Search

For a long time, lumbar pedicle screw fixation and fusion has been regarded as the gold standard for the treatment of the lumbar spine degenerative diseases. However, in patients with osteoporosis, pedicle screw fixation often fails to obtain long-term satisfactory. In recent years, the emergence of cortical bone trajectory screw has become an alternative option for dealing with these problems. With the development of clinical and basic research, scholars have found that cortical bone screw internal fixation can help improve fixation strength, reduce surgical trauma, and accelerate postoperative recovery. Based on the current evidence-based research and clinical application experience, this article analyzes the research hotspots of cortical bone screws, introduces the experience and pitfalls in clinical practice, and provides references for colleagues.一直以来，椎弓根螺钉内固定腰椎融合术都被认为是腰椎退行性疾病治疗的金标准，但在合并骨质疏松的患者中，该术式常不能使患者获得长期满意的结果。近年来，皮质骨轨迹螺钉的出现成为了处理这些问题的另一种选择。随着临床与基础研究的深入，学者发现皮质骨螺钉内固定有助于提高固定强度、降低手术创伤、加速术后康复。本文基于目前的循证研究与临床应用体会，分析皮质骨螺钉的研究热点问题，介绍临床实践中的体会，为同道提供参考。.

We present continuum extrapolated results of charmonium and bottomonium correlators in the vector channel at several temperatures below and above $T_c$. The continuum extrapolation jointly performed with the interpolations to have physical values of $J/\psi$ and $\Upsilon$ masses in the confined phase is based on calculations on several large quenched isotropic lattices using clover-improved Wilson valence fermions carrying different quark masses. The extrapolated lattice correlators are confronted with perturbation theory results incorporating resummed thermal effects around the threshold from pNRQCD and vacuum asymptotics above the threshold. An additional transport peak is modelled below the threshold allowing for an estimate of the diffusion coefficients for charm and bottom quarks. We find that charmonium correlators in the vector channel can be well reproduced by perturbative spectral functions above $T_c$ where no resonance peaks for $J/\psi$ are needed at and above 1.1 $T_c$, while for bottomonium correlators a resonance peak for $\Upsilon$ is still needed up to 1.5 $T_c$. By analyzing the transport contribution to the correlators we find that the drag coefficient of a charm quark is larger than that of a bottom quark., Comment: published version

Aims: To characterize a robust NAD+-dependent formate dehydrogenase firstly obtained from a nonmethylotroph, Bacillus sp. F1. Methods and Results: The Bacillus sp. F1 NAD+-dependent formate dehydrogenase (BacFDH) gene was cloned by TAIL-PCR and heterologous expressed in Escherichia coli. BacFDH was stable at temperatures below 55°C, and the half-life at 60°C was determined as 52·9 min. This enzyme also showed a broad pH stability and retained more than 80% of the activities after incubating in buffers with different pH ranging from 4·5 to 10·5 for 1 h. The activity of BacFDH was significantly enhanced by some metal ions. Moreover, BacFDH exhibited high tolerance to 20% dimethyl sulfoxide, 60% acetone, 10% methanol, 20% ethanol, 60% isopropanol and 20% n-hexane. Like other FDHs, BacFDH displayed strict substrate specificity for formate. Conclusion: We isolated a robust formate dehydrogenase, designated as BacFDH, which showed excellent thermal stability, organic solvent stability and a broad pH stability. Significance and Impact of the Study: The multi-aspect stability makes BacFDH a competitive candidate for coenzyme regeneration in practical applications of chiral chemicals and pharmaceuticals synthesis with a relatively low cost, especially for the catalysis performed in extreme pH conditions and organic solvents.

The energy loss of heavy quarks in a quark-gluon plasma of finite size is studied within the light-cone integral approach. A simple analytical formulation of the radiative energy loss of heavy quarks is derived. This provides a convenient way to quantitatively estimate the quark energy loss. Our results show that if the energy of a heavy quark is much larger than its mass, the radiative energy loss approaches the radiative energy loss of light quarks., 4 pages, 2 figures. Accepted for publication in European Physical Journal A

Three bacterial strains, Arthrobacter sp. NB1, Serratia sp. NB2 and Stenotrophomonas sp. NB3, were isolated from contaminated sludge by using nitrobenzene as a sole source of carbon and nitrogen. It was observed that all three strains could degrade nitrobenzene at 400 mg/L initial concentration and mixed-cultivation of these strains could enhance the degradation of nitrobenzene compared with mono-cultivation. Mixture design was used for adjusting the proportions of each strain and the optimal ratio of inoculation size was NB1:NB2:NB3 = 4:4:5, where the nitrobenzene degradation percentage was two times higher than for by the single strain. The results of Plackett-Burman design indicated that Mg2+, Ca2+, Fe2+, Zn2+ and Mn2+ had a positive effect on the degradation of nitrobenzene, while Cu2+ and Co2+ had a negative effect on it.

This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held from May 14th to June 10th 2007., LaTeX, 185 pages, uses iop styles; writeup of the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held from May 14th to June 10th 2007

Current models of the multistep adhesion cascade for leukocyte-endothelial interactions predict loss of L-selectin from the leukocyte surface before transendothelial migration. We have tested this hypothesis using in vitro adhesion and transendothelial migration assays and a zinc-dependent metalloproteinase inhibitor, Ro 31-9790 (N-2-((2s)-[(hydroxycarbamoyl)methyl)-4-methylvaleryl]-N-1,3 -dimethyl-L-valinamide), which prevents chemoattractant-induced (e.g., IL-8, FMLP, C5a, platelet-activating factor) L-selectin endoproteolytic cleavage from isolated human neutrophils. Inhibitor and vehicle-treated neutrophils exhibited identical behavior during both adhesive interactions with 4- and 24-h TNF-alpha-activated HUVEC monolayers under flow, (including rate of initial attachment, rolling velocities, stable adhesion, and transmigration) and in static adhesion assays. Flow cytometric analysis of transmigrated neutrophils with mAb to L-selectin revealed that vehicle treated neutrophils had minimal detectable surface L-selectin, whereas inhibitor-treated neutrophils retained comparable levels of L-selectin on their surface as neutrophils maintained at 37 degrees C. In addition, mAb to L-selectin that induce rapid shape change and homotypic adhesion (LAM1-116) did not enhance the rate or extent of neutrophil transmigration under flow or static conditions. Neutrophils preincubated with LAM 1-116 displayed similar behavior to neutrophils preincubated with the control anti-L-selectin mAb, LAM1-101. In summary, these results demonstrate that there is no requirement for L-selectin to be shed from the surface of neutrophils before, or during, their migration across endothelial monolayers, and that prevention of surface L-selectin proteolytic cleavage does not enhance or inhibit neutrophil-endothelial cell adhesive interactions.

We discuss lattice calculations of quark number susceptibilities and the free energy of a static quark anti-quark pair in 2+1 flavor QCD at high temperatures using the HISQ action. We compare our lattice calculations with perturbative results.

Based on Conesa del Valle et al (2008 Phys. Lett. B 663 202), we present the results for the nuclear modification factors RAA and RCP of the high transverse momentum (5 < pt < 60 GeV/c) distribution of muons in Pb–Pb collisions at LHC energies, in which two pseudo-rapidity ranges covered by the LHC experiments, |η| < 2.5 and 2.5 < η < 4, are investigated. Heavy-quark energy loss is taken into account by mass-dependent BDMPS quenching weights. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon pt distribution above a few GeV/c. The muons from W and Z, that dominates the high pt, can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks.