Effect of synthesis temperature on crystallinity, morphology and cell viability of nanostructured hydroxyapatite via wet chemical precipitation method: Effect of temperature on hydroxyapatite properties

Hydroxyapatite (HA) is the main natural mineral constituent of bones and is a good alternative for biomedical applications because it is osteoconductive, non-allergenic, and non-carcinogenic, which ensures high biocompatibility. A commonly used method for obtaining hydroxyapatite is the wet route, which is simple and low-cost, produces only water as a final residue, and provides HA with a crystallinity comparable to that of bone tissue, which favors its biocompatibility. Therefore, the objective of this work is to synthesize hydroxyapatite via the wet chemical precipitation method at different temperatures (4°C, 30°C, 50°C, or 70°C) to observe the influence of temperature on crystallinity, morphology, and cytotoxicity. The results of X-ray diffraction show that all syntheses resulted in pure hydroxyapatite, while increasing the temperature led to higher crystallinity (10.6% to 56.2%) and the crystal size was slightly affected. The increase in temperature changed the particle shape from irregular to needle-like. Cell viability was tested by PicoGreen® in VERO cells for samples at concentrations of 30 and 300µg/mL, and the samples synthesized at 4°C, with lower crystallinity, caused less DNA damage to cells compared to the negative control. &nbsp

Long-range and short-range dihadron angular correlations in central PbPb collisions at √sNN=2.76 TeV

This is the pre-print version of the Published Article, which can be accessed from the link below.First measurements of dihadron correlations for charged particles are presented for central PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76TeV over a broad range in relative pseudorapidity ( ) and the full range of relative azimuthal angle ( ). The data were collected with the CMS detector, at the LHC. A broadening of the away-side ( ) azimuthal correlation is observed at all , as compared to the measurements in pp collisions. Furthermore, long-range dihadron correlations in are observed for particles with similar values. This phenomenon, also known as the \ridge", persists up to at least j j = 4. For particles with transverse momenta (pT) of 2-4 GeV/c, the ridge is found to be most prominent when these particles are correlated with particles of pT = 2-6 GeV/c, and to be much reduced when paired with particles of pT = 10-12 GeV/c

Demanda energética e mobilização do solo com o uso de escarificadores em sistemas de semeadura direta

A redução das janelas de semeadura e a intensificação da produção no sistema de semeadura direta impulsionaram o aumento na frequência de utilização de máquinas, provocando compactação pelo tráfego. A compactação, além de prejudicar o desenvolvimento das raízes das plantas, aumenta a demanda de potência dos implementos justificando a utilização de escarificadores para a descompactação do solo. Avaliou-se o desempenho de dois escarificadores (Haste + ponteira), sendo um comercial e um experimental, com vistas a entender a operação de escarificação quando adaptada ao sistema de semeadura direta, utilizando como parâmetros variáveis energéticas e de solo. O elemento descompactador experimental teve um desempenho superior ao comercial nas principais variáveis estudadas, tais como consumo de combustível, potência e força de tração. Quando à frente dos elementos descompactadores o disco de corte não alterou a força de tração mas reduziu o consumo de combustível e a potência. O aumento da velocidade proporcionou incremento da força de tração, potência e consumo de combustível

Effect of different conductor tubes on the longitudinal distribution of corn seeds

ABSTRACT The correct longitudinal distribution of seeds by the seeder machine is one of the features that most contributes to obtain an adequate plant stand and good crop yield. The objective of this study was to evaluate the longitudinal distribution of corn seeds by seed conductor tube types, combined with a horizontal perforated disc and a pneumatic meter, altering the seeding density rate. The experiment was conducted in a laboratory using a seed meter test bench. Treatments were a combination of two seed meters, six conductor tubes and four peripheral speeds for the meter disc, corresponding to densities of 60, 70, 80 and 90 thousand corn seeds per hectare and were organized in a three-factor scheme with four repetitions. By increasing the seeding rate into the same ground speed, there was a reduction in the percentage of acceptable spacing, this effect being more pronounced when conductor tubes with a small diameter and straight profile were used

Effect of different conductor tubes on the longitudinal distribution of corn seeds

<div><p>ABSTRACT The correct longitudinal distribution of seeds by the seeder machine is one of the features that most contributes to obtain an adequate plant stand and good crop yield. The objective of this study was to evaluate the longitudinal distribution of corn seeds by seed conductor tube types, combined with a horizontal perforated disc and a pneumatic meter, altering the seeding density rate. The experiment was conducted in a laboratory using a seed meter test bench. Treatments were a combination of two seed meters, six conductor tubes and four peripheral speeds for the meter disc, corresponding to densities of 60, 70, 80 and 90 thousand corn seeds per hectare and were organized in a three-factor scheme with four repetitions. By increasing the seeding rate into the same ground speed, there was a reduction in the percentage of acceptable spacing, this effect being more pronounced when conductor tubes with a small diameter and straight profile were used.</p></div