A single-center experience of type B aortic intramural hematoma.

OBJECTIVE: The outcomes of the best medical treatment (BMT) and intervention treatment (INT) in a single-center experience were reported in type B intramural hematoma (IMH). METHODS: From February 2015 to February 2021, a total of 195 consecutive patients with type B IMH were enrolled in the study. The primary end point was mortality, and the secondary end points included clinical and imaging outcomes. The clinical outcomes were aortic-related death, retrograde type A aortic dissection, stent graft-induced new entry tear, endoleak, and reintervention. The imaging outcome was evaluated through the latest follow-up computed tomography angiography, which included aortic rupture, aortic dissection, aortic aneurysm, rapid growth of aortic diameter, newly developed or enlarged penetrating aortic ulcer or ulcer-like projection (ULP) and increased aortic wall thickness. Kaplan-Meier curves were used to assess the association between different treatments. RESULTS: Among the enrolled patients, 115 received BMT, and 80 received INT. There was no significant difference in early (1.7% vs 2.5%; P = 1.00) and midterm all-cause death (8.3% vs 5.2%; P = .42) between the BMT and INT groups. However, patients who underwent INT were at risk of procedure-related complications such as stent graft-induced new entry tear and endoleaks. The INT group was associated with a profound decrease in the risk of ULP, including newly developed ULP (4.3% vs 26.9%; P < .05), ULP enlargement (6.4% vs 31.3%; P < .05), and a lower proportion of high-risk ULP (10.9% vs 45.6%; P < .05). Although there was no significant difference in the incidence of IMH regression between the two groups, the maximum diameter of the descending aorta in patients receiving INT was larger compared with those treated with BMT. CONCLUSIONS: Based on our limited experience, patients with type B IMH treated with BMT or INT shared similar midterm clinical outcome. Patients who underwent INT may have a decreased risk of ULPs, but a higher risk of procedure-related events and patients on BMT should be closely monitored for ULP progression.

Incidence, Predictors, and Implications of Secondary Aortic Intervention Following Thoracic Endovascular Aortic Repair for Type B Dissection.

BACKGROUND: Secondary aortic intervention (SAI) following thoracic endovascular aortic repair (TEVAR) is not uncommon. However, a satisfactory management system has not been established for these patients. We aimed to report our single-center experience with SAI after prior TEVAR for type B aortic dissection (TBAD). METHODS: From January 2010 to May 2017, 860 eligible patients with TBAD underwent TEVAR. One hundred seven (12.4%) patients required SAI, either endovascularly (n=76) or surgically (n=31). The main indications for SAI were entry flow (n=58 [54.2%]), aneurysm expansion of the proximal or remote aorta (n=26 [24.3%]), retrograde type A aortic dissection (n=11 [10.3%]), distal stent-graft-induced new entry tear (n=6 [5.6%]), and stent migration (n=4 [3.7%]). The Kaplan-Meier curves were generated to determine the degree of freedom from SAI and the prognosis. Cox proportional hazards were used to screen for risk factors for SAI and poor prognosis. RESULTS: The overall 30-day mortality rate after SAI was 4.7% (n=5): endovascular (n=2 [2.6%]) vs open surgery (n=3 [9.7%]; p=0.145). The cumulative survival rates with or without SAI were 86.3%±3.6% vs 95.7%±0.8% at 3 years and 82.0%±4.2% vs 92.2%±1.1% at 5 years, respectively (log-rank p<0.001). Although no significant difference in survival was observed, the incidence of SAI was significantly greater in patients who underwent TEVAR during the chronic phase (acute [11.6%] vs subacute [9.6%] vs chronic [27.8]; p<0.001). Multivariate regression analysis revealed that prior TEVAR in the chronic phase (hazard ratio [HR]=1.73, 95% confidence interval [CI]=1.03-2.90; p=0.039), maximum aortic diameter (HR=1.05, 95% CI=1.04-1.07; p<0.001), and arch involvement (HR=1.48, 95% CI=1.01-2.18; p=0.048) were predictors of the incidence of SAI. In addition, the maximum aortic diameter was demonstrated to be the only risk factor for prognosis after adjusting for confounding factors. CONCLUSIONS: Thoracic endovascular aortic repair for chronic TBAD patients should be reconsidered. Open surgery is preferable for those with proximal progression, whereas endovascular treatment is more suitable for distal lesions. Close surveillance and timely reintervention after TEVAR, whether via endovascular techniques or open surgery, are necessary to prevent devastating complications. CLINICAL IMPACT: The management of patients with type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR) is challenging. We summarized our single-center experience regarding secondary aortic intervention after TEVAR for TBAD. We found that TEVAR for chronic TBAD patients should be carefully evaulated, and open surgery is recommended for those with proximal progession, while endovascular treatment is more preferable for distal lesions.

