Plasmapause surface wave oscillates the magnetosphere and diffuse aurora.

Energy circulation in geospace lies at the heart of space weather research. In the inner magnetosphere, the steep plasmapause boundary separates the cold dense plasmasphere, which corotates with the planet, from the hot ring current/plasma sheet outside. Theoretical studies suggested that plasmapause surface waves related to the sharp inhomogeneity exist and act as a source of geomagnetic pulsations, but direct evidence of the waves and their role in magnetospheric dynamics have not yet been detected. Here, we show direct observations of a plasmapause surface wave and its impacts during a geomagnetic storm using multi-satellite and ground-based measurements. The wave oscillates the plasmapause in the afternoon-dusk sector, triggers sawtooth auroral displays, and drives outward-propagating ultra-low frequency waves. We also show that the surface-wave-driven sawtooth auroras occurred in more than 90% of geomagnetic storms during 2014-2018, indicating that they are a systematic and crucial process in driving space energy dissipation.

Equatorial aurora: the aurora-like airglow in the negative magnetic anomaly.

The most fantastic optical phenomena in the Earth's upper atmosphere are the auroras. They are highly informative indicators of solar activity, geomagnetic activity, upper atmospheric structures and dynamics, and magnetospheric energetic particles. An area where the geomagnetic field differs significantly from the expected symmetric dipole, such as at the South Atlantic Anomaly, where the magnetic field intensity is low, gives rise to stronger precipitation of energetic particles into the upper atmosphere. Impact excitation and the subsequent airglow emissions exhibit aurora-like dynamic signatures. Nomenclatures of nonpolar aurora or equatorial auroras are similar to those used with the polar auroras owing to their similar excitation mechanisms. This paper provides an overview of the knowledge and the challenges concerning auroral activity at the South Atlantic Anomaly, or more generally, at the negative magnetic anomaly. We emphasize systematic investigation of the equatorial auroras to reveal the temporal and spatial evolution of the magnetic anomaly and the behaviour of energetic particles in near-Earth space.

Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool.

Chang'E-4 landed in the South Pole-Aitken (SPA) basin, providing a unique chance to probe the composition of the lunar interior. Its landing site is located on ejecta strips in Von Kármán crater that possibly originate from the neighboring Finsen crater. A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations. In situ spectra of the regolith have peak band positions at 1 and 2 µm, similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper, which confirms that the regolith's composition of the landing area is mostly similar to that of Finsen ejecta. The rock spectrum shows similar band peak positions, but stronger absorptions, suggesting relatively fresh exposure. The rock may consist of 38.1 ± 5.4% low-Ca pyroxene, 13.9 ± 5.1% olivine and 48.0 ± 3.1% plagioclase, referred to as olivine-norite. The plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle, but representative of the lunar lower crust. Alternatively, the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle materials. This scenario is consistent with fast-cooling thermal conditions of a shallow melt pool, indicated by the fine to medium-sized texture (<3 mm) of the rock and the SPA-impact melting model [Icarus 2012; 220: 730-43].

Comparing the Differential Diagnostic Values of 18F-Alfatide II PET/CT between Tuberculosis and Lung Cancer Patients.

Purpose: To compare the differential diagnostic values of 18F-Alfatide II PET/CT between tuberculosis and lung cancer patients and in patients with sarcoidosis and common inflammation. Methods: Nine inflammation patients (4 tuberculosis, 3 sarcoidosis, and 2 common inflammation) and 11 lung cancer patients were included in this study. All patients underwent 18F-FDG and 18F-Alfatide II PET/CT within 2 weeks, followed by biopsy and surgery. The maximized standard uptake value (SUVmax) and the mean standard uptake value (SUVmean) were evaluated. Results: The active tuberculosis lesions showed a high accumulation of 18F-FDG, but varying degrees of accumulation of 18F-Alfatide II, including negative results. The SUVmax of 18F-Alfatide II in malignant lesions was significantly higher than that in tuberculosis (4.08 ± 1.51 versus 2.63 ± 1.34, P = 0.0078). Three patients with sarcoidosis showed negative results in 18F-Alfatide II PET/CT. Conclusions: The expression of αVß3 is much lower in tuberculosis as compared to that in lung cancer, and accumulation of 18F-Alfatide II varied even in lesions of the same patient. The negative results of sarcoidosis patients led to the speculation that αVß3 was not expressed in those lesions.

Ablation of Venusian oxygen ions by unshocked solar wind.

