Preliminary study of the homeostatic regulation of osseointegration by nanotube topology.

The ideal implant surface plays a substantial role in maintaining bone homeostasis by simultaneously promoting osteoblast differentiation and limiting overactive osteoclast activity to a certain extent, which leads to satisfactory dynamic osseointegration. However, the rational search for implant materials with an ideal surface structure is challenging and a hot research topic in the field of tissue engineering. In this study, we constructed titanium dioxide titanium nanotubes (TNTs) by anodic oxidation and found that this structure significantly promoted osteoblast differentiation and inhibited osteoclast formation and function while simultaneously inhibiting the total protein levels of proline-rich tyrosine kinase 2 (PYK2) and focal adhesion kinase (FAK). Knockdown of the PYK2 gene by siRNA significantly suppressed the number and osteoclastic differentiation activity of mouse bone marrow mononuclear cells (BMMs), while overexpression of PYK2 inhibited osteogenesis and increased osteoclastic activity. Surprisingly, we found for the first time that neither knockdown nor overexpression of the FAK gene alone caused changes in osteogenesis or osteoclastic function. More importantly, compared with deletion or overexpression of PYK2/FAK alone, coexpression or cosilencing of the two kinases accelerated the effects of TNTs on osteoclastic and osteogenic differentiation on the surface of cells. Furthermore, in vivo experiments revealed a significant increase in positiveexpression-PYK2 cells on the surface of TNTs, but no significant change in positiveexpression -FAK cells was observed. In summary, PYK2 is a key effector molecule by which osteoblasts sense nanotopological mechanical signals and maintain bone homeostasis around implants. These results provide a referable molecular mechanism for the future development and design of homeostasis-based regulatory implant biomaterials.

Baicalin Weakens the Virulence of Porcine Extraintestinal Pathogenic Escherichia coli by Inhibiting the LuxS/AI-2 Quorum-Sensing System.

Porcine extraintestinal pathogenic Escherichia coli (ExPEC) is a pathogenic bacterium that causes huge economic losses to the pig farming industry and considerably threatens human health. The quorum sensing (QS) system plays a crucial role in the survival and pathogenesis of pathogenic bacteria. Hence, it is a viable approach to prevent ExPEC infection by compromising the QS system, particularly the LuxS/AI-2 system. In this study, we investigated the effects of baicalin on the LuxS/AI-2 system of ExPEC. Baicalin at concentrations of 25, 50, and 100 µg/mL significantly diminished the survival ability of ExPEC in hostile environments and could inhibit the biofilm formation and autoagglutination ability in ExPEC. Moreover, baicalin dose-dependently decreased the production of AI-2 and down-regulated the expression level of luxS in PCN033. These results suggest that baicalin can weaken the virulence of PCN033 by inhibiting the LuxS/AI-2 system. After the gene luxS was deleted, AI-2 production in PCN033 was almost completely eliminated, similar to the effect of baicalin on the production of AI-2 in PCN033. This indicates that baicalin reduced the production of AI-2 by inhibiting the expression level of luxS in ExPEC. In addition, the animal experiment further showed the potential of baicalin as a LuxS/AI-2 system inhibitor to prevent ExPEC infection. This study highlights the potential of baicalin as a natural quorum-sensing inhibitor for therapeutic applications in preventing ExPEC infection by targeting the LuxS/AI-2 system.

Tobacco toxins trigger bone marrow mesenchymal stem cells aging by inhibiting mitophagy.

Smoking disrupts bone homeostasis and serves as an independent risk factor for the development and progression of osteoporosis. Tobacco toxins inhibit the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), promote BMSCs aging and exhaustion, but the specific mechanisms are not yet fully understood. Herein, we successfully established a smoking-related osteoporosis (SROP) model in rats and mice through intraperitoneal injection of cigarette smoke extract (CSE), which significantly reduced bone density and induced aging and inhibited osteogenic differentiation of BMSCs both in vivo and in vitro. Bioinformatics analysis and in vitro experiments confirmed that CSE disrupts mitochondrial homeostasis through oxidative stress and inhibition of mitophagy. Furthermore, we discovered that CSE induced BMSCs aging by upregulating phosphorylated AKT, which in turn inhibited the expression of FOXO3a and the Pink1/Parkin pathway, leading to the suppression of mitophagy and the accumulation of damaged mitochondria. MitoQ, a mitochondrial-targeted antioxidant and mitophagy agonist, was effective in reducing CSE-induced mitochondrial oxidative stress, promoting mitophagy, significantly downregulating the expression of aging markers in BMSCs, restoring osteogenic differentiation, and alleviating bone loss and autophagy levels in CSE-exposed mice. In summary, our results suggest that BMSCs aging caused by the inhibition of mitophagy through the AKT/FOXO3a/Pink1/Parkin axis is a key mechanism in smoking-related osteoporosis.

Mn-Based Artificial Mitochondrial Complex "VI" Acts as an Electron and Free Radical Conversion Factory to Suppress Macrophage Inflammatory Response.

Disturbance in the mitochondrial electron transport chain (ETC) is a key factor in the emerging discovery of immune cell activation in inflammatory diseases, yet specific regulation of ETC homeostasis is extremely challenging. In this paper, a mitochondrial complex biomimetic nanozyme (MCBN), which plays the role of an artificial "VI" complex and acts as an electron and free radical conversion factory to regulate ETC homeostasis is creatively developed. MCBN is composed of bovine serum albumin (BSA), polyethylene glycol (PEG), and triphenylphosphine (TPP) hierarchically encapsulating MnO2 polycrystalline particles. It has nanoscale size and biological properties like natural complexes. In vivo and in vitro experiments confirm that MCBN can target the mitochondrial complexes of inflammatory macrophages, absorb excess electrons in ETC, and convert the electrons to decompose H2 O2 . By reducing the ROS and ATP bursts and converting existing free radicals, inhibiting NLRP3 inflammatory vesicle activation and NF-κB signaling pathway, MCBN effectively suppresses macrophage M1 activation and inflammatory factor secretion. It also demonstrates good inflammation control and significantly alleviates alveolar bone loss in a mouse model of ligation-induced periodontitis. This is the first nanozyme that mimics the mitochondrial complex and regulates ETC, demonstrating the potential application of MCBN in immune diseases.

Nature of ultrafast dynamics in the lowest-lying singlet excited state of [Ru(bpy)3]2.

This work presents mechanisms to rationalize the nature of ultrafast photochemical and photophysical processes on the first singlet metal-ligand charge transfer state (1MLCT1) of the [Ru(bpy)3]2+ complex. The 1MLCT1 state is the lowest-lying singlet excited state and the most important intermediate in the early evolution of photoexcited [Ru(bpy)3]2+*. The results obtained from simple but interpretable theoretical models show that the 1MLCT1 state can be very quickly formed via both direct photo-excitation and internal conversions and then can efficiently relax to its equilibrium geometry in ca. 5 fs. The interligand electron transfer (ILET) on the potential energy surface of the 1MLCT1 state is also extremely fast, with a rate constant of ca. 1.38 × 1013 s-1. The ultrafast ILET implies that the excited electron can dynamically delocalize over the three bpy ligands, despite the fact that the excited electron may be localized on either one of the three ligands at the equilibrium geometries of the three symmetric equivalent minima. Since rapid ILET essentially suggests delocalization, the long-standing controversy in inorganic photophysics-whether the excited electron is localized or delocalized-may therefore be calmed down to some extent.

Tobacco toxins induce osteoporosis through ferroptosis.

