Hydrogen technologies can play an important role in decarbonising our energy system in a variety of ways across the energy value chain. It is therefore critical to identify the strategic roles as ...well as the conditions under which hydrogen energy systems become attractive for the energy transition. In this paper, the authors present a techno-economic review of hydrogen energy systems including power-to-power, power-to-gas, hydrogen refuelling and stationary fuel cells. We focus on their optimal operation as flexible assets and we identify three actions that can foster their uptake beyond technological progress. First, we recommend optimal electricity supply with dedicated control strategies considering that electricity dominates the levelised cost of hydrogen production via electrolysis. Secondly, hydrogen can enable the further integration of traditionally independent sectors, namely electricity, heat and transport while contributing to decarbonise all. This position can also be advantageous for investors who sell heat and fuels as energy efficient products. Lastly, we examine a whole range of revenues from different products and applications which can be combined (i.e. benefit stacking) to match capital and operational expenditures. We discuss these roles in depth and we conclude that policy makers together with technology developers should elaborate smart strategies to reduce cost by scaling production, stimulate standardisation (e.g., similar to the PV industry) as well as develop new market structures and regulatory frameworks which allow hydrogen technologies to deliver multiple low carbon applications and products.
•The role of PtG, power-to-power, hydrogen refuelling and fuel cell are evaluated.•The value of various products and services offered by hydrogen systems is given.•Recommendations are given for minimising the levelised cost of electrolysis.•We review electronics and control techniques for various hydrogen energy systems.•Key strategies such as further system linkage and benefit stacking are discussed.
Breast cancer is one of the common tumors occurring in woman and despite treatment, the prognostic is poor. Genistein, a soy isoflavone, has been reported to have chemopreventive\chemotherapeutic ...potential in multiple tumor types. Here, we investigated the genistein antiproliferative effect in MCF-7 breast cancer, underlying the molecular mechanisms involved in this effect. MCF-7 cancer and CCD1059sK fibroblast cells were treated with estradiol (10 nM) or genistein (0.01–100 μM) for 24, 48, and 72 h and the cell proliferation was investigated by MTT; membrane cell permeability was evaluated by LDH and PI incorporation; apoptosis was investigated by externalization of phosphatidylserine by FACS; and presence of autophagy was detected by LC3A/B immunostaining. The expression of apoptotic proteins and antioxidant enzymes was evaluated by qPCR. The results demonstrate that genistein (100 μM) for 72 h of treatment selectively reduced MCF-7 cell proliferation independent of estrogen receptor activation, while no cytotoxicity was observed in fibroblast cells. Further experiments showed that genistein induced phosphatidylserine externalization and LC3A/B immunopositivity in MCF-7 cells, indicating apoptosis and autophagy cell death. Genistein increased in three times proapoptotic BAX/Bcl-2 ratio and promoted a parallel downregulation of 20 times of antiapoptotic survivin. In addition, genistein promoted a decrease of 5.5, 9.3, and 3.6 times of MnSOD, CuZnSOD, and TrxR mRNA expression, respectively, while the GPx expression was increased by 6.5 times. These results suggest that the antitumor effect of genistein involved the modulation of antioxidant enzyme and apoptotic signaling expression, which resulted in apoptosis and progression of autophagy.
