Grafting onto wool. XI. Graft copolymerization of poly(vinyl acetate) and poly(methyl acrylate) onto reduced wool in presence of potassium persulfate–ferrous ammonium sulfate (KPS—FAS) system as redox initiator

In an attempt to ascertain the role of—SH groups of Himachali wool during graft copolymerization, poly(viny acetate) (PVAc) and poly(methyl acrylate) (PMA) were graft copolymerized onto reduced wool by using potassium persulfate—ferrous ammonium sulfate (KPS—FAS) redox pair in aqueous medium. Reduction of wool was carried out by sodium bisulfite solution of varying concentrations for different reaction periods. Concentration of reducing agent and the extent of reduction were found to influence grafting of vinyl monomers. Maximum grafting of methyl acrylate (MA) and vinyl acetate (VAc) occurred when wool was reduced by 1% and 0.5% NaHSO₃ solution, respectively, for 24 h. Increase in percent grafting of MA onto reduced wool compared to that of unreduced wool has been ascribed to the production of more—SH groups by reduction of—SS—groups of wool fiber.     

Evaluation of segmentation techniques using region area and boundary matching information

Evaluation techniques play an important role while picking a suitable segmentation scheme out of a number of alternatives. In this paper, a novel supervised segmentation evaluation scheme is proposed that is designed by combining segment area and boundary information. Using the evaluation metric, a ranking of the popular segmentation algorithms is carried out. A comparative analysis with existing supervised metrics that are commonly used for grading segmentation schemes is performed. Experimental results indicate that the performance of the proposed measure is promising.     

Atomic scale characterization of ion-induced amorphization of GaAs and InAs using perturbed angular correlation spectroscopy

The perturbed angular correlation technique has been utilized to understand the production and nature of the implantation induced crystalline to amorphous transformation in GaAs and InAs. This technique, which is based upon the nuclear hyperfine interaction of the electric-quadrupole moment of the probe nucleus with the electric field gradient from extra nuclear charges, requires introduction of radioactive probe nuclei in host material. The radioactive probes ¹¹¹In/¹¹¹Cd were produced with the 14UD heavy-ion accelerator via nuclear reaction that recoil implants the ¹¹¹In nuclei deep into single crystals of GaAs (1 0 0) and InAs (1 0 0). After removal of radiation damage, caused by recoil implantation, single crystals of GaAs (1 0 0) and InAs (1 0 0) were implanted with stable ⁷⁴Ge ions (MeV) over a wide dose range at liquid nitrogen temperature. The irradiated samples were investigated with respect to the damage production. The crystalline, disordered and amorphous probe environments were identified from the measurement. The evolution of damage is described within the framework of different amorphization models. In GaAs, amorphization is obtained by direct-impact amorphization and by the growth of amorphous zones due to defect-stimulation at crystalline/amorphous interface. In InAs, the amorphization is first initiated by accumulation of simple point defects and then direct-impact/defect-stimulated mechanism contributes to further stimulate the transformation.     

Studies on structure property correlation of cross‐linked glycidyl azide polymer

Glycidyl azide polymer (GAP) has been evaluated for use as binder for solid propellants. The effects of various parameters like cross‐linking conditions, concentration of crosslinker, and the ratio of isocyanate to hydroxyl functional groups (NCO/OH ratio) on the mechanical properties were studied in detail. It was observed that the type of curing agent and the NCO/OH ratio have a strong influence on the gum‐stock properties. Similar impact was seen for cross‐linker concentration also. The swelling characteristics of the cross‐linked binder prepared with different NCO/OH ratios were evaluated with toluene and tetrahydrofuran (THF). The polarity and the solubility parameter of the solvents were found to influence the swelling of GAP. The NCO/OH ratio and cross‐linker concentration of the polymer were also found to affect the swelling characteristics. The sol fraction determined for the polymer was found to follow a similar pattern. The cross‐link density and average molecular weight between crosslinks (Mc) were determined from the swelling studies and also from the stress–strain relationship. The Mc values were found to be influenced by the NCO/OH ratio. Finally, the Mc values determined from the swelling data were correlated to the gum‐stock properties, and the model parameters were estimated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Discovery of Inhibitors of Trypanosoma brucei by Phenotypic Screening of a Focused Protein Kinase Library

A screen of a focused kinase inhibitor library against Trypanosoma brucei rhodesiense led to the identification of seven series, totaling 121 compounds, which showed >50 % inhibition at 5 μm . Screening of these hits in a T. b. brucei proliferation assay highlighted three compounds with a 1H‐imidazo[4,5‐b]pyrazin‐2(3H)‐one scaffold that showed sub‐micromolar activity and excellent selectivity against the MRC5 cell line. Subsequent rounds of optimisation led to the identification of compounds that exhibited good in vitro drug metabolism and pharmacokinetics (DMPK) properties, although in general this series suffered from poor solubility. A scaffold‐hopping exercise led to the identification of a 1H‐pyrazolo[3,4‐b]pyridine scaffold, which retained potency. A number of examples were assessed in a T. b. brucei growth assay, which could differentiate static and cidal action. Compounds from the 1H‐imidazo[4,5‐b]pyrazin‐2(3H)‐one series were found to be either static or growth‐slowing and not cidal. Compounds with the 1H‐pyrazolo[3,4‐b]pyridine scaffold were found to be cidal and showed an unusual biphasic nature in this assay, suggesting they act by at least two mechanisms.     

