Nonlocal Treatment Research Articles

Local Treatment and Treatment-Related Adverse Effects Among Patients With Advanced Prostate Cancer

Recent data suggest that local treatment with radical prostatectomy or radiation may improve survival outcomes in men with advanced prostate cancer. However, evidence is lacking on treatment-related adverse effects among men with advanced prostate cancer. To assess the association of local treatment on treatment-related adverse effects among men diagnosed with advanced prostate cancer. This cohort study assessed men diagnosed with advanced prostate cancer (defined as T4, N1, and/or M1 prostate cancer) between January 1, 1999, and December 31, 2013, with follow-up through December 31, 2021, who were treated at Veterans Health Administration medical centers. Local treatment with radical prostatectomy or radiation. Main outcomes were treatment-related adverse effects, including constitutional, gastrointestinal, pain, sexual function, and urinary function conditions, at 3 intervals after initial treatment (≤1 year, >1 to ≤2 years, and >2 to ≤5 years) after initial treatment. This cohort study consisted of 5502 men (mean [SD] age, 68.7 [10.3] years) diagnosed with advanced prostate cancer. Of the cohort, 1705 men (31.0%) received local treatment. There was a high prevalence of adverse conditions in men receiving both local and nonlocal treatment, and these adverse conditions persisted for more than 2 years to 5 years or less after initial treatment. A total of 916 men (75.2%) with initial local treatment and 897 men (67.1%) with initial nonlocal treatment reported the presence of at least 1 adverse condition for more than 2 years to 5 years or less after initial treatment. In the first year, local treatment (vs nonlocal) was associated with adverse gastrointestinal (multivariable-adjusted odds ratio [AOR], 4.08; 95% CI, 3.06-5.45), pain (AOR, 1.57; 95% CI, 1.35-1.83), sexual (AOR, 2.96; 95% CI, 2.42-3.62), and urinary (AOR, 2.25; 95% CI, 1.90-2.66) conditions. Local treatment (without secondary treatment) remained significantly associated with adverse gastrointestinal (AOR, 2.39; 95% CI, 1.52-3.77), sexual (AOR, 3.36; 95% CI, 2.56-4.41), and urinary (AOR, 1.39; 95% CI, 1.09-1.78) conditions at more than 2 years to 5 years or less after treatment. In this cohort study of men with advanced prostate cancer, local treatment was associated with persistent treatment-related adverse effects across multiple domains. These results suggest that patients and clinicians should consider the adverse effects of local treatment when making treatment decisions in the setting of advanced prostate cancer.

Anisotropic Interlayer Force Field for Group-VI Transition Metal Dichalcogenides.

An anisotropic interlayer force field that describes the interlayer interactions in homogeneous and heterogeneous interfaces of group-VI transition metal dichalcogenides (MX2, where M = Mo, W, and X = S, Se) is presented. The force field is benchmarked against density functional theory calculations for bilayer systems within the Heyd-Scuseria-Ernzerhof hybrid density functional approximation, augmented by a nonlocal many-body dispersion treatment of long-range correlation. The parametrization yields good agreement with the reference calculations of binding energy curves and sliding potential energy surfaces. It is found to be transferable to transition metal dichalcogenide (TMD) junctions outside of the training set that contain the same atom types. Calculated bulk moduli agree with most previous dispersion-corrected density functional theory predictions, which underestimate the available experimental values. Calculated phonon spectra of the various junctions under consideration demonstrate the importance of appropriately treating the anisotropic nature of the layered interfaces. Considering our previous parametrization for MoS2, the anisotropic interlayer potential enables accurate and efficient large-scale simulations of the dynamical, tribological, and thermal transport properties of a large set of homogeneous and heterogeneous TMD interfaces.

Intraspecific variation in leaf litter alters fitness metrics and the gut microbiome of consumers.

