Pre-operative Planning and Intra-operative Guidance for Shoulder Replacement Surgery

Shoulder joint replacement, or arthroplasty, is indicated in cases where arthritis or trauma has resulted in severe joint damage that in turn causes increased pain and decreased function. However, shoulder arthroplasty is less successful than hip and knee replacement, mostly due to the complexity of the shoulder joint and the resultant complexity of the replacement operation. In this paper we present a complete visualization-oriented pre-operative planning and intra-operative guidance approach for shoulder joint replacement. Our system assists the surgeon by allowing a virtual arthroplasty procedure whilst giving feedback, primarily via patient- and procedure-specific joint range of motion (ROM) simulation and visualization. After a successful planning, our system automatically generates a 3D model of a patient-specific mechanical guidance device that is then produced by a rapid prototyping machine and can be used during the operation. In this way, a computer-based guidance system is not required in the operating room

Franchising:essence and accounting prosedure

У статті досліджено теоретичні аспекти франчайзингових операцій, визначено переваги і недоліки для учасників договору франчайзингу. Проаналізовано підходи науковців до методики відображення франчайзингу в обліку.This paper investigates the theoretical aspects of franchise operations, advantages and disadvantages for participants of the franchising agreement. Analysis of scientific approaches to accounting procedure of franchising is give

Could 'nerves of steel' guide sensory signals?

This article makes assumptions of the consequences of having coaxial steel cables for nerves. It is found that if a person would have coaxial steel cables instead of axons, the body would have to find a way to impose an initial potential of about 90 mV onto the beginning of this axon since the signal is now passed on passively instead of actively. This signal is however not seriously damped within the cable. This nerve would however be able to handle impulses of a higher frequency at a higher speed, allowing one to have a higher maximally ‘feelable’ intensity of sensations

What would be the effect of having ‘nerves of steel’ on the ability to bend your elbow?

This article makes assumptions of the consequences of having coaxial steel cables for nerves. Where regular nerves are very flexible, for coaxial cables this is not necessarily the case since it is steel that has to be bent. It is found through calculations on the required momentum, taking the yield stress of steel into account, that having coaxial steel cables for nerves adds about 45 nN per axon through the elbow to the force required to lift the lower arm. Through calculations in two ways on the number of nerves that go through the lower arm, it is found that this number is around 2.4x107 so that the total additional force required to lift the lower arm is about 1.1 N

What if from now on, we start shooting all waste produced worldwide into space?

This article explores the difficulties and the consequences of shooting all waste produced on Earth into space. It is found that if we do not want the waste to orbit Earth, the energy required to shoot one years’ worth of garbage into space would be one third of the total yearly energy consumption of humanity. If it is brought into orbit instead, in 50 years it will be massive enough to have a gravitational field strong enough to let people walk around on it as long as they do not go faster than 8 kmh-1

What is the smallest planet where an astronaut could accidentally escape gravity?

In this article, it is evaluated what the required dimensions of a small object in space (such as a small planet, a moon or an asteroid) should be in order to have a gravitational pull that is just strong enough to not let humans escape it by running and jumping. By evaluating the escape velocity, it is found that a mass-to-radius ratio of 5.8x1010 kgm-1 will prevent regular astronauts from escaping, and a ratio of 1.15x1012 kg m-1 will prevent even the fastest human alive from escaping the gravitational pull. Objects in our solar system that are near these ratios are Leda, 433 Eros and S/2003 (130) 1

Effect of rotator cuff dysfunction on the initial mechanical stability of cementless glenoid components

The functional outcome of shoulder replacement is related to the condition of the rotator cuff. Rotator cuff disease is a common problem in candidates for total shoulder arthroplasty; this study relates the functional status of the rotator cuff to the initial stability of a cementless glenoid implant. A 3D finite element model of a complete scapula was used to quantify the effect of a dysfunctional rotator cuff in terms of bone-implant interface micromotions when the implant is physiologically loaded shortly after surgery. Four rotator cuff conditions (from fully intact to progressively ruptured rotator cuff tendons) as well as two bone qualities were simulated in a model. Micromotions were significantly larger in the worst modeled cuff dysfunction (i.e. the supraspinatus and infraspinatus tendons were fully dysfunctional). Micromotions were also significantly different between conditions with healthy and poor bone quality. The implant's initial stability was hardly influenced by a dysfunctional supraspinatus alone. However, when the infraspinatus was also affected, the glenohumeral joint force was displaced to the component's rim resulting in larger micromotions and instability of the implant

