Comparison of acute pneumonia caused by SARS-CoV-2 and other respiratory viruses in children:a retrospective multi-center cohort study during COVID-19 outbreak

Background:Until January 18,2021,coronavirus disease-2019 (COVID-19) has infected more than 93 million individuals and has caused a certain degree of panic.Vira...     

An Evaluation of Phylogenetic Workflows in Viral Molecular Epidemiology

The use of viral sequence data to inform public health intervention has become increasingly common in the realm of epidemiology. Such methods typically utilize multiple sequence alignments and phylogenies estimated from the sequence data. Like all estimation techniques, they are error prone, yet the impacts of such imperfections on downstream epidemiological inferences are poorly understood. To address this, we executed multiple commonly used viral phylogenetic analysis workflows on simulated viral sequence data, modeling Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV), and Ebolavirus, and we computed multiple methods of accuracy, motivated by transmission-clustering techniques. For multiple sequence alignment, MAFFT consistently outperformed MUSCLE and Clustal Omega, in both accuracy and runtime. For phylogenetic inference, FastTree 2, IQ-TREE, RAxML-NG, and PhyML had similar topological accuracies, but branch lengths and pairwise distances were consistently most accurate in phylogenies inferred by RAxML-NG. However, FastTree 2 was the fastest, by orders of magnitude, and when the other tools were used to optimize branch lengths along a fixed FastTree 2 topology, the resulting phylogenies had accuracies that were indistinguishable from their original counterparts, but with a fraction of the runtime.     

Study on Morphology and Chemical States of Surface Active Layer of Th-W Cathode

The surface morphology and chemical states of W-2%ThO₂ thermionic cathode during vacuum high-temperature treatment were investigated in this research. The W-2%ThO₂ thermionic cathode was prepared by a solid-liquid doping method combined with high-temperature sintering. The morphology and distribution of thorium oxide were observed using a transmission electron microscope and scanning electron microscope. The chemical states of elements at different temperatures were analyzed by X-ray photoelectron spectroscopy. Results indicate that the surface morphology and chemical form of the alloy evolve with the increase of temperature. The matrix had a lamellar structure at low temperatures, and the surface was relatively flat. The samples were heated to 500 °C, 1100 °C, and 1300 °C for 1 h. During the heating process, thorium oxide changed from granular to spherical, and the matrix was recrystallized. As the heating temperature rises, diffusion channels appear inside the cathode. As the temperature increases, the high-priced tungsten gradually decreases, and the zero-valent tungsten content increases. The adsorbed oxygen left the cathode surface, and the lattice oxygen increased. The surface oxygen content decreased, and the thorium and tungsten content increased.     

症状前期帕金森病的PET/SPECT功能影像学研究

帕金森病(PD)是一种慢性中枢神经系统退化性病变。目前有充分的证据显示PD的特征性病理学改变在临床起病之前即可出现,即在所谓症状前期的亚临床阶段。以PET/SPECT为代表的功能影像学技术已在临床PD诊断中得到广泛应用,通过对PD患者黑质纹状体多巴胺能功能的评估,可客观、有效地对PD进行诊断及鉴别诊断。文中就PET/SPECT功能影像学技术在检测症状前期PD中的应用作一综述。     

谈提高科室主任综合能力

科室主任肩负着医院学科建设与人才培养的重任,科室主任的综合能力是医院创新能力的核心与关键,决定着医院核心竞争力的强弱,关系着医院的可持续发展。本文重点论述了如何加强科室主任自身的科学研究能力、合作交流能力与组织协调能力。     

Effects on the crystallization behavior and biocompatibility of poly(LLA-ran-PDO-ran-GA) with poly(d-lactide) as nucleating agents

The blends of poly(l-lactide acid-p-dioxanone-glycolide) (PLPG) with poly(d-lactide) (PDLA) (PLPG/PDLA) were prepared by a solution-casting method. The effects of PDLA on the properties of the PLPG were studied. DSC and WAXD results confirmed that PLA stereocomplex (sc-PLA) crystals were formed by blending PLLA segments in PLPG with PDLA, and the melting endotherm for both PLLA and sc-PLA relied on PDLA content. The non-isothermal crystallization results indicated that the crystallization process was remarkably accelerated by the addition of PDLA. Meanwhile, the results of isothermal crystallization indicated that the half-time of crystallization decreased with the increase of PDLA content. Besides, the enzymatic degradation behavior of the samples showed that with the increase of PDLA content, the mass loss gradually decreased. Furthermore, TGA and DTG results indicated that the thermal degradation of the samples was a complex process. Moreover, the biocompatibility of the samples was tested by cell culture and using CCK-8 and live/dead staining. Results showed that the samples possessed lower cytotoxicity. Therefore, the PLPG/PDLA blends are promising candidate materials in biomedical applications.

