Relevant bibliographies by topics / Cushing Formation

Academic literature on the topic 'Cushing Formation'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Cushing Formation"

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Deniz, Mahmut, Zafer Ciftci, and Erdogan Gultekin. "Pharyngoesophageal Suturing Technique May Decrease the Incidence of Pharyngocutaneous Fistula following Total Laryngectomy." Surgery Research and Practice 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/363640.

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Objectives. A pharyngocutaneous fistula (PCF) following total laryngectomy is associated with increased morbidity and severe life threatening complications. We aimed to review our experience with the PCF following total laryngectomy and determine the impact of previously reported risk factors on the development of PCF in our patients.Methods. The medical records of 20 patients who had a total laryngectomy operation were retrospectively analyzed. The association between the proposed risk factors and the incidence of the PCF was investigated.Results. Comparison of the suture techniques used for the closure of the pharynx (either continuous Cushing type or interrupted) yielded that primary interrupted sutures had a significantly higher incidence of PCF formation(p<0.05). Although it was not statistically significant, diabetes mellitus was also associated with increased PCF formation(p>0.05). No significant difference was observed between the PCF and non-PCF groups in terms of other proposed risk factors(p>0.05). Conclusions. The main risk factor associated with PCF was found to be the type of pharyngeal closure technique. A vertical closure with a Cushing type continuous suture may be more successful than interrupted sutures in preventing a PCF.
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Chong, Yau Chun, and Tao Sun Tycus Tse. "A case of candida parapsilosis periprosthetic joint infection: Case report and literature review." Journal of Orthopaedics, Trauma and Rehabilitation 29, no. 1 (February 23, 2022): 221049172210758. http://dx.doi.org/10.1177/22104917221075826.

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A 76 year old female, with a background history of eczema and iatrogenic Cushing syndrome, received a right total knee replacement for her knee osteoarthritis. In the early post-operative period, a small amount of discharge was noted from the surgical wound. The wound swab culture of the discharge yielded candida species. It was regarded as contamination initially. Half year later, she presented with a subcutaneous abscess around the right knee. Aspiration and culture confirmed infection of Candida parapsilosis. The patient was treated conservatively with fluconazole because she had initially refused operative treatment. The infection progressed to abscess formation afterward. A two-stage revision arthroplasty with cement spacer was performed subsequently. In addition, we have reviewed the literature regarding fungal periprosthetic joint infection.
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Zlatina, Zheleva, Gergana Petkova, Vanya Ivanova, and Svetla Petrova. "EPONYMS IN THE FIELD OF MEDICINE AND PAEDIATRIC DENTAL MEDICINE IN BULGARIAN AND ENGLISH." Opera in onomastica, no. 24 (December 28, 2021): 76–99. http://dx.doi.org/10.18524/2410-3373.2021.24.248320.

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Introduction. Eponyms have been an inseparable part of medicine ever since the science exists. The need to name diseases and conditions after the physicians who came upon them and explored them arose (e.g., Addison’s disease, Cushing syndrome etc). This method of term formation continues to be employed even nowadays and its main advantage is that it facilitates remembering the condition. The purpose of the present paper is to establish the main principles of formation of eponyms and to compare them within the Bulgarian, English and Latin terminology. Another comparison which is intended is the use of eponyms in clinical medicine and clinical paediatric dental medicine. Background and motivations. The purpose of eponyms is to name diseases and conditions and to facilitate remembering. However, there are underlying principles of term formation and usage in the different fields of medicine which need to be clarified and traced. Methodology. The main methods used are lexicographical excerption and comparative analysis. The eponyms are classified according to the manner of their formation and usage. The expected results are related to the differences in the use of eponyms in the medical terminologies of Bulgarian and English clinical setting and to compare those to their source languages- Latin and ancient Greek.
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Kyo, Chika, Takeshi Usui, Rieko Kosugi, Mizuki Torii, Takako Yonemoto, Tatsuo Ogawa, Masato Kotani, et al. "ARMC5 Alterations in Primary Macronodular Adrenal Hyperplasia (PMAH) and the Clinical State of Variant Carriers." Journal of the Endocrine Society 3, no. 10 (July 23, 2019): 1837–46. http://dx.doi.org/10.1210/js.2019-00210.

