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To describe the mental models people hold about the COVID-19 pandemic, with a focus on how they understand the factors that drive the spread of COVID-19 and what kind of beliefs are associated with these models.In a series of three studies (total N = 461), we asked participants to identify factors that are relevant for COVID-19 proliferation (Study 1a), rate the importance of factors (Study 1 b), and create a mental model of how these factors relate to virus spread by employing a validated tool for mental model elicitation (Study 2). Main outcome measures: inclusion and centrality of factors in mental models of COVID-19 infection spread.Mitigation measures issued by government, adherence to measures, and virus characteristics were most strongly represented in participants' mental models. Participants who perceived measures as appropriate or who experienced more control and more worry over the spread of the virus created more complex models compared to participants who were less satisfied with measures or who felt lower control and less worry.These findings suggest that people are able to create sensible mental models of virus transmission but may appreciate transparent communication to comprehend the bigger picture behind the governmental mitigation strategy.

Memristors or memristive devices are two-terminal nanoionic systems whose resistance switching effects are induced by ion transport and redox reactions in confined spaces down to nanometer or even atomic scales. Understanding such localized and inhomogeneous electrochemical processes is a challenging but crucial task for continued applications of memristors in nonvolatile memory, reconfigurable logic, and brain inspired computing. Here we give a survey for two of the most powerful technologies that are capable of probing the resistance switching mechanisms at the nanoscale – transmission electron microscopy, especially in situ, and scanning tunneling microscopy, for memristive systems based on both electrochemical metallization and valence changes. These studies yield rich information about the size, morphology, composition, chemical state and growth/dissolution dynamics of conducting filaments and even individual metal nanoclusters, and have greatly facilitated the understanding of the underlying mechanisms of memristive switching. Further characterization of cyclic operations leads to additional insights into the degradation in performance, which is important for continued device optimization towards practical applications.

This work studies plastic behaviour and its influence on the abrasive wear resistance of a group of high chromium white cast irons. The irons were poured in metallic moulds and heat treated. The studied alloys have 3% C, 12% Cr, as well as 0.6% and 2.4% Si. The plastic characteristics are evaluated through the parameters obtained from Meyer's test: the strain hardening capacity (n) and the constant of penetration resistance (k). The influence of silicon content and applied heat treatments on Meyer's test parameters was determined. The heat treated samples showed values between n=2.3 and n=2.5. These values confirm a hardening capacity greater than the cast specimens. The high silicon alloy specimens show greater n-values than the low silicon alloy ones. This tendency is remarked when the complete treatments (austenitizing, cooling and holding) are applied. Correlation between n, k and the relative abrasive wear show good values for (k), but too much dispersion for the Meyer's Index (n).

Primary aldosteronism encompasses 2 major underlying causes: (1) aldosterone producing adenoma and (2) bilateral adrenal hyperplasia. In addition to the aldosterone excess, increased production of other compounds of the steroidogenic pathways may be involved. Until recently, most studies examined the production of steroids other than aldosterone in tumor tissue, urine, or peripheral plasma samples, but several new studies have also addressed steroid levels in adrenal venous blood samples using liquid chromatography tandem mass spectrometry. Plasma and tissue levels of several precursors of aldosterone with mineralocorticoid activity are higher in patients with aldosterone producing adenomas than in those with bilateral hyperplasia. These include corticosterone, deoxycorticosterone, and their 18-hydroxylated metabolites. Similarly, urinary, peripheral, and adrenal venous concentrations of the hybrid steroids 18-oxocortisol and 18-hydroxycortisol are higher in patients with aldosterone producing adenomas than in bilateral hyperplasia. Differences in the pathophysiology and in clinical and biochemical phenotypes caused by aldosterone producing adenomas and bilateral adrenal hyperplasia may be related to the differential expression of steroidogenic enzymes, and associated to specific underlying somatic mutations. Correct appreciation of differences in steroid profiling between aldosterone producing adenomas and bilateral adrenal hyperplasia may not only contribute to a better understanding of the pathogenesis of primary aldosteronism but may also be helpful for future subtyping of primary aldosteronism.

