Development of a High-Resolution Scheme for Solving the PNP-NS Equations in Curved Channels

A high-order finite difference scheme has been developed to approximate the spatial derivative terms present in the unsteady Poisson-Nernst-Planck (PNP) equations and incompressible Navier-Stokes (NS) equations. Near the wall the sharp solution profiles are resolved by using the combined compact difference (CCD) scheme developed in five-point stencil. This CCD scheme has a sixth-order accuracy for the second-order derivative terms while a seventh-order accuracy for the first-order derivative terms. PNP-NS equations have been also transformed to the curvilinear coordinate system to study the effects of channel shapes on the development of electroosmotic flow. In this study, the developed scheme has been analyzed rigorously through the modified equation analysis. In addition, the developed method has been computationally verified through four problems which are amenable to their own exact solutions. The electroosmotic flow details in planar and wavy channels have been explored with the emphasis on the formation of Coulomb force. Significance of different forces resulting from the pressure gradient, diffusion and Coulomb origins on the convective electroosmotic flow motion is also investigated in detail.     

Can different physicians providing urgent and non-urgent treatment improve patient flow in emergency department?

Background

Emergency Department (ED) overcrowding is a worldwide problem, and it might be caused by prolonged patient stay in the ED. This study tried to analyze if different practice models influence patient flow in the ED.

肺癌脊椎骨转移（18）F-FDG PET/CT与MRI的对比分析

目的：比较分析18 F-FDG PET/CT与MRI在肺癌脊椎骨转移诊断方面的敏感性、特异性。方法：28例肺癌PET/CT疑脊椎转移患者行MRI检查,比较两种方法对脊椎转移的显示征象。统计学方法采用配对四格表资料2检验,P〈0.05被认为差异有显著性。结果：经病理或随访确诊脊椎骨转移22例。以受累椎体病灶个数为统计单位,脊椎范围内共700个椎体,153个为真阳性,574个为真阴性。PET/CT诊断正确143个病灶,假阴性10个,假阳性24个,其敏感性93.4%,特异性95.6%。MRI诊断正确145个病灶,假阴性8个,无假阳性,其敏感性94.7%,特异性100%。结论：在显示脊椎骨转移方面,MRI较PET/CT具有更高的敏感性、特异性。     

Anti-ageing effects of alpha-naphthoflavone on normal and UVB-irradiated human skin fibroblasts

Ageing is a complex and multifactorial process resulting in several functional and aesthetic changes to the skin. We found that α-Naphthoflavone (α-NF) concentration-dependently induced pro-collagen type I protein expression and inhibited MMP-1 protein expression, in both normal and UVB-irradiated cells. SB431542 and SIS3 - inhibitors of TGF-β and Smad3, respectively - significantly alleviate α-NF-caused response of MMP-1 and pro-collagen. LY294002 (PI3K inhibitor) can reverse α-NF-induced ERK, Akt, Smad-3 activation, pro-collagen synthesis and α-NF-suppressed AP-1 activation. PD (ERK inhibitor) was not involved in pro-collagen generation and MMP-1 inhibition. We concluded that α-NF promotes pro-collagen production and inhibits MMP-1 expression via the activation of a PI3K/Akt/Smad-3 pathway in normal and UVB-irradiated human skin fibroblasts, while TGF-β may play an important role in transducing this pathway. These results suggest that α-NF, a natural plant product, has the potential to become a novel anti-ageing skin application.     

Extraluminal Placement of a Bronchial Blocker Compared with Carbon Dioxide Artificial Pneumothorax in Infants Undergoing Video-Assisted Thoracoscopic Surgery

Objective: To investigate the safety and effectiveness of extraluminal placement of a bronchial blocker compared with carbon dioxide (CO₂) artificial pneumothorax in infants undergoing video-assisted thoracoscopic surgery (VATS).Methods: The study involved 33 infants (group A) who underwent one-lung ventilation (OLV) with extraluminal placement of a bronchial blocker and 35 other infants (group B) who underwent CO₂ artificial pneumothorax. Clinical characteristics, the degree of lung collapse, and complications were compared.Results: The degree of lung collapse in group A was significantly higher than that in group B at T2 and T3. The mean arterial pressure (MAP) of group B was significantly lower than that of group A at 10 min and 30 min after OLV. The partial pressure of carbon dioxide (PaCO₂) of group B was significantly higher than that of group A at 30 min after OLV. The incidence of hypotension in group B was higher than that in group A.Conclusion: Compared with CO₂ artificial pneumothorax, extraluminal placement of a bronchial blocker is associated with a better degree of lung collapse, fewer episodes of hypotension, and lower PaCO₂ accumulation during OLV in infants undergoing VATS.     

The role of meperidine in reduction of postanesthetic shivering and its possible impact on flap outcomes

Postoperative vascular compromise is a common but critical complication requiring emergent re‐exploration, and remains a chief cause of free flap failure. This study investigated the relationship between postanesthetic shivering (PAS) and the development of postoperative complications associated with free flap reconstruction. One hundred thirty‐six patients who underwent head and neck cancer resection and free flap reconstruction were retrospectively enrolled. Fifteen patients were assigned to the PAS group, while the others were assigned to the non‐PAS (NPAS) group. The odds ratios of acute re‐exploration or total failure of the free flap in the PAS group was 3.5 and 14.9, respectively. The dose of meperidine was positively correlated with PAS prevention in our statistical ROC curve analysis. The minimum effective dose of meperidine for PAS prevention was 0.35 mg/kg with 75% sensitivity and 60% specificity. These findings indicate that an optimal dose of meperidine could prevent PAS, which is shown to be associated with a decrease in the incidence of the early post‐surgical re‐exploration rate of these free flaps related to circulatory compromise. © 2013 Wiley Periodicals, Inc. Microsurgery 34:106–111, 2014.     

Anosmia and olfactory tract neuropathy in a case of COVID-19

Coronavirus Disease-19 (COVID-19) has been in a global pandemic currently and relating symptoms were reported variously around the world. We reported a previously healthy man of COVID-19 presenting with anosmia as the obvious symptom with relevant radiological findings on brain magnetic resonance imaging.