Biological Composition Research Articles

Study on quantitative analysis of bracket-induced nonlinear response of labio-cheek soft tissue during the orthodontic process

In the orthodontics process, intervention and sliding of an orthodontic bracket during the orthodontic process can arise large response of the labio-cheek soft tissue. Soft tissue damage and ulcers frequently happen at the early stage of orthodontic treatment. In the field of orthodontic medicine, qualitative analysis is always carried out through statistics of clinical cases, while quantitative explanation of bio-mechanical mechanism is lacking. For this purpose, finite element analysis of a three-dimensional labio-cheek-bracket-tooth model is conducted to quantify the bracket-induced mechanical response of the labio-cheek soft tissue, which involves complex coupling of contact nonlinearity, material nonlinearity and geometric nonlinearity. Firstly, based on the biological composition characteristics of labio-cheek, a second-order Ogden model is optimally selected to describe the adipose-like material of the labio-cheek soft tissue. Secondly, according to the characteristics of oral activity, a two-stage simulation model of bracket intervention and orthogonal sliding is established, and the key contact parameters are optimally set. Finally, the two-level analysis method of overall model and submodel is used to achieve efficient solution of high-precision strains in submodels based on the displacement boundary obtained from the overall model calculation. Calculation results with four typical tooth morphologies during orthodontic treatment show that: ① the maximum strain of soft tissue is distributed along the sharp edges of the bracket, consistent with the clinically observed profile of soft tissue deformation; ② the maximum strain of soft tissue is reduced as the teeth align, consistent with the clinical manifestation of common damage and ulcers at the beginning of orthodontic treatment and reduced patient discomfort at the end of treatment. The method in this paper can provide reference for relevant quantitative analysis studies in the field of orthodontic medical treatment at home and abroad, and further benefit to the product development analysis of new orthodontic devices.

First report on the bacterial community composition, diversity, and functions in Ramsar site of Central Himalayas, Nepal.

Wetland bacterial communities are highly sensitive to altered hydrology and the associated change in water physicochemical and biological properties leading to shifts in community composition and diversity, hence affecting the ecological roles. However, relevant studies are lacking in the wetlands of central Himalayas Nepal. Thus, we aimed to explore the variation of bacterial communities, diversity, and ecologic functions in the wet and dry periods of a wetland (designed as Ramsar site, Ramsar no 2257) by using 16S rRNA gene-based Illumina MiSeq sequencing. We reported a pronounced variation in water physicochemical and biological properties (temperature, pH, Chla, DOC, and TN), bacterial diversity, and community composition. Bacterial communities in the dry season harbored significantly higher alpha diversity, while significantly higher richness and abundance were reflected in the wet season. Our results uncovered the effect of nutrients on bacterial abundance, richness, and community composition. Fourteen percent of the total OTUs were shared in two hydrological periods, and the largest portion of unique OTUs (58%) was observed in the dry season. Planctomycetes and Bacteroidetes dominated the wet season exclusive OTUs; meanwhile, Actinobacteria dominated the dry season exclusive OTUs. Bacteria in these wetlands exhibited divergent ecological functions during the dry and wet seasons. By disclosing the variation of water bacterial communities in different hydrologic periods and their relationship with environmental factors, this first-hand work in the Ramsar site of Nepal will develop a baseline dataset for the scientific community that will assist in understanding the wetland's microbial ecology and biogeography.

Spatial-Temporal Heterogeneity in Large Three-Dimensional Nanofibrillar Cellulose Hydrogel for Human Pluripotent Stem Cell Culture

One approach to cell expansion is to use large hydrogel for growing a large number of cells. Nanofibrillar cellulose (NFC) hydrogel has been used for human induced pluripotent stem cell (hiPSCs) expansion. However, little is known about the status of hiPSCs at the single cell level inside large NFC hydrogel during culture. To understand the effect of NFC hydrogel property on temporal-spatial heterogeneity, hiPSCs were cultured in 0.8 wt% NFC hydrogel with different thicknesses with the top surface exposed to the culture medium. The prepared hydrogel exhibits less restriction in mass transfer due to the presence of macropores and micropores interconnecting the macropores. More than 85% of cells at different depths survive after 5 days of culture inside 3.5 mm thick hydrogel. Biological compositions at different zones inside the NFC gel were examined over time at a single-cell level. A dramatic concentration gradient of growth factors estimated in the simulation along 3.5 mm NFC hydrogel could be a reason for the spatial-temporal heterogeneity in protein secondary structure and protein glycosylation and pluripotency loss at the bottom zone. pH change caused by the lactic acid accumulation over time leads to changes in cellulose charge and growth factor potential, probably another reason for the heterogeneity in biochemical compositions. This study may help to develop optimal conditions for producing high-quality hiPSCs in large nanofibrillar cellulose hydrogel at scale.

