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Results for “Optimism”

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PubMed2006

Hemagglutinin (HA) proteins from H1 and H3 serotypes of influenza A viruses require different antigen designs for the induction of optimal protective antibody responses as studied by codon-optimized HA DNA vaccines.

Effective antibody responses provide crucial immunity against influenza virus infection. The hemagglutinin (HA) protein is the major target of protective antibody responses induced by viral infection and by vaccination with both inactivated and live-attenuated flu vaccines, but knowledge about the optimal designs of protective HA antigens from different flu serotypes is still limited. In this study, we have significantly improved the immunogenicity of HA-expressing DNA vaccines by using codon-optimized HA sequences for either an H1 serotype (A/NewCal/20/99) or an H3 serotype (A/Panama/2007/99) human influenza A virus and then used these constructs as model antigens to identify the optimal HA antigen designs to elicit high-level protective antibody responses. Two forms of HA antigen, a wild-type, full-length HA and a secreted form with transmembrane (TM) domain-truncated HA, were produced. Both forms of HA DNA vaccines, from either H1 or H3 serotypes, were able to elicit high levels of HA-specific immunoglobulin G responses in immunized rabbits as measured by enzyme-linked immunosorbent assay. Interestingly, the abilities of H1 HA and H3 HA antigens to elicit hemagglutination inhibition (HI) and neutralizing antibody (NAb) responses differ. For the H1 HA antigens, the full-length HA induced significantly higher HI and NAb responses than did the TM-truncated HA. For the H3 HA antigen, both the full-length HA and TM-truncated HA induced high levels of HI and NAb responses. These data indicate that H1 and H3 antigens have different expression requirements for the induction of an optimal protective antibody response and that the structure integrity of HA antigens is critical for eliciting type-specific protective antibody responses. Our findings will have an important impact on future subunit-based flu vaccine development.

Animals↗

PubMed1998

'Optimal' directional coronary atherectomy: final results of the Optimal Atherectomy Restenosis Study (OARS).

BACKGROUND: Previous clinical trials of directional coronary atherectomy (DCA) have failed to show significant improvement in early or late outcomes compared with balloon angioplasty (PTCA). The present study tested the hypothesis that more aggressive "optimal" atherectomy could be performed safely to produce larger initial lumen diameters and a lower late restenosis rate. METHODS AND RESULTS: The present study was a prospective multicenter registry of consecutive patients undergoing optimal DCA of de novo or restenotic lesions in 3.0- to 4.5-mm native coronary arteries. Optimal DCA was defined as using a 7F atherectomy device and adjunctive PTCA if necessary to achieve a < 15% residual stenosis. Six-month angiographic and 1-year clinical follow-up was planned in all patients. A total of 199 patients with 213 lesions met eligibility criteria for enrollment. Short-term procedural success was achieved in 97.5%, with a major complication rate (death, emergency bypass surgery, or Q-wave myocardial infarction [MI]) of 2.5%. There were no early deaths. Non-Q-wave MI (CK-MB > 3 times normal) occurred in 14% of patients. Mean reference vessel diameter was 3.28 mm. Mean diameter stenosis was reduced from 63.5% to a final stenosis of 7%. Late 1-year clinical follow-up revealed one cardiac death and a target lesion revascularization rate of 17.8%. The angiographic restenosis rate at 6 months was 28.9%, with the major predictor of restenosis being a smaller postprocedure lumen diameter. CONCLUSIONS: Optimal DCA produced a low residual percent diameter stenosis and a lower restenosis rate than seen in previous trials without an increase in early or late major adverse events.

Aged↗

PubMed2002

Optimism and adaptation to chronic disease: The role of optimism in relation to self-care options of type 1 diabetes mellitus, rheumatoid arthritis and multiple sclerosis.

