Thermal Gelation Research Articles

3D bioprinting of tissue constructs employing dual crosslinking of decellularized extracellular matrix hydrogel

Bioprinted tissues are currently being utilized for drug and cosmetic screening mostly, but the long-term goal is to achieve human scale functional tissues and organs for transplantation. Hence, recapitulating the multiscale architecture, 3D structures, and complexity of native tissues is the key to produce bioengineered tissues/organs. Decellularized extracellular matrix (dECM)-based biomaterials are widely being used as bioinks for 3D bioprinting for tissue engineering applications. Their potential to provide excellent biocompatibility for the cells drove researchers to use them extensively. However, the decellularization process involves many detergents and enzymes which may contribute to their loss of mechanical properties. Moreover, thermal gelation of dECM-based hydrogels is typically slow which affects the shape fidelity, printability, and physical properties while printing complex structures with 3D printing. But, thermally gelled dECM hydrogels provide excellent cell viability and functionality. To overcome this, a novel dual crosslinking of unmodified dECM has been proposed in this study to render shape fidelity and enhance cell viability and functionality. The dECM-based bioink can be initially polymerized superficially on exposure to light to achieve immediate stability and can attain further stability upon thermal gelation. This dual crosslinking mechanism can maintain the microenvironment of the structure, hence allowing the printing of stable flexible structures. Optimized concentrations of novel photo crosslinkers have been determined and printing of a few complex-shaped anatomical structures has been demonstrated. This approach of fabricating complex scaffolds employing dual crosslinking can be used for the bioprinting of different complex tissue structures with tissue-specific dECM based bioinks.

Building Fucoidan/Agarose-Based Hydrogels as a Platform for the Development of Therapeutic Approaches against Diabetes.

Current management for diabetes has stimulated the development of versatile 3D-based hydrogels as in vitro platforms for insulin release and as support for the encapsulation of pancreatic cells and islets of Langerhans. This work aimed to create agarose/fucoidan hydrogels to encapsulate pancreatic cells as a potential biomaterial for diabetes therapeutics. The hydrogels were produced by combining fucoidan (Fu) and agarose (Aga), marine polysaccharides derived from the cell wall of brown and red seaweeds, respectively, and a thermal gelation process. The agarose/fucoidan (AgaFu) blended hydrogels were obtained by dissolving Aga in 3 or 5 wt % Fu aqueous solutions to obtain different proportions (4:10; 5:10, and 7:10 wt). The rheological tests on hydrogels revealed a non-Newtonian and viscoelastic behavior, while the characterization confirmed the presence of the two polymers in the structure of the hydrogels. In addition, the mechanical behavior showed that increasing Aga concentrations resulted in hydrogels with higher Young's modulus. Further, the ability of the developed materials to sustain the viability of human pancreatic cells was assessed by encapsulation of the 1.1B4HP cell line for up to 7 days. The biological assessment of the hydrogels revealed that cultured pancreatic beta cells tended to self-organize and form pseudo-islets during the period studied.

3D printing of mechanically functional meniscal tissue equivalents using high concentration extracellular matrix inks

Decellularized extracellular matrix (dECM) has emerged as a promising biomaterial in the fields of tissue engineering and regenerative medicine due to its ability to provide specific biochemical and biophysical cues supportive of the regeneration of diverse tissue types. Such biomaterials have also been used to produce tissue-specific inks and bioinks for 3D printing applications. However, a major limitation associated with the use of such dECM materials is their poor mechanical properties, which limits their use in load-bearing applications such as meniscus regeneration. In this study, native porcine menisci were solubilized and decellularized using different methods to produce highly concentrated dECM inks of differing biochemical content and printability. All dECM inks displayed shear thinning and thixotropic properties, with increased viscosity and improved printability observed at higher pH levels, enabling the 3D printing of anatomically defined meniscal implants. With additional crosslinking of the dECM inks following thermal gelation at pH 11, it was possible to fabricate highly elastic meniscal tissue equivalents with compressive mechanical properties similar to the native tissue. These improved mechanical properties at higher pH correlated with the development of a denser network of smaller diameter collagen fibers. These constructs also displayed repeatable loading and unloading curves when subjected to long-term cyclic compression tests. Moreover, the printing of dECM inks at the appropriate pH promoted a preferential alignment of the collagen fibers. Altogether, these findings demonstrate the potential of 3D printing of highly concentrated meniscus dECM inks to produce mechanically functional and biocompatible implants for meniscal tissue regeneration. This approach could be applied to a wide variety of different biological tissues, enabling the 3D printing of tissue mimics with diverse applications from tissue engineering to surgical planning.

Chip Level Thermal Performance Measurements in Two-Phase Immersion Cooling

Abstract Two-phase immersion cooling (2PIC) has been proposed as a means of economically increasing overall energy efficiency while accommodating increased chip powers and system-level power density. Designers unfamiliar with Two-phase immersion technology may be unaware of the chip-level thermal performance capabilities of the technology. This performance, in the case of a lidded processor, is quantified as a case-to-fluid thermal resistance, Rcf. This work made use of boiler assemblies comprised of copper plates to which two porous metallic boiling enhancement coatings (BECs) had been applied. These boiler assemblies were applied with conventional thermal grease to a thermal test vehicle (TTV) emulating the Skylake series of 8th Gen Intel® Xeon® CPUs and a thermal test slug (TTS) emulating the Advanced Micro Devices, Inc. (AMD) EPYCTM processors. Both were tested in saturated 3MTM FluorinertTM FC-3284 fluid. The lowest Rcf = 0.020 °C/W was achieved on the TTS at 350 W. The paper also includes additional TTS data gathered with different boiler assemblies and Thermal Interface Materials as well as field data in the form of Rcf or junction-to-fluid thermal resistances, Rjf, for different live silicon chips.

Eggnog: process optimization and characterization of a dairy-based beverage.

Eggnog, a dairy-based beverage, comprises both milk and egg proteins. We aimed at optimizing the eggnog formulation using Box-Behnken design of response surface methodology. The combined effects of milk (60-75), cream (25-35) and eggnog base (6-8, all three as g 100/ml) were investigated on heat coagulation time, viscosity and thermal gelation temperature. ANOVA indicated that experimental data were well explained by a quadratic model with high check values (R2 > 0.94) and non-significant lack of fit tests. Based on the responses, an optimized formulation of eggnog with 60.0 milk, 25.0 cream and 6.50 eggnog base (as g 100/ml), could be considered best for manufacturing eggnog with desired attributes. This optimized formulation was characterized for physico-chemical, microbial and sensory attributes and the results indicated significantly higher fat and protein content than control formulation, but lesser lactose and total sugar content. Significantly higher viscosity, heat stability and lower thermal gelation temperature were also observed for the optimized formulation. Coliform, yeast and mold, E. coli and Salmonella counts were not detected in any sample but a significantly lower total plate count was observed for the optimized formulation.

Dose-Dependent Effect of Hyperoside on the Physicochemical and Gel Properties of Porcine Myofibrillar Proteins at Different NaCl Concentrations under Oxidative Stress.

The effects of HYP (10, 50, and 250 μM/g protein) on the physicochemical and gel properties of myofibrillar proteins (MPs) at different NaCl concentrations under oxidative stress were explored. The incorporation of HYP significantly reduced carbonyl content and decreased the loss of free amine groups in a dose-dependent manner, regardless of NaCl concentration. In addition, HYP induced a dose-dependent decrement in total sulfhydryl content regardless of NaCl concentration, which might result from the formation of thiol-quinone adducts via Michael addition. The surface hydrophobicity was significantly increased with HYP addition. Nevertheless, compared with samples treated with 50 μM/g HYP, 250 μM/g HYP caused a significant decrease in surface hydrophobicity, which might be due to the increase in the extent of MPs unfolding and the concomitant aggregation of MPs by hydrophobic interaction. Furthermore, HYP also showed a dose-dependent increment in the water-holding capacity (WHC) and gel strength of MPs gels, which might be due to more orderly crosslinks via fibrous filaments at 0.2 M NaCl and more regular and lamellar structures with smaller and more homogeneous pores at 0.6 M NaCl. In summary, HYP reduced the oxidation-mediated changes of physicochemical characteristics, preventing the oxidative damage of MPs and reinforcing the ordered crosslinks of MPs-MPs and MPs-HYP during thermal gelation, ultimately resulting in a better gel quality. These results provide a theoretical support for the practical application of HYP as a natural antioxidant in gel-type meat products.

