Wet Mass Research Articles

Lead and Other Trace Element Levels in Brains of Croatian Large Terrestrial Carnivores: Influence of Biological and Ecological Factors.

Trace element pollution can adversely affect the brains of individuals and thus impact the entire population of apex predators, such as large European carnivores. We assessed exposure to prominent neurotoxicants As, Cd, Hg and Pb by measuring their brain stem levels in brown bears (n = 114), grey wolves (n = 8), Eurasian lynx (n = 3), and golden jackals (n = 2) sampled in 2015-2022 in Croatia. The highest of the non-essential elements was the Pb level in the bears' brains (median, Q1-Q3; 11.1, 7.13-24.1 μg/kg wet mass), with 4% of animals, all subadults, exceeding the established normal bovine levels (100 μg/kg wet mass). Species-specific differences were noted for Ca, Cd, Cu, Fe, Pb and Se brain levels. Female brown bears had higher As brain levels than males. Cubs and yearlings had lower brain Cd, but higher Zn, while subadults had higher Cu than adult bears. Hepatic As, Cd, Cu and Hg levels were shown to be a moderate proxy for estimating brain levels in bears (rS = 0.30-0.69). Multiple associations of As, Cd, Hg and Pb with essential elements pointed to a possible interaction and disturbance of brain Ca, Cu, Fe, Se and Zn homeostasis. Non-essential element levels in the brains of four studied species were lower than reported earlier for terrestrial meso-carnivores and humans. The age and sex of animals were highlighted as essential factors in interpreting brain element levels in ecotoxicological studies of large carnivores.

Can short-term data accurately model long-term environmental exposures? Investigating the multigenerational adaptation potential of Daphnia magna to environmental concentrations of organic ultraviolet filters

Organic ultraviolet filters (UVFs) are contaminants of concern, ubiquitously found in many aquatic environments due to their use in personal care products to protect against ultraviolet radiation. Research regarding the toxicity of UVFs such as avobenzone, octocrylene and oxybenzone indicate that these chemicals may pose a threat to invertebrate species; however, minimal long-term studies have been conducted to determine how these UVFs may affect continuously exposed populations. The present study modeled the effects of a 5-generation exposure of Daphnia magna to these UVFs at environmental concentrations. Avobenzone and octocrylene resulted in minor, transient decreases in reproduction and wet mass. Oxybenzone exposure resulted in > 40% mortality, 46% decreased reproduction, and 4-fold greater reproductive failure over the F0 and F1 generations; however, normal function was largely regained by the F2 generation. These results indicate that Daphnia are able to acclimate over long-term exposures to concentrations of 6.59 μg/L avobenzone, ∼0.6 μg/L octocrylene or 16.5 μg/L oxybenzone. This suggests that short-term studies indicating high toxicity may not accurately represent long-term outcomes in wild populations, adding additional complexity to risk assessment practices at a time when many regions are considering or implementing UVF bans in order to protect these most sensitive invertebrate species.

In Vitro Effectiveness Test of Sagoo Cortex Liquid Smoke to Inhibit the Growth of Ganoderma orbiforme (Fr.) Ryvarden

Ganoderma orbiforme is a pathogenic fungus that cause basal stem rot especially in oil palm, so it needs to be controlled. One of the alternative controls used is liquid smoke. This research aims to examine several concentrations of sagoo cortex liquid smoke to inhibit the growth of G. orbiforme in vitro. This research was conducted in October untill Desember 2021 at the Pathology, Entomology, Microbiology and Soil Science Laboratory, Faculty of Agriculture and Animal Science, Islamic State University Sultan Syarif Kasim Riau. Research was test of 6 concentrations of sagoo cortex liquid smoke (0, 1, 2, 3, 4, and 5%) with 4 replications. Liquid smoke had a total phenol ± 7.44%. Sagoo cortex liquid smoke with 1% concentration has already very effective to inhibit in the macroscopic, microscopic, growth rate, wet mass and dry mass

The functional significance of residual yolk in lizards.

