A clinical study on salvage hepatectomy for treating recurrent liver cancer after radiofrequency ablation

Objective We studied the efficacy of salvage hepatectomy for treating recurrent hepatic cancer after radiofrequency ablation(RFA). Methods A retrospective analysis of 67 patients who had recurrent liver cancer after RFA treatment and received salvage hepatectomy in the Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University(China), from January 2006 to January 2014, was performed. The analysis included patient gender, age, hepatitis type, alpha-fetoprotein(AFP), and TNM stage prior to RFA and salvage hepatectomy, overall survival rates, and tumor-free survival rates after salvage hepatectomy. Results Among the 67 patients, there were 57 cases of hepatitis B, two cases of hepatitis C, and eight cases did not have hepatitis. AFP levels in patients ranged from 3 to 4521 ng/m L(median 33 ng/m L). Before RFA, 54 cases were stage I tumors, and 13 were stage II tumors. Tumor sizes varied from 0.82 to 4.83 cm(median 3.0 cm). In 20 cases, one RFA was performed, and for 47 cases, RFA was repeated. RFAablated region diameters ranged from 3.8 to 5.2 cm(median 4.5 cm). The interval between the salvage surgical resection and RFA was 3–37 months. Before salvage hepatectomy, 23 stage I tumors, 12 stage II tumors, and 32 stage III tumors were present(size ranged 4.83–11.84 cm; median 6.3 cm). For salvage hepatectomy, laparotomy was performed for 56 cases, and laparoscopy was performed for 28 cases. Inflow clamping was performed for 39 cases(15–45 min). Surgery was 219–370 min and intraoperative blood loss was 100–2100 m L. For 13 cases, intraoperative blood transfusion was required. Tumor pathological data revealed 31, 35, and 1 poorly, moderately, and well differentiated tumors, respectively. No patients died due to operative complications, and hospital stays were 8–10 days. Overall and tumor-free survival rates were 85% and 79% for 1 year, 50% and 20% for 3 years, and 39% and 19% for 5 years, respectively. KaplanMeier analysis and Cox regression confirmed that tumor number and size prior to salvage liver cancer were risk factors affecting survival. Conclusion Patients who received RFA to treat early-stage liver cancer with postoperative recurrent stage I tumors have satisfactory outcomes with salvage hepatectomy.

Microstructural Dependence of Friction and Wear Behavior in Biological Shells

As an essential renewable mineral resource,mollusk shells can be used as handicrafts,building materials,adsor-bents,etc.However,there are few reports on the wear resistance of their structures.The Vicker’s hardness and friction,and wear resistance of different microstructures in mollusk shells were comparatively studied in the pre-sent work.The hardness of prismatic structures is lower than that of cross-lamellar and nacreous structures.How-ever,the experimental results of sliding tests indicate that the prismatic structure exhibits the best anti-wear ability compared with foliated,crossed-lamellar,and nacreous structures.The anti-wear and hardness do not present a positive correlation,as the wear resistance properties of different microstructures in mollusk shells are governed jointly by organic matrix,structural arrangement,and basic building block actions.The present researchfindings are expected to provide fundamental insight into the design of renewable bionic materials with high wear resistance.

The Analytical Expressions for Computing the Minimum Distance between a Point and a Torus

In this paper, we present the analytical expressions for computing the minimum distance between a point and a torus, which is called the orthogonal projection point problem. If the test point is on the outside of the torus and the test point is at the center axis of the torus, we present that the orthogonal projection point set is a circle perpendicular to the center axis of the torus;if not, the analytical expression for the orthogonal projection point problem is also given. Furthermore, if the test point is in the inside of the torus, we also give the corresponding analytical expression for orthogonal projection point for two cases.

Controlling Carbide Evolution to Improve the Ductility in High Specific Young’s Modulus Steels

A high specific Young’s modulus steel could be achieved by introducing a large fraction of kappa-carbides(κ-carbide),and its ductility was improved by efficiency divorced eutectoid transformation(DET)treatment.For this steel,carbon and aluminum contents affect not only the carbide fraction,but also the type and morphology of carbides,and consequently the mechanical properties.In this work,the alloy was designed by considering both the carbide morphology and Young’s modulus,and the carbides in the high specific Young’s modulus steels were adjusted by controlling carbon content in a suitable range for achieving a good combination of strength and ductility.The detailed microstructure evolution process during DET reaction was studied,and it was found that a higher austenitizing temperature and the cooling rate lower than 300℃ h^(−1) are suitable.The blocky carbides could be avoided by designing the carbon content in a limited content range.The microstructure-property relationship of the experimental steels was also discussed for giving an impetus to the future development of high specific Young’s modulus steels.

