Experimental observation of the Aubry transition in two-dimensional colloidal monolayers

The possibility to achieve entirely frictionless, i.e. superlubric, sliding between solids, holds enormous potential for the operation of mechanical devices. At small length scales, where mechanical contacts are well-defined, Aubry predicted a transition from a superlubric to a pinned state when the mechanical load is increased. Evidence for this intriguing Aubry transition (AT), which should occur in one dimension (1D) and at zero temperature, was recently obtained in few-atom chains. Here, we experimentally and theoretically demonstrate the occurrence of the AT in an extended two-dimensional (2D) system at room temperature using a colloidal monolayer on an optical lattice. Unlike the continuous nature of the AT in 1D, we observe a first-order transition in 2D leading to a coexistence regime of pinned and unpinned areas. Our data demonstrate that the original concept of Aubry does not only survive in 2D but is relevant for the design of nanoscopic machines and devices at ambient temperature.Comment: 12 pages including 4 figures + 9 pages supplemental informatio

Ocorrência de insetos predadores de pulgões em cultivo orgânico de couve em sistema solteiro e consorciado com adubos verdes.

bitstream/CNPAB-2010/34509/1/cot101.pdfParceria: UFRR

Acid digestion for cadmium determination in mineral salt mixing for animal nutrition by thermospra y flame furnace Atomic absorption spectrometry.

Cadmium was determined in a sample of mineral salt mixing to milk cattle that has been preparing to be a reference material. A volume of 3 mL of HNO3 3.0 mol L-1 plus 2.0 of H202 30% (W w-1) was added to 250 mg of sample in a cavity microwave oven. After digestion performance the volume was adjusted to 10 mL with water, centrifuged and the supernatant determined by thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS). The system consist of a peristaltic pump, a lab-made commutator injector, and the thermospray flame furnace unit, which includes the ceramic capillary (0.5 mm 10,2.0 mm ED and 100 mm of length) and the Ni tube (10 cm) which is located on the AAS burner. For reaching a higher temperature inside the tube, six holes of 2 mm diameter were drilled in the bottom of the tube. Another orifice was drilled at 90' to the bottom holes for inserting the thermospray capillary. The capillary tip is about 1 mm inside the tube furnace. The manifold was assembled with 0.5 mm i.d. PTFE tubing, sample volume of 1 00 uL, 0.5 mL min-1 of flow rate, and 0.5 % (w v-1) EDTA plus 0.1 % (v v-1) Triton X 100 as carrier stream. Limits of detection (LOD) and quantification (LOQ) 'obtained were 0.31~g L-1 and 1.02~gL-1, respectively. The obtained results were 402 +- 35ug L-1. The accuracy was checked by performing GFAAS (465 +-95ug L-1) and the results proved to be similar by using t test. The high rsd in the GFAAS was probably due the high chloride sample amount

Clinical effectiveness and safety of analogue glargine in type 1 diabetes : systematic review and meta-analysis

INTRODUCTION: The use of insulin analogues for the treatment of type 1 diabetes mellitus (T1DM) is widespread; however, the therapeutic benefits still require further evaluation given their higher costs. Objective: To evaluate the effectiveness and safety of Analogue Glargine (AG) compared to Recombinant DNA insulin (rDNA) in patients with DM1 in observational studies, building on previous reviews of RCTs comparing NPH insulin and AG. METHODS: A systematic review (SR) with meta-analysis. The SR included cohort studies and registries available on PUBMED, LILACS, and CENTRAL as well as manual and gray literature searches. The meta-analysis was conducted in Review Manager ® 5.2 software. The primary outcomes were: glycohemoglobin (Hb1Ac), weight gain and hypoglycemia. Methodological quality was assessed using the Newcastle-Ottawa scale. RESULTS: Out of 796 publications, 11 studies were finally included. The meta-analysis favored AG in Hb1Ac outcomes (adult patients) and hypoglycemic episodes (p <0.05), but without reaching glycemic control (Hb1Ac to approximately 7%). The methodological quality of the studies was moderate, noting that 45% of studies were funded by pharmaceutical companies. CONCLUSION: Given the high heterogeneity of the studies, the discrete value presented by the estimated effect on effectiveness and safety, potential conflicts of interest of the studies and the appreciable higher cost of AG, there is still no support for recommending first line therapy with analogues. The role of analogues in the treatment DM1 could be better determined by further observational studies of good methodological quality to assess their long-term effectiveness, safety as well as cost-effectiveness

Macromastia: a Risk Factor for Carpal Tunnel Syndrome?

PURPOSE: To evaluate the prevalence of carpal tunnel syndrome (CTS) in a cohort of women with macromastia and to assess the evolution of the CTS signs and symptoms after breast surgery. POPULATION: A series of 123 women was evaluated. CTS was defined by co-existence of symptoms, two physical findings and electrophysiological evaluation. One year after reduction mammaplasty, the 22 patients who had been diagnosed CTS were re-evaluated. RESULTS: CTS group of women had a mean age of 38.8 years, mean body mass index of 28.5 kg/m(2) and mean breast size of 35.9 cm. Age and nipple-to-sternal notch distance were statistically significantly associated with CTS (p = 0.001 and p = 0.001, respectively). A year after surgery 15 patients were re-assessed: nine patients reported absence or improvement of CTS symptoms while six patients reported symptoms persistence or worsening. CONCLUSION: Age, breast size, but not body mass index, have a positive correlation with the CTS.info:eu-repo/semantics/publishedVersio

Abscisic acid on the quality of tomato fruits.

The use of abscisic acid (ABA) in agriculture has increased in the last few years due to the increase in ABA commercial availability at lower costs. The objective of this study was to determine the effect of exogenous ABA on tomato fruit quality parameters such as soluble solids (SS), total and soluble pectins, titratable acidity (TA) and flesh firmness. Tomatoes from the cultivar ?Santa Clara? were the study followed a complete randomized block desig, with four treatments in five repetitions. The treatments were plants not treated with ABA (control), foliar sprayed with ABA at 500 mg L -1, 150 mLdrench with ABA at 500 mg L-1, or foliar plus drench treated with ABA. After harvesting, the physicochemical characteristics of the fruits were evaluated in the laboratory. All treatments were weekly applied to the plants from anthesis to harvest at fully maturity. Root treatment increased SS by up to 26.12%, increased ratio SS/TA, firmness and decreased soluble pectin. According to the results, it can be concluded that the application of ABA to leaves and roots can improve fruit quality by increasing the SS, ratio SS/TA. The method of application affects the SS content

Avaliação das características enológicas da cv. Alicante Bouschet produzida em uma região tropical, no Nordeste do Brasil.

O objetivo deste trabalho foi avaliar as características das uvas e do vinho elaborado a partir da cultivar Alicante Bouschet, instalada em fevereiro de 2001 em um solo tipo aluvião, sendo as plantas enxertadas sobre IAC-572 (Vitis caribaea e 101-14 Mgt) e irrigadas por gotejamento