Associations between abdominal obesity indices with hypertension in type 2 diabetes mellitus: Chinese visceral adiposity index

PURPOSE

This research was performed to evaluate the relationship between hypertension (HTN) and abdominal obesity index in patients with type 2 diabetes mellitus (T2DM).

METHODS

Totally 1657 participants with T2DM (mean age 54 ± 12 years; 38.02% female) were enrolled. They were divided into the groups of HTN (n = 775) and non-HTN (n = 882). Anthropometric and biochemical indicators were measured and collected. A bioelectrical impedance analyzer was used to measure visceral and subcutaneous fat areas.

RESULTS

Compared with the HTN group, the non-HTN group had a lower level of Chinese visceral adiposity index (CVAI) (p < 0.001). Meanwhile, among tertiles of CVAI, as CVAI increased, the proportion of patients with HTN increased, which was 33.51%, 44.30%, and 62.50%, respectively. CVAI was shown to have a significant positive correlation with HTN. (r = 0.258, p < 0.001). CVAI was independently related to an elevated risk of HTN by binary logistic regression analyses, and the OR was (95% CI) 1.013 (1.010-1.016, p < 0.001) after adjustment. The area under the receiver operating characteristic curve (AUC) of CVAI predicted HTN in T2DM patients was greater than those of other abdominal obesity indices (p < 0.001).

CONCLUSION

We found that CVAI was highly positively correlated with HTN in T2DM. Compared with other indices of abdominal obesity, such as WC, BMI, WHR, VAI, and LAP, the CVAI showed superior discriminative ability in T2DM complicated with HTN. Therefore, more attention should be paid to CVAI in T2DM.

Immune checkpoint inhibitor-associated new-onset primary adrenal insufficiency: a retrospective analysis using the FAERS

BACKGROUND

Our study aimed to investigate the prevalence and demographic characteristics of immune checkpoint inhibitor-associated primary adrenal insufficiency (ICI-PAI) and to explore the risk factors of its clinical outcome using data from the US FDA Adverse Event Reporting System (FAERS).

METHODS

This was a retrospective study. All cases of new-onset or newly diagnosed primary adrenal insufficiency associated with FDA-approved ICIs from 1 January 2007 to 31 December 2020 were identified and collected using FAERS. Data on age, sex category, body weight of the participating individuals, the reporting year and the prognosis of cases, and other accompanying endocrinopathies related to ICIs, were analysed.

RESULTS

The incidence of ICI-PAI was 1.03% (1180/114121). Of the 1180 cases of PAI, 46 were "confirmed PAI", and 1134 were "suspected PAI". Combination therapy with anti-CTLA-4 and anti-PD-1 was related to a higher risk of PAI compared with the anti-PD-1-only group (χ² = 92.88, p < 0.001). Male and elderly individuals showed a higher risk of ICI-PAI (male vs. female, 1.17% vs. 0.94%, χ² = 12.55, p < 0.001; age < 65 vs. ≥ 65, 1.20 vs. 1.41%, χ² = 6.89, p = 0.009). The co-occurrence rate of endocrinopathies other than PAI was 24.3%, which showed a higher trend in patients on nivolumab-ipilimumab treatment than in those on PD-1 inhibitors (χ² = 3.227, p = 0.072). Body weight was negatively associated with the risk of death in the study population [p = 0.033 for the regression model; B = - 0.017, OR 0.984, 95% CI (0.969-0.998), p = 0.029].

CONCLUSION

ICI-associated PAI is a rare but important irAE. Male and elderly patients have a higher risk of ICI-PAI. Awareness among clinicians is critical when patients with a lower body weight develop PAI, which indicates a higher risk of a poor clinical outcome.

Potential biomarkers in the fibrosis progression of nonalcoholic steatohepatitis (NASH)

PURPOSE

Fibrosis is the only histological feature reflecting the severity and prognosis of nonalcoholic steatohepatitis (NASH). We aim to explore novel genes associated with fibrosis progression in NASH.

METHODS

Two human RNA-seq datasets were downloaded from the public database. Weighted gene co-expression network analysis (WGCNA) was used to identify their co-expressed modules and further bioinformatics analysis was performed to identify hub genes within the modules. Finally, based on two single-cell RNA-seq datasets from mice and one microarray dataset from human, we further observed the expression of hub genes in different cell clusters and liver tissues.

RESULTS

7 hub genes (SPP1, PROM1, SOX9, EPCAM, THY1, CD34 and MCAM) associated with fibrosis progression were identified. Single-cell RNA-seq analysis revealed that those hub genes were expressed by different cell clusters such as cholangiocytes, natural killer (NK) cells, and hepatic stellate cells (HSCs). We also found that SPP1 and CD34 serve as markers of different HSCs clusters, which are associated with inflammatory response and fibrogenesis, respectively. Further study suggested that SPP1, SOX9, MCAM and THY1 might be related to NASH-associated hepatocellular carcinoma (HCC). Receiver operating characteristic (ROC) analysis showed that the high expression of these genes could well predict the occurrence of HCC. At the same time, there were significant differences in metabolism-related pathway changes between different HCC subtypes, and SOX9 may be involved in these changes.

CONCLUSIONS

The present study identified novel genes associated with NASH fibrosis and explored their effects on fibrosis from a single-cell perspective that might provide new ideas for the early diagnosis, monitoring, evaluation, and prediction of fibrosis progression in NASH.

