Exploring the Adaptability of 4D Printed Shape Memory Polymer Featuring Dynamic Covalent Bonds.

4D printing (4DP) of high-performance shape memory polymers (SMPs), particularly using digital light processing (DLP), has garnered intense global attention due to its capability for rapid and high-precision fabrication of complex configurations, meeting diverse application requirements. However, the development of high-performance dynamic shape memory polymers (DSMPs) for DLP printing remains a significant challenge due to the inherent incompatibilities between the photopolymerization process and the curing/polymerization of high-strength polymers. Here, a mechanically robust DSMP compatible is developed with DLP printing, which incorporates dynamic covalent bonds of imine linking polyimide rigid segments, exhibiting remarkable mechanical performance (tensile strength ≈41.7 MPa, modulus ≈1.63 GPa) and thermal stability (Tg ∼ 113 °C, Td ∼ 208 °C). More importantly, benefiting from the solid-state plasticity conferred by dynamic covalent bonds, 4D printed structures demonstrate rapid network adaptiveness, enabling effortless realization of reconfiguration, self-healing, and recycling. Meanwhile, the extensive π-π conjugated structures bestow DSMP with an intrinsic photothermal effect, allowing controllable morphing of the 4D configuration through dual-mode triggering. This work not only greatly enriches the application scope of high-performance personalized configurations but also provides a reliable approach to addressing environmental pollution and energy crises.

Solvent Content Controlling Strategy for Cocrystallizable Polyesters Enables a Stress-Free Two-Way Shape Memory Effect with Wider Service Temperatures.

It is challenging to enhance the stress-free two-way shape memory (stress-free TWSM) effect to obtain a wide range of response temperatures. Herein, a polycaprolactone (PCL)/poly(ω-pentadecalactone) (PPDL) is photocured under UV light irradiation in the solvent of 1,1,2-trichloroethane (TCA), to obtain a series of cross-linked polyesters (CPES). Controlling solvent content (SC) which is removed after the polymerization allows the yielded CPES to perform a regulatable thermodynamic and stress-free TWSM properties. High SC is beneficial to reduce the degree of chain overlap (C/C* ) of PPDL chain segments in the PCL-based CPES network, then causes the cocrystallization of PCL and PPDL and yielding an additional melting-transitions (Tm ). An enhanced stress-free TWSM is obtained in high SC samples (CPES-15-90), reflected in the attainment of a wide range of response temperature, which means a wider service temperature. The enhancement is reflected in higher reversible strain of high SC samples compared with the samples prepared with low SC when varying high trigger temperature (Thigh ). Even at high Thigh , the high SC sample still has reversible strain. Therefore, controlling SC strategy for photocuring copolyester not only provides a new preparation approach for high-performance shape memory (SM) polymers, but also offers new condensed polymer structure to explore.

Strengthening-Durable Trade-Off and Self-Healing, Recyclable Shape Memory Polyurethanes Enabled by Dynamic Boron-Urethane Bonds.

Addressing the demand for integrating strength and durability reinforcement in shape memory polyurethane (SMPU) for diverse applications remains a significant challenge. Here a series of SMPUs with ultra-high strength, self-healing and recyclability, and excellent shape memory properties through introducing dynamic boron-urethane bonds are synthesized. The introducing of boric acid (BA) to polyurethane leading to the formation of dynamic covalent bonds (DCB) boron-urethane, that confer a robust cross-linking structure on the SMPUs led to the formation of ordered stable hydrogen-bonding network within the SMPUs. The flexible crosslinking with DCB represents a novel strategy for balancing the trade-off between strength and durability, with their strengths reaching up to 82.2 MPa while also addressing the issue of durability in prolonged usage through the provision of self-healing and recyclability. The self-healing and recyclability of SMPU are demonstrated through rapid dynamic exchange reaction of boron-urethane bonds, systematically investigated by dynamic mechanical analysis (DMA). This study sheds light on the essential role of such PU with self-healing and recyclability, contributing to the extension of the PU's service life. The findings of this work provide a general strategy for overcoming traditional trade-offs in preparing SMPUs with both high strength and good durability.

A Biocompatible 4D Printing Shape Memory Polymer as Emerging Strategy for Fabrication of Deployable Medical Devices.

The rapid development of 4D printing provides a potential strategy for the fabrication of deployable medical devices (DMD). The minimally invasive surgery to implant the DMD into the body is critical, 4D printing DMD allows the well-defined device to be implanted with a high-compacted shape and transformed into their designed shape to meet the requirement. Herein, a 4D printing tissue engineering material is developed with excellent biocompatibility and shape memory effect based on the photocrosslinked polycaprolactone (PCL). The fast thiol-acrylate click reaction is applied for photocrosslinking of the acrylates capped star polymer (s-PCL-MA) with poly-thiols, that enable the 3D printing for the DMD fabrication. The cell viability, erythrocyte hemolysis, and platelet adhesion results indicate the excellent biocompatibility of the 4D printing polymer, especially the biological subcutaneous implantation results confirm the promote tissue growth and good histocompatibility. A 4D printing stent with deformable shape and recovery at a temperature close to human body temperature demonstrated the potential application as DMD. In addition, the everolimus is loaded to the polymer (ps1-PCL) through host-guest coordination with ß-cyclodextrin as the core of the star polymer, which shows sustained drug release and improved body's inflammatory response.

Double common bile duct with cholelithiasis.

Double common bile duct is a rare congenital anomaly among biliary anomalies. The anomaly has an important clinical implication because of its association with biliary tract obstruction. In addition, if one of the two common bile ducts is mistaken for the cystic duct during surgery, residual stones and bile duct injury are likely to occur. Here, we report a case of double choledochal variation (Type Vb) with choledochal calculi. An 82-year-old woman was admitted to the hospital due to mild pain in the upper abdomen accompanied by vomiting for 3 days. Magnetic resonance imaging suggested common bile duct lithiasis, variation of the common bile duct and moderate biliary tract dilation. Laparoscopy combined with choledochoscopic lithotomy was performed for choledocholithotomy. During the operation, left and right choledocholithotomy was performed, and all the gallstones were removed via choledochoscope. The patient's post-operative recovery was good, and no recurrence of cholelith had been observed at the time of writing.

4D Printing of Shape Memory Vascular Stent Based on ßCD-g-Polycaprolactone.

The 4D-printing technology is applied to fabricate a shape memory peripheral stent with good biocompatibility, which sustains long-term drug release. The star polymer s-PCL is prepared by ring opening polymerization of ε-caprolactone with the -OH of ß-cyclodextrin (ßCD) as initiator, and then the s-PCL is modified with acrylate endgroup which allows the polymerization under UV light to form the crosslinking network c-PCL. Attributed to the feature of the high crosslinked structure and chemical nature of polycaprolactone (PCL) and ßCD, the composite exhibits appropriate tensile strength and sufficient elasticity and bursting pressure, and it is comparable with great saphenous vein in human body. The radial support of the 4D-printed stent is 0.56 ± 0.11 N and is equivalent to that of commercial stent. The cell adhesion and proliferation results show a good biocompatibility of the stent with human umbilical vein endothelial cells. Due to the presence of ßCD, the wettability and biocompatibility of the materials are improved, and the sustained paclitaxel release based on the host-guest complexion shows the potential of the drug-loaded stent for long-term release. This study provides a new strategy to solve the urgent need of small-diameter scaffolds to treat critical limb ischemia.

Long-term survival and recurrence after curative resection for hepatocellular carcinoma in patients with chronic hepatitis C virus infection: a multicenter observational study from China.

BACKGROUND: Hepatocellular carcinoma (HCC) is a recognized sequalae of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. This study aimed to identify long-term survival and prognostic factors after curative resection for HCC among patients with chronic HCV infection. METHODS: From a Chinese multicenter database, the data of consecutive patients with HCV infection undergoing curative liver resection for initial HCC between 2006 and 2015 were retrospectively reviewed. Postoperative 30-day mortality and morbidity, long-term overall survival (OS) and recurrence-free survival (RFS) were evaluated. RESULTS: Among 382 HCC patients with HCV infection, 68 (18%) had concurrent HBV infection and 110 (29%) had portal hypertension. Postoperative 30-day morbidity and mortality rates were 45% and 2.9%, respectively. The 5-year OS and RFS rates were 45% and 34%, respectively. Multivariable Cox-regression analyses identified that concurrent HBV infection, presence of portal hypertension, largest tumor size > 5 cm, and macrovascular and microvascular invasion were independently associated with worse OS and RFS, while postoperative regular anti-HCV therapy was independently associated with better OS. CONCLUSION: Long-term prognosis after HCC resection among patients with HCV infection was worse in those with concurrent HBV infection and concomitant portal hypertension. Postoperative regular anti-HCV therapy was associated with better OS.

