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The field of nanomedicine-catalyzed tumor therapy has achieved a lot of progress; however, overcoming the limitations of the tumor microenvironment (TME) to achieve the desired therapeutic effect remains a major challenge. In this study, a nanocomposite hydrogel (GH@LDO) platform combining the nanozyme CoMnFe-layered double oxides (CoMnFe-LDO) and natural enzyme glucose oxidase (GOX) was engineered to remodel the TME to enhance tumor catalytic therapy. The CoMnFe-LDO is a nanozyme that can convert endogenous H

Titanium and its alloys have been widely used for orthopedic and dental implants. However, implant failures often occur due to the implant-related bacterial infections. Herein, titanium oxide nanotubes (TNTs) with an average diameter of 75 nm were formed by anodizing on the surface of titanium, and subsequently gold (Au) nanoparticles were deposited on TNTs by magnetron sputtering (Au@TNTs). The antibacterial study shows that TNTs surface decorated with Au nanoparticles exhibits the preferable effect in restricting the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) even under dark conditions, and the antibacterial rates reached 84% and 75%, respectively. In addition, the constructed film showed no cytotoxicity. Such a selective bactericidal effect of Au@TNTs samples might be attributed to the photocatalytic memory effect, which provides a new insight in the designing of antibacterial surfaces for biomedical application.

In China, the platelet donation interval is 14 days. The eligibility criterion of plateletpheresis donors (PD) is more stringent than that of whole blood donors, so the deferral causes are very complicated. However, the deferral prevalence and causes among PDs are not well known in China.To analyse the deferral prevalence and influencing factors during pre-donation among PDs in a blood centre in Eastern China.From December 26, 2020 to December 25, 2021, all data of potential PDs during pre-donation were extracted from the register system and collected using Microsoft Excel. The number of deferred visits and the corresponding causes were retrospectively analysed, and the re-donation rate of deferred donors was calculated.A total of 19,762 visits were included in the study. Of these 17,847 (90.3%) donated platelets successfully and 1915 (9.7%) were deferred. The prevalence of deferrals was high among those less than 35 years old (p 0.05) and first-time donors (p = 0). The leading cause for deferral was elevated alanine transaminase (51.4%) followed by abnormal haematological parameters (37.15%). High white blood cell count was the first deferral factor (26.9%) in abnormal haematological parameters. In more than 2 ineligible items, low haemoglobin and haematocrit simultaneously were dominant (58.3%). The re-donation rate of repeat donors (65.4%) was higher than that of first-time donors (19.3%) (p = 0).The deferral prevalence in Chinese plateletpheresis donors was not high. First-time and young donors were more frequently deferred. The repeat donors should be of concern, especially with abnormal haematological parameters.

Traditional face or body attribute recognition can solely train and understand the specific attributes marked according to the marked content of the dataset. Most recognition systems on the market integrate specific attribute recognition algorithms. The lack of corresponding attribute data fusion leads to the problem of high diversity but poor recognition accuracy. This paper designs a recognition system based on data fusion and attribute fusion of two-dimensional images, which can fuse subtle data during training, and fuse the recognition results of overlapping attributes, to achieve multi-directional recognition of human subtle attributes, make up for the shortcomings of single recognition algorithm, and obtain more comprehensive and accurate recognition results. The experimental results show that the recognition system. Firstly, the overall recognition accuracy is above 83.5%. Secondly, it can make up for the problems of high accuracy but poor diversity of single recognition algorithm and poor accuracy of multi-feature recognition algorithm.

The exploration of electrocatalysts for hydrogen evolution, that are stable and efficient in both acidic and alkaline media, is of the momentous importance in the advancement of clean energy produc...

