Adaptive Order WENO Reconstructions for the Semi-Lagrangian Finite Difference Scheme for Advection Problem

We present a new conservative semi-Lagrangian finite difference weighted essentially non-oscillatory scheme with adaptive order. This is an extension of the conservative semi-Lagrangian (SL) finite difference WENO scheme in [Qiu and Shu, JCP, 230 (4) (2011), pp. 863-889], in which linear weights in SL WENO framework were shown not to exist for variable coefficient problems. Hence, the order of accuracy is not optimal from reconstruction stencils. In this paper, we incorporate a recent WENO adaptive order (AO) technique [Balsara et al., JCP, 326 (2016), pp. 780-804] to the SL WENO framework. The new scheme can achieve an optimal high order of accuracy, while maintaining the properties of mass conservation and non-oscillatory capture of solutions from the original SL WENO. The positivity-preserving limiter is further applied to ensure the positivity of solutions. Finally, the scheme is applied to high dimensional problems by a fourth-order dimensional splitting. We demonstrate the effectiveness of the new scheme by extensive numerical tests on linear advection equations, the Vlasov-Poisson system, the guiding center Vlasov model as well as the incompressible Euler equations.     

The Effect of a PEEK Material‐Based External Fixator in the Treatment of Distal Radius Fractures with Non‐Transarticular External Fixation

ObjectiveTo explore the effect of a PEEK material‐based external fixator in the treatment of distal radius fractures with non‐transarticular external fixation.MethodsThere were 48 patients in this prospective comparative study. They were divided into two groups according to the materials used: the PEEK group and the titanium group. Wrist dorsiflexion, palmar flexion, pronation, supination, radial deviation, ulnar deviation, grip strength of the palm on the affected side, kneading force, Visual Analogue Scale/Score (VAS), Disabilities of the Arm, Shoulder, and Hand (DASH) score, operation time, frequency of fluoroscopy procedures, and X‐ray results were compared between the two groups. Functional recovery was evaluated at the last follow‐up according to the wrist joint evaluation criteria.ResultsThe baseline data were comparable between the two groups, and no significant differences were found in age, sex, fracture types (P > 0.05). There was no significant difference between the two groups in the results of DASH, grip strength, and recovery of pinch force and wrist function (dorsiflexion, clavicle, ulnar deviation, deviation, pronation, and supination) (P > 0.05). Normal limb function was achieved in the two groups of patients at an average of 6 weeks after surgery, and there was no significant difference in X‐ray examination radial height (10.60 ± 1.59 vs 11.00 ± 1.53, P = 0.687), radial inclination (1.11 ± 0.24 vs 1.12 ± 0.24, P = 0.798), volar tilt (10.33 ± 2.13 vs 10.00 ± 2.08, P = 0.660), ulnar variance (20.87 ± 3.00 vs 20.38 ± 3.04, P = 0.748), and step‐off persistence (1.73 ± 0.69 vs 1.68 ± 0.72, P = 0.425) between the two groups (P > 0.05). However, the operation time (54.80 ± 12.20 vs 85.23 ± 15.14, P = 0.033) and number of fluoroscopy procedures (36.93 ± 6.89 vs 64.77 ± 9.74, P = 0.000) in the PEEK group were significantly reduced compared with those in the titanium group.ConclusionCompared with the traditional titanium external fixator, the PEEK composite external fixator has advantages, such as a shorter operation time and fewer fluoroscopy procedures when used to treat different types of distal radius fracture.     

Novel glucose-lowering drugs for non-alcoholic fatty liver disease

BACKGROUNDThe efficacy of novel glucose-lowering drugs in treating non-alcoholic fatty liver disease (NAFLD) is unknown.AIMTo evaluate the efficacy of glucose-lowering drugs dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1 RAs), and sodium-glucose cotransporter 2 (SGLT2) inhibitors in treating NAFLD and to perform a comparison between these treatments.METHODSElectronic databases were systematically searched. The inclusion criteria were: Randomized controlled trials comparing DPP-4 inhibitors, GLP-1 RAs, or SGLT2 inhibitors against placebo or other active glucose-lowering drugs in NAFLD patients, with outcomes of changes in liver enzyme [alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST)] from baseline.RESULTSNineteen studies were finally included in this meta-analysis. Compared with placebo or other active glucose-lowering drug treatment, treatment with DPP-4 inhibitors, GLP-1 RAs, and SGLT2 inhibitors all led to a significant decrease in ALT change and AST change from baseline. The difference between the DPP-4 inhibitor and SGLT2 inhibitor groups in ALT change was significant in favor of DPP-4 inhibitor treatment (P < 0.05). The trends of reduction in magnetic resonance imaging proton density fat fraction and visceral fat area changes were also observed in all the novel glucose-lowering agent treatment groups.CONCLUSIONTreatment with DPP-4 inhibitors, GLP-1 RAs, and SGLT2 inhibitors resulted in improvements in serum ALT and AST levels and body fat composition, indicating a beneficial effect in improving liver injury and reducing liver fat in NAFLD patients.     

