MORGAN第六代高速线材生产线的日修周修制

代表当今世界高线设备最高水平的MORGAN第六代高速线材轧机以其高速、高自动化、高效而闻名于世,如何在设备引进后用好、管好,并使之产生良好效益是摆在人们面前的一大难题。本文阐述在实践中如何成功地深化应用日修、周修制,通过抓设备管理工作,促进生产,力争达到“零故障”目标并产生明显经济效益。

Optimal quasi-periodic maintenance policies for two-unit series system

To investigate the effects of various random factors on the preventive maintenance （PM） decision-making of one type of two-unit series system, an optimal quasi-periodic PM policy is introduced. Assume that PM is perfect for unit 1 and only mechanical service for unit 2 in the model. PM activity is randomly performed according to a dynamic PM plan distributed in each implementation period. A replacement is determined based on the competing results of unplanned and planned replacements. The unplanned replacement is trigged by a catastrophic failure of unit 2, and the planned replacement is executed when the PM number reaches the threshold N. Through modeling and analysis, a solution algorithm for an optimal implementation period and the PM number is given, and optimal process and parametric sensitivity are provided by a numerical example. Results show that the implementation period should be decreased as soon as possible under the condition of meeting the needs of practice, which can increase mean operating time and decrease the long-run cost rate.

“还给中国一个公道”──一位剧作家的心愿

“还给中国一个公道”──一位剧作家的心愿周兴亚本文作者（左）、剧作家周修（右）与本刊主编合影一、本世纪四十年代初，在法西斯匪邦横行全球疯狂摧残人类文明的血腥岁月，在中华民族历经了近百年沦为半殖民地的深重劫难之后正奋起在东方为抗日救亡和保卫人类文明而浴...

Availability-based maintenance optimization under unequal inspection period and imperfect repair

Taking the multi-component system as research object, a maintenance optimization model based on the unequal inspection period and imperfect repair is established by considering the requirement of expected availability for improving the system＇s availability. An age reduction factor is used to describe the effect of imperfect repair, and the modelling approach for the unequal inspection period is proposed. Unavailable situations are classified into three kinds of independent cases, and the availability is calculated accordingly. Based on the analysis of the relationship between the unavailable cases and the unequal inspection period, an optimization model under imperfect repair is established to optimize the system＇s expected availability. A case study of a wind turbine is provided, and three key components, i.e. gearbox, generator and spindle, are considered. The optimization results of the unequal inspection period model and the equal inspection period model are compared. The results show that the unequal inspection period model based on availability can update the maintenance plan so as to optimize maintenance activities and improve the system＇s availability.

Peripheral nerve repair by conduits made of human hair keratin: An experimental study

Objective: To explore the method to repair injured peripheral nerve using conduits made of human hair keratin (HHK). Methods: The tibial nerves of rabbits were transected leaving a gap 10 mm in length between the 2 severed ends, which were either routinely sutured or bridged using HHK nerve conduits. Electro-physiological , anatomical and histological examinations were performed at different time postoperatively. Results: Electrophysiological study showed more obvious improvement in the neural function recovery in rabbits with HHK conduits bridging as compared with that in rabbits with routine suture. In the former group, HHK conduits were gradually degraded and absorbed with large amount of myelinated nerve fibers and Schwann cells regenerated around HHK conduits. In the latter group, however, the nerve tissues around the suture were degenerated and replaced by connective tissues. Conclusion: HHK may induce the regeneration of the nerve fibers and provides an ideal approach to repair nerve damages.

New Explicit Exact Solutions for the （2＋1）-Dimensional Higher-Order Broer-Kaup System

Using the modified extended tanh-function method,explicit and exact traveling wave solutions for the(2+1)-dimensional higher-order Broer-Kaup(HBK)system,comprising new soliton-like and period-form solutions,are obtained.

BNIP3 is essential for mediating 6-thioguanine- and 5-fluorouracil-induced autophagy following DNA mismatch repair processing

