Effects of information processing load in abstinent and nonabstinent smokers' psychomotor task performance.

Recent evidence has indicated that nicotine, the active agent in tobacco, may affect mental abilities of smokers. To better understand the effects of nicotine on central processing, we used a basic chronometric approach to studying information processing. This chronometric approach allowed for the independent examination of nicotine's effects on two theoretically nonoverlapping information-processing stages, stimulus identification and response programming. Two stimulus intensity and four distance traversed conditions were used to affect the stimulus identification and response programming stages, respectively. The 11 subjects completed two experimental sessions (nicotinized and denicotinized), which were conducted 1 week apart. Each experimental session comprised two tests. The first test consisted of abstinent baseline measures, and the second test was administered after subjects smoked an investigator-supplied nicotinized or denicotinized cigarette. Data analysis revealed that the higher intensity stimulus elicited faster reaction times, as did the shorter movement distances, thus confirming successful manipulation of both the stimulus identification and response programming stages of the information-processing model. Furthermore, the significant improvement in reaction-time performance over baseline abstinent levels was consistent despite the manipulations made within the stimulus identification stage of processing, demonstrating that no interaction existed between stimulus intensity and the administration of nicotine. Interestingly, these data provide initial evidence that although nicotine may not affect the programming of very simple movements, it has a more pronounced effect on more complex movements. Although distance traversed had a reliable effect on movement time, nicotine had no observable effect.     

Intensity/time studies of sweetness: Psychophysical evidence for localised concentration of stimulus

Salivary glucose concentrations, following tasting of a 10 ml glucose solution, declined to sub-threshold levels sooner than the elicited persistence of sweetness response. Thus persistence cannot be explained by residual stimulus in the oral fluid. Panellists experience ‘saturation of sweetness intensity’ at lower concentrations of sugar than those which cause ‘saturation of persistence’, which suggests that separate mechanisms are responsible for the intensity and persistence effects. Increases of volume from 10^?2 ml to 1 ml of tasted solution, as well as increases of concentration, cause elevation of both intensity and persistence of sweetness although volume change does not affect intensity of response at low concentrations. These observations can be explained by assuming that the persistence of sweetness response is caused by localised concentrations of stimulus at or near the receptor while intensity is governed by the accessibility of receptors to stimuli at these sites.     

Interactions between phytochemicals from fruits and vegetables: Effects on bioactivities and bioavailability

The combinations of two or more phytochemicals bring about changes in the ultimate biological effects and/or the bioavailability of each component. A number of mixtures of pure bioactive compounds or phytochemical-containing plant extracts provide synergy with regard to antioxidant status, anti-inflammation, anti-cancer and chemoprevention of several oxidative stress and metabolic disorders in vitro. The biological activities of food phytochemicals depend upon their bioaccessibility and bioavailability which can be affected by the presence of other food components including other bioactive constituents. The interactions between phytochemicals during intestinal absorption could result in changes in the bioavailability of the compounds, which in turn affects the intensity of their bioactivities. This paper provides an overview of combined biological effects of phytochemical mixtures derived from fruits and vegetables with a focus on anti-oxidative, anti-inflammatory and anti-carcinogenic activities. The bioavailability impairment or enhancement caused by the co-consumption of dietary phytochemicals is also discussed. Finally, research gaps for future studies on phytochemical interactions are identified.     

Temporal aspects of hedonic and intensity responses

The present study investigated temporal aspects of hedonic responses. The focus was on the hedonic response in itself and on the time-course of the hedonic response as compared to the intensity response. Analogously to time–intensity (TI) scaling, we used temporal scaling for intensity and pleasantness aspects of taste. Twenty four subjects were instructed to focus on and continually rate either the intensity or the pleasantness of three different concentrations of an orange lemonade stimulus in a within-participants design. As was expected, the latency and the time to maximum of the intensity response were shorter than the latency and time to maximum of the hedonic response. Unforeseen, the intensity response lasted longer than the pleasantness response. These results suggest that initially the processing of the intensity and pleasantness aspects is in serial and later on may be in parallel. Our study confirms that, as was suggested by Taylor and Pangborn [Journal of Sensory Studies 4 (1990) 241–247], time–hedonic scaling can be performed.     

