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Strong seasonal trends in reproduction and early development of many invasive species are commonplace and may differ between introduced and native ranges, reflecting differences in abiotic conditions that trigger reproduction, or in selective pressures. The invasive crab Carcinus maenas has been present in south-east Australia for over 100 years, but little is known about its recruitment to benthic substrates in this introduced range. This study assessed the timing of C. maenas and native crab recruitment to Merimbula Lake (36.89oS, 149.92oE) south-eastern Australia between August 2011 and October 2013. It also assessed the effectiveness of four different types of recruitment bags for detecting the invasive crab. Carcinus maenas recruited in greater numbers to bags that contained live oysters than those with oyster shell, artificial turf or without structure. Recruitment of C. maenas peaked in the late winter and spring, while recruitment of most native species peaked in autumn. The timing of C. maenas recruitment contrasted its native European range where recruitment typically occurs in summer and autumn. Although likely triggered by the warmer water temperatures of south-eastern Australia, this differing reproductive phenology of C. maenas between its native and Australian range may also modify its interactions with native crab recruits.

There is growing interest in associations between non-native species and native foundation species. Along the southeast coast of Australia, the European shore crab, Carcinus maenas , overlaps with the distribution of the grey mangrove, that provides refuge to many native invertebrates from predators and physiological stress. We tested the hypothesis that C. maenas would be more abundant under the canopy of mangrove forests than in adjacent unvegetated intertidal habitat. Trapping surveys within three estuaries found greater abundances of C. maenas in mangrove forests than in adjacent unvegetated habitat and, within mangrove forests, under the canopy than in the pneumatophores zone. Average temperatures under the mangrove canopy were up to 2 °C lower than in unshaded habitats and maximum temperatures up to 5.7 °C less. The results of tethering studies did not support the hypothesis that predatory mortality of C. maenas was reduced in mangroves. To the contrary, survivorship of tethered crabs was much lower under the mangrove canopy than in adjacent unvegetated habitat. Habitat choice experiments, however, indicated that crabs chose shaded and protected over unshaded and exposed habitat. Hence, along this coastline where summertime maximum air temperatures may approach the known LD 50 of C. maenas (40 min at 40 °C), mangroves may help to facilitate persistence in intertidal habitats. Our study adds to a growing number indicating that foundation species may not only facilitate native species, but non-native species too. Additional studies are now needed to confirm the mechanism of the association between C. maenas and mangroves in eastern Australia.

Following the arrival of non-native species into suitable environments, interactions with native biota can influence non-native species proliferation and spread. The European shore crab, Carcinus maenas, is a global invader for which top-down control by predators has been implicated in limiting range expansion in its North American range. Little is known, however, about predators of this non-native species within its Australian distribution. We conducted quarterly trapping over 2 years in ten Australian estuaries to assess relationships between the abundance of C. maenas and native predators. Feeding assays between C. maenas and putative predators, identified from negative associations in occurrence, assessed the ability of putative predators to recognise C. maenas as prey. Six taxa were negatively correlated with C. maenas’ abundance and capable of eating the non-native crab. These were the blue swimmer crab (Portunus pelagicus), octopods (Octopus spp.), leatherjackets (Monocanthidae), yellowfin bream (Acanthopagrus australis), toadfish (Tetraodontidae) and the eastern fiddler ray (Trygonorrhina fasciata). Octopus spp. were rare in and blue swimmer crabs absent from mangroves; the habitat in which C. maenas was most abundant. A tethering experiment confirmed that Octopus spp. eat C. maenas in the field, with greater rates of mortality of the crab close to than away from the Octopus spp. lairs. Overall, our study indicates that a diverse assemblage of predators may prey upon C. maenas in southeastern Australia. Further studies assessing relative rates of predation by these predators on C. maenas are needed to assess whether they are exerting significant top-down control.

