The influence of coronavirus disease 2019 on emergency department visits in Nanjing, China: A multicentre cross-sectional study.

INTRODUCTION: Influenza has been linked to the crowding in emergency departments (ED) across the world. The impact of the Coronavirus Disease 2019 (COVID-19) pandemic on China EDs has been quite different from those during past influenza outbreaks. Our objective was to determine if COVID-19 changed ED visit disease severity during the pandemic. METHODS: This was a retrospective cross sectional study conducted in Nanjing, China. We captured ED visit data from 28 hospitals. We then compared visit numbers from October 2019 to February 2020 for a month-to-month analysis and every February from 2017 to 2020 for a year-to-year analysis. Inter-group chi-square test and time series trend tests were performed to compare visit numbers. The primary outcome was the proportion of severe disease visits in the EDs. RESULTS: Through February 29 th 2020, there were 93 laboratory-confirmed COVID-19 patients in Nanjing, of which 40 cases (43.01%) were first seen in the ED. The total number of ED visits in Nanjing in February 2020, were dramatically decreased (n = 99,949) in compared to January 2020 (n = 313,125) and February 2019 (n = 262,503). Except for poisoning, the severe diseases in EDs all decreased in absolute number, but increased in proportion both in year-to-year and month-to-month analyses. This increase in proportional ED disease severity was greater in higher-level referral hospitals when compared year by year. CONCLUSION: The COVID-19 outbreak has been associated with decreases in ED visits in Nanjing, China, but increases in the proportion of severe ED visits.

1.2-W average-power, 700-W peak-power, 100-ps dissipative soliton resonance in a compact Er:Yb co-doped double-clad fiber laser.

Mode-locked pulses in the dissipative soliton resonance (DSR) regime enable extremely high pulse energy, but typically have the limited peak power of <100 W and a nanosecond-long pulse duration. In this Letter, we demonstrate high-peak-power, ultrashort DSR pulses in a compact Er:Yb co-doped double-clad fiber laser. The linear cavity is simply formed by two fiber loop mirrors (FLMs) using a 50/50 optical coupler (OC) and a 5/95 OC. The 5/95 FLM with a short loop length of 3 m is not only used as the output mirror, but also acts as a nonlinear optical loop mirror for initiating high-peak-power DSR. In particular, the mode-locked laser can deliver ∼100 ps DSR pulses with a maximum average power of 1.2 W and a peak power as high as ∼700 W. This is, to the best of our knowledge, the highest peak power of DSR pulses obtained in mode-locked fiber lasers.

Intermode beating mode-locking technique for a rare-earth-doped fiber pulsed laser.

In this paper, we report the intermode beating mode-locking of a 2 µm Tm3+-doped fiber laser (TDFL) pumped by a 1565 nm continuous-wave multi-longitudinal-mode laser. Because strong intermode beating of the 1565 nm pump source induces the periodic modulation of 2 µm intracavity power, stable mode-locking of the TDFL is successfully established by precisely matching the 2 µm cavity frequency with the intermode-beating frequency of the 1565 nm pump source. The mode-locked laser, without requiring any specific mode-locking element, can stably emit the rectangular nanosecond pulses. The mode-locking operation at the center wavelength of 1980.35 nm has a >61 dB signal-to-noise ratio and a 34.496 MHz repetition rate. Although the preliminary results are not better than those of conventional mode-locking, intermode beating mode-locking in combination with rare-earth-doped fiber lasers could provide a promising and alternative solution for compact, low-cost, and high-performance pulsed laser sources.

Bidirectional operation of 100 fs bound solitons in an ultra-compact mode-locked fiber laser.

We report on the experimental observation of bidirectional 100-fs bound solitons from a nanotube-mode-locked dispersion-managed Er-fiber laser with an ultra-simple linear cavity. Two mode-locked pulse trains in opposite directions are delivered simultaneously from the linear cavity. Under the pump power of <74 mW, both the bidirectional outputs of the laser work at the single-soliton state with pulse duration of 173 fs and 182 fs, respectively. Once the pump power is more than 74 mW, both the bidirectional outputs evolve into the two-soliton bound states with soliton separation of 1.53 ps. Interestingly, the bidirectional operations can show the different bound states, i.e. the forward bound solitons with phase difference of + π/2, and the backward ones with phase difference of -π/2. This is, to the best of our knowledge, the first demonstration of such compact bidirectional soliton fiber laser with the sub-200 fs pulses.

Compact self-Q-switched green upconversion Er:ZBLAN all-fiber laser operating at 543.4 nm.