Clinical epidemiological studies have confirmed that tobacco smoking disrupts bone homeostasis and is an independent risk factor for the development of osteoporosis. The low viability and inferior osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) are important etiologies of osteoporosis. However, few basic studies have elucidated the specific mechanisms that tobacco toxins devastated BMSCs and consequently induced or exacerbated osteoporosis. Herein, our clinical data showed the bone mineral density (BMD) values of femoral neck in smokers were significantly lower than non-smokers, meanwhile cigarette smoke extract (CSE) exposure led to a significant decrease of BMD in rats and dysfunction of rat BMSCs (rBMSCs). Transcriptomic analysis and phenotype experiments suggested that the ferroptosis pathway was significantly activated in CSE-treated rBMSCs. Accumulated intracellular reactive oxygen species activated AMPK signaling, furtherly promoted NCOA4-mediated ferritin-selective autophagic processes, increased labial iron pool and lipid peroxidation deposition, and ultimately led to ferroptosis in rBMSCs. Importantly, in vivo utilization of ferroptosis and ferritinophagy inhibitors significantly alleviated BMD loss in CSE-exposed rats. Our study innovatively reveals the key mechanism of smoking-related osteoporosis, and provides a possible route targeting on the perspective of BMSC ferroptosis for future prevention and treatment of smoking-related bone homeostasis imbalance.

Baicalin Weakens the Porcine ExPEC-Induced Inflammatory Response in 3D4/21 Cells by Inhibiting the Expression of NF-κB/MAPK Signaling Pathways and Reducing NLRP3 Inflammasome Activation.

Porcine extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of death in pigs and has led to considerable economic losses for the pig industry. Porcine ExPEC infections often cause systemic inflammatory responses in pigs, characterized by meningitis, arthritis, pneumonia, and septicemia. Baicalin has been reported to possess potent anti-inflammatory activity, but its function in porcine ExPEC remains unknown. The aim of this study was to explore the protective effect and mechanism of baicalin against the porcine ExPEC-induced inflammatory responses in 3D4/21 cells. After treatment with baicalin, the effects on cell damage, the level of pro-inflammatory cytokines, the expression of nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathways, and the activation of NOD-like receptor protein 3 (NLRP3) inflammasomes were examined. Our results show that baicalin significantly reduced the damage to 3D4/21 cells infected with porcine ExPEC PCN033. Further study showed that baicalin significantly reduced the transcription and expression of pro-inflammatory cytokines such as interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and interleukin-8 (IL-8). Furthermore, baicalin inhibited the phosphorylation of proteins such as P65, nuclear factor κB inhibitor α (IκBα), extracellular regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and P38 and reduced the expression levels of proteins such as NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), and caspase-1. These results reveal that baicalin reduced the damage to 3D4/21 cells by inhibiting the expression of NF-κB/MAPK signaling pathways and blocking NLRP3 inflammasome activation in 3D4/21 cells infected with porcine ExPEC. Taken together, these results suggest that baicalin may have potential as a medicine for the treatment of porcine ExPEC-infected pigs by regulating inflammatory responses. This study provides a novel potential pharmaco-therapeutic approach to preventing porcine ExPEC infection.

Molecularly imprinted polymer coating-assisted CsPbBr3 perovskite quantum dots/TiO2 inverse opal heterojunctions for the photoelectrochemical detection of cholesterol.

Photoelectrochemical sensors have outstanding advantages including high sensitivity and miniaturization for outdoor use. Recently, perovskite quantum dots have attracted significant attention due to their high photoluminescence quantum yield. Nonetheless, there is still a strong need to improve their performance in challenging aqueous biological applications. In this paper, based on the molecularly imprinted polymer encapsulation of CsPbBr3 perovskite quantum dot/TiO2 inverse opal heterojunction structures, linear photoelectrochemical detection of cholesterol in aqueous solution was obtained without the involvement of an enzyme. The attenuation of photocurrent intensity under intermittent irradiation within 900 s (45 on/off cycles) was only 8.6%, demonstrating the superior stability of CsPbBr3 based sensor here. At the same time, the minimum detection limit of 1.22 × 10-9 mol L-1 in buffer conditions was lower than that reported for cholesterol photoelectric sensors. It has also been shown that the photoelectrochemical sensor of CsPbBr3 here outperformed that of CH3NH3PbBr3, which is another important member of the perovskite family. Finally, the proposed photoelectrochemical sensor platform was successfully applied in the determination of cholesterol in challenging serum with satisfactory recovery. The synergism among CsPbBr3 perovskite quantum dots, TiO2 inverse opal structure and imprinted polymer has led to greatly improved water stability, super selectivity and sensitivity, thus promoting the development of perovskite-based biological sensors.

