The water retention properties of a natural loess from northern France were investigated on intact block samples that were excavated along a high-speed train line (TGV) that experienced stability ...problems during heavy rain episodes. Suction measurements were made by using the filter paper method and an in-house constructed high-capacity tensiometer (HCT) so as to determine the water retention curve of the loess. The results showed that an alternative approach using a previously wetted filter paper could fruitfully be used with suction values reasonably compatible with the HCT measurements. The water retention curve obtained exhibited a peculiar form, with no hysteresis observed around the natural water content (14·4%) and two hysteresis loops on both the wet and dry sides of the curve. It is hypothesised that this zone with no hysteresis corresponds to the natural variations of the water content under seasonal changes, providing a range of natural suction between 20 and 80 kPa, and it is suggested that this should be checked by in situ measurements. The loess microstructure was investigated by using scanning electron microscopy and mercury intrusion porosimetry. It appeared that the clay fraction (16%) was not uniformly distributed, with some areas composed of clean grains and a well-graded corresponding intergrain pore population. Conversely, the clay aggregations define a smaller-sized porosity. The calculation of a water retention curve derived from the pore size distribution curve showed that water retention is governed by capillarity in the largest pores between clean grains, whereas clay adsorption becomes dominant in the smallest pores, a zone where the microstructure is sensitive to change in water content.
The HGF/MET signaling pathway is critical in mediating a wide range of normal physiological functions including embryological development, wound healing, and tissue regeneration. Aberrant activation ...of the pathway has frequently been found in human cancers via protein overexpression, mutation, gene amplification, and also paracrine or autocrine up-regulation. In addition, the activation of HGF/MET signaling confers resistance to the effects of cancer treatments. Therefore, inhibition of the HGF/MET signaling pathway has great potential for therapeutic intervention in cancer. Currently, there are three approaches toward modulating HGF/MET signaling in human clinical studies of cancer: anti-HGF monoclonal antibodies, MET monoclonal antibodies, and small molecule MET inhibitors. Preliminary clinical benefit from inhibition of HGF or MET has been reported. This Perspective will provide an overview of the HGF/MET signaling pathway in cancer and then will review the development of small molecule MET inhibitors and their progress in clinical applications.
This paper is concerned with the dynamics of large bubbles subject to various strengths of buoyancy effects, which are associated with applications for underwater explosion. The bubble is produced by ...electric discharge in a low-pressure tank to enhance the buoyancy effects. Experiments are carried out for a bubble in an infinite field, below a free surface and above a rigid boundary. The effects of buoyancy are reflected by the dimensionless parameter
${\it\delta}=\sqrt{{\it\rho}gR_{m}/(p_{amb}-p_{v})}$
, where
$R_{m}$
,
$p_{amb}$
,
$p_{v}$
,
${\it\rho}$
and
$g$
are the maximum bubble radius, ambient pressure, saturated vapour pressure, density of water and the acceleration of gravity respectively. A systematic study of buoyancy effects is carried out for a wide range of
${\it\delta}$
from 0.034 to 0.95. A series of new phenomena and new features is observed. The bubbles recorded are transparent, and thus we are able to display and study the jet formation, development and impact on the opposite bubble surface as well as the subsequent collapsing and rebounding of the ring bubble. Qualitative analyses are carried out for the bubble migration, jet velocity and jet initiation time, etc. for different values of
${\it\delta}$
. When a bubble oscillates below a free surface or above a rigid boundary, the Bjerknes force due to the free surface (or rigid boundary) and the buoyancy are in opposite directions. Three situations are studied for each of the two configurations: (i) the Bjerknes force being dominant, (ii) the buoyancy force being dominant and (iii) the two forces being approximately balanced. For case (iii), we further consider two subcases, where both the balanced Bjerknes and buoyancy forces are weak or strong. When the Bjerknes and buoyancy forces are approximately balanced over the pulsation, some representative bubble behaviours are observed: the bubble near free surface is found to split into two parts jetting away from each other for small
${\it\delta}$
, or involutes from both top and bottom for large
${\it\delta}$
. A bubble above a rigid wall is found to be subject to contraction from the lateral part leading to bubble splitting. New criteria are established based on experimental results for neutral collapses where there is no dominant jetting along one direction, which correlate well with the criteria of Blake et al. (J. Fluid Mech., vol. 170, 1986, pp. 479–497; J. Fluid Mech., vol. 181, 1987, pp. 197–212) but agree better with the experimental and computational results.
