Sandwich-Like Flexible Breathable Strain Sensor with Tunable Thermal Regulation Capability for Human Motion Monitoring.

High-performance flexible strain sensors with synergistic and outstanding thermal regulation function are poised to make a significant impact on next-generation multifunctional sensors. However, it has long been intractable to optimize the sensing performance and high thermal conductivity simultaneously. Herein, a novel flexible sandwich-like strain sensor with advanced thermal regulation capability was prepared by assembling electrospun thermoplastic polyurethane (TPU) fibrous membrane, MXene layer, and TPU/boron nitride nanosheet (BNNS) composite films. The as-prepared sensor demonstrates a wide strain working range (∼100% strain), an ultrahigh gauge factor (2080.9), and a satisfactory reliability. Meanwhile, benefiting from the uniform dispersion and promising orientation of BNNSs in TPU composites, the sensor possesses a high thermal conductivity of 1.5 W·m-1·K-1, guaranteeing wearer comfort. Additionally, the unique structure endows the sensor with high stretchability, breathability, biocompatibility, and tunable electromagnetic interference shielding performances. Furthermore, an integrated wireless motion monitoring device based on this sensor is rationally designed. It exhibits a fast response time, a wide recognition range, and the ability to maintain skin temperature during prolonged physical activity. These encouraging findings provide a new and feasible approach to designing high-performance and versatile flexible strain sensors with broad applications in advanced wearable technology.

High Value-Added Reutilization of Waste-Printed Circuit Boards Non-Metallic Components in Sustainable Polymer Composites.

The reutilization non-metallic components from a waste-printed circuit board (WPCB) has become one of the most significant bottlenecks in the comprehensive reuse of electronic wastes due to its low value and complex compositions, and it has received great attention from scientific and industrial researchers. To effectively address the environmental pollution caused by inappropriate recycling methods, such as incineration and landfill, extensive efforts have been dedicated to achieving the high value-added reutilization of WPCB non-metals in sustainable polymer composites. In this review, recent progress in developing sustainable polymer composites based on WPCB non-metallic components was systematically summarized. It has been demonstrated that the WPCB non-metals can serve as a promising reinforcing and functional fillers to significantly ameliorate some of the physical and chemical properties of polymer composites, such as excellent mechanical properties, enhanced thermal stability, and flame retardancy. The recovery strategies and composition of WPCB non-metals were also briefly discussed. Finally, the future potentials and remaining challenges regarding the reutilization of WPCB non-metallic components are outlined. This work provides readers with a comprehensive understanding of the preparation, structure, and properties of the polymer composites based on WPCB non-metals, providing significant insights regarding the high value-added reutilization of WPCB non-metals of electronic wastes.

Phase Change Composite Microcapsules with Low-Dimensional Thermally Conductive Nanofillers: Preparation, Performance, and Applications.

Phase change materials (PCMs) have been extensively utilized in latent thermal energy storage (TES) and thermal management systems to bridge the gap between thermal energy supply and demand in time and space, which have received unprecedented attention in the past few years. To effectively address the undesirable inherent defects of pristine PCMs such as leakage, low thermal conductivity, supercooling, and corrosion, enormous efforts have been dedicated to developing various advanced microencapsulated PCMs (MEPCMs). In particular, the low-dimensional thermally conductive nanofillers with tailorable properties promise numerous opportunities for the preparation of high-performance MEPCMs. In this review, recent advances in this field are systematically summarized to deliver the readers a comprehensive understanding of the significant influence of low-dimensional nanofillers on the properties of various MEPCMs and thus provide meaningful enlightenment for the rational design and multifunction of advanced MEPCMs. The composition and preparation strategies of MEPCMs as well as their thermal management applications are also discussed. Finally, the future perspectives and challenges of low-dimensional thermally conductive nanofillers for constructing high performance MEPCMs are outlined.

Emergency decompression for patients with ureteral stones and SIRS: a prospective randomized clinical study.