Nanotube patterning reduces macrophage inflammatory response via nuclear mechanotransduction.

The inflammatory immune environment surrounding titanium bone implants determines the formation of osseointegration, and nanopatterning on implant surfaces modulates the immune microenvironment in the implant region. Among many related mechanisms, the mechanism by which nanopatterning controls macrophage inflammatory response still needs to be elucidated. In this paper, we found that inhibition of the nuclear envelope protein lamin A/C by titania nanotubes (TNTs) reduced the macrophage inflammatory response. Knockdown of lamin A/C reduced macrophage inflammatory marker expression, while overexpression of lamin A/C significantly elevated inflammatory marker expression. We further found that suppression of lamin A/C by TNTs limited actin polymerization, thereby reducing the nuclear translocation of the actin-dependent transcriptional cofactor MRTF-A, which subsequently reduced the inflammatory response. In addition, emerin, which is a key link between lamin A/C and actin, was delocalized from the nucleus in response to mechanical stimulation by TNTs, resulting in reduced actin organization. Under inflammatory conditions, TNTs exerted favourable osteoimmunomodulatory effects on the osteogenic differentiation of mouse bone marrow-derived stem cells (mBMSCs) in vitro and osseointegration in vivo. This study shows and confirms for the first time that lamin A/C-mediated nuclear mechanotransduction controls macrophage inflammatory response, and this study provides a theoretical basis for the future design of immunomodulatory nanomorphologies on the surface of metallic bone implants.

Parental detection of neonatal jaundice using a low-cost colour card: a multicentre prospective study.

BACKGROUND: Since most infants are usually discharged before age 48-72 hours, peak bilirubin levels will almost always occur after discharge. Parents may be the first to observe the onset of jaundice after discharge, but visual assessment is unreliable. The jaundice colour card (JCard) is a low-cost icterometer designed for the assessment of neonatal jaundice. The objective of this study was to evaluate parental use of JCard to detect jaundice in neonates. METHODS: We conducted a multicentre, prospective, observational cohort study in nine sites across China. A total of 1161 newborns ≥35 weeks of gestation were enrolled in the study. Measurements of total serum bilirubin (TSB) levels were based on clinical indications. The JCard measurements by parents and paediatricians were compared with the TSB. RESULTS: JCard values of parents and paediatricians were correlated with TSB (r=0.754 and 0.788, respectively). The parents' and paediatricians' JCard values 9 had sensitivities of 95.2% vs 97.6% and specificities of 84.5% vs 71.7% for identifying neonates with TSB ≥153.9 µmol/L. The parents' and paediatricians' JCard values 15 had sensitivities of 79.9% vs 89.0% and specificities of 66.7% vs 64.9% for identifying neonates with TSB ≥256.5 µmol/L. Areas under the receiver operating characteristic curves of parents for identifying TSB ≥119.7, ≥153.9, ≥205.2, and ≥256.5 µmol/L were 0.967, 0.960, 0.915, and 0.813, respectively, and those of paediatricians were 0.966, 0.961, 0.926 and 0.840, respectively. The intraclass correlation coefficient was 0.933 between parents and paediatricians. CONCLUSION: The JCard can be used to classify different levels of bilirubin, but it is less accurate with high bilirubin levels. The JCard diagnostic performance of parents was slightly lower than that of paediatricians.

Chromatin remodeling and nucleoskeleton synergistically control osteogenic differentiation in different matrix stiffnesses.

