Mirizzi syndrome: Problems and strategies.

Mirizzi syndrome is a serious complication of gallstone disease. It is caused by the impacted stones in the gallbladder neck or cystic duct. One of the features of Mirizzi syndrome is severe inflammation or dense fibrosis at the Calot's triangle. In our clinical practice, bile duct, branches of right hepatic artery and right portal vein clinging to gallbladder infundibulum are often observed due to gallbladder infundibulum adhered to right hepatic hilum. The intraoperative damage of branches of right hepatic artery occurs more easily than that of bile duct, all of which are hidden pitfalls for surgeons. Magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) are the preferable tools for the diagnosis of Mirizzi syndrome. Anterograde cholecystectomy in Mirizzi syndrome is easy to damage branches of right hepatic artery and bile duct due to gallbladder infundibulum adhered to right hepatic hilum. Subtotal cholecystectomy is an easy, safe and definitive approach to Mirizzi syndrome. When combined with the application of ERCP, a laparoscopic management of Mirizzi syndrome by well-trained surgeons is feasible and safe. The objective of this review was to highlight its existing problems: (1) low preoperative diagnostic rate, (2) easy to damage bile duct and branches of right hepatic artery, and (3) high concomitant gallbladder carcinoma. Meanwhile, the review aimed to discuss the possible therapeutic strategies: (1) to enhance its preoperative recognition by imaging findings, and (2) to avoid potential pitfalls during surgery.

Telomere G-triplex lights up Thioflavin T for RNA detection: new wine in an old bottle.

Few reports are found working on the features and functions of the human telomere G-triplex (ht-G3) though the telomere G-quadruplex has been intensely studied and widely implemented to develop various biosensors. We herein report that ht-G3 lights up Thioflavin T (ThT) and establish a sensitive biosensing platform for RNA detection by introducing a target recycling strategy. An optimal condition was selected out for ht-G3 to promote ThT to generate a strong fluorescence. Accordingly, an ht-G3-based molecular beacon was successfully designed against the corresponding RNA sequence of the SARS-CoV-2 N-gene. The sensitivity for the non-amplified RNA target achieves 0.01 nM, improved 100 times over the conventional ThT-based method. We believe this ht-G3/ThT-based label-free strategy could be widely applied for RNA detection.

Post-operative uric acid: a predictor for 30-days mortality of acute type A aortic dissection repair.

BACKGROUND: Hyperuricemia is associated with aortic dissection and cardiovascular diseases. The implication of high serum uric acid (UA) level after acute aortic dissection repair remains unknown. The aim of this study is to explore the role of peri-operative serum UA level in predicting 30-days mortality with acute type A aortic dissection (AAAD) patients, who underwent surgery. METHODS: This study retrospectively enrolled 209 consecutive patients with AAAD, who underwent surgery in Xiangya Hospital from 2017 to 2020. Post-operative laboratory examinations were measured within 24 h after surgery. Univariate analysis and logistic regression analysis were used for predictor finding. RESULTS: 209 consecutive AAAD patients were included, 14.3% (n = 30) were dead within 30 days after surgery. By univariate analysis, we found AAAD repair patients with 30-days mortality had a higher prevalence of cerebral malperfusion, lower pre-operative fibrinogen, longer cardiopulmonary bypass and aortic crossclamp time, and higher post-operative day 1 (POD1) creatinine and urea levels. Both pre-operative (433.80 ± 152.59 vs. 373.46 ± 108.31 mmol/L, p = 0.038) and POD1 (559.78 ± 162.23 vs. 391.29 ± 145.19 mmol/L, p < 0.001) UA level were higher in mortality group than in survival group. In regression model, only cerebral malperfusion (OR, 7.938, 95% CI 1.252-50.323; p = 0.028) and POD1 UA level (OR, 2.562; 95% CI 1.635-4.014; p < 0.001) were independent predictors of 30-days mortality in AAAD repair patients. According to the ROC curve, the POD1 UA level provided positive value for 30-days mortality in AAAD repair patients with 0.799 areas under the curve. The optimum cutoff value selected by ROC curve was 500.15 mmol/L, with a sensitivity of 65% and a specificity of 86%. CONCLUSION: Pre- and post-operative hyperuricemia are potentially associated with worsened outcomes in AAAD surgery patients. The POD1 UA level has a predictive role in 30-days mortality in AAAD repair patients.

