Study of the Effects of Remote Heavy Group Vibrations on the Temperature Dependence of Hydride Kinetic Isotope Effects of the NADH/NAD+ Model Reactions.

It has recently been observed that the temperature(T)-dependence of KIEs in H-tunneling reactions, characterized by isotopic activation energy difference (ΔEa = EaD - EaH), is correlated to the rigidity of the tunneling ready states (TRSs) in enzymes. A more rigid system with narrowly distributed H-donor-acceptor distances (DADs) at the TRSs gives rise to a weaker T-dependence of KIEs (i.e., a smaller ΔEa). Theoreticians have attempted to develop new H-tunneling models to explain this, but none has been universally accepted. In order to further understand the observations in enzymes and provide useful data to build new theoretical models, we have studied the electronic and solvent effects on ΔEa's for the hydride-tunneling reactions of NADH/NAD+ analogues. We found that a tighter charge-transfer (CT) complex system gives rises to a smaller ΔEa, consistent with the enzyme observations. In this paper, we use the remote heavy group (R) vibrational effects to mediate the system rigidity to study the rigidity-ΔEa relationship. The specific hypothesis is that slower vibrations of a heavier remote group would broaden the DAD distributions and increase the ΔEa value. Four NADH/NAD+ systems were studied in acetonitrile but most of such heavy group vibrations do not appear to significantly increase the ΔEa. The remote heavy group vibrations in these systems may have not affected the CT complexation rigidity to a degree that can significantly increase the DADs, and further, the ΔEa values.

Study on the Environmental Impact and Benefits of Incorporating Humus Composites in Anaerobic Co-Digestion Treatment.

This study evaluated the environmental impact and overall benefits of incorporating humus composites in the anaerobic co-digestion of kitchen waste and residual sludge. The life cycle assessment method was used to quantitatively analyze the environmental impact of the entire anaerobic co-digestion treatment process of waste, including garbage collection, transportation, and final product utilization. Moreover, the comprehensive assessment of the environmental impact, energy-saving and emission-reduction abilities, and economic cost of using humus composites in the anaerobic co-digestion treatment process was conducted using a benefit analysis method. The results showed that the anaerobic co-digestion of kitchen waste and residual sludge significantly contributed to the mitigation of global warming potential (GWP), reaching -19.76 kgCO2-eq, but had the least impact on the mitigation of acidification potential (AP), reaching -0.10 kgSO2-eq. In addition, the addition of humus composites significantly increased the production of biogas. At a concentration of 5 g/L, the biogas yield of the anaerobic co-digestion process was 70.76 m3, which increased by 50.62% compared with the blank group. This amount of biogas replaces ~50.52 kg of standard coal, reducing CO2 emissions by 13.74 kg compared with burning the same amount of standard coal. Therefore, the anaerobic co-digestion treatment of kitchen waste and residual sludge brings considerable environmental benefits.

Distribution, seasonal variation and ecological risk assessment of phthalates in the Yitong River, a typical urban watercourse located in Northeast China.

Phthalates (PAEs) are a typical class of endocrine disruptors (EEDs). As one of the most commonly used plasticizers, they have received widespread attention due to their wide application in various countries and high detection rates in various environmental media. To be able to clarify the contamination status of PAEs pollutants in a typical northern cold-temperate urban river, 30 water samples from Yitong River in Changchun City, northern China were collected, during the 2023 dry season (March), normal season (May) and wet season (July). Using these samples, a total of 16 target PAEs are investigated. The resulting total PAEs concentrations are: dry season 408 to 1494 ng/L, wet season 491 to 1299 ng/L, and normal season 341 to 780 ng/L. The average concentration of the 16 PAEs over the three seasons is 773 ng/L. Di-2-ethylhexyl phthalate (DEHP) and Dibutyl phthalate (DBP) have the highest concentrations, ranging from 12 to 403 ng/L and 28-680 ng/L respectively. The ecological risks within the Yitong River Basin are evaluated based on the degree of PAEs contamination. DBP and DEHP pose higher risk assessment levels for algae, crustaceans and fish than the other target PAEs. The accurate determination of PAEs provided baseline data on PAEs for the management of the Yitong River, which is of great significance for the prediction of ecological risk assessment and the development of corresponding control measures, supported further research on PAEs in the cold-temperate zone aquatic environments, and shed light on the seasonal variations of PAEs in the Northeast region in the future. Moreover, considering the bioaccumulation and persistence of PAEs, it is necessary to continue to pay attention to the pollution status of cold-temperate zones rivers and the changes in ecological risks in the future.

