Superfluid liquid helium control for the primordial inflation polarization explorer balloon payload.

The Primordial Inflation Polarization Explorer (PIPER) is a stratospheric balloon payload to measure the polarization of the cosmic microwave background. Twin telescopes mounted within an open-aperture bucket dewar couple the sky to bolometric detector arrays. We reduce detector loading and photon noise by cooling the entire optical chain to 1.7 K or colder. A set of fountain-effect pumps sprays superfluid liquid helium onto each optical surface, producing helium flows of 50-100 cm3 s-1 at heights up to 200 cm above the liquid level. We describe the fountain-effect pumps and the cryogenic performance of the PIPER payload during two flights in 2017 and 2019.

Sub-Kelvin cooling for two kilopixel bolometer arrays in the PIPER receiver.

The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne telescope mission to search for inflationary gravitational waves from the early universe. PIPER employs two 32 × 40 arrays of superconducting transition-edge sensors, which operate at 100 mK. An open bucket Dewar of liquid helium maintains the receiver and telescope optics at 1.7 K. We describe the thermal design of the receiver and sub-Kelvin cooling with a continuous adiabatic demagnetization refrigerator (CADR). The CADR operates between 70 and 130 mK and provides ≈10 µW cooling power at 100 mK, nearly five times the loading of the two detector assemblies. We describe electronics and software to robustly control the CADR, overall CADR performance in flightlike integrated receiver testing, and practical considerations for implementation in the balloon float environment.

Variable-delay polarization modulators for cryogenic millimeter-wave applications.

We describe the design, construction, and initial validation of the variable-delay polarization modulator (VPM) designed for the PIPER cosmic microwave background polarimeter. The VPM modulates between linear and circular polarization by introducing a variable phase delay between orthogonal linear polarizations. Each VPM has a diameter of 39 cm and is engineered to operate in a cryogenic environment (1.5 K). We describe the mechanical design and performance of the kinematic double-blade flexure and drive mechanism along with the construction of the high precision wire grid polarizers.

Optical design of the atacama cosmology telescope and the millimeter bolometric array camera.

The Atacama Cosmology Telescope is a 6 m telescope designed to map the cosmic microwave background simultaneously at 145, 215, and 280 GHz with arcminute resolution. Each frequency will have a 32 by 32 element focal plane array of transition edge sensor bolometers. The telescope and the cold reimaging optics are optimized for millimeter-wave observations with these sensitive detectors. The design of each is described.

[From hedgehogs to men. Zoophilic dermatophytosis caused by Trichophyton erinacei in eight patients]. / Von Igeln auf Menschen. Zoophile Dermatomykose durch Trichophyton erinacei bei 8 Patienten.

The hedgehog is an in Germany previously unrecognized source of human ringworm. Eight hedgehog caretakers from Göttingen and the surrounding area developed dermatophytosis caused by Trichophyton erinacei. Four patients who handled the animals without gloves developed lesions on the hands that were more in keeping with hand eczema, leading to a delay in diagnosis. The other caretakers who wore gloves presented with typical ringworm on the arms, the big toe, the back, the abdomen, and the thighs. Their typical clinical features led to an early diagnosis and treatment.

In vivo corrosion of four magnesium alloys and the associated bone response.

Degrading metal alloys are a new class of implant materials suitable for bone surgery. The aim of this study was to investigate the degradation mechanism at the bone-implant interface of different degrading magnesium alloys in bone and to determine their effect on the surrounding bone. Sample rods of four different magnesium alloys and a degradable polymer as a control were implanted intramedullary into the femora of guinea pigs. After 6 and 18 weeks, uncalcified sections were generated for histomorphologic analysis. The bone-implant interface was characterized in uncalcified sections by scanning electron microscopy (SEM), element mapping and X-ray diffraction. Results showed that metallic implants made of magnesium alloys degrade in vivo depending on the composition of the alloying elements. While the corrosion layer of all magnesium alloys accumulated with biological calcium phosphates, the corrosion layer was in direct contact with the surrounding bone. The results further showed high mineral apposition rates and an increased bone mass around the magnesium rods, while no bone was induced in the surrounding soft tissue. From the results of this study, there is a strong rationale that in this research model, high magnesium ion concentration could lead to bone cell activation.

The use of botulinum toxin A for treatment of possible essential blepharospasm in a dog.

A 3-year-old Great Dane with bilateral possible essential blepharospasm resulting in ocular complications is described. Conservative treatment was not successful and the disease was treated with local injections of botulinum toxin A into the orbicularis oculi muscle. Blepharospasm disappeared completely 5 to 6 days after injection and did not reappear until 3 to 4 months later, at which time the injection was repeated. After several treatments over a period of more than 3 years no side effects have occured. Botulinum toxin A appeared to be effective in the treatment of essential blepharospasm in this dog.

The reduction of stealing in second graders using a group contingency.

Three clases of second graders served as subjects in this study of the effects of two types of intervention programs upon stealing: (1) an antistealing lecture with no specific contingency implied, and (2) a direct group contingency applied, whereby children were rewarded with (a) extra free time for no thefts, (b) allowed normal free time if stolen items were returned, and (c) punished with lost of free if stolen items were not returned. A multiple-baseline design across the three classes showed the group contingency to be effective in reducing stealing behavior; the anti-stealing lecture was ineffective.