Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
LanguageLanguage
-
SubjectSubject
-
Item TypeItem Type
-
DisciplineDiscipline
-
YearFrom:-To:
-
More FiltersMore FiltersIs Peer Reviewed
Done
Filters
Reset
52
result(s) for
"Lyu, Huimin"
Sort by:
Charge Structure and Lightning Discharge in a Thunderstorm Over the Central Tibetan Plateau
2024
The evolution of charge structure involved in lightning discharge of a thunderstorm over the central Tibetan Plateau is investigated for the first time, based on the data from very high frequency interferometer, radar and sounding. During the developing‐mature stage, the TP thunderstorm exhibited a tripolar charge structure evolved from an initial inverted dipole. At the mature stage, a bottom‐heavy tripole charge structure is clearly presented, with a strong lower positive charge center (LPCC) at temperatures above −10°C, a middle negative charge region between −30°C and −15°C, and an upper positive charge region at T < −30°C. As the LPCC was depleted, the charge structure evolved into a normal tripole with a pocket LPCC. The merging between different convective cells resulted in the formation of two adjacent negative charge regions located directly and obliquely above the LPCC, and horizontally arranged different charge regions were simultaneously involved in the same lightning discharge. Plain Language Summary Tibetan Plateau thunderstorms usually exhibit special convective structures. Using the data from the accurate lightning VHF interferometer, electric field mill, fast/slow antenna and C‐band radar, the evolution of the charge structure of thunderstorms and their influence on lightning discharges are investigated. Our observation for the first time revealed the charge structure evolution of the central‐TP thunderstorm which involved in the lightning discharge, exhibiting a bottom heavy tripole charge structure with a large LPCC in the mature stage evolved from an initial inverted dipole and the usual tripole in the dissipating stage of the thunderstorm. Under different magnitudes of the LPCC, different types of lightning discharges including ‐IC, +IC and ‐CG flashes were generated, indicating the crucial effects of LPCC on the lightning discharge types. Key Points The charge structure of the TP thunderstorm evolves from an initial inverted dipole to a mature stage tripole with a strong LPCC Horizontally distributed negative charge zones from cell merger are simultaneously involved in the discharge of a single lightning flash Differences in the relative magnitude of LPCC leads to various types of lightning discharges
Journal Article
Inverted Charge Structure in a Tibetan Plateau Thunderstorm
2025
The inverted tripole charge structure in thunderstorm over the central Tibetan Plateau was discovered for the first time, primarily through observations from lightning very high frequency interferometer capable of high‐precision lightning channel mapping. The dominant cell exhibited an inverted tripole charge structure initially, characterized by a negative charge region at temperatures near 0°C, a main positive charge region between −30°C and −5°C, and an upper negative charge region at T < −20°C. The cell's rear portion exhibited a normal tripole before detaching, leaving a pure inverted tripole. Dissipation of the lower negative charge transitioned the structure to an inverted dipole, consisting of an upper negative (T < −20°C) and lower positive (T > −20°C). Throughout this thunderstorm, no positive cloud‐to‐ground (+CG) flashes were detected, while five −CG flashes were recorded. Among 109 intracloud (IC) flashes detected, 90% occurred between the upper inverted dipole. Radar reflectivity showed that this thunderstorm was more intense than conventional plateau thunderstorms.
Journal Article
Effect of GnRH analogs in advanced male breast cancer: 10-year experience from the Henan Breast Cancer Center and literature review
2024
The objective response rate (ORR) was defined as the proportion of patients with confirmed complete or partial response according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1), and the clinical benefit rate (CBR) was defined as the proportion of patients with confirmed complete response, partial response, or stable disease (≥6 months) according to RECIST 1.1. According to the St. Gallen consensus molecular categorization method for breast cancer, 17/18 of the patients in this research were positive for hormone receptors and negative for human epidermal growth factor receptor 2 (HR+/HER2–). [...]generation AIs are currently the most frequently used. According to the guidelines established by the National Comprehensive Cancer Network (NCCN), it is recommended that patients with mMBC get treatment that is comparable to that provided to postmenopausal women.