Residual yolk is assumed to be an important source of energy and nutrients during early life in nonmammalian amniotes. Available data show that the mean size of residual yolk is far smaller in lizards than in turtles, snakes, crocodiles, and birds, raising a question of whether residual yolk is of functional significance in lizards. Here, we compared data from 26 lizard species with those from other nonmammalian amniotes to test the hypothesis that residual yolk is functionally less significant in species producing more fully developed offspring. In our sample, species mean offspring water contents ranged from 73% to 84% of body wet mass; species mean proportions of carcass dry mass, fat-body dry mass, and residual yolk dry mass to offspring dry mass ranged from 84% to 99%, 0% to 5.0%, and 0% to 14.4%, respectively. Lizards are, on average, more fully developed at hatching or birth than snakes, as revealed by the fact that the mean proportion of carcass dry mass to body dry mass and offspring water contents were both higher in lizards than in snakes. We conclude that the functional significance of residual yolk during early life is generally less evident in lizards. Even in the lizards where residual yolk is of potential functional significance, this portion of yolk contributes little, if any, to postembryonic growth. Future work could usefully collect data across a wider spectrum of reptile taxa to establish a precocial-altricial continuum and test the hypothesis that species with a smaller amount of residual yolk are closer to the precocial end of the continuum.

Heavy metal contamination in European conger (Conger conger, Linnaeus 1758) along the coastline of Morocco

BackgroundIn Morocco, fish is an important protein source especially, even not exclusively, for coastal communities and marketed fresh all along the coastline. One of the main targets of coastal artisanal fisheries is the European conger (Conger conger, Linnaeus 1758), a widely distributed benthic predatory species of a maximum weight of up to 50 kg. However, information on heavy metal contamination of conger is scarce. Therefore, concentrations of mercury, lead and cadmium were analysed in 108 European conger specimens from nine locations along the along the Atlantic and Mediterranean coasts of Morocco to describe the spatial distribution of heavy metal contamination.ResultsThe average heavy metal concentration in all conger samples under investigation was 246.90 ± 216.83 µg mercury/kg wet mass, 74.14 ± 87.02 µg lead/kg wet mass and 255.12 ± 287.15 µg cadmium/kg wet mass respectively. Mercury and cadmium showed a clear site-specific bioaccumulation in European conger but lead does not. Hence, the effect of fish length bias on contamination was corrected through a generalized linear model (GLM) prior to any spatial comparison.ConclusionsDifferent regional hotspots for the three analysed metals are identified and local sources are discussed. Mercury levels in big specimens of European conger exceeded the European threshold level for human consumption at some of the locations under investigation.

Development of Composition and Technology of Effervescent Tablets with Biologically Active Complex of Black Chokeberry (<i>Aronia melanocarpa</i> (Michx.) Elliott) Fruits

