Tailoring MSx Quantum Dots (M = Co, Ni, Cu, Zn) for Advanced Energy Storage Materials with Strong Interfacial Engineering.

Metal sulfides, as vital members of electrodes materials, still suffer from serious volume expansion and polysulfides shuttling. Herein, through inexpensive and high efficiency chemical-bonding/hydrophobic-association methods, a series of metal-sulfides quantum dots (QDs) with large-scale synthesis (≈100 g) is successfully prepared, further forming low-dimensional composites with high redox activity. For the derived electrodes samples, with the increasing of outer electron numbers (Co2+ /Ni2+ /Cu2+ /Zn2+ ), interfacial coupling is significantly modified. Among them, nanoscale ZnS@double carbon with rich interfacial Zn-O/S-C bonds displays remarkable electrochemical activity, with the capacity of ≈1000 mAh g-1 after 100 loops. Through tailoring double carbons and interfacial merits, in situ sulfur formation is stabilized, and the cycling stability of Zn-based samples can increase up to 4000 cycles. Even at 5.0 A g-1 after 1500 cycles, the full-cells capacity can reach up to ≈380 mAh g-1 . Supported by detailed kinetic analysis and ex situ technologies, the enhanced interfacial capacitances and ions moving are confirmed for the improved electrochemical properties. Given this, the work is expected to boost future developments of mineral processing, and QDs preparation, whilst providing effective strategies for advanced electrode materials.

Designing Hollow Carbon Sphere with Hierarchal Porous for Na-S Systems with Ultra-Long Cycling Stabilities.

Captured by the low-cost and high theoretical specific capacity, Na-S systems have garnered much attention. However, their intermediate products (dissolved polysulfide) are always out of control. Considering the excellent space confinements and conductivity, they have been regarded as promising candidates. Herein, the hollow spheres with suitable thickness shell (~20 nm) are designed as hosting materials, accompanied by in-depth complexing. Benefitting from the abundant micro-pores (mainly about conical-type and slits-type pores < 1.0 nm), the active S4 molecules are successfully filled in the pores through vacuum tube sealing technology, effectively avoiding the process from solid S8 to liquid Na2S6. As cathode for Na-S systems, their capacity could remain at 920 mAh g−1 at 0.1 C after 100 cycles. Even at 10.0 C, the capacity still remained at about 310 mAh g−1 after 7000 cycles. Supported by the detailed kinetic behaviors, the improvement of ions diffusion behaviors is noted, bringing about the effective thorough redox reactions. Moreover, the enhanced surface-controlling behaviors further induces the evolution of rate properties. Therefore, their stable phase changing is further confirmed through in situ resistances. Thus, the work is anticipated to offer significant design for hosting carbon materials and complexing manners.

A novel serine hydroxymethyltransferase from Arthrobacter nicotianae: characterization and improving catalytic efficiency by rational design.

BACKGROUND: Serine hydroxymethyltransferase (SHMT) is the key enzyme in L-serine enzymatic production, suggesting the importance of obtaining a SHMT with high activity. RESULTS: Here, a novel SHMT gene, glyA, was obtained through degenerate oligonucleotide-primed PCR and encoded a novel SHMT with 54.3% similarity to the known SHMT from Escherichia coli. The obtained protein AnSHMT showed the optimal activity at 40 °C and pH 7.5, and was more stable in weakly alkali conditions (pH 6.5-8.5) than Hyphomicrobium methylovorum's SHMT (pH 6.0-7.5), In order to improve the catalytic efficiency of the wild type, the site-directed mutagenesis based on sequences alignment and bioinformatics prediction, was used and the catalytic efficiency of the mutant I249L was found to be 2.78-fold higher than that of the wild-type, with the replacement of isoleucine by leucine at the 249 position. CONCLUSIONS: This research provides useful information about the interesting site, and the application of DOP-PCR in cloning a novel glyA gene.

Effect of growth factors (BMP-4/7 & bFGF) on proliferation & osteogenic differentiation of bone marrow stromal cells.