Дослідження біологічної цінності та нутрієнтного складу медового десерту

The article defines the biological value of honey dessert and its nutritional composition (content of vitamins, macro- and microelements, flavonoids, etc.). Honey dessert, which consisted of 65% sunflower honey, 30% bee pollen and 5% amaranth seeds, which were added in the form of flour, was used for research. Generally accepted research methods were used in accordance with national and international standards. The type of honey was confirmed by the method of pollen analysis, experimental studies were carried out on the basis of the National University of Bioresources and Nature Management of Ukraine and the NSC "Institute of Beekeeping named after P. I. Prokopovych". The biological value and nutrient composition of honey desserts with bee honey and amaranth seeds provided by the producers of the NGO "Beekeepers’ Women’s Foundation" were investigated. The content of vitamins, organic acids, squalene, flavonoids, macro- and micronutrients was determined. The predominant amount of citric (323.2 mg/kg) and oxalic (286.0 mg/kg) organic acids was noted. Potassium and magnesium accounted for 79.0% of the mineral composition of the honey dessert. The obtained indicators indicated the high quality of the honey dessert, as well as the expediency of its use in health and functional human nutrition. According to the determined indicators, the honey dessert contains 25 to 50 percent of the daily norm of necessary nutrients for human consumption. The practical value of the performed work is the use of research results for the development of human diets, production of new food products, and for the in-depth study of the impact of honey desserts on the human body.

Assessing the Larvicidal Properties of Endemic Campeche, Mexico Plant Piper cordoncillo var. apazoteanum (Piperaceae) against Aedes aegypti (Diptera: Culicidae) Mosquitoes

The research aims to investigate the mortality effect of essential oil from Piper cordoncillo var. apazoteanum, an endemic plant from Campeche, Mexico, on early second-instar Aedes aegypti larvae; it also aims to identify the volatile compounds present in the fresh leaves of the plant. To test the effectiveness of the essential oil, we followed World Health Organization Standard Procedures. Larvae were observed for 17 consecutive days after treatment to determine the mortality and growth-inhibitory effect exerted by the essential oil. The results showed that the essential oil was effective in controlling mosquito populations. At a concentration of 800 ppm, the oil achieved an effectiveness rate of 70.00 ± 8.16% after 24 h, increasing to 100.00 ± 0.01% mortality after 72 h. With a concentration of 400 ppm, the effectiveness was 98.33 ± 0.17% by the end of the experiment. Furthermore, the obtained results demonstrated that the LC50 value was 61.84 ± 6.79 ppm, while the LC90 value was 167.20 ± 11.49 ppm. Essential oil concentrations inhibited the growth of immature insect stages, with concentrations between 800-100 ppm demonstrating very high inhibitory activity, and the lowest concentration of 50 ppm showing high inhibitory activity. The study also identified 24 chemical compounds representing 86.71% of the volatile compound composition of the fresh leaves of P. cordoncillo; the most abundant compounds were Safrole, Caryophyllene oxide, E-Nerolidol, and Calarene epoxide. The method used to extract the volatile compounds, solvent-free microwave extraction (SFME), is a promising alternative to traditional methods that avoids the use of potentially harmful solvents, making it more ecologically friendly and potentially safer for professionals handling the extracted compounds. Overall, the study demonstrates the potential of P. cordoncillo essential oil as an effective means of controlling mosquito populations, and provides valuable information on the chemical composition of the plant.Moreover, our study is the first to report on the biological activity and chemical composition of P. cordoncillo worldwide.