The influence of tag sequence on recombinant humanized collagen (rhCol) and the evaluation of rhCol on Schwann cell behaviors.

Recombinant humanized collagen (rhCol) was an extracellular matrix (ECM)-inspired biomimetic biomaterial prepared by biosynthesis technology, which was considered non-allergenic and could possibly activate tissue regeneration. The influence of tag sequence on both structures and performances of rhCol type III (rhCol III) was investigated, and the effect of rhCol III on cell behaviors was evaluated and discussed using Schwann cells (SCs) as in vitro model that was critical in the repair process after peripheral nerve injury. The results demonstrated that the introduction of tag sequence would influence both advanced structures and properties of rhCol III, while rhCol III regulated SCs adhesion, spreading, migration and proliferation. Also, both nerve growth factor and brain-derived neurotrophic factor increased when exposed to rhCol III. As the downstream proteins of integrin-mediated cell adhesions, phosphorylation of focal adhesion kinase and expression of vinculin was up-regulated along with the promotion of SCs adhesion and migration. The current findings contributed to a better knowledge of the interactions between rhCol III and SCs, and further offered a theoretical and experimental foundation for the development of rhCol III-based medical devices and clinical management of peripheral nerve injury.

Correlation of temperature dependence of hydride kinetic isotope effects with donor-acceptor distances in two solvents of different polarities.

Recently observed nearly temperature (T)-independent kinetic isotope effects (KIEs) in wild-type enzymes and T-dependent KIEs in variants were used to suggest that H-tunneling in enzymes is assisted by the fast protein vibrations that help sample short donor-acceptor distances (DADs). This supports the recently proposed role of protein vibrations in DAD sampling catalysis. However, use of T-dependence of KIEs to suggest DAD sampling associated with protein vibrations is debated. We have formulated a hypothesis regarding the correlation and designed experiments in solution to investigate it. The hypothesis is, a more rigid system with shorter DADTRS's at the tunneling ready states (TRSs) gives rise to a weaker T-dependence of KIEs, i.e., a smaller ΔEa (= EaD - EaH). In a former work, the solvent effects of acetonitrile versus chloroform on the ΔEa of NADH/NAD+ model reactions were determined, and the DADPRC's of the productive reactant complexes (PRCs) were computed to substitute the DADTRS for the DADTRS-ΔEa correlation study. A smaller ΔEa was found in the more polar acetonitrile where the positively charged PRC is better solvated and has a shorter DADPRC, indirectly supporting the hypothesis. In this work, the TRS structures of different DADTRS's for the hydride tunneling reaction from 1,3-dimethyl-2-phenylimidazoline to 10-methylacridinium were computed. The N-CH3/CD3 secondary KIEs on both reactants were calculated and fitted to the observed values to find the DADTRS order in both solutions. It was found that the equilibrium DADTRS is shorter in acetonitrile than in chloroform. Results directly support the DADTRS-ΔEa correlation hypothesis as well as the explanation that links T-dependence of KIEs to DAD sampling catalysis in enzymes.

Alpha-ketoglutarate promotes alveolar bone regeneration by modulating M2 macrophage polarization.

