The field of 3D printing is continuing its rapid development in both academic and industrial research environments. The development of 3D printing technologies has opened new implementations in rapid prototyping, tooling, dentistry, microfluidics, biomedical devices, tissue engineering, drug delivery, etc. Among different 3D printing techniques, photopolymerization-based process (such as stereolithography and digital light processing) offers flexibility over the final properties of the 3D printed materials (such as optical, chemical, and mechanical properties) using versatile polymer chemistry. The strategy behind the 3D photopolymerization is based on using monomers/oligomers in liquid state (in the presence of photoinitiators) that can be photopolymerized (via radical or cationic mechanism) upon exposure to light source of different wavelengths (depending on the photoinitiator system). An overview of recent evolutions in the field of photopolymerization-based 3D printing and highlights of novel 3D print...

Photopolymerization in 3D Printing

The Textbook of Contact Dermatitis covers every conceivable aspect of modern day management of contact dermatitis. Both irritatnt and allergic types of contact dermatitis are dealt with clearly and comprehensively, special emphasis being given to occupational aspects as well as to prevention, diagnosis and treatment. Also covered are epidemiological aspects, computerization of patch test data and patient imformation systems, noninvasive bioengineering measurement techniques, methods of skin testing other than patch testing, histopathology of both irritant and allergic contact dermatitis, and subjective reactions. The editors and contributing authors are all leading practitioners in the field. Their expertise has been brought to bear to

Textbook of Contact Dermatitis

Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft...

Molecular mechanisms of aldehyde toxicity: a chemical perspective.

Methanol could become a major automotive fuel in the U.S., and its use may result in increased exposure of the public to methanol vapor. Nearly all of the available information on methanol toxicity in humans relates to the consequences of acute, rather than chronic, exposures. Acute methanol toxicity evolves in a well-understood pattern and consists of an uncompensated metabolic acidosis with superimposed toxicity to the visual system. The toxic properties of methanol are rooted in the factors that govern both the conversion of methanol to formic acid and the subsequent metabolism of formate to carbon dioxide in the folate pathway. In short, the toxic syndrome sets in if formate generation continues at a rate that exceeds its rate of metabolism. Current evidence indicates that formate accumulation will not challenge the metabolic capacity of the folate pathway at the anticipated levels of exposure to automotive methanol vapor.

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The Toxicity of Inhaled Methanol Vapors

Background: Acrylamide (ACR) produces cumulative neurotoxicity in exposed humans and laboratory animals through a direct inhibitory effect on presynaptic functionObjectives: In this review, we del

Molecular mechanism of acrylamide neurotoxicity: lessons learned from organic chemistry.

Multifunctional acrylates and methacrylates (MFA) represent a class of materials with considerable chemical reactivity that are used in many applications with opportunity for contact exposure They represent appreciable eye and skin contact hazards, and several members of the class may be absorbed from skin to cause systemic effects A number of MFAs have been identified as sensitizers While the acute toxicity of MFAs is certain, the effects of repeated or chronic exposure are less clear Data are presented that suggest that MFAs are not appreciable fetotoxic or teratogenic hazards and do not elicit a strong carcinogenic response following chronic dermal exposure The use of these data for product safety purposes and research needs is discussed

Review of the toxicity of multifunctional acrylates

The subchronic inhalation toxicity of methanol was evaluated in rats and monkeys. Animals were exposed to 0, 500, 2000, and 5000 ppm methanol vapor for 6 h/d, 5 d/w, for 4 wk. The only treatment‐ and dose‐related effect noted was that of mucoid nasal discharge in rats, which was considered reflective of upper respiratory tract irritation. No consistent treatment‐related effects were found for organ or body weights or for histopathologic or ophthalmoscopic examinations. Overall, these findings support the use of the present American Council of Governmental Industrial Hygienists threshold limit value (TLV) of 200 ppm and short‐term exposure limit (STEL) of 250 ppm for exposure to methanol vapor.

L. S. Andrews

Papers

Review of the toxicity of multifunctional acrylates

Subchronic inhalation toxicity of methanol