Scalable ultrastrong MXene films with superior osteogenesis.

Titanium carbide MXene flakes have promising applications in aerospace, flexible electronic devices and biomedicine owing to their superior mechanical properties1 and electrical conductivity2 and good photothermal conversion3, biocompatibility4 and osteoinductivity5. It is highly desired yet very challenging to assemble MXene flakes into macroscopic high-performance materials in a scalable manner. Here we demonstrate a scalable strategy to fabricate high-performance MXene films by roll-to-roll-assisted blade coating (RBC) integrated with sequential bridging, providing good photothermal conversion and osteogenesis efficiency under near-infrared irradiation. MXene flakes were first bridged with silk sericin by hydrogen bonding and then assembled into macroscopic films using a continuous RBC process, followed by ionic bridging to freeze their aligned structure. The resultant large-scale MXene films with strong interlayer interactions are highly aligned and densified, exhibiting high tensile strength (755 MPa), toughness (17.4 MJ m-3) and electromagnetic interference (EMI) shielding capacity (78,000 dB cm2 g-1), as well as good ambient stability, photothermal conversion and bone regeneration performance. The proposed strategy not only paves a feasible way for realizing the practical applications of MXene in the fields of flexible EMI shielding materials and bone tissue engineering but also provides an avenue for the high-performance and scalable assembly of other two-dimensional flakes.

Multi-Omics Reveals the Genetic and Metabolomic Architecture of Chirality Directed Stem Cell Lineage Diversification.

Chirality-directed stem-cell-fate determination involves coordinated transcriptional and metabolomics programming that is only partially understood. Here, using high-throughput transcriptional-metabolic profiling and pipeline network analysis, the molecular architecture of chirality-guided mesenchymal stem cell lineage diversification is revealed. A total of 4769 genes and 250 metabolites are identified that are significantly biased by the biomimetic chiral extracellular microenvironment (ECM). Chirality-dependent energetic metabolism analysis has revealed that glycolysis is preferred during left-handed ECM-facilitated osteogenic differentiation, whereas oxidative phosphorylation is favored during right-handed ECM-promoted adipogenic differentiation. Stereo-specificity in the global metabolite landscape is also demonstrated, in which amino acids are enriched in left-handed ECM, while ether lipids and nucleotides are enriched in right-handed ECM. Furthermore, chirality-ordered transcriptomic-metabolic regulatory networks are established, which address the role of positive feedback loops between key genes and central metabolites in driving lineage diversification. The highly integrated genotype-phenotype picture of stereochemical selectivity would provide the fundamental principle of regenerative material design.

Role of cell rearrangement and related signaling pathways in the dynamic process of tip cell selection.

Angiogenesis is a complex, highly-coordinated and multi-step process of new blood vessel formation from pre-existing blood vessels. When initiated, the sprouting process is spearheaded by the specialized endothelial cells (ECs) known as tip cells, which guide the organization of accompanying stalk cells and determine the function and morphology of the finally-formed blood vessels. Recent studies indicate that the orchestration and coordination of angiogenesis involve dynamic tip cell selection, which is the competitive selection of cells to lead the angiogenic sprouts. Therefore, this review attempt to summarize the underlying mechanisms involved in tip cell specification in a dynamic manner to enable readers to gain a systemic and overall understanding of tip cell formation, involving cooperative interaction of cell rearrangement with Notch and YAP/TAZ signaling. Various mechanical and chemical signaling cues are integrated to ensure the right number of cells at the right place during angiogenesis, thereby precisely orchestrating morphogenic functions that ensure correct patterning of blood vessels. Video Abstract.

[Bionic design, preparation and clinical translation of oral hard tissue restorative materials].