Introduction. Actual use of plant raw materials in the production of medicines is caused by a variety of bioactive substance complexes in their composition. These drugs have a wide range of therapeutic effects and in this regard, the properties and compositions of various plant materials are currently being actively studied. Aronia melanocarpa (chokeberry) has been the focus of scientific research for many years to identify various healing properties, and in 2015 its fresh and dried fruits are presented as a plant raw material in the State Pharmacopoeia of the Russian Federation, XIV edition. The variety of biologically active substance complexes of Aronia melanocarpa fruit allows its use in different fields (food and pharmaceutical industries). For this reason, the development of the composition and technology of effervescent tablets containing a complex of biologically active substances and possessing the following advantages: rapid release of active ingredients, high rate of BAS assimilation, usability and pleasant flavor are of interest.Aim. The aim of the present study is to develop the composition and technology of effervescent tablets with a biologically active complex from dried Аronia melanocarpa fruits.Materials and methods. Extracts enriched with anthocyanins were obtained from dried chokeberry fruits. As excipients in the technology of effervescent tablets, sodium carbonate, tartaric acid, lactose monohydrate, povidone (Plasdone™ K-29/32), polyethylene glycol 6000 and aspartame were used. Under laboratory conditions, granules (acidic and basic) were obtained by the method of punching wet masses, where extract (granulate 1) and ethyl alcohol 96 % (granulate 2) were used as a moisturizer. Numerical indicators of medicinal plant raw materials, technological properties of granulate and tableting mass, as well as quality indicators of effervescent tablets were determined according to the methods described in the State Pharmacopoeia of the Russian Federation, XIV edition.Results and discussion. Numerical indicators of dry fruits of Aronia melanocarpa (crushing of raw materials and the content of foreign impurities, total ash in plant raw materials and ash insoluble in hydrochloric acid, content of extractives) were determined, and the good quality of the raw materials used in the subsequent stages of drug development was confirmed. An extract enriched with anthocyanins has been developed. The composition and technology of effervescent tablets with separate granulation of acidic and basic components has been developed. Extract and ethyl alcohol 96 % were used as moisturizers, and aspartame was used to improve taste characteristics. A draft specification for the quality indicators of effervescent tablets based on enriched extraction has been proposed.Conclusion. In the course of the research work, the numerical indicators of medicinal plant raw materials were determined and its quality was confirmed, which enabled its use for further extraction. Extraction conditions were chosen, extracts were obtained. Excipients have been selected, the composition and technology of effervescent tablets based on the extracts of Aronia melanocarpa fruits have been developed, a draft specification for effervescent tablets has been proposed in accordance with the requirements of the State Pharmacopoeia of the Russian Federation, XIV edition.

Protein sample preparation for tissue distribution study.

The distribution and expression level of a protein among animal tissues is indicative of its possible roles. It is important to establish a generally applicable method to prepare protein samples with high-quality and achieve near 100% recovery of proteins from animal tissues. During preparation, to sufficiently dissolve and maintain stability of almost all proteins from tissues, as well as to avoid most contaminations affecting protein detection, 2×SDS Sample Buffer, sonication and trichloroacetic acid precipitation are applied. Here we provide a relatively simple, reproducible, and broadly applicable method for studying protein distribution in most tissues, in which the issues resulting from protein degradation and modification during sample preparation and assay interference by other cellular components like neutral lipids and glycogen could be overcome. Furthermore, this method represents the protein content by equal wet tissue mass, which is a better means to present the expression level of a protein in various tissues. High-quality protein samples from almost all tissues could be prepared. The samples produced are amenable to tissue distribution analysis by Western blotting and for silver/Coomassie staining, proteomics, and other protein analyses, which would contribute to potential biomarkers or treatments for a disease.

Acid-assisted oil extraction directly from thraustochytrids fermentation broth and its energy assessment for docosahexaenoic acid-enriched oil production

Thraustochytrids are the most prominent source of polyunsaturated fatty acids, specifically docosahexaenoic acid (DHA). Downstream processing constitutes a significant fraction of total production cost and thus needs judicious optimization. Currently, hazardous solvent-based extraction methods are used to extract oil from the dry or wet thraustochytrids cell mass. The process is also highly energy-intensive due to involvement of dewatering and drying as unit operations. Current work devised an energy-efficient acid-assisted extraction (AAE) methodology to overcome dry and wet biomass-based extraction limitations. AAE recovered 91 % of total oil with 35–40 % PUFA from the direct fermentation broth, eliminating the need for dewatering and drying of fermentation broth/cell biomass. The current work also presents an all-inclusive comparison of the energy assessment of oil extraction from dry and AAE method. AAE produced PUFA enriched oil with a total energy consumption of 210 MJ/kg, which was four times lower than that of conventional dry cell extraction methodology.

