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"She, Wei"
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Multi-layered cement-hydrogel composite with high toughness, low thermal conductivity, and self-healing capability
The inherent quasi-brittleness of cement-based materials, due to the disorder of their hydration products and pore structures, present significant challenges for directional matrix toughening. In this work, a rigid layered skeleton of cement slurry was prepared using a simplified ice-template method, and subsequently flexible polyvinyl alcohol hydrogel was introduced into the unidirectional pores between neighboring cement platelets, resulting in the formation of a multi-layered cement-based composite. A toughness improvement of over 175 times is achieved by the implantation of such hard-soft alternatively layered microstructure. The toughening mechanism is the stretching of hydrogels at the nano-scale and deflections of micro-cracks at the interfaces, which avoid stress concentration and dissipate huge energy. Furthermore, this cement-hydrogel composite also exhibits a low thermal conductivity (around 1/10 of normal cement) and density, high specific strength and self-healing properties, which can be used in thermal insulation, seismic high-rise buildings and long-span bridges.
Despite widely used in the construction sector, Portland cement’s high brittleness and low toughness still pose challenges in some applications. Here, authors apply an ice-templating method to fabricate a cement-hydrogel composite with alternating layered microstructure resulting in significantly increased toughness.
Journal Article
Activated NK cells cause placental dysfunction and miscarriages in fetal alloimmune thrombocytopenia
Miscarriage and intrauterine growth restriction (IUGR) are devastating complications in fetal/neonatal alloimmune thrombocytopenia (FNAIT). We previously reported the mechanisms for bleeding diatheses, but it is unknown whether placental, decidual immune cells or other abnormalities at the maternal–fetal interface contribute to FNAIT. Here we show that maternal immune responses to fetal platelet antigens cause miscarriage and IUGR that are associated with vascular and immune pathologies in murine FNAIT models. Uterine natural killer (uNK) cell recruitment and survival beyond mid-gestation lead to elevated NKp46 and CD107 expression, perforin release and trophoblast apoptosis. Depletion of NK cells restores normal spiral artery remodeling and placental function, prevents miscarriage, and rescues hemorrhage in neonates. Blockade of NK activation receptors (NKp46, FcɣRIIIa) also rescues pregnancy loss. These findings shed light on uNK antibody-dependent cell-mediated cytotoxicity of invasive trophoblasts as a pathological mechanism in FNAIT, and suggest that anti-NK cell therapies may prevent immune-mediated pregnancy loss and ameliorate FNAIT.
Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is a gestational disease caused by maternal immune responses against fetal platelets. Using a FNAIT mouse model and human trophoblast cell lines, here the authors show that uterine natural killer cell-mediated trophoblast apoptosis contributes to FNAIT pathogenesis.
Journal Article
Significance of the Balance between Regulatory T (Treg) and T Helper 17 (Th17) Cells during Hepatitis B Virus Related Liver Fibrosis
Hepatitis B virus-related liver fibrosis (HBV-LF) always progresses from inflammation to fibrosis. However, the relationship between these two pathological conditions is not fully understood. Here, it is postulated that the balance between regulatory T (Treg) cells and T helper 17 (Th17) cells as an indicator of inflammation may predict fibrosis progression of HBV-LF.
The frequencies and phenotypes of peripheral Treg and Th17 cells of seventy-seven HBeAg-positive chronic hepatitis B (CHB) patients who underwent liver biopsies and thirty healthy controls were determined by flow cytometry. In the periphery of CHB patients, both Treg and Th17 frequencies were significantly increased and correlated, and a lower Treg/Th17 ratio always indicated more liver injury and fibrosis progression. To investigate exact effects of Treg and Th17 cells during HBV-LF, a series of in vitro experiments were performed using purified CD4(+), CD4(+)CD25(+), or CD4(+)CD25(-) cells from the periphery, primary human hepatic stellate cells (HSCs) isolated from healthy liver specimens, human recombinant interleukin (IL)-17 cytokine, anti-IL-17 antibody and HBcAg. In response to HBcAg, CD4(+)CD25(+) cells significantly inhibited cell proliferation and cytokine production (especially IL-17 and IL-22) by CD4(+)CD25(-) cells in cell-contact and dose-dependent manners. In addition, CD4(+) cells from CHB patients, compared to those from HC subjects, dramatically promoted proliferation and activation of human HSCs. Moreover, in a dramatically dose-dependent manner, CD4(+)CD25(+) cells from CHB patients inhibited, whereas recombinant IL-17 response promoted the proliferation and activation of HSCs. Finally, in vivo evidence about effects of Treg/Th17 balance during liver fibrosis was obtained in concanavalin A-induced mouse fibrosis models via depletion of CD25(+) or IL-17(+) cells, and it's observed that CD25 depletion promoted, whereas IL-17 depletion, alleviated liver injury and fibrosis progression.
