35 research outputs found

    Mechanism of ultrasonic cavitation to improve the effect of siderite on quartz flotation

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    In order to effectively eliminate the effect of fine carbonate minerals on quartz flotation, the influence of fine siderite on quartz flotation was studied as well as the mechanism or role of ultrasonic treatment in the process. The results of adsorption capacity measurement and flotation solution chemical calculation show that fine siderite and its dissolved components have a great influence on the collector consumption and the surface properties of quartz. In addition, SEM, EDS and XPS analysis were used to study the surface morphology and chemical environment changes of quartz with and without ultrasonic treatment. The results of flotation test show that the recovery of quartz increase from 38.79% to 58.38% under the condition that ultrasonic time was 0.5 min and ultrasonic power was200 W. The mechanical effect caused by ultrasonic cavitation can clean the quartz surface to a certain extent and increase its active sites, thus improving the floatability of quartz

    Comparative Study on Drying Characteristics and Quality of Apple Cubes Dried in Two Different Microwave Dryers

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    A rotary plate microwave dryer (RMD) and a newly-developed microwave convection coupled dryer (MCD) were used to dry apple cubes. The effects of microwave output power on drying, heating characteristics and quality attributes including scorching rate, color parameters, rehydration ratio, shrinkage, hardness, and sensory scores of the apple cubes were investigated and compared. The results showed that the microwave power required to complete drying in RMD was only 1/6 of that in MCD at the same microwave power density. Total drying time was 120, 60 and 30 min at 70, 210 and 350 W in RMD, respectively, while 160, 90, 80 and 60 min at 400; 800; 1,200; and 1,600 W in MCD, respectively. Compared with the products dried using hot air, the apple cubes dried in both dryers at the low microwave power had better rehydration capacity, less shrinkage and lower hardness as well as a* and b* value of color. Application of microwave power of over 800 W in MCD and over 210 W in RMD caused the increase in scorching rate as well as decreased the L* value and the sensory quality of the apple cubes. Microwave drying in MCD with temperature control improved the quality of the dried product. The microwave drying conditions suitable for the apple cubes were 400 W in MCD and 1,600 W in MCD with temperature control followed by 70 W in RMD; the products obtained under these three condition variants had superior or comparable quality to the products obtained upon conventional hot air-drying

    Effects of copper ions on malachite sulfidization flotation

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    In this study, the effects of copper ions (Cu2+) on the sulfidization (Na2S) flotation of malachite was investigated using micro-flotation experiments, zeta-potential measurements, X-ray photoelectron spectroscopy (XPS) analysis, adsorption experiments, and Materials Studio simulation. The results indicated that the flotation recovery of malachite decreased after the pretreatment of the mineral particles with Cu2+ ions prior to the addition of Na2S. The results for zeta-potential measurements and XPS analysis revealed that less sulfide ion species in the pulp solution transferred onto the mineral surface, the sulfidization of malachite surface weakened. The adsorption amount of collector on the mineral surface decreased, and this finding was confirmed by the results of the zeta-potential and adsorption experiments. Materials Studio simulation revealed that the adsorption energy of HS- ions and C4H9OCSS- ions on malachite surface increased after the adding of Cu2+ ion. The competitive adsorption made Cu2+ ions depress sulfidization flotation of malachite, the dissolution of mineral surface affected the adsorption of reagents on it, and decreased the floatability of malachite

    Aortic arch cannulation with the guidance of transesophageal echocardiography for Stanford type A aortic dissection