OBJECTIVE: Patients with ureteral calculi and systemic inflammatory response syndrome (SIRS) often require emergency drainage, and percutaneous nephrostomy (PCN) and retrograde ureteral stent insertion (RUSI) are the most commonly used methods. Our study aimed to identify the best choice (PCN or RUSI) for these patients and to examine the risk factors for progression to urosepsis after decompression. METHODS: A prospective, randomized clinical study was performed at our hospital from March 2017 to March 2022. Patients with ureteral stones and SIRS were enrolled and randomized to the PCN or RUSI group. Demographic information, clinical features and examination results were collected. RESULTS: Patients (n = 150) with ureteral stones and SIRS were enrolled into our study, with 78 (52%) patients in the PCN group and 72 (48%) patients in the RUSI group. Demographic information was not significantly different between the groups. The final treatment of calculi was significantly different between the two groups (p < .001). After emergency decompression, urosepsis developed in 28 patients. Patients with urosepsis had a higher procalcitonin (p = .012) and blood culture positivity rate (p < .001) and more pyogenic fluids during primary drainage (p < .001) than patients without urosepsis. CONCLUSION: PCN and RUSI were effective methods of emergency decompression in patients with ureteral stone and SIRS. Patients with pyonephrosis and a higher PCT should be carefully treated to prevent the progression to urosepsis after decompression.Key messageIn this study, we evaluate the best choice (PCN or RUSI) for patients who have ureteral stones and SIRS and to examine the risk factors for progression to urosepsis after decompression. This study found that PCN and RUSI were effective methods of emergency decompression. Pyonephrosis and higher PCT were risk factors for patients to develop to urosepsis after decompression.

Mini-PCNL with a vacuum-assisted access sheath for renal calculi with pyonephrosis in the second stage.

OBJECTIVE: To compare the safety and efficacy of mini-PCNL with vacuum-assisted access sheath in the second-stage treatment of renal calculi with obstructive pyonephrosis. MATERIAL AND METHODS: A prospective, randomized clinical study was performed at our hospital from May 2020 to May 2022. Patients with pyogenic drainage fluid who needed percutaneous nephrolithotomy were randomized to the peel-away assisted mini-PCNL group (group A) and the vacuum-assisted mini-PCNL group (group B). Demographic information, clinical features, and perioperative period data were collected. RESULTS: Fifty mini-PCNLs using a single 16 F access sheath were performed in all patients of our study. All patients underwent second-stage surgical treatment. Demographic information and clinical features were not significantly different between groups A and B. But compared with group A, patients in group B had a short operative time (60.60 ± 7.68 min vs. 82.20 ± 14 min p = 0.018), a lower post-operative fever rate (8% vs. 32% p = 0.034), and a higher stone-free rate 2 d after the operation (88% vs. 64% p = 0.047). There was no significant difference between the two groups in blood transfusion, HB deficit, PCT after the operation, total hospitalization costs, stone-free rate 30 d after the operation, and length of stay or stay post-operative. And no serious complications after the operation occurred in either group. CONCLUSIONS: Mini-PCNL with vacuum-assisted access sheath is a safe and efficient treatment for patients with calculi-related obstructive pyonephrosis in the second stage.

High attenuation value in non-contrast computer tomography can predict pyonephrosis in patients with upper urinary tract stones.

To evaluate whether the higher attenuation value [Hounsfield unit (HU)] in non-contrast CT can predict pyonephrosis in patients with upper urinary tract stones (UTS). Between October 2019 and October 2021, patients with hydronephrosis or pyonephrosis secondary to upper UTS were retrospectively searched in our study. All patients with UTS were treated with percutaneous nephrostomy, percutaneous nephrolithotomy, retrograde ureteral stent or transurethral ureteroscope lithotripsy. We excluded patients treated with extracorporeal shock-wave lithotripsy. Patients whose CT was not performed in our hospital or treated in another hospital were also excluded. Clinical data regarding basic information, clinical feature, Calculi-related indicators, HU values of the renal pelvis, the thick wall of the renal pelvis on CT were collected. Univariate and multivariate logistic analyses were performed. Receiver operative characteristic curves were drawn to predict pyonephrosis. A total of 240 patients with UTS were retrospected in this research, 191 patients had hydronephrosis (Group 1), and 49 patients had hydronephrosis with pyonephrosis (Group 2). The HU value of the renal collecting system in Group 2 (mean, 15.46; range, +1/+30) was significantly higher than that in Group 1 (mean, 5.5; 5 range -6/+24) (P = .02); the receiver operative characteristic curve analysis revealed that the best cut-off value of 9.5 could predict the presence of pyonephrosis, with 71.4% sensitivity and 70.2% specificity (area under the curve = 0.613; 95% CI: 0.514-0.713). In this study, we found the HU attenuation value of the renal collecting system can be used to distinguish pyonephrosis from hydronephrosis in patients with UTS.

Synergetic integration of thermal conductivity and flame resistance in nacre-like nanocellulose composites.