Multicenter analysis of long-term oncologic outcomes of hepatectomy for elderly patients with hepatocellular carcinoma.

BACKGROUND: Aging of the population and prolonged life expectancy have significantly increased the number of elderly patients undergoing hepatectomy for hepatocellular carcinoma (HCC). However, potential benefits, especially long-term oncologic outcomes of hepatectomy for elderly patients with HCC remain unclear. METHOD: Patients treated with curative-intent hepatectomy for HCC in 8 Chinese hospitals were enrolled. Patients were divided into the elderly (≥70 years old) and younger (<70 years old) groups. Overall survival (OS), cancer-specific survival (CSS), and time-to-recurrence (TTR) were compared. Risk factors of CSS and TTR were evaluated by univariable and multivariable competing-risk regression analyses. RESULTS: Of 2134 patients, 259 (12.1%) and 1875 (87.9%) were elderly and younger aged, respectively. Postoperative 30-day and 90-day mortality was comparable among elderly and younger patients. Compared with younger patients, the elderly had a worse 5-year OS (49.4% vs. 55.3%, P = 0.032), yet a better 5-year CCS (74.5% vs. 61.0%, P = 0.005) and a lower 5-year TTR (33.7% vs. 44.9%, P < 0.001), respectively. Multivariable analyses identified that elder age was independently associated with more favorable CSS (HR 0.74, 95%CI 0.58-0.90, P = 0.011) and TTR (0.69, 0.53-0.88, P < 0.001) but was not associated with OS (P = 0.136). CONCLUSIONS: Age by itself is not a contraindication to surgery, and selected elderly patients with HCC can benefit from hepatectomy. Compared with younger patients, elderly patients have noninferior oncologic outcomes following hepatectomy for HCC.

Impact of iatrogenic biliary injury during laparoscopic cholecystectomy on surgeon's mental distress: a nationwide survey from China.

BACKGROUND: Iatrogenic biliary injury (IBI) following laparoscopic cholecystectomy (LC) is the most serious iatrogenic complications. Little is known whether LC-IBI would lead to surgeon's severe mental distress (SMD). METHODS: A cross-sectional survey in the form of electronic questionnaire was conducted among Chinese general surgeons who have caused LC-IBI. The six collected clinical features relating to mental distress included: 1) feeling burnout, anxiety, or depression, 2) avoiding performing LC, 3) having physical reactions when recalling the incidence, 4) having the urge to quit surgery, 5) taking psychiatric medications, and 6) seeking professional psychological counseling. Univariable and multivariable analyses were performed to identify risk factors of SMD, which was defined as meeting ≥3 of the above-mentioned clinical features. RESULTS: Among 1466 surveyed surgeons, 1236 (84.3%) experienced mental distress following LC-IBI, and nearly half (49.7%, 614/1236) had SMD. Multivariable analyses demonstrated that surgeons from non-university affiliated hospitals (OR:1.873), patients who required multiple repair operations (OR:4.075), patients who required hepaticojejunostomy/partial hepatectomy (OR:1.859), existing lawsuit litigation (OR:10.491), existing violent doctor-patient conflicts (OR:4.995), needing surgeons' personal compensation (OR:2.531), and additional administrative punishment by hospitals (OR:2.324) were independent risk factors of surgeon's SMD. CONCLUSION: Four out of five surgeons experienced mental distress following LC-IBI, and nearly half had SMD. Several independent risk factors of SMD were identified, which could help to make strategies to improve surgeons' mental well-being.

Direct Observation of Dynamic Bond Evolution in Single-Atom Pt/C3 N4 Catalysts.

Single-atom catalysts are promising platforms for heterogeneous catalysis, especially for clean energy conversion, storage, and utilization. Although great efforts have been made to examine the bonding and oxidation state of single-atom catalysts before and/or after catalytic reactions, when information about dynamic evolution is not sufficient, the underlying mechanisms are often overlooked. Herein, we report the direct observation of the charge transfer and bond evolution of a single-atom Pt/C3 N4 catalyst in photocatalytic water splitting by synchronous illumination X-ray photoelectron spectroscopy. Specifically, under light excitation, we observed Pt-N bond cleavage to form a Pt0 species and the corresponding C=N bond reconstruction; these features could not be detected on the metallic platinum-decorated C3 N4 catalyst. As expected, H2 production activity (14.7 mmol h-1 g-1 ) was enhanced significantly with the single-atom Pt/C3 N4 catalyst as compared to metallic Pt-C3 N4 (0.74 mmol h-1 g-1 ).

