Local Concentration Effects Research Articles

Fatigue performance testing and life prediction of welded fuel pipes

The external piping system which connects power devices, valve control devices, actuators, etc. is an essential system on the aero engine. Under the combined effects of high fluid pressure and external vibration, multiaxial fatigue failure is the main factor that seriously affects the safety of the piping system. The objective of this paper is to establish the multiaxial fatigue life model for the typical welded fuel pipe of the piping system by combining fatigue testing, simulation and theoretical analysis which is of great guiding significance for the engineering application of the piping system. Firstly, the fatigue limits of welded fuel pipes under no and 13.5 MPa internal pressure are obtained by rotational bending fatigue tests using the up-and-down method. Three additional stress levels of rotational bending fatigue tests under no internal pressure are supplemented and then the S-N curve is further obtained by the group method. Since the corresponding fracture surface of the specimens locates at the weld toe near the fixed end, peak stress method is adopted to evaluate the fatigue performance of the weld toe on the pipe specimens. In addition, by comparing the fatigue limit with no and 13.5 MPa internal pressured pipes, it is obvious that the equivalent uniaxial stress corrected by Gerber formula is not applicable for the multiaxial fatigue condition which is caused by the combined effect of fluid pressure and displacement load. The local stress concentration factor caused by the weld toe is determined and based on Findley critical plane model, the multiaxial fatigue life model is established which simultaneously takes the local stress concentration effect, mean stress effect and multiaxial stress effect into consideration. The results of rotational bending fatigue tests under 13.5 MPa internal pressure are within the triple error dispersion band and the accuracy of the proposed life model are verified.

Composite RGO/Ag/Nanosponge Materials for the Photodegradation of Emerging Pollutants from Wastewaters.

Some composite materials have been prepared, constituted by a cyclodextrin-bis-urethane-based nanosponge matrix in which a reduced graphene oxide/silver nanoparticles photocatalyst has been dispersed. Different chain extenders were employed for designing the nanosponge supports, in such a way as to decorate their hyper-cross-linked structure with diverse functionalities. Moreover, two different strategies were explored to accomplish the silver loading. The obtained systems were successfully tested as catalysts for the photodegradation of emerging pollutants such as model dyes and drugs. Enhancement of the photoactive species performance (up to nine times), due to the synergistic local concentration effect exerted by the nanosponge, could be assessed. Overall, the best performances were shown by polyamine-decorated materials, which were able to promote the degradation of some particularly resistant drugs. Some methodological issues pertaining to data collection are also addressed.

Study on the influence of thermo-pressure coupling environment on the fracture properties of shale in deep reservoirs

Deep reservoir in-situ environments enhance rock plasticity. Most current experiments that combine temperature and pressure are difficult to observe the crack tip directly, impeding the understanding of deep rock fracture properties. This paper used a digital image correlation method and the principle of fracture mechanics to establish an innovative visual experimental rock fracture system with in-situ environment. Crack tip initiation and propagation were captured dynamically in real-time temperature and pressure coupling conditions, and the influence on shale fracture properties was analyzed, providing a feasible method for examining the fracture behavior of deep reservoir rocks. The results showed that the fracture characteristics of deep shale should be reflected and characterized by jointly considering temperature and confining pressure. Shale plasticity produced crack tip passivation in combined in-situ temperature and pressure conditions, and reduced the local stress concentration effect. The post-peak softening relationship showed a nonlinear “convex” trend, indicating nonlinear fracture characteristics with increased toughness. The exponential coefficient representing the degree of nonlinearity rose as the buried depth increased. The exponential coefficient related to the buried depth was introduced to modify the constitutive model, which was used to effectively characterize the nonlinear fracture behavior of deep reservoirs and provide a basis for deep reservoir fracturing reform research.

DNA tetrahedral nanostructure-corbelled DNA walker for intramolecular electrochemiluminescence resonance energy transfer sensing of tumor exosomes

Exosomes as new noninvasive biomarkers play a prominent role in early cancer diagnosis, but tumor-derived exosomes are difficult to detect upon tumor initiation because of their low levels. Herein, we proposed a novel and stable strategy for exosomes detection based on intramolecular electrochemiluminescence resonance energy transfer (ECL-RET) and DNA tetrahedral nanostructures (DTNs)-corbelled DNA walker. To enhance the ECL efficiency of luminophores, abundant Ru(bpy)32+ molecules were coordinatively immobilized on Zr12-adb nanoplates (NPs) to form Ru-Zr12-adb NPs. So, high ECL-RET efficiency based on the combination of Zr12-adb NPs (donor) and Ru(bpy)32+ (acceptor) into one nanostructure resulted in considerably enhanced ECL response. Impressively, DNA walker with six track strands supported by DTNs demonstrated enhanced walking speed and high reaction efficiency because of the improved local concentration and space confinement effect of DTNs. In consequence, this as-designed ingenious ECL biosensor exhibited excellent sensing performance for exosomes.

