Capillary-driven horseshoe vortex forming around a micro-pillar.

Hypothesis: Horseshoe vortices are known to emerge around large-scale obstacles, such as bridge pillars, due to an inertia-driven adverse pressure gradient forming on the upstream-side of the obstacle. We contend that a similar flow structure can arise in thin-film Stokes flow around micro-obstacles, such as used in textured surfaces to improve wettability. This could be exploited to enhance mixing in microfluidic devices, typically limited to creeping-flow regimes.

Enhancement of Meniscus Pump by Multiple Particles.

We numerically investigate the behavior of a droplet spreading on a smooth substrate with multiple obstacles. As experimental works have indicated, the macroscopic contact line or the three-phase boundary line of a droplet exhibits significant deformation resulting in a local acceleration by successive interactions with an array of tiny obstacles settled on the substrate (Mu et al., ).

Pumping effect of heterogeneous meniscus formed around spherical particle.

Hypothesis: A disturbance such as a microparticle on the pathway of a spreading droplet has shown the tremendous ability to accelerate locally the motion of the macroscopic contact line (Mu et al., 2017). Although this ability has been linked to the particle-liquid interaction, the physical mechanisms behind it are still poorly understood despite its academic interest and the scope of numerous industrial applications in need of fast wetting.

Dose limits for occupational exposure to ionising radiation and genotoxic carcinogens: a German perspective.

This paper summarises the view of the German Commission on Radiological Protection ("Strahlenschutzkommission", SSK) on the rationale behind the currently valid dose limits and dose constraints for workers recommended by the International Commission on Radiological Protection (ICRP). The paper includes a discussion of the reasoning behind current dose limits followed by a discussion of the detriment used by ICRP as a measure for stochastic health effects. Studies on radiation-induced cancer are reviewed because this endpoint represents the most important contribution to detriment.

The ICRU Proposal for New Operational Quantities for External Radiation.

Report Committee 26 of the ICRU proposes a set of operational quantities for radiation protection for external radiation, directly based on effective dose and for an extended range of particles and energies. It is accompanied by quantities for estimating deterministic effects to the eye lens and the local skin. The operational quantities are designed to overcome the conceptual and technical shortcomings of those presently in use.

Dosimetric models of the eye and lens of the eye and their use in assessing dose coefficients for ocular exposures.

Based upon recent epidemiological studies of ocular exposure, the Main Commission of the International Commission on Radiological Protection (ICRP) in ICRP Publication 118 states that the threshold dose for radiation-induced cataracts is now considered to be approximately 0.5 Gy for both acute and fractionated exposures. Consequently, a reduction was also recommended for the occupational annual equivalent dose to the lens of the eye from 150 mSv to 20 mSv, averaged over defined periods of 5 years.

ICRP, 123. Assessment of radiation exposure of astronauts in space. ICRP Publication 123.

During their occupational activities in space, astronauts are exposed to ionising radiation from natural radiation sources present in this environment. They are, however, not usually classified as being occupationally exposed in the sense of the general ICRP system for radiation protection of workers applied on Earth. The exposure assessment and risk-related approach described in this report is clearly restricted to the special situation in space, and should not be applied to any other exposure situation on Earth.

Dose conversion coefficients for photon exposure of the human eye lens.

In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity H(p)(3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented.

Monitoring the eye lens: which dose quantity is adequate?

Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all.

Implications of the new ICRP recommendations for aircrew dosimetry.

In 2007 the International Commission on Radiological Protection has published its general recommendations replacing the previous 1990 Recommendations. In this paper mainly those parts of the recommendations, which may influence the assessment of doses to aircrews in flight heights, are presented and discussed. Aircrews are generally defined to be occupationally exposed workers and in many countries their exposure is assessed by determination of route doses in flight heights.

Dose conversion coefficients for electron exposure of the human eye lens.

Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all.

Angiotensin-converting enzyme in skeletal muscle: sentinel of blood pressure control and glucose homeostasis.

Recent evidence suggests a coordinated regulation by the local renin-angiotensin system (RAS) and tissue kallikrein-kinin system (TKKS) of blood flow and substrate supply in oxidative red myofibres of skeletal muscle tissue during endurance exercise. The performance of these myofibres is dependent on the increased oxidation of substrates facilitated by augmenting nutritive blood flow and glucose uptake. Humoral factors released by the contracting fibres, such as adenosine and kinins, are suggested to be responsible for this metabolic adjustment.