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    Abstract Background Aortic arch cannulation for an antegrade central perfusion during the surgery for Stanford type A aortic dissection can be performed within median sternotomy. We summarize the safety and convenient profile of the central cannulation strategy using the guidance of transesophageal echocardiography (TEE) in comparison to traditional femoral cannulation strategy. Methods Sixty-two patients with acute Stanford type A aortic dissection underwent aortic arch surgery in our hospital. All the patients were operated by the same surgeon. Cannulation was performed in 33 patients through the aortic arch under the guidance of TEE (Group A) and in 29 patients through the femoral artery (Group F). Under moderate hypothermic circulatory arrest, the brain is continuously perfused in an anterograde manner through the brachiocephalic and left common carotid arteries. Preoperative characeristics and surgical information were collected for each patient. Additionally, 30-day mortality rate and the incidence of the temporary neurological dysfunction were recorded as the outcomes. To compare the categorical variables, we used the chi-squared test. Continuous variables were compared using the t-test. Results Preoperative characteristics were almost similar between the two groups. The mean operation time (7.33 ± 1.14 h vs. 8.93 ± 2.59 h, P = 0.002) and the mean cardiopulmonary bypass (CPB) time (260.97 ± 45.14 min vs. 298.28 ± 95.89 min, P = 0.024) were significantly shorter in Group A than those in Group F. The 30-day mortality rates were 9.09 and 27.59% in Groups A and F, respectively (P = 0.057). And the incidences of temporary neurological dysfunction were 39.39 and 65.52% in Group A and F, respectively (P = 0.040). Conclusions Aortic arch cannulation with the guidance of TEE during the aortic arch surgery is a simple, fast, safe, and less invasive technique for establishing cardiopulmonary bypass for Stanford type A aortic dissection

    Enzymatically crosslinked gelatin hydrogel promotes the proliferation of adipose tissue-derived stromal cells

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    Gelatin hydrogel crosslinked by microbial transglutaminase (mTG) exhibits excellent performance in cell adhesion, proliferation, and differentiation. We examined the gelation time and gel strength of gelatin/mTG hydrogels in various proportions to investigate their physical properties and tested their degradation performances in vitro. Cell morphology and viability of adipose tissue-derived stromal cells (ADSCs) cultured on the 2D gel surface or in 3D hydrogel encapsulation were evaluated by immunofluorescence staining. Cell proliferation was tested via Alamar Blue assay. To investigate the hydrogel effect on cell differentiation, the cardiac-specific gene expression levelsof Nkx2.5, Myh6, Gja1, and Mef2c in encapsulated ADSCs with or without cardiac induction medium were detected by real-time RT-PCR. Cell release from the encapsulated status and cell migration in a 3D hydrogel model were assessed in vitro. Results show that the gelatin/mTG hydrogels are not cytotoxic and that their mechanical properties are adjustable. Hydrogel degradation is related to gel concentration and the resident cells. Cell growth morphology and proliferative capability in both 2D and 3D cultures were mainly affected by gel concentration. PCR result shows that hydrogel modulus together with induction medium affects the cardiac differentiation of ADSCs. The cell migration experiment and subcutaneous implantation show that the hydrogels are suitable for cell delivery

    Qualities of Life of Patients with Psychotic Disorders and Their Family Caregivers: Comparison between Hospitalised and Community-Based Treatment in Beijing, China

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    <div><p>Background</p><p>Community healthcare in mainland China is still at an early stage. The qualities of life (QOLs) of patients with psychotic disorders undergoing rehabilitation in hospitals or in the community, as well as those of their caregivers, may differ from each other.</p><p>Objectives</p><p>The study was performed to evaluate the QOL of patients with psychotic disorders and assess the differences in the QOLs between patients receiving care in diverse settings (hospital vs. the community).</p><p>Methods</p><p>This study was a descriptive study, in which all cases were collected from two psychiatric hospitals and five communities. Patients (n = 43) and caregivers (n = 40) in the psychiatric hospitals were grouped according to the length of illness and areas of residence and these criteria were also used to group patients (n = 55) and caregivers (n = 59) in the community. All participants were assessed using the WHOQOL-BREF (Chinese version). ANOVA was adopted to compare the QOL scores among the four groups (cases and caregivers in two settings), while confounding factors, such as age and marital status, were adjusted.</p><p>Results</p><p>Among the four groups of participants, namely, hospitalised and community patients and their corresponding caregivers, community samples had a significantly lower QOL score. The QOL score for the social relationships domain of the hospitalised patients’ caregivers was significantly higher than that of the caregivers of community patients (P = 0.019).</p><p>Conclusion</p><p>Community patients and their caregivers tend to have lower QOL scores than their hospitalised counterparts. The support of family members is urgently needed to provide better care for patients.</p></div

    Comparison of QOL scores among patients and caregivers of different residential settings in four domains.

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    <p>Comparison of QOL scores among patients and caregivers of different residential settings in four domains.</p
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