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Preoperative pneumonia in children with CHD may lead to longer stays in the ICU after surgery. However, research on the associated risk factors is limited. This study aims to evaluate the pre-, intra-, and postoperative risk factors contributing to extended ICU stays in these children.
Methods:
This retrospective cohort study collected data from 496 children with CHD complicated by preoperative pneumonia who underwent cardiac surgery following medical treatment at a single centre from 2017 to 2022. We compared the clinical outcomes of patients with varying ICU stays and utilised multivariate logistic regression analysis and multiple linear regression analyses to evaluate the risk factors for prolonged ICU stays.
Results:
The median ICU stay for the 496 children was 7 days. Bacterial infection, severe pneumonia, and Risk Adjustment for Congenital Heart Surgery-1 were independent risk factors for prolonged ICU stays following cardiac surgery (P < 0.05).
Conclusion:
CHD complicated by pneumonia presents a significant treatment challenge. Better identification of the risk factors associated with long-term postoperative ICU stays in these children, along with timely diagnosis and treatment of respiratory infections in high-risk populations, can effectively reduce ICU stays and improve resource utilisation.
Continuum robot has become a research hotspot due to its excellent dexterity, flexibility and applicability to constrained environments. However, the effective, secure and accurate path planning for the continuum robot remains a challenging issue, for that it is difficult to choose a suitable inverse kinematics solution due to its redundancy in the confined environment. This paper presents a collision-free path planning method based on the improved artificial potential field (APF) for the cable-driven continuum robot, in which the beetle antennae search algorithm is adopted to deal with the optimal problem of APF without the necessary for velocity kinematics. In addition, the local optimum problem of traditional APF is solved by the randomness of the antennae’s direction vector which can make the algorithm easily jump out of local minima. The simulation and experimental results verify the efficiency of the proposed path planning method.
The instability characteristic of a viscoelastic jet in a co-flowing gas stream is studied comprehensively. The important role of the non-uniform basic velocity in the instability analysis of viscoelastic jets is clarified, which first induces an unrelaxed elastic tension, and then produces a coupling term between the elastic tension and perturbation velocity. The elastic tension promotes the instability of the jet, while the coupling term exhibits a stabilizing effect, which is essentially related to the nonlinear constitutive relation of viscoelastic fluids and the non-uniform basic velocity. The competition between these two factors leads to the non-monotonic effect of fluid elasticity on the disturbance growth rate, which can be divided into two different regimes characterized by the Weissenberg number with values smaller or larger than unity. In different regimes, the structure of the eigenspectrum is also significantly different. Furthermore, three instability mechanisms are identified using the energy budget analysis, corresponding to the predominance of the surface tension, elastic tension and shear and pressure of the external gas, respectively. By analysing the variations of the growth rate and phase speed of the disturbances, the general features of viscoelastic jet instability are obtained. Finally, the transitions of instability modes in parameter spaces are investigated theoretically and the transition boundaries among them are provided. This study provides guidance for understanding the underlying mechanism of instability of a viscoelastic jet surrounded by a co-flowing gas stream and the transition criterion of different instability modes.
The Harihada–Chegendalai ophiolitic mélange, which is located between the Bainaimiao arc and the North China Craton, holds significant clues regarding the tectonic setting of the southern margin of the Central Asian Orogenic Belt. The ophiolitic mélange is mainly composed of gabbroic and serpentinized ultramafic rocks. Here, zircon U–Pb dating, in situ zircon Hf isotopic, whole-rock geochemical and in situ mineral chemical data from the ophiolitic mélange are reported. The zircons in the gabbroic rocks yielded concordia U–Pb ages of 450–448 Ma and exhibited slightly positive ϵHf(t) values (0.87–4.34). The geochemical characteristics of the gabbroic rocks indicate that they were generated from a mantle wedge metasomatized by subduction-derived melts from sediments with continental crust contamination, in a fore-arc tectonic setting. These rocks also experienced the accumulation of plagioclase. The geochemical characteristics of the ultramafic rocks and their Cr-spinels indicate that they may constitute part of residual mantle that has experienced a high degree of partial melting and has interacted with fluids/melts released from the subducted slab in the same fore-arc tectonic setting. The ophiolitic mélange may therefore have formed in this fore-arc tectonic setting, resulting from the northward subduction of the South Bainaimiao Ocean beneath the Bainaimiao arc during Late Ordovician time, prior to the collision between the Bainaimiao arc and the North China Craton during the Silurian to Carboniferous periods.
