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"Xiao, S."
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Transformation, migration and outcome of residual bodies in the seminiferous tubules of the rat testis
Summary Experiments were performed to study the transformation, migration and outcome of residual bodies (RBs) in the seminiferous tubules of the rat testes. One part of the testes from adult Sprague–Dawley rats was used to generate paraffin sections to observe RBs and RB precursors through specific staining, and the other part of the testes was used to generate ultrathin sections to observe RBs under a transmission electron microscope. Deep blue particles of different sizes were observed in some seminiferous tubules through specific staining for RBs and RB precursors. These particles first appeared in the seminiferous tubules at stage I of the spermatogenic cycle, and after spermiation, the particles travelled rapidly towards the deeper region of the seminiferous epithelium and soon appeared close to the basement membrane of the seminiferous tubule. All of the particles in the tubules disappeared at stage IX. Using transmission electron microscopy, components of different electron densities were observed in the RBs on the surface of the seminiferous epithelium, all of which gradually formed in the cytoplasm of spermatozoon in later stages of spermiogenesis. After the spermatozoa were released, the RBs in the epithelium travelled quickly to the edge of the tube and were gradually transformed into lipid inclusions. These lipid inclusions ultimately became lipidlike particles. The lipidlike particles were discharged into the interstitial tissue. RBs initiate their own digestive process before their formation during spermiation in the rat testes. After spermiation, the RBs transform into lipid inclusions and finally into lipidlike particles. These lipidlike particles can be eliminated from the seminiferous tubules.
Journal Article
Planar refraction and lensing of highly confined polaritons in anisotropic media
Refraction between isotropic media is characterized by light bending towards the normal to the boundary when passing from a low- to a high-refractive-index medium. However, refraction between anisotropic media is a more exotic phenomenon which remains barely investigated, particularly at the nanoscale. Here, we visualize and comprehensively study the general case of refraction of electromagnetic waves between two strongly anisotropic (hyperbolic) media, and we do it with the use of nanoscale-confined polaritons in a natural medium: α-MoO
3
. The refracted polaritons exhibit non-intuitive directions of propagation as they traverse planar nanoprisms, enabling to unveil an exotic optical effect: bending-free refraction. Furthermore, we develop an in-plane refractive hyperlens, yielding foci as small as λ
p
/6, being λ
p
the polariton wavelength (λ
0
/50 compared to the wavelength of free-space light). Our results set the grounds for planar nano-optics in strongly anisotropic media, with potential for effective control of the flow of energy at the nanoscale.
Refraction between anisotropic media is still an unexplored phenomenon. Here, the authors investigate the propagation of hyperbolic phonon polaritons traversing α-MoO3 nanoprisms, showing a bending-free refraction effect and sub-diffractional focusing with foci size as small as 1/50 of the light wavelength in free space.
Journal Article
A multi-layer metallic structure based on phase cancellation for wideband RCS reduction
In this article, a multi-layer metallic structure based on phase cancellation for wideband radar cross-section (RCS) reduction is proposed. Firstly, the process of perfect electric conductors (PECs) positioned at different heights to generate reflected waves with different phases, ultimately achieving phase cancellation and RCS reduction, is investigated. Secondly, the accumulative nature of phase cancellation is studied, which advances understanding on phase cancellation and provides new a way for wideband RCS reduction. The proposed multi-layer metallic structure is simulated, which offers at least a fractional bandwidth of 122.2% (2.1 GHz-8.7 GHz) with 10 dB RCS reduction. A good agreement between the calculated and simulated results validates the proposed design.
Journal Article
Assessment of Erosion Wear on a Reducing Pipe in a Propulsion System Using the Eulerian-Lagrangian Method
The erosion wear on a forcing cone (FC), which is a reducing pipe structure in a barrel, is a transient complicated process that is caused by a high-speed dense propellant particle group. This process leads to the reduced propulsive performance and shortened useful life of a propulsion system. The accurate evaluation of this phenomenon is a formidable task. In this study, an effective evaluation model is developed to tackle this challenge, where the initial interior ballistic model is integrated into a computational fluid dynamics and discrete element method (CFD-DEM) coupling framework to reproduce the propellant gas source. The detailed particle interactions are factored into the model to enhance the precision. The results show that a gushing phenomenon exists when the particles move in the FC. The main interaction between the particles and the wall gradually changes from an impact interaction to a friction interaction. The erosion loss mass increases exponentially over time. Finally, the erosion distribution varies from an annular irregular distribution to a cloud-like distribution from the left side of the FC to the right side. The maximum erosion depth and the mass loss rate are positive with the FC’s taper angle. When the taper is 1/5, the mass loss can reach up to 60 mg and the maximum erosion depth can reach 1.1 μm.