How are organic food prices affecting consumer behaviour? A review

This article reviews research on consumer behaviour regarding the price of organic food published from January 2000 to December 2013, in order to identify the current state of research and research gaps. The publications were classified into stimulus–response or stimulus–organism–response paradigm based studies. Organism-internal processes were further divided into ‘affective’, ‘cognitive’ and ‘intentional’ processes. Moreover, for a systematic review the categories ‘price elasticity’, ‘price perception and evaluation’, ‘price knowledge’, and ‘willingness-to-pay’ were built. The majority of studies were based on a stimulus–organism–response paradigm. 20 studies in the sample analysed the price elasticity of demand and reported partly contradictory results. There were no studies on affective processes in the sample. A solid body of knowledge exists on the cognitive processes ‘price perception and evaluation’ while very few studies investigate ‘price knowledge’. The majority of studies were concerned with the willingness-to-pay for organic food and yielded mixed and contradictory results. The explanatory power and conclusiveness of research is impaired by weak sampling techniques (e.g., convenience sampling, sampling at few locations) and data collection methods. The improvement of sampling techniques, the increase of comparability of results and the deepening of analyses is recommended.     

Odor intensity measured by an audio method

A nonverbal, nonnumerical method for measuring odor or taste intensity by means of cross-modal matching with pitch is described. The device with which the measurements are obtained is called an intensometer, and it allows subjects to simply react to intensity without having to describe or quantify what is perceived. The odor intensity function of benzaldehyde, an aromatic substance with a bitter almond odor, was obtained for individuals and for the panel by this method as well as by graphic scaling. A comparison of the two methods revealed better resolution and reliability with the intensometer, which showed no end effects or stimulus range bias.     

Genetic progress in multistage dairy cattle breeding schemes using genetic markers

The aim of this paper was to explore general characteristics of multistage breeding schemes and to evaluate multistage dairy cattle breeding schemes that use information on quantitative trait loci (QTL). Evaluation was either for additional genetic response or for reduction in number of progeny-tested bulls while maintaining the same response. The reduction in response in multistage breeding schemes relative to comparable single-stage breeding schemes (i.e., with the same overall selection intensity and the same amount of information in the final stage of selection) depended on the overall selection intensity, the selection intensity in the various stages of the breeding scheme, and the ratio of the accuracies of selection in the various stages of the breeding scheme. When overall selection intensity was constant, reduction in response increased with increasing selection intensity in the first stage. The decrease in response was highest in schemes with lower overall selection intensity. Reduction in response was limited in schemes with low to average emphasis on first-stage selection, especially if the accuracy of selection in the first stage was relatively high compared with the accuracy in the final stage.Closed nucleus breeding schemes in dairy cattle that use information on QTL were evaluated by deterministic simulation. In the base scheme, the selection index consisted of pedigree information and own performance (dams), or pedigree information and performance of 100 daughters (sires). In alternative breeding schemes, information on a QTL was accounted for by simulating an additional index trait. The fraction of the variance explained by the QTL determined the correlation between the additional index trait and the breeding goal trait. Response in progeny test schemes relative to a base breeding scheme without QTL information ranged from +4.5% (QTL explaining 5% of the additive genetic variance) to +21.2% (QTL explaining 50% of the additive genetic variance). A QTL explaining 5% of the additive genetic variance allowed a 35% reduction in the number of progeny tested bulls, while maintaining genetic response at the level of the base scheme. Genetic progress was up to 31.3% higher for schemes with increased embryo production and selection of embryos based on QTL information. The challenge for breeding organizations is to find the optimum breeding program with regard to additional genetic progress and additional (or reduced) cost.     

Who told you the triangle test was simple?

The effects of response bias, cognitive strategy change and the sequence of tasting are discussed in relation to the triangle test. Theoretical approaches like Thurstonian modelling and Sequential Sensitivity Analysis are reviewed. It is concluded that the triangle test is prone to many pitfalls; even a slight change in the instructions can bring about a radical change in performance.     

丝状真菌在纤维素酶合成过程中碳源代谢调控的研究进展

丝状真菌可以分泌大量纤维素酶并能有效地降解纤维素底物。在纤维素酶的合成过程中,碳源对产酶微生物有着不可替代的作用,然而对于微生物碳源响应及代谢调控有关的机理仍不是很清楚,从而制约了纤维素酶产业的发展。因此,本文综述了丝状真菌中转录调控因子对纤维素酶合成过程的影响,探讨了真菌在纤维素酶表达过程中对碳源代谢的调控,包括对碳源的响应、碳源对产酶过程的诱导阻遏,并展望了纤维素酶的研究方向。     

Design and application of a screening and training protocol for odour testers in the field of personal care products

The assessment of odours and in particular of human axillary odour is an integral part of the research and development of deodorant and anti-perspirant products. One method to perform odour assessment is the odour evaluation that is carried out by experts, designated as odour testers or sniffers. Product development decisions are therefore based on human assessment. As for every scientific measurement, the influencing factors need to be standardized or regularly calibrated as effectively as possible for reasons of quality assurance. We therefore developed a screening and training concept aiming to examine the general suitability of odour testers by determining the individual odour sensitivity for relevant odours. This newly developed method is based on the national and international standards and guidelines EN 13725:2003, VDI 3882 sheet 1 and ASTM-1207. Suitable odour testers are subsequently trained to correlate their individual odour intensity perception with an intensity calibration scale in order to achieve reproducible results. Training sessions held on a regular basis help to achieve a greater homology in the response of an existing panel. Our established screening and training protocol has already been successfully put into practice and is also subject to permanent improvement with regard to practical requirements.     