Oral diseases concern almost every individual and are a serious health risk to the population. The restorative treatment of tooth and jaw defects is an important means to achieve oral function and support the appearance of the contour. Based on the principle of "learning from the nature", Deng Xuliang's group of Peking University School and Hospital of Stomatology has proposed a new concept of "microstructural biomimetic design and tissue adaptation of tooth/jaw materials" to address the worldwide problems of difficulty in treating dentine hypersensitivity, poor prognosis of restoration of tooth defects, and vertical bone augmentation of alveolar bone after tooth loss. The group has broken through the bottleneck of multi-stage biomimetic technology from the design of microscopic features to the enhancement of macroscopic effects, and invented key technologies such as crystalline/amorphous multi-level assembly, ion-transportation blocking, and multi-physical properties of the micro-environment reconstruction, etc. The group also pioneered the cationic-hydrogel desensitizer, digital stump and core integrated restorations, and developed new crown and bridge restorative materials, gradient functionalisation guided tissue regeneration membrane, and electrically responsive alveolar bone augmentation restorative membranes, etc. These products have established new clinical strategies for tooth/jaw defect repair and achieved innovative results. In conclusion, the research results of our group have strongly supported the theoretical improvement of stomatology, developed the technical system of oral hard tissue restoration, innovated the clinical treatment strategy, and led the progress of the stomatology industry.

Sub-Nanosheet Induced Inverse Growth of Negative Valency Au Clusters for Tumor Treatment by Enhanced Oxidative Stress.

Cluster aggregation states are thermodynamically favored at the subnanoscale, for which an inverse growth from nanoparticles to clusters may be realized on subnanometer supports. Herein, we develop Au-polyoxometalate-layered double hydroxide (Au-POM-LDH) sub-1 nm nanosheets (Sub-APL) based on the above strategy, where sub-1 nm Au clusters with negative valence are generated by the in situ disintegration of Au nanoparticles on POM-LDH supports. Sub-1 nm Au clusters with ultrahigh surface atom ratios exhibit remarkable efficiency for glutathione (GSH) depletion. The closely connected sub-1 nm Au with negative valence and POM hetero-units can promote the separation of hole-electrons, resulting in the enhanced reactive oxygen species (ROS) generation under ultrasound (US). Besides, the reversible redox of Mo in POM is able to deplete GSH and trigger chemodynamic therapy (CDT) simultaneously, further enhancing the oxidative stress. Consequently, the Sub-APL present 2-fold ROS generation under US and 7-fold GSH depletion compared to the discrete Au and POM-LDH mixture. Therefore, the serious imbalance of redox in the TME caused by the sharp increase of ROS and rapid decrease of GSH leads to death of tumor ultimately.

Chirality and Curvature on Protein Adsorption and Osteogenesis.

Here we designed enantiomeric lipid-mimetic glutamic acid derivatives (L/D-UG) and investigated their self-assembled chiral nanostructures' interaction with the protein adsorption as well as the osteogenesis. It was found that L or D-UG molecules can self-assemble into vesicle bilayers and two-dimensional (2D) nanocrystals via a kinetic and thermodynamic control, respectively. These chiral vesicles and 2D crystals showed differentiated adsorption of proteins, determined by their curvature and chirality. Specifically, fibronectin constituted by L-amino acids adsorbed preferentially on L-UG 2D crystal in a semi-random pattern and L-2D nanocrystal show as the most effective structures to promote bone regeneration. The controlled vesicle and 2D crystal assemblies with different chirality and curvature helps to clarify their determine roles in protein adsorption and osteogenesis.

Hypoxia-Triggered Bioreduction of Poly(N-oxide)-Drug Conjugates Enhances Tumor Penetration and Antitumor Efficacy.

