A tuned ocean color algorithm for the Arctic Ocean: a solution for waters with high CDM content.

The Arctic Ocean (AO) is the most river-influenced ocean. Located at the land-sea interface wherein phytoplankton blooms are common, Arctic coastal waterbodies are among the most affected regions by climate change. Given phytoplankton are critical for energy transfer supporting marine food webs, accurate estimation of chlorophyll a concentration (Chl), which is frequently used as a proxy of phytoplankton biomass, is critical for improving our knowledge of the Arctic marine ecosystem and its response to the ongoing climate change. Due to the unique and complex bio-optical properties of the AO, efforts are still needed to obtain more accurate Chl estimates, especially for coastal waters with high colored detrital material (CDM) content. In this study, we optimized the the Garver-Siegel-Maritorena (GSM) algorithm, using an Arctic bio-optical dataset comprised of seven wavelengths (the original GSM wavelengths plus 625 nm). Results suggested that our tuned algorithm, denoted GSMA, outperformed an alternative AO GSM algorithm denoted AO.GSM, but the accuracy of Chl estimates was only improved by 8%. In addition, GSMA showed appreciable robustness when assessed using a satellite image and two non-Arctic coastal datasets.

Research on the matching characteristics of the theoretical digging force of a backhoe hydraulic excavator.

The theoretical digging force is the maximum digging resistance that an excavator can overcome, which is an important measure of its digging capacity. To study the matching of the digging capacity with the actual demand and the matching of the working device mechanism, a 36.5 t backhoe hydraulic excavator is used as an example to analyse the distributions of the digging resistance under two different normal digging area working conditions and the maximum digging resistance characteristics of the tool. An appropriate digging postures are selected, based on limit digging force and compound digging force models, the theoretical digging forces under the two working conditions are obtained and matched with the measured digging resistance force values and the limiting factors affecting the digging force. The results show that the average percentage of theoretical digging forces greater than the measured digging resistance under both calculation models is 84.06% rather than 100%. The results of different digging methods all indicate that small chamber locking of the boom cylinder is too often the limiting factor for the digging force, resulting in poor matching of the working device. This study provides guidance for the improvement of the theoretical digging force model and the evaluation of the matching characteristics of the working device.

A Strategy Study on Risk Communication of Pandemic Influenza: A Mental Model Study of College Students in Beijing.

PURPOSE: To understand the characteristics of risk perception of influenza pandemic in college students with prominent frequency and the differences between these risk perceptions and professionals. Then, offering a proposal for the government to improve the efficiency of risk communication and health education. METHODS: According to the mental model theory, researchers first draw a framework of key risk factors, and then they ask these students about the understanding of the framework with questionnaire and then making concept statistics and content analysis on the respondents' answers. RESULTS: Researchers find some students' misunderstanding of pandemic including excessive optimism to the consequences of a pandemic, a lack of detailed understanding of mitigation measures, and negative attitudes towards health education and vaccination. Most students showed incomplete and incorrect views about concepts related to the development and exposure factors, impact and mitigation measures. Once threatened, it may lead to the failure of decision-making. The majority of students we interviewed had positive attitudes towards personal emergency preparedness for a pandemic influenza and specialized health education in the future. CONCLUSION: Researchers suggest that the government should make a specific pandemic guidance plan by referring to the risk cognitive characteristics of college students shown in the research results, and update the methods of health education to college students.

Intercity variability and local factors influencing the level of pesticide residues in marketed fruits and vegetables of China.

Controlling pesticide residues in marketed fruits and vegetables is an essential issue for food safety and public health. Local governments improve local conditions, like policymaking and implementation, economic structure and development level, and agricultural practices, to control pesticide residues. However, the level of influence and relative importance of these local factors are not analyzed quantitatively. Here we present the food safety level across 42 Chinese cities as measured by the level of pesticide residues (LPR) in fresh fruits and vegetables, and explore how local socio-economic and policy factors influence its intercity variability. A total of 12,070 sample measurements were used in this study. The relationships between LPR and local socio-economic-policy factors were tested by using Pearson correlation analysis, two-sided independent t-test, and stepwise multivariable linear regression. Our analysis shows that: (1) the pesticide residues in 97.1% of the samples were within legal limits, but the LPR had a considerable cross-city disparity and (2) eight socio-economic-policy variables were found to be significantly correlated with LPR at the city level. Six policy-related variables, namely the number of pesticide-related policies, the number of food safety-related policies, the number of food safety-related news reports, the supermarket revolution, the administrative level of the city and the transparency of supervision of food safety, could explain 32.8% of the intercity variability of LPR. This was followed by the gross domestic product (GDP) per capita from the tertiary sector (15.6%) and the pesticide usage per cultivated area in local agriculture (13.4%). After eliminating the collinearity of these variables, local socio-economic-policy factors collectively could explain around 40% of the intercity variability of LPR. This indicates that local-level policy may have a larger impact on local food safety in terms of LPR than economic factors or local agricultural practice, underscoring the critical role of local government in ensuring food safety.

