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关键词： MRI   Spine   Spondylodiscitis   Tuberculous   Pyogenic  

摘要： Purpose The aim of the study was to investigate whether MRI findings together with epidemiological data could help in differentiating between tuberculous and pyogenic spondylodiscitis. Methods Clinical records of 260 patients with a suspicion of spondylodiscitis were analysed. Patients were selected using the following inclusion criteria: confirmed diagnosis of spondylodiscitis either from pyogenic bacteria or from Mycobacterium tuberculosis and contrast-enhanced MRI performed before treatment. Clinical data concerning age, sex and country-of-origin were also collected. For each patient, several MRI-features were evaluated by two-expert musculoskeletal radiologists. A chi-squared test and a multiple logistic regression were used to find the best predictors of tuberculous or pyogenic spondylodiscitis. Results 114 patients were retrospectively enrolled, 30 with tuberculous and 84 with pyogenic spondylodiscitis. We found 18 MRI-features, significantly different between the two groups. Among these, the most strongly associated with tuberculous spondylodiscitis were: heterogeneous vertebral signal on T1w-sequences (Odds Ratio(OR) = 205.759-p < 0.001), presence of epidural abscess (OR = 86.221-p < 0.001), severe vertebral destruction (OR = 10.017-p < 0.001) and absence of epidural phlegmon (OR = 86.221-p < 0.001). Moreover, patients coming from countries with a middle-high prevalence of tuberculosis were more frequently affected by tuberculous spondylodiscitis than others were (OR = 229.136-p < 0.001). The best prediction model demonstrated a correct classification rate of 94.7%. Conclusion To the best of our knowledge this is the largest study comparing MRI-features of tuberculous and pyogenic spondylodiscitis. The above-mentioned MRI-features and epidemiological data are crucial in the differential diagnosis between these two entities, guiding the choice of the appropriate therapy, especially when a pathogen cannot be clearly identified with other modalities.

关键词： Multi-agent systems   Intrinsic formation control   Differential games  

摘要： This paper addresses the formation control problem of a multi-agent system in a non-cooperative differential game framework. Both finite horizon and infinite horizon games are considered and their Nash equilibria are studied. The desired formation patterns are achieved by Nash equilibrium strategies in an intrinsic way in the sense that they are only attributed to the inter-agent interaction and geometric properties of the network, where the desired formations are not designated directly in the controller. The whole formation manifold of the desired relative pattern is studied by allowing all orientations of the formation and all permutations of the agents. For finite horizon games the terminal formation of Nash equilibrium trajectories is shown to converge to desired pattern as the length of the time interval tends to infinity. Furthermore the asymptotic stability of the desired formation manifold is also guaranteed in infinite horizon games. Relative patterns of regular polyhedra and antipodal formations are achieved by designing the interaction graph while inter-agent collisions are avoided. Finally, numerical simulations are provided to demonstrate the effectiveness and feasibility of the proposed methods. (C) 2021 The Author(s). Published by Elsevier Ltd.

关键词： mesothelioma   peritoneal   ovarian cancer   serous carcinoma   SOX6   immunohistochemistry  

摘要： Primary peritoneal malignant mesothelioma (MM) can demonstrate morphologic overlap with low-grade and high-grade tubo-ovarian serous neoplasms;it is also biologically and prognostically distinct from benign mesothelial proliferations. Currently, there is no single biomarker that can definitively distinguish these neoplasms. Sex-determining region Y box 6 (SOX6) immunohistochemistry has been recently described to differentiate pleural epithelioid MM from lung adenocarcinoma, but it has not been evaluated in the peritoneum. SOX6 immunohistochemistry was performed on 43 peritoneal epithelioid MM, 7 peritoneal biphasic MM, 5 well-differentiated papillary mesotheliomas, 5 serous borderline tumors, 29 low-grade serous carcinomas (LGSCs), 20 high-grade serous carcinomas (HGSCs), and 25 cases of peritoneal reactive mesothelial hyperplasia. Quantitative SOX6 expression in epithelioid MM (median, 100% of tumor cells) was significantly greater than in LGSC/serous borderline tumor (median, 90%;P=0.004) and HGSC (median, 45%;P=0.0001). However, when SOX6 is expression is defined as >= 10% of tumor cells, there was no significant difference in the rate of SOX6 positivity between epithelioid MM (41/43, 95%), LGSC (28/29, 97%;P=1.0), and HGSC (17/20, 85%;P=0.16). Quantitative extent of SOX6 expression in epithelioid MM was significantly greater than in biphasic MM (median, 0%;P=0.0001), well-differentiated papillary mesothelioma (median, 20%;P=0.001), and reactive mesothelial hyperplasia (median, 20%;P=0.0001), but not significantly different from flat quiescent mesothelium (median, 90%;P=0.82). SOX6 immunohistochemistry is 95% sensitive for peritoneal epithelioid MM, but is also consistently expressed in LGSC and HGSC, negating its usefulness in this common differential diagnosis. SOX6 also shows variable expression across the spectrum of reactive, benign neoplastic, and malignant mesothelial lesions of the peritoneum, and does not appear to be diagnostically useful in distinguish