PEGylation prolongs the blood circulation time of drugs; however, it simultaneously reduces the tumor penetration of drugs due to the nonfouling function and bulky hydrodynamic volume of PEG, leading to unsatisfactory outcomes in the treatment of solid tumors. Herein, we report the in situ growth of a bioreducible polymer of poly(N-oxide) from an important protein drug of interferon alpha (IFN) to generate site-specific IFN-poly(N-oxide) conjugates with higher bioactivity than a clinically used PEGylated IFN of PEGASYS. An IFN-poly(N-oxide) conjugate is screened out to have a circulating half-life as long as 51 h, which is similar to that of PEGASYS but 96-fold greater than that of IFN. However, the conjugate greatly outperforms PEGASYS and IFN in tumor penetration and antitumor efficacy in mice bearing melanoma. This enhanced tumor penetration is ascribed to the adsorption-mediated transcytosis of the conjugate whose poly(N-oxide) is biologically reduced into poly(tertiary amine), under hypoxia, which can be further protonated in the acidic tumor microenvironment. These novel findings demonstrate that poly(N-oxide)s are not only long-circulating but also bioreducible under hypoxia and are of great promise as next-generation carriers to deliver drugs into the interior of solid tumors to enhance their antitumor efficacy.

Graphene oxide bulk material reinforced by heterophase platelets with multiscale interface crosslinking.

Graphene oxide (GO) and reduced GO possess robust mechanical, electrical and chemical properties. Their nanocomposites have been extensively explored for applications in diverse fields. However, due to the high flexibility and weak interlayer interactions of GO nanosheets, the flexural mechanical properties of GO-based composites, especially in bulk materials, are largely constrained, which hinders their performance in practical applications. Here, inspired by the amorphous/crystalline feature of the heterophase within nacreous platelets, we present a centimetre-sized, GO-based bulk material consisting of building blocks of GO and amorphous/crystalline leaf-like MnO2 hexagon nanosheets adhered together with polymer-based crosslinkers. These building blocks are stacked and hot-pressed with further crosslinking between the layers to form a GO/MnO2-based layered (GML) bulk material. The resultant GML bulk material exhibits a flexural strength of 231.2 MPa. Moreover, the material exhibits sufficient fracture toughness and strong impact resistance while being light in weight. Experimental and numerical analyses indicate that the ordered heterophase structure and synergetic crosslinking interactions across multiscale interfaces lead to the superior mechanical properties of the material. These results are expected to provide insights into the design of structural materials and potential applications of high-performance GO-based bulk materials in aerospace, biomedicine and electronics.

Association between circulating 25-hydroxyvitamin D metabolites and periodontitis: Results from the NHANES 2009-2012 and Mendelian randomization study.

AIM: This study sought to investigate associations of 25-hydroxyvitamin D (25(OH)D) metabolites with periodontitis and to assess causality using Mendelian randomization (MR). MATERIALS AND METHODS: This study included 7246 participants of the National Health and Nutrition Examination Survey, 2009-2012. The association of periodontitis with 25(OH)D metabolites was assessed using multivariable logistic regression analysis. Two-sample MR for 25(OH)D, 25(OH)D3 , and C3-epi-25(OH)D3 with periodontitis (n = 17,353 cases/28,210 controls) was conducted. The principal analysis employed the inverse-variance-weighted (IVW) approach. We controlled for horizontal pleiotropy using five additional methods. RESULTS: Based on the observational study, each 1-point increase in standard deviation of 25(OH)D lowered the risk of periodontitis by 15% (OR = 0.85, 95% confidence interval [CI]: 0.78-0.93, p = .006) after multivariable adjustment. A similar relationship was observed between 25(OH)D3 and periodontitis (OR = 0.88, 95% CI: 0.80-0.97, p = .031). Furthermore, a potential non-linear association was found between periodontitis and both 25(OH)D and 25(OH)D3 . However, C3-epi-25(OH)D3 was not found to be associated with periodontitis risk. IVW-MR showed that periodontitis risk was not significantly associated with genetically increased levels of 25(OH)D (OR = 1.02, 95% CI: 0.90-1.16, p = .732), 25(OH)D3 (OR = 1.04, 95% CI: 0.93-1.17, p = .472), or C3-epi-25(OH)D3 (OR = 1.11, 95% CI: 0.87-1.41, p = .400). The pleiotropy-robust MR approaches yielded similar results after we had eliminated the variants with horizontal pleiotropy risk. CONCLUSIONS: Cross-sectional observational analysis identified significant relationships between periodontitis with 25(OH)D metabolites, while findings based on MR study did not support a causal role.