Objectives: Alpha-ketoglutarate (αKG) is an essential metabolite that plays a crucial role in skeletal homeostasis. Here we aim to investigate the effect of αKG on alveolar socket healing and reveal the underlying mechanism in the view of macrophage polarization. Methods: In a murine model pretreated with or without αKG, mandibular first molars were extracted. Mandibular tissues were harvested for microCT and histological analyses. Immunofluorescence was used to evaluate macrophage polarization during healing process. Macrophages with αKG/vehicle supplementation in vitro were proceeded to quantitative real-time PCR and flow cytometry to further elucidate the mechanism. Results: MicroCT and histological analyses showed accelerated healing and enhanced bone regeneration of extraction sockets in experimental group. αKG increased new bone volume in alveolar sockets and promoted the activity of both osteoblastogenesis and osteoclastogenesis. αKG administration reduced M1 pro-inflammatory macrophages in an early phase and promoted anti-inflammatory M2 macrophage polarization in a later phase. Consistently, the expressions of M2 marker genes were augmented in αKG group, while M1 marker genes were downregulated. Flow cytometry revealed the increased ratio of M2/M1 macrophages in cells treated with αKG. Conclusions: αKG accelerates the healing process of extraction sockets via orchestrating macrophage activation, with promising therapeutic potential in oral clinics.

Recombination humanized type III collagen promotes oral ulcer healing.

OBJECTIVE: Recombinant humanized type III collagen (rhCol III) is a highly adhesive biomaterial composed of 16 adhesion-related tandem repeats refined from human type III collagen. Here, we aimed to investigate the effect of rhCol III on oral ulcers and reveal the underlying mechanism. METHODS: Acid-induced oral ulcers were induced on the murine tongue, and rhCol III or saline drops were administered. The effect of rhCol III on oral ulcers was assessed using gross and histological analyses. The effects on the proliferation, migration, and adhesion of human oral keratinocytes were investigated in vitro. The underlying mechanism was explored using RNA sequencing. RESULTS: Administration of rhCol III accelerated the lesion closure of oral ulcers, reduced the release of inflammatory factors, and alleviated pain. rhCol III promoted the proliferation, migration, and adhesion of human oral keratinocytes in vitro. Mechanistically, the enrichment of genes associated with the Notch signaling pathway was upregulated after rhCol III treatment. CONCLUSION: rhCol III promoted the healing of oral ulcers, showing promising therapeutic potential in oral clinics.

Solvent Effects on the Temperature Dependence of Hydride Kinetic Isotope Effects: Correlation to the Donor-Acceptor Distances.

Protein structural effects on the temperature (T) dependence of kinetic isotope effects (KIEs) in H-tunneling reactions have recently been used to discuss about the role of enzyme thermal motions in catalysis. Frequently observed nearly T-independent KIEs in the wild-type enzymes and T-dependent KIEs in variants suggest that H-tunneling in the former is assisted by the naturally evolved protein constructive vibrations that help sample short donor-acceptor distances (DADs) needed. This explanation that correlates the T-dependence of KIEs with DAD sampling has been highly debated as simulations following other H-tunneling models sometimes gave alternative explanations. In this paper, solvent effects on the T-dependence of KIEs of two hydride tunneling reactions of NADH/NAD+ analogues (represented by ΔEa = EaD - EaH) were determined in attempts to replicate the observations in enzymes and test the protein vibration-assisted DAD sampling concept. Effects of selected aprotic solvents on the DADPRC's of the productive reactant complexes (PRCs) and the DADTRS's of the activated tunneling ready states (TRSs) were obtained through computations and analyses of the kinetic data, including 2° KIEs, respectively. A weaker T-dependence of KIEs (i.e., smaller ΔEa) was found in a more polar aprotic solvent in which the system has a shorter average DADPRC and DADTRS. Further results show that a charge-transfer (CT) complexation made of a stronger donor/acceptor gives rise to a smaller ΔEa. Overall, the shorter and less broadly distributed DADs resulting from the stronger CT complexation vibrations give rise to a smaller ΔEa. Our results appear to support the explanation that links the T-dependence of KIEs to the donor-acceptor rigidity in enzymes.

