Sterile acellular dermal collagen as a treatment for rippling deformity of breast.

Prosthetic implants are frequently used for breast augmentation and breast reconstruction following mastectomy. Unfortunately, long-term aesthetic results of prosthetic breast restoration may be hindered by complications such as rippling, capsular contracture, and implant malposition. The advent of use of acellular dermal matrices has greatly improved the outcomes of prosthetic breast reconstruction. We describe a case of rippling deformity of breast that was treated using an acellular dermal matrix product, AlloMax. The patient presented with visible rippling of bilateral prosthetic breast implants as well as significant asymmetry of the breasts after multiple excisional biopsies for right breast ductal carcinoma in situ. A 6 × 10 cm piece of AlloMax was placed on the medial aspect of each breast between the implant and the skin flap. Follow-up was performed at 1 week, 3 months, and 1 year following the procedure. The patient recovered well from the surgery and there were no complications. At her first postoperative follow-up the patient was extremely satisfied with the result. At her 3-month and 1-year follow-up she had no recurrence of her previous deformity and no new deformity

Extending fatigue life of aircraft fuselage structures using laser-peening

Fatigue of airframe structures is a constant challenge to aircraft manufacturers when designing, maintaining and repairing new and aging metallic components. Laser-Peening (LP) is a highly flexible and controllable surface treatment and relatively new to manufacturers of large civil aircraft which demonstrated that it can extend the fatigue and crack growth life in aluminium alloys by introducing deep compressive Residual Stresses (RS). Currently there is no application of LP to any components of large civil aircraft. The aim of this research was to demonstrate and explore different LP strategies that can produce significant extension of the fatigue and crack growth performance of aircraft fuselage structures using Laser-Peening. Two representative samples made from 2000 series aluminium alloy were designed to represent features of the fuselage: A Centre Cracked Tension (CCT) panel made of 1.6 mm thick 2524-T3 represented the fuselage skin. Single overlap Lap-Joints (LJ) of 2.5 mm thick 2024-T3 aluminium with titanium Hi-Lok bolts arrayed in 5 columns and 3 rows embodied longitudinal LJ of aircraft fuselages. Both test samples were laser-peened without protective coating (LPwC) using a range of LP strategies in which LP process parameters and spatial arrangements of laser-peened areas were systematically varied. RS fields were measured before fatigue testing under constant amplitude loading. RS measurements used Incremental Centre Hole Drilling (ICHD) and X-ray and Neutron diffraction techniques. Laser-peening produced peak compressive RS of 200 – 350 MPa and compression stress penetration depths between 700-1000 μm. These values are superior to RS profiles induced by Shot-Peening. The value of peak compression stress and penetration depth depends on LP process parameters and on the LP layout. The latter defines the location and size of the laser-peened areas. A study of the effect of different LP strategies to establish the most effective LP treatment to enhance crack growth life of fuselage skins was performed using a Finite Element based crack growth model. The model was first used to introduce balanced RS fields into a cracked CCT sample. The effective stress intensity factor range (ΔKeff) and effective R-ratios (Reff) were then calculated as the crack tip progressed through the sample. Subsequently, fatigue crack growth rates and lives were computed using Walker’s empirical crack growth law. The accuracy of the model was demonstrated by comparison with crack growth test results from laser-peened CCT-samples. Results of the parameter study showed that an increase in the level of compression within the LPS increased life most significantly. Increased width of peen stripe increased the life while increasing the distance of the stripe from the starting position of the crack tip decreased the life. Four different LP strategies were applied to LJ samples. Subsequent fatigue testing demonstrated fatigue life improvements of between 1.14 to 3.54, depending on the LP strategy. The LP layout was identified as a key parameter determining the fatigue life. It was found that when small LP areas were used, to leave as much elastic material as possible between the peened areas, larger compressive stresses and minimised balancing tensile stresses were produced. Observations of fatigue fractures on joint samples showed that crack initiation occurred remote from the fastener holes, either in regions of fretting fatigue in peened areas or in regions of balancing tensile stress adjacent to peen boundaries. Optimum fatigue lives occurred when both fracture types occurred in the same sample. Striation spacing measurement and analysis showed that compressive residual stresses had little or no effect on fatigue growth rates at crack lengths < 600 µm. The majority of fatigue life extension was achieved during initiation and crack growth < 600 μm. The obtained results established evidence of how aircraft fuselage structures made of conventional 2000 series aluminium-copper alloys can be effectively laser-peened to produced fatigue life improvements and also of how to avoid any detrimental reductions in fatigue life which can also occur when LP is applied randomly. The generated research conclusions are applicable to other metals, geometries and components

