Učinak temperature i dodatka indija na mehanička svojstva legure Al–0.21wt%Au

Tensile characteristics of both Al–0.21wt%Au and Al–0.21wt%Au–0.21wt%In alloys were investigated in the temperature range 493 K to 553 K. The coefficient of work hardening, χ = ∂σ2/∂², yield stress, σy, and fracture stress, σf , decreased with increasing deformation temperature (T) and exhibited abrupt increase at about 523 K. On the other hand, the fracture strain, ²f , and dislocation slip distance, L, increased with increasing deformation temperature and exhibited minima at about 523 K. The activation energy was determined in the range around 523 K to clarify the observed change in the behaviour of the hardening characteristics of the investigated samples.Istraživali smo istezna svojstva legura Al–0.21wt%Au i Al–0.21wt%Au–0.21wt%In na temperaturama 493 K do 553 K. Koeficijent mehaničkog očvršćivanja, χ = ∂σ2/∂², granica elastičnosti, σy, i granica loma, σf , smanjuju se pri povišenim temperaturama istezanja (T) te pokazuju nagao porast na oko 523 K. Nasuprot tome, lomno istezanje, ²f , i prosječna duljina klizanja dislokacija, L, povećali su se s povišenom temperaturom istezanja, a pokazuju i minimum na oko 523 K. Radi objašnjenja opaženih promjena u procesu očvršćivanja ispitivanih uzoraka odredili smo aktivacijsku energiju na temperaturama oko 523 K

Učinak temperature i dodatka indija na mehanička svojstva legure Al–0.21wt%Au

Tensile characteristics of both Al–0.21wt%Au and Al–0.21wt%Au–0.21wt%In alloys were investigated in the temperature range 493 K to 553 K. The coefficient of work hardening, χ = ∂σ2/∂², yield stress, σy, and fracture stress, σf , decreased with increasing deformation temperature (T) and exhibited abrupt increase at about 523 K. On the other hand, the fracture strain, ²f , and dislocation slip distance, L, increased with increasing deformation temperature and exhibited minima at about 523 K. The activation energy was determined in the range around 523 K to clarify the observed change in the behaviour of the hardening characteristics of the investigated samples.Istraživali smo istezna svojstva legura Al–0.21wt%Au i Al–0.21wt%Au–0.21wt%In na temperaturama 493 K do 553 K. Koeficijent mehaničkog očvršćivanja, χ = ∂σ2/∂², granica elastičnosti, σy, i granica loma, σf , smanjuju se pri povišenim temperaturama istezanja (T) te pokazuju nagao porast na oko 523 K. Nasuprot tome, lomno istezanje, ²f , i prosječna duljina klizanja dislokacija, L, povećali su se s povišenom temperaturom istezanja, a pokazuju i minimum na oko 523 K. Radi objašnjenja opaženih promjena u procesu očvršćivanja ispitivanih uzoraka odredili smo aktivacijsku energiju na temperaturama oko 523 K

Caracterización estructural y actividad biológica de sulfolípidos de algas marinas seleccionadas

The sulfolipid classes (SLs) in the total lipids of five species of marine algae, two species of Rhodophyta (Laurencia popillose, Galaxoura cylindriea), one species of Chlorophyta (Ulva fasciata), and two species of Phaeophyta (Dilophys fasciola, Taonia atomaria) were separated and purified on DEAE-cellulose column chromatography. The SLs component was identified by IR, gas chromatography MS/MS and liquid chromatography MS/MS. The level of SLs contents va ried from 1.25% (in L. papillose) to 11.82% (in D. fasciola) of the total lipid contents. However, no significant differences in sulfate content (0.13 – 0.21%) were observed among all these algae species. All SLs were characterized by high contents of palmitic acid (C 16:0), which ranged from 30.91% in G. cylindriea to 63.11% in T. atomatia. The main constitutes of algal sulfolipids were identified as sulfoquinovosyl-di-acylglycerol and sulfoquinovosyl acylglycerol. The sulfolipids of different algal species exhibited remarkable antiviral activity against herps simplex virus type 1 (HSV-1) with an IC50 ranging from 18.75 to 70. 2 μg mL–1. Moreover, algal sulfolipid inhibited the growth of the tumor cells of breast and liver human cancer cells with IC50 values ranging from 0.40 to 0.67 μg mL–1 for human breast adenocarcinoma cells (MCF7).Se separaron diferentes clases sulfolípidos (SL) a partir de los lípidos totales de cinco especies de algas marinas: una especie de Chlorophyta (Ulva fasciata), dos especies de Phaeophyta (Dilophys fasciola, Taonia atomaria) y dos especies de Rhodophyta (Laurencia popillose, Galaxoura cylindriea) que se purificaron mediante cromatografía en columna de DEAE-celulosa. Los components de SLs fueron identificados por IR, cromatografía de gases MS/MS y cromatografía líquida MS/ MS. Los contenidos de SL en relación al total de lípidos varió de 1,25% (en L. papilosa) al 11,82% (en D. fasciola). Sin embargo, no hay diferencias significativas en el contenido de sulfato observado entre todas estas especies de algas (desde 0,13 hasta 0,21%). Todos los SL se caracterizaron por un alto contenido de ácido palmítico (C16:0), que osciló entre 30,91% en G. cylindriea a 63,11% en T. atomatia. Sulfoquinovosyl-di-acilglicerol y acilglicerol sulfoquinovosyl fueron identificados como los principales constituyentes de los sulfolípidos de estas algas. Los sulfolípidos de las diferentes especies de algas estudiadas mostraron una notable actividad antiviral contra el virus del herpes simple tipo 1 (VHS-1) con una IC50 que osciló entre 18,75 y 70. 2 g mL–1. Por otra parte, los sulfolípidos de estas algas inhibieron el crecimiento de células tumorales de mama y células de cáncer de hígado humano con valores de IC50 que van desde 0,40 hasta 0,67 g mL–1 para las células de adenocarcinoma de mama humano (MCF7)

The semileptonic decays of the B_c meson

We study the semileptonic transitions B_c to \eta_c, J/\psi, D, D^*, B, B^*, B_s, B_s^* in the framework of a relativistic constituent quark model. We use experimental data on leptonic J/\psi decay, lattice and QCD sum rule results on leptonic B_c decay, and on radiative \eta_c transitions to adjust the quark model parameters. We compute all form factors of the above semileptonic B_c-transitions and give predictions for various semileptonic B_c decay modes including their \tau-modes when they are kinematically accessible. The implications of heavy quark symmetry for the semileptonic decays are discussed and are shown to be manifest in our explicit relativistic quark model calculation. A comparison of our results with the results of other calculations is performed.Comment: 31 pages Latex (uses epsf, revtex). Section II expanded, typos corrected. This version will appear in Phys. Rev.

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112