Journal Article
Comparative transcriptomic analysis validates iPSC derived in-vitro progressive fibrosis model as a screening tool for drug discovery and development in systemic sclerosis
2024
Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, immune dysregulation, and systemic fibrosis. Research on SSc has been hindered largely by lack of relevant models to study the progressive nature of the disease and to recapitulate the cell plasticity that is observed in this disease context. Generation of models for fibrotic disease using pluripotent stem cells is important for recapitulating the heterogeneity of the fibrotic tissue and are a potential platform for screening anti-fibrotic drugs. We previously reported a novel in-vitro model for fibrosis using induced pluripotent stem cell-derived mesenchymal cells (iSCAR). Here we report the generation of a “scar-like phenotype” when iPSC derived mesenchymal cells are cultured on hydrogel that mimicks a wound healing/scarring response (iSCAR). First, we performed RNA sequencing (RNA-seq) based transcriptome profiling of iSCAR culture at 48 h and 13 days to characterize early and latestage scarring phenotypes. The next generation RNA-seq of these iSCAR culture at different timepoints detected expression 92% of early “scar associated” genes and 85% late “scar associated” genes, respectively. Comparative transcriptomic analysis of a gene level SSc compendium matrix to the iSCAR wound associated model revealed genes common in both data sets. Early scar formation genes showed biological processes of hypoxia (27.5%), vascular development (13.7%) and glycolysis (27.5), while late scar formation showed genes associated with senescence (22.6%). Next we show the effects of two different antifibrotic compounds to validate the utility of the model as a screening tool to study early and late-stagelate-stage fibrosis. An autotaxin inhibitor was used to validate the iSCAR late stage fibrotic model (iSCAR-T) and an antifibrotic tool screening compound of unknown mechanism (EX00015097) was used to study and validate both early (iSCAR-P) and late-stage (iSCAR-T) fibrosis in the iSCAR model.
Journal Article
A New Hybrid Algorithm to Image Lightning Channels Combining the Time Difference of Arrival Technique and Electromagnetic Time Reversal Technique
2021
Very-high-frequency (VHF) electromagnetic signals have been well used to image lightning channels with high temporal and spatial resolution due to their capability to penetrate clouds. A lightning broadband VHF interferometer with three VHF antennas configured in a scalene-triangle shape has been installed in Lhasa since 2019, to detect the lightning VHF signals. Using the signals from the VHF interferometer, a new hybrid algorithm, called the TDOA-EMTR technique, combining the time difference of arrival (TDOA) and the electromagnetic time reversal (EMTR) technique is introduced to image the two-dimensional lightning channels. The TDOA technique is firstly applied to calculate the initial solutions for the whole lightning flash. According to the results by the TDOA method, the domain used for the EMTR technique is predetermined, and then the EMTR technique is operated to obtain the final positioning result. Unlike the original EMTR technique, the low-power frequency points for each time window are removed based on the FFT spectrum. Metrics used to filter noise events are adjusted. Detailed imaging results of a negative cloud-to-ground (CG) lightning flash and an intra-cloud (IC) lightning flash by the TDOA method and the TDOA-EMTR are presented. Compared with the original EMTR method, the positioning efficiency can be improved by more than a factor of 3 to 4, depending on the scope of the pre-determined domain. Results show that the new algorithm can obtain much weaker radiation sources and simultaneously occurring sources, compared with the TDOA method.
Journal Article
A Parallax Shift Effect Correction Based on Cloud Top Height for FY-4A Lightning Mapping Imager (LMI)
2023
The Lightning Mapping Imager (LMI) onboard the Fengyun-4A (FY-4A) satellite is the first independently developed satellite-borne lightning imager in China. It enables continuous lightning detection in China and surrounding areas, regardless of weather conditions. The FY-4A LMI uses a Charge-Coupled Device (CCD) array for lightning detection, and the accuracy of lightning positioning is influenced by cloud top height (CTH). In this study, we proposed an ellipsoid CTH parallax correction (ECPC) model for lightning positioning applicable to FY-4A LMI. The model utilizes CTH data from the Advanced Geosynchronous Radiation Imager (AGRI) on FY-4A to correct the lightning positioning data. According to the model, when the CTH is 12 km, the maximum deviation in lightning positioning caused by CTH in Beijing is approximately 0.1177° in the east–west direction and 0.0530° in the north–south direction, corresponding to a horizontal deviation of 13.1558 km, which exceeds the size of a single ground detection unit of the geostationary satellite lightning imager. Therefore, it is necessary to be corrected. A comparison with data from the Beijing Broadband Lightning Network (BLNET) and radar data shows that the corrected LMI data exhibit spatial distribution that is closer to the simultaneous BLNET lightning positioning data. The coordinate differences between the two datasets are significantly reduced, indicating higher consistency with radar data. The correction algorithm decreases the LMI lightning location deviation caused by CTH, thereby improving the accuracy and reliability of satellite lightning positioning data. The proposed ECPC model can be used for the real-time correction of lightning data when CTH is obtained at the same time, and it can be also used for the post-correction of space-based lightning detection with other cloud top height data.
