Model-based evaluation and process development of continuous chromatography

Multi-column periodic counter-current (PCC) chromatography has been proposed as continuous capturing technology to improve the process productivity and resin capacity utilization, as well as reduce buffer consumption and equipment footprint, which is applying for monoclonal antibody (mAb) capture with Protein A affinity resin. Due to the complexity of continues chromatography, some mathematical framework should be developed to aid the process development. Please click Additional Files below to see the full abstract

The Study of Dust Formation of Six Tidal Disruption Events

This paper investigates eleven (UV-)optical-infrared (IR) spectral energy distributions (SEDs) of six tidal disruption events (TDEs), which are ASASSN-14li, ASASSN-15lh, ASASSN-18ul, ASASSN-18zj, PS18kh, and ZTF18acaqdaa. We find that all the SEDs show evident IR excesses. We invoke the blackbody plus dust emission model to fit the SEDs, and find that the model can account for the SEDs. The derived masses of the dust surrounding ASASSN-14li, ASASSN-15lh, ASASSN-18ul, ASASSN-18zj, PS18kh, and ZTF18acaqdaa are respectively $\sim0.7-1.0\,(1.5-2.2)\times10^{-4}\,M_\odot$, $\sim0.6-3.1\,(1.4-6.3)\times10^{-2}\,M_\odot$, $\sim1.0\,(2.8)\times10^{-4}\,M_\odot$, $\sim0.1-1.6\,(0.3-3.3)\times10^{-3}\,M_\odot$, $\sim1.0\,(2.0)\times10^{-3}\,M_\odot$, and $\sim 1.1\,(2.9)\times10^{-3}\,M_\odot$, if the dust is graphite (silicate). The temperature of the graphite (silicate) dust of the six TDEs are respectively $\sim1140-1430\,(1210-1520)$\,K, $\sim1030-1380\,(1100-1460)$\,K, $\sim1530\,(1540)$\,K, $\sim960-1380\,(1020-1420)$\,K, $\sim900\,(950)$\,K, and $\sim1600\,(1610)$\,K. By comparing the derived temperatures to the vaporization temperature of graphite ($\sim 1900$\,K) and silicate ($\sim 1100-1500$\,K), we suggest that the IR excesses of PS18kh can be explained by both the graphite and silicate dust, the rest five TDEs favor the graphite dust while the silicate dust model cannot be excluded. Moreover, we demonstrate the lower limits of the radii of the dust shells surrounding the six TDEs are significantly larger than those of the radii of the photospheres at the first epochs of SEDs, indicating that the dust might exist before the the TDEs occurred.Comment: 13 pages, 4 figures, 4 tables, submitted to Ap

Poly[[(μ-1H-benzimidazole-5,6-dicarboxyl­ato)zinc(II)] monohydrate]

The three-dimensional polymeric title compound, {[Zn(C9H4N2O4)]·H2O}n, contains one crystallographically independent ZnII atom, one fully deprotonated 1H-benzimid­azole-5,6-dicarboxyl­ate (bdc) ligand and one uncoordinated water mol­ecule. The ZnII atom is four-coordinated by three O atoms and one N atom from the bdc ligands, giving a distorted tetra­hedral coordination geometry. The uncoordinated water mol­ecule is bound to the main structure through a strong bdc–water N—H⋯O hydrogen bond, and two much weaker water–bdc O—H⋯O inter­actions

A Novel Equivalent Continuous Metering Control With a Uniform Switching Strategy for Digital Valve System

Pulse number modulation (PNM) combined with pulse width modulation (PWM) control is an effective solution to improve the resolution of digital valve systems. However, the numerous discrete variables that use parallel on / off valves cause difficult control coordination and uneven switching. To address this issue, this article defines the equivalent spool displacement of the digital flow control unit by the number of PNM-controlled valves and the duty cycle of PWM-controlled valves to replace multiple discrete variables and develops the equivalent continuous metering control method. Furthermore, a uniform switching control strategy is proposed for the PWM-controlled valve using a uniformly distributed permutation for each on / off valve. The proposed control methods are verified by simulation on the built mathematical model of the equal-coded digital valve system. Experimental results for the displacement control of a hydraulic cylinder at 1 rad/s show that the average error of the equivalent continuous metering control is about 0.236 mm and the dispersion index reaches 20%, while the uniform switching control strategy achieves 80% with an average error of 0.215 mm. Simulated and experimental results demonstrate that the equivalent continuous metering control with a uniform switching strategy can almost evenly distribute switching numbers without compromising the accuracy of the displacement control.Peer reviewe

