Effects of glucose,glutamine, and malate on the metabolism of spodoptera frugiperda clone 9 (sf9) cells

Optimal design and operation of bioreactors for insect cell culture is facilitated by functional relations providing quantitative information on cellular metabolite consumption kinetics, as well as on the specific cell growth rates (μ_G). Initial specific consumption rates of glucose, malate, and oxygen, and associated changes in μ_G, were measured forSpodoptera frugiperda clone 9 (Sf9) cells grown in batch suspension culture in medium containing 7–35 mM glucose, 0–16 mM malate, and 4–16 mM glutamine. The initial specific glucose consumption rate (q _G ) could be described by a modified Michaelis-Menten equation treating malate as a “competitive” inhibitorK ₁ = 6.5 mM) and glutamine as a “noncompetitive” inhibitorK _I = 14 mM) ofq _G , with aK _m of 7.1 mM for glucose. All three carbon sources were found to increase μ_G in a saturable manner, and a modified Monod equation was employed to describe this relationship (μ_Gmax = 0.047 h^-1). The initial specific oxygen consumption rate (q_O2) in Sf9 cells could be related to μ_G by the maintenance energy model, and it was calculated that, under typical culture conditions, about 15–20% of the cellular energy demand comes from functions not related to growth. Fitted parameters in mathematical expression for μg: K₄, Monod constant for glucose (mM); K₅, modified Monod constant for malate (mM); K₆, Monod constant for glutamine (mM); m_o2, specific consumption rate of oxygen by the cells under zero-growth conditions (nmol/cell/h); q_F, initial specific fumarate production rate (nmol/cell/ h);q _G , initial specific glucose consumption rate (nmol/cell/h); q_Gmax, maximum initial specific glucose consumption rate (nmol/cell/h);q _M , initial specific malate consumption rate (nmol/cell/h); q_o2, initial specific oxygen consumption rate (nmol/cell/h); Y_o2, cell yield on oxygen (cells/nmol); μ, initial specific cell growth rate (h^-1); μ_g, initial specific cell growth rate (h^-1); μG_max, maximum initial specific cell growth rate (h^-1).     

Production of oxy-rich air by RPSA for combustion use

The capital and energy costs of production of oxygen enriched air by a rapid pressure swing adsorption (RPSA) process can be reduced by decoupling the air drying and the air separation duties of the process. Integration of the oxygen-RPSA process with an enhanced combustion application system allows thermal swing adsorption drying of air feed to the RPSA process. The air separation process then can be run using an ad(de)sorption pressure envelope of 2:1 atmospheres, which significantly reduces the cost and energy of operation of the air compressor.     

三嗪噁二唑基吡唑衍生物抑酶活性的QSAR模型

基于拓扑化学理论,原子类型电拓扑态指数(Mk)被用于表征18种三嗪噁二唑基吡唑衍生物的化学微环境。采用最佳变量子集回归方法,分别建立上述化合物对蛋白酪氨酸磷酸酯酶1B(PTP1B)、细胞分裂周期25磷酸酯酶B(Cdc25B)的抑酶活性(P_t、C_d)与Mk的定量构效关系(QSAR)模型。它们的最佳三元QSAR模型的判定系数(R~2)依次为0.896、0.828,逐一剔除法交叉验证相关系数(R_(cv)~2)依次为0.830、0.688。经R_(cv)~2、VIF、FT、AC等检验,该模型具有良好的稳健性及预测能力。经训练集验证,上述模型均具有良好的外部预测能力。模型显示,影响Pt、Cd的因素既有不同的结构基团(-CH_3、-O-、-NH_2和芳环中-N=),也有相同的因素(芳环中-C=)。     

阴离子交换树脂回收水相中有机磷酸萃取剂

研究了阴离子交换树脂对水相中有机磷酸萃取剂的吸附。 通过比较不同的离子交换树脂对水相中2-乙基己基膦酸-单-2-乙基己基酯(P507)的去除率,发现大孔强碱性阴离子交换树脂(D201-OH)从水溶液中去除P507的能力最强,去除率可达99.24%。 而且当溶液在pH=1.0时,D201-OH对P507的吸附主要是分子吸附,其吸附等温线更适用于Langmuir模型;当溶液在pH=5.0时,阴离子交换反应占主导地位,其吸附等温线更适用于Freundlich模型。 研究还表明,D201-OH对P507的吸附在20 min内即达到吸附平衡时99.8%的吸附量。 通过动力学研究表明,拟一级动力学模型(R²>0.99)更适用于描述实验数据,并且吸附速率主要受膜扩散控制。 此外,吸附-解吸附循环8次后,D201-OH的吸附能力仍然保持在93%以上。 综上所述,D201-OH是有机磷酸类萃取剂的良好吸附剂,其吸附性能高效,循环过程稳定,因此可用于实际生产过程中回收有机磷酸萃取剂。     

Insights into the N-terminal Cu(II) and Cu(I) binding sites of the human copper transporter CTR1

