Energy Requirements Research Articles

A Mediterranean dietary pattern intervention does not improve cardiometabolic risk but does improve quality of life and body composition in an Aotearoa New Zealand population at increased cardiometabolic risk: A randomised controlled trial.

To test if a New Zealand food-based Mediterranean diet (NZMedDiet) with behavioural intervention improves cardiometabolic health and wellbeing. A randomised controlled trial comparing 12 weeks of the NZMedDiet to usual diet in participants with increased cardiometabolic risk (metabolic syndrome severity score [MetSSS] > 0.35). The intervention group was provided with food and recipes to meet 75% of their energy requirements, supported by a behavioural intervention to improve adherence. The primary outcome measure was (MetSSS) after 12 weeks. Two hundred individuals with mean (SD) age 49.9 (10.9) years of which 62% women were enrolled with their household/whānau. After 12 weeks, the mean (SD) MetSSS was 1.0 (0.7) in the control (n = 98) and 0.8 (0.5) in the intervention (n = 102) group; estimated difference (95% confidence interval [CI]) of -0.05 (-0.16 to 0.06), p = 0.35. The Mediterranean diet score (PyrMDS) was greater in the intervention group 1.6 (1.1-2.1), p < 0.001, consistent with a change to a more Mediterranean dietary pattern. Weight reduced in the NZMedDiet group compared with control (-1.9 kg [-2.0 to -0.34]), p = 0.006 and wellbeing, assessed by the SF-36 quality of life questionnaire, and improved across all domains. For example, the physical component summary score difference (95% CI) was 4.0 (2.4-5.7), p < 0.001, and the mental component summary score difference was 3.0 (0.7-5.2), p = 0.01. In participants with increased cardiometabolic risk, food provision with a Mediterranean dietary pattern and a behavioural intervention did not improve metabolic risk scores but was associated with reduced weight and improved quality of life.

Nutrient intake of young South African adults from the baseline of the African-PREDICT cohort study.

This study aimed to describe and compare the nutrient intake of young adults in the African Prospective Study on the Early Detection and Identification of Cardiovascular Disease and Hypertension (African-PREDICT) study according to ethnicity and socioeconomic status (SES). Cross-sectional analysis of baseline nutrient intakes in the African-PREDICT study. North West Province, South Africa. Black and white adults (n=1153), aged 20-30 years, were classified into three SES groups. Dietary data were collected using three multiple-pass 24-hour dietary recalls. Among all participants, over 70% failed to meet the Estimated Energy Requirements and the Estimated Average Requirements (EAR) for 17 of the 19 reported micronutrients. Across SES groups, more than 50% of participants consistently did not meet the EAR for calcium, magnesium, folate, pantothenic acid, and biotin, as well as vitamins A, C, D, and E. Participants' distribution by nutrient pattern tertiles showed high adherence to two patterns: one rich in animal protein and saturated fat, and the other in magnesium, potassium, calcium, phosphorus, and fiber. This was seen only in white participants and high SES. Black participants and low SES showed higher adherence to a plant protein, B-vitamins, zinc, and iron nutrient pattern. The dietary intake of young adults in this study was restricted, with none of the groups meeting nutrient requirements for essential nutrients. Further research is needed to establish a direct link between nutrient patterns and the early detection and identification of cardiovascular diseases and hypertension.

Seawater alkalization via an energy-efficient electrochemical process for CO2 capture