Alternative splicing of pre-mRNA increases proteomic diversity, a crucial mechanism in defining tissue identity. We demonstrate differentially spliced interleukin (IL)-7 in distinct anatomic areas in the adult, in developing human brains and in normal human neuronal progenitor (NHNP) cells. IL-7c (c, the canonical form spanning all six exons) or its variants IL-7 delta 5, delta 4 or delta 4/5 were cloned and expressed as recombinant proteins. IL-7 and splice variants were able to shift the differentiation of NHNP cells as compared with the diluent control (P0.01) defined by anti-beta (III)-tubulin and glial fibrillary acidic protein expression, with different degrees (IL-7cdelta 4/5IL-7 delta 5); IL-7 delta 4 exhibited a significantly weaker potency. Differentiation was confirmed by transcriptome analysis of IL-7c-stimulated neural NHNP cells, resulting in 58 differentially expressed genes; some of these are involved in neural differentiation, for example, the developmentally regulated transcription factor krüppel-like factor 12, musashi 2, a translational regulator of cell fate or the sonic hedgehog receptor patch 1. This suggests that IL-7 influences neural development at a molecular level by participating in human brain architecture through glia cell formation: a paradigm that alternative splicing in cytokines, for example, for IL-7, has a physiological role in human organ development and progenitor cell differentiation.

Three different coating conditions influencing the quality of a silicon polyester galvanized steel system were investigated by means of EIS. The first aim was to investigate the influence of different types of pores or discontinuities on the corrosion resistance of the above-mentioned coating system. A second aim was to study the influence of mechanical deformation and damage of the coating on the corrosion behaviour of the coating system. Finally, degradation due to ultraviolet exposure was investigated. In each of these investigations it was possible to distinguish different time constants for different electrochemical events in the Bode phase diagram. Since the difference in magnitude of the values of the resistances was large, they could not be distinguished in the Nyquist plots. Therefore, this type of plot was not used in this work. From the build-up of the coating system and the number of time constants deduced from the EIS measurements, it was possible to model the system. From the model, the physical and electrochemical phenomena occurring during the service life of an imperfect organic coating system was explained.

In this paper the influence of a mechanical deformation on the corrosion behaviour of a silicon polyester coated galvanised steel is investigated. The electrochemical behaviour of samples subjected to several degrees of uniaxial elongation (1–10% of total strain) is compared with the one of the samples bent over different mandrel diameters. First, the coating aspect of the different types of samples was investigated, by optical microscopy and with scanning electron microscopy (SEM). Strain effects causes damage up to the formation of cracks in the coating. Further, a relationship between the strain introduced by uniaxial deformation and the strain caused by bending of the sample could be formulated. Finally, the influence on the corrosion resistance after uniaxial deformation is compared with that caused by bending deformation. To conclude, it was possible to confirm the theoretically formulated relationship between uniaxial and bending deformation by means of microscopy and by electrochemical techniques.

Silicon polyester coated steel plate is frequently used because of its good corrosion resistance under various conditions. However, if the application of the coating and/or the curing process is carried out too fast, evaporating solvent is enclosed in the coating, forming pores. The aim of this study is to investigate the influence of different types of pores on the corrosion resistance of the above-mentioned coating system by means of electrochemical impedance spectroscopy (EIS). Three different phases in the degradation process could be observed. An almost intact coating area is investigated as reference coating. By simultaneous interpretation of the measured corrosion potential, the evolution of the coating capacitance and its resistance, it can be concluded that this system provides a very good corrosion resistance in a saline environment. A coating containing only small macro-pores (2 μm 100 μm) can even reach the underlying zinc surface. They will strongly decrease the corrosion protection behaviour of the coating.

Independent medical specialists in the Netherlands are treated as entrepreneurs for tax purposes and therefore enjoy tax benefits. A change in the legal relationship between medical specialists and hospitals is foreseen in 2015. Independent medical specialists will then no longer be considered to be entrepreneurs. This could negatively affect their tax position. The Dutch government has adopted a policy aimed at controlling expenses arising from medical specialists' fees. According to this policy, the formation of regional practices or mega-practices of specialists will be discouraged. In contrast, the current fiscal legislation encourages medical specialists to incorporate their practice into regional practices or mega-practices or to become shareholders of their hospitals. It has been proposed that fiscal benefits be linked to certain aspects of entrepreneurship, such as investing in medical equipment or employing medical personnel.

