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Bone health related skeletal disorders are commonly diagnosed by X-ray imaging, but the radiation limits its use. Light excitation and optical imaging through the near-infrared-II window (NIR-II, 1000–1700 nm) can penetrate deep tissues without radiation risk, but the targeting of contrast agent is non-specific. Here, we report that lanthanide-doped nanocrystals can be passively transported by endothelial cells and macrophages from the blood vessels into bone marrow microenvironment. We found that this bone targeting scheme can be effective for longer than two months. We therefore developed an intravital 3D and high-resolution planar imaging instrumentation for bone disease diagnosis. We demonstrated the regular monitoring of 1 mm bone defects for 11 days in NIR-II window, with spatial resolution similar to X-ray imaging result, but more flexible use in prognosis. Moreover, the passive targeting can be used to reveal the early onset inflammation at the joints as the synovitis in the early stage of rheumatoid arthritis. Furthermore, the proposed method is comparable to micro computed tomography (µCT) in recognizing symptoms of osteoarthritis, including the mild hyperostosis in femur which is ~ 100 µm thicker than normal, and the growth of millimeter-scale osteophyte in the knee joint, which further proves the power and universality of our approach.

Biomass can be torrefied to improve the fuel quality prior to its utilization. In addition, a large number of soluble alkali metals can be removed by water washing, to solve slagging and other ash-related problems. In this study, computer-controlled scanning electron microscopy (CCSEM) was used to analyze the mineral composition and elemental distribution of straw, torrefied straw char, and torrefied-water washed straw char. The mineral transformation behavior and the distribution of main elements, when these biomass species were individually co-combusted with coal, were also studied in detail. The comparison of the mineral composition of bulk ash obtained from torrefied straw combustion and straw combustion revealed that the quartz phase decreased and the aluminosilicates of K-, Na-, and Ca–Fe–K increased in the former compared to that in the latter. After the torrefied straw was washed with water, the quartz and Si-Rich phases increased. K aluminosilicate decreased and the quartz phase increased when the torrefied sample was co-combusted with coal at both mixing ratios of 1:1 and 1:4 compared to straw/coal co-combustion. When the torrefied-water washing sample and coal were co-combusted at a 1:1 ratio, the quartz phase decreased, and the Si-Rich and mullite phases increased. When the straw/torrefied char/torrefied-washed char was co-fired with coal at the 1:4 ratio, the amount of K aluminosilicate was less compared to that observed at the 1:1 ratio. It can be concluded that both torrefaction and torrefaction-washing can reduce the content of low-melting-point aluminosilicates in the mineral composition of the studied biomass after co-combustion, which can be beneficial to alleviate the ash slagging problem.

Background: Mechanical loading and alendronate (ALN) can be used as noninvasive physical therapy methods for osteoarthritis (OA). However, the timing and efficacy for treatments are unknown. Purpose: To determine whether the timing of mechanical loading and ALN influences the pathobiological changes of OA. Study Design: Controlled laboratory study. Methods: Mice with OA induced by anterior cruciate ligament transection were subjected to early (1-3 weeks) or late (5-7 weeks) axial compressive dynamic load or intraperitoneal injection of ALN. Changes in gait were analyzed using gait analysis system, pathobiological changes in subchondral bone, cartilage, osteophyte, and synovitis were assessed using micro–computed tomography, tartrate-resistant acid phosphatase staining, pathologic section staining, and immunohistochemistry at 1, 2, 4, and 8 weeks. Results: At 1, 2, and 4 weeks, the OA limb had lower mean footprint pressure intensity, lower bone volume per tissue volume (BV/TV) in the subchondral bone, and more osteoclasts. At 4 weeks, the early loading, ALN, and load + ALN treatments induced less cartilage destruction, with a corresponding reduction in Osteoarthritis Research Society International score and increased hyaline cartilage thickness. The treatments also resulted in fewer osteoclasts and higher BV/TV and bone mineral density of subchondral bone and suppressed inflammation and interleukin 1β– and tumor necrosis factor α-positive cells in synovium. At 8 weeks, early loading or load + ALN improved the mean footprint pressure intensity and knee flexion. At 8 weeks, early load + ALN had a synergistic effect on protecting hyaline cartilage and proteoglycans. Footprint pressure intensity and cartilage destruction were worse in late loading limbs, and no differences in BV/TV, bone mineral density, osteophyte formation, and synovium inflammation were found between the late load, ALN, and load + ALN groups and the anterior cruciate ligament transection group. Conclusion: Dynamic axial mechanical loading or ALN in the early stages of knee trauma protected against OA by suppressing subchondral bone remodeling. However, late loading promoted cartilage degeneration in advanced OA, indicating that reduced loading should be performed in the late stages of OA to avoid the acceleration of OA. Clinical Relevance: Early low-level functional exercise or antiosteoporotic drugs could clearly slow or prevent the progression of early OA. For patients with mild to severe OA, loading reduction via brace protection or maintenance of joint stability via early ligament reconstruction surgery may ameliorate OA exacerbation.

