•Highly controlled hydrothermal liquefaction of DDGS in a unique stop-flow reactor.•Investigation of effect of heterogeneous catalyst ZrO2 and reactor steel.•Bio-oil characterization in terms of ...yield, char, ash, composition and heating value.•Low oxygen biofuel with high heating value in single step reaction.
Hydrothermal liquefaction of biomass is a promising technology for production of biofuels. In this work, the catalytic effect of a nanocrystalline zirconia catalyst on hydrothermal liquefaction of dried distiller’s grains with solubles (DDGS) was investigated using a stop-flow reactor system. Additionally, the catalytic effects originating from the reactor wall were also studied by means of an inert gold liner to isolate the reaction from the X22 reactor alloy. DDGS was converted into a crude bio-oil at a fixed reaction temperature (350°C), pressure (250bar) and reaction time (15min). The oil was characterized in terms of yield, char content, ash content, elemental composition, chemical composition and heating value. Neither the ZrO2 catalyst nor the reactor wall was found to have any significant effects on the yields and properties of the produced bio-oil. Consequently, ZrO2 appears to be a poor catalyst for hydrothermal liquefaction of biomass. The X22 alloy is found to be highly suitable for construction of hydrothermal liquefaction reactors.
It is predicted that Japan and European Union will soon experience appreciable decreases in their populations due to persistently low total fertility rates (TFR) below replacement level (2.1 child ...per woman). In the United States, where TFR has also declined, there are ethnic differences. Caucasians have rates below replacement, while TFRs among African-Americans and Hispanics are higher. We review possible links between TFR and trends in a range of male reproductive problems, including testicular cancer, disorders of sex development, cryptorchidism, hypospadias, low testosterone levels, poor semen quality, childlessness, changed sex ratio, and increasing demand for assisted reproductive techniques. We present evidence that several adult male reproductive problems arise in utero and are signs of testicular dysgenesis syndrome (TDS). Although TDS might result from genetic mutations, recent evidence suggests that it most often is related to environmental exposures of the fetal testis. However, environmental factors can also affect the adult endocrine system. Based on our review of genetic and environmental factors, we conclude that environmental exposures arising from modern lifestyle, rather than genetics, are the most important factors in the observed trends. These environmental factors might act either directly or via epigenetic mechanisms. In the latter case, the effects of exposures might have an impact for several generations post-exposure. In conclusion, there is an urgent need to prioritize research in reproductive physiology and pathophysiology, particularly in highly industrialized countries facing decreasing populations. We highlight a number of topics that need attention by researchers in human physiology, pathophysiology, environmental health sciences, and demography.
Abstract
Context
The lack of sensitive and robust analytical methods has hindered the reliable quantification of estrogen metabolites in subjects with low concentrations.
Objective
To establish ...sex-specific reference ranges for estrone (E1) and estradiol (E2) throughout life and to evaluate sex-differences using the state-of-the-art liquid chromatography tandem mass spectrometry (LC-MS/MS) method for quantification of E1, E2, and estriol (E3).
Design
LC-MS/MS method development and construction of estrogen reference ranges.
Settings
Population-based cross-sectional cohorts from the greater Copenhagen and Aarhus areas.
Participants
Healthy participants aged 3 months to 61 years (n = 1838).
Results
An isotope diluted LC-MS/MS method was developed and validated for measurements of serum E1, E2, and E3. Limits of detections (LODs) were 3 pmol/L (E1), 4 pmol/L (E2), and 12 pmol/L (E3), respectively. This sensitive method made it possible to differentiate between male and female concentration levels of E1 and E2 in children. In girls, E2 levels ranged from <LOD to 100 pmol/L during mini-puberty, whereas it was ≤20 pmol/L during childhood. E1 and E2 increased with age and pubertal breast stage and varied during the menstrual cycle; E1 was lower than E2 in girls and premenopausal women, and higher than E2 in postmenopausal women. In boys, E1 and E2 increased with age and pubertal stage, whereas little changes with age were observed in men. High E3 concentrations were confirmed in pregnant women.