Heavy metals in drinking water and periodontitis: evidence from the national oral health survey from China.

BACKGROUND: Periodontitis has become an increasingly important public health issue, coupled with a high economic burden for prevention and treatment. Exposure to essential trace heavy metals has been associated with various diseases; however, the relationships between essential trace heavy metals and periodontitis remain inconclusive. OBJECTIVES: To investigate the association between essential trace heavy metals in tap water and periodontitis in a nationally representative sample in China. METHODS: We conducted a nationwide study including 1348 participants from the Fourth National Oral Health Survey in the 2015-2016 period. The trace heavy metals concentration was measured in the local pipeline terminal tap water. Periodontitis was diagnosed according to the classification scheme proposed at the 2018 world workshop on the classification of periodontal and peri-implant diseases and conditions. We used weighted multivariable logistic regression to estimate the association between essential trace heavy metals and the risk of periodontitis. We additionally used spline analysis to explore the possible nonlinear dose-response associations. RESULTS: Periodontitis patients were exposed to higher concentrations of essential trace heavy metals. In adjusted models, for 1 SD increase in the concentration of iron, manganese, and copper in tap water, the risk of periodontitis increased by 30% (OR: 1.30, 95%CI: 1.12-1.50), 20% (OR: 1.20, 95%CI: 1.03-1.41), and 20% (OR: 1.20, 95%CI: 1.04-1.39), respectively. Stratified analyses demonstrated that the associations between essential trace heavy metals and periodontitis were higher in females, elders, and rural residents. Spline analysis revealed nonlinear exposure-response relationships between periodontitis and exposure to iron, manganese, and copper in tap water. CONCLUSIONS: Exposures to essential trace heavy metals in drinking water were associated with greater odds of periodontitis. Given the growing burden of periodontitis, our study sheds light on tailored public health policies for improving drinking water standards to alleviate periodontitis impairment.

N-Terminal Lysozyme Conjugation to a Cationic Polymer Enhances Antimicrobial Activity and Overcomes Antimicrobial Resistance.

Microbial resistance to antibiotics is one of the greatest global healthcare challenges. There is an urgent need to develop effective strategies to overcome antimicrobial resistance. We, herein, report photoinduced in situ growth of a cationic polymer from the N-terminus of lysozyme. The attachment of the cationic polymer improves the proteolytic and thermal stability of lysozyme. Notably, the conjugate can efficiently overcome lysozyme resistance in Gram-positive bacteria and antibiotics-resistance in Gram-negative bacteria, which may be ascribed to the synergistic interactions of lysozyme and the cationic polymer with the bacteria to disrupt their cell membranes. In a rat periodontitis model, the lysozyme-polymer conjugate not only greatly outperforms lysozyme in therapeutic efficacy but also is superior to minocycline hydrochloride, which is the gold standard for periodontitis therapy. These findings may provide an efficient strategy to dramatically enhance the antimicrobial activities of lysozyme and pave a way to overcome antimicrobial resistance.

Regulating the Mechanical and Optical Properties of Polymer-based Nanocomposites by Sub-Nanowires.