To understand the behavior of pyrite (a key slag-inducing coal mineral) in oxyfuel combustion (O2/CO2 combustion), our previous work firstly investigated the effects of pure CO2 on fixed bed reactors and at low temperatures (

The understanding of the pyrolysis behavior of petroleum coke (PC), a by-product of oil refining, is very critical to its energy utilization. Different from most previous work, this investigation particularly focused on PC pyrolysis at high temperatures > 1273 K. The CO2 gasification reactivity of in-situ char, rather than quenched char, was evaluated and correlated to PC pyrolysis behavior at different temperatures. A Chinese PC with sizes below 100 μm was tested on a high-temperature thermogravimetric analyser (TGA). Three sets of tests were carried out for different purposes. The first set was to simultaneously obtain sample mass loss and gas evolution data during pyrolysis through thermogravimetry-mass spectrometry (TG-MS). The second set aimed to collect char samples for subsequent analyses by scanning electron microscopy (SEM) and Raman spectrometry. The third set was to evaluate in-situ char-CO2 gasification reactivity through the TGA. The results showed that, in addition to the commonly-observed primary pyrolysis stage at low temperatures, there was a secondary PC pyrolysis stage at high temperatures > 1300 K. In this process, the gases such as HCN, CO2 and SO2 were significantly released. The observed changes of char morphology suggested a four-staged thermoplastic transformation of the PC during pyrolysis, which has little been discussed previously. At different stages, i.e. softening, plasticizing, resolidification and graphitization, the rate of carbon ordering was different. The in-situ char-CO2 gasification reactivity was found to first increase, then decrease and finally increase again with increasing temperature. Such changes coincided with the thermoplastic state of the pyrolyzed char, but not with the changes of char surface area or carbon ordering. The obtained knowledge is new and highlights the potentially important roles of char thermoplastic state in determining its reactivity towards CO2.

Bone fracture healing is a complex process involving a cascade of cellular and molecular events that are orchestrated by a variety of factors, including neuropeptides and their receptors. However, the roles of neuropeptides and their receptors in the fracture healing process are controversial. We monitored the expression and distribution of the neuropeptides, substance P (SP) and neuropeptide Y (NPY) and their receptors, neurokinin 1 receptor (NK1) and neuropeptide Y1 receptor (NPY1R), in rats undergoing fracture healing. Total RNA was extracted using Fe3O4 and was retrieved into DNA using the MagBeads Total RNA Extraction Kit. The expression levels of SP, NK1, and NPY at each time point in the healing bone tissue were found to be higher than the levels in normal bone tissue. Their location and expression levels correlated with the healing process. In the callus formation stage, the expression levels of SP, NK1, and NPY were found to be increased in the matrix of the cartilage, in chondrocytes, and in the subperiosteal region. At the bone remodeling stage, they were located in the periosteum, new bone tissue, and perivascular regions, and their expression levels gradually reduced. Therefore, we conclude that SP was involved in callus formation and bone resorption at different physiological concentrations. At some concentrations, SP positively regulated new bone formation via NK1. At other concentrations, the SP-NK1 interaction promoted bone resorption. Very low expression levels of NPY1R were observed at the early healing stage, but they increased at the middle stage and then decreased at the late stage. This indicated that NPY was involved in bone formation through NPY1R-unrelated mechanisms. NPY1R was more involved at the later stage of bone remodeling, according to its expression levels. NPY1R contributed to callus formation and remodeling.

Managing the risk of ash deposition is still a priority for oxy-fuel combustion of biomass–coal blends. This is especially a concern when high inlet O2 concentrations are adopted to reduce the amou...

OBJECTIVE: To investigate effectiveness of picture archiving and communication systems (PACS) in lateral wedge osteotomy for cubitus varus deformity in teenagers. METHODS: A clinical data of 16 teenagers with cubitus varus deformity between July 2014 and July 2016 was retrospectively analyzed. All patients were treated with lateral wedge osteotomy and fixed with plate. Before operation, the osteotomy design (the osteotomy angle and length) was done in the PACS, including the carrying angle of healthy limb and the varus angle of affected side. There were 10 males and 6 females, with an average age of 11.4 years (range, 10-17 years). The disease duration ranged from 2 to 10 years (mean, 5.6 years). The preoperative X-ray film showed that the supracondylar fractures of the humerus had all healed, and 9 cases had internal rotation deformity; the varus angle of the affected side was 19.5°-33.5°. After operation, the fracture healing and cubitus varus deformity correction were observed by X-ray films, the elbow function was evaluated by Mayo scoring, and the elbow range of motion was detected. RESULTS: There was no significant difference between the actual intraoperative osteotomy angle and length and the preoperative design (P>0.05). The hospital stay was 2-8 days, with an average of 4.5 days. No complication such as incision infection or ulnar nerve injury occurred. All 16 cases were followed up 12-18 months, with an average of 14 months. X-ray films showed that the osteotomy healed at 2-7 months after operation, with an average of 2.5 months. The internal fixators were removed within 8-14 months after operation (mean, 12.0 months). X-ray films measurement showed that the carrying angle of the affected side recovered to (10.3±2.0)° at 1 day after operation, which was not significantly different from that of the healthy side [(10.6±1.5)°] before operation (t=0.480, P=0.637). The carrying angle of the affected side was (9.8±2.6)° at 1 year after operation, which was not significantly different from that of the healthy side [(10.4±1.6)°] at the same time point (t=0.789, P=0.438). At 1 year after operation, the ranges of flexion and extension of affected side were (131.6±8.4)° and (6.4±2.6)°, respectively; and the ranges of flexion and extension of healthy side were (134.2±6.3)° and (5.9±2.2)°, respectively. There was no significant difference between the healthy and affected sides (t=1.143, P=0.262; t=0.587, P=0.561). The elbow joint function at 1 year after operation evaluated by Mayo scoring standard rated as excellent in 9 cases, good in 6 cases, and fair in 1 case, and the excellent and good rate was 93.7%. CONCLUSION: Before lateral wedge osteotomy, the PACS is used to design the osteotomy angle and length, which can guide the operation and make the osteotomy more accurate and simple.