This paper investigates the steady coherent solutions, bifurcated from the linear stability of a stationary flow, in two-dimensional (2-D) penetrative convection. The results show that the thickness of the upper stably stratified layer, which is measured by $\theta _M$ (the dimensionless temperature at which the density is maximal, with $0\le \theta _M\le 1$), plays an important role in the linear and nonlinear dynamics. First, we investigate steady solutions of fixed aspect ratio $L=2{\rm \pi} /\alpha _c$ (where $\alpha _c$ is the critical wavenumber). The results show that the instability is supercritical when $\theta _M<0.4$ and is subcritical when $\theta _M>0.4$. When $\theta _M>0.4$, the results show that the type of solution depends on the Prandtl number ($Pr$). For instance, when $Pr\lesssim 2.4$ at $\theta _M=0.5$, the solution in one type of pair of convection cells does not exist, as the Rayleigh number $Ra$ exceeds a critical value due to a saddle-node bifurcation. When $Pr>2.4$, steady solutions can be found up to $Ra=10^{8}$ for all $\theta _M$, which exhibit the scaling of heat transfer (characterized by the Nusselt number $Nu$): $Nu\sim Ra^{1/4}$. Then, the optimal 2-D steady solutions are tracked up to $Ra=10^{9}$ by varying the aspect ratio $L$, which shows that heat transfer roughly follows the $Nu\sim Ra^{\gamma }$ ($\gamma \approx 1/3$) scaling in the regime of $10^{7}< Ra<10^{9}$. It is interesting that the optimal temperature field has an arm-like horizontal structure when $Pr<10$, while it has no significant horizontal structures when $Pr>10$. Thus, the mean temperature in the mixing region is higher at large $Pr$. The steady solutions show that $Nu\sim Pr^{-1/12}$ for $\theta _M=0$ in a certain range of $Pr$ by fixing the Rayleigh numbers, e.g. $1< Pr<10$ for 2-D optimal steady solutions at $Ra=10^{8}$ and $2< Pr<30$ for 2-D steady solutions of fixed aspect ratio at $Ra=10^{7}$. But when the Prandtl number is large or the upper stably stratified layer is thick, both the steady solutions of fixed aspect ratio and the 2-D optimal steady solutions are very weakly dependent on $Pr$.
We studied the electrokinetic flow of viscoelastic fluids subjected to an oscillatory pressure gradient. Under the assumption of laminar unidirectional flow, the constitutive and motion equations of fluids are in the linear regime. Since the surface potentials are assumed to be small, the Poisson–Boltzmann equation is linearised. Resonance behaviours appear in the flow when the elastic effect of fluids is dominant. Based on the interaction of viscoelastic shear waves, we explain the mechanism of resonance and derive the critical Deborah number, Dec = 1/4, which dictates the occurrence of resonance. Using the Maxwell fluid model, the resonance enhances the electrokinetic effects and dramatically increases the electrokinetic energy conversion efficiency. However, by employing the Oldroyd-B fluid model, we reveal that the amplification of efficiency is suppressed even for a very small Newtonian solvent contribution. This could be one of the reasons for the unavailability of reports on experimental verification regarding the high efficiency predicted by Bandopadhyay & Chakraborty (Appl. Phys. Lett., vol. 101, 2012, 043905). The damping effect of solvent viscosity is more significant for higher-order resonances. The effects of multiple relaxation times on the resonance behaviours are investigated and the results indicate that Dec still dominates the occurrence of resonances for streaming potential field and flow rate.
