Structure of soya glycinin and conglycinin gels

Gels of glycinin and conglycinin formed at various heating temperatures, in the absence and presence of 0.2M sodium chloride were characterised by transmission electron microscopy. In distilled water both proteins formed gels consisting of strands with a thickness of 10–15 nm. The strands of glycinin were very regular and cross sections of strands showed a hollow cylindrical structure. In the presence of sodium chloride, glycinin formed an aggregated gel structure at 85°C, but at 95°C an ordered strand structure was formed. Dissociation of the quaternary structure on heating and reassociation of subunits into regular strands were considered the most probable mechanisms for strand formation from glycinin. The aggregated structure at 85°C was interpreted as a transient state prior to dissociation. Conglycinin rich gels were less regular and more crosslinked than gels of glycinin. Also, the strands of conglycinin showed a complex mode of aggregation possibly in the form of double spirals. The addition of sodium chloride caused a denser and more aggregated structure at 75 and 85°C, but the effects were not as drastic as in the case of glycinin. Heating temperature had only minor effects on the gel structure in the range studied.     

Response of shielding structures to explosive loading

This paper presents the results of a numerical and experimental study of the behaviour of a brass hopper held in a supporting structure subjected to internal explosive loading. The structure is typical of those employed during the manufacture of explosive accessories. In such processes the hopper acts as a feed for the explosive while the encasing structure both supports the hopper and provides protection to the surroundings in the event of accidental initiation. The finite element model includes representations of the explosive, the brass hopper and the steel supporting structure. The boundaries between the components are treated as sliding and separable interfaces. Analysis is performed using the Oasys DYNA3D (version 5.1) finite element program. The numerical predictions for the deformations are compared with test results. The DYNA3D finite element code is shown to be an effective tool for the appriasal of this type of protective structure under explosive loading. Both the numerical and experimental studies point the way to improvements in the current design.     

Sodium Coordination Environments in Silica Films

The local structure centered on sodium after diffusion in silica (Na-SiO₂ samples) has been determined by means of extended X-ray absorption fine structure (EXAFS) studies. The Na-SiO₂ samples are of particular interest because (i) their sodium content can be varied over a wide range of concentration and (ii) their local structure is representative of that of soda–silica glass. EXAFS analyses reveal the existence of a well-defined local structure involving oxygen, sodium, and silicon neighbors. The Na-O, Na-Na, and Na-Si bonds lengths, which amount to 0.23, 0.30, and 0.38 nm, respectively, do not depend on sodium concentration. This environment closely resembles that found in soda–silica glass. Moreover, it is compatible with the "target site" and "the site memory effect" suggested by recent theories of the ionic conductivity in oxide glasses.     

Single point incremental forming: state-of-the-art and prospects

Incremental sheet metal forming in general and Single Point Incremental Forming (SPIF) specifically have gone through a period of intensive development with growing attention from research institutes worldwide. The result of these efforts is significant progress in the understanding of the underlying forming mechanisms and opportunities as well as limitations associated with this category of flexible forming processes. Furthermore, creative process design efforts have enhanced the process capabilities and process planning methods. Also, simulation capabilities have evolved substantially. This review paper aims to provide an overview of the body of knowledge with respect to Single Point Incremental Forming. Without claiming to be exhaustive, each section aims for an up-to-date state-of-the-art review with corresponding conclusions on scientific progress and outlook on expected further developments.     

The effect of phone design on upper extremity discomfort and muscle fatigue

OBJECTIVE: To compare a small cellular clamshell phone with a traditional office phone in the development of discomfort and muscle fatigue over time during phone use. BACKGROUND: Phone use involves low-level static exertions that may be influenced by phone design. Phone design and its interactions with anthropometry may change shoulder and hand postures assumed during use, which in turn may modify the length-strength relationship and moment arms of the muscles. METHOD: Ten adults participated in a study that simulated phone use using a small clamshell and a traditional office phone. Discomfort information and electromyographic (EMG) muscle activity were monitored on four upper extremity muscles. Discomfort and fatigue data (EMG median frequency shifts) were analyzed to assess differences between phones as well as differing effects attributable to anthropometry. RESULTS: Median frequency shifts supported discomfort claims and indicated muscle fatigue in the deltoid and thenar muscles. Biomechanical measures demonstrated that participants with short limb lengths developed more severe signs of thenar fatigue. Participants with longer arms developed greater discomfort in the neck, shoulder, and back. The deltoid confirmed this occurrence, showing signs of muscle fatigue. CONCLUSION: Phone design and anthropometry influenced the development of discomfort and fatigue during phone use. Phone design dictated grip style, resulting in differing discomfort and fatigue levels. Anthropometry influenced the severity of the discomfort and fatigue present in the shoulder and hand. APPLICATION: Use of small clamshell phones may contribute to a lack of rest and recovery from typical workday exposures. It should be explored from an ergonomic perspective.     

