Weak Reaction Research Articles

Hyperbranched Vitrimer for Ultrahigh Energy Dissipation.

Polymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate-2-(4-ethenylphenyl)-5,5-dimethyl-1,3,2-dioxaborinane) P(HMA-co-ViCL) copolymers. The -type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high-performance HBV damping materials. We found that P(HMA-co-ViCL) 20k-40-60 HBV exhibited ultrahigh energy-dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials.

Hyperbranched Vitrimer for Ultrahigh Energy Dissipation

AbstractPolymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate‐2‐(4‐ethenylphenyl)‐5,5‐dimethyl‐1,3,2‐dioxaborinane) P(HMA‐co‐ViCL) copolymers. The ‐type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high‐performance HBV damping materials. We found that P(HMA‐co‐ViCL) 20k‐40‐60 HBV exhibited ultrahigh energy‐dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials.

The Identification Idea of Antibodies Against Ku and Other High-Frequency Antigens

This study was aimed to provide ideas for identifying the antibodies to high-frequency antigens by analyzing a female case of high-frequency antigen antibody (anti-Ku) using serological and sequencing method. The methods for identification of blood group, erythrocyte antigen, screening and identification of antibody were used to detect the blood type and antibody in the proband. The proband's serum and reagent screening cells treated with Sulfhydryl reagent were applied to judge the type and characteristics of this antibodies when reacted with the regaent screening cells or proband's serum respectively. Gene sequencing was used to determine the genotype of the proband's blood group. The proband's red blood cells were determined as O type RhD positive, whose serum showed strong positive reaction to antibody-screening cells and antibody identification cells with the same intensity in saline and IAT medium, however, the self-cells showed negative effect. The Direct Antihuman Globulin of proband's red blood cells also showed weak positive reaction, and the other blood types were CcEe, Jk(a+b-), P1-, Le(a-b -), Lu (a-b +), K-, k-, Kp(a-b-). Serum of the proband treated with 2-ME still react with three groups of screening cells in IAT medium. The reaction intensity of proband's serum was also unchanged with the cells modified with papain and bromelain, but showed negative effect when the cells were treated with sulfhydryl agents including DTT and 2-ME. Gene sequencing revealed that the KEL genotype of the patient was KEL*02N.24 . This patient had a rare K0 phenotype. The rare Kell-null blood group (also known as K0) were identified by serological and molecular tests in the proband who produced both IgG and IgM type of antibody to high-frequency antigen (anti-Ku). These two methods are of great significance in the identification of this rare blood group as well as the antibody to high frequency antigen.

Serologic profiling of D variants in donor routine: unveiling the impact on false-negative results and alloimmunization.

The high number of D variants can lead to the unnecessary use of Rh immune globulin, overuse of D- RBC units, and anti-D allommunization. D variant prevalence varies among ethnic groups, and knowledge of the main variants present in a specific population, their behavior in serologic tests, and their impact on clinical practice is crucial to define the best serologic tests for routine use. The present study aimed to explore the serologic profile of D variants and to determine which variants are most associated with false-negative D typing results and alloimmunization. Donor samples were selected in two study periods. During the first period, D typing was performed on a semi-automated instrument in microplates, and weak D tests were conducted in tube or gel tests. In the second period, D typing was carried out using an automated instrument with microplates, and weak D tests were performed in solid phase. Samples from patients typed as D+ with anti-D were also selected. All samples were characterized by molecular testing. A total of 37 RHD variants were identified. Discrepancies and atypical reactivity without anti-D formation were observed in 83.4 percent of the samples, discrepant D typing results between donations were seen in 12.3 percent, and D+ patients with anti-D comprised 4.3 percent. DAR1.2 was the most prevalent variant. Weak D type 38 was responsible for 75 percent of discrepant samples, followed by weak D type 11, predominantly detected by solid phase. Among the D variants related to alloimmunization, DIVa was the most prevalent, which was not recognized by serologic testing; the same was true for DIIIc. The results highlight the importance of selecting tests for donor screening capable of detecting weak D types 38 and 11, especially in populations where these variants are more prevalent. In pre-transfusion testing, it is crucial that D typing reagents demonstrate weak reactivity with DAR variants; having a serologic strategy to recognize DIVa and DIIIc is also valuable.