Conclusion
Reference ranges of simultaneous quantification of E1 and E2 by this novel specific and highly sensitive LC-MS/MS method provide an invaluable tool in clinical practice and in future research studies.
Hydrothermal liquefaction is a promising technique for the production of bio-oil. The process produces an oil phase, a gas phase, a solid residue, and an aqueous phase. Gas chromatography coupled ...with mass spectrometry is used to analyze the complex aqueous phase. Especially small organic acids and nitrogen-containing compounds are of interest. The efficient derivatization reagent methyl chloroformate was used to make analysis of the complex aqueous phase from hydrothermal liquefaction of dried distillers grains with solubles possible. A circumscribed central composite design was used to optimize the responses of both derivatized and nonderivatized analytes, which included small organic acids, pyrazines, phenol, and cyclic ketones. Response surface methodology was used to visualize significant factors and identify optimized derivatization conditions (volumes of methyl chloroformate, NaOH solution, methanol, and pyridine). Twenty-nine analytes of small organic acids, pyrazines, phenol, and cyclic ketones were quantified. An additional three analytes were pseudoquantified with use of standards with similar mass spectra. Calibration curves with high correlation coefficients were obtained, in most cases R ² > 0.991. Method validation was evaluated with repeatability, and spike recoveries of all 29 analytes were obtained. The 32 analytes were quantified in samples from the commissioning of a continuous flow reactor and in samples from recirculation experiments involving the aqueous phase. The results indicated when the steady-state condition of the flow reactor was obtained and the effects of recirculation. The validated method will be especially useful for investigations of the effect of small organic acids on the hydrothermal liquefaction process. Graphical Abstract Schematic illustration of hydrothermal liquefaction of biomass.
During the past two decades human exposure to bisphenol A (BPA) and phthalates such as di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), butylbenzyl phthalate (BBzP) and di-(2-ethyl-hexyl) ...phthalate (DEHP) has received substantial interest due to widespread population exposures and potential endocrine disrupting effects. Therefore, these chemicals have gradually been restricted and phased out through legislation. However, humans are still exposed to a wide range of other less studied phthalates, phthalate substitutes and BPA analogues as well as other polychlorinated and phenolic substances.
In this study, we investigated human exposure to these chemicals over the past decade. Three hundred urine samples collected in 2009, 2013 and 2017 (100 samples each year) from young Danish men of the general population, participating in a large on-going cross-sectional study, were selected for the present time trend study. The urinary concentration of metabolites of 15 phthalates, di-2-ethylhexyl terephthalate (DEHTP) and di-iso-nonyl-cyclohexane-1,2-dicarboxylate (DINCH), seven bisphenols including BPA, bisphenol S (BPS) and bisphenol F (BPF), as well as triclosan, triclocarban, benzophenone-3, three chlorophenols and two phenylphenols were analyzed by two new sensitive LC-MS/MS methods developed and validated for the present study.
A significant decrease in urinary concentrations over time was observed for the majority of the chemicals. Median concentrations of BPA and the metabolites of DiBP, DnBP, BBzP and DEHP were more than halved from 2009 to 2017. Similar decreases were observed for triclosan and the chloro- and phenylphenols. In contrast, metabolites of the two phthalate substitutes DEHTP and DINCH increased more than 20 and 2 times, respectively. The potential BPA substitutes; BPS and BPF also increased, but only slightly. Despite these new exposure patterns, the exposure to the old well-known chemicals, such as DiBP, DnBP, BBzP, DEHP and BPA was still higher in 2017 compared to the exposure level of the new substitutes such as DEHTP, DINCH, BPS and BPF.