Matrix stiffness plays an important role in determining cell differentiation. The expression of cell differentiation-associated genes can be regulated by chromatin remodeling-mediated DNA accessibility. However, the effect of matrix stiffness on DNA accessibility and its significance for cell differentiation have not been investigated. In this study, gelatin methacryloyl (GelMA) hydrogels with different degrees of substitution were used to simulate soft, medium, and stiff matrices, and it was found that a stiff matrix promoted osteogenic differentiation of MC3T3-E1 cells by activating the Wnt pathway. In the soft matrix, the acetylation level of histones in cells was decreased, and chromatin condensed into a closed conformation, affecting the activation of ß-catenin target genes (Axin2, c-Myc). Histone deacetylase inhibitor (TSA) was used to decondense chromatin. However, there was no significant increase in the expression of ß-catenin target genes and the osteogenic protein Runx2. Further studies revealed that ß-catenin was restricted to the cytoplasm due to the downregulation of lamin A/C in the soft matrix. Overexpression of lamin A/C and concomitant treatment of cells with TSA successfully activated ß-catenin/Wnt signaling in cells in the soft matrix. The results of this innovative study revealed that matrix stiffness regulates cell osteogenic differentiation through multiple pathways, which involve complex interactions between transcription factors, epigenetic modifications of histones, and the nucleoskeleton. This trio is critical for the future design of bionic extracellular matrix biomaterials.

Mitochondrial Calcium Ion Nanogluttons Alleviate Periodontitis via Controlling mPTPs.

The mitochondrial permeability transition (mPT) directly affects mitochondrial function in macrophages. Under inflammatory conditions, mitochondrial calcium ion (mitoCa2+ ) overload triggers the persistent opening of mPT pores (mPTPs), further aggravating Ca2+ overload and increasing reactive oxygen species (ROS) to form an adverse cycle. However, there are currently no effective drugs targeting mPTPs to confine or unload excess Ca2+ . It is novelly demonstrated that the initiation of periodontitis and the activation of proinflammatory macrophages depend on the persistent overopening of mPTPs, which is mainly triggered by mitoCa2+ overload and facilitates further mitochondrial ROS leakage into the cytoplasm. To solve the above problems, mitochondrial-targeted "nanogluttons" with PEG-TPP conjugated to the surface of PAMAM and BAPTA-AM encapsulated in the core are designed. These nanogluttons can efficiently "glut" Ca2+ around and inside mitochondria to effectively control the sustained opening of mPTPs. As a result, the nanogluttons significantly inhibit the inflammatory activation of macrophages. Further studies also unexpectedly reveal that the alleviation of local periodontal inflammation in mice is accompanied by diminished osteoclast activity and reduced bone loss. This provides a promising strategy for mitochondria-targeted intervention in inflammatory bone loss in periodontitis and can be extended to treat other chronic inflammatory diseases associated with mitoCa2+ overload.

Genetically engineered cell membrane-coated nanoparticles for antibacterial and immunoregulatory dual-function treatment of ligature-induced periodontitis.

Purpose: In order to overcome the problem that conventional pharmacological treatments of periodontitis cannot effectively synergizing antimicrobial and immunomodulation, inspired by the critical role of toll-like receptor 4 (TLR4) in bacterial recognition and immune activation, we demonstrated a combined antibacterial-immunoregulatory strategy based on biomimetic nanoparticles. Methods: Functioned cell membranes and silk fibroin nanoparticles (SNs) loaded with minocycline hydrochloride (Mino) were used to prepare a biomimetic nanoparticle (MSNCs). SNs and MSNCs were characterized by Scanning Electron Microscope, size, zeta potential, dispersion index. At the same time, SNs were characterized by cell counting kit-8 and real-time Polymerase Chain Reaction (RT-PCR). TLR4-expressing cell membranes were characterized by RT-PCR and western blot (WB). Cell membrane coating was characterized by Transmission Electron Microscope (TEM), the Bradford staining and WB. Then, Laser confocal, flow cytometry and agar plate coating were evaluated in vitro with antibacterial effects, RT-PCR was simultaneously evaluated with immunoregulatory effects. Finally, Anti-inflammatory treatment of MSNCs was evaluated in a ligature-induced periodontitis (LIP) mouse model. Results: Successfully prepared cell membranes overexpressing TLR4 and constructed MSNCs. In vitro studies had shown that MSNCs effectively targeted bacteria via TLR4 and acted as molecular decoys to competitively neutralize lipopolysaccharide (LPS) in the microenvironment as well as inhibit inflammatory activation of macrophages. In vivo, MSNCs effectively attenuated periodontal tissue inflammation and alveolar bone loss in a LIP mouse model. Conclusion: MSNCs have good targeted antibacterial and immunoregulatory effects, and provide a new and effective strategy for the treatment of periodontitis and have good potential for application in various types of pathogenic bacterial infections.