Utilization of biomass when combined with carbon capture and sequestration (CCS) is one feasible solution for “bioenergy with carbon capture and storage” (BECCS), which can reduce the CO2 emissions in the atmosphere. Rice husk is a unique biomass resource because its ash content is typically higher than 15% and more than 88% of this mineral matter is composed of silica. Ash partitioning and deposition mechanisms in rice husk combustion are still under investigation and will be the focus of this paper. Two different rice husk resources were tested in this work: one is from China, and another is from the United States, which are abbreviated as RH_CN and RH_US, respectively. The experimental work was performed in a 100 kW down-fired oxy-fuel combustor (OFC), and both fuels were co-fired with natural gas to achieve combustion conditions that are comparable to coal combustion. Two conditions were tested: (1) air combustion and (2) oxy-combustion with 70% O2 and 30% CO2 in oxidant gas (denoted as OXY70). Result...

Some silicon-rich mineral additives are known to be capable of capturing volatile elements evolved during combustion and, thus, may be used to mitigate ash-related problems (e.g., particulate matte...

In addition to sodium (Na), calcium (Ca) and magnesium (Mg) are also abundant in Zhundong coals and play important roles in ash deposition. This work investigated the occurrence of Ca and Mg in the...

Interactions between pyrite and silicates are very critical to ash slagging in coal-fired boilers. However, no work has been reported regarding the impacts on such interactions of CO2, the dominant component in the oxy–fuel combustion gas. This was investigated in the present work by using mixtures of pyrite and kaolinite, a prevailing silicate mineral in coal. Furthermore, the sintering strength of the generated products was also evaluated. The pyrite–kaolinite mixtures were treated on a fixed bed reactor in both N2 and CO2 for comparison. The treating temperature was 1050, 1150 and 1250 °C while the reaction time was 3, 6 and 12 min, respectively. The solid products were characterized by techniques such as X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Sintering tests of these products were carried out as well. It was found that some interactions between pyrite and kaolinite took place in the N2 atmosphere. This was evidenced by the formation of iron aluminosilicate and attributed to the effects of water vapor released from kaolinite dehydroxylation. Nevertheless, pyrite–kaolinite interactions in N2 were limited and had insignificant effects on product sintering strength development. In CO2, pyrite–kaolinite interactions were significantly enhanced, compared with those in N2. Although the kaolinite-derived water vapor had some effects, CO2 was found to play a dominant role. Enhanced pyrite–kaolinite interactions resulted in an increase of eutectic phases. Consequently, the product sintering strength development was greatly elevated. It was further found that, under the conditions investigated, the interactions between pyrite and kaolinite were actually through reactions between FeO, rather than other intermediates, and aluminosilicate. This new finding enabled us to develop the mechanisms for pyrite–kaolinite interactions in N2 and CO2.

Torrefaction is a competitive biomass pretreatment technology. However, its impacts on particulate matter (PM) formation during biomass combustion and co-combustion with coal have little been investigated. This work provides new data on the formation of PM10 (particulate matter with aerodynamic diameters less than or equal to 10 µm) from combustion of raw (RH), torrefied rice husk (TRH) and their blends with a lignite (SZ). All combustion experiments were carried out on a drop-tube furnace at 1300 °C and in air. The combustion-generated PM10 was collected by a Dekati low pressure impactor and classified into 14 size fractions for further quantification and characterization. The results indicate that, compared with the RH, the TRH-derived PM10+ (particle size above 10 µm) contains more alkalis, leading to a decrease in the production of PM1 (particle size below 1 µm). During co-combustion, fuel interactions promote the transformation of alkali chlorides to aluminosilicates. A considerable amount of water-soluble Ca and P in PM1 transforms to PM1–10 (particle size between 1–10 µm). As a result, the production of PM1 (on an ash basis) decreases while that of PM1–10 increases. Co-combustion of coal with torrefied rice husk is found to generate less PM1 but more PM1–10 than that with raw rice husk.

