Manufacture Of Consumer Products Research Articles

Ubiquitous occurrence of 1,4-dioxane in drinking water of China and its ecological and human health risk

The occurrence and distribution of 1,4-dioxane was investigated in 280 source and finished drinking water samples from 31 Chinese cities, based on which its ecological and health risks were systematically evaluated. The findings demonstrated that 1,4-dioxane was detected in about 80.0 % samples with values ranging from n.d. to 7757 ng/L in source water and n.d. to 2918 ng/L in drinking water. 1,4-Dioxane showed limited removal efficiency using conventional coagulation–sedimentation–filtration processes (14 % ± 48 %), and a removal efficiency of 35 % ± 44 % using ozonation-biological activated carbon advanced treatment processes. Relatively higher concentrations, detection frequency and environmental risk were observed in Taihu Lake, Yellow River, Yangtze River, Zhujiang River, and Huaihe River mainly in the eastern and southern regions, where there are considerable industrial activities and comparatively high population densities. The widespread presence as by-products during manufacturing consumer products e.g., ethoxylated surfactants, suggested municipal wastewater discharges were the dominant source for the ubiquitous occurrence of 1,4-dioxane, while industrial activities, e.g. resin manufacturing, also contribute considerably to the elevated concentrations of 1,4-dioxane. The estimated risk quotients were in the range of <1.5 × 10−4 for ecological risk, <5.0 × 10−3 by oral exposure and < 5.0 × 10−2 by inhalation exposure for health risk, illustrating limited ecological harm to water environment or chronic toxicity to human health. For carcinogenic risk, 1,4-Dioxane presented a mean risk of 1.8 × 10−6 by oral exposure, which slightly surpassed the recommended acceptable levels of U.S. EPA (<10−6), and risk from inhalation exposure could be negligible. The pervasiveness in drinking water, low removal efficiencies during water treatment processes, and suspected health impacts, highlighted the necessity to set related water quality standards of 1,4-dioxane in order to improve water environment in China.

A miniaturized stir bar sorptive dispersive microextraction method for the determination of bisphenols in follicular fluid using a magnetic covalent organic framework

BackgroundBisphenols, particularly bisphenol A (BPA), are the primary monomers used as additives in the manufacturing of many consumer products. The exposure to these compounds is related to endocrine-disrupting and reproductive effects, among others. For this reason, the development of analytical methods for their determination in biological matrixes is needed to monitor the population exposure to these compounds. Their quantification at ovarian level (i.e., follicular fluid) is interesting for the assessment of the bisphenol content to draw conclusions about infertility problems. However, the background does not meet all requirements by focusing mainly on BPA. ResultsIn this work, a miniaturized stir bar sorptive dispersive microextraction (mSBSDME) approach has been developed for the determination of BPA and eight analogues in follicular fluid. In the proposed method, the sample is previously cleaned-up using a zirconia-based solid-phase extraction cartridge, removing proteins and phospholipids, and then subjected to the mSBSDME for the preconcentration of the analytes. For this purpose, a magnetic covalent organic framework was used as sorbent. A Plackett-Burman design was applied to select the significant variables affecting the mSBSDME. Afterwards, the only significant variable (i.e., sorbent amount) was optimized. Under the optimized conditions, the proposed method was properly validated, and satisfactory analytical parameters in terms of linearity (up to 50 ng mL−1), enrichment factors (8.5–14.3), limits of detection in the low ng mL−1 range, and precision (relative standard deviations below 11.5 %) were obtained. Finally, the method was successfully applied to five samples, detecting BPA and other two analogues. SignificanceThis method expands the potential applicability of the mSBSDME to other low-availability complex matrixes, which would otherwise be difficult to analyze. Moreover, it offers a valuable tool for monitoring the female population's exposure to bisphenols with the final aim of evaluating if infertility problems of women might be associated to the exposure to these highly endocrine disrupting compounds.