Most incidences of basal cell carcinoma are cured by a number of surgical or non-surgical treatments. However, a few patients have lesions which have metastasized or progressed to an extent that surgery or other treatment options are not possible. The lesions associated with advanced basal cell carcinoma (aBCC) can be disfiguring, affecting patients' psychological state, general quality-of-life (QoL), and potentially life expectancy. The objective of this study was to capture societal utility values for health states related to aBCC, using the time trade-off (TTO) methodology.Nine health states were developed with input from expert clinicians and literature. States included: complete response (CR), post-surgical, partial response (PR) (with differing sized lesions [2 or 6 cm]), stable disease (SD) (with differing size and number of lesions [2 or 6 cm, or multiple 2 cm]) and progressive disease (PD) (with differing sized lesions [2 or 6 cm]). A representative sample of 100 members of the UK general public participated in the valuation exercise. The TTO method was used to derive utility values based upon subjects' responses to decision scenarios; between living in the health state for 10 years or living in a state of full health for 10-x years.Mean utility scores were calculated for each state. The least burdensome state as valued by subjects was CR (mean = 0.94; SD = 0.08), suggesting only a minimal impact on QoL. The state valued as having a greatest impact on QoL was PD, with a 6 cm lesion (mean = 0.67, SD = 0.25).Not all possible presentations of aBCC were included; the disease is a challenging condition to characterise given its rarity, the nature of the patients affected, and its variable progression. Findings suggest that aBCC is associated with significant burden for individuals, even when their disease is stable or where surgical treatment has been successful.

Today almost a quarter of all neutron scattering experiments performed at neutron scattering facilities require sample temperatures below 2 K. However, a global shortage of helium gas can seriously jeopardise low temperature experimental programmes at neutron scattering laboratories. Luckily the progress in cryo-cooler technology offers a new generation of cryogenic systems with significantly reduced consumption and in some cases nearly a complete elimination of cryogens. Here we discuss design and test results of a new cryogen free top-loading cryostat developed through an ISIS and Oxford Instruments collaborative project. The cryostat provides neutron scattering sample environment in the temperature range 1.4–300 K. High cooling power (0.23 W at temperature less than 2 K) achieved at the cryostat’s variable temperature insert heat exchanger allows operation of a standard dilution refrigerator insert in a continuous regime. From a user perspective, the system offers operating parameters very similar to those of an Orange cryostat but without the complication of cryogens.

The distribution of Cenozoic ash-flow tuffs in the Great Basin and the Sierra Nevada of eastern California (United States) demonstrates that the region, commonly referred to as the Nevadaplano, was an erosional highland that was drained by major west- and east-trending rivers, with a north-south paleodivide through eastern Nevada. The 28.9 Ma tuff of Campbell Creek is a voluminous (possibly as much as 3000 km 3 ), petrographically and compositionally distinctive ash-flow tuff that erupted from a caldera in north-central Nevada and spread widely through paleovalleys across northern Nevada and the Sierra Nevada. The tuff can be correlated over a modern area of at least 55,000 km 2 , from the western foothills of the Sierra Nevada to the Ruby Mountains in northeastern Nevada, present-day distances of ∼280 km west and 300 km northeast of its source caldera. Corrected for later extension, the tuff flowed ∼200 km to the west, downvalley and across what is now the Basin and Range–Sierra Nevada structural and topographic boundary, and ∼215 km to the northeast, partly upvalley, across the inferred paleodivide, and downvalley to the east. The tuff also flowed as much as 100 km to the north and 60 km to the south, crossing several east-west divides between major paleovalleys. The tuff of Campbell Creek flowed through, and was deposited in, at least five major paleovalleys in western Nevada and the eastern Sierra Nevada. These characteristics are unusual compared to most other ash-flow tuffs in Nevada that also flowed great distances downvalley, but far less east and north-south; most tuffs were restricted to one or two major paleovalleys. Important factors in this greater distribution may be the great volume of erupted tuff and its eruption after ∼3 Ma of nearly continuous, major pyroclastic eruptions near its caldera that probably filled in nearby topography. Distribution of the tuff of Campbell Creek and other ash-flow tuffs and continuity of paleovalleys demonstrates that (1) the Basin and Range–Sierra Nevada structural and topographic boundary did not exist before 23 Ma; (2) the Sierra Nevada was a lower, western ramp to the Nevadaplano; and (3) any faulting before 23 Ma in western Nevada, including in what is now the Walker Lane, and before 29 Ma in northern Nevada as far east as what is now the Ruby Mountains metamorphic core complex, was insufficient to disrupt the paleodrainages. These data are further evidence that major extension in Nevada occurred predominantly in the late Cenozoic. Characteristics of paleovalleys and tuff distributions suggest that the valleys resulted from prolonged erosion, probably aided by the warm, wet Eocene climate, but do not resolve the question of the absolute elevation of the Nevadaplano. Paleovalleys existed at least by ca. 50 Ma in the Sierra Nevada and by 46 Ma in northeastern Nevada, based on the age of the oldest paleovalley-filling sedimentary or tuff deposits. Paleovalleys were much wider (5–10 km) than they were deep (to 1.2 km; greatest in western Nevada and decreasing toward the paleo–Pacific Ocean) and typically had broad, flat bottoms and low-relief interfluves. Interfluves in Nevada had elevations of at least 1.2 km because paleovalleys were that deep. The gradient from the caldera eastward to the inferred paleodivide had to be sufficiently low so that the tuff could flow upstream more than 100 km. Two Quaternary ash-flow tuffs where topography is nearly unchanged since eruption flowed similar distances as the mid-Cenozoic tuffs at average gradients of ∼2.5–8 m/km. Extrapolated 200–300 km (pre-extension) from the Pacific Ocean to the central Nevada caldera belt, the lower gradient would require elevations of only 0.5 km for valley floors and 1.5 km for interfluves. The great eastward, upvalley flow is consistent with recent stable isotope data that indicate low Oligocene topographic gradients in the Nevadaplano east of the Sierra Nevada, but the minimum elevations required for central Nevada are significantly less than indicated by the same stable isotope data. Although best recognized in the northern and central Sierra Nevada, early to middle Cenozoic paleodrainages may have crossed the southern Sierra Nevada. Similar early to middle Cenozoic paleodrainages existed from central Idaho to northern Sonora, Mexico, and persisted over most of that region until disrupted by major Middle Miocene extension. Therefore, the Nevadaplano was the middle part of an erosional highland that extended along at least this length. The timing of origin and location of this more all-encompassing highland indicates that uplift was predominantly a result of Late Cretaceous (Sevier) contraction in the north and a combination of Late Cretaceous–early Cenozoic (Sevier and Laramide) contraction in the south.