BACKGROUND & OBJECTIVES: BMP (bone morphogenetic protein)-4/7 and bFGF (basic fibroblast growth factor) significantly promote the osteogenic activity and the proliferation of rabbit BMSCs (bone marrow stromal cells), respectively. However, their synergistic effects on the proliferation and the differentiation of BMSCs remain unclear. In the present study, the effects of bFGF and BMP-4/7 were investigated on the proliferation and the differentiation of rat BMSCs in vitro. METHODS: BMSCs were isolated from New Zealand white rabbits and cultured to the third passage. The samples were divided into five groups according to the material implanted: (A) 80 ng/ml BMP-4/7; (B) 80 ng/ml bFGF; (C) 30 ng/ml BMP-4/7 and 30 ng/ml bFGF; (D) 50 ng/ml BMP-4/7 and 50 ng/ml bFGF; and (E) 80 ng/ml BMP-4/7 and 80 ng/ml bFGF. Cell proliferation was analyzed using methyl thiazolyl tetrazolium (MTT) assay. Alkaline phosphatase activity and osteocalcin (OC) dynamics were also measured. RESULTS: BMP-4/7 alone significantly (P<0.05) promoted the proliferation of BMSCs. At the same time, it also promoted or inhibited the osteogenic differentiation of BMSCs. The synergistic effects of BMP-4/7 and bFGF significantly promoted both the proliferation and the osteogenic differentiation of BMSCs. The treatment of the synergistic effects was dose and time dependent. INTERPRETATION & CONCLUSIONS: A rational combination of BMP-4/7 and bFGF can promote the proliferation and the osteogenic differentiation of BMSCs. In addition, the synergistic functions are effective.

Designing Sphere-like FeSe2-Carbon Composites with Rational Construction of Interfacial Traits towards Considerable Sodium-storage Capabilities.

Due to their low cost and high stability, sodium-ion batteries have been increasingly studied. However, their further development is limited by the relative energy density, resulting in the search for high-capacity anodes. FeSe2 displays high conductivity and capacity but still suffers from sluggish kinetics and serious volume expansion. Herein, through sacrificial template methods, a series of sphere-like FeSe2-carbon composites are successfully prepared, displaying uniform carbon coatings and interfacial chemical FeOC bonds. Moreover, benefiting from the unique traits of precursor and acid treatment, rich structural voids are prepared, effectively alleviating volume expansion. Utilized as anodes of sodium-ion batteries, the optimized sample displays considerable capacity, achieving 462.9 mAh g-1, with 88.75% coulombic efficiency at 1.0 A g-1. Even at 5.0 A g-1, their capacity can be kept at approximately 318.8 mAh g-1, while the stable cycling can be prolonged to 200 cycles above. Supported by the detailed kinetic analysis, it can be noted that the existing chemical bonds facilitate the fast shuttling of ions at the interface, and the enhanced surface/near-surface properties are further vitrified. Given this, the work is expected to offer valuable insights for the rational design of metal-based samples toward advanced sodium-storage materials.

Controlling of Ni-Based Composites in Salt Melt Synthesis with High Sodium-Ion Storage Performance.

Owing to its fascinating properties (such as high theoretical specific capacity and considerable conductivity), nickel sulfide (NiS) was investigated comprehensively as an anode material in sodium-ion batteries. However, they still suffered from volume expansion and sluggish kinetics, resulting in serious cycle capabilities. Herein, through controlling the kind of molten salts (Na2SO4, NaCl, and Na2CO3) in salt melt synthesis (SMS), a series of NiS with an N, S-codoped carbon layer was successfully prepared, accompanied with different morphologies and structures (earthworm-like belts and triangular and spherical particles). Tailored by the ionic strength and viscosity of molten salts, the as-prepared samples displayed different crystallization behaviors, bringing about a difference in electrochemical performance. As earthworm-like NiS@C was explored as an anode material for SIBs, an initial capacity of 712.5 mAh g-1 at 0.5 A g-1 could be obtained, and it still kept 527.4 mAh g-1 after 100 cycles. Even at 2.0 A g-1, a capacity of 508.6 mAh g-1 could be achieved. Meanwhile, with the assistance of detailed kinetic analysis, the rapid diffusion behaviors of Na+ and redox reaction mechanisms of as-fabricated samples were proven for the enhanced electrochemical properties. Given this, this work is expected to provide a method for designing the morphology and structure of metal sulfides, while shedding light on the orientation of fabricating advanced electrode materials for SIBs.

