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The formation of nitrogen oxides (NO x) during combustion is a topic of substantial fundamental and practical interest, given the complex nature of its formation kinetics and the fact that, as a highly regulated pollutant emission, it is a major constraint in engineering design. To date, there are four known mechanisms by which the strong N–N bond can be broken to facilitate NO x formation from N 2 present in air. Here we posit and explore the possibility of a new NO x formation route mediated by an HNNO intermediate whose reactions with common combustion species break the N–N bond. Altogether, we present results from master equation (ME) calculations for HNNO formation from H + N 2 O (+M), ab initio electronic structure and RRKM/ME calculations for HNNO + O 2 , and simulations of NO profiles in freely propagating flames using a newly constructed HNNO kinetic sub-model. Our ME results for the H + N 2 O reaction indicate that HNNO is the favored product channel at lower temperatures and higher pressures – e.g. favored over all other products up to ∼ 1100 K and over NH + NO up to ∼ 1500 K above 10 atm. Our ab initio electronic structure calculations for trans-HNNO + O 2 show a barrier for abstraction to HO 2 + N 2 O of 18.2 kcal/mol and a barrier for addition of 27.0 kcal/mol to form an HN(OO)NO which can decompose to NO + HNO 2 over a barrier of 32.3 kcal/mol (cis-HNNO + O 2 shows similar reactivity). Altogether, our rate constant calculations and kinetic modeling, which also includes estimated rate constants for HNNO + radical reactions, suggest that HNNO + O 2 mainly recycles HNNO back to N 2 O but is sufficiently slow that the primary fate of HNNO in many combustion situations likely involves reactions with radical species, which appear likely to occur quickly and with high NO x yields. [ABSTRACT FROM AUTHOR]

X-ray fluorescence spectroscopy (XRF) was used to measure temperatures and study mixing, for the first time in silica particle synthesis flames. Hexamethyldisiloxane (HMDSO) and trimethylsilanol (TMSO) were the particle precursors. A multi-element diffusion burner was used to produce a flat methane flame, and the precursors, dilute in inert gas, were injected via a central jet. Krypton was the fluorescent medium at 3.2 % concentration by volume. Scans with Kr in the central flow and not in the main flow were made to assess the mixing effects between the central and main gas flows. When HMDSO or TMSO were added, a secondary diffusion flame formed between the jet and the main methane flame. The results revealed a dramatic change in the centerline temperature profile of the jet gases when HMDSO or TMSO were added. The main methane flame stoichiometry also affected the temperature profiles. The results show HMDSO and TMSO reactions are initiated in a low-temperature and low-oxygen concentration region of the jet where thermal decomposition is not expected to be significant. Reaction of the particle precursors is therefore attributed to radical transport from the main methane flame. In the current work, particle number densities of up to 270 g/m3 locally are estimated. Thus, the study also demonstrates the capability of the XRF technique for high spatial fidelity measurements in flames with high concentrations of condensed-phase particles, leveraging the attribute that the XRF signal is generally not impacted by condensed-phase interferences. The observations and data obtained in this study inform likely reaction pathways for this important class of siloxane compounds. [ABSTRACT FROM AUTHOR]

High-accuracy prediction of activation energies and enthalpies of reaction is theoretically important while computationally challenging for accurately determining the kinetic parameters of chemical reactions in biodiesel combustion. In practice, the Bell-Evans-Polanyi (BEP) correlations between the activation energy and the enthalpy of reaction play an important role in fast estimation with acceptable accuracy. In the present study, the BEP correlations for hydrogen abstraction reactions of biodiesel surrogates by H and OH radicals were theoretically investigated by using high-level orbital-based and ONIOM-based methods. Reaction classes for these reactions were defined based on distinctive electron interactions due to the complex characteristics of esters. Linear BEP correlations were established for each reaction class and validated by the high-level calculations, with deviations being less than 0.90 kcal/mol. The rate constants of some representative hydrogen abstraction reactions were calculated by using the BEP correlations and other approximate theories. These rate constants validate the BEP assumption of similar pre-exponential factors for the reactions in the same group, and they are found to agree reasonably well with the available data in literature. Furthermore, improved predictions to experimental data were obtained by using an existing kinetic model of methyl decanoate oxidation updated with the calculated rate constants. The present BEP correlations are believed to provide effective solutions to some kinetic issues of real biodiesel combustion. [ABSTRACT FROM AUTHOR]

