Excluded Volume Research Articles

The NANOGrav 15 yr Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries

Evidence for a low-frequency stochastic gravitational-wave background has recently been reported based on analyses of pulsar timing array data. The most likely source of such a background is a population of supermassive black hole binaries, the loudest of which may be individually detected in these data sets. Here we present the search for individual supermassive black hole binaries in the NANOGrav 15 yr data set. We introduce several new techniques, which enhance the efficiency and modeling accuracy of the analysis. The search uncovered weak evidence for two candidate signals, one with a gravitational-wave frequency of ∼4 nHz, and another at ∼170 nHz. The significance of the low-frequency candidate was greatly diminished when Hellings–Downs correlations were included in the background model. The high-frequency candidate was discounted due to the lack of a plausible host galaxy, the unlikely astrophysical prior odds of finding such a source, and since most of its support comes from a single pulsar with a commensurate binary period. Finding no compelling evidence for signals from individual binary systems, we place upper limits on the strain amplitude of gravitational waves emitted by such systems. At our most sensitive frequency of 6 nHz, we place a sky-averaged 95% upper limit of 8 × 10−15 on the strain amplitude. We also calculate an exclusion volume and a corresponding effective radius, within which we can rule out the presence of black hole binaries emitting at a given frequency.

Effective dynamics and fluctuations of a trapped probe moving in a fluid of active hard discs (a)

We study the dynamics of a single trapped probe surrounded by self-propelled active particles in two dimensions. In the limit of large size separation, we perform an adiabatic elimination of the small active particles to obtain an effective Markovian dynamics of the large probe, yielding explicit expressions for the mobility and diffusion coefficient. To calculate these expressions, we perform computer simulations employing active Brownian discs and consider two scenarios: non-interacting bath particles and purely repulsive interactions modeling volume exclusion. We keep the probe-to-bath size ratio fixed and vary the propulsion speed of the bath particles. The positional fluctuations of a trapped probe are accessible in experiments, for which we test the prediction from the adiabatic elimination. We find that for a passive bath the Markovian prediction that the integrated force correlations equal the drag coefficient is not fulfilled in the simulations. However, this discrepancy is small compared to the active contribution and the overall agreement between predicted and measured probe fluctuations is very good at larger speeds.

Chain rotational dynamics in dilute polymer solutions and melts under shear flow

We present detailed scaling characteristics of the chain rotation dynamics in shear flow for melt and dilute linear polymer systems using extensive atomistic and coarse-grained Brownian dynamics (BD) molecular dynamics simulations, respectively. We find that the dilute systems with hydrodynamic interaction (HI) and excluded volume (EV) effects generally exhibit two distinct scaling behavior of the chain rotation time τrot between the intermediate and strong flow regimes, whereas the free-draining dilute polymer systems display a relatively simple single-scaling behavior for τrot with respect to the shear rate throughout the intermediate-to-strong flow regimes. This dynamic feature correlates with the scaling characteristics of average chain deformation and orientation of the system with respect to the flow strength. Notably, the combined HI and EV effects generally weaken the structural change of polymer chains in response to the applied flow and enhance the overall chain rotation dynamics by disturbing the chain stretch and alignment to the flow direction. Accordingly, due to the variation in the HI and EV effects (in association with chain deformation) with the flow strength, the dilute systems with HI and EV turn out to reveal relatively lower and higher scaling behaviors of τrot in the intermediate and strong flow regimes, respectively, in comparison to the corresponding free-draining systems. Despite the absence of HI and EV effects, the melt systems also exhibit two distinct scaling behaviors of τrot between the intermediate and strong flow regimes. This feature arises from the intermolecular interactions between chains, resulting in a significant influence of interchain entanglement and interchain dynamic collision on the chain rotation dynamics. It is further observed that the overall τrot scaling behavior for each system is predominantly determined by the corresponding scaling behavior of the kinematically stable (diffusive) angular regions near the flow direction, where the flow force is relatively weak. Additionally, polymer chains in kinematically unstable (convective) angular regions exhibit nearly affine chain rotation dynamics conforming to the imposed flow field, independent of the polymer concentration and chain length. This is considered to be a universal feature for general polymeric liquids in shear flow.

