Stages Of Decomposition Research Articles

Decomposer faecal food web and C sequestration in soil. Can near infrared spectroscopy describe transfers and transformations from fresh organic inputs to protected forms in soil aggregates?

This study sought to characterize the transfer of agricultural organic inputs by macrofauna to the biogenic aggregate compartments of the soil and test the existence of a faecal food web process based on coprophagic feeding behaviours. In an experimental plantain crop field of Colombia, we applied the agroecological FBO (Fertilisation Bio Organique ®) technology, a nucleation technique which consists in planting perennial plants in 1.0 x 0.4 × 0.4 m deep trenches where low- and high-quality organic materials are added in a specific design, and endogeic earthworms are inoculated. We evaluated the effectiveness of Near Infrared Spectroscopy (NIRS) to track this flow of organic matter through different natural stages of decomposition represented by soil macroaggregates produced by soil macroinvertebrates as faecal pellets and casts. After one year, great part of the organic inputs had been either mineralized or incorporated into macroaggregates of different sizes and origins. Using NIRS and physicochemical laboratory analyses, we assessed the quality and quantity of organic matter in the different types of aggregates separated manually according to their origin: large biogenic aggregates (LBA), medium sized biogenic aggregates (MBA) and small biogenic aggregates (SBA); physical aggregates (PA), root aggregates (RA) and residual soil (RS).Earlier studies had shown that these structures were presumably formed by the activity of macroinvertebrates of three different functional groups, Diplopoda and Isopoda litter transformers for SBA, epidendogeic earthworms for MBA and mesohumic endogeic earthworms for LBA, organized in a feeding succession.A Coinertia analysis between showed significant covariation among the two sets of physico chemical (22 variables) and NIR spectral (100 different wavelength absorbances) characterization of 135 samples representative of the three classes of biogenic macroaggregates, physical aggregates and residual non macroaggregated soil, (RV = 0.55; p < 0.001). This analysis clearly separated biogenic structures and ranked them according to their size, from small SBA to medium sized MBA and large LBA. Physical PA aggregates and RS residual soil were projected close to the LBAs in the coinertia factorial plan. Multiple combinatorial data analysis CDA, associated 5 specific wavelength absorbance ranges with aggregate types and residual soil. Along the sequence from small to large biogenic aggregates, residual soil and physical aggregates, wavelengths associated to easily decomposed substrates (in ranges 1708–1716 nm; 1796–1948 and 2164–2316 nm) had progressively decreasing absorbances. Substrates associated to slowly decomposing aromatic, alkane and phenolic substrates either increased (1420–1436) or decreased (1284–1380) along this sequence.These results are compatible with the hypothesis of a progressive transformation and transfer of organic residues first into small biogenic aggregates that are presumably faecal pellets of Isopoda and Diplopoda, then to medium sized biogenic aggregates identified as casts of epiendogeic earthworms and finally to large biogenic aggregates expected to be the casts of the large endogeic earthworms present in these soils. A definitive verification of the hypothesis and the involvement of specific macroinvertebrates will require direct experimentation in controlled laboratory conditions.

Survival of Calliphora vicina (Diptera: Calliphoridae) embryos under cold temperature conditions: forensic implications.

Most blow flies (Diptera: Calliphoridae) species are sarcosaprophagous during the larval stage, primarily feeding on the soft tissues of carcasses during the early stages of decomposition, making them valuable forensic indicators for minimum post-mortem interval (minPMI) estimations. Like other insects, their developmental rates are strongly influenced by the environmental temperature. Although several studies have examined the influence of temperature on the development of different blow fly species, the impact of cold temperatures remains largely unstudied, despite its potential forensic implications. The present study investigates the effect of three cold temperatures (0, -2.5 and -5°C) on the survival of Calliphora vicina embryos of five different ages (0%, 20%, 40%, 60% and 80% of the total embryonic development) and two exposure times (6 and 24 h). Our results revealed significant differences in egg survival at the earliest embryonic stages (0% and 20% of the total embryonic development), resulting in high mortality rates. While at 20% of the total embryonic development high mortality was only observed under -5°C, at 0% of the total embryonic development high mortality rates were observed at all the temperatures tested. Although C. vicina embryos demonstrate tolerance to cold temperatures once they have completed the first 20% of the total embryonic development, potentially mitigating the impact of cold weather events, the possibility of minPMI underestimations due to the death of the first egg batches should not be disregarded. Additionally, considering that the embryonic development stages may last for several days under low temperatures, caution should be taken in the analysis of entomological evidence if a cadaver is discovered following cold weather episodes.

