ACS Chemical Health & Safety最新文献

The ambiguity of certain diseases and the potential toxicity of many medications have sparked demand for the incorporation and enhancement of drug delivery systems (DDSs). Nanomedicine has received renewed attention in modern medical advancements with therapeutic uses. Therefore, the development of nanomedicines for enhanced bioaccessibility, long drug administration, and dose reduction has advanced as a unique concept. Nanocapsules, nanoemulsions, drug nanocrystals, micelles, solid lipid nanoparticles (SLNs), and polymeric nanoparticles (poly-NPs) are among the most effective nanomedicine techniques. Poly-NPs have emerged as a potential method to enhance drug pharmacokinetics. Pharmaceutical potency can be increased by using nanocarriers and medication formulations. The potential of poly-NPs to alter contemporary medicine has attracted significant interest; polymer adaptability makes them suitable for site-specific drug delivery requirements. However, little is known about their safety in long-term studies using high-pitched doses. These cells exhibit some extrapyramidal symptoms (EPS) because of the reactivity and size reduction of the polymers chosen by using living cells other than the target. With an increased understanding of polymers and their properties, it is equally important to emphasize the safety and toxicity of DDSs. Some of the toxic effects of polymeric nanodrugs include an increase in the cytotoxicity of the cell, reduction in the feasibility of the cell, increase in the rate of programmed cell death (apoptosis), precursors for tumor formation, DNA destruction, gene toxicity, rupture of the cell membrane, and lipid peroxidation reactions. In this article, we discuss the toxicity of nanoparticles (NPs) used in DDSs, including polylactide-co-glycolide, polylactic acid, polycaprolactone, and poly(alkyl cyanoacrylates), used in DDSs.

Helium is getting more and more difficult to obtain, and it does not look like that will change anytime soon. The only alternative carrier gas to helium that Agilent recommends for gas chromatography mass spectrometry is hydrogen. Converting a gas chromatograph mass spectrometer (GCMS) to use hydrogen presents additional safety concerns and may not be possible for some systems. Helium conservation, having the GCMS system use nitrogen as a carrier gas when idle, may be a viable alternative when conversion to hydrogen is not possible.

Carbon dioxide laser cutters are used to cut and engrave on various types of materials, including metals, wood, and plastics. Although many are equipped with fume extractors for removing airborne substances generated during laser cutting, gases and particulate matter can be released upon opening the lid after completion. This study focused on investigating laser cutting acrylic sheets and associated emissions. Real-time instruments were utilized to monitor both particulate concentrations and size distributions, while the patented Tsai diffusion sampler was used to collect particulate samples on a polycarbonate membrane and transmission electron microscopy (TEM) grid. Identification of released gases consisted of the use of gas sampling with Teflon gas bags followed by analysis using gas chromatography-mass spectrometry (GC-MS). A portable ambient infrared air analyzer was used to quantify the concentrations of the chemicals released by laser cutting activities. The results of the study found that a significant concentration of particulate matter, including nanoplastic particles ranging 15.4–86 nm in particle sizes, and microplastics with agglomerates were released each time the laser cutter lid was opened and were observed to gradually increase in concentration for a period of at least 20 min after the completion of a cut. The GC-MS gaseous samples primarily contained methyl methacrylate at a low level close to the detection limit of the infrared air analyzer.

Field-level exercises with the purpose to assess remediation following the deliberate release of a highly toxic chemical in an indoor environment can be conducted using low(er) toxicity simulants if they are closely linked to the behavior of the toxic chemical itself. Chemical warfare agent (CWA) simulants have been identified on their suitability based on chemical structural similarities and associated physical and chemical properties. However, there are no reported studies that combine measurement of simulant parameters like persistence on surfaces, ability to sample for, and capability to degrade during the decontamination phase such that the level of success of a field-level exercise can be quantified. Experimental research was conducted to assess these gaps using a select number of CWA simulants. The organophosphate pesticide malathion was found to be a suitable simulant for use in field-level exercises that simulate the release of the highly persistent nerve agent VX based on its high persistence, effective surface sampling and analysis using standard analytical equipment, and the in situ degradation in the presence of different oxidizing decontaminants.

In recent years, chemical laboratory accidents have frequently occurred in Chinese universities. A three-year safety inspection by the Ministry of Education of China discovered many issues in university chemical laboratories, including inadequate hazards identification, limited risk awareness, and insufficient safety management. In view of these problems, this study established the inherent hazards assessment and classification (IHAC) method for university chemical laboratories. We quantitatively evaluated the materials, equipment, and processes of chemical laboratories for inherent hazards. To differentiate levels of supervision over inherent hazards, we separated chemical laboratories into four tiers: A, B, C, and D. We used IHAC in a Chinese university’s chemical laboratory to show that it can effectively identify and evaluate laboratory dangers. Simultaneously, splitting laboratories into multiple levels can result in more targeted laboratory safety management and accident prevention.