The Use of UV-vis Spectroscopy Technique for Investigation of Organic Compounds in Saccharine Substrates

Sugar substrates are rich in organic compounds. However, its concentration may vary depending on the culture. Thus, the objective of this work was to evaluate the composition of sugarcane and sorghum juices using the UV-vis technique. An evaluation of the composition of the substrates was carried out and a pre-inoculum with YPSAC 5% medium, where 0.10 grams of FT858 yeast was inoculated and kept incubated at 30°C for 24h at 250rpm. The cells were recovered by centrifugation, resulting in a concentration of 10 mg mL-1 of wet mass that was inoculated into 50 mL of the previously prepared fermentation medium with a concentration of 22°Brix and pH 5.0. Aliquots were taken for evaluation of molecular absorption spectra using a spectrophotometer (Global Trade Technology). These substrates are composed of water and fermentable sugars. The evaluation of the molecular absorption spectra showed a difference in the profile of the substrates as well as in the subsequent hours of fermentation, with a decrease in the intensity of the peaks being observed that may be related to the absorption of nutrients by the yeast. vis shows promise for this type of analysis.

A desert bee thermoregulates with an abdominal convector during flight.

Flying endothermic insects thermoregulate, likely to improve flight performance. Males of the Sonoran Desert bee, Centris caesalpiniae, seek females at aggregations beginning at sunrise and cease flight near midday when the air temperature peaks. To identify the thermoregulatory mechanisms for C. caesalpiniae males, we measured tagma temperature, wingbeat frequency, water loss rate, metabolic rate and tagma mass of flying bees across shaded air temperatures of 19-38°C. Surface area, wet mass and dry mass declined with air temperature, suggesting that individual bees do not persist for the entire morning. The largest bees may be associated with cool, early mornings because they are best able to warm themselves and/or because they run the risk of overheating in the hot afternoons. Thorax temperature was high (38-45°C) and moderately well regulated, while head and abdomen temperatures were cooler and less controlled. The abdominal temperature excess ratio increased as air temperature rose, indicating active heat transfer from the pubescent thorax to the relatively bare abdomen with warming. Mass-specific metabolic rate increased with time, and air and thorax temperatures, but wingbeat frequency did not vary. Mass-specific water loss rate increased with air temperature, but this was a minor mechanism of thermoregulation. Using a heat budget model, we showed that whole-body convective conductance more than doubled through the morning, providing strong evidence that the primary mechanism of regulating thorax temperature during flight for these bees is increased use of the abdomen as a convector at higher air temperatures.

Ischaemic preconditioning blunts exercise-induced mitochondrial dysfunction, speeds oxygen uptake kinetics but does not alter severe-intensity exercise capacity.

What is the central question of this study? Ischaemic preconditioning is a novel pre-exercise priming strategy. We asked whether ischaemic preconditioning would alter mitochondrial respiratory function and pulmonary oxygen uptake kinetics and improve severe-intensity exercise performance. What is the main finding and its importance? Ischaemic preconditioning expedited overall pulmonary oxygen uptake kinetics and appeared to prevent an increase in leak respiration, proportional to maximal electron transfer system and ADP-stimulated respiration, that was evoked by severe-intensity exercise in sham-control conditions. However, severe-intensity exercise performance was not improved. The results do not support ischaemic preconditioning as a pre-exercise strategy to improve exercise performance in recreationally active participants. We examined the effect of ischaemic preconditioning (IPC) on severe-intensity exercise performance, pulmonary oxygen uptake ( ) kinetics, skeletal muscle oxygenation (muscle tissue O2 saturation index) and mitochondrial respiration. Eight men underwent contralateral IPC (4×5min at 220mmHg) or sham-control (SHAM; 20mmHg) before performing a cycling time-to-exhaustion test (92% maximum aerobic power). Muscle (vastus lateralis) biopsies were obtained before IPC or SHAM and ∼1.5min postexercise. The time to exhaustion did not differ between SHAM and IPC (249±37vs. 240±32s; P=0.62). Pre- and postexercise ADP-stimulated (P) and maximal (E) mitochondrial respiration through protein complexes (C) I, II and IV did not differ (P>0.05). Complex I leak respiration was greater postexercise compared with baseline in SHAM, but not in IPC, when normalized to wet mass (P=0.01vs. P=0.19), mitochondrial content (citrate synthase activity, P=0.003vs. P=0.16; CI+IIP, P=0.03vs. P=0.23) and expressed relative to P (P=0.006vs. P=0.30) and E (P=0.004vs. P=0.26). The mean response time was faster (51.3±15.5vs. 63.7±14.5s; P=0.003), with a smaller slow component (270±105vs. 377±188mlmin-1 ; P=0.03), in IPC compared with SHAM. The muscle tissue O2 saturation index did not differ between trials (P>0.05). Ischaemic preconditioning expedited kinetics and appeared to prevent an increase in leak respiration through CI, when expressed proportional to E and P evoked by severe-intensity exercise, but did not improve exercise performance.

