Clinical prediction rule for early recovery of knee range of motion after total knee arthroplasty: A prospective cohort study

Objective: To derive a clinical prediction rule for early recovery of knee range of motion after total knee arthroplasty. Methods: This prospective cohort study evaluated the data of 273 individuals undergoing primary total knee arthroplasty. The individual factors, the physical and motor function data were assessed preoperatively upon admission as a baseline survey. The knee joint extension angle and knee joint flexion angle were re-evaluated on postoperative day 14 as a follow-up. The recovery group comprised individuals with a knee joint extension angle of more than -5 degrees and knee joint flexion angle of more than 110 degrees on postoperative day 14. The other patients constituted the non-recovery group. Multivariate logistic regression analysis was used for deriving a clinical prediction rule. Results: The results indicated that the use of a cane, knee joint extension and flexion angles, and Timed Up and Go test time were significant factors for predicting early recovery of knee range of motion after total knee arthroplasty. Furthermore, a clinical prediction rule was derived and included the use of a cane, knee joint extension angle ≥ -15 degrees, knee joint flexion angle ≥ 125 degrees, and a Timed Up and Go test time < 11.2 s. A total clinical prediction rule score ≥ 8 indicated a positive likelihood ratio of more than 10 for a successful outcome and the post-test probability was approximately 95%. Conclusions: The derived clinical prediction rule might be a useful screening tool for proper postoperative goal setting and the establishment of individualized physical therapy programs.     

Discrimination of Patients with Varying Degrees of Coronary Artery Stenosis by ECG and PCG Signals Based on Entropy

Coronary heart disease (CHD) is the leading cause of cardiovascular death. This study aimed to propose an effective method for mining cardiac mechano-electric coupling information and to evaluate its ability to distinguish patients with varying degrees of coronary artery stenosis (VDCAS). Five minutes of electrocardiogram and phonocardiogram signals was collected synchronously from 191 VDCAS patients to construct heartbeat interval (RRI)–systolic time interval (STI), RRI–diastolic time interval (DTI), HR-corrected QT interval (QTcI)–STI, QTcI–DTI, Tpeak–Tend interval (TpeI)–STI, TpeI–DTI, Tpe/QT interval (Tpe/QTI)–STI, and Tpe/QTI–DTI series. Then, the cross sample entropy (XSampEn), cross fuzzy entropy (XFuzzyEn), joint distribution entropy (JDistEn), magnitude-squared coherence function, cross power spectral density, and mutual information were applied to evaluate the coupling of the series. Subsequently, support vector machine recursive feature elimination and XGBoost were utilized for feature selection and classification, respectively. Results showed that the joint analysis of XSampEn, XFuzzyEn, and JDistEn had the best ability to distinguish patients with VDCAS. The classification accuracy of severe CHD—mild-to-moderate CHD group, severe CHD—chest pain and normal coronary angiography (CPNCA) group, and mild-to-moderate CHD—CPNCA group were 0.8043, 0.7659, and 0.7500, respectively. The study indicates that the joint analysis of XSampEn, XFuzzyEn, and JDistEn can effectively capture the cardiac mechano-electric coupling information of patients with VDCAS, which can provide valuable information for clinicians to diagnose CHD.     