Heterologous protein production using the Pichia pastoris expression system

The Pichia pastoris expression system is being used successfully for the production of various recombinant heterologous proteins. Recent developments with respect to the Pichia expression system have had an impact on not only the expression levels that can be achieved, but also the bioactivity of various heterologous proteins. We review here some of these recent developments, as well as strategies for reducing proteolytic degradation of the expressed recombinant protein at cultivation, cellular and protein levels. The problems associated with post-translational modifications performed on recombinant proteins by P. pastoris are discussed, including the effects on bioactivity and function of these proteins, and some engineering strategies for minimizing unwanted glycosylations. We pay particular attention to the importance of optimizing the physicochemical environment for efficient and maximal recombinant protein production in bioreactors and the role of process control in optimizing protein production is reviewed. Finally, future aspects of the use of the P. pastoris expression system are discussed with regard to the production of complex membrane proteins, such as G protein-coupled receptors, and the industrial and clinical importance of these proteins.     

The evolution of a model: A review of Thurstonian and conditional stimulus effects on difference testing

The application of Thurstonian modeling to difference tests is reviewed and explained non-mathematically. How experimental variables can affect the variance of perceptual distributions and reduce discriminability (d′ values) is described. The tendency of triangle and 3-AFC tests with one stronger stimulus and two weaker stimuli to be more sensitive than triads with one weaker and two stronger stimuli, is explained using the idea of conditional stimuli. From this, the development of sequential sensitivity analysis and the four distribution Thurstonian model is described. These ideas are then developed further to produce a potential eight distribution conditional stimulus model, to account for the effects of various interstimulus rinses and cognitive contrast. Also, the physical and physiological properties of the salt taste detection system, used in the development of these models, are outlined.     

Visual attention to rate-all-that-apply (RATA) questions: A case study with apple images as food stimuli

The check-all-that-apply (CATA) question format and variants hereof have become very popular in sensory and consumer research. In the present study, focus is directed to rate-all-that-apply (RATA) questions where participants in addition to selecting terms that are applicable for describing a focal stimulus must also indicate if this term has an intensity corresponding to ‘low’, ‘medium’ or ‘high’. Knowledge of how assessors approach the RATA task is lacking, and this study was dedicated to understanding consumers’ visual attention to RATA questions. This aim was achieved by tracking participants’ eye movements when using a 15-term question to evaluate images of apples with different degrees of internal defect (flesh browning). As expected, participants first looked at the terms, then checked the box corresponding to “applies” and finally selected intensity level, i.e. participants tended to rate attribute intensity immediately after indicating that a term was applicable to describing a focal sample. Commensurate with the two parts to the task, preliminary evidence of more visual attention was suggestive of larger cognitive effort in RATA than CATA questions. Potentially this could be associated with a more “analytical” frame of mind among participants. More visual attention to the RATA question was associated with higher ability to discriminate among samples, in agreement with previous results for CATA questions. Overall, the research supported consumers’ ability to use RATA questions as intended, and indirectly to continued methodological uptake.     

Effects of nicotine and smoking on event-related potentials: a review.

Event-related potentials can serve as an adjunct to reaction time in elucidating the effects of nicotine on rapid human information processing. We review the literature related to nicotine and event-related potentials. Although evidence indicates that, in the visual modality, nicotine enhances early perceptual processing and in certain instances speeding stimulus evaluation, the bulk of nicotine's effects seem to be on enhancing response preparation and response execution.     

An evaluation of the humaneness of puntilla in cattle

Slaughter by puntilla followed by neck sticking was examined in 309 cattle, to assess the humaneness of this method. After the neck stab, brain and spinal function as well as presence of selected cognitive responses were measured. In addition breed, sex, live weight, body condition score, number of stabs given and level of experience of the slaughterman were recorded. Repeat stabbing was needed to penetrate the foramen ovale in 24% of the animals, and was significantly less frequent in slaughtermen who were experienced, and more frequent in heavy weight animals (>380 kg). Prevalence of brain and spinal function was 91%. When animals attempted to stand after the neck stab they were more likely to have rhythmic breathing, positive palpebral response and responsiveness to threat, noise and short air stimulus. These findings indicate that nerve pathways are often functional after neck stab and therefore it is highly likely that the animals are still conscious.     

