Magnetically Driven Silver‐Coated Nanocoils for Efficient Bacterial Contact Killing

The increasing threat of multidrug‐resistant bacterial strains against conventional antibiotic therapies represents a significant worldwide health risk and intensifies the need for novel antibacterial treatments. In this work, an effective strategy to target and kill bacteria using silver‐coated magnetic nanocoils is reported. The coil palladium (Pd) nanostructures are obtained by electrodeposition and selective dealloying, and subsequently coated with nickel (Ni) and silver (Ag) for magnetic manipulation and antibacterial properties, respectively. The efficiency of the nanocoils is tested in the treatment of Gram‐negative Escherichia coli (E. coli) and Gram‐positive methicillin‐resistant Staphylococcus aureus (S. aureus), both of which represent the leading multidrug‐resistant bacterial pathogens. The nanocoils show highly effective bacterial killing activity at low concentrations and in relatively short durations of treatment time. Three different investigation techniques, LIVE/DEAD assay, colony‐forming unit counting, and scanning electron microscope, reveal that the antibacterial activity is a result of bacterial membrane damage caused by direct contact with the nanocoil. The low cytotoxicity toward fibroblast cells along with the capability of precise magnetic locomotion makes the proposed nanocoil an ideal candidate to combat multidrug‐resistant bacteria in the field of biomedical and environmental applications.     

Microflora of the sour dough of wheat flour bread IX. Biochemical characteristics and baking performance of wheat doughs elaborated with mixtures of pure microorganisms

Summary Changes in mono- and disaccharides and acetic and lactic acid production of six different straight doughs elaborated with combinations of pure strains of yeastsSaccharomyces cerevisiae andCandida boidinii and lactic acid bacteriaLactobacillus plantarum andStreptococcus sp have been investigated, as well as the baking quality of the resulting breads. The type and proportion of the fermentative microorganisms were found to influence the biochemical activity of the doughs. The sugar levels after mixing reached different proportions, depending on the type of sugar and the type of microorganisms used. After proofing, the glucose and fructose content of the doughs decreased to 0.01%–0.02% db and maltose decreased to 0.45%–0.11 % db. Acetic and lactic acids underwent variable changes during fermentation, depending on the type of dough. Lactic acid showed higher levels than acetic acid. Bread made from these doughs had different sensory characteristics, texture, edibility and overall acceptance, as well as different lactic and acetic acid contents, depending on the mixture of microorganisms inoculated.

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Biochemische Merkmale und Leistungsfahigkeit der mit Mischungen reiner Mikroorganismen hergestellten Weizenbackteige

Zusammenfassung Die Forschungsaufgabe befaßte sich mit den Veranderungen der Mono- und Disaccharide, mit der Entstehung von Essig- und Milchsaure in sechs Teigen, die mit Kombinationen reiner HefekulturenSaccharomyces cerevisiae undCandida boidinii und MilchsäurebakterienLactobacillus plantarum undStreptococcus sp hergestellt waren und mit den sich daraus ergebenden Qualitätsmerkmalen der Brote. Die Art und Anteile der Mikroorganismen übten einen entscheidenden Einfluß auf die biochemische Aktivität der Teige aus. Nach dem Knetvorgang konnten unterschiedliche Gehalte gemäß der eingesetzten Saccharide und Mikroorganismen festgestellt werden. Der Glucose- und Fructoseanteil der fermentierten Teige verringerte sich auf 0,01–0,02% t. g., der Maltoseanteil auf 0,45-0,11% t.g. In den einzelnen Teigen veranderten sich wahrend der Garung die Essig-und Milchsauregehalte unterschiedlich. Bei der Milchsaure konnte eine grbBere Zunahme und somit höhere Endgehalte als bei der Essigsaure festgestellt werden. Die mit diesen Teigen hergestellten Brote erreichten verschiedene Textureigenschaften (Weichheit der Krume) und sensorische Merkmale, insbesondere Kaufahigkeit und Geschmack Bowie einen, entsprechend der Mikroorganismenmischung, höheren oder geringeren Milch- und Essigsäuregehalt.

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Presented at the 8th International Cereal and Bread Congress, Lausanne, Switzerland, June 1988.

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This paper is a part of a doctoral thesis     

Noninvasive infrared thermometry for application in skin biology.I. Model measurements and local measurements on the dorsal surface ofthe rabbit

Understanding thermal energy distribution is essential to interpret skin temperature for diagnosing various pathological and experimental conditions. The present paper investigates temperature data measurements acquired with an infrared thermometer system and in vivo temperature measurements on the backs of New Zealand rabbits. Local differences in skin temperature are significant around bony structures and in visceral areas. The results suggest that the location of experimental sites must be considered when interpreting data which use local temperature as an indicator of microvascular phenomena on the skin surface. Our techniques have proven valuable for quantifying thermal effects on small fields or skin lesions of experimental animals, and can be used noninvasively to measure the onset and transient vascular effects caused by noxious insults including laser radiation.     