Piezoresistive behavior of elastomer composites with segregated network of carbon nanostructures and alumina

Electrically conductive elastomer composites (CECs) with segregated networks of conductive nanofillers show high potential in stretchable strain sensors due to balanced mechanical and electrical properties, yet the sensitivity at low strain is generally insufficient for practical application. Herein, we report an easy and effective way to improve the resistive response to low strain for CECs with segregated network structure via adding stiff alumina into carbon nanostructures (CNS). The CEC containing 0.7 ​wt% CNS and 5 ​wt% Al 2 O 3 almost sustains the same elasticity (elongation at break of ∼900%) and conductivity (0.8 ​S/m) as the control, while the piezoresistive sensitivity is significantly improved. Thermoplastic polyurethane (TPU) composites with a segregated network of hybrid nanofillers (CNS and Al 2 O 3 ) show much higher strain sensitivity (Gauge factor, GF ​= ​566) at low strain (45% strain) due to a local stress concentration effect, this sensitivity is superior to that of TPU/CNS composites (GF ​= ​11). Such a local stress concentration effect depends on alumina content and its distribution at the TPU particle interface. In addition, CECs with hybrid fillers show better reproducibility in cyclic piezoresistive behavior testing than the control. This work offers an easy method for fabricating CECs with a segregated filler network offering stretchable strain sensors with a high strain sensitivity.

Deciphering Reversible Homogeneous Catalysis of the Electrochemical H2 Evolution and Oxidation: Role of Proton Relays and Local Concentration Effects**

AbstractNickel bisdiphosphine complexes bearing pendant amines form a unique series of catalysts (so‐called DuBois’ catalysts) capable of bidirectional/reversible electrocatalytic oxidation and production of dihydrogen. This unique behaviour is directly linked to the presence of proton relays installed close to the metal center. We report here for the arginine derivative [Ni(P2CyN2Arg)2]6+ on a mechanistic model and its kinetic treatment that may apply to all DuBois’ catalysts and show that it allows for a good fit of experimental data measured at different pH values, catalyst concentrations and partial hydrogen pressures. The bidirectionality of catalysis results from balanced equilibria related to hydrogen uptake/evolution on one side and (metal)‐hydride installation/capture on the other side, both controlled by concentration effects resulting from the presence of proton relays and connected by two square schemes corresponding to proton‐coupled electron transfer processes. We show that the catalytic bias is controlled by the kinetic of the H2 uptake/evolution step. Reversibility does not require that the energy landscape be flat, with redox transitions occurring at potentials up to 250 mV away for the equilibrium potential, although such large deviations from a flat energy landscape can negatively impacts the rate of catalysis when coupled with slow interfacial electron transfer kinetics.

Deciphering Reversible Homogeneous Catalysis of the Electrochemical H2 Evolution and Oxidation: Role of Proton Relays and Local Concentration Effects.

Nickel bisdiphosphine complexes bearing pendant amines form a unique series of catalysts (so-called DuBois' catalysts) capable of bidirectional/reversible electrocatalytic oxidation and production of dihydrogen. This unique behaviour is directly linked to the presence of proton relays installed close to the metal center. We report here for the arginine derivative [Ni(P2 Cy N2 Arg )2 ]6+ on a mechanistic model and its kinetic treatment that may apply to all DuBois' catalysts and show that it allows for a good fit of experimental data measured at different pH values, catalyst concentrations and partial hydrogen pressures. The bidirectionality of catalysis results from balanced equilibria related to hydrogen uptake/evolution on one side and (metal)-hydride installation/capture on the other side, both controlled by concentration effects resulting from the presence of proton relays and connected by two square schemes corresponding to proton-coupled electron transfer processes. We show that the catalytic bias is controlled by the kinetic of the H2 uptake/evolution step. Reversibility does not require that the energy landscape be flat, with redox transitions occurring at potentials up to 250 mV away for the equilibrium potential, although such large deviations from a flat energy landscape can negatively impacts the rate of catalysis when coupled with slow interfacial electron transfer kinetics.