Strength evolution and microstructure of alkali-activated ultra-fine slag in low-temperature environments

At low temperatures, the hydration rate of Portland cement significantly slows down, resulting in a decrease in its strength. Additionally, the pore solution freezes easily. As a kind of low-carbon cementitious material, alkali-activated slag (AAS) material has a short setting time at room temperature and a high early strength, meanwhile the alkali solution does not freeze at low temperatures. This study investigates the evolution mechanism of the strength and microstructure of AAS pastes cured at 0℃. Slag with different fineness was activated by a sodium silicate solution with different moduli, whose strength was compared with that of an AAS paste cured at 20 °C. The setting time, compressive strength, hydration process, pore structure, freezing point, and microstructure of the AAS paste were studied, whose results showed that the setting time of the AAS paste was obviously prolonged, and the compressive strength decreased under low-temperature curing. After the activation of slag ground, the early compressive strength of the AAS paste was significantly improved, whose reason was that the hydration degree of the paste was improved after slag ground, and that a dense pore structure was formed. The freezing point of the AAS paste was approximately −26 °C, which, remarkably, even at −40 °C, was still capable of undergoing a weak chemical reaction, producing an exothermic enthalpy. This characteristic makes alkali-activated ultrafine slag a highiy-promising cementitious material for curing at low temperatures.

Gender impact on consumer perception of packaging colour based on neuromarketing algorithms

The introduction of neuromarketing tools has created additional opportunities for deciphering consumer behaviour through studying neurophysiological responses to marketing incentives. The article aims to examine the effect of packaging colour on consumer behaviour when choosing cheese products. The principles of sensory marketing constitute the methodological framework of the study. It applies neurophysiological methods to investigate consumer reactions during visual examination of the packaging colour. Electroencephalogram (EEG) recordings and emotional responses identified by the Facial Action Coding System are used as empirical evidence. Vectors of emotional response were assessed using EmoDetect software. The research results show that the cheese packaging colour affects consumer choice, and its perception varies by gender and product group. According to EEG data analysis, the most intense emotional response in women was triggered by red cheese packaging, while blue packaging produced the least intense reaction. In men, it was black and white colours of boxes that induced the strongest and the weakest reaction, respectively. In women, a positive emotional response was recorded during visual examination of white and red cheese packaging, in men – of black ones. The most intense negative reactions were associated with blue and white packaging in women and men, respectively. Our study confirms that there are differences in emotional perception of the packaging colour between women and men, which should be considered by manufacturers to capture and keep consumer attention when marketing their products.

Physical modeling of ice-sheet-induced salt movements using the example of northern Germany

Abstract. Salt structures and their surroundings can play an important role in the energy transition related to a number of storage and energy applications. Thus, it is important to assess the current and future stability of salt bodies in their specific geological settings. We investigate the influence of ice sheet loading and unloading on subsurface salt structures using physical models based on the geological setting of northern Germany, which was repeatedly glaciated by the Scandinavian Ice Sheet during the Pleistocene. Apparent spatial correlations between subsurface salt structures in northern Germany and Weichselian ice marginal positions have been observed before, and the topic is a matter of ongoing debate. Recently described geomorphological features – termed surface cracks – have been interpreted as a direct result of ice-sheet-induced salt movement resulting in surface expansion. The spatial clustering and orientation of these surface cracks has not been well understood so far, owing to only a limited number of available studies dealing with the related salt tectonic processes. Thus, we use four increasingly complex physical models to test the basic loading and unloading principle, to analyze flow patterns within the salt source layer and within salt structures, and to examine the influence of the shape and orientation of the salt structures with respect to a lobate ice margin in a three-dimensional laboratory environment. Three salt structures of the northern German basin were selected as examples that were replicated in the laboratory. Salt structures were initially grown by differential loading and buried before loading. The ice load was simulated by a weight that was temporarily placed on a portion of the surface of the models. The replicated salt structures were either completely covered by the load, partly covered by the load, or situated outside the load extent. In all scenarios, a dynamic response of the system to the load could be observed; while the load was applied, the structures outside the load margin started to rise, with a decreasing tendency with distance from the load margin, and, at the same time, the structures under the load subsided. After the load was removed, a flow reversal set in, and previously loaded structures started to rise, whereas the structures outside the former load margin began to subside. The vertical displacements during the unloading stage were not as strong as during the load stage, and thus the system did not return to its pre-glaciation status. Modeled salt domes that were located at distance from the load margin showed a comparably weak reaction. A more extreme response was shown by modeled salt pillows whose margins varied from sub-parallel to sub-perpendicular to the load margin and were partly covered by the load. Under these conditions, the structures showed a strong reaction in terms of strain and vertical displacement. The observed strain patterns at the surface were influenced by the shape of the load margin and the shape of the salt structure at depth, resulting in complex deformation patterns. These physical modeling results provide more evidence for a possible interplay between ice sheets and subsurface salt structures, highlighting the significance of three-dimensional effects in dynamic geological settings. Our results lead to a better understanding of spatial patterns of the surface cracks that were mapped at the surface above salt structures and offer further room for interpretation of the influence of salt movements on the present-day landscape.

