Editorial/éditorial.

Feedback from colleagues suggests that many psychologists are not aware of the range of articles considered appropriate for publication in the Canadian Psychological Review/Psychologie Canadienne. In an attempt to clarify the purview of the journal, a number of sections have been developed which are designed to reflect the general statement of editorial policy which is carried regularly on the inside front cover. The sections are entitled Reviews, Professional Issues, De Rerum Novarum, and Correspondence. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Application of gel permeation chromatography to the study of shear degradation of polymeric viscosity index improvers used in automotive engine oils

Gel permeation chromatography (g.p.c.) was used to monitor the degradation of polymeric viscosity index improvers in multigrade oils when subjected to mechanical shear using a Kurt Orbahn diesel injector rig. These tests are normally evaluated by measurement of viscosity of the oils before and after shear. For model systems of a base oil containing each of ten viscosity index improvers there is good correlation between viscosity and chromatography results. Tests on a multigrade oil subjected to sonic shear showed that g.p.c. can be used to follow qualitatively the degradation of one polymeric additive in the presence of another.     

Household trials with very small samples predict responses to nutrition counseling intervention

Household trials were conducted to test the acceptability and feasibility of the recommendations to be delivered to the mothers in the context of a randomized intervention implemented in Pelotas, Brazil. A first home visit was paid to assess child health and feeding problems. In a second visit, the mother was encouraged to select one or two recommendations to try out over five days. The last visit was used to assess the mothers' experiences in attempting to implement the recommendations. Nonexclusive breastfeeding, use of the bottle, monotonous diet, and low energy density of foods were the most common problems. The most frequently selected recommendations were those aiming to increase the energy density of foods. Mothers generally reported positive responses to the recommendations. The household trials highlighted the acceptability and feasibility of the planned recommendations and correctly predicted the changes that were successfully implemented by the mothers in the large intervention study.     

Using Dialogue Features to Predict Trouble During Collaborative Learning

A web-based, collaborative distance-learning system that will allow groups of students to interact with each other remotely and with an intelligent electronic agent that will aid them in their learning has the potential for improving on-line learning. The agent would follow the discussion and interact with the participants when it detects learning trouble of some sort, such as confusion about the problem they are working on or a participant who is dominating the discussion or not interacting with the other participants. In order to recognize problems in the dialogue, we investigated conversational elements that can be utilized as predictors for effective and ineffective interaction between human students. These elements can serve as the basis for student and group models. In this paper, we discuss group interaction during collaborative learning, our representation of participant dialogue, and the statistical models we are using to determine the role being played by a participant at any point in the dialogue and the effectiveness of the group. We also describe student and group models that can be built using conversational elements and discuss one set that we built to illustrate their potential value in collaborative learning. An erratum to this article is available at .     

Developing a navigation aid for the frail and visually impaired

This paper describes the development of a new navigational aid for the frail, elderly, and visually impaired person. The users were involved both in the user requirements study and in the evaluation of different prototypes. The results show that the users were able to provide information on their current aid, the use situation, and their preference regarding different solutions, but they had difficulties to provide the detailed answers on technical solutions required by the technical development team. Further, prototype evaluations with users enabled the technical team to understand the users and their use situation.     

Finite element analysis on piezoelectric ring transformer

The use of a piezoelectric ring as transformer is reported and studied in this paper. By using a concentric electrode pattern, a ring-shaped transformer can be designed to operate at its high order extensional modes. Lead zirconate titanate (PZT) ceramic rings with 12.7-mm outer diameter, 5.1-mm inner diameter and 1.2-mm thickness were used to fabricate the prototypes. Three-dimensional (3-D) finite element models are built to study and analyze the vibration characteristics of the piezoelectric transformers (PTs) using higher order modes (>3). The resonant frequencies, mean coupling effect, mode shapes, and other open-circuit characteristics are simulated and compared with experimental measurements. Prototypes of PTs using mode order three and four were fabricated and characterized. Good agreement can be obtained between experimental results and finite element model (FEM) simulations. The dimensions for the PTs using higher order symmetric extensional modes are optimized by FEM. To avoid mode coupling with the thickness mode, the ideal ring thickness has to be less than or equal to 0.6 mm. The ring PT offers advantages of simple structure and small size. It has a good potential in making low cost PT for low-voltage applications.     