The continuous trend for a narrowing margin between feed cost and milk prices across dairy farms in the United States highlights the need to improve and maintain feed efficiency. Yeast culture ...products are alternative supplements that have been evaluated in terms of milk performance and feed efficiency; however, less is known about their potential effects on altering rumen microbial populations and consequently rumen fermentation. Therefore, the objective of this study was to evaluate the effect of yeast culture supplementation on lactation performance, rumen fermentation profile, and abundance of major species of ruminal bacteria in lactating dairy cows. Forty mid-lactation Holstein dairy cows (121 ± 43 days in milk; mean ± standard deviation; 32 multiparous and 8 primiparous) were used in a randomized complete block design with a 7-d adaptation period followed by a 60-d treatment period. Cows were blocked by parity, days in milk, and previous lactation milk yield and assigned to a basal total mixed ration (TMR; 1.6 Mcal/kg of dry matter, 14.6% crude protein, 21.5% starch, and 38.4% neutral detergent fiber) plus 114 g/d of ground corn (CON; n = 20) or basal TMR plus 100 g/d of ground corn and 14 g/d of yeast culture (YC; n = 20; Culture Classic HD, Cellerate Yeast Solutions, Phibro Animal Health Corp.). Treatments were top-dressed over the TMR once a day. Cows were individually fed 1 × /d throughout the trial. Blood and rumen fluid samples were collected in a subset of cows (n = 10/treatment) at 0, 30, and 60 d of the treatment period. Rumen fluid sampled via esophageal tubing was analyzed for ammonia-N, volatile fatty acids (VFA), and ruminal bacteria populations via quantitative PCR amplification of 16S ribosomal DNA genes. Milk yield was not affected by treatment effects. Energy balance was lower in YC cows than CON, which was partially explain by the trend for lower dry matter intake as % body weight in YC cows than CON. Cows fed YC had greater overall ruminal pH and greater total VFA (mM) at 60 d of treatment period. There was a contrasting greater molar proportion of isovalerate and lower acetate proportion in YC-fed cows compared with CON cows. Although the ruminal abundance of specific fiber-digesting bacteria, including Eubacterium ruminantium and Ruminococcus flavefaciens, was increased in YC cows, others such as Fibrobacter succinogenes were decreased. The abundance of amylolytic bacteria such as Ruminobacter amylophilus and Succinimonas amylolytica were decreased in YC cows than CON. Our results indicate that the yeast culture supplementation seems to promote some specific fiber-digesting bacteria while decreasing amylolytic bacteria, which might have partially promoted more neutral rumen pH, greater total VFA, and isovalerate.
Puberty is regulated by epigenetic mechanisms and is highly sensitive to metabolic and nutritional cues. However, the epigenetic pathways mediating the effects of nutrition and obesity on pubertal ...timing are unknown. Here, we identify Sirtuin 1 (SIRT1), a fuel-sensing deacetylase, as a molecule that restrains female puberty via epigenetic repression of the puberty-activating gene, Kiss1. SIRT1 is expressed in hypothalamic Kiss1 neurons and suppresses Kiss1 expression. SIRT1 interacts with the Polycomb silencing complex to decrease Kiss1 promoter activity. As puberty approaches, SIRT1 is evicted from the Kiss1 promoter facilitating a repressive-to-permissive switch in chromatin landscape. Early-onset overnutrition accelerates these changes, enhances Kiss1 expression and advances puberty. In contrast, undernutrition raises SIRT1 levels, protracts Kiss1 repression and delays puberty. This delay is mimicked by central pharmacological activation of SIRT1 or SIRT1 overexpression, achieved via transgenesis or virogenetic targeting to the ARC. Our results identify SIRT1-mediated inhibition of Kiss1 as key epigenetic mechanism by which nutritional cues and obesity influence mammalian puberty.
Lurbinectedin is a novel and potent selective inhibitor of active transcription of protein-coding genes, triggering apoptosis of cancerous cells. It has been approved for the treatment of patients ...with metastatic small-cell lung cancer with disease progression on or after platinum-based chemotherapy. Studies exploring the disposition and metabolism of lurbinectedin were performed in vitro and in vivo (by intravenous administration of lurbinectedin). Low blood cell partitioning for lurbinectedin in rats, nonhuman primates (NHP), and humans was determined as 23.4%, 29.8%, and 9.8%, respectively. Protein binding was very high (>95%) in total plasma (rat, NHP, and human), albumin, and
-1-acid glycoprotein (both human). In vitro, lurbinectedin underwent intense liver microsome-mediated metabolism-in 10 minutes, 80% of the compound is metabolized in human-with CYP3A4 being the isoform involved in that metabolism. Results also showed NHPs being the nonclinical species which, metabolically, most closely resembles humans. Mass balance studies performed in rats (both genders), NHPs (male only), and patients (both genders) demonstrated that the principal route of excretion of
C-lurbinectedin-related radioactivity was through the feces (88.7% ± 10.1% in patients), with only a minor fraction recovered from the urine (5.6% ± 2.0% in patients). In plasma samples, the majority of lurbinectedin-related radioactivity was attributed to unchanged compound (95% ± 3.1% and 70.2% ± 10.9% in NHPs and humans, respectively). Plasma metabolic profiling demonstrated the major (% compared with unchanged compound) circulating metabolites were
-Desmethyl-lurbinectedin (0.4% ± 0.2% and 10.4% ± 2.2% in NHPs and patients, respectively) and 1',3'-Desmethylene-lurbinectedin (0.9% ± 0.7% and 14.3% ± 10.4% in NHP and patients, respectively). SIGNIFICANCE STATEMENT: Lurbinectedin is a novel and potent selective inhibitor of active transcription of protein-coding genes, triggering apoptosis of cancerous cells, and was recently approved for the treatment of patients with metastatic small-cell lung cancer with disease progression on or after platinum-based chemotherapy. The present study provides a complete set of information on the pharmacokinetics, biotransformation, and elimination of
C-lurbinectedin and its metabolites, following a single intravenous administration to nonclinical species (rats and nonhuman primates) and patients.