Carbon-based catalysts have the advantages of biological cleaning, eco-friendly and cost-effective in water treatment. While, nitrogen doped biochar promotes the development of non-radical peroxymonosulfate (PMS) activation in environmental remediation. Thus, three-dimensional sponge-like porous Fe and N co-doped biochar (Fe/CN-30) with high catalytic activity for PMS activation was synthesized. In a wide pH range (1-11), the Fe/CN-30 catalyst can efficiently degrade tetracycline (TC) with a small amount of PMS. The non-radical pathways are prominent in the TC decomposition process according to the quenching experiments, electron paramagnetic resonance (EPR) and gas chromatograph-mass spectrometer (GC-MS) analysis, in which the contribution of high-valent iron-oxo species (Fe(IV) = O) was dominant. X-ray photoelectron spectroscopy and reaction kinetic experiments confirmed that the coordination sites of Fe and N in the Fe/CN-30 are the reactive centers for TC degradation. Moreover, the successive addition of low concentration PMS into the system was confirmed to favor the PMS utilization, and the high selectivity of the Fe/CN-30 was confirmed by the analysis of pollutant structure. Furthermore, by-products of TC degradation in the Fe/CN-30/PMS system and the possible TC degradation pathways were proposed via liquid chromatography-mass spectrometry (LC-MS). Therefore, this study dedicates to providing new insights into the non-radical pathway-catalyzed AOPs.

Chloroquine phosphate (CQP) has played a role in the remission of COVID-19, but its large use will undoubtedly pollute the water. Herein, we have designed biomass carbon-based catalysts with anchoring sites for single cobalt atoms in a defined Co-N3 coordination structure (SA Co-N-C(30)). A peroxymonosulfate (PMS) activation system employing the SA Co-N-C(30) as a high-efficiency catalyst was demonstrated, which can efficiently degrade CQP in a wide pH range (3–11). The electron-transfer was proposed as the dominant non-radical pathway for CQP degradation in SA Co-N-C(30)/PMS system by electrochemical studies and quenching experiments, and the generated singlet oxygen (1O2) played a negligible role. The density functional theory (DFT) calculations and experimental results showed that Co-N3 site served as the main active site for PMS activation. In addition, SA Co-N-C(30)/PMS system had excellent efficiencies in oxidative degradation of various organic pollutants. This work opens up a new avenue to efficient degradation of organic pollutants.

In this study, novel core-shell catalyst with a new ternary heterostructure was synthesized (Fe

A Fenton-like catalyst was prepared based on isolated Fe single-atom and Fe clusters anchored onto a g-C3N4 framework. It exhibited high activity and stability in the heterogeneous activation of peroxymonosulfate (PMS) for tetracycline (TC) degradation. Both experimental and density functional theory calculation results demonstrated that the unique N-coordinated single Fe atom (Fe–N4) served as active sites with optimal binding energy for PMS activation. The experimental analysis indicated that the single Fe atoms displayed superior catalytic activity to Fe clusters. Furthermore, both high-valent iron-oxo species and single oxygen-dominated nonradical processes caused TC degradation. Among them, single Fe atoms anchored onto Fe-g-C3N4 served as Fe–N4 reactive sites can directly activate PMS to produce high-valent iron-oxo species, which was the key active nonradical species causing TC degradation.

Limited data from fluidized bed combustion tests have shown that rice husk, a silicon-rich residual biomass, has the potential to be cofired with coal while not inducing unacceptable ash-related problems. However, there is great concern regarding the behavior of rice husk ash under pulverized fuel combustion conditions, where the temperatures are much higher and expected to facilitate fuel interactions. This work, to the authors’ knowledge, is the first to investigate both ash formation and fouling behavior in rice husk firing and its cofiring with coal at a high temperature relevant to pulverized fuel combustion. A Chinese rice husk and a high alkali Xinjiang coal were selected. Combustion tests of individual fuels and their blends (with the share of rice husk being 10% and 20%, respectively) were performed at 1573 K on a laboratory drop tube furnace. Both bulk ash and fouling deposit samples were collected in each test. Techniques including X-ray diffraction (XRD), scanning electron microscopy with ener...

Knowledge is limited on the thermal behavior of sulfur during petroleum coke (PC) pyrolysis, a critical topic for its any thermal utilization processes. In this work, temperature-resolved evolution and speciation of sulfur in both gas and solid phases during pyrolysis of a high-sulfur petroleum coke were investigated, with simultaneous thermogravimetric and mass spectrometric analysis (TG-MS) and X-ray photoelectron spectroscopic analysis (XPS). The results show that the original PC contains dominantly thiophene and sulfoxide, while mercaptan, sulfate and sulfone are only present in minor amounts. The desulfurization ratio generally increases with increasing temperature or decreasing heating rate. Two slow desulfurization stages (Stage I (

