DNA-oligonucleotide encapsulating liposomes as a secondary signal amplification means

A novel liposome-based signal amplification system was developed by encapsulating DNA oligonucleotides within antibody-tagged liposomes and subsequently detecting the oligonucleotide with dye-encapsulating liposomes for double signal enhancement. In this sandwich immunoassay, the model analyte, protective antigen protein from B. anthracis, was captured by one set of antibodies immobilized in microtiter plate wells and detected using a second antibody conjugated to oligonucleotide-encapsulating liposomes. Bound liposomes were lysed releasing the encapsulated fluorescein-tagged DNA 25-mer probe, which was then permitted to hybridize with its complementary sequence immobilized in a second plate. Finally, the amount of oligonucleotide was detected through the addition of anti-fluorescein antibody tagged dye-encapsulating liposomes. These secondary liposomes allowed for a approximately 400x lower LOD than detection of the fluorescein-labeled probe alone. Several aspects were investigated, including the encapsulation of various oligonucleotide concentrations within liposomes; oligonucleotide hybridization times and buffers; degree of anti-fluorescein antibody coverage on the liposomes; and immobilized anti-protective antigen antibody concentration. We found that the encapsulation efficiency increased with the starting oligonucleotide concentration. As many as 4000 DNA 25-mers were successfully entrapped in the liposome, and minimal leakage was observed over the course of 8 months. When used in the sandwich immunoassay, a limit of detection of 4.1 ng/mL protective antigen was observed with an upper limit of 5000 ng/mL. Due to the endless combination of DNA oligonucleotide sequences, this assay lends itself perfectly for multiplexing on the order of tens to hundreds of analytes.     

Yes, cavalier attitudes can have pernicious consequences.

Responds to the comments by J. J. Krueger, K. D. Vohs, and R. F. Baumeister (see record 2007-19520-015) on the current authors' original article, "Do people's self-views matter? Self-concept and self-esteem in everyday life" (see record 2007-01685-002). Krueger et al brought up many points with which the current authors agree. Nevertheless, as Krueger et al noted these points of agreement, the current authors focus instead on several points of continued disagreement. In addition, the current authors comment on a few new twists that Krueger et al have added to their argument. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhancing third-grade student' mathematical problem solving with self-regulated learning strategies.

The authors assessed the contribution of self-regulated learning strategies (SRL), when combined with problem-solving transfer instruction (L. S. Fuchs et al., 2003), on 3rd-graders' mathematical problem solving. SRL incorporated goal setting and self-evaluation. Problem-solving transfer instruction taught problem-solution methods, the meaning of transfer, and 4 superficial-problem features that change a problem without altering its type or solution; it also prompted metacognitive awareness to transfer. The authors contrasted the effectiveness of transfer plus SRL to the transfer treatment alone and to teacher-designed instruction. Twenty-four 3rd-grade teachers, with 395 students, were assigned randomly to conditions. Treatments were conducted for 16 weeks. Students were pre- and posttested on problem-solving tests and responded to a posttreatment questionnaire tapping self-regulation processes. SRL positively affected performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leukemic phase of mantle cell lymphoma presenting as anemia: diagnosis by combining flow cytometry and cytomorphology

We report a case of mantle cell lymphoma in leukemic phase, which was diagnosed by a bone marrow biopsy performed as part of a workup for chronic anemia in a patient without lymphadenopathy. The patient, a 79-year-old man with diabetes mellitus, hypertension, chronic renal failure, congestive heart failure, and atherosclerosis, presented with claudication. On admission, he also had an 8-month history of anemia, during which time he experienced a 18-kg weight loss. On presentation, the patient had normal vital signs, anemia, leukocytosis (as well as an absolute lymphocytosis), and splenomegaly; as mentioned, lymphadenopathy was absent. A bone marrow biopsy showed an increase in small to intermediate-sized, slightly irregular lymphocytes in interstitial nodules. Flow cytometric immunophenotyping of the bone marrow identified a monoclonal population of cells, representing 25% of cells within the bone marrow, with expression of CD19, CD20, immunoglobulin M/D, lambda light chain, HLA-DR, and CD5; reactions for CD10 and CD23 were absent. Based on morphologic and immunophenotypic analysis of the bone marrow, as well as morphologic review of the peripheral blood smear, a diagnosis of mantle cell lymphoma involving the bone marrow and in leukemic phase was made. Subsequent polymerase chain reaction analysis of DNA from peripheral blood identified a population of cells with the bcl-1 rearrangement. This case is unique in that the diagnosis of mantle cell lymphoma was made without lymph node or spleen analysis and the patient, although exhibiting bone marrow and peripheral blood involvement by mantle cell lymphoma at presentation, did not have lymphadenopathy.     