Application of retrograde cerebral perfusion in aortic root replacement combined with right half aortic arch replacement. / é€†è¡Œè„‘çŒæ³¨åœ¨ä¸»åŠ¨è„‰æ ¹éƒ¨å’Œå³åŠå¼“ç½®æ¢æ‰‹æœ¯ä¸­çš„åº”ç”¨.

OBJECTIVES: After cardiac surgery involving the aortic arch, the incidence of neurological complications remains high, therefore it is very important to take measures to protect brain. This study is to investigate the safety and effectiveness of deep hypothermic circulatory arrest and retrograde cerebral perfusion for aortic root combined with right half aortic arch replacement. METHODS: Clinical data of 31 patients, who underwent aortic root and right half aortic arch replacement with deep hypothermic circulatory arrest and retrograde cerebral perfusion in Xiangya Hospital, Central South University, were retrospectively analyzed. This cohort included 23 aortic aneurysms and 8 aortic dissections. Aortic root replacement was conducted in 26 patients by Bentall procedures, and 5 patients by David procedures. Time of deep hypothermic circulatory arrest and retrograde cerebral perfusion in surgery was (21.9±5.2) min. The in-hospital mortality, postoperative neurological dysfunction and other major adverse complications were observed and recorded. RESULTS: No in-hospital death and permanent neurological dysfunction occurred. Two patients had transient neurological dysfunction and 2 patients with aortic dissection requiring long-time ventilation due to hypoxemia, 1 patient underwent resternotomy. During 6-36 months of follow-up, all patients recovered satisfactorily. CONCLUSIONS: Deep hypothermic circulatory arrest and retrograde cerebral perfusion can be safely and effectively applied in aortic root and right half aortic arch replacement, and which can simplify the surgical procedures and be worth of clinical promotion.

Admission white blood cell count predicts post-discharge mortality in patients with acute aortic dissection: data from the MIMIC-III database.

BACKGROUND: Inflammation underlies both the pathogenesis and prognosis in patients with acute aortic dissection (AAD). This study aimed to assess the association of ICU admission of white blood cell count (WBCc) with post-discharge mortality in these patients. METHODS: Clinical data were extracted from the MIMIC-III V1.4 database. After adjusted to covariables, Cox regression analysis and Kaplan-Meier survival curve were performed to determine the relationship between WBCc on admission and post-discharge mortality (30-day, 90-day, 1-year and 5-year) in AAD patients. Subgroup analysis and receiver operating characteristic (ROC) curve analysis were used to test the performance of WBCc in predicting mortality in AAD patients. RESULTS: A total of 325 eligible patients were divided into 2 groups: normal-WBCc group (≤ 11 k/uL) and high-WBCc group (> 11 K/uL). In univariate Cox regression analysis, high WBCc was significant risk predictor of 30-day, 90-day, 1-year and 5-year mortality [hazard ratio (HR), 95% CI, P 2.58 1.36-4.91 0.004; 3.16 1.76-5.70 0.000; 2.74 1.57-4.79 0.000; 2.10 1.23-3.54 0.006]. After adjusting for age and other risks, high WBCc remained a significant predictor of 30-day, 90-day and 1-year mortality in AAD patients (HR, 95% CI, P 1.994 1.058-3.76 0.033; 2.118 1.175-3.819 0.013; 2.37 1.343-4.181 0.003). The area under ROC curve of WBCc for predicting 30-day, 90-day, 1-year and 5-year mortality were 0.69, 0.70, 0.66 and 0.61, respectively. The results from subgroups analysis showed that there was no interaction in most strata and patients who were younger than 69 years of age or had history of respiratory disease with an elevated WBCc had an excess risk of 30-day mortality (HR, 95% CI, P 3.18 1.41-7.14 0.005; 3.84 1.05-14.13 0.043). CONCLUSIONS: Higher than normal WBCc on admission may predict post-discharge mortality in patients with AAD.