Assessment of the antibacterial efficacy of silver nanoparticles-based Artemisia annua against methicillin-resistant Staphylococcus aureus-infected lung tissues in albino rats

The production of alternative and effective medicines is crucial given that antibiotic resistance is currently a global health concern. Several biochemical identification tests were used to screen for Staphylococcus aureus isolates. Analysis of Artemisia annua extract was performed using a trace GC‒mass spectrometer, which revealed that the A. annua extract contains numerous compounds, such as artemisinins, palmitic acid and other vital essential compounds that have antioxidant and anti-inflammatory properties. The isolate st.8 was resistant to cefoxitin, oxacillin, and cephalosporins; furthermore, MALDI-TOF/MS Biotyper® identified it as methicillin-resistant S. aureus with confidence value 99.9% of mass spectrum compared with reference spectra. The synthesis of green silver nanoparticles based on A. annua as a reducing agent was confirmed via partial characterizations: (HR-TEM), (XRD), (SEM), (EDX) and (FTIR) analysis. The significant of antibacterial activity of the new green material (AgNPs) was achieved by determining the agar well diffusion assay. Furthermore, compared with those in the Staphylococcus-infected group, a significant decrease in hematological parameters was observed, with an increase in antioxidant biomarkers, a decrease in interstitial tissue thickening by inflammatory cells, and a weak positive immune reaction in a few cells (TNF-α and iNOS) in rats. Overall, this study is a promising step toward the development of new and effective strategies for combating MRSA infections.

Combined effect of pantoprazole and mesenchymal stem cells on experimentally induced gastric ulcer: implication of oxidative stress, inflammation and apoptosis pathways

Gastric ulcer (GU) is one of the most common diseases of the upper gastrointestinal tract that affects millions of people worldwide. This study aimed to investigate the possible alleviating effect of a combined treatment of pantoprazole (PANTO) and adipose tissue-derived mesenchymal stem cells (ADSCs) in comparison with each treatment alone on the healing process of the experimentally induced GU in rats, and to uncover the involved pathways. Rats were divided into five groups: (1) Control, (2) GU, (3) PANTO, (4) ADSCs and (5) ADSCs + PANTO. Markers of oxidative stress, inflammation and apoptosis were assessed. The current data indicated that PANTO-, ADSCs- and ADSCs + PANTO-treated groups showed significant drop (p < 0.05) in serum advanced oxidation protein products (AOPPs) and advanced glycation end products (AGEPs) along with significant elevation (p < 0.05) in serum TAC versus the untreated GU group. Moreover, the treated groups (PANTO, ADSCs and ADSCs + PANTO) displayed significant down-regulation (p < 0.05) in gastric nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), intercellular adhesion molecule-1 (ICAM-1), matrix metallopeptidase 9 (MMP-9) and caspase-3 along with significant up-regulation (p < 0.05) in vascular endothelial growth factor (VEGF) and peroxisome proliferator-activated receptor gamma (PPARγ) genes expression compared to the untreated GU group. Immunohistochemical examination of gastric tissue for transforming growth factor β1 (TGF-β1), epidermal growth factor (EGF) and proliferating cell nuclear antigen (PCNA) showed moderate to mild and weak immune reactions, respectively in the PANTO-, ADSCs- and ADSCs + PANTO-treated rat. Histopathological investigation of gastric tissue revealed moderate to slight histopathological alterations and almost normal histological features of the epithelial cells, gastric mucosal layer, muscularis mucosa and submucosa in PANTO-, ADSCs- and ADSCs + PANTO-treated rats, respectively. Conclusively, the co-treatment with ADSCs and PANTO evidenced sententious physiological protection against GU by suppressing oxidative stress, inhibiting inflammation and reducing apoptosis with consequent acceleration of gastric tissue healing process.

