A whole-slide foundation model for digital pathology from real-world data.

Digital pathology poses unique computational challenges, as a standard gigapixel slide may comprise tens of thousands of image tiles1-3. Prior models have often resorted to subsampling a small portion of tiles for each slide, thus missing the important slide-level context4. Here we present Prov-GigaPath, a whole-slide pathology foundation model pretrained on 1.3 billion 256 × 256 pathology image tiles in 171,189 whole slides from Providence, a large US health network comprising 28 cancer centres. The slides originated from more than 30,000 patients covering 31 major tissue types. To pretrain Prov-GigaPath, we propose GigaPath, a novel vision transformer architecture for pretraining gigapixel pathology slides. To scale GigaPath for slide-level learning with tens of thousands of image tiles, GigaPath adapts the newly developed LongNet5 method to digital pathology. To evaluate Prov-GigaPath, we construct a digital pathology benchmark comprising 9 cancer subtyping tasks and 17 pathomics tasks, using both Providence and TCGA data6. With large-scale pretraining and ultra-large-context modelling, Prov-GigaPath attains state-of-the-art performance on 25 out of 26 tasks, with significant improvement over the second-best method on 18 tasks. We further demonstrate the potential of Prov-GigaPath on vision-language pretraining for pathology7,8 by incorporating the pathology reports. In sum, Prov-GigaPath is an open-weight foundation model that achieves state-of-the-art performance on various digital pathology tasks, demonstrating the importance of real-world data and whole-slide modelling.

Surgical choice for the treatment of partial intestinal ischemic necrosis caused by acute type a aortic dissection combined with malperfusion of superior mesenteric artery.

Acute type A aortic dissection is a severe cardiovascular disease characterized by rapid onset and high mortality. Traditionally, urgent open aortic repair is performed after admission to prevent aortic rupture and death. However, when combined with malperfusion syndrome, the low perfusion of the superior mesenteric artery can further lead to intestinal necrosis, significantly impacting the surgery's prognosis and potentially resulting in adverse consequences, bringing. This presents great significant challenges in treatment. Based on recent domestic and international research literature, this paper reviews the mechanism, current treatment approaches, and selection of surgical methods for poor organ perfusion caused by acute type A aortic dissection. The literature review findings suggest that central aortic repair can be employed for the treatment of acute type A aortic dissection with inadequate perfusion of the superior mesenteric artery. The superior mesenteric artery can be windowed and (/or) stented, followed by delayed aortic repair. Priority should be given to revascularization of the superior mesenteric artery, followed by central aortic repair. During central aortic repair, direct blood perfusion should be performed on the distal true lumen of the superior mesenteric artery, leading to resulting in favorable therapeutic outcomes. The research results indicate that even after surgical aortic repair, intestinal ischemic necrosis may still occur. In such cases, prompt laparotomy and necessary necrotic bowel resection are crucial for saving the patient's life.

Study on risk factors and treatment strategies of hypoxemia after acute type a aortic dissection surgery.

Acute type A aortic dissection is a life-threatening cardiovascular disease characterized by rapid onset and high mortality. Emergency surgery is the preferred and reliable treatment option. However, postoperative complications significantly impact patient prognosis. Hypoxemia, a common complication, poses challenges in clinical treatment, negatively affecting patient outcomes and increasing the risk of mortality. Therefore, it is crucial to study and comprehend the risk factors and treatment strategies for hypoxemia following acute type A aortic dissection to facilitate early intervention.

Overlooked shelf sediment reductive sinks of dissolved rhenium and uranium in the modern ocean.

