The Paradoxical Effects of Blockchain Technology on Social Networking Practices

Blockchain technology is a promising, yet not well understood, enabler of large-scale societal and economic change. For instance, blockchain makes it possible for users to securely and profitably share content on social media platforms. In this study, w

Revealing the Vicious Circle of Disengaged User Acceptance: A SaaS Provider's Perspective

User acceptance tests (UAT) are an integral part of many different software engineering methodologies. In this paper, we examine the influence of UATs on the relationship between users and Software-as-a-Service (SaaS) applications, which are continuously delivered rather than rolled out during a one-off signoff process. Based on an exploratory qualitative field study at a multinational SaaS provider in Denmark, we show that UATs often address the wrong problem in that positive user acceptance may actually indicate a negative user experience. Hence, SaaS providers should be careful not to rest on what we term disengaged user acceptance. Instead, we outline an approach that purposefully queries users for ambivalent emotions that evoke constructive criticism, in order to facilitate a discourse that favors the continuous innovation of a SaaS system. We discuss theoretical and practical implications of our approach for the study of user engagement in testing SaaS applications

Contested elections before the general court of Massachusetts, 1780-1942

Thesis (M.A.)--Boston University, 1949. This item was digitized by the Internet Archive

Assay of enzymes of clinical and biological significance by an interference free coline biosensor

Choline (Ch) is widely distributed in nature since it is an important source of methyl groups, an essential component of certain lipids and, in the nervous tissue of most organisms, a precursor of acetylcholine, which is a major neurotransmitter. Ch can be selectively determined by detection of H2O2 generated by the choline oxidase (ChO) catalyzed reaction. Several amperometric methods, based on the this reaction, have been developed in order to detect choline or species which determine choline release such as cholinesterase (ChE), acetylcholine (AChE), phospholipase D (PLD) and choline containing phospholipids. Measurement of serum ChE is important to assess liver function and monitor excessive exposure to organophosphorus insecticides[1]. It is also useful in predicting susceptibility to prolonged apnea after the administration of succinylcholine[2]. There are many methods for the measurement of cholinesterase activity including manometric, titrimetric and photometric procedures. The reference procedure for ChE assay is the Ellman colorimetric method[3] in which haemoglobin and glutathione present in erythrocytes act as interfering substances. PLD is widespread in plants as well as in some microorganisms and mammalian tissues and can have multiple effects and significance on cellular functions, such as receptor signal transduction[4] and an important role in postharvest metabolism of plant tissue. Methods published[5] for PLD activity assay have mainly involved the determination of choline by bromothymol blu or by synthetic substrates of PLD. Titrimetric or pH-stat techniques have been described as well as radioassay procedure which is the fastest and most sensitive method but it requires the use of expensive and potentially health hazardous radiolabeled phospholipids. The fundamental role covered by ChE and PLD in clinical and biological fields justifies the increasing interest in developing assay methodologies able to assure sensitivity, accuracy without requiring expensive instrumentation or long procedure time. In this context amperometric biosensors based on ChO play a surely innovative and quite promising role. The techniques reported for immobilizing ChO on the electrode surface are quite laborious. Covalent immobilization on nylon net[6], often coupled to multimembranes assembly[7] in order to preserve the electrode from interference and fouling, besides being complex and time consuming, can cause a certain slowing down of the sensor response. On the contrary a fast response time is an essential requirement for the on line monitoring of analytes in real samples. The aim of the present study was to develop a choline amperometric biosensor easier to realize moreover assuring high enzyme stability, fast response time, anti-interferent and anti-fouling properties. This goal has been reached in our laboratory immobilizing choline oxidase by co-crosslinking on a platinum electrode previously modified by an overoxidized polypyrrole film. Such an immobilization procedure, already reported in the case of a bienzymic sensor based on choline oxidase and acetylcholinesterase co-immobilization on a platinum electrode[8,9], allowed to obtain an immobilized enzyme-layer characterized by high biocomponent stability and good mechanical properties. Moreover the employment of a bilayer made of co-crosslinked choline oxidase and overoxidised polypyrrole assures notable permselectivity[10] allowing the rejection of interferents usually present in real matrices. Such a Ch biosensor, being interference free, has been employed to assay ChE and PLD in real matrices. In order to optimize the sensor response towards the enzyme to be assayed, the influence of experimental variables such as pH of buffer solution, rotation rate of the electrode and the substrate concentration has been studied. The present method, upon optimization, allowed wide linear range up to 0.600 UI/ml in the case of serum ChE (referred to acetylcholine as enzyme substrate) and to 0.33 UI/ml in the case of PLD. Moreover it revealed suitable for assay ChE in serum samples and PLD in plant crude extracts at activities value respectively down to 5x10-4 UI/ml and to 8x10-5 UI/ml. [1] E. Silk, J. King, M. Whittaker, Ann. Clin. Biochem. 16 (1979) 57 [2] A. Dietz, HM Rubinstein, T. Lubrano, Clin. Chem. 19 (1973) 1309 [3] G. L. Ellman et al. Biochem.Pharmacol. 7 (1961) 88-95 [4] J. H. Exton J. Biol. Chem. 272 (1997) 15579 [5] A. J. Morris, A. M. Frohman, J. Engebrecht, Analytical Biochemistry 252 (1997) 1 [6] E. Vrbovà, I. Kroupovà, O. Valentovà, Z. Novotnnà, J. Kas, Analytica Chimica Acta 280 (1993) 43 [7] G. Palleschi, M. Lavagnini, D. Moscone, R. Pilloton, D. D’Ottavio, M. E. Evangelisti Biosensors & Bioelectronics 5 (1990) 27 [8] A. Guerrieri, G.E. De Benedetto, F.Palmisano, P.G. Zambonin, Analyst 120 (1995) 2731 [9] A. Guerrieri, F. Palmisano, Anal. Chem. 73 (2001) 2875 [10] A. Guerrieri, G. E. De Benedetto, F. Palmisano, P. G. Zambonin, Biosensors & Bioelectronics 13 (1) (1998) 10