While co-firing Si-rich biomass showed the potential for mitigating ash-related issues in low-rank coal combustion, the underlying mechanisms need further investigation. This work aims to examine the impacts of co-firing rice husk and its torrefied product with a high-Na/Ca/Cl low-rank coal on PM10 (particle size below 10 μm) emission and elemental partitioning. Combustion tests were performed on a drop tube furnace (DTF) at 1300 °C. The bulk ashes and PM10 were collected by fiberglass filters and Dekati low pressure impactor respectively. The ash samples were carefully characterized by X-ray diffraction (XRD), scanning electron microscope equipped with energy dispersive spectrometer (SEM-EDS), ion chromatography (IC) and inductively coupled plasma mass spectrometry (ICP-MS). It is found that co-firing raw or torrefied rice husk reduces emissions of PM1 (particle size below 1 μm) together with the Na and Cl in it, mainly due to the capture of Na by coarse Si-rich particles from rice husk. The emissions of PM1-10 (particle size between 1 and 10 μm) are elevated after co-firing. This is because the formation of Ca-silicates is facilitated instead of K-silicates, thus weaken the agglomeration between the coarse particulates with melting surface from rice husk. Compared to raw rice husk, its torrefied product leads to a lower reduction ratio regarding PM1 from co-firing. Combined the results in this and previous investigations, for raw/torrefied rice husk and Xinjiang low-rank coals, the PM1 yields from both of the individual fuels and the blends almost linearly correlated with the mole ratio of (Na + K + Cl + 2S)/(Si + Al) in the ash.

BACKGROUND To examine the effects of the addition of autologous platelet-rich plasma (PRP) into bilayer poly(lactide-co-glycolide) (PLGA) scaffolds on the reconstruction of osteochondral defects in a rabbit model. MATERIAL AND METHODS Porous PLGA scaffolds were prepared in a bilayered manner to reflect the structure of chondral and subchondral bone. Bone defects, measuring 4 mm in diameter and 4 mm in thickness, were created in both knee joints in 18 healthy New Zealand white rabbits, aged between 120-180 days old. Rabbits were randomly divided into three groups: rabbits with bone defects implanted with bilayer PLGA scaffolds (PLGA group) (N=6); or with bilayer PLGA and autologous PRP (PLGA/PRP group) (N=6); and the untreated group (control group) (N=6). The gross morphology, histology, and immunohistochemistry for the expression of collagen type II and aggrecan were observed at 12 weeks after surgery and compared using a scoring system. Micro-computed tomography (CT) imaging and relative expression of specific genes were also assessed. RESULTS The platelet concentrations in the PRP samples were found to be 4.9 times greater than that of whole blood samples. The total score on gross appearance and histology was greatest in the PLGA/PRP group, as was the expression of collagen II and aggrecan of the neo-tissue. Micro-CT imaging showed that more subchondral bone was formed in the PLGA/PRP group. CONCLUSIONS Bilayer PLGA scaffolds loaded with autologous PRP improve the reconstruction of osteochondral defects in the rabbit model.

Objective To investigate the optimal posterior screw placement and the geometry of safe zones for screw insertion in the talar neck. Methods Computed tomography data for 15 normal feet were imported into Mimics 10.01 software for 3-dimensional reconstruction; 4.0-mm-diameter screws were simulated from the lateral tubercle of the posterior process of the talus to the talar head. The range of screw paths trajectories and screw lengths at nine locations that did not breach the cortex of the talus were evaluated. In addition, the farthest (point a) and nearest point (point b) of the safe zone to the subtalar joint at each location, the anteversion angle (angle A), which is parallel to the sagittal plane, and the horizontal angle (angle B), which is perpendicular to the sagittal plane, were measured. Results The safe zone was mainly between the 30% location and the 60% location; the width of each safe zone was 13.6° ± 1.4°; the maximum height of each safe zone was 7.8° ± 1.2°. The height of the safe zone was lowest at the 30% location (4.5°) and highest at the 50% location (7.3°). The mixed safe zone of all tali was between the 50% location and the 60% location. When a screw was inserted at point a, the safe entry distance (screw length) ranged from 48.8 to 49.5 mm, and when inserted to point b, the distance ranged from 48.2 to 48.9 mm. And inserting a 48.7 mm screw, 5.6° laterally and 7.4° superiorly, from the lateral tubercle of the posterior process of the talus towards the talar head is safest. Conclusion The safe zone of posterior screw fixation have been defined applying to most talus, assuming the fractures are well reduced, this may strengthen the stability, shorten the operation time and reduce the incidence of surgical complications.

The high levels of CO 2 and H 2 O in oxy-fuel/oxy-steam combustion are expected to have important effects on the oxidation of ferrous sulfide, which is critical to the understanding of ash deposition. In this work, the kinetics of ferrous sulfide oxidation in CO 2 , H 2 O, or the mixtures of CO 2 and H 2 O are explored on a purposely-designed thermo-gravimetric reactor (TGR). Based on the data obtained from TGR, XRD and SEM, the roles of CO 2 and H 2 O in the oxidation of ferrous sulfide are elucidated. It is found that pyrrhotite (FeS 1+ x ) transformation in CO 2 , H 2 O, or their mixtures is dominated by the oxidation of ferrous sulfide (FeS). The adsorption and desorption elemental reactions of CO 2 or H 2 O on ferrous sulfide are essentially the same. For all cases, the three-dimensional diffusion model can be used to account for the oxidation of ferrous sulfide. The reaction rate constants for the oxidation of ferrous sulfide increase with increasing the partial pressure of the oxidant. The dependence of the reaction rate constant on the partial pressure of CO 2 or H 2 O can be well explained by the Langmuir–Hinshelwood rate forms. In the mixtures of CO 2 and H 2 O, the active sites for the FeS–CO 2 reaction and the FeS–H 2 O reaction are partially independent and partially shared.

