Slow Initiation Research Articles

Characterising vascular cognitive impairment compared to cognitively healthy ageing with respect to reaction time, the intra‐individual variability of RT, and error production, practice effects and the task used in their measurement

AbstractBackgroundTo improve the characterisation and the understanding of VCI by examining reaction time (RT), the intra individual variability of RT (IIV), errors, practice, the effects of processing load (e.g. the influence of distracting information) and the effects of hesitancy in cognitively healthy (CH) ageing compared to patients with Subcortical Ischaemic VCI (SIVCI). In addition, the potential influence of the task used to measure these factors upon these results was investigated. The DSM5 requires a measure of brain processing speed to aid in the diagnosis of vascular dementia, but there is no indication of which test to use.MethodTasks comprised of the Trail Making Task (TMT), a clinical test used to measure RT, a visual search task, commonly used in research to measure RT, IIV, errors the effect of distracting information and practice, and an iPad based test ‘iReact’ used to measure hesitancy in response to a stimuli, in the same group of participants. Finally, for the SIVCI group, task performance was investigated with respect to the level of CT or MRI‐visible white matter disease.ResultResults were test dependent, for the TMT results revealed poor completion rates, with 75% of VCI being unable to complete, results also differed depending on analysis used. The visual search task revealed a greater range of results; RT, IIV, errors production and the effect of distracters were significantly worse for those with SVCI compared to CH adults. iReact test results revealed that SIVCI were significantly more hesitant and varied in their response than CH adults. White matter disease was also identified as a poor marker of cognitive function, possibly due to silent lesions, and that RT related function is a better indicator of brain function.ConclusionSubcortical Ischaemic Vascular Cognitive Impairment is characterised by slowed RT, Increased IIV, detrimental effect of distracting information, raised error production, lack of positive practice effects on IIV, very slow response initiation and disproportionately high IIV in response initiation.

Effect of Periodic Overloads on Short Fatigue Crack Behavior in CuNi2Si Alloy under Rotating Bending Load

In this study, the short fatigue crack behavior in a precipitation-strengthened CuNi2Si alloy was investigated using a replica technique under rotating bending loads with periodic overloads, an overload ratio of 1.5, and the stress ratio of both was R = −1. The results show that all the fatigue cracks originated from the surface of the specimen and displayed a trend of slow initiation and then rapid propagation. The introduction of overloads significantly reduced the fatigue crack initiation time and the fatigue life of the sample. The average life of the overloaded samples was only 31% that of the constant load samples. For overload specimens, multiple cracks grew at the same time and merged at different stages, causing the crack length to increase instantaneously after they merged, thereby considerably reducing the fatigue life. Fractographical analysis and observation of the surface-etched sample replica film showed that cracks in samples with and without overload both propagated along the grain boundaries.

Robust Methods to Detect Abnormal Initiation in the Gastric Slow Wave from Cutaneous Recordings.

Upper gastrointestinal (GI) disorders are highly prevalent, with gastroparesis (GP) and functional dyspepsia (FD) affecting 3% and 10% of the US population, respectively. Despite overlapping symptoms, differing etiologies of GP and FD have distinct optimal treatments, thus making their management a challenge. One such cause, that of gastric slow wave abnormalities, affects the electromechanical coordination of pacemaker cells and smooth muscle cells in propelling food through the GI tract. Abnormalities in gastric slow wave initiation location and propagation patterns can be treated with novel pacing technologies but are challenging to identify with traditional spectral analyses from cutaneous recordings due to their occurrence at the normal slow wave frequency. This work advances our previous work in developing a 3D convolutional neural network to process multi-electrode cutaneous recordings and successfully classify, in silico, normal versus abnormal slow wave location and propagation patterns. Here, we use transfer learning to build a method that is robust to heterogeneity in both the location of the abnormal initiation on the stomach surface as well as the recording start times with respect to slow wave cycles. We find that by starting with training lowest-complexity models and building complexity in training sets, transfer learning one model to the next, the final network exhibits, on average, 80% classification accuracy in all but the most challenging spatial abnormality location, and below 5% Type-I error probabilities across all locations.

