Maximum Spreading of Impacting Ferrofluid Droplets under the Effect of Nonuniform Magnetic Field.

This article investigates the maximum spreading of ferrofluid droplets impacting on a hydrophobic surface under nonuniform magnetic fields. A generalized model for scaling the maximum spreading is developed. It is observed that, if the magnetic field strength is zero, a ferrofluid droplet not only demonstrates similar spreading dynamics as the water droplet but also obeys the same scaling law for the maximum spreading factor. Therefore, this article emphasizes the effects of magnetic field strength. In this regard, a dimensionless parameter (Nm) is introduced as the ratio between inertial force and Kelvin force, with an assumption that the kinetic energy mainly transforms to thermal energy. This parameter allows us to rescale all experimental data on a single curve with the Padé approximant, which is applicable to a wide range of impact velocities and magnetic field strengths.

Nocturnal dexmedetomidine alleviates post-intensive care syndrome following cardiac surgery: a prospective randomized controlled clinical trial.

BACKGROUND: Dexmedetomidine is a sedative agent that may have the potential to reduce the risk of post-intensive care syndrome (PICS). This study aimed to establish whether prophylactic nocturnal dexmedetomidine safely reduces postoperative PICS incidence and to develop an easy-to-use model for predicting the risk of PICS following cardiac surgery. METHODS: This was a single-center, double-blind, randomized, prospective, placebo-controlled trial. Patients undergoing cardiac surgery were randomly assigned (1:1) to dexmedetomidine or placebo (normal saline) groups between January 2019 and July 2020. Dexmedetomidine or a similar volume of saline was administered, with an infusion rate up to 1.2 µg/kg/h until the RASS remained between - 1 and 0. The primary study endpoint was PICS incidence at 6 months follow-up, as defined by cognitive, physical, or psychological impairments. RESULTS: We assessed 703 individuals for eligibility, of whom 508 were enrolled. Of these, there were 251 in the dexmedetomidine group and 257 in the placebo group that received the trial agent, forming a modified intention-to-treat population. PICS incidence at 6-month follow-up was significantly decreased in the dexmedetomidine group (54/251, 21.5%) relative to the placebo group (80/257, 31.1%) (odds ratio [OR] 0.793, 95% CI 0.665-0.945; p = 0.014). Psychological impairment was significantly reduced in the dexmedetomidine group relative to the placebo group (18.7% vs. 26.8%, OR 0.806, CI 0.672-0.967, p = 0.029). However, dexmedetomidine treatment was associated with a higher rate of hypotension. A nomogram revealed that age, education, a medical history of diabetes and smoking, dexmedetomidine treatment, postoperative atrial fibrillation, and sequential organ failure assessment scores at 8 h post-surgery were independent predictors of PICS. CONCLUSIONS: Prophylactic nocturnal dexmedetomidine administration significantly reduced PICS incidence by a marked reduction in psychological impairment within a 6-month follow-up period. TRIAL REGISTRATION: ChiCTR, ChiCTR1800014314 . Registered 5 January 2018, http://www.chictr.org.cn/index.aspx.

Effect of self-assembly on fluorescence in magnetic multiphase flows and its application on the novel detection for COVID-19.

In the present study, the magnetic field induced self-assembly processes of magnetic microparticles in an aqueous liquid (the pure magnetic fluid) and nonmagnetic microparticles in ferrofluid (the inverse magnetic fluid) are experimentally investigated. The microparticles are formed into chain-like microstructures in both the pure magnetic fluid and the inverse magnetic fluid by applying the external magnetic field. The fluorescence parameters of these self-assembled chain-like microstructures are measured and compared to those without the effect of magnetic field. It is found that the fluorescence in the pure magnetic fluid is weakened, because the scattering and illuminating areas are reduced in the microstructures. On the contrary, the fluorescence in the inverse magnetic fluid is enhanced, because more fluorescent nonmagnetic microparticles are enriched and become detectable under the effect of the magnetic dipole force and the magnetic levitational force, and their unnecessary scattering can be absorbed by the surrounding ferrofluid. The average enhancement of the fluorescence area ratio in the inverse magnetic fluid with 3 µm nonmagnetic microparticles reaches 112.92%. The present work shows that the inverse magnetic fluid has advantages such as low cost, no scattering effect, stable fluorescence intensity, and relatively low magnetic resistance. In the end, a prototype design for the novel detection of coronavirus disease 2019 based on the magnetic field induced self-assembly in the inverse magnetic fluid is proposed, which could support the epidemic prevention and control.

MiR-146b protects cardiomyocytes injury in myocardial ischemia/reperfusion by targeting Smad4.

