Are we mindful of nasal dorsal integrity during septal surgery? An imaging study of nasal keystone area

Objectives: Review of radiological images of the keystone area to assess risk of disruption to the nasal dorsum when separating the osseo-cartilaginous junction in septoplasty. Methods: A Cross sectional radiological study of adults who underwent CT scan of paranasal sinuses. Outcome measures included were: The Length of the keystone area (shorter length implies a higher risk of disruption) and a high-risk shape (high risk shape implies shorter keystone area) that can predispose to disruption of nasal dorsal integrity during septoplasty surgery. Certain nasal dimensions were evaluated to determine if they add risk to the dorsum. Results: CT scans of 343 patients were reviewed. The mean keystone area length was initially 10.42 mm that came down to 7.43 mm after adjustment in patients with high-risk shape. 31.5% of subjects were at risk of disruption to the dorsum due to short keystone area length <5 mm. Relatively shorter nasal bones (nasal bone length: overall dorsal length <0.49%) were associated with a shorter keystone area length (P = 0.004). Age, gender, septal deviation are not risk factors as they did not significantly influence keystone area length. Conclusions: One third of our patients (31.5%) had short KSA length < 5mm which carries higher risk of disruption to the dorsum integrity upon complete detachment of osseo-cartilaginous junction. We recommend preoperative CT imaging for thorough evaluation and precise measurement of KSA. Patients with relatively shorter nasal bones detected on examination (and confirmed radiologically), need to be recognized as they are more likely to have shorter KSA

Deep sclerectomy after DSAEK: A cautionary tale

A 78-year-old pseudophakic women with pseudoexfoliation glaucoma and 6-year history of prior Descemet’s stripping automated endothelial keratoplasty (DSAEK) underwent deep sclerectomy for a poorly controlled glaucoma. Exposure of the trabeculo-Descemet’s window (TDW), showed a very poor drainage. An attempt to dissect the fibrous tissue off the TDW resulted in perforation of the window needing peripheral iridectomy, followed by a white fibrous band which had to be excised to prevent blockade of the filtration channel. Postoperatively, there was complete detachment of the endothelial graft on day 1 with an intraocular pressure of 20 mm Hg. She was commenced on topical steroids and listed for a revisionary DSAEK in 6 weeks but when reviewed in a month postoperatively, a spontaneous reattachment of the endothelial graft was seen.

Cytopathic Effect of Vero Cells Adapted Bangladeshi Strain of Peste Des Petits Ruminants (PPR) Virus in Cell Culture

The present study described the cytopathic effect of PPR virus presently being used in serial passages at level of 60th in Vero cells and infected tissue culture fluid was used in this study as viral inoculum. Vero cells were grown on cover slip & were infected with tissue culture fluid at a fixed multiplicity of infection (MOI) 0.01. The infected cover slip along with control were stained with H&E stain at periodic intervals and cytopathic effect was studied with microscope. The cytopathic effect (CPE) was visible at first from 24 hpi and the Vero cells showed initial cell rounding, aggregation and syncytial development. Development of inclusion bodies and cell degradation was noticed by 72 hpi. Complete detachment of the cell monolayer was observed by 84 hpi. It is concluded that, development of numerous inclusion bodies is the indication of well adaptation & extensive multiplication of PPRV in Vero cells.

IMPACT OF DEFORMABLE STAMP WITH A MULTILAYERED WALL

In this paper, was performed by numerical work according to the difference scheme. Analysis of the numerical results showed: one of the important issues of contact interaction is to determine the duration of the impact of the colliding bodies. Obviously, under the condition of a hard clutch, sticking of the striker from the barrier will not occur. To study the process of complete breakage of mechanical contact (appearance of separation zones), we will use boundary conditions that simulate a perfectly smooth impact. Analysis of the dynamics of contact resistance has shown that its magnitude and features of evolution over time substantially depend on the geometric and physicomechanical parameters of the deformable system, as well as on the type of boundary conditions. An increase in the acoustic rigidity of the impactor leads to an increase in the amplitude and duration of the impact. The impact of a less rigid punch or the presence in the barrier of a shielding layer of a polymeric material reduces the contact resistance of the plate, but the force interaction between the impacted bodies is longer. As the analysis of the results shows, the evolution of contact stresses is characterized by a number of specific features. For example, there is a direct correlation between the height of the cylinder and the time of its complete detachment from the obstacle, which corresponds to the vanishing of the function   tk  . An increase in the acoustic rigidity of the impactor leads to a sharp increase in the amplitude of the total resistance and an increase in the duration of the contact interaction. Thus, the contours of the isolines provide a visual representation of the configuration of the areas at which points the stresses develop, immediately preceding the appearance of elastoplastic deformations for spall fractures (for brittle materials).

