The quantification of transparent exopolymer particles (TEP) by colorimetric method is of large error and low repeatability, one major reason of which is related to the absence of clear definition ...and evaluation for part steps of the original method. It is obscure that the 80% sulfuric acid solution, acted as the extraction solution in the determination of TEP, is prepared based on a volume ratio or mass ratio. Furthermore, the change of solubility of recently available Gum Xanthan (GX) from the market means that the original protocol is no longer applicable, and the grinding of GX stock solution with a tissue grinder is replaced by shaking with a rotating shaker in the study to prevent the excessive dissolution of GX. We found that different preparation techniques could result in the varied concentrations of 80% H
2
SO
4
. The duration of shaking during the preparation of standard solution significantly affected the slope of the calibration curve, which caused different correction results of TEP. The impacts of different extraction solution concentrations and shaking time of GX solution on the quantification of TEP were investigated based on the field sampling and laboratory analysis. The extraction capacities of H
2
SO
4
with different concentrations for Alcian Blue were distinct, but had limited effect on the final measuring result of TEP. The change of the standard curve slope came along with the variation of shaking time, which markedly altered the detection limit and calibration result, and the extended shaking time was in favor of the determination of low-concentration TEP. It was suggested that the extraction solution concentration, shaking time and filtration volume of standard solution are required to be well controlled and selected to obtain more accurate results for TEP with different concentrations.
Residual antibacterial agents in 5909 animal and fishery products in Tokyo, Japan, were investigated over 17 consecutive years (2003-2019). Monitoring of 32 antibacterial agents (lincosamides, ...macrolides, penicillins, quinorones and tetracyclines) per product was accomplished via two steps: screening (by microbiological methods) and confirmation (by instrumental methods). Microbiological screening methods identified presumptive groups and determined semi-quantitative values. The instrumental methods quantified 81 residues of 11 different antibacterial agents in 72 samples. The screening strategy based on microbiological methods demonstrated the following: (i) the majority of the samples (over 99%) met Japanese regulations, (ii) using multiple methods provided a reliable inspection system with accurate quantitative values and (iii) there was a constant presence of tetracyclines and unexpected residues (lincomycin and norfloxacin) in various products. Thus, this long-term monitoring and screening strategy provided evidence that the frequencies and trends of residual antibacterial agents not only enhance food safety but also help to prevent antimicrobial resistance.
Brown algae from genus
form dense underwater forests that represent the most productive areas in the Mediterranean Sea. Due to the combined effects of global and local stressors such as climate ...change, urbanization, and herbivore outbreaks, there has been a severe decline in brown algal forests in the Mediterranean Sea. Natural recovery of depleted sites is unlikely due to the low dispersal capacity of these species, and efficient techniques to restore such habitats are needed. In this context, the aims of our study were (1) to improve and simplify the current ex situ laboratory protocol for the cultivation of
by testing the feasibility of some cost-effective and time-efficient techniques on two donor sites of
and (2) to evaluate the survival and growth of young thalli during the laboratory phase and during the most critical five months after out-planting. Specifically, the following ex situ cultivation methods were tested: (A) cultivation on clay tiles in mesocosms with culture water prepared by three different procedures (a) filtered seawater with a 0.22 μm filter membrane, (b) filtered seawater with a 0.7 μm filter membrane (GF), and (c) UV-sterilized water, and (B) cultivation on clay tiles in open laboratory systems. After two weeks, all thalli were fixed to plastic lantern net baskets suspended at a depth of 2 m in the coastal sea (hybrid method), and the algal success was monitored in relation to the different donor sites and cultivation protocol. The satisfactory results of this study indicate that UV-sterilized water is suitable for the cultivation of
in mesocosm, which significantly reduces the cost of the laboratory phase. This opens the possibility of numerous and frequent algal cultures during the reproductive period of the species. Additionally, if the young thalli remain in the lantern net baskets for an extended period of several months, they can grow significantly in the marine environment without being exposed to pressure from herbivorous fish.
Deep excavation engineering is a comprehensive discipline that involves multiple fields such as engineering geology, hydrogeology, and foundation engineering. With the improvement of the utilization ...rate of underground space, the demand for the construction of large-scale underground structural engineering is growing, making the excavation of underground soil become increasingly frequent, which also brings about the safety problems of deep foundation pit engineering and the surrounding environment. Prediction of foundation pit deformation is an important research direction with diverse historical developments, but it is also facing a series of difficulties and challenges. In order to solve these problems, this article proposes an improvement plan, establishes a prediction model based on the combination model of grey BP (back propagation) neural network, and verifies its effectiveness through experiments. The results show that the average error of the new model’s prediction of horizontal deformation is about 0.31, which is about 32% lower than the traditional model’s prediction error. The difference between the vertical deformation prediction and actual monitoring results is also controlled. The vertical deformation predicted by wavelet transform is 7% to 9% larger than the actual monitoring results, meeting the prediction requirements. Finally, this article explores the research on the prediction of foundation pit deformation in deep excavation engineering, An improved grey BP neural network combination model was proposed and its effectiveness was verified through experiments. This article has important reference value for the study of deformation prediction in deep excavation engineering.
Modeling methods have been proven to provide beneficial instrumental support for different modeling tasks during information system analysis and design. However, methods are a complex phenomenon that ...include constructs such as procedural guidelines, concepts to focus on, visual representations and cooperation principles. In general, method development is an expensive task that usually involves many stakeholders and results in various method iterations. Since methods and method development are complex in nature, there is a need for a well-structured and resource-efficient approach for method improvement. This paper aims to contribute to the field of method improvement by proposing a balanced scorecard-based approach and by reporting on experiences from developing and using it in the context of a method for information demand analysis. The main contributions of the paper are as follows: (1) It provides a description of the process for developing a scorecard for method improvement; (2) it shows how the scorecard as such can be used as a tool for improving a specific method; and (3) it discusses experiences from applying the scorecard in industrial settings.