The formation mechanism of boron subphthalocyanines (BsubPcs) has thus far evaded researchers, making it nearly impossible to accurately estimate the overall reaction enthalpy─a critical metric for determining chemical process safety for scale-up. To address this gap, reaction calorimetry was used to collect thermokinetic data for a baseline Br-BsubPc reaction at three temperatures and two BBr₃ reagent ratios and a proposed semibatch process for Cl-BsubPc. For the Br-BsubPc process, the magnitude of the enthalpy of reaction (ΔH_r) increased with increasing reaction temperature, from −244.6 kJ/mol-BBr₃ at 25 °C to −332.7 kJ/mol-BBr₃ at 50 °C to −391.3 kJ/mol-BBr₃ at 75 °C. However, this increase in the magnitude of ΔH_r did not result in a noticeable increase in Br-BsubPc yield, achieving 50%, 49%, and 52% yields at 25 °C, 50 °C, and 75 °C, respectively. When the molar equivalence of BBr₃ was increased by 1.5× at 25 °C, the magnitude of ΔH_r increased slightly (−252.2 kJ/mol-BBr₃), but the yield did not improve (47%). Therefore, further attempts were made to try and improve the yield of Br-BsubPc by increasing the molar equivalence of BBr₃. It was found that BBr₃ equivalencies greater than 0.48 resulted in significant reductions in Br-BsubPc yield. The ΔH_r of the semibatch Cl-BsubPc process was −266.5 kJ/mol-BCl₃ with a yield of 33%. These processes were assessed based on criticality criteria and were both found to be “Criticality Class 1”, which is relatively safe for scale-up. Based on the calorimetry measurements, preliminary estimates for process conditions and reactor design for scale-up are provided.

Objectives: N₂O is widely used in the chemical industry and laboratories; however, several fire/explosion accidents have been reported in facilities that handle N₂O. This study aimed (i) to experimentally investigate the lower and upper flammability limits (LFL and UFL, respectively), limit nitrous oxide concentration (LN₂OC), and minimum inerting concentrations (MICs) of fuel–N₂O–diluent mixtures and (ii) to computationally estimate the UFLs of fuel–N₂O–diluent mixtures. Methods: Herein, methane and n-propane and nitrogen (N₂), argon (Ar), and carbon dioxide (CO₂) were used as fuels and diluents, respectively. The LFL, UFL, LN₂OC, and MICs of the fuel–N₂O–diluent mixtures were experimentally determined using a closed cylindrical vessel, and their UFLs were computationally estimated based on the laws of conservation energy and mass and adiabatic flame temperatures. Results: Flammability-limit experiments revealed the following: (i) the LFLs of the CH₄–N₂O–diluent and C₃H₈–N₂O–diluent mixtures were 2.5 and 1.4 vol %, respectively, (ii) the UFLs of the CH₄–N₂O–diluent and C₃H₈–N₂O–diluent mixtures were 40.5 and 24.0 vol %, respectively, (iii) a nearly linear relationship between the UFL and diluent concentration was found, and (iv) the order of MICs in N₂O atmosphere was consistent with the inerting ability of the diluents. Calculations based on overall combustion reactions and the laws of energy and mass conservation using six and five chemicals successfully estimated the UFLs of the CH₄–N₂O–diluent and C₃H₈–N₂O–diluent mixtures with mean absolute percentage errors of ≤2.8% and ≤4.1%, respectively. Conclusions: The semiempirical model suggested herein allows accurate estimation of the UFLs of the tested fuel–N₂O–diluent mixtures. These findings would contribute to reducing accident-induced losses in the chemical industry and laboratories handling N₂O.

Researchers have the potential to be exposed to a wide variety of hazards inherent to the equipment they use and maintain. When equipment does not function as expected, researchers sometimes reach out to their vendors for assistance. Early diagnostic or troubleshooting interactions between researcher and vendor are often conducted over the telephone and can lead to researchers performing work outside of their area of expertise and exposure to unknown hazards. This type of interaction significantly contributed to an incident where during diagnostic activities a researcher accidentally contacted, and discharged, a capacitor in an X-ray diffraction instrument. While this incident did not produce a serious injury, if the capacitor discharge path had occurred hand-to-hand across the heart, a serious injury may have been possible.