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Abstract Context Primary macronodular adrenal hyperplasia (PMAH) is a rare type of Cushing or subclinical Cushing syndrome and is associated with bilateral multinodular formation. ARMC5 is one of the responsible genes for PMAH. Objectives This study was performed to identify the genotype-phenotype correlation of ARMC5 in a cohort of Japanese patients. Patients and Methods Fourteen patients with clinically diagnosed PMAH and family members of selected patients were studied for ARMC5 gene alteration and clinical phenotype. The associated nonadrenal tumor tissues were also studied. Results Of fourteen patients with PMAH, 10 had pathogenic or likely pathogenic variants of ARMC5. We found two variants. Five unrelated patients had identical variants (p.R619*). In two patients, the variant was found in offspring with the asymptomatic or presymptomatic state. Six of ten patients who tested positive for the ARMC5 pathogenic or likely pathogenic variant carried nonadrenal tumors; however, no loss of heterozygosity (LOH) or second hit of the ARMC5 gene was evident. The ARMC5 variant–positive group showed a significantly higher basal cortisol level. Furthermore, age-dependent cortisol hypersecretion was seen in the ARMC5 variant–positive group. Conclusions ARMC5 pathogenic variants are common (71%) in Japanese patients with PMAH. p.R619* might be a hot spot in Japanese patients with PMAH. Asymptomatic or presymptomatic pathogenic variant carriers were found among the family members of the patients. Although 50% of ARMC5 variant carriers had nonadrenal neoplastic lesions, no LOH or second hit of ARMC5 in the tumor tissues was evident. The ARMC5 variant–positive mutant group showed a higher basal cortisol level than the negative group.
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Di Dalmazi, Guido, Henri J. L. M. Timmers, Giorgio Arnaldi, Benno Küsters, Marina Scarpelli, Kerstin Bathon, Davide Calebiro, Felix Beuschlein, Ad Hermus, and Martin Reincke. "Somatic PRKACA Mutations: Association With Transition From Pituitary-Dependent to Adrenal-Dependent Cushing Syndrome." Journal of Clinical Endocrinology & Metabolism 104, no. 11 (July 5, 2019): 5651–57. http://dx.doi.org/10.1210/jc.2018-02209.

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Abstract Context Prolonged adrenal stimulation by corticotropin, as in long-standing Cushing disease (CD), leads to diffuse to nodular hyperplasia. Adrenal functional autonomy has been described in a subset of patients with CD, leading to the hypothesis of transition from ACTH-dependent to ACTH-independent hypercortisolism. Objective With the consideration that the catalytic α subunit of protein kinase A (PKA; PRKACA) somatic mutations are the most common finding in adrenal adenomas associated with ACTH-independent Cushing syndrome, our aim was to analyze PRKACA mutations in adrenals of patients with persistent/long-standing CD. Design Cross-sectional. Setting University hospital. Patients Two patients with long-standing CD and suspicion of coexistence of autonomous adrenal hyperfunction, according to pre and postoperative evaluations, were selected for this study, following an intensive literature search and patient-chart reviewing. Intervention Clinical data were analyzed. DNA was extracted from adrenal tissue for PRKACA sequencing. PKA activity was assayed. Main Outcome Measure PRKACA somatic mutations. Results Both patients showed mutations of PRKACA in the macronodule in the context of micronodular adrenal hyperplasia. One patient harbored the previously described p.Leu206Arg substitution, whereas a p.Ser213Arg missense variation was detected in the adrenal nodule of the second patient. No mutations were detected in the adjacent adrenal cortex of the second patient. In silico analysis predicts that p.Ser213Arg can interfere with the interaction between the regulatory and catalytic subunits of PKA. Conclusions Our study shows that PRKACA somatic mutations can be found in adrenal nodules of patients with CD. These genetic alterations could represent a possible mechanism underlying adrenal nodule formation and autonomous cortisol hyperproduction in a subgroup of patients with long-standing CD.
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Kassam, Amin, Ricardo L. Carrau, Carl H. Snyderman, Paul Gardner, and Arlan Mintz. "Evolution of reconstructive techniques following endoscopic expanded endonasal approaches." Neurosurgical Focus 19, no. 1 (July 2005): 1–7. http://dx.doi.org/10.3171/foc.2005.19.1.9.