Optimal medical treatment versus endovascular aortic repair in uncomplicated isolated abdominal aortic dissection.

OBJECTIVE: To report the results of optimal medical treatment (OMT) and endovascular aortic repair (EVAR) in patients with uncomplicated isolated abdominal aortic dissection (IAAD). METHODS: A retrospective review of 96 consecutive patients with uncomplicated IAAD (uIAAD) managed at a single tertiary vascular unit between January 2011 and July 2021 was conducted. Standard methods for univariate and survival analyses were used. The primary outcomes were all-cause mortality. Secondary end points included uIAAD progression, interventional complications, and follow-up aortic intervention. RESULTS: Initially, 53.1% of patients (51/96) were managed with OMT. No in-hospital deaths occurred. During follow-up, three patients died, and three and two patients who were initially managed with OMT subsequently required endovascular treatment and surgical management, respectively. Initially, 46.9% of patients (45/96) underwent EVAR. One patient died during hospital admission; nine patients had an endoleak after operation and one needed reintervention. Furthermore, during follow-up, five patients died; four patients needed reoperation, one surgery and three endovascular treatments. The overall long-term mortality was 8.4%, and follow-up aortic intervention rate was 9.5% (median follow-up, 54 months; interquartile range, 33-81 months) with no significant difference between groups. Of note, 12 patients (12.6%) suffered uIAAD progression, which was higher in the OMT group than EVAR group (10 [19.6%] vs 2 [4.5%]; P = .03). CONCLUSIONS: uIAAD may be managed safely by OMT with regular surveillance, despite the risk of disease progression. Compared with OMT, EVAR could significantly prevent uIAAD progression. For anatomically suitable patients with uIAAD progression and who are unresponsive to OMT, pre-emptive EVAR is a safe and feasible option.

Feasibility and safety of Stanford A aortic dissection complete endovascular repair system in a porcine model.

BACKGROUND: Acute type A aortic dissection (ATAAD) is a catastrophic disease with high morbidity and mortality. Although open surgery is still the gold standard for the treatment of ATAAD, some patients, with advanced age and multiple comorbidities, can only receive medical management alone. Nowadays, thoracic aortic endovascular repair (TEVAR) provides a potential treatment option for the patient with ATAAD, but traditional stent grafts (SGs), which are not designed for the ATAAD, are inapplicable to the unique anatomy of the aortic arch. Therefore, we innovatively created the BRIDGE system (Chuangxin Medical, Shenzhen, China), a complete endovascular reconstruction system designed to treat ATAAD. This study aimed to evaluate the feasibility and safety of the novel Stanford A aortic dissection complete endovascular reconstruction system in a porcine model. METHOD: The BRIDGE system consists of the type A stent system and the type C stent system. Between November 2020 and March 2021, three white swine were utilized in the study. The BRIDGE system was deployed via the transcatheter approach under angiographic guidance. The swine(n = 3) treated with our system were evaluated using angiography before sacrifice 1-month after implantation, which was followed by gross specimen evaluation and histological examination of harvested tissues. RESULT: The acute procedure success rate was 100% (3/3). The immediate post-procedural angiography showed that both type A SGs and type C SGs were deployed in satisfactory locations, with patency of the supra-aortic trunk and no endoleak. The cumulative mortality of 30-day was 0% without any adverse events. No device migration or leakage was observed angiographically, before sacrifice. The gross observation confirmed a type A SG covered part of the entry of anonyma. Favorable endothelialization, no thrombogenesis, and slight inflammatory infiltration of the tissues around the device were confirmed by microscopic examinations in all pigs. CONCLUSION: It was feasible and secure to use Stanford A aortic dissection complete endovascular reconstruction system to implement a transcatheter endovascular repair in a porcine model. With this novel system, treating acute type A aortic dissection may be more efficient and secure in human.