Dlx3 Ubiquitination by Nuclear Mdm2 Is Essential for Dentinogenesis in Mice

Dentin is a major mineralized component of teeth. Odontoblasts are responsible for synthesis and secretion of dentin matrix. Previously, it has been demonstrated in a cell culture system that the E3 ubiquitin ligase, murine double minute 2 (Mdm2), promotes odontoblast-like differentiation of mouse dental papilla cells (mDPCs) by ubiquitinating p53 and the odontoblast-specific substrate Dlx3. However, whether Mdm2 plays an essential role in vivo in odontoblast differentiation and dentin formation remains unknown. In this study, we investigated the in vivo functions of Mdm2 using Dmp1-Cre;Mdm2 flox/flox mice combined with multiple histological and molecular biological methods. The results showed that Mdm2 deletion in the odontoblast layer led to defects in odontoblast differentiation and dentin formation. Unexpectedly, specific inhibition of the Mdm2-p53 axis in wild-type mice by injection of a small-molecule inhibitor Nutlin-3a indicated that the role of Mdm2 in dentinogenesis was p53 independent, which was inconsistent with the previous in vitro study. In situ proximity ligation assay (PLA) showed that Mdm2 interacted with and ubiquitinated Dlx3 in the odontoblast nucleus of mouse molars. Dlx3 promoted the translocation of Mdm2 to the nucleus, and in turn, the nuclear Mdm2 mediated ubiquitination of Dlx3 and promoted the odontoblast-like differentiation of mDPCs. Dlx3 interacted with Mdm2 through its C-terminal domain. Deletion of the C-terminal domain of Dlx3 reversed the enhanced odontoblast-like differentiation and the activation of Dspp promoter mediated by overexpression of wild-type or nuclear Mdm2. Our findings suggest that nuclear Mdm2 mediates ubiquitination of the transcription factor Dlx3, which is essential for Dlx3 transcriptional activity on Dspp as well as subsequent odontoblast differentiation and dentin formation.

RGS12 Drives Macrophage Activation and Osteoclastogenesis in Periodontitis

Periodontitis is a complex inflammatory disease affecting the supporting structures of teeth and is associated with systemic inflammatory disorders. Regulator of G-protein signaling 12 (RGS12), the largest protein in the RGS protein family, plays a crucial role in the development of inflammation and bone remodeling. However, the role and mechanism(s) by which RGS12 may regulate periodontitis have not been elucidated. Here, we showed that ablation of RGS12 in Mx1⁺ hematopoietic cells blocked bone loss in the ligature-induced periodontitis model, as evidenced morphometrically and by micro-computed tomography analysis of the alveolar bone. Moreover, hematopoietic cell-specific deletion of RGS12 inhibited osteoclast formation and activity as well as the production of inflammatory cytokines such as IL1β, IL6, and TNFα in the diseased periodontal tissue. In the in vitro experiments, we found that the overexpression of RGS12 promoted the reprogramming of macrophages to the proinflammatory M1 type, but not the anti-inflammatory M2 type, and enhanced the ability of macrophages for migration. Conversely, knockdown of RGS12 in macrophages inhibited the production of inflammatory cytokines and migration of macrophages in response to lipopolysaccharide stimulation. Our results demonstrate for the first time that inhibition of RGS12 in macrophages is a promising therapeutic target for the treatment of periodontitis.

Control of Phase Morphology of Binary Polymer Grafted Nanoparticle Blend Films via Direct Immersion Annealing

While the phase separation of binary mixtures of chemically different polymer-grafted nanoparticles (PGNPs) is observed to superficially resemble conventional polymer blends, the presence of a "soft" polymer-grafted layer on the inorganic core of these nanoparticles qualitatively alters the phase separation kinetics of these "nanoblends" from the typical pattern of behavior seen in polymer blends and other simple fluids. We investigate this system using a direct immersion annealing method (DIA) that allows for a facile tuning of the PGNPs phase boundary, phase separation kinetics, and the ultimate scale of phase separation after a sufficient "aging" time. In particular, by switching the DIA solvent composition from a selective one (which increases the interaction parameter according to Timmerman's rule) to an overall good solvent for both PGNP components, we can achieve rapid switchability between phase-separated and homogeneous states. Despite a relatively low and non-classical power-law coarsening exponent, the overall phase separation process is completed on a time scale on the order of a few minutes. Moreover, the roughness of the PGNP blend film saturates at a scale that is proportional to the in-plane phase separation pattern scale, as observed in previous blend and block copolymer film studies. The relatively low magnitude of the coarsening exponent n is attributed to a suppression of hydrodynamic interactions between the PGNPs. The DIA method provides a significant opportunity to control the phase separation morphology of PGNP blends by solution processing, and this method is expected to be quite useful in creating advanced materials.

