A mineral-based origin of Earth's initial hydrogen peroxide and molecular oxygen.

Terrestrial reactive oxygen species (ROS) may have played a central role in the formation of oxic environments and evolution of early life. The abiotic origin of ROS on the Archean Earth has been heavily studied, and ROS are conventionally thought to have originated from H2O/CO2 dissociation. Here, we report experiments that lead to a mineral-based source of oxygen, rather than water alone. The mechanism involves ROS generation at abraded mineral-water interfaces in various geodynamic processes (e.g., water currents and earthquakes) which are active where free electrons are created via open-shell electrons and point defects, high pressure, water/ice interactions, and combinations of these processes. The experiments reported here show that quartz or silicate minerals may produce reactive oxygen-containing sites (≡SiO•, ≡SiOO•) that initially emerge in cleaving Si-O bonds in silicates and generate ROS during contact with water. Experimental isotope-labeling experiments show that the hydroxylation of the peroxy radical (≡SiOO•) is the predominant pathway for H2O2 generation. This heterogeneous ROS production chemistry allows the transfer of oxygen atoms between water and rocks and alters their isotopic compositions. This process may be pervasive in the natural environment, and mineral-based production of H2O2 and accompanying O2 could occur on Earth and potentially on other terrestrial planets, providing initial oxidants and free oxygen, and be a component in the evolution of life and planetary habitability.

Kinetics of Oriented Attachment of Mica Crystals.

Oriented attachment (OA), that is, the coalescence of crystals through attachment on coaligned crystal faces, is a nonclassical crystal growth process. Before attachment, a mesocrystal consisting of coaligned parallel crystals but with liquid separating them was observed. Fundamental questions such as why OA is kinetically favored and whether a mesocrystal stage is a prerequisite for OA are raised. Through combining brute-force molecular dynamics simulations and path samplings based on extensive umbrella simulations, we address these questions with a case study on the OA of a mica nanocrystal onto a mica crystal substrate in water. Brute-force simulations show that if two mica crystals are attached but largely misaligned, coalignment hardly appears. Thus, if OA is possible, then coalignment must appear before the attachment between crystals. Electrophoresis of the nanocrystal toward the substrate surface is spontaneous, but mesocrystal formation is occasional, also shown by brute-force simulations. Free energies along different pathways show that OA is spontaneous and kinetically favored over non-OA, and a mesocrystal formation is just a bifurcation in the pathway. OA is through a pathway in which the nanocrystal is tilted with respect to the substrate. Part of the nanocrystal is attached to the substrate first, and then, OA is gradually completed. Once a mesocrystal is occasionally formed, then a jump event is needed for the nanocrystal to get back to the OA pathway. The sampling technique here can hopefully guide the design of nanostructured materials facilitated by OA.

Effect of virtual reality training to enhance laparoscopic assistance skills.

BACKGROUND: While laparoscopic assistance is often entrusted to less experienced individuals, such as residents, medical students, and operating room nurses, it is important to note that they typically receive little to no formal laparoscopic training. This deficiency can lead to poor visibility during minimally invasive surgery, thus increasing the risk of errors. Moreover, operating room nurses and medical students are currently not included as key users in structured laparoscopic training programs. OBJECTIVES: The aim of this study is to evaluate the laparoscopic skills of OR nurses, clinical medical postgraduate students, and residents before and after undergoing virtual reality training. Additionally, it aimed to compare the differences in the laparoscopic skills among different groups (OR nurses/Students/Residents) both before and after virtual reality training. METHODS: Operating room nurses, clinical medical postgraduate students and residents from a tertiary Grade A hospital in China in March 2022 were selected as participants. All participants were required to complete a laparoscopic simulation training course in 6 consecutive weeks. One task from each of the four training modules was selected as an evaluation indicator. A before-and-after self-control study was used to compare the basic laparoscopic skills of participants, and laparoscopic skill competency was compared between the groups of operating room nurses, clinical medical postgraduate students, and residents. RESULTS: Twenty-seven operating room nurses, 31 clinical medical postgraduate students, and 16 residents were included. The training course scores for the navigation training module, task training module, coordination training module, and surgical skills training module between different groups (operating room nurses/clinical medical postgraduate/residents) before laparoscopic simulation training was statistically significant (p < 0.05). After laparoscopic simulation training, there was no statistically significant difference in the training course scores between the different groups. The surgical level scores before and after the training course were compared between the operating room nurses, clinical medical postgraduate students, and residents and showed significant increases (p < 0.05). CONCLUSION: Our findings show a significant improvement in laparoscopic skills following virtual surgery simulation training across all participant groups. The integration of virtual surgery simulation technology in surgical training holds promise for bridging the gap in laparoscopic skill development among health care professionals.

Early Identification of Rotten Potatoes Using an Electronic Nose Based on Feature Discretization and Ensemble Convolutional Neural Network.