Rhenium (Re) and uranium (U) are essential proxies in reconstructing past oceanic oxygenation evolution. However, their removal in continental shelf sediments, hotspots of early diagenesis, were previously treated as quantitatively unimportant sinks in the ocean. Here we examine the sedimentary reductive removal of Re and U and their coupling with organic carbon decomposition, utilizing the 224Ra/228Th disequilibria within the East China Sea shelf. We identified positive correlations between their removal fluxes and the rates of sediment oxygen consumption or organic carbon decomposition. These correlations enable an evaluation of global shelf reductive sinks that are comparable to (for Re) or higher than (~4-fold for U) previously established suboxic/anoxic sinks. These findings suggest potential imbalances in the modern budgets of Re and U, or perhaps a substantial underestimation of their sources. Our study thus highlights shelf sedimentary reductive removal as critical yet overlooked sinks for Re and U in the modern ocean.

CMOS Scaling for the 5 nm Node and Beyond: Device, Process and Technology.

After more than five decades, Moore's Law for transistors is approaching the end of the international technology roadmap of semiconductors (ITRS). The fate of complementary metal oxide semiconductor (CMOS) architecture has become increasingly unknown. In this era, 3D transistors in the form of gate-all-around (GAA) transistors are being considered as an excellent solution to scaling down beyond the 5 nm technology node, which solves the difficulties of carrier transport in the channel region which are mainly rooted in short channel effects (SCEs). In parallel to Moore, during the last two decades, transistors with a fully depleted SOI (FDSOI) design have also been processed for low-power electronics. Among all the possible designs, there are also tunneling field-effect transistors (TFETs), which offer very low power consumption and decent electrical characteristics. This review article presents new transistor designs, along with the integration of electronics and photonics, simulation methods, and continuation of CMOS process technology to the 5 nm technology node and beyond. The content highlights the innovative methods, challenges, and difficulties in device processing and design, as well as how to apply suitable metrology techniques as a tool to find out the imperfections and lattice distortions, strain status, and composition in the device structures.

STEAP3 promotes colon cancer cell proliferation and migration via regulating histone acetylation.

Colorectal cancer (CRC) is the third most prevalent diagnosed cancer in men and second most prevalent cancer in women. H3K27ac alterations are more commonly than gene mutations in colorectal cancer. Most colorectal cancer genes have significant H3K27ac changes, which leads to an over-expression disorder in gene transcription. Over-expression of STEAP3 is involved in a variety of tumors, participating in the regulation of cancer cell proliferation and migration. The purpose of this work is to investigate the role of STEAP3 in the regulation of histone modification (H3K27ac) expression in colon cancer. Bioinformatic ChIP-seq, ChIP-qPCR and ATAC-seq were used to analyze the histone modification properties and gene accessibility of STEAP3. Western blot and qRT-PCR were used to evaluate relative protein and gene expression, respectively. CRISPR/Cas9 technology was used to knockout STEAP3 on colon cancer cells to analyze the effect of ATF3 on STEAP3. STEAP3 was over-expressed in colon cancer and associated with higher metastases and more invasive and worse stage of colon cancer. ChIP-seq and ChIP-qPCR analyses revealed significant enrichment of H3K27ac in the STEAP3 gene. In addition, knocking down STEAP3 significantly inhibits colon cancer cell proliferation and migration and down-regulates H3K27ac expression. ChIP-seq found that ATF3 is enriched in the STEAP3 gene and CRISPR/Cas9 technology used for the deletion of the ATF3 binding site suppresses the expression of STEAP3. Over-expression of STEAP3 promotes colon cancer cell proliferation and migration. Mechanical studies have indicated that H3K27ac and ATF3 are significantly enriched in the STEAP3 gene and regulate the over-expression of STEAP3.

Nomogram for predicting the surgical difficulty of laparoscopic total mesorectal excision and exploring the technical advantages of robotic surgery.

