Short-term dynamics of nutrients influenced by upwelling in a small oligotrophic coastal ecosystem, Gan Bay, in the northwest Philippines

We present a time-series analysis of nutrient and pCO(2) (partial pressure of CO2) levels in an oligotrophic coastal ecosystem (Gan Bay), which was likely to be influenced by upwelled subsurface water. Gan Bay is off Currimao Harbor, in the northwest Philippines and is located at the boundary of the South China Sea (SCS). This 42-h time-series observation was conducted in December 2006. In addition to continuous observations of dissolved oxygen (DO) and pCO(2), discrete samples were collected at a depth of 5 m every 3 h for measurements of nutrients, including soluble reactive phosphorus (SRP) and inorganic nitrogen (NO3- + NO2-) in order to examine their dynamics and possible physical and biological controls. We observed remarkably large short-term variations in the surface water, spanning a 10-fold change for SRP (32-330 nM) and from <0.3 mu M to 4.3 mu M for (NO3- + NO2-. DO also varied substantially from a lower end of 171 to 205 mu M O-2. Surface water pCO(2) changed from an equilibrium stage with the atmosphere (similar to 386 mu atm) to a stage where it was a significant source for the atmospheric CO2 (seawater pCO(2) similar to 469 mu atm). We found that the variation of nutrients was driven neither by tidal mixing nor by biological activities, as was suggested by the variations in the total bacterial abundance and chlorophyll a. Instead, our inverse T-S relationship suggested a two end-member mixing process during the observation period. The N:P ratio throughout the observation period was similar to 13.2, which is characteristic of SCS subsurface and deep waters. Moreover, pCO(2) was correlated inversely with the sea surface temperature. It is likely, therefore, that an upwelled subsurface cold water with high nutrients, low-temperature and high-pCO(2) existed. It should be noted that this upwelled cold water did not appear to impact the entire observation period (approximately 35 h of 42 h), which might suggest an extremely dynamic nature for this upwelled cold water mass. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved

Ischemic and haemorrhagic stroke risk estimation using a machine-learning-based retinal image analysis

BackgroundStroke is the second leading cause of death worldwide, causing a considerable disease burden. Ischemic stroke is more frequent, but haemorrhagic stroke is responsible for more deaths. The clinical management and treatment are different, and it is advantageous to classify their risk as early as possible for disease prevention. Furthermore, retinal characteristics have been associated with stroke and can be used for stroke risk estimation. This study investigated machine learning approaches to retinal images for risk estimation and classification of ischemic and haemorrhagic stroke.Study designA case-control study was conducted in the Shenzhen Traditional Chinese Medicine Hospital. According to the computerized tomography scan (CT) or magnetic resonance imaging (MRI) results, stroke patients were classified as either ischemic or hemorrhage stroke. In addition, a control group was formed using non-stroke patients from the hospital and healthy individuals from the community. Baseline demographic and medical information was collected from participants' hospital medical records. Retinal images of both eyes of each participant were taken within 2 weeks of admission. Classification models using a machine-learning approach were developed. A 10-fold cross-validation method was used to validate the results.Results711 patients were included, with 145 ischemic stroke patients, 86 haemorrhagic stroke patients, and 480 controls. Based on 10-fold cross-validation, the ischemic stroke risk estimation has a sensitivity and a specificity of 91.0% and 94.8%, respectively. The area under the ROC curve for ischemic stroke is 0.929 (95% CI 0.900 to 0.958). The haemorrhagic stroke risk estimation has a sensitivity and a specificity of 93.0% and 97.1%, respectively. The area under the ROC curve is 0.951 (95% CI 0.918 to 0.983).ConclusionA fast and fully automatic method can be used for stroke subtype risk assessment and classification based on fundus photographs alone

SINGLE MACHINE SCHEDULING WITH FORBIDDEN INTERVALS AND JOB DELIVERY TIMES

We consider a non-preemptive single machine scheduling problem with forbidden intervals. Associated with each job is a given processing time and a delivery time to its customer, when the processing of the job is complete. The objective is to minimize the time taken for all the jobs to be delivered to the customers. The problem is strongly NP-hard in general. In this study, we show that the case with a fixed number of forbidden intervals can be solved by a pseudo-polynomial time algorithm, while no polynomial time approximation algorithm with a fixed performance ratio exists for the case with two forbidden intervals. We also develop a polynomial time approximation scheme (PTAS) for the case with a single forbidden interval.Forbidden intervals, delivery times, polynomial time approximation algorithms, PTAS, performance ratio

A Novel Antibiotic Mechanism of l-Cyclopropylalanine Blocking the Biosynthetic Pathway of Essential Amino Acid l-Leucine

The unusual amino acid l-cyclopropylalanine was isolated from the mushroom Amanita virgineoides after detection in an anti-fungal screening test. l-Cyclopropylalanine was found to exhibit broad-spectrum inhibition against fungi and bacteria. The anti-fungal activity was found to be abolished in the presence of the amino acid l-leucine, but not any other amino acids, indicating that l-cyclopropylalanine may block the biosynthesis of the essential amino acid l-leucine, thereby inhibiting fungal and bacteria growth. Further biochemical studies found l-cyclopropylalanine indeed inhibits α-isopropylmalate synthase (α-IMPS), the enzyme that catalyzes the rate-limiting step in the biosynthetic pathway of l-leucine. Inhibition of essential l-leucine synthesis in fungal and bacteria organisms, a pathway absent in host organisms such as humans, may represent a novel antibiotic mechanism to counter the ever-increasing problem of drug resistance to existing antibiotics