As the primary malignant tumor in the brain, glioblastoma exhibits a high mortality due to the challenges for complete treatment by conventional therapeutic methods. It is of great importance to develop innovative therapeutic agents and methods for treatment of glioblastoma. In this work, we report the imaging and therapy of glioblastoma by using dye sensitized core-shell NaYF4 :Yb/Tm@NaYF4 :Nd nanoparticles (CS NPs) with strong up/down-conversion luminescence, of which the ultraviolet up-conversion emissions at 348 nm and 365 nm were significantly enhanced by nearly 28 times and used to control the release of SO2 from 5-Amino-1,3-dihydrobenzo[c]thiophene 2,2-dioxide (ATD) prodrug for gas therapy, and the second near-infrared (NIR-II) down conversion emission at 1340 nm was increased 5 times and applied for imaging. We reveal that the released SO2 molecules not only caused oxidative stress damage of tumor cells, but also induced their pro-death autophagy by down-regulating the expression of p62 and up-regulating the ratio of LC3-II/LC3-I, ultimately inhibiting tumor growth. Our work demonstrates the great potential of rare earth nano-platform with functions of NIR-II imaging and photo-controlled gas therapy in the diagnosis and treatment of orthotopic glioblastoma. This article is protected by copyright. All rights reserved.

Developing dynamic and highly sensitive methods for imaging M2-type tumor-associated macrophages (TAMs) is vital for monitoring the tumor progression and assessing the therapeutic efficacy. Here, the fabrication and application of rationally designed Er-based rare-earth nanoprobes for the targeted imaging of M2-type TAMs in glioblastoma (GBM) through the second near-infrared (NIR-II) fluorescence beyond 1500 nm is reported. The NIR-IIb fluorescence of Er-based rare-earth nanoparticles can be remarkably enhanced by optimizing their core-shell structures and the shell thickness, which allows for in vivo imaging under excitation by a 980 nm laser with the lowest power density (40 mW cm

This paper introduces the application mode of the multi-access edge computing nodes system (MECNS), and analyzes the needs of the security research of the MECNS. Aiming at the security problems faced by the MECNS in the application of new energy sources such as power plant-grid-load-store system (PPGLSS), etc., the security edge computing node (ECN) is defined, and the architecture of a MECNS with a security mechanism is designed. It is based on public and private key encryption algorithm. The authorization protocol, registration protocol, cancellation protocol and the address query protocol of ECNs are proposed. In this scheme, the confidentiality and security of communication between ECNs are realized through SSL. And on this basis, the blockchain technology is integrated to propose a trusted protection mechanism for edge computing. This architecture and related protocols can ensure the verifiability and non-repudiation of ECN activities.

With the increasingly rampancy of network attacks and the steady progress of the national smart grid construction, the security protection of the power industrial control system is facing severe challenges. It is an effective means to improve the overall defense capability of the power industrial control system by formulating the security collaborative defense strategy and dynamically configuring the relevant equipment to make them have linkage response. For this purpose, a method of conflict detection for cooperative defense strategy in power industrial control system is proposed in this paper. Based on the formal description of cooperative defense strategy, the type of policy conflicts is analyzed according to the relationship between policy actions and system states. And the policy execution is simulated for detecting conflict by establishing the temporal relationship between policy actions. The experimental results show that this method can reduce the dependence on the system administrator, and can quickly and accurately find the conflicts in the collaborative defense strategy.

In the power monitoring system, it is necessary to carry out long-term continuous monitoring of the current and voltage of the monitored equipment, and the wind speed, temperature, humidity and other parameters in the monitoring environment, usually using wireless sensor networks as the communication method. Affected by factors such as power consumption, bandwidth, transmission distance, it is very important to select the appropriate data synchronization algorithm in the wireless sensor network. Inspired by the blockchain consensus algorithm, the local consensus algorithm proposed in this paper focuses on the analysis of the data synchronization mechanism between network nodes, which can reduce unnecessary data interaction between nodes and increase the reliability, real-time and adaptability of the network.

Copper chalcogenides have a simple general formula, variable atomic ratios, and complicated crystal structures, which lead to their wealth of optical, electrical, and magnetic properties with great potential for wide applications ranging from energy conversion to the biomedical field. Herein, we summarize the recent advances in (1) the synthesis of size- and morphology tunable nanostructures by different methods; (2) surface modification and functionalization for different purposes; and (3) bioapplications for diagnosis and treatment of tumors by different imaging and therapy methods, as well as antibacterial applications. We also briefly discuss the future directions and challenges of copper chalcogenide nanoparticles in the biomedical field.

