Retinal Displacement: Providing New Insights for Retinal Detachment Surgery

Purpose. To review the current literature on retinal displacement and provide a discussion of potential risk factors, postoperative outcomes, and future directions. Methods. Two databases, MEDLINE and EMBASE, were mined using a directed search strategy to identify all articles on retinal displacement. Results. We identified 1522 articles. A total of n = 14 articles were retained. We provide an overview on the potential influence of surgical type (n = 4), tamponade agents (n = 5), postoperative posture (n = 6), and preoperative retinal status (n = 5) on incidence of retinal displacement and visual outcomes (n = 8). Discussion. Pars plana vitrectomy (PPV) with gas tamponade is associated with displacement rates of up to 72%, typically in a downward direction. Meanwhile, pneumatic retinopexy and PPV with silicone oil may offer similar surgical success with a significantly lower risk of displacement. The impact of heavy liquids such as perfluorocarbon liquid, postoperative positioning and preoperative extent of detachment on displacement remains inconclusive. Patients with displacement had a significantly lower visual acuity and higher rates of distortion than those without displacement. However, not all patients with displacement experienced visual symptoms. Conclusion. Retinal displacement is a new concept in our understanding of retinal detachment. Additional studies are needed to better define its impact on postsurgical outcomes.

The yield values of densimetric fractions from typical chernozems of different land use types

One of the most justified and applied approaches to isolating pools of soil organic matter is fractionation in heavy liquids. The main problem with this approach is rather large losses in the separation of fractions at the stage of washing fractions from heavy liquids. The paper presents a densimetric fractionation protocol that can significantly reduce these losses. It is suggested to use 0.001 M HCl for washing. This approach, in comparison with distilled water, allows reducing losses of weight from 15 to 5% and of carbon from 7.5 to 2.5%. The paper provides a detailed protocol, used by the Laboratory of Soil Biochemistry of V.V. Dokuchaev Soil Science Institute, to isolate four densimetric fractions using sodium polytungstate solutions: free and occluded SOM with a density of <1.6 g/cm3, occluded SOM – of 1.6–2.0 g/cm3, and a mineral residue with a density >2.0 g/cm3. In the work we used samples of typical chernozems of different land use types. It was shown that the processes of soil restoration and degradation significantly affect the content of light occluded soil organic matter.

Effect of heat on Organic and Inorganic components in some Non-coking Lower Gondwana Coals

The concentration of different maceral groups and minerals in coal influence the quality as each of them behaves differently during heat treatment. The purpose of this study is to know how the maceral groups and minerals are behaving at different temperature conditions. Therefore, various maceral groups and minerals were concentrated by using heavy liquids of different specific gravities (1.3, 1.7 and 1.9). The generated density fractions were treated with heat at 400, 600, 800 and 1000°C. All the density fractions at various temperature conditions along with feed sample were investigated by Optical Microscopy, X-ray Diffractometry (XRD), Electron-probe Micro Analysis (EPMA) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The results from these analyses suggest that fusinite and sclerotinite are the most stable macerals, whereas quartz is the most stable mineral during pyrolysis. Telocollinite found to be oxidized very prominently at 400 °C . Siderite and pyrite thermally altered to form hematite above 400°C and 800 °C respectively. Kaolinite converted to metakaolin followed by mullite with increasing temperature.

Mineralogy of Duné s Sand of Missan Dune Fields Southeastern Iraq

The aim of this study is to define the mineralogical composition of Missan dune fields South Eastern of Iraq, and try to determine the origin or the source of these dunes . Three main types of dunes were recognized in the studied area, these are: barchanoid ridge, barchans and nabkha dunes. The direction of these dunes is northwest to southeast. The dunes in Missan dune fields were divided into three fields according to the vari- eties in the composition and geographical position in the studied area, these three fields are: Al-Manziliyah, Middle Chailat, and Said Subair dune fields. 9 samples were collected from these fields, the samples were separated into light and heavy fraction by heavy liquids. The light fraction composed from quartz, feldspar, and rock fragments, the rock fragments composed mainly of carbonate, chert, igneous, and metamorphic rock fragments . The heavy minerals are mostly opaques, chlorite, pyroxenes, amphiboles, epidotes, zircon, garnet, muscovite, biotite, kyanite, staurolite, and rutile . The percentages of heavy minerals fraction to light minerals fraction was very vari- able in which the percentage of heavy minerals in Sayid Subair field are higher than the percentage in Al-Manziliyah field.The source area of these sediments is the recent sed- iment that deposited in the flood plain and traces of the Tigris river and the outcrops of upper Miocene-Pliocene rocks in the eastern of studied area (Himreen Anticline and Zagros Mountain).

DETERMINATION OF LATERAL PRESSURE OF LIGHT CONCRETE MIX LAID IN THE FORMWORK ACCORDING WITH EXISTING TECHNIQUES AND INSTALLATION PROCESS MODELING FROM THE POSITION OF OPERATIONAL IMPACTS

The analysis of existing Russian and foreign methods for determination of lateral pressure of light concrete mix laid in the formwork, its scope and technological factors is proposed as well as the study of the processes associated with the laying of light concrete mixture in the formwork system from the position of the resulting operational impacts. The results reveal that the pressure on the formwork for these methods depends on speed of concreting of the structure, and the distribution of lateral pressure light concrete mixture according to the height of the formwork is similar to the eff ects of heavy concrete and may be made by analogy with the plots of hydrostatic pressure, it is necessary to bring the properties of light concrete mix that consolidate by vibration to the properties of the heavy liquids with the corresponding density values.

Evaluation of Arabian Super Light Crude Oil for Use in a F-Class DLN Combustion System

Global trends in natural gas and distillate oil prices and availability continue to influence decisions on power generation fuel choice. In some regions, heavy liquids are being selected as gas turbine fuels. One particular crude oil, Arabian Super Light (ASL), has the potential to be used as a primary or back-up fuel in F-class heavy duty gas turbines. This paper presents the results of a set of tests performed on ASL to determine the potential of using it in a Dry Low NOx (DLN) combustion system for operation in an F-class gas turbine.