Background: Total mesorectal excision (TME), represents a key technique in radical surgery for rectal cancer. This study aimed to construct a preoperative nomogram for predicting the surgical difficulty of laparoscopic total mesorectal excision (L-TME) and to investigate whether there were potential benefits of robotic TME (R-TME) for patients with technically challenging rectal cancer. Methods: Consecutive mid-low rectal cancer patients receiving total mesorectal excision were included. A preoperative nomogram to predict the surgical difficulty of L-TME was established and validated. Patients with technically challenging rectal cancer were screened by calculating the prediction score of the nomogram. Then patients with technically challenging rectal cancer who underwent different types of surgery, R-TME or L-TME, were analyzed for comparison. Results: A total of 533 consecutive patients with mid-low rectal cancer who underwent TME at a single tertiary medical center between January 2018 and January 2021 were retrospectively enrolled. Multivariable analysis demonstrated that mesorectal fat area, intertuberous distance, tumor size, and tumor height were independent risk factors for surgical difficulty. Subsequently, these variables were used to construct the nomogram model to predict the surgical difficulty of L-TME. The area under the receiver operating characteristic curve of the nomogram was 0.827 (95% CI 0.745 - 0.909) and 0.809 (95% CI 0.674- 0.944) in the training and validation cohort, respectively. For patients with technically challenging rectal cancer, R-TME was associated with a lower diverting ileostomy rate (p = 0.003), less estimated blood loss (p < 0.043), shorter procedure time (p = 0.009) and shorter postoperative hospital stay (p = 0.037). Conclusion: In this study, we established a preoperative nomogram to predict the surgical difficulty of L-TME. Furthermore, this study also indicated that R-TME has potential technical advantages for patients with technically challenging rectal cancer.

p53-dependent HIF-1α /autophagy mediated glycolysis to support Cr(VI)-induced cell growth and cell migration.

Cr(VI) is known to be seriously toxic and carcinogenic. Hypoxia-inducible factor-1α (HIF-1α) is a crucial regulator to promote tumor development. In this study, we found that Cr(VI) significantly increased the expression of HIF-1α in A549 cells and in lung of BALB/c mice but not in HELF cells. Treatment with Lificiguat (YC-1), HIF-1α inhibitor, or CoCl2, HIF-1α inducer, could alter Cr(VI)-induced autophagy, glycolysis, and cell growth in A549 cells but not in HELF cells, validating the involvement of HIF-1α in these effects of Cr(VI) in A549 cells. Co-treatments of pcATG4B with YC-1, or siATG4B with CoCl2 demonstrated the role of HIF-1α / autophagy axis in inducing glycolysis and cell growth in A549 cells. In HELF cells, however, only autophagy but not HIF-1α played a role in inducing glycolysis. The protein level of p53 was significantly lower in A549 cells than in HELF cells. RITA, a p53 inducer, attenuated Cr(VI)-induced HIF-1α and LC3-II in A549 cells, suggesting that p53 might be the mechanism underlying the different effects of Cr(VI) on HIF-1α in A549 and HELF cells. Thus, p53-dependent HIF-1α / autophagy-mediated glycolysis plays a role in facilitating Cr(VI)-induced carcinogenesis.

Modified aortic root anastomosis and the frozen elephant trunk technique using an integrated tetra-furcate graft to repair type A aortic dissection.

BACKGROUND: Surgery is the preferred treatment for acute Stanford type A aortic dissection (STAAD); however, due to the complexity of the procedure, cardiac ischaemia and cardiopulmonary bypass (CPB) time are longer than general heart surgery, leading to complications. In this present study, we used an integrated tetra-furcate graft for both modified aortic root and distal arch anastomoses (frozen elephant trunk technique, [FET]), and investigated postoperative outcomes associated with this technique in patients with STAAD. METHODS: We included a total of 140 patients who underwent total arch replacement and FET between January 2019 and June 2022 in the present study, 41 patients who underwent the modified technique, and 99 who underwent the graft eversion technique. We subsequently analyzed the perioperative outcomes to compare the differences between the two techniques. RESULTS: There were no statistically significant differences between the two groups in regards to the preoperative characteristics; however, the intraoperative CPB, cardiac ischaemia, and operation times of the modified technique group were significantly shorter than those of the eversion technique group (P = 0.02, P = 0.01, and P = 0.04, respectively), as were postoperative hypoxaemia, intensive care unit (ICU) stay, and ventilation times (P = 0.04, P = 0.03, and P = 0.04, respectively). Additionally, the degree of postoperative bilirubin elevation was milder in the modified technique group (P = 0.002 for direct bilirubin and P = 0.01 for indirect bilirubin). CONCLUSIONS: The modified anastomosis technique can significantly shorten CPB, cardiac ischemia, and operation times, and reduce the intraoperative FFP transfusion and postoperative hypoxemia times. This modified technique, therefore, is worth utilizing for patients with STAAD.