Sub-nanowires (SNWs) exhibit great potential applications in nanocomposites owing to their high specific surface area, high flexibility, and similarity to polymer chains in dimension, which are a good entry point to bridge inorganic materials and polymer materials. Herein, we synthesized hydroxyapatite sub-nanowires (HAP SNWs) and engineered hydroxyapatite sub-nanowires/polyimide (HSP) gels and films by simple mixing of HAP SNWs and polyimide (PI). Benefiting from the interactions between HAP SNWs and PI, these nanocomposites were a continuous hybrid network. As the increase of HAP SNWs contents, the viscosity and modulus of HSP gels were greatly improved by one or two orders of magnitude compared with PI gel. HSP films not only maintained high transparency but also gained high haze, as well as exhibited enhanced Young's modulus. Thus, both HSP gels and films developed in this work are promising for various applications in coatings and high-performance films.

Thermosensitive Polymer Conjugated Prodrug-Activating Enzyme with Enhanced Tumor Retention and Antitumor Efficacy.

Enzyme-activated prodrug therapy has emerged as an effective strategy for cancer therapy. However, the inefficient delivery of prodrug-activating enzymes into tumor tissues leads to unsatisfactory antitumor efficacy and undesirable toxicity to normal tissues. Herein, we report in situ growth of a thermosensitive polymer of poly(diethylene glycol) methyl ether methacrylate (PDEGMA) from horseradish peroxidase (HRP) to yield a HRP-PDEGMA conjugate with well-retained activity as compared to HRP. The conjugate shows a sharp phase transition behavior with a lower critical solution temperature of 23 °C. The conjugate catalyzes the conversion of non-cytotoxic indole-3-acetic acid (IAA) into cytotoxic species for killing tumor cells. Notably, the PDEGMA conjugation not only increases the stability and cellular uptake of HRP but also prolongs the tumor retention time of HRP upon intratumoral injection. As a result, in mice bearing melanoma, the conjugate inhibits the growth of melanoma much more efficiently than HRP. These results demonstrate that the thermosensitive polymer conjugation of an enzyme is an effective strategy that can enhance the antitumor efficacy of an enzyme-activated prodrug.

Modulating the Schottky barrier of MXenes/2D SiC contacts via functional groups and biaxial strain: a first-principles study.

Two-dimensional (2D) graphene-like SiC has attracted intense interest recently due to its unique electrical and physical properties. In implementing 2D semiconductors in device applications, one of the main challenges so far has been the formation of a high-quality Schottky barrier owing to the strong Fermi level pinning (FLP) at the interface of traditional metal-2D semiconductor contacts. In this paper, the 2D MXenes Ti3C2T2 (T = F, O, OH) are proposed to serve as electrodes for 2D SiC. The structural and barrier properties of the Ti3C2T2/SiC contacts were systematically investigated based on first-principles calculations combined with the GGA-PBE and HSE06 functionals. It is found that Ti3C2T2 can be bonded with 2D SiC by van der Waals (vdW) interactions. Weak FLP is exhibited at Ti3C2T2/SiC vdW contacts. The type of contact can be tuned by changing the functional T group of Ti3C2T2. Ti3C2F2/SiC and Ti3C2O2/SiC contacts exhibit a p-type Schottky contact and p-type Ohmic contact, respectively, whereas an n-type Ohmic contact occurs in the Ti3C2(OH)2/SiC contact. In addition, the calculated tunneling possibility (TB) is ∼20% between Ti3C2T2 and SiC, indicating weak bonding at the Ti3C2T2/SiC vdW junctions. Furthermore, the Schottky barrier height and TB of the Ti3C2(OH)2/SiC contacts can be modulated via the biaxial strain. The controllable contact type and barrier in Ti3C2T2/SiC contacts provide guidelines for developing high-performance 2D SiC optoelectronic and electronic devices.

An overview of signaling pathways regulating YAP/TAZ activity.

