A modified electron bombardment type ion source for the study of solids

A modified electron bombardment type ion source suitable for use with mass spectrometer is described. Ion formation occurs throughout a relatively large volume in the ionisation box, since no magnetic field is used to collimate the ionising electrons. A sensitivity of 2 × 10⁻⁵ amp/torr is obtained for an ion extraction energy of 2 keV and 200 mass resolution. Trajectory tracing has been used to study the operation of the ion source. Capability of the ion source to analyse solid samples in microgram quantity was tested by studying evaporation of BaO from tungsten.     

Ultrasound promoted asymmetric transfer hydrogenation of ketones using Ru(II)arene/amino alcohol catalyst system

Asymmetric transfer hydrogenation of ketones using Ru(II)arene/amino alcohol catalyst system proceeds with significant rate enhancement by ultrasound promotion. Comparison of the silent reactions carried out at 25 degrees C with reactions under sonochemical activation at 25 degrees C clearly showed enhancement in catalytic activity by 5-10 times without significantly affecting the enantioselectivity.     

An Efficient One‐pot Three‐component Method for the Synthesis of 5‐Amino‐3‐(2‐oxo‐2H‐chromen‐3‐yl)‐7‐aryl‐7H‐thiazolo[3,2‐a]pyridine‐6,8‐dicarbonitriles

A facile, convenient, and adequate method has been developed for the synthesis of novel 5‐amino‐3‐(2‐oxo‐2H‐chromen‐3‐yl)‐7‐aryl‐7H‐thiazolo[3,2‐a]pyridine‐6,8‐dicarbonitriles ( 6 ) by employing 2‐(4‐(2‐oxo‐2H‐chromen‐3‐yl)thiazol‐2‐yl)acetonitrile ( 3 ) as an important precursor. Initially, we have synthesized the target compounds in a stepwise manner and then approached a tandem method to examine the feasibility of one‐pot method. Subsequently, one‐pot three‐component protocol has been established for the synthesis of title compounds by the reaction of 3 with benzaldehyde and malononitrile in refluxing ethanol engender a new six‐membered thiazolo[3,2‐a] pyridine as a hybrid scaffold. Reaction conditions were optimized for this reaction and a broad substrate scope with various aryl and heteroaryl aldehydes make this protocol very practical, attractive, and worthy. Mechanistic aspects for the formation of these compounds were outlined comprehensively. Characterization of these newly synthesized compounds was achieved by means of IR, ¹H NMR, ¹³C NMR, and HRMS.     

Synthesis,Characterization, Molecular Docking,and Antimicrobial Activity of New Arylidene-Substituted Imidazoles

Russian Journal of General Chemistry - The title compounds are synthesized by condensation of 2-[4-(arylidene)-5-oxo-4, 5-dihydrooxazol-2-yl]phenylacetate with aromatic amines in presence of the...     

An efficient one-pot three-component synthesis of 2-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)-3-arylacrylonitriles and their cytotoxic activity evaluation with molecular docking

A facile, convenient and one-pot three-component method has been outlined for the synthesis of title compounds by treating equimolar amounts of 3-(2-bromoacetyl)-2H-chromen-2-one (2) with 2-cyanothioacetamide (3) and various aryl/heteryl aldehydes (5 or 7) independently. The effect of solvent and catalyst on this one-pot reaction has been studied and the use of l-proline in ethanol was found to be effective to achieve the target compounds (6 & 8) in fair yields. These synthesized compounds were further assessed for the anti-hepatoma activity, and their action mechanism was also investigated by using molecular docking studies. All the compounds 6(a-h) & 8(a-f) manifested excellent potency for anti-hepatoma activity. It should be noted that, compounds 6e, 6f have exhibited almost equipotent activity with reference to standard drug Nexavar.     

Efficient electrode material for electrochemical energy storage from organic waste

Journal of Solid State Electrochemistry - Heteroatom functionalities in activated carbons have a positive effect on their electrochemical properties. High surface area, reasonable heteroatom...     

Correlation between photophysical properties and lasing performances of Rhodamine-19 in three types of sol–gel glass hosts

Rhodamine-19 (Rh-19) incorporated three types of sol–gel samples (mentioned as dope route-I, dope route-II and dip method) were prepared by using two different methods of dye impregnation. The photophysical properties of all the three types of Rh-19 incorporated sol–gel solids were studied by using the UV–Visible absorption and the fluorescence spectroscopy. A single photon counting technique was used to estimate the lifetime of fluorescent species. From the study of fluorescence spectra, the coexistence of dimers (fluorescent and non-fluorescent both) and monomer of Rh-19 was observed. The photophysical properties of Rh-19 were found to be the best in dip sample, medium in dope route-II sample and low in dope route-I sample. After studying photophysical properties, the samples were subjected to laser study under nitrogen laser pumping at 337.1 nm at the rate of 1.5 Hz in transverse dye laser cavity. The highest laser efficiency and photostability of the dye were observed in dip sample, medium in dope route-II sample and small in dope route-I sample. A comparison between photophysical properties and laser performance of these materials showed a very good correlation.     

Comparison of tumor histology to dynamic contrast enhanced magnetic resonance imaging-based physiological estimates

Purpose

The purpose of this study was to compare histologically determined cellularity and extracellular space to dynamic contrast-enhanced magnetic resonance imaging (DCE MRI)-based maps of a two-compartment model's parameters describing tumor contrast agent extravasation, specifically tumor extravascular extracellular space (EES) volume fraction (v_e), tumor plasma volume fraction (v_p) and volume-normalized contrast agent transfer rate between tumor plasma and interstitium (K_TRANS/V_T).

Materials and Methods

Obtained v_e, v_p and K_TRANS/V_T maps were estimated from gadolinium diethylenetriamine penta-acetic acid DCE T₁-weighted gradient-echo images at resolutions of 469, 938 and 2500 μm. These parameter maps were compared at each resolution to histologically determined tumor type, and the high-resolution 469-μm maps were compared with automated cell counting using Otsu's method and a color-thresholding method for estimated intracellular (V_{intracellular}) and extracellular (V_{extracellular}) space fractions.

Results

The top five K_TRANS/V_T values obtained from each tumor at 469 and 938 μm resolutions are significantly different from those obtained at 2500 μm (P<.0001) and from one another (P=.0014). Using these top five K_TRANS/V_T values and the corresponding tumor EES volume fractions v_e, we can statistically differentiate invasive ductal carcinomas from noninvasive papillary carcinomas for the 469- and 938-μm resolutions (P=.0017 and P=.0047, respectively), but not for the 2500-μm resolution (P=.9008). The color-thresholding method demonstrated that v_e measured by DCE MRI is statistically similar to histologically determined EES. The V_{extracellular} obtained from the color-thresholding method was statistically similar to the v_e measured with DCE MRI for the top 10 K_TRANS/V_T values (P>.05). DCE MRI-based K_TRANS/V_T estimates are not statistically correlated with histologically determined cellularity.

Conclusion

DCE MRI estimates of tumor physiology are a limited representation of tumor histological features. Extracellular spaces measured by both DCE MRI and microscopic analysis are statistically similar. Tumor typing by DCE MRI is spatial resolution dependent, as lower resolutions average out contributions to voxel-based estimates of K_TRANS/V_T. Thus, an appropriate resolution window is essential for DCE MRI tumor diagnosis. Within this resolution window, the top K_TRANS/V_T values with corresponding v_e are diagnostic for the tumor types analyzed in this study.