Reproduction of bacterial chemotaxis by a non-living self-propelled object

Taxic behavior as a response to an external stimulus is a fundamental function of living organisms. Some bacteria successfully implement chemotaxis without directly controlling the direction of movement. They periodically alternate between run and tumble, i.e., straight movement and change in direction, respectively. They tune their running period depending on the concentration gradient of attractants around them. Consequently, they respond to a gentle concentration gradient stochastically, which is called “bacterial chemotaxis.” In this study, such a stochastic response was reproduced by a non-living self-propelled object. We used a phenanthroline disk floating on an aqueous solution of Fe^{2+}. The disk spontaneously alternated between rapid motion and rest, similar to the run-and-tumble motion of bacteria. The movement direction of the disk was isotropic independent of the concentration gradient. However, the existing probability of the self-propelled object was higher at the low-concentration region, where the run length was longer. To explain the mechanism underlying this phenomenon, we proposed a simple mathematical model that considers random walkers whose run length depends on the local concentration and direction of movement against the gradient. Our model adopts deterministic functions to reproduce the both effects, which is instead of stochastic tuning the period of operation used in the previous reports. This allows us to analyze the proposed model mathematically, which indicated that our model reproduces both positive and negative chemotaxis depending on the competition between the local concentration effect and it’s gradient effect. Owing to the newly introduced directional bias, the experimental observations were reproduced numerically and analytically. The results indicate that the directional bias response to the concentration gradient is an essential parameter for determining bacterial chemotaxis. This rule might be universal for the stochastic response of self-propelled particles in living and non-living systems.

Reduced graphene oxide/silver nanoparticles/β-cyclodextrin nanosponges composites with improved photocatalytic activity

Significant activity improvement was achieved by associating graphene oxide-silver composite photocatalysts with cyclodextrin-based nanosponge materials, due to the synergistic effect provided by the supramolecular host abilities of the nanosponge. Three photocatalysts were prepared, fully characterized (FT-IR, ss-NMR, Raman, XRD, SEM, EDX, AFM, ICP, TGA, potentiometric titration), and tested for the oxidative photodegradation of some dyes and phenols, chosen as model organic pollutants. Compared to the unsupported photocatalyst, the nanosponge-based materials showed enhanced performances (being able to carry out the degradation even of dyes which do not react in the presence of the unsupported catalyst), and good recyclability. The activity improvement is attributed to a local concentration effect provided by the nanosponge, able to capture the organic substrate in the proximity of the actual photocatalyst. The results presented herein provide a helpful basis for designing advanced catalytic systems.

Interior micro‐defect induced cracking mechanism and life prediction of carburized Cr−Ni steel based on double nonlinear damage under variable amplitude loading

AbstractThe constant/variable amplitude loading fatigue test with interior inclusion‐fine granular area‐fisheye induced failure under R=0 were carried out on carburized Cr−Ni steel. The results showed that the fatigue life under variable amplitude loading is longer than that under constant amplitude loading in very‐high‐cycle fatigue regime under same maximum stress level, and the surface morphology of fine granular area under variable amplitude loading is coarser than that under constant amplitude loading under same order of magnitude of fatigue life. Simultaneously, it can be determined that the formation micro‐mechanism of fine granular area is caused by the continuous deboning due to stress concentration around interior micro‐defects. Furthermore, the life prediction model based on double nonlinear fatigue damage, which considers the coupling effect of local equivalent stress (surface residual stress and local stress concentration effect), loading sequence, failure mechanism and nonlinear characteristics of fatigue damage under constant/variable amplitude loading is established, and predicted life has good accuracy within the factor‐of‐three lines.

Bank on it: Do Local Banks Contribute to Rural Community Prosperity?*

AbstractRecent research on the restructuring of the financial industry from local banks to interstate conglomerates has raised questions about the impact on nonmetropolitan economies. In this paper, we develop two competing hypotheses and scrutinize the impact of local bank concentration (percent banks that are locally headquartered) on four measures of economic growth from 1980 to 2010 in metropolitan, micropolitan, and non‐core Commuting Zones (CZs). We employ fixed effects panel regression models for the 1980–2010 time frame. We find that local bank concentration is positively related to business births and establishment dynamics in non‐core and micropolitan CZs. The effects of local banking on measures of income and wages fail to show consistent effects. There are no positive local banking concentration effects on economic growth in metropolitan CZs during this time frame. Implications for theory, research, and policy are discussed.

