Multiple Bifurcation Types and the Linear Dynamics of Ion Sputtered Surfaces

We study the patterns formed on ion sputtered Si surfaces as a function of ion energy and incidence angle, and identify a region in parameter space where the flat surface is stable. The boundaries between the stable and pattern-forming regions represent mathematical bifurcations. Our data set exhibits at least two different bifurcation types. We discuss the constraints imposed by these observations on the correct model of long wavelength dynamics of ion sputtered surfaces.Engineering and Applied Science

Ion-sculpting of Nanopores in Amorphous Metals, Semiconductors and Insulators

We report the closure of nanopores to single-digit nanometer dimensions by ion sculpting in a range of amorphous materials including insulators (SiO$_2$ and SiN), semiconductors (a-Si), and metallic glasses (Pd$_{80}$Si$_{20}$) — the building blocks of a single-digit nanometer electronic device. Ion irradiation of nanopores in crystalline materials (Pt and Ag) does not cause nanopore closure. Ion irradiation of c-Si pores below 100 °C and above 600 °C, straddling the amorphous-crystalline dynamic transition temperature, yields closure at the lower temperature but no mass transport at the higher temperature. Ion beam nanosculpting appears to be restricted to materials that either are or become amorphous during ion irradiation.Engineering and Applied SciencesPhysic

Linear Stability and Instability Patterns in Ion-Sputtered Silicon

We study the patterns formed on Ar+ ion sputtered Si surfaces at room temperature as a function of the control parameters ion energy and incidence angle. We observe the sensitivity of pattern formation to artifacts such as surface contamination and report the procedures we developed to control them. We identify regions in control parameters space where holes, parallel mode ripples and perpendicular mode ripples form, and identify a region where the flat surface is stable. In the vicinity of the boundaries between the stable and pattern forming regions, called bifurcations, we follow the time dependence from exponential amplification to saturation and examine the amplification rate and the wavelength in the exponential amplification regime. The resulting power laws are consistent with the theory of nonequilibrium pattern formation for a Type I (constant-wavelength) bifurcation at low angles and for a Type II (diverging wavelength) bifurcation at high angles. We discuss the failure of all sputter rippling models to adequately describe these aspects of the simplest experimental system studied, consisting of an elemental, isotropic amorphous surface in the simplest evolution regime of linear stabilty.Engineering and Applied Science

Health in times of uncertainty in the eastern Mediterranean region, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

Background The eastern Mediterranean region is comprised of 22 countries: Afghanistan, Bahrain, Djibouti, Egypt, Iran, Iraq, Jordan, Kuwait, Lebanon, Libya, Morocco, Oman, Pakistan, Palestine, Qatar, Saudi Arabia, Somalia, Sudan, Syria, Tunisia, the United Arab Emirates, and Yemen. Since our Global Burden of Disease Study 2010 (GBD 2010), the region has faced unrest as a result of revolutions, wars, and the so-called Arab uprisings. The objective of this study was to present the burden of diseases, injuries, and risk factors in the eastern Mediterranean region as of 2013. Methods GBD 2013 includes an annual assessment covering 188 countries from 1990 to 2013. The study covers 306 diseases and injuries, 1233 sequelae, and 79 risk factors. Our GBD 2013 analyses included the addition of new data through updated systematic reviews and through the contribution of unpublished data sources from collaborators, an updated version of modelling software, and several improvements in our methods. In this systematic analysis, we use data from GBD 2013 to analyse the burden of disease and injuries in the eastern Mediterranean region specifi cally. Findings The leading cause of death in the region in 2013 was ischaemic heart disease (90·3 deaths per 100 000 people), which increased by 17·2% since 1990. However, diarrhoeal diseases were the leading cause of death in Somalia (186·7 deaths per 100 000 people) in 2013, which decreased by 26·9% since 1990. The leading cause of disabilityadjusted life-years (DALYs) was ischaemic heart disease for males and lower respiratory infection for females. High blood pressure was the leading risk factor for DALYs in 2013, with an increase of 83·3% since 1990. Risk factors for DALYs varied by country. In low-income countries, childhood wasting was the leading cause of DALYs in Afghanistan, Somalia, and Yemen, whereas unsafe sex was the leading cause in Djibouti. Non-communicable risk factors were the leading cause of DALYs in high-income and middle-income countries in the region. DALY risk factors varied by age, with child and maternal malnutrition aff ecting the younger age groups (aged 28 days to 4 years), whereas high bodyweight and systolic blood pressure aff ected older people (aged 60–80 years). The proportion of DALYs attributed to high body-mass index increased from 3·7% to 7·5% between 1990 and 2013. Burden of mental health problems and drug use increased. Most increases in DALYs, especially from non-communicable diseases, were due to population growth. The crises in Egypt, Yemen, Libya, and Syria have resulted in a reduction in life expectancy; life expectancy in Syria would have been 5 years higher than that recorded for females and 6 years higher for males had the crisis not occurred. Interpretation Our study shows that the eastern Mediterranean region is going through a crucial health phase. The Arab uprisings and the wars that followed, coupled with ageing and population growth, will have a major impact on the region’s health and resources. The region has historically seen improvements in life expectancy and other health indicators, even under stress. However, the current situation will cause deteriorating health conditions for many countries and for many years and will have an impact on the region and the rest of the world. Based on our fi ndings, we call for increased investment in health in the region in addition to reducing the confl icts