Biodiversity can have cascading effects throughout ecosystems. While these effects are better understood at coarser taxonomic scales of biodiversity, there has been a resurgence in investigating how biodiversity within species may have cascading effects on communities and ecosystems. We investigate the broader trophic implications of intraspecific variation in the riparian tree, Alnus rubra, where immediately local or 'home' litter decomposes faster than 'away' litter in aquatic and terrestrial systems. With climate change shifting the distributions of plants across the globe, it is essential to understand how shifts in the intraspecific traits of leaf litter may have reverberating effects throughout ecosystems. Here, we find that intraspecific variation in leaf litter has fitness implications for invertebrate consumers, including the algivorous Dicosmoecus and detrivorous Psychoglypha caddisflies, which exhibited increased body size and muscle nitrogen content when incubated within in-situ river mesocosms supplied with local A. rubra litter. Litter source altered caddisfly gut microbiomes by increasing relative abundance of methanogens and methanotrophs among the non-local treatment group. Additionally, Dicosmoecus supplied with non-local litter may have shifted their diet towards a higher proportion of algae, as inferred from shifts in gut microbiome composition and isotopic ratios of muscle tissue. Overall, our study demonstrates that shifting distributions of plant genotypes across the globe may cause plant-microbe mismatches that will disrupt patterns of decomposition and may have consequences on the fitness and foraging behavior of consumers.

A nomogram model for determining optimal patients for local therapy in metastatic prostate cancer: a SEER database-based study

BackgroundNumerous studies have shown that local therapy can improve long-term survival in patients with metastatic prostate cancer. However, it is unclear which patients are the potential beneficiaries.MethodsWe obtained information on prostate cancer patients from the Surveillance, Epidemiology, and End Results database and divided eligible patients into the local treatment group and non-local treatment group. Propensity score matching (PSM) was used to reduce the influence of confounding factors. In the matched local treatment (LT) group, if the median overall survival time (OS) was longer than the Nonlocal treatment (NLT) group, it was defined as a benefit group, otherwise, it was a non-benefit group. Then, univariate and multivariate logistic regression were used to screen out predictors associated with benefits, and a nomogram model was constructed based on these factors. The accuracy and clinical value of the models were assessed through calibration plots and decision curve analysis.ResultsThe study enrolled 7255 eligible patients, and after PSM, each component included 1923 patients. After matching, the median OS was still higher in the LT group than in the NLT group [42 (95% confidence interval: 39–45) months vs 40 (95% confidence interval: 38–42) months, p = 0.03]. The independent predictors associated with benefit were age, PSA, Gleason score, T stage, N stage, and M stage. The nomogram model has high accuracy and clinical application value in both the training set (C-index = 0.725) and the validation set (C-index = 0.664).ConclusionsThe nomogram model we constructed can help clinicians identify patients with potential benefits from LT and formulate a reasonable treatment plan.

480. OUTCOMES OF ADJUVANT LOCAL TREATMENT AFTER ESOPHAGEAL SURGERY WITH POSITIVE RESECTION MARGIN IN INTRATHORACIC ANASTOMOSIS

Abstract Esophageal cancer is aggressive diseases requiring surgery as an essential part of treatment. To achieve increased overall survival, complete resection (R0) is preferred. In some case, however, we encounter positive resection margin (R1). Further resection will be required, but sometimes it is difficult to do additional procedure because of various reasons, especially the highest location of anastomosis. Hypothesis of study is that R1 resection with adjuvant local therapy shows comparable result with R0 resection in intrathoracic anastomosis From 2000 to 2017, total 2723 patients received the esophagectomy and mediastinal lymph node dissection for esophageal cancer. R0 resection was 1701, and R1 resection was 76 patients. Patients who received distal esophagectomy (n=56) and lack of information about adjuvant therapy (n=24) were excluded Because of differences in some variables, we conducted 2:1 propensity score matching to reduce differences between groups. Comparison of R1 resection group with adjuvant local therapy to R0 resection group is conducted Overall survival (OS) and recurrence free survival (RFS) were estimated with Kaplan-Meier method. 76 patients were identified with R1 resection. Of those patients, 30 patients showed positive proximal resection margin from frozen section during surgery. When compared to R0 resection group (including patients with adjuvant treatment), OS and RFS were statistically lower in R1 resection group (p=0.03 and 0.023, respectively) When comparing R1 with adjuvant local treatment group to R0 resection group, there were no statistical differences in both OS and RFS.(p=0.13 and 0.22, respectively) In R1 resection group, adjuvant local treatment group show favorable result compared to non-local treatment group, but there were no statistical differences in OS and RFS.(p=0.26 and 0.17, respectively) R1 resection with proper adjuvant local treatment enable us to achieve comparable result with R0 resection group in intrathoracic anastomosis When anastomosis is made at the highest level of thorax (i.e. thoracic inlet level), it is not easy to perform additional intrathoracic resection. If it is difficult to do further resection when resection margin is positive, adjuvant local treatment after surgery can be one reasonable option to improve patient’s survival or minimize disease recurrence

Cytoreductive radical prostatectomy or radiation therapy for metastases prostate cancer: Evidence from meta-analysis.