As an Earth-like planet Venus probably had a primordial dipole field for several million years after formation of the planet. Since this dipole field eventually vanished the ionosphere of Venus has been exposed to the solar wind. The solar wind is shocked near Venus, and then scavenges the ionospheric particles through the magnetosheath and the magnetotail. The escape rate of oxygen ions (O+) estimated from spacecraft observations over the past several decades has manifested its importance for the evolution of planetary habitability, considering the accumulated effect over the history of Venus. However, all the previous observations were made in the shocked solar wind and/or inside the wake, though some simulations showed that unshocked solar wind can also ablate O+ ions. Here we report Venus Express observations of O+ ions in the unshocked solar wind during the solar minimum. The observations suggest that these O+ ions are accelerated by the unshocked solar wind through pickup processes. The estimated O+ escape rate, 2.1 × 1024 ions/s, is comparable to those measured in the shocked solar wind and the wake. This escape rate could result in about 2 cm global water loss over 4.5 billion years. Our results suggest that the atmospheric loss at unmagnetized planets is significantly underestimated by previous observations, and thus we can emphasize the importance of an Earth-like dipole for planetary habitability.

Non-invasive glucagon-like peptide-1 receptor imaging in pancreas with (18)F-Al labeled Cys(39)-exendin-4.

PURPOSE: Glucagon-like peptide-1 receptor (GLP-1R) is abundantly expressed on beta cells and may be an ideal target for the pancreas imaging. Monitoring the GLP-1R of pancreas could be benefit for understanding the pathophysiology of diabetes. In the present study, (18)F-Al labeled exendin-4 analog, (18)F-Al-NOTA-MAL-Cys(39)-exendin-4, was evaluated for PET imaging GLP-1R in the pancreas. METHODS: The targeting of (18)F-Al labeled exendin-4 analog was examined in healthy and streptozotocin induced diabetic rats. Rats were injected with (18)F-Al-NOTA-MAL-Cys(39)-exendin-4 and microPET imaging was performed at 1 h postinjection, followed by ex vivo biodistribution. GLP-1R expression in pancreas was determined through post mortern examinations. RESULTS: The pancreas of healthy rats was readily visualized after administration of (18)F-Al-NOTA-MAL-Cys(39)-exendin-4, whereas the pancreas of diabetic rats, as well as those from rats co-injected with excess of unlabeled peptides, was barely visible by microPET. At 60 min postinjection, the pancreatic uptakes were 1.02 ± 0.15%ID/g and 0.23 ± 0.05%ID/g in healthy and diabetic rats respectively. Under block, the pancreatic uptakes of non-diabetic rats reduced to 0.21 ± 0.07%ID/g at the same time point. Biodistribution data and IHC staining confirmed the findings of the microPET imaging. CONCLUSION: The favorable preclinical data indicated that (18)F-Al-NOTA-MAL-Cys(39)-exendin-4may be suitable for non-invasive monitoring functional pancreatic beta cells.

Alfvén waves as a solar-interplanetary driver of the thermospheric disturbances.

Alfvén waves have been proposed as an important mechanism for the heating of the Sun's outer atmosphere and the acceleration of solar wind, but they are generally believed to have no significant impact on the Earth's upper atmosphere under quiet geomagnetic conditions due to their highly fluctuating nature of interplanetary magnetic field (i.e., intermittent southward magnetic field component). Here we report that a long-duration outward propagating Alfvén wave train carried by a high-speed stream produced continuous (~2 days) and strong (up to ± 40%) density disturbances in the Earth's thermosphere in a way by exciting multiple large-scale gravity waves in auroral regions. The observed ability of Alfvén waves to excite large-scale gravity waves, together with their proved ubiquity in the solar atmosphere and solar wind, suggests that Alfvén waves could be an important solar-interplanetary driver of the global thermospheric disturbances.

Pilot Prospective Evaluation of (18)F-Alfatide II for Detection of Skeletal Metastases.

This pilot prospective evaluation study is to verify the efficiency of (18)F-Alfatide II, a specific PET imaging agent for integrin αvß3, in detecting bone metastasis in human, with comparison to (18)F-FDG PET. Thirty recruited patients underwent (18)F-FDG and (18)F-alfatide II PET/CT successively within days. The final diagnosis of bone lesions was established based on the comprehensive assessment of all available data and clinical follow-up, which fall into four groups: osteolytic, osteoblastic, mixed and bone marrow. Visual analysis and quantification of SUVmax were performed to compare the detection sensitivity of (18)F-Alfatide II and (18)F-FDG PET. Eleven patients were found to have a total of 126 bone metastasis lesions. (18)F-Alfatide II PET can detect the bone metastatic lesions with good contrast and higher sensitivity (positive rate of 92%) than (18)F-FDG PET (77%). Especially, (18)F-Alfatide II PET showed superiority to (18)F-FDG PET in detecting osteoblastic (70% vs. 53%) and bone marrow metastatic lesions (98% vs. 77%). In conclusion, (18)F-Alfatide II PET/CT can be used to detect skeletal and bone marrow metastases, with nearly 100% sensitivity in osteolytic, mixed and bone marrow lesions. The sensitivity of (18)F-Alfatide II PET/CT in osteoblastic metastases is relatively low but still significantly higher than that of (18)F-FDG PET/CT. This pilot clinical study warrants the further application of (18)F-Alfatide II PET/CT in metastatic lesion detection, patient management and drug therapy response monitoring.

