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The aim of the study is to provide an up-to-date review of studies that used preclinical animal models for the evaluation of tissue engineering treatments for spinal cord injury (SCI), which involved the use of biomaterials with o...
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The aim of the study is to provide an up-to-date review of studies that used preclinical animal models for the evaluation of tissue engineering treatments for spinal cord injury (SCI), which involved the use of biomaterials with or without the addition of cells or biomolecules. Electronic search of the PubMed, Web of Science, and Embase databases was performed for relevant studies published between January 2009 and December 2019. In total, 1579 articles were retrieved, of which 58 studies were included for analysis. Among the included studies, rats were the most common species used for animal models of SCI, while complete transection was the most commonly used injury pattern. Immediate intervention after injury was conducted in the majority of studies, and 8 weeks was the most common final time point of outcome assessment. A wide range of natural and synthetic biomaterials with different morphologies were used as a part of tissue engineering treatments for SCI, including scaffolds, hydrogels, and particles. Experimental parameters in studies using SCI animal models to evaluate tissue engineering treatments should be carefully considered to match the purpose of the study. Biomaterials that have functional modifications or are applied in combination with cells and biomolecules can be effective in creating a permissive environment for SCI repair in preclinical animal models. This review provides an up-to-date summary of the preclinical landscape where tissue engineering treatments involving biomaterials were tested in animal models of spinal cord injury (SCI). Using studies published within the last 10 years, novel perspectives were presented on the animal species used, injury pattern, timing of intervention and outcome measurement, and biomaterials selection, as well as a summary of the individual findings of each study. This review provides unique insight into biomaterials-based tissue engineering strategies that have progressed to testing in animal models of SCI, which will help shape future research in the field and propel the clinical translation of discoveries. ? Copyright 2022, Mary Ann Liebert, Inc.
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Let $(X, d, \mu)$ be a metric measure space endowed with a distance $d$ and a nonnegative Borel doubling measure $\mu$. Let $L$ be a non-negative self-adjoint operator of order $m$ on $L^2(X)$. Assume that the semigroup $ e^{-tL}$...
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Let $(X, d, \mu)$ be a metric measure space endowed with a distance $d$ and a nonnegative Borel doubling measure $\mu$. Let $L$ be a non-negative self-adjoint operator of order $m$ on $L^2(X)$. Assume that the semigroup $ e^{-tL}$ generated by $L$ satisfies the Davies-Gaffney estimate of order $m$ and $L$ satisfies the Plancherel type estimate. Let $H^p_L(X)$ be the Hardy space associated with $L.$ We show the boundedness of Stein's square function ${\mathcal G}_{\delta}(L)$ arising from Bochner-Riesz means associated to $L$ from Hardy spaces $H^p_L(X)$ to $L^p(X)$, and also study the boundedness of Bochner-Riesz means on Hardy spaces $H^p_L(X)$ for $0<p\leq1$.
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Since indentation rolling resistance accounts for the major part of total resistance of belt conveyor, it is important to compute it using a proper method, during the design and application study of the belt conveyor. Firstly, an ...
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Since indentation rolling resistance accounts for the major part of total resistance of belt conveyor, it is important to compute it using a proper method, during the design and application study of the belt conveyor. Firstly, an approximate formula for computing the indentation rolling resistance is offered. In this formula, a one-dimensional Winkler foundation and a three-parameter viscoelastic Maxwell solid model of the belt backing material are used to determine the resistance to motion of a conveyor belt over idlers. The velocity of belt is an important operating parameter in the working conditions of the belt conveyor. What’s more, a set of experimental apparatus, which can measure the value of indentation rolling resistance is designed. Author obtains a series of measured data under the different belt speeds with the help of experimental apparatus. Finally, a computation example, that is provided for a typical rubber compound backing material, shows the comparison between the measured and the theoretical results, which offers the influence of speed on the rolling resistance.
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In this paper, we propose a new cohesive model to stably and accurately simulate the delamination propagations in composite laminates under quasi-static and low-velocity impact transverse loads using comparatively coarse meshes. I...
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In this paper, we propose a new cohesive model to stably and accurately simulate the delamination propagations in composite laminates under quasi-static and low-velocity impact transverse loads using comparatively coarse meshes. In this model, a pre-softening zone ahead of the existing traditional softening zone is proposed. In this pre-softening zone, the initial stiffnesses and the interface strengths at the integration points of cohesive elements are gradually reduced as the corresponding effective relative displacements at these points increase. However, the onset displacement corresponding to the onset damage is not changed in this model. Moreover, the fracture toughness of materials for determining the final displacement of complete decohesion is kept constant. This cohesive model is implemented in the explicit time integration scheme combined with a powerful three-dimensional (3D) hybrid finite element for evaluating the delamination propagations on interfaces in composite laminates. A DCB problem is employed to analyze the characteristics of the present cohesive model. In order to reduce the computational cost for dealing with more complex problems, a stress-based criterion is also adopted in our numerical model for evaluating various in-plane damages, such as matrix cracks, fiber breakage, etc. Finally, two experimental examples are employed to illustrate the validity of the present approach.