A survey of Listeria in ready-to-eat food took place in Wales, United Kingdom, between February 2008 and January 2009. In total, 5,840 samples were taken and examined for the presence of Listeria species, including L. monocytogenes. Samples were tested using detection and enumeration methods, and the results were compared with current United Kingdom guidelines for the microbiological quality of ready-to-eat foods. The majority of samples were negative for Listeria by both direct plating and enriched culture. Seventeen samples (0.29%) had countable levels of Listeria species (other than L. monocytogenes), and another 11 samples (0.19%) had countable levels of L. monocytogenes. Nine samples (0.15%) were unsatisfactory or potentially hazardous when compared with United Kingdom guideline limits; six (0.10%) were in the unsatisfactory category (>100 CFU/g) for Listeria species (other than L. monocytogenes), and three (0.05%) were in the unacceptable or potentially hazardous category (>100 CFU/g) for L. monocyt...

A survey of the general microbiological quality of ready-to-eat food served in schools was undertaken across Wales, United Kingdom. Of the 2,351 samples taken, four were identified as containing unsatisfactory counts of Escherichia coli, four contained unsatisfactory counts of Staphylococcus aureus, and one contained an unacceptable count of Bacillus cereus when compared with guidelines for the microbiological quality of ready-to-eat food published by the United Kingdom Public Health Laboratory Service in 2000. No samples contained detectable levels of Salmonella, Listeria species, or Clostridium perfringens. When compared with data on the general microbiological quality of food available in Wales, the food sampled from schools was of relatively better microbiological quality.

In the reaction between solid oxalic acid and aqueous borax solution, product boric acid precipitates in the solution phase after complete dissolution of oxalic acid crystals. This makes it possible to measure the dissolution and precipitation kinetics independently. The oxalic acid dissolution process was found to be diffusion controlled. Nucleation rates of product boric acid were influenced by heterogeneous primary nucleation and secondary nucleation, while growth rates were affected by both the bulk diffusion and surface integration processes. Dissolution of oxalic acid ctystals was described by a surface reaction model, and overall nucleation and growth rates were correlated in terms of the influencing process variables. Simulation analysis was carried out by linking the two processes of dissolution and precipitation in series. The trends of the predicted supersaturation profiles, number concentration, magma density and mean size of the product crystals are in good agreement with measured values.

