Tuning pH sensitivities of zinc phthalocyanines in ionic liquid modified matrices

Phthalocyanine dyes are clinically important bright fluorophores with many desirable properties. Their absorption and emission maxima in near infrared region make them proper tool for optical probing of biologically relevant materials and optical-chemical-sensing purposes. In this work we have shown that pH sensitivities of the phthalocyanines can be manipulated as desired. This property makes the Pcs very proper photosensitizers for photodynamic therapy applications. In this work pH sensitivities of alpha (α) and beta (β) tetra-substituted zinc phthalocyanines (ZnPcs) were studied spectroscopically in ethyl cellulose and PVC matrices. In experiments designed to manipulate pH, lipophilic room temperature ionic liquids (RTILs) were added into the test environment. The RTIL-modified thin films provided higher relative fluorescence intensity changes upon exposure to proton with respect to the RTIL-free ones. By this way, acidity constants of the ZnPcs could be tuned to the desired region of interest. The ZnPcs, exhibited good reproducibility and reversibility upon protonation. The RTILs also enhanced short and long term stabilities of the Pc-dyes. There was no significant drift in their proton sensitivities even after 10 assays and after being stored in a buffer condition for over six months.     

Effect of basic pumice on morphologic properties of interfacial transition zone in load-bearing lightweight/semi-lightweight concretes

The objective of this research is to determine the effect of basic pumice on morphologic properties of interfacial transition zone in load-bearing lightweight/semi-lightweight concretes. In this respect, it has been researched how the chemical and physical structure and the volumetric ratio of basic pumice affected the following three morphologic properties of interfacial transition zone: compactness, width and physical adherence. In accordance with the stated purpose, 15 concrete serials with various properties were produced using basic pumice as aggregate and 670 images were taken from the samples collected from these serials via scanning electron microscope (SEM). Semi-analytical detections were performed based on non-generalizing numeric data obtained in conclusion of the determination of grain limits in these images and comments on visual analysis. In accordance with these detections, it has been concluded that the basic pumice has a high level of potential to contribute to the morphologic properties of interfacial transition zone.     

AuthorSupportTool – besser wissenschaftlich arbeiten

Wie unterstützt man den Schreibprozess einer wissenschaftlichen Arbeit mit modernen Textverarbeitungssystemen? Einige Antworten auf diese Frage sind im AuthorSupportTool implementiert, das eine Erweiterung für den OpenOffice.org 3 Writer darstellt. Hauptmerkmale des AuthorSupportTools sind eine Quellen- und Zitatverwaltung, eine Versionsverwaltung zur Unterstützung kooperativer Arbeit sowie ein grafischer Editor mit Mindmap-Funktion, um Themen, Notizen und Querverbindungen zu verwalten.     

A maintenance strategy for systems subjected to deteriorationgoverned by random shocks

The authors examine the time-stationary availability of maintained systems that deteriorate according to a random-shock process. System failures are not self-announcing; hence, failures must be detected via inspection. The approach considers randomly occurring shocks that cumulatively damage the system; shock magnitudes are taken as random. The authors develop an expression for computing system availability when inspections follow a renewal process. This expression leads to a proved proposition showing that, for any specified mean inspection rate, system availability is maximized by choosing deterministic inter-inspection times     

Executive functions, information sampling, and decision making in narcolepsy with cataplexy.

Objective: Narcolepsy with cataplexy (NC) affects neurotransmitter systems regulating emotions and cognitive functions. This study aimed to assess executive functions, information sampling, reward processing, and decision making in NC. Method: Twenty-one NC patients and 58 healthy participants performed an extensive neuropsychological test battery. Results: NC patients scored as controls in executive function tasks assessing set shifting, reversal learning, working memory, and planning. Group differences appeared in a task measuring information sampling and reward sensitivity. NC patients gathered less information, tolerated a higher level of uncertainty, and were less influenced by reward contingencies than controls. NC patients also showed reduced learning in decision making and had significantly lower scores than controls in the fifth block of the IOWA gambling task. No correlations were found with measures of sleepiness. Conclusions: NC patients may achieve high performance in several neuropsychological domains, including executive functions. Specific differences between NC patients and controls highlight the importance of the hypocretin system in reward processing and decision making and are in line with previous neuroimaging and neurophysiological studies. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Novel hands-free interaction techniques based on the software switch approach for computer access with head movements

Head-operated computer accessibility tools (CATs) are useful solutions for the ones with complete head control; but when it comes to people with only reduced head control, computer access becomes a very challenging task since the users depend on a single head-gesture like a head nod or a head tilt to interact with a computer. It is obvious that any new interaction technique based on a single head-gesture will play an important role to develop better CATs to enhance the users’ self-sufficiency and the quality of life. Therefore, we proposed two novel interaction techniques namely HeadCam and HeadGyro within this study. In a nutshell, both interaction techniques are based on our software switch approach and can serve like traditional switches by recognizing head movements via a standard camera or a gyroscope sensor of a smartphone to translate them into virtual switch presses. A usability study with 36 participants (18 motor-impaired, 18 able-bodied) was also conducted to collect both objective and subjective evaluation data in this study. While HeadGyro software switch exhibited slightly higher performance than HeadCam for each objective evaluation metrics, HeadCam was rated better in subjective evaluation. All participants agreed that the proposed interaction techniques are promising solutions for computer access task.

     

Design of a 4.2–5.4 GHz differential LC VCO using 0.35 μm SiGe BiCMOS technology for IEEE 802.11a applications

In this paper, a 4.2–5.4 GHz, ?Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 μm SiGe BiCMOS process that includes high‐speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post‐layout simulation results, phase noise is ?110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and ?113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation‐mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm² on Si substrate, including DC and RF pads. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Dimension reduction by a novel unified scheme using divergence analysis and genetic search

In this study, a unified scheme using divergence analysis and genetic search is proposed to determine significant components of feature vectors in high-dimensional spaces, without having to deal with singular matrix problems.In the literature it is observed that three main problems exist in the feature selection process performed in a high-dimensional space. These problems are high computational load, local minima, and singular matrices. In this study, feature selection is realized by increasing the dimension one by one, rather than reducing the dimension. In this sense, the recursive covariance matrices are formulated to decrease the computational load. The use of genetic algorithms is proposed to avoid local optima and singular matrix problems in high-dimensional feature spaces. Candidate strings in the genetic pool represent the new features formed by increasing the dimension. The genetic algorithms investigate the combination of features which give the highest divergence value.In this study, two methods are proposed for the selection of features. In the first method, features in a high-dimensional space are determined by using divergence analysis and genetic search (DAGS) together. If the dimension is not high, the second method is offered which uses only recursive divergence analysis (RDA) without any genetic search. In Section 3 two experiments are presented: Feature determination in a two-dimensional phantom feature space, and feature determination for ECG beat classification in a real data space.