A significant decrease in internal exposure to most of the common phthalates and BPA over the past decade was observed, reflecting market changes and regulatory measures implemented in EU. Despite increasing exposures to some of the known phthalate substitutes and BPA analogues, the total amount of each measured chemical group (original and substitute analytes combined) was lower in the more recently collected samples. This indicates only partial direct substitution or substitution by chemicals not covered in this approach, or a general decline in the exposure to these chemical/product groups over the last decade.
A severe decline in child births has occurred over the past half century, which will lead to considerable population declines, particularly in industrialized regions. A crucial question is whether ...this decline can be explained by economic and behavioural factors alone, as suggested by demographic reports, or to what degree biological factors are also involved. Here, we discuss data suggesting that human reproductive health is deteriorating in industrialized regions. Widespread infertility and the need for assisted reproduction due to poor semen quality and/or oocyte failure are now major health issues. Other indicators of declining reproductive health include a worldwide increasing incidence in testicular cancer among young men and alterations in twinning frequency. There is also evidence of a parallel decline in rates of legal abortions, revealing a deterioration in total conception rates. Subtle alterations in fertility rates were already visible around 1900, and most industrialized regions now have rates below levels required to sustain their populations. We hypothesize that these reproductive health problems are partially linked to increasing human exposures to chemicals originating directly or indirectly from fossil fuels. If the current infertility epidemic is indeed linked to such exposures, decisive regulatory action underpinned by unconventional, interdisciplinary research collaborations will be needed to reverse the trends.
Recent publications showing unexpectedly early breast development in American girls created debate worldwide. However, secular trend analyses are often limited by poor data comparability among ...studies performed by different researchers in different time periods and populations. Here we present new European data systematically collected from the same region and by 1 research group at the beginning and end of the recent 15-year period.
Girls (N = 2095) aged 5.6 to 20.0 years were studied in 1991-1993 (1991 cohort; n = 1100) and 2006-2008 (2006 cohort; n = 995). All girls were evaluated by palpation of glandular breast, measurement of height and weight, and blood sampling (for estradiol, luteinizing hormone, and follicle-stimulating hormone). Age distribution at entering pubertal breast stages 2 through 5, pubic hair stages 2 through 5, and menarche was estimated for the 2 cohorts.
Onset of puberty, defined as mean estimated age at attainment of glandular breast tissue (Tanner breast stage 2+), occurred significantly earlier in the 2006 cohort (estimated mean age: 9.86 years) when compared with the 1991 cohort (estimated mean age: 10.88 years). The difference remained significant after adjustment for BMI. Estimated ages at menarche were 13.42 and 13.13 years in the 1991 and 2006 cohorts, respectively. Serum follicle-stimulating hormone and luteinizing hormone did not differ between the 2 cohorts at any age interval, whereas significantly lower estradiol levels were found in 8- to 10-year-old girls from the 2006 cohort compared with similarly aged girls from the 1991 cohort.
We found significantly earlier breast development among girls born more recently. Alterations in reproductive hormones and BMI did not explain these marked changes, which suggests that other factors yet to be identified may be involved.
The purpose of this paper is to give a comprehensive description of the construction and commissioning of a continuous reactor system for hydrothermal liquefaction of biomass. The basis is a newly ...established facility at Aarhus University. It is capable of handling viscous biomass slurries and features a novel induction-based heating method that facilitates well-defined reaction environments. Carbon balance closure is obtained as all product fractions are recovered and positively quantified. The paper includes a residence time distribution measurement and a 24 h proof-of-concept experiment conducted at 350 °C, 250 bar, and 15 min reaction time. It is based on the biomass dried distillers grains with solubles, a waste product of the bioethanol industry. The experiment seeks to determine the steady-state characteristics of the continuous reactor system for use in future experimental studies. It was found that steady state occurs within 6 h. Furthermore, data sampling windows of 2.1 h were found to mask the intrinsic variations of the system while still exposing trends. At steady state, the oil mass yield was found to be 38.9 ± 3.2% and the higher heating value was 35.3 ± 0.28 MJ kg–1.