Environmental sustainability evaluation of glycerol and propylene-based pathways to acrylic acid via different intermediates

Acrylic acid is an important industrial chemical used for the manufacturing of many consumer products. It is currently produced using fossil fuel-based propylene via acrolein intermediate. However, it can be...

Effects of shear-induced crystallization on the complex viscosity of lamellar-structured concentrated surfactant solutions.

Material relationships at low temperatures were determined for concentrated surfactant solutions using a combination of rheological experiments, cross-polarized microscopy, calorimetry, and small angle X-ray scattering. A lamellar structured 70 wt% solution of sodium laureth sulfate in water was used as a model system. At cold temperatures (5 °C and 10 °C), the formation of surfactant crystals resulted in extremely high viscosity. The bulk flow behavior of multi-lamellar vesicles (20 °C) and focal conic defects (90 °C) in the lamellar phase was similar. Shear-induced crystallization at temperatures higher than the equilibrium crystallization temperature range resulted in an unusual complex viscosity peak. The effects of processing-relevant parameters including temperature, cooling time, and applied shear were investigated. Knowledge of key low-temperature structure-property-processing relationships for concentrated feedstocks is essential for the sustainable design and manufacturing of surfactant-based consumer products for applications such as cold-water laundry.

The role of the aryl hydrocarbon receptor in mediating the effects of mono(2-ethylhexyl) phthalate in mouse ovarian antral follicles†.

Di(2-ethylhexyl) phthalate (DEHP) is a pervasive environmental toxicant used in the manufacturing of numerous consumer products, medical supplies, and building materials. DEHP is metabolized to mono(2-ethylhexyl) phthalate (MEHP). MEHP is an endocrine disruptor that adversely affects folliculogenesis and steroidogenesis in the ovary, but its mechanism of action is not fully understood. Thus, we tested the hypothesis that the aryl hydrocarbon receptor (AHR) plays a functional role in MEHP-mediated disruption of folliculogenesis and steroidogenesis. CD-1 mouse antral follicles were isolated and cultured with MEHP (0-400μM) in the presence or absence of the AHR antagonist CH223191 (1μM). MEHP treatment reduced follicle growth over a 96-h period, and this effect was partially rescued by co-culture with CH223191. MEHP exposure alone increased expression of known AHR targets, cytochrome P450 (CYP) enzymes Cyp1a1 and Cyp1b1, and this induction was blocked by CH223191. MEHP reduced media concentrations of estrone and estradiol compared to control. This effect was mitigated by co-culture with CH223191. Moreover, MEHP reduced the expression of the estrogen-sensitive genes progesterone receptor (Pgr) and luteinizing hormone/choriogonadotropin receptor (Lhcgr) and co-treatment with CH223191 blocked this effect. Collectively, these data indicate that MEHP activates the AHR to impair follicle growth and reduce estrogen production and signaling in ovarian antral follicles.

Ocular irritation reversibility assessment of a laundry detergent using the Porcine Corneal Opacity Reversibility Assay (PorCORA): a focused study

Consumer product manufacturers utilise a spectrum of alternative ocular irritation assays, as these tests do not require the use of live animals. Despite their usefulness, no regulatory-accepted assay assesses the reversibility of ocular damage, a key criterion of GHS ocular classification, like the rabbit eye test (i.e., Draize Rabbit Eye Test [DRET]) . The Porcine Corneal Opacity Reversibility Assay (PorCORA), an ex vivo intact corneal tissue culture model, predicts the reversibility of damage by ocular irritants. Inclusion of the damage reversibility endpoint in the PorCORA supplements other alternative test methods for ocular irritation, by assessing induced eye damage and the ability of this damage to reverse (heal) without the use of live animals to distinguish between Globally Harmonised System of Classification and Labelling of Chemicals (GHS) ocular classifications. In this focused study, results of a Bovine Corneal Opacity and Permeability (BCOP) test of a laundry detergent, neat and 10% dilution, (product mixture from S.C. Johnson & Son, Inc. [SCJ]) classified the product into GHS Category 1; however, the BCOP test cannot assess the reversibility of ocular damage. The laundry detergent was evaluated using the PorCORA, where ocular damage induced by the detergent was fully reversed within seven days. Evaluation of the reversibility of ocular damage using the PorCORA in this focused study can add strength to the weight-of-evidence (WoE) analysis approach in ocular hazard assessment. This WoE approach strengthens the argument that the PorCORA can be used to supplement BCOP data, and that this laundry detergent is not an irreversible eye irritant.

