Closed magnetic topology in the Venusian magnetotail and ion escape at Venus.

Venus, lacking an intrinsic global dipole magnetic field, serves as a textbook example of an induced magnetosphere, formed by interplanetary magnetic fields (IMF) enveloping the planet. Yet, various aspects of its magnetospheric dynamics and planetary ion outflows are complex and not well understood. Here we analyze plasma and magnetic field data acquired during the fourth Venus flyby of the Parker Solar Probe (PSP) mission and show evidence for closed topology in the nightside and downstream portion of the Venus magnetosphere (i.e., the magnetotail). The formation of the closed topology involves magnetic reconnection-a process rarely observed at non-magnetized planets. In addition, our study provides an evidence linking the cold Venusian ion flow in the magnetotail directly to magnetic connectivity to the ionosphere, akin to observations at Mars. These findings not only help the understanding of the complex ion flow patterns at Venus but also suggest that magnetic topology is one piece of key information for resolving ion escape mechanisms and thus the atmospheric evolution across various planetary environments and exoplanets.

Enhanced interleukin-6 in human adipose tissue vein after sprint exercise: Results from a pilot study.

BACKGROUND: Low-volume sprint exercise is likely to reduce body fat. Interleukin (IL-6) may mediate this by increasing adipose tissue (AT) lipolysis. Therefore, the exchange of AT IL-6 and glycerol, a marker of lipolysis, was examined in 10 healthy subjects performing three 30-s all-out sprints. METHODS: Blood samples were obtained from brachial artery (a) and a superficial subcutaneous vein (v) on the anterior abdominal wall up to 9 min after the last sprint and analysed for IL-6 and glycerol. RESULTS: Arterial IL-6 increased 2-fold from rest to last sprint. AT venous IL-6 increased 15-fold from 0.4 ± 0.4 at rest to 7.0 ± 4 pg × mL-1 (p < 0.0001) and AT v-a difference increased 45-fold from 0.12 ± 0.3 to 6.0 ± 5 pg x mL-1 (p < 0.0001) 9 min after last sprint. Arterial glycerol increased 2.5-fold from rest to 9 min postsprint 1 (p < 0.0001) and was maintained during the exercise period. AT venous and v-a difference of glycerol increased 2-fold from rest to 9 min postsprint 1 (p < 0.0001 and p = 0.01, respectively), decreased until 18 min postsprint 2 (p < 0.001 and p < 0.0001), and then increased again until 9 min after last sprint (both p < 0.01). CONCLUSIONS: The concurrent increase in venous IL-6 and glycerol in AT after last sprint is consistent with an IL-6 induced lipolysis in AT. Glycerol data also indicated an initial increase in lipolysis after sprint 1 that was unrelated to IL-6. Increased IL-6 in adipose tissue may, therefore, complement other sprint exercise-induced lipolytic agents.

Detection of magnetospheric ion drift patterns at Mars.

Mars lacks a global magnetic field, and instead possesses small-scale crustal magnetic fields, making its magnetic environment fundamentally different from intrinsic magnetospheres like those of Earth or Saturn. Here we report the discovery of magnetospheric ion drift patterns, typical of intrinsic magnetospheres, at Mars using measurements from Mars Atmosphere and Volatile EvolutioN mission. Specifically, we observe wedge-like dispersion structures of hydrogen ions exhibiting butterfly-shaped distributions (pitch angle peaks at 22.5°-45° and 135°-157.5°) within the Martian crustal fields, a feature previously observed only in planetary-scale intrinsic magnetospheres. These dispersed structures are the results of drift motions that fundamentally resemble those observed in intrinsic magnetospheres. Our findings indicate that the Martian magnetosphere embodies an intermediate case where both the unmagnetized and magnetized ion behaviors could be observed because of the wide range of strengths and spatial scales of the crustal magnetic fields around Mars.

Direct evidence of substorm-related impulsive injections of electrons at Mercury.

Mercury's magnetosphere is known to involve fundamental processes releasing particles and energy like at Earth due to the solar wind interaction. The resulting cycle is however much faster and involves acceleration, transport, loss, and recycling of plasma. Direct experimental evidence for the roles of electrons during this cycle is however missing. Here we show that in-situ plasma observations obtained during BepiColombo's first Mercury flyby reveal a compressed magnetosphere hosts of quasi-periodic fluctuations, including the original observation of dynamic phenomena in the post-midnight, southern magnetosphere. The energy-time dispersed electron enhancements support the occurrence of substorm-related, multiple, impulsive injections of electrons that ultimately precipitate onto its surface and induce X-ray fluorescence. These observations reveal that electron injections and subsequent energy-dependent drift now observed throughout Solar System is a universal mechanism that generates aurorae despite the differences in structure and dynamics of the planetary magnetospheres.

Synergies Between Venus & Exoplanetary Observations: Venus and Its Extrasolar Siblings.

Here we examine how our knowledge of present day Venus can inform terrestrial exoplanetary science and how exoplanetary science can inform our study of Venus. In a superficial way the contrasts in knowledge appear stark. We have been looking at Venus for millennia and studying it via telescopic observations for centuries. Spacecraft observations began with Mariner 2 in 1962 when we confirmed that Venus was a hothouse planet, rather than the tropical paradise science fiction pictured. As long as our level of exploration and understanding of Venus remains far below that of Mars, major questions will endure. On the other hand, exoplanetary science has grown leaps and bounds since the discovery of Pegasus 51b in 1995, not too long after the golden years of Venus spacecraft missions came to an end with the Magellan Mission in 1994. Multi-million to billion dollar/euro exoplanet focused spacecraft missions such as JWST, and its successors will be flown in the coming decades. At the same time, excitement about Venus exploration is blooming again with a number of confirmed and proposed missions in the coming decades from India, Russia, Japan, the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). Here we review what is known and what we may discover tomorrow in complementary studies of Venus and its exoplanetary cousins.

A single-step competitive binding assay for mapping of single DNA molecules.

Optical mapping of genomic DNA is of relevance for a plethora of applications such as scaffolding for sequencing and detection of structural variations as well as identification of pathogens like bacteria and viruses. For future clinical applications it is desirable to have a fast and robust mapping method based on as few steps as possible. We here demonstrate a single-step method to obtain a DNA barcode that is directly visualized using nanofluidic devices and fluorescence microscopy. Using a mixture of YOYO-1, a bright DNA dye, and netropsin, a natural antibiotic with very high AT specificity, we obtain a DNA map with a fluorescence intensity profile along the DNA that reflects the underlying sequence. The netropsin binds to AT-tetrads and blocks these binding sites from YOYO-1 binding which results in lower fluorescence intensity from AT-rich regions of the DNA. We thus obtain a DNA barcode that is dark in AT-rich regions and bright in GC-rich regions with kilobasepair resolution. We demonstrate the versatility of the method by obtaining a barcode on DNA from the phage T4 that captures its circular permutation and agrees well with its known sequence.