Efficacy of Shegan Mahuang Decoction for asthma: A systematic review and meta-analysis protocol.

BACKGROUND: Shegan Mahuang Decoction (SMD) was used widely for treatment of asthma in China; however, the clinical effect of SMD on asthma was not well concluded. METHODS: Seven electronic databases (Medline, Cochrane library, EMBASE database, Chinese National Knowledge Infrastructure, Wanfang database, Chongqing VIP database, and Chinese Biomedicine database) will be searched for randomized controlled trials which meet the eligible criteria. Two reviewers will select studies and extract data independently. Risk of bias will be evaluated using modified Jadad score. Data synthesis will be carried out using RevMan 5.3. Sensitivity analysis and publication bias will also be investigated. RESULTS: This systematic review and meta-analysis will review and synthesis current clinical evidence of SMD for the treatment of asthma. CONCLUSION: This systematic review and meta-analysis will provide high quality evidence of SMD for the treatment of asthma. REGISTRATION: PROSPERO CRD42019141810.

Clinical outcomes of prolonged infusion (extended infusion or continuous infusion) versus intermittent bolus of meropenem in severe infection: A meta-analysis.

BACKGROUND: Meropenem exhibits time-dependent antimicrobial activity and prolonged infusion (PI) (extended infusion or continuous infusion, EI or CI) of meropenem can better achieve pharmacodynamics target when comparing with intermittent bolus (IB). However, the clinical outcomes between two groups remain inconclusive. OBJECTIVE: To evaluate current published literatures by meta-analysis to ascertain whether PI of meropenem can improve clinical outcomes. METHODS: Medline, Cochrane database and EMBASE were searched. Randomized control trails (RCT) and observational studies which compared the clinical outcomes of PI and IB groups were included and evaluated for quality. The data of studies were extracted and meta-analysis was performed using Revman 5.3 software. RESULTS: Six RCTs and 4 observation studies with relatively high quality were included in this analysis. Compared to IB group, PI group had a higher clinical success rate (odd ratio 2.10, 95% confidence interval 1.31-3.38) and a lower mortality (risk ratio 0.66, 95% confidence interval 0.50-0.88). The sensitivity analysis showed the results were stable. CONCLUSION: PI of meropenem was associated with a higher clinical improvement rate and a lower mortality. It is recommended for patients with severe infection or infected by less sensitive microbial.

Statistical Analysis of SSMIS Sea Ice Concentration Threshold at the Arctic Sea Ice Edge during Summer Based on MODIS and Ship-Based Observational Data.

The threshold of sea ice concentration (SIC) is the basis for accurately calculating sea ice extent based on passive microwave (PM) remote sensing data. However, the PM SIC threshold at the sea ice edge used in previous studies and released sea ice products has not always been consistent. To explore the representable value of the PM SIC threshold corresponding on average to the position of the Arctic sea ice edge during summer in recent years, we extracted sea ice edge boundaries from the Moderate-resolution Imaging Spectroradiometer (MODIS) sea ice product (MOD29 with a spatial resolution of 1 km), MODIS images (250 m), and sea ice ship-based observation points (1 km) during the fifth (CHINARE-2012) and sixth (CHINARE-2014) Chinese National Arctic Research Expeditions, and made an overlay and comparison analysis with PM SIC derived from Special Sensor Microwave Imager Sounder (SSMIS, with a spatial resolution of 25 km) in the summer of 2012 and 2014. Results showed that the average SSMIS SIC threshold at the Arctic sea ice edge based on ice-water boundary lines extracted from MOD29 was 33%, which was higher than that of the commonly used 15% discriminant threshold. The average SIC threshold at sea ice edge based on ice-water boundary lines extracted by visual interpretation from four scenes of the MODIS image was 35% when compared to the average value of 36% from the MOD29 extracted ice edge pixels for the same days. The average SIC of 31% at the sea ice edge points extracted from ship-based observations also confirmed that choosing around 30% as the SIC threshold during summer is recommended for sea ice extent calculations based on SSMIS PM data. These results can provide a reference for further studying the variation of sea ice under the rapidly changing Arctic.

15-HETE mediates sub-acute hypoxia-induced TRPC1 expression and enhanced capacitative calcium entry in rat distal pulmonary arterial myocytes.