Development of optimised tissue-equivalent materials for proton therapy

Objective. In proton therapy there is a need for proton optimised tissue-equivalent materials as existing phantom materials can produce large uncertainties in the determination of absorbed dose and range measurements. The aim of this work is to develop and characterise optimised tissue-equivalent materials for proton therapy. Approach. A mathematical model was developed to enable the formulation of epoxy-resin based tissue-equivalent materials that are optimised for all relevant interactions of protons with matter, as well as photon interactions, which play a role in the acquisition of CT numbers. This model developed formulations for vertebra bone- and skeletal muscle-equivalent plastic materials. The tissue equivalence of these new materials and commercial bone- and muscle-equivalent plastic materials were theoretical compared against biological tissue compositions. The new materials were manufactured and characterised by their mass density, relative stopping power (RSP) measurements, and CT scans to evaluate their tissue-equivalence. Main results. Results showed that existing tissue-equivalent materials can produce large uncertainties in proton therapy dosimetry. In particular commercial bone materials showed to have a relative difference up to 8% for range. On the contrary, the best optimised formulations were shown to mimic their target human tissues within 1%–2% for the mass density and RSP. Furthermore, their CT-predicted RSP agreed within 1%–2% of the experimental RSP, confirming their suitability as clinical phantom materials. Significance. We have developed a tool for the formulation of tissue-equivalent materials optimised for proton dosimetry. Our model has enabled the development of proton optimised tissue-equivalent materials which perform better than existing tissue-equivalent materials. These new materials will enable the advancement of clinical proton phantoms for accurate proton dosimetry.

Studying Oral Tissue via Real-Time High-Resolution Terahertz Spectroscopic Imaging

Terahertz (THz) waves are extremely sensitive to water content and biological composition (proteins, genes, and metabolites), which are the key regulator of cancer development. Hence, the application of THz spectroscopy and imaging is promising in the field of biomedicine, especially in cancer diagnosis. Currently, the diagnosis of cancer patients (including tumor borders, tumor stage, etc.) mainly rely on optical microscope observation of pathological slices. The preparation of the slices is complicated and time consuming, and the microscopic field of view is small, which cannot effectively guide the precise removal of the tumor during the operation in time. To solve this problem, a label-free real-time high-resolution near-field THz spectroscopy imaging technique was developed. In this study, we successfully apply this technique to the oral tissue. Compared with conventional point-by-point scanning terahertz time-domain spectroscopy imaging, this technique can exhibit a real-time imaging rate (as high as 20 frames/s at 512 \ifmmode\times\else\texttimes\fi{} 1024 pixels) and a field of view approximately 5 mm in diameter with a spatial resolution up to \ensuremath{\lambda}/10 at 1 THz in near-field condition. The experimental results show that the terahertz spectroscopic imaging in this paper can clearly detect and identify not only biological tissues with different components, but also normal and cancerous tissues, as well as tissues with the same composition but different slice directions. This work lays an experimental foundation for the application of THz spectroscopy imaging to rapid label-free intraoperative diagnosis, and it provides a basis for promoting the wide application of THz technology in the biomedical field.

Mid-late holocene accretional history of low-lying, coral-reef rim islets, South-Marutea Atoll, Tuamotu, central South Pacific: The key role of marine hazard events

South-Marutea Atoll is located in the Gambier Island Group, at the south-eastern end of the Tuamotu Archipelago, French Polynesia, central South Pacific. Understanding the modalities of islet building from low-lying atolls over the mid to late Holocene, in relation to sea-level changes and cycles of marine hazard events, is a prerequisite for better anticipate future geomorphic changes to which the islets will likely be faced in the next decades under global climate warming. Herein is presented the depositional history of two selected atoll islets, based on chronostratigraphic analysis of sedimentary, coral-dominated sequences from six excavations. Identified as Motu Aramu and Motu Vainono, these islets are located respectively in north-north-east and due south of the atoll rim. Additional surficial sampling was conducted on modern ocean-facing shingle ridges, respectively on north-north-west (Motu Oire), west (Motu Aranui) and east (Motu Tekava) rim areas, in order to date the latest ridge-emplacement stages. Oire and Aranui sites, located along the leeward atoll sites, are protected from trade winds, Aramu, Vainono and Tekava are located on the windward sides, directly exposed to northeasterly and southeasterly storm swells respectively. A total of 88 coral clasts were collected to be U/Th dated. The excavated sequences range between 2.50 ​m and 0.90 ​m in thickness, from the outer islet sides lagoonwards. Five lithofacies, including two subfacies, were recognized based on texture and biological composition: a coral boulder-cobble-dominated, a coral pebble-dominated – pebble-supported and sand-supported subfacies – and a foraminifera-rich, sand-dominated and an organic-rich, pebble to sand facies. These facies tend to be distributed from ocean sides landwards according to a decreasing grain-size gradient. A model of atoll-island accretion emerges in relation with changes in frequency and intensity of marine hazard events. The islet foundations consist of conglomerate platforms, locally up to 1.0 ​m thick, deposited from about 5,000 to 1,000 ​calendar year (cal yr) BP. Islets began to accrete from 5,000 ​yr cal BP. While at Motu Vainono, islet building occurred continuously over the last 5,000 years, at Motu Aramu, there is an apparent non-depositional episode, from 4,000 to 2,000 ​yr cal BP, interpreted as caused by a marked decreased in enso-related cyclone activity. The outer shingle ridges in all studied sites were regularly reshaped during the last millennium. During the last 5,000 years, the major accretion-islet episodes occurred irrespective of the course of sea level, indicating that sea-level change was not a driver of islet accretion. Periodical, marine high-energy events clearly appear to be the key controls of islet shaping. Shifts of cyclone source areas further south and increasing cyclone intensity, but lower frequency, due to enhanced enso variability throughout the 21st century, is postulated to expose the Gambier island Group to stronger, but fewer disturbance events when compared to the last millennia.

