Influence of end-group modification on interaction of amphiphilic poly(oxyethylene)-<Emphasis Type="Italic">b</Emphasis>-poly(oxybutylene) block copolymers with ionic surfactants

Amphiphilic poly(oxyethylene)-b-poly(oxybutylene) block copolymers having hydrophilic block end-capped with neutral dimethylamino (DE₇₉B₃₄) and cationic trimethyl ammonium (TE₇₉B₃₄) groups, respectively were investigated for their interactions with ionic surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) using tensiometry, conductometry and dynamic light scattering. The self-assembly of DE₇₉B₃₄ and TE₇₉B₃₄ occur at 0.7 g/dm³ and 0.8 g/dm³, respectively. TE₇₉B₃₄ binds favorably with oppositely charged SDS, causing a substantial change in surface tension compared to other surfactant-polymer systems. In mixed polymer-surfactant systems, the micellization was promoted in the presence of SDS, but it was suppressed with CTAB. Such behavior is expected for cationic block copolymers, since they can engage into ion-pair formation with anionic SDS. For neutral polymers, the behavior is reflective of surfactants’ head group hydrophobicity. The head groups of CTAB are more hydrophobic and their existence in the proximity of hydrophobic segments of polymers induces shape transition to non-spherical morphologies. Gibb’s free energy of adsorption at air – water interface is negative for SDS, CTAB and surfactant-block copolymer systems, indicating that the process is highly spontaneous. The increase in entropy of TE₇₉B₃₄ during micelle formation with temperature is due to disturbance of hydrophobic structure of water molecules, thus hydrophobic parts are removed from bulk solution to the interface and also in the interior of micelle the freedom of hydrophobic part is increased. The dynamic laser light scattering results revealed that due to presence of block copolymers pre-micellar aggregates were favored.     

Synthesis and Characterization of Rutile TiO2 Nanopowders Doped with Iron Ions

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5–7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO₂ into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence.     

Continuous mixing of powder mixtures with pharmaceutical process constraints

While it would provide many advantages from many aspects, the application of continuous mixing processes to the pharmaceutical field is still in its infancy. In this paper we report results concerning the continuous mixing of nine ingredients (including three actives) that constitute a current drug. We examine these results in the light of different pharmaceutical process constraints, such as mixture quality control, time-stability of this quality, sensitivity of the process to perturbations. The apparatus is a pilot plant Gericke GCM 500 continuous mixer with three loss-in-weight feeders. A specific experimental protocol is developed to determine the homogeneity of the mixtures at the outlet of the mixer. The homogeneity of the mixtures is examined through industrial standards that would allow the product to be released on the market. The steady-state operation is first reported on, and it is demonstrated that a very acceptable mixture can be produced under certain conditions, with excellent time stability. The response of the mixer to filling sequences of two critical feeders is also quantified in terms of mixture homogeneity. It is found that it may be preferable to stop the process during these periods.     

Loss of ZNF677 Expression Is an Independent Predictor for Distant Metastasis in Middle Eastern Papillary Thyroid Carcinoma Patients

Thyroid cancer incidence has increased in recent decades. Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Approximately 30% of PTC patients develop recurrence or distant metastasis and tend to have poor prognosis. Therefore, the identification of targetable biomarkers in this subset of patients is of great importance. Accumulating evidence indicates that zinc finger protein 677 (ZNF677), which belongs to the zinc finger protein family, is an important effector during the progression of multiple malignancies. However, its role in Middle Eastern PTC patients has not been fully illustrated. Here, we uncovered the molecular mechanism and the clinical impact of ZNF677 expression in a large cohort of more than 1200 Middle Eastern PTC and 15 metastatic tissues. We demonstrated that ZNF677 is frequently downregulated in primary PTC (13.6%, 168/1235) and showed that complete loss of expression of ZNF677 is significantly associated with aggressive clinico-pathological markers such as extrathyroidal extension (p = 0.0008) and distant metastases (p < 0.0001). We also found a significantly higher incidence of ZNF677 loss in primary tumors with distant metastases (33.3%; p < 0.0001) as well as in distant metastatic tissues (46.7%; p = 0.0002) compared to the overall cohort (13.6%). More importantly, PTC with loss of ZNF677 expression showed significantly lower metastasis-free survival (p = 0.0090). Interestingly, on multivariate logistic regression analysis, ZNF677 loss was an independent predictor of distant metastasis in PTC (Odds ratio = 2.60, 95% Confidence interval = 1.20–5.62, p = 0.0155). In addition, we found a significant association between ZNF677 loss and phospho-AKT expression (p < 0.0001). Our functional molecular results suggest that ZNF677 acts as a tumor suppressor, mediating its effect by inhibiting AKT phosphorylation. Taken together, our results highlight the pivotal role played by ZNF677 during carcinogenesis and metastasis formation in Middle Eastern PTC patients.     