In Vitro Effects of Bisphenol Analogs on Immune Cells Activation and Th Differentiation.

Investigate the immunomodulatory effects of bisphenols in the THP-1 cell line and peripheral blood mononuclear cells in response to lipopolysaccharide (LPS) activation or to phorbol 12-myristate 13-acetate (PMA) and ionomycin. We have previously demonstrated the usefulness of the evaluation of RACK1 expression as a link between endocrine disrupting activity and the immunotoxic effect of xenobiotics. We demonstrated that while BPA and BPAF reduced RACK1 expression, BPS was able to increase it. Bisphenol A (BPA) is one of the most commonly used chemicals in the manufacturing of polycarbonate plastics and plastic consumer products. Its endocrine disrupting (ED) potential and changes in European regulations have led to replacing BPA in many uses with structurally similar chemicals, like bisphenol AF (BPAF) and bisphenol S (BPS). However, emerging data indicated that bisphenol analogues may not be safer than BPA both in toxic effects and ED potential. THP-1 cell line and peripheral blood mononuclear cells were activated with lipopolysaccharide (LPS) or with phorbol 12-myristate 13-acetate (PMA) and ionomycin. BPA and BPAF decreased LPS-induced expression of surface markers and the release of pro-inflammatory cytokines, while BPS increased LPS-induced expression of CD86 and cytokines. BPA, BPAF, and BPS affected PMA/ionomycin-induced T helper differentiation and cytokine release with gender-related alterations in some parameters investigated. Data confirm that bisphenols can modulate immune cell differentiation and activation, further supporting their immunotoxic effects.

Synthesis And Applications of Bisphenol-A Epoxide Resins - A Review

Epoxy resin is a widely used substance for coatings, adhesives, composites, electrical components, LEDs, paintbrush manufacturing, fiber-reinforced plastic materials, and consumer product manufacturing (such as cases, kits, and snowboards). Epoxy resin is highly versatile due to its properties. One of the most commonly used types of epoxy resin is Bisphenol-A Epoxy resin, which is excellent for high-temperature applications, the adhesion of a variety of substrates, compression, bends, electrical insulation, mortar, grouts, adhesion, and high-tensile-strength applications. There are several types and applications of Bisphenol-A epoxy resin. This paper aims to review the types, synthesis, and applications of Bisphenol-A epoxy resin.

Mechanistic approach on comparative biosorption of dyes by extracellular polymer of Ochrobactrum pseudintermedium C1 utilizing waste mineral lubricating oil

Dyes are widely used in manufacturing of various consumer products for their ability to impart characteristic color. However, dyes are also one of the most important hazardous pollutants in this present day. Presence of hydroxyl, phosphate, ether, carbonyl and alkyl groups also enable bacterial extracellular polymers to function as biosorbent. In this study, negatively charged biosorbent EP-C1 produced by Gram-negative bacterium Ochrobactrum pseudintermedium C1 utilizing waste mineral lubricating oil has given different decolorization percentages for triphenylmethane cationic Malachite Green and azoic anionic Congo Red at neutral pH. Time wise absorbances from Ultraviolet-Visible Spectrophotometry has estimated maximum biosorption of Malachite Green after 300 min. Biosorption capacities have differed with initial dye concentrations, biosorbent dosages and contact time. Time taken by each dye to reach saturation has depended upon their charged bearing groups of each dye and biosorbent. Kinetic (pseudo first and pseudo second order) and diffusion (intra particle and liquid film) parameters in presence of different dye concentrations and biosorbent dosages were studied for understanding the biosorption mechanism. Morphological differences in chemical structure, chemical functional groups of EP-C1 and EP-C1 loaded dye was studied by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Zeta potential measurements. A compiled overview on comparative mechanistic biosorption of Malachite Green and Congo Red dyes by a bacterial extracellular polymer in miniature laboratory shake flask experiments was done in this study. Newer advents on biological remediation of dyes with mineral lubricating oil as sole carbon source can add a new feather to the already available bioremediation techniques in mitigation of hazardous wastes.

