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Toxicology and Industrial Health Jun 2023A sampling chamber was developed for emission testing of diisocyanates, methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and corresponding diamines,...
A sampling chamber was developed for emission testing of diisocyanates, methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and corresponding diamines, methylene diphenyl diamine (MDA), and toluene diamine (TDA) from polyurethane (PU) product surfaces. In addition, a methodology for validation of the sampling chamber was presented, based on the introduction of generated standard atmospheres of the different diisocyanates and diamines to the sampling chamber system. Sampling of diisocyanates and diamines was performed on a circular glass fiber filter (150 mm diameter) impregnated with dihexyl amine (DHA) and acetic acid (AA) positioned inside a cylindrical stainless steel sampling chamber. The diisocyanates were immediately derivatized to DHA derivatives, and the amines were derivatized in a subsequent work-up procedure with ethyl chloroformate (ECF). The design of the sampling chamber and the presented methodology allowed for simultaneous sampling and analysis of diisocyanates and diamines of emission from a large surface area with minimal interior wall interaction in the sampling chamber. Performance characteristics of the sampling chamber for different sampling times and air humidity were obtained by determining collected amounts of the diisocyanates and diamines in the different parts of the sampling chamber. The repeatability of the collected amount on the impregnated filters in the sampling chamber was 15% with an overall recovery for 8 h of sampling in the range of 61% to 96%. The performance of the sampling chamber was not affected by air humidity (5%-75% RH), and no breakthrough during sampling was observed. LC-MS/MS determinations allowed for emission testing of diisocyanates and diamines on product surfaces as low as 10-30 ng m h.
Topics: Polyurethanes; Diamines; Chromatography, Liquid; Tandem Mass Spectrometry; Isocyanates; Toluene 2,4-Diisocyanate; Amines
PubMed: 37134012
DOI: 10.1177/07482337231172811 -
Caries Research 2014Determination of the potential of cerium chloride to reduce artificial carious mineral loss and lesion depth progression. (Comparative Study)
Comparative Study
AIM
Determination of the potential of cerium chloride to reduce artificial carious mineral loss and lesion depth progression.
METHODS
A total of 160 enamel samples were prepared from 40 bovine lower central incisors. Crowns were sectioned into four pieces, embedded in acrylic resin, ground flat and allocated to eight groups (S1-S4 and D1-D4; n = 20). Specimens of groups D1-D4 were stored (for 7 days) in a demineralizing buffer solution to induce caries-like lesions. Afterwards, samples were treated for 30 s with one of the following solutions: placebo (S1 and D1), amine fluoride (S2 and D2), cerium chloride (S3 and D3) and a combination of fluoride and cerium chloride (S4 and D4). After another 7 (D1-D4) or 14 (S1-S4) days in demineralizing buffer solution, integrated mineral loss and lesion depth were determined by transversal microradiography and compared by Scheffé's post hoc tests.
RESULTS
In groups S1-S4, the highest values for integrated mineral loss and lesion depth were observed for group S1 (placebo), the lowest values for group S4. The results in groups S2-S4 were not significantly different. In groups D1-D4, the highest values for integrated mineral loss and lesion depth were observed for group D1 (placebo), the lowest values in groups D3 and D4. In group D2, integrated mineral loss and lesion depth were significantly lower as compared to D1, but significantly higher compared to groups D3 and D4.
CONCLUSION
Cerium chloride and its combination with fluoride are able to significantly reduce carious mineral loss and the progression of lesion depth.
Topics: Animals; Cariostatic Agents; Cattle; Cerium; Dental Enamel; Diamines; Disease Progression; Drug Combinations; Fluorides; Microradiography; Minerals; Placebos; Time Factors; Tooth Demineralization
PubMed: 24247975
DOI: 10.1159/000351691 -
Contact Dermatitis Oct 2017Isocyanates are used in polyurethane production. Dermal exposure to isocyanates can induce contact allergy. The most common isocyanate is diphenylmethane diisocyanate...
Sensitization and cross-reactivity patterns of contact allergy to diisocyanates and corresponding amines: investigation of diphenylmethane-4,4'-diisocyanate, diphenylmethane-4,4'-diamine, dicyclohexylmethane-4,4'-diisocyanate, and dicylohexylmethane-4,4'-diamine.
BACKGROUND
Isocyanates are used in polyurethane production. Dermal exposure to isocyanates can induce contact allergy. The most common isocyanate is diphenylmethane diisocyanate used for industrial purposes. The isomer diphenylmethane-4,4'-diisocyanate (4,4'-MDI) is used in patch testing. Diphenylmethane-4,4'-diamine (4,4'-MDA) is its corresponding amine. Concurrent reactions to 4,4'-MDI and 4,4'-MDA have been reported, as have concurrent reactions to 4,4'-MDI and dicyclohexylmethane-4,4'-diisocyanate (4,4'-DMDI).