Telemedicine in the Battle with 2019 Novel Coronavirus Disease (COVID-19) in Henan Province, China: A Narrative Study.

Background and Objectives: Based on practical services of the Henan Province Telemedicine Center (HTCC), the purpose of this study is to investigate the design, construction, implementation, and application effect of a specific telemedicine system in response to the coronavirus disease 2019 (COVID-19). Methods: Data on COVID-19 cases from December 31, 2019, through October 17, 2022, were collected from official websites. Data and information of telemedicine services related to COVID-19 in HTCC were collected and analyzed, and relevant graphical representations were plotted. Results: All the 147 COVID-19 designated hospitals in the Henan Province were covered by the specific telemedicine system. The cities near to the Hubei Province in the south of Henan tended to be with more COVID-19 cases, where more COVID-19-related telemedicine services were conducted. For the telemedicine system, function modules, including real-time monitoring, command and dispatch, intractable cases transfer, remote guidance, and data sharing, were designed and realized to deal with COVID-19. Through the system, telemedicine services involved COVID-19 such as epidemic surveillance, emergency rescue, case discussion, diagnosis and treatment, remote ward-round, and distance education were performed. During the period between February 2 and March 3, 2020, 646 COVID-19 patients were served by the telemedicine system, with an improvement rate of 73.2%. Conclusions: Telemedicine can improve the diagnosis and treatment of COVID-19 patients, which play a helpful role in curbing the COVID-19 epidemic. Given the current global COVID-19 pandemic and the potential re-emerge of novel zoonotic pathogens in the future, the use of telemedicine would be imperative to fight against the pandemic.

[Huayu Tongluo moxibustion combined with intradermal needling in patients with mild to moderate depression after cerebral infarction].

OBJECTIVE: To observe the effect of Huayu Tongluo (resolving stasis and promoting collateral circulation) moxibustion combined with intradermal needling on depressive symptoms, quality of life and cognitive impairment in patients with mild to moderate depression after cerebral infarction on the basis of western medicine treatment. METHODS: Fifty patients with mild to moderate depression after cerebral infarction were randomly divided into an acupuncture combined with western medication group (group A, 25 cases) and a western medication group (group B, 25 cases). In the group B, paroxetine hydrochloride tablets were taken orally, 20 mg after breakfast, once a day, and the dose could be adjusted to the maximum 40 mg/d according to the patients' condition, for 4 weeks totally. On the basis of the treatment in the group B, the group A was treated with Huayu Tongluo moxibustion, namely aconite cake-separated moxibustion at Baihui (GV 20) and suspended moxibustion at Dazhui (GV 14) and Shenting (GV 24), combined with intradermal needling at Shenmen (HT 7), Jianshi (PC 5), Zusanli (ST 36), etc. Huayu Tongluo moxibustion was performed 6 times a week, and intradermal needling was performed 3 times a week，for 4 weeks totally. In the two groups, the scores of Hamilton depression scale (HAMD), stroke specific quality of life scale (SS-QOL) and mini mental state examination (MMSE) were observed before and after treatment, and the clinical efficacy and safety were compared. RESULTS: After treatment, the HAMD score in the each group was decreased compared with that before treatment (P<0.05), and that in the group A was lower than the group B (P<0.05); after treatment, the SS-QOL score in the group A and MMSE score in the two groups were increased compared with those before treatment (P<0.05), and the SS-QOL score in the group A was higher than the group B (P<0.05). The total effective rate was 88.0% (22/25) in the group A, which was higher than 60.0% (15/25) in the group B (P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups (4.0% [1/25] vs 16.0%[4/25], P>0.05). CONCLUSION: On the basis of the treatment of western medication paroxetine hydrochloride tablets, Huayu Tongluo moxibustion combined with intradermal needling therapy can effectively improve the depressive symptoms, quality of life and cognitive impairment of patients with mild to moderate depression after cerebral infarction.

Compact and accurate ab initio valence bond wave functions for electron transfer: The classic but challenging covalent-ionic interaction in LiF.

This paper combines the valence bond block diabatization approach with the idea of orbital breathing. With highly compact wave functions, the breathing orbital valence bond (BOVB) method is applied to investigate several atomic and molecular properties, including the electron affinity of F, the adiabatic and diabatic potential energy curves and the dipole moment curves of the two lowest-lying 1Σ+ states, the electronic coupling curve and the crossing distance of the two diabatic states, and the spectroscopic constants of the ground states for LiF. The configuration selection scheme proposed in this work is quite general, requiring only the selection of several de-excitation and excitation orbitals in a sense like the restricted active space self-consistent field method. Practically, this is also the first time that BOVB results are extrapolated to complete basis set limit. Armed with the chemical intuition provided by valence bond theory, the classic but challenging covalent-ionic interaction in the title molecule is not only conceptually interpreted but also accurately computed.

Hypolimnetic deoxygenation enhanced production and export of recalcitrant dissolved organic matter in a large stratified reservoir.

Global impoundment of river systems represents a major anthropogenic forcing to carbon cycling in reservoirs with seasonal thermal stratification. Currently, a quantitative and mechanistic understanding of how hypolimnetic deoxygenation in stratified reservoirs alters dissolved organic matter (DOM) cycling and lateral transport along the river continuum remains unresolved. Herein, we used optical and high-resolution mass spectrometric analyses to track seasonal and spatial compositional changes of DOM from a large, subtropical impounded river in southeast China. Aliphatic compounds were contributed by algal blooms to epilimnetic DOM during the spring/summer and by baseflow to the overall DOM pool during low-discharge periods. Deoxygenation-driven hypolimnetic mineralization enhanced in situ production of bio-refractory molecules and humic-like fluorescent DOM (FDOMH) by utilizing bio-labile DOM and settling biogenic particles during periods of stratification. Production efficiency of hypolimnetic FDOMH was 159-444% higher than that of the global dark ocean, and was strongly regulated by temperature and possibly substrate supply. The in situ production rate of hypolimnetic FDOMH was four to five orders-of-magnitude higher than the dark ocean, with much faster turnover rates in dark inland waters versus the dark ocean. Collectively, these findings indicate that the hypolimnion is a hotspot for microbial carbon transformations, and hence an important source and pool of refractory DOM in aquatic systems. The lateral FDOMH flux increased 10.8-32.1% due to hypolimnetic reservoir release during periods of stratification, highlighting the importance of incorporating hypolimnetic carbon transformations into models for carbon cycling of inland waters and the land-sea interface.

Dual selective sensor for exosomes in serum using magnetic imprinted polymer isolation sandwiched with aptamer/graphene oxide based FRET fluorescent ignition.