Insight into transglutaminase cross‐linking induced gel strength and thermal stability improving of gelatin‐based emulsion‐filled gels

SummaryGenerally, gelatin‐based emulsion‐filled gels (EFGs) tend to liquefy and degradation under heat sterilisation. In this study, transglutaminase (TG) cross‐linking gelatin‐based EFGs with high thermal stability and gel strength were prepared. By analysing the rheological properties, thermal stability, structural changes and their underlying mechanisms, the impact of varying cross‐linking time on the thermal stability and gel strength of EFGs was explored. Results showed that enzymatic EFGs exhibited a higher gel strength with a high elastic modulus and low‐frequency dependence along with a prolonged TG cross‐linking time. The thermal denaturation temperature was increased by 21.87 °C after TG cross‐linking for 4 h compared to that of uncross‐linked EFGs. The surface of fully cross‐linked EFGs was smoother, and the surface voids were reduced. As the TG cross‐linking time increased, the inter‐molecular hydrogen bonds were weakened, the covalent bonds were strengthened and the triple helical structure was altered. After full cross‐linking, the original ordered structure of gelatin molecules was destroyed, the formation of crystalline structure was hindered and the interplanar crystal spacing was more tightly. This study provides a facile method for the preparation of gelatin‐based products with high thermal stability and proposes theoretical guidance for its practical application.

Impact of pin‐to‐plate cold plasma depolymerization on the gelation and functional attributes of guar galactomannan

AbstractThe present study aimed to investigate the impact of pin‐to‐plate cold plasma on the gelation and functional attributes of guar seed galactomannan. The guar galactomannan was subjected to 170 and 230 V treatment for 30 and 60 min and investigated for the gel characteristics and functional properties. The cold plasma treatment incurred galactomannan chain depolymerization with a reduction in the degree of polymerization (DP) ranging from 7.33% to 48.99%. The water contact angle (WCA) reduced from 110.93° to 95.54°, thus increasing the hydration capacity (36.73–45.90 g/g). These mechanisms diminish the gel viscosity (from 798. 227 cP of UT to 334.65 cP at 230‐60) and the viscoelastic moduli (G′ andG″) indicating the low strength of gels from plasma‐treated galactomannan (PT‐GG). This further influenced the least gelation concentration, foam capacity, and foam stability. However, the critical strain (from 11.83% [UT] to 41% [230‐60]), cross‐over frequency (from 3.39 Hz [UT] to 15.3 Hz [230‐60]), and degradation activation energy (from 18.445 kJ/mol [UT] to 21.721 kJ/mol [230‐60]) of the PT‐GG were increased (from 18.445 kJ/mol [UT] to 21.721 kJ/mol [230‐60]) signifying the increased stability of gels by intramolecular and electrostatic forces. Thus, the cold plasma‐induced depolymerization and hydrophilic modification of galactomannan influence the gelation and functional attributes which widen the potential applications of the hydrocolloid.Practical ApplicationsDepolymerized guar gum is industrially known for its specific applications such as low‐viscosity source of dietary fiber, stabilizers, complex forming, and encapsulating agents. This study shows the potential of cold plasma processing as an eco‐friendly sustainable technology for producing depolymerized guar gum which can be applied as a source of fiber in enteral feed formulations, stabilizers in low viscous spreads and sauces, and also in thermo‐reversible gel networks due to its thermal gel transition attributes.