A pilot study on the isotopic characterization of feeding habits of Diptera in a tropical rain forest

Flies (Diptera) are among the most diverse groups of insects and are known to utilize various food resources, including plants, detritus, microbial tissues, and fresh and dead animal tissues. However, their feeding habits in the field remain poorly understood. We conducted a pilot study to apply stable nitrogen (N) and carbon (C) isotope techniques to examine the feeding habits of flies in a tropical rain forest in Sarawak, Malaysia. The fly samples comprised 13 families and >18 species. The results showed significant differences in nitrogen and carbon isotope ratios (δ15N and δ13C) among families and species within a family. The observed pattern is largely consistent with their known feeding habits; flies that use carcasses and carrion as diets (e.g., Sarcophagidae and Calliphoridae) have significantly higher δ15N values than those likely utilizing plant-based diets (e.g., Cecidomyiidae). There were significant differences in δ15N values among the six species of Calliphoridae, which is consistent with insect succession on carcasses. The differences in δ15N may be explained by the use of carrion at different stages of decomposition, because microbial decomposition can lead to the 15N enrichment. Tachinid flies had relatively low δ13C values, reflecting the use of lepidopterans as a host. This pilot study shows that the δ15N and δ13C values of flies provide insights into the diversity of feeding habits of fly communities, which could also serve as an indicator of resource availability in an entire ecosystem.

Insects on Decomposing Pigs and their Forensic Importance at a University in Nigeria

The use of insects to estimate post-mortem interval (PMI) of cadavers by forensic entomologists, is an innovative science enshrined in the medico-criminal system of the developed world. The science is dependent on the biology of insect species that are found in decomposing cadavers. Thus, insect species that are found on decomposing pigs as model to human cadaver, was studied during the rainy and dry seasons of 2021 in a University forest in Nigeria. The decomposition stages (fresh through skeletonization) of the pig cadavers were monitored, and insects found on them were collected with a sweep net, visually observed, and handpicked. They were identified morphologically using insect identification keys with the aid of a dissecting microscope. The tissues of the pig cadavers decomposed completely in 14 and 10 days, respectively, for dry and rainy seasons. Twenty-seven insect species belonging to the orders; Diptera, Coleoptera, and Hymenoptera were identified. The dipterans consist of the families Calliphoridae, Muscidae, Ulidiidae, and Stratiomyidae. The coleopteran families are the Carabidae, Chrysomelidae, Cleridae, Dermestidae, Histeridae, Scarabaeidae, and Staphylinidae, while Formicidae is the only family for the hymenopteran. The dipteran species were the first group to visit the cadavers during fresh, bloated, and wet decay stages while the coleopterans visited during wet and dry decay stages thus, creating a succession pattern on the cadavers. The insect species that aided the cadaver decomposition at different stages are discussed as forensic indicators, which could be useful as PMI estimators of the study area.

Formation and decomposition characteristics of CO2+TBAB hydrate for a safer CO2 storage

CO2 hydrate caps can effectively reduce the leakage risk from subsea CO2 sequestration. TBAB (tetrabutylammonium bromide) affects temperature and pressure required for the CO2 hydrate formation, which improves hydrate cap application. This study analyzes hydrate formation and decomposition characteristics in TBAB + CO2 system under different initial pressures and TBAB concentrations. The results show that the addition of TBAB effectively expand CO2 hydrate stable area and prevent CO2 leakage. 5 wt% TBAB not only provides crystal nucleus for hydrate formation and shortens the induction period, but also increases CO2 hydrate cap temperature to 290.3 K. The hydrate decomposition process in TBAB system is divided into CO2 ·nCO2 and TBAB·26H2O·nCO2 decomposition stage. Comparing with hydrate decomposition process in pure water system, it is found that TBAB mainly affects the second stage of hydrate decomposition process. In 5 wt% TBAB system, the hydrate decomposition process was affected by TBAB after more than 68 % hydrate decomposition. It is found that the hydrate decomposition rate with TBAB is almost 1/7 of that without TBAB. This study provides experimental support for expanding the application of CO2 hydrate caps, and provides a basis for determining the geological storage area of CO2 in sediments.

