Results from the Radiation Assessment Detector on the International Space Station, Part 2: The fast neutron detector.

We report the results of the first six years of measurements of so-called fast neutrons on the International Space Station (ISS) with the Radiation Assessment Detector (ISS-RAD), spanning the period from February 2016 to February 2022. ISS-RAD combines two sensor heads, one nearly identical to the single sensor head in the Mars Science Laboratory RAD (MSL-RAD). The latter is described in a companion article to this one. The novel sensor is the FND, or fast neutron detector, designed to measure neutrons with energies in the range from 200 keV to about 8 MeV. ISS-RAD was deployed in February 2016 in the USLAB module, and then served as a survey instrument from March 2017 until May 2020. Data were acquired in Node3, the Japanese Pressurized Module, Columbus, and Node2. At the conclusion of the survey portion of RAD's planned 10-year campaign on ISS, the instrument was stationed in the USLAB; current plans call for it to remain there indefinitely. The radiation environment on the ISS consists of a complex mix of charged and neutral particles that varies on short time scales owing to the Station's orbit. Neutral particles, and neutrons in particular, are of concern from a radiation protection viewpoint, because they are both highly penetrating (since they do not lose energy via direct ionization) and, at some energies, have high biological effectiveness. Neutrons are copiously produced by GCRs and other incident energetic particles when they undergo nuclear interactions in shielding. As different ISS modules have varying amounts of shielding, they also have varying neutron environments. We report results for neutron fluences and dose equivalent rates in various positions in the ISS.

Measurements of radiation quality factor on Mars with the Mars Science Laboratory Radiation Assessment Detector.

We report the first long-term measurements of the radiation quality factor of energetic charged particles on the surface of Mars. The Radiation Assessment Detector (RAD) aboard the Mars Science Laboratory rover, also known as Curiosity, has been operating on Mars since 2012. RAD contains thin silicon detectors that record the ionization energy loss of energetic charged particles. The particles are dominantly galactic cosmic rays (GCRs) and the products of their interactions in the Martian atmosphere, with occasional contributions from solar energetic particles (SEPs). The quality factor on the surface of Mars is influenced by two factors: variations in the shielding provided by the atmosphere, and changes in the spectrum of the incident energetic particle flux due to the 11-year solar cycle. The two cannot be easily disentangled using the data alone, but insights can be gained from calculations and Monte Carlo simulations.

Imidazo[5,1-f][1,2,4]triazin-2-amines as novel inhibitors of polo-like kinase 1.

The synthesis and biological activities of imidazo[5,1-f][1,2,4]triazin-2-amines (imidazotriazines) as novel polo-like kinase 1 inhibitors are reported.

Tularaemia in southwest Germany: Three cases of tick-borne transmission.

Tularaemia, caused by Francisella tularensis, is an endemic zoonosis frequently occurring in southwest Germany. Since 2005 there is an increase in the number of reported cases of tularaemia in Germany. We report on two cases of ulceroglandular tularaemia and one case of glandular tularaemia that occurred in the summer of 2012 and 2013 in two counties in the Federal State of Baden-Wuerttemberg. Bacteria were transmitted through tick bites, which to date has only rarely been reported in Germany. Inadequate treatment of the patients and an aggravation of clinical symptoms were caused by a delay between disease onset and the detection of the pathogen. Although contact to or consumption of infected hares are the most often reported transmission routes of tularaemia in Germany, tick-bites should also be taken into account. Health professionals should include Francisella tularensis in the differential diagnosis of patients with fever and/or ulcerative lymphadenopathy following a tick bite.

Measurements of the neutron spectrum in transit to Mars on the Mars Science Laboratory.

The Mars Science Laboratory spacecraft, containing the Curiosity rover, was launched to Mars on 26 November 2011. Although designed for measuring the radiation on the surface of Mars, the Radiation Assessment Detector (RAD) measured the radiation environment inside the spacecraft during most of the 253-day, 560-million-kilometer cruise to Mars. An important factor for determining the biological impact of the radiation environment inside the spacecraft is the specific contribution of neutrons with their high biological effectiveness. We apply an inversion method (based on a maximum-likelihood estimation) to calculate the neutron and gamma spectra from the RAD neutral particle measurements. The measured neutron spectrum (12-436 MeV) translates into a radiation dose rate of 3.8±1.2 µGy/day and a dose equivalent of 19±5 µSv/day. Extrapolating the measured spectrum (0.1-1000 MeV), we find that the total neutron-induced dose rate is 6±2 µGy/day and the dose equivalent rate is 30±10 µSv/day. For a 360 day round-trip from Earth to Mars with comparable shielding, this translates into a neutron induced dose equivalent of about 11±4 mSv.