OBJECTIVES: To determine the role of optimistic beliefs in adaptation processes of three chronic diseases different in controllability by self-care. It was expected that optimism towards the future would relate to adaptation independently of the controllability of disease. Optimism regarding one's coping ability should be beneficial in controllable diseases. Unrealistic optimism was expected to be beneficial in uncontrollable disease. DESIGN: The cross-sectional design involved 104 patients with type 1 diabetes, 95 patients with rheumatoid arthritis and 98 patients with multiple sclerosis, recruited via their physician at the out-patient department of five hospitals. METHOD: Confirmatory Factor Analysis (LISREL) was employed to confirm a three-dimensional approach of optimism: outcome expectancies, efficacy expectancies and unrealistic thinking. Multi-sample analysis by path modelling was used to examine whether the relationship of the three optimistic beliefs with coping (CISS-21), depression and anxiety (HADS), and physical functioning (SF-36) differs with the controllability based on the self-care options of chronic disease. RESULTS: These show that when chronic disease must be controlled by self-care, physical health depends more strongly on positive efficacy expectancies. In contrast, when self-care options for controlling chronic disease are limited, physical health depends more strongly on positive unrealistic thinking and relates negatively to positive efficacy expectancies. The impact of the three optimistic beliefs on mental health is independent of the controllability by self-care. CONCLUSION: Optimistic beliefs are differently beneficial for physical health dependent on the controllability of chronic disease. Unrealistic beliefs are helpful when patients are confronted with moderately to largely uncontrollable disease where self-care options are limited, in contrast to positive efficacy expectancies that are helpful when patients deal with largely controllable disease where self-care is required.

Journal Article↗

PubMed2000

Sitting biomechanics, part II: optimal car driver's seat and optimal driver's spinal model.

BACKGROUND: Driving has been associated with signs and symptoms caused by vibrations. Sitting causes the pelvis to rotate backwards and the lumbar lordosis to reduce. Lumbar support and armrests reduce disc pressure and electromyographically recorded values. However, the ideal driver's seat and an optimal seated spinal model have not been described. OBJECTIVE: To determine an optimal automobile seat and an ideal spinal model of a driver. DATA SOURCES: Information was obtained from peer-reviewed scientific journals and texts, automotive engineering reports, and the National Library of Medicine. CONCLUSION: Driving predisposes vehicle operators to low-back pain and degeneration. The optimal seat would have an adjustable seat back incline of 100 degrees from horizontal, a changeable depth of seat back to front edge of seat bottom, adjustable height, an adjustable seat bottom incline, firm (dense) foam in the seat bottom cushion, horizontally and vertically adjustable lumbar support, adjustable bilateral arm rests, adjustable head restraint with lordosis pad, seat shock absorbers to dampen frequencies in the 1 to 20 Hz range, and linear front-back travel of the seat enabling drivers of all sizes to reach the pedals. The lumbar support should be pulsating in depth to reduce static load. The seat back should be damped to reduce rebounding of the torso in rear-end impacts. The optimal driver's spinal model would be the average Harrison model in a 10 degrees posterior inclining seat back angle.

Automobile Driving↗

PubMed1991

Multiparameter optimizations in micellar liquid chromatography using the iterative regression optimization strategy.

An extension of the iterative regression optimization strategy to multi-parameter optimizations is described and applied to the separation of ionic compounds (amino acids and peptides) by means of micellar liquid chromatography. The parameters examined are the concentration of surfactant, the concentration of 2-propanol and pH. Fairly regular (linear, weakly curved) retention behaviour of the compounds as a function of the parameters results in an efficient optimization using a relatively small number of initial experiments.

Amino Acids↗

PubMed1989

Age-specific optimal diets and optimal foraging tactics: a life-historic approach.

By linking optimal foraging theory and optimal life history theory, we demonstrate that optimal diets, in general, may depend on the individual's age even when everything else remains the same. Older individuals (i.e., individuals with lower reproductive values) are predicted to have diets composed of highly nutritious food types that are possibly dangerous to pursue.

Aging↗

PubMedDate not supplied

Individual fraction optimization vs. first fraction optimization for multichannel applicator vaginal cuff high-dose-rate brachytherapy.