Fatigue Crack Growth Behaviour of Precipitate-Strengthened CuNi2Si Alloy under Different Loading Modes

In this study, fatigue crack tests of CuNi2Si alloys using the replica technique under symmetrical tensile-compression loading, and rotational-bending loading were carried out with the same nominal stress amplitude. Observation and analysis results indicate that under different load types, the cracks display a trend of slow initiation growth and then rapid growth. The critical point is identified at the approximate value of 0.8 of the fatigue life fraction, and the crack growth rate of the sample under tensile-compression load is approximately an order of magnitude higher than that under rotational-bending load, resulting in the average life of the former being significantly shorter than the latter. Combining the observation results of the fractographical analysis and the surface-etched sample replica film, it can be seen that whether it is a tensile-compression load or a rotational-bending load, cracks mainly propagate in intergranular mode after initiation.

Towards Successes in the Management of Nonconvulsive Status Epilepticus: Tracing the Detection-to-Needle Trajectories.

Data on the timeliness of emergent medication delivery for nonconvulsive status epilepticus (NCSE) are currently lacking. Retrospective chart reviews (between 2015 and 2018) and analyses of all patients with NCSE were performed at the University of Nebraska Medical Center, a level 4 epilepsy center, to determine the latencies to order and administration of the first, second, and third antiepileptic drugs (AEDs). Recurrent NCSE cases were considered independently and classified as comatose and noncomatose. There were 77 occurrences of NCSE in 53 patients. The first, second, and third AEDs were delivered with substantial delays at median times of 80 (25%-75% interquartile range, 44-166), 126 (interquartile range, 67-239), and 158 minutes (interquartile range, 89-295), respectively, from seizure detection. The median times to the order of the first and second AEDs were 33 and 134.5 minutes longer in comatose NCSE patients compared with those with noncomatose forms, respectively (P = 0.001 and 0.004, respectively). The median times between the AED orders and their administration in these two groups were the same (P = 0.60 and 0.37, respectively). With bivariate analysis, the median latencies to administration of the first, second, and third AEDs were significantly increased by 33, 109.5, and 173 minutes, respectively, in patients who died within 30 days compared with those who survived (P = 0.047, P = 0.02, P = 0.0007, respectively). The administration of the first, second, and third AEDs for NCSE was delayed. Slow initiation of acute treatment in comatose patients was caused by delays in the placement of the medication order.

Mechanism of Rate Acceleration of Radical C-C Bond Formation Reaction by a Radical SAM GTP 3',8-Cyclase.

While the number of characterized radical S-adenosyl-l-methionine (SAM) enzymes is increasing, the roles of these enzymes in radical catalysis remain largely ambiguous. In radical SAM enzymes, the slow radical initiation step kinetically masks the subsequent steps, making it impossible to study the kinetics of radical chemistry. Due to this kinetic masking, it is unknown whether the subsequent radical reactions require rate acceleration by the enzyme active site. Here, we report the first evidence that a radical SAM enzyme MoaA accelerates the radical-mediated C-C bond formation. MoaA catalyzes an unprecedented 3',8-cyclization of GTP into 3',8-cyclo-7,8-dihydro-GTP (3',8-cH2GTP) during the molybdenum cofactor (Moco) biosynthesis. Through a series of EPR and biochemical characterizations, we found that MoaA catalyzes a shunt pathway in which an on-pathway intermediate, GTP C-3' radical, abstracts H-4' atom from (4'R)-5'-deoxyadenosine (5'-dA) to transiently generate 5'-deoxyadenos-4'-yl radical (5'-dA-C4'•) that is subsequently reduced stereospecifically to yield (4'S)-5'-dA. Detailed kinetic characterization of the shunt and the main pathways provided the comprehensive view of MoaA kinetics and determined the rate of the on-pathway 3',8-cyclization step as 2.7 ± 0.7 s-1. Together with DFT calculations, this observation suggested that the 3',8-cyclization by MoaA is accelerated by 6-9 orders of magnitude. Further experimental and theoretical characterizations suggested that the rate acceleration is achieved mainly by constraining the triphosphate and guanine base positions while leaving the ribose flexible, and a transition state stabilization through H-bond and electrostatic interactions with the positively charged R17 residue. This is the first evidence for rate acceleration of radical reactions by a radical SAM enzyme and provides insights into the mechanism by which radical SAM enzymes accelerate radical chemistry.

Neurofeedback-Linked Suppression of Cortical β Bursts Speeds Up Movement Initiation in Healthy Motor Control: A Double-Blind Sham-Controlled Study.