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Harvey Cushing first popularized the transsphenoidal route to the sella turcica, and Jules Hardy subsequently refined it by adding the operating microscope. Over the ensuing decades, attempts at extending the application of this approach have been advanced by Edward Laws and others. With the evolution of endoscopic approaches, the natural expansion of their use to intradural lesions followed. For the expanded endonasal approach to become a viable option, the paramount concerns surrounding consistent reconstruction of the dura mater must be overcome. In this review the authors chronicle the evolution of the reconstruction technique they currently use after performing expanded endonasal approaches. They also report the use of a balloon stent to buttress the reconstruction and counter the effects of graft migration and cerebrospinal fluid fistula formation. The technique described in this report represents an important step forward in the reconstruction of defects resulting from expanded endonasal approaches.
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Horşia, Dragoş. "Medulloblastoma in Adulthood." Acta Medica Transilvanica 26, no. 3 (September 1, 2021): 52–54. http://dx.doi.org/10.2478/amtsb-2021-0051.

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Abstract Defined as a tumour with increased malignancy potential in childhood, medulloblastoma was first reported in the literature by Percival Bailey and Harvey Cushing in 1925. Scientific studies over the years have shown that this type of tumour represents about 20% of all intracranial tumours encountered in childhood, their percentage decreasing with advancing age. The genetic factor plays an important part in the appearance of medulloblastoma; there are certain diseases, in the patient’s history, that can be associated with this type of tumour. Here, we can specify Turcot syndrome (an autosomal recessive disease, rarely encountered) or basal cell carcinoma syndrome. This article presents the case of a young patient (41-year-old) suffering from a cerebellar tumour formation that turned out to be, after histopathological examination, a medulloblastoma. In practice we can find several types of medulloblastoma (desmoplastic or nodular, anaplastic, classical or undifferentiated). In what follows I will try to highlight a few aspects of a classic medulloblastoma.
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Hope, T. "TP3-11 Sir geoffrey jefferson, a father of the SBNS, a remarkable life." Journal of Neurology, Neurosurgery & Psychiatry 90, no. 3 (February 14, 2019): e21.1-e21. http://dx.doi.org/10.1136/jnnp-2019-abn.65.

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ObjectivesThe foundation of a Society of Neurological Surgeons was Jefferson`s idea. How did this come about? The objective is to research this period of our history and its development.DesignA review of papers and articles held in the University of Manchester, The University of Oxford and abstracts from a biography of Jefferson by Peter Schurr, enables an historic presentation to the SBNS and the ABN.SubjectsIn 1926 Sir Geoffrey Jefferson was closely connected to the leading minds in British neurology and neurological surgery. His friendship and correspondence with Cushing was a major force in his drive for a specialist society. These players on the neurosurgical stage are the subjects of this presentation.MethodsAs in the design, the author will survey all available material including photography and handwritten manuscripts.ResultsOn the very next day after being appointed a consultant neurological surgeon at the Manchester Royal Infirmary, Jefferson arranged a meeting at the Athenaeum Club to consider the formation of our society. This was held on December the 2nd 1926 and the first formal scientific meeting was held on the 3rd at Queen Square!ConclusionsThe formation of this small society was crucial in presenting British neurosurgery as a specialty in its own right to medicine in the United Kingdom. No other neurosurgical society existed in Europe at this stage. Jefferson is indeed the father figure of our society today.
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Kürschner, Harald. "The subalpine thorn-cushion formations of western South-West Asia: ecology, structure and zonation." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 89 (1986): 169–79. http://dx.doi.org/10.1017/s0269727000009003.

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SynopsisThe distribution and ecological characteristics of the thorn-cushion formations (Tragacanthic vegetation) in the western part of SW Asia are discussed. The typical structure of this formation is illustrated by 2 examples from the mountains of the Antilebanon. These show a clear zonation in relation to the growth form. This, and the available micro-climatological data, show that thorn-cushions reach their ecological optimum on windswept slopes and hill tops. This growth form is obviously an adaptation for sites exposed to strong winds. Taxa with this growth form have a competitive advantage in such habitats.
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CHOU, PEI-HSI, YOU-LI CHOU, CHOE-JAN CHIANG, TING-SHENG LIN, and SHU-ZON LOU. "BIOMECHANICAL ANALYSES OF STRESS DISTRIBUTION WITHIN THE SEATED BUTTOCK AND CUSHION." Biomedical Engineering: Applications, Basis and Communications 14, no. 06 (December 25, 2002): 269–72. http://dx.doi.org/10.4015/s1016237202000383.