Structural features and biochemical properties of TNF-alpha converting enzyme (TACE).

Tumor necrosis factor-alpha is a potent cytokine, secreted primarily by activated monocytes and macrophages, that possesses a broad range of immunomodulating properties. Involvement of this cytokine has been validated in disease states such as arthritis and Crohn's disease and implicated in diverse neuroimmunological pathologies such as multiple sclerosis, Alzheimers and stroke. TNF-alpha is initially synthesized as a 26 kDa precursor molecule that is subsequently processed to the mature form by cleavage of the Ala76 Val77 bond. The 17 kDa carboxy-terminal protein is then secreted to function in a paracrine manner. The enzyme that processes precursor TNF-alpha has previously been identified as a microsomal metalloprotease called TNF-alpha converting enzyme (TACE). We have now purified and partially cloned the enzyme. TACE represents a novel target for therapeutic intervention in a variety of inflammatory and neuroimmunological diseases.

Tick infestation patterns and prevalence of Borrelia burgdorferi in ticks collected at a veterinary clinic in Germany.

A total of 4803 domestic and wild animals which were presented for examination at a veterinary clinic in north Baden, Germany over a period of 1 year were examined for tick infestation. A total of 434 nymphal and adult ticks were collected from 175 hosts. Ticks found belonged to the species Ixodes ricinus (385), Ixodes hexagonus (48), and Ixodes ventalloi (one). The polymerase chain reaction was used to examine 132 I. ricinus and 21 I. hexagonus for the presence of Borrelia burgdorferi. Twenty-two per cent of adult I. ricinus were infected as were one female and one larval I. hexagonus.

In situ radiometric and exposure age dating of the martian surface.

We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 ± 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray-produced (3)He, (21)Ne, and (36)Ar yield concordant surface exposure ages of 78 ± 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation.

Measurements of energetic particle radiation in transit to Mars on the Mars Science Laboratory.

The Mars Science Laboratory spacecraft, containing the Curiosity rover, was launched to Mars on 26 November 2011, and for most of the 253-day, 560-million-kilometer cruise to Mars, the Radiation Assessment Detector made detailed measurements of the energetic particle radiation environment inside the spacecraft. These data provide insights into the radiation hazards that would be associated with a human mission to Mars. We report measurements of the radiation dose, dose equivalent, and linear energy transfer spectra. The dose equivalent for even the shortest round-trip with current propulsion systems and comparable shielding is found to be 0.66 ± 0.12 sievert.

[Measurement of blood flow velocity, blood volume flow and arterial cross section using the integral Doppler ultrasonic method--comparison and synthesis of two solutions]. / Messung der Blutgeschwindigkeit, des Blut-Volumenstromes und der Aderquerschnittsfläche nach der integralen Ultraschall-Dopplermethode--Vergleich und Synthese zweier Lösungen.

Starting with a short comparison of the space resolving, pulsed Doppler method with the integral Doppler techniques for blood flow measurement, the formula is derived, after which the profile independent cross-sectional mean velocity v is to be measured using the integral method. When evaluating the Doppler signal power, moreover, volume flow Q can be measured. Two versions of the integral method for volume flow Q, one with (WAVUD) and the other without (WUVUD), and the need for a separate determination of the angle of incidence are explained and compared. Combination of the two results in a new method for measuring the mean velocity v and cross-sectional area F of blood flow from one single sound direction, without the need for determining the angle of sound incidence into the artery. The main problems of the integral method are addressed and in vitro test results are reported, showing that 20% measurement accuracy should be practical in vivo.