Abnormally increased β bursts in cortical-basal ganglia-thalamic circuits are associated with rigidity and bradykinesia in patients with Parkinson's disease. Increased β bursts detected in the motor cortex have also been associated with longer reaction times (RTs) in healthy participants. Here we further hypothesize that suppressing β bursts through neurofeedback training can improve motor performance in healthy subjects. We conducted a double-blind sham-controlled study on 20 human volunteers (10 females) using a sequential neurofeedback-behavior task with the neurofeedback reflecting the occurrence of β bursts over sensorimotor cortex quantified in real time. The results show that neurofeedback training helps healthy participants learn to volitionally suppress β bursts in the sensorimotor cortex, with training being accompanied by reduced RT in subsequent cued movements. These changes were only significant in the real feedback group but not in the sham group, confirming the effect of neurofeedback training over simple motor imagery. In addition, RTs correlated with the rate and accumulated duration of β bursts in the contralateral motor cortex before the go-cue, but not with averaged β power. The reduced RTs induced by neurofeedback training positively correlated with reduced β bursts across all tested hemispheres. These results strengthen the link between the occurrence of β bursts in the sensorimotor cortex before the go-cue and slowed movement initiation in healthy motor control. The results also highlight the potential benefit of neurofeedback training in facilitating voluntary suppression of β bursts to speed up movement initiation.SIGNIFICANCE STATEMENT This double-blind sham-controlled study suggested that neurofeedback training can facilitate volitional suppression of β bursts in sensorimotor cortex in healthy motor control better than sham feedback. The training was accompanied by reduced reaction time (RT) in subsequent cued movements, and the reduced RT positively correlated with the level of reduction in cortical β bursts before the go-cue, but not with average β power. These results provide further evidence of a causal link between sensorimotor β bursts and movement initiation and suggest that neurofeedback training could potentially be used to train participants to speed up movement initiation.

Chemoselective Polymerization of Epoxides from Carboxylic Acids: Direct Access to Esterified Polyethers and Biodegradable Polyurethanes.

Carboxylic-acid-initiated ring-opening polymerization (ROP) of epoxides is a fast approach to esterified polyethers which are cleavable at the termini or centers. A major challenge lies in conventional ROP methods because of the lability of ester groups formed in the initiation step. Here, we describe chemoselective ROP of epoxides from aliphatic, aromatic, and methacrylic carboxylic acids using two-component metal-free catalysts. Transesterification is clearly absent so that well-defined α-(carboxylic ester)-ω-hydroxy polyethers are generated in one step from monocarboxylic acids. The livingness of the ROP is verified despite the slow initiation mode. The ester end group can be readily cleaved from the polyether hydrolytically. An α,ω-dihydroxy poly(propylene oxide) with two central ester groups is generated from a diacid initiator and transformed in situ by the same catalyst to polyurethane which shows distinct enzymatic degradability. This study provides convenient access to α,ω-heterobifunctional polyethers with cleavable, releasable, or modifiable end groups and to biodegradable polyether-based materials.

Synthesis of molecular‐weight‐controlled polyfluorene with boronate at one end

ABSTRACTWe investigated the synthesis of polyfluorene with a pinacol boronate (PinB) moiety at one end and with controlled molecular weight by means of Suzuki–Miyaura coupling polymerization of pinacol (7‐bromo‐9,9‐dioctyl‐9H‐fluoren‐2‐yl)boronate (1) with a palladium(0) precatalyst in the presence of pinacol 4‐trifluoromethylphenylboronate (2) as a chain terminator and CsF/18‐crown‐6 as a base. When we used AmPhos Pd G2, which has a propensity for intramolecular catalyst transfer on a π‐electron face, polyfluorene with the PinB moiety at one end and PhCF3 (derived from 2) at the other end was obtained, and the molecular weight increased in proportion to the feed ratio of [1]0/[catalyst]0, though the molecular weight distribution was broad. Since the molecular weight also linearly increased with respect to the conversion of 1 until the middle stage of polymerization, the polymerization appears to involve chain‐growth polymerization through intramolecular catalyst transfer from the Pd catalyst inserted into the CBr bond of 1. The broad molecular weight distribution might be mainly due to slow initiation and slow termination with 2, rather than polymer–polymer coupling. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2498–2504

End-group functionalization of poly(2-oxazoline)s using methyl bromoacetate as initiator followed by direct amidation