Controlled drug release: On the evolution of physically entrapped drug inside the electrospun poly(lactic-co-glycolic acid) matrix

The drug loading and releasing properties of poly(lactic-co-glycolic acid) (PLGA) were approached with the application of neutron techniques. The neutron reflection (NR) study on the response of PLGA material to vapor and to bulk water revealed that the hydration of PLGA origins from the molecular compatibility between water and PLGA. Hydration is reversible with regard to the change in humidity and temperature. Capecitabine as drug was embedded in the electrospun PLGA fibers. Small angle neutron scattering (SANS) was able to disclose the domain of entrapped drug inside the fibers and trace its evolution over time when the electrospun membrane was incubated in D₂O buffer solution. The evolution of drug domains is discussed in terms of the concentration dependence, the temperature dependence, and the relevance between the drug diffusion inside the polymer matrix and the drug release out to the medium. It was observed that, at 20 °C the drug-related domains are relatively small (~ 100 Å) and relax extremely slow while at 37 °C the drug-related domains are relatively larger (~ 200 Å) and relax faster. These behaviors can be related to the glassy property of structural material. The transportation of drug through the polymer matrix relies on the global relaxation of PLGA chains. The variation of fiber diameter vs. incubation time was followed by ultra-small angle neutron scattering (USANS). The bi-phasic or tri-phasic release kinetics from a series of fibers with different drug loading (2%, 5%, 10%, 20%, 30%, 40%, 50%) were discussed based on the SANS and USANS discovery.

MicroRNA-596 is epigenetically inactivated and suppresses prostatic cancer cell growth and migration via regulating Wnt/β-catenin signaling

OBJECTIVES

Although studies have reported that miR-596 extensively participates in multiple cancer progression, the biological mechanisms and effects of miR-596 in prostatic cancer remain unclear. The literature is aimed to reveal the function and possible molecular mechanisms of miR-596 in prostatic cancer carcinogenesis.

MATERIALS AND METHODS

qRT-PCR was applied to examine miR-596 expression in prostatic cancer cell lines and samples, also methylation-specific PCR was used to detect the methylation status of the promoter CpG islands in prostatic cancer samples. Meanwhile, the tumor-related effects of miR-596 were detected via cell viability, clone formation assay, migration assay, flow cytometric and AO/EB assay. qRT-PCR and Western blots were applied to investigate the function of miR-596 on malignant behavior in prostatic cancer cells.

RESULTS

We found that miR-596 mRNA was decreased in prostatic cancer samples and cell lines. miR-596 mRNA level was also correlated to cancer stage, Gleason scores, while miR-596 promoter methylation was related to cancer tumor stage, Gleason score and preoperative PSA levels. miR-596 inhibited the cell growth and activity by causing cell apoptosis, and also suppressed the migration of prostatic cancer cells by revealing the epithelial-mesenchymal transition process. In addition, Western blot indicates that miR-596 overexpression deregulated Wnt/β-catenin signaling, by restraining phosphorylation levels of β-catenin and expression levels of downstream targets.

CONCLUSIONS

In summary, this research indicates that miR-596 overexpression could be potentially useful in the cell growth and migration of prostatic cancer and serves as a potential molecular marker in prostatic cancer.

Multi-layer structure of Inconel 625 coatings prepared by magnetron sputtering

The coating/substrate interface and oxide layers of the Inconel 625 film may have significant impacts on its material properties, especially the corrosion behavior of the film. However, since the interface and oxide layer can be very thin and experimental toolbox to characterize them is limited, the detailed vertical structure of Inconel 625 coatings remains poorly understood. In this study, a multi-layer structure in Inconel 625 film prepared by magnetron sputtering is revealed using X-ray reflectometry (XRR) and neutron reflectometry (NR) techniques. Thickness and major composition of each layer are obtained. The results indicate that there exists a ~2 nm-thick Cr-rich Inconel sublayer underneath the main Inconel 625 film. An oxide layer mainly consisting of NiO with thickness of ~2 nm is found on the surface of the main Inconel 625 film. In addition, we identified a ~2 Å contamination layer between sapphire substrate and Inconel film even after argon ion sputtering cleaning. We also found that the thickness of the main Inconel 625 film grows linearly with the deposition time, with thicknesses of other layers remaining constant. Our findings provide insight into the multi-layered structures of Inconel 625 coatings with atomic-scale spatial resolution and give directions for future study to improve the corrosion resistance of Inconel 625 coatings.

Salting Up and Salting Down of Bovine Serum Albumin Layers at the Air-Water Interface

The surface adsorption of bovine serum albumin in pure water and salted aqueous solutions was studied by neutron reflection. With the contrast match technique, the surface excess in null reflecting water as a function of the protein concentration was revealed. It is found that, in a concentration range from 1 ppm (parts per million, mg/L) to 1000 ppm, without salts, the surface excess shows a profound peak at around 20 ppm; with salts, the surface excess increases steadily with the protein concentration. When the surface excess at a specific protein concentration is viewed, the introduction of sodium chloride causes either a salting down effect (surface adsorption decline) or a salting up effect (surface adsorption increase), depending upon the protein concentration. The salting up effect is observed at the low (∼1 ppm) and high (∼1000 ppm) concentrations, and the salting down effect dominates the intermediate concentration range. The change in solution pH relative to the isoelectric point (PI) can act as a simple indicator for the salting up or salting down behavior. When the solution pH is shifted toward the PI by adding salts, surface adsorption enhances; when the solution pH is shifted away from the PI by adding salts, surface adsorption declines.