Curdlan Gum, Properties, Benefits and Applications

Curdlan gum is a new polymer produced by the microbial fermentation of sugar raw materials. It has the unique property of forming a gel under heating conditions and is also called a thermal gel. In 1996, the FDA approved the application of curdlan gum as a food raw material in the food industry. Curdlan gum does not dissolve in water, but it will swell and disperse easily in cold water. It is heated to form a colloid, according to its properties can be divided into low colloid and high colloid. It is produced by heating to 55~65°C and cooling to about 40°C, forming low-grade colloid with thermal reflection. When the water dispersion of cordlan gum is heated to more than 80°C, a higher colloid is formed. The Curdlan gel can reduce the water loss rate of chilled meat products and extend their shelf life.

In vivo tests of a novel wound dressing based on agar aerogel

Aerogels, especially bio-based ones, present a promising option for wound dressing; specifically, because of their low toxicity, high stability, bio-compatibility, and good biological performance. In this study, agar aerogel was prepared and evaluated as novel wound dressing material in an in vivo rat study. Agar hydrogel was prepared by thermal gelation, after that the water inside the gel was exchanged with ethanol, and finally the alcogel was dried by supercritical CO2. The textural and rheological properties of the prepared aerogel were characterized, showing that the prepared agar aerogels possess high porosity (97–98 %), high surface area (250–330 m2g−1) as well as good mechanical properties and easiness of removal from the wound site. The results of the in vivo experiments macroscopically demonstrate the tissue compatibility of the aerogels in dorsal interscapular injured rat tissue and a shorter wound healing time comparable to that of gauze-treated animals. The histological analysis underpins the reorganisation and healing of the tissue for the injured skin of rats treated with agar aerogel wound dressing within the studied time frame.

Thermal gelation of cellulose based suspensions

A more sustainable future calls for bio-based alternatives to replace plastic foams for various applications, such as packaging, insulation and cushioning. Some bio-based foams emerging in scientific publications are fabricated using liquid foam templating and methyl cellulose as well as fibers as main constituents. Scaling up of the production, however, requires a comprehensive understanding of the rheology of the foam during the shaping and drying processes. In this article, we report rheological studies of cellulose based systems in the context of thermal gelation. In more precise terms, we study how the presence of cellulose fibers and other additive materials influences the thermal gelation properties of methyl cellulose. We observe that the rheological properties, while heavily dependent on the material composition, are reasonably adjustable by appropriate material choices. The fibers are seen to decrease the temperature required for methyl cellulose to undergo a viscoelastic transition which is useful in the solid foam fabrication process. We anticipate that in the present application, the fibers increase the stability of the desired structure during the drying stage of the foam.

Experimental study on the heating/cooling and temperature uniformity performance of the microchannel temperature control device for nucleic acid PCR amplification reaction of COVID-19

The nucleic acid detection is an effective way for the prevention and control of COVID-19. PCR amplification is an important process in the nucleic acid detection. At present, PCR amplification has the problem of low heating/cooling rates, and poor temperature uniformity. This paper proposes a microchannel temperature control device for the nucleic acid detection. Five groups of parallel serpentine channels are used to increase the cooling rate of the PCR amplification. A gradual thermal conductivity design is applied to the reaction module to increase the temperature uniformity. The experimental results show that the best temperature uniformity is obtained when the materials of the inner and outer layers of the reaction module are copper and aluminum alloys, respectively. The limit and average heating/cooling rate are 7.2, 6.12, 5.52 and 5.28 °C/s, respectively, when the input power of the thermoelectric cooler is 11.07 W/cm2, the temperature and flow rate of the cooling water are 15℃ and 700 ml/min, and the thermal conductivity of the thermal grease is 6 W/(m·K). Compared with the commercial fan-fin cooling method, the limit and average heating/cooling rates are increased by 38.02%, 80.82%, 86.49% and 208.77%, respectively, with the help of microchannel cooling method.