Polarization-based probabilistic discriminative model for quantitative characterization of cancer cells

We propose a polarization-based probabilistic discriminative model for deriving a set of new sigmoid-transformed polarimetry feature parameters, which not only enables accurate and quantitative characterization of cancer cells at pixel level, but also accomplish the task with a simple and stable model. By taking advantages of polarization imaging techniques, these parameters enable a low-magnification and wide-field imaging system to separate the types of cells into more specific categories that previously were distinctive under high magnification. Instead of blindly choosing the model, the L0 regularization method is used to obtain the simplified and stable polarimetry feature parameter. We demonstrate the model viability by using the pathological tissues of breast cancer and liver cancer, in each of which there are two derived parameters that can characterize the cells and cancer cells respectively with satisfactory accuracy and sensitivity. The stability of the final model opens the possibility for physical interpretation and analysis. This technique may bypass the typically labor-intensive and subjective tumor evaluating system, and could be used as a blueprint for an objective and automated procedure for cancer cell screening

Cooperative co-evolutionary module identification with application to cancer disease module discovery

none10siModule identification or community detection in complex networks has become increasingly important in many scientific fields because it provides insight into the relationship and interaction between network function and topology. In recent years, module identification algorithms based on stochastic optimization algorithms such as evolutionary algorithms have been demonstrated to be superior to other algorithms on small- to medium-scale networks. However, the scalability and resolution limit (RL) problems of these module identification algorithms have not been fully addressed, which impeded their application to real-world networks. This paper proposes a novel module identification algorithm called cooperative co-evolutionary module identification to address these two problems. The proposed algorithm employs a cooperative co-evolutionary framework to handle large-scale networks. We also incorporate a recursive partitioning scheme into the algorithm to effectively address the RL problem. The performance of our algorithm is evaluated on 12 benchmark complex networks. As a medical application, we apply our algorithm to identify disease modules that differentiate low- and high-grade glioma tumors to gain insights into the molecular mechanisms that underpin the progression of glioma. Experimental results show that the proposed algorithm has a very competitive performance compared with other state-of-the-art module identification algorithms.noneHe, S and Jia, G and Zhu, Z and Tennant, DA and Huang, Q and Tang, K and Liu, J and Musolesi, M and Heath, JK and Yao, XHe, S and Jia, G and Zhu, Z and Tennant, DA and Huang, Q and Tang, K and Liu, J and Musolesi, M and Heath, JK and Yao,

Genome-wide patterns of genetic variation in sweet and grain sorghum (Sorghum bicolor)

10.1186/gb-2011-12-11-r114Genome Biology1211-GNBL

Heavy metal and nutrient concentrations in top- and sub-soils of greenhouses and arable fields in East China – Effects of cultivation years, management, and shelter

Although greenhouse vegetable production in China is rapidly changing, consumers are concerned about food quality and safety. Studies have shown that greenhouse soils are highly eutrophicated and potentially contaminated by heavy metals. However, to date, no regional study has assessed whether greenhouse soils differ significantly in their heavy metal and nutrient loads compared to adjacent arable land. Our study was conducted in Shouguang County, a key region of greenhouse vegetable production in China. Soil samples down to soil depths of 3 m were taken from 60 greenhouse vegetable fields of three different ages (5, 10, and 20 years) and from 20 adjacent arable fields to analyze the concentrations of heavy metals, nutrients, and soil physio-chemical parameters. A comparison of greenhouse soils with adjacent arable fields revealed that for greenhouses, (a) micro (heavy metals: Cu, Zn, and Mn) and macronutrients (Nmin, Olsen-P, available K) were significantly higher by a factor of about five, (b) N:P:K ratios were significantly imbalanced towards P and K, and (c) topsoil (0–30 cm) concentrations of the above-mentioned micro- and macronutrients increased with years of vegetable cultivation. In contrast, the soil concentrations of the heavy metals Cr and Pb were lower in greenhouse soils. Heavy metal concentrations did not vary significantly with soil depth, except for the micronutrients Cu and Zn, which were between 1- and 3-fold higher in the topsoil (0–30 cm) than in the subsoil (30–300 cm). The Nemerow pollution index (PN) was 0.37, which was below the recommended environmental threshold value (PN < 1). Structural equation model analysis revealed that soil nutrient concentrations in greenhouse soils are directly related to the input of fertilizers and agrochemicals. Lower values of soil Pb and Cr concentrations in greenhouses were due to the sheltering effect of the greenhouse roof, which protected soils from atmospheric deposition due to emissions from nearby industrial complexes