Benthic studies adjacent to Sakhalin Island, Russia, 2015 II: energy content of the zoobenthos in western gray whale feeding grounds

The waters adjacent to the northeastern coast of Sakhalin Island, Russia, are an important feeding ground for the endangered western gray whale. Data on the energy available to foraging whales from their prey resources is required for researchers interested in modeling the bioenergetics of whale foraging, but little energy content information is available for the benthic prey communities of gray whales in this region. In this study, we describe the energy density (ED), biomass, and total energy availability (ED × biomass) of benthic prey sampled from two gray whale foraging areas adjacent to Sakhalin Island: the nearshore and offshore feeding areas. ED varied almost seven-fold among benthic taxa, ranging from 1.11 to 7.62 kJ/g wet mass. Although there was considerable variation within most prey groups, amphipods had the highest mean ED of all of groups examined (5.58 ± 1.44 kJ/g wet mass). Small sample sizes precluded us from detecting any seasonal or spatial differences in mean ED within or among taxa; however, mean biomass in the offshore feeding area was, in some cases, an order of magnitude higher than mean estimates in the nearshore feeding area, resulting in higher mean total energy available to foraging gray whales offshore (958–3313 kJ/m2) compared to nearshore (223–495 kJ/m2). While the proportion of total energy accounted for by amphipods was variable, this prey group generally made up a higher proportion of the total energy available in the benthos of the offshore feeding area than in the benthos of the nearshore feeding area. Data presented here will be used to inform bioenergetics modeling of the vital rates of mature females in an effort to improve understanding of population growth limits for western gray whales.

The effect of rhizospheric bacteria Ochrobactrum cytisi IPA 7.2 on the resistance of white mustard plants to heavy metals and herbicides

In modern agriculture, the problem of the use of various pesticides, including non-selective herbicides and copper-containing fungicides, is acute. Rhizospheric bacteria can serve as one of the factors of increasing the resistance of plants to adverse chemical influences. The subject of this research was study the effect of bacteria Ochrobactrum cytisi IPA 7.2 on the white mustard (Sinapis alba L.) resistance to copper ions (Cu(II)), glyphosate and copper complexes with glyphosate [Cu(II)-GL]; as well as on the accumulation and translocation of pollutants in plants. It was shown that the combination of glyphosate or its complexes [Cu(II)-GL] and IPA 7.2 inoculation inhibited the growth of mustard more intensively than in the variants with pollutants alone. In the case of copper, on the contrary, an increase in the accumulation of wet and dry root mass by 1.8 times was found in inoculated plants. Colonization of mustard with strain IPA 7.2 reduced the accumulation of Cu(II) in the plant’s shoot system by two times and simultaneously stabilized the metal in the root zone. However, IPA 7.2 did not effect on the accumulation and translocation of chelated copper in the complexes. The current result is important for understanding about processes of interaction in the plant-rhizosphere bacteria-pollution system and can be used in the technology of growing environmentally friendly products.

