Clinical analysis of the effect of helicobacter pylori infection on immune function in children with peptic ulcer.

Objective: To study whether children with peptic ulcer would have abnormalities in cellular and humoral immune functions, and whether Helicobacter pylori (Hp) infection would affect the immune function of children with peptic ulcer. Methods: This is a retrospective study. The subjects of study were 72 children with diagnosed and cured peptic ulcer (ulcer group), and 50 healthy children with physical examination (control group) at Baoding Hospital, Beijing Children's Hospital Affiliated to Capital Medical University from June 2020 to December 2022. Further detection was conducted on T lymphocyte subsets (CD3+, CD4+, CD8+, and CD4+/CD8+ ratio) and immunoglobulin levels. Results: Of the 72 children with peptic ulcer, 53(73.6%) were positive for Hp (Hp-positive group) and 19 (26.4%) were negative (Hp-negative group). The levels of CD3+, CD4+, and CD4+/CD8+ ratio in the control group were significantly higher than those in the ulcer group, with statistically significant difference (P<0.05); while the level of IgG in the control group was lower than that in the ulcer group, with statistically significant difference (P<0.05). Meanwhile, there were statistically significant differences in that the levels of CD3+, CD4+ and CD8+ were increased in Hp-positive group than those in Hp-negative group before treatment (P<0.05); while CD4+/CD8+ ratio was lower in the former group than that in the latter group, with statistically significant difference (P<0.05). Conclusion: Hp infection can induce the elevation of T lymphocyte subsets. The development of peptic ulcer has an intimate association with the disorder of cellular and humoral immune functions.

Zr modulated N doping composites for CO2 conversion into carbonates.

Acidic and basic sites of catalysts are essential for CO2 capture and activation. In this work, Zr, N-ZnO/ZnAl-LDH-IL composites in ionic liquid and methanol systems were fabricated, and applied to catalyze the synthesis of ethylene carbonate (EC) from ethylene glycol (EG) and CO2 with about 4.76 mmolEC gCat.-1 h-1. The composites showed more strong basic sites due to the effective induction of reactive groups on the catalyst surface by Zr doping, resulting in an increase of pyridinic-N groups from 5.48% to 22.25%. More C atoms adjacent to pyridinic-N as strong basic sites was conducive to the activation of CO2 and EG. In addition, the possible catalytic pathway and mechanism of the composites for synthesizing EC as well as the doping of La, Fe, Ce, and Cu were also investigated, which provides an effective strategy for regulating the acid-base centers on the catalyst surface through ionic liquids and methanol solvents.

Studies on the Prediction and Extraction of Methanol and Dimethyl Carbonate by Hydroxyl Ammonium Ionic Liquids.

The separation of dimethyl carbonate (DMC) and methanol is of great significance in industry. In this study, ionic liquids (ILs) were employed as extractants for the efficient separation of methanol from DMC. Using the COSMO-RS model, the extraction performance of ILs consisting of 22 anions and 15 cations was calculated, and the results showed that the extraction performance of ILs with hydroxylamine as the cation was much better. The extraction mechanism of these functionalized ILs was analyzed by molecular interaction and the σ-profile method. The results showed that the hydrogen bonding energy dominated the interaction force between the IL and methanol, and the molecular interaction between the IL and DMC was mainly Van der Waals force. The molecular interaction changes with the type of anion and cation, which in turn affects the extraction performance of ILs. Five hydroxyl ammonium ILs were screened and synthesized for extraction experiments to verify the reliability of the COSMO-RS model. The results showed that the order of selectivity of ILs predicted by the COSMO-RS model was consistent with the experimental results, and ethanolamine acetate ([MEA][Ac]) had the best extraction performance. After four regeneration and reuse cycles, the extraction performance of [MEA][Ac] was not notably reduced, and it is expected to have industrial applications in the separation of methanol and DMC.

Effects of inflammatory cytokines on eradication and recurrence of Helicobacter pylori infection in children.