The high levels of CO 2 in oxy-fuel combustion are expected to have important effects on the transformation of pyrite, a major contributor to ash deposition. As a successive work to the previous study that explored the chemical role of CO 2 in pyrite decomposition, this paper is purposely designed to investigate the effects of CO 2 on the oxidation of pyrrhotite generated from pyrite decomposition. Pyrrhotite oxidation in pure CO 2 was respectively investigated at 900, 950 and 1000 °C on a well-designed thermo-gravimetric reactor (TGR). The time-resolved data of sample weight loss and gas evolution were collected online by a data collection module and a Horiba PG-350 gas analyzer, respectively. The solid products were characterized by X-ray diffraction (XRD). The results demonstrate that the influence of CO 2 on the oxidation of pyrrhotite is chemical in nature. The transformation of pyrrhotite in CO 2 consists of three stages, i.e., the fast weight loss stage, the slow weight loss stage and the slow weight gain stage. The mechanisms involving CO 2 at these three distinct stages are quite different. At the first stage, ferrous sulfide is formed by the decomposition reaction of pyrrhotite with CO 2 . At the second stage, the oxidation reactions of ferrous sulfide with CO 2 are responsible for the formation of magnetite or hematite. Hematite may also be formed through further oxidation of magnetite by CO 2 . The third stage is dominated by the oxidation of magnetite to form hematite with CO as the only gas product.

The canonical Wnt pathway is vital to bone physiology by increasing bone mass through elevated osteoblast survival. Although investigated extensively in stem cells, its role in osteoblastic MC3T3-E1 cells has not been completely determined. To explore how this pathway is regulated by different conditions, we assessed the anti-apoptotic effects of substance P on the canonical Wnt pathway in MC3T3-E1 cells by treating cells with serum deprivation or serum starving with "substance P," a neuropeptide demonstrated to promote bone growth and stimulate Wnt signaling. The results showed that serum deprivation both induced apoptosis and activated Wnt signal transduction while substance P further stimulated the Wnt pathway via the NK-1 receptor but protected the cells from apoptotic death. Fast-tracking of Wnt signaling by substance P was also noted. These results indicate that nutritional deprivation and substance P synergistically activated the canonical Wnt pathway, a finding that helps to reveal the role of Wnt signaling in bone physiology affected by nutritional deprivation and neuropeptide substance P.

Background Calcitonin gene-related peptide (CGRP) contributes to bone formation by stimulating bone marrow stromal cell (BMSC) proliferation and differentiation. However, the proliferative and apoptotic effects of CGRP on bone marrow-derived endothelial progenitor cells (EPCs) have not been investigated. Methods We tested the effects of CGRP on EPC proliferation and apoptosis by Cell Counting Kit-8, flow cytometry, and studied the effects of CGRP on the expression of proliferation- and apoptosis-related markers in EPCs and the underlying mitogen-activated protein kinase (MAPK) signalling pathway by quantitative polymerase chain reaction and western blotting. Results We detected EPC markers (CD34, CD133 and VEGFR-2) in 7-day cultures and found that CGRP (10− 10–10− 12 M) promoted the proliferation of cultured EPCs, with a peak increase of 30% at 10− 10 M CGRP. CGRP also upregulated the expression of proliferation-associated genes, including cyclin D1 and cyclin E, and increased the percentages of G2/M-phase and S-phase cells after incubation 72 h. CGRP inhibited serum deprivation (SD)-induced apoptosis in EPCs after 24 and 48 h and downregulated the expression of apoptosis-related genes, including caspase-3, caspase-8, caspase-9 and Bax. Phosphorylated (p-)ERK1/2, p-p38 and p-JNK protein levels in EPCs treated with CGRP were significantly lower than those in untreated EPCs. Pre-treatment with the calcitonin receptor-like receptor (CRLR) antagonist CGRP8–37 or a MAPK pathway inhibitor (PD98059, SB203580 or SP600125) completely or partially reversed the pro-proliferative and anti-apoptotic effects and the reduced p-ERK1/2, p-p38 and p-JNK expression induced by CGRP. Conclusion Our results show that CGRP exerts pro-proliferative and anti-apoptotic effects on EPCs and may act by inhibiting MAPK pathways. Electronic supplementary material The online version of this article (10.1186/s12953-018-0146-4) contains supplementary material, which is available to authorized users.