Walking dynamics are symmetric (enough)

Many biological phenomena such as locomotion, circadian cycles and breathing are rhythmic in nature and can be modelled as rhythmic dynamical systems. Dynamical systems modelling often involves neglecting certain characteristics of a physical system as a modelling convenience. For example, human locomotion is frequently treated as symmetric about the sagittal plane. In this work, we test this assumption by examining human walking dynamics around the steady state (limit-cycle). Here, we adapt statistical cross-validation in order to examine whether there are statistically significant asymmetries and, even if so, test the consequences of assuming bilateral symmetry anyway. Indeed, we identify significant asymmetries in the dynamics of human walking, but nevertheless show that ignoring these asymmetries results in a more consistent and predictive model. In general, neglecting evident characteristics of a system can be more than a modelling convenience—it can produce a better model.     

Intraoperative mitomycin C in complicated glaucomas

Filtering surgery has been found to be less successful in certain types of glaucoma. These include young patients, those with pigmentary glaucoma, secondary glaucoma, angle recession glaucoma, aphakic or pseudophakic glaucoma, and patients requiring reoperation. This study describes the authors' attempt to evaluate the effectiveness of conventional trabeculectomy with intraoperative application of mitomycin C in such patients. Ten eyes of 8 patients were evaluated in this study. Of these cases 4 eyes (2 bilateral cases) were from the primary juvenile open angle group; 2 eyes each had pseudophakic glaucoma and previous anti-glaucoma surgery which had failed; one eye had aphakic glaucoma and the last suffered from angle recession glaucoma. The intraocular pressure was successfully controlled in all the ten eyes. The preoperative IOP ranged from 28 to 50 mm Hg and the postoperative IOP ranged from 7 to 16 mm Hg. The postoperative complications were minimal.     

A scenario-based verification technique to assess the compatibility of collaborative business processes

Successful E-Business is based on seamless collaborative business processes. Each partner in the collaboration specifies its own rules and interaction preconditions. The verification of the compatibility of collaborative business processes, based on local and global views, is a complex task, which is critical for the success of the cooperation. The verification of process compatibility should be a key element in the design of new business alliances, which makes this verification essential in inter-organizational business process design. The advent of Web Services and Service Oriented Architectures stresses the need to solve complex business cooperations under the pressure of reduced costs and risks, combined with shorter time to market. At the same time, the message-based paradigm results in large and complex processes which makes the verification process quite hard.First the use of an atomic business activity based interaction paradigm is proposed to reduce the complexity of collaborative process models. Next, formal compatibility criteria for business processes are developed. The key construction is the notion of semantic compatibility, which can be used to assess the compatibility of the publicly exposed behavior (a.k.a. business interfaces) between business partners in joint business processes. The formal nature of this compatibility allows to give a precise indication of the degree of compatibility between cooperating business partners. It enables exhaustive lists of incompatible (i.e. unsupported scenarios) business cooperations, which is more comprehensive and complete than the typical compatible or incompatible answer to this question. Finally, complex multiple party interactions can be examined in terms of the safety of the interaction protocols.     

CHOOSE: Towards a metamodel for enterprise architecture in small and medium-sized enterprises

Enterprise architecture (EA) is a coherent whole of principles, methods, and models that are used in the design and realization of an enterprise’s organizational structure, business processes, information systems, and IT infrastructure. Recent research indicates the need for EA in small and medium-sized enterprises (SMEs), important drivers of the economy, as they struggle with problems related to a lack of structure and overview of their business. However, existing EA frameworks are perceived as too complex and, to date, none of the EA approaches are sufficiently adapted to the SME context. Therefore, this paper presents the CHOOSE metamodel for EA in SMEs that was developed and evaluated through action research in an SME and further refined and validated through case study research in five other SMEs. This metamodel is based on the essential dimensions of EA frameworks and is kept simple so that it may be applied in an SME context. The final CHOOSE metamodel includes only four essential concepts (i.e. goal, actor, operation, object), one for each most frequently used EA focus. As an example, an extract is included from the specific model that was created for the SME used in our action research. Finally, the CHOOSE metamodel is evaluated according to the dimensions essential in EA and the requirements for EA in an SME context.