New p-coumaric acid formulation in sustainable pest management; impact on soil bacterial diversity and N-cycle

Synthetic pesticides can pose a serious threat to the soil environment and are responsible for several adverse health effects in humans. The study aimed to assess the impact of a new formulation based on p-coumaric acid (p-CA) on the abundance, diversity, and structure of bacterial communities with the use of next-generation sequencing (NGS) of the 16S rRNA gene and quantitative PCR (qPCR). The commercial fungicide Porter 250 EC and a new formulation with p-CA as a natural bioactive substance were applied to arable soil in laboratory conditions. Neither difenoconazole nor the new plant protection product (PPP) (final concentration 0.03 μmol/g wet mass and 9.1 μmol/g wet mass, respectively) showed any significant effect (P < 0.05) on the bacterial biodiversity indices, nor did they show any effect on the abundance of bacteria associated with the N-cycle. However, detailed analyses revealed that both formulations significantly altered the structure of soil bacterial communities (P < 0.01). More bacterial phylotypes (50 versus 29) changed their abundance in soil treated with p-CA based formulation compared to Porter 250 EC after two weeks of treatment. After four weeks the changes caused by the new formulation were substantially less numerous (17 versus 50) than after two weeks which may favor the restoration of bacterial homeostasis at the end of the exposure period. Based on the results we can conclude that the new p-CA based formulation constitutes a promising product to be used in sustainable agriculture.

Understanding common dolphin and Australasian gannet feeding associations from nutritional and ethological perspectives

Abstract Prey detection and subsequent capture is considered a major hypothesis to explain feeding associations between common dolphins and Australasian gannets. However, a current lack of insight on nutritional strategies with respect to foraging behaviours of both species has until now, prevented any detailed understanding of this conspecific relationship. Here we combine stomach content analysis (SCA), nutritional composition of prey, a multidimensional nutritional niche framework (MNNF) and videography to provide a holistic dietary, nutritional, and behavioural assessment of the feeding association between dolphins and gannets in the Hauraki Gulf, New Zealand. Dolphins consumed ten prey species, including grey mullet (Mugil cephalus) as the most representative by wet mass (33.4%). Gannets preyed upon six species, with pilchards (Sardinops pilchardus) contributing most of the diet by wet mass (32.4%) to their diet. Both predators jointly preyed upon pilchard, jack mackerel (Trachurus spp.), arrow squid (genus Nototodarus), and anchovy (Engraulis australis). Accordingly, the MNNF revealed a moderate overlap in the prey composition niche (0.42) and realized nutritional niche (0.52) between dolphins and gannets. This suggests that both predators coexist in a similar nutritional space, while simultaneously reducing interspecific competition and maximizing the success of both encountering and exploiting patchily distributed prey. Behavioural analysis further indicated that dolphin and gannets feeding associations are likely to be mutually beneficial, with a carouselling foraging strategy and larger pod sizes of dolphins, influencing the diving altitude of gannets. Our approach provides a new, more holistic understanding of this iconic foraging relationship, which until now has been poorly understood.

Evaluating the Response of Hydrological Stress Indices Using the CHyM Model over a Wide Area in Central Italy

Central Italy is characterized by complex orography. The territorial response to heavy precipitation may activate different processes in terms of hydrogeological hazards. Floods, flash floods, and wet mass movements are the main ground effects triggered by heavy or persistent rainfall. The main aim of this work is to present a unique tool that is based on a distributed hydrological model, able to predict different rainfall-induced phenomena, and essential for the civil protection early warning activity. The Cetemps Hydrological Model is applied to the detection of hydrologically stressed areas over a spatial domain covering the central part of Italy during a weather event that occurred in 2014. The validation of three hydrological stress indices is proposed over a geographical area of approximately 64,500 km2 that includes catchments of varying size and physiography. The indices were used to identify areas subject to floods, flash floods, or landslides. Main results showed very high accuracies (~90%) for all proposed indices, with flood false alarms growing downstream to larger basins, but very close to zero in most cases. The three indices can give complementary information about the predominant phenomenon and are able to distinguish fluvial floods from pluvial floods. Nevertheless, the results were influenced by the presence of artificial reservoirs that regulated flood wave propagation, therefore, indices timing slightly worsen downstream in larger basins.