High-Efficiency 3D DNA Walker Immobilized by a DNA Tetrahedral Nanostructure for Fast and Ultrasensitive Electrochemical Detection of MiRNA.

Herein, by directly limiting the reaction space, an ingenious three-dimensional (3D) DNA walker (IDW) with high walking efficiency is developed for rapid and sensitive detection of miRNA. Compared with the traditional DNA walker, the IDW immobilized by the DNA tetrahedral nanostructure (DTN) brings stronger kinetic and thermodynamic favorability resulting from its improved local concentration and space confinement effect, accompanied by a quite faster reaction speed and much better walking efficiency. Once traces of target miRNA-21 react with the prelocked IDW, the IDW could be largely activated and walk on the interface of the electrode to trigger the cleavage of H2 with the assistance of Mg2+, resulting in the release of amounts of methylene blue (MB) labeled on H2 from the electrode surface and the obvious decrease of the electrode signal. Impressively, the IDW reveals a conversion efficiency as high as 9.33 × 108 in 30 min with a much fast reaction speed, which is at least five times beyond that of typical DNA walkers. Therefore, the IDW could address the inherent challenges of the traditional DNA walker easily: slow walking speed and low efficiency. Notably, the IDW as a DNA nanomachine was utilized to construct a sensitive sensing platform for rapid miRNA-21 detection with a limit of detection (LOD) of 19.8 aM and realize the highly sensitive assay of biomarker miRNA-21 in the total RNA lysates of cancer cell. The strategy thus helps in the design of a versatile nucleic acid conversion and signal amplification approach for practical applications in the areas of biosensing assay, DNA nanotechnology, and clinical diagnosis.

Formulation, characterization of glucosamine loaded transfersomes and in vivo evaluation using papain induced arthritis model

The aim of current study was to develop the transdermal transfersomes of glucosamine for better drug delivery. Stretch ability and plasticity of transfersomes membranes mitigate the risk of vesicle rupture in the skin and allows the drug carrying transfersome to pass through the epidermis following the natural water gradient. Transdermal delivery of Glucosamine has an advantage over oral route, having greater local concentration and fewer systemic effects. Thin Film Rotary method was use to prepare transfersomes, and characterization was carried out physio-chemically using electron microscopic studies, zeta potential evaluation, entrapment efficiency studies. To add on in the stability, development of a secondary topical vehicle using Carbopol 940 was carried out to enhance the shelf life of transfersomes. Furthermore, in vivo studies on rabbits were also carried out using the papain induced arthritis model to support the effectiveness of treatment. The radiology studies of knee joint of rabbits proved the effectiveness of glucosamine loaded transfersomes in healing the osteoarthritis with the blood plasma analysis remain unaltered. In vitro characterization showed the successful development of nano-deformable entities with good entrapment efficiency but with little stability, therefore modified into a gel. In a nut shell this modified new dosage from can be best alternative to other conventional options that owe lot of demerits.

Synthesis, Characterization and Release Studies of Ethylene Diamine Tetraacetic Acid (EDTA)-Antimicrobial Drug Conjugates for Colon Release

Background: The colon targeted drug delivery system is mainly useful for the topical treatment of colon diseases such as ulcerative colitis, Crohn’s disease OR colorectal cancers where we attain high local concentration and minimum side effects. In the present study we have synthesized some colon targeted Ethylene diamine tetra acetic acid (EDTA)-antimicrobial drug conjugates. Objectives: The goal of synthesizing EDTA-antimicrobial drug conjugates are that they reach intact in the colon and not be absorbed in the upper GIT, this is because of high molecular weight (>500) of the conjugates (Lipinski’s rule of 5). Materials and Methods: A series of EDTA-antimicrobial drug conjugates (E1-E5) were synthesized by stirring tetra sodium EDTA with antimicrobial drugs viz. Metronidazole (MTZ), Ornidazole (OZ), Ciprofloxacin (CF), Norfloxacin (NF) and Sulfamethoxazole (SM) in presence of EDAC ((1-ethyl-3(3-dimethylaminopropyl) carbodiimide). All the synthesized conjugates were characterized by FTIR, NMR (1H and 13C), Mass spectrometry and elemental analysis to identify structural components. The synthesized conjugates were screened for antimicrobial (antibacterial) and colon release studies. Results and Discussion: On the basis of chemical and spectral analysis EDTA-antimicrobial drug conjugates were synthesized and synthesized conjugates showed good antimicrobial (antibacterial) activity against tested stains. In-vitro release studies of the synthesized conjugates of the series have shown good release results which indicates that synthesized conjugates release the parent drug (antimicrobial drugs) to the colon. Conclusion: Synthesized conjugates improve drug delivery to the intestinal region. Release studies result suggest that the drugs begin to release from the conjugates in the distal intestinal region and appreciable release in the colon has been observed.