We report the demonstration of a compact self-Q-switched green upconversion Er3+:ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber laser operating at 543.4 nm. The all-fiber green laser simply consists of a 45 cm high-concentration Er3+:ZBLAN fiber, a 976 nm pump source, and a pair of fiber end-facet mirrors. Under the strong excitation of the 976 nm pump laser, green upconversion lasing at 543.4 nm is achieved from the compact Er3+:ZBLAN fiber laser. Interestingly, the green laser exhibits stable self-Q-switching operation. As the 976 nm pump power is increased, the pulse repetition rate linearly increases from 25.9 to 50.8 kHz and the pulse width narrows from 7.2 to 1.95 µs. The Q-switched green laser has a pump threshold of 118 mW and a maximum output power of 6.9 mW with a slope efficiency of 30%. This is, to the best of our knowledge, the shortest-wavelength operation of a self-started or passively Q-switched fiber laser.

Hydroxytyrosol Protects against Myocardial Ischemia/Reperfusion Injury through a PI3K/Akt-Dependent Mechanism.

OBJECTIVE: To investigate the effects and mechanisms of hydroxytyrosol (HT) during the pathogenesis of myocardial ischemia reperfusion (I/R) in rat hearts. METHODS: The rats were randomized into five groups: sham group, I/R group, HT+I/R group, HT+LY294002+I/R group, and LY+I/R group. Myocardial infarct size, markers of oxidative stress, extent of myocardial apoptosis, echocardiographically assessed cardiac function, and expression of Akt and GSK 3ß were measured in each group. RESULTS: Prereperfusion administration of HT was associated with a significantly smaller area of myocardial infarction and remarkably decreased level of myocardial apoptosis and necrosis, as evidenced by a lower apoptotic index, reduced cleaved caspase-3, and the serum activities of lactate dehydrogenase and creatinine kinase MB. Moreover, HT also attenuated the impairment of cardiac systolic function. However, cotreatment with LY294002 and HT completely abolished the above cardioprotective effects of HT. A subsequent mechanistic study revealed that the cardioprotective effects of HT during the process of I/R of the myocardium were dependent on the activation of the Akt/GSK3ß pathway. CONCLUSION: Pretreatment with HT may have antiapoptotic and cardioprotective effects against myocardial I/R injury, and these effects seem to be related to the activation of the Akt/GSK3ß pathway in the myocardium.

The Periparturient Gut Microbiota's Modifications in Shaziling Sows concerning Bile Acids.

Shaziling pigs, as a native Chinese breed, have been classified as a fatty liver model. As the core of the whole pig farm, the sow's organism health is especially important, especially in the perinatal period; however, there are few reports on the perinatal intestinal microbiology and bile acid metabolism of Shaziling pig sows. The purpose of this research was to investigate the alterations in bile acids and gut microbiota of sows that occur throughout the perinatal period. Forty-two sows were selected for their uniformity of body conditions and were given the same diet. Fecal samples were collected for 16srDNA sequencing and bile acid targeted metabolome detection in four stages (3 days before delivery, 3 days after delivery, 7 days after delivery and 21 days after delivery). As revealed by the results, there were statistically significant variations in bile acids among the four stages, with the concentration of bile acids identified by SZL-4 being substantially greater than that of the other three groups (p < 0.05). When compared to the other three groups (p < 0.05), SZL-2 had considerably lower Shannon, Simpson and Chao 1 indices, and exhibited a statistically significant difference in ß-diversity. SZL-2 samples included a greater proportion of Proteobacteria than SZL-3 and SZL-4 samples; however, SZL-2 samples contained a smaller proportion of spirochetes than SZL-3 and SZL-4 samples. To a large extent, lactic acid bacteria predominated in the SZL-2 samples. The LEfSe analysis showed that the relative abundances of Lachnospiraceae_XPB1014_group, Christensenellaceae_R_7_group, Clostridium, Collinsella, Turicibacter, and Mollicutes_RF39_unclassified were the main differential bacteria in the SZL-1 swine fecal samples and the Eubacterium__coprostanoligenes_group in sow fecal samples from SZL-2. The relative abundance of Bacteroides, UBA1819, Enterococcus, Erysipelatoclostridium, and Butyricimonas in SZL-3 and SZL-4 Streptococcus, Coriobacteriaceae_unclassified, Prevotellaceae_UCG_001, Streptomyces, and Ochrobactrum in SZL-3. g_Collinsella was significantly and positively correlated with vast majority bile acids, and the g_Lachnospiraceae_XPB1014_group with GCDCA and GHDCA into positive correlations. Simultaneously, g_Streptococcus, g_Bacteroides, and g_UBA1819 inversely correlated with bile acid, accounting for the great bulk of the difference. In conclusion, there is an evident correlation between bile acids and gut microbiota in the perinatal period of Shaziling sows. Additionally, the discovery of distinct bacteria associated to lipid metabolism gives a reference for ameliorating perinatal body lipid metabolism disorder of sows through gut microbiota.

Hippocampal ß2­microglobulin mediates sepsis­induced cognitive impairment.