Numerical analysis of a finite volume scheme for charge transport in perovskite solar cells

Abstract In this paper, we consider a drift-diffusion charge transport model for perovskite solar cells, where electrons and holes may diffuse linearly (Boltzmann approximation) or nonlinearly (e.g., due to Fermi–Dirac statistics). To incorporate volume exclusion effects, we rely on the Fermi–Dirac integral of order $-1$ when modeling moving anionic vacancies within the perovskite layer, which is sandwiched between electron and hole transport layers. After nondimensionalization, we first prove a continuous entropy-dissipation inequality for the model. Then, we formulate a corresponding two-point flux finite volume scheme on Voronoi meshes and show an analogous discrete entropy-dissipation inequality. This inequality helps us to show the existence of a discrete solution of the nonlinear discrete system with the help of a corollary of Brouwer’s fixed point theorem and the minimization of a convex functional. Finally, we verify our theoretically proven properties numerically, simulate a realistic device setup and show exponential decay in time with respect to the $L^2$ error as well as a physically and analytically meaningful relative entropy.

Improved Yield and Electrical Properties of Poly(Lactic Acid)/Carbon Nanotube Composites by Shear and Anneal.

Shear and thermal processing can greatly influence nanoparticles' orientation and dispersion, affecting the nanocomposites' conductivity and mechanical properties. The synergistic effects of shear flow and Carbon nanotubes (CNTs) nucleating ability on the crystallization mechanisms have been proven. In this study, Polylactic acid/Carbon nanotubes (PLA/CNTs) nanocomposites were produced by three different molding methods: compression molding (CM), conventional injection molding (IM), and interval injection molding (IntM). Solid annealing at 80 °C for 4 h and pre-melt annealing at 120 °C for 3 h was applied to research the CNTs' nucleation effect and the crystallized volume exclusion effect on the electrical conductivity and mechanical properties. The volume exclusion effect only significantly impacts the oriented CNTs, causing the conductivity along the transverse direction to rise by about seven orders of magnitude. In addition, the tensile modulus of the nanocomposites decreases with the increased crystallinity, while the tensile strength and modulus decrease.

Universality in conformations and transverse fluctuations of a semi-flexible polymer in a crowded environment.

We study the universal aspects of polymer conformations and transverse fluctuations for a single swollen chain characterized by a contour length L and a persistence length ℓp in two dimensions (2D) and three dimensions (3D) in the bulk, as well as in the presence of excluded volume (EV) particles of different sizes occupying different area/volume fractions. In the absence of the EV particles, we extend the previously established universal scaling relations in 2D [Huang et al., J. Chem. 140, 214902 (2014)] to include 3D and demonstrate that the scaled end-to-end distance ⟨RN2⟩/(2Lℓp) and the scaled transverse fluctuation ⟨l⊥2⟩/L as a function of L/ℓp collapse onto the same master curve, where ⟨RN2⟩ and ⟨l⊥2⟩ are the mean-square end-to-end distance and transverse fluctuations. However, unlike in 2D, where the Gaussian regime is absent due to the extreme dominance of the EV interaction, we find that the Gaussian regime is present, albeit very narrow in 3D. The scaled transverse fluctuation in the limit L/ℓp ≪ 1 is independent of the physical dimension and scales as ⟨l⊥2⟩/L∼(L/ℓp)ζ-1, where ζ = 1.5 is the roughening exponent. For L/ℓp ≫ 1, the scaled fluctuation scales as ⟨l⊥2⟩/L∼(L/ℓp)ν-1, where ν is the Flory exponent for the corresponding spatial dimension (ν2D = 0.75 and ν3D = 0.58). When EV particles of different sizes for different area or volume fractions are added into 2D and 3D systems, our results indicate that the crowding density either does not or does only weakly affect the universal scaling relations. We discuss the implications of these results in living matter by showing the experimental result for a dsDNA on the master plot.

Rotating cluster formations emerge in an ensemble of active particles

Rotating clusters or vortices are formations of agents that rotate around a common center. These patterns may be found in very different contexts: from swirling fish to surveillance drones. Here, we propose a minimal model for self-propelled chiral particles with inertia, which shows different types of vortices. We consider an attractive interaction for short distances on top of the repulsive interaction that accounts for volume exclusion. We study cluster formation and we find that the cluster size and clustering coefficient increase with the packing of particles. Finally, we classify three new types of vortices: encapsulated, periodic and chaotic. These clusters may coexist and their proportion depends on the density of the ensemble. The results may be interesting to understand some patterns found in nature and to design agents that automatically arrange themselves in a desired formation while exchanging only relative information.

