Poly(hydroxyethyl methacrylate) based magnetic nanoparticles for plasmid DNA purification from Escherichia coli lysate

The aim of this study is to prepare poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine) [PHEMAH] magnetic nanoparticles for plasmid DNA (pDNA) purification from Escherichia coli (E. coli) cell lysate. Magnetic nanoparticles were produced by surfactant free emulsion polymerization. mPHEMAH nanoparticles were characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), vibrating sample magnetometer (VSM), electron spin resonance (ESR), thermogravimetric analyses (TGA) and transmission electron microscopy (TEM). Surface area, average particle size and size distribution were also performed. Specific surface area of the mPHEMAH nanoparticles was found to be 1180 m²/g. Elemental analysis of MAH for nitrogen was estimated as 0.18 mmol/g polymer. The amount of pDNA adsorbed onto the mPHEMAH nanoparticles first increased and then reached a saturation value at around 1.0 mg/mL of pDNA concentration. Compared with the mPHEMA nanoparticles (50 μg/g polymer), the pDNA adsorption capacity of the mPHEMAH nanoparticles (154 mg/g polymer) was improved significantly due to the MAH incorporation into the polymeric matrix. The maximum pDNA adsorption was achieved at 25 °C. The overall recovery of pDNA was calculated as 92%. The mPHEMAH nanoparticles could be used six times without decreasing the pDNA adsorption capacity significantly. The results indicate that the PHEMAH nanoparticles promise high selectivity for pDNA.     

Art and Science behind Modified Starch Edible Films and Coatings: A Review

Technological advances have led to increased constraints regarding food packaging, mainly due to environmental issues, consumer health concerns, and economic restrictions associated therewith. Hence, food scientists and technologists are now more focused on developing biopolymer packages. Starch satisfies all the principal aspects making it a promising raw material for edible coatings/films. Modified starch has grabbed much attention, both at the academic as well as at the industrial level, because these films exhibit dramatic improvement in filming properties without involving any significant increase in cost of production. Various methods, additives used, and recent advances in the field of starch film production are discussed in detail in this review, which also provides an overview of the available information along with recent advances in modified starch film packaging.     

Quantifying machine flexibility

There are several studies aiming to quantify several aspects of flexibility in manufacturing systems like routing flexibility, product mix flexibility, volume flexibility, etc. However, there is still a need to develop more generic measures that can be used to quantify flexibility of systems in order to enable decision-makers to reach better decisions in selecting between different system configurations. In this study, a new approach which is based on digraph theory and matrix algebra is proposed to quantify flexibility. Several examples are also provided to illustrate the proposed approach and its practicality and usefulness. The proposed approach is a novel one and can be used to model and quantify several types of flexibilities. In this research, the proposed modelling approach is explained through machine flexibility mainly due to the fact that most of the other flexibility types in manufacturing systems rely on this flexibility type.     

Optimization of a Computer Simulation Model for Packing of Concrete Aggregates

A simulation algorithm was developed for modeling the dense packing of large assemblies of particulate materials (in the order of millions). These assemblies represent the real aggregate systems of portland cement concrete. Two variations of the algorithm are proposed: sequential packing model and particle suspension model. A developed multicell packing procedure as well as fine adjustment of the algorithm's parameters were useful to optimize the computational resources (i.e., to realize the trade-off between the memory and packing time). Some options to speed up the algorithm and to pack very large volumes of spherical entities (up to 10 million) are discussed. The described procedure resulted in a quick method for packing of large assemblies of particulate materials. The influence of model variables on the degree of packing and the corresponding distribution of particles was analyzed. Based on the simulation results, different particle size distributions of particulate materials are correlated to their packing degree. The developed algorithm generates and visualizes dense packings corresponding to concrete aggregates. These packings show a good agreement with the standard requirements and available research data. The results of the research can be applied to the optimal proportioning of concrete mixtures.     