Electrochemical pH-swing strategies offer a promising avenue for cost-effective and energy-efficient carbon dioxide (CO2) capture, surpassing the traditional thermally activated processes and humidity-sensitive techniques. The concept of elevating seawater's alkalinity for scalable CO2 capture without introducing additional chemical as reactant is particularly intriguing due to its minimal environmental impact. However, current commercial plants like chlor-alkali process or water electrolysis demand high thermodynamic voltages of 2.2 V and 1.23 V, respectively, for the production of sodium hydroxide (NaOH) from seawater. These high voltages are attributed to the asymmetric electrochemical reactions, where two completely different reactions take place at the anode and cathode. Here, we developed a symmetric electrochemical system for seawater alkalization based on a highly reversible and identical reaction taking place at the anode and cathode. We utilize hydrogen evolution reaction at the cathode, where the generated hydrogen is looped to the anode for hydrogen oxidation reaction. Theoretical calculations indicate an impressively low energy requirement ranging from 0.07 to 0.53 kWh/kg NaOH for established pH differences of 1.7 to 13.4. Experimentally, we achieved the alkalization with an energy consumption of 0.63 kWh/kg NaOH, which is only 38% of the theoretical energy requirements of the chlor-alkali process (1.64 kWh/kg NaOH). Further tests demonstrated the system's potential of enduring high current densities (~20 mA/cm2) and operating stability over an extended period (>110 h), showing its potential for future applications. Notably, the CO2 adsorption tests performed with alkalized seawater exhibited remarkably improved CO2 capture dictated by the production of hydroxide compared to the pristine seawater.

Signaling Pathways Concerning Mitochondrial Dysfunction: Implications in Neurodegeneration and Possible Molecular Targets.

Mitochondrion is an important organelle present in our cells responsible for meeting energy requirements. All higher organisms rely on efficient mitochondrial bioenergetic machinery to sustain life. No other respiratory process can produce as much power as generated by mitochondria in the form of ATPs. This review is written in order to get an insight into the magnificent working of mitochondrion and its implications in cellular homeostasis, bioenergetics, redox, calcium signaling, and cell death. However, if this machinery gets faulty, it may lead to several disease states. Mitochondrial dysfunctioning is of growing concern today as it is seen in the pathogenesis of several diseases which includes neurodegenerative disorders, cardiovascular disorders, diabetes mellitus, skeletal muscle defects, liver diseases, and so on. To cover all these aspects is beyond the scope of this article; hence, our study is restricted to neurodegenerative disorders only. Moreover, faulty functioning of this organelle can be one of the causes of early ageing in individuals. This review emphasizes mutations in the mitochondrial DNA, defects in oxidative phosphorylation, generation of ROS, and apoptosis. Researchers have looked into new approaches that might be able to control mitochondrial failure and show a lot of promise as treatments.

Microscale chemiresistive hydrogen sensors: Current status and recent developments

Hydrogen is known for its efficient combustion, abundant natural availability, and environmentally friendly characteristics. It is recognized as a promising energy source for the future and is already utilized in various industries, including petrochemicals, electronics, food processing, aerospace, and new energy vehicles. However, challenges arise in the storage and use of hydrogen owing to its tendency to leak, its potential for explosion within a specific concentration range of 4%–75%, and itslow ignition energy requirements. Consequently, there is a demand for hydrogen sensors capable of quickly and accurately detecting low levels of hydrogen leaks. Microelectromechanical systems-based chemiresistive hydrogen sensors offer advantages such as low cost, compact size, low energy consumption, and superior sensing performance, making them a major focus of recent research. This article provides a comprehensive overview and comparison of the sensing principles of various hydrogen sensors, including chemiresistive sensors, electrochemical sensors, thermocatalytic sensors, acoustic sensors, and mechanical sensors. Micro-chemiresistive hydrogen sensors exhibit high sensitivity, low cost, and ease of integration, making them highly promising for practical applications. In response to the challenges encountered in practical applications of chemiresistive hydrogen sensors, such as high operating temperatures and high power consumption, this review explores emerging trends in chemiresistive hydrogen sensor technology from the perspectives of novel materials and activation methods. Finally, it discusses the applications and potential further developments of chemiresistive hydrogen sensors.

Trans-10 shifted ruminal biohydrogenation and its implications for ruminant milk and meat fat content and quality

Feeding high-grain diets is a common practice in intensive ruminant production systems to meet animal energy requirements and maximize feed efficiency. One of the consequences of these diets is trans (t)10 shifted ruminal biohydrogenation, which includes increased formation of t10-18:1 and t10,cis (c)12-conjugated linoleic acid (t10,c12-CLA) at the expense of t11-18:1 and c9,t11-CLA. In dairy cows, the t10 shift has been associated with milk fat depression. In beef cattle, the t10 shift has not been associated with negative effects on animal performance or marbling fat deposition, however, it may negatively impact meat fat eating quality by decreasing its cis monounsaturated fatty acid to saturated fatty acid ratio. Finally, the t10 shift increases t10-18:1 accumulation in ruminant-derived foods (dairy, beef and lamb) which at high enough levels may compromise the nutritional quality of these foods. The present review will cover our current understanding of the rumen microbes involved in the t10 shift and its implications for milk fat synthesis and beef fat quality.

