An anatomical study in a Chinese population of the position of the rib head for placing anterior vertebral body screws

The instrumentation of anterior vertebral body screws has become an important approach for the treatment of unstable fractures or curvature of the spine, but little attention has been paid to the starting point of placing the screws and the variability of the rib head position. We analysed the variability of rib head position in a Chinese population in terms of the spinal canal and vertebral body using computed tomography (CT). Images from transverse CT scans of the T4–T12 vertebral bodies of 30 normal individuals were 3-D reconstructed and analysed for measurement of parameters which included: 1) distance between the left (or right) anterior border of the rib head and the posterior (or anterior) margin of the vertebral body [L(R)ARHP(A)VB]; 2) left (or right) transverse dimension [L(R)TD]; 3) left (or right) posterior (or anterior) safe angle [L(R)P(A)SA]; and 4) distance between the inferior border of the left (or right) rib head and the superior (or inferior) end-plate in the sagittal plane [I L(R)RHS(I)EP]. The ARHPVB, PSA, and IRHIEP gradually decrease, but ARHAVB, TD, ASA, and IRHSEP gradually increase, from T4 to T12, indicating that the position of the rib head changes from a more anterior position to a more posterior position and from a more superior position to a more inferior position, as the number of the vertebra increases. Our study has provided a comprehensive reference guide for accurate and safe instrumentation of vertebral body screws in treating related spine diseases. (Folia Morphol 2010; 69, 4: 232-240

Large Bi-2212 single crystal growth by the floating-zone technique

Effects of the growth velocity on the crystal growth behavior of Bi_2Sr_2Ca_1Cu_2O_x (Bi-2212) have been studied by floating zone technique. The results show that a necessary condition for obtaining large single crystals along the c-axis is that the solid-liquid interface of a growing rod maintains a stable planar growth front. The planar liquid-solid growth interface tends to break down into a cellular interface, while the growth velocity is higher than 0.25 mm/h. Single crystals of up to 50x7.2x7 mm3 along the a-, b- and caxes have been cut in a 7.2 mm diameter rod with optimum growth conditions. Tconset is 91 K measured by magnetic properties measurement system (MPMS) for as-grown crystals. Optical polarization microscope and neutron diffraction show that the quality of the single crystals is good.Comment: 5 pages, 4 figure

Acoustic phonon transport through a double-bend quantum waveguide

In this work, using the scattering matrix method, we have investigated the transmission coefficients and the thermal conductivity in a double-bend waveguide structure. The transmission coefficients show strong resonances due to the scattering in the midsection of a double-bend structure; the positions and the widths of the resonance peaks are determined by the dimensions of the midsection of the structure. And the scattering in the double-bend structure makes the thermal conductivity decreases with the increasing of the temperature first, then increases after reaches a minimum. Furthermore, the investigations of the multiple double-bend structures indicate that the first additional double-bend structure suppresses the transmission coefficient and the frequency gap formed; and the additional double-bend structures determine the numbers of the resonance peaks at the frequency just above the gap region. These results could be useful for the design of phonon devices.Comment: 13 pages, 6 figures, elsart.cls is use

From double Lie groupoids to local Lie 2-groupoids

We apply the bar construction to the nerve of a double Lie groupoid to obtain a local Lie 2-groupoid. As an application, we recover Haefliger's fundamental groupoid from the fundamental double groupoid of a Lie groupoid. In the case of a symplectic double groupoid, we study the induced closed 2-form on the associated local Lie 2-groupoid, which leads us to propose a definition of a symplectic 2-groupoid.Comment: 23 pages, a few minor changes, including a correction to Lemma 6.

Effect of a Liner Material on the Formation of the Wrapping ExplosivelyFormed Penetrator

The wrapping explosively-formed penetrator is a new approach to shape change based on a pre-folded double liner: outer liner of higher density forming the shell and the inner liner of lower density forming the core. The penetrator can not only penetrate the armor but can form lots of fragments behind the target when it attacks light armored objects. The fragments generated by the lateral enhanced effect are able to destroy crew and equipment improving the integrated damage outcome. The shape and materials of the core and shell are the main factors controlling the penetrability and formation of fragments. The effect of liner materials on penetration was studied. with AUTODYN analysis. The results show that the difference in the through-thickness velocities and the interface of the two liners are the main factors leading to the separation of the core and shell. Penetrator with an evident lateral enhanced effect could be helpful to choose appropriate liner materials. The feasibility of forming the penetrator with double liners is substantiated providing a reference for the selection of liner material.Витой взрывной пенетратор – новая конструкция, основаная на использовании предварительно свернутого двойного слоя материала: наружный слой высокой плотности, формирующий облицовку, и внутренний слой низкой плотности, образующий сердцевину. Пенетратор не только проникает сквозь броню, но и обладает высоким бризантным дробящим действием за мишенью при атаке объектов с легкой броней. Осколки, образовавшиеся вследствие значительного латерального эффекта, способны уничтожать живую силу и боевую технику, увеличивая тем самым нанесенный ущерб. Конструкция и материалы сердцевины и облицовки являются основными факторами, определяющими проницаемость заряда и формирование осколков. Влияние материала слоев на структуру пенетратора изучено с помощью анализа AUTODYN. Различие в скорости по толщине и на поверхности контакта двух слоев обеспечивает отделение сердцевины от облицовки. Пенетратор, обладающий значительным латеральным эффектом, может быть использован в процедуре выбора материалов слоев. Подтверждена эффективность конструкции пенетратора с использованием двойных слоев