Modelling and optimization of epoxy-PMMA microcapsule synthesis parameter: A response surface methodology approach

The efficiency of self-healing microcapsule in restoring damages incurred by polymeric or composite materials is heavily dependent on modelling of encapsulation conditions to achieve optimized microcapsule with desired characteristics. This study modelled the effects of encapsulation conditions (core–shell ratio, agitation rate, and temperature) on the morphological, chemical, and thermal characteristics of epoxy-polymethylmethacrylate (epoxy-PMMA) microcapsules using response surface methodology (RSM). Epoxy-PMMA microcapsules were synthesized by encapsulating epoxy resin in polymethylmethacrylate (PMMA) at varied encapsulation conditions using solvent evaporation method. The morphology of the synthesized microcapsule using optical microscope (OP) revealed that the microcapsules are either mononuclear or irregular capsule types. The modelled effect showed that microcapsule percentage yield varied between 74.96 to 96.56%, was highly influenced by core–shell ratio and the effect of studied encapsulation conditions on percentage yield was best described by quadratic model. The core content of the microcapsules varied between 54.8 to 67.2%, observed to be highly influenced by both core–shell ratio and agitation rate which fit into linear model. The microcapsule average diameter was between 26 to 74 μm, highly influenced by agitation rate and fit linear model. Fourier transform infrared (FTIR) spectra of synthesized microcapsules revealed epoxy characteristic peak of C–O–C at 913 cm−1 and C–O-ph stretching at 1032 cm−1. C–O doublet of PMMA was observed at 1386 cm−1 and 1189 cm−1. Thermogravimetric analysis (TGA) of epoxy-PMMA microcapsule showed three stages of decomposition attributed to water evaporation, epoxy degradation, and PMMA shell degradation. Lastly, optimization process to achieve maximum yield, maximum core content and minimum capsule diameter was obtained with core–shell ratio of 1.5:3 and agitation rate of 1000 rpm at 40 °C. The synthesized epoxy-PMMA microcapsules exhibited chemical, thermal, morphological stability and the models can be optimized to achieve microcapsule with desired characteristics.

The state and structure of beech primaeval forests in the “Zacharovanyi Krai” National Nature Park

The relevance of the study is determined by the need to preserve natural values, which are considered the heritage of all mankind, namely the primaeval forests and old-growth beech forests of the UNESCO World Natural Heritage. The aim of the research was to study the state and structure of the beech primaeval forest in the national nature park “Zacharovanyi Krai”. For the study, a permanent sample plot of 1 ha (100×100 m) was laid down in the prevailing forest type – moist pure beech forest. This plot is located in the optimal forest-growing conditions for European beech (Fagus sylvatica L.) within the Vyhorlat-Hutyn volcanic ridge of the Ukrainian Carpathians. It was found that the beech forest stand on the plot is pure in composition and complex in form, characterised by different development phases (age groups by diameter): the first layer stand belongs to the mature age group (senile), the second layer – to the middle-aged group, and the third – to the pole (virginal). It was determined that 95% of the primaeval forest stock is the stock of the first layer, while the share of commercial trees of the first layer is 89% (66% of the total volume of stem wood of trees on the permanent sample plot). The main types of damage in the site are caused by abiotic factors. As a result of such damage, 43 m3‧ha-1 of deadwood was recorded, characterised by all 5 stages of decomposition. Under the canopy of the stand, 10,375 pcs‧ha-1 of undergrowth was recorded, of which the share of beech is 88%. Beech undergrowth is weakly differentiated by age groups: it was recorded only in the group of 7-year-olds and older and well-differentiated by height groups. By age group, undergrowth belongs to the juvenile-immature age state. The herbaceous cover is typical for nemoral forests. The presence of stationary research plots in the National Nature Park “Zakharovanyy Kray” makes it possible to constantly monitor the trends of natural development of the ecosystem – the beech primaeval forest

