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This paper investigates the three-dimensional spatial characteristics of graphite in compacted graphite iron (CGI), at different crystallization stages, by interrupting the solidification process through experimental technique and taking three-dimensional X-ray diffraction (XRD) images through contrast tomography technique. The nucleation, growth mechanism and degeneration of graphite were analyzed by electron probe microanalysis technique (EPMA), scanning electron microscope with energy disperse spectroscopy (SEM-EDS), and transmission electron microscopes (TEM). The relationship between the maximum volume, connectivity and duration of crystallization was established by the analysis of the growth dynamics. The results have established a further relationship of nucleation between compacted graphite and spheroidal graphite. It was confirmed that the nucleation of graphite in CGI has a mechanism identical to that in the spherical graphite iron. The investigation proves that Ce2S3, La2S3, and Ti2S3 have nucleation capacity and that the growth mechanism of compacted graphite involves the evolution from spheroidal to cluster-like and then to interconnected graphite. The investigation also proves that the formation of compacted graphite is based on the graphite growth and graphite degeneration, which finally forms a worm-like morphology. According to the analysis of growth dynamics, the connectivity can be used as a key index for the CGI graphite nodularity and will affect the comprehensive properties of the material such as strength, thermal fatigue, thermal conductivity. The results are expected to provide a better understanding of compacted graphite iron as well as a better enrichment of the nucleation and growth mechanism of CGI.

Steinernema populi n. sp. was recovered by baiting from beneath poplar trees in China. Morphological and molecular features provided evidence for placing the new species into the Kushidai clade. The new species is characterized by the following morphological features: third-stage infective juveniles (IJ) with a body length of 1095 (973–1172) μm, a distance from the anterior end to excretory pore of 77 (70–86) μm and a tail length of 64 (55–72) μm. The Body length/Tail length (c) ratio and Anterior end to Excretory pore/ Tail length × 100 (E%) of S. populi n. sp. are substantially greater than those of all other ‘Feltiae–Kushidai–Monticolum’ group members. The first-generation males can be recognized by a spicule length of 66 (57–77) μm and a gubernaculum length of 46 (38–60) μm. The new species is further characterized by sequences of the internal transcribed spacer and partial 28S regions of the ribosomal DNA. Phylogenetic analyses show that Steinernema akhursti and Steinernema kushidai are the closest relatives to S. populi n. sp.

The rapid development of shortform video in the new media era has become a new opportunity for the development of the Internet. At the same time, the homogeneity and vulgarity of shortform video have become serious. “Idyllic” shortform video has gained a huge following on shortform video platforms. The thesis analyzes why “idyllic” shortform video is popular both in the West and East, and provides ideas of “nature” aesthetics, micronarrative strategy, and modern anxieties about those videos.

The microstructure, tensile strength, high-cycle fatigue property and corresponding damage mechanisms of compacted graphite iron at room temperature (25 °C), 400 °C and 500 °C, were investigated. It is found that the fatigue strength increases at first and then decreases with the increase of the testing temperature. At 25 °C, the fatigue crack mainly initiates from graphite debonding and propagates along the graphite clusters. At 400 °C, the fatigue crack initiation is influenced by oxidation; the fatigue strength may be improved by dynamic strain aging. At 500 °C, the oxidation becomes more serious and the oxide layer accelerates the crack to propagate along the matrix. At the same time, the phenomenon of grain boundary softening, one of the reasons resulting in the reduction of fatigue strength, appears. Then, the model of damage mechanism was proposed according to the propagation behavior of fatigue crack at high temperatures, and the quantitative relationship between the fatigue strength and the ratio of the interphase corrosion depth to the critical crack length was established. This investigation may enrich the fundamental understanding on the damage mechanism of compacted graphite iron.

Purpose Extracorporeal membrane oxygenation (ECMO) is used as a bridge for the sickest patients awaiting heart transplantation (HT). Herein, we report on six-month post-transplant survival in patients bridged with ECMO in the year before (PRE) and after (POST) the implementation of the updated UNOS Policy allocation system (October 18, 2018). Methods We identified 172 (PRE, N = 27, POST, N-145) adult patients in the UNOS registry that underwent heart transplantation from ECMO during the year before and after UNOS policy change. Baseline clinical characteristics were compared using Mann-Whitney U test and Chi-square test as appropriate. Survival analysis was performed using Kaplan-Meier analysis. Univariate and Multivariate Cox Proportional Hazards (PH) regression was performed as well. Results There was no difference in baseline clinical characteristics or hemodynamics before and after the policy change. Notably, there was a greater than 5-fold increase in ECMO utilization as a bridge to heart transplantation in the POST era. Distance from donor to recipient hospital (28 mi [7.0-271 mi] vs 261 mi [99-404 mi], p Conclusion Despite longer ischemic times and a greater distance between donor and recipient hospitals, six-month, post-transplant survival in patients bridged to heart transplant with ECMO improved after the UNOS policy change.