Weak interactions, non-uniformity and powdery assemblies limit the wide application of metal organic framework (MOF) in devices. Here we report a new strategy for area-selective assembly of MOF particles to prepare a thin film with the assistance of atomic layer deposition (ALD). Self-assembled hierarchically porous Fe-based MOF (PCN-333) films were formed on both flat and complex three-dimensional (3D) substrates by combining gas and liquid fabrication approaches, and can be precisely patterned with photolithography. We demonstrate that the PCN-333 film obtained possesses excellent electrochemical activity and can be applied in dopamine sensing for ultra-high sensitivity of 4637.78 µA mM−1 cm−2 with a wide linear range and a low limit of detection. Moreover, the PCN-333 film composite achieves a function of good selectivity of distinguishing dopamine and ascorbic acid. This strategy is promising to prepare MOF film-based on-chip devices with advanced functions.

Duo to their superior physicochemical properties, graphene and its derivatives (GDs), such as graphene oxide (GO) and reduced graphene oxide (rGO), have attracted extensive research interests around the world. In recent years, antibacterial activities of GDs have aroused wide concern and substantial works have been done. However, the underlying antibacterial mechanisms still remain controversial. Antibacterial activities of GDs vary with various factors, such as size, number of layers, oxygen-containing groups, and experimental surroundings. We assume that combination types between graphene oxide and substrate may affect the antibacterial activity. Therefore, in this work, GO was fixed on the titanium surface with three kinds of combination types including drop with gravitational effects (GO-D), electrostatic interaction (GO-APS) and electrophoretic deposition (GO-EPD), and the antibacterial activities in vitro were systematically investigated. Results showed that combination types affected the ability of GO for preventing Staphylococcus aureus (S. aureus) from gathering, sharpness of wrinkles or edges and reactive oxygen spices (ROS) levels. Once S. aureus are in the form of separation without aggregation, GO can effectively interact with them and kill them with sharp wrinkles or edges and high ROS levels. GO-EPD could effectively prevent S. aureus from gathering, own sharp wrinkles or edges and could generate higher ROS levels. As a result, GO-EPD exhibited optimal antibacterial activity against S. aureus, followed by GO-APS and GO-D., Graphical abstract Image 1, Highlights • Combination types between GO and substrate affect the ability of GO for preventing S. aureus from gathering. • Combination types between GO and substrate affect the ROS levels. • Once S. aureus are in the form of separation, GO can effectively interact with them and kill them.

Implant failure of titanium and its alloys still occurs due to insufficient osseointegration and implant associated infections. Therefore, titanium implants with enhanced osseointegration and antibacterial activities are desirable. To achieve this goal, graphene oxide (GO) as a dual zinc/magnesium (Zn/Mg) ion carrier and release platform was constructed on the titanium surface by cathode electrophoresis deposition. Rat bone mesenchymal stem cells were used to investigate the osteogenic activity. Gram-negative E. coli was utilized to assess the antibacterial activities. Results show that GO co-doped with Mg and Zn ions with a sustained and slow release exhibited the best osteogenic activity among all the samples by stimulating the expressions of osteogenesis related genes containing alkaline phosphatase (ALP), type I collagen (Col-I), osteocalcin (OCN), and osteopontin (OPN), and by promoting the alkaline phosphatase activity and extracellular matrix mineralization. The existence of GO endowed titanium with superior antibacterial activities against Gram-negative E. coli. Due to the synergistic effects of GO, Mg and Zn ions, a titanium surface with enhanced osseointegration and antibacterial activities was achieved.

