Oxidation Behavior of Tyranno ZMI-SiC Fiber/SiC-SiBC Matrix Composite from 800 to 1200 °C

In this work, the self-healing Si-B-C matrix-modified ZMI-SiC fiber/SiC (SiC/SiC-SiBC) composite was prepared by a combined process of chemical vapor infiltration, slurry infiltration, and liquid silicon infiltration. The weight changes of the as-fabricate composite after oxidation at 800, 1000, and 1200 °C for 100 h were −0.41%, −0.06%, +0.05%, respectively. The corresponding strength retention ratios were 75%, 99%, 100%, respectively. With the increase of oxidation temperature, coating cracks would be closed. A dense oxidation film was formed with the oxidation of the SiBC matrix, preventing the oxidation of interphase and fiber and leading to excellent oxidation resistance at 1000 and 1200 °C.

Droplet Imbibition into Paper Coating Layer: Pore-Network Modeling Simulation

Liquid penetration into thin porous media such as paper is often simulated using continuum-scale single-phase Darcy's law. The underlying assumption was that a sharp invasion front percolates through the layer. To explore this ambiguous assumption and to understand the controlling pore-scale mechanisms, we have developed a dynamic pore-network model to simulate imbibition of a wetting phase from a droplet into a paper coating layer. The realistic pore structures are obtained using the FIB-SEM imaging of the coating material with a minimum resolution of 3.5 nm. Pore network was extracted from FIB-SEM images using Avizo software. Data of extracted pore network are used for statistically generating pore network. Droplet sizes are chosen in the range of those applicable in inkjet printing. Our simulations show no sharp invasion front exists and there is the presence of residual non-wetting phase. In addition, penetration of different sizes of droplets of different material properties into the pore network with different pore body and pore throat sizes are performed. We have found an approximately linear decrease in droplet volume with time. This contradicts the expected t -behavior in vertical imbibition that is obtained using macroscopic single-phase Darcy's law. With increase in flow rate, transition of imbibition invasion front from percolation-like pattern to a more sharper one with less trapping of non-wetting phase is also reported. Our simulations suggest that the single-phase Darcy's law does not adequately describe liquid penetration into materials such as paper coating layer. Instead Richards equation would be a better choice.

Cortistatin inhibits arterial calcification in rats via GSK3β/β-catenin and protein kinase C signalling but not c-Jun N-terminal kinase signalling

AIM

Cortistatin (CST) is a newly discovered endogenous active peptide that exerts protective effects on the cardiovascular system. However, the relationship between CST and aortic calcification and the underlying mechanism remain obscure. Therefore, we investigated effects of CST on aortic calcification and its signalling pathways.

METHODS

Calcium content and alkaline phosphatase (ALP) activity were measured using the o-cresolphthalein colorimetric method and ALP assay kit respectively. Protein expression of smooth muscle (SM)-ɑ-actin, osteocalcin (OCN), β-catenin, glycogen synthase kinase 3β (GSK3β), p-GSK3β, protein kinase C (PKC), p-PKC, c-Jun N-terminal kinase (JNK) and p-JNK was determined using Western blotting.

RESULTS

In aorta from a rat vitamin D3 calcification model, CST abrogated calcium deposition and pathological damage, decreased the protein expression of OCN and β-catenin and increased SM-ɑ-actin expression. In a rat cultured vascular smooth muscular cell (VSMC) calcification model induced by β-glycerophosphate (β-GP), CST inhibited the increase in ALP activity, calcium content and OCN protein and the decrease in SM-α-actin expression. CST also inhibited the β-GP-induced increase in p-GSK3β and β-catenin protein (both P < .05). The inhibitory effects of CST on ALP activity, calcium deposition and β-catenin protein were abolished by pretreatment with lithium chloride, a GSK3β inhibitor. CST promoted the protein expression of p-PKC by 68.5% (P < .01), but not p-JNK. The ability of CST to attenuate β-GP-induced increase in ALP activity, calcium content and OCN expression in the VSMC model was abolished by pretreatment with the PKC inhibitor Go6976.

CONCLUSION

These results indicate that CST inhibits aortic calcification and osteogenic differentiation of VSMCs likely via the GSK3β/β-catenin and PKC signalling pathways, but not JNK signalling pathway.

Hyperfibrinogenemia is Significantly Associated with an Increased Risk of In-hospital Mortality in Acute Ischemic Stroke Patients

BACKGROUND

The impact of hyperfibrinogenemia on short-term outcomes after acute ischemic stroke (AIS) is still not well understood.