Purpose The 2018 UNOS Heart Allocation policy changes aimed to improve stratification in patients receiving heart transplant. Patients receiving inotropes who were classified as status 1A were re-classified as status 3 following the changes. We sought to assess the effect of the 2018 UNOS Heart Allocation policy changes on patients receiving inotropes. Methods 1569 patients who required inotropes received HT in the year before and after the UNOS policy changes. Pre- (n=831) and post-policy (n=738) cohorts were identified using the UNOS registry. Baseline characteristics were compared using standard statistical analysis. 180-day outcomes were evaluated using Kaplan Meier survival analysis as well as univariate and multivariate Cox proportional hazards modeling. Results Baseline characteristics were similar for both groups regarding age, gender, ethnicity, diabetes status, smoking history, non-transplant cardiac surgery history, ventilator use, serum creatinine, PA mean pressure, and cardiac output but differed in IABP use at transplant (pre: 10%, post: 48.5%, p Conclusion UNOS policy changes were not shown to affect HT survival 180 days for patients receiving inotropes prior to transplant, however mean ischemic time and days on waiting list were increased, as well as IABP use. Further research is warranted to determine if these factors will affect patient mortality moving forward.

Purpose The 2018 UNOS heart allocation policy change was intended to prioritize sicker patients while also improving waitlist outcomes. Here, we investigate competing outcomes of patients waitlisted one year before and after this policy change (10/18/2018). Methods Patients on the waitlist for heart transplant were identified through the UNOS registry one year before (PRE, n=3,924) and after (POST, n=3,825) the UNOS policy change. Baseline characteristics were compared using Mann-Whitney U test and Chi-square test as appropriate. Competing outcomes analysis was performed to compare (1) death or deterioration, (2) heart transplant or recovery, or (3) continuation on waitlist at 6 months. . Results At 180 days, patients in the POST group showed decreased waitlist death or deterioration (5.25% vs 6.37%, p=0.035), greater proportion of transplant or recovery (56.6% vs 48.4%, p Conclusion Following the policy change, there was a reduction in death or deterioration on the waitlist and an increase in the proportion of patients undergoing heart transplantation or experiencing myocardial recovery. Additional analysis is needed to better understand factors contributing to these improved outcomes and longer term implications of this policy change.

Purpose Advanced amyloid cardiomyopathy (ACM) patients have high waitlist (WL) mortality. Given the greater emphasis and clarity for status exceptions for ACM patients in the new allocation system, we sought to assess whether this change in the allocation policy would affect the WL and post-transplant outcomes in ACM pts. Methods Thirty-five patients were identified in the UNOS database that underwent heart transplant (HT) with a prior diagnosis of ACM during a 6-month period immediately before and after the policy change. Comparisons between patient characteristics in the pre (n=24) and post (n=11) policy-change cohorts are reported using standard statistical methods; survival analysis was performed using Cox proportional hazards modeling. Results The WL statuses of the pre patients were 1A (n=15), 1B (n=5), 2 (n=4) while the WL statuses of the post patients were 2 (n=7), 3 (n=2), 4 (n=2). The recipient age, donor age, gender, ethnicity, diabetes status, and ischemic time were similar for both groups. Total days on WL for pre and post were similar (26.0 days vs 29.0 days, p=0.82). The use of IABP was greater following the policy change (55% post vs 4% pre, p Conclusion The heart allocation policy change did not significantly decrease wait list times in ACM patients awaiting heart transplant, however there was significant greater utilization of pre-transplant IABP use. There were overall fewer patients that underwent HT in the 6 months following implementation of the new system, and there was no observed difference in 6-month post-HT survival for patients with ACM in the new allocation system.

Purpose We report the long-term survival of heart transplant (HT) patients with a diagnosis of Chagas cardiomyopathy. Methods The UNOS database was queried for HT candidates with a pre-transplant diagnosis of Chagas cardiomyopathy (1987-2019). Post-HT survival was followed over the ensuing 120 months. Demographics, comorbidities, hemodynamics were compared using standard statistical methods. Multivariate Cox-proportional hazard regression analysis (adjusted for age, sex, diabetes, ethnicity, ischemic time, dialysis, life support and HLA mismatch) was also performed for survival analysis. Results 38 patients with Chagas cardiomyopathy received HT. The Chagas group tended to be older recipients (Mean 52.6 ± 8.2 vs. 46.7 ± 19.2 years, p=0.053) and have older donors (Mean 28.2 ± 14.0 vs. 32.4 ± 11.2 years, p=0.063). Ethnic composition was significantly different (p Conclusion Long-term survival after HT in carefully selected patients with a diagnosis of Chagas cardiomyopathy is shown to be favorable as compared to that of non-Chagas patients. The proportion of patients with this disease may be underestimated and their increased recognition is prudent given the adverse consequences to Chagas reactivation post-HT.

Purpose In October 2018, the United Network for Organ Sharing (UNOS) implanted changes to its adult heart allocation policy. Under this new policy, hospitalized heart transplant (HT) candidates on inotropic therapy who were previously defined as status 1A were re-classified as status 3. Our aim was to assess the short-term outcomes of this re-classification for hospitalized patients on inotropes in a national dataset. Methods The UNOS database was queried for HT candidates who required inotropes prior to transplantation during a six-month period pre policy change as Status 1A (N=367) and post (N=108) policy change as Status 3. Patient demographics, comorbidities, mechanical circulatory support (MCS) requirements, and post-HT mortality were compared using standard statistical methods. Cox proportional hazards modeling was used to compare six-months survival between the two groups. Results Mean age, gender, diabetes status, and history of prior cardiac surgery were similar across both groups. There were also no significant differences in mean donor age or ischemic time. The median time (with IQR) on the waiting list was significantly shorter following the policy change [21.5 (8.0, 44.0), 36.0 (14.0, 79.0), p Conclusion The heart allocation policy change significantly decreased waitlist times in patients bridged to HT with inotropes, but had a significantly worse 6-month post-HT survival. This surprising finding will need to be better evaluated in future studies.