OBJECTIVES
To investigate the sensitization capacities and the cross-reactivity of 4,4'-MDI, 4,4'-MDA, 4,4'-DMDI, and dicyclohexylmethane-4,4'-diamine (4,4'-DMDA).
METHODS
The guinea-pig maximization test (GPMT) was used.
RESULTS
The GPMT showed sensitizing capacities for all investigated substances: 4,4'-MDI, 4,4'-MDA, 4,4'-DMDI, and 4,4'-DMDA (all p < 0.001). 4,4'-MDI-sensitized animals showed cross-reactivity to 4,4'-MDA (p < 0.001) and 4,4'-DMDI (all p < 0.05). 4,4'-MDA-sensitized animals showed cross-reactivity to 4,4'-DMDA (p = 0.008).
CONCLUSION
All of the investigated substances were shown to be strong sensitizers. Animals sensitized to 4,4'-MDI showed cross-reactivity to 4,4'-MDA and 4,4'-DMDI, supporting previous findings in the literature. The aromatic amine 4,4'-MDA showed cross-reactivity to the aliphatic amine 4,4'-DMDA.
Topics: Allergens; Amines; Aniline Compounds; Animals; Benzhydryl Compounds; Cross Reactions; Cyanates; Cyclohexanes; Cyclohexylamines; Dermatitis, Allergic Contact; Diamines; Guinea Pigs; Humans; Isocyanates; Patch Tests; Polyurethanes
PubMed: 28555927
DOI: 10.1111/cod.12809 -
Communications Biology Jul 2022Directly Observed Treatment Short-course (DOTs), is an effective and widely recommended treatment for tuberculosis (TB). The antibiotics used in DOTs, are immunotoxic...
Directly Observed Treatment Short-course (DOTs), is an effective and widely recommended treatment for tuberculosis (TB). The antibiotics used in DOTs, are immunotoxic and impair effector T cells, increasing the risk of re-infections and reactivation. Multiple reports suggest that addition of immune-modulators along with antibiotics improves the effectiveness of TB treatment. Therefore, drugs with both antimicrobial and immunomodulatory properties are desirable. N-(Adamantan-2-yl)-N-[(2E)-3,7-dimethylocta-2,6-dien-1-yl]ethane-1,2-diamine (SQ109) is an asymmetric diamine derivative of adamantane, that targets Mycobacterial membrane protein Large 3 (MmpL3). SQ109 dissipates the transmembrane electrochemical proton-gradient necessary for cell-wall biosynthesis and bacterial activity. Here, we examined the effects of SQ109 on host-immune responses using a murine TB model. Our results suggest the pro-inflammatory nature of SQ109, which instigates M1-macrophage polarization and induces protective pro-inflammatory cytokines through the p38-MAPK pathway. SQ109 also promotes Th1 and Th17-immune responses that inhibit the bacillary burden in a murine model of TB. These findings put forth SQ109 as a potential-adjunct to TB antibiotic therapy.
Topics: Adamantane; Animals; Antitubercular Agents; Ethylenediamines; Macrophages; Mice; Mycobacterium tuberculosis; Tuberculosis; p38 Mitogen-Activated Protein Kinases
PubMed: 35902694
DOI: 10.1038/s42003-022-03693-2 -
Applied and Environmental Microbiology Dec 2014Touching of contaminated objects and surfaces is a well-known method of virus transmission. Once they are attached to the hands, viruses can easily get adsorbed and...
Touching of contaminated objects and surfaces is a well-known method of virus transmission. Once they are attached to the hands, viruses can easily get adsorbed and initiate infection. Hence, disinfection of frequently touched surfaces is of major importance to prevent virus spreading. Here we studied the antiviral activity of a glucoprotamin-containing disinfectant against influenza A virus and the model virus vaccinia virus (VACV) dried on inanimate surfaces. The efficacy of the surface disinfectant on stainless steel, polyvinyl chloride, and glass coupons was investigated in a quantitative carrier test. Vacuum-dried viruses were exposed to 0.25%, 0.5%, and 1% disinfectant for 5 min, 15 min, and 30 min without agitation, and residual infectivity was determined by endpoint titration. Although glucoprotamin was highly active against both viruses in suspension, limited antiviral activity against the surface-dried viruses was detected. Even after 30 min of exposure to 1% disinfectant, VACV was not completely inactivated. Furthermore, influenza A virus inactivation was strongly affected by the surface composition during the 5-min and 15-min treatments with 0.25% and 0.5% disinfectant. The results presented in this study highlight the relevance of practical tests to assess the antiviral activity of surface disinfectants. High virucidal activity in solution is not necessarily indicative of high antiviral activity against surface-dried viruses. In addition, we want to emphasize that the mere exposure of surfaces to disinfectants might not be sufficient for virus inactivation and mechanical action should be applied to bring attached viruses into contact with virucidal compounds.