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The elderly wheelchair users frequently encountered the prevalence of pressure sore, also known as decubitus, since they have to be seated in the wheelchair for daily activities. The major cause induced the formation of pressure sore was that the soft tissues were over-stressed. The purpose of this study was to provide the information about internal stresses of soft tissues and establish a simplified finite element model to simulate the behavior of the interface between human buttock and cushion. Computational stresses were verified by comparing the buttock-cushion interface pressures, which was measured with Q.A. pressure pads. The displacement of the cushion was also validated with the experimental results of buttock measuring system. Two cushion geometries, fat and contoured, were adopted in this study to explore the effects on stress distributions. The results showed that the simplified finite element model was consistent with the experimental data. Contoured cushions had better stress distribution and lower interface stress.
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Dissertations / Theses on the topic "Cushing Formation"

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Dixit, Bhanumathi (Bonnie). "A temperature monitoring cushion for preventing the formation of ischial decubitus ulcers." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/14928.

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Anderson, Gregory A. "Endoglin is dispensable for blood vessel morphogenesis but is required for endocardial cushion formation in the developing mouse embryo." 2008. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=771977&T=F.

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Books on the topic "Cushing Formation"

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Henderson, Deborah J., Bill Chaudhry, and José Luis de la Pompa. Development of the arterial valves. Edited by José Maria Pérez-Pomares, Robert G. Kelly, Maurice van den Hoff, José Luis de la Pompa, David Sedmera, Cristina Basso, and Deborah Henderson. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198757269.003.0018.

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The arterial valves guarding the entrances to the aorta and pulmonary trunk have many similarities to the mitral and tricuspid valves in the atrioventricular region of the heart. Despite these similarities, there are significant differences in the formation and structure of the arterial and atrioventricular valves. The most fundamental of these relate to the lineage origins of the cells forming the primitive cushions. Although the fate of the different lineages remains unclear, each makes a permanent contribution to the mature valve. Arterial valve formation is intrinsically linked to cushion formation and outflow tract septation; therefore abnormalities in these processes have a profound impact on development of the valve leaflets. In this chapter we highlight the main differences in the development and structure of the arterial valves, compared with the atrioventricular valves, show how abnormalities in these developmental processes can result in arterial valve anomalies, and discuss controversies within the literature.
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Book chapters on the topic "Cushing Formation"

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Benson, D. Woodrow. "Formation of Endocardial Cushions and Valves." In Cardiovascular Development and Congenital Malformations, 53–54. Malden, Massachusetts, USA: Blackwell Publishing Ltd, 2007. http://dx.doi.org/10.1002/9780470988664.part3.

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Kockx, Mark M. "Intimal Cushion Formation and Diffuse Intimal Thickening in Human Lower Limb Arteries." In Spontaneous and Induced Intima Formation in Blood Vessels, 9–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-662-22430-4_2.

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Yamagishi, Toshiyuki, Yuji Nakajima, Katsumi Ando, and Hiroaki Nakamura. "Msx1 Expression During Chick Heart Development: Possible Role in Endothelial-mesenchymal Transformation During Cushion Tissue Formation." In Cardiovascular Development and Congenital Malformations, 69–71. Malden, Massachusetts, USA: Blackwell Publishing Ltd, 2007. http://dx.doi.org/10.1002/9780470988664.ch17.

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"The Cushing mission to Macao and US imperial expansion in nineteenth- century Asia HE SIBING." In Macao - The Formation of a Global City, 157–76. Routledge, 2013. http://dx.doi.org/10.4324/9780203797242-18.

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Graham, Alan. "Setting the Goal: Modern Vegetation of North America Composition and Arrangement of Principal Plant Formations." In Late Cretaceous and Cenozoic History of North American Vegetation (North of Mexico). Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195113426.003.0004.