A Crosstalk- and Interferent-Free Dual Electrode Amperometric Biosensor for the Simultaneous Determination of Choline and Phosphocholine

Choline (Ch) and phosphocholine (PCh) levels in tissues are associated to tissue growth and so to carcinogenesis. Till now, only highly sophisticated and expensive techniques like those based on NMR spectroscopy or GC/LC- high resolution mass spectrometry permitted Ch and PCh analysis but very few of them were capable of a simultaneous determination of these analytes. Thus, a never reported before amperometric biosensor for PCh analysis based on choline oxidase and alkaline phosphatase co-immobilized onto a Pt electrode by co-crosslinking has been developed. Coupling the developed biosensor with a parallel sensor but specific to Ch, a crosstalk-free dual electrode biosensor was also developed, permitting the simultaneous determination of Ch and PCh in flow injection analysis. This novel sensing device performed remarkably in terms of sensitivity, linear range, and limit of detection so to exceed in most cases the more complex analytical instrumentations. Further, electrode modification by overoxidized polypyrrole permitted the development of a fouling- and interferent-free dual electrode biosensor which appeared promising for the simultaneous determination of Ch and PCh in a real sample

Electrophoretic protein deposition: a new enzyme immobilization method for the development of amperometric biosensors

Electrodeposition is an enzyme immobilization method based on the well-known electrophoretic phenomena of proteins under the influence of an electrical field. In the original method, the enzyme is mixed to a collagen dispersion at a pH value different from their isoelectric points to form macromolecular complexes which migrate to, and deposit on, an electrode surface held at an appropriate electric potential. In spite of the interest of such a method, quite similar to the enzyme entrapment in electrosynthesized polymers, the so-called "electrochemical immobilization", up to now few papers have been devoted on this subject. These studies do not deal with the understanding of both chemical and electrochemical processes involved in protein electrodeposition, which are particularly significant for the proper development of biosensors. For example, a study of a suitable electrochemical technique, able to control the protein deposition while minimizing the undesirable but collateral faradaic processes (i.e. O2 evolution), cannot be found in the relevant literature. More important, the realization of an useful biosensor, free of interference and fouling problems (which arise in real matrices analysis) has not yet been achieved with this approach. The electrodeposition method, herewith called "electrophoretic protein deposition" (EPD), has been investigated in our laboratory with the aim to develop a novel approach in amperometric biosensor realization. The influence of some chemical and electrochemical parameters on the protein deposition has been studied with several electrochemical methodologies. Galvanodynamic and potentiodynamic techniques have been compared in terms of membrane quality, thickness and spatial control of protein deposition. An electrochemical quartz crystal microbalance study permitted further insights about the growth of proteic deposit on the electrode surface. The enzyme electrodes so obtained have been further characterized to realize the feasibility of EPD procedure for the development of an useful biosensor. In this respect, the realization of amperometric biosensors using the hybrid approach has been drawn out to this novel enzyme immobilization procedure. In particular, EPD of co-crosslinked bovine serum albumin/glucose oxidase membranes coupled with electrosynthesized non-conducting films of poly-2-naphthol or poly-o-aminophenol permitted the realization of glucose biosensors with anti-interference and anti-fouling performances so interesting to assure a future employment for real sample analysis

Six Inversion Strategies for Avoiding Rejection in Academic Publishing: Lessons from the IS Discipline

The publication process in many academic disciplines, including in Information Systems (IS), can seem arduous and unpredictable, particularly for early career researchers. While the literature offers plentiful guidance on how to pursue a paper acceptance, this paper offers a crisp summary of common mistakes that lead to rejection and how to avoid them. We provide six actionable inversion strategies for avoiding common mistakes that often lead to paper rejection. Namely, when preparing a paper, we recommend you (1) abstain from methodological promiscuity and (2) never overclaim (but try not to underclaim either); When submitting a paper, it is a good idea to (3) steer clear of bootlicking and (3) avoid sloppiness; And, after receiving the reviews, you should (5) forego belligerence, and (6) stop flogging a dead horse. These inversion strategies can help early career researchers better navigate the review process, increasing the chances of their papers maturing, and helping to avoid mistakes that lower the chance of publishing in high quality IS journals