Nomogram for predicting prolonged postoperative ileus after laparoscopic low anterior resection for rectal cancer.

BACKGROUND: Prolonged postoperative ileus (PPOI) is a common complication after colorectal surgery that increases patient discomfort, hospital stay, and financial burden. However, predictive tools to assess the risk of PPOI in patients undergoing laparoscopic low anterior resection have not been developed. Thus, the purpose of this study was to develop a nomogram to predict PPOI after laparoscopic low anterior resection for rectal cancer. METHODS: A total of 548 consecutive patients who underwent laparoscopic low anterior resection for mid-low rectal cancer at a single tertiary medical center were retrospectively enrolled between January 2019 and January 2023. Univariate and multivariate logistic regression analysis was performed to analyze potential predictors of PPOI. The nomogram was constructed using the filtered variables and internally verified by bootstrap resampling. Model performance was evaluated by receiver operating characteristic curve and calibration curve, and the clinical usefulness was evaluated by the decision curve. RESULTS: Among 548 consecutive patients, 72 patients (13.1%) presented with PPOI. Multivariate logistic analysis showed that advantage age, hypoalbuminemia, high surgical difficulty, and postoperative use of opioid analgesic were independent prognostic factors for PPOI. These variables were used to construct the nomogram model to predict PPOI. Internal validation, conducted through bootstrap resampling, confirmed the great discrimination of the nomogram with an area under the curve of 0.738 (95%CI 0.736-0.741). CONCLUSIONS: We created a novel nomogram for predicting PPOI after laparoscopic low anterior resection. This nomogram can assist surgeons in identifying patients at a heightened risk of PPOI.

Augmenting interpretable models with large language models during training.

Recent large language models (LLMs), such as ChatGPT, have demonstrated remarkable prediction performance for a growing array of tasks. However, their proliferation into high-stakes domains and compute-limited settings has created a burgeoning need for interpretability and efficiency. We address this need by proposing Aug-imodels, a framework for leveraging the knowledge learned by LLMs to build extremely efficient and interpretable prediction models. Aug-imodels use LLMs during fitting but not during inference, allowing complete transparency and often a speed/memory improvement of greater than 1000x for inference compared to LLMs. We explore two instantiations of Aug-imodels in natural-language processing: Aug-Linear, which augments a linear model with decoupled embeddings from an LLM and Aug-Tree, which augments a decision tree with LLM feature expansions. Across a variety of text-classification datasets, both outperform their non-augmented, interpretable counterparts. Aug-Linear can even outperform much larger models, e.g. a 6-billion parameter GPT-J model, despite having 10,000x fewer parameters and being fully transparent. We further explore Aug-imodels in a natural-language fMRI study, where they generate interesting interpretations from scientific data.

Transcriptomic analysis revealing the molecular response to arsenic stress in desert Eremostachys moluccelloides Bunge.

