Unsteady Magnetopause Reconnection Under Quasi-Steady Solar Wind Driving.

The intrinsic temporal nature of magnetic reconnection at the magnetopause has been an active area of research. Both temporally steady and intermittent reconnection have been reported. We examine the steadiness of reconnection using space-ground conjunctions under quasi-steady solar wind driving. The spacecraft suggests that reconnection is first inactive, and then activates. The radar further suggests that after activation, reconnection proceeds continuously but unsteadily. The reconnection electric field shows variations at frequencies below 10 mHz with peaks at 3 and 5 mHz. The variation amplitudes are ∼10-30 mV/m in the ionosphere, and 0.3-0.8 mV/m at the equatorial magnetopause. Such amplitudes represent 30%-60% of the peak reconnection electric field. The unsteadiness of reconnection can be plausibly explained by the fluctuating magnetic field in the turbulent magnetosheath. A comparison with a previous global hybrid simulation suggests that it is the foreshock waves that drive the magnetosheath fluctuations, and hence modulate the reconnection.

Geospace Concussion: Global Reversal of Ionospheric Vertical Plasma Drift in Response to a Sudden Commencement.

An interplanetary shock can abruptly compress the magnetosphere, excite magnetospheric waves and field-aligned currents, and cause a ground magnetic response known as a sudden commencement (SC). However, the transient (<∼1 min) response of the ionosphere-thermosphere system during an SC has been little studied due to limited temporal resolution in previous investigations. Here, we report observations of a global reversal of ionospheric vertical plasma motion during an SC on 24 October 2011 using ∼6 s resolution Super Dual Auroral Radar Network ground scatter data. The dayside ionosphere suddenly moved downward during the magnetospheric compression due to the SC, lasting for only ∼1 min before moving upward. By contrast, the post-midnight ionosphere briefly moved upward then moved downward during the SC. Simulations with a coupled geospace model suggest that the reversed E ⃗ × B ⃗ vertical drift is caused by a global reversal of ionospheric zonal electric field induced by magnetospheric compression during the SC.

Toxic effects of metal copper stress on immunity, metabolism and pathologic changes in Chinese mitten crab (Eriocheir japonica sinensis).

Copper (Cu2+), which represents a major physiological challenge for crab culture, is ubiquitous in the aquatic culture environment, and gills are the first organs that come into direct contact with the environment. However, the molecular basis of the response of crabs to Cu2+ stress remains unclear. Here, we conducted a transcriptome and differential expression analysis on the gills from Chinese mitten crab unexposed and exposed to Cu2+ for 24 h. The comparative transcriptome analysis identified 2486 differentially expressed genes (DEGs). GO functional analysis and KEGG pathway analysis revealed some DEGs, which were mostly related to immunity, metabolism, osmotic regulation, Cu2+ homeostasis regulation, antioxidant activity, and detoxification process. Some pathways related to humoral and cellular immunity, such as phagosome, peroxisome, lysosome, mTOR signaling pathway, PI3K-Akt signaling pathway, Toll-like receptor signaling pathway, and T cell receptor signaling pathway were enhanced under Cu2+ stress. In addition, Cu2+ stress altered the expression patterns of key phagocytosis and apoptosis genes (lectin, cathepsin L, Rab7, and HSP70), confirming that Cu2+ can induce oxidative stress and eventually even apoptosis. Histological analysis revealed that the copper can induce damage at the cellular level. This comparative transcriptome analysis provides valuable molecular information to aid future study of the immune mechanism of Chinese mitten crab in response to Cu2+ stress and provides a foundation for further understanding of the effects of metal toxicity.

Comparative transcriptome analysis of the gills of Procambarus clarkii provides novel insights into the immune-related mechanism of copper stress tolerance.

The red-swamp crayfish (Procambarus clarkii) is the most important economic shrimp species in China, and is an important model crustacean organism in many fields of research. In crustaceans, gills interface directly with the ambient environment and thus play a vital role in the toxicology. In the context of increasing environmental heavy metal pollution, the relationship between copper (Cu2+) stress and the immune response of P. clarkii has recently received considerable attention. However, impact of Cu2+ on the crayfish immune system is still not fully understood. In this study, we used Illumina sequencing technology to perform a transcriptome analysis of the gills of P. clarkii after 24 h of Cu2+ treatment. A total of 37,226,812 unigenes were assembled, and 1943 unigenes were significantly differentially expressed between the control and Cu2+ treatment groups. Functional categorization of differentially expressed genes (DEGs) revealed that genes related to antioxidant activity, detoxication, metabolic processes, biosynthetic processes, and immune system processes were differentially regulated during Cu2+ stress. In addition, DEGs in the immune system were classified as being related to the MAPK signaling pathway, purine metabolism, Toll and Imd signaling pathway, PI3K-Akt signaling pathway and Hippo signaling pathway. Five genes (CuZnSOD, CAT, IDH1, PHYH and DECR2) were significantly up-regulated in the peroxisome pathway, which plays an important role in reacting to oxidative stress. Importantly, qRT-PCR validation of the results for seven genes chosen at random (NDK, ATP6L, ATP5C1, RPS14, RPL22e, CTSF and HSP90A) confirmed the Illumina sequencing results. This study provides a valuable starting point for further studies to elucidate the molecular basis of the immune system's response to Cu2+ stress in crayfish.