YAP and TAZ are ubiquitously expressed homologous proteins originally identified as penultimate effectors of the Hippo signaling pathway, which plays a key role in maintaining mammalian tissue/organ size. Presently, it is known that YAP/TAZ also interact with various non-Hippo signaling pathways, and have diverse roles in multiple biological processes, including cell proliferation, tissue regeneration, cell lineage fate determination, tumorigenesis, and mechanosensing. In this review, we first examine the various microenvironmental cues and signaling pathways that regulate YAP/TAZ activation, through the Hippo and non-Hippo signaling pathways. This is followed by a brief summary of the interactions of YAP/TAZ with TEAD1-4 and a diverse array of other non-TEAD transcription factors. Finally, we offer a critical perspective on how increasing knowledge of the regulatory mechanisms of YAP/TAZ signaling might open the door to novel therapeutic applications in the interrelated fields of biomaterials, tissue engineering, regenerative medicine and synthetic biology.

Age and gender differences in ACE2 and TMPRSS2 expressions in oral epithelial cells.

BACKGROUND: SARS-CoV-2, which has brought a huge negative impact on the world since the end of 2019, is reported to invade cells using the spike (S) protein to bind to angiotensin-converting enzyme II (ACE2) receptors on human cells while the transmembrane protease serine 2 (TMPRSS2) is the key protease that activates the S protein, which greatly facilitates the entry of SARS-CoV-2 into target cells. In our previous study, it was observed that the positive rate of SARS-CoV-2 nucleic acids in saliva was higher in male and the elderly COVID-19 patients, suggesting that the susceptibility of oral tissues to SARS-CoV-2 may be related to gender and age. This research aimed to further investigate the SARS-CoV-2 susceptibility in oral tissues and influencing factors from the perspective of ACE2 and TMPRSS2, which were two proteins closely associated with SARS-CoV-2 infection. METHODS: Immunofluorescence was used to find the localization of ACE2 and TMPRSS2 in oral mucosal tissues. Transcriptomic sequencing data of several datasets were then collected to analysis the relationship between the expressions of ACE2 and TMPRSS2 with the age and gender of patients. Furthermore, oral tissues from patients with different ages and genders were collected. Immunohistochemistry staining, qRT-PCR and western blot were performed to explore the relationship between expression levels of ACE2 and TMPRSS2 and patient age as well as gender. RESULTS: The results showed that the two proteins were able to be co-expressed in the epithelial cells of oral tissues, and their expression levels were higher in the relatively elderly group than those in relatively younger group. Male oral epithelial cells exhibited higher level of TMPRSS2. CONCLUSIONS: Our findings comprehensively confirmed the existence of ACE2 and TMPRSS2 in oral tissues and clarify the relationship between the expression levels with human age and gender for the first time, providing evidence for possible entry routes of SARS-CoV-2 and the influencing factors of SARS-CoV-2 colonization in oral cavity. Thus, the oral mucosa might be at potential risk of infection by SARS-CoV-2, especially in male or elderly patients. Using saliva to detect the nucleic acids of SARS-CoV-2 may be more accurate for elder male COVID-19 patients.

Electromagnetic interference effect of dental equipment on cardiac implantable electrical devices: A systematic review.

BACKGROUND: The electromagnet interference (EMI) effect resulting from using dental equipment near cardiovascular implantable electronic devices (CIEDs) is controversial based on in vitro and in vivo studies. We aimed to summarize the available evidence to investigate the safety of using dental equipment on patients with CIEDs. METHODS: An electronic search was performed in PubMed, Embase, MEDLINE Ovid, and the Cochrane Library for relevant studies published between January 2000 and May 2020. The search strategy centered on terms related to dental devices and CIEDs. Two independent reviewers determined the final inclusion of the studies in the systematic review. The EMI effect was summarized based on different dental instruments detected in in vitro or in vivo studies. RESULTS: The primary search identified 84 articles, and 18 studies were finally included in this systematic review after exclusions. Most in vitro studies (n = 12) reported background noise or severe EMI affecting CIED function at a close distance from the lead tip or at a high sensitivity setting of CIEDs. In in vivo studies (n = 6), EMI that altered CIED function was not detected at clinical distance and sensitivity settings. The summary, based on electronic apex locators, ultrasonic devices, and electric pulp testers, demonstrated the compatibility of these common dental devices with CIEDs. CONCLUSIONS: This systematic review indicates that most dental instruments can be used safely in routine dental practice. The EMI effect of dental equipment depends on the exposure distance and lead-related parameters of the CIEDs.