Association between the non-HDL-cholesterol to HDL- cholesterol ratio and abdominal aortic aneurysm from a Chinese screening program.

BACKGROUND: Abdominal aortic aneurysms (AAAs) can result in high mortality upon rupture but are usually undiagnosed because of the absence of symptoms in the early stage. Ultrasound screening is regarded as an impactful way to prevent the AAA-related death but cannot be performed efficiently; therefore, a target population, especially in Asia, for this procedure is lacking. Additionally, although dyslipidaemia and atherosclerosis are associated with AAA. However, it remains undetermined whether the non-high-density lipoprotein-cholesterol to high-density lipoprotein-cholesterol ratio (NHHR) is associated with AAA. Therefore, this study was aimed at examining whether NHHR is associated with AAA. METHOD: A total of 9559 participants who underwent AAA screening at Guangdong Provincial People's Hospital and through screening in two communities in Dongguan, from June 2019 to June 2021 joined in this screening program. The diagnosis of AAA was confirmed by the ultrasound examination of the abdominal aorta rather than any known or suspected AAA. Clinical and laboratory data of participants were collected. The participants were separated into a normal group and an AAA group according to the abdominal aortic status. To eliminate confounding factors, a propensity score matching (PSM) approach was utilized. The independent relationship between NHHR and AAA was assessed through the utilization of multivariable logistic regression analysis. In addition, internal consistency was evaluated through subgroup analysis, which controlled for significant risk factors. RESULTS: Of all the participants, 219 (2.29%) participants were diagnosed with AAA. A significant elevation in NHHR was identified in the AAA group when contrasted with that in the normal group (P < 0.001). As demonstrated by the results of the multivariable logistic regression analysis, AAA was independently associated with NHHR before (odds ratio [OR], 1.440, P < 0.001) and after PSM (OR, 1.515, P < 0.001). Significant extension was observed in the areas under the receiver operating characteristic curves (AUROCs) of NHHR compared to those of single lipid parameters before and after PSM. An accordant association between NHHR and AAA in different subgroups was demonstrated by subgroup analysis. CONCLUSION: In the Chinese population, there is an independent association between NHHR and AAA. NHHR might be propitious to distinguish individuals with high risk of AAA.

Efficacy of epi-1 modified epirubicin and curcumin encapsulated liposomes targeting-EpCAM in the inhibition of epithelial ovarian cancer cells.

Treatment of epithelial ovarian cancer (EOC) is a challenge because it still leads to unsatisfactory clinical prognosis. This is due to the toxicity and poor targeting of chemotherapeutic agents, as well as metastasis of the tumor. In this study, we designed a targeted liposome with nanostructures to overcome these problems. In the liposomes, epirubicin and curcumin were encapsulated to achieve their synergistic antitumor efficacy, while Epi-1 was modified on the liposomal surface to target epithelial cell adhesion molecule (EpCAM). Epi-1, a macrocyclic peptide, exhibits active targeting for enhanced cellular uptake and potent cytotoxicity against tumor cells. The encapsulation of epirubicin and curcumin synergistically inhibited the formation of neovascularization and vasculogenic mimicry (VM) channels, thereby suppressing tumor metastasis on SKOV3 cells. The dual drug loaded Epi-1-liposomes also induced apoptosis and downregulated metastasis-related proteins for effective antitumor in vitro. In vivo studies showed that dual drug loaded Epi-1-liposomes prolonged circulation time in the blood and increased the selective accumulation of drug at the tumor site. H&E staining and immunohistochemistry with Ki-67 also showed that targeted liposomes elevated antitumor activity. Also, targeted liposomes downregulated angiogenesis-related proteins to inhibit angiogenesis and thus tumor metastasis. In conclusion, the production of dual drug loaded Epi-1-liposomes is an effective strategy for the treatment of EOC.

Systemic immune-inflammation index predicted the clinical outcome in patients with type-B aortic dissection undergoing thoracic endovascular repair.

