Nano-structured TiO(2) film fabricated at room temperature and its acoustic properties

Nano-structured TiO(2) thin film has been successfully fabricated at room temperature. Using a quarter wavelength characterization method, we have measured the acoustic impedance of this porous film, which can be adjusted from 5.3 to 7.19 Mrayl by curing it at different temperatures. The uniform microstructure and easy fabrication at room temperature make this material an excellent candidate for matching layers of ultra-high frequency ultrasonic imaging transducers.

Surface effects on the orbital order in the single-layered manganite La0.5Sr1.5MnO4

The question of how bulk electronic order is terminated at a surface is an intriguing one, and one with possible practical implications--for example in nanoscaled systems that may be characterized by their surface behaviour. One example of such order is orbital order, and in principle it should be possible to probe the termination of this order with surface X-ray scattering. Here, we report the first observation of the scattering arising from the termination of bulk orbital order at the surface of a crystal--so-called 'orbital truncation rods'. The measurements, carried out on a cleaved perovskite, La(0.5)Sr(1.5)MnO(4), reveal that whereas the crystallographic surface is atomically smooth, the orbital 'surface', which is observed through the atomic displacements caused by the orbital order, is much rougher, with a typical scale of the surface roughness of approximately 7 degrees A. Interestingly, the temperature dependence of this scattering shows evidence of a surface-induced second-order transition.

Structural and Optical Isomers of Nonamethoxy Cyclotriveratrylene: Separation and Physical Characterization

The paper concerns the structural and optical isomers of nonamethoxy-tribenzocyclononene (compound 1). In the first part of the paper it is shown that 1 exists in two structural isomers: a rigid crown (c-1) with C3 symmetry and a flexible saddle (s-1) with C1 symmetry. The latter, not previously known, can be prepared from the as-synthesized c-1 by quenching a hot solution (or the melt) followed by HPLC separation. The crown/saddle equilibrium, isomerization kinetics, and associated thermodynamic parameters in various organic solvents are reported. Carbon-13 MAS NMR, X-ray diffraction, and differential scanning calorimetry (DSC) of polycrystalline c-1 and s-1 racemates are also reported. The different melting points of the isomers and their rapid isomerization in the melt result in unconventional DSC thermograms involving multiple endothermic and exothermic transitions. The second part of the paper concerns the chiral properties of 1. Both the saddle and crown isomers are structurally chiral, but due to the fast pseudorotation of s-1 in solution, it cannot be separated into its enantiomers. Those of c-1 were separated by HPLC using a chiral column. Their X-ray structure and melting points differ considerably from those of the racemate. This and their fast racemization in the melt lead to complex DSC thermograms with multiple transitions. Solutions of the neat enantiomers exhibit a relatively small specific optical rotation. In the UV they show circular dichroism for the B1u and B2u transitions, with the latter exhibiting a clear couplet structure. Infrared and vibrational circular dichroism spectra of the enantiomers in solution are reported. Comparison of these spectra with quantum mechanical simulations provides unambiguous identification of the enantiomers.

Genetic manipulation of the mouse via gene targeting in embryonic stem cells

Gene targeting applied to totipotent embryonic stem (ES) cells is a very powerful means of creating highly specific mutations of genes in the mouse. The successful application of this technology is however constrained by both the types of mutations that can be generated at a target locus and the ability to reconstruct a germline chimera from the manipulated cells. We have developed two cell lines that can be routinely transmitted through the germline of chimeras after cloning and prolonged selection in tissue culture. We have also established a variety of methods for generating non-selected mutations at the X-linked hprt locus in ES cells. Our observations at this locus have enabled us to generate successfully a subtle mutation at the non-selectable Hox-2.6 locus.