MicroRNAs, a class of small and non-encoding RNAs that transcriptionally or post-transcriptionally modulate the expression of their target genes, have been implicated as critical regulatory molecules in many cardiovascular diseases, including ischemia-/reperfusion-induced cardiac injury. In the present study, we report on the role of miR-146b in myocardial I/R injury and the underlying cardio-protective mechanism. Antagomir-146b was used to explore the effects of miR-146b on cardiac ischemia/reperfusion injury (30 min ischemia followed by 180 min reperfusion). As predicted, miR-146b overexpression significantly reduced the infarct size and cardiomyocytes apoptosis and release of creatine kinase and lactate dehydrogenase. In addition, miR-146b attenuated H9c2 cell apoptosis. Furthermore, Smad4 was predicted and verified as a potential miR-146b target using bioinformatics and luciferase assay. In summary, this study demonstrated that miR-146b plays a critical protective role in cardiac ischemic injury and may provide a new therapeutic approach for the treatment of myocardial I/R injury.

Surgical repair of sinus of Valsalva aneurysm in Asian patients.

BACKGROUND: Sinus of Valsalva aneurysm is a rare cardiac anomaly, and the difference between Asian and Western countries in its occurrence is not well established. This study was designed to investigate the difference between Asian and Western patients. METHODS: Between September 1988 and February 2006, 83 patients with sinus of Valsalva aneurysm underwent surgical repair in our institute. The aneurysms originated from the right and noncoronary sinus in 74 and 9, respectively, and ruptured into the right ventricle in 52 patients, the right atrium in 30, and the left ventricle in 1. Ventricular septal defect (n = 38), aortic regurgitation (n = 21), and bicuspid aortic valve (n = 4) were the common coexisting anomalies. To compare the differences between Asian and Western patients in sinus of Valsalva aneurysm, 1049 cases (654 Asian patients versus 395 Western) were collected from the literature. RESULTS: Sixty-six patients were followed up for 9.6 +/- 3.8 years. The cardiac function of 15 patients with aortic regurgitation was worse than that of those with no aortic regurgitation (p < 0.05). There was no difference between the direct closure and the patch closure (p > 0.05). Analysis of all collected cases revealed that aneurysm of the sinus of Valsalva in Asian patients compared with Western series is characterized by a higher incidence, more aneurysms originating from the right coronary sinus (85.8% versus 67.9%), more aneurysm rupture into the right ventricle (72.5% versus 60%), a higher incidence of association with ventricular septal defect (52.4% versus 37.5%), and lower incidence of association with bicuspid aortic valve (0.6% versus 7.8%). However, both Asian and Western patient series have similar incidence of combination with aortic regurgitation (33.6% versus 32.7%). CONCLUSIONS: Long-term results of ruptured sinus of Valsalva aneurysm are associated with preoperative aortic regurgitation. The difference between Asian and Western patients with ruptured aneurysm of the sinus of Valsalva is significant.

[Clinical analysis for 70 sinus of valsalva aneurysm].

OBJECTIVE: To review retrospectively the experience of surgical repair of sinus of valsalva aneurysm (SVA) in 70 patients. METHODS: Between September, 1988 and October, 2003, Seventy patients with SVA underwent surgical repair by the aid of general anesthesia and cardiopulmonary bypass, comprised 1.4% (70/4960) of all open-heart operation. Forty-five were male and 25 female. Age ranged from 3 to 69 years old [mean (29 +/- 15) years]. The aneurysms ruptured into the right ventricle in 46 patients, right atrium in 23 and left ventricle in 1 respectively. The aneurysms originated from right and noncoronary sinus in 61 patients (87%) and 9 patients (13%) respectively. The most common associated cardiovascular lesions were ventricular septal defect (VSD, n = 34) and aortic valve incompetence (n = 21). Repairs were achieved through an incision in right atriotomy, right ventriculotomy or aortotomy only or both aortotomy and right atriotomy (or right ventriculotomy). The defects in the sinus of valsalva was repaired with either direct sutures (n = 43) or a patch (n = 27). The aortic valve was replaced in 6 patients. RESULTS: There were no deaths in early time after repair. Postoperative hospital stay was 8 approximately 33 days [mean +/- standard deviation, (14.3 +/- 6.4) days] before 1997 and 6 approximately 15 days [mean +/- standard deviation, (9.1 +/- 2.6) days] after 1997 respectively. Complications included infection (n = 4), hemorrhage (n = 4), pneumothorax (n = 1), arrhythmia (n = 4) and residual shunt (n = 1) of VSD. Fifty-three (76%) patients (2 months approximately 13 years) were followed-up [mean +/- standard deviation, (6.6 +/- 3.8) years]. All patients survived except that one died of rupture of dissecting aortic aneurysm 7 years after operation. CONCLUSIONS: The ruptured sinus of valsalva aneurysm and unruptured sinus of valsalva aneurysm with ventricle septal defect or(and) aortic valve regurgitation should be repaired surgically as soon as the diagnosis was confirmed. Long-term results are associated with preoperative aortic valve regurgitation.