Submaximal Angioplasty for Symptomatic Intracranial Atherosclerotic Disease: A Meta-Analysis of Peri-Procedural and Long-Term Risk

© 2019 by the Congress of Neurological Surgeons. BACKGROUND: Symptomatic intracranial atherosclerotic disease (ICAD) is an important cause of stroke. Although the high periprocedural risk of intracranial stenting from recent randomized studies has dampened enthusiasm for such interventions, submaximal angioplasty without stenting may represent a safer endovascular treatment option. OBJECTIVE: To examine the periprocedural and long-term risks associated with submaximal angioplasty for ICAD based on the available literature. METHODS: All English language studies of intracranial angioplasty for ICAD were screened. Inclusion criteria were as follows: ≥ 5 patients, intervention with submaximal angioplasty alone, and identifiable periprocedural (30-d) outcomes. Analysis was co-nducted to identify the following: 1) periprocedural risk of any stroke (ischemic or hemorrh-agic) or death, and 2) stroke in the territory of the target vessel and fatal stroke beyond 30 d. Mixed effects logistic regression was used to summarize event rates. Funnel plot and rank correlation tests were employed to detect publication bias. The relative risk of periprocedural events from anterior vs posterior circulation disease intervention was also examined. RESULTS: A total of 9 studies with 408 interventions in 395 patients met inclusion criteria. Six of these studies included 113 posterior circulation interventions. The estimated pooled rate for 30-d stroke or death following submaximal angioplasty was 4.9% (95% CI: 3.2%-7.5%), whereas the estimated pooled rate beyond 30 d was 3.7% (95% CI: 2.2%-6.0%). There was no statistical difference in estimated pooled rate for 30-d stroke or death between patients with anterior (4.8%, 95% CI: 2.8%-7.9%) vs posterior (5.3%, 95% CI: 2.4%-11.3%) circulation disease (P \u3e. 99). CONCLUSION: Submaximal angioplasty represents a potentially promising intervention for symptomatic ICAD

NRAS Mutation Is the Sole Recurrent Somatic Mutation in Large Congenital Melanocytic Nevi

Congenital melanocytic nevus (CMN) is a particular melanocytic in utero proliferation characterized by an increased risk of melanoma transformation during infancy or adulthood. NRAS and BRAF mutations have consistently been reported in CMN samples, but until recently results have been contradictory. We therefore studied a series of large and giant CMNs and compared them with small and medium CMNs using Sanger sequencing, pyrosequencing, high-resolution melting analysis, and mutation enrichment by an enhanced version of ice-COLD-PCR. Large–giant CMNs displayed NRAS mutations in 94.7% of cases (18/19). At that point, the role of additional mutations in CMN pathogenesis had to be investigated. We therefore performed exome sequencing on five specimens of large–giant nevi. The results showed that NRAS mutation was the sole recurrent somatic event found in such melanocytic proliferations. The genetic profile of small–medium CMNs was significantly different, with 70% of cases bearing NRAS mutations and 30% showing BRAF mutations. These findings strongly suggest that NRAS mutations are sufficient to drive melanocytic benign proliferations in utero

Study of ion emission from a germanium crystal surface under impact of fast Pb ions in channeling conditions

International audienceA thin germanium crystal has been irradiated at GANIL by Pb beams of 29 MeV/A (charge state Qin = 56 and 72) and of 5.6 MeV/A (Qin = 28). The induced ion emission from the sample entrance surface was studied, impact per impact, as a function of Qin, velocity vin and energy loss DE in the crystal. The Pb ions transmitted through the crystal were analyzed in charge (Qout) and energy using the SPEG spectrometer. The emitted ionized species were detected and analyzed in mass by a Time of Flight multianode detector (LAG). Channeling was used to select peculiar DE in Ge and hence peculiar Pb ion trajectories close to the emitting surface. The experiment was performed in standard vacuum. No Ge emission was found. The dominating emitted species are H+ and hydrocarbon ions originating from the contamination layer on top of the crystal. The mean value of the number of detected species per incoming Pb ion (multiplicity) varies as (Qin/vin)^p, with p values in agreement with previous results. We have clearly observed an influence of the energy deposition DE in Ge on the emission from the top contamination layer. When selecting increasing values of DE, we observed a rather slow increase of . On the contrary, the probabilities of high multiplicity values, that are essentially connected to fragmentation after emission, strongly increase with DE

