Cauda equina syndrome (CES) is a rare manifestation in patients with long-standing ankylosing spondylitis (AS). We report a 57-year-old male patient with a 30-year history of AS who developed CES in the past 4 years. The CT and MRI examinations showed unique appearances of dural ectasia, multiple dorsal dural diverticula, erosion of the vertebral posterior elements, tethering of the conus medullaris to the dorsal aspect of the spinal canal and adhesion of the nerve roots of the cauda equina to the wall of the dural sac. A large dural defect was found at surgery. De-adhesion of the tethered conus medullaris was performed but without significant clinical improvement. The possible aetiologies of CES and dural ectasia in patients with chronic AS are discussed and the literature is reviewed.
ABSTRACT. A variety of aetiologies may cause third nerve palsy (TNP), and some manifestations may herald neurological emergencies. This article describes and illustrates various diseases that lead to TNP. The two major functions of the third nerve are oculomotor and pupillomotor. The evaluation of patients with third nerve palsy (TNP) requires an understanding of the normal anatomy of the third nerve. The primary imaging modality used for patients with TNP is MRI because of its high soft-tissue contrast and ability to show the entire course of the third nerve. The MRI sequences used, besides T 1 weighted and T 2 weighted images, should include diffusion-weighted images, MR angiography, thin-slice (,1mm) steady-state free precession (SSFP) and contrast-enhanced spoiled gradientrecalled echo (SGRE) sequences. The current SSFP [e.g. fast imaging employing steady-state acquisition (FIESTA) for a GE scanner; constructive interference steady state (CISS) for a Siemens scanner] and SGRE sequences [e.g. spoiled gradient recalled (SPGR) for a GE scanner; fast low-angle shot (FLASH) for a Siemens scanner] provide submillimetric spatial resolution and are capable of depicting the cisternal segments of all 12 cranial nerves and the relationship of the nerves to pathological processes. They also allow reconstruction in multiplanar images that highlight the course of each cranial nerve (Figure 1). CT scanning is limited in patients with spontaneous subarachnoid haemorrhage (SAH) to exclude cerebral aneurysm and in patients head trauma with suspected skull fracture. Digital subtraction angiography is reserved for cases in which cerebral aneurysm or carotid-cavernous sinus fistula (CCF) is suspected and there is no clue on CT angiography or MR angiography. In this article, we discuss the anatomy and lesions in the
Hepatocyte transplantation as a substitute strategy of orthotopic liver transplantation is being studied for treating end-stage liver diseases. Several technical hurdles must be overcome in order to achieve the therapeutic liver repopulation, such as the problem of insufficient expansion of the transplanted hepatocytes in recipient livers. In this study, we analyzed the application of FoxM1, a cell-cycle regulator, to enhance the proliferation capacity of hepatocytes. The non-viral sleeping beauty (SB) transposon vector carrying FoxM1 gene was constructed for delivering FoxM1 into the hepatocytes. The proliferation capacities of hepatocytes with FoxM1 expression were examined both in vivo and in vitro. Results indicated that the hepatocytes with FoxM1 expression had a higher proliferation rate than wild-type (WT) hepatocytes in vitro. In comparison with WT hepatocytes, the hepatocytes with FoxM1 expression had an enhanced level of liver repopulation in the recipient livers at both sub-acute injury (fumaryl acetoacetate hydrolase (Fah)–/– mice model) and acute injury (2/3 partial hepatectomy mice model). Importantly, there was no increased risk of tumorigenicity with FoxM1 expression in recipients even after serial transplantation. In conclusion, expression of FoxM1 in hepatocytes enhanced the capacity of liver repopulation without inducing tumorigenesis. FoxM1 gene delivered by non-viral SB vector into hepatocytes may be a viable approach to promote therapeutic repopulation after hepatocyte transplantation.
This paper summarizes the report prepared by an IEEE PES Task Force. Resilience is a fairly new technical concept for power systems, and it is important to precisely delineate this concept for actual applications. As a critical infrastructure, power systems have to be prepared to survive rare but extreme incidents (natural catastrophes, extreme weather events, physical/cyber-attacks, equipment failure cascades, etc.) to guarantee power supply to the electricity-dependent economy and society. Thus, resilience needs to be integrated into planning and operational assessment to design and operate adequately resilient power systems. Quantification of resilience as a key performance indicator is important, together with costs and reliability. Quantification can analyze existing power systems and identify resilience improvements in future power systems. Given that a 100% resilient system is not economic (or even technically achievable), the degree of resilience should be transparent and comprehensible. Several gaps are identified to indicate further needs for research and development.
