نتایج جستجو برای: growth ring
تعداد نتایج: 935676 فیلتر نتایج به سال:
Nanolithographically patterned copper rings were synthesized, and the self-assembly of the rings into ordered nanoparticle/nanodrop arrays was accomplished via nanosecond pulsed laser heating above the melt threshold. The resultant length scale was correlated to the transport and instability growths that occur during the liquid lifetime of the melted copper rings. For 13-nm-thick rings, a chang...
BACKGROUND AND AIM OF THE STUDY The biodegradable ring was recently developed for mitral and tricuspid annuloplasty. The study aim was to assess the histological biocompatibility of the biodegradable ring and orifice area growth in a porcine model. METHODS The smallest (size 16) biodegradable ring was implanted into the tricuspid annulus of 16 juvenile pigs. All animals were followed up by tr...
three siblings (1 boy, 2 girls) with hypertension and hypokalemia are presented, two with low plasma aldosterone and suppressed renin activity and the eldest with a high renin and aldosterone level due to secondary changes in her kidneys. urinary tetrahydrocortisol (thf) was increased relative to tetrahydrocortisone (the). cortisol ring a reduction constant was also lower than normal. these fin...
Soot samples, including the associated organics, produced from an Illinois No. 6 coal (five samples) and two model compounds, biphenyl (three samples) and pyrene (two samples), have been studied by 13C NMR methods. The coal soot data served as a guide to selection of the temperature range that would be most fruitful for investigation of the evolution of aerosols composed of soot and tars that a...
A short rotation system was possible in the Gmelina arborea plantations due to silvicultural techniques that increased their growth rate. The objective of this research was to determine growth rate effects measured in tree diameter on wood density parameters (mean, minimum, maximum and intra-ring variation) and in fiber dimensions (wall thickness, fiber width, lumen diameter and fiber length) o...
This paper documents tree-ring responses to a historic tornado and re-evaluates prehistoric tree-ring changes seen in archaeological wood of Wupatki Ruin used to date the 11 century eruption of Sunset Crater. The historic tornado occurred at Sunset Crater, northern Arizona, on 24 October 1992, and trees within areas damaged by the tornado survived the event and continue living today. The object...
caffeic acid phenethyl ester(cape) suppresses the growth of transformed cells such as human breast cancer cells, hepatocarcinoma , myeloid leukemia, colorectal cancer cells, fibrosarcoma, glioma and melanoma. a group of heterocyclic esters of caffeic acid was synthesized using mitsunobu reaction and the esters were subjected to further structural modification by electrooxidation of the catechol...
we introduce center-like subsets z*(r,f), z**(r,f) and z1(r,f), where r is a ring and f is a map from r to r. for f a derivation or a non-identity epimorphism and r a suitably-chosen prime or semiprime ring, we prove that these sets coincide with the center of r.
for an arbitrary ring $r$, the zero-divisor graph of $r$, denoted by $gamma (r)$, is an undirected simple graph that its vertices are all nonzero zero-divisors of $r$ in which any two vertices $x$ and $y$ are adjacent if and only if either $xy=0$ or $yx=0$. it is well-known that for any commutative ring $r$, $gamma (r) cong gamma (t(r))$ where $t(r)$ is the (total) quotient ring of $r$. in this...
let r be a prime ring with extended centroid c, h a generalized derivation of r and n ⩾ 1 a xed integer. in this paper we study the situations: (1) if (h(xy))n = (h(x))n(h(y))n for all x; y 2 r; (2) obtain some related result in case r is a noncommutative banach algebra and h is continuous or spectrally bounded.
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