The soft actuator is made of superelastic material and embedded flexible material. In this paper, a kind of soft tube was designed and used to assemble two kinds of pneumatic soft actuators. The experiment and finite element analysis are used to comprehensively analyze and describe the bending, elongation, and torsion deformation of the soft actuator. The results show that the two soft actuators have the best actuation performance when the inner diameter of the soft tube is 4 mm. In addition, when the twisting pitch of the torsional actuator is 24 mm, its torsional performance is optimized. Finally, a device that can be used in the production line was assembled by utilizing those soft actuators, and some operation tasks were completed. This experiment provides some insights for the development of soft actuators with more complex motions in the future.
The hygiene hypothesis posits that the decreased incidence of parasitic infection in developed countries may underlie an increased prevalence of allergic and autoimmune diseases in these countries. As unique inflammation modulator of intracellular parasitism, Trichinella spiralis, or its excretory–secretory (ES) product, shows improved responses to allergies, autoimmune diseases, inflammatory bowel disease, type 1 diabetes, rheumatic arthritis and autoimmune encephalomyelitis by exerting immunomodulatory effects on both innate and adaptive immune cells in animal models. Research has shown that T. spiralis differs from other helminths in manipulation of the host immune response not only by well-known characteristics of its life cycle, but also by its inflammation modulation pathway. How the parasite achieves inflammation modulation has not been fully elucidated yet. This review will generalize the mechanism and focuses on ES immunomodulatory molecules of T. spiralis that may be important for developing new therapeutics for inflammatory disorders.
The Wulian complex is located on the northern margin of the Sulu orogenic belt, and was formed by collision between the North China Craton (NCC) to the north and South China Craton (SCC) to the south. It consists of the metasedimentary Wulian Group, gneissic granite and meta-diorite. The U–Pb analyses for the detrital zircons from the Wulian Group exhibit one predominant age population of 2600–2400 Ma with a peak at c. 2.5 Ga and several secondary age populations of > 3000, 3000–2800, 2800–2600, 2200–2000, 1900–1800, 1500–1300 and 1250–950 Ma; some metamorphic zircons have metamorphic ages of c. 2.7, 2.55–2.45, 2.1–2.0 and 1.95–1.80 Ga, which are consistent with magmatic-metamorphic events in the SCC. Additionally, the Wulian Group was intruded by the gneissic granite and meta-diorite at c. 0.76 Ga, attributed to Neoproterozoic syn-rifting bimodal magmatic activity in the SCC and derived from partial melting of Archaean continental crust and depleted mantle, respectively. The Wulian Group therefore has tectonic affinity to the SCC and was mainly sourced from the SCC. The detrital zircons have positive and negative ϵHf(t) values, indicating that their source rocks were derived from reworking of both ancient and juvenile crustal rocks. The major early Precambrian crustal growth took place during c. 3.4–2.5 Ga with a dominant peak at 2.96 Ga and several secondary peaks at 3.27, 2.74 and 2.52 Ga. The two oldest zircons with ages of 3307 and 3347 Ma record the recycling of ancient continental crust (> 3.35 Ga) and crustal growth prior to c. 3.95 Ga in the SCC.