Speaking Deads: Sea Turtle Mortality Areas and Fisheries Overlaps Identified Through Backtracking of Stranded Carcasses in the Adriatic Sea

ABSTRACT Interaction with fishing gears represents the main anthropogenic threat at sea for sea turtles worldwide, and identifying the hotspots of turtle bycatch is a priority knowledge gap. Turtle stranding data represent a source of information about mortality areas at sea that are not fully exploited. This study aims to infer turtle mortality areas of turtles stranded along the Italian Adriatic Coast in the period 2019–2021 (1432 records), through backtrack modelling of carcasses. Specifically, the decomposition process of eight loggerhead carcasses was monitored, and the relationship between floating period (FP), turtle size and sea temperature was modelled through a generalized additive model. Oceanographic information was then used to track the routes of floating carcasses back, knowing their size and decomposition stage, and finally estimate the likely area of mortality. A complementary numerical experiment of connectivity between coastal and offshore areas gave indication that areas of potential mortality are relatively close to the coast, particularly in the northern Adriatic. Stranded turtles probably represent just a small fraction (17%–25%) of total at‐sea mortalities in the study area (Italian Adriatic waters), with decomposition rates, season and distance from shore influencing their stranding likelihood. Hence, strandings can inform only about spatio‐temporal variability of coastal mortality hotspots. Inferred areas of turtle mortality were most likely located in the North and Central Adriatic all over the year and overlap with heatmaps of fishing effort, obtained from vessel monitoring system (VMS) and automatic identification system (AIS) data, in the Gulf of Manfredonia and in the North‐West Adriatic in the cold (September–December) and warm (May–August) periods, respectively.

Pyrolysis kinetics of waste ryegrass under nitrogen and air atmosphere

To investigate the pyrolysis reaction of ryegrass, we conducted a simultaneous thermal analysis using thermogravimetric(TG) analyzers. This involved obtaining data through Thermogravimetry (TG), Derivative Thermogravimetry (DTG), and Differential thermal analysis (DTA) techniques. The experiments were conducted under dynamic nitrogen and air atmospheres at different heating rates. The kinetic parameters of ryegrass pyrolysis were determined using the Kissinger method, the Flynn-Wall-Ozawa (FWO) peak conversion rate approximate equivalence method, the Flynn-Wall-Ozawa (FWO) equal conversion rate method, and the Škvára-Šesták (S–S) method. It provides a theoretical basis for the reuse of ryegrass resources. The findings indicated that the pyrolysis temperature of ryegrass increased with the accelerated rate of temperature increase in both atmospheres. The average weight loss rate of pyrolysis of ryegrass in the air atmosphere (92.27 %) is higher than that compared to that in a nitrogen atmosphere (86.11 %). Additionally, the temperature required for complete decomposition is lower in the former case. The FWO peak conversion rate approximation equivalence approach and the FWO equal conversion rate method do not apply to the solution of the pyrolysis activation energy of ryegrass. The pyrolysis activation energy for the two decomposition stages, as calculated by the Kissinger method, is 165.73 and 185.86 kJ/mol−1 in the air atmosphere, and 219.99 and 277.02 kJ/mol−1 in a nitrogen atmosphere, respectively. The activation energy and mechanism function of ryegrass pyrolysis calculated by using the S–S method are as follows: [−ln(1−α)]2, 119.79, 104.31, 95.75, and 91.93 kJ/mol−1 in air atmosphere, (1−α)−1, 176.64, 67.89, 61.15, and 54.25 kJ/mol−1 in nitrogen atmosphere, respectively. The activation energy of ryegrass pyrolysis, as determined by both the Kissinger method and S–S method, was found to be higher under an air atmosphere compared to a nitrogen atmosphere.

Initial Litter Chemistry and UV Radiation Drive Chemical Divergence in Litter during Decomposition.