PURPOSE: To challenge the assumption of unchanged interfractional geometry changes in the course of fractionated multichannel vaginal cuff high-dose-rate brachytherapy. METHODS AND MATERIALS: Two methods of treatment planning for delivery of vaginal cuff brachytherapy were compared in 44 applications. Individual fraction optimization (IFO)-performed for the specific geometry of each individual fraction-was compared to first fraction optimization (FFO)-an optimized first fraction, applied unaltered for geometry of subsequent fractions in the same patient. Dose difference to critical organs was expressed as the percentage of the prescribed dose. RESULTS: In the paired analysis for IFO vs. FFO, mean and maximum rectal and bladder doses were similar. However for FFO, an excess of greater than 20% mean dose to either bladder or rectum was observed in 41% of cases. Maximum organ doses were exceeded by 20% in 54.5% of applications. CONCLUSIONS: On the basis of these findings, it can be concluded that IFO may be important to minimize doses to critical structures.

Brachytherapy↗

PubMed2005

QSAR analysis of substituted bis[(acridine-4-carboxamide)propyl]methylamines using optimized block-wise variable combination by particle swarm optimization for partial least squares modeling.

In the current work, we employed optimized block-wise variable combination (OBVC) by particle swarm optimization (PSO) based on partial least squares (PLS) modeling for variable combination and compared it to the traditional methods. It has been demonstrated that the modified PSO is a useful tool for searching optimized variable combination. Quantitative structure-activity relationship (QSAR) model has been formulated for a set of DNA binding topoisomerase (topo) (substituted bis[(acridine-4-carboxamide)propyl]methylamines) on murine Lewis lung carcinoma (LL(c)) cells. The spatial descriptors especially Jurs descriptors play important roles in predicting the compound's inhibitory activity to murine LL(c) cells, and polar interactions are the principal binding strength between compounds and murine LL(c) cells. In addition, rotatable bonds in molecules and molar refractivity of the compounds will markedly affect the compounds' inhibitory activity.

Acridines↗

PubMed2005

Optimal harvesting and optimal vaccination.

Two optimization problems are considered: Harvesting from a structured population with maximal gain subject to the condition of non-extinction, and vaccinating a population with prescribed reduction of the reproduction number of the disease at minimal costs. It is shown that these problems have a similar structure and can be treated by the same mathematical approach. The optimal solutions have a 'two-window' structure: Optimal harvesting and vaccination strategies or policies are concentrated on one or two preferred age classes. The results are first shown for a linear age structure problem and for an epidemic situation at the uninfected state (minimize costs for a given reduction of the reproduction number) and then extended to populations structured by size, to harvesting at Gurtin-MacCamy equilibria and to vaccination at infected equilibria.

Age Distribution↗

PubMed2004

Optimal expansion of water quality monitoring network by fuzzy optimization approach.

River reaches are frequently classified with respect to various mode of water utilization depending on the quantity and quality of water resources available at different location. Monitoring of water quality in a river system must collect both temporal and spatial information for comparison with respect to the preferred situation of a water body based on different scenarios. Designing a technically sound monitoring network, however, needs to identify a suite of significant planning objectives and consider a series of inherent limitations simultaneously. It would rely on applying an advanced systems analysis technique via an integrated simulation-optimization approach to meet the ultimate goal. This article presents an optimal expansion strategy of water quality monitoring stations for fulfilling a long-term monitoring mission under an uncertain environment. The planning objectives considered in this analysis are to increase the protection degree in the proximity of the river system with higher population density, to enhance the detection capability for lower compliance areas, to promote the detection sensitivity by better deployment and installation of monitoring stations, to reflect the levels of utilization potential of water body at different locations, and to monitor the essential water quality in the upper stream areas of all water intakes. The constraint set contains the limitations of budget, equity implication, and the detection sensitivity in the water environment. A fuzzy multi-objective evaluation framework that reflects the uncertainty embedded in decision making is designed for postulating and analyzing the underlying principles of optimal expansion strategy of monitoring network. The case study being organized in South Taiwan demonstrates a set of more robust and flexible expansion alternatives in terms of spatial priority. Such an approach uniquely indicates the preference order of each candidate site to be expanded step-wise whenever the budget limitation is sensitive in the government agencies.

