Despite current treatment regimens, heart failure remains the leading cause of morbidity and mortality in the developed world due to the limited capacity of adult mammalian ventricular cardiomyocytes ...to divide and replace ventricular myocardium lost from ischaemia-induced infarct. Hence there is great interest to identify potential cellular sources and strategies to generate new ventricular myocardium. Past studies have shown that fish and amphibians and early postnatal mammalian ventricular cardiomyocytes can proliferate to help regenerate injured ventricles; however, recent studies have suggested that additional endogenous cellular sources may contribute to this overall ventricular regeneration. Here we have developed, in the zebrafish (Danio rerio), a combination of fluorescent reporter transgenes, genetic fate-mapping strategies and a ventricle-specific genetic ablation system to discover that differentiated atrial cardiomyocytes can transdifferentiate into ventricular cardiomyocytes to contribute to zebrafish cardiac ventricular regeneration. Using in vivo time-lapse and confocal imaging, we monitored the dynamic cellular events during atrial-to-ventricular cardiomyocyte transdifferentiation to define intermediate cardiac reprogramming stages. We observed that Notch signalling becomes activated in the atrial endocardium following ventricular ablation, and discovered that inhibiting Notch signalling blocked the atrial-to-ventricular transdifferentiation and cardiac regeneration. Overall, these studies not only provide evidence for the plasticity of cardiac lineages during myocardial injury, but more importantly reveal an abundant new potential cardiac resident cellular source for cardiac ventricular regeneration.
Cleft lip and/or cleft palate are the most common congenital craniofacial anomalies. Philtral ridge morphology is an important aesthetic component of unilateral cleft lip (UCL) repair. To this end, ...we have developed two techniques of philtral ridge reconstruction: (1) asymmetric mattress muscle sutures, and (2) overlapping mattress muscle sutures. The objective of this retrospective cohort study was to compare their outcomes in UCL repairs. Group I patients (n=30) underwent UCL repair before August 2003, including philtral ridge reconstruction by asymmetric mattress muscle sutures. Group II patients (n=30) underwent UCL repair after August 2003, including philtral ridge reconstruction by overlapping mattress muscle sutures. Philtral morphology was evaluated by ultrasonographic and three-dimensional photographic measurements, examining cleft side philtral projection and philtral ridge symmetry. These demonstrated that group II patients had better philtral column symmetry and projection on the cleft side when compared to group I. Overlapping mattress muscle sutures produced better philtral morphology in UCL repairs than asymmetric mattress muscle sutures.
A stable occlusion at the time of surgery is considered important for post-surgical stability after orthognathic surgery. The aim of this study was to determine whether skeletal stability after ...bimaxillary surgery using a surgery-first approach for skeletal class III deformity is related to the surgical occlusal contact or surgical change. Forty-two adult patients with a skeletal class III deformity corrected by Le Fort I osteotomy and bilateral sagittal split osteotomy with a surgery-first approach were studied. Dental models were set and used to measure the surgical occlusal contact, including contact distribution, contact number, and contact area. Cone beam computed tomography was used to measure the surgical change (amount and rotation) and post-surgical skeletal stability. The relationship between skeletal stability and surgical occlusal contact or surgical change was evaluated. No relationship was found between maxillary or mandibular stability and surgical occlusal contact. However, a significant relationship was found between maxillary and mandibular stability and the amount and rotation of surgical change. The results suggest that in the surgical-orthodontic correction of skeletal class III deformity with a surgery-first approach, the post-surgical skeletal stability is not related to the surgical occlusal contact but is related to the surgical change.
To compare the accuracy of three-dimensional (3D) high-resolution (HR) magnetic resonance imaging (MRI), time-of-flight magnetic resonance angiography (TOF-MRA), contrast-enhanced magnetic resonance ...angiography (CE-MRA), and digital subtraction angiography (DSA) in measuring the degree of stenosis in intracranial atherosclerosis.
All patients with intracranial artery ischaemic events underwent HR-MRI, TOF-MRA, and CE-MRA analysis, and some of these patients underwent DSA examination. The correlation between different methods for measuring the degree of lumen stenosis was analysed. The accuracy of HR-MRI, TOF-MRA, and CE-MRA was evaluated and compared with that of DSA.
A total of 189 arterial stenoses were identified in 93 patients. Of these, 72 patients with 142 arterial stenoses underwent DSA examination. A very strong correlation between HR-MRI and CE-MRA measurements was shown (r=0.839, p<0.0001). The correlation between HR-MRI and TOF-MRA measurements was strong (r=0.720, p<0.0001). A very strong correlation between HR-MRI and DSA measurements was found (r=0.864, p<0.0001), and a similar correlation was observed between CE-MRA, and DSA measurements (r=0.843, p<0.0001). The correlation between TOF-MRA and DSA measurements was strong (r=0.686, p<0.0001). There was substantial agreement between HR-MRI and DSA measurements (K = 0.772) and between CE-MRA, and DSA measurements (K = 0.734) that was slightly higher than the agreement between TOF-MRA and DSA measurements (K = 0.636).
HR-MRI can accurately measure stenosis (especially for moderate and severe stenosis) in intracranial atherosclerosis by direct visualisation of the vessel lumen and steno-occlusive plaque.
•Very strong correlation between 3D HR-MRI and CE-MRA in measuring lumen stenosis.•Strong correlation between 3D HR-MRI and TOF-MRA in measuring lumen stenosis.•Substantial agreement between 3D HR-MRI and DSA for assessing lumen stenosis degree.•3D HR-MRI can accurately assess the degree of intracranial atherosclerotic stenosis.
