Calculation of tunnel incision parameters during phacoemulsification in patients with previous anterior radial keratotomy

Background. The purpose was the choice of the type of tunnel incision on the basis of mathematical calculations in cataract patients with a previous anterior radial keratotomy. Materials and methods. During the calculations, the formula for the chord length of a circle was used: L = 2R · sin(α/2), where R is the radius of the cornea, α is the angle (in degrees) between the two corneal incisions. The chord length was measured on the limbus (upper edge of the tunnel incision) and 2 mm from the limbus (lower edge of the tunnel incision). The chord 2 mm from the limbus is more important because the distance between kerato­tomy incisions at this site is smaller. From 0.4 to 1.0 mm must be added to the width of the knife blade, depending on the type of postoperative corneal healing, which will be the key to crossing the incisions. Results. The most common knives are those 2.2 mm long with a tunnel length of 2 mm. Therefore, we perform calculations based on this knife in patients with 8 and 12 keratotomy incisions and a corneal diameter of 12 mm vertically and 11 mm horizontally. In patients with 8 keratotomy incisions, a 2.2 mm knife can be used for a corneal tunnel incision, and in patients with 16 incisions, it is impossible to use a corneal tunnel. Conclusions. In cataract patients who have previously undergone anterior radial keratotomy, a special approach is needed to the choice of tunnel incision. The choice of access depends on the diameter of the cornea, the number of keratotomy incisions and the width of the knife and is calculated using the formula for the chord length of a circle.

Study on working bodies of the soil preparation machine for sowing potatoes

The purpose of the study is to substantiate the parameters of the guide knife and the loosening pointed leg of the machine. The basic principles and methods of classical mechanics, mathematical analysis and statistics were used in this study. Theoretical studies were carried out to determine the parameters of the guide knife and the loosening pointed leg of the machine. It is established that to ensure the required value of the crest height with minimal energy consumption, the height and length of the guide knife should be 8 and 15 cm, respectively, the angle of the knife blade to the horizon - 30º, the longitudinal distance from the toe of the ploughshare body of the knife toe – 13 cm. To ensure the required crumbling of the soil, the width of the pointed loosening paw should be 15 cm.

ON THE ISSUE OF DETERMINING THE CRITICAL CUTTING SPEED OF THE MECHANISM FOR FORMING AND TRIMMING THE FALSE EDGE OF THE DORNIER RAPIER LOOM

In this paper, an attempt is made to develop a method for determining the critical cutting speed of the threads of the false edge of the edge-forming mechanism of the weaving rapier machine. The proposed calculation method takes into account the impact nature of the cutting process at a critical speed, which allows taking into account the mutual influence of the parameters of the working process and more fully assess the mechanics of this process, in which the intensity of the cutting force and the value of the contact stress take the maximum value. The paper calculates the critical cutting speed for some of the main types of threads used and the parameters of the knife blade. The presented calculation results can be used to select rational design parameters of the knife blade, depending on the type of processed threads, when designing and researching new edge-forming mechanisms on looms.

Retained Lumbar Intradiscal Surgical Knife Blade Retrieved Via Extended Extraforaminal Approach: Case Report and Review

Background and Importance: During a lumbar discectomy, the surgical knife might be broken and embedded deeply within the disc space. In some cases, it may be impossible to remove the broken blade during the initial surgery despite allocating several hours for this purpose. This fact may justify a subsequent surgical session. However, the eventual retrieval of the broken scalpel during a second surgical encounter can likewise be a very daunting challenge. Case Presantation: An L4-L5 discectomy in a young boy was complicated by the presence of an intradiscal broken surgical knife blade. The broken blade was successfully retrieved in a subsequent surgical session via the extended extraforaminal approach. Conclusion: The occurrence of an intradiscal retained broken scalpel has been rarely discussed within medical literature. There exist a wide variety of different approaches used for such a needed retrieval. The extended extraforaminal corridor has yet to be described within the context of medical journalism.

Life Course Practices in Bronze Age Landscapes of East Central Sweden: Beyond Divine Chiefs and Neodiffusionism

This paper treats the ritual traditions and practices connected with burials in Bronze Age cairns and stone-settings in the province of Södermanland in east central Sweden. The author discusses how the social and ritual roles of the individuals buried in cairns can be intertwined with the characteristics ofthe landscape contexts where caims have been placed. Particular attention is given to the meaning ofa special combination of artefacts —a razor, a pair of tweezers, a double-stud and a knife blade —found in Bronze Age burial contexts. The author suggests that the razor and the other ritual equipment may have been used in connection with life course rituals.

Broken surgical blade retrieval following lumbar discectomy through paravertebral/lateral transpsoas approach: A case report

Background: There are rare reports of broken surgical blades occurring during lumbar discectomy, and even fewer that discuss their retrieval. Case Description: While a 54-year-old male was undergoing a lumbar discectomy, the knife blade was broken. As it was difficult to retrieve the fragment through the original incision, the patient was closed, and a postoperative angio-computerized tomography (CT) was obtained. When the CT angiogram (CTA) documented the retained fragment had become lodged near the iliac vein within the psoas muscle, a second operation for blade retrieval, consisting of a paravertebral, lateral transpsoas approach, was successfully performed. Conclusion: In some cases, it is difficult to retrieve a broken scalpel blade during the index surgery. When this occurs, we would recommend closing the patient, and obtaining a CTA to better document the location of the retained foreign body. Based upon these findings, a safer second stage procedure may be performed (e.g., as in this case using a paravertebral lateral transpsoas approach) to avoid undue sequelae/morbidity.

Implementation of the new resource saving technology in manufacturing process

The authors of the article justify the expediency of applying resource saving in developing innovative technologies for hot rolling of boning knife blades from steel slabs. Such knives are widely used in meat processing industry. Metal consumption of the process was significantly reduced after changing the existing factory technology of making boning knives. The operation of cutting or grinding was replaced by hot rolling. The specific feature of the technology lies in minimizing the metal loss into shavings during the final processing of the steel slab by means of cutting. Reducing metal loss in making such steel parts and raising metal utilization rate are achieved by maximum possible approximation of forging configuration to the end product contour and preservation of the allowances regulated by the operational chart. The authors suggest optimal combinations of basic parameters of introduction of resource saving technology into production. To adduce an example the authors justify the possibility of shaping and simultaneous hardening of the knife blade during hot rolling between deforming rollers. Energy intensity of the technology suggested is lowered by means of reducing the time for further mechanic processing of the forging by cutting. Practical approbation of the introduced resource saving technology in repair production made it possible to raise the metal utilization rate to 95% and to reduce by 1.2 the production cost of a boning knife as the end product. When manufacturing the parts metal resources are saved due to the fact that irreversible loss of metal in the innovative technology of the boning knives’ production differs a lot from that in the traditional one. Technical and economic calculations adduced in the article show the effectiveness of the research and prove the profit of implementation of the new technology

Stab Injury of the Petrosal Bone: Case Report and Literature Review

Penetrating traumas of the head are generally life-threatening injuries, whose management poses a substantial challenge for emergency department teams. These injuries are characteristically violence-associated and frequently accompanied by damage of essential organs including brain, meninges, large vessels, cranial nerves, eyes, viscerocranium, internal ear, and/or labyrinth. Here, we present an exceptional case of head trauma caused by a knife blade, which was stuck deep inside in the petrous bone. After the extraction of the knife, the patient had very few immediate and no long-term post-traumatic complications. In conclusion, high-end technical equipment as well as an interdisciplinary team of specialized physicians is recommended for the management of penetrating head trauma to optimize the outcome.