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Vegetation is the plant cover of a region, which usually refers to the potential natural vegetation prior to any intensive human disturbance. The description of vegetation for an extensive area involves the recognition and characterization of units called formations, which are named with reference to composition (e.g., coniferous), aspect of habit (deciduous), distribution (western North America), and climate, either directly (tropical) or indirectly (tundra). Further subdivisions are termed associations or series, such as the beech-maple association or series within the deciduous forest formation. Formations and associations constitute a convenient organizational framework for considering the development of vegetation through Late Cretaceous and Cenozoic time. For this purpose seven extant plant formations are recognized for North America: (1) tundra, (2) coniferous forest, (3) deciduous forest, (4) grassland, (5) shrubland/chaparral- woodland- savanna, (6) desert, and (7) elements of a tropical formation. Several summaries are available for the modern vegetation of North America, including Barbour and Billings (1988), Barbour and Christensen, Kuchler (1964), and Vankat (1979). The following discussions are based primarily on these surveys. Tundra (Fig. 1.2) is a treeless vegetation dominated by shrubs and herbs, and it is characteristic of the cold climates of polar regions (Arctic tundra) and high-altitude regions (alpine tundra). In the Arctic tundra a few isolated trees or small stands may occur locally, such as Picea glauca (white spruce), but these are always in protected habitats. The Arctic region experiences nearly continuous darkness in midwinter, and nearly continuous daylight in midsummer. There is a short growing season of only 6-24 weeks; this accounts, in part, for the fact that 98% of all Arctic tundra plants are perennials (Vankat, 1979). Strong winds are another feature of the Arctic landscape, often exceeding 65 km/h for 24 h or more. They likely account for the frequency of rosettes, persistent dead leaves, and the cushion growth form, in the center of which wind velocities may be reduced by 90%. The harsh growing conditions also result in leaves of the microphyllous size class being comparable to those of desert plants. Vegetative reproduction and self-pollination is common, and phenotypic plasticity is high among Arctic tundra plants.
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M. Ntomba, Sylvestre, Christelle R. Magnekou Takamte, Dieudonné Bisso, and Joseph Mvondo Ondoa. "Construction Materials and Dam Foundation While Memve’ele Dam Building in the Craton’s Region of South Cameroon." In Engineering Geology. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.93758.

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This chapter mainly focuses on engineering geology for dam construction from the Memve’ele region in Cameroon. Here, it deals with geotechnical and geological proprieties of both construction and dam foundation materials. This study is done at the aim to ensure that these materials need to be improved and how they have been used during dam construction. Field investigations, borehole information, density and seismic velocity measurements have been used, and results indicate that soil deposits have slightly clay content, mechanically well for dam construction and display a weak thickness layer particularly on the dam site. These conditions suggest that soil materials can be used as construction (cushion, transition layers, etc.) and foundation materials after few amendments. Ntem Formations appear weathered and fractured sometimes, though their mechanical behaviors display a good character for civil applications. However, engineering processes have been used to improve it by GIN (Grouting Intensity Number) methods. These formations have been used as construction (rip rap crushing aggregate, etc.) and dam foundation materials. Thus, this chapter contributes to highlight materials and dam foundation conditions which are crucial criteria encountered in the dam with emphasis on both theoretical study and practical application during dam construction.
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Conference papers on the topic "Cushing Formation"

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Pallerla, Vinay Kumar, and Mohamed Samir Hefzy. "Relationship Between the Frictional Shear Stresses and the Normal Pressure on the Buttocks While Lying on a Spine Board." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-11814.