Due to the problem of "true value agnostic" in the measurement of the real world, people believe that the existing methods can be closer to the true value by improving them. Therefore, they are ...willing to excessively affirm the more advanced method and deny the relatively "traditional" method. Taking the exchange rate method and purchasing power parity method commonly used in international economic comparison as examples, this paper generalizes the problems revealed by the exchange-rate-deviation index and concludes that there are at least three paradoxes in the deviation measurement of different methods. These paradoxes are the paradox of behavior significance, the paradox of comparative object, and the paradox of measurement result. The reason is that there is a cautionary trap in the improvement or innovation of measurement methods in reality. Sometimes the improved method is not necessarily better than the unimproved method. People tend to prefer advanced technology and methodology, but the problem of statistical input and related statistical benefits need to be considered in practical measurement. In fact, these basic problems still exist in some of the methods of economic statistics that we regard as common sense. When learning or introducing new methods, scholars do not absolutize the existing methods and conclusions. They should pay attention to critical experience, avoid the trap of improvement methods, and seek real improvement or innovation.
The paper presents an improved approach for investigating submarine groundwater discharge (SGD) based on radon mapping and radon mass balancing in the coastal sea. While the use of radon as an ...environmental tracer in SGD studies is well-established, we identified based on our longstanding experience six methodical shortcomings of the conventional approach and suggest corresponding developments. The shortcomings include: (1 and 2) inadequate consideration of both detection equipment response delay and influence of tidal stage; (3 and 4) incorrect quantification of radon losses, due to offshore mixing and degassing resulting in a potentially incorrect radon mass balance; (5) inaccurate determination of the terrestrial groundwater endmember, due to inhomogeneous radon distribution in the coastal aquifer; and (6) difficulties in distinguishing between discharged fresh groundwater and recirculated seawater. The improved approach is practically demonstrated in a step by step manner in a large-scale field study, which was carried out in False Bay (South Africa) and which consisted of two parts, namely (i) qualitative SGD localization along the entire False Bay coastline based on coastal radon distribution patterns and (ii) quantitative SGD investigation within a defined coastal area of interest (AOI) based on a radon mass balance (RMB). The plausibility of the AOI related results was evaluated by a hydrogeological model, used for qualitative SGD localization, and a hydrological model, applied for estimating groundwater recharge within the AOI catchment.
The present investigation deals with a method improvement to increase data throughput and reduce solvent consumption for both saturated and aromatic mineral oil hydrocarbon determination using a ...coupled liquid–gas chromatographic system. The starting point of this work was the method proposed by Biedermann, Fiselier, and Grob in 2009. A total time and solvent reduction of 34 and 23%, respectively, was obtained by speeding up the GC run and reducing the LC‐reconditioning step. The band broadening, occurring in the LC column during stop‐flow in the multitransfer mode, was assessed by comparing the variances of the perylene peak width recorded in the stop‐flow and normal modes. Band broadening directly proportional to the stop time of the LC pumps was observed, however, it did not affect the analytical reliability. A series of real samples (paperboards and pasta) was analyzed obtaining comparable results using both the reference and proposed method, both in the normal and multitransfer modes.
Aimed at wave load computation of floating hose, the paper analyzes the morphologic and mechanical characteristics
of offshore hose by establishing the partially immersed cylender model, and points ...out that the results of existing
Morison equation to calculate the wave loads of floating hose is not precise enough. Consequently, the improved Morison
equation has been put forward based on its principle. Classical series offshore pipeline has been taken as example which
applied in the water area of different depth. The wave loads of pipeline by using the improved Morison equation and
compared the calculation results with the existing Morison equation. Calculations for wave loads on pipelines in different
depth were accomplished and compared by the improved Morison equation and the existing Morison equation. Results
show that the improved Morison equation optimizes the accuracy of the computation of wave load on floating hose. Thus
it is more suitable for analyzing the effects of wave loads on floating hose and useful for mechanic analysis of offshore
pipeline.
High titers of lentiviral vectors are required for the efficient transduction of a gene of interest. During preparation of lentiviral the vectors, the protein of interest is inevitably expressed in ...the viral vector-producing cells. This expression may affect the production of the lentiviral vector.
We prepared lentiviral vectors expressing inwardly rectifying potassium channel (Lv-Kir2.1), its dominant-negative form (Lv-Kir-DN), and other K(+) channels, using the ubiquitously active β-actin and neuron-specific synapsin I promoters.
The titer of Lv-Kir-DN was higher than that of Lv-Kir2.1, suggesting a negative effect of induced K(+) currents on viral titer. We then blocked Kir2.1 currents with the selective blocker Ba(2+) during Lv-Kir2.1 production, and obtained about a 5-fold increase in the titer. Higher extracellular K(+) concentrations increased the titer of Lv-Kir2.1 about 9-fold. With a synapsin I promoter Ba(2+) increased the titer because of the moderate expression of Kir2.1 channel. Channel blockade also increased the titers of the lentivirus expressing Kv1.4 and TREK channels, but not HERG. The increase in titer correlated with the K(+) currents generated by the channels expressed.
In the production of lentivirus expressing K(+) channels, titers are increased by blocking K(+) currents in the virus-producing cells. This identifies a crucial issue in the production of viruses expressing membrane channels, and should facilitate basic and gene therapeutic research on channelopathies.
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