As an important biomaterial, lactic acid (LA) widely exists in human blood and sweat. The development of enzyme-free LA sensors with high-sensitivity and low-cost remains a challenge. We present here a structure of Co-doped porous carbon film derived from zeolitic imidazolate framework-67 (ZIF-67) on 3D carbon frameworks through a pyrolysis process. The conformal coating of ZIF-67 film is realized by a combination of gas-phase and liquid phase growths with the assistance of an induction step from atomic layer deposited-ZnO nanomembrane. In the resultant hierarchical structure with large surface area, Co-doped porous carbon film is closely stacked and firmly attached to carbon skeleton to form Co-doped N-containing carbon framework (Co-NCF). Therein, the Co-doped porous carbon provides catalytic Co nanoparticle, while the carbon skeleton bridges the individual carbon nanoparticle to form a conductive pathway. When adopted as an enzyme-free LA sensor, the Co-NCF composite exhibits excellent electrochemical sensing property in terms of an ultrahigh sensitivity of 1108 μA mM-1cm−2 at a liner range from 0.1 to 1 mM with a limit of detection of 13.7 μM. This work, therefore, presents an efficient strategy to prepare porous carbon structures toward new electrode materials in promising biomedicine systems.

As the major pipeline for transporting oxygen and nutrients to living tissues, well‐ordered and functional vasculature is vital to maintain the function of organisms. The cerebrovascular disorders induced by acute or chronic diseases, including traumatic brain injury (TBI), stroke, and brain tumors, could cause vascular cognitive impairment and even mortality. Due to the complication of these cerebrovascular diseases, early diagnosis and monitoring their pathological processes in real time in animal models could enlighten us with insights into early prevention and effective treatment. Over the last decade, the NIR‐II fluorescence imaging technology has been well developed in both nanofluorophores and imaging systems. For cerebrovascular disorders, the collaborative use of wide‐field imaging setup with NIR‐II nanoprobes enable arteriovenous staging, and calculation of blood flow velocity to distinguish ischemic area in TBI and stroke. The changes in molecular and cellular levels of TBI provide the guidance on the design of targeted and activatable NIR‐II nanoprobes for evaluating and monitoring the microenvironment variations. For the brain tumors, both targeted strategy and focus ultrasound sonication are efficient approaches for overcoming the blood‐brain‐barrier and brain‐tumor‐barrier for delivery of nanoprobes. Therefore, NIR‐II fluorescence imaging‐guided surgical navigation of brain tumors and resected lesions biopsy intraoperatively ensure the accuracy of surgery based on the precise definition of tumor margins. This review summarizes the recent advances in NIR‐II fluorescence imaging technology, which is mainly inclusive of well‐developed NIR‐II nanofluorophores and their applications in cerebrovascular diseases with address of its challenges and great potential in these aspects.

With properties of complete degradation and favorable mechanical behavior, Mg and its alloys are regarded as the next generation medical metal materials. However, fast degradation and poor surface biocompatibility hinder their clinical applications. Inspired by the “petal effect”, we successfully constructed a superhydrophobic and highly adhesive coating on pure Mg via a simple hydrothermal treatment in a solution containing sodium oleate. The superhydrophobicity of the fabricated coating results from its flake-like micro-nanostructure and the low-surface-energy oleate group. Water droplet on the superhydrophobic coating cannot roll off even when the sample is turned upside down, owing to the sealed air-pockets and the van der Waals’ attraction at the solid-liquid interface, indicating a highly adhesive force. The chemical and mechanical stability of the superhydrophobic coating were measured. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements suggest enhanced corrosion resistance of the as-prepared sample. Furthermore, cell cytotoxicity, migration and adhesion data of human umbilical vein endothelial cells (HUVECs) reveal an improved cytocompatibility of the modified surface. Finally, hemolysis assay and platelet adhesion assay suggest an improved hemocompatibility. It is believed that the facile and low-cost method can expand the new application of superhydrophobic surface with highly adhesive on Mg in biomedical fields.

Graphene oxide has attracted widespread attention in the biomedical fields due to its excellent biocompatibility. Herein we investigated the layer-number dependent antibacterial and osteogenic behaviors of graphene oxide in biointerfaces. Graphene oxide with different layer numbers was deposited on the titanium surfaces by cathodal electrophoretic deposition with varied deposition voltages. The initial cell adhesion and spreading, cell proliferation, and osteogenic differentiation were observed from all the samples using rat bone mesenchymal stem cells. Both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were used to investigate the antibacterial effect of the modified titanium surfaces. Cocultures of human gingival fibroblasts (HGF) cells with Escherichia coli and Staphylococcus aureus were conducted to simulate the conditions of the clinical practice. The results show that the titanium surfaces with graphene oxide exhibited excellent antibacterial and osteogenic effects. Increasing the layer-number of graphene oxide resulted in the augment of reactive oxygen species levels and the wrinkling, which led to the antibacterial and osteogenic effects, respectively. Compared to pure titanium surface in the cells-bacteria coculture process, the modified titanium surfaces with graphene oxide exhibited higher surface coverage percentage of cells.