AGING OF SOMATIC CELLS AS AN EXAMPLE OF STRUCTURAL CHANGE IN THE VITREOUS BODY WITH AGE

Purpose:Based on the literature review and previous data, an analogy is drawn between the structure of the vitreous body and somatic cells. A comparison is made between changes in the vitreous body with age and the aging of somatic cells. Methods: A review of the literature and hypotheses. Results(Hypothesis): With age, the amount of hyaluronic acid and microfibrils decreases and the volume of “empty space” increases, leading to the collapse of the vitreous body and a complete detachment. Let us imagine the vitreous body as a giant cell with a central nucleus. The cytoskeleton permeates the entire cell. The cytoskeleton provides a structural framework for the cell, serving as a framework that determines cell shape and the general organization of the cytoplasm. Importantly, the cytoskeleton is much less rigid and permanent than its name implies. We see the same thing in the microfibrils of the vitreous body.Conclusion:With age, the density of the fibrillarstructure of the vitreous body decreases. This structure is apparently, is an evolutionary intracellular formation that formed as a result of the apoptosis of the mesenchymal cells that form the primary vitreous body. An analogy is drawn between the loss of the density of fibrils of the vitreous body and the density of the cytoskeleton of asomatic cell. The loss of the cytoskeleton of a cell is a fatal process that cannot be stopped. The cytoskeleton cannot hold the nucleus in the center of the cell, whichis why the nucleiof theoldercells are not in the center, but are shifted to the periphery.

On the structure and mass delivery towards circumplanetary discs

Circumplanetary discs (CPDs) that form around young gas giants are thought to be the sites of moon formation as well as an intermediate reservoir of gas that feeds the growth of the gas giant. How the physical properties of such CPDs are affected by the planetary mass and the overall opacity is relatively poorly understood. In order to clarify this, we used the global radiation hydrodynamics code FARGOCA with a grid structure that allows sufficient resolution of the planetary gravitational potential for a CPD to form. We then studied the gas flows and density–temperature structures that emerge as a function of planet mass, opacity, and potential depth. Our results indicate interesting structure formation for Jupiter-mass planets at low opacities, which we subsequently analysed in detail. Using an opacity level that is 100 times lower than that of the dust of the interstellar medium, our Jupiter-mass protoplanet features an envelope that is sufficiently cold for a CPD to form, and a free-fall region separating the CPD and the circumstellar disc that emerges. Interestingly, this free-fall region appears to be the result of supersonic erosion of outer envelope material, as opposed to the static structure formation that one would expect at low opacities. Our analysis reveals that the planetary spiral arms seem to pose a significant pressure barrier that needs to be overcome through radiative cooling in order for gas to be accreted onto the CPD. The circulation inside the CPD is near-Keplerian and is modified by the presence of CPD spiral arms. The same is true when we increase the planetary potential depth, which in turn increases the planetary luminosity, quenches the formation of a free-fall region, and decreases the rotation speed of the envelope by 10%. For high opacities, we recover results from the literature, finding an almost featureless hot envelope. With this work, we demonstrate the first simulation and analysis of a complete detachment process of a protoplanet from its parent disc in a 3D radiation hydrodynamics setting.