Environmental Monitoring↗

PubMedDate not supplied

D-optimal mixture design: optimization of ternary matrix blends for controlled zero-order drug release from oral dosage forms.

The objective of the present study was to develop a tablet formulation with a zero-order drug release profile based on a balanced blend of three matrix ingredients. To accomplish this goal, a 17-run, three-factor, two-level D-Optimal mixture design was employed to evaluate the effect of Polyox (X1), Carbopol (X2), and lactose (X3) concentrations on the release rate of theophylline from the matrices. Tablets were prepared by direct compression and were subjected to an in vitro dissolution study in phosphate buffer at pH 7.2. Polynomial models were generated for the responses Y4 (percent released in 8 h) and Y6 (similarity factor or f2). Fitted models were used to predict the composition of a formulation that would have a similar dissolution profile to an ideal zero-order release at a rate of 8.33% per hour. When tested, dissolution profile of the optimized formulation was comparable to the reference profile (f2 was 74.2, and n [release exponent] was 0.9). This study demonstrated that a balanced blend of matrix ingredients could be used to attain a zero-order release profile. Optimization was feasible by the application of response surface methodology, which proved efficient in designing controlled-release dosage forms.

Acrylates↗

PubMed2006

Two system-size-resonance behaviors for calcium signaling: for optimal cell size and for optimal network size.

We have studied the collective calcium signaling behavior of an array of coupled N cells, taking into account the internal noises resulting from the small cell size V. The system's performance was characterized by the reciprocal coefficient of variance (RCV) of the calcium spike train. Two system-size resonances were observed, namely, the RCV value shows a clear peak when both N and V are optimal. Therefore, an optimal number of cells of optimal size work the best as a whole.

Animals↗

PubMed2000

Optimal states and almost optimal adaptive measurements for quantum interferometry

We derive the optimal N-photon two-mode input state for obtaining an estimate straight phi of the phase difference between two arms of an interferometer. For an optimal measurement [B. C. Sanders and G. J. Milburn, Phys. Rev. Lett. 75, 2944 (1995)], it yields a variance (Deltastraight phi)(2) approximately pi(2)/N2, compared to O(N-1) or O(N-1/2) for states considered by previous authors. Such a measurement cannot be realized by counting photons in the interferometer outputs. However, we introduce an adaptive measurement scheme that can be thus realized, and show that it yields a variance in straight phi very close to that from an optimal measurement.

Journal Article↗

PubMedDate not supplied

A primer on dynamic optimization and optimal control in pharmacoeconomics.

Pharmacoeconomic analyses employ a wide range of techniques and methods to help societies allocate scarce health-care resources wisely, fairly, and efficiently. Techniques such as dynamic optimization and optimal control, however, have yet to be exploited by this field. Although control theory has a long history in mathematical biology and disease management, its application to economic costs in these disciplines has not yet been explored. Pharmacoeconomics therefore may offer a particularly promising starting point because of the emphasis this field places on the economic perspective. Although challenges may exist to implementing these techniques in practice (at least in some settings), there will nevertheless be value to considering the dynamic perspective these techniques offer, which requires thinking more critically about the optimal allocation of scare health-care resources over time. Therefore, our article serves as a primer to introduce this dynamic perspective from an economic standpoint within the context of two examples of treating of hyperlipidemia.

Cost Control↗

PubMed2004

Exogenous and endogenous postprandial lipid abnormalities in type 2 diabetic patients with optimal blood glucose control and optimal fasting triglyceride levels.