Purpose Postpartum cardiomyopathy (PPCM) is a prevalent cause of end-stage heart failure in women, from which about 10% will require heart transplantation. We aimed to further evaluate long-term heart transplant (HT) outcomes in this cohort of patients and compare them to all other heart transplant recipients. Methods The UNOS registry was queried for all cardiac transplants in the registry from 1987 to 2019 to compare characteristics and outcomes for PPCM-patients and all other HT patients. Hazard ratios (HR) were calculated using multivariate Cox proportional hazard regression analysis. Survival curves were generated with the Kaplan Meier method. Results Between 1987 and 2019, 63,142 patients received a heart transplant. Of these patients, 666 women had a heart transplant in which the indication was PPCM. These patients tended to be younger (p 20% (22.2% vs. 9.4%, p Conclusion Despite being a younger cohort with less chronic medical issues, PPCM had worse survival compared to non-PPCM patients with increased sensitization as well as increased use of IABP and VAD support. Further study is warranted to address these findings.

Purpose HCM patients may have increased waitlist (WL) mortality. Given the recent change in prioritizing patients with restrictive and hypertrophic cardiomyopathy requiring mechanical support, we sought to assess whether the policy change would affect the waitlist and post-transplant outcomes in HCM pts. Methods 59 pts were identified in UNOS registry that underwent heart transplant (HT) with a diagnosis of HCM during a 6-month period immediately before and after the UNOS policy change. Comparisons between pt characteristics in the pre (n=43) and post (n=16) policy-change cohorts are reported using standard statistical methods; survival analysis performed using Cox proportional hazards modeling. Results The WL statuses of the pre-policy change pts were 1A (n=22), 1B (n=11), 2 (n=10) while the WL statuses of the post pts were 1 (n=2), 2 (n=7), 3 (n=1), 4 (n=6). For both groups, the age, donor age, gender, ethnicity, DM status, and ischemic times were similar. The median wait list time was decreased following the policy change (24.5 vs. 43 days, p=0.01). There was greater use of IABP following the allocation system change (31% vs. 5%, p=0.01). There was a trend toward worse post-HT survival in HCM following the policy change (p=0.06). Conclusion The policy change significantly decreased waiting times for HCM pts on the HT list with a trend towards increased mortality with decreased rates of transplant. Further study is warranted to understand the long-term implications of this policy change.

Purpose Heart transplant recipients may be at increased risk for infection and adverse outcomes from infection with coronavirus (Covid-19). Management of these patients is complex, with no standard of care. We sought to describe the incidence and outcomes of coronavirus infection in this unique population. Methods Retrospective review of 225 heart transplant patients at a large academic medical center identified 8 patients with laboratory confirmed Covid-19 infection. Laboratory and clinical data were collected from our institution as well as other local hospitals patients had been treated at. Outcomes were followed from March 15, 2020 to October 15, 2020. All data was deidentified. Results In a cohort of 225 heart transplant patients, 8 patients were identified after testing positive for Covid-19 infection. The mean and median age of patients was 49.8 and 42 years respectively. 63% of patients were male, and 37% of patients were female. The median and mean time from transplant to diagnosis was 4.1 and 4.5 years. The rate of infection for recently transplanted patients was 11%. Two patients (25%) had atherosclerosis, three patients (37.5%) had diabetes, and five patients (62.5%) had hypertension. Four of the patients (50%) were asymptomatic, 3 patients (37.5%) had acute hypoxic respiratory failure, and 1 patient (12.5%) had dyspnea not requiring oxygen at time of presentation. Four patients (50%) were admitted for treatment. Two patients were treated with remdesvir, one patient with tocilizumab, and one patient with lenrolimab. Immunosuppressive regimens were altered in five patients with decreased mycophenolate mofetil dosing, two patients with decreased tacrolimus dosing, and one patient with decreased cyclosporine dosing. Two patients (25%) had evidence of graft injury with mean AlloSure (donor derived cell free DNA) of 0.6%, the remainder were within normal limits. Overall our patient experience resulted in zero mortality, and all 4 admitted patients were discharged home safely. Conclusion In a single center case series 8 patients were identified with Covid-19 infection. 25% of the patients demonstrated evidence of graft injury, and nearly every patient had their immunosuppressive regimen decreased with 100% survival to date. Further investigation is needed to determine long term outcomes and ideal therapeutic regimen for Covid-19 in this unique population.

Purpose The UNOS Policy change in 2018 reclassified all adult CHD patients as status 4, as this patient population is not as well supported by inotropes or other forms of mechanical support which would normally increase a patient's status. We performed an analysis of competing outcomes in patients on the waitlist one year before (PRE) and after (POST) this policy change (10/18/2018). Methods Patients with CHD on the waitlist for heart transplant were identified through the UNOS database one year before (PRE, n=149) and after (POST, n=166) the UNOS policy change. Baseline characteristics were compared using Mann-Whitney U test and Chi-square test as appropriate. Competing outcomes analysis was performed to compare (1) death or deterioration, (2) heart transplant or recovery, or (3) continuation on waitlist at 6 months. Results At 180 days, a greater proportion of POST patients were transplanted (50.0% vs 40.3%, p=0.026). There was no significant difference in death or deterioration (7.38% vs 7.23%, p=0.97), or continuation on waitlist (52.4% vs 42.8%, p=0.138). Patients in POST had fewer days on the waitlist (110.5, IQR 29.5-296.8 vs 171, IQR 73.0-453.0, p Conclusion After the policy change, a greater proportion of CHD patients were transplanted or recovered, with a shorter amount of time on the waitlist. There was no difference in death or deterioration or continuation on the waitlist at 6 months. Further study is warranted, including analysis by congenital heart disease type, in order to further assess the efficacy of the policy change.