Effect of Age at First Calving on the Reproduction Parameters, Metabolic Profile, and Fatty Acid Composition of Polish Holstein Friesian (PHF) and Crossbreds PHF × Swedish Red (SRB) Cattle

Background: The high dairy production of Polish Holstein Friesian (PHF) cows determines high energy requirements in the early stages of lactation. Unfortunately, it is very often difficult to meet this demand through feedstuffs; therefore, homeostasis may be disturbed and metabolic diseases may occur, causing a majority of cows’ health problems. Breeders are, therefore, looking for alternatives to the PHF breed using crossbreeding. Methods: This experiment involved 30 PHF cows and 30 PHF × Swedish Red (SRB) crossbred hybrid cows, divided into two age groups, &lt;2 years and &gt;2 years, at first calving. Milk and blood samples were collected at 35 ± 5 days postpartum for analysis. Data on reproductive performance were also analyzed. Results: This study revealed lower milk production for the crossbreds hybrid (27.44 kg compared to 32.08 kg), with a higher basic composition content than PHF cows (fat: 3.97% compared to 3.83%, protein: 3.53% compared to 3.27%). The heifers of the crossbreds hybrid reached sexual maturity earlier but did not affect the lower age at first calving. Dividing the cows into age categories provided a more detailed perspective of the impact of genotypic differences on reproductive and metabolic profiles in PHF and PHF × SRB cattle. The findings highlight the importance of considering age-specific effects when assessing the performance and health of dairy cattle with diverse genotypes. Conclusions: The choice between PHF and PHF × SRB should depend on the specific goals and priorities of the cattle farming operation. Factors such as overall milk yield requirements, market demands, reproductive management strategies, and health considerations should be carefully evaluated to determine the most suitable breed for a given farming context.

Innovative Strategies for Combining Solar and Wind Energy with Green Hydrogen Systems

The integration of wind and solar energy with green hydrogen technologies represents an innovative approach toward achieving sustainable energy solutions. This review examines state-of-the-art strategies for synthesizing renewable energy sources, aimed at improving the efficiency of hydrogen (H2) generation, storage, and utilization. The complementary characteristics of solar and wind energy, where solar power typically peaks during daylight hours while wind energy becomes more accessible at night or during overcast conditions, facilitate more reliable and stable hydrogen production. Quantitatively, hybrid systems can realize a reduction in the levelized cost of hydrogen (LCOH) ranging from EUR 3.5 to EUR 8.9 per kilogram, thereby maximizing the use of renewable resources but also minimizing the overall H2 production and infrastructure costs. Furthermore, advancements such as enhanced electrolysis technologies, with overall efficiencies rising from 6% in 2008 to over 20% in the near future, illustrate significant progress in this domain. The review also addresses operational challenges, including intermittency and scalability, and introduces system topologies that enhance both efficiency and performance. However, it is essential to consider these challenges carefully, because they can significantly impact the overall effectiveness of hydrogen production systems. By providing a comprehensive assessment of these hybrid systems (which are gaining traction), this study highlights their potential to address the increasing global energy demands. However, it also aims to support the transition toward a carbon-neutral future. This potential is significant, because it aligns with both environmental goals and energy requirements. Although challenges remain, the promise of these systems is evident.

