Influence of the Use of a Collagen Membrane Placed on the Bone Window after Sinus Floor Augmentation—An Experimental Study in Rabbits

Background: We studied the influence on healing of a resorbable membrane covering the osteotomy site after maxillary sinus grafting, evaluated in different regions of the augmented area. Methods: Maxillary sinus augmentation was performed in 24 New Zealand rabbits. Osteotomy, 4 × 6 mm, were performed bilaterally. A collagenated cortico-cancellous porcine bone was used to fill the elevated region. A collagen membrane was randomly placed over the osteotomy site on one side (MG), and the other side was left uncovered (NMG). The animals were euthanized after 2, 4, and 8 weeks; and histomorphometric analysis was performed in eight different regions. Results: New bone percentages were similar in both groups. There were no statistically significant differences. In MG, the overall percentages were 15.6 ± 7.3%, 22.9 ± 6.1%, and 24.9 ± 12.0% after 2, 4, and 8 weeks, respectively. In NMG, the percentages were 11.2 ± 4.5%, 24.1 ± 5.7%, and 24.5 ± 15.7%, respectively. The proportions of new bone in the various regions after 8 weeks were 31 ± 8.9% and 29.9 ± 9.1% in the bone walls region, 25 ± 10.1% and 32.8 ± 9.1% in the submucosa region, 22.6 ± 21.6% and 10.9 ± 11.5 in the middle region, 17.3 ± 14% and 13.4 ± 9.8% in the close-to-window region, and 21.8 ± 11.6%, 19.1 ± 6.4% in the osteotomy region—for MG and NMG, respectively. Conclusions: In both groups the greatest amounts of bone formation occurred near to the pre-existing bone walls, followed by the sub-mucosa region. The smallest amounts were found in the close-to-window region, followed by the central region. The placement of a collagen membrane to cover the osteotomy site did not influence the amount of new bone formation after sinus grafting.

Sub-waveform optimization for producing water window single-order harmonic

Through the sub-waveform optimization of the laser field, a potential method to produce the water window single-order harmonic (SOH) has been proposed. First, by properly introducing the chirps of two-color field, the SOHs from 303th order to 616th order can be obtained. Theoretical analyses show that the folding region on the harmonic emission process, caused by the multiple accelerations, is responsible for the enhanced SOH. Moreover, the folding region is dependent on the neighbor two half-cycle profiles. Thus, through further controlling the sub-waveform of the folding region by using the unipolar pulse, the folding region on the harmonic emission process will be extended to the higher photon energy region, including the water window region. Finally, by properly choosing the combinations of chirps and unipolar pulses, the water window SOH from 446th order to 833th order (from 345 eV to 645 eV) can be obtained.

Oligomerization of phenothiazin-5-ium tetraiodide in the presence of bases

Methylene blue and its structural analogs (phenothiazine derivatives) are well known photodynamically and photochemically active agents, which are used in modern medicine, biology, and industry due to their low toxicity, high absorption in the therapeutic window region (600-660 nm). Methylene blue being one of the most studied phenothiazine derivative is employed as an antibacterial agent and also as an antidote to cyanide, carbon monoxide and hydrogen sulfide. Phenothiazin-5-ium tetraiodide is one of the most convenient precursors for the synthesis of structural analogues of methylene blue among the variety of modern synthetic approaches. Nucleophilic addition of aromatic and aliphatic amines to phenothiazin-5-ium tetraiodide can be used to obtain a wide range of 3,7-phenothiazine-5-ium derivatives. The specificities of addition reactions of dialkylamines and aromatic amines to phenothiazin-5-ium tetraiodide are low yields and formation of difficultly separable mixtures of products. It was found that reactions of phenathiazin-5-ium tetraiodide with amines containing secondary and tertiary amino groups lead to oligomerization of phenathiazin-5-ium tetraiodide (3,10-positions). Basicity of tertiary amino group is crucial in oligomerization of phenathiazin-5-ium tetraiodide. It is shown, that triethylamine use as a base allows to synthesize of oligo(3,10)phenothiazines with high yields. According to 1Н, 13C NMR, IR spectroscopy data and MALDI mass-spectrometry data, thereaction product is a mixture of oligomers, consisting mainly of three to four units.