The Treg/Th17 balance might influence fibrosis progression in HBV-LF via increase of liver injury and promotion of HSCs activation.
Journal Article
Mesenchymal stem cell-derived exosomes improve vascular remodeling by inhibiting EGFR/ErbB2 heterodimerization in hypoxic pulmonary hypertension
A key characteristic of hypoxic pulmonary hypertension (HPH) is pulmonary vascular remodeling, involving abnormal proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). Recent studies indicate that mesenchymal stem cell-derived exosomes (MSC-exo) exhibit therapeutic effects on HPH. MSC-exosomes were isolated from the conditioned medium of bone mesenchymal stem cells using ultracentrifugation, confirmed via Western blotting (WB), transmission electron microscopy (TEM), and nanoparticle tracking analyses (NTA). Platelet-derived growth factor BB (PDGFBB) induced pathological behavior in PASMCs, replicating the conditions observed in HPH. HPH rats were subjected to a low oxygen environment (10 ± 1% oxygen) for 8 h daily over 28 days. Parameters such as right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), and pulmonary vascular remodeling were evaluated. MSC-exosomes suppressed PDGFBB-induced proliferation and migration of PASMCs. Additionally, MSC-exosomes protected rats from hypoxia-induced increases in RVSP, right ventricular hypertrophy, and pulmonary vascular remodeling. The expression of epidermal growth factor receptor (EGFR) and Erb-B2 receptor tyrosine kinase 2 (ErbB2) was investigated in both HPH lung tissues and PDGFBB-induced PASMCs. Results indicated significant upregulation of EGFR/ErbB2 expression in HPH and PDGFBB-induced PASMCs, which was suppressed by MSC-exosomes. The study demonstrates that MSC-exosomes inhibit the development of HPH by suppressing excessive proliferation and migration of PASMCs through the inhibition of EGFR/ErbB2 heterodimerization.
Journal Article
Nanomedicine: A Promising Way to Manage Alzheimer’s Disease
Alzheimer’s disease (AD) is a devastating disease of the aging population characterized by the progressive and slow brain decay due to the formation of extracellular plaques in the hippocampus. AD cells encompass tangles of twisted strands of aggregated microtubule binding proteins surrounded by plaques. Delivering corresponding drugs in the brain to deal with these clinical pathologies, we face a naturally built strong, protective barrier between circulating blood and brain cells called the blood–brain barrier (BBB). Nanomedicines provide state-of-the-art alternative approaches to overcome the challenges in drug transport across the BBB. The current review presents the advances in the roles of nanomedicines in both the diagnosis and treatment of AD. We intend to provide an overview of how nanotechnology has revolutionized the approaches used to manage AD and highlight the current key bottlenecks and future perspective in this field. Furthermore, the emerging nanomedicines for managing brain diseases like AD could promote the booming growth of research and their clinical availability.
Journal Article
Synergistic Effect of Cr and Fe Elements on Stress Corrosion Fracture Toughness of Titanium Alloy
Synergistic effect of Cr and Fe elements on stress corrosion fracture toughness of titanium alloy was analyzed by phase detection, observation of the microstructure, tensile mechanical properties test and stress corrosion fracture toughness test. TC4-Cr-Fe titanium alloy and TC4 titanium alloy were composed of α phase and β phase, and no other phases were detected. The microstructure characterization showed that the primary alpha phase (α
p
) and secondary alpha phase (α
s
) can be significantly refined due to the addition of Cr and Fe elements, and the formation of α
s
can be promoted. The tensile strength and stress corrosion fracture toughness can be improved by adding Cr and Fe elements. The synergistic effect of Cr and Fe elements on stress corrosion fracture toughness was that on the one hand, the formation of small angle grain boundaries can be promoted, which had a low diffusion rate and inhibited intergranular corrosion. On the other hand, TC4-Cr-Fe titanium alloy had a large number of α
s
aggregation regions in different directions, and at the same time, it had a higher proportion of schmid factor ≤ 0.3 in pyramidal slip system. Therefore, when the crack passes through, it will be frequently changed in direction, which has obvious retardation and deflection effect on the crack extension process. And when the grains with low schmid factor were penetrated by cracks, a large number of slip systems were difficult to start, resulting in stress concentration and dislocation density increase. The increase of dislocation density can effectively weaken the driving energy of micro-crack extension and increase the energy needed for its continuous extension, thus the crack extension process was hindered.
