The effect of cortical thickness and thread profile dimensions on stress and strain in bone-anchored implants for amputation prostheses

Skeletal attachment of limb prostheses ensures load transfer between the prosthetic leg and the skeleton. For individuals with lower limb amputation, these loads may be of substantial magnitude. To optimize the design of such systems, knowledge about the structural interplay between implant design features, dimensional changes, and material properties of the implant and the surrounding bone is needed. Here, we present the results from a parametric finite element investigation on a generic bone-anchored implant system of screw design, exposed to external loads corresponding to average and high ambulatory loading. Of the investigated parameters, cortical thickness had the largest effect on the stress and strain in the bone-anchored implant and in the cortical bone. 36%–44% reductions in maximum longitudinal stress in the bone-anchored implant was observed as a result of increased cortical thickness from 2 mm to 5 mm. A change in thread depth from 1.5 mm to 0.75 mm resulted in 20%–22% and 10%–18% reductions in maximum longitudinal stress in the bone-anchored implant at 2 mm and 5 mm cortical thickness respectively. The effect of changes in the thread root radius was less prominent, with 8% reduction in the maximum longitudinal stress in the bone-anchored implant being the largest observed effect, resulting from an increased thread root radius from 0.1 mm to 0.5 mm at a thread depth of 1.5 mm. Autologous transplantation of bone tissue distal to the fixture resulted in reductions in the longitudinal stress in the percutaneous abutment. The observed stress reduction of 10%–31% was dependent on the stiffness of the transplanted bone graft and the cortical thickness of surrounding bone. Results from this investigation may guide structural design optimization for bone-anchored implant systems for attachment of limb prostheses

Low plasticity burnishing improves fretting fatigue resistance in bone-anchored implants for amputation prostheses

Fretting fatigue is a common problem for modular orthopedic implants which may lead to mechanical failure of the implant or inflammatory tissue responses due to excessive release of wear debris. Compressive residual stresses at the contacting surfaces may alleviate the problem. Here we investigate the potential of a surface enhancement method known as low plasticity burnishing (LPB) to increase the fretting fatigue resistance of bone-anchored implants for skeletal attachment of limb prostheses. Rotation bending fatigue tests performed on LPB treated and untreated test specimens demonstrate that the LPB treatment leads to statistically significantly increased resistance to fretting fatigue (LPB treated test specimens withstood on average 108,780 load cycles as compared with 37,845 load cycles for untreated test specimens, p = 0.004). LPB treated test specimens exhibited less wear at the modular interface as compared with untreated test specimens. This surface treatment may lead to reduced risk of fretting induced component failure and a reduced need for revision of implant system componentry

PELATIHAN PENGENALAN CACAT LAS STANDAR INTERNASIONAL DI SMK IMMANUEL JLN.GATOT SUBROTO NO 325 MEDAN PROVINSI SUMATERA UTARA TAHUN 2023

Jurusan Teknik Mesin Politeknik Negeri Medan (POLMED) mempunyai peralatan praktek dan laboratorium pengelasan (welding) bertaraf internasional. Sejalan dengan kemajuan peralatan ini, cukup banyak staf pengajar pada program studi ini yang sudah memiliki sertifikat pengajar pada bidang pengelasan. Sosialisasi pengelasan program studi ini sudah memperoleh pengakuan dari Lembaga profesi Institute International Welding (IIW) dan The Welding Institute (TWI), sehingga Jurusan Teknik Mesin sudah menjadi Tempat Uji Kompetensi (TUK) sertifikasi Internasional IIW dan TWI. Pengusul program pelatihan pengenalan cacat las standar internasional ini sudah memiliki sertifikat CSWIP (Certificate Scheme Welding Inspection Personnel) 3.0 dari The Welding Institute. SMK IMMANUEL MEDAN memiliki bidang pelatihan kursus Pengelasan, ini berkaitan dengan pembuatan kerangka (chasis & body) kenderaan. Peserta yang mengikuti program ini cukup baik prestasinya dan dipersiapkan dapat memasuki dunia kerja setelah di nyatakan lulus dengan bukti sertifikat. Adalah sangat beralasan SMK IMMANUEL MEDAN ini menerima tawaran program pelatihan pengenalan cacat las standar internasional yang di selengarakan oleh dosen Jurusan Teknik Mesin Politeknik Negeri Medan (POLMED). khusunya untuk mengadakan Sosialisasi inspeksi pengelasan berdasarkan standar TWI. Pengetahuan ini akan mempersiapkan calon lulusan SMK Immanuel untuk memasuki pekerjaan pada bidang pengelasan. Program ini sangat relevan dengan dunia kerja dewasa Dengan pelatihan ini peserta SMK  akan memperoleh wawasan bagaimana hasil pengelasan yang memenuhi standar TWI yang merupakan standar yang digunakan secara luas di dunia internasional hal ini di dukung dengan para dosen yang melakukan pengabdian di atas sudah berpengalaman dan memiliki sertifikat dalam pelatihan CSWIP 3.0 (welding Inspector)  dalam penggunaan alat ukur welding guage yang akan di sumbangkan kepada SMK Immanuel tersebut. Melalui program ini telah disumbangkan juga modul inspeksi pengelasan dan welding gauge nya sehingga para peserta SMK dapat menggunakannya pada waktu mendatang

