Role of quark-interchange processes in evolution of mesonic matter

We divide the cross section for a meson-meson reaction into three parts. The first part is for the quark-interchange process, the second for quark-antiquark annihilation processes and the third for resonant processes. Master rate equations are established to yield time dependence of fugacities of pions, rhos, kaons and vetor kaons. The equations include cross sections for inelastic scattering of pions, rhos, kaons and vector kaons. Cross sections for quark-interchange-induced reactions, that were obtained in a potential model, are parametrized for convenient use. The number densities of pion and rho (kaon and vector kaon) are altered by quark-interchange processes in equal magnitudes but opposite signs. The master rate equations combined with the hydrodynamic equations for longitudinal and transverse expansion are solved with many sets of initial meson fugacities. Quark-interchange processes are shown to be important in the contribution of the inelastic meson-meson scattering to evolution of mesonic matter.Comment: 28 pages, 1 figure, 8 table

2-Trifluoro­methyl-1H-benzimidazol-3-ium perchlorate

In the title salt, C8H6F3N2 +·ClO4 −, the atoms of the benzimidazole ring (including H atoms) are nearly coplanar (r.m.s. deviation of the fitted atoms = 0.0122 Å) and the triflouromethyl group lies out of this plane. The perchlorate anion adopts a distorted tetra­hedral conformation with the Cl—O bond distances ranging from 1.412 (3) to 1.439 (2) Å. The benzimidazolium cations are linked to adjacent anions by inter­molecular N—H⋯O hydrogen bonds, forming chains

Synthesis and biological activities of O6-alkylguanine derivatives

The synthesis of some biologically active O6-alkylguanine derivatives was achieved by alkoxylation of 2-amino-6-chloropurine with sodium alkoxides in polar aprotic solvent (DMSO) conditions. The starting material 2-amino-6-chloropurine was prepared by chlorination of 2,9-diacetylguanine (obtained from acetylation of commercially available guanine) by PEG-2000 phase transfer catalysis. The structures of the products were deduced from elemental analysis and spectral data (IR, 1H NMR, and mass spectra). All the title compounds were screened for their antifungal activities, and some of the compounds showed promising activities. KEY WORDS: O6-Alkylguanine derivatives, 2-Amino-6-chloropurine, Synthesis, Fungicidal activity  Bull. Chem. Soc. Ethiop. 2010, 24(3), 425-432

Discovery of the transient magnetar 3XMM J185246.6+003317 near supernova remnant Kesteven 79 with XMM-Newton

We report the serendipitous discovery with XMM-Newton that 3XMM J185246.6+003317 is an 11.56 s X-ray pulsar located 1' away from the southern boundary of supernova remnant Kes 79. The spin-down rate of 3XMM J185246.6+003317 is $<1.1\times 10^{-13}$ s s$^{-1}$, which, together with the long period P=11.558714(2) s, indicates a dipolar surface magnetic field of $1.7$ Myr, and a spin-down luminosity of $<2.8\times 10^{30}$ erg s$^{-1}$. The X-ray spectrum of the source is best-fitted with a resonant Compton scattering model, and can be also adequately described by a blackbody model. The observations covering a seven month span from 2008 to 2009 show variations in the spectral properties of the source, with the luminosity decreasing from $2.7\times 10^{34}$ erg s$^{-1}$ to $4.6 \times 10^{33}$ erg s$^{-1}$, along with a decrease of the blackbody temperature from $kT\approx 0.8$ keV to $\approx0.6$ keV. The X-ray luminosity of the source is higher than its spin-down luminosity, ruling out rotation as a power source. The combined timing and spectral properties, the non-detection of any optical or infrared counterpart, together with the lack of detection of the source in archival X-ray data prior to the 2008 XMM-Newton observation, point to this source being a newly discovered transient low-B magnetar undergoing an outburst decay during the XMM-Newton observations. The non-detection by Chandra in 2001 sets an upper limit $4\times 10^{32}$ erg s$^{-1}$ to the quiescent luminosity of 3XMM J185246.6+003317. Its period is the longest among currently known transient magnetars. The foreground absorption toward 3XMM J185246.6+003317 is similar to that of Kes 79, suggesting a similar distance of $\sim$7.1 kpc.Comment: 7 pages, 4 figures, 1 table; updated to match the published versio