Background:Cytoreductive radical prostatectomy (RP), transurethral resection of the prostate, and radiation therapy were the main local treatments for oligometastatic prostate cancer (PCa). An optimal local treatment for metastases PCa was not consensus. The purpose of this study was to evaluate the effect on these local treatments for patients with metastases PCa.Methods:All relevant studies were systematically searched through PubMed, Web of Science through November 1, 2021. Studies were screened by inclusion and exclusion criteria. Progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS) were evaluated by this meta-analysis.Results:Eleven studies were identified that met the inclusion criteria. 644 patients received cytoreductive surgery, 8556 patients received no surgery or radiation therapy (RT), and 461 patients received RP + androgen deprivation therapy compared with 746 patients who received RT. Pooled data indicated that cytoreductive surgery significantly prolonged the PFS (OR = 0.65, 95% CI 0.53–0.80, P < .0001), CSS and OS (OR = 0.49, 95% CI 0.43–0.56, P < .00001; and OR = 0.80, 95% CI 0.72–0.88, P < .00001; respectively). Comparing cytoreductive surgery with RT, CSS, and OS were similar (OR = 0.82, 95% CI 0.67–1.01, P = .06; and OR = 0.93, 95% CI 0.79–1.09, P = .39; respectively).Conclusions:Cytoreductive radical prostatectomy significantly prolonged the PFS for metastatic PCa. Although OS was considered a-not-so significant difference between cytoreductive surgery and non-local therapy, non-local treatment was not recommended.

Born-Oppenheimer molecular dynamics and electronic properties of liquid H2S: The importance of a non-local approach to dispersion interactions

The dynamics and electronic properties of liquid H2S were investigated by Born–Oppenheimer molecular dynamics (BOMD). The Vydrov and Van Voorhis VV10 exchange–correlation functional [J. Chem. Phys. 133 (2010) 244103] that includes non-local correlation was adopted for generating the dynamics. This functional predicts the binding energy of the (H2S)2 dimer in very good agreement with experiment. Emphasis was placed on the structure, polarisation effects, and electronic absorption in liquid phase. The dipole moment in liquid H2S increases by 0.2D relative to the gas phase. A very small change (∼0.1 eV) in the position of the first maximum of the electronic absorption spectrum is observed when we compare liquid H2S and the isolated molecule. This is in contrast to liquid water where a [0.4-0.7] eV blue shift in the first peak of the absorption spectrum relative to the gas phase is observed. Exciton binding energies of H2S are calculated and compared with results for water. Their importance for explaining the difference between the blue-shift in H2S and water is discussed. The results indicate that although the (H2S)2 dimer is HB, some specific features characterising the structure and electronic properties of other HB liquids are not observed in liquid H2S. The interest of a non-local treatment of van der Waals interactions in liquid H2S is stressed.

Nonlocal thermal effects on biological tissues and tumors

• Analysis of heat distribution of tumor growth based on nonlocal rang effects. • The long-range kernel approach generalizes the Pennes bioheat equation. • Temperature is affected by nonlocal effects and by the localization of the neighbouring tumors. • The nonlocal kernel approach may imitate what is going on biologically within a tumor where cancer cells reside. Tumors consist of heterogeneous populations of cells. The cell–cell interactions processes play a critical role in cancer invasion and could be influenced by the mutation of cancerous tumor. This study is devoted to the analysis of the temperature distribution of tumor growth based on nonlocal range effects mainly the tumor-tumor influence incorporated in a kernel. The long-range kernel approach generalizes the Pennes bioheat equation which is the most commonly used formulation of heat transfer in biological systems. It was observed that the temperature is affected by nonlocal effects and by the localization of the neighbouring tumors. The nonlocal kernel approach may imitate what is going on biologically within a tumor where cancer cells reside. This may assist to the nonlocal treatment of cancer invasion in a human body.