Journal Article
The role of CBL–CIPK signaling in plant responses to biotic and abiotic stresses
Plants have a variety of regulatory mechanisms to perceive, transduce, and respond to biotic and abiotic stress. One such mechanism is the calcium-sensing CBL–CIPK system responsible for the sensing of specific stressors, such as drought or pathogens. CBLs perceive and bind Calcium (Ca2+) in response to stress and then interact with CIPKs to form an activated complex. This leads to the phosphorylation of downstream targets, including transporters and ion channels, and modulates transcription factor levels and the consequent levels of stress-associated genes. This review describes the mechanisms underlying the response of the CBL–CIPK pathway to biotic and abiotic stresses, including regulating ion transport channels, coordinating plant hormone signal transduction, and pathways related to ROS signaling. Investigation of the function of the CBL–CIPK pathway is important for understanding plant stress tolerance and provides a promising avenue for molecular breeding.Key messageThe present review focuses primarily on the vital role played by CBL–CIPK signaling in plant responses to biotic and abiotic stress, as well as its function in plant development and growth. The complexity of the CBL–CIPK signaling axis underlines its significance in plant adaptation and survival, emphasizing the need for further exploration of this intricate signaling network system. Continued exploration of the CBL–CIPK model is likely to unveil fresh insights into the molecular mechanisms that underlie plant growth and stress responses. Additionally, it could lead to the formulation of novel strategies for crop improvement and environmental sustainability. Given the progress in transgenic technology and molecular breeding approaches, a comprehensive examination of all CBL and CIPK genes is expected to demonstrate that the CBL–CIPK axis is exceedingly advantageous for plant resistance breeding. The CBL–CIPK axis provides a framework for understanding calcium-mediated signaling in plants especially under challenging environmental conditions.
Journal Article
Strong atmospheric new particle formation in winter in urban Shanghai, China
Particle size distributions in the range of 1.34–615 nm were recorded from 25 November 2013 to 25 January 2014 in urban Shanghai, using a combination of one nano condensation nucleus counter system, one nano scanning mobility particle sizer (SMPS), and one long-SMPS. Measurements of sulfur dioxide by an SO2 analyzer with pulsed UV fluorescence technique allowed calculation of sulfuric acid proxy. In addition, concentrations of ammonia were recorded with a differential optical absorption spectroscopy. During this 62-day campaign, 13 new particle formation (NPF) events were identified with strong bursts of sub-3 nm particles and subsequent fast growth of newly formed particles. The observed nucleation rate (J1.34), formation rate of 3 nm particles (J3), and condensation sink were 112.4–271.0 cm−3 s−1, 2.3–19.2 cm−3 s−1, and 0.030–0.10 s−1, respectively. Subsequent cluster/nanoparticle growth (GR) showed a clear size dependence, with average values of GR1.35~1.39, GR1.39~1.46, GR1.46~1.70, GR1.70~2.39, GR2.39~7, and GR7~20 being 1.6±1.0, 1.4±2.2, 7.2±7.1, 9.0±11.4, 10.9±9.8, and 11.4±9.7 nm h−1, respectively. Correlation between nucleation rate (J1.34) and sulfuric acid proxy indicates that nucleation rate J1.34 was proportional to a 0.65±0.28 power of sulfuric acid proxy, indicating that the nucleation of particles can be explained by the activation theory. Correlation between nucleation rate (J1.34) and gas-phase ammonia suggests that ammonia was associated with NPF events. The calculated sulfuric acid proxy was sufficient to explain the subsequent growth of 1.34–3 nm particles, but its contribution became smaller as the particle size grew. Qualitatively, NPF events in urban Shanghai likely occur on days with low levels of aerosol surface area, meaning the sulfuric acid proxy is only a valid predictor when aerosol surface area is low.
Journal Article
Injury-related fatalities in China: an under-recognised public-health problem
The May 2008 earthquake in Wenchuan drew attention to the important but largely unrecognised public-health problem of injury-related mortality and morbidity in China. Injuries account for more than 10% of all deaths and more than 30% of all potentially productive years of life lost due to premature mortality in China. Traffic-related injuries (mainly among cyclists and pedestrians), suicide, drowning, and falls account for 79% of all injury deaths. Rural injury death rates are double those of urban rates and male rates are double those of female rates. Despite an 81% increase in the traffic-related mortality from 1987 to 2006—associated with rapid motorisation—the overall injury mortality decreased by 17%, largely due to a surprising (and unexplained) 57% reduction in the suicide rate. Low-cost prevention measures that are most likely to produce large reductions in injury deaths include enforcement of laws for drinking and driving and for seat belt and helmet use, restriction of access to the most potent pesticides, and teaching children to swim. China needs to improve monitoring of fatal and non-fatal injuries, promote intersectoral collaboration, build institutional capacities, and, most importantly, mobilise community support and political will for investment in prevention.