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Studies conclude that breastfeeding for six months is associated with better lifelong health for the mother and the child. Mothers in the U.S. returning to work after maternity leave report difficulty with the need to take frequen...
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Studies conclude that breastfeeding for six months is associated with better lifelong health for the mother and the child. Mothers in the U.S. returning to work after maternity leave report difficulty with the need to take frequent breaks to pump breastmilk so many stop breastfeeding. Factors discouraging pumping breastmilk in the workplace motivated a content analysis of public comments posted in response to a legal deposition that occurred in January of 2011 in which an attorney who was a new mother was challenged about taking a break to pump breastmilk. A total of 899 public comments posted on Yahoo in 20152016 in response to this earlier incident were analyzed for content. Of these, only 336 mentioned breastfeeding. Overall, 148 comments showed support for breastfeeding or pumping breastmilk at work, while 182 comments showed moderate to strong disapproval (six unclassified). The majority of disapproving comments were critical of pumping breastmilk in the workplace. Implications of these findings for the duration of breastfeeding after returning to work are discussed.
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The Trematode Fasciola hepatica is an important cause of disease in livestock and in man. Modulation of immunity is a critical strategy used by this parasite to facilitate its long-term survival in the host. Understanding the unde...
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The Trematode Fasciola hepatica is an important cause of disease in livestock and in man. Modulation of immunity is a critical strategy used by this parasite to facilitate its long-term survival in the host. Understanding the underlying mechanisms at a system level is important for the development of novel control strategies, such as vaccination, as well as for increasing general understanding of helminth-mediated immunoregulation and its consequences. Our previous RNA sequencing work identified a large number of differentially expressed genes (DEG) from ovine peripheral blood mononuclear cells (PBMCs) at acute and chronic stages of F. hepatica infection, and yielded important information on host–parasite interaction, with particular reference to the immune response. To extend our understanding of the immunoregulatory effects of this parasite, we employed InnateDB to further analyze the DEG dataset and identified 2,458 and 224 molecular interactions in the context of innate immunity from the acute and chronic stages of infection, respectively. Notably, 458 interactions at the acute stage of infection were manually curated from studies involving PBMC-related cell-types, which guaranteed confident hypothesis generation. NetworkAnalyst was subsequently used to construct and visualize molecular networks. Two complementary strategies (function-first and connection-first) were conducted to interpret the networks. The function-first approach highlighted subnetworks implicated in regulation of Toll-like receptor 3/4 signaling in both acute and chronic infections. The connection-first approach highlighted regulation of intrinsic apoptosis and B-cell receptor-signaling during acute and chronic infections, respectively. To the best of our knowledge, this study is the first system level analysis of the regulation of host innate immunity during F. hepatica infection. It provides insights into the profound changes induced by F. hepatica infection that not only favors parasite survival into chronic infection but also impedes the host’s immune response to other pathogens, and render vaccination against fasciolosis a difficult challenge. The information provided will be useful in the design of specific vaccine protocols to overcome parasite-mediated immunoregulation and in furthering general understanding of the interplay between helminth infection and host immune systems.
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A prominent J wave is encountered in a number of life-threatening cardiac arrhythmia syndromes, including the Brugada syndrome and early repolarization syndromes. Brugada syndrome and early repolarization syndromes differ with res...
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A prominent J wave is encountered in a number of life-threatening cardiac arrhythmia syndromes, including the Brugada syndrome and early repolarization syndromes. Brugada syndrome and early repolarization syndromes differ with respect to the magnitude and lead location of abnormal J waves and are thought to represent a continuous spectrum of phenotypic expression termed J-wave syndromes. Despite two decades of intensive research, risk stratification and the approach to therapy of these 2 inherited cardiac arrhythmia syndromes are still undergoing rapid evolution. Our objective in this review is to provide an integrated synopsis of the clinical characteristics, risk stratifiers, and molecular, ionic, cellular, and genetic mechanisms underlying these 2 fascinating syndromes that have captured the interest and attention of the cardiology community in recent years.
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This study was conducted to compare the microbiome and metabolome differences in the colon lumen from two pig breeds with different genetic backgrounds. Fourteen weaned piglets at 30 days of age, including seven Landrace piglets (...
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This study was conducted to compare the microbiome and metabolome differences in the colon lumen from two pig breeds with different genetic backgrounds. Fourteen weaned piglets at 30 days of age, including seven Landrace piglets (a lean-type pig breed with a fast growth rate) and seven Meihua piglets (a fatty-type Chinese local pig breed with a slow growth rate), were fed the same diets for 35 days. Untargeted metabolomics analyses showed that a total of 401 metabolites differed between Landrace and Meihua. Seventy of these 401 metabolites were conclusively identified. Landrace accumulated more short-chain fatty acids (SCFAs) and secondary bile acids in the colon lumen. Moreover, expression of the SCFAs transporter (solute carrier family 5 member 8, SLC5A8) and receptor (G protein-coupled receptor 41, GPR41) in the colon mucosa was higher, while the bile acids receptor (farnesoid X receptor, FXR) had lower expression in Landrace compared to Meihua. The relative abundances of 8 genera and 16 species of bacteria differed significantly between Landrace and Meihua, and were closely related to the colonic concentrations of bile acids or SCFAs based on Pearson's correlation analysis. Collectively, our results demonstrate for the first time that there were differences in the colonic microbiome and metabolome between Meihua and Landrace piglets, with the most profound disparity in production of SCFAs and secondary bile acids.