The objective of this study was to evaluate the effect of different forms of trace minerals (TM) and the use of different starch levels in dairy heifer diets on rumen fermentation and digestibility. ...Eight rumen cannulated dairy heifers (15.4 ± 0.8 mo of age and 438.31 ± 18.08 kg of body weight) were subjected to a split-plot, 4 × 4 Latin square design with 19-d periods: 15d of adaptation and 4d of sampling. The whole-plot factor was type of TM; organic as proteinates (OTM) or inorganic sulfates (ITM), and the subplot was starch level (3.54, 12.95, 22.25, and 31.73%). Total collection of feces and urine was completed on d 15 to 19 to determine digestibility and TM excretion. Rumen contents were sampled on d 18 to 19 at 0, 1, 2, 4, 8, 12, 16, 20, and 22 h after feeding to measure pH and volatile fatty acid (VFA) concentrations. Plasma samples were collected to evaluate TM concentrations and enzymatic activity for ceruloplasmin, glutathione peroxidase, and superoxide dismutase. Starch level affected pH, individual VFA concentrations, and nutrient excretion. Trace mineral intake was lower for OTM compared with ITM. No effect of TM form on dry matter digestibility was detected, but as level of starch increased, diet dry matter digestibility increased. Rumen pH was lower for diets with OTM, which is consistent with higher total VFA production and butyrate proportion observed for heifers fed OTM diets. These variables may be explained by the higher bioavailability of OTM and faster utilization and fermentation by rumen microorganisms. Heifers that consumed ITM had higher moisture in feces and higher urine excretion, which increased total manure production. Total excretion of TM was not different by treatment. Blood plasma mineral concentration was not different between treatments except for Mn, which was higher for OTM. Enzymatic activity was not affected by treatments. Mineral intake was reduced and blood mineral levels were not different, suggesting enhanced absorption of OTM compared with ITM. In conclusion, based on rumen pH, VFA production, and plasma TM concentration, OTM may be more ruminally bioavailable and absorbed to a greater extent than ITM. Also, TM form affected fecal moisture and urine excretion, suggesting that ITM may stimulate water intake.
•A conceptual analysis of operation modes in energy storage plants is presented.•Key Performance Indicators to select operation modes are provided.•The approach has been applied to a laboratory ...hybrid power plant.•The methodology provides guidance for the operation of hybrid power plants.
This paper is concerned with Operating Modes in hybrid renewable energy-based power plants with hydrogen as the intermediate energy storage medium. Six operation modes are defined according to plant topology and the possibility of operating electrolyzer and fuel cell at steady-power or partial load. A methodology for the evaluation of plant performance is presented throughout this paper. The approach includes a set of simulations over a fully validated model, which are run in order to compare the proposed operation modes in various weather conditions. Conclusions are drawn from the simulation stage using a set of Key Performance Indicators defined in this paper. This analysis yields the conclusion that certain modes are more appropriate from technical and practical standpoints when they are implemented in a real plant. From the results of the simulation assessment, selected operating modes are applied to an experimental hydrogen-based pilot plant to illustrate and validate the performance of the proposed operation modes. Experimental results confirmed the simulation study, pointing out the advantages and disadvantages of each operation mode in terms of performance and equipment durability.
