Chlorella filled poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend bio-composites compatible with additive manufacturing processes: Fluorescent and anti-counterfeiting QR codes applications.

Anti-counterfeiting in 3D printing has gained significant attention, however, current approaches often fall short of fully capitalizing on the inherent advantages of personalized manufacturing with this technology. Herein, we propose an embedded anti-counterfeiting scheme for additive manufacturing, accompanied by a novel fluorescent encrypted quick response (QR) method. This approach involves the development of a 3D printing filament utilizing poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) bio-composites as the primary filament matrix, with varying quantities of Chlorella powder incorporated. The resulting filament has a good thermal stability near 200 °C and exhibits a distinctive red fluorescence under ultraviolet light, with the emission peak at 677 nm when excited by 415 nm blue light. Fluorescence imaging analysis confirms that the red fluorescence in 3D printed devices containing Chlorella is a result of the chlorophyll and its derivatives fluorescence effect. The fluorescent encrypted QR codes are inconspicuous in daylight but become easily discernible under ultraviolet light. In the cases of recognizable QR codes, the ∆Eab* values all exceed 35, and the LC/LB values deviate significantly from 1. This research delves into the fluorescence characteristics of Chlorella and highlights its applicability in 3D printing, specifically within the realm of product anti-counterfeiting, presenting a groundbreaking approach.

Recycled PET/PA6 Fibers from Waste Textile with Improved Hydrophilicity by In-Situ Reaction-Induced Capacity Enhancement.

Due to the increasing amounts of textile waste, textile to textile recycling is of prime concern. Polyethylene terephthalate (PET) represents the most extensively used type of chemical fiber. Its spinnability suffers from impurities and degradation in the processing, which limits its recycling to new fibers. Here, recycled polyester is blended with a small amount of recycled nylon, and the regenerated fibers, which demonstrated good mechanical properties, were obtained via a melt spinning machine. The mechanical properties, thermal properties, rheological properties, and chemical structure of the modified recycled fibers were investigated. It was found that when compared with rPET-T fibers, the elongation at break of rPET-Ax fibers increased to 17.48%, and the strength at break decreased to 3.79 cN/dtex. The compatibility of PET and PA6 copolymer were enhanced by copolymers produced by in-situ reaction in the processing. Meanwhile, the existence of PA6 increases the crystallization temperature and improves the hydrophilicity of the fibers. This study realized the high-value recycling of waste PET fabric to new fibers, which opens a door for the large utilization of waste textiles.

Application of 3D printing technology for green synthesis of Fe2O3 using ABS/TPU/chlorella skeletons for methyl orange removal.

Photocatalysis is widely acknowledged as an efficient and environmentally friendly method for treating dye-contaminated wastewater. However, the utilization of powdered photocatalysts presents significant challenges, including issues related to recyclability and the potential for secondary pollution. Herein, a novel technique based on 3D printing for the synthesizing of iron oxide (Fe2O3) involving chlorella was presented. Initially, chlorella powders were immobilized within acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) substrate plastics using melt extrusion technology. Subsequently, these composite materials were transformed into ABS/TPU/chlorella skeletons (ATCh40), through fused deposition molding (FDM) technology. The integration of Fe2O3 onto the ATCh40 (ATCh40-Fe2O3) skeletons was accomplished by subjecting them to controlled heating in an oil bath. A comprehensive characterization of the synthesized materials confirms the successful growth of Fe2O3 on the surface of 3D skeletons. This strategy effectively addresses the immobilization challenges associated with powdered photocatalysts. In photocatalytic degradation experiments targeting methyl orange (MO), the ATCh40-Fe2O3 skeletons exhibited a remarkable MO removal rate of 91% within 240 min. Under conditions where the pH of MO solution was maintained at 3, and the ATCh40-Fe2O3 skeletons were subjected to a heat treatment in a 150 °C blast drying oven for 2 hours, the degradation rate of MO remained substantial, achieving 90% removal after 6 cycles. In contrast, when the same synthetic procedure was applied to ABS/TPU (AT) skeletons, the resulting product was identified as α-FeOOH. The MO removal rate by the AT-α-FeOOH skeletons was considerably lower, reaching only 49% after 240 min. This research provided a practical approach for the construction of photocatalytic devices through the use of 3D printing technology.