Direct Correlation between Donor-Acceptor Distance and Temperature Dependence of Kinetic Isotope Effects in Hydride-Tunneling Reactions of NADH/NAD+ Analogues.

Recent study of structural effects on primary kinetic isotope effects (1° KIEs) of H-transfer reactions in enzymes and solution revealed that a more rigid reaction system gave rise to a weaker temperature dependence of 1° KIEs, i.e., a smaller isotopic activation energy difference (ΔEa = EaD - EaH). This has been explained within the contemporary vibrationally assisted activated H-tunneling (VA-AHT) model in which rigidity is defined according to the density of donor-acceptor distance (DADTRS) populations at the tunneling ready state (TRS) sampled by heavy atom motions. To test the relationship between DADTRS and ΔEa in the model, we developed a computational method to obtain the TRS structures for H-transfer reactions. The method was applied to three hydride transfer reactions of NADH/NAD+ analogues for which the ΔEa's as well as secondary (2°) KIEs have been reported. The 2° KIEs computed from each TRS structure were fitted to the observed values to obtain the optimal TRSs/DADTRS's. It was found that a shorter DADTRS does correspond with a smaller ΔEa. This appears to support the VA-AHT model. Moreover, an analysis of hybridizations at the bent TRS structures shows that rehybridizations at the donor-acceptor centers are much more advanced than predicted from the classical mechanism. This implies that more orbital preparations are required for the nonclassical H-tunneling to take place.

Expression of eosinophil in peripheral blood of patients with COVID-19 and its clinical significance.

AIMS: To investigate the eosinophil cell (EC) expression in peripheral blood of patients infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) and its clinical significance of diagnosis and prognosis. METHODS: 95 patients, whose nucleic acid test of SARS-CoV-2 was positive to make a definite diagnosis of COVID-19, were selected as the study group. They were admitted at the Chengdu Public Health Clinical Medical Center from January 21 to March 2, 2020. Another 95 healthy subjects and 95 non-infectious fever patients during the same period were selected as the control group. The BC-6900 blood cell analyzer was used to continuously observe and detect ECs in 95 patients with COVID-19 and the control group. The differences in expression levels of ECs in peripheral blood were analyzed. RESULTS: ECs were significantly decreased in 95 (75.8%) COVID-19 patients (P < .01). The absolute EC count IQR was 0.01 × 109/L (0 × 109/L - 0.04 × 109/L), and the EC percentage IQR was 0.3% (0.1% - 0.8%). As the patients' condition improved, the ECs returned to normal, but for those without improvement, ECs continued to decline. CONCLUSIONS: ECs decreased remarkably in patients with COVID-19, and gradually returned to normal after the improvement of the patients' condition, while EC continued to decrease in patients without improvement. It is suggested that ECs have certain clinical significance in the diagnosis and prognosis of COVID-19, and may be a useful index in the early warning of acute infectious diseases.

The non-viral vectors and main methods of loading siRNA onto the titanium implants and their application.

Surface modification of titanium implants by siRNA is quite efficient for improving implant osseointegration. Loading siRNA onto their surface is a crucial factor for siRNA-functionalized implants to realize their biological function. Direct binding of siRNA to implants has low siRNA binding and releasing rate, so usually it needs to be mediated by vectors. Polymeric, nonmaterial-mediated and lipid-based vectors are types of non-viral vectors which are commonly used for delivering siRNA. Three major methods of loading process, namely simple physical adsorption, layer-by-layer assembly and electrodeposition, are also summarized. A brief introduction, the basic principle and the general procedure of each method are included. The loading efficiency, which can be measured both qualitatively and quantitatively, together with gene knockdown efficiency, cytotoxicity assay and osteogenesis of the three methods are compared. A good many applications in osteogenesis have also been described in this review.