Abstract Cavity-enhanced absorption spectroscopy (CEAS) has generated much interest in shocktube kinetics studies because of its recent success in achieving improved sensitivity and high time resolution with robust optical alignment. While recent progress demonstrated experimental schemes including off-axis scanned-wavelength approach and on-axis ps-pulsed laser approach, that both successfully suppressed the laser-cavity coupling noise, this paper develops a theoretical model to predict the CEAS sensor performance that can be used as a design tool applicable to more generalized cases. The method models the optical field in the cavity based on the decentered Gaussian beam model, from which the cavity transmission spectrum and the laser-cavity coupling noise can be numerically calculated. The simulation results predict sensor performance for different cavity configurations and laser characteristics, including various degrees of laser-cavity mode-matching, laser linewidths, scanning rates, and cavity filling conditions. Simulation with example wavelengths in the ultraviolet, near-infrared, and mid-infrared showed increasing mode-matched beam waist size for increasing wavelengths. An off-axis alignment scheme was found to be capable of suppressing the coupling noise by two orders-of-magnitude at a moderate laser linewidth of 1 GHz. Coupling noise level on the order of 1e-5 for scanned-wavelength off-axis alignment case with a narrowband mid-infrared laser was obtained by model calculation and agreed with experimental results within acceptable uncertainty range. The developed method can serve to guide future design and optimization of CEAS system in shocktube studies. [ABSTRACT FROM AUTHOR]

Abstract Theoratical studies on the chemistry of methyl acetate radicals with molecular oxygen was conducted to get further understanding of biodiesel combustion. Reactions of the first oxygen addition to methyl acetate radicals has been investigated by high level quantum chemical methods, and rate constants were computed by using microcanonical variational transition state theory coupled with Rice–Ramsberger–Kassel–Marcus/Master-Equation theory. The calculated rate constants agree reasonably well with both theoretical and experimental results of chain-like alkoxy radicals. We considered each step in the oxidation process as a class of reaction, including all the possible reactions taking place, only the formation and re-dissociation of initial adducts are critical for the low temperature combustion of methyl acetate. The current study is an extension of kinetic data for such chain propagation reactions for methyl acetate oxidation in a wider pressure and temperature range, which can be used for the modeling study of low temperature oxidation of methyl esters. [ABSTRACT FROM AUTHOR]

Flat flame burners are valuable tools for studying complex combustion phenomena like particle synthesis due to the well-controlled and well-behaved initial and boundary conditions. In this study, the methane/air flame temperature and tracer density profiles of a multi-element diffusion burner equipped with a central tube were characterized using krypton (Kr) x-ray fluorescence at the Advanced Photon Source at Argonne National Laboratory. The experiments were performed using a fuel-to-oxygen equivalence ratio of 0.8 and 3.3% Kr by volume was added to the reactant gases. One- and two-dimensional scans of non-combusting (i.e., cold flow) and combusting conditions, both with and without flow through the central tube were performed. Spatially-resolved Kr number density profiles were obtained at different planar locations and heights above the surface of the burner. The results show rapid mixing occurred near the exit-plane of the burner and increased spatial uniformity was achieved from 0.1 mm to 0.5 mm above the surface of the burner. The data also showed the impact of the central tube flow on the main methane/air flame, including evidence of the central tube flow mixing with the main flow. Flame temperatures were calculated from the fluorescence measurements at various heights above the burner surface and were in good agreement with model predictions for a burner stabilized flame. These high-fidelity measurements provide accurate baseline data that are particularly valuable for understanding the effects of fuel and air mixing on downstream phenomena, such as the formation of condensed-phase products. [ABSTRACT FROM AUTHOR]

