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At least 217 records · Page 12Linked to original sources
PubMed2004

Optimal control approach to suppression of radiationless transitions.

We propose a general approach for eliminating radiationless transitions in polyatomic molecules and illustrate it through the example of the S2-->S1 internal conversion of pyrazine. Essential to our approach is the phenomenon of electronically localized eigenstates of strongly vibronically coupled Hamiltonians. The occurrence of such states, observed here for the first time, and its generality are traced to the origin of scars of periodic orbits.

Journal Article↗
PubMed2004

Toll-like receptor 2 is required for optimal control of Listeria monocytogenes infection.

The control of Listeria monocytogenes infection depends on the rapid activation of the innate immune system, likely through Toll-like receptors (TLR), since mice deficient for the common adapter protein of TLR signaling, myeloid differentiation factor 88 (MyD88), succumb to Listeria infection. In order to test whether TLR2 is involved in the control of infections, we compared the host response in TLR2-deficient mice with that in wild-type mice. Here we show that TLR2-deficient mice are more susceptible to systemic infection by Listeria than are wild-type mice, with a reduced survival rate, increased bacterial burden in the liver, and abundant and larger hepatic microabscesses containing increased numbers of neutrophils. The production of tumor necrosis factor, interleukin-12, and nitric oxide and the expression of the costimulatory molecules CD40 and CD86, which are necessary for the control of infection, were reduced in TLR2-deficient macrophages and dendritic cells stimulated by Listeria and were almost abolished in the absence of MyD88, coincident with the high susceptibility of MyD88-deficient mice to in vivo infection. Therefore, the present data demonstrate a role for TLR2 in the control of Listeria infection, but other MyD88-dependent signals may contribute to host resistance.

Adaptor Proteins, Signal Transducing↗
PubMed1992

Optimal control of myocardial ischaemia: the benefit of a fixed combination of atenolol and nifedipine in patients with chronic stable angina.

OBJECTIVE: To study the effects on myocardial ischaemia of 50 mg of atenolol, 20 mg of slow release nifedipine, and their fixed combination given 12 hourly. DESIGN: A treadmill exercise test and 24 hour ambulatory electrocardiographic monitoring were carried out after a period of five days off treatment (control) and at the end of three weeks of each treatment period. PATIENTS: 23 patients with stable angina pectoris, documented coronary artery disease, and a positive exercise test were randomised in a double blind, three way, cross over study. RESULTS: Compared with the control, nifedipine significantly induced an increase in resting heart rate of (mean (SEM)) 14 (2) beats/min whereas atenolol and the combination significantly reduced it by 24 (2) and 20 (1) beats/min respectively. The number of exercise tests rendered negative after each intervention was five for nifedipine, nine for atenolol, and 11 for the combination. Compared with the control the time to the start of myocardial ischaemia (1 mm ST segment depression) during exercise significantly increased by 3.2 (0.6) min after nifedipine, by 4.6 (0.4) min after atenolol, and by 4.6 (0.5) min after the combination; rate-pressure product (beats/min. mm Hg) at 1 mm ST segment depression increased by 2824 (970) after nifedipine but fell by 4436 (900) and 4501 (719) after atenolol and the combination. The weekly frequency of angina was reduced from a mean of five while taking nifedipine, to three while taking atenolol, and to two while taking the combination. The total ischaemic time during ambulatory monitoring was significantly reduced from 69 (17) min during control to 37.5 (9.8) min during nifedipine, to 15.6 (5.5) min during atenolol, and to 6.5 (2.7) min during the combination. CONCLUSION: The undesirable effect of a high basal heart rate induced by nifedipine was neutralised by its combination with atenolol. Whereas atenolol and the combination were equally efficacious in controlling exercise induced ischaemia, the combination was more effective in reducing total ischaemic burden.

Adult↗
PubMed1996

Optimal control of acute cisplatin-induced emesis.

A survey by Coates and co-workers in 1983 revealed that patients ranked nausea and vomiting as the most distressing side effects of chemotherapy. In the last decade the use of high-dose metoclopramide and, especially, the introduction of the 5-HT3 receptor antagonists, have been major leaps forward in the control of chemotherapy-induced emesis. Nevertheless, since patients still consider nausea and vomiting to be the most distressing side effect of their chemotherapy there is clearly a need for further improvements. Acute emesis, which is the topic of this review, can now be controlled in the majority of patients during their first course of chemotherapy. Future focus should be on better control of emesis during subsequent courses of chemotherapy as well as on better control of delayed emesis.

Antiemetics↗
PubMed2003

Optimizing control of acromegaly: integrating a growth hormone receptor antagonist into the treatment algorithm.

Acromegaly is associated with significant morbidities and a 2- to 3-fold increase in mortality because of the excessive metabolic action of GH and IGF-I, a marker of GH output. Reductions in morbidity correspond with decreases in IGF-I, and mortality is lowered following normalization of IGF-I or GH levels. Therefore, this has become an important end point. Current guidelines for the treatment of acromegaly have not considered recent advances in medical therapy, in particular, the place of pegvisomant, a GH receptor antagonist. Treatment goals include normalizing biochemical markers, controlling tumor mass, preserving pituitary function, and relieving signs and symptoms. Surgery reduces tumor volume and is considered first-line therapy. Radiation reduces tumor volume and GH and IGF-I levels, but the onset of action is slow and hypopituitarism typically develops. Therefore, pharmacotherapy is often used following surgery or as first-line therapy for nonresectable tumors. Dopamine agonists can be considered in patients exhibiting minimal disease or those with GH-prolactin-cosecreting tumors but will not achieve hormone normalization in most patients. Somatostatin analogs effectively suppress GH and IGF-I in most patients, but intolerance (e.g. diarrhea, cramping, gallstones) can occur. Pegvisomant, the newest therapeutic option, blocks GH action at peripheral receptors, normalizes IGF-I levels, reduces signs and symptoms, and corrects metabolic defects. Pegvisomant does not appear to affect tumor size and has few adverse effects. Pegvisomant is the most effective drug treatment for acromegaly in normalizing IGF-I and producing a clinical response; it is the preferred agent in patients resistant to or intolerant of somatostatin analogs.

Acromegaly↗
PubMed2002

Optimal control of laser beams for propagation through a turbulent medium.

Concerning the problem of transmitting a laser beam from one telescope to another telescope through a turbulent medium, it is established that using an adaptive optical system on both telescopes to precompensate an outgoing laser beam based on the aberrations measured on the received laser beam leads to an iteration that maximizes the transmission (neglecting attenuation losses) of laser power between the telescopes. Simulation results are presented demonstrating the effectiveness of this technique when the telescopes are equipped with either phase-only or full-wave compensation systems. Simulation results are shown that indicate that for a uniform distribution of the strength of turbulence, 95% transmission of laser power is attained when both telescopes can achieve full-wave compensation provided that the aperture diameter D of the two telescopes is greater than twice the Fresnel length square root of lambdaL, where A is the wavelength of propagation and L is the distance between the two telescopes.

Journal Article↗