Anthranilamide-pyrazolo[1,5-a]pyrimidine conjugates as p53 activators in cervical cancer cells

A library of new anthranilamide-pyrazolo[1,5-a]pyrimidine conjugates were designed, synthesized, and evaluated for their anticancer activity in cervical cancer cells such as HeLa and SiHa that possess low levels of p53. All 24 conjugates showed antiproliferative activity, while some of them exhibit significant cytotoxicity. In assays related to cell-cycle distribution, these conjugates induced G(2) /M arrest in HeLa cells and G(1) cell-cycle arrest in SiHa cells. Immunocytochemistry assays revealed that these compounds cause nuclear translocation of p53, thereby indicating the activation of p53. In cervical cancer cells, the p53 protein is degraded by E6 oncoprotein. Immunoblot and RT-PCR analyses proved the presence of mitochondria-mediated apoptosis with involvement p53 target genes such as BAX, Bcl2, and p21 (CDKI). Moreover, these compounds increased the phosphorylated forms of p53 and provide signals for apoptosis induction. Interestingly, one of the conjugates, (2-phenyl-7-(3,4,5-trimethoxyphenyl)pyrazolo[1,5-a]pyrimidin-5-yl)(4-(2-(thiophen-2-ylmethylamino)benzoyl)piperazin-1-yl)methanone, is the most promising candidate in this series and has the potential to be taken up for further detailed studies.     

ROOM OPEN POSTTION ON THE EFFECTS OF INDOOR NATURAL VENTILATION IN SUMMER

针对一般家庭中的典型客厅类型,运用计算流体力学方法对其夏季自然通风特性进行了数值模拟,分析了不同风道口高度对房间的速度场、温度场的影响,结果可为住宅设计提供相关的参考依据.     

Concanavalin A immobilized magnetic poly(glycidyl methacrylate) beads for antibody purification

Concanavalin A (Con A) immobilized magnetic poly(glycidyl methacrylate) (mPGMA) beads in monosize and spherical for (1.62 μm in diameter) were used for the purification of human immunoglobulin G (IgG) from human plasma. Con A was immobilized by covalent binding onto the mPGMA beads. The maximum IgG adsorption on the mPGMA-Con A beads was observed at pH 6.0. The nonspecific IgG adsorption onto the plain mPGMA beads was very low (0.22 mg/g). Scatchard analysis of the adsorption isotherm for IgG on mPGMA-Con A beads showed an affinity constant (K_a) of 1.39 × 10⁵ M⁻¹ and a theoretical maximum adsorption capacity of 109.1 mg/g. An apparent IgG adsorption capacity of 66.2 mg/g was observed under the experimental conditions. IgG adsorption capacity from human plasma was observed as 48.0 mg/g. The adsorption of human serum albumin from plasma was 2.0 mg/g. The total protein adsorption was determined to be 50.0 mg/g. IgG molecules could be repeatedly adsorbed and eluted with the mPGMA-Con A beads without noticeable loss in the IgG adsorption capacity. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Topography of brain sodium accumulation in progressive multiple sclerosis

Object

Sodium accumulation is involved in neuronal injury occurring in multiple sclerosis (MS). We aimed to assess sodium accumulation in progressive MS, known to suffer from severe neuronal injury.

Materials and methods

3D-²³Na-MRI was obtained on a 3T-MR-scanner in 20 progressive MS patients [11 primary-progressive (PPMS) and nine secondary-progressive (SPMS)] and 15 controls. Total sodium concentrations (TSC) within grey matter (GM), normal-appearing white matter (WM) and lesions were extracted. Statistical mapping analyses of TSC abnormalities were also performed.

Results

Progressive MS patients presented higher GM–TSC values (48.8 ± 3.1 mmol/l wet tissue vol, p < 0.001) and T₂lesions-TSC values (50.9 ± 2.2 mmol/l wet tissue vol, p = 0.01) compared to GM and WM of controls. Statistical mapping analysis showed TSC increases in PPMS patients confined to motor and somatosensory cortices, prefrontal cortices, pons and cerebellum. In SPMS, TSC increases were associated with areas involving: primary motor, premotor and somatosensory cortices; prefrontal, cingulate and visual cortices; the corpus callosum, thalami, brainstem and cerebellum. Anterior prefrontal and premotor cortices TSC were correlated with disability.

Conclusion

Sodium accumulation is present in progressive MS patients, more restricted to the motor system in PPMS and more widespread in SPMS. Local brain sodium accumulation appears as a promising marker to monitor patients with progressive MS.