Gamma ray multiplicity of a^(240)Pu solid sphere simulated by JMCT

Determining the mass of plutonium metal is an important research objective in the field of nuclear material accounting and control.Based on the 3D neutron and photon transport code JMCT(Jointed Monte Carlo Transport),the gamma ray multiplicity of ^(240)Pu was simulated in this study,and the average number of gamma rays leaking from ^(240)Pu solid spheres with different masses was also obtained.The simulation results show that there is a oneto-one correspondence between the average number of gamma rays and the mass of ^(240)Pu solid spheres in the range of 0.50–3.00 kg.This result provides a basis for using the average number of gamma rays to account for the mass of ^(240)Pu.

Primary animal experiment to test the feasibility of a novel Y-Z magnetic hepatic portal blocking band

BACKGROUND Hepatic portal blood flow occlusion is a common technique for reducing hepatic hemorrhage during hepatectomy.We designed a novel Y-Z magnetic hepatic portal blocking band(Y-Z MHPBB)based on the principle of magnetic compression technique.AIM To introduce the Y-Z MHPBB device and verify the feasibility of this device for hepatic portal blood flow occlusion in dogs.METHODS Ten beagles were randomly divided into the experimental group and control group.The operation time,intraoperative blood loss,the number of portal blood flow occlusions,the total time spent on adjusting the blocking band,and the average time spent on adjusting the blocking band were recorded.The surgeons evaluated the feasibility and flexibility of the two portal occlusion devices.RESULTS Laparoscopic hepatectomy was successfully performed in both the experimental group and control group.There was no statistical difference between the two groups in the operation time,intraoperative blood loss,and the number of hepatic portal blood flow occlusions.With respect to the total time spent on adjusting the blocking band and the average time spent on adjusting the blocking band,the experimental group showed significantly better outcomes than the control group,with a statistical difference(P<0.05).The operators found that the Y-Z MHPBB was superior to the modified T-tube in terms of operational flexibility.CONCLUSION The Y-Z MHPBB seems to be an ingenious design,accurate blood flow occlusion effect,and good flexibility;and it can be used for hepatic portal blood flow occlusion during laparoscopic hepatectomy.

Mechanism of resveratrol on the promotion of induced pluripotent stem cells

OBJECTIVE： To investigate the effects of resveratrol （RV） in reprogramming mouse embryonic fibroblasts （MEFs） into induced pluripotent stem cells （iPSCs） and the related mechanism. METHODS： Primary MEFs were isolated from E13.5 embryos and used within three passages. Retroviruses expressing Sox2 and Oct4 were produced by transfecting GP2-293t cells with recombinant plasmids murine stern cell virus （MSCV）-Sox2 and MSCV-Oct4. Supernatants containing retroviruses were obtained after 48-hour transfection and MEFs were then infected. Different concentrations （0, 5, 10 and 20 IJmol/L） of RV were added to embryonic stem cell （ESC） medium to culture MEFs 48 h post-infection, iPSC clones emerged and were further cultured. Expression of pluripotent markers of iPSCs was identified by cell immunofluorescence and reverse transcription-polymerase chain reaction. Both cytotoxicity and cell proliferation were assayed by Western blot analysis after RV was added into ESC medium. The ultrastructure change of mitochondria was observed by electron microscopy. RESULTS： More than 2.9-fold and 1.3-fold increases in colony number were observed by treatment with RV at 5 and 10 pmol/L, respectively. The reprogramming efficiency was significantly decreased by treatment with 20 pmol/L RV. The proliferation effect on MEFs or MEFs infected by two factors Sox2/Oct4 （2 factors-MEFs, 2F-MEFs） was investigated after RV treatment. At 20 pmol/L RV, induced cell apoptosis and proliferation inhibition were more obvious than those of 5 and 10 IJmol/L treatments. Clones were selected from the 10 pmol/L RV-treated group and cultured. Green fluorescent protein expression from one typical clone was silenced one month later which expressed ESC-associated marker genes Gdf3, Nanog, Ecatl, Fgf4 and Foxd3. Electron transmission microscope showed obvious cavitations in mitochondria. The expression of hypoxia-inducible factor-la was up-regulated when 2F-MEFs were treated with RV compared to the control group. CONCLUSION： RV improved the efficiency of reprogramming 2F-MEFs into iPSCs at low and moderate concentrations （5 and 10 pmol/L）. The effect of 10 pmol/L RV on reprogramming was much greater than that of 5 pmol/L RV. However, high concentration of RV （20 pmol/L） led to more severe cavitations in mitochondria and caused cytotoxic effects. Taken together, these findinqs suqclest that RV mimics hypoxia in cells and promotes reprogramming at a low concentration.