关键词： Fractional differential equation   Caputo derivative   Initial condition   Separation of solutions  

摘要： Given a fractional differential equation of order alpha is an element of (0, 1] with Caputo derivatives, we investigate in a quantitative sense how the associated solutions depend on their respective initial conditions. Specifically, we look at two solutions x(1) and x(2), say, of the same differential equation, both of which are assumed to be defined on a common interval [0, T], and provide upper and lower bounds for the difference x(1) (t) -x(2)(t) for all t is an element of [0, T] that are stronger than the bounds previously described in the literature.

关键词： Gallium-arsenide (GaAs)   negative differential mobility (NDM)   photoconductive switch   pulse compression  

摘要： This work demonstrates a novel optoelectronic device with the potential for use as a high-frequency, high-power RF source or amplifier. The device is a gallium-arsenide coplanar waveguide with a small gap in the signal trace for optical illumination. A confined charge cloud is generated by illumination through an aperture in an opaque mask over this gap. An electric field above the threshold for negative differential mobility (NDM) enables pulse compression, which prevents the charge cloud from spreading temporally during the drift process. Due to the NDM phenomenon, the output electrical pulse is temporally compressed compared to the input optical pulse. This phenomenon is demonstrated using three different experiments with varied laser pulsewidth (28-700 ps) and device geometry (50- and 100-mu m-length gaps). A 66% reduction in the full-width at half-maximum of the electrical pulse relative to the input optical pulse was demonstrated. This novel coupled optoelectronic device opens avenues for high-frequency, high-power, compact devices that could enable next-generation satellite communication systems with faster data rates and longer ranges.

关键词： health care workers   injury compensation   musculoskeletal   occupational injury  

摘要： Background The Minnesota Safe Patient Handling (MN SPH) Act requires health care facilities to implement comprehensive programs to protect their workers from musculoskeletal injuries caused by lifting and transferring patients. Nursing homes, hospitals, and outpatient facilities each face unique challenges implementing and maintaining SPH programs. The objective of the study was to compare patient handling injuries in these three health care settings and determine whether change in injury rate over time differed by setting following enactment of the law. Methods Workers' compensation data from a Minnesota-based insurer were used to describe worker and claim characteristics in nursing homes, hospitals, and outpatient facilities. Negative binomial models were used to compare claims and estimate mean annual patient handling claim rates by health care setting and time period following enactment of the law. Results Consistent with national data, the patient handling claim rate was highest in Minnesota nursing homes (168 claims/$100 million payroll [95% confidence interval: 163-174]) followed by hospitals (35/$100 million payroll [34-37]) and outpatient facilities (2/$100 million payroll [1.8-2.2]). Patient handling claims declined by 38% over 10 years following enactment of the law (vs. 27% for all other claims). The change in claims over time did not differ by health care setting. Conclusions In this single-insurer sample, declines in workers' compensation claims for patient handling injuries were consistent across health care settings following enactment of a state SPH law. Though nursing homes experienced elevated claim rates overall, results suggest they are not lagging hospitals and outpatient facilities in reducing patient handling injuries.

