Rest break interventions in stoop labor tasks

Hand cultivation and harvest of agricultural products constitute strenuous physical tasks. Working with labor-management ergonomics committees in agricultural settings, the UC Agricultural Ergonomics Research Center (AERC) tested an experimental rest and recovery protocol for its impact on symptoms and productivity during two types of work tasks. The experimental condition consisted of adding a 5 min rest break to every working hour in which there was no other scheduled break (e.g., lunchtime). This resulted in an additional 20 min of rest per workday. We tested the intervention in two trials: Trial one compared workers (n=66) randomly assigned to an experimental or a control group during the harvest of commercial strawberries. Trial two utilized a cross-over design (n=16 pairs of workers) to compare experimental and control conditions while workers inserted bud grafts into young 18' high citrus trees. For both trials, workers under the experimental condition reported significantly less severe symptoms than workers under control conditions. The order in which the intervention was given, however, appeared to result in variations in productivity. We conclude that the introduction of frequent, brief rest breaks may improve symptoms for workers engaged in strenuous work tasks.     

A route to highly porous grinding wheels by selective extraction of pore inducers with dense carbon dioxide

A novel route for the production of highly porous vitrified grinding wheels was developed via selective extraction of pore inducers with dense CO₂. The extraction was performed with liquid and supercritical CO₂ (scCO₂) at temperatures ranging from 295 to 338 K, pressures from 8.8 to 27.6 MPa and flow rates of 3.4×10⁻⁵ and 7.5×10⁻⁵ kg s⁻¹ CO₂. The extraction rate was a strong function of temperature, flow rate, and flow direction, while unaffected by particle size of the pore inducer and pressure. The extraction had no detrimental effect on the green wheel’s microstructure. Grinding tests were performed on the CO₂ extracted pore induced wheels and results were compared to those from a conventionally manufactured pore induced grinding wheel. The extracted grinding wheels performed similarly to the conventional wheels. At high metal removal rates, the extracted wheels with large pore sizes outperformed the wheels with smaller particle sizes as well as the conventional wheel. This may be due to the larger pore sizes increasing lubrication at the surface and increasing the wheel strength.     

Iron and vitamin A deficiencies and prevalence of anemia in boys and girls between 6 to 24 months of age in Chaco,Argentina

To determine the prevalence of anemia, and iron (ID) and vitamin A deficiencies aiming at their prevention, 414 children between 6 and 24 months of age, were randomly selected from the whole province of Chaco. A sociodemographic survey was implemented, and hemoglobin (Hb), plasma ferritin and retinol were measured. Anemia prevalence (Hb < 110 g/L) was 66.4%, without differences between age groups, and included 18% with Hb < 90 g/L. These cases were significantly less in children 6-8 month of age (5.1%) than in the others (approximately equal to 20%) (P: 0.007). Mean Hb was also higher in 6-8 months old children and was associated with lower prevalence of ID (ferritin < 12 micrograms/L) (p < 0.000) but not with age (p = 0.8865). ID already present, however, in 36.6% of children in this age group, reached a prevalence of 72.9% in children older than 18 months. Anemia prevalence was significantly higher in males, in children whose birth weight was < 3000 g, in those who had never taken iron supplements and among the poor, both structural and by income. Retinol values < 20 micrograms/dl occurred only in 5.1% of children. Iron nutrition prior to, during pregnancy and in children during the first 2 years of life must be improved by joining strategies based on community empowerment aimed at improving dietary iron, assuring effective preventive supplementation and promoting the opportune umbilical cord ligation.     

Catalytic dehydrochlorination of the solid poly(vinyl chloride) in the presence of aluminium chloride (friedel-crafts) catalyst: Studies of the structure by spectroscopical methods

Catalytic dehydrochlorination (100%) of solid poly(vinyl chloride) (PVC) in the presence of AlCl₃ at 200°C gives a product which has a similar structure to the product of catalytic dehydrochlorination of 1,2-dichloroethane in the presence of AlCl₃ at 60°C. Both products have brown-black color, are completely insoluble, thermally resistant up to more than 400°C, and exhibit conductivities in the range 10^?6 S cm^?1 (after doping with FeCl₃ or I₂ conductivities: 10^?5 S cm^?1). Different spectroscopical methods such as UV/VIS, IR, Raman, ESCA, and ¹³C-NMR were employed to the structure study of both products, which are crosslinked polyenes with a number of aromatic rings.     

Social interaction and reflection for behaviour change

This article introduces the theme issue on social interaction and reflection for behaviour change. A large body of research exists on systems designed to help users in changing their behaviours, for instance, to exercise more regularly or to reduce energy consumption. Increasingly, these systems focus on multiple users, often to encourage open-ended reflection rather than prescribing a particular course of action. As background for this theme issue, this article presents a literature review on behaviour change support systems that focus on social interaction and reflection. The review highlights five key approaches amongst these systems: social traces, social support, collective use, reflection-in-action, and reflection-on-action. Each approach offers unique benefits, but also challenges for the design of behaviour change support systems. We highlight how the articles in this theme issue contribute to our current understanding of these five approaches, and beyond that, set out some broad directions for future work.     

Wet‐Route Synthesis and Characterization of Yb:CaF2 Optical Ceramics

This paper reports a new strainless fabrication method for ytterbium‐doped CaF₂ laser ceramics involving no drying step before green body casting. The nanoparticles were kept in aqueous solution until green body shaping. Centrifugation was used to obtain correct compactness of the green body before sintering. Characterizations were conducted at different steps of the fabrication process. No grain boundaries oxidation was observed in the sintered ceramics although the nanoparticles were permanently maintained in water until they were sintered. Finally, these ceramics are more homogeneous and have less light scattering defects (no porosity), and present improved optical properties when compared to ceramics obtained from dried nanopowders.     