人造血管在血液透析造瘘的应用及护理

Objective: To study the application of artificial blood vessels to build alternative standard arteriovenous fistula blood vessels for hemodialysis maintenance nursing. Methods: 17 cases of patients underwent artificial blood vessel transplantation, material for ptfe (PTEE), 30 cm in length, inner diameter 5mm, from 2012 to 2013 in Jinan military region general hospital. Artificial blood vessel transplantation is more operated on brachial vein, cephalic vein, median cubital vein and basilic vein. When the anastomosis among artificial blood vessels and brachial artery and vein anastomosis was established, the arterial end was on the inner side. When the anastomosis among brachial vein, median cubital vein and basilic vein was established, the arterial end was on the outside for the extension of vascular access. Results: 15 cases have hemodialysis after two months’ treatment, 1 case have artificial blood vessel fistula after swelling for 4 months, infection of thrombosis occurred one month after the operation in 1 case. Conclusion: Artificial blood vessel show good biocompatibility, high long-term patency rate, blood flow, and convenient puncture point. It builds the “lifeline” for the patients who are unable to establish a good vascular access. It is of great significance to improve the management of artificial blood vessel fistula for maintenance hemodialysis patients.目的  研究应用人造血管造瘘替代标准动静脉血管维持血液透析的护理。方法  本院自2012—2013年对17例血液透析患者进行人造血管移植术，材料为聚四氟乙烯（PTEE）材料，长度30cm，内径5mm。人造血管移植术多选择与肱动脉和头静脉或肘正中静脉、贵要静脉U型吻合。人造血管与肱动脉和头静脉吻合时，动脉端在内侧。但肱动脉与肘正中静脉、贵要静脉吻合时，为延长有效性血管通路，动脉端则在外侧。结果  15例术后2个月成熟顺利实施血液透析，1例持续肿胀4个月后开始应用，1例术后1个月出现感染血栓形成。结论  人造血管具有生物相容性好、长期通畅率高、血流量大、穿刺方便、穿刺部位充足等优点，为自身血管条件差、无法建立良好血管通路的透析患者提供了可靠的血管通路，为维持性血液透析患者建立了“生命线”。加强透析过程中的人造血管内瘘管理对于维持透析患者良好的血管通路具有重要意义

Page Curve and Phase Transition in deformed Jackiw-Teitelboim Gravity

We consider the entanglement island in a deformed Jackiw-Teitelboim black hole in the presence of the phase transition. This black hole has the van der Waals-Maxwell-like phase structure as it is coupled with a Maxwell field. We study the behavior of the Page curve of this black hole by using the island paradigm. In the fixed charge ensemble, we discuss different situations with different charges that influence the system's phase structure. There is only a Hawking-Page phase transition in the absence of charges, which leads to an unstable small black hole. Hence, the related Page curve does not exist. However, a van der Waals-Maxwell-like phase transition occurs in the presence of charges. This yields three black hole solutions. The Page curve of the middle size black hole does not exist. For the extremal black hole, the Page time approaches zero in the phase transition situation but becomes divergent without the phase transition. In a word, we study the Page curve and the island paradigm for different black hole phases and in different phase transition situations.Comment: 28 pages, 13 figures, references added, published versio

Injury assessment via stress analysis of the human knee joint

The largest articulation inside human body is the knee joint which is composed by hard components, soft tissues and surrounded muscles. The knee is a mobile hinge, and it permits flexion, extension, slight internal and external rotation of the leg. The knee joint is vulnerable to both sharp injury and chronic osteoarthritis. Once have been injured, the knee joint is not easily restored. This study employs separately the experimental measurement, reverse engineering and finite element analysis to investigate the dynamic characteristics of intricate knee joint. The three-dimensional geometric model of each component of knee joint includes hard tissues and soft tissues. The hard tissues have femur, tibia, fibula, patella and the soft tissues have meniscus, patellar ligament, medial and lateral collateral ligament, a pair of cruciate ligaments, etc. Then the model is imported into ANSYS software. Via modal, periodic excitation and impact analysis, the dynamic characteristics of each component and the whole knee model are received. The fundamental mode shapes, natural frequencies and stresses of all the components of knee are also obtained. These normal modes are essential when investigating the dynamic motion of the whole knee. The results show that after impact, the soft tissues have larger displacement than that of the hard tissues. Consequently, the fracture occurs when the stretch which is caused by external force excess ultimate strength of the component. It also explains why the athletes frequently injure the ligaments and tendons of the knee or ankle during the intensive exercise. Therefore, by reducing the motion of articulation, the professional player could not only reduce the generated internal stresses in the tissue but also consequently lessen the chance of injury