Recombinant BMP 4/7 fusion protein induces differentiation of bone marrow stem cells.

Bone morphogenetic proteins (BMPs) induce differentiation of mesenchymal cells to cartilage and bone. We cloned BMP4 and BMP7 cDNAs from human placenta and fetal cartilage cells, respectively, and used an Escherichia coli expression system to produce recombinant BMP4 and BMP4/7 proteins. Differentiation of primary cultures of bone marrow stem cells (BMSC) treated with BMP4 or BMP4/7 was evaluated by Von Kossa staining and by determining alkaline phosphatase activity and osteocalcin level. BMP4/7-induced BMSC differentiation more potently than BMP4. We showed that BMP4/7 fusion protein expressed in E. coli is biologically active and is a novel strategy to treat bone injury in a clinical setting.

Silencing of HMGA1 expression by RNA interference suppresses growth of osteogenic sarcoma.

The expression of high mobility group protein A1 (HMGA1) protein has been closely related to various malignant and prognostic degrees of tumor. To investigate the influence of down-regulating HMGA1 on the tumor and the mechanism underlying antitumor of HMGA1, we transfected the HMGA1 shRNA vector into the osteogenic sarcoma MG-63 cell and observed the changes of cell proliferation, invasion abilities, and the tumor growth. HMGA1 gene expression could be efficiently inhibited, and cell proliferation, migration, invasion, and matrix metalloprotease level were also decreased. BALB/C nude mice injected with the MG-63 cells transfected HMGA1 shRNA showed the significant lower tumor weight, tumor volume, and longer tumor-forming time compared with the control group. Our results suggest that knockdown of HMGA1 could inhibit growth and metastasis potentials of MG-63 cells, which may be a therapeutic target protein for osteogenic sarcoma and may be of biological importance.

Peiminine Induces G0/G1-Phase Arrest, Apoptosis, and Autophagy via the ROS/JNK Signaling Pathway in Human Osteosarcoma Cells in Vitro and in Vivo.

Aims: Peiminine has been reported to have various pharmacological properties, including anticancer activity. In this study, we investigated the effect of this alkaloid on osteosarcoma and explored the underlying mechanisms. Methods: To evaluate the antiosteosarcoma effects of peiminine in vitro, cell viability was assessed by CCK-8 and live/dead assays; the effects of the drug on apoptosis and the cell cycle were examined by flow cytometry; the effects on cell migration and invasion were detected by wound healing and Transwell assays, respectively, while its effects on autophagy were observed by transmission electron microscopy and an LC3 fluorescent puncta formation assay. The role of autophagy in the peiminine-mediated effects in osteosarcoma cells was evaluated by CCK-8 assay and western blotting after the application of the autophagy inhibitor chloroquine. The effect of peiminine on reactive oxygen species (ROS) production was analyzed using fluorescence confocal microscopy and spectrophotometry. Additionally, peiminine-treated osteosarcoma cells were exposed to SP600125, a JNK inhibitor, and N-acetylcysteine, a ROS scavenger, after which the contribution of the ROS/JNK signaling pathway to osteosarcoma was assessed using cell viability and LC3 fluorescent puncta formation assays, flow cytometry, and western blotting. A xenograft mouse model of osteosarcoma was generated to determine the antitumor effects of peiminine in vivo. Results: Peiminine suppressed proliferation and metastasis and induced cell cycle arrest, apoptosis, and autophagy in osteosarcoma cells. These anticancer effects of peiminine were found to be dependent on intracellular ROS generation and activation of the JNK pathway. In line with these results, peiminine significantly inhibited xenograft tumor growth in vivo. Conclusions: Peiminine induced G0/G1-phase arrest, apoptosis, and autophagy in human osteosarcoma cells via the ROS/JNK signaling pathway both in vitro and in vivo. Our study may provide an experimental basis for the evaluation of peiminine as an alternative drug for the treatment of osteosarcoma.