3D printed cylindrical capsules as a Chlorella pyrenoidosa immobilization device for removal of lead ions contamination.

Immobilization is considered as a promising strategy toward the practical applications of powdered adsorbent. Herein, three dimensional (3D) printing cylindrical capsules with cross-linked PVA hydrogels membrane in encapsulate Chlorella pyrenoidosa (Cp) were utilized for removal of lead ions. The chemical compositions, hydrogels performance and morphologies of the membranes were determined by Fourier transformed infrared spectroscopy (FTIR), cross-linking degree, swelling degree, membrane flux and scanning electron microscopy (SEM). It is found that PVA cross-linking structure is successfully synthesized on the surface of capsule body and cap due to the presence of PVA in the filament. The lead ions adsorption capacity related to initial concentration of 50 mg/L in 48 h is reached 75.61%, revealing a good removal ability. The self-floating 3D printed capsules device also shows an excellent recovering property. After 7 runs of adsorption experiment, the lead ions adsorption ratio remains 78.56%, which will bring a broad prospect in wastewater treatment, chemical slow release along with sample preparation and separation.

Selective Decomposition of Waste Rubber from the Shoe Industry by the Combination of Thermal Process and Mechanical Grinding.

A major challenge in waste rubber (WR) industry is achieving a high sol fraction and high molecular weight of recycled rubber at the same time. Herein, the WR from the shoe industry was thermo-mechanically ground via the torque rheometer. The effect of grinding temperature and filling rate were systematically investigated. The particle size distribution, structure evolution, and morphology of the recycled rubber were explored by laser particle size analyzer, Fourier transform infrared spectroscopy (FTIR), sol fraction analysis, gel permeation chromatography (GPC), differential scanning calorimeter (DSC), and scanning electron microscope (SEM). The results indicate that the thermo-mechanical method could reduce the particle size of WR. Moreover, the particle size distribution of WR after being ground can be described by Rosin's equation. The oxidation reaction occurs during thermal-mechanical grinding. With the increase of the grinding temperature and filling rate, the sol fraction of the recycled WR increases. It is also found that a high sol fraction (43.7%) and high molecular weight (35,284 g/mol) of reclaimed rubber could be achieved at 80 °C with a filling rate of 85%. Moreover, the obtained recycled rubber compound with SBR show a similar vulcanization characteristics to pure SBR. Our selective decomposition of waste rubber strategy opens up a new way for upgrading WR in shoe industry.

Degradable polymeric nanomaterials with a high solid content and multiple morphologies by polymerization-induced self-assembly.

The preparation of degradable polymeric nanomaterials with a high solid content and multiple morphologies is highly desirable but still challenging. Here, the RAFT dispersion polymerization of styrene and 5,6-benzo-2-methylene-1,3-dioxepane was demonstrated to achieve various morphologies, including spheres, vesicles, worms, and large compound vesicles, with a high solid content through polymerization-induced self-assembly, which opens up a new avenue for the preparation of degradable polymeric nanomaterials.

Endowing Acceptable Mechanical Properties of Segregated Conductive Polymer Composites with Enhanced Filler-Matrix Interfacial Interactions by Incorporating High Specific Surface Area Nanosized Carbon Black.