BACKGROUND: The systemic immune-inflammation index (SII) has been reported to have prognostic ability in various cardiovascular diseases; however, it has not been studied in type-B aortic dissection (TBAD). We aimed to explore the relation of SII with short-term and long-term outcomes in TBAD patients undergoing thoracic endovascular repair (TEVAR). METHODS: We performed a retrospective analysis of a prospectively maintained database from 2010 to 2017. The patients were divided into two groups (high SII and low SII) as per the optimal cut-off value determined using the receiver operating characteristic curve. Multivariate logistic and Cox regression analyses were performed to analyse the relationship between the SII and the short-term and long-term outcomes. RESULTS: A total of 805 TBAD patients who underwent TEVAR were enrolled. Twenty-six (3.2%) patients died during hospitalisation. At the end of a median follow-up duration of 48.80 mon, 70 (9.8%) patients had died. The patients were divided into the high-SII group [n = 333 (41.4%%)] and the low-SII group [n = 472 (58.6%)] as per the optimal cut-off value of 1,062. Multivariable logistic analyses showed that a high-SII score was independently associated with major adverse cardiovascular events (MACEs) in-hospital (odd ratio [OR], 1.67; 95% confidence interval [CI], 1.13-2.47; p = .01). In addition, multivariable Cox analyses showed that a high-SII score could be an independent indicator for follow-up adverse events (hazard ratio [HR], 1.70; 95% CI, 1.14-2.56, p = .01). CONCLUSIONS: Systemic immune-inflammation index is associated with both in-hospital and long-term outcomes in patients with TBAD undergoing TEVAR. Therefore, SII may serve as valuable tool for risk stratification before intervention.

Management and Outcomes of Non-A Non-B Aortic Dissection.

OBJECTIVE: The results of best medical treatment (BMT), endovascular based treatment (EBT), and total arch replacement (TAR) with frozen elephant trunk (FET) treatment in a single centre experience were reported in non-A non-B aortic dissection patients. METHODS: From January 2016 to May 2020, 215 consecutive patients with acute or subacute non-A non-B aortic dissection were enrolled. The primary endpoints were all cause death. Secondary endpoints included follow up adverse aortic event (AE), a composite of the outcomes of dissection related death, rupture, retrograde type A aortic dissection, stent graft induced new entry tear, secondary endoleak, and follow up re-intervention. Kaplan-Meier curves were used to evaluate associations between different treatments and outcomes. RESULTS: Among the 215 dissection patients, 127 (59.1%) received EBT, 42 (19.5%) received TAR + FET, and the remaining 46 (21.4%) received BMT. Thirty day mortality was higher in patients receiving TAR + FET (7.1%) than in those treated with EBT (1.6%) or BMT (2.2%) (p = .12). However, after a median follow up of 39.1 (27.0 - 50.7) months, no additional death was recorded in the TAR + FET group, while nine (7.3%) patients died in the EBT group and 14 (31.8%) died in the BMT group (p < .001). Specifically, EBT and TAR + FET showed no significant difference in midterm mortality rate, follow up AE, and re-intervention for complicated or uncomplicated dissection patients involving zone 2. For patients with uncomplicated non-A non-B aortic dissection involving zone 2, EBT could profoundly decrease the mortality rate, follow up AE and re-intervention when compared with BMT (p < .010 for all), although this difference was not statistically significant between TAR + FET and BMT. No statistical comparison was performed in patients with zone 1 involvement because of the limited number of patients. CONCLUSION: It was demonstrated that EBT or TAR + FET might be a viable strategy for non-A non-B aortic dissection patients.

Association between platelet counts and morbidity and mortality after endovascular repair for type B aortic dissection.

This study aimed to assess the association of postoperative platelet counts with early and late outcomes after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). We retrospectively evaluated 892 patients with TBAD who underwent TEVAR from a prospectively maintained database. Postoperative nadir platelet counts were evaluated as a continuous variable, and a categorical variable (thrombocytopenia), which was defined as platelet count≤ the lowest 10% percentile (108 × 109/l). Multivariable logistic regression analyses were conducted to assess the impact of postoperative thrombocytopenia on early outcomes, and multivariable cox regression analyses on long-term mortality. Patients with postoperative thrombocytopenia experienced significantly higher rates of postoperative mortality, prolonged intensive care unit stay, death, stroke, limb ischemia, mesenteric ischemia, acute kidney injury (AKI), and puncture-related hematoma (P< .05 for each), but similar rates of immediate type I endoleak and spinal cord ischemia. Multivariable logistic analyses showed that postoperative thrombocytopenia was independently associated with postoperative stroke, limb ischemia, and AKI. Similar results were observed when postoperative nadir platelet count was modeled as a continuous predictor (P< .05 for each). By multivariable Cox analyses, postoperative thrombocytopenia was an independent predictor for long-term all-cause mortality (hazard ratio 2.72, 95% CI, 1.72-4.29, P< .001). For every 30 × 109/L decrease in postoperative platelet count, the risk of long-term all-cause mortality increased by 15% (HR 1.15; 95% CI 1.07-1.25; P< .001). Therefore, postoperative thrombocytopenia might be a useful tool for risk stratification after TEVAR.