Entropic contribution of ACE2 glycans to RBD binding

The spike protein of the SARS-CoV-2 virus (the causative agent of COVID-19) recognizes the host cell by binding to the peptidase domain (PD) of the extracellular receptor angiotensin-converting enzyme 2 (ACE2). A variety of carbohydrates could be attached to the six asparagines in the PD, resulting in a heterogeneous population of ACE2 glycoforms. Experiments have shown that the binding affinity of glycosylated and deglycosylated ACE2 to the virus is virtually identical. In most cases, the reduction in glycan size correlates with stronger binding, which suggests that volume exclusion, and hence entropic forces, determine the binding affinity. Here, we quantitatively test the entropy-based hypothesis by developing a lattice model for the complex between ACE2 and the SARS-CoV-2 spike protein receptor-binding domain (RBD). Glycans are treated as branched polymers with only volume exclusion, which we justify using all-atom molecular dynamics simulations in explicit water. We show that the experimentally measured changes in the ACE2-RBD dissociation constants for a variety of engineered ACE2 glycoforms are in reasonable agreement with our theory, thus supporting our hypothesis. However, a quantitative recovery of all the experimental data could require weak attractive interactions.

Non-equilibrium flow of van der Waals fluids in nano-channels

The Enskog–Vlasov equation provides a consistent description of the microscopic molecular interactions for real fluids based on the kinetic and mean-field theories. The fluid flows in nano-channels are investigated by the Bhatnagar–Gross–Krook (BGK) type Enskog–Vlasov model, which simplifies the complicated Enskog–Vlasov collision operator and enables large-scale engineering design simulations. The density distributions of real fluids are found to exhibit inhomogeneities across the nano-channel, particularly at large densities, as a direct consequence of the inhomogeneous force distributions caused by the real fluid effects including the fluid molecules' volume exclusion and the long-range molecular attraction. In contrast to the Navier–Stokes equation with the slip boundary condition, which fails to describe nano-scale flows due to the coexistence of confinement, non-equilibrium, and real fluid effects, the Enskog–Vlasov–BGK model is found to capture these effects accurately as confirmed by the corresponding molecular dynamics simulations for low and moderate fluid densities.

Polyethylene glycol induced structural modulation of holo alpha-lactalbumin: In vitro and in vivo approach towards protein stability

Macromolecular crowding is driven by hard-core repulsions and soft interactions, may have both the stabilizing and destabilizing effects on protein folding and stability, which has gradually gained attention in recent years. Here, we investigated the impact of polyethylene glycol (PEG), a polymer of ethylene glycol and a constituent of many drugs and eye drops on the structure and stability of holo alpha-lactalbumin (α -LA). Results showed that there was a substantial alteration in the secondary structure of holo α -LA. Further, it was found that PEG disrupted the tertiary structure. In holo α -LA, PEG has been found to create a molten globule state, where the intermediate state contains hydrophobic patches and has a greater hydrodynamic volume than the native protein. Additionally, at the physiological pH, isothermal titration calorimetry revealed a significant binding between holo α -LA and PEG 20,000 Da. We observed that while researching macromolecular crowding, it is extremely important to consider protein binding with crowder and other soft interactions carefully. In this scenario, destabilizing protein-crowder interactions dominated the stabilizing exclusion volume effect.

Continuous precipitation of antibodies using oscillatory flow reactor: A proof of concept

Antibodies are among the most important drugs in the pharmaceutical industry. Their increasing demand has pressured the industry to increase upstream antibody titers, making downstream processing the new manufacturing bottleneck. Precipitation is an attractive alternative to current purification platforms by reducing costs, increasing yields and decreasing the scale-up process complexity. In the present work, continuous precipitation of antibodies using an oscillatory flow reactor (OFR) was explored. The combination of cross-linking (zinc chloride, ZnCl2) and volume exclusion (polyethylene glycol, PEG) agents was examined for precipitation of antibodies from an artificial IgG and FBS mixture, mimicking the supernatant of antibody-producing cells. The PEG/ZnCl2 ratio was first optimized in batch and further implemented in the OFR under continuous operation, where the influence of mixing intensity (frequency, amplitude and flow rate) was investigated. Continuous precipitation carried out in the OFR with 14% PEG6000 and 4 mM ZnCl2 enabled the recovery of over 99% of antibodies with 90% purity, demonstrating the implementation viability of this operation for the initial capture of antibodies. It must be also highlighted that precipitation did not affect the secondary structure of the antibody according to circular dichroism measurements.

