高固体分丙烯酸树脂合成工艺条件探讨

高固体分丙烯酸树脂是目前环保树脂研究的一个很重要的分支,本文选择合适的丙烯酸单体,用溶液聚合法合成了一种高固体分丙烯酸树脂,并详细讨论了反应温度、加料时间及保温时间等工艺条件对合成树脂性能的影响。     

Polystyrene Containing Carbinolamine/Azomethine Potentially Useful as Antimicrobial Agent: Synthesis and Biological Evaluation

An investigation of antimicrobial properties of 12 novel modified polymer derived from the condensation reaction of (aminomethyl)polystyrene and four substitute salicylaldehyde (2-hydroxy benzaldehyde, 5-fluoro-2 hydroxy benzaldehyde, 5-fluoro-3-chloro-salicylaldehyde and 5-fluoro-3-methyl-salicylaldehyde) has been carried out and Cr(III) and Ni(II) complexes have been prepared. Modified polymers were characterized by magnetic susceptibility, elemental analyses, and spectral studies. The ¹H NMR and ¹³C NMR spectra analysis of the polymeric carbinolamine/azomethine were determined. In addition, surface morphology and composition were determined by SEM/EDX. Thermo gravimetric analyses of polymers were carried out in nitrogen atmosphere. Antibacterial activities of the polymers attached carbinolamine/azomethine and their complexes were studied by the well-diffusion method against Listeria monocytogenes 4b, Staphylococcus aureus, Escherichia coli, Salmonella typhi H, Brucella abortus, Staphylococcus epidermis sp., Micrococcus luteus, Shigella dysenteria type 10, Bacillus cereus, Pseudomonas putida and antifungal activity against Candida albicans.     

Trend Assessment by the Innovative-Şen Method

Hydro-meteorological time series may include trend components mostly due to climate change since about three to four decades. Trend detection and identification in a better and refined manner are among the major current research topics in water resources domain. Even though different methodologies can be found for trend detection in literature, two well-known procedures are the Mann-Kendall (MK) trend test and recently innovative-?en trend method, which provides different aspects of the trend. The theoretical basis and application of these two methods are completely different. The MK test gives a holistic monotonic trend without any categorization of the time series into a set of clusters, but the innovative-?en method is based on cluster and provides categorical trend behavior in a given time series. The main purpose of this paper is to provide important differences between these two approaches and their possible similarities. The applications of the two approaches are given for hydro-meteorological records including relative humidity, temperature, precipitation and runoff from Ergene drainage basin in the north-western part of Turkey. It is observed that although MK trend test does not show significant trend almost in all the cases, the innovative-?en approach yields trend categorizations as “very low”, “low”, “medium” “high” and “very high”, which should be taken into consideration in future flood (“very high”) and drought (“very low”) studies.     

Formulation studies for mirtazapine orally disintegrating tablets

Abstract

Objective: Orally disintegrating tablets (ODTs) recently have gained much attention to fulfill the needs for pediatric, geriatric, and psychiatric patients with dysphagia. Aim of this study was to develop new ODT formulations containing mirtazapine, an antidepressant drug molecule having bitter taste, by using simple and inexpensive preparation methods such as coacervation, direct compression and to compare their characteristics with those of reference product (Remereon SolTab).

Materials and methods: Coacervation method was chosen for taste masking of mirtazapine. In vitro characterization studies such as diameter and thickness, weight variation, tablet hardness, tablet friability and disintegration time were performed on tablet formulations. Wetting time and in vitro dissolution tests of developed ODTs also studied using 900?mL 0.1?N HCl medium, 900?mL pH 6.8 phosphate buffer or 900?mL pH 4.5 acetate buffer at 37?±?0.2?°C as dissolution medium.

Results: Ratio of Eudragit® E-100 was chosen as 6% (w/w) since the dissolution profile of A1 (6% Eudragit® E-100) was found closer to the reference product than A2 (4% Eudragit® E-100) and A3 (8% Eudragit® E-100). Group D, E and F formulations were presented better results in terms of disintegration time. Dissolution results indicated that Group E and F formulations showed optimum properties in all three dissolution media.

Discussion: Formulations D1, D4, D5, E3, E4, F1 and F5 found suitable as ODT formulations due to their favorable disintegration times and dissolution profiles.

Conclusion: Developed mirtazapine ODTs were found promising in terms of showing the similar characteristics to the original formulation.     