Destructuring and restructuring of foods during gastric digestion

All foods harbor unique length scale‐dependent structural features that can influence the release, transport, and utilization of macro‐ or micronutrients in the human gastrointestinal tract. In this regard, food destructuring and restructuring processes during gastric passage significantly influence downstream nutrient assimilation and feelings of satiety. This review begins with a synopsis of the effects of oral processing on food structure. Then, stomach‐centric factors that contribute to the efficacy of gastric digestion are discussed, and exemplified by comparing the intragastric de‐ and restructuring of a number of common foods. The mechanisms of how intragastric structuring influences gastric emptying and its relationship to human satiety are then discussed. Finally, recently developed, non‐destructive instrumental approaches used to quantitively and qualitatively characterize food behavior during gastric destructuring and restructuring are described.     

Modeling the sweetness response using time–intensity data

A general mathematical model for the temporal intensity response to a transient sweet stimulus was developed. The model is a set of nonlinear ordinary differential equations, expressing the rates of diffusion across a saliva boundary layer and adsorption and desorption to receptor site proteins on the taste bud cells. In this model, the perceived intensity is considered to be the product of a scaling factor and the amount of stimulus bound to receptor sites at any given time. A parameter estimation routine was used to fit the differential equations to the time–intensity (TI) curves for five equisweet stimuli (sucrose, aspartame, thaumatin, monellin, and brazzein). Model parameters were computed for each of 19 trained judges. The predicted TI curves were close to the observed time-intensity responses for all judges and sweeteners. TI parameters varied significantly across both judges and compounds, while model predicted parameters, such as adsorption and desorption coefficients, varied significantly only across compounds. Except for one model parameter (predicted plateau time), there were no significant differences across judges for the model-predicted parameters, indicating that all judges responded similarly to each compound.     

食源性细菌关键小分子信号通路研究进展

食源性细菌引起的食品腐败和生物被膜形成是食品科学领域关注的热点。研究表明这些现象与细菌群体感应（quorum sensing,QS）系统和第二信使环二鸟苷酸（cyclic di-guanosine monophosphate,c-di-GMP）系统密切相关,深入研究发现细菌可通过利用胞外自诱导物和胞内c-di-GMP分别感知细胞密度和外界刺激来调控一系列生理活性。鉴于此,本文主要围绕食品腐败和生物被膜形成关联的QS和c-di-GMP这两个系统,阐述食源性细菌关键小分子信号通路,探讨QS和c-di-GMP信号通路之间的调控网络,旨在更好地理解食品体系中细菌引起的腐败和生物被膜形成现象,提供保障食品品质与安全的控制靶点。     

Adaptive response of the skin to UVB damage: role of the p53 protein

Different adaptation mechanisms like heat shock response, cell cycle arrest and DNA repair, melanin pigmentation and thickening of the epidermis are present in the human skin to protect against the adverse effects of solar UV irradiation. When DNA damage is beyond repair, cells undergo apoptosis to prevent their replication. We discuss the current knowledge on these different adaptation mechanisms to UVB damage, the most energetic fraction of solar UV that reaches the skin. As p53 protein, the guardian of the genome, plays a key role in protective response to genotoxic damage, its role in this adaptive response of the skin to UV will be further discussed.     

Construction of optimum index to maximize overall response across countries in the presence of genotype x environment interaction

Sire effect is partitioned into two parts: constant effect unaffected by environments and interaction effect specific to each environment and responsible for genotype x environment (GE) interaction. Response to selection for constant effect is the same across environments, thus increasing genetic stability, whereas response to selection for interaction effect would vary depending upon environments. The conventional measure of GE interaction based on genetic correlation (gammaG) considers both constant and interaction components even though the constant component plays no role in GE interaction. In contrast, the proposed measure of GE interaction based on interaction correlation (gammaI) deals only with interaction component responsible for GE interaction and thus indicates the intensity of GE interaction generated by responsible genes. Constant and interaction effects with different economic weights were combined into optimum index to improve both genetic stability and overall response across countries (countries represent environments). Optimum index was more efficient than the unpartitioned index which was more efficient than selection in a single country except when economic weights between constant and interaction effects were equal. Optimum index and unpartitioned index were the same when these economic weights were equal. The advantage of optimum index over the other selection methods increases as the intensity of GE interaction increases. When the relative economic weights are equivalent among countries and between constant and interaction effects, selection in a country with a larger sire variance is more effective than selection in a country with a smaller sire variance.