Non­covalent proteasome inhibitor PI­1840 induces apoptosis and autophagy in osteosarcoma cells.

Osteosarcoma (OS) is the predominant form of primary bone malignancy in children and adolescents. Although the combination of chemotherapy and modified surgical therapy leads to marked improvements in the survival rate, the therapeutic outcomes remain unsatisfactory. Therefore, the identification of novel drugs with higher efficacy and fewer side­effects is urgently required. Proteasome inhibitors have been approved by the Food and Drug Administration (FDA) for the treatment of certain cancers, although none of them are directed against OS. Non­covalent proteasome inhibitors, such as PI­1840, are superior to covalent ones in numerous respects in view of their chemical structure; however, to date, no studies have been published on the effects of non­covalent proteasome inhibitors on OS cells. In the present study, the antineoplastic effects of PI­1840 were systematically evaluated in the OS cell lines, MG­63 and U2­OS. Cell viability and morphological changes were assessed by Cell Counting Kit­8 (CCK­8) and live/dead assays. The cell cycle was analyzed using flow cytometry (FCM) and western blot analysis (assessing the levels of the proteins p21, p27, and the tyrosine kinase, WEE1). The extent of cell apoptosis and autophagy were assessed by FCM, western blot analysis [of the apoptosis­associated proteins, microtubule­associated protein 1 light chain 3 α (LC3) and Beclin1], and mRFP­GFP­LC3 adenovirus transfection assay. Transwell and wound healing assays, and western blot analysis of the matrix metalloproteinases (MMPs)2 and 9 were performed to preliminarily evaluate the migration and invasion capability of the cells. In the present study, our results revealed that PI­1840 inhibited the proliferation of OS cells and induced apoptosis, partly due to attenuation of the nuclear factor­κB (NF­κB) pathway. In addition, PI­1840­induced autophagy was detected, and inhibiting the autophagy of the OS cells led to an increase in the survival rate of the U2­OS cells rather than of the MG­63 cells. Furthermore, PI­1840 attenuated the migration and invasion capabilities of the OS cells. In conclusion, the present study revealed PI­1840 to be a promising drug for the treatment of OS.

Biomechanical effects of pedicle screw adjustments on the thoracolumbar burst fractures.

BACKGROUND: Posterior pedicle screw device is widely used in treatment of thoracolumbar burst fractures. As the clinical operation is not based upon quantitative data of adjustments, the results are not optimal. At present, no study has assessed the associations between the device adjustments and the restoration of stiffness. We investigated the biomechanical effects that adjustments of a pedicle screw device had on the burst fracture, and explored an optimal adjustment. METHODS: Burst fractures were produced at L1 vertebra in 24 fresh calf spines (T12-L3). The specimens were divided into four groups at random. Pedicle screw devices were attached to T13 and L2. Four device adjustments, consisting of distraction and extension, were applied. Adjustment 1 was pure 6° extension, adjustment 2 was pure 5 mm distraction, adjustment 3 was 6° extension followed by 5 mm distraction, and adjustment 4 was 5 mm distraction followed by 6° extension. The effect of each adjustment on the stiffness restoration, anatomical reduction, and neural decompression for the burst fractures was analyzed and evaluated. RESULTS: Pure extension (Group 1) produced the closest segment height and the least restoration of the canal to the intact. Pure distraction (Group 2) restored stiffness most, but with only 60% stiffness of the intact value, and lost the segmental angle most to the intact. The combination of extension-distraction (Group 3 and Group 4) produced the maximum reduction of the anatomy and restoration of the canal in the burst fracture, and the least stiffness restoration. The sequence of extension and distraction did not affect stiffness restoration, anatomical reduction, and neural decompression. CONCLUSIONS: The device adjustments affected stiffness restoration, anatomical reduction, and neural decompression. The combined extension-distraction adjustment may be the most suitable considering the anatomical reduction and neural decompression, but the stiffness decreased the most; it should be considered to reconstruct L1 vertebra.