关键词： Differential Galois theory   Parameterized Picard-Vessiot theory   Difference algebraic groups   Inverse problems  

摘要： We study the inverse problem in the difference Galois theory of linear differential equations over the difference-differential field C(x) with derivation d/dx and endomorphism f(x) -> f (x + 1). Our main result is that every linear algebraic group, considered as a difference algebraic group, occurs as the difference Galois group of some linear differential equation over C(x). (C) 2021 Elsevier B.V. All rights reserved.

关键词： Surgical Oncology   Oncology   Surgery  

摘要： Objective The aim of this study was to compare functional outcomes after partial nephrectomy (PN) between moderate and high complex renal tumors evaluated with a diethylenetriamine pentaacetic acid (DTPA) scan [moderate vs. high: RENAL nephrometry score (RNS) 7-9 vs. 10-12]. Methods From January 2004 to December 2019, 471 patients with an RNS of 7-9 (moderate) and 164 patients with an RNS of 10-12 (high) who underwent PN were analyzed for renal function outcomes. The glomerular filtration rate (GFR) was measured using a DTPA scan and calculated the GFR using the Modification of Diet in Renal Disease (MDRD) formula, respectively. Trifecta/pentafecta outcome, recurrence-free survival, and overall survival were compared after propensity score matched analysis (PSMA). Results After PSMA, 156 cases in each group were matched without significant difference in the preoperative factor. At the postoperative first year, there was no significant difference in the trifecta (p = 0.320), MDRD-based (p = 0.729), or DTPA-based pentafecta achievement rate (p = 0.964) between groups. At postoperative 5 years, DTPA-based total GFR (93.6% vs. 93.8%) and the operated kidney GFR preservation rate (89.9% vs. 81.7%) did not differ significantly (p > 0.05). Kaplan-Meier survival analysis showed no significant differences in survival outcomes (p > 0.05). Significant predictors of de novo chronic kidney disease (CKD) stage 3 or higher at the postoperative first year were age [hazard ratio (HR) 1.10, 95% confidence interval (CI) 1.03-1.17, p = 0.005] and preoperative DTPA-based total GFR (HR 0.94, 95% CI 0.91-0.98, p = 0.001). Conclusion High complex tumors can be treated with PN without significant deterioration in renal function. The postoperative function of the operated kidney was preserved by up to 80% in the long term compared with the preoperative period. However, PN should be selectively performed with caution to avoid the occurrence of postoperative CKD.

关键词： controlled invariant submanifolds   constrained mechanical system   differential-algebraic control systems   explicitation   external and internal feedback equivalence   feedback linearization  

摘要： In this article, we study feedback linearization problems for nonlinear differential-algebraic control systems (DACSs). We consider two kinds of feedback equivalences, namely, external feedback equivalence, which is defined (locally) on the whole generalized state space, and internal feedback equivalence, which is defined on the locally maximal controlled invariant submanifold (i.e., on the set where solutions exist). We define a notion called explicitation with driving variables, which is a class of ordinary differential equation control systems (ODECSs) attaching to a given DACS. Then we give necessary and sufficient conditions for both internal and external feedback linearization problems of the DACS. We show that the feedback linearizability of the DACS is closely related to the involutivity of the linearizability distributions of the explicitation systems. Finally, we illustrate the results of the by an academic example and a constrained mechanical system.

关键词： Stochastic Volterra integro-differential equations   theta-EM method   Mean square exponential stability   Almost sure exponential stability  

摘要： Mean square exponential stability of both exact solutions and the corresponding theta- EM method for stochastic Volterra integro-differential equations are investigated in this paper. For 1/2 < theta <= 1, we prove that both exact solutions and the corresponding theta-EM method for stochastic Volterra integro-differential equations are mean square exponentially stable under the Khasminskii-type conditions. If 0 <= theta <= 1/2, theta-EM method is mean square exponentially stable under the Khasminskii-type condition plus linear growth condition on f. By using Chebyshev inequality and Borel-Cantelli lemma, we can also prove that theta-EM method is almost surely exponentially stable. An example is provided to support our conclusions. (C) 2021 IMACS. Published by Elsevier B.V. All rights reserved.