Neurorescue Activity, APP Regulation and Amyloid-β Peptide Reduction by Novel Multi-Functional Brain Permeable Iron- Chelating- Antioxidants,M-30 and Green Tea Polyphenol, EGCG

Accumulation of iron at sites where neurons degenerate in Parkinson's disease (PD) and Alzheimer's disease (AD) is thought to have a major role in oxidative stress induced process of neurodegeneration. The novel non-toxic lipophilic brain- permeable iron chelators, VK-28 (5- [4- (2- hydroxyethyl) piperazine-1-ylmethyl]- quinoline- 8- ol) and its multi-functional derivative, M-30 (5-[N-methyl-N-propargylaminomethyl]-8-hydroxyquinoline), as well as the main polyphenol constituent of green tea (-)-epigallocatechin-3-gallate (EGCG), which possesses iron metal chelating, radical scavenging and neuroprotective properties, offer potential therapeutic benefits for these diseases. M-30 and EGCG decreased apoptosis of human SH-SY5Y neuroblastoma cells in a neurorescue, serum deprivation model, via multiple protection mechanisms including: reduction of the pro-apoptotic proteins, Bad and Bax, reduction of apoptosis-associated Ser139 phosphorylated H2A.X and inhibition of the cleavage and activation of caspase-3. M-30 and EGCG also promoted morphological changes, resulting in axonal growth-associated protein-43 (GAP-43) implicating neuronal differentiation. Both compounds significantly reduced the levels of cellular holo-amyloid precursor protein (APP) in SH-SY5Y cells. The ability of theses novel iron chelators and EGCG to regulate APP are in line with the presence of an iron-responsive element (IRE) in the 5'-untranslated region (5'UTR) of APP. Also, EGCG reduced the levels of toxic amyloid-beta peptides in CHO cells over-expressing the APP "Swedish" mutation. The diverse molecular mechanisms and cell signaling pathways participating in the neuroprotective/neurorescue and APP regulation/processing actions of M-30 and EGCG, make these multifunctional compounds potential neuroprotective drugs for the treatment of neurodegenerative diseases, such as PD, AD, Huntington's disease and amyotrophic lateral sclerosis.

Increased asynchronous release and aberrant calcium channel activation in amyloid precursor protein deficient neuromuscular synapses

Despite the critical roles of the amyloid precursor protein (APP) in Alzheimer's disease pathogenesis, its physiological function remains poorly established. Our previous studies implicated a structural and functional activity of the APP family of proteins in the developing neuromuscular junction (NMJ). Here we performed comprehensive analyses of neurotransmission in mature neuromuscular synapse of APP deficient mice. We found that APP deletion led to reduced paired-pulse facilitation and increased depression of synaptic transmission with repetitive stimulation. Readily releasable pool size and total releasable vesicles were not affected, but probability of release was significantly increased. Strikingly, the amount of asynchronous release, a measure sensitive to presynaptic calcium concentration, was dramatically increased, and pharmacological studies revealed that it was attributed to aberrant activation of N- and L-type Ca(2+) channels. We propose that APP modulates synaptic transmission at the NMJ by ensuring proper Ca(2+) channel function.

Prevention and restoration of lactacystin-induced nigrostriatal dopamine neuron degeneration by novel brain-permeable iron chelators

Dysfunction of the ubiquitin-proteasome system (UPS) and accumulation of iron in substantia nigra (SN) are implicated in the pathogenesis of Parkinson's disease (PD). UPS dysfunction and iron misregulation may reinforce each other's contribution to the degeneration of dopamine (DA) neurons. In the present study, we use a new brain-permeable iron chelator, VK-28 [5-(4-(2-hydroxyethyl) piperazin-1-yl (methyl)-8-hydroxyquinoline], and its derivative M30 [5-(N-methyl-N-propargyaminomethyl)-8-hydroxyquinoline] in vivo to test their neuroprotective and neurorestorative properties against proteasome inhibitor (lactacystin) -induced nigrostriatal degeneration. Bilateral microinjections of lactacystin (1.25 microg/side) into the mouse medial forebrain bundle were performed. Administration of VK-28 (5 mg/kg, once a day) or M30 (5 mg/kg, once a day) was applied intraperitoneally 7 days before or after the lactacystin microinjection until the mice were sacrificed 28 days after microinjection. We found that VK-28 and M30 both significantly improved behavioral performances and attenuated lactacystin-induced DA neuron loss, proteasomal inhibition, iron accumulation, and microglial activation in SN. In addition, M30 restored the Bcl-2 level, which was suppressed after lactacystin injection. These findings suggest that brain-permeable iron chelators can improve DA neuron survival under UPS impairment. Furthermore, M30, a derivative of VK-28 and neuroprotective agent rasagiline, may serve as a better neuroprotective therapy for PD.

