Microbial predictors of healing and short-term effect of debridement on the microbiome of chronic wounds.

Chronic wounds represent a large and growing disease burden. Infection and biofilm formation are two of the leading impediments of wound healing, suggesting an important role for the microbiome of these wounds. Debridement is a common and effective treatment for chronic wounds. We analyzed the bacterial content of the wound surface from 20 outpatients with chronic wounds before and immediately after debridement, as well as healthy skin. Given the large variation observed among different wounds, we introduce a Bayesian statistical method that models patient-to-patient variability and identify several genera that were significantly enriched in wounds vs. healthy skin. We found no difference between the microbiome of the original wound surface and that exposed by a single episode of sharp debridement, suggesting that this debridement did not directly alter the wound microbiome. However, we found that aerobes and especially facultative anaerobes were significantly associated with wounds that did not heal within 6 months. The facultative anaerobic genus Enterobacter was significantly associated with lack of healing. The results suggest that an abundance of facultative anaerobes is a negative prognostic factor in the chronic wound microbiome, possibly due to the increased robustness of such communities to different metabolic environments

Non-Natural Nucleotides As Probes For The Mechanism And Fidelity Of DNA Polymerases

DNA is a remarkable macromolecule that functions primarily as the carrier of the genetic information of organisms ranging from viruses to bacteria to eukaryotes. The ability of DNA polymerases to efficiently and accurately replicate genetic material represents one of the most fundamental yet complex biological processes found in nature. The central dogma of DNA polymerization is that the efficiency and fidelity of this biological process is dependent upon proper hydrogen-bonding interactions between an incoming nucleotide and its templating partner. However, the foundation of this dogma has been recently challenged by the demonstration that DNA polymerases can effectively and, in some cases, selectively incorporate non-natural nucleotides lacking classic hydrogen-bonding capabilities into DNA. In this review, we describe the results of several laboratories that have employed a variety of non-natural nucleotide analogs to decipher the molecular mechanism of DNA polymerization. The use of various non-natural nucleotides has lead to the development of several different models that can explain how efficient DNA synthesis can occur in the absence of hydrogen-bonding interactions. These models include the influence of steric fit and shape complementarity, hydrophobicity and solvation energies, base-stacking capabilities, and negative selection as alternatives to rules invoking simple recognition of hydrogen-bonding patterns. Discussions are also provided regarding how the kinetics of primer extension and exonuclease proofreading activities associated with high-fidelity DNA polymerases are influenced by the absence of hydrogen-bonding functional groups exhibited by non-natural nucleotides

Adenosine Triphosphate-Dependent Degradation of A Fluorescent λ N Substrate Mimic by Lon Protease

Escherichia coli Lon exhibits a varying degree of energy requirement toward hydrolysis of different substrates. Efficient degradation of protein substrates requires the binding and hydrolysis of ATP such that the intrinsic ATPase of Lon is enhanced during protein degradation. Degradation of synthetic tetrapeptides, by contrast, is achieved solely by ATP binding with concomitant inhibition of the ATPase activity. In this study, a synthetic peptide (FRETN 89-98), containing residues 89–98 of λ N protein and a fluorescence donor (anthranilamide) and quencher (3-nitrotyrosine), has been examined for ATP-dependent degradation by E. coli and human Lon proteases. The cleavage profile of FRETN 89-98 by E. coli Lon resembles that of λ N degradation. Both the peptide and protein substrates are specifically cleaved between Cys93 and Ser94 with concomitant stimulation of Lon\u27s ATPase activity. Furthermore, the degradation of FRETN 89-98 is supported by ATP and AMPPNP but not ATPγS nor AMPPCP. FRETN 89-98 hydrolysis is eight times more efficient in the presence of 0.5 mM ATP compared to 0.5 mM AMPPNP at 86 μM peptide. The ATP-dependent hydrolysis of FRETN 89-98 displays sigmodial kinetics. The kcat, [S]0.5, and the Hill coefficient of FRETN 89-98 degradation are 3.2 ± 0.3 s−1, 106 ± 21 μM, and 1.6 respectively

Fluorescent Analysis of Translesion DNA Synthesis by Using A Novel, Non-natural Nucleotide Analogue

The replication of damaged DNA is a promutagenic process that can lead to disease development. This report evaluates the dynamics of nucleotide incorporation opposite an abasic site, a commonly formed DNA lesion, by using two fluorescent nucleotide analogues, 2-aminopurine deoxyribose triphosphate (2-APTP) and 5-phenylindole deoxyribose triphosphate (5-PhITP). In both cases, the kinetics of incorporation were compared by using a 32 P-radiolabel extension assay versus a fluorescence-quenching assay. Although 2-APTP is efficiently incorporated opposite a templating nucleobase (thymine), the kinetics for incorporation opposite an abasic site are significantly slower. The lower catalytic efficiency hinders its use as a probe to study translesion DNA synthesis. In contrast, the rate constant for the incorporation of 5-PhITP opposite the DNA lesion is 100-fold faster than that for 2- APTP. Nearly identical kinetic parameters are obtained from fluorescence quenching or the 32 P-radiolabel assay. Surprisingly, distinct differences in the kinetics of 5-PhITP incorporation opposite the DNA lesion are detected when using either bacteriophage T4 DNA polymerase or the Escherichia coli Klenow fragment. These differences suggest that the dynamics of nucleotide incorporation opposite an abasic site are polymerase-dependent. Collectively, these data indicate that 5-PhITP can be used to perform real time analyses of translesion DNA synthesis as well as to functionally probe differences in polymerase function

Hanging with the right crowd: Matching crowdsourcing need to crowd characteristics.