RGS12 Represses Oral Cancer via the Phosphorylation and SUMOylation of PTEN

Oral squamous cell carcinoma (OSCC) is the most common head and neck cancer characterized by aggressive local invasion and metastasis. The pathogenesis of OSCC is mainly due to the accumulation of genetic alterations in epithelial cells, but the underlying mechanism for its development remains unclear. Here, we found that the expression level of regulator of G protein signaling 12 (RGS12) was significantly reduced in human OSCC. To understand the role and mechanism of RGS12 in OSCC, we generated a novel RGS12 global knockout (CMV^Cre/+; RGS12^fl/fl) mouse model by crossing RGS12^fl/fl mice with CMV-Cre transgenic mice and then further induced the mice to develop OSCC by using 4-nitroquinoline 1-oxide (4NQO). Deletion of RGS12 exhibited aggressive OSCC in the tongue compared with the control RGS12^fl/fl mice. Knockdown of RGS12 in OSCC cells significantly increased cell proliferation and migration. Mechanistically, we found that RGS12 associated with phosphatase and tension homolog (PTEN) via the PDZ domain to upregulate the phosphorylation and SUMOylation of PTEN and then correspondingly inactivated the AKT/mTOR signaling pathway. To test the potential therapeutic effect of RGS12 on OSCC, we overexpressed RGS12 in OSCC cells and found a significant inhibition of cancer cell proliferation and migration. Moreover, subcutaneous inoculation of RGS12-overexpressed OSCC cells in NOD scid mice showed a significant reduction in tumor formation. Our findings reveal that RGS12 is an essential tumor suppressor and highlights RGS12 as a potential therapeutic target and prognostic biomarker of OSCC.

WWP2 Promotes Odontoblastic Differentiation by Monoubiquitinating KLF5

WW domain-containing E3 Ub-protein ligase 2 (WWP2) belongs to the homologous to E6AP C-terminus (HECT) E3 ligase family. It has been explored to regulate osteogenic differentiation, chondrogenesis, and palatogenesis. Odontoblasts are terminally differentiated mesenchymal cells, which contribute to dentin formation in tooth development. However, it remained unknown whether WWP2 participated in odontoblast differentiation. In this study, WWP2 was found to be expressed in mouse dental papilla cells (mDPCs), odontoblasts, and odontoblastic-induced mDPCs by immunohistochemistry and Western blotting. Besides, WWP2 expression was decreased in the cytoplasm but increased in the nuclei of differentiation-induced mDPCs. When Wwp2 was knocked down, the elevated expression of odontoblast marker genes (Dmp1 and Dspp) in mDPCs induced by differentiation medium was suppressed. Meanwhile, a decrease of alkaline phosphatase (ALP) activity was observed by ALP staining, and reduced formation of mineralized matrix nodules was demonstrated by Alizarin Red S staining. Overexpression of WWP2 presented opposite results to knockdown experiments, suggesting that WWP2 promoted odontoblastic differentiation of mDPCs. Further investigation found that WWP2 was coexpressed and interacted with KLF5 in the nuclei, leading to ubiquitination of KLF5. The PPPSY (PY2) motif of KLF5 was essential for its physical binding with WWP2. Also, cysteine 838 (Cys838) of WWP2 was the active site for ubiquitination of KLF5, which did not lead to proteolysis of KLF5. Then, KLF5 was confirmed to be monoubiquitinated and transactivated by WWP2, which promoted the expression of KLF5 downstream genes Dmp1 and Dspp. Deletion of the PY2 motif of KLF5 or mutation of Cys838 of WWP2 reduced the upregulation of Dmp1 and Dspp. Besides, lysine (K) residues K31, K52, K83, and K265 of KLF5 were verified to be crucial to WWP2-mediated KLF5 transactivation. Taken together, WWP2 promoted odontoblastic differentiation by monoubiquitinating KLF5.

Position-Dependent Diffusion Dynamics of Entangled Polymer Melts Nanoconfined by Parallel Immiscible Polymer Films

The morphological structure and dynamics of confined polymers adjacent to the polymer-polymer interface have a profound effect on determining the overall physical properties of polymer blends. We measured the diffusion dynamics of poly(methyl methacrylate) (PMMA) melts confined between polystyrene (PS) layers using neutron reflectivity. Combinations of various thicknesses of PMMA and deuterated PMMA (dPMMA) allowed us to experimentally reveal the nonmonotonic behavior of polymer mobility near the PS-PMMA interface. From the neutron reflectivity results, we found that the polymers adjacent to the immiscible polymer-polymer interface showed enhanced diffusion dynamics because of the repulsive interaction between PS and PMMA, whereas the polymer at local regions farther from the interface exhibited reduced dynamics. This is probably due to the nonspherical conformation of PMMA and spatial confinement near the PS-PMMA interface.

CDC6 is up-regulated and a poor prognostic signature in glioblastoma multiforme

PURPOSE

Glioblastoma multiforme (GBM) represents the most common and the most malignant type of brain tumor. Cell division cycle 6 (CDC6), a gene associated with DNA replication initiation, has been proven to be associated with the prognosis of multiple tumors. In this study, we aim to explore the association between CDC6 expression and GBM carcinogenesis and prognosis.

METHODS

CDC6 expression in normal cells and GBM cells was explored by analyzing TCGA dataset, as well as by RT-PCR and western blot methods. Survival analysis was performed by the Kaplan-Meier method. Multivariate Cox-regression analysis was adopted to estimate the independence of CDC6 as a GBM prognostic factor.

RESULTS AND CONCLUSIONS

Elevated CDC6 levels in GBM tumor tissues compared with those in normal brain tissues were illustrated by analyzing the gene expression profiles from TCGA dataset, and confirmed by RT-PCR and western blot assays in GBM tumor and normal human astrocyte cell lines. Kaplan-Meier analysis indicated the negative influence of high CDC6 expression on GBM overall survival (OS) probability and days to progression (D2P) after initial treatment, but not on days to recurrence (D2R) after initial treatment. Multivariate Cox regression analysis showed CDC6 as an independent signature marker gene for GBM prognosis. In addition, the combination of CDC6 mRNA expression and CpG island methylator phenotype (CIMP) could sensitively predict 3-year OS and D2P. In conclusion, our study uncovered the role of CDC6 in GBM carcinogenesis and prognosis for the first time, which could shed new light on GBM diagnosis and treatment.