Suppressed magnetization at the surfaces and interfaces of ferromagnetic metallic manganites

What happens to ferromagnetism at the surfaces and interfaces of manganites? With the competition between charge, spin, and orbital degrees of freedom, it is not surprising that the surface behaviour may be profoundly different to that of the bulk. Using a powerful combination of two surface probes, tunnelling and polarized x-ray interactions, this paper reviews our work on the nature of the electronic and magnetic states at manganite surfaces and interfaces. The general observation is that ferromagnetism is not the lowest energy state at the surface or interface, which results in a suppression or even loss of ferromagnetic order at the surface. Two cases will be discussed ranging from the surface of the quasi-2D bilayer manganite (La(2-2x)Sr(1+2x)Mn(2)O(7)) to the 3D perovskite (La(2/3)Sr(1/3)MnO(3))/SrTiO(3) interface. For the bilayer manganite, which is ferromagnetic and conducting in the bulk, these probes present clear evidence for an intrinsic insulating non-ferromagnetic surface layer atop adjacent subsurface layers that display the full bulk magnetization. This abrupt intrinsic magnetic interface is attributed to the weak inter-bilayer coupling native to these quasi-two-dimensional materials. This is in marked contrast to the situation for the non-layered manganite system (La(2/3)Sr(1/3)MnO(3)/SrTiO(3)), whose magnetization near the interface is less than half the bulk value at low temperatures and decreases with increasing temperature at a faster rate than that for the bulk.

Anti-tumor activity of letrozole in patients with recurrent advanced low malignant potential or low-grade serous ovarian tumors

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Purpose: To evaluate the clinical activity of oral Letrozole in patients with recurrent and advanced low malignant potential or low grade serous ovarian tumors and to determine the impact of steroid receptor expression on this observed activity. Methods: In a phase II design, we recruited patients with confirmed recurrent advanced stage low malignant potential tumors and recurrent low-grade serous carcinomas. Measurable disease was required. Steroid hormone expression (ER and PR), EGFR, and Her2/neu expression were determined on available pathological material by IHC from the initial surgery or at documentation of recurrent disease and blood was obtained before enrollment and every other month while on therapy. Letrozole was administered orally at a dose of 2.5 mg once a day. The endpoints were objective response rate assessed by Response Evaluation Criteria in Solid Tumor. Adverse events were graded using the National Cancer Institute Common Toxicity Criteria. Results: Thirteen patients meeting eligibility have been enrolled are evaluable for response and toxicity. From objective clinical parameters (RECIST) no patients had a CR or PR; five patients (38%) had disease stabilizations, eight patients had progressive disease. However, using criteria for CA 125 response, we obtained a complete serologic response in 2 of 13 patients (15%), and a partial serologic response in 2 additional patients (15%); marker stabilization was seen in 5 other patients (38%). CA125 increased in four patients (31%). We also detected the presence of ER, PR, EGFR, Her-2/Neu by IHC, and estradiol in the plasma by ELISA. No significant correlation was observed between tumor marker response and ER expression alone. However, when we evaluated the co-expression of ER/PR we found 3 of 5 (60%) patients had a serologic response compared to just 1 of 8 patients with ER+/PR- tumors (P=0.07). We observed no severe adverse events. Conclusion: Our preliminary data suggests that oral Letrozole has some antitumor activity in recurrent advanced low grade or borderline ovarian tumors and is well tolerated. The analysis of correlation between objective response and combined prediction markers including phosphorylated ER, PR, AKT, and IGFR is ongoing (Supported by CTRF).