Biological Activities and Chemical Composition of Essential Oil from Hedyosmum purpurascens (Todzia)—An Endemic Plant in Ecuador

Hedyosmum purpurascens is an endemic species found in the Andes of Ecuador and it is characterized by its pleasant smell. In this study, essential oil (EO) from H. purpurascens was obtained by the hydro-distillation method with a Clevenger-type apparatus. The identification of the chemical composition was carried out by GC-MS and GC-FID in two capillary columns, DB-5ms and HP-INNOWax. A total of 90 compounds were identified, representing more than 98% of the total chemical composition. Germacrene-D, ϒ-terpinene, α-phellandrene, sabinene, O-cymene, 1,8-cineole and α-pinene accounted for more than 59% of the EO composition. The enantioselective analysis of the EO revealed the occurrence of (+)-α-pinene as a pure enantiomer; in addition, four pairs of enantiomers were found (α-phellandrene, o-cymene, limonene and myrcene). The biological activity against microbiological strains and antioxidants and the anticholinesterase properties were also evaluated and the EO showed a moderate anticholinesterase and antioxidant effect, with an IC50 value of 95.62 ± 1.03 µg/mL and a SC50 value of 56.38 ± 1.96. A poor antimicrobial effect was observed for all the strains, with MIC values over 1000 µg/mL. Based on our results, the H. purpurasens EO presented remarkable antioxidant and AChE activities. Despite these promising results, further research seems essential to validate the safety of this medicinal species as a function of dose and time. Experimental studies on the mechanisms of action are essential to validate its pharmacological properties.

The functional diversity of fish assemblages in the vicinity of oil and gas pipelines compared to nearby natural reef and soft sediment habitats

As the offshore hydrocarbon industry matures and decommissioning activities are expected to increase, there is a requirement to assess the environmental consequences of different pipeline decommissioning options. Previous research on fish and other ecological components associated with pipelines has focused on examining species richness, abundance and biomass surrounding structures. The extent to which subsea pipelines mimic or alter ecosystem function compared with nearby natural habitats is unknown. We analyse differences in fish assemblage biological trait composition and the functional diversity at exposed shallow-water subsea pipelines, nearby natural reef and soft sediment habitats, using mini stereo-video remotely operated vehicles (ROV). Habitats significantly differed in assemblage trait composition. The pipeline and reef habitats shared a more similar functional composition and had the presence of key functional groups required for the development and maintenance of healthy coral reef systems. The reef habitat had the greatest functional diversity, followed by the pipeline habitat and soft sediment habitat respectively.

Methodology of formation of the hydrosphere state management system in technogenically-loaded regions of Russia

The condition of the underground and surface hydrosphere as one of the shells of the human habitat plays an exceptional role in ensuring the normal functioning of the population. In Russian regions with developed industry and transport infrastructure, the hydrosphere is experiencing significant man-made loads, which are objectively characterized by saturation of its facilities with various industrial and household effluents containing harmful and toxic substances, including heavy metals and their compounds. The article presents the results of the development of a hydraulic network management system in these territories. Scientifically grounded approaches to the formation of an appropriate methodology for the construction of control subsystems are presented. In particular, the complex of integrated system analysis and synthesis was chosen as the basic analytical tools, which allows taking into account the fundamental properties of natural and technical systems. It is shown that effective control of the hydrosphere can be carried out only with the joint synchronous functioning of the control and regulating blocks. The regional system, built according to the proposed scheme, allows you to quickly develop and implement organizational and technical measures to normalize the chemical and biological composition of drainage waters.