Treatment of thoracoabdominal aortic aneurysm by prosthetic vessel replacement under left heart bypass. / å·¦å¿ƒè½¬æµä¸‹äººå·¥è¡€ç®¡ç½®æ¢æœ¯æ²»ç–—èƒ¸è ¹ä¸»åŠ¨è„‰ç˜¤.

OBJECTIVES: Thoracoabdominal aortic aneurysm (TAAA) prosthetic vessel replacement is one of the most complex operations in the field of cardiovascular surgery. The key to success of this operation is to prevent and avoid ischemia of important organs while repairing TAAA. This study aims to summarize and analyze the effect of prosthetic vessel replacement under left heart bypass in the treatment of TAAA. METHODS: Data of 15 patients with TAAA who underwent prosthetic vessel replacement under left heart bypass in Xiangya Hospital of Central South University were retrospectively analyzed. According to Crawford classification, there were 2 cases of type I, 8 cases of type II, 3 cases of type III, and 2 cases of type V. There were 14 cases of selective operation and 1 case of emergency operation. All operations were performed under left heart bypass, and cerebrospinal fluid drainage was performed before operation. Left heart bypass was established by intubation of left inferior pulmonary vein and distal abdominal aorta or left femoral artery. The thoracoabdominal aorta was replaced segment by segment. After aortic dissection, the kidneys were perfused with cold crystalloid renal protective solution, and the celiac trunk and superior mesenteric artery were perfused with warm blood. RESULTS: One patient with TAAA after aortic dissection of type A died. During the operation, straight blood vessels were used to repair TAAA, and the celiac artery branches were trimmed into island shape and anastomosed with prosthetic vessels. After the operation, massive bleeding occurred at the anastomotic stoma, then anaphylactic reaction occurred during massive blood transfusion, resulting in death. One patient suffered from paraplegia due to ischemic injury of spinal cord. The other patients recovered well and were discharged. The postoperative ventilation time was (16.5±13.8) h and the postoperative hospital stay was (10±4) d. The amount of red blood cell transfusion was (13±9) U. The patients were followed up for 2 months to 2 years, and the recovery was satisfactory. CONCLUSIONS: The effect of prosthetic vessel replacement under left heart bypass in the treatment of TAAA is good, which is worthy of clinical promotion.

The omitted symptoms challenge the diagnosis of right atrial myxoma: a case report.

BACKGROUND: Cardiac myxoma (CM) is the most common type of primary cardiac tumors. The prevalence of primary cardiac tumors is 0.0017-0.28% in various autopsy studies. The clinical symptoms of CM which includes embolism, intracardiac obstruction, general or constitutional manifestations and infected myxoma are largely depended on the size, growing speed, location and pedicle length of the tumor. The following case reported a missed diagnostic case of a right atrial myxoma firstly presented digestive, systemic symptoms and immunologic disorder, leading to emergent tricuspid valves obstruction situation. CASE PRESENTATION: We reported a critical case of a 51-year-old female with CM was firstly admitted to the gastroenterology clinical department because of poor appetite, marked fatigability and weight loss for 2 months. The physician diagnosed her as chronic gastritis and treated her with some symptomatic treatment such as ilaprazole and magnesium aluminum carbonate. After months without definitive diagnosis, this right atrial myxoma grew into right ventricle and obstructed the tricuspid valves, causing her dyspnea, sweating, dizziness, feeling of impending death when she was sleeping. Transthoracic echocardiogram revealed a 6.1 × 4.2 × 3.7 cm2 mass adjacent to tricuspid valves. The patient underwent surgical excision and pathology revealed a primary cardiac myxoma. CONCLUSION: This case reported a critical result of missed diagnosis of right atrial myxoma and showed its systematic symptoms and immunologic disorder, highlighting the importance of systematic examinations on patients. Furthermore, it appeals early diagnosis of CM and consideration of drug targets to suppress CM development.

Curcumin attenuates endothelial cell fibrosis through inhibiting endothelial-interstitial transformation.