Objectives: To study the correlation of eradication and recurrence with IL-1 ß, IL-6 and TNF-α levels in children with Helicobacter pylori (Hp) infection. Methods: Children confirmed with Hp infection (n = 153) in our hospital from January to June 2019 and successfully followed up for one year were selected as the study subjects, and 73 healthy children of the same period were selected as the control group. The levels of IL-1 ß, IL-6 and TNF-α in children confirmed with Hp infection and healthy children were detected, respectively. Results: Results of triple therapy: 113 cases (73.9%) reexamined with negative 13C-urea breath test were included in Group-A; and 40 cases (26.1%) reexamined with positive 13C-urea breath test were included in Group-B. Follow up results: 23 cases (20.4%) positive in 13C-urea breath test in one year follow-up were included in Group-C; and 90 cases (79.6%) negative in 13C-urea breath test in one year follow-up were included in Group-D. Group-B showed significantly higher levels of IL-1ß, IL-6 and TNF-α when compared with the Group-A and the control group, respectively (P < 0.05). Obviously higher levels of IL-1ß, IL-6 and TNF-α were observed in Group-C and Group-D in comparison with the control group (P < 0.05). There was no significant difference in IL-1 ß level between Group-C and Group-D (P > 0.05). IL-6 and TNF-α levels in Group-C were remarkably higher than those in Group-D (P < 0.05). Conclusions: Higher levels of IL-1ß, IL-6 and TNF-α may affect the eradication effect of triple therapy in Children with Hp infection, and increased levels of IL-6 and TNF-α may affect the recurrence rate of Hp infection in children.

Kinetic isotope effects of C and N indicate different transformation mechanisms between atzA- and trzN-harboring strains in dechlorination of atrazine.

Compound-specific stable isotope analysis provides an alternative method to insight into the biotransformation mechanisms of diffuse organic pollutants in the environment, e.g., the endocrine disruptor herbicide atrazine. Biotic hydrolysis process catalyzed by chlorohydrolase AtzA and TrzN plays an important role in the detoxification of atrazine, while the catalytic mechanism of AtzA is still speculative. To investigate the catalytic mechanism of AtzA and answer whether both enzymes catalyze hydrolytic dechlorination of atrazine by the same mechanism, in this study, apparent kinetic isotope effects (AKIE) for carbon and nitrogen were observed by three atzA-harboring bacterial isolates and their membrane-free extracts. The AKIEs obtained from atzA-harboring bacterial isolates (AKIEC = 1.021 ± 0.010, AKIEN = 0.992 ± 0.003) were statistically different from that of trzN-harboring strains (AKIEC = 1.040 ± 0.006, AKIEN = 0.983 ± 0.006), confirming the different activation mechanisms of atrazine preceding to nucleophilic aromatic substitution of Cl atom in actual enzymatic reaction catalyzed by AtzA and TrzN, despite the limitation of variable dual-element isotope plots. The lower degree of normal carbon and inverse nitrogen isotope fractionation observed from atzA-harboring strains, suggesting AtzA catalyzing hydrolytic dechlorination of atrazine by coordination of Cl and one aromatic N to the Fe2+ drawing electron density from carbon-chlorine bond that facilitating the nucleophilic attack, rather than in TrzN case that protonation of aromatic N increasing nucleophilic substitution of Cl atom. This study suggests considering the potential influences of phylogenetic diversity of bacterial isolates and evolution of enzymes on the applications of CSIA method in future study.

Towards future physics and applications via two-dimensional material NEMS resonators.