Ultra-long high quality catalyst-free WO3 nanowires for fabricating high-performance visible photodetectors

This work presents a study on the controlled growth of WO₃ nanowires via chemical vapor deposition without catalyst, and their potential applications in visible photodetectors. The influence of growth conditions on the morphology of WO₃ nanowires is studied in order to understand the growth mechanism of WO₃ nanowires, and ultra-long (60 [Formula: see text], the longest one ever reported) WO₃ nanowires with a spindle shape are achieved by optimizing the growth conditions. It was found that the length of WO₃ nanowires increases from 15 [Formula: see text] to 60 [Formula: see text] with increasing the argon carrier gas flow rate from 30 sccm to 90 sccm, and then saturates with further increasing the argon carrier gas flow rate. However, the length of WO₃ nanowires reduces from 60 [Formula: see text] to 19 [Formula: see text] with increasing the tube inner pressure from 2.5 Torr to 3.5 Torr. The photoconductor detectors based on WO₃ single nanowires present excellent device performance with a responsivity as high as 19 A W^-1 at a bias of 0.1 V, a detectivity as high as 1.06 × 10¹¹ Jones, and a response (rising and decay) time as short as 8 ms under the illumination of a 404 nm laser. These results indicate the great potential of WO₃ nanowires for applications in fabricating high performance visible photodetectors.

Spatial Distribution of PEO-PPO-PEO Block Copolymer and PEO Homopolymer in Lipid Bilayers

Maintaining the integrity of cell membranes is indispensable for cellular viability. Poloxamer 188 (P188), a poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer with a number-average molecular weight of 8700 g/mol and containing 80% by mass PEO, protects cell membranes from various external injuries and has the potential to be used as a therapeutic agent in diverse applications. The membrane protection mechanism associated with P188 is intimately connected with how this block copolymer interacts with the lipid bilayer, the main component of a cell membrane. Here, we report the distribution of P188 in a model lipid bilayer comprising 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) using neutron reflectivity (NR) and atomic force microscopy (AFM). We also investigated the association of a PEO homopolymer (PEO8.4K; M_n = 8400 g/mol) that does not protect living cell membranes. These experiments were conducted following incubation of a 4.5 mmol/L polymer solution in a buffer that mimics physiological conditions with supported POPC bilayer membranes followed by washing with the aqueous medium. In contrast to previous reports, which dealt with P188 and PEO in salt-free solutions, both P188 and PEO8.4K penetrate into the inner portion of the lipid bilayer as revealed by NR, with approximately 30% by volume occupancy across the membrane without loss of bilayer structural integrity. These results indicate that PEO is the chemical moiety that principally drives P188 binding to bilayer membranes. No defects or phase-separated domains were observed in either P188- or PEO8.4K-incubated lipid bilayers when examined by AFM, indicating that polymer chains mingle homogeneously with lipid molecules in the bilayer. Remarkably, the breakthrough force required for penetration of the AFM tip through the bilayer membrane is unaffected by the presence of the large amount of P188 and PEO8.4K.

Mdm2 Promotes Odontoblast-like Differentiation by Ubiquitinating Dlx3 and p53

Dentin is an important structural component of the tooth. Odontoblast differentiation is an essential biological process that guarantees normal dentin formation, which is precisely regulated by various proteins. Murine double minute 2 (Mdm2) is an E3 ubiquitin ligase, and it plays a pivotal role in the differentiation of different cell types, such as osteoblasts and myoblasts. However, whether Mdm2 plays a role in odontoblast differentiation remains unknown. Here, we investigated the spatiotemporal expression of Mdm2 by immunostaining and found that Mdm2 was highly expressed in the odontoblasts and slightly in the dental papilla cells of mouse incisors and molars. Gene knockdown and overexpression experiments verified that Mdm2 promoted the odontoblast-like differentiation of mouse dental papilla cells (mDPCs). Intranuclear colocalization and physical interaction between Mdm2 and distal-less 3 (Dlx3), a transcription factor important for odontoblast differentiation, was found during the odontoblast-like differentiation of mDPCs by double immunofluorescence and immunoprecipitation. Mdm2 was proved to monoubiquitinate Dlx3, which enhanced the expression of Dlx3 target gene Dspp. In addition, p53, the canonical substrate of Mdm2, was validated to be also ubiquitinated but degraded by Mdm2 during the odontoblast-like differentiation of mDPCs. Gene knockdown experiments confirmed that p53 inhibited the odontoblast-like differentiation of mDPCs. p53 and Mdm2 double knockdown partially rescued the reduced odontoblast-like differentiation by knockdown of Mdm2 alone. Taken together, our study revealed that Mdm2 promoted the odontoblast-like differentiation of mDPCs by ubiquitinating both Dlx3 and p53. On one hand, the monoubiquitination of Dlx3 by Mdm2 led to upregulation of Dspp, which is a marker of the odontoblast differentiation. On the other hand, ubiquitination of p53 by Mdm2 resulted in its degradation, which eliminated the inhibitory effect of p53 on the odontoblast-like differentiation of mDPCs.