Litter's chemical complexity influences carbon (C) cycling during its decomposition. However, the chemical and microbial mechanisms underlying the divergence or convergence of chemical complexity under UV radiation remain poorly understood. Here, we conducted a 397-day field experiment using 13C cross-polarization magic-angle spinning nuclear magnetic resonance (13C-CPMAS NMR) to investigate the interactions among the initial chemistry, microbial communities, and UV radiation during decomposition. Our study found that the initial concentrations of O-substituted aromatic C, di-O-alkyl C, and O-alkyl C in Deschampsia caespitosa were higher than those in Kobresia tibetica. Litter's chemical composition exhibited divergent patterns based on the initial chemistry, UV radiation, and decay time. Specifically, D. caespitosa consistently displayed higher concentrations of di-O-alkyl C and O-alkyl C compared to K. tibetica, regardless of the UV exposure and decay time. Additionally, litter's chemical complexity was positively correlated with changes in the extracellular enzyme activities, particularly those involved in lignin, cellulose, and hemicellulose degradation, which accounted for 9%, 20%, and 4% of the variation in litter's chemical complexity, respectively. These findings highlighted the role of distinct microbial communities in decomposing different C components through catabolism, leading to chemical divergence in litter. During the early decomposition stages, oligotrophic Planctomycetes and Acidobacteria metabolized O-alkyl C and di-O-alkyl C under UV-blocking conditions. In contrast, copiotrophic Actinobacteria and Chytridiomycota utilized these components under UV radiation exposure, reflecting their ability to thrive under UV stress conditions due to their rapid growth strategies in environments rich in labile C. Our study revealed that the inherent differences in the initial O-alkyl C and di-O-alkyl C contributed to the chemical divergence, while UV radiation further influenced this divergence by shifting the microbial community composition from oligotrophic to copiotrophic species. Thus, differences in the initial litter chemistry, microbial community, and UV radiation affected the quantity and quality of plant-derived C during decomposition.

Insect Diversity on Decomposing Domestic Piglets (Sus domesticus ERXLEBEN) Carcasses at Umudike, Southeast Nigeria

Outdoor experiments were carried out to identify arthropods colonizing ground-placed and hung piglets (Sus domesticus) carcasses, their species diversity, and decomposition pattern. The trial was carried out in two seasons: July to September, 2019 (wet), and January to March, 2020 (dry) at Michael Okpara University of Agriculture, Umudike Abia State, Nigeria. A total of four healthy piglets with average weight of 3.73 kg were sacrificed for the trial. The piglets died by dislocating their cervical vertebrate (to mimic natural death); two were placed on the ground in metal cage whereas the other two were hung on a tree. Data on carcasses arthropod populations, temperature, weights and decomposition stages and rates were collected. Results showed that the total arthropod taxa of seventeen genera, ten families in four orders were recorded from the carcasses. A total of 29,629 individual insects were counted, belonging mainly to; Calliphoridae, Muscidae, Sarcophagidae, Dermestidae, Staphylinodea, Pyrrhocoridae and Formidae. Their species abundance was; Musca spp. (37.09 %), Chrysomya spp. (12.97 %), Pheidole spp. (12.09), Componotus spp. (9.69 %), Monomorium spp. (6.04 %), respectively. Higher number of insects were collected from ground-placed piglets (34.08%) than hung piglets (28.06%). More insects were recorded during the dry (55.28%) than wet (44.11%) season. Higher insect diversity was also recorded amongst insect species on ground-placed (0.80) than hung (0.72) carcasses. Data also showed that five stages (fresh, bloat, active decay, advanced decay and skeletonization) of decomposition were observed over a duration of 10 days. This study provided base-line data on the local insect fauna associated with the stages of decomposition with emphases on their arrival time, and it is crucial for estimating the post-mortem interval during forensic investigations in south eastern Nigeria.