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Abstract Cushions have been used on spine boards to reduce the interface pressure acting on the skin and thus prevent the formation of pressure ulcers. Several studies have focused on determining how using different types of cushions can reduce the normal interface pressure on the buttocks while lying on the spine boards. On the other hand, and while it has been agreed upon that the shear stresses contribute to the formation of pressure ulcers, this role has not been understood or quantified. The purpose of this work is to use 3-D finite element modeling to determine the contact frictional shear stresses at the buttocks while an individual is lying on a spine board when cushions of various stiffnesses are used. The Zygote Solid 3D Male Human Anatomy model was used to construct a 3D CAD model of a section of the human body in the pelvic region. Skin, fat, muscles and bones were identified in the model. The Zygote SolidWorks model, the HyperMesh finite element preprocessor, and the ABAQUS software were used to create the finite element model. Bones were considered as an elastic isotropic material whereas skin, fat and muscles were modeled using Hyperelastic Neo-Hookean materials. Results were obtained to find the effects of body weight on the shear stresses while a person is lying flat with his buttocks contacting the spine board. The results indicate that frictional skin shear stresses cannot be ignored since they were found to be, and depending on the cushion material, about 15% to 35% of the maximum normal pressure. We propose, and for the first time, a relationship to estimate the maximum shear stresses at the buttocks in terms of the maximum normal pressure for different Young’s moduli of cushions. These results can also be used as a guide to select cushion material that minimize normal and shear interface stresses.
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Nuthi, Pavan, Wei Carrigan, Charu Pande, and Muthu B. J. Wijesundara. "Control Implementation for Real-Time Pressure Adjusting Seat Cushion to Prevent Pressure Ulcers." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-86210.

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External mechanical loading is a major contributing factor in pressure ulcer formation and is a major health concern for wheelchair users. Seat cushion technologies are employed to reduce the magnitude and duration of this loading using soft seating surfaces and pressure offloading techniques. However, pressure offloading often results in the creation of new high pressure points which can still lead to pressure ulcer formation. In order to mitigate the issue, a novel closed-loop controlled seat cushion system is developed with sensorized air cell arrays which can continuously monitor pressure profile of a seated person and modulate this interface pressure. This paper presents the control implementation of this seat cushion system using a novel scheduling control algorithm based on bang-bang control as well as the corresponding electronics and pneumatic layout. The effectiveness of the system is demonstrated for real-time pressure mapping, offloading, and redistribution of seating interface pressure and its capabilities of instantaneous local pressure measurement as well as automated pressure modulation are verified.
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Erel, Veysel, Pavan Nuthi, Yixin Gu, Himanshu Purandare, Nischita Haldipurkar, and Muthu B. J. Wijesundara. "Numerical Modeling of Air Cell Cushion and Estimation of Shear Force Distribution at Sitting Interface." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71765.

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Abstract Shear forces at sitting interfaces are a major contributing factor in pressure injury formation. However, measuring shear forces throughout the sitting interface is not possible due to a lack of shear sensors for this application. This paper presents a finite element simulation model for an automated air cell smart seat cushion that can predict shear forces at the interface. The model was developed and validated by comparing static analyses to experimental data, with respect to interface pressure, internal air cell pressure, and interaction forces. The real-time experimental data in this study was generated from three different sources: 1) A commercial seating pressure mat yields an interface pressure map, 2) The smart seat cushion yields the internal pressure of air cells, and 3) The rigid cushion loading indenter yields the immersion into the cushion and the force applied on the cushion. The validated simulation model was used to evaluate shear force data at the sitting interface corresponding to different loading scenarios.
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Mandala, Mahender A., Kenneth Lassman, and Kenneth J. Fischer. "Active Cushion Patterns and Alternating Inflation/Deflation Cycle Times Can Influence Seating Interface Pressures." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80902.

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Intermittent pressure relief has been recommended as a means to lower the risk of pressure ulcer (PU) development [1]. Continuous pressure over skin surface is one of the most significant factors, and in most cases the only requisite factor, that may result PUs. Thus, using an active seat cushion (i.e., a cushion that cyclically changes the area of exposure to pressure) seems like a logical strategy to lower the risk of PU formation in the chair-bound population.
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Nuthi, Pavan, and Muthu B. J. Wijesundara. "Modeling and Simulation of Aircell Actuator Seat Cushion With Pneumatic Line Lag and Capacitative Effects." In ASME 2020 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/dscc2020-3232.

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Abstract This article presents the development of a hybrid model with pneumatic lag effects for the smart seat cushion which can be extended to any active aircell cushion. Smart seat cushion is one such rehabilitation device which reduces the risk of pressure injury formation by automatically performing repositioning exercises for wheelchair users. Operation of the smart seat cushion device can be greatly enhanced by accurate prediction of pneumatic line lag during its various modes of operation. The proposed model combines a linear model from literature to capture the effects of pneumatic line lag and a bang-bang scheduling controller to enable efficient use of pneumatic components in the smart seat cushion device. The resulting simulation is validated by conducting multiple runs of uniform inflation experiment with the device, and comparing the closed loop behavior of the model. The hybrid modeling allows accurate prediction of pneumatic line lag in the smart seat cushion during various modes of redistribution and offloading. The modeling accuracy and the prediction of switching times for discrete states can be improved by data sampled at a higher rate from the device.
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Yeganehdoust, F., I. Karimfazli, and A. Dolatabadi. "Numerical Analysis of Droplet Impact on a Smooth Slippery Surface." In ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83282.