The saline, alkaline environment of arid soils is conducive to the diffusion of the metalloid arsenic (As). Desert plants in this area are of great ecological importance and practical value. However, there are few studies on the mechanism of arsenic action in desert plants. Therefore, in this study, Eremostachys moluccelloides Bunge was treated with different concentrations of As2O5 [As(V)] to analyze the physiological, biochemical, and transcriptomic changes of its roots and leaves and to explore the molecular mechanism of its response to As(Ⅴ) stress. The activities of catalase, superoxidase, peroxidase, and the contents of malondialdehyde and proline in roots and leaves first increased and then decreased under the As(Ⅴ) stress of different concentrations. The content of As was higher in roots than in leaves, and the As content was positively correlated with As(Ⅴ) stress concentration. In the differentially expressed gene analysis, the key enzymes of the oxidative stress response in roots and leaves were significantly enriched in the GO classification. In the KEGG pathway, genes related to the abscisic acid signal transduction pathway were co-enriched and up-regulated in roots and leaves. The related genes in the phenylpropanoid biosynthesis pathway were significantly enriched and down-regulated only in roots. In addition, the transcription factors NAC, HB-HD-ZIP, and NF-Y were up-regulated in roots and leaves. These results suggest that the higher the As(V) stress concentration, the more As is taken up by roots and leaves of E. molucelloides Bunge. In addition to causing greater oxidative damage, this may interfere with the production of secondary metabolites. Moreover, it may improve As(V) tolerance by regulating abscisic acid and transcription factors. The results will deepen our understanding of the molecular mechanism of As(Ⅴ) response in E. moluccelloides Bunge, lay the foundation for developing and applying desert plants, and provide new ideas for the phytoremediation of As pollution in arid areas.

[Effect of electroacupuncture on proliferation and differentiation of endogenous neural stem cells and Jagged1/Notch1 pathway in hippocampus of APP/PS1 model mice].

OBJECTIVE: To investigate the effect of electroacupuncture(EA) stimulation on proliferation and diffe-rentiation of endogenous neural stem cells as well as Jagged1/Notch1 pathway in AD model mice, so as to explore its mechanism underlying amelioration of AD. METHODS: A total of 40 6-week-old male APP/PS1 transgenic AD mice were randomly divided into EA group (n=20) and AD model group ( n=20), and other 20 normal C57BL/6J mice of the same age were used as the normal control group. The mice in the EA group received EA (10 Hz, 2 mA) at "Baihui"(GV20), "Fengfu"(GV16) and bilateral "Shenshu" (BL23) for 20 min, once daily, 6 days a week for 16 weeks. The mice's learning-memory ability was detected by Morris water maze tests. The Aß senile plaques in the hippocampal CA1 region were detected by Congo red staining, the immunofluorescence double label of BrdU, neuronal nuclear antigen (NeuN) and astrocyte specific protein GFAP in dentate gyrus of hippocampus was performed for detecting the proliferation and differentiation of the endogenous neural stem cells. The expression levels of Nestin (neuron specific protein) and GFAP were detected by Western blot, and those of Jagged1 and Notch1 mRNAs and proteins in the hippocampus were detected by real-time fluorescence quantifative PCR and Western blot. RESULTS: Compared with the normal control group, the escape latencies at 2nd, 3rd and 4th day, and Aß senile plaques were significantly increased (P<0.05, P<0.01), whereas the platform crossing times and time spent in the target quadrant, the expression levels of Jagged1 mRNA and Nestin protein were remarkably down-regulated (P<0.05) in the model group. Following EA intervention, the escape latencies at the 3rd and 4th day, Aß senile plaques, immunofluorescence density of BrdU/GFAP, and GFAP protein expression were pronouncedly decreased (P<0.05, P<0.01), while the platform crossing times, platform quadrant residence time, immunofluorescence density of BrdU/NeuN, expression levels of Jagged1 and Notch1 mRNAs and proteins and Nestin protein evidently increased (P<0.05, P<0.01), suggesting an enhancement of proliferation and diffe-rentiation of endogenous neural stem cells into neurons and a suppression of the proliferation and differentiation towards astrocytes in the hippocampus. CONCLUSION: EA at GV20, GV16 and BL23 can improve the learning-memory ability, promote the proliferation and differentiation of endogenous neural stem cells towards neurons and inhibit the proliferation and differentiation of endogenous neural stem cells towards astrocytes in the hippocampus, which may be achieved by regulating Jagged1/Notch1 pathway.

Effect of minimally invasive versus conventional aortic root replacement on transfusion and postoperative wound complications in patients: A meta-analysis.