Topics: Desiccation; Diamines; Disinfectants; Disinfection; Environmental Microbiology; Influenza A virus; Microbial Sensitivity Tests; Microbial Viability; Pyrrolidinones; Time Factors; Vaccinia virus
PubMed: 25217017
DOI: 10.1128/AEM.02462-14 -
Analytical Chemistry Feb 2019An optical molecular imaging contrast agent that is tailored toward lymphatic mapping techniques implementing near-infrared (NIR) fluorescence image-guided navigation in...
An optical molecular imaging contrast agent that is tailored toward lymphatic mapping techniques implementing near-infrared (NIR) fluorescence image-guided navigation in the planning and surgical treatment of cancers would significantly aid in enabling the real-time visualization of the potential metastatic tumor-draining lymph node(s) for their needed surgical biopsy and/or removal, thereby ensuring unmissed disease to prevent recurrence and improve patient survival rates. Here, the development of the first NIR fluorescent rosol dye (THQ-Rosol) tailored to overcome the limitations arising from the suboptimal properties of the generic molecular fluorescent dyes commonly used for such applications is described. In developing THQ-Rosol, we prepared a progressive series of torsionally restrictive N-substituted non-NIR fluorescent rosol dyes based on density functional theory (DFT) calculations, wherein we discerned high correlations amongst their calculated energetics, modeled N-C3' torsion angles, and evaluated properties. We leveraged these strong relationships to rationally design THQ-Rosol, wherein DFT calculations inspired an innovative approach and synthetic strategy to afford an uncharged xanthene core-based scaffold/molecular platform with an aptly elevated p K value alongside NIR fluorescence emission (ca.700-900 nm). THQ-Rosol exhibited 710 nm NIR fluorescence emission, a 160 nm Stokes shift, robust photostability, and an aptly elevated p K value (5.85) for affording pH-insensitivity and optimal contrast upon designed use. We demonstrated the efficacy of THQ-Rosol for lymphatic mapping with in vitro and in vivo studies, wherein it revealed timely tumor drainage and afforded definitive lymph node visualization upon its administration and accumulation. THQ-Rosol serves as a proof-of-concept for the effective tailoring of an uncharged xanthene core-based scaffold/molecular platform toward a specific imaging application using rational design.
Topics: Diamines; Fluorescence; Fluorescent Dyes; Humans; Infrared Rays; Lymph Nodes; Lymphatic Metastasis; Molecular Structure; Optical Imaging
PubMed: 30669835
DOI: 10.1021/acs.analchem.8b05709 -
Journal of the American Chemical Society Sep 2021Carbon capture at fossil fuel-fired power plants is a critical strategy to mitigate anthropogenic contributions to global warming, but widespread deployment of this...
Carbon capture at fossil fuel-fired power plants is a critical strategy to mitigate anthropogenic contributions to global warming, but widespread deployment of this technology is hindered by a lack of energy-efficient materials that can be optimized for CO capture from a specific flue gas. As a result of their tunable, step-shaped CO adsorption profiles, diamine-functionalized metal-organic frameworks (MOFs) of the form diamine-Mg(dobpdc) (dobpdc = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) are among the most promising materials for carbon capture applications. Here, we present a detailed investigation of dmen-Mg(dobpdc) (dmen = 1,2-diamino-2-methylpropane), one of only two MOFs with an adsorption step near the optimal pressure for CO capture from coal flue gas. While prior characterization suggested that this material only adsorbs CO to half capacity (0.5 CO per diamine) at 1 bar, we show that the half-capacity state is actually a metastable intermediate. Under appropriate conditions, the MOF adsorbs CO to full capacity, but conversion from the half-capacity structure happens on a very slow time scale, rendering it inaccessible in traditional adsorption measurements. Data from solid-state magic angle spinning nuclear magnetic resonance spectroscopy, coupled with van der Waals-corrected density functional theory, indicate that ammonium carbamate chains formed at half capacity and full capacity adopt opposing configurations, and the need to convert between these states likely dictates the sluggish post-half-capacity uptake. By use of the more symmetric parent framework Mg(pc-dobpdc) (pc-dobpdc = 3,3'-dioxidobiphenyl-4,4'-dicarboxylate), the metastable trap can be avoided and the full CO capacity of dmen-Mg(pc-dobpdc) accessed under conditions relevant for carbon capture from coal-fired power plants.
Topics: Adsorption; Air Pollutants; Carbon Dioxide; Climate Change; Computer Simulation; Density Functional Theory; Diamines; Metal-Organic Frameworks; Models, Molecular
PubMed: 34491725
DOI: 10.1021/jacs.1c06434 -
Scientific Reports Jan 2021Clinical translation of pluripotent stem cell (PSC) derivatives is hindered by the tumorigenic risk from residual undifferentiated cells. Here, we identified salicylic...