Curcumin (Cur) has various pharmacological activities, including anti-inflammatory, antiapoptotic and anticancer effects. However, there is no report on the effect of Cur on endothelial cell fibrosis. This study was designed to investigate the effect and mechanism of Cur on endothelial cell fibrosis. An endothelial cell fibrosis model was established by using transforming growth factor (TGF) induction. Proliferation assays, qRT-PCR, western blotting and immunostaining were performed to investigate the effects and mechanism of Cur on endothelial cell fibrosis. We found that in human umbilical vein endothelial cells (HUVECs), TGF-ß1 treatment significantly decreased the expression of nuclear factor erythroid-2-related factor 2 (NRF-2), dimethylarginine dimethylaminohydrolase-1 (DDAH1), and VE-cadherin, the secretion of cellular nitric oxide (NO) and the activity of nitrous oxide synthase (NOS), while asymmetric dimethylarginine (ADMA) and the release of inflammatory factors were elevated. Immunofluorescence showed decreased CD31 and increased α-smooth muscle actin (α-SMA). Overexpression of NRF-2 significantly attenuated the effects of TGF-ß1, while downregulation of DDAH1 potently counteracted the effect of NRF-2. In addition, ADMA treatment resulted in similar results to those of TGF-ß1, and Cur significantly attenuated the effect of TGF-ß1, accompanied by increased VE-cadherin, DDAH1 and NRF-2 and decreased matrix metalloproteinase-9 (MMP-9) and extracellular regulated protein kinases 1/2 (ERK1/2) phosphorylation. The NRF-2 inhibitor ML385 had the opposite effect as that of Cur. These results demonstrated that Cur inhibits TGF-ß1-induced endothelial-to-mesenchymal transition (EndMT) by stimulating DDAH1 expression via the NRF-2 pathway, thus attenuating endothelial cell fibrosis.

Risk factors of early mortality after surgical treatment for infective endocarditis. / æ„ŸæŸ“æ€§å¿ƒå† è†œç‚Žæ‚£è€ æœ¯åŽæ—©æœŸæ­»äº¡çš„å±é™©å› ç´ .

OBJECTIVES: To explore the basic clinical characteristics and relevant factors affecting the early postoperative prognosis in patients with infective endocarditis (IE). METHODS: A total of 702 patients with IE, who underwent surgery in Xiangya Hospital, Central South University from January 1981 to June 2019, were studied and the data were collected through the paper records and the hospital information system. The patients from January 1981 to June 2010 served as an early group (n=224), and other patients from July 2010 to June 2019 served as a recent group (n=478). Independent risk factors for early postoperative death were determined by logistic regression analysis. RESULTS: The mean age of the 702 patients was 36.7±16.1 years, and the male accounted for 68.1%. Preoperative stroke occurred in 71 patients (10.1%), and dialysis was done in 14 patients (2%) preoperatively. Streptococcus were the pathogenic bacteria in 172 patients, accounting for 59.5% of all positive blood culture results. In the early group, the percentage of IE combined with congenital heart disease was significantly higher than that in the recent group [77 patients (34.4%) in the early group vs 22 patients (4.6%) in the recent group; P<0.05]. Postoperative stroke occurred in 15 patients (2.1%), while 59 patients (7%) required new dialysis postoperatively because of renal insufficiency. Twenty-nine patient died in the post-operation, with 4.1% in 30-day mortality. Logistic regression analysis revealed that the high preoperative New York Heart Association (NYHA) grade of cardiac function (OR=3.22, 95% CI 1.50-6.88; P<0.01), postoperative stroke (OR=5.75, 95% CI 1.22-27.07; P<0.05), postoperative dialysis (OR=15.53, 95% CI 3.50-68.82; P<0.01), perivalvular abscess (OR=13.19, 95% CI 3.83-45.42; P<0.01) and multivalve involvement (OR=3.57, 95% CI 1.24-10.30; P<0.05) were the independent risk factors for early mortality. CONCLUSIONS: Streptococcus is the most common pathogenic bacteria in the patients with IE. Surgery for IE can obtain a satisfactory early outcomes. High preoperative NYHA grade of cardiac function, postoperative stroke, postoperative dialysis, perivalvular abscess and multivalve involvement are the independent risk factors for early mortality.