Upright MRI of glenohumeral dysplasia following obstetric brachial plexus injury

The purpose of this study was to evaluate the role of upright magnetic resonance imaging (MRI) shoulder scanning in the diagnosis of glenohumeral deformity following obstetric brachial plexus injury (OBPI). Eighty-nine children (ages 0.4 to 17.9 years) with OBPI who have medial rotation contracture and reduced passive and active lateral rotation of the shoulder were evaluated via upright MRI of the affected glenohumeral joint. Qualitative impressions of glenoid form were recorded, and quantitative measurements were made of glenoid version and posterior subluxation. Glenoid version of the affected shoulder averaged -16.8 +/- 11.0 degrees (range, -55 degrees to 1 degrees ), and percentage of the humeral head anterior to the glenoid fossa (PHHA) averaged 32.6 +/- 16.5% (range, -17.8% to 52.4%). The glenoid form was normal in 43 children, convex in 19 children and biconcave in 27 children. Standard MRI protocols were used to obtain bilateral images from 14 of these patients. Among the patients with bilateral MR images, glenoid version and PHHA were significantly different between the involved and uninvolved shoulders (P<.000). Glenoid version in the involved shoulder averaged -19.0 +/- 13.1 degrees (range, -52 degrees to -3 degrees ), and PHHA averaged 29.7 +/- 18.4% (range, -16.2% to 48.7%). In the uninvolved shoulder, the average glenoid version and PHHA were -5.2 +/- 3.7 degrees (range, -12 degrees to -1 degrees ) and 47.7 +/- 3.0% (range, 43% to 54%), respectively. The relative beneficial aspects of upright MRI include lack of need for sedation, low claustrophobic potential and, most important, natural, gravity-influenced position, enabling the surgeon to visualize the true preoperative picture of the shoulder. It is an effective tool for demonstrating glenohumeral abnormalities resulting from brachial plexus injury worthy of surgical exploration.     

A Thermodynamic Approach to Measuring Entropy in a Few-Electron Nanodevice

The entropy of a system gives a powerful insight into its microscopic degrees of freedom; however, standard experimental ways of measuring entropy through heat capacity are hard to apply to nanoscale systems, as they require the measurement of increasingly small amounts of heat. Two alternative entropy measurement methods have been recently proposed for nanodevices: through charge balance measurements and transport properties. We describe a self-consistent thermodynamic framework for applying thermodynamic relations to few-electron nanodevices—small systems, where fluctuations in particle number are significant, whilst highlighting several ongoing misconceptions. We derive a relation (a consequence of a Maxwell relation for small systems), which describes both existing entropy measurement methods as special cases, while also allowing the experimentalist to probe the intermediate regime between them. Finally, we independently prove the applicability of our framework in systems with complex microscopic dynamics—those with many excited states of various degeneracies—from microscopic considerations.     

Elastic AlignedSENSE for Dynamic MR Reconstruction: A Proof of Concept in Cardiac Cine

Numerous methods in the extensive literature on magnetic resonance imaging (MRI) reconstruction exploit temporal redundancy to accelerate cardiac cine. Some of them include motion compensation, which involves high computational costs and long runtimes. In this work, we proposed a method—elastic alignedSENSE (EAS)—for the direct reconstruction of a motion-free image plus a set of nonrigid deformations to reconstruct a 2D cardiac sequence. The feasibility of the proposed approach was tested in 2D Cartesian and golden radial multi-coil breath-hold cardiac cine acquisitions. The proposed approach was compared against parallel imaging compressed sense (sPICS) and group-wise motion corrected compressed sense (GWCS) reconstructions. EAS provides better results on objective measures with considerable less runtime when an acceleration factor is higher than 10×. Subjective assessment of an expert, however, invited proposing the combination of EAS and GWCS as a preferable alternative to GWCS or EAS in isolation.     

Dynamics of Ultracold Bosons in Artificial Gauge Fields—Angular Momentum,Fragmentation, and the Variance of Entropy

We consider the dynamics of two-dimensional interacting ultracold bosons triggered by suddenly switching on an artificial gauge field. The system is initialized in the ground state of a harmonic trapping potential. As a function of the strength of the applied artificial gauge field, we analyze the emergent dynamics by monitoring the angular momentum, the fragmentation as well as the entropy and variance of the entropy of absorption or single-shot images. We solve the underlying time-dependent many-boson Schrödinger equation using the multiconfigurational time-dependent Hartree method for indistinguishable particles (MCTDH-X). We find that the artificial gauge field implants angular momentum in the system. Fragmentation—multiple macroscopic eigenvalues of the reduced one-body density matrix—emerges in sync with the dynamics of angular momentum: the bosons in the many-body state develop non-trivial correlations. Fragmentation and angular momentum are experimentally difficult to assess; here, we demonstrate that they can be probed by statistically analyzing the variance of the image entropy of single-shot images that are the standard projective measurement of the state of ultracold atomic systems.     