Tuning the high properties of segregated conductive polymer materials (CPCs) by incorporating nanoscale carbon fillers has drawn increasing attention in the industry and academy fields, although weak interfacial interaction of matrix-filler is a daunting challenge for high-loading CPCs. Herein, we present a facile and efficient strategy for preparing the segregated conducting ultra-high molecular weight polyethylene (UHMWPE)-based composites with acceptable mechanical properties. The interfacial interactions, mechanical properties, electrical properties and electromagnetic interference (EMI) shielding effectiveness (SE) of the UHMWPE/conducting carbon black (CCB) composites were investigated. The morphological and Raman mapping results showed that UHMWPE/high specific surface area CCB (h-CCB) composites demonstrate an obviously interfacial transition layer and strongly interfacial adhesion, as compared to UHMWPE/low specific surface area CCB (l-CCB) composites. Consequently, the high-loading UHMWPE/h-CCB composite (beyond 10 wt% CCB dosage) exhibits higher strength and elongation at break than the UHMWPE/l-CCB composite. Moreover, due to the formation of a densely stacked h-CCB network under the enhanced filler-matrix interfacial interactions, UHMWPE/h-CCB composite possesses a higher EMI SE than those of UHMWPE/l-CCB composites. The electrical conductivity and EMI SE value of the UHMWPE/h-CCB composite increase sharply with the increasing content of h-CCB. The EMI SE of UHMWPE/h-CCB composite with 10 wt% h-CCB is 22.3 dB at X-band, as four times that of the UHMWPE/l-CCB composite with same l-CCB dosage (5.6 dB). This work will help to manufacture a low-cost and high-performance EMI shielding material for modern electronic systems.

Construction of TiO2-Eggshell for Efficient Degradation of Tetracycline Hydrochloride: Sunlight Induced In-Situ Formation of Carbonate Radical.

Photocatalytic degradation of an antibiotic by utilizing inexhaustible solar energy represents an ideal solution for tackling global environment issues. The target generation of active oxidative species is highly desirable for the photocatalytic pollutants degradation. Herein, aiming at the molecular structure of tetracycline hydrochloride (TC), we construct sunlight-activated high-efficient catalysts of TiO2-eggshell (TE). The composite ingeniously utilizes the photoactive function of TiO2 and the composition of eggshell, which can produce oxidative ·CO3- species that are especially active for the degradation of aromatic compounds containing phenol or aniline structures. Through the synergistic oxidation of the··CO3- with the traditional holes (h+), superoxide radicals (·O2-) and hydroxyl radicals (·OH) involved in the photocatalytic process, the optimal TE photocatalyst degrades 92.0% TC in 30 min under solar light, which is higher than TiO2 and eggshell. The photocatalytic degradation pathway of TC over TE has been proposed. The response surface methodology is processed by varying four independent parameters (TC concentration, pH, catalyst dosage and reaction time) on a Box-Behnken design (BBD) to optimize the experimental conditions. It is anticipated that the present work can facilitate the development of novel photocatalysts for selective oxidation based on ·CO3-.

Adsorption-desorption behavior of methylene blue onto aged polyethylene microplastics in aqueous environments.

In this study, polyethylene microplastics were artificially photoaged by xenon light. Experiments were then performed with methylene blue (MB) dye to compare the changes in the structure, properties, and adsorption-desorption behaviors of the aged and virgin polyethylene microplastics. The results showed that the aged polyethylene microplastics were hydrophilic with oxygen-containing functional groups, which enhanced the adsorption capacity of polyethylene for MB from 0.63 mg·g-1 to 8.12 mg·g-1. The adsorption isotherms changed from the Henry model (virgin polyethylene microplastics) to the Langmuir model (aged polyethylene microplastics), indicating that the partitioning function was gradually replaced by a single-layer covering during the adsorption process. In addition, 7% and 17.8% of the MB loaded onto the aged polyethylene microplastics was desorbed into water and a simulated intestinal fluid, respectively. These findings reveal that aged polyethylene microplastics can accumulate MB, thus posing potential risks to aqueous environments and biological tissues.

Efficient Removal of Organic Contaminants from Aqueous Solution by Highly Compressible Reusable Three-Dimensional Printing Sponges.