Highly thermally conductive and flame resistant nanocellulose-based composites can synchronously achieve efficient thermal dissipation and low fire hazards of electronic devices, which shows great promise in next-generation green and flexible electronics. However, it has long been intractable to optimize the high thermal conductivity (TC) and flame resistance simultaneously. Herein, synergetic integration of high TC and flame resistance in nacre-like nanocellulose composites has been successfully achieved by the vacuum-assisted filtration of cellulose nanofibers (CNFs) and functionalized boron nitride nanosheets (BNNS-p-APP). Benefiting from the highly oriented hierarchical microstructure, strong hydrogen-bonding interaction, and successful immobilization of ammonium polyphosphate (APP), the as-obtained CNFs/BNNS-p-APP composite film achieves a high in-plane TC of 9.1 W m-1 K-1 and outstanding flame resistance. Meantime, this eco-friendly nanocellulose-based composite also exhibits remarkable flexibility, folding endurance, and mechanical robustness, robustness, which may open up a new opportunity for the thermal management of flexible electronics.

Dual Bio-Inspired Design of Highly Thermally Conductive and Superhydrophobic Nanocellulose Composite Films.

Highly thermally conductive, electrically insulating, and flexible nanocellulose composite films are crucially significant for the thermal management of next-generation green electronics. However, the intrinsic hygroscopicity of nanocellulose poses a daunting challenge to the reliability and structural stability of electronic products. To address these issues, herein, a dual bio-inspired design was innovatively introduced to fabricate highly thermally conductive and superhydrophobic nanocellulose-based composite films via vacuum-assisted self-assembly of cellulose nanofibers (CNFs) and hydroxylated boron nitride nanosheets (OH-BNNS) and subsequent hydrophobic modification. Driven by the highly orderly hierarchical architecture and a strong hydrogen bonding interaction, the laminated CNF-based composite films with 50 wt % OH-BNNS show a high in-plane thermal conductivity (15.13 W/mK), which results in a 505% enhancement compared with the pure CNF films. On the other hand, the rough surface combined with a low surface energy modifier endows CNF/OH-BNNS composite films with unique superhydrophobicity (contact angle over 155°) and a simultaneous self-cleaning function. Furthermore, the as-fabricated multifunctional CNF/OH-BNNS composite films were designed as a flexible printed circuit board to simulate the potential applications in the field of cooling electronic devices. The development of CNF/OH-BNNS composite films with synergetic properties of high thermal conductivity and superhydrophobicity may shed light on the functional thermal management materials and offer an innovative insight toward fabricating multifunctional nanocomposites via a dual bio-inspired design.

Functionalized Halloysite Nanotubes⁻Silica Hybrid for Enhanced Curing and Mechanical Properties of Elastomers.

Vulcanization and reinforcement are critical factors in governing the ultimate practical applications of elastomer composites. Here we achieved a simultaneous improvement of curing and mechanical properties of elastomer composites by the incorporation of a functionalized halloysite nanotubes-silica hybrid (HS-s-M). Typically, HS-s-M was synthesized by 2-mercapto benzothiazole (M) immobilized on the surface of halloysite nanotubes-silica hybrid (HS). It was found that the HS-s-M uniformly dispersed in the styrene-butadiene rubber (SBR) matrix, offering more opportunity for M molecules to communicate with rubber. In addition, the physical loss of accelerator M from migration and volatilization was efficiently suspended. Therefore, SBR/HS-s-M composites showed a lower curing activation energy and a higher crosslinking density than SBR/HS composites. Moreover, a stronger interfacial interaction between HS-s-M and SBR was formed by the cross-linking reaction, giving a positive contribution to the eventual mechanical properties. The possible vulcanization and reinforcement mechanisms of SBR/HS-s-M composites were also analyzed in detail.

Immobilization of rubber additive on graphene for high-performance rubber composites.

It is still a challenge to achieve simultaneous improvements in aging resistance, mechanical strength, thermal conductivity and dielectric constant of rubber composites via incorporation of graphene obtained by conventional methods. Herein, an effective and green method was proposed to simultaneously reduce and functionalize graphene oxide (GO) with 2-mercaptobenzimidazole (antioxidant MB) via a one-pot method. GO was successfully reduced by MB which was also chemically grafted on the reduced GO (G-MB). G-MB sheets were uniformly dispersed in rubber with strong interfacial interaction, and graphene-graphene conductive paths were formed through intermolecular H-bonding between the grafted antioxidant molecules. Consequently, rubber composites with G-MB showed higher thermal conductivity, mechanical strength and dielectric constant than rubber composites with hydrazine hydrate reduced GO (rGO). Moreover, the thermo-oxidative aging resistance of rubber composites with G-MB was also superior to that of rubber composites with rGO because of the elimination of blooming effect of the grafted MB molecules. Thus, this work may open a new way for the eco-friendly functionalization and reduction of GO and may boost the development of high-performance, functional graphene-elastomer composites.