Enhanced Dynamics of Confined Polymers near the Immiscible Polymer-Polymer Interface: Neutron Reflectivity Studies

For polymer-blend films, local dynamics in confined polymer domains tend to differ from the bulk because of significant contributions from the polymer-polymer interface. Herein, we investigated the diffusion dynamics of entangled polymer thin films confined between different polymers in a direction perpendicular to the surface using neutron reflectivity. We found that a bilayer of poly(methyl methacrylate) (PMMA) and deuterated PMMA (dPMMA) sandwiched between polystyrene (PS) layers exhibited significant increase in mobility near the polymer-polymer interface with decreasing PMMA thickness. This indicates that the contribution of repulsive interactions at the immiscible polymer-polymer interface becomes more significant as the film thickness decreases. We also found that the interfacial roughness between PMMA and PS (28 Å at equilibrium) and soft confinement of PS layers did not significantly affect the change in the diffusion dynamics of the adjacent PMMA. This was evidenced by comparison with the diffusion results of multilayers with a flat interface (8 Å at equilibrium) between PMMA and hard PS by UV cross-linking.

The interplay of thermodynamics and kinetics: imparting hierarchical control over film formation of self-stratified blends

Spin casting has become an attractive method to fabricate polymer thin films found in organic electronic devices such as field-effect transistors, and light emitting diodes. Many studies have shown that altering spin casting parameters can improve device performance, which has been directly correlated to the degree of polymer alignment, crystallinity, and morphology of the thin film. To provide a thorough understanding of the balance of thermodynamic and kinetic factors that influence the stratification of polymer blend thin films, we monitor stratified polymer blend thin films developed from poly(3-hexylthiophene-2,5-diyl) and poly(methyl methacrylate) blends at controlled loading ratios, relative molecular weights, and casting speed. The structures of these thin films were characterized via neutron reflectivity, and the results show that at the fastest casting speed, polymer-polymer interactions and surface energy of the polymers in the blend dictate the final film structure, and at the slowest casting speed, there is less control over the film layering due to the polymer-polymer interactions, surface energy, and entropy simultaneously driving stratification. As well, the relative solubility limits of the polymers in the pre-deposition solution play a role in the stratification process at the slowest casting speed. These results broaden the current understanding of the relationship between spin casting conditions and vertical phase separation in polymer blend thin films and provide a foundation for improved rational design of polymer thin film fabrication processes to attain targeted stratification, and thus performance.

Unusually High Concentration of Alkyl Ammonium Hydroxide in the Cation-Hydroxide-Water Coadsorbed Layer on Pt

Interactions between a catalyst and electrolyte have paramount importance for the performance of electrochemical devices. Here, we present the cation-hydroxide-water coadsorption on the Pt surface by a rotating disk electrode and neutron reflectometry. The rotating disk electrode experiments show that the current density of Pt rapidly dropped at hydrogen oxidation potentials due to tetramethylammonium hydroxide (TMAOH)-water coadsorption. Subsequent neutron reflectometry in 0.1 M TMAOD/D₂O reveals that the thickness of the coadsorbed layer increased to 18 Å after 10.5 h exposure at 0.1 V vs reverse hydrogen electrode (RHE). The scattering length density analysis revealed that the TMAOD to water ratio in the coadsorbed layer was 4.5, which was significantly higher than the reportedly highest TMAOH concentration in aqueous solution. Finally, we discuss the potential impact of the coadsorbed layer on the performance and durability of alkaline membrane fuel cells, which sheds light on the material design of high-performance alkaline electrochemical devices.

Dewetting of Thin Polymer Films on Wrinkled Graphene Oxide Monolayers

We investigated the effect of the morphological structure of a graphene oxide (GO) monolayer on the dewetting dynamics of the upper polymer thin films. The Langmuir-Schaefer (LS) technique was used to prepare a wrinkled GO ( wrGO) structure with a root mean square (rms) roughness of 22.7 Å. The dewetting behavior of poly(methyl methacrylate) (PMMA) thin films on the wrGO monolayers was perfectly prevented, whereas the PMMA thin films on a flat GO monolayer were dewetted at 203 °C. This wrinkle effect of the GO can be also obtained when the GOs monolayers are intercalated to the PMMA/polystyrene (PS) interface. In this multilayer, the flat GO monolayer at the interface between the PS and PMMA layers was spontaneously roughened with rms roughness of 46.9 Å after annealing and also prohibited the dewetting behavior. From the results, we found that to improve the compatibility of polymer blends by adding the two-dimensional nanosheets, it is important to control the morphological structure of the sheets at the interface, along with manipulation of the GO-polymer interactions.

Response of a Permanently Charged Polyelectrolyte Brush to External Ions: The Aspects of Structure and Dynamics

Structure and dynamics inside permanently charged polyelectrolyte brushes, sodium polystyrene sulfonate brushes, during their response to the introduction of external ions (NaCl) are investigated by neutron reflectivity and dielectric spectroscopy. Neutron reflectivity measurements show that the segmental density of the inner part of the brushes decreases and that of the outer part increases when the salt level is tuned from the salt-free condition to a moderate level (<10^-2 M)-the brushes swell further compared with the salt-free condition. This is attributed to the breakup of the multiplets formed by dipole-dipole pairs, and by this process, the previously constrained chain segments by the multiplets are released. Dielectric spectroscopy discovers a giant dipole by the charge separation of the adsorbed counterions and the PSS^- chains, induced by electric field. The dynamics of the induced giant dipole is accelerated with the increase of external salt, as a result of the charge regularization by elevated salt level. At high-enough salt level, the screening effect reduces the electrostatic repulsion between the neighboring chains and makes the brushes shrink.