Chemical Composition and Biological Activities of Eucalyptus globulus Essential Oil.

Eucalyptus globulus essential oil (EGEO) is considered as a potential source of bioactive compounds with significant biological activity. The aim of this study was to analyze the chemical composition of EGEO, in vitro and in situ antimicrobial activity, antibiofilm activity, antioxidant activity, and insecticidal activity. The chemical composition was identified using gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The main components of EGEO were 1,8-cineole (63.1%), p-cimene (7.7%), a-pinene (7.3%), and a-limonene (6.9%). Up to 99.2% of monoterpenes were present. The antioxidant potential of essential oil and results indicate that 10 μL of this sample can neutralize 55.44 ± 0.99% of ABTS•+, which is equivalent to 3.22 ± 0.01 TEAC. Antimicrobial activity was determined via two methods: disk diffusion and minimum inhibitory concentration. The best antimicrobial activity was shown against C. albicans (14.00 ± 1.00 mm) and microscopic fungi (11.00 ± 0.00 mm-12.33 ± 0.58 mm). The minimum inhibitory concentration showed the best results against C. tropicalis (MIC 50 2.93 µL/mL, MIC 90 3.17 µL/mL). The antibiofilm activity of EGEO against biofilm-forming P. flourescens was also confirmed in this study. The antimicrobial activity in situ, i.e., in the vapor phase, was significantly stronger than in the contact application. Insecticidal activity was also tested and at concentrations of 100%, 50%, and 25%; the EGEO killed 100% of O. lavaterae individuals. EGEO was comprehensively investigated in this study and information regarding the biological activities and chemical composition of the essential oil of Eucalyptus globulus was expanded.

The biological and biochemical composition of wheat (Triticum aestivum) as affected by the bio and organic fertilizers

Microorganisms and organic compounds (humic and fulvic acid) offer viable alternatives to insecticides and mineral fertilizers. Even though many studies have shown the effects of biofertilizers and organic substances separately, little information is available on plant responses to the combined application of these bio-stimulants, even though these biological inputs have a high potential for simultaneous action. A two-year (2020/21–2021/22) field experiment was conducted to investigate the impact of organic and biofertilizers application on the growth, yield, and biochemical attributes of wheat (cv. Misr-1). Pre-planting, wheat seeds were inoculated with two biofertilizers including Mycorrhizae, and Azotobacter, and their combination (MIX), and control (un-inoculation) were considered the main plot factor. The subplot factor contained the foliar sprays of humic acid, fulvic acid, and control (no spray). The results revealed that the seed inoculation with mycorrhizae and azotobacter in combination with foliar-applied humic acid markedly (p ≤ 0.05) affected the growth, yield, and seed biochemical composition of wheat. Combination of mycorrhiza and azotobacter significantly (p ≤ 0.05) increased) plant height (100 cm), crop growth rate (18.69 g), number of spikelets per spike (22), biological yield (13.4 ton ha-1), grain yield (5.56 ton ha-1), straw yield (8.21 ton ha-1),), nitrogen (2.07%), phosphorous (0.91%), potassium (1.64%), protein content (12.76%), starch (51.81%), and gluten content (30.90%) compared to control. Among organic fertilizers, humic acid caused the maximum increase in plant height (93 cm), crop growth rate ( 15 g day-1 m-2),1000 grain weight (51 g), biological yield ( 11ton ha-1), grain yield (4.5 ton ha-1), protein content (11%), chlorophyll content (46 SPAD), and gluten (29.45%) as compared to all other treatments. The foliar application of humic acid combined with the mycorrhizae or azotobacter seed inoculation was efficient to induce wheat vegetative growth development, as well as yield and its components.