To make rapid progress in manufacturing business processes have to be rigorously designed by teams of people with a passion for how they will operate. Businesses are dependent on operating systems, but many companies have never designed the fundamental business processes defining how the company will perform the various tasks. This paper examines the structure of manufacturing companies and outlines the fundamental business processes needed to make them operate effectively. At a conceptual level, considerable similarities exist in the core processes required to manage businesses and differences are a function of specific business activities linked to the tasks that have to be performed. The basic message of this paper is that, to make rapid progress in manufacturing, process must be designed. This is a demanding management task impacting the way people work together throughout an organization, but a company without an operating system, like a computer, has little chance of producing the required results. If competitors have designed and implemented cost-effective processes why should a particular business be expected to be successful using traditional methods developed by custom and practice?

(1999). Geology of Nevada With excellent rock exposures in the desert, generally good access to collecting localities on public lands, and fine tourist attractions in the towns, Nevada is a wonderful state for rock and mineral enthusiasts. Rocks & Minerals: Vol. 74, No. 6, pp. 357-363.

The cDNA encoding the [His5Trp7Tyr8] gonadotropin-releasing hormone (chicken-II-type GnRH; cGnRH-II) precursor from rainbow trout Oncorhynchus mykiss has been sequenced using reverse transcription and rapid amplification of cDNA ends (RACE). The precursor cDNA is 544 bp from which an open reading frame of 258 bases encodes a 86 amino acid precursor. The tripartite structure of the encoded peptide is identical to all other GnRHs reported to date. The rainbow trout cGnRH-II cDNA, including both the precursor encoding and non-coding regions, shared 52–80% identity with others of this variant characterized in fish. When the individual components that encode the tripartite structure were compared, identity was significant across the GnRH, signal and associated peptide encoding regions. Nucleotide similarity between non-coding regions were generally low. In trout, only the cGnRH-II, but not the signal or associated peptide encoding region, shared significant similarity to the cGnRH-II precursor cDNAs characterized from the tree shrew. Cladistic analysis using the bases encoding cGnRH-II precursors resulted in their broad division into two, fish and tree shrew. The fish could be classified generally into two, the Ostariophysi (siluriforms and cypriniforms) and Acanthopterygii (perciforms) together with the Protacanthoptergyii (salmoniforms). Trout shared greatest homology with the Acanthopterygii. Northern analyses identified a single transcript that was expressed in the midbrain only.

Bulk crystallization is emerging as a new industrial operation for protein recovery. Characterization of bulk protein crystallization is more complex than protein crystallization for structural study where single crystals are grown in flow cells. This is because both nucleation and crystal growth processes are taking place while the supersaturation falls. An algorithm is presented to characterize crystallization using the rates of the two kinetic processes, nucleation and growth. The values of these rates allow ready comparison of the crystallization process under different operating conditions. The crystallization, via adjustment to the isoelectric pH of a fungal lipase from clarified fermentation broth, is described for a batch stirred reactor. A maximum nucleation rate of five to six crystals formed per microliter of suspension per second and a high power dependency (approximate to 11) on the degree of supersaturation were found. The suspended protein crystals were found to grow at a rate of up to 15-20 nm/s and also to exhibit a high power dependency (approximate to 6) of growth rate on the degree of supersaturation. (C) 1998 John Wiley & Sons, Inc.

The Welsh Food Microbiological Forum “shopping basket” survey is a long running, structured surveillance program examining ready-to-eat food randomly sampled from the point of sale or service in Wales, United Kingdom. The annual unsatisfactory rates for selected indicators and pathogens for 1998 through 2008 were examined. All the annual unsatisfactory rates for the selected pathogens were

A survey of Listeria in ready-to-eat food took place in Wales, United Kingdom, between February 2008 and January 2009. In total, 5,840 samples were taken and examined for the presence of Listeria species, including L. monocytogenes. Samples were tested using detection and enumeration methods, and the results were compared with current United Kingdom guidelines for the microbiological quality of ready-to-eat foods. The majority of samples were negative for Listeria by both direct plating and enriched culture. Seventeen samples (0.29%) had countable levels of Listeria species (other than L. monocytogenes), and another 11 samples (0.19%) had countable levels of L. monocytogenes. Nine samples (0.15%) were unsatisfactory or potentially hazardous when compared with United Kingdom guideline limits; six (0.10%) were in the unsatisfactory category (100 CFU/g) for Listeria species (other than L. monocytogenes), and three (0.05%) were in the unacceptable or potentially hazardous category (100 CFU/g) for L. monocytogenes. All three of these samples were from sandwiches (two chicken sandwiches and one ham-and-cheese sandwich). The most commonly isolated serotype of L. monocytogenes was 1/2a. This survey was used to determine the current prevalence of Listeria species and L. monocytogenes in ready-to-eat foods sampled from the point of sale in Wales.