We examined whether small incision aortic root replacement could reduce the amount of blood transfusion during operation and the risk of postoperative complications. An extensive e-review of the 4 main databases (PubMed, Cochrane, Web of Science and EMBASE) was carried out to determine all the published trials by July 2023. The search terms used were associated with partial versus full sternotomy and aortic root. This analysis only included the study articles that compared partial and full sternotomy. After excluding articles based on titles or abstracts, selected full-text articles had reference lists searched for any potential further articles. We analysed a total of 2167 subjects from 10 comparable trials. The minimally invasive aortic root graft in breastbone decreased the duration of hospitalization (MD, -2.58; 95% CI, -3.15, -2.01, p < 0.0001) and intraoperative red blood cell transfusion (MD, -1.27; 95% CI, -2.34, -0.19, p = 0.02). However, there were no significant differences in wound infection (OR, 0.88; 95% CI, 0.16, 4.93, p = 0.88), re-exploration for bleeding (OR, 0.96; 95% CI, 0.60, 1.53, p = 0.86), intraoperative blood loss (MD, -259.19; 95% CI, -615.11, 96.73, p = 0.15) and operative time (MD, -7.39; 95% CI, -19.10, 4.32, p = 0.22); the results showed that the microsternotomy did not differ significantly from that of the routine approach. Small sternotomy may be an effective and safe substitute for the treatment of the aorta root. Nevertheless, the wide variety of data indicates that larger, well-designed studies are required to back up the current limited literature evidence showing a benefit in terms of complications like postoperative wound infections or the volume of intraoperative red blood cell transfusion.

Enhanced Mechanical Properties of PVA Hydrogel by Low-Temperature Segment Self-Assembly vs. Freeze-Thaw Cycles.

The rapid and effective fabrication of polyvinyl alcohol (PVA) hydrogels with good mechanical properties is of great significance yet remains a huge challenge. The preparation of PVA hydrogels via the conventional cyclic freeze-thaw method is intricate and time-intensive. In this study, a pioneering approach involving the utilization of low-temperature continuous freezing is introduced to produce a novel PVA-ethylene glycol (EG) gel. Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM) confirm that with the assistance of EG, PVA molecular chains can self-assemble to generate an abundance of microcrystalline domains at low temperatures, thus improving the mechanical properties of PVA-EG gel. Remarkably, when the mass ratio of H2O/EG is 4:6, the gel's maximum tensile strength can reach 2.5 MPa, which is much higher than that of PVA gels prepared via the freeze-thaw method. The preparation process of PVA-EG gel is simple, and its properties are excellent, which will promote the wide application of PVA tough gel in many fields.

Case report: Surgery combined with extracorporeal membrane oxygenation for a patient with type A aortic dissection complicated with myocardial infarction after percutaneous coronary intervention.

Background: Aortic dissection (AD) is a severe cardiovascular disease characterized by aortic rupture, aortic valve insufficiency, aortic branch lumen stenosis, and occlusion. Acute ST-segment elevation myocardial infarction may be the primary manifestation when aortic dissection affects the coronary artery, leading to delayed or missed diagnosis of aortic dissection, and preventing patients from receiving timely and comprehensive treatment. Simultaneous aortic repair and coronary artery bypass grafting surgery are controversial because of their high mortality rates. Personalized and optimal treatment plans for patients should be taken seriously based on their different conditions and treatment options. Case presentation: A 42-year-old man who experienced 1 h of persistent precordialgia was admitted to a local second-level hospital for emergency treatment. Electrocardiogram (ECG) showed evidence of ST-segment elevation, and myocardial enzyme levels were CK-MB 18.35 ng/ml and troponin 0.42 ng/ml. The patient was treated for acute myocardial infarction (AMI) and urgently sent to the interventional catheter room. Coronary angiography showed stenosis of the starting part of the right coronary artery trunk. Thus, stent implantation was performed, and the stenosis section recovered patency; however, postoperative precordialgia was not alleviated. Computed tomography angiography (CTA) revealed a type A AD. The patient was immediately transferred to a higher-level hospital, underwent emergency surgery with cardiopulmonary bypass (CPB) ascending aorta replacement, SUN's procedure (total arch replacement and stented elephant trunk implantation), and simultaneous implantation of extracorporeal membrane oxygenation (ECMO), and regained consciousness within intensive care unit care. ECMO was discontinued when hemodynamics stabilized. The patient ultimately recovered well and was discharged. Conclusion: This case demonstrated that precordialgia is not limited to myocardial infarction but may also be accompanied by aortic dissection. Percutaneous coronary intervention (PCI) can timely and effectively restore coronary artery perfusion, strive for the opportunity of aortic repair surgery, and can overcome pump failure caused by myocardial infarction, cardiopulmonary bypass, heart block time, and myocardial ischemia-reperfusion injury. Personalized treatment is crucial for patients with complex type A aortic dissection.

