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The effects of nitrogen sources on the biosynthesis of jarosite were investigated by analyzing the changes in pH, Fe2+, total Fe (TFe), and jarosite production in a 9K culture medium containing different nitrogen sources. Three nitrogen sources, namely (NH4)2SO4, carbamide (CO(NH2)2), and NH4NO3, were used in this study. The solution's pH and Fe2+ concentrations were set to 2.5 and 160 mmol/L, respectively. The results demonstrated that the three different nitrogen sources could be used by Acidithiobacillus ferrooxidans (A. ferrooxidans) LX5, but the degree of utilization differed. The addition of (NH4)2SO4 facilitated the growth of A. ferrooxidans LX5 compared with the other two nitrogen sources, while the bacterial activity in the CO(NH2)2 set was minimum. The pH of the solution had an inverse correlation with bacterial activity. The mineralization rate using (NH4)2SO4 as the nitrogen source was 42.48%, which was slightly higher than the rates obtained with CO(NH2)2 and NH4NO3 (31.67% and 35.35%, respectively). The resulting minerals showed a different appearance and chemical composition. However, the XRD spectra showed similar chemical structure. The jarosites were identified as a mixture of jarosite, ammonioiarosite, and carphosiderite. [ABSTRACT FROM AUTHOR]

Antlers are paired deciduous bony cranial appendages of deer that undergo a regular cycle of growth, death and casting, and constitute the most rapidly growing bones in mammals. Antler growth occurs in an appositional mode and involves a modified form of endochondral ossification. In endochondral bones, calcified cartilage is typically a transient tissue that is eventually completely replaced by bone tissue. We studied the distribution and characteristics of calcified cartilage in hard antlers from three deer species (Capreolus capreolus, Cervus elaphus, Dama dama), i.e., in antlers from which the skin (velvet) had been shed. Remnants of calcified cartilage were regularly present as part of the trabecular framework in the late formed, distal antler portions in all three species, whereas this tissue was largely or completely missing in the more proximal antler portions. The presence of calcified cartilage remnants in the distal antler portions is attributed to the limited antler lifespan of only a few months, which is also the reason for the virtual lack of bone remodeling in antlers. The calcified cartilage matrix was more highly mineralized than the antler bone matrix. Mineralized deposits were observed in some chondrocyte lacunae and occasionally also in osteocyte lacunae, a phenomenon that has not previously been reported in antlers. Using synchrotron radiation-induced X-ray fluorescence (SR-XRF) mapping, we further demonstrated increased zinc concentrations in cement lines, along the inner borders of incompletely formed primary osteons, along the walls of partly or completely mineral-occluded chondrocyte and osteocyte lacunae, and in intralacunar mineralized deposits. The present study demonstrates that antlers are a promising model for studying the mineralization of cartilage and bone matrices and the formation of mineralized deposits in chondrocyte and osteocyte lacunae.

Observations in crystal growth and assembly from recent in situ methods suggest alternative, non-classical crystallization pathways play an important role in the determination of the micro- and meso- structures in crystalline systems. These processes display parallels that cross-cut multiple disciplines investigating crystallization across four orders of magnitude in size scales and widely differing environments, hinting that alternative crystal growth pathways may be a fundamental scheme in natural crystal formation. Using a system of short-range attractive microbeads, we demonstrate that the addition of a small concentration of sub-species incommensurate with the lattice spacing of the dominant species results in a stark change in crystal size and morphology. These changes are attributed to the presence of fleeting, amorphous-like configurations of beads that ultimately change the melting and growth dynamics in preferred directions. From these real-time observations, we hypothesize the amorphous mineral precursors present in biological mineralized tissues undergo similar non-classical crystallization processes resulting in the complex structures found in biomineralization.