The influence of the ortho and para isomers on the crystal morphology of meta-chloronitrobenzene (m-CNB) was observed for both melt-grown crystals and crystals grown from solution using acetone as a solvent. The role of the O-CNB and p-CNB isomers in modifying the m-CNB morphology is the same, irrespective of whether growth takes place from the solution or the melt. The morphological changes are therefore much more influenced by the presence of other isomers than by the acetone solvent.

Hypoxia, or a lack of oxygen, occurs in 50-60% of solid human tumours. Clinical studies have shown that the presence and extent of hypoxia in a tumour cannot be predicted by size or histopathological stage but it is predictive of a poor outcome following radiotherapy, chemotherapy and surgery. However, as a physiological feature of tumours, it can be exploited and researchers have developed many hypoxia-selective chemotherapies or bioreductive drugs that are in varying stages of clinical development. These agents are prodrugs that have two key requirements for their biological activation: they require the reductive environment of a hypoxic tumour cell and the appropriate complement of cellular reductase enzymes. To overcome tumour heterogeneity in reductase enzyme levels and enhance bioreductive drug metabolism a gene therapy strategy can be employed. We have reviewed this field and also present our own pre-clinical research using gene therapy to enhance bioreductive drug treatment for the treatment of cancer. We have specifically focused on studies enhancing lead clinical bioreductive drugs. We consider the metabolic requirements for their activation and we highlight the key in vivo studies supporting the future clinical development of hypoxia-targeted gene-directed enzyme prodrug therapy.

Since 1995, the publicly funded ready-to-eat food sampling and examination activities in Wales have been coordinated and structured, using a novel approach for the identification of samples and premises. The latest set of data from this surveillance system reports the results from 3391 ready-to-eat foods sampled between November 2003 and March 2005. During this seventeen-month period all samples were examined for aerobic colony count, Escherichia coli, Listeria spp., Bacillus cereus, Salmonella, Staphylococcus aureus and Listeria monocytogenes. The food types with the poorest microbiological quality were cream cakes, custard slices and egg mayonnaise sandwiches. The food type with the best microbiological quality was dried fruit. In conclusion, the results indicate that, in general terms, the ready-to-eat food types sampled and examined in this period posed little bacterial hazard to consumers.

Bulk crystallization is emerging as a new industrial operation for protein recovery. Characterization of bulk protein crystallization is more complex than protein crystallization for structural study where single crystals are grown in flow cells. This is because both nucleation and crystal growth processes are taking place while the supersaturation falls. An algorithm is presented to characterize crystallization using the rates of the two kinetic processes, nucleation and growth. The values of these rates allow ready comparison of the crystallization process under different operating conditions. The crystallization, via adjustment to the isoelectric pH of a fungal lipase from clarified fermentation broth, is described for a batch stirred reactor. A maximum nucleation rate of five to six crystals formed per microliter of suspension per second and a high power dependency ( approximately 11) on the degree of supersaturation were found. The suspended protein crystals were found to grow at a rate of up to 15-20 nm/s and also to exhibit a high power dependency ( approximately 6) of growth rate on the degree of supersaturation.

Mass crystallization refers to the production of crystalline materials in bulk; it is widely practised in the chemical and process industries. Examples of products produced in this way range from bulk commodity chemicals such as sodium chloride, fertilizer chemicals and sucrose, through products of the fine and speciality chemicals industry typified by dyestuffs intermediates, agrochemicals and catalysts, to pharmaceuticals and ceramic precursors. Production can take place in continuous or batch units and the range of equipment used is vast, reflecting the different properties and production rates of these products.