Heparin-Induced Thrombocytopenia in Infants after Heart Surgery.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) in infants is a rare disorder, and the diagnosis and management of HIT still remains challenging. Argatroban is a synthetic direct thrombin inhibitor (DTI) that is widely used for treating HIT. However, little is known about the efficacy of the activated clotting time (ACT) test in monitoring DTI treatment as an alternative to the routinely used activated partial thromboplastin time (aPTT). METHODS: Between July 2013 and January 2015, four infants were diagnosed with HIT after surgical correction of congenital anomalies. In all cases, heparin was used during cardiopulmonary bypass (CPB). Diagnosis of HIT was based on the "4 Ts" pretest clinical scoring system, and platelet factor 4 (PF4) antibody was detected using enzyme-linked immunosorbent assay. Argatroban was used in treating HIT. When argatroban was infused, anticoagulation tests (aPTT, prothrombin time [PT], thrombin time [TT], and fibrinogen) were performed every 4 to 12 hours. ACT was used in addition to monitor the anticoagulation effect of argatroban. The target ACT was 1.5 to 3.0 times the baseline. ACT was measured every 2 to 4 hours and remeasured 1 hour after each dosage adjustment. RESULTS: Thrombocytopenia (defined as a 50% decrease in platelet count) occurred during the 3rd to 6th day postoperatively. After the diagnosis of HIT, argatroban was started immediately, and platelet counts stabilized and gradually increased. Anticoagulation effect of argatroban was successful monitored by ACT and aPTT. Poor correlation between the ACT test and aPTT test (R = 0.270, p = 0.092) was noted in one patient. ACT values increased rapidly after 3 to 7 days on argatroban treatment. In most cases, low dosage of argatroban was given ranging from 0.04 to 5.00 µg/kg/min. CONCLUSION: Argatroban may be an effective medicine in treating HIT in infants, in a reduced dosage. The great fluctuation in argatroban dosage during the course of HIT treatment necessitates close monitoring. ACT test may be reliable and convenient for monitoring HIT treatment and may contribute to positive clinical outcomes in infants. The efficacy of argatroban and the use of ACT monitoring in the management of HIT infants needs further study.

Pressure-induced superconductivity in a three-dimensional topological material ZrTe5.

As a new type of topological materials, ZrTe5 shows many exotic properties under extreme conditions. Using resistance and ac magnetic susceptibility measurements under high pressure, while the resistance anomaly near 128 K is completely suppressed at 6.2 GPa, a fully superconducting transition emerges. The superconducting transition temperature Tc increases with applied pressure, and reaches a maximum of 4.0 K at 14.6 GPa, followed by a slight drop but remaining almost constant value up to 68.5 GPa. At pressures above 21.2 GPa, a second superconducting phase with the maximum Tc of about 6.0 K appears and coexists with the original one to the maximum pressure studied in this work. In situ high-pressure synchrotron X-ray diffraction and Raman spectroscopy combined with theoretical calculations indicate the observed two-stage superconducting behavior is correlated to the structural phase transition from ambient Cmcm phase to high-pressure C2/m phase around 6 GPa, and to a mixture of two high-pressure phases of C2/m and P-1 above 20 GPa. The combination of structure, transport measurement, and theoretical calculations enable a complete understanding of the emerging exotic properties in 3D topological materials under extreme environments.

Superconductivity in Pristine 2H_{a}-MoS_{2} at Ultrahigh Pressure.

As a follow-up of our previous work on pressure-induced metallization of the 2H_{c}-MoS_{2} [Chi et al., Phys. Rev. Lett. 113, 036802 (2014)PRLTAO0031-900710.1103/PhysRevLett.113.036802], here we extend pressure beyond the megabar range to seek after superconductivity via electrical transport measurements. We found that superconductivity emerges in the 2H_{a}-MoS_{2} with an onset critical temperature T_{c} of ca. 3 K at ca. 90 GPa. Upon further increasing the pressure, T_{c} is rapidly enhanced beyond 10 K and stabilized at ca. 12 K over a wide pressure range up to 220 GPa. Synchrotron x-ray diffraction measurements evidenced no further structural phase transition, decomposition, and amorphization up to 155 GPa, implying an intrinsic superconductivity in the 2H_{a}-MoS_{2}. DFT calculations suggest that the emergence of pressure-induced superconductivity is intimately linked to the emergence of a new flat Fermi pocket in the electronic structure. Our finding represents an alternative strategy for achieving superconductivity in 2H-MoS_{2} in addition to chemical intercalation and electrostatic gating.