No significant financial relationships to disclose.

Electrically assisted magnetic recording in multiferroic nanostructures

We demonstrate the room-temperature control of magnetization reversal with an electric field in an epitaxial nanostructure consisting of ferrimagnetic nanopillars embedded in a ferroelectric matrix. This was achieved by combining a weak, uniform magnetic field with the switching electric field to selectively switch pillars with only one magnetic configuration. On the basis of these experimental results, we propose to use an electric field to assist magnetic recording in multiferroic systems with high perpendicular magnetic anisotropy.

Novel neuroprotective neurotrophic NAP analogs targeting metal toxicity and oxidative stress: potential candidates for the control of neurodegenerative diseases

A large body of data indicates that a cascade of events contributes to the neurodegeneration in Alzheimer's disease (AD) and Parkinson's disease (PD). Metal (Fe, Cu, Zn) dyshomeostasis and oxidative stress are believed to play a pivotal role in the pathogenesis of these diseases. Accordingly, multifunctional compounds combining metal chelating and antioxidative activity hold a great promise as potential drugs for treating AD and PD. In this study, two novel NAPVSIPQ (NAP) analogs (M98 and M99) with potential antioxidant-metal chelating ability were designed and investigated, aiming to improve the poor metal chelating and antioxidative activity of NAP. Our studies showed that both M98 and M99 formed stable metal (Fe, Cu, Zn) complexes in water and demonstrated good metal (Fe, Cu, Zn) chelating properties as opposed to the poor metal (Fe, Cu, Zn) chelating properties of their parent peptide NAP. M98 and M99 exhibited significant inhibition of iron-induced lipid peroxidation in rat brain homogenates at concentrations of > or = 30 microM, while NAP failed to show any inhibition even at 100 microM. In human neuroblastoma cell (SH-SY5Y) culture, M98 and M99 at 1 microM completely protected against 6-hydroxydopamine (6OHDA) toxicity with potency similar to NAP and desferal (DFO), a strong iron chelator and a highly potent radical scavenger. In PC12 cell culture, M98 at the range of 0.001-1 microM displayed potent protection against 6-OHDA toxicity, comparable to NAP and DFO. These results suggest that M98 and M99 deserve further investigation as potential drug candidates for neuroprotection.

Hormonal therapy in ovarian cancer

Ovarian carcinoma continues to be the leading cause of death due to gynecological malignancy. Epidemiologic studies indicate that steroid hormones play roles in ovarian carcinogenesis. Gonadotropins, estrogen, and androgen may be causative factors, while gonadotropin-releasing hormone and progesterone may be protective factors in ovarian cancer pathogenesis. Experimental studies have shown that hormonal receptors are expressed in ovarian cancer cells and mediate the growth-stimulatory or growth-inhibitory effects of the hormones on these cells. Hormonal therapeutic agents have been evaluated in several clinical trials. Most of these trials were conducted in patients with recurrent or refractory ovarian cancer, with modest efficacy and few side effects. Better understanding of the mechanisms through which hormones affect cell growth may improve the efficacy of hormonal therapy. Molecular markers that can reliably predict major clinical outcomes should be investigated further in well-designed trials.

New protocol for leg ulcer tissue classification from colour images

Measurement of wound healing status is very important for monitoring progress in individual patients. Tissue classification is a vital step in the development of an automatic measurement system for wound healing assessment. We present a new tissue classification protocol using the RGB (Red, Green and Blue) histogram distributions of pixel values from wound color images. These three histogram distributions (extracted features) were used as three two-dimensional (2D) input signals for classification. This protocol has been carried out using the KNN classifier and results show that the proposed protocol provides an extremely competent practical method for the classification of wound tissues.