Adsorption is considered to be one of the most effective and economically viable technologies for removing contaminants from the environment. However, the disadvantages of its high-cost complicated process and difficulty in efficient recycling limit its practical application. Herein, a thermoplastic elastomer-polyvinyl alcohol composite (LAY-FOMM 60) sponge three-dimensional structure (3D printing sponge) was fabricated by the fused filament fabrication combined with water erosion technique. The size and shape of the resultant sponge were tailored, and the batch of adsorption/desorption experiments of Rhodamine B (RhB) onto the sponge was performed. The results show that the adsorption of RhB on the 3D printing sponge was mainly via physical adsorption, and pseudo-second-order and Langmuir models exhibited good correlation with the adsorption kinetic and isotherm data, respectively. Thermodynamic parameters suggest that the adsorption is an endothermic and spontaneous process. It is worth to note that the adsorption/desorption efficiency can be raised by compression. This results in high efficiency and low cost for adsorption/desorption process and benefit for regeneration of the adsorbent. The adsorption capacity was maintained over 85% of the initial capacity after being used for five cycles. The approach provides a simple strategy for manufacturing customizable porous adsorbent materials that meet various water treatment requirements.

Boosting total oxidation of propane over CeO2@Co3O4 nanofiber catalysts prepared by multifluidic coaxial electrospinning with continuous grain boundary and fast lattice oxygen mobility.

A one-dimensional (1D) core-shell of Co-Ce oxide has been prepared by multifluidic coaxial electrospinning method and evaluated for the total oxidation of propane (C3H8). Activity and morphological characterizations show that the CeO2@Co3O4 nanofiber catalyst, of which the core is CeO2 and the shell is Co3O4, exhibits excellent oxidation activity. The exposed Co3O4 grown on the outside of the fibers can rapidly react with C3H8 while CeO2 with high oxygen storage capacity in the inside is conductive to the enhanced oxidation rate. Besides, the continuous grain boundary provides a fast mass transfer channel for lattice oxygen, and rich oxygen vacancies favor the mobility of active oxygen species. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) confirms that the CeO2@Co3O4 catalyst have a faster rate of C3H8 adsorption and better oxidation activity with respect to the counterpart using a single-needle electrospinning method. Moreover, the CeO2@Co3O4 catalyst displays excellent thermal stability, and strong resistance against 5 vol% H2O and 5 vol% CO2 at both 300 and 400 °C. Our strategy can give some new insights into morphological engineering to promote active oxygen mobility via the construction of one-dimensional core-shell of metal oxides for catalytic oxidation of VOCs.

In Situ Growth of Ca2+-Based Metal-Organic Framework on CaSiO3/ABS/TPU 3D Skeleton for Methylene Blue Removal.

The work reports a novel strategy for combining polymers and metal-organic frameworks (MOFs) into composites for adsorption applications. Calcium silicate (CaSiO3) was introduced into acrylonitrile butadiene styrene/thermoplastic polyurethane (ABS/TPU) alloy, and the CaSiO3/ABS/TPU skeleton was fabricated by 3D printing technology. The Ca-MOF was directly loaded on the surface of acetone-etched 3D skeleton by in-situ growth method. The obtained 3D skeleton was characterized and the performance of methylene blue (MB) adsorption was determined. It is clear that Ca-MOF is successfully loaded on the surface of 3D skeleton due to the presence of CaSiO3. The MB adsorption ratios of the solutions with initial concentrations of 50, 100 and 200 mg/L at the equilibrium time (5 h) are 88%, 88% and 80%, respectively, revealing good MB adsorption performance of the 3D skeleton. The MB adsorption ratio remains 70% at six runs of adsorption-desorption experiment, indicating the excellent recovering property of the skeleton. The results show that the prepared CaSiO3/ABS/TPU 3D skeleton is a candidate adsorbent for printing and dyeing effluent treatment.