The relationship between oxidative stress and apoptosis of histopathological changes in the ovary made by mad honey containing grayanotoxin

The purpose of this study is to determine the effects of grayanotoxin in mad honey on ovarian tissue folliculogenesis in terms of cell death and nitric oxide expression. Three groups of 18 female Sprague-Dawley rats were formed. The first group received mad honey (80 mg/kg), the second group received normal honey (80 mg/kg), and the third group was the control. The first and second groups received normal and mad honey by oral gavage for 30 days before being sacrificed under anesthesia. Caspase 3 immunostaining showed a moderate to strong response, particularly in the mad honey group. In the mad honey group, immunostaining for caspase 8 and caspase 9 revealed a moderate immunoreaction in the granulosa cells of the Graaf follicles. The majority of Graaf follicles exhibited TUNEL positive in the mad honey group. The iNOS immunoreaction revealed a high level of expression in the mad honey group. In all three groups, eNOS immunostaining showed weak reactivity. According to the findings of apoptotic and nitric oxide marker expression, it was determined that mad honey may result in an increase in follicular atresia in ovarian follicles when compared to normal honey and control groups.

Sensitivity of 3D Convective Urca Simulations to Changes in Urca Reactions

A proposed setting for thermonuclear (Type Ia) supernovae is a white dwarf that has gained mass from a companion to the point of carbon ignition in the core. There is a simmering phase in the early stages of burning that involves the formation and growth of a core convection zone. One aspect of this phase is the convective Urca process, a linking of weak nuclear reactions to convection that may alter the composition and structure of the white dwarf. Convective Urca is not well understood and requires 3D fluid simulations to realistically model. Additionally, the convection is relatively slow (Mach number less than 0.005) so a low-Mach method is needed to make simulating computationally feasible. Using the MAESTROeX low-Mach hydrodynamics code, we investigate recent changes to how the weak reactions are modeled in the convective Urca simulations. We present results that quantify the changes to the reaction rates and their impact on the evolution of the simulation.

Effect of carbon nanotubes content on compressive properties and deformation behaviors of aluminum matrix composite foams

The incorporation of nano carbon reinforcement is a useful strategy to broaden the engineering applications of metal foams. In this work, carbon nanotubes (CNTs) reinforced aluminum (Al) matrix composite foams (CNTs/Al composite foams) with different CNTs content are prepared by combining ball-milling technique with powder metallurgy method. The result shows that the appropriate content of CNTs can reduce the pore size, improve the circularity, and enhance the compressive properties. Especially, the 1.0 wt% CNTs/Al composite foams possess the optimal compressive properties of yield stress (7.90 MPa), plateau stress (8.75 MPa) and energy absorption capacity (5.19 MJ/m3), which have an enhancement of 23.24%, 98.41% and 84.70%, respectively. Composite foams undergo shear deformation throughout the quasi-static compression process, and the failure mode performs as the brittle mode combined with ductile mode. Meanwhile, the incorporation of CNTs can contribute to the inhomogeneous distribution of the Si phase, provide more nucleation sites, and significantly refine the pore size. It is confirmed that the CNTs in composite foams contribute the grain refinement and the formation of micro stacking faults, making the mechanical properties of CNTs/Al composite foams outperform the counterpart of Al-Si foams. Moreover, due to the weak interfacial reaction, the low content of aluminum carbide is formed, which can promote the load transfer between CNTs and Al. The present finding provides a theoretical and practical design strategy to the future preparation of CNTs/Al composite foams.