Sub-acute hypoxia causes pulmonary vasoconstriction (HPV) is associated with increased intracellular Ca(2+) concentration ([Ca(2+)](i)) and contraction of pulmonary arterial smooth muscle cells (PASMCs). We previous have demonstrated that 15-hydroxyeicosatetraenoic acid (15-HETE), a metabolite of arachidonic acid by 15-lipoxygenase (15-LO), causes elevated [Ca(2+)](i) in PASMCs partly through Ca(2+) entry via other than L-type Ca(2+) channels. In this study, we used SKF96365/La(3+) (SOCC antagonists) and Nordihydro-guiairetic acid (NDGA, a blockage of 15-LO) to examine the effect of 15-HETE on capacitative Ca(2+) entry and activity/expression of store-operated Ca(2+) channels (SOCCs) during sub-acute hypoxic procedure and the contribution of SOCCs on the maintenance of vascular tones. The results showed that the 15-HETE induced constriction of PA rings from normoxic and sub-acute hypoxic rats can be abolished by SKF96365 and La(3+). Capacitative Ca(2+) entry (CCE) was also enhanced in PASMCs cultured with 15-HETE under sub-acute hypoxic condition (3% O(2), 48h) and incubation with NDGA in PASMCs can greatly suppress this enhancement. Moreover, TRPC1, not TRPC4 and TRPC6, mRNA and protein expression were increased in PASMCs during these procedures. Meanwhile, the effect of 15-HETE on CCE and TRPC1 expression under sub-acute hypoxic cultivation were greatly suppressed in 15-LO knockdown PASMCs and PAs. These results suggest that 15-HETE mediated HPV through increased TRPC1 expression, leading to enhanced CCE, contributing to the maintenance of vascular tone.

Functional impact of the hyperpolarization-activated current on the excitability of myelinated A-type vagal afferent neurons in the rat.

1. The hyperpolarization-induced, cation-selective current I(h) is widely observed in peripheral sensory neurons of the vagal and dorsal root ganglia, but the peak magnitude and voltage- and time-dependent properties of this current vary widely across afferent fibre type. 2. Using patch clamp investigations of rat isolated vagal ganglion neurons (VGN) identified as myelinated A-type afferents, we established a compendium of functional correlates between changes in membrane potential and the dynamic discharge properties of these sensory neurons as a result of the controlled recruitment of I(h) using the current clamp technique. 3. Two robust responses were observed in response to hyperpolarizing step currents: (i) upon initiation of the negative step current, there was a rapid hyperpolarization of membrane potential followed by a depolarizing voltage sag (DVS) towards a plateau in membrane potential as a result of steady state recruitment of I(h); and (ii) upon termination of the negative step current, there was a rapid return to the pretest resting membrane potential that often led to spontaneous action potential discharge. These data were strongly correlated (r(2) > 0.9) with a broad compendium of dynamic discharge characteristics in these A-type VGN. 4. In response to depolarizing step currents of increasing magnitude, the discharge frequency of the A-type VGN responded with increases in the rate of sustained repetitive discharge. Upon termination of the depolarizing step current, there was a post-excitatory membrane hyperpolarization of a magnitude that was strongly correlated with action potential discharge rate (r(2) > 0.9). 5. Application of the selective hyperpolarization-activated cyclic nucleotide gated (HCN) channel blockers ZD7288 (10 micromol/L) or CsCl (1.0 mmol/L) abolished I(h) and all of the aforementioned functional correlates. In addition to reducing the excitability of the A-type VGN to step depolarizing currents. 6. Because there is increasing evidence that the HCN channel current may represent a valid target for pharmacological intervention, the quantitative relationships described in the present study could potentially help guide the molecular and/or chemical modification of HCN channel gating properties to effect a particular outcome in VGN discharge properties, ideally well beyond merely selective blockade of a particular HCN channel subtype.

Hepatic angiomyolipoma: a clinical experience in diagnosis and treatment.

BACKGROUND: Hepatic angiomyolipoma is a rare mesenchyme-derived neoplasm often misdiagnosed as hepatocellular carcinoma, and the treatment for it remains controversial. AIMS: To develop the optimal preoperative diagnoses means and treatment modalities of hepatic angiomyolipoma. METHODS: Retrospective analysis of the clinical features, treatment, and prognostic data of 17 hepatic AML patients admitted to Chinese People's Liberation Army Generation Hospital between 1996 and 2006. RESULTS: Most hepatic angiomyolipoma were solitary. The overall preoperative diagnostic rate was 18% and the most common misdiagnosis was hepatocellular carcinoma (10/17, 59%). In three patients, observation was performed for 2-3 years before being admitted. The tumors increased 1-9 cm in size in all patients. All of the 17 patients finally received various liver resection procedures, and postoperative mortality and morbidity was 0 and 12% (2/17). After a median follow-up period of 73 months, the tumor recurred only in one patient 9 years post-operatively. CONCLUSIONS: Hepatic angiomyolipoma should be suspected in liver tumor patients with normal α-fetoprotein levels and no concomitant hepatitis. Preoperative MRI combined with percutaneous fine-needle biopsy should be the diagnostic methods of choice. Small hepatic AML proved through pathologic examination (<5 cm) may be managed by observation with close follow-up, but surgery is indicated in patients suffering from large tumors or significantly larger tumors during follow-up.