Selective Transport in the Nuclear Pore Complex

Nuclear pore complexes (NPCs) mediate nucleocytoplasmic exchange controlling the flow of molecules into and out of the nucleus. The selective filter properties of NPCs enable translocation of specific molecules known as nuclear transport factors (NTRs) and their cargo. Central to this selectivity barrier is a group of largely intrinsically disordered nucleoporins (Nups) that contain multiple phenylalanine‐glycine repeats, termed FG Nups. The interactions between FG Nups and NTRs enable NTRs to translocate rapidly yet selectively through the NPC in what is referred to as the “transport paradox”. FG Nups in the NPC have a small folded anchor region tethering them to the NPC outer ring and otherwise are fully disordered, random coil polymers that remain predominantly disordered while engaged to NTRs. FG Nups interact with NTRs using mainly their FG motifs and minimally their intervening spacer residues. The overall enthalpy of the interaction increases as multivalency increases the frequency of individually weak FG‐NTR contacts. Tight binding is limited by an entropy penalty that disfavors simultaneous engagements of FG motifs. Small angle neutron scattering (SANS) shows that the entropy loss is partly due to the local rigidity of an FG motif in the interacting state(Fig 1). All‐atom molecular dynamics (MD) simulation indicates that spacers between the FG motifs behave as “entropic springs”, disfavoring any static binding of the FG repeats. The dynamics of FG Nups enables the FG motifs to slide along the hydrophobic patches of NTRs enabling FG motifs to be easily displaced by other competing FG motifs (Fig. 2). This explanation provides a simple hypothesis for the rapid exchange of FG motif contacts during transport, focusing on the entropic exclusion of non‐NTRs, and ‘solubilization’ of NTR complexes, in contrast to possible condensate formation which would provide a compartmentalization of components. These results reveal fundamental aspects of the functioning mechanisms underlying NPC transport at high structural resolution, something lacking in current models of nuclear transport.1. Sparks, S., et al., Analysis of Multivalent IDP Interactions: Stoichiometry, Affinity, and Local Concentration Effect Measurements. Methods Mol Biol, 2020. 2141: p. 463‐475.2. Sparks, S., et al., Deciphering the “Fuzzy” Interaction of FG Nucleoporins and Transport Factors Using Small‐Angle Neutron Scattering. Structure, 2018. 26(3): p. 477‐484 e4.3. Hayama, R., et al., Thermodynamic characterization of the multivalent interactions underlying rapid and selective translocation through the nuclear pore complex. J Biol Chem, 2018. 293(12): p. 4555‐4563.4. Hough, L.E., et al., The molecular mechanism of nuclear transport revealed by atomic‐scale measurements. Elife, 2015. 4.5. Raveh, B., et al., Slide‐and‐exchange mechanism for rapid and selective transport through the nuclear pore complex. Proc Natl Acad Sci U S A, 2016. 113(18): p. E2489‐97.

Local concentration effect on nano-electrocatalytic CO2 reduction

Electrocatalytic CO2 reduction reaction (CO2RR) powered by renewable electricity offers an efficient way of capturing CO2 from the environment to mitigate the climate challenge and produce carbon-neutral hydrocarbon fuels. As the electrocatalysts downsize to the nanoscale, the effect of local concentration around catalysts turns to be significant for the performance of CO2 reduction. Herein, we review nanoscale local concentration effect on electrocatalytic CO2RR by summing up some recent related catalyst design strategies and their underlying mechanisms, providing a perspective for future catalyst design taking such an effect into account.