The influence of lift frequency, lift duration and work experience on discomfort reporting

Discomfort surveys are commonly used to assess risk in the workplace and prioritize jobs for interventions before an injury or illness occurs. However, discomfort is a subjective measure and the relationship of discomfort to work-related factors is poorly understood. The objective of this study was to understand how reports of discomfort relate to work-related risk factors for the low back. A total of 12 novice and 12 experienced manual materials handlers performed repetitive, asymmetric lifts at different load levels and at six different lift frequencies throughout an 8-h exposure period. Discomfort was recorded hourly throughout the day. Analyses were performed to determine which experimental factors influenced reporting of discomfort and if discomfort trends matched spine loading trends. Novice lifters reported significantly higher discomfort levels than experienced subjects. They also reported increases in discomfort as moment exposure increased and as the exposure time increased. Novices lifting at 8 Nm load moment level reported increased discomfort from 0.07 to 0.63 by the end of the day, at 36 Nm they reported an increase from 0.04 to 0.40 and at 85 Nm they reported an increase from 0.37 to 3.06. Experienced subjects, on the other hand, reported low levels of discomfort regardless of moment exposure, lift frequency or exposure duration. The reported discomforts were generally unrelated to the biomechanical loading on the spine. Discomfort reporting appears to be more a reflection of experience than of work risk factor exposure. Experienced subjects may have more efficient motor patterns, which reduce spinal load and thus discomfort. Novice subjects seemed to have a lower threshold of discomfort. Caution is needed when using discomfort reporting as a means to identify jobs in need of interventions, in that biomechanical loading may not be accurately represented. Discomfort should only be used as a supplement to objective measures, such as spinal loading, to assess the risk of low back disorders.     

Isothermal and Dynamic Microcalorimetry for Quantifying the Crystallization of an Amorphous Drug during Interactive Powder Mixing

This study reports the crystallization of amorphous nifedipine during an interactive mixing process quantified by using isothermal and dynamic microcalorimetry. Interactive mixtures of amorphous nifedipine and uniform glass beads were prepared by mixing in a Turbula® mixer. The difference in the extent of crystallization of amorphous nifedipine during mixing was characterized by the time it took for the crystallization of a known amount of amorphous nifedipine in isothermal calorimetry and the change in the height of the crystallization peak at 65°C in dynamic calorimetry. It was found that both isothermal and dynamic microcalorimetry are useful techniques for quantifying the physical transition of amorphous nifedipine during interactive mixing. The rate and extent of crystallization of amorphous nifedipine depended on both mixing time and speed, but mixing time played a more dominant role because the transformation of amorphous to crystalline nifedipine was greater after 3180 revolutions (9.7%) than after 405 revolutions (0.9%) at 27 rpm. The same trend was observed at 109 rpm, but the percentage of crystalline nifedipine after 3180 revolutions was only 5.2%. This meant that an increase in mixing time rather than speed increased the rate of amorphous to crystalline transformation. The greatest cause for crystal transformation during interactive mixing was the presence of crystal seeds of the thermodynamically stable nifedipine Modification I because the amount of amorphous to crystalline transformation increased from 2.6% for a completely amorphous mixture to 6.6% for a 92:8 mixture of amorphous and crystalline nifedipine when mixed for 30 minutes at 106 rpm.     

Mood-Induced Increases in Alcohol Expectancy Strength in Internally Motivated Drinkers.

This study investigated whether exposure to musical mood induction procedures (MMIP) differentially increases the strength of specific alcohol expectancies for coping motivated (CM) versus enhancement motivated (EM) drinkers. Participants were 86 undergraduates who had elevated scores on either the CM or EM subscale of the Drinking Motives Questionnaire (M. L. Cooper, 1994). Participants were randomly assigned to either a positive or negative mood condition. The Alcohol Craving Questionnaire (E. G. Singleton, S. T. Tiffany, & J. E. Henningfield, 1994) was administered at baseline and after MMIP to assess phasic changes in alcohol expectancy strength. Consistent with hypotheses, only CM drinkers in the negative mood condition reported increased relief expectancies, and only EM drinkers in the positive mood condition reported increased reward expectancies. Theoretical and clinical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Registration of confocal scanning laser microscopy and quantitative backscattered electron images for the temporospatial quantification of mineralization density in 18-month old thoroughbred racehorse articular calcified cartilage

Combined backscattered electron scanning electron microscopy (BSE SEM) and confocal scanning laser microscopy (CSLM) have been used to put tissue mineralization data into the context of soft tissue histology and fluorescent label information. Mineralization density (Dm) and linear accretion rate (LAR) are quantifiable parameters associated with mineralizing fronts within calcified tissues. Quantitative BSE (qBSE) may be used to determine Dm, while CSLM may be used to detect label fluorescence from which LAR is calculated. Eighteen-month old Thoroughbred horses received single calcein injections 19 and 8 days prior to euthanasia, labeling sites of active mineralization with fluorescent bands. Confocal scanning laser microscopy images of articular calcified cartilage (ACC) from distal third metacarpal condyles were registered to qBSE images of the same sites using an in-house program. ImageJ and Sync Windows enabled the simultaneous collection of LAR and Dm data. The repeatability of the registration and measurement protocols was determined. Dm profiles between calcein labels were explored for an association with time. Dm was 119.7 +/- 24.5 (mean +/- standard deviation) gray levels (where 0 = backscattering from monobrominated and 255 from monoiodinated dimethacrylate standards, respectively), while modal and maximum LAR were 0.45 and 3.45 microm/day, respectively. Coefficients of variation (CV) for Dm were 0.70 and 0.77% with and without repeat registration, respectively; CVs for LAR were 1.90 and 2.26% with and without repeat registration, respectively. No relationship was identified between Dm and time in the 11-day interlabel interval. Registration of CSLM to qBSE images is sufficiently repeatable for quantitative studies of equine ACC.