The rhoptry kinase 18 of Toxoplasma gondii (TgROP18) has been identified as a key virulence factor that allows the parasite to escape from host immune defences and promotes its proliferation in host cells. Although much research is focused on the interaction between host cells and TgROP18, the development of monoclonal antibodies (mAbs) against TgROP18 has not been reported till date. To produce mAbs targeting TgROP18, two hybridomas secreting mAbs against TgROP18, designated as A1 and T2, were generated using cell fusion technology. The subtypes of the A1 and T2 mAbs were identified as IgG3 λ and IgM κ, and peptide scanning revealed that the core sequences of the antigenic epitopes were 180LRAQRRRSELVFE192 and 351NYFLLMMRAEADM363, respectively. The T2 mAb specifically reacted with both T. gondii type I and Chinese I, but not with T. gondii type II, Plasmodium falciparum or Schistosoma japonicum. Finally, the sequences of heavy chain and light chain complementarity-determining regions of T2 were amplified, cloned and characterized, making the modification of the mAb feasible in the future. The development of mAbs against TgROP18 would aid the investigation of the molecular mechanisms underlying the modulation of host cellular functions by TgROP18, and in the development of strategies to diagnose and treat Toxoplasmosis.
Seasonal influenza virus epidemics have a major impact on healthcare systems. Data on population susceptibility to emerging influenza virus strains during the interepidemic period can guide planning for resource allocation of an upcoming influenza season. This study sought to assess the population susceptibility to representative emerging influenza virus strains collected during the interepidemic period. The microneutralisation antibody titers (MN titers) of a human serum panel against representative emerging influenza strains collected during the interepidemic period before the 2018/2019 winter influenza season (H1N1-inter and H3N2-inter) were compared with those against influenza strains representative of previous epidemics (H1N1-pre and H3N2-pre). A multifaceted approach, incorporating both genetic and antigenic data, was used in selecting these representative influenza virus strains for the MN assay. A significantly higher proportion of individuals had a ⩾four-fold reduction in MN titers between H1N1-inter and H1N1-pre than that between H3N2-inter and H3N2-pre (28.5% (127/445) vs. 4.9% (22/445), P < 0.001). The geometric mean titer (GMT) of H1N1-inter was significantly lower than that of H1N1-pre (381 (95% CI 339–428) vs. 713 (95% CI 641–792), P < 0.001), while there was no significant difference in the GMT between H3N2-inter and H3N2-pre. Since A(H1N1) predominated the 2018–2019 winter influenza epidemic, our results corroborated the epidemic subtype.
Based on the Onsager reciprocal relation in the linear response regime, we first clarify the equivalence of thermodynamic and electric circuit analyses for electrokinetic energy conversion. Then we present a streaming-potential-based nanofluidic energy conversion system which comprises two immiscible fluids that form a flat interface in a slit-like channel. The validity of the Onsager reciprocal relation to such a two-fluid system is verified. The performance of such an energy converter is illustrated by considering two concrete oil–water systems with different properties. In both cases, we predict that the binary system with a thin oil layer increases both the maximum output power and the energy conversion efficiency, and this enhancement depends strongly on the mobile charges present at the oil–water interface, the salt concentration and the interface location. Concretely, for negatively charged interfaces, we find that the optimal efficiency increases with the interfacial charge for relatively thin oil layers; while for relatively thick oil layers, the interfacial charge has the opposite effect (i.e. reduction effect) on the energy conversion efficiency in the ranges of the parameters. We further investigate these systems from the viewpoint of energy transfer by deriving the related energy equation. We find that viscous dissipation consumes most of the power (more than 90 %), in both single-phase and two-fluid flows. However, the ratio of the viscous dissipation to the power input decreases with increase of the interfacial charge density for the case of a relatively thin oil layer in two-fluid flows. Meanwhile, although the presence of interfacial charges can lead to an increase in electrical dissipation, the amount of the increased power consumption is less than that of the reduced viscous dissipation in the case of a thin oil layer. Therefore, for two-fluid energy converters, the total power consumption can be reduced and the efficiency is improved.