Pengaruh Firm Size, Likuiditas, Leverage Dan Profitabilitas Terhadap Nilai Perusahaan Pada Perusahaan Manufaktur Sub Sektor Barang Konsumsi Yang Terdaftar Di Bursa Efek Indonesia

This study examines how business size, liquidity, leverage, and profitability affect firm value in Indonesia Stock Exchange-listed supply products manufacturing companies between 2019 and 2021. Earlier corporate value study had mixed results. Therefore, more research is needed to retest company worth. The survey sampled 47 consumer products manufacturers. For the three-year observation period (2019–2021), 13 business samples were purposefully sampled with 39 observations. The Indonesian Stock Exchange website provided the sample businesses and research data. Research data obtained from the Indonesian Stock Exchange website, where sample businesses were found. The data analysis approach began with descriptive statistics, classical assumption test, multiple regression analysis, and hypothesis testing. Corporate size, liquidity, leverage, and profitability affect firm value. According to research, only profitability increases firm worth significantly. Significant to firm value. Liquidity boosts corporate value but not significantly. Leverage and firm size have minimal impact on firm value

Legacy and emerging per- and polyfluoroalkyl substances (PFAS) regulate steroidogenesis in the male gonad.

Per- and polyfluoroalkyl substances (PFAS) are widely used in a variety of industrial processes and manufacturing of consumer products. Current efforts by the manufacturing industry will limit use of long-chain or legacy PFAS represented by perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) and replace with short-chain or emerging PFAS such as perfluorobutanoic acid (PFBA) and perfluorobutane sulfonic acid (PFBS). However, there is little to no information on the toxicity of new and emerging PFAS. Therefore, we performed experiments in growing Long-Evans male rats to investigate effects of low dose prepubertal and pubertal exposures to PFAS on gonadal steroid hormone secretion. The results demonstrated that both legacy and emerging PFAS have the capacity to regulate testicular steroidogenesis. For example, prepubertal exposures to PFOS, PFBA and PFBS increased serum and testicular T concentrations. Exposure to PFBA increased testicular E2 concentrations and PFOS and PFBS both decreased serum E2 concentrations while stimulating testicular E2 secretion. The data also demonstrated additive effects due to legacy and emerging PFAS mixtures compared to the individual chemicals. The gonadal effects due to PFAS exposures occurred at nanomolar concentrations, which approximate PFAS levels in the environment. Taken together, the present study support the need for development of cost-effective and sustainable filtration media for different processes to remove PFAS from water and other sources of exposure. Current action by regulatory agencies such as the US Environmental Protection Agency to limit use of PFAS in the manufacture of consumer products will protect public health.

Bisphenol A increases the size of primary mammary tumors and promotes metastasis in a murine model of breast cancer