Towards value-added chemicals: Technical and environmental life cycle assessment evaluation of different glycerol valorisation pathways

Biodiesel is acknowledged as the most appropriate biofuel to decarbonise the transport sector and combat climate change. The ever-increasing biodiesel production via transesterification results in large amount of glycerol (e.g., 10 kg of glycerol for every 100 kg of biodiesel). Converting glycerol into value-added goods is perceived to be a viable way to lower the high cost of producing biodiesel and expand its market share. The current study examines the technical and environmental aspects of bio-hydrogen, bio-syngas, acrolein, propylene glycol, epichlorohydrin, bio-methanol and bio-ethanol synthesis. CHEMCAD process simulation software was used to perform the modelling and simulation aspects considering a glycerol flowrate of 100 kg/h. The environmental study is based on primary and secondary data and is carried out using the Life Cycle Assessment methodology and the LCA for Experts software, using ReCiPe as the impact assessment method. The technical evaluation points towards glycerol conversion to propylene glycol and bio-methanol production as the best approaches given the relatively low energy requirements, increased purity (>97 wt%) and steadily growing product market. Bio-methanol exhibits the best environmental performance among all examined scenarios, providing the lowest impact in eight out of eleven categories studied while placing second in terms of FETP impact. Glycerol conversion towards propylene glycol seems as the second-best conversion route as it generates the lowest score in regards to GWP impact (0.31 kg CO2 eq./ kgproduct). Ultimately, the most effective methods for valorizing glycerol and improving the production of biodiesel by lowering the expenses related to its manufacturing are glycerol reforming toward bio-methanol and propylene glycol.

Nutrition support for patients with renal dysfunction in the intensive care unit: A narrative review.

Providing optimal nutrition support in the intensive care unit (ICU) is a challenging and dynamic process. Energy, protein, fluid, electrolyte, and micronutrient requirements all can be altered in patients with acute, chronic, and acute-on-chronic kidney disease. Given that renal dysfunction occurs in up to one-half of ICU patients, it is imperative that nutrition support providers understand how renal dysfunction, its metabolic consequences, and its treatments, including renal replacement therapy (RRT), affect patients' nutrition needs. Data on nutrient requirements in critically ill patients with renal dysfunction are sparse. This article provides an overview of renal dysfunction in the ICU and identifies and addresses the unique nutrition challenges present among these patients, including those receiving RRT, as supported by the available literature and guidelines.

A Bio-Inspired Magnetic Soft Robotic Fish for Efficient Solar-Energy Driven Water Purification.

Solar-driven water evaporation is a promising solution for global water scarcity but is still facing challenges due to its substantial energy requirements. Here, a magnetic soft robotic bionic fish is developed by combining magnetic nanoparticles (Fe3O4), poly(N-isopropylacrylamide), and carboxymethyl chitosan. This bionic fish can release liquid water through hydrophilic/hydrophobic phase transition and dramatically reduce energy consumption. The introduced Fe3O4 nanoparticles endow the bionic fish with magnetic actuation capability, allowing for remote operation and recovery. Additionally, the magnetic actuation process accelerates the water absorption rate of the bionic fish as confirmed by the finite element simulations. The results demonstrate that bionic fish can effectively remove not only organic molecular dyes dissolved in water but also harmful microbes and insoluble microparticles from natural lakes. Moreover, the bionic fish maintains a good purification efficiency even after five recycling cycles. Furthermore, the bionic fish possesses other functions, such as salt purification and salt rejection. Finally, the mechanism of water purification is explained in conjunction with molecular dynamics calculations. This work provides a new approach for efficient solar-energy water purification by phase transition behavior in soft robotics.

Association of time to start of enteral nutrition and outcome in cats with hepatic lipidosis.

Enteral nutrition (EN) is essential for management of hepatic lipidosis (HL) in cats. To determine if time to start of EN and other clinicopathologic variables are associated with outcome in cats with HL. Forty-eight cats with HL. Retrospective study. Information retrieved from medical records and client communications included clinicopathologic findings, time to start of EN, initial % of resting energy requirements provided, type of feeding tube, duration of hospitalization, and 3-month survival. Variables were compared between surviving and nonsurviving cats and between cats fed ≤12 hours and >12 hours after hospital admission. Multivariable statistical testing was performed to further investigate variables of interest. Seventeen of 25 (68%) cats fed ≤12 hours and 13 of 23 (57%) of cats fed >12 hours after hospital admission survived (P = .55). Only increasing age (odds ratio [OR], 1.313; 95% confidence interval [CI], 1.032-1.671; P = .03) and the presence of ascites (OR, 6.415; 95% CI, 1.354-30.395; P = .02) were associated with death in multivariable analysis. Hospitalization duration (median, interquartile range [IQR]) was shorter in cats fed >12 hours (2.8 days; IQR, 2.1-3.8 days) as compared with cats fed ≤12 hours (4.8 days; IQR, 3.6-6.2 days) after hospital admission (P < .001). An initial stabilization period before EN introduction does not decrease survival or increase duration of hospitalization in cats with HL.

