970 research outputs found
Quality of Life Before and After Cosmetic Surgery: Should Body Dysmorphic Disorder Be Considered an Absolute or Relative Contraindication for Cosmetic Surgery?
Body Dysmorphic Disorder (BDD) has historically been regarded as a strong contraindication for cosmetic plastic surgery. New research now suggests that the contraindications to cosmetic surgery in patients with BDD may not be so absolute. This paper reviews diagnostic criteria, diagnostic challenges, and current standard of treatment of BDD. It then presents the idea of insight analysis in the BDD patient as a significant factor in determining if patients with BDD may or may not benefit from cosmetic surgery or procedures
Bid distributions of competing agents in simple models of auctions
Models of auctions or tendering processes are introduced. In every round of bidding the players select their bid from a probability distribution and whenever a bid is unsuccessful, it is discarded and replaced. For simple models, the probability distributions evolve to a stationary power law with the exponent dependent only on the number of players. For most situations, the system converges towards a state where all players are identical. A number of variations of this model are introduced and the application of these models to the dynamics of market makers is discussed. The effect of price uncertainty on bid distributions is presented. An underlying market structure generates heterogenous agents which do not have power law bid distribution in general
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Systemic and Intra-Habenular Activation of the Orphan G Protein-Coupled Receptor GPR139 Decreases Compulsive-Like Alcohol Drinking and Hyperalgesia in Alcohol-Dependent Rats.
GPR139 is an orphan G protein-coupled receptor (GPCR) that is expressed mainly in the brain, with the highest expression in the medial habenula. The modulation of GPR139 receptor function has been hypothesized to be beneficial in the treatment of some mental disorders, but behavioral studies have not yet provided causal evidence of the role of GPR139 in brain dysfunction. Because of the high expression of GPR139 in the habenula, a critical brain region in addiction, we hypothesized that GPR139 may play role in alcohol dependence. Thus, we tested the effect of GPR139 receptor activation using the selective, brain-penetrant receptor agonist JNJ-63533054 on addiction-like behaviors in alcohol-dependent male rats. Systemic administration of JNJ-63533054 (30 mg/kg but not 10 mg/kg, p.o.) reversed the escalation of alcohol self-administration in alcohol-dependent rats, without affecting water or saccharin intake in dependent rats or alcohol intake in nondependent rats. Moreover, systemic JNJ-63533054 administration decreased withdrawal-induced hyperalgesia, without affecting somatic signs of alcohol withdrawal. Further analysis demonstrated that JNJ-63533054 was effective only in a subgroup of dependent rats that exhibited compulsive-like alcohol drinking. Finally, site-specific microinjection of JNJ-63533054 in the habenula but not interpeduncular nucleus (IPN) reduced both alcohol self-administration and withdrawal-induced hyperalgesia in dependent rats. These results provide robust preclinical evidence that GPR139 receptor activation reverses key addiction-like behaviors in dependent animals, suggest that GPR139 may be a novel target for the treatment of alcohol use disorder, and demonstrate that GPR139 is functionally relevant in regulating mammalian behavior
Consumption-Based Conservation Targeting: Linking Biodiversity Loss to Upstream Demand through a Global Wildlife Footprint.