Clinical translation of pluripotent stem cell (PSC) derivatives is hindered by the tumorigenic risk from residual undifferentiated cells. Here, we identified salicylic diamines as potent agents exhibiting toxicity to murine and human PSCs but not to cardiomyocytes (CMs) derived from them. Half maximal inhibitory concentrations (IC) of small molecules SM2 and SM6 were, respectively, 9- and 18-fold higher for human than murine PSCs, while the IC of SM8 was comparable for both PSC groups. Treatment of murine embryoid bodies in suspension differentiation cultures with the most effective small molecule SM6 significantly reduced PSC and non-PSC contamination and enriched CM populations that would otherwise be eliminated in genetic selection approaches. All tested salicylic diamines exerted their toxicity by inhibiting the oxygen consumption rate (OCR) in PSCs. No or only minimal and reversible effects on OCR, sarcomeric integrity, DNA stability, apoptosis rate, ROS levels or beating frequency were observed in PSC-CMs, although effects on human PSC-CMs seemed to be more deleterious at higher SM-concentrations. Teratoma formation from SM6-treated murine PSC-CMs was abolished or delayed compared to untreated cells. We conclude that salicylic diamines represent promising compounds for PSC removal and enrichment of CMs without the need for other selection strategies.
Topics: Animals; Cell Differentiation; Cell Survival; Diamines; Dose-Response Relationship, Drug; Humans; Induced Pluripotent Stem Cells; Mice; Molecular Structure; Myocytes, Cardiac; Oxygen Consumption; Teratoma
PubMed: 33504837
DOI: 10.1038/s41598-021-81351-z -
Nature Communications Dec 2018Over one million tons of CS are produced annually, and emissions of this volatile and toxic liquid, known to generate acid rain, remain poorly controlled. As such,...
Over one million tons of CS are produced annually, and emissions of this volatile and toxic liquid, known to generate acid rain, remain poorly controlled. As such, materials capable of reversibly capturing this commodity chemical in an energy-efficient manner are of interest. Recently, we detailed diamine-appended metal-organic frameworks capable of selectively capturing CO through a cooperative insertion mechanism that promotes efficient adsorption-desorption cycling. We therefore sought to explore the ability of these materials to capture CS through a similar mechanism. Employing crystallography, spectroscopy, and gas adsorption analysis, we demonstrate that CS is indeed cooperatively adsorbed in N,N-dimethylethylenediamine-appended M(dobpdc) (M = Mg, Mn, Zn; dobpdc = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate), via the formation of electrostatically paired ammonium dithiocarbamate chains. In the weakly thiophilic Mg congener, chemisorption is cleanly reversible with mild thermal input. This work demonstrates that the cooperative insertion mechanism can be generalized to other high-impact target molecules.
Topics: Adsorption; Carbon Dioxide; Carbon Disulfide; Diamines; Magnesium; Metal-Organic Frameworks; Models, Chemical; Molecular Structure; Quaternary Ammonium Compounds; Temperature; Thiocarbamates
PubMed: 30510262
DOI: 10.1038/s41467-018-07458-6 -
Nature Communications May 2020Obesity is a health problem affecting more than 40% of US adults and 13% of the global population. Anti-obesity treatments including diet, exercise, surgery and...
Obesity is a health problem affecting more than 40% of US adults and 13% of the global population. Anti-obesity treatments including diet, exercise, surgery and pharmacotherapies have so far failed to reverse obesity incidence. Herein, we target obesity with a pharmacotherapeutic approach that decreases caloric efficiency by mitochondrial uncoupling. We show that a recently identified mitochondrial uncoupler BAM15 is orally bioavailable, increases nutrient oxidation, and decreases body fat mass without altering food intake, lean body mass, body temperature, or biochemical and haematological markers of toxicity. BAM15 decreases hepatic fat, decreases inflammatory lipids, and has strong antioxidant effects. Hyperinsulinemic-euglycemic clamp studies show that BAM15 improves insulin sensitivity in multiple tissue types. Collectively, these data demonstrate that pharmacologic mitochondrial uncoupling with BAM15 has powerful anti-obesity and insulin sensitizing effects without compromising lean mass or affecting food intake.
Topics: Adipose Tissue; Administration, Oral; Animals; Blood Glucose; Body Temperature; Body Weight; Diamines; Diet, Western; Disease Models, Animal; Dose-Response Relationship, Drug; Glucose Clamp Technique; Humans; Insulin Resistance; Liver; Male; Membrane Potential, Mitochondrial; Mice; Mitochondria; Obesity; Oxadiazoles; Oxidative Stress; Pyrazines
PubMed: 32409697
DOI: 10.1038/s41467-020-16298-2