Non-linear dielectric spectroscopy: antifouling and stabilisation of electrodes by a polymer coating.

Non-linear dielectric spectroscopy (NLDS) has previously been shown to produce quantitative information that is indicative of the metabolic state of various organisms, by modeling the non-linear effects of their membranous enzymes on an applied oscillating electromagnetic field using supervised multivariate analysis methods. However, the instability of the characteristics of the measuring apparatus rendered the process temperamental at best in the laboratory and impractical for field use. The main practical problem, of the non-stationarity of the electrode-solution interface and the ease with which the electrode surfaces are subject to protein fouling.

Metals and metalloids in tissues of American alligators in three Florida lakes.

Concentrations of metals and selenium were examined in tissues of American alligators (Alligator mississippiensis) from three lakes in central Florida, in one of which alligators have exhibited reproductive or developmental defects. Our overall objective was to determine whether the levels of metals were sufficiently high to confound the association between chlorinated hydrocarbons, which are elevated in eggs and juvenile plasma, and reproductive impairment. The concentrations of all metals were relatively low compared to those reported for alligators from elsewhere in Florida and the southeastern United States, suggesting that reproductive impairment is not due to metals and that metals pose no health risk to the alligators.

Anonymous linkage of New Zealand mortality and Census data.

Background: The New Zealand Census-Mortality Study (NZCMS) aims to investigate socio-economic mortality gradients in New Zealand, by anonymously linking Census and mortality records.

Objectives: To describe the record linkage method, and to estimate the magnitude of bias in that linkage by demographic and socio-economic factors.

Methods: Anonymous 1991 Census records, and mortality records for decedents aged 0-74 years on Census night and dying in the three-year period 1991-94, were probabilistically linked using Automatch.

Daily mortality in relation to weather and air pollution in Christchurch, New Zealand.

Objective: To investigate the relationship between the daily number of deaths, weather and ambient air pollution.

Method: An ecological study. We assembled daily data for the city of Christchurch, New Zealand (population 300,000) from June 1988 to December 1993.

Measures of exposure to environmental tobacco smoke. Validity, precision, and relevance.

It is often not clear what the best measures of exposure are for a risk assessment, or even how one should answer this question. Environmental tobacco smoke (ETS) provides a good example for an exploration of uncertainty. There are a variety of methods for estimating exposure and each has short-comings.

Balanitis xerotica obliterans with urethral stricture after hypospadias repair.

Three cases of urethral stricture due to balanitis xerotica obliterans (BXO) after hypospadias repair are reported. The first patient showed white, dense scarring on the prepuce before the hypospadias repair and developed a stricture of the urethra after the operation. The second and the third were uneventful for 6 and 2 years, respectively, after the hypospadias repair, and then developed urethral strictures.

National infant mortality rates in relation to gross national product and distribution of income.

We examined the relation between infant mortality rates, gross national product, and income distribution. Our findings support the hypothesis that average measures of population health are influenced by the distribution of income within societies.

The use of nonlinear dielectric spectroscopy to monitor the bioelectromagnetic effects of a weak pulsed magnetic field in real time.

Nonlinear dielectric spectroscopy (NLDS) was used to detect interaction of a pulsed magnetic field (PMF) with membrane protein dynamics in aggregating Dictyostelium discoideum amoebae. In the experiments reported here, a strong nonlinear dielectric response of Dictyostelium discoideum cells is shown, and a distinctive nonlinear dielectric response of cells previously exposed to PMF is shown. The method of NLDS is shown to be capable of monitoring and charting the dynamic frequency response of the cell to an electromagnetic field.

Something in the water? A health impact assessment of disinfection by-products in New Zealand.

Disinfection by-products (DBP) are a large group of halogenated chemicals formed by the reaction of disinfectant agents with naturally-occurring organic substances in water. Numerous studies have found associations between DBP and some cancers and adverse reproductive outcomes. For both cancer and birth defects the relative risk associated with exposure to DBP is about 1.

Plasma steroid concentrations and male phallus size in juvenile alligators from seven Florida lakes.

Neonatal and juvenile alligators from contaminated Lake Apopka in central Florida exhibit abnormal plasma sex steroid concentrations as well as morphological abnormalities of the gonad and phallus. This study addresses whether similar abnormalities occur in juvenile alligators inhabiting six other lakes in Florida. For analysis, animals were partitioned into two subsets, animals 40-79 cm total length (1-3 years old) and juveniles 80-130 cm total length (3-7 years old).