Application of Optimized Fuzzy Comprehensive Evaluation Method in Water Quality Evaluation of Xiamen Bay

Based on the water quality monitoring data in the spring, summer and autumn of 2018 in Xiamen Bay, this study used the fuzzy comprehensive evaluation method to comprehensively evaluate the water quality. The results showed that the Western sea area of Xiamen, Tong'an Bay and Jiulong River estuary were seriously polluted areas, which were class Ⅳ water bodies; the water quality of southern sea area, eastern sea area and Dadeng sea area was in good condition, mainly class Ⅰ water body; DIN and DIP were the main pollutants affecting the water quality of Xiamen Bay; using the area ratio method on the basis of the results obtained by the fuzzy comprehensive evaluation method, the results showed that in 2018, Xiamen Bay as a whole was in Class Ⅲ water body condition, and the water quality needed to be further improved

Experimental research on compressive strength deterioration of coal seam floor sandstone under the action of acidic mine drainage

Abstract In sulphur-coal symbiotic coal seams, after the mining of sulphide iron ore, when the coal resources are mined, the mine water accumulated in the roadway mining area will have a certain impact on the stability of the surrounding rock of the coal seam roadway. Taking the floor sandstone of sulfur coal symbiotic coal seam as the research object, the roof fissure water with pH values of 7.48, 4.81 and 2.62 was used as the experimental solution. 10 experimental schemes were designed to measure the compressive strength of the samples under the action of AMD, and the hydrochemical analysis of AMD was conducted. The pore structures of the samples before and after the action of AMD were analyzed. Based on the hydrochemistry and pore structure, the deterioration mechanism of compressive strength of the coal seam floor sandstone under the action of AMD was explained. The results indicated that the compressive strength of the samples decreased with the increasing action time of AMD. The compressive strength decreased with the increment of the porosity. The concentration of H+ ion in AMD was relatively small. Na2O in albite dissolved and reacted with water, leading to an increase in the concentration of Na+ ion. Soluble substances such as MgCl2 and CaSO4 in the pore structure dissolved, leading to an increase in the concentration of Ca2+ and Mg2+ ions. The dissolution of soluble substances and the physical–chemical reactions between solutions and minerals were the essential causes of the continuous deterioration of the compressive strength of the coal seam floor sandstone. The results of this study can provide a theoretical basis for the deterioration of the mechanical properties of the peripheral rock in the roadway of the sulphur coal seam, and can also provide a certain engineering reference for the sulphur coal seam roadway

Corilagin attenuates the Parkinsonismin Japanese encephalitis virus induced Parkinsonism

This study evaluates the protective effect of corilagin against Parkinsonismin Japanese encephalitis virus (JEV) induced Parkinson’s disease. The JaGAr-01 strain of virus was used to induce JE. The virus was injected into the rats (13 days age) at the midpoint between the two ears. Adult rats, 12 week after the inoculation of virus, were used for the further study. Corilagin (20 mg/kg) and levodopa with dopa decarboxylase inhibitor (LEV, 10 mg/kg) were administered intraperitoneally for the duration of one week. Bradykinesia and the levels of dopamine in the brain were estimated at the end of protocol. There was a significant decrease inthe motor function in the corilagin, LEV and LEV + corilagin treated groupscompared to the negative control group. However treatment with corilagin, LEV and LEV + corilagin significantly increases the level of dopamine in the brain compared to the negative control group. This study concludes that corilagin ameliorates the Parkinsonismin JEV induced Parkinsonism. Moreover it shows a synergistic effect when treated with LEV. Data presented in the investigation supports that corilagin can be used clinically

Rationally designed Spot 42 RNAs with an inhibition/toxicity profile advantageous for engineering E. coli

Bacterial regulatory small RNAs (sRNAs) have shown promise for gene knock-down studies and metabolic engineering. However, some mRNAs might be difficult to target due to poor binding by the Hfq chaperone, individual synthetic sRNAs can have off-target effects, potential sRNA toxicities have not been studied globally, and a consensus on optimal sRNA design has yet to emerge. Here, Spot 42 sRNA is validated as an excellent scaffold by showing that its over-expression minimally affects the growth rate of Escherichia coli, and that inhibition is reliably achieved for all eight tested protein targets by designing antisense to target the first few codons. Two related sRNAs that could not be cloned, possibly due to lethality of the encoded sRNAs, became clonable when an eight-nucleotide sequence was inserted directly upstream of the antisense region. Global fitness costs for E. coli of the designer sRNAs were measured and found to be variable but tolerable. Importantly for utility, there was no correlation between target inhibition and cellular toxicity. As a proof of concept for applications, suppression of the UAG stop codon was improved by knock down of translation release factor 1 (RF1)