Antioxidant activities of seed extracts from Dalbergia odorifera T. Chen

The heartwood or root of Dalbergia odorifera T. Chen is an important traditional Chinese medicine. Antioxidant activities of seed extracts from D. odorifera T. Chen were first investigated in this study. Ethanolic extracts were suspended in distilled water and partitioned successively with petroleum ether, ethyl acetate, n-butanol (n-BuOH) and water, yielding four extracts named as PE, EE, BE and WE, respectively. The EE exhibited the highest total phenolic, total flavonoid, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, linoleic acid and lard peroxidation inhibition, but lowest chelating ability. Liquid chromatography mass spectrometry (LC/MS) analysis of EE revealed that there was a predominant component with negative molecular ion [M-H]- at m/z 373.2, a fragment at m/z 343.2 and UV λmax at 263 and 297nm. The mechanisms of antioxidant activities of seed extracts were exploited. Positive linear correlations were observed between reducing power and DPPH radical scavenging activity (R2 = 0.836), and linoleic acid peroxidation inhibition (R2 = 0.920), respectively. Similarly, high positive linear correlations of the total phenolic and total flavonoid with DPPH radical scavenging activity, reducing power and linoleic acid peroxidation inhibition were observed. This study therefore suggests that seeds of D. odorifera T. Chen have the potential to be used as natural antioxidants in food or pharmaceutical industry.Key words: Antioxidant activity, Dalbergia odorifera T. Chen, seed, liquid chromatography mass spectrometry (LC/MS)

Responsive Nanogel Probe for Ratiometric Fluorescent Sensing of pH and Strain in Hydrogels

In this study a new pH-responsive nanogel probe containing a complementary nonradiative resonance energy transfer (NRET) fluorophore pair is investigated and its ability to act as a versatile probe of network-related changes in three hydrogels demonstrated. Fluorescent sensing using NRET is a powerful method for studying relationships between Angstrom length-scale structure and macroscopic properties of soft matter. Unfortunately, inclusion of NRET fluorophores into such materials requires material-specific chemistry. Here, low concentrations of preformed nanogel probes were included into hydrogel hosts. Ratiometric photoluminescence (PL) data for the gels labeled with the nanogel probes enabled pH-triggered swelling and deswelling to be studied as well as Ca2+-triggered collapse and solute release. PL measurements during compression of a nanogel probe-labeled nanocomposite gel demonstrated mechanochromic behavior and strain sensing. The new nanogel probes have excellent potential for investigating the internal structures of gels and provide a versatile ratiometric fluorescent platform for studying pH and strain

Synthesis and Evaluation of [F-18]FEtLos and [F-18]AMBF(3)Los as Novel F-18-Labelled Losartan Derivatives for Molecular Imaging of Angiotensin II Type 1 Receptors

Losartan is widely used in clinics to treat cardiovascular related diseases by selectively blocking the angiotensin II type 1 receptors (AT(1)Rs), which regulate the renin-angiotensin system (RAS). Therefore, monitoring the physiological and pathological biodistribution of AT(1)R using positron emission tomography (PET) might be a valuable tool to assess the functionality of RAS. Herein, we describe the synthesis and characterization of two novel losartan derivatives PET tracers, [F-18]fluoroethyl-losartan ([F-18]FEtLos) and [F-18]ammoniomethyltrifluoroborate-losartan ([F-18]AMBF(3)Los). [F-18]FEtLos was radiolabeled by F-18-fluoroalkylation of losartan potassium using the prosthetic group 2-[F-18]fluoroethyl tosylate; whereas [F-18]AMBF(3)Los was prepared following an one-step F-18-F-19 isotopic exchange reaction, in an overall yield of 2.7 +/- 0.9% and 11 +/- 4%, respectively, with high radiochemical purity (>95%). Binding competition assays in AT(1)R-expressing membranes showed that AMBF(3)Los presented an almost equivalent binding affinity (K-i 7.9 nM) as the cold reference Losartan (K-i 1.5 nM), unlike FEtLos (K-i 2000 nM). In vitro and in vivo assays showed that [F-18]AMBF(3)Los displayed a good binding affinity for AT(1)R-overexpressing CHO cells and was able to specifically bind to renal AT(1)R. Hence, our data demonstrate [F-18]AMBF(3)Los as a new tool for PET imaging of AT(1)R with possible applications for the diagnosis of cardiovascular, inflammatory and cancer diseases

Known and unknown requirements in healthcare

We report experience in requirements elicitation of domain knowledge from experts in clinical and cognitive neurosciences. The elicitation target was a causal model for early signs of dementia indicated by changes in user behaviour and errors apparent in logs of computer activity. A Delphi-style process consisting of workshops with experts followed by a questionnaire was adopted. The paper describes how the elicitation process had to be adapted to deal with problems encountered in terminology and limited consensus among the experts. In spite of the difficulties encountered, a partial causal model of user behavioural pathologies and errors was elicited. This informed requirements for configuring data- and text-mining tools to search for the specific data patterns. Lessons learned for elicitation from experts are presented, and the implications for requirements are discussed as “unknown unknowns”, as well as configuration requirements for directing data-/text-mining tools towards refining awareness requirements in healthcare applications

Rapid assembly of customized TALENs into multiple

Transcriptional activator-like effector nucleases (TALENs) have become a powerful tool for genome editing. Here we present an efficient TALEN assembly approach in which TALENs are assembled by direct Golden Gate ligation into Gateway® Entry vectors from a repeat variable di-residue (RVD) plasmid array. We constructed TALEN pairs targeted to mouse Ddx3 subfamily genes, and demonstrated that our modified TALEN assembly approach efficiently generates accurate TALEN moieties that effectively introduce mutations into target genes. We generated "user friendly" TALEN Entry vectors containing TALEN expression cassettes with fluorescent reporter genes that can be efficiently transferred via Gateway (LR) recombination into different delivery systems. We demonstrated that the TALEN Entry vectors can be easily transferred to an adenoviral delivery system to expand application to cells that are difficult to transfect. Since TALENs work in pairs, we also generated a TALEN Entry vector set that combines a TALEN pair into one PiggyBac transposon-based destination vector. The approach described here can also be modified for construction of TALE transcriptional activators, repressors or other functional domains. © 2013 Zhang et al