MnO2 nanowires modified reduced graphene oxide thick film cathode for aqueous zinc-ion prismatic battery

Aqueous zinc-ion batteries are an excellent alternative to lithium-ion batteries that can meet the energy requirements while also being safe and eco-friendly. However, developing a suitable cathode material with good energy density and high-rate capability is challenging. In this study, we developed an aqueous zinc-ion battery with a high surface area MnO2 nanowires modified reduced graphene oxide nanocomposite screen printed interdigitated array electrodes and a distinctive aqueous electrolyte comprising 1 M each of ZnSO4 and Na2SO4, 0.1 M MnSO4, and 0.8 mM sodium dodecyl sulfate. The charge-discharge curves reveal that the cathode material exhibits a high reversible storage capacity of 164 mAh g−1 at a current density of 50 mA g−1. The battery retained 99.59% of its Coulombic efficiency after 300 cycles when cycled at a high current rate of 300 mA g−1. The prismatic battery realized exhibited a calculated energy density of 505.5 Wh kg−1 which is higher than previously reported works. On account of the large energy density and high rate capability coupled with non-toxic components, low cost and facile fabrication method, the Zn||MnO2/rGO battery shows good promise for energy storage application.

Nutrition support in children discharged from the pediatric intensive care unit: A bi-national prospective cohort study (ePICUre).

The role of nutrition in the recovery of critically ill children has not been investigated and current nutrition provision in the post-pediatric intensive care unit (PICU) period is unknown. The primary objective of this study was to describe ward nutrition support in children following PICU discharge. Children up to 18 years admitted to one of nine PICUs over a 2-week period with a length of stay >48 h were enrolled. Data were collected on the first full ward day following PICU discharge and on Days 7, 14, 21, and 28 following PICU admission. Data points included oral intake, enteral (EN) and parenteral nutrition (PN) support, and oral and EN energy and protein provision. Among the 108 children, on the first full ward day 75/108 (69%) children received EN, 54/108 (50%) oral intake, and 8/108 (7%) PN. Of those receiving oral nutrition only on the first full ward day (25/108; 23%), 9/25 (36%) received <50% of their estimated energy and protein requirements. Of those provided EN only, and where nutrition targets were known, on the first full ward day 8/46 (17%) and 7/46 (15%) met <75% of their estimated energy and protein requirements, respectively. On Day 28, this increased to 4/12 (33%) and 5/12 (42%). In this study of ward-based nutrition support, key findings included consistent use of EN and PN up to at least 28 days following PICU admission, and a high proportion of children receiving EN or oral intake only not meeting their estimated energy and protein requirements.

Uranium removal from contaminated groundwater using goethite-loaded composite microporous membrane

In this study, we have coupled adsorption and membrane separation for the removal of uranium from contaminated groundwater in environmentally relevant conditions at low energy requirements. This study mainly focuses on elucidating uranium, U(VI), adsorption mechanisms using surface complexation modeling approach in a novel goethite-loaded composite microfiltration membrane (GLM). This experiment involved immobilizing goethite nanorods in a microporous (0.22 μm pore size) poly (vinylidene fluoride) (PVDF) membrane. The effect of varying goethite loading and hydraulic residence time on U(VI) removal was investigated at field-relevant pH (i.e. pH 8.5). U(VI) adsorption (i.e. 4.95 μg·mg−1) was optimum at a goethite loading 1.20 mg·cm−2. The effect of varying hydraulic residence time had no impact on U(VI) removal which was also confirmed via performing batch adsorption kinetic experiments. GLM membrane loaded at 1.2 mg·cm−2 could treat 275 L of U(VI) contaminated water having 200 μg of U L−1 below WHO drinking water limit (i.e. 30 μg of U L−1) with 1 m2 of membrane surface area with a adsorption capacity of 6.12 μg·mg−1. Varying the pH of aqueous solution, containing U(VI) from pH 4.0 to pH 10.0, showed a significant impact on uranium uptake ranging from 0.7 μg·mg−1 to 2.63 μg·mg−1 by the composite membrane. The adsorption mechanism of uranium onto goethite was explained via the formation of bidentate surface complexes using the Surface Complexation Model (SCM). The results of batch pH edge experiments and SCM have been compared with pH experiments performed using GLM. The results of SCM predicted the batch pH edge experiment within a RMSE of 0.055. The trend of U(VI) removal in membrane experiments was observed to be similar to that of batch pH edge experiments and was well predicted SCM model. Our results showed that the novel goethite-loaded membrane has the potential for the effective removal of uranium with a lower specific energy consumption.

