[en] To study the focal cerebral ischemia/reperfusion (I/R) injury induced by a middle cerebral artery occlusion (MCAO), and the effects of Yulangsan (YLS) polysaccharide on this injury. This study took place in the Pharmacology Research Laboratory at Guangxi Medical University, China, between March and May 2007. Two hundred and forty rats were randomly divided into I/R group, sham-operated group, high-, medium-, and low-dose of YLS polysaccharide groups, and nimodipine (Nim) group. The animals were intragastrically administered with drugs for 7 days. An operation was performed to induce an MCAO model in the rats. Reperfusion was started after 2 hours of MCAO. The influences of YLS polysaccharide on the neurological score, the brain water content, the infarct volume, the activities of super oxide dismutase (SOD) and nitric oxide synthase (NOS), the contents of malondialdehyde (MDA) and nitric oxide (NO), the expressions of B-cell lymphoma/leukemia-2 (Bcl-2) and Bcl-2-associated X protein (Bax) in brain tissue were investigated; the morphological changes of rat cerebral cortical neurons were observed. Compared with the I/R group, YLS polysaccharide reduced the neurological score, the brain water content, the infract volume, MDA and NO contents, the NOS activity, and the expression of Bax, and increased SOD activity, and the expression of Bcl-2 in the brain tissue, and neuronal edema was reduced. The YLS polysaccharide has a protective effect on cerebral ischemia/ reperfusion injury; the mechanism may be related to attenuating free radicals, and increasing the Bcl-2/Bax ratio. (author)

[en] Objective: To discuss the difference in curative effect between ultrasound-guided microwave ablation (MWA) and surgical resection in treating early alveolar hepatic echinococcosis. Methods: The clinical data of a total of 40 patients with early alveolar hepatic echinococcosis, who were admitted to authors' hospital during the period from June 2015 to June 2017 to receive treatment, were retrospectively analyzed. According to the treatment method, the patients were divided into MWA group (n = 20) and surgery group (n = 20). The serum levels of total bilirubin (TBIL), alanine transaminase (ALT), aspartate transaminase (AST), platelet count (PLT), white blood cell (WBC) count, hemoglobin (HGB) and albumin (ALB), the postoperative complications, and the recurrence of disease were compared between the two groups. Results: No statistically significant differences in preoperative serum levels of AST, ALT, TBIL, WBC, HGB, ALB and PLT existed between the two groups (P > 0.05). The differences in postoperative serum levels of TBIL and PLT between the two groups were not statistically significant (P > 0.05). The postoperative serum levels of ALT, AST and WBC in MWA group were remarkably lower than those in surgery group (P < 0.05), while the postoperative serum levels of HGB and ALB in MWA group were strikingly higher than those in surgery group (P < 0.05). In MWA group, no postoperative infection, renal failure, liver failure, biliary leakage, or bleeding occurred, and postoperative follow-up imaging examination indicated that the lesions were stable and no signs of recurrence were observed. In surgery group, one patient developed postoperative infection, no renal failure, liver failure, biliary leakage, bleeding, or recurrence occurred. Statistically significant differences in postoperative hospitalization days and total medical expenses existed between the two groups (P < 0.05). Conclusion: For the treatment of early alveolar hepatic echinococcosis, MWA can achieve satisfactory results. MWA is superior to surgical resection in rapid postoperative recovery, short hospitalization period and low medical expenses. (authors)

[en] The design method of pressure vessel consists of the elastic analysis method and the elastic-plastic analysis method. The design method based on elastic-plastic theory with more complex computation process contributes to lightweight design, and avoids uncertainty of stress classification in the complex structures. Tubesheet is the main part of high pressure heater, which is very thick based on Chinese code GB151 for the design of heat exchangers. Increased tubesheet with large thermal stress are not conducive to manufacture, heat transmission and detection. The application of limit load method and elastic-plastic method in the analysis and design of high pressure heater tube is to provide direction for the lightweight research of tubesheet. It is shown that high stress appears on the inner wall of jointing of tubesheet with the head due to the original tubesheet owning enough rigidity related to thickness, which should be noted in the design. The limit load method and elastoplastic method could be assessed in the plastic collapse assessment after optimizing the thickness of the tube plate by 5% on the basis of the existing rule design. Compared with the limit load method, the elastic-plastic method could obtain higher limit load due to its higher computational precision. On the other hand, the design method of elastic-plastic analysis method is not required to consider the determination of limit load per ASME VIII-2 judged by its convergence. The elastic-plastic analysis method is worth further study, which is helpful to the revision and improvement of relevant standards in China. (paper)