Poly(2-alkyl/aryl-2-oxazoline)s (PAOx) are an alluring class of polymers for many applications due to the broad chemical diversity that is accessible for these polymers by simply changing the initiator, terminating agent and the monomer(s) used in their synthesis. Additional functionalities (that are not compatible with the cationic ring-opening polymerization) can be introduced to the polymers via orthogonal post-polymerization modifications. In this work, we expand this chemical diversity and demonstrate an easy and straightforward way to introduce a wide variety of functional end-groups to the PAOx, by making use of methyl bromoacetate (MeBrAc) as a functional initiator. A kinetic study for the polymerization of 2-ethyl-2-oxazoline (EtOx) in acetonitrile (CH3CN) at 140 °C revealed relatively slow initiation and slower polymerization than the commonly used initiator, methyl tosylate (MeOTs). Nonetheless, well-defined polymers could be obtained with MeBrAc as initiator, yielding polymers with near-quantitative methyl ester end-group functionality. Next, the post-polymerization modification of the methyl ester end-group with different amines was explored by introducing a range of functionalities, i.e. hydroxyl, amino, allyl and propargyl end-groups. The lower critical solution temperature (LCST) behavior of the resulting poly(2-ethyl-2-oxazoline)s was found to vary substantially in function of the end-group introduced, whereby the hydroxyl group resulted in a large reduction of the cloud point transition temperature of poly(2-ethyl-2-oxazoline), ascribed to hydrogen bonding with the polymer amide groups. In conclusion, this paper describes an easy and fast modular approach for the preparation of end-group functionalized PAOx.

Alveolar macrophages generate a noncanonical NRF2-driven transcriptional response to Mycobacterium tuberculosis in vivo.

Alveolar macrophages (AMs) are the first cells to be infected during Mycobacterium tuberculosis (M.tb.) infection. Thus, the AM response to infection is the first of many steps leading to initiation of the adaptive immune response required for efficient control of infection. A hallmark of M.tb. infection is the slow initiation of the adaptive response, yet the mechanisms responsible for this are largely unknown. To study the initial AM response to infection, we developed a system to identify, sort, and analyze M.tb.-infected AMs from the lung within the first 10 days of infection. In contrast to what has been previously described using in vitro systems, M.tb.-infected AMs up-regulate a cell-protective antioxidant transcriptional signature that is dependent on the lung environment but not bacterial virulence. Computational approaches including pathway analysis and transcription factor motif enrichment analysis identify NRF2 as a master regulator of the response. Using knockout mouse models, we demonstrate that NRF2 drives expression of the cell-protective signature in AMs and impairs the control of early bacterial growth. AMs up-regulate a substantial pro-inflammatory response to M.tb. infection only 10 days after infection, yet comparisons with bystander AMs from the same infected animals demonstrate that M.tb.-infected AMs generate a less robust inflammatory response than the uninfected cells around them. Our findings demonstrate that the initial macrophage response to M.tb. in the lung is far less inflammatory than has previously been described by in vitro systems and may impede the overall host response to infection.

Integrating Activity with Accessibility in Olefin Metathesis: An Unprecedentedly Reactive Ruthenium-Indenylidene Catalyst.

Access to leading olefin metathesis catalysts, including the Grubbs, Hoveyda, and Grela catalysts, ultimately rests on the nonscaleable transfer of a benzylidene ligand from an unstable, impure aryldiazomethane. The indenylidene ligand can be reliably installed, but to date yields much less reactive catalysts. A fast-initiating, dimeric indenylidene complex (Ru-1) is reported, which reconciles high activity with scaleable synthesis. Each Ru center in Ru-1 is stabilized by a state-of-the-art cyclic alkyl amino carbene (CAAC, C1) and a bridging chloride donor: the lability of the latter elevates the reactivity of Ru-1 to a level previously attainable only with benzylidene derivatives. Evaluation of initiation rate constants reveals that Ru-1 initiates >250× faster than indenylidene catalyst M2 (RuCl2(H2IMes)(PCy3)(Ind)), and 65× faster than UC (RuCl2(C1)2(Ind)). The slow initiation previously regarded as characteristic of indenylidene catalysts is hence due to low ligand lability, not inherently slow cycloaddition at the Ru=CRR' site. In macrocyclization and "ethenolysis" of methyl oleate (i.e., transformation into α-olefins via cross-metathesis with C2H4), Ru-1 is comparable or superior to the corresponding, breakthrough CAAC-benzylidene catalyst. In ethenolysis, Ru-1 is 5× more robust to standard-grade (99.9%) C2H4 than the top-performing catalyst, probably reflecting steric protection at the quaternary CAAC carbon.

