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Among the most striking aspects of the movement of many animal groups are their sudden coherent changes in direction. Recent observations of locusts and starlings have shown that this directional switching is an intrinsic property of their motion. Similar direction switches are seen in self-propelled particle and other models of group motion. Comprehending(More)
Preeclampsia is a human syndrome characterized by elevated maternal blood pressure and proteinuria. It is the main cause of maternal morbidity and mortality, and fetal metabolic disturbances in developed and developing countries. Fetal complications in preeclampsia have been related with lower placental blood flow. The placenta lacks of innervation, thus(More)
We consider the switching rate of a metastable reaction scheme, which includes reactions with arbitrary steps, e.g., kA<-->(k+r)A (both forward and reverse reaction steps are allowed to happen). Employing a WKB approximation, controlled by a large system size, we evaluate both the exponent and the preexponential factor for the rate. The results are(More)
Pre-eclampsia is associated with elevated maternal blood pressure and proteinuria, altered fetal growth, and increased plasma adenosine concentration in the mother and the fetus. Human equilibrative nucleoside transporters 1 (hENT1) and hENT2 are crucial to maintain physiological plasma levels of adenosine, thus modulating its several biological effects(More)
The evolution of a system of chemical reactions can be studied, in the eikonal approximation, by means of a Hamiltonian dynamical system. The fixed points of this dynamical system represent the different states in which the chemical system can be found, and the connections among them represent instantons or optimal paths linking these states. We study the(More)
The root cause of preeclampsia is the placenta. Preeclampsia begins to abate with the delivery of the placenta and can occur in the absence of a fetus but with the presence of trophoblast tissue with hydatidiform moles. In view of this, study of the placenta should provide insight into the pathophysiology of preeclampsia. In this presentation we examine(More)
Up regulation of the transforming growth factor-beta 1 (TGF-beta1) axis has been recognized as a pathogenic event for progression of glomerulosclerosis in diabetic nephropathy. We demonstrate that glomeruli isolated from diabetic rats accumulate up to sixfold more extracellular adenosine than normal rats. Both decreased nucleoside uptake activity by the(More)
Nitric oxide (NO) is an endogenous vasodilator molecule synthetized from L-arginine by a family of nitric oxide synthases. In differentiated human endothelial cells, it is well known that L-arginine uptake via cationic amino acid transporters (y(+)/CAT) or system y(+)L is required for the NO synthesis via endothelial nitric oxide synthase, but there are no(More)
OBJECTIVES To evaluate the association between endothelial activation markers in the maternal circulation with nitric oxide (NO) synthesis in human umbilical endothelial cells. STUDY DESIGN This is a case-control study of normal and pre-eclamptic pregnancies. The levels of sE-selectin, soluble vascular cell adhesion molecule 1 (sVCAM-1), and soluble(More)
(typed, double-spaced) in length and may be subject to editing or abridgment. we conducted a prospective study approved by the Bioethics Committee. 2,3 There were included 68 healthy pregnant women, primigravidae, younger than 25 years, and attending the Hospital Gineco Obstetrico Isidro Ayora in Quito, Ecuador. All women were included at 16 weeks of(More)