A review of methods of age estimation based on postmortem computed tomography

Abstract Age at death is one of the key elements of the ‘biological profile’ prepared when analysing unidentified human remains. Biological age is determined according to physiological indicators and developmental stage, which can be determined by bone assessment. It is worth remembering that the researcher must interpret each case individually and in accordance with the current state of knowledge. One of the most developed tools for analysing human remains is postmortem computed tomography. This allows for the visualisation not only of bones without maceration but also of the entire body under various altered states, including corpses in advanced stages of decomposition and burnt bodies. The aim of this review is to present the current methods for age estimation based on postmortem computed tomography evaluation, comparing the results presented in 18 research projects published between 2013 and 2023 on foetuses, children, and adults from contemporary populations. Recent literature includes assessment of bones and characteristics such as skulls, teeth, vertebrae, pelvises, and long bones to estimate age at death. We cover the methods used in this recent literature, including machine learning, and discuss the advantages and disadvantages of them.

Microbial nutrient limitation and carbon use efficiency changes under different degrees of litter decomposition.

Alpine ecosystems are important terrestrial carbon (C) pools, and microbial decomposers play a key role in litter decomposition. Microbial metabolic limitations in these ecosystems, however, remain unclear. The objectives of this study aim to elucidate the characteristics of microbial nutrient limitation and their C use efficiency (CUE), and to evaluate their response to environmental factors. Five ecological indicators were utilized to assess and compare the degree of microbial elemental homeostasis and the nutrient limitations of the microbial communities among varying stages of litter decomposition (L, F, and H horizon) along an altitudinal gradient (2800, 3000, 3250, and 3500m) under uniform vegetation (Abies fabri) on Gongga Mountain, eastern Tibetan Plateau. In this study, microorganisms in the litter reached a strictly homeostatic of C content exclusively during the middle stage of litter decomposition (F horizon). Based on the stoichiometry of soil enzymes, we observed that microbial N- and P-limitation increased during litter degradation, but that P-limitation was stronger than N-limitation at the late stages of degradation (H horizon). Furthermore, an increase in microbial CUE corresponded with a reduction in microbial C-limitation. Additionally, redundancy analysis (RDA) based on forward selection further showed that microbial biomass C (MBC) is closely associated with the enzyme activities and their ratios, and MBC was also an important factor in characterizing changes in microbial nutrient limitation and CUE. Our findings suggest that variations in MBC, rather than N- and P-related components, predominantly influence microbial metabolic processes during litter decomposition on Gongga Mountain, eastern Tibetan Plateau.

Development and characterization of enhanced urea through micronutrients and established technology addition

AbstractIt is necessary to increase the agronomic use efficiency of urea to reduce ammonia volatilization and increase crop yield. However, relying solely on urea for the enhanced efficiency technologies development could harm fertilizer integrity, resulting in reduced application quality and fertilizer storage time. The authors aimed at developing and characterizing the physical, chemical, and physicochemical quality of a novel enhanced efficiency fertilizers, synthesized from urea plus boron (B), zinc (Zn), nickel (Ni), or molybdenum (Mo) addition, with or without N‐(n‐butyl) thiophosphoric triamide (NBPT) associated. Hygroscopicity, hardness, salt index (SI), pH, and thermogravimetric decomposition were the parameters evaluated. Fertilizer quality was assessed through microscopic X‐ray fluorescence, microtomography, and scanning electron microscopy. Micronutrients were added by coating or granulation; they were homogeneously distributed over the fertilizer's granules. The fertilizers’ hardness increased up to 86% with Zn coated compared with uncoated. Granulated urea with B, Zn, Ni, or Mo had greater internal porosity, which resulted in lower hardness. Boron and Zn addition to the fertilizers increased the hygroscopicity in average 388% and 473%, respectively, compared with hygroscopicity observed for urea. Moreover, hygroscopicity was increased by an average of 56% with NBPT addition. Micronutrients addition to the urea granules increased the SI, while thermal decomposition stages of urea were unaffected by micronutrients addition. Enhanced efficiency fertilizers require characterization before agronomic efficiency tests due to changes in their physical, chemical, and physicochemical properties. Unfavorable changes could harm granules integrity and application efficiency in the field, resulting in economic losses to the industry and farmers.