OBJECTIVE

We investigated the association between hyperfibrinogenemia upon hospital admission and the short-term prognosis of AIS patients.

METHODS

A total of 3,212 AIS patients enrolled from December 2013 to May 2014 across 22 hospitals in Suzhou city were included in the present study. Hyperfibrinogenemia was defined as having a serum fibrinogen＞4.0g/L. Cox proportional hazard and logistic regression models were used to estimate the effect of hyperfibrinogenemia on all-cause in-hospital mortality and poor discharge outcome (modified Rankin Scale score≥3) in AIS patients.

RESULTS

During hospitalization, 106 patients (3.3%) died from all-cause and 1226 (38.2%) patients experienced poor functional outcome at discharge. Multivariable model adjusted for age, sex, baseline National Institutes of Health Stroke Scale score, white blood cell count and other covariates, showed that hyperfibrinogenemia was associated with a 1.76-fold increase in the risk of in-hospital mortality (hazard ratio [HR] 1.76; 95% confidence interval [CI], 1.10-2.81; P-value=0.019). However, there was no significant association between hyperfibrinogenemia and poor outcome at discharge (adjusted odds ratios[OR]1.15; 95% CI 0.86-1.53; P-value=0.338). Sensitivity and subgroup analyses also confirmed a significant association between hyperfibrinogenemia and in-hospital mortality.

CONCLUSION

In patients with AIS, hyperfibrinogenemia at the time of admission was independently associated with increased in-hospital mortality.

Tunable dielectric properties of mesoporous carbon hollow microspheres via textural properties

In this study, mesoporous carbon hollow microspheres (PCHMs) with tunable textural properties have been prepared through a facile hard template etching method. The PCHMs were characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Raman spectra, and nitrogen adsorption and desorption systems. Uniform PCHMs with shell thickness ranging from 23 nm to 55 nm are realized. PCHMs with different textural properties can regulate dielectric and electromagnetic (EM) wave absorption effectively. The composite of paraffin wax mixed with 10 wt% PCHMs (the shell thickness of PCHMs is 35 nm) exhibits a minimum coefficient value of -53.8 dB at 8.8 GHz, with a thickness of 3.4 mm. Besides, it is remarkable that the effective absorption bandwidth covers all the X band with as low as a 10 wt% filler ratio, compared with other spherical EM wave absorbers. The excellent EM wave absorption capability of PCHMs can be ascribed to the better impendence matching and strong EM wave attenuation constant based on tunable textural properties. Our results provide a facile strategy to tune dielectric properties of spherical carbon absorbers based on textural properties, and can be extended to other spherical absorbers.

Bacteriocin biosynthesis contributes to the anti-inflammatory capacities of probiotic Lactobacillus plantarum

Plantaricin EF (PlnEF) is a class IIb bacteriocin produced by Lactobacillus plantarum. We compared L. plantarum NCIMB8826 and LM0419, a plnEFI deletion mutant of that strain lacking plnEF and the gene for the cognate immunity protein plnI, in a 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced mouse model of acute inflammatory bowel disease. Mice fed either L. plantarum NCIMB8826 or LM0419 were not protected against TNBS according to either disease activity or histology (Ameho) scores. Mice consuming NCIMB8826 exhibited intermediate (non-significant) levels of colonic tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) that ranged between the TNBS-treated animals and healthy controls. By comparison, TNF-α and IL-6 quantities were elevated in mice given L. plantarum LM0419 and equivalent to mice given TNBS alone. Both strains survived digestive tract transit in equal numbers and did not result in global changes to the bacterial composition in the intestine according to 16S rRNA gene sequencing either prior to or after TNBS administration. Examination of intestinal taxa showed that mice consuming wild-type L. plantarum, but not LM0419 contained lower proportions of Mucispirillum (Deferribacteres phylum) in the faeces prior to TNBS administration and Parabacteroides (Bacteroidetes phylum) in the caecum after disease induction. Parabacteroides also positively correlated with disease activity and histology scores. These findings suggest a role for PlnEFI production by L. plantarum in benefiting digestive tract health.

Integrative analyses reveal biological pathways and key genes in psoriasis

BACKGROUND

Psoriasis is a complex disease influenced by both genetic and environmental factors with abnormal gene expression in lesional skin. However, no studies are available on genome-scale gene expression of psoriatic lesions in the Chinese population. In addition, systematic studies on the biological pathways, pathogenicity and interaction networks of psoriasis-related genes with abnormal expression profiles require further investigation.