Timing and Outcome of Endovascular Repair for Uncomplicated Type B Aortic Dissection.

OBJECTIVE: This study aimed to determine the effect of intervention timing, from symptom onset to thoracic endovascular aortic repair (TEVAR), on early and late outcomes in high risk patients with uncomplicated type B aortic dissection (uTBAD). METHODS: The study retrospectively evaluated 267 uTBAD patients with high risk radiographic features who underwent pre-emptive TEVAR during the acute and subacute periods. Demographics, comorbidities, pre-operative imaging features, peri-procedural details, and follow up outcomes were analysed. RESULTS: Among the 267 pre-emptive TEVARs for high risk uTBAD, 130 were performed in the acute phase (1-14 days); and 137 in the subacute phase (15-90 days), from initial presentation. The mean age was 55.9 ± 11.0 years and 222 (83.1%) were men. The 30 day mortality rate in the acute group was five times higher than that in the subacute group (3.8% vs. 0.7%), although without statistically significant difference (p = .11). No statistically significant difference in 30 day outcomes (aortic rupture, retrograde type A dissection [RTAD], immediate type Ia endoleak, stroke, spinal cord ischaemia, and re-intervention) was noted (p > .05 for each). Of note, aortic rupture, RTAD, and disabling stroke were observed only in the acute group. Multivariable logistic analyses showed that intervention timing was not associated with 30 day outcomes. The median clinical follow up was 48.2 ± 25.9 months (range 1 - 106 months). There were no significant differences in all cause mortality, dissection related death, late intervention, or aortic related late events among timing cohorts (p > .05 for each). Furthermore, aortic remodelling, by analysing the flow status of the false lumen and evaluation of aortic diameters, either at the thoracic aorta level or the abdominal aorta level, was similar between the two groups. Multivariable Cox analyses showed that intervention timing was not associated with late outcomes. CONCLUSION: The present study indicates that TEVAR for high risk uTBAD in the acute phase was associated with a trend toward higher rates of early complications, while the long term outcomes were comparable with those of the subacute phase.

First-principles investigation of oxygen interaction with hydrogen/helium/vacancy irradiation defects in Ti3AlC2.

First-principles calculations have been performed to investigate the interaction between solute impurity O and H/He/vacancy irradiation defects in Ti3AlC2. The formation energy and occupation of O atoms within different defects as well as the trapping progress of O/H clusters are discussed. It is found that the O atom preferentially occupies the hexahedral interstitial site (Ihex-1) in bulk Ti3AlC2, whereas it prefers to occupy the neighbouring tetrahedral interstitial site (Itetr-2) within pre-exisiting Al monovacancy (VAl), Al divacancy (2VAl-Al) and the 2VAl-C divacancy composed of Al and C vacancies. The appearance of C vacancy could greatly reduce the oxygen formation energy and make an O atom more inclined to occupy the center of C vacancy. Vacancy could capture more O atoms than H/He atoms, where VAl and 2VAl-Al could hold up to fifteen and eighteen O atoms, respectively. Meanwhile, the O could also promote the formation of Al vacancy. On the other hand, O atoms tend to occupy the interstitial sites near the Al atomic layer and have attraction to Al atoms, which is likely to enable the O atoms to combine with the Al atoms to form a Al2O3 protective layer, thus effectively inhibiting further oxidation inside the Ti3AlC2. In addition, the H-O exhibits repulsion interaction, but strong attraction occurs in the He-O interaction. Therefore, the O atom has an inhibitory effect on the formation of the H cluster, while it could bind more He atoms to form a large number of He bubbles. Besides, the O impurity greatly reduces the trapping ability of vacancy to H atoms, and O and He have a synergistic interaction for inhibiting the aggregation of H clusters. The present results are expected to provide a new insight into the behaviour of Ti3AlC2 under irradiation and oxidation conditions so that structural materials could be better designed.