Papillary renal neoplasm with reverse polarity is biologically and clinically distinct from eosinophilic papillary renal cell carcinoma.

Papillary renal neoplasm with reverse polarity (PRNRP) is a recently described indolent entity with distinct features and its recognition from other oncocytic/eosinophilic papillary renal cell carcinoma (ePRCC) has important prognostic implications. ABCC2, a renal drug transporter, is overexpressed in aggressive PRCCs. In this study, we compared the clinicopathological parameters and the biological ABCC2 expression between PRNRP and ePRCC. PRNRP (n = 8) and ePRCC (n = 21) cases were selected from resection specimens and corresponding clinicopathological data were collected. ABCC2 immunohistochemical (IHC) staining was performed and ABCC2 staining patterns were classified as negative, cytoplasmic, and brush-border. RNA in-situ hybridization (ISH) was used to assess ABCC2 transcript levels. All eight PRNRP cases had weak cytoplasmic ABCC2 IHC reactivity; however, they showed no detectable ABCC2 transcripts on RNA ISH. In comparison, 76% (16/21) of ePRCCs showed ABCC2 IHC brush-border expression and significantly higher ABCC2 RNA ISH transcript levels (p < 0.001). Additionally, the ePRCC group showed a significantly larger tumor size (p = 0.004), higher WHO/ISUP grade (p < 0.001), and stage (p = 0.044). None of the PRNRP cases showed disease progression, while 9.5% (2/21) ePRCCs had disease progression. PRNRP is clinically and biologically distinct from ePRCC. Hence, it is crucial to differentiate between these two entities, particularly in needle core biopsies.

Nano zero-valent iron functioned 3D printing graphene aerogel electrode for efficient solar-driven biocatalytic methane production

To address the urgent need for developing carbon-neutral technologies, microbial electrosynthesis (MES), as an important contributor to the renewable energy field, can convert carbon dioxide to multi-carbon chemicals using microbes serving as living catalysts at the cathode. However, the performance of the cathode is restricted by the weak electrochemical reaction kinetics of the organisms, the specific area of the electrode, and the mass transfer under high current. Herein, we report a facile 3D-printed graphene aerogel (GA) electrode built with a nanozero-valent iron (NZVI)-functionalized graphene ink. The 3D-printed GA electrode was designed to possess hierarchical pores with an enhanced high specific surface area for microbial colonization while ensuring mass transfer. NZVI can assist in-situ hydrogen generation, facilitating biofilm formation and methane (CH4) production in the indirect electron transfer pathway. Consequently, the optimized 3D-printed electrode achieved a maximum CH4 production rate of 6993 ± 832 mmol/m2/d with a faradaic efficiency of 83.7%, which increased by 3.24-fold to the carbon felt electrode. In addition, integrating the proposed cathode into a PV-electrolyzer cell yielded a solar-to-CH4 efficiency of 4.70%. This study provides a unique method for the development of advanced cathodes and underscores the potential of integrating MES with renewable energy technologies.

Study on Rheological Properties and Modification Mechanism of Budun Rock Asphalt/Nano-Silica Composite Modified Asphalt

To enhance the high and low-temperature performance of asphalt materials and extend the service life of asphalt pavement, two types of external admixtures, Butonite rock asphalt, and nano-silica are added to the asphalt. By conducting dynamic shear rheological tests and bending creep stiffness tests, the high and low-temperature rheological properties of Budun rock asphalt/nano-silica composite-modified asphalt were evaluated. The distribution of Budun rock asphalt and nano-silica in asphalt was studied using scanning electron microscopy and infrared spectroscopy tests, revealing the synergistic modification mechanism of Budun rock asphalt and nano-silica. The results show that the optimal dosage of Butonite rock asphalt and nano-silica composite-modified asphalt is 25% and 5%, respectively. At this dosage, the rutting factor G*/sinδ of composite-modified asphalt at 82 °C Compared with the matrix asphalt, the frequency main curve of Budun rock asphalt/nano-silica composite-modified asphalt is higher than that of the matrix asphalt and nano-silica-modified asphalt by 4 kPa. The creep modulus S at −18 °C decreases by 117.2 MPa, indicating that the high-temperature performance, low-temperature performance, and temperature sensitivity of Budun rock asphalt/nano-silica composite-modified asphalt are significantly improved compared to the matrix asphalt; The distribution of nano-silica particles in Budun rock asphalt/nano-silica composite-modified asphalt is uniform, and together with Budun rock asphalt, it forms a stable three-dimensional network skeleton structure; Budun rock asphalt/nano-silica composite-modified asphalt has generated new functional groups, and the blending process is mainly based on physical reactions, supplemented by weak chemical reactions.

Analyzing the factors associated with efficacy among teriparatide treatment in postmenopausal women with osteoporosis

BackgroundTeriparatide (TPTD) is a widely used anabolic agent for the treatment of osteoporosis. Several factors have been identified to be related to bone mineral density (BMD) increase in anti-osteoporosis treatment with other agents; however, there has been no systematic analysis to summarize the associated determinants of BMD reaction to daily teriparatide treatment.MethodsIn this retrospective study, we performed a comprehensive investigation involving not only clinical data but also several relevant lifestyle factors to be examined for their potential contribution to BMD response. This post-hoc analysis included 258 post-menopaused patients with osteoporosis who received TPTD at 20 µg/day for 12 months. Univariate and multivariate analyses were conducted to distinguish the response variables of lumbar spine (LS) BMD transformation, the principal outcome measure of efficacy, from the baseline at 12 months.ResultsTwelve months of TPTD treatment resulted in an absolute 0.39 ± 0.37 increase in T-score of LS BMD. Gastrointestinal disease, prior bisphosphonate or glucocorticoid treatment, no vitamin K2 supplementation, low levels of serum 25(OH)D and PINP, weak increment of PINP and β-CTX at 3 months, unhealthy lifestyle (excessive smoking, tea, coffee, and drinking), vegetarian diet pattern, low ALT level, and high BMD at baseline were determined by univariate analyses to be related to the weak reaction of TPTD treatment (P < 0.10). In the multiple regression model, postmenopausal women with vitamin K2 supplementation, higher baseline serum 25(OH)D level, and higher PINP concentration at 3 months indicated a good reaction of LS BMD at 12 months (P < 0.05). Patients with gastrointestinal disease, prior bisphosphonate and glucocorticoid treatment, vegetarian diet pattern, and higher baseline BMD were significantly more likely to have a lower absolute LS BMD response compared to patients without these characteristics (P < 0.05). Further analysis confirmed the negative effect of unhealthy lifestyle on TPTD treatment.ConclusionOur results emphasize the significance of a comprehensive assessment of clinical or lifestyle-related characteristics of postmenopausal women with osteoporosis in the management of TPTD therapy in routine care.

Elucidating the low temperature chemistry of o-xylene enhanced by the reaction pool of dimethyl ether

The branched aromatic hydrocarbon with short side chains, such as o-xylene, has weak low temperature oxidation reactivity, while it could proceed low temperature chain recycling reactions by blending a fuel component with higher oxidation reactivity. However, the study of low temperature oxidation kinetics of o-xylene is very scarce. Therefore, this work investigated the low temperature oxidation process of o-xylene in an atmospheric jet stirred reactor by adding a biofuel with higher low temperature oxidation reactivity, i.e. dimethyl ether (DME). A series of characteristic low temperature intermediates, such as phenyl hydroperoxides and ketohydroperoxide from the oxidation of o-xylene, were detected by using the synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). The chemical structures of representative low temperature intermediates were determined by comparing the ionization thresholds from measured photoionization efficiency curves with calculated ionization energies. A kinetic model for o-xylene and DME mixture was developed and verified by literature and present experimental data. Rate of production (ROP) and sensitivity analyses were performed, which indicate that the low temperature oxidation chemistry of o-xylene, such as the negative temperature coefficient behavior, is enhanced by the reaction pool of DME. According to the classical low temperature oxidation mechanism of n-alkanes, the low temperature reactions of o-xylene were proposed. In particular, phenyl hydroperoxides and ketohydroperoxides were revealed to be key indicators for the occurrence of first and second O2 addition reactions during the oxidation of o-xylene, respectively. In addition, the sensitivity analysis uncovers the interaction kinetics between the reaction pools of o-xylene and DME, as well as their effects on fuel consumption and products formation. In summary, present evidence elucidates the low temperature chemistry of a representative branched aromatic, which could contribute to the development of future engines and control of combustion pollutants.

Atomically dispersed Mn–Nx catalysts derived from Mn‐hexamine coordination frameworks for oxygen reduction reaction

AbstractMetal‐organic frameworks recently have been burgeoning and used as precursors to obtain various metal–nitrogen–carbon catalysts for oxygen reduction reaction (ORR). Although rarely studied, Mn–N–C is a promising catalyst for ORR due to its weak Fenton reaction activity and strong graphitization catalysis. Here, we developed a facile strategy for anchoring the atomically dispersed nitrogen‐coordinated single Mn sites on carbon nanosheets (MnNCS) from an Mn‐hexamine coordination framework. The atomically dispersed Mn–N4 sites were dispersed on ultrathin carbon nanosheets with a hierarchically porous structure. The optimized MnNCS displayed an excellent ORR performance in half‐cells (0.89 V vs. reversible hydrogen electrode (RHE) in base and 0.76 V vs. RHE in acid in half‐wave potential) and Zn–air batteries (233 mW cm−2 in peak power density), along with significantly enhanced stability. Density functional theory calculations further corroborated that the Mn–N4–C12 site has favorable adsorption of *OH as the rate‐determining step. These findings demonstrate that the metal‐hexamine coordination framework can be used as a model system for the rational design of highly active atomic metal catalysts for energy applications.

Investigation of human epidermal growth factor receptor 2 expression and its correlation with age, gender, disease stage and degree of tumor differentiation of gastric cancer patients

We performed a comparative observational study to evaluate HER2 protein expression in gastric cancer patients, and explored its correlations with clinicopathological characteristics. HER2 protein expression were assessed in formalin-fixed, paraffin-embedded stomach tissue by immunohistochemistry. Patient information was collected, and associations between clinicopathological factors and HER2 positivity (IHC score 3+ or 2 +) and HER2 negative expression (IHC score 1+or 0) were examined. A total of 109 patients with stomach cancer were included in the study. The level of positivity of Her2 expression, according to the recommendations of the National Comprehensive Cancer Network, in 57 cases (52.3%) showed “no membrane reactivity, in 19 (17.4%) “+” weak membrane reactivity, in 21 (19.3%) “++” cases the reaction was “moderate or lateral membrane and only in 12 cases (11.0%) expression was “+++”, which means “complete basolateral and correlated with various clinical and pathological parameters in patients with gastric cancer: older age, male gender, low-grade tumor. However, we did not find any significant correlation between overexpression of HER2 and tumor localization, histopathological differentiation of the tumor, as well as with the stage of the disease according to TNM.

Suppression of NLRP3 inflammasome orchestrates the protective efficacy of tiron against isoprenaline-induced myocardial injury.

The major contribution of myocardial damage to global mortalities raises debate regarding the exploration of new therapeutic strategies for its treatment. Therefore, our study investigated the counteracting effect of tiron against isoprenaline (ISO)-mediated cardiac infarction in mice. Tiron was administered to mice for 7days prior to two consecutive injections of ISO on days 8 and 9 of the treatment protocol. Tiron significantly reduced the levels of CK-MB, LDH, and AST in serum samples of ISO-challenged mice. A considerable increase in the cardiac antioxidant response was observed in tiron-treated mice, as indicated by depletion of MDA and enhancement of antioxidant activities. Furthermore, tiron induced a marked decrease in NLRP3, ASC, and caspase-1 levels accompanied by weak immune reactions of IL-1β, NF-κB, TLR4, and iNOS in the infarct cardiac tissues. Histopathological screening validated these variations observed in the cardiac specimens. Thus, tiron clearly mitigated the oxidative and inflammatory stress by repressing the NLRP3 inflammasome and the TLR4/NF-κB/iNOS signaling cascade.