Adverse upgrading and/or upstaging in contemporary low-risk prostate cancer patients

BackgroundUpgrading and/or upstaging in low-risk prostate cancer (PCa) patients may represent an indication for active treatment instead of active surveillance (AS). We addressed contemporary upgrading and/or upstaging rates in a large population based-cohort of low-risk PCa patients.Materials and methodsWhitin the SEER database (2010–2015), NCCN low-risk PCa patients were identified across management modalities: radical prostatectomy (RP), radiotherapy (RT) and non-local treatment (NLT). In RP patients, upgrading and/or upstaging rates were assessed in logistic regression models.ResultsOverall, of 27,901 low-risk PCa patients, 38% underwent RP vs 28% RT vs 34% NLT. RP patients were the youngest and harbored the highest percentage of positive cores and a higher rate of cT2a than NLT. At RP, 46.2% were upgraded to GGG ≥ 2, 6.0% to GGG ≥ 3 and 10.5% harbored nonorgan-confined stage (NOC, pT3-4 or pN1). Of NOC patients, 1.6% harbored GGG ≥ 3, 6.3% harbored GGG2 and 2.6% harbored GGG1. Of pT2 patients, 4.4% harbored GGG ≥ 3, 33.9% harbored GGG2 and 51.3% harbored GGG1. Age, PSA, percentage of positive cores and number of positive cores independently predicted the presence of NOC and/or GGG ≥ 3, but with low accuracy (63.9%).ConclusionsIn low-risk PCa, critical changes between tumor grade and stage at biopsy vs RP may be expected in very few patients: NOC with GGG ≥ 3 in 1.6% and NOC with GGG2 in 6.3%. Other patients with upgrading and/or upstaging combinations will invariably harbor either pT2 or GGG1 that far less critically affect PCa prognosis.

Endemic Lineages of Batrachochytrium dendrobatidis Are Associated With Reduced Chytridiomycosis-Induced Mortality in Amphibians: Evidence From a Meta-Analysis of Experimental Infection Studies.

Emerging infectious wildlife diseases have caused devastating declines, particularly when pathogens have been introduced in naïve host populations. The outcome of disease emergence in any host population will be dictated by a series of factors including pathogen virulence, host susceptibility, and prior opportunity for coevolution between hosts and pathogens. Historical coevolution can lead to increased resistance in hosts and/or reduced virulence in endemic pathogens that allows stable persistence of host and pathogen populations. Adaptive coevolution may also occur on relatively short time scales following introduction of a novel pathogen. Here, we performed a meta-analysis of multi-strain Batrachochytrium dendrobatidis (Bd) infection experiments to test whether: (1) amphibian hosts exhibit lower mortality rates when infected with strains belonging to endemic Bd lineages relative to the Global Panzootic Lineage (Bd-GPL), hypothetically owing to long co-evolutionary histories between endemic Bd lineages and their amphibian hosts; and (2) amphibians exhibit lower mortality rates when infected with local Bd-GPL strains compared with non-local Bd-GPL strains, hypothetically owing to recent selection for tolerance or resistance to local Bd-GPL strains. We found that in a majority of cases, amphibians in endemic Bd treatments experienced reduced mortality relative to those in Bd-GPL treatments. Hosts presumed to have historically coexisted with endemic Bd did not show reduced mortality to Bd-GPL compared with hosts that have not historically coexisted with endemic Bd. Finally, we detected no overall difference in amphibian mortality between local and non-local Bd-GPL treatments. Taken together, our results suggest that long-term historical coexistence is associated with less disease-induced mortality potentially due to hypovirulence in endemic Bd lineages, and that more recent coexistence between amphibians and Bd-GPL has not yet resulted in reduced host susceptibility or pathogen virulence. This corroborates previous findings that Bd-GPL introduced via the global amphibian trade has a high capacity for causing disease-induced mortality.

Selective salvage radiotherapy could provide favorable outcomes in patients with refractory or relapsed primary central nervous system lymphoma.