A ZnO@ABS/TPU/CaSiO3 3D skeleton and its adsorption/photocatalysis properties for dye contaminant removal.

Both adsorption and photocatalysis are considered to be effective methods for removing organic contaminants from dye wastewater. In this study, the construction of 3D skeletons based on the nanoparticles ZnO and ABS/TPU/calcium silicate (CaSiO3) (shortened as ATC) were fabricated via fused deposition molding (FDM) technology. Characterization by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) depicted that ZnO nanospheres had been successfully grown on the 3D skeleton surface with an enlarged specific surface area. As the results of the RhB adsorption and photocatalytic degradation experiments showed, the removal ratio of RhB onto the ZnO-ATC skeleton was as high as 97.94% and the synergistic effect of adsorption and photocatalysis greatly shortened the RhB degradation time under ultraviolet light irradiation. The nanocomposites synthesized in this study showed a significant removal ability for organic pollutants, and could effectively overcome the limitation of the secondary removal of photocatalysts.

Simultaneously enhanced mechanical properties and flame retardancy of UHMWPE with polydopamine-coated expandable graphite.

The potential prospect of expandable graphite (EG) in the development of polymer composites is severely limited by required large additions and poor interface compatibility with the polymer. Inspired by mussels, polydopamine (PDA) can be used as an effective interface modifier for EG to prepare ultra high molecular weight polyethylene (UHMWPE) composites with superior mechanical properties and high flame retardancy. The surface of expandable graphite (EG) was coated with a thin adhesive PDA film through self-polymerization of dopamine. The modified expandable graphite (EG@PDA) was combined with APP to prepare UHMWPE flame retardant composites. Compared with UHMWPE/APP/EG (with 20 wt% APP/EG), UHMWPE/APP/EG@PDA (with 20 wt% APP/EG@PDA) gives a decrement by 16.7% in limiting oxygen index, 29.7% in the peak of the heat release rate, 20.4% in total heat release and 49.3% in total smoke release, with an increment by 37% in tensile strength and 67.9% in elongation at break, respectively. It is suggested that the presence of PDA as an interface modifier can greatly improve the interfacial compatibility between EG and UHMWPE. Moreover, it can lead to forming more char residue and reducing the release of smoke particulates during combustion of the composites.

Largely enhanced thermal conductivity and thermal stability of ultra high molecular weight polyethylene composites via BN/CNT synergy.

In recent years, thermally conductive polymer-based composites have garnered significant attention due to their light weight and easy formation process. In this work, the thermal conductivity of ultra high molecular weight polyethylene (UPE) composites was improved through construction of a hybrid filler network of boron nitride sheets (BNs) and carbon nanotubes (CNTs) in the matrix via hot compression. The morphology, UPE aggregate structure, thermal conductivity, heat dissipation capacity and thermal stability of the UPE composites were investigated. The thermal conduction mechanism of the UPE composites was explored through simulations with Agari's semi-empirical formula. The results showed that the thermal conductivity of the UPE composite with 40 wt% BNs and 7 wt% CNTs was 2.38 W m-1 K-1, which was 495% higher than that of pure UPE, showing a synergistic effect between BNs and CNTs. The simulations with Agari's semi-empirical simulation suggested that increasing the CNT content contributed to synergistically assist BNs to form a better continuous and effective hybrid filler thermal network, thereby reducing phonon scattering and thermal resistance between BNs. In addition, UPE composites doped with BNs and CNTs presented better heat dissipation capacity and higher thermal stability as compared to that of pure UPE.

S-Doped Sb2O3 Nanocrystal: an Efficient Visible-Light Catalyst for Organic Degradation.