The early identification of rotten potatoes is one of the most important challenges in a storage facility because of the inconspicuous symptoms of rot, the high density of storage, and environmental factors (such as temperature, humidity, and ambient gases). An electronic nose system based on an ensemble convolutional neural network (ECNN, a powerful feature extraction method) was developed to detect potatoes with different degrees of rot. Three types of potatoes were detected: normal samples, slightly rotten samples, and totally rotten samples. A feature discretization method was proposed to optimize the impact of ambient gases on electronic nose signals by eliminating redundant information from the features. The ECNN based on original features presented good results for the prediction of rotten potatoes in both laboratory and storage environments, and the accuracy of the prediction results was 94.70% and 90.76%, respectively. Moreover, the application of the feature discretization method significantly improved the prediction results, and the accuracy of prediction results improved by 1.59% and 3.73%, respectively. Above all, the electronic nose system performed well in the identification of three types of potatoes by using the ECNN, and the proposed feature discretization method was helpful in reducing the interference of ambient gases.

Histone mRNA polyadenylation-mediated inflammation underlies various virus infections and cancers.

The mechanistic understanding of virus infection and inflammation in many diseases is incomplete. Normally, messenger RNA (mRNA) tails of replication-dependent histones (RDH) that safeguard naked nuclear DNAs are protected by a specialized stem-loop instead of polyadenylation. Here, we showed that infection by various RNA viruses (including severe acute respiratory syndrome coronavirus 2) induced aberrant polyadenylation of RDH mRNAs (pARDH) that resulted in inflammation or cellular senescence, based on which we constructed a pARDH inflammation score (pARIS). We further investigated pARIS elevation in various disease conditions, including different types of virus infection, cancer, and cellular senescence. Notably, we found that pARIS was positively correlated with coronavirus disease 2019 severity in specific immune cell types. We also detected a subset of HIV-1 elite controllers characterized by pARDH "flipping" potentially mediated by HuR. Importantly, pARIS was positively associated with transcription of endogenous retrovirus but negatively associated with most immune cell infiltration in tumors of various cancer types. Finally, we identified and experimentally verified two pARIS regulators, ADAR1 and ZKSCAN1, which was first linked to inflammation. The ZKSCAN1 was known as a transcription factor but instead was shown to regulate pARIS as a novel RNA binding protein. Both regulators were upregulated under most infection and inflammation conditions. In conclusion, we unraveled a potential antiviral mechanism underlying various types of virus infections and cancers.

Microorganisms Accelerate REE Mineralization in Supergene Environments.

Exogenic deposits are an important source of rare earth elements (REEs), especially heavy REEs (HREEs). It is generally accepted that microorganisms are able to dissolve minerals and mobilize elements in supergene environments. However, little is known about the roles of microorganisms in the formation of exogenic deposits such as regolith-hosted REE deposits that are of HREE enrichment and provide over 90% of global HREE demand. In this study, we characterized the microbial community composition and diversity along a complete weathering profile drilled from a regolith-hosted REE deposit in Southeastern China and report the striking contributions of microorganisms to the enrichment of REEs and fractionation between HREEs and light REEs (LREEs). Our results provide evidence that the variations in REE contents are correlated with microbial community along the profile. Both fungi and bacteria contributed to the accumulation of REEs, whereas bacteria played a key role in the fractionation between HREEs and LREEs. Taking advantage of bacteria strains isolated from the profile, Gram-positive bacteria affiliated with Bacillus and Micrococcus preferentially adsorbed HREEs, and teichoic acids in the cell wall served as the main sites for HREE adsorption, leading to an enrichment of HREEs in the deposit. The present study provides the first database of microbial community in regolith-hosted REE deposits. These findings not only elucidate the crucial contribution of fungi and bacteria in the supergene REE mineralization but also provide insights into efficient utilization of mineral resources via a biological pathway. IMPORTANCE Understanding the role of microorganisms in the formation of regolith-hosted rare earth element (REE) deposits is beneficial for improving the metallogenic theory and deposit exploitation, given that such deposits absolutely exist in subtropical regions with strong microbial activities. Little is known of the microbial community composition and its contribution to REE mineralization in this kind of deposit. Using a combination of high-throughput sequencing, batch adsorption experiments, and spectroscopic characterization, the functional microorganisms contributing to REE enrichment and fractionation are disclosed. For bacteria, the surface carboxyl and phosphate groups are active sites for REE adsorption, while teichoic acids in the cell walls of G+ bacteria lead to REE fractionation. The above-mentioned findings not only unravel the importance of microorganisms in the formation of supergene REE deposits but also provide experimental evidence for the bioutilization of REE resources.

Assessing environmental fate of hexavalent chromium as influenced by fractionation of ferrihydrite with dissolved organic matter.

