Carbon nano-onion composites: Physicochemical characteristics and biological activity

Carbon nano-onion/surfactant (CNO/surfactant) composites offer the possibility to easily produce the soluble nanostructures. That approach combines the hydrophilicity of surfactants with the robustness of carbon structures to produce composites with superior and unusual physicochemical properties. We used the following surfactants: hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100), and polyethylene glycol sorbitan monolaurate (Tween 20) to non-covalently modify CNO surfaces. The existence of stable CNO composites are clearly evidenced by direct transmission electron microscopy observations, which are also supported by thermogravimetric analyses. Dynamic light scattering and zeta potential confirmed their dispersion and stability. Additionally, the biological activity of well-dispersed CNO/surfactant composites against a strain of Escherichia coli was assayed. In vitro antimicrobial assays for the composites revealed that only the CNO/CTAB composite decreased cell viability. This activity could be assigned to the simple composite dissociation in water solutions, however antimicrobial properties of the composite are slightly better when compared with pure CTAB. This indicate some synergic effect with respect to the properties of the pure surfactant.     

Measurement and analysis of the water hammer in ram pump

Sādhanā - This paper presents the results of experimental research of the phenomena occurring in water ram during a single cycle of its operation. Apart from a brief introduction and...     

Insulin-like growth factor I-dependent regulation of prolidase activity in cultured human skin fibroblasts

In metastatic breast cancer the goal to reach must be the best possible palliation with minimum discomfort for the patient. We reviewed our experience with radiotherapy (20 or 30 Gy), systemic therapy and brace. Among 2200 breast cancer patients, we extracted 28 potential candidates for resection. All of them developed new metastases outside the treated field within one year. Local control was achieved in 68%, and 80% of them had stable or better performance status at 3 months. From our analysis, even patients with a so called "solitary lesion" do not seem to have a better prognosis than others. We conclude that radiotherapy (with systemic therapy and a brace) is still first-choice treatment for vertebral metastases; CT-guided percutaneous biopsy can avoid worthless major operations. The role of surgery should be limited to neurological compression, severe mechanical instability and to salvage the failures of conservative treatment.     

NMR study of quaternary superconductor RM2B2C (R = Y,La, Th,and M = Ni,Pd, Pt)

¹⁹⁵Pt-,¹³⁹La- and¹¹B-NMR have been investigated in quaternary RM₂B₂C (R=Y, La, Th and M=Ni, Pd, Pt). The electric quadrupole frequency of¹³⁹La changes more than 5 times in magnitude from M=Ni to Pt, indicating that the hybridization of La-5d and d-electrons of M-element changes largely. The analysis of¹¹B and¹³⁹La spectra shows also the large change of the magnetic anisotropy with R and M element, i.e., _{II c}>_{II ab} in LaNi₂B₂C, but _{II c}>_{II ab} YNi₂B₂C.The data of T₁T and K of¹⁹⁵Pt and¹¹B are consistent with the band effects and with no evidence of strong antiferromagnetic correlation effects.     

Cellular decomposition in Fe-26Ni-(2-3)Ti-Nb steels with an addition of aluminium or molybdenum

Cellular decomposition in three Fe-26Ni-(2-3)Ti-Nb type steels was investigated. One of these steels was alloyed with molybdenum while the two others, differing in grain size, contained an addition of aluminium. In Ni26AITi3Nb and Ni26MoTi2Nb steels quenched from 1223 K in water, the first colonies of decomposition were observed after holding for 4 h at 923 K. A longer holding at this temperature resulted in growth of decomposition cells in the steel with molybdenum while in the steels with aluminium, a halting of the decomposition and the appearance of isolated plates of the phase was observed. In Ni26MoTi2Nb and Ni26Al2Ti3Nb steels, quenched in water and subsequently cold treated in liquid nitrogen, repeated heating in the temperature range 293–999.9 K at a rate of 2.5,10 and 40 Kmin^–1 and cooling at a rate 320 Kmin^–1 favoured the cellular decomposition more markedly in the steel with molybdenum. On cooling to room temperature, austenite within the decomposition cells transformed into martensite. The tendency to cellular decomposition depended to a higher degree on the factors which stabilize austenite as well as on the presence of precipitates in grain boundaries, than on the grain size.     

The effect of anterior lesions to the medial forebrain bundle on the motor activity evoked by a sensory deficit (sensory drive) in rats]

The orbito-frontal cortex and postcommissural MFB lesions evoked two major effects. The first one consisted in an increased need for light stimulation while the second one concerned changes in anxiety level with different results depending on the lesion location (cortical ot subcortical). The second effect is in agreement with P. Simonov's hypothesis concerning the different configurations of the CNS structures. Upon destruction of the orbito-frontal area, the dominant role in behaviour regulation is taken over by the "emotional part" of the brain, whereas the destruction of the postcommissural MFB (reduction of the amygdalar influence on the hypothalamus) creates conditions for functional prevalence of the "informational brain".