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Xun Huang,1,2 Jiexiang He,2,3 Huan-tian Zhang,1 Kai Sun,2,3 Jie Yang,1 Huajun Wang,1 Hongxin Zhang,2,3 Zhenzhao Guo,2,3 Zhen-gang Zha,1 Changren Zhou2,31Department of Bone and Joint Surgery, The First Affiliated Hospital of Jinan University, 2Department of Materials Science and Engineering, Jinan University, 3Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou, ChinaAbstract: CD44 ligand–receptor interactions are known to be involved in regulating cell migration and tumor cell metastasis. High expression levels of CD44 correlate with a poor prognosis of melanoma patients. In order to understand not only the mechanistic basis for dacarbazine (DTIC)-based melanoma treatment but also the reason for the poor prognosis of melanoma patients treated with DTIC, dynamic force spectroscopy was used to structurally map single native CD44-coupled receptors on the surface of melanoma cells. The effect of DTIC treatment was quantified by the dynamic binding strength and the ligand-binding free-energy landscape. The results demonstrated no obvious effect of DTIC on the unbinding force between CD44 ligand and its receptor, even when the CD44 nanodomains were reduced significantly. However, DTIC did perturb the kinetic and thermodynamic interactions of the CD44 ligand–receptor, with a resultant greater dissociation rate, lower affinity, lower binding free energy, and a narrower energy valley for the free-energy landscape. For cells treated with 25 and 75 µg/mL DTIC for 24 hours, the dissociation constant for CD44 increased 9- and 70-fold, respectively. The CD44 ligand binding free energy decreased from 9.94 for untreated cells to 8.65 and 7.39 kcal/mol for DTIC-treated cells, which indicated that the CD44 ligand–receptor complexes on DTIC-treated melanoma cells were less stable than on untreated cells. However, affinity remained in the micromolar range, rather than the millimolar range associated with nonaffinity ligands. Hence, the CD44 receptor could still be activated, resulting in intracellular signaling that could trigger a cellular response. These results demonstrate DTIC perturbs, but not completely inhibits, the binding of CD44 ligand to membrane receptors, suggesting a basis for the poor prognosis associated with DTIC treatment of melanoma. Overall, atomic force microscopy-based nanoscopic methods offer thermodynamic and kinetic insight into the effect of DTIC on the CD44 ligand-binding process.Keywords: atomic force microscopy, tumor, dynamic force spectroscopy, kinetic and thermodynamic interactions, affinity, nanoindentation

Pikas (Lagomorpha: Ochotonidae) are small mouse-like lagomorphs. To investigate their adaptation to different ecological environments during their dispersal from the Qinghai-Xizang (Tibet) Plateau (QTP), we collected 226 pikas and measured 20 morphological characteristics and recorded habitat information. We also sequenced the genome of 81 specimens, representing 27 putative pika species. The genome-wide tree based on 4 090 coding genes identified five subgenera, i.e., Alienauroa , Conothoa , Lagotona , Ochotona , and Pika , consistent with morphometric data. Morphologically, Alienauroa and Ochotona had similar traits, including smaller size and earlier divergence time compared to other pikas. Consistently, the habitats of Alienauroa and Ochotona differed from those of the remaining subgenera. Phylogenetic signal analysis detected 83 genes significantly related to morphological characteristics, including several visual and hearing-related genes. Analysis of shared amino acid substitutions and positively selected genes (PSGs) in Alienauroa and Ochotona identified two genes, i.e., mitochondrial function-related TSFM (p.Q155E) and low-light visual sensitivity-related PROM1 (p.H419Y). Functional experiments demonstrated that TSFM-155E significantly enhanced mitochondrial function compared to TSFM-155Q in other pikas, and PROM1-419Y decreased the modeling of dynamic intracellular chloride efflux upon calcium uptake. Alienauroa and Ochotona individuals mostly inhabit different environments (e.g., subtropical forests) than other pikas, suggesting that a shift from the larger ancestral type and changes in sensory acuity and energy enhancement may have been required in their new environments. This study increases our understanding of the evolutionary history of pikas.

