Multi-objective path planning for lung biopsy surgery

Multimedia Tools and Applications - CT image-guided lung biopsy surgery is the gold standard for lung tumor diagnosis. The preoperative path planning of the surgery is necessary, which aims to find...     

Full-program induction: verifying array programs sans loop invariants

International Journal on Software Tools for Technology Transfer - Arrays are commonly used in a variety of software to store and process data in loops. Automatically proving safety properties of...     

Child–smartphone interaction: relevance and positive and negative implications

Universal Access in the Information Society - An increasing number of children are now using smartphones, and the phenomenon is being studied keenly by computer scientists, pediatricians,...     

Solvothermal Synthesis,Cathodoluminescence, and Field‐Emission Properties of Pure and N‐Doped ZnO Nanobullets

Homogenous crystallization in solution, in the absence of external influences, is expected to lead to growth that is symmetric at least in two opposite facets. Such was not the case when we attempted to synthesize ZnO nanostructures by employing a solvothermal technique. The reaction product, instead, consisted of bullet‐shaped tiny single crystals with an abrupt hexagonal base and a sharp tip. A careful analysis of the product and the intermediate states of the synthesis reveals that one of the reaction intermediates with sheet‐like morphology acts as a self‐sacrificing template and induces such unexpected and novel growth. The synthesis was further extended to dope the nanobullets with nitrogen as previous studies showed this can induce p‐type behavior in ZnO, which is technologically complementary to the naturally occurring n‐type ZnO. Herein, a soft‐chemical approach is used for the first time for this purpose, which is otherwise accomplished with high‐temperature techniques. Cathodoluminesce (CL) investigations reveal stable optical behavior within a pure nanobullet. On the other hand, the CL spectra derived from the surfaces and the cores of the doped samples are different, pointing at a N‐rich core. Finally, even though N‐doped ZnO is known to have high electrical conductivity, the study now demonstrates that the field‐emission properties of ZnO can also be greatly enhanced by means of N doping.     

Loss of structural integrity and hydrophobic ligand binding capacity of acetylated and succinylated bovine β-lactoglobulin

The lysine residues of bovine β-lactoglobulin (β-lg) were acetylated and succinylated to investigate the effect of chemical modification on tertiary and secondary structures. Both derivatives showed higher electrophoretic mobility compared with native β-lg. The molar extinction coefficients of modified proteins were lower than native β-lg. A significant decrease in intrinsic tryptophan fluorescence intensities, and a red shift of emission maxima were observed. The structural stabilities of the derivatives were compared with the native form. Both modified β-lg structures were less stable against guanidine hydrochloride and urea denaturation. Hydrophobicities decreased, as measured by hydrophobic ligand binding of the modified β-lg. Circular dichroism spectra of modified forms were different. The beta structural content of modified β-lactoglobulins decreased substantially with an increase in random coil structure. These modifications changed the tertiary structure, and involved a significant loss of secondary structure of β-lg.     

Adsorption study of hexavalent chromium using tamarind hull-based adsorbents

The adsorption characteristics of hexavalent chromium was studied with an adsorbent developed from waste tamarind hull. Experiments were conducted in batch mode to observe the influence of different parameters such as initial concentration of metal ions, adsorbent dosage, adsorbent particle size, stirrer speed, temperature and pH of the solution. Acidic pH strongly favored the adsorption. With decreasing the pH of the solution from 5.0 to 1.0, the removal of chromium was enhanced from 33% to 99%. The adsorption process was found to follow a pseudo-first-order rate mechanism and the rate constant was evaluated at 30 °C. The Freundlich, Redlich–Peterson and the Fritz–Schlunder isotherm fit the equilibrium data satisfactorily. Adsorption of chromium was found to increase with increase in the process temperature. Using an adsorbent dosage of 1.0 g/L and an acidic pH (2.0), the equilibrium adsorption capacity of the prepared adsorbent was found to be about 70 mg/g at 30 °C, which increased to about 81 mg/g at 50 °C. The entropy change, free energy change and heats of adsorption were determined for the process.     