宽带啁啾镜对的设计和制备

设计了中心波长800 nm带宽约500 nm的啁啾镜对, 在550–1050 nm波长范围内提供约-60 fs²群延迟色散(group delay dispersion, GDD), 通过啁啾镜对的形式使GDD振荡波纹由单个啁啾镜的±100 fs²减小到±20 fs². 采用双射频离子束溅射方法进行制备, 用白光干涉仪进行色散性能测试, 从测试结果可以看出, 制备的啁啾镜的反射率、GDD性能和设计值符合得比较好. 制备出的550–1050 nm超宽带啁啾镜对在钛宝石激光器腔外进行色散补偿, 原输入脉冲由24–27 fs压缩到12 fs, 这是国产超宽带啁啾镜对的首次应用. 关键词： 超快激光 啁啾镜对 群延迟色散 色散补偿     

Ambiguities Appearing in the Study of Time-Dependent Constants of Motion for the One-Dimensional Harmonic Oscillator

A family of time-dependent constants of motionfor the one-dimensional harmonic oscillator is derived.The relation between constants of motion, Lagrangian,and Hamiltonian is described. A well-defined time-dependent Lagrangian (for whichEuler–Lagrange equations and Legendretransformation are fully satisfied) is not uniquelydetermined.     

Gravitationally Induced Decoherence in Macroscopic Systems

A quantum master equation for the time evolution of the center of mass (CM) of a macroscopic body is derived which takes into account the influence of the system's gravitational field over the CM wave function. As a consequence, all the relevant phenomenological features of the so-called GRW (Ghirardi, Rimini, and Weber) model are reproduced with no free parameters. The model presented here predicts also the existence of a transition region for the mass of the system—a kind of frontier between quantum (coherent) and classical (decoherent) behavior.     

A Toss without a Coin: Information,Discontinuity, and Mathematics in Quantum Theory

The article argues that—at least in certain interpretations, such as the one assumed in this article under the heading of “reality without realism”—the quantum-theoretical situation appears as follows: While—in terms of probabilistic predictions—connected to and connecting the information obtained in quantum phenomena, the mathematics of quantum theory (QM or QFT), which is continuous, does not represent and is discontinuous with both the emergence of quantum phenomena and the physics of these phenomena, phenomena that are physically discontinuous with each other as well. These phenomena, and thus this information, are described by classical physics. All actually available information (in the mathematical sense of information theory) is classical: it is composed of units, such as bits, that are—or are contained in—entities described by classical physics. On the other hand, classical physics cannot predict this information when it is created, as manifested in measuring instruments, in quantum experiments, while quantum theory can. In this epistemological sense, this information is quantum. The article designates the discontinuity between quantum theory and the emergence of quantum phenomena the “Heisenberg discontinuity”, because it was introduced by W. Heisenberg along with QM, and the discontinuity between QM or QFT and the classical physics of quantum phenomena, the “Bohr discontinuity”, because it was introduced as part of Bohr’s interpretation of quantum phenomena and QM, under the assumption of Heisenberg discontinuity. Combining both discontinuities precludes QM or QFT from being connected to either physical reality, that ultimately responsible for quantum phenomena or that of these phenomena themselves, other than by means of probabilistic predictions concerning the information, classical in character, contained in quantum phenomena. The nature of quantum information is, in this view, defined by this situation. A major implication, discussed in the Conclusion, is the existence and arguably the necessity of two—classical and quantum—or with relativity, three and possibly more essentially different theories in fundamental physics.     

Influence of salicylic acid on the biophysical properties of dipalmitoyl phosphatidylcholine vesicles

The effect of the keratolytic drug salicylic acid (SA) on the thermotropic behaviour, and dynamics of dipalmitoyl phosphatidyl choline (DPPC)–water/buffer pH?7.4 vesicles was studied using DSC and ¹H NMR. In both systems, incorporation of SA in DPPC bilayer causes a significant depression in the transition temperature of both the pre-transition (PT) and the gel-to-liquid crystalline (CM) transition. The presence of the drug reduces the cooperativity of both the PT and CM transitions. These findings indicate that SA is bound strongly to the lipid bilayer leading to increased membrane fluidity. The DPPC vesicles incorporated with high drug concentration show phase segregation. One of the interesting findings in this study is the formation of a more ordered high temperature gel (L_β2) phase when the SA-doped DPPC dispersion is prepared at physiological pH. The effect of inclusion of cholesterol in the SA-free and SA-doped DPPC dispersion was also studied.     