Effective communication is essential for nursing students to provide safe patient care. Many communication consensuses focus on physician-associated communication rather than nurses' interpersonal communication. However, studies on developing a systematic and comprehensive communication knowledge system for nursing students are scarce. To explore the teaching content and teaching framework of nurses' interpersonal communication, construct a systematic and scientific knowledge system for interpersonal communication among nursing students and provide a theoretical basis for the training of nurses on interpersonal communication. Based on the literature review and comparative research, this study explored the theoretical basis and basic principles of constructing an interpersonal communication knowledge system for nurses. Moreover, a correspondence questionnaire on nurses' interpersonal communication knowledge systems was initially constructed to clarify the related teaching content and structure. Finally, the Delphi method was used to establish the index of the nurses' interpersonal communication knowledge system according to the principle of expert selection and inclusion criteria. The Delphi method included 26 experts from nursing education, clinical nursing, nursing management and other fields for consultation. The effective response rate of the letter inquiry was 96.3 % in the first round and 100 % in the second round. The judgment basis, familiarity and authority coefficient of expert consultation were 0.907, 0.862 and 0.884, respectively. In the two rounds of inquiry, the coordination coefficients of the total questionnaire were 0.228 and 0.302, which was statistically significant (P < 0.001). Thereafter, a wheeled model of nurses' interpersonal communication knowledge system with 3 primary indicators, 13 secondary indicators and 58 tertiary indicators was constructed, which included professional ethics and attitude, communication knowledge and communication skills. Literature and comparative research methods along with Delphi expert consultation were used to construct a scientific and systematic knowledge system of nurses' interpersonal communication. The research methods were feasible, and the results were scientific and reliable, thereby providing a basis for the education of nurses' interpersonal communication among nurses and the compilation of related teaching materials in China and globally. Furthermore, special attention should be paid to the comprehensive cultivation of nursing students' professional ethics and attitude, communication knowledge and communication skills. [ABSTRACT FROM AUTHOR]

Estrogen, via its binding to the estrogen receptor (ER), plays an important role in breast cancer cell proliferation and tumor development. Indole-3-carbinol (I3C), a compound occurring naturally in cruciferous vegetables, exhibits a potent antitumor activity via its regulation of estrogen activity and metabolism. This study was designed to determine the effect of I3C on the potential to inhibit the ER-alpha. Using a reporter gene driven by the estrogen receptor, I3C (10-125 micromol/L) significantly repressed the 17ss-estradiol (E2)-activated ER-alpha signaling in a dose-dependent manner. I3C and breast cancer susceptibility gene 1 (BRCA1) synergistically inhibited transcriptional activity of ER-alpha. Moreover, I3C down-regulated the expression of the estrogen-responsive genes, pS2 and cathepsin-D, and up-regulated BRCA1. The inhibitory effects of I3C did not contribute to its cytotoxic effects because these activities were observed at less than toxic concentrations. These results further suggest that antitumor activities of I3C are associated not only with its regulation of estrogen activity and metabolism, but also its modulation of ER transcription activity. [ABSTRACT FROM AUTHOR]

• Specific reaction mechanism for the catalytic pyrolysis of MA was proposed firstly. • Identified the source of the intermediate ketene, dominating the selectivity of products. • Provides new insights into the catalytic combustion of biodiesels and VOC controlling. The catalytic chemistry of methyl acetate (MA) over zeolites was investigated theoretically at the M06-2X/6–311++G(d,p) level, and its chemical reaction rate constants were calculated by using the transition state theory. With particular interest in looking for feasible reactions of the protolytic cracking channels, the present study reveals that the ketene formation in the concerted mechanism and that of acetyloxy + CH 3 are competitive reactions during MA consumption. Furthermore, comparisons between the catalytic and conventional pyrolysis of MA were carried out to demonstrate the benefits of introducing the catalysts to MA combustion. It is demonstrated that the energy barriers of the dissociation reactions for MA over H-ZSM-5 zeolites decrease significantly compared with the conventional pyrolysis of MA. Changes of production distributions were also observed between the catalytic pyrolysis and the conventional pyrolysis. The results also provides new insight into the mechanism of the MA catalytic pyrolysis that will guide the improvements in the engine combustion efficiency and in the control of volatile organic compounds, and will also help to improve the selectivity of the conversion of methanol to hydrocarbon and olefin products. [ABSTRACT FROM AUTHOR]