To date, there is no relevant data supporting the role of salvage radiotherapy (sRT) in patients with refractory or relapsed primary central nervous system lymphoma (PCNSL). Herein, we aimed to investigate the impact of sRT in patients with refractory or relapsed PCNSL following upfront HD-MTX. We retrospectively reviewed 89 patients who had refractory (n = 16) or recurrent disease after an initial favorable response (n = 73); among them, 41 were treated with sRT and 48 were treated without sRT (nRT). Event-free survival (rEFS) and overall survival (rOS) after first recurrence were considered from the date of recurrence to date of each event. Overall, the first failure was diagnosed at a median of 11.0months [interquartile range (IQR), 5.6-26.4] after first treatment. More than half of the patients had recurrent disease involving initial tumor bed (n = 47), deep structure (n = 67), and multiple lesions (n = 58). Among 19 patients who were initially treated with 23.4Gy of whole brain RT, 10 patients received sRT as a re-irradiation; other 31 patients in sRT group were RT naïve patients. There was no significant difference in tumor characteristics between sRT and nRT group. Overall and complete response after salvage treatment were 80% and 48%, respectively; sRT provided higher overall response rate than nRT (93% vs. 69%, p = 0.011). With a median follow-up of 14.3months (IQR, 7.9-31.4), 2-year rEFS and rOS rates were 27% and 57%, respectively. There were no differences in rEFS and rOS according to sRT (sRT vs. nRT, 26% vs. 28%, p = 0.730; 63% vs. 50%, p = 0.690). Poor performance, recurrence interval < 8months, and unfavorable response following salvage treatment were associated with inferior rEFS and rOS. Additionally, sRT and stem cell transplantation improved response rate independently after multivariate analysis for complete/partial response. We found favorable response rate and comparable survival outcomes following sRT compared with non-local treatments for patients with refractory/relapsed PCNSL. Further studies of patient selection could stratify patients who can benefit from sRT.

Anisotropic Interlayer Force Field for Transition Metal Dichalcogenides: The Case of Molybdenum Disulfide.

An anisotropic interlayer force field that describes the interlayer interactions in molybdenum disulfide (MoS2) is presented. The force field is benchmarked against density functional theory calculations for both bilayer and bulk systems within the Heyd–Scuseria–Ernzerhof hybrid density functional approximation, augmented by a nonlocal many-body dispersion treatment of long-range correlation. The parametrization yields good agreement with the reference calculations of binding energy curves and sliding potential energy surfaces for both bilayer and bulk configurations. Benchmark calculations for the phonon spectra of bulk MoS2 provide good agreement with experimental data, and the calculated bulk modulus falls in the lower part of experimentally measured values. This indicates the accuracy of the interlayer force field near equilibrium. Under external pressures up to 20 GPa, the developed force field provides a good description of compression curves. At higher pressures, deviations from experimental data grow, signifying the validity range of the developed force field.

Anisotropic failure behaviour and breakdown pressure interpretation of hydraulic fracturing experiments on shale

Shales with a laminated structure typically exhibit inherent anisotropy and strong brittleness, resulting in complex failure patterns and fracture evolution during hydraulic fracturing. To investigate the fracturing mechanism and layer effect of Longmaxi shale from southwest China, a novel testing setup with a high-efficiency sealing method was developed for laboratory hydraulic fracturing, based on which a series of fracturing tests was conducted on shale samples under different confining pressures. The anisotropic mechanical behaviour due to the shale lamination effect was considered by drilling samples at seven different inclinations with reference to the bedding plane. The results showed apparent brittle failure characteristics and anisotropic phenomena both in strength and failure patterns. Three main failure patterns can be identified as split, split-bending and slip along the bedding plane. The corresponding fracture roughness was further analyzed by laser scanning, which shows that the slip mode with shale layer activation can provide a relatively smooth channel. Of particular interest is that anomalously high breakdown pressure, which fluctuates in the samples at different layer orientations and cannot be explained by conventional models, was also observed in our fracturing tests. Inspired by the nonlocal treatment of line stress criterion, an average tensile stress-based model by introducing an equivalent characteristic length was then proposed for interpreting such unusual breakdown pressures, and the inherent mechanism behind hydraulic fracturing was discussed. Comparison analysis showed that the proposed criterion not only predicts the testing data quite well, but can also be degenerated to conventional models in specific cases. The knowledge achieved in this study may provide practical implications for perforation design and breakdown pressure evaluation in field hydraulic fracturing operations.

