158 research outputs found

    Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

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    Ultrafine calcium carbonate is a widely used cheap additive. The research is conducted in low degree supersaturation solution in order to study the polymorphic phases’ change and its factors of the calcium carbonate precipitate in the ammonification-carbonization process of the solution with calcium. Fine particles of calcium carbonate are made in the solution containing 0.015 mol/L of Ca2+. Over 98% of the calcium carbonate precipitate without ammonification resembles the morphology of calcite, while the introduction of ammonia can benefit the formation of vaterite. It was inferred that the main cause should be serious partial oversaturation or steric effects. Ammonia also helps to form the twin spherical calcium carbonate. However, particles formed in the process of ammonification-carbonization in solution with low concentration degree of calcium are not even with a scale of the particle diameter from 5 to 12 μm. Inorganic salts, alcohol, or organic acid salts have significant controlling effect on the particle diameter of calcium carbonate and can help to decrease the particle diameter to about 3 μm. Anionic surfactants can prevent the conglobation of calcium carbonate particles and shrink its diameter to 500 nm–1 μm

    Asiatic acid exerts neuroprotective effect against hypoxicischemic brain injury in neonatal rats via inhibition of oxidative damage

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    Purpose: To investigate the effect of asiatic acid on hypoxic ischemia-induced injury in neonatal rats, and the underlying mechanism of action.Methods: Hypoxic-ischemia (HI) neonatal rat model was established via permanent ligation of the carotid artery, followed by hypoxia (exposure to 8 % oxygen and 92 % nitrogen) for 24 h. Immunofluorescence, using fluorescence microscope, was used for the determination of expressions of p-TAK1, NeuN and GFAP. Western blotting was used for assaying protein expression levels, while TUNEL assay was employed for the measurement of apoptosis.Results: Treatment of rats with asiatic acid prior to HI effectively prevented up-regulation of pTAK1 and decreased the count of p-TAK1-containing astrocytes. The proportion of NeuN containing p-TAK1 in HI rat brain cortex was significantly reduced by asiatic acid (p < 0.05). Treatment of rats with asiatic acid suppressed HI- induced up-regulation of pJNK expression. The HI-induced increase in the expression levels of caspase-3, p53 and p-c-Jun in rat brain cortex were reversed by asiatic acid (p < 0.05). The HImediated up-regulation of expressions of p- JNK, caspase-3, p53 and p-c-Jun in rat brain cortex were inhibited significantly by NG25. Asiatic acid treatment also significantly alleviated HI-mediated increase in apoptosis of neurons in rat brain cortex, when compared to model group (p < 0.05).Conclusion: These findings suggest that asiatic acid prevents HI-induced brain injury in neonatal rats via inhibition of neuronal apoptosis. Moreover, it inhibits TAK1 activation, suppresses p-JNK expression and targets pro-apoptotic factors in brain cortex. Therefore, asiatic acid may be a therapeutic agent for the management of HI-induced brain injury

    Study on Thermal Insulation Zeolite by Coal Fly Ash

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    This paper takes the coal fly ash as the material and makes zeolite with low thermal conductivity under a two-step synthesis for the purpose of thermal insulation. It studies main factors affecting zeolite such as the different concentration of NaOH, the solidliquid ratio, the silica-alumina ratio, and the crystallization temperature. The optimal conditions were obtained that the NaOH concentration was 3 mol/L, the solid-liquid ratio was 10 : 1, the silica-alumina ratio was 2, and the crystallization temperature was 12 ∘ C. Zeolites have multiple pores and skeletal structures under SEM observation. The mean particle size was 2.78 um of concentrated distribution. The pore volume was 0.148 m 3 /g measured by BET analysis, the specific surface was 118.6 m 2 /g, and the thermal conductivity was 0.153 W/(m⋅K). Zeolite was proved to be a qualified insulation material which can be used in thermal insulation coating as a new material of energy conservation

    Monitoring multi-temporal and spatial variations of water transparency in the Jiaozhou Bay using GOCI data

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    Water transparency, commonly measured as Secchi disk depth (SDD), is essential for describing the optical properties of coastal waters. We proposed a regional linear corrected SDD estimation model based on the North Sea Mathematical Models for GOCI and the mechanical model developed by Lee et al. (2015) in the Jiaozhou Bay. Combined with the multiple variable linear regression analysis, the diurnal SDD variations of the bay inside and the bay mouth are controlled by the solar zenith angle (SZA) and tides. The bay outside mainly varies with SZA. From GOCI observations between 2011 and 2021, wind force influenced the entire area on the inner-annual SDD variations. It exhibits an increasing trend in the inter-annual dynamics, which was more stable inside the bay with an annual increase of 0.035 m, and air temperature was the most significant contribution. However, human activities cannot be ignored in causing water environment changes

    Foreign body ingestion mimicking irritable bowel syndrome: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Foreign body ingestion is associated with a variety of symptoms and complications, often mimicking various diseases. This case report describes an unusual presentation following foreign body ingestion.</p> <p>Case presentation</p> <p>A 56-year-old Greek Caucasian woman presented to a primary care setting, in rural Crete, Greece, with complaints of abdominal pain, cramping and bloating, for the last four months. Alternating constipation and diarrhea was reported. The patient had unknowingly ingested a foreign body that resulted in an irritable bowel syndrome-like presentation.</p> <p>Conclusions</p> <p>This case report emphasizes the need for a high index of suspicion from physicians for a wide differential in their approach to abdominal complaints, as well as the importance of an individualized approach to patients in the setting of clinical medicine.</p

    Fecal Microbiota Transplant Decreases Mortality in Patients with Refractory Severe or Fulminant Clostridioides difficile Infection

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    Background & Aims Fecal microbiota transplantation (FMT) is recommended for recurrent Clostridioides difficile infection (CDI). FMT cures nearly 80% of patients with severe or fulminant CDI (SFCDI) when utilized in a sequential manner. We compared outcomes of hospitalized patients before and after implementation of an FMT program for SFCDI and investigated whether the changes could be directly attributed to the FMT program. Methods We performed a retrospective analysis of characteristics and outcomes of patients hospitalized for SFCDI (430 hospitalizations) at a single center, from January 2009 through December 2016. We performed subgroup analyses of 199 patients with fulminant CDI and 110 patients with refractory SFCDI (no improvement after 5 or more days of maximal anti-CDI antibiotic therapy). We compared CDI-related mortality within 30 days of hospitalization, CDI-related colectomy, length of hospital stay, and readmission to the hospital within 30 days before (2009–2012) vs after (2013–2016) implementation of the inpatient FMT program. Results CDI-related mortality and colectomy were lower after implementation of the FMT program. Overall, CDI-related mortality was 10.2% before the FMT program was implemented vs 4.4% after (P = .02). For patients with fulminant CDI, CDI-related mortality was 21.3% before the FMT program was implemented vs 9.1% after (P = .015). For patients with refractory SFCDI, CDI-related mortality was 43.2% before the FMT program vs 12.1% after (P < .001). The FMT program significantly reduced CDI-related colectomy in patients with SFCDI (6.8% before vs 2.7% after; P = .041), in patients with fulminant CDI (15.7% before vs 5.5% after; P = .017), and patients with refractory SFCDI (31.8% vs 7.6%; P = .001). The effect of FMT program implementation on CDI-related mortality remained significant for patients with refractory SFCDI after we accounted for the underlying secular trend (odds ratio, 0.09 for level change; P = .023). Conclusions An FMT program significantly decreased CDI-related mortality among patients hospitalized with refractory SFCDI
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