The Effect of Cellulose Nanocrystal Reassembly on Latex-Based Pressure-Sensitive Adhesive Performance.

Different cellulose nanocrystal (CNC) forms (dried vs never-dried) can lead to different degrees of CNC reassembly, the formation of nanofibril-like structures, in nanocomposite latex-based pressure-sensitive adhesive (PSA) formulations. CNC reassembly is also affected by CNC sonication and loading as well as the protocol used for CNC addition to the polymerization. In this study, carboxylated CNCs (cCNCs) were incorporated into a seeded, semibatch, 2-ethylhexyl acrylate/methyl methacrylate/styrene emulsion polymerization and cast as pressure-sensitive adhesive (PSA) films. The addition of CNCs led to a simultaneous increase in tack strength, peel strength, and shear adhesion, avoiding the typical trade-off between the adhesive and cohesive strength. Increased CNC reassembly resulted from the use of dried, redispersed, and sonicated cCNCs, along with increased cCNC loading and addition of the cCNCs at the seed stage of the polymerization. The increased degree of CNC reassembly was shown to significantly increase the shear adhesion by enhancing the elastic modulus of the PSA films.

Electrokinetic Manipulation of Biological Cells towards Biotechnology Applications.

The presented study demonstrates the capability of the template-based electrokinetic assembly (TEA) and guidance to manipulate and capture individual biological cells within a microfluidic platform. Specifically, dielectrophoretic (DEP) focusing of K-562 cells towards lithographically-defined "wells" on the microelectrodes and positioning singles cells withing these "wells" was demonstrated. K-562 lymphoblast cells, are widely used in immunology research. The DEP guidance, particularly involving positive DEP (pDEP), enables the controlled guidance and positioning of conductive and dielectric particles, including biological cells, opening new directions for the accurate and efficient microassembly of biological entities, which is crucial for single cell analysis and other applications in biotechnology. The investigation explores the use of glassy carbon and gold as electrode materials. It was established previously that undiluted physiological buffer is unsuitable for inducing positive DEP (pDEP); therefore, the change of media into a lower ionic concentration is necessary. After pDEP was observed, the cells are resubmerged in the Iscove's modified Dulbecco's medium (IMEM), a cell culturing media, and incubated. A dead/alive staining assay was performed on the cells to determine their survival in the diluted buffer for the period required to capture them. The staining assay confirmed the cells' survival after being immersed in the diluted biological buffer necessary for electrokinetic handling. The results indicate the promise of the proposed electrokinetic bio-sorting technology for applications in tissue engineering, lab-on-a-chip devices, and organ-on-a-chip models, as well as contributing to the advancement of single cell analysis.

Colloidal Stability Window for Carboxylated Cellulose Nanocrystals: Considerations for Handling, Characterization, and Formulation.

The scale of production of cellulose nanocrystals (CNCs) has increased dramatically to meet the growing demand for sustainably sourced materials. This work defines the colloidal stability window for commercially produced carboxylated CNCs (DextraCel) compared to the more traditional sulfated CNCs. Phase diagrams showing the stable, reversibly agglomerated, irreversibly aggregated/sedimented, and colloidal glass "zones" as a function of suspension pH, ionic strength, CNC surface charge content, counterion, and concentration are presented. The pKa of carboxylated CNCs was measured to be 5.1, and suspensions of carboxylated CNCs (0.5-1.5 wt %) were visually stable from pH 3 to 11 (without salt). Carboxylated CNCs were highly sensitive to ionic strength, demonstrating some agglomeration with as little as 5 mM NaCl, supporting that weak acid surface groups and lower charge contents make CNCs more sensitive to solution conditions. Surface charge content had the greatest influence on colloidal stability followed by the counterion; carboxylated CNCs were more stable in the "as-received" sodium form, whereas sulfated CNCs had improved stability in acid form after ion exchange. The stability of carboxylated CNCs with industrially relevant additives (ionic and nonionic surfactants and initiators) was also investigated. Less concentrated suspensions were more colloidally stable, emphasizing that characterization and processing of CNCs favor dilute conditions. If carboxylated CNCs are subjected to conditions outside of their colloidal stability window, simple dilution or pH adjustment does not return them to colloidally stable discrete nanoparticles; however, ultrasonication can redisperse agglomerates. This study offers guidelines for handling carboxylated CNCs to broaden the range of products that can be improved by their incorporation.

The design of a low literacy decision aid about rheumatoid arthritis medications developed in three languages for use during the clinical encounter.

BACKGROUND: Shared decision-making in rheumatoid arthritis (RA) care is a priority among policy makers, clinicians and patients both nationally and internationally. Demands on patients to have basic knowledge of RA, treatment options, and details of risk and benefit when making medication decisions with clinicians can be overwhelming, especially for those with limited literacy or limited English language proficiency. The objective of this study is to describe the development of a medication choice decision aid for patients with rheumatoid arthritis (RA) in three languages using low literacy principles. METHODS: Based on the development of a diabetes decision aid, the RA decision aid (RA Choice) was developed through a collaborative process involving patients, clinicians, designers, decision-aid and health literacy experts. A combination of evidence synthesis and direct observation of clinician-patient interactions generated content and guided an iterative process of prototype development. RESULTS: Three iterations of RA Choice were developed and field-tested before completion. The final tool organized data using icons and plain language for 12 RA medications across 5 issues: frequency of administration, time to onset, cost, side effects, and special considerations. The tool successfully created a conversation between clinician and patient, and garnered high acceptability from clinicians. CONCLUSIONS: The process of collaboratively developing an RA decision aid designed to promote shared decision making resulted in a graphically-enhanced, low literacy tool. The use of RA Choice in the clinical encounter has the potential to enhance communication for RA patients, including those with limited health literacy and limited English language proficiency.

