A Phosphorescent Nanoparticle‐Based Probe for Sensing and Imaging of (Intra)Cellular Oxygen in Multiple Detection Modalities

Monitoring cell and tissue oxygenation is important for the analysis of cell development and differentiation, mitochondrial function, and common (patho)physiological conditions such as ischemia, cancer, neurodegenerative disorders. A number of materials for sensing cellular oxygen (O₂) by optical means have been described in recent years, but the diverse range of biological models and measurement tasks demands more versatile, flexible, and simple O₂ sensors. A new cell‐penetrating phosphorescent nanosensor material called MM2 probe is presented. In it, the highly photostable phosphorescent reporter dye Pt(II)‐5,10,15,20‐tetrakis‐(2,3,4,5,6‐pentafluorophenyl)‐porphyrin (PtTFPP; emission at 650 nm) and poly(9,9‐dioctylfluorene) (PFO) fluorophore act as Förster resonance energy transfer (FRET) donor and two‐photon antennae are embedded in cationic hydrogel nanoparticles. Such probe formulation provides efficient delivery into the cell and subsequent sensing and high‐resolution imaging of cellular O₂ in different detection modalities, including ratiometric intensity and phosphorescence lifetime‐based sensing under one‐photon and two photon excitation. MM2 probe combines high brightness, photo‐ and chemical stability, low toxicity, and ease of fabrication and use. Its versatility and analytical performance are demonstrated in physiological experiments with adherent cells and neurospheres representing 2D and 3D respiring objects and detection on time‐resolved fluorescent readers, confocal and multiphoton microscopes, and customized microsecond fluorescence/phosphorescence lifetime imaging microscopy (FLIM) systems.     

Suppression of overtone oscillation and low‐current operation using novel‐design scheme for quartz crystal oscillators

A novel design is proposed for a low‐frequency quartz crystal oscillator circuit. Negative resistance in a low‐frequency CMOS‐inverter quartz oscillator was reviewed for the fundamental mode at 32 kHz and the overtone oscillation at 200 kHz. Suppression of the overtone oscillation, appropriate gain, and drive current reduction are realized by adding only three circuit components. Experimental results and an estimate of the absolute value of the negative resistance are presented for the conventional Colpitts circuit and two types of the quartz crystal oscillator circuit. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Research and development of transgenic plants in Malaysia: an example from an Asian developing country

In 2000, agriculture contributed 13% to the national gross domestic product of Malaysia. The country of 23 million people has created a competitive program coordinated by the Ministry of Science, Technology and the Environment, research institutions, and universities to undertake biotechnology research in several areas. Intensified research efforts are under way on oil palm, rubber, rice, papaya, and orchids. Although the most progress has been made in rice and papaya, no transgenic crop is ready for field trials. Nonetheless, preliminary steps have been taken to prepare for the trials, and detailed testing protocols are being developed.     

Processing of a multi‐layer polyetheretherketone composite for use in acetabular cup prosthesis

The hydroxyapatite polyetheretherketone (HAPEEK) as a non‐degradable bioactive polymer composite material with coating of hydroxyapatite (HA) as a bioactive ceramic material can enhance the osteointegration of carbon fiber reinforced polyetheretherketone (CFRPEEK) as a non‐degradable bioinert polymer composite. This study describes the joining process of CFRPEEK and HAPEEK beam components and coating process of HA on the HAPEEK substrate to achieve the multi‐layer PEEK composite for use in the application of acetabular cup prosthesis. The CFRPEEK and HAPEEK components were ultrasonically welded while the HA was plasma sprayed on the HAPEEK substrate. Ultrasonic welding parameters (length and direction of the energy directors at the interface, welding time, and pressure) were investigated by single cantilever beam and lap shear tests to achieve the optimum bonding strength of CFRPEEK and HAPEEK components. Plasma spraying parameters (e.g., surface speed, powder feed, current, primary gas flow, and system voltage) were altered to achieve the good adhesion of HA coating on the HAPEEK substrate, which was evaluated by scratch test. The results showed that the proposed multi‐layer composite was successfully processed by carrying out the ultrasonic welding and plasma spraying coating processes. The outcomes of this study could be used to develop a non‐metal acetabular cup prosthesis using the proposed multi‐layer composition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40915.     