The S-doped Sb2O3 nanocrystals were successfully synthesized using SbCl3 and thioacetamide (TAA) as precursors via a facile one-step hydrothermal method. The effects of pH of the precursor reaction solution on the product composition and property were determined. The results indicated that the doping amount of S could be tuned by adjusting the pH of the precursor solution. Furthermore, the S entered into the interstitial site of Sb2O3 crystals as S2-, which broadened the absorption wavelength range of the Sb2O3 nanocrystal. The S-doped Sb2O3 exhibited an excellent visible-light-driven photocatalytic activity in the decomposition of methyl orange and 4-phenylazophenol. Last, a possible photocatalytic mechanism of the S-doped Sb2O3 under visible light irradiation was proposed.

No effect of caloric restriction or exercise on radiation repair capacity.

INTRODUCTION: Maintenance of normal weight and higher levels of physical activity are associated with a reduced risk of several types of cancer. Because genomic instability is regarded as a hallmark of cancer development, one proposed mechanism is improvement of DNA repair function. We investigated links between dietary weight loss, exercise, and strand break rejoining in an ancillary study to a randomized-controlled trial. METHODS: Overweight/obese postmenopausal women (n = 439) were randomized to the following: a) reduced calorie weight loss diet ("diet," n = 118), b) moderate- to vigorous-intensity aerobic exercise ("exercise," n = 117), c) a combination ("diet + exercise," n = 117), or d) control (n = 87). The reduced calorie diet had a 10% weight loss goal. The exercise intervention consisted of 45 min of moderate to vigorous aerobic activity 5 d·wk for 12 months. DNA repair capacity was measured in a subset of 226 women at baseline and 12 months from cryopreserved peripheral mononuclear cells using the comet assay. Anthropometric and body composition measures were performed at baseline and 12 months. RESULTS: DNA repair capacity did not change significantly with any of the 12-month interventions compared with control; there were also no significant changes when stratified by changes in body composition or aerobic fitness (V˙O2max). At baseline, DNA repair capacity was positively associated with weight, body mass index, and fat mass (r = 0.20, P = 0.003; r = 0.19, P = 0.004; r = 0.13, P = 0.04, respectively) and inversely with lean body mass (r = -0.14, P = 0.04). CONCLUSION: In conclusion, DNA repair capacity in cryopreserved PBMCs (Comet Assay) did not change with dietary weight loss or exercise interventions in postmenopausal women within a period of 12 months. Other assays that capture different facets of DNA repair function may be needed.

The effects of separate and combined dietary weight loss and exercise on fasting ghrelin concentrations in overweight and obese women: a randomized controlled trial.

OBJECTIVE: Compensatory metabolic changes that accompany weight loss, for example, increased ghrelin, contribute to weight regain and difficulty in long-term weight loss maintenance; however, the separate effects of long-term caloric restriction and exercise on total circulating ghrelin in humans are unknown. DESIGN: A 12-month randomized controlled trial comparing: i) dietary weight loss with a 10% weight loss goal ('diet'; n = 118); ii) moderate-to-vigorous intensity aerobic exercise for 45 min/day, 5 days/week ('exercise'; n = 117); iii) dietary weight loss and exercise ('diet + exercise'; n = 117); or iv) no-lifestyle-change control (n = 87). PARTICIPANTS: 439 overweight or obese postmenopausal women (50-75 y). MEASUREMENTS: Fasting total serum ghrelin was measured by radioimmunoassay at baseline and 12 months. Fasting serum leptin, adiponectin and insulin were also measured. RESULTS: Fasting total ghrelin significantly increased in the diet + exercise arm (+7·4%, P = 0·008) but not in either the diet (+6·5%, P = 0·07) or exercise (+1·0%, P = 0·53) arms compared with control. Greater weight loss was associated with increased ghrelin concentrations, regardless of intervention. Neither baseline ghrelin nor body composition modified the intervention effects on changes in total ghrelin. The 12-month change in total ghrelin was inversely associated with changes in leptin, insulin and insulin resistance, and positively associated with change in adiponectin. CONCLUSIONS: Greater weight loss, achieved through a reduced calorie diet or exercise, is associated with increased total ghrelin concentrations in overweight or obese postmenopausal women.