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Spontaneous bouncing of a droplet that impacts a surface is a mechanism that occurs for the moderate range of droplet impact velocities and is caused by the formation of a stable air layer (cushion) between the droplet and the surface. This bouncing behavior is more pronounced on Lubricant Impregnated Surfaces (LISs) inspired by the natural non-wetting surface of the pitcher plant, which relies on the stable formation of a thin lubricant film across its surface. In this study, we performed modeling of the water-oil–air interfacial surfaces using the volume of fluid (VOF) methodology to simulate the impact of a water droplet onto a lubricant smooth surface with an oil as the lubricant. To resolve the effects of the air surrounding the droplet, computational cells were extensively small to capture the presence of the sub-micron layer of air trapped underneath the droplet during the impact. The model was able to capture the initiation and subsequent effect of the air cushion on the droplet hydrodynamics. We found that the stability of the air cushion and the impact dynamics are independent of the oil viscosity for specific thicknesses of lubricant layers, whereas the impact conditions such as velocity and droplet properties played a significant role on the outcome of droplet impact. Hence, the dynamics of a droplet falling on a specific thickness of oil film was influenced by the squeezed air trapped between the two immiscible fluid (water and oil). In addition, the formation of high pressure dimple region was evident, which in some cases lead to entrapment of the air bubble. Finally, we validated the results with the existing experimental data in the literature.
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Зайнагабутдинов, Булат Айратович. "FEATURES OF HYDRODYNAMIC MODELING OF DEVELOPMENT OF UNDERGROUND GAS STORES IN CRACKED POROUS RESERVOIRS." In Научные исследования в современном мире. Теория и практика: сборник избранных статей Всероссийской (национальной) научно-практической конференции (Санкт-Петербург, Май 2021). Crossref, 2021. http://dx.doi.org/10.37539/nitp316.2021.56.36.015.

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При разработке подземных хранилищ газа наблюдается образование конусов подошвенной воды, что ведет к самозадавливанию скважин. Для борьбы с данным явлением необходимо определять оптимальные объемы буферного газа. В данной статье представлены результаты моделирования данной технологии в гидродинамическом симуляторе. In the development of underground gas storage facilities, the formation of cones of bottom water is observed, which leads to self-suppression of wells. To combat this phenomenon, it is necessary to determine the optimal volumes of cushion gas. This article presents the results of modeling this technology in a hydrodynamic simulator.
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Carrigan, Wei, Pavan Nuthi, Charu Pande, Caleb P. Nothnagle, and Muthu B. J. Wijesundara. "A Pressure Modulating Sensorized Soft Actuator Array for Pressure Ulcer Prevention." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-68191.

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Pressure ulcers are a serious reoccurring complication among wheelchair users with impaired mobility and sensation. It is postulated that external mechanical loading, specifically on bony prominences, is a major contributing factor in pressure ulcer formation. Prevention strategies mainly center on reducing the magnitude and duration of external forces acting upon the body. Seat cushion technologies for reducing pressure ulcer prevalence often employ soft materials and customized cushion geometries. Air cell arrays used in time-based pressure modulation techniques are seen as a promising alternative; however, this approach could be further enhanced by adding real-time pressure profile mapping to enable automated pressure modulation customizable for each user’s condition. The work presented here describes the development of a prototype support surface and pressure modulation algorithm which can monitor interface pressure as well as automatically offload and redistribute concentrated pressure. This prototype is comprised of arrays of sensorized polymeric soft air cell actuators which are modulated by a pneumatic controller. Each actuator’s pressure can be changed independently which results in a change to the interface pressure allowing us to offload targeted regions and provide local adjustment for redistribution. The pressure mapping, redistribution, and offloading capabilities of the prototype are demonstrated using pressure modulation algorithms described here.
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Graham, Robin M., and Martine LaBerge. "Alternative Bearing Surfaces for Arthroplasty." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0357.