In this paper a new method is proposed for the calculation of the impedance of arbitrary electrodes containing noncylindrical pores and/or having place-dependent impedances. The method is based on splitting up the pore and the surrounding material into N discs. For the equivalent circuit of each disc a transmission line with constant impedances is adopted. By matrix calculations the impedance of the porous electrode can be obtained. A comparison is made between this, very general, matrix method and a recursion method developed by Keiser et al. for purely capacitive interface behaviour of pores in an electrode material with negligible impedance. It is shown that the matrix method requires much smaller N-values owing to the use of transmission lines for each disc. This makes it more appropriate to be used in curve fitting procedures. Moreover, it is shown that the typical behaviour of the pore impedance at low penetration depths is much better simulated with the matrix method. Furthermore, an attempt is made to provide more general knowledge about the impedance behaviour of noncylindrical pores as a function of the penetration depth of the a.c. signal. Finally, the theory is enlarged using constant phase elements instead of capacities to describe the behaviour of the electrode/electrolyte interfaces.

The method of one-dimensional modelling of the pore impedance is validated on pores drilled in AISI 316 stainless steel. Impedance measurements were carried out in 0.511 sulphuric acid solution. Experimentally, it is found that, for cylindrical pores with a radius/pore length-ratio smaller than 0.5, the one-dimensionality condition is satisfied. Furthermore, impedance measurements on noncylindrical, scaled-up pores provide evidence that a geometric constant Ag has to be introduced, as in Part I. In accordance with this theory it is found that for pores with narrowing cross section Ag is less than 1/3, while for pores with a broadening cross section Ag is greater than 1/3. Moreover, it is shown that the matrix method, presented in Part I, provides a way of calculating the impedance of a non-cylindrical pore by using a highly reduced number of discs, N, compared to the recursion method of Keiser et al. This is an advantage in fitting procedures.

For anodizing of aluminium in a sulphuric acid (15 mass%) solution at constant voltage, the current initially jumps to a high value and decreases rapidly to a low value in the first few seconds; thereafter the current rises to a constant level. The course of the current versus time is common for all applied voltages and temperatures. However, the higher the voltage and temperature are, the faster and higher the rise and constant level will be. The shape of this current-time curve is representative for the specific anodization layer. Exponential relations has been found for the different characteristic points (minimum, maximum and steady-state current and the corresponding times) of the current density-time curve versus voltage and temperature. Also for the thickness and the apparent specific mass of the oxide layer, exponential functions versus voltage and temperature were found. In this work it has been proved that a correlation exists between the measured steady-state current density, the thickness and the apparent specific mass of the layer. For the formed oxide layers the measured mean real specific mass value is the same as that one which has already been published.

In connection with the development of a general strategy for solid-phase extraction (SPE) of drugs, the use of the apolar octadecyl silica bonded phase and ion-exchanging phases with a benzene sulphonic acid or quaternary amine bonded functionality is investigated for the SPE of small polar drugs. This investigation was performed on a set of 15 drugs, belonging to varying pharmacological groups and with varying structures. For each analyte, its adsorption on the C18 and the ion-exchanging phase was controlled for an aqueous solution and for a spiked plasma sample. For those analytes retained on the sorbent, different elution solvents were compared. Although SPE methods could successfully be developed for some drugs, no general solution can be proposed and no solution was found for a few drugs. The main problems are that for these few drugs no sufficient retention is obtained on any SPE phase investigated or the selectivity is too low.

OBJECTIVE Recently, the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research Trial demonstrated that treatment with the angiotensin receptor blocker (ARB) valsartan for 5 years resulted in a relative reduction of 14% in the incidence of type 2 diabetes in subjects with impaired glucose metabolism (IGM). We investigated whether improvements in β-cell function and/or insulin sensitivity underlie these preventive effects of the ARB valsartan in the onset of type 2 diabetes. RESEARCH DESIGN AND METHODS In this randomized controlled, double-blind, two-center study, the effects of 26 weeks of valsartan (320 mg daily; n = 40) or placebo (n = 39) on β-cell function and insulin sensitivity were assessed in subjects with impaired fasting glucose and/or impaired glucose tolerance, using a combined hyperinsulinemic-euglycemic and hyperglycemic clamp with subsequent arginine stimulation and a 2-h 75-g oral glucose tolerance test (OGTT). Treatment effects were analyzed using ANCOVA, adjusting for center, glucometabolic status, and sex. RESULTS Valsartan increased first-phase (P = 0.028) and second-phase (P = 0.002) glucose-stimulated insulin secretion compared with placebo, whereas the enhanced arginine-stimulated insulin secretion was comparable between groups (P = 0.25). In addition, valsartan increased the OGTT-derived insulinogenic index (representing first-phase insulin secretion after an oral glucose load; P = 0.027). Clamp-derived insulin sensitivity was significantly increased with valsartan compared with placebo (P = 0.049). Valsartan treatment significantly decreased systolic and diastolic blood pressure compared with placebo (P < 0.001). BMI remained unchanged in both treatment groups (P = 0.89). CONCLUSIONS Twenty-six weeks of valsartan treatment increased glucose-stimulated insulin release and insulin sensitivity in normotensive subjects with IGM. These findings may partly explain the beneficial effects of valsartan in the reduced incidence of type 2 diabetes.