OBJECTIVES

To further explore the associated pathways in psoriasis by functional analysis and to identify the key genes by gene pathogenicity analysis.

METHODS

We performed RNA sequencing on 60 skin biopsy samples from patients with psoriasis and healthy controls to identify the primary differentially expressed genes in psoriatic lesional skin. We retrieved all reported psoriasis-associated genes and performed integrative analyses covering gene expression profiling, pathway analysis, gene pathogenicities and protein-protein interaction networks.

RESULTS

We found that internal and external stimuli may activate immunoinflammatory responses to promote the development of psoriasis. Pathways associated with infectious diseases and cancers were identified by functional and pathway analyses. The gene pathogenicity analysis revealed five key genes in psoriasis: PPARD, GATA3, TIMP3, WNT5A and PTTG1.

CONCLUSIONS

Our analyses showed that genes contributed to the pathogenesis of psoriasis by activating risk pathways with components abnormality in expression. We identified five potentially pathogenic genes for psoriasis that may serve as important biomarkers for the diagnosis and treatment.

HCV viraemia associates with NK cell activation and dysfunction in antiretroviral therapy-treated HIV/HCV-co-infected subjects

The impact of hepatitis C virus (HCV) RNA levels on immune status in chronically HCV mono-infected when compared to HIV/HCV co-infected on antiretroviral therapy (ART) remains poorly understood. A total of 78 African American subjects HCV viraemic/naïve to HCV treatment (33 HCV genotype 1 mono-infected, 45 ART-treated HIV/HCV genotype 1 co-infected) were studied. Clinical and liver enzyme measurements were performed. Whole blood was analysed for immune subset changes by flow cytometry. Peripheral blood mononuclear cells (PBMC) were used for same-day constitutive and in vitro Interferon (IFN)-α-induced signal transducer and activator of transcription (STAT) phosphorylation, K562 target cell lysis and K562 target cell recognition-mediated IFN-γ production. Statistical analysis was performed using R (2.5.1) or JMP Pro 11. While both groups did not differ in the level of liver enzymes, HIV/HCV had higher T-cell activation/exhaustion, and constitutive STAT-1 phosphorylation compared to HCV. In contrast, CD4⁺ FoxP3⁺ CD25⁺ frequency, IFN-αR expression on NK cells, as well as constitutive and IFN-α-induced direct cytotoxicity were lower in HIV/HCV. Linear regression models further supported these results. Finally, increase in HCV viral load and CD4⁺ T-cell count had an opposite effect between the two groups on NK cell activity and T-cell activation, respectively. HCV viral load in ART-treated HIV/HCV co-infection was associated with greater immune activation/exhaustion and NK dysfunction than HCV viral load alone in HCV mono-infection. The more pronounced immune modulation noted in ART-treated HIV-co-infected/untreated HCV viraemic subjects may impact HCV disease progression and/or response to immunotherapy.

Genetic variants of microRNA processing genes and risk of non-syndromic orofacial clefts

OBJECTIVE

MicroRNA (miRNA) processing genes play important roles in the craniofacial development. The aim of this study was to explore the associations between single nucleotide polymorphisms (SNPs) of miRNA processing genes with the risk of non-syndromic orofacial clefts (NSOC).

METHODS

We genotyped 12 potentially functional SNPs from seven miRNA processing genes (GEMIN3, DROSHA, DGCR8, GEMIN4, PIWIL1, XPO5, and DICER) in a case-control study of 602 NSOC cases and 605 controls.

RESULTS

Two SNPs were associated with the susceptibility of CL/P: rs10719 in DROSHA led to an increased risk of cleft lip with or without palate (CL/P) (GA/AA: p = .024, OR = 1.33, 95% CI = [1.04, 1.70]; GG + GA/AA: p = .037, OR = 1.29, 95% CI = [1.02, 1.63]), while rs493760 in DROSHA (CC/TT: p = .049, OR = 0.58, 95% CI = [0.34, 0.99]) could reduce the risk of CL/P. In addition, rs10719 (A)-rs493760 (C) haplotype contributed to a decreased risk of CL/P (OR = 0.77, 95% CI = [0.63, 0.94]), whereas the rs10719 (G)-rs493760 (C) haplotype contributed to the increased risk of cleft palate only (CPO) (OR = 2.70, 95% CI = [1.15, 6.35]). However, there was no difference observed in these SNPs after the Bonferroni correction.