Triple negative breast cancer (TNBC) is a subtype of breast tumor characterized for the absence of estrogen and progesterone receptors expression and low HER2/neu expression. Bisphenol A (BPA) is an endocrine disrupting chemical with estrogenic activity that has been associated with increasing rates of breast cancer. Moreover, BPA is a solid organic synthetic chemical employed in the manufacture of many consumer products, epoxy resins and polycarbonate plastics including baby bottles, containers for food and beverages, and the lining of beverage cans. The G-protein-coupled estrogen receptor (GPER) is activated by endogenous hormones and synthetic ligands, such as BPA. GPER is expressed in TNBC cells and its expression is associated with larger tumor size, metastasis and worse survival prognosis. In breast cancer cells, BPA induces activation of signal transduction pathways that mediates migration and invasion via GPER in human TNBC MDA-MB-231 cells. In this study, we demonstrate that BPA induces an increase of GPER expression and its translocation from cytosol to cytoplasmic membrane, metalloproteinase (MMP)-2 and MMP-9 secretion, migration and invasion in murine TNBC 4T1 cells. In a murine TNBC model “in vivo” using 4T1 cells, BPA induces the formation of mammary tumors with more weight and volume, and an increase in the number of mice with metastasis to lung and nodules in lung compared with tumors and metastasis to lung of untreated Balb/cJ mice. In conclusion, our findings demonstrate that BPA mediates the growth of mammary primary tumors and metastasis to lung in a murine model of breast cancer.

Bisphenol S Reduces Pig Spermatozoa Motility through Different Intracellular Pathways and Mechanisms than Its Analog Bisphenol A.

Bisphenol A (BPA: 2,3-bis (4-hydroxyphenyl) propane) is an environmental chemical widely used in the manufacturing of epoxy polymers and many thermoplastic consumer products. Serious concerns about its safety led to the development of analogs, such as BPS (4-hydroxyphenyl sulfone). Very limited studies about BPS's impact on reproduction, specifically in spermatozoa, exist in comparison with BPA. Therefore, this work aims to study the in vitro impact of BPS in pig spermatozoa in comparison with BPA, focusing on sperm motility, intracellular signaling pathways and functional sperm parameters. We have used porcine spermatozoa as an optimal and validated in vitro cell model to investigate sperm toxicity. Pig spermatozoa were exposed to 1 and 100 μM BPS or BPA for 3 and 20 h. Both bisphenol S and A (100 μM) significantly reduce pig sperm motility in a time-dependent manner, although BPS exerts a lower and slower effect than BPA. Moreover, BPS (100 μM, 20 h) causes a significant increase in the mitochondrial reactive species, whereas it does not affect sperm viability, mitochondrial membrane potential, cell reactive oxygen species, GSK3α/β phosphorylation or phosphorylation of PKA substrates. However, BPA (100 μM, 20 h) leads to a decrease in sperm viability, mitochondrial membrane potential, GSK3β phosphorylation and PKA phosphorylation, also causing an increase in cell reactive oxygen species and mitochondrial reactive species. These intracellular effects and signaling pathways inhibited might contribute to explaining the BPA-triggered reduction in pig sperm motility. However, the intracellular pathways and mechanisms triggered by BPS are different, and the BPS-caused reduction in motility can be only partially attributed to an increase in mitochondrial oxidant species.

Assessing the Biodegradability of PHB-Based Materials with Different Surface Areas: A Comparative Study on Soil Exposure of Films and Electrospun Materials.

Due to the current environmental situation, biopolymers are replacing the usual synthetic polymers, and special attention is being paid to poly-3-hydroxybutyrate (PHB), which is a biodegradable polymer of natural origin. In this paper, the rate of biodegradation of films and fibers based on PHB was compared. The influence of exposure to soil on the structure and properties of materials was evaluated using methods of mechanical analysis, the DSC method and FTIR spectroscopy. The results showed rapid decomposition of the fibrous material and also showed how the surface of the material affects the rate of biodegradation and the mechanical properties of the material. It was found that maximum strength decreased by 91% in the fibrous material and by 49% in the film. Additionally, the DSC method showed that the crystallinity of the fiber after exposure to the soil decreased. It was established that the rate of degradation is influenced by different factors, including the surface area of the material and its susceptibility to soil microorganisms. The results obtained are of great importance for planning the structure of features in the manufacture of biopolymer consumer products in areas such as medicine, packaging, filters, protective layers and coatings, etc. Therefore, an understanding of the biodegradation mechanisms of PHB could lead to the development of effective medical devices, packaging materials and different objects with a short working lifespan.