Graphical Abstract
Journal Article
Ramie Yield Estimation Based on UAV RGB Images
Timely and accurate crop growth monitoring and yield estimation are important for field management. The traditional sampling method used for estimation of ramie yield is destructive. Thus, this study proposed a new method for estimating ramie yield based on field phenotypic data obtained from unmanned aerial vehicle (UAV) images. A UAV platform carrying RGB cameras was employed to collect ramie canopy images during the whole growth period. The vegetation indices (VIs), plant number, and plant height were extracted from UAV-based images, and then, these data were incorporated to establish yield estimation model. Among all of the UAV-based image data, we found that the structure features (plant number and plant height) could better reflect the ramie yield than the spectral features, and in structure features, the plant number was found to be the most useful index to monitor the yield, with a correlation coefficient of 0.6. By fusing multiple characteristic parameters, the yield estimation model based on the multiple linear regression was obviously more accurate than the stepwise linear regression model, with a determination coefficient of 0.66 and a relative root mean square error of 1.592 kg. Our study reveals that it is feasible to monitor crop growth based on UAV images and that the fusion of phenotypic data can improve the accuracy of yield estimations.
Journal Article
Acupuncture versus propranolol in migraine prophylaxis: an indirect treatment comparison meta-analysis
Background
Propranolol is recommended as first-line treatment for preventing migraine attacks; acupuncture has not been compared with propranolol in a head-to-head trial.
Objective
To compare acupuncture with propranolol using indirect treatment comparison meta-analysis.
Method
We searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL). Randomized controlled trials comparing acupuncture or propranolol with sham acupuncture, placebo, waiting-list control or usual care were included. We extracted information from the included trials using a standardized extraction form. The primary outcome was migraine episodes. The secondary outcomes included migraine days, migraine frequency, and adverse events.
Results
We included 19 RCTs (
n
= 3656) after screening 1078 articles. The analysis showed that acupuncture had a significant advantage over propranolol in reducing migraine episodes over a 4-week period (SMD − 0.74, 95% CI − 1.04 to − 0.44). Acupuncture also had a significant advantage over waiting-list control in decreasing migraine frequency (SMD − 1.57, 95% CI − 2.08 to − 1.06). Acupuncture caused fewer adverse events than propranolol (RR 0.82, 95% CI 0.11–5.94).
Conclusions
Acupuncture had a better effect than propranolol in reducing migraine episodes in indirect comparison. The result should be confirmed in subsequent head-to-head studies.
Registration
: PROSPERO CRD42018108585
Journal Article
The Application of Nanotechnology for the Diagnosis and Treatment of Brain Diseases and Disorders
Brain is by far the most complex organ in the body. It is involved in the regulation of cognitive, behavioral, and emotional activities. The organ is also a target for many diseases and disorders ranging from injuries to cancers and neurodegenerative diseases. Brain diseases are the main causes of disability and one of the leading causes of deaths. Several drugs that have shown potential in improving brain structure and functioning in animal models face many challenges including the delivery, specificity, and toxicity. For many years, researchers have been facing challenge of developing drugs that can cross the physical (blood–brain barrier), electrical, and chemical barriers of the brain and target the desired region with few adverse events. In recent years, nanotechnology emerged as an important technique for modifying and manipulating different objects at the molecular level to obtain desired features. The technique has proven to be useful in diagnosis as well as treatments of brain diseases and disorders by facilitating the delivery of drugs and improving their efficacy. As the subject is still hot, and new research findings are emerging, it is clear that nanotechnology could upgrade health care systems by providing easy and highly efficient diagnostic and treatment methods. In this review, we will focus on the application of nanotechnology in the diagnosis and treatment of brain diseases and disorders by illuminating the potential of nanoparticles.
Journal Article