In this region the agreement between theory and experiment is generally within 3% in the pressure range 30-50 MPa. Enthalpies of reaction for the formation of urea from ammonium carbamate and for the formation of ammonium hydroxide under urea synthesis conditions have been derived, and are 26 and -40 kJ mol-1 respectively, the former being in good agreement with a value estimated from literature data.

Caesarean section: a national study

Although the use of caesarean section (CS) continues to be debated, the demographic characteristics of the affected population have received little attention. This paper shows that in New Zealand during 1983-84, a CS was performed on 9.6% of delivered women between the ages of 15-44. The rate increased with maternal age (p less than 0.01), and was highest for 'single' women (11.3/100) and Pacific Island women aged 35-44 (21/100). There was a significantly (p less than 0.05) high rate in the Auckland and South Otago hospital board districts, but a low rate (p less than 0.05) in the Ashburton, Nelson, Canterbury, Southland, Taumaranui, Waiapu, Wairarapa, Wanganui, and Wellington board districts. The rate was also high (p less than 0.01) in the principal teaching hospitals. Long labour (15.2%), malposition and malpresentation of the fetus (14.7%) were the leading reasons for performing a CS. The paucity of national data on a number of other highly relevant birth and maternal factors hinders the further definition of the epidemiological patterns of CS in New Zealand.

Comparison of the use of reserpine versus alpha-methyldopa for second step treatment of hypertension in the elderly

A retrospective chart analysis was conducted on all new elderly hypertensive patients referred to a community hypertension clinic who were being treated with either reserpine or alpha-methyldopa plus a diuretic. There were no significant differences between the two groups on entry in age, gender, co-morbid diagnoses, or systolic or diastolic blood pressure. There were no significant differences between the two groups in terms of side effects over three years, but the proportion of persons having compliance problems was significantly lower in the reserpine group. Mean diastolic pressures were significantly lower after one, two, and three years, and systolic pressures were lower after one and two years in the reserpine group. Reserpine is at least as effective as alpha-methyldopa in treating hypertension in the elderly and is associated with fewer problems in compliance.

High-pressure photodimerization of a naphthalene derivative

An applied pressure of 2000 bars (1 bar = 105 Pa ≡ 0.9869 atm) has been found to double the rate of photodimerization of methyl 3-methoxy-2- naphthoate in solution in toluene and in methanol at 20°C. The acceleration corresponds to an average activation volume between 1 and 2000 bars of ΔV‡av ≈ -10 cm3 mol-1, and is much less than the known acceleration, under similar conditions, of analogous thermal reactions.

Influence of pressure on the rates of deuteration of formate and acetate ions in liquid D2O

We have examined the effects of hydrostatic pressures to 8 kbar on the rates of deuteration of formate and acetate ions in pure D2O at temperatures between 160 and 200�C. The formate reaction is only slightly accelerated by pressure (the activation volume ΔVo?, at zero pressure, is -2.5 cm3 mol-1). This fact disproves mechanisms that have been proposed previously for the reaction and we propose an alternative, concerted, molecular mechanism that fits the facts. By contrast, the acetate reaction is significantly accelerated by pressure (ΔVo? = -10.5 cm3 mol-1), which is consistent with its occurring by mixed molecular and carbanionic mechanisms.

The influence of pressure on the infrared spectra of hydrogen-bonded solids. IV. Miscellaneous compounds

Measurements have been made of the influence of pressure on the stretching and bending frequencies of hydrogen bonds in a further series of 15 solid compounds. Two exceptions have been found tothe general rule that an increase of pressure decreases the X-H stretching frequencies of weak and medium-strength X-H....Y bonds. Possible explanations are offered of the exceptions.

The influence of pressure on the infrared spectra of hydrogen bonded solids. II. Bihalide salts

Infrared measurements have been made of the influence of pressures between 0 and 40 kbar on the asymmetrical stretching frequencies v3 and bending frequencies v2 of the hydrogen-bonded ions FHF- and ClHCl- in the solid salts NaHF2, KHF2, NH4HF2, (CH3)4NHCl2 and (C2H5)4NHCl2 at 25�C. The behaviour of the symmetrical stretching frequency v1 for FHF- in KHF2 has been deduced indirectly from the shifts of combination bands. Contrary to the behaviour of compounds with weaker, 'normal', hydrogen bonds, the v3 bands shift to higher frequencies and the v2 bands shift to lower frequencies with increasing pressure. The vl band of KHF2 shifts to higher frequencies. These trends are all in agreement with predictions made in Part I for a simple model of hydrogen bonds. A new high-pressure phase transition has been found to occur in NaHF2 at about 40 kbar.