新型冠状病毒Delta变异株引起的广州市荔湾区本土疫情流行特征分析

目的 分析新型冠状病毒（新冠病毒）B.1.617.2（Delta）变异株引起的广州市荔湾区本土疫情流行特征,为Delta变异株疫情防控工作提供参考依据。方法 资料来源于中国疾病预防控制信息系统传染病报告信息管理系统和广州市荔湾区CDC,收集2021年5月21日至6月18日广州市荔湾区新冠病毒感染者（确诊病例和无症状感染者）相关信息。采用频数（构成比）、直方图、百分比堆积面积图等对本次Delta变异株疫情的流行病学特征进行描述,并应用潜伏期、动态再生系数（R_t）估计进行分析。结果 截至6月18日广州市荔湾区累计报告新冠病毒感染者127例,年龄范围2~85岁,<18、18~59和≥60岁年龄组分别占18.9%（24/127）、43.3%（55/127）和37.8%（48/127）。男女性别比为1：1.35（54：73）;职业以离退休人员32.3%（41/127）、家务及待业18.1%（23/127）和学生16.5%（21/127）为主;主要集中在荔湾区的白鹤洞街道（70.1%,89/127）与中南街道（23.6%,30/127）;Delta变异株的中位潜伏期6（范围：1~15）d;临床分型以普通型（64.6%,82/127）为主;基本再生系数（R₀）=5.1,R_t先上升后下降,最高达7.3;传播方式以密闭空间为主,具有明显的家庭聚集性,主要传播场所为家庭（26.8%,34/127）、餐馆（29.1%,37/127）、小区（3.9%,5/127）和市场（3.1%,4/127）。密切接触者筛查（66.1%）和社区排查（33.1%）是发现感染者的主要途径。结论 本次疫情新冠病毒Delta变异株的传染性较强,广州市荔湾区本土疫情具有明显的家庭聚集性,新冠病毒感染者以18~59和≥60岁年龄组为主。     

三层式nCHAC/PLGA复合膜体外降解行为的研究

目的探讨引导组织再生性复合膜-纳米碳羟磷灰石/胶原/聚乳酸羟基乙酸复合膜(nCHAC/PLGA) 在体外的生物降解行为。方法根据牙周治疗的特点,功能分级材料nCHAC/PLGA膜制备成三层,即8wt％ nCHAC PLGA/4wt％nCHAC PLGA/PLGA。其中一面为多孔结构,利于细胞在其上生长;另一面表面光滑,籍此抑制细胞的粘附。以纯聚乳酸羟基乙酸(PLGA)膜作为对照,将样本浸泡在37℃人工唾液中,比较两者生物降解行为。结果膜重量持续减轻,nCHAC/PLGA三层式功能分级复合膜在4周后重量减少23．1％, 12周后减少88％;单层纯聚乳酸羟基乙酸膜在4周后重量减轻30．7％,12周后减轻98．9％。处理4周后,因纳米碳羟磷灰石的降解,介质中钙离子浓度显著增加。另外,浸泡nCHAC/PLGA膜的溶液pH值略高于浸泡纯PLGA膜者,提示nCHAC复合物可能对溶液中PLGA酸性产物具中和作用。实验过程中,测试样本整体原形能维持4周,8周和12周时变成粉末状。扫描电镜结果显示,随着浸泡时间延长,膜的8wt％ nCHAC PLGA多孔疏松面增加,PLGA致密光滑面亦出现小孔结构。结论复合膜的降解过程符合牙周修复的实际过程;此外,复合膜表面形成新的矿物结构,将对体内新骨再生起积极效应。     