Magnetic compression anastomosis for reconstruction of digestive tract after total gastrectomy in beagle model

BACKGROUND Magnetic compression anastomosis(MCA)is a simple procedure contributing to a reliable anastomosis.However,digestive-tract reconstruction after total gastrectomy using MCA has not yet been reported.AIM To investigate the feasibility of MCA for simultaneous esophagojejunostomy and jejunojejunostomy after total gastrectomy using beagle dogs.METHODS Sixteen beagles were randomly divided into an MCA group(study group,n=8)and a manual-suture anastomosis group(control group,n=8).Two different magnetic anastomosis devices were used in the study group for esophagojejunal and jejunojejunal anastomoses.Both devices included a pair of circular daughter and parent magnets each.The time of esophagojejunostomy and jejunojejunostomy,postoperative complications,and survival rate of the two groups were compared.The dogs were sacrificed one month after the operation and their anastomotic specimens were obtained.Healing was observed by the naked eye and a light microscope.RESULTS Digestive-tract reconstruction after total gastrectomy was successfully completed in both groups(survival rate=100%).In the study group,esophagojejunal and jejunojejunal anastomoses took 6.13±0.58 and 4.06±0.42 min,respectively,significantly lower than those in the control group(15.63±1.53 min,P<0.001 and 10.31±1.07 min,P<0.001,respectively).Complications such as bleeding,anastomotic leakage,and anastomotic stenosis were not observed.In the study group,the magnets did not interfere with each other.Discharge time of the jejunojejunal magnetic anastomosis device was 10.75±1.28 d,while that of the esophagojejunal magnetic anastomosis device was 12.25±1.49 d.Residual silk was found in the control group.The study group showed a greater smoothness of the anastomosis than that of the control group.All layers of anastomosis healed well in both groups.CONCLUSION MCA is a safe and feasible procedure for digestive-tract reconstruction after total gastrectomy in this animal model.

A new sequential two-stent strategy for treating true distal left main trifurcation lesion

The incidence of significant left main(LM)coronary artery stenosis identified by coronary angiography was 5%−17.5%in various clinical presentations;about 80%of stenosis involved the LM bifurcation(LMB).[1]Although per-cutaneous coronary intervention(PCI)is an appro-priate alternative to coronary artery bypass graft in LM disease with low-to-intermediate anatomical complexity,[2]PCI for LMB lesions remains the most technically challenging for interventional cardiolo-gists with higher rates of acute periprocedural com-plications and higher risk of long-term major ad-verse cardiac events in the era of drug-eluting stent(DES).

Numerical Study on the Whole Process of Fireball Evolution in Strong Explosion

With the actual mean free path for radiation in air and a simplified nuclear device, a one-dimension simulation research on fireball phenomenon in a sea level atmosphere is carried out based on the multi-group radiation hydrodynamic codes(RDMG). It is shown that our theoretical calculations can describe the whole process of the fireball evolution for strong explosions from the early X-ray expansion stage to the shock wave propagation stage. The radius of the shock wave and the brightness of the fireball are in good agreement with the experimental results. The whole thermal radiation power curve of the fireball evolution for strong atmospheric explosion at sea level is plotted for the first time. The impact of radiation opacity of the nuclear device material on the early fireball phenomenon is also studied. It is found that trajectories of the radiation fronts and case shocks change with the opacity of equivalent device material.From our simulations, we find that only the early fireball depends on the details of the nuclear device, and after the formation of main shock, the evolution is determined by the properties of hot air for strong atmospheric explosion.

Investigation of the near-threshold cluster resonance in ^14C

An experiment for m p（14C},14C＊→10Be＋α）p inelastic excitation and decay was performed in inverse kinematics at a beam energy of 25.3 MeV/u. A series of 14C excited states, including a new one at 18.3（1） MeV, were observed which decay to various states of the final nucleus of 10Be. A specially designed telescope system, installed around zero degrees, played an essential role in detecting the resonant states near the α-separation threshold. A state at 14.1（1） MeV is clearly identified, being consistent with the predicted band-head of the molecular rotational band characterized by the π-bond linear chain configuration. Further clarification of the properties of this exotic state is suggested by using appropriate reaction tools.