Sports-based Entertainment and Crime Evidence from Football Games in Brazil

I investigate the relationship between sports-based entertainment and crime using nine years of hourly data on robberies and thefts by police district in São Paulo linked to information on 430 football matches. Results report a citywide voluntary incapacitation impact and a local spatial concentration effect. Robberies significantly drop during matches, especially high-audience ones. Around the stadiums, this effect is outweighed by that of concentration. While I find no evidence of spatial displacement, temporal displacement is at play, with offenses being moved up to pre-game time. I show that the game-crime link is likely deployed through potential criminals rather than victims.

An investigation on the deterioration of physical and mechanical properties of granite after cyclic thermal shock

As one of the main thermal storage medium of hot dry rock geothermal resources, granite is often subject to frequent thermal shock during the geothermal exploitation. Grasping the response regularity of granite to thermal shock is of great significance to the construction and long-term reliability evaluation of enhanced geothermal system (EGS). This paper investigated the physical and mechanical properties of granite after 0∼20 thermal shocks, and discussed its internal deterioration mechanism. Combined with ANSYS numerical simulation analysis, the mechanical formation mechanism of thermal cracks that lead to the deterioration of physical and mechanical properties of granite was analyzed. The results show that the first thermal shock tends to cause the severest deterioration to both physical and mechanical properties of granite. But when the number of thermal shocks exceeds 10, the deterioration slows down. The increase in contact thermal resistance between mineral particles after cyclic thermal shock results in a decrease in the thermal conductivity of granite. The enhancement of local stress concentration effect and the increase of local bearing capacity difference of granite after cyclic thermal shock result in the decrease of peak strength and the enhancement of ductility characteristics of granite. Due to the existence of thermal cracks, the granite after cyclic thermal shock has one more path to release the energy stored during the loading process than the natural granite. Therefore, the maximum counts at the beginning of crack propagation and the entire crack propagation stage are smaller than that of the natural granite. During the thermal shock, the huge instantaneous temperature difference between the interior and exterior of granite leads to the formation of thermal stress, which increases rapidly and then disappears gradually. As a result, the interior of granite mainly bears the effect of the vertical compressive thermal stress up to 7.59 MPa, while the exterior of granite mainly bears the effect of vertical tensile thermal stress up to 9.18 MPa. The propagation of some pre-existing micro cracks with proper orientation in the interior of granite and the initiation and propagation of secondary thermal cracks on granite surface are identified as two main causes to the deterioration of the physical and mechanical properties of granite after cyclic thermal shock.

Study of the adherence of Escherichia coli 83972 on α-biphenyl mannoside-presenting PDMS surfaces

The local concentration effect on the adherence of Escherichia coli 83972 was evaluated using mannosylated PAMAM dendrimers with varying concentrations to immobilize on the surfaces. Results showed no enhancement in adherence by Escherichia coli 83972 using a high local concentration of biphenyl mannoside immobilized on the PAMAM surfaces. The separation distance rather than the local multivalency of the ligand-receptor binding plays an essential role in this system. A vertical orientation of bacteria during the initial binding process was proposed that allows the mobility of bacteria to efficiently survey the environment for potential binding sites.

Design and Evaluation of Dissolving Microneedles for Enhanced Dermal Delivery of Propranolol Hydrochloride.

Oral propranolol hydrochloride has been the first-line treatment for infantile hemangioma (IH), whereas systemic exposure to propranolol has the potential of causing serious adverse reactions. Dermal delivery of propranolol is preferable due to high local drug concentration and fewer adverse effects. However, propranolol hydrochloride (BCS class I) is highly hydrophilic and has difficulty in penetrating the stratum corneum (SC) barrier. Dissolving microneedles (MNs) are an efficient tool for overcoming the barrier of the SC and enhancing dermal drug delivery. In this study, propranolol hydrochloride-loaded dissolving MNs were fabricated by using hyaluronic acid and polyvinyl pyrrolidone as matrix materials. Controllable drug loading in needle tips was achieved by a two-step casting procedure. The needles were good in mechanical strength for penetrating the SC while presented excellent dissolving capability for releasing propranolol hydrochloride. In comparison with the solution counterpart, irrespective of being applied to intact skin or solid MNs-pretreated skin, dissolving MNs significantly increased the permeability and skin retention of propranolol. In conclusion, dissolving MNs could be a potential approach for enhancing dermal delivery of propranolol to treat IH.