Quantum Zeno and anti-Zeno effects: without the rotating-wave approximation

We show that the counterrotating, neglected in the previous studies of the quantum Zeno effect (QZE) in atomic decay, can have a large impact on the short-time evolution. We calculate the electron self-energy, the Lamb shift, and the QZE without making the rotating-wave approximation (RWA) and show that, for hydrogen in free space, the Zeno time is longer by 2 orders of magnitude than that obtained from the RWA. We also show that there is no anti-Zeno effect as the counterrotating terms and rotating terms represent the opposite processes in the higher frequency region. Consequently, the experimental measurement of the QZE may be much easier than what was determined with the RWA results.

Effects of functional electrical stimulation relating to leg movement

Functional electrical stimulation (FES) has grown to be an effective and important element in the biomedical industry over the years. Due to this fact, it has become the basis of many researches. However, much work is focused on the theory and control technique with very few relating experiments. In this work, some key experiments were performed on the leg muscles during the leg movement. Some useful results were obtained with regards to muscle reaction, in terms EMG readings. The stimulus of the FES system was also applied to the muscles during the leg movement. The readings of experiments reveal some important muscle properties which are verified accordingly.

Full-length dystrophin gene transfer to the mdx mouse in utero

In utero gene therapy for genetic diseases, such as muscular dystrophies, offers potential advantages over postnatal treatment including vector delivery at the earliest point in the disease and treatment prior to full maturation of the immune system. This study examines in utero gene delivery of full-length murine dystrophin to the murine mdx model for Duchenne muscular dystrophy using a high-capacity adenoviral vector. We examined dystrophin expression, spread of vector, morphology and specific force production of the tibialis anterior muscle 9 weeks after intramuscular in utero injection. Recombinant dystrophin was expressed in the hindlimb muscles, with the majority of animals having expression in two muscles of the injected hindlimb. The dystrophin-glycoprotein complex was restored in those muscle fibers expressing recombinant dystrophin. Analysis of the percentage of dystrophin-expressing muscle fibers with centrally placed nuclei revealed effective protection from cycles of degeneration and regeneration normally seen in muscle fibers lacking dystrophin. However, due to low levels of muscle gene transfer, further advances in the efficiency of adenoviral vector-mediated gene delivery would be required for clinical applications of in utero gene therapy for primary myopathies such as Duchenne muscular dystrophy.

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.

Troglitazone induces gastric cancer cell line MKN45 apoptosis

AIM: To observe the effects of different concentrations of troglitazone on the activity of peroxisome proliferators-activated receptor γ (PPARγ), and apoptosis of the MKN45 gastric cell line.

METHODS: Cultured MKN45 gastric cells were randomly divided into four groups: control, 1, 5 and 10 μmol/L troglitazone. The change in activity of PPARγ was detected by electrophoretic mobility shift assay (EMSA). Flow cytometry was used to detect changes in the expression of caspase-3, cell cycle and apoptosis.

RESULTS: TPPARγ activity of cultured MKN45 gastric cells increased significantly with the concentration of troglitazone. Data were quantified for the control group as 100, the mean activity of 1 μmol/L troglitazone was 155.8, 5 μmol/L was 218.7, and 10 μmol/L was 307.6 (P < 0.01). Flow cytometry confirmed that the mean expression of caspase-3 protein was increased to 4.51, 10.95, 20.49, 33.56 with increasing concentration of troglitazone. The cells in G0/G1 stage increased steadily and those in S stage decreased at the same time (P < 0.01). The rate of apoptosis also increased.

CONCLUSION: Troglitazone could activate PPARγ and cell-cycle arrest and apoptosis of MKN45 gastric cells. PPARγ may become a new target in the treatment of gastric cancer.

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.

Tip60 functions as a potential corepressor of KLF4 in regulation of HDC promoter activity

KLF4 is a transcription factor that is highly expressed in the gastrointestinal tract. Previously we have demonstrated that KLF4 represses HDC promoter activity in a gastric cell line through both an upstream Sp1 binding GC box and downstream gastrin responsive elements. However, the mechanism by which KLF4 inhibits HDC promoter is not well defined. In the current study, by using yeast two-hybrid screening, Tip60 was identified as a KLF4 interacting protein. Further coimmunoprecipitation and functional reporter assays support the interaction between these two proteins. In addition, Tip60 and HDAC7, previously shown to interact with each other and repress transcription, inhibited HDC promoter activity in a dose-dependent fashion. Consistently, knock down of Tip60 or HDAC7 gene expression by specific shRNA increased endogenous HDC mRNA level. Co-immunoprecipitation assays showed that HDAC7 was pulled down by KLF4 and Tip60, suggesting that these three proteins form a repressive complex. Further chromatin immuno-precipitation indicated that all three proteins associated with HDC promoter. Two-hour gastrin treatment, known to activate HDC gene expression, significantly decreased the association of KLF4, Tip60 and HDAC7 with HDC promoter, suggesting that gastrin activates HDC gene expression at least partly by decreasing the formation of KLF4/Tip60/HDAC7 repressive complexes at the HDC promoter.

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.

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.