Modelling resonances of the standing body exposed to vertical whole-body vibration: Effects of posture

Lumped parameter mathematical models representing anatomical parts of the human body have been developed to represent body motions associated with resonances of the vertical apparent mass and the fore-and-aft cross-axis apparent mass of the human body standing in five different postures: ‘upright’, ‘lordotic’, ‘anterior lean’, ‘knees bent’, and ‘knees more bent’. The inertial and geometric parameters of the models were determined from published anthropometric data. Stiffness and damping parameters were obtained by comparing model responses with experimental data obtained previously.The principal resonance of the vertical apparent mass, and the first peak in the fore-and-aft cross-axis apparent mass, of the standing body in an upright posture (at 5–6 Hz) corresponded to vertical motion of the viscera in phase with the vertical motion of the entire body due to deformation of the tissues at the soles of the feet, with pitch motion of the pelvis out of phase with pitch motion of the upper body above the pelvis. Upward motion of the body was in phase with the forward pitch motion of the pelvis. Changing the posture of the upper body had minor effects on the mode associated with the principal resonances of the apparent mass and cross-axis apparent mass, but the mode changed significantly with bending of the legs. In legs-bent postures, the principal resonance (at about 3 Hz) was attributed to bending of the legs coupled with pitch motion of the pelvis in phase with pitch motion of the upper body. In this mode, extension of the legs was in phase with the forward pitch motion of the upper body and the upward vertical motion of the viscera.     

Exploration and Exploitation Zones in a Minimalist Swarm Optimiser

The trade off between exploration and exploitation is one of the key challenges in evolutionary and swarm optimisers which are led by guided and stochastic search. This work investigates the exploration and exploitation balance in a minimalist swarm optimiser in order to offer insights into the population’s behaviour. The minimalist and vector-stripped nature of the algorithm—dispersive flies optimisation or DFO—reduces the challenges of understanding particles’ oscillation around constantly changing centres, their influence on one another, and their trajectory. The aim is to examine the population’s dimensional behaviour in each iteration and each defined exploration-exploitation zone, and to subsequently offer improvements to the working of the optimiser. The derived variants, titled unified DFO or uDFO, are successfully applied to an extensive set of test functions, as well as high-dimensional tomographic reconstruction, which is an important inverse problem in medical and industrial imaging.     

Multiscale Entropy Analysis of Short Signals: The Robustness of Fuzzy Entropy-Based Variants Compared to Full-Length Long Signals

Multiscale entropy (MSE) analysis is a fundamental approach to access the complexity of a time series by estimating its information creation over a range of temporal scales. However, MSE may not be accurate or valid for short time series. This is why previous studies applied different kinds of algorithm derivations to short-term time series. However, no study has systematically analyzed and compared their reliabilities. This study compares the MSE algorithm variations adapted to short time series on both human and rat heart rate variability (HRV) time series using long-term MSE as reference. The most used variations of MSE are studied: composite MSE (CMSE), refined composite MSE (RCMSE), modified MSE (MMSE), and their fuzzy versions. We also analyze the errors in MSE estimations for a range of incorporated fuzzy exponents. The results show that fuzzy MSE versions—as a function of time series length—present minimal errors compared to the non-fuzzy algorithms. The traditional multiscale entropy algorithm with fuzzy counting (MFE) has similar accuracy to alternative algorithms with better computing performance. For the best accuracy, the findings suggest different fuzzy exponents according to the time series length.     