Nature-inspired heuristic paradigms for parameter estimation of control autoregressive moving average systems

Neural Computing and Applications - Aim of this research is to explore the strength of evolutionary and swarm intelligence techniques for parameter identification of control autoregressive moving...     

Mobile cloud based-framework for sports applications

Multidimensional Systems and Signal Processing - Smartphones are increasingly becoming popular due to the wide range of capabilities, such as Wi-Fi connectivity, video acquisition, and navigation....     

Investigation of the antibacterial activity and efflux pump inhibitory effect of co-loaded piperine and gentamicin nanoliposomes in methicillin-resistant Staphylococcus aureus

Objective: Antibiotic resistance has stimulated the research for developing novel strategies that can prevent bacterial growth. Methicillin-resistant Staphylococcus aureus (MRSA), regarded as one of the most serious antibiotic-resistant bacteria which has been conventionally recognized as a nosocomial pathogen.

Materials and methods: Nanoliposomal formulations of piperine and gentamicin were prepared by dehydration-rehydration (DRV) method and characterized for size, zeta potential and encapsulation efficiency. Antibactericidal activities of liposomal and free forms were evaluated against MRSA ATCC 43300 by the determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and fractional inhibitory concentration index (FICI). The time-kill studies were carried out to evaluate the potency of antibacterial agents. The effect of piperine on bacterial efflux pumps was also investigated.

Results: MIC values of gentamicin and piperine were 32 and 100?µg/mL, respectively. Synergetic effects were observed by the combination of gentamicin and piperine and FICI was determined to be 0.5. Following incorporation of gentamicin into liposomal gentamicin and liposomal combination, the MIC values were reduced 16- and 32-fold, respectively. MBC values of gentamicin reduced 4 and 8 times following incorporation into gentamicin and combination liposomes, respectively. In comparison with vancomycin, liposomal combination was more effective in bacterial inhibition and killing. Liposomal combination was the most effective preparations in time-kill study. Our findings indicated that liposomal piperine was able to inhibit the efflux pump sufficiently.

Conclusion: The results of this study revealed that liposomal combination is a powerful nano-antibacterial agent to eradicate MRSA infection. This dual-loaded formulation was an effective approach for eradication of MRSA.     

采空区下近距离煤层巷道围岩稳定性分析及控制

针对近距离煤层工况条件下,下部特厚综放工作面开采时存在覆岩应力变化大、矿压显现明显、工作面支护难度加大,煤壁片帮、顶板漏冒事故多等问题,以王庄煤矿开采的2号和3-5号煤层工作面为工程背景,通过理论分析、采用UDEC离散元软件和FLAC 3D软件建模分析及现场应用实践等方法,对近距离特厚煤层开采条件下工作面采空区覆岩运动及顶板应力变化规律进行了研究分析。结果表明,上部2号已开采煤层覆岩关键层岩体发生断裂对下部3-5号煤层工作面来压强度影响巨大,容易引发工作面采空区顶板大面积来压。据此提出优化30501工作面巷道布置,将原回风巷向内侧偏移25.4 m,工作面倾斜长由原来的180 m缩短为154.6 m,从而减小上部煤层工作面留设的区段煤柱应力影响范围,同时通过优化工作面开采工艺、合理确定工作面三机设备选型和端头及超前支护方案。现场应用结果表明,工作面在掘进和回采过程中矿压显现程度及次数明显降低和减少,未发生过顶板、瓦斯等大型事故,实现了安全高效回采。