Background Malabsorption of fat-soluble vitamins is likely in most patients with cystic fibrosis, particularly those who are pancreatic insufficient. Low vitamin levels are associated with poorer clinical status, and reduced lung function. Since the introduction of improved pancreatic enzymes, normal to high fat diets and routine vitamin supplementation, clinical evidence of fat-soluble vitamin deficiency is rarely seen. Aim To determine the prevalence of fat-soluble vitamin deficiencies in children with cystic fibrosis in Calderdale and Huddersfield NHS Trust. Method Retrospective analysis of vitamin levels performed in children with cystic fibrosis in Calderdale and Huddersfield Trust over a period of six years. Data was available for 19 out of 22 children with cystic fibrosis. Results of plasma vitamin A, D (Total 25 OH Vit D) and E levels for these children were collected on a pre-designed proforma. Results Vitamin A, D and E levels were checked for a total of 75, 75 and 76 times respectively over a period of six years. Vitamin E levels were normal. Vit A levels were subnormal on two occasions. However, Vitamin D levels were sub-optimal ( Conclusion Sub-optimal Vitamin D levels are still very common in children with cystic fibrosis despite routine vitamin supplementation.

Aim The UK is undergoing a major reconfiguration of inpatient paediatric services. Recent guidelines encourage the development of short stay assessment units to increase patient/parent satisfaction and reduce burden on inpatient care. We wish to evaluate a novel 24-hour assessment unit whereby Paediatric Nurse Practitioners (PNPs) take the lead role in assessment and management with additional support provided by doctors. Methods A prospective observational study of acute attendances to this short-stay assessment unit over four data collection periods was performed. Each period lasted one month and each season was included. Outcomes evaluated included: reason for attendance, length of stay, discharges, transfers to the offsite inpatient paediatric ward and re-attendance rates. Results 270 acute attendances (mean age of 5 years, 23% Conclusion The data analysed are comparable to standard doctor-led units reported in the literature and would suggest that this model of care, with appropriate doctor involvement, could be a safe option for a short stay paediatric assessment unit. However to further determine the viability of such a unit, further research is recommended to ascertain cost-effectiveness and parent/staff satisfaction.

We evaluated the effect of a range of physiological concentrations of magnesium on calcium oxalate crystallization from artificial urine in a continuous mixed suspension mixed product removal crystallizer at 37C. Magnesium was found to decrease both the growth and nucleation rates of calcium oxalate crystals in the simulated renal environment.

The pipe flow drag-reducing properties of mixtures of alkyltrimethylammonium halides with 1-naphthol in aqueous solution have been investigated. The effects of solution concentration, soap-naphthol ratio, soap molecular weight and solution temperature upon drag reduction and swirl decay time are reported. The critical wall shear stresses above which the drag-reducing properties cease correlate well with swirl decay time. At low soap concentrations greater than equimolar proportions of 1-naphthol with the soap are required for maximum drag reduction. The drag-reducing properties of these solutions are greatest at and around the Krafft point of the pure soap. A phenomenon similar to onset for polymer solution drag reduction is reported for these soap solutions.

Summary— The effect of glycosaminoglycans on urinary stone formation was evaluated using a mixed suspension, mixed product removal (MSMPR) crystallisation system together with scanning electron microscopy (SEM) to examine the resulting crystals. Chondroitin sulphate was found to decrease the nucleation rate and to promote both the growth rate and suspension density. Results obtained with hyaluronic acid, although inconclusive, are similar to those given by chondroitin sulphate. Heparin sodium salt had a powerful inhibitory effect on both the nucleation rate and the suspension density, the effect increasing in proportion to the heparin concentration. SEM examination showed that the octahedral habit of calcium oxalate dihydrate was modified by the addition of heparin sodium salt and confirmed that the average crystal size in the presence of chondroitin sulphate and hyaluronic acid was significantly greater than the control or that found in the presence of heparin sodium salt.

A technique is described for rapidly assessing the effect of impurities on primary nucleation in solutions. The influence of Ca2+, Sr2+, Ba2+, Ag+, Pb2+, Cr3+ and Ni2+ on the nucleation of potassium sulphate solutions is discussed. It is generally observed that a discontinuity in the behaviour of the impurity occurs at an impurity concentration corresponding to the solubility of the “impurity sulphate” in the solution under investigation. Es wird eine Technik fur die schnelle Abschatzung der Einwirkung von Fremdionen auf die primare Keimbildung in Losungen beschrieben. Der Einflus von Ca2+, Sr2+, Ba2− Ag+ Pb2+ Cr3+ und Ni2+ auf die Keimbildung von Kaliumsulfatlosungen wird besprochen. Es wird generell beobachtet das eine Diskontinuitat im Verhalten der Fremdsubstanz dann auftritt, wenn diese eine Konzentration erreicht, die mit der Loslichkeit des Fremdsulfats in der untersuchten Losung korrespondiert.