Gaomiaozi (GMZ) bentonite has been recognized as the first choice for using as buffer/backfill materials in deep geological repository for the disposal of high-level nuclear waste (HLW) in China. ...Groundwater in Beishan area, which has been considered as a potential site for the construction of Chinese deep geological repository, may reach a high pH value because of its chemical background and possible cement degradation during the operation of the repository. Meanwhile, temperature may increase with decay heat released from the waste in the canister. Investigation of pH value of alkaline-solutions and temperature effects on the behavior of compacted GMZ01 bentonite is of great importance for the Chinese deep geological repository program. For this purpose, a series of swelling pressure and hydraulic conductivity tests with various pHs of NaOH solutions were conducted at different temperatures. The X-ray diffraction (XRD) exploration was performed on the GMZ01 bentonite specimens before and after experiencing the swelling pressure and hydraulic conductivity tests, in order to find out the influences of temperature and pHs on the mineralogy of GMZ01 bentonite. Results show that the swelling pressure of GMZ01 bentonite decreases as the pH value of NaOH solutions increases, while the decreasing rate significantly depends on temperature. The swelling pressure evolution curve was "double-peak" structured, which faded with the increases of pH and temperature. The hydraulic conductivity of GMZ01 bentonite increases with the increase of the pH value of NaOH solutions and the rise of temperature. All these observations were consistent with the XRD test results: the dissolution of montmorillonite in GMZ01 bentonite increases with the pH increases. This process was accelerated by the temperature rise.
This systematic review and meta-analysis estimated the global, regional prevalence, and risk factors of osteoporosis. Prevalence varied greatly according to countries (from 4.1% in Netherlands to ...52.0% in Turkey) and continents (from 8.0% in Oceania to 26.9% in Africa). Osteoporosis is a common metabolic bone disorder in the elderly, usually resulting in bone pain and an increased risk of fragility fracture, but few summarized studies have guided global strategies for the disease. Therefore, we pooled the epidemiologic data to estimate the global, regional prevalence, and potential risk factors of osteoporosis. We conducted a comprehensive literature search through PubMed, EMBASE, Web of Science, and Scopus, to identify population-based studies that reported the prevalence of osteoporosis based on the World Health Organization (WHO) criteria. Meta-regression and subgroup analyses were used to explore the sources of heterogeneity. The study was registered in the PROSPERO database (CRD42021285555). Of the 57,933 citations evaluated, 108 individual studies containing 343,704 subjects were included. The global prevalence of osteoporosis and osteopenia was 19.7% (95%CI, 18.0%–21.4%) and 40.4% (95%CI, 36.9%–43.8%). Prevalence varied greatly according to countries (from 4.1% in Netherlands to 52.0% in Turkey) and continents (from Oceania 8.0% to 26.9% in Africa). The prevalence was higher in developing countries (22.1%, 95%CI, 20.1%–24.1%) than in developed countries (14.5%, 95%CI, 11.5%–17.7%). Our study indicates a considerable prevalence of osteoporosis among the general population based on WHO criteria, and the prevalence varies substantially between countries and regions. Future studies with robust evidence are required to explore risk factors to provide effective preventive strategies for the disease.
Multicolor carbon dots (CDs) have been developed recently and demonstrate great potential in bio-imaging, sensing, and LEDs. However, the fluorescence mechanism of their tunable colors is still under ...debate, and efficient separation methods are still challenging. Herein, we synthesized multicolor polymeric CDs through solvothermal treatment of citric acid and urea in formamide. Automated reversed-phase column separation was used to achieve fractions with distinct colors, including blue, cyan, green, yellow, orange and red. This work explores the physicochemical properties and fluorescence origins of the red, green, and blue fractions in depth with combined experimental and computational methods. Three dominant fluorescence mechanism hypotheses were evaluated by comparing time-dependent density functional theory and molecular dynamics calculation results to measured characteristics. We find that blue fluorescence likely comes from embedded small molecules trapped in carbonaceous cages, while pyrene analogs are the most likely origin for emission at other wavelengths, especially in the red. Also important, upon interaction with live cells, different CD color fractions are trafficked to different sub-cellular locations. Super-resolution imaging shows that the blue CDs were found in a variety of organelles, such as mitochondria and lysosomes, while the red CDs were primarily localized in lysosomes. These findings significantly advance our understanding of the photoluminescence mechanism of multicolor CDs and help to guide future design and applications of these promising nanomaterials.
Understanding the origin and sensitivity of carbon dot emission will improve their utility in various applications.