Functional characterisation of interferon stimulated genes in respiratory viral infection

A key element of host antiviral defence is cell intrinsic immunity, driven by an array of interferon stimulated genes (ISGs), few of which have been properly characterised. However, the breadth of ISG antiviral mechanisms suggests this gene network can target nearly every stage of a viral life cycle. Respiratory syncytial virus (RSV) is responsible for a vast number of infections, primarily in infants. Intriguingly, most infants requiring hospitalisation with a severe RSV infection present with no known risk factor. It was hypothesised that ISGs induced by RSV infection represent potential genetic risk factors that could influence virus control and disease severity between individuals. The IFN-induced transmembrane (IFITM) family of ISGs are broadly antiviral and thought to target virus entry. The data presented here expand our understanding of IFITM1 function by demonstrating that antiviral activity is dependent upon plasma membrane localisation. The in vivo relevance of IFITM1 was also probed in a monogenic knockout mouse model, for the first time demonstrating that the loss of IFITM1 alone is sufficient to result in a loss of viral control and enhanced disease severity. Next, the role of IFN-induced protein 44 (IFI44) proteins was explored as these ISGs are especially poorly characterised and are highly induced by RSV infection. There are conflicting data on the antiviral activity of IFI44 and IFI44L during RSV infection. This study presents evidence that these genes are antiviral, impacting an early point of the viral life cycle associated with reduced polymerase activity. Finally, the loss of IFI44 in vivo was shown to result in increased RSV disease severity.Open Acces

The wider determinants of inequalities in health: a decomposition analysis

<p>Abstract</p> <p>Background</p> <p>The common starting point of many studies scrutinizing the factors underlying health inequalities is that material, cultural-behavioural, and psycho-social factors affect the distribution of health systematically through income, education, occupation, wealth or similar indicators of socioeconomic structure. However, little is known regarding if and to what extent these factors can assert systematic influence on the distribution of health of a population independent of the effects channelled through income, education, or wealth.</p> <p>Methods</p> <p>Using representative data from the German Socioeconomic Panel, we apply Fields' regression based decomposition techniques to decompose variations in health into its sources. Controlling for income, education, occupation, and wealth, we assess the relative importance of the explanatory factors over and above their effect on the variation in health channelled through the commonly applied measures of socioeconomic status.</p> <p>Results</p> <p>The analysis suggests that three main factors persistently contribute to variance in health: the capability score, cultural-behavioural variables and to a lower extent, the materialist approach. Of the three, the capability score illustrates the explanatory power of interaction and compound effects as it captures the individual's socioeconomic, social, and psychological resources in relation to his/her exposure to life challenges.</p> <p>Conclusion</p> <p>Models that take a reductionist perspective and do not allow for the possibility that health inequalities are generated by factors over and above their effect on the variation in health channelled through one of the socioeconomic measures are underspecified and may fail to capture the determinants of health inequalities.</p

The Spatio-Temporal Structure of Spiral-Defect Chaos

We present a study of the recently discovered spatially-extended chaotic state known as spiral-defect chaos, which occurs in low-Prandtl-number, large-aspect-ratio Rayleigh-Benard convection. We employ the modulus squared of the space-time Fourier transform of time series of two-dimensional shadowgraph images to construct the structure factor ${S}({\vec k},\omega )$. This analysis is used to characterize the average spatial and temporal scales of the chaotic state. We find that the correlation length and time can be described by power-law dependences on the reduced Rayleigh number ${\epsilon}$. These power laws have as yet no theoretical explanation.Comment: RevTex 38 pages with 13 figures. Due to their large size, some figures are stored as separate gif images. The paper with included hi-res eps figures (981kb compressed, 3.5Mb uncompressed) is available at ftp://mobydick.physics.utoronto.ca/pub/MBCA96.tar.gz An mpeg movie and samples of data are also available at ftp://mobydick.physics.utoronto.ca/pub/. Paper submitted to Physica

Treatment of elbow osteomyelitis with an interposition arthroplasty using a rectus abdominis free flap.