Prognostic dynamic nomogram integrated with metabolic acidosis for in-hospital mortality and organ malperfusion in acute type B aortic dissection patients undergoing thoracic endovascular aortic repair.

BACKGROUND: Organ malperfusion is a lethal complication in acute type B aortic dissection (ATBAD). The aim of present study is to develop a nomogram integrated with metabolic acidosis to predict in-hospital mortality and organ malperfusion in patients with ATBAD undergoing thoracic endovascular aortic repair (TEVAR). METHODS: The nomogram was derived from a retrospectively study of 286 ATBAD patients who underwent TEVAR from 2010 to 2017 at a single medical center. Model performance was evaluated from discrimination and calibration capacities, as well as clinical effectiveness. The results were validated using a prospective study on 77 patients from 2018 to 2019 at the same center. RESULTS: In the multivariate analysis of the derivation cohort, the independent predictors of in-hospital mortality and organ malperfusion identified were base excess, maximum aortic diameter ≥ 5.5 cm, renal dysfunction, D-dimer level ≥ 5.44 µg/mL and albumin amount ≤ 30 g/L. The penalized model was internally validated by bootstrapping and showed excellent discriminatory (bias-corrected c-statistic, 0.85) and calibration capacities (Hosmer-Lemeshow P value, 0.471; Brier Score, 0.072; Calibration intercept, - 0.02; Slope, 0.98). After being applied to the external validation cohort, the model yielded a c-statistic of 0.86 and Brier Score of 0.097. The model had high negative predictive values (0.93-0.94) and moderate positive predictive values (0.60-0.71) for in-hospital mortality and organ malperfusion in both cohorts. CONCLUSIONS: A predictive nomogram combined with base excess has been established that can be used to identify high risk ATBAD patients of developing in-hospital mortality or organ malperfusion when undergoing TEVAR.

New insight into the interaction between divacancy and H/He impurity in Ti3AlC2 using first-principles studies.

First-principles calculations have been conducted to investigate the interaction between vacancy defects and H/He impurity in Ti3AlC2. The formation energies of monovacancy and divacancy have been calculated. It is found that Al monovacancy (VAl), Al divacancy (2VAl-Al), and the divacancy composed of Al and C atoms (2VAl-C) are most easily formed in all vacancies. In addition, the interactions between multiple vacancies are weak. The formation of vacancy is relatively independent and not affected by other vacancies. The configurations and energies of H-mV (m = 0, 1, 2) complexes have been studied to assess the energetically favorable sites for H atoms. Within pre-existing VAl or 2VAl-Al, the most favorable site for H atoms is the Itetr-2 site, but the H atom tends to occupy the Ioct-4 site within 2VAl-C. The formation energies of the secondary vacancy defect nearest to an Al vacancy or C vacancy are significantly influenced by H impurity content. H clusters trapped in a primary Al vacancy can promote the formation of vacancy and prefer to form platelet-like bubbles parallel to the Al plane, while H clusters trapped in a primary C vacancy have higher probability to form spherical ones. The 2VAl-Al and 2VAl-C divacancies exhibit stronger H trapping ability than monovacancy. The 2VAl-Al divacancy could capture up to seven H atoms, and 2VAl-C could capture six H atoms. Meanwhile, the He-2VAl-Al complex could only capture four H atoms to form H-He hybridized bubbles, and He impurities effectively suppress further aggregation of H atoms. The present results provide microstructural images of nH-mV and nH-He-mV complexes as well as the evolution progress of H bubbles in Ti3AlC2, which is especially helpful for us to understand the behavior of H/He in Ti3AlC2 under irradiation.

A RhABF2/Ferritin module affects rose (Rosa hybrida) petal dehydration tolerance and senescence by modulating iron levels.