(18)F-Alfatide II PET/CT in healthy human volunteers and patients with brain metastases.

PURPOSE: We report the biodistribution and radiation dosimetry of an integrin αvß3 specific PET tracer (18)F-AlF-NOTA-E[PEG4-c(RGDfk)]2) (denoted as (18)F-Alfatide II). We also assessed the value of (18)F-Alfatide II in patients with brain metastases. METHODS: A series of torso (from the skull to the thigh) static images were acquired in five healthy volunteers (3 M, 2 F) at 5, 10, 15, 30, 45, and 60 min after injection of (18)F-Alfatide II (257 ± 48 MBq). Regions of interest (ROIs) were drawn manually, and the time-activity curves (TACs) were obtained for major organs. Nine patients with brain metastases were examined by static PET imaging with (18)F-FDG (5.55 MBq/kg) and (18)F-Alfatide II. RESULTS: Injection of (18)F-Alfatide II was well tolerated in all healthy volunteers, with no serious tracer-related adverse events found. (18)F-Alfatide II showed rapid clearance from the blood pool and kidneys. The total effective dose equivalent (EDE) and effective dose (ED) were 0.0277 ± 0.003 mSv/MBq and 0.0198 ± 0.002 mSv/MBq, respectively. The organs with the highest absorbed dose were the kidneys and the spleen. Nine patients with 20 brain metastatic lesions identified by MRI and/or CT were enrolled in this study. All 20 brain lesions were visualized by (18)F-Alfatide II PET, while only ten lesions were visualized by (18)F-FDG, and 13 by CT. CONCLUSION: F-Alfatide II is a safe PET tracer with a favorable dosimetry profile. The observed ED suggests that (18)F-Alfatide II is feasible for human studies. (18)F-Alfatide II has potential value in finding brain metastases of different cancers as a biomarker of angiogenesis.

Carcinosarcoma of the uterine corpus on 18F-FDG PET/CT in a postmenopausal woman with elevated AFP.

Uterine carcinosarcoma (termed malignant mixed müllerian tumor) is a rare neoplasm of the uterus with a poor prognosis. There have been very few cases in the literature describing the PET/CT findings of uterine carcinosarcoma. We report a case of tissue-proven carcinosarcoma of the uterine corpus in a 65-year-old woman with elevated serum alpha-fetoprotein (AFP), whose 18F-FDG PET/CT showed a 10.3-cm mass in the uterus with uneven high FDG uptake. The SUVmax was 12.8. After surgery, the patient received 6 courses of chemotherapy, and the serum levels of AFP decreased to reference range.

First experience of 18F-alfatide in lung cancer patients using a new lyophilized kit for rapid radiofluorination.

UNLABELLED: (18)F-FPPRGD2, which was approved for clinical study recently, has favorable properties for integrin targeting and showed potential for antiangiogenic therapy and early response monitoring. However, the time-consuming multiple-step synthesis may limit its widespread applications in the clinic. In this study, we developed a simple lyophilized kit for labeling PRGD2 peptide ((18)F-AlF-NOTA-PRGD2, denoted as (18)F-alfatide) using a fluoride-aluminum complex that significantly simplified the labeling procedure. METHODS: Nine patients with a primary diagnosis of lung cancer were examined by both static and dynamic PET imaging with (18)F-alfatide, and 1 tuberculosis patient was investigated using both (18)F-alfatide and (18)F-FDG imaging. Standardized uptake values were measured in tumors and other main organs at 30 min and 1 h after injection. Kinetic parameters were calculated by Logan graphical analysis. Immunohistochemistry and staining intensity quantification were performed to confirm the expression of integrin α(v)ß(3). RESULTS: Under the optimal conditions, the whole radiosynthesis including purification was accomplished within 20 min with a decay-corrected yield of 42.1% ± 2.0% and radiochemical purity of more than 95%. (18)F-alfatide PET imaging identified all tumors, with mean standardized uptake values of 2.90 ± 0.10. Tumor-to-muscle and tumor-to-blood ratios were 5.87 ± 2.02 and 2.71 ± 0.92, respectively. CONCLUSION: (18)F-alfatide can be produced with excellent radiochemical yield and purity via a simple, 1-step, lyophilized kit. PET scanning with (18)F-alfatide allows specific imaging of αvß3 expression with good contrast in lung cancer patients. This technique might be used for the assessment of angiogenesis and for planning and response evaluation of cancer therapies that would affect angiogenesis status and integrin expression levels.