Purpose The intent of the UNOS allocation system change was to better prioritize heart transplantation (HT) for the most critically ill patients. Here, we explore six-month post-transplant survival of HT patients one year before (PRE) and after (POST) the allocation change (10/18/2018). Methods We identified all adult patients (N=3776) that underwent HT between 10/18/2017 to 10/17/2019. There were 1741 patients in the PRE group and 2035 in the POST group. Baseline clinical characteristics were compared using Mann-Whitney U test and Chi-square test as appropriate. Survival analysis was performed using Kaplan-Meier analysis and both Univariate and Multivariate Cox Proportional Hazards (PH) regression analysis adjusted for policy change, recipient age, donor age, bilirubin, creatinine, dialysis use, ischemic time, ventilator use, and ECMO use. Results There was a significant reduction in six-month survival in the POST vs. PRE group (92% vs 94%, p=0.04). On univariate analysis, the policy change was a significant predictor of mortality (HR 1.30 [1.02, 1.67]), however on multivariate analysis significance was lost (HR 1.16 [0.90, 1.50]). Median ischemic time (3.5 hrs vs. 3.0 hrs, p Conclusion There was a small, but significant reduction in six-month post-transplant survival following implementation of the policy change. Policy change was a significant predictor of mortality on univariate analysis, but significance was lost on multivariate analysis.

Purpose Impella is used as a bridge for heart transplantation (HT) in unstable patients. We sought to compare baseline characteristics and 6-month post-transplant survival in patients who utilized impella as a bridge to HT in the one year before and after the UNOS allocation policy change. Methods We queried the UNOS database for all adult heart transplant recipients that were bridged to heart transplantation with an Impella device (n=90). Exclusion criteria included patients who were younger than 18 years old, lost to follow-up, or who had multi-organ transplant were excluded. Pre-policy era (n=25) and post-policy era (n=65) baseline characteristics were compared via standard statistical analysis, reported in median and IQR. Kaplan Meier survival analysis and univariate cox regression were performed. Multivariate cox proportional hazard (PH) regression analysis was adjusted for age, donor age, recipient creatinine and bilirubin at the time of heart transplantation, dialysis, and ischemic time. Results There was no difference in baseline characteristics between groups. The post policy change was associated with increased ischemic time (3.8 vs 2.8 hours, p=0.01) and increased distance from donor and recipient hospitals (248 vs 36 nautical miles, p=0.01). UNOS policy change was not a significant predictor of post-transplant mortality on either unadjusted (p >0.9) or adjusted (p>0.9) Cox PH modeling. Conclusion The distance between donor hospital to transplant center was farther, and ischemic time was longer in the post-era policy change. In spite of this, overall mortality was unchanged.

Purpose The 2018 UNOS heart allocation policy change was intended to prioritize sicker patients while also improving waitlist outcomes. We sought to compare competing outcomes for patients bridged to heart transplantation using Impella devices one year prior to and after the UNOS Allocation Policy change in October 2018. Methods The UNOS database was queried for all adult patients in whom an Impella device (CP/5.0) was used as a bridge to heart transplantation in the 12 month period before and after the UNOS policy change. 28 patients in the pre-policy change and 56 patients in the post-policy change were supported with Impella and underwent heart transplantation. Patients who were younger than 18 years old, lost to follow-up, or who had multi-organ transplant were excluded. Baseline characteristics were compared using Mann-Whitney U test and Chi-square test as appropriate. Competing outcomes analysis was performed to compare (1) death or deterioration, (2) heart transplant or recovery, or (3) continuation on waitlist at 6 months. Results There were no differences between the pre- and post-allocation change groups in regards to recipient age, donor age, gender, ethnicity, ischemic time, and serum creatinine at time of transplant, and hemodynamics. Patients in the post-policy change group had greater rates of transplantation (76.7% vs 39.3%, p Conclusion Impella devices were used more frequently in the one year after the allocation policy change. Early after the UNOS allocation policy change, patients bridged with Impella were more likely to be transplanted however with no difference in waitlist mortality. Additional analysis is needed to better understand whether these results will persist over time as more patients are transplanted with Impella support.

As an ideal material for the cylinder head of high power density diesel engine, vermicular graphite cast iron (VGI) with higher thermal conductivity was received more and more attention recently. In this article, finite element (FE) software ANSYS was applied to investigate the changes of thermal conductivity of VGI with the vermicularity and the FE-models are carried out based on the real metallographic images of VGI. The results indicate that there is a big difference between the numerical simulation and the reality without the consideration of the thermal contact resistance of interface between matrix and graphite. The numerical simulation result is close to the reality when the contact thermal conductance is set at 0.1 W/(m2·K). In addition, the equivalent thermal conductivity along X direction kequ,x rises from 34.437 W/m·K to 38.902 W/m·K and increases by 13% or so when the vermicularity is improved from 40% to 90% according to the numerical simulation. Keywords: Vermicular graphite cast iron, Thermal conductivity, Contact thermal conductance, Vermicularity, Finite element