Rapid analysis of high-dimensional bioprocesses using multivariate spectroscopies and advanced chemometrics.

There are an increasing number of instrumental methods for obtaining data from biochemical processes, many of which now provide information on many (indeed many hundreds) of variables simultaneously. The wealth of data that these methods provide, however, is useless without the means to extract the required information. As instruments advance, and the quantity of data produced increases, the fields of bioinformatics and chemometrics have consequently grown greatly in importance.

El Niño and arboviral disease prediction.

Recent El Niño events have stimulated interest in the development of modeling techniques to forecast extremes of climate and related health events. Previous studies have documented associations between specific climate variables (particularly temperature and rainfall) and outbreaks of arboviral disease. In some countries, such diseases are sensitive to El Niño.

Genetic programming as an analytical tool for non-linear dielectric spectroscopy.

By modelling the non-linear effects of membranous enzymes on an applied oscillating electromagnetic field using supervised multivariate analysis methods, Non-Linear Dielectric Spectroscopy (NLDS) has previously been shown to produce quantitative information that is indicative of the metabolic state of various organisms. The use of Genetic Programming (GP) for the multivariate analysis of NLDS data recorded from yeast fermentations is discussed, and GPs are compared with previous results using Partial Least Squares (PLS) and Artificial Neural Nets (NN). GP considerably outperforms these methods, both in terms of the precision of the predictions and their interpretability.

Laparoscopic retroperitoneal repair of recurrent postoperative lumbar hernia.

A patient who previously underwent an attempt at open mesh repair of a lumbar hernia that occurred following iliac crest bone harvesting was managed successfully by laparoscopic retroperitoneal fixation of the prosthetic material to the iliac crest using bone screws. A review of the literature supports the use of such a novel approach to manage this often vexing problem.

A weak pulsed magnetic field affects adenine nucleotide oscillations, and related parameters in aggregating Dictyostelium discoideum amoebae.

A model eukaryotic cell system was used to explore the effect of a weak pulsed magnetic field (PMF) on time-varying physiological parameters. Dictyostelium discoideum cells (V12 strain) were exposed to a pulsed magnetic field (PMF) of flux density 0.4 mT, generated via air-cored coils in trains of 2 ms pulses gated at 20 ms.

Serum concentrations of various environmental contaminants and their relationship to sex steroid concentrations and phallus size in juvenile American alligators.

Recent studies have reported a number of abnormalities in the hatchling and juvenile alligators of Lake Apopka, FL (USA). These abnormalities include modifications of plasma concentrations of sex steroids in males and females as well as abnormalities in gonadal morphology, gonadal enzyme activity, and steroidogenesis. Embryonic exposure to environmental contaminants in the eggs has been hypothesized to be the causal agent for these changes.

Infants' learning about words and sounds in relation to objects.

In acquiring language, babies learn not only that people can communicate about objects and events, but also that they typically use a particular kind of act as the communicative signal. The current studies asked whether 1-year-olds' learning of names during joint attention is guided by the expectation that names will be in the form of spoken words. In the first study, 13-month-olds were introduced to either a novel word or a novel sound-producing action (using a small noisemaker).

Smoking hygiene: a study of attitudes to passive smoking.

Aim: To study the attitudes and knowledge of adults in the Wellington area about the effects of passive smoking and measures to reduce exposure to smoke.

Methods: A sample of 200 people, randomly selected in the Wellington area, answered a telephone survey on passive smoking.

Results: Of the 200 respondents, 160 (80%) were males, 40 (20%) were females and approximately one-third (30%) were smokers.

Tumoricidal activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo.

To evaluate the utility of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a cancer therapeutic, we created leucine zipper (LZ) forms of human (hu) and murine (mu) TRAIL to promote and stabilize the formation of trimers. Both were biologically active, inducing apoptosis of both human and murine target cells in vitro with similar specific activities. In contrast to the fulminant hepatotoxicity of LZ-huCD95L in vivo, administration of either LZ-huTRAIL or LZ-muTRAIL did not seem toxic to normal tissues of mice.

El Niño and the dynamics of vectorborne disease transmission.

The objective of the study was to investigate the relationship between reported incidence of dengue fever and El Niño southern oscillation (ENSO) in 14 island nations of the South Pacific. Using a mixed ecological study design, we calculated correlations between annual averages of the southern oscillation index (SOI), local temperature and rainfall, and dengue fever. We also calculated temporal correlations between monthly reports of dengue fever cases on different islands.