[The value of extra-lung lesions on ¹8F-FDG PET/CT in improving diagnosis of lung cancer].

BACKGROUND AND OBJECTIVE: ¹8F-FDG PET/CT has several shortcomings in discriminating between lung carcinoma and pulmonary benign lesions. The aims of the present study is to explore the value of extra-lung lesions on ¹8F-FDG PET/CT image in the diagnosis of lung cancer. METHODS: A total of 126 suspected lung cancer patients underwent ¹8F-FDG PET/CT scan. Preliminary diagnoses were based on the PET characteristics, SUVmean value, and CT characteristics of the lesions in the lung, and the diagnoses were modified based on the detected extra-lung lesions. The difference between the two methods and their disparity were calculated. RESULTS: Extra-lung lesions were identified on the PET/CT image in 81 patients; extra-lung metastasis modified 13 probable malignancies to affirmative malignancy and 1 probable malignancy to benign lesion. Non-metastasis modified 2 probable malignancies to affirmative malignancy and 1 probable malignancy to benign lesion. Fifteen were correct, whereas 2 were misdiagnosed. The diagnoses modification rate was 13.5% (17/126), and the modified diagnoses accuracy is 88.2% (15/17). CONCLUSIONS: Extra-lung lesions demonstrated on ¹8F-FDG PET/CT improved the diagnostic accuracy of lung cancer. Tuberculosis was identified as the most important reason for false positive diagnoses after modification by extra-lung lesions.

Evaluation of the relationship between [18F]FDG and P-glycoprotein expression: an experimental study.

INTRODUCTION: P-glycoprotein (P-gp) is a cell-membrane-associated protein that transports a variety of drug substrates. We sought to evaluate the relationship between 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) and P-gp expression using breast carcinoma Bcap37/multidrug resistant (MDR1) and Bcap37 in vitro and in vivo. METHODS: The function of P-gp expressed in Bcap37/MDR1 cells was evaluated using verapamil (VER), a classical inhibitor of P-gp. The accumulation of 99mTc-methoxyisobutylisonitrile ([99mTc]MIBI) in vitro was measured. In vivo imaging of severe combined immune deficiency (SCID) mice implanted with Bcap37 and Bcap37/MDR1 cells was performed by scintigraphy and micro-positron emission tomography (PET). RESULTS: The uptake of [99mTc]MIBI was 0.62%±0.05% in the Bcap37/MDR1 cells and 2.02%±0.28% in the Bcap37 cells. VER significantly increased the uptake of [99mTc]MIBI in the Bcap37/MDR1 cells (1.90%±0.09%) but not in the Bcap37 cells (2.15%±0.27%). In vivo, neither the Bcap37 nor Bcap37/MDR1 tumors grown in the SCID mice could be detected by [99mTc]MIBI scintigraphy. Both the Bcap37 and Bcap37/MDR1 tumors were visible by micro-PET. The mean standardized uptake value (SUV) was significantly higher in the Bcap37 tumors (1.00±0.06) than in the Bcap37/MDR1 (0.67±0.11) tumors. VER significantly increased the mean SUV in the Bcap37/MDR1 tumors (1.02±0.16) but not in the Bcap37 tumors (1.09±0.22). CONCLUSIONS: [18F]FDG combined with VER may be an effective noninvasive method of determining P-gp expression in tumors.

[Effect and mechanism of recombinant hirudin on fibrinolysis].

AIM: To study the effect of recombinant hirudin (rH) on tPA-induced fibrinolysis and the possible mechanism of its action. METHODS: The effect of rH on thrombin-fibrin complex (Th-Fn) was detected by 99mTc labeled rH. In the in vitro clot lysis, tPA as plasminogen activator, and recalcified plasma as plasminogen resource were used to study the influence of rH on fibrinolysis by detecting TAFIa, D-Dimer and FXIII. RESULTS: In a canine model of femoral artery thrombosis, a clear radioactivity strip was imaged in 30 - 60 min on a part image, and the femoral vein thrombosis developed at 30 min. rH efficiently inhibited clot regeneration. Addition of TM could inhibit clot lysis obviously, and CPI could shorten the delay of clot lysis which due to TAFIa. There was a dose-dependent relationship with TM concentration and TAFI activation. FXIII activation was inhibited by low concentration of rH ( < or = 0.2 u x mL(-1)), and the level of fibrinolysis product, D-Dimer, increased. CONCLUSION: rH could inhibit the thrombin binding to fibrin. rH inhibited the activation of TAFI and FXIII by combining with thrombin which resulted in enhancement of thrombolysis.