Neuromuscular mechanisms of weakness in a mouse model of chronic alcoholic myopathy.

Weakness is a common clinical symptom reported in individuals with chronic alcohol use disorder. However, it remains unclear whether low strength in these individuals is directly related to excessive ethanol intake, other deleterious factors (lifestyle, environment, genetics, etc.), or a combination of both. Therefore, we examined whether (and how) ethanol reduces the muscle's force-producing capacity using a controlled in vivo preclinical mouse model of excessive ethanol intake. To establish whether chronic ethanol consumption causes weakness, C57BL/6 female mice consumed 20% ethanol for 40 weeks (following a 2-week ethanol ramping period), and various measures of muscular force were quantified. Functional measures included all-limb grip strength and in vivo contractility of the left ankle dorsiflexors and plantarflexors. Once confirmed that mice consuming ethanol were weaker than age-matched controls, we sought to determine the potential neuromuscular mechanisms of muscle dysfunction by assessing neuromuscular excitation, muscle quantity, and muscle quality. Mice consuming chronic ethanol were 13 to 16% weaker (p≤ 0.016) than controls (i.e., mice consuming 100% water) with the negative impact of ethanol on voluntary grip strength(ƞ2 = 0.603) being slightly larger than that of electrically stimulated muscle contractility (ƞ2 = 0.482). Relative to controls, lean mass and muscle wet masses were 9 to 16% lower in ethanol-consuming mice (p≤ 0.048, ƞ2 ≥ 0.268). No significant changes were observed between groups for indices of neuromuscular excitation at the level of the motor unit, neuromuscular junction, or plasmalemma (p≥ 0.259, ƞ2 ≤ 0.097), nor was muscle quality altered after 40 weeks of 20% ethanol consumption (p≥ 0.695, ƞ2 ≤ 0.012). Together, these findings establish that chronic ethanol consumption in mice induces a substantial weakness in vivo that we interpret to be primarily due to muscle atrophy (i.e., reduced muscle quantity) and possibly, to a lesser degree, loss of central neural drive.

Aging characteristics of rice dried using microwave at 915 MHz frequency

AbstractBackground and ObjectivesRice aging is an intrinsic phenomenon that leads to physicochemical changes in rice kernels. The goal of this study is to determine the physicochemical properties of rice dried using a 915 MHz microwave and then aged. Two rice cultivars, a medium grain cultivar Titan and long grain hybrid cultivar XL753, with a harvest moisture content of 20% ± 1% (wet basis) were used for the study. The rice samples were treated with two different drying methods, natural air drying as control and microwave heating at 915 MHz frequency followed by tempering and natural air cooling at 25°C and 56% relative humidity (RH). Microwave‐dried samples were treated at specific energies ranging from 360 to 630 kJ/kg of initial wet grain mass (kJ/kg‐grain). Head rice samples were stored for 6 months at 4°C and 25°C representing nonaged and aged samples, respectively. Physicochemical properties of the samples were determined.FindingsAged microwave‐dried rice had significantly higher setback viscosity, cooked rice hardness and gumminess, and significantly lower peak viscosity and solid loss than nonaged rice. The changes in the viscosity profiles of aged microwave‐dried rice were generally similar to the trends recorded for aged control rice. Furthermore, aging significantly increased the water uptake and kernel elongation ratio of microwave‐dried rice cultivar XL753 but had no significant impact on rice cultivar Titan. Statistical models indicate that the solid loss of microwave‐dried rice decreases by 0.083% while the final viscosity, kernel elongation ratio, and hardness increase by 30 cP, 0.014, and 41 g respectively, with every degree Celsius increase in aging temperature (between 4°C and 25°C), when all other variables are kept constant. Also, aged microwave‐dried rice that were treated at 360 and 525 kJ/kg‐grain were practically equivalent in terms of hardness and solid loss.ConclusionsNatural aging of microwave‐dried rice (dried at 915 MHz frequency) led to changes in some physicochemical properties which were generally similar to the aging patterns of the control rice. Microwave specific energy of 525 kJ/kg‐grain is recommended for rice drying because it produces rice with desirable drying and aging properties.Significance and NoveltyThis study provides processing recommendations that can be used to select microwave parameters for rice drying, which will achieve desirable rice properties.