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There has been great interest in developing a time-of-flight (TOF) PET to improve the signal-to-noise ratio of PET image relative to that of non-TOF PET. Silicon photomultiplier (SiPM) arrays have attracted attention for use as a ...
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There has been great interest in developing a time-of-flight (TOF) PET to improve the signal-to-noise ratio of PET image relative to that of non-TOF PET. Silicon photomultiplier (SiPM) arrays have attracted attention for use as a fast TOF PET photosensor. Since numerous SiPM arrays are needed to construct a modern human PET, a multiplexing method providing both good timing performance and high channel reduction capability is required to develop a SiPM-based TOF PET. The purpose of this study was to develop a capacitive multiplexing circuit for the SiPM-based TOF PET. The proposed multiplexing circuit was evaluated by measuring the coincidence resolving time (CRT) and the energy resolution as a function of the overvoltage using three different capacitor values of 15, 30, and 51 pF. A flood histogram was also obtained and quantitatively assessed. Experiments were performed using a 4×4 array of 3×3 mm2 SiPMs. Regarding the capacitor values, the multiplexing circuit using a smaller capacitor value showed the best timing performance. On the other hand, the energy resolution and flood histogram quality of the multiplexing circuit deteriorated as the capacitor value became smaller. The proposed circuit was able to achieve a CRT of 260±4 ps FWHM and an energy resolution of 17.1% with a pair of 2×2×20 mm3 LYSO crystals using a capacitor value of 30 pF at an overvoltage of 3.0 V. It was also possible to clearly resolve a 6×6 array of LYSO crystals in the flood histogram using the multiplexing circuit. The experiment results indicate that the proposed capacitive multiplexing circuit is useful to obtain an excellent timing performance and a crystalresolving capability in the flood histogram with a minimal degradation of the energy resolution, as well as to reduce the number of the readout channels of the SiPM-based TOF PET detector.
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The airway vagal preganglionic neurons (AVPNs) in the external formation of the nucleus ambiguus (eNA) play a major role in the vagal control of tracheobronchial smooth muscle tone and maintenance of airway resistance. The eNA rec...
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The airway vagal preganglionic neurons (AVPNs) in the external formation of the nucleus ambiguus (eNA) play a major role in the vagal control of tracheobronchial smooth muscle tone and maintenance of airway resistance. The eNA receives vasopressinergic projection from the hypothalamic paraventricular nucleus (PVN), the key node for the genesis of psychological stress. Since airway vagal excitation is reportedly to be associated with the psychological stress-induced/exacerbated airway hyperresponsiveness in asthmatics, arginine vasopressin (AVP) might be involved in stress-related airway vagal excitation. However, this possibility has not been validated. This study aimed to test whether and how AVP regulates AVPNs. In rhythmically active medullary slices of newborn rats, retrogradely labeled AVPNs were identified as inspiratory-activated and inspiratory-inhibited AVPNs (IA- and II-AVPNs) using patch-clamp techniques according to their inspiratory-related firing behavior and synaptic activities. The results show that under current clamp, AVP depolarized both IA- and II-AVPNs, and significantly increased their spontaneous firing rate. Under voltage clamp, AVP elicited a slow inward current, and significantly increased the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in both types of AVPNs. In addition, AVP significantly enhanced the phase-locked excitatory inspiratory inward current in inspiratory-activated airway vagal preganglionic neurons (IA-AVPNs), but significantly suppressed the phase-locked inhibitory inspiratory outward current in II-AVPNs. In both types AVPNs, AVP significantly increased the frequency and amplitude of pharmacologically isolated spontaneous GABAergic and glycinergic inhibitory postsynaptic currents (IPSCs). All of the AVP-induced effects were prevented by SR49059, an antagonist of V1a receptors, but unaffected by SSR149415, an antagonist of V1b receptors. AVP did not cause significant changes in the miniature excitatory postsynaptic currents (mEPSCs), miniature inhibitory postsynaptic currents (mIPSCs) and membrane input resistance of either type of AVPNs. These results demonstrate that AVP, via activation of V1a receptors, enhanced the spontaneous excitatory and inhibitory inputs similarly in the two types of AVPNs, but differentially altered their phase-locked inspiratory excitatory and inhibitory inputs. The overall effects of AVP are excitatory in both types AVPNs. These results suggest that increased central AVP release may be involved in the stress-induced augmentation of airway vagal activity, and, consequently, the induction or exacerbation of some airway diseases.
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