The Tarim river basin, a river system formed by the convergence of nine tributaries, is the most heavily glacierized watershed in arid northwest China. In the basin, there are 11 665 glaciers with a total area of 19 878 km2 and a volume of 2313 km3. Glaciers in the basin play a significant role in the water resource system. It is estimated that they provide about 133 x 108 m3 of meltwater annually, contributing 39% of the total river runoff. Under the influence of global warming, northwest China has experienced a generally warmer and drier climate since the mid-19th century. However, a so-called ‘warm and wet transition’ has occurred since the late 1980s, evidenced by an increase in both precipitation and stream discharge in the Xinjiang Autonomous Region and neighboring regions. This paper describes how glaciers in the Tarim river basin have responded to such warming and increased precipitation, and the impact of these glacier changes. We analyzed the variations of more than 3000 glaciers since the 1960s using topographical maps, high-resolution satellite images and aerial photographs of the river basin. Our results indicate that glaciers in the basin have been mostly in retreat in the past 40 years, and ice wastage has significantly influenced water resources in the Tarim river basin. Estimation by a degree-day meltwater model shows the positive anomaly in stream runoff of the Tailan river can be partly attributed to the increase in glacier runoff (amounting to one-third of the stream discharge), and a rough estimation using observed average ablation on the termini of 15 glaciers in China verifies that the mass loss calculated by a glacier area-volume relation is reasonable.
The present research focuses on glacier changes in the southeast of the Qinghai–Xizang (Tibetan) Plateau, where most of the temperate glaciers in China are located. Our results show that the 102 measured glaciers in the region have all retreated between 1915 and 1980, with total area and volume decreases of 47.9 km2 and 6.95 km3, respectively. The extrapolated mass loss of all glaciers in the Gangrigabu mountains amounted to 27 km3, 9.8% of the ice mass in 1915. Between 1980 and 2001, glaciers in the region have also experienced a general retreat; however, up to 40% of the glaciers were advancing. Our analysis demonstrates that precipitation in the studied area has increased substantially since the mid-1980s. This precipitation increase is likely to bring about a positive mass balance for glaciers in the region, so that the retreat of retreating glaciers might slow down or even turn into advance. Considering the sensitivity of the temperate glaciers in the region and the uncertainty in climate projections, more attention must be paid to glacier changes in the southeast Tibetan Plateau region.
Two transmission curved crystal spectrometers are designed to measure the hard x-ray emission in the laser fusion experiment of Compton radiography of implosion target on ShenGuang-III laser facility in China. Cylindrically curved ${\it\alpha}$-quartz (10–11) crystals with curvature radii of 150 and 300 mm are used to cover spectral ranges of 10–56 and 17–100 keV, respectively. The distance between the crystal and the x-ray source can be changed over a broad distance from 200 to 1500 mm. The optical design, including the integral reflectivity of the curved crystal, the sensitivity, and the spectral resolution of the spectrometers, is discussed. We also provide mechanic design details and experimental results using a Mo anode x-ray source. High-quality spectra were obtained. We confirmed that the spectral resolution can be improved by increasing the working distance, which is the distance between the recording medium and the Rowland circle.
Hypoxia inducible factor 1 (HIF-1) is a key transcriptional factor activated during cerebral ischemia, which regulates a great number of downstream genes, including those associated with cell death. In the present study, we aimed to test the hypothesis that post-ischemic HIF-1α up-regulation might promote autophagy activation; thereby, HIF-1α inhibitor 2ME2 might prevent neurons from ischemic injury through inhibiting autophagy.
Methods:
Global ischemia was induced using the four-vessel occlusion model (4-VO) in Sprague-Dawley rats (male, 250-280g). 2-Methoxyestradiol (2ME2, 5mg/kg, i.p.) was administrated to down-regulate HIF-1α expression. Post-ischemic beclin-1 and LC3 protein expression was determined at different time points through Western blot assay. Neuronal injury was determined by cresyl violet staining and TUNEL staining in coronal histological sections.
Results:
The expression of beclin-1 and the ratio of LC3-II/LC3-I increased significantly at 12 and 24 h after ischemia. 2ME2 could remarkably inhibit the up-regulation of beclin-1 and the increase of LC3-II/LC3-I ratio during reperfusion. Moreover, 2ME2 and 3-MA exhibited powerful protective effects against ischemic/reperfusion induced neuronal injury.