Development of a Reliable Assay of Eco-friendly Fe3O4@Ag Nanocomposite-Based Giant Magnetoresistance Sensor

Abstract For the development of green magnetic-based immunoassay devices, the rapid and reliable assay method of eco-friendly magnetic labels with a lower energy requirement is vital. This work proposes a green-synthesized Fe3O4@Ag magnetic label assay system using GMR chips and a simple microcontroller-based data acquisition tool. Optical analysis shows the successful synthesis of Fe3O4@Ag with the assistance of Moringa oleifera (MO) extract as a reducing and stabilizing agent. Meanwhile, according to characterization, MO-assisted green-synthesized Fe3O4@Ag nanocomposites feature cubic inverse spinel structures and ferromagnetic characteristics that possess multi-domain structures. The sensor system generates an intense signal, varying from tens to hundreds of millivolts, allowing for its detection using a simple microcontroller system. The sensor exhibits a stable and reliable response to the increase in the concentration of Fe3O4@Ag nanocomposite, even though it is subjected to weak magnetic field induction. Furthermore, the introduction of Ag on the surface of Fe3O4 nanoparticles succeeded in optimizing the detection features, as evidenced by the lower limit of detection compared to detecting the bare Fe3O4. The GMR-based sensor, featuring a simple microcontroller structure and an eco-friendly Fe3O4@Ag nanocomposite as a magnetic label, exhibits significant potential as a rapid and reliable green biosensor that is power-efficient.

Interface Engineering Induced by Low Ru Doping in Ni/Co@NC Derived from Ni-ZIF-67 for Enhanced Electrocatalytic Overall Water Splitting.

Electrochemical water splitting is a promising approach for hydrogen evolution reactions (HER); however, the oxygen evolution reaction (OER) remains a major bottleneck due to its high energy requirements. High-performance electrocatalysts capable of facilitating HER, OER, and overall water splitting (OWS) are highly needed to improve OER kinetics. In this work, we synthesized a trimetallic heterostructure of Ru, Ni, and Co incorporated into N-doped carbon (denoted as Ru/Ni/Co@NC) by first synthesizing Ni/Co@NC from Ni-ZIF-67 polyhedrons via high-temperature carbonization, followed by Ru doping using the galvanic replacement method. Benefiting from increased active surface sites, modulated electronic structure, and enhanced interfacial synergistic effects, Ru/Ni/Co@NC exhibited exceptional electrocatalytic performance for both HER and OER processes. The optimized Ru/Ni/Co@NC catalyst, with a minimal Ru mass ratio of ∼2.07%, demonstrated significantly low overpotential values of 34 mV for HER and 174 mV for OER at a current density of 10 mA/cm2 with corresponding Tafel slope values of 33.42 and 34.39 mV/dec, respectively. Further, the optimized catalyst was loaded onto carbon paper and used as anode and cathode materials for alkaline water splitting. Interestingly, a low cell voltage of just 1.44 V was obtained. The enhanced electrolytic performance was further elaborated by density functional theory (DFT) calculations, which confirmed that Ru doping in Ni/Co introduced additional active sites for H*, enhancing adsorption/desorption abilities for HER (ΔGH* = -0.30 eV), lowering water dissociation barrier (ΔGb = 0.49 eV) and reducing the energy barrier for the rate-determining step of OER (O* → OOH*) to 1.62 eV in an alkaline environment. These findings reflect the significant potential of ZIF-67-based catalysts in energy conversion and storage applications.