Municipal Sewage Sludge Composting in the Two-Stage System: The Role of Different Bulking Agents and Amendments

This study assessed the effect of different lignocellulosic amendments and bulking agents on compost stability (based on a 4 day respiration activity test, AT4, and self-heating factor, SHF) and maturity (based on the nitrification index Initr and the ratio of C in humic acids, HA, to total organic carbon, TOC, in compost, CHA/TOC). With all feedstock compositions (FCs), the share of sewage sludge was 79% (wet mass). For FC1, wood chips (13.5%) and wheat straw (7.5%) were used as bulking agents and amendments; for FC2, instead of wood chips, energy willow was added; for FC3, pine bark (13.5%) and conifer sawdust (7.5%) were used. All FCs produced stable and mature compost; however, with FC2, the thermophilic phase last 3 days longer than with the other FCs. Moreover, an AT4 value below 10 g O2/kg dry mass (d.m.) was obtained the earliest with FC2 (after 45 days, ca. 15–20 days earlier than with other FCs). With FC2, Initr below 0.5 was obtained in ca. 60 days, 10 days earlier than with FC3 and 30 days earlier than with FC1. The highest net increases in HS (86.0 mg C/g organic matter (OM)) and HA (56.3 mg C/g OM) were also noted with FC2; with other FCs, the concentrations of these compounds were from 1.3- to 1.5-fold (HS) and from 1.4- to 1.9-fold (HA) lower. With FC2, the highest CHA/TOC (15.5%) was also noted, indicating that this compost contained the largest share of the most stable form of organic carbon. The rates of OM removal in the bioreactor ranged from 7.8 to 10.1 g/(kg d.m.·day). The rates of SH and HA formation ranged from 1.63 to 4.83 mg C/(g OM·day) and from 1.23 to 1.80 mg C/(g OM·day), respectively. This means that, through the choice of the amendments and bulking agents, the length of the composting time needed to obtain a stable and mature product can be controlled.

A multiple-vehicle strategy for near-Earth asteroid capture

The use of asteroid resources could benefit future space missions. Instead of lifting the necessary materials off the Earth, they can be then sourced directly in space. Asteroid capture missions aim to bring asteroids closer to Earth, where they can be permanently accessed. This paper introduces a new strategy for asteroid capture missions, where two spacecraft are used for capturing near-Earth asteroids. These spacecraft act together as a ‘pitcher’ spacecraft and ‘catcher’ spacecraft, where the pitcher spacecraft hops from asteroid to asteroid and deflects them towards an orbit in the vicinity of Earth, while the catcher spacecraft is stationed at the Earth and captures the incoming asteroids. This novel two-spacecraft strategy is compared to a conventional one-spacecraft strategy using three analyses; a preliminary analysis using coplanar and circular orbits to define the problem, a statistical analysis using fictional near-Earth asteroids to obtain a large set of data, and an analysis where real near-Earth asteroids are used as mission targets. A mass model is developed to compute the retrieved asteroid mass per unit of initial wet spacecraft mass for missions aiming to retrieve multiple asteroids. Results show that the two-spacecraft strategy is capable of returning more asteroid mass and often at a shorter mission duration.