Nonspecific interaction and overlap concentration influence macromolecular crowding effect on glucose oxidase activity

Macromolecular crowding can change kinetics of enzyme catalysis. How interaction between enzymes and neighboring macromolecules contributes to the crowding effect on enzyme catalysis has not been quantitatively revealed. In this study, crowding effects of dextran and poly(ethylene glycol) (PEG) on glucose oxidase (GOx) are studied. Fluorescence resonance energy transfer experiments show the high transfer efficiency and stable interaction between the dextran and GOx. Further fluorescence quenching analysis also proves that the association of the dextran-GOx pair can become stronger than that of the PEG-GOx pair. Dextrans with concentrations above or below their chain overlap concentrations (c*) reduce Michaelis constants (Km) of GOx catalysis by 90 % or 45 %, respectively, through volume exclusion mechanism, and in the meantime elevate the enzymatic efficiency (kcat/Km) by 8-fold or by 3-fold, respectively, which is more dramatic than that found in other enzymes before. Strong association between the enzyme and the dextran results in slow turnover rates (kcat). Intermediate crowding with weak to moderate affinity to the enzyme below the c* can tune the kcat higher than in the free state. Catalysis under crowded conditions is a joint effect of the enzyme-crowder nonspecific interaction, volume exclusion and overlap condition of the crowders.

Cardiac MRI: An Alternative Method to Determine the Left Ventricular Function.

(1) Background: With the conventional contour surface method (KfM) for the evaluation of cardiac function parameters, the papillary muscle is considered to be part of the left ventricular volume. This systematic error can be avoided with a relatively easy-to-implement pixel-based evaluation method (PbM). The objective of this thesis is to compare the KfM and the PbM with regard to their difference due to papillary muscle volume exclusion. (2) Material and Methods: In the retrospective study, 191 cardiac-MR image data sets (126 male, 65 female; median age 51 years; age distribution 20-75 years) were analysed. The left ventricular function parameters: end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined using classical KfW (syngo.via and cvi42 = gold standard) and PbM. Papillary muscle volume was calculated and segmented automatically via cvi42. The time required for evaluation with the PbM was collected. (3) Results: The size of EDV was 177 mL (69-444.5 mL) [average, [minimum-maximum]], ESV was 87 mL (20-361.4 mL), SV was 88 mL and EF was 50% (13-80%) in the pixel-based evaluation. The corresponding values with cvi42 were EDV 193 mL (89-476 mL), ESV 101 mL (34-411 mL), SV 90 mL and EF 45% (12-73%) and syngo.via: EDV 188 mL (74-447 mL), ESV 99 mL (29-358 mL), SV 89 mL (27-176 mL) and EF 47% (13-84%). The comparison between the PbM and KfM showed a negative difference for end-diastolic volume, a negative difference for end-systolic volume and a positive difference for ejection fraction. No difference was seen in stroke volume. The mean papillary muscle volume was calculated to be 14.2 mL. The evaluation with PbM took an average of 2:02 min. (4) Conclusion: PbM is easy and fast to perform for the determination of left ventricular cardiac function. It provides comparable results to the established disc/contour area method in terms of stroke volume and measures "true" left ventricular cardiac function while omitting the papillary muscles. This results in an average 6% higher ejection fraction, which can have a significant influence on therapy decisions.

Insights into synergy-induced multifunctional property enhancement mechanisms in hybrid graphene nanoplatelet reinforced polymer composites

Carbon-based hybrid composites have the potential to simultaneously enhance multiple material functional properties, compared to traditional biphasic composites. In this work, we demonstrate how taking a combined hybrid and hierarchical approach (i.e., polypropylene (PP)-based composite with graphene nanoplatelets (GNPs) coated on glass fibers (GFs), as a secondary micro-sized filler) is effective in multifunctional enhancement, without compromising the composites’ physical properties and mechanical performance. It is demonstrated that the volume exclusion and curvature effects of the highly oriented GFs, produces interconnected GNP clusters with relatively lower interstitial space. Hence, up to 6 orders of magnitude increase in direct-current electrical conductivity of the hybrid composites with 10 vol% GF was observed, relative to its biphasic counterpart. Also, at the percolation region, the hybrid composites reinforced with 10 vol% GF, have demonstrated an approximate 723 % increase in real permittivity. These improvements result in a synergy-induced Ku-band electromagnetic interference shielding effectiveness (EMI SE) of 20.56 dB, which is 81 % higher than that of the biphasic counterpart. Thermal conductivity measurements also showed considerable synergistic effect between the two fillers, whereby the thermal conductivity of the biphasic nanocomposite with 10 vol% GNP increased from 0.67 to 1.09 W/m·K for the hybrid composite containing 10 vol% GF. Such enhancements are accompanied by an approximate 109 % improvement in tensile strength, proving the efficacy of the hybrid approach to simultaneously enhance multiple properties, thereby meeting the requirements for novel practical applications.