Endoscopic visualisation of the round window during cochlear implantation

BackgroundEndoscopes provide a magnified view of the middle ear and visualisation of hidden areas. Otoendoscopes facilitate excellent visualisation of the round window niche during cochlear implantation.ObjectiveTo compare microscopic and endoscopic visualisation of the round window membrane during cochlear implantation in 20 patients.MethodsTwenty patients who underwent cochlear implantation were included in the study. After maximum exposure of the round window, the accessibility of the round window membrane was graded according to the St Thomas Hospital classification, first by microscope and then by endoscope.ResultsWith the use of the endoscope, visualisation of the round window membrane improved in all the patients as compared to the microscope. The electrode array was inserted via a round window or extended round window approach in all but two cases; the latter cases required bony cochleostomy because of unfavourable anatomy.ConclusionThe main benefit of endoscope-assisted cochlear implantation is improved visibility of the round window region.

Control of the polarization direction of isolated attosecond pulses using inhomogeneous two-color fields

We theoretically demonstrate the control of the polarization direction of isolated attosecond pulses (IAPs) with inhomogeneous two-color fields synthesized by an 800-nm fundamental pulse and a 2000-nm control pulse having crossed linear polarizations. The results show that by using the temporally and spatially shaped field, the high-order harmonic generation (HHG) process can be efficiently controlled. An ultra-broad supercontinuum ranging from 150th to 400th harmonics which covers the water window region is generated. Such a supercontinuum supports the generation of a 64-as linearly polarized IAP, whose polarization direction is at about 45° with respect to the x axis. Moreover, we analyze the influence of the inhomogeneity parameters and the relative angle of the fundamental and control pulses on the IAP generation. It is shown that the polarization direction of the IAP can rotate in a wide range approximately from 8° to 90° relative to the x axis when the inhomogeneity parameters and the relative angle vary.

Improvement of High-Order Harmonic Generation Via Controlling Multiple Acceleration–Recombination Process

The multiple acceleration–recombination process in high-order harmonic generation (HHG) has been investigated and discussed. Generally, the HHG can be explained through the ionization–acceleration–recombination process in each half-cycle waveform of the laser field. In this article, through the waveform control via the two-colour frequency-chirping laser field, the multiple acceleration–recombination process of the free electron in a specific “W” waveform structure can be found, which will lead to the larger emitted photon energies. Moreover, with the optimization of this “W” waveform by changing the frequency chirps, the carrier envelope phases, and the delay time, not only the efficiency of HHG can be enhanced compared with that from the original chirp-free pulse, but also the larger harmonic cutoff can be obtained. Further, with the assistance of the unipolar pulses, the cutoff and the efficiency of HHG can be further improved, showing a water window spectral continuum with the intensity enhancement of 66 times. As a result, by properly superposing some selected harmonics on the spectral continuum, three intense 38-as pulses in the water window region can be obtained.

Optimization of the high-speed train head using the radial basis function morphing method

Aerodynamic drag reduction is one of the most important issues in the development of high-speed trains. This study focused on the aerodynamic optimization of the train by modifying the shape of the head car and tail car. Three shape parameters were studied in this paper: the angle of cab-window, nose-length, and nose-width of the train. The effects of shape parameters on the aerodynamic drag coefficients of the head car and tail car were discussed, respectively. It can be concluded that the flat surface of the window region, long and sharp nose are the distinguishing characters of a high-speed train with low resistance. Response surface models of the shape parameters and the aerodynamic drag of the head car and tail car were obtained, respectively. Based on these models, an aerodynamic optimization was performed to achieve the optimal shape. As a result, the total aerodynamic drag of the optimal train decreased by 2.05% compared with the original value.

Generation of water window single attosecond pulse from multi-cycle mid-infrared laser field with chirp gating modulation

A potential scheme to produce the water window single attosecond pulses (SAPs) from the multi-cycle mid-infrared (MIR) laser field has been investigated with the help of the chirp gating modulation. It is found that with the introduction of the laser chirp (i.e. up-chirp or down-chirp modulation), the extension of the harmonic cutoff can be achieved and the single harmonic radiation peak (HRP) can be selected during the harmonic emission process. Moreover, the chirp gating modulation on the high-order harmonic generation (HHG) is sensitive to the few-cycle pulse duration, but it is not very sensitive to the multi-cycle pulse duration. Moreover, a larger extension of the harmonic cutoff covering the whole water window region can be found with the help of the multi-cycle down-chirp modulation. Further, by properly choosing the coherent superposition of the ground state and the high Rydberg state as the initial state, the efficiency of HHG can be enhanced by 5 orders of magnitude. Finally, a series of high-intensity sub-40as pulses covering the water window region can be obtained.