Development of the production technology of a new highly effective thermal grease

A rapid increase in the power of microelectronic devices, along with a reduction in their size, leads to a rapid growth in the density of dissipated heat flows. As a result, thermal management becomes a crucial factor for maintaining the stable uninterrupted operation of microelectronic devices. Stricter requirements for thermal interface materials (TIMs) make it necessary to optimize their production technology. A solution-based technology for obtaining grease with enhanced thermophysical properties is proposed. It has been shown that heat treatment of a mechanical mixture of aluminum nitride (AlN) and graphite (C) (1:1 by weight) in a vacuum at temperatures of 250–350 °C makes it possible to clean the surface of the particles from moisture and organic impurities, which leads to an increase in the thermal conductivity of the materials obtained. It was revealed that the best solvent at the processing stage is AlN:C silane is ethanol due to the high chemical similarity with silane surfactant. In contrast, when introducing particles into polydimethylsiloxane (PDMS), the highest thermal conductivity results were achieved with acetone as a solvent. The use of ultrasonic treatment of the filler, when introduced into the polymer matrix, was considered. It was shown that the optimal duration is 10 to 15 min, depending on the surfactant. The resulting thermal pastes have sufficient thermal conductivity (up to 2.25 W/(m·K)) and high thermal stability up to the flash point of PDMS (340 °C).

Effect of pH on the thermal gel properties of whey protein isolate-high acyl gellan gum.

Protein-polysaccharide gels have significant and unique properties in food formulations. However, they are susceptible to environmental influences like heat and pH. The present work investigated the effects of acid and alkali treatments on the gel properties and microstructural changes of whey protein isolate (WPI) high acyl gellan gum (HG). The results showed that the pH had a strong effect on the gel hardness, water-holding capacity (WHC), free sulfhydryl groups (-SH), and other properties of the composite gel. The hardness reached a maximum level of 282.50 g and the best WHC was 98.33% at pH7, indicating that a suitable pH could promote this cross-linking between the WPI and HG molecules. The rheological analysis demonstrated that the pH affected the gel formation time. Meanwhile, the gel formation time reached a maximum at pH 7, and the gel's storage modulus G' value was the largest in the final state. Fourier transform infrared spectroscopy (FTIR) results showed that pH affected the interaction between WPI and HG. Scanning electron microscopy (SEM) analysis also indicated that the composite gel formed a three-dimensional network structure at pH 7-9. These results could broaden the application of protein-polysaccharide gels in food and delivery systems. © 2023 Society of Chemical Industry.

Editorial Comment.

No AccessJournal of UrologyAdult Urology23 Feb 2023Editorial Comment Antonio Franc and Riccardo Autorino Antonio FrancAntonio Franc Department of Urology, Rush University, Chicago, Illinois More articles by this author and Riccardo AutorinoRiccardo Autorino Department of Urology, Rush University, Chicago, Illinois More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003185.01AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookLinked InTwitterEmail "Editorial Comment." The Journal of Urology, Publish Ahead of Print, pp. – REFERENCES 1. . Durability of response to primary chemoablation of low-grade upper tract urothelial carcinoma using UGN-101, a mitomycin-containing reverse thermal gel: OLYMPUS trial final report. J Urol.2022; 207(4):779-88. Link, Google Scholar 2. . Primary chemoablation of low-grade upper tract urothelial carcinoma using UGN-101, a mitomycin-containing reverse thermal gel (OLYMPUS): an open-label, single-arm, phase 3 trial. Lancet Oncol.2020; 21(6):776-785. Crossref, Medline, Google Scholar 3. . Efficacy and safety of mitomycin gel (UGN-101) as an adjuvant therapy after complete endoscopic management of upper tract urothelial carcinoma. J Urol.2023; 209(5):000-000. Google Scholar Submitted July 22, 2022; accepted January 10, 2023; published 000. © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Antonio Franc Department of Urology, Rush University, Chicago, Illinois More articles by this author Riccardo Autorino Department of Urology, Rush University, Chicago, Illinois More articles by this author Expand All Submitted July 22, 2022; accepted January 10, 2023; published 000. Advertisement PDF downloadLoading ...

