115 research outputs found
Immunoglobulins from motoneurone disease patients enhance glutamate release from rat hippocampal neurones in culture
No full text1. The whole-cell configuration of the patch-clamp technique was used to study the effects of immunoglobulins (IgGs) from patients affected by amyotrophic lateral sclerosis (ALS) on spontaneous glutamatergic currents in rat hippocampal cells in culture. 2. Focal application of ALS IgGs (100 mu g ml(-1)) to hippocampal cells induced a rise in frequency but not in amplitude of spontaneous excitatory postsynaptic currents (SEPSC) which outlasted the period of IgG application. The mean frequency ratio (ALS over control) was 3.2 +/- 0.6 (n = 19). No changes in frequency or amplitude of SEPSCs were observed after treatment with IgGs obtained from healthy donors (n = 5) or from patients with Alzheimer's disease (n = 4).
3. ALS IgGs also increased the frequency (by a factor of 2.0 +/- 0.3) but not the amplitude of miniature excitatory postsynaptic currents (mEPSC) recorded in the presence of TTX (n = 19). A rise in frequency of mEPSC was also seen in cells superfused with a calcium-free solution (n = 4).
4. In the presence of TTX, ALS IgGs did not modify the amplitude or the shape of currents evoked by AMPA (100 mu M), recorded at a holding potential of -50 mV.
5. It is concluded that ALS IgGs enhance both SEPSCs and mEPSCs through a presynaptic type of action. The excessive release of glutamate from nerve endings may be the cause of motoneurone death in ALS patients
On monotone solutions of some classes of difference equations
No full textWe describe a method for finding monotone solutions of some
classes of difference equations converging to the corresponding
equilibria. The method enables us to confirm three conjectures
posed by the present author in a talk, which are extensions of
three conjectures by M. R. S. Kulenović and G. Ladas,
Dynamics of Second Order Rational Difference Equations.
With Open Problems and Conjectures. Chapman and Hall/CRC, 2002.
It is interesting that the method, in some cases, can be applied
also when the parameters are variable
Iron Oxide Nanoparticles Synthesized from Iron Waste as an Additive to Lubricants for Reducing Friction
No full textDevelopment of sustainable routes for nanoparticle synthesis is one of the important research issues in waste management. Herein, we synthesized the nano iron oxide-cubic (NIO-C) nanoparticles from iron waste sludge for application as additive in polyethylene glycol (PAG46) lubricant. X-ray diffraction (XRD) evidenced the presence of maghemite as a dominant phase of the NIO-C nanoparticles, having (311) crystallographic plane at the diffraction angle of 35.27°. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of cubic maghemite of ~ 20 nm in size. The NIO-C nanoparticles served as the additive in the PAG46 lubricant, showing a decrease in the coefficient of friction by 46% at 25 °C and by 36% at 80 °C. Reducing the coefficient of friction was assigned to the cubic NIO-C fractions, enhancing the smoothness of the metal plates. This study describes economic and environmentally sustainable method for producing cubic maghemite nanoparticles. Graphical Abstract: [Figure not available: see fulltext.
Асимптотична поведінка розв'язків нелінійного різницевого рівняння з неперервним аргументом
No full textWe consider the difference equation with continuous argument
x(t+2)−2λx(t+1)+λ²x(t)=f(t,x(t)),
where λ > 0, t ∈ [0, ∞), and f: [0, ∞) × R → R. Conditions for the existence and uniqueness of continuous asymptotically periodic solutions of this equation are given. We also prove the following result: Let x(t) be a real continuous function such that
limt→∞(x(t+2)−(1−α)x(t+1)−αx(t))=0
for some α ∈ R. Then it always follows from the boundedness of x(t) that
limt→∞(x(t+1)−x(t))=0
t → ∞ if and only if α ∈ R {1}.Розглянуто різницеве рівняння з меперершшм аргумен том
x(t+2)−2λx(t+1)+λ²x(t)=f(t,x(t)),
де λ>0,t∈[0,∞) та f:[0,∞)×R→R. Навелено умови ісііування та єдності неперервних асимптотично періодичних розв'язків даного рівнянняя. Доведено також наступне твердження: Нехай x(t) — дійсна непервнаа функція така, що
limt→∞(x(t+2)−(1−α)x(t+1)−αx(t))=0
для деякого α∈R. У цьому випадку з обмеженості x(t) завжди випливає, що
limt→∞(x(t+1)−x(t))=0
тоді і тільки годі, коли α∈R{1}
The Proper Role of Discretion in Political Asylum Determinations
No full textThis Article examines the limits of discretion in asylum adjudications. The author describes recent administrative and judicial decisions regarding discretion, including the Supreme Court decision in INS v. Stevic. The author continues on to analyze the limits of administrative discretion under the Refugee Act of 1980 and international law, including the Protocol relating to the Status of Refugees and customary international legal principles respecting family reunification. The author concludes that an unprincipled expansion of the role of discretion in asylum cases could threaten the right to apply for asylum in the United States
On Bloch-Type Functions with Hadamard Gaps
No full textWe give some sufficient and necessary conditions for an analytic function f on the unit ball B with Hadamard gaps, that is, for f(z)=∑k=1∞Pnk(z) (the homogeneous polynomial expansion of f) satisfying nk+1/nk≥λ>1 for all k∈ℕ, to belong to the space ℬpα(B)={f|sup0<r<1(1−r2)α\|ℛfr\|p<∞,f∈H(B)}, p=1,2,∞ as well as to the
corresponding little space. A remark on analytic functions with Hadamard gaps on mixed norm space on the unit disk
is also given
Eventually Periodic Solutions of a Max-Type Difference Equation
No full textWe study the following max-type difference equation xn=max{An/xn-r,xn-k}, n=1,2,…, where {An}n=1+∞ is a periodic sequence with period p and k,r∈{1,2,…} with gcd(k,r)=1 and k≠r, and the initial conditions x1-d,x2-d,…,x0 are real numbers with d=max{r,k}. We show that if p=1 (or p≥2 and k is odd), then every well-defined solution of this equation is eventually periodic with period k, which generalizes the results of (Elsayed and Stevic´ (2009), Iričanin and Elsayed (2010), Qin et al. (2012), and Xiao and Shi (2013)) to the general case. Besides, we construct an example with p≥2 and k being even which has a well-defined solution that is not eventually periodic
Weighted Composition Operators from Logarithmic Bloch-Type Spaces to Bloch-Type Spaces
No full textThe boundedness and compactness of the weighted composition operators from to Bloch-type spaces are studied here. © 2009 S. Stević and R. P. Agarwal
- …