Multilingual Anaphora Resolution

This paper presents amultilingual robust, knowledge-poor approach to resolvingpronouns in technical manuals. This approach is a modification of the practicalapproach (Mitkov 1998a) and operates on texts pre-processed by apart-of-speech tagger. Input is checked against agreementand a number of antecedent indicators. Candidates are assigned scores by eachindicator and the candidate with the highest aggregate score isreturned as the antecedent. We propose this approach as aplatform for multilingual pronoun resolution. The robust approach was initiallydeveloped and tested for English, but we have also adaptedand tested it for Polish and Arabic. For bothlanguages, we found that adaptation required minimummodification and that further, even if used unmodified, the approachdelivers acceptable success rates. Preliminary evaluation reports high successrates in the range of over 90%.     

Chromatographic separation and multicollection-ICPMS analysis of iron. Investigating mass-dependent and -independent isotope effects

A procedure was developed that allows precise determination of Fe isotopic composition. Purification of Fe was achieved by ion chromatography on AG1-X8 strongly basic anion-exchange resin. No isotopic fractionation is associated with column chemistry within 0.02 per thousand /amu at 2sigma. The isotopic composition was measured with a Micromass IsoProbe multicollection inductively coupled plasma hexapole mass spectrometer. The Fe isotopic composition of the Orgueil CI1 carbonaceous chondrite, which best approximates the solar composition, is indistinguishable from that of IRMM-014 (-0.005 +/- 0.017 per thousand /amu). The IRMM-014 reference material is therefore used for normalization of the isotopic ratios. The protocol for analyzing mass-dependent variations is validated by measuring geostandards (IF-G, DTS-2, BCR-2, AGV-2) and heavily fractionated Fe left after vacuum evaporation of molten wüstite (FeO) and solar (MgO-Al(2)O(3)-SiO(2)-CaO-FeO in chondritic proportions) compositions. It is shown that the isotopic composition of Fe during evaporation of FeO follows a Rayleigh distillation with a fractionation factor alpha equal to (m(1)/m(2)()1/2), where m(1) and m(2) are the masses of the considered isotopes. This agrees with earlier measurements and theoretical expectations. The isotopic composition of Fe left after vacuum evaporation of solar composition also follows a Rayleigh distillation but with a fractionation factor (1.013 22 +/- 0.000 67 for the (56)Fe/(54)Fe ratio) that is lower than the square root of the masses (1.018 35). The protocol for analyzing mass-independent variations is validated by measuring terrestrial rocks that are not expected to show departure from mass-dependent fractionation. After internal normalization of the (57)Fe/(54)Fe ratio, the isotopic composition of Fe can be measured accurately with precisions of 0.2epsilon and 0.5epsilon at 2sigma for (56)Fe/(54)Fe and (58)Fe/(54)Fe ratios, respectively (epsilon refers to relative variations in parts per 10 000). For (58)Fe, this precision is an order of magnitude better than what had been achieved before. The method is applied to rocks that could potentially exhibit mass-independent effects, meteorites and Archaean terrestrial samples. The isotopic composition of a 3.8-Ga-old banded iron formation from Isua (IF-G, Greenland), and quartz-pyroxene rocks from Akilia and Innersuartuut (GR91-26 and SM/GR/171770, Greenland) are normal within uncertainties. Similarly, the Orgueil (CI1), Allende (CV3.2), Eagle Station (ESPAL), Brenham (MGPAL), and Old Woman (IIAB) meteorites do not show any mass-independent effect.     

Unfolding and Aggregation of Lysozyme under the Combined Action of Dithiothreitol and Guanidine Hydrochloride: Optical Studies

Using a number of optical techniques (interferometry, dynamic light scattering, and spectroscopy), denaturation of hen egg white lysozyme (HEWL) by treatment with a combination of dithiothreitol (DTT) and guanidine hydrochloride (GdnHCl) has been investigated. The denaturing solutions were selected so that protein denaturation occurred with aggregation (Tris-HCl pH = 8.0, 50 mM, DTT 30 mM) or without aggregation (Tris-HCl pH = 8.0, 50 mM, DTT 30 mM, GdnHCl 6 M) and can be evaluated after 60 min of treatment. It has been found that denatured by solution with 6 M GdnHCl lysozyme completely loses its enzymatic activity after 30 min and the size of the protein molecule increases by 1.5 times, from 3.8 nm to 5.7 nm. Denaturation without of GdnHCl led to aggregation with preserving about 50% of its enzymatic activity. Denaturation of HEWL was examined using interferometry. Previously, it has been shown that protein denaturation that occurs without subsequent aggregation leads to an increase in the refractive index (Δn ~ 4.5 × 10⁻⁵). This is most likely due to variations in the HEWL–solvent interface area. By applying modern optical techniques conjointly, it has been possible to obtain information on the nature of time-dependent changes that occur inside a protein and its hydration shell as it undergoes denaturation.