Anterior iliac crest, posterior iliac crest, and proximal tibia donor sites: a comparison of cancellous bone volumes in fresh cadavers.

PURPOSE: The anterior iliac crest, posterior iliac crest, and proximal tibia are common cancellous donor sites used for autogenous bone grafting. Donor site selection is partly dependent on the expected volume of available bone, but reports of cancellous bone volumes at each of these sites are variable. The goal of this study was to compare the volumes of cancellous bone harvested from donor sites within the same cadaver. MATERIALS AND METHODS: Within each of 10 fresh frozen cadavers, cancellous bone was harvested from 3 donor sites-anterior iliac crest, posterior iliac crest, and proximal tibia-using established surgical techniques. Bone volumes were measured by fluid displacement. Mean compressed cancellous bone volumes from the 3 donor sites were compared among cadavers. Within each cadaver, the 3 donor sites were given a volume rank score from 1 (least volume) to 3 (most volume). RESULTS: Among cadavers, mean compressed cancellous bone volumes from the proximal tibia (11.3 mL) and posterior iliac crest (10.1 mL) were significantly greater than the anterior iliac crest (7.0 mL). Within cadavers, the mean volume rank score of the proximal tibia (mean rank, 2.7) was statistically greater than that for the posterior iliac crest (mean rank, 2.0), which was statistically greater than that for the anterior iliac crest (mean rank, 1.2). Strong correlations in bone volume existed between the proximal tibia and iliac crests (r = 0.67) and between the anterior iliac crest and posterior iliac crest (r = 0.93). CONCLUSION: The proximal tibia and posterior iliac crest yielded a significantly greater mean volume of compressed cancellous bone than the anterior iliac crest. Within individual cadaver skeletons, the proximal tibia was most likely to yield the largest cancellous volume, whereas the anterior iliac crest was most likely to yield the smallest cancellous volume. Although the proximal tibia contains relatively large volumes of cancellous bone, further investigation is required to determine how much cancellous bone can safely be harvested.

Training health and safety committees to use control banding: lessons learned and opportunities for the United States.

Control banding (CB) is a control-focused risk management model that has received international attention. CB strategies are designed to control workplace chemical exposures after the completion of a qualitative risk assessment. Connecticut was one of the first states to provide training on how to use this control-focused tool. Joint labor/management teams and individuals from 34 workplaces attended a control banding workshop and learned how to use one CB model, the United Kingdom (UK) Health and Safety Executive's Control of Substances Hazardous to Health (COSHH) Essentials Toolkit. After the initial training program the investigators used follow-up workshops, questionnaires, site visit data, and case studies to evaluate the training curriculum and assess the utility and effectiveness of this CB strategy. We found that the model is easily learned, although several areas for improvement were identified. Participants from 10 workplaces used COSHH Essentials to evaluate at least one task. The training curriculum was effective in that the agreement between the exposure variables coded by these workplaces and one of the workshop instructors, a certified industrial hygienist (CIH), were highly concordant. The training curriculum and the model promoted a discussion of risk between workers and managers and resulted in the implementation of improvements in the work environment. The model agreed with both the CIH's and the worksites' qualitative risk assessments 65% of the time, and likely over-controlled for 71% (5/7) of the cases of nonagreement. Feedback from workshop participants benefits the current dialogue on the implications of implementing CB in the United States.

Vibration exposure and disease in a shipyard: a 13-year revisit.

BACKGROUND: In a 1988 study of shipyard workers, a progressive association was observed between cumulative exposure to vibration and the vascular and neurological symptoms of the hand-arm vibration syndrome (HAVS). In 2001, after a decade of exposure reduction and ageing of the workforce, a second study at the same site was initiated. METHODS: In 2001, 214 subjects were selected; they represented four current weekly vibration exposure time intervals--0 hr, >0 < 5 hr, > or =5 < 20 hr, > or =20 hr. The 1988 and 2000 cross-sectional populations were compared on the basis of exposure duration and current symptoms. RESULTS: In 2001, the study population was 9.6 years older than the 1988 group. Current weekly exposure hours were similar in the low and medium exposure groups 2001 and 1988, but exposure was reduced by an average of 9.7 hr per week in the highest exposure group (> or =20 hr) in 2001. Symptom severity was regressed polychotomously on estimated exposure (log cumulative hours); the OR was weaker in 2001 than in 1988 for sensorineural symptoms-1.44 [CI 1.04-1.98] versus 2.35 [CI 1.48-3.73]. This was also true for vascular symptoms-1.70 [CI 1.06-2.71] versus 3.99 [CI 2.27-7.01]. Vascular symptoms were more prevalent in the highest lifetime vibration exposure group in 1988 (68.7 vs. 43.2% in 2001); sensorineural symptoms were more prevalent in the least vibration exposed group in 2001 (52.6 vs. 20.7% in 1988). CONCLUSIONS: The prevalence of vascular symptoms associated with cumulative vibratory exposure was significantly greater in 1988, but neurological symptoms were more common at lower exposure levels in 2001. The presumption that reducing exposure duration alone is sufficient, in the absence of change in vibration magnitude, is not supported by the results of this study.