Alternative antibody Fab' fragment PEGylation strategies: combination of strong reducing agents, disruption of the interchain disulphide bond and disulphide engineering

Antigen-binding fragments (Fab') of antibodies can be site specifically PEGylated at thiols using cysteine reactive PEG-maleimide conjugates. For therapeutic Fab'-PEG, conjugation with 40 kDa of PEG at a single hinge cysteine has been found to confer appropriate pharmacokinetic properties to enable infrequent dosing. Previous methods have activated the hinge cysteine using mildly reducing conditions in order to retain an intact interchain disulphide. We demonstrate that the final Fab-PEG product does not need to retain the interchain disulphide and also therefore that strongly reducing conditions can be used. This alternative approach results in PEGylation efficiencies of 88 and 94% for human and murine Fab, respectively. It also enables accurate and efficient site-specific multi-PEGylation. The use of the non-thiol reductant tris(2-carboxyethyl) phosphine combined with protein engineering enables us to demonstrate the mono-, di- and tri-PEGylation of Fab fragments with a range of PEG size. We present evidence that PEGylated and unPEGylated Fab' molecules that lack an interchain disulphide bond retain very high levels of chemical and thermal stability and normal performance in PK and efficacy models.     

FPC公司致力于向美国市场供应差异化生活用纸

2015年5月,智利FPC生活用纸公司（FPC）投产了世界上第二台塑纹成形（NTT）卫生纸机。这家公司的管理人员告诉《世界卫生纸》杂志的记者,他们将向美国市场供应高档的优质生活用纸产品。FPC的生活用纸厂位于智利西海岸,于2013年9月破土动工。该公司首席执行官Guillermo Swett说：“因为这一地区经常发生地震,所以有很多相关法规,这样一来工程进度较慢。我们把场地做了防震处理,用了一年半的时间建起了非常坚固的厂房。”     

Cytoskeleton remodelling of confluent epithelial cells cultured on porous substrates

The impact of substrate topography on the morphological and mechanical properties of confluent MDCK-II cells cultured on porous substrates was scrutinized by means of various imaging techniques as well as atomic force microscopy comprising force volume and microrheology measurements. Regardless of the pore size, ranging from 450 to 5500 nm in diameter, cells were able to span the pores. They did not crawl into the holes or grow around the pores. Generally, we found that cells cultured on non-porous surfaces are stiffer, i.e. cortical tension rises from 0.1 to 0.3 mN m⁻¹, and less fluid than cells grown over pores. The mechanical data are corroborated by electron microscopy imaging showing more cytoskeletal filaments on flat samples in comparison to porous ones. By contrast, cellular compliance increases with pore size and cells display a more fluid-like behaviour on larger pores. Interestingly, cells on pores larger than 3500 nm produce thick actin bundles that bridge the pores and thereby strengthen the contact zone of the cells.     

Specialization of tendon mechanical properties results from interfascicular differences

Tendons transfer force from muscle to bone. Specific tendons, including the equine superficial digital flexor tendon (SDFT), also store and return energy. For efficient function, energy-storing tendons need to be more extensible than positional tendons such as the common digital extensor tendon (CDET), and when tested in vitro have a lower modulus and failure stress, but a higher failure strain. It is not known how differences in matrix organization contribute to distinct mechanical properties in functionally different tendons. We investigated the properties of whole tendons, tendon fascicles and the fascicular interface in the high-strain energy-storing SDFT and low-strain positional CDET. Fascicles failed at lower stresses and strains than tendons. The SDFT was more extensible than the CDET, but SDFT fascicles failed at lower strains than CDET fascicles, resulting in large differences between tendon and fascicle failure strain in the SDFT. At physiological loads, the stiffness at the fascicular interface was lower in the SDFT samples, enabling a greater fascicle sliding that could account for differences in tendon and fascicle failure strain. Sliding between fascicles prior to fascicle extension in the SDFT may allow the large extensions required in energy-storing tendons while protecting fascicles from damage.