Litter decomposition in pure and mixed plantations on the Loess Plateau, China: Lack of home-field advantage

Litter decomposition plays a critical role in the nutrient cycling of terrestrial ecosystems. According to the home-field advantage (HFA) hypothesis, litter decomposes more rapidly in its home habitat (where it originates) compared to other habitats (referred to as away). Although this hypothesis has been widely tested in natural forests, it remains controversial and lacks support for plantations, especially in dry ecosystems where microbial activities are limited. To clarify it, the present study investigated litter mass loss, nutrient dynamics, and decomposer communities in a 549-day reciprocal transplant experiment of litter decomposition in Robinia pseudoacacia (RP) and Hippophae rhamnoides (HR) pure plantations and their mixed plantations (5:5 and 8:2 ratios) on the Loess Plateau, China. The rate of mass, carbon (C), nitrogen (N) and phosphorus (P) loss in litter differed depending on litter type of species component and plantation type they were placed in. HR litter lost mass and released C, N, and P fastest, irrespective of plantation type. The overall mass loss of the four litter types were the fastest under 5:5 mixed plantations. However, litter did not decompose more rapidly in its home soil compared to the away soil. The structural equation modeling revealed that initial litter quality played a significant role in regulating the loss of C and N across decomposition stages, while the climate variations and microbial chemistry also contributed to the process. The similarity in soil microbial communities across plantation types, along with the limited interaction between litter and microbes in arid environments, could help elucidate the lack of HFA, with other factors such as the litter type exerting a minor influence. In summary, this study does not substantiate the hypothesis of home-field advantage but supports its context-dependency. Thus, regional heterogeneity should be taken into account when predicting the carbon cycle of forest ecosystems in future studies.

16S rRNA, metagenomics and 2bRAD-M sequencing to decode human thanatomicrobiome

Microorganisms are essential in the decomposition of corpses and play a significant role in forensic science. However, previous studies have primarily focused on animal remains, specifically the gut, skin, and burial environment. Insufficient research has been conducted on the microbiota of human cadavers, especially in cases of advanced decomposition and additional tissues, resulting in a lack of relevant reference data. In this study, the microbiota of eight cadavers at different stages of decomposition were detected using 16S rRNA, metagenomic sequencing and 2bRAD-M sequencing. Nine different sites, including oral and nasal cavities, heart, liver, spleen, lung, kidney, muscle and gut, were analysed and the efficacy of these methods was evaluated. The results showed that 16S rRNA sequencing was the most cost-effective method for the study of cadavers in the early stages of decomposition, whereas for cadaveric tissues in the late stages of decomposition, 2bRAD-M could overcome host contamination more effectively than metagenomic sequencing. This paves the way for new opportunities in data retrieval and promotes in-depth investigations into the microbiota.

Carbon price forecasting using leaky integrator echo state networks with the framework of decomposition-reconstruction-integration

Carbon trading is one of the strategies to achieve the goal of dual carbon. However, carbon prices exhibit non-stationary and nonlinear characteristics, posing significant challenges for accurate forecasting. Inspired by the ideas of “division and conquest” and “granularity reconstruction”, a decomposition-reconstruction-integration framework is built for carbon price forecasting. The proposed model leverages a comprehensive ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and sample entropy (SE) to extract features from two perspectives of time and complexity, and thus the one-dimensional time series of carbon price is reconstructed into different items. Subsequently, leaky integrator echo state networks (LiESNs) are utilized to forecast each of these items individually. These individual forecasts are then integrated to generate the final point forecast. To evaluate the uncertainty of the point forecast, a Gaussian process model is applied to interval forecast. The proposed model comprehensively considers the time series features of carbon price including the temporal modal features in the decomposition stage, the entropy probability features in the reconstruction stage, and the essential temporal dependencies via dynamic reservoir of interconnected neurons in the integration forecasting stage. Experimental results demonstrate the model's exceptional forecasting performance, surpassing the effectiveness of alternative approaches.

Comparative Toxicological Analyses of Traditional Matrices and Blow Fly Larvae in Four Cases of Highly Decomposed Human Cadavers.