The aim of this study was to evaluate exogenous and endogenous lipoprotein responses to a standard fat-rich meal in type 2 diabetic patients with optimal fasting triglyceridemia and optimal blood glucose control. Seven type 2 diabetic patients and five nondiabetic controls (age, 49 +/- 7 and 48 +/- 4 yr; body mass index, 28.3 +/- 3.6 and 25.1 +/- 3.6 kg/m(2); mean +/- SD) were given, after at least 12 h of fasting, a standard fat-rich meal. Before and over the 6 h after the meal, serial blood samples were taken for determination of glucose, insulin, lipids, lipoproteins, apolipoprotein B-48 (apo B-48), apo B-100, free fatty acids, and lipoprotein lipase activity. The main abnormality in the postprandial lipid response of diabetic patients involved large very low density lipoproteins. In these particles, apo B-48, apo B-100, cholesterol, and triglyceride incremental areas were, in fact, significantly higher in diabetics compared with controls [7.08 +/- 2.65 vs. 1.17 +/- 0.88 mg/liter.h, 65.5 +/- 11.5 vs. 12.4 +/- 1.77 mg/liter.h, 29.7 +/- 3.9 vs. 13.1 +/- 3.1 mg/dl.h (0.77 +/- 0.10 vs. 0.34 +/- 0.08 mmol/liter.h), 170 +/- 31 vs. 94 +/- 22 mg/dl.h (1.93 +/- 0.35 vs. 1.06 +/- 0.25 mmol/liter.h)] (all P < 0.05; mean +/- SEM). Postprandial preheparin lipoprotein lipase plasma activity was, if anything, higher in diabetic patients. In conclusion, even with fasting normotriglyceridemia and optimal blood glucose control, type 2 diabetic patients are characterized, in the postprandial period, by a significant increase in large very low density lipoproteins of both endogenous and exogenous origins.

Blood Glucose↗

PubMed1986

[Optimization and optimal control of pharmacokinetics].

In the literature there does not exist many efficient methods for solving identification and optimal control problems in pharmacokinetics. We present a global optimization method for finding the optimum of functions involving several real variables. This technique can be applied to many identification problems. Furthermore a method of successive derivations for the resolution of optimal control problems associated to compartmental modelling is developed.

Humans↗

PubMedDate not supplied

[Means of optimizing light energy conversion in the primary stages of photosynthesis. II. Optimization of the structure of an uniform photosynthetic unit lattice].

The possibility of optimization of the structure of a model photosynthetic unit lattice is analysed. The efficiency of the photosynthetic unit operation is evaluated from the time of excitation energy trapping by reaction centers. The calculations assume a Förster inductive resonance mechanism for energy transfer within light--harvesting antenna and pairwise dipolar interactions. We use the probability matrix method which is adapted to excitation trapping time (but not to excitation jumps number) calculation. It is shown that the specific anisotropy of the distances between antenna molecules (which is in principle possible due to the diskshaped form of chlorophyll molecules) in combination with the optimal spatial arrangement of reaction centers as "well regulated clusters" allows to decrease the time of excitation energy trapping by over an order of magnitude. The requirements for optimization of the structure of a macroscopic photosynthetic unit lattice and the consequences following from them for the in vivo systems are formulated.

Chlorophyll↗

PubMed1981

Optimization of radiotherapy. Some notes on the principles and practice of optimization in cancer treatment and implications for clinical research.

Two methods dominate cancer treatment--one, the traditional best practice, individualized treatment method and two, the a priori determined decision method of the interinstitutional, cooperative, clinical trial. In the first, choices are infinite and can be made at the time of treatment; in the second, choices are finite and are made in advance of treatment on a random basis. Neither method systematically selects, identifies, or formalizes the optimum level of effect in the treatment chosen. Of the two, it can be argued that the first, other things being equal, is more likely to select the optimum treatment. The determination of level of effect for the optimization of cancer treatment requires the generation of dose-response relationships for both benefit and risk and the introduction of benefit and risk considerations and judgements. The clinical trial, as presently constituted, doses not yield this kind of information, it being, generally, of the binary yes or no, better or worse type. The best practice, individualized treatment method can yield, when adequately documented, both a range of dose-response relationships and a variety of benefit and risk considerations. The presentation will be limited to a consideration of a single modality of cancer treatment, radiation therapy, but an analogy with other modalities of cancer treatment will be inferred. Criteria for optimization will be developed and graphic means for its identification and formalization will be demonstrated with examples taken from the radiotherapy literature. The general problem of optimization theory and practice will be discussed; the necessity for its exploration in relation to the increasing complexity of cancer treatment will be developed; and recommendations for clinical research will be made including a proposal for the support of clinics as an alternative to the support of programs.

Dose-Response Relationship, Radiation↗