Stochastic Chaos and Markov Blankets

In this treatment of random dynamical systems, we consider the existence—and identification—of conditional independencies at nonequilibrium steady-state. These independencies underwrite a particular partition of states, in which internal states are statistically secluded from external states by blanket states. The existence of such partitions has interesting implications for the information geometry of internal states. In brief, this geometry can be read as a physics of sentience, where internal states look as if they are inferring external states. However, the existence of such partitions—and the functional form of the underlying densities—have yet to be established. Here, using the Lorenz system as the basis of stochastic chaos, we leverage the Helmholtz decomposition—and polynomial expansions—to parameterise the steady-state density in terms of surprisal or self-information. We then show how Markov blankets can be identified—using the accompanying Hessian—to characterise the coupling between internal and external states in terms of a generalised synchrony or synchronisation of chaos. We conclude by suggesting that this kind of synchronisation may provide a mathematical basis for an elemental form of (autonomous or active) sentience in biology.     

Classical and path-integral molecular-dynamics study on liquid water and ice melting using non-empirical TTM2.1-F model

The TTMF2.1-F model is a non-empirical intermolecular water potential parametrised from ab-initio calculations of the water dimer with a complete basis set limit including dispersion correction from second-order Moller-Plesset perturbation theory. In this work, using two-phase ice-water NVT molecular-dynamics (MD) simulations, we found the ice melting temperature using the TTM2.1-F potential is close to 273?K when the nuclear quantum effects (NQEs) were included using path-integral centroid MD. Detailed analysis of the radial distribution functions, angle distribution functions, and associated joint probability for both liquid water and the two-phase cases showed that the melting-point-temperature drop when using path-integral simulation is due to the weakening of hydrogen bonds vis-à-vis classically-propagated MD.     

A large-eddy simulation of buoyant plumes in a convective boundary layer

Summary By means of a large-eddy simulation technique, the time-dependent large-scale flow field of a convective atmospheric boundary layer has been claculated. Using a conservation equation for the concentration dispersion we applied this simulation technique to dispersion from both passive and buoyant sources. The results were found to be in good agreement with laboratory and field experiments. It was possible to separate the mean plume motion into a part induced by convective turbulence and a part induced by plume buoyancy. We found that the part of the plume motion caused by convective turbulence was strongly influenced by plume buoyancy. On the other hand, it appears that the large-scale motions of convective turbulence have a strong influence on the entrainment processes governing the motion due to buoyancy. Paper presented at the GNFAO/EURASAP Meeting, Turin, September 1989. To speed up publication, proofs were not sent to the authors and were supervised by the Scientific Committee.     

Monte Carlo Simulation of Stochastic Differential Equation to Study Information Geometry

Information Geometry is a useful tool to study and compare the solutions of a Stochastic Differential Equations (SDEs) for non-equilibrium systems. As an alternative method to solving the Fokker–Planck equation, we propose a new method to calculate time-dependent probability density functions (PDFs) and to study Information Geometry using Monte Carlo (MC) simulation of SDEs. Specifically, we develop a new MC SDE method to overcome the challenges in calculating a time-dependent PDF and information geometric diagnostics and to speed up simulations by utilizing GPU computing. Using MC SDE simulations, we reproduce Information Geometric scaling relations found from the Fokker–Planck method for the case of a stochastic process with linear and cubic damping terms. We showcase the advantage of MC SDE simulation over FPE solvers by calculating unequal time joint PDFs. For the linear process with a linear damping force, joint PDF is found to be a Gaussian. In contrast, for the cubic process with a cubic damping force, joint PDF exhibits a bimodal structure, even in a stationary state. This suggests a finite memory time induced by a nonlinear force. Furthermore, several power-law scalings in the characteristics of bimodal PDFs are identified and investigated.     

Electrical Mobility Magnetic Resonance Spectroscopy (EMMRS)

A method to determine electrical mobility of charge carriers containing paramagnetic elements is presented. The motion-induced phase shift of the transverse magnetization component is observed by magnetic (nuclear or electron) resonance (MR). In fluid media, this method can determine the type of carriers and respective motion, lifetimes distribution, thermal and frequency dispersion of the mobility, translational relaxation rate and activation energies of these processes.