Galectin-3 activates TLR4/NF-κB signaling to promote lung adenocarcinoma cell proliferation through activating lncRNA-NEAT1 expression.

BACKGROUND: Lung cancer remains the top contributor to cancer-related mortality worldwide. Long non-coding RNAs (lncRNAs) have been reported to participate in normal development and tumorigenesis. LncRNA nuclear enriched abundant transcript 1 (NEAT1) is highly expressed in lung cancer and promotes lung cancer cell proliferation and migration. However, the upstream regulatory mechanism still needs investigation. METHODS: In the present study, we investigated the upstream regulators and mechanisms of NEAT1 expression disorders. We first examined NEAT1 expression in lung adenocarcinoma tissues and its correlation with clinic features in patient with lung adenocarcinoma; next, the detailed function of NEAT1 in lung cancer cell proliferation and migration was assessed. To investigate whether NF-κB acts as a transcription factor of NEAT1 to activate its expression, we validated the combination between NF-κB and NEAT1, and NF-κB regulation of NEAT1 upon LPS stimulation. Further, the effect of NF-κB upstream regulator, TLR4, on NEAT1 expression upon LPS stimulation was examined. Galectin-3 reportedly serves as a ligand of TLR4 and promotes TLR4, MyD88 and p-p65 expression; we investigated whether Galectin-3 could modulate lung adenocarcinoma cell proliferation and migration through TLR4/NF-κB/NEAT1. Finally, the expression and correlation of the above factors in lung adenocarcinoma tissues was validated. RESULTS: NEAT1 is highly expressed in lung adenocarcinoma tissues and promotes lung cancer cell proliferation and migration. NF-κB binds to NEAT1 promoter to activate NEAT1 expression after LPS-stimulated p65 nucleus translocation. LPS stimulation activates TLR4 signaling, followed by downstream NF-κB activation, and ultimately NEAT1 expression activation. Galectin-3 activates TLR4 signaling thus affecting lung cancer cell proliferation and migration through TLR4/NF-κB/NEAT1. Galectin-3 and TLR4 expression are abnormally up-regulated in lung adenocarcinoma tissues, and positively correlated with NEAT1 expression. CONCLUSION: We confirmed that Galectin-3 as a ligand of TLR4 induced TLR4 signaling activation in lung adenocarcinoma cells, thereby activating downstream p65 nucleus translocation, promoting NEAT1 expression, and finally affecting lung adenocarcinoma cell proliferation and migration. Inhibiting Galectin-3-induced TLR4 signaling activation, thus to reduce p65-activated NEAT1 expression might be a promising strategy of suppressing lung adenocarcinoma cell proliferation and migration.

[Treatment strategies for congenital heart disease in infants with severe pneumonia].