In forensic investigation, determining the time and cause of death becomes challenging, especially in cases where the remains are found in advanced decomposition, rendering traditional toxicological samples unavailable or unreliable. Entomotoxicology, an emerging methodology within forensic science, leverages insect specimens collected from cadavers as alternative toxicological samples. Several laboratory and field research studies have highlighted the efficacy in detecting various drugs, toxins, and elements absorbed by insects feeding on cadaveric tissues, even at low concentrations. However, correlation studies between drug concentrations in conventional matrices and insects remain controversial due to unknown factors influencing drug metabolism and larval feeding activity. This paper presents four real cases in which human cadavers were discovered in advanced stages of decomposition, and toxicological analyses were performed on both insect samples and available matrices. The results presented complement the scant literature currently available on the application of entomotoxicology in real cases, providing insights into the correlation between larvae and human specimen results. Furthermore, guidelines to collect and preserve entomological evidence at the crime scene and during the autopsy for use in entomotoxicological analyses are provided. This advancement holds promise in aiding forensic investigations, particularly in cases where traditional methods cannot be applied or require supporting data for further validation.

Novel 3D printing filaments: PLA and zinc carbonate basic composites for laser-assisted thermal decomposition

Additive manufacturing (AM), also known as 3D printing, has revolutionized the production of complex geometric structures across various industries. This study presents an innovative approach by integrating zinc carbonate basic (ZCB) precursor with polylactic acid (PLA) to develop composite filaments for fused deposition modeling (FDM) 3D printers. The resulting filaments undergo surface transformation into zinc oxide (ZnO) through high-power laser irradiation. Thermal analysis (TGA-DSC) and Fourier-transform infrared spectroscopy (FTIR) were used to confirm the decomposition of ZCB ([ZnCO₃]₂·[Zn(OH)₂]₃) into ZnO during the thermal decomposition stages. The study successfully extruded a composite filament containing 10% of ZCB, which worked adequately in 3D printing. The printed parts were analyzed through tensile tests (based on ASTM D638-5 standard), showing a notable difference in mechanical behavior between the commercial filament PLA and the composite filament (PLAC10). Laser irradiation of these samples facilitated a targeted conversion to ZnO, verified through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The integration of zinc oxide within the printed structures enhances structural stability and provides surfaces enriched with ZnO, a metal oxide with widely reported applications. Furthermore, an irradiated 3D-printed sample demonstrated chemo-resistive properties upon carbon monoxide (CO) exposure, underlining its potential as a gas sensor and confirming its semiconductor nature. This approach provides a cost-effective and efficient way to develop innovative devices with integrated functional materials.

Manufacturing and characterization of functionally gradient material from cemented carbide to diamond via filament-based material extrusion 3D printing

Functionally gradient material (FGM) fabricating via additive manufacturing draws great attention on alleviating the abrupt material discontinuity at the interface of different materials. Introducing gradient structure into polycrystalline diamond composites to produce diamond/cemented carbide FGM is an effective method to reduce the residual stress and enhance the bonding strength of diamond layer and cemented carbide substrate. However, achieving a smooth transition of material properties from cemented carbide to diamond is challenging. In this research, diamond/cemented carbide FGM with a well-controlled gradient was manufactured via filament-based material extrusion. Initially, green bodies of diamond/cemented carbide FGM were obtained by printing with customized composite filaments. Subsequently, thermal decomposition characteristic of the printing filament was analyzed by TGA, and the influence of different heating rates during the binder decomposition stage on the morphology and structure of the green bodies was investigated. After debinding, diamond/cemented carbide FGM without flaw was synthesized at 6.5 GPa and 1550℃. Subsequently, microstructure characterization was performed to investigate the distribution characteristics of the materials inside the diamond/cemented carbide FGM. A continuous transition from tungsten carbide to diamond was achieved inside the gradient layer. Furthermore, the stress state of diamond in different positions of the diamond/cemented carbide FGM was analyzed by Raman spectroscopy. It was found that all the residual stresses in the axial interface of the gradient layer were compressive stress, which can prevent occurrence of microcracks resulted from the tensile stresses formed in the interface. Finally, the impact tests reveal that gradient structure is conductive to improving the bond strength between PCD layer and cemented carbide substrate as the impact times before fracture of diamond/cemented carbide FGM has been increased by 15 %. The gradient structure design strategy, generated via the filament-based material extrusion technology, pioneers new ideas to the development of high-performance FGMs in mass production.