The influence of pressure on the infrared spectra of hydrogen-bonded solids. III. Compounds with N-H...X bonds

Infrared measurements have been made of the influence of pressures between 0 and 40 kbar on the stretching and bending frequencies of N-H groups in a range of crystalline compounds which have N-H. . .N, N-H. . .O, N-H. . .S or N-H. . .Cl hydrogen bonds. The frequencies have been found to change in accordance with rules that were derived and tested in Parts I and I1 for other kinds of hydrogen-bond systems.

The influence of pressure on the electronic absorption spectra of some aromatic molecules and ions

Measurements have been made of the effects of raising the pressure from 1 bar to 2000 bar on the frequencies and intensities of the low frequency electronic absorption bands of 57 aromatic molecules and ions in aqueous solution at 25�C. For comparison, measurements have also been made of frequency shifts produced by changing the solvent from water to ethanol at atmospheric pressure. ��� A remarkable feature of the results is that although compression raises the dielectric constant and refractive index of water, it produces red frequency shifts (shifts to lower frequencies) in the n → π* bands of molecules. These bands are well known to undergo blue shifts when one solvent is changed to another of higher polarity at atmospheric pressure. The apparent anomaly can be explained in terms of McRae's theory of frequency shifts, as arising from a decrease, with increasing pressure, of the energy of interaction between permanent dipoles of the solvent and of the absorbing molecules. The π → π* absorption bands of molecules generally show red shifts with both increasing pressure and increasing solvent polarity: this result is also consistent with McRae's theory. The absorption bands of most of the ions show blue shifts which can be explained by charge delocalization in the excited states. The intensity changes are in general agreement with the predictions of current theories of oscillator strengths in solution. �� The results provide indirect evidence of the influence of pressure on the ionization constants of excited states of phenols.

The influence of pressure on the infrared spectra of hydrogen-bonded solids. I. Compounds with O-H - - - O bonds

Measurements have been made of the influence of pressures up to 40 kbar on the hydrogen-bonded OH stretching and bending frequencies of a series of solids whose hydrogen bonds cover the full range of strengths from very weak to very strong. The bending frequencies all increase with increasing pressure, and the stretching frequencies nearly all decrease. The exceptions to this general pattern are shown by compounds with strong, symmetrical, hydrogen bonds, whose stretching frequencies increase with increasing pressure. This reversal of behaviour is consistent with the predictions of a simple model based on Lippincott and Schroeder's empirical potential energy function for hydrogen bonds.

Solid-phase polymerizations at high pressures

The following compounds have been found to polymerize spontaneously in the solid state at pressures in the range 10-50 kbar, at temperatures between 20 and 200�C: acrylamide, p-phenylstyrene, potassium p-styrenesulphonate, itaconic anhydride, maleic anhydride, maleimide, 1,2,3,6-tetrahydrophthalic acid, 1,2,3,6-tetrahydrophthalic anhydride, acenaphthylene, p-benzoquinone, N,N'-p-phenylene-dimaleimide, sulpholene, diphenylacetylene, 8-trioxan. The pressure-temperature requirements for polymerization have been determined in a high-pressure "squeezer" apparatus and in a diamond optical cell which permits infrared spectral analysis of a specimen while it is under compression. Apart from diphenylacetylene and trioxan, the compounds that polymerized were either monosubstituted ethylenes or cyclic 1,2-disubstituted ethylenes. Non-cyclic 1,2-disubstituted ethylenes and tri-substituted and tetra-substituted ethylenes failed to polymerize. There is evidence that shearing stresses played a part in some of the reactions. 1-Allyl-2-thiourea did not polymerize, but transformed from its stable crystal form I to the unstable modification 11.