A Project Portfolio Management Approach to Tacklingthe Exploration/Exploitation Trade-off

Organizational ambidexterity (OA) is an essen-tial capability for surviving in dynamic business environ-ments that advocates the simultaneous engagement inexploration and exploitation. Over the last decades,knowledge on OA has substantially matured, coveringinsights into antecedents, outcomes, and moderators of OA.However, there is little prescriptive knowledge that offersguidance on how to put OA into practice and to tackle thetrade-off between exploration and exploitation. To addressthis gap, the authors adopt the design science researchparadigm and propose an economic decision model asartifact. The decision model assists organizations inselecting and scheduling exploration and exploitation pro-jects to become ambidextrous in an economically reason-able manner. As for justificatory knowledge, the decisionmodel draws from prescriptive knowledge on projectportfolio management and value-based management, andfrom descriptive knowledge related to OA to structure thefield of action. To evaluate the decision model, its designspecification is discussed against theory-backed designobjectives and with industry experts. The paper alsoinstantiates the decision model as a software prototype andapplies the prototype to a case based on real-world data

Unusual Naturally Occurring Humoral and Cellular Mutated Epitopes of Hepatitis B Virus in a Chronically Infected Argentine Patient with Anti-HBs Antibodies

Serum hepatitis B virus (HBV) DNA was extracted from a chronically infected patient with cocirculation of hepatitis B surface antigen (HBsAg) and anti-HBs antibodies. Direct PCR and clone-derived sequences of the S and overlapped P genes were obtained. DNA sequences and phylogenetic analysis ascribed this isolate to genotype A (serotype adw2). Five of six HBV DNA clones exhibited point mutations inside and outside the major hydrophilic region, while the sixth clone exhibited a genotype A “wild-type” amino acid sequence. Observed replacements included both humoral and/or cellular (major histocompatibility complex class I [MHC-I] and MHC-II) HBV mutated epitopes, such as S45A, P46H, L49H, C107R, T125A, M133K, I152F, P153T, T161S, G185E, A194T, G202R, and I213L. None of these mutants were individually present within a given clone. The I213L replacement was the only one observed in the five clones carrying nonsynonymous mutations in the S gene. Some of the amino acid substitutions are reportedly known to be responsible for the emergence of immune escape mutants. C107R replacement prevents disulfide bonding, thus disrupting the first loop of the HBsAg. Circulation of some of these mutants may represent a potential risk for the community, since neither current hepatitis B vaccines nor hyperimmune hepatitis B immune globulin are effectively prevent the liver disease thereto associated. Moreover, some of the recorded HBsAg variants may influence the accuracy of the results obtained with currently used diagnostic tests

GB Virus C/Hepatitis G Virus Groups and Subgroups: Classification by a Restriction Fragment Length Polymorphism Method Based on Phylogenetic Analysis of the 5′ Untranslated Region

A phylogenetic tree based on 150 5′ untranslated region sequences deposited in GenBank database allowed segregation of the sequences into three major groups, including two subgroups, i.e., 1, 2a, 2b, and 3, supported by bootstrap analysis. Restriction site analysis of these sequences predicted that HinfI and either AatII or AciI could be used for genomic typing with 99.4% accuracy. cDNA sequencing and subsequent alignment of 21 Argentine GB virus C/hepatitis G virus strains confirmed restriction fragment length polymorphism patterns theoretically predicted. This method may be useful for a rapid screening of samples when either epidemiological or transmission studies of this agent are carried out