Effect of recombinant adeno-associated BMP-4/7 fusion gene on the biology of BMSCs.

The aim of the study was to investigate the effect of recombinant adeno-associated virus (AAV) with morphogenetic protein 4/7 fusion gene on the ossification of rabbit bone marrow stromal cells (BMSCs). The genes BMP-4 and BMP-7 were obtained through one-step reverse transcriptase polymerase chain reaction from human placental cells. The BMP-4/7 fusion gene was generated through recombination. The rabbit BMSCs were transfected with the recombinant AAV vectors carrying AAV-BMP-4/7 with various multiplicity of infection (MOI) values. Expression of fusion gene BMP-4/7 protein was determined by the ELISA method. The ossification of cells was evaluated by observing alkaline phosphatase (ALP) and osteocalcin (OC) activity after transfection for 7 and 14 days. We successfully constructed the recombinant AAV with the BMP-4/7 fusion gene. A 29-20 kDa protein was shown by SDS-PAGE electrophoresis following transfection with AAV-BMP-4/7. The fusion protein BMP-4/7 in BMSCs transferred by AAV showed a positive correlation with various MOI values. There was significantly higher ALP and OC activity in the AAV-BMP-4/7 transfection groups than in the AAV-EGFP groups (t(ALP)=896.88, P<0.001, t(OC)=543.24, P<0.01). The fusion gene BMP-4/7 is capable of enhancing the expression of BMPs and possesses significant ossification activity through AAV.

[A comparative study of anterior decompression approach by using cervical retractor systems and traditional surgical approach to treat cervical spondylosis].

OBJECTIVE: To compare and evaluate the whole effect of anterior decompression approach to treat cervical spondylotic myelopathy by using cervical retractor systems and the traditional surgical approach. METHODS: From April 2001 to August 2004, group A included 30 males and 23 females aging from 31 to 69 years, and the involved time was from 7 months to 15 years. Involved segments included 22 one-segments, 24 two-segments and 7 three-segments. In all 53 cases, anterior windowing decompression and fusion with autograft and titanium plate internal fixation by using traditional circular saw were performed. Group B included 48 males and 20 females aging from 33 to 74 years, and the involved time was from 5 months to 18 years. Involved segments included 23 one-segments, 34 two-segments and 11 three-segments. In all 68 cases, anterior undermined far-reaching decompression and fusion with autograft and titanium plate internal fixation by using removing disc merely in the single-level or separately in the multilevels employing self-retractor and Caspar cervical retractor systems via interspinal approach were performed. X-rays and MRI showed cervical disc degeneration, herniation and spinal cord compression. The surgery time, loss of blood, vertebral body fusion time, difference in height of involved segments pre- or postoperatively and complications were counted up and compared between the two groups. Improvement rate of spinal function pre- or postoperatively were valued by using JOA score. RESULTS: A total of 92 cases including 42 of group A and 50 of group B were followed up for 3 to 5 years, mean 3.5 years. In group A, surgery time, loss of blood, time of vertebral body fusion, difference in height of involved segments pre- or postoperatively, and improvement ratio of spinal function were (76.80 +/- 28.41) min, (564.00 +/- 181.96) mL, (12.10 +/- 3.58) weeks, (1.30 +/- 0.67) mm and 0.49% +/- 0.14%, respectively. In group B, they were (57.90 +/- 15.01) min, (317.50 +/- 136.92) mL, (9.75 +/- 1.36) weeks, (3.00 +/- 0.56) mm and 0.71% +/- 0.17%, respectively. The differences between the two groups were significant in all measured values (P < 0.05). Complications occurred in 7 cases of group A including 1 spinal cord injury, 1 plate displacement, 1 bonegraft displacement and 4 disfunctions of iliac region. No complication happened in group B. CONCLUSION: Anterior decompression approach using cervical retractor systems is significantly superior to the traditional approach as to the whole effect to treat cervical spondylotic myelopathy, and further perfects the traditional anterior decompression approach. The modified approach is scientific, safe and easily spread.