Emerging gallium nitride based devices

Wide bandgap GaN has long been sought for its applications to blue and UV emitters and high temperature/high power electronic devices. Recent introduction of commercial blue and blue-green LED's have led to a plethora of activity in all three continents into the heterostructures based on GaN and its alloys with AlN and InN. In this review, the status and future prospects of emerging wide bandgap gallium nitride semiconductor devices are discussed. Recent successes in p-doping of GaN and its alloys with InN and AlN, and in n-doping with much reduced background concentrations have paved the way for the design, fabrication, and characterization of devices such as MESFET's, MISFET's, HBT's, LED's, and optically pumped lasers. We discuss the electrical properties of these devices and their drawbacks followed by future prospects. After a short elucidation of materials characteristics of the nitrides, we explore their electrical transport properties in detail. Recent progress in processing such as formation of low-resistance ohmic contacts and etching is also presented. The promising features of quarternaries and double heterostructures in relation to possible current injection lasers, LED's, and photodetectors are also elaborated on     

Practical Harmonic Cancellation Techniques for the On-Chip Implementation of Sinusoidal Signal Generators for Mixed-Signal BIST Applications

Harmonic cancellation strategies have been recently presented as a promising solution for the efficient on-chip implementation of accurate sinusoidal signal generators. Classical harmonic cancellation techniques consist in combining a set of time-shifted and scaled versions of a periodical signal in such a way that some of the harmonic components of the resulting signal are cancelled. This signal manipulation strategy can be easily implemented using digital resources to provide a set of phase-shifted digital square-wave signals and a summing network for scaling and combining the phase-shifted square-waves. A critical aspect in the practical implementation of the harmonic cancellation technique is the stringent accuracy required for the scaling weight ratios between the different phase-shifted signals. Small variations between these weights due to mismatch and process variations will reduce the effectiveness of the technique and increase the magnitude of undesired harmonic components. In this work, different harmonic cancellation strategies are presented and analyzed with the goal of simplifying the practical on-chip implementation of the scaling weights. Statistical behavioral simulations are provided in order to demonstrate the feasibility of the proposed approach.     

Determination of Thermoelectric Module Efficiency: A Survey

The development of thermoelectrics (TE) for energy conversion is in the transition phase from laboratory research to device development. There is an increasing demand to accurately determine the module efficiency, especially for the power generation mode. For many TE, the figure of merit, ZT, of the material sometimes cannot be fully realized at the device level. Reliable efficiency testing of thermoelectric modules is important to assess the device ZT and provide end-users with realistic values for how much power can be generated under specific conditions. We conducted a general survey of efficiency testing devices and their performance. The results indicated a lack of industry standards and test procedures. This study included a commercial test system and several laboratory systems. Most systems are based on the heat flow meter method, and some are based on the Harman method. They are usually reproducible in evaluating thermoelectric modules. However, different systems often showed large differences that are likely caused by uncertain heat loss and thermal resistance. Efficiency testing is an important capability for the thermoelectric community to improve. A follow-up international standardization effort is planned.     

Can multiscale traffic analysis be used to differentiate Internet applications?

An accurate mapping of Internet traffic to applications can be important for a broad range of network management and measurement tasks, including traffic engineering, service differentiation, performance/failure monitoring and security. Traditional mapping approaches have become increasingly inaccurate because many applications use non-default or ephemeral port numbers, use well-known port numbers associated with other applications, change application signatures or use traffic encryption. In this paper we will demonstrate that multiscale traffic analysis based on multi-order wavelet spectrum can be used as a discriminator of Internet applications traffic profiles. By performing clustering analysis over the multiscale wavelet spectrum coefficients that are inferred from the measured traffic, the proposed methodology is able to efficiently differentiate different IP applications without using any payload information. This characteristic will allow the differentiation of traffic flows in unencrypted and encrypted scenarios. In order to compare the differentiating potential of different traffic application data, upload, download and joint upload and download flow statistics are considered to evaluate the identification approach for each selected protocol. Moreover, we also evaluate which timescales and spectrum orders are more relevant for the traffic differentiation. From the analysis of the obtained results we can conclude that the proposed methodology is able to achieve good identification results using a small set of timescales of a single order wavelet spectrum of a general raw traffic statistic.     

A wavelet-based ECG delineator: evaluation on standard databases

In this paper, we developed and evaluated a robust single-lead electrocardiogram (ECG) delineation system based on the wavelet transform (WT). In a first step, QRS complexes are detected. Then, each QRS is delineated by detecting and identifying the peaks of the individual waves, as well as the complex onset and end. Finally, the determination of P and T wave peaks, onsets and ends is performed. We evaluated the algorithm on several manually annotated databases, such as MIT-BIH Arrhythmia, QT, European ST-T and CSE databases, developed for validation purposes. The QRS detector obtained a sensitivity of Se = 99.66% and a positive predictivity of P+ = 99.56% over the first lead of the validation databases (more than 980,000 beats), while for the well-known MIT-BIH Arrhythmia Database, Se and P+ over 99.8% were attained. As for the delineation of the ECG waves, the mean and standard deviation of the differences between the automatic and manual annotations were computed. The mean error obtained with the WT approach was found not to exceed one sampling interval, while the standard deviations were around the accepted tolerances between expert physicians, outperforming the results of other well known algorithms, especially in determining the end of T wave.     

Effect of constrained fast power control on cellular DS-CDMAsystems with base station diversity

An approach is presented for determining the effect of limiting the power transmitted by a mobile user in a cellular DS-CDMA system with fast power control under multipath fading. It is shown that the system capacity can be increased if very deep fades are not compensated