More than 75 percent decline over 27 years in total flying insect biomass in protected areas.

Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning.

"Everybody's Different": a primary prevention program among fifth grade school children.

The aim of the present study was to assess the efficacy and effectiveness of the primary prevention program "Everybody's Different" among fifth grade school children. Pre and post measurements were made in both the intervention and control groups regarding body image, weight concern, emotional well-being, attitudes and behaviors associated with disordered eating, self-esteem, anxiety, and depression. The study did not result in any significant improvements regarding self-esteem, eating attitudes, or body image.

Sauer's non-linear voltage division.

The non-linearity of the electrode-tissue interface impedance gives rise to harmonics and thus degrades the accuracy of impedance measurements. Also, electrodes are often driven into the non-linear range of their polarisation impedance. This is particularly true in clinical applications.

Bioelectromagnetics, Carl Durney, and dosimetry: some historical remarks.

The contributions of Carl Durney to dosimetry have decisively advanced the bioelectromagnetics field and led to significant revisions of relevant health standards. Three items come to mind while studying his work: 1. The work of Carl Durney and his colleagues in dosimetry has advanced the bioelectromagnetics field most significantly whereas more abundant work of a biomedical nature has had less impact.

Detection by 4-parameter microscopic imaging and increase of rare mononuclear blood leukocyte types expressing the Fc gamma RIII receptor (CD16) for immunoglobulin G in human sporadic amyotrophic lateral sclerosis (ALS).

By using quantitative multiparameter microscopic imaging we demonstrate concentration of two peripheral mononuclear blood leukocyte types expressing the Fc gamma RIII receptor for immunoglobulin G in a clinical subgroup of amyotrophic lateral sclerosis (ALS, n = 9) showing bulbar palsy (ALSBP) and/or predominant involvement of the upper motor neuron (ALSC). Triple fluorescence staining and overlay with phase contrast images (4 parameters) reveals that cell type 1 co-expresses Fc gamma RIII (CD16), CD8 and CD57 surface antigens (ALSC 50 +/- 33.6 cells/microliters, P = 0.

Modelling of the dielectric properties of normal and irradiated skin.

We have shown that irradiation changes the dielectric properties of human skin at radiofrequencies. Both the dielectric constant and the conductivity of the irradiated skin decrease, especially at low frequencies. The experimental data were analysed using two bioelectric models.

Harmonic distortion caused by electrode polarisation.

Steady-state measurements of the electrical properties of electrodes immersed in physiological saline were taken with small- and large-amplitude sinusoidal voltages (30 m V-1 V) in the frequency range 0.2 mHz-2 Hz. Impedance magnitude and phase, and the first four Fourier series coefficients of the polarised current were measured.

History of medical and biological ultrasound at the University of Pennsylvania.

We briefly review my early contacts with bioacoustics and the bioacoustic work at the University of Pennsylvania that took place from the early 1950s to 1975. It was carried out with E. L.

Mechanisms responsible for electrical properties of tissues and cell suspensions.

The electrical properties of tissues and cell suspensions are most unusual. They change with frequency in three distinct steps and their dielectric constants reach enormous values at low frequencies. We shall concentrate on the 'linear' properties as observed with applied fields less than 1 V/cm.

Cellular membrane potentials induced by alternating fields.

Membrane potentials induced by external alternating fields are usually derived assuming that the membrane is insulating, that the cell has no surface conductance, and that the potentials are everywhere solutions of the Laplace equation. This traditional approach is reexamined taking into account membrane conductance, surface admittance, and space charge effects. We find that whenever the conductivity of the medium outside the cell is low, large corrections are needed.

Electrorotation and levitation of cells and colloidal particles.

We review dielectrophoretic forces on cells and colloidal particles, emphasizing their use for manipulating and characterizing the electrical properties of suspended particles. Compared with dielectric spectroscopy, these methods offer a measure of independence from electrode artifacts and mixture theory. On the assumption that the particles can be modeled as uniform dielectric objects with effective dielectric properties, a simple theory can be developed for the frequency variation in the field-induced forces.

Early history of bioelectromagnetics.

The early history of bioelectromagnetics is reviewed as I experienced it. The period of time chosen extends from my joining the Institute for Physical Foundations of Medicine in Frankfurt in 1937 to the early 1970s, when I retired from the chair of my department at the University of Pennsylvania. Several themes emerge from these recollections.

Linear and nonlinear electrode polarization and biological materials.

Electrode polarization is a major nuisance while determining dielectric properties of cell and particle suspensions and tissues, particularly at low frequencies. Understanding of these interfacial phenomena and appropriate modelling are essential in order to correct for its distortion of the dielectric properties of the sample of interest. I survey the following topics, concentrating on contributions from our laboratory: Linear properties of electrode polarization and relevant models.

Biomedical engineering: University of Pennsylvania-from research laboratory to a leader in educational institutions for bioengineering.

The evolution of the Electromedical Laboratory of the Moore School of Electrical Engineering at the University of Pennsylvania into a biomedical engineering department is summarized. Administrative and educational details for the period when the author served as head and chair (1952-1973) are related.

Organizational development of biomedical engineering.

The evolution of biomedical engineering is traced, beginning with its roots in electrophysiology about 200 years ago. Significant research and professional developments during the 1940s, '50s, and '60s are sketched. Five major events that contributed to these developments are discussed.

Nonlinear phenomenon of interfacial polarization immittance of a Pt electrode.

Description of a computerized, automated method to measure the interfacial polarization immittance of a Pt electrode in nonlinear range is presented. The classical three-electrode setup is used for measurements in conjunction with a special purpose software implemented on a Unix computer using C language. A collection of data at very low frequencies (below 2 Hz) and at high input intensities with various dc biases imposed on the input are presented to show the behavior of the interface in nonlinear range.

Dielectric properties of tissues and biological materials: a critical review.

We critically review bulk electrical properties of tissues and other biological materials, from DC to 20 GHz, with emphasis on the underlying mechanisms responsible for the properties. We summarize the classical principles behind dielectric relaxation and critically review recent developments in this field. Special topics include a summary of the significant recent advances in theories of counterion polarization effects, dielectric properties of cancer vs.

Biological effects of non-ionizing radiations: cellular properties and interactions.

The Lauriston Taylor lectures honor the founder of the National Committee on Radiation Protection and Measurement, soon to be followed by the corresponding international organization. These standard setting bodies had a vast influence on proper recognition of radiation hazards. The 10th Taylor lecture is the first to deal with nonionizing radiations and may be, therefore, of particular interest to the bioengineer.

Alignment of microscopic particles in electric fields and its biological implications.

It is well known that electromagnetic fields cause mechanical forces. If one applies an electrical field to a suspension of microscopic particles, these particles realign themselves along the direction of the field and form pearl-chain-like aggregates. These chains are mostly single stranded but they are frequently multistranded.

Science and standards. RF-hazards and standards: an historical perspective.

The following topics are discussed: Standard of safety considerations. Early efforts in bioengineering and biophysics before and after World War II, Work after World War II (1950s), Early interest in hazards, Soviet work and The Tri-Service area and ANSI. The author concludes that the historical development of biophysics and bioengineering, both as a whole and in the specialty area of nonionizing radiation, proceeded in a fairly rational fashion.