In this study, novel core-shell catalyst with a new ternary heterostructure was synthesized (Fe0@POCN/CQDs) for the degradation of tetracycline (TC). The TEM results showed that the Fe0 particles were wrapped in POCN material and many nano CQDs were uniformly dispersed in the material. The new ternary nanocomposite exhibits excellent photocatalytic activity for the removal of TC, which was approximately 4.76 times higher than that of GCN. The enhancement of photocatalytic activity was attributed to the effective heterojunction as well as the multiply synergistic effects of POCN combined with Fe0 and CQDs, which was beneficial for retardation of recombination rate of photogenerated electron–hole pairs and generation of more free radicals for the oxidation of TC. Besides, the reactive oxygen species (ROS) of h+, •O2− and •OH played pivotal roles in the degradation of TC by Fe0@POCN/CQDs during the photocatalytic reaction. At the same times, sulfate radical (SO4•-) and hydroxyl radical (•OH) highlighted the dominant role in the degradation process compared with other free radicals under persulfate hybrid mixture system (PS system), which was further confirmed by radical scavenger experiments and electron spin resonance (ESR) analysis. The response surface methodology (RSM) study indicated that the optimal removal parameters of tetracycline could reach 97.57% within 30 min under PS system. In addition, the possible degradation pathway intermediates of TC were studied by HPLC-MS and the reaction catalytic activity mechanism of Fe0@POCN/CQDs/persulfate system was discussed.

Exchangeable calcium (Ca) in coals has significant catalysis during gasification. In previous work, coals were usually pyrolyzed for different time periods before char gasification. The extent of char aging during pyrolysis may change the state of Ca, and affect its catalytic behavior during gasification. This speculation is investigated by characterizing different aged chars and their in-situ gasification in a thermogravimetric reactor. Calcium-exchanged coal samples were first isothermally pyrolyzed at different pyrolysis time and then in-situ gasified in CO2 or steam at different temperatures. The pyrolyzed and partially gasified chars were collected and analyzed. The results show that char aging significantly changes the state and dispersion of Ca. While the nascent chars (product of 1-min pyrolysis) show no visible Ca-containing particles on the surfaces, the aged chars (product of 20-min pyrolysis) show evident CaO particles ranging from a few to tens of nanometers. During gasification, the extent of char aging does not change the catalytic action of Ca in either CO2 (surface recession mode) or steam (channeling mode). Increasing temperature favors the gasification reactivity of both nascent and aged chars in CO2, and that of aged chars in steam. However, the gasification reactivity of the nascent chars in steam does not seem to be considerably affected by increasing temperature. The increase of catalytic activity may be mostly offset by the decrease of Ca dispersion.

Neuropeptide Y (NPY) is a neuropeptide secreted by sensory nerve fibers distributed in the marrow and vascular canals of bone tissue. However, the effect of NPY on the osteogenic ability of bone marrow mesenchymal stem cells (BMSCs) remains controversial and has not been thoroughly investigated. To explore the osteogenic activity and the migration and VEGF expression capabilities of BMSCs affected by NPY, as well as the underlying mechanisms, we investigated the potential relationships among NPY, osteoblastic differentiation, angiogenesis and canonical Wnt signaling in BMSCs. NPY was observed to regulate osteoblastic differentiation at concentrations ranging from 10(-8) to 10(-12)mol/L, and the effects of NPY on the levels of Wnt signaling proteins were detected using Western blotting. To unravel the underlying mechanism, BMSCs were treated with NPY after pretreatment with the NPY-1R antagonist PD160170 or the Wnt pathway antagonist DKK1, and gene expression levels of Wnt signaling molecules and osteoblastic markers were determined by qPCR. Our results indicated that NPY significantly promoted osteoblastic differentiation of BMSCs in a concentration-dependent manner and up-regulated the expression levels of proteins including β-catenin and p-GSK-3β and the mRNA level of β-catenin. Moreover, NPY promoted the translocation of β-catenin into nucleus. The effects of NPY were inhibited by PD160170 or DKK1. Additionally, NPY enhanced the ability of BMSCs to migrate and promoted the expression of vascular endothelial growth factor (VEGF) as measured by immunocytochemical staining, qPCR and Western blot. These results suggested that NPY may stimulate osteoblastic differentiation via activating canonical Wnt signaling and enhance the angiogenic capacity of BMSCs.

The pelletization of carbide slag is necessary for its practical application in the calcium looping process (CLP). In this work, CaO-based pellets were prepared from carbide slag waste via a novel method of extrusion–spheronization. However, this granulation method results in a loss of specific surface area and, consequently, inferior CO2 sorption performance of the carbide slag pellets. Two types of biomass-based pore-forming materials (microcrystalline cellulose and rice husk) were used for the first time to modify the pore structures of the pellets, and thus enhance their CO2 sorption performance. The addition of 20 wt.% microcrystalline cellulose is effective in improving the CO2 sorption of carbide slag pellets, displaying a high conversion of 52.64% in the 25th cycle. However, the additions of 10 and 20 wt.% rice husk both result in inferior cyclic CO2 capture performance owing to the aggravated sorbent sintering caused by the new eutectics, which are from the combination of aluminosilicate with the potassium contained in the rice husk. The pellets doped with 20 wt.% pre-washed rice husk (most potassium removed) display the highest 25th carbonation conversion of 51.02%, which is almost 1.46 times that of the pellets doped with raw rice husk. The addition of pore-forming materials weakens the pellets’ mechanical strength, and 5–10 wt.% addition of cement could enhance the mechanical strength and maintain the relatively good CO2 sorption performance of the pellets.