DNA N6-methyladenine (6 mA) is a new type of DNA methylation identified in various eukaryotic cells. However, its alteration and genomic distribution features in hepatocellular carcinoma (HCC) remain elusive. In this study, we found that N6AMT1 overexpression increased HCC cell viability, suppressed apoptosis, and enhanced migration and invasion, whereas ALKBH1 overexpression induced the opposite effects. Further, 23,779 gain-of-6 mA regions and 11,240 loss-of-6 mA regions were differentially identified in HCC tissues. The differential gain and loss of 6 mA regions were considerably enriched in intergenic regions. Moreover, 7% of the differential 6 mA modifications were associated with tumors, with 60 associated with oncogenes and 57 with tumor suppressor genes (TSGs), and 17 were common to oncogenes and TSGs. The candidate genes affected by 6 mA were filtered by gene ontology (GO) and RNA-seq. Using quantitative polymerase chain reaction (qPCR), BCL2 and PARTICL were found to be correlated with DNA 6 mA in certain HCC processes., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Blood lead poisoning is a universal and severe health problem that greatly threatens human health in various industries. Elimination of blood lead relying on chelating agents and combination with hemoperfusion adsorbents has achieved considerable progress, but it is still suffering from the compromised selectivity of adsorbents as well as in absence of real time monitoring during treatment. Herein, we proposed a selective blood lead adsorbent integrated with real-time visualized/electrochemical bi-modal monitoring based on TMPyP-bound guanosine-borate (GB) supramolecular hydrogel as potential smart hemoperfusion device. The GB hydrogel possessed stability in physiological environment, self-healing ability resistant to fluid shear, blood compatibility, selective adsorption of lead ions superior to conventional adsorbents, anti-fouling performance to blood components and renewability. Benefiting from binding with TMPyP and the intrinsic conductivity, GB hydrogel was endowed with the ability to qualitatively diagnose the presence of blood lead via simple color change and quantitatively reflect the amount of adsorbed lead from blood accurately through electrochemical technique. This work puts forward an integrated treatment/monitoring hemoperfusion device with high selectivity, simple fabrication and low-cost, providing a paradigm for next generation design of intelligent, monitorable theranostic hemopurification system, which is also an extensible platform for the other research fields such as environmental monitoring and remediation., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) is increasing globally. It is rarely noticed that the incidence of CRC is higher in patients with T2DM. What needs to be mentioned is that metformin, a commonly used clinical drug for T2DM, attracts scholars' attention because of its benefits in lowering the risk of developing CRC. Hence, we try to find the common grounds of initiation of T2DM and CRC and the reason why metformin reduces the risk of CRC in patients with T2DM. We noticed consistent changes of gut microbiota, such as elevated Bacteroides, Prevotella and Bifidobacterium and depressed Firmicutes and Lactobacillus . Furthermore, many studies in recent years have proved that the efficacy of metformin, such as improving blood glucose, depends on the gut microbiota. Coincidentally, the progression of CRC is inseparable from the contributions of gut microbiota. Therefore, we first proposed the concept of the metformin-gut microbiota-CRC (in T2DM) axis to explain the effect of metformin in reducing CRC in patients with T2DM . In this review, we elaborated the new concept and its potential clinical application value., Competing Interests: Conflict-of-interest statement: There is no conflict of interest associated with any of the senior author or other coauthors contributed their efforts in this manuscript., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)

Background: Culture is still the gold standard for the detection of genital mycoplasma which could cause urogenital infections in humans. Mycoplasma IST2 is a commercial kit widely used for the detection of M. hominis and Ureaplasma species. Its accuracy was partially impaired because clinical specimens are usually mixed with purulent or transparent mucus. We aimed to solve this problem through sample homogenization by N -acetylcysteine (NAC) treatment., Methods: Twenty-two endocervical swab samples were collected from 22 female patients with suspected mycoplasma infection, while 11 of these specimens were with purulent or transparent mucus. Mycoplasma IST2 testing kit was used for mycoplasma culture and AST for the control group and NAC-treated group., Results: Genital mycoplasma was detected in 15 of 22 samples for both groups. The colony number in 6 out of 11 purulent specimens (54.5%) was more than 10 4  CFU/ml of genital mycoplasma for the NAC-treated group, while only one of 11 (9.1%) for the control group. For the nonpurulent specimens, no significant difference had been found in colony counting of genital mycoplasma between the control group and NAC-treated group ( P > 0.05). The results of antimicrobial susceptibility testing for the NAC-treated group were highly similar to those for the control group., Conclusions: Our results demonstrate that NAC is helpful in sample homogenization and NAC treatment can improve the detection efficiency of mycoplasma with Mycoplasma IST2 testing., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Xin-Ru Mao et al.)