Journal Article
Association of Systemic Immune Inflammation Index with All-Cause, Cardiovascular Disease, and Cancer-Related Mortality in Patients with Cardiovascular Disease: A Cross-Sectional Study
Our research was designed to investigate the relationship between systemic immune inflammation (SII) index and all-cause, cardiovascular disease (CVD), and cancer-related mortality in patients with CVD.
We used the National Health and Nutrition Examination Survey data from 1999 to 2018 to conduct this study. The association between SII index and all-cause, CVD, and cancer-related mortality in patients with CVD was examined using restricted cubic splines (RCS), Cox proportional hazard models, and subgroup analysis, respectively. CVD was defined as a composite of five outcomes of CVD, including coronary heart disease (CHD), congestive heart failure (CHF), angina pectoris, myocardial infarction, and stroke. Additionally, the link between SII index and all-cause, CVD, and cancer-related mortality in patients with a composite of five outcomes of CVD was also explored.
In total, 5329 participants were included. The RCS also showed a U-curve correlation between SII index and the all-cause, CVD, and cancer-related mortality in patients with CVD. As compared with the individuals with lowest quartile of SII index, hazard ratios with 95% confidence intervals for all-cause, CVD, and cancer-related mortality across the quartiles were (1.202 (0.981, 1.474), 1.184 (0.967, 1.450), and 1.365 (1.115, 1.672)), (1.116 (0.815, 1.527), 1.017 (0.740, 1.398), and 1.220 (0.891, 1.670)), and (1.202 (0.981, 1.474), 1.184 (0.967, 1.450), and 1.365 (1.115, 1.672)), respectively, in the full-adjusted model. The SII index also had a U-shaped relationship with all-cause, CVD, and cancer-related mortality in patients with CHD, angina, and myocardial infarction. Additionally, the U-shaped relationship between SII index and all-cause, and cancer-related mortality also exists in CHF, and stroke. However, there was a positive linear correlation between SII index and CVD mortality in patients with CHF, and stroke.
In the United States general population, the correlation between SII index and all-cause, CVD, and cancer-related mortality showed a U-shaped curve in patients with CVD.
Journal Article
MicroRNA expression profiling identifies miR-328 regulates cancer stem cell-like SP cells in colorectal cancer
Background:
Side population (SP) cells and their relationship to stem cell-like properties have been insufficiently studied in colorectal cancer (CRC). MicroRNAs (miRNAs) have attracted much attention but their roles in the maintenance of SP phenotype remain unclear.
Methods:
The SPs from CRC cell lines and primary cell cultures were analysed for stem cell-like properties. MiRNA microarray analysis identified miR-328 as a potential stemness miRNA of SP phenotype. The level of miR-328 expression in clinical samples and its correlation with SP fraction were determined. Gain-of-function and loss-of-function studies were performed to examine its roles in cancer stem-like SP cells. Furthermore, bioinformatics prediction and experimental validation were used to identify miR-328 target genes.
Results:
The SP cells sorted from CRC possess cancer stem cell (CSC)-like properties, including self-renewal, differentiation, resistance to chemotherapy, invasive and strong tumour formation ability. MiR-328 expression was significantly reduced in SP cells compared with Non-SP cells (
P
<0.05). Moreover, miR-328 expression was downregulated in CRC (
n
=33,
P
<0.05) and low miR-328 expression tend to correlate with high SP fraction (
n
=15,
r
=0.6559,
P
<0.05, Pearson's correlation). Functional studies indicated that miR-328 expression affects the number of SP cells. In addition, miR-328 overexpression reversed drug resistance and inhibited cell invasion of SP cells. Furthermore, luciferase reporter assay demonstrated that miR-328 directly targets ABCG2 and MMP16 and affects the levels of mRNA and protein expression in SP cells.
Conclusion:
These findings indicate that CRC contain cancer stem-like SP cells. MiR-328 has an important role in maintaining cancer stem-like SP phenotype that may be a potential target for effective CRC therapy.
Journal Article