Journal Article
The Impact of Intracloud Negative Branches on Continuing Current in Negative Cloud‐to‐Ground Lightning
2025
Continuing current (CC) in cloud‐to‐ground (CG) lightning plays a critical role, particularly in wildfire ignition, yet CC's mechanism remains an open question. This study analyzes six CG flashes captured by the high‐speed camera at Beijing and Lhasa, which reveal the propagation of intracloud negative leaders before and after each return stroke. While the positive leaders are invisible, obscured by the cloud, we quantified the cumulative channel extension of negative branches. We find that the short CC is linked with vigorous negative branches after the stroke, while the long CC correlates with near absence of negative branches. Assuming a stable propagation of positive leaders before and after negative strokes, the duration of CC could be controlled by the current competition between intracloud negative leaders and the stroke channel. This study provides novel insights into CC mechanisms and suggests a new method to evaluate CC duration.
Journal Article
Lateral Negative Re‐Discharges on the Negative Leader in a Positive Cloud‐to‐Ground Lightning Flash
Negative‐polarity lateral discharges on pre‐ionized negative channels during a positive cloud‐to‐ground lightning flash were captured by very high frequency interferometric observations. Prior to the return stroke (RS), as the positive leader (PL) advanced steadily and the negative leader (NL) weakened, flickering lateral re‐discharges with small scale, resembling needles on PLs, propagated toward the NL tip at approximately 8.0 × 104 m/s. Unlike needles concentrated near PL tips, these re‐discharges occurred along nearly the entire horizontal negative channel. Following the RS, both fast discharges along existing negative channels and new lateral discharges breaking into virgin air were observed, rapidly extending the negative channels and sustaining the continuing current. These re‐discharges appeared to be closely linked to channel potential variations: gradual potential changes before the RS reactivation preceded negative branches, while abrupt potential jumps after the RS initiation triggered intense axial and lateral discharges.
Journal Article
Visualizing atomic structure and magnetism of 2D magnetic insulators via tunneling through graphene
by
Qiu, Zhizhan
,
Yang, Huimin
,
Novoselov, Kostya S.
in
147/138
,
639/301/1005/1008
,
639/925/918/1052
2021
The discovery of two-dimensional (2D) magnetism combined with van der Waals (vdW) heterostructure engineering offers unprecedented opportunities for creating artificial magnetic structures with non-trivial magnetic textures. Further progress hinges on deep understanding of electronic and magnetic properties of 2D magnets at the atomic scale. Although local electronic properties can be probed by scanning tunneling microscopy/spectroscopy (STM/STS), its application to investigate 2D magnetic insulators remains elusive due to absence of a conducting path and their extreme air sensitivity. Here we demonstrate that few-layer CrI
3
(FL-CrI
3
) covered by graphene can be characterized electronically and magnetically via STM by exploiting the transparency of graphene to tunneling electrons. STS reveals electronic structures of FL-CrI
3
including flat bands responsible for its magnetic state. AFM-to-FM transition of FL-CrI
3
can be visualized through the magnetic field dependent moiré contrast in the d
I
/d
V
maps due to a change of the electronic hybridization between graphene and spin-polarised CrI
3
bands with different interlayer magnetic coupling. Our findings provide a general route to probe atomic-scale electronic and magnetic properties of 2D magnetic insulators for future spintronics and quantum technology applications.
In this work Qiu et al. demonstrate that the application of van der Waals technology to STM/STS will dramatically expand the capabilities of the latter, allowing STM/STS to investigate the structure, electronic properties and magnetism of 2D magnetic insulators at the atomic scale.
Journal Article
Primary Pulmonary Liposarcoma: A Case Report
2025
Primary liposarcoma of the lung is extremely rare. To date, only 24 cases have been reported in the English literature. Herein, we present a case of well-differentiated pulmonary liposarcoma that was misdiagnosed as teratoma on positron emission tomography/computed tomography (CT) and contrast-enhanced CT. Radical surgery with left superior lobectomy and mediastinal lymph node dissection were performed. The patient experienced recurrence and distant metastases 33 months after surgery. He was alive at the time of writing this report (36 months postoperatively). To our knowledge, this is the first case report of pulmonary well-differentiated liposarcoma.
Journal Article