Effects of temperature and ionic strength on the microscopic structure and dynamics of egg white gels.

We investigate the thermal gelation of egg white proteins at different temperatures with varying salt concentrations using x-ray photon correlation spectroscopy in the geometry of ultra-small angle x-ray scattering. Temperature-dependent structural investigation suggests a faster network formation with increasing temperature, and the gel adopts a more compact network, which is inconsistent with the conventional understanding of thermal aggregation. The resulting gel network shows a fractal dimension δ, ranging from 1.5 to 2.2. The values of δ display a non-monotonic behavior with increasing amount of salt. The corresponding dynamics in the q range of 0.002-0.1 nm-1 is observable after major change of the gel structure. The extracted relaxation time exhibits a two-step power law growth in dynamics as a function of waiting time. In the first regime, the dynamics is associated with structural growth, whereas the second regime is associated with the aging of the gel, which is directly linked with its compactness, as quantified by the fractal dimension. The gel dynamics is characterized by a compressed exponential relaxation with a ballistic-type of motion. The addition of salt gradually makes the early stage dynamics faster. Both gelation kinetics and microscopic dynamics show that the activation energy barrier in the system systematically decreases with increasing salt concentration.

Thermal and electrical contact resistances of thermoelectric generator: Experimental study and artificial neural network modelling

Thermal and electrical contact resistances (TCR and ECR) of thermoelectric generator (TEG) exert essential impacts on its performance. In this study, through a series of experiments these two important properties have been estimated in a wide range of thermal and mechanical conditions, and with different interfacial materials. The magnitudes of the overall TCR were found in the range of (1.12–2.00) × 10–3 m2⋅K/W with air, (0.82–1.81) × 10–3 m2⋅K/W with graphene sheet, and (3.61–8.37) × 10–4 m2⋅K/W with thermal grease as interfacial materials when the heat-source temperature varied from 348.15 K to 598.15 K and the imposed pressure load from 266 kPa to 1266 kPa. Importantly, the detailed TCRs at different locations across the TEG system were also analyzed. The dominant components, which occupy more than 80 % of the overall TCR, have been identified at the interfaces of the thermoelectric module contacting the heat source and heat sink. In our experiment, the corresponding ECRs under the same working conditions were (1.03–1.52) × 10–9 Ω⋅m2, (0.56–9.60) × 10–10 Ω⋅m2, and (1.05–6.23) × 10–10 Ω⋅m2, respectively. Moreover, it is revealed that the TEG system delivered better performance at relatively low TCR and ECR when it operated at a high heat-source temperature, a large pressure load and using thermal grease as interfacial material. In addition to these experimental findings, a novel fully-connected feed-forward artificial neural network (ANN) model was also proposed to predict the overall TCR. It is shown that such an ANN model, as a promising approach, can achieve a cost-effective TCR prediction in good accuracy, with the mean square error and correlation coefficient being 2.36 × 10–9 and 99.4 %, respectively. These numerical and experimental results in this study will be of particular value for future TEG design and optimization.

High thermal safety and conductivity gel polymer electrolyte composed of ionic liquid [EMIM][BF4] and PVDF-HFP for EDLCs