Two-dimensional materials (2Dm) offer a unique insight into the world of quantum mechanics including van der Waals (vdWs) interactions, exciton dynamics and various other nanoscale phenomena. 2Dm are a growing family consisting of graphene, hexagonal-Boron Nitride (h-BN), transition metal dichalcogenides (TMDs), monochalcogenides (MNs), black phosphorus (BP), MXenes and 2D organic crystals such as small molecules (e.g., pentacene, C8 BTBT, perylene derivatives, etc.) and polymers (e.g., COF and MOF, etc.). They exhibit unique mechanical, electrical, optical and optoelectronic properties that are highly enhanced as the surface to volume ratio increases, resulting from the transition of bulk to the few- to mono- layer limit. Such unique attributes include the manifestation of highly tuneable bandgap semiconductors, reduced dielectric screening, highly enhanced many body interactions, the ability to withstand high strains, ferromagnetism, piezoelectric and flexoelectric effects. Using 2Dm for mechanical resonators has become a promising field in nanoelectromechanical systems (NEMS) for applications involving sensors and condensed matter physics investigations. 2Dm NEMS resonators react with their environment, exhibit highly nonlinear behaviour from tension induced stiffening effects and couple different physics domains. The small size and high stiffness of these devices possess the potential of highly enhanced force sensitivities for measuring a wide variety of un-investigated physical forces. This review highlights current research in 2Dm NEMS resonators from fundamental physics and an applications standpoint, as well as presenting future possibilities using these devices.

Synthesis, Transfer, and Properties of Layered FeTe2 Nanocrystals.

Different from layered two-dimensional (2D) transition metal dichalcogenides (TMDs), iron dichalcogenides crystallize in the most common three-dimensional pyrite or marcasite structures. Layered iron dichalcogenides are rarely reported and little is known about their structures and properties. Here, layered hexagonal phase iron ditelluride FeTe2 (h-FeTe2) nanocrystals are grown on mica by atmospheric pressure chemical vapor deposition (APCVD) method and are fully characterized by various methods. Like other 2D layered TMD materials, the FeTe2 nanoflakes exhibit regular hexagon, half hexagon, or triangle shapes with a controllable thickness of 6-95 nm and lateral length from a few to tens of micrometers. A simple and effective method is used to transfer the FeTe2 nanoflakes from the mica substrate onto any other substrates without quality deterioration by using polystyrene (PS) as a support polymer, which can also be operated in ethanol or ethylene glycol in a glovebox to avoid contact with water and air. Temperature-dependent electrical transport demonstrates that the FeTe2 nanoflake is a semiconductor with a variable range hopping (VRH) conduction, and its nonsaturated linear magnetoresistance (MR) reaches up to 10.4% under magnetic field of 9 T at 2 K, both probably due to its structure disorders. No signature of magnetic ordering is observed down to 2 K. The CVD growth of this layered FeTe2 represents an addition to the extensive library of 2D materials, particularly iron chalcogenides or alloys. Synthesis, properties, and even doping of phase pure h-FeTe2 call for further study in the future.

A Symmetry-Breaking Phase in Two-Dimensional FeTe2 with Ferromagnetism above Room Temperature.

Recently, ferromagnetism observed in monolayer two-dimensional (2D) materials has attracted attention due to the promise of its application in next-generation spintronics. Here, we predict a symmetry-breaking phase in 2D FeTe2 that differs from conventional transition metal ditellurides shows superior stability and room-temperature ferromagnetism. Through density functional theory calculations, we find the exchange interactions in FeTe2 consist of short-range superexchange and long-range oscillatory exchanges mediated by itinerant electrons. For six nearest neighbors, the exchange constants are calculated to be 50.95, 33.41, 2.70, 11.02, 14.46, and -4.12 meV. Furthermore, the strong relativistic effects on Te2+ induce giant out-of-plane exchange anisotropy and open up a significantly large spin wave gap (ΔSW) of 1.22 meV. All of this leads to robust ferromagnetism with the Tc surpassing 423 K, which is predicted by the renormalization group Monte Carlo method, sufficiently higher than room temperature. Our findings shed light on the promising future of FeTe2 in 2D magnetic research and spintronic applications.