CONCLUSION

Taken together, our results provided the potential evidence that rs10719 and rs493760 might contribute to the risk of CL/P and suggested potential genetic basis and mechanisms of CL/P. The lack of association between these SNPs and CPO might be due to the limited sample size of CPO subgroup.

Carbon Nanotube-Multilayered Graphene Edge Plane Core-Shell Hybrid Foams for Ultrahigh-Performance Electromagnetic-Interference Shielding

Materials with an ultralow density and ultrahigh electromagnetic-interference (EMI)-shielding performance are highly desirable in fields of aerospace, portable electronics, and so on. Theoretical work predicts that 3D carbon nanotube (CNT)/graphene hybrids are one of the most promising lightweight EMI shielding materials, owing to their unique nanostructures and extraordinary electronic properties. Herein, for the first time, a lightweight, flexible, and conductive CNT-multilayered graphene edge plane (MLGEP) core-shell hybrid foam is fabricated using chemical vapor deposition. MLGEPs are seamlessly grown on the CNTs, and the hybrid foam exhibits excellent EMI shielding effectiveness which exceeds 38.4 or 47.5 dB in X-band at 1.6 mm, while the density is merely 0.0058 or 0.0089 g cm^-3 , respectively, which far surpasses the best values of reported carbon-based composite materials. The grafted MLGEPs on CNTs can obviously enhance the penetration losses of microwaves in foams, leading to a greatly improved EMI shielding performance. In addition, the CNT-MLGEP hybrids also exhibit a great potential as nano-reinforcements for fabricating high-strength polymer-based composites. The results provide an alternative approach to fully explore the potentials of CNT and graphene, for developing advanced multifunctional materials.

Lithium enhances alveolar bone formation during orthodontic retention in rats

OBJECTIVE

To investigate the effect of lithium on alveolar bone formation during orthodontic retention in rats.

MATERIALS AND METHODS

After 2 weeks of orthodontic tooth movement (OTM), 42 8-week-old male Wistar rats were randomly divided into two orthodontic retention groups: one without (control) and the other with LiCl treatment (LiCl group). Samples were collected on days 0, 3, 7 and 14 during the retention period. We evaluated the bone volume/total volume (BV/TV) ratio and new bone formation in the region of interests (ie, the root, the periodontal ligament and the adjacent alveolar bone around the distal buccal surface of the distal root of the maxillary first molar). We performed quantitative analyses, including histology, histomorphometry and immunohistochemistry to identify Runx2 and Osterix expression.

RESULTS

The density of trabecular bone, the quantity of osteoblasts and the expression of osteogenic markers, Runx2 and Osterix, were significantly higher in the LiCl group than in the control group during the orthodontic retention period.

CONCLUSION

LiCl enhances alveolar bone formation during orthodontic retention in rats.

Laminated and Two-Dimensional Carbon-Supported Microwave Absorbers Derived from MXenes

Microwave absorbers with layered structures that can provide abundant interfaces are highly desirable for enhancing electromagnetic absorbing capability and decreasing the thickness. The atomically thin layers of two-dimensional (2D) transition-metal carbides (MXenes) make them a convenient precursor for synthesis of other 2D and layered structures. Here, laminated carbon/TiO₂ hybrid materials composed of well-aligned 2D carbon sheets with embedded TiO₂ nanoparticles were synthesized and showed excellent microwave absorption. Disordered 2D carbon layers with an unusual structure were obtained by annealing multilayer Ti₃C₂ MXene in a CO₂ atmosphere. The minimum reflection coefficient of laminated carbon/TiO₂ composites reaches -36 dB, and the effective absorption bandwidth ranges from 3.6 to 18 GHz with the tunable thickness from 1.7 to 5 mm. The effective absorption bandwidth covers the whole Ku band (12.4-18 GHz) when the thickness of carbon/TiO₂/paraffin composite is 1.7 mm. This study is expected to pave the way to the synthesis of carbon-supported absorbing materials using a large family of 2D carbides.