Large-periodicity two-dimensional crystals by cocrystallization

Patterning surfaces with features on the low end of the nanoscale can efficiently be accomplished with physisorbed monolayers. Here, cocrystallization is revealed as a powerful approach toward dramatically increasing the periodicity of surface features and expanding the length scale on which these patterns can form. By variation of the ratio of adsorbates in solution, surface composition can be controlled such that features on the length scale of several molecules are obtained, offering a facile approach to surface nanopatterning.     

Driving anger, sensation seeking, impulsiveness, and boredom proneness in the prediction of unsafe driving

The present study investigated the potential contribution of sensation seeking, impulsiveness, and boredom proneness to driving anger in the prediction of aggressive and risky driving. Two hundred and twenty-four college student participants completed measures of trait driving anger, aggressive and risky driving, driving anger expression, sensation seeking, impulsiveness, and boredom proneness. Findings provided additional support for the utility of the Driving Anger Scale (DAS; Deffenbacher, J.L., Oetting, E.R., Lynch, R.S., Development of a driving anger scale, Psychological Reports, 74, 1994, 83-91.) in predicting unsafe driving. In addition, hierarchical multiple regression analyses demonstrated that sensation seeking, impulsiveness, and boredom proneness provided incremental improvements beyond the DAS in the prediction of crash-related conditions, aggressive driving, risky driving, and driving anger expression. Results support the use of multiple predictors in understanding unsafe driving behavior.     

Lapse-induced surges in craving influence relapse in adult smokers: An experimental investigation.

Objectives: Nearly all smokers who lapse experience a full-blown relapse, but the mediating mechanisms that contribute to this relationship are not well understood. A better understanding of these mechanisms would help to advance more effective relapse prevention treatments for smokers. The purpose of this study is to experimentally evaluate the effects of a programmed smoking lapse on smoking relapse and the effects of postlapse changes in craving on relapse. Method: Adult smokers (n = 63) who quit smoking with a brief cognitive–behavioral intervention and self-help materials were randomly assigned to one of two experimental conditions after 48 h of abstinence: No lapse (a no-smoking control/30-min waiting period) or lapse (smoking two cigarettes of their favored brand during a 30-min period). All participants were then followed daily for 14 days. Craving and biochemically verified self-reported abstinence were assessed on each follow-up day. Time (days) to relapse (7 consecutive days of smoking) was the main dependent measure. Results: Results of Cox regression analysis revealed that participants in the lapse condition relapsed more quickly than participants in the no-lapse condition (hazard ratio [HR] = 2.12, 95% confidence interval [CI] = [1.03, 4.35]). These effects were attributable, in part, to episodic increases in craving among participants in the lapse condition only (HR = 12.42, 95% CI =[2.00, 77.1]). Conclusions: Previously abstinent smokers who lapse are at risk for increased cigarette cravings and consequently, full-blown relapse. These results have implications for both cognitive–behavioral treatments for relapse prevention and for medications designed to help smokers manage cravings. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Semi-Markov adaptive critic heuristics with application to airline revenue management

The adaptive critic heuristic has been a popular algorithm in reinforcement learning(RL) and approximate dynamic programming(ADP) alike.It is one of the first RL and ADP algorithms.RL and ADP algorithms are particularly useful for solving Markov decision processes(MDPs) that suffer from the curses of dimensionality and modeling.Many real-world problems,however,tend to be semi-Markov decision processes(SMDPs) in which the time spent in each transition of the underlying Markov chains is itself a random variable.Unfortunately for the average reward case,unlike the discounted reward case,the MDP does not have an easy extension to the SMDP.Examples of SMDPs can be found in the area of supply chain management,maintenance management,and airline revenue management.In this paper,we propose an adaptive critic heuristic for the SMDP under the long-run average reward criterion.We present the convergence analysis of the algorithm which shows that under certain mild conditions,which can be ensured within a simulator,the algorithm converges to an optimal solution with probability 1.We test the algorithm extensively on a problem of airline revenue management in which the manager has to set prices for airline tickets over the booking horizon.The problem has a large scale,suffering from the curse of dimensionality,and hence it is difficult to solve it via classical methods of dynamic programming.Our numerical results are encouraging and show that the algorithm outperforms an existing heuristic used widely in the airline industry.