Long-Term Survival Outcomes After Liver Resection for Binodular Hepatocellular Carcinoma: A Multicenter Cohort Study.

BACKGROUND: The long-term prognosis after liver resection for multinodular (≥3 nodules) hepatocellular carcinoma (HCC) is generally considered to be unfavorable. However, the role of liver resection for binodular HCC is less investigated. SUBJECTS, MATERIALS, AND METHODS: From a multicenter database, consecutive patients who underwent curative-intent liver resection for binodular HCC and without macrovascular invasion between 2003 and 2015 were retrospectively reviewed. Patients' clinical variables as well as perioperative and long-term survival outcomes were analyzed. Univariable and multivariable analyses were performed to identify the risk factors associated with overall survival (OS) and recurrence-free survival (RFS) after curative resection. RESULTS: Of 263 enrolled patients, the perioperative 30-day mortality and morbidity rates were 1.5% and 28.5%. The 1-, 3-, and 5-year OS and RFS rates were 81.5%, 52.4%, and 39.1% and 57.1%, 35.8%, and 26.6%, respectively. Multivariable Cox-regression analyses identified preoperative alpha-fetoprotein level >400 µg/L, tumor size with a sum of two nodules >8 cm, tumor size ratio of large/small nodule >1.5 (asymmetrical proportion), unilateral hemiliver distribution of two nodules, distance of ≤3 cm between two nodules, and microvascular invasion in any nodule as independent risk factors associated with decreased OS and RFS. CONCLUSION: Liver resection was safe and feasible in patients with binodular HCC, with acceptable perioperative and long-term outcomes. Sum of two tumor sizes, size ratio and distribution, and distance between two nodules were independent risk factors associated with long-term survival outcomes after surgery. These results may guide clinicians to make individualized surgical decisions and estimate long-term prognosis for these patients. IMPLICATIONS FOR PRACTICE: Liver resection was safe and feasible in patients with binodular hepatocellular carcinoma, with acceptable perioperative and long-term outcomes. The sum of two tumor sizes, the size ratio and distribution of the two nodules, and the distance between two nodules were independent risk factors associated with long-term overall survival and recurrence-free survival after liver resection. The results of this study may guide clinicians to make individualized surgical decisions, estimate long-term prognosis, and plan recurrence surveillance and adjuvant therapy for these patients.

Evolution of Morphology of POEGMA-b-PBzMA Nano-Objects Formed by PISA.

The evolution of particle morphology occurring during polymerization-induced self-assembly (PISA) of a block copolymer poly(oligo(ethylene glycol) methacrylate)-b-poly(benzyl methacrylate) (POEGMA-b-PBzMA) is studied. A well-controlled reversible addition-fragmentation chain transfer (RAFT) polymerization yields nano-objects with various morphologies: spheres, aggregates, worm-like structures, and vesicles. A comparison of the morphology of the nano-objects formed from two different chain-length stabilizers established that the unreacted monomer played an important role during the morphology transitions, which is contrary to previous observations. In addition, morphology evolution to higher-order structures could be attained simply by extending the reaction time, after reaching full monomer conversion.

Targeting FBPase is an emerging novel approach for cancer therapy.

Cancer is a leading cause of death in both developed and developing countries. Metabolic reprogramming is an emerging hallmark of cancer. Glucose homeostasis is reciprocally controlled by the catabolic glycolysis and anabolic gluconeogenesis pathways. Previous studies have mainly focused on catabolic glycolysis, but recently, FBPase, a rate-limiting enzyme in gluconeogenesis, was found to play critical roles in tumour initiation and progression in several cancer types. Here, we review recent ideas and discoveries that illustrate the clinical significance of FBPase expression in various cancers, the mechanism through which FBPase influences cancer, and the mechanism of FBPase silencing. Furthermore, we summarize some of the drugs targeting FBPase and discuss their potential use in clinical applications and the problems that remain unsolved.

Reversibly Cross-Linkable Thermoresponsive Self-Folding Hydrogel Films.

This paper reports a novel approach for the design of self-folding films using reversibly cross-linkable thermoresponsive polymers with coumarin groups: poly(N-isopropylacrylamide-co-7-(2-methacryloyloxyethoxy)-4-methylcoumarin). We demonstrated that, depending on the structure of the films and the conditions of cross-linking/de-cross-linking, one can fabricate a variety of different forms ranging from simple tubes to complex centipede-like structures. The demonstrated approach opens new perspectives for the design of 3D self-assembling materials.