Gel-polymer electrolytes (GPEs) are of great interest to build high-performing rechargeable electrical double-layer capacitors (EDLCs) owing to the combination of good electrochemical properties and improved safety. Herein, we report a quasi-solid-state GPE for EDLCs from a mixture of the poly (vinylidene fluoride-co-hexafluoro propylene) (PVDF-HFP) and ionic liquid 1-ethyl-3-methylimidazole tetrafluoroborate ([EMIM][BF4]), which avoids the leakage of liquid electrolyte and the low conductivity of common solid electrolyte. The intermolecular forces of GPE was characterized by in-situ infrared (IR) spectroscopy, and the interactions between ionic liquid and polymer were also analyzed. The prepared GPE was observed to be easily procurable, excellent transparency, high thermal safety (thermal stability up to 320 °C) and outstanding electrochemical properties at room temperature (wide electrochemical stability window of 3.91 V versus SS (SS being stainless steel foils) and high ionic conductivity of 6.9 × 10−3 S cm−1). The specific capacitance, the maximum specific energy, and the maximum specific power of the fabricated symmetrical supercapacitor had been determined to be 161.8 F g−1, 89.89 Wh kg−1, and 8 kW kg−1, respectively. Moreover, the EDLC shows extraordinary electrochemical behaviors and cyclic stability over up to 10 000 cycles at 25 °C with 86% capacitance retention under a current load of 2 A g−1. The experimental results indicate the excellent potential of the [EMIM][BF4] ionic-liquid-based gel polymer electrolyte for EDLCs.

Efficacy and Safety of Mitomycin Gel (UGN-101) as an Adjuvant Therapy After Complete Endoscopic Management of Upper Tract Urothelial Carcinoma.

We describe a novel application of the reverse thermal polymer gel of mitomycin C (UGN-101) as adjuvant therapy after complete endoscopic ablation of upper tract urothelial carcinoma. We retrospectively reviewed patients treated with UGN-101 from 15 high-volume centers. Adjuvant therapy was defined as treatment administered following visually complete endoscopic ablation. Response at primary endoscopic evaluation was defined as no visual tumor or negative biopsy. Ipsilateral disease-free and progression-free survival were estimated by the Kaplan-Meier method. Ureteral stenosis and other adverse events were abstracted from the medical records. Ureteral stenosis was defined as a condition requiring ureteral stent or nephrostomy, or that would typically warrant stent or nephrostomy. Adjuvant UGN-101 after complete endoscopic ablation was used in 52 of 115 (45%) renal units in the oncologic analysis. At first endoscopic evaluation, 36/52 (69%) were without visible disease. At 6.8 months' median follow-up, the ipsilateral disease-free rate was 63%. Recurrence after adjuvant UGN-101 therapy was more likely in multifocal tumors compared to unifocal (HR 3.3, 95% CI 1.07-9.91). Compared with UGN-101 treatment for chemoablation of measurable disease, there were significantly fewer disease detections with adjuvant therapy (P < .001). Ureteral stenosis after UGN-101 was diagnosed in 10 patients (19%) undergoing adjuvant therapy compared to 17 (29%) undergoing chemoablative therapy (P = .28). In patients being considered for UGN-101, maximal endoscopic ablation prior to UGN-101 treatment may result in fewer patients with disease at first endoscopy and possibly fewer adverse events than primary chemoablative therapy. Longer follow-up is needed to determine if UGN-101 after complete endoscopic ablation will lead to durable disease-free interval.

3D Graphene-Nanowire "Sandwich" Thermal Interface with Ultralow Resistance and Stiffness.

Despite the recent advancements of passive and active cooling solutions for electronics, interfaces between materials have generally become crucial barriers for thermal transport because of intrinsic material dissimilarity and surface roughness at interfaces. We demonstrate a 3D graphene-nanowire "sandwich" thermal interface that enables an ultralow thermal resistance of ∼0.24 mm2·K/W that is about 1 order of magnitude smaller than those of solders and several orders of magnitude lower than those of thermal greases, gels, and epoxies, as well as a low elastic and shear moduli of ∼1 MPa like polymers and foams. The flexible 3D "sandwich" exhibits excellent long-term reliability with >1000 cycles over a broad temperature range from -55 °C to 125 °C. This nanostructured thermal interface material can greatly benefit a variety of electronic systems and devices by allowing them to operate at lower temperatures or at the same temperature but with higher performance and higher power density.