An intermediate-layer lithography method for generating multiple microstructures made of different conducting polymers

An intermediate-layer lithography (ILL) method has been developed in this work to generate multiple microstructures of different conducting polymers on the same substrate. Previous and current efforts in developing conducting polymer microsystems mainly focus on generating a device of a single function. When multiple micropatterns of different conducting polymers are produced on the same substrate, many microsystems of multiple functions can be envisioned. However, existing techniques present significant technical challenges of degradation, low throughput, low resolution, depth of field, and/or residual layer in producing conducting polymer microstructures. To circumvent these challenges, the ILL method has been explored to generate multiple micropatterns of different conducting polymers in a parallel manner. In this method, conducting polymer materials and a non-conducting polymer intermediate layer are first coated on a substrate, and are then patterned through a mold insertion at a raised temperature. In this work, the ILL has been used to successfully pattern three types of commonly used conducting polymers on the same substrate under a single mold insertion, and simulation has been conducted to gain a good understanding of the molding process. Due to distinctive advantages of simplicity, low cost and high throughput, the ILL has promising applications in fabricating micropatterns for polymer-based microsystems.     

An effort to fabricate and characterize in-situ formed graded structure in a ceramic-metal system

Monolithic alumina and alumina–silver composite containing 15.0 vol.% of silver have been fabricated via pressureless sintering approach. By virtue of the inherent high vapour pressure of silver at elevated temperature during sintering, a decreasing silver gradient was observed between the bulk and the surface of the composite material. As a consequence of this phenomenon, a functionally graded structure of alumina–silver could be observed having the core rich in silver (in alumina matrix) and the surface rich in mostly alumina. Hardness and fracture toughness data evaluation reveals the fact that the surface of the composite specimen has higher hardness and lower fracture toughness due to lesser silver content, whereas, the core (bulk) of the sample has higher fracture toughness and lower hardness due to higher silver content. This kind of graded structure could be ideal as a cutting tool or wear-resistant material, which demands a harder surface (for machining) followed by a tougher core (for flaw-tolerance). Both the flexural strength and fracture toughness values of alumina are observed to improve with incorporation of silver and the associated potential strengthening and toughening mechanisms are identified in relation with the observed microstructural features.     

Cache-aware optimization of BAN applications

Body-area sensor network or BAN-based health monitoring is increasingly becoming a popular alternative to traditional wired bio-monitoring techniques. However, most biomonitoring applications need continuous processing of large volumes of data, as a result of which both power consumption and computation bandwidth turn out to be serious constraints for sensor network platforms. This has resulted in a lot of recent interest in design methods, modeling and software analysis techniques specifically targeted towards BANs and applications running on them. In this paper we show that appropriate optimization of the application running on the communication gateway of a wireless BAN and accurate modeling of the microarchitectural details of the gateway processor can lead to significantly better resource usage and power savings. In particular, we propose a method for deriving the optimal order in which the different sensors feeding the gateway processor should be sampled, to maximize cache reuse. In addition, we also investigate the effects on cache reuse of different memory layouts of the code processing the different sensor data. The joint optimization of code layout and the order in which the different sensors should be sampled—in order to maximize code cache reuse—turns out to be a difficult combinatorial optimization problem. But our experiments show that optimizing the sampling order of the sensors has a much larger influence on cache reuse, compared to the effects that different code layouts have. Based on this, we also propose a heuristic that obtains near-optimal solutions in jointly optimizing both code layout as well the sensor sampling order. Our case study using a faint fall detection application—from the geriatric care domain—which is fed by a number of smart sensors to detect physiological and physical gait signals of a patient show very attractive power consumption in the underlying processor. Alternatively, our method can be used to improve the sampling frequency of the sensors, leading to higher reliability and better response time of the application.