Oxide-dispersion-strengthened steels are the most promising structural materials for next-generation nuclear energy systems because of their excellent resistance to both irradiation damage and ...high-temperature creep. Although it has been known for a decade that the extraordinary mechanical properties of oxide-dispersion-strengthened steels originate from highly stabilized oxide nanoclusters with a size smaller than 5 nm, the structure of these nanoclusters has not been clarified and remains as one of the most important scientific issues in nuclear materials research. Here we report the atomic-scale characterization of the oxide nanoclusters using state-of-the-art Cs-corrected transmission electron microscopy. This study provides compelling evidence that the nanoclusters have a defective NaCl structure with a high lattice coherency with the bcc steel matrix. Plenty of point defects as well as strong structural affinity of nanoclusters with the steel matrix seem to be the most important reasons for the unusual stability of the clusters at high temperatures and in intensive neutron irradiation fields.
•TiB2 coating is fabricated on 304SS bipolar plates by the HEMAA technique.•TiB2 coating is effective for improving corrosion resistance and conductivity of bipolar plates.•Corrosion is evaluated in ...both the anodic and cathodic environments of PEMFCs.•TiB2-coated 304SS maintains effective conductivity after corrosion test.
Titanium diboride (TiB2) coatings are fabricated on 304 stainless steel bipolar plates using a cost-effective, high-energy micro-arc alloying technique to enhance their corrosion resistance and conductivity. Both the coated and bare bipolar plates are electrochemically tested in solutions to simulate the cathode and anode working environments of the proton exchange membrane fuel cell, namely 0.3 M H2SO4 and 2 ppm HF with air or hydrogen gas bubbled through. It is found that the compact TiB2 coating with metallurgical bonding to the substrate obviously increases the substrate corrosion potential in both the cathode and anode. Meanwhile, the coating significantly decreases the corresponding corrosion current density of the cathode and anode by three to four orders of magnitude compared to the substrate. The impedance and open circuit potential of the TiB2-coated steels during long-term immersion are significantly higher than those of the substrate. Furthermore, the contact resistance of the TiB2-coated sample after corrosion remains 19 mΩ cm2, which is lower than that of the bare steel. Therefore, TiB2 coating is demonstrated as a promising alternative for enhancing the corrosion resistance and conductivity of bipolar plates, owing to its high chemical stability and effective conductivity.
An array of ZnO/Fe2O3 core-shell nanowires (NW) for the highly efficient absorption of light and carrier collection is developed for use in photoelectrochemical (PEC) water-splitting. The oriented NW ...architecture favors physical matching, providing a direct electron conduction pathway and reducing the diffusion length of photogenerated holes. This work involves a combination of spectral imaging, spectromicroscopy and in situ x-ray absorption spectroscopy; spectra are obtained under operando conditions. Direct investigation of oriented nanowires using polarization-dependent x-ray spectromicroscopy enables the determination of the relationship between anisotropic electronic orbitals and charge carrier water-splitting efficiency. The results of O K-edge STXM demonstrated that the ZnO/Fe2O3 core-shell NW exhibits strong anisotropy and thus provides higher electron-hole transport efficiency than bare ZnO. In situ XAS revealed that interfacial charge transfer between Fe 3d and Zn 4p states enhances the photoelectrochemical reaction in the ZnO/Fe2O3 core-shell NW. The photogenerated electrons of Fe2O3 are transferred from Fe 3d states to the Zn 4p state under photoelectrochemical conditions.
Objectives
This study correlated immunohistochemical studies with fluorodeoxyglucose (FDG) uptake on positron emission tomography–computed tomography (PET–CT) and identified prognostic factors for ...radiotherapy (RT)‐based treatment outcomes in patients with squamous cell carcinoma of the oropharynx and hypopharynx.
Methods
Genomic data from pre‐treatment biopsy specimens (Glut1, CAIX, VEGF, HIF‐1α, EGFR, Ki‐67, Bcl‐2, CLAUDIN‐4, YAP‐1, c‐Met and p16) of 76 patients were analysed using tissue microarrays. FDG uptake was evaluated using the maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis (TLG).
Results
The overexpression of Glut1 positively associated with increased values of the SUVmax, MTV and TLG, whereas VEGF and HIF‐1α expression with the MTV and TLG, respectively. A VEGF immunoreactive score (IRS) >2 (P = 0.001, hazard ratio HR = 3.94) and an MTV defined by an SUV of 2.5 (MTV2.5) >14.5 mL (P = 0.004, HR = 3.31) were prognostic factors for low cause‐specific survival, whereas a VEGF IRS >2 (P = 0.02, HR = 2.83) for low primary relapse‐free survival.
Conclusion
The overexpression of Glut1, VEGF and HIF‐1α associated with increased FDG uptake. For patients with pharyngeal cancer requiring RT, the treatment outcome can be stratified by VEGF and MTV2.5.
Protein acetylation is conserved across phylogeny and has been recognized as one of the most prominent post-translational modifications since its discovery nearly 60 years ago. Histone acetylation is ...an active mark characteristic of open chromatin, but acetylation on specific lysine residues and histone variants occurs in different biological contexts and can confer various outcomes. The significance of acetylation events is indicated by the associations of lysine acetyltransferases, deacetylases, and acetyl-lysine readers with developmental disorders and pathologies. Recent advances have uncovered new roles of acetylation regulators in chromatin-centric events, which emphasize the complexity of these functional networks. In this review, we discuss mechanisms and dynamics of acetylation in chromatin organization and DNA-templated processes, including gene transcription and DNA repair and replication.
Chen et al. dive into the mechanisms and dynamics of protein acetylation in chromatin organization and DNA-templated processes, including gene transcription and DNA repair and replication. Newly discovered roles of acetylation regulators in chromatin-centric events have implications for human disease.
PDF