The pore-filling method is a known process for measuring the porosity of porous anodic oxide layers on aluminium. This method has been used to study the relationship between the anodizing conditions and the porosity of the porous anodic film. In a series of experiments, the influence of the anodization voltage and temperature on the porosity, of an anodization layer formed in 15 wt.% sulphuric acid was investigated. From these results a mathematical equation was deduced that gives the porosity as a function of the anodization voltage and temperature. In the second part of the study the height of the voltage jump, on which the thickness of the barrier layer at the start of the re-anodization process depends, was investigated as a function of the anodization voltage. A linear relationship was found between the voltage jump and the anodization voltage.

In connection with the acquisition of knowledge for an expert system for solid-phase extraction (SPE), a preliminary investigation was made of the kinds of sorbents that can be used for the SPE of small acid analytes. The development of a simultaneous solid-phase extraction of the preservatives benzoic acid and sorbic acid and the artificial sweeteners saccharin and aspartame is presented. Both preservatives and saccharin are retained on a silica-based quaternary ammonium anion exchanger. Elution is effected with a mixture of methanol and 1% sulphuric acid. Aspartame is not retained on the anion exchanger, but the collected adsorption and was solvents containing the aspartame can be extracted on the octadecyl sorbent. The extracts are chromatographed in the reversed-phase mode on a C18 column with a mobile phase consisting of phosphate buffer (pH 4.5, ionic strentht 0.1) and acetonitrile. Recoveries of at least 95% were observed and the relative standard deviation was < 3.2%. Comparison of an external callibration line for aqueous standard solutions, a calibration line for extracted aqueous samples and a standard addition line for soft drinks showed that the developed method is unbiased when applied to concentrations of up to 20 mg l−1 in soft drinks.

In order to study user-producer interaction (UPI) in emerging pharmaceutical and food innovation processes, a classification of user involvement has been developed, including a contextualised view on UPIs. Case studies are performed on two types of UPI: demand articulation in intermediary organisations and interactive learning in consortia, in the pharmaceutical and food sector, respectively. Regarding demand articulation processes, articulation of problems, needs, demands and expectations through agenda-setting practices is important. Expression and evaluation of demands with other factors leads to moblization of creative potential of prospective users and facilitation of emerging innovation processes. Regarding interactive learning, geographical, organisational, regulatory and cognitive proximity conditions could facilitate structures for emerging technology development, and codes and networks for frequent interaction between complementary stakeholders. Demands, concerns and opportunities are articulated by shared visions. Organised UPIs via intermediary user organisations or consortia seem to be the important tools for demand articulation and interactive learning involving patient organisations, researchers and private and public organisations. © 2008 Imperial College Press.

Pharmacogenomics is a quickly evolving field of research that increasingly impacts individuals and society. As some innovations in biotechnology have experienced strong public opposition during the 1990s, interaction between producers and users of these innovations may help in increasing their success in social and economic terms. However, conditions for effective interaction have so far remained under-explored. This paper explores user-producer interactions in pharmacogenomics from an innovation and science communication perspective in the Netherlands. To find possible ways of engaging stakeholders in an early stage of technology development, ie, when science policy is in the making, we present communication activities derived from the field of policy analysis. To articulate motives for two-way public participation in genomics innovation processes, we describe two levels at which pharmacogenomics developments will have an input:1) at the meso-level of medical practice with already established medical technologies, values and routines, suppliers and health professionals (general practitioners, pharmacists), and 2) at the macro-level of society at large, with established institutions, infrastructures, and broadly shared values and beliefs among citizens in general. Thereby we offer a starting point for optimising decision-making processes in the field of pharmacogenomics innovations, including important aims to be reached, stakeholders to be involved, and some criteria for designing interactive communication activities.