The selective and sensitive detection of cancerous exosomes in serum is critical for early disease diagnosis and improved prognosis. Previous exosome-related research has been limited by a lack of well-understanding in exosomes as well as the challenging background interference of body fluid. Molecularly imprinted polymers (MIPs) and nucleic acid aptamers can be regarded as the two alternatives to antibodies. When using imprinted polymer technology, comprehensive and precise information about the target constituents is not required. In this study, a novel kind of dual selective fluorescent nanosensor for the poorly characterized exosomes was constructed by integrating magnetic MIP selective exosome capture sandwiched with an aptamer/graphene oxide fluorescence resonance energy transfer system (FRET) based selective 'turn-on' exosome labeling heterogeneously. The overall strategy performance was successively evaluated using lysozyme and exosomes as targets. Good linearity and high sensitivity achieved were demonstrated. The LOD of exosomal detection in serum was 2.43 × 106 particles/mL, lower than other immunology based detection methods. The discrimination between serum from breast cancer patients and healthy people was also primarily studied. In conclusion, the developed sensor with outstanding selectivity, high detection sensitivity, simplicity, low cost, and wide applicability for known or unknown targets present significant potential in challenging clinical diagnosis.

pH and lipase-responsive nanocarrier-mediated dual drug delivery system to treat periodontitis in diabetic rats.

Precise and controlled drug delivery to treat periodontitis in patients with diabetes remains a significant clinical challenge. Nanoparticle-based drug delivery systems offer a potential therapeutic strategy; however, the low loading efficiency, non-responsiveness, and single effect of conventional nanoparticles hinder their clinical application. In this study, we designed a novel self-assembled, dual responsive, and dual drug-loading nanocarrier system, which comprised two parts: the hydrophobic lipid core formed by 1, 2-Distearoyl-sn-glycero-3-phosphoethanolamine-Poly (ethylene glycol) (DSPE-PEG) loaded with alpha-lipoic acid (ALA); and a hydrophilic shell comprising a poly (amidoamine) dendrimer (PAMAM) that electrostatically adsorbed minocycline hydrochloride (Mino). This unique design allows the controlled release of antioxidant/ALA under lipase stimulation from periodontal pathogens and antimicrobial/Mino under the low pH of the inflammatory microenvironment. In vivo and in vitro studies confirmed that this dual nanocarrier could inhibit the formation of subgingival microbial colonies while promoting osteogenic differentiation of cells under diabetic pathological conditions, and ameliorated periodontal bone resorption. This effective and versatile drug-delivery strategy has good potential applications to inhibit diabetes-associated periodontal bone loss.

Dendrimer-modified gelatin methacrylate hydrogels carrying adipose-derived stromal/stem cells promote cartilage regeneration.

BACKGROUND: Cartilage defects pose a significant burden on medical treatment, leading to an urgent need to develop regenerative medicine approaches for cartilage repair, such as stem cell therapy. However, the direct injection of stem cells can result in insufficient delivery or inaccurate differentiation. Hence, it is necessary to choose appropriate stem cell delivery scaffolds with high biocompatibility, injectability and chondral differentiation induction ability for cartilage regeneration. METHODS: In this study, the photocrosslinked gelatin methacrylate (GelMA) hydrogel with high cell affinity and plasticity was selected and strengthened by incorporating methacrylic anhydride-modified poly(amidoamine) (PAMAM-MA) to fabricate an adipose-derived stromal/stem cells (ASCs) delivery scaffold for cartilage repair. The physiochemical properties of the GelMA/PAMAM-MA hydrogel, including the internal structure, stability and mechanical properties, were tested. Then, ASCs were encapsulated into the hydrogels to determine the in vitro and in vivo chondrogenic differentiation induction abilities of the GelMA/PAMAM-MA hydrogel. RESULTS: Compared with the GelMA hydrogel, the GelMA/PAMAM-MA hydrogel exhibited more uniform structure, stability and mechanical properties. Moreover, on the basis of good biocompatibility, the hybrid hydrogel was proven to exert a sufficient ability to promote cartilage regeneration by in vitro three-dimensional (3D) culture of rASCs and in vivo articular cartilage defect repair. CONCLUSIONS: The injectable photocrosslinked GelMA/PAMAM-MA hydrogel was proven to be a capable stem cell carrier for cartilage repair and provides new insight into the design strategy of stem cell delivery scaffolds.