Design of a robust estimator for nonlinear kinetic modelling

A biased estimator for nonlinear kinetic modelling is studied. The proposed estimator contains two easily tuned parameters that enable the estimator to possess robustness in dealing with the problem of a nearly singular design matrix. The robustness of the estimator is discussed in detail, and the asymptotic normality of the estimator is proved concisely but rigorously. The regularity conditions imposed to obtain the results are fairly weak in engineering applications. Three examples presented demonstrate that the estimator is significantly better than the least-squares (LS) estimator and the ridge estimator in both estimate accuracy and convergence speed     

BAYQIK~——高浓度二氧化硫烟气制酸创新工艺

介绍拜耳技术服务公司开发的准等温接触高浓度二氧化硫烟气制酸创新工艺BAYQIK~。详述该工艺的理论基础、反应器结构、模型建立、中间试验以及在铅冶炼烟气制酸装置中的应用。BAYQIK~工艺的特点在于采用列管式固定床反应器,传统钒催化剂装在管内,冷却介质在壳程流动。氧化过程放出的热量被连续移走,从而使催化剂始终处于可承受的最高温度以下,即使反应器进气φ(SO_2)超过50%。BAYQIK~工艺可提供各种经济和工艺优点,包括可降低投资与操作成本,对于新建装置和扩能改造项目同样适用。     

FUNCTIONAL CHARACTERISTICS OF MUSTARD MUCILAGE

Mucilage found in hulls of yellow mustard seed was investigated. The isolated mucilage was a cold water-swellable hydrocolloid of low to medium viscosity and exhibited thixotropic properties. Viscosity increased with addition of alkali or acid. Mucilage produced synergistic increases in viscosity when combined with guar, locust bean, or carboxymethylcellulose. Solutions were opaque, bland tasting and slightly acidic. Solutions showed stability to acidity down to pH 3.5 and also to cooking and cooling cycles. The mucilage lowered the surface tension of water and the interfacial tensions of oil and water emulsions. Emulsification was achieved in model salad dressing formulations. The mucilage exhibited excellent suspending properties.     

Water Extractable Proteins of Porcine Muscle

SUMMARY: The study was performed on 31 samples of porcine muscle (m. longissimus dorsi) of different qualities, ranging from extremely pale, soft and exudative (PSE) to dark red in color, firm in structure and dry in appearance (DFD) in order to determine the water solubility of muscle proteins 24 hr post mortem. It was found that the water solubility of muscle proteins depends on the quality of the muscle, and is lowest in extremely PSE muscle. It was demonstrated, with the aid of electrophoresis on agar and acrylamide gels, that some sarcoplasmic proteins which undergo precipitation 30 min after adding a citrate-phosphate buffer (pH 4.6) at temperature of 20°C are extracted in smaller amounts from PSE muscle than from normal muscle. One of these fractions was benzidine positive.     

Impact of SARS-CoV-2 infection during pregnancy on postnatal brain development: The potential role of glial cells

Glial cells are crucial for maintaining central nervous system (CNS) homeostasis. They actively participate in immune responses, as well as form functional barriers, such as blood-brain barrier (BBB), which restrict the entry of pathogens and inflammatory mediators into the CNS. In general, viral infections during the gestational period can alter the embryonic and fetal environment, and the related inflammatory response may affect neurodevelopment and lead to behavioral dysfunction during later stage of life, as highlighted by our group for Zika virus infection. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) induces a cytokine storm and, during pregnancy, may be related to a more severe form of the coronavirus disease-19 (COVID-19) and also to higher preterm birth rates. SARS-CoV-2 can also affect the CNS by inducing neurochemical remodeling in neural cells, which can compromise neuronal plasticity and synaptic function. However, the impact of SARS-CoV-2 infection during pregnancy on postnatal CNS, including brain development during childhood and adulthood, remains undetermined. Our group has recently highlighted the impact of COVID-19 on the expression of molecular markers associated with neuropsychiatric disorders, which are strongly related to the inflammatory response. Thus, based on these relationships, we discussed the impact of SARS-CoV-2 infection either during pregnancy or in critical periods of neurodevelopment as a risk factor for neurological consequences in the offspring later in life, focusing on the potential role of glial cells. Thus, it is important to consider future and long-term public health concerns associated with SARS-CoV-2 infection during pregnancy.     

Diffusion of 51Cr in MgO Crystals

An arc fusion technique was used to grow single crystals of MgO with an aliovalent impurity level of ∼ 250 ppm. Diffusion coefficients for Cr³⁺ in single-crystal MgO were measured from 1353° to 1553°C using a high-specific-activity isotope,⁵¹ Cr. The diffusion coefficient of ⁵¹Cr for both arc-grown and vapor-deposited MgO crystals can be characterized by an activation energy of 70.0±2.1 kcal/mol. These results are comparable with the interdiffusion coefficients in Cr₂O₃-MgO when the interdif-fusion D is extrapolated to low Cr concentrations.     

Further Studies on the Formation of Nitrosamines in Cured Pork Products Packaged in Elastic Rubber Nettings

Traces of N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiethylamine (NDEA) can form in cured pork products packaged in elastic rubber nettings due to the interaction of nitrite in meat and amines in the rubber. Studies were carried out to determine whether taking nettings off immediately after processing or placing a layer of collagen as a barrier between nettings and meat could prevent or minimize formation of the above nitrosamines. None was effective. However, cured pork products packaged in a reformulated rubber netting, made with different amine additives, contained either none or only negligible levels of NDBA or NDEA, but, instead, contained 8–104 ppb levels of a new nitrosamine, N-nitrosodibenzylamine which is reported to be noncarcinogenic.