The deregulation of exosomal microRNAs (miRNAs) plays an important role in the progression of hepatocarcinogenesis. In this study, we highlight exosomes as mediators involved in modulating miRNA profiles in liver cancer cells after induction of the epithelial-mesenchymal transition (EMT) and metastasis. Initially, we induced EMT in a hepatocellular carcinoma cell (HCC) line (Hep3B) by stimulation with transforming growth factor-β (TGF-β) and confirmed by western blot detection of EMT markers such as vimentin and E-cadherin. Exosomes were then isolated from the cells and identified by nanoparticle tracking analysis (NTA). The isolated exosomal particles from unstimulated Hep3B cells (Hep3B exo) or TGF-β-stimulated EMT Hep3B cells (EMT-Hep3B exo) contained higher levels of exosome marker proteins, CD63 and TSG101. After incubation with EMT-Hep3B exo, Hep3B cell proliferation increased. EMT-Hep3B exo promoted the migration and invasion of Hep3B and 7721 cells. High-throughput sequencing of miRNAs and mRNA within the exosomes showed 119 upregulated and 186 downregulated miRNAs and 156 upregulated and 166 downregulated mRNA sequences in the EMT-Hep3B exo compared with the control Hep3B exo. The most differentially expressed miRNAs and target mRNA sequences were validated by RT-qPCR. Based on the known miRNA targets for specific mRNA sequences, we hypothesized that GADD45A was regulated by miR-374a-5p. Inhibition of miR-374a-5p in Hep3B cells resulted in exosomes that inhibited the proliferation, migration, and invasion of HCC cells. These results enhance our understanding of metastatic progression of liver cancer and provide a foundation for the future development of potential biomarkers for diagnosis and prognosis of hepatic cancer., Competing Interests: None., (AJTR Copyright © 2020.)

The interaction between cells and biomaterials plays a key role in cell proliferation and differentiation in tissue engineering. However, a quantitative analysis of those interactions has been less well studied. The objective of this study was to quantitative recapitulate the difference of MC3T3-E1 cell adhesion, morphological and biomechanical properties on chitosan-collagen films in terms of chemical composition. Here, the unbinding force between MC3T3-E1 cell and a series of chitosan-collagen films was probed by a real-time and in situ atomic force microscopy-single cell force spectroscopy (AFM-SCFS). Meanwhile, changes in cell morphology and Young's modulus on different chitosan-collagen films were detected by AFM. The cell area and CCK-8 results showed that cell spreading and proliferation increased with increasing collagen content. AFM observations clearly showed cell height decreased and pseudopod fusion with the collagen content increased. Cell adhesive force increased from 0.76±0.17 nN to 1.70±0.19 nN. On the contrary, cells Young's modulus, which reflected biophysical changes of cells decreased from 11.94±3.19 kPa to 1.81±0.52 kPa, respectively. It suggested that stronger cell-substrate interactions benefit cell adhesion, and better cell flexibility improve cell spreading. The findings indicate that cell morphology, adhesive force and Young's modulus are significant affected by various chitosan-collagen substrates. Those methods and quantitative results have guiding significance for investigating the mechanism of chitosan and/or collagen based cell-targeting drug carrier and the preparation of chitosan-collagen composite biomaterials., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Biomimetic composites consisting of polymer and mineral components, resembling bone in structure and composition, were produced using a rapid prototyping technique for bone tissue engineering applications. Solid freeform fabrication, known as rapid prototyping (RP) technology, allows scaffolds to be designed with pre-defined and controlled external and internal architecture. Using the indirect RP technique, a three-component scaffold with a woodpile structure, consisting of poly-L-lactic acid (PLLA), chitosan and hydroxyapatite (HA) microspheres, was produced that had a macroporosity of more than 50% together with micropores induced by lyophilization. X-ray diffraction analysis indicated that the preparation and construction of the composite scaffold did not affect the phase composition of the HA. The compressive strength and elastic modulus (E) for the PLLA composites are 0.42 and 1.46 MPa, respectively, which are much higher than those of chitosan/HA composites and resemble the properties of cellular structure. These scaffolds showed excellent biocompatibility and ability for three-dimensional tissue growth of MC3T3-E1 pre-osteoblastic cells. The pre-osteoblastic cells cultured on these scaffolds formed a network on the HA microspheres and proliferated not only in the macropore channels but also in the micropores, as seen from the histological analysis and electron microscopy. The proliferating cells formed an extracellular matrix network and also differentiated into mature osteoblasts, as indicated by alkaline phosphatase enzyme activity. The properties of these scaffolds indicate that they can be used for non-load-bearing applications., (Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Objective: To prepare morphine-loaded chitosan microspheres by emulsion ionic cross-linking and investigate the effect of initial morphine quantity and different cross-linking degrees on drug loading, encapsulation efficiency and in vitro drug release., Methods: Chitosan (with a relative molecular mass of 50,000 and deacetylation degree no less than 90%) at 100 mg and morphine at 20, 30, 40, or 50 mg were dissolved by 2% acetate and dripped slowly into 15 ml soy-bean oil containing 0.75 ml Span80. After full emulsification at 35 degrees C; for 1.5 h, the mixture was dripped slowly into sodium tripolyphosphate (10 mg/ml) at the mass ratio of 5:1, 7:1, or 9:1 to allow cross-linking for 2 h. The drug loading, encapsulation efficiency and in vitro drug release of the preparations were measured., Results: The drug loading in the microsphere increased while the encapsulation efficiency reduced with the increment of the initial morphine quantity. High cross-linking degree resulted in prolonged release time of the drug loaded in the preparations., Conclusion: The microspheres loaded with morphine allows sustained release of morphine.