DNA mismatch repair （MMR） processes the chemically induced mispairs following treatment with clinically important nucleoside analogs such as 6-thioguanine （6-TG） and 5-fluorouracil （5-FU）. MMR processing of these drugs has been implicated in activation of a prolonged G2/M cell cycle arrest for repair and later induction of apoptosis and/or autophagy for irreparable DNA damage. In this study, we investigated the role of Bcl2 and adenovirus EIB Nineteen-kilodalton Interacting Protein （BNIP3） in the activation of autophagy, and the temporal relationship between a G2/M cell cycle arrest and the activation of BNIP3-mediated autophagy following MMR processing of 6-TG and 5-FU. We found that BNIP3 protein levels are upregulated in a MLHI （MMR＋）-dependent manner following 6-TG and 5-FU treatment. Subsequent small-interfering RNA （siRNA）-mediated BNIP3 knockdown abrogates 6-TG- induced autophagy. We also found that p53 knockdown or inhibition of mTOR activity by rapamycin cotreatment impairs 6-TG- and 5-FU-induced upregulation of BNIP3 protein levels and autophagy. Furthermore, suppression of Checkpoint kinase 1 （Chkl） expression with a subsequent reduction in 6-TG-induced G2/M cell cycle arrest by Chkl siRNA promotes the extent of 6-TG-induced autophagy. These findings suggest that BNIP3 mediates 6-TG- and 5-FU-induced autophagy in a p53- and mTOR-dependent manner. Additionally, the duration of Chkl-activated G2/ M cell cycle arrest determines the level of autophagy following MMR processing of these nucleoside analogs.

Periodic Solutions of Singular Neutral Differential Systems with Infinite Delay

In this paper,we discuss the periodic solutions of the nonlinear singular neutral differential systems with infinite delay.By using matrix measure and Krasnoselskii＇s fixed point theorem,we obtained the suffcient conditions of the existence of periodic solutions.

Small ubiquitin-related modifier paralogs are indispensable but functionally redundant during early development of zebrafish

The Small ubiquitin-related modifier （SUMO） conjugation to a variety of proteins regulates diverse cellular processes, including transcription, cell cycle regulation and maintenance of genome integrity. To investigate in vivo biological function of SUMO paralogs, we inactivated them in the early development of zebrafish. While zebrafish embryos deficient for all three SUMO paralogs, as Ubc9-deficient ones, displayed severe defects, loss of individual SUMO paralog was compatible with a normal development. SUMO-deficient embryos can be rescued by a single human or zebrafish SUMO. While key structural basic lysine residues and N-terminal unstructured stretch of SUMO are critical for in vivo rescue, the consensus Kll sumoylation site of SUMO2 is dispensable, implying that chain formation on this potential site is unessential for normal development. Inactivation of all three SUMOs triggered p53- dependent apoptosis and further inactivation of p53 restored normal zebrafish development. Interestingly, we also demonstrate that the dominant negative truncated form of p53, Δ113p53, significantly blunts SUMO depletion-induced p53 activity in vivo. Taken together, our results suggest that SUMO paralogs are indispensable, but redundant, in the early development of zebrafish.

邓小平故居的一副楹联

邓小平故居在四川省广安县协兴乡,是过去农村常见的一座普通的四合院,四周修竹、绿树滴翠。粉碎“四人帮”后,广安县有关部门曾数次提出要将其修整完善,都被小平同志认真地劝阻了。因此,这里至今仍然是解放初期的老样子。近些年来常有中外各地的群众,怀着崇敬的心情。

Effect of nerve growth factor on changes of myelin basic protein and functional repair of peripheral nerve following sciatic nerve injury in rats

Objective: To investigate the therapeutic effect of nerve growth factor (NGF) on changes of myelin basic protein (MBP) and functional repair of sensory and motor nerve following sciatic nerve injury. Methods: The sciatic nerves of rats were injured by sectioning with shaver,and divided into 3 groups: NGF group (Group A), group of normal saline solution (Group B), untreated group (Group C). The time point of observation was at the 4th week after operation. Sensory evoked potential (SEP) and motor evoked potential (MEP) were detected by Model WD 4000 nerve potential working diagnosis system. Immunohistochemical analysis was used for identification of MBP.Results: The latency of SEP in the Group A at the 4th week after operation was shorter than that in the Group B (P< 0.05 ). The MEP was elicited in 76% of the Group A and was higher than that in the Group B. Results of immunohistochemistry showed that there were less MBP positive cells in the Group A than in the Group B in one and four weeks respectively.Conclusions: NGF can improve the conductive function of injured peripheral nerve and facilitate regeneration of nerve.

Solitons on a Periodic Wave Background of the Modified KdV-Sine-Gordon Equation

The Backlund transformation（BT） of the m Kd V-s G equation is constructed by introducing a new transformation. Infinitely many nonlocal symmetries are obtained in terms of its BT. The soliton-periodic wave interaction solutions are explicitly derived by the classical Lie-group reduction method. Particularly, some special concrete soliton and periodic wave interaction solutions and their behaviours are discussed both in analytical and graphical ways.