Titanium (Ti) has been widely used as orthopedic and dental implants, it is very important to improve the osteogenic activity and antibacterial ability of titanium implants. The objective of this work was to investigate the osteogenic and antibacterial ability of the zinc (Zn) ion implanted Ti at different implantation voltage. X-ray photoelectron spectroscopy results indicate that Zn was successfully implanted into titanium. Zn-implanted titanium surfaces exhibit enhanced cell proliferation ability, alkaline phosphatase (ALP) activity, and partial resistance to both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The excellent osteogenic and antibacterial ability are highly related to the implantation voltage. The cell proliferation and antibacterial ability can be enhanced by increasing the implantation voltage from 15 kV to 30 kV, indicating that Zn implantation at 30 kV is more beneficial to both osteogenic and antibacterial ability.

Mussel inspired polydopamine (PDA) coatings have attracted a great deal of attention for their superior osteogenic property. Furthermore, recent investigations have demonstrated that vessel formation is crucial to bone regeneration. Hence, in the present study, the potential ability of polydopamine coatings with different oxidation degrees were systematically investigated in vitro to improve the angiogenic behavior of human umbilical vein endothelial cells (HUVECs). PDA was first coated on titanium (PDA-1#), and then oxidized by thermal treatment at 150 (PDA-2#) and 300 °C (PDA-3#), respectively. X-ray photoelectron spectroscopy (XPS) results revealed that phenolic hydroxyl (C-OH) and primary amino group (-NH2) on PDA coatings deceased after oxidation, while quinone (C=O) increased. In vitro cell culture experiments suggested that PDA-2# sample was most beneficial for the adhesion, migration, and proliferation of HUVECs. Furthermore, HUVECs cultured on PDA-2# sample also exhibited best tube formation, CD31 expression, vascular endothelial growth factor (VEGF) secretion, as well as angiogenic-associated gene expression abilities. Our study suggests that moderate oxidation of PDA coating with balanced quinone and amino group has excellent potential to enhance bone vascularization, and is thus promising for clinical application in orthopedic implants.

The interactions between material surfaces and bacteria/cells have been widely investigated, based on which biomaterials with antibacterial and osteogenic abilities can be designed to conquer implant failures. The pH of environments is known to affect bacterial growth and bone formation/resorption, and it is possible that the antibacterial and osteogenic abilities of biomaterials can be simultaneously improved by regulating their surface alkalinity. Herein, we fabricated many kinds of films with various alkalinity levels on titanium surface to explore the effect of local alkaline microenvironments around material surfaces on the behaviors of bacteria and osteogenic cells. Both Gram-positive and -negative bacteria were cultured on sample surfaces to investigate their antibacterial effects. Cell adhesion, proliferation, and alkaline phosphatase (ALP) activities were investigated by culturing both bone mesenchymal stem cells (MSCs) and osteoblast cells on sample surfaces. The results show that an appropriate local alkaline environment can effectively inhibit the growth of both Gram-positive and -negative bacteria through inactivating ATP synthesis and inducing oxidative stress. Meanwhile, it can promote the osteogenic differentiation of bone MSCs and enhance the proliferation and ALP activities of osteoblast cells. In conclusion, material surfaces endowed with appropriate alkalinity can possess antibacterial and osteogenic properties, which provide a novel strategy to design multifunctional biomaterials for bone generation.