OBJECTIVE: To observe the results of different treatment of congenital heart disease (CHD) complicated with severe pneumonia in infants.
 Methods: A total of 27 infants with CHD and severe pneumonia were admitted to the Department of Pediatrics, Xiangya Hospital from January 2014 to December 2014, of whom 18 were male and 9 were female. The average age was 2.0-19.0(5.9±4.3) months, with an average body weight of 3.3-10.0 (5.8±1.8) kg. Infants were treated with a strategy of complete control of the lung infection before surgery (internal medicine group). From January 2015 to December 2015, 29 infants with same condition were admitted, of whom 15 were males and 14 females. The average age was 2.0-27.0 (6.1±3.9) months, with an average body weight of 3.1-8.0 (4.8±1.0) kg. Infants were treated with a strategy of combined treatment (combined treatment group), in which early surgical treatment were performed after a short time antibiotics and supportive treatment.
 Results: One nosocomial death in internal medicine group, with an average hospital stay for 3-26 (11±6) d. Further surgeries were performed in 5 patients after discharge with no surgical death. The mean preoperative hospital stay in combined treatment group was 1-21 (10±6) d. The mean total hospital stay for combined treatment group was 14-48 (24±9) d and the mean postoperative hospital stay was 6-35 (14±7) d. One patient died soon after surgery in combined treatment group. Thirty-day follow-up found that no other patient died in combined treatment group, and 6 patients died in internal medicine group. The 30-day mortality was 3.4% in combined treatment group and 22.2% in internal medicine group (P<0.01).
 Conclusion: Infant congenital heart disease complicated with severe pneumonia requires early surgical treatment, which contributed to the control of pulmonary infection and reduce mortality.

Pressure-Induced New Topological Weyl Semimetal Phase in TaAs.

We report a new pressure-induced phase in TaAs with different Weyl fermions than the ambient structure with the aid of theoretical calculations, experimental transport and synchrotron structure investigations up to 53 GPa. We show that TaAs transforms from an ambient I4_{1}md phase (t-TaAs) to a high-pressure hexagonal P-6m2 (h-TaAs) phase at 14 GPa, along with changes of the electronic state from containing 24 Weyl nodes distributed at two energy levels to possessing 12 Weyl nodes at an isoenergy level, which substantially reduces the interference between the surface and bulk states. The new pressure-induced phase can be reserved upon releasing pressure to ambient condition, which allows one to study the exotic behavior of a single set of Weyl fermions, such as the interplay between surface states and other properties.

Hydrogel-Reactive-Microenvironment Powering Reconfiguration of Polymer Architectures.

Reconfiguration of architected structures has great significance for achieving new topologies and functions of engineering materials. Existing reconfigurable strategies have been reported, including approaches based on heat, mechanical instability, swelling, origami/kirigami designs, and electromagnetic actuation. However, these approaches mainly involve physical interactions between the host materials and the relevant stimuli. Herein, a novel, easy-manipulated, and controllable reconfiguration strategy for polymer architectures is proposed by using a chemical reaction of host material within a hydrogel reactive microenvironment. 3D printed polycaprolactone (PCL) lattices transformed in an aqueous polyacrylamide (PAAm) hydrogel precursor solution, in which ultraviolet (UV) light triggered heterogeneous grafting polymerization between PCL and AAm. In situ microscopy shows that PCL beams go through volumetric expansion and cooperative buckling, resulting in transformation of PCL lattices into sinusoidal patterns. The transformation process can be tuned easily and patterned through the adjustment of the PCL beam diameter, unit cell width, and UV light on-off state. Controlling domain formation is achieved by using UV masks. This framework enables the design, fabrication, and programming of architected materials and inspires the development of novel 4D printing approaches.

Myocardial Priority Promotes Cardiovascular Recovery for Acute Type A Aortic Dissection Combined with Coronary Artery Disease Undergoing Aortic Arch Surgery.

The optimal surgical strategy for acute type A aortic dissection (ATAAD) with coronary artery disease (CAD) remains unclear. The goal of this study was to investigate the cardiovascular protective effects of the myocardial priority (MP) strategy or traditional selective cerebral perfusion (SCP) in ATAAD with CAD. A total of 214 adults were analyzed retrospectively, of which 80 underwent the MP strategy intraoperatively. Seventy-nine pairs were propensity-score-matched and divided into SCP and MP groups. The follow-up period ranged from 6 to 36 months. The MP group had a significantly shorter myocardial ischemic time, higher perfusion flow, higher radial artery pressure, and lower incidence of NIRS decrease >20% of the base value, but a longer lower limb circulatory arrest and bypass time than the SCP group. Although similar adverse cardiac and cerebrovascular events were observed in both groups, a shorter posthospital stay, less blood loss and transfusion, higher postoperative hemoglobin, lower creatinine, and higher PaO2/FiO2 were observed in the MP group. Subgroup analysis showed that when the TIMI Risk Score was <4, the MP group had a lower incidence of low cardiac output and lower postoperative cTnI level. The follow-up patients had similar morbidities between the two groups. The novel MP strategy is associated with a shortened myocardial ischemic time, better maintained perfusion of vital organs, and postoperative recovery after surgery for ATAAD combined with non-severe CAD.