Cellular Uptake and Delivery-Dependent Effects of Tb3+-Doped Hydroxyapatite Nanorods.

With the increasing interest in hydroxyapatite (HA) nanostructures for use in biomedicine, the systematic evaluation of their potential effects on biological systems is becoming critically important. In this work, we report the in vitro cellular uptake, in vivo tissue distributions and toxicity of Tb3+-doped HA (HA-Tb) after short-, intermediate-, and long-term exposure. Transmission electron microscopy analysis indicated that HA-Tb was taken up by cells via vesicle endocytosis. Cell proliferation and cytotoxicity assay, combined with confocal laser scanning microscopy, indicated excellent cell viability with no changes in cell morphology at the examined doses. Three HA-Tb delivery methods (intraperitoneal, intragastric, and intravenous) resulted in similar time-dependent tissue distributions, while intraperitoneal injection produced the highest bioavailability. HA-Tb initially accumulated in livers and intestines of rats (4 h to one day after administration), then became increasingly distributed in the kidney and bladder (seven days), and finally decreased in all tissues after 30 to 90 days. No histopathological abnormalities or lesions related to treatment with HA-Tb were observed. These results suggest that HA-Tb has minimal in vitro and in vivo toxicity, regardless of the delivery mode, time, and dose. The findings provide a foundation for the design and development of HA for biological applications.

[Development of human embryonic stem cell platforms for human health-safety evaluation].

The human embryonic stem cells (hESCs) serve as a self-renewable, genetically-healthy, pluripotent and single source of all body cells, tissues and organs. Therefore, it is considered as the good standard for all human stem cells by US, Europe and international authorities. In this study, the standard and healthy human mesenchymal progenitors, ligament tissues, cardiomyocytes, keratinocytes, primary neurons, fibroblasts, and salivary serous cells were differentiated from hESCs. The human cellular health-safety of NaF, retinoic acid, 5-fluorouracil, dexamethasone, penicillin G, adriamycin, lead acetate PbAc, bisphenol A-biglycidyl methacrylate (Bis-GMA) were evaluated selectively on the standardized platforms of hESCs, hESCs-derived cardiomyocytes, keratinocytes, primary neurons, and fibroblasts. The evaluations were compared with those on the currently most adopted cellular platforms. Particularly, the sensitivity difference of PM2.5 toxicity on standardized and healthy hESCs derived fibroblasts, currently adopted immortalized human bronchial epithelial cells Beas-2B and human umbilical vein endothelial cells (HUVECs) were evaluated. The RESULTS showed that the standardized hESCs cellular platforms provided more sensitivity and accuracy for human cellular health-safety evaluation.

[Three-dimensional measurement and facial symmetry analysis for the craniofacial structure of people in North China with normal occlusion].

OBJECTIVE: To investigate the internal regularities and symmetry of craniofacial structures from adults with normal occlusion in North China. METHODS: The study consisted of 60 volunteers who were examined with spiral 3D computed tomography (CT). The axial images of craniofacial structure were reconstructed into 3D models and analyzed by using Proplan 1.2 software to measure the internal regularities and symmetry of craniofacial structures. RESULTS: All the linear measurement's value of the males were bigger than those of the females (P<0.05). There were no significant differences in the ratio measurements between the males and the females(P>0.05). Facial asymmetry was less than 10% in all the images. CONCLUSION: CT is an effective method for three-dimensional analyses of craniofacial structure and symmetry. There are certain and harmonious regularities in normal 3D craniofacial structures. The 3D craniofacial structure database of people with normal occlusion can provide standards and references for diagnosis and treatment planning of craniofacial deformities.