Osteomyelitis of the elbow may be a complex clinical problem. Treatment goals include the eradication of infection and preservation of maximal joint function. Bony debridement may be necessary in addition to elbow joint arthroplasty. The use of synthetic material or allograft as the arthroplasty material may be contraindicated in the setting of infection. The use of free muscle transfer as an arthroplasty medium has not been well described.A 22-year-old paraplegic man developed recurrent osteomyelitis of the right elbow, necessitating extensive bony debridement by the orthopedic surgery team. Reconstruction arthroplasty was performed using a free rectus abdominis muscle flap as the arthroplasty material to serve as a source of biologically active, well-vascularized arthroplasty medium in the presence of ongoing infection.A successful free muscle flap arthroplasty was performed. External fixation and physical therapy were implemented postoperatively. The patient had resolution of osteomyelitis and excellent functional use of the elbow for activities of daily living and wheelchair motion.Elbow arthroplasty in the setting of active infection may be accomplished by means of free tissue muscle transfer. Elimination of infection and acceptable joint function may be possible with this form of reconstruction

REACTION MECHANISMS AND RATE LIMITATIONS IN DRY ETCHING OF SILICON DIOXIDE VITH ANHYDROUS HYDROGEN FLUORIDE

A novel dry etching process for silicon dioxide has been developed. This process, carried out at ambient temperature and pressure, uses anhydrous hydrogen fluoride, water vapor in a nitrogen carrier, and a unique processing sequence to achieve etch rates of about 200A/second, with 5 percent or better uniformity. The overall reaction is a complicated sequence of surface hydration and surface fluorlnation by adsorption, reaction, and product desorptlon. This paper presents two proposed reaction mechanisms and describes how experimental data from a laminar flow reactor were used to evaluate the mechanisms

Determinants of hospital costs and performance variation : Methods, models and variables for the EuroDRG project

Empirical studies of variation in hospital costs fall into two camps: those based on analysis of the costs of individual patients and those – the vast majority – that analyse costs reported at the hospital level. In this review, we consider how patient-level and hospital-level data are related and outline approaches to analyzing them. The second part of the review considers general specification choices and methods of efficiency analysis. Moreover, we specify a model to be used in the empirical analyses of the EuroDRG project

The Effects of Adipose-Derived Stem Cells Differentiated Into Endothelial Cells and Osteoblasts on Healing of Critical Size Calvarial Defects.

Delayed vascularization and resultant resorption limits the clinical use of tissue engineered bony constructs. The objective of this study is to develop a strategy to accelerate the neovascularization of tissue-engineered bony constructs using endothelial differentiated adipose-derived stem cells (ASC). The authors harvested ASC from inguinal fat pads of male Lewis rats (n = 5) and induced toward endothelial and osteoblastic lineages. The authors created critical size calvarial defects on male Lewis rats (n = 30) and randomized the animals into 4 groups. For the repair of the defects the authors used hydroxyapatite/poly(lactide-co-glycolide) [HA-PLG] scaffolds in group I, HA-PLG scaffolds seeded with ASC in group II, HA-PLG scaffolds seeded with ASC-derived endothelial cells in group III, and HA-PLG scaffolds seeded with ASC-derived osteoblasts in group IV. The authors evaluated the bone healing histologically and with micro-computed tomography (CT) scans 8 weeks later. Adipose-derived stem cells exhibited the characteristics of endothelial and osteogenic lineages, and attached on HA-PLG scaffolds after differentiation. Micro-CT analysis revealed that highest bone mineral density was in group IV (1.46 ± 0.01 g/cm) followed by groups III (1.43 ± 0.05 g/cm), I (1.42 ± 0.05 g/cm), and II (1.3 ± 0.1 g/cm). Hematoxylin-Eosin and Masson Trichrome staining revealed similar results with the highest bone regeneration in group IV followed by groups II, III, and I. Regenerated bone in group IV also had the highest vascular density, but none of these differences achieved statistical significance (P &gt; 0.05). The ASC-derived endothelial cells and osteoblasts provide a limited increase in calvarial bone healing when combined with HA-PLG scaffolds

Spiral Defect Chaos in Large Aspect Ratio Rayleigh-Benard Convection

We report experiments on convection patterns in a cylindrical cell with a large aspect ratio. The fluid had a Prandtl number of approximately 1. We observed a chaotic pattern consisting of many rotating spirals and other defects in the parameter range where theory predicts that steady straight rolls should be stable. The correlation length of the pattern decreased rapidly with increasing control parameter so that the size of a correlated area became much smaller than the area of the cell. This suggests that the chaotic behavior is intrinsic to large aspect ratio geometries.Comment: Preprint of experimental paper submitted to Phys. Rev. Lett. May 12 1993. Text is preceeded by many TeX macros. Figures 1 and 2 are rather lon