Introduction:
Increasing evidence suggests that endocrine-disrupting chemicals (EDCs) contribute to male reproductive diseases and disorders.
Purpose:
To estimate the incidence/prevalence of selected ...male reproductive disorders/diseases and associated economic costs that can be reasonably attributed to specific EDC exposures in the European Union (EU).
Methods:
An expert panel evaluated evidence for probability of causation using the Intergovernmental Panel on Climate Change weight-of-evidence characterization. Exposure-response relationships and reference levels were evaluated, and biomarker data were organized from carefully identified studies from the peer-reviewed literature to represent European exposure and approximate burden of disease as it occurred in 2010. The cost-of-illness estimation utilized multiple peer-reviewed sources.
Results:
The expert panel identified low epidemiological and strong toxicological evidence for male infertility attributable to phthalate exposure, with a 40–69% probability of causing 618 000 additional assisted reproductive technology procedures, costing €4.71 billion annually. Low epidemiological and strong toxicological evidence was also identified for cryptorchidism due to prenatal polybrominated diphenyl ether exposure, resulting in a 40–69% probability that 4615 cases result, at a cost of €130 million (sensitivity analysis, €117–130 million). A much more modest (0–19%) probability of causation in testicular cancer by polybrominated diphenyl ethers was identified due to very low epidemiological and weak toxicological evidence, with 6830 potential cases annually and costs of €848 million annually (sensitivity analysis, €313–848 million). The panel assigned 40–69% probability of lower T concentrations in 55- to 64-year-old men due to phthalate exposure, with 24 800 associated deaths annually and lost economic productivity of €7.96 billion.
Conclusions:
EDCs may contribute substantially to male reproductive disorders and diseases, with nearly €15 billion annual associated costs in the EU. These estimates represent only a few EDCs for which there were sufficient epidemiological studies and those with the highest probability of causation. These public health costs should be considered as the EU contemplates regulatory action on EDCs.
Abuse of anabolic androgenic steroids (AAS) is highly prevalent among male recreational athletes. The objective of this study was to investigate the impact of AAS abuse on reproductive hormone levels ...and symptoms suggestive of hypogonadism in current and former AAS abusers.
This study had a cross-sectional case-control design and involved 37 current AAS abusers, 33 former AAS abusers (mean (95%CI) elapsed duration since AAS cessation: 2.5 (1.7; 3.7) years) and 30 healthy control participants. All participants were aged 18-50 years and were involved in recreational strength training. Reproductive hormones (FSH, LH, testosterone, inhibin B and anti-Müllerian hormone (AMH)) were measured using morning blood samples. Symptoms of hypogonadism (depressive symptoms, fatigue, decreased libido and erectile dysfunction) were recorded systematically.
Former AAS abusers exhibited significantly lower median (25th -75th percentiles) total and free testosterone levels than control participants (total testosterone: 14.4 (11.9-17.7) nmol/l vs. 18.8 (16.6-22.0) nmol/l) (P < 0.01). Overall, 27.2% (13.3; 45.5) of former AAS abusers exhibited plasma total testosterone levels below the lower reference limit (12.1 nmol/l) whereas no control participants exhibited testosterone below this limit (P < 0.01). Gonadotropins were significantly suppressed, and inhibin B and AMH were significantly decreased in current AAS abusers compared with former AAS abusers and control participants (P < 0.01). The group of former AAS abusers had higher proportions of participants with depressive symptoms ((24.2%) (11.1; 42.2)), erectile dysfunction ((27.3%) (13.3; 45.6)) and decreased libido ((40.1%) (23.2; 57.0)) than the other two groups (trend analyses: P < 0.05).
Former AAS abusers exhibited significantly lower plasma testosterone levels and higher frequencies of symptoms suggestive of hypogonadism than healthy control participants years after AAS cessation. Current AAS abusers exhibited severely decreased AMH and inhibin B indicative of impaired spermatogenesis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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