Plants often develop the capacity to tolerate moderate and reversible environmental stresses, such as drought, and to re-establish normal development once the stress has been removed. An example of this phenomenon is provided by cut rose (Rosa hybrida) flowers, which experience typical reversible dehydration stresses during post-harvest handling after harvesting at the bud stages. The molecular mechanisms involved in rose flower dehydration tolerance are not known, however. Here, we characterized a dehydration- and abscisic acid (ABA)-induced ferritin gene (RhFer1). Dehydration-induced free ferrous iron (Fe2+ ) is preferentially sequestered by RhFer1 and not transported outside of the petal cells, to restrict oxidative stresses during dehydration. Free Fe2+ accumulation resulted in more serious oxidative stresses and the induction of genes encoding antioxidant enzyme in RhFer1-silenced petals, and poorer dehydration tolerance was observed compared with tobacco rattle virus (TRV) controls. We also determined that RhABF2, an AREB/ABF transcription factor involved in the ABA signaling pathway, can activate RhFer1 expression by directly binding to its promoter. The silencing of RhABF2 decreased dehydration tolerance and disrupted Fe homeostasis in rose petals during dehydration, as did the silencing of RhFer1. Although both RhFer1 and Fe transporter genes are induced during flower natural senescence in plants, the silencing of RhABF2 or RhFer1 accelerates the petal senescence processes. These results suggest that the regulatory module RhABF2/RhFer1 contributes to the maintenance of Fe levels and enhances dehydration tolerance through the action of RhFer1 locally sequestering free Fe2+ under dehydration conditions, and plays synergistic roles with transporter genes during flower senescence.

Methyl Methacrylate HIPE Solely Stabilized by Fluorinated Di-block Copolymer for Fabrication of Highly Porous and Interconnected Polymer Monoliths.

Preparation of stable water-in-oil (W/O) high internal phase emulsion (HIPE) containing methyl methacrylate (MMA) monomer as oil phase is a difficult task due to the significant solubility of MMA in water. Here, for the first time a fluorinated di-block copolymer (FDBC) poly (2-dimethylamino)ethylmethacrylate-b-poly (trifluoroethyl methacrylate) (PDMAEMA-b-PTFEMA) is proposed to stabilize HIPEs of MMA without the use of any co-stabilizer or thickening agent. Fluorinated segments in FDBC anchored well at oil/water interface of HIPE, offering high hydrophobicity to the partially hydrophilic MMA monomer and in turn stabilization to MMA-HIPE. By using fluorinated di-block copolymer as stabilizer, highly stable HIPEs can be obtained. In addition, highly interconnected porous monoliths were obtained after free radical polymerization, which are highly desirable materials in various practical applications including tissue engineering scaffolds, separation science, bio-engineering and so on. The as-prepared MMA-HIPEs possess high thermal stability without phase separation. The textural characteristics of as-prepared composites, such as pore size and distribution, can be easily controlled by simply varying the amount of FDBC and/or dispersed phase fraction. Moreover, the influence of di-block concentration on water uptake (WU) capability of the prepared porous monoliths is explored.

Synergetic effect of H and He impurities in Ti3AlC2: first principles calculations.

First principles calculations have been performed to investigate the synergetic effect of H and He impurities with vacancies in Ti3AlC2. The configurations and energetics of Hn-He-VAl complexes (n ≤ 4) and He-He/He-H/H-H interactions have been studied. It is found that the impurity H atom prefers to occupy the tetrahedral interstitial site (Itetr-3), but the He atom prefers to occupy the octahedral interstitial site (Ioct-4) in perfect Ti3AlC2. Within a pre-existing Al vacancy, the most favorable site for a He atom is close to tetr-site, meanwhile the H atom preferentially deviates from the vacancy center with the separation 1.3 Å along the 001 direction. He-H and He-He show a weakly attractive interaction, but weak repulsion occurs in the H-H interaction, which is different from the case of Ti3SiC2. The He-VAl complex plays an important role in the trapping of H atoms. The He-VAl cluster can trap up to three H atoms in the absence of H2 molecules, which leads to the formation of a H-He hybridized bubble. Thus, the He atom can subsequently suppress further aggregation of H atoms and block hydrogen embrittlement and volume swelling.

Development and validation of an LC/MS/MS method for simultaneous determination of shionone and epi-friedelinol in rat plasma for pharmacokinetic study after oral administration of Aster tataricus extract.