Poisson sigma model on the sphere

We evaluate the path integral of the Poisson sigma model on sphere and study the correlators of quantum observables. We argue that for the path integral to be well-defined the corresponding Poisson structure should be unimodular. The construction of the finite dimensional BV theory is presented and we argue that it is responsible for the leading semiclassical contribution. For a (twisted) generalized Kahler manifold we discuss the gauge fixed action for the Poisson sigma model. Using the localization we prove that for the holomorphic Poisson structure the semiclassical result for the correlators is indeed the full quantum result.Comment: 38 page

Novel D-hordein-like HMW glutenin sequences isolated from Psathyrostachys juncea by thermal asymmetric interlaced PCR

New high-molecular-weight glutenin (HMW glutenin) sequences isolated from six Psathyrostachys juncea accessions by thermal asymmetric interlaced PCR differ from previous sequences from this species. They showed novel modifications in all of the structural domains, with unique C-terminal residues, and their N-terminal lengths were the longest among the HMW glutenins reported to date. In their repetitive domains, there were three repeatable motif units: 13-residue [GYWH(/I/Y)YT(/Q)S(/T)VTSPQQ], hexapeptide (PGQGQQ), and tetrapeptide (ITVS). The 13-residue repeats were restricted to the current sequences, while the tetrapeptides were only shared by D-hordein and the current sequences. However, these sequences were not expressed as normal HMW glutenin proteins because an in-frame stop codon located in the C-termini interrupted the intact open reading frames. A phylogenetic analysis supported different origins of the P. juncea HMW glutenin sequences than that revealed by a previous study. The current sequences showed a close relationship with D-hordein but appeared to be more primitive

Di-hadron azimuthal correlation and Mach-like cone structure in parton/hadron transport model

In the framework of a multi-phase transport model (AMPT) with both partonic and hadronic interactions, azimuthal correlations between trigger particles and associated scattering particles have been studied by the mixing-event technique. The momentum ranges of these particles are $3< p^{trig}_T< 6$ GeV/$c$ and $0.15< p_{T}^{assoc} < 3$ GeV/$c$ (soft), or $2.5<p^{trig}_T<$ 4 GeV/$c$ and $1< p_{T}^{assoc} < 2.5$ GeV/$c$ (hard) in Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. A Mach-like structure has been observed in correlation functions for central collisions. By comparing scenarios with and without parton cascade and hadronic rescattering, we show that both partonic and hadronic dynamical mechanisms contribute to the Mach-like structure of the associated particle azimuthal correlations. The contribution of hadronic dynamical process can not be ignored in the emergence of Mach-like correlations of the soft scattered associated hadrons. However, hadronic rescattering alone cannot reproduce experimental amplitude of Mach-like cone on away-side, and the parton cascade process is essential to describe experimental amplitude of Mach-like cone on away-side. In addition, both the associated multiplicity and the sum of $p_{T}$ decrease, whileas the $$ increases, with the impact parameter in the AMPT model including partonic dynamics from string melting scenario.Comment: 9 pages, 5 figures; Physics Letters B 641, 362-367 (2006

Characterization of a novel 4.0-kb y-type HMW-GS from Eremopyrum distans

A novel 4.0-kb Fy was sequenced and bacterially expressed. This gene, the largest y-type HMW-GS currently reported, is 4,032-bp long and encodes a mature protein with 1,321 amino acid (AA) residues. The 4.0-kb Fy shows novel modifications in all domains. In the N-terminal, it contains only 67 AA residues, as three short peptides are absent. In the repetitive domain, the undecapeptide RYYPSVTSPQQ is completely lost and the dodecapeptide GSYYPGQTSPQQ is partially absent. A novel motif unit, PGQQ, is present in addition to the two standard motif units PGQGQQ and GYYPTSPQQ. Besides, an extra cysteine residue also occurs in the middle of this domain. The large molecular mass of the 4.0-kb Fy is mainly due to the presence of an extra-long repetitive domain with 1,279 AA residues. The novel 4.0-kb Fy gene is of interest in HMW-GS gene evolution as well as to wheat quality improvement with regard to its longest repetitive domain length and extra cysteines residues

Charmless Bs→PP,PV,VVB_s\to PP, PV, VV Decays Based on the six-quark Effective Hamiltonian with Strong Phase Effects II

We provide a systematic study of charmless $B_s \to PP, PV, VV$ decays ($P$ and $V$ denote pseudoscalar and vector mesons, respectively) based on an approximate six-quark operator effective Hamiltonian from QCD. The calculation of the relevant hard-scattering kernels is carried out, the resulting transition form factors are consistent with the results of QCD sum rule calculations. By taking into account important classes of power corrections involving "chirally-enhanced" terms and the vertex corrections as well as weak annihilation contributions with non-trivial strong phase, we present predictions for the branching ratios and CP asymmetries of $B_s$ decays into PP, PV and VV final states, and also for the corresponding polarization observables in VV final states. It is found that the weak annihilation contributions with non-trivial strong phase have remarkable effects on the observables in the color-suppressed and penguin-dominated decay modes. In addition, we discuss the SU(3) flavor symmetry and show that the symmetry relations are generally respected