The Enhancement of Lump Coal Percentage by High-Pressure Pulsed Hydraulic Fracturing for Sustainable Development of Coal Mines

The enhancement of lump coal percentage (LCP) is of great significance for most aging mines to achieve the production reduction and quality improvement. In order to enhance the LCP of hard coal seam in fully mechanized mining face and prolong the service life of aging mines, this paper puts forward the technological path of LCP enhancement using high-pressure pulsed hydraulic fracturing (HPPHF) based on the detailed analysis of the main factors controlling LCP. By analyzing the correlation between coal fracturing and LCP, the enhancement mechanism of LCP through HPPHF was concluded. Using the extended finite element method, a fluid–solid coupling numerical model of high-pressure pulsed water injection into coal seam was established, and effects of the fracturing method, pulse amplitude, pulse frequency, and water injection pressure on fracturing performance were assessed. Simulation results demonstrate that HPPHF can effectively reduce the required maximum pressure in fracturing, thus providing a higher percentage of coal lumps with lower energy consumption through the repeated pulsed loading of coal masses. Variations in pulsed pressure amplitude and frequency, as well as water injection pressure were positively correlated with fracturing performance. By their effect on the fracturing performance, we found that water injection pressure had the greatest influence, and the pulse amplitude and frequency had similar effects. At the same time, “high amplitude-high frequency” and “high amplitude-low frequency” had characteristics of short initiation time, large initiation pressure, but small fracture width, while “low amplitude-high frequency” and “low amplitude-low frequency” had characteristics of slow initiation speed, low initiation pressure, but large fracture width. Through the field test results in the fully mechanized mining face of Shichangwan Coal Mine, it was found that LCP with a diameter range of 13–100 mm was significantly enhanced by HPPHF. The present study is considered quite instrumental in providing a theoretical foundation for enhancing the LCP of hard coal seams and the sustainable development of coal mine enterprises.

MST1R kinase accelerates pancreatic cancer progression via effects on both epithelial cells and macrophages.

The MST1R (RON) kinase is overexpressed in >80% of human pancreatic cancers, but its role in pancreatic carcinogenesis is unknown. In this study, we examined the relevance of Mst1r kinase to Kras driven pancreatic carcinogenesis using genetically engineered mouse models. In the setting of mutant Kras, Mst1r overexpression increased acinar-ductal metaplasia (ADM), accelerated progression of pancreatic intraepithelial neoplasia (PanIN), and resulted in the accumulation of (mannose receptor C type 1) MRC1+, (arginase 1) Arg+ macrophages in the tumor microenvironment. Conversely, absence of a functional Mst1r kinase slowed PanIN initiation, resulted in smaller tumors, prolonged survival and a reduced tumor associated macrophage content. Mst1r expression was associated with increased production of its ligand Mst1, and in orthotopic models, suppression of Mst1 expression resulted in reduced tumor size, changes in macrophage polarization and enhanced T cell infiltration. This study demonstrates the functional significance of Mst1r during pancreatic cancer initiation and progression. Further, it provides proof of concept that targeting Mst1r can modulate pancreatic cancer growth and the microenvironment. This study provides further rationale for targeting Mst1r as a therapeutic strategy.

The influence of combined gradient structure with residual stress on crack-growth behavior in medium carbon steel

Gradient materials produced by various external surface treatments are widely used in various mechanical structures. In this study, we illustrated how the combined gradient structure and residual stress influences crack-tip plasticity and crack-growth behavior in medium carbon steel S38C. The material used as train axles has a gradient layer of thickness about 8 mm, with fine nanoscale structures in the surface to microstructures of tens of micron in the core. From the surface, the strength in the gradient layer decreases from about 1600 MPa to about 400 MPa, and the corresponding tensile ductility increases from 2% to 13%. Through in-situ fatigue tests, we further revealed slower crack-initiation and faster crack-growth rate in the gradient samples in contrast to their gradient-free coarse-grain counterparts. Using the key material parameters obtained from experiments, we employed finite-element simulations to examine the crack-growth behavior in the gradient structure with compressive residual stress. We showed that both the gradient structure and compressive residual stress reduce the plastic deformation size and hence slow down crack initiation. However, the lower ductility in the high strength gradient layer gives rise to even faster crack growth after the formation of a sharp crack. Based on the definition of the cyclic ΔJ-integral for small scale yielding, we saw lower ΔJ in the presence of the residual stress distribution, hence smaller driving force for the crack-growth rate as the latter monotonically increases with ΔJ.

Living β-selective cyclopolymerization using Ru dithiolate catalysts.

