43 research outputs found

    Projecting meat and cereals demand for China based on a meta-analysis of income elasticities

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    There are many projections for China's food demand, and the projection results differ significantly from each other. Different values for income elasticities could be a major reason. This study projects meat and cereals demand for China based on a meta-analysis of the income elasticity estimates using a collection of 143 and 240 income elasticity estimates for cereals and meat products, respectively, from 36 primary studies. We find that income elasticities for most cereals (general cereals, rice, and coarse grains) and all meat products (general meat, pork, poultry, beef & mutton) tend to decline as per capita income increases, except for wheat, which increases. Taking this into account, differences between consumption projections based on time-varying income elasticities and values based on constant elasticities are substantial in quantities and increase over time

    Soil diazotrophic abundance, diversity, and community assembly mechanisms significantly differ between glacier riparian wetlands and their adjacent alpine meadows

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    Global warming can trigger dramatic glacier area shrinkage and change the flux of glacial runoff, leading to the expansion and subsequent retreat of riparian wetlands. This elicits the interconversion of riparian wetlands and their adjacent ecosystems (e.g., alpine meadows), probably significantly impacting ecosystem nitrogen input by changing soil diazotrophic communities. However, the soil diazotrophic community differences between glacial riparian wetlands and their adjacent ecosystems remain largely unexplored. Here, soils were collected from riparian wetlands and their adjacent alpine meadows at six locations from glacier foreland to lake mouth along a typical Tibetan glacial river in the Namtso watershed. The abundance and diversity of soil diazotrophs were determined by real-time PCR and amplicon sequencing based on nifH gene. The soil diazotrophic community assembly mechanisms were analyzed via iCAMP, a recently developed null model-based method. The results showed that compared with the riparian wetlands, the abundance and diversity of the diazotrophs in the alpine meadow soils significantly decreased. The soil diazotrophic community profiles also significantly differed between the riparian wetlands and alpine meadows. For example, compared with the alpine meadows, the relative abundance of chemoheterotrophic and sulfate-respiration diazotrophs was significantly higher in the riparian wetland soils. In contrast, the diazotrophs related to ureolysis, photoautotrophy, and denitrification were significantly enriched in the alpine meadow soils. The iCAMP analysis showed that the assembly of soil diazotrophic community was mainly controlled by drift and dispersal limitation. Compared with the riparian wetlands, the assembly of the alpine meadow soil diazotrophic community was more affected by dispersal limitation and homogeneous selection. These findings suggest that the conversion of riparian wetlands and alpine meadows can significantly alter soil diazotrophic community and probably the ecosystem nitrogen input mechanisms, highlighting the enormous effects of climate change on alpine ecosystems

    Comparison of thoracoabdominal versus abdominal-transhiatal surgical approaches in Siewert type II adenocarcinoma at the esophagogastric junction: Protocol for a prospective multicenter randomized controlled trial

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    BackgroundSiewert type II adenocarcinoma of the esophagogastric junction (Siewert II AEG) can be resected by the right thoracoabdominal surgical approach (RTA) or abdominal-transhiatal surgical approach (TH) under minimally invasive conditions. Although both surgical methods achieve complete tumor resection, there is a debate as to whether the former method is superior to or at least noninferior to the latter in terms of surgical safety. Currently, a small number of retrospective studies have compared the two surgical approaches, with inconclusive results. As such, a prospective multicenter randomized controlled trial is necessary to validate the value of RTA (Ivor-Lewis) compared to TH.MethodsThe planned study is a prospective, multicenter, randomized clinical trial. Patients (n=212) with Siewert II AEG that could be resected by either of the above two surgical approaches will be included in this trial and randomized to the RTA group (n=106) or the TH group (n=106). The primary outcome will be 3-year disease-free survival (DFS). The secondary outcomes will include 5-year overall survival (OS), incidence of postoperative complications, postoperative mortality, local recurrence rate, number and location of removed lymph nodes, quality of life (QOL), surgical Apgar score, and duration of the operation. Follow-ups are scheduled every three months for the first 3 years after the surgery and every six months for the next 2 years.DiscussionAmong Siewert II AEG patients with resectable tumors, this is the first prospective, randomized clinical trial comparing the surgical safety of minimally invasive RTA and TH. RTA is hypothesized to provide better digestive tract reconstruction and dissection of mediastinal lymph nodes while maintaining a high quality of life and good postoperative outcome. Moreover, this trial will provide a high level of evidence for the choice of surgical procedures for Siewert II AEG.Clinical trial registrationChinese Ethics Committee of Registering Clinical Trials, identifier (ChiECRCT20210635); Clinical Trial.gov, identifier (NCT05356520)

    Comparison of primary and metastatic site‐related PD‐L1 expression in predicting ORR in patients with advanced NSCLC who received ICB‐based therapy

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    Abstract Background Whether the value of PD‐L1 expression from metastatic sites to predict the efficacy of immune checkpoint blockade (ICB)‐based treatment is equivalent to that from a primary tumor is uncertain. This study aimed to compare the utility of PD‐L1 TPS from a primary lung tumor and metastatic sites to predict the overall response rate (ORR) of first‐line ICB‐based treatment. Methods This study included 249 patients with advanced non‐small cell lung cancer (NSCLC) who received first‐line ICB‐based treatment. All subjects underwent PD‐L1 testing prior to ICB‐based treatment and were divided into two cohorts corresponding to the different biopsy sites: lung primary site‐sampled cohort (PT cohort, n = 167) and metastatic site‐sampled cohort (MT cohort, n = 82). Results There was no statistical significance in PD‐L1 TPS distribution between the two cohorts (p = 0.742). PD‐L1 TPS ≥50% was also related to high ORR compared with PD‐L1 < 50% in the PT cohort (34.3% vs. 14.1%, p = 0.004). In contrast, ICB‐based therapy could bring comparable ORR (35.1% vs. 33.3%, p = 0.871) in the MT cohort regardless of PD‐L1 TPS status (≥50%, or <50%). As supported, when the cutoff value of TPS was selected as 50%, it was suggested that PT‐related PD‐L1 was the independent predictor of ORR (OR 2.870, 95% CI: 1.231–6.694, p = 0.015) rather than MT‐related PD‐L1 (OR 0.689, 95% CI: 0.236–2.013, p = 0.495). Furthermore, ROC proved that PT‐related PD‐L1 expression manifested a better AUC of 0.621 (p = 0.026) than that of MT‐related PD‐L1 (AUC = 0.565, p = 0.362). Conclusion Compared with PT‐related PD‐L1 expression, MT‐related PD‐L1 expression showed limited value in predicting ORR in patients with advanced NSCLC receiving ICB‐based therapy. It was concluded that even patients with low MT‐related PD‐L1 expression could benefit from ICB‐based therapy

    Reaction Mechanism of Ethylene Aromatization over HZSM-5 Zeolite: From C4 to C6 Intermediates

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    The ONIOM2 (B3LYP/6-31G(d,p):UFF) method based on the 78T cluster model was used to study the reaction mechanism of C4 to C6 intermediates during the ethylene aromatization over HZSM-5 zeolite. The catalytic mechanism of acidic zeolite and the effect of zeolite pore size on the shape selectivity for the products was discussed. The results indicated that the n-butoxide, which is the intermediate product of ethylene dimmerization, reacted with ethylene to form n-hexane alkoxide, but it was difficult to carry out further cyclization because of the restriction of the pore size of ZSM-5 zeolite. However, along the stepwise pathways, n-butoxide was transformed into n-butene through deprontonation and then reacted with ethylene to form 3-methylpentane alkoxide intermediate, which then formed methylcyclopentane through cyclization and deprotonation. The methylcyclopentane released a hydrogen molecule by the aid of zeolite acidic proton and formed the unstable methyl-cyclopentane carbonium, which then generated the cyclohexane carbonium through reconfiguration. The calculated activation energy was 158.42 kJ/mol for n-butoxide deprontonation, 130.71 kJ/mol for the oligomerization of 1-butene and ethylene, and 122.06 kJ/mol for the cyclization of 3-methylpentane alkoxide. As a result of the confinement of zeolite pore, the five-member ringed methylcyclopentane was formed as a crucial intermediate

    Projecting Meat and Cereals Demand for China Based on a Meta-Analysis of Income Elasticities

    No full text
    There are many projections for China’s food demand, and the projection results differ significantly from each other. Different values for income elasticities could be a major reason. This study projects meat and cereals demand for China based on a meta-analysis of the income elasticity estimates using a collection of 143 and 240 income elasticity estimates for cereals and meat products, respectively, from 36 primary studies. We find that income elasticities for most cereals (general cereals, rice, and coarse grains) and all meat products (general meat, pork, poultry, beef & mutton) tend to decline as per capita income increases, except for wheat, which increases. Taking this into account, differences between consumption projections based on time-varying income elasticities and values based on constant elasticities are substantial in quantities and increase over time

    Applicability of the low-grade inflammation score in predicting 90-day functional outcomes after acute ischemic stroke

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    Abstract Background and purpose The low-grade inflammation (LGI) score, a novel indicator of chronic LGI, combines C-reactive protein (CRP), leukocyte counts, the neutrophil/lymphocyte ratio (NLR), and the platelet (PLT) count to predict outcomes of patients with various conditions, such as cardiovascular diseases, cancers, and neurodegenerative diseases. However, few studies have examined the role of the LGI score in predicting functional outcomes of patients with ischemic stroke. The present study aimed to evaluate the association between the LGI score and functional outcomes of patients with ischemic stroke. Methods A total of 1,215 patients were screened in the present study, and 876 patients were finally included in this retrospective observational study based on the inclusion and exclusion criteria. Blood tests were conducted within 24 h of admission. Severity of ischemic stroke was assessed using the NIHSS score with severe stroke denoted by NIHSS > 5. Early neurological deterioration (END) was defined as an increment in the total NIHSS score of ≥ 2 points within 7 days after admission. Patient outcomes were assessed on day 90 after stroke onset using the modified Rankin Scale (mRS). Results The LGI score was positively correlated with baseline and the day 7 NIHSS scores (R2 = 0.119, p < 0.001;R2 = 0.123, p < 0.001). Multivariate regression analysis showed that the LGI score was an independent predictor of stroke severity and END. In the crude model, the LGI score in the fourth quartile was associated with a higher risk of poor outcomes on day 90 compared with the LGI score in the first quartile (OR = 5.02, 95% CI: 3.09–8.14, p for trend < 0.001). After adjusting for potential confounders, the LGI score in the fourth quartile was independently associated with poor outcomes on day 90 (OR = 2.65, 95% CI: 1.47–4.76, p for trend = 0.001). Finally, the ROC curve analysis showed an AUC of 0.682 for poor outcomes on day 90 after stroke onset. Conclusion The LGI score is strongly correlated with the severity of acute ischemic stroke and that the LGI score might be a good predictor for poor outcomes on day 90 in patients with acute ischemic stroke

    Methane Dehydrogenation and Coupling to Ethylene over a Mo/HZSM-5 Catalyst: A Density Functional Theory Study

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    In the present paper, we report the density functional theory studies on the structure of the molybdenum active center in Mo/HZSM-5 zeolite catalysts and the reaction mechanisms of methane dehydrogenation and coupling to ethylene (MDHC). Three kinds of active center models, Mo­(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub><sup>+</sup>, Mo<sub>2</sub>(CH<sub>2</sub>)<sub>4</sub><sup>2+</sup>, and Mo<sub>2</sub>(CH<sub>2</sub>)<sub>5</sub><sup>2+</sup>, were optimized for the carburized Mo species exchanged on the Brønsted acid sites in HZSM-5 zeolites. The entire catalytic cycle of MDHC was investigated, and the catalytic performances of three different active center models were compared. The catalytic cycle consists of four elementary steps: (1) dissociation of the methane C–H bond; (2) dehydrogenation and C–C coupling; (3) activation of the second methane molecule; (4) elimination of ethylene and molecular hydrogen. It was suggested that methane C–H bond dissociation occurs on the π-orbital of the MoCH<sub>2</sub> double bond, and C–C coupling proceeds on d-orbitals of the Mo atom. Dehydrogenation is realized by rupture of two C–H bonds from the adjacent methyl groups on the Mo atom, which is the rate-determining step of whole MDHC reactions

    Effectiveness and safety of azvudine in older adults with mild and moderate COVID-19: a retrospective observational study

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    Abstract Background Azvudine has clinical benefits and acceptable safety against COVID-19, including in patients with comorbidities, but there is a lack of available data for its use in older adult patients. This study explored the effectiveness and safety of azvudine in older adults with mild or moderate COVID-19. Methods This retrospective cohort study included patients aged ≥80 diagnosed with COVID-19 at the Central Hospital of Shaoyang between October and November 2022. According to the therapies they received, the eligible patients were divided into the azvudine, nirmatrelvir/ritonavir, and standard-of-care (SOC) groups. The outcomes were the proportion of patients progressing to severe COVID-19, time to nucleic acid negative conversion (NANC), and the 5-, 7-, 10-, and 14-day NANC rates from admission. Results The study included 55 patients treated with azvudine (n = 14), nirmatrelvir/ritonavir (n = 18), and SOC (n = 23). The median time from symptom onset to NANC of the azvudine, nirmatrelvir/ritonavir, and SOC groups was 14 (range, 6–25), 15 (range, 11–24), and 19 (range, 18–23) days, respectively. The median time from treatment initiation to NANC of the azvudine and nirmatrelvir/ritonavir groups was 8 (range, 4–20) and 9 (range, 5–16) days, respectively. The median length of hospital stay in the three groups was 10.5 (range, 5–23), 13.5 (range, 10–21), and 17 (range, 10–23) days, respectively. No treatment-related adverse events or serious adverse events were reported. Conclusion Azvudine showed satisfactory effectiveness and acceptable safety in older adults with mild or moderate COVID-19. Therefore, azvudine could be a treatment option for this special patient population
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