Sc-PLA crystals in the PLPG/PDLA blends were formed by hydrogen bond between PDLA and PLLA segments, which enhance the crystallization ability of PLLA in the PLPG matrix by decreasing the activation free energy.     

甲状腺内胸腺癌一例

甲状腺内胸腺癌是甲状腺肿瘤的独立病理类型,临床罕见,本文报道一例我院收治的64岁女性患者,因颈部肿块伴呼吸、吞咽困难就诊,术前穿刺结果示：伴胸腺样分化的甲状腺癌。行甲状腺左叶切除+甲状腺右叶大部切除+胸骨后甲状腺病损切除术,术后病理结果示：甲状腺内胸腺癌。术后进行放、化疗,随访6个月,患者生活质量改善。本文通过总结该病...     

Losartan attenuates bleomycin-induced pulmonary fibrosis in rats

BACKGROUND: In addition to regulating blood pressure and body fluid homeostasis, the renin-angiotensin system is also involved in lung fibrogenesis. OBJECTIVE: To study the effect of losartan, an angiotensin II antagonist, on bleomycin-induced pulmonary fibrosis in rats and its possible mechanism. METHODS: Pulmonary fibrosis was induced in SD rats by intratracheal instillation of bleomycin (5 mg x kg(-1)). Subsequently, the rats received daily losartan (3, 9 and 27 mg x kg(-1)) or prednisone (20 mg x kg(-1)) orally. Six rats in each group were sacrificed 14 and 21 days after intratracheal instillation. Hydroxyproline, superoxide dismutase (SOD), and malondialdehyde (MDA) levels in lung tissues were determined by spectroscopy. The levels of TGF-beta1 in serum were measured by ELISA. Histological changes in the lungs were evaluated by hematoxylin-eosin stain, and scored. RESULTS: Rat body weight evidently decreased while the indices of lung and hydroxyproline contents in lung tissue were significantly increased 14 and 21 days after intratracheal bleomycin instillation. Inflammatory cell infiltration and fibrotic scores were more prominent in the model group compared to the sham group. Losartan (3, 9 and 27 mg.kg(-1), i.g.) apparently attenuated the degree of pulmonary fibrosis. Further study showed that losartan significantly increased SOD levels while it decreased MDA contents in lung homogenates. Serum TGF-beta1 levels of pulmonary fibrosis rats were also decreased by losartan. CONCLUSIONS: Losartan had an inhibitory effect on bleomycin-induced pulmonary fibrosis, and its effect may be associated with its anti-free radicals and the reduction in TGF-beta1.     

Clinical and economic outcomes of a multidisciplinary team approach in a lower extremity amputation prevention programme for diabetic foot ulcer care in an Asian population: A case‐control study

Present guidelines recommend a multidisciplinary team (MDT) approach to diabetic foot ulcer (DFU) care, but relevant data from Asia are lacking. We aim to evaluate the clinical and economic outcomes of an MDT approach in a lower extremity amputation prevention programme (LEAPP) for DFU care in an Asian population. We performed a case‐control study of 84 patients with DFU between January 2017 and October 2017 (retrospective control) vs 117 patients with DFU between December 2017 and July 2018 (prospective LEAPP cohort). Comparing the clinical outcomes between the retrospective cohort and the LEAPP cohort, there was a significant decrease in mean time from referral to index clinic visit (38.6 vs 9.5 days, P < .001), increase in outpatient podiatry follow‐up (33% vs 76%, P < .001), decrease in 1‐year minor amputation rate (14% vs 3%, P = .007), and decrease in 1‐year major amputation rate (9% vs 3%, P = .05). Simulation of cost avoidance demonstrated an annualised cost avoidance of USD $1.86m (SGD $2.5m) for patients within the LEAPP cohort. In conclusion, similar to the data from Western societies, an MDT approach in an Asian population, via a LEAPP for patients with DFU, demonstrated a significant reduction in minor and major amputation rates, with annualised cost avoidance of USD $1.86m.