Intramolecular Charge Transfer aromatic amines and their application towards molecular logic gate

The emission response of 1-aminopyrene and 2-aminoanthracene was found to be switched ON or OFF by interrupting the Intramolecular Charge Transfer processes of these integrated systems using two binary ionic inputs like H⁺ or/and OH⁻. These fluorescence responses in the presence of added H⁺ or/and OH⁻ could be correlated with Half-subtractor logic operation, revealing the possibility of using simple molecules for demonstrating complex logic operations.     

Loss of plasma membrane lipid asymmetry can induce ordered domain (raft) formation

In some cases, lipids in one leaflet of an asymmetric artificial lipid vesicle suppress the formation of ordered lipid domains (rafts) in the opposing leaflet. Whether this occurs in natural membranes is unknown. Here, we investigated this issue using plasma membrane vesicles (PMVs) from rat leukemia RBL-2H3 cells. Membrane domain formation and order was assessed by fluorescence resonance energy transfer and fluorescence anisotropy. We found that ordered domains in PMVs prepared from cells by N-ethyl maleimide (NEM) treatment formed up to ～37°C, whereas ordered domains in symmetric vesicles formed from the extracted PMV lipids were stable up to 55°C, indicating the stability of ordered domains was substantially decreased in intact PMVs. This behavior paralleled lesser ordered domain stability in artificial asymmetric lipid vesicles relative to the corresponding symmetric vesicles, suggesting intact PMVs exhibit some degree of lipid asymmetry. This was supported by phosphatidylserine mislocalization on PMV outer leaflets as judged by annexin binding, which indicated NEM-induced PMVs are much more asymmetric than PMVs formed by dithiothreitol/paraformaldehyde treatment. Destroying asymmetry by reconstitution of PMVs using detergent dilution also showed stabilization of domain formation, even though membrane proteins remained associated with reconstituted vesicles. Similar domain stabilization was observed in artificial asymmetric lipid vesicles after destroying asymmetry via detergent reconstitution. Proteinase K digestion of proteins had little effect on domain stability in NEM PMVs. We conclude that loss of PMV lipid asymmetry can induce ordered domain formation. The dynamic control of lipid asymmetry in cells may regulate domain formation in plasma membranes.     

Detection of disease specific sialoglycoconjugate specific antibodies in bronchoalveolar lavage fluid of non-small cell lung cancer patients

In this study, we report the presence of significantly higher level of GM3 specific IgG antibodies (IgG_TL) in the bronchoalveolar lavage fluid obtained from tumor bearing lung of non-small cell lung cancer (NSCLC) patients as compared to other non-neoplastic controls. The antibodies were isolated using DEAE-cellulose anion exchange chromatography and molecular weight of the subunits of IgG_TL was confirmed in SDS-PAGE. IgG_TL revealed high specificity to GM3 and the IgG distribution was confined to IgG1. Furthermore, IgG_TL showed strong reactivity with NSCLC cell lines as well as the tissue biopsies and cells obtained from fine needle aspirations of NSCLC patients. A 66 kDa membrane glycoprotein of NSCLC cell lines was found to interact specifically with IgG_TL, the intensity of which was drastically reduced in presence of GM3. Further, binding of Maackia amurensis agglutinin [specific for NeuAcα(2→3)Gal unit , the same disaccharide unit also known to be present in GM3] to the 66 kDa band confirmed it to be a sialoglycoprotein in nature. IgG_TL could not show any reactivity to alkaline borohydrate treated or periodate oxidised membrane fractions, suggesting the probable involvement of the carbohydrate moiety of the 66 kDa glycoprotein in the interaction with IgG_TL. Thus, the 66 kDa sialoglycoprotein seems to be the NSCLC specific sialoglycoconjugate. Taken together, IgG_TL antibodies may have the potential to serve as a unique probe for detail investigation of NSCLC specific cell surface sialoglycoconjugate. Further, due to high specificity of IgG_TL to GM3, it may be possible to develop a simple alternative diagnostic approach (GM3-ELISA) for NSCLC.     

Infrared-spectral characteristics of some acetylated,anomeric glycosides

Barker and co-workers had described the C-1-H deformation bands in the ranges 844 ±8 cm^?1 and 891 ±7 cm^?1 as characteristic bands for the α and β anomers, respectively, of hexo- and pento-pyranoses and -pyranosides, and their derivatives. Later, Audichya and co-workers reported the presence of the 844 ±8-cm^?1 band for both anomers of some aryl d-glucoside derivatives, making the applicability of the earlier findings doubtful. Examination by us of the i.r. spectra of some aryl glycoside derivatives suggested that the origin of the band at 844 ±8 cm^?1 for the β anomers of the p-substituted-aryl glycoside derivatives studied by Audichya et al. could be a CH, out-of-plane deformation-mode of the substituted aromatic ring. Also, their further claim of a characteristic band in the region 961-957 cm^?1 for α anomers is shown to be of little diagnostic value. The relative intensities of bands in the COC stretching region, 1100-1000 cm^?1, and a band near 300 cm^?1 in the COC deformation region, found only for the β anomers, are shown to be helpful in differentiating the anomers of some peracetylated alkyl and aryl glycosides.     