Dose quantities in radiation protection and their limitations.

For more than 50 years the quantity absorbed dose has been the basic physical quantity in the medical applications of ionising radiation as well as radiological protection against harm from ionising radiation. In radiotherapy relatively high doses are applied (to a part of the human body) within a short period and the absorbed dose is mainly correlated with deterministic effects such as cell killing and tissue damage. In contrast, in radiological protection one is dealing with low doses and low dose rates and long-term stochastic effects in tissue such as cancer induction.

Why it is advisable to keep wR = 1 and Q = 1 for photons and electrons.

It has been well known for a long time that the biological effectiveness of photons and electrons depends on the mean linear energy transfer (LET) of the radiation considered, e.g. (60)Co gamma rays are less effective than soft or hard X rays.

Spectra of scattered photons in large absorbers and their importance for the values of radiation weighting factor wR.

In its review of the present values of radiation weighting factor w(R) and of possible revisions of this factor, the German Radiation Protection Commission has recommended to maintain the approach of ICRP 60 to base the selection of the w(R) value for a given radiation (e.g. fission neutrons) on observed values of the relative biological effectiveness (RBE) of this radiation 'regardless of whether the reference radiation is X rays or gamma rays'.

Unveiling extracellular inorganic phosphate signals from blood in human cardiac 31P NMR spectra.

31P NMR spectra of the human heart are usually contaminated by signals that originate from blood. The main blood signals are 2,3-diphosphoglycerate (2,3-DPG), which overlap and sometimes obscure the signal of myocardial inorganic phosphate used to calculate intracellular pH and to monitor metabolic changes in the heart. In this work we demonstrate, first, that even without proton decoupling the resolution of such spectra can be high enough to evaluate intracellular inorganic phosphate of myocardium in about 70% of the spectra and, second, that extracellular inorganic phosphate from blood contributes a signal in the chemical shift region of the 2-phosphate signal of 2,3-DPG.

[Pathogenesis of coronary disease].

Being overweight (OW) was recognized very early as a risk factor for coronary heart disease (CHD). Its significance in the pathogenesis of CHD has been strengthened by observations showing that OW is responsible for the development of diabetes, hypertension and lipid disorders due to its induction of insulin resistance (IR). Its key role has been underlined further by recent studies indicating that OW causes endothelial dysfunction via elevated serum fatty acids, which initiates the molecular events that further the process of CHD.

[On pathogenesis of coronary heart disease].

Being overweight (OW) was recognized very early as a risk factor for coronary heart disease (CHD). Its significance in the pathogenesis of CHD has been strengthened by observations showing that OW is responsible for the development of diabetes, hypertension and lipid disorders due to its induction of insulin resistance (IR). Its key role has been underlined further by recent studies indicating that OW causes endothelial dysfunction via elevated serum fatty acids, which initiates the molecular events that further the process of CHD.

Monte Carlo simulation of gamma-ray response functions for a proportional counter used for neutron measurement.

It is often required in neutron calibration fields to determine the dose of gamma-rays produced in a neutron source and in the surroundings, because some neutron detectors are sensitive both to neutrons and gamma-rays. As a first step estimating neutron and gamma-ray energy spectra and fluences simultaneously in a neutron field, the gamma-ray response function for a 3He proportional counter was calculated using EGS4/PRESTA code. In the simulation, the gas multiplication factor, which depends on the detection position in the gas region along an anode wire, was taken into account to obtain the precise response function.

Augmented sympathetic response to bradykinin in the diabetic heart before autonomic denervation.

We studied whether diabetes mellitus affects the bradykinin (BK)-induced release of norepinephrine (NE) from rat cardiac sympathetic endings in situ. Three groups were studied. Group A (n=12) was rendered diabetic with streptozotocin (STZ), group B (n=13) received STZ and insulin, and group C (n=14) received citrate buffer only.

Artifacts in CSI-measurements caused by the drift of the static magnetic field.

In chemical shift resolved spectroscopic imaging (CSI) temporal changes in the static magnetic field (drift) can lead to distortions of the phase encoding process. This can result in localization artifacts. The extent of the artifact depends on the size of the drift, the number of acquisitions, as well as on the combination of the size of the field of view and the number of phase encoding gradient steps.