Composited ceramic coating was successfully deposited on a cast piston Al–Si system alloy ZAl12Si3Cu2NiMg using plasma electrolytic oxidation (PEO) process, and the coating mechanism that focused on the initial stages was studied systematically. The morphology, composition and microstructure of the PEO coating were analysed in detail by combination of scanning electron microscopy with energy dispersive X-ray system and X-ray diffraction. The results show that the PEO process involved three stages. The anodic oxide films were simultaneously formed on α-Al phase and eutectic Si in the initial first stage of PEO treatment, but no plasma discharge occurred on primary bulk Si phase. Both primary and eutectic Si phases prevented aluminium oxidisation and had great effects on the morphology and composition of coatings at the first stage. When voltage exceeded 300 V, plasma discharge appeared and concentrated on the localised zone of interface between α-Al and Si phase, and Al–Si–O compound formed. The silicon wa...

A novel austenite-martensite dual-phase steel with a ductility of ~30% and tensile strength over 1.4 GPa was developed. The hard martensite in the dual phase steel was strengthened through precipitation strengthening by Cu/NiAl precipitates, forming the maraging phase. The deformation mechanisms of the steel were investigated using in situ neutron diffraction and transmission electron microscopy (TEM). The results indicate that the maraging phase constrains the deformation of soft austenite, forming a strong skeleton frame with the soft austenite involved in the frame. The yield strength was controlled by the deformation of hard maraging phase, leading to the high strength of the steel. The plasticity of the maraging phase was improved through the synchronously deformation and rotation of martensite grains along with the frame-structure effect. During deformation of the maraging phase, the transfer of the dynamic stress and strain from the hard phase to a soft one compels the cooperative deformation of the soft phase together with the hard phase. This deformation contributes further to the ductility through the transformation-induced plasticity (TRIP) effects of the soft austenite. Furthermore, the cooperative deformation and the dynamic stress/strain partitions can effectively suppress the strain localization at the phase interface, retarding the crack initiation.

Purpose The availability of hepatitis C (HCV) antiviral therapy has made transplantation of HCV NAT+ donor hearts a new reality, expanding the pool of donor organs. We report the utilization and outcomes of transplantation of HCV NAT positive (HCV NAT+) hearts recorded in the United Network for Organ Sharing (UNOS) database. Methods 11,252 heart transplant (HT) patients with HCV NAT status were reported by UNOS (2010-2019), of which 274 received an HCV NAT+ donor organ. Survival was evaluated at 24 months post HT. Demographics, comorbidities, hemodynamics were compared using standard statistical methods. Multivariate Cox-proportional hazard regression analysis (adjusted for age, sex, diabetes, ethnicity, ischemic time, dialysis, life support and HLA mismatch) was also performed for survival analysis. Results 274 patients received heart transplantation from HCV NAT+ donors. No significant difference in survival was identified at 24 months post-transplant (NAT + vs. -: 16.7% vs. 9.3%, p=0.70) despite longer allograft ischemic times in the HCV NAT+ group. HCV NAT+ recipients were older (Mean 53.6 ± 12.7 vs. 55.4 ±11.7 years, p=0.01) and also had older donors (Mean 32.1 ± 11.1 vs. 33.6 ± 8.1 years, p=0.02). Additionally, HCV NAT+ recipients had shorter median waitlist times (Median [inter-quartile range], 86.5 [18.0, 254.0] vs. 100.0 [29.0, 301.0], p=0.002). Multivariate analysis yielded a hazard ratio of 0.87 (CI 0.51-1.48) comparing NAT + to NAT - recipients. Conclusion Intermediate survival post-transplantation is similar between HCV NAT+ and HCV NAT- recipients. Expansion of the donor pool via the inclusion of HCV NAT+ donors may shorten waitlist times and may extend donor organ availability.

Purpose The recent change in the UNOS heart allocation policy was intended to prioritize heart transplantation (HT) for the sickest patients based on hemodynamic (HD) criteria and the need for temporary mechanical circulatory support (tMCS). Patients meeting HD criteria and requiring veno-arterial extra-corporeal membrane oxygenation (VA-ECMO) for circulatory support are designated as Status 1. Here, we report on 6-month outcomes and patient characteristics before and after the implementation of the heart allocation policy change in patients bridged to HT with VA-ECMO. Methods 60 patients were identified in the UNOS database that were bridged to HT with VA-ECMO during a six-month period immediately before and after the policy change. Comparisons between patient characteristics in the pre (N=28) and post (N=32) policy-change cohorts are reported using standard statistical methods; survival analysis was performed using Cox proportional hazards modeling. Results Mean age was greater in the post-policy change group (46.1 ± 18.0 vs 34.6 ± 24.8 years, p=0.042). Median (interquartile range) time on the wait list was significantly shorter following the policy change [32.0 (14.0, 90.5) days vs 4.0 (2.0, 16.5) days, p Conclusion The heart allocation policy change significantly decreased wait-list times in patients bridged to HT with VA-ECMO without any observed difference in 6-month post-HT survival.