Study of Selective Dry Etching Effects of 15-Cycle Si0.7Ge0.3/Si Multilayer Structure in Gate-All-Around Transistor Process.

Gate-all-around (GAA) structures are important for future logic devices and 3D-DRAM. Inner-spacer cavity etching and channel release both require selective etching of Si0.7Ge0.3. Increasing the number of channel-stacking layers is an effective way to improve device current-driving capability and storage density. Previous work investigated ICP selective etching of a three-cycle Si0.7Ge0.3/Si multilayer structure and the related etching effects. This study focuses on the dry etching of a 15-cycle Si0.7Ge0.3/Si multilayer structure and the associated etching effects, using simulation and experimentation. The simulation predicts the random effect of lateral etching depth and the asymmetric effect of silicon nanosheet damage on the edge, both of which are verified by experiments. Furthermore, the study experimentally investigates the influence and mechanism of pressure, power, and other parameters on the etching results. Research on these etching effects and mechanisms will provide important points of reference for the dry selective etching of Si0.7Ge0.3 in GAA structures.

Influence of a Multiple Epoxy Chain Extender on the Rheological Behavior, Crystallization, and Mechanical Properties of Polyglycolic Acid.

This study investigated the impact of a multiple epoxy chain extender (ADR) on the rheological behavior, crystallization, and mechanical properties of polyglycolic acid (PGA). Tests of the torque and melt mass flow rate and dynamic rheological analysis were conducted to study the rheological behavior of PGA modified with ADR. The rheological results of the modified PGA showed a significantly increased viscosity and storage modulus with an increase in the ADR amount, which could be attributed to the chain extension/branching reactions between PGA and ADR. It was proved that ADR could be used as an efficient chain extender for tailoring the rheological performance of PGA. The Han plot of the modified PGA showed a transition of viscous behavior to elastic behavior, while the ADR content was increased from 0 to 0.9 phr. The formation of long-chain branches (LCBs) was confirmed via the Cole-Cole plot and weighted relaxation spectrum, wherein the LCBs substantially changed the rheological behavior of the modified PGA. The vGP plots predicted a star-type topological structure for the LCBs. The results of non-isothermal crystallization kinetics suggested that the crystallization of the modified PGA was predominantly homogeneous nucleation and three-dimensional growth. The crystallinity decreased slightly with the increase in the ADR amount. Compared to neat PGA, the modified PGA samples exhibited better tensile and flexural performances.

Radiofrequency ablation-induced superior vena cava stenosis in a 5-year-old boy with congenital left atrial appendage deformity: a case report and literature review.

Superior vena cava (SVC) stenosis is rarely caused by iatrogenic trauma. Herein, the case of a 5-year-old boy who underwent radiofrequency ablation for paroxysmal supraventricular tachycardia but developed SVC stenosis and related syndromes is reported. Notably, the child exhibited an enlarged left atrial appendage that had partially breached the pericardium. Subsequent interventions involved successful removal of the stenosis, artificial vascular reconstruction, and comprehensive radiofrequency ablation of the entire right atrium, along with ligation of the left atrial appendage under direct vision. As a result, the child experienced relief from symptoms.