Biomechanical effect of major extremity vessels in choosing repair methods for peripheral artery injury

Objective： To investigate the biomechanical effect of major extremity vessels to choose appropriate repair methods for vascular injuries of the extremities. Methods ： The data of 385 patients （337 males and 48 females, aged 18-71 years, mean = 32.6 years ） including 403 injured vessels, who suffered from vascular injuries of the extremities and were treated in our hospital from October 1960 to August 2005, were studied retrospectively in this article. We compared the results of different repair methods for the defect of vessels and evaluated different injured vessels for repairing arterial injuries with anastomosis and venous graft, respectively. Results： A significant difference was found between the defect lengths of the arteries repaired with anastomosis and venous graft （ P 〈 0. 0001 ）. The upper limits of the confidence interval in the defect lengths of the brachial artery, the femoral artery and the popliteal artery were 3.43 cm, 2. 38 cm and 2. 42 cm, respectively, when repaired with anastomosis. The lower limits were 2.16 cm, 2.16 cm and 1. 63 cm, respectively, when repaired with venous graft. The defect length of each artery repaired with venous graft had linear correlation with the graft length. Conclusion - Because of the longitudinal biomechanical difference of different options of repair arterial injuries. human peripheral vessels, are necessary for different arterial injuries.

CHK2 kinase in the DNA damage response and beyond

The serine/threonine kinase CHK2 is a keycomponent of the DNA damage response. In human cells, following genotoxic stress, CHK2 is activated and phosphorylates 〉20 proteins to induce the appropriate cellular response, which, depending on the extent of damage, the cell type, and other factors, could be cell cycle checkpoint activation, induction of apoptosis or senescence, DNA repair, or tolerance of the damage. Recently, CHK2 has also been found to have cellular functions independent of the presence of nuclear DNA lesions. In par- ticular, CHK2 participates in several molecular processes involved in DNA structure modification and cell cycle progression. In this review, we discuss the activity of CHK2 in response to DNA damage and in the maintenance of the biological functions in unstressed cells. These activities are also considered in relation to a possible role of CHK2 in tumorigenesis and, as a consequence, as a target of cancer therapy.

Clinical application of axonal repair technique for treatment of peripheral nerve injury

Objective: To evaluate the efficacy of axonal repair technique for treatment of peripheral nerve injury clinically. Methods: In 1998, the authors applied axonal repair technique to treat peripheral nerve injuries in 12 patients with 13 nerves. It consists of four steps, ie, stumps of the nerve being soaked in a modified Collins fluid, freezed, trimmed, and coapted with glue, making the injured nerve repaired at the axonal level. Results: The patients were followed up for an average of 13 months. Results showed that in 4 cases of first-stage contralateral C7 transfer, regenerating axons reached to the sternoclavicular joint or axilla at 4 to 7 months, offering the timing for performing the second-stage contralateral C7 transfer. In 5 cases of accessory nerve transferred to the suprascapular nerve, the abduction of the shoulder was 40° on average. In the other 3 patients with four different nerves repaired, results were also satisfactory. Conclusions: This technique is promising in the treatment of peripheral nerve injury.

Bridging peripheral nerve defect with chitosan-collagen film

Objective: To seek new method for the treatment of peripheral nerve injury. Methods: In rat model with sciatic nerve defect, chitosan collagen film was sutured into conduit to bridge 5 mm , 10 mm nerve defects. Rats that underwent end to end anastomosis were taken as controls. General observation, electrophysiological study, histological study and image analysis were performed at 4, 8, 12 weeks postoperatively. Results: In 5 mm nerve defects, the quality of nerve regeneration was similar to that of the control group. For 10 mm nerve defect, nerve regeneration was inferior to that of the control group. Chitosan collagen film obviously degraded at 12 weeks postoperatively. Conclusions: Chitosan collagen film conduit can be used to bridge peripheral nerve defect.

Small RNAs:Emerging key players in DNA double-strand break repair

DNA double-strand break （DSB） is the most deleterious form of DNA damage and poses great threat to genome stability. Eu- karyotes have evolved complex mechanisms to repair DSBs through coordinated actions of protein sensors, transducers, and effectors. DSB-induced small RNAs （diRNAs） or Dicer/Drosha-dependent RNAs （DDRNAs） have been recently discovered in plants and vertebrates, adding an unsuspected RNA component into the DSB repair pathway. DiRNAs/DDRNAs control DNA damage response （DDR） activation by affecting DDR loci formation and cell cycle checkpoint enforcement and are required for efficient DSB repair. Here, we summarize the findings of diRNAs/DDRNAs and discuss the possible mechanisms through which they act to facilitate DSB repair.

Global attractivity of positive periodic solution for a predator-prey model with modified Leslie-Gower Holling-type II schemes and a deviating argument

In this paper, by utilizing the comparison theorem and constructing a suitable Lyapunov functional the predator prey model with modified Leslie-Gower Holling-type II schemes and a deviating argument is studied. Some sufficient conditions are obtained for uniform persistence and global attraztivity of positive periodic solutions for this model. Furthermore, an example shows that the obtained criteria are easily verifiable.