Purpose Myocarditis is a known etiology of both acute fulminant heart failure and chronic dilated cardiomyopathy requiring heart transplantation. We sought to evaluate the long-term post-transplant outcomes of pts with myocarditis. Methods We evaluated the UNOS registry for all heart transplant (HT) recipients from 1987 to 2019. Comparisons between pt characteristics of HT recipients with myocarditis (N=649) and HT recipients without a diagnosis of myocarditis (N=62,493) are reported using standard statistical methods including Cox proportional hazards regression for survival analysis. Results Myocarditis HT recipients were younger (29.6 ± 20.7 vs. 46.8 ± 19.1, p Conclusion Myocarditis HT recipients tend to be a younger population with less underlying co-morbidities such as DM and prior cardiac surgery, but they are more likely to be more acutely sick at the time of heart transplantation requiring mechanical ventilation, ECMO, or VAD support. Myocarditis HT recipients have shorter organ wait times and have more favorable transplant related factors, and ultimately have a lower overall mortality compared to recipients without myocarditis.

Purpose The recent change in the UNOS heart allocation policy was intended to prioritize heart transplant (HT) for the sickest patients, and thus sought to prioritize illness severity by dividing the heterogeneous population encompassed in the prior Status 1A category to the more discrete Status 1-3 categories. We explored the 6-month post-HT outcomes and patient characteristics before and after the implementation of this policy change in the sickest, hospitalized patients awaiting HT. Methods 1,667 patients were identified in UNOS that were either Status 1A in the prior classification system or Status 1 - 3 in the new policy during a 6-month period immediately before and after the policy change. Comparisons between patient characteristics in the pre-policy change Status 1A (N=988) and post policy-change Status 1-3 (N=679) cohorts are reported using standard statistical methods; Kaplan-Meier survival analysis and multivariate analysis using Cox proportional hazards modeling was performed. Results Mean age was greater in the new Status 1-3 group (53.4 ± 12.9 vs. 39.7 ± 25.1, p Conclusion The UNOS heart allocation policy change for new Status 1-3 patients was associated with increased post-HT mortality compared with the prior Status 1A patients at 6 months. This was despite shorter organ wait times and higher IABP use. Further studies are warranted to understand the long-term implications of this policy change.

Purpose The advent of anti-viral therapy for HBV has made it possible to expand the donor pool for heart transplant recipients. Little is known in long term outcomes of recipients who receive HBV+ donor hearts. We sought to explore long-term transplant outcomes in recipients who received HBV+ donor hearts compared to those who received HBV- donor hearts. Methods UNOS registry was queried and identified 1,141 patients who received a heart transplant from hepatitis B core antibody (HBcAb)+ donors and 53,192 patients who received a heart transplant from HBcAb- donors. Multivariate Cox proportional hazard regression analysis was adjusted for age, sex, diabetes, ethnicity, ischemic time, dialysis, life support, waitlist time and HLA mismatch. Kaplan-Meier survival curves were generated comparing survival outcomes in patients post-HT with HBcAb+ donor to patients post-HT with HBcAb- donor. Results There were 1141 patients in the donor HBV+ cohort and 53,192 patients in the donor HBV- cohort. HBV+ cohort were younger (p Conclusion Use of HBV+ donors in heart transplantation was associated with worse overall survival compared to use of HBV- donors. Further study is warranted to better understand the implications of these findings.

Purpose Cardiac sarcoidosis (CS) is a known etiology of both end-stage dilated and restrictive cardiomyopathy requiring heart transplantation. We sought to evaluate the long-term post-transplant outcomes of patients with CS compared to patients without CS. Methods We evaluated the United Network of Organ Sharing (UNOS) registry for all heart transplant (HT) recipients from 1987 to 2019. Comparisons between patient characteristics of HT recipients with CS (N=288) and HT recipients without a diagnosis of CS (N=62,854) were reported using standard statistical methods including Cox proportional hazards regression for survival analysis. Results Sarcoid HT recipients were significantly older (52.4 ± 9.0 vs. 46.6 ± 19.2, p Conclusion Cardiac sarcoidosis HT recipients tended to be an older population with less underlying co-morbidities such as diabetes and prior cardiac surgery. They were more likely to receive older donors. Although sarcoid HT recipients have similar organ wait times as non-CS recipients, they ultimately have a lower overall mortality.

Purpose We report the trends in utilization and outcomes of intra-aortic balloon pump (IABP) as a bridge to heart transplantation (HT) in the six-month period immediately before and after the implementation of the revised United Network of Organ Sharing (UNOS) allocation system in October 2018. Methods The UNOS database was queried for HT candidates who required temporary mechanical circulatory support with IABP who were transplanted within a 6-month time window before (N=125) and after (N=193) the UNOS allocation change. Demographics, comorbidities, hemodynamics, and post-HT mortality were compared using standard statistical methods. Multivariate Cox proportional hazard regression analysis (adjusted for age, sex, diabetes, ethnicity, ischemic time, dialysis, life support and HLA mismatch) was also performed for survival analysis. Results Mean age between the before and after groups, respectively, was similar (54.8 ± 12.0 vs. 54.2 ± 13.2 years, p=0.7). No significant differences were identified in recipient demographics, comorbidities, renal function or invasive hemodynamics at time of transplantation. There were no statistically significant differences in donor age or donor organ ischemic time. Total waitlist time was lower in the post-policy change group (median [inter-quartile range], 10.0 [5.0, 26.0] vs. 31.0 [11.0, 87.0] days; p Conclusion The number of HT candidates on IABP at the time of HT has increased following implementation of the new UNOS allocation system with a concurrent reduction in candidate waitlist time, but no difference in post-HT mortality.