The potential energy surface of the H(2)/S(2) system has been characterized at the full valence MRCI+Davidson/aug-cc-pV(Q+d)Z level of theory using geometries optimized at the MRCI/aug-cc-pVTZ level. The analysis includes channels occurring entirely on either the singlet or the triplet surface as well as those involving an intersystem crossing. RRKM-based multiple well calculations allow the prediction of rate constants in the temperature range of 300-2000 K between 0.1 and 10 bar. Of the SH recombined on the singlet surface, the stabilization of the rovibrationally excited adduct HSSH is at the low-pressure limit at 1 bar, but it has a rate comparable to that forming another major set of products H(2)S + S (via an intersystem crossing) at temperatures below 1000 K; at higher temperatures, HSS + H becomes the dominant product. For the reaction H(2)S + S, the presence of an intersystem crossing allows the formation of the singlet excited adduct H(2)SS, most of which rearranges and stabilizes as HSSH under atmospheric conditions. At high temperatures, the majority of excited HSSH dissociates to SH + SH and HSS + H. Compared to reported shock tube measurements of the reaction H(2)S + S, most of the S atom consumption can be described by the triplet abstraction route H(2)S + S --> SH + SH, especially at high temperatures, but inclusion of the singlet insertion channel provides a better description of the experimental data. The reaction HSS + H was found to proceed predominantly on the singlet surface without a chemical barrier. The formation of the major product channel SH + SH is very fast at room temperature (approximately 4 x 10(15) cm(3) mol(-1) s(-1)). While the formation of H(2)S + S or S(2) + H(2) via an isomerization or an intersystem crossing, respectively, are minor product channels, their rates are significantly higher than those of the corresponding direct triplet channels, except at elevated temperatures. Finally, due to the relatively shallow nature of its well, the stabilization of H(2)SS is negligible under conditions of likely interest.

Objective: To investigate the adsorption behavior of enamel matrix proteins (EMPs) on the enamel surface and study their effect on biomineralization of enamel using quartz crystal microbalance (QCM) technique., Methods and Results: The EMPs were adsorbed on the enamel surface to form a protein film, which was soaked in simulated body fluid solutions. After 30 days of biomimetic mineralization, the hydroxyapatite nucleation, growth and aggregation occurred with hydroxyapatite crystal formation on the enamel surface., Conclusion: The EMPs play a key role in regulating enamel mineralization.

The reaction of SH + O2 has been characterized using multireference methods, with geometries and vibrational frequencies determined at the CASSCF/cc-pVTZ level and single-point energies calculated at the MRCI/aug-cc-pV(Q+d)Z level. The dominant product channels are found to be SO + OH and HSO + O. Whereas the formation of SO + OH has a barrier of approximately 81 kJ mol-1, it is energetically more favorable than the formation of HSO + O, which is barrierless beyond the endothermicity of approximately 89 kJ mol-1 at 0 K. Thus, the reaction SH + O2 --> SO + OH is 2 orders of magnitude faster than the reaction SH + O2 --> HSO + O at room temperature, revealing that the atmospheric oxidation of SH leads directly to the formation of SO + OH with the rate coefficient of approximately 1.0 x 10(-2) cm3 mol-1 s-1. At temperatures above 1000 K, however, the rates of the two channels become comparable. This may be attributed to the entropy effects leading to the higher pre-exponential factor for the channel (forming HSO + O) via a more loose transition state than that (forming SO + OH) entailing a four-centered transition state. Whereas the hydrogen abstraction reaction producing S + HO2 is found to proceed on the quartet surface, the substantial barrier of approximately 165 kJ mol-1 means that it occurs as a minor product channel. Finally, the formation of possible products SO2 + H is prohibited due to the lack of a transition state for the direct sulfur insertion.

Objective: To study the influence of various active groups grafted on the enamel surface by means of self assembly on enamel biomineralization., Methods: The enamel was prepared by immersing the bicuspid tooth into 1 mmol/L ethanolic solution of a omega-functionalized (omega=PO4H2, SO3H, COOH or OH) group and deionized water solution of HSCH2CH2SO3Na for 24 h at room temperature. The contact angles and infrared (IR) images were used to identify the morphological changes of the enamel with chemisorption of the functional groups., Results: The contact angles and IR images showed that the omega-functionalized (omega=-PO4H2, -SO3H, -COOH, -OH or -CH3) group was chemisorbed on the enamel surface., Conclusion: Self assembled monolayers with omega-functionalized (omega=-PO4H2, -SO3H, -COOH, -OH or -CH3) group can be successfully formed on the enamel surface by hydrolyzation.

The reaction of H2S + S has been characterized at the multireference configuration interaction level with the geometries optimized using the aug-cc-pVTZ basis set and the single-point energy calculated using the aug-cc-pV(Q+d)Z basis set. As in the analogous reaction of H2 + S, the presence of an intersystem crossing enables products (SH + SH) to be formed on the singlet surface through S insertion, which bypasses the triplet barrier (19.1 kJ mol-1 relative to SH + SH) of the H abstraction route. This provides theoretical evidence for SH + SH formation without barrier beyond endothermicity at sufficiently low temperatures. The H abstraction route, however, is expected to be competitive at higher temperatures due to a much higher Arrhenius pre-exponential factor (6.9 x 10(14) cm3 mol-1 s-1 derived from TST calculation) than that of S insertion channel (3.7 x 10(13) cm3 mol-1 s-1, derived by a least-squares fit to the measurements). With a slightly higher transition-state barrier than that of the H abstraction channel, the production of S2 + H2 is less favored due to proceeding via intersystem crossing and insertion. While the formation of HSS + H is energetically unfavorable relative to SH + SH, recombination channels producing H2SS or the more stable HSSH are expected to occur under collisional stabilization conditions at high pressures.

The glass-ceramic mainly containing fluorophlogopite is one of widely used dental ceramics. In the K2O-CaO-MgO-Al2O3-SiO2-F system, a new-type glass-ceramic containing fluorophlogopite Ca-mica has been synthesized. Its crystalline was studied by XRD and EDS. The fluorophlogopite whose formula postulated K(1 - X )Ca( X/2)Mg(3)AlSi(3)O(10)F(2) was its main crystalline. The microstructure of the glass-ceramic displayed typical machinable microstructure with lath like crystals isolated and interlocking with different aspect ratio. The material also showed better bending strength (228.11 +/- 7.55 MPa). It took less than 12 minutes to fabricate a whole crown by dental CAD/CAM system with the glass-ceramic.

Background: Damaged articular cartilage has very limited capacity for spontaneous healing. Tissue engineering provides a new hope for functional cartilage repair. Creation of an appropriate cell carrier is one of the critical steps for successful tissue engineering. With the supposition that a biomimetic construct might promise to generate better effects, we developed a novel composite scaffold and investigated its potential for cartilage tissue engineering., Methods: Chitosan of 88% deacetylation was prepared via a modified base reaction procedure. A freeze-drying process was employed to fabricate a three-dimensional composite scaffold consisting of chitosan and type II collagen. The scaffold was treated with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. Ultrastructure and tensile strength of the matrix were carried out to assess its physico-chemical properties. After subcutaneous implantation in rabbits, its in vivo biocompatibility and degradability of the scaffold were determined. Its capacity to sustain chondrocyte growth and biosynthesis was evaluated through cell-scaffold co-culture in vitro., Results: The fabricated composite matrix was porous and sponge-like with interconnected pores measuring from 100-250 microm in diameter. After cross-linking, the scaffold displayed enhanced tensile strength. Subcutaneous implantation results indicated the composite matrix was biocompatible and biodegradable. In intro cell-scaffold culture showed the scaffold sustained chondrocyte proliferation and differentiation, and maintained the spheric chondrocytic phenotype. As indicated by immunohistochemical staining, the chondrocytes synthesized type II collagen., Conclusions: Chitosan and type II collagen can be well blended and developed into a porous 3-D biomimetic matrix. Results of physico-chemical and biological tests suggest the composite matrix satisfies the constraints specified for a tissue-engineered construct and may be used as a chondrocyte carrier for cartilage tissue engineering.