In this work, a series of catalysts were successfully fabricated and exhibits ammonia nitrogen degradation performance under UV and simulated sunlight irradiation. Among in, the as-prepared rGO/P-HC/TiO2 heterostructure extends its visible radiation response and shows much higher efficient photocatalytic activity for ammonia nitrogen than those of other catalysts, of which the removal efficiency could reach 93.0 % under UV-light irradiation. The high photocatalytic activity possibly related to electron-hole pairs photogenerated under UV or visible light irradiation were effectively separated on the surface of the as-prepared rGO/P-HC/TiO2 heterostructure, and the synergistic effect of rGO, P-HC and TiO2, and thus increase of the photocatalytic activity. The reactive species trapping experimental results reveal that the h+ is the dominantly active species in degrading ammonia nitrogen in the photocatalytic process.

Exchangeable calcium (Ca) in coal has excellent catalysis on gasification reaction. Magnesium (Mg) may have effects on this process, but the previous researches are limited and the influence mechanism is still unclear. Thus, this work aims to investigate the influence of Mg on Ca catalytic gasification process. A low-rank coal was demineralized and then loaded with Ca and Mg, separately or jointly, by ion exchange. Subsequently, the samples were gasified in CO2 or steam at 800 ℃–900 ℃ in a specially designed thermogravimetric reactor. The partially-gasified chars were collected and analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption tests, and temperature-programmed desorption (TPD) with a mass spectrometer (MS). The results show that the exchangeable Ca and Mg in coal form Ca-containing particles (CaCO3 or CaO) and MgO particles, respectively. Moreover, Mg has different impacts on the catalytic activity of Ca during CO2 and steam gasification. In CO2, Mg has a promoting effect. It is rather evident at 800 ℃, resulting from that MgO inhibits the sintering of large CaCO3 particles. These particles are mainly on the char surface and the pore structure is less developed. On the contrary, in steam, Mg has an inhibiting effect. It reduces the calcium-carbon interface and inhibits the channeling reaction process.

In order to control PM10 (of an aerodynamic diameter of 10 μm or less) emissions from biochar combustion, the effects of various occurrence modes of inorganic components on PM10 formation are investigated. Two typical biochars (torrefied willow and wheat) were processed through sequential extraction procedures followed by combustion experiments in a high-temperature drop-tube furnace at 1400 °C. The generated particulate matter was characterised. The PM1 emissions during air combustion were linearly related to the content of K/Cl/S in water-soluble/ion-exchangeable forms, which are easily vaporised. The nucleation and coagulation of KCl/K2SO4 in gaseous species forming most of the PM1 resulted in the above-mentioned strong correlation. The PM1-10 emissions had a not very good linear relationship with the various forms of inorganic elements, and they were mainly related to the acid-soluble components. The catalysed sintering of CaO and coalescence/fragmentation of Ca-containing minerals formed most of the PM1-10 (torrefied willow). The Ca in torrefied willow mainly exists in an acid-soluble form, which interfered with the effect of other elements. The coalescence/fragmentation of Si-containing minerals in torrefied wheat generated most of the PM1-10. After various washing procedures, the different forms of Ca/K were removed and the silicate decreased during combustion, leading to a weakness in coalescence. This led to the above-mentioned relationship. When the combustion atmosphere was switched to oxy-fuel mode, the great contribution of acid-soluble Ca to PM1-10 (torrefied willow)/water-soluble K to PM1 (torrefied wheat) still exists, indicating that they were less affected by the combustion conditions.

Zhundong low-rank coal is very likely to be utilized extensively in oxy-fired boilers in the near future. Its PM10 (particulate matter with an aerodynamic diameter of &le, 10 &mu, m) emission behaviors during oxy-fuel combustion need to be carefully studied before its large-scale use. The present study examines the emission behaviors of inorganic ultrafine particles (PM0.5, with an aerodynamic diameter of &le, 0.5 &mu, m), as well as PM10 during the combustion of Zhundong coal in air and oxy-fuel conditions (O2/CO2) at three characterized O2 input fractions, i.e., 21, 27 and 32 vol.%. The combustion experiments were carried out in a high-temperature drop-tube furnace (HDTF) at a combustion temperature of 1500 &deg, C. The results show that PM0.5 is composed of Na, S, Mg and Ca, with total fractions of ~90%, while PM0.5&ndash, 10 (with an aerodynamic diameter between 0.5 and 10 &mu, m) predominantly contains Ca (~50&ndash, 65%). At three characterized oxygen fractions during oxy-fuel combustion (OXY21, 27 and 32), the promoted O2 fraction was found to increase the yields of both PM0.5 and PM0.5&ndash, 10. A higher particle-burning temperature and a lower CO2 fraction promote the reactions of both organically bound elements and inorganic minerals, increasing the partitioning of Mg and Ca and causing an increased yield of PM0.5. The yield of PM0.5 from air is high and similar to that from OXY32 while the yield of PM0.5&ndash, 10 from air is similar to that from OXY27. The high yield of PM0.5 from air is mainly generated by the highest yields of Ca in four conditions.