The dynamic interactions among iron (Fe) oxides, dissolved organic matter (DOM) and toxic trace metals play crucial roles in risk assessment and environmental remediation. Although the inhibitory effects of DOM on the iron oxides transformation process have been studied previously, there is still a lack of mechanistic and quantitative understanding on the kinetics of Cr(VI) and ferrihydrite transformation in the present of DOM. In this study, we investigated the fractionation process of DOM on ferrihydrite and its influence on the fate of Cr(VI) and transformation of ferrihydrite. The result of three-dimension excitation emission matrix (3D-EEM), Q-Exactive LC-MS/MS, X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) indicated that fulvic acid-like compounds of DOM were the mainly fractionated compounds on the surface of ferrihydrite, which further inhibited the transformation of ferrihydrite. Besides, bracewellite (CrO(OH)) generated as an accompanied mineral during the transformation of ferrihydrite in the present of Cr(VI). Based on the DFT theoretical calculation, we concluded that Cr(VI) mainly in the form of HCr O4- was more inclined to be adsorbed on iron-oxide tetrahedron by inner-sphere monodentate mononuclear configurations. The findings on the dynamic coupling among Fe oxide transformation and Cr(VI) sequestration under the effect of DOM provided the basis for accurately predicting the fate of trace elements and iron mineral.

Intrinsic water layering next to soft, solid, hydrophobic, and hydrophilic substrates.

How a substrate modulates properties of water upon it and how far the perturbation is present remain to be fundamental questions in surface science. To answer these questions, we develop a layer-by-layer exfoliation method to identify physically meaningful water layers upon a substrate through molecular dynamics simulations under ambient conditions. The results show a qualitatively consistent long-ranged layer-by-layer propagation of the atomic structure, irrespective of whether the substrate is soft, solid, hydrophobic, or hydrophilic. The capillary-wave fluctuation of a water layer upon air or oil diverges with long wavelength but is truncated upon solid substrates by an effective field, which exhibits a long-ranged decay but its strength is almost irrelevant with substrate chemistry. The distinction in the water structure and atomic dynamics due to substrate specificity is mostly limited to the outmost layer. We conclude a long-ranged layering organization and a short-ranged substrate-dependent specificity for interfacial water.

The catalytic process of poly-silicate-ferric (PSF) and generation mechanism of hydroxyl radical based on photo-Fenton system.

Poly-silicate-ferric (PSF) was developed as an heterogeneous UV-Fenton catalyst, which was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), UV-vis diffuse reflectance spectroscopy (DRS), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). The catalytic process of PSF and generation mechanism of hydroxyl radical based on photo-Fenton system were studied in detail. In the heterogeneous UV-Fenton system, the kapp value of Orange II degradation was as high as 0.268 min-1, which was 1.5 times compared to that with α-FeOOH as catalyst. As a result, the Orange II decolouration and mineralization rates were as high as 99.9% and 92.5% after 40 min treatment, respectively. Moreover, the hydroxyl radical concentration would increase to a peak value of 13.4 µmol/L at about 15 min. The fundamental cause of the high hydroxyl radical generation lay in the high release ability of iron ions from PSF. The peak concentrations of total iron ions and ferrous ions could increase to 4.53 mg/L and 1.57 mg/L at 20 min and 10 min, respectively. After treatment, the re-adsorption of iron ions on the surface of PSF could avoid the additional pollution caused by iron ions. The results confirmed that PSF was a high activity catalyst for an heterogeneous UV-Fenton system.

Arrangement Models of Keggin-Al30 and Keggin-Al13 in the Interlayer of Montmorillonite and the Impacts of Pillaring on Surface Acidity: A Comparative Study on Catalytic Oxidation of Toluene.

Acid-base reactivity is a key factor for understanding the interfacial geochemistry of clay minerals. Numerous studies showed the significant role of surface acidity of clay minerals in the geological processes and environmentally related applications. In this work, montmorillonite (Mt) was pillared by polycations of Keggin-Al13 and Keggin-Al30. Arrangement models of Keggin-Al13 and Keggin-Al30 in the interlayer region of Mt were put forward based on the chemical composition analysis, the structural formula calculation of Mt, and the results of powder X-ray diffraction. Ammonia temperature-programmed desorption and diffuse reflectance Fourier transform infrared methods were applied to explore the impacts of pillaring by polycations (Keggin-Al13 and Keggin-Al30) on the surface acidic characteristics of Mt. Results demonstrated that one Keggin-Al30 polycation can affect an area of 9.5 unit cells (from two layers, with 4.7-4.8 unit cells in each layer) in Mt, whereas a Keggin-Al13 polycation controls an area of 7.1 unit cells (from two layers, with 3.5-3.6 unit cells in each layer). Pillaring by polycations could lead to a lot of surface acid sites (1.33 mmol NH3/g) on Mt with the main type of Bronsted acid sites. The increase of surface acid sites on both Keggin-Al13-pillared Mt (Al13-PILM) and Keggin-Al30-pillared Mt (Al30-PILM) is attributed to the high positive charge and high content of aluminum per unit of polycation, which affects the formation of Bronsted acid sites and structural changes of Mt layers. Catalytic oxidation of toluene provided evidence for the high catalytic activity of Al30-PILM under much lower temperature at 78 °C compared with that of Al13-PILM and Mt at 207 and 285 °C, respectively. The basic finding in this study not only reveals the possible sources of abundant micropores and mesopores in the micro/mesoporous materials of Al13-PILM and Al30-PILM but also provides a reasonable mechanism for the formation of abundant Bronsted surface acid sites on these two types of pillared materials. The novel Al30-PILM with an excellent micro/mesoporous structure and extremely high thermal stability also exhibits a potential ability in the application of heterogeneous acid catalysis.