Abstract

Copper transporter 1 (CTR1) is the main copper transporter in the eukaryotic system. CTR1 has several important roles: It binds Cu(II) ions that are present in the blood; it reduces those Cu(II) ions to Cu(I); and it subsequently transfers Cu(I) to the cytoplasmic domain, where the ion is delivered to various cellular pathways. Here, we seek to identify CTR1 binding sites for Cu(II) and Cu(I) and to shed light on the Cu(II)-to-Cu(I) reduction process. We focus on the first 14 amino acids of CTR1. This N-terminal segment is rich with histidine and methionine residues, which are known to bind Cu(II) and Cu(I), respectively; thus, this region has been suggested to have an important function in recruiting Cu(II) and reducing it to Cu(I). We utilize electron paramagnetic resonance (EPR) spectroscopy together with nuclear magnetic resonance (NMR) and UV-VIS spectroscopy and alanine substitution to reveal Cu(II) and Cu(I) binding sites in the focal 14-amino-acid segment. We show that H5 and H6 directly coordinate to Cu(II), whereas M7, M9, and M12 are involved in Cu(I) binding. This research is another step on the way to a complete understanding of the cellular copper regulation mechanism in humans.     

Simultaneous Stabilization of Potassium Metal and Superoxide in K–O2 Batteries on the Basis of Electrolyte Reactivity

In superoxide batteries based on O₂/O₂^? redox chemistry, identifying an electrolyte to stabilize both the alkali metal and its superoxide remains challenging owing to their reactivity towards the electrolyte components. Bis(fluorosulfonyl)imide (FSI^?) has been recognized as a “magic anion” for passivating alkali metals. The KFSI–dimethoxyethane electrolyte passivates the potassium metal anode by cleavage of S?F bonds and the formation of a KF‐rich solid–electrolyte interphase (SEI). However, the KFSI salt is chemically unstable owing to nucleophilic attack by superoxide and/or hydroxide species. On the other hand, potassium bis(trifluorosulfonyl)imide (KTFSI) is stable to KO₂, but results in mossy potassium deposits and irreversible plating and stripping. To circumvent this dilemma, we developed an artificial SEI for the metal anode and thus long‐cycle‐life K–O₂ batteries. This study will guide the development of stable electrolytes and artificial SEIs for metal–O₂ batteries.     

MnCl_2改性γ-Al_2O_3毛细管填充柱气相色谱分析氢同位素

针对常规气相色谱填充柱分析稳定氢同位素的柱效低、峰宽大、保留时间长等问题,采用MnCl_2改性γ-Al_2O_3填充的石英毛细管柱开展了系统性柱效分析及氢同位素分析技术研究。研究结果表明,使用MnCl_2对γ-Al_2O_3进行改性后,可大大改善单纯的γ-Al_2O_3表面有序度、孔结构和吸附性质,并将正氢(o-H_2)和仲氢(p-H_2)峰洗脱在单一谱峰区域内。制备的长1.0 m、内径0.53 mm的石英毛细填充柱与热导检测器(TCD)级联测试,在体积浓度1至10 m L/L范围内有较好的线性关系,对于低浓度样品检测的相对误差不大于5%。H_2、HD和D_2的保留时间可分别缩短至39、46和60 s,检出限可分别降低至0.046、0.067和0.072 m L/L。毛细管填充柱较常规填充柱具有峰形尖锐、相邻组分分离度高、保留时间短、检出限低等优点,可用于低浓度氢同位素快速测量及氢同位素在线分析。     

金属有机框架CPL-1填充柱气相色谱分析氢同位素

金属有机框架(MOFs)材料CPL-1的比表面积大、孔径均一,在低温条件下对氢同位素具有良好的量子筛分效应,是气相色谱固定相潜在的应用材料。采用CPL-1填充制备了长0.5 m、内径1 mm的微孔填充柱,借助单晶Al_2O_3颗粒间隙构建了色谱载气流通路径,在低温条件下探索研究了CPL-1填充柱的氢同位素分析性能。结果表明,在77 K时CPL-1对H_2和D_2的吸附量接近4 mmol/g,优于MnCl2/γ-Al_2O_3和γ-Al_2O_3,CPL-1填充柱在取样量0.25~2 mL范围内对低浓度氢同位素样品的检测具有良好的线性关系,检测的相对误差小于4%。CPL-1填充柱具有线性范围宽、重复性好、准确度高等优点,在氢同位素色谱分析中具有潜在的应用价值。     

基于网络媒体信息的传染病传播模型及其仿真研究

当一种突发传染病开始流行时,政府、媒体会以各种形式告知民众,有防范意识的民众将采取一定的防范措施来降低感染率.考虑面对一种突发传染病,将易感群体划分为具有防范意识和不具有防范意识两种群体,利用生命周期理论,分析网络媒体信息报道对传染病传播的影响,以此为依据建立一种改进的传染病传播模型(MSI).利用网络大数据得到对传染病有防范意识群体的观测值信息,利用神经网络技术对模型MSI的参数进行反演.然后对模型MSI数值仿真得到传染病传播过程,提出了相应的控制措施.     

The Hamilton–Waterloo Problem for ‐Factors and ‐Factors

The Hamilton–Waterloo problem asks for a 2‐factorization of (for v odd) or minus a 1‐factor (for v even) into ‐factors and ‐factors. We completely solve the Hamilton–Waterloo problem in the case of C₃‐factors and ‐factors for .