超细PtCu纳米线的表面结构调控及其增强的醇类电催化氧化作用

铂基纳米催化剂的表面结构调控是提升其电催化性能和实现多功能性的有效途径.本工作报道了两种超细PtCu纳米线(光滑型和粗糙型)的湿化学合成方法及其电催化醇氧化的性能.研究结果表明,粗糙型PtCu合金表面具有丰富的原子台阶,对多种电化学反应具有较好的催化活性.密度泛函理论模拟表明,粗糙型PtCu纳米线具有较好的反应活性,这是由于Pt-Cu位点之间的协同作用促进了反应过程中水的解离和羧基中间体的脱氢.本工作为能源相关电催化体系中合金纳米催化剂的合理设计提供了思路.

Optimization of Grain Boundary Character Distribution in Fe-18Cr-18Mn-0.63N High-Nitrogen Austenitic Stainless Steel

Grain boundary engineering（GBE） is a practice of improving resistance to grain boundary failure of the material through increasing the proportion of low Σ coincidence site lattice（CSL） grain boundaries（special grain boundaries） in the grain boundary character distribution（GBCD）. The GBCD in a cold rolled and annealed Fe-18Cr-18Mn-0.63N high-nitrogen austenitic stainless steel was analyzed by electron back scatter difraction（EBSD）. The results show that the optimization process of GBE in the conventional austenitic stainless steel cannot be well applied to this high-nitrogen austenitic stainless steel. The percentage of low ΣCSL grain boundaries could increase from 47.3% for the solid solution treated high-nitrogen austenitic stainless steel specimen to 82.0% for the specimen after 5% cold rolling reduction and then annealing at 1423 K for 10 min.These special boundaries of high proportion efectively interrupt the connectivity of conventional high angle grain boundary network and thus achieve the GBCD optimization for the high-nitrogen austenitic stainless steel.

用于骨缺损修复的新型可注射自固化复合材料

硫酸钙骨水泥具有良好的骨传导性,但降解速率快、生物活性差的缺点限制了其临床应用.本文将β-磷酸三钙纳米颗粒(粒径43.8±9.0 nm)和半水硫酸钙颗粒(粒径5–21μm)混合作为固相,与液相聚乙烯醇溶液(5 wt.%)按优化重量比混匀,制备了可注射自固化复合材料.该材料具有合理的自固化时间(11.7–19.2 min)及适宜的压缩强度(2.28–6.33 MPa).同时,利用镁颗粒作为成孔剂,制备出大孔径(大于100μm)的多孔支架.体外细胞实验显示,MC3T3-E1细胞伸展良好,表现出大量的板状伪足和伸展的丝状伪足,表明该复合材料无细胞毒性.将可注射复合材料植入比格犬股骨髁缺损区,10个月后骨缺损愈合良好,表明该材料具有良好的骨缺损修复潜力.

Design, synthesis, and fungicidal activity of novel 1,3,4-oxadiazole derivatives

Employing the intermediate derivatization method（IDM）, twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified by1 H NMR,13 C NMR, MS and elemental analyses, compound 4 was further identified by single-crystal X-ray diffraction. Antifungal activities against rice sheath blight（RSB） and sorghum anthracnose（SA） were evaluated by the mycelium linear growth rate method. Compounds 4, 16 and 20 displayed significant activities against RSB（EC50= 0.88 mg/L, 0.91 mg/L and 0.85 mg/L, respectively）,higher than the reference tebuconazole; While compound 3 exhibited higher activity against SA（EC50= 1.03 mg/L）, equal to commercial pyraclostrobin（EC50= 1.06 mg/L）. The study showed that compound 20 is a promising fungicide for further development.