Analysis of Water Quality Pollution Index Asahan river in Tanjungbalai City

The Asahan River, located in the Tanjungbalai city area, is used for plantation, agriculture, animal husbandry activities, toilet washing facilities, hospitals, hotels, settlements, and industry causing the decrease water quality of Asahan River. The purpose of this study was to analyze the water quality and status of the Asahan River water quality in the Tanjungbalai City Area and develop a pollution control  strategy that needs to be implemented to prevent a decrease in the Asahan River water quality in the Tanjungbalai City Area. Purposive sampling technique as used to determine the sampling station. In this study, there were 6 sampling stations based on the activities of the local community with 3 repetitions of sampling. The data analysis techniques from this study are Water Quality Analysis using the Pollution Index (IP) Method and Water Pollution Control Strategy Analysis. The results of water quality analysis based on the pollution index on Asahan river water in Tanjungbalai City show that the average water pollution index is in the moderately polluted category. The maximum of river water pollution index results were at station 2 is 9,086 and the minimum of river water pollution index results were at station 5 is 6,111.Water pollution occurs due to the parameters of phosphate, detergent, oil and grease, and total coliform which have exceeded the quality standard threshold based on Government Regulation of the Republic of Indonesia Number 21 of the year 2022 concerning Management of Water Quality and Control of Class I Water Pollution. Keywords: Asahan River Water pollution Index Water Qualit

Experiences of hospice dementia care: A qualitative study of bereaved carers and hospice clinicians

BACKGROUND: Nearly 50 million people worldwide have dementia and the increasing numbers requiring end-of-life and palliative care, has led to national efforts to define standards of care for this patient group. Little research, however, has been done to date about the experience of hospice care for people with dementia accessing these services. This study explores the views of hospice dementia care for bereaved carers of people with dementia and hospice clinicians. METHODS: We used purposive sampling for participant recruitment. Semi-structured qualitative interviews were conducted with bereaved carers and hospice clinical staff. Interviews were audio recorded and the transcriptions were analysed through thematic analysis. A total of 12 participants were interviewed from one service in the Northwest region in the UK. All were female and white British. RESULTS: Participants described their experience of hospice dementia care in three main themes: Pre-access to service, roles and responsibility within hospice care, ease and difficulty of last period of end-of-life care. CONCLUSION: Rapid response teams delivering hospice home care could represent a better option to inpatient care and may be preferred by patients. This type of service, however, may require joined-up care with other community services, and this type of care needs to be considered and planned. Future studies should evaluate this type of community care

A polysaccharide utilization locus from the gut bacterium dysgonomonas mossii encodes functionally distinct carbohydrate esterases

The gut microbiota plays a central role in human health by enzymatically degrading dietary fiber and concomitantly excreting short chain fatty acids that are associated with manifold health benefits. The polysaccharide xylan is abundant in dietary fiber but noncarbohydrate decorations hinder efficient cleavage by glycoside hydrolases (GHs) and need to be addressed by carbohydrate esterases (CEs). Enzymes from carbohydrate esterase families 1 and 6 (CE1 and 6) perform key roles in xylan degradation by removing feruloyl and acetate decorations, yet little is known about these enzyme families especially with regard to their diversity in activity. Bacteroidetes bacteria are dominant members of the microbiota and often encode their carbohydrate-active enzymes in multigene polysaccharide utilization loci (PULs). Here we present the characterization of three CEs found in a PUL encoded by the gut Bacteroidete Dysgonomonas mossii. We demonstrate that the CEs are functionally distinct, with one highly efficient CE6 acetyl esterase and two CE1 enzymes with feruloyl esterase activities. One multidomain CE1 enzyme contains two CE1 domains: an N-terminal domain feruloyl esterase, and a C-terminal domain with minimal activity on model substrates. We present the structure of the C-terminal CE1 domain with the carbohydrate-binding module that bridges the two CE1 domains, as well as a complex of the same protein fragment with methyl ferulate. The investment of D. mossii in producing multiple CEs suggests that improved accessibility of xylan for GHs and cleavage of covalent polysaccharide-polysaccharide and lignin-polysaccharide bonds are important enzyme activities in the gut environment

Biomechanical Characterisation of Bone-anchored Implant Systems for Amputation Limb Prostheses: A Systematic Review

Bone-anchored limb prostheses allow for the direct transfer of external loads from the prosthesis to the skeleton, eliminating the need for a socket and the associated problems of poor fit, discomfort, and limited range of movement. A percutaneous implant system for direct skeletal attachment of an external limb must provide a long-term, mechanically stable interface to the bone, along with an infection barrier to the external environment. In addition, the mechanical integrity of the implant system and bone must be preserved despite constant stresses induced by the limb prosthesis. Three different percutaneous implant systems for direct skeletal attachment of external limb prostheses are currently clinically available and a few others are under investigation in human subjects. These systems employ different strategies and have undergone design changes with a view to fulfilling the aforementioned requirements. This review summarises such strategies and design changes, providing an overview of the biomechanical characteristics of current percutaneous implant systems for direct skeletal attachment of amputation limb prostheses

Theoretical Aspects of Particle Production

These lectures describe some of the latest data on particle production in high-energy collisions and compare them with theoretical calculations and models based on QCD. The main topics covered are: fragmentation functions and factorization, small-x fragmentation, hadronization models, differences between quark and gluon fragmentation, current and target fragmentation in deep inelastic scattering, and heavy quark fragmentation.Comment: 26 pages, 27 figures. Lectures at International Summer School on Particle Production Spanning MeV and TeV Energies, Nijmegen, The Netherlands, August 199

Escherichia coli induces apoptosis and proliferation of mammary cells

Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection, The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1 beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection, Induction of matrix metalloproteinase-g, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue, These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation