Reduction of hematite (Fe2O3) to metallic iron (Fe) by CO in a micro fluidized bed reaction analyzer: A multistep kinetics study

A better understanding of the reduction kinetics of iron oxides in a fluidized bed promotes the development of relevant industrial processes, e.g. chemical looping combustion and non-blast furnace iron making. The reduction of iron oxides into iron is complex because the process is heterogeneous and several elementary reactions take place simultaneously. It is hard to figure out the reduction kinetics under fluidization in a fixed bed reactor such as in a thermogravimetry analyzer (TGA) which suffers from the limitations of heating rate, external diffusion, thermal pretreatment before reaction occurs. In this study, the reduction kinetics of hematite to metallic iron at different temperatures and carbon monoxide concentrations are experimentally investigated in a micro fluidized bed reaction analyzer (MFBRA), developed by the Institute of Process Engineering (IPE), Chinese Academy of Sciences (CAS) to develop the kinetics of fast gas-solid reactions. Results indicate that the reduction process has to be described by multistep kinetics and separated into several elementary reactions (i.e. hematite-magnetite, magnetite-wüsitite and wüsitite-iron), which proceed in parallel with different controlling mechanisms as well as with different time dependences. A multistep kinetics model based on Johnson-Mehl-Avrami (JMA) model is developed for the isothermal reduction process of hematite to metallic iron by taking into account the influences of reduction temperature and reducing gas concentration, using statistical analysis tools in the Statistical Product and Service Solutions (SPSS). The kinetics parameters, i.e. activation energy and pre-exponential factor, are determined for each elementary reaction. The contribution of each individual reaction to the whole reduction process is further discussed. The results also suggest that the reduction of hematite to wüsitite takes place fast and dominates the initial part of the entire reduction while the reduction of wüsitite to iron plays a less important role in the initial stage but controls the whole reduction in the late stage. The conclusions obtained in this study are comparable with that in the literature and indicate that the multistep kinetics model is able to capture the properties of both elementary reactions and the integrated process, providing an analysis strategy for revealing detail characteristics of the comple

Mechanisms of traditional Chinese medicine overcoming of radiotherapy resistance in breast cancer

Breast cancer stands as the most prevalent malignancy among women, with radiotherapy serving as a primary treatment modality. Despite radiotherapy, a subset of breast cancer patients experiences local recurrence, attributed to the intrinsic resistance of tumors to radiation. Therefore, there is a compelling need to explore novel approaches that can enhance cytotoxic effects through alternative mechanisms. Traditional Chinese Medicine (TCM) and its active constituents exhibit diverse pharmacological actions, including anti-tumor effects, offering extensive possibilities to identify effective components capable of overcoming radiotherapy resistance. This review delineates the mechanisms underlying radiotherapy resistance in breast cancer, along with potential candidate Chinese herbal medicines that may sensitize breast cancer cells to radiotherapy. The exploration of such herbal interventions holds promise for improving therapeutic outcomes in the context of breast cancer radiotherapy resistance

Therapeutic potential of microRNA-506 in cancer treatment: mechanisms and therapeutic implications

Cancer is a complex and highly lethal disease marked by unchecked cell proliferation, aggressive behavior, and a strong tendency to metastasize. Despite significant advancements in cancer diagnosis and treatment, challenges such as early detection difficulties, drug resistance, and adverse effects of radiotherapy or chemotherapy continue to threaten patient survival. MicroRNAs (miRNAs) have emerged as critical regulators in cancer biology, with miR-506 being extensively studied and recognized for its tumor-suppressive effects across multiple cancer types. This review examines the regulatory mechanisms of miR-506 in common cancers, focusing on its role in the competing endogenous RNA (ceRNA) network and its effects on cancer cell proliferation, apoptosis, and migration. We also discuss the potential of miR-506 as a therapeutic target and its role in overcoming drug resistance in cancer treatment. Overall, these insights underscore the therapeutic potential of miR-506 and its promise in developing novel cancer therapies

A widely distributed gene cluster compensates for uricase loss in hominids.

Approximately 15% of US adults have circulating levels of uric acid above its solubility limit, which is causally linked to the disease gout. In most mammals, uric acid elimination is facilitated by the enzyme uricase. However, human uricase is a pseudogene, having been inactivated early in hominid evolution. Though it has long been known that uric acid is eliminated in the gut, the role of the gut microbiota in hyperuricemia has not been studied. Here, we identify a widely distributed bacterial gene cluster that encodes a pathway for uric acid degradation. Stable isotope tracing demonstrates that gut bacteria metabolize uric acid to xanthine or short chain fatty acids. Ablation of the microbiota in uricase-deficient mice causes severe hyperuricemia, and anaerobe-targeted antibiotics increase the risk of gout in humans. These data reveal a role for the gut microbiota in uric acid excretion and highlight the potential for microbiome-targeted therapeutics in hyperuricemia

Efficacy and safety of tigecycline monotherapy vs. imipenem/cilastatin in Chinese patients with complicated intra-abdominal infections: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Tigecycline, a first-in-class broad-spectrum glycylcycline antibiotic, has broad-spectrum in vitro activity against bacteria commonly encountered in complicated intra-abdominal infections (cIAIs), including aerobic and facultative Gram-positive and Gram-negative bacteria and anaerobic bacteria. In the current trial, tigecycline was evaluated for safety and efficacy vs. imipenem/cilastatin in hospitalized Chinese patients with cIAIs.</p> <p>Methods</p> <p>In this phase 3, multicenter, open-label study, patients were randomly assigned to receive IV tigecycline or imipenem/cilastatin for ≤2 weeks. The primary efficacy endpoints were clinical response at the test-of-cure visit (12-37 days after therapy) for the microbiologic modified intent-to-treat and microbiologically evaluable populations. Because the study was not powered to demonstrate non-inferiority between tigecycline and imipenem/cilastatin, no formal statistical analysis was performed. Two-sided 95% confidence intervals (CIs) were calculated for the response rates in each treatment group and for differences between treatment groups for descriptive purposes.</p> <p>Results</p> <p>One hundred ninety-nine patients received ≥1 dose of study drug and comprised the modified intent-to-treat population. In the microbiologically evaluable population, 86.5% (45 of 52) of tigecycline- and 97.9% (47 of 48) of imipenem/cilastatin-treated patients were cured at the test-of-cure assessment (12-37 days after therapy); in the microbiologic modified intent-to-treat population, cure rates were 81.7% (49 of 60) and 90.9% (50 of 55), respectively. The overall incidence of treatment-emergent adverse events was 80.4% for tigecycline vs. 53.9% after imipenem/cilastatin therapy (<it>P </it>< 0.001), primarily due to gastrointestinal-related events, especially nausea (21.6% vs. 3.9%; <it>P </it>< 0.001) and vomiting (12.4% vs. 2.0%; <it>P </it>= 0.005).</p> <p>Conclusions</p> <p>Clinical cure rates for tigecycline were consistent with those found in global cIAI studies. The overall safety profile was also consistent with that observed in global studies of tigecycline for treatment of cIAI, as well as that observed in analyses of Chinese patients in those studies; no novel trends were observed.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00136201</p

Maintenance Chemotherapy With Chinese Herb Medicine Formulas vs. With Placebo in Patients With Advanced Non-small Cell Lung Cancer After First-Line Chemotherapy: A Multicenter, Randomized, Double-Blind Trial

Background: Chinese Herb Medicine Formulas (CHMF) was reported to improve the quality of life (QoL) in advanced NSCLC patients. The present study was designed to investigate whether maintenance chemotherapy plus CHMF in patients would improve QoL and progression-free survival (PFS).Methods: Seventy-one patients were enrolled from 8 medical centers in China, and were randomly assigned to a maintenance chemotherapy plus CHMF group (n = 35) or a maintenance chemotherapy plus placebo group (n = 36). The outcome measures included PFS, Karnofsky performance status (KPS) scores, QoL (assessed with the lung cancer symptom scale (LCSS) questionnaire), and adverse events (AEs).Results: Patients in the CHMF group showed significant improvements in median PFS (HR = 0.55, 95% CI 0.28–0.88, P = 0.019), KPS scores (P = 0.047), fatigue (cycle [C] 3: P = 0.03), interference with daily activities (C3: P = 0.04) and dyspnea (C2: P = 0.03) compared with patients in the placebo group. Compared with the placebo group, the incidence of AEs decreased in the CHMF group, including loss of appetite (C2: P = 0.011, C4: P = 0.004) and dry mouth (C4: P = 0.011).Conclusion: The essential finding of our study is that maintenance chemotherapy combined with CHMF may prolong PFS, relieve symptoms, improve QoL and alleviate the side effects

The impact of heat waves on children's health: a systematic review

Young children are thought to be particularly sensitive to heatwaves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children’s health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: “heatwave”, “heat wave”, “child health”, “morbidity”, “hospital admission”, “emergency department visit”, “family practice”, “primary health care”, “death” and “mortality”. Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children’s health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children’s health perspective, identifying the best measure of children’s exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children’s birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children’s disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended

Cognitive Processes of ESL Learners in Pragmatic Role-Play Tasks in Academic Settings

The purpose of the study was to investigate the cognitive processes of English as second language (L2) learners that are involved in their task-based pragmatic performances in academic settings. This study, therefore, examined the cognitive processes of 30 English L2 learners when engaging in various role-play-based pragmatic performances, such as requesting a recommendation letter from a professor and negotiating an agreeable meeting time with classmates. The qualitative analyses of the retrospective verbal reports (RVRs) data of the participants indicated that the learners employed a series of cognitive, metacognitive, and pragmatic strategies when accomplishing various speech acts (e.g., requests and refusals). This study hoped to make two new contributions to the field. First, the study provided empirical evidence to validate the theoretical taxonomy of the strategy use of learners in L2 pragmatics. Additionally, the theoretical foundations of current research on cognitive processes are primarily informed by pragmatic theories. Thus, the study aims to explicate a more comprehensive view of the cognitive processes of L2 learners in pragmatic performances by employing the theories from both pragmatic and learner strategy perspectives.</jats:p

A Multi-dimensional Examination of Strategic Competence in the Lexico-grammar Test Performance of Chinese EFL University Students

Despite the importance of strategic competence theory in language assessment, only a few studies have set out to validate it using empirical data. Phakiti (2007) points out that while human cognitive processing is subtle and highly dependent on context, little is known about the influence of strategic competence on test performance over time. This thesis reports on two empirical studies to address these issues. Study One is a large scale cross-sectional study (N=416) and Study Two a longitudinal one in which three lexico-grammatical tests and various sets of strategy use questionnaires were given to Chinese EFL students over 3 months (1-month interval; N=519). The cross-sectional study aimed to reveal the nature of strategic competence and provide a baseline model, while the longitudinal investigation aimed to assess and evaluate issues of ‘performance consistency’ (Chapelle, 1998), including both lexico-grammatical and strategic abilities, over time through a multi-trait multi-method (MTMM) approach (Campbell & Fiske, 1959), using structural equation modeling (SEM). Study One found that the nature of strategic competence is highly complex. Strategic competence was found to be a metacognitive function of human cognition associated with general strategic awareness and online strategic processing. Metacognitive awareness as a long-term mental process in L2 test-takers’ mind constantly manages and regulates their use of language in test-taking. Also, strategic competence does not directly contribute to language test performance since it acts as a cluster of strategic processing, which individually has a direct/indirect positive effect on test performance. The results of Study Two suggested that test-takers’ cognitive strategic processing used in tests became more stable and automatic, ie. test-takers might transition from being conscious to being unconscious of their mental processing. Additionally, strategic behaviours accounted for more when test-takers faced unfamiliar and difficult test tasks. However, even when the difficulty of the test tasks was similar, after test-takers’ strategic processing became automatic the impact of strategic thinking and behaviour accounted for less or little in their actual performances