γ干扰素cDNA在胃癌细胞中的表达研究

实验用构建的正向连入人ＩＦＮ－γｃＤＮＡ片段的重组表达载体ｐＭＡＭｎｅｏ－γ－ＩＦＮ，以Ｌｉｐｏ－ｆｅｃｔｉｎ介导法将重组载体转染入胃癌细胞７９０１中，挑选出Ｇ４１８抗性克隆，地塞米松诱导其分泌ＩＦｔＩ－γ经活性测定筛选出高分泌ＩＦＮ－γ的细胞株ＲＰＭ７９０１－７（１７２５ＩＵ／ｍｌ），Ｓｏｕｔｈｅｒｎｂｌｏｔ证实ＩＦＮ－γｃＤＮＡ确已导入该细胞株中。体外培养过程中，ＲｐＭ７９０１细胞与转染了对照质粒ｐＭＡＭｎｅｏ的细胞ｐＭ７９０１及野生型７９０１细胞在形态，生长能力等方面无明显差别，而经地塞米松诱导的ＲpＭ７９０１细胞则与之有显著差异。裸鼠体内接种显示，经诱导的ＲｐＭ７９０１细胞在致瘤性上显著低于野生型７９０１细胞及ｐＭ７９０１细胞。经基因转移后可高分泌ＩＦＮ－γ的肿瘤细胞为肿瘤的基因治疗提供了资料。     

顺行交锁髓内钉治疗肱骨骨折

目的探讨顺行交锁髓内钉治疗肱骨骨折的手术要点和治疗效果。方法回顾性分析2003年10月～2005年10月23例顺行肱骨交锁髓内钉治疗肱骨干中上段骨折。结果全部病例随访6个月～1年3个月,平均11个月。所有病例均骨性愈合,平均临床愈合时间为2.4个月。所有关节活动度均可。结论顺行交锁髓内钉治疗肱骨中段或中上段骨折,效果良好。     

用非同位素原位杂交组化在光镜和电镜水平观察前阿黑皮素mRNA在垂体的分布

用地高辛标记反意前阿黑皮素(pro-opiomelanocortin,POMC)cRNA探针原位杂交组化在光镜和电镜水平观察了POMC mRNA在大鼠垂体的分布,并比较了碱性磷酸酶(AKP)显色系统和辣根过氧化酶(HRP)显色系统在光镜水平上的敏感性.结果:POMC mRNA广泛地分布于垂体的中间叶和前叶.中间叶全部细胞均为POMC mRNA阳性.前叶中除前叶的腹侧缘和前叶与中间叶交界处阳性细胞较少外,都有较多的POMC mRNA阳性细胞分布.AKP显色系统比HRP显色系统敏感.在电镜水平,POMC mRNA主要分布于粗面内质网,少数分泌颗粒可能呈阳性反应,胞核未见阳性反应沉淀.文内还就阳性分泌颗粒在调节细胞合成功能方面可能起的作用进行了讨论.     

Antigen-specific production of interleukin (IL)-13 and IL-5 cooperate to mediate IL-4Ralpha-independent airway hyperreactivity

The pathogenesis of human asthma and the development of key features of pulmonary allergy in mouse models has been critically linked to IL-13. Analyses of the receptor components employed by IL-13 have shown that delivery of this cytokine to the airways of naive IL-4Ralpha gene targeted (IL-4Ralpha(-/-)) mice fails to induce disease, suggesting that this membrane protein is critical for transducing IL-13-mediated responses. The current study demonstrates that, in contrast to naive mice, T helper 2 bias, airways hyperreactivity (AHR) and tissue eosinophilia develop in Ovalbumin-sensitized IL-4Ralpha(-/-) mice and that these responses can be inhibited by the IL-13 antagonist sIL-13Ralpha2Fc. Therefore, antigen stimulation induces an IL-13-regulated response that is independent of IL-4Ralpha. To determine the role of IL-5 and eosinophils in the development of disease in antigen-exposed IL-4Ralpha(-/-) mice, pulmonary allergy was examined in mice deficient in both factors. IL-4Ralpha/IL-5(-/-) mice were significantly defective in their ability to produce IL-13 and failed to develop AHR, suggesting that IL-5 indirectly regulates AHR in allergic IL-4Ralpha(-/-) mice by an IL-13-dependent mechanism. Collectively, these results demonstrate that IL-13-dependent processes regulating the development of AHR and T helper bias persist in the in the lungs of allergic IL-4Ralpha(-/-) mice.