Zinc Phosphate and Resin Cements Provide Similar Bonding of Cast Metal Post to Dentin

Background: Cast metal posts-and-core are frequently used to retain restorations to extensively destroyed teeth. However, the influence of different cements on the posts bond strength to dentin remains unclear. Objective: to evaluate the effect of different cements on the bond strength of cast metal posts and dentin. Methods: Forty roots (14 mm length) of extracted human teeth were endodontically treated and prepared. Impressions of each root canal were taken to obtain customized cast metal posts. The roots were randomly divided into 4 groups (n=10): (1) ZP: zinc phosphate cement (non adhesive); (2) ARC_Sin: Single Bond adhesive and RelyX ARC; (3) ARC_Sco: Scotchbond adhesive and RelyX ARC; (4) U200: RelyX U200. After cementation, the samples were cross-sectioned to obtain specimens of 1mm thickness. Push-out test was performed applying a compressive load (0.5 mm/min) to the center of the metal post until failure. Bond strength was calculated based on the diameter of the root canal and the thickness of each specimen. Data were analyzed using ANOVA and Tukey (α=0.05). The fracture mode was analyzed. Results: Bond strength values were statistically similar between the groups (p>0.05). The fracture analysis showed the prevalence of mixed fractures (cement partially attached to the dentin and/or post). Experimental groups showed inexpressive amount of adhesive fractures (complete detachment of the cement from dentin and/or post). The ARC_Sco and U200 groups presented higher prevalence of dentin cohesive fracture. Conclusion: Bonding had no influence on the immediate bond strength between cast metal posts and root canal dentin.

DECM: A Discrete Element for Multiscale Modeling of Composite Materials Using the Cell Method

This paper presents a new numerical method for multiscale modeling of composite materials. The new numerical model, called DECM, consists of a DEM (Discrete Element Method) approach of the Cell Method (CM) and combines the main features of both the DEM and the CM. In particular, it offers the same degree of detail as the CM, on the microscale, and manages the discrete elements individually such as the DEM—allowing finite displacements and rotations—on the macroscale. Moreover, the DECM is able to activate crack propagation until complete detachment and automatically recognizes new contacts. Unlike other DEM approaches for modeling failure mechanisms in continuous media, the DECM does not require prior knowledge of the failure position. Furthermore, the DECM solves the problems in the space domain directly. Therefore, it does not require any dynamic relaxation techniques to obtain the static solution. For the sake of example, the paper shows the results offered by the DECM for axial and shear loading of a composite two-dimensional domain with periodic round inclusions. The paper also offers some insights into how the inclusions modify the stress field in composite continua.

DECM: A Discrete Element for Multiscale Modeling of Composite Materials Using the Cell Method

This paper presents a new numerical method for multiscale modeling of composite materials. The new numerical model, called DECM, consists in a DEM (Discrete Element Method) approach of the Cell Method (CM) and combines the main features of both the DEM and the CM. In particular, it offers the same degree of detail as the CM, on the microscale, and manages the discrete elements individually such as the DEM&mdash;allowing finite displacements and rotations&mdash;on the macroscale. Moreover, the DECM is able to activate crack propagation until complete detachment and automatically recognizes new contacts. Unlike other DEM approaches for modeling failure mechanisms in continuous media, the DECM does not require prior knowledge of the failure position. Furthermore, the DECM solves the problems in the space domain directly. Therefore, it does not require any dynamic relaxation techniques to obtain the static solution. For the sake of example, the paper shows the results offered by the DECM for axial and shear loading of a composite two-dimensional domain with periodic round inclusions. The paper also offers some insights into how the inclusions modify the stress field in composite continua.

DECM: A Discrete Element for Multiscale Modeling of Composite Materials Using the Cell Method

This paper presents a new numerical method for multiscale modeling of composite materials. The new numerical model, called DECM, consists in a DEM (Discrete Element Method) approach of the Cell Method (CM) and combines the main features of both the DEM and the CM. In particular, it offers the same degree of detail as the CM, on the microscale, and manages the discrete elements individually such as the DEM&mdash;allowing finite displacements and rotations&mdash;on the macroscale. Moreover, the DECM is able to activate crack propagation until complete detachment and automatically recognizes new contacts. Unlike other DEM approaches for modeling failure mechanisms in continuous media, the DECM does not require prior knowledge of the failure position. Furthermore, the DECM solves the problems in the space domain directly. Therefore, it does not require any dynamic relaxation techniques to obtain the static solution. For the sake of example, the paper shows the results offered by the DECM for axial and shear loading of a composite two-dimensional domain with periodic round inclusions. The paper also offers some insights into how the inclusions modify the stress field into composite continua.