Flexible and Thermostable Graphene/SiC Nanowire Foam Composites with Tunable Electromagnetic Wave Absorption Properties

Three-dimensional (3D) flexible foams consisting of reduced graphene oxides (rGO) and in situ grown SiC nanowires (NWs) were prepared using freeze-drying and carbothermal reduction processes. By means of incorporating SiC nanowires into rGO foams, both the thermostability and electromagnetic absorption of the composites were improved. It was demonstrated that rGO/SiC NW foams were thermostable beyond ∼630 °C (90% weight retention in air atmosphere). As expected, rGO/SiC NW foams in the poly(dimethylsiloxane) matrix achieved effective absorption in the entire X-band (8.2-12.4 GHz) with a thinner thickness (3 mm) in comparison with those of the pure rGO foams. It is revealed that SiC nanowires with abundant stacking faults, twinning interfaces, and bridged junctions play an important role in the enhanced electromagnetic absorption performance, in addition to the contribution of interconnected graphene networks. Hierarchical rGO/SiC NW foams not only are efficient absorbers in the critical environments but also can be applied in photocatalytic and thermal-management fields.

Relationships among Bone Quality, Implant Osseointegration, and Wnt Signaling

A variety of clinical classification schemes have been proposed as a means to identify sites in the oral cavity where implant osseointegration is likely to be successful. Most schemes are based on structural characteristics of the bone, for example, the relative proportion of densely compact, homogenous (type I) bone versus more trabeculated, cancellous (type III) bone. None of these schemes, however, consider potential biological characteristics of the bone. Here, we employed multiscale analyses to identify and characterize type I and type III bones in murine jaws. We then combined these analytical tools with in vivo models of osteotomy healing and implant osseointegration to determine if one type of bone healed faster and supported osseointegration better than another. Collectively, these studies revealed a strong positive correlation between bone remodeling rates, mitotic activity, and osteotomy site healing in type III bone and high endogenous Wnt signaling. This positive correlation was strengthened by observations showing that the osteoid matrix that is responsible for implant osseointegration originates from Wnt-responsive cells and their progeny. The potential application of this knowledge to clinical practice is discussed, along with a theory unifying the role that biology and mechanics play in implant osseointegration.

Role of NKG2D in cytokine-induced killer cells against lung cancer

It has been previously demonstrated that cytokine-induced killer (CIK) cells possess potent cytotoxicity against various cancer cells, including lung cancer cells. However, the mechanism by which CIK cells recognize lung cancer cells has not been understood. The interaction between killer cell lectin like receptor K1 (NKG2D) receptor and NKG2D ligands was demonstrated to serve an important role in target cell killing by natural killer cells. The present study investigated whether NKG2D receptor and NKG2D ligand interactions are involved in the CIK-directed killing of lung cancer cells. The expression of MICA and ULBP2 was detected in tumor and healthy tissue samples. The expression of MICA and ULBP2 in tumor tissue samples was higher compared with that in the healthy control tissue. The expression of NKG2D ligands was analyzed in A549 and Q56 cells through reverse transcription-quantitative polymerase chain reaction and flow cytometry. The results demonstrated that the lung cancer cell lines markedly expressed the NKG2D ligands. Furthermore, NKG2D ligand-expressing lung cancer cells were targeted by CIK cells, which was partially blocked by treating CIK cells with an antibody against NKG2D. The data of the current study has demonstrated that the NKG2D-NKG2D ligand interaction serves an essential role in mediating lung cancer cell killing by CIK cells.

Carbon Hollow Microspheres with a Designable Mesoporous Shell for High-Performance Electromagnetic Wave Absorption

In this work, mesoporous carbon hollow microspheres (PCHMs) with designable mesoporous shell and interior void are constructed by a facile in situ stöber templating approach and a pyrolysis-etching process. The PCHMs are characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, Raman spectroscopy, and nitrogen adsorption and desorption system. A uniform mesoporous shell (pore size 4.7 nm) with a thickness of 55 nm and a cavity size of 345 nm is realized. The composite of paraffin mixed with 20 wt % PCHMs exhibits a minimum reflection coefficient (RC_min) of -84 dB at 8.2 GHz with a sample thickness of 3.9 mm and an effective absorption bandwidth (EAB) of 4.8 GHz below -10 dB (>90% electromagnetic wave is attenuated). Moreover, the composite of phenolic resin mixed with 20 wt % PCHMs exhibits an ultrawide EAB of 8 GHz below -10 dB with a thinner thickness of 2.15 mm. Such excellent electromagnetic wave absorption properties are ascribed to the large carbon-air interface in the mesoporous shell and interior void, which is favorable for the matching of characteristic impedance as compared with carbon hollow microspheres and carbon solid microspheres. Considering the excellent performance of PCHMs, we believe the as-fabricated PCHMs can be promising candidates as highly effective microwave absorbers, and the design philosophy can be extended to other spherical absorbers.