Since 2003, the professional social work has been acknowledged as a professional occupation. In compliance with the Social Service and Social Assistance Law (further – Law), local municipalities are responsible for carrying out individual work with families and children, where there are negative preconditions for the development of a child. The city of Riga is the capital of Latvia and the largest municipality with the broadest spectrum of experience in providing social assistance and social services. Riga can boast with the two-levelled organisation of social work: direct social work with a client is carried out at Riga Social Office; however, social assistance and its programme administration is the responsibility of Welfare Department of Riga. Data show that especially during the period of economic crisis and after-crisis period the number of clients of social workers – families – has markedly increased. If back in 2008, up to 3063 families needed social assistance and social services; in 2011, the number of families in need of such assistance had already reached 3216. This indicates the steady growth of social work in Riga. In 2011, social services and social assistance to 3216 families was provided with the help of 66 social workers. The total number of people served reached 11,947 persons; the number included 7.565 adults and 4.868 children.1 These families frequently suffer from depression, alcoholism, drug addiction; they are exposed to potential risks of poverty and family violence, as well as may develop criminal cases. Those families where any of the above mentioned risks are present suffer from dysfunctional familial relationships. One of the services provided to such families is individual case work. The service helps families with children to define, solve or lessen social problems by developing the resources of the involved individuals and by employing various systems of assistance. The number of social service workers in Riga Social Office is rather unchangeable; however, clients with problems of multiple and complicated nature increase. Evaluation is a crucial part of every professional activity. It is not a rare case that in Latvia the evaluation of the provided service means formally defining what has been done, for example, the number of consultations provided during face to face meetings and over the phone, the number of visitations, the number of the produced informative letters, the number of the services provided or the number of cases per social worker a year. The aim of the study is to evaluate the quality of the case work system in providing social assistance. The research involved the unity of all the activities undertaken by a social worker when focusing on case work. Quality assessment criteria were defined for the sake of carrying out the research.

We studied the pulsed laser deposition of homoepitaxial SrTiO3 thin films in different deposition regimes in order to elucidate the possibility to promote two-dimensional growth by increasing the kinetic energy of the oncoming particles. The kinetic energy of the oncoming species is determined by exploiting plume diagnostics techniques and the resulting nucleation and growth processes are analysed by reflection high-energy electron diffraction and atomic force microscopy. We could show that although the kinetic energy of the oncoming species varies to a great extent, the diffusion process is mostly influenced by the stoichiometry. Under stoichiometric conditions, obtained only in a limited window of process parameters, the adatoms on the surface have the highest diffusivity, thus promoting a step-flow growth mode. Under nonstoichiometric conditions, both Sr- and Ti-rich, the diffusivity is strongly reduced. This results in a transition from a two-dimensional to a three-dimensional growth under Sr-rich conditions. Conversely, in the Ti-rich case, obtained at high laser fluence, the two-dimensional growth sustains until the end of the growth process. We attribute this to the high island density available at high laser fluence which facilitates the diffusion of adatoms to step edges despite of their reduced diffusion length.

A major H2-Kd-presented epitope for antilisterial cytotoxic T lymphocytes (CTLs) is the nanomer peptide which corresponds to the amino acid 91 to 99 (aa91-99) sequence from listeriolysin O (LLO). Although the LLO sequence contains at least five additional nanomer peptides which also satisfy the H2-Kd binding motif, aa91-99 is the only LLO-derived target peptide that is recognized by antilisterial CTLs following infection of BALB/c mice with Listeria monocytogenes. In order to investigate further the immunodominance of the LLO aa91-99 epitope following endogenous processing of LLO, we introduced a point mutation in hly (the gene for LLO) which results in a conservative Y-to-F substitution for the anchor residue at position 2 within the aa91-99 sequence. This "92F" L. monocytogenes mutant produces biologically active LLO and is phenotypically indistinct from wild-type L. monocytogenes in terms of intracellular growth in vitro and virulence in vivo. BALB/c mice actively immunized with the 92F L. monocytogenes mutant are protected against challenge with wild-type L. monocytogenes. Antilisterial CTLs from mice immunized with the 92F mutant lyse targets infected with L. monocytogenes; however, these CTLs do not lyse target cells pulsed with either the LLO aa91-99 peptide, other LLO-derived peptides which satisfy the H2-Kd binding motif, or a peptide corresponding to the LLO aa91-92F-99 sequence. Target cells pulsed with the LLO aa91-92F-99 peptide are, however, lysed by wild-type LLO aa91-99-specific cytotoxic cells. Thus, a conservative amino acid change in the first anchor residue of the immunodominant aa91-99 sequence of LLO eliminates the induction of the cytotoxic cell response to this epitope as well as to any of the other candidate LLO-derived peptides which fit the H2-Kd binding motif. The lack of anti-LLO-specific CTLs following immunization with the 92F mutant does not appear, however, to influence the protective antilisterial immune response.

