Parameterization of Sea Surface Drag Coefficient for All Wind Regimes Using 11 Aircraft Eddy-Covariance Measurement Databases

The drag coefficient is essential for calculating the aerodynamic friction between air and sea. In this study, we regress a set of relationships between the drag coefficient and the wind speed for different wind ranges using an observational dataset that consists of 5941 estimates of the mean flow and fluxes from 11 aircraft turbulent measurements over the sea surface. Results show that: (1) the drag coefficient is a power function of wind speed over smooth sea surface when it is no greater than 4.5 ms−1, and the drag coefficient decreases with the increase of wind speed; and (2) for rough sea surface, when the wind speed is greater than 4.5 ms−1 and less than or equal to 10.5 ms−1, the drag coefficient increases linearly with the increase of horizontal wind speed; when the wind speed is greater than 10.5 ms−1 and less than or equal to 33.5 ms−1, the drag coefficient changes parabolically with the increase of wind speed; when the wind speed is greater than 33.5 ms−1, the drag coefficient is constant. Additionally, regressed from drag coefficient, the saturated wind speed threshold is 23 ms−1. Parameterizations of turbulent heat transfer coefficient (Ch) and water vapor transfer coefficient (Ce) are also investigated

Microstructure, mechanical and corrosion properties of Mg–2Dy–xZn (x=0, 0.1, 0.5 and 1 at.%) alloys

Microstructure, mechanical and corrosion properties of as-cast Mg–2Dy-xZn (x = 0, 0.1, 0.5, and 1) (at.%) alloys were investigated. The microstructures of the as-cast Mg–2Dy and Mg–2Dy–0.1Zn alloys mainly consisted of α-Mg phase and Mg24Dy5 eutectic phase. With 0.5 at.% Zn addition, Mg12ZnDy phase with 18R-type long period stacking ordered (LPSO) structure and Mg2Dy phase precipitated at the grain boundaries. When the content of Zn is 1 at.%, only the Mg3Zn3Dy2 phase formed in the α-Mg matrix. The electrochemical measurements and immersion testing results indicated that the Mg–2Dy–0.1Zn alloy exhibited the best corrosion resistance. It revealed that the morphology, scale, amount and distribution of the second phase have a great effect on the corrosion resistance of alloy. Additionally, the tensile testing results showed that the Mg–2Dy–0.5Zn alloy exhibited the higher tensile strength and good elongation, especially at 200 °C. The improvement of mechanical properties was mainly due to the strengthening of LPSO phase and grain refinement of α-Mg

Serotonin Exhibits Accelerated Bleomycin-Induced Pulmonary Fibrosis through TPH1 Knockout Mouse Experiments

Background. Pulmonary fibrosis is a chronic progressive fibrosis interstitial lung disease that is characterized by inflammatory infiltration and fibrotic changes. 5-Hydroxytryptamine (5-HT) is an important regulatory factor in inflammation, immunomodulation, and fibrosis. The aim of this study was to investigate the role of 5-HT in bleomycin- (BLM-) induced pulmonary fibrosis through wild-type C57BL/6 (WT) and TPH1 knockout (KO) mouse experiments. Methods. The mice were grouped as follows: WT control group, KO control group, WT BLM group, and KO BLM group. Mice were administrated bleomycin hydrochloride through intratracheal instillation to induce pulmonary fibrosis. Mice were sacrificed 0, 7, 14, and 21 days after modeling, and bronchoalveolar lavage fluid (BALF) and lung tissues were collected to determine the severity of fibrotic changes. Results. The results showed that the weight loss of mice in the WT BLM group was more severe than that in the KO BLM group. H&E and Sirius Red staining revealed that 5-HT markedly aggravated histological damage and fibrotic changes in the lung. Significantly lower levels of hydroxyproline, Ashcroft fibrosis score, total BALF protein and cells, BALF tumor necrosis factor- (TNF-) α and interleukin- (IL-) 6, TNF-α and IL-6 mRNA, malondialdehyde (MDA), and myeloperoxidase- (MPO-) positive cells in the lung tissues, and fibrosis-associated proteins were discovered in the mice from the KO BLM group compared with the WT BLM group. Conclusion. 5-HT aggravated pulmonary fibrosis mainly by promoting the inflammation, exudation of proteins and cells, oxidative stress, and upregulation of fibrosis-associated genes in the lung tissues

Comparison of clinical characteristics and outcomes of pyogenic liver abscess patients < 65 years of age versus ≥ 65 years of age

Abstract Background Pyogenic liver abscess (PLA) in the elderly is insufficiently elucidated. A few studies attempted to investigate the role of age in PLA have yielded controversial results. The purpose of this study was to explore the possible differences in the comorbidity, microbiological characteristics and clinical course between elderly and young PLA patients. Methods The clinical data of 332 adult PLA patients who received treatment at our hospital from January 2010 to December 2016 were collected. The demographic data, etiologies, comorbidities, clinical features, laboratory results, imaging findings, microbiological characteristics, choices of treatment and clinical outcomes were analyzed. Results Eighty-two (24.7%) patients were older than 65 years. Comorbidities including hypertension, diabetes mellitus, and cholelithiasis were more frequently found in older patients. Elderly PLA patients were more likely to present with atypical symptoms and signs on admission. The laboratory abnormalities and imaging findings were similar between the two groups. Klebsiella pneumonia was the most common pathogen on pus culture in both groups. There were no statistically significant differences in choices of treatment, PLA-related complications and length of in-hospital stay between the two groups. And there was no in-hospital mortality. Conclusions The clinical characteristics were similar in young and elderly PLA patients. However, elderly PLA patients were more likely to have underlying diseases and tended to have atypical presentations. Physicians need to be vigilant when encounter possible elderly patients with PLA. However, older PLA patients had comparable outcomes as their younger counterparts. With effective treatment, both elderly and young PLA patients can be cured

5-HT Drives Mortality in Sepsis Induced by Cecal Ligation and Puncture in Mice

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection with a high mortality. 5-Hydroxytryptamine (5-HT) is an important regulatory factor in inflammation. The aim of this study is to investigate the role of 5-HT on cecal ligation and puncture- (CLP-) induced sepsis in the mouse model. CLP was performed on C57B/6 wild-type (WT) mice and tryptophan hydroxylase 1 (TPH1) knockout (KO) mice. The results showed that the 5-HT-sufficient group mice had a significantly lower survival rate than the 5-HT-deficient group in CLP-induced sepsis and septic shock. The KO-CLP sepsis group received a lower clinical score than the WT-CLP sepsis group. Meanwhile, the body temperature of mice in the KO-CLP sepsis group was higher than that in the WT-CLP sepsis group and was much closer to the normal body temperature 24 hours after CLP. The tissue histopathology analysis revealed that 5-HT markedly exacerbated histological damages in the peritoneum, lung, liver, kidney, intestinal tissue, and heart in sepsis. Moreover, significant lower levels of TNF-α, IL-6, bacterial loads, MPO, and ROS were discovered in the KO-CLP sepsis group in contrast to the WT-CLP sepsis group. In conclusion, 5-HT drives mortality and exacerbates organ dysfunction by promoting serum cytokines and bacterial loads as well as facilitating oxidative stress in the process of sepsis

Mutant TDP-43 in motor neurons promotes the onset and progression of ALS in rats

Amyotrophic lateral sclerosis (ALS) is characterized by progressive motor neuron degeneration, which ultimately leads to paralysis and death. Mutation of TAR DNA binding protein 43 (TDP-43) has been linked to the development of an inherited form of ALS. Existing TDP-43 transgenic animals develop a limited loss of motor neurons and therefore do not faithfully reproduce the core phenotype of ALS. Here, we report the creation of multiple lines of transgenic rats in which expression of ALS-associated mutant human TDP-43 is restricted to either motor neurons or other types of neurons and skeletal muscle and can be switched on and off. All of these rats developed progressive paralysis reminiscent of ALS when the transgene was switched on. Rats expressing mutant TDP-43 in motor neurons alone lost more spinal motor neurons than rats expressing the disease gene in varying neurons and muscle cells, although these rats all developed remarkable denervation atrophy of skeletal muscles. Intriguingly, progression of the disease was halted after transgene expression was switched off; in rats with limited loss of motor neurons, we observed a dramatic recovery of motor function, but in rats with profound loss of motor neurons, we only observed a moderate recovery of motor function. Our finding suggests that mutant TDP-43 in motor neurons is sufficient to promote the onset and progression of ALS and that motor neuron degeneration is partially reversible, at least in mutant TDP-43 transgenic rats