Industrie 4.0

Industry 4.0 – Challenges for constructions of vacuum systems Vacuum systems are finding their way into branches and belonging modern process chains which were hardly in contact with UHV technology in the past. Besides an automatic operation and a flawless processing of parts, vacuum systems and their peripheral devices have to feature options for data output and analysis for subsequent processing in e.g. MES to come up with Industry 4.0 requirements. Subcomponents in vacuum technology partly comply with these requirements in a insufficient way because of their unchanged demands over the last decades. This makes integration into an automatic system more difficult. Despite of that, Industry 4.0 compliant vacuum systems are already producible when there's access to high-level experiences in vacuum and automation technology. This is shown by the examples of residual gas analysis and cleanliness measurement systems and the vacuum bake out oven. A cooperation of vacuum system manufacturers and manufacturers of components is necessary in the future to be able to produce automated vacuum systems in a more efficient way.     

3-<i>epi</i>-bufotalin suppresses the proliferation in colorectal cancer cells through the inhibition of the JAK1/STAT3 signaling pathway

Traditional Chinese medicine (TCM) has been increasingly employed in the last decades in China for both preventing and treating a variety of cancers. 3-epi-bufotalin is an active ingredient of TCM “Chanpi” with anti-tumor potential. However, the effect and mechanism of 3-epi-bufotalin on colorectal cancers were not well disclosed. The present study demonstrated that 3-epi-bufotalin could reduce viability, trigger apoptosis, and block the cell cycle at the G₂/M stage in colorectal cancer cell lines HT29, RKO, and COLO205 in vitro. Moreover, 3-epi-bufotalin inhibited the JAK1/STAT3 signaling pathway. These results indicated the anti-proliferation ability of 3-epi-bufotalin in colorectal cancer cells.     

Production of stable amorphous form by means of spray drying

Spray drying is a very useful method for manufacturing of amorphous solid materials. This is mainly due to the possibility of fast solvent evaporation that leads to a rapid transformation of solution to a solid state. Besides evaporation kinetics, there are various process parameters that influence physical and chemical characteristics of such obtained material. The possibility of obtaining a stable amorphous structure of the active pharmaceutical ingredient in a spray dryer was examined. A solution of the hydrochloride crystalline structure of the active pharmaceutical ingredient in a mixture of water and acetonitrile was dried at different temperatures and flowrates of nitrogen used for atomization, as well as the flowrates of the solution. The influence of the process conditions on the properties of the product was analyzed. The final dried products were characterized and identified with a variety of analytical and physical methods. The results showed that a stable amorphous structure of the high purity active pharmaceutical ingredient is obtained, and that the optimal conditions of the process are defined. The amorphous structure is stable at temperatures below 200°C when it is transformed into a new crystal structure. Conditions of high relative air humidity lead to partial transformation.     

Synthesis and characterization of radiation cross-linked PVP hydrogels and investigation of its potential as an antileishmanial drug carrier

Polymer Bulletin - The aim of this study was to elaborate a suitable hydrogel to be used as drug carrier for antileishmanial treatment. Therefore, a PVP hydrogel was synthesized using gamma...     

CD34⁺ CD38^- subpopulation without CD123 and CD44 is responsible for LSC and correlated with imbalance of immune cell subsets in AML

Acute myeloid leukemia (AML) is regarded as a stem cell disease. However, no one unique marker is expressed on leukemia stem cells (LSC) but not on leukemic blasts nor normal hematopoietic stem cells (HSC). CD34⁺ CD38- with or without CD123 or CD44 subpopulations are immunophenotypically defined as putative LSC fractions in AML. Nevertheless, markers that can be effectively and simply held responsible for the intrinsical heterogeneity of LSC is still unclear. In the present study, we examined the frequency of three different LSC subtypes (CD34⁺ CD38^-, CD34⁺ CD38^- CD123⁺ , CD34⁺ CD38^- CD44⁺ ) in AML at diagnosis. We then validated their prognostic significance on the relevance of spectral features for diagnostic stratification, immune status, induction therapy response, treatment effect maintenance, and long-term survival. In our findings, high proportions of the above three different LSC subtypes were all significantly characterized with low complete remission (CR) rate, high relapse/refractory rate, poor overall survival (OS), frequent FLT3-ITD mutation, the high level of regulatory T cells (Treg) and monocytic myeloid-derived suppressor cells (M-MDSC). However, there was no significant statistical difference in all kinds of other clinical performance among the three different LSC groups. It was demonstrated that CD34⁺ CD38^- subpopulation without CD123 and CD44 might be held responsible for LSC and correlated with an imbalance of immune cell subsets in AML.