Enzymatic reactions in microdevices

Enzyme reactions conducted in microdevices for diagnostic applications minimize the enzyme usage. In this research, polydimethylsiloxane microdevices were fabricated and used to study the well studied hydrogen peroxide decomposition reaction using bovine liver catalase. Soft lithography techniques were developed to fabricate custom-made microdevices in-house. High resolution photomasks and oxygen plasma treatment followed by baking for 2--3 hours yielded microdevices with vertical walls that did not leak easily. Flow experiments were conducted with free enzyme, enzyme immobilized on microdevice walls, and carrier-free enzyme aggregates. For free enzyme and carrier-free enzyme aggregate reactions, the average reaction rate showed a maxima at ∼80 mmol/L as predicted from macroscale batch experiments. The trend for average reaction rate was consistent with the model series reactor scheme developed. Covalent binding of enzyme to the microdevice wall was not achieved as the enzyme was found to continuously leach from the microdevice walls

Dialogical practices for imagined lines: Listening, Interference, and (non) Straight

Imagined lines are proposed here as a phenomenon found in concepts, mental imagery, and metaphors. This essay has three parts to highlight the multimodality of imagined lines: a video, an audio track, and a written component. The writing introduces practices, frames the artistic works, and describes and considers the breadth of what an imagined line could be. The audio and video works give context to the writing and communicate in their medium the experience of imagined lines that appear in other modes. The body is used here as the starting point for examining its traces and how that helps us to understand ideas like straight, interference, and listening. This essay proposes that a closer examination of imagined lines can bring unrelated topics into proximity. Simultaneously, the work suggests there are benefits when paying attention to incorporating and using imagined lines in our thinking. By bringing what is often unnoticed into our awareness, we can make direct relationships between the intangible and tangible

Cayley Map Embeddings of Complete Graphs With Even Order

German mathematician Claus Michael Ringel used voltage graphs to embed complete graphs onto orientable surfaces such that none of the graph\u27s edges cross each other. Cayley maps do the same whilst being simpler to work with. The goal is to determine the efficiency of Cayley maps in embedding complete graphs onto orientable surfaces. This article focus on complete graphs of even order with an emphasis on graphs whose orders are congruent to 6 modulo 12 and 0 modulo 12. We establish 12 distinct classes that each have their own unique qualities. Through the generalization of a previous technique, we prove a nontrivial bound on the Cayley genus of graphs whose order is congruent to 6 modulo 12. We also show that Cayley maps cannot embed a complete graph onto its optimal genus for 8 out of the 12 classes provided the graph\u27s order is greater than 6

The double edged sword of depersonalization: An examination of depersonalization\u27s role in the police profession

The role of depersonalization is the central focus of this study. A major issue in examining the role of depersonalization is whether the present concept of burnout is an appropriate indicator of bumout for police officers. The commonly accepted conception of burnout is a process of emotional exhaustion that leads to depersonalization, followed by a reduction in work accomplishment. Depersonalization, by this conception, is a symptom of burnout. By definition,depersonalization is the psychological distancing of emotional and psychological trauma in stressful situations—a coping technique. For police officers, depersonalization acts as a shield of emotional armor to maintain a sense of emotional balance. Depersonalization is a way for police officers to psychologically distance themselves from their emotions and feelings in dealing with the trauma of others. Findings, however, have indicated that depersonalization is playing a dual, paradoxical role, for police officers, as both a coping technique and symptom of burnout occurring at the same time. An explanation of depersonalization’s duality is the suppression of emotions and feelings that allows police officers to carry out their assigned duties. Over time the suppression of emotions and feelings builds up to cause an imbalance between depersonalization’s positive and negative attributes. Depersonalization still allows police officers to cope with stress, but the negative attributes intensify the positive attributes to where depersonalization becomes symptomatic of burnout. The imbalance occurs; because of depersonalization’s reciprocating tendency, the movement between coping techniques and symptoms of burnout. Ethnographic interviewing techniques were used to obtain data from six police officers. Domain and componential analysis of the data, and identification of cultural themes, supported the study\u27s hypotheses that depersonalization does play a paradoxical role, is a learned response, and is not a valid indicator of burnout for police officers. The paradoxical roles of depersonalization led to the formulation of enhanced definitions of burnout and depersonalization more appropriate for the police profession. In redefining burnout and depersonalization, a new model of depersonalization was developed. The definitions and model add another dimensional level to depersonalization where tolerance (coping techniques) and callousness (symptoms of burnout) become terms for depersonalization\u27s positive and negative attributes, respectively