Nonlinear Elastic and Viscoelastic Deformation of the Human Red Blood Cell with Optical Tweezers

Studies of the deformation characteristics of single biological cells can offer insights into the connections among mechanical state, biochemical response and the onset and progression of diseases. Deformation imposed by optical tweezers provides a useful means for the study of single cell mechanics under a variety of well-controlled stress-states. In this paper, we first critically review recent advances in the study of single cell mechanics employing the optical tweezers method, and assess its significance and limitations in comparison to other experimental tools. We then present new experimental and computational results on shape evolution, force--extension curves, elastic properties and viscoelastic response of human red blood cells subjected to large elastic deformation using optical tweezers. Potential applications of the methods examined here to study diseased cells are also briefly addressed.     

A note on the yeast flora associated with fermentation of mango

Fifteen morphologically different groups of yeasts consisting of Metschnikowia pulcherrima, Trichosporon cutaneum, Kloeckera apiculata, Torulopsis Candida, Tor. glabrata. Tor. apicola, Candida tropicalis, Cand. krusei, Cand. sorbosa, Cand. diversa, Pichia terricola, Pic. membranaefaciens, Hyphopichia burtonii, Rhodotorula graminis and Aureobasidium pullulans were isolated from fresh, fermenting and fermented juice of two varieties of mango. This is the first report on the study of yeast flora of mango and also on the occurrence of Hyp. burtonii on fruits.     

The susceptibility to ultrasonic disintegration ofKlebsiella pneumoniae NCTC 418

Summary The resistance to ultrasonic disintegration of cells ofKlebsiella pneumoniae grown at various dilution rates in continuous culture decreased with increasing cell size. Whilst this effect could be related to the cell wall content of the specimens, no direct relationship between the cell wall strength and the rigidity-conferring peptidoglycan was observed.     

Immunoassay for honey bee cytochrome c in single animals with cytochrome c-coated bacteriophages: A sensitive tool for the study of caste formation in the honey bee, Apis Mellifera

The development of a sensitive viroimmunoassay for honey bee cytochrome $\text{c}$ and its usage for early detection of caste differentiation is described. Pure honey bee cytochrome $\text{c}$ was isolated from workers and used to produce antibodies in rabbits. Bacteriophage T4 was chemically modified by covalent attachment of honey bee cytochrome $\text{c}$ using tolylene-2,4-diisocyanate as a cross-linking agent. The immunospecific inactivation of this bacteriophage-cytochrome c conjugate by anti-cytochrome $\text{c}$ antibodies can be inhibited by free cytochrome $\text{c}$. In quantitative determinations, 50% inhibition is reproducibly achieved at a concentration of 6 ng/ml (5 pmol/ml) and as little as 0.3 ng/ml (0.25 pmol/ml) could be detected by this system. Cytochrome $\text{c}$ concentrations were measured in individual animals and substantial differences between corresponding larval stages of worker and queen bees are reported.     

Parallel FFT on ATM‐based networks of workstations

We consider parallel computing on a network of workstations using a connection-oriented protocol (e.g., Asynchronous Transfer Mode) for data communication. In a connection-oriented protocol, a virtual circuit of guaranteed bandwidth is established for each pair of communicating workstations. Since all virtual circuits do not have the same guaranteed bandwidth, a parallel application must deal with the unequal bandwidths between workstations. Since most works in the design of parallel algorithms assume equal bandwidths on all the communication links, they often do not perform well when executed on networks of workstations using connection-oriented protocols. In this paper, we first evaluate the performance degradation caused by unequal bandwidths on the execution of conventional parallel algorithms such as the fast Fourier transform and bitonic sort. We then present a strategy based on dynamic redistribution of data points to reduce the bottlenecks caused by unequal bandwidths. We also extend this strategy to deal with processor heterogeneity. Using analysis and simulation we show that there is a considerable reduction in the runtime if the proposed redistribution strategy is adopted. The basic idea presented in this paper can also be used to improve the runtimes of other parallel applications in connection-oriented environments. This revised version was published online in July 2006 with corrections to the Cover Date.     

Multicast scheduling algorithms in mobile networks

We consider the problem of multicasting data to mobile users in a cellular mobile network. In the absence of mobility, a single channel can be used to multicast to all mobile users within a cell. However, mobility combined with the effects of fading necessitates a more complex channel allocation policy. In this paper we develop theoretical bounds on the maximum obtainable efficiency and present algorithms that acheive this bound. Our results hold for the case when mobiles travel on a highway, as well as for the more general case where mobiles roam in a two-dimensional region. This revised version was published online in August 2006 with corrections to the Cover Date.