Effect of pumping pressure on onset of lactation after caesarean section: A randomized controlled study.

Caesarean section is associated with weaker newborn suction pressure. This nonblinded, randomized trial explored the effect of suction pressures generating by a breast pump on mothers' onset of lactation and milk supply after caesarean section. A high pressure group (-150 mmHg), a low pressure group (-100 mmHg), and a control group (none) were generated under computer random assignment with concealed allocation in 2 tertiary hospitals. The breast pumping began within 2 hr after caesarean operation (6 times a day and 30 min per time) until onset of lactation. The primary outcomes were the timing of onset of lactation, milk supply, and mother's satisfaction in lactation, using both intention-to-treat and per-protocol analyses. The secondary endpoints were the pumping-related pain, nipple injury, and maternal fatigue. All 164 women randomized were included in analysis. The breast pumping at -150 mmHg optimally advanced the timing of the onset of lactation and increased daytime milk supply. The pumping also appeared to boost mothers' confidence in lactation. The results in the per-protocol population (n = 148) were consistent with those of intention-to-treat population (n = 164). However, the pumping aggravated maternal nipple pain and fatigue, though there was no statistical significance. The findings suggest that a higher pumping pressure within the range of normal vaginally born infant suction could promote onset of lactation and milk supply among mothers giving birth by caesarean section. The pumping could also enhance mothers' confidence in breastfeeding.

Efficacy and Safety of Radiotherapy Combined with Pyrotinib in the Treatment of HER2-Positive Breast Cancer with Brain Metastases.

Purpose: To explore the efficacy and safety of pyrotinib combined with different radiotherapy modes in human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) patients with brain metastasis (BM). Patients and Methods: This study is a retrospective analysis of patients diagnosed with BM who underwent treatment with pyrotinib between November 2018 and April 2023. A total of 66 patients were administered radiotherapy in conjunction with pyrotinib (Group A), while 26 patients received pyrotinib as a standalone treatment (Group B). Within Group A, 18 patients underwent conventional fractionated radiotherapy (2Gy/F), while 48 patients received hyperfractionated radiotherapy (HFRT) (≥3Gy/F). The primary endpoints were intracranial progression-free survival (IC-PFS) and overall survival (OS). The secondary endpoints were objective response rate (ORR) and clinical benefit rate (CBR). Results: The ORR of Group A was 54.5% (36/66), while the ORR of Group B was 34.6% (9/26) (P= 0.047). The CBR of Group A was 89.4% (59/66) and that of Group B was 69.2% (18/26) (P= 0.041). The IC-PFS between Group A and Group B were 12 months and 8 months, respectively (P< 0.001), and the OS were 20 months and 16 months, respectively (P= 0.065). In Group A, the IC-PFS and OS between the conventional fractionation radiotherapy group and the HFRT group were 10 months and 12 months, respectively (P= 0.001) and 16 months and 24 months, respectively (P< 0.001). No serious adverse reactions were observed in Group A and Group B. Conclusion: For HER2-positive BC patients with BM, it is recommended to adopt the treatment mode of HFRT combined with pyrotinib, which can improve the local control and survival of patients.

Effects of Subauroral Polarization Streams on the Upper Thermospheric Winds During Non-Storm Time.

Intense sunward (westward) plasma flows, named Subauroral Polarization Stream (SAPS), have been known to occur equatorward of the electron auroras for decades, yet their effect on the upper thermosphere has not been well understood. On the one hand, the large velocity of SAPS results in large momentum exchange upon each ion-neutral collision. On the other hand, the low plasma density associated with SAPS implies a low ion-neutral collision frequency. We investigate the SAPS effect during non-storm time by utilizing a Scanning Doppler Imager (SDI) for monitoring the upper thermosphere, SuperDARN radars for SAPS, all-sky imagers and DMSP Spectrographic Imager for the auroral oval, and GPS receivers for the total electron content. Our observations suggest that SAPS at times drives substantial (>50 m/s) westward winds at subauroral latitudes in the dusk-midnight sector, but not always. The occurrence of the westward winds varies with AE index, plasma content in the trough, and local time. The latitudinally averaged wind speed varies from 60 to 160 m/s, and is statistically 21% of the plasma. These westward winds also shift to lower latitude with increasing AE and increasing MLT. We do not observe SAPS driving poleward wind surges, neutral temperature enhancements, or acoustic-gravity waves, likely due to the somewhat weak forcing of SAPS during the non-storm time.