Municipal social policy has an important role in dealing with social problems of citizens. On micro level, municipalities spend a substantial amount of their budget solving such problems. However, increasing the amount of money spent on solving problems of each individual at micro level does not provide efficient fulfilment of the tasks defined for municipal social policy making. Thus new, complementary solutions should be looked into, as new ways of development of social work in municipalities should be designed with the aim to increase the level of citizen participation and joint responsibility, especially of socially vulnerable groups. Research results let the author conclude that social activity of socially vulnerable groups should be promoted by creating a series of prerequisites, among which citizen participation, need for organisational support, activities that would foster politician and municipality officials’ attitude towards citizen participation and their social capital increase, two-way relationship between citizens and officials, and the worker that would promote citizen participation, among which is social policy making, are considered to be very important. All of this can be successfully reached by developing community work in local municipalities. This is the missing link to combine macro and micro levels, or political determination and practical implementation of citizen participation.

Techniques for the preparation of biological samples are often based nowadays on solid-phase extraction (SPE). The different SPE steps can be performed automatically on disposable extraction cartridges (DECs) by means of a sample processor. A knowledge-based system was developed to facilitate the development of fully automated methods for the solid-phase extraction of relatively hydrophobic basic drugs from plasma, coupled with their determination by high-performance liquid chromatography (HPLC). The DEC filled with 50 mg of cyanopropyl-bonded silica phase is first conditioned with methanol and buffer solution (pH 7.4). After sample application, the DEC sorbent is washed with the same buffer. The analytes are then desorbed with an appropriate eluent and the eluate is finally diluted with the same buffer as used in the HPLC mobile phase before injection. Under these conditions, only three variables are still to be optimized: the composition and volume of the elution solvent and the volume of buffer to be added to the eluate. On the basis of this general strategy, a decision tree providing information about suggested starting conditions and guidelines for the optimization of the three variables was developed and implemented by use of a hypermedia software. This didactic expert system was evaluated using several beta-receptor blocking agents as model compounds and the operating conditions obtained for the automated SPE of these compounds are presented. A method for the determination of propranolol in plasma using the SPE conditions deduced from the knowledge-based system was validated. The absolute recovery of propranolol is ca. 93% and the limit of detection is 1.3 ng ml-1. The mean within-day and between-day reproducibilities are 2.3 and 3.6%, respectively.

Fifteen different isolates of Pseudomonas aeruginosa were used to study the kinetics of adhesion to 304 and 316-L stainless steel. Stainless steel plates were incubated with approximately 1.5 X 10(7) CFU/ml in 0.01 M phosphate-buffered saline (pH 7.4). After the plates were rinsed with the buffer, the number of adhering bacteria was determined by a bioluminescence assay. Measurable adhesion, even to the electropolished surfaces, occurred within 30 s. Bacterial cell surface hydrophobicity, as determined by the bacterial adherence to hydrocarbons test and the contact angle measurement test, was the major parameter influencing the adhesion rate constant for the first 30 min of adhesion. A parabolic relationship between the CAM values and the logarithm of the adhesion rate constants (In k) was established. No correlation between either the salt aggregation or the improved salt aggregation values and the bacterial adhesion rate constants could be found. Since there was no significant correlation between the bacterial electrophoretic mobilities and the In k values, the bacterial cell surface charge seemed of minor importance in the process of adhesion of P. aeruginosa to 304 and 316-L stainless steel.

Recently a graphical method for the determination of the charge transfer resistance, obtained from impedance measurements, was developed. The original method was limited to perfect, semicircular Nyquist plots. Extension to inclined or depressed semicircular arcs is made possible by a few simple mathematical and graphical manipulations.

Summary Electrochemical impedance measurements on conventional dental amalgams at an anodic polarization potential of −250 mV vs. SCE were performed. An initial evaluation was given in part I of this study; in the second part the results are interpreted in terms of a model. The latter, characterized by an equivalent circuit, is a parallel combination of a flat surface and a pore. The selection of appropriate values for the elements of the equivalent circuit leads to a better insight into the corrosion process. Although no simple relationship exists between the circuit elements and the impedance curves, an explanation was found for some typical features of these curves. As an application, the influence of the anodic polarization potential on the impedance curves was studied. Evaluation by means of the model demonstrated the importance of the characteristics of the corrosion products.