Purpose Marfan syndrome (MS) is an autosomal dominant connective tissue disorder that causes a defect in the gene fibrillin-1. MS patients develop advanced cardiomyopathies, in which previous studies have demonstrated the presence of a discrete cardiomyopathy associated with MS. Given the vascular complications associated with MS and unclear impact immunosuppression may have on systemic vascular disease, little evidence guides suitability of patients with MS for heart transplant. We sought to investigate long-term heart transplant outcomes of patients with MS listed in the UNOS registry. Methods The UNOS database was queried for all cardiac transplants in the registry from 1987 to 2019 to compare characteristics and outcomes of patients with MS and all other heart transplant patients. Hazard ratios (HR) were calculated using multivariate Cox proportional hazard regression analysis. Survival curves were generated with Kaplan Meier method. Results Between 1987 and 2019, 22 patients with MS were listed for a heart transplant with a mean age of 35.0 ± 16.3 years. Most patients were male (73%) and Caucasian (73%). Patients with MS were more likely to have prior cardiac surgery (non-transplant) compared to all other heart transplant patients (54.5% vs. 18.3%, p Conclusion Survival of Marfan patients was comparable to non-Marfan patients despite increased surgical complexity and greater association with prior cardiac surgery. While further study is warranted, heart transplant is a suitable treatment option in patients with Marfan syndrome and advanced heart failure.

Purpose Contrary to prior practice, human immunodeficiency virus (HIV) positive status is no longer a contraindication to heart transplantation (HT) in many centers due to demonstrated satisfactory outcomes post-HT. However, knowledge about the long-term outcomes post-HT of this cohort is limited. We characterized the long-term post-HT outcomes of HIV+ patients compared to HIV- patients. Methods A total of 59,796 HT patients were analyzed from the UNOS registry from 1987 to 2019, of which 76 were HIV+. Characteristics of HT patients with and without HIV infection were compared using standard statistical methods. Multivariate Cox proportional hazard regression analysis was performed for survival analysis. Results The mean age and gender between the HIV+ and HIV- HT recipients were comparable. HIV+ patients were less likely to have undergone prior cardiac surgery (65.8% vs 79.1%, p=0.004). In terms of transplant-related factors, HIV+ HT recipients had a trend towards receiving older donors (p=0.06) but had similar ischemic times. At the time of HT, HIV+ patients more frequently required intra-aortic balloon pump (IABP) (11.8% vs 5.5%, p=0.016) and ventricular assist device (VAD) support (47.4% vs 26.7%, p Conclusion Post HT survival of HIV+ recipients was similar to HIV- recipients despite greater acuity as demonstrated by the increased use of IABP and VADs. Therefore, HT is a feasible and safe option for carefully selected HIV+ recipients. Further study is warranted to understand long-term implications.

Purpose Smoking cessation is a prerequisite prior to listing for HT, however the optimal duration of smoking cessation prior to listing is unknown and there is variability amongst HT programs on an acceptable abstinence period. We sought to evaluate the long-term post-transplant outcomes of patients based on duration of smoking cessation. Methods We evaluated the UNOS registry for all HT recipients from 2005 to 2019. We compared patient characteristics in the group with smoking cessation duration less than or equal to 12 months from the time of listing (N=2800) to the group with cessation duration greater than 12 months (N=9524). The differences were analyzed using standard statistical methods including Cox proportional hazards regression for survival analysis. Results Recipient mean age (57.3 ± 9.9 vs 50.5 ± 11.8, p 12 month group. Diabetes (33.1% vs. 24.0%, p 12 month group. Recipients were less likely to require ventricular assist device (VAD) support (43.4% vs. 50.2%, p 12 month group. Median (IQR) time on the wait list was significantly longer for the >12 month group [97.0 (29.0, 264.0) days vs. 81.0 (25.0, 231.0) days, p 12 month group (p Conclusion Despite being an older group with higher prevalence of diabetes, prior cardiac surgery, higher donor age, and longer organ wait time, patients with longer (>12 month) duration of smoking cessation have improved survival post-HT with less need for ventilator and VAD support. These findings may have implications for patient selection.

Purpose We sought to elucidate the differences in outcomes between patients undergoing Heart-Lung (HL) Heart-Lung-Kidney (HLK) and Heart-Lung-Liver (HLL) multiorgan transplantation. Methods Using the UNOS registry, we compared outcomes in HL, HLK, and HLL recipients. Analysis was performed using multivariate Cox proportional hazard regression model that adjusted for age, sex, race, diagnosis of diabetes, ischemic time, recipient wait-time, HLA mismatch, need for dialysis, and need for life support. We excluded patients who were age less than 18 years old or who were lost-to-follow-up. Kaplan-Meier survival analysis was performed. Results 1177 HL patients, 8 HLK, and 12 HLL patients were identified. HL recipients were more likely to have undergone prior non-transplant cardiac surgery (HL 91.6% vs HLK 75.0% vs HLL 75.0% p=0.033). HLK patients were more likely to require VAD support (HL 1.2% vs HLK 12.5% vs HLT 0.0% p=0.015), have higher serum creatinine (HL 1.0 mg/dL ± 0.6 vs HLK 2.4 ± 1.3 vs HLL 0.9 ± 0.5 p Conclusion Despite increasing risk factors, HL concomitant with either kidney or liver transplant did not affect survival compared to HL alone. Carefully selected patients may benefit from triple organ transplantation, however, ethical issues of organ utilization may arise.