A cardioid oscillator with asymmetric time ratio for establishing CPG models

Nonlinear oscillators are usually utilized by bionic scientists for establishing central pattern generator models for imitating rhythmic motions by bionic scientists. In the natural word, many rhythmic motions possess asymmetric time ratios, which means that the forward and the backward motions of an oscillating process sustain different times within one period. In order to model rhythmic motions with asymmetric time ratios, nonlinear oscillators with asymmetric forward and backward trajectories within one period should be studied. In this paper, based on the property of the invariant set, a method to design the closed curve in the phase plane of a dynamic system as its limit cycle is proposed. Utilizing the proposed method and considering that a cardioid curve is a kind of asymmetrical closed curves, a cardioid oscillator with asymmetric time ratios is proposed and realized. Through making the derivation of the closed curve in the phase plane of a dynamic system equal to zero, the closed curve is designed as its limit cycle. Utilizing the proposed limit cycle design method and according to the global invariant set theory, a cardioid oscillator applying a cardioid curve as its limit cycle is achieved. On these bases, the numerical simulations are conducted for analyzing the behaviors of the cardioid oscillator. The example utilizing the established cardioid oscillator to simulate rhythmic motions of the hip joint of a human body in the sagittal plane is presented. The results of the numerical simulations indicate that, whatever the initial condition is and without any outside input, the proposed cardioid oscillator possesses the following properties: (1) The proposed cardioid oscillator is able to generate a series of periodic and anti-interference self-exciting trajectories, (2) the generated trajectories possess an asymmetric time ratio, and (3) the time ratio can be regulated by adjusting the oscillator's parameters. Furthermore, the comparison between the simulated trajectories by the established cardioid oscillator and the measured angle trajectories of the hip angle of a human body show that the proposed cardioid oscillator is fit for imitating the rhythmic motions of the hip of a human body with asymmetric time ratios.

ERAP1/ERAP2 and RUNX3 polymorphisms are not associated with ankylosing spondylitis susceptibility in Chinese Han

Previous studies show that endoplasmic reticulum‐associated aminopeptidase (ERAP1/ERAP2) and runt‐related transcription factor 3 (RUNX3) gene polymorphisms are associated with AS (ankylosing spondylitis) in European Caucasians. However, contradictory results were reported in different Asian populations. The purpose of this study was to determine whether eleven candidate single nucleotide polymorphisms (SNPs) in ERAP1/ERAP2 and six in RUNX3 genes confer susceptibility to AS with or without acute anterior uveitis (AAU) [AS⁺AAU⁺ or AS⁺AAU^–] in Chinese Han. Therefore, a case–control association study was performed in 882 AS⁺AAU^–, 884 AS⁺AAU⁺ and 1727 healthy controls. Genotyping was performed using the iPLEXGold genotyping assay. A meta‐analysis was performed to assess the association of polymorphisms of ERAP1 with AS susceptibility in Asian populations. No association was found between SNPs of ERAP1/ERAP2/RUNX3 and susceptibility of AS with or without AAU. A case–control study between patients with human leucocyte antigen HLA‐B27‐positive and healthy controls also failed to demonstrate an association of the tested SNP with AS with or without AAU. Moreover, a meta‐analysis showed that there was no association of rs30187, rs27037, rs27980, rs27434 and rs27582 in ERAP1 with AS in Chinese Han. Taken together, 17 SNPs in ERAP1/ERAP2 and RUNX3 genes did not confer disease susceptibility to AS in Chinese Han.

Structure-induced switching of interpolymer adhesion at a solid-polymer melt interface

Here we report a link between the interfacial structure and adhesive property of homopolymer chains physically adsorbed (i.e., via physisorption) onto solids. Polyethylene oxide (PEO) was used as a model and two different chain conformations of the adsorbed polymer were created on silicon substrates via the well-established Guiselin's approach: "flattened chains" which lie flat on the solid and are densely packed, and "loosely adsorbed polymer chains" which form bridges jointing up nearby empty sites on the solid surface and cover the flattened chains. We investigated the adhesion properties of the two different adsorbed chains using a custom-built adhesion testing device. Bilayers of a thick PEO overlayer on top of the flattened chains or loosely adsorbed chains were subjected to the adhesion test. The results revealed that the flattened chains do not show any adhesion even with the chemically identical free polymer on top, while the loosely adsorbed chains exhibit adhesion. Neutron reflectivity experiments corroborated that the difference in the interfacial adhesion is not attributed to the interfacial brodening at the free polymer-adsorbed polymer interface. Instead, coarse-grained molecular dynamics simulation results suggest that the tail parts of the loosely adsorbed chains act as "connector molecules", bridging the free chains and substrate surface and improving the interfacial adhesion. These findings not only shed light on the structure-property relationship at the interface, but also provide a novel approach for developing sticking/anti-sticking technologies through precise control of the interfacial polymer nanostructures.