Fertilization is a crucial agrological measure for agricultural production that can significantly impact the removal of Cd from irrigation water by paddy crusts (PC). In this study, laboratory and field experiments were conducted to investigate the impact of fertilization at low, medium, and high concentrations on the accumulation of Cadmium (Cd) in PC and the underlying mechanisms involved. The results showed that only low fertilizer concentration could promote the removal of Cd by PC, which reduced the Cd concentration in irrigation water from 19.52 μg/L to 5.35 μg/L. Conversely, medium and high fertilizer concentrations reduced the accumulation of Cd by PC. After fertilizer addition, the proportion of Fe-Mn oxidizable-Cd in PC reached 55 % (with low concentration of fertilizer treatment). The application of low concentration of fertilizer was found to stimulate the growth of filamentous green algae, leading to a significant increase in the relative abundance of sphingomonadaceae (by 1.39 %) and comamonadaceae (by 1.29 %). The XRD, SEM and correlation analysis show that a large amount of manganese oxide is formed on the surface of PC, which increases the fixation of Cd. These findings provide a new perspective for the remediation of heavy metal contamination in paddy fields. [Display omitted] • The low concentration fertilizer promoted the removal of Cd from irrigation water by paddy crust (PC). • The fractionation of Cd in PC is dominated by Fe-Mn oxidation state. • Fertilizer increased the abundance of sphingomonadaceae and comamonadaceae in PC. • The application of low concentration fertilizer reduced the content of Cd in rice. [ABSTRACT FROM AUTHOR]

Some contemporary methods and materials are available in geotechnical engineering to improve the engineering performance of soils. Bacterial calcium carbonate cementation could be an innovative application by bonding at the particle contacts and increasing the shear strength. Bacteria type is the most effective factor on the calcium carbonate precipitation while incubation time, concentration, and pH were minor effects. The increasing urea concentration reduces the amorphous phase and increases the crystalline phase with vaterite. Meanwhile, the increasing incubation time is very effective transforming the vaterite crystals to calcite. Paenibacillus favisporus U3 forms the maximum calcium carbonate precipitation among the tested ones, and it is utilized for the geotechnical studies. The unit weights of the samples are not changed noticeably by the bacterial procedure. The uniaxial compressive strength of the tested core samples are varying in a quite large range from 66.8 to 204.1 kPa. The young modulus of the treated samples reaches up to 89.4 MPa. The Vp and Vs sonic velocity values rise up to 985 and 443 m/s, respectively. The images prove the homogeneous distribution of bacterial carbonate cement material among the soil grains, and it fills the gaps up to 0.5 mm size. The improvement provided by the bacterial treatment is sufficient to support the project loads in very large areas like transportation projects and factory sites. The method can be employed in the associated geotechnical engineering applications. [ABSTRACT FROM AUTHOR]

Desired orthopedic implant materials must have a good biological activity and possess appropriate mechanical property that correspond to those of human bone. Although polyetheretherketone (PEEK) has displayed a promising application prospect in musculoskeletal and dentistry reconstruction thanks to its non-biodegradability and good biocompatibility in the body, the poor osseointegration and insufficient mechanical strength have significantly limited its application in the repair of load-bearing bones and surgical operations. In this study, carbon nanotubes (CNT)/calcium silicate (CS)/polyetheretherketone ternary composites were fabricated for the first time. The addition of CS was mainly aimed at improving biological activities and surface hydrophilicity, but it inevitably compromised the mechanical strength of PEEK. CNT can reinforce the composites even when brittle CS was introduced and further upgraded the biocompatibility of PEEK. The CNT/CS/PEEK composites exhibited higher mechanical strengths in tensile and bending tests, 64% and 90% higher than those of brittle CS/PEEK binary composites. Besides, after incorporation of CNT and CS into PEEK, the hydrophilicity, surface roughness and ability to induce apatite-layer deposition were significantly enhanced. More importantly, the adhesion, proliferation, and osteogenic differentiation of mouse embryo osteoblasts were effectively promoted on CNT/CS/PEEK composites. In contrast to PEEK, these composites exhibited a more satisfactory biocompatibility and osteoinductive activity. Overall, these results demonstrate that ternary CNT/CS/PEEK composites have the potential to serve as a feasible substitute to conventional metal alloys in musculoskeletal regeneration and orthopedic implantation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Cao, Yang, Liao, Wang, He, Xiong, Shi and Hu.)

Background and aims: Deficiencies of S in agricultural crops are becoming more common but comparatively little is known regarding the kinetics of cultivation-induced long-term changes in soil S pools. Methods: In the present study, six soils were examined with samples collected from 82 sites - this allowing examination of the effects of cultivation for up to 70 years. Results: For four of the six soils, long-term cultivation resulted in significant decreases in total S concentrations, with calculated decreases ranging from 35 to 51 %. This decrease was due to mineralization of organic S, with half-life values ranging from 1.0 to 11 years. Generally, organic S decreased linearly with organic C concentrations. For newly-cultivated soils, the mineralization of organic S was sufficient to replace the S harvested in wheat ( Triticum aestivum) grain, but after prolonged cultivation, the rate of S mineralization decreased by several orders of magnitude. Conclusions: The data presented here provide important information on the effects of cultivation on S dynamics within sub-tropical soils - this being required to effectively and sustainably manage these systems. [ABSTRACT FROM AUTHOR]