[Measuring blood flow velocity, blood volume flow and arterial diameter using integral Doppler ultrasound--comparison and synthesis of 2 solutions]. / Messung der Blutgeschwindigkeit, des Blut-Volumenstromes und der Aderquerschnittsfläche nach der integralen Ultraschall-Dopplermethode--Vergleich und Synthese zweier Lösungen.

Starting with a short comparison of the space resolving, pulsed Doppler method with the integral Doppler techniques for blood flow measurement, the formula is derived, after which the profile independent cross-sectional mean velocity v is to be measured using the integral method. When evaluating the Doppler signal power, moreover, volume flow Q can be measured. Two versions of the integral method for volume flow Q, one with (WAVUD) and the other without (WUVUD), and the need for a separate determination of the angle of incidence are explained and compared. Combination of the two results in a new method for measuring the mean velocity v and cross-sectional area F of blood flow from one single sound direction, without the need for determining the angle of sound incidence into the artery. The main problems of the integral method are addressed and in vitro test results are reported, showing that 20% measurement accuracy should be practical in vivo.

[Systems theory of pulsed Doppler ultrasound technic in the determination of blood flow. III]. / Beitrag zur Systemtheorie der Ultraschall-Puls-Doppler-Technik zur Blutströmungsmessung. III. Teil.

Following the discussion of the signal-generation of an ideal pw Doppler system in part 1 and the derivation of expressions for the system parameters space resolution and unambiguity range in part 2, this part 3 deals with the velocity--or frequency--resolution (uncertainty-principle) of the pw Doppler system.

[Systems theory of the pulsed Doppler technic for blood flow measurement. II]. / Beitrag zur Systemtheorie der Ultraschall-Puls-Doppler-Technik zur Blutströmungsmessung. II. Teil.

Following the discussion of the signal generation of an ideal pw Doppler system in the time and frequency domain using the means of the one-dimensional system theory in part 1 in this part 2 the main system parameters as resolution in space, and unambiguity ranges for space and velocity are explained and mathematical formula are derived for this.

[Systems theory of the ultrasound pulsed Doppler technic for measuring blood flow. I]. / Beitrag zur Systemtheorie der Ultraschall-Puls-Doppler-Technik zur Blutströmungsmessung. I. Teil.

Part 1 presents the signal generation of an ideal pwDoppler system in the time and frequency domain using the means of the one-dimensional system theory. Problems of realisation are ignored, but tissue properties like absorption and scattering are taken into consideration. A comparison is made with pulse echo signals from tissue.

[Systems theory of ultrasound pulse echo technic (1)]. / Beitrag zur Systemtheorie der Ultraschall-Puls-Echo-Technik (Teil 1).

The properties of diagnostic pulse echo systems, independent of instrument characteristics (ideal system) are analysed in Part 1 and it is shown in Part 2 how they are modified by "typical" instrument parameters. A simplified block diagram of an ideal system is analysed in the time and frequency domain by means of the one-dimensional system theory. The terms dynamic range, maximum penetration depth and amplitude resolution are explained.

[Systems theory of ultrasound pulse echo technic (2)]. / Beitrag zur Systemtheorie der Ultraschall-Puls-Echo-Technik (Teil 2).

Part two explains the terms, spatial resolution, range ambiguity and maximum frame rate of diagnostic pulse echo systems. Then the idealised system described in part one is completed by incorporating various band pass filters, which represent the effects of resonant piezoelectric transducers and electric filters of the TGC amplifiers. The influence of such band limiting components on spatial resolution and dynamic range are shown by numerical examples. Mathematical derivations are restricted to the necessary minimum and all formulae are illustrated by means of a substantial number of graphs.

Value of in-line and out-of-line ultrasound targeting in extracorporeal shock wave lithotripsy.

Acoustic inhomogeneities of body tissue may deflect diagnostic ultrasound waves as well as therapeutic shock waves. The influence of incorrect ultrasound targeting and shock wave application due to these deflection effects has been examined quantitatively by means of a two-dimensional physical model. The accuracy of in-line and out-of-line targeting has been determined. Calculations on 2 stone patients show that in-line deflection effects remain below 2 mm, while they reach values up to 6 mm for out-of-line systems. These results, confirmed by first clinical observations done by others, indicate that in-line ultrasound targeting is superior to out-of-line targeting.