Production of secondary nuclei by low energy contacts between a crystal and a solid rod was investigated by direct microscopic observation. Crystal attrition occurred very easily and produced many secondary nuclei. Using both potash alum and magnesium sulphate heptahydrate growing in aqueous solution, large numbers of particles in the size range 1–10 μm were produced in both super- and undersaturated solutions. In addition larger pieces of crystalline material up to 50 μm in size were removed from the crystal under growing conditions. Many of the smaller particles grew very slowly in supersaturated solutions whereas the larger particles appeared to grow at rates characteristic of large crystals.

Experiments, theory and computing methods are described for the analysis of the drying mechanism and the prediction of drier performance. The materials investigated were granular fertilizers of moisture content up to five per cent by weight; their mode of drying was studied in several laboratory devices. The theory analyses these observations and can also be applied to full-scale rotary driers. The experiments described fall into three classes:(i) lines investigation aimed at elucidating the mechanism of moisture transport,(ii) a precision method for studying the gradual drying or wetting of granules, and (iii) a laboratory method for simulating the intermittent process in a rotary drier. The transport mechanism indicated by the results is that of gas-phase diffusion in the pores of the solid material. The driving force is provided by the dependence of the vapour pressure on the moisture content. This function has been determined emperically. The theoretical treatment is based on the numerical integration by finite difference methods, of the partial differential equation for the moisture transport. Because of the emperical driving pressure term, the equation is non-linear, and its solution is possible only by automatic, high-speed methods. Suitable computer programs have been developed and run; stability problems in the integration method have been overcome, and the programs are flexible enough to deal with a variety of boundary conditions. Thus either continuous or intermittent drying can be treated, including the temporary storage of moisture in the interstices of a rolling bed. The agreement between the calculated results and the precision laboratory measurements is completely satisfactory. The postulated mechanism is thus fully compatible with the observations.

Diffusivities of ammonium and potassium alum solutions have been measured by an interferometric technique. Values are recorded for the diffusion of solutions of different concentration into water at 25°, and of solutions containing 2 g. of hydrate/100 g. of water diffusing into water at temperatures within the range 20 to 40°. Measurements have also been made for diffusion between near-saturated solutions, and these values are considered suitable for application in crystal growth and dissolution studies. The activation energy for diffusion in near-saturated solutions (20 to 40°) is approximately 2.8 kcal./mole. Viscosity and density measurements have been made over the temperature range 15–50° and at solution concentrations up to saturation. Solubility data have also been checked over the same temperature range.

The in vitro crystallization of calcium oxalate has been investigated by many workers in the field of renal stone disease with a view to providing some insight into the cause as well as the possible treatment of the disorder1–4. Using different techniques and under a variety of conditions, nucleation, growth and aggregation characteristics of this compound have been examined. In particular, the inhibitory effect of several compounds has received a lot of attention5–10. These studies however have all been limited to static, supersaturated systems and have failed to produce definitive nucleation and growth kinetics. Today the role of inhibitors is recognized as being an important factor in the genesis of renal calculi and recent studies have accordingly been directed towards quantitizing this inhibitory power. In attaining accurate quantitative crystallization kinetics, two important approaches have been utilized. The first employs the use of a continuous crystallizer system and the second involves particle size distribution analysis using a Coulter counter. Finlayson11 was the first to describe the usefulness of a continuous crystallizer as a simple urinary tract model while Robertson and Peacock4 determined the size distribution of calcium oxalate crystalluria in normal and stone forming patients. Miller, Randolph and Drach combined these ideas and have determined the crystallization kinetics of calcium oxalate in simulated urine12 and have also measured the inhibition of calcium oxalate crystallization by pyrophosphate and methylene blue13.

We evaluated the effect of a range of physiological concentrations of magnesium on calcium oxalate crystallization from artificial urine in a continuous mixed suspension mixed product removal crystallizer at 37C. Magnesium was found to decrease both the growth and nucleation rates of calcium oxalate crystals in the simulated renal environment.