Life cycle assessment in additive manufacturing of copper alloys—comparison between laser and electron beam

AbstractAdditive manufacturing is becoming increasingly important for industrial production. In this context, directed energy deposition processes are in demand to achieve high deposition rates. In addition to the well-known laser-based processes, the electron beam has also reached industrial market maturity. The wire electron beam additive manufacturing offers advantages in the processing of copper materials, for example. In the literature, the higher energy efficiency and the resulting improvement in the carbon footprint of the electron beam are highlighted. However, there is a lack of practical studies with measurement data to quantify the potential of the technology. In this work, a comparative life cycle assessment between wire electron beam additive manufacturing (DED-EB) and laser powder additive manufacturing (DED-LB) is carried out. This involves determining the resources for manufacturing, producing a test component using both processes, and measuring the entire energy consumption. The environmental impact is then estimated using the factors global warming potential (GWP100), photochemical ozone creation potential (POCP), acidification potential (AP), and eutrophication potential (EP). It can be seen that wire electron beam additive manufacturing is characterized by a significantly lower energy requirement. In addition, the use of wire ensures greater resource efficiency, which leads to overall better life cycle assessment results.

Cardiorenal ketone metabolism in healthy humans assessed by 11C-acetoacetate PET: effect of D-β-hydroxybutyrate, a meal, and age

The heart and kidney have a high energy requirement, but relatively little is known about their utilization of ketones as a potential energy source. We assessed the metabolism of the ketone tracer, carbon-11 acetoacetate (11C-AcAc), by the left and right ventricles of the heart and by the kidney using positron emission tomography (PET) in n = 10 healthy adults under four experimental conditions: a 4-h fast (fasted) ± a single 12 g oral dose of D-beta-hydroxybutyrate (D-BHB), and a single complete, liquid replacement meal (hereafter referred to as the “fed” condition) ± a single 12 g oral dose of D-BHB. Under these experimental conditions, the kinetics of 11C-AcAc metabolism fitted a two-compartment model in the heart and a three-compartment model in the kidney. Plasma ketones were about 10-fold higher with the oral dose of D-BHB. During the four conditions, tracer kinetics were broadly similar in the myocardium and kidney cortex. 11C-AcAc metabolism by the kidney pelvis was similar in three of the four study conditions but, later, peaked significantly higher than that in the cortex; the exception was that the tracer uptake was significantly lower in the fed condition without D-BHB. 11C-AcAc uptake was significantly inversely correlated with age in the kidney cortex, and its oxidative metabolism was significantly positively correlated with age in the left ventricle. D-BHB blunted the insulin, gastric inhibitory peptide, and C-peptide response to the meal. This PET methodology and these acute metabolic perturbations would be suitable for future studies assessing cardiorenal ketone metabolism in conditions in which heart and kidney functions are experimentally modified or compromised by disease.

Crystal structure of the 4-hydroxybutyryl-CoA synthetase (ADP-forming) from nitrosopumilus maritimus

The 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle from ammonia-oxidizing Thaumarchaeota is currently considered the most energy-efficient aerobic carbon fixation pathway. The Nitrosopumilus maritimus 4-hydroxybutyryl-CoA synthetase (ADP-forming; Nmar_0206) represents one of several enzymes from this cycle that exhibit increased efficiency over crenarchaeal counterparts. This enzyme reduces energy requirements on the cell, reflecting thaumarchaeal success in adapting to low-nutrient environments. Here we show the structure of Nmar_0206 from Nitrosopumilus maritimus SCM1, which reveals a highly conserved interdomain linker loop between the CoA-binding and ATP-grasp domains. Phylogenetic analysis suggests the widespread prevalence of this loop and highlights both its underrepresentation within the PDB and structural importance within the (ATP-forming) acyl-CoA synthetase (ACD) superfamily. This linker is shown to have a possible influence on conserved interface interactions between domains, thereby influencing homodimer stability. These results provide a structural basis for the energy efficiency of this key enzyme in the modified 3HP/4HB cycle of Thaumarchaeota.