Review on Fatigue of Additive Manufactured Metallic Alloys: Microstructure, Performance, Enhancement, and Assessment Methods.

Additive manufacturing (AM), which is a process of building objects in a layer-upon-layer fashion from designed models, has received unprecedented attention from research and industry because it offers outstanding merits of flexibility, customization, reduced buy-to-fly ratio, and cost-effectiveness. However, the fatigue performance of safety-critical industrial components fabricated by AM is still far below that obtained from conventional methods. This review discusses the microstructural heterogeneities, randomly dispersed defects, poor surface quality, and complex residual stress generated during the AM process that can negatively impact the fatigue performance of as-printed parts. The difference in microstructural origin of fatigue failure between conventionally manufactured and printed metals is reviewed with particular attention to the effects of the trans-scale microstructures on AM fatigue failure mechanisms. Various methods for mitigating the fatigue issue, including pre-process, inter-process, and post-process treatments, are illustrated. Empirical, semi-empirical, and microstructure-sensitive models are presented to predict fatigue strength and lifetime. Summary and outlooks for future development of the fatigue performance of AM materials are provided.

Association of preoperative monocyte/lymphocyte ratio with postoperative oxygenation impairment in patients with acute aortic syndrome.

BACKGROUND: Postoperative oxygenation impairment represents a common complication in patients with the acute aortic syndrome (AAS). The study aimed to explore the relationship between inflammatory indicators and AAS patients with oxygenation impairment after operation. METHODS: In this study, 330 AAS patients who underwent surgery were enrolled and divided into 2 groups based on postoperative oxygenation impairment (non-oxygenation impairment group and oxygenation impairment group). Regression analysis was performed to assess the relationship between inflammatory indicators and postoperative oxygenation impairment. A smooth curve and interaction analysis were further conducted. Stratified analysis was used according to preoperative monocyte/lymphocyte ratio (MLR) (Tertiles). RESULTS: Multivariate analysis showed that preoperative MLR was independently related to oxygenation impairment after surgery in AAS patients (OR, 95% CI, P: 2.77, 1.10-7.00, 0.031). The smooth curve indicated the risk of postoperative oxygenation impairment was higher with the elevated preoperative MLR. Interaction analysis revealed that patients with AAS with high preoperative MLR who had coronary artery disease (CAD) had a higher risk of oxygenation impairment after operation. Moreover, stratified analysis was performed according to baseline MLR (Tertiles), and a higher baseline MLR level in AAS patients was correlated with a lower arterial oxygen tension (PaO2) / inspiratory oxygen fraction (FiO2) ratio perioperatively. CONCLUSIONS: In AAS patients, preoperative MLR level was independently related to postoperative oxygenation impairment.

Compact pulse generator with sub-nanosecond rise time based on inductance of order of several nH.

Pulse generators with a sub-nanosecond rise time are typically used to calibrate measurement probes in electromagnetic pulses. However, the technological dilemma between high voltage and low inductance has not been adequately addressed in this context. In this paper, the authors investigate the effects of the circuit and structural parameters on the generator. To reduce the rise time of the output voltage of the generator to a few hundred picoseconds, the inductance of its structure and the spark gap needs to be strictly controlled. We use SF6 at 1 MPa as an insulating gas for the spark gap to reduce the inductance of the capacitor and the switch to the order of several nH. The results of theoretical calculations and simulations were used to design and test two generators that used a coaxial ceramic capacitor and three plate ceramic capacitors, respectively. The experimental results showed that a double-exponential pulse voltage with a sub-nanosecond rise time could be obtained in a 50 Ω transmission line in both generators. The generator with the coaxial ceramic capacitor had better characteristics than the one that used three plate ceramic capacitors with a rise time of 630-860 ps when the peak output voltage was in the range of 5-30 kV.