Although most conservation efforts address the direct, local causes of biodiversity loss, effective long-term conservation will require complementary efforts to reduce the upstream economic pressures, such as demands for food and forest products, which ultimately drive these downstream losses. Here, we present a wildlife footprint analysis that links global losses of wild birds to consumer purchases across 57 economic sectors in 129 regions. The United States, India, China, and Brazil have the largest regional wildlife footprints, while per-person footprints are highest in Mongolia, Australia, Botswana, and the United Arab Emirates. A US$100 purchase of bovine meat or rice products occupies approximately 0.1 km2 of wild bird ranges, displacing 1-2 individual birds, for 1 year. Globally significant importer regions, including Japan, the United Kingdom, Germany, Italy, and France, have large footprints that drive wildlife losses elsewhere in the world and represent important targets for consumption-focused conservation attention
DNA and Depletant Based Control of the Collective Motion of Gliding Microtubules
Motor proteins, like kinesin, transport cargo within biological cells by transforming chemical energy into mechanical energy through the hydrolysis of adenosine triphosphate (ATP). Kinesins walk across small tracks called microtubules. Recent studies have found that these concepts can be applied in vitro by attaching the motors to a glass substrate, on which microtubules can then glide across. These systems could be useful for many applications, such as targeted drug delivery and efficient, easy medical diagnosis. However, the motion of traveling microtubules is randomly ordered, and methods for controlling it are often hard to implement and recreate. One promising approach is to use depletants, or unreactive macromolecules, that can align microtubules in the same direction by forcing them to move together. This study aims to improve control of microtubule collective motion by using DNA as a signal to increase the effect that depletants have on the microtubule system. This is done by attaching bulky DNA molecules to the filaments, thus increasing their volumes. By comparing the organization of the system before and after the modification of the microtubules, the effects can be analyzed at many concentrations. This study provides an assessment of the relationship between the use of altered microtubules and the concentration of depletants within a gliding assay to induce an ordered collective motion
Numerical and experimental studies on the mechanical behaviour of the distal femur following total knee arthroplasty
The history of total knee arthroplasty stretches back over 70 years. Many studies
have shown that TKA is, in general, a successful operation for the relief of joint pain,
with patient satisfaction rates of 90-95% and implant survival rates at 10-15 years of
greater than 90%. However, a number of studies have also shown the potential for
failures or complications arising post-implantation leading to revision surgery.
This thesis presents finite element (FE) models of the distal femur following primary
and revision total knee arthroplasty. Pre-arthroplasty models are also developed for
comparison. Particular attention is given to how femoral component design and
method of fixation impacts the mechanical environment of the distal femur and
stability of the prosthesis. FE analyses with fully bonded interfaces indicate that
femoral components are subject to areas of low stress (stress shielding) immediately
under the anterior flange and chamfer regardless of internal implant features.
However, internal implant features were found to play a role in the pattern and
magnitude of stress concentrations. Both stresses and motions were observed to
increase with increasing flexion angle, indicating the importance of testing at
multiple angles.
The initial models of the distal femur were extended to incorporate the effects of
ageing and endosteal thinning of the femoral cortex, through novel application of
pre-existing FE modelling techniques, specifically the ability to assign variable
material properties corresponding to the nodal temperatures output from a heat
transfer analysis. The findings from this study indicate that older patients with
osteoporosis may be at increased risk of periprosthetic fracture compared to younger
healthy patients. The use of a revision femoral component with a cemented stem as a
means to mitigate this fracture risk was also investigated.
FE analyses using frictional interfaces were employed to determine the influence of
femoral component design on micromotion at the interface. These models showed
that all primary implants were subject to similar magnitudes of relative motion at the
interface, however, the distinct internal implant features led to very different regional
variations. Furthermore, certain internal implant features (i.e. femoral box) were
found to be highly sensitive to errors in surgical bone cuts. This aspect of the thesis
also concluded that the addition of a stem served to significantly reduce motions at
the interface in comparison to primary stemless implants. Long stemmed prostheses
were found to result in the smallest levels of interface motion.
This study also detailed the design and creation of an in vitro test setup for the
purposes of determining the influence of stem length and fixation on the stability of
revision prostheses. Experimental results using this test rig showed that a cemented
short stem provides as much initial stability as the uncemented long stem, and is
easier to fit surgically. Corresponding FE models incorporating a virtual
representation of the test rig and in vitro loading conditions revealed that the relative
motion at the multi-planar bone-prosthesis interface cannot be adequately described
using a single reference point. However, in vitro setups may be used to predict a
general measure of implant stability and to provide a source of calibration for FE.
The distal femur models were further modified to investigate how the presence of
condylar defects as classified by AORI defect classification system (Engh 2006) and
weak osseous support due to osteoporosis may adversely affect the survival of the
prosthesis. These investigations revealed that fixation of the femoral component, the
presence of a large condylar defect and the level of osseous support all had an impact
on stress in the implant, it is concluded that a non-modular approach should be
adopted in older patient groups with severe osteoporosis to mitigate the risk of
component junction failure and distal femoral fracture
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