“Crowdsourcing” is the use of large groups of individuals to perform tasks commonly performed by employees or designated agents. Many organizations are attempting to tap into the crowd’s productivity and knowledge, however, we know little about the strategic use of the crowd to meet specific organizational needs. Based on a review of literature, interviews with practitioners, and exploratory case studies, a framework matching organizational need to key characteristics of the crowd is presented. The theoretical contribution of this study is the development of a framework from which researchers can begin to further define key uses and characteristics associated with the phenomenon of crowdsourcing. Its contribution to practice is the development of preliminary guidelines for matching the right crowd to the right job

Returning to the Financial Services Workforce after an Extended Child-Rearing Leave: A Descriptive Study Regarding the Influence of Mentorship on Feelings of Identity and Self-Efficacy

Objectives: To explore the experiences of women in the United States that have returned to the financial services workforce after an extended child-rearing leave and their descriptions of the transition back to the workforce, specifically regarding feelings of self-efficacy and identity and the influence of mentorship. Study design/setting: This study utilized a qualitative descriptive research methodology to capture descriptions through semi-structured interviews and a focus group. Data were gathered by means of extensive one-on-one interviews with women throughout the country and an extensive focus group discussion. All study participants were currently working in the financial services sector after a minimum one-year absence due to child-rearing. Principal findings: The findings imply that multiple factors influence the experiences of women transitioning back into the workforce summarized by five primary themes: 1) challenges, pressure and feelings of identity and self-efficacy, 2) merging personal and professional identities, 3) reinventing professional competencies and self-efficacy, 4) organizational intent to provide connection, goal-setting and path development through mentorship and 5) the unique value of mothers in a historically male-dominated industry and the importance of mentorship to support them. Conclusions: The findings suggest that women returning to the financial services industry after an extended child-rearing find mentorship beneficial by: differentiating and/or merging professional and personal identities, combating imposter syndrome, balancing pressure from both home and work, highlighting value despite resume gap and minimizing self-doubt, heightening sense of belongingness in a historically male-dominated industry and developing a strategic career and development path to meet desired professional goals

Competition in the advanced sale of service capacity

Pre-print of an article accepted for publication in International Journal of Revenue Management; authors' draft dated March 6, 2008; final version available at http://www.inderscience.com

Vowels production by Cantonese-speaking children with cochlear implant

"A dissertation submitted in partial fulfillment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, 30th June, 2010."Includes bibliographical references (p. 28-32).Thesis (B.Sc)--University of Hong Kong, 2010.This study investigated vowels production by Cantonese-speaking children with cochlear implant. Nineteen subjects with cochlear implant age ranged 2;05 to 6;01 years old were compared to 19 hearing children. All participants were required to produce 51 words, covering seven Cantonese monophthongs /a, i, E, O, u, y, J/ and ten Cantonese diphthongs /ui, Oi, ai, iu, Ey, Ai, ou, ei, au, Au/. The production accuracy was compared. Error patterns were investigated by phonological process and acoustic analysis. The production accuracy from cochlear implant subjects with hearing experience less than two years was significantly different than that of hearing children with similar hearing experience. A developmental and universal phonological acquisition process was observed. Developmental phonological rules were found in erroneous production. Articulatory complexity played an important role in vowels acquisition in CI groups. The result demonstrated a positive influence of cochlear implant on vowels production in Cantonese-speaking children.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

Production Cost, Transaction Cost, and Outsourcing Strategy: A Game Theoretic Analysis

This paper presents a game theoretic analysis of the impact of both production and transaction costs on the single-or-multiple source purchasing decision. Both dyadic interactions involving a buyer and a seller, and triadic interactions involving a buyer and two suppliers, are examined to gain a more precise understanding of how small number interactions might influence transaction cost. We show that transaction cost is maximized when a buyer follows a single source strategy and learning specificity is present. Only if a buyer follows a multiple source strategy that splits the supply contract in such a way as to equalize the effects of learning specificity across the suppliers, will transaction cost be maximized and will a buyer be able to appropriate the efficiency gains achieved by its suppliers. Production and transaction costs interact to influence governance decisions. The equilibrium is such that a single (multiple) source strategy is optimal when efficiency gains due to the economies of scale are large (small), but those due to learning specificity are small (large). When both the effects of economies of scale and learning specificity are large, internalization is the optimal strategy

Advanced sale of service capacities: a theoretical analysis of the impact of price sensitivity on pricing and capacity allocations

Pre-print; author's draft dated March 27, 1999Should service firms sell in advance? Using a theoretical approach, we study the optimality of advanced sale of capacity for a monopolistic service firm and examine the impact of market price sensitivity on the optimal price and capacity allocations for advanced sale. We show that when firms undertake advanced sale, capacity utilization and profits are higher even though prices for sale in advance are discounted. In addition, we show that optimal pricing and capacity allocations for advanced sale depend on the expected price sensitivity at the time of consumption. When price sensitivity at the point of consumption is expected to be low (unchanged), it is optimal to allocate more (less) capacity for sale at time of consumption than in advance. Although optimal price and capacity allocations in advanced sale result in excess capacity, we show that having excess capacity is a strategic decision in that it is a dominant strategy