Purpose The change in the UNOS heart allocation policy was intended to prioritize the sickest patients first and put forth stringent hemodynamic (HD) criteria to justify use of temporary mechanical circulatory support (tMCS). Patients meeting HD criteria and requiring tMCS with veno-arterial extra-corporeal membrane oxygenation (VA-ECMO) receive the highest priority (Status 1) and includes extended donor organ sharing. Herein, we report on the association between time spent on VA-ECMO and post-heart transplantation (HT) outcomes following the UNOS policy change. Methods The UNOS registry was queried for all patients on VA-ECMO in the 6-months following the UNOS allocation policy change. A total of 32 patients were bridged to HT with VA-ECMO. Patients were divided into short- (N=24) and long- (N=8) duration groups based on time on VA-ECMO support, while listed as Status 1, using a cutoff of 5-days. Clinical, laboratory, hemodynamic, and ischemic time were compared with standard statistical methods and between-group mortality was assessed with Cox proportional hazards modeling. Results Median age was similar between the short- (32.6 ± 12.9) and long- (30.9 ± 10.6) duration groups, p=0.38. Median number of days on VA-ECMO while listed as Status 1 was 2.0 (2.0, 3.5) days versus 7.0 (5.5, 11.0) days with 24/32 (75%) successfully bridged to HT in less than five days. The short-duration group spent a total median (interquartile range) time on VA-ECMO support of 2.5 (2.0, 4.0) days compared to 26.5 (11.5, 52.5) days. There were no differences in renal function, hemodynamics, or need for dialysis at the time of transplant. Additionally, there was no difference in mean donor age or ischemic time. There was a trend towards better survival in the short-duration VA-ECMO group versus the long-duration group (p=0.097) Conclusion A majority of patients listed as Status 1 and supported with VA-ECMO undergo HT within a 5-day period. There is a suggested association of better survival with shorter duration of VA-ECMO support while listed as Status 1, but more analysis is needed to establish this. More analysis is required to identify factors leading to longer duration on VA-ECMO support.

The microstructure evolution of Mg–6 wt% Gd–2 wt% Y alloy (denoted as GW62) during solid solution and aging process were investigated by optical microscope, scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction and high resolution transmission electron microscopy. The microstructure of as-cast GW62 alloy is comprised of isometric α(Mg) crystals, equilibrium phase Mg 5 (Gd,Y), and non-equilibrium phase Mg 2 (Gd,Y). With the increase of solution treatment time, the sizes of the semicontinuous Mg 5 (Gd,Y) phases gradually decrease until dissolved. Rare-earth-rich phases (Mg(Gd,Y) 2 ) with fcc structures a =0.56 nm were newly generated in the alloy at grain boundaries and inside grains after solution treatment, which could hinder the growth of isometric α(Mg) crystals in the solution process. The maximum hardness of the GW62 alloy is significantly different for different aging temperatures. The age-hardening effect is most apparent at 175 °C. The microstructural evolution of the alloy after aging at 175 °C was as follows: the β″ phase precipitated from α(Mg) during the under-aging stage (4–32 h); next, the β′ phase precipitated from α(Mg) up until peak aging was reached (32–100 h); as aging time progressed, the hardening reached its maximum at 100 h. At this stage, the precipitated phases were the β′ and β″ phases; finally, during over-aging (>100 h), the size of β′ phase continually increased while transforming into the β 1 and β phases.

An in situ amide hydrosilylation reaction was developed to prepare polyamide 12 (PA12)/polysiloxane copolymers by reactive blending. This reaction is focused on the addition of hydrogenosilane groups (SiH) from polysiloxane to the carbonyl group from the PA12 amide function. To evidence this carbonyl hydrosilylation onto an amide based polymer, an approach on model compounds (use of N -methylpropionamide) was carried out. The mechanism and kinetics were investigated with multinuclear NMR ( 1 H, 13 C and 29 Si). During kinetics studies, the concentration of N -silylated copolymers can reach 70 mol% after 2 h reaction at 100 °C. Amide hydrosilylation reaction was extended to the reactive blending of polyamide 12 with PDMS-SiH under molten processing conditions. Formation of a structured blend was investigated by rheology and electronic microscopy at different scales. The impact of both shearing and reaction on the final morphology was deeply studied and the interfacial enhancement by compatibilization was confirmed. As a result, the dispersion of PDMS domains decreased from 3 to 4 μm to around 0.8 μm in diameter forming submicronic morphology. Furthermore, it was possible to control the dispersion of PDMS at different scales by modifying the physico-chemical parameters (molar mass and functionality) of both components.

The magnetic control tunable characteristics of localized modes of One-dimensional Cantor quasicrystal structure containing nanoparticle magnetic fluid is studied by using the transfer matrix method. First, the physical model of One-dimensional Cantor quasicrystal structure containing nanoparticle magnetic fluid is built. Then, the transmission spectrum of One-dimensional Cantor quasicrystals structure containing nanoparticle magnetic fluid is calculated by transfer matrix method. Finally, the magnetic control tunable characteristics of localized modes are discussed. The results show that the generation of One-dimensional Cantor quasicrystal structure containing nanoparticle magnetic fluid increased, the number of localized modes increased as well; the wavelength of localized modes shift to the long-wave direction with the refractive index of magnetic fluid increasing; the higher generation, the higher of the quality factor of the split localized modes; the wavelength drift variation decreases with the increasing of localized modes level at the same generation.