The effect of biomass density, effect of different ratios of trichloroethylene (TCE) and toluene on biomass, and strategies to cope with problems using acclimated Burkholderia cepacia G4 were investigated. Complete degradation of TCE was achieved when B. cepacia G4 was exposed to 0.5 mg/L TCE and 10 mg/L toluene after starvation of 100 h. Overall results of this study show that degradation rates of toluene decreased as TCE concentration increased. On the contrary, degradation rates of TCE increased up to 10 mg/L TCE and then decreased. Transformation capacity of B. cepacia G4 increased as toluene concentration increased but transformation yield decreased showing that excessive substrate supply may not help to improve specific performance parameters. Results of these experiments bear that instead of simultaneous injection of TCE and substrate, the supply of substrate in pulses can increase the efficiency of B. cepacia G4 or similar bacterial strains. [ABSTRACT FROM AUTHOR]

Abstract: The xenobiotic organic compounds linear alkylbenzene sulfonates (LAS) are among the most thoroughly investigated with respect to biodegradability. Previous studies have shown that LAS are relatively rapidly degraded under aerobic conditions, but only very slowly or not at all degraded under anaerobic conditions. In the present work, the degree of primary and ultimate biodegradation of LAS by consortia of aerobic microorganisms was examined. The quantification of primary biodegradation was conducted via analysis of the LAS content inthe mixed liquor, which was based on microwave-assisted-extraction (MAE) followed by solid phase extraction with liquid chromatography coupled with a fluorescence detector (HPLC-FD). The ultimate biodegradability of LAS was examined by measuring both the disappearance of the test compound and the formation of carbon dioxide using the OECD method 301B or the sulphate. It was found that the established enriched mixed microbial population was capable for complete mineralization of all LAS, as verified by the sulfate production as well as the application of the OECD method and the carbon mass balances carried out throughout the course of the conducted experiments. In particular, any intermediate compound formed during LAS biodegradation was rapidly decomposed, making any intermediate accumulation temporal. [Copyright &y& Elsevier]

The objective of this investigation was to measure phosphorus (P) levels in the epiphyseal growth cartilage and to relate pool sizes to chondrocyte maturation and tissue mineralization. To carry out these studies, we utilized a morphochemical technique that permitted measurements of insoluble mineral phosphate, soluble inorganic phosphate (Pi), low and high molecular weight phosphorylated macromolecules and lipid P in freeze-trapped histological sections. Analysis of the sections revealed that very low levels of P are present in pre-mineralized cartilage; at the mineralization front, a large increase in Pi is correlated with mineral formation. Moreover, with calcification of the cartilage, a decrease in the concentration of low molecular weight compounds was observed. It is suggested that these latter components may provide the initial source of Pi for the development of mineral. The results of the study support the view that metabolic regulation of P pool size may be a rate-limiting factor in the mineralization of cartilage. [ABSTRACT FROM AUTHOR]

Silver nanoclusters (AgNCs) were first coated with bovine serum albumin (BSA) and then encapsulated into porous metal-organic frameworks of ZIF-8 by the protein-mediated biomineralization process. Unexpectedly, the fluorescence intensities of the yielded AgNCs-BSA@ZIF-8 nanocomposites were discovered to be continuously enhanced during each of the BSA coating and ZIF-8 encapsulation steps. Compared to common AgNCs, greatly improved photostability and storage stability of AgNCs could also be expected. More importantly, having benefited from the ZIF-8 shells, the prepared nanocomposites could possess the specific accumulation and sensitive response to Cu 2+ ions, resulting in the rational quenching of their fluorescence intensities. Moreover, AgNCs-BSA@ZIF-8 nanocomposites were coated onto the hydrophobic arraying slides toward a microdots array-based fluorimetric method for the fast and sensitive evaluation of Cu 2+ ions. It was discovered that the developed fluorimetric strategy could ensure the high-throughput analysis of Cu 2+ ions in wide pH range, and especially some harsh and high-salt media. It can allow for the detection of Cu 2+ ions in blood with the concentrations ranging from 4.0 × 10 -4 to 160 μM, thus serving as a new copper detection candidate to be widely applied in clinical test, food safety, and environmental monitoring fields.