Effect of irrigation method on transmission to and persistence of Escherichia coli O157:H7 on lettuce

In this study, the transmission of Escherichia coli O157:H7 to lettuce plants through spray and surface irrigation was demonstrated. For all treatments combined, the number of plants testing positive following a single exposure to E. coli O157: H7 through spray irrigation (29 of 32 plants) was larger than the number testing positive following surface irrigation (6 of 32 plants). E. coli O157:H7 persisted on 9 of 11 plants for 20 days following spray irrigation with contaminated water. Immersion of harvested lettuce heads for 1 min in a 200 ppm chlorine solution did not eliminate all E. coli O157:H7 cells. The results of this study suggest that regardless of the irrigation method used, crops can become contaminated; therefore, the irrigation of food crops with water of unknown microbial quality should be avoided.     

Vancomycin dimerization and chiral recognition studied by high-performance liquid chromatography

The retention and separation of D,L-dansylvaline enantiomers (used as test solutes) were investigated using silica gel as stationary phase and vancomycin as chiral mobile-phase additive. A retention model was developed to describe the mechanistic aspects of the interaction between solute and vancomycin in the chromatographic system. It considered the formation of vancomycin dimers both "free" in the mobile phase and adsorbed on silica. By fitting the model equation to experimental data, it appeared clearly that the approach taking into account the vancomycin dimerization described accurately the retention behavior of the compounds. The examination of the model equation parameters showed that the glycopeptide dimerization increased the enantioselectivity by a factor of approximately 3.7. This study demonstrated the preponderant role of the vancomycin dimerization on the chiral recognition process of D,L-dansylvaline. Also, an additional analysis on a vancomycin chiral stationary phase indicated that the addition of vancomycin in the mobile phase promoted a greater enantioselectivity mediated by the formation of dimers in the stationary phase.     

A fiber-optic fluorescence sensor for lithium ion in acetonitrile

A novel fiber-optic fluorescence sensor based on a controlled-release reagent for the determination of lithium ion in organic solvents is proposed. The fluorogenic indicator 2-(2-hydroxyphenyl)benzoxazole is contained in a mini-polyethylene tube as the reagent reservoir and is brought into contact with the analyte solution by diffusion across a poly(vinyl chloride) (PVC) membrane to form a strongly fluorescent complex at the membrane/solution interface. The fluorescence signals produced are measured via two joined optical fibers positioned closely to the backside of the PVC membrane for light illumination and collection. The sensor is useful for measuring Li+ at concentrations in acetonitrile ranging from 1.0 x 10(-6) to 1.0 x 10(-2) M with a detection limit of 3.0 x 10(-7) M. The steady-state response can be reached within seconds, and the signal changes are fully reversible. The sensor shows minimal interference effects from other alkali metal and alkaline earth metal cations and has good stability and durability when stored in acetonitrile solutions.     

The intriguing role of spanish language vocabulary knowledge in predicting English reading comprehension.

This study explored a holistic model of English reading comprehension among a sample of 135 Spanish-English bilingual Latina and Latino 4th-grade students This model took into account Spanish language reading skills and language of initial literacy instruction. Controlling for language of instruction, English decoding skill, and English oral language proficiency, the authors explored the effects of Spanish language alphabetic knowledge, fluency, vocabulary knowledge, and listening comprehension on English reading comprehension. Results revealed a significant main effect for Spanish vocabulary knowledge and an interaction between Spanish vocabulary and English fluency, such that faster English readers benefited more from Spanish vocabulary knowledge than their less fluent counterparts. This study demonstrates the existence of literary skills transfer from the 1st to the 2nd language, as well as limits on such transfer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Forms of Intersubjectivity in Infant Research and Adult Attachment.

Reviews the book, Forms of Intersubjectivity in Infant Research and Adult Attachment by Beatrice Beebe, Steven Knoblauch, Judith Rustin, and Dorienne Sorter (2005). In this book, the authors use their 10 years of collaborative work to produce an in-depth and well-constructed discussion of verbal and nonverbal forms of intersubjectivity as observed in the treatment setting and as evidenced by data generated from more mainstream child development studies. They move beyond the lack of integration between these related though often dramatically disconnected disciplines and build on infant researchers' understanding of "prereflective" caregiver-child interactions to offer a new theory of intersubjectivity that enhances our understanding of the clinical interaction with adult patients. This book is not for those therapists who are interested in learning well-specified, new interventions to use in their psychotherapy practice. It is also not suggested for those clinicians who do not have some background in psychoanalytic theory and practice. It is, however, recommended for those clinicians who work psychodynamically and are interested in developing their awareness of the nonverbal aspects of treatment and the co-construction of the therapeutic encounter. This book would also be useful to those in the field of psychotherapy research as it poses new questions about the nature of the therapeutic process and suggests the importance of examining the role that implicit, nonverbal interactions play in psychotherapy. Beebe, Knoblauch, Rustin, and Sorter's book is well constructed, persuasively argued, and highly recommended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

产品设计对改进产品生命终期的影响

本研究的主要目标是在鼓励创造性思维的同时，建立一个结构化方法用于阐明产品生命周期策略。当前提倡采用适用于大多数产品的通用规则。联系“通用性”原则，与“放之四海皆准”的方法相比，本研究找出了影响产品生命终期的主要因素。研究结果可分为两个核心部分。第一，根据产品的技术特性，该方法论确定了合理的产品生命终期策略第二，为了评估和验证该方法，将产品生命终期策略的分类和当前工业实践进行了对比，开发的产品生命终期设计顾问(ELDA)软件，指导生产商确定适合的产品生命终期策略。对产品生命终期进行分类的能力使得设计者能够重新设计对环境负荷较小产品。这篇文章为设计者和生产管理者提供了合适的产品生命终期策略。通过更深入的理解相应产品的生命终期策略，本文的研究结果能够帮助设计者开发适合他们情况的、系统的产品生命终期策略。通过技术革新或者价值链的改进，将ELDA的结果运用于生命终期改善。     

Parent psychopathology, parenting, and child internalizing problems in substance-abusing families.

A structural model accounting for child internalizing problems in substance-abusing families was tested. Parents receiving substance abuse treatment (N = 242) completed forms about children between the ages of 6 and 18 who resided in their home. The effects of parent gender, child gender, and child age were controlled. Negative parenting was examined as a mediator between parent internalizing and externalizing problems and child anxiety and affective problems using path analysis. Negative parenting mediated relations only between parent internalizing problems and child affective problems. High-positive involvement moderated relations between parent externalizing problems and child internalizing problems. Relations between parent externalizing problems and child anxiety and affective problems were significant only among families in which high-positive involvement was present. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of fractional delay systems of retarded and neutral type

This paper analyses several properties linked to the robust control of fractional differential systems with delays. The BIBO stability of both retarded and neutral fractional delay systems is related to the location of their poles. In the particular case of retarded systems, we give some properties of the poles of the system and the singular values of its Hankel operator.     

Structure of the M{alpha}2-3 toxin {alpha} antibody-antigen complex: combination of modelling with functional mapping experimental results

Modelled structures of the acetylcholine receptor-mimickingantibody, M2-3, both free and bound to its antigen, toxin ,are assessed in the light of new experimental mutational datafrom functional mapping of the paratopic region of M2-3. Theexperimental results are consistent with the previously-predictedstructure of the free antibody, and also demonstrate that structuralparticularities of the M2-3 combining site that were identifiedin the models play a role in the protein association. The modelledconformations of the hypervariable loops are discussed in thecontext of recent new data and analyses. The new mutationaldata allow several previously-considered modelled structuresof the complex to be rejected. Two quite similar models nowremain.