Search results for "Plates"

Buckling and Postbuckling of Stiffened Composite Panels with Cracks and Delaminations by Ritz Approach

2017

A Ritz approach for the analysis of buckling and post-buckling of stiffened composite panels with through-the-thickness cracks and/or delaminations is presented. The structure is modeled as the assembly of plate elements whose behavior is described by the First-order Shear Deformation Theory and von Karman’s geometric nonlinearities. Penalty techniques ensure continuity along the edges of contiguous plate elements and the enforcement of the restraints on the external boundaries. They are also used to avoid interpenetration problems. General symmetric and unsymmetric stacking sequences are considered. A computer code has been developed and used to validate the proposed method, comparing the …

Dynamic Behaviour of an Axially Moving Plate Undergoing Small Cylindrical Deformation Submerged in Axially Flowing Ideal Fluid

2011

Abstract The out-of-plane dynamic response of a moving plate, travelling between two rollers at a constant velocity, is studied, taking into account the mutual interaction between the vibrating plate and the surrounding, axially flowing ideal fluid. Transverse displacement of the plate (assumed cylindrical) is described by an integro-differential equation that includes a local inertia term, Coriolis and centrifugal forces, the aerodynamic reaction of the external medium, the vertical projection of membrane tension, the bending resistance, and external perturbation forces. In the two-dimensional model thus set up, the aerodynamic reaction is found analytically as a functional of the cylindri…

Twin axial vortices generated by Fibonacci lenses.

2013

Optical vortex beams, generated by Diffractive Optical Elements (DOEs), are capable of creating optical traps and other multifunctional micromanipulators for very specific tasks in the microscopic scale. Using the Fibonacci sequence, we have discovered a new family of DOEs that inherently behave as bifocal vortex lenses, and where the ratio of the two focal distances approaches the golden mean. The disctintive optical properties of these Fibonacci vortex lenses are experimentally demonstrated. We believe that the versatility and potential scalability of these lenses may allow for new applications in micro and nanophotonics.

Efficacy of Zero-Profile Device versus Plate and Cage Implant for Treatment of Symptomatic Adjacent Segment Disease After Anterior Cervical Diskectom…

2018

Aromatic N-oxide templates open inclusion and dimeric capsular assemblies with methylresorcinarene

2015

C2-2-methylresorcinarene forms host–guest complexes with pyridine N-oxide and quinoline N-oxide. In solution the NMR studies support the 1 : 1 host–guest complexes while in the solid state, the single crystal X-ray diffraction studies reveal dimeric capsule-like assemblies with 2 : 3 and 2 : 2 host–guest stoichiometry.

A new method for the mapping of 5' ends of RNAs.

2008

In this article, we describe a new procedure to map 5' ends of RNAs. The procedure consists in the use of specific RNase H digestion of a hybrid formed by the RNA and a complementary DNA oligonucleotide. Northern blot hybridization of the resulting RNA fragment allows an accurate measurement of its length. Although we generally use this procedure as a control of previously performed primer extension analyses, the absence of nonspecific bands, which often occur in primer extensions on RNA templates with extended secondary structures, suggests that our method may be preferable when these difficult templates are analyzed.

Translation of hepatitis B virus (HBV) surface proteins from the HBV pregenome and precore RNAs in Semliki Forest virus-driven expression.

2004

Hepatitis B virus (HBV) pregenome RNA (pgRNA) serves as a translation template for the HBV core (HBc) protein and viral polymerase (Pol). HBV precore RNA (pcRNA) directs the synthesis of the precore (preC) protein, a precursor of the hepatitis B e antigen (HBeAg). pgRNA and pcRNA were expressed in the Semliki Forest virus (SFV) expression system. Besides the HBc and preC proteins, there was revealed the synthesis of all three forms of HBV surface (HBs) proteins: long (LHBs), middle (MHBs) and short (SHBs), the start codons of which are located more than 1000 nt downstream of the HBc and preC start codons. Moreover, other HBV templates, such as 3′-truncated pgRNA lacking 3′ direct repeat and…

Multiple-plane image formation by Walsh zone plates.

2018

[EN] A radial Walsh filter is a phase binary diffractive optical element characterized by a set of concentric rings that take the phase values 0 or ¿, corresponding to the values + 1 or ¿1 of a given radial Walsh function. Therefore, a Walsh filter can be re-interpreted as an aperiodic multifocal zone plate, capable to produce images of multiple planes simultaneously in a single output plane of an image forming system. In this paper, we experimentally demonstrate for the first time the focusing capabilities of these structures. Additionally, we report the first achievement of images of multiple-plane objects in a single image plane with these aperiodic diffractive lenses.

Locking Reconstruction Double Plating of Distal Humeral Fractures: How Many Screws in the Distal Ulnar Column Segment in A3 Fracture Provide Superior…

2009

Objectives: Two 90-degree configurations of locking reconstruction plates with different numbers of screws in the distal ulnar column segment of distal extra-articular humeral fractures with metaphyseal comminution (A3) were biomechanically investigated. Methods: Eight pairs of fresh-frozen human humeri were used. For paired comparison, the humeri were divided into 2 randomized groups. In both groups, double-plate osteosyntheses with locking reconstruction plates were performed in 90-degree configurations. In group 1, the posteriorly placed radial column plate exceeded the capitellum and the ulnar column plate extended into the ulnar sulcus. The ulnar plate was molded around the medial epic…

A method for rapid generation of competitive standard molecules for RT-PCR avoiding the problem of competitor/probe cross-reactions.

1995

The analysis of gene expression is a widespread issue in a growing number of fields such as molecular genetics, immunology, and medical diagnostics. The ideal method for mRNA detection should be fast, inexpensive, sensitive, and reliable. Well-elaborated standard methods such as Northern hybridization, Sl-mapping, and RNAse protection are useful and recommended, but only reverse transcription PCR (RT-PCR) gives the highest possible sensitivity required. For many issues it is necessary not only to detect a distinct mRNA but to compare changes in mRNA levels. The use of RT-PCR for such semiquantitative and quantitative approaches resolves problems attributable to the intrinsic property of PCR…