A Scoping Review: Scoping Review: Appropriate Big Ideas of Nanoscience and Nanotechnology to Teach in Chemistry for Secondary School

In the last decade, the nanotechnology sector is rising to take over the manufacturing of consumer products including pharmaceuticals. Due to the rapid advancement of nanotechnology, Malaysia has also taken the lead by introducing nanotechnology to Form Five students in 2021 following the revision of curricula in 2017. While research on which big ideas in nanotechnology to teach is still lacking around the world, the goal of this scoping review was to identify appropriate big ideas of nanotechnology to include in the secondary school curriculum, as well as students' and teachers' perspectives on teaching and learning nanotechnology using the Model of Educational Reconstruction (MER). The scoping review was conducted by adopting a framework with five stages which are (1) identifying the research question, (2) identifying relevant studies, (3) study selection, (4) charting the data, and (5) collating, summarizing, and reporting the results. From the 30 pertinent articles included in this paper, it was found that big ideas that were used in many of the included articles are size and scale, self-assembly, size-dependent properties, volume-to-surface area concept, and applications of nanotechnology. Students were most likely to perform well when they are given tasks after learning nanotechnology with one or two of the big ideas of nanotechnology. Students gave positive feedback when they learned this unit with hands-on activities, using models, and when they attend nanotechnology conferences, whereas teachers wanted more courses on teaching nanotechnology to be provided because most science teachers were trained before nanotechnology was included in science teachers' educational program. Overall, experts feel that while deciding the big ideas of nanotechnology to teach, teachers' perspectives on the appropriateness of nanotechnology's insertion point into the current curriculum should be considered.

The tissue dust analysis system: a new device and methodology to quantify dusting and linting propensity in hygiene tissue papers

Paper dusting, which occurs when a tissue web releases unbound and loosely bound fibers or filler particles during tissue-making or product manufacturing, has an overall negative impact, causing safety hazards, machine runnability difficulties, and product quality issues. To date, there are no well-established industry standards to quantify dusting/linting propensities in finished tissue products, thus evaluating the effectiveness of dust/lint control programs is challenging yet intriguing. This research aims to fill this gap by developing a methodology to characterize dusting in tissue papers. We have developed a device prototype (named the Tissue Dust Collector) and a methodology that together have been named the Tissue Dust Analysis System (TDAS), which aims at quantifying the propensity for tissue-grade paper products to generate dust/lint in a controlled and reproducible manner. Two samples, corresponding to commercial products with a low and high linting propensity, were tested using the proposed device and methodology, and the released particles were quantified and characterized. The device and methodology provided reproducible results for simulated consumer handling and product manufacturing scenarios. By changing the instrument's motor frequency, the force of agitation changes, mimicking/simulating consumer (60 strokes per min, spm) and producer/manufacturing (180 spm) handling scenarios (though manufacturing processes are much faster in practice). Particle counts at each level for each product showed reproducible values differentiable at different agitation levels. Adopting the proposed Tissue Dust Analysis System may help to characterize and understand the mechanisms behind dusting to create dust-control strategies that can alleviate this issue at its various sources or simply allow tissue paper manufacturers to compare and advertise their products based on dusting propensity.

Effects of Selected Metal Nanoparticles (Ag, ZnO, TiO2) on the Structure and Function of Reproductive Organs.

Various studies have shown that the reproductive organs are highly sensitive to toxic elements found in the environment. Due to technological progress, the use of nanoparticles has become more common nowadays. Nanoparticles are used for drug delivery because their dimensions allow them to circulate throughout the body and enter directly into the cell. Antimicrobial properties are increasingly used in the manufacture of medical devices, textiles, food packaging, cosmetics, and other consumer products. Nanoparticles provide several benefits, but aspects related to their effects on living organisms and the environment are not well known. This review summarizes current in vivo, and in vitro animal studies focused on the evaluation of toxicity of selected metal nanoparticles (Ag, ZnO, TiO2) on male and female reproductive health. It can be concluded that higher concentrations of metal nanoparticles in the male reproductive system can cause a decrease in spermatozoa motility, viability and disruption of membrane integrity. Histopathological changes of the testicular epithelium, infiltration of inflammatory cells in the epididymis, and prostatic hyperplasia have been observed. Nanoparticles in the female reproductive system caused their accumulation in the ovaries and uterus. Metal nanoparticles most likely induce polycystic ovary syndrome and follicular atresia, inflammation, apoptosis, and necrosis also occurred.