Nomogram predicting survival to assist decision-making of radical prostatectomy in patients with metastatic prostate cancer

BackgroundRadical prostatectomy (RP) has heterogeneous effects on survival of patients with metastatic prostate cancer (mPCa). A reliable model to predict risk of cancer-specific mortality (CSM) and the potential benefit derived from RP is needed.MethodsPatients diagnosed with mPCa were identified using the Surveillance, Epidemiology, and End Results database (2004–2015) and categorized in RP versus nonlocal treatment (NLT). Based on the Fine and Gray competing risks model in 8,463 NLT patients, a nomogram was created to predict CSM in mPCa patients. Decision tree analysis was then utilized for patient stratification. The effect of RP was evaluated among 3 different subgroups.ResultsA total of 8,863 patients were identified for analysis. Four hundred (4.5%) patients received RP. The 5-year cumulative incidence of CSM was 52.4% for the entire patients. Based on nomogram scores, patients were sorted into three risk groups using decision tree analysis. In the low- and intermediate-risk group, RP was found to be significantly correlated with a 21.7% risk reduction of 5-year CSM, and 25.0% risk reduction of 5-year CSM, respectively, whereas RP was not associated with CSM in high-risk group (hazard ratio =0.748, 95% confidence interval 0.485–1.150; P=0.190).ConclusionsWe developed a novel nomogram and corresponding patient stratification predicting CSM in mPCa patients. A newly identified patient subgroup with low-, and intermediate-risk of CSM might benefit more from RP. These results should be further validated and improved by ongoing prospective trials.

Topological population analysis and pairing/unpairing electron distribution evolution: Atomic B3+ cluster bending mode, a case study

Local and non-local topological treatment of electronic distributions are applied to a simple out of equilibrium case of an electron-deficient three-atom cluster, B3+. The bending movement is described in detail through the onset and disappearance of critical points defining two kinds of molecular structures, characterizing a transition state (TS) and predicting two stable equilibrium geometries. All points in this rich evolution and the structural change in the out of equilibrium conformations has been featured and distinguished by the behavior of the population magnitudes and of the paired and unpaired electron densities within the non-local and local points of view of the topological formalism. The unpaired or electron hole density appears as relevant in both versions, the non-local or integrated one, in which it is sometimes called free-valence and also for its complementary counterpart, the local one, to describe and to quantify the interatomic interactions. The stability of the cluster B3+ is characterized in terms of a topologically defined ring structure and the highest total two- and three-center populations, thus showing the role of the geometry, the covalence, and the complex patterns. Consideration of the electron correlation effects constitutes the basement of the results gathered, thus displaying their influence in the formation and breaking of boron bonding interactions.

Confinement in Nanodiscs Anisotropically Modifies Lipid Bilayer Elastic Properties.

Lipid nanodiscs are small synthetic lipid bilayer structures that are stabilized in solution by special circumscribing (or scaffolding) proteins or polymers. Because they create native-like environments for transmembrane proteins, lipid nanodiscs have become a powerful tool for structural determination of this class of systems when combined with cryo-electron microscopy or nuclear magnetic resonance. The elastic properties of lipid bilayers determine how the lipid environment responds to membrane protein perturbations, and how the lipid in turn modifies the conformational state of the embedded protein. However, despite the abundant use of nanodiscs in determining membrane protein structure, the elastic material properties of even pure lipid nanodiscs (i.e., without embedded proteins) have not yet been quantitatively investigated. A major hurdle is due to the inherently nonlocal treatment of the elastic properties of lipid systems implemented by most existing methods, both experimental and computational. In addition, these methods are best suited for very large “infinite” size lipidic assemblies, or ones that contain periodicity, in the case of simulations. We have previously described a computational analysis of molecular dynamics simulations designed to overcome these limitations, so it allows quantification of the bending rigidity (KC) and tilt modulus (κt) on a local scale even for finite, nonperiodic systems, such as lipid nanodiscs. Here we use this computational approach to extract values of KC and κt for a set of lipid nanodisc systems that vary in size and lipid composition. We find that the material properties of lipid nanodiscs are different from those of infinite bilayers of corresponding lipid composition, highlighting the effect of nanodisc confinement. Nanodiscs tend to show higher stiffness than their corresponding macroscopic bilayers, and moreover, their material properties vary spatially within them. For small-size MSP1 nanodiscs, the stiffness decreases radially, from a value that is larger in their center than the moduli of the corresponding bilayers by a factor of ∼2–3. The larger nanodiscs (MSP1E3D1 and MSP2N2) show milder spatial changes of moduli that are composition dependent and can be maximal in the center or at some distance from it. These trends in moduli correlate with spatially varying structural properties, including the area per lipid and the nanodisc thickness. Finally, as has previously been reported, nanodiscs tend to show deformations from perfectly flat circular geometries to varying degrees, depending on size and lipid composition. The modulations of lipid elastic properties that we find should be carefully considered when making structural and functional inferences concerning embedded proteins.