Diversity of the Pteridoflora of Montane Northwestern Mexico

This study compiles and updates the checklist of ferns and lycophytes from the Sierra Madre Occidental (SMOc). For this, we revised information on these taxa from regional floristic studies, databases, and herbaria. Our updated list includes 312 species, of which 276 are ferns and 36 are lycophytes integrated into 27 families and 75 genera. The richest families are Pteridaceae (118), Polypodiaceae (31), Selaginellaceae (30), Aspleniaceae (25), and Dryopteridaceae (25). The three most diverse genera were Selaginella (30), Asplenium (25), and Myriopteris (22). The species-rich Mexican states that include the SMOc are Durango (166 species), Chihuahua (149), and Jalisco (146). As in other tropical mountains, species richness in the SMOc is concentrated at the elevation interval of 1500 to 2000 m (236 species). The mid-mountain vegetation forests (Quercus and Pinus-Quercus forests) harbor the most pteridoflora richness (52% of the species). Four species of ferns are listed as threatened in the Mexican Official Norm NOM-059-SEMARNAT-2010, 17 species are listed in the IUCN, and only one tree ferns are in CITES. The SMOc has a Nearctic affinity, and its fern and lycophyte diversity are lower than in other Mexican Transition Zone mountain chains, such as the Sierra Madre del Sur, the Trans-Mexican Volcanic Belt, and the Sierra Madre Oriental. Notwithstanding, its biological composition is unique and distinctive. The species number reported in the SMOc represents 31% of the pteridoflora diversity recorded in Mexico.

Structural features, intrinsic disorder, and modularity of a pyriform spidroin 1 core repetitive domain.

Orb-weaving spiders produce up to seven silk types, each with distinct biological roles, protein compositions, and mechanics. Pyriform (or piriform) silk is composed of pyriform spidroin 1 (PySp1) and is the fibrillar component of attachment discs that attach webs to substrates and to each other. Here, we characterize the 234-residue repeat unit (the "Py unit") from the core repetitive domain of Argiope argentata PySp1. Solution-state nuclear magnetic resonance (NMR) spectroscopy-based backbone chemical shift and dynamics analysis demonstrate a structured core flanked by disordered tails, structuring that is maintained in a tandem protein of two connected Py units, indicative of structural modularity of the Py unit in the context of the repetitive domain. Notably, AlphaFold2 predicts the Py unit structure with low confidence, echoing low confidence and poor agreement to the NMR-derived structure for the Argiope trifasciata aciniform spidroin (AcSp1) repeat unit. Rational truncation, validated through NMR spectroscopy, provided a 144-residue construct retaining the Py unit core fold, enabling near-complete backbone and side chain 1H, 13C, and 15N resonance assignment. A six α-helix globular core is inferred, flanked by regions of intrinsic disorder that would link helical bundles in tandem repeat proteins in a beads-on-a-string architecture.

Role of Nanoparticles against Diabetes Mellitus and Cancer

According to WHO, there are about 422 million diabetes patients throughout the world. Diabetes Mellitus is a metabolic disorder that results from hyperglycemia due to abnormal secretion and action of insulin. Diabetes is characterized into type 1 diabetes, type 2 diabetes and gestational diabetes. According to the survey of WHO in 2017, there are 3.2 million people suffering from cancer and 8.8 million deaths from cancer around the globe. About 90-95% cancer is due to lifestyle factors. There are six major indications of cancer that required forming a malignant tumor. Treatments based on nanotechnology, such as the creation of nanoscale medication delivery, can enable accurate cancerous tissue targeting while minimizing adverse effects. Nanoparticles can easily overcome cell barriers due to their biological composition. Although numerous treatments can be used to treat tumors, their sensitivity often results in insufficient outcomes and can cause a variety of adverse effects, including damage to normal cells.

How to Statistically Disentangle the Effects of Environmental Factors and Human Disturbances: A Review

Contemporary biological assemblage composition and biodiversity are often shaped by a range of natural environmental factors, human disturbances, and their interactions. It is critical to disentangle the effects of individual natural variables and human stressors in data analysis to support management decision-making. Many statistical approaches have been proposed and used to estimate the biological effects of individual predictors, which often correlated and interacted with one another. In this article, we review nine of those approaches in terms of their strengths, limitations, and related r packages. Among those are hierarchical partitioning, propensity score, the sum of AIC weights, structural equation modeling, and tree-based machine learning algorithms. As no approach is perfect, we offer two suggestions: (1) reducing the number of predictors as low as possible by carefully screening all candidate predictors based on biological and statistical considerations; (2) selecting two or more approaches based on the characteristics of the given dataset and specific research goals of a study, and using them in parallel or sequence. Our review could help ecologists to navigate through this challenging process.

A Review of 3D Polymeric Scaffolds for Bone Tissue Engineering: Principles, Fabrication Techniques, Immunomodulatory Roles, and Challenges.