Fluid modeling of the flow and free surface parameters in the Metaullics LOTUSS system

The growth of aluminum product consumption has placed an emphasis on improving the efficiency of processing internally generated scrap. In the Metaullics LOTUSS System (LOw TUrbulence Scrap Submergence), aluminum machining chips can be melted at a rate in excess of 15 tons per hour with very high recovery efficiencies. A computational fluid dynamics (CFD) model has been implemented to optimize the LOTUSS System to further enhance efficiency and maximize melting performance. Preliminary studies of the CFD modeling will be presented outlining the three-dimensional numerical algorithm for solving the turbulent and free-surface flow inside the LOTUSS system. CFD simulations were carried out for melting system conditions and verified against previous experimental studies. The results indicate that the free surface CFD model is an accurate representation of real-world conditions and the predictions for the position and size of the vortex cone compare very well with the measured experimental values.En raison de la consommation grandissante des produits en aluminium, une attention particuli\ue8re est accord\ue9e \ue0 l\u2019am\ue9lioration de l\u2019efficacit\ue9 du traitement interne des rebuts. Dans le syst\ue8me LOTUSS (LOw TUrbulence Scrap Submergence) de Metaullics, les copeaux d\u2019usinage en aluminium peuvent \ueatre fondus \ue0 une vitesse sup\ue9rieure \ue0 15 tonnes par heure avec une tr\ue8s haute efficacit\ue9 de r\ue9cup\ue9ration. Un mod\ue8le de dynamique des fluides num\ue9rique (DFN) a \ue9t\ue9 mis en \u153uvre pour optimiser le syst\ue8me LOTUSS et ainsi am\ue9liorer son efficacit\ue9 et maximiser la performance de la fusion. Des \ue9tudes pr\ue9liminaires de la mod\ue9lisation par DFN sont pr\ue9sent\ue9es, soulignant l\u2019algorithme num\ue9rique tridimensionnel permettant de r\ue9soudre l\u2019\ue9coulement turbulent et avec surface libre \ue0 l\u2019int\ue9rieur du syst\ue8me LOTUSS. Les simulations par DFN ont \ue9t\ue9 r\ue9alis\ue9es pour des conditions de fusion et v\ue9rifi\ue9es en comparant les r\ue9sultats \ue0 ceux d\u2019\ue9tudes exp\ue9rimentales pr\ue9c\ue9dentes. Les r\ue9sultats indiquent que le mod\ue8le de DFN \ue0 surface libre constitue une repr\ue9sentation ad\ue9quate des conditions r\ue9elles et les pr\ue9dictions sur la position et la taille du vortex se comparent tr\ue8s bien aux valeurs mesur\ue9es exp\ue9rimentalement.Peer reviewed: YesNRC publication: Ye

The Effects of Intravitreal Bevacizumab in Infectious and Noninfectious Uveitic Macular Edema

Background/Aims. To assess the effect of intravitreal bevacizumab injection (IVBI) for the treatment of macular edema due to infectious and noninfectious uveitides. Design. Retrospective interventional case series. Methods. A chart review was performed on all the patients who were diagnosed with uveitic macular edema (UME) and received 1.25 mg of IVBI at two referral centers in Riyadh, Saudi Arabia. All included patients had their visual acuity and macular thickness analyzed at baseline and at 1 and 3 months following IVBI and any sign of reactivation was noted. Results. The mean age of patients was 41±16 years with a mean followup of 4±1 months. Ten patients had idiopathic intermediate uveitis, 9 patients had Behcet’s disease, 10 had idiopathic panuveitis, and twelve patients had presumed ocular tuberculosis uveitis. Following IVBI, the mean LogMAR visual acuity improved from 0.8±0.8 at baseline to 0.4±0.5 at 1 month and 0.3±0.5 at 3 months (P<0.002, at 3 months). The mean macular thickness was 430±132 μm at baseline. Following IVBI macular thickness improved to 286±93 μm at 1 month and to 265±88 μm at 3 months of followup (P<0.001, at 3 months). Conclusion. Bevacizumab was effective in the management of UME associated with both infectious and noninfectious uveitides. Intravitreal bevacizumab induced remission of UME with infectious uveitis and had no immunosuppressive effect against infectious agents