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Abstract Elastomeric materials have been suggested for use in total joint arthroplasty as an alternative to ultra high molecular weight polyethylene (UHMWPE).1–2 As a bearing material operating under mixed lubrication regimes, UHMWPE is subject to wear. Wear particles cause an adverse tissue reaction eventually resulting in loosening of the prosthesis. The modulus of elasticity of the UHMWPE does not allow sufficient deformation of asperities which would increase the film thickness between the bearing surfaces and prevent wear. Elastomers, however, can deform under pressure and enhance lubrication by the formation of a fluid film through elastohydrodynamic and micro-elastohydrodynamic lubrication.3 However, elastomeric coatings are subject to fatigue and debonding from their rigid substrates. To promote fluid film lubrication and prevent failure associated with the use of soft elastomeric bearings, a “true cushion” bearing was designed consisting of a soft elastomer sandwiched between a thin rigid coating and a thick rigid substrate of similar chemistry. This study was aimed at characterizing the frictional behavior of this construct in a lubricated environment as compared to UHMWPE and a non-coated soft elastomeric bearing.
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Al Sheidi, Ali Salim, Hatim Abdul Raheem Al Balushi, Zahran Ahmed Al Rawahi, Ahmed Saleem Al Harrasi, Deutra Mansur, Mohammed Malallah Al Farsi, Hilal Sultan Al Rubaiey, Nadir Ali Al Harrasi, Manish Kumar Choudhary, and Cesar Orta. "Step Change in Controlling the Gas-Cap in Highly Depleted and Fractured Formation." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211490-ms.

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Abstract This paper discusses the successful trials of a new approach to drill Formation-A Reservoir in Field-A. Field-A is one of the most challenging fields in the Sultanate of Oman due to the presence of a gas cap combined with total losses encountered when penetrating a highly fractured and depleted shallow reservoir. Several unsuccessful attempts had been made in the past to overcome the challenge of total losses using conventional methods (LCM, cement plug, etc). Since then, it was agreed to stop the attempts to cure these losses and control these wells instead with a unique well control situation through dynamic filling, which is a continuous pumping of water (70 - 120 m3/hr depending on the hole size) in the annulus. This method acts as primary barrier by having higher downward velocity of water than upward velocity of gas. However due to large amounts of water being pumped into the reservoir, it caused a commercial impact on oil production due to water flow back in production and large number of emissions (12 T/year/well) from this unproductive operation. The other downside of dynamic fill method is the risk of well process safety due to it relies heavily on human behavior and actions. There are many cases where the filling was interrupted by different factors. The team carried out a study on the existing process of drilling 8 ½" and 6 ⅛" holes with a view of eliminating the need for dynamic fill practice. This led to the selection of Nitrogen Cap Drilling (NCD), which is a variation of the Managed Pressure Drilling technique (MPD) technique. NCD is a closed-loop drilling system with no returns to surface based on the presence of a nitrogen cushion establishing the communication between surface and a reduced liquid column in the annulus. The well is continuously monitored, and the annulus pressure is controlled through the wellhead pressure and a balanced fluid level without the need for filling while drilling with total losses. In 2021, the team delivered 2 (two) trial wells with NCD technique successfully without interruption and saving approximately 8,300 m3 of water compared to conventional drilling. NCD allows the pneumatic pressure communication via a pressurized nitrogen column on top of the Heavy Annulus Mud (HAM) balancing the formation pressure. The positive wellhead pressure allows better control of the well behavior and monitor potential gas migration. A positive injectivity test confirmed the applicability of the NCD technique to contain the drilling fluid and drive the cuttings back into the formation. During the drilling process, well site water is injected down the drill string and HAM is injected intermittently in the annulus form the back side of the RCD based on the annulus surface pressure changes related to the gas migration. Tripping out of hole was done using NCD keeping the well balanced and monitored to avoid gas migration to surface. This technology is a step change in our journey to address drilling high-risk Formation-A gas-cap wells in Oman with the NCD concept. It addresses the Well Process Safety concerns, generates a huge value by accelerating oil production from the drilled wells without affecting the nearby ones and finally improves the environment sustainability goals in PDO’s drilling operations.
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