Effective hybridization ofSiO2microsphere and graphene with tannic acid interface modifier for fabrication of multifunctional natural rubber/graphene nanocomposites

AbstractNowadays, although highly conductive polymer composites filled with two‐dimensional graphene‐based nano‐fillers have been explored extensively, constructing nanocomposites with high performance, industrial feasibility, and more efficient conductive networks at lower nano‐filler contents remains a challenge. To achieve the above objectives, industrial wastes microsilica powder (N98) with amorphous spherical structure and large particle size is employed in this work. And the hybrids (TGN) are obtained between N98 and graphene (GE) by the effective bridging and interface coupling of tannic acid, which can achieve the purpose of obtaining conductive composites with low‐filler contents by traditional polymer processing technologies. The volume exclusion effect of N98 and its own assisted dispersion effect can prevent and attenuate graphene agglomeration, enabling the formation of a dense, complete and uniform conductive network in natural rubber (NR) matrix based on a small amount of graphene addition (parts per thousand). Thus, it give the nanocomposite highly functional, especially electric property. The results show that when the ratio of GE to N98 hybridization is 1:20, N98 and graphene are more uniformly hybridized together, and the volume exclusion effect is best matched with the rubber composites, and the comprehensive performance is optimal. Moreover, the electrical conductivity of NR/TG1N20nanocomposite can reach the balanced value of 10−3 S·cm−1with the GE loading of 0.48 phr, which shows the effectiveness of the prepared hybrids.

Constructing 3D expanded graphite-silver segregated network structure for ultra-efficient EMI shielding and low reflection

Lightweight, flexible and high-performance (high efficiency and low reflection) electromagnetic interference (EMI) shielding materials are urgently needed to cope with the increasingly complex electromagnetic (EM) radiation environment. In this study, the thermoplastic polyurethane/expanded graphite/silver (TPU/EG/Ag) composite foams with three-dimensional (3D) isolated conductive network were successfully manufactured through the combination of supercritical carbon dioxide (scCO2) foaming and chemical deposition. This composite foam achieves a conductivity up to 171.2 S/m and an EMI SE of 56.3 dB with only 0.58 vol% Ag on account of the volume exclusion of pores and the selective enrichment of Ag nanoparticles. The weight reduction rate of the composite exceeds 74%, and the density of the foamed sample can be as low as 0.21 g/cm3 by introducing a porous structure. Interestingly, the presence of porosity also alleviates impedance mismatch between the composites and air, and the reflectivity of composite is reduced from 99% to 31% owing to the multiple absorption in porous structure, which significantly weakens the serious secondary EM radiation pollution. Moreover, benefiting from the secondary melting at the interface of the TPU isolation unit, these composite foams exhibit favorable compressible recovery performance and shielding stability after 50 cycles of compression. This work proposes a new idea for the lightweight and flexible design of EMI shielding composites, opening a new path for the development of next-generation absorption-based EMI shielding materials.

From single proteins to efficient simulation models of the cytoplasm.

The properties of biomolecules in crowded in-cell environments are governed by interactions that range from repulsive volume exclusions to non-specific transient binding and molecular recognition. Entropic volume exclusion and its impact on biomolecules can be estimated using analytical theory, but transient binding and molecular recognition further depend on electrostatics, hydrogen bonds, van der Waals forces and solvent-mediated interactions. These interactions strongly depend on microscopic details on the molecular scale, which impedes the development of general theories. Instead, computer simulations provide a useful tool to interpret in-cell experiments and to expand our understanding of biomolecular crowding.

Effects of Mitral Valve Prolapse on Quantification of Mitral Regurgitation and Ejection Fraction Using Cardiac MRI.