Nitrogen doped graphene quantum dots (N-GQDs) were synthesized to explore and extend their potential applications in biomedical field. The hemocompatibility and cytotoxity of the obtained N-GQDs were primarily assessed at concentrations ranging from 10 to 100 μg/ml. From the results, it was found that the proliferation of rat Bone Mesenchymal Stem Cells (rBMSCs) was depressed to a certain extent after incubating with the high concentration (100 μg/ml) of N-GQDs. The nanoscale size and superior dispersibility endow N-GQDs with good cell permeability. Meanwhile, owing to their intrinsic photoluminescence characteristic, the N-GQDs can be used to label cells with high uniformity and light stability in absence of chemical dyes. More importantly, the up-regulated expression of alkaline phosphate (ALP), extracellular matrix, osteopontin (OPN) and osteocalcin (OCN) in rBMSCs cultured with N-GQDs, indicating N-GQDs have the abilities to promote rBMSCs osteogenic differentiation. This work would help give a new insight into the advantages of N-GQDs and pave the way for application of N-GQDs in regenerative medicine fields.

Graphene halides are promising two-dimensional systems which have interesting physical and chemical properties. In particular, high quality fluorinated graphene offers a great potential in modulating variable properties by regulating its surface microstructure. Moreover, the fluorine introduction and carbon-fluorine bonding characters will enable some interesting biological response. Here, the biological responses to bacteria and cells of fluorinated graphene were studied. Present work revealed that partially fluorinated graphene behaved satisfactory antibacterial ability. Fluorinated graphene showed well facilitating function to cell adhesion in early period, however, after a longer incubation period, the enhanced intracellular ROS level in rBMSCs on the fully fluorinated graphene gives rise to the decrease of cell viability. It was found that there is no statistical difference in the activity of alkaline phosphatase (ALP) and matrix mineralization of rBMSCs on pristine graphene, partially fluorinated graphene and fluorographene. In addition, the introduction of fluorine into pristine graphene plane reduced the adhesion and aggregation of blood platelets due to the attenuation of π–π interaction between material surface and blood protein. The findings in this work revealed that partial fluorinated graphene exhibited better antibacterial ability and cytocompatibility, outperforming pristine graphene and fluorographene.

It is important to fabricate an implant possessing environment sensitive drug delivery. In this work, the construction of 3D porous structure on polyetheretherketone (PEEK) surface and pH sensitive polymer, chitosan, was introduced. The smart release of doxorubicin can be realized on the 3D porous surface of PEEK loading chitosan. We give a feasible explanation for the effect of chitosan on smart drug release according to Henderson-Hasselbalch equation. Furthermore, the intracellular drug content of the cell cultured on the samples with highest chitosan is significantly higher at pH 4.0, whereas lower at pH 7.4 than other samples. The smart release of doxorubicin via modification with chitosan onto 3D porous PEEK surface paves the way for the application of PEEK in drug loading platform for recovering bone defect caused by malignant bone tumor.

The efficacy of biomedical titanium implants mainly depends on their surface characteristics such as surface morphology, microstructure, and components, and the resulting performances. In this work, hierarchical hybrid micro/nanotip films incorporated with bioactive Sr2+/Mg2+ ions were prepared on a titanium surface by combining acid etching, hydrothermal treatment and a subsequent ion exchange process with Sr2+ and Mg2+ ions respectively. A Sr/Mg delivery platform is thus successfully obtained on a titanium surface and can allow for sustained release of Sr2+/Mg2+ ions at a slow rate for a period of time. In vitro SBF tests confirm that the Sr/Mg loaded titanate films possess good bioactivity accompanying the controlled release. Meanwhile, cell experiments further demonstrate that the Sr/Mg loaded micro/nanostructured titanium surfaces possess good biocompatibility and osteogenic activity. This is a successful attempt to apply an ion exchange technique to the surface modification of biomedical titanium materials and the strategy described here offers a general, facile, and straightforward chemical approach to functionalize various titanium-based material surfaces by constructing micro/nanostructures and using ion exchange with bioactive ions under mild synthetic conditions, and provides insight into the design of better biomedical implant surfaces for the future.