Perpendicular Orientation of Diblock Copolymers Induced by Confinement between Graphene Oxide Sheets

We have studied an orientation structure of self-assembled block copolymers (dPS-b-PMMA) of deuterated polystyrene (dPS) and poly(methyl methacrylate) (PMMA) confined between graphene oxide (GO) surfaces. The results of combination techniques, such as neutron reflectivity, time-of-flight secondary-ion mass spectrometry, grazing-incidence small-angle X-ray scattering, and scanning electron microscopy, show that self-assembled domains of the block copolymers in thin films near the GO sheets are oriented perpendicular to the surface of the GO monolayers, in contrast to the horizontal lamellar structure of the copolymer thin film in the absence of the GO monolayers. This is due to the amphiphilic nature of the GO, which leads to a nonpreferential interaction of both dPS and PMMA blocks. Double-sided confinement with the GO monolayers further extends the ordering behavior of the dPS-b-PMMA thin films. Continuous vertical orientation of the block copolymer thin films is also obtained in the presence of alternating GO layers within thick copolymer films.

Film Confinement Induced "Jump-Percolation" Wetting Transition in Amphiphilic Block Copolymer Films

We report a first-order like sharp surface wettability transition with varying film thickness dependent morphology in cast films of an amphiphilic triblock copolymer. Films composed of poly(2-(N-ethylperfluorooctanesulfonamido) ethyl methyl acrylate), poly(FOSM), and poly(N,N'-dimethyl acrylamide), poly(DMA), with thickness (h) in the transition-range, 200 < h < 300 nm, exhibited an abrupt hydrophobic to hydrophilic dynamic water contact angle transition. After an induction time, t_i ≈ 40 to 180 s, water contact angle varied as θ_c ≈ 116° to 40° with an ultrafast contact angle decay time constant, [Formula: see text] ≈ -18°/s. This behavior is a result of competing heterogeneous and antagonistic effects of bumpy poly(DMA) wetting domains against a nonwetting planar poly(FOSM) background, with a "jump percolation" wetting transition when the poly(DMA) domain density reaches unity. Outside of this film thickness range, relatively shallow decreasing water contact angle gradients were observed with a monotonically increasing poly(DMA) domain area coverage with increasing film thickness in the overall range of 40 nm (hydrophobic, θ_c ≈ 118°) < h < 500 nm (hydrophilic, θ_c ≈ 8°). The optical diffuse reflectance properties of these rough surfaces exhibit an onset of diffuse reflectance maxima correlated to the transition morphology film thickness.

Insulin-like growth factor I reduces the occurrence of necrotizing enterocolitis by reducing inflammatory response and protecting intestinal mucosal barrier in neonatal rats model

OBJECTIVE

To observe the effect of enteral supplement of insulin-like growth factor I (IGF-1) on dynamic changes of TLR4, NF-κB, IL-6, SIgA and MUC2 in intestinal tissues of neonatal rats, and to investigate the protective effects and possible mechanisms of IGF-1 on necrotizing enterocolitis (NEC).

MATERIALS AND METHODS

Specific pathogen free (SPF) neonatal Sprague Dawley (SD) rats aged 3 days old were randomly divided into 3 groups, namely, normal control group, NEC model group and IGF-1 intervention group. In NEC group, the neonatal NEC rat models were established using artificial feeding, hypoxia and cold stimulation. In IGF-1 intervention group, the models were established by means of artificial feeding plus hypoxia and cold stimulation, and IGF-1 (22 ug/L) at a physiological concentration similar to the breast milk was added to milk replacer for intervention. The rats in the three groups were killed after the blood was collected from the heart at 24, 48 and 72 h, respectively, following the establishment of models; then, 3 cm of the terminal ilea were dissected and used for histopathological examination, RT-PCR and ELISA studies after hematoxylin and eosin (HE) staining.

RESULTS

Symptoms in IGF-1 intervention group were significantly relieved, and the incidence rate of NEC was lowered remarkably. In NEC model group, the peak expression of TLR4 mRNA occurred later than that of NF-κB mRNA and IL-6, and the expressions of TLR4 mRNA, NF-κB mRNA and IL-6 were decreased at 72 h after IGF-1 intervention. In NEC model group, the expression of MUC2 showed a transient decrease, the expression of SIgA was on the decline, but the expressions of MUC2 and SIgA were increased after IGF-1 intervention.

CONCLUSIONS

The enteral administration of IGF-1 at a physiological concentration can ameliorate the clinical symptoms in neonatal NEC rat models and decrease the occurrence rate. The possible mechanism is that IGF-1 down-regulates the TLR4 mRNA expression to inhibit the production of inflammatory mediators, and it up-regulates the expressions of MUC2 and SIgA to protect the mechanical and immuno-barrier functions of the intestinal mucous.

Modifying Surface Fluctuations of Polymer Melt Films with Substrate Modification

Deposition of a plasma polymerized film on a silicon substrate substantially changes the fluctuations on the surface of a sufficiently thin melt polystyrene (PS) film atop the substrate. Surface fluctuation relaxation times measured with X-ray photon correlation spectroscopy (XPCS) for ca. 4R_g thick melt films of 131 kg/mol linear PS on hydrogen-passivated silicon (H-Si) and on a plasma polymer modified silicon wafer can both be described using a hydrodynamic continuum theory (HCT) that assumes the film is characterized throughout its depth by the bulk viscosity. However, when the film thickness is reduced to ∼3R_g, confinement effects are evident. The surface fluctuations are slower than predicted using the HCT, and the confinement effect for the PS on H-Si is larger than that for the PS on the plasma polymerized film. This deviation is due to a difference in the thicknesses of the strongly adsorbed layers at the substrate which are impacted by the substrate surface energy.