A generalized Stefan model accounting for system memory and non-locality

The Stefan problem, involving the tracking of an evolving phase-change front, is the prototypical example of a moving boundary problem. In basic one-dimensional problems it is well known that the front advances as the square root of time. When memory or non-locality are introduced into the system, however, this classic signal may be anomalous; replaced by a power-law advance with a time exponent that differs from n = 1/2. Up to now memory treatments in Stefan problem models have only been able to reproduce sub-diffusive front movements with exponents n < 1/2 and non-local treatments have only been able to reproduce super-diffusive behavior n > 1/2. In the present paper, by using a generalized Caputo fractional derivative operator, we introduce new memory and non-local treatment for Stefan problems. On considering a limit case Stefan problem, related to the melting problem, we are able to show that, this general treatment can not only produce arbitrary power-law in time predictions for the front movement but, in the case of memory treatments, can also produce non-power-law anomalous behaviors. Further, also in the context of the limit problem, we are able to establish an equivalence between non-locality and a space varying conductivity and memory and a time varying conductivity.

Nonlocal treatment of resonant vibrational excitation in electron-dioxygen collision

SynopsisThe cross sections for vibrational excitations of O2 through collisions with electron are calculated using the nonlocal discrete-state-in-continuum model and its local approximation and compared to experimental results.

Mesoscopic investigation of size effect in notched concrete beams: The role of fracture process zone

A comprehensive mesoscopic investigation has been conducted into the classic topic of size effect, using notched plain concrete beams subjected to three-point bending as a test bed. The concrete beams are modelled as random heterogeneous material containing three components, coarse aggregates, mortar and the interface transition zone. Mesoscopic numerical simulations using a 2D mesoscale continuum damage-based model, enhanced by a nonlocal treatment, is used to capture the whole fracture process in concrete materials. Both global and local numerical results are then examined and verified with relevant experimental evidence from the literature. A stress field interaction theory based on the strip yield model is proposed to interpret the size effect phenomenon and the role of detailed fracture process zone features is discussed accordingly.

A mesh objective continuum damage model for quasi-brittle crack modelling and finite element implementation

In the framework of continuum damage mechanics, a computational model for quasi-brittle crack modelling is proposed. The proposed model has significant mesh-objectivity and accuracy advantages over existing methods for modeling quasi-brittle crack. These stem from the combination of the local crack tracking algorithm, the new calculation of crack bandwidth and the non-local treatment regarding strain field. Resorting to the implementation of local crack tracking algorithm, it is desirable that the spurious dependence of conventional continuum damage mechanics-based model on mesh bias can be effectively addressed. The new estimation of the real-time crack bandwidth can be not only depending on the element size and pattern, but also on the physical crack path within each consolidate cracked element. Thus, the energy dissipation during crack propagation can be characterized in a more accurate, physically based manner. The non-local averaging regarding the strain field in the course of failure evolution is carried out within an elliptical domain, the configuration of which is related to finite element and crack trajectory obtained by the local crack track algorithm. With this combined technique, it is expected that a more accurate crack evolution course can be achieved numerically, which allows engineers to adopt relatively coarse unstructured discretizations without sacrificing solution accuracy. By numerical examples, the proposed model, empowered by the combined techniques, demonstrates significant improvements in the prediction of crack propagating of quasi-brittle materials. This model may provide engineers a more reliable tool in practical application of computational material failure.