Comparing the effects of bisphenol A, C, and F on bovine theca cells in vitro

Endocrine disrupting chemicals (EDCs) target aspects of hormone activity. Tightly coordinated crosstalk between two somatic cells of the ovary, granulosa and theca cells, governs steroid hormone production and plays a critical role in reproduction. It is thus pertinent to understand the impact of EDCs on granulosa and theca cells. Bisphenol A (BPA), a well-known EDC, is widely used in the manufacturing of consumer products with humans routinely exposed. Strong evidence of the adverse effects of BPA on the female reproductive system has emerged and as a result, manufacturers have begun replacing BPA with other bisphenols, such as BPC and BPF. The safety of these analogs is currently unclear and should be investigated independently. Although much is known about the impact of BPA on granulosa cells, similar study of theca cells has been neglected. Further, there is a lack of studies on the impact of BPC and BPF on the female reproductive system. To fill these gaps, the present study compared the effect of BPA, BPC, and BPF on the viability and steroid production of theca cells from bovine, a clinically relevant model for human reproduction. We show that BPC is more detrimental to theca cell viability and progesterone production compared to BPA. Surprisingly, we also found that BPF induces an increase in progesterone production compared to a decrease with BPA and BPC. To determine safety for the reproductive system, we conclude that a major shift away from BPA to bisphenol analogs should be investigated more thoroughly.

Measurement of polystyrene photodegradation rate using a quartz crystal microbalance.

Polystyrene is a very popular polymer utilised in the manufacture of various consumer products. This polymer is very cheap; however, after its usage, the slowness of its photodegradation leads to environmental pollution. In this report, the author presents a technique to systematically measure the rate of photodegradation of a thin polystyrene film. The said film was made to coat a quartz crystal microbalance (QCM) sensor. In order to detect polymer degradation and the reduction in the molecular weight, the resonance frequency of the sensor was monitored for 24 h. Results revealed that QCM sensor irradiation with ultraviolet light with a wavelength of 365 nm and optical power of 1.5 mW caused a quite significant change in the polymer structure.

Mediation by hormone concentrations on the associations between repeated measures of phthalate mixture exposure and timing of delivery.

Background:Phthalates are used in manufacturing of consumer products, resulting in ubiquitous human exposure to phthalate mixtures. Previous work has suggested that phthalates display endocrine disrupting capabilities, and exposure is associated with early delivery.Objective:To assess mediating effects of hormone concentrations on associations between phthalate mixtures and preterm birth (PTB).Methods:Repeated urinary phthalates and serum hormones were measured among 1011 women in the PROTECT Puerto Rico birth cohort from 2011–2019. We utilized ridge regression to create phthalate environmental risk scores (ERS), which represent weighted summaries of total phthalate exposure. Mediation analyses were conducted on a subset of 705 women. We additionally conducted fetal sex-specific analyses.Results:Free thyroxine (FT4) mediated 9.6% of the association between high molecular weight (HMW) ERS at 18 weeks and reduced gestational age at delivery (95%CI:1.07–29.9). Progesterone at 26 weeks mediated 21.1% and 16.2% of the association between HMW ERS at 18 and 22 weeks, and spontaneous PTB, respectively. Among male fetuses, corticotropin releasing hormone (CRH) at 18 weeks mediated 28.2% of the association between low molecular weight ERS and spontaneous PTB.Significance:We provide introductory evidence of hormone disruption on the causal pathway between phthalate exposure and early delivery. We also show differences by fetal sex, but a larger sample size is necessary to validate our findings.