A Multisensor Data Fusion Method Based on Gaussian Process Model for Precision Measurement of Complex Surfaces.

As multisensor measurement technology is rapidly applied in industrial production, one key issue is the data fusion procedure by combining several datasets from multiple sensors to obtain the overall geometric measurement. In this paper, a multisensor data fusion method based on a Gaussian process model is proposed for complex surface measurements. A robust surface registration method based on the adaptive distance function is firstly used to unify the coordinate systems of different measurement datasets. By introducing an adjustment model, the residuals between several independent datasets from different sensors are then approximated to construct a Gaussian process model-based data fusion system. The proposed method is verified through both simulation verification and actual experiments, indicating that the proposed method can fuse multisensor measurement datasets with better fusion accuracy and faster computational efficiency compared to the existing method.

Stretchable Graphene Thin Film Enabled Yarn Sensors with Tunable Piezoresistivity for Human Motion Monitoring.

1D graphene based flexible sensors as wearable electronics have recently attracted considerable attentions because of lightweight, high extensibility, easy to wind and weave, and superior sensitivity. In this research, we established a facile and low-cost strategy to construct graphene thin film enabled yarn sensors (GYS) by combining the process of graphene oxide (GO) coating and reducing on polyester (PE) wound spandex yarns. According to systematic processing-property relationship study, a key finding of this work discovers that the degree of resistance recovery as well as gauge sensitivity of GYS can be well controlled and modulated by a pre-stretch treatment. Specifically, as the level of pre-stretch increases from 0 to 60%, the deformable range of sensor that guarantees full resistance recovery prolongs evidently from 0% to ~50%. Meanwhile, the gauge factor of GYS is tunable in the range from 6.40 to 12.06. To understand the pre-stretch process dependent sensing performance, SEM analysis was assisted to evidence the growing size of micro-cracks determining dominantly the behavior of electron transport. Lastly, to take better advantage of GYS, a new wearing mode was demonstrated by direct winding the yarn sensor on varied portions of human body for monitoring different body movements and muscle contracting & relaxing.

Replication of the Enzymatic Temperature Dependency of the Primary Hydride Kinetic Isotope Effects in Solution: Caused by the Protein-Controlled Rigidity of the Donor-Acceptor Centers?

The change from the temperature independence of the primary (1°) H/D kinetic isotope effects (KIEs) in wild-type enzyme-catalyzed H-transfer reactions (ΔEa = EaD - EaH ∼ 0) to a strong temperature dependence with the mutated enzymes (ΔEa ≫ 0) has recently been frequently observed. This has prompted some enzymologists to develop new H-tunneling models to correlate ΔEa with the donor-acceptor distance (DAD) at the tunneling-ready state (TRS) as well as the protein thermal motions/dynamics that sample the short DADTRS's for H-tunneling to occur. While extensive evidence supporting or disproving the thermally activated DAD sampling concept has emerged, a comparable study of the simpler bimolecular H-tunneling reactions in solution has not been carried out. In particular, small ΔEa's (∼0) have not been found. In this paper, we report a study of the hydride-transfer reactions from four NADH models to the same hydride acceptor in acetonitrile. The ΔEa's were determined: 0.37 (small), 0.60, 0.99, and 1.53 kcal/mol (large). The α-secondary (2°) KIEs on the acceptor that serve as a ruler for the rigidity of reaction centers were previously reported or determined. All possible productive reactant complex (PRC) configurations were computed to provide insight into the structures of the TRS's. Relationships among structures, 2° KIEs, DADPRC's, and ΔEa's were discussed. The more rigid system with more suppressed 2° C-H vibrations at the TRS and more narrowly distributed DADPRC's in PRCs gave a smaller ΔEa. The results replicated the trend observed in enzymes versus mutated enzymes and appeared to support the concepts of different thermally activated DADTRS sampling processes in response to the rigid versus flexible donor-acceptor centers.