Neogambogic acid (NGA), an active ingredient in garcinia, can inhibit the growth of some solid tumors and result in an anticancer effect. We hypothesize that NGA may be responsible for the inhibition of proliferation of human breast cancer cell line MCF-7 cells. To investigate its anticancer mechanism in vitro, MCF-7 cells were treated with various concentrations of NGA. Results of MTT (methyl thiazolyl tetrazolum) assay showed that treatment with NGA significantly reduced the proliferation of MCF-7 cells in a dose-dependent manner. NGA could increase the expression of the apoptosis-related proteins FasL, caspase-3, caspase-8, caspase-9, and Bax and decrease the expression of anti-apoptotic protein Bcl-2 accompanied by the mitochondrial transmembrane damage. The antiproliferative effect of NGA on MCF-7 cells is due to the G(0)/G(1) arrest, increased apoptosis and activation of Fas/FasL and cytochrome C pathway. These results provide an important insight into the cellular and molecular mechanisms through which NGA impairs the proliferation of breast cancer cells.

NCEP/NCAR reanalysis data were used to characterize stratospheric temperature and water-vapor anomalies before and after the freezing rain and snow disaster of South China in 2008, and the influence of stratospheric circulation anomalies on the troposphere. Stratospheric temperature and water-vapor anomalies provided good leading indicators of this weather event. The period from December 1st 2007 to February 28th 2008 was divided into 18 pentads. During the 6th pentad, temperature decreased significantly at 10 hPa in the near-polar stratospheric region, and the decreasing trend strengthened and extended downward and southward to middle and lower latitudes. During the 14th-18th pentads, the temperature decrease reached its maximum and extended to 30°N. This coincided with the widespread freezing rain and snow event. By the end of January 2008, the temperature decrease ended in the near-polar stratospheric region, but continued in the mid-latitude area of the troposphere as the freezing rain and snow weather persisted. Similar to the temperature variations, positive anomalies of relative humidity in the stratospheric near-polar region also strengthened and extended downward and southward, coinciding with the freezing rain and snow event. Along with the significant relationship between the freezing rain and snow disaster and stratospheric circulation anomalies, the stratospheric polar vortex changed its shape in late December, intensifying and spreading downward from the top of the stratosphere and southward to the Asian continent, resulting in a deepening of the East Asian Trough and a strengthening of meridional circulation. Before the occurrence of the freezing rain and snow event, temperature and vapor increases in the stratosphere transferred downward to the troposphere, along with a stratospheric flow in the near-polar region southward to lower latitudes.

From the perspective of surface modification of biomaterials, graphene is very promising because of its unique physical and chemical properties. Herein, we report direct in situ fabrication of graphene on nitinol (NiTi) shape memory alloy by chemical vapor deposition (CVD) and investigate both the growth mechanism as well as surface bioactivity of the modified alloy. Growth of the graphene layer is independent of Ni but is rather correlated with the formation of the TiC phase on the surface. Graphene nucleates and grows on this carbide layer during exposure to CH4. The graphene layer is observed to promote the osteogenesis differentiation of mesenchymal stem cells and surface bioactivity. The use of graphene as a bioactive layer is a viable approach to improving the surface properties of NiTi-based dental and orthopedic implants and components.

Nitinol is widely fabricated as stents for the palliation treatment of many kinds of cancers. It is of great importance to develop nitinol stents with selective tumor cell inhibition effects. In this work, a series of pH sensitive films composed of Ni(OH)2 and Ni-Ti layered double hydroxide (Ni-Ti LDH) with different Ni/Ti ratios were prepared on the surface of nitinol via hydrothermal treatment. The films with specific Ni/Ti ratios would release a large amount of nickel ions under acidic environments but were relatively stable in neutral or weak alkaline medium. Cell viability tests showed that the films can effectively inhibit the growth of cancer cells but have little adverse effects to normal cells. Besides, extraordinarily high intracellular nickel content and reactive oxygen species (ROS) level were found in cancer cells, indicating the death of cancer cells may be induced by the excessive intake of nickel ions. Such selective cancer cell inhibition effect of the films is supposed to relate with the reversed pH gradients of tumor cells.

Quinoline and N-methyl quinolinium-substituted nitronyl nitroxides 1 and 2 were prepared, and their crystal structures were determined. Thermal variance of their molar magnetic susceptibilities was measured with SQUID, and the results indicated that they both showed antiferromagnetic behavior. Atomic spin density in 1 and 2 was calculated with ab initio method, and magneto-structural correlation was discussed.