Cyclopolymerization (CP) of 1,6-heptadiyne derivatives is a powerful method for synthesizing conjugated polyenes containing five- or six-membered rings via α- or β-addition, respectively. Fifteen years of studies on CP have revealed that user-friendly Ru-based catalysts promoted only α-addition; however, we recently achieved β-selective regiocontrol to produce polyenes containing six-membered-rings, using a dithiolate-chelated Ru-based catalyst. Unfortunately, slow initiation and relatively low catalyst stability inevitably led to uncontrolled polymerization. Nevertheless, this investigation gave us some clues to how successful living polymerization could be achieved. Herein, we report living β-selective CP by rational engineering of the steric factor on monomer or catalyst structures. As a result, the molecular weight of the conjugated polymers from various monomers could be controlled with narrow dispersities, according to the catalyst loading. A mechanistic investigation by in situ kinetic studies using 1H NMR spectroscopy revealed that with appropriate pyridine additives, imposing a steric demand on either the monomer or the catalyst significantly improved the stability of the propagating carbene as well as the relative rates of initiation over propagation, thereby achieving living polymerization. Furthermore, we successfully prepared diblock and even triblock copolymers with a broad monomer scope.

Molecular-scale thermally activated fractures in methane hydrates: a molecular dynamics study

We perform multiple large molecular dynamics simulations to study the fracture behaviour of monocrystalline methane hydrates under tension. We examine the fracture initiation phase and find that the fracture process can be divided into two phases: slow crack growth and rapid crack propagation. The time of the slow crack growth phase can be predicted by a thermal activation model [L. Vanel et al., J. Phys. D: Appl. Phys., 2009, 42, 214007] where an energy barrier has to be overcome in order for the crack to propagate. Our simulations predict that the slow growth phase vanishes when the stress intensity factor approaches .

Star-Shaped Thermosensitive Poly(2-ethyl-2-oxazines) with the Calixarene Core

Novel star-shaped polymers with the calixarene-type central core and oligo(2-ethyl-2-oxazine) arms are synthesized by cationic polymerization. The kinetic features indicate a slow initiation of polymerization followed by a rapid chain growth. It is demonstrated that the aqueous solutions of the synthesized polymers have a lower critical solution temperature which depends on the core structure. The polymer with the thiacalixarene core is shown to be capable of stabilizing gold nanoparticles.

Floodplain Backwater Effect on Overtopping Induced Fluvial Dike Failure

AbstractFluvial dikes (i.e., levees) can be damaged by overtopping flows, leading to breach formation and severe floods. Accurate prediction of the breach geometry and outflow hydrograph is crucial to achieve sound inundation risk assessment and mitigating measures. A set of laboratory experiments were performed to study overtopping induced fluvial dike breaching. The effects of floodplain tailwater on the breach expansion and outflow were investigated. Results are compared to previous experiments under different main channel inflow discharges combined with a free floodplain. The dike breaching process follows three stages: gradual start of overtopping and slow initiation of dike erosion, fast deepening and widening of the breach with highly transient flows, and flow quasi‐stabilization with or without sustained breach expansion. Using the recorded data, a simplified regression model relating the breach stabilization time and the final breach width to the floodplain confinement and inflow Froude number in the main channel is proposed.

Plasmonic nanoparticle-based epoxy photocuring: A deeper look

Abstract Many epoxy adhesives require high temperatures to bond composite materials. However, oven heating severely restricts what may be attached or enclosed within composite material-based structures and greatly limits the possibilities for repair. Inspired by initial reports of photothermal epoxy curing using plasmonic nanoparticles, we examine how laser-illuminated Au nanoparticles embedded within high-temperature epoxy films convert the conventional thermal curing process into a photothermally driven one. Our theoretical investigations reveal that plasmonic nanoparticle-based epoxy photocuring proceeds through a four-stage process: a rapid, plasmon-induced temperature increase, a slow localized initialization of the curing chemistry that increases the optical absorption of the epoxy film, a subsequent temperature increase as the epoxy absorbs the laser radiation directly, and a final stage that completes the chemical transformation of the epoxy film to its cured state. Our experimental studies validate this model, and also reveal that highly local photocuring can create a stronger bond between composite materials than thermal curing without nanoparticles, at times even stronger than the composite material itself, substantially reducing the time needed for the curing process. Our findings support key advances in our understanding of this approach to the rapid, highly efficient bonding and repair of composite materials.