[en] A process for the recovery of high-purity metallic cobalt from NMC-type Li-ion battery, which uses lithium nickel manganese cobalt oxide as the cathode material, is reported in this manuscript. First, leaching experiments of the cathode material were done with different types of acid and base solutions to compare the leaching efficiency of cobalt and the other metals. Complete leaching of cobalt is required for the recovering process and was eventually achieved when using a reductive leaching method. Second, extraction experiments were done by using different extractants to extract different metals from the leachate solution. It was found that a consecutive and selective separation of manganese first and cobalt second could result in the highest yield and selectivity of cobalt. P-204 (di(2-ethylhexyl)phosphoric acid) was used for extracting manganese, and P-507 (2-ethyl(hexyl)phosphonic acid mono-2-ethylhexyl ester) was used for extracting cobalt. Last, electrowinning was applied using the cobalt solution after back-extraction to recover cobalt into its metallic form. The overall recovery ratio for cobalt was calculated to be about 93% with a high purity of 98.8%.

[en] A novel Li4Ti5O12 (LTO) composite with nitrogen doped multi-walled carbon nanotubes (CNTs), denoted N-C-LTO, was successfully prepared via simple thermal annealing of CNTs in the presence of melamine. For comparison, LTO, C-LTO (Li4Ti5O12/CNT) were also synthesized. N-C-LTO demonstrated the best electrochemical performance among the samples. Even at a high charge/discharge rate of 20 C, the reversible capacity was maintained at the high level of 100 mAhg-1. Moreover, after 150 cycles at 3.0 C, 90.7 % of the capacity was retained with negligible capacity fading. The excellent electrochemical performance was possibly due to the nitrogen in the doped CNTs, which maintained the benefits of the nitrogen as good electron donating. (paper)

[en] Recently, the single metal wire (SW) has become attractive for its potential applications in the terahertz and higher frequency range. However, as the most simple and typical surface plasmon polariton (SPP) transmission line, its study seems far from enough. Many important transmission behaviours have not been explained satisfactorily from the viewpoint of physics. In this paper, making use of the modified Drude model (MDM) based on the Sommerfeld theory, the transmission behaviours of SPPs along SW are systemically investigated theoretically. Some important physical phenomena such as the mode transformation, the lifetime of the radiative mode and the resonance frequency are revealed, and their mechanisms are explored. The results obtained in the paper will facilitate a general understanding of the features and the physical essence of the SPP transmission, not only for SW itself but also for other SPP transmission lines

No abstract available

[en] Surface plasmon polaritons excited by an electron beam can be transformed into coherent and tunable light radiation waves with power enhancement in the simple structure of a metal film with a dielectric medium loading. In this paper, the process of the radiation transformation of this radiation, and the dependencies of the radiation characteristics on the parameters of the structure and the electron beam are studied in detail. The radiation power enhancement is greatly influenced by the beam energy and the film thickness in the infrared to ultraviolet frequency region. Up to 122 times radiation power enhancement and 6.5% radiation frequency tuning band can be obtained by optimizing the beam energy and the parameters of the film. (paper)

[en] In this paper, the enhanced terahertz radiation transformed from surface plasmon polaritons, excited by a uniformly moving electron bunch, in a structure consisting of a monolayer graphene supported on a dielectric grating with arbitrary profile is investigated. The results show that the grating profile has significant influence on the dispersion curves and radiation characteristics including radiation frequency and intensity. The dependence of dispersion and radiation characteristics on the grating shape for both the symmetric and asymmetric gratings is studied in detail. Moreover, we find that, for an asymmetric grating with certain profile, there exist two different diffraction types, and one of the two types can provide higher radiation intensity comparing to the other one. These results will definitely facilitate the practical application in developing a room-temperature, tunable, coherent and miniature terahertz radiation source. (paper)

[en] The possibility of an electron beam exciting surface plasmons in conducting metal is discussed in this paper. A planar perfect-structure with subwavelength holes is proposed. The phenomenon that mimicking surface plasmon waves can be excited and amplified by an electron beam is proved theoretically and numerically. The mechanism of transmission through a subwavelength hole array is exploited to enhance the interaction between the electron beam and the mimicking surface plasmons