Cognitive workload, complications and visual outcomes of phacoemulsification cataract surgery: Three-dimensional versus conventional microscope

Purpose To compare the surgical workload, complications, and visual outcomes using the three-dimensional visualization system with the conventional microscope in phacoemulsification cataract surgery. Design Prospective, non-randomized, open-label interventional study. Methods All patients underwent phacoemulsification cataract surgery using the three-dimensional visualization system or conventional microscope. Results Of the 203 eyes, 80 underwent surgery with the three-dimensional system while 123 underwent with the conventional microscope. No difference was noted in the total surgical duration, complication rates, and visual outcomes between the two groups. However, capsulorhexis was significantly faster using the conventional microscope while posterior chamber intraocular lens insertion was quicker using the three-dimensional system. In terms of cognitive workload comparison, no difference was seen in the surgeons’ heart rate, oxygen saturation levels, and surgery task load index total workload score and workload score for all six dimensions of the questionnaire, between the three-dimensional system and conventional microscope groups. As compared to baseline, the heart rate increased significantly during all surgical steps and at the end in both groups. When compared to baseline, the oxygen saturation levels were significantly raised during capsulorhexis, irrigation, and aspiration and posterior chamber intraocular lens insertion and at the end of the surgery in the three-dimensional group and during incision and at the end of the surgery in the conventional microscope group. Conclusions The duration of surgery, complications, and visual acuity outcomes remain unaffected while performing phacoemulsification cataract surgeries with the three-dimensional viewing system when compared to the conventional microscopes. Moreover, the surgeons’ cognitive workload too remains unaffected while utilizing this revolutionary three-dimensional surgical technology.

Solvability of a nonlinear three-dimensional system of difference equations with constant coefficients

In this paper, we show that the following three-dimensional system of difference equations x n + 1 = y n x n − 2 a x n − 2 + b z n − 1 , y n + 1 = z n y n − 2 c y n − 2 + d x n − 1 , z n + 1 = x n z n − 2 e z n − 2 + f y n − 1 , n ∈ N 0 , $$\begin{equation*} x_{n+1}=\frac{y_{n}x_{n-2}}{ax_{n-2}+bz_{n-1}}, \quad y_{n+1}=\frac{z_{n}y_{n-2}}{cy_{n-2}+dx_{n-1}}, \quad z_{n+1}=\frac{x_{n}z_{n-2}}{ez_{n-2}+fy_{n-1}}, \quad n\in \mathbb{N}_{0}, \end{equation*}$$ where the parameters a, b, c, d, e, f and the initial values x −i , y −i , z −i , i ∈ {0, 1, 2}, are complex numbers, can be solved, extending further some results in the literature. Also, we determine the forbidden set of the initial values by using the obtained formulas. Finally, an application concerning a three-dimensional system of difference equations are given.

Algorithm for determining the unbalances of continuous mixers rotors

The paper presents a design model of a continuous mixer, which employs working shafts with kneading and scraping blades as the equivalent rotors. The rotors are represented in the orthogonal system x, y, z. An algorithm for reducing a three-dimensional system to flat ones using three-dimensional simulation is proposed to simplify further calculations. The inertia and the mass moments of the rotors’ structural elements were determined for the specific parameters of the parts obtained by blanks casting taking into account the accuracy classes. The conducted research allowed developing recommendations for choosing rational methods for manufacturing parts of continuous mixers and optimal parameters for the operation of the mixer.

Vegetation of the Dniester Canyon and assessment of its adaptive potential

Syntaxonomy of the natural vegetation of the Dniester Canyon, including 20 classes, 30 orders, 44 alliances, and 71 associations, is presented. The natural vegetation of the canyon is formed by communities of the classes Carpino-Fagetea sylvaticae, Quercetea pubescentis, Quercetea robori-petraeae, Alno glutinosae-Populetea albae, Crataego-Prunetea, Festuco-Brometea, Trifolio-Geranietea sanguine, Molinio-Arrhenatheretea, Sedo-Scleranthetea, Phragmito-Magnocaricetea, Bolboschoenetea maritimi, and Isoëto-Nanojuncetea. Grassland vegetation is characterized by the highest syntaxonomic diversity. Quantitative assessment of syntaxonomic diversity in the three-dimensional system of ecological strategies of species according to Ramensky-Grime (CRS) was carried out. Adaptive capabilities, i.e. the potential for possible further development of forest, shrub and grassland habitats, have been assessed. It has been found that the dynamics of forest shrub, grass meadow and steppe communities is determined by successive endoecogenetic processes. In petrophytic communities, fluctuation changes are not manifested and successional changes are rather limited. Significant fluctuations are inherent in floodplain grasslands that depend on the sharp variability of moisture during the growing season. At the same time, it is emphasized that actual realization of these processes depends on influences of external drivers that can be considered as regulatory factors in possible development of syntaxa.

Four-vectors in relativity

“Four-vectors in relativity” gives a “soft” introduction to four-vectors by first setting up corresponding properties of three-vectors. These include the triangle rule for vector addition, and rotation of axes by a matrix multiplication. The physics of a three-dimensional system is unchanged by a rotation of the axes within which it is observed. Likewise the physics of a relativistic system is unchanged (“invariant”) under application of a Lorentz transformation.

A sensitivity interpolation algorithm for the concurrent optimization of bodies sharing a common design space

In this paper the problem of the concurrent topological optimization of two different bodies sharing a region of the design space is dealt with. This design problem focuses on the simultaneous optimization of two bodies (components) where not only the material distribution of each body has to be optimized but also the design space has to be divided among the two bodies. This novel optimization formulation represents a design problem in which more than one component have to be located inside a limited allowable room. Each component has its own function and load carrying requirements. In the paper a novel development solution algorithm is presented. With respect to previously published papers, the new algorithm comprises an interpolation of the density fields which allows a complete independence of the meshes of the two bodies. As the bodies can be meshed with any arbitrary mesh, this new algorithm can be applied to any real geometry. The developed algorithm is used to design a complex three dimensional system, namely a multi-component arm for a tube bending machine.