This paper describes the design and validation of a mathematical model for a solar Fresnel collector. The function of the model is to simulate the optical and thermal dynamics of a Fresnel system for ...heating water. The model is validated using real data gathered from a cooling plant with double effect absorption chiller located in the School of Engineering University of Seville, Spain (Experimental cooling plant is also described in the paper). Comparison of calculated and plant measured data shows that the error is lower than 3% in the optical model and within 7% in the thermal model.
The model uses a new approach to include a solar tracking mirror mechanism in one axis. This tracking has been designed to maximise the reception of available solar radiation by the absorption pipe. The thermal model used is based around classical models for solar receivers and it is validated with real operating data gathered from a supervisor system.
The Fresnel model has been designed with sufficient flexibility to consider different geometries and thermal parameters, and may be used to simulate the performance of a proposed Fresnel collector system at any location.
Sorghum silage has been shown to be a good alternative to corn silage for dairy cows; however, studies regarding heifers are insufficiently explored. Therefore, the objective of this study was to ...evaluate effects of changing forage to concentrate ratio (FOR:CON) in diets based on sorghum silage on N digestibility, rumen fermentation, N balance, C excretion, and microbial N yield in limit-fed dairy heifers. A split-plot 4×4 Latin square design with 19-d periods (15 d of adaptation and 4 d of sampling) was conducted with 8 rumen cannulated dairy heifers (age 13.7±0.6mo and weight 364.8±17.6kg). Heifers were fed sorghum silage–based diets with 4 FOR:CON (85:15, 75:25, 65:35, and 55:45) balanced for similar metabolizable energy intake per unit of body weight and crude protein concentration. Diets were fed to allow 900 to 1,000g/d body weight gain and were fed once daily. Total collection of feces and urine was completed on d 15 to 19 to determine N, C, urea N, allantoin, uric acid, and creatinine excretion. Rumen contents were sampled on d 19 at 0, 1.5, 3, 4.5, 6, 9, 13, 17, 21, and 23h after feeding to measure pH, volatile fatty acid (VFA), ammonia-N, and free AA concentrations. The pH decreased linearly while ammonia-N and free AA levels increased linearly with decreasing FOR:CON of diets. Although mean total VFA did not differ among treatment diets, molar proportions of VFA did. Acetate proportion decreased while propionate and butyrate increased with decreasing FOR:CON. Intake of N and urea N excretion decreased with decreasing forage proportion in diets while total N excretion, apparent N digestibility, and N retention were not different. Intake of C and excretion in feces (g/d) decreased linearly with decreasing FOR:CON in diets. Creatinine, allantoin, and uric acid excretion were not affected by FOR:CON; however, microbial N yield tended to increase linearly with greater concentrate in diets. Heifers limit fed diets based on sorghum silage demonstrated the effect of available ammonia-N and readily fermentable carbohydrates with subsequent effects on nutrient utilization when different FOR:CON were applied. Based on the presented results, FOR:CON 65:35 had the most suitable balance of available ammonia-N and readily fermentable carbohydrates for the most optimal results.
Deep habits and travel resilience after COVID-19 Boto-García, David; Baños-Pino, José F
Tourism economics : the business and finance of tourism and recreation,
03/2023, Letnik:
29, Številka:
2
Journal Article
Recenzirano
Odprti dostop
This research examines how deep travel habits in the form of habit formation and reduced substitutability between tourism travel and other leisure goods impact travel resilience after COVID-19. Using ...microdata for almost 3000 tourists in Andalusia (Spain), we relate post-pandemic outbreak tourism participation to pre-pandemic travelling intensity and whether taking a vacation is considered a priority good. In doing so, we control for standard sociodemographic characteristics and province fixed effects. Our results clearly show that the probability of continuing travelling during the summer of 2020 is positively associated with pre-pandemic travel intensity and tourism being considered a priority leisure activity. Travel resilience is found to be strongly associated with income, education level and the tenure of a second residence.
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