Plasma choline metabolites and colorectal cancer risk in the Women's Health Initiative Observational Study.

Few studies have examined associations between plasma choline metabolites and risk of colorectal cancer. Therefore, we investigated associations between plasma biomarkers of choline metabolism [choline, betaine, dimethylglycine, and trimethylamine N-oxide (TMAO)] and colorectal cancer risk among postmenopausal women in a case-control study nested within the Women's Health Initiative Observational Study. We selected 835 matched case-control pairs, and cases were further stratified by tumor site (proximal, distal, or rectal) and stage (local/regional or metastatic). Colorectal cancer was assessed by self-report and confirmed by medical records over the mean of 5.2 years of follow-up. Baseline plasma choline metabolites were measured by LC/MS-MS. In multivariable-adjusted conditional logistic regression models, plasma choline tended to be positively associated with rectal cancer risk [OR (95% confidence interval, CI)(highest vs. lowest quartile) = 2.44 (0.93-6.40); P trend = 0.08], whereas plasma betaine was inversely associated with colorectal cancer overall [0.68 (0.47-0.99); P trend = 0.01] and with local/regional tumors [0.64 (0.42-0.99); P trend = 0.009]. Notably, the plasma betaine:choline ratio was inversely associated with colorectal cancer overall [0.56 (0.39-0.82); P trend = 0.004] as well as with proximal [0.66 (0.41-1.06); P trend = 0.049], rectal [0.27 (0.10-0.78); P trend = 0.02], and local/regional [0.50 (0.33-0.76); P trend = 0.001] tumors. Finally, plasma TMAO, an oxidative derivative of choline produced by intestinal bacteria, was positively associated with rectal cancer [3.38 (1.25-9.16); P trend = 0.02] and with overall colorectal cancer risk among women with lower (vs. higher) plasma vitamin B12 levels (P interaction = 0.003). Collectively, these data suggest that alterations in choline metabolism, which may arise early in disease development, may be associated with higher risk of colorectal cancer. The positive association between plasma TMAO and colorectal cancer risk is consistent with an involvement of the gut microbiome in colorectal cancer pathogenesis.

Aspirin and serum estrogens in postmenopausal women: a randomized controlled clinical trial.

Epidemiologic studies suggest a reduced risk of breast cancer among women who use aspirin. A plausible mechanism is through aspirin's effect on estrogens, possibly mediated through interference with estrogen synthesis via reduction in inflammation, which is increased in adipose tissues, including breast. In a randomized placebo-controlled trial, we evaluated the effects of six-month administration of 325 mg/day aspirin on serum estrogens (estradiol, estrone, free estradiol, and bioavailable estradiol) and sex hormone-binding globulin (SHBG) in 144 healthy postmenopausal women. Eligible participants, recruited 2005-2007, were not taking nonsteroidal anti-inflammatory medication, including aspirin >2 times/week or menopausal hormone therapy, and had a Breast Imaging-Reporting and Data System (BI-RADS) mammographic density classification of 2, 3, or 4. The intervention effects (intent-to-treat) were evaluated by differences in the geometric mean outcome changes at six months between aspirin and placebo groups using generalized estimating equations (GEE). Participants were a mean 59.4 (SD, 5.4) years of age, with a mean body mass index (BMI) of 26.4 (SD, 5.4) kg/m(2). Between baseline and six months, none of the serum estrogens or SHBG changed substantially and there were no differences between groups. Stratifying by BMI did not change results. In conclusion, a single daily administration of 325 mg of aspirin for six months had no effect on serum estrogens or SHBG in postmenopausal women. Larger doses or longer duration of aspirin administration may be needed to affect circulating estrogens. Alternately, if aspirin influences breast cancer risk in postmenopausal women, it may do so through direct breast tissue effects, or through pathways other than estrogens.