Blood-circulating microRNAs (miRNAs) have been reported to be used as potential biomarkers in various cancers. MiR-101 has been found to act as a tumor suppressor in many tumor types, but little is ...known for osteosarcoma. The purpose of this study was to investigate miR-101 expression in osteosarcoma patients and assess its correlation with clinical features and prognosis. Serum samples from 152 osteosarcoma patients and 70 healthy controls were detected using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The data showed that miR-101 expression levels were remarkably underexpressed in serum samples from osteosarcoma patients compared to controls, and the post-treatment serum miR-101 expression was significantly higher than that in the pre-treatment expression. Low serum miR-101 expression was positively associated with advanced clinical stage and distant metastasis. Receiver operating characteristic (ROC) curve analysis showed that serum miR-101 could serve as a useful marker for osteosarcoma diagnosis, with a high sensitivity and specificity. Moreover, patients with high miR-101 expression had longer overall survival and recurrence free survival than those with low miR-101 expression. In addition, both univariate and multivariate analyses showed that serum miR-101 downregulation was associated with shorter overall survival and recurrence free survival. Our present results implicated serum miR-101 might be a useful biomarker for the clinical diagnosis and prognosis of osteosarcoma.
The plastic deformation behavior and the effects of the impact time on the LY2 aluminum (Al) alloy during multiple laser shock processing (LSP) impacts were investigated. The residual stress in the ...near-surface region was determined by X-ray diffraction. In addition, the micro-structural features of the hardening layer were characterized by scanning electron microscopy, optical microscopy and transmission electron microscopy. It was found that the micro-structure was obviously refined due to the ultra-high plastic strain induced by multiple LSP impacts. The minimum grain size in the top surface after multiple LSP impacts was about 100–200
nm. The grain refinement process after multiple LSP impacts can be described as follows: (i) the formation and development of dislocation lines in original grains; (ii) dislocation tangles (DTs) and the formation of dense dislocation walls (DDWs); (iii) transformation of DTs and DDWs into subgrain boundaries; and (iv) evolution of the continuous dynamic recrystallization in subgrain boundaries to refined grain boundaries.
Background
At present, the severity of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has been a focal point.
Methods
To assess the factors associated with ...severity and prognosis of patients infected with SARS‐CoV‐2, we retrospectively investigated the clinical, imaging and laboratory characteristics of confirmed 280 cases of novel coronavirus disease (COVID‐19) from 20 January to 20 February 2020.
Results
The median age of patients in the mild group was 37.55 years, whilst that in the severe group was 63.04 years. The proportion of patients aged over 65 years in the severe group was significantly higher than that of the mild group (59.04% vs. 10.15%, P < 0.05). 85.54% of severe patients had diabetes or cardiovascular diseases, which was significantly higher than that of the mild group (51.81% vs. 7.11%, P = 0.025; 33.73% vs. 3.05%, P = 0.042). Patients in the mild group experienced earlier initiation of antiviral treatment (1.19 ± 0.45 vs. 2.65 ± 1.06 days in the severe group, P < 0.001). Our study showed that comorbidity, time from illness onset to antiviral treatment and age >=65 were three major risk factors for COVID‐19 progression, whilst comorbidity and time from illness onset to antiviral treatment were two major risk factors for COVID‐19 recovery.
Conclusions
The elderly and patients with underlying diseases are more likely to experience a severe progression of COVID‐19. It is recommended that timely antiviral treatment should be initiated to slow the disease progression and improve the prognosis.
•Thermally-stable high-performance nanocrystalline MMP Nd-Ce-Fe-B magnet is fabricated by grain boundary engineering.•Hcj and thermal stability are obviously improved with simultaneously enhanced ...(BH)max.•Microstructure evolution is revealed, and the Dy diffusion model is proposed.•The underlying mechanisms for enhanced magnetic properties and thermal stability are systematically analyzed.
Low coercivity and poor thermal stability are still the main challenges for practical application of low-cost Nd-Ce-Fe-B magnet. To solve these challenging problems, a strategy to simultaneously improve the coercivity and thermal stability of Nd-Ce-Fe-B magnet through combining the nanocrystalline multi-main-phase (MMP) structure and grain boundary engineering is demonstrated. In this study, nanocrystalline MMP Nd-Ce-Fe-B magnet was grain boundary engineered by co-adding DyF3 and Cu powders. The results show that the intrinsic coercivity Hcj is significantly improved, and meanwhile optimum maximum energy product (BH)max is achieved at 2 wt% DyF3-Cu. Moreover, the superior reversible temperature coefficients of Hcj (β) and Br (α) are both achieved, implying the improved thermal stability for the DyF3-Cu added magnet. Microstructural and compositional characterizations indicate that the modified RE-rich phase, the inhibited abnormal grain growth near the flake boundary, and the diffused Dy towards main phase grains are the main reasons for simultaneously enhanced magnetic properties and thermal stability. Thus, combining the nanocrystalline MMP structure and grain boundary engineering will be a promising approach for preparing thermally-stable high-performance Nd-Ce-Fe-B magnet.
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