Material Strength Effect in the Shock Compression of Alumina

The Hugoniot elastic limits (HEL) of a high-density aluminum oxide ceramic (Lucalox) and a slightly lower-density ceramic (porosity approximately 4%) were determined to be 112±13 and 83±5 kbar, respectively. Above the HEL, the shock-stress-volume Hugoniot curves for both materials are offset by 40 kbar or more above their hydrostatic-pressure-volume curves. These results indicate that shear stresses with magnitudes of about 30–40 kbar persist in aluminum oxide to shock-pressure levels of at least 300 kbar

Relaxation rates and collision integrals for Bose-Einstein condensates

Near equilibrium, the rate of relaxation to equilibrium and the transport properties of excitations (bogolons) in a dilute Bose-Einstein condensate (BEC) are determined by three collision integrals, $\mathcal{G}^{12}$, $\mathcal{G}^{22}$, and $\mathcal{G}^{31}$. All three collision integrals conserve momentum and energy during bogolon collisions, but only $\mathcal{G}^{22}$ conserves bogolon number. Previous works have considered the contribution of only two collision integrals, $\mathcal{G}^{22}$ and $\mathcal{G}^{12}$. In this work, we show that the third collision integral $\mathcal{G}^{31}$ makes a significant contribution to the bogolon number relaxation rate and needs to be retained when computing relaxation properties of the BEC. We provide values of relaxation rates in a form that can be applied to a variety of dilute Bose-Einstein condensates.Comment: 18 pages, 4 figures, accepted by Journal of Low Temperature Physics 7/201

Medicare Payments for Common Inpatient Procedures: Implications for Episode-Based Payment Bundling

Aiming to align provider incentives toward improving quality and efficiency, the Center for Medicare and Medicaid Services is considering broader bundling of hospital and physician payments around episodes of inpatient surgery. Decisions about bundled payments would benefit from better information about how payments are currently distributed among providers of different perioperative services and how payments vary across hospitals.Using the national Medicare database, we identified patients undergoing one of four inpatient procedures in 2005 (coronary artery bypass [CABG], hip fracture repair, back surgery, and colectomy). For each procedure, price-standardized Medicare payments from the date of admission for the index procedure to 30 days postdischarge were assessed and categorized by payment type (hospital, physician, and postacute care) and subtype.Average total payments for inpatient surgery episodes varied from U.S.$26,515 for back surgery to U.S.$45,358 for CABG. Hospital payments accounted for the largest share of total payments (60–80 percent, depending on procedure), followed by physician payments (13–19 percent) and postacute care (7–27 percent). Overall episode payments for hospitals in the lowest and highest payment quartiles differed by U.S.$16,668 for CABG, U.S.$18,762 for back surgery, U.S.$10,615 for hip fracture repair, and U.S.$12,988 for colectomy. Payments to hospitals accounted for the largest share of variation in payments. Among specific types of payments, those associated with 30-day readmissions and postacute care varied most substantially across hospitals.Fully bundled payments for inpatient surgical episodes would need to be dispersed among many different types of providers. Hospital payments—both overall and for specific services—vary considerably and might be reduced by incentives for hospitals and physicians to improve quality and efficiency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79298/1/j.1475-6773.2010.01150.x.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/79298/2/HESR_1150_sm_authormatrix.pd

Fluoxetine effects assessment on the life cycle of aquatic invertebrates

International audienceFluoxetine is a serotonin re-uptake inhibitor, generally used as an antidepressant. It is suspected to provoke substantial effects in the aquatic environment. This study reports the effects of fluoxetine on the life cycle of four invertebrate species, Daphnia magna, Hyalella azteca and the snail Potamopyrgus antipodarum exposed to fluoxetine spiked-water and the midge Chironomus riparius exposed to fluoxetine-spiked sediments. For D. magna, a multi-generational study was performed with exposition of newborns from exposed organisms. Effects of fluoxetine could be found at low measured concentrations (around 10 micro g l(-1)), especially for parthenogenetic reproduction of D. magna and P. antipodarum. For daphnids, newborns length was impacted by fluoxetine and the second generation of exposed individuals showed much more pronounced effects than the first one, with a NOEC of 8.9 micro g l(-1). For P. antipodarum, significant decrease of reproduction was found for concentrations around 10 micro g l(-1). In contrast, we found no effect on the reproduction of H. azteca but a significant effect on growth, which resulted in a NOEC of 33 micro g l(-1), expressed in nominal concentration. No effect on C. riparius could be found for measured concentrations up to 59.5 mg kg(-1). General mechanistic energy-based models showed poor relevance for data analysis, which suggests that fluoxetine targets specific mechanisms of reproduction