A rapid and sensitive liquid chromatography tandem mass spectrometry (LC/MS/MS) method was developed and validated using spinasterol as the internal standard (IS) for the simultaneous determination of shionone and epi-friedelinol in rat plasma. Plasma samples were pretreated using liquid-liquid extraction with ethyl ether. Chromatographic separation was achieved on a C18 column (100 × 2.1 mm, 5 µm) with an isocratic elution consisting of acetonitrile-0.1% formic acid water (75:25, v/v) at a flow rate of 0.30 mL/min. Detection was performed under the selected reaction monitoring scan using an electrospray ionization in the positive ion mode. The mass transitions were as follows: m/z 427.4 → 95.1 for shionone, m/z 411.4 → 205.2 for epi-friedelinol and m/z 395.3 → 105.2 for IS. All calibration curves exhibited good linearity (r > 0.995) over the concentration range for both components. The intra- and inter-day precisions at three QC and lower limit of quantitation levels were both <10.21% in terms of relative standard deviation, and the accuracy ranged from -7.13 to 8.02% in terms of relative error. The extraction recoveries of the compounds ranged from 82.07 to 89.81%. The developed method was successfully applied to the pharmacokinetic study of shionone and epi-friedelinol after oral administration of Aster tataricus extract to rats. Copyright © 2015 John Wiley & Sons, Ltd.

RhHB1 mediates the antagonism of gibberellins to ABA and ethylene during rose (Rosa hybrida) petal senescence.

Rose (Rosa hybrida) is one of the most important ornamental plants worldwide; however, senescence of its petals terminates the ornamental value of the flower, resulting in major economic loss. It is known that the hormones abscisic acid (ABA) and ethylene promote petal senescence, while gibberellins (GAs) delay the process. However, the molecular mechanisms underlying the antagonistic effects amongst plant hormones during petal senescence are still unclear. Here we isolated RhHB1, a homeodomain-leucine zipper I transcription factor gene, from rose flowers. Quantitative RT-PCR and GUS reporter analyses showed that RhHB1 was strongly expressed in senescing petals, and its expression was induced by ABA or ethylene in petals. ABA or ethylene treatment clearly accelerated rose petal senescence, while application of the gibberellin GA3 delayed the process. However, silencing of RhHB1 delayed the ABA- or ethylene-mediated senescence, and resulted in higher petal anthocyanin levels and lower expression of RhSAG12. Moreover, treatment with paclobutrazol, an inhibitor of GA biosynthesis, repressed these delays. In addition, silencing of RhHB1 blocked the ABA- or ethylene-induced reduction in expression of the GA20 oxidase encoded by RhGA20ox1, a gene in the GA biosynthetic pathway. Furthermore, RhHB1 directly binds to the RhGA20ox1 promoter, and silencing of RhGA20ox1 promoted petal senescence. Eight senescence-related genes showed substantial differences in expression in petals after treatment with GA3 or paclobutrazol. These results suggest that RhHB1 mediates the antagonistic effect of GAs on ABA and ethylene during rose petal senescence, and that the promotion of petal senescence by ABA or ethylene operates through an RhHB1-RhGA20ox1 regulatory checkpoint.

Colchicine Blocks Abdominal Aortic Aneurysm Development by Maintaining Vascular Smooth Muscle Cell Homeostasis.

Development of non-surgical treatment of human abdominal aortic aneurysm (AAA) has clinical significance. Colchicine emerges as an effective therapeutic regimen in cardiovascular diseases. Yet, whether colchicine slows AAA growth remain controversy. Here, we demonstrated that daily intragastric administration of low-dose colchicine blocked AAA formation, prevented vascular smooth muscle cell (SMC) phenotype switching and apoptosis, and vascular inflammation in both peri-aortic CaPO4 injury and subcutaneous angiotensin-II infusion induced experimental AAA mice models. Mechanistically, colchicine increased global mRNA stability by inhibiting the METTL14/YTHDC1-mediated m6A modification, resulting in increased sclerostin (SOST) expression and consequent inactivation of the WNT/ß-catenin signaling pathway in vascular SMCs from mouse AAA lesions and in cultured human aortic SMCs. Moreover, human and mouse AAA lesions all showed increased m6A methylation, decreased SOST expression, and skewed synthetic SMC de-differentiation phenotype, compared to those without AAA. This study uncovers a novel mechanism of colchicine in slowing AAA development by using the METTL14/SOST/WNT/ß-catenin axis to control vascular SMC homeostasis in mouse aortic vessels and in human aortic SMCs. Therefore, use of colchicine may benefit AAA patients in clinical practice.