Acute brain dysfunction is a frequent complication in sepsis patients and is associated with long­term neurocognitive consequences and increased mortality, yet the underlying mechanism remains unclear. Emerging evidence has suggested that ß2­microglobulin [a component of major histocompatibility complex (MHC) class I molecules] is involved in cognitive dysfunction in various neurological diseases. Therefore, the present study tested the hypothesis that ß2­microglobulin in the brain also mediates sepsis­induced cognitive impairment. In the present study, wild­type and antigen processing 1 (Tap1)­deficient mice (Tap1­/­) were subjected to cecal ligation and puncture (CLP). Survival rate, cognitive function, and biochemical analysis were performed at the indicated time points. The data revealed that CLP induced anxiety­like behavior and impaired hippocampal­dependent contextual memory in wild­type mice, which was accompanied by hippocampal microglial activation, increased level of interleukin­1ß, and decreased concentrations of brain derived neurotrophic factor and postsynaptic density protein 95. Notably, it was demonstrated that Tap1­/­ mice with reduced cell surface expression of MHC I protected mice from anxiety­like behavior and impaired hippocampal­dependent contextual memory and reversed most of these biochemical parameters following sepsis development. In summary, the results of the present study suggest that ß2­microglobulin negatively regulates cognitive impairment in an animal model of sepsis induced by CLP.

Neuroinflammation-Induced Downregulation of Hippocampacal Neuregulin 1-ErbB4 Signaling in the Parvalbumin Interneurons Might Contribute to Cognitive Impairment in a Mouse Model of Sepsis-Associated Encephalopathy.

Sepsis-associated encephalopathy (SAE) is a common complication associated with poor prognosis in septic patients, but the underlying mechanism remains unclear. We hypothesized that disturbed neuregulin 1 (NRG1)-ErbB4 signaling in the parvalbumin interneurons was involved in sepsis-induced cognitive impairment in a mouse model of SAE. The SAE model was induced by cecal ligation/perforation (CLP). Animals were randomly divided into the following six groups: sham + vehicle group, sham + NRG1 group, CLP + vehicle group, CLP + NRG1 group, CLP + NRG1 + AG1478 (ErbB4 inhibitor) group, and CLP + minocycline group. Behavioral tests and in vivo electrophysiology were performed at the indicated time points. The brain tissues were harvested to determine the levels of hippocampcal cytokines, IBA1-positive cells, NRG1, ErbB4, and parvalbumin. In the present study, sepsis induced the anxiety-like behavior and hippocampal-dependent cognitive impairment, as reflected by significantly increased distance spent in the open field test and decreased freezing time to context in the fear conditioning test. The abnormal behavioral changes co-occurred with significant increases in hippocampal IBA1-positive cells, IL-1ß and IL-6 levels, and decreased NRG1, ErbB4, parvalbumin expressions, and evoked gamma activity. NRG1 treatment attenuated the sepsis-induced cognitive impairment and the associated biochemical markers, which were abolished by AG1478 administration. Notably, minocycline treatment attenuated neuroinflammation and mimicked the beneficial effects of NRG1 treatment. In summary, we provided additional evidence that the disruption of NRG1-ErbB4 signaling in the parvalbumin interneurons mediated by neuroinflammation might lead to abnormal gamma oscillations and thus contribute to cognitive impairment in a mouse model of SAE.

Disrupted Tryptophan Metabolism Induced Cognitive Impairment in a Mouse Model of Sepsis-associated Encephalopathy.

Sepsis-associated encephalopathy (SAE) is a common complication in critically ill patients and is associated with a poor prognosis. However, the precise mechanisms underlying sepsis-induced cognitive impairment remain largely to be elucidated. The aim of the present study was to investigate whether indoleamine 2, 3-dioxygenase (IDO) activation-mediated neurotoxicity is involved in the pathophysiology of sepsis-induced cognitive impairment. Sepsis was induced by cecal ligation/perforation (CLP). The animals were randomly divided into the following five groups: Sham + vehicle group; Sham + 1-methyl-D, L-tryptophan group; Sham + L-Kynurenine group; CLP + vehicle group; or CLP + 1-methyl-D, L-tryptophan group. The survival rate was estimated by the Kaplan-Meier method. Behavioral tests were performed by the open field and fear conditioning tests at days 13 and 14 after operation. In the present study, we demonstrated that sepsis induced a deficit in hippocampus-dependent cognitive impairment in a mouse model of SAE. Furthermore, a single peripheral kynurenine administration, the metabolic product of IDO, induced a deficit in the cognitive impairment in the sham mice. However, mice treated with IDO inhibitor 1-methyl-D, L-tryptophan were protected from sepsis-induced cognitive impairment. In conclusion, our study implicates IDO-dependent neurotoxic kynurenine metabolism as a critical factor responsible for the sepsis-induced cognitive impairment and a potential novel target for the treatment of SAE.