Thermodynamic aspects of the grain boundary segregation in Cu (Bi) alloys

AbstractÐThe grain boundary segregation of Bi in dilute polycrystalline Cu±Bi alloys was systematically studied as a function of temperature and composition. The temperature dependencies of the Gibbsian excess of Bi at the grain boundaries exhibited discontinuous changes at the temperatures close to, but dierent from the bulk solidus temperatures. The observed segregational phase transition was interpreted in terms of prewetting model.

In vivo examination of healthy human skin after short-time treatment with moisturizers using confocal Raman spectroscopy and optical coherence tomography: Preliminary observations

Skin is our barrier against environmental damage. Moisturizers are widely used to increase hydration and barrier integrity of the skin; however, there are contrasting observations on their in vivo effects in real-life settings. In cosmetic studies, cor- neometers and tewameters are traditionally used to assess skin hydration. In this study, two novel noninvasive diagnostic techniques, optical coherence tomography (OCT) and confocal Raman spectroscopy, were used to analyze stratum corneum and epidermal thickness (ET), water content, blood flow in function of depth, skin roughness, attenuation coefficient, natural moisturizing factor, ceramides and free fatty acids, cholesterol, urea, and lactates in 20 female subjects aged between 30 and 45 before and after 2 weeks application of a commercially available mois- turizing lotion on one forearm. The untreated forearm served as control. A third measurement was conducted 1 week after cessation of moisturizing to verify whether the changes in the analyzed parameters persisted. We noticed a reduction in skin roughness, an increase in ceramides and free fatty acids and a not statistically sig- nificant increase in ET. As a conclusion, short time moisturizing appears insufficient to provide significant changes in skin morphology and composition, as assessed by OCT and RS. Novel noninvasive imaging methods are suitable for the evalu- ation of skin response to topical moisturizers. Further studies on larger sample size and longer treatment schedules are needed to analyze changes under treat- ment with moisturizers and to standardize the use of novel noninvasive diagnostic techniques

Line-field optical coherence tomography: in\ua0vivo diagnosis of basal cell carcinoma subtypes compared with histopathology

Background: Basal cell carcinoma (BCC) is the most common skin cancer in the general population. Treatments vary from Mohs surgery to topical therapy, depending on the subtype. Dermoscopy, reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) have gained a foothold in daily clinical practice to optimize diagnosis and subtype-oriented treatment. The new technique of line-field confocal OCT (LC-OCT) allows imaging at high resolution and depth, but its use has not yet been investigated in larger studies. Aim: To evaluate the main LC-OCT criteria for the diagnosis and subtyping of BCC compared with histopathology, OCT and RCM. Methods: In total, 52 histopathologically confirmed BCCs were evaluated for imaging criteria. Their frequency, predictive values and ROC curves were calculated. A multinominal regression with stepwise variables selection to distinguish BCC subtypes was performed. Results: Nodular BCCs were mainly characterized by atypical keratinocytes, altered dermoepidermal junction (DEJ), tumour nests in the dermis, dark clefting, prominent vascularization and white hyper-reflective stroma. Superficial BCCs showed a thickening of the epidermis due to a series of tumour lobules with clear connection to the DEJ (string of pearls pattern). Infiltrative BCCs were characterized by elongated hyporeflective tumour strands, surrounded by bright collagen (shoal of fish pattern). The overall BCC subtype agreement between LC-OCT and conventional histology was 90.4% (95% CI 79.0\u201396.8). Conclusion: LC-OCT allows noninvasive, real-time identification of BCCs and their subtypes in vertical, horizontal and three-dimension mode compared with histology, RCM and OCT. Further larger studies are needed to better explore the clinical applications of this promising device