To determine the impact of prolapsed volume on regurgitant volume (RegV), regurgitant fraction (RF), and left ventricular ejection fraction (LVEF) in patients with mitral valve prolapse (MVP) using cardiac MRI. Patients with MVP and mitral regurgitation who underwent cardiac MRI from 2005 to 2020 were identified retrospectively from the electronic record. RegV is the difference between left ventricular stroke volume (LVSV) and aortic flow. Left ventricular end-systolic volume (LVESV) and LVSV were obtained from volumetric cine images, with prolapsed volume inclusion (LVESVp, LVSVp) and exclusion (LVESVa, LVSVa) providing two estimates of RegV (RegVp, RegVa), RF (RFp, RFa), and LVEF (LVEFa, LVEFp). Interobserver agreement for LVESVp was assessed using intraclass correlation coefficient (ICC). RegV was also calculated independently using measurements from mitral inflow and aortic net flow phase-contrast imaging as the reference standard (RegVg). The study included 19 patients (mean age, 28 years ± 16 [SD]; 10 male patients). Interobserver agreement for LVESVp was high (ICC, 0.98; 95% CI: 0.96, 0.99). Prolapsed volume inclusion resulted in higher LVESV (LVESVp: 95.4 mL ± 34.7 vs LVESVa: 82.4 mL ± 33.8; P < .001), lower LVSV (LVSVp: 100.5 mL ± 33.8 vs LVSVa: 113.5 mL ± 35.9; P < .001), and lower LVEF (LVEFp: 51.7% ± 5.7 vs LVEFa: 58.6% ± 6.3; P < .001). RegV was larger in magnitude when prolapsed volume was excluded (RegVa: 39.4 mL ± 21.0 vs RegVg: 25.8 mL ± 22.8; P = .02), with no evidence of a difference when including prolapsed volume (RegVp: 26.4 mL ± 16.4 vs RegVg: 25.8 mL ± 22.8; P > .99). Measurements that included prolapsed volume most closely reflected mitral regurgitation severity, but inclusion of this volume resulted in a lower LVEF.Keywords: Cardiac, MRI© RSNA, 2023See also commentary by Lee and Markl in this issue.

Towards cell scale agent-based models for membrane cytoskeleton interactions.

The cytoskeleton is a dynamic far-from-equilibrium polymer network. It consumes energy to do mechanical work, and it interacts with complex chemical reaction networks in the cytoplasm and cell membrane to organize into various structures. We will discuss how the MEDYAN (medyan.org) model and software can simulate the chemical and mechanical interactions of actin filaments, crosslinks, myosin motor proteins, and membranes at the micrometer length scale and minute time scale. The next generation of MEDYAN is written in the Julia programming language (MEDYAN.jl). It has significant performance improvements including a 10x faster cylinder volume exclusion algorithm and a 10x faster Gillespie implementation for scheduling chemical reaction events. In addition, it includes an HDF5-based snapshot format that stores the full state of the simulation and enables restarts, and detailed linker and filament aging reactions that have reaction rates that adjust to changes to local monomer states, linker states, and linker mechanics. More complex reactions and reaction rates can be added using user-defined reaction callbacks. It also includes a deformable mesh-based membrane model. MEDYAN.jl is being used to study the role of ARP2/3 in the actin structure in the core of an axon growth cone. MEDYAN.jl is also being used to prototype models of membrane cytoskeleton chemical and mechanical interactions, including activation of ARP2/3.

Dilute polymer solutions under shear flow: Comprehensive qualitative analysis using a bead-spring chain model with a FENE-Fraenkel spring

Although the nonequilibrium behavior of polymer solutions is generally well understood, particularly in extensional flow, there remain several unanswered questions for dilute solutions in simple shear flow, and full quantitative agreement with experiments has not been achieved. For example, experimental viscosity data exhibit qualitative differences in shear-thinning exponents, the shear rate for the onset of shear-thinning, and high-shear Newtonian plateaus depending on polymer semiflexibility, contour length, and solvent quality. While polymer models are able to incorporate all of these effects through various spring force laws, bending potentials, excluded volume (EV) potentials, and hydrodynamic interaction (HI), the inclusion of each piece of physics has not been systematically matched to experimentally observed behavior. Furthermore, attempts to develop multiscale models (in the sense of representing an arbitrarily small or large polymer chain) which can make quantitative predictions are hindered by the lack of ability to fully match the results of bead-rod models, often used to represent a polymer chain at the Kuhn-step level, with bead-spring models, which take into account the entropic elasticity. In light of these difficulties, this work aims to develop a general model based on the so-called FENE-Fraenkel spring, originally formulated by Larson and co-workers [J. Chem. Phys. 124 (2006)], which can span the range from rigid rod to traditional entropic spring, as well as include a bending potential, EV, and HI. As we show, this model can reproduce, and smoothly move between, a wide range of previously observed polymer solution rheology in shear flow.