Over the last few years, biopolymers have attracted great interest in tissue engineering and regenerative medicine due to the great diversity of their chemical, mechanical, and physical properties for the fabrication of 3D scaffolds. This review is devoted to recent advances in synthetic and natural polymeric 3D scaffolds for bone tissue engineering (BTE) and regenerative therapies. The review comprehensively discusses the implications of biological macromolecules, structure, and composition of polymeric scaffolds used in BTE. Various approaches to fabricating 3D BTE scaffolds are discussed, including solvent casting and particle leaching, freeze-drying, thermally induced phase separation, gas foaming, electrospinning, and sol-gel techniques. Rapid prototyping technologies such as stereolithography, fused deposition modeling, selective laser sintering, and 3D bioprinting are also covered. The immunomodulatory roles of polymeric scaffolds utilized for BTE applications are discussed. In addition, the features and challenges of 3D polymer scaffolds fabricated using advanced additive manufacturing technologies (rapid prototyping) are addressed and compared to conventional subtractive manufacturing techniques. Finally, the challenges of applying scaffold-based BTE treatments in practice are discussed in-depth.

ECOLOGICAL WATER QUALITY

Water quality – is a description of water’s chemical and biological composition and physical properties, which characterize it as an abiotic component of aquatic ecosystem and determine its suitability for specific consumption purposes.
 Ecological water quality (environmental water quality) – refers to the ecological well-being of an aquatic ecosystem, with the main focus on protection of the aquatic environment and human life and health. It comprises a complex of physical, chemical, biological and other parameters reflecting specific features of abiotic and biotic components of aquatic ecosystems.
 The requirements for physical, chemical and biological properties of water are set in the water quality standards, which may be developed by particular countries or introduced by international organizations.
 Ecological water quality depends upon natural and human factors. Natural factors are in their turn divided into abiotic (for example, geological, meteorological, hydrological) and biotic (for example, the ratio of primary production and organic matter destruction). The main human factors affecting water quality include artificial modification of aquatic ecosystems’ hydrological conditions and their pollution with diverse chemical compounds.
 There are a lot of approaches to ecological water quality assessment according to both abiotic (physical and chemical) and biological parameters. Physical and chemical methods take into account such parameters as water transparency, suspended particulate matter concentration (turbidity), ion composition, water hardness, total dissolved salts content, nutrients and organic matter content, dissolved gases concentration, pH. Biological methods are based upon assessing the living organisms’ (biological indicators’) response to mineral and organic substances, present in water. Various living organisms can be used as biological indicators: algae, in particular – diatoms, higher aquatic plants, different species of aquatic invertebrates and fishes. While physical and chemical methods characterize water quality at the moment of sampling, biological methods provide an integral picture of water quality for a certain time period. Besides, biological methods are more informative, because they reflect the aquatic ecosystem’s response to pollution.
 On the whole, the most reliable data on ecological water quality can be obtained by combining physical, chemical and biological methods.

Strong variations and shifting mechanisms of altitudal diversity and abundance patterns in soil oribatid mites (Acari: Oribatida) on the Changbai Mountain, China

Biological composition and structure vary strongly with elevation, however, the vertical distribution of soil fauna and its drivers have been rarely investigated. Oribatid mites play an essential role in soil faunal composition, where they can occur at high densities and mediate soil ecological processes and functions. Here, we comprehensively investigated the composition and diversity of soil oribatid mites, at nine altitudes (from 600 to 2200 m asl) and four vegetation types from forest to alpine tundra on the Changbai Mountain in July 2021. In total, 67 species were identified among 37,224 oribatid mite individuals. Oribatid mite species varied strongly with altitude and vegetation type, and only a few species overlapped between elevations. Species abundance and diversity declined significantly as altitude increased, while abundance exhibited a hump-shaped distribution along an elevational gradient, peaking at 1200 m. Beta diversity decomposition analyses revealed that species replacement processes dominated community compositional differences across all study sites (both between vegetation types and elevations). Meanwhile, soil oribatid mite community composition is greatly affected by elevation and vegetation type. Specifically, oribatid mite community varies with elevation across vegetation types. Twelve and twenty indicator species were found at different elevations and vegetation types, respectively. Our study shows that soil moisture content, total phosphorus, available phosphorus, ammonium nitrogen, and nitrate nitrogen are the most dominant drivers of oribatid mite composition patterns. These findings indicate oribatid mite assemblages have a distinct vertical distribution pattern and are coupled with different aboveground vegetation types, implying that changes in aboveground vegetation will cause shifts in soil fauna under future climate change.