Structural changes of a bacteriophage upon DNA packaging and maturation

Dear Editor,Tailed,double-stranded DNA(dsDNA)bacteriophages,which belong to the order of Caudovirales,have a tail attached to a pentameric vertex of the icosahedral capsid shell(head)through a 12-fold portal(Johnson and Chiu,2007).The phages package genomic dsDNA into a round procapsid using the portal in complex with an ATP-dependent terminase complex as the motor.During packaging,the procapsid shell expands to a more angular intermediate to match the size of the viral genome(Guo et al.,2014).When the phage head is full,the portal detects internal pressure and conveys a signal from the inner capsid to the exterior,which triggers a sequence of events-the terminase complex cleaving mature DNA genome from a multi-genome concatemer,the release of the terminase complex from the portal,and the attachment of the tail complex-in the completion of phage assembly(Lander et al.,2006;Johnson and Chiu,2007).At the beginning of phage infection,the tail is responsible for receptor recognition,and the portal and tail act as a tunnel for DNA delivery into the host cytoplasm(Johnson and Chiu,2007).These mechanisms of DNA packaging and ejection may also be conserved in many other DNA viruses,including herpesvirus(Wang et al.,2020;Yang et al.,2020).

A Geometric Strategy Algorithm for Orthogonal Pro jection onto a Parametric Surface

In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot point) on the surface as well as its corresponding parameter, which is also called the point projection problem of a parametric surface. The geometric strategy algorithm (hereafter GSA) presented consists of two parts as follows. The normal curvature to a given parametric surface is used to find the corresponding foot point firstly, and then the Taylor's expansion of the parametric surface is employed to compute parameter increments and to get the iteration formula to calculate the orthogonal projection point of test point to the parametric surface. Our geometric strategy algorithm is essentially dependent on the geometric property of the normal curvature, and performs better than existing methods in two ways. Firstly, GSA converges faster than existing methods, such as the method to turn the problem into a root-finding of nonlinear system, subdividing methods, clipping methods, geometric methods (tangent vector and geometric curvature) and hybrid second-order method, etc. Specially, it converges faster than the classical Newton's iterative method. Secondly, GSA is independent of the initial iterative value, which we prove in Theorem 1. Many numerical examples confirm GSA's robustness and efficiency.

Growth Ring-dependent Fracture Toughness of Sea Urchin Spines Estimated by Boundary Effect Model

Although the fracture behavior of sea urchin spines has been extensively investigated,there is as yet a lack of quantitative estimation on the effect of growth rings on the fracture properties of sea urchin spines.In sea urchin spines,much denser pores present in growth rings rather than porous layers.The tensile strength and fracture toughness of sea urchin spine samples with different numbers of growth rings are measured by the Boundary Effect Model(BEM).The experimental results of single-edge notched three-point bending tests indicate that the BEM is an appropriate method to estimate the fracture toughness of the present porous sea urchin spines,and the number of growth rings plays an important role in the fracture properties of spines.Specifically,the tensile strength and fracture toughness of sea urchin spines can be significantly improved with the increase in the number of growth rings,and their fracture toughness can even reach a relatively high value compared with some other porous materials with an identical porosity.The present research findings are expected to provide a fundamental insight into the design of high-performance bionic materials with a highly porous structure.

Anisotropic Mechanical Response of Nacre to Heat Treatment Under Indentation:Effect of Structural Orientation

It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentation behavior on fresh and heat-treated nacres from two orthogonal directions,and the results demonstrate that both hardness value and damage tolerance can remain almost unchanged on the cross-section with the organic matrix degeneration,despite a significant deterioration on the platelet surface.Theoretical analyses suggest that the anisotropic response of indentation behavior to heat treatment in nacre is primarily caused by its structural orientation.Specifically,compared with a single layer of irregular interplatelet interfaces in cross-sectional specimens,the multiple layers of parallel interlamellar interfaces in in-plane specimens exhibit a much greater ability to impede indenter-triggered destruction,and heat treatments would reduce the in-plane hardness but nearly have no effect on the cross-sectional hardness.Moreover,the deeper embedding of platelets in cross-sectional specimens enhances their resistance to interface cracking caused by organic matrix degradation at high temperatures,leading to a reduced sensitivity to damage.Therefore,the indentation behavior of nacre shows different tendencies in response to variations in the organic matrix state along normal and parallel directions.