Conclusions:
This study confirmed that autophagy participated in post-ischemic neuronal injury. 2ME2, a HIF-1α inhibitor, might significantly decrease autophagy activation after cerebral ischemia and relieve post-ischemic neuronal injury. Our findings demonstrate that autophagy could be a potential target for neuronal protection after cerebral ischemia.
xPb(Yb1/2Nb1/2)O3-(1 − x)Pb(Zr0.36Ti0.64)O3 (xPYN-(1 − x)PZT) piezoelectric ceramics were prepared by the conventional ceramic processing via a B-site oxide mixing route. The synthesized xPYN-(1 − x)PZT ceramics exhibit majority of perovskite structure with slight content of impurity, which exhibit typical tetragonal structure with slight orthorhombic distortion depending on compositions. All the xPYN-(1 − x)PZT ceramics exhibit high Curie temperature (TC/Tm), higher than 380 °C, and their dielectric behavior above TC/Tm can be fitted well by the Curie-Weiss law. The xPYN-(1 − x)PZT ceramics exhibit large resistivity, and excellent ferroelectric and piezoelectric properties, which provide promising for the high-power and high-temperature piezoelectric applications. However, electric energy density of the xPYN-(1 − x)PZT ceramics is small due to their nearly rectangular shape of polarization-electric field (P-E) hysteresis loop and early electric displacement saturation, which is not suitable for high energy and power storage applications.
Toxoplasma gondii is a major cause of congenital brain disease; however, the underlying mechanism of neuropathogenesis in brain toxoplasmosis remains elusive. To explore the role of T. gondii in the development of neural stem cells (NSCs), NSCs were isolated from GD14 embryos of ICR mice and were co-cultured with tachyzoites of T. gondii RH strain. We found that apoptosis levels of the NSCs co-cultured with 1×106 RH tachyzoites for 24 and 48 h significantly increased in a dose-dependent manner, as compared with the control. Western blotting analysis displayed that the protein level of C/EBP homologous protein (CHOP) was up-regulated, and caspase-12 and c-Jun N-terminal kinase (JNK) were activated in the NSCs co-cultured with the parasites. Pretreatment with endoplasmic reticulum stress (ERS) inhibitor (TUDCA) and caspase-12 inhibitor (Z-ATAD-FMK) inhibited the expression or activation of the key molecules involved in the ERS-mediated apoptotic pathway, and subsequently decreased the apoptosis levels of the NSCs induced by the T. gondii. The findings here highlight that T. gondii induced apoptosis of the NSCs through the ERS signal pathway via activation of CHOP, caspase-12 and JNK, which may constitute a potential molecular mechanism responsible for the cognitive disturbance in neurological disorders of T. gondii.
We prove that any surjective isometry between unit spheres of the ${\ell }^{\infty } $-sum of strictly convex normed spaces can be extended to a linear isometry on the whole space, and we solve the isometric extension problem affirmatively in this case.
Yellow-emitting long afterglow phosphors Sr3−xSiO5, xMF2: Eu2+, Dy3+ (0 ≤ x ≤ 0.15, M: Ba, Sr, Ca) have been prepared by high-temperature solid-state reaction method followed with rapid cooling process. Photoluminescence measurement reveals that the main emission of the phosphors locates at 575 nm, corresponding to the 4f65d1–4f7 transition of Eu2+. The introduction of alkaline earth metal fluoride effectively enhances the luminescence intensity and prolongs the afterglow time. Especially, the afterglow of the Sr2.95SiO5, 0.05BaF2: Eu2+, Dy3+ phosphor can last for 12 h. Thermal luminescence measurement shows that the trap density of Sr3SiO5: Eu2+, Dy3+ phosphor can be adjusted by adding different alkaline earth metal fluorides, which offers a feasible way to improve the afterglow properties of silicate phosphors.