Enhanced Bauxite Recovery Using a Flotation Column Packed with Multilayers of Medium

An innovative self-designed medium was packed in a bench-scale flotation column to study its influence on the flotation recovery of bauxite. Computational fluid dynamics (CFD) simulation was conducted to reveal the impact of the packing medium on the turbulent characteristics of collection zone in the column. Simulation results show that multilayer packing of the medium divides the collection zone into small units having different turbulent intensities, which is more suitable for flotation separation. The packing medium decreases the turbulence kinetic energy (from 1.08 × 10−2 m2/s2 to 2.1 × 10−3 m2/s2), turbulence eddy dissipation (from 3.71 × 10−2 m2/s3 to 9.8 × 10−3 m2/s3) and axial fluid velocity of fluid in the column. With three layers of packing, the recovery of Al2O3 increased by 2.11% and the aluminum to silicon content ratio of the concentrate improved from 5.16 to 9.72

Effect of magnesium sulfate perioperative infusion on postoperative catheter-related bladder discomfort in male patients undergoing laparoscopic radical resection of gastrointestinal cancer: a prospective, randomized and controlled study

Abstract Background Laparoscopic radical resection of gastrointestinal cancer is associated with a high incidence of postoperative catheter-related bladder discomfort (CRBD). Studies on the benefits of magnesium sulfate intravenous infusion during the perioperative period post-laparoscopic surgery are yet lacking. Methods A total of 88 gastrointestinal cancer male patients scheduled for laparoscopic radical resection were randomly divided into two groups: normal saline (control) and magnesium. In the magnesium group, a 40 mg/kg loading dose of intravenous magnesium sulfate was administered for 10 min just after the induction of anesthesia, followed by continuous intravenous infusion of 15 mg/kg/h magnesium sulfate until the end of the surgery; the control group was administered the same dose of normal saline. Subsequently, 2 μg/kg sufentanil was continuously infused intravenously by a postoperative patient-controlled intravenous analgesia (PCIA) device. The primary outcome was the incidence of CRBD at 0 h after the surgery. The secondary outcomes included incidence of CRBD at 1, 2, and 6 h postsurgery, the severity of CRBD at 0, 1, 2, and 6 h postsurgery. Remifentanil requirement during surgery, sufentanil requirement within 24 h postsurgery, the postoperative numerical rating scale (NRS) score at 48 h after the surgery, magnesium-related side effects and rescue medication (morphine) requirement were also assessed. Results The incidence of CRBD at 0, 1, 2, and 6 h postoperatively was lower in the magnesium group than the control group (0 h: P = 0.01; 1 h: P = 0.003; 2 h: P = 0.001; 6 h: P = 0.006). The incidence of moderate to severe CRBD was higher in the control group at postoperative 0 and 1 h (0 h: P = 0.002; 1 h: P = 0.028), remifentanil requirement during surgery were significantly lower in the magnesium group than the control group. Sufentanil requirements during the 24 h postoperative period were significantly lower in the magnesium group than the control group. The NRS score was reduced in the magnesium group compared to the control group in the early postoperative period. Magnesium-related side effects and rescue medication (morphine) did not differ significantly between the two groups. Conclusions Intravenous magnesium sulfate administration reduces the incidence and severity of CRBD and remifentanil requirement in male patients undergoing radical resection of gastrointestinal cancer. Also, no significant side effects were observed. Trial registration Chictr.org.cn ChiCTR2100053073. The study was registered on 10/11/2021

Hemostatic Effects of Microbubble-Enhanced Low-Intensity Ultrasound in a Liver Avulsion Injury Model

<div><p>Objectives</p><p>Microbubble-enhanced therapeutic ultrasound (MEUS) can block the blood flow in the organs. The aim of this study was to evaluate the hemostatic effect of microbubble-enhanced pulsed, low-intensity ultrasound in a New Zealand White rabbit model of avulsion trauma of the liver. The therapeutic ultrasound (TUS) transducer was operated with the frequency of 1.2 MHz and an acoustic pressure of 3.4 MPa. Microbubble-(MB) enhanced ultrasound (MEUS) (n = 6) was delivered to the distal part of the liver where the avulsion was created. Livers were treated by TUS only (n = 4) or MB only (n = 4) which served as controls. Bleeding rates were measured and contrast enhanced ultrasound (CEUS) was performed to assess the hemostatic effect, and liver hemoperfusion before and after treatment. Generally, bleeding rates decreased more than 10-fold after the treatment with MEUS compared with those of the control group (P<0.05). CEUS showed significant declines in perfusion. The peak intensity value and the area under the curve also decreased after insonation compared with those of the control group (P<0.05). Histological examination showed cloudy and swollen hepatocytes, dilated hepatic sinusoids, perisinusoidal spaces with erythrocyte accumulation in small blood vessels, obvious hemorrhage around portal areas and scattered necrosis in liver tissues within the insonation area of MEUS Group. In addition, necrosis was found in liver tissue 48 h after insonation. We conclude that MEUS might provide an effective hemostatic therapy for serious organ trauma such as liver avulsion injury.</p></div

CEUS images after insonation.

<p><b>a, b</b>, Uniform perfusion of contrast agent in the MB group; <b>c, d</b>, A representative CEUS image showed a perfusion defect (arrow indicates the trauma, breakage the wound, and dotted line shows the range of defects. The area beyond the dotted line also showed an irregular defect) in MEUS group.</p

Images of procedure for application of microbubble-enhanced therapeutic ultrasound.

<p><b>a</b>’, active bleeding of the wound before insonation; <b>b</b>, Direct insonation of the wound by a transducer during injection of microbubbles; <b>c</b>, <b>c’,</b> small exudates over the wound after insonation; <b>d</b>, The liver wound were smooth and no bleeding after 48 h.</p

Correlation between bleeding rates and acoustic density analysis, bleeding visual score before and after insonation.

<p>PI means the peak intensity value, and AUC means the area under the curve.</p

Representative histological HE sections after insonation of the TUS, and, MB groups.

<p>Hepatic cord and plate structure were clear, and blood cells were scattered in the sinusoids (<b>a,b</b>); In the MEUS group, hepatocytes swelled, and erythrocytes accumulated in the sinusoids (<b>c</b>), the swollen hepatocytes deformed and compressed the sinusoids and perisinusoidal space. A large number of erythrocytes accumulated in the central veins (<b>d</b>), periportal connective tissue hemorrhaged (<b>e</b>). The targets showed map-like necrosis in the MEUS group after 48 h (<b>f</b>).</p

A comparison of bleeding visual scores before and after insonation.

<p>*P<0.05 indicates a significant difference between before and after insonation of MEUS group. ⁺P<0.05 indicates a significant difference between MEUS group and the controls.</p