Analysis of wear of fused silica moulding using glassy carbon moulds

Optical components made of fused silica are in great demand due to the material’s exceptional properties: a broad transmission range from 185 nm to 2.5 μm, low coefficient of thermal expansion, low thermal conductivity and high radiation resistance. For the production of complex optical components in medium and large quantities, the technology of precision glass moulding is particularly suitable. Here, a glass blank is heated up to the moulding temperature and moulded into the desired shape by means of two moulding tools without any subsequent work. The production of the complex moulding tools is still costly in terms of labor and time but the efficiency of the process increases with the number of optical components made by using a pair of moulding tools. Hence, the wear of the moulding tools determines the efficiency of the process. In this paper, an experimental study and FE simulation are presented in order to investigate the wear of the glassy carbon moulding tools in moulding of fused silica. For the FE simulation, the viscoelasticity of fused silica and the friction coefficient between fused silica and glassy carbon were determined. The influence of the process parameters temperature and pressing force on the wear of moulding tools was analysed.     

Antibody Epitope of Human α‐Galactosidase A Revealed by Affinity Mass Spectrometry: A Basis for Reversing Immunoreactivity in Enzyme Replacement Therapy of Fabry Disease

α‐Galactosidase (αGal) is a lysosomal enzyme that hydrolyses the terminal α‐galactosyl moiety from glycosphingolipids. Mutations in the encoding genes for αGal lead to defective or misfolded enzyme, which results in substrate accumulation and subsequent organ dysfunction. The metabolic disease caused by a deficiency of human α‐galactosidase A is known as Fabry disease or Fabry–Anderson disease, and it belongs to a larger group known as lysosomal storage diseases. An effective treatment for Fabry disease has been developed by enzyme replacement therapy (ERT), which involves infusions of purified recombinant enzyme in order to increase enzyme levels and decrease the amounts of accumulated substrate. However, immunoreactivity and IgG antibody formation are major, therapy‐limiting, and eventually life‐threatening complications of ERT. The present study focused on the epitope determination of human α‐galactosidase A against its antibody formed. Here we report the identification of the epitope of human αGal(309–332) recognized by a human monoclonal anti‐αGal antibody, using a combination of proteolytic excision of the immobilized immune complex and surface plasmon resonance biosensing mass spectrometry. The epitope peptide, αGal(309–332), was synthesized by solid‐phase peptide synthesis. Determination of its affinity by surface plasmon resonance analysis revealed a high binding affinity for the antibody (K_D=39×10^?9 m ), which is nearly identical to that of the full‐length enzyme (K_D=16×10^?9 m ). The proteolytic excision affinity mass spectrometry method is shown here to be an efficient tool for epitope identification of an immunogenic lysosomal enzyme. Because the full‐length αGal and the antibody epitope showed similar binding affinities, this provides a basis for reversing immunogenicity upon ERT by: 1) treatment of patients with the epitope peptide to neutralize antibodies, or 2) removal of antibodies by apheresis, and thus significantly improving the response to ERT.     

Probing structures of nanomaterials using advanced electron microscopy methods, including aberration-corrected electron microscopy at the Angstrom scale

Structural and compositional studies of nanomaterials of technological importance have been carried out using advanced electron microscopy methods, including aberration-corrected transmission electron microscopy (AC-TEM), AC-high angle annular dark field scanning TEM (AC-HAADF-STEM), AC-energy filtered TEM, electron-stimulated energy dispersive spectroscopy in the AC-(S)TEM and high-resolution TEM (HRTEM) with scanning tunneling microscopy (STM) holder. The AC-EM data reveal improvements in resolution and minimization in image delocalization. A JEOL 2200FS double-AC field emission gun TEM/STEM operating at 200 kV in the Nanocentre at the University of York has been used to image single metal atoms on crystalline supports in catalysts, grain boundaries in nanotwinned metals, and nanostructures of tetrapods. Joule heating studies using HRTEM integrated with an STM holder reveal in situ crystallization and edge reconstruction in graphene. Real-time in situ AC-HAADF-STEM studies at elevated temperatures are described. Dynamic in-column energy filtering in an AC environment provides an integral new approach to perform dynamic in situ studies with aberration correction. The new results presented here open up striking new opportunities for atomic scale studies of nanomaterials and indicate future development directions.     

Interstellar dust laser explorer: a new instrument for elemental and isotopic analysis and imaging of interstellar and interplanetary dust

We present the performance characteristics of a time-of-flight secondary ion mass spectrometer designed for 157 nm laser postionization of sputtered neutrals for high sensitivity elemental and isotopic analyses. The instrument was built with the aim of analyzing rare element abundances in micron to submicron samples such as interstellar grains and cometary dust. Relative sensitivity factors have been determined for secondary ion mass spectrometry which show an exponential dependency against the first ionization potential. This allows elemental abundances to be measured with errors below 25% for most major elements. The accuracy for isotope ratios, where isotopes can be resolved from isobaric interferences, is usually limited only by counting statistics. In laser secondary neutral mass spectrometry, the spatial and temporal overlaps between the laser and sputtered neutral atoms are modeled and predictions of total detection efficiency and isotopic and elemental fractionation are compared with experimental data. Relative sensitivity factors for laser-ionized secondary neutrals from a stainless steel standard are found to vary less than 3% above saturation laser pulse energy enabling more accurate quantification.