Multiresolution Modeling of High-Latitude Ionospheric Electric Field Variability and Impact on Joule Heating Using SuperDARN Data.

The most dynamic electromagnetic coupling between the magnetosphere and ionosphere occurs in the polar upper atmosphere. It is critical to quantify the electromagnetic energy and momentum input associated with this coupling as its impacts on the ionosphere and thermosphere system are global and major, often leading to considerable disturbances in near-Earth space environments. The current general circulation models of the upper atmosphere exhibit systematic biases that can be attributed to an inadequate representation of the Joule heating rate resulting from unaccounted stochastic fluctuations of electric fields associated with the magnetosphere-ionosphere coupling. These biases exist regardless of geomagnetic activity levels. To overcome this limitation, a new multiresolution random field modeling approach is developed, and the efficacy of the approach is demonstrated using Super Dual Auroral Radar Network (SuperDARN) data carefully curated for the study during a largely quiet 4-hour period on February 29, 2012. Regional small-scale electrostatic fields sampled at different resolutions from a probabilistic distribution of electric field variability conditioned on actual SuperDARN LOS observations exhibit considerably more localized fine-scale features in comparison to global large-scale fields modeled using the SuperDARN Assimilative Mapping procedure. The overall hemispherically integrated Joule heating rate is increased by a factor of about 1.5 due to the effect of random regional small-scale electric fields, which is close to the lower end of arbitrarily adjusted Joule heating multiplicative factor of 1.5 and 2.5 typically used in upper atmosphere general circulation models. The study represents an important step toward a data-driven ensemble modeling of magnetosphere-ionosphere-atmosphere coupling processes.

Geospace Plume and Its Impact on Dayside Magnetopause Reconnection Rate.

The role a geospace plume in influencing the efficiency of magnetopause reconnection is an open question with two contrasting theories being debated. A local-control theory suggests that a plume decreases both local and global reconnection rates, whereas a global-control theory argues that the global reconnection rate is controlled by the solar wind rather than local physics. Observationally, limited numbers of point measurements from spacecraft cannot reveal whether a local change affects the global reconnection. A distributed observatory is hence needed to assess the validity of the two theories. We use THEMIS and Los Alamos National Laboratory spacecraft to identify the occurrence of a geospace plume and its contact with the magnetopause. Global evolution and morphology of the plume is traced using GPS measurements. SuperDARN is then used to monitor the distribution and the strength of dayside reconnection. Two storm-time geospace plume events are examined and show that as the plume contacts the magnetopause, the efficiency of reconnection decreases at the contact longitude. The amount of local decrease is 81% and 68% for the two events, and both values are consistent with the mass loading effect of the plume if the plume's atomic mass is ∼4 amu. Reconnection in the surrounding is enhanced, and when the solar wind driving is stable, little variation is seen in the cross polar cap potential. This study illuminates a pathway to resolve the role of cold dense plasma on solar wind-magnetosphere coupling, and the observations suggest that plumes redistribute magnetopause reconnection activity without changing the global strength substantially.

Comparative transcriptome analysis in the hepatopancreas of Helice tientsinensis exposed to the toxic metal cadmium.

BACKGROUND: The mudflat crab Helice tientsinensis is one of the most commercially valuable species for crabmeat production due to its delicious taste. These crabs are mainly found in coastal wetland where they are seriously threatened by toxic heavy metal pollution. In crustaceans, the hepatopancreas is an important organ for detoxification, and metal toxic substances can be converted to non-toxic or less toxic compounds in this organ. OBJECTIVE: To develop a better understanding of the molecular response of H. tientsinensis to the toxic metal cadmium (Cd) and provide a molecular basis for the toxic metal tolerance of H. tientsinensis. METHODS: In this study, we performed comparative hepatopancreas transcriptome analysis between H. tientsinensis unexposed (as control) and exposed to the toxic metal Cd for 48 h. RESULTS: We identified 1089 Cd stress significantly-upregulated and 1560 Cd stress significantly-downregulated unigenes. Functional categorization and annotation of these differentially-expressed genes (DEGs) demonstrated that the response to Cd stress in the hepatopancreas of H. tientsinensis mainly involves "antioxidant activity", "detoxification", "toxin degradation activity" and "immune system process". In addition, five genes (ABCC1, NDUFAF5, ASTL, DES1, CYP27A) were identified as possible major targets for toxic metal tolerance. CONCLUSION: This is the first time reporting that the response of H. tientsinensis to Cd exposure at the transcriptome level, and it lays the foundation for understanding the molecular mechanisms of the response of H. tientsinensis to environmental toxic metal stress.