Ultra-violet bands of mercury chloride

The Ultra violet bands of mercury chloride have been excited in uncondensed discharge and photographed with a quartz Littrow Spectrograph. The Class II system betweenλ 2900 to 2700 suggested by Wieland as due to the triatomic molecule has been studied in detail. In addition to the bands already recorded by previous investigators, a number of new bands has been recorded in the present investigation. A new vibrational analysis of these bands is given. The entire bands are ascribed to the longer wavelength component of² π-² ?, the other component being the system in the regionλ 2650 to 2400 with a² π interval of 3335 cm^?1 which is in keeping with the corresponding intervals obtained in the case of HgF and Hg I respectively. The following vibrational constants have been determined.Ν _e Ω′ _e Ω″ _e 36346 cm?1 385 cm?1 292.5 cm?1     

Nega-base periodic decimals

Some properties of the periods of prime-reciprocals in a general negative base representation are described.     

Mannich-type C-nucleosidations in the 5,8-diaza-7,9-dicarba-purine family

[structure: see text] C-Nucleosidation with cyclic iminium salts occurring under mild reaction conditions and affording C-nucleosides that are isosteric with N-nucleosides of natural purines is shown to be a consistent property of the entire family of 2,6-(oxo or amino)-disubstituted 5,8-diaza-7,9-dicarba-purines.     

Properly designed modular asymmetric synthesis for enantiopure sulfinamide auxiliaries from N-sulfonyl-1,2,3-oxathiazolidine-2-oxide agents

Simple and practical asymmetric synthesis of functionally differentiated aminoindanol based endo-N-sulfonyl 1,2,3-oxathiazolidine-2-oxide as sulfinyl transfer agents are developed. The importance of these new and unique sulfinyl transfer reagents are exemplified by the expedient production of several sulfinamide ligands, including either enantiomer of (R)-tert-butanesulfinamide in excellent yields and enantiopurities.     

Crystal structure of a B-form DNA duplex containing (L)-alpha-threofuranosyl (3'-->2') nucleosides: a four-carbon sugar is easily accommodated into the backbone of DNA

(L)-alpha-Threofuranosyl-(3'-->2')-oligonucleotides (TNA) containing vicinally connected phosphodiester linkages undergo informational base pairing in an antiparallel strand orientation and are capable of cross-pairing with RNA and DNA. TNA is derived from a sugar containing only four carbon atoms and is one of the simplest potentially natural nucleic acid alternatives investigated thus far in the context of a chemical etiology of nucleic acid structure. Compared to DNA and RNA that contain six covalent bonds per repeating nucleotide unit, TNA contains only five. We have determined the atomic-resolution crystal structure of the B-form DNA duplex [d(CGCGAA)Td(TCGCG)](2) containing a single (L)-alpha-threofuranosyl thymine (T) per strand. In the modified duplex base stacking interactions are practically unchanged relative to the reference DNA structure. The orientations of the backbone at the TNA incorporation sites are slightly altered in order to accommodate fewer atoms and covalent bonds. The conformation of the threose is C4'-exo with the 2'- and 3'-substituents assuming quasi-diaxial orientation.     

A Theory for the Quantitative Estimation of Bed Load Transport Using Radioisotopes

In this paper an attempt has been made to develop a simple theory for the application of radiotracer techniques to estimate the quantum of bed material transported in rivers, estuaries, etc. The emphasis is mainly on the physical concepts involved. Certain assumptyions made in the theory are later verified experimentally.     

An Efficient Computational Framework for the Analysis of Whole Slide Images: Application to Follicular Lymphoma Immunohistochemistry

Follicular Lymphoma (FL) is one of the most common non-Hodgkin Lymphoma in the United States. Diagnosis and grading of FL is based on the review of histopathological tissue sections under a microscope and is influenced by human factors such as fatigue and reader bias. Computer-aided image analysis tools can help improve the accuracy of diagnosis and grading and act as another tool at the pathologist's disposal. Our group has been developing algorithms for identifying follicles in immunohistochemical images. These algorithms have been tested and validated on small images extracted from whole slide images. However, the use of these algorithms for analyzing the entire whole slide image requires significant changes to the processing methodology since the images are relatively large (on the order of 100k × 100k pixels). In this paper we discuss the challenges involved in analyzing whole slide images and propose potential computational methodologies for addressing these challenges. We discuss the use of parallel computing tools on commodity clusters and compare performance of the serial and parallel implementations of our approach.     

Substitution Reactions of Hexachloro γ5-diazadiphosphetidines - First Examples of Hexa(alkoxy)/(aryloxy) Derivatives, [RNP(OR′)3]2

Abstract

The reactions of the hexachloro γ⁵-diazadiphosphetidine, [(MeN)PCl₃]₂ (I) with NaOR′ (R = Ph or CH₂CF₃) lead to the isolation of the hitherto unprecedented hexa-(alkoxy)/(aryloxy) derivatives, [(MeN)P(OR′)₃]₂ (II) which have been characterized by mass spectrometry and NMR (¹H and ³¹P) spectroscopy. The structure of the trifluoroethoxy derivative (II, R′ = CH₂CF₃) has been confirmed by single crystal X-ray analysis. Analogous reactions of the N-phenyl derivative [(PhN)PCl₃]₂ afford only the monophosphazenes, PbN=P(OR′)₃. Aniline reacts with I in a Kirsanov type of reaction accompanied by ring opening to give a bis(phosphineimino)diphosphazane derivative, (PhN=)(NHPh)(NHMe)PN(Me)-P(NHPh)₂(=NPh). The X-ray crystal structure of a related cyclic derivative trans-[PhNP(NMe₂)(=NPh)]₂ has been determined. The N₂P₂ ring and the aryl groups attached to the ring nitrogen atoms are coplanar; the exocyclic P=N bond (151.8 pm) is much shorter than the other P-N bonds (162.5, 169.8 pm).     

Novel effects of localization due to intrinsic disorder in manganites

We discuss the effects of a novel ‘intrinsic’ disorder in hole-doped rare-earth manganites. Using effective field theory as well as direct numerical simulations, we show that this disorder can have dramatic effects in terms of the transition from ferromagnetic insulator to ferromagnetic metal upon hole-doping, including an Anderson localized regime where variable range hopping may be observed.