Multilayer electroactive polymer actuators consisting of polypyrrole films electropolymerized on a passive polymer membrane core have been harnessed as a source of simple actuation. As an integral component of the actuator, the membrane plays a vital role in the transport of ionic species and largely dictates the stiffness of the layered configuration, yet in past studies the specification of the membrane has remained largely arbitrary. In this investigation, we use quasi-static and dynamic mechanical analysis to investigate the impact of the mechanical properties of the membrane on the actuation response of polypyrrole-based trilayer bending actuators. Candidate materials with distinctly varied microcellular morphologies are identified and include polyvinylidene difluoride, nylon, and nitrocellulose. The quasi-static stress-strain response and the frequency-dependent viscoelastic nature of the candidates are then evaluated. On the basis of mechanical properties these results indicate that polyvinylidene difluoride membranes are superior to the other candidates for application as trilayer actuator cores. Bis(trifluoromethane)sulfonimide doped polypyrrole actuators with polyvinylidene difluoride cores and nylon cores are then fabricated under various synthesis conditions and their electromechanical actuation behavior is reported.
The study of intricate cellular and developmental processes in the context of complex multicellular organisms is difficult because it can require the non-destructive observation of thousands, millions, or even billions of cells deep within an animal. To address this difficulty, several groups have recently reported CRISPR-based DNA recorders that convert transient cellular experiences and processes into changes in the genome, which can then be read by sequencing in high-throughput. However, existing DNA recorders act primarily by erasing DNA: they use the random accumulation of CRISPR-induced deletions to record information. This is problematic because in the limit of progressive deletion, no record remains. Here, we present a new type of DNA recorder that acts primarily by writing new DNA. Our system, called CHYRON (Cell HistorY Recording by Ordered iNsertion), inserts random nucleotides at a single locus in temporal order in vivo and can be applied as an evolving lineage tracer as well as a recorder of user-selected cellular stimuli. As a lineage tracer, CHYRON allowed us to perfectly reconstruct the population lineage relationships among 16 groups of human cells descended from four starting groups that were subject to a series of splitting steps. In this experiment, CHYRON progressively wrote and retained base insertions in 20% percent of cells where the average amount written was 8.4 bp (~14.5 bits), reflecting high information content and density. As a stimulus recorder, we showed that when the CHYRON machinery was placed under the control of a stress-responsive promoter, the frequency and length of writing reflected the dose and duration of the stress. We believe CHYRON represents a conceptual advance in DNA recording technologies where writing rather than erasing becomes the primary mode of information accumulation. With further engineering of CHYRON's components to increase writing efficiency, CHYRON should lead to single-cell-resolution recording of lineage and other information through long periods of time in complex animals or tumors, advancing the pursuit of a full picture of mammalian development.
To improve the reliability of vehicle state parameter estimation, a vehicle state fusion estimation method based on dichotomy is proposed. An extended Kalman filter algorithm is designed based on the vehicle 3 degrees of freedom dynamic model. Meanwhile, considering the influence of dynamic model and sensor noise and its coefficient selection on the estimation results, a radial basis function neural network estimation algorithm is designed. To further improve the reliability of the estimation algorithm, a method of estimation algorithm fusion is proposed based on the idea of mutual compensation between model- and data-driven estimation algorithms. The weights of the estimation results of different algorithms are assigned through the dichotomy. The redundancy and fusion of estimation algorithms can improve estimation performance. The effectiveness of the fusion method is verified by the co-simulation of MATLAB/Simulink and CarSim, and the real vehicle test. The results show that the change trend of the estimation result is consistent with the actual state parameters change trend, and the estimation accuracy after algorithm fusion is significantly improved compared to a single extended Kalman filter or radial basis function.
Synaptic molecular characterization is limited for Alzheimers disease (AD). We used mass cytometry to quantify 38 probes in approximately 17 million single synaptic events from human brains without pathologic change or with pure AD or Lewy body disease (LBD), non-human primates (NHP), and PS/APP mice. Synaptic molecular integrity in humans and NHP was similar. Although not detected in human synapses, Aβ was in PS/APP mice synaptic events. Clustering and pattern identification of human synapses showed expected disease-specific differences, like increased hippocampal pathologic tau in AD and reduced caudate dopamine transporter in LBD, and revealed novel findings including increased hippocampal CD47 and lowered DJ1 in AD and higher ApoE in AD dementia. Our results were independently supported by multiplex ion beam imaging of intact tissue.
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