Individual human serum differs in the amount of antibodies with affinity for pig fetal ventral mesencephalic cells and the ability to lyse these cells by complement activation

Xenografting pig fetal ventral mesencephalic (pfVM) cells to repair the dopamine deficit in patients with Parkinson's disease is the focus of both experimental and clinical investigations. Although there have been marked advances in the experimental and even clinical application of these xenogeneic transplantations, questions regarding the host's xenospecific immune response remain unanswered. It has been shown that human serum is able to lyse pfVM tissue by both anti-gal-gal and non-anti-gal-gal antibodies by complement activation. The aim of this study was to investigate whether interindividual differences exist in the levels of pfVM cell-specific IgM and IgG subclass antibodies, their ability to lyse pfVM cells in vitro and the relationship between both. Pig fetal VM cells were incubated with heat-inactivated serum from 10 different individuals and binding of IgM antibodies and IgG subclass antibodies to pfVM cells was analyzed by flow cytometry. The ability to lyse pfVM cells was analyzed exposing Cr-51-labeled pfVM cells to fresh serum or isolated IgM and IgG from the same individuals and subsequent determination of released Cr-51 from lysed cells. Strong differences were found between individuals in the levels of pfVM cell-specific IgM antibodies: antibody levels differed up to 40-fold. pfVM-specific IgG1 and IgG2 levels were only detectable in a few individuals. The ability to lyse pfVM cells ranged from negligible lysis up to 66.5% specific lysis. There was a strong correlation between the levels of individual pfVM-specific IgM antibodies and the ability to lyse pfVM cells in vitro. Isolated IgM, but not IgG, was able to lyse pfVM cells in the presence of complement. In conclusion, the interindividual differences in the levels of IgM with affinity for pfVM cells and their ability to lyse pfVM cells in vitro are considerable. Only few individuals possessed IgG1 and IgG2 subclass antibodies with affinity for pfVM. These findings may influence patient selection for porcine transplants and chances of graft survival in individual patients

Huntingtin gene repeat size variations affect risk of lifetime depression

Huntington disease (HD) is a severe neuropsychiatric disorder caused by a cytosine-adenine-guanine (CAG) repeat expansion in the HTT gene. Although HD is frequently complicated by depression, it is still unknown to what extent common HTT CAG repeat size variations in the normal range could affect depression risk in the general population. Using binary logistic regression, we assessed the association between HTT CAG repeat size and depression risk in two well-characterized Dutch cohorts─the Netherlands Study of Depression and Anxiety and the Netherlands Study of Depression in Older Persons─including 2165 depressed and 1058 non-depressed persons. In both cohorts, separately as well as combined, there was a significant non-linear association between the risk of lifetime depression and HTT CAG repeat size in which both relatively short and relatively large alleles were associated with an increased risk of depression (β = −0.292 and β = 0.006 for the linear and the quadratic term, respectively; both P < 0.01 after adjustment for the effects of sex, age, and education level). The odds of lifetime depression were lowest in persons with a HTT CAG repeat size of 21 (odds ratio: 0.71, 95% confidence interval: 0.52 to 0.98) compared to the average odds in the total cohort. In conclusion, lifetime depression risk was higher with both relatively short and relatively large HTT CAG repeat sizes in the normal range. Our study provides important proof-of-principle that repeat polymorphisms can act as hitherto unappreciated but complex genetic modifiers of depression

Chronic transplant dysfunction and transplant arteriosclerosis:New insights into underlying mechanisms

Although effective in the short-term, clinical solid-organ transplantation has not achieved its goals as a long-term treatment for patients with end-stage organ failure. Development of so-called chronic transplant dysfunction (CTD) is now recognised as the predominant cause of allograft loss long-term (after the first post-operative year) following transplantation. CTD has the remarkable histological feature that the luminal areas of intragraft arteries become obliterated, predominantly with vascular smooth muscle cells intermingled with some inflammatory cells. The development of this transplant vasculopathy, referred to as transplant arteriosclerosis (TA), is a multifactorial process and many risk factors have been identified. However, the precise pathogenetic mechanisms leading to TA are largely unknown and, as a result, current prevention and treatment protocols are inadequate. This review discusses the risk factors for TA and current views on the pathogenetic mechanisms leading to this vasculopathy. We argue here that host-derived cells contribute to the development of these vascular lesions, and propose that TA results from a normal vascular repair process that proceeds beyond the needs of functional repair. Guided by the proposed sequence of events, we finally discuss possible directions for future intervention strategies to prevent TA after solid-organ transplantation.</p