• The overall rate constant was aggravated due to the presence of armchair site. • OH attacking should preferentially occur at the free-edge site. • Subsequent step of O 2 attacking should favor the armchair-edge site. • Providing new kinetics and thermodynamics data for OH-initiated oxidative degradation mechanism. To get a better understanding of oxidative degradation of polycyclic aromatic hydrocarbons (PAH) in the atmospheric and combustion chemistry, benzo[ ghi ]perylene (BP) was selected as their prototype to be investigated by combining ab initio electronic structure theory calculations (M06-2X/6-31G(d,p)) and the conventional transition state theory. For BP-OH adducts, O 2 addition favored the armchair edge comparing with the free and zigzag ones. The overall rate constant was increased due to the presence of armchair site; and thereby it has a prompt effect on the oxidation reactivity. This implies that given an arbitrary shaped PAH, OH attack preferentially occurs at the free-edge sites and subsequent O 2 attack favors the armchair-edge sites. Morever, the current study provides new kinetics and thermodynamics data for OH-initiated oxidative degradation mechanism of benzo[ ghi ]perylene in a wider temperature range, which can be used for modeling the fate of large PAHs during combustion and in the atmosphere. [ABSTRACT FROM AUTHOR]

Achieving minimal levels of nitrogen oxides (NO x) during combustion is a major constraint in the design of advanced high-efficiency engines. NO x can be formed during combustion of any fuel—including those without fuel-bound nitrogen—in air, where radicals can attack molecular nitrogen (N 2) present in air to break the strong N N bond to ultimately form NO x. Paramount to the goal of minimizing NO x formation is knowledge of the fundamental routes by which the strong N N bond in N 2 can be broken. Historically, there have been four known routes for breaking the strong N N bond in N 2 to ultimately form NO x. We have recently posited that another route—mediated by an HNNO intermediate—may also play a role, particularly at the high pressures and low peak temperatures relevant to high-efficiency, low-NO x engines. Our previous theoretical and modeling studies show HNNO to be a major product of the N 2 O + H reaction at high pressures and low temperatures; once formed, HNNO is likely to react with radicals in barrierless reactions that would occur quickly and with high NO x yields. In the present paper, we report measurements of H 2 , O 2 , H 2 O, N 2 O, NO, NO x , and NH 3 in jet-stirred reactor experiments for an H 2 /O 2 /N 2 O/NO/N 2 /Ar mixture that specifically target HNNO pathways. Importantly, we observe significant formation of NO and NH 3 —both of which provide signatures of the HNNO mechanism that are not predicted by previous models without it. Flame simulations using a new sub-model describing pressure-dependent formation and consumption of HNNO show these pathways to be among the most prominent formation routes at high pressures and low peak temperatures. However, exact quantification of the role of HNNO in NO x formation and quantitative predictions of NO x in general require more accurate rate constants for both HNNO pathways and mixture rules for pressure-dependent reactions. [ABSTRACT FROM AUTHOR]

The N 2 O + O reaction plays a critical role in NO x formation at high pressures and low peak temperatures, in the "dark zone" region of deflagration waves of organic energetic materials, and in N 2 O consumption in NH 3 combustion. While the rate constant for N 2 O + O = NO + NO (R3) is considered reasonably well established, viewpoints regarding the rate constants for N 2 O + O = N 2 + O 2 (R2)—and even the main products of the N 2 O + O reaction—have not reached a consensus, with studies from the past few years continuing to reach drastically different conclusions. To date, no single model has been presented that can reproduce all key datasets on both sides of the debate. Using the MultiScale Informatics (MSI) approach, we identified a model consistent with a vast catalog of theoretical and experimental data previously used to determine rate constants for R2, R3, and other key reactions influencing experimental interpretations. Notably, this MSI model (presented herein) reproduces all experimental datasets previously used to anchor low-activation-energy k 2 expressions that greatly favor R2 at intermediate temperatures. However, its kinetic parameters are also consistent with theoretical calculations that instead show high activation energy for R2 and k 2 values many orders of magnitude lower—such that R3 is the main channel at essentially all temperatures. This model is also consistent with our new experimental data (presented in our companion paper) at optimally selected conditions that avoid the interpretation ambiguities that have hindered definitive conclusions from previous experimental data. The present analysis elucidates the role of secondary reactions that would have artificially inflated the apparent k 2 / k 3 ratio previously deduced from experiments in a manner that may not have been detectable from even multi-species measurements at typical conditions—and may, therefore, explain the persistent historical difficulties in establishing the main products of N 2 O + O. Novelty and significance statement Despite decades of research, viewpoints regarding the rate constants for N 2 O + O = N 2 + O 2 (R2)—and even the main products of the N 2 O + O reaction—have not reached a consensus, with studies from the past few years still reaching drastically different conclusions. To date, no single model has been presented that can reproduce all key datasets on both sides of the debate. Here, we present a single model consistent with a vast catalog of theoretical and experimental data, including all experimental datasets previously used to anchor low-activation-energy expressions for k 2 that greatly favor R2 as the main channel at intermediate temperatures—but with kinetic parameters consistent with theoretical calculations that instead show high activation energy for R2 and N 2 O + O = NO + NO (R3) as the main channel at essentially all temperatures. [ABSTRACT FROM AUTHOR]

Dietary education and modification interventions are valuable and feasible strategies for enhancing nutritional status and managing symptoms in patients with gastric cancer following gastrectomy. In alignment with administrative policies prioritizing shorter hospital stays and enhanced postoperative self-management, the provision of a simplified nutritional management approach following gastrectomy holds promise for preventing weight loss and expanding resources for monitoring both the nutritional and symptomatic aspects of these patients. This study evaluated the effectiveness of an integrative approach involving the five sequential steps of Conversation, Assessment, Nutrition plan, Complications, Evaluation, and Reassurance or Removal (CANCER) into Altering Intake and Managing Symptoms (AIMS), with specific focus on enhancing nutritional status and symptom management. A single-blind, two-arm, randomized controlled trial. This study was conducted at a tertiary hospital in Shandong province, China. Patients with total or subtotal gastrectomy for gastric cancer. The participants were randomly assigned to either the intervention or control group in a 1:1 ratio. The intervention group received a 16-week CANCER-AIMS intervention program. The control group received usual routine care dietary guidance. Questionnaires and electronic medical records of each patient were used to assess dietary intake, dietary symptoms, and subjective and objective nutritional status. Outcomes were assessed at four specific time points: the day before discharge and at 4-, 8-, and 16-weeks following hospital discharge. Thirty-eight participants completed the study. The findings revealed significant interaction effects between group and time for dietary intake, dietary symptoms, and nutritional status between intervention and control groups (P < 0.001). The intervention group had significantly higher dietary intake, fewer dietary symptoms, and better nutritional status post-intervention than the control group (P < 0.001). Moreover, there were significant differences in dietary intake, dietary symptoms, and nutritional status according to time in both the intervention and control groups. The CANCER-AIMS intervention for patients with gastric cancer following gastrectomy may be efficient at enhancing nutritional intake, reducing negative dietary symptoms, and thus improving both their subjective and objective nutritional status. [ABSTRACT FROM AUTHOR]

Abstract: Eight compounds (1-7b) were isolated from the aerial parts of S. halepense in present investigation and five of them (2, 5, 6, 7a, 7b) were firstly reported from this species. The two rare diastereomeric flavonolignans tricin-4''-O-(threo-β-guaiacylglyceryl) ether and tricin-4''-O-(erythro-β-guaiacylglyceryl) ether is from Sorghum genus for the first time. The chemotaxonomic significance of these compounds was summarized. [Copyright &y& Elsevier]

n-Heptane, as an alternative gasoline fuel, was used for research on low-temperature oxidation in this study, where the reactions of alkyl radicals (C 7 H 15) and O 2 play an important role. The related chemical reaction kinetics on four C 7 H 15 radicals and O 2 were investigated. The potential energy surfaces (PESs) of C 7 H 15 O 2 were obtained by the quantum chemical calculation method of CBS-QB3. The pressure- and temperature- dependence of the rate constants was also calculated by solving master equations based on Rice–Ramsperger–Kassel–Marcus theory. In this work, all possible reaction pathways in the oxidation process were considered and calculated. Formation, concerted elimination, and intramolecular H atom transfer reactions of initial product RO 2 are very critical to the low-temperature combustion. For four C 7 H 15 radicals, the energy barriers that form RO 2 from the HR + O 2 association are typically zero, and barriers to subsequent reactions are different by up to 30 kcal/mol. It is most advantageous to form QOOH from RO 2 through a six- or seven-member ring transition state. In terms of kinetic aspect, compared with the reaction of O 2 plus secondary radicals (HR2, HR3, HR4), the reaction of adding O 2 to primary radical (HR1) is less competitive at low temperatures. Moreover, the kinetic data obtained in this study will play an important role in the kinetic model of low-temperature combustion for n-heptane. [ABSTRACT FROM AUTHOR]

Abstract Reactions between chlorine and unsaturated esters in gas phase are examined in a slow-flow reaction tube inside the laboratory-built photoionization mass spectrometer at the energy range of 8–11 eV. 248 nm laser radiation is used to initiate the reaction. Products are distinguished, C 5 H 8 O 2 Cl for addition, and C 5 H 7 O 2 , C 5 H 7 O 2 Cl and C 5 H 9 O 2 Cl for abstraction. The direct or indirect products are detected, indicating secondary reactions. And experimental ionization potentials are procured for direct adducts of methyl methacrylate to be 8.30 eV and for that of ethyl acrylate to be 9.95 eV which are well consistent with theoretical ionization potentials of likely isomers. Theoretical reaction channels are also accounted for, optimized under M06-2X/6-31 + G(d,p) level and ionization potentials of products are calculated under M06-2X/6-31 + G(d,p) level also. Differences between experimental and theoretical details are discussed. Highlights • Direct adducts from acrylate esters and chlorine atom are detected. • Mass spectra show fragments from direct adducts. • Addition and abstraction coexist in the potential energy surfaces. • Difference of ionized and neutral state indicates difficulty of adiabatic ionization. [ABSTRACT FROM AUTHOR]

The pyrolysis of methyl decanoate (MD), an ideal surrogate of biodiesels, was investigated in a flow reactor at the pressures of 30 and 760 Torr and the temperature ranging from 773 to 1198 K. A great variety of pyrolysis products including free radicals, n-alkanes, 1-alkenes, alkynes, unsaturated esters and aromatics were comprehensively observed and identified by employing synchrotron vacuum ultraviolet photoionization mass spectrometry. A new kinetic model for MD pyrolysis was constructed and applied to validate the experimental data. Modeling analyses involving rate of production analysis and sensitivity analysis were performed to help explore the pyrolysis kinetics of MD and the formation mechanisms of key species. The analysis results show that the decomposition of MD is determined by the H-abstraction and unimolecular dissociation reactions during the whole pyrolysis process, whereas the contributions of H-abstraction reactions are enhanced as the pressure elevates. C 4 -C 9 unsaturated esters are principally yielded from the β -scission of ester radicals; while the β -scission reactions of MD radicals are responsible for the formation of C 5 -C 9 1-alkenes. In addition, 1-alkenes can be further decomposed to form small radicals and molecules. Through the combination reactions such as the reaction routes of C 3  + C 3 , C 4  + C 2 and C 5  + C 2 , these radicals and molecules can be transformed into benzene and benzyl radical, which are demonstrated as the crucial precursors of polycyclic aromatic hydrocarbons. In conclusion, the pyrolysis of MD would not only significantly enhance the cognitions of various pollutant formation mechanisms but also have a guiding significance for the combustion in the fuel-cooled engine. [ABSTRACT FROM AUTHOR]

The objective of this study is to explore the unsteady cavitation characteristics and the mechanism of cavitation-vortex interaction around a twist hydrofoil. The cavitation conditions were simulated using the Partially-Averaged Navier-Stokes (PANS) method in conjunction with a homogeneous flow cavitation model. The numerical method employed in this study successfully captures the intricate shedding process of cavitation on the hydrofoil surface. Furthermore, the cavity morphology obtained at various time instants exhibits a remarkable agreement with the experimental results. The simulation results of the unsteady characteristics of cavitation shedding on the hydrofoil surface revealed that the shedding process could be divided into primary and secondary shedding phases. The primary shedding happened as a result of the re-entrant jet flow generated by the adverse pressure gradient at the cavitation tail. Notably, the secondary shedding was predominantly caused by the combined effects of the re-entrant jet and the side re-entrant jet flow. During the primary shedding process, the cavitation experienced disturbances from the side re-entrant jets, causing it to roll and be drawn upwards into a U -shape cavity structure. Subsequently, as the secondary shedding happened, the side re-entrant jets contributed to the formation of a secondary U -shape cavity at the cavitation tail. The investigation on the cavitation-vortex interaction around the hydrofoil showed a strong consistency between the distribution of vortices and cavitation. The foot of the primary U -shape vortex was attached to the hydrofoil surface, while the shedding vortex tail on both sides exhibited secondary U -shape vortex structures. The primary U -shape vortex formation resulted from the combined effects of suction and rotation generated by the side re-entrant jets and re-entrant jets on both sides of the hydrofoil. The secondary U -shape vortex was induced by secondary shedding cavitation which produced by rotational effects at the stable cavitation tail. • The Partially-Averaged Navier-Stokes method combined with Zwart cavitation model is used to simulate cavitation flow around the hydrofoil. • The unsteady characteristics of the cavitation shedding on the twisted hydrofoil surface are investigated. • The vortex-cavitation interference and cavitation-induced vortex structures are investigated based on the Q criterion. • The production mechanism of secondary U -shape vortex is elucidated. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions from manure management are an environmental concern that hinders the livestock industry. Methane (CH 4 ) is the primary non-CO 2 GHG emitted from outdoor manure storage facilities. Understanding the relationship between the microbial community and manure physicochemical characteristics, together with their contributions to CH 4 emission during storage are of importance for mitigation and ecological significance. In this study, the archaeal and bacterial communities in manure were investigated using high-throughput sequencing, revealing that manure physicochemical characteristics have a major influence on the distribution and enrichment of methanogenic taxa as well as CH 4 emission. Moisture and total phosphorus (TP) were positively correlated with Methanocorpusculum abundance in cow manure with high CH 4 emission, while they were negatively correlated with Methanobacterium abundance in heifer manure with low CH 4 emission at the species level. Quantitative PCR analysis of transcript abundance of alpha subunit of Methyl coenzyme-M reductase (mcrA) gene in cow manure disclosed relatively strong activity of Methanocorpusculum . sPLS regression and network analyses of microbial taxa revealed that different bacteria–methanogen patterns are associated with CH 4 emission. Our data indicates that the manure physicochemical characteristics influence CH 4 emissions by altering the divergence of methanogens that differ in transcriptional efficiency of mcrA gene and are correlated with some bacterial taxa, providing insights into the mechanisms of CH 4 emission during manure storage. [ABSTRACT FROM AUTHOR]

In ischemia-reperfusion stroke, microglia play a dual role in brain injury as well as brain repair, and promoting their switch from a pro-inflammatory M1 phenotype to an anti-inflammatory M2 phenotype is considered to be a potential therapeutic strategy. Docosahexaenoic acid (DHA) is an essential long-chain omega-3 polyunsaturated fatty acid that exhibits potent anti-inflammatory properties in the acute phase of ischemic stroke, but its effect on microglia polarization is unknown. Thus, the objective of this study was to investigate the neuroprotective effects of DHA on rat brain following ischemia-reperfusion injury, and to investigate the mechanism by which DHA regulates microglia polarization. We administered DHA 5 mg/kg intraperitoneally daily for 3 d following a transient middle cerebral artery occlusion reperfusion model in rats. The protective effects of DHA on cerebral ischemia-reperfusion injury were detected by TTC staining, HE staining, Nissler staining, and TUNEL staining. Quantitative real-time PCR, immunofluorescence, western blot, and enzyme-linked immunosorbent assay were used to detect the expression of M1 and M2 microglia-associated markers and PPARγ-mediated ERK/AKT signaling pathway proteins. We found that DHA significantly improved brain injury by decreasing the expression of the M1 phenotypic marker (iNOS, CD16) and increasing the expression of the M2 phenotypic marker (Arg-1, CD206). DHA also increased the expression of peroxisome proliferator-activated receptor gamma (PPARγ) mRNA and protein, increased the expression of the pathway protein AKT, and decreased the expression of ERK1/2. In addition, DHA promoted the expression of anti-inflammatory factor IL-10 and decreased the expression of pro-inflammatory factors TNF-α and IL-1β. However, the PPARγ antagonist GW9662 greatly blocked these beneficial effects. These results suggest that DHA may activate PPARγ to inhibit ERK and activate AKT signaling pathways to regulate microglia polarization, thereby reducing neuroinflammation and promoting neurological recovery to alleviate cerebral ischemia-reperfusion injury. • Cerebral ischemia-reperfusion injury may result in neuronal death and neurological impairment. • Modulation microglia polarization to reduce brain injury is considered a potential therapeutic strategy for ischemic stroke. • DHA may regulate microglia polarization by activating PPARγ to inhibit ERK and activate AKT signaling pathways. • DHA can reduce neuroinflammation and promote neurological recovery to alleviate cerebral ischemia-reperfusion injury. [ABSTRACT FROM AUTHOR]

• Presented a method to derive subgrade modulus consistent with ground deformation. • Proposed solutions for radial modulus considering the influence of the grout layer. • Ground deformation would lead to a nonuniformly distributed subgrade modulus. Subgrade modulus is a critical parameter when analyzing the segmental lining of shield tunnels. However, prevailing analytical solutions of radial subgrade modulus (k r) are based on predefined ideal deformation modes, either circular or oval, which are not consistent with the actual ground deformation, and the influence of the grout layer is commonly neglected. In view of this, this study presents a solution of k r considering the actual deformation of the ground and the grout layer between linings and surrounding ground. A displacement fitting method is proposed to relate k r to the arbitrary distribution shape of ground deformation. With this method, k r for actual deformation consists of a series of radial subgrade moduli (k r m) for single deformation modes described by sine and cosine functions. Theoretical solutions of k r m considering the influence of the grout layer for single deformation modes are then derived based on the composed ground which is made up of the ground and the grout layer. The influence of the grout layer on k r m is then discussed by a parameter study. Moreover, the applicability of the proposed method is illustrated through a design case, where the calculated internal forces agree well with the data from field measurement. The influence of actual ground deformation and grout layer on k r , internal forces, and displacement of shield tunnel is then discussed. Results show that an accurate prediction of k r requires the consideration of the actual deformation of the lining and the influence of the grout layer. [ABSTRACT FROM AUTHOR]

Abstract: The aim was to examine early event-related potential (ERP) changes during mental arithmetic calculation task in mild cognitive impairment patients compared to healthy elderly. 16 mild cognitive impairment (MCI) subjects and 16 healthy Chinese older adults were studied. Event-related potentials were elicited using a simple mental calculation task. Performance on arithmetic calculation task, and the latency and amplitude of early event-related potential components (N1, P1, N170, and P2) were compared between the two groups. The reaction time of MCI group was significantly longer than that of control group (1691.03±94.59 vs. 1539.55±27.76, P <0.01). The correct rate of MCI group (0.9463±0.04) was significantly lower than that of control group (0.9776±0.02, P <0.01). The latency of temporal–occipital N170 and central–prefrontal P2 of MCI group were significantly prolonged compared to controls. MCI subjects presented significantly higher P2 amplitude. Compared with healthy controls, N170 was significantly lower at left temporal–occipital region and higher at right temporal–occipital region in mild cognitive impairment. Mild cognitive impairment patients had deficit on simple calculation. The early arithmetic calculation processing mechanism of mild cognitive impairment patients may be different from normal people. [Copyright &y& Elsevier]