Impact of atrazine concentration on bioavailability and apparent isotope fractionation in Gram-negative Rhizobium sp. CX-Z.

Compound-specific stable isotope analysis of micropollutants has become an established method for the qualitative and quantitative assessment of biodegradation in the field. However, many of environmental factors may have an influence on the observed isotope fractionation. Herein, we investigate the impact of substrate concentration on the observed enrichment factor derived from Rayleigh plot of batch laboratory experiments conducted to measure the atrazine carbon isotope fractionation of Rhizobium sp. CX-Z subjected to the different initial concentration level of atrazine. The Rayleigh plot (changes in bulk concentration vs. isotopic composition) derived from batch experiments shown divergence from the linear relation towards the end of degradation, confirming bioavailability of atrazine changed along with the decay of substrate concentration, consequently, influenced the isotope fractionation and lowered the observed enrichment factor. When microbial degradation is coupled to a mass transfer step limiting the bioavailability of substrate, the observed enrichment factor displays a dependence on initial atrazine concentration. Observed enrichment factors (ε) (absolute value) derived from the low concentration (i.e. 9.5 µM) are below 3.5‰ to the value of -5.4‰ determined at high bioavailability (membrane-free cells). The observed enrichment factor depended significantly on the atrazine concentration, indicating the concentration level and the bioavailability of a substrate in realistic environments should be considered during the assessment of microbial degradation or in situ bioremediation based on compound-specific stable isotope analysis (CSIA) method.

Isotope fractionation in atrazine degradation reveals rate-limiting, energy-dependent transport across the cell membrane of gram-negative rhizobium sp. CX-Z.

In the biological mass transfer of organic contaminants like atrazine, the cellular membrane limits bioavailability of pesticides. We aimed to illustrate the roles of cellular membrane physiology and substrate uptake (e.g., passive diffusion and energy-dependent transport) on the limitations of bioavailability in atrazine biodegradation by Gram-negative strain Rhizobium sp. CX-Z. Compound-specific stable isotope analysis revealed energy-dependent transport across cellular membrane led to bioavailability limitations in atrazine biotransformation. Carbon isotope fractionation (ε(C) = -1.8 ±â€¯0.3‰) was observed and significantly smaller in atrazine biodegradation by Rhizobium sp. CX-Z than that expected in acid hydrolysis (ε(C) = -4.8 ±â€¯0.4‰) and hydrolysis by the pure enzyme TrzN (ε(C) = -5.0 ±â€¯0.2‰). However, isotope fractionation was restored in membrane-free cells of Rhizobium sp. CX-Z (ε(C) = -5.4 ±â€¯0.2‰) where no cellular membrane limits substrate uptake. When respiratory chain was inhibited by rotenone, the pseudo-first order kinetic rate constants (0.08 ±â€¯0.03 h-1, 0.09 ±â€¯0.03 h-1) was observed to be statistically less than in the control group (0.23 ±â€¯0.02 h-1, 0.33 ±â€¯0.02 h-1), demonstrating that energy-dependent transport dominated atrazine transfer across the cellular membrane. Therefore, our results revealed energy-dependent transport across cellular membrane existing in Gram-negative strain Rhizobium sp. CX-Z determines bioavailability of atrazine in biotransformation process even at high concentration.

In-Plane Isotropic/Anisotropic 2D van der Waals Heterostructures for Future Devices.

Mono- to few-layers of 2D semiconducting materials have uniquely inherent optical, electronic, and magnetic properties that make them ideal for probing fundamental scientific phenomena up to the 2D quantum limit and exploring their emerging technological applications. This Review focuses on the fundamental optoelectronic studies and potential applications of in-plane isotropic/anisotropic 2D semiconducting heterostructures. Strong light-matter interaction, reduced dimensionality, and dielectric screening in mono- to few-layers of 2D semiconducting materials result in strong many-body interactions, leading to the formation of robust quasiparticles such as excitons, trions, and biexcitons. An in-plane isotropic nature leads to the quasi-2D particles, whereas, an anisotropic nature leads to quasi-1D particles. Hence, in-plane isotropic/anisotropic 2D heterostructures lead to the formation of quasi-1D/2D particle systems allowing for the manipulation of high binding energy quasi-1D particle populations for use in a wide variety of applications. This Review emphasizes an exciting 1D-2D particles dynamic in such heterostructures and their potential for high-performance photoemitters and exciton-polariton lasers. Moreover, their scopes are also broadened in thermoelectricity, piezoelectricity, photostriction, energy storage, hydrogen evolution reactions, and chemical sensor fields. The unique in-plane isotropic/anisotropic 2D heterostructures may open the possibility of engineering smart devices in the nanodomain with complex opto-electromechanical functions.

Activation of P2X3 receptors in the cerebrospinal fluid-contacting nucleus neurons reduces formalin-induced pain behavior via PAG in a rat model.

The cerebrospinal fluid (CSF)-contacting nucleus is implicated in the descending inhibitory pathway in pain processing, whereas the cellular and molecular mechanisms underpinning CSF-contacting nucleus regulating pain signals remains largely elusive. ATP is evidenced to inhibit pain transmission at supraspinal level by the mediation of the receptor P2X, wherein its subtype P2X3 is identified as the most potent. Our present experiment investigated the functionality of P2X3 receptors in CSF-contacting nucleus in the formalin-evoked inflammatory pain. Immunofluorescence and western blot revealed the expression of P2X3 receptors in the CSF-contacting nucleus and their upregulated expression subsequent to administration of formalin in rat model. ATP (a P2X3 receptor agonist, 100nmol/5µl) by intracerebroventricular (i.c.v.) administration ameliorated pain behaviors and enhanced c-Fos immunoreactivity in the neurons of the periaqueductal gray (PAG), both of which were discounted by pre-administration of A-317491 (a selective P2X3 receptor antagonist, 25nmol/5µl). After the CSF-contacting nucleus was ablated by cholera toxin subunit B-saporin, ATP failed to induce analgesia, with the c-Fos immunoreactivity in the PAG neurons remaining intact. Our results validated that P2X3 receptors in the CSF-contacting nucleus are pivotal in inflammatory pain processing via the activation of PAG neurons.

Role of the RVM in Descending Pain Regulation Originating from the Cerebrospinal Fluid-Contacting Nucleus.

Evidence has suggested that cerebrospinal fluid-contacting nucleus (CSF-contacting nucleus) is correlated with the development and recurrence of pain. A recent research showed that the CSF-contacting nucleus acts as a component of the descending 5-hydroxytryptamine (5-HT) system and plays a role in descending pain inhibition. However, limited studies are conducted to investigate the relationship between the CSF-contacting nucleus and pain. In present study, we explored the effect of CSF-contacting nucleus on nociceptive behaviors in both normal and neuropathic rats via targeted ablation of the CSF-contacting nucleus in the brainstem, using cholera toxin subunit B-saporin (CB-SAP), a cytotoxin coupled to cholera toxin subunit B. The CB-SAP-treated rats showed aggravated thermal hyperalgesia and mechanical allodynia. Also, results from immunohistochemical experiments showed that rostral ventromedial medulla (RVM) received fiber projection from the CSF-contacting nucleus, which disappeared after ablation of the CSF-contacting nucleus, and the CB-SAP treated rats showed downregulation of c-Fos expression in the RVM as compared with the rats receiving i.c.v. injection of phosphate buffer saline (PBS). A significant downregulation of 5-HT-labeled neurons and tryptophan hydroxylase 2 (TPH2) as the marker of 5-HT cells in the RVM, and 5-HT expression in spinal dorsal horn in both normal and chronic constriction injury (CCI) rats after i.c.v. injection of CB-SAP was observed. These results suggested that RVM may be involved in descending pain modulation originating from the CSF-contacting nucleus.