Reentrant orbital order and the true ground state of LaSr2Mn2O7

Contrary to conventional wisdom, our purified La 2-2x Sr 1+2x Mn2O7 crystals exhibit CE-type orbital and charge order as the low-temperature ground state for a hole doping level h=0.5. For small deviations from h=0.5, the high-temperature CE phase is replaced at low temperatures by an A-type antiferromagnet without coexistence. Larger deviations result in a lack of CE order at any temperature. Thus, small inhomogeneities in cation or oxygen composition could explain why others commonly see this reentrance with coexistence.

Prospective, multi-centre clinic-based evaluation of four rapid diagnostic tests for syphilis

OBJECTIVES

To evaluate prospectively four rapid, point-of-care serological tests for syphilis in prenatal or high risk populations in four countries.

METHODS

Tests were performed on consecutive clinic attenders, using whole blood in the clinic, and whole blood and serum in the laboratory. The sensitivity and specificity of each test was evaluated, using a standard treponemal test (Treponema pallidum haemagglutination assay (TPHA) or fluorescent treponemal antibody, absorbed (FTA-ABS) as gold standard. Non-treponemal tests (rapid plasma reagin (RPR) or venereal diseases research laboratory (VDRL) tests) were also performed on all subjects at three sites.

RESULTS

The specificity of each rapid test was >95% at each site. Sensitivities varied from 64-100% and, in most cases, were lower when whole blood was used rather than serum.

CONCLUSIONS

Rapid serological tests for syphilis are an acceptable alternative to conventional laboratory tests. Since they do not require equipment or electricity, they could increase coverage of syphilis screening, and enable treatment to be given at the first clinic visit.

An auditory vigilance task for mental fatigue detection

An Auditory Vigilance Task (AVT) as a validation criterion for monitoring mental fatigue was proposed in this study. The biological basis of this task design is on the understanding that mental fatigue is a cortical deactivation. This AVT is simple to perform, free of learning curve and independent on acquired skills (aptitude, knowledge). The validity and sensitivity of this task was verified by a scientifically controlled 25-hour fatigue experiment recorded by Electroencephalogram (EEG). Results showed that this AVT is highly sensitive to changes during fatigue process. The effectiveness of this AVT was compared to one subjective rating scale (FSS). The 5-level fatigue EEG datasets (labeled by AVT and FSS respectively) were fed into Support Vector Machines (SVM). SVM test accuracy indicated that AVT is more effective than subject's own estimation. The results demonstrate conclusively that this AVT is suitable for fatigue detection study as a reliable validation criterion.

Key Feature Extraction for Fatigue Identification using Random Forests

Electroencephalogram (EEG) might be the most predictive and reliable physiological indicator of mental fatigue. However, the extraction of key features from massive EEG data for mental fatigue identification remains a challenge. The objective of this study is to identify the key EEG features in relationship to mental fatigue, from a broad pool of EEG features generated by quantitative EEG (qEEG) techniques, using Random Forests (RF), which is a recently developed machine learning algorithm. The method is applied to key EEG feature extraction for 5-level mental fatigue identification using the five subjects' EEG data recorded in 25-hour fatigue experiments. RF produces significant feature reduction with little compromise of the classification performance. The identified key EEG features also indicate that electrode locations in frontal and occipital regions of the brain are most important for adequate representation of the deactivation of functional lobes of the brain, which is consistent with the anatomical areas known to be involved in mental fatigue. It is also interesting to discover that the four frequency bands are all important for the mental fatigue identification.

Adaptive PI Regulation of Blood Pressure of Hypertension patients

This paper presents an adaptive PI control of mean blood pressure using vasoactive drugs like SNP. A new algorithm updating variations in time delay and sensitivity of the system is proposed and its effectiveness is discussed. For demonstration, simulations under clinical conditions are carried out and the results show that the adaptive control system can effectively handle the changes in patient's dynamics and provide satisfactory performance in regulation of blood pressure of hypertension patients.