Layer by Layer Assembly of a Biocatalytic Packaging Film: Lactase covalently Bound to Low‐Density Polyethylene

Active packaging is utilized to overcome limitations of traditional processing to enhance the health, safety, economics, and shelf life of foods. Active packaging employs active components to interact with food constituents to give a desired effect. Herein we describe the development of an active package in which lactase is covalently attached to low‐density polyethylene (LDPE) for in‐package production of lactose‐free dairy products. The specific goal of this work is to increase the total protein content loading onto LDPE using layer by layer (LbL) deposition, alternating polyethylenimine, glutaraldehyde (GL), and lactase, to enhance the overall activity of covalently attached lactase. The films were successfully oxidized via ultraviolet light, functionalized with polyethylenimine and glutaraldehyde, and layered with immobilized purified lactase. The total protein content increased with each additional layer of conjugated lactase, the 5‐layer sample reaching up to 1.3 μg/cm². However, the increase in total protein did not lend to an increase in overall lactase activity. Calculated apparent K_m indicated the affinity of immobilized lactase to substrate remains unchanged when compared to free lactase. Calculated apparent turnover numbers (k_cat) showed with each layer of attached lactase, a decrease in substrate turnover was experienced when compared to free lactase; with a decrease from 128.43 to 4.76 s^?1 for a 5‐layer conjugation. Our results indicate that while LbL attachment of lactase to LDPE successfully increases total protein mass of the bulk material, the adverse impact in enzyme efficiency may limit the application of LbL immobilization chemistry for bioactive packaging use.     

The origins of individual differences in adjective check list scores.

Genetic and environmental contributions to individual differences in Adjective Check List (ACL) scores were estimated in a study of 61 pairs of identical (MZ) and fraternal (DZ) twin girls of grade-school age. Comparisons of the intraclass correlation coefficients of MZ and DZ groups for each of the ACL scales showed genetic contributions to 9 scales and systematic environmental contributions to 7 scales. The proportions of genetic and environmental variance are discussed in the context of other research findings, and the problems of scale validity in this population are examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The rights and responsibilities of the social scientist.

Replies to C. W. Oden and W. S. MacDonald's (1978) critique of S. Scarr and R. Weinberg's (see record 1977-07996-001) article concerning transracial adoption. Three issues raised by Oden and MacDonald are addressed: (1) methodological issues, (2) explicit and implicit implications of the results, and (3) the alleged benefits of editorial censorship of scientific reports. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactive computer program for the selection of interference fits

A procedure and an interactive computer program that allow the computer-aided selection of standard manufacturing limits for interference fit joints are presented in detail. The mathematical model describing the problem is outlined together with the algorithms developed for its solution. The relative merits of the computer-aided selection compared with existing manual methods are discussed. A numerical example is provided to demonstrate the capabilities of the proposed computer program.     

Continuous manufacturing of reentrant structures via roll-to-roll process

Reentrant structures have been deemed necessary for repelling low-surface-tension liquids. In this article, a novel manufacturing methodology using the roll-to-roll process to enable continuous manufacturing of reentrant structures over large areas on a polymeric film was demonstrated. A two-stage process, composed of embossing followed by post-compression, allowed the fabrication of reentrant structures, which cannot be easily fabricated using other processes over large areas in a continuous manner. The treatment of the reentrant surface structures with an additional coating of 1H,1H,2H,2H-perfluorooctyltrichlorosilane layer provided liquid repellency with contact angles of 155 and 140°, respectively, for water (Y_lv = 72 mN m⁻¹) and diiodomethane (Y_lv = 50 mN m⁻¹). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46980.     

Effects of display method,number of message lines,and text colour on Chinese comprehension and subjective preferences for an LED display

This study investigated the effects of display method, number of message lines and text colour on comprehension performance and subjective preferences for reading Chinese on a light‐emitting diode display. The factors and levels studied were: two text display methods (rapid serial visual presentation ‘rapid serial visual presentation (RSVP)’ and paged view scrolling), four numbers of message lines displayed at a time (one to four lines) and three text colours (amber, green and red). The RSVP method resulted in higher comprehension scores than the paged view scrolling method, and the green text produced better comprehension score than amber or red. However, the paged view scrolling received better subjective evaluation ratings than the RSVP method. A multiline display was found to be superior to a single‐line display for both comprehension scores and subjective evaluations. The results here provide useful ergonomics recommendations for choice of appropriate display method and format setting for presenting Chinese messages on light‐emitting diode displays.     

Intelligent Grasping with the Robotic Opposable Thumb

Recent advances in the field of grasp planning have used heuristics, dimensionality reduction, machine learning, and haptic feedback, with a high degree of success, to plan grasps for simple grippers and/or simple object geometry. We look at applying some of these techniques to the anthropomorphic Meka gripper. First, dimensionality reduction is attempted. We show that dimensionality reduction does not accurately predict the thumb position. A new algorithm is proposed in which measurements from 2D images are used to classify the thumb opposition angle to one of three positions. The remaining joints employ a reactive torque-control strategy to complete the grasp. The algorithm achieves force closure for 82% of 39 household objects. It is simple, computationally fast, and achieves a success rate that is similar to other contemporary grasp planning algorithms.     

Constructing psychology: Making facts and fables for our times.

Contends, based on a constructionist position on epistemology, that scientific knowledge (and knowledge of all kinds) is a construction of the human mind. Meaning is attributed to sensory data in theoretically guided inventions of "facts." At different times and places, facts invented in one theory become different facts in another. In each generation, psychologists have favored variables that serve loyally within the theoretical boundaries of the scientific wisdom of that time. It is argued that favored variables can blind scientists to other theories and other variables that could compete for favor. What makes theories and facts plausible is examined, and a continuum of persuasion, determined by the contexts of the theorists is proposed. Contemporary research on lead exposure and on parent–child interaction are examined as examples of facts that can become different facts in other theories. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Introduction to the special issue.

Introduces a special issue of American Psychologist in honor of the International Year of the Child. Themes of the issue include the necessity of studying children's behavior in context, the embeddedness of psychology in social-cultural-historical context, the importance of developmental changes across childhood, and the interplay of knowledge and application. (0 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The design and application of technology-based courses in the mathematics classroom

It is difficult to examine the effectiveness of technology-based courses (TBC) without understanding the design and application in classrooms. There is evidence of disconnects among the theory for designing, the theory used to apply TBCs in classrooms, and the theory used to research and evaluate TBCs [Hickey, D. T. (1997). Motivation and contemporary socio-constructivist instructional perspectives. Educational Psychologist, 32(3), 175–193]. Comments provided by administrators, teachers and students may lead researchers to determine whether or not the original TBC course goals have been attained. In this paper, we first discuss examples of theoretical disconnects found in other technology-based research [Aleven, V. E., Stahl, E., Schworm, S., Fischer, F., & Wallace, R. (2003). Help seeking and help design in interactive learning environments. Review of Educational Research, 73(3), 277–320; Hickey, D. T., & McCaslin, M. (2001). A comparative, sociocultural analysis of context and motivation. In S. Volet, & S. Järvelä (Eds.), Motivation in learning contexts: Theoretical advances and methodological implications (pp. 33–55). Elmsford, NY: Pergamon Press]. Then, we describe the course design of the mathematics